共查询到20条相似文献，搜索用时 46 毫秒
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用合成的水合四硼酸钾和偏硼酸钾晶体,配制一系列溶液,研究了pH与浓度变化的关系,并计算硼酸根离子的摩尔分数-浓度(δ-c)关系图。用拉曼光谱方法研究四硼酸钾和偏硼酸钾溶液,给出其拉曼光谱图,并对各峰进行了归属。研究表明,四硼酸钾溶液中存在的物种主要有[B4O5(OH)4]2-、[B3O3(OH)4]-和[B(OH)4]-,而其它物种所占摩尔分数很小;在偏硼酸钾水溶液中,[B(OH)4]-占绝大多数,有很少量H3BO3、[B4O5(OH)4]2-和[B3O3(OH)4]3-。硼酸盐离子浓度越低,越容易水解为聚合度较低的简单物种。 相似文献
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由摩尔比为1∶2的Cs2CO3和H3BO3反应得到四硼酸铯样品,用FT-IR和Raman等方法对其溶液结构进行表征并分析其中的阴离子类型。同时测定了四硼酸铯溶液在298.15 K和333.15 K下的密度、电导及p H,通过298.15 K下的pH测量值和相关硼酸盐平衡常数,计算298.15 K下四硼酸铯溶液的化学物种分布,并对其相互转换反应进行推测。研究表明,298.15 K下四硼酸铯溶液中存在的主要物种有B(OH)4-、B(OH)3、B3O3(OH)4-、B3O3(OH)52-和B4O5(OH)42-,与Raman光谱所得结果基本一致。 相似文献
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用等压法研究了LiCl-Li2 B4O7-H2 O体系离子强度范围为 0 1 5 3 0～ 3 0 75 8mol kg-1不同质量摩尔浓度分数的等压平衡浓度 ,水活度 ;计算了LiCl和Li2 B4O7,混合盐溶液的饱和蒸汽压 ,渗透系数等热力学性质。以总硼浓度 0 0 8mol·kg-1为界 ,把所有混合盐的实验数据分为高浓度和低浓度两部分 ,按照不同的物种生成转化反应 ,考虑溶液中H3 BO3 和硼氧配阴离子B(OH) 4 -,B3 O3 (OH) 4 -和B4O5(OH) 4 2 -的存在形式。由实验数据用最小二乘法和迭代法求取了LiB(OH) 4 离子对的缔合平衡常数Km1,B3 O3 ,(OH) 4 离子的生成转化反应的化学计量平衡常数Km2 ,以及Pitzer模型的离子相互作用参数。用该模型计算的渗透系数值与实验结果取得合理的一致。对完善含锂、硼盐湖卤水体系的热力学模型和盐湖资源的综合开发具有重要意义 相似文献
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利用牛顿迭代方法计算给出硼酸钾溶液中硼酸根离子的物种分布图。研究给出溶液中硼酸根离子的类型、含量以及各硼酸根离子间相互转化方程式,并简单谈论了温度和浓度对硼酸根离子类型和含量的影响。在五硼酸钾溶液中主要硼酸根离子物种为B3O3(OH)4-,B4O5(OH)42-和B(OH)3,而B5O6(OH)4-含量非常低,可以忽略不计;偏硼酸钾溶液中主要离子为B(OH)4-;在高浓四硼酸钾溶液中主要物种为B3O3(OH)4-,B4O5(OH)42-和B(OH)4-。最后用Otakar和Casteel-Amis经验方程式分别研究了硼酸钾溶液的密度和电导率。 相似文献
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《湿地科学与管理》2017,(1)
<正>环境是最稀缺的资源生态是最宝贵的财富资质平台:南京大学常熟生态研究院成立于2012年,是一个集环保、林业、湿地、旅游等各种规划资质和技术的推广平台,并通过了ISO9001国际质量管理体系及高新企业认证。研究院提供生态环境咨询、规划、设计、监测、科普、管护、建设服务项目:等技术服务。开展的服务已遍布全国,横跨全国10个省和自治区,37个市县,约占我国湿地总面积的5.0‰。核心技术:研究院具有技术发明专利三十余项,其中国际专利两项;分为生态修复、辅助设备研发、湿地强化净化、植物规模化培育技术四大类别。创建了"强化-耦联-侧渗-削减的河流梯级净化工艺"、"沉淀-曝气-表流-潜流-稳定塘尾水强化处理 相似文献
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The first issue of ANTARCTIC RESEARCH comes into the world.I greatly rcjoice andwarmly.congratulate on its start publication.Chinese Antarctic research started in a late time,but gets a rapid development.Especially inrecent years,a Chinese Antarctic investigation station named Great Wall Station was established,three extensive multidisciplinary investigations were carried out in.the area of the station,and thegratifying results of the preliminary study were obtained.So the Chinese scientists have the abilityto undertake independent investigations on Antarctica and gained some experience in the research.This success has 相似文献
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Elvin Wyly 《Urban geography》2013,34(5):669-690
With a mantra that ‘nobody is as smart as everybody,’ Google maintains giant databases that enable unprecedented quantitative analysis of a social world that is now majority urban. A Wall Street web-based broker offers an App that promises to turn ‘thoughts into trades.’ Economists and marketers now use evolutionary theory in ‘neuroimaging’ brain scans of consumer behavior. The United States Air Force now trains more joystick-maestro drone pilots than old-fashioned Do-the-Right-Stuff human fighters and bombers. In this article, I suggest that these trends signal a troubling reincarnation of an aggressive Right-wing (post)positivist zombie reanimated by global, digitized neoliberalism. The long-forgotten revolutionary project launched by Auguste Comte in 1822 was hijacked and corrupted after his death, and now we confront a hybrid cyborg zombie, a dehumanized, automated adaptation to the post-structuralist situated knowledges of consumer sovereignty. #Comtebot: The positivist era is right now; the question is what kinds of politics it will have. 相似文献
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Summary. We reduce the problem of constructing a smooth, 1-D, monotoni-cally increasing velocity profile consistent with discrete, inexact τ ( p ) and X( p ) data to a quadratic programming problem with linear inequality constraints. For a finite-dimensional realization of the problem it is possible to find a smooth velocity profile consistent with the data whenever such a profile exists. We introduce an unusual functional measure of roughness equivalent to the second central moment or 'Variance' of the derivative of depth with respect to velocity for smooth profiles, and we prove that its minimal value is unique. In our experience, solutions minimizing this functional are very smooth in the sense of the two-norm of the second derivative and can be constructed inexpensively by solving one quadratic programming problem. Still smoother models (in more traditional measures) may be generated iteratively with additional quadratic programs. All the resulting models satisfy the τ ( p ) and X( p ) data and reproduce travel-time data remarkably well, although sometimes τ ( p ) data alone are insufficient to ensure arrivals at large X; then an X( p ) datum must be included. 相似文献
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DAVID SIMON 《The Geographical journal》2006,172(1):10-21
The relationship between mainstream development policy (and perhaps also development studies) and postcolonial theorists has often been characterized as a dialogue of the deaf. Rather like in the old 'debates' between adherents of modernization and neo-Marxist theories, the protagonists are often thought to be talking at or past one another, rather than with each other. This paper reassesses some firmly held views on both sides of the schism. On the one hand, many official development agencies appear to promote business as usual (often quite literally, as a recent War on Want report attests in the case of the UK's DFID using its aid budget to promote profitable opportunities for British corporations). On the other hand, some postcolonial purists rely on surprisingly modernist, totalizing discursive techniques while claiming post-structural credentials, or baulk at the prospects of practical engagement. Discrepancies between theory, discourse, policy and practice are not the preserve of one side. However, the middle ground is firmer and better trodden than most believe. Considerable progress has been made and the paper assesses examples of productive engagement and concludes with suggestions for carrying forward the challenges. 相似文献
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