Crystal Growth of 50mg-Class Single Crystals of β'-(BEDT-TTF)2ICl2 and Crystal Evaluation

Single crystals of β'-(BEDT-TTF)₂ICl₂ were grown electrochemically. In the crystal growth we used a large glass cell of which inner volume was more than 200ml. In addition, the solution was replaced by newly prepared one every two months where total period of synthesis was about one year. As a result we obtained a number of large crystals over 10mg. The weight of the largest crystal is about 50mg. The crystallinity was confirmed by X-ray topograph imaging.     

F/Cl比对PbFCl晶体生长和发光性能的影响

PbFCl是一种具有双读出功能的闪烁晶体, 性能优异但制备困难。本研究通过调整PbFCl原料组份, 探索F/Cl摩尔比(F/Cl)对晶体生长、透光和发光性能的影响。实验结果表明, 原料配方中适量富Cl有利于生长出透明晶体, 但会加剧解理。组分偏析会使晶胞参数略有改变, 而对物相没有影响。X射线激发光谱发光峰位不随F/Cl比改变而移动。透过光谱显示PbCl₂组份增加, 紫外吸收边会从300 nm蓝移至275 nm附近, F/Cl变化不引入新的吸收峰, EWT计算表明F/Cl=1:1.25时晶体的双读出性能最好。     

Content Analysis and Stability Evaluation of Selected Commercial Preparations of St. John's Wort

Content analysis and stability studies were performed for the commercial products of St. John's wort. Six marketed formulations were analyzed for their hypericin and pseudohypericin content. These products were standardized to contain 0.3% hypericin. Results revealed total hypericin as 7.72–38.57% of the labeled claim with varying concentrations of pseudohypericin. Stability studies were carried out under three different storage conditions: 1) 25 ± 2°C, 60 ± 5%RH for six months, 2) 40 ± 2°C, 75 ± 5%RH for six months, and 3) 50°C for one month. Tablet formulations were also analyzed for their hardness and friability. Stability studies revealed significant decrease in the content of the marker compounds with time.     

Characterisation and optimisation of flexible transfer lines for liquid helium. Part I: Experimental results

The transfer of liquid helium (LHe) into mobile dewars or transport vessels is a common and unavoidable process at LHe decant stations. During this transfer reasonable amounts of LHe evaporate due to heat leak and pressure drop. Thus generated helium gas needs to be collected and reliquefied which requires a huge amount of electrical energy. Therefore, the design of transfer lines used at LHe decant stations has been optimised to establish a LHe transfer with minor evaporation losses which increases the overall efficiency and capacity of LHe decant stations. This paper presents the experimental results achieved during the thermohydraulic optimisation of a flexible LHe transfer line. An extensive measurement campaign with a set of dedicated transfer lines equipped with pressure and temperature sensors led to unique experimental data of this specific transfer process. The experimental results cover the heat leak, the pressure drop, the transfer rate, the outlet quality, and the cool-down and warm-up behaviour of the examined transfer lines. Based on the obtained results the design of the considered flexible transfer line has been optimised, featuring reduced heat leak and pressure drop.     

Crystal Growth and Electrical Properties of β-CdP<Subscript>2</Subscript> Single Crystals

Optically homogeneous single crystals of tetragonal cadmium diphosphide (β-CdP₂) are prepared by vapor-phase growth, and their electrical conductivity, dielectric permittivity, and loss tangent are measured during slow heating from 78 to 400 K in the [001] and [100] directions at frequencies of 10², 10³, 10⁴, and 10⁶ Hz. The permittivity of the crystals increases with temperature. The electrical properties of β-CdP₂ are shown to be anisotropic.     

Growth and Characterization of C60 Crystals from Pure C60 and Fullerite

Good quality C₆₀ crystals have been grown from high purity C₆₀ powder and fullerene mixture (C₆₀/C₇₀) by vacuum sublimation method. The grown crystals were characterized with Optical microscopy, SEM, powder XRD, High Performance Liquid Chromatography and Raman spectroscopic analyses.     

Tm:YAP晶体生长及光谱特性研究

采用提拉法生长了掺杂浓度分别为4、8与10at%的Tm:YAP晶体. 测定了Tm³⁺在YAP基质中的分凝系数为0.88. 采用同步辐射的方法研究了Tm:YAP晶体的生长条纹和结构应力缺陷. 晶体的吸收峰位于694和795nm; 荧光谱峰值在2.0μm附近, 因此Tm:YAP晶体有望成为一种新型的适合LD泵浦的中红外激光材料.     

Ce：Cu：SBN晶体的生长及其光折变效应的研究

简述了Ｃｅ：Ｃｕ：ＳＢＮ晶体的生长,测试了晶体的衍射效率、简并四波混频位相共轭反射率和响应时间,以Ｚｎ：Ｆｅ：ＬｉＮｂＯ３晶体作为存储介质,以Ｃｅ：Ｃｕ：ＳＢＮ晶体作为自泵浦位相共轭镜,实现了实时关联存储。     

Growth evaluation of multiple interacting surface cracks. Part II: Growth evaluation of parallel cracks

In Part I of the current work, experiments on fatigue crack growth from notches and crack growth simulation for a coalesced crack with re-entrant portion were conducted. It was revealed that the growth rate in area is the same for the same applied stress and area of crack face. The main conclusion was that a crack with a re-entrant portion can be replaced with a semi-elliptical crack of the same area for the growth prediction. In this study, the influence of the interaction on the growth of semi-elliptical/semi-circular surface cracks in the parallel position was investigated. The stress intensity factor for various relative positions and shapes was evaluated by finite element analyses, and the magnitude of the interaction was quantified. Then a crack growth simulation for parallel surface cracks was developed. It was revealed that the magnitude of the interaction increases continuously during the crack growth and that, for a growth prediction, the parallel surface cracks can be replaced with a single crack of the same size on the projected plane when the relative spacing is close enough. It was concluded that the simulation can estimate the crack growth of interacting cracks and the replacement can be carried out when the offset distance is less than the crack depth.     

GdI3:Ce晶体的生长及其闪烁性能研究

通过坩埚下降法生长GdI₃:2%Ce及无掺杂GdI₃闪烁晶体, 得到ϕ15 mm×20 mm的晶体毛坯, 从中加工出尺寸分别为12 mm×10 mm×2.5 mm和11 mm×8 mm×2.5 mm的无包裹体、无开裂的晶体样品, 封装后检测该晶体光学性能。XRD分析结果表明: 掺杂晶体GdI₃:2%Ce与无掺杂GdI₃晶体结构相同。X射线激发发射(XEL)和紫外激发发射谱(PL)测试结果显示: GdI₃:2%Ce晶体在450~700 nm有宽带发光峰, 发光峰位分别位于520 nm和550 nm, 对应于Ce³⁺的5d-4f跃迁发光。以550 nm为监控波长, 测得在紫外激发下存在三个激发峰, 分别位于262、335和440 nm。GdI₃:2%Ce晶体在¹³⁷Cs源伽马射线(662 keV) 激发下能量分辨率为3.4%, 通过高斯拟合得到的衰减时间为58±3 ns。研究表明, GdI₃:2%Ce晶体是一种良好的伽马和中子探测材料, 具有广泛的应用前景。     

Growth of Structurally Perfect Diamond Single Crystals at High Pressures and Temperatures. Review

The investigations performed at high pressures and high temperatures (HTHP crystallization) have permitted clarifying the mechanism of phase transformations and carbon transport in solvent metals for diamond growth and elaborating methods for growing large-size structurally perfect diamond single crystals of types Ib, IIa, and IIb. The findings have provided the basis for the process of production of diamonds for applications in electronics, laser technology, precision machining operations, well drilling tools. The use of a large-volume six-punch high pressure apparatus makes it possible to grow diamond single crystals with a higher efficiency. It is estimated that this apparatus is capable of producing annually at least 1 mln carats of structurally perfect crystals of required types for various applications.     

Ce:Cu:SBN晶体的生长及其自泵浦位相共轭效应的研究

在铌酸锶钡中掺入ＣｅＯ２和ＣｕＯ，生长了Ｃｅ：Ｃｕ：ＳＢＮ晶体，测试了该晶体的衍射效率、自泵浦位相共轭反射率和响应时间。以Ｃｅ：Ｃｕ：ＳＢＮ晶体作为自泵浦位相共轭镜，以Ｚｎ：Ｆｅ：ＬｉＮｂＯ３晶体作为存储介质，实现了实时关联存储。     

硅熔体中碳化硅熔解与硅晶体中碳化硅生长

工业生产的太阳能电池用多晶硅锭内部常出现碳化硅夹杂,影响太阳能电池的转换效率,特别是严重威胁硅片的切割生产过程。本文研究了硅熔体中碳化硅熔解与硅晶体中碳化硅沉淀生长特性。在熔解实验中发现:即使在碳显著过饱和的情况下,碳化硅仍会熔解在1450℃的硅熔体中,同时熔体中易形核处发生新的碳化硅颗粒析出。在1350℃下进行了硅料中碳化硅沉淀的固相生长实验,结果表明晶体硅中碳化硅沉淀的高温固态生长十分缓慢。这一特性得到理论计算证实,它表明固相生长不可能是多晶硅锭中出现大颗粒碳化硅的原因。     

Crystal growth of alkaline earth fluorides in a reactive atmosphere. Part II

Crystal growth of MF₂ (M = Ca, Sr, and Ba) is carried out under two different reactive atmospheres, HF and HF + CF₄, with the same carrier gas (He). The effect of processing is seen in a comparison of the optical transparency in the near infrared of the single-crystal specimens.     

Crystal growth of alkaline earth fluorides in a reactive atmosphere. Part IV

SF₆, CF₄, and BF₃ are compared as gas-phase reactants of reactive atmosphere processing (RAP) in the crystal growth of alkaline-earth fluorides. To varying degrees, all three agents are corrosive to carbon at the crystal-growth operating temperature of 1500°C. The corrosion rate decreases with an increase in the fluorine bond dissociation energy of the gas-phase reactant.     

Dissolution Characteristics of Interactive Powder Mixtures. Part One: Effect of Solubility and Particle Size of Excipients

Abstract

Interactive mixtures of fine cohesive drug powders and coarse free flowing excipients are reported to increase dissolution rates of poorly soluble drugs. However, dissolution rates are known to be affected by the solubility characteristics of the excipients as well as excipients surface characteristics after mixing with lubricant.

In this study the effects of solubility and particle size of excipients on dissolution of micronized griseofulvin from interactive powder mixtures were investigated. Quantitative assessment of dissolution from such mixtures showed that systems containing soluble excipients increased dissolution of the drug more efficiently than mixtures prepared using insoluble excipients. The role of the soluble excipient was more significant after mixing with magnesium stearate. Excipients of smaller particle sizes increased dissolution more efficiently than their large size counterparts. Effects of particle size were particularly significant in case of water insoluble excipients.     

Growth of controlled profile crystals from the melt: Part I - Sapphire filaments

A crystal growth technique is described in which a tubular, annular, or ribbon-shaped capillary orifice is used to maintain the liquid level constant during growth and to determine the shape of the growing crystal. The orifice material must be wetted by, but chemically nonreactive to the molten phase of the crystal to be grown. Using molybdenum orifices and crucibles, single crystal sapphire filaments several hundred feet in length and diameters of .01 - .05 cm have been grown at speeds of 2.5 - 5 cm/min; c-axis crystals have been grown at rates up to 20 cm/min, and a variety of other crystal orientations has been grown at speeds up to 2.5 cm/min. Sapphire tubes, ribbons and multiple filaments have also been grown.     

Peculiarities of Short Fatigue Crack Growth from a Blind Hole in Specimens Made of Steel 45. Part 2. Model of Short Fatigue Crack Growth from a Notch

Strength of Materials - A model to describe the kinetics of short fatigue crack growth from an obtuse stress raiser (notch) is proposed. The model makes it possible to calculate the kinetic diagram...