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1.
运用热重分析和傅里叶变换红外光谱分析技术,对夏夷扇贝棱柱层和珍珠层粉末样品进行温度变化性质研究.研究结果表明,贝壳棱柱层和珍珠层的主要成分均为方解石型碳酸钙,并含有少量有机质和水分,棱柱层有机质含量高于珍珠层.珍珠层和棱柱层样品分别于600℃、700℃发生碳化,所含有机物分别于700℃、800℃发生完全分解,同时热处理前后红外光谱吸收峰的峰形、峰位发生了明显变化,有机质含量的高低与CO32-不对称伸缩振动ν3的峰位负相关,而与CO32-的面内弯曲振动2ν、面外弯曲振动ν4无关.变化表明,热分解前存在生物大分子与方解石型碳酸钙的配位作用,从分子结构水平上揭示了生物矿化材料中有机质对无机晶体的配位作用.  相似文献   

2.
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...  相似文献   

3.
褶纹冠蚌贝壳结构特征及其珍珠层呈色机制研究   总被引:1,自引:0,他引:1  
采用反射光谱仪和扫描电镜(SEM)对淡水褶纹冠蚌贝壳壳层微结构及珍珠层彩虹色成因进行较系统研究,对珍珠层构色机制进行了理论模拟。结果表明:贝壳棱柱层为棒柱结构,且与珍珠层呈近垂直交接;同一贝壳的珍珠层,生长端存在明显的彩虹色,且反射波长位于蓝绿波段,而成熟端无明显颜色和反射波长;构成珍珠层成熟和生长端文石板片厚度存在明显差异,且两者厚度分别约为1 483 nm和426 nm;珍珠层中文石板片与蛋白质周期排列构成一光子带隙结构,该结构与蛋白质色素的共同作用是其颜色产生的直接原因。  相似文献   

4.
通过紫外-可见(ultraviolet-visible, UV-VIS)吸收光谱、场发射扫描电镜(field emissionscanning electron microscope, FE-SEM)与傅里叶变换红外(Fourier transform infrared,FTIR)光谱对海水养殖金色珍珠(golden seawater cultured pearl, gold CP)的微结构及其吸收光谱特征进行了较系统的研究. 结果表明: 海水养殖金色珍珠外表面珍珠层“叠瓦状”结构的疏密程度在其表面的不同区域存在不同, 该特征可能是导致金色珍珠不同区域的紫外-可见吸收光谱存在差异的因素之一; 在由内向外的方向上, 接近珍珠核心处的珍珠层中未见单一的文石板片或棱柱结构, 而在珍珠层的中部及外侧区域均为文石板片结构; 珍珠层的外表面由多级结构构成, 其中单个珍珠层微米级的文石板片由纳米级文石小颗粒组成.  相似文献   

5.
甲胺分子240 nm Nn→3s弱激发光谱分析   总被引:1,自引:0,他引:1  
利用共振增强多光子电离(REMPI)方法,在233-243 nm激光波长范围内,研究了甲胺分子的REMPI光谱,标识了在此波段激光作用下0-0跃迁带头,频率为41699 cm-1,以及9ν振动模式,频率为634cm-1.用密度泛函理论(DFT)B3LYP方法、从头算HF和微扰理论MP2方法在6-31*基组水平上对甲胺分子处于基态和激发态时的振动光谱进行了理论研究,得到其激发态9ν振动模式为648 cm-1.理论计算的结果与实验值相差为14 cm-1,二者基本上一致.  相似文献   

6.
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.  相似文献   

7.
线性分子C3的解析势能函数   总被引:1,自引:1,他引:0  
应用群论及原子分子反应静力学方法推导C3分子的电子态及其离解极限,在B3P86/CC-PVTZ水平上,对C3分子基态进行优化计算,得出基态C3的单重态能量最低,其稳定构型为的D∞h构型,平衡核间距Re=0.1288 nm、能量为-114.3852 a.u..同时计算出基态的简正振动频率:对称伸缩振动频率ν(Π)=69.4978 cm-1,弯曲振动频率ν(∑g)=1242.4749 cm-1和反对称伸缩振动频率ν(∑u)=2153.1569 cm-1.在此基础上,使用多体项展式理论方法,导出了基态C3分子的全空间解析势能函数,该势能函数准确再现了C3 (D∞h)平衡结构.  相似文献   

8.
应用群论及原子分子反应静力学方法推导了OCS分子的电子态及其离解极限,采用B3P86方法,在CC-PVTZ水平上,优化出OCS基态分子稳定构型为三重态的Cs构型,其平衡核间距RC-S=0.1768 nm、RC-O=0.1179 nm、∠OCS=122.9°,能量为-512.0405a.u..同时计算出基态的简正振动频率:对称伸缩振动频率ν(A')=354.5cm-1,弯曲振动频率ν(A')=633.5 cm-1和反对称伸缩振动频率ν(A')=1792.8 cm-1.在此基础上,使用多体项展式理论方法,导出了基态OCS分子的全空间解析势能函数,该势能函数准确再现了OCS(Cs)平衡结构.  相似文献   

9.
应用群论及原子分子反应静力学方法推导了OCS分子的电子态及其离解极限,采用B3P86方法,在CC-PVTZ水平上,优化出OCS基态分子稳定构型为三重态的Cs构型,其平衡核间距RC-S=0.1768nm、RC-O=0.1179nm、∠OCS=122.9,°能量为-512.0405 a.u.。同时计算出基态的简正振动频率:对称伸缩振动频率ν(A′)=354.5cm-1,弯曲振动频率ν(A′)=633.5cm-1和反对称伸缩振动频率ν(A′)=1792.8cm-1。在此基础上,使用多体项展式理论方法,导出了基态OCS分子的全空间解析势能函数,该势能函数准确再现了OCS(Cs)平衡结构。  相似文献   

10.
珍珠层的FTRaman光谱特征   总被引:1,自引:0,他引:1  
采用傅里叶变换拉曼光谱(FT-Raman)对我国三角帆蚌贝壳珍珠层及其在150℃处理1至15h不等后的样品进行了研究,并与相应的激光拉曼光谱进行了对比,结果表明,两类拉曼光谱均能观察到珍珠层中无机相文石的特征拉曼峰,但各身的相对强度稍有不同,FT-Raman光谱中可观察到两个有机质的拉曼峰,位置为1507cm^-1和1127cm^-1,它们在加热6h后消失,这与激光拉曼光谱可观察到类胡萝卜素的拉曼峰明显不同,此外,FT-Raman研究证实在150℃加热即使长达15h,珍珠层中的文石依然未发生相变。  相似文献   

11.
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.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

13.
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。  相似文献   

14.
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.  相似文献   

15.
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-  相似文献   

16.
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-  相似文献   

17.
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  相似文献   

18.
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  相似文献   

19.
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  相似文献   

20.
<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  相似文献   

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