Investigations of Solid State Dynamics at the NRSSR Beamline at PETRA II. An Overview

The present status of the new nuclear resonance beamline PETRA 1 at HASYLAB, DESY, Hamburg is described. Besides an overview of the experimental setup some examples of recent experiments are given. Those cover the main applications, i.e., inelastic scattering from iron alloys and quasielastic scattering from glass-forming liquids. This revised version was published online in August 2006 with corrections to the Cover Date.     

Dielectric effect on the rf characteristics of a helical groove travelling wave tube

A new type of partial-dielectric-loaded helical groove slow-wave structure (SWS) for millimetre wave travelling wave tube (TWT） is presented in this paper.The radio-frequency characteristics including the dispersion properties,the longitudinal electric field distribution and the beam-wave coupling impedance of this structure are analysed.The results show that the dispersion of the helical groove circuit is weakened,the phase velocity is reduced and the position of the maximum Ez is moved from the mouth to the inside of the groove after partially filling the dielectric materials in the helical groove SWS.Therefore,the dielectric-loaded helical groove SWS is suitable for a multi-beam TWT with broad band and high gain.     

Intermittency in the Slow Particle Emission During Hadron–Nucleus Interactions

The study of the angular distribution of slow particles during high energy hadron-nucleus interaction indicates that emission of slow particles takes place from a thermally non-equilibrated system. This evidence has come out from the presence of intermittency - a phenomenon that reveals a fractal structure and represents a self-similarity in the particle production process. Hence, this study highlights inadequacy of cascade-evaporation model and advocates the need of its refinement.     

职校学习后进生的形成原因与教育对策

在职业学校里客观上存在着极少数学习困难、成绩落后的学生，这些学生是教师日常教育教学的重点和难点。本文对学习后进生的形成原因进行比较全面的调查研究，在此基础上采取相应有效的教育对策是成功转化学习后进生的关键。     

Slow crack growth in blends of HDPE and model copolymers

The resistance to slow crack growth (SCG) was measured in binary blends of high density polyethylene (HDPE) and 5–10% concentrations of model ethylene-butene random copolymers by measuring the time to failure (t_f) under a constant stress intensity. An increase of t_f with the addition of the copolymer if the copolymer could crystallize and the increase was greater the higher branch density. The copolymer with 117 branches/1000C could not crystallize and therefore its blend had a t_f that was less than that of the HDPE. The fracture energies of the blends as determined by their resistance to SCG were compared with the energy by rapid fracture, J_c, as previously measured by Rhee and Crist. It is concluded that SCG is more sensitive to variations in the microstructure than is rapid fracture and that the differences in SCG behavior can be qualitatively explained in terms of the differences in microstructure of the blends. ©1995 John Wiley & Sons, Inc.     

聚合物驱蚊剂的慢释放研究

本文研究了丙烯酸酯共聚物载体对驱蚊剂N,N-二乙基间甲苯酰胺(DETA)慢释放行为的控制,探讨了单体配比、共聚物分子量以及DETA含量对释放速率的影响。结果表明。增加亲水性单体丙烯酸(AA),可提高DETA的释放速率;降低共聚物数均分子量,会减少DETA的释放量;剂型中DETA含量与释放量存在线性正比关系,但DETA的含量增加并不导致释放有效时间的线性增加。本文还就共聚物膜的透湿性和碱溶性作了研究,亲水性单体AA的增加同样导致透湿性和碱溶性的增加。制备的聚合物驱蚊剂经现场应用试验,表明具有良好的长效驱蚊特性。     

Effects of BaCl_2 on slow vacuolar ion channels on radish by patch-clamp

Effects of BaCl2 on slow vacuolar ion channels on radish by patch-clamp YANG Pin (杨 频) & ZHANG Liping (张丽平) Institute of Molecular Science, Shanxi University, Taiyuan 030006, China Correspondence should be addressed to Yang Pin (email: yangpin@sxu.edu.cn)     

聚苯乙烯包膜尿素缓释肥的缓释特性研究

以尿素为缓释肥料核心，废聚苯乙烯泡沫塑料作基料，松香为粘结剂，粉煤灰为调理剂。用简易的生产成本研制出较为理想的缓释肥料，为适合目标作物营养需求规律的专用肥奠定工艺基础．采用水溶法对其释放特性进行研究和评价，试验结果表明，缓释效果随着聚苯乙烯浓度、松香量及包膜厚度的增加而提高，但聚苯乙烯浓度超过35％后，因粘度过大给包裹带来困难，从成本考虑松香的加入量为15％左右为佳．     

新型天然橡胶吸油树脂的研制及其性能研究

以天然橡胶生胶为单体．二乙烯苯为交联剂，过氧化蓉甲酰为引发剂，在甲苯溶液中交联聚合得到新型天然橡胶吸油树脂，并对其分子结构进行红外光谱表征。此外探讨了聚合反应条件对树脂吸油率和吸油速率的影响以及树脂的缓释性能。天然橡胶吸油树脂对甲苯的最大吸收率为25．0，对煤油的最大吸收率为26.6。     

动态混合型SMC+Turbo MIMO解调算法

递归蒙特卡洛（Sequential Monte Carlo，SMC）算法是一种有效降低算法复杂度的次优化算法，该算法嵌入到迭代Turbo接收机中可形成低复杂度、高解调性能的SMC＋Turbo MIMO解调接收机．该文针对该解调接收机中的混合型SMC MIMO解调算法，运用动态化参数进行改进．仿真结果表明，动态混合型SMC＋Turbo MIMO解调算法可以在不增加算法复杂度的基础上有效地提高一般混合型方案的性能．