Phosphorylation of NiAl-layered double hydroxide nanosheets as a novel cocatalyst for photocatalytic hydrogen evolution

In previous studies, it has been shown that phosphorus and phosphate can improve the conductivity, change the electronic structure, and accept electrons from catalysts. In this study, we obtained phosphorylated NiAl-layered double hydroxide (P-LDH) nanosheets and used them as a novel cocatalyst in photocatalytic hydrogen evolution. After assembly with g-C₃N₄ via an in situ process, these noble-metal-free composite photocatalysts showed superior photocatalytic hydrogen evolution activity. It was also found that the efficiency of H₂ production on the optimal composite was 1.5 times that of Pt-modified g-C₃N₄. Characterization of the photocatalysts revealed that the effects of P-LDH were different from those of other bimetallic LDHs, showing a lower overpotential and faster reaction kinetics of H₂ evolution. Moreover, it was found that P-LDH has a higher surface work function than that of g-C₃N₄, leading to the formation of an interfacial electric field from CN toward P-LDH. Therefore, modifying P-LDH can efficiently improve the interfacial charge transfer rate, suppress photogenerated charge recombination, and lower the surface overpotential of g-C₃N₄. This study serves as guidance on the design of more effective cocatalysts for photocatalytic hydrogen evolution reactions.     

Study on reaction characteristics of phenolic hydroxyl in coal by using the model compound during direct coal liquefaction

The reaction characteristics of phenolic hydroxyl group were studied under the conditions of direct coal liquefaction. 2-naphthol was used as a coal model compound in this study. Under the conditions of with and without catalysts, a series of experiments were conducted at different temperatures, pressures and reaction time. Gas chromatography-mass spectrometry and gas chromatography were used to identify and quantify the reactants and products respectively. The conversion of 2-naphthol rises with the increase of reaction temperature, initial pressure and catalyst amount. The results indicated that temperature had a significant effect on 2-naphthol conversion, which promoted the dehydroxylation reaction. However, initial pressure had an important influence on the hydrogenation of 2-naphthol and naphthalene. The iron catalyst plays a significant role of cracking instead of hydrogenation. It is concluded that the harsh reaction conditions of high temperature, high pressure, and more catalyst are conducive to promoting dehydroxylation of 2-naphthol. The reaction mechanism was put forward based the experimental results, in which 2-tetralone was an intermediate.     

Developing cross-linked poly(ethylene oxide) membrane by the novel reaction system for H2 purification

In this study, a ‘green” method has been discovered by utilizing the amino functional poly(ethylene oxide) (PEO) and epoxy functional PEO with low molecular weights to synthesis cross-linked membranes for enhancing H₂ purification and CO₂ capture performance by retarding the crystallinity of semi-crystalline polymer of PEO. The cross-linking reaction can happen simply by mixing two materials without using any solvent. The reaction has been characterized by Fourier transform infrared-attenuated total reflectance (FTIR-ATR), X-ray photoelectron spectroscopy (XPS), solid-state ¹³C nuclear magnetic resonance (NMR) and the gel content test. Furthermore, X-ray diffraction (XRD) and differential scanning calorimeter (DSC) confirm the amorphous structure of cross-linked PEO membranes, which should benefit the gas transport. The gas transport properties and the plasticizing phenomenon of CO₂ have been examined in detail. Interestingly, the investigation on CO₂ plasticization phenomenon reveals that the cross-linked PEO membrane should be plasticized immediately after the pressure load. The pressure dependence of CO₂ permeability in the pressure range from 0.25 atm to 30 atm can be separated into two stages based on the permeability increment although the CO₂ permeability continuously increases with the loading pressure. The gas transport results illustrate that CO₂ has much larger permeability than that of any tested gas (including H₂, N₂ and CH₄) attributing to the CO₂-philic characteristic of ethylene oxide (EO) groups in the cross-linked PEO membrane. The good permeability and selectivity make the developed PEO membrane promising for H₂ purification and CO₂ capture applications.     

Damage, failure and stability control of evolutionary process caused by re-exploitation of the residual resources

On the basis of considering the heterogeneity and using the finite element numerical simulation, this thesis investigates the damage of the roof and coal as well as the failure of evolutionary process during the re-exploitation of the residual coal. According to the analysis of the damage field, stress field and the failure process, it explores the damage evolution, stress distribution laws and the damage models. Besides, this thesis puts forward the idea of penetrating and establishing drilling steels aimed at solving the problem of wall carving and roof fall, meanwhile this suggestion accomplishes the successful application effect in the testing ground. This thesis demonstrates that the re-exploitation of the residual coal can be carried out and the safe production can be ensured by adopting some measures. What’s more, the research result provides the theoretical and practical experience for the re-exploitation of the residual coal in the similar conditions.     

A new wave theory of photonic crystals

In this paper, we have presented a wave theory method to study 1D photonic crystals (PCs), and give the new transfer matrix, dispersion relation, and transmissivity. We have calculated the dispersion relation and transmissivity with the new wave theory and the transfer matrix method, and find the dispersion relation and transmissivity are identical for the two kinds of methods. The new wave method can be also used to study 2D and 3D PCs.     

Quantum theory of light diffraction

At present, the theory of light diffraction only has the simple wave-optical approach. In this paper, we study light diffraction with the relativistic quantum theory approach. We find that the slit length, slit width, slit thickness and wavelength of light affect the diffraction intensity and form of diffraction pattern. However, the effect of slit thickness on the diffraction pattern cannot be explained by wave-optical approach, but it can be explained in quantum theory. We compare the theoretical results with single- and multiple-slits experimental data, and find the theoretical results are in accordance with the experimental data. In addition, we give some theory predictions. We think all new predictions will be tested by the light diffraction experiment.     

Application of VIRTEX-4(R) FPGA in Infrared-Camera Control

随着电子技术的不断发展,可编程片上系统(SOPC)逐渐成为系统开发重要的方向.介绍了先进的SOPC平台VIRTEX-4的基本结构和特点,以及基本开发流程,并根据红外相机控制的实际需求,采用1553B总线与上位机实现指令和数据通信.在内嵌的PowerPC硬核中解析指令,FPGA中的控制功能单元根据指令对相机输出控制时序,完成控制功能,并以低电压差分信号(LVDS)方式采集和传输相机图像数据.相对传统的方案基于SOPC的控制模块具有高性能,低功耗,高集成性和灵活性的特点.     

甲烷流量对8.5代非晶硅光伏组件P层材料结构和光学性质的影响

本文研究了甲烷流量对作为工业非晶硅光伏组件的p层材料—非晶碳化硅结构和光学性质的影响.p层非晶碳化硅薄膜采用硅烷和甲烷混合气体在射频等离子体增强化学气相沉积(RF-PECVD)设备中沉积制得,该设备是应用材料公司制造的尺寸为2.2 m × 2.6 m的8.5代系统.采用红外光谱和透射/反射谱分析与沉积工艺相关的键结构和光学性质.相同工艺条件下,当甲烷含量从3000 sccm增加到8850 sccm, p层非晶碳化硅薄膜的光学带隙逐步增加. p层非晶碳化硅薄膜的沉积速率随甲烷流量的增加而逐渐减小,其原因是硅烷-甲烷等离子体中SiH3粒子的减少.文中还通过在不同位置取样和分析沉积速率研究了大面积薄膜的均匀性.     

毛细管电泳法测定甘蔗中 3-硝基丙酸

目的 建立甘蔗中 3-硝基丙酸的毛细管电泳分析方法。 方法 粉碎后的甘蔗经样品提取液提取, 离心 除杂后, 在 228 nm 波长处用毛细管电泳法检测。结果 在优化的实验条件下, 3-硝基丙酸的质量浓度在 1.0~100.0 mg/L 范围内与其对应的校正峰面积呈良好线性关系(r=0.9997)。方法检出限(S/N=3)为 0.3 mg/L, 定量限(S/N=10)为 1.0 mg/L。在 10.0、50.0 mg/L 两个添加水平下, 方法的回收率分别为 95.2%和 103.9%, 相对标准偏差(n=5)分别为 2.2%和 1.3%。结论 本方法简便、灵敏、准确, 可用于甘蔗中 3-硝基丙酸的测定。