Online ISSN
1750-0443
Micro & Nano Letters
Volume 7, Issue 12, December 2012
Volumes & issues:
Volume 7, Issue 12
December 2012
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- Author(s): Qing-An Huang and Shanhong Xia
- Source: Micro & Nano Letters, Volume 7, Issue 12, page: 1157 –1157
- DOI: 10.1049/mnl.2012.0943
- Type: Article
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- Author(s): Q. Wang ; Z.P. Cao ; H. Kuwano
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1158 –1161
- DOI: 10.1049/mnl.2012.0581
- Type: Article
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This study presents a lead zirconate titanate (PZT) energy harvester with stainless steel (SUS 304) substrate the resonance frequency of which is lower than 100 Hz. The PZT thick films had been directly and successfully deposited on SUS substrates by the sol-gel method with a thickness of 4 µm. Then the deposited films were evaluated by the X-ray diffraction method and the scanning electron microscopy method. Energy harvesters were fabricated and their performance was measured under various vibration conditions. Optimal output power and resonant frequency are 15 µW and 89 Hz, respectively, when the devices were tested under 1 g acceleration vibration and connected with a 23 kΩ resistor. - Author(s): Jui-En Hu ; Shu-Ying Yang ; Jung-Chuan Chou ; Po-Hao Shih
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1162 –1165
- DOI: 10.1049/mnl.2012.0529
- Type: Article
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Flexible dye-sensitised solar cells (FDSSCs) which have different quantities of arrayed titanium dioxide (TiO2) working electrode for parallel modules are introduced. FDSSCs are usually fabricated as a module type instead of single cell to enhance conversion efficiency and characteristic parameters. The general FDSSCs modules are designed as parallel strip-shaped and as parallel interconnection types, and there are some advantages such as easy fabrication, low cost and simple structure. In this reported study, the active areas of FDSSCs are the same (0.48 cm2), and they have different quantities of TiO2 thin films. The single strip-shaped TiO2 working electrode has a larger internal resistance than more quantities of TiO2 thin films. Therefore, and they have fabricating the different quantities of arrayed flexible TiO2 working electrodes is the better method to solve the problem, higher internal resistance than single TiO2 thin film. As a result, the FDSSC, which has the triple strip-shaped TiO2 working electrode, has a higher conversion efficiency (0.25%) than other different quantities of TiO2 thin films. - Author(s): Hexin Xing ; Xiaohong Wang ; Caiwei Shen ; Siwei Li
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1166 –1169
- DOI: 10.1049/mnl.2012.0563
- Type: Article
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Presented is a microsupercapacitor using SU-8 photoresist as the separator, featuring by high-aspect-ratio three-dimensional (3D) electrodes and high capacity per unit area. A scalable and mechanically stable structure for microsupercapacitors has been designed. By combining the preparation strategy for self-supporting nanoporous electrodes with micromachining technologies for high-aspect-ratio structures, 3D electrodes that allow for a heavy load of electrode material per unit area has been achieved. Electrochemical characterisation results of the prototype using ionic liquid as the electrolyte demonstrate that the microsupercapacitor exhibits a high specific energy of 330 mJcm−2 and a large specific capacitance of 160 mFcm−2, which are attributed to both the high-performance materials and the well-designed microstructure. This device can be potentially applied to various energy systems, such as electronic backup power supplies and microenergy storage devices. - Author(s): Jin Y. Zhang ; Ziping Cao ; Qi Wang ; Hiroki Kuwano
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1170 –1172
- DOI: 10.1049/mnl.2012.0545
- Type: Article
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By analysing the energy flow in a piezoelectric generator, it was revealed that the mechanical factor, electromechanical coupling coefficient and dielectric loss of the generator have significant influence on its energy conversion efficiency. Based on this analysis, aluminium nitrate (AlN) thin films deposited on stainless steel (SUS) were selected to substitute lead titanate zirconate thin films deposited on single-crystal Si for fabricating miniature devices. These thin films were prepared with an electron cyclotron resonance sputtering system. The influences of the surface modification (polishing or coating a Pt/Ti thin layer) of SUS substrates on c-axis orientation, piezoelectric coefficient and effective coupling coefficient of AlN thin films were investigated. - Author(s): Peihong Wang ; Xuhan Dai ; Zhuoqing Yang ; Zhongzhu Wang ; Xiaolin Zhao
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1173 –1175
- DOI: 10.1049/mnl.2012.0561
- Type: Article
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Three electromagnetic vibration energy scavengers with electroplated Ni springs have been designed, fabricated and characterised. Prototype I consists of a coil, an Ni spring on a silicon frame and a permanent magnet. Prototypes II and III are with a sandwich structure and consist of two coils, an Ni spring and a permanent magnet. There are air channels in the silicon frame in prototype III. These prototypes were fabricated using microelectromechanical systems microfabricating techniques. The experimental results show the electroplated Ni spring is a nonlinear and hardened one, so the spring–magnet system has a different resonant frequency under different excited vibration. The tested results show that prototype III has the highest output voltage and output power. The maximal load voltage is 157.5 mV and the maximal load power is 21.7 µW for prototype III when it is excited by vibration with 280.9 Hz frequency and 0.8 g acceleration. - Author(s): Yin Bai ; Jianhua Tong ; Chao Bian ; Guili Yan ; Beilei Deng ; Hong Zhang ; Shanhong Xia
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1176 –1179
- DOI: 10.1049/mnl.2012.0519
- Type: Article
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In this study, the characterisation and calibration of microfabricated cobalt electrodes for the detection of total phosphorus (TP) in water are presented. The microelectrode chips were fabricated by microelectromechanical systems technology, and cobalt was used as the sensing material modified on the surface of microelectrodes using the electrodepositing method. The surface morphology and crystal direction of modified cobalt were examined and the electrochemical characterisation of cobalt electrodes was performed. The cobalt microelectrode showed good linear response to phosphate in the range of 10−6–10−2 M/l with the slope of about 28 mV/dec. The microelectrodes also presented good stability, consistency and reproducibility. These electrodes were applied to detect TP concentration in water samples from a lake. Calibration was performed for each electrode before the test. The test result using these cobalt microelectrodes was consistent with the concentration given in the certificate of qualified water of the quality detection institute. - Author(s): Zhongliang Yu ; Yulong Zhao ; Xiawei Meng ; Bian Tian ; Zhuangde Jiang
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1180 –1183
- DOI: 10.1049/mnl.2012.0549
- Type: Article
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Presented is a piezoresistive absolute micro pressure sensor, which is of great benefit for altitude location. In this investigation, the design, fabrication and testing of the sensor are carried out. By analysing the stress distribution on sensitive elements using the finite-element method (FEM), a novel structure through the introduction of beams into the standard bossed diaphragm is built up. The proposed configuration presents its advantages in terms of sensitivity and overload resistance compared with the standard bossed diaphragm and conventional plane diaphragm structures. The sensor is fabricated based on silicon bulk micromachining technology, and the detailed processing program is discussed. Calibration data obtained through measurements are in good agreement with the results of the FEM analysis. Testing results demonstrate that the sensor features a high sensitivity of 11.098 µV/V/Pa in the operating range of 500 Pa at room temperature, and a high-overload resistance (200 times overload) to protect it from being destroyed under atmospheric environment. Owing to the excellent performance, the sensor can be applied for measuring absolute micro pressure lower than 500 Pa. - Author(s): Lidong Du ; Zhan Zhao ; Li Xiao ; Zhen Fang ; Qing Tian ; Xuejin Sun ; Xiaolei Wang
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1184 –1188
- DOI: 10.1049/mnl.2012.0552
- Type: Article
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A nickel–chromium (Ni–Cr) piezoresistive pressure sensor is presented, which has the advantages of low-cost and easy fabrication processes. In the designed sensor, Ni–Cr alloy (80:20 wt%), which can be fabricated using simple processes, is used as the strain-detecting material with a smaller but acceptable gauge factor. Eutectic-bonding technology, based on silver–tin (Ag–Sn) alloy, which contains 3.5 wt% Ag and has 20 µm thickness, is used as an alternative and easy bonding choice to complete the vacuum package. Normally, Ag–Sn alloy is mostly obtained by the electrochemical deposition method. However, here the Ag–Sn solder film is directly used as a bonding material. It reduces the fabrication difficulty of eutectic bonding of the proposed pressure sensor. By studying the processes of annealing of Ni–Cr fabrication and eutectic bonding with Ag–Sn, the authors complete the alloy piezoresistive atmosphere pressure sensor. Bonding quality is evaluated by inspection through the deflection of a diaphragm of silicon with more than 95% of the area successfully bonded. The pressure–voltage characteristic test results suggest a precision within 0.3% in square fitting. The temperature coefficient offset is 620 ppm/(°C free space optic (FSO)). - Author(s): A.G.P. Kottapalli ; M. Asadnia ; J.M. Miao ; C.W. Tan ; G. Barbastathis ; M. Triantafyllou
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1189 –1192
- DOI: 10.1049/mnl.2012.0604
- Type: Article
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Blind cave fish are capable of sensing flows and movements of nearby objects even in dark and murky water conditions with the help of arrays of pressure-gradient sensors present on their bodies called lateral-lines. To emulate this functionality of lateral-lines for autonomous underwater vehicles, an array of polymer MEMS pressure sensors have been developed that can transduce underwater pressure variations generated by moving objects. Individual sensors are fabricated using liquid crystal polymer as a membrane material, which gives high robustness and reliability, and higher sensitivity compared with its silicon counterparts. The individual sensor in the array achieves a sensitivity of 90 mV/(m/s) with a high resolution of 25 mm/s. The underwater object detection capability of the array is demonstrated through proof-of-concept experiments. The array is capable of determining the velocity and distinguishing various distances of an underwater stimulus with high accuracy and repeatability. - Author(s): N.A. Ahmad Ridzuan ; S. Masuda ; N. Miki
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1193 –1196
- DOI: 10.1049/mnl.2012.0560
- Type: Article
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Flexible and highly-sensitive capacitive sensors that are capable of detecting pressure distribution on curved surfaces are now in demand. Using solid dielectric material could limit the sensors flexibility, while using air as the dielectric might compromise the sensors sensitivity. Proposed is a distributed capacitive sensor that contains highly dielectric liquid, which increases the sensor sensitivity while maintaining their flexibility. Since the liquid used in this work is incompressible, an escape reservoir is used that allows the liquid between the electrodes to flow into the reservoir when external pressure is applied and the gap between the electrode decreases. In prior work, the escape reservoir was designed to be alongside the sensing area, which resulted in a large footprint. A sensor has been designed that contains encapsulated highly dielectric liquid and allows the liquid to escape beneath the sensing area. The footprint was successfully reduced by 75%. The encapsulated liquid enhanced the maximum measurable pressure from 100 kPa to 800 kPa. The amplification ratios of the sensitivity with DI water and glycerine increased 7 and 3.5 times respectively, as compared to the device without the liquid encapsulated. - Author(s): Yang Li ; Jizhou Sun ; Chao Bian ; Jianhua Tong ; Shanhong Xia
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1197 –1201
- DOI: 10.1049/mnl.2012.0533
- Type: Article
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A microsensor chip was fabricated by micro electromechanical system technology, and a portable electrochemical system for nitrate determination in freshwaters was developed. As the electrocatalyst material, copper was electrodeposited onto the working-electrode of the microsensor by the cyclic voltammetry method. It was found that the deposited layer was porous and constructed by copper nanoclusters. The electrochemical response of the modified microsensor for nitrate under acidic conditions (pH=2.0) was characterised by linear sweep voltammetry. Calibration in standard nitrate samples in the range of 6.25–300 µmol/l yielded straight lines: y1 [µA]=−0.0526x–3.905 (R12=0.9993), while in the range of 300–3500 µmol/l yielded straight lines: y2 [µA]=−0.0353x–13.653 (R22=0.9918). It was found that the modified microsensor performed at higher sensitivity in nitrate detection than previous works and the limit of detection is 5 µmol/l (S/N≥3). Interference analysis with nine kinds of ions (NO2−, Cl−, HPO42−/PO43−, SO42−, HCO3−/CO32−, Na+ and K+) commonly found in water indicated that only NO2− causes reasonable interference (i.e. 10% signal distortion). Based on the modified microsensor, the developed portable electrochemical system was employed for nitrate determination in three freshwater samples. The results were in good agreement with the data obtained by the ultraviolet spectrophotometric method. - Author(s): Chen Fu ; Inki Jung ; Sang-sik Yang ; Keekeun Lee
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1202 –1205
- DOI: 10.1049/mnl.2012.0569
- Type: Article
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A Love wave biosensor, which is composed of a one-port surface acoustic wave reflective delay line on a piezoelectric substrate, a thin overlayer (waveguide layer) on top of the substrate, and a sensitive film that responds only to a specific cell, was optimally designed on a 41° YX LiNbO3 substrate and then fabricated according to the extracted design parameters. Based on multilayer theory, polymethylmethacrylate waveguide thickness was optimised. For derivation of the coupling of mode parameters, the periodic using the periodic finite-element method/boundary element method modelling was utilised. Optimal interdigital transducers and reflectors' features were determined to realise high-quality reflection peaks. The experimentally measured reflection coefficient S11 showed good agreement with simulated results. The evaluated sensitivity was 11.5 deg/µg/ml in terms of anti-DNP immunoglobulin G absorption. - Author(s): Shuhu Chen ; Nannan Li ; Jing Chen
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1206 –1209
- DOI: 10.1049/mnl.2012.0585
- Type: Article
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A report is presented on the modelling and verification of microneedle-skin interactions. A nonlinear finite element model based on the micro biomechanical properties of skin was established to simulate a microneedle being inserted into the skin. The deformation of skin and the force-displacement behaviour of the microneedle could be obtained. The accuracy was experimentally verified by measuring the relationship between force and displacements during insertion into mouse skin. With this model, the influences of different geometries on microneedle fracture were discussed, which was useful to optimise the microneedle design. - Author(s): R. Shimane ; S. Kumagai ; M. Hori ; M. Sasaki
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1210 –1212
- DOI: 10.1049/mnl.2012.0555
- Type: Article
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A micro plasma-nozzle device has been fabricated for plasma treatment for a single cell. The micro plasma-nozzle device consists of through-hole and trench structures. The nozzle device was attached to a guide tube (O.D.: φ1.5 mm, I.D.: φ1 mm) of an atmospheric pressure microplasma. Once plasma gas was supplied into the guide tube, most of the plasma gas was exhausted through trench structures, whereas the remaining plasma was excited through the nozzle hole. The nozzle device with φ5 µm holes achieved minimum plasma irradiation onto a PDMS film. The plasma-modified area was φ5.4–5.6 µm, which was much smaller than the area size modified by direct plasma irradiation from the guide tube (φ3–4 mm). The plasma irradiation caused protrusions on the PDMS surface. The minimised plasma irradiation formed 170 nm-height-protrusion-structures on the PDMS surface. The plasma irradiation through the nozzle device was applied to an onion tissue using a nozzle device with φ10 µm holes. The plasma irradiation formed φ10–15 µm holes in the onion cell membrane. - Author(s): T. Kano ; T. Inaba ; K. Higashi ; N. Miki
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1213 –1216
- DOI: 10.1049/mnl.2012.0556
- Type: Article
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A microbial chip is demonstrated that immobilises microbes into micro holes using positive dielectrophoresis (DEP) for efficient screening. The DEP frequency was set at 10 MHz, which was found to be most effective to selectively immobilise live bacteria. The media including reactive agents can be flown into the chip continuously and therefore the reaction products can be continuously collected. Immobilisation of microbes enables quantification of the number of microbes involved in the reaction and makes their reactions conditions consistent. These advantages enable the proposed microbial chip to evaluate the production capacity of a single bacterium. To demonstrate it, the developed microbial chip was used to characterise microbes and evaluate biological activity. First, Corynebacterium bacterium was used as a sample bacteria. The chip successfully revealed the production capacity of lactic acid by a single C. bacterium. It was experimentally found that the production rate of lactic acid of Corynebacterium glutamicum increased 1.7 times and 3.8 times by adding pyruvic acid and sodium bicarbonate, respectively. Secondly, microbes belonging to the Corynebacterium group with respect to the lactic acid production were screened. Corynebacterium variabile was experimentally found to be the most productive among three tested members. The proposed microbial chip is readily applicable to an efficient microbial screening platform and potentially a reliable microbial sensor given the capacity of quantifying the total number of bacteria involved in the microbial reaction. - Author(s): Wei Zhang ; Yun Zeng ; Peng Wei ; Zhiyong Wang ; Jian Lu ; Qingrong Wei ; Gang Liu
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1217 –1219
- DOI: 10.1049/mnl.2012.0452
- Type: Article
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Collagen has been widely used as biomaterials for its excellent biocompatibility and the potential to guide tissue regeneration. Based on the inducing regeneration concept, collagen/biphasic calcium phosphate microspheres (BCP) were prepared by utilising emulsion polymerisation and the intrinsic self-assembly of collagen. The bioactivity of the micro collagen/BCP composites was preliminarily evaluated by in vitro co-culture with mesenchymal stem cells (MSCs) and the results indicated that the composites can provide an appropriate environment for the proliferation and osteogenic differentiation of MSCs and have a potential clinical application in the bone tissue engineering field. - Author(s): Nannan Li ; Shuwei He ; Qiancheng Zhao ; Shibin Zhang ; Jing Chen
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1220 –1222
- DOI: 10.1049/mnl.2012.0582
- Type: Article
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In this study, substrates with a large topography were aligned and bonded, and a spray-coated SU-8 was employed as the adhesive layer between two complementary non-planar surfaces. Both wafer-level and chip-level bonding were carried out with an alignment tolerance of 5 µm. The bonding pairs exhibited enhanced tensile strength and shearing strength compared to that of the planar surface bonding, which was influenced by the gap between the bonding surfaces. This technology meets the requirements of the wafer-level three-dimensional structure transfer and opens up possibilities for manufacturing more complicated microelectromechanical systems devices. - Author(s): F. Kurokawa ; R. Yokokawa ; H. Kotera ; F. Horikiri ; K. Shibata ; T. Mishima ; M. Sato ; I. Kanno
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1223 –1225
- DOI: 10.1049/mnl.2012.0570
- Type: Article
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Micro fabrication has been conducted for sodium potassium niobate [(K,Na)NbO3, KNN] thin films by dry etching and Pt/KNN/Pt unimorph micro cantilevers have been fabricated as a lead-free piezoelectric micro electro mechanical system (MEMS). KNN etching by Ar/C4F8 plasma showed a high etching rate of about 60 nm/min and KNN/Cr selectivity of over 5. Tip displacement of the Pt/KNN/Pt micro cantilevers was measured and the frequency response and piezoelectric properties were evaluated. Young's modulus and piezoelectric coefficients d31 of the KNN thin film were estimated to be 115 GPa and −99 to 219 pm/V, respectively. These results indicate that Ar/C4F8 plasma etching does not degrade the piezoelectric properties of KNN thin films and enables one to fabricate various lead-free piezoelectric MEMS applications. - Author(s): Tao Deng ; Mengwei Li ; Chenxu Zhao ; Jian Qin ; Cangran Guo ; Zewen Liu
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1226 –1229
- DOI: 10.1049/mnl.2012.0551
- Type: Article
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Aiming to meet the ever-increasing challenge of a low cost, portable and real-time sensitive detection polymerase chain reaction (PCR) system, a novel in situ electrochemical detection static micro PCR (EC-SµPCR) chip is designed and fabricated. The 10×10 mm EC-SµPCR chip comprises 12 micro reaction chambers, and each 1500×1000×60 µm chamber consists of three modules: a micro heater, a micro temperature sensor and a micro three-electrode system (MTES). Heating, cooling and electrochemical cyclic voltammetry (CV) experiments were carried out to investigate the performance characteristics of each module of the chamber in the EC-SµPCR chip. The results showed that the heating rate of the chip was 1.05°Cs−1 with only one micro heater, whereas the cooling rate was 1.01°Cs−1 with natural air cooling. It is worth noting that the bare MTES of the chamber directly detected the oxidation of single-stranded DNA (ssDNA, 10−6 M) with the CV method, furthermore, the oxidation peak current of ssDNA can be increased about 40% after a prepolarisation step. All three modules of the chamber in the EC-SµPCR chip work efficiently and reliably, which reveals that the entire chip is ready for further analysis trials. - Author(s): Junbo Wang ; Yanlong Shang ; Jian Chen ; Zhenguo Sun ; Deyong Chen
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1230 –1233
- DOI: 10.1049/mnl.2012.0536
- Type: Article
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A new micro-machined resonant accelerometer with a differential structure enabling the detection of out-of-plane acceleration is described. The microaccelerometer consists of two sensitive structures composed of seismic masses, flexural hinges and double-clamped resonant beams. Owing to thickness differences and neutral axis variations among these three components, in response to an out-of-plane acceleration, the movements of the seismic masses lead to stress build up in flexural hinges, further translated as axial forces applied on resonant beams. In this differential design, under acceleration, one resonant beam is under a tensile stress, whereas the other one is under a compressive stress, producing a differential resonant frequency output. The microaccelerometer was fabricated by a silicon-direct-bonding silicon-on-insulator wafer with MEMS fabrication and a low-stress packaging method was also developed. Based on a closed-loop control circuit for resonant beam excitation and detection, device characterisation was conducted, producing a quality factor of 436 in air and a differential sensitivity of 813 Hz/g. - Author(s): Jili Liu ; Deyong Chen ; Junbo Wang
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1234 –1236
- DOI: 10.1049/mnl.2012.0550
- Type: Article
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Presented is a method that can regulate the resonant frequency and the quality factor (Q-factor) of an electromagnetic vibrating ring gyroscope by electronic tuning. A novel circuit is designed to control the drive mode of the electromagnetic vibrating ring gyroscope. The circuit consists of an amplifier and a phase shifter used for feedback control. The frequency split can be reduced and the Q-factor can be improved through this method. Experimental results show that the frequency shift of the drive mode can be from −6.41 to 6.38 Hz when the phase of the feedback signal shifts ±90° compared with the drive signal. The Q-factor in the air can be improved from 522 to 821 when the phase of the feedback signal is not shifted. The sensitivity tests show the effectiveness of the control circuit. - Author(s): Zhao Xing-hai ; Shan Guang-cun ; Du Yi-jia ; Bao Jing-fu ; Zhu Hao-shen ; Zheng Ying-bin ; Shek Chan-hung ; Cheng Yong-sheng
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1237 –1240
- DOI: 10.1049/mnl.2012.0567
- Type: Article
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A G-band microelectromechanical system (MEMS) rectangular waveguide iris filter is designed and fabricated. The effects of the metallised layer and iris thickness, and roughness, on filter main performances are investigated. The prototypes were fabricated using MEMS manufacturing techniques. The key technique problems including deep etching, electroplating and bonding are researched and settled. The measured insertion loss can get to be 1.5–2.0 dB, the central frequency is 174 GHz, the bandwidth is 9.6 GHz, and the isolation out of the bandpass is larger than 15 dB. The test results show that the radio frequency MEMS filter meets practical requirements, which proves that it is a successful example for fabricating such rectangular waveguide devices at one to several hundred gigahertz frequencies using such presented processes.
Editorial: APCOT 2012 Special Issue
Metal-based piezoelectric energy harvesters by direct deposition of PZT thick films on stainless steel
Fabrication of flexible dye-sensitised solar cells with titanium dioxide thin films based on screen-printing technique
Fabrication and tests of a three-dimensional microsupercapacitor using SU-8 photoresist as the separator
Microstructure and piezoelectric properties of AlN thin films grown on stainless steel for the application of vibration energy harvesting
Development of microelectromechanical systems electromagnetic vibration energy scavengers with a nonlinear electroplated nickel spring
Micro cobalt electrodes for detection of total phosphorus in water
Absolute micro pressure measurements based on a high-overload-resistance sensor
Nickel–chromium alloy piezoresistive pressure sensor using eutectic bonding
Polymer MEMS pressure sensor arrays for fish-like underwater sensing applications
Flexible capacitive sensor encapsulating liquids as dielectric with a largely deformable polymer membrane
Micro electrochemical sensor with copper nanoclusters for nitrate determination in freshwaters
Towards optimised wireless Love wave biosensor with high sensitivity
Finite element analysis of microneedle insertion into skin
Minimising plasma irradiation area by micronozzle device towards single-cell treatment
Flow-type microbial chip for screening of a single bacterium
Interaction between microspheres of collagen/biphasic calcium phosphate and mesenchymal stem cells
Non-planar surface bonding with spray-coated SU-8 as adhesive layer
Micro fabrication of lead-free (K,Na)NbO3 piezoelectric thin films by dry etching
Characteristic investigation of a static micro polymerase chain reaction chip based on in situ electrochemical detection
Micro-machined resonant out-of-plane accelerometer with a differential structure fabricated by silicon-on-insulator–MEMS technology
Regulating parameters of electromagnetic micromachined vibrating ring gyroscope by feedback control
G-band rectangular waveguide filter fabricated using deep reactive ion etching and bonding processes
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- Author(s): J. Descarpentries ; D. Buttard ; L. Dupré ; T. Gorisse
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1241 –1245
- DOI: 10.1049/mnl.2012.0754
- Type: Article
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Electrodeposition of copper in cylindrical pores of a nanoporous alumina template is investigated. An electrochemical deposition mode with pulsed current is used in an aqueous copper sulphate solution. The evolution of the deposition quality in terms of height, shape and filling ratio is analysed against several parameters: the intensity, duration and number of pulses. Systematic observations and analyses using scanning electron microscopy are carried out. Statistical and quantitative treatment has been performed. A high filling ratio of more than 90%, the height control and a conformal shape of the copper nanoparticles have been achieved. - Author(s): Zuo-Yang Zhong ; Su-Juan Liu ; Wen-Ming Zhang ; Guang Meng ; Chang-Ming Cheng
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1246 –1250
- DOI: 10.1049/mnl.2012.0670
- Type: Article
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Nanomechanical (NEMS) resonators made from carbon nanotubes (CNTs) have emerged as ubiquitous devices for use in mass detection. Many oscillation behaviours of CNT mass detection have been theoretically studied by the continuum elastic model, albeit their performance is limited by deleterious effects of mechanical damping. Reported are the support-induced losses in generic mechanical resonators because of the tunnelling of mesoscopic phonons between the CNT and its supports. After formulating the problem, the resulting differential equations are solved analytically using the method of multiple scales, and a closed form solution is obtained. The results reveal that the Young’s modulus, density and geometric parameters of the CNT not only influence the resonant frequency shift and the system stiffness, but also affect the system vibration amplitude. Moreover, the effect of the supports material on the oscillation is discussed. Also, the phonon-tunnelling dissipation for dynamics of CNT mass detection is highlighted. - Author(s): Hongmei Xu ; Rui Li ; Jinpeng Shen ; Guangcheng Yang ; Chonghua Pei
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1251 –1255
- DOI: 10.1049/mnl.2012.0728
- Type: Article
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Metastable intermolecular composite (MIC) has been widely touted for their potential to fulfil the objectives of high energetic materials and nanotechnology. In this study, nanofibrous CuO/Al MIC films on the silicon substrate were successfully synthesised by evaporating and depositing Al on the surface of nanoporous CuO films, which were prepared by calcinating polyvinylpyrrolidone (PVP)/Cu(NO3)2 films obtained through the electrospinning process. The structures and energetic properties of the nanofibrous CuO/Al MIC films were characterised by a scanning electron microscope, X-ray diffraction, Fourier transform-infrared spectroscopy, TGA–DSC and open-air combustion experiments. The results revealed that the electrospinning process was an effective way to prepare energetic films. The optimised calcination temperature of the PVP/Cu(NO3)2 composite films was 500°C, and the starting reaction temperature of the nanoporous CuO/Al MIC film was 532°C. - Author(s): C.M. Nguyen ; O. Thumthan ; C. Huang ; U. Tata ; Y. Hao ; J.-C. Chiao
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1256 –1259
- DOI: 10.1049/mnl.2012.0730
- Type: Article
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High aspect ratio iridium (IV) oxide nanorods have been successfully grown on a copper thin film by a chemical co-precipitation method. A porous anodised aluminium oxide (AAO) template was implemented to assist the growth of the well aligned and densely packed iridium oxide (IrO2) nanostructures. Nanorods with an aspect ratio of 22 can be synthesised within 45 min. X-ray diffraction measurement unveiled the crucial role of the AAO template in the orientation-aligned growth of IrO2 nanorods along the [110] crystallography direction. The large surface area of IrO2 nanostructures exhibiting a high capacitive property can be utilised in supercapacitors or sensing applications. Owing to the simpler fabrication processes, IrO2 nanorods can be mass produced in a short period of time. - Author(s): Shijie Wu ; Wenjing Lu ; Qi Kang ; Dazhong Shen ; Dawei Pan
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1260 –1263
- DOI: 10.1049/mnl.2012.0768
- Type: Article
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A report is presented on a novel and effective route to synthesise bismuth nanoparticles (BiNPs) on the electrode surface, which was carried out by ion-exchange in Nafion film coated on the electrode surface and subsequent electrochemical reduction of Bi3+ ions to BiNPs on site. The properties of the resulting BiNPs modified electrode were investigated by scanning electron microscopy, an energy dispersive X-ray microanalyser and electrochemistry. Almost 10 nm BiNPs were decorated in the matrix of Nafion film and showed excellent electrochemical activity. The BiNPs modified electrode has been successfully used for determination of Pb2+ by anodic stripping voltammetry with a linear range of 1.0–90 nM. The detection limit is 0.3 nM with 5 min accumulation. The practical application of this modified electrode was carried out for determination of Pb2+ in water samples and the results were consistent with those obtained by inductively coupled plasma-mass spectrometry. - Author(s): Li-Yuan Chai ; Wan-Ting Yu ; Li-Yuan Zhang ; Hai-Ying Wang
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1264 –1266
- DOI: 10.1049/mnl.2012.0656
- Type: Article
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Hollow poly(m-phenylenediamine) (PmPD) microparticles were successfully synthesised with chemically oxidative polymerisation through rapidly mixing the persulphate oxidant solution with m-phenylenediamine solution at room temperature. In a further experiment, Na2CO3 was used to create a CO2 bubble to facilitate the formation of hollow PmPD microparticles. The morphology and molecular structure of the products were characterised with scanning electron microscopy, transmission electron microscopy and Fourier transmission infrared spectroscopy. The results showed that the PmPD possesses a mouth-like cave when synthesised without Na2CO3. More interestingly, using Na2CO3, the cave number and shape of PmPD microparticles change. The PmPD synthesised with or without Na2CO3 has similar functional groups but different oxidation state. - Author(s): Wang Li ; Xiaomei Zheng ; Fagen Li ; Jun Wang
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1267 –1269
- DOI: 10.1049/mnl.2012.0718
- Type: Article
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Uniform rare-earth gadolinium oxide (Gd2O3) hollow spheres with tunable shell thickness have been successfully fabricated in the presence of SiO2 as templates via a urea-based homogeneous precipitation method. The synthesis is a mild, low-cost and convenient method without any catalysts. By varying the times of the precipitation procedure, the shell thickness can be successfully controlled within the 20–55 nm range. The thickness increase of each coating might be ∼10 nm. The as-synthesised product was identified from X-ray diffraction pattern, scanning electron microscopy and energy dispersive X-ray. The prepared hollow Gd2O3 spheres with tunable shell thickness and fluorescence property have the potential to be used for drug delivery, fluorescent labelling and controlled release applications. - Author(s): Bingjun Yu ; Xiaoying Li ; Hanshan Dong ; Linmao Qian
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1270 –1273
- DOI: 10.1049/mnl.2012.0521
- Type: Article
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Through nanoindentation and nanoscratch tests, it is demonstrated that friction-induced protrusive nanostructures (or hillocks) showed good mechanical behaviour. At the maximum indentation depth of 2 nm, the elastic modulus of the hillocks on the silicon/quartz surface was only 5.3%/14.8% lower than that measured on their substrates. After scratching under a contact pressure of 10.3 GPa on silicon hillocks or 7.2 GPa on quartz hillocks, no surface damage was observed on the scratched area. Hence, the friction-induced hillocks can withstand typical contact in dynamic MEMS. Even though the scratch depths were much larger than the height of the detected hillocks, no peeling-off scar or surface crack could be detected beside the grooves on the hillocks, which indicated that the hillocks bonded strongly to their substrates. Further analysis revealed that the strength of the friction-induced hillocks was strongly dependent on the friction-induced process. The hillock produced at high sliding speed can lead to a high elastic modulus. Transmission electron microscope detection showed that the deformed silicon matrix formed chiefly at high sliding speed can enhance the elastic modulus of the hillocks. As a comparison, the amorphous silicon layer formed mainly at low sliding speed can reduce the elastic modulus of the hillocks. - Author(s): Kun Wang ; Bin He ; Run-Jie Shen
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1274 –1277
- DOI: 10.1049/mnl.2012.0683
- Type: Article
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Biological adhesive pads of some reptiles and insects, such as tree frogs and grasshoppers, are covered with planar microstructures and have strong and stable adhesive ability on both wet and dry substrates. These adhesion forces do not mainly come from van-der-Waals force but wet adhesion. In this study, the influence of substrates' surface roughness on the wet adhesion of man-made adhesive pads inspired by tree frog toe pads is investigated experimentally. Biomimetic polydimethylsiloxane adhesive pads with planar hexagon microstructures with a microchannels width of 10 µm are fabricated by combining electroforming with soft lithography. Experiments of wet adhesive force between the pads and sandpaper slices with different average surface roughness are carried out at various preloads. Results show that the rougher surface leads to the decrement of wet adhesion force. It is also observed that if the microcosmic profile height of the substrates is near or less than the width of microchannels in the biomimetic adhesive pads, the microstructures and preloads can increase significantly the wet adhesive force, otherwise the microstructures and preloads do not contribute indistinctively. The experimental results can be explained by analysing the relation between the solid contact area and the area with a liquid bridge. - Author(s): Ying Huang ; Qiufen Wang ; Yan Wang
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1278 –1281
- DOI: 10.1049/mnl.2012.0714
- Type: Article
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Polypyrrole-coated Li2SnO3 (Li2SnO3/PPy) nanocomposite has been prepared by a micro emulsion polymerisation. The X-ray diffraction and transmission electron microscopy analysis reveals that the Li2SnO3 crystal particles with a uniform and block structure are coated by PPy with amorphous behaviour. The particle sizes of Li2SnO3 are in the range from 40 to 50 nm with clear lattice fringes. The Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis reveals the surface structure and the binding nature of the elements of Li2SnO3/PPy composite. Electrochemical measurement suggests that Li2SnO3/PPy nanocomposite exhibits better cycling properties and lower initial irreversible capacities than Li2SnO3 as anode materials for lithium-ion batteries. At a current density of 60 mA/g in the voltage about 0.01–2.0 V, the first discharge–charge capacities of Li2SnO3/PPy are 1482.2 and 892.1 mAh/g, whereas they are 2104.5 and 1417.0 mAh/g for Li2SnO3. The retention capacity of Li2SnO3/PPy (560.1 mAh/g) is higher than that of Li2SnO3 (510.2 mAh/g) after 50 cycles. - Author(s): Guoqiang Han ; Yuqin Chen ; Bingwei He
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1282 –1284
- DOI: 10.1049/mnl.2012.0842
- Type: Article
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An atomic force microscopy (AFM) image of a surface is a convolution of the tip geometry and sample features. It is important to develop tip characterisers and estimate the tip shape for a more accurate AFM image. With the traditional characterisers with special microstructures it is difficult to accurately determine tip shape because of their dimensional uncertainty. Combined with tip blind reconstruction algorithms, some nanomaterials with arrayed nanostructures are often used to estimate the AFM tip morphology. However, the blind reconstruction algorithms are sensitive to image noise. To solve such problems, the porous anodic alumina (PAA) film with well-ordered porous nanostructures was fabricated and used as a new tip characteriser. By setting the appropriate scanning routine and scanning mode, the two-dimensional and three-dimensional tip morphology was accurately calculated. PAA film as the AFM tip characteriser can effectively reduce the influence of AFM image noise and sample-dimensional uncertainty of tip blind estimation results, especially avoiding tip wear and damage. - Author(s): Rongxian Zhang ; Haiying Cui ; Xiaofei Yang ; Hua Tang ; Heng Liu ; Yang Li
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1285 –1288
- DOI: 10.1049/mnl.2012.0765
- Type: Article
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Rod-like nanosized silver tungstate (Ag2WO4) was synthesised via a facile hydrothermal method and characterised by field emission scanning electron microscopy, X-ray diffraction, Raman spectroscopy and electron spin resonance spectroscopy. Under ultraviolet (UV) light, nearly complete degradation of rhodamine B (RhB) was observed in Ag2WO4 suspension after irradiation for 60 min, around 15% RhB was absorbed in the dark. However, more than 60% of methyl blue was absorbed in the dark and the rest was observed to be completely degraded upon UV light irradiation for 10 min. The formed superoxide (O2−.) and hydroxyl (·OH) radicals, as well as photoinduced holes were considered to be the dominant active species in the photocatalytic process. - Author(s): Tao Zhang ; Jingjun Jin ; Chunzhi Yang ; Huayi Peng ; Li Lai ; Junyong Han ; Ming Zheng
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1289 –1291
- DOI: 10.1049/mnl.2012.0808
- Type: Article
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Quantum dots (QDs) as new fluorescent nanomaterial, have shown potential application for in vivo imaging technology in the past decades, whereas the toxicity of QDs hinders the development of this technology for in vivo application. Here, the authors report a facile, rapid and reproducible route to synthesise protein conjugated CdSe QDs by microwave irradiation. Ribonuclease A protein could serve as a bio-molecular template in the formation of CdSe clusters, and it endows the CdSe QDs with high stability and low bio-toxicity in aqueous medium. The final products were characterised by UV–vis absorption, photoluminescence spectra, X-ray powder diffraction and high-resolution transmission electron microscopy. Furthermore, MTT assay has shown that it has high biocompatibility and low toxicity in vitro. - Author(s): Haiying Cui ; Xiaofei Yang ; Jieling Qin ; Hua Tang ; Heng Liu ; Yang Li
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1292 –1295
- DOI: 10.1049/mnl.2012.0674
- Type: Article
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In this study, an amino acid, glutamine, has been employed as the modifier in the hydrothermal synthesis of rod-like hydroxyapatite (HAp) nanoparticles. X-ray diffractometer results confirm the formation of a typical HAp phase without impurities and microscopic results indicate that the morphology and size of the as-prepared products could be controlled by adjusting the pH value of the hydrothermal system. Owing to a variety of amino acids and characteristics of as-synthesised nano-sized HAp, the findings may have implications in the large-scale controllable synthesis of well-defined HAp nanomaterials; it may also provide a general facile and low-cost method for the preparation of uniform nanostructured HAp by utilising biomolecules as modifiers. - Author(s): P. Sharma ; P.J. Babu ; U. Bora
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1296 –1299
- DOI: 10.1049/mnl.2012.0684
- Type: Article
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A report is presented on the synthesis of gold nanoparticles (AuNPs) using aqueous extract of Sapindus mukorossi, a traditional medicinal plant in India. UV-visible spectroscopy analysis indicated the successful formation of AuNPs. The synthesised AuNPs were characterised with different techniques such as transmission electron microscopy (TEM), Fourier transforms infrared (FTIR) spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX). TEM experiments showed that AuNPs were predominantly spherical and hexagonal in shape with an average size of 7.3 nm. FTIR spectroscopy revealed that AuNPs were functionalised with biomolecules that have primary amine group (–NH2), carbonyl group, –OH groups and other stabilising functional groups. Thermo gravimetric analysis (TGA) revealed the weight loss (13%) of AuNPs. FTIR, TGA and EDX together confirmed the presence of biomolecules bounded on the AuNPs. Cytotoxicity of the AuNPs was tested on two human cancer cell lines, HeLa and A549 and found to be non-toxic, which thus proved their biocompatibility. - Author(s): M. Salavati-Niasari ; M. Esmaeili-Zare ; A. Sobhani
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1300 –1304
- DOI: 10.1049/mnl.2012.0709
- Type: Article
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A convenient sonochemical process for the preparation of HgSe nanoparticles by using Hg(CH3COO)2 and SeCl4 in the presence of hydrazine as reductant agent has been discovered. Three capping agents have been used that include triethanolamine, sodium dodecyl sulfate and thioglycolic acid. The products were characterised by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, photoluminescence spectroscopy (PL) and X-ray energy dispersive spectroscopy. The effects of the capping agent, ultrasonic power, temperature and reaction time on the morphology, particle size and phase of nano-sized HgSe products have been investigated. HgSe microspheres are obtained after 15 min of sonocation. With increasing aging time, the microspheres were broken and agglomerated nanoparticles are formed. With increasing temperature smaller sizes of HgSe are obtained. The particles coalesce and turn into bulk structures in the absence of sonocation. The as-prepared HgSe shows a blue-shifted emission in the PL spectrum, compared with the bulk sample, which confirms the larger variation of particle sizes. - Author(s): Enling Li ; Xuhui Cheng ; Danna Zhao ; Rui Xu ; Meng Xi ; Zhen Cui ; Tao Zhao
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1305 –1307
- DOI: 10.1049/mnl.2012.0829
- Type: Article
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Oriented gallium nitride (GaN) nanowires grown on Pt-coated Si (1 1 1) substrates, were synthesised using the chemical vapour deposition method under different Ga sources. The characteristics of the grown GaN nanowires were investigated using scanning electron microscopy and X-ray diffraction, which found that the as-synthesised GaN nanowires of the three samples are of different orientation, and all displayed hexagonal wurtzite structures of GaN crystals. The electron field-emission properties of the three samples of GaN nanowires showed a low turn-on field of 4.5, 5.5 and 6.2 V/µm, respectively, and field enhancement factors of 1337, 2948 and 2599, respectively. - Author(s): Win-Jin Chang and Haw-Long Lee
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1308 –1312
- DOI: 10.1049/mnl.2012.0612
- Type: Article
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The vibration behaviour of a simply supported carbon nanotube is studied using the non-local viscoelasticity theory, including the thermal and foundation effects. The complex frequency in closed-form expression is obtained in terms of the damping ratio. The frequency is associated with the non-local parameter, damping coefficient and thermal and foundation effects. According to the analysis, the natural frequency significantly decreases by increasing the damping coefficient, especially at a small non-local parameter. The critical damping coefficient decreases when the thermal effect is considered in the analysis, especially at a higher non-local parameter. However, the situation is reversed when the foundation effect is considered. In addition, by increasing the non-local parameter, the mode shape increases. However, the mode shape apparently decreases by increasing the damping coefficient. - Author(s): Xiao-Xiao Yan ; Jing-Quan Liu ; Shui-Dong Jiang ; Bin Yang ; Chun-Sheng Yang
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1313 –1315
- DOI: 10.1049/mnl.2012.0633
- Type: Article
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Metal microneedles are fabricated by the process of cutting and electrochemical corrosion. The fabricated microneedles are 400 µm in length, 700 µm in space and have sharp tapered tips. In a force test, these microneedles could penetrate an artificial skin and a rat's skin well and safely. In a vitro transdermal drug delivery test, the amount of the permeated flux of calcein and of the bovine serum albumin through the treated rat skin increased by 35 and six times than that on the intact skin, respectively. - Author(s): Raziyeh Ghelich ; Mansoor Keyanpour Rad ; Amir Ali Yuzbashi ; Zahra Khakpour
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1316 –1319
- DOI: 10.1049/mnl.2012.0767
- Type: Article
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Ni–Ce0.8Gd0.2O1.9 composite is an efficient anode electrode in solid oxide fuel cells. In this study, for the first time, the remarkably simple technique of electrospinning has been employed to prepare the corresponding nanofibres. For this purpose, the cation complexation method was applied for preparing a sol containing Ni, Gd and Ce nitrates as the precursors and citric acid as the chelating agent. Gel formation was accomplished by heating the sol at 80°C and then a polyvinyl alcohol solution was added to maintain proper viscosity of the electrospinning solution. The spun nanofibres were calcined at different temperatures to obtain the NiO-GDC nanofibrous material. Calcined nanofibres were characterised by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, a energy dispersive spectrometer, transmission electron microscopy and Brunauer-Emmett-Teller techniques. It was found that the size of crystalline nanofibres were in the range of 90 nm. Specific surface area is found to be 145 m2/g for the calcined nanofibre at 900°C. - Author(s): Jian Jin ; Xudi Wang ; Xin Li ; Xiaojun Li ; Si Di
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1320 –1323
- DOI: 10.1049/mnl.2012.0775
- Type: Article
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Polymer-based nano/microfluidic devices are becoming increasingly important for biological applications and fluidic control. Reported is a new etching method for the fabrication of nano/microfluidic channels based on SU-8 using AZ1350 as a sacrificial resist. In contrast to all the previous fabrication routes, this etching method is suitable for fabricating the channel with dimensions ranging from micrometres to nanometres. By this route, the most critical step is to prevent the two mixed photoresists and this problem is solved by sputtering a thin layer of SiO2. Furthermore, this is a size-controlled nanochannel fabrication method because the size of the channel is only dependent on the sacrificial layer structure whose size could be controlled by the oxygen plasma process. In addition, the developing etching speed is measured and some methods to accelerate the developing etching rate are proposed. This novel process is simple and inexpensive for mass nano/microchannel manufacturing, which could have wide applications in biomedical and fluidic transport systems. - Author(s): Wei Si ; Jingyuan Yu ; Miaoyan Huang ; Chao Ding ; Hong Gao
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1324 –1327
- DOI: 10.1049/mnl.2012.0832
- Type: Article
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The cube and hexagonal prism zinc oxide (ZnO) microstructures have been controllably synthesised by the facile liquid precipitation method by using sodium dodecyl benzene sulphonate and cetyltrimethyl ammonium bromide as surfactant separately. The probable formation mechanism is also proposed based on the experimental results. The photoluminescence characterisation of cube and hexagonal prism ZnO structures exhibited a strong blue emission at 470 nm and the emission intensity of the cube ZnO improved ∼60% more than the hexagonal prism ZnO. The photocatalytic activities of the cube and hexagonal prism ZnO were investigated by methyl orange, rhodamine B and fuchsine acid as a model organic compound under ultraviolet light irradiation. The results show that the photocatalytic activity of the cube ZnO is superior to that of the hexagonal prism ZnO when the above three dyes were used. It is suggested that photocatalytic activities are improved by changing the morphologies of ZnO crystals. - Author(s): Rui Fan ; Xiangping Deng ; Xiaoyou Yuan
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1328 –1332
- DOI: 10.1049/mnl.2012.0753
- Type: Article
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The amorphous NdCoxOy nanowire arrays have been successfully fabricated using anodic aluminium oxide (AAO) membrane templates by suction filtration at subatmospheric pressure (SFSP). The morphology and chemical composition of NdCoxOy nanowires were characterised by a scanning electron microscope, a transmission electron microscope, selected area electron diffraction, X-ray diffraction and energy dispersive spectra, respectively. The results reveal that there are plenty of NdCoxOy nanowires in the nanopores of the AAO template, and the NdCoxOy nanowires are all uniform in diameter. The concentration of reactants, the subatmospheric pressure and the co-precipitation time played an important role in the formation of NdCoxOy nanowires. The NdCoxOy nanowires with different diameters were fabricated with AAO of different nanopore sizes, the luminescence spectrum of NdCoxOy nanowires were doped with different Eu3+ concentrations and different morphological luminescence intensities of NdCoxOy:Eu3+ indicate that the method of SFSP is a feasible and controllable approach. The hysteresis loops of the Nd2O3, NdCoxOy and NdLaxOy nanowire arrays were carried out by a vibrating sample magnetometer (VSM); the magnetic behaviour of rare earth oxide can be modulated by doping the magnetic cobalt (Co) and non-magnetic Lanthanum (La) elements. - Author(s): P. Dhiman ; K.M. Batoo ; R.K. Kotnala ; M. Singh
- Source: Micro & Nano Letters, Volume 7, Issue 12, p. 1333 –1335
- DOI: 10.1049/mnl.2012.0862
- Type: Article
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A report is presented on the structural, electrical, optical and magnetic properties of Fe-doped ZnO nanoparticles synthesised by the solution combustion technique. Structural characterisation by X-ray diffraction confirmed the phase purity of the samples. Surface morphology studied by scanning electron microscope revealed a cubic-type shape of grains. Energy dispersive X-ray spectroscopy analysis confirmed the elemental composition. Less value of DC electrical conductivity and increased bandgap for doped ZnO from UV–Vis studies confirmed change in the defect chemistry of the ZnO matrix. However, varied synthesis process results in ferromagnetic behaviour for doped ZnO nanoparticles.
Highly conformal deposition of copper nanocylinders uniformly electrodeposited in nanoporous alumina template for ordered catalytic applications
Dynamics of carbon nanotubes mass detection involving phonon-tunnelling dissipation
Preparation and characterisation of nanofibrous CuO/Al metastable intermolecular composite films
Chemical bath method to grow precipitated nanorods of iridium oxide on alumina membranes
Site synthesis of bismuth nanoparticles for electrochemical determination of lead
Facile and large-scale synthesis of poly(m-phenylenediamine) microparticles with interesting hollow morphology
Facile synthetic route to hollow gadolinium oxide spheres with tunable thickness
Mechanical performance of friction-induced protrusive nanostructures on monocrystalline silicon and quartz
Influence of surface roughness on wet adhesion of biomimetic adhesive pads with planar microstructures
Preparation and electrochemical characterisation of polypyrrole-coated Li2SnO3 anode materials for lithium-ion batteries
Blind reconstruction of atomic force microscopy tip morphology by using porous anodic alumina membrane
Facile hydrothermal synthesis and photocatalytic activity of rod-like nanosized silver tungstate
Microwave synthesis CdSe quantum dot clusters via ribonuclease A protein
Hydrothermal synthesis and characterisation of glutamine-modified rod-like hydroxyapatite nanoparticles
Sapindus mukorossi aqueous fruit extract as reducing, capping and dispersing agents in synthesis of gold nanoparticles
Cubic HgSe nanoparticles: sonochemical synthesis and characterisation
Synthesis and field-emission properties of oriented GaN nanowires
Vibration analysis of viscoelastic carbon nanotubes
Tapered metal microneedles fabricated by the hybrid process of mechanical dicing and electrochemical corrosion for drug delivery
Preparation and characterisation of NiO–Ce0.8Gd0.2O1.9 composite nanofibres via electrospinning
Nano/microchannel fabrication based on SU-8 using sacrificial resist etching method
Controllable synthesis and photocatalytic activities of cube and hexagonal prism ZnO
Controllable synthesis of NdCoxOy nanowire arrays and magnetic behaviour
Fe-doped ZnO nanoparticles synthesised by solution combustion method
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