纳米铜改性酚醛树脂及其应用性能

采用新发明的原位生成法成功地制备了摩擦材料用纳米铜改性酚醛树脂。利用XRD和TEM对所制备的树脂进行了表征。结果显示,纳米铜的粒径为10~40 nm,呈近球形。进行了TGA、冲击试验和摩擦试验。结果表明,纳米铜改性酚醛树脂的耐热性有较大提高,与纯酚醛树脂相比,其初始分解温度和半分解温度可分别提高31℃和46℃;纳米铜改性酚醛树脂基摩擦材料的韧性和摩擦学性能有明显改善,与纯酚醛树脂基摩擦材料相比,冲击强度提高44%,热衰退率和磨损率分别降低约50%和2/3。建立了酚醛树脂/纳米铜复合材料的界面模型,并探讨了纳米铜改善酚醛树脂及摩擦材料性能的机理。      

有机蒙脱土改性R-122环氧树脂纳米复合材料的制备与性能

以钠基蒙脱土(Na-MMT)为原料,十六烷基三甲基溴化铵(CTAB)为插层剂,成功地制备出有机蒙脱土(OMMT),对其结构分析表明:蒙脱土的层间距由1.43nm增加到1.925～3.85nm。用该有机蒙脱土对R-122进行改性,成功制备了R-122复合材料,当有机蒙脱土的在树脂中添加的质量分数为4.0%时,冲击强度达到最大值21.2J/m,比纯树脂的提高了92.7%;扫描电镜分析表明:复合材料的断口呈复杂的层状分布,说明复合材料形成的新表面多,吸收的冲击能多;差示扫描热量分析表明,蒙脱土的加入使环氧树脂的耐热性得到进一步提高。利用有机蒙脱土对R-122树脂改性同时提高了韧性和耐热性,为R-122基高性能复合材料的制备提供了新的途径。     

共混条件对功能化聚异丁烯-蒙脱土复合物改性聚丙烯性能的影响

制备了功能化聚异丁烯-蒙脱土复合物改性的聚丙烯复合材料。考察了活化剂、加工温度等因素对改性聚丙烯性能的影响。通过扫描电镜观察了蒙脱土在改性聚丙烯中的分散效果。实验结果表明,功能化聚异丁烯-蒙脱土复合物可以较好地分散在聚丙烯中,当其用量为4wt%、活化剂用量为蒙脱土的1wt%时,制备的聚异丁烯-蒙脱土/聚丙烯复合材料的模量为2280 MPa、冲击强度为63J/m,回缩率为0.5%,各项指标均好于未改性的聚丙烯树脂。分散在聚丙烯中的蒙脱土尺寸约为1μm。     

黄金分割原则在酚醛树脂基摩擦材料配方设计中的应用

在酚醛树脂基摩擦材料配方设计中,采用黄金分割原则对增强纤维的含量进行优化。通过对摩擦材料样品进行摩擦磨损性能、力学性能和物理性能测试,结果表明,当碳纤维质量含量为16%,矿物纤维质量含量为5%时,摩擦材料样品的综合性能最佳,其摩擦系数值为0.40,磨损率为0.26×10~(-7)cm~3/N·m,冲击强度为5.21J/cm~2,硬度为85HRM,密度为1.88g/cm~3。表明利用黄金分割原则设计摩擦材料的配方在大幅减少实验次数的同时,可以显著改善摩擦材料的性能。     

钛酸钾晶须-玻璃纤维/苯并噁嗪混杂复合材料的摩擦磨损性能

利用六钛酸钾晶须（K₂O·6TiO₂）对苯并噁嗪（BOZ）树脂及玻璃纤维/苯并噁嗪（GF/BOZ）复合材料的摩擦磨损性能进行改性,分析了K₂O·6TiO₂/BOZ复合材料以及K₂O·6TiO₂-GF/BOZ混杂复合材料的摩擦磨损性能以及改性机理。结果表明:因K₂O·6TiO₂的加入,K₂O·6TiO₂/BOZ复合材料以及K₂O·6TiO₂-GF/BOZ混杂复合材料的摩擦系数和比磨损率较纯BOZ树脂和GF/BOZ复合材料的明显降低。K₂O·6TiO₂显著减轻了BOZ树脂和GF/BOZ复合材料的摩擦粘着状况,使摩擦系数降低,同时磨粒磨损情况也大为减轻。GF/BOZ复合材料在摩擦过程中摩擦应力通过率先破坏GF和BOZ树脂的界面,进而诱发破坏GF束内、GF束间和层间BOZ树脂,使得GF/BOZ复合材料的摩擦系数比BOZ树脂降低,但比磨损率较BOZ树脂升高,而K₂O·6TiO₂的加入,使K₂O·6TiO₂-GF/BOZ混杂复合材料的比磨损率有效降低。BOZ树脂、GF/BOZ、K₂O·6TiO₂-GF/BOZ 3种材料的摩擦系数和比磨损率分别为0.34和0.66×10-6 mm3·（N·m）-1,0.19和1.2×10-6 mm3·（N·m）-1,0.09和0.69×10-6 mm3·（N·m）-1。      

钛酸钾晶须改性酚醛树脂基摩擦材料的性能研究

采用干法热压成型工艺制备了钛酸钾晶须增强的酚醛树脂基摩擦材料,研究了晶须含量对摩擦材料样品摩擦性能、磨损性能、物理性能和机械性能的影响,结果表明,适量的钛酸钾晶须添加有助于改善材料的摩擦磨损性能和力学性能,当钛酸钾晶须质量含量为4%时,摩擦制品的摩擦系数μ=0.40,磨损率为0.12×10~(-7)cm~3/N·m,冲击强度和硬度分别为4.15kJ/m~2和74HRM,密度为2.15g/cm~3,符合GB 5763—2008的第3类标准。     

热致性液晶/氧化石墨烯/酚醛树脂复合材料的力学性能与摩擦性能研究

将酰氯化后的氧化石墨烯与热致性液晶聚合物经溶液混合法制备热致性液晶聚合物/氧化石墨烯(TLCP/GO)混杂材料;通过辊炼、挤出、模压成型工艺制备热致性液晶聚合物/氧化石墨烯/酚醛树脂(TLCP/GO/PF)复合材料,研究TLCP/GO混杂材料含量对酚醛树脂复合材料的力学、动态力学及摩擦性能的影响。结果表明:添加量为0.5%时复合材料的弯曲强度及弯曲模量分别提高了26%及11%;添加量为0.5%时,复合材料初始储能模量提高了31.5%,同时,混杂材料的加入一定程度上改善了复合材料的摩擦磨损性能,其中混杂材料添加量为0.5%时,复合材料的摩擦系数在0.39~0.28之间,250℃时,复合材料的磨损率为0.39×10-7cm3/N·m,比纯酚醛复合材料降低48.7%,表明TLCP与GO具有协同增强作用。     

纳米粒子对丁腈改性酚醛树脂摩擦磨损性能的影响

采用Al2O3、TiO2、SiO2、SiC四种纳米粒子以及不同百分含量改性丁腈改性酚醛树脂,利用机械共混的方法制备了纳米粒子改性丁腈改性酚醛树脂材料。通过热失重分析表明,A3和T5的耐热性得到了提高,在高温阶段A3又高于T5,说明A3的耐热性最好。摩擦磨损对比试验表明,Al2O3、TiO2纳米粒子可显著提高改性丁腈酚醛树脂的耐热性、增加摩擦系数、降低磨损率;SiO2、SiC纳米粒子对树脂的摩擦磨损性能没有明显改善。     

摩擦材料用酚醛树脂改性研究进展

综述了近年来摩擦材料用酚醛树脂增韧、增强以及耐热改性的研究进展。分析比较了橡胶、植物油、无机纳米材料、纤维以及聚苯并噁嗪树脂等改性体系对酚醛树脂基摩擦材料性能的影响。纳米粉末橡胶可同时提高酚醛树脂的耐热性和韧性,弥补了传统橡胶改性的不足;植物油可提高酚醛树脂的韧性,但也会使其的耐热性下降;无机纳米粒子的团聚问题影响其改性效果;纤维对酚醛树脂有增强增韧作用外,还可以明显改善其摩擦性能;而天然纤维可再生、价廉,而且强度高,但作为摩擦材料增强体,其耐热性有待改善;新型热固性酚醛树脂固化温度较高,要取代传统酚醛树脂还须进一步深入研究。     

坡缕石纳米份数对原位复合的PF及其摩擦材料性能的影响

分别在预聚物体系中添加质量份数为0.3%,0.7%,1.0%,1.3%.的坡缕石纳米(称为P纳米),原位合成坡缕石/桐油酚醛树脂(P/TPF).用TEM观察纳米粒子在树脂中的分散状况,用SETARAM TG-DSC92-16热分析仪对合成的树脂进行了TG分析;将所合成的树脂分别制作成编织摩擦材料并在DMS-1试验机上对其摩擦学性能进行测试.结果表明:P纳米份数在0.3%.～1.0%.范围内P/TPF热失重率在240～600℃的中温区近于线性递减;当P纳米份数为1.0%.时树脂的耐热性及其摩擦材料综合性能最佳,抗热衰温度可达280℃,200℃耐磨性最好,磨损率比无纳米桐油酚醛树脂摩擦材料提高15%..     

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.