Analysis of Threshold Current and Wall-Plug Efficiency of Diode Lasers with Asymmetric Facet Reflectivity

Threshold current and differential quantum efficiency of broad contact lasers with asymmetric facet reflectivity are discussed with the purpose to reveal factors essential for optimisation of the wall-plug efficiency of such lasers. Lasers with low front facet reflectivity and short cavity often exhibit behaviour difficult to explain with a classical theory. More rigorous calculation performed in this work show that differential quantum efficiency is indeed less affected by a change of the front facet reflectivity or cavity length than predicted by such theory. These findings greatly simplify criteria for optimisation of the wall-plug efficiency of broad contact lasers with coated facets.     

等效法在伏安法测量中的应用

本文提出了在伏安法测量中，消除电表内阻对实验结果影响的一种新方法     

复合结构丝中的电流密度分布和巨磁阻抗效应

提出了由中间为高电导率的非铁磁性金属丝外面包裹一层铁磁材料组成的复合结构丝的电流 密度分布和巨磁阻抗(GMI)效应模型，并对Cu/FeCoNi复合丝进行了数值模拟. 结果表明：在 相同的磁性材料几何尺寸和磁特性时，Cu/FeCoNi复合丝铁磁层内的电流随频率的升高比匀 质FeCoNi铁磁丝内的电流更趋于表面分布，而且开始出现趋肤效应时对应的频率明显降低. 当在比较低的频率下就可以观察到明显的MI变化时，复合结构丝中的电阻和电抗变化主要是 由趋肤效应引起，趋肤效应仍然是引起复合结构材料(包括多层薄膜结构) 关键词： 电流密度 巨磁阻抗效应 趋肤效应     

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用TSC程序模拟了EAST装置等离子体放电的全过程。模拟中考虑了自举电流，并加入了离子回旋共振加热ICRH和快波电流驱动FWCD，得到了中心电子温度4.5keV、中心离子温度3.8keV、中心电子密度1.2×1020m–3的D形截面的等离子体。根据模拟结果对EAST装置进行了伏秒数分析，并研究了不同等离子体电流上升时间、有效电荷数Zeff对放电的影响。     

程控电流示波计时电位法

使用计算机产生极化电流具有纯度高，稳定性好和波形形状种类多等优点。研究了极化电流的频率，波形和相角对示波图的影响。对Ｃｄ＾２＋的测定的线性范围为２×１０＾－５～２×１０＾－４ｍｏｌ／Ｌ，相关系数为０．９９７，该方法可且希望用于分析测试和动力学方面的研究。     

VA族元素对阳极铅(Ⅱ)氧化物膜半导体性质的影响(Ⅱ)

用光电化学电流法研究了铅、铅砷、铅锑和铅铋合金在4．5mol·L－1H2SO4溶液（22℃）中，以0．9V（vs．Hg／Hg2SO4）极化7h而形成的阳极膜中的氧化铅的半导体性质，合金添加剂砷、锑和铋对t－PbO（四方氧化铝）和o-PbO（斜方氧化铝）的禁带宽度没有影响，从量子效率和电位的关系可求Pb，Pb－lat％As（at％表示原子百分比，全文同），Pb-lat％Sb和Sb－lat％Bi上膜中t－Pbo的施主密度（ND）分别为9．3×1015，1．0×1016，3．1×1016和1．3×1017cm-3，平带位分别为-0．20，－0．22，－0．28和-0．08V（vs．Hg／Hg2SO4）．比较VA元素砷、锑和铋对上述膜中t－Pbo的ND（从而自由电子密度）和膜中t－Pbo的生长速率的影响，可认为法添加剂砷、锑和铋对阳极膜中t-Pbo的作用符合Hauffe规则．     

Preparation of Micron-size Functional Fluorescent Microspheres

As a kind of special functional microspheres, fluorescent polymer microspheres could be used in cell label and separation, blood flow assay, flow cytometer marking, chemical reaction assay,and in analyst of the transform and diffusion of particles in soil 1. However, one of the most important applications of fluorescent microspheres is in the high-throughput screening of drugs (HTS) 2. Through affinity interaction, radioactive ligands (latent drugs) are bound to fluorescent microspheres covered by receptor, and luminescence is produced by radioactivity, so ligands can be assayed and screened.In this study, we developed a technique for preparing micron-size fluorescent microspheres with different functional groups. The methods included the synthesis of micron-size polystyrene microspheres through the dispersion polymerization of styrene in different media such as ethanol,ethanol-water, and isopropanol; the functional polystyrene microspheres were prepared by introduction of functional monomers into the reaction system of styrene; the functional fluorescent microspheres were obtained by the way of dying functional microspheres in the fluorescent material's ethanol solvent.The average diameter of microspheres was in the range of 1～10 μm, and the distribution was normal distribution. The functional groups included -OH, -CHO, -COOH, -CONH2, and SO3H. The absorbing spectrum and exciting spectrum were tested, the results showed that the maximal absorbance of fluorescent microsphere was near 306.5 nm, and its maximal excitation was near 362 nm. The excitation spectrum of fluorescent material (DPO) and fluorescent microspheres were shown in figure 1, and it indicated that the developed fluorescent microspheres showed the same excitation behavior like DPO, which related to the fluorescent microspheres had stable luminescence property.     

Metabolomic-based investigation of Yinlan alleviating hyperlipidemia by inhibiting blood stasis and phlegm turbidity through the PXR-CYP3A4-ABCB1-FXR pathway

Yinlan lipid regulatory capsule (YL) is a composite traditional Chinese medicine (TCM) new drug to alleviate hyperlipidemia, while its therapeutic mechanism in vivo was not clarified with nontargeted metabolomics investigation. An animal model was established in rats fed a high-fat diet, and their body weights, body mass index (BMI) and blood cholesterol levels were measured. Serum, liver and kidney tissue samples were also extracted for PXR-CYP3A4-ABCB1-FXR signaling pathway research using PCR and UHPLC–MS. The obtained plasma samples were analyzed by UHPLC-Q-TOF-MS metabolomic investigation, which revealed PXR-CYP3A4-related metabolites and changes induced by YL. Finally, the key metabolites were chosen as index components, and their levels in the serum, liver, small intestine and bile were used for simultaneous UHPLC–MS-MS determination. The results indicated that YL was effective in rebalancing blood TG and TC levels (compared to controls). With respect to the PXR-CYP3A4-ABCB1 pathway, as a result of YL’s effect, gene expression or activity of the two targets decreased significantly in both the liver and kidney. The same trend was observed in the serum samples mentioned above. Metabolomics screening and data revealed that 44 metabolites can be regarded as biomarkers related to hyperlipidemia, fatty acids synthesis, and body energy consumption, as well as synthesis, transportation and exertion of cholesterol. YL’s treatment focused on 26 of them, primarily bile acids, indicating that the antihyperlipidemic effect of this drug lies in its inhibitory activity of cholesterol metabolism. Subsequent analysis of those in vivo components revealed that significant increases (compared to the model group) occurred in the blood, liver, small intestine and bile in groups that received medium and high doses of YL (while the low dose was relatively unchanged). Those target components exhibit a close relationship with PXR and/or CYP3A4. The use of YL repressed PXR expression and subsequently decreased CYP3A4 activity. As a result, synthesis of related bile acids increased, while cholesterol levels decreased, consequently leading to the attenuation of hyperlipidemia. This study comprehensively investigated the antihyperlipidemia mechanism of YL based on its repression of PXR-CYP3A4 activity and related metabolite yield, establishing an accurate method for evaluating the therapeutic effect of YL.     

Diffusion current on a nonuniform electrode: Calculation with integral equations

Identity of mathematical problems concerning calculation of the distribution of reactants’ concentrations and the current near the surface of a nonuniform (strip) electrode and distribution of displacements and forces in the case of an elastic layer “antiplane” deformation caused by the punch action. Formulas for calculating the current at a strip electrode are derived for various ratios between the electrode width and the diffusion layer thickness by means of asymptotic methods designed for calculating problems of mechanical contact interactions. It is noted that calculations of the diffusion current for involved activity distributions at the electrode surface may benefit from asymptotic methods of mechanics of contact interactions.     

Superpositioned dielectrophoresis for enhanced trapping efficiency

One of the major applications for dielectrophoresis is selective trapping and fractionation of particles. If the surrounding medium is of low conductivity, the trapping force is high, but if the conductivity increases, the attraction decreases and may even become negative. However, high-conductivity media are essential when working with biological material such as living cells. In this paper, some basic calculations have been performed, and a model has been developed which employs both positive and negative dielectrophoresis in a channel with interdigitated electrodes. The finite element method was utilized to predict the trajectories of Escherichia coli bacteria in the superpositioned electrical fields. It is shown that a drastic improvement of trapping efficiency can be obtained in this way, when a high conductivity medium is employed.