NIR光谱法快速分析总黄酮醇苷和萜类内酯

采用NIR法和化学计量学方法构建了银杏叶片中的总黄酮醇苷和萜类内酯含量的定量分析模型。通过PLS建立数学模型,并对预测集样品进行预测。39份样品经交叉验证建立校正模型,RSMECV分别为0.104和0.063。R分别为0.978 8和0.961 9。用13份样品进行预测,R达0.919 9和0.931 8,RSMEP分别为0.107和0.105。该方法简便快速,结果准确,可应用于不同批次银杏叶片样品的进行快速检查或质量控制。     

A review of catchment management in the new context of drinking water safety plans

By managing a catchment effectively, the range and amount of contaminants entering waters used for public water supply can be reduced, with resultant benefits for both water companies and consumers. Consequently, catchment management is increasingly being recognised as being at the heart of the water environment. An overview of current and previous catchment management initiatives is given, along with the European Landscape Convention, which could be used as a vehicle for the implementation of a national catchment management strategy. The adoption of the drinking water safety plan approach is strongly advocated by the World Health Organisation, and effective catchment management underpins this approach. Effective management of our catchments will also make a significant contribution to meeting our obligations under the Water Framework Directive, by helping to address the serious issue of diffuse pollution from agriculture.     

不排水加载条件下K_0固结饱和砂土失稳预测

基于二阶功准则及变形分叉理论,建立了分散性失稳和应变局部化失稳的理论判别准则,对K0固结不排水加载条件下饱和砂土的失稳特性进行了理论研究。分析结果表明,三轴应力状态下,土体表现为分散性失稳模式,应变局部化则不会发生。在试样初始状态较密实的状态下,由于相变作用,土体能够保持稳定,直至达到塑性极限破坏。在平面应变状态下,分散性失稳和应变局部化均可能发生,且分散性失稳先于应变局部化失稳出现。非共轴塑性流动法则的引入对分散性失稳预测结果无影响,然而对应变局部化的预测结果影响较大,且只有在引入了非共轴流动法则的条件下,应变局部化的理论预测结果才能与试验结果一致。     

SLAB View软件在含硫天然气井井喷泄漏扩散模拟中的应用

介绍了SLAB重气泄漏扩散模型,并运用SLAB View软件模拟了某含硫气井发生井喷事故H2S云团的扩散过程和危害区域,得出了H2S云团在指定浓度平均时间下的影响范围,以及指定浓度H2S云团出现在最远距离的时间和最远下风向扩散距离。结果表明,SLAB View软件能方便、快速地模拟平坦地形下含硫天然气井喷泄漏扩散过程,预测事故泄漏扩散后果和影响范围。     

Polyaniline sensitized Pt@TiO2 for visible-light-driven H2 generation

Polyaniline is a typical conducting polymer with high migration electron rate, good stability, eco-friendly properties, and high absorption coefficients for visible light. In the present study, polyaniline decorated Pt@TiO₂ for visible light-driven H₂ generation is reported for the first time. The above-mentioned nanocomposite is prepared through a simple oxidative-polymerization and characterized by infrared spectroscopy, transmission electron microscopy, X–ray diffraction, thermogravimetric analysis, and ultraviolet–visible diffuse reflectance spectra. Polyaniline modification improves the absorption of the nanocomposite in visible light region via a photosensitization effect similar to dye–sensitization but does not influence the crystal structure and size of Pt@TiO₂. The polyaniline modified Pt@TiO₂ exhibits a remarkable visible light activity (61.8 μmol h⁻¹ g⁻¹) and good stability for H₂ generation (with an average apparent quantum yield of 10.1%) with thioglycolic acid as an electron donor. This work provides new insights into using conducting polymers, including polyaniline, as a sensitizer to modify Pt@TiO₂ for visible-light hydrogen generation.     

Gold—sulphide versus sulphide centres on (100) AgIBr surfaces: characterization and mechanism

Abstract

Cubic AgIBr emulsions sensitized by sulphur-plus-gold with gold added at 40°C either before or after sulphur sensitization at 70°C were prepared and studied. Gold ions incorporate into the silver-sulphide centres and decrease the diffuse reflectance spectroscopy (DRS) response. The emulsions with gold added before the heat cycle through 70°C showed a dependence on the amount of gold for a speed increase at 0.01 s and their reciprocity failure property, whereas the emulsion with gold added at 40°C after the heat cycle did not. Gold present at the elevated sensitization temperature enhanced long-wavelength sensitivity in a wider wavelength region than gold added after the heat cycle. The different sensitometric behaviour between gold added before or after the heat cycle could be explained by the enhanced thiosulphate conversion effect of gold at 70°C. The electron trapping energy level of the sensitization centre is speculated to be slightly higher for sulphur-plus-gold than sulphur sensitization. Opposite trends were observed in DRS and long-wavelength sensitivity when the gold level increased. Whether the electronic effect of gold during exposure on top of its latensification effect in sulphur-plus-gold sensitization could be observed seems to be dependent on the sulphur level. A mechanism is proposed.     

Structural modifications in stretch-induced crystallization in PVDF films as measured by small-angle X-ray scattering

The nanostructure of stretched and nonstretched PVDF samples was studied by small-angle X-ray scattering (SAXS). The crystallinity of the samples was determined by wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC), and crystalline phases by Fourier transform infrared spectroscopy (FTIR). The nanostructure can be described by a lamellar stacking of crystalline and amorphous layers, with a fairly well defined long period D and a diffuse-boundary in the interface between the crystalline and amorphous phases. The crystallinity of the stretched sample was found to be greater than that of the nonstretched sample. The long period D and the thicknesses of the crystalline lamellae T_c were found to be greater in the stretched sample than those in the nonstretched sample. The thickness of the diffuse-boundary was evaluated as being ∼ 1.4 nm in the nonstretched sample and 1.1 nm in the stretched sample. It was concluded that the growth of the thickness of the crystalline layer induced by the stretching process (stretch-induced crystallization) occurs partially at expense of the diffuse boundary and also by the coarsening of the structure with the stretching process, because of the diminution in the surface area to volume ratio observed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Characteristics and application of diffuse discharge of water electrode in air

Plasma water treatment technology, which aims to produce strong oxidizing reactive particles that act on the gas–liquid interface by way of discharging, is used to treat the organic pollutants that do not degrade easily in water. This paper presents a diffuse-discharge plasma water treatment method, which is realized by constructing a conical air gap through an uneven medium layer. The proposed method uses water as one electrode, and a dielectric barrier discharge electrode is constructed by using an uneven dielectric. The electric field distribution in the discharge space will be uneven, wherein the long gap electric field will have a smaller intensity, while the short one will have a larger intensity. A diffuse glow discharge is formed in the cavity. With this type of plasma water treatment equipment, a methyl orange solution with a concentration of 10 mg l^-1 was treated, and the removal rate was found to reach 88.96%.     

Photocatalytic Self-Cleaning of Wool Fibers Coated with Synthesized Nano-Sized Titanium Dioxide

Nano-sized TiO₂ was successfully synthesized and deposited onto wool fibers using the sol–gel process at ambient temperature. The prepared samples were characterized using several structural, textural, and morphological techniques. The electron micrographs show formation of TiO₂ nanoparticles 10–30 nm in size. The photocatalytic activity of TiO₂-coated wool fibers was investigated through the solid-phase self-cleaning of methylene blue (MB) under UV-vis irradiation by the diffuse reflectance spectroscopy (DRS) method. The fibers' structure is not altered upon light exposure. This preparation technique can also be applied to new fabrics to create self-cleaning and UV irradiation protection properties in them.     

Theoretical and experimental study on the application of diffuse‐reflection concentrators in PV/T solar system

In order to improve the practicability of PV/T solar system, we proposed the theory and method on the application of diffuse‐reflection concentrator in the PV/T solar system and analyzed the concentration characteristics of this proposed application. In addition, we designed experimental prototype of PV/T solar system and conducted test and analysis of the thermal and electrical characteristics of the PV/T solar system with or without a concentrator, respectively. The results showed that for the PV/T solar system with diffuse‐reflection concentrator, the amount of incident irradiance was increased by an average of 26% during test period, and the 200‐L water in the system was heated to 58 °C, which was 12 °C higher than that of PV/T solar system without diffuse‐reflection concentrator; moreover, the max output power was increased by 11%. Therefore, it is a feasible way to improve the practicability of PT/V solar system by integrating a diffuse‐reflection concentrator. Copyright © 2016 John Wiley & Sons, Ltd.