The Effect of Conical Flowfields on the Performance of Waveriders at Mach 6

The performance of 23 kinds of waveriders, derived from different conical flowfields, is analyzed by the numerical computation under the conditions of fight speed of Mach 6, attack angle of 0° and flight altitude of 30 km. These results indicate that the performance is influenced by the shapes and the width to height ratios (W/H ) of generating cones. The geometrical parameter and the lift coefficient are proportional to W/H, while the drag coefficient and the lift to drag ratio (L/D ) have extreme values. Considering the base drag and the computation errors, the waverider with the highest L/D is cut from the elliptical cone’s flowfield (W/H = 1.5―1.618), and the configuration with the lowest drag can also be obtained at W/H = 1:1.5. Accordingly, good suggestions are proposed for practical design based on these computational results.

Magnetostatic equilibrium of isolated magnetic-flux tube

In the present paper, an isolated axisymmetric flux tube is discussed for slender magnetic configuration. The magnetostatic model and the stratified atmospheric model are applied, respectively, to the regions inside and outside the flux tube. The problem is described mathematically by the nonlinear partial differential equations under the nonlinear boundary condition at the free boundary of flux tube. According to the approximation of a small expansive angle, the solutions of series expressions are obtained formally. The model of polytropic plasma is discussed in detail especially. The results show the distributions of thermodynamic quantities and magnetic field extending from the high β region to the low β region, and the flux tube may be either divergent or convergent according to the pressure difference outside and inside the flux tube.

环境介质对40Cr结构钢高周和超高周疲劳行为的影响

选用40Cr结构钢,分别在空气、水和3.5%NaCl水溶液中进行旋转弯曲疲劳实验,研究环境介质对该结构钢高周和超高周疲劳特性的影响.结果表明,40Cr钢在水环境中的疲劳强度比在空气中明显降低;在3.5%NaCl水溶液环境中的疲劳强度比在水中低.断面观察显示,在水和3.5%NaCl水溶液中,疲劳裂纹多源萌生;在稳态扩展阶段,裂纹沿晶界扩展并存在广泛分布的沿晶二次裂纹.

高精度微结构聚合物光栅的复制技术

光栅复制是降低光栅制造成本,提高产量的一条有效途径。研究了利用紫外压印技术复制微结构光栅的方法。使用玻璃基底矩形浮雕结构的微结构光栅作为母光栅,给出了利用聚二甲基硅氧烷(PDMS)制作光栅模具和在光敏聚合物材料上复制微结构光栅的详细过程。经过优化工艺条件,成功地复制了一系列不同周期和开口比的微结构光栅,测试了复制光栅和母光栅的衍射图像和0级与±1级的衍射强度,结果表明,复制光栅和母光栅的衍射图像与光强分布基本一致。

放牧与围栏羊草草原土壤呼吸作用研究

基于静态箱式法，在内蒙古典型羊草草原围栏与自由放牧样地对土壤呼吸作用及其影响因子进行连续两年野外对比观测。结果表明，围栏内外土壤呼吸作用的日、季动态差异不大，日动态呈单峰型曲线，高峰值一般出现在午间11：0014：00，最低值出现在凌晨1：003：00。从整个生长季节来看，土壤呼吸作用的最大值出现在6月中旬到7月底，随后逐渐降低。整个观测期间围栏与放牧样地土壤呼吸作用平均值分别是219.18 mg CO2•m-2•h-1和111.27 mg CO2•m-2•h-1，围栏样地土壤呼吸作用明显高于放牧样地，可能与土壤含水量改善和生物量增加有关。对影响土壤呼吸作用的因子分析表明，放牧使土壤含水量和相对湿度明显降低，而对气温、大气CO2浓度和光合有效辐射的影响并不大，且放牧使羊草净光合速率的影响明显增加，而对气孔导度和胞间CO2浓度影响不大。围栏样地土壤呼吸作用与各影响因子的相关性从大到小依次为土壤含水量、净光合速率、气温、相对湿度、大气CO2浓度、胞间CO2浓度、气孔导度和光合有效辐射，其中土壤含水量和气温是影响土壤呼吸作用的主要环境因子，净光合速率是主要的生物因子。尽管放牧改变了土壤呼吸速率，但土壤呼吸作用各影响因子的排列顺序基本上没有改变,只是发生了量的变化。选择目前常用的土壤呼吸作用水热因子模型，在放牧与围栏羊草草原分别进行了验证和评估。在低温低湿条件下，土壤呼吸作用主要受温度调控，然而，随着温度升高和水分增加，温度单因子模型不能模拟水分对土壤呼吸作用的激发作用。在干旱半干旱的典型草原区，土壤呼吸作用主要受土壤含水量影响，而如果把温度的调控作用考虑进去能进一步提高模型的预测能力。在围栏样地，水热双因子线性模型的相关系数高于其它模型，可以解释土壤呼吸作用82%以上的变化情况，而对于放牧样地来说，指数模型、指数-乘幂模型和指数-Arrhenius方程的相关系数(R2=0.87-0.88)高于线性模型(R2=0.73-0.79)。 在温室实验中，通过模拟典型草原优势植物种羊草不同密度对土壤呼吸作用的影响，采用根系生物量梯度外推法对羊草种群根呼吸作用与微生物呼吸作用进行了区分。结果表明，羊草根系呼吸速率在生长初期最大, 达到33.5 mg CO2•gDW-1•h-1, 随着植物生长逐渐降低而趋于稳定, 在1.1~2.0 mg CO2•gDW-1•h-1之间变动。整个生长季节根呼吸作用占土壤呼吸总量比例从9.7%逐渐上升到52.9%，平均值为36.8%。尽管随着生长根呼吸速率逐渐降低, 但根系生物量的增加却使根呼吸作用所占比例不断升高。

大蹼铃蟾抗菌肽- 2 与IFN2α22b 和TNF2α对膀胱癌细胞株抑制活性的实验研究

目的:比较大蹼铃蟾抗菌肽- 2 (Maximin 2) 与肿瘤坏死因子2α(TNF2α) 、干扰素2α22b ( IFN2α22b) 对不同膀胱癌细胞株的抑制杀伤作用。方法:采用细胞培养及MTT 比色法,检测Maximin 2 、TNF2α及 IFN2α22b 对3 个不同膀胱癌细胞株的抑制作用及作用特点,计算量效回归曲线及50 %抑制率。结果: Maximin 2 对不同的膀胱癌细胞株在100μgPmL 左右(48 h) 即达到50 %抑制率浓度( IC50) ,并呈剂量相 关性,与TNF2α、IFN2α22b 抑制作用的表现形式不同。Maximin 2 抑制率最高表现在第48 h ,以后逐渐减 弱, TNF2α、IFN2α22b 则在前24 h 作用较弱,以后逐渐增强。结论:Maximin 2 对不同的膀胱癌细胞株均 有较强的抑制作用,同TNF2α、IFN2α22b 比较其作用机制有所不同,Maximin 2 对膀胱癌细胞株的杀伤作 用可能主要是通过对肿瘤细胞的直接抑制,并且相对容易失活。

母鸡输卵管子宫部初级感觉神经元的CB-HRP法定位研究

应用CB-HRP溶液注入母鸡输卵管子宫部浆膜下,四甲基联苯胺(TMB)组织化学呈色,以探察母鸡输卵管子宫部初级感觉神经元的定位。结果表明:母鸡输卵管子宫部的初级感觉神经元位于双侧T1-LS13脊神经节、颈静脉神经节和结状神经节。标记细胞数分布不均,在体左侧多于体右侧,在脊神经节多于颈静脉神经节和结状神经节。在脊神经节内标记细胞有T5-LS1和LS8-LS11前后两个相对集中区,峰值分别在T7和LS11。说明尽管母鸡输卵管子宫部是单侧发育成熟脏器,但其感觉沿双侧脊神经和迷走神经传入中枢,以体左侧传入为主;且

Web Services Workflows—Composition, Co-Ordination, and Transactions in Service-Oriented Computing

Web services can be seen as a newly emerging research area for Service-oriented Computing and their implementation in Service-oriented Architectures. Web services are self-contained, self-describing modular applications or components providing services. Web services may be dynamically aggregated, composed, and enacted as Web services Workflows. This requires frameworks and interaction protocols for their co-ordination and transaction support. In a Service-oriented Computing setting, transactions are more complex, involve multiple parties (roles), span many organizations, and may be long-running, consisting of a highly decentralized service partner and performed by autonomous entities. A Service-oriented Transaction Model has to provide comprehensive support for long-running propositions including negotiations, conversations, commitments, contracts, tracking, payments, and exception handling. Current transaction models and mechanisms including their protocols and primitives do not sufficiently cater for quality-aware and long running transactions comprising loosely-coupled (federated) service partners and resources. Web services transactions require co-ordination behavior provided by a traditional transaction mechanism to control the operations and outcome of an application. Furthermore, Web services transactions require the capability to handle the co-ordination of processing outcomes or results from multiple services in a more flexible manner. This requires more relaxed forms of transactions—those that do not strictly have to abide by the ACID properties—such as loosely-coupled collaboration and workflows. Furthermore, there is a need to group Web services into applications that require some form of correlation, but do not necessarily require transactional behavior. The purpose of this paper is to provide a state-of-the-art review and overview of some proposed standards surrounding Web services composition, co-ordination, and transaction. In particular the Business Process Execution Language for Web services (BPEL4WS), its co-ordination, and transaction frameworks (WS-Co-ordination and WS-Transaction) are discussed.

吸收压缩复合式热泵及制冷技术

本文概述了吸收压缩复合式热泵及制冷技术的发展现状和最新研究结果，着重论述了这种新兴能量转换技术的构成方式和特点，以及该技术的优越性能、经济性和应用前景。表明这种复合式逆向能量转换技术必将在制冷空调行业以及能量回收再利用领域扮演不可缺少的重要角色。

Corrosion inhibition of carbon steel in tetra-n-butylammonium bromide aqueous solution by benzotriazole and Na3PO4

The corrosion inhibition behavior of benzotriazole, Na3PO4 and their mixture on carbon steel in 20 wt.% (0.628 mol l(-1)) tetra-n-butylammonium bromide aerated aqueous solution was investigated by weight-loss test, potentiodynamic polarization measurement, electrochemical impedance spectroscopy and scanning electron microscope/energy dispersive X-ray techniques. The inhibition action of BTA or SP or inhibitors mixture on the corrosion of carbon steel is mainly due to the inhibition of anodic process of corrosion. The results revealed that inhibitors mixtures have shown synergistic effects at lower concentration of inhibitors. At 2 g l(-1) BTA and 2 g l(-1) SP showed optimum enhanced inhibition compared with their individual effects.