The supported base/zeolite catalysts are prepared and applied in the catalytic Michael additions of acrylonitrile with monohydric alcohols to 3-alkoxypropanenitriles in a solvent-free system. The catalysts are characterised by powder X-ray diffraction. For the Michael addition of methanol to acrylonitrile, 10% K₂CO₃/ZSM-5 shows the best activity with 98.3 mol% conversion of acrylonitrile and 100% selectivity of 3-methoxypropanenitrile. The recyclable stability of the 10% K₂CO₃/ZSM-5 catalyst is confirmed. The effects of various parameters are investigated systematically. By comparing the catalytic activity of anion-exchanged CO₃ ²⁻-resin for the titled addition, a feasible reaction route is proposed.

Mounting the atomic force microscope (AFM) probe on the gripper of the robotic nanoscale manipulators system enables the combination of the AFM and scanning electron microscope (SEM). The AFM–SEM-based method of determining Hamaker constant for carbon nanotube (CNT) and AFM cantilever in the vacuum condition of SEM, which is completed through a robotic nanoscale manipulators system, is presented for the first time. During Hamaker constant determining experiment, the elastic force is measured utilising integrated AFM–SEM imaging technique through detecting the deflection of AFM cantilever that actually equals van der Waals adhesion force. The van der Waals attraction force between CNT and AFM cantilever is calculated through the modelling of a cylindrical nanotube and a flat gold-coated surface. The experiment results indicate that Hamaker's constant measured are comparable to typical values published by previous researchers, being of the order of 100 zJ, which indicates that the present approach is valid and reliable.

A truly simple, reproducible, and environmentally friendly non-vacuum synthesis method for synthesising of carbon-free Cu₂ZnSnSe₄ (CZTSe) absorber layer has been presented. The stannite CZTSe nanoparticles with an average size of about 20 nm distributions were fabricated by an ambient mechanical milling procedure using Cu₂Se, Zn, Sn, elemental selenium powders as raw materials and non-toxic ethanol as solvent. The compact CZTSe thin films were formed via an annealing treatment under Ar/Se atmosphere using rapid thermal processing. The optical properties of the obtained CZTSe thin films are the absorption coefficient (α) exceeding 10⁴ cm⁻¹ and E _g of 0.91 eV. The electrical properties of the CZTSe thin films indicate p-type semiconductor behaviour. The photovoltaic properties of this solar cell are power conversion efficiency of 0.18%.

The optical microstructure on the roller surface is the key for manufacturing microstructures on optical film. In this context, the fabrication of optical microstructures on the cylindrical roller surface is more difficult than that on the planar surface. This Letter starts with a machinability of microstructure arrays on a cylindrical surface, and studies the restriction influences of the tool geometry and process parameters on the characteristics of the microstructure. Then a suitable flexible hinge holder for the fast tool servo is designed based on finite element analysis, and the influential factors to the machining precision of microstructure arrays are investigated. Finally, a machining test of spherical arrays on an aluminium cylindrical surface is carried out, and the high quality of the microstructure indicates that the proposed method is appropriate for the fabrication of optical microstructures.

Scientists use biological procedures as ecofriendly and cost-effective routes to synthesis nanoparticles and nanomaterials. In this work, the biological attitude was aimed at the production of nanoparticles by Haplophyllum obtusifolium watery extract. Several procedures used to describe fabricated nanoparticles are transmission electron microscopy, ultraviolet–visible (UV–vis) spectrometry, Fourier transform infrared spectroscopy, and X-ray diffraction. UV–vis technique indicated a sharp peak in area 416 nm and transmission electron microscopy pictures show that the shape of the nanoparticles is spherical and the mean diameter of the synthesised nanoparticle is 13 nm. The silver and silver oxide-nanoparticles (Ag/Ag₂O-NPs) exhibited antimicrobial properties against positive/negative infective bacteria for instance Staphylococcus aureus/Pseudomonas aeruginosa, Escherichia coli. The biosynthesised nanoparticles show anticancer activity against liver cancer cell (HepG2) which depend on time and concentrations. Also, the synthesised Ag/Ag₂O-NPs act as a green catalyst because of accelerated degradation of stable and organic dye. Consequences established this protocol as easy, fast, nontoxic and alternative conventional physico-chemical approache.

Natural clay sepiolite with high specific surface area and unique porous structure exhibits great potential for application in the fields of water treatment. However, the adsorption methods suffer from some drawbacks, such as the production of toxic sludge and secondary pollution. Electrospinning technology has been widely employed to fabricate porous composite fibres. Thus, the authors design a high-efficiency electrospun polyurethane/sepiolite membrane that can remove heavy metal ions from drinking water. This kind of sepiolite-based membrane not only exhibits high absorption capacity of Cr, Cd, As and Mn, but also offers several advantages such as minimising the risk of secondary pollution. Sepiolite-based membrane shows great potential for applications including urgent drinking-water treatment, field survival and disaster rescue.

Pure zeolite X was synthesised by a facile microwave-assisted two-step approach using high silicon fly ash, industrial-grade reagents and tap water. First, a microwave heating method was conducted to extract silicon and the extract process was completed in 20 min, which was more effective. Then, a microwave approach was used to synthesis zeolite X. The whole analysis process is <2 h. The composition, phase structure, morphology, particle size distribution, specific surface areas and adsorption of heavy metal ions were evaluated comprehensively. The results show that single phase zeolite X with octahedral structure and an average diameter of 1.10 μm is obtained, and the Brunauer–Emmett–Teller surface area is 583.22 m²/g. Especially, the adsorption of Cu²⁺ and Zn²⁺ are as high as 81.33 and 67.21 mg/g, respectively. It can be concluded that the Letter provides a facile and fast method utilising high silicon fly ash to synthetise zeolite X, which is an excellent adsorbent to remove heavy metal ions.

This Letter reports the multilevel resistive switching characteristics of bipolar bi-layer nanodevice made of Ag/Al₂O₃(10 nm)/ZnO (5 nm)/fluorine-doped tin oxide for the first time, exhibiting five distinguishable resistive states including both high resistance state (HRS) and low resistance state (LRS). Among five distinct memory states, three resistive states are attained with RESET voltages and two are attained with SET voltages. The distinguishable resistive levels obtained with RESET voltages 2.3, 3.0 and 3.8 V are 1300, 2700 and 4320 Ω, respectively, whereas two stable resistive levels attained with SET voltages 0.8 and 1.70 V are 3000 and 100 Ω, respectively. Moreover, the proposed device excels in its R _off/R _on ratio of 354 obtained with HRS/LRS at −1.4 V as well as the ratio of intermediate states IRS1, IRS2, IRS3 to HRS becomes 15, 04 and 27, respectively. Further, the conduction mechanism as well as the switching mechanism are demonstrated. Finally, the cycle-to-cycle as well as device-to-device variability in device characteristics and statistical distribution of their resistance levels are also analysed and report that devices in the sample are also exhibiting stable multilevel capability.

Alcohol has a potential health risk to human health, so it is important to realise the rapid detection of alcohols. Based on this, the nano Na₂Mg(CO₃)₂ was prepared by a simple hydrothermal method to establish a cataluminescence (CTL) gas sensor for alcohols. The Na₂Mg(CO₃)₂with highly purified quality was characterised by scanning electron microscope, energy dispersive spectroscopy and the powder X-ray diffraction. The results show that the nano Na₂Mg(CO₃)₂ is a peony-like substance with a large surface area, which will be beneficial to produce ultra-weak chemiluminescence reaction between the detector and the material. The peony-like Na₂Mg(CO₃)₂ has good CTL response to alcohols (methanol, ethanol, n-propanol and n-butanol), showing high selectivity. The response time of Na₂Mg(CO₃)₂ for four alcohols is between 1 and 2 s, which indicate that the material has the advantage of rapid response. The limit of detection of four alcohols defined as 3 N/S is about 7.91, 4.75, 6.69 and 8.10 mg/l, respectively. The optimum reaction conditions of the gas sensor based on nano Na₂Mg(CO₃)₂ are mild and this nanomaterial can be used for alcohol detection.

In the present investigation, the authors have adopted a simple and economical method for the synthesis of bright green photoluminescent carbon nanodots (CNDs) from tender coconut water via acid-assisted ultrasonic route. Tender coconut water is used as a less expensive and eco-friendly carbon precursor to produce well-dispersed CNDs possessing a hybrid structural behaviour of both nanocrystalline and amorphous carbon phases. The monodispersed CNDs with spherical morphology and particle size (4 ± 1 nm) were confirmed with the aid of high-resolution transmission electron microscopy. The functional groups attached to CNDs are held responsible for the fluorescence nature and mono-dispersion that were assessed using Fourier transform infrared spectroscopy. The green fluorescence nature of CNDs was evaluated at a maximum emission at 510 nm with an excitation wavelength of 450 nm, using ultraviolet–visible absorption spectrum and photoluminescence spectra. The CNDs with a carbon core and chemical groups over their surface exhibited a fluorescence quantum yield of 60.18%. The stability, low-cost precursor, rapid reaction and uniform dispersion without chemical functionalisation makes these CNDs synthesised from tender coconut water more advantageous than other sources. This research mainly emphasis on synthesis and characterisation of CNDs with a detailed mechanism for CND formation.

The undoped titanium dioxide (TiO₂) and zinc-doped TiO₂ gels were prepared by sol–gel method. The nano-TiO₂ powders were prepared by controlling the sintering temperature. The phase compositions of the sintered samples were analysed by powder X-ray diffraction; the microstructure was analysed by high-resolution transmission electron microscope; the photocatalytic activity was analysed by photochemical reactions instrument. The combined action of Zn²⁺ doping and heat treatment on phase transformation and photocatalytic performance of TiO₂ were analysed. The results show that, when the Zn ion doping amount is within 1–5 mol%, it promotes the conversion of anatase to rutile transition as the presence of ZnTiO_3. The photocatalytic performance of TiO₂ sintered at 700°C is better than sintered at 400°C.

In this Letter, an uncooled monolithic resonant terahertz (THz) thermal detector using a standard 55 nm CMOS technology is presented. The detector is constructed by the integration of a loop antenna loaded with a polysilicon resistor and a proportional to absolute temperature sensor, which is used as a temperature-sensitive device. An overview of the design considerations, as well as the comparatively better characterisation results are demonstrated in detail. A high-temperature coefficient of voltage (TCV_D) of 10.11 mV/°C, a maximum responsivity of 48.67 V/W, and a minimum noise equivalent power of 1.22 μW/Hz^0.5 for the thermal detector are measured at the optimal operating point of 2.58 THz.

In the present work, regenerated cellulose films with different pore sizes were prepared using cellulose, which can control the synthesis reaction of nano-ZnO and thus regulate its morphology. The results show that with 0, 4, and 8 g of cellulose applied, average pore sizes of samples increased from 7.0 nm to 14.4 and 20.1 nm, respectively. When no cellulose was used, only large Zn₅(OH)₈Cl₂·H₂O (ZHC) flakes were prepared. Long ZnO nano-sheets and ZHC flakes with a mass fraction of 0.51 and 0.33, respectively, were prepared by adding 4 g cellulose; and ZnO nano-sheets with a mass fraction of 0.73, with 0.04 ZHC, were synthesised while using 8 g cellulose. The results reveal that the addition of cellulose can improve the average pore diameter of films and enhance the reaction rate of ZnO, resulting in the formation of ZnO nano-sheets/regenerated cellulose films.

Copper oxide/manganese dioxide (CuO/MnO₂) nanocomposites were prepared by a facile microwave-assisted synthesis method in an ordinary household microwave oven and used for electrochemical supercapacitor. The nanocomposites were characterised by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. Electrochemical results demonstrate that CuO/MnO₂ nanocomposites have better capacitance performance than pure CuO material. The CuO/MnO₂ nanocomposites have a high specific capacitance of 499.0 F/g at a current density of 0.5 A/g in 6 M KOH electrolyte. In addition, an asymmetric supercapacitor with activated carbon as a negative electrode and CuO/MnO₂ nanocomposite as a positive electrode was also successfully prepared. This asymmetric device exhibits a high energy density of 32.07 Wh/kg at a power density of 375.02 W/kg and fairly good cycling stability.

The synthesis of mesoporous γ-Fe₂O₃ nanoparticles by eco-friendly one-step microwave irradiation method in ambient atmospheres without surfactants as described in this Letter. Characterisation of synthesised nanoparticles was performed by X-ray diffraction, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller surface area & pore volume analyser, field emission scanning electron microscopy, high-resolution transmission electron microscopy, and superconducting quantum interference device. The adsorption behaviour of nanoparticles towards methyl orange, an azo dye, was examined in aqueous solutions under various operational conditions like pH, temperature, contact time, and adsorbent weight. Results suggest that as-synthesised γ-Fe₂O₃ nanoparticles are mesoporous and superparamagnetic at room temperature. Some characteristics of γ-Fe₂O₃ nanoparticles, for example, saturation magnetisation, pore diameters, specific surface areas, and pore volumes are 72.0 emu g⁻¹, 7.11 nm, 189.35 m² g⁻¹, and 0.52 cm³ g⁻¹, respectively. The experimental data of adsorption study fitted with the Langmuir isotherm model and maximum adsorption capacity is 403.23 mg g⁻¹. The reusability of the γ-Fe₂O₃ nanomaterials was examined, and it can be recycled for ten cycles. In sum, this simple eco-friendly synthesis method of magnetic mesoporous adsorbent is suitable for large scale production without any template or surfactant or inert atmosphere.

With the advancement and development of science and technology, the detection role of small-scale robot has become increasingly prominent, especially for environmental detection in hazardous situations such as explosion and fire. In this study, to realise the detection of carbon monoxide gas in hazardous locations, a flexible carbon monoxide sensor consisting of polyimide, interdigital electrode, and composite film is proposed and designed, which has the advantages of simple structure, high sensitivity, good flexibility, and low cost. For the interdigital electrode, the distance between the electrodes and the width of the electrode is both 50 μm, and the sizes of the polyimide substrate and the electrode area are 1.5 × 4 cm² and 1 × 1 cm², respectively. The composite film is made by mixing single-walled carbon nanotubes and platinum powders. The test results show that the sensitivity of the sensor is 0.0201 Ω/ppm in the range of 0–100 ppm at room temperature with a linear fit of 94.63%.

Rheumatoid arthritis (RA) is an autoimmune disease that principally attacks synovial joints. RA also cause inflammation in the joints and associated regions. There is an unmet medical need for RA as well as for the targetted drug delivery of anti-rheumatic drugs to improve its efficacy at a much lower doses while decreasing its side effects. Hence, in this Letter, the authors report the development and characterisation of glucosamine sulphate magnetic nanoparticles for magnetically targetted RA chemotherapy.

Tellurene, a single layer of tellurium, is a new emerging 2D material and a possible candidate for the post-silicon era. It has anisotropic carrier effective mass in zigzag and armchair directions. Therefore, the study of the anisotropic performance of tellurene FETs is a timely topic. In this work, the authors study the transport mechanism and performance metrics of tellurene n-channel and p-channel transistors using a quantum simulation. Heavy carrier mass in the armchair direction effectively blocks the tunnelling current and the transport is governed by thermionic emission over the potential barrier. On the other hand, lighter carrier mass in the zigzag direction results in a mixed tunnelling and thermionic transport mechanism. The n-channel transistor has an on-state current of 894 μA/μm, a sub-threshold slope of 62 mV/dec, a 9.27 mS/μm transconductance, a 0.129 ps delay, and a 0.046 fJ/μm dynamic power loss. The p-channel metrics are, respectively, 852 μA/μm, 62 mV/dec, 9.24 mS/μm, 0.117 ps, and 0.040 fJ/μm. Both the transistors comply with the International Technology Roadmap for Semiconductors 2026 low operating power device requirements.

Traditional bio-inks are mostly limited in application due to their low-mechanical strength or complex cross-linking curing methods. In this study, a nanocomposite hydrogel bio-ink [gelatin–alginate–montmorillonite (GT–AT–MMT)] for 3D bioprinting is designed based on the thermo-sensitive properties of GT, the advantages of ionic crosslinking of sodium AT, and the shear thinning and toughening mechanism of nano-MMT. The 3D printing of the bio-ink with variable AT content is optimised, and the tensile, compressive, and creep properties of the 3D printed structure are studied. Results show that GT–AT–MMT bio-ink has good printability, and its mechanical properties are enhanced with increased AT content. The tensile modulus of the GT–4% AT–MMT sample can reach 0.533 MPa, which has a minimum creep deformation of 0.311 mm under the same load condition. Therefore, GT–AT–MMT bio-ink provides a new possibility for the development of 3D bioprinting, which will offer many opportunities in fields such as tissue engineering, drug delivery, and regeneration medicine.

A design modification to an existing border termination for active-edge planar radiation detectors is proposed, which enables a dead area reduction and a much larger breakdown voltage to be achieved, with a minor increase in the fabrication complexity. ‘Technology Computer-Aided Design’ simulations allowed the device performance of different variants of the proposed structure to be investigated also in comparison with the existing one. Among considered designs, the new border terminations with 2(3) guard rings, featuring a dead area at the edge of ∼90(120) μm, can withstand more than 375(500) V for all oxide charge density values up to 3 × 10¹² cm⁻². These characteristics make them appealing for X-ray imaging applications at free-electron laser facilities.