氟硅改性丙烯酸酯无皂乳液的制备及性能

以纳米SiO2(Nano-SiO2)、γ-甲基丙烯酰氧乙基三甲氧基硅烷(KH570)、全氟烷基乙基丙烯酸酯(FM))等为主要原料,通过KH570改性纳米SiO2后,与FM等乙烯基单体共聚,制得了既含氟又含硅的丙烯酸酯有机/无机杂化无皂乳液。通过FT-IR、AFM及接触角测量等手段研究了共聚物的结构及性能。结果表明,氟硅单体均参与了共聚反应;乳胶膜耐热稳定性及残炭率均得以提高;加入SiO2后,涂膜凸起峰的高度和致密程度提高;当w(FM)=30%,w(SiO2)=0.5%时,涂膜对水及液体石蜡的接触角分别为125°及110°;激光粒度分布仪(DLS)分析表明,乳液平均粒径为98.37 nm。     

耐水增强丙烯酸酯乳液的研究进展

综述了耐水增强丙烯酸酯乳液改性研究新进展,介绍了采用有机硅、有机氟、环氧树脂和交联单体对丙烯酸酯乳液进行改性的理论依据及发展现状,对核-壳乳液聚合、无皂乳液聚合、互穿网络聚合、有机无机复合乳液聚合等改性方法与机理进行了全面阐述,并展望了耐水增强丙烯酸酯乳液改性的发展趋势。     

无皂硅丙胶乳表面施胶剂的制备及对纸张的增强作用

以γ-甲基丙烯酰氧丙基三甲氧基硅烷(KH570)作自交联单体,聚乙烯醇(PVA)为高分子胶体稳定剂,苯乙烯(St)、丙烯酸丁酯(BA)、甲基丙烯酸(MAA)为单体采用无皂种子聚合制备了稳定性好、性能优异的无皂硅丙乳液表面施胶剂,并优化了合成工艺条件。结果表明,当w(MAA)=2%~3%,软硬单体比例n(BA)/n(St)=2~2.5,w(PVA)=10%~15%,w(KH570)=5%时,无皂硅丙乳液表面施胶剂具有优异的施胶效果;以质量分数为1.0%的聚合物乳液进行表面施胶时,纸张施胶度可达14.5 s,表面强度达3.69 m/s,耐折度3300次。     

无皂乳液聚合制备纳米SiO_2/丙烯酸酯复合乳液

在丙烯酸酯乳液无皂聚合过程中引入正硅酸乙酯,利用原位水解形成的纳米SiO2粒子制备了具有互穿网络结构的纳米SiO2/聚丙烯酸酯复合乳液。采用傅立叶红外光谱、透射电镜、粒度分析仪、热分析仪以及拉力实验机等表征了复合乳液的结构、形态、粒径、耐热性以及力学等性能。研究了反应型乳化剂对复合乳液的耐水性和粒径及其分布的影响,以及不同的正硅酸乙酯用量对复合乳液热学性能和力学性能的影响。结果表明,复合乳液的耐水性优异,粒径小、单分散性好。SiO2无机网络在丙烯酸酯聚合网络中起到了交联点的作用,并与有机相之间有良好的键合;复合乳液的热稳定性和摆杆硬度随着正硅酸乙酯(TEOS)用量的增加而增强,而拉伸强度、断裂延伸率则先增大后减小。     

二氧化硅纳米微球的制备及其表面改性

以正硅酸四乙酯(TEOS)为前驱体,氨水为催化剂,经Stber法制备了单分散SiO2纳米微球,并采用硅烷偶联剂KH-570对其表面进行了改性;通过激光粒度分析仪、傅里叶变换红外光谱、透射电子显微镜对SiO2纳米微球进行了检测分析。结果表明,随着TEOS和氨水用量的增加,SiO2纳米微球的粒径逐渐增大,而粒径分布到后期也有所增加;经KH-570改性后,SiO2纳米微球不仅具有良好的单分散性,而且表面成功接枝上丙烯酸酯基团,因而具有较好的亲油性,能更好地分散在甲苯和苯乙烯中。     

苯乙烯-丙烯酸酯树脂/纳米SiO2核壳乳液的制备及性能

以聚乙烯醇为保护胶体,以含双键的纳米SiO2粉体与丙烯酸酯类单体通过原位无皂乳液聚合合成了苯乙烯-丙烯酸酯树脂/纳米SiO2核壳乳液。通过红外光谱(FT-IR)、透射电镜(TEM)、扫描电镜和接触角测试对杂化材料进行表征,结果表明纳米SiO2和丙烯酸酯之间产生了化学键的结合,两者复合达到分子水平。材料力学性能和耐水性均好,其中拉伸强度最高可达5.5N/mm2,断裂伸长率可达到102%;耐水性最低为12.5%。     

PBS/SiO2纳米复合材料的制备及其结构与性能分析

以聚丁二醇丁二酸酯（PBS）为基材,经-甲基丙烯酰氧基丙基三甲氧基硅烷偶联剂（KH570）改性过的纳米SiO2和未改性的SiO2为填料,采用熔融共混法制备了PBS/SiO2纳米复合材料。研究了所得纳米复合材料的热稳定性能、力学性能和降解性能等。结果表明：当经KH570表面改性的纳米SiO2（KH570与纳米SiO2的质量之比为1：5）的添加质量分数为4%时,复合材料的维卡软化点约提高了10℃,拉伸强度约提高30%,同时复合材料的降解性能比PBS纯料的降解性能有一定的提高。     

核壳型纳米SiO_2改性含氟聚丙烯酸酯乳液稳定性的研究

采用无皂乳液聚合技术和核壳粒子设计,合成了核壳型纳米SiO2改性含氟聚丙烯酸酯无皂乳液,采用透射电镜观察了乳液粒子形态。研究结果表明,采用反应性乳化剂制备的无皂乳液稳定性更好,当反应温度为83℃、引发剂用量为1.1%、反应性乳化剂用量为4%时,所得乳液稳定性好,转化率高,凝胶较少;随着含氟单体用量的增加,乳液聚合稳定性及转化率逐渐降低。     

含氨基的改性氟硅丙烯酸酯乳液的制备

采用半连续乳液聚合法在丙烯酸正丁酯(BA)、甲基丙烯酸甲酯(MMA)和乙烯基三乙氧基硅烷(VTES)共聚物上通过烷氧基水解缩合成功引入了含氟硅单体甲基三氟丙基环三硅氧烷(D3F)及含氨基基团的Γ-氨基三乙氧基硅烷(KH550),得到的改性丙烯酸酯乳液可用于提高织物的疏水性能。通过正交实验得出了最佳反应工艺:反应温度为80℃、氟硅单体量占单体总质量的25%,KH550的量占单体总质量的4%,D3F的量占单体总质量的4%。对所获得乳液进行了红外、透射电镜、粒径和热重等一系列测试,结果表明,乳胶粒粒径分布均匀,大小在125 nm左右,热重表征得出熔融温度(Tmax)480℃,乳液涂覆在棉和真丝上与水的接触角达到了125.8°和120.7°。     

含氨基的改性氟硅丙烯酸酯乳液的制备EI北大核心CSCD

采用半连续乳液聚合法在丙烯酸正丁酯(BA)、甲基丙烯酸甲酯(MMA)和乙烯基三乙氧基硅烷(VTES)共聚物上通过烷氧基水解缩合成功引入了含氟硅单体甲基三氟丙基环三硅氧烷(D3F)及含氨基基团的Γ-氨基三乙氧基硅烷(KH550),得到的改性丙烯酸酯乳液可用于提高织物的疏水性能。通过正交实验得出了最佳反应工艺:反应温度为80℃、氟硅单体量占单体总质量的25%,KH550的量占单体总质量的4%,D3F的量占单体总质量的4%。对所获得乳液进行了红外、透射电镜、粒径和热重等一系列测试,结果表明,乳胶粒粒径分布均匀,大小在125 nm左右,热重表征得出熔融温度(Tmax)480℃,乳液涂覆在棉和真丝上与水的接触角达到了125.8°和120.7°。     

凝固科学技术与材料

从凝固科学与实践发展的角度介绍了当前凝固材料体系的基本框架和凝固科学主要发展阶段的基本理论。作为材料科学与工程的基本组成，凝固科学技术正在现代科学理论的基础上针对传统材料的改性提高和新材料的发展需求，以控形、控构、控性为目标开展优质铸件的定向、晶体生长、快凝、深过冷及各种新型和超常领域凝固过程的研究，并介绍了其中某些方面和展望了可能的发展趋势。     

Development and challenges of planning and scheduling for petroleum and petrochemical production

Production planning and scheduling are becoming the core of production management, which support the decision of a petrochemical company. The optimization of production planning and scheduling is attempted by every refinery because it gains additional profit and stabilizes the daily production. The optimization problem considered in industry and academic research is of different levels of realism and complexity, thus increasing the gap. Operation research with mathematical programming is a conventional approach used to address the planning and scheduling problem. Additionally, modeling the processes, objectives, and constraints and developing the optimization algorithms are significant for industry and research. This paper introduces the perspective of production planning and scheduling from the development viewpoint.     

江澳两地高校文创设计的协同研究与商业实践

目的 探索江门世遗文化的传承、发展和转化的新思路,践行国家在《粤港澳大湾区发展规划》纲要中要求江门承担与港澳地区文化创意合作与开发任务的分工。方法 与澳门高校紧密合作,开展专业培训课程,以开平碉楼为例,从人文视角开展设计研究,梳理开平碉楼的文化脉络,把世遗文化的元素和其背后的文化融入文创产品中,提升文创产品的附加值,推动当地文创产业结构的变革。结果 两地高校构建了稳定的科研团队,开设长期有效的设计培训课程,与景区建立了研究协作关系,帮助景区构建了一套产销研的商业模式。结论 以跨区域高校合作为平台,以文创产品为抓手,依托江澳两地的资源优势,可以构建江门世遗文化全新的品牌形象,最终推动开平世遗文化的活化。     

The Candela and Photometric and Radiometric Measurements

The national measurement system for photometric and radiometric quantities is presently based upon techniques that make these quantities traceable to a high-accuracy cryogenic radiometer. The redefinition of the candela in 1979 provided the opportunity for national measurement laboratories to base their photometric measurements on optical detector technology rather than on the emission from high-temperature blackbody optical sources. The ensuing technical developments of the past 20 years, including the significant improvements in cryogenic radiometer performance, have provided the opportunity to place the fundamental maintenance of photometric quantities upon absolute detector based technology as was allowed by the 1979 redefinition. Additionally, the development of improved photodetectors has had a significant impact on the methodology in most of the radiometric measurement areas. This paper will review the status of the NIST implementation of the technical changes mandated by the 1979 redefinition of the candela and its effect upon the maintenance and dissemination of optical radiation measurements.     

Creation and motion of dislocations and fracture in metal and silicon crystals

By making a step on one surface ( ) of a rectangular small paralellepiped copper crystal, dislocations could be created by the molecular dynamic method. The dislocation created was not a complete edge dislocation but a pair of Heidenreich-Shockley partial dislocations. Each time a dislocation was created, the stress on the surface was released. Small copper crystals having a notch were pulled (until fracture), compressed and buckled by use of the molecular dynamic method. An embedded atom potential was used to represent the interaction between atoms. Dislocations were created near the tip of the notch. A very sharp yield stress was observed. The results of high speed deformations of pure silicon small crystals using the molecular dynamics are presented. The results suggest that plastic deformation may be possible for the silicon with a high speed deformation even at room temperature. Another small size single crystal, the same size and the same surfaces, was compressed using molecular dynamic method. The surfaces are {110}, {112} and {111}. The compressed direction was [111]. It was found that silicon crystals are possible to be compressed with a high speed deformation. This may suggest that silicon may be plastically deformed with high speed deformation.     

Error and uncertainty in modeling and simulation

This article develops a general framework for identifying error and uncertainty in computational simulations that deal with the numerical solution of a set of partial differential equations (PDEs). A comprehensive, new view of the general phases of modeling and simulation is proposed, consisting of the following phases: conceptual modeling of the physical system, mathematical modeling of the conceptual model, discretization and algorithm selection for the mathematical model, computer programming of the discrete model, numerical solution of the computer program model, and representation of the numerical solution. Our view incorporates the modeling and simulation phases that are recognized in the systems engineering and operations research communities, but it adds phases that are specific to the numerical solution of PDEs. In each of these phases, general sources of uncertainty, both aleatory and epistemic, and error are identified. Our general framework is applicable to any numerical discretization procedure for solving ODEs or PDEs. To demonstrate this framework, we describe a system-level example: the flight of an unguided, rocket-boosted, aircraft-launched missile. This example is discussed in detail at each of the six phases of modeling and simulation. Two alternative models of the flight dynamics are considered, along with aleatory uncertainty of the initial mass of the missile and epistemic uncertainty in the thrust of the rocket motor. We also investigate the interaction of modeling uncertainties and numerical integration error in the solution of the ordinary differential equations for the flight dynamics.     

PSD和PWELCH函数的分析改进及应用

针对MATLAB中两个内建功率谱密度计算函数psd()和pwelch()计算结果迥异的现象,在功率谱密度估计理论的基础上,根据经典的周期图理论和Welch平均周期图方法,通过详细分析源程序,解析计算方法,发现psd()计算的并不是工程单边功率谱密度,而是采样信号双边谱,故与pwelch()结果迥异,另外pwelch()不能对分段信号数据进行预处理。就上述不足提出了相应的改进措施,比较验证表明改进措施行之有效。     

Density and viscosity of tetralin and trans-decalin

New measurements are reported for the density and viscosity of tetralin and trans-decalin. The density was determined from room temperature to 60°C for tetralin and to 95°C for trans-decalin. The kinematic viscosity was measured up to temperatures slightly above 100°C. Our results improve upon the values recommended by the American Petroleum Institute for these liquids.