Mechanical properties of amphiphilic urethane acrylate ionomer hydrogels having heterophasic gel structure

Amphiphilic urethane acryale hydrogels containing ionic groups (dimethylolpropionic acid) were prepared by varying the molecular weight of the soft segment (polyether type) and the type of diisocyanate, and their mechanical properties were examined. They showed heterophasic gel structure composed of ionic hard domains induced by aggregation of the ionic groups and polyether soft domains comprising the urethane acrylate network. This heterophasic structure could be confirmed by dynamic mechanical analysis (DMA) and by wide-angle X-ray scattering analysis (WAXS); the crystallinity detected by WAXS and the transition peak of the ionic hard domains detected by DMA strongly suggested that there were ionic aggregates. These ionic aggregates acted as reinforcing fillers in the network, which eventually enhanced the tensile strength of the hydrogels. Above all, the tensile properties of the hydrogels were of interest in that the trends of the stress-strain curves were consistent with the rubbery ones. It is believed that the higher purity of the polyether soft domains resulted from the heterophasic gel structure imparting further elastomeric properties on the network. Received: 31 July 1998 Accepted in revised form: 15 October 1998     

Study of sawtooth oscillations on the HT-7 tokamak using 2D tomography of soft x-ray signal

It is the first time so far as we know that two arrays of multi-channel soft x-ray detectors are used to generate twodimensional （2D） images of sawtooth oscillation on the HT-7 tokamak using the Fourier-Bessel harmonic reconstruction method, and using the singular value decomposition to analyse the data from soft x-ray cameras. By these two arrays, 2D image reconstruction of soft x-ray emissivity can be obtained without assumption of plasma rigid rotation. Tomographic reconstruction of the m=1 mode structure is obtained during the precursor oscillation of the sawtooth crash. The crescent-shaped mode structure appearing on the contour map of the soft x-ray emissivity is consistent with the quasiinterchange mode. The characteristics of the m=1/n=1 mode structure observed in the soft x-ray tomography are as follows： the magnetic surface is made up of the crescent-shaped “hot core” and the circular “cold bubble”. The structure of the magnetic surface rotates in the direction of the electron diamagnetic drift and the rotation frequency is the oscillation frequency of soft x-ray signals.     

双狭缝透射光栅软X光时空分辨谱仪

 利用双狭缝、透射光栅配亚仟X光条纹相机做了具有一维空间、时间和能谱分辨的三维软X光测量仪器(双狭缝透射光栅软X光时空分辨谱仪), 并成功地获得了金盘靶的N带X光(中心波长1.7nm)时空分辨图象 。该仪器空间分辨可达23μm, 时间分辨可达003ns, 能谱分辨(当源大小为100～300μm时对波长1.7nm的X光)可达0.4～ 0.7nm, 只需稍加改动, 即可用于其它波段的X光测量。     

Bankruptcy prediction in banks and firms via statistical and intelligent techniques – A review

This paper presents a comprehensive review of the work done, during the 1968–2005, in the application of statistical and intelligent techniques to solve the bankruptcy prediction problem faced by banks and firms. The review is categorized by taking the type of technique applied to solve this problem as an important dimension. Accordingly, the papers are grouped in the following families of techniques: (i) statistical techniques, (ii) neural networks, (iii) case-based reasoning, (iv) decision trees, (iv) operational research, (v) evolutionary approaches, (vi) rough set based techniques, (vii) other techniques subsuming fuzzy logic, support vector machine and isotonic separation and (viii) soft computing subsuming seamless hybridization of all the above-mentioned techniques. Of particular significance is that in each paper, the review highlights the source of data sets, financial ratios used, country of origin, time line of study and the comparative performance of techniques in terms of prediction accuracy wherever available. The review also lists some important directions for future research.     

脉冲软X光辐射三种材料的喷射冲量实验研究

 在强光一号脉冲加速器上进行了国内首次的实验室软X光辐射三种材料的喷射冲量研究。结果表明，在能量为(0.2～0.33)keV、平均脉宽为39ns左右的X光辐射下，对灰漆、白漆和硬铝，在能注量分别为(92～152)J/cm²、(115～136)J/cm²和(163～192)J/cm²时，它们的冲量耦合系数分别为(0.61～0.80)Pa·s/(J·cm^-2)、(0.58～0.97)Pa·s/(J·cm^-2)和(0.61～0.84)Pa·s/(J·cm^-2)。     

Some Problems on Reconstruction of Soft X -ray Hologram with Visible Light

ＳｏｍｅＰｒｏｂｌｅｍｓｏｎＲｅｃｏｎｓｔｒｕｃｔｉｏｎｏｆＳｏｆｔＸ－ｒａｙＨｏｌｏｇｒａｍｗｉｔｈＶｉｓｉｂｌｅＬｉｇｈｔ￥ＣＨＥＮＪｉａｎｗｅｎ；ＸＵＺｈｉｚｈａｎ；ＺＨＵＰｅｉｐｉｎｇ；ＸＩＡＯＴｉｑｉａｏ；ＫＯＵＬｅｉｇａｎｇ；ＷＡＮＧＺｈ...     

钙钛矿结构中的简谐子软模

利用复合空间型方法,在自由边界条件下解出了钙钛矿结构有限尺寸晶体的简谐振动方程.计算结果给出了收敛的简谐子谱分布,并发现了许多简谐子软模.用这些软模花样说明了钛酸钡晶体冷却时发生具有a畴和c畴结构的铁电相变.理论表明铁电相变过程涉及屏蔽电荷的激发及其在界面的缓慢扩散,以最后得出各个电畴内部的均匀自发极化 关键词： 晶格动力学 简谐子 软模 钛酸钡     

软代数的Stone定理

对于每一个正规软代数Ｆ，对应有一个准Ｂｏｏｌｅ环Ｆ．反之，每一个准Ｂｏｏｌｅ环Ｒ，对应有一个正规软代数Ｒ，且有＝Ｆ，＝Ｒ．