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An improved initial rotor position estimation method using high-frequency pulsating voltage injection for PMSM

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Defence Technology（防务技术） 2024年第3期33卷 19-29页

作者： Yang Jiang ming Cheng School of Electrical Engineering Southeast UniversityNanjing 210096China

High frequency pulsating voltage injection method is a good candidate for detecting the initial rotor position of permanent magnet synchronous ***,traditional methods require a large number of filters,which leads to the deterioration of system stability and dynamic *** order to solve these problems,a new signal demodulation method is proposed in this *** proposed new method can directly obtain the amplitude of high-frequency current,thus eliminating the use of filters,improving system stability and dynamic performance and saving the work of adjusting filter *** addition,a new magnetic polarity detection method is proposed,which is robust to current measurement ***,experiments verify the effectiveness of the method.

关键词： Initial position detection Signal demodulation algorithm Magnetic polarity detection Filter elimination

Geometry and formation mechanism of tension gashes and their implication on the hydrocarbon accumulation in the deep-seated strata of sedimentary basin:A case from Shunnan area of Tarim Basin

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Petroleum Science 2024年第1期21卷 87-99页

作者： Yan-Nan Du Kong-you Wu Yin Liu Yan-Ying Li Zi-Cheng Cao you-Wei Cui Jun Liu Key Laboratory of Deep Oil and Gas School of GeosciencesChina University of Petroleum(East China)Qingdao 266580ShandongChina Exploration and Development Research Institute SINOPEC Northwest Oilfield BranchUrumqi 830011XinjiangChina The Fifth Gas Production Plant Changqing OilfieldPetroChinaXi'an 710018ShaanxiChina

With the theoretical and technological developments related to cratonic strike-slip faults,the Shuntuoguole Low Uplift in the Tarim Basin has attracted considerable attention *** by multi-stage tectonic movements,the strike-slip faults have controlled the distribution of hydrocarbon resources owing to the special fault characteristics and fault-related *** contrast,the kinematics and formation mechanism of strike-slip faults in buried sedimentary basins are difficult to investigate,limiting the discussion of these faults and hydrocarbon *** this study,we identified the characteristics of massive sigmoidal tension gashes(STGs)that formed in the Shunnan area of the Tarim ***-resolution three-dimensional seismic data and attribute analyses were used to investigate their geometric and kinematic ***,the stress state of each point of the STGs was calculated using seismic curvature ***,the formation mechanism of the STGs and their roles in controlling hydrocarbon migration and accumulation were *** results suggest that:(1.the STGs developed in the Shunnan area have a wide distribution,with a tensile fault arranged in an enéchelon pattern,showing an S-shaped *** STGs formed in multiple stages,and differential rotation occurred along the direction of strike-slip stress during formation.(2)Near the principal displacement zone of the strike-slip faults,the stress value of the STGs was higher,gradually decreasing at both *** shallow layer deformation was greater than the deep layer deformation.(3)STGs are critical for connecting source rocks,migrating oil and gas,sealing horizontally,and developing efficient *** study not only provides seismic evidence for the formation and evolution of super large STGs,but also provides certain guidance for oil and gas exploration in this area.

关键词： Tarim Basin Sigmoidal tension gashes Seismic attributes Shear stress calculation Formation mechanism Reservoir control

A Deep Learning Method for Computing Eigenvalues of the Fractional Schrödinger Operator

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Journal of Systems Science & Complexity 2024年第2期37卷 391-412页

作者： GUO Yixiao ming Pingbing LSEC Institute of Computational Mathematics and Scientific/Engineering ComputingAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

The authors present a novel deep learning method for computing eigenvalues of the fractional Schrödinger *** proposed approach combines a newly developed loss function with an innovative neural network architecture that incorporates prior knowledge of the *** improvements enable the proposed method to handle both high-dimensional problems and problems posed on irregular bounded *** authors successfully compute up to the first 30 eigenvalues for various fractional Schrödinger *** an application,the authors share a conjecture to the fractional order isospectral problem that has not yet been studied.

关键词： Eigenvalue problem deep learning fractional Schrödinger operator isospectral problem

Dual Frequency Transformer for Efficient SDR-to-HDR Translation

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Machine Intelligence Research 2024年第3期21卷 538-548页

作者： Gang Xu Qibin Hou ming-ming Cheng Tianjin Media Computing Center College of Computer ScienceNankai UniversityTianjin300000China

The SDR-to-HDR translation technique can convert the abundant standard-dynamic-range (SDR) media resources to high-dynamic-range (HDR) ones, which can represent high-contrast scenes, providing more realistic visual experiences. While recent vision Transformers have achieved promising performance in many low-level vision tasks, there are few works attempting to leverage Transformers for SDR-to-HDR translation. In this paper, we are among the first to investigate the performance of Transformers for SDR-to-HDR translation. We find that directly using the self-attention mechanism may involve artifacts in the results due to the inappropriate way to model long-range dependencies between the low-frequency and high-frequency components. Taking this into account, we advance the self-attention mechanism and present a dual frequency attention (DFA), which leverages the self-attention mechanism to separately encode the low-frequency structural information and high-frequency detail information. Based on the proposed DFA, we further design a multi-scale feature fusion network, named dual frequency Transformer (DFT), for efficient SDR-to-HDR translation. Extensive experiments on the HDRTV1. dataset demonstrate that our DFT can achieve better quantitative and qualitative performance than the recent state-of-the-art methods. The code of our DFT is made publicly available at https://***/CS-GangXu/DFT.

关键词： Standard-dynamic-range to high-dynamic-range(SDR-to-HDR)translation Transformer dual frequency attention(DFA) frequency-aware feature decomposition efficient model

Chiral thermally activated delayed fluorescence materials for circularly polarized organic light-emitting diodes

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Science China Chemistry 2024年第4期67卷 1097-1116页

作者： Li Yuan Yi-Pin Zhang you-Xuan Zheng State Key Laboratory of Coordination Chemistry Collaborative Innovation Center of Advanced MicrostructuresJiangsu Key Laboratory of Advanced Organic MaterialsSchool of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China

Chirality is an important natural characteristic of organic molecules,and chiral organic molecules have shown extensive application in areas such as pharmaceutical development and material *** from the ability to achieve circularly polarized luminescence(CPL),chiral luminescent materials have shown potential applications in anti-glare display,optical communication and,3D display,*** to the ability to harvest both singlet and triplet excitons by a fast reverse intersystem crossing process without involving noble metals,chiral thermally activated delayed fluorescence(TADF)materials with point chirality,axial chirality,planar chirality and helical chirality are regarded as the state-of-the-art materials for circularly polarized organic light-emitting diodes(CP-OLEDs).In recent years,the chiral TADF materials and CP-OLEDs have rapidly developed,but unfortunately,the dissymmetry factors(g)are far from the requirement of practical *** ideal emitters and devices should have both high efficiency and a g factor,or at least a balance between these two *** review gives an overview of recent progress in chiral TADF materials,with a particular focus on the chiral skeleton,CPL property and device ***,the molecular design concept,device structure and methods to improve the g factors of chiral materials and CP-OLEDs are also discussed.

关键词： chiral thermally activated delayed fluorescence material chiral skeleton circularly polarized luminescence circularly polarized organic light-emitting diodes dissymmetry factor

The δ^(1.)N values of foxtail millet(Setaria italica)and common millet(Panicum miliaceum)are reliable indicators of manuring practices

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Science China Earth Sciences 2024年第9期67卷 2910-2923页

作者： Jishuai YANG Xiaoyan YANG Ting you Fahu CHEN Key Scientific Research Base of Bioarchaeology in Cold and Arid Regions(National Cultural Heritage Administration) Key Laboratory of Western China’s Environmental Systems(Ministry of Education)College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China Group of Alpine Paleoecology and Human Adaptation(ALPHA) State Key Laboratory of Tibetan Plateau Earth SystemResources and Environment(TPESRE)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems College of Pastoral Agriculture Science and TechnologyLanzhou UniversityLanzhou 730000China

Millet agriculture,which originated in northern China,alongside rice agriculture,have nurtured the Chinese *** manuring practices likely promoted and maintained sustainable millet agricultural production in the loess area of northern ***,ongoing controversy exists regarding the indicators of prehistoric manuring intensity of foxtail millet(Setaria italica)and common millet(Panicum miliaceum).Here,we present the results of pot and field fertilization experiments on two millet *** findings suggest that manuring can significantly increase the δ^(1.)N values of foxtail millet,and its δ^(1.)N values increase with increasing manuring *** δ^(1.)N values of foxtail millet leaves are systematically greater than those of grains by approximately 1.6‰.Manuring could have a long-term residual impact on increasing the δ^(1.)N values of soil and millet *** with previous crop fertilization experiment results,we propose that the impact of manuring on the δ^(1.)N values of non-nitrogen-fixing crops is roughly *** δ^(1.)N value and amount of manure are key factors determining the extent of change in plant δ^(1.)N *** millet grain δ^(1.)N values can serve as reliable indicators of manuring ***,we provide an interpretive framework for assessing the correlation between manuring levels and the δ^(1.)N values of archaeological millet *** δ^(1.)N values of ancient millet grains suggest widespread and intensive manuring practices in prehistoric millet agriculture in northern China,spanning from the early Yangshao period to the Longshan period.

关键词： Millet farming Manuring experiment Farming system Archaeobotany North China

Development of a new Cox model for predicting long-term survival in hepatitis cirrhosis patients underwent transjugular intrahepatic portosystemic shunts

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World Journal of Gastrointestinal Surgery 2024年第2期16卷 491-502页

作者： Yi-Fan Lv Bing Zhu ming-ming Meng Yi-Fan Wu Cheng-Bin Dong Yu Zhang Bo-Wen Liu Shao-Li you Sa Lv Yong-Ping Yang Fu-Quan Liu Liver Disease Minimally Invasive Diagnosis and Treatment Center Beijing Shijitan HospitalCapital Medical UniversityBeijing 100038China Liver Vascular Disease Diagnosis and Treatment Center The Fifth Medical Center of Chinese People's Liberation Army General HospitalBeijing 100039China

BACKGROUND Transjugular intrahepatic portosystemic shunt(TIPS)placement is a procedure that can effectively treat complications of portal hypertension,such as variceal bleeding and refractory ***,there have been no specific studies on predicting long-term survival after TIPS *** To establish a model to predict long-term survival in patients with hepatitis cirrhosis after *** A retrospective analysis was conducted on a cohort of 224 patients who un-derwent TIPS *** univariate and multivariate Cox regression analyses,various factors were examined for their ability to predict survival at 6 years after ***,a composite score was formulated,encompassing the indication,shunt reasonability,portal venous pressure gradient(PPG)after TIPS,percentage decrease in portal venous pressure(PVP),indocyanine green retention rate at 1. min(ICGR1.)and total bilirubin(Tbil)***,the performance of the newly developed Cox(NDC)model was evaluated in an in-ternal validation cohort and compared with that of a series of existing *** The indication(variceal bleeding or ascites),shunt reasonability(reasonable or unreasonable),ICGR1.,post-operative PPG,percentage of PVP decrease and Tbil were found to be independent factors affecting long-term survival after TIPS *** NDC model incorporated these parameters and successfully identified patients at high risk,exhibiting a notably elevated mortality rate following the TIPS procedure,as observed in both the training and validation ***,in terms of predicting the long-term survival rate,the performance of the NDC model was significantly better than that of the other four models[Child-Pugh,model for end-stage liver disease(MELD),MELD-sodium and the Freiburg index of post-TIPS survival].CONCLUSION The NDC model can accurately predict long-term survival after the TIPS procedure in patients with hepatitis cirrhosis,help identify high-risk patients

关键词： Transjugular intrahepatic portosystemic shunt Long-term survival Predictive model

Experimental Study of Local Scour Around Four Piles Under Different Attack Angles and Gap Ratios

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China Ocean Engineering 2024年第4期38卷 612-624页

作者： LIU ming-ming TANG Guo-qiang JIN Xin GENG Shao-yang School of Architecture and Engineering Liaocheng UniversityLiaocheng 252000China Water-Sediment Regulation and Sand Effective Utilization Special Laboratory of Shandong Provincial Education Department Liaocheng UniversityLiaocheng 252000China State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China College of Electronic Engineering Chengdu University of Information TechnologyChengdu 610225China College of Energy Chengdu University of TechnologyChengdu 610059China

In an effort to investigate and quantify the patterns of local scour,researchers embarked on an in-depth study using a systematic experimental *** research focused on the effects of local scour around a set of four piles,each subjected to different hydromechanical *** particular,this study aimed to determine how different attack angles—the angles at which the water flow impinges on the piles,and gap ratios—the ratios of the spacing between the piles to their diameters,influence the extent and nature of scour.A comprehensive series of 35 carefully designed experiments were orchestrated,each designed to dissect the nuances in how the gap ratio and attack angle might contribute to changes in the local scour observed at the base of pile *** these experimental trials,a wealth of local scour data were collected to support the *** data included precise topographic profiles of the sediment bed around the pile groups,as well as detailed scour time histories showing the evolution of scour at strategic feature points throughout the test *** analysis of the experimental data provided interesting *** study revealed that the interplay between the gap ratio and the attack angle had a pronounced influence on the scouring dynamics of the pile *** of the key observations was that the initial phases of scour,particularly within the first hour of water flow exposure,were characterized by a sharp increase in the scour depth occurring immediately in front of the *** this initial rapid development,the scour depth transitioned to a more gradual change *** contrast,the scour topography around the piles continuously *** suggests that sediment displacement and the associated sculpting of the seabed around pile foundations are sustained and progressive processes,altering the underwater landscape over *** results of this empirical investigation have significant implications for the design and constructio

关键词： local scour piles gap ratio attack angle

Association of preoperative antiviral treatment with incidences of post-hepatectomy liver failure in hepatitis B virus-related hepatocellular carcinoma

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World Journal of Gastrointestinal Surgery 2024年第7期16卷 2106-2118页

作者： Xiao Wang Zhao-Yi Lin you Zhou Qin Zhong Zong-Ren Li Xi-Xiang Lin {1.-Gen Hu Kun-Lun He Medical Big Data Research Center Chinese PLA General HospitalBeijing 100853China Medical School of Chinese PLA Chinese PLA General HospitalBeijing 100853China Department of Hepatobiliary Surgery Chinese PLA 970th HospitalYantai 264001Shandong ProvinceChina Faculty of Hepato-Pancreato-Biliary Surgery The First Medical Center of Chinese PLA General HospitalBeijing 100853China School of Medicine Nankai UniversityTianjin 300071China

BACKGROUND Post-hepatectomy liver failure(PHLF)is a common consequence of radical partial hepatectomy in hepatocellular carcinoma(HCC).AIMS To investigate the relationship between preoperative antiviral therapy and PHLF,as well as assess the potential efficacy of hepatitis B virus(HBV)DNA level in predicting *** A retrospective study was performed involving 1.01.HCC patients with HBV who underwent radical *** operating characteristic(ROC)analysis was used to assess the capacity of HBV DNA to predict PHLF and establish the optimal cutoff value for subsequent *** regression analyses were performed to assess the independent risk factors of *** increase in the area under the ROC curve,categorical net reclassification improvement(NRI),and integrated discrimination improvement(IDI)were used to quantify the efficacy of HBV DNA level for predicting *** P1.was an independent risk factor of *** the reference models by adding the variable of HBV DNA level had an improvement in area under the curve,categorical NRI,and IDI,particularly for the fibrosis-4 model,with values of 0.729(95%CI:0.705-0.754),1.382(95%CI:1.341.1.423),and 0.1.2(95%CI:0.1.0-0.1.4),*** the above findings were statistically *** In summary,preoperative antiviral treatment can reduce the incidence of PHLF,whereas an increased preoperative HBV DNA level has a correlative relationship with an increased susceptibility to PHLF.

关键词： Hepatocellular carcinoma Hepatitis B virus Preoperative antiviral treatment Liver resection Post-hepatectomy liver failure