Hydrogen and Ozone SAW Based Gas Sensors with RF Magnetron Sputtered InO_x and Electron Beam Evaporated SiN_y

Layered Surface Acoustic Wave (SAW) devices with an InO_x/SiN_u/36°YX LiTaO_3 structure were investigated for sensing low concentrations of hydrogen (H_2) and ozone (O_3) at different operating temperatures.The sensor consists of a 1μm thick silicon nitride (SiN_y) intermediate layer deposited by electron beam evaporation on a 36°Y-cut X-propagating piezoelectric lithium tantalate (LiTaO_3) substrate and a 100 nm thin indium oxide (InO_x) sensing layer deposited by R.F.magnetron sputtering.The device fabrication is described and the performance of the sensor is analyzed in terms of response magnitude as a function of operating temperature.Large frequency shifts of 360 kHz for 600μg/g of H_2 and 92 kHz for 40 ng/g O_3 were recorded.In addition,the surface morphology of the deposited films were investigated by Atomic Force Microscopy (AFM) and the chemical composition by X-Ray Photoelectron Spectroscopy (XPS) to correlate gas-sensing behavior to structural characteristics of the thin film.

Computational interaction analysis of organophosphorus pesticides with different metabolic proteins in humans

Pesticides have the potential to leave harmful effects on humans, animals, other living organisms, and the environment. Several human metabolic proteins inhibited after exposure to organophosphorus pesticides absorbed through the skin, inhalation, eyes and oral mucosa, are most important targets for this interaction study. The crystal structure of five different proteins, PDBIDs： 3LII, 3NXU, 4GTU, 2XJ1 and 1YXA in Homo sapiens （H. sapiens）, interact with organophosphorus pesticides at the molecular level. The 3-D structures were found to be of good quality and validated through PROCHECK, ERRAT and ProSA servers. The results show that the binding energy is maximum -45.21 relative units of cytochrome P450 protein with phosmet pesticide. In terms of H-bonding, methyl parathion and parathion with acetylcholinesterase protein, parathion, methylparathion and phosmet with protein kinase C show the highest interaction. We conclude that these organophosphorus pesticides are more toxic and inhibit enzymatic activity by interrupting the metabolic pathways in H. sapiens.

Three dimensional structure prediction and proton nuclear magnetic resonance analysis of toxic pesticides in human blood plasma

The purpose of this study was to investigate the nuclear magnetic resonance （NMR） assignments of hydrolyzed products extracted from human blood plasma. The correlations between chemical, functional and structural prop- erties of highly toxic pesticides were investigated using the PreADME analysis. We observed that toxic pesticides possessed higher molecular weight and, more hydrogen bond donors and acceptors when compared with less toxic pesticides. The occurrence of functional groups and structural properties was analyzed using ~H-NMR. The ~H- NMR spectra of the phosphomethoxy class of pesticides were characterized by methyl resonances at 3.7-3.9 ppm （8） with the coupling constants of 11-16 Hz （Je-cns）. In phosphoethoxy pesticides, the methyl resonance was about 1.4 ppm （8） with the coupling constant of 10 Hz （Je-cH2） and the methylene resonances was 4.2-4.4 ppm （8） with the coupling constant of 0.8 Hz （Jp-cH3）, respectively. Our study shows that the values of four parameters such as chemical shift, coupling constant, integration and relaxation time correlated with the concentration of toxic pesticides, and can be used to characterise the proton groups in the molecular structures of toxic pesticides.

Microwave Synthesis, Characterization and Photocatalytic Properties of SnO2 Nanoparticles

In the present endeavour, SnO2 nanoparticles (NPs) were synthesized using microwave method. Synthesized SnO2 NPs were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrscopy (EDS) to find their structure, morphology and elemental composition. SnO2 NPs were of spherical morphology having crystallite size of 35.42 nm as obtained from Scherrer’s formula using most intense peak of XRD. Synthesized NPs were used for photodegradation of melthylene blue (MB) dye under UV light. The SnO2 NPs ware found to have photodegradation efficiency and apparent rate constant of 55.97% and 2.149 × 10_2 respectively.

Effects of V and Cr Addition on the Structural and Sensing Properties of Titania

We have comparatively studied the addition of Cr and V in titania.Cr and V content were changed by means of insets placed in the Ti target.Structural,compositional and electrical analyses of different series of thin films,made by XRF, XRD,are presented.Electrical characterization not only showed that Cr doped layers were very sensitive to ethanol within a useful range for applications,but also allowed to verify that the electrical behaviour is dependent on the structure of film. Finally,the Cr and V concentrations that gives the best results in terms of sensing performances has been determined and a correlation between structural and electrical measurement has been evidenced.

Structural,optical and antimicrobial properties of pure and Agdoped ZnO nanostructures

In the present work,zinc oxide(ZnO)and silver(Ag)doped ZnO nanostructures are synthesized using a hydrothermal method.Structural quality of the products is attested using X-ray diffraction,which confirms the hexagonal wurtzite struc-ture of pure ZnO and Ag-doped ZnO nanostructures.XRD further confirms the crystallite orientation along the c-axis,(101)plane.The field emission scanning electron microscope study reveals the change in shape of the synthesized ZnO particles from hexagonal nanoparticles to needle-shaped nanostructures for 3 wt%Ag-doped ZnO.The optical band gaps and lattice strain of nanostructures is increased significantly with the increase of doping concentration of Ag in ZnO nanostructure.The anti-microbial activity of synthesized nanostructures has been evaluated against the gram-positive human pathogenic bacteria,Staphylococcus aureus via an agarose gel diffusion test.The maximum value of zone of inhibition(22 mm)is achieved for 3 wt%Ag-doped ZnO nanostructure and it clearly demonstrates the remarkable antibacterial activity.

Investigation on Temperature Sensing of Nanostructured Zinc Oxide Synthesized via Oxalate Route

A detailed study is reported of the synthesis and characterization of n- type ZnO nanomaterial and its application as temperature sensor. The ZnO nanomaterial has been synthesized through pyrolysis of the oxalate produced by a conventional precipitation method. It is synthesized by flash heating the oxalate at 450°C for 15 min. Pellet of this material was prepared and used as a sensing element. The variations in resistance of sensing pellet at different temperatures were recorded. The relative resistance was decreased linearly with increasing temperatures over the range, 120°C - 260°C. The activation energy of ZnO calculated from Arrhenius plot was found 1.12 eV. Temperature response in terms of the relative variation, ΔR, of sensor resistance to a given temperature was measured. Scanning electron micrograph of the sensing element has been studied. Pellet of the ZnO is comprised of nanorods of varying diameters and different lengths. Diameter of ZnO nanorods varies from 75 to 300 nm. X-ray diffraction pattern of the sensing element reveal their nano-crystalline nature. Optical characterization of the sensing material was carried out by UV-visible spectrophotometer. By UV-Vis spectra, the estimated value of band gap of ZnO was found 4.7 eV.

Distributed polymer optical fiber sensors:a review and outlook

Aging degradation and seismic damage of civil infrastructures have become a serious issue for society,and one promising technology for monitoring their conditions is optical fiber sensing.Glass optical fibers have been predominantly used for the past several decades to develop fiber sensors,but currently polymer or plastic optical fibers(POFs)have also been used extensively to develop advanced fiber sensors because of their unique features,such as high flexibility,large breakage strain,and impact resistance.This review focuses on recently developed distributed and quasi-distributed POF-based sensing techniques based on Rayleigh scattering,Brillouin scattering,and fiber Bragg gratings.

Emerging trends in self-healable nanomaterials for triboelectric nanogenerators:A comprehensive review and roadmap

A thorough analysis of triboelectric nanogenerators (TENGs) that make use of self-healable nanomaterials is presented in this review. These TENGs have shown promise as independent energy sources that do not require an external power source to function. TENGs are developing into a viable choice for powering numerous applications as low-power electronics technology advances. Despite having less power than conventional energy sources, TENGs do not directly compete with these. TENGs, on the other hand, provide unique opportunities for future self-powered systems and might encourage advancements in energy and sensor technologies. Examining the many approaches used to improve nanogenerators by employing materials with shape memory and self-healable characteristics is the main goal of this review. The findings of this comprehensive review provide valuable information on the advancements and possibilities of TENGs, which opens the way for further research and advancement in this field. The discussion of life cycle evaluations of TENGs provides details on how well they perform in terms of the environment and identifies potential improvement areas. Additionally, the cost-effectiveness, social acceptability, and regulatory implications of self-healing TENGs are examined, as well as their economic and societal ramifications.

穿透型金刚石X射线位置灵敏探测器及其在同步辐射光束线上的应用

X射线位置灵敏探测器是同步辐射光束线上不可缺少的重要部件,由它所提供的光束位置和强度的实时数据是监测光束线运行状态的重要依据。为适应对高亮度同步辐射光束的测量需要,我们成功地研制了一套穿透型金刚石位置灵敏探测器,并在上海光源生物大分子结构晶体学束线(BL17U1)上对其性能进行了测定。测量数据表明,在整块探测器(2.5 mm×2.5 mm)上均具有极好的线性响应,探测器的信/噪比(S/N)>5×103,位置分辨能力为s=(136±11)nm,光强强度的测量精度和线性度均<0.1%,能满足第三代同步辐射和第四代光源(自由电子激光)束线上对光强、光斑位置及其运动轨迹的监测需求,是束线诊断的重要设备。

A method for modeling and deciphering the persistent photoconductance and long-term charge storage of ZnO nanorod arrays

The controllability of persistent photoconductance （PPC） and charge/energy storage of ZnO nanorod arrays （NRAs） were demonstrated experimentally by tuning the nanorod diameter. The dependency of the ZnO NRAs＇ photoelectric characteristics on the nanorod diameter suggests that the Debye length and photon penetration depth in ZnO could spatially partition a standalone nanorod into three different photoelectric functional regions （PFRs）. Theoretically, a series of rate functions was employed to describe the different extrinsic/intrinsic carrier photogeneration/recombination dynamic sub-processes occurring in the different PFRs, associated with oxygen chemisorption/photodesorption, oxygen vacancy photoionization, and electron trapping by photoionized oxygen vacancies. On the basis of the coupled contributions of these different dynamic sub-processes in the photoelectric properties of the ZnO NRAs, a thorough-process photoelectric dynamic model （TPDM） was proposed using the simultaneous rate functions. Through solving the rate functions, the corresponding analytical equations could be employed to simulate the time-resolved PPC spectra of the ZnO NRAs, and then the quantitative parameters extracted to decipher the PPC and charge/energy storage mechanisms in the ZnO NRAs. In this way, the TPDM model provided a numerical-analytical method to quantitatively evaluate the photoelectric properties of ZnO NRA-based devices. Additionally, the TPDM model revealed how the different photoinduced carrier dynamics in the different PFRs could play functional roles in different optoelectronic applications, e.g., photodetectors, photocatalysts, solar cells and optical nonvolatile memories, and thus it illuminated a practical approach for the design of ZnO NRA-based devices via optimization of the modularized spatial configuration of the PFRs.

Two-dimensional Dirac plasmon-polaritons in graphene,3D topological insulator and hybrid systems

Collective oscillations of massless particles in two-dimensional(2D)Dirac materials offer an innovative route toward implementing atomically thin devices based on low-energy quasiparticle interactions.Strong confinement of nearfield distribution on the 2D surface is essential to demonstrate extraordinary optoelectronic functions,providing means to shape the spectral response at the mid-infrared(IR)wavelength.Although the dynamic polarization from the linear response theory has successfully accounted for a range of experimental observations,a unified perspective was stll elusive,connecting the state-of-the-art developments based on the 2D Dirac plasmon-polaritons.Here,we review recent works on graphene and three-dimensional(3D)topological insulator(TI)plasmon-polariton,where the mid-IR and terahertz(THz)radiation experiences prominent confinement into a deep-subwavelength scale in a novel optoelectronic structure.After presenting general light-matter interactions between 2D Dirac plasmon and subwavelength quasiparticle excitations,we introduce various experimental techniques to couple the plasmonpolaritons with electromagnetic radiations.Electrical and optical controls over the plasmonic excitations reveal the hybridized plasmon modes in graphene and 3D Tl,demonstrating an intense near-field interaction of 2D Dirac plasmon within the highly-compressed volume.These findings can further be applied to invent optoelectronic biomolecular sensors,atomically thin photodetectors,and laser-driven light sources.

Design of an experimental platform to investigate the effects of audible sounds on plant growth

An experimental platform was developed to investigate the effects of audible sound(20 Hz to 20 MHz)on plant growth promotion,which included a microcontroller-based embedded system for audible sound adjustment and analysis.The direct digital frequency synthesis(DDFS)method was used to generate various waveforms of sound in the platform.Soundproof glass and mufflers were used to reduce background noise.The developed system was tested on various plants,including hydroponic tomatoes,celery and mung bean.The testing results showed that the developed platform could produce pure tone and mixing audible sound with high stability and accuracy,make octave analysis of the sound under experimental environments,and the background noise in the testing chamber of the platform was lower than 55 dB(A)when the compression engine was working.The developed experimental platform has a great potential on facilitating scientific research on acoustic biology effects on plants and collecting real-time experimental data.

Improved Method for the Total Synthesis of Azaperone and Investigation of Its Electrochemical Behavior in Aqueous Solution

Azaperone,with anti-anxiety and anti-aggressive activities used in veterinary medicine,is a member of the butyrophenone class.It is ordinarily utilized for a wide range of indications,such as sedation,obstetrics,and anesthesia.In this research,an improved synthetic route is presented for azaperone using a phase-transfer catalyst(PTC).In general,it was synthesized as a dopamine antagonist in four steps.The bis(2-chloroethyl)amine intermediate is easily obtained after the conversion of the alcohol groups into the chloride leaving group using thionyl chloride(95%yields).The alkylation of commercially available 2-amino pyridine in the presence of PTC was then carried out,giving 1-(pyridin-2-yl)piperazine with 75%yield.1-(Pyridin-2-yl)piperazine was finally alkylated using 4-chloro-1-(4-fluorophenyl)butan-1-one to achieve azaperone with 60%yield.The butyrophenone intermediate was obtained via the Friedel-Crafts reaction of fluorobenzene with 4-chlorobutyryl chloride in the presence of AlCl3.High efficiency,gentle reaction conditions,and fast and simple procedure are the advantages of this method.Also,the electrochemical oxidation behaviour of azaperone was investigated using cyclic and differential pulse voltammetry techniques.Cyclic voltammetric studies indicated an irreversible process for azaperone electro-oxidation with a peak potential of 0.78 V in a phosphate buffer solution(pH=7.0)vs.Ag/AgCl(saturated KCl)electrode.The value of the peak current vs.the azaperone concentration was enhanced linearly in the range of 10―70μmol/L,and the detection limit was found to be 3.33μmol/L.