Pentamer arrangements in fragments of human rotavirus inner capsids observed by low dose electron microscopy.

Fragments of disrupted capsids were frequently seen in purified preparations of human rotavirus inner capsids by negative staining method in electron microscopy. The ultrastructures of these fragments were analyzed in comparison with the T = 13L model. Well-resolved pentamers were rarely seen in the fragments on observation at the standard electron doses, but were frequently seen at low electron doses, which meant a better preservation of the steric structure of capsid fragments in the latter case. Thus advantages of low dose electron microscopy have been shown in observation of capsid fragments.     

Enhancing photocatalytic activity of ZnO nanowires by embedding ITO layer as a photogenerated electron collecting layer

The photocatalytic performance of a semiconductor is strongly limited by the inefficient separation of photogenerated carries. In this work, an indium tin oxide (ITO) layer was introduced before the conventional growth of vertically aligned ZnO nanowires by chemical vapor deposition using Al-doped ZnO (AZO) as a seed layer on glass substrates. The ITO layer behaving as an efficient collecting layer of photogenerated electrons strongly suppressed the recombination of photogenerated electrons and holes, which was confirmed by the photoluminescence spectra. The UV-induced photocatalytic activities in aqueous solution were evaluated by selecting rhodamine B as the model contaminant. The ZnO nanowires with ITO layer exhibited notably enhanced photocatalytic activity, which was 9.65 times faster than that of ZnO nanowires alone. It has been proposed that the organic molecules were mainly oxidized by holes concentrated in the valence band of ZnO due to the efficient collection of electrons by ITO layer. Our work highlights that addition of electron collecting layer provides an efficient method to enhance the activity of semiconductor photocatalysts.     

小孢子真菌发癣患儿毛干超微结构改变的扫描电镜观察

为了唤起社会关注及探究发癣的超微病理变化,提醒社会及家庭,尽量使儿童远离宠物或不养宠物,减少任何可能的传染源。本文对6例确诊为小孢子菌癣患儿的毛发,按常规制备扫描电镜样品,扫描电镜下观察分析。结果显示小孢子菌对毛干损害部位主要在毛小皮,而毛干主体的皮质柱则少见损伤。毛小皮细胞的超微变化特征在于使原来呈叠瓦且贴附平整规律的毛小皮,逐步干裂翘起失去固有形象,毛干逐渐由圆滑润泽变成毛刺状,最后导致毛小皮细胞解体或脱落,毛根松动,毛干易折断。上述超微结构改变可能与毛小皮硬角质受体蛋白分子有关。     

The design of masking processes by the method of minimal divergence

The problem of designing a stationary GauSsian noise process of fixed variance so as to optimally mask the possible presence of a given additive stationary Gaussian signal process is considered. A suboptimal solution is obtained by minimizing the divergence distance between the noise and signal-plus-noise processes. Recursive time and frequency domain expressions for the divergence are derived in terms of successive autoregressive approximations of the processes. For short observation times, the minimal divergence masking problem may then be solved by the unconstrained minimization of a convex--and recursively computable-function in the time domain. For long observation times, the problem reduces to that of minimizing the asymptotic divergence rate. This problem may be solved in the frequency domain by straightforward algebraic techniques. A number of examples are given which illustrate the methodology.     

棕化HDI板的激光钻孔流程研究

通过对现有制程能力进行评估改进,通过试验不同设备、不同工艺方法改善激光钻机识别板厚>1.60 mm的棕化HDI板标靶难的问题。     

Aged neuromuscular junctions in the extensor digitorum longus muscle of the rat as revealed by scanning electron microscopy.

We examined the overall morphology of subneural apparatuses (SNAs) at neuromuscular junctions by scanning electron microscopy in the extensor digitorum longus muscle of aged (18 months) rats. Most of aged SNAs were mainly characterized by a large number (more than 20) of cup-like depressions (2-5 microns in diameter) with numerous slit-like junctional folds about 0.1 micron wide and 5 microns at maximum length, while some SNAs consisted of a small number (fewer than 10) of depressions or poorly-developed gutters containing pit-like and/or slit-like junctional folds. Additionally, numerous slits were often found outside the depressions, possibly indicating the pre-existing junctional folds persisted for a long time after the gutter-into-cup transformation of the SNAs. These structural changes of SNAs during ageing are discussed briefly.     

Atomic layer deposition of ZnO electron transporting layers directly onto the active layer of organic solar cells

Interlayers in organic solar cells (OSCs) are used to reduce energy barriers for charge injection/extraction, act as optical spacers, introduce carrier selectivity and increase organic/contact compatibility. To date, the most widely used inorganic interlayers are metal oxides such as TiO₂ and ZnO. However, these materials require harsh deposition conditions that could damage the organic active layers, and hence are generally used in inverted devices. Here we show, for the first time, that judicious selection of materials and processing conditions allow the use of an atomic layer deposition (ALD) system to deposit thin conformal ZnO interlayers on bulk heterojunctions (BHJs). ALD-ZnO interlayers were utilized as electron transporting layers (ETLs) in OSCs and compared to similar devices with solution deposited ZnO nanoparticle (np) ETLs. OSCs with ALD-ZnO ETLs exhibited higher photocurrent densities, J_sc, but lower open circuit voltages, V_oc. The low V_oc is associated with the presence of pinholes and an offset between the ALD-ZnO and PC₇₀BM electron conducting states. This offset results from traps and acceptor sites generated during the low temperature ALD process. To recover the V_oc we introduced a fluorinated phosphonic acid (PA) additive to the blend. We suggest that the additive migrates to the film surface, interacts with the ZnO to produce a denser layer and to passivate traps, effectively improving the device shunt resistance and energy level alignment and increasing V_oc. Overall, the devices with PA and ALD-ZnO ETLs possess significantly higher power conversion efficiencies (PCEs) than those with np-ZnO ETLs. For example, the champion ALD-ZnO device PCE is 3.5%, while that with np-ZnO is 2.75%.     

高血压大鼠第四脑室外侧隐窝室管膜细胞超微结构变化的电镜观察

目的:观察一氧化氮(NO)缺乏型高血压大鼠,第四脑室外侧隐窝室管膜细胞及其分泌状态的超微结构变化.方法:30只健康雄性Wistar大鼠,其中20只予以一氧化氮合酶抑制剂左旋硝基精氨酸(L-NNA) 15 mg/d,腹腔注射,复制高血压动物模型;10只予以0.9%氯化钠2 mL/d腹腔注射作为对照.对照组、用药2周组和用...     

The influence of growth temperature and precursors’ doses on electrical parameters of ZnO thin films grown by atomic layer deposition technique

In this paper we report on the low-temperature growth (T_s=30-250 °C) of zinc oxide thin films by atomic layer deposition method using two different organic zinc precursors: diethylzinc and (for comparison) dimethylzinc, and deionized water as an oxygen precursor. An evident influence of growth temperature and precursors’ doses on electron concentration and Hall mobility of obtained zinc oxide layers is presented. The lowest achieved room-temperature electron concentration was at the level of 10¹⁶ cm⁻³ with mobility up to 110 cm²/V s.     

改良电镜固定方法对腹膜表面活性层的保护

有研究提示在腹膜表面有一层液体滞留层,它们粘附于腹膜表面,对腹膜的运转功能有十分重要的作用,尽管对腹膜表面液体层有种种猜测,在形态学方面这一活性层的存在却迟迟未能被证实。本文介绍使用了改良的固定方法,在透射电镜下第一次观察到了该活性层的存在。     

以Ta2O5为电子加速层的MEH-PPV的发光

以Ta2O5为加速层,制备了结构为ITO/Ta2O5/MEH-PPV/Ta2O5/Al的电致发光(EL)器件.通过对器件的EL特性、发光波形随驱动电压变化关系等的研究发现,器件的发光性质和发光机理与固态类阴极射线发光现象一致.研究结果表明,固态类阴极射线发光是一种普遍现象,用具有加速电子能力的Ta2O5作为加速层的EL...     

扫描电镜揭示家兔心包的结构特点及其心房肽转运意义

采用常规和NaOH消蚀／叔丁醇冻结干燥法，应用扫描电镜观察家兔心包腔面的结构特征，为心包液中心房肽的来源、去向及其意义，提供形态学依据。结果显示：脏层心包表面可见完整的大型膜包分泌颗粒（1μm～4μm）；壁层心包表面，可见立方形和扁平形两种上皮细胞；在相邻的3个立方细胞之间，存在三角形的孔隙（5μm）；还可见到乳斑样结构。在NaOH消蚀处理的心包，可见成簇筛孔（10μm～20μm）组成的筛斑，另有网状纤维把筛孔分割成许多网眼（0．5μm～2μm）。这些结构特征提示，心房颗粒或心房肽可能通过心外膜直接进入心包腔，再由心包膜的淋巴管吸收、转运而发挥作用。     

多层板内层图形蚀刻工艺及品质控制技术探讨

该文对多层印制板内层图形制作之蚀刻工艺技术进行了简单介绍,对该制程的品质控制进行了较为详细的论述。     

The sensitivity to technological innovations of the doses delivered by optimized mammography systems

Multiparameter optimizations have been carried out to study the effects of hypothetical technological advances on the patient doses required to maintain a given image quality in mammography. The assumed advances include: improvement in the power loading limits of the tube focal spot, increased absorption efficiency for a given detector resolution, increases in detector system gain, and changes in the exposure time limitations that result from patient motion. The optimization permits system geometry, kVp of the examination, filtration, detector resolution, focal spot size, and grid characteristics to vary simultaneously and self-consistently subject to image quality as well as technological constraints. The effects of technological innovations were measured by systematically varying the technological constraints to reflect hypothetical improvements and comparing the resulting minimized doses, required to maintain constant image quality, to a baseline optimized system derived from a set of baseline technological capabilities.