MECHANICAL-PROPERTIES OF PHENOLPHTHALEIN POLYETHER KETONE - YIELD STRESS, YOUNGS MODULUS, AND FRACTURE-TOUGHNESS

A series of tensile and three-point bending studies was conducted at various temperatures and loading rates using phenolphthalein polyether ketone (PEK-C). Yield stress, Young's modulus, fracture toughness, and crack opening displacement data were obtained for various conditions. In general, both yield stress and Young's modulus increase with decreasing temperature. However, the relationships between fracture toughness, loading rate, and temperature are very complex. This behavior is due to the simultaneous intersection of viscoelasticity and localized plastic deformation. The increased yield stress is the main factor contributing to the reduction in fracture toughness and crack opening displacement. The relationship between fracture toughness and yield stress are discussed. (C) 1995 John Wiley and Sons, Inc.

一种简易型顺磁波谱电化学池的设计和卟啉π-阳离子自由基的检测

设计了一种简易型全玻璃ESR薄层现场波谱电化学池,以高7mm,直径0.5mm的铂柱工作电极安放在直径1mm的玻璃管中,形成体积为4.7μl的薄层池,2ml溶液就可以工作。在二氯乙烷中,进行了薄层电化学性能表征,并对(TPP)H_2的电极氧化过程进行了研究,发现电生的(TPP)H_2阳离子自由基有动力学后行反应。可能的机理是自由基岐化反应伴随着Cl~-引起的异卟啉的生成反应。

Isolation and characterization of microsatellites in yellow perch (Perca flavescens)

A total of 45 microsatellite loci from yellow perch, Perca flavescens, were isolated and characterized. Among the 45 microsatellite loci, 32 had more than two alleles. A wild population of P. flavescens (n = 48) was used to examine the allele range of the microsatellite loci. Mendelian inheritance of alleles was confirmed by examining the amplified products in pair-mated families. The number of alleles for the 32 polymorphic loci varied from two to 16, and observed heterozygosity ranged between 0.024 (YP79) and 0.979 (YP60). Cross-species polymorphic amplification in four other Percidae species was successful for 22 loci.

四川西北地区川西獐牙菜指纹图谱研究（Ⅰ）

目的：建立川西獐牙菜药材甲醇溶解部分的HPLC指纹图谱。方法：反相高效液相色谱法，流动相甲醇．水(水中含0．02％的磷酸)，梯度洗脱，流速1．0mL·min^-1，检测波长260m，柱温30℃。结果：精密度、重复性、稳定性试验中共有峰峰面积、保留时间的RSD均小于5．0％；不同产地川西獐牙菜的相似度大于0．805。结论：该方法简便、实用、可靠，可作为川西獐牙菜药材的质量标准。

赖草属5个种的核型与进化

报道了国产赖草属5 个种的核型, 即大赖草, 2n = 4x = 28= 24m (2SA T ) + 4sm(2SA T) ; 粗穗赖草, 2n= 4x= 28= 22m (2SA T ) + 4sm + 2st (2SA T ) ; 若羌赖草, 2n= 4x= 28=20m (4SA T) + 6sm + 2st (2SA T ) ; 羊草, 2n= 4x= 28= 22m (4SA T ) + 2sm + 4st (4SA T ) ; 窄颖赖草, 2n= 4x= 28= 22m (2SA T) + 4sm (2SA T ) + 2st (2SA T )。同时, 根据Stebbins的核型进化理论和分支系统学的编序赋值方法, 对核型4个重要性状进行了分析, 总结出了5个种的进化指数, 并同外部形态演化分析相印证, 揭示了宏观分类中3个组的系统发育水平。

状态受限的非完整链式系统的实际镇定及其在移动机器人中的应用

本文考虑了状态受限的非完整单链式系统的实际镇定问题.利用链式系统的特殊结构设计了两步控制算法,该方法能够使闭环系统的状态最终收敛到原点的任意小邻域中,且若系统初值小于任意正数(1+ε<,1>)M,那么除了一个收敛到零的状态变量外,其余状态变量在整个实际镇定过程中均小于正数,其中ε<,1>可事先任意小.最后对平面移动机器人进行了仿真,验证了所给方法的有效性.

Methanol steam reforming in a compact plate-fin reformer for fuel-cell systems

A compact plate-fin reformer (PFR) consisting of closely spaced plate-fins, in which endothermic and exothermic reactions take place in alternate chambers, has been studied. In the PFR, which was based on a plate-fin heat exchanger, catalytic combustion of the reforming gas, as a simulation of the fuel cell anode off gas (AOG), supplied the necessary heat for the reforming reaction. One reforming chamber, which was for hydrogen production, was integrated with two vaporization chambers and two combustion chambers to constitute a single unit of PFR. The PFR is very compact, easy to be placed and scaled up. The effect of the ratio of H2O/CH3OH on the performance of the PFR has been investigated, and temperature distributions in different chambers were studied. Besides, the stationary behavior of the PFR was also investigated. Heat transfer of the reformer was enhanced by internal plate-fins as well as by external catalytic combustion, which offer both high methanol conversion ratio and low CO concentration. In addition, the fully integrated reformer exhibited good test stability. Based on the PFR, a scale-up reformer was designed and operated continuously for 1000 h, with high methanol conversion ratio and low CO concentration. (c) 2004 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.

Avaliação preliminar de métodos de enxertia porta-enxertos para a graviola em Rio Branco, Acre.

Este trabalho tem como objetivo avaliar quatro métodos de enxertia e três porta-enxertos para a gravioleira nas condições edafoclimáticas de Rio Branco, AC.

Entrepreneurship and rural economic development: a scenario analysis approach

Fuller-Love, N., Midmore, P., Thomas, D., Henley, A. (2006). Entrepreneurship and rural economic development: A scenario analysis approach. International Journal of Entrepreneurial Behaviour and Research, 12 (5), 289-305. RAE2008

Piecewise Linear Models for the Quasiperiodic Transition to Chaos

We formulate and study analytically and computationally two families of piecewise linear degree one circle maps. These families offer the rare advantage of being non-trivial but essentially solvable models for the phenomenon of mode-locking and the quasi-periodic transition to chaos. For instance, for these families, we obtain complete solutions to several questions still largely unanswered for families of smooth circle maps. Our main results describe (1) the sets of maps in these families having some prescribed rotation interval; (2) the boundaries between zero and positive topological entropy and between zero length and non-zero length rotation interval; and (3) the structure and bifurcations of the attractors in one of these families. We discuss the interpretation of these maps as low-order spline approximations to the classic ``sine-circle'' map and examine more generally the implications of our results for the case of smooth circle maps. We also mention a possible connection to recent experiments on models of a driven Josephson junction.

Herramientas, argumentos y métodos de la modelación lineal

El presente trabajo de investigación forma parte de las actividades que se realizan en el desarrollo del proyecto Laboratorio Virtual de Ciencias como estrategia didáctica para profesores del estado de Guerrero, particularmente de Ayutla de los Libres. Muestra las primeras exploraciones de la puesta en escena con estudiantes de nivel medio superior de diseños de aprendizajes basados en prácticas sociales de modelación de contextos extraescolares. Se muestran las herramientas, argumentos y métodos que emplean los actores al modelar fenómenos lineales creciente, decreciente y constante.