舒适性和舒适性指标

本文论述了舒适性的含义 ,舒适性的计算和评定指标 ,以及它在房间空调器控制系统设计中的应用     

计量性及计量性设计

从测量的对象分析入手,比较了《计量法》、《国防计量监督管理条例》和《中国人民解放军计量条例》,提出了测量的计量性问题;通过对美军标MIL-STD-1839D《美国国防部校准和测量要求》的分析,为确保系统运行的一致性和准确性,提出了必须开展计量性设计的研究工作;最后,基于系统、便捷、快速的计量保障保证系统始终处于良好技术状态的前提下,提出了计量性设计方法和设计原则。     

即时存在性和生长性在交互设计中的解读

目的提出并阐述即时存在性和生长性的概念并对二者特性进行解读。方法指出交互设计的根本要素是变动性,即时存在性和生长性是其外在的体现。分析了即时存在性和生长性的特性及其在交互设计中的价值,进而论述了两种特性的应用原则。结论即时存在性和生长性的应用有助于增强交互过程中的灵活性和创新性,增进用户与产品人机关系的和谐,这里旨在为交互设计的实现提供新的思路与方法。     

HDPE的耐磨蚀性与抗冲击性的研究

用自制的旋臂式磨蚀实验仪，研究了５种高密度聚乙烯和１种顺丁橡胶改性的高密度聚乙烯，在铁尾矿和铁精矿浆体中的耐磨蚀性。耐磨蚀性最差的是ＨＤＰＥ２２００Ｊ，耐磨蚀性较差的是ＨＤＰＥ６３００Ｍ；ＨＤＰＥ５０００ｓ，６０９８和２４８０的耐磨蚀性较好；ＨＤＰＥ／ｃｉｓ－ＢＲ的耐磨蚀性最好。     

英汉翻译中的可译性与可译性限度

本文从语言和文化两方面简要阐述了汉英翻译中可译性和可译性限度的问题。     

L-Fuzzy拓扑空间中的F仿紧性和F强仿紧性

仿紧性是经典拓扑中的一个重要概念。如何合理定义LF拓扑空间中的仿紧性是一引人注目的课题。在文[3]中作者讨论了LF拓扑中的仿紧性和强仿紧性。由于LF拓扑空间的层次性,相应地引入F仿紧性和F强仿紧性。可以看到,仿紧性和强仿紧性所具有的主要性质,F仿紧性和F强仿紧性也相应地具有。     

粘附性具有可控响应性的智能超疏水表面研究进展

具有特殊粘附性的超疏水表面因其广阔的应用前景而引起人们的极大关注。讨论了表面形貌和表面化学组成对超疏水表面粘附性的影响及超疏水表面粘附性的评价标准,综述了近年来粘附性具有可控响应性的超疏水表面的研究进展,并对超疏水表面粘附性的研究进行了总结和展望。     

武器装备测试性设计探讨

在研制武器装备时,要同时考虑装备的测试性设计和研制测试设备.针对现役武器系统测试性存在的问题,本文对测试性设计的必要性和测试性设计的方法等问题提出若干看法和设想.     

一类细胞神经网络概周期解的存在性与吸引性

本文研究各细胞元拥有各自信号处理函数并具分布时滞的变系数二维分流抑制细胞神经网络的概周期解的存在性和吸引性,获得存在性与吸引性的一个充分条件。     

脉冲时滞积分-微分系统解的非振动性和渐近性

讨论了脉冲时滞积分-微分系统解的非振动性和渐近性，得到了时滞积分-微分系统在脉冲扰动下解的非振动性和渐近性的充分条件。     

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。     

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.     

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。     

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.