A new method for producing high melt strength polypropylene with reactive extrusion

A high‐melt‐strength polypropylene (HMSPP) was prepared using a twin‐screw reactive extruder from a commercial isotactic polypropylene through two stages, first, maleic anhydride is grafted to polypropylene to obtain a maleic anhydride‐grafted polypropylene (PP‐g‐MA), and then the grafted polymer is reacted with epoxy to extend the branched chain. Fourier transformed infrared spectroscopy indicated that maleic anhydride was grafted on polypropylene and reacted with epoxy. Melt flow rate and sag resistance test showed that the melt strength of the HMSPP improved considerably. Differential scanning calorimetry test showed that the long chain branches (LCBs) act as a nucleating agent in the crystallization of the HMSPP, which leads to a high crystallization temperature and crystallinity. Furthermore, the LCB efficiency of the HMSPP can also be calculated by analyzing its rheological property. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

赴日无线电监测技术考察报告

首先介绍了日本总务省关东综合通信局电波监理部的情况，然后对日本安立公司生产的RR510A型无线电监测接收机和技术参数以及MS8609A型数字移动无线发射机测试仪的功能进行了分析和介绍。     

On a three-dimensional axisymmetric boundary-value problem of nonlinear elastic deformation: Asymptotic solution and exponentially small error

In this paper, we study a three-dimensional axisymmetric boundary-value problem of a slender cylinder composed of a nonlinearly elastic material subjected to an axial force. Starting from the field equations, after a transformation and proper scalings, we identify a small variable and two small parameters, which characterize the present problem. Then, by an approach involving compound series-asymptotic expansions, a nonlinear ODE is derived, which governs the axial strain (the first-term in the series expansion). By imposing the zero radial displacement conditions at two ends, we manage to get the analytical solution of the axial strain, from which all other physical quantities can be deduced and thus the three-dimensional displacement field can be determined. Graphical results are presented, which show that there are two boundary layers near the two ends while the middle part is in a state of almost uniform extension. The asymptotic structure of the analytical solution is derived, which offers clear explanations to the structure of the deformed configuration and shows that the thickness of both boundary layers is of the order of the radius. We also point out the relevance of the present results to the St. Venant’s problem. In particular, we obtain the explicit uniformly-valid exponentially small error term, when the obtained deformed configuration is compared to the configuration of a uniform extension.     

The changes of lipid metabolism and hemorrheology in intrahepatic cholestasis during pregnancy

OBJECTIVE: To identify the influence of the increased level of serum cholyglycine (CG) on lipid metabolism and hemorrheology in patients with intrahepatic cholestasis during pregnancy (ICP). METHODS: The concentrations of serum CG, total cholesterol (CH), triglycerides (TG), high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), high shear and low shear of blood specific viscosity (HS and LS), plasma specific viscosity (PV) and hematocrit (HCT) were measured in 68 cases of primiparas with single pregnancy and 30 healthy nonpregnant women respectively. The group of ICP was composed of 35 cases with CG > 6 mumol/L, the group of normal pregnancy, 33 cases with CG < 6 mumol/L. RESULTS: The means of CG and the lipidic parameters in the two pregnant groups were significantly higher than those in the non-pregnancy group (P < 0.02-0.001) except the means of HDL-C between the groups of ICP and non-pregnancy. The levels of LDL-C, LDL-C/HDL-C, LS, PV and HCT in the ICP were significantly higher than those in the normal pregnancy group (P < 0.02-0.001). CONCLUSIONS: There are significant changes of lipid metabolism and hemorrheology in patients with ICP. However, these changes could be corrected after pregnancy termination, when the level of serum CG returned to normal. The results suggest that the pathophysiologic changes of ICP are associated with increased level of serum CG.     

硬件握手双向选通型串行通信共享器的设计

本文介绍了ＩＢＭ－ＰＣ系列计算机通过ＲＳ－２３２Ｃ串行口与多个单片微机组成的分布式系统中一种可双向选通串行通信共享器的设计方法。给出通信共享器的设计电路；并对电路工作原理进行了详细剖析。     

噪声测量作为筛选光电耦合器件的一种方法

本文针对目前用于光电耦合器件筛选方法的不足，提出了用测量耦合器件噪声功率谱的方法来筛选掉噪声值大的器件，给出一批光电耦合器件的测量统计结果及在不同工作点时的噪声功率谱，并给出相应的筛选标准，实验结果表明，这种方法是有效、可行的。     

珠江口盆地开平凹陷油气聚集条件分析

珠江口盆地自新生代以来,曾先后受到不同方向张应力的作用,造成了不同时期构造体系的交叉叠合.中中新世以来构造运动强烈,并具有东强西弱的特点,对油气的运移与聚集产生了重要影响.开平凹陷的剧烈断裂和断陷活动始于始新世,并在同期沉积了巨厚的文昌组.晚渐新世以后,由于断裂活动非常微弱,在成熟的烃源岩与其上地层之间缺乏有效的油源断层,因而自生自储、近距离运移可能是开平凹陷油气聚集的基本特征.在凹陷内部,因重力滑动和欠压实泥岩共同作用所形成的KPll-1构造带可能是该区最具有油气远景的地区.     

电离层时域探测方法

给出了各向同性分层半空间等离子体对时域电磁脉冲后向散射的有关公式，得出了反抛物层时域响应的解析表达式，并利用时频分析方法演出了电子密度分布。     

Implementation of secure digital communication by hyperchaoticsynchronisation

By active-passive-decomposition synchronisation, the application of the one-way coupled ring map lattice hyperchaotic system in secure digital speech communication is demonstrated. Synchronisation guarantees strong security and recovery without error     

光纤压力传感器微机控制与数据处理系统

本文介绍的光纤压力传感器微机控制与数据处理系统是以8098单片机为核心,配上适量的外围电路所构成。该系统直接利用8098单片机芯片内的A/D模拟输入通道和脉宽调制(PWM)功能来进行数据采集和输出控制信号。该系统还方便地实现与微型打印机的联接,以便将采集的数据保存。整个系统结构简单,成本低,可靠性高,实时控制和测试功能较强,有良好的工业应用价值。