Decay of neutron-rich Ga isotopes near N = 50 at PARRNe

The PARRNe facility has been used to produce neutron-rich isotopes ^83,84Gaby the ISOL method. Their decay has been studied, and β-γ coincidence and γ-γ coincidence data were collected as a function of time. The first two excited levels in ⁸³Ge and the first excited level in ⁸⁴Ge have been measured for the first time.     

光参量啁啾脉冲饱和放大的增益稳定性

 光参量啁啾脉冲放大（OPCPA）在饱和放大区存在一个增益稳定点，据此设计了一个输出稳定的三级OPCPA系统；第一、二、三级分别选用准相位匹配的周期极化钛氧磷酸钾（PPKTP）晶体、LBO晶体和KDP晶体作为增益介质。饱和放大时，增益随泵浦光强度变化时的增益输出稳定性明显改善，在泵浦光强度抖动低于6%的情况下，各级光参量放大器OPA输出的增益抖动小于1%。前级采用准相位匹配的PPKTP晶体作为增益介质，在远低于破坏阈值的30MW/cm²的泵浦功率密度下，可得到2×10⁵的饱和放大增益和20%的能量转换效率。     

Cr3+：MgAl2O4晶体EPR参量及其电子精细光谱的研究

考虑了SS(Spin-Spin)作用和SOO(Spin-Other-Orbit)作用，采用完全对角化方法，结合自旋Hamiltonian理论，研究了Cr³⁺∶MgAl₂O₄晶体EPR参量及其吸收光谱，理论与实验符合甚好. 在此基础上，进一步研究了⁴A₂(3d³)离子EPR参量的微观起源. 研究表明，EPR参量起源于四种微观机制：(1) SO(Spin-Orbit) 耦合机制；(2) SS耦合机制；(3)SOO耦合机制；(4) SO～SS～SOO总联合作用机制. 在这些机制中，SO机制是最主要的.     

多目标优化发射层析算法在等离子体场光谱诊断中的应用

提出一种基于多目标优化原理的发射光谱层析(EST)图像重建新算法MCIRT.通过计算机数值 模拟，考察了该算法对非对称发射系数场分布的重建效果.结果表明，与传统层析算法相比 ，MCIRT算法具有收敛快，重建精度高的优势，适合于非完全数据情况下的等离子体发射系 数场重建，并且实时性更好.作为一个应用实例, 运用谱线相对强度法重建了自由电弧等离 子体的三维温度及粒子数密度分布. 关键词： 等离子体诊断 图像重建     

The Crystal Structure of N-Benzoyl-N''-(2-hydroxyethyl)-thiourea

Thiourea compounds are excellent agents of bioactive substance. A number of biological activities are associated with substituted thiourea derivatives. A survey of literature reveals that some work has been reported on benzoylthiourea, which has found plenty of applications as a facile and simple ligand in determination of trances of the transition metal and as an available starting material in preparation of a wide variety of metal complexes. In recent years,N-benzoyl-N'-(2-hydroxyethyl)-thiourea has attracted considerable attention as selective reagents for the liquid-liquid extraction and preconcentration of platinum group metals and its antifungle activity.As a part of our works in studying coordination behaviours of N-benzoyl-N'-(2-hydroxyethyl)-thiourea and its bioactivity, in view of these observations and in continuation of our previous works on it, the present work was reported on the crystal structure of N-benzoyl-N'-( 2-hydroxyethyl)-thiourea.The crystals structure in the monoclinic system and space group of P21/c of N-benzoyl-N'-(2-hydroxyethyl)- thiourea (C10H12N2O2S) was determined from single-crystal X-ray diffraction analysis, a = 17.083 (3) A, b = 4.5490 (10) A, c = 14.279 (3)A, a = 90.00°, a = 102.44(3)°, a = 90.00 °, Ⅴ = 1083.6 (4)A3, Z = 4, Dc = 1.375 Mg/m3, i (Mo Ka)= 0.280 mm-1, F(000) =472. The final R and u R are 0.0399 and 0.0881 for 783 observed reflections [Ⅰ＞26(Ⅰ)].Fig. 1 shows the molecular crystal structure of N-benzoyl-N'-(2-hydroxyethyl)thiourea indicating that the carbonyl and thiocarbonyl moieties are pointing in approximate opposite directions. The six atoms in the ring structure hydrogen bonded are almost in one plane. The N(2)-H proton pendant arm extends to the carbonyl oxygen atom, forms hydrogen bond between them.The existence of hydrogen bond in benzoyl-thiourea molecular six-membered ring structure has significant implications on coordination properties, suggest the possibility of intramolecular hydrogen bond controlled coordination behaviors of these potentially bidentate ligands. In the coordination compound reported by Bourne et al.,cis-bis(N-benzoyl-N'-propylthiourea)dichloroplatinum(Ⅱ), the two ligand molecules bind to Pt(Ⅱ)via the sulfur atoms only, the carbonyl oxygen atom being locked into hydrogen bond similar to that in the free ligands.     

Synthesis under Micromave Irradition and Crystal Structure of 4''-Acetylbenzo-15 -crown-5thiosemicarbazone

The title compound is a bifunctional receptors including a thiourea group and a crown ether ring. Due to many possible potentials as a new class of reagents for membrane transports,ion-selective electrodes as well as reaction catalysts, the design and synthesis of bifunctional receptors for simultaneous binding of cations and anions is of ongoning interest in srprarnolecular chemistry1-5. In bifunctional receptors, the binding sites for anions and cations are covalently linked so as to exhibit allosteric or cooperative complexation where the binding affinity for anions(cations)is modified as a result of the cation(anion) complexation.Literature[6] reported that the ability of the thiourea group to bind anions is significantly enhanced when Na+ is bound to the crown moiety. To date, however only a few receptors of this class have been reported.6-8In this paper, we report an improved procedure under microwave irradiation that gives higher yields of title compound and needs fewer reaction times than traditional method.The structure of this compound was determined by IR ,element analysis and X-ray analysis.Scheme 1 The reaction equationThe crystal belongs to triclinic crystal system, P-1 space group, a=0.9547(0)nm, b=1.3637(3)nm,c=1.6029(3)nm, α =75.33(3) , β =83.62(3) , γ =70.99(3) ,Z=4,Dc=1.335g/cm3,F(000)=816,R1= 0.0557 ,wR2=0.1281. It is assembled into a three-dimensionalsupramolecule by intermolecular hydrogen bonds.     

Synthesis of new terpene derivatives via ruthenium catalysis: rearrangement of silylated enynes derived from terpenoids

Enyne rearrangement of silylated modified terpenoids has been used as the key step for the synthesis of new terpenes and terpenoids. The catalytic system generated in situ from [RuCl₂(p-cymene]₂, 1,3-bis(mesityl)imidazolinium chloride and cesium carbonate is able to perform the transformation of silylated 1,7-enynes into cyclic siloxanes. Selective cleavage of the silicon-carbon and silicon-oxygen bonds by simple reactions has been performed to afford new terpenes and terpenoids by formal addition of a C5 unit.     

模拟纳米晶体原子分布及X射线散射理论图案

通过分子动力学方法模拟纳米晶体（1—3nm）的结构．利用模拟的结果，进行了X射线衍射及径向分布函数的模拟计算．结果表明：纳米晶体晶界呈短程有序，界面原子间距分布很宽；随着晶粒尺寸的减小，晶粒的畸变越大，原子体积常数也明显增大 关键词：     

Study of the gas-phase parameters affecting the silicon-oxide film deposition induced by an ArF laser

A study of the gas-phase parameters involved in ArF laser induced chemical vapour deposition of silicon-oxide thin films is presented. A complete set of experiments has been performed showing the influence of the concentration of the precursor gases, N₂O and SiH₄, and their influence on total and partial pressures on film growth and properties. In this paper we demonstrate the ability of this LCVD method to deposit silicon oxide films of different compositions and densities by appropriate control of gas composition and total pressure. Moreover, a material specific calibration plot comprising data obtained using different preparation techniques is presented, allowing determination of the stoichiometry of SiO _x films by using FTIR spectroscopy independently of the deposition method. For the range of processing conditions examined, the experimental results suggest that chemical processes governing deposition take place mainly in the gas phase.     

Optical detection of NO3 and NO2 in “pure” HNO3 vapor,the liquid-phase decomposition of HNO3

Flowing and static gas-phase samples of HNO₃ in O₂ and N₂ were analyzed by long-path ultraviolet/visible (UV/VIS) spectroscopy to reveal the presence of both NO₂ and NO₃, the concentrations of which were calculated using differential absorption cross sections. NO₂ is produced predominantly by the heterogeneous decomposition of HNO₃, whereas NO₃ is generated in the gas phase by the thermal decomposition of N₂O₅, a product of the self-disproportionation of liquid HNO₃. © 1993 John Wiley & Sons, Inc.