四元混合可燃液体闪点的测定

闪点是指在稳定的空气环境中,加热试样,可燃性液体或固体表面产生的蒸汽在试验火焰作用下被闪燃时的最低温度。本文利用闪点测定仪对松节油、丁酮、乙酸丁酯、甲醇通过实验在不同的情况下所组成四元的混合液体闪点的变化进行的研究,并以此推算出四元混合液体闪点在规定的实验条件下,随配比改变而变化的经验公式,并讨论了公式的实用范围。     

三元混合可燃液体闪点研究

闪点是指在一稳定的空气环境中,可燃性液体或固体表面产生的蒸气在试验火焰作用下被闪燃时的最低温度。利用闪点测定仪对三元醇类混合、三元醚类混合、醇醚混合等不同情况下混合易燃液体的闪点变化规律进行了实验研究,推算出了三元混合易燃液体在规定实验条件下闪点随配比变化的闪点估算公式,并且对混合易燃液体的闪点变化规律进行了分析。     

自制简易虹吸杯

虹吸现象是指在大气压强和液体压强作用下产生的液体流动现象.如图1所示,由于细管两个端口处承受的压强不同,液体会从压强大的一边流向压强小的一边,直到两边压强相等.利用虹吸现象可以快速将容器内的水抽出.     

浅谈透层油施工容易出现的问题、原因及预防措施

透层是使沥青面层与非沥青材料基层结合良好,在基层上浇洒乳化沥青、煤沥青或液体沥青而形成的透入基层表面的薄层。本文主要阐述透层的作用及机理、透层施工中容易出现的问题、原因分析及预防措施。     

绝缘性矿物油中和时间测试方法的研究与实验

液体在和固体壁面相对运动时会产生流动带电现象,当液体为高阻抗的绝缘性液体时,其所携带的电荷将缓慢的进行中和,其中和时间对于静电的释放关系重大。本文在分析绝缘性液体的中和特性的基础上,通过普通的运算放大器,测出绝缘性矿物油VG46的中和时间,提出并验证其中和时间是以指数曲线进行衰减,并为高阻抗矿物油流动带电的测试和中和时间提供一种测试方法。     

离子液体在高效液相色谱分析中的应用进展

本文主要从流动相添加剂、固定相两个方面综述了离子液体在高效液相色谱分析中的应用进展。     

溶液除湿空调系统研究分析

本文主要介绍了温湿度独立控制的溶液除湿空调系统的工作过程,通过对驱动热源的主要来源,整个空调系统的影响因素的分析,明确今后发展和改进方向,针对不同环境选择合适的除湿、再生系统以及液体吸湿剂。     

人才资源国际流动的趋衡性分析

随着经济全球化进程的加快,各国间的人才资源流动不断加剧。人才资源国际流动对于不同国家之间和不同时间区间的情况是不同的,是一个复杂的过程。本文假设在全球范围人才资源自由流动的市场条件下,从宏观上定性研究人才资源国际流动的趋衡性,对人才资源国际流动随时间变化的过程进行分析,探讨人才资源国际流动的规律,并由此分析我国人才资源流动的状况。     

煤尘爆炸的影响因素与预防措施

煤尘爆炸是在高温或具有一定点火能的热源作用下,空气中氧气与煤尘急剧氧化的反应过程,是一种非常复杂的链式反应。本文主要阐述了影响煤尘爆炸的因素、预防煤尘爆炸的技术措施和限制煤尘爆炸范围的措施等问题。     

薄层罩面养护技术与施工方法

高等级公路沥青路面在交通荷载、自然气候作用下,沥青材料不断老化,路面服务水平不断下降。而薄层罩面是有效预防性养护手段之一。对常用的几类薄层罩面养护技术进行分类介绍,分析阐述了几类薄层罩面的应用。     

Electromechanical transients in liquid metal on field disruption

The present paper deals with the transient electromechanical interaction in a thin layer of liquid metal on sudden disruption of an imposed magnetic field. The problem is of fundamental importance for understanding the transient performance of various magnetohydrodynamic devices, such as electromagnetic agitators, pumps, liquid metal machines, etc.     

High yield fabrication of multilayer polydimethylsiloxane devices with freestanding micropillar arrays

A versatile method to fabricate a multilayer polydimethylsiloxane (PDMS) device with micropillar arrays within the inner layer is reported. The method includes an inexpensive but repeatable approach for PDMS lamination at high compressive force to achieve high yield of pillar molding and transfer to a temporary carrier. The process also enables micropillar-containing thin films to be used as the inner layer of PDMS devices integrated with polymer membranes. A microfluidic cell culture device was demonstrated which included multiple vertically stacked flow channels and a pillar array serving as a cage for a collagen hydrogel. The functionality of the multilayer device was demonstrated by culturing collagen-embedded fibroblasts under interstitial flow through the three-dimensional scaffold. The fabrication methods described in this paper can find applications in a variety of devices, particularly for organ-on-chip applications.     

南海中央海盆热结构及其地球动力学意义

依据南海中央海盆大地热流观测值及地壳结构资料 ,利用地热学方法计算了海盆及周缘壳内温度和热流分布 ,并得出壳幔热结构配分比例 .计算结果表明 ,中央海盆洋壳层内垂向热流变化不大 ,但垂向温度变化较大 ,这是地幔上涌所致 .海盆内成片分布的地热区 ,则是局部地区地幔上涌 ,导致多期次、多方向海底扩张的反映 .海盆区地幔热流在地表实测大地热流中所占比例高于 80 %,地壳下部热流在地壳总热流中所占比例小于 2 0 %.由此推测 ,中央海盆洋壳层 3厚度过薄 ,可能是后期热事件减缓了上地幔的冷却过程 ,而初始地壳熔融程度较低 ,2种因素综合所致     

High-throughput sorting of drops in microfluidic chips using electric capacitance

We analyze a recently introduced approach for the sorting of aqueous drops with biological content immersed in oil, using a microfluidic chip that combines the functionality of electrowetting with the high throughput of two-phase flow microfluidics. In this electrostatic sorter, three co-planar electrodes covered by a thin dielectric layer are placed directly below the fluidic channel. Switching the potential of the central electrode creates an electrical guide that leads the drop to the desired outlet. The generated force, which deflects the drop, can be tuned via the voltage. The working principle is based on a contrast in conductivity between the drop and the continuous phase, which ensures successful operation even for drops of highly conductive biological media like phosphate buffered saline. Moreover, since the electric field does not penetrate the drop, its content is protected from electrical currents and Joule heating. A simple capacitive model allows quantitative prediction of the electrostatic forces exerted on drops. The maximum achievable sorting rate is determined by a competition between electrostatic and hydrodynamic forces. Sorting speeds up to 1200 per second are demonstrated for conductive drops of 160 pl in low viscosity oil.     

Knowledge flows in the solar photovoltaic industry: Insights from patenting by Taiwan, Korea, and China

In this paper we extend work previously undertaken in industries such as semiconductor and flat panel displays to investigate knowledge flows from advanced countries (US, Japan and Europe) to catch-up follower countries (Taiwan, Korea and China), this time in the emergent solar photovoltaic industry. The solar photovoltaic industry is of particular interest in that it is poised between exploitation of first generation (crystalline silicon technologies) and new thin film and organic compound technologies, thus providing distinct sources of knowledge flow as measured by patent citations and linkage. For this study, we deploy a new database of 19,105 solar photovoltaic patents taken out by Taiwan, Korea and China at the USPTO over the 24 years 1984-2008, and analyse the knowledge flows revealed in these patents using a set of 12 International Patent Classification technology categories that we constructed. We demonstrate commonalities in patterns of knowledge flow between solar photovoltaic and earlier industries, but also suggestive differences, such as rising dependence of the catch-up countries on their own intra-national knowledge generation and flow, indicating their shift from imitation to innovation.     

不良导体热导率的阶跃函数式加热法测量研究

在获得有限平析以阶跃函数式加热瞬态温度分布近似解的基础上,设计了一个不良导体热导率阶跃函数式加热动态测量装置。该装置简单,实用,测量结果精确,有一定的实际应用价值。     

植物组织中糖化合物测定方法的研究进展

糖是植物生命现象中重要的生物高分子化合物。本文研究了近十年植物组织中糖类化合物的测定方法,为植物组织中的糖化合物的测定提供理论依据。     

Convenient surface functionalization of whole-Teflon chips with polydopamine coating

This paper presents a convenient strategy to modify the surface of whole-Teflon microfluidic chips by coating the channel walls with a thin layer of polydopamine (PDA) film, which is formed by oxidation-induced self-polymerization of dopamine in alkaline solution. Two coating strategies, static incubation and dynamic flow, are demonstrated and used for tuning the physical and chemical properties of the coated channel walls. The functionalized surfaces were investigated with the contact angle, X-ray photoelectron spectroscopy, and atomic force microscopy measurements. The coating time was optimized according to the fluorescent intensity of the green fluorescent protein immobilized on the modified surface. Applications of the PDA-modified Teflon microchips in bioanalysis were demonstrated with a typical sandwich immunoassay. Moreover, long-term cell culture experiments on modified and native Teflon chips revealed that the chip biocompatibility can be greatly improved with PDA coating. The results indicate that the surface properties of the Teflon can be easily controlled by the PDA modification, thus greatly expanding the application scope of whole-Teflon chips for various chemical and biological research fields.     

企业核心竞争力的结构解析

企业核心竞争力是由企业文化力、学习力、创新力三者有机结合形成的竞争优势的能量源。由于其内部三力的层级结构之闻的有机作用,使得企业核心竞争力得以动态发展,为企业提供了持续的竞争优势。核心竞争力整体的层级结构以及每层的核化结构对于企业评价和培育核心竞争力有着重要的价值。     

农村公路薄层水泥混凝土路面合理结构组合研究

文章总结农村公路薄层水泥混凝土路面的特点,提出该路面的合理结构组合,缓解了当前农村公路建设资金缺乏与建设规模较大的矛盾,为农村公路低造价的典型水泥混凝土路面研究提供技术支持。