ZnO/SnO_2,SnO_2/ZnO UPF复合膜的制备及气敏特性研究

用直流气体放电活化反应蒸发沉积技术在普通玻璃基片上制备了ZnO／SnO2及SnO2／ZnO超微粒子（UPF）双层复合薄膜。样品经扫描电子显微镜（SEM）和X射线衍射仪分析，结论为超微粒子的复合薄膜。同时提出了最佳制备工艺。气敏测试结果表明：ZnO／SnO2及SnO2／ZnOUPF复合膜较单层ZnO及SnO2UPF表现出优良的选择性，其灵敏度和最佳工作温度也得到相应的改善。     

Recovery of Cu(II) and Cd(II) by a chelating resin containing aspartate groups

A chelating resin, crosslinked poly(glycidyl methacrylate-aspartic acid) (PASP), was synthesized by anchoring sodium aspartate to crosslinked poly(glycidyl methacrylate) for the recovery of Cu2+ and Cd2+ from aqueous solutions. The resin was characterized by Fourier transform infrared spectroscopy, scanning electron microscope and mass balance. In non-competitive conditions, the adsorptions tended toward equilibrium at 60 min and the equilibrium adsorption capacities were 1.40 and 1.28 mmol/gPASP for Cu2+ and Cd2+, respectively. The adsorption isothermals of the metal ions by PASP followed the Freundlich isotherm. Adsorption of Cu2+ was affected slightly in the presence of NaNO3 (0-0.3M) but the uptake of Cd2+ decreased significantly in the same condition. Except pH> or =4.0, the adsorption capacity of each metal ion decreased with lowering of solution pH. The reusability of PASP in adsorptions was investigated for five successive adsorption-desorption operations. When the pH of Cu2+/Cd2+ mixture was 2 or 2.5, the competitive adsorption tests confirmed this resin had good adsorption selectivity for Cu2+ with the coexistence of Cd2+.     

石英和BK7玻璃的离子束刻蚀特性研究

石英和BK7玻璃是常用的光学材料和微系统材料.用Ar作为工作气体对石英和BK7玻璃及其掩模材料AZ1350的离子束刻蚀特性进行了研究,分析了离子能量、离子束流密度和离子束入射角等几种因素对刻蚀速率和选择比的影响,结合相关理论得到了相应的刻蚀速率拟合方程.AFM测量结果表明刻蚀工艺对材料的低损伤.由于与光刻胶的刻蚀选择比较低,随着石英和BK7玻璃刻蚀深度的增加,图形转移精度下降.因此提高刻蚀选择比是获得高分辨率图形的前提.     

New polymer-supported ion-complexing agents: design, preparation and metal ion affinities of immobilized ligands

Polymer-supported reagents are comprised of crosslinked polymer networks that have been modified with ligands capable of selective metal ion complexation. Applications of these polymers are in environmental remediation, ion chromatography, sensor technology, and hydrometallurgy. Bifunctional polymers with diphosphonate/sulfonate ligands have a high selectivity for actinide ions. The distribution coefficient for the uranyl ion from 1 M nitric acid is 70,000, compared to 900 for the monophosphonate/sulfonate polymer and 200 for the sulfonic acid ion-exchange resin. A bifunctional trihexyl/triethylammonium polymer has a high affinity and selectivity for pertechnetate and perchlorate anions from groundwater. In one example, its distribution coefficient for perchlorate ions in the presence of competing anions is 3,300,000, compared to 203,180 for a commercially available anion-exchange resin. Polystyrene modified with N-methyl-D-glucamine ligands is capable of selectively complexing arsenate from groundwater. It complexes 99% of the arsenate present in a solution of 100 mg/L arsenate with 560 mg/L sulfate ions. Its selectivity is retained even in the presence of 400 mg/L phosphate. There is no affinity for arsenate above pH 9, allowing for the polymer to be regenerated with moderate alkali solution. In studies aimed at developing a Hg(II)-selective resin, simple amine resins were found to have a high Hg(II) affinity and that affinity is dependent upon the solution pH and the counterion.     

ICP刻蚀技术在808nm激光器中的应用

主要分析了不同工艺参数对于刻蚀图形的影响，包括刻蚀侧壁角度，刻蚀表面平整度，选择比，侧向钻蚀等几个方面，及ICP刻蚀对激光器性能的影响，通过对翔蚀图形的控制，使2寸片内均匀性〈±5％，侧壁角达到79°～81°。     

Nanocrystalline chemically modified CdIn2O4 thick films for H2S gas sensor

CdIn₂O₄ sensor with high sensitivity and excellent selectivity for H₂S gas was synthesized by using sol-gel technique. Structural, electrical and gas sensing properties of doped and undoped CdIn₂O₄ thick films were studied. XRD revealed the single-phase polycrystalline nature of the synthesized CdIn₂O₄ nanomaterials. Since the resistance change of a sensing material is the measure of its response, selectivity and sensitivity was found to be enhanced by doping different concentrations of cobalt in CdIn₂O₄ thick films. The sensor exhibits high response and selectivity toward H₂S for 10 wt.% Co doped CdIn₂O₄ thick films. The current-voltage characteristics of 10 wt.% Co doped CdIn₂O₄ calcined at 650 °C shows one order increase in current with change in the bias voltage at an operating temperature of 200 °C for 1000 ppm H₂S gas.     

Synthesis of SnO2 hollow microspheres from ultrasonic atomization and their role in hydrogen sensing

Nanostructured SnO₂ hollow microspheres were synthesized using ultrasonic atomization technique. It is interesting that hollow microspheres could be prepared from ultrasonic atomization technique without any aid of template and surfactant. X-ray powder diffraction (XRD) confirmed the material to be SnO₂ having tetragonal structure. Average crystallite size calculated from X-ray diffractogram using Scherer's equation was found to be 8.45 nm. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to study the microscopic study of fine powder particles. Powder consists of hollow microspheres of average diameter of 0.58 μm as well as nanoparticles of average diameter of 6 nm. The sensors fabricated from such powder show high hydrogen (1000 ppm) response (S = 2379) under the optimized experimental conditions. Sensor performance merits, such as, high hydrogen response, high hydrogen selectivity, short response time (2 s) and quick recovery time (15 s) may be due to both nanocrystallites and hollow microspheres associated in SnO₂ sensing material. The dramatic change in gas response was explained by the rapid diffusion of the target gas through the nano-porous structure of SnO₂ hollow microspheres.     

An efficient strategy for the partial oxidation of methane into methanol over POM-immobilized MOF catalysts under ambient conditions

One of the scientific obstacles in the direct conversion of methane to methanol lies in how to improve product selectivity. A dark photocatalysis mode that decouples solar energy in the dark may effectively alleviate this challenge. Herein, a range of composites had been prepared in which Fe-BTC was employed as the gas enrichment unit, while phosphotungstic acid (PTA) acted mainly as an electron storage within the framework. The modified reaction system allowed for the achievement of methanol yields up to 968 μmol·g_cat⁻¹·h⁻¹ under ambient conditions. Besides extrinsic factors, such as a gentle reaction environment and avoidance of the oxidation reactions between photogenerated holes and alcohols, we also demonstrated through in situ EPR measurements that the introduced PTA effectively regulated •OH radicals and suppressed their further reaction with methanol. Moreover, the strategy demonstrated its universality by effectively enhancing the performance of other POM-immobilized MOF composites. This work opens a new path for the efficient and targeted conversion of inert methane to methanol.     

Cu-doped CoOOH activates peroxymonosulfate to generate high-valent cobalt-oxo species to degrade organic pollutants in saline environments

A Cu doped CoOOH-activated peroxymonosulfate (CoCu10/PMS) process was developed to enable the generation of Co(IV)=O for efficient oxidation of pollutants in saline water. The formation of Co(IV)=O was demonstrated through phenylmethyl sulfoxide (PMSO) probe and ¹⁸O-isotope-labeling tests. CoCu10 was synthesized using a simple and scalable co-precipitation method, enabling efficient synthesis at laboratory scale for large quantities (gram level). Cu doping increased the surface hydroxyl density of CoOOH, thereby improving its activation performance. Coordinating with PMS through surface hydroxyls, CoCu10 formed catalyst-PMS complexes, then donated electrons to induce heterolytic cleavage of O–O bonds in complexes, resulting in the formation of Co(IV)=O. At a concentration of 0.2 g/L catalyst and 0.2 mM PMS, 97.7% of tetracycline was degraded within 10 min. CoCu10 maintained stable performance over eight cycles. Thanks to Co(IV)=O, the CoCu10/PMS system efficiently operates under different concentrations of Cl⁻, HCO₃⁻, NO₃⁻, SO₄²⁻, H₂PO₄⁻ and mixed salt.