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Hot Compression Deformation Behavior and Processing Maps of Mg-Zn-Mn(-Sn)-Ca Alloy 认领 引用
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作者 Chen Xia Zhu Yulong +2 位作者 Liu Quanyi Zhang Dingfei Pan Fusheng 《稀有金属材料与工程》 SCIE EI CAS CSCD 北大核心 2026年第3期627-635,共9页
The hot compression deformation behavior of Mg-6Zn-1Mn-0.5Ca(ZM61-0.5Ca)and Mg-6Zn-1Mn-2Sn-0.5Ca(ZMT612-0.5Ca)alloys was investigated at deformation temperatures ranging from 250℃to 400℃and strain rates varying from... The hot compression deformation behavior of Mg-6Zn-1Mn-0.5Ca(ZM61-0.5Ca)and Mg-6Zn-1Mn-2Sn-0.5Ca(ZMT612-0.5Ca)alloys was investigated at deformation temperatures ranging from 250℃to 400℃and strain rates varying from 0.001 s-1 to 1 s-1.The results show that the addition of Sn promotes dynamic recrystallization(DRX),and CaMgSn phases can act as nucleation sites during the compression deformation.Flow stress increases with increasing the strain rate and decreasing the temperature.Both the ZM61-0.5Ca and ZMT612-0.5Ca alloys exhibit obvious DRX characteristics.CaMgSn phases can effectively inhibit dislocation motion with the addition of Sn,thus increasing the peak fl ow stress of the alloy.The addition of Sn increases the hot deformation activation energy of the ZM61-0.5Ca alloy from 199.654 kJ/mol to 276.649 kJ/mol,thus improving the thermal stability of the alloy.For the ZMT612-0.5Ca alloy,the optimal hot deformation parameters are determined to be a deformation temperature range of 350–400℃and a strain rate range of 0.001–0.01 s-1. 展开更多
关键词 hot deformation constitutive equation processing map deformation activation energy magnesium alloy
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Hot deformation behaviors and processing maps of Mg-Zn-Er alloys based on Gleeble-1500 hot compression simulation 认领 引用 被引量：17
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作者 Cui-cui SUN Ke LIU +3 位作者 Zhao-hui WANG Shu-bo LI Xian DU Wen-bo DU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第12期3123-3134,共12页
The hot deformation behaviors of as-solution Mg?xZn?yEr alloys (x/y=6, x=3.0, 4.5 and 6.0; y=0.50, 0.75 and 1.00) wereinvestigated on Gleeble?1500 thermal simulator in a temperature range of 200?450 °C at a strai... The hot deformation behaviors of as-solution Mg?xZn?yEr alloys (x/y=6, x=3.0, 4.5 and 6.0; y=0.50, 0.75 and 1.00) wereinvestigated on Gleeble?1500 thermal simulator in a temperature range of 200?450 °C at a strain rate of 0.001?1 s?1. The truestress?strain curves showed the dynamic competition between the working hardening and working softening mainly due to thedynamic recrystallization (DRX) occurring during hot compression. The constitutive equations were constructed which couldaccurately predict the peak stress of the alloys. The addition of Zn and/or Er resulted in higher deformation activation energy forMg?3Zn?0.5Er (alloy A). The processing maps were constructed as function of the temperature and the strain rate, providing theoptimum hot working conditions (i.e., at strain of 0.3, Mg?3Zn?0.5Er (alloy A): 380?430 ?C, <0.1 s?1; Mg?4.5Zn?0.75Er (alloy B):380?450 ?C, 0.01?0.1 s?1; Mg?6Zn?1Er (alloy C): 390?440 ?C, 0.01?0.1 s?1). The as-solution treated Mg?4.5Zn?0.75Er (alloy B)demonstrated more optimum hot working window comparing with Mg?3Zn?0.5Er (alloy A) and Mg?6Zn?1Er (alloy C). 展开更多
关键词 Mg-Zn-Er alloy compression behavior microstructure evolution constitutive equations processing map
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Effect of Al3Zr particles on hot-compression behavior and processing map for Al-Cu-Li based alloys at elevated temperatures 认领 引用 被引量：10
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作者 Qing-bo YANG Yan-jun DENG +3 位作者 Mou YANG Zhi-qing ZHANG Wei-guo LI Qing LIU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第4期872-882,共11页
The influence of Al3Zr particles on the hot compression behavior and processing map(PM)of Al-Cu-Li based alloys under isothermal plane-strain compression in the temperature range of 400-500℃and at the strain rates of... The influence of Al3Zr particles on the hot compression behavior and processing map(PM)of Al-Cu-Li based alloys under isothermal plane-strain compression in the temperature range of 400-500℃and at the strain rates of 0.01-10 s^-1 was investigated.The corresponding microstructure was analyzed using optical microscopy(OM),electron back-scattered diffraction(EBSD)and transmission electron microscope(TEM).The results showed that dynamic recovery(DRV)played a greater role than dynamic recrystallization(DRX)in dynamic softening.At low temperatures,the Al3Zr particles were the significant barriers to inhibit DRV and DRX grain growth.When the temperature reached 500℃,the Al3Zr particles readily spread along grain boundaries just like a necklace due to the dissolution of Al3Zr particles and rapid diffusion of Zr through grain boundary,resulting in generating the macroscopic cracks and forming an instability domain at 490-500℃,0.01 s^-1 in the PM. 展开更多
关键词 Al-Cu-Li based alloy Al3Zr particle hot compression processing map
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Hot compression behavior and processing map of cast Mg-4Al-2Sn-Y-Nd alloy 认领 引用 被引量：12
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作者 王晶 史宝良 杨院生 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第3期626-631,共6页
The plastic flow behavior of a newly developed high ductility magnesium alloy, Mg-4Al-2Sn-Y-Nd, was investigated by hot compression from 200 to 400 ℃ with a strain rate of 1.5×10-3 to 7.5 s-1. The results reveal... The plastic flow behavior of a newly developed high ductility magnesium alloy, Mg-4Al-2Sn-Y-Nd, was investigated by hot compression from 200 to 400 ℃ with a strain rate of 1.5×10-3 to 7.5 s-1. The results reveal that the strain rate sensitivity factor （m） of the alloy is much lower than that of the AZ31 alloy, which implies that the alloy should be more suitable for processing at high strain rate. The constitutive relationship of the alloy deformed at elevated temperature was obtained by plotting the experimental data. The stress exponent of the alloy is 10.33, which reveals that climb-controlled dislocations creep is the dominated deformation mechanism. The processing-map technique was used to determine the practical processing window. The proper deformation temperature and strain rate of the cast alloy were determined as 350-400 ℃ and 0.01-0.03 s-1, respectively. 展开更多
关键词 magnesium alloy uniaxial compression apparent activation energy processing map
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Using structure restoration maps to comprehensively identify potential faults and fractures in compressional structures 认领 引用 被引量：6
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作者 欧成华 陈伟 李朝纯 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第3期677-684,共8页
Faults and fractures of multiple scales are frequently induced and generated in compressional structural system. Comprehensive identification of these potential faults and fractures that cannot be distinguished direct... Faults and fractures of multiple scales are frequently induced and generated in compressional structural system. Comprehensive identification of these potential faults and fractures that cannot be distinguished directly from seismic profile of the complex structures is still an unanswered problem. Based on the compressional structural geometry and kinematics theories as well as the structural interpretation from seismic data, a set of techniques is established for the identification of potential faults and fractures in compressional structures. Firstly, three-dimensional(3D) patterns and characteristics of the faults directly interpreted from seismic profile were illustrated by 3D structural model. Then, the unfolding index maps, the principal structural curvature maps, and tectonic stress field maps were obtained from structural restoration. Moreover, potential faults and fractures in compressional structures were quantitatively identified relying on comprehensive analysis of these three maps. Successful identification of the potential faults and fractures in Mishrif limestone formation and in Asmari dolomite formation of Buzurgan anticline in Iraq demonstrates the applicability and reliability of these techniques. 展开更多
关键词 potential fault and fracture comprehensive identification structure restoration maps 3D structural modeling compressional structures
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Flow stress behavior and processing map of extruded 7075Al/SiC particle reinforced composite prepared by spray deposition during hot compression 认领 引用 被引量：6
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作者 吴红丹 张辉 +1 位作者 陈爽 傅定发 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第3期692-698,共7页
Hot compression tests of the extruded 7075Al/15%SiC (volume fraction) particle reinforced composite prepared by spray deposition were performed on Gleeble?1500 system in the temperature range of 300?450 °C and st... Hot compression tests of the extruded 7075Al/15%SiC (volume fraction) particle reinforced composite prepared by spray deposition were performed on Gleeble?1500 system in the temperature range of 300?450 °C and strain rate range of 0.001?1 s?1. The results indicate that the true stress?true strain curve almost exhibits rapid flow softening phenomenon without an obvious work hardening, and the stress decreases with increasing temperature and decreasing strain rate. Moreover, the stress levels are higher at temperature below 400 °C but lower at 450 °C compared with the spray deposited 7075Al alloy. Superplastic deformation characteristics are found at temperature of 450 °C and strain rate range of 0.001?0.1 s?1 with corresponding strain rate sensitivity of 0.72. The optimum parameters of hot working are determined to be temperature of 430?450 °C and strain rate of 0.001?0.05 s?1 based on processing map and optical microstructural observation. 展开更多
关键词 7075 Al SiC particle-reinforced composite hot compression deformation flow stress processing map superplastic deformation
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Deformation behavior and processing maps during isothermal compression of TC21 alloy 认领 引用 被引量：6
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作者 Jun Gao Miao-Quan Li +1 位作者 Ge-Jun Liu Shao-Fei Liu 《Rare Metals》 SCIE EI CAS CSCD 2017年第2期86-94,共9页
In this study,isothermal compression tests were conducted at a Gleeble-1500 simulator at deformation temperatures ranging from 1073 to 1283 K,strain rates ranging from 0.01 to 5.00 s^（-1）,and height reductions rangi... In this study,isothermal compression tests were conducted at a Gleeble-1500 simulator at deformation temperatures ranging from 1073 to 1283 K,strain rates ranging from 0.01 to 5.00 s^（-1）,and height reductions ranging from 20%to 60%.The flow stress and apparent activation energy for deformation and constitutive equation were used to characterize the deformation behavior of TC21 alloy during the isothermal compression.The processing maps combined microstructure observations were established based on dynamic material model（DMM） over a range of strain rates and temperatures.The results show that an initial yield drop is observed above 1203 K or at higher strain rates ranging from 1.00 to 5.00 s^-1,and oscillatory flow curves are presented particularly at a strain rate of 5.00 s^-1.Strain has some influence on the apparent activation energy for deformation during the isothermal compression of TC21 alloy.The Q-values and microstructure observation confirm that dynamic recrystallization（DRX） occurs in the β single-phase region.The constitutive equation during the isothermal compression of TC21 alloy is developed using the Zener-Hollomon parameter in the exponent-type equation.The maximum and minimum relative errors between the calculated and the experimental flow stress are 14.1%and 0.3%,respectively.The peak efficiency of power dissipation at a strain of 0.7 is about 0.51 occurring at a deformation temperature of 1073 K and strain rate of 0.01 s^-1,corresponding to an optimal deformation condition of TC21 alloy. 展开更多
关键词 TC21 alloy Flow stress Apparent activation energy for deformation Constitutive equation Processing Maps
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Effect of Cr elimination on flow behavior and processing map of newly developed ECO-7175 aluminum alloy during hot compression 认领 引用 被引量：4
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作者 Majid SEYED-SALEHI Bong Hwan KIM +2 位作者 Seung Yoon YANG Shae Kwang KIM Ghasem EISAABADI BOZCHALOEI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第5期1442-1459,共18页
ECO-Al alloys are introduced as a game-changer for the aluminum industry and it is of utmost importance to determine the role of alloying elements in their processing characteristics.In this study,the effects of Cr on... ECO-Al alloys are introduced as a game-changer for the aluminum industry and it is of utmost importance to determine the role of alloying elements in their processing characteristics.In this study,the effects of Cr on the hot deformation behavior of newly-developed ECO-7175 alloy were investigated.ECO-7175 samples with and without Cr were hot-compressed using a Gleeble simulator(temperature range of 350−500℃ and strain rates of 0.001−1 s−1).The results were used to study the constitutive equations,the processing maps,and the microstructural evolution of the alloys.In Cr-containing alloy,the analysis of the deformation activation energy reveals that the rate-controlling mechanisms of the deformation change gradually from self-diffusion of Al(or diffusion of Mg in Al)to diffusion of Cr in Al by decreasing the Zener−Hollomon parameter.The analysis of the processing maps of Cr-containing alloy shows that the dynamic recrystallization(DRX)zone is limited to the deformation at high temperatures and low strain rates and expands with increasing applied strain.On the other hand,it is found that the self-diffusion of Al(or Mg in Al)is the only rate-controlling mechanism during hot deformation of Cr-free alloy in all processing conditions and its DRX zone is independent of the plastic strain. 展开更多
关键词 hot deformation constitutive equation processing map ECO-7175 aluminum alloy
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Hybrid Image Compression-Encryption Scheme Based on Multilayer Stacked Autoencoder and Logistic Map 认领 引用 被引量：1
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作者 Neetu Gupta Ritu Vijay 《China Communications》 SCIE CSCD 2022年第1期238-252,共15页
Secure transmission of images over a communication channel, with limited data transfer capacity, possesses compression and encryption schemes. A deep learning based hybrid image compression-encryption scheme is propos... Secure transmission of images over a communication channel, with limited data transfer capacity, possesses compression and encryption schemes. A deep learning based hybrid image compression-encryption scheme is proposed by combining stacked auto-encoder with the logistic map. The proposed structure of stacked autoencoder has seven multiple layers, and back propagation algorithm is intended to extend vector portrayal of information into lower vector space. The randomly generated key is used to set initial conditions and control parameters of logistic map. Subsequently, compressed image is encrypted by substituting and scrambling of pixel sequences using key stream sequences generated from logistic map.The proposed algorithms are experimentally tested over five standard grayscale images. Compression and encryption efficiency of proposed algorithms are evaluated and analyzed based on peak signal to noise ratio(PSNR), mean square error(MSE), structural similarity index metrics(SSIM) and statistical,differential, entropy analysis respectively. Simulation results show that proposed algorithms provide high quality reconstructed images with excellent levels of security during transmission.. 展开更多
关键词 compression-encryption stacked autoencoder chaotic system back propagation algorithm logistic map
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Flow Stress Behavior and Processing Map of Al-Cu-Mg-Ag Alloy during Hot Compression 认领 引用 被引量：4
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作者 YANG Sheng YI Danqing +1 位作者 ZHANG Hong YAO Sujuan 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2008年第5期694-698,共5页
The hot deformation behavior of Al-Cu-Mg-Ag was studied by isothermal hot compression tests in the temperature range of 573-773 K and strain rate range of 0.001-1 s^-1 on a Gleeble 1500 D thermal mechanical simulator.... The hot deformation behavior of Al-Cu-Mg-Ag was studied by isothermal hot compression tests in the temperature range of 573-773 K and strain rate range of 0.001-1 s^-1 on a Gleeble 1500 D thermal mechanical simulator.The results show the flow stress of Al-Cu-Mg-Ag alloy increases with strain rate and decreases after a peak value,indicating dynamic recovery and recrystallization.A hyperbolic sine relationship is found to correlate well the flow stress with the strain rate and temperature,the flow stress equation is estimated to illustrate the relation of strain rate and stress and temperature during high temperature deformation process.The processing maps exhibit two domains as optimum fields for hot deformation at different strains,including the high strain rate domain in 623-773 K and the low strain rate domain in 573-673 K. 展开更多
关键词 Al-Cu-Mg-Ag alloy flow stress behavior constitutive equation processing map
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Constructive Texture Steganography Based on Compression Mapping of Secret Messages 认领 引用
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作者 Fengyong Li Zongliang Yu Chuan Qin 《Computer Modeling in Engineering & Sciences》 SCIE EI 2020年第7期393-410,共18页
This paper proposes a new constructive texture synthesis steganographic scheme by compressing original secret messages.First,we divide the original message into multiple bit blocks,which are transferred to decimal val... This paper proposes a new constructive texture synthesis steganographic scheme by compressing original secret messages.First,we divide the original message into multiple bit blocks,which are transferred to decimal values and compressed into small decimal values by recording their interval sign characters.Then,a candidate pattern is generated by combining the given source pattern and boundary extension algorithm.Furthermore,we segment the candidate pattern into multiple candidate patches and use affine transformation algorithm to locate secret positions on a blank canvas,which are used to hide the sign characters by mapping the candidate patches.Finally,we select the candidate patches with minimal mean square error to represent secret bits to generate stego image by image quilting.Extensive experiments demonstrate that compared with existing texture steganographic methods,our method has a better visual quality,higher embedding capacity and security performance,while maintaining strong anti-steganalysis capability. 展开更多
关键词 Constructive steganography texture synthesis compression mapping patch
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Efficient Compression of Vector Data Map Based on a Clustering Model 认领 引用 被引量：5
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作者 YANG Bisheng LI Qingquan 《Geo-Spatial Information Science》 EI 2009年第1期13-17,共5页
This paper proposes a new method for the compression of vector data map.Three key steps are encompassed in the proposed method,namely,the simplification of vector data map via the elimination of vertices,the compressi... This paper proposes a new method for the compression of vector data map.Three key steps are encompassed in the proposed method,namely,the simplification of vector data map via the elimination of vertices,the compression of re-moved vertices based on a clustering model,and the decoding of the compressed vector data map.The proposed compres-sion method was implemented and applied to compress vector data map to investigate its performance in terms of the com-pression ratio and distortions of geometric shapes.The results show that the proposed method provides a feasible and effi-cient solution for the compression of vector data map and is able to achieve a promising ratio of compression and maintain the main shape characteristics of the spatial objects within the compressed vector data map. 展开更多
关键词 spatial data decoding spatial data compression error evaluation
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Processing map and hot working mechanisms of Cu-Ag alloy in hot compression process 认领 引用 被引量：9
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作者 王梦寒 黄龙 +1 位作者 陈明亮 王彦丽 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第3期821-828,共8页
For Gu-Ag alloy, an important parameter called workability in the forming process of materials can be evaluated by processing maps yielded from the stress-strain data generated by hot compression tests at temperatures... For Gu-Ag alloy, an important parameter called workability in the forming process of materials can be evaluated by processing maps yielded from the stress-strain data generated by hot compression tests at temperatures of 700-850 °C and strain rates of 0.01-10 s-1. And at the true strain of 0.15, 0.35 and 0.55, respectively, the responses of strain-rate sensitivity, power dissipation efficiency and instability parameter to temperature and strain rate were studied. Instability maps and power dissipation maps were superimposed to form processing maps, which reveal the determinate regions where individual metallurgical processes occur and the limiting conditions of flow instability regions. Furthermore, the optimal processing parameters for bulk metal working are identified clearly by the processing maps. 展开更多
关键词 Cu-Ag alloy strain-rate sensitivity hot working mechanism processing map
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Fractal Image Compression Using Self-Organizing Mapping 认领 引用 被引量：1
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作者 Rashad A. Al-Jawfi Baligh M. Al-Helali Adil M. Ahmed 《Applied Mathematics》 2014年第12期1810-1819,共10页
One of the main disadvantages of fractal image data compression is a loss time in the process of image compression (encoding) and conversion into a system of iterated functions (IFS). In this paper, the idea of the in... One of the main disadvantages of fractal image data compression is a loss time in the process of image compression (encoding) and conversion into a system of iterated functions (IFS). In this paper, the idea of the inverse problem of fixed point is introduced. This inverse problem is based on collage theorem which is the cornerstone of the mathematical idea of fractal image compression. Then this idea is applied by iterated function system, iterative system functions and grayscale iterated function system down to general transformation. Mathematical formulation form is also provided on the digital image space, which deals with the computer. Next, this process has been revised to reduce the time required for image compression by excluding some parts of the image that have a specific milestone. The neural network algorithms have been applied on the process of compression (encryption). The experimental results are presented and the performance of the proposed algorithm is discussed. Finally, the comparison between filtered ranges method and self-organizing method is introduced. 展开更多
关键词 Fractal Image Compression Organizing Mapping
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Full-field mapping of internal strain distribution in red sandstone specimen under compression using digital volumetric speckle photography and X-ray computed tomography 认领 引用 被引量：7
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作者 Lingtao Mao Jianping Zuo +1 位作者 Zexun Yuan Fu-Pen Chiang 《Journal of Rock Mechanics and Geotechnical Engineering》 CSCD 2015年第2期136-146,共11页
It is always desirable to know the interior deformation pattern when a rock is subjected to mechanicalload. Few experimental techniques exist that can represent full-field three-dimensional （3D） straindistribution i... It is always desirable to know the interior deformation pattern when a rock is subjected to mechanicalload. Few experimental techniques exist that can represent full-field three-dimensional （3D） straindistribution inside a rock specimen. And yet it is crucial that this information is available for fully understandingthe failure mechanism of rocks or other geomaterials. In this study, by using the newlydeveloped digital volumetric speckle photography （DVSP） technique in conjunction with X-ray computedtomography （CT） and taking advantage of natural 3D speckles formed inside the rock due to materialimpurities and voids, we can probe the interior of a rock to map its deformation pattern under load andshed light on its failure mechanism. We apply this technique to the analysis of a red sandstone specimenunder increasing uniaxial compressive load applied incrementally. The full-field 3D displacement fieldsare obtained in the specimen as a function of the load, from which both the volumetric and the deviatoricstrain fields are calculated. Strain localization zones which lead to the eventual failure of the rock areidentified. The results indicate that both shear and tension are contributing factors to the failuremechanism. 2015 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved. 展开更多
关键词 Red sandstone Strain localization Uniaxial compression Digital volumetric speckle photography(DVSP) X-ray micro-tomography
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Constitutive behavior, microstructural evolution and processing map of extruded Al-1.1Mn-0.3Mg-0.25RE alloy during hot compression 认领 引用 被引量：9
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作者 张添 陶友瑞 王学印 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第5期1337-1345,共9页
Hot compression tests of an extruded Al-1.1Mn-0.3Mg-0.25RE alloy were performed on Gleeble-1500 system in the temperature range of 300-500 ℃ and strain rate range of 0.01-10 s-l. The associated microstructural evolut... Hot compression tests of an extruded Al-1.1Mn-0.3Mg-0.25RE alloy were performed on Gleeble-1500 system in the temperature range of 300-500 ℃ and strain rate range of 0.01-10 s-l. The associated microstructural evolutions were studied by observation of optical and transmission electron microscopes. The results show that the peak stress level decreases with increasing deformation temperature and decreasing strain rate, which can be represented by a Zener-Hollomon parameter in the hyperbolic-sine equation with the hot deformation activation energy of 186.48 kJ/mol. The steady flow behavior results from dynamic recovery whereas flow softening is associated with dynamic recrystallization and dynamic transformation of constituent particles. The main constituent particles are enriched rare earth phases. Positive purifying effects on impurity elements of Fe and Si are shown in the Al-l.lMn-0.3Mg-0.25RE alloy, which increases the workability at high temperature. Processing map was calculated and an optimum processing was determined with deformation temperature of 440-450 ℃ and strain rate of 0.01 s-1. 展开更多
关键词 Al-1.1Mn-0.3Mg-0.25RE alloy flow stress constitutive behavior microstructural characterization processing map
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T1 mapping和T2 mapping技术在妇科恶性肿瘤中的研究进展 认领 引用
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作者 张旭霞 邓林 +6 位作者 翟晓静 孙碧霞 曹珊 钱吉芳 张士朋 梁莉 朱大林 《磁共振成像》 CAS CSCD 北大核心 2026年第3期206-212,共7页
近年来,妇科恶性肿瘤的发病率逐渐上升且呈现年轻化的趋势,磁共振成像(magnetic resonance imaging,MRI)因具有较高的软组织分辨力及多序列、多方位成像等优点,在妇科肿瘤的诊断、分期及预后评估中广泛应用,但常规序列却无法精准捕捉肿... 近年来,妇科恶性肿瘤的发病率逐渐上升且呈现年轻化的趋势,磁共振成像(magnetic resonance imaging,MRI)因具有较高的软组织分辨力及多序列、多方位成像等优点,在妇科肿瘤的诊断、分期及预后评估中广泛应用,但常规序列却无法精准捕捉肿瘤组织早期的病理生理变化。T1 mapping与T2 mapping技术作为MR功能成像领域的核心技术组合,其各自的核心定量参数T1值与T2值分别从组织纵向弛豫特性和横向弛豫特性角度,精准反映病变组织内水分子分布、蛋白质结合状态及组织灌注等微观病理生理改变,是解析肿瘤病变性质、评估疾病进展及监测治疗响应的重要影像指标。本综述将系统梳理T1 mapping与T2 mapping技术的最新研究进展,系统分析其在宫颈癌、子宫内膜癌、卵巢癌等常见妇科恶性肿瘤的诊断鉴别、分期分级、疗效监测及预后评估中的应用价值,同时探讨当前研究中存在的扫描时间、标准化程度、伪影干扰等局限性,进而提出未来的优化方向。以期更全面地揭示妇科恶性肿瘤的病理生理机制,为该领域的精准诊疗研究提供新的思路与方向。 展开更多
关键词 宫颈癌 子宫内膜癌 卵巢癌 磁共振成像 T1 mapping T2 mapping
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A Comprehensive Literature Review of AI-Driven Application Mapping and Scheduling Techniques for Network-on-Chip Systems 认领 引用
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作者 Naveed Ahmad Muhammad Kaleem +5 位作者 Mourad Elloumi Muhammad Azhar Mushtaq Ahlem Fatnassi Mohd Fazil Anas Bilal Abdulbasit A.Darem 《Computer Modeling in Engineering & Sciences》 SCIE EI 2026年第1期118-155,共38页
Network-on-Chip(NoC)systems are progressively deployed in connecting massively parallel megacore systems in the new computing architecture.As a result,application mapping has become an important aspect of performance ... Network-on-Chip(NoC)systems are progressively deployed in connecting massively parallel megacore systems in the new computing architecture.As a result,application mapping has become an important aspect of performance and scalability,as current trends require the distribution of computation across network nodes/points.In this paper,we survey a large number of mapping and scheduling techniques designed for NoC architectures.This time,we concentrated on 3D systems.We take a systematic literature review approach to analyze existing methods across static,dynamic,hybrid,and machine-learning-based approaches,alongside preliminary AI-based dynamic models in recent works.We classify them into several main aspects covering power-aware mapping,fault tolerance,load-balancing,and adaptive for dynamic workloads.Also,we assess the efficacy of each method against performance parameters,such as latency,throughput,response time,and error rate.Key challenges,including energy efficiency,real-time adaptability,and reinforcement learning integration,are highlighted as well.To the best of our knowledge,this is one of the recent reviews that identifies both traditional and AI-based algorithms for mapping over a modern NoC,and opens research challenges.Finally,we provide directions for future work toward improved adaptability and scalability via lightweight learned models and hierarchical mapping frameworks. 展开更多
关键词 Application mapping mapping techniques network-on-chip system on chip optimisation
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基于心肌T1/T2mapping影像组学特征在鉴别肥厚型心肌病和扩张型心肌病的应用 认领 引用
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作者 张丽红 尤茜怡 +2 位作者 郭亚楠 万正国 焦凤辉 《中国CT和MRI杂志》 2026年第7期56-60,共5页
目的评估心肌T1/T2mapping影像组学特征在鉴别肥厚型心肌病(HCM)和扩张型心肌病(DCM)的价值,为HCM与DCM的早期精准鉴别提供临床依据。方法选取2022年1月至2025年1月我院收治的82例HCM患者与82例DCM患者作为研究对象,按7:3的比例随机分... 目的评估心肌T1/T2mapping影像组学特征在鉴别肥厚型心肌病(HCM)和扩张型心肌病(DCM)的价值,为HCM与DCM的早期精准鉴别提供临床依据。方法选取2022年1月至2025年1月我院收治的82例HCM患者与82例DCM患者作为研究对象,按7:3的比例随机分为训练集(n=115)和测试集(n=49)。采用多因素Logistic回归分别构建临床模型、影像组学模型以及融合模型;通过受试者工作特征(ROC)、Hosmer-Lemeshow检验、校准曲线及决策曲线(DCA)评估三种模型的诊断效能与临床价值。结果多因素Logistic回归分析结果显示,初始T1值、强化后T1值与T2值均是心肌病类型的影响因素,以此构建临床模型:P=1.672+0.032×初始T1值+0.094×强化后T1值-0.215×T2值。经特征提取及降维筛选,最终保留9个特征参数构建影像组学模型:影像组学标签(Ra d-score)=0.120+1.253×original_shape_Sphericity-0.835×gradient_ffiifirstorder_Minimum+1.472×lbp-3D-m1_firstorder_Energy+0.927×square_firstorder_Root Mean Squared-1.156×log-sigma-2-0-mm-3D_firstorder_Median+0.784×wavelet-LHL_gldm_Dependence Variance+0.647×wavelet-HLL_glszm_Small Area Emphasis-0.513×wavelet-HLH_ngtdm_Busyness+1.088×original_g l r l m_Lo n g R u n E m p h a s i s。构建融合模型为:P=4.306+1.296×初始T1值-0.320×T2值+1.675×Rad-score。训练集与测试集的融合模型曲线下面积(AUC)分别为0.931、0.925,均高于单纯临床模型与影像组学模型,校准度与临床净收益亦表现最优。结论基于心肌T1/T2 mapping的影像组学特征能有效鉴别HCM与DCM,其与心肌T1/T2定量指标构建的融合模型具有更高的诊断效能和临床实用性,可作为临床鉴别HCM与DCM的有效工具。 展开更多
关键词 T1 Mapping T2 Mapping 影像组学 心脏磁共振 肥厚型心肌病 扩张型心肌病
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Robust and efficient visual odometry using colored point cloud maps via dual-sparsity and hierarchical optimization 认领 引用
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作者 Xuanxuan Zhang You Li +4 位作者 Tianxiang Zhang Zhenqi Zheng Xueli Guo Zhichao Wen Fuqiang Gu 《Satellite Navigation》 SCIE EI CSCD 2026年第1期224-245,I0005,共22页
Reliable localization is fundamental to navigation in GNSS-challenged environments,yet monocular visual odometry(VO)inevitably suffers from drift without global constraints.Point cloud maps can provide global correcti... Reliable localization is fundamental to navigation in GNSS-challenged environments,yet monocular visual odometry(VO)inevitably suffers from drift without global constraints.Point cloud maps can provide global corrections to mitigate this drift.However,existing heterogeneous feature registration methods fail to fully exploit the shared information between vision and point clouds.This limitation results in suboptimal localization accuracy,reduced robustness,and increased computational overhead.To address these issues,we propose a visual odometry system based on colored point cloud maps,which leverages both the global point cloud map as a constraint and the shared modality(color)between the colored point cloud map and the camera to ensure localization accuracy and robustness.The system consists of two main components:sparse colored point cloud construction and visual localization.In the sparse colored point cloud construction module,we introduce a map sparsification strategy that associates visual gradients with point clouds,ensuring that the retained sparse point cloud preserves salient visual gradient information,thereby reducing computational costs.This strategy is further incorporated into the vision-to-map matching stage,forming a“dual-sparsity matching”scheme.In the localization stage,we propose a hierarchical optimization-based iterative Kalman filtering algorithm,which performs multi-level iterative optimization over multi-resolution images to prevent localization from getting trapped in local optima while enhancing accuracy.Experiments on public and self-collected sequences demonstrate significant gains in both accuracy and efficiency.Compared with a representative map-based method(DSL),the proposed approach reduces ATE(RMSE)by 52%–95%across multiple challenging sequences,with a representative improvement from 1.883 to 0.152 m on R3live_5(91.92%reduction).Against the learning-based I2D-Loc++,our method achieves accuracy gains of up to 76.6%and maintains robust tracking in extreme cases(e.g.,R3live_3/4)where I2D-Loc++and ORB-SLAM3 fail due to visual degradation.Furthermore,the system maintains near real-time efficiency,reducing total processing time by up to 47.7%(e.g.,from 121.11 to 63.34 s on Whu_1).Even under severe geometric degeneracy,our tracker remains robust with an ATE of 0.076 m,whereas geometry-only LiDAR–IMU localization degrades to 9.23 m. 展开更多
关键词 Map-based localization Visual odometry Colored point cloud map Dual-sparsity Hierarchical optimization
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