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Region-Aware Fashion Contrastive Learning for Unified Attribute Recognition and Composed Retrieval
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作者 WANG Kangping ZHAO Mingbo 《Journal of Donghua University(English Edition)》 CAS 2024年第4期405-415,共11页
Clothing attribute recognition has become an essential technology,which enables users to automatically identify the characteristics of clothes and search for clothing images with similar attributes.However,existing me... Clothing attribute recognition has become an essential technology,which enables users to automatically identify the characteristics of clothes and search for clothing images with similar attributes.However,existing methods cannot recognize newly added attributes and may fail to capture region-level visual features.To address the aforementioned issues,a region-aware fashion contrastive language-image pre-training(RaF-CLIP)model was proposed.This model aligned cropped and segmented images with category and multiple fine-grained attribute texts,achieving the matching of fashion region and corresponding texts through contrastive learning.Clothing retrieval found suitable clothing based on the user-specified clothing categories and attributes,and to further improve the accuracy of retrieval,an attribute-guided composed network(AGCN)as an additional component on RaF-CLIP was introduced,specifically designed for composed image retrieval.This task aimed to modify the reference image based on textual expressions to retrieve the expected target.By adopting a transformer-based bidirectional attention and gating mechanism,it realized the fusion and selection of image features and attribute text features.Experimental results show that the proposed model achieves a mean precision of 0.6633 for attribute recognition tasks and a recall@10(recall@k is defined as the percentage of correct samples appearing in the top k retrieval results)of 39.18 for composed image retrieval task,satisfying user needs for freely searching for clothing through images and texts. 展开更多
关键词 attribute recognition image retrieval contrastive language-image pre-training(CLIP) image text matching transformer
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Deep learning-based recognition of stained tongue coating images
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作者 ZHONG Liqin XIN Guojiang +3 位作者 PENG Qinghua CUI Ji ZHU Lei LIANG Hao 《Digital Chinese Medicine》 CAS CSCD 2024年第2期129-136,共8页
Objective To build a dataset encompassing a large number of stained tongue coating images and process it using deep learning to automatically recognize stained tongue coating images.Methods A total of 1001 images of s... Objective To build a dataset encompassing a large number of stained tongue coating images and process it using deep learning to automatically recognize stained tongue coating images.Methods A total of 1001 images of stained tongue coating from healthy students at Hunan University of Chinese Medicine and 1007 images of pathological(non-stained)tongue coat-ing from hospitalized patients at The First Hospital of Hunan University of Chinese Medicine withlungcancer;diabetes;andhypertensionwerecollected.Thetongueimageswererandomi-zed into the training;validation;and testing datasets in a 7:2:1 ratio.A deep learning model was constructed using the ResNet50 for recognizing stained tongue coating in the training and validation datasets.The training period was 90 epochs.The model’s performance was evaluated by its accuracy;loss curve;recall;F1 score;confusion matrix;receiver operating characteristic(ROC)curve;and precision-recall(PR)curve in the tasks of predicting stained tongue coating images in the testing dataset.The accuracy of the deep learning model was compared with that of attending physicians of traditional Chinese medicine(TCM).Results The training results showed that after 90 epochs;the model presented an excellent classification performance.The loss curve and accuracy were stable;showing no signs of overfitting.The model achieved an accuracy;recall;and F1 score of 92%;91%;and 92%;re-spectively.The confusion matrix revealed an accuracy of 92%for the model and 69%for TCM practitioners.The areas under the ROC and PR curves were 0.97 and 0.95;respectively.Conclusion The deep learning model constructed using ResNet50 can effectively recognize stained coating images with greater accuracy than visual inspection of TCM practitioners.This model has the potential to assist doctors in identifying false tongue coating and prevent-ing misdiagnosis. 展开更多
关键词 Deep learning Tongue coating Stained coating Image recognition Traditional Chinese medicine(TCM) Intelligent diagnosis
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Design and characterization of biodegradable Mg-Zn-Ag metallic glasses
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作者 Jian WANG Chen WANG +1 位作者 Wei-feng RAO In-ho JUNG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第9期2814-2827,共14页
In order to develop the Mg-Zn-Ag metallic glasses(MGs)for biodegradable implant applications,the glass formation ability(GFA)and biocompatibility of Mg-Zn-Ag alloys were investigated using a combination of the calcula... In order to develop the Mg-Zn-Ag metallic glasses(MGs)for biodegradable implant applications,the glass formation ability(GFA)and biocompatibility of Mg-Zn-Ag alloys were investigated using a combination of the calculation of phase diagrams(CALPHAD)and experimental measurements.High GFA potentiality of two alloy series,specifically Mg_(96-x)Zn_xAg_(4)and Mg_(94-x)Zn_xAg_6(x=17,20,23,26,29,32,35),was predicted theoretically and then substantiated through experimental testing.X-ray diffraction(XRD)and differential scanning calorimetry(DSC)techniques were used to evaluate the crystallinity,GFA,and crystallization characteristics of these alloys.The results showed that compositions between Mg_(73)Zn_(23)Ag_(4)and Mg_(64)Zn_(32)Ag_(4)for Mg_(96-x)Zn_xAg_4,Mg_(66)Zn_(28)Ag_(6)and Mg_(63)Zn_(31)Ag_(6for)Mg_(94-x)Zn_xAg_(6)displayed a superior GFA.Notably,the GFA of the Mg_(96-x)Zn_xAg_(4)series was better than that of the Mg_(94-x)Zn_xAg_(6)series.Furthermore,the Mg_(70)Zn_(26)Ag_4,Mg_(74)Zn_(20)Ag_6,and Mg_(71)Zn_(23)Ag_(6)alloys showed acceptable corrosion rates,good cytocompatibility,and positive effects on cell proliferation.These characteristics make them suitable for applications in medical settings,potentially materials as biodegradable implants. 展开更多
关键词 glass forming ability calculation phase diagram(CALPHAD) Mg−Zn−Ag metallic glasses CYTOCOMPATIBILITY
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Research on the LA-UMamba Model for Asymmetric Modules with Added Auxiliary Information
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作者 YAN Jing SI Zhan-jun ZHANG Ying-xue 《印刷与数字媒体技术研究》 CAS 北大核心 2024年第4期56-66,共11页
Deep learning techniques are revolutionizing the developmentof medical image segmentation.With the advancement of Transformer models,especially ViT and Swin-Transformer,which enhances the remote-dependent modeling cap... Deep learning techniques are revolutionizing the developmentof medical image segmentation.With the advancement of Transformer models,especially ViT and Swin-Transformer,which enhances the remote-dependent modeling capability of the model through the self-attention mechanism,better segmentation performance can be achieve.Moreover,the high computational cost of Transformer has motivated researchers to explore more efficient models,such as the Mamba model based on state-space modeling(SSM),and for the field of medical segmentation,reducing the number of model parameters is also necessary.In this study,a novel asymmetric model called LA-UMamba was proposed,which integrates visual Mamba module to efficiently capture complex visual features and remote dependencies.The classical design of U-Net was adopted in the upsampling phase to help reduce the number of references and recover more details.To mitigate the information loss problem,an auxiliary U-Net downsampling layer was designed to focus on sizing without extracting features,thus enhancing the protection of input information while maintaining the efficiency of the model.The experiments were conducted on the ACDC MRI cardiac segmentation dataset,and the results showed that the proposed LA-UMamba achieves proved performance compared to the baseline model in several evaluation metrics,such as IoU,Accuracy,Precision,HD and ASD,which improved that the model is successful in optimizing the detail processing and reducing the complexity of the model,providing a new perspective for further optimization of medical image segmentation techniques. 展开更多
关键词 Medical image segmentation U-Net Mamba module Deep Learning
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State Estimation Method for GNSS/INS/Visual Multi-sensor Fusion Based on Factor Graph Optimization for Unmanned System
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作者 ZHU Zekun YANG Zhong +2 位作者 XUE Bayang ZHANG Chi YANG Xin 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2024年第S01期43-51,共9页
With the development of unmanned driving technology,intelligent robots and drones,high-precision localization,navigation and state estimation technologies have also made great progress.Traditional global navigation sa... With the development of unmanned driving technology,intelligent robots and drones,high-precision localization,navigation and state estimation technologies have also made great progress.Traditional global navigation satellite system/inertial navigation system(GNSS/INS)integrated navigation systems can provide high-precision navigation information continuously.However,when this system is applied to indoor or GNSS-denied environments,such as outdoor substations with strong electromagnetic interference and complex dense spaces,it is often unable to obtain high-precision GNSS positioning data.The positioning and orientation errors will diverge and accumulate rapidly,which cannot meet the high-precision localization requirements in large-scale and long-distance navigation scenarios.This paper proposes a method of high-precision state estimation with fusion of GNSS/INS/Vision using a nonlinear optimizer factor graph optimization as the basis for multi-source optimization.Through the collected experimental data and simulation results,this system shows good performance in the indoor environment and the environment with partial GNSS signal loss. 展开更多
关键词 state estimation multi-sensor fusion combined navigation factor graph optimization complex environments
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A Cognitive Study on Politeness Intention Processing and Its Association with Pragmatic Failure in Cross-Cultural Communication
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作者 Rong YAN Tengfei FENG Samad ZARE 《Chinese Journal of Applied Linguistics》 2024年第3期481-497,525,共18页
Although a large number of studies have focused on various aspects of politeness,very little is known about how politeness intention is activated cognitively during verbal communication.The present study aims to explo... Although a large number of studies have focused on various aspects of politeness,very little is known about how politeness intention is activated cognitively during verbal communication.The present study aims to explore the cognitive mechanism of politeness intention processing,and how it is related to pragmatic failure during cross-cultural communication.Using 30 Chinese EFL university students who were instructed to finish a probe word judgment task with 96 virtual scenarios,the results indicate that within both mono-and cross-cultural contexts,the response time in the experimental scenarios was significantly slower than that of the filler scenarios.This suggests that politeness intention was activated while understanding the surface meaning of the conversation;however,the EFL learners could not completely avoid the negative transfer of their native politeness conventions when they were comprehending the conversational intention of the target language.Furthermore,no significant differences in response time were found between the groups with high and low English pragmatic competence,illustrating that transferring the pragmatic rules and principles into cross-cultural communication skills was more cognitively demanding.Overall,this study adds to the literature on politeness research and provides some implications for foreign language pragmatic instructions. 展开更多
关键词 politeness intention cognitive processing pragmatic failure cross-cultural pragmatics cross-cultural communication
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《大金德运图说》所见金朝后期日常中枢政务运作
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作者 田晓雷 《史学集刊》 北大核心 2024年第4期83-91,共9页
《大金德运图说》所录“省判”应为尚书都省誊写的礼部呈录文。其所录省劄的正文并无“奉圣旨”或与之类似的文字,这是金朝后期尚书都省肆意以省劄指挥政务的表现。这反映了宣宗初年宰执施政空间的扩大和对皇权行使的牵制。《大金德运... 《大金德运图说》所录“省判”应为尚书都省誊写的礼部呈录文。其所录省劄的正文并无“奉圣旨”或与之类似的文字,这是金朝后期尚书都省肆意以省劄指挥政务的表现。这反映了宣宗初年宰执施政空间的扩大和对皇权行使的牵制。《大金德运图说》所载尚书省“议”的性质类似于尚书都省的存档备查文书。从《大金德运图说》所录诸文来看,金朝后期中枢政令的下达渠道有皇帝颁发圣旨和尚书都省下发省劄,以及执行政务的主管机构发送相应的政令文书、官员通过所属或主管机构的公开榜文接到政令等多种途径。皇权对政务的最终决策通过行文格式得到认可,同时金朝后期宰执独立处理政务的空间仍然存在。这虽然没有从根本上动摇和架空皇权,但是的确限制了皇权的向下延伸。 展开更多
关键词 《大金德运说》 省劄 文书 中枢政务
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高校图书馆参与第一代大学生支持服务的经验及启示——基于美国研究型大学图书馆的调查分析 被引量:1
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作者 马迪倩 《大学图书馆学报》 北大核心 2023年第6期107-116,共10页
我国高等教育进入普及化发展阶段,第一代大学生在校占比持续上升且受先赋性不利因素的影响,在学业、社交、校园生活等方面表现不足,部分教育收获较低。高校图书馆的适时介入与助推可显著减少高等教育对该群体的无效供给,有效改善其大学... 我国高等教育进入普及化发展阶段,第一代大学生在校占比持续上升且受先赋性不利因素的影响,在学业、社交、校园生活等方面表现不足,部分教育收获较低。高校图书馆的适时介入与助推可显著减少高等教育对该群体的无效供给,有效改善其大学体验感和受教育经历。文章以美国研究型大学图书馆为研究对象,运用系统性文献研究方法,从Web of Science核心合集和中国知网(CNKI)检索文献中梳理美国图书馆学界参与校园支持的研究进展;运用网络调研方法,调查美国13所研究型大学图书馆的服务举措。立足我国第一代大学生非经济因素群体困境,借鉴国外图书馆的支持理念和服务经验,建议我国“211工程”和“985工程”高校图书馆从减少服务障碍、搭建同伴支持平台、尽早开展信息素养和财经素养教育以及合作组织高影响力教育活动5个途径开展支持服务,以融入大学“三全育人”体系,助力大学生成长成才、促进教育公平和高质量发展。 展开更多
关键词 第一代大学生 高校书馆 协同育人 学生成功
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一类双圈图匹配多项式的最大根 被引量:4
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作者 马海成 李丹阳 《广州大学学报(自然科学版)》 CAS 2020年第1期72-77,共6页
设G是有n个点的图,恰有n-1、n和n+1条边的连通图分别称为树、单圈图和双圈图.文章给出了包含一个∞-图为其导出子图的一类双圈图匹配多项式的最大根的取值范围,以及达到极值的图.
关键词 ∞-图 双圈 匹配多项式 最大根
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A fracture enhancement method based on the histogram equalization of eigenstructure-based coherence 被引量:7
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作者 窦喜英 韩立国 +3 位作者 王恩利 董雪华 杨庆 鄢高韩 《Applied Geophysics》 SCIE CSCD 2014年第2期179-185,253,共8页
Eigenstructure-based coherence attributes are efficient and mature techniques for large-scale fracture detection. However, in horizontally bedded and continuous strata, buried fractures in high grayscale value zones a... Eigenstructure-based coherence attributes are efficient and mature techniques for large-scale fracture detection. However, in horizontally bedded and continuous strata, buried fractures in high grayscale value zones are difficult to detect. Furthermore, middleand small-scale fractures in fractured zones where migration image energies are usually not concentrated perfectly are also hard to detect because of the fuzzy, clouded shadows owing to low grayscale values. A new fracture enhancement method combined with histogram equalization is proposed to solve these problems. With this method, the contrast between discontinuities and background in coherence images is increased, linear structures are highlighted by stepwise adjustment of the threshold of the coherence image, and fractures are detected at different scales. Application of the method shows that it can also improve fracture cognition and accuracy. 展开更多
关键词 FAULT FRACTURE histogram equalization COHERENCE ENHANCEMENT
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Hot deformation behavior of TC11/Ti-22Al-25Nb dual-alloy in isothermal compression 被引量:7
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作者 秦春 姚泽坤 +2 位作者 宁永权 石志峰 郭鸿镇 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第7期2195-2205,共11页
The high-temperature flow behavior of TCll/Ti-22Al-25 Nb electron beam(EB) weldments was investigated by the isothermal compression tests at the temperature of 900-1060℃ and the strain rate of 0.001-10 s-(-1).Bas... The high-temperature flow behavior of TCll/Ti-22Al-25 Nb electron beam(EB) weldments was investigated by the isothermal compression tests at the temperature of 900-1060℃ and the strain rate of 0.001-10 s-(-1).Based on the experimental data,the constitutive equation that describes the flow stress as a function of strain rate and deformation temperature is obtained.The apparent activation energy of deformation is calculated,which decreases with increasing the strain and the value is 334 kJ/mol at strain of 0.90.The efficiency of power dissipation η changes obviously with the variation of deformation conditions.Under the strain rates of 0.01,0.1 and 1 s-(-1),the value of η increases with increasing the true strain for different deformation temperatures.While the value of η decreases with increasing the strain under the strain rates of 0.001 and 10 s-(-1).The optimum processing condition is(t(opi)=1060℃,ε(opi)=0.1 s-(-1)) with the peak efficiency of 0.51.Under this deformation,dynamic recrystallization(DRX) is observed obviously in the microstructure of welding zone.Under the condition of 1060℃ and 0.001 s-(-1),the deformation mechanism is dominated by dynamic recovery(DRV) and the value of η decreases sharply(η=0.02).The flow instability is predicted to occur since the instability parameter ξ(ε)becomes negative.The hot working process can be carried out safely in the domain with the strain rate of 0.001-0.6 s-(-1) and the temperature of 900-1060℃. 展开更多
关键词 dual-alloy hot deformation processing map apparent activation energy MICROSTRUCTURE
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Thermodynamic calculation of high zinc-containing Al-Zn-Mg-Cu alloy 被引量:9
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作者 刘俊涛 张永安 +3 位作者 李锡武 李志辉 熊柏青 张济山 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第5期1481-1487,共7页
Phase fraction and solidification path of high Zn-containing Al-Zn-Mg-Cu series aluminum alloy were calculated by calculation of phase diagram (CALPHAD) method. Microstructure and phases of Al-9.2Zn-1.7Mg-2.3Cu allo... Phase fraction and solidification path of high Zn-containing Al-Zn-Mg-Cu series aluminum alloy were calculated by calculation of phase diagram (CALPHAD) method. Microstructure and phases of Al-9.2Zn-1.7Mg-2.3Cu alloy were studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The calculation results show that η(MgZn2) phase is influenced by Zn and Mg. Mass fractions of η(MgZn2) in Al-xZn-1.7Mg-2.3Cu are 10.0%, 9.8% and 9.2% for x=9.6, 9.4, 8.8 (mass fraction, %), respectively. The intervals of Mg composition were achieved for θ(Al2Cu)+η(MgZn2), S(Al2CuMg)+η(MgZn2) and θ(Al2Cu)+S(Al2CuMg)+η(MgZn2) phase regions. Al3Zr, α(Al), Al13Fe4, η(MgZn2), α-AlFeSi, Al7Cu2Fe, θ(Al2Cu), Al5Cu2MgsSi6 precipitate in sequence by no-equilibrium calculation. The SEM and XRD analyses reveal that α(Al), η(MgZn2), Mg(Al,Cu,Zn)2, θ(Al2Cu) and Al7Cu2Fe phases are discovered in Al-9.2Zn-1.7Mg-2.3Cu alloy. The thermodynamic calculation can be used to predict the major phases present in experiment. 展开更多
关键词 thermodynamic calculation high-zinc alloy AL-ZN-MG-CU calculation of phase diagram (CALPHAD)
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Hot deformation behavior of novel imitation-gold copper alloy 被引量:7
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作者 朱安印 陈景林 +4 位作者 李周 罗利阳 雷前 张良 张婉 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第5期1349-1355,共7页
The hot deformation behavior of a novel imitation-gold copper alloy was investigated with Gleeble-1500 thermo-mechanical simulator in the temperature range of 650-770 °C and strain rate range of 0.001-1.0 s-1. Th... The hot deformation behavior of a novel imitation-gold copper alloy was investigated with Gleeble-1500 thermo-mechanical simulator in the temperature range of 650-770 °C and strain rate range of 0.001-1.0 s-1. The hot deformation constitutive equation was established and the thermal activation energy was obtained to be 249.60 kJ/mol. The processing map at a strain of 1.2 was developed. And there are two optimal regions in processing map, namely 650-680 °C, 0.001-0.01 s-1 and 740-770 °C, 0.01-0.1 s-1. Optical microscopy was employed to investigate the microstructure evolution of the alloy in the process of deformation. Recrystallized grains and twin crystals were found in microstructures of the hot deformed alloy. 展开更多
关键词 imitation-gold alloy hot compression deformation constitutive equation processing map
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Hot deformation behavior of as-quenched 7005 aluminum alloy 被引量:7
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作者 王明亮 金培鹏 +1 位作者 王金辉 韩丽 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第9期2796-2804,共9页
The compressive deformation behavior of as-quenched 7005 aluminum alloy was investigated at the temperature ranging from 250 °C to 450 °C and strain rate ranging from 0.0005 s-1 to 0.5 s^-1 on Gleeble-1500 t... The compressive deformation behavior of as-quenched 7005 aluminum alloy was investigated at the temperature ranging from 250 °C to 450 °C and strain rate ranging from 0.0005 s-1 to 0.5 s^-1 on Gleeble-1500 thermal-simulation machine. Experimental results show that the flow stress of as-quenched 7005 alloy is affected by both deformation temperature and strain rate, which can be represented by a Zener-Hollomon parameter in an exponent-type equation. By comparing the calculated flow stress and the measured flow stress, the results show that the calculated flow stress agrees well with the experimental result. Based on a dynamic material model, the processing maps were constructed for the strains of 0.1, 0.3 and 0.5. The maps and microstructural examination revealed that the optimum hot working domain is 270-340 °C, 0.05-0.5 s^-1 with the reasonable dynamic recrystallization. The instability domain exhibits adiabatic shear bands and flow localization, which should be avoided during hot working in order to obtain satisfactory properties. 展开更多
关键词 7005 alloy hot compression deformation constitutive equation processing map
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Determination of local constitutive behavior and simulation on tensile test of 2219-T87 aluminum alloy GTAW joints 被引量:6
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作者 李艳军 李权 +5 位作者 吴爱萍 麻宁绪 王国庆 Hidekazu MURAKAWA 鄢东洋 吴会强 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第9期3072-3079,共8页
The local and global mechanical responses of gas tungsten arc welds(GTAW) of a 2219-T87 aluminum alloy were investigated with experiment and numerical simulation.Digital image correlation(DIC) was used to access t... The local and global mechanical responses of gas tungsten arc welds(GTAW) of a 2219-T87 aluminum alloy were investigated with experiment and numerical simulation.Digital image correlation(DIC) was used to access the local strain fields in transversely loaded welds and to determine the local stress-strain curves of various regions in the joint.The results show that the DIC method is efficient to acquire the local stress-strain curves but the curves of harder regions are incomplete because the stress and strain ranges are limited by the weakest region.With appropriate extrapolation,the complete local stress-strain curves were acquired and proved to be effective to predict the tensile behavior of the welded joint.During the tensile process,the fracture initiates from the weld toes owing to their plastic strain concentrations and then propagates along the fusion line,finally propagates into the partially melted zone(PMZ). 展开更多
关键词 aluminum alloy tensile behavior digital image correlation constitutive behavior welded joint
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Constitutive equation and processing map for hot compressed as-cast Ti-43Al-4Nb-1.4W-0.6B alloy 被引量:5
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作者 李建波 刘咏 +3 位作者 王岩 刘彬 卢斌 梁霄鹏 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第11期3383-3391,共9页
High temperature compressive deformation behaviors of as-cast Ti-43Al-4Nb-1.4W-0.6B alloy was investigated at temperatures ranging from 1323 K to 1473 K, and strain rates from 0.001 s-1 to 1 s-1. The results indicated... High temperature compressive deformation behaviors of as-cast Ti-43Al-4Nb-1.4W-0.6B alloy was investigated at temperatures ranging from 1323 K to 1473 K, and strain rates from 0.001 s-1 to 1 s-1. The results indicated that the true stress-true strain curves show a dynamic flow softening behavior. The flow curves after the friction and the temperature compensations were employed to develop constitutive equations. The effects of temperature and the strain rate on the deformation behavior were represented by Zener-Holloman exponential equation. The influence of strain was incorporated in the constitutive analysis by considering the effect of the strain on material constants by a five-order polynomial. A revised model was proposed to describe the relationships among the flow stress, strain rate and temperature and the predicted flow stress curves were in good agreement with experimental results. Appropriate deformation processing parameters were suggested based on the processing map which was constructed from friction and temperature corrected flow curves, determined as 1343 K, 0.02 s-1 and were successfully applied in the canned forging of billets to simulate industrial work condition. 展开更多
关键词 TiAl alloy flow stress hot deformation constitutive equation processing map
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φ-pH diagram of V-Ti-H_2O system during pressure acid leaching of converter slag containing vanadium and titanium 被引量:4
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作者 牟望重 张廷安 +2 位作者 豆志河 吕国志 刘燕 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第9期2078-2086,共9页
To analyze the thermodynamic characteristics of leaching process of converter slag, φ-pH diagram of V-Ti-H2O system at oxygen partial pressure of 0.5 MPa, ionic mass concentration of 0.1 mol/kg and temperatures rangi... To analyze the thermodynamic characteristics of leaching process of converter slag, φ-pH diagram of V-Ti-H2O system at oxygen partial pressure of 0.5 MPa, ionic mass concentration of 0.1 mol/kg and temperatures ranging from 60 to 200 ℃ was obtained by recently published critically assessed standard Gibbs energies and activity coefficients of various species. When pH2, stable regions of V3+, VO2+ and VO2+ exist in the stable region of TiO2. The pH values of stable regions of vanadium and titanium decrease and redox potentials become more positive with the temperature increasing. Vanadium and titanium could be separated by one-step leaching based on thermodynamics. The experiment results of pressure acid leaching of converter slag show that leaching rates of vanadium and titanium are 96.87% and 8.76% respectively, at 140 ℃ of temperature, 0.5 MPa of oxygen partial pressure, 0.055-0.075mm of particle size, 15:1 of liquid to solid ratio, 120 min of leaching time, 500 r/min of stirring speed and 200 g/L of initial acid concentration. Vanadium and titanium could be selectively separated in the pressure acid leaching process, and the experiment result is in agreement with thermodynamic calculation result. 展开更多
关键词 φ-pH diagram V-Ti-H2O system pressure acid leaching converter slag VANADIUM titanium
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Processing map and hot deformation mechanism of novel nickel-free white copper alloy 被引量:7
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作者 刘娜 李周 +2 位作者 李灵 刘斌 徐根应 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第11期3492-3499,共8页
Hot compression test of a novel nickel-free white alloy Cu?12Mn?15Zn?1.5Al?0.3Ti?0.14B?0.1Ce (mass fraction, %) was conducted on a Gleeble?1500 machine in the temperature range of 600?800 °C and the strain rate r... Hot compression test of a novel nickel-free white alloy Cu?12Mn?15Zn?1.5Al?0.3Ti?0.14B?0.1Ce (mass fraction, %) was conducted on a Gleeble?1500 machine in the temperature range of 600?800 °C and the strain rate range of 0.01?10 s?1. The constitutive equation and hot processing map of the alloy were built up according to its hot deformation behavior and hot working characteristics. The deformation activation energy of the alloy is 203.005 kJ/mol. An instability region appears in the hot deformation temperature of 600?700 °C and the strain rate range of 0.32?10 s?1 when the true strain of the alloy is up to 0.7. Under the optimal hot deformation condition of 800 °C and 10 s?1 the prepared specimen has good surface quality and interior structure. The designed nickel-free alloy has very similar white chromaticity with the traditional white copper alloy (Cu?15Ni?24Zn?1.5Pb), and the color difference between them is less than 1.5, which can hardly be distinguished by human eyes. 展开更多
关键词 Ni-free white copper alloy hot compression deformation constitutive equation processing map
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First-principles thermodynamics of metal-oxide surfaces andinterfaces:A case study review 被引量:4
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作者 江勇 许灿辉 蓝国强 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第1期180-192,共13页
An important step for achieving the knowledge-based design freedom on nano-and interfacial materials is attained by elucidating the related surface and interface thermodynamics from the first principles so as to allow... An important step for achieving the knowledge-based design freedom on nano-and interfacial materials is attained by elucidating the related surface and interface thermodynamics from the first principles so as to allow engineering the microstructures for desired properties through smartly designing fabrication processing parameters.This is demonstrated for SnO2 nano-particle surfaces and also a technologically important Ag-SnO2 interface fabricated by in-situ internal oxidation.Based on defect thermodynamics,we first modeled and calculated the equilibrium surface and interface structures,and as well corresponding properties,as a function of the ambient temperature and oxygen partial pressure.A series of first principles energetics calculations were then performed to construct the equilibrium surface and interface phase diagrams,to describe the environment dependence of the microstructures and properties of the surfaces and interfaces during fabrication and service conditions.The use and potential application of these phase diagrams as a process design tool were suggested and discussed. 展开更多
关键词 metal oxide surface phase diagram interface phase diagram equilibrium crystal shape FIRST-PRINCIPLES THERMODYNAMICS
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Hot deformation behavior of Al-9.0Mg-0.5Mn-0.1Ti alloy based on processing maps 被引量:7
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作者 范才河 彭英彪 +2 位作者 阳海棠 周伟 严红革 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2017年第2期289-297,共9页
Hot deformation behavior of extrusion preform of the spray-formed Al-9.0Mg-0.5Mn-0.1Ti alloy was studied using hot compression tests over deformation temperature range of 300-450 ℃ and strain rate range of 0.01... Hot deformation behavior of extrusion preform of the spray-formed Al-9.0Mg-0.5Mn-0.1Ti alloy was studied using hot compression tests over deformation temperature range of 300-450 ℃ and strain rate range of 0.01-10 s-1. On the basis of experiments and dynamic material model, 2D processing maps and 3D power dissipation maps were developed for identification of exact instability regions and optimization of hot processing parameters. The experimental results indicated that the efficiency factor of energy dissipate (η) lowered to the minimum value when the deformation conditions located at the strain of 0.4, temperature of 300 ° C and strain rate of 1 s-1. The softening mechanism was dynamic recovery, the grain shape was mainly flat, and the portion of high angle grain boundary (〉15°) was 34%. While increasing the deformation temperature to 400 ° C and decreasing the strain rate to 0.1 s-1, a maximum value of η was obtained. It can be found that the main softening mechanism was dynamic recrystallization, the structures were completely recrystallized, and the portion of high angle grain boundary accounted for 86.5%. According to 2D processing maps and 3D power dissipation maps, the optimum processing conditions for the extrusion preform of the spray-formed Al?9.0Mg?0.5Mn?0.1Ti alloy were in the deformation temperature range of 340-450 ° C and the strain rate range of 0.01-0.1 s-1 with the power dissipation efficiency range of 38%?43%. 展开更多
关键词 spray forming Al-9.0Mg-0.5Mn-0.1Ti alloy hot compressing deformation processing map dynamic recrystallization
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