管道纺纱装置结构的优化

本文对管道纺纱装置的结构进行了深入的研究,提出了在原管道纺纱装置的基础上,将吸风装置绕输纤管道的轴线旋转180°的新方案。以这个设计方案为基础,对其主要的结构参数和主要的工艺参数进行了优化,求得了最佳结构参数和最佳工艺参数。再根据最佳结构参数制造有关零件,装在管道纺纱单头试验机上,以求得的最佳工艺参数为工艺务件,实际纺制28tex 纯棉纱。这个新装置不仅能稳定地纺纱,而且其成纱的缕纱强力与优化计算的结果基本一致。     

广告翻译——选择与顺应

作为实用翻译的一种,广告翻译的功利性决定了其翻译不可能是简单机械地重现原文,更不能死守传统的所谓“忠实”的翻译观。为了适应商业社会激烈的竞争,本文根据J．Verschueren的语言顺应理论提出:广告翻译是一个通过不断选择来顺应目的语的语言和文化,从而成功完成广告翻译的任务,达到广告目的的一个过程。同时指出应该在哪些方面作出顺应。     

新型垂直沟道的NPN型偶载场效应晶体管的设计及特性

研制了一种新模式的半导体场效应晶体第－－垂直沟道的偶载场效应晶体管（VDCFET），这种结构可以避免现有光刻技术的制约，使用常规的半导体双极晶体管工艺，既可把有效沟道长度减短，大大提高器件的速度，又可将电源电压降低到小于1V，大幅度降低功耗，改进其电学性能。本器件可应用于高频电路、D触发器、环振电路及反相器等重要电路。从纵向和横向报道了器件的设计思想，并给出了器件特性的测量结果。     

The effects of manganese and barium on the cardiac pacemaker current,i f,in rabbit sino-atrial node myocytes

Summary The isolation of ionic fluxes contributing to electric currents through cell membranes often requires block of other undesired components which can be achieved, among others, by divalent cations. Mn²⁺ and Ba²⁺ are often used, for example, to block Ca and K currents. Here we have investigated the effects of these two cations on the properties of the hyperpolarization-activated pacemaker current i_f, in rabbit sino-atrial node myocytes, as obtained by voltage clamp analysis. We find that 2 mM Mn²⁺ shifts the i_f activation curve by 3.2±0.3 mV towards more positive values. However, when 1 mM Ba²⁺ is also added, the positive shift is more than halved (1.3±0.2 mV). We find, too, that in the absence of blocking cations the ACh-induced i_f inhibition is slightly higher than in their presence. These results indicate that the alteration of i_f kinetic properties by Ba²⁺ plus Mn²⁺-containing solutions is minimal.     

沟道粒子的非线性过程

从经典的角度,采用双势井模型与余弦势模型,研究了沟道中粒子的经典运动及其俘获态与非俘获态;从量子的角度,研究了沟道中粒子波函数的传播.所得结果与用Lindhard势及Mo-liere势的结果一致.     

Permeation study of the potassium channel from streptomyces Lividans

A three-state hopping model is established according to experiments to study permeation of an open-state potassium channel from Streptomyces Lividans (KcsA potassium channel). The master equations are used to characterize the dynamics of the system. In this model, ion conduction involves transitions of three states, with one three-ion state and two two-ion states in the selectivity filter respectively. In equilibrium, the well-known Nernst equation is deduced. It is further shown that the current follows Michaelis-Menten kinetics in steady state. According to the parameters provided by Nelson, the current-voltage relationship is proved to be ohmic and the current-concentration relationship is also obtained reasonably. Additional validation of the model in the characteristic time to reach the steady state for the potassium channel is also discussed. This model lays a possible physical basis for the permeation of ion channel, and opens an avenue for further research.     

Identification of swelling-activated Cl<Superscript>-</Superscript> current in rabbit cardiac Purkinje cells

The presence and functional role of the swelling-activated Cl^- current (I_Cl(swell)) in rabbit cardiac Purkinje cells was examined using patch-clamp methodology. Extracellular hypotonicity (210 or 135 mOsm) activated an outwardly rectifying, time-independent current with a reversal potential close to the calculated Cl^- equilibrium potential (E_Cl). The magnitude of this current was related to tonicity of the superfusate. The current was blocked by 0.5 mM 4,4-diisothiocyanostilbene-2,2-disulfonic acid (DIDS). These features are comparable to those of I_Cl(swell) found in sinoatrial nodal, atrial, and ventricular myocytes. I_Cl(swell) activation at 210 and 135 mOsm depolarized the resting membrane potential with 6 and 10 mV and shortened the action potential by 18 and 33%, respectively. DIDS partially reversed I_Cl(swell)-induced action potential changes. We conclude that I_Cl(swell) is present in Purkinje cells and its activation leads to action potential shortening and resting membrane potential depolarization, both of which can promote the development of reentrant arrhythmias.Received 20 January 2004; received after revision 17 February 2004; accepted 25 February 2004     

移动通信Rician信道中的多普勒影响分析

在研究分析了陆地移动通信Rician多径信道中因存在较强支配路径信号入射以及入射路径空间位置发生变化对Doppler频谱密度所产生影响的基础上 ,指出在实际无线传播环境中的一般性Doppler频谱密度通常应为非对称的 ,并且给出了相应的理论分析和仿真结果     

Photoshop中不规则图像的选取方式

运用Photoshop软件处理图像时,“选取”是首要的也是至关重要的五。本文根据艺术设计实际运用情况,对于选取的方法进行了多方面的探索和总结。     

计算网格中的组件服务

在网格环境下的高能计算中,网络应用扩展为一系列的相互作用的组件,一个完整的网络应用应该以即插即用的方式整合这些组件.文中采用了公共组件结构来建立这些组件.为了提高组件之间的通信效率,增加组件的动态扩展性,还需要事件服务以及通道的概念.本文中还用到了一些XML的内容.