卧螺离心机共直流母线双电机双变频驱动

介绍了卧螺离心机差转速自动控制共直流母线变频调速系统的结构,分析了工作原理和节能效果,介绍了直流母线的两种并接方法。     

A mutational analysis of receptor binding sites of interleukin-1{beta}:differences in binding of human interleukin-1{beta} muteins to human and mouse receptors

The 3-D crystal structure of interleukin-1ß(IL-1ß)has been used to define its receptor binding surface by mutationalanalysis. The surface of IL-1ß was probed by site-directedmutagenesis. A total of 27 different IL-1ß muteinswere constructed, purified and analyzed. Receptor binding measurementson mouse and human cell lines were performed to identify receptoraffinities. IL-1ß muteins with modified receptor affinitywere evaluated for structural integrity by CD spectroscopy orX-ray crystallography. Changes in six surface loops, as wellas in the C- and N-termini, yielded muteins with lower bindingaffinities. Two muteins with intact binding affinities showed10- to 100-fold reduced biological activity. The surface regioninvolved in receptor binding constitutes a discontinuous areaof 1000 Å2 formed by discontinuous polypeptide chain stretches.Based on these results, a subdivision into two distinct localareas is proposed. Differences in receptor binding affinitiesfor human and mouse receptors have been observed for some muteins,but not for wild-type IL-1ß. This is the first timea difference in binding affinity of IL-1ß muteinsto human and mouse receptors has been demonstrated     

注塑产品色差控制技术研究

色差是注塑中最常见缺陷，因其牵涉因素众多，十分难以掌握。本文从实用角度出发，讨论了影响色差主要因素和控制色差的实用技术．为减少色差问题的产生提供了一些好的经验和方法。     

Shear-rate dependence of first normal stress difference of poly(isoprene-b-styrene) in solution near the order-disorder transition temperature

Viscoelastic properties of poly(isoprene-b-styrene) in dioctylphthalate under steady shear flow were measured near the order—disorder transition temperature. In ordered states, first normal stress difference N₁ is proportional to shear rate at low region, but becomes proportional to at the high region, similar to the N₁ behaviour of polymer blends undergoing shear-induced homogenization. Because the existence of microdomains was confirmed at the high region by the flow birefringence method, it is concluded that the above N₁ behaviour is not caused by shear-induced homogenization, but is probably caused by the shear-induced alignment of the microdomain structure.     

分散染料在涤/锦双组分纤维上色差的色度学分析

将涤 /锦复合丝分离成单一组分的超细涤纶和锦纶。用常用的分散染料同浴染色后 ,测定了各染色样品的颜色三刺激值 ,并经过色度学计算。实验分析表明 ,分散染料对锦纶染色物的反射光主波长值较相应涤纶染色物向长波方向移动 ;蒽醌类分散染料在锦纶上的得色量较小 ,彩度较低 ;而偶氮类分散染料对涤 /锦染色的总色差较小 ,较适合于涤 /锦复合丝的染色。     

从英汉习语看中西文化差异

习语是某一语言在使用过程中形成的独特的固定的表达方式.通过研究英语和汉语中的成语、习语的语言特点,分析了两种语言在文化上面的差异及影响差异的因素,包括自然环境、生产活动、历史传统等.因此在跨文化交际和翻译实践中要重视文化差异,实现两种语言的文化对等.     

三站匀扫波束时差定位及测量误差

该文针对仅由时差测量所得到的波束扫描角,并利用平面三角函数关系,即能直接在极坐标系中导出非直线不等间距三站阵列对匀速扫描雷达站的定位公式。应用误差估计理论所做的分析显示,基于匀速波束扫描时差测量的三站无源定位系统具有较高的测向精度,且在基线方向不存有测向盲区。采用非直线、不等距布阵亦能进一步有效降低测向误差。如V形布阵,则在阵列夹角的中心线上具有最小误差值。同时,误差分析亦表明,目前所给出的距离公式的测量误差还是较大的。     

隧道窑预热带烟气流动对上下温差的影响

为减小隧道窑预热带上下温差,利用计算机数值模拟对预热带温度场进行研究,找出烟气流动对隧道窑预热带上下温差的影响规律.在预热带内来流烟气的温度保持不变,速度为0.5～1.0 m/s时,窑内温度均匀性较好.在保持来流烟气温度和速度不变的情况下,码料密度的合适值为孔隙率在0.208～0.408范围内,可提高产品的质量和产量.     

一类高阶非线性差分方程的吸引性

在文献[1-2]的基础上,研究了非线性差分方程xn+1=a-bxpn-k/A-x2n的全局稳定性和正解的周期性,其中a,A为非负实数,b为正实数,k,p∈{1,2,…},p≥2.证明了该方程的一个正平衡点是一个全局吸引子,并给出了相应的吸引域.     

一类非线性时滞偏差分方程的不饱和解

利用频密测度和无穷双序列{um,n}不饱和解的概念,讨论了一类带有可变号系数的非线性时滞偏差分方程解的不饱和性质,给出了偏差分方程解的频密振动性的几个充分条件.