在气调条件下某些水果的呼吸率和呼吸热

本文研究测定了在贮藏温度为１０℃，１５℃、２０℃、２５℃和３０℃每一温度下，控制ＣＯ２和Ｏ２浓度分别为５％和５％、５％和１０％、５％和１５％、１０％和５％、１０％和１０％、１０％和１５％、１５％和５％、１５％和１９％和１５％和１５％时，绿色香蕉、芒果、橙的呼吸率和呼吸热。结果显示呼吸率和呼吸热随着ＣＯ２浓度的上升而关少，随着Ｏ２浓度和温度的下降而减少，在没ＣＯ２和Ｏ２浓度下，呼吸率和呼吸热随着温度     

国外兵器包装的发展趋势

兵器包装必须满足运输、储存和方便部队使用的基本要求。在兵器运输和储存中,必须防止水、水蒸汽、氧、空气中携带的二氧化硫和盐粉等有害物、风、尘、紫外线、霉菌和昆虫等的腐蚀和侵害。电子产品、     

欢迎订阅2019年度《工程设计学报》

正《工程设计学报》刊登工程设计领域及其新兴交叉学科领域具有创新性和前沿性的高水平基础研究、应用研究的成果论文;鼓励理论结合实践,注重学术界和工业界合作,追求学术性和实用性的统一。《工程设计学报》内容涉及广泛,包括设计理论和方法学、创新设计、并行设计、优化设计、评价与决策、结构静动态分析和设计、面向制造的设计、设计专家系统和智能工程、面向装配和维修的设计、CAD/CAPP/CAM一体化、摩擦学设计、多媒体设计方法和技术、可靠性设计、工业设计等各方面。内容新颖,注重创新性和实用性,     

浅析企业标准化和质量管理

一、企业标准化与质量管理的关系 1．企业标准化的定义：企业标准化是企业在生产、经营、管理活动中,通过贯彻、引用有关标准和制定、发布、实施企业标准,达到统一,使企业获得最佳秩序和技术经济效益。它是一项涉及面较广的技术经济工作,它的活动贯穿到产品设计、工艺和工装的设计与制造、自制设备、原材料采购和供应、零部件的加工、产品检验和包装、产品销售和服务、生产组织和经营管理等方面。     

检定、校准和检测结果的质量控制

正一、检定、校准和检测结果质量控制的目的影响机构检定、校准和检测结果质量的因素包括人员、设备、设施与环境条件、样品、方法、溯源性、与结果有关的材料等,有效控制这些影响因素即可保证检定、校准和检测结果的准确、可靠。因此,需要机构定期对检定、校准和检测结果的准确性进行验证。检定、校准和检测结果的质量控制实质上就是应用实验和统计的方法,定期对检定、校准和检测的结果进行验证,找出造成结果偏离     

欢迎订阅2020年度《工程设计学报》

正《工程设计学报》刊登工程设计领域及其新兴交叉学科领域具有创新性和前沿性的高水平基础研究、应用研究的成果论文;鼓励理论结合实践,注重学术界和工业界合作,追求学术性和实用性的统一。《工程设计学报》内容涉及广泛,包括设计理论和方法学、创新设计、并行设计、优化设计、评价与决策、结构静动态分析和设计、面向制造的设计、设计专家系统和智能工程、面向装配和维修的设计、CAD/CAPP/CAM一体化、摩擦学设计、多媒体设计方法和技术、可靠性设计、工业设计等各方面。内容新颖,注重创新性和实用性,     

钛和钛合金的腐蚀与防腐

本文比较系统地介绍了钛和钛合金耐腐蚀的原因,以及在各种条件下:包括水流冲刷、在天然水和严重污染的海水中,电腐蚀、氯化物、氯气、次氯酸盐、氧化性酸、还原性酸、有机化学物质、有机酸等对钛和钛合金腐蚀的影响和防腐注意事项和方法。还介绍了钛合金的抗污垢性能,以及应力腐蚀裂纹和氢脆产生的条件和预防方法.适合于军用和民用工业的广泛范围.     

油画般迷幻的塔川

<正>在宏村、在协里、在塔川,秋如此缤纷。那些或殷红或深紫或鹅黄或金黄或翠绿的、色彩斑斓的乌桕树,有的孤单站立,有的两两相依,和老屋、和草垛、和溪流、和远山、和水车、和老牛、和流岚、和秋阳,抑或和那些由一垅一垅田地构成的色块、线条随意搭配,组成一幅绝美的秋色图。难怪乎这里被推崇为中国三大秋色之一,成为摄影人创作的天堂!在村庄,在田园,秋如此诗意。黄昏时分,秋那眩目的华丽重归淡泊和安宁。斜阳草树,坳里人家,     

欢迎订阅2019年度《工程设计学报》

正《工程设计学报》刊登工程设计领域及其新兴交叉学科领域具有创新性和前沿性的高水平基础研究、应用研究的成果论文;鼓励理论结合实践,注重学术界和工业界合作,追求学术性和实用性的统一。《工程设计学报》内容涉及广泛,包括设计理论和方法学、创新设计、并行设计、优化设计、评价与决策、结构静动态分析和设计、面向制造的设计、设计专家系统和智能工程、面向装配和维修的设计、CAD/CAPP/CAM-体化、摩擦学设计、多媒体设计方法和技术、可靠性设计、工业设计等各方面。内容新颖,注重创新性和实用性,     

北京国实检测技术研究院招聘信息

正北京国实检测技术研究院是为检验检测机构和实验室提供资质认定和认可的综合性研究和服务机构。研究院秉承"科学、公正、诚信、独立"的服务理念,以提升检验检测机构和实验室技术能力、提高检验检测机构和实验室服务水平为己任,通过科研、培训、咨询和交流为资质认定管理部门和检验检测机构、实验室提供技术支撑,具体承担资质认定和认可科学研究、技术培训、标准制定、政策解读和国际交流等研究     

钢中非金属夹杂物的鉴定

根据钢中非金属夹杂物的来源和分类,综述了鉴定钢中非金属夹杂物的方法和定量评级标准,并且给出了典型夹杂物的扫描电镜照片,分析了不同类型夹杂物的形成机理及其在光学显微镜下的基本特征.     

In-plane impact behavior of honeycomb structures randomly filled with rigid inclusions

The in-plane impact behavior of honeycomb structures randomly filled with rigid inclusions was studied by using the finite element method to clarify the effect of inclusions on the deformation process, mean stress, densification strain, and absorbed energy. The deformation processes of the models were disturbed by inclusions; shear bands were pinned, and the cell regions surrounded by inclusions were shielded. Mean stress, densification strain, and absorbed energy per unit volume normalized by the values of the model without inclusions were found to be only dependent on the fraction of inclusions. As the volume fraction of inclusions increased, the normalized mean stress linearly increased and the normalized densification strain linearly decreased. The normalized absorbed energy per unit volume could be approximated by an inverted parabolic equation. The energy absorption of models with inclusions having volume fractions from 0 to 0.25 was larger than that of the models without inclusions. In particular, honeycomb models with fractions of inclusion from 0.1 to 0.2 exhibited the maximum absorbed energy. The model with a volume fraction larger than 0.4 could not be compressed because the inclusions in the model had already percolated before deformation. The in-plane impact behavior of honeycomb structures as energy absorbing materials can be designed by using the approximate equation and selecting the volume fraction of inclusions.     

FGH96合金反复镦拔与挤压缺陷对比分析

对FGH96合金反复镦拔变形与挤压变形两种制坯工艺的夹杂缺陷水平进行了比较,并分析了不同变形状态下非金属夹杂物的形变特性。结果表明:反复镦拔变形后,锻件内检测到的非金属夹杂物数量有不同程度的增多,超标缺陷成倍增长;而FGH96合金挤压+等温锻造变形后,锻件内检测到的非金属夹杂物数量明显减少,纯净度水平有大幅提高。从微观夹杂物形貌的变形特性来看,等温锻造变形时在垂直于变形方向合金中夹杂物缺陷的尺寸增大;反复镦拔变形时,合金中原有非金属夹杂物缺陷聚集使可检测到的缺陷面积增大;而在挤压变形过程中,夹杂物缺陷在挤出方向被拉长成不连续的线状,每个方向上夹杂物的面积均减小;FGH96合金挤压+等温锻造变形后夹杂缺陷的大小主要由挤压变形后夹杂缺陷破碎情况决定;因此大挤压比变形可有效破碎合金中非金属夹杂物,改善锻件质量。     

钢液预处理→120t转炉→钢包精炼→真空脱气→连铸流程生产GCr15轴承钢的纯净度

对7炉采用钢液预处理→120t转炉→钢包精炼→真空脱气→连铸流程生产的GCr15轴承钢进行了氧、氮及残余元素含量分析、非金属夹杂物评级、夹杂物电子探针观察和能谱分析以及电解夹杂物等分析。结果表明:采用该流程生产的GCr15轴承钢的纯净度较高,尤其是氮元素含量和残余元素含量均比电炉流程生产的GCr15轴承钢明显降低;钢中的夹杂物主要是铝酸钙和氧化铝,也有少量的硫化物和氮化物,而且总是以复合夹杂物的形式存在。     

非金属夹杂物特性对钢铁材料疲劳性能影响的研究进展EI北大核心CSCD

本文综述了非金属夹杂物对钢铁材料疲劳性能的影响及研究现状,从夹杂物的角度出发,首先介绍非金属夹杂物特征提取的最新研究进展,分别从实验测量方法和数学公式科学统计方法两方面进行论述;其次根据夹杂物对于疲劳损伤的主要原理,介绍5种应用较为广泛的定量化分析夹杂物特征参数与钢材疲劳性能的数学模型;然后以夹杂物的形貌特征、力学性能以及与基体之间的相互作用为出发点,探究非金属夹杂物的特性对重载零件钢材疲劳性能的影响。最后指出从多角度解析非金属夹杂物对钢材疲劳性能的主要作用机理,构建非金属夹杂物对钢材疲劳寿命预测模型是未来该领域的研究重点。     

06Cr19Ni10不锈钢中大型夹杂物的分析

通过对06Cr19Ni10不锈钢连铸坯中存在的大型夹杂物的形貌和化学成分进行分析,找出了大型夹杂物的形成原因,并给出了防止该类大型夹杂物产生应采取的措施。结果表明：06Cr19Ni10不锈钢中的大型夹杂物属于以CaO-SiO2-Al2O3-MgO为主要成分的脆性夹杂物;初步分析认为该大型夹杂物是在冶炼过程中没有上浮的炉渣在连铸时裹入钢液中形成的,也有可能是沉积在结晶器上的氧化物被下泄的钢液冲入结晶器中进而进入连铸坯所致。     

The determination of steel cleanliness in the as-cast steel ingot 26NiCrMoV145

The content and the type of non-metallic inclusions in the as-cast ingot for open-die forgings made from 26NiCrMoV145 steel were determined. The standard methods for the determination of non-metallic inclusions are suitable only for the wrought steels, so a modified standard method for the determination of the non-metallic inclusions in the as-cast steel was performed. Analyzed samples were taken from three different positions on the ingot. The determination of the type of the non-metallic inclusions was made by EDS analysis. The content of the non-metallic inclusions was determined using an optical microscope.     

Detrimental effect of nitride and aluminium oxide inclusions on fatigue life in rotating bending of bearing steels

Abstract

Rotating bending fatigue tests were performed on hardened AISI type 52100 bearing steel. Fracture surfaces after testing at a stress amplitude of 950 MPa showed that the Ti(C,N) inclusions which caused fatigue failure were significantly smaller than the corresponding alumina inclusions. The smallest crack initiating Ti(C,N) inclusion had a size of 3 μm and the smallest alumina inclusion was 17 μm. It was also shown that fatigue life was significantly shorter for a steel which showed cracked alumina inclusions on the fracture surfaces than for a steel which had non-cracked inclusions. Finite element calculations were performed to determine the driving forces of short cracks at Ti(C,N) and alumina inclusions. Two configurations were studied in each case, based on both non-cracked and cracked inclusions. The calculations incorporated heat treatment simulation and cyclic loading with successive growth of cracks. It was found that the Ti(C,N) configurations gave the highest driving forces for crack growth. The alumina configuration with a non-cracked inclusion gave the lowest driving force. It was concluded based both on experimental evidence and theoretical considerations that Ti(C,N) inclusions are more detrimental to fatigue life than alumina inclusions of the same size. It is their shape and thermal properties which make Ti(C,N) inclusions more detrimental than alumina inclusions. Internal cracking of alumina inclusions leads to reduced fatigue life.     

Effects of various parameters on ultrasonic separation of inclusions from magnesium alloy melt

The acoustic radiation force generated by ultrasonic standing wave in the flow media can make solid particles suspending in the liquid agglomerate at the nodal planes of the waves and then realize their separation, which is also known as ultrasonic agglomeration in chemical industry. In this paper, ultrasonic waves were employed to promote and accelerate the separation of inclusions from magnesium alloy melt, and the effect of acoustic radiation forces on oxide inclusions removal from magnesium alloy melts were studied by numerical calculation. The agglomeration behavior of the inclusions was also obtained by solving the equations of motion for inclusions. Finally, parametric studies, usually very helpful for continued optimization and design efforts, were carried out to evaluate the effects of various parameters such as ultrasonic power, ultrasonic treating time, particle size and density difference between particle and melt on the inclusions distribution. The results indicate that when a moderate ultrasonic power was applied, most of inclusions could agglomerate at wave nodes in a short time which finally enhanced and accelerated the separation of inclusions from magnesium alloy melt.     

KDP晶体包裹体的拉曼光谱研究

激光显微拉曼光谱对KDP晶体包裹体研究发现,相邻锥扇界附近的球形溶液包裹体串只有水溶液,而柱面扩展包藏和含高密度散射颗粒的KDP晶体都存在CO₂和H₂S等杂质分子.我们推断,柱、锥面包裹体成分的不同与晶体不同面的生长特征有关,CO₂等杂质气体分子的存在是柱面包裹体和散射颗粒形成的原因之一.