透过检测中的准直镜精度容限

在干涉检验过程中, 被检元件的面形误差检测精度受到干涉仪系统结构的影响, 从而降低测量结果的可靠性。为了得到较高的检测精度, 必须对检测系统进行分析, 建立测量误差和系统结构的关联度。根据菲涅耳衍射近似理论, 就菲佐干涉仪中的准直镜和标准镜面形误差对透过检测的影响进行了研究。通过对波前相位传递情况的分析, 得出波前误差和系统结构参量的相关性, 去除空腔系统误差, 优化结构参量, 并建立准直镜误差容限表达式。经计算得出, 当被检面形变误差为0.2λ时, 测试误差可以达到0.02λ, 而对准直镜的面形误差要求

Field studies on the environmental factors in controlling microcystin production in the subtropical shallow lakes of the Yangtze River

Microcystin (MC) problem made more and more care about in China, intercellular MC (Int-MC) and cellular MC (Cel-MC) were important contents to reflect the producing-MC ability by cyanobacteria and by lakes. To study the correlations between Int-MC, Cel-MC concentration and biological and environmental factors, eight cyanobacterial blooming lakes were studied in the middle and lower reaches of the Yangtze River. Microcystin-RR (MC-RR) and Microcystin-LR (MC-LR) were the primary toxin variants in our data. From the linear correlations between MC and environmental factors, cellular-YR had significant correlation with most of chemical factors except total nitrogen (TN) and the ratio of total nitrogen and total phosphorus (TN/TP), most intracellular MC analogues had significant correlations with total dissolved nitrogen (TDN), ammonium (NH4+), nitrite (NO2-), TP, total dissolved phosphorus (TDP), Microcystis. From the canonal correspondence analysis, Int-MC concentrations were closely related with the chemical and biological factors, such as TP, total organic carbon (TOC), chlorophyll a (Chl a), Microcystis biomass, et al. While Cel-MC contents, especially Cel-RR and Cel-LR, were closely related with light environmental in the lakes such as water depth and transparence.

Low -temperature preparation of ZnO films on Si substrates by MOCVD

ZnO films were deposited on Si（100） substrates at 300℃ by metal - organic chemical vapor deposition（MOCVD）. The effect of different ratios of DEZn to N2O on crystal quality was analyzed. It is found that the optimum ratio of DEZn to N2O is 2.1. And in this optimum growth condition, X - ray diffraction （XRD） and scanning probe morphology （SPM） images indicate that the films grow along the c - axis orientation. ZnO film exhibits a strong UV optical absorption near 388 nm. And the optical absorbance is close to zero,that indicates nearly 100% optical transparence. Photoluminescence （PL） spectrum shows only strong near - band - edge emissions with little or no deep - level emission related to defects. The full - width at half - maximum （FWHM） of the ultraviolet emission peak is 80meV. The results indicate that better crystal quality can be obtained.

All-organic tunnel junctions as connecting units in tandem organic solar cell

We employed organic heterojunction films as all-organic connecting units to fabricate tandem organic photovoltaic cells by continuous deposition. The all-organic connecting units with a better transparence and a lower sublimation temperature became an effective recombination center for electrons and holes photogenerated in front cell and back cell, respectively. Tunnel mechanism was proposed to explain the combination of photogenerated carrier.

互联网上机器人的遥控理论与方法综述

给出了系统的研究模型,指出系统控制和设计必须考虑的3个关键问题:稳定性、透明性和时延处理.阐述了4个主要的稳定性分析方法:Lyapunov稳定性、输入输出稳定性、无源稳定性和基于事件的稳定性,总结了这些方法的优势和局限性.接着,给出了几种主要的控制策略,指出了现有控制方法的优缺点.最后,提出了进一步的主要研究方向.