珍珠组成与结构的研究

利用现代测试技术对人工淡水养殖珍珠进行了红外光谱、X射线衍射、光学显微镜和扫描电子显微分析,以了解珍珠的化学组成和矿物组成及其内部晶粒形貌、晶粒尺寸和排列方式对珍珠光泽的影响,同时还在扫描电子显微镜下观察了珍珠的表面形貌特征。     

马氏珠母贝天然珍珠的结构分析

应用光学显微镜和扫描电子显微镜对30颗直径约为2 mm的马氏珠母贝天然海水珍珠进行了显微结构和超微结构的观察,结果表明:在马氏珠母贝天然珍珠的中心区域无不定型基质,也无棱柱层,其完全是由文石单晶层构成;珍珠的珍珠层内部结构与人工养殖珍珠相似,珍珠层存在断层现象;靠近珍珠表面的文石晶片层厚度为(0.24±0.03)μm,呈"砌墙式"排列,排列非常整齐、均匀致密,并与珍珠表面平行;珍珠内部的文石晶片层的厚度为(0.28±0.03)μm;珍珠表面的晶层融合状态良好,单晶体的顶面观呈近正六边形,彼此间结合紧密且光滑.     

广西合浦养殖珍珠的宝石学特征

合浦养殖珍珠的结构可分为珍珠层型、棱柱层型及复合型三类。化学成分主要为碳酸钙，其次为有机质和水，此外含有多种微量元素。矿物成分是由碳酸钙的两种矿物相－文石和方解石组成，文石为主要组成矿物，文石与方解石含量的比值愈高，珍珠质量愈好，反之，愈差。珍珠中的微量元素没有以类质同像方式参与到矿物晶格中，水是以吸附态存在。珍珠的颜色以白色、淡黄色为主，密度２．６５～２．７６ｇ／ｃｍ３，维氏硬度１６３～１８３ｋｇ／ｍｍ２，折光率１．５３３～１．６９０，珍珠形态以圆形为主，大小一般在４～７ｍｍ，珍珠工艺性能的评价通常采用“光、重、圆、大”四字标准。     

硅凝胶体系中碳酸钙晶体生长实验

为了得到不同晶型的碳酸钙晶体,采用凝胶法生长出了碳酸钙的三种同质异象体：方解石、文石、球霰石．讨论了反应物浓度和杂质离子（Na^＋）对碳酸钙晶体生长的影响．结果表明：通过改变反应物浓度和利用不同的反应物可以生长出不同晶型的碳酸钙晶体．同时,利用原子力显微镜对生长的方解石晶体表面的形貌观察发现：晶体生长是以台阶簇（大台阶）的方式推进,不同高度的堆垛层错呈现在表面上．     

翡翠贻贝贝壳的微结构研究

双壳纲贝壳是一种天然的有机一无机复合材料,具有优异的力学性能.为了解翡翠贻贝贝壳的矿物组成和微结构,利用X射线衍射仪(XRD)对贝壳进行分析,并利用扫描电镜(SEM)对其生长区和成熟区珍珠层微结构进行观察.结果表明,该贝壳珍珠层、棱柱层及其过渡区域均由文石组成;首次发现该贝壳珍珠层由帽状和平板状文石板片构成,其弯曲度和...     

碱环境下单碳型水化碳铝酸钙加速碳酸化机理

单碳型水化碳铝酸钙是钢渣水化后的矿物之一．通过X射线衍射、热重分析、傅里叶红外光谱以及场发射扫描电镜对单碳型水化碳铝酸钙在碱环境下加速碳酸化的矿物衍变进行了分析．结果表明,不同碱浓度下单碳型水化碳铝酸钙加速碳酸化的主要产物为方解石、文石、球霰石和无定形的含铝矿物．随着碱浓度的增加,方解石析晶先受到促进后被抑制;文石析晶先被抑制后受到促进;球霰石析晶则一直被抑制且形成的晶体结构不稳定．在碱浓度为1 mol/L,即pH为14时,单碳型水化碳铝酸钙经碳酸化处理几乎不生成文石,而在碱浓度为0.01 mol/L,即pH为12时,单碳型水化碳铝酸钙碳酸化反应后生成针棒状文石晶体．     

阻垢剂HEDP和PBTCA阻垢机理探讨

碳酸钙晶体有3种晶相方解石、球霰石、文石.阻垢剂HEDP(羟基乙叉二膦酸)和PBTCA(2膦酸基丁烷1,2,4三羧酸)对碳酸钙晶体不同晶相的作用效果不同.实验结果表明,HEDP对方解石有很好的抑制作用,而对球霰石和文石则没有明显抑制效果.PBTCA对方解石和球霰石都有很好的抑制作用,对文石作用效果不明显.基于量子化学半经验方法,计算了HEDP和PBTCA的几何构型和分子中各原子所带电荷;由几何匹配理论说明HEDP可以抑制方解石的生长;PBTCA既能抑制方解石的生长,也能抑制球霰石的生长.     

尼龙6/聚对苯甲酰胺共混物的形态

研究了文题共混物的结晶形态与热行为。发现该共混物的硫酸溶液可呈现液晶态。无论是液晶态,还是非液晶态,聚对苯甲酰胺都可以诱发尼龙与其共晶。由非液晶态得到的球晶,在偏光显微镜下可观察到黑十字消光图象,而由液晶态得到的球晶没有明显的黑十字消光图象。由液晶态析出的共混物容易结晶,并且熔点要高于由非液晶态析出的共混物。扫描电镜观察表明共混物球晶具有均相结构。X-衍射分析证明了尼龙6与聚对苯甲酰胺这两种聚合物具有相近的晶格结构,分子链节可以在晶格中互相取代。生成共晶。     

鳜鱼耳石中物相组成的研究

生物成因的碳酸钙在自然界普遍存在。已有研究表明,鳜鱼耳石的主要无机矿物组成是碳酸钙,研究鳜鱼耳石中的碳酸钙物相组成有助于推理这些生物成因碳酸钙的矿化过程,为合成具有特定结构和功能的钙盐类材料提供有益的思考和实践途径。本文从鳜鱼中提取微耳石进行红外光谱和 XRD 分析,结果表明鳜鱼的微耳石为文石矿物相,扫描电镜观察发现其有着片层状的纤维结构。     

河蚌壳的微结构及红外光谱分析

对河蚌壳珍珠层进行TEM观察,发现有机质中矿物桥的存在,在珍珠层片层中还初次发现了大量层错,其呈随机分布.对珍珠层及棱柱层进行红外光谱分析,结果表明:棱柱层二重简并的反对称伸缩振动ν3的频率与天然无机文石相比存在蓝移,蓝移值为9.29 cm-1,珍珠层文石不存在蓝移现象;珍珠层与棱柱层的面外弯曲振动ν2的频率与天然无机文石相比都存在明显的蓝移现象,蓝移值分别为6.83 cm-1和2.9cm-1.     

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.     

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.     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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