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多孔结构设计人工踝关节衬垫生物力学的优化方案

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中国组织工程研究 2024年第30期28卷 4817-4824页

作者：徐志刘子铭李豫皖陈雨飞金瑛饶敬澄田守进张家港市第五人民医院骨科江苏省张家港市215600 北京大学第三医院运动医学科北京大学运动医学研究所运动医学关节伤病北京市重点实验室北京市100191 浙江大学医学院附属第一医院骨科浙江省杭州市310009 苏州市康力骨科器械有限公司江苏省张家港市215600 遵义医科大学附属医院骨科贵州省遵义市563000 徐州医科大学附属宿迁医院骨科江苏省宿迁市223800 苏州大学附属张家港医院骨科江苏省张家港市215600

背景:假体松动和磨损是导致全踝关节置换失败的主要原因,其与骨-植入物界面的微运动、关节面的接触应力和关节运动密切相关。包括衬垫和胫/距柄假体在内的人工关节部件的设计构造是影响踝关节受力、运动、接触界面微运动的关键因素,开... 详细信息

背景:假体松动和磨损是导致全踝关节置换失败的主要原因,其与骨-植入物界面的微运动、关节面的接触应力和关节运动密切相关。包括衬垫和胫/距柄假体在内的人工关节部件的设计构造是影响踝关节受力、运动、接触界面微运动的关键因素,开发新型衬垫对提高人工踝关节生存率具有重要意义。目的:构建全踝关节置换有限元模型用以检测多孔结构优化型衬垫的生物力学特性,分析多孔结构优化型衬垫在减少假体微动和改善关节面接触行为方面的作用。方法:以一名健康成年人右踝关节CT扫描数据和INBONEⅡ系统产品手册为基础,建立包括骨骼和人工关节系统的三维模型,在经过截骨和假体安装后获得全踝关节置换模型(模型A),再通过对原始衬垫进行多孔结构改造获得g50型、g60型、D50型、D60型4种新型衬垫,将不同衬垫替换原始衬垫以建立与之相对应的优化型全踝关节置换模型(模型B-E),在5个模型上施加步态载荷模拟步态工况。比较5种模型植入物-骨界面微动和关节面接触行为的差异。结果与结论:①在步态周期下4个优化型全踝关节置换模型的假体微动小于原始模型,与模型A相比,模型B-E假体微动数值上分别下降5.4%,10.1%,8.1%及20.9%,再者优化型模型在胫骨骨槽穹顶部的高微动区域较原始模型明显缩小;②4个优化型模型获得了更大的关节面接触面积,与模型A相比,模型B-E衬垫接触面积均值分别增加了11.8%,14.7%,8.1%及32.6%;③与接触面积增大的效果类似,相较于原始模型,优化型模型的关节面接触应力不同程度下降,其中模型E的数值下降最为显著(P<0.05),归功于构成D60型衬垫Diamond晶格良好的力学属性和较大的孔隙率;④结果表明全踝关节置换使用多孔结构改良衬垫可以提高衬垫的弹性,增加其吸收关节冲击力的能力,为降低植入物-骨界面微动和改善关节接触行为创造有利条件。

关键词：全踝关节置换人工踝关节衬垫多孔结构有限元分析

Impact of Cyclone Nilam on Tropical Lower Atmospheric Dynamics

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Advances in Atmospheric Sciences 2016年第8期33卷 955-968页

作者： P.VINAY KUMAR gopa DUTTA M.V.RATNAM E.KRISHNA B.BAPIRAJU B.venkateswara rao Salauddin MOHAMMAD Vignana Bharathi Institute of Technology HyderabadTS 501301India National Atmospheric Research Laboratory GadankiAP 517112India Jawaharlal Nehru Technological University HyderabadTS 500085India

A deep depression formed over the Bay of Bengal on 28 October 2012, and developed into a cyclonic storm. After landfall near the south coast of Chennai, cyclone Nilam moved north-northwestwards. Coordinated experiments were conducted from the Indian stations of gadanki（13.5？N, 79.2？E） and Hyderabad（17.4？N, 78.5？E） to study the modification of gravity-wave activity and turbulence by cyclone Nilam, using gPS radiosonde and mesosphere–stratosphere–troposphere radar data. The horizontal velocities underwent large changes during the closest approach of the storm to the experimental sites. Hodograph analysis revealed that inertia gravity waves（IgWs） associated with the cyclone changed their directions from northeast（control time） to northwest following the path of the cyclone. The momentum flux of IgWs and short-period gravity waves（1–8 h） enhanced prior to, and during, the passage of the storm（±0.05 m2s-2and ±0.3 m2s-2, respectively）, compared to the flux after its passage. The corresponding body forces underwent similar changes, with values ranging between ±2–4m s-1d-1and ±12–15 m s-1d-1. The turbulence refractivity structure constant（C2n） showed large values below 10 km before the passage of the cyclone when humidity in the region was very high. Turbulence and humidity reduced during the passage of the storm when a turbulent layer at ～17 km became more intense. Turbulence in the lower troposphere and near the tropopause became weak after the passage of the cyclone.

关键词： inertia gravity waves turbulence momentum flux convective process tropical cyclone

等离子弧熔覆Fe-C-B-V系耐磨堆焊层的组织及性能研究

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热加工工艺 2024年第2期53卷 145-148页

作者：刘畅饶嘉威蒋凤琦沈毅锋吴磊浦娟江苏科技大学材料科学与工程学院江苏镇江212000

以硼铁、高碳铬铁、钒铁为原料,采用等离子弧熔覆技术在Q345钢表面堆焊Fe-C-B-V系铁基合金。使用金相显微镜、扫描电镜和X射线衍射仪等研究了堆焊层的显微组织;分别使用维氏硬度计和冲击试验机测量堆焊层的显微硬度和冲击韧性。结果表明... 详细信息

以硼铁、高碳铬铁、钒铁为原料,采用等离子弧熔覆技术在Q345钢表面堆焊Fe-C-B-V系铁基合金。使用金相显微镜、扫描电镜和X射线衍射仪等研究了堆焊层的显微组织;分别使用维氏硬度计和冲击试验机测量堆焊层的显微硬度和冲击韧性。结果表明,堆焊层显微组织主要由马氏体、网格状Fe_(3)(C,B)和Fe_(2)B、弥散分布的碳化物及硼化物等(如VB_(2)、VC、Cr_(2)B)硬质相构成;堆焊层的平均硬度高达904.58 HV10、冲击功为68.5 J。堆焊过程中形成的硼化物、碳化物作为硬质相提高了堆焊层的硬度和耐磨性,形成的碳化钒使组织从鱼骨状变成网格状,细化了晶粒,提高了堆焊层的冲击韧性。

关键词：等离子熔覆 Fe-C-B-V堆焊层显微组织显微硬度冲击韧性

Multimodal Biometric Score Fusion Using gaussian Mixture Model and Monte Carlo Method

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Journal of Computer Science & Technology 2010年第4期25卷 771-782页

作者： R Raghavendra rao Ashok g Hemantha Kumar Department of Studies in Computer Science University of Mysore Department of E&C Channabasaveshwara Institute of Technology

Multimodal biometric fusion is gaining more attention among researchers in recent days. As multimodal biometric system consolidates the information from multiple biometric sources, the effective fusion of information obtained at score level is a challenging task. In this paper, we propose a framework for optimal fusion of match scores based on gaussian Mixture Mode] （gMM） and Monte Carlo sampling based hypothesis testing. The proposed fusion approach has the ability to handle： 1） small size of match scores as is more commonly encountered in biometric fusion, and 2） arbitrary distribution of match scores which is more pronounced when discrete scores and multimodal features are present. The proposed fusion scheme is compared with well established schemes such as Likelihood Ratio （LR） method and weighted SUM rule. Extensive experiments carried out on five different multimodal biometric databases indicate that the proposed fusion scheme achieves higher performance as compared with other contemporary state of art fusion techniques.

关键词： multimodal biometric system match score level fusion gaussian mixture model Monte Carlo method.

重覆冰区域风电送出线路中节能导线的应用研究

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电工电气 2024年第2期 30-34页

作者：曾祥耀饶玉凡中国能源建设集团湖南省电力设计院有限公司湖南长沙410007 长沙电力职业技术学院供电服务系湖南长沙410131

开展节能导线的应用研究,对重覆冰区域风电送出线路的安全、经济运行具有重要意义。以湖南某110 kV风电送出线路工程为例,针对其重覆冰、低损耗小时数的特点,从电能损耗、覆冰弧垂及过载能力、经济费用等方面对3类节能导线、钢芯铝合金... 详细信息

开展节能导线的应用研究,对重覆冰区域风电送出线路的安全、经济运行具有重要意义。以湖南某110 kV风电送出线路工程为例,针对其重覆冰、低损耗小时数的特点,从电能损耗、覆冰弧垂及过载能力、经济费用等方面对3类节能导线、钢芯铝合金绞线和普通钢芯铝绞线进行了应用分析。分析结果表明:在15 mm中冰区和20 mm重冰区,JL3/g1A-400/50型钢芯高导电率铝绞线更优;在30 mm重冰区,考虑弧垂特性和排杆需要,不适合采用节能导线,推荐采用钢芯铝合金绞线。

关键词：风电送出线路节能导线重覆冰区电能损耗弧垂特性

锌粉置换渣浸出过程中镓的溶解行为及改善方法

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Transactions of Nonferrous Metals Society of China 2024年第3期34卷 1016-1026页

作者：张伟饶帅李立清宫晓丹吴才贵胡东风曹洪杨刘志强江西理工大学材料冶金化学学部赣州341000 深圳市中金岭南有色金属股份有限公司丹霞冶炼厂韶关512325 广东省科学院资源利用与稀土开发研究所广州510650

针对丹霞冶炼厂锌粉置换渣浸出过程中镓浸出率偏低问题,采用ICP-AES、XRD与SEM-EDS对不同批次锌粉置换渣化学成分、物相与形貌进行详细分析。与正常生产锌粉置换渣相比,异常锌粉置换渣中镓主要赋存于黄钾铁矾之中,造成镓浸出困难。对锌... 详细信息

针对丹霞冶炼厂锌粉置换渣浸出过程中镓浸出率偏低问题,采用ICP-AES、XRD与SEM-EDS对不同批次锌粉置换渣化学成分、物相与形貌进行详细分析。与正常生产锌粉置换渣相比,异常锌粉置换渣中镓主要赋存于黄钾铁矾之中,造成镓浸出困难。对锌粉置换渣氧压浸出过程进行分析,镓、砷和铁溶出规律较为一致:增大硫酸浓度和液固比有利于镓、铁和砷的浸出,但提高温度和氧气分压对镓、铁和砷溶出不利。依据上述研究结果,提出强化镓浸出效率的改善措施,弱化一段氧压浸出(分别降低反应温度和压缩空气总压至90℃和0.2 MPa)与强化三段常压浸出(分别提高硫酸浓度和反应温度至160 g/L和85℃),镓的浸出效率由77.83%提高至96.46%。

关键词：溶解行为锌粉置换渣镓黄钾铁钒臭葱石

Enrichment of Nb and Ti from carbonatite pyrochlore ore via calcining-slaking followed by gravity separation

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International Journal of Mining Science and Technology 2022年第3期32卷 615-626页

作者： Shuhui Zhang Mingjun rao Rendong Xiao Jinxiang You guanghui Li Tao Jiang School of Minerals Processing&Bioengineering Central South UniversityChangsha 410083China

In this work,a novel process consisting of calcining-slaking followed by gravity separation for the enrichment of niobium(Nb)and titanium(Ti)from carbonatite pyrochlore ore was proposed,validated and compared with the current mainstream flotation *** calcining of the pyrochlore ore,within which the carbonates were transformed into ***,when the calcined ore was slaked,lime was transformed into hydroxide with fine particles which were amenable to gravity *** calcining at 900℃for 60 min,slaking at 90℃for 10 min with a liquid–solid ratio of 3:1(mL/g),approximately 40%of tailings can be removed by gravity separation,the recoveries of Nb and Ti were 94.7%and 91.0%,and the enrichment ratios of Nb and Ti were 1.61 and 1.43,*** new approach exhibits high separation efficiency of carbonate gangue minerals and valuable minerals,satisfactory recoveries of niobium as well as titanium can be achieved.

关键词： Niobium Titanium Pyrochlore ore Calcination gravity separation

In situ kinetics and flocs conformation studies of kaolinite flocculated by Chi-g-CPAM

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International Journal of Minerals,Metallurgy and Materials 2023年第5期30卷 813-823页

作者： Ruijing Xu Wenjie Zou Bo rao Wei Zhao Ting Wang Zhijun Zhang State Key Laboratory of High-Efficient Mining and Safety of Metal Mines of Ministry of Education University of Science and Technology BeijingBeijing 100083China School of Civil and Resources Engineering University of Science and Technology BeijingBeijing 100083China School of Chemical and Environmental Engineering China University of Mining and TechnologyBeijing 100083China

This study presents a comparative study of the flocculation behavior of kaolinite induced by chitosan-graft-poly(acrylamide-dimethyl diallyl ammonium chloride)(Chi-g-CPAM) and a commercial cationic polyacrylamide(CPAM).The flocculation behaviour was characterised in terms of both flocculation kinetics and the corresponding morphology changes during *** Chi-g-CPAM and CPAM were grafted from silica wafers by means of atom transfer radical polymerization(ATRP).The quartz crystal microbalance with dissipation(QCM-D) tests were *** equilibrium time flocculated by Chi-g-CPAM was found to be 0.46 times as that of CPAM,together with a larger total mass of kaolinite *** flocculation behaviour by Chi-g-CPAM can be well captured by a pseudo-first-order *** contrast,the presence of CPAM leads to a more complex kinetics.A relatively larger fitting slope(0.4663) was obtained at the initial stage but the fitting slope droped to 0.2026 after 800 min,indicating a densification process caused by *** flocculation kinetics of CPAM can be captured by the Elovich model for the inital stage but the combination of pseudo-first-order and pseudo-second-order models for the latter stages,which can be attributed to the long chain of *** a dosage of 75 g/t,the settling test with Chi-g-CPAM exhibits the same turbidity in the supernatant but a smaller layer thickness of the settlement compared to *** study enables a better understanding of the flocculation behavior and contributes to the development of efficient flocculants in mineral processing and tailings treatment.

关键词： Chi-g-CPAM flocculation QCM-D kinetics conformation

Influence of Rotational Speed on Microstructure and Mechanical Properties of Dissimilar Metal AISI 304-AISI 4140 Continuous Drive Friction Welds

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Journal of Iron and Steel Research(International) 2012年第10期19卷 64-73页

作者： g Subhash Chander g Madhusudhan Reddy A Venugopal rao Swarna Bharathi Institute of Science and Technology Khammam 507002APIndia Defense Metallurgical Research Laboratory Kanchanbagh 500058APIndia

Fundamental investigation of continuous drive friction welding of austenitic stainless steel (AISI 304) and low alloy steel (AISI 4140) is described. The emphasis is made on the influence of rotational speed on the microstructure and mechanical properties such as hardness, tensile strength, notch tensile strength and impact toughness of the dissimilar joints. Hardness profiles across the weld show the interface is harder than the respective parent metals. In general, maximum peak hardness is observed on the stainless steel side, while other peak hardness is on the low alloy steel side. A trough in hardness distribution in between the peaks is located on the low alloy steel side. Peak hardness on the stainless steel and low alloy steel side close to the interface increases with a decrease in rotational speed. All transverse tensile joints fractured on stainless steel side near the interface. Notch tensile strength and impact toughness increase with increase in rotational speed up to 1 500 r/min and decrease thereafter. The mechanism of influence of rotational speed for the observed trends is discussed in the torque, displacement characteristics, heat generation, microstructure, fractography and mechanical properties.

关键词： friction welding dissimilar metal joint austenitic stainless steel low alloy steel microstructure impact toughness tensile strength