直接凝固注模成型Si_3N_4及SiC陶瓷──基本原理及工艺过程

直接凝固注模成型（ｄｉｒｅｃｔｃｏａｇｕｌａｔｉｏｎｃａｓｔｉｎｇ，ＤＣＣ）是一种崭新的（准）净尺寸陶瓷成型方法。本文报道了采用此法成型Ｓｉ_３Ｎ_４及ＳｉＣ陶瓷的基本原理和工艺过程。ＤＣＣ成型工艺过程为把高固相含量低粘度的陶瓷浆料浇注到无孔模具中，事先加入到浆料中的生物酶及化学物质通过改变浆料的ｐＨ或电解质浓度来改变浆料的胶体化学行为，从而使浆料原位凝固，得到有足够脱模强度的陶瓷坯体。ＤＣＣ成型的特点为坯体密度高（理论密度的５５％～７０％），坯体均匀，不用或只需少量的有机添加剂（少于１％），可成型大尺寸、复杂形状、高可靠性的陶瓷部件。     

基因及凝固注模成型Si3N4及SiC陶瓷：基本原理及工艺过程

直接凝固注模成型（ｄｉｒｅｃｔ ｃｏａｇｕｌａｔｉｏｎ ｃａｓｔｉｎｇ，ＤＣＣ）是一种崭新的（准）净尺寸陶瓷成型方法。本文了采用此法成ｉ３Ｎ４及ＳｉＣ陶瓷的基本原理和工艺过程，ＤＣＣ成型工艺过程为把高固相含量低粘度的陶瓷浆料浇注到无孔模具中，事先加入到浆料中的生物酶及化学物质通过改变浆料的ＰＨ或电解质浓度醚改变浆料的胶体化学行为，从而使浆料原位凝固，得到有足够脱模强陶瓷坯体。ＤＣＣ成型的特点为坯体     

RTM成型用CDR—9418的工艺性研究

本文介绍了ＲＴＭ成型用低粘度双马来酰亚胺基体树脂ＣＤＲ－９４１８的合成，及该树脂的成型加工工艺。     

浅述BMC注射成型技术

介绍ＢＭＣ注射成型技术的特点与原理，讨论了ＢＭＣ注射成型设备的性能特点及工艺条件，并分析了ＢＭＣ注射制件常见的缺陷及其原因等。     

陶瓷注射成型有机载体的选择及相容性研究

对数种陶瓷注射成型常用的有机载体，通过ＤＳＣ，ＳＥＭ，溶度参数计算和高温金相显微镜观察，定性和定量地研究了有机载体之间的相容性及它们与Ｓｉ３Ｎ４粉体的润湿性，在此基础上的考察了配方不同的注射成型混合物料的流变特性，确定了适于陶瓷注射成型的有机载体。     

蓄电池盒也成型模流分析

本文利用美国ＡＣＴ公司开发的Ｃ－ＭＯＬＤ软件，对蓄电池盒射出成型进行模拟，用以解决该塑件充模不平衡拨模等缺陷。该塑件属单模穴，多点浇口模具，制件有五个隔板、薄壁、深腔，且壁厚是变化的。利用Ｃ－ＭＯＬＤ软件对其进行确定出最佳的浇口位置、数目及尺寸，并为用户有提供最佳的工艺方案。     

挂衣巾和RPVC椭圆管生产技术

利用ＫＭＤ－６ＫＫ锥形双螺杆挤出机和ＲＰＶＣ管材挤出口芯模生产ＲＰＶＣ椭圆管时,必须在定径套与口芯模之间套接一个至关重要的过渡装置,否则难以挤出成型。本文主要介绍该过渡装置及定径套的设计、ＲＰＶＣ椭圆管的配方选择及成型工艺控制。     

用DMC制德倍捻机压轮

了用ＤＭＣ生产压轮的成型工艺，得到了符合使用要求的产品。     

涂层转移法精密铸造技术在子午线轮胎模具制造中的应用

子午线轮胎模具计算机辅助快速制造系统是由ＣＡＤ技术、快速成型技术、涂层转移法精密铸造技术、材料技术等多项高新技术组合而成的一项独特的先进制造技术。该系统充分利用液态材料成型任意性和高再现性的特点，具有适应性强、重复性好、加工周期短、制造成本低的特点。     

增强反应注射成型聚氨酯及其性能研究

以反应注射成型聚氨酯（ＲＩＭ－ＰＵ）为基体树脂，研制了以玻纤增强剂的增强反应注射成型聚氨酯（ＲＲＩＭ－ＰＵ）材料。讨论了原材料及玻纤对ＲＲＩＭ－ＰＵ加工工艺及材料性能的影响。结果表明，以碳化二亚胺改性的异氰酸酯（ＣＭ－ＭＤＩ）和低聚合异氰酸酯改性的异氰酸酯（ＰＡＰＩ）混合物与丙腈－－苯乙烯接枝改性环氧乙烷封端的聚醚二元醇（ＡＰＧ）为主要原料，玻纤长度不大于１．５时，不仅ＲＲＩＭ加工工艺性好，而且Ｒ     

陶瓷直接凝固注模成型（DCC）原理及应用

直接凝固注模成型是一种崭新的净尺寸陶瓷成型概念，其基本过程是通过酶催化底物的化学反应改变，ｐＨ值至等电点（ＩＥＰ）或增加盐离子浓度，使双电层稳定的陶瓷浓悬浮体实现原位凝固，得到均匀，无密度梯度的坯体，然后干燥（无需脱脂）烧结致密化，本文详细讨论了这种成型工艺的原理和应用研究成果。     

射流稀疏颗粒图像PIV算法应用

颗粒图像测速（particle image velocimetry,简称PIV）是一种非接触式流场测量方法,它具有全场以及对流场无干扰的特点,在流体力学、化工等很多领域均有非常广泛的应用．     

Degradable cationic clarifiers based on ester bonds for treating wastewater produced from polymer flooding

Polymer-contained oily sludge is inevitably produced when the oily wastewater produced from polymer flooding (OWPF) is treated by a cationic polymer clarifier, and it severely affects oilfield production. This study designed a novel degradable cationic clarifier (DCC) based on the ester bond and prepared it in light of the poly(β-amino ester) used in the area of generic material delivery. First, the copolymer of N-[3-(dimethylamino) propyl] methacryamide (DMAPMA) and diallylamine (PDMAPMA-NH) were synthesized by radical copolymerization. Then, the DCC was prepared by Michael addition between PDMAPMA-NH and poly(ethylene glycol) diacrylate. The synthesis conditions of DCC were investigated, and a DCC with excellent flocculant performance and good degradability was successfully prepared. At 70°C, both the degradations of DCC and the water-insoluble polymer complex formed by DCC and the polymer used for polymer flooding can be completed in 10 h, which is beneficial for the self-disappearance of the polymer-contained oily sludge. The flocs formed by DCC were observed at different times, and the results confirmed that the flocs can change to an oil film and that the polymer-contained oily sludge cannot exist for a long time. This study provides inspiration for OWPF treatment and expands the new application for poly(β-amino ester).     

Thiol esters of 2-mercaptoethanol and 3-mercapto-1,2-propanediol

2-Mercaptoethanol and 3-mercapto-1,2-propanediol are selectively S-acylated by fatty acids with dicyclohexylcarbodiimide (DCC) catalyzed by 4-dimethylaminopyridine. Since reaction of such thiols with acid halides produces mixtures of S- and O-acylated materials, the procedure using DCC is more efficient. Such thiol esters are valuable as substrates in the study of lipase activity, using Ellman's Reagent in a continuous spectrophotometric assay. This selective synthesis will facilitate the study of fatty acid residues that are less available. Rearrangement of S- to O-acylated compounds occurs only slowly under the conditions of the lipase assay and should not significantly affect activity measurements. Using DCC, it is possible to sequentially esterify 2-mercaptoethanol to form unsymmetrical diesters.     

新产品DCC的开发现状

为避免版权之争,改进现有的音频系统,飞利浦公司于1989年研制成功采用数字音频技术的第一台DCC样机,此后,DCC盒带迅速发展。文中介绍了DCC机的原理和特点、DCC盒带的性能和特点及DCC系统的技术指标。     

A new direct coagulation casting process for alumina slurries prepared using poly(acrylate) dispersant

Direct coagulation casting (DCC) of concentrated aqueous alumina slurries prepared using ammonium poly(acrylate) dispersant has been studied using MgO as coagulating agent. Addition of small amounts of MgO increased the viscosity of the concentrated alumina slurries with time and finally transformed it in to a stiff gel. Sufficient working time for degassing and casting could be achieved by cooling the slurries to a temperature of ∼5 °C after proper homogenization after the addition of MgO. The DCC slip with alumina loading in the range of 50–55 vol% showed relatively low viscosity (0.12–0.36 Pa s at shear rate of 93 s⁻¹) and yield stress (1.96–10.56 Pa) values. The wet coagulated bodies prepared from slurries of alumina loading in the range of 50–55 vol% had enough compressive strength (45–211 kPa) for handling during mould removal and further drying. The coagulated bodies prepared from slurries of alumina loading in the range of 50–55 vol% showed linear shrinkage in the range of 4.8–2.3 during drying and 17.1–16.2 during sintering respectively. Near-net-shape alumina components with density >98% TD could be prepared by the DCC process.     

Magnesia induced coagulation of aqueous PZT powder suspensions for direct coagulation casting

Coagulation characteristics of poly(acrylate) dispersed PZT powder suspensions by MgO coagulating agent have been studied. The PZT powder suspensions undergoes coagulation at MgO concentrations much lower than the equivalent amount to react with the dispersant indicating a major shift in the coagulation mechanism from the corresponding alumina powder suspensions. Unlike in alumina powder suspensions, the Mg²⁺ ions generated from the MgO reacts with the ammonium poly(acrylate) adsorbed on particle surface that result in cross-linking of PZT particles by Mg²⁺ through the ammonium poly(acrylate) molecules. The particle bridging induces faster coagulation of the slurry cast in a mould as required for an ideal DCC process. The compressive strength and stability against oscillatory stresses of the wet-coagulated bodies increased with increase in number of cross-links between the particles. The PZT green bodies prepared by the DCC process sintered to near theoretical density and the MgO added as coagulating agent (～0.1 wt%) had only minor influence on its piezoelectric characteristics.     

陶瓷成型新方法及其应用的研究

介绍和讨论了作为一种借助酶催化化学反应实现原位凝固的崭新近净尺寸陶瓷成型概念的直接凝固注浆成型方法与技术，以及通过与陶瓷粉料混合形成浓悬浮胶体的有机单体在加人偶联剂、催化剂和引发剂后的聚合反应促成原位聚合凝固的注疑成型方法与技术。利用这两种成型技术可以获得均匀、无密度梯度的近净尺寸坯体和致密陶瓷制品。这里也简单介绍和讨论了喷墨打印成型技术。它是一种利用计算机控制实现多层打印、逐层叠加制出三维陶瓷坯体的计算机辅助制造(CAM)陶瓷的成型新技术。     

Potential Dental Biofilm Inhibitors: Dynamic Combinatorial Chemistry Affords Sugar-Based Molecules that Target Bacterial Glucosyltransferase

We applied dynamic combinatorial chemistry (DCC) to find novel ligands of the bacterial virulence factor glucosyltransferase (GTF) 180. GTFs are the major producers of extracellular polysaccharides, which are important factors in the initiation and development of cariogenic dental biofilms. Following a structure-based strategy, we designed a series of 36 glucose- and maltose-based acylhydrazones as substrate mimics. Synthesis of the required mono- and disaccharide-based aldehydes set the stage for DCC experiments. Analysis of the dynamic combinatorial libraries (DCLs) by UPLC-MS revealed major amplification of four compounds in the presence of GTF180. Moreover, we found that derivatives of the glucose-acceptor maltose at the C1-hydroxy group act as glucose-donors and are cleaved by GTF180. The synthesized hits display medium to low binding affinity (K_D values of 0.4–10.0 mm ) according to surface plasmon resonance. In addition, they were investigated for inhibitory activity in GTF-activity assays. The early-stage DCC study reveals that careful design of DCLs opens up easy access to a broad class of novel compounds that can be developed further as potential inhibitors.