金属零件表面感应热处理

本文根据金属材料感应加热的特点,叙述了表面感应热处理的物理过程;并经分析提出了感应热处理工艺参数具体计算选择的方法。为充分发挥金属零件表面感应热处理独特的优点,使热处理工艺规范合理化,提供应用和参考。     

汽车舱边梁后段钢板的工艺优化

针对汽车舱边梁高强度钢板在板料成形时存在的诸多问题,介绍了高强度钢板成形原理,并针对某款汽车舱边梁后段采用高强度钢板时存在的回弹问题,建立了结构模型和数学模型。对三种高强度材料零件的冲压工序进行了仿真分析,从而选择了HC500-780DP型号钢材。借助AutoForm软件对所选择的钢材进行工艺分析和动态仿真,通过改变拉延筋参数,将高强度钢板零件的最大减薄率控制在12.5%,以符合工艺要求。最后,将仿真结果与实际工序相结合,在拉延工序中增加了工艺鼓包,使得高强度钢板的工艺性能得到优化。     

渐开线花键工艺参数的设计

￥中国轻骑集团青岛鸿达厂＠孙成勤＠刘金钊１前言渐开线花键的优点是定心好、受力均匀、强度高、寿命长，因而应用十分广泛。在摩托车中许多零件就有渐开线花键。其中外花键的制造方法主要有滚刀切削法和冷挤压成形法。本文简要介绍在外花键冷挤压成形法的加工工艺参数的设计中...     

CAPP系统“工艺装备选择方法”的研究与开发

工艺装备的采用是保证零件加工质量、提高劳动生产率的有效手段之一。工艺装备的正确选择,是工艺设计人员进行工艺设计的主要任务,也是工艺设计的成败的关键。本文以成组技术为前提,以装配关系为基础,以零件的信息编码作为主约束条件通过对零件的各结构元素与相关件的装配关系以及零件和工装的“改进轨迹“的研究确定CAPP系统中工艺装备选择的约束条件和工作流程,从而使CAPP系统完成相近工装列表甚至自动选择适用的工装,同时对现有工装的不适应处进行标记。     

CAPP系统"工艺装备选择方法"的研究与开发

工艺装备的采用是保证零件加工质量、提高劳动生产率的有效手段之一.工艺装备的正确选择,是工艺设计人员进行工艺设计的主要任务,也是工艺设计的成败的关键.本文以成组技术为前提,以装配关系为基础,以零件的信息编码作为主约束条件通过对零件的各结构元素与相关件的装配关系以及零件和工装的"改进轨迹"的研究确定CAPP系统中工艺装备选择的约束条件和工作流程,从而使CAPP系统完成相近工装列表甚至自动选择适用的工装,同时对现有工装的不适应处进行标记.     

MIM零件连续烧结设备现状及发展目标

通过对MIM成形工艺过程的分析、以及粉末注射成形零件的特点,论述应将传统脱脂、烧结乃至后处理等单一工序融合为综合工序的必要性,并勾画了连续烧结设备的结构与控制模式的发展目标。     

电炉用特种金属切削性能的分析及刀具选择

本文对电炉常用的几种特殊金属材料的机械性能和物理性能以及它们在切削加工过程中出现的各种现象进行了分析。 根据这些材料的加工复杂性能,介绍了切削加工的刀具材料和刀具几何角度的选择。电炉行业在现有的机床设备条件下,如果采用这些刀具材料和几何角度,不但能解决切削加工难的问题,而且能使每只零件达到原设计的精度要求。     

MS6001B型燃气轮机导流板拉弯成形的工艺研究

根据导流板零件的特点,试选用拉弯成形的方法进行加工。为此对导流板拉弯成形过程的应力和应变进行了较细致的分析,推导出了有关的计算公式。根据分析,制定了合理的工艺方案,制出了合格的产品。     

隔板计算机辅助工艺设计

本系统是东方汽轮机厂汽轮机隔板的计算机辅助工艺设计的实用系统，着重讨论了隔板的计算机辅助工艺设计的方法，基本解决了零件信息的描述与输入、工艺数据的处理、数据的传输、工艺文件的输出等问题，实现了隔板的计算机辅助工艺设计，为进一步在工艺设计中应有和计算机打下了一定基础。     

工业型煤炉前无粘结剂成形性的试验研究

本文就工业型煤炉前成形工艺，研究了烟煤、无烟煤在无粘结剂状态下的冷压成形性，得出煤物性与煤成形性的关系，即水分、粒度、成形压力对型煤强度、密度的影响。为工业锅炉燃烧型煤以及成形装置的设计提供了技术依据     

A review of performance optimization of MOF‐derived metal oxide as electrode materials for supercapacitors

Metal‐organic frameworks (MOFs), as new class of porous materials, are constructed by inorganic metal centers and bridging organic links. Recently, MOFs have been proved to be effective templates for preparing metal oxides with large surface areas and controlled shape by directly annealing in air. There are lots of reports about metal‐organic framework‐derived metal oxides as electrode materials for supercapacitors. Metal‐organic framework‐derived metal oxides can offer higher capacitances compared with that prepared by other synthetic methods, likely attribute to high surface areas and optimal pore sizes. However, at present, the specific capacitances of MOF‐derived metal oxides received are far lower than theoretical values, and the cycle numbers could not meet practical demands. Accordingly, much effort has been made to improve the performance by further modifying MOFs. Thus, this paper focused on the advances in performance optimization of MOF‐derived metal oxide as electrode materials for supercapacitors as follows:

1. Dual metal MOF‐derived binary metal oxides. Metal oxides with 2 metal cations possess better electrical conductivity and richer redox active sites than single metal oxides.
2. Metal‐organic framework‐derived carbon/metal oxide composites (MO@C) or graphene/MOF‐derived graphene/metal oxide composites. Doping carbon not only facilitate transportation of electrodes but also contribution to extra double‐layer capacitance.
3. Hybrid MOF‐derived metal oxide composites (MO@MO). Metal oxide composites can produce some synergistic effects that the individuals cannot provide.
4. Metal‐organic framework‐derived metal oxides with a hollow structure. The Hollow structure could shorten ion diffusion distance and adapt to volume expansion generated during the ion intercalated/extracted process.

     

纳米金属及氧化物对污染处理的影响研究进展

纳米金属及氧化物在日常生活中应用广泛,它们会通过各种途径进入环境,因此需要对它们的环境和健康风险进行评估。纳米金属及氧化物具有独特的物理化学性质。综述了纳米金属及氧化物对污染去除过程中微生物的毒性方面的文献,特别关注了其对污染处理过程(污水处理、固体废弃物处理)的影响,并阐述了可能的毒性机制。在此基础上,探讨了纳米金属及氧化物的微生物毒性的研究目前存在的问题和未来研究的展望。     

Control of metal dusting corrosion in Ni-based alloys

Metal dusting is a major issue in plants used in the production of hydrogen-and methanol-reformer systems, and syngas (H₂/CO mixtures) systems that are pertinent to the chemical and petrochemical industries. Usually, metal dusting corrosion has two stages: incubation and growth resulting in propagation of metal dusting pits. The two stages were studied by scanning electron microscopy and profile mapping to evaluate the scale of the surface oxide in the initiation and propagation of metal dusting attack. The initiation occurs because of the presence of defects, and the propagation is determined by the diffusion of carbon into the alloy. The carbon diffusion pathways can be blocked by periodically oxidizing alloy surface at moderate temperatures in controlled atmospheres. It was concluded that metal dusting degradation can be mitigated by selecting an alloy with a long incubation time and subjecting it to intermediate oxidation.     

Investigation on the influences of heat transfer enhancement measures in a thermally driven metal hydride heat pump

Metal hydride heat pump (MHHP) can be utilized in a variety of applications and shows great potential in recovery of low-grade heat. Being its kernel component, the reactors should facilitate good heat and mass transfer to achieve satisfactory system performance. In this paper, the influences of certain heat transfer enhancement measures for the reactors were investigated by numerical simulation and thermodynamic analysis. Three types of reactors packed with metal hydride powder, metal hydride powder/Al foam and metal hydride compact were taken for discussion. As shown in the simulation results, for the MHHP adopting heat transfer enhancement, the coefficient of performance tends to reduce slightly while the specific heating power increases remarkably. Therefore, these measures work positively and are recommended for use in heat pump applications.     

Influence of intrinsic hydrogenation/dehydrogenation kinetics on the dynamic behaviour of metal hydrides: A semi-empirical model and its verification

Metal hydrides can store hydrogen at low pressures and with high volumetric capacity. For the possible application as storage medium in hydrogen stand-alone power systems, large metal hydride hydrogen storage units are usually required. A reliable and verified kinetic correlation is an important tool in the designing process of a larger storage unit. This paper describes kinetic investigation of a AB₅-type alloy and its corresponding hydride, with the purpose of finding a semi-empirical correlation suitable for use in heat and mass transfer modelling and engineering design of metal hydride storage units.     

金属泡沫平板结构内对流换热的数值研究

基于Brinkman-Darcy模型和两方程模型,本文对流体在金属泡沫平板通道内的强制对流换热进行了自编程数值模拟,采用体积平均法对流体在金属泡沫内的流动和换热进行宏观处理。模拟结果表明：流体主流速度随孔密度增大而减小,随孔隙率增大而增大;流体相和固体相之间的局部对流换热系数随孔隙率和孔密度增加而增加,金属泡沫对流换热性能随孔隙率增大而减小,随孔密度增大而增大。金属泡沫强化换热的效果十分明显,可以应用于需要强化换热的紧凑式换热器和散热器。     

Future perspectives of thermal energy storage with metal hydrides

Thermochemical energy storage materials have advantage of much higher energy densities compared to latent or sensible heat storage materials. Metal hydrides show good reversibility and cycling stability combined with high enthalpies. They can be used for short and long-term heat storage applications and can increase the overall flexibility and efficiency of solar thermal energy production. Metal hydrides with working temperatures less than 500 °C were in the focus of research and development over the last years. For the new generation of solar thermal energy plants new hydrides materials with working temperatures above 600 °C must be developed and characterized. In addition to thorough research on new metal hydrides, the construction and engineering of heat storage systems at these high temperatures are challenging. Corrosion problems, hydrogen embrittlement and selection of heat transfer fluids are significant topics for future research activities.     

In-situ activation of hydrogen evolution in pH-neutral electrolytes by additions of multivalent cations

Activation of the hydrogen evolution reaction (HER) in close to pH-neutral electrolytes can be achieved by addition of trivalent cations. This activation has been investigated using steady state polarization, electrochemical impedance spectroscopy (EIS) and chemical analysis of cathode films for yttrium. Several multivalent cations were included in this study, such as Al(III), Mg(II), Y(III), Sm(III), La(III) and Sc(III). In general the more acidic the metal ions the larger is the activation. Metal hydroxide films formed in the alkaline diffusion layer at the cathode surface can have a negative impact on the magnitude of this activation, and therefore complicate the interpretation of the results. The activation corresponds to a transport of metal ion complexes to the electrode surface and the reduction of bound ligand water to form hydrogen.     

A Review of Metal Foam and Metal Matrix Composites for Heat Exchangers and Heat Sinks

Recent advances in manufacturing methods open the possibility for broader use of metal foams and metal matrix composites (MMCs) for heat exchangers, and these materials can have tailored material properties. Metal foams in particular combine a number of interesting properties from a heat exchanger's point of view. In this paper, the material properties of metal foams and MMCs are surveyed, and the current state of the art is reviewed for heat exchanger applications. Four different applications are considered: liquid–liquid, liquid–gas, and gas–gas heat exchangers and heat sinks. Manufacturing and implementation issues are identified and discussed, and it is concluded that these materials hold promise both for heat exchangers and heat sinks, but that some key issues still need to be solved before broad-scale application is possible.     

Metal oxide applications in organic-based photovoltaics

Abstract

Organic-based photovoltaics (PV) have attracted increasing attention in recent years and efficiencies exceeding 8% have recently been confirmed. These low cost, lightweight and mechanically flexible devices offer unique advantages and opportunities currently unavailable with crystalline silicon technology. Progress in the field of organic PV has been achieved in part due to the incorporation of transition metal oxides. These offer a wide range of optical and electronic properties, making them applicable in organic-based PV in many capacities. Transparent electrodes can be made from doped metal oxides. The high intrinsic charge carrier mobility of many undoped metal oxides makes them attractive as active materials and charge collectors. Metal oxides can increase the charge selectivity of the electrodes due to the energetic positioning of their valence and conduction bands. Thin films of these materials can manipulate the light distribution inside of organic devices, allowing for improved light harvesting. Metal oxides are stable and can be processed at low temperatures. Consequently, they have been demonstrated as suitable intermediate layer materials in tandem cells. Finally, oxygen-deficient metal oxides can improve the stability of the oxygen- sensitive organic semiconductors. The present work reviews the various applications of metal oxide layers in organic PV devices and summarises the challenges associated with organic/oxide interfaces.