用DSC研究二元体系硝酸钠——亚硝酸钠的相图

<正> 文献曾报导了硝酸钠——硝酸钾,硝酸钠——硝酸钙等二元体系的相图,但对硝酸钠——亚硝酸納二元体系的相图没有报导。本文用差示扫描量热法(DSC)研究了硝酸钠——亚硝酸钠二元体系的相图,发现其低共熔混合物在223℃时发生同分共熔,其熔化热为182J·g~(-1)。从相变温度和贮热容量考查,该低共熔混合物可以作为工业余热回收及太阳能潜热贮能的材料。     

三水合醋酸钠—乙酰胺低共熔混合物潜热贮能的研究

本文用差示扫描量热法(DSC)研究了CH_3 COONa·3H_2O—CH_3 CONH_2拟二元系统,发现其低共熔混合物在28℃时发生同分共熔,其熔化热为231J/g。从相变温度和贮热容量考查,该低共熔混合物是一种良好的太阳能潜热贮能材料。     

三水合醋酸钠——酒石酸低共熔混合物潜热贮能的研究

本文用差示扫描量热法(DSC)研究了CH_3COONa·3H_2O—C_4H_6O_6拟二元系统,发现其低共熔混合物在50℃时发生同分共熔,其熔化热为209.3J/g。从相变温度和贮热容量考查,该低共容混合物是一种良好的太阳能潜热贮能材料。     

贮热材料四氯合金属酸(Ⅱ)二烷基铵固-固相变动力学

热致相变贮热材料四卤合金属酸(Ⅱ)二烷基铵具有层状钙钛矿结构,通过晶型有序-无序转变能可逆地固-固相变贮热. 合成了两种材料四氯合锰酸十二铵n-(C12H25NH3)2MnCl4和四氯合锰酸十四铵n-(C14H29NH3)2MnCl4,并在两种材料的乙醇溶液中结晶出一系列二元混合体系. 对纯组分及各个二元体系利用差示扫描量热(DSC)测定了热分析曲线,采用Kissinger和Ozawa两种动力学模型研究了材料的非等温固-固相变动力学,计算了固-固相变过程的活化能和反应级数. 两种方法的计算结果相一致. 随着C12Mn质量分数的增加,二元体系表观活化能Ea值呈波动变化. CnMn及二元体系的反应级数均接近于1.     

长链脂肪酸体系固—液相变动力学参数的求解

用Kinssinger和Ozawa法处理长链脂肪酸体系固－液相变的DSC数据,估算出其相变反应的动力学参数,两种动力学计算结果均显示,长链脂肪酸固－液相变的表观活化能与（平均）分子量有关。     

聚乙二醇/二醋酸纤维素相变材料非等温固-固相变动力学

通过溶液共混的方法制得聚乙二醇(PEG)/二醋酸纤维素(CDA)的相变材料具有固-固相转变性质.分别对聚乙二醇及4种相变材料进行不同速率下的非等温DSC测试.采用Kissinger和Ozawa两种动力学模型研究了非等温固-固相变动力学.计算了固-固相变过程的活化能和反应级数.结果表明,两种方法求得的表观活化能Ea值一致.     

基于低共熔相变材料二元液-固相图的绘制实验设计

以有机相变材料癸酸-十二醇作为二元液-固体系相图绘制实验的研究对象,通过理论计算体系中各物质的相变温度绘制理论温度-组成(T-x)相图,并得到低共熔混合物温度和组成的理论值.配制不同摩尔分数的癸酸-十二醇混合物,利用热分析方法采用凝固点降低测定物质摩尔质量实验简单装置,测量各混合物冷却过程中相变温度,绘制有机酸-有机醇二元体系相图,得到低共熔点温度和组成,并与理论值进行比较.该实验避免了经典物理化学实验"二组分金属相图的绘制"在教学中金属样品融化温度高且耗时较长等问题,改用熔点较低的相变材料绘制固液相图,在满足二组分液-固相图实验要求的同时,将绿色化学实验设计理念融入到基础物理化学实验教学中.     

相变膨胀珍珠岩制备工艺及相变控温砂浆性能

根据低共熔相变点理论计算结果,制备月桂酸-肉豆蔻酸二元低共熔脂肪酸相变材料,以膨胀珍珠岩为无机载体,采用高温真空浸渍法制备相变骨料,并对其进行包裹,确定最佳包裹材料及掺量.通过场发射扫描电镜观测相变骨料切割截面,脂肪酸经吸附进入多孔颗粒内部,并黏附于珍珠岩孔隙内壁,经石蜡包裹后脂肪酸相变材料较稳定地处于石蜡与膨胀珍珠岩内壁包围的孔空间内.利用相变骨料制备相变控温砂浆,测试其物理力学性能及热性能.结果表明:相变珍珠岩砂浆板物理力学性能达到建筑保温砂浆标准要求,且具有较好的控温效果,随着脂肪酸掺量的增加,有效热量值降低越多,温度延时越长,降温幅度越大.     

长链脂肪酸系列固-液相变动力学的研究

长链脂肪酸可作为有机固 -液相变贮热材料 .利用 Kissinger及 Ozawa两种非等温动力学模型 ,处理了几种具有偶数碳原子长链脂肪酸的 DSC实测曲线 ,计算了固 -液相变过程中的表观活化能和反应级数 .1　实验部分1 .1　仪器使用美国 PE公司的 DSC- 7型差示扫描量热仪 .以α- Al2 O3 作参比物 ,扫描速率分别为 3,5,7℃ /min,样品、参比物均在 2 .2 mg左右 ,采用密封铝坩锅 ,在空气气氛中进行测试 .1 .2　药品实验所用试剂为癸酸 ( CR) ,月桂酸 ( CR) ,棕榈酸 ( AR) .2　结果及处理2 .1　实验结果对试样癸酸、月桂酸、棕榈酸分别测得 φ=3…     

适用与蓄冷空调的二元相变蓄冷材料的测试与研究

研究了空调蓄冷技术对蓄冷相变材料各种性质的要求,提出了一种新型的二元相变低共熔蓄冷介质并进行了性能测试,该介质的凝固温度为4.8～5.3℃,固—液相变潜热为149kJ?kg,主要成分为辛酸和月桂酸构成的低共熔混合物,其特点是材料有良好的可重复使用性,潜热和显热蓄冷量大,是一种有发展前途的蓄冷介质。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that