壳聚糖接枝丙烯酸/丙烯酰胺水凝胶的制备及性能

以丙烯酸(AA)、丙烯酰胺(AM)两种单体同时对壳聚糖(CTS)进行接枝改性,合成了具有环境响应性的壳聚糖水凝胶,讨论了各合成因素对凝胶溶胀性能的影响及凝胶对pH值、离子强度和温度的响应性。结果表明,当反应时间为2h~2.5 h、单体与CTS质量比为8∶1、反应温度在60℃左右、引发剂用量为0.35%(占单体和CTS总量的百分比,下同)、交联剂用量为0.125%时,制得的水凝胶最高溶胀度可达224 g/g,而且该凝胶同时具有pH值、离子强度和温度敏感性。     

壳聚糖接枝丙烯酸高吸水性树脂的制备及性能研究

以壳聚糖(CTS)和丙烯酸(AA)为原料进行接枝共聚,制得高吸水性树脂.通过单因素及正交试验考察AA∶CTS比值、引发剂用量及交联剂用量对树脂吸水性能的影响,确定最佳合成条件.利用红外光谱对产品结构进行表征.结果表明,当AA∶CTS为10∶1,引发剂用量为单体质量的3.5％,交联剂用量为单体质量的0.35％,所制得的树脂吸水率最高,其吸蒸馏水率可达964 g/g,吸盐水率可达58g/g.     

壳聚糖接枝共聚制备高吸水性树脂的研究

以壳聚糖(CTS),丙烯酸(AA),丙烯酰胺(AM)为原料,N,N-亚甲基双烯酰胺(MBAM)为交联剂,NaH-SO3/K2S2O8氧化还原体系为引发剂,通过接枝共聚合反应制备高吸水性树脂。较佳制备条件为:m(CTS)∶m(AA)∶m(AM)为1∶3∶1,丙烯酸的中和度为70%,引发剂用量4%,交联剂用量0.04%,反应温度45℃。研究表明,此条件下所得树脂吸水率为402g/g,吸盐水(浓度0.9%)率为102g/g,并最后采用红外光谱、扫描电镜表征分析了树脂的结构。     

耐盐型壳聚糖高吸水树脂的制备及其性能

以天然无毒、可降解性、抑菌性能良好的壳聚糖(CS)为基体,利用自由基接枝聚合法接枝丙烯酸(AA)和2-甲基丙烯酰胺基-2-甲基丙磺酸单体(AMPS),制备了吸水性和耐盐性能良好的CS高吸水树脂。研究了各因素(温度、投料比、引发剂用量和交联剂用量等)对吸水性及耐盐性的影响,并用红外光谱及扫描电镜对高吸水树脂的结构和形貌进行表征。结果表明:在温度60℃、物料比m(CS)∶m(AA)∶m(AMPS)=1∶8∶3、交联剂用量及引发剂用量均为单体质量1%的条件下,合成的高吸水树脂最大吸水率达578.7g/g,吸盐率达114.2g/g;1h基本达到吸水平衡,且重复使用5次后,吸水率变化不大,重复使用性能良好。     

新型耐盐性高吸水性树脂的制备及性能研究

采用水溶液聚合法,以黄原胶(XG)为原料与丙烯酸(AA)接枝共聚制备了耐盐性高吸水性树脂,利用红外光谱对产物结构进行了表征,考查了合成条件对所制得树脂吸水性能的影响.结果表明XG与AA发生了接枝聚合反应,在聚合温度为60℃,m(AA)/m(XG)=6,AA中和度为70%,引发剂和交联剂与AA单体质量比分别为0.07和0.04时,所得树脂吸纯水倍率为1216g/g,吸盐水倍率为421g/g,且吸水速率适中,保水性能良好,是一种新型耐盐性高吸水性树脂.     

溶液聚合法制备壳聚糖-聚乙烯醇-聚丙烯酸高吸水树脂及其性能研究

壳聚糖(CTS)、聚乙烯醇(PVA)、丙烯酸(AA)作为原料,引发剂采用过硫酸钾(KPS),交联剂选用N,N’-亚甲基双丙烯酰胺(NMBA),通过接枝共聚合成壳聚糖-聚乙烯醇-聚丙烯酸高吸水性复合树脂,并用红外光谱对其结构进行了表征,同时以丙烯酸量为基准。系统研究了壳聚糖、聚乙烯醇与丙烯酸的质量比,引发剂和交联剂的用量,中和丙烯酸的百分比、反应所需的时间和温度对复合吸水树脂吸水性能的影响。结果显示:当壳聚糖、聚乙烯醇与丙烯酸的用量比分别为0.06和0.3,引发剂和交联剂用量分别为1.5%和0.23%,中和丙烯酸的百分比为55%,反应时间为5h,反应温度为45℃,所合成的壳聚糖-聚乙烯醇-聚丙烯酸高吸水树脂吸(盐)水率最高,分别为340倍与64倍。     

水溶液法合成丙烯酸系耐盐性高吸水树脂

本研究采用水溶液法合成(以丙烯酸为单体)丙烯酸系高吸水树脂(耐盐性),探讨了单体中和度、引发剂用量、交联剂用量、聚合温度等因素对高吸水树脂(SAP)吸水性能的影响。通过引入无机氧化物提高高吸水树脂的耐盐性,并对无机氧化物的形式和用量对高吸水树脂吸水性能的影响进行了研究。通过大量实验对高吸水树脂性能进行优化,获得丙烯酸系SAP的最佳合成工艺:引发剂为(NH_4)_2S_2O_8/Na_2SO_3,反应温度70℃,反应时间4h以及80%的中和度;用量:正硅酸四乙酯1wt%,交联剂0.03wt%,Na_2SO_30.1wt%,(NH_4)_2S_2O_80.2wt%。结果表明,合成得到的SAP样品吸水量和0.9wt%生理盐水吸收量分别为1139g/g和91g/g。     

PVA/CTS/P(AA-AMPS)互穿网络结构高吸水树脂耐盐性和防潮性能研究

以过硫酸钾(KPS)为引发剂,N,N′-亚甲基双丙烯酰胺(NMBA)为交联剂,丙烯酸(AA)和2-丙烯酰胺-2-甲基丙磺酸(AMPS)为单体,壳聚糖(CTS)为天然聚合物,聚乙烯醇(PVA)为合成聚合物,采用水溶液聚合法合成了互穿网络结构高吸水性树脂[PVA/CTS/P(AA-AMPS)],并对其进行了表征。考察了引发剂用量、交联剂用量、CTS用量和PVA用量对树脂吸液性能的影响。在最佳反应条件下,PVA/CTS/P(AA-AMPS对蒸馏水和0.9%(wt,质量分数)的氯化钠溶液的吸附量分别为1800g/g和110g/g。暴露在空气中8d条件下的吸湿性低于单层网络的87.5%,在不同阳离子盐溶液中(Na~+、Ca~(2+)和Fe~(3+))的吸液性能也明显优于单层网络。     

多孔膨润土/丙烯酸/羧甲基纤维素复合凝胶的制备及性能研究

以纳米膨润土、丙烯酸和羧甲基纤维素为原料,N,N’-亚甲基双丙烯酰胺为交联剂,聚乙烯醇(PEG)为成孔剂制备了一种新型多孔网络凝胶。通过红外光谱(FT-IR)、X射线衍射(XRD)和扫描电镜(SEM)对凝胶结构进行了表征。研究了交联剂、引发剂用量和成孔剂的加入对凝胶的溶胀性能的影响。结果表明:交联剂量为0.04wt%,引发剂量为1.5~2.0wt%时多孔凝胶的溶胀性能最佳。在蒸馏水中和0.9wt%NaCl溶液中的溶胀率分别1125g/g和123g/g。成孔剂PEG的加入能使凝胶的溶胀率和溶胀速率明显提高。     

CTS-g-PAA/ATP水凝胶制备及对染料的吸附性能

以壳聚糖(CTS)、丙烯酸(AA)、凹凸棒石黏土(ATP)为原料,采用微波辐射法,通过接枝共聚合成了CTS-g-PAA/ATP水凝胶,利用FTIR和SEM分析了树脂的结构,探讨了水凝胶对亚甲基蓝的吸附性能和吸附机理。结果显示:GA、ATP和AA发生了接枝共聚反应,形成均匀的三维网络复合高吸水凝胶。在200 mL浓度为200 mg/L,加入2 mmol/L的NaCl、SDS的MB溶液中,凝胶对MB的吸附量分别147、330 mg/g。溶液pH在4～7之间时,凝胶对MB吸附量保持恒定的吸附能力,吸附量为300 mg/g。水凝胶对MB的吸附应用Freundlich方程比Langmuir方程更适合实验数据,吸附动力学符合准二级动力学模型,吸附过程属于化学吸热反应过程。     

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。     

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。     

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.     

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.     

SMC／BMC的回收与再利用

SMC／BMC废弃物对工业及环境造成了很大影响，指出了SMC／BMC回收再利用的紧迫性。通过对目前国际上SMC／BMC回收再利用的3种典型途径优缺点的对比，参照国外SMC／BMC回收再利用的先进方法，对我国SMC／BMC回收再利用提供了可行的建议．     

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。     

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.