流导可控的AAO分子流漏孔的制作与动态测试

随着分子流漏孔的广泛应用, 迫切需要一种制作简单、成本低廉且流导可控的分子流漏孔制作方法。本文基于阳极多孔氧化铝 (AAO) 模板, 利用打孔硅片作为掩膜和支撑材料, 制作出不同有效面积的AAO新型分子流漏孔, 然后使用自主设计的动态差压法漏孔测量设备, 以氮气、氦气和氩气作为测试气体对所制作的直径分别为2和13 mm圆形AAO分子流漏孔流导进行了测量。实验结果表明, 漏孔的流导测量值接近理论计算值, 流经AAO漏孔的气体始终保持分子流状态, 即流导维持不变。AAO分子流漏孔具有制备工艺简单、成本低、流导可控且可预测不同种类气体流导等优点。     

热流逸效应下不同截面形状微通道的流导特性分析

热流逸真空泵利用其内部微通道结构产生的热流逸效应来工作,故其本身也存在流导。本文建立了几种典型截面形状长微通道和短微通道的流导计算模型,进而分析了流导随努森数、温差及微通道特征尺寸变化的规律。结果表明,微通道在过渡流区域的流导比在自由分子流区域的大2~4个数量级;短微通道的流导性能优异长微通道的;绝大多数情况下,截面形状的对称性越强则其流导性能越好;在自由分子流区域,截面形状对流导的影响不大,但在过渡流区域,不同截面形状的流导差异显著。可见,应尽可能将热流逸真空泵设计在过渡流区域工作,且应优先采用截面形状对称性强的短微通道结构,但需要综合考虑努森数、温差和微通道特征尺寸之间的相互协同与制约。     

Estimation of the bacteriological quality of fish by automated conductance measurements

The rapid automated conductance assay system has been used in experiments concerned with estimating the bacteriological quality of fish in terms of total and selective counts. Results of the former method were obtained in one-fifth of the time taken by conventional methods and the correlations between the methods were good. Selective counts of Escherichia coli, coliforms, and vibrios were completed in one-third of the normal time. The instruments were easy to use and the results easy to interpret. The method holds out good promise for automating such routine fish bacteriology.     

The control and maintenance of desired flow patterns in bends of different orientations

Multiphase flows are common in industrial settings and bends in pipe lines cannot be avoided due to space limitations. Gas-liquid two phase flows could form material discontinuities that could have adverse effect on productivity and the pipe network due to sudden variations resulting due to the rapid momentum flux variations at fittings such as bends. Research into gas-liquid flow and bends can be motivated by the effect of the bend on the flow downstream of it which could alter the flow pattern occurring and the performance of downstream equipment. Alternatively, the interest might come from what occurs in the bend itself, there could be dryout of the film on the walls and consequent damage to the heat transfer equipment. Here we present measurements made with a number of accurate and fast responding sensors on three cases, two on the effect of the bend and one considering effects in the bend. The results show that the flow transformations occur in two phase flows depending on the orientation of the bend and the change could be captured using fast sweeping measurement techniques. We present the evidence of effectiveness of several types of measurement techniques that could fit into various combinations of phases. The results, point to how to achieve certain flow patterns. Also recommendations are provided regarding the position of any sensor installed to determine flow pattern.     

On the dependence of the Nernst diffusion layer thickness on potential and sweep rate for reversible and of the thickness of the charge transfer layer for irreversible processes studied by application of the linear potential sweep method

In this paper, a discussion is made of the dependence between the diffusion layer thickness and the potential sweep rate and the potential value for reversible charge transfer processes studied under the application of a linear potential sweep. Also the equivalent circuit for that type of processes is remembered as well as the concept of conductance. The same concepts are discussed for the case of irreversible charge transfer processes studied also by linear potential sweep voltammetry. A consideration is made of the concept of general conductance as utilised in electrochemical processes and the results of its utilisation are compared with those obtained by using the physical definition of conductance and discussed.     

交联甲基丙烯酸甲酯/丙烯酸共聚微球羧基分布研究

用分散聚合法制备了交联甲基丙烯酸甲酯/丙烯酸(PMMA/AA)共聚微球,以电导滴定法研究了不同聚合反应条件对微球不同区域羧基分布的影响。研究结果表明增大配方中丙烯酸浓度或引发剂浓度,表面结合与被包埋的羧基含量增大,游离羧基含量降低;提高反应温度,表面结合羧基含量减小,被包埋的与游离羧基增大。 采用分散聚合法制备了交联甲基丙烯酸甲酯/丙烯酸(PMMA/AA)共聚微球,以电导滴定法研究了不同聚合反应条件对微球不同区域羧基分布的影响。研究结果表明增大配方中丙烯酸浓度或引发剂浓度,表面结合与被包埋的羧基含量增大,游离羧基含量降低;提高反应温度,表面结合羧基含量减小,被包埋的与游离羧基增大。     

全无油往复真空输送泵泄漏分析及计算

本文分析了输送泵的泄漏途径及泄漏对输送泵性能的影响，探讨了曲轴箱的压力、运用流导的方法计算了通过活塞环的泄漏量，并进行了结果分析。     

中石油某国外项目油田地面工程含盐分析

简要介绍了国际标准中原油盐含量测定的两种方法 ASTM D3230与ASTM D6470,并对比了两种国际标准的优缺点。概括了在线分析仪在石油化工领域的应用,并重点介绍了瑞士万通ADI 2045在线原油盐分分析仪在中石油某国项目上的成功应用。在线含盐分析仪在油田工程中的推广应用可优化资源利用,实现自动化产业升级,前景广阔。     

Evaluation of the film formation and the charge transport mechanism of indium tin oxide nanoparticle films

The structure formation and charge transfer of thin nanoparticulate indium tin oxide (ITO) films prepared by dip-coating was studied as a function of stabilizer before and after annealing at different temperatures. The analysis of the film structure by optical methods revealed that it is a function of the stability. Suspensions containing an optimum stabilizer concentration of 0.1 mol/l resulted in densely packed films with a peak specific conductivity of 8.3 S cm^− 1 after annealing at 550 °C for 1 h in air and 121 S cm^− 1 after annealing in forming gas at 250 °C for 1 h, respectively. Furthermore, for the densely packed films fluctuation-induced tunnelling was found to be the dominant charge transport mechanism, whereas for the low density films a thermally activated charge transport was observed. That the films of maximum density showed a metallic charge transport behaviour at temperatures above 300 K indicated the optimal contact between ITO particles had been achieved.