低阈值激光自倍频晶体Nd:GdCa4O(BO3)3

利用提拉法生长出大尺寸、高质量的激光自倍频晶体Nd:GdCa4O(BO3)3 (Nd:GdCOB).测量了Nd:GdCOB晶体的室温偏振透过谱及荧光谱,计算了其在530 nm和811 nm处沿不同主轴的吸收截面.利用电光调Q-Nd:YAG激光器,首次测试得出晶体位于XY主平面外的(θ=66.8°,φ=132.6°)位相匹配方向的有效倍频系数为2.1 pm/V;而在XY主平面内(θ=90°,φ=46°)的方向为0.7 pm/V.通过计算和实验比较,认为前者位相匹配方向为最佳倍频方向.用钛宝石连续激光器对这两个方向的样品进行自倍频实验,在520 mW的输入功率时获得绿光输出为11.3 mW,光-光转换效率为2.3%,激光阈值低于1 mW.目前θ=66.8°,φ=132.6°匹配方向在大功率钛宝石泵浦下,转换效率可以达到14.4%.     

国际水会议(IWC)论文摘要

Ｆａｒｌｅｙ核电站供水系统水处理方案的评价———ＷＩＬＬＩＡＭＥＧＡＲＲＥＴＴ ,ＪＲ ..ＡＬＡＢＡＭＡＰＯＷＥＲＣＯＭＰＡＮＹ ,ＢＩＲＭ ＩＮＧＨＡＭ ,ＡＬ .ＩＷＣ— 1999— 38　　电能研究所 (ＥｌｅｃｔｒｉｃＰｏｗｅｒＲｅｓｅａｒｃｈＩｎｓｔｉｔｕｔｅ) ,阿拉巴马电力公司 (ＡｌａｂａｍａＰｏｗｅｒＣｏｍｐａｎｙ)和Ｆａｒｌｅｙ核电站针对一种优化的次氯酸钠直供水处理方案与多种水处理方案进行了旁流评价研究。本文旨在介绍某些污垢、腐蚀和沉积结果。中国的冷却水化学品———ＱＩＮＡＩＢＡＯ ,ＳＨＡＮＧＨＡＩＰ…     

空穴凝胶色谱研究形成SBS胶束的热力学(英文)

用空穴凝胶色谱得到了ＳＢＳ胶束的临界胶束浓度以及临界胶束温度和浓度的关系，根据热力学公式计算出３０℃时形成胶束的热力学参数，发现ΔＨ°、ΔＧ°和ΔＳ°小于零。共聚物中ＰＢ含量越大，ΔＧ°和ΔＨ°越小。由于嵌段共聚物在溶液中形成了胶束，溶液的有序性增加，所以ΔＳ°减小。     

顺、反异构钼硫簇合物〔(C_2H_5)_4N〕_2〔Mo_2S_4(SCH_2CH_2S)_2〕的合成、结构和性质研究

用（ＮＨ４）２ＭｏＳ４，ＣｏＣｌ２，ＮｉＣｌ２，ＨＳＣＨ２ＣＨ２ＳＨ和Ｅｔ４ＮＢｒ在ＣＨ３ＯＨＣＨ３ＯＮａ溶液中反应，得到了顺（Ａ），反（Ｂ）异构体的原子簇化合物［（Ｃ２Ｈ５）４Ｎ］２［Ｍｏ２Ｓ４（ＳＣＨ２ＣＨ２Ｓ）２］的晶体。用Ｘ—射线单晶衍射法测定了顺、反异构体簇合物Ａ和Ｂ晶体结构，其晶胞参数Ａ为ａ＝２．６０４４（２）ｎｍ，ｂ＝１．９８８６（２）ｎｍ，Ｃ＝２．６３０２（Ｉ）ｎｍ，Ｖ＝１３．５８６ｎｍ３，β＝９３．３３°（２）；Ｂ为ａ＝１．０４４（２）ｎｍ，ｂ＝１．４１５８（２）ｎｍ，Ｃ＝１．１４１７（２）ｎｍ，Ｖ＝１．６３８ｎｍ３，β＝１００．４７°，经块距阵最小二乘法修正最终得偏离因子Ｒ＝０．０８８（Ａ），Ｒ＝０．０８９（Ｂ）。同时还对簇合物的红外光谱和紫外可见光谱也进行了研究。     

快速扩大KDP(KH_2PO_4)晶体(xy)截面的生长方法

本文提出快速扩大KDP晶体(xy)截面的生长方法。籽晶用四块z 90°切或z 45°切的晶片彼此平行地拼接而成,经过淘汰拼锥,已生长出截面为80×80mm的KDP晶体。     

Subject index :Nos 1～6 (2002)

ＧｅｎｅｒａｌＡｐｐｒｏａｃｈｔｏｄｅｓｉｇｎｏｐｔｉｏｎｓｆｏｒｌａｒｇｅ ｓｃａｌｅｈｏｍｅｍａｄｅｓｕｌｐｈｕｒｉｃａｃｉｄｐｌａｎｔｓ ＬＩＲｕｏｓｏｎｇ (1) :1Ｃｏｎｓｔｒｕｃｔｉｏｎｅｘｐｅｒｉｅｎｃｅｏｆａｌａｒｇｅ ｓｃａｌｅｓｕｌｐｈｕｒ ｐｕｒｎｉｎｇｓｕｌｐｈｕｒｉｃａｃｉｄｐｌａｎｔ ＺＨＡＮＧＺｈｉｑｉｎｇ ,ＺＨＡＮＧＷｅｎｘｉｎｇ ,ＷＡＮＧＪｉｎｇｆｅｎｇ (1) :8ＢｒｉｅｆｉｎｔｒｏｄｕｃｔｉｏｎｔｏＸｉｂｅｉＬｅａｄａｎｄＺｉｎｃＳｍｅｌｔｅｒ’ｓｓｕｌｐｈｕｒｉｃａｃｉ…     

Index To Vol22(2002)

·ＲＥＶＩＥＷ·ＡＲｅｓｅａｒｃｈｏｎｔｈｅＣｏｎｔｒｏｌｏｆＰｈｏｓｐｈｏｒｏｕｓＣｏｎｔｅｎｔｉｎＥｌｅｃｔｒｏ ｌｅｓｓＮｉ ＰＣｏａｔｉｎｇａｎｄｔｈｅＥｆｆｅｃｔｏｎｔｈｅＰｅｒｆｏｒｍａｎｃｅｓｏｆｔｈｅＣｏａｔｉｎｇ ＧＡＯＪｉａ ｑｉａｎｇ ,　ＨＵＷｅｎ ｂｉｎ( 1)∶ 1……………ＣｏｒｒｏｓｉｏｎＢｅｈａｖｉｏｒａｎｄＡｎｏｄｉｚａｔｉｏｎｏｆＭａｇｎｅｓｉｕｍａｎｄＩｔｓＡｌ ｌｏｙｓ ＪＩＡＯＳｈｕ ｑｉａｎｇ ,ＫＵＡＮＧＹａ ｆｅｉ,ｅｔａｌ.( 3 )∶ 1………ＰｒｏｇｒｅｓｓｉｎＰｌａ…     

PTC型BaTiO3陶瓷的孪晶和孪晶界

用透射电镜和高分辨电镜观察研究了PTC型BaTiO_3陶瓷的孪晶和孪晶界结构,并提出了可能的{111}孪晶及孪晶界的原子结构模型。结果表明,{111}孪晶形成氧八面体共面的共格倾斜孪晶界,在孪晶界处可能存在一定量的A空位且原子密度要低于孪晶体内。同时还发现两种其它特征的孪晶现象。     

表面活性剂和水溶性聚合物对合成A型沸石的影响(续前)

图３可以看出 ,减少体系中水含量得到的晶体成长曲线与有添加剂的曲线相似。ＡＯＴ的加入出现的效果与其他添加剂出现的效果完全相反 ,它增加了诱导期和晶化期。图４显示了不同时期晶化产品的粒度分布 ,不含添加剂的图ａ和含ＡＯＴ的图ｃ是双峰分布 ,而在其他体系中则出现较窄的单峰分布 ,表１给出了每个实验的平均晶化体积、峰晶化体积和最大晶化体积。可以看出 ,含ＳＤＳ、ＣＡＢ、Ｐ４０、ＰＥＧ和无添加剂少水的体系均比无添加剂的体系获得了较小的晶粒 ,而添加了ＡＯＴ的体系获得了较大的晶粒。表１也给出了晶体成长的线性速率 ,可以看…     

N－339炭黑填充天然橡胶与金属硫化粘接复合体剥离特性的研究

对金属－橡胶硫化粘接复合体的剥离行为进行了研究，考察了Ｎ－３３９炭黑填充量对同一粘接试样双向１８０°剥离行为的影响。结果表明：对２０～４０ｐｈｒ炭黑填充量的天然橡胶而言，同一粘接试样的双向１８０°剥离行为体现出各向同性；而当Ｎ－３３９填充量为６０ｐｈｒ时，同一粘接试样的双向１８０剥离表现为明显的各向异性。本文对这一有趣的实验现象进行了探讨，在前报的基础上提出了部分新见解。     

Nonstoichiometry and the Long-Range Cation Ordering in Crystals of (Na1/2Bi1/2) TiO3

Crystals of (Na_1/2Bi_1/2)TiO₃ have grown by the flux technique and the Czochralski method. Nonstoichiometry, twin configurations, and long-range cation ordering in the crystals have been investigated using X-ray diffraction and an optical polarizing microscope. It has been found that nonstoichiometry was induced in the crystal grown by the Czochralski method owing to the volatilization of Bi-rich phase during the crystal growth. This nonstoichiometry in the crystal resulted in less lattice distortion from cubic symmetry, a lower degree of cation ordering, and a larger domain width in twin configuration. Variations in twinning with temperature and isotropization have been investigated.     

Probing lamellar twins in spark plasma sintered CaTiO3 using Electron Backscattered Diffraction

The twinning characteristics of spark plasma sintered CaTiO₃ with orthorhombic perovskite structure is critically analysed using Electron Backscatter Diffraction (EBSD) technique. The twins are characterized by a sub-micron interlamellar spacing with a misorientation of ≈ 90°. The crystallographic relationship between the matrix and the twin has been analysed in terms of misorientation matrix using the Kikuchi patterns obtained from the EBSD scan. From the analysis of angle/axis pairs at the boundary, the twin axis was found to be of type [101]. These twins with high angle boundaries are expected to enhance fracture resistance through crack deflection and crack tip shielding mechanisms.     

Synthesis,crystal structure,photoluminescence of Ba3Y2(BO3)4:Er3+ and thermal expansion of Ba3Y2(BO3)4

The Ba₃Y_2–xEr_x(BO₃)₄ (х = 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3) phosphors were obtained by crystallization from a melt. The Ba₃Y₂(BO₃)₄ crystal structure was refined from single crystal X-ray diffraction data to R = 0.037. Its anisotropic atomic displacement parameters for all atoms were refined for the first time. The borate crystallizes in the orthorhombic crystal system, space group Pnma with unit cell parameters a = 7.673(1), b = 16.44(1), c = 8.977(2) Å, V = 1132.3(3) ų, Z = 4. These phosphors are isotypical to those of the A₃M₂(BO₃)₄ (A = Ca, Sr, Ba, M = Ln, Y, Bi) family. The crystal structure contains the isolated BO₃ triangles, two general and a special one independent crystallographic sites for large cations, which are disordered over sites. Thermal behavior of Ba₃Y₂(BO₃)₄ was investigated by high-temperature X-ray powder diffraction and thermal expansion coefficients are calculated in a wide temperature range. An inflections of temperature dependencies of the unit cell parameters is observed in a range 600–740 °C. Luminescence spectra, excitation and kinetic curves of the Ba₃Y₂(BO₃)₄:Er³⁺ series are reported. A maximum luminescence intensity is observed for the x = 0.1 sample. According to vibrational spectroscopy data no structural changes upon activation of the Ba₃Y₂(BO₃)₄ matrix with the Er ions are observed.     

The formation of multiply twinning structure and photoluminescence of well-dispersed nanodiamonds produced by pulsed-laser irradiation

The multiply twinning structure (MTS) of nanodiamonds synthesized by pulsed-laser irradiation was investigated theoretically and experimentally. The thermodynamic calculation shows MTS is more stable than single crystal structure (SCS) in a certain size range and statistical results experimentally accords with the theory. A mechanism on the formation of MTS in nanodiamonds was proposed based on Transmission Electron Microscopy (TEM) observation, in which SCS successively grows into MTS through intermediate states, such as simple twin and triple twin. Furthermore, the dispersive nanodiamonds exhibit strong photoluminescence (PL) after surface passivation.     

Observations on Growth of BaTiO3, Crystals from KF Solutions

The purpose of this study was to try to find out why BaTiO₃ (essentially a cubic structure) can consistently be grown from KF solutions as large flat plates when a more equant morphology is expected. It is suggested that the size, shape, and perfection of the platelike "butterfly" twin crystals can be qualitatively related to the re-entrant angles which result from {111} twinning of crystals of {100} habit. The re-entrant angles form permanent steps for both the advancing crystal tip and for the growth layers of the wings. The amount of twinning is related to the cooling rate and to the presence of certain impurities. Thus it can be shown that increasing the cooling rate increases the number of {111} twins (essentially a hexagonal stacking fault); the extreme case is the metastable formation of hexagonal barium titanate by quenching. Evidence is presented for the stabilization of the Ti₂O₉ group of the hexagonal structure by substitution of ions of lower polarizing power.     

Slip and Twinning in Polycrystalline Alumina (α-Al2O3) Deformed under Hydrostatic Pressure between 600° and 1000°C

The microstructure of polycrystalline alumina deformed under hydrostatic pressure and at low temperature is investigated by transmission electron microscopy. Deformation occurs mainly by prism plane slip and rhombohedral twinning. Introduction of hydrogen leads to a significant decrease in the yield stress. In large grain size alumina deformed with hydrogen, accommodation of twinning involves dislocation reactions in the twin boundary and in the grains rather than by cracking. Prism plane dislocations decompose into basal dislocations by cross slip probably due to a decrease of Peierls stress for basal slip in the presence of hydrogen.     

CVD法生长金刚石晶粒的形态

用ＳＥＭ研究了ＣＶＤ法生长金刚石晶体形态，观察到了单晶立方八面体、双晶立方八面体和两种不同形态的二十面体。晶粒上的三角形晶面多为凹坑，电有晶面上分层发育的晶层。在二十面体中，还直接地发现了倾角间隙，对于ＣＶＤ法生长的金刚石晶粒这些都是首次观察到，此外还首次观察到其它几种立方多面体晶形。     

自倍频NYAB晶体折射率n_o,n_e和折射率温度系数的测量

报道用最小偏向角和固定入射角相结合的方法测量NYAB晶体的折射率n_0,n_e,给出色散方程。另一方面也给出了n_0和n_e的温度系数的测量结果。     

Compressive Creep of Al2O3 Single Crystals

Aluminum oxide single crystals deformed by dislocation glide and deformation twinning during compressive creep at 1400° to 1700°C. The activation energy for basal slip was a function of the applied stress and agreed with activation energies previously measured by observation of yielding phenomena. The overcoming of a large Peierls-Nabarro stress is the most probable rate-controlling mechanism. Rhombohedral twinning, a significant deformation mode in creep, depends on surface damage for nucleation. The activation energy for rhombohedral twin growth, a function of the applied stress, is substantially lower than that for basal slip. When basal slip and rhombohedral twinning occur concurrently, creep by basal slip results, but the presence of twins can substantially reduce the creep rate.