Compatibility and specific interactions in poly(beta-hydroxybutyrate) and poly(p-vinylphenol) blends

The miscibility and specific interactions in poly (beta-hydroxybutyrate) (PHB)/poly(p-vinylphenol) (PVPh) blends were studied by differential scanning calorimetry(DSC) , fourier transform infrared(FTIR) spectrometer and high resolution solid state C-13 NMR, A single composition-dependent glass transition temperatures were obtained by DSC which indicate the blends of PHB/PVPh were miscible in the melt state, The experimental glass transition temperatures were fitted quite well with those obtained from Couchman-Karasz equation. The FTIR study shows that the strong intermolecular hydrogen bonding exists in blends of PHB with strong proton acceptor and PVPh with strong proton donor and is the origin of its compatibility. The CPMAS C-13 NMR spectra also show that the strong hydrogen bonding exists in PHB/PVPh blends. From the T-1 rho(H) relaxation time it follows that the blends of PHB/PVPh(40/60, 20/80) studied are completely homogeneous on the scale of about 3.2 nm.

PHB／PVPh共混体系的相容性及分子间的特殊相互作用

ＰＨＢ／ＰＶＰｈ共混体系的相容性及分子间的特殊相互作用邢佩祥，董丽松，冯汉桥，安玉贤，庄宇钢，冯之榴（中国科学院长春应用化学研究所高分子物理开放实验室，长春，１３００２２；中国科学院武汉物理研究所波谱与原子分子实验室）关键词氢键，相容性，聚（β－羟基...

Effects of body size and water temperature on food consumption and growth in the sea cucumber Apostichopus japonicus (Selenka) with special reference to aestivation

To investigate the effects of body size and water temperature on feeding and growth in the sea cucumber Apostichopus japonicus (Selenka), the maximum rate of food consumption in terms of energy (C-maxe; J day(-1)) and the specific growth rate in terms of energy (SGRe; % day(-1)) in animals of three body sizes (mean +/- SE) - large (134.0 +/- 3.5 g), medium (73.6 +/- 2.2 g) and small (36.5 +/- 1.2 g) - were determined at water temperatures of 10, 15, 20, 25 and 30 degrees C. Maximum rate of food consumption in terms of energy increased and SGRe decreased with increasing body weight at 10, 15 and 20 degrees C. This trend, however, was not apparent at 25 and 30 degrees C, which could be influenced by aestivation. High water temperatures (above 20 degrees C) were disadvantageous to feeding and growth of this animal; SGRe of A. japonicus during aestivation was negative. The optimum temperatures for food consumption and for growth were similar and were between 14 and 15 degrees C, and body size seemed to have a slight effect on the optimal temperature for food consumption or growth. Because aestivation of A. japonicus was temperature dependent, the present paper also documented the threshold temperatures to aestivation as indicated by feeding cessation. Deduced from daily food consumption of individuals, the threshold temperature to aestivation for large and medium animals (73.3-139.3 g) was 24.5-25.5 degrees C, while that for small animals (28.9-40.7 g) was between 25.5 and 30.5 degrees C. These values are higher than previous reports; differences in sign of aestivation, experimental condition and dwelling district of test animals could be the reasons.

柔性制造单元一种多层计划调度方法

柔性制造单元的计划与调度问题已有许多的讨论,但大都针对具体的系统以及对任务做某些假设,本文提出一种多层计划和调度的方法并对每层的功能进行讨论,这种方法的结构可应用于各类单元.同时提出三种机器资源的分配方法.文中给出了仿真结果表明此方法是比较有效的.

贵阳市市西河最小生态环境水量初步研究

针对整治后市西河河流系统的特点及主要生态环境服务功能目标,从水质功能达标、保护水生生物栖息地、景观娱乐用水三个角度,计算出市西河的各类生态环境水量,取其所需临界流量中最大的一个作为市西河河流生态环境水量。研究表明,市西河最小生态环境水量应为2. 376 m3/ s ,大于二桥断面河流实际水量0. 914 m3/ s ,必须通过调水或其它方式解决。