高聚物的超声波合成研究进展

综述了高分子材料的超声波合成最近的研究成果，评述了超声波在聚合合成中的作用机理及聚合物的超声波合成条件。     

渗透型丙烯酸树脂的合成与表征

报道了渗透型丙烯酸树脂的合成过程与结构表征，探讨了合成反应中影响产率的因素。对所合成丙烯酸树脂的粘度、玻璃化温度（Ｔｇ）等物理性能与Ｅｕｄｒａｇｉｔ ＲＳ进行了对比研究，证明该合成路线是可行的。     

含硅双马来酰亚胺的合成及表征

采用新的合成路线制得了Ｎ－（４－羟基苯基）马来酰亚胺，并以此为起始反应物合成了３种新型含硅双马来酰亚胺。所合成的含硅双马来酰亚胺的分子结构采用红外光谱及＾１Ｈ－ＮＭＲ进行了表征。     

不饱和体系光聚合动态过程的研究

合成了多种单体和不饱和体系。采用ＤＳＣ法系统的研究了关助剂，促进剂，链转移剂和各种单体以及安息香双甲醚的浓度等对于不饱和体系的ＵＶ聚合成和感光性能的影响。     

苯乙烯—二乙烯基苯与甲基丙烯酸接枝聚合的研究

合成了具有悬吊双键的苯乙烯－二乙烯基苯的功能微球，在悬吊双键外接枝甲基丙烯酸，制成了一系列不同接枝度的两亲性聚合物，并将其拉制成ＬＢ膜，这种膜具有良好的Ｃ－Ｖ特性。     

两亲性高聚物及其应用

两亲性高聚物在生物材料,高分子加工的助剂,药物载体,乳液分散剂,黏合剂,涂料等方面存在 广泛的应用。综述了不同种类两亲性高聚物的合成,应用及发展。     

聚合物载体钛催化剂下的乙烯聚合

分别以聚和聚为载体，合成了两类聚合物载体钛系催化剂利用红外光普，Ｘ射线电子能谱分析了载体民ＴｉＣｌ４的结合方式，并进行了两种催化剂下乙烯聚合的研究。     

SJ—06水基成膜防锈剂的研制

设计并合成了水基成膜防锈剂ＳＪ－０６，对钢的防锈能力；室内挂片３个月以上，聚忆烯膜包封防锈期１年以上，膜层易去除。     

液晶杂环高聚物的合成

首次较详细地论述了聚苯撑苯并二噻唑或二咪唑（ＰＢＴ或ＰＢＯ或ＰＢＩ）、聚苯并噻唑或恶唑（ＡＢＰＰＢＴ或ＡＢＰＢＯ）、聚苯并二咪唑苯并菲绕啉二酮（ＰＱ）及其衍生物的合成方法和相应的特性粘数。     

新型高效膨胀阻燃炭化剂的研究

本文合成并用红外、元素分析等手段表生了两种新的含氟大分子化合物Ａ、Ｂ，用作聚丙烯（ＰＰ）膨胀阻燃剂ＰＰＮ的炭化剂，研究了Ａ、Ｂ的热稳定性、ＰＰＮ与Ａ、Ｂ添加比例、ＰＰＮ／Ａ（Ｂ）的添加量对阻燃性能的影响，并用扫描电镜（ＳＥＭ）研究了用该阻燃剂处理过的ＰＰ燃烧形成的炭层结构。研究结果表明合成的炭化剂Ａ（Ｂ）：ＰＰＮ９＝２：１３时阻燃效果最好，和ＰＰＮ９结合，对ＰＰ上有极佳的阻燃性能。     

GLONASS时间频率传递研究

分析了基于GNSS的时间频率传递方法的发展趋势和GLONASS发展现状及趋势。对GLONASS时间频率传递进行了研究,就其原理实现、误差补偿及数据处理进行了阐述,实现了GLONASS时间频率传递的基本方法,实施了GLONASS和GPS时间频率传递实验。将两种时间频率传递结果进行了对比,对GLONASS时间频率传递自身性能进行了分析,结果显示:GLONASS时间频率传递已达到了可与GPS时间频率传递相比较的水平。     

芦荟甙和芦荟大黄素的提取和同时测定

本文研究芦荟甙和芦荟大黄素的提取和同时测定。方法:以无水乙醇为萃取剂,从芦荟叶片和渗出汁液中提取芦荟甙和芦荟大黄素;采用分光光度法,同时测定芦荟甙和芦荟大黄素含量,测定波长分别为360nm和440nm.结果:从芦荟汁液和芦荟叶片中提取得到芦荟甙和芦荟大黄素的含量分别为39.0％、3.47％和1.39％、0.814％.回收率为98.0～102.1％、97.0～101.5％.结论:芦荟汁中芦荟甙和芦荟大黄素含量较高,本文提出分光光度法同时测定芦荟甙和芦荟大黄素含量,方法简便,快速、准确。     

The Influence of Austempering Conditions on the Machinability of a Ductile Iron

Austempering conditions such as temperature and time and their influence on austempered ductile iron machinability were analyzed. Austenitization at 910°C for 90 min and austempering into molten salt bath at 300°C, 360°C, and 420°C for 30, 60, and 90 min each were performed. Microstructures were analyzed by optical microscopy and hardness measurements. Samples were further machined in a lathe for machinability tests. The lathe was instrumented considering power and cutting time and machinability evaluation performed referring to cutting force and material removal. Microstructures at 300°C for 30 min showed ausferrite with retained austenite and martensite. Retained austenite decreased and acicular ferrite sheaves appeared at 60-min austempering time. Mixed bainite was also present at 90-min austempering. Ausferrite and retained austenite were observed in all austempering periods at 360°C, whereas at 420°C only bainite and fine pearlite were present. Hardness increased with increasing temperature at 30-min austempering and decreased with increasing time. However, an exception was observed at 420°C. The highest machinability performance was achieved at 360°C at 60-min austempering, and the lowest performance at 420°C at 90-min austempering.     

Engineering Materials for Neurotechnology

Neurotechnology applies methods and devices to mitigate the burden of neurological and mental disorders. In particular, neural interfaces establish a long-term, seamless, symbiotic integration between implants and neural tissue. Materials play a pivotal role in neurotechnology. Advanced materials and materials engineering are crucial to achieving the desired function and outcome. Recently, neural interfaces extended their range of applications with the emergence of flexible, conformable, stretchable, injectable, and transient electronics. However, despite this enormous advancement in materials science and engineering, clinical devices still rely on old-fashioned but reliable materials and processes. The gap between research development and industry adoption has recently gained high interest. This article analyzes recent developments, discusses roadblocks, and provides a roadmap for materials engineering applied to neurotechnology.     

A novel special distributed method for dynamic refrigeration system simulation

A novel dynamic mathematical model based on spatially distributed approach has been developed and validated in this paper. This model gives good agreement in predicting the system COP and other parameters. The validated model has been used to enhance the prediction of the micro variations of superheat and sub-cooling. The novel spatial distributed model for the condenser and evaporator in refrigeration system, calculates the two-phase region in gas and liquid field separately since the gas and liquid in the two-phase region have different velocities. Previous researchers have used a pre-defined function of the void fraction in their spatially distributed model, based on experimental results. This approach results in the separate solution of the mass and energy equations, and less calculation is required. However, it is recognized that the mass and energy equations should be coupled during solving for more accurate solution. Based on the energy and mass balance, the spatial distribution model constructed here solves the velocity, pressure, refrigerant temperature, and wall temperature functions in heat exchangers simultaneously. A novel iteration method is developed and reduces the intensive calculations required. Furthermore, the condenser and evaporator models have shown a parametric distribution along the heat exchanger surface, therefore, the spatial distribution parameters in the two heat exchangers can be visualised numerically with a two-phase moving interface clearly shown.     

Technik und Potenziale des Verschleißschutzes mittels thermisch gespritzter Beschichtungen

Technology and Potential of Wear Resistant Thermal Spray Coatings Thermal spray technologies are used for coating of component parts with a large variety of materials, e. g. for protection against wear and corrosion. During the last 20 years, the comparatively novel processes in thermal spraying have been established in surface technologies and will increasingly develop their market. Continuous equipment developments as well as new technologies for thermal spraying guarantee increasing importance of this technology, and will have a sustainable effect on industries with typical wear and corrosion‐caused problems. Therefore, thermal spray coated components possess an outstanding suitability and a high application potential for the construction of stone machining machines / plants and the mining industry (as well as associated vehicle and equipment technology), which still has hardly been developed in the area of mining industry and stone machining. A short introduction of thermal spray technology and processes and an overview is given for typical applications and already established coating solutions besides some recent examples from the area of stone machining and mining. This article shows the potential of thermally sprayed coatings as solutions for the stone machining and mining industry.     

Entwicklung des Reibnietens als neues Fügeverfahren für Kunststoff und Leichtbaulegierungen

Development of FricRiveting as a new joining technique for polymer and lightweight alloys The increasing demand on environmental consciousness, cost savings and high performance end products has been guiding scientists and engineers to a constant development of new materials and technologies. This class of lightweight structures are specially used in industrial fields such as transportation and modern civil engineering. Currently available joining methods for polymer‐metal structures (adhesive bonding and mechanical fastening) are usually application‐specific, presenting high operational costs, limited mechanical performance or are not environmental friendly. A new Friction Riveting technique for polymeric‐metallic joints was developed, demonstrated and characterized in this work, as an alternative, reliable, environmental compatible and economically viable spot joining process. In the simplest process variant a rotating cylindrical metallic rivet is inserted in one or more thermoplastic base plates. The high rotation speed and pressure increase friction and heat is generated. When the preset time is achieved the temperature highly increases and the rivet tip plasticizes. At this point rotation is decelerated and the axial pressure increased, so the plasticized rivet tip becomes deformed; after cooling it becomes anchored in the polymeric base plate. In this work case‐study joints on commercially available polyetherimide (PEI) and aluminium 2024‐T351 (Al‐Cu‐Mg alloy) were chosen for demonstrating proposed theories and mechanisms of FricRiveting. Sound friction riveted point‐on‐plate and single‐rivet overlap joints with elevated joint efficiencies in terms of base materials strength were obtained (tensile joint efficiencies of about 97 % of the rivet strength and shear joint efficiencies of about 70 % of the polymer strength) through tensile and lap shear testing at room temperature. Finally, the microstructural changes and properties were described for this case‐study joint. The feasibility of FricRiveting was demonstrated in this work by the presented technical and scientific results. From this work it can be suggested that FricRiveting has the potential to be established as a reliable, simple, cost effective and environmental friendly joining technique for polymer‐metal components.     

Modeling of frost growth and frost properties with airflow over a flat plate

A physical model of frost layer growth and frost properties with airflow over a flat plate at subfreezing temperature was developed. Frost roughness was measured, and an empirical correlation for the average frost roughness was suggested. Heat and mass transfer coefficients were calculated using the modified Prandtl mixing-length scheme containing the effects of both frost roughness and turbulent boundary layer thickness. Frost thermal conductivity was theoretically analyzed by solving the combined equations of air equivalent conductivity and thermal conductivity of the frost inner layer. Based on the present model, heat and mass transfer coefficient, frost thermal conductivity, frost thickness, frost mass concentration and frost density with time and space were estimated. The model showed good agreement with the basic trends of the test data taken from other literature. Spatial and temporal changes of heat flux and frost surface temperature were also investigated.     

Effect of Dy and Nd on ZK10 alloy processed by hot extrusion

About 0.6%Dy and 0.2%Nd are simultaneously added to ZK10 alloy processed by hot extrusion, and their effects are investigated. Obvious refined grains and weakened texture are observed after addition of Dy and Nd. Significantly improved mechanical performance with increase of 16% in yield strength and of 114% in ductility is obtained compared with ZK10 alloy. The strengthening effect is attributed to the grain refinement and solid solution, and the enhanced ductility results from the refined structure and weakened texture. Better optimization in mechanical performance with enhanced strengthening is generated, compared with the alloy with individual RE element addition. Combined addition of trace Dy and Nd throws light on the wide-range production and application of extruded ZK10 alloy.     

Influence of Processing Temperatures on Mechanical Properties and Microstructure of Squeeze Cast Aluminum Alloy Composites

The paper deals with the influence of melt and die temperatures on the squeeze cast silicon carbide particulate reinforced aluminum alloy composites. Samples were produced at the following constant melt and die temperatures: melt—750, 800, 850, and 900°C; die—250, 300, 350, and 400°C. During the specimen fabrication, pressure was maintained at 100 MPa. The results reveal significant influence of both melt and die temperatures on the mechanical properties. The optimum melt and die temperatures for the preparation of the composite are 850°C and 350 °C, respectively. Tensile and impact strengths, and hardness of composite samples prepared at this temperature combination are found to be better than those of samples prepared at other temperatures. Additionally, microstructures of samples prepared at this temperature combination display a relatively fine grain structure and the smallest degree of particle agglomeration which explain the dependence of mechanical properties on the melt and die temperatures.