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Quantitative reconstruction of formation paleo-pressure in sedimentary basins and case studies

Science China Earth Sciences 2020年第6期63卷 808-821页

作者： Nansheng QIU yifeng liu Wen liu Jingkun JIA State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing)Beijing 102249China College of Geosciences China University of Petroleum(Beijing)Beijing 102249China College of Ocean Zhejiang UniversityZhoushan 316021China Institute of Geomechanics Chinese Academy of Geological ScienceBeijing 100081China

Paleo-pressure reconstruction in sedimentary basins is one of the most important aspects of hydrocarbon accumulation *** view of the advantages and disadvantages of the current methods for paleo-pressure research,a new method to reconstruct the paleo-pressure is presented in this *** to the geological background,quantitative analyses of the factors that might control overpressure were first conducted to clarify the contributions of each mechanism during different geological *** evolution was reconstructed by fluid-compaction modelling with constraints imposed by the paleo-pressures obtained from fluid inclusions or differential stress *** the mechanisms responsible for overpressures during geological history is the basic prerequisite for paleo-pressure ***,quantitative studies were conducted of the contributions of disequilibrium compaction,gas charging,oil cracking,temperature reduction,and tectonic uplift and subsidence to *** case studies of paleo-pressure reconstruction were performed for the Sinian strata in the Sichuan Basin,Ordovician strata in the north uplift in the Tarim Basin and the Permian strata in the Sulige Gas Field in the Ordos Basin,where these three study sites are normally pressured,weakly over-pressured and abnormally low pressured at present,*** new method developed in this paper is very important for the practical reconstruction of the paleopressure in marine strata and ancient strata in deep basins.

关键词： Formation pressure Fluid inclusion Differential stress Basin modelling Overpressure Marine basin

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Selective Oxidation of Methane into Methanol Under Mild Conditions

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Chemical Research in Chinese Universities 2022年第3期38卷 671-676页

作者： liu yifeng WANG Liang XIAO Feng-Shou Key Lab of Applied Chemistry of Zhejiang Province Department of ChemistryZhejiang UniversityHangzhou310028P.R.China Key Lab of Biomass Chemical Engineering of Ministry of Education College of Chemical and Biological EngineeringZhejiang UniversityHangzhou310027P.R.China Zhejiang Tianlan Environmental Protection Technology Limited Company Hangzhou310012P.R.China

Selective oxidation of methane to methanol under mild conditions has been considered as a dream reaction but suffers from poor efficiency due to the strong C-H bond of methane and easy overoxidation of the methanol *** overcoming these problems,a series of strategies has been developed for improving methanol productivity with oxidants of hydrogen peroxide and even a mixture of oxygen and hydrogen at mild *** achievements in these strategies using effective catalysts,such as supported metal nanoparticles,colloidal metal nanoparticles,and metal@zeolites are briefly ***,the current challenges,future perspectives for preparing active,selective,and stable catalysts,have been *** zeolite fixed metal nanoparticle structure has been found to boost the reaction by benefiting the formation and enrichment of peroxide intermediates,which might guide the development of more efficient catalysts.

关键词： Methane oxidation Metal@zeolite Hydrogen peroxide Methanol

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食物饱腹感研究及其测试技术进展

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食品科学 2025年第2期46卷 299-307页

作者：姚孟丽韩晓峰王若永韩小伟韩忠曾新安黄京美刘义凤苑鹏柳嘉段盛林中国食品发酵工业研究院北京100020 空军特色医学中心北京100142 中国人民解放军总医院第五医学中心北京100139 华南理工大学食品科学与工程学院广东广州510640

饱腹感,即为进食后满足感和不再渴望进食的状态,在维护正常食欲、控制体质量、预防肥胖及改善代谢性疾病方面具有重要意义。文章系统分析影响饱腹感的多种因素,包括食物成分、感官特征、能量密度、心理因素及饮食行为等,并阐述这些因素... 详细信息

饱腹感,即为进食后满足感和不再渴望进食的状态,在维护正常食欲、控制体质量、预防肥胖及改善代谢性疾病方面具有重要意义。文章系统分析影响饱腹感的多种因素,包括食物成分、感官特征、能量密度、心理因素及饮食行为等,并阐述这些因素对饱腹感的作用机制。同时,重点介绍模拟视觉量表、胃肠道激素检测及闪烁扫描等新兴技术在饱腹感测试中的应用,展示这些技术在评估饱腹感方面的科学性和有效性。此外,文章还讨论饱腹感及其测试技术的研究意义与未来展望,旨在为饱腹感相关机制的深入研究、饱腹感测试技术的创新以及高饱腹感食品的开发提供理论支持和实践参考。

关键词：饱腹感食物成分感官特征能量密度心理因素饮食行为模拟视觉量表生化指标

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Noninvasive preimplantation genetic testing in assisted reproductive technology:current state and future perspectives

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Journal of Genetics and Genomics 2020年第12期47卷 723-726页

作者： Jingyi Li yifeng liu Yuli Qian Dan Zhang Key Laboratory of Reproductive Genetics(Ministry of Education)and Department of Reproductive Endocrinology Women's HospitalZhejiang University School of MedicineHangzhouZhejiang 310006China Key Laboratory of Women's Reproductive Health of Zhejiang Province HangzhouZhejiang 310006China

Invasive genetic screening of pre-implantation embryos via biopsied trophectoderm(TE)cells has been in use for more than 20 years,while its benefits in selecting euploid embryos remain *** advances in the ability to process embryonic cell-free DNA(cfDNA)from blastocoel fluid(BF)and spent culture media(SCM)of blastocysts in a manner similar to that of a biopsied TE sample provide a potential alternative holding great promise for obtaining cytogenetic information of the embryos without intrusive biopsy of traditional biopsy-based pre-implantation genetic testing(PGT).Several studies have reported even higher diagnostic accuracy in non-invasive PGT(ni-PGT)than conventional ***,there are still several technical challenges to be overcome before ni-PGT can be accepted as a reliable genomic information source of *** this review,we have summarized the emergence and current state of ni-PGT,and discussed our own perspectives on their limitations and future *** is still a long way to go before truly wide clinical application of ni-PGT.

关键词： Pre-implantation genetic testing Spent culture media Blastocoel fluid Cell-free DNA Non-invasive PGT

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Lateral shear performance of sheathed post-and-beam wooden structures with small panels

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Frontiers of Structural and Civil Engineering 2023年第7期17卷 1117-1131页

作者： Weiguo LONG Wenfan LU yifeng liu Qiuji LI Jiajia OU Peng PAN China Southwest Architectural Design and Research Institute Co.Ltd. Chengdu 610042China Civil Engineering Department Tsinghua UniversityBeijing 100084China

Sheathed post-and-beam wooden structures are distinct from light-wood *** allow for using sheathing panels that are smaller(0.91 m×1.82 m)than standard-sized panels(1.22 m×2.44 m or 2.44 m×2.44 m).Evidence indicates that nail spacing and panel thickness determine the lateral capacity of the wood frame shear *** verify the lateral shear performance of wood frame shear walls with smaller panels,we subjected 13 shear walls,measuring 0.91 m in width and 2.925 m in height,to a low-cycle cyclic loading test with three kinds of nail spacing and three panel thicknesses.A nonlinear numerical simulation analysis of the wall was conducted using ABAQUS finite element(FE)software,where a custom nonlinear spring element was used to simulate the sheathing-frame *** results indicate that the hysteretic performance of the walls was mainly determined by the hysteretic performance of the sheathing-frame *** same nail specifications were adopted,the stiffness and bearing capacity of the walls were inversely related to the nail spacing and directly related to the panel *** shear wall remained in the elastic stage when the drift was 1/250 rad and ductility coefficients were all greater than 2.5,which satisfied the deformation requirements of residential *** on the test and FE analysis results,the shear strength of the post-and-beam wooden structures with sheathed walls was determined.

关键词： post-and-beam wooden structures with sheathed walls low reversed cyclic loading bearing capacity stiffness numerical simulation

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DC Current Order Optimization Based Strategy for Recovery Performance Improvement of LCC-HVDC Transmission Systems

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Journal of Modern Power Systems and Clean Energy 2023年第3期11卷 1020-1026页

作者： Renlong Zhu Xiaoping Zhou Shuchen Luo Lerong Hong Hanhang Yin yifeng liu College of Electrical and Information Engineering Hunan UniversityChangsha 410082China State Grid Hunan Electric Power Company Limited Economical and Technical Research Institute Changsha 410011China

For the safe and fast recovery of line commutated converter based high-voltage direct current(LCC-HVDC)transmission systems after faults,a DC current order optimization based strategy is *** the constraint of electric and control quantities,the DC current order with the maximum active power transfer is calculated by Thevenin equivalent parameters(TEPs)and quasi-state equations of LCC-HVDC transmission ***,to mitigate the subsequent commutation failures(SCFs)that may come with the fault recovery process,the maximum DC current order that avoids SCFs is calculated through imaginary commutation ***,the minimum value of the two DC current orders is sent to the control *** results based on PSCAD/EMTDC show that the proposed strategy mitigates SCFs effectively and exhibits good performance in recovery.

关键词： Line commutated converter(LCC) high-voltage direct current(HVDC) DC current order calculation subsequent commutation failure(SCF) recovery

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Quantitative distinction of the relative actions of climate change and human activities on vegetation evolution in the Yellow River Basin of China during 1981-2019

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Journal of Arid Land 2023年第1期15卷 91-108页

作者： liu yifeng GUO Bing LU Miao ZANG Wenqian YU Tao CHEN Donghua School of Civil Architectural Engineering Shandong University of TechnologyZibo 255000China Key Laboratory of Urban Land Resources Monitoring and Simulation Ministry of Natural ResourcesShenzhen 518000China Key Laboratory of National Geographic Census and Monitoring Ministry of Natural ResourcesWuhan 430072China Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100101China State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Key Laboratory of Agricultural Remote Sensing Ministry of Agriculture and Rural Affairs/Institute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural SciencesBeijing 100081China Zhongke Langfang Institute of Spatial Information Applications Langfang 065000China College of Computer and Information Engineering Chuzhou UniversityChuzhou 239000China

Under the combined influence of climate change and human activities,vegetation ecosystem has undergone profound *** can be seen that there are obvious differences in the evolution patterns and driving mechanisms of vegetation ecosystem in different historical ***,it is urgent to identify and reveal the dominant factors and their contribution rates in the vegetation change *** on the data of climate elements(sunshine hours,precipitation and temperature),human activities(population intensity and GDP intensity)and other natural factors(altitude,slope and aspect),this study explored the spatial and temporal evolution patterns of vegetation NDVI in the Yellow River Basin of China from 1989 to 2019 through a residual method,a trend analysis,and a gravity center model,and quantitatively distinguished the relative actions of climate change and human activities on vegetation evolution based on Geodetector *** results showed that the spatial distribution of vegetation NDVI in the Yellow River Basin showed a decreasing trend from southeast to *** 1981-2019,the temporal variation of vegetation NDVI showed an overall increasing *** gravity centers of average vegetation NDVI during the study period was distributed in Zhenyuan County,Gansu Province,and the center moved northeastwards from 1981 to *** 1981-2000 and 2001-2019,the proportion of vegetation restoration areas promoted by the combined action of climate change and human activities was the *** the study period(1981-2019),the dominant factors influencing vegetation NDVI shifted from natural factors to human *** results could provide decision support for the protection and restoration of vegetation ecosystem in the Yellow River Basin.

关键词： vegetation evolution driving mechanisms climate change human activities relative actions Geodetector Yellow River Basin

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Guided Dropout: Improving Deep Networks Without Increased Computation

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Intelligent Automation & Soft Computing 2023年第6期36卷 2519-2528页

作者： yifeng liu Yangyang Li Zhongxiong Xu Xiaohan liu Haiyong Xie Huacheng Zeng National Engineering Research Center for Risk Perception and Prevention(NERC-RPP) CAEITBeijing100041China University of Science and Technology of China HefeiAnhui230026China Department of Computer Science and Engineering Michigan State UniversityEast LansingMI48824USA

Deep convolution neural networks are going deeper and ***-ever,the complexity of models is prone to overfitting in ***,one of the crucial tricks,prevents units from co-adapting too much by randomly drop-ping neurons during *** effectively improves the performance of deep net-works but ignores the importance of the differences between *** optimize this issue,this paper presents a new dropout method called guided dropout,which selects the neurons to switch off according to the differences between the convo-lution kernel and preserves the informative *** uses an unsupervised clus-tering algorithm to cluster similar neurons in each hidden layer,and dropout uses a certain probability within each *** this would preserve the hidden layer neurons with different roles while maintaining the model’s scarcity and gen-eralization,which effectively improves the role of the hidden layer neurons in learning the *** evaluated our approach compared with two standard dropout networks on three well-established public object detection *** results on multiple datasets show that the method proposed in this paper has been improved on false positives,precision-recall curve and average precision without increasing the amount of *** can be seen that the increased performance of guided dropout is thanks to shallow learning in the *** concept of guided dropout would be beneficial to the other vision tasks.

关键词： Neural network guided dropout object detection shallow learning

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Commutation Failure Mitigation Method Based on Imaginary Commutation Process

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Journal of Modern Power Systems and Clean Energy 2022年第5期10卷 1413-1422页

作者： Renlong Zhu Xiaoping Zhou Haitao Xia Lerong Hong Hanhang Yin Lingfeng Deng yifeng liu College of Electrical and Information Engineering Hunan UniversityChangsha 410082China

The commutation failure(CF) mitigation effectiveness is normally restricted by the delay of extinction angle(EA)measurement or the errors of existing prediction methods for EA or firing angle(FA). For this purpose, this paper proposes a CF mitigation method based on the imaginary commutation process. For each sample point, an imaginary commutation process is constructed to simulate the actual commutation ***, the imaginary EA is calculated by comparing the imaginary supply voltage-time area and the imaginary demand voltage-time area, which can update the imaginary EA earlier than the measured EA. In addition, the proposed method considers the impacts of commutation voltage variation, DC current variation, and phase angle shift of commutation voltage on the commutation process, which can ensure a more accurate EA calculation. Moreover, the DC current prediction is proposed to improve the CF mitigation performance under the single-phase AC faults. Finally, the simulation results based on CIGRE model prove that the proposed method has a good performance in CF mitigation.

关键词： Commutation failure(CF) commutation failure mitigation extinction angle line commutated converter based high-voltage direct current(LCC-HVDC)

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Cenozoic Magmatism and Tectonic Framework of Western Yunnan,China：Constrained from Geochemistry,Sr-Nd-Pb Isotopes and Fission Track Dating

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Acta Geologica Sinica(English Edition) 2016年第5期90卷 1679-1698页

作者： YANG Xin XU Xuhui ZHANG Zhongpei liu yifeng ZHANG Jibiao liu Xingwang XIONG Ping ZHENG Jianjing SINOPEC Petroleum Exploration and Development Research Institute Beijing 100083 China Gansu Provincial Key Laboratory of Petroleum Resources Key Laboratory of Petroleum Resources Research Institute of Geology and Geophysics Chinese Academy of Sciences Lanzhou 730000 China Wuxi Institute of Petroleum Geology SINOPEC Wuxi Jiangsu 214126 China State Key Laboratory of Petroleum Resource and Prospecting China University of Petroleum Beijing 102249 China

Western Yunnan is composed of several extruded continental microblocks that were generated by the oblique collision between the Indian and Asian continents during the *** this study,the magmatic and tectonic frameworks of western Yunnan in the Cenozoic were analyzed based on geochemistry,Sr-Nd-Pb isotopes,and apatite/zircon fission track *** during the Cenozoic in western Yunnan was then divided into three distinctive episodes：alkali granite rocks produced from 55 to 46 Ma were derived from the anatexis of crustal materials;bimodal igneous rocks formed between 37 and 24 Ma were possibly derived from an EMII mantle with a contribution from continental materials;and intermediate-basic volcanic rocks produced in the Tengchong microblocks since-16 Ma are considered to be generated by the partial melting of the upper mantle that was induced by the pulling apart of the dextral Gaoligong strike-slip fault ***,fission track analysis of apatite and zircon indicates that the regional crustal uplift in western Yunnan possibly began at -34 Ma,with accelerated annealing occurring at -24 Ma,-13 Ma,and -4 *** the past24 Ma,the average denudation rate was -0.32 mm/yr for the faulted block controlled by the Chongshan-Lancang River ***,crustal uplift has been relatively gentle in places lacking influence from strike-slip shear zones,with an average denudation rate of-0.2 mm/*** with strike-slip shear and block rotation in the Cenozoic,the tectonic evolution of western Yunnan since -45Ma can thus be divided into four stages occurring at 45-37 Ma,37-24 Ma,24-13 Ma,and 13-0 Ma.

关键词： Magmatism Geochemistry Fission Track Dating Cenozoic Western Yunnan

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