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Air pressure law of a reservoir constructed in karst sinkholes

Journal of Mountain Science 2024年第3期21卷 1048-1057页

作者： yU Bo TAI Shengping zheng Kexun CHEN Shiwan HAN xiao WANG Senlin ZUO Shuangying Power China Guiyang Engineering Corporation Limited Guiyang 550081China College of Resources and Environmental Engineering Key Laboratory of Karst Georesources and EnvironmentMinistry of EducationGuizhou UniversityGuiyang 550025China

Karst sinkholes with natural negative landform provide favorable conditions for the pumped storage reservoir construction for less excavation ***,the construction of the reservoir would plug the natural karst channels for water and air,which would cause remarkable air pressure in karst channels when the groundwater level fluctuates.A large laboratory simulation test was carried out to study the air pressure variation of a reservoir built on the karst *** air pressure in the karst channel and inside the model was monitored during the groundwater rising and falling *** showed that the variation of air pressure in the karst channel and the surrounding rock exhibited a high degree of *** air pressure increased rapidly at the initial stage of water level rising,followed by a slight decrease,then the air pressure increased sharply when the water level approached the top of the karst *** initial peak of air pressure and the final peak of air pressure were defined,and both air pressure peaks were linearly increasing with the water level rising *** negative air pressure was also analyzed during the drainage process,which was linearly correlated with the water level falling *** causes of air pressure variation in karst channels of a pumped storage reservoir built on the karst sinkhole were *** initial rapid increase,then slight decrease and final sudden increase of air pressure were controlled by the combined effects of air compression in karst channel and air seepage into the surrounding *** the drainage process,the instant negative air pressure and gradual recovering of air pressure were controlled by the combined effects of negative air pressure induced by water level falling and air supply from surrounding *** work could provide valuable reference for the reservoir construction in karst area.

关键词： Simulation test Karst sinkhole Pumped storage reservoir Air pressure Flow rate

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Sorely reducing emissions of non-methane short-lived climate forcers will worsen compound flood-heatwave extremes in the Northern Hemisphere

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Advances in Climate Change Research 2024年第4期15卷 737-750页

作者： ying-Fang LI Zhi-Li WANG ya-Dong LEI xiao-Chao yU Lin LIU Hui-zheng CHE xiao-ye ZHANG State Key Laboratory of Severe Weather and Key Laboratory of Atmospheric Chemistry of China Meteorological Administration Chinese Academy of Meteorological SciencesBeijing 100081China University of Chinese Academy of Sciences Beijing 100190China

Non-methane short-lived climate forcer(SLCF)or near-term climate forcer(NTCF)emissions,as a significant driver of climate change,can be reduced to improve air *** reductions may contribute to additional warming of the climate system in the short term,thereby strongly affecting the likelihood of climate ***,there has been no quantitative assessment of the impact of non-methane SLCF mitigation on compound flood-heatwave extremes(CFHEs).This study quantitatively investigates the changes in future(2031-2050 versus 1995-2014)CFHEs and the resulting population exposure in the Northern Hemisphere(NH)due to non-methane SLCF *** used multi-model ensemble simulations under two future scenarios from the Aerosol and Chemistry Model Intercomparison Project(AerChemMIP)in the Coupled Model Intercomparison Project Phase 6(CMIP6).The two future scenarios share the same greenhouse gas(GHG)emissions but have weak(Shared Socioeconomic Pathway(SSP)3-7.0)versus strong(SSP3-7.0-lowNTCF)levels of air quality control *** results show that future non-methane SLCF reductions during 2031-2050 results in about a 7.3%±2.3%increase in grid exposure to CFHEs in the NH relative to the period *** frequency,intensity.and duration of CFHEs increase by varying *** the period 2031-2050,the frequency of CFHEs across the NH increases by 2.9±0.9 events per decade due to non-methane SLCF *** increases in CFHE frequency are more pronounced in East Asia,South Asia,Siberia,and northern and eastern North *** East and South Asia,the in-tensities of both heatwaves and floods corresponding to CFHEs increase markedly,where heatwave magnitude(HWM)increases by 0.3±0.2 K in East Asia and weighted average precipitation(WAP)increases by 18.3%±15.3%and 12.0%±4.5%in East Asia and South Asia,*** other regions,rising temperatures dominate the increase in *** regard to the duration of CFHEs,future reductions in non-methane SLC

关键词： Non-methane SLCFs CHFEs Cleaner air Population exposure

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Microstructure and Mechanical Behavior of Mg-Based Bimetal Plates with High Formability Sleeve by Co-extrusion

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 499-512页

作者： yue-Hui Dang Sheng-Lin Liu xiao-Lei Ai xiao-Wei Feng Bo Feng Zhuo Tian ying-Fei Lin Huan-Tao Chen Kai-Hong zheng School of Materials Science and Engineering Chang’an UniversityShaanxi 710064China Guangdong Key Laboratory of Metal Toughening Technology.and Application Institute of New MaterialsGuangdong Academy of SciencesGuangzhou 510650China

In this study,microstructure and mechanical behavior of two types of Mg-based bimetal plates with a high formability sleeve were systematically studied,with a great emphasis on the effect of the interface characteristic and the sleeve fraction on the plasticity of composite *** rule of mixtures(ROM)for elongation was also *** results show that when there is no or thin diffusion layer with thickness of about 3μm,Mg-based bimetal plates have a good plasticity with elongation of about 19-24%,and the ROM predicted elongations are very close to the experimental *** contrast,with a diffusion layer about 95-155μm thick,Mg-based bimetal plates exhibit a poor plasticity with elongation of about 11-17%,and the experimental elongations largely deviate from the ROM *** plasticity of Mg-based bimetal plates increases with increasing sleeve *** study provides new insights on the plastic deformation of Mg-based bimetal composites with a high formability sleeve.

关键词： Mg-based composites Co-extrusion Microstructure Mechanical behavior Plastic deformation

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Progress in the treatment of advanced hepatocellular carcinoma with immune combination therapy

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World Journal of Gastrointestinal Oncology 2024年第2期16卷 273-286页

作者： Di Pan Hao-Nan Liu Peng-Fei Qu xiao Ma Lu-yao Ma xiao-xiao Chen yu-Qin Wang xiao-Bing Qin zheng-Xiang Han Department of Oncology The Affiliated Hospital of Xuzhou Medical UniversityXuzhou 221000Jiangsu ProvinceChina Department of Gastroenterology The Second Affiliated Hospital of Xuzhou Medical UniversityXuzhou 221000Jiangsu ProvinceChina Department of General Surgery The Affiliated Hospital of Xuzhou Medical UniversityXuzhou 221000Jiangsu ProvinceChina

Advanced hepatocellular carcinoma(HCC)is a severe malignancy that poses a serious threat to human *** to challenges in early diagnosis,most patients lose the opportunity for radical treatment when ***,recent advancements in cancer immunotherapy provide new directions for the treatment of *** instance,monoclonal antibodies against immune check-point inhibitors(ICIs)such as programmed cell death protein 1/death ligand-1 inhibitors and cytotoxic t-lymphocyte associated antigen-4 significantly improved the prognosis of patients with ***,tumor cells can evade the immune system through various *** the rapid development of genetic engineering and molecular biology,various new immunotherapies have been used to treat HCC,including ICIs,chimeric antigen receptor T cells,engineered cytokines,and certain cancer *** review summarizes the current status,research progress,and future directions of different immunotherapy strategies in the treatment of HCC.

关键词： Hepatocellular carcinoma Immunotherapies Immune checkpoint inhibitor Clinical efficacy Adverse reactions

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Photoredox-Catalyzed Metal-Free Regio-&Stereoselective C(sp^(2))-H Amination of Enamides with N-Aminopyridium Salts

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Chinese Journal of Chemistry 2024年第18期42卷 2235-2242页

作者： zheng-Bao Qin Kun Ni Li Wang xiao-Di Wu yu Zhang Kai Zhao Institute of Advanced Synthesis School of Chemistry and Molecular EngineeringJiangsu National Synergetic Innovation Center for Advanced MaterialsNanjing Tech UniversityNanjingJiangsu211816China college of Chemical Engineering Nanjing Forestry UniversityNanjingJiangsu 210037China

A visible-light-induced photoredox-catalyzed regioselective and stereoselective C(sp')-H amination of enamides with bench-stable and A visible-light-induced photoredox-catalyzed regioselective and stereoselective C(sp)-H amination of enamides with bench-stable and easily accessible N-aminopyridium salts is developed,affording synthetically.and biologically prominent vicinal 1,2-diamine scaffolds with broad substrate scope and excellent functional group *** transformation proceeded through a radical pathway involving the Giese addition of the relatively electrophilic N-centered sulfonamidyl radical species to nucleophilicβ-olefinic position of enamides followed by the ensuing single electron oxidation andβ-H elimination,delivering geometrically-defined Z-configuredβ-sulfonamidylated *** operational simplicity,environmental friendliness and cost efficiency of this methodology allowed it to pave a new avenue to enrich the arsenal of synthetically crucial functionalized enamides and their related derivatives.

关键词： Enamides Amination Photoredox catalysis Regioselective Stereoselective Metal-free

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An improved installation of 2-hydroxy-4-methoxybenzyl(iHmb)method for chemical protein synthesis

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Chinese Chemical Letters 2024年第5期35卷 145-150页

作者： ying Li Long-Jie Wang yong-Kang Zhou Jun Liang Bin xiao Ji-Shen zheng The First Affiliated Hospital of USTC MOE Key Laboratory for Membraneless Organelles and Cellular DynamicsDivision of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefei 230001China Department of Chemistry University of Science and Technology of ChinaHefei 230027China

The 2-hydroxy-4-methoxybenzyl(Hmb)backbone modification can prevent amide bond-mediated sidereactions(e.g.,aspartimide formation,peptide aggregation)by installing the removable Hmb group into a peptide bond,thus improving the synthesis of long and challenging peptides and ***,its use is largely precluded by the limited Hmb’s installation *** this report,an improved installation of Hmb(iHmb)method was developed to achieve the flexible installation and the convenient removal of *** iHmb method involves two critical steps:(1)oxidative diazotization of the readily installed 2-hydroxy-4-methoxy-5-amino-benzyl(Hmab)to give 2-hydroxy-4-methoxy-5-diazonium-benzyl(Hmdab)by combining soamyl nitrite(IAN)/HBF_(4),and(2)reductive elimination of Hmdab to give the desired Hmb by 1,2-ethanedithiol(EDT).The iHmb method enables the installation of Hmb at any primary amino acid including the highly sterically hindered amino acids(e.g.,valine and isoleucine).The practicality.and utility of the iHmb method was demonstrated by one-shot solid-phase synthesis of a challenging aspartimide-prone peptide,the mirror-image version of a hydrophobic peptide and a long-chain peptide up to ***,the iHmb method can be utilized to facilitate chemical protein ligation,as exemplified by the synthesis of the single-spanning membrane protein *** iHmb method expands the toolkit for peptide synthesis and ligation and facilitates the preparation of peptides/proteins.

关键词： Chemical protein synthesis Solid-phase peptide synthesis Removable backbone modification 2-Hydroxy-4-methoxybenzyl(Hmb)group Aspartimide-prone peptides Difficult peptides Membrane proteins

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Transient Voltage Support Strategy of Grid-forming Medium Voltage Photovoltaic Converter in the LCC-HVDC System

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CSEE Journal of Power and Energy Systems 2024年第5期10卷 1849-1864页

作者： Hong Lu Xianyong xiao Guangfu Tang Zhiy.an He Zhiguang Lin Chong Gao Zixuan zheng College of Electrical Engineering Sichuan UniversityChengdu 610065China State Key Lab of Advance Power Transmission Technology China Electric Power Research InstituteBeijing 100192China College of Electrical Engineering Sichuan UniversityChengdu 610065China.

The participation of photovoltaic(PV)plants in supporting the transient voltage caused by commutation failure in the line-commutated-converter-based high voltage direct current(LCC-HVDC)system is of great significance,as it can enhance the DC transmission ***,it is found that the gridfollowing(GFL)PV converters face the problem of mismatch between reactive power response and transient voltage characteristic when the voltage converts from low voltage to overvoltage,further aggravating the overvoltage ***,this article proposes a transient voltage support strategy based on the gridforming(GFM)medium voltage PV *** proposed strategy takes the advantage of the close equivalent electrical distance between the converter and grid,which can autonomously control the converter terminal voltage through GFM control with adaptive voltage droop *** simulation results show that the proposed strategy can ensure the output reactive power of the PV converter quickly matches the transient voltage characteristic at different stages,indicating that the proposed strategy can effectively support the transient voltage.

关键词： Commutation failure grid-forming(GFM) photovoltaic(PV)converter reactive power response transient voltage

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Rhodium-Catalyzed Regioselective C-O and C-C Bonds Formation of 3-Oxopent-4-enenitriles with Alkynes for the Synthesis of Polysubstituted 2H-Py.ans

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Chinese Journal of Chemistry 2024年第17期42卷 1986-1992页

作者： Kelu yan xiao Liu Jiangwei Wen Qiuyun Li Junjie Wang yang zheng Xiu Wang Key Laboratory of Life-Organic Analysis of Shandong Province School of Chemistry and Chemical EngineeringQufu Normal UniversityQufuShandong273165China Faculty of Chemistry.and Chemical Engineering Yancheng Institute of TechnologyYanchengJiangsu 224051China

The rhodium-catalyzed C-H bond activation and cyclization of 3-oxopent-4-enenitriles with alkynes proceed *** 2H-py.ans with multiple substituents are achieved in good yields through regioselective formation of C-O and C-C *** involving hydroxy-alkynoates resulted in products with a furo[3,4-b]py.an skeleton via further intramolecular ester exchange *** from the traditional"1-oxatrienes pathway",this method for the synthesis of useful 2H-py.ans possesses certain highlights in terms of readily available substrates,stable and easily derivatized products,gentle and convenient operation process,and step and atomeconomy.

关键词： Rhodium/C-H activation 3-Oxopent-4-enenitriles Alkynes 2H-Py.ans Transition metals Regioselectivity Cyclization Comprehensive Summary

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V0405 Dra:A New Deep and Low Mass Ratio Contact Binary with Extremely Fast Decrease in the Orbital Period

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Research in Astronomy.and Astrophysics 2024年第6期24卷 287-293页

作者： Chao-yue Li Lin-Qiao Jiang Jie zheng yi-Man Liu xiao-yu Long Min Sun Han-Lu Zhang xiao-Man Tian School of Science Leshan Normal UniversityLeshan 614000China Center for Applied Optics Research Leshan Normal UniversityLeshan 614000China Key Laboratory of Detection and Application of Space Effect in Southwest Sichuan Leshan 614000China CAS Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Aeronautics Shandong Jiaotong UniversityJinan 250000China

V0405 Dra is a W UMa-type binary *** on the TESS data,we have conducted an orbital period study.and performed a light curve analysis for the *** orbital period study reveals that the O-C curve for V0405 Dra exhibits secular decrease at an extremely high rate of d P/dt=-2.71×10^(-6)day year^(-1),along with periodic variations characterized by.an amplitude of A_(3)=0.0032 day.and a period of P_(3)=1.413 *** orbital periodic change is possibly due to the light-travel time effect resulting from an additional third body in the system,for which we estimate a minimum mass of M_(3)=0.77M_(⊙).By employing the 2013 version of the Wilson-Devinney(W-D)method to synthesize a light curve,we derived photometric solutions indicating that V0405 Dra is a new deep(f=68.7%)and low-mass ratio(q=0.175)contact *** fast decrease in its orbital period is likely caused by mass transfer from the more massive primary star to the less massive secondary star,or due to angular momentum *** further mass transfer and loss of angular momentum,the binary will gradually evolve into a tighter contact configuration,eventually leading to a merger into a single star,following the evolutionary paths suggested for such deep and low mass ratio contact binaries.

关键词： (stars:)binaries(including multiple):close (stars:)binaries:eclipsing stars:individual(V0405 Dra)

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An audio‐based risky flight detection framework for quadrotors

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IET Cyber-Systems and Robotics 2024年第1期6卷 1-14页

作者： Wansong Liu Chang Liu Seyedomid Sajedi Hao Su xiao Liang Minghui zheng Department of Mechanical and Aerospace Engineering University at BuffaloBuffaloNew YorkUSA Department of Civil Structural and Environmental EngineeringUniversity at BuffaloBuffaloNew YorkUSA Department of Mechanical and Aerospace Engineering North Carolina State UniversityRaleighNorth CarolinaUSA

Drones have increasingly collaborated with human workers in some workspaces,such as *** failure of a drone flight may bring potential risks to human beings'life safety during some aerial *** of the most common flight failures is triggered by damaged *** quickly detect physical damage to propellers,recognise risky flights,and provide early warnings to surrounding human workers,a new and compre-hensive fault diagnosis framework is presented that uses only the audio caused by pro-peller rotation without accessing any flight *** diagnosis framework includes three components:leverage convolutional neural networks,transfer learning,and Bayesian ***,the audio signal from an actual flight is collected and trans-ferred into time–frequency ***,a convolutional neural network‐based diagnosis model that utilises these spectrograms is developed to identify whether there is any broken propeller involved in a specific drone ***,the authors employ Monte Carlo dropout sampling to obtain the inconsistency of diagnostic results and compute the mean probability score vector's entropy(uncertainty)as another factor to diagnose the drone ***,to reduce data dependence on different drone types,the convolutional neural network‐based diagnosis model is further augmented by transfer *** is,the knowledge of a well‐trained diagnosis model is refined by using a small set of data from a different *** modified diagnosis model has the ability to detect the broken propeller of the second ***,to reduce the hyperparameters'tuning efforts and reinforce the robustness of the network,Bayesian optimisation takes advantage of the observed diagnosis model performances to construct a Gaussian pro-cess model that allows the acquisition function to choose the optimal network *** proposed diagnosis framework is validated via real experimental flight tests and has a reasonably hig

关键词： aerial robotics deep learning flying robots propeller diagnosis

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