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。     

贝壳中文石晶体择优取向的XRD分析

贝壳珍珠层独特的结构是其优异力学性能的重要原因.采用X射线衍射法(XRD)对贝壳珍珠层及柱状晶的晶体结构及择优取向进行了详细的探讨.结果表明:珍珠层中文石晶体在沿珍珠层面上存在两种定向排列,即(002)和(012),具有择优取向性,柱状晶层结构的无序性比珍珠层大.     

珍珠中碳酸钙与有机基质之间相互作用的研究

首次利用傅里叶变换红外光谱法对珍珠进行了表征,从碳酸钙红外谱带的位置及形状的变化直接证实了珍珠中亚微米级文石型碳酸钙晶体与有机基质界面之间存在着较强的络合作用。结合ICP-AES成分分析和SEM形貌分析,表明了上述络合作用正是珍珠形成高度有序的层状结构、且具有高强度、高韧性的化学本质。     

H_2O_2和NaOH溶液作用下珍珠腐蚀和结晶的研究

用扫描电镜（ＳＥＭ）观察了珍珠以及用１０％Ｈ２Ｏ２和１ｍｏｌ／ＬＮａＯＨ溶液腐蚀后珍珠样品的横断面和纵剖面形貌。１０％Ｈ２Ｏ２酸性溶液对珍珠从晶界开始并沿晶界形成腐蚀坑。在碱性溶液中,珍珠由于角质蛋白质的降解而被腐蚀,腐蚀也是沿晶界形成腐蚀坑。珍珠表面存在结晶现象,横断面上生成疏松多孔结构并在该结构上生长宝石花状、叶片状以及颗粒状晶体。纵剖面上没有疏松多孔结构。结果表明,珍珠文石晶片结构和成分不均匀性,以及蛋白质在ＣａＣＯ３形核结晶过程中起着引导作用。     

海水养殖金色珍珠独特的吸收光谱及其微结构

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.     

滑跃式甲板气流场数值模拟

利用FLUENT软件对舰船进行数值模拟,与已有风洞实验数据对比分析,验证数值模拟的准确性．针对滑跃式舰船甲板,讨论不同网格形式对计算结果的影响,发现棱柱层网格可以改善计算过程的收敛特性,提高收敛速度,沿甲板边界的网格细化是采集船首和边界涡产生的关键．通过对全尺寸的滑跃式甲板舰船船型的计算,得到船首分离涡和岛型建筑后面复杂的涡旋结构．结果表明：岛型建筑分离涡计算的准确度直接影响了岛型建筑下游流场的整体特征;船体尺寸和岛形建筑的形状和位置会严重影响船后涡旋的强度和位置．     

贝壳韧带微结构的高分辨扫描电镜研究

采用高分辨SEM及XRD对合浦珠母贝韧带进行了研究,结果表明,合浦珠母贝韧带无机相主要由文石组成.韧带具有明显的层状结构,同一生长层及相隔生长层中文石纤维呈一致定向排列,而相邻生长层文石纤维的定向明显不同,呈“交叉棱柱层”结构样式.合浦珠母贝韧带中文石纤维的直径为80~90 nm,具有典型的2D光子晶体结构特征.     

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。     

Different fossil brachiopod skeletal microstructure of different information on carbon and oxygen isotope contents

Whether there is isotope fractionation caused by metabolism (vital effect) of bra-chiopods in geologic time with their shells' δ18O and δ13C has been studied intensively in the field of carbonate isotope geochemistry in the last decade. The approach to dealing with the problem is by comparing isotopic compositions between different fossil brachiopods with their secondary shells which usually consist of two kinds of layers: prismatic layer composed of prismatic low-Mg calcite crystals, and fibrous layer comprising fibrous ones. The isotopic compositions of the two secondary layers have been investigated by comparison of carbon and oxygen isotopic compositions between five genera of Atrypidae collected from Givetian, Middle Devonian in Longmenshan, Sichuan Province, China. Due to different microstructures of the two secondary layers, their abilities to prevent from being altered by diagenesis are also different, thus in their state of preservation. The fibrous layer is more susceptible to the diagenetic alternation than the prismatic one in the way of microfracture filling between fibrous crystals in the elongated direction. Consequently, the isotopic compositions of the fibrous layer are systematically lower than those of the prismatic layer in their δ18O and δ13C by (0.53 ± 0.08)‰ and (0. 12 ± 0.04)‰, respectively. This suggests that further studies of vital effects with brachiopod in geological times by comparison of isotopic compositions in the secondary shell take into consideration of the different states of preservation between the fibrous and the prismatic layer.     

珍珠漂白

该文利用简易的实验装置, 设计了十多种漂白配方, 对合浦珍珠 （等外） 进行了漂白试验, 经过对比, 筛选出优化的配方和工艺, 利用优化的配方和工艺漂白珍珠, 漂白迅速,珍珠色泽好。在此过程中, 还找到了一种性能优良的漂白液ｐＨ 值稳定剂。     

融合梯度向量流条纹探测与图切法相位解缠

为解决GVF-Snake(gradient vector flow snake)条纹探测相位解缠时,内部条纹线探测偏离条纹边界的问题,提出了一种融合GVF-Snake条纹探测与马尔科夫随机场(Markov random field,MRF)图切法相位解缠方法.通过判断出条纹探测线不是真实条纹边界的情况,对该条纹探测线上一步探测条纹的内部块用MRF图切法进行分割解缠,按照相应解缠准则将两种解缠结果进行融合,形成含有边界跳跃点的粗解缠结果,并用高通滤波插值法消除粗解缠结果的边界孤立点的方法研究了矿区梯度较大地区的相位解缠.结果表明:以巨野矿区某工作面为实验区,用两景sentinel-1A的单视复数图像进行两轨法干涉处理的真实相位来验证算法的有效性.在面分析上,以自适应局部平滑相位评估(phase estimation using adaptive regulation based on local smoothing,PEARLS)为评价标准,将本文方法与最小费用流等5种相位解缠算法进行比较.对比结果显示,本文方法的平方根误差、平均绝对误差分别是±0.0791、±0.0090、±2.3173 rad.在线分析上,对只含有变形相位的绝对相位,提取各解缠绝对相位工作面走向线、倾向线的变形.以实际水准观测值为标准,本文方法的平方根误差、平均绝对误差、绝对值最大误差分别是±0.17748、±0.14107、±0.40529 cm.面分析中以PEARLS相位重构为基准,可见本文方法要优于其他常规的解缠方法;同理,线分析中以水准数据作为依据其各项指标亦为最优.     

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．     

Aragonite-calcite transformation in fossil snail shells of loess sequences in Loess Plateau, Central China

The methods of X-ray diffraction (XRD) and ICP-AES are applied to analyzing the mineral composition of modern and fossil snail shells in Luochuan section and Xifeng section. The results show that the mineral phase of calcium carbonate in modern snail shells is aragonite, but for some fossil snail shells in certain layers of loess sequences, a part of aragonite is transformed into calcite. In Luochuan and Xifeng sections, the stratigraphic borderline of aragonite-calcite transformation appearing obviously is between L5 and L6. Under the earth surface condition, the aragonite-calcite transformation is influenced by the factor of temperature only in a long time scale. It seems that the pressure is not the factor influencing the aragonite-calcite transformation. The results also show that existing age of snail shells is possibly the dominant and principal factor for the aragonlte-calcite transformation. To a certain extent, thed egree of aragonite-calcite transformation in snail shell is controlled by the content of trace element, such as Mg^2 . The trace element can improve the stability of snail shell aragonlte and impede the process of aragonite transforming into calcite.     

合浦珍珠的宝石学特征及珍珠优化处理研究

研究了化学优化处理前后合浦珍珠的宝石学特征及影响珍珠质量的因素．提出了珍珠具多元构造的特征．珍珠久置变黄及优化后珍珠返黄是由于珍珠中有机物质和变价微量元素等受侵蚀氧化分解所致．     

乌龟卵壳结构的研究

本文对乌龟卵壳在扫描电镜下的微观结构进行了研究.乌龟卵壳主要由钙质层与壳膜组成.钙质层由霰石状态的碳酸钙晶体组成,可分为许多个壳单位,每个壳单位由同一中心辐射出来的针状晶体构成.卵壳的外表面具有一定的饰纹,有些部位还分布有纵横交错的有机纤维和块状的有机物质.壳膜由多层网状纤维组成,没有内、外壳膜之分.龟卵在孵化过程中不形成气室.同时对孵化前后龟卵壳的结构进行了对比研究.     

Dynamic analysis of preferential orientation of aragonite crystals in nacre from mollusk shell

Based on the scanning electron microscope (SEM) observations, it is confirmed that the nacre is composed of aragonite crystals and organic matrix with interlaced arrangement, showing ordered "brick-mortar" structure. The dynamic analysis of preferential orientation of aragonite crystals in the nacre from the abalone (Haliotis diverscolor supertexta) with different shell ages is systematically investigated using X-ray diffraction (XRD) and high resolution transmission electron microscope (HRTEM). Experiments reveal that, in the nacre from the juvenile mollusk shell, there exist three kinds of orientations of aragonite crystals: (113), (002) and (012). However, along with the growing of the mollusk shell, the intensity of (012) and (113) becomes weak, and the (002) becomes the preferred crystal orientation of aragonite in the nacre from the adult mollusk shell, which means that the c axis of aragonite crystals is perpendicular to the nacreous layers. The results obtained show that the nacre possesses a highly ordered structure at the micrometer/nanometer multiscale levels.     

基于 Swin Transformer 和 Style-based Generator 的盲人脸修复

盲人脸修复任务是从低质量的图像（例如模糊、噪声和压缩图像）中恢复高质量的图像.由于事先不知道低质量图像的退化类型和退化参数,因此盲人脸修复是一个高度病态的问题,在修复过程中严重依赖各种先验指导.然而,由于面部成分和面部标志等面部先验通常是从低质量图像中提取或估计的,可能存在不准确的情况,这直接影响最终的修复性能,因此难以有效利用这些先验知识.此外,目前的主流方法基本都是依赖ConvNets进行特征提取,没有很好地考虑长距离特征,导致最终结果缺乏连续一致性.本文提出了一种改进的StyleGAN模型,命名为SwinStyleGAN,应用在高级视觉任务上表现出色的Swin Transformer来提取长距离特征,并通过改进后的类StyleGAN合成网络逐步生成图像.本文设计了一个空间注意力转换模块SAT来重新分配每个阶段特征的像素权重,以进一步约束生成器.大量实验表明,本文提出的方法具有更好的盲人脸修复性能.     

电位对无捕收剂溶液中黄铜矿表面化学构成的影响

采用循环伏安法、X射线光电子能谱研究了黄铜矿在中性无捕收剂浮选介质中不同电位极化后其表面产物相的化学构成.结果显示黄铜矿在中性无捕收剂溶液中表面相中的S以具有黄铜矿晶体结构的亚稳相缺金属硫化物CuFe1-xS2,CuS2和稳定相多硫化物Sn-的形态存在.当电位提高到0.1 V/SCE,表面相中的Sn-消失,大量的S0和少量高价态(+4/+6)硫相(S2O23-/SO24-)形成.当极化电位大于0.35 V/SCE,表面相中S0的量急剧减小,氧化形成了大量的高价态(+4/+6)硫相(S2O23-/SO24-).表面相中的Cu以CuFe1-xS2的形式存在,高电位下出现少量的CuO相.Fe在低电位...     

能量法求解全柔性微动机器人移动副的刚度

全柔性机构中柔性移动副(P副)刚度的求解是进行全柔性并联机构、全柔性并联微动机器人分析的基础工作之一．在柔性铰链力学模型的基础上,利用能量法得出了非对称3．RRRP(4R)全柔性并联机构的变截面柔性移动副(4R)单元上所受外力与端部变形之间的关系,结合柔性铰链的柔性刚度矩阵求得柔性移动副单元刚度表达式方程．并用ANSYS工程软件建立相同的柔性移动副模型进行模拟,模拟结果表明,推导的柔性移动副的刚度与模拟结果很相近,刚度的理论方程具有一定的准确性。     

Morphology and Polymorph Control of Calcium Carbonate via a Facile Additive-Free Route

In this paper, we reported a facile additive-free route for synthesizing calcium carbonate(CaCO_3) with different morphologies and polymorphs by a precipitation reaction method between Ca(CH_3COO)_2 and NaHCO_3 in water and ethylene glycol(H_2O/EG) mixed solvent. It has been found that the concentration of Ca~(2+) and HCO_3~-, the volume ratio of H_2O/EG and the reaction temperature are turned out to be important parameters for the morphology and polymorph of Ca CO_3. Various interesting morphologies, such as the spherical, elliptoid, spindle-like, petal-like, cricoid, cubic, plate-like and rod-like can be easily obtained. Pure polymorphs of vaterite, calcite and aragonite can also be tuned by adjusting experimental conditions. The studies might be helpful to provide new insights into the morphosynthesis and crystalline phase control of other inorganic materials.O 611.4; O 643.1