饮用水中挥发性三卤甲烷(THM)_s测定方法的改进

本文使用吹扫捕集法来前处理水样,用带有电子捕获检测(ECD)的气相色谱仪来测定水中三卤甲烷(THM)_s。水样加标回收率在85%～115%之间,相对标准偏差在5%左右。实验结果表明,该法具有简单、快速、灵敏的特点。     

A localized surface plasmon resonance based immunosensor for the detection of casein in milk

In this research, a localized surface plasmon resonance (LSPR) immunosensor based on gold-capped nanoparticle substrate for detecting casein, one of the most potent allergens in milk, was developed. The fabrication of the gold-capped nanoparticle substrate involved a surface-modified silica nanoparticle layer (core) on the slide glass substrate between bottom and top gold layers (shell). The absorbance peak of the gold-capped nanoparticle substrate was observed at ∼520 nm. In addition, the atomic force microscopy (AFM) images demonstrated that the nanoparticles formed a monolayer on the slide glass. After immobilizing anti-casein antibody on the surface, our device, casein immunosensor, could be applied easily for the detection of casein in the raw milk sample without a difficult pretreatment. Under the optimum conditions, the detection limit of the casein immunosensor was determined as 10 ng/mL. Our device brings several advantages to the existing LSPR-based biosensors with its easy fabrication, simple handling, low-cost, and high sensitivity.     

AgWC12C3的粉末粒度对产品密度的影响

粉末粒度对粉末制品的性能具有重要的影响,而这些影响主要通过改善材料的密度来达到。该文根据模拟粉末堆积模型,确定相对合理的粒度组成,并通过试验予以验证。     

Investigation of the Correlation between Texture and Microstructure on a Submicrometer Scale in the TEM

In recent years the investigation of local texture and microstructure by analysis of electron backscatter diffraction patterns (EBSP) in the SEM has become a very powerful and popular method. With the introduction of SEM with field emission guns (FEG) the spatial resolution of EBSP measurements could be enhanced from 500 nm with a tungsten emitter to better than 50 nm. This evolution of SEM techniques raises the question whether transmission electron microscopy (TEM) still has fields of application in texture research. The present article answers this question with a clear “yes” and presents three examples of investigations where TEM is indispensable. The three examples comprise the investigation of the correlation between dislocation structure and deformation texture, a study on nucleation mechanisms of recrystallization in highly deformed metals and the investigation of microtexture and microstructure in nanocrystalline materials. Together with the presentation of these cases some of the necessary measurement techniques are described briefly. It is shown that TEM has to be applied when highest spatial resolution of orientation determination and imaging and high accuracy of orientation determination are to be reached, when the three‐dimensional and quantitative characterization of lattice defects is required or when materials with a high density of lattice defects are to be investigated.     

新型高温永磁体的研制

通过分析影响磁体高温性能的因素,设计了新磁体的成分为:Cu含量高,Fe含量低,Zr适量,Sm含量高;采用粉末冶金工艺制备了高温Sm_2(CoFeCuZr)_(17)永磁体。制得的磁体室温磁性能为:B_r1.075 T,H_(ei)2 098.2 kA/m,H_(eb) 776.1 kA/m,H_k843.8 kA/m,(BH)_(max)210.0 kj/m~3;在200℃时的磁性能为:B_r0.991 T,H_(ci)1 175.7 kA/m,H_(cb)531.7 kA/m,H_k577.9 kA/m,(BH)_(max)172.5 kJ/m~3;矫顽力温度系数β(20～200℃)为-0.24％/℃。经理论分析和实验验证,磁体的使用温度均超过400℃,为高温环境(高于400℃)提供了一种实用性永磁材料。     

Improvement of photon collection in Cu(In,Ga)Se2 solar cells and modules by fluorescent frequency conversion

Fluorescent photon down conversion for the improvement of the blue response of ZnO/CdS/Cu(In,Ga)Se₂ heterojunction solar cells and modules is investigated. Fluorescent dyes of the series Lumogen® F are analyzed by optical transmission and reflection as well as by photoluminescence measurements. A spectral transfer matrix formalism is introduced that allows to predict the suitability of a luminescent dye as a down-converter for a given solar cell from its absorption/emission properties. We find that Lumogen® F Violet 570 and Lumogen® F Yellow 083 as well as a combination of both yields improvements for Cu(In,Ga)Se₂ solar modules. Particularly, we find that the short circuit current density of a Cu(In,Ga)Se₂ mini-module is improved by 1.5 mA cm^− 2 when applying a varnish with a combination of Lumogen® F Violet and Yellow. About 0.5 mA cm^− 2 of this improvement is due to a reduced overall reflectance and an improvement of 1 mA cm^− 2 results from the frequency conversion by the dyes.     

Reversible changes of the fill factor in the ZnO/CdS/Cu(In,Ga)Se2 solar cells

The reversible persistent changes of the fill factor (FF) induced by the illumination and voltage bias along with changes in the electronic properties of the ZnO/CdS/Cu(In,Ga)Se₂ photovoltaic devices have been studied. Admittance spectroscopy and capacitance–voltage characterization reveal a correlation between the FF and the space charge distribution within the absorber. Our experiments provide evidence that a major source of FF loss in efficient devices is caused by excess negative charge close to the interface. We explain the persistent changes in the net acceptor concentration in the interface region by the relaxation effects due to compensating donors—the same mechanism, which leads to metastable changes of the doping level in the bulk of the absorber.     

添加微量铝对TS-2合成及苯酚羟基化的影响

以硅溶胶为硅源合成分子筛TS 2时 ,在溶胶制备过程中添加微量的铝 ,可以降低模板剂氢氧化四丁基铵 (TBAOH)的用量 ,当TBAOH/SiO2 降低到 0 .1以下时 ,仍然合成了性能优良的TS 2 ,而且用于苯酚过氧化氢羟基化反应过程中催化活性也大大提高。所得催化剂用XRD ,IR ,ICP进行了表征     

浅谈工程项目的预算(成本)管理

从施工单位管理的角度出发,在工程投标、施工前、施工中及完工等不同阶段对项目的预算管理重要性进行描述,充分表明了只有加强各个阶段的预算(成本)管理,才能真正提高经济效益。