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Research on overlaying welding rod of high hardness maraging steel

PAN Yong-ming, CHEN Shao-wei

《机械工程前沿（英文）》 2006年第1卷第4期页码 465-467 doi: 10.1007/s11465-006-0060-9

摘要： The development of new maraging steel overlaying welding rod, which contains Co, Mo, W and V alloy, solved the problems of poor homogeneity of hardness and mechanical process, prolonged the service life of wear-resistant components and increased the productive efficiency of repairing, greatly benefiting the national economy.

关键词： development productive efficiency national homogeneity mechanical

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Influence of pressure and density on the rheological properties of rockfills

Erich BAUER, Zhongzhi FU, Sihong LIU

《结构与土木工程前沿（英文）》 2012年第6卷第1期页码 25-34 doi: 10.1007/s11709-012-0143-0

摘要： Long-term deformations of rockfill dams can be related to the type of dam, the pre-compaction achieved during the construction of the dam, the history of loading events, the rheological properties of the rockfill material used, the seepage behavior caused by defects of the sealing, the interactions of the dam building with the foundation, and the hydrothermal phenomena of the stressed rockfill material. The present paper investigates the rheological properties of coarse grained rockfill materials using a hypoplastic constitutive model. Particular attention is paid to wetting deformation under different deviatoric loading states and pre-compactions. To quantify the state of weathering a so-called “solid hardness” is used in the sense of a continuum description. It is shown that an appropriate modeling of wetting deformations requires a unified description of the interaction at least between the state of weathering, the stress state, the density and the rate of deformation. The results obtained from the numerical simulations are compared with available experimental data for a rockfill material used in Xiaolangdi earth dam.

关键词： rockfills solid hardness wetting deformation hypoplasticity creep

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Development of soft kernel durum wheat

Craig F. MORRIS

《农业科学与工程前沿（英文）》 2019年第6卷第3期页码 273-278 doi: 10.15302/J-FASE-2019259

摘要：

Kernel texture (grain hardness) is a fundamental and determining factor related to wheat ( spp.) milling, baking and flour utilization. There are three kernel texture classes in wheat: soft and hard hexaploid ( ), and very hard durum ( subsp. ). The genetic basis for these three classes lies with the Puroindoline genes. Phenotypically, the easiest means of quantifying kernel texture is with the Single Kernel Characterization System (SKCS), although other means are valid and can provide fundamental material properties. Typical SKCS values for soft wheat would be around 25 and for durum wheat≥80. Soft kernel durum wheat was created via homeologous recombination using the mutation, which facilitated the transfer of ca. 28 Mbp of 5DS that replaced ca. 21 Mbp of 5BS. The 5DS translocation contained a complete and intact locus and both puroindoline genes. Expression of the puroindoline genes in durum grain resulted in kernel texture and flour milling characteristics nearly identical to that of soft wheat, with high yields of break and straight-grade flours, which had small particle size and low starch damage. Dough water absorption was markedly reduced compared to durum flour and semolina. Dough was essentially unchanged and reflected the inherent gluten properties of the durum background. Pasta quality was essentially equal-to-or-better than pasta made from semolina. Agronomically, soft durum germplasm showed good potential with moderate grain yield and resistance to a number of fungal pathogens and insects. Future breeding efforts will no doubt further improve the quality and competitiveness of soft durum cultivars.

关键词： soft durum wheat grain hardness puroindolines milling baking pasta noodles

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Evaluation of groundwater quality in the Xinjiang Plain Area

Jinlong ZHOU, Xinguang DONG, Yiping WANG, Guomin LI, Xiaojing GUO,

《环境科学与工程前沿（英文）》 2010年第4卷第2期页码 183-186 doi: 10.1007/s11783-010-0021-8

摘要： Groundwater is the main source of drinking water for the urban and rural residents in the plain area of the Xinjiang Uygur Autonomous Region, China. The quality of groundwater has a direct relationship with human health. Thus, 386 groundwater samples collected from April to August in 2003 were analyzed. The samples were collected in basic evaluation units which are determined on the basis of watersheds. Total dissolved solids, total hardness, pH value, NH–N, CHOH, Chemiluminescence detection of permanganate index (COD) and intestinal germ group were evaluated according to the guidelines of Groundwater Quality Standard (GB/T14848-93). The quality of the groundwater in each evaluation unit was classified by using the One Veto Method (a unified approach stipulated by the Ministry of Water Resources). The results indicate that the groundwater in the mainstream area of the Tarim Basin and the Yerqiang River Sub-basin belongs to Category V; the groundwater in the Wulungu River Sub-basin, the Kaidu-Kongque River Sub-basin, the Kashgar River Sub-basin, the Cherchen River Sub-basin and the Hotan River Sub-basin belongs to Category IV; the groundwater in the Aibi Lake System belongs to Category II, and the groundwater of other evaluation units belongs to Category III. The causes of water quality formation were concisely analyzed. The results can be useful for the evaluation and management of water resources in the Xinjiang Plain Area.

关键词： groundwater quality evaluation one veto method total dissolved solids (TDS) pH total hardness

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Hypoplastic constitutive modeling of wetting deformation of weathered rockfill materials

Erich BAUER, Zhongzhi FU, Sihong LIU,

《结构与土木工程前沿（英文）》 2010年第4卷第1期页码 78-91 doi: 10.1007/s11709-010-0011-8

摘要： The wetting deformation of weathered rockfill materials has been attracting growing attention from both engineers and scientists. The importance of realistic predictions of wetting deformations for high earth and rockfill dams is a strong motivation to establish a suitable constitutive model. Recently, the hypoplastic constitutive model by Gudehus and Bauer was extended by introducing solid hardness depending on the state of weathering. The extended model takes into account the influence of the current density, the effective stress state, the rate of deformation, and the time dependent process of degradation of the solid hardness. In the present paper, the performance of this model is evaluated by comparing numerical simulations with experiments obtained from a water sensitive rockfill material. In particular, triaxial compression paths and creep deformation under deviatoric stress states are considered. Finally, the constitutive model proposed is used to study the influence of a degradation of the solid hardness on the long term behavior of a hypothetical fill dam.

关键词： rockfill dams weathered granular materials hypoplasticity solid hardness creep stress relaxation

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装甲用镁合金抗弹性能表征体系探讨

才鸿年,谭成文,王富耻,陈志勇

《中国工程科学》 2006年第8卷第2期页码 30-33

摘要：

介绍了高应变率载荷条件下镁合金的吸能特性及变形特征；论述了对镁合金抗弹性能有重要影响的动态强度、高应变率能量吸收率、高应变率变形断裂特征和动态强度等科学问题；就镁合金在装甲领域的应用研究做了初步探讨。

关键词：能量吸收率绝热剪切变形局部化动态强度动态硬度

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Experimental study of surface integrity and fatigue life in the face milling of Inconel 718

Xiangyu WANG, Chuanzhen HUANG, Bin ZOU, Guoliang LIU, Hongtao ZHU, Jun WANG

《机械工程前沿（英文）》 2018年第13卷第2期页码 243-250 doi: 10.1007/s11465-018-0479-9

摘要：

The Inconel 718 alloy is widely used in the aerospace and power industries. The machining-induced surface integrity and fatigue life of this material are important factors for consideration due to high reliability and safety requirements. In this work, the milling of Inconel 718 was conducted at different cutting speeds and feed rates. Surface integrity and fatigue life were measured directly. The effects of cutting speed and feed rate on surface integrity and their further influences on fatigue life were analyzed. Within the chosen parameter range, the cutting speed barely affected the surface roughness, whereas the feed rate increased the surface roughness through the ideal residual height. The surface hardness increased as the cutting speed and feed rate increased. Tensile residual stress was observed on the machined surface, which showed improvement with the increasing feed rate. The cutting speed was not an influencing factor on fatigue life, but the feed rate affected fatigue life through the surface roughness. The high surface roughness resulting from the high feed rate could result in a high stress concentration factor and lead to a low fatigue life.

关键词： roughness hardness residual stress microstructure fatigue life

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激光熔覆NiCrAl-陶瓷涂层的显微组织研究

陈庆华,魏仑,龙晋明,李俊昌

《中国工程科学》 2001年第3卷第10期页码 64-71

摘要：

运用激光熔覆技术在40Cr钢表面制备了(TiO₂+B₂O₃+Al₂O₃+TiB₂)/NiCrAl金属陶瓷涂层，其中的TiB₂和Al₂O₃陶瓷颗粒在激光加工过程中原位反应生成；对熔覆层的组织、物相、元素分布和显微硬度分布特征进行了分析研究；熔覆层中的主相依次分别是γ-Ni,γ′,Al₂O₃和TiB₂，熔覆层的微观结构和硬度主要和激光处理参数和熔覆层化学组成有关^［1～9］；陶瓷相的原位生成和加入，大大改善了熔覆层的硬度和覆层/基体界面的结合性能。

关键词：激光熔覆金属陶瓷微观组织物相显微硬度

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铝合金板材拉伸变形时橘皮成因的研究进展

马鸣图,杨红亚,吴娥梅,金庆生

《中国工程科学》 2014年第16卷第1期页码 4-13

摘要：

本文对铝合金板材拉伸变形时橘皮成因的研究进展进行了评述。首先展示了有无橘皮板材在各种检测仪器下拉伸变形前后的表面形貌、表面滑移带、粗糙度和拉伸断口的形貌，并展示了纳米硬度的测量结果和表征。进一步介绍了最近关于橘皮形成的电子背散射衍射技术（EBSD）的研究成果和X射线对有无橘皮样品的织构测量结果，结合样品的显微组织和力学性能深入分析了橘皮的成因。一系列的结果表明，拉伸变形以后表面橘皮的出现与拉伸变形过程中产生的织构密切相关，而织构的生成又与拉伸过程中晶粒变形的不均匀性有关；晶粒的大小将明显影响变形的不均匀性和织构的生成，粗晶粒比细晶粒更容易产生不均匀变形、晶粒转动和织构，从而导致拉伸变形后生成表面橘皮。由此介绍了粗晶粒和细晶粒拉伸变形后表面状态的示意模型，同时建议对橘皮的形成进行进一步的研究和分析，以完善橘皮成因的定量描述。

关键词：橘皮成因力学性能拉伸断口纳米硬度 EBSD X射线

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TA2板料激光热应力弯曲成形及其力学性能研究

周益军,张永康,游文明

《中国工程科学》 2007年第9卷第10期页码 40-44

摘要：

用HVS-1000显微硬度测试仪、X-350A型X射线应力测定仪，以2.5 kW SM2000SM快轴流CO₂激光器对0.6 mm厚的TA2板料进行扫描，按照正交试验理论安排成形工艺参数，研究了TA2板料弯曲成形时主要工艺参数对弯曲角度的影响，以及试样表面残余应力的分布和试样断面上的显微硬度变化。结果表明：正交试验中的4个工艺参数的作用是不同的，按其变化对弯曲变形量影响的大小排序，依次是扫描次数、光斑直径、激光束功率、扫描速度；成形参数对试样表面的残余应力分布也存在一定的影响；试样变形区断面上的显微硬度变化呈现出一定的规律。

关键词：激光技术热应力板料弯曲成形残余应力显微硬度