现代设计理论方法在机械系统设计中的应用

阐述了传统机械系统设计方法和机械系统的现设计理论方法的特征;在传统机械系统设计的基础上提出了机械系统动态设计的概念、方法、目的等;并介绍了机械系统的建模方法及动态设计方法;提出对机械系统进行动态优化设计的方法。     

工控设备设计中应关注的几个问题

就工控设备的热稳定性和电磁兼容性提出了注意事项和改进办法;对于电路"死锁"提出了一种解决的方法;对于有效利用看门狗电路提出了分散喂狗和条件喂狗的思路;对于关键信号量和配置信息提出了校验方法和保护措施.     

数控系统运动控制性能的测试方法研究

以脉冲信号为对象,研究了数字和模拟两种采集方法的测试原理和误差;设计专用算法解决了模拟采集方法存在的非实时性问题,弥补了数字采集方法测量误差大的缺点;最后给出了测试实例。     

[退役产品拆卸和回收利用]面向再制造的拆卸线平衡问题建模理论及求解方法综述

对国内外拆卸线平衡问题的研究成果进行了总结和梳理。对该问题进行了描述并介绍了2种关于拆卸的可视化表示方式和经典的数学模型;梳理了文献中的求解方法并分为精确方法、启发式方法、元启发式方法三大类;重点总结和分析了拆卸线平衡问题相关的8种扩展模型和理论;对未来的研究方向进行探讨和展望,为下一步研究提出了建议。     

农产品、食品安全检测方法与仪器的进展

农产品和食品安全是世人十分关注的问题。本文论述了食品安全监测体系技术支撑(即检测方法和仪器)中的几个问题,包括农产品、食品安全检测的特殊性;对检测方法和仪器的要求;检测方法和仪器的现状,以及国际上得到确认的检测方法;对检测方法和仪器发展趋势的预测。     

一种空中定位新方法分析

新方法与其它定位方法进行了比较;对其采用的原理及公式作了说明;就此对该方法进行了详细论述.最后指出该定位方法的近期和远期应用前景.     

基于线性匹配方法的核电站弯管在循环载荷下的安定性分析

进行了核电站90°弯管在内压和面内弯曲载荷作用下的棘轮效应试验,并采用数值方法研究了90°弯管的极限载荷、安定载荷和棘轮边界。利用理想弹塑性有限元分析,基于两倍弹性斜率准则和切线相交准则分别确定了90°弯管单独承受内压和弯曲载荷的极限载荷;利用线性匹配方法确定了90°弯管在单独内压和弯曲载荷以及两者共同作用下的极限载荷和安定载荷;利用Ohno-Wang模型,结合C-TDF弹塑性有限元分析方法和线性匹配方法分别确定了90°弯管的棘轮边界;最后,对弹塑性有限元方法和线性匹配法确定的棘轮边界进行了比较。结果表明：两倍弹性斜率准则、切线相交准则和线性匹配方法确定的极限载荷误差为10.78%,其中弹性迭代的线性匹配法能高效、快速地进行计算。比较C-TDF法和线性匹配法确定的棘轮边界,结果发现：当内压在20~35 MPa之间时,两种方法确定的棘轮边界吻合很好;当内压小于20 MPa时,两种方法的预测结果呈现不同的趋势。     

数控车床位置精度检测与评定方法对比分析

为了得到最佳的数控车床位置精度检测和评定方法,介绍了数控车床常用的位置精度测量工具和方法,对几种检测方法进行了对比分析,介绍了目前国内外常用的4种评定标准;利用激光干涉仪测量某重型数控车床位置精度值,利用上述4种评定标准对位置精度具体指标——定位精度、重复定位精度、反向差值和系统偏差进行计算,对计算结果进行了分析对比;明确了各种评定方法的具体运用情况,从而为数控车床的生产、验收和使用中的位置精度检测提供指导。     

一种基于选择性激光烧结的快速成型新方法构想

介绍了选择性激光烧结的工作原理和特点;基于选择性激光烧结,提出了密排电阻丝烧结这种新型快速成型方法构想;介绍了密排电阻丝烧结方法的工作原理、成型材料以及成型设备;通过对成型设备和工作原理的分析,总结了密排电阻丝烧结的优缺点;基于以上探讨,指出了密排电阻丝烧结快速成型方法的发展前景与趋势。     

广义BOM时间建模

针对广义BOM建模中的时间模糊性和约束多样性问题,提出了BOM时间的多色图描述方法。采用模糊数表达BOM时间,通过图的“着色”实现多种时间约束的表达;建立了BOM时间到时间约束网络的映射规则,给出了BOM时间一致性的判定和求解方法;最后通过实例对BOM时间模型及其求解方法进行了验证。     

Human fetal ductal plate revisited. I. ductal plate expresses NCAM,KIT, MET,PDGFRA, and neuroendocrine antigens (NSE,chromogranin, synaptophysin,and CD56)

Background: The molecular mechanisms of ductal plate (DP) development and differentiation (DD) in human fetal livers (HFLs) are unclear. Materials and Methods: The author immunohistochemically investigated expressions of NCAM, KIT, KIT, PDGFRA, and neuroendocrine antigens in 32 HFLs. Results: The processes of human intrahepatic bile duct (IBD) DD could be categorized into four stages: DP, remodeling DP, remodeled DP, and mature IBD. NCAM was always expressed in DP and remodeling DP, but not in remodeled DP and mature IBD. The biliary elements were positive for cytokeratin (CK)7, 8, 18, and 19. The hepatoblasts were positive for CK8 and CD18, but negative for CK7 and CK19; however, periportal hepatoblasts showed biliary‐type CKs (CK7 and CK19). NCAM was always expressed in DP and remodeling DP, but not in remodeled DP and mature IBD. KIT was occasionally (12/32 cases) expressed in DP and remodeling DP, but not in remodeled DP and mature IBD. NCAM expression was also seen in some hepatoblasts and hematopoietic cells and neurons. KIT was also expressed in some hepatoblasts, hematopoietic cells, and mast cells. MET and PDGFRA were strongly expressed in DP, remodeling DP, remodeled DP, and mature IBD. MET and PDGFRA were also strongly expressed in hepatoblasts and hematopoietic cells. MET and PDGFRA were not expressed in portal mesenchyme, portal veins, sinusoids, and hepatic veins. DP showed immunoreactive chromogranin, synaptophysin, neuron‐specific enolase (NSE), and CD56. Expressions of chromogranin and CD56 were infrequently seen in remodeling DP. No expressions of these four neuroendocrine antigens were seen in remodeled DP and mature IBD. The nerve fibers were consistently positive for chromogranin, synaptophysin, NSE, and CD56 in the portal mesenchyme in the stages of remodeling DP, remodeled DP, and mature IBDs. Conclusions: The data suggest that NCAM, KIT/stem cell factor‐signaling, NSE, hepatocyte growth factor/MET signaling, PDGFα/PDGFRA signaling, chromogranin, synaptophysin, and CD56 play important roles in DD of biliary cells of HFL. They also suggest that the DP cells having neuroendocrine molecules give rise to hepatic stem/progenitor cells. Microsc. Res. Tech. 77:814–824, 2014. © 2014 Wiley Periodicals, Inc.     

Histochemical and ultrahistochemical localization of heavy metals in calf organs

Cadmium, zinc, selenium, and copper were administered, singly or in combination, orally or subcutaneously. Experiment I included 32 calves of both sexes; six received Cd (two groups), Zn, Cd, and Zn, and Cd and Se (two groups) and one group was a control. In Experiment II (21 bulls), three were given Cd, Cd, and Cu, and Cd and Zn, respectively, and one group was a control. For light microscopy, in Experiment I the highest amounts of silver granules were present in the samples of liver, small intestine, and vesicular gland of all the exposed groups; in Experiment II the most affected organs were liver, kidney, and small intestine. For electron microscopy, in Experiment I, after administration of Cd and Zn, the highest amounts of granules were seen in the cytoplasm of hepatocytes and cells of the proximal and distal renal tubules and the lowest amounts were found in glandular cells of the pancreas. Administration of Cd and Se resulted in the presence of large numbers of granules in the nuclei and nucleoli of spermatogonies. In Experiment II, ingestion of Cd and Zn in feed led to the appearance of highest amounts of granules in the nucleoli, nuclei, and cytoplasm of cells in testes, kidneys, and pancreas. Following Cd intake, the highest accumulation of granules was observed in the nucleoli of hepatocytes and cells of the proximal and distal renal tubules. Combined Cd and Cu produced the highest number of granules in cells of the proximal and distal renal tubules and in the nucleoli and nuclei of germinal epithelium.     

Epibiotic microorganisms on copepods and other marine crustaceans

Although the occurrence of microbial (algal, protozoan, bacterial, and fungal) epibionts on marine crustaceans and other invertebrates has been documented repeatedly, the ecological context and significance of these relationships generally are not well understood. Recently, several studies have examined the population and community ecology of algal and protozoan epibionts on freshwater crustaceans. Even so, the study of microbial epibionts in aquatic environments is still in its infancy. In this review, we summarize associations of microalgae, protozoans, and bacteria with marine crustaceans, especially copepods. We note differences and commonalities across epibiont taxa, consider host-epibiont cycling of nutrients, generate hypotheses relevant to the ecology of the host and the epibiont, and suggest future research opportunities. Microsc. Res. Tech. 37:116–135, 1997. © 1997 Wiley-Liss, Inc.     

Taxonomic significance of caryopsis in subfamily Panicoideae (Poaceae) using scanning electron microscopy and light microscopy

In recent study, 13 taxa of subfamily Panicoideae were investigated for morphological characterization of caryopsis. Light microscope (LM) and scanning electron microscope (SEM) were utilized to study macro‐ and micro‐morphological caryopsis features respectively. Caryopsis size in studied taxa was recorded as 1.5–10 mm long and 1–4 mm wide. Caryopsis color was brown, green, yellow, and whitish‐brown. Caryopsis shape studied was obovate, elliptic, linear oblate, and round shallowly obtriangular. Hilum position is grooved and depressed. Caryopsis compression type was lateral and dorsiventral. Major variations among studied taxa were observed in terms of caryopsis surface pattern and epicuticular projection types. Six types of caryopsis surface pattern were observed viz. scabrate, rugose, striate, reticulate, papillate, and scabridulous. Structures such as silica cells, bulges, spines, prickles, granules, and bicellular microhair were studied as epicuticular projections. Major variations were observed among Cenchrus pennisetiformis and Cenchrus ciliaris as both has entirely two different types of surface patterns and epicuticular projections. Anticlinal wall thickness and pattern as well as periclinal wall texture and level were investigated. The present research work emphasized on caryopsis characterization of subfamily Panicoideae and it is recommended to establish phylogeny within subfamily Panicoideae and with other subfamilies of Poaceae.     

城市生活污水中阿片类、苯丙胺类以及苯二氮卓类滥用物质的高分辨质谱筛选及确证

本研究采用固相萃取对城市生活污水样品进行前处理,超高效液相色谱-串联高分辨质谱法筛选及确证污水中阿片类、苯丙胺类和苯二氮卓类等36种滥用物质,并将其应用于实际污水样品。结果表明,该方法的专属性强,36种滥用物质的检出限范围为5~20 ng/L。在12个污水样品中共检出吗啡、可待因、哌替啶、曲马多4种阿片类滥用物质,甲基苯丙胺1种苯丙胺类滥用物质以及地西泮、去甲西泮、艾司唑仑、阿普唑仑4种苯二氮卓类滥用物质。城市生活污水中存在多种滥用物质,区域流行性不同,利用本方法可进行快速、准确地筛选与确认。     

Assessment of PM-EDM cycle factors influence on machining responses and surface properties of biomaterials: A comprehensive review

Powder mixed-electro discharge machining (PM-EDM) is recently evolving machining technique which can simultaneously remove and modify the machined surface through thermo-electrical process. It is a modified form of EDM in which the conductive powder elements are added in the dielectric liquid to enhance machined surface characteristics and machining responses. The commonly used biomaterials such as 316L stainless steel, Ti-based alloy, Ni–Ti, Mg alloy, and Co–Mo–Cr alloy have excellent mechanical characteristics while the biofunction of these materials are not in satisfactory level. Due to higher hardness, brittleness, and heat resistant natures of the biomaterials, it is very challenging to machine them with conventional machining. Both the system efficiency and modified surface properties depend on the associated electrical and non-electrical factors of PM-EDM cycle. This review focuses on the influence of process factors such as current, pulse duration, tool-polarity, duty cycle, potential voltage, types of liquid, and added powder concentration on performance outputs including material removal and tool wear rate, coating thickness, coarseness, microhardness, coating adhesion bonding, biocompatibility, and resistant to corrosion. This study also discusses influence of various powders on machining and modified surface characteristics of biomaterials. The future research scopes and challenges of PM-EDM process are included in this study thoroughly.     

Review on microbial metabolomics of probiotics and pathogens: Methodologies and applications

In recent years, microbial metabolomics, a new field that has attracted wide attention, provides a map of metabolic pathways and clarifies the interaction mechanism between microorganisms and hosts. Many microorganisms are found in the human intestine, oral cavity, vagina, etc. Probiotics could maintain the good health of the host, while pathogens and an imbalance of bacterial flora lead to a series of diseases of the body and mind. Metabolomics is a science for qualitative and quantitative analysis of all metabolites in an organism or biological system, which could provide key information to understand the related metabolic pathways and associated changes. This approach analyzes the final products of cellular regulatory processes, the level of which can be regarded as the ultimate response of the biological system to genetic or environmental changes. Microbial metabolomics has been widely used in different research fields, such as microbial phenotypic classification, mutant screening, metabolic pathways, microbial metabolic engineering, fermentation engineering monitoring and optimization, microbial environmental pollution, and so on. However, there are only a few reviews on microbial metabolomics of probiotics and pathogens. This review summarizes the main methodologies, including sample preparation, identification of metabolites, data processing, and analysis. Recent applications in microbial metabolomics of probiotics and pathogens are also described. This paper first summarized the research progress and application of microbial metabolomics from two aspects: probiotics and pathogenic bacteria. Probiotics and pathogenic bacteria do not exist independently most of the time; hence, these were reviewed in the research field of coexistence of probiotics and pathogenic bacteria, which was subdivided into important microbial research fields closely related to human health, including the human gut, oral cavity, food, and nutrition-related microorganisms. Then, the main problems and trends associated with microbial metabolomics are discussed.     

Fiber-reinforced composites in milling and grinding: machining bottlenecks and advanced strategies

Fiber-reinforced composites have become the preferred material in the fields of aviation and aerospace because of their high-strength performance in unit weight. The composite components are manufactured by near net-shape and only require finishing operations to achieve final dimensional and assembly tolerances. Milling and grinding arise as the preferred choices because of their precision processing. Nevertheless, given their laminated, anisotropic, and heterogeneous nature, these materials are considered difficult-to-machine. As undesirable results and challenging breakthroughs, the surface damage and integrity of these materials is a research hotspot with important engineering significance. This review summarizes an up-to-date progress of the damage formation mechanisms and suppression strategies in milling and grinding for the fiber-reinforced composites reported in the literature. First, the formation mechanisms of milling damage, including delamination, burr, and tear, are analyzed. Second, the grinding mechanisms, covering material removal mechanism, thermal mechanical behavior, surface integrity, and damage, are discussed. Third, suppression strategies are reviewed systematically from the aspects of advanced cutting tools and technologies, including ultrasonic vibration-assisted machining, cryogenic cooling, minimum quantity lubrication (MQL), and tool optimization design. Ultrasonic vibration shows the greatest advantage of restraining machining force, which can be reduced by approximately 60% compared with conventional machining. Cryogenic cooling is the most effective method to reduce temperature with a maximum reduction of approximately 60%. MQL shows its advantages in terms of reducing friction coefficient, force, temperature, and tool wear. Finally, research gaps and future exploration directions are prospected, giving researchers opportunity to deepen specific aspects and explore new area for achieving high precision surface machining of fiber-reinforced composites.     

[学科发展]润滑研究进展

过去20余年,薄膜润滑、纳米润滑、极端工况摩擦与润滑、生物润滑、绿色润滑、微量润滑等取得了重要进展。最近10余年,超滑、仿生润滑、智能润滑与监测,以及摩擦学测试技术和模拟仿真技术等研究飞速发展。微观研究已经成为润滑研究的主要手段,面向风力发电机、高铁、深空探测、深海探测、大飞机、超高速飞行器、新能源汽车等领域的润滑与密封和绿色近零排放润滑研究已经成为工业界关注的焦点。超滑作为润滑领域的新型颠覆性技术,逐步显示出其在工业生产和人类日常生活中的应用优势与勃勃发展生机。生物润滑包括人类器官中的摩擦与润滑和仿生学研究,在人类健康生活方面展示出重要作用。极端环境（高温、超低温、真空、高压等）摩擦与润滑,在卫星、火箭、舰艇、核电站及其他国防设施上用途广泛。而智能润滑等新兴领域发展,也将智能化应用到润滑领域,为设备的智能运行和制造提供了新的思路。在此,对润滑领域几个重要发展方向,如超滑、薄膜润滑、纳米润滑、极端工况摩擦与润滑、智能润滑、生物仿生学、绿色摩擦与润滑,以及摩擦学测试方法等方面进行回顾,介绍了国内外同行最新研究进展,并对未来进行了展望。     

Ion mobility mass spectrometry in the omics era: Challenges and opportunities for metabolomics and lipidomics

Researchers worldwide are taking advantage of novel, commercially available, technologies, such as ion mobility mass spectrometry (IM-MS), for metabolomics and lipidomics applications in a variety of fields including life, biomedical, and food sciences. IM-MS provides three main technical advantages over traditional LC-MS workflows. Firstly, in addition to mass, IM-MS allows collision cross-section values to be measured for metabolites and lipids, a physicochemical identifier related to the chemical shape of an analyte that increases the confidence of identification. Second, IM-MS increases peak capacity and the signal-to-noise, improving fingerprinting as well as quantification, and better defining the spatial localization of metabolites and lipids in biological and food samples. Third, IM-MS can be coupled with various fragmentation modes, adding new tools to improve structural characterization and molecular annotation. Here, we review the state-of-the-art in IM-MS technologies and approaches utilized to support metabolomics and lipidomics applications and we assess the challenges and opportunities in this growing field.