一种新型电熔爆铣削机床的便捷拆装集电装置

设计了一种能承受大电流的电熔爆铣削机床使用的便捷拆装集电装置.该装置将旋转头的导电连接部分与旋转头功能分离,使电流直接导通在电极上,省去中间的电流耗损以及由此产生对其他部件的电蚀,有效解决了以往装置无法施加大电流这一技术难题.     

Recent advances in scanning x-ray microscopy

A scanning x-ray microscope has been built at the Daresbury synchrotron radiation source and used to obtain images at soft x-ray wavelengths (～2–4 nm). The focusing element of the microscope is a zone plate, fabricated by a contamination writing process developed at King's College. Zone plates with the finest zone widths, and hence theoretical resolutions, below 20 nm have been fabricated in this way. The contamination material is carbon, and as such is unsuitable for high-efficiency focusing. In order to increase the zone plate efficiency, a shadowing pattern transfer process has been developed and used to replicate contamination lines with 25 nm widths into more suitable materials.     

Recent advances in polymer composites' tribology

An overview is given on the friction and wear properties of high temperature resistant polymers, in particular polyetheretherketone (PEEK), under various testing conditions against smooth steel counterparts. The effects of internal lubricants, especially polytetrafluoroethylene (PTFE), and short fibre reinforcements (glass vs. carbon) are outlined. In addition, results of sliding wear experiments with continuous glass, carbon or aramid fibre-polymer matrix composites against steel were used to develop a hypothetical model composite with optimum wear resistance.     

Recent advances in magnetic force microscopy

During the past ten years magnetic force microscopy (MFM) has become probably the most powerful general-purpose method for magnetic imaging. MFM can be applied under various environmental conditions and requires only little sample preparation. Basic research on magnetic materials as well as the mentioned industrial applications create an increasing demand for high-resolution magnetic imaging methods. This contribution will review some new concepts which have been realized in the field of advanced probe preparation, based on electron beam methods in order to improve the spatial resolution beyond 100nm. It is shown that the advanced probes allow high-resolution imaging of magnetic fine structures within thin film permalloy elements exhibiting a complicated cooperative magnetization reversal process. These investigations are of importance for various concepts underlying modern magnetic data storage developments. Furthermore, we present some developments of MFM to suit the needs of the magnetic recording industry.     

Recent researches in micro electrical machining

The demand for micro parts and moulds has been increasing in various fields. Among the various micro machining technologies, micro electrical machining is one of the most widely used because it can be applied for conductive or nonconductive materials. This paper discusses the recent studies that explore many ways to improve micro electrical machining performance. Many researchers proposed ways to improve productivity and accuracy through experimental or analytical studies. The improved-performance trends of micro electrical machining are expected to continue thanks to the miniaturization of manufactured goods in a high-tech industry.     

扩散管采集技术的若干进展

介绍了近年来扩散管技术的进展,重点介绍了蜂窝状扩散管和湿式扩散管及其在大气采样中的应用,并对各种类型扩散管的特点进行了比较。     

Recent advances in atomic-scale spin-polarized scanning tunneling microscopy

The Mn3N2 (010) surface has been studied using spin-polarized scanning tunneling microscopy at the atomic scale. The principle objective of this work is to elucidate the properties and potential of this technique to measure atomic-scale magnetic structures. The experimental approach involves the use of a combined molecular beam epitaxy/scanning tunneling microscopy system that allows the study of atomically clean magnetic surfaces. Several key findings have been obtained. First, both magnetic and non-magnetic atomic-scale information has been obtained in a single spin-polarized image. Magnetic modulation of the height profile having an antiferromagnetic super-period of c = 12.14 A (6 atomic rows) together with a non-magnetic superstructure having a period of c/2 = 6.07 A (3 atomic rows) was observed. Methods of separation of magnetic and non-magnetic profiles are presented. Second, bias voltage-dependent spin-polarized images show a reversal of the magnetic modulation at a particular voltage. This reversal is clearly due to a change in the sign of the magnetic term in the tunnel current. Since this term depends on both the tip's as well as the sample's magnetic local density of states, the reversal can be caused by either the sample or the tip. Third, the shape of the line profile was found to vary with the bias voltage, which is related to the energy-dependent spin contribution from the 2 chemically inequivalent Mn sites on the surface. Overall, the results shown here expand the application of the method of spin-polarized scanning tunneling microscopy to measure atomic-scale magnetic structures.     

Recent advances in atomic force microscopy of DNA

Three advances involving DNA in atomic force microscopy (AFM) are reported here. First a HEPES-Mg buffer has been used that improves the spreading of DNA and provides good DNA coverage with as little as 200–500 picograms per sample. Second, the new “tapping” mode has been used to improve the ease and resolution of AFM-imaging of DNA in air. Finally, AFM images are presented of single-stranded ΦX-174 virion DNA with the gene 32 single-stranded binding protein. A summary of the current state of the field and of the methods for preparing and imaging DNA in the AFM is also presented.     

红外光谱技术的近代进展及其应用

对红外光谱技术的近代进展,如漫反射、衰减全反射、联用技术、差谱技术和数据压缩等及其应用作了简单地介绍。     

Recent advances in automatic image analysis using a television system

Image analysis, in the context of this paper, comprises the extraction of quantitative geometric and densitometric data from images produced by optical and electron microscopes or any other imaging system. Typical measurements include area percentages, intersect counts, feature counts, size distributions and integrated density determinations. Much of the stereological work is still performed by manual methods, but technological progress in recent years has considerably promoted the use of automatic image analysing devices. This paper describes recent developments in scanner performance and the correction of shading errors which allow reliable densitometric measurement. In addition, the previous geometric capabilities have been extended to include feature selection by pattern recognition criteria.     

Recent advances in separation of roughness, waviness and form

Engineering surfaces are comprised of a range of spatial wavelengths. Filtering techniques are commonly adopted to separate the different wavelength components into well-defined bandwidths. Filtering is done prior to numerical characterization and it is also essential for extracting information needed to provide process feedback and establish functional correlation. This paper reviews commonly used filters in surface metrology like the 2RC, Gaussian and several new ones currently under research such as the spline, morphological, wavelets, regression filters and robust regression filters. The need for these new filters and examples illustrating the features of these filters are also presented.     

脉冲涡流无损检测技术综述

不同于传统的谐波激励的涡流检测方法,脉冲涡流检测采用方波或阶跃方式激励,其测量的是涡流在构件中的衰减。由傅里叶理论可知,脉冲涡流激励中包含多种频率成分,根据电磁场理论,低频电磁波有更深的穿透深度,因而也就可能检测出更深的缺陷。由于脉冲涡流检测时,激励已经停止,因而传统涡流阻抗分析方法已经不适用于脉冲涡流检测信号分析,需要寻找新的信号处理方法或数据解释方法;同时由于导磁材料与非导磁性材料特性不同,信号特性差异极大,上述问题不论从理论上还是从工程上对脉冲涡流检测技术都提出了极大的挑战。从检测理论模型、传感器、信号处理方法及工程应用等方面,对脉冲涡流检测技术作论述,指出该技术进一步发展需要研究的问题,更好地推动脉冲涡流检测技术的发展。     

Recent advances and applications of high resolution electron microscopy

This review covers several broad areas: firstly, recent developments in HREM instrumentation, and then novel techniques for imaging are discussed, including some of the problems of image interpretation. Applications of HREM techniques to a wide range of materials problems are described and include solid state chemistry, ceramics, semiconductors, metals and natural diamonds. The next generation of high resolution microscopes will operate in the 300–400 kV range, have low C_s objective lenses, and have sufficiently good vacuum to allow the combined use of CBED and EELS facilities with imaging in the sub-2 Å range. Microprocessor control of instrumental parameters such as astigmatism, alignment and defocus are seen as an important way forward in achieving the optimum performance of these instruments.     

Recent advances in finite element modeling of the human cervical spine

The human cervical spine is a complex structure that is the most frequently injured site among all spinal injuries. Therefore, understanding of the cervical spine injury and dysfunction, and also biomechanical response to external stimuli is important. Finite element (FE) modeling can help researchers to access the internal stresses and strains in the bones, ligaments and soft tissues more realistically, and it has been widely adopted for spine biomechanics research. Although in recent years numerous techniques have been developed, there are no recent literature reviews on FE models of the cervical spine. Our objective was to present recent advances in FE modeling of the human cervical spine in terms of component modeling, material properties, and validation procedures. Model applications and further development are also discussed. The integration of new technologies will allow us to generate more accurate and comprehensive model of the cervical spine, which can increase efficiency and model applicability. Finally, the FE modeling can help to facilitate diagnosis, treatment, and prevention technologies for cervical spine injuries.     

Recent advances in wave-driven triboelectric nanogenerators:from manufacturing to applications

The ocean is the largest reservoir of renewable energy on earth,in which wave energy occupies an important position due to its high energy density and extensive distribution.As a cutting-edge technology,wave-driven triboelectric nanogenerators(W-TENGs)demonstrate substantial potential for ocean energy conversion and utilization.This paper provides a comprehensive review of W-TENGs,from materials manufacturing and structural fabrications to marine applications.It highlights the versatility in materials selection for W-TENGs and the potential for unique treatments to enhance output performance.With the development of materials science,researchers can manufacture materials with various properties as needed.The structural design and fabrication of W-TENGs is the pillar of converting wave energy to electrical energy.The flexible combination of TENG's multiple working modes and advanced manufacturing methods make W-TENGs'structures rich and diverse.Advanced technologies,such as three-dimensional printing,make manufacturing and upgrading W-TENGs more convenient and efficient.This paper summarizes their structures and elucidates their features and manufacturing processes.It should be noted that all efforts made in materials and structures are aimed at W-TENGs,having a bright application prospect.The latest studies on W-TENGs for effective application in the marine field are reviewed,and their feasibility and practical value are evaluated.Finally,based on a systematic review,the existing challenges at this stage are pointed out.More importantly,strategies to address these challenges and directions for future research efforts are also discussed.This review aims to clarify the recent advances in standardization and scale-up of W-TENGs to promote richer innovation and practice in the future.     

Recent advances in design and preparation of micro diamond cutting tools

Micro diamond tools are indispensable for the efficient machining of microstructured surfaces.The precision in tool manufacturing and cutting performance directly determines the processing quality of components.The manufacturing of high-quality micro diamond tools relies on scientific design methods and appropriate processing techniques.However,there is currently a lack of systematic review on the design and manufacturing methods of micro diamond tools in academia.This study systematically summarizes and analyzes modern manufacturing methods for micro diamond tools,as well as the impact of tool waviness,sharpness,and durability on machining quality.Subsequently,a design method is proposed based on the theory of cutting edge strength distribution to enhance tool waviness,sharpness,and durability.Finally,this paper presents current technical challenges faced by micro diamond tools along with potential future solutions to guide scientists in this field.The aim of this review is to contribute to the further development of the current design and manufacturing processes for micro diamond cutting tools.     

Recent developments in waste electrical and electronics equipment legislation in China

China has witnessed a rapid increase in waste electrical and electronics equipment (WEEE) in the recent years, but has not yet established corresponding recycling and disposal systems with appropriate administrative oversight. Consequently, most household waste appliances have neither been effectively recycled nor safely treated. However, efforts were made to improve the situations. Reviewing the history of China's legislation in this field since the 1990s, this paper affirms China's recent achievements in the last few years with commentary on several of the latest regulations and laws. Through the research on WEEE recycling chain and related laws, the authors first analyze the significant impact this legislation has imposed on manufacturing, recycling, treatment, and exportation/importation in China's household appliance industry. Secondly, the authors indicate various difficulties in the implementation of the newly made laws and regulations. Finally, the authors propose several practical suggestions with regard to promoting the implementation of these laws and regulations, based on the existing state conditions and the experience of other countries in the recycling industry, such as those of European countries, America, and Japan.     

Recent advances in bio-functional Ta-based bone materials:materials design and bioactivity

Ta-based materials have gained significant interest for bioimplantable scaffolds because of their appropriate mechanical characteristics and biocompatibility.To overcome the serious limitation of bioinertness,there have been many efforts to enhance the bioactivity and osseointegration of Ta-based scaffolds through morphostructural and surface modifications.As scaffolds are implantable devices,sufficient bioactivity is needed to trigger the cellular functions required for tissue engineering.Consequently,a combination of materials and bioscience is needed to develop efficient Ta-based scaffolds,although reviews of this interdisciplinary field remain limited.This review aims to provide an overview of the main strategies to enhance the bioactivity of Ta-based scaffolds,describing the basic mechanisms and research methods of osseointegration,and the approaches to enhance bioactivity and osseointegration.These approaches are divided into three main sections:(i)alteration of the micromorphology,(ii)customization of the scaffold structure,and(iii)functionalization modifications(through alloying or the addition of surface coatings).Also provided are recent advances regarding biocompatibility assessment in vitro,osseointegration properties in vivo,and clinical trial results.     

Minireview: Recent advances in the determination of flavonoids by capillary electrophoresis

Flavonoids are compounds which provide many pharmacological activities. In this paper, the literature with regard to the determination of flavonoids using capillary electrophoresis (CE) during 2008–2017 has been reviewed. The aim of the review is to overview the modes and specific determination conditions of CE for flavonoids. The advantages and disadvantages of CE in the determination of flavonoids are analyzed. The applications of the modes of CE for determination of flavonoids are introduced. Capillary zone electrophoresis, micelle electrokinetic capillary chromatography, microemulsion electrokinetic chromatography, and capillary electrochromatography are considered. Specific determination conditions including the pH, buffer, additive, capillary, voltage, temperature, injection, analysis time, detection, and online concentration methods are summarized. Flavonoids were generally separated in alkaline conditions at pH 8–10 in borate buffer. The advantages of CE are the short analysis time and low solvent consumption compared with the most popular high-performance liquid chromatography protocols. CE can be combined with a variety of detectors including ultraviolet spectrophotometry, mass spectrometry, chemiluminescence, electrochemical, potential gradient, dual opposite carbon fiber microdisk electrodes, and laser-induced fluorescence. In CE, short-light path length results in relative low sensitivity when combined with the most widely used ultraviolet spectrophotometry detector. The combination with more sensitive detectors and online concentration methods such as gradient elution, large volume sample stacking, sweeping, and electrokinetic supercharging alleviates this problem and improves the sensitivity. Capillary electrophoresis is an efficient, green, and valuable tool for the determination of flavonoids.