壳聚糖静电吸附羧基磷酰胆碱聚合物的研究

采用饥饿法聚合合成了3种不同配比的甲基丙烯酰氧乙基磷酰胆碱-甲基丙烯酸二元共聚物(poly(MPC-co-MA),PMA),并将其静电吸附在壳聚糖表面(CS-PMA)。通过动态接触角(DCA)对影响静电吸附改性的盐及聚合物组成因素进行研究。用X-射线光电子能谱(XPS)、原子力显微镜(AFM)对改性壳聚糖膜的表面元素组成、形貌进行表征,并通过血小板黏附实验对其抗凝血性能进行评价。结果表明,这种利用静电吸附的方式将磷酰胆碱聚合物吸附在壳聚糖表面,可获得具有仿细胞外层膜结构的涂层表面。与壳聚糖相比,改性后壳聚糖可以显著降低对血小板的黏附,抗凝血性能显著提高。该研究为构建仿细胞外层膜结构改善材料血液相容性提供了一种简单、便捷的方法。     

两性离子聚合物表面改性的聚偏氟乙烯抗污染膜的制备及性能

提高聚偏氟乙烯(PVDF)抗污染性能是改善PVDF应用效果的重要途径。文中通过自由基聚合的方法将抗污染材料——两性离子类化合物磺酸甜菜碱(DMAPS)接枝到碱处理过的PVDF膜表面。研究了接枝DMAPS后,PVDF膜表面的结构与性能变化,并初步探讨了改性后的PVDF膜对牛血清蛋白的吸附性能。结果表明,在PVDF膜表面接枝DMAPS后,膜表面孔洞减小,亲水性提高。虽然改性后的PVDF膜通量有所下降,但通过牛血清蛋白(BSA)的振荡吸附实验发现,两性离子改性膜表现出良好的抗蛋白质吸附性能。与PVDF原膜相比,改性膜在BSA溶液中通量下降率小,用水清洗后膜通量恢复率高。     

羧甲基化香菇多糖对壳聚糖表面的化学修饰

以壳聚糖为基材,通过表面化学接枝修饰的方法,将羧甲基化香菇多糖固定在壳聚糖基材的表面。通过红外光谱、水接触角测试、抗菌活性及蛋白质吸附等测试方法对修饰后的壳聚糖表面性能进行了表征和分析。测试结果表明,经过表面接枝修饰的壳聚糖基材表面的亲水性得到明显改善,表面纤维蛋白原的吸附量降低了61%,显示出明显的排斥蛋白质非特异性...     

低温等离子体表面处理PEGDA/HEMA水凝胶的时效性及亲水性

采用低温等离子体工艺对聚乙二醇双丙烯酸酯(PEGDA)/甲基丙烯酸-2-羟基乙酯(HEMA)共聚物凝胶膜进行表面改性,研究了等离子处理的时效性,通过紫外接枝法在等离子处理材料表面接枝丙烯酰胺(AAm),并探讨了时效性对丙烯酰胺接枝率的影响和表面改性后材料的亲水性。研究结果表明,氩等离子处理凝胶材料具有一定的时效性,随着放置时间的延长,AAm的接枝率降低,接枝后PEGDA/HEMA材料的亲水性得到改善,材料的亲水性随着AAm的浓度的增大而增大。     

防潮活性炭的制备及防潮性能研究

为提高活性炭防潮能力,减小净化空气时对环境湿度的影响,配制全氟辛基三乙氧基硅烷甲醇溶液,并对椰壳活性炭表面进行氟化改性。利用SEM、EDS、BET等手段进行表征,结果表明,单体F8261通过化学键作用结合在活性炭表面,实现了疏水性,且对孔隙结构影响极小。在相对湿度为90%的湿润环境中,测得增重比差值最大可达13%;水浸泡后,测得吸附系数差值最大可到203.26mg/g。证明了氟化处理对提高活性炭防潮能力具有一定的现实意义。     

活性炭的双氧水表面改性及其吸附二氧化硫性能研究

目的 制备武器装备贮存微环境用单组分的二氧化硫吸附材料。方法 采用双氧水对椰壳活性炭进行表面改性,研究改性活性炭孔隙结构、表面化学性质的变化及其对二氧化硫吸附性能的影响。结果 活性炭存在微孔和中孔,改性后活性炭比表面积略有增加,平均孔径减小。双氧水与活性炭反应起到刻蚀作用,在活性炭表面产生了纳米尺度的网孔结构,降低了活性炭表面碳微晶有序程度,同时双氧水与活性炭反应时起到了氧化作用,提升了活性炭表面氧元素和含氧官能团含量。体积分数为20%的双氧水改性活性炭的吸附容量最高,达到154.15 mg/g,约为改性前的5倍。结论 双氧水对活性炭经表面改性后,产生了纳米尺度的孔隙,并提升了活性炭表面含氧官能团,在两者协同作用下显著提升活性炭对SO₂吸附性能,具有良好的装备应用前景。     

活性炭对VOCs的吸附研究进展

挥发性有机化合物(VOCs)是大气主要污染物之一,包括烃类化合物和芳香族化合物,如乙二醇和苯等.VOCs不仅导致温室效应,破坏臭氧层,而且当其浓度偏高时,会引起人体不适,严重时危及生命,因此如何有效地处理VOCs成为学术界和工业界的研究热点.目前,处理VOCs的技术众多,包括催化氧化等破坏性回收技术和吸附等可恢复性技术.相比于在回收过程中不可避免会产生有毒副产物的破坏性回收技术,吸附技术具有VOCs回收效率高、操作简单、能量消耗低等优点,因而被广泛应用.吸附技术的核心是吸附剂.活性炭因具有较高的比表面积、良好的孔道结构以及易于表面官能团改性等优点,被认为是一种具有潜力的VOCs吸附材料.但目前未经改性的活性炭通常比表面积小、表面官能团含量少、对VOCs的吸附能力和选择性较差且疏水能力差,极大地影响了其在潮湿环境中的应用.鉴于此,本文在介绍活性炭对VOCs吸附和脱附原理的基础上,从活性炭的物理结构和表面化学性质两个角度出发,重点介绍不同改性方法(物理改性、化学改性等)改性后的活性炭对VOCs吸附能力和选择性的影响,并对吸附饱和后活性炭的再生方法进行总结.本文旨在系统总结活性炭对VOCs的吸附、解吸和再生机理,以及活性炭改性技术的最新进展,为制备比表面积大、表面官能团丰富的工业化活性炭提供参考.     

HEMA远程等离子体聚合改性聚丙烯表面的结构及亲水性能

采用甲基丙烯酸羟乙酯(HEMA)的远程等离子体聚合方法对聚丙烯(PP)表面进行改性,以聚合量、浸水失重、红外光谱(FT-IR)、扫描电镜(SEM)和水接触角等测试手段,研究了远程距离对改性表面的化学结构、形态结构及亲水性的影响。结果表明,随着远程距离的增加,由于等离子体中高能粒子的轰击、刻蚀作用减轻,HEMA逐渐从气相聚合过渡到表面聚合过程,改性表面的聚合量、酯基及羟基等基团含量、线性结构聚合物含量和表面亲水性能等随之提高,远程位置28.8cm样品表面保留的HEMA单体的羟基结构最多,接触角下降至18.6°。     

金属离子改性活性炭对二氯甲烷/三氯甲烷吸附性能的影响

主要研究了不同金属改性活性炭对三氯甲烷和二氯甲烷吸附性能的影响.采用浸渍法将4种不同金属离子负载改性活性炭,测定了三氯甲烷和二氯甲烷在改性活性炭上的吸附透过曲线,应用软硬酸碱理论分析和讨论了活性炭表面负载不同金属离子对二氯甲烷吸附性能的影响.结果表明,不同金属负载活性炭对三氯甲烷和二氯甲烷的吸附能力依次为:Fe(Ⅲ)-AC＞Mg(Ⅱ)-AC＞Cu(Ⅱ)-AC＞AC＞Ag(I)-AC,根据软硬酸碱理论分类,三氯甲烷和二氯甲烷属于硬碱,当活性炭表面负载硬酸类金属离子Fe~(3+)、Mg~(2+),增大了活性炭表面的硬酸性,对三氯甲烷和二氯甲烷的吸附能力加强,Ag~+属于软酸,它的负载局部增强了活性炭表面的软酸性,降低了其对三氯甲烷和二氯甲烷的吸附能力.     

还原和氧化改性活性炭对亚甲基蓝吸附性能的影响

分别采用NaOH、NH3.H2O、H2O2以及不同浓度的HNO3溶液对微孔颗粒活性炭浸渍改性,通过静态试验研究了改型活性炭对水溶液中亚甲基蓝吸附特性的研究,并从动力学角度探讨吸附机理。实验结果表明,硝酸改性后表面的羧基含量增加,酚羟基含量减少;氢氧化钠和氨水改性后,碱性基团含量显著增加;硝酸改性后活性炭的吸附量略有增加,碱液改性和硫酸镁改性后活性炭吸附量略有减少。改性后活性炭材料对亚甲基蓝吸附均更符合伪二级吸附模型,R2>0.99。     

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.     

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.     

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。     

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。     

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.     

Miniature and MEMS-type vacuum sensors and pumps

In the paper, the observable trends of the actual research and development of selected types of miniature and MEMS-type vacuum sensors are presented. Some information about the new types of active vacuum gauges, which are offered by the leading manufacturers of the vacuum measurement instruments, is given. Next, the list of MEMS devices that need vacuum for proper operation is presented. Some aspects of vacuum-encapsulation of MEMS devices, on wafer level and package level are shown. The new conceptions of obtaining and maintenance of high and ultra-high vacuum in MEMS devices are described. They concern the conception of integration of a miniature orbitron pump on-chip with MEMS-type device or with vacuum part of the portable advanced instruments such as electron microscope, ion mass spectrometer, and free electron laser.     

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.