Recent progress in synthesis,properties and potential applications of SiC nanomaterials

As nanotechnology rapidly advanced over the past decades, a variety of nanomaterials have been developed and studied. Among them, SiC nanomaterials have recently attracted increasing attention for their demonstrated unique chemical and physical properties as well as wide potential applications. This article provides a comprehensive review of the recent progress on the synthesis, novel properties, and applications of SiC nanomaterials. It begins with the introduction of various techniques used for the rational design and synthesis of SiC nanomaterials, with an emphasis on vapor-based and solution-based methods. Discussion is then made on the mechanical, luminescent, electrical, thermal, and wetting properties of SiC nanomaterials as well as the characterizations that reveal them. Thereafter, various intriguing applications particularly in composites, field emitters, field effect transistors, sensors, nanoelectromechanical devices, catalyst, supercapacitors, bioimaging probes and microwave absorbers are highlighted. Finally, this review is concluded with an outlook of future research on SiC nanomaterials, major challenges to be met and possible solutions.     

Recent progress in electrochemical reduction of carbon monoxide toward multi-carbon products

The increasing CO₂ emissions and accompanying climate challenges have boosted the exploration of candidate pathways for storing and utilizing renewable carbon resources. Electrochemical CO₂ reduction (ECO₂R) has been proven as a promising technology for artificial carbon fixation. Nevertheless, the unsatisfactory multi-carbon (C₂₊) product selectivity hinders its widespread use. Recently, the indirect route via electrochemical CO reduction (ECOR) to C₂₊ products has become a potential alternative through the combination with ECO₂R. In this review, we briefly summarize the most recent and instructive research in the ECOR development process from advanced ECOR catalysts and reaction mechanisms. Furthermore, the challenges and outlooks based on current understanding in this field are expounded. These insights and perspectives offer meaningful guidance for grasping ECOR and designing relevant catalysts with enhanced C₂₊ product selectivity.     

Development of a geometry-based process planning system for surface micromachining

There are many CAD systems developed for the design and fabrication of MEMS (Micro-Electro Mechanical Systems). However, most of them simulate the construction process given the two-dimensional mask data, and few systems generate the fabrication process plan from a designed model. Furthermore, the current systems simulate the construction process based on the two-dimensional geometry data. In this paper, a new process planning technique that uses a three-dimensional surface micromachined structure as input is proposed. The system decomposes an imported surface micromachined model into a set of three-dimensional models, each of which has the geometry compatible with the fabrication process, and then groups them for efficient layer generation. Finally, it generates the fabrication order and the masks for all the layers of the structure.     

表面等离子共振氢气传感研究进展

基于表面等离子共振原理的光学氢气传感已经成为氢气传感技术研究的热点.表面等离子共振传感器具有安全可靠、灵敏度高、实时性好、便于分布式多点检测等优点,在氢气泄漏检测方向具有广阔的应用前景.本综述介绍了表面等离子共振氢气传感器的三种主要结构类型:棱镜耦合结构,光栅耦合结构和光纤耦合结构的检测原理、典型结构及其研究进展;重点论述了表面等离子共振氢气传感技术中氢敏感膜系的研究现状和技术难题;分析了目前表面等离子共振氢气传感实际应用所面临的瓶颈,并对未来的研究方向进行了展望.结合实际,提出了开发基于光纤微结构和纳米材料的新型氢气传感器件,并且将传感原理延伸至局域表面等离子体共振,表面等离子体共振成像等新兴技术.     

膜蒸馏技术应用最新研究进展

作为一种新型热驱动膜分离技术,膜蒸馏具有相较于传统蒸馏及压力驱动膜分离技术更低的操作压力和温度,可充分利用工业余热、地热和太阳能等能源为其提供热动力,再加之其理论上100％的截留性能,使膜蒸馏成为极具吸引力的膜分离技术,已广泛应用于水处理、食品、医药和特种分离等领域.对近年来国内外膜蒸馏应用现状进行综述,并提出膜蒸馏在...     

中空玻璃微球近期技术发展和应用

综述了国内外人造中空玻璃微球的制造技术及发展趋势,着重叙述了中空玻璃微球制备吸波材料、中空玻璃微球制备高强度浮力材料的技术发展状况,并介绍了国内外主要生产厂家及产品应用情况.     

Microstructures using RF sputtered PSG film as a sacrificial layer in surface micromachining

In this paper, we explore RF magnetron sputtered Phosphor-silicate-glass (PSG) film as a sacrificial layer in surface micromachining technology. For this purpose, a 76 mm diameter target of phosphorus-doped silicon dioxide was prepared by conventional solid-state reaction route using P₂O₅ and SiO₂ powders. The PSG films were prepared in a RF (13·56 MHz) magnetron sputtering system at 300 watt RF power, 20 mTorr pressure and 45 mm target-to-substrate spacing without external substrate heating. Microstructures of sputtered silicon dioxide film were fabricated using sputtered PSG film as sacrificial layer in surface micromachining process.     

Fabrication of diamond microstructures for microelectromechanical systems (MEMS) by a surface micromachining process

Selective polycrystalline diamond thin film has been grown on a silicon dioxide/silicon substrate using high pressure microwave plasma-assisted chemical vapor deposition from a gas mixture of methane and hydrogen at a substrate temperature of 950°C. A simple process flow has been developed to fabricate diamond microstructures such as diamond beams and cantilever beams using surface micromachining and photolithography for the first time. Scanning electron and optical microscopy has been used to characterize the surface micromachined diamond microstructures.     

Plasmonic properties of polycrystalline hollow Au nanoparticles: a surface roughness effect

Hollow Au nanoparticles with a 25 nm polycrystalline shell and a 50 nm hollow core were produced in large amounts by using electrochemically evolved hydrogen nanobubbles as templates and reducing agents for electroless deposition from a Na3Au(SO3)2 electrolyte. The surface roughness of these nanoparticles can be tuned by adding NaSO3 into the electrolyte. Different surface roughnesses can be readily obtained for sub-100 nm particles with the same size. As surface roughness increases, surface plasmon resonance (SPR) peaks shift to longer wavelengths. Particles with an 8 nm roughness have a SPR peak centered at 750 nm, which is particularly attractive for in vivo diagnostic and therapeutic applications. A three-dimensional finite difference time domain (FDTD) simulation confirms that the red-shifts of SPR peaks are mainly caused by their surface roughness, and the hollow nature of these particles plays only a minor role. This unique plasmonic property of hollow Au nanoparticles opens up the possibility to maintain the desirable optical properties after loading other substances into the hollow core to form multifunctional core-shell nanoparticles.     

我国煤层气田地面集输工艺及监测技术研究进展

针对我国煤层气田地域特点和煤层气地面低压集输存在的问题,通过实施国家科技重大专项项目,研究提出了集中式与分散式相结合的我国煤层气田地面集输模式,对煤层气田地面集输系统的低压集输工艺、撬装式液化设备、产出水处理与环境保护技术、集输系统自动数据采集和网络化管理等关键技术及科学问题进行了联合攻关,获得了重大技术突破,初步形成了适应我国煤层气产业化特点的地面集输工艺与监测技术体系,研发了一系列低成本、生产安全、经济实用的重要装备和试运行系统,并依托国家煤层气开发示范工程基地进行了实际应用。     

金属表面制备绿色环保防腐膜技术的研究进展EI北大核心CSCD

金属表面防腐技术一直是工业工程领域的关注重点。随着科技进步和对环境保护的关注,对绿色环保的要求也逐渐成为当前金属表面防腐技术的重要指标之一。本文综述了近年来金属表面绿色环保防腐涂层制备技术的研究进展。在综合国内外文献基础上,对金属表面防腐涂层中3种典型新技术,即自组装膜技术、缓蚀剂以及分子筛膜技术的分类、特点和应用、防腐机理等进行了讨论。指出了涂层添加剂和石墨烯涂层等其他可行的绿色环保防腐涂层技术,以及自组装膜技术、缓蚀剂以及分子筛膜技术在体系构建、工艺优化以及复合涂层设计等方面的发展趋势。     

Recent progress on polyimide aerogels against shrinkage: a review

Polyimide aerogels are promising for diverse applications owing to their nanoporous structure and superior performance in thermal insulation, dielectric protection, etc. However, the severe shrinkage they usually suffer has long been a threat, and can pose great challenges to their shape-stable preparation and reliable applications. It is very important to clarify the effects of various factors on the shrinkage of PI aerogels and the effective strategies available for shrinkage reduction. These are also the focuses of the present review, to provide guidance for preparing PI aerogels with greatly reduced shrinkage, and thereby improved shape stability and use reliability. Since the shrinkage of PI aerogels is quite a complex issue, further studies on PI aerogels against shrinkage deserve continuous attention.

Graphical abstract

     

Recent progress on magnetic iron oxide nanoparticles: synthesis,surface functional strategies and biomedical applications

Abstract

This review focuses on the recent development and various strategies in the preparation, microstructure, and magnetic properties of bare and surface functionalized iron oxide nanoparticles (IONPs); their corresponding biological application was also discussed. In order to implement the practical in vivo or in vitro applications, the IONPs must have combined properties of high magnetic saturation, stability, biocompatibility, and interactive functions at the surface. Moreover, the surface of IONPs could be modified by organic materials or inorganic materials, such as polymers, biomolecules, silica, metals, etc. The new functionalized strategies, problems and major challenges, along with the current directions for the synthesis, surface functionalization and bioapplication of IONPs, are considered. Finally, some future trends and the prospects in these research areas are also discussed.     

Remote sensing as a tool for achieving and monitoring progress toward sustainability

Airborne and satellite remote sensing have enormous potential for facilitating and monitoring the dynamics of intergenerational natural resource management and built environment sustainability. Based on reviews of (1) the development and current state of the science for deploying remote sensing, and (2) capabilities and limitations of the array of archival and real-time remotely sensed resources as tools for attaining and monitoring sustainability, we suggest several "best practices" for incorporating remote sensing within sustainability plans for selected rural and urban ecosystems. We present sustainability indices for case studies relating to sustainable forestry, agriculture, watersheds, and urbanizing areas, as well as a conceptual prototype for incorporating remotely sensed data within a general purpose decision support system that highlights the benefits of multi-temporal historical change detection in monitoring past and ongoing change, and in visualization of alternative future scenarios. Finally, we examine the sustainability of remote sensing technology, itself, with respect to economic pressures, public policy perturbations, systems resilience, biogenic factors and both inadvertent and deliberate anthropogenic impact.     

Recent progress on magnetic iron oxide nanoparticles: synthesis,surface functional strategies and biomedical applications

This review focuses on the recent development and various strategies in the preparation, microstructure, and magnetic properties of bare and surface functionalized iron oxide nanoparticles (IONPs); their corresponding biological application was also discussed. In order to implement the practical in vivo or in vitro applications, the IONPs must have combined properties of high magnetic saturation, stability, biocompatibility, and interactive functions at the surface. Moreover, the surface of IONPs could be modified by organic materials or inorganic materials, such as polymers, biomolecules, silica, metals, etc. The new functionalized strategies, problems and major challenges, along with the current directions for the synthesis, surface functionalization and bioapplication of IONPs, are considered. Finally, some future trends and the prospects in these research areas are also discussed.     

Relieving micro-strain by introducing macro-strain in a polycrystalline metal surface by cavitation shotless peening

Peening using cavitation impact is called “cavitation shotless peening CSP”, since there is no requirement for shot in the process. Micro- and macro-strain of polycrystalline metal peened by CSP were evaluated using X-ray diffraction methods, as the full width at half maximum (FWHM) of the X-ray diffraction profile from the peened surface was decreased, although compressive residual stress was introduced. It was found that CSP reduced the micro-strain in the surface, but simultaneously introduced compressive residual stress, i.e., a macro-strain. The results demonstrate that the micro-strain is relieved by CSP without the need for heat treatment, and is, therefore, a sort of annealing. Thus, CSP can renew the metallic material while the shape itself is maintained.     

Fracture surface roughness as a gauge of fracture toughness: Aluminium-particulate SiC composites

Fracture toughnesses of several composites of aluminium alloys reinforced with particulate SiC have been measured. The variables were particulate size and volume fraction, and matrix alloy composition and heat treatment. Fracture surface profiles were measured and related to fractal dimension using the techniques of quantitative metallography. The fracture surface roughness was described well by fractals, but fracture toughness did not correlate with any measure of fracture surface roughness. An explanation for this behaviour is offered.     

Chinese truck drivers' attitudes toward feedback by technology: a quantitative approach

This study examined Chinese truck drivers' attitudes toward receiving feedback about their driving performance by in-cab technology and explored the best ways of providing feedback to truck drivers in China. The similarities and differences between US and Chinese drivers were also compared. Survey data were collected from 200 long-haul truck drivers in China to provide quantitative information. The results of the current study were compared to the results of a previous study published in 2006 which utilized focus group discussions with Chinese truck drivers, and to the data of a similar survey conducted in the US and published in 2005. Results of the current study showed that Chinese truck drivers were eager for more feedback about their driving performance and they were willing to receive feedback from technology. Although negative feedback was most prevalent in their working environment and was considered acceptable if it improves driving safety, they considered positive feedback as more helpful to safe driving. They perceived many benefits of receiving feedback by technology and comparatively few drawbacks and concerns. Compared to US truck drivers who strongly preferred feedback from a human (e.g., safety director, dispatcher) rather than from technology, Chinese truck drivers were more positive in terms of receiving feedback from technology. They considered feedback from technology to be more objective and scientific than feedback from humans. This study showed the importance of considering cross-culture differences when planning to apply interventions in different countries and cultures.