树qu红核的细胞构筑和红核脊髓束的起源

用Nissl法染色和HRP注入树qu脊髓的不同节段,结果表明,树qu红核和上丘高度向吻侧延伸至乳头体内侧核尾端,细胞柱呈梭状,长约3.7mm,最大处直径2mm。它由大(60-100#mu#m)、中(30-50#mu#m)和小型(10-25#mu#m)细胞构成。红核吻段大细胞较多,占60.7%,中尾段中小型细胞多,占71.7%,, 中、小细胞散在分布于大细胞之间。树qu的红核-脊髓束主要由对侧红核大、中和小型细胞发出的纤维组成;红核吻段背侧部,中尾段的腹部、腹中部和腹中背部细胞发出的纤维交叉投射到颈吻段;红核吻、中、尾段的腹部、腹中部和腹中背部细胞发出的纤维还投射到对侧颈尾段;红核中尾段的腹部、腹中部、腹中背部细胞也有纤维交叉投射到腰段;只有红核吻段和尾段少量细胞发出的纤维投射到同侧颈段。

思茅地区咖啡天牛天敌的多样性调查和控制评价

在1994-1997年的调查研究中发现思茅地区拥有丰富的天敌资源。共鉴定出8种主要捕食和寄生于咖啡天牛的天敌,其中蚂蚁类4种、寄生蜂2种。饲养和调查结果显示,黑褐举腹蚁、立毛举腹蚁、间斑举腹姬蜂和蠼螋4种捕食或寄生性天敌,自然种群大、控制能力强,有很大的利用前景。

The decline and impending extinction of the South China tiger

The South China tiger Panthera tigris amoyensis is the rarest of the five living tiger subspecies, the most critically threatened and the closest to extinction. No wild South China tigers have been seen by officials for 25 years and one was last brought into captivity 27 years ago. The 19 reserves listed by the Chinese Ministry of Forestry within the presumed range of the tiger are spatially fragmented and most are too small to support viable tiger populations. Over the last 40 years wild populations have declined from thousands to a scattered few. Despite its plight and occasional anecdotal reports of sightings by local people, no intensive field study has been conducted on this tiger subspecies and its habitat. The captive population of about 50 tigers, derived from six wild-caught founders, is genetically impoverished with low reproductive output. Given the size and fragmentation of potential tiger habitat, saving what remains of the captive population may be the only option left to prevent extinction of this tiger subspecies, and even this option is becoming increasingly less probable. This precarious dilemma demands that conservation priorities be re-evaluated and action taken immediately to decide if recovery of the wild population will be possible.

Stress-induced domain dynamics and phase transitions in epitaxially grown VO₂ nanowires.

We demonstrate that surface stresses in epitaxially grown VO₂ nanowires (NWs) have a strong effect on the appearance and stability of intermediate insulating M₂ phases, as well as the spatial distribution of insulating and metallic domains during structural phase transitions. During the transition from an insulating M1 phase to a metallic R phase, the coexistence of insulating M₁ and M₂ phases with the absence of a metallic R phase was observed at atmospheric pressure. In addition, we show that, for a VO₂ NW without the presence of an epitaxial interface, surface stresses dominantly lead to spatially inhomogeneous phase transitions between insulating and metallic phases. In contrast, for a VO₂ NW with the presence of an epitaxial interface, the strong epitaxial interface interaction leads to additional stresses resulting in uniformly alternating insulating and metallic domains along the NW length.

Adaptive enhancement of multimode fibre bandwidth by twin-spot offset launch

A binary grating on a Spatial Light Modulator generates twin antiphase spots with adjustable positions across the core of a multimode fibre allowing adaptive excitation of antisymmetric mode-groups for improving modal dispersion or modal multiplexing. © 2011 IEEE.

Multiple color reflection in a single unit cell using double-layer electrochromic reaction

Multiple color states have been realized in single unit cell using double electrochromic (EC) reaction. The precise control of bistability in EC compounds which can maintain several colors on the two separated electrodes allows this new type of pixel to be realized. The specific electrical driving gives a way to maintain both sides in the reduced EC states and this colors overlapping in the vertical view direction can achieve the black state. The four color states (G, B, W, BK) in one cell/pixel can make a valuable progress to achieve a high quality color devices such like electronic paper, outdoor billboard, smart window and flexible display using external light source. © 2012 Optical Society of America.

斜生栅藻中虾青素的积累过程及其光合活性变化

分析了斜生栅藻(Scenedesmus obliquus)在光温(30℃,180μmol/m2·s)胁迫条件下积累虾青素的过程,观察了该过程中细胞形态及细胞光合生理的变化。胁迫条件下,细胞在48h内生成并积累了包括海胆酮、角黄素、金盏花黄素和金盏花红素在内的多种次生类胡萝卜素,并合成了虾青素及其酯。该过程中,细胞形态由两端尖细变得不规则、膨大,原来由4、8个细胞组成的定形群体变为游离的单个细胞或2个细胞组成的群体。藻细胞光合速率在24h内先下降后上升,而后又呈现下降趋势,从34.29μmolO2/mg C

Blade Loading and Its Application in the Mean-Line Design of Low Pressure Turbines

In order to minimize the number of iterations to a turbine design, reasonable choices of the key parameters must be made at the preliminary design stage. The choice of blade loading is of particular concern in the low pressure (LP) turbine of civil aero engines, where the use of high-lift blades is widespread. This paper considers how blade loading should be measured, compares the performance of various loss correlations, and explores the impact of blade lift on performance and lapse rates. To these ends, an analytical design study is presented for a repeating-stage, axial-flow LP turbine. It is demonstrated that the long-established Zweifel lift coefficient (Zweifel, 1945, "The Spacing of Turbomachine Blading, Especially with Large Angular Deflection" Brown Boveri Rev., 32(1), pp. 436-444) is flawed because it does not account for the blade camber. As a result the Zweifel coefficient is only meaningful for a fixed set of flow angles and cannot be used as an absolute measure of blade loading. A lift coefficient based on circulation is instead proposed that accounts for the blade curvature and is independent of the flow angles. Various existing profile and secondary loss correlations are examined for their suitability to preliminary design. A largely qualitative comparison demonstrates that the loss correlations based on Ainley and Mathieson (Ainley and Mathieson, 1957, "A Method of Performance Estimation for Axial-Flow Turbines," ARC Reports and Memoranda No. 2974; Dunham and Came, 1970, "Improvements to the Ainley-Mathieson Method of Turbine Performance Prediction," Trans. ASME: J. Eng. Gas Turbines Power, July, pp. 252-256; Kacker and Okapuu, 1982, "A Mean Line Performance Method for Axial Flow Turbine Efficiency," J. Eng. Power, 104, pp. 111-119). are not realistic, while the profile loss model of Coull and Hodson (Coull and Hodson, 2011, "Predicting the Profile Loss of High-Lift Low Pressure Turbines," J. Turbomach., 134(2), pp. 021002) and the secondary loss model of (Traupel, W, 1977, Thermische Turbomaschinen, Springer-Verlag, Berlin) are arguably the most reasonable. A quantitative comparison with multistage rig data indicates that, together, these methods over-predict lapse rates by around 30%, highlighting the need for improved loss models and a better understanding of the multistage environment. By examining the influence of blade lift across the Smith efficiency chart, the analysis demonstrates that designs with higher flow turning will tend to be less sensitive to increases in blade loading. © 2013 American Society of Mechanical Engineers.

Programmable ZnO nanowire transistors using switchable polarization of ferroelectric liquid crystal

We demonstrate modulations of electrical conductance and hysteresis behavior in ZnO nanowire transistors via electrically polarized switching of ferroelectric liquid crystal (FLC). After coating a nanowire channel in the transistors with FLCs, we observed large increases in channel conductance and hysteresis width, and a strong dependence of hysteresis loops on the polarization states associated with the orientation of electric dipole moments along the direction of the gate electric field. Furthermore, the reversible switching and retention characteristics provide the feasibility of creating a hybrid system with switch and memory functions. © 2013 American Institute of Physics.

长江天鹅洲故道江豚的集群规模及其时空分布

2 0 0 1年 5月至 2 0 0 2年 4月 ,选择使用岸上定点观察、流动观察和水上流动观察 3种观察方式 ,对长江天鹅洲故道内约 2 0头江豚的集群状况进行了一个周年的监测 ,共观察到江豚集群 5 88次。结果表明 :天鹅洲故道内江豚以集群的方式迁移和活动 ,集群规模从 2— 2 0头不等 ,一般分成 2个 9— 11头规模的亚群体 ,2个亚群体活动范围相对独立 ,其活动主要为D区和H区。每个亚群体又常分成规模较小的核心群体 ,其中 3头集群最多。一年中春、秋和冬季江豚集群状况基本相同 ,而夏季有所

中国胭脂鱼种群的遗传分析

采用RAPD和PCR RFLP技术 ,分析了长江中游两个中国胭脂鱼群体的遗传结构。 50个随机引物进行RAPD分析 ,有 3个引物显示了多态 ,宜昌、金口群体内个体之间的遗传相似度分别为 0 .92 74、0 .931 3 ,群体之间遗传相似度为 0 .90 0 0。 1 2个限制性内切酶分析了两群体线粒体DNAND - 5/ 6基因的限制性片段长度多态性 ,仅内切酶Ncil的酶切图谱显示了多态 ,基因型间的核苷酸序列歧化距离为 0 .2 35 % ,核苷酸多样性为 0 .0 0 4。分析表明 ,长江中游