UHMWPE／Epoxy冻胶体系的流变行为研究

研究了环氧树脂(Epoxy)加入后对超高分子质量聚乙烯(UHMWPE)稳态表观粘度、粘流活化能以及复数模量和粘度的影响。结果表明,环氧树脂添加量低于1ω,UHMWPE／Epoxy冻胶体系的表观粘度和粘流活化能都低于空白 UHMWPE冻胶体系;当环氧树脂添加量增加至3 ω以后,冻胶体系的表观粘度和粘流活化能均比空白UHMWPE冻胶体系高。     

浸渍增重率和反渗率研究

对浸溃过程中浸渍剂沥青的浸入率和反渗率进行了分析与探讨。提出了理想增重率、理论增重率与实际增重率的概念和计算方法。并比较了实际增重率与操作增重率的差别。同时分析了抽真空的绝对压力与施压的绝对压力对各项增重率和反渗率的影响。     

基于Profibus-DP总线技术的烟支重量控制系统设计

对烟支重量控制系统的控制原理做了较为详尽的描述,介绍了系统硬件组成和软件设计。系统可实时在线对高速烟支重量进行计算,及时准确剔除不合格烟支。通过Profibus-DP总线,烟支重量控制系统实现了与人机界面系统实时、可靠、高速通信,操作人员通过人机界面可以方便的调整控制参数,对设备进行维护。     

基于改进卡方统计的微博特征提取方法

通过对微博文本特征信息的分析与研究,提出一种基于改进卡方统计的微博特征提取方法。扩充微博信息分类特征,在传统的卡方统计量的基础上,引入了频度等因素,改进特征选择方法;在传统的特征项权值计算的基础上,提出了新的改进卡方统计量的方法,改进权重计算效果。对上述方法利用经典KNN和SVM算法进行了测试,实验结果表明该方法提高了微博信息分类的准确率。     

基于区域权函数理论的多电极电磁流量计电极设计

基于Shercliff权函数提出区域权函数概念,设计多电极电磁流量计,通过测量管道截面不同位置的弦端电压,计算各区域的轴向平均速度,实现速度分布与体积流量的测量。着重研究了流量计电极设计,选取不锈钢平头方案的多电极电磁流量计,对于阀门下游的非轴对称单相流体积流量测量精度高于±1.0%,倾斜管固—液两相流实验证明:该设计对于两相流非轴对称的速度分布测量具备可靠性。     

Rheological behaviour of polysaccharide aqueous solutions

Several data relative to the viscosity of water-soluble polysaccharide solutions were collected from the literature and processed by different rheological models. Some relationships between the viscosity of these polymer solutions, their molecular weight and their solution concentrations, were established and their validity checked. Thus, an accurate equation correlating the viscosity and both the shear rate and the solution concentration of different water soluble polysaccharides (xanthan, hyaluronan, carboxymethylcellulose) was deduced on the basis of Cross' model which suggests two domains in which the viscosity is constant, i.e. very low and very high shear rate ranges. Then, an expression relating the zero-shear viscosity (A) and the concentration of their solutions was proposed. Finally, an alternative equation to that of Mark–Houwink correlating the molecular weight and the intrinsic viscosity of the water-soluble polysaccharides studied in this paper was found.     

低密度泡沫玻璃的研究与应用

低密度泡沫玻璃是利用碎玻璃制造的一种气孔率大于90%的隔热保温材料,它具有强度高、导热系数小、吸水率低、不吸湿、耐腐蚀等特性,在潮湿环境下抗冻性能好,是一种优良的低温、超低温隔热保温材料。该产品用途广泛,所用的原材料简单易得,但生产工艺过程比较复杂,生产过程控制精度要求较高,容易产生各种缺陷而影响产品的质量。本文对低密度泡沫玻璃的生产工艺过程进行详细的分析研究,提出相应的措施,确保产品的低密度和高成品率,提高产品的性能,扩大产品的使用范围。     

PVC新型改性剂AS的合成与应用

本文主要介绍ＰＶＣ新型改性剂ＡＳ树脂的合成方法、产品性能及其在ＰＶＣ异型材、管材、注射、压延片等加工领域中的应用。实验结果证明：该产品完全可以代替ＡＣＲ加工助剂，并有很好的经济效益。     

基于鲁棒性的链路权重规划算法

在IP网络中,链路权重规划是流量工程中的重要问题。为了优化网络流量并实现负载均衡,针对业务量矩阵的不确定性,依据鲁棒性理论提出一个链路权重规划的MIP模型。该模型使用Γ模型描述业务量矩阵的不确定集,通过表示扰动程度的参数Γ实现了对鲁棒性的调节,在此基础上求得不确定集中最差情况下的最优解。实验结果表明,与传统的链路权重规划方法以及新出现的MRC规划模型相比较,该算法可降低最大链路利用率,分别达到了40%和20%。     

Cold Crystallization of PLLA Studied by Simultaneous SAXS and WAXS

Summary: The cold crystallization process of initially amorphous poly(L ‐lactic acid), PLLA, with two different molecular weights, during a heating at 2 °C/min, was investigated by DSC and time‐resolved simultaneous SAXS and WAXS, using synchrotron radiation. Equatorial scans of the isotropic 2D‐SAXS patterns showed that the average Bragg long period (L_B) of PLLA samples was approximately constant with the development of cold crystallization up to a temperature that corresponded to a melt/re‐crystallization process that took place before the nominal melting peak seen by DSC. L_B values were found to be higher for the high molecular weight material. This was in accordance with the higher melting temperature observed in the high molecular weight PLLA that implied the existence of thicker lamellae. WAXS results showed that the molecular weight did not apparently affect the crystal form and the final degree of crystallinity of PLLA. The Avrami parameters from WAXS and DSC were consistent, showing that the non‐isothermal cold crystallization of the two PLLA samples corresponded mainly to a three‐dimensional growth, although an imperfect crystallization process was involved at early times. The crystallization rate of PLLA, observed both by WAXS and DSC, decreased with increasing molecular weight.

SAXS profiles of PLLA2 as a function of temperature. The inset shows the 2D‐SAXS pattern obtained at 180 °C.