Design and optimization of a monolithic GaInP/GaInAs tandem solar cell

We have theoretically calculated the photovoltaic conversion efficiency of a monolithic dual-junction GaInP/GaInAs device,which can be experimentally fabricated on a binary GaAs substrate.By optimizing the bandgap combination of the considered structure,an improvement of conversion efficiency has been observed in comparison to the conventional GaInP_2/GaAs system.For the suggested bandgap combination 1.83 eV/1.335 eV,our calculation indicates that the attainable efficiency can be enhanced up to 40.45%(30...     

Epitaxial growth of ZnO on GaN/sapphire substrate by radio-frequency magnetron sputtering

Zinc oxide (ZnO) thin films were grown on n-GaN/sapphire substrates by radio-frequency (RF) magnetron sputtering. The films were grown at substrate temperatures ranging from 400 to 700 ℃ for 1 h at a RF power of 80 W in pure Ar gas ambient. The effect of the substrate temperature on the structural and optical properties of these films was investigated by X-ray diffraction (XRD), atomic force microscopy (AFM) and photoluminescence (PL) spectra. XRD results indicated that ZnO films exhibited wurtzite symmetry and c-axis orientation when grown epitaxially on n-GaN/sapphire. The best crystalline quality of the ZnO film is obtained at a growth temperature of 600 ℃. AFM results indicate that the growth mode and degree of epitaxy strongly depend on the substrate temperature. In PL measurement, the intensity of ultraviolet emission increased initially with the rise of the substrate temperature, and then decreased with the temperature. The highest UV intensity is obtained for the film grown at 600 ℃ with best crystallization.     

草莓型P(St-BA)/SiO_2纳米复合微球制备与表征

在混合溶剂丙酮/水介质中,以纳米SiO_2粒子为Pickering乳化剂,阳离子单体甲基丙烯酰氧乙基三甲基氯化铵(MTC)为辅助单体,苯乙烯(St)和丙烯酸丁酯(BA)发生无皂乳液聚合制备了固含量高达25%的草莓型P(St-BA)/SiO_2纳米复合微球。研究了初始硅溶胶用量、软硬单体配比对复合微球形态、粒径和SiO_2吸附量的影响,并测试了乳胶膜的吸水性能。结果表明:在实验范围内制备得到的复合微球粒径在290～560 nm之间,SiO_2的吸附量介于28～34wt%之间。     

母乳中长链甘油三酯研究进展

母乳中甘油三酯的结构对于婴幼儿的脂肪消化吸收具有重要影响。作者所在团队前期研究结果显示,母乳脂肪天然富含中长链甘油三酯（MLCT）,是母乳中含量最丰富的一类甘油三酯,其质量约占总甘油三酯的30%,主要结构是一个中链脂肪酸和两个长链脂肪酸构成的单中链型甘油三酯（MLL）。母乳中几乎不含中链甘油三酯（MCT）。作者综述了母乳脂肪中MLCT的含量、组成、影响因素以及母乳与婴幼儿配方奶粉中甘油三酯的差异,总结了MLCT的消化特性,以及MLCT型母乳替代脂的研究进展,为新型配方奶粉脂肪的开发提供理论依据。     

开关柜局部放电检测定位技术的应用研究

介绍了对开关柜局部放电暂态对地电压法和超高频法检测定位技术,对超高频电磁波在开关柜中的传播特性进行了理论分析。在实际运行10 kV开关柜中研究了暂态对地电压法和超高频法局部放电定位技术的有效性和可行性。结果表明:采用暂态对地电压法,超高频检测幅值比较和时间差法的局部放电定位技术对开关柜局部放电缺陷的检测和定位是有效可行的。高压开关柜局部放电暂态对地电压法和超高频法检测定位技术可为现场应用提供实验基础。     

基于网络分析仪的GIS局部放电在线监测特高频传感器现场校核技术

如何校核已投运的传感器性能是保障气体绝缘金属封闭开关设备（gas-insulated metal-enclosed switchgear, GIS）局部放电监测可靠性的重要课题。基于网络分析仪,采用扫频方法测试安装在实体 GIS 上的传感器的响应特性,并研究其与特高频传感器平均有效高度的关系。通过比较分析发现,实体 GIS 上传感器的等效频率响应特性与其吉赫兹横电磁波（gigahertz transverse electromagnetic,GTEM）小室内的等效高度曲线具有相似的频谱特征,实体 GIS上传感器的平均等效响应幅值与 GTEM小室内的平均有效高度具有相同的变化规律;结论认为,通过利用网络分析仪进行频响特性测试,可以有效反映特定型号 GIS 结构下的特高频传感器性能。基于该结果,提出了基于网络分析仪的 GIS局部放电监测特高频传感器现场校核方法。     

调节阀与流量计构成的闭环系统

本文介绍了位置调节阀与流量计组成的流量控制闭环系统。详细描述系统构成和其功能、并介绍了阀的调整和使用以及PID参数调整的方法。     

利用SAS软件优化丙酮丁醇梭状芽孢杆菌产丁醇的发酵条件

通过单因素优化实验、Plackett-Burman实验和Box-Benhnken响应面实验对影响丙酮丁醇梭状芽孢杆菌产丁醇能力的主要因素进行优化,得到了回归方程:Y_2=8.583 367-0.002 125×X_7-0.416 5×X_8+0.297 567×X_9+0.070 692×X_(10)-0.550 233×X_7~2-0.037 9×X_7×X_8-0.001 775×X_7×X_9-0.053 75×X_7×X_(10) +0.037 529×X_8~2-0.182 675×X_8×X_9+0.032 475×X_8×X_(10)+0.126 754×X_9~2-0.069×X_9×X_(10)- 0.588 208×X_(10)~2。对回归方程进行岭嵴分析,得到了丙酮丁醇梭状芽孢杆菌的优化培养条件,即装液量为310 mL,种龄为18h,静态培养,接种量为6%,温度为37℃,初始pH值5.5,在此基础上进行7L发酵罐扩大培养,优化前和优化后的分批发酵结果相比,优化后7L罐最佳浓度的产量为10.55g/L,比原产量8.02g/L提高了31.25%,比有关文献报道的产量高出11.64%。     

基于未确知聚类法的底板采动破坏深度动态预测

根据微震监测结果,利用未确知聚类优化法,选取采深、煤层倾角、采厚、构造影响程度4个主要影响因素作为判别指标,建立煤矿底板采动破坏深度动态预测模型。利用微震实测的18组数据作为训练样本,以样本均值为聚类中心,采用信息熵理论确定各判别指标的权重,通过计算样本的多指标综合测度与所属类别样本均值乘积之和获得底板采动破坏深度的预测值,并对样本数据进行逐一检验。为进一步验证该方法的可靠性,另选5组样本进行预测,将预测值与微震实测结果做了比较。研究结果表明:底板采动破坏深度的预测值与实测值的平均相对误差不超过1%,底板采动破坏深度动态预测模型是可靠实用的,可以在同类矿山进行推广应用。     

High-throughput sample preparation for gene expression profiling and in vitro target validation

The demand for high-throughput RNA isolation has been dramatically increasing with wide applications of RNAi, expression profiling, and molecular diagnosis. A comparison of various RNA isolation methods that have been adapted to high-throughput platforms, focusing on consistently high yield and quality of isolated RNA, reduction of cross-contamination, and simplicity and robustness of the protocol is presented. The streamlining of RNA isolation with RNA quantification by qRT-PCR and amplification for microarray analysis is also discussed. In general, a microspheric bead-based approach results in more consistent RNA recovery than glass fiber filter-based RNA isolation method, and RNA can be eluted in a smaller volume. This is because beads can be fully re-suspended in solution to enable more thorough mixing, washing, and elution, whereas the glass fiber matrix is fixed in a filter plate.