Synthesis and Crystal Structure of （R）-4-Hydroxymethyl-2-thioxo Thiazolidine and Its Asymmetric Catalysis

(R)-4-Hydroxymethyl-2-thioxo thiazolidine as a new chiral catalyst in the asymmetric addition of diethyl-zinc to benzaldehyde was synthesized from (R)-4-hydroxymethyl-2-thioxo thiazolidine carboxylic acid and its crystal structure was determined by X-ray diffraction method. The compound was crystallized in the orthorhombic system, space group P212121 with unit cell dimensions a=0.67253(12) nm; b=0.89164(17) rim; c=1.06146(19) nm, volume 0.6365(2) nm3; Z=4, calculated denisity 1.557 Mg/m3; absorption coefficient 0.733 mm-1; F(000)=312. The X-ray crystal structure analysis reveals that the compound has a thione group.     

ESTIMATION OF SULFUR SOLUBILITY AND PREDICTION OF SULFIDE LIQUID IMMISCIBILITY IN SILICATE MELTS

A set of 201 experimental data on solubility of sulfur in silicate melts was collectedfrom literature to formulate the changes of sulfur solubility as a function of bulk compo-sition of the melts and pressure, temperature, and the fugacity of oxygen and sulfur. Aregular solution model and a polynomial function have been put forward, from which sol-ubility of sulfur in natural silicate magmas can be estimated. Synthetic application of twomethods makes it possible to evaluate activity of FeS in a silicate melt, which will be po-tentially valuable for predicting immiscibility of sulfide liquid in magmatic processes.     

EFFECT OF SIMULATED WEIGHTLESSNESS ON THE RESPONSE CHARACTERISTICS OF HUMAN BRAIN

In order to systematically investigate the effects of simulated weightlessness on thefunction state of human brain, 15° head-down tilt (HDT) was used to simulate weightless-ness, and the response changes of event-related EEG power spectra, medium-frequencysynchronous potentials and slow-waves were examined in the present study. It was foundthat HDT had characteristic effects on the above EEG responses, suggesting that the ef-fects mainly occurred in the brain's regulatory system, therefore, resulting in changes ofthe brain function state.     

多光束全息互连元件效率的理论分析

多光束全息互连元件往往需要大量的耦合波方程才能描述。本文通过分析记录时生成的互调制光栅的性质及其对衍射的影响,对问题进行适当的简化。通过解不同条件下的耦合波方程、分别给出了多光束全息图在各种不同情况下的衍射效率的近似解析表达式,展示了衍射效率与各实验参量之间的关系。为进一步研究多光束全息互连元件的性质、比较各种条件下的效率以及各参量对总体效率的影响,提供了方便。     

强激光对铜反射镜的热破坏效应

本文给出了一个激光对光学材料表面热破坏效应的简化物理模型及数值研究结果。所得到的铜反射镜热破坏阈值与激光脉宽的关系与实验和理论符合很好。提出了反射镜后表面外冷却临界厚度的概念,并得到一个关于多脉冲积累效应的幂定标关系。     

S-curvature of isotropic Berwald metrics

Isotropic Berwald metrics are as a generalization of Berwald metrics. Shen proved that every Berwald metric is of vanishing S-curvature. In this paper, we generalize this fact and prove that every isotropic Berwald metric is of isotropic S-curvature. Let F = α + β be a Randers metric of isotropic Berwald curvature. Then it corresponds to a conformal vector field through navigation representation.     

A SET OF SYMMETRIC QUADRATURE RULES ON TRIANGLES AND TETRAHEDRA

We present a program for computing symmetric quadrature rules on triangles and tetrahedra. A set of rules are obtained by using this program. Quadrature rules up to order 21 on triangles and up to order 14 on tetrahedra have been obtained which are useful for use in finite element computations. All rules presented here have positive weights with points lying within the integration domain.     

Size effect of fullerene cages and encaged clusters in M_3N@C_(2n)

Based on the calculated findings that the sizes of encaged clusters determine the structures and the stability of C80-based trimetallic nitride fullerenes (TNFs), more extensive density functional theory calculations were performed on M3N@C68, M3N@C78 and M3N@C80 (M=Sc, Y and La). The calculated results demonstrated that the structures and stability undergo a transition with the increasing of the sizes of the cages and clusters. Sc3N is planar inside the three considered cages, Y3N is slightly pyramidal ins...     

Investigation of Microemulsion System for Transdermal Drug Delivery of Amphotericin B

In order to solve the drawback of poor bioavailability by the oral route and infusion-related side effect for Amphotericin B(AmB), microemulsion vehicles composed of isopropyl myristate(IPM), Tween 80, isopropyl alcohol and water for transdermal delivery of AmB were designed. The pseudo-ternary phase diagrams were constructed by the H2O titration method and the structures of the microemulsion were determined by measuring electrical conducti-vities(σ). The diffusion studies of AmB microemulsion were performed via excised rabbit skin on a drug diffusion apparatus. To obtain a high solubization of AmB, three different methods were tested to incorporate AmB into mi-croemulsion. The result suggests adding AmB in the shape of NaOH solution to the O/W blank microemulsion over the phase inversion temperature(PIT) of the emulsifier obtains the maximum drug content(2.96 mg/mL). The pH value of the system could be adjusted to pH8.5 or pH<5.2, in this range AmB molecules converts from aqueous to the hydrophilic shell of the microemulsion droplets, drug precipitate is no more than 5%, and the formulations were corresponding to the characterizations of microemulsion. At pH 5.14, AmB microemulsion with Km 1:1, O/SC 1:9(mass ratio ofoil phase to surfactant/cosurfactant blend), water content 64.6%, drug content (2.93±0.08) mg/mL,showed the maximum permeation rate(3.255±0.64)μg·cm-2·h-1,which is stable for a long time.