场助纳米二氧化钛薄膜光催化降解甲紫的研究

纳米二氧化钛是一种重要的无机功能材料。本文采用溶胶-凝胶法制备了TiO_2薄膜,利用"场助"影响其光催化特性。光催化实验以可能具有致癌性并且难以生化降解的三苯甲烷类染料——甲紫作为降解物质,用2100型分光光度计来测量降解率,以确定电场、磁场强度对光催化特性的影响。光催化实验结果表明,外加电场(未参与水的电解)、磁场对于协助光催化降解甲紫有着明显的效果。随着外加电场、磁场强度的增加,甲紫溶液的降解率有大幅提高。反应符合一级动力学方程。     

一种基于Markov随机场模型的核磁共振图像分割方法

为了提高核磁共振(MR)图像分割的效果,提出了一种基于Markov随机场模型的分割方法。该方法利用Markov随机场描述图像的先验分布,结合MAP准则获得分割优化函数,通过ICM局部迭代使分割优化函数收敛。迭代过程中引入了后验概率矩阵的平滑;提高了分割的精度和速度。实测数据的实验结果证明了所提方法的有效性。     

电子封装热应力数值分析

针对目前电子封装的封装密度越来越高、封装厚度越来越薄、封装体在基板上所占面积越来越大,发热引起的失效越来越严重等问题,以晶体管瞬态热应力分析为例,建立热力耦合力学模型.利用ansys研究电子封装热失效问题,得到温度场、应力场和变彤场的分布规律.温度和应力的主要规律包括两点,一是温度和应力都在角点处变化明显,应力比较集中.温度从上到下逐层变化,逐渐减小,并且层与层之间温度变化不大,模型中间部分温度层厚度几乎相同,下半部分同一温度层有规律的变化.二是当温度较高时,在受约束面上和角点处应力值较大,并且在模型的角点和中部出现应力集中现象.     

壳体辐射物性参数对平流层飞艇热特性影响的研究

建立了飞艇的传热数学模型,包括热平衡方程,太阳直射辐射、天空散射辐射、地面反射辐射、大气长波辐射、地球长波辐射、对流换热,以及飞艇内表面之间的辐射换热等。在此基础上,对平流层飞艇悬浮过程中壳体和浮升气体的温度变化进行了数值模拟,得到定点悬浮过程中平流层飞艇壳体的三维温度分布和飞艇浮升气体昼夜变化规律,重点分析了壳体辐射物性（太阳吸收率和发射率）对浮升气体温度昼夜变化和飞艇壳体温度分布非均匀性的影响,从而便于计算和分析由热问题引起的壳体应力,为飞艇壳体的选择和设计提供依据。     

New and little-known species of Didemnidae (Ascidiacea,Tunicata) from Australia (part I)

Continuing examination of colonial ascidians in museum collections is revealing further diversity in the family Didemnidae, which abounds in the tropical Indo-West Pacific and around the Australian continent (Kott, 2001). From the present work, it is apparent that much remains to be learnt about this fauna. Of the 45 species discussed in this paper, 16 are new. Larvae are described for the first time for Polysyncraton pedunculatum Kott, 2001 and P. rica Kott, 2001. Amongst the synonymy established in this paper Didemnoides tropicum Sluiter, 1909 is found to be a junior synonym of Lissoclinum patella (Gottschaldt, 1898) and Trididemnum vermiforme Kott, 2001 a junior synonym of T. nobile Kott, 2001. Didemnum nekozita Tokioka, 1967 is found to be a valid species distinct from Polysyncraton cuculliferum (Sluiter, 1909). Prolific replication rates, rapid colony growth, flexibility in growth form and a viviparous habit result in convergence tending to small zooid size, and similar large, increasingly complex colonies found in this family contribute to species diversity around the whole of the Australian continent.     

电信空调冷却塔供冷系统节能应用

根据电信机楼的空调负荷特点,在冬季和部分过渡季节,选择使用冷却塔加板式换热器的间接式免费供冷空调系统为电信机楼提供冷量。介绍了冬季机房空调送风温度和冷却塔供冷温度的确定,分析了冷却塔供冷温度对冷却塔运行消耗的影响。通过预测计算确定冷却塔免费制冷的的运行时间及节能效果。并引入了冷负荷供需指数的概念,经过现场测试计算得出江苏电信第二枢纽工程中影响该指数的三个因素,最后总结了江苏电信免费制冷技术的节能情况和应用潜力。     

温度对煤吸附瓦斯特性影响的实验研究

为了研究温度对煤吸附瓦斯特性的影响对于深部高温瓦斯矿井进行通风设计及煤层气资源评价的指导意义,利用瓦斯吸附装置,对不同煤样进行不同温度下吸附等温线及吸附常数的测定。实验表明：吸附常数b与温度T较好的符合负指数关系;而随着温度的升高,吸附常数a值变化不大,可以认为是某一恒定值。     

Microhabitat selection in the sand recluse spider (Sicarius thomisoides): the effect of rock size and temperature

In spiders, temperature is considered an important environmental variable for microhabitat selection. In this study, we evaluated the effect of temperature and rock size on the presence of the sand recluse spider Sicarius thomisoides and the degree of selectivity in different locations. This species is a large spider that lives under rocks in desert and semi-desert climates and is particularly active during the summer. In Chile, these spiders can be found at both coastal and inland locations under different thermal conditions, where usually the temperatures are lower near the coast. If large-scale climatic conditions are important for this species, they may be expected to select lower rock temperatures on the coast than at inland locations. In addition, we would expect that the spiders would choose larger rocks in inland compared to coast locations, which reduce the effect of high temperatures. We found that the probability of finding individuals of this species increased according to rock temperature and rock size in the field. Our results suggest that S. thomisoides prefers larger and warmer rocks to shelter under during the day, this selectivity being similar at both coastal and inland locations. Thus, this species tends to select rocks with the same thermal and structural conditions, independent of the climatic conditions.     

Mortality effects of temperature changes in the United Kingdom

Temperature changes are known to affect the social and environmental determinants of health in various ways. Consequently, excess deaths as a result of extreme weather conditions may increase over the coming decades because of climate change. In this paper, the relationship between trends in mortality and trends in temperature change (as a proxy) is investigated using annual data and for specified (warm and cold) periods during the year in the UK. A thoughtful statistical analysis is implemented and a new stochastic, central mortality rate model is proposed. The new model encompasses the good features of the Lee and Carter (Journal of the American Statistical Association, 1992, 87: 659–671) model and its recent extensions, and for the very first time includes an exogenous factor which is a temperature‐related factor. The new model is shown to provide a significantly better‐fitting performance and more interpretable forecasts. An illustrative example of pricing a life insurance product is provided and discussed.     

有限元法在电机温度场仿真中的运用

运行的超声电机会产生温升,过高的温升对超声电机的机械特性及使用寿命都有较大影响。本文首先通过实验证明压电陶瓷元件发热和摩擦层摩擦发热是超声电机温升的主要热源;然后,分别以压电陶瓷元件发热和摩擦层摩擦发热为热源,建立其相应的温度场热分布模型。并用有限元软件分别对压电陶瓷元件发热场和接触摩擦发热场进行仿真计算。计算结果表明,压电陶瓷片发热源部分,热量最大处为压电陶瓷片粘贴面的内圈;接触摩擦发热中,摩擦产生的热量集中在接触表面。