不锈钢螺母的钻孔、攻螺孔

在石油、化工行业机械设备及管道的紧固联接中，为了确保联接的牢固，严防腐蚀失效，不锈钢紧固件被广泛应用，其材质一般为铬不锈钢或铬镍不锈钢。铬不锈钢分为wc1=12％、wc1=17％和wc1=27％等种类；铬镍不锈钢中wc1=17％～20％，wni=8％～11％。铬镍不锈钢的抗腐蚀性能及力学性能比铬不锈钢高，     

N2O-C2H2火焰原子吸收光谱法测定高温镍基合金中钼

研究与运用N2O-C2H2火焰原子吸收光谱法进行高温镍基合金中含钼量的测定。介绍了钼最佳测定条件及呈良好线性范围的浓度。同时对样品消化处理条件及在测定中样品的干扰因素进行了综合考虑。其方法的相对标准偏差小于1．0％，回收率均在97．0％-100．0％范围内，适用于高温镍基合金中钼的分析。     

空气-乙炔火焰原子吸收光谱法快速测定纯镍中镁、锰、铁

提出了用空气-乙炔火焰原子吸收光谱法快速测定纯镍中镁、锰、铁含量，介绍了镁、锰、铁最佳测定条件及呈良好线性范围的浓度，在测定中对样品中的干扰因素进行了综合考虑。该方法具有很好的灵敏度和重现性，具有方法步骤简单、操作容易、干扰少等特点。测定样品中镁、锰、铁含量的相对标准偏差均小于1．0％。标准加入回收率均在97．0％～100．0％范围内。适用于纯镍中镁、锰、铁含量控制分析和样品系统分析。     

不锈钢的不同机加工方法

我们通常把含铬量≥11．7％或含镍〉8％的合金钢称为不锈钢。按化学成分可分为铬不锈钢和铬镍不锈钢,按使用状态下的金相组织组织可分马氏体不锈钢、铁素体不锈钢、奥氏体不锈钢、奥氏体＋铁素体不锈钢和沉淀硬化不锈钢。     

机电产品聚氯乙烯中铅、镉、铬、汞含量测定——发射光谱法

采用高温压力罐，将机电产品中的聚氯乙烯样品用硝酸．氟硼酸．过氧化氢溶解后，用全谱直读双向视电感耦合等离子体原子发射光谱仪（DUO-ICP-AES）同时测定聚氯乙烯中的铅、镉、铬和汞，方法的检测限为0．0015～0．014μg／mL，方法的回收率和精密度分别为87．7％～100．0％和0．12％～4．60％，实际样品的检测结果较为满意。该方法快速简便，可应用于机电产品密封外壳部件聚氯乙烯中的铅、镉、铬和汞日常检验。     

铬镍不锈钢铁磁性的分析

针对铬镍不锈钢是否具有铁磁性进行了分析和试验。结果表明，在平衡状态下及经塑性变形后，铬镍不锈钢都显现出铁磁性。     

高碘酸钾分光光度法测定火法冶炼镍基体料中锰

通过考察试料消解、波长选择、磷-高混酸比例及加入量、高碘酸钾加入量及煮沸时间、共存元素铁、铬、镍、钴干扰等试验条件,建立了高碘酸钾分光光度法测定火法冶炼镍基体料中锰的分析方法.样品回收率在99.5％～ 101％之间,精密度在1.0％以内,试料分析结果与ICP-AES法分析结果相符.该方法应用于火法冶炼镍基体料中锰的测定,精密度和准确度可满足实际测试工作的要求.     

微波消解-电感耦合等离子体质谱法同时测定聚氯乙烯塑料中的铅、镉、汞、铬

本文采用微波消解技术作为前处理手段，用电感耦合等离子体质谱（ICP-MS）法同时测定聚氯乙烯塑料中的铅、镉、汞、铬四种元素。对仪器的参数设置、样品的消解方法与体系进行了优化，为同类样品的分析提供了参考。方法检出限为1．4～7．2ng·g^-1，相对标准偏差为0．6～5．8％。     

电感耦合等离子体质谱法测定电子电气产品中Cr、Cd、Hg、Pb和Br

利用ICP-MS测定电子电气产品中镉、铬、铅、汞和溴。用高压微波消解技术处理样品，在消除Hg和Br的高记忆效应后，2，5％的硝酸介质下，上述元素的检测限（Cr，Cd，Hg，Pb）和Br分别为0．08 μg/L、6．0μg／L。样品的分析精密度（RSD％）小于5％和12％（Br）；标准加入回收率在80—134％之间。     

铬镍钼钛钢高温组织和高温性能研究

用高温短时拉伸试验和高温金相试验研究了某种铬镍钼钛钢的高温组织和高温性能。试验结果发现铬镍钼钛钢的强度值随着温度的升高逐渐降低，塑性值在700℃左右表现出一个低谷，之后大幅度升高。并用扫描电镜对每个温度的断口进行了形貌分析，结果发现，铬镍钼钛钢的高温短时拉伸断裂为典型的韧窝断裂。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.