复合阻燃装饰板的GC/MS分析及卫生学评价

采用GC/MS联用技术对复合阻燃装饰板常温和高温状态下的气体释放物成分进行定性和定量的分析。检测结果显示,在封箱实验期间,复合阻燃装饰板常温下释放的9种主要气体浓度没有超过GJB11.3—91标准容许浓度;高温下材料热解的气体释放物主要有35种,采用动物急性吸入试验对该材料进行高温热解物毒性检测,其动物急性吸入半数致死浓度LC50为180.8 g/m3,该材料为低等毒性材料。     

胎基材料对沥青燃烧性能测试的影响

选用玻璃棉、棉布、聚酯毡3种胎基材料分别制备沥青、阻燃沥青试样,利用极限氧指数测定仪测试其点火时间、燃烧时间以及极限氧指数,分析胎基材料对沥青、阻燃沥青燃烧性能测试结果的影响。实验结果表明,沥青、阻燃沥青试样的LOI值会因胎基材料的不同存在差异。本次研究选用的3种胎基材料中,相较于棉布与聚酯毡,玻璃棉更适合用于制备沥青、阻燃沥青试样。     

微孔聚氨酯弹性体材料水解稳定性研究

采用相同分子量的聚醚、聚酯和聚醚酯二元醇为原料分别制备密度为0．55g／cm3左右的微孔聚氨酯弹性体（MPUE）材料。并通过一系列测试对这三种微孔聚氨酯弹性体材料进行分析对比。结果发现聚醚型微孔聚氨酯弹性体材料的耐水解性能非常优异,聚酯型微孔聚氨酯弹性体材料的力学性能最好,聚醚酯型微孔聚氨酯弹性体材料的力学性能与聚酯型的力学性能接近,耐水解性能远优于聚酯型,近似于聚醚型。     

表面除杂处理对碳素纤维毡红外发射率的影响

为优化碳素纤维电热体红外辐射性能,测定了碳素纤维毡表面除杂处理前后的法向光谱发射率和法向总发射率,利用X射线衍射和拉曼光谱进行样品的物相结构分析,研究了表面除杂处理过程物相结构变化与碳素纤维毡法向光谱发射率和总发射率的关系.结果表明：采用硝酸液相除杂和空气瞬时高温2种方式处理时,碳素纤维毡的法向光谱发射率均出现一定的波...     

废旧材料的高温热解回收研究进展

热解是有机物在无氧或缺氧的环境中,通过加热在高温条件下发生分解的反应。废旧材料可以通过热解处理实现资源的循环再利用。废旧材料的高温热解回收不仅能够有效减轻其对环境的污染,而且还可以实现资源的再利用。本文从废旧塑料、废旧塑料/金属复合材料(印刷电路板)、废旧橡胶和生物质四方面分别介绍了高温热解在废旧材料回收利用领域的应用,具体介绍了每种废旧材料的热解过程和热解产物;最后对热解废旧材料的研究所存在的问题和面临的挑战进行了总结和展望,期望对其他废旧材料的高温裂解回收奠定基础。     

薄膜印刷前不同方式预处理各有何作用?

<正>等离子体处理通过放电装置将电离的等离子体中的电子或离子打到承印物表面,一方面,可以打开材料的长分子链,出现高能基团;另一方面,经打击使薄膜表面出现细小的针孔,同时还可使表面杂质离解、重解。电离时放出的臭氧有强氧化性,附着的杂质被氧化而除去,使承印物表面自由能提高,达到改善印刷性能的目的。电晕处理利用高频(中频)高压电源,在放电刀架和刀片的间隙产生一种电晕释放现象,用这种方法对塑料薄膜在印刷前进行表面处理,叫电     

4-羟基丁酸含量对聚 3-羟基丁酸 与 4-羟基丁酸共聚物性能和结构的影响

目的对3-羟基丁酸4-羟基丁酸共聚酯P(3HB-co-4HB)进行酶解测试。方法通过力学性能测试、失重率分析、热失重分析、X-射线衍射分析、扫描电镜等测试和表征手段对样品的物理性能及生物降解情况进行评价。结果 P(3HB-co-4HB)分子中4HB单体(文中均用摩尔分数表示)的引入提高了材料的柔韧性,材料的脆性下降;失重率方面,4种材料的降解速率从高到低依次为P(3HB)P(3HB-co-5%4HB)(3HB-co-10%4HB)P(3HB-co-15%4HB);酶解前期,材料的热稳定性增强,而酶解后期材料的热稳定性逐渐下降;XRD结果表明材料降解过程中结晶度的变化不明显;P(3HB-co-4HB)分子中随着4HB单体含量的增加,材料表面粗糙度降低,酶解后材料表面被侵蚀,降解速率与失重率结果一致。结论 P(3HB-co-4HB)分子中4HB单体的引入显著影响了材料的机械性能,随着4HB含量的增加,材料的失重率越来越大,热稳定性呈现先上升后下降的趋势,材料表面粗糙度逐渐降低,由于酶解过程属于从表面侵蚀开始,因此酶解过程中样品的结晶度变化不大。     

注氘能量对Li_4SiO_4陶瓷热解吸行为的影响

采用离子注入方式对Li_4SiO_4陶瓷进行了25,35,45,55 ke V四种不同能量的氘离子辐照,利用高温热解吸系统模拟研究了其中的氘释放行为。实验结果表明,D+辐照Li_4SiO_4陶瓷离子投影射程深度随注入能量的增大呈线性增加趋势,引入的平均离位损伤程度呈减小趋势;不同注氘能量Li_4SiO_4样品的高温热解吸谱中,分子氘的热解吸过程主要分布在低温区域(300~550℃)及高温区域(550~750℃),氘化水释放温度集中在高温区域600~780℃;D2O为主要释放形式;注氘样品表面存在密度不均匀的类圆形泡状、坑状缺陷、孔洞状结构;热解吸后样品表面发生了重构。     

Pt掺杂介孔TiO_2/导电碳毡光电极的制备及光电催化性能

以四氯化钛为钛源、十六烷基三甲基溴化铵为模板剂、氯铂酸为掺杂离子、导电碳毡为载体,通过水热合成法制得液晶-Pt离子-无机物钛前驱体溶液,在超声波辅助下采用浸渍提拉法进行负载,在氮气保护下焙烧得到导电碳毡负载铂掺杂介孔TiO_2(TiO_2-Pt/CCF)光电极,利用现代表征手段对材料结构进行表征。以苯甲醛为目标降解物,对材料的光电催化活性进行研究,并分析了光电协同机制。结果表明:介孔化处理提高了TiO_2-Pt/CCF的比表面积,增大了降解反应的有效面积和催化剂表面降解物浓度;金属离子掺杂引入了杂质能级,减小了TiO_2的能带隙,同时,Pt充当着光生电子-空穴捕获阱,阻止电子-空穴对的复合,提高了TiO_2-Pt/CCF的光电催化效率;TiO_2固载化提高了对目标降解物的吸附和表面电子转移。在多功能的协同改性下,TiO_2-Pt/CCF比无孔TiO_2/CCF和介孔TiO_2/CCF有更高的催化活性。     

硬质隔热用炭纤维整体毡的制备工艺研究

以预氧化纤维网胎为原料,经过接力层叠针刺工艺制备的预氧化纤维整体毡为预制体,在不同的炭化条件下得到炭纤维整体毡,并以热固性树脂为先驱体,采用浸渍—固化—树脂炭化—石墨化的方法制备了硬质隔热用炭纤维整体毡。研究了针刺工艺、炭化温度、浸渍液浓度和固化时所加压力等因素对材料密度的影响,并借助扫描电镜观察样品的微观结构。结果表明:采用高的针刺密度和针刺深度参数,得到的预制体密度较大;炭化温度对整体毡密度的影响不大,但其含碳量随炭化温度变化明显;浸渍液浓度及预制体密度均对硬质毡的密度有一定影响;随着固化时压力的增大,样品的密度也逐渐提高。     

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。     

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.     

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.     

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.