X-Ray Radiation Sensing Properties of ZnS Thin Film:A Study on the Effect of Annealing

Chemically synthesized ZnS thin film is found to be a good x-ray radiation sensor. We report the effect of annealing on the x-ray radiation detection sensitivity of a ZnS thin film synthesized by a chemical bath deposition technique. The chemically synthesized ZnS films are annealed at 333, 363 and 393K for 1 h. Structural analyses show that the lattice defects in the films decrease with annealing. Further, the band gap is also found to decrease from 3.38 to 3.21 eV after annealing at 393K. Current-voltage characteristics of the films are studied under dark and x-ray irradiation conditions. Due to the decrease of lattice defects and band gap, the conductivity under dark conditions is found to increase from 2.06 × 10^-6 to 1.69 × 10^-5 S/em, while that under x-ray irradiation increases from 4.13 × 10^-5 to 5.28 ×10^-5 S/cm. On the other hand, the x-ray radiation detection sensitivity of the films is found to decrease with annealing. This decrease of detection sensitivity is attributed to the decrease of the band gap as well as some structural and surface morphological changes occurring after annealing.

Syntheses, Structures, and Photoluminescent Properties of Two 2D Coordination Polymers Based on 1,3-Di(2,4-dicarboxyphenyl) Benzene and 1,3-Di(4-pyridyl)propane

Two new 2D coordination polymers, [Zn（HL）（Hbpp）]n （1） mid [Cd（HL）（Hbpp）（H2O）]n （2） （H4L = 1,3-di（2,4-dicarboxyphenyl） benzene, bpp = 1,3-di（4-pyridyl）propane）, have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis, elemental analysis, TGA and 1R spectroscopy. Complex 1 crystallizes in monoclinic, space group P21/n, with a = 13.1031（6）, b = 14.7315（7）, c = 15.0041（7） A, β = 91.202（1）°, V= 2895.6（2） A3, Dc = 1.532 g/cm3, Mr = 667.97, F（000） = 1376.0, μ = 0.909 mm-1, Z = 4, the final R = 0.0481 and wR = 0.1304 for 7027 observed reflections with 1 〉 2a（/）. Complex 2 also belongs to the monoclinic space group P2Jn, with a = 13.6326（4）, b = 14.6432（4）, c = 14.9395（5）A, β = 93.132（1）°, V= 2977.84（16） A3, D, = 1.613 g/cm3, ）14,. = 1445.98, F（000） = 733.0,/1 = 0.794 mm-1, Z = 2, the final R = 0.0283 and wR = 0.0784 for 7230 observed reflections with I 〉 2σ（I）. Both complexes 1 and 2 form 2D net structures, which are further linked to form 3D supramolecular net structures via intermolecular hydrogen bonds and aromatic π-π stacking interactions.

Investigation of europium(Ⅲ)-doped ZnS for immunoassay

Biofunctional europium（Ⅲ）-doped ZnS（ZnS：Eu） nanocrystals are prepared by a sol–gel method. The characteristic luminescence of ZnS：Eu is used as a probe signal to realize sensitive immunoassay. The luminescence intensity of the Eu^（3＋） in the ZnS matrix shows strong concentration dependence, and the optimal doping concentration is 4%. However,the emission wavelengths of the ZnS：Eu nanocrystals are not dependent on doping concentration nor the temperature（from 100 K to 300 K）. Our results show that these features allow for reliable immunoassay. Human immunoglobulin, used as a target analyte, is captured by antibody modified ZnS：Eu probe and is finally enriched on gold substrate for detection.High specificity of the assay is demonstrated by control experiments. The linear detection range is 10 nM –800 nM, and the detection limit is about 9.6 nM.

Effect of Zn Substitution on Magnetic Properties of CuFe_2O_4： a High-Temperature Series Expansions Study

The magnetic properties of spinel ferrites Cu_（1-x）Zn_xFe_2O_4 are studied using high-temperature series expansions combined with the Padé approximates. The exchange interactions, inter and intra-sublattices J_（AA）, J_（BB） and J_（AB） are obtained using a probability distribution law. The critical exponent associated with the magnetic susceptibility is obtained.

Effect of Pre-heating Temperature on Structural and Optical Properties of Sol-gel Derived Zn_(0.8)Cd_(0.2)O Thin Films

Zn_（0.8）Cd_（0.2）O thin films prepared using the spin-coating method were investigated. X-ray diffraction, scanning electron microscopy, and UV-Vis spectrophotometry were employed to illustrate the effects of the pre-heating temperature on the crystalline structure, surface morphology and transmission spectra of Zn_（0.8）Cd_（0.2）O thin films. When the thin films were pre-heated at 150 ℃, polycrystalline Zn O thin films were obtained. When the thin films were pre-heated at temperatures of 200 ℃ or higher, preferential growth of Zn O nanocrystals along the c-axis was observed. Transmission spectra showed that thin films with high transmission in the visible light range were prepared and effective bandgap energies of these thin films decreased from 3.19 e V to 3.08 e V when the pre-heating temperature increased from 150 ℃ to 300 ℃.

Improving mechanical properties of age-hardenable Mg–6Zn–4Al–1Sn alloy processed by double-aging treatment

Microstructure and mechanical properties of a new high-strength Mg–6 Zn–4 Al–1 Sn alloy were investigated. Microstructure of the as-cast Mg alloy exhibited partially divorced characteristics. The dendritic structure of the Mg–6 Zn–4 Al alloy was significantly refined with the addition of 1%（in weight） Sn, but Mg2 Sn phases were not formed. In addition, an icosahedral quasi-crystal phase was formed in the as-cast Mg–6 Zn–4 Al–1 Sn alloy. It was found that after the double-aging treatment through two different heat treatments on the Mg–6 Zn–4 Al–1 Sn alloy, the precipitates were finer and far more densely dispersed in the matrix compared with single-aged counterpart, resulting in a significant improvement in tensile strength with yield strength, ultimate tensile strength and elongation of 175 MPa, 335 MPa and 11%,respectively.

ZnS/Bacterial Cellulose/Epoxy Resin(ZnS/BC/E56) Nanocomposites with Good Transparency and Flexibility

ZnS/bacterial cellulose/epoxy resin （ZnS/BC/E56） nanocomposites with good transparency and flexibil-ity were prepared and characterized. When the precursor Zn^2＋ concentrations were not more than I wt%, the size of the introduced ZnS nanoparticles was smaller than 50 nm and the distribution was homo-geneous within the composites. Under the condition, outstanding transmittance more than 70g in the visible light was obtained. By incorporation of ZnS nanoparticles with excellent thermo-optic stability to the composites, the thermo-optic coefficient was obviously increased from -361 × 10^-6 to -310 × 10^-6K^-1. The good flexibility, optical and mechanical properties endow the nanocomposites potential applica- tions in the flexible optoelectronic materials.

Preparation and properties of W–Cu–Zn alloy with low W–W contiguity

The W–Cu–Zn alloy with a-brass matrix and low W–W contiguity was prepared by method of electroless copper plating combined with spark plasma sintering（SPS） method.The effects of process and parameters on the microstructure and mechanical properties of the alloy were investigated.The W–Cu–Zn alloy with a relative density of 96 % and a W–W contiguity of about 10 % was prepared by original fine tungsten particles combined with wet mixing method and SPS solid-state sintering method at 800℃ for 10 min.The microstructure analysis shows that Cu–Zn matrix consists of nano-sized a-brass grains,and the main composition is Cu3Zn electride.The nano-sized Cu was coated on the surface of tungsten particles by electroless copper plating method,and the fairly low consolidation temperature and short solid-state sintering time result in the nano-sized matrix phase.The dynamic compressive strength of the W–Cu–Zn alloy achieves to1000 MPa,but the alloy shows poor ductility due to the formation of the hard and brittle Cu3Zn electrides.The fine-grain strengthening and the solution strengthening of the Cu–Zn matrix phase are responsible for the high Vickers microhardness of about 300 MPa for W–Cu–Zn alloy.

Zinc(Ⅱ) coordination architectures based on 5-(1H-tetrazol-1-yl)-isophthalic acid:Synthesis,structures and luminescent properties

With different pyridine-analogs as auxiliary ligands,three novel Zn（Ⅱ） complexes（1-3） based on 5-（1Htetrazol-1-yl） isophthalic acid（H_2L） have been synthesized and structurally characterized.Single crystal X-ray diffraction analyses of complexes 1-3 show the presence of tetrazolyl group,as well as the coordination behavior of the auxiliary ligands as critical factors determining the structures of such Zn（Ⅱ）-carboxyIate coordination architectures.In addition,the resulting complexes all exhibit luminescence properties in the solid state at room temperature.

In Vitro Evaluation of the Feasibility of Commercial Zn Alloys as Biodegradable Metals

In this work, three widely used commercial Zn alloys （ZA4-1, ZA4-3, ZA6-1 ） were purchased and pre- pared by hot extrusion at 200℃. The microstructure, mechanical properties, corrosion behaviors, biocompatibility and hemocompatibility of Zn alloys were studied with pure Zn as control, Commercial Zn alloys demonstrated increased strength and superb elongation compared with pure Zn. Accelerated corrosion rates and uniform corrosion morphologies were observed in terms of commercial Zn alloys due to galvanic effects between Zn matrix and α-Al phases. 100% extracts of ZA4-1 and ZA6-1 alloys showed mild cytotoxicity while 50% extracts of all samples displayed good biocompatibility. Retardant cell cycle and inhibited stress fibers expression were observed induced by high concentration of Zn^2＋ releasing during corrosion. The hemolysis ratios of Zn alloys were lower than 1% while the adhered platelets showed slightly activated morphologies. In general, commercial Zn alloys possess promising mechanical properties, appropriate corrosion rates, significantly improved biocompatibility and good hemocompatibility in comparison to pure Zn. It is feasible to develop biodegradable metals based on commercial Zn alloys.

Processing of a Novel Zn Alloy Micro-Tube for Biodegradable Vascular Stent Application

In recent years, zinc based alloys as a new biodegradable metal material aroused intensive interests. However, the processing of Zn alloys micro-tubes （named slender-diameter and thin-walled tubes） is very difficult due to their HCP crystal structure and unfavorable mechanical properties. This study aimed to develop a novel technique to produce micro-tube of Zn alloy with good performance for biodegrad- able vascular stent application. In the present work, a processing method that combined drilling, cold rolling and optimized drawing was proposed to produce the novel Zn-5Mg-1Fe （wt%） alloy micro- tubes. The micro-tube with outer diameter of 2.5 mm and thickness of 130 μm was fabricated by this method and its dimension errors are within 10 μm. The micro-tube exhibits a fine and homogeneous microstructure, and the ultimate tensile strength and ductility are more than 220 MPa and 20% respectively. In addition, the micro-tube and stents of Zn alloy exhibit superior in vitro corrosion and expansion performance. It could be concluded that the novel Zn alloy micro-tube fabricated by above method might be a promising candidate material for biodegradable stent.

Studies on morphology, electrical and optical characteristics of Al-doped ZnO thin films grown by atomic layer deposition

Al doped ZnO（AZO） films deposited on glass substrates through the atomic layer deposition（ALD）technique are investigated with various temperatures from 100 to 250 °C and different Zn ： Al cycle ratios from20 ： 0 to 20 ： 3. Surface morphology, structure, optical and electrical properties of obtained AZO films are studied in detail. The Al composition of the AZO films is varied by controlling the ratio of Zn ： Al. We achieve an excellent AZO thin film with a resistivity of 2.14 × 10^（-3）Ω·cm and high optical transmittance deposited at 150 °C with20 ： 2 Zn ： Al cycle ratio. This kind of AZO thin films exhibit great potential for optoelectronics device application.