银锌合金中的β相变

Owen与Edmunds曾经指出:银锌合金Ag-Zn由β相区骤冷后得到有序的体心立方结构β′相;缓冷则得到六角晶系ζ相;但在β相区进行高温观察,则只得无序的体心立方结构β相(图1)。然而对于相变机构及超结构β′相的性质他们并未说明。     

含有50原子%Zn的Ag-Au-Zn合金的研究

合金AgAuZn₂具有一个与郝斯勒合金同晶型结构的β″相,这个β″相存在于一个相当广阔的成分范围里。事实上,β″相就是β′有序结构的超结构。伴随着,β″结构的形成晶格发生突然的收缩。关于Ag-Au替换对于原子分布的影响,也作了系统的观察。在Ag-Au替换过程中,Au和Ag的替换或多或少是无规律性的,但Zn原子则仍保持它们的适宜位置,而不受到影响。当成分偏离于理想化学式AgAuZn₂时,有序度的减小不仅仅是由于化学成分的乖异,而且Ag-An替换也产生了一些无序的排列。高温观察的结果指出:Ag多合金的β′-β转变温度随着Au含量的增加而升高,而β相只能在高温度存在。少量的Au大大地提高了由淬炼而得到的β′相的稳定度。但是Au多的合金无论是在室温和高温都是具有β′结构的。     

利用红外吸收积分强度进行碳氢化合物中的族分析

本文对于利用红外吸收光谱的积分强度来进行碳氢化合物的族分析作了初步尝试。从分析原子团CH₂及CH₃的结果来看,这方法是可以利用的。     

Synthesis and Characterization of Small Band-gap Conjugated Polymers - Poly(pyrrolyl methines)

A kind of small band-gap conjugated polymers-poly (pyrrolyl methines) and their precursors-(poly pyrrolyl methanes) have been synthesized by a simple method and characterized by 1HNMR, FT-IR, TGA and UV-Vis. These polymers can be dissolved in high polar solvents such as DMSO, DMF or NMP. The results reveals that the band-gap of the synthesized conjugated polymers are in the range of 0.96～1.14 eV and they all belong to the small band-gap polymers. The conductivity of doped products with iodine is in the range of semiconductor.     

PHOTOREACTIONS ASSOCIATED WITH IN VITRO HEMOLYSIS IN ERYTHROPOIETIC PROTOPORPHYRIA*

Abstract— –Photohemolysis of erythrocytes. from patients with erythropoietic protoporphyria results from damage to the cell membrane following photoexcitation of the protoporphyrin molecule by 400 nm radiation. Photochemical reactions were assessed for their roles in initiating cell destruction in an in vitro model in which erythrocytes from patients with erythropoietic protoporphyria were irradiated. Electron transfer properties were demonstrated using 2,3,6-trichloroindophenol as an electron acceptor. Photohemolysis of these abnormal cells is due to cell membrane damage initiating colloid osmotic hemolysis. Additional data are offered demonstrating that this type of photohemolysis is oxygen-dependent, associated with peroxide formation, and preceded by increased osmotic fragility. An hypothesis explaining the interrelationship of the photochemistry of protoporphyrin with the photobiologic observation of hemolysis is offered.     

CONFORMATION AND CHAIN PACKING STRUCTURES OF POLY (ρ-PHENYLEN BENZOBISTHIAZOLE) BY MOLECULAR SIMULATION*

The conformation, the chain packing stabilization and the unit cell modeling of poly(p-phenylene benzobisthiazole) have been investigated by using molecular simulation techniquein the present work. A coupling behaviour of σ-bond rotations at either side of the pheny-lene ring or the heterocyclic ring was found surely to exceed a length of the repeat unit ofthe polymer chain. For a single chain model, the stable torsion angle of the repeat resultedat 14°. In the crystalline cell minimization, the dihedral angle along the polymer chaincould even be stabilized in various values. It therefore indicates that the intermolecularinteraction does play a considerable role for this polymer forming the conformation. Ac-cording to cohesive energies calculated for these unit cell models, the torsion angle in themost stable crystalline cell is 0°. When the chains packing together, there exist so manyenergy stable wells along the chain axis 0.35--0.36nm apart from neighbouring chains.Most of the unit cells have quite closed cohesive energies. These factors thus cause thedifficulty of forming an unique perfect crystalline structure of the polymer. The presentstudy suggested a number of reasonable unit cells, and the most stable crystalline structurefor this polymer that is monoclinic, non-primitive unit cell.     

The Conjugate Gradient Method in Random Variables

We study the conjugate gradient method for solving a system of linear equations with coefficients which are measurable functions and establish the rate of conve...     

Unsteady Simulation of a Jet-in-crossflow

The present work represents the first attempt at studying the unsteadiness of jet-in-crossflows using the Reynolds-Averaged Navier-Stokes (RANS) equations. In the past, numerical studies of jet-in-crossflows, with the exception of the few attempts of DNS and LES. are always carried out under the assumption that the flowfield is steady and symmetric about the jet center plane. Growing experimental evidence suggests that this flow is unsteady and periodic. The present work verified the existence of periodicity in jet-in-crossflows numerically. The numerically predicted Slrouhal number is in good agreement with experimental observations. In addition, the present simulation of the jet-in-crossflow were able to resolve the details of flow structures such as the oscillating wake structures, the jet shear-layer vortices, and the counter-rotating vortex pairs.     

一对普遍的级数变换公式

Very recently, we have found that the method used in our recent paper[1] (appeared in2005) could be extended to obtain two general series-transformation formulas for formal power series defined over the complex number field.     

一对普遍的级数变换公式（英）

利用Krasnoselskii-Zabreiko不动点定理获得了非线性三点边值问题{u″（t）＋a（t）u′（t）＋b（t）u（t）＋h（t）f（t）=0,t∈（0,1） u（0）=0,u（1）=αu（η）解的—个新的存在定理．