7050铝合金板材深冷处理时温度场的数值模拟

基于实验测定的7050铝合金试件深冷处理的中心温度曲线,运用反传热法计算了试件深冷处理时的表面换热系数;应用有限元分析软件ANSYS计算了7050铝合金深冷处理时的温度场。研究表明7050铝合金深冷处理时的温度场与传热是非线性的,中心温度曲线的计算结果和实验结果比较吻合。     

深冷处理工艺对W6Mo5Cr4V2钢力学性能和微观组织的影响

采用正交实验设计的方法对W6Mo5Cr4V2高速钢循环深冷处理工艺进行了实验研究,分析不同深冷工艺参数对宏观力学性能的影响,使用SEM和TEM观察循环深冷处理断口形貌和微观组织.结果表明,采用循环深冷处理工艺后,随着深冷次数的增加,力学性能明显提高,沿马氏体位错网析出大量超细弥散分布的碳化物数量增多,尺寸和间距减小,与一次长时间深冷处理相比,循环深冷处理效果更好.     

深冷处理对高碳高合金工具钢SDC99回火过程碳配分的影响

采用内耗和三维原子探针结合硬度测试研究了深冷处理对高碳高合金工具钢SDC99不同回火温度下组织和碳偏聚情况的影响。结果表明:深冷处理显著提高工具钢SDC99的硬度,深冷处理试样较淬火试样硬度提高2HRC,深冷处理并200℃回火试样比常规热处理试样硬度提高1.5HRC;深冷处理后碳原子与位错的相互作用增强,内耗的Snoek-Kê-K?ster(SKK)峰强度提高,位错密度增加;深冷处理后碳原子的偏聚程度加剧,淬火、深冷、淬火并200℃回火、深冷并200℃回火试样中富碳相的碳浓度峰值分别为2%、8%、8%和15%(原子分数)。     

铝合金的深冷处理研究

铝合金在工业生产上的应用极其重要，对其进行深冷处理有着重要的意义。深冷处理不仅可以改善铝合金的力学性能，还能大幅度提高工件的使用寿命，使得铝合金的深冷处理可以广泛的应用于生产实践中。现今，国内外对深冷处理的研究较为丰富，但多数是关于高速钢等黑色金属的，对于铝合金的深冷处理的研究还显得不够系统与深入。本文结合了国内外学者对于铝合金的深冷处理的研究成果并结合自己的看法，对深冷处理对铝合金的性能影响、铝合金深冷处理机理的研究以及铝合金的深冷处理工艺等进行了综述，并对未来的研究方向提出自己的看法，以期为以后的研究提供一定的参考。     

深冷处理改善高速钢性能及其机理研究

深冷处理是一种有效的热处理工艺方法，通过深冷处理后，能够比较显著地改善材料的力学性能和较大幅度地提高工件的使用寿命。深冷处理工艺在金属材料领域的应用已经越来越广泛。研究表明，深冷处理不仅可以使残余奥氏体减少，而且还可以细化马氏体孪晶，促使纳米级碳化物的析出，并附着在马氏体孪晶带上。深冷处理不仅可以提高材料的硬度，也能够使材料的韧性略有增加。经过深冷处理，能够有效促使残留奥氏体向马氏体转变，并且析出超微细碳化物，可以获得比较好的综合力学性能，显著提高高速钢刀具的使用寿命。本文介绍了深冷处理工艺的特点和它的发展情况，阐述了深冷处理工艺对高速钢材料的影响，并展望了深冷处理工艺的发展前景。     

深冷处理对低碳高合金马氏体轴承钢力学性能及组织的影响

利用洛氏硬度计、X射线衍射仪、扫描电子显微镜及透射电子显微镜等研究了低碳高合金马氏体轴承钢深冷处理后的硬度变化及组织演化。结果表明:深冷处理促使部分残留奥氏体转变为马氏体,导致深冷处理后实验钢的硬度较淬火态硬度有所升高。经深冷处理后实验钢在0~100 h回火过程中的硬度均比未深冷处理实验钢的硬度高。深冷处理促使钢中碳原子偏聚并在回火过程中以碳化物的形式析出,与未经深冷处理的实验钢相比,经深冷处理的实验钢回火后马氏体基体中的含碳量更低,表明实验钢经深冷处理后在回火过程中析出更多的碳化物。透射电镜分析表明,实验钢在回火过程中析出的大量弥散分布的纳米级M2C和M6C型碳化物是实验钢长时间回火后保持高硬度的主要原因。     

铝合金深冷处理研究进展

深冷处理作为传统热处理的补充能够提高材料的耐磨性、尺寸稳定性和综合力学性能,广泛应用于钢铁材料。近年来,深冷处理在铝合金方面的研究和应用取得了一些进展,本文对铝合金深冷处理方面的研究进展进行了系统的综述,重点分析了深冷处理在改善铝合金力学性能、尺寸稳定性和耐腐蚀性方面的宏观效果及其与处理工艺之间的关系,并从微观相组织、位错、晶格结构等不同尺度对微观组织方面的研究成果进行综述和分析,从而为铝合金深冷处理的研究和应用提供一定的指导。     

深冷处理对GCr15组织和力学性能的影响

对经不同深冷处理后的GCr15钢进行了组织观察、力学性能检测和摩擦磨损试验。试验结果表明:深冷处理可提高GCr15钢的硬度;淬火后进行深冷处理+180℃×8h回火处理后,GCr15钢的冲击韧性有所降低;深冷处理可明显提高GCr15钢耐磨性并降低钢中残留奥氏体含量,其中深冷处理6h后效果最为显著,其相对磨损率下降了30%、残留奥氏体含量降幅高达81%。     

深冷处理对AISI 310S不锈钢耐腐蚀磨损性能的影响

研究了深冷处理对AISI 310S不锈钢在3.5%(质量分数)Na Cl溶液中耐腐蚀磨损性能的影响,将310S不锈钢在-196℃进行保温深冷处理,结果表明:相对未深冷处理,深冷处理之后,材料的晶粒得到细化,更多碳化物弥散析出基体;深冷处理之后材料的耐腐蚀性能得到提高,在深冷处理4 h时达到最佳值,相比未深冷处理,自腐蚀电位从-0.525 V提高到-0.423 V,提升了19.4%;且深冷处理之后,材料的耐腐蚀磨损性能得到提升,经过深冷处理4 h,材料的磨损率从120×10-6mm3/Nm降低到63×10-6mm3/Nm,降低90%。     

铜合金的深冷处理研究

本文主要综述了金属深冷处理的发展历史,简要介绍了铜合金经深冷处理后性能的变化,国内外对深冷处理提高铜合金性能及其机理的研究。结合本人所阅读的文献综述了国内有关铜合金的深冷处理现状以及相关机理研究,就目前这个领域存在的问题和发展趋势进行了讨论。     

纳米技术在建筑材料中的发展与应用

综述了纳米科技的基本概念、产生、发展及其战略意义,讨论了国内外近几年纳米材料和纳米技术的研究成果及应用发展,并对纳米材料在高强度和高韧性纳米陶瓷材料、新型纳米结构的玻璃、塑料和橡胶制品、粘合剂、密封胶和润滑剂、特殊的光学性能材料、催化剂、水泥添加剂、新型防护材料、静电屏蔽材料、耐热、隔热、阻燃材料、涂料等建材领域的直接应用以及其潜在价值进行了讨论。     

Breakthrough Technologies for the Biorefining of Organic Solid and Liquid Wastes

Organic solid and liquid wastes contain large amounts of energy, nutrients, and water, and should not be perceived as merely waste. Recycling, composting, and combustion of non-recyclables have been practiced for decades to capture the energy and values from municipal solid wastes. Treatment and disposal have been the primary management strategy for wastewater. As new technologies are emerging, alternative options for the utilization of both solid wastes and wastewater have become available. Considering the complexity of the chemical, physical, and biological properties of these wastes, multiple technologies may be required to maximize the energy and value recovery from the wastes. For this purpose, biorefining tends to be an appropriate approach to completely utilize the energy and value available in wastes. Research has demonstrated that non-recyclable waste materials and bio-solids can be converted into usable heat, electricity, fuel, and chemicals through a variety of processes, and the liquid waste streams have the potential to support crop and algae growth and provide other energy recovery and food production options. In this paper, we propose new biorefining schemes aimed at organic solid and liquid wastes from municipal sources, food and biological processing plants, and animal production facilities. Four new breakthrough technologies—namely, vacuum-assisted thermophilic anaerobic digestion, extended aquaponics, oily wastes to biodiesel via glycerolysis, and microwave-assisted thermochemical conversion—can be incorporated into the biorefining schemes, thereby enabling the complete utilization of those wastes for the production of chemicals, fertilizer, energy (biogas, syngas, biodiesel, and bio-oil), foods, and feeds, and resulting in clean water and a significant reduction in pollutant emissions.     

Augmented body surveillance: Human microchip implantations and the omnipresent threat of function creep

Implanted microchips can store users' medical, financial, and other personal information, and provide users with easy and quick access to various locations and items. While adopted for their convenience outside of the healthcare sector, these invasive, semi-permanent implantable devices create augmented bodies that can be subject to ubiquitous surveillance. Situating human microchip implantations within surveillance literature, we draw from neoliberal perspectives of surveillance to examine augmented bodies, particularly as sources for market activity and as subjects of social control and sorting when these bodies are used as access control mechanisms, payment methods, and tracking means in employment, residential, commercial, and transportation sectors. History has demonstrated time and time again how unfettered technology applications and uses have led to real and/or perceived misuse by private and public sectors. Through the lens of function creep, we identify a pattern of expansion of applications and uses of technology beyond those originally intended across new technologies, such as DNA genetic genealogy databases, IoT wearables, and COVID-19 contact tracing apps, and provide illustrative examples of function creep, particularly the use of these technologies in criminal investigations and prosecutions despite not being intended or marketed for such use. By demonstrating the lack of clearly defined boundaries in the applications and uses of various new technologies and their associated data, and the ways they were misused, we demonstrate how human microchip implantations are headed on a similar path. The current and potential future uses of this technology raise concerns about the absence of regulation, law, and policy barring or limiting its application and use in specific sectors, and the impact of this technology on users’ security, data protection, and privacy. Undeniably, the present and potential future functions, applications, uses, and extensions of human microchip implantations in various sectors warrant a proactive examination of their security, privacy, and data protection consequences and the implementation of proactive policies to regulate new and currently unregulated uses of this technology and its associated data within these sectors.     

Materials and technologies for multifunctional,flexible or integrated supercapacitors and batteries

Electrochemical energy storage has become a key part of portable medical and electronic devices, as well as ground and aerial vehicles. Unfortunately, conventionally produced supercapacitors and batteries often cannot be easily integrated into many emerging technologies such as smart textiles, smart jewelry, paper magazines or books, and packages with data-collection or other unique capabilities, electrical cables, flexible wearable electronics and displays, flexible solar cells, epidermal sensors, and others in order to enhance their design aesthetics, convenience, system simplicity, and reliability. In addition, conventional energy storage devices that cannot conform to various shapes, are typically limited to a single function, and cannot additionally provide, for example, load bearing functionality or impact/ballistic protection to reduce the system weight or volume. Commercial devices cannot be activated by various stimuli, be able to self-destroy or biodegrade over time, trigger drug release, operate as sensors, antennas, or actuators. However, a growing number of future technologies will demand batteries and hybrid devices with the abilities to seamlessly integrate into systems and adapt to various shapes, forms, and design functions. Here we summarize recent progress and challenges made in the development of mostly nanostructured and nanoengineered materials as well as fabrication routes for energy storage devices that offer (i) multifunctionality, (ii) mechanical resiliency and flexibility and (iii) integration for more elegant, lighter, smaller and smarter designs. The geometries of device structures and materials are considered to critically define their roles in mechanics and functionality. With these understandings, we outline a future roadmap for the development, scaleup, and manufacturing of such materials and devices.     

Nanotechnology and health safety--toxicity and risk assessments of nanostructured materials on human health

The field of nanotechnology has recently emerged as the most commercially viable technology of this century because of its wide-ranging applications in our daily lives. Man-made nanostructured materials such as fullerenes, nanoparticles, nanopowders, nanotubes, nanowires, nanorods, nanofibers, quantum dots, dendrimers, nanoclusters, nanocrystals, and nanocomposites are globally produced in large quantities due to their wide potential applications, e.g., in skincare and consumer products, healthcare, electronics, photonics, biotechnology, engineering products, pharmaceuticals, drug delivery, and agriculture. Human exposure to these nanostructured materials is inevitable, as they can enter the body through the lungs or other organs via food, drink, and medicine and affect different organs and tissues such as the brain, liver, kidney, heart, colon, spleen, bone, blood, etc., and may cause cytotoxic effects, e.g., deformation and inhibition of cell growth leading to various diseases in humans and animals. Since a very wide variety of nanostructured materials exits, their interactions with biological systems and toxicity largely depend upon their properties, such as size, concentration, solubility, chemical and biological properties, and stability. The toxicity of nanostructured materials could be reduced by chemical approaches such by surface treatment, functionalization, and composite formation. This review summarizes the sources of various nanostructured materials and their human exposure, biocompatibility in relation to potential toxicological effects, risk assessment, and safety evaluation on human and animal health as well as on the environment.     

基于桂北传统建筑的旅游文化创意产品设计研究

目的 分析桂北地区建筑的文化精神、造型、结构、装饰、技艺等内容,将其应用到旅游文化创意产品中,使所设计的产品具有桂北传统建筑文化符号的特征,以此促进桂北传统建筑文化的传承及旅游业的发展。方法 首先对桂北地区的建筑类型进行分类整理,从聚落公共建筑、天井式地居和干栏式楼居的造型、结构,以及建筑局部的屋檐、柱、门簪、柱础、门、窗、栏杆等装饰元素入手,挖掘、凝练、整理、归纳其文化符号和视觉元素;其次遵循旅游文化创意产品地域性、文化性、创意性、便携性等原则,对提取的元素进行解构、重构、融合等设计创新;最后进行设计实践。结论 结合桂北传统建筑文化元素进行旅游创意产品设计,可以提升产品的内涵与价值,让人们了解桂北建筑文化,有利于桂北建筑文化的保护和传播。通过研究处理好建筑内容、元素提取、恰当载体、设计方法的关系,为基于桂北建筑文化的创意产品设计提供一些参考。     

审美意识对人工智能与创新设计的影响研究

目的探讨人工智能等新型科技影响下审美意识的嬗变,以及审美意识对人工智能与创新设计的方法、策略与表现形式的引导转化,审美意识统领下设计方法与设计评判的思辨,以及对可持续发展目标的再审视。方法采用了对比研究法、文献调查法、案例分析、认知计算法、社会计算、文化计算等人工智能研究方法。结果以中国为例,提出"统、象、生、场、中、简、空、衡"八大审美意识,分析审美意识对人工智能时代智能体的创新机制与设计方法的影响。结论创新设计的审美意识的"鉴"、"赏"、"创"3个方面,在感知、感受、趣味、理想、标准、创新6个维度形成了对人工智能与创新设计的交互影响,包括感知认知计算、体验感质协同、三体鉴别辨赏、具身离身心智、普适普惠意义、时空永续共生6个方面。     

Al-Si合金变质元素及其交互作用

铸造Al-Si合金具有轻量化、流动性好、气密性好、收缩率小和热膨胀系数低等优点,已成为铸造业中最受重视的结构材料之一。铸造Al-Si合金的力学性能主要取决于组织中的α-Al相、共晶硅、初生硅、金属间化合物、缺陷以及它们的形态、尺寸和分布,其中硅相和富Fe相的形貌、尺寸及分布对合金性能的影响尤为显著。未变质的Al-Si合金中针片状共晶硅和针状β-Fe相严重割裂基体,粗大块状初生硅和针片状共晶硅尖端和棱角部位产生应力集中,导致合金的性能尤其是塑性、强度和耐磨性显著降低。此外,硬脆的粗大初生硅还会加快机加工刀具的磨损,加工后零部件的表面光洁度也较差,无法满足实际生产的需要。快速凝固、电磁搅拌、超声处理、机械振动等特殊工艺技术虽然可以在一定程度上改善铸造铝硅合金的微观组织和性能,但是都需要专门的设备和特殊的条件,使其应用受到限制。变质处理不需要任何特殊设备,只需添加少量变质元素,就可以实现对其中α-Al相、共晶硅、富Fe相、细化初生硅等的有效调控,具有成本低、方法简单、效果显著等特点,已成为改善Al-Si合金组织、提高性能最有效的途径。然而,各变质元素的变质机理及它们之间的交互作用极其复杂,如何充分发挥各变质元素及它们之间积极的交互作用是当前的研究热点。近年来对单一变质元素的变质作用机理和效果的研究进展迅速,先后发现了Na、Sr、Sb、P、Ti、Mn和RE等都对铸造铝硅合金有一定的变质作用,并且对它们的变质时效性以及经济性都有了充分的认识。与此同时,也有许多研究者开始关注多元素的交互变质作用并在Sr-X、P-X、Mn-X、Ti-X等二元交互变质方面取得了重要的成果,使变质技术更加经济、有效和灵活。本文综述了铸造Al-Si合金常用单一变质元素的特点、变质作用机理和局限性,系统归纳了Sr、P、Ti、Mn和RE与其他元素间的交互作用规律,筛选出具有协同变质作用的二元/多元变质元素交互作用对,以期为深入探究二元/多元变质元素交互作用的机理,开发更高效、多样、绿色的复合变质剂及变质处理方法提供参考。     

Recent Advances in Biointegrated Optoelectronic Devices

With recent progress in the design of materials and mechanics, opportunities have arisen to improve optoelectronic devices, circuits, and systems in curved, flexible, stretchable, and biocompatible formats, thereby enabling integration of customized optoelectronic devices and biological systems. Here, the core material technologies of biointegrated optoelectronic platforms are discussed. An overview of the design and fabrication methods to form semiconductor materials and devices in flexible and stretchable formats is presented, strategies incorporating various heterogeneous substrates, interfaces, and encapsulants are discussed, and their applications in biomimetic, wearable, and implantable systems are highlighted.     

Guided wave nuances for ultrasonic nondestructive evaluation

Recent developments in guided wave generation, reception, and mode control show that increased penetration power and sensitivity are possible. A tone burst function generator and appropriate signal processing are generally used. Variable angle beam and comb-type transducers are the key to this effort. Problems in tubing, piping, hidden corrosion detection in aging aircraft, adhesive and diffusion bonding, and ice detection are discussed. Additionally, sample configurations, inspection objectives, and logic are being developed for such sample problems as defect detection and analysis in lap splice joints, tear straps, cracks in a second layer, hidden corrosion in multiple layers, cracks from rivet holes, transverse cracking in a beam, and cracks in landing gear assembly. Theoretical and experimental aspects of guided wave analysis include phase velocity, group velocity, and attenuation dispersion curves; boundary element model analysis for reflection and transmission factor analysis; use of wave structure for defect detection sensitivity; source influence on the phase velocity spectrum, and the use of angle beam and comb transducer technology. Probe design and modeling considerations are being explored. Utilization of in-plane and out-of-plane displacement patterns on the surface and longitudinal power distribution across the structural cross-section are considered for improved sensitivity, penetration power, and resolution in nondestructive evaluation. Methods of controlling the phase velocity spectrum for mode and frequency selection are available. Such features as group velocity change, mode cut-off measurements, mode conversion, amplitude ratios of transmission, and reflection factors of specific mode and frequency as input will be introduced for their ability to be used in flaw and material characterization analysis.