个性心理特征与干部的考核任用

个性心理特征是人的气质、性格和能力的集中体现。在干部的考核任用工作中,既要为每个岗位选择最合适的干部,又要为每个干部找到最合适的岗位。要使干部的聪明才智与学识技能在工作中得以充分的发挥,就必须重视考察测评干部的个性心理特征。     

虾夷扇贝的摄食生理及其在獐子岛海域的群体滤水能力

为了獐子岛海域虾夷扇贝养殖容量评估模型的建立,采用模拟现场流水系统和生物沉积方法测定了不同规格虾夷扇贝在不同季节的滤水率（CR）、摄食率和吸收效率,并探讨了温度与滤水率的关系.通过断面生物量调查,获得该海域虾夷扇贝的壳高频率分布情况.结果显示,5月份虾夷扇贝的滤水率最大.其它3个月份虾夷扇贝的滤水率差异不显著,10月份的吸收效率最低.温度（T）与滤水率（CR）呈抛物线的关系,在本实验的条件下,虾夷扇贝摄食的最适温度为10 ℃.滤水率与壳高呈典型的幂函数关系.根据滤水率与壳高的关系、獐子岛海域养殖虾夷扇贝的壳高频率分布情况以及总生物量,推算出不同月份的群体滤水能力,结合獐子岛的潮差、水面面积等数据,计算出其在该海域的食物限制性指标--清滤效率.结果显示:目前獐子岛养殖虾夷扇贝的清滤效率平均为0.054<1,虾夷扇贝的养殖量低于养殖容量,在养殖密度和规模上,尚有很大的发展空间.     

贵阳市紫林庵路口通行能力分析及改进措施

作者以目前贵阳市紫林庵信号环形交叉口为例,通过对此路口高峰时段交通量调查及相关数据采集,对该交叉口的通行能力进行分析和计算.再假设在其它相关数据不变的基础上,分析和计算将现在的信号环形交叉口改为信号平面直交口的通行能力.将两者进行比较和评价,得出信号平面直交口的设计通行能力比信号环形交叉口的设计通行能力更大,更能缓解该地区高峰时段交通拥堵状况.由此得到将现有的环形交叉口改为平面直交口的方案是合理可行的.     

天然红树林湿地对河水中溶解性磷酸盐的净化作用初探——以广州市南沙开发区为例

以广州市为数不多的天然红树林湿地之一,南沙开发区内珠江火电厂下游珠江狮子洋河段西南岸以及槽船村内河道水闸下游两个区域的天然红树林湿地沿途的溶解性磷酸盐含量变化的实测数据为依据,研究天然红树林湿地对磷的净化作用。河道内红树林不同覆盖宽度区之间和不同河道之间溶解性磷酸盐含量的对比分析显示红树林湿地对水体中的溶解性磷酸盐具有很强的净化能力,河岸红树林湿地的过滤作用的大小与河岸红树林占据河道面积的大小有关,同等河宽条件下,红树林植物覆盖宽度越大其净化能力越大。     

TiO2纳米管的改性及光助催化性能研究

利用水热法制备了两种TiO2纳米管催化剂,用不同浓度硫酸对制备得到的TiO2纳米管进行酸化。结合XRD、SEM、TEM、DRS等手段对制备得到的样品进行物理结构和表面特性分析。结果表明,水热法制备得到的TiO2纳米管径为15nm左右,壁厚2—3nm,长度为40-100nm。以酸性橙Ⅱ为目标物考察了TiO2纳米管及其被硫酸酸化过的TiO2纳米管在石英玻璃反应器的光催化氧化性能。结果表明,在相同的条件下酸化的TiO2纳米管催化活性要远远高于未酸化的TiO2纳米管,这可能是因为S—O键具有很强的诱导效应,使得表面Ti^4＋的Lewis酸性增强,使光生电子一空穴对的分离效率提高,促进光催化反应的进行,即提高了TiO2纳米管的光催化性能。     

基于有序Logistic回归模型的北京高校男生有氧能力

为探索北京高校男生有氧能力的影响因素,通过随机抽样法抽取134名18~25岁北京高校男生,空腹抽静脉血测血液指标,用德国MetaMax 3B系统实时监测气体代谢,通过线性递增方案测得VO2max相对值。基于Spearman相关、有序Logistic回归等分析方法进行分析处理。结果表明：北京高校男生有序Logistic回归方程：Ln{P(Y≤1|x)/1-P(Y≤1|x)}=-2.757-0.067*X1-0.025*X2+0.066*X3+0.018*X4-0.009*X5;Ln{P(Y≤2|x)/1-P(Y≤2|x)}=-0.771-0.067*X1-0.025*X2+0.066*X3+0.018*X4-0.009*X5（X1=体重、X2=心率(heart rate, HR)、X3=每搏输出量(stroke volume, SVI)、X4=心室射血时间(ventricular ejection time, VET)、X5=血红蛋白(hemoglobin, HGB)）。回归方程模型系数综合检验步(step)、块(block)、模型(model)检验的P值均小于0.01;拟合优度检验的-2对数似然值(-2LL)为159.374,Cox&SnellR2为0.331,NagelkerkeR2为0.373;预测等级1准确率为45.5%,等级2准确率为100%,等级3准确率为100%,综合为81.8%,说明Logistic回归模型性能良好。Hosmer和Lemeshow检验预测值与观望值无显著性差异（P>0.05）。可见北京高校男生定量负荷心功能、血液指标与有氧能力的多元Logistic回归模型拟合度较好,且HR、SVI、VET、HGB是有氧运动能力的重要预测因素。     

Flow and heat transfer behaviour of nanofluids in microchannels

Flow and heat transfer of aqueous based silica and alumina nanofluids in microchannels were experimentally investigated. The measured friction factors were higher than conventional model predictions at low Reynolds numbers particularly with high nanoparticle concentrations. A decrease in the friction factor was observed with increasing Reynolds number, possibly due to the augmentation of nanoparticle aggregate shape arising from fluid shear and alteration of local nanoparticle concentration and nanofluid viscosity. Augmentation of the silica nanoparticle morphology by fluid shear may also have affected the friction factor due to possible formation of a core/shell structure of the particles. Measured thermal conductivities of the silica nanofluids were in approximate agreement with the Maxwell-Crosser model, whereas the alumina nanofluids only showed slight enhancements. Enhanced convective heat transfer was observed for both nanofluids, relative to their base fluids (water), at low particle concentrations. Heat transfer enhancement increased with increasing Reynolds number and microchannel hydraulic diameter. However, the majority of experiments showed a larger increase in pumping power requirements relative to heat transfer enhancements, which may hinder the industrial uptake of the nanofluids, particularly in confined environments, such as Micro Electro-Mechanical Systems (MEMS).     

Effect of heat treatment on microstructures and properties of a novel Al-Zn-Mg-Cu alloy for oil drilling

In view of the special requirements for strength, heat resistance and corrosion resistance of Al-Zn-Mg-Cu alloy for oil drilling, the Al-6.2 Zn-2.5 Mg-1.6 Cu alloy was prepared by increasing Cu content on basis of Russian Series 1953 alloy. The effect of heat treatment on the microstructures and properties of the alloy was characterized by optical microscope(OM), scanning electron microscope(SEM) and transmission electron microscope(TEM), and investigated by tensile test at room temperature, thermal exposure test and corrosion test. The results show that the strength after T6 aging treatment exhibit a decrease trend as an increase of the solution temperature from465 °C to 480 °C. After the solution treated by the rate of 470 °C/1 h, second phases dissolve into the matrix very well and the strength property reaches optimum. The alloy has better comprehensive properties treated by a solution treatment of 470 °C/1 h and then followed by an aging treatment of 120 °C/24 h + 170 °C/1 h + 120 °C/24 h. Under the aging state, the precipitated phases inside the grains are suitable in size, while on the grain boundary distribute discontinuously and the precipitate-free zone is obvious. Besides, the alloy still maintain high tensile properties. The yield strength, tensile strength and elongation are 650 MPa, 686 MPa,12.0%, respectively. The yield strength retention after heat exposure is 92%. The alloy has good corrosion resistance and the exfoliation corrosion degree. The average corrosion rate in the H_2S and CO_2 environment is 0.0024 mm/a, which is far less than the required 0.12 mm/a. It is insensitive to H_2S and CO_2 environments.     

层板发汗冷却数学模型与控制方程的求解

本文描述了结构层板与冷却剂相互之间存在温差的发汗冷却计算模型,导出了层板发汗冷却控制方程。对定常控制方程的积分求解方法和超临界状态非定常控制方程的数值求解方法进行了探讨,例举了液体火箭发动机推力室壁采用液氧作为冷却剂的计算结果。计算结果表明,基本模型符合实际的物理过程,求解过程直观简捷。由于冷却机理的类似,其数学模型与计算方法也适用于多孔材料等其它形式的热控制装置的发汗冷却研究。