微波弹的物理原理

微波弹是利用高能密度炸药作初级能源，通过磁通压缩发电机或磁流体动力学发电机将炸药爆炸释放出的化学能转变为高功率电脉冲，驱动微波发生器向外辐射高功率微波的一种新概念武器。文章简述了一般微波弹的组成结构、技术原理及其物理基础。     

In situ fibrillation of polyamide 6 in isotactic polypropylene occurring in the laminating‐multiplying die

The polyamide 6 (PA6)/isotactic polypropylene (iPP) in situ fibrillation composites are prepared by a novel extrusion die with an assembly of laminating‐multiplying elements (LMEs). The scanning electron micrographs illustrate that the dividing‐multiplying processes in LMEs elongate, break, and stabilize the dispersed PA6 phase in the iPP matrix along the flowing direction (FD). The morphology development of PA6 with different LME numbers greatly affects the rheological properties, crystalline behaviors, and mechanical properties. The dynamic rheological test performed at 195°C shows that the increased spatial restriction of the high‐aspect‐ratio PA6 particles increases the viscoelastic moduli, complex viscosity, and relaxation time. The crystalline analysis reveals that the heterogeneous nucleation becomes predominant and the transcrystalline morphology is observed in those samples produced by more LMEs. The tensile tests indicate that both, breaking strength and elongation, enhanced simultaneously because of the fibrillation of dispersed phase and the improvement in interfacial adhesion between the fibers and the matrix. Copyright © 2009 John Wiley & Sons, Ltd.     

Chemical surface modifications of microfibrillated cellulose

Microfibrillated cellulose (MFC) was prepared by disintegration of bleached softwood sulphite pulp through mechanical homogenization. The surface of the MFC was modified using different chemical treatments, using reactions both in aqueous- and organic solvents. The modified MFC was characterized with fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Epoxy functionality was introduced onto the MFC surface by oxidation with cerium (IV) followed by grafting of glycidyl methacrylate. The length of the polymer chains could be varied by regulating the amount of glycidyl methacrylate added. Positive charge was introduced to the MFC surface through grafting of hexamethylene diisocyanate, followed by reaction with the amines. Succinic and maleic acid groups could be introduced directly onto the MFC surface as a monolayer by a reaction between the corresponding anhydrides and the surface hydroxyl groups of the MFC.     

基于MFC的化学用语象棋对弈系统开发与应用

在VC++6.0平台上,利用MFC框架开发的一款界面简洁、操作简单、实用性比较高的化学用语象棋游戏,集知识性、趣味性、挑战性、拓展性于一体。系统在双方对弈过程中能自动判断走子正确与否、能否吃子及输入的化学方程式正确与否,设有开始、悔棋、退出3个功能按钮及菜单与计时显示文本框。系统的应用缓解了学生学习化学用语的枯燥乏味,提高了学生对化学用语的学习效率,加强了学生间的合作交流,实现游戏与化学用语教学的有机融合。     

The effect of residual fibres on the micro-topography of cellulose nanopaper

Nanopaper is a new material concept composed of nanocellulose, which has been proposed for a series of applications. Recently, the surface of nanopapers has also been emphasized as an important structure to control. This is due to the potential of nanopaper structures as a substrate for printing functionality, which could expand the applicability of nanopaper as a functionalized biomaterial. In this study, we demonstrate how the roughness of nanopaper is affected by the fraction of residual fibres that were not fibrillated into nanofibrils after a homogenization procedure. The topography and morphology were assessed with laser profilometry, atomic force microscopy and scanning (transmission) electron microscopy. The results show a linear correlation between the estimated fraction of residual fibres and the roughness of the assessed nanopapers. Furthermore, the fraction of residual fibres can be reduced by fractionating the nanocellulose, which is demonstrated in the present work. Such knowledge will be valuable for designing nanopaper surfaces with specific structural characteristics.     

Measurement of Neutron Fluxes and Spectra during the NT-TBM Operation of CN HCSB

Neutronics measurement system provides neutron fluxes and spectra at the locations of beryllium multiplier and tritium breeder during the operation of the NT-TBM （D-D and D-T phase in ITER）. This is important for studying and assessing capabilities of beryllium multiplier and tritium breeder in the China helium cooled solid breeder （CNHCSB）. A special neutron diagnostic system has been proposed that allows to measure neutron fluxes and spectra without interrupt the operation of ITER. This system includes encapsulated foil activation analysis, micro-fission chamber detectors （MFC）, and a compact neutron spectrometer using natural diamond detector （NDD）.     

Properties and characterization of hydrophobized microfibrillated cellulose

Microfibrillated cellulose (MFC) obtained by disintegration of bleached softwood sulphite pulp in a homogenizer, was hydrophobically modified by surface silylation with chlorodimethyl isopropylsilane (CDMIPS). The silylated MFC was characterized by Fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM), transmission electron spectroscopy (TEM), X-ray photoelectron spectroscopy (XPS) and white light interferometry (WLI). The degree of surface substitution (DSS) was determined using Si concentrations from XPS survey scans, as well as deconvoluted peaks in high-resolution C1s XPS spectra. The DSS values obtained by the two methods were found to be in good agreement. MFC with DSS between 0.6 and 1 could be dispersed in a non-flocculating manner into non-polar solvents, TEM observations showing that the material had kept its initial morphological integrity. However, when CDMIPS in excess of 5 mol CDMIPS/glucose unit in the MFC was used, partial solubilization of the MFC occurred, resulting in a drop in the observed DSS and a loss of the microfibrillar character of the material. The wetting properties of films cast from suspension of the silylated MFC were also investigated. The contact angles of water on the films increased with increasing DSS of the MFC, approaching the contact angles observed on super hydrophobic surfaces for the MFC with the highest degree of substitution. This is believed to originate from a combination of low surface energy and surface microstructure in the films.     

聚中性红修饰电极对微生物燃料电池（MFC)脱氮产电性能的影响

利用电聚合方法制备了聚中性红修饰电极,通过扫描电子显微镜（SEM）、能谱仪（EDS）、傅里叶变换红外光谱（FTIR）等表征手段对电极材料的微观结构与组成进行研究。为进一步考察聚中性红修饰电极对微生物燃料电池（MFC）脱氮产电性能的影响,构建了各种不同微生物燃料电池。实验表明,聚中性红修饰阴极微生物燃料电池（CPNR-MFC）具有最强的脱氮和产电性能,其次为聚中性红修饰阳极微生物燃料电池（APNR-MFC)。在不同进水硝氮浓度下,实验组MFCs对硝氮的去除率均达到90%以上,CPNR-MFC具有0.040kg ·m^-3·d^-1的最大硝氮去除速率和15.29 W·m^-3的最大功率密度,较对照组分别提高14.29%和82.51%,而APNR-MFC仅分别提高5.71%和31.93%。通过对比MFCs的电化学特性和微生物特征,探究了聚中性红修饰电极对MFCs性能影响的机理。     

Enzymatic Oxygen Microsensor Based on Bilirubin Oxidase Applied to Microbial Fuel Cells Analysis

A selective oxygen biosensor based on bilirubin oxidase (BOx) was developed. The sensor was used for determining oxygen profiles in a membraneless, single‐chamber microbial fuel cell (SCMFC), fed with raw wastewater. The linear response of the sensor was optimized by a diffusion layer of silica gel. A computer‐controlled stage was used to obtain accurate and precise measurements. Oxygen concentration in biofilms covering electrodes was measured, showing 3 mg L^?1 of O₂ in the bulk solution, decreasing to 0 mg L^?1 in the cathodic biofilm. The MFC generated power in the range of 0–0.08 mW, associated to the oxygen content.     

生物膜电极在以苯酚为燃料的微生物燃料电池中的应用

以苯酚为燃料, 生物膜电极为负极, Ti/SnO₂-Sb₂O₅/PbO₂电极为正极, 构建了双室微生物燃料电池. 利用微电流驯化法和自然驯化法分别制备了生物膜电极, 研究了微生物的挂膜方法、 挂膜时间和负极基底材料种类对微生物燃料电池产电能力的影响. 结果表明, 微电流驯化法优于自然驯化法, 微电流驯化法制备的生物膜电极更利于电池的产电; 微生物的挂膜时间为8 d时, 电池的产电能力最高, 其最大输出功率密度达到39 mW/m²; 不同基底材料生物膜电极所组建的微生物燃料电池产电能力高低顺序为碳毡>石墨>钛网>泡沫钛.