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1.
采用Cz法生长了高温相偏硼酸钡α-BaB2O4晶体,尺寸为φ50mm×40mm,晶体无色透明,在He-Ne激光照射下无散射颗粒,无生长条纹.在生长过程中,α-BaB2O4晶体存在强烈的晶面显露特性,主要与晶体所属点群R-3c有密切关系,本文采用周期键链PBC理论分析了α-BaB2O4晶体的结晶习性.在实验上根据晶面夹角的关系,结合X射线劳埃衍射照相的方法标定了晶体的显露面指数,两者很好地吻合.α-BaB2O4晶体主要存在了3组显露面即三方锥面S{1-102}、六方柱面P{11-20}和菱面体T{21-34},且显露顺序为S>P>T,三方锥面S与六方柱面P的晶棱方向为[-1101],三方锥面S与菱面体T面的晶棱方向为[-4223],在晶体放肩部位处有对称分布的6条晶棱,分别对应于两组晶向[10k1i],[11k2i],i=1,2,3在一般情况下,k1i≠12i. 相似文献
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水热法合成α-Al2O3晶体的晶面形态 总被引:4,自引:1,他引:3
本文研究了高温高压水热法合成α-Al2O3晶体的形状和表面形态.原料为Al(OH)3,矿化剂的浓度为1M KBr、0.1 M KOH,填充度35;, 温度388℃时,可部分自发生成α-Al2O3晶体.温度超过395℃以上,可全部转化成α-Al2O3晶体,晶体形状为六棱柱体,显露底面{0001}和柱面{21 10}、{1120}、{1210},晶体的表面呈现阶梯.在矿化剂为1M KOH,填充度35;,温度为380℃时,部分自发生成α-Al2O3晶体,晶体的底面{0001}和柱面{1120}消失,呈现双锥形;当温度达到395℃时,可全部转化成α-Al2O3晶体,晶体呈双锥形,晶面呈条状阶梯形;温度达到405℃以上,晶体又呈现六棱柱体. 相似文献
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In掺杂对水热法合成ZnO晶体形貌的影响 总被引:1,自引:0,他引:1
本文采用水热法,在ZnO中添加In2O3为前驱物,3mol/L KOH作矿化剂,温度430℃,填充度35;,反应24h,制备了掺In的ZnO晶体.未掺杂In2O3合成的纯ZnO晶体呈六棱锥状,显露负极面-c{0001}、六棱锥面+p{1011}和-p{1011},一般不显露{0001}面.前驱物中掺杂In2O3所合成的ZnO晶体呈六角片状,直径约为5~20 μm,大面积显露{0001}面,另外还显露正锥面+p{1011}、负锥面-p{1011}和负极面-c{0001}.由此可见In掺杂可以明显的改变晶体的形态,使c轴极性快速生长趋向得到明显改善,有利于降低晶体生长缺陷.当采用ZnO晶片为籽晶时,通过水热反应在晶片上生长了一层掺In的ZnO薄膜,通过Hall参数测量得到晶体膜层的电子迁移率约为22cm2/(V·s),载流子浓度约为2×1020 cm-3,具有良好的导电性,同时也说明In可以微量掺入氧化锌晶体. 相似文献
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氧化锌单晶的水热生长与结晶习性 总被引:1,自引:1,他引:0
本文应用水热生长法,采用双温区高压反应釜,黄金内衬(φ35mm ×2mm),碱性溶液矿化剂,生长出了毫米级的透明氧化锌单晶,最大单晶可达2mm ×3mm ×6mm.所生长氧化锌晶体为纤锌矿型的六方晶体,晶体呈上部锥形的六棱柱体,{10(1-)1}、{10(1-)0}和{000(1-)}面有较大的显露平面.本文中从温差和填充度方面研究了实验条件对ZnO晶体的生长及其形貌的影响,使用黄金内衬前后的结果表明,用贵金属内衬可以有效阻止釜内壁杂质的进入,使晶体完整透明. 相似文献
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本文进行了Yb3+∶FAP与Yb3+∶YAG的对比分析,指出了在激光核聚变领域中Yb3+∶FAP是很有希望的增益介质,针对Yb3+∶FAP吸收光谱宽度很小(4nm)对泵浦源要求苛刻,采用Yb3+∶CS-FAP即以部分Sr2+代替Ca2+造成Yb3+周围环境多样性增加、增加谱宽.参考分析了Ca3(PO4)2-CaF2体系的相图,推测出生长CS-FAP晶体的配料区间,给出了生长晶体的原料制备方法,采用氮气流动、白宝石片封闭保温罩的观察孔和观察窗上贴石英片相结合有效地缓解了在晶体生长过程中组分挥发、开裂、以及氟化物腐蚀窗口等一系列问题.生长工艺参数为:提拉速度1~3mm/h,旋转速度10~20r/min,在流量为20ml/min的流动N2中生长,采用尺寸为60×40mm的Ir坩埚进行生长,线圈尺寸为内径130mm×130mm×8圈,外径155mm×95mm×6圈.得到了尺寸为10mm×20mm的高质量晶体.用X射线粉末衍射分析证明所生长的晶体结构正确. 相似文献
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采用水热法,在ZnO中添加SnCl2.2H2O作前驱物,3M KOH作矿化剂,温度430℃,填充度35%,反应24h,合成了掺杂Sn的ZnO晶体。当前驱物中添加SnCl2.2H2O可以明显影响部分晶体形态,使正极面c轴方向的生长速度受到抑制,较大面积显露正极面c{0001},同时也显露负极面-c{000 1}、正锥面p{10 10}、负锥面-p{101 1}和柱面m{10 10}。磁性测量结果显示Sn可微量掺入ZnO晶格中,且呈现顺磁性特征。X射线衍射和X光荧光能谱分析表明,SnCl2.2H2O的添加量较大时,还伴随生成金红相SnO2棒状晶体。 相似文献
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本文采用自发成核助熔剂法生长深紫外非线性光学晶体RbBe2BO3F2(RBBF)。研究了不同助熔剂体系的黏度对自发成核的影响,采用Rb2O-NaF-B2O3体系获得了厚度超过2.5 mm的大块透明RbBe2BO3F2晶体。研究了晶体的热学性能,包括熔点、比热、热膨胀系数和热导率,并与KBBF同族晶体进行了比较。在30~300℃温度范围内,RBBF晶体比热是0.70~0.95 J/g·K,大于CBBF晶体。测得RBBF晶体沿c轴的热膨胀系数是z=47.16×10-6K-1,在298 K时沿c轴的热导率是3.04 W/m·K。 相似文献
8.
本文采用水热法,以ZnO为前驱物,添加适量的MnCl2·4H2O、SnCl2·2H2O和MnCl2·4H2O、CoCl2·6H2O、CuCl2·2H2O,3 mol/L KOH作矿化剂,430℃反应24 h,分别合成了Zn1-xMnxO:Sn晶体和Zn1-x-yMnxCoyO:Cu晶体.用扫描电镜(SEM)对合成物形貌进行分析,结果表明,Zn1-MnxO:Sn晶体为六棱柱状晶体,直径约为10 μm,较大面积显露正极面c{0001},同时也显露负极面-c{0001}、正锥面p{1011}、负锥面-p{1011}和柱面m{1010}.Zn1-x-yMnxCoyO:Cu晶体也显露负极面-c{0001}、正锥面p{1011}、负锥面-p{1011}和柱面m{1010},{0001}显露面小于{0001}.X射线能谱(EDS)分析表明晶体主要成分为ZnO,Mn2 、Co2 离子掺杂量超过2%;SQUID磁性测量显示所合成晶体在25 K具有反铁磁特征,高温为顺磁性. 相似文献
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本文采用水热法,以3mol/L KOH为矿化剂,填充度35;,温度430℃,在Zn(OH)2中添加SnCl2·2H2O,添加量为Sn2+:Zn2+=2;条件下,合成出ZnO晶体.产物中除了大量短六棱柱形晶体外,还出现了部分冰激凌形晶体.六棱柱形晶体具有典型的ZnO特征,显露正极面c{0001}、负极面-c{000-1}、柱面m{10-10}、正锥面p{10-11}和负锥面-p{10-1-1}.而冰激凌形晶体有明显的六棱锥晶体外壳,X光能谱(EDS)检测证实晶体各部位的组分均为ZnO. 相似文献
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Some crystals of [Nd(H2O)2]2(C2O4)3 were synthesized hydrothermally by heating at 200°C for 8 days an aqueous suspension of neodymium oxalate decahydrate in presence of terephthallic acid and guanidinium carbonate. They crystallize in the orthorhombic system, space group P212121, with a = 8.6702(7) Å, b = 9.558(2) Å, and c = 17.009(2) Å. The structure of this complex is built up by two independent neodymium atoms, three bischelating oxalate ligands, and four water molecules forming a rectangle building unit of 6-membered ring, [Ln(H2O)2(C2O4)]6. The packing of these units leads to a layer parallel to the plane (001). However, the neodymium atoms of two neighbor layers share an edge of oxalato oxygen atoms thus giving a double-layer. The three dimensionality between these double-layers is insured by hydrogen bonds of water molecules which are bound to the neodymium atoms. There is no zeolitic water molecule. The two neodymium atoms are nine-coordinated. In both cases, the coordination polyhedron can be described as a distorted tricapped trigonal prism. 相似文献
13.
采用高温溶液法生长了准同型相界(MPB)四元弛豫铁电单晶Pb(Sc1/2Nb1/2) O3-Pb(Mg1/3 Nb2/3)O3-PbTiO3-PbZrO3,得到较大尺寸且具有规则外形的立方单晶.研究结果表明所生长的晶体为钙钛矿结构,立方晶粒平整的暴露面均为(001)面;晶体以层状方式生长,生长机制为搭桥生长;所生长晶体的矫顽场Ec~3.52kV/cm,三方四方相变温度Tr-t~104℃,居里温度Tc~149.5℃,压电常数d33~1089 pC/N,剩余极化强度Pr~25.4 μC/cm2;随着频率增加,晶体的相变弥散度减小. 相似文献
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Ruan Yongfeng Zhang Shouchao Li Guanghui Zhu Wei Wang Danli Zhang Lingcui 《Crystal Research and Technology》2010,45(5):562-566
Single crystals of Erbium (Er) doped BaY2F8 have been obtained by the temperature gradient technique (TGT). No‐seed‐grown crystal of Er:BaY2F8, with the dimensions up to several centimeters, was obtained by self‐crystallization. The optimizations of various growth parameters were systemically investigated. The results indicated that the temperature gradient of 6‐7 K/mm and the cooling velocity less than 6 K/h were suitable for the crystal growth. The XRD data and the investigations on the growth striations by a stereo polarization microscope displayed that the [001] direction is the dominating direction for the crystal growth. The crystal grown by TGT often cracks along with the (100) plane, which is caused by the excessive decrease of the temperature during the crystal growth, for there is a rapid change in the thermal expansion curve of the BaY2F8 crystal in the temperature range from 800 °C to 900 °C. The spectral properties of Er:BaY2F8 single crystals have been studied and the effects of frequency up‐conversion of the crystals are reported. Spectral data suggest that the quality of Er:BaY2F8 crystal obtained by TGT method is good and the crystal has the potential application in laser devices. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
17.
Avinash Kumbhar Pramila Sonawane Subhash Padhye Douglas X. West Ray J. Butcher 《Journal of chemical crystallography》1997,27(9):533-539
The structures of two antitumor agents, 2-acetylpyridinethiosemicarbazone hemihydrate (1), C18H11N4O0.5S, colorless,M r 203.3, monoclinic,P21 lc,a=16.713(3),b=9.460(2),c=12.642(2) Å, β=97.60(1)°,V=1981.2(6) Å3,Z=8,R=0.054,R w =0.085 and 2-acetylpyridinethiosemicarbazone hydrochloride (2), C18H12N4SCl, yellow,M r =230.7, monoclinic,P21 ln,a=7.676(2),b=7.889(1),c=17.452(4), Å, β=100.96(2)°,V=1037.5(4) Å3 Z=4,R=0.041,R w =0.076, have been determined. Both compounds exhibit an E configuration(S atomtrans to the N atom of the hydrazine group). Three hydrogen bonds link the two crystallographically independent molecules in a pairwise fashion in the hemihydrate. An intramolecular N?H...Cl bond lends extra conformational stability to the hydrochloride salt. 相似文献
18.
Avinash Kumbhar Pramila Sonawane Subhash Padhye Douglas X. West Ray J. Butcher 《Journal of chemical crystallography》1991,27(9):533-539
The structures of two antitumor agents, 2-acetylpyridinethiosemicarbazone hemihydrate (1), C18H11N4O0.5S, colorless,M
r
203.3, monoclinic,P21
lc,a=16.713(3),b=9.460(2),c=12.642(2) ?, β=97.60(1)°,V=1981.2(6) ?3,Z=8,R=0.054,R
w
=0.085 and 2-acetylpyridinethiosemicarbazone hydrochloride (2), C18H12N4SCl, yellow,M
r
=230.7, monoclinic,P21
ln,a=7.676(2),b=7.889(1),c=17.452(4), ?, β=100.96(2)°,V=1037.5(4) ?3
Z=4,R=0.041,R
w
=0.076, have been determined. Both compounds exhibit an E configuration(S atomtrans to the N atom of the hydrazine group). Three hydrogen bonds link the two crystallographically independent molecules in a
pairwise fashion in the hemihydrate. An intramolecular N−H...Cl bond lends extra conformational stability to the hydrochloride
salt. 相似文献
19.
有机锡配合物{[~nBu_2Sn(OOCC_5H_3(NO_2)_2)]_2O}_2的合成、谱学表征和晶体结构 总被引:1,自引:0,他引:1
以3,5-二硝基苯甲酸和二丁基氧化锡为原料,合成了一种新的有机锡配合物{[~nBu_2Sn(OOCC_5H_3(NO_2)_2)]_2O}_2,并对其进行了元素分析、红外光谱表征和X射线单晶衍射.结果表明:该配合物属三斜晶系,P_ī空间群,a=1.0705(2) nm,b=1.3333(3) nm,c=1.4360(3) nm,α=68.892(3) °,β=78.297(3) °,γ=80.285(3) °, V=1.8620(7) nm~3 , Z=1, dc=1.613 g/cm~3 , μ=1.406 mm~(-1), F(000) =908, R_1=0.0408, wR_2=0.0948.该化合物分子是以Sn_2O_2四元环为中心,对称的二聚体结构,内外环锡原子均为五配位的畸变三角双锥构型. 相似文献
20.
Slaheddine Chaabouni Slaheddine Kamoun Abdelaziz Daoud Tahar Jouini 《Journal of chemical crystallography》1997,27(7):401-404
The pentakis ethylenediammonium bis undecachlorodiantimonate(III) tetrahydrate salt is monoclinic with the following unit
cell dimensions:a=16.271(5) Å,b=13.004(4) Å,c=13.932(4) Å, β=111.72(2)°, space groupP21/c withZ=2. The structure was solved by Patterson methods and refined to a finalR value of 0.023 for 4435 reflections withF
0>4σ(F
0). The structure shows a layer arrangement perpendicular to thea axis: planes of the [Sb2Cl11]5− bioctahedra alternate with planes of [NH3(CH2)2NH3]2+ dications. The [Sb2Cl11]5− bioctahedra are connected through O−H...Cl hydrogen bonds, such that infinite chains of composition [Sb2Cl11(H2O]n
5n− are formed in the structure, parallel to the twofold axis. These chains are themselves interconnected by means of N−H...Cl
and O−H...Cl bonds originating from the [NH3(CH2)2NH3]2+ entities and the water molecules, respectively, and form a threedimensional network. 相似文献