激光源原子氧对Kapton薄膜和Kapton／Al薄膜二次表面镜性能的影响

在模拟空间环境原子氧暴露条件下,采用激光源原子氧对热控涂层材料Kapton薄膜、Kapton/Al薄膜二次表面镜进行了不同剂量的暴露试验。研究了这两种材料的质量损失、表面形貌随原子氧暴露剂量的变化关系,以及Kapton薄膜的光谱透过率、Kapton/Al薄膜二次表面镜的光谱反射率和太阳吸收比Δαs随原子氧暴露剂量的演化规律。结果表明:两种材料的质量损失随原子氧暴露剂量的增加呈线性增大;原子氧暴露后,试样表面呈"地毯"状形貌,且随暴露剂量的增加粗糙度变大;Kapton薄膜的光谱透过率、Kapton/Al薄膜二次表面镜的光谱反射率随原子氧暴露剂量的增加而降低,Kapton/Al薄膜二次表面镜的太阳吸收比Δαs随暴露剂量的增加而增大。最后对Kapton薄膜的存在寿命和Kapton/Al薄膜二次表面镜绝热平面的平衡温度进行了预测。     

热循环、真空紫外辐照对Al/Kapton薄膜的损伤效应

在空间环境地面模拟设备中模拟热循环、真空紫外辐照等低地球轨道空间环境对Al/Kapton薄膜的损伤效应.利用原子力显微镜、紫外可见分光光度计对试验前后试样的表面形貌、光学参数等性能进行了分析.结果表明,热循环、真空紫外辐照使Al/Kapton薄膜试样产生质量损失,表面形貌发生不同程度的改变,在紫外可见波段的反射率下降明显.     

模拟空间原子氧对Teflon FEP/Al薄膜性能的影响

在模拟空间环境原子氧辐照的条件下,采用固定的原子氧束流密度进行不同时间的辐照试验,研究了温控材料Teflon FEP/Al薄膜的质量损失、光学性能、表面形貌和表面粗糙度的演化规律.结果表明,材料的质量损失与原子氧的作用时间成正比.辐照前后材料的表面形貌和表面粗糙度发生明显变化,致使太阳吸收率发生明显变化,从而导致材料的光学性能发生变化.     

Kapton/Al薄膜的电子辐照损伤

使用空间综合辐照设备对Kapton/Al薄膜进行了电子辐照的地面模拟实验,研究了Kapton薄膜的表面形貌、光学性能变化和辐照损伤机制.结果表明,辐照使Kapton薄膜表面发生了明显的充放电效应;在500-1000 nm波长区间光谱反射系数明显降低,太阳吸收比随着电子辐照剂量的增加而增高;在辐照过程中Kapton薄膜发生酰亚胺基团的破坏、羰基和桥氧键的断裂以及O在N 逸出空位处的替换,并有较复杂的新结构生成.     

电子对F46镀银二次表面镜光学性能影响研究

空间电子辐照是对航天器用热控材料性能产生影响的重要因素.研究了F46镀银二次表面镜在电子辐照作用下的光学性能和质量损失的变化规律,并应用扫描电镜和电子能谱对电子辐照前后试样表面形貌和元素组成变化进行了分析.研究表明,在相同能量的电子辐照下,随电子辐照通量的增加,该二次表面镜的表面铟和氧含量减少,碳含量和质量损失增加,其表面导电层被破坏,聚全氟乙丙烯的表面碳化,致使F46镀银二次表面镜光学性能下降.     

典型低轨辐照环境对MoS2-Ti薄膜真空摩擦学性能的影响

采用非平衡磁控溅射方法在9Cr18基底上制备了MoS₂-Ti薄膜，并对4组样品分别进行了电子辐照、电子/质子辐照、电子/质子/紫外辐照、电子/质子/紫外/原子氧辐照。采用SEM、XRD、XPS分析了辐照前后薄膜的结构和化学组成变化，通过摩擦试验考察了辐照前后薄膜的摩擦学性能，探讨了其损伤机制。研究结果表明，电子辐照、质子辐照、紫外辐照对MoS₂-Ti薄膜的显微组织结构、表面形貌及摩擦学性能没有明显影响。动能5 eV的原子氧对MoS₂-Ti薄膜表面有显著的损伤，主要表现在表面出现“绒毯”状形态，Mo、S和Ti元素被氧化成高价氧化物。原子氧辐照导致MoS₂-Ti薄膜摩擦起始和中段摩擦因数升高、中段摩擦因数不稳定，比磨损率增大。     

射频源原子氧暴露对PET薄膜表面性能的影响

采用射频源原子氧装置对PET薄膜材料进行不同时间的暴露试验.研究了氧等离子体暴露对PET薄膜的质量损失、表面形貌、接触角的影响,并对暴露前后PET薄膜进行了红外光谱(FTIR)分析.结果表明,温度随暴露时间延长而升高,达到一定值后趋于平缓;随暴露时间延长PET薄膜的质量损失越来越大,表面形貌变得越来越粗糙,接触角先减小后增大.红外光谱分析表明,氧等离子体暴露后PET薄膜表而O-C=O、C-O等含氧基团的数量有所降低.这是由于原子氧暴露诱导的氧化和表面刻蚀.     

有机硅微胶囊-有机硅树脂复合涂层对空间 K apton的原子氧防护

将采用水相分离法制备的以明胶为囊壁、有机硅为囊芯的微胶囊与有机硅树脂乳液在一定条件下混合,在聚酰亚胺薄膜(Kapton)基材表面制备出含有机硅树脂的微胶囊-有机硅复合涂层,并将所制备的涂层分别进行原子氧暴露试验。结果表明,原子氧对Kapton侵蚀严重,质量损失严重,由原来光滑平整的表面变为凹凸不平的地毯状,太阳光吸收率变化值Δα为0. 272。微胶囊2有机硅复合涂层对Kapton基体优良的保护作用,使试样的质量损失和剥蚀率明显下降,且Δα仅为 0.071。尤其是微胶囊与有机硅质量比为1∶5的涂层,质量损失为Kapton试样的2.3%。     

反应磁控溅射制备的SiO2防护涂层抗原子氧侵蚀性能研究

在原子氧侵蚀地面模拟设备中对Kapton和利用反应磁控溅射制备的SiO2涂层进行了原子氧暴露实验，并采用XPS和SEM等分析手段对暴露前后试样表面的物理和化学变化进行了研究．结果表明，Kapton试样遭受了严重的侵蚀，质量损失较大；SiO2涂层质量变化很小，对基体提供了良好的保护作用．XPS分析结果表明，反应溅射的SiO2涂层是富Si的，初始暴露时由于氧化反应而质量有少许增加，随时间延长，涂层变得完全符合化学计量．SiO2涂层在原子氧暴露后涂层的太阳吸收率、辐射率和反射系数均没有发生明显的变化．SiO2涂层较脆，易产生裂纹，原子氧会通过缺陷位侵蚀下面的基体材料，严重影响飞行任务的正常进行。     

空间级硅橡胶涂层抗原子氧性能及评价机制

文中针对硅橡胶与原子氧的反应机理尚未完全掌握,其防护效果未完全明确的现状,开展原子氧效应地面模拟试验,进行硅橡胶涂层的抗原子氧性能的评价分析。经对试验前后的样品进行外观、质量损失、表观形貌、表面成分及光学性能的测试,系统评价了空间级硅橡胶的原子氧防护效果。在分别接受累积通量为4.9×10~(18) cm~(-2)和1.2×10~(21) cm~(-2)的原子氧暴露试验后,空间级硅橡胶涂层的质量损失并未随原子氧暴露时间延长和累计通量的增加而变大,但涂层表面的外观和光学性能发生了显著变化,经扫描电镜检测,涂层表面出现不同程度的开裂,经X射线光电子能谱仪分析,涂层表面生成了一层类似SiO_2的薄膜,该薄膜层能阻止原子氧与硅橡胶涂层的反应从而对基底材料形成保护,但为了进一步提高其抗原子氧侵蚀能力,需对涂层进行补强改性,并且采用测量质量损失的手段来评判硅橡胶类材料受原子氧侵蚀程度的方法不甚科学。     

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。     

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.     

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.     

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.     

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．     

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.