齿轮磨前滚刀的齿形研究

介绍了磨前滚刀滚切齿轮的最大根切量和磨后的渐开线长度计算，并建立了数学模型。为更加直观起见，还建立了模拟滚齿的数学模型，并在实验的基础上提出了参考标准。     

靠模式圆管滚切技术研究

介绍了圆管滚切技术的发展现状,分析了靠模式圆管滚切装置的工作原理和特点,建立了靠模曲线的数学模型,为曲线槽加工提供了理论依据。     

链轮齿形啮合特性的研究

本文以滚子链传动为例,建立了实际链条与实际滚切链轮相啮合的数学模型;推导了各项啮合特性参数的计算公式;并就两种实际滚切链轮齿形作了比较详细的对比分析;提出了链轮的通用齿形。     

椭圆齿轮滚齿加工三维仿真研究

为验证椭圆齿轮滚切模型的正确性,基于工具(斜)齿条原理,采用MATLAB软件进行三维仿真研究。推导了椭圆齿轮滚切数学模型,阐述了滚切仿真原理及实施方法,对直齿轮3种平面联动方式和斜齿轮2种附加运动形式分别进行三维滚切仿真。证实了椭圆齿轮滚切模型及各种滚切方法正确可行,数学处理方法对真实数控系统的开发及其他加工方法的仿真验证有借鉴价值。     

曲轴类零件滚磨光整加工技术的开发与研究

根据曲轴类零件表面光整加工的实际要求,提出并制定了卧式滚磨光整加工的工艺方案,在阐述加工机理的基础上,重点分析了磨块与工件表面间复杂的相对运动,建立了数学模型,分析了影响加工的主要因素,最后以曲轴滚磨光整加工实例表明该工艺是提高表面质量和改善使用性能的理想工艺。     

平面齿轮滚刀的参数分析

利用滚切法解决了在平面齿轮插削加工中齿轮轮齿易被切尖、切短的难题。根据滚削加工中相关参数的变化和联系建立数学模型,运用解逆向问题的方法约束在轮齿不变尖条件下的滚刀参数,为正确选用滚刀和得到理论精确的平面齿轮奠定了基础。     

数控滚齿加工自动编程技术的研究

为了提高齿轮加工的工作效率,提出了一种数控滚齿加工自动编程系统。首先,建立了数控滚齿-轴向滚切法的数学模型;然后,建立数控滚齿加工自动编程系统的硬件平台,对系统进行了功能模块划分和软件页面集设计;最后,对系统开发中的面向对象软件编程技术、通信技术、多线程技术、译码技术等做了分析。该技术为今后齿轮滚齿数控加工的便利提供了一些参考和经验。     

基于专家推理的滚抛磨块优选模型研究

滚抛磨块的优选是滚磨光整加工工艺方案制定的关键,针对目前滚抛磨块优选中存在的工作量较大、智能化程度较低等问题,提出基于专家推理的滚抛磨块优选模型。首先,根据实际加工的成功案例确定各特征值等级范围及隶属区间,并与滚抛磨块建立联系,利用产生式规则表示法建立区间值模糊规则;然后,通过层次分析法确定模糊规则中各特征属性的权重,并采用区间值模糊推理算法进行滚抛磨块优选推理机的设计;最后,进行了大量的实验仿真,并将推理结果与实际结果进行了比较。实验结果表明,该方法可用于滚磨光整加工工艺实施时的滚抛磨块优选,为新工艺的加工方案制定提供决策指导,提高了生产效率。     

球形磨头铣磨加工钛合金的铣磨力模型与实验研究

以球形磨头上单颗磨粒的铣磨力模型为基础,结合有效磨粒数和单位铣磨力模型,建立球形磨头铣磨力数学模型,为验证铣磨力数学模型的正确性,进行球形磨头铣磨钛合金实验,分析铣磨参数对铣磨力的影响规律,进而给出铣磨参数的选取建议。结果表明：建立的磨头铣磨力数学模型与铣磨实验结果符合铣磨力变化规律,数值上平均误差为5.6%;铣磨力随着主轴转速提高有显著降低并趋于平缓趋势,而随着铣磨进给速度与铣磨深度增大,铣磨力呈线性增加;铣磨夹角从45°增至75°,切向和法向铣磨力增大了数倍,轴向铣磨力仅增大50%,因此,加工时应选择较小的铣磨夹角。     

滚齿渐开线起始圆直径的计算

在齿轮加工中，滚齿、剃（磨）齿工艺很常见。我们希望剃后或磨后的齿轮齿根既没有沉切，也不要出台。因此，对滚齿后齿轮的沉切要做到心中有数，对滚刀的齿顶圆角或突角给一个合理的设计参数是必要的。通过渐开线起始圆直径计算公式的建立，用计算机编制的程序，很容易得到沉切值。我们计算的结果与SU和DR图样做了对比，基本相差不大。     

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.     

Discussion on advanced manufacturing

Advanced manufacturing consists of continuity of manufacturing, its broad sense, and the core of the manufacturing process. The technology of continuous manufacturing is discussed according to both historical and modern perspectives. The relationship between human development and manufacturing technology is also discussed. Manufacturing is a continuously evolving topic. It is not only the foundation and means of imagination, conception, the science, and the technology of material change, but also the expression of national economy, national defense, and the support industries. The broad sense of manufacturing theory, which extends the concept of manufacturing, is an important development in the 20th century. The sense is analyzed in connection with design, material forming theory, synthesis of manufacturing technology, manufacturing modes, life cycle of product, hardware and software, and support environment, etc. At the same time, the core action and the development of the theory and technology of process is also discussed. At the end of this paper, the development directions of mechanical manufacturing science and technology are mentioned.     

Wear mechanism of disc-brake block material for new type of drilling rig

To improve friction and wear performance and service life of the disc-brake pair material of a drilling rig, a new type of asbestos-free frictional material with better performance for disc-brake blocks is developed, and its wear mechanism is investigated by friction and wear experiments. Topography and elementary components of the brake block’s wear surface are analyzed by employing SEM and EDAX patterns, revealing its tribological behaviour and wear mechanism. When the frictional temperature is lower, the surface film of the brake block is thinner, dense, smooth with plasticity, and divided into the mixture area, Fe-abundant area, carbon-abundant area and spalling area. The mixture area consists of various constituents of frictional pairs without ploughing and rolling trace. The Fe-abundant area mainly consists of iron and other constituents. The carbon-abundant area is the zone where graphite and organic fibre are comparatively gathered, while the spalling area is the zone where the surface film is spalled and its surface is rough and uneven, with a loose and denuded state. During the period of high frictional temperature, the frictional surface is also divided into the mixture area, Fe-abundant area and spalling area. In this case, the mixture area consists of abrasive dust from friction pairs, and the surface film is distributed with crumby hard granules, exiguous oxide, carbide granules and sheared slender fibre. The Fe-abundant area is mostly an oxide layer of iron with a flaky distribution. Fracture and spalling traces as well as an overlapping structure of multilayer surface films can be easily found on the surface film. The components of the spalling area are basically the same as that of the matrix. At the beginning of wear, the hard peaks from the friction surface of the disc-brake plough on the surface of the brake block. With increasing frictional temperature, the friction surface begins to soften and expand, and oxidized wear occurs at the same time. During the high-temperature wear period, severely influenced by friction heat, obvious softening and plastic flow can be found on the friction surface of the brake block, its anti-shearing ability is weakened, and adhesive wear is intensified. Thermal decomposition of cohesive material in the brake block is simultaneously strengthened, so that constituents shed due to loss of adhesion. Organic fibre is in a flowing state and obviously generates drawing, shearing, carbonization and oxidization. In addition, thermal cracking, thermal oxidization, carbonization and cyclization of organic substances on the surface of brake block can make the friction surface produce pores or cracks, thus fatigue wear occurs.     

可展开固体反射面机构设计及运动学分析

针对传统固体反射面机构主反射面型面精度和收拢率较低的问题,设计了一种可展开固体反射面机构。首先,提出4种固体反射面机构可展单元构型并对其机构自由度进行分析,对比分析构型方案优缺点确定构型方案4作为可展单元基础构型,并对其结构和展开原理进行详细设计。通过D-H坐标变换建立该机构可展单元的运动学模型,根据几何约束条件建立机构位置矢量方程,利用向量封闭投影法解出各回转角间的关系,结合MATLAB软件编程对机构的位置、速度和加速度进行分析。应用ADAMS软件建立机构仿真模型,验证了机构运动学分析的正确性。最后根据机构中回转角的限制条件和结构尺寸关系,分析回转角和结构尺寸对可展开固体反射面机构收拢率的影响,确定2.2m可展开固体反射面机构的回转角和旋转角分别为78°和30°,中心圆盘半径、铰支座一孔纵向尺寸、切换连杆横向尺寸、纵向尺寸分别为245,8,40,18mm,收拢率为0.326,从而为可展开固体反射面机构的设计提供参考。     

Fixed-point and stratified analysis of the fine structure and composition of five gallstones with Fourier transform infrared (FT-IR) specular reflection spectroscopy

By investigating the identities, amounts, and distributions of the major components of human gallstones, the formation mechanism of calculi may be elucidated. Using FT-IR specular reflection spectroscopy, the compositions of five common types of gallstones, including cholesterol calculus, bile pigment calculus, cholesterol-bilirubin calculus, mixed calculus, and black stones, were positionally, qualitatively, and quantitatively analyzed. Several organic and inorganic substances were found in human gallstones, including cholesterol, calcium bilirubinate, calcium carbonate, calcium phosphate, and calcium stearate. Among them, cholesterol and calcium bilirubinate were the main components. The amounts of these substances varied in different types of gallstone. The distributions of cholesterol and calcium salts (with the exception of calcium bilirubinate) were also closely associated with location. In the various calculi, the amounts of cholesterol and calcium bilirubinate in the cores, the layered structures outside the cores, and the outer shells were higher than those of other substances. The identities of the major components of calculi were similar in different types of gallstones, but their amounts and distributions were significantly different. The analytical method used in this study, which was able to accurately determine the location, quality, and quantity of the major components of gallstones, would be an effective tool to study the formation mechanism of calculi.     

电过滤纸喷雾离子源的性能优化及应用研究

常压离子源是质谱技术在生命科学、环境保护、医药卫生、食品安全等领域的研究热点之一.随着质谱分析技术的应用范围越来越广,直接快速分析复杂体系的化合物组成和含量越发重要.本工作基于已研制的小型化离子阱质谱和电过滤纸喷雾离子源,对其分析性能和应用进行深入研究.以提高质谱信号强度和检测灵敏度为目标,对所用滤纸的孔径、离子源尖端...     

理想材料零件的数字化设计制造方法及内涵

提出了理想材料零件的新概念 ,它是指按零件的最佳使用功能要求来设计 ,由呈梯度变化的组织成分和一定规律分布的细结构的材料与均质材料所组合构成的新型材料零件。提出并阐明了理想材料零件的数字化的并行设计制造 (简称数字化设计制造技术 )的方法和理论基础 ;它以材料与零件的一体化、集成化设计制造为主要特点 ,可根据零件功能要求进行零件的外部几何拓扑形状和内部材料组织细结构的并行设计 ,并采用增材制造和去材制造相结合的制造技术 ,按数字化设计的信息 ,一次完成零件内部组织结构和三维形体的制造。指出数字化设计制造将会使人们长期以来设想的按力学、电磁学性能来高效地设计制造新材料零件变为现实 ,在不远的将来定能像设计和建造房屋那样 ,按照所需功能设计制造理想材料零件。     

智能垃圾分拣系统的模拟与实现

针对当今世界城市生活垃圾不断增长造成的自然环境污染和资源浪费等问题,对我国和欧美等发达国家的城市生活垃圾分类收集和分类处理方面进行了对比研究,对发达国家在城市生活垃圾处理过程中的安全分类处理方式和垃圾再利用策略进行了归纳,结合国内外垃圾分类处理所遇到的问题和不足,设计制造出了一套实现垃圾桶颜色识别、路线识别、机械手动作和到达指定位置的自动化垃圾分拣系统模型,利用Code Warrior 5.0软件开发平台对系统程序在线调试,通过系统的反复运行对智能分拣小车的自动寻迹进行了累积误差统计试验.研究结果表明,智能垃圾分拣系统的累积误差波动稳定,寻迹的能力比较准确、可靠,实现了垃圾自动分拣的过程,为工业的应用实现提供了有利的参考和理论依据.     

Wear mechanism of disc-brake block material for new type of drilling rig

To improve friction and wear performance and service life of the disc-brake pair material of a drilling rig, a new type of asbestos-free frictional material with better performance for disc-brake blocks is developed, and its wear mechanism is investigated by friction and wear experiments. Topography and elementary components of the brake block’s wear surface are analyzed by employing SEM and EDAX patterns, revealing its tribological behaviour and wear mechanism. When the frictional temperature is lower, the surface film of the brake block is thinner, dense, smooth with plasticity, and divided into the mixture area, Feabundant area, carbon-abundant area and spalling area. The mixture area consists of various constituents of frictional pairs without ploughing and rolling trace. The Fe-abundant area mainly consists of iron and other constituents. The carbon-abundant area is the zone where graphite and organic fibre are comparatively gathered, while the spalling area is the zone where the surface film is spalled and its surface is rough and uneven, with a loose and denuded state. During the period of high frictional temperature, the frictional surface is also divided into the mixture area, Feabundant area and spalling area. In this case, the mixture area consists of abrasive dust from friction pairs, and the surface film is distributed with crumby hard granules, exiguous oxide, carbide granules and sheared slender fibre. The Fe-abundant area is mostly an oxide layer of iron with a flaky distribution. Fracture and spalling traces as well as an overlapping structure of multilayer surface films can be easily found on the surface film. The components of the spalling area are basically the same as that of the matrix. At the beginning of wear, the hard peaks from the friction surface of the disc-brake plough on the surface of the brake block. With increasing frictional temperature, the friction surface begins to soften and expand, and oxidized wear occurs at the same time. During the high-temperature wear period, severely influenced by friction heat, obvious softening and plastic flow can be found on the friction surface of the brake block, its anti-shearing ability is weakened, and adhesive wear is intensified. Thermal decomposition of cohesive material in the brake block is simultaneously strengthened, so that constituents shed due to loss of adhesion. Organic fibre is in a flowing state and obviously generates drawing, shearing, carbonization and oxidization. In addition, thermal cracking, thermal oxidization, carbonization and cyclization of organic substances on the surface of brake block can make the friction surface produce pores or cracks, thus fatigue wear occurs.     

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.