共查询到20条相似文献,搜索用时 187 毫秒
1.
2.
3.
4.
5.
6.
针对KDP晶体生长过程中常出现的SO2-4,NO-3和Cl-杂质,采用传统法和快速法掺杂生长了一系列KDP晶体,研究了不同阴离子杂质掺杂对KDP晶体X和Z向的电导率的影响.结果表明,X向的电导率比Z向电导率高;未掺杂时,快速生长的KDP晶体比传统法生长的KDP晶体具有更高的电导率; SO2-4的掺杂增大了晶体在两个方向的电导率,且随着掺杂浓度的增加,晶体的电导率也相应增大;NO-3和Cl-对KDP晶体的电导率影响不大.分析认为,快速生长的KDP晶体具有更高的缺陷浓度,从而增大了晶体的电导率;SO2-4具有与PO3-4结构的相似性,从而能够取代部分PO3-4进入晶格,从而产生H+空位.H+空位的定向移动能增大晶体的电导率.而NO-3和Cl-与PO3-4结构差异较大,很难取代进入PO3-4晶格,因此NO-3和Cl-对KDP晶体的电导率影响不大. 相似文献
7.
脂质体中生物矿化的研究进展 总被引:1,自引:2,他引:1
生物矿化是指在有机体内形成矿物的过程。以脂质体作为模板,不仅可以模拟生物矿化过程中有机基质的调控作用和生物大分子的指导作用,而且可以提供生物矿化所需的特殊隔室,使反应物富集、定位,催化矿化反应的发生。本文综述了近年来在脂质体中模拟生物矿物磷酸钙、碳酸钙和草酸钙等矿化的研究进展,并讨论了膜控制晶体生长的机理。 相似文献
8.
采用提拉法成功生长了氮化镓和氧化锌基外延薄膜晶格匹配的ScAlMgO4单晶衬底材料,晶体呈透明白色,尺寸为30mm×59mm,表面部分沿解理面有裂纹.粉末X射线衍射(XRD)分析表明经1400℃固相反应烧结的原料基本合成了ScAlMgO4多晶相.初步的偏光显微镜观察、晶体的粉末XRD表征、透过光谱和双晶摇摆测试表明晶体具有较好的光学性质和结晶质量.研究表明晶体本身的层状结构、较大的温度梯度和热应力的不均匀性是生长过程中引起晶体开裂的几个主要原因. 相似文献
9.
10.
基于AlInGaAsP材料的应变平衡量子阱太阳能电池 总被引:2,自引:0,他引:2
近年来,基于晶格匹配的多结太阳能电池光电转换效率已经接近30;[1,2],中国电子科技集团公司第十八研究所三结GaInP/GaAs/Ge电池技术已经达到小批量生产水平.为了进一步提高多结太阳电池的转换效率,可以采用增加pn结的数量和优化三结电池子电池带宽组合等办法,但上述途径受到材料晶格匹配的限制,目前同时实现晶格匹配和最佳带宽的材料生长还存在一些问题.为此,我们采用与多结电池技术兼容的设备和材料,开展了基于AlInGaAsP材料的应变平衡量子阱太阳能电池的研究.本文给出GaAs单结量子阱电池的实验过程及结果,证实了量子阱结构的引入确实能够提高电池的输出电流.随着研究的深入,我们希望用此结构作为中间电池,以提高三结电池的效率. 相似文献
11.
12.
Reiko Azumi Kazumasa Honda Midori Goto Junji Akimoto Yoshinao Oosawa Hiroaki Tachibana 《Molecular Crystals and Liquid Crystals》2013,570(1-2):237-243
Abstract The aromatic ammonium-based layered halide compounds were obtained of bis(4-nitroanilinium)tetrachlorocadmate and bis(2-methyl-4-nitroanilinium) tetrachlorocadmate, aiming at a new type of inorganic-organic hybrid layered material. X-ray diffraction analyses of the single crystals revealed that both of the crystals take an alternate layered structure of the organic bilayer and the inorganic sheet. Cadmium ion and chloride anions form six-coordinated octahedra whose corner anions are shared with the neighboring octahedra for the crystal of bis(4-nitroanilinium)tetrachlorocadmate. In the case of bis(2-methyl-4-nitroanilinium) tetrachlorocadmate crystal the inorganic portion takes distorted four-coordinated tetrahedra. The structure of the inorganic portion for the latter crystal can be considered to be caused by the distortion of a perovskite-type octahedron due to the introduction of a bulky organic molecule. 相似文献
13.
Crystallography Reports - Molybdenum oxide is one of the most important inorganic material, which exhibits several phases, such as MoO3, MoO2, Mo4O11, Mo5O14, etc. Among them, molybdenum trioxide... 相似文献
14.
N. D. Stepina V. V. Klechkovskaya L. G. Yanusova L. A. Feigin A. L. Tolstikhina V. P. Sklizkova A. K. Khripunov Yu. G. Baklagina V. V. Kudryavtsev 《Crystallography Reports》2005,50(4):614-624
The structures have been analyzed of the monolayers of comblike precursor polymers of polyimides and mixed cellulose esters formed at the water/air interface and of the Langmuir-Blodgett films obtained by transfer of these condensed monolayers onto solid substrates. The important factors that ensure the structure control and supramolecular organization of these monolayers and films are established. 相似文献
15.
无机填料作为齿科复合树脂的主要成分,对其性能影响最为显著。本文以阿拉伯胶为结构导向剂,用热水解法合成了多孔、分级结构的刷状ZnO介晶,其厚度和直径分别为1.2 μm和1.0 μm。通过微流控制法在其表面包覆了4~6 nm无定形SiO2,以利于其表面硅烷化。通过场发射扫描电镜(FE-SEM)、X射线衍射仪(XRD)、热重分析仪(TGA)等对其进行了表征。对ZnO@SiO2进行硅烷改性处理后,将其作为辅助填料,与改性纳米SiO2主填料一起添加到Bis-GMA/TEGDMA树脂体系中,光固化得到齿科复合树脂。力学测试表明,ZnO@SiO2填充质量分数控制在5%以内时可有效提高复合树脂力学性能。与单一二氧化硅填料的复合树脂相比,添加填充质量分数3% ZnO@SiO2,复合树脂的力学性能表现最佳,其弯曲强度、弯曲模量和压缩强度分别提高了12.9%、6.6%和3.7%,同时还表现出优良的抗菌活性,对变异链球菌抗菌率达98.7%。此外,添加了ZnO@SiO2介晶填料的复合树脂还具备更好的耐磨性。 相似文献
16.
InGaAs/InAlAs in-plane superlattices (IPSLs) composed of InAs/GaAs and InAs/AlAs monolayer superlattices were grown using molecular beam epitaxy. The substrates were misoriented (110) InP tilting 3° toward the [00
] direction. We grew half monolayers of AlAs and GaAs and single monolayers of InAs alternately, keeping regular arrays of single monolayer steps. The structures were evaluated by transmission electron microscopy (TEM). In a transmission electron diffraction pattern from the (
10) cross-section, we observed two types of superstructure spot pairs double-positioned in the [001] direction, indicating the formation of the intended IPSL structures. In a cross-sectional TEM dark-field image, we observed the InGaAs/InAlAs superlattice structures formed almost in the [001] direction. The mean period of the superlattices was approximately 4 nm, which was comparable to the terrace width expected from the substrate tilt angle. However, IPSL structures were not completely formed, i.e., the lateral interfaces meandered along the growth direction, and partial disorderings were often observed. The photoluminescence spectrum from the IPSL had a peak corresponding to the InGaAs (2 nm thick)/InAlAs (2 nm thick) superlattice in addition to a peak corresponding to the In0.5Al0.25Ga0.25As alloy. 相似文献
17.
Li Li Daofeng Sun Guangru Tian Xinyu Song Sixiu Sun 《Crystal Research and Technology》2009,44(3):331-335
A new inorganic‐organic hybrid zincophosphate, [Zn(H2O)2(H2PO4)2]·2PABA ( 1 ) (PABA = p‐aminobenzoic acid), pillared by PABA ligands through hydrogen bonding interactions, has been synthesized and characterized. Single‐crystal X‐ray diffraction reveals that 1 crystallizes in the monoclinic P 21/c space group. The geometric feature in 1 is the 3D supramolecular structure constructed from alternately arranged organic and inorganic layers that consist of infinite parallel inorganic chains. These chains are extended to a 2D inorganic layer through intermolecule hydrogen bonding interactions between N atoms (from PABA ligand) and two O atoms (from adjacent inorganic chains). 1 was characterized by IR spectroscopy, XRD, DSC/TGA. The fluorescent property for 1 in solid state was also investigated at room temperature. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
18.
Peter Luger 《Crystal Research and Technology》1993,28(6):767-794
80 years after its discovery X-ray diffraction presents itself as an outstanding method in structure determination which allows the most safe and accurate geometrical data of chemical structures to obtain compared to most other experimental methods. The major innovations in the recent past and the present state of crystal structure analysis are described together with some examples in inorganic and organic chemistry, including the use of synchrotron radiation. A variety of additional applications can be considered if the diffraction experiment is executed at low temperatures. Nitrogen gas stream devices and closed cycle helium cryostats are compared and their advantages/disadvantages are discussed. Finally some applications such as low temperature crystallization, temperature dependent structure analysis down to 20 K and deformation density work are illustrated. 相似文献
19.
By reaction of di-n-alkyl 4-hydroxybenzylidene-malonates with different acid chlorides three homologous series of swallow-tailed compounds were synthesized. The products were characterized by microscopic and calorimetric investigations and show nematic and smectic behaviour. As X ray studies prove the relatively broad molecules are statistically antiparallel arranged within the smectic monolayers. 相似文献
20.
S. I. Goloudina V. V. Luchinin V. M. Pasyuta V. V. Klechkovskaya Yu. G. Baklagina V. V. Rozanov M. F. Panov V. P. Sklizkova V. V. Kudryavtsev 《Crystallography Reports》2009,54(3):468-476
The Langmuir monolayers and Langmuir-Blodgett films of a comb-like polyimide prepolymer (the rigid-chain polyamic acid alkylamine salt bearing multichains of tertiary amine) were studied. The supramolecular structures of the monolayers and Langmuir-Blodgett films of polyamic acid salts were characterized and a way for the surpamolecular structure to form was proposed based on an analysis of the surface pressure-area isotherms of monolayers on the water surface, investigations of the conditions of monolayer deposition onto solid substrates, and studies of the structures and surface morphology of Langmuir-Blodgett films. 相似文献