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Dynamic steric confinement effect expands the frontier of Cu-catalyzed asymmetric propargylic aminations

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Science China Chemistry 2024年第10期67卷 3181-3183页

作者： peng Chen mao-mao Zhang Wen-Jing Xiao Liang-Qiu Lu Engineering Research Center of Photoenergy Utilization for Pollution Control and Carbon Reduction Ministry of EducationCollege of ChemistryCentral China Normal UniversityWuhan 430079China Wuhan Institute of Photochemistry and Technology Wuhan 430082China State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical Physics(LICP)Chinese Academy of SciencesLanzhou 730000China School of Chemistry and Chemical Engineering Henan Normal UniversityXinxiang 453007China

Chiralα-tertiary amines and related azacycles are commonly found in many natural products,pharmaceuticals and agrochemicals[1].Copper-catalyzed asymmetric propargylic amination(APA)reactions have been established as a reliable method to access enantio-enriched propargylic amines,largely due to the seminal contribution of Nishibayashi et al.[2]and van Maarseveen et al.[3]in 2008.

关键词： catalyzed asymmetric amines

Simulation of RFI Cancellation Using Subspace Projection Algorithm for PAF Receiver

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Research in Astronomy and Astrophysics 2024年第1期24卷 237-244页

作者： peng Wu Jian Li mao-Zheng Chen Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China University of Chinese Academy of Sciences Beijing 100049China Xinjiang Key Laboratory of Microwave Technology Urumqi 830011China

The simulation of radio frequency interference(RFI) cancellation by applying a spatial filtering technique for phased array feed(PAF) is presented. In order to better reflect the characteristics of PAF, a new signal model is to add the coupling coefficient among elements of PAF to the conventional array signal model. Then the subspace projection(SP) algorithm is used to cancel RFI from the correlation matrix of the signal, and finally, the 2D power image is drawn. The power variation of signal-of-interest direction and RFI direction before and after using the SP algorithm is analyzed. The new signal model and simulation strategy can be used to test and verify the beamformer.

关键词： methods:analytical techniques:radar astronomy telescopes

Simulation of Underground Reservoir Stability of Pumped Storage Power Station Based on Fluid-Structure Coupling

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Computer Modeling in Engineering & Sciences 2024年第5期139卷 1381-1399页

作者： peng Qiao shuangshuang Lan Hongbiao Gu Zhengtan mao Faculty of Architecture Civil and Transportation EngineeringBeijing University of TechnologyBeijing100020China College of Transportation Engineering Nanjing Tech UniversityNanjing210000China

Based on global initiatives such as the clean energy transition and the development of renewable energy,the pumped storage power station has become a new and significant way of energy storage and regulation,and its construction environment is more complex than that of a traditional *** particular,the stability of the rock strata in the underground reservoirs is affected by the seepage pressure and rock stress,which presents some challenges in achieving engineering safety and *** the advantages of the numerical simulation method in dealing deal with nonlinear problems in engineering stability,in this study,the stability of the underground reservoir of the shidangshan(SDS)pumped storage power station was numerically calculated and quantitatively analyzed based on fluid-structure coupling theory,providing an important reference for the safe operation and management of the underground ***,using the COMSOL software,a suitablemechanicalmodel was created in accordance with the geological structure and project characteristics of the underground ***,the characteristics of the stress field,displacement field,and seepage field after excavation of the underground reservoir were simulated in light of the seepage effect of groundwater on the nearby rock of the underground ***,based on the construction specifications and Molar-Coulomb criterion,a thorough evaluation of the stability of the underground reservoir was performed through simulation of the filling and discharge conditions and anti-seepage strengthening *** findings demonstrate that the numerical simulation results have a certain level of reliability and are in accordance with the stress measured in the project *** underground reservoir excavation resulted in a maximum displacement value of the rock mass around the caverns of 3.56 mm in a typical section,and the safety coefficient of the parts,as determined using the Molar-Coulomb criterion,was highe

关键词： Underground reservoir fluid-structure coupling numerical simulation pumped storage power station filling and discharge

Co-influence of the start of thermal growing season and precipitation on vegetation spring green-up on the Tibetan Plateau

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Advances in Climate Change Research 2024年第2期15卷 327-337页

作者： Chen-peng WANG Meng-Tian HUANG Pan-mao ZHAI State Key Laboratory of Severe Weather and Institute of Global Change and Polar Meteorology Chinese Academy of Meteorological SciencesBeijing 100081China University of Chinese Academy of Sciences Beijing 100049China

The climate in the Tibetan Plateau(TP)has undergone significant change in recent decades,mainly in thermal and water conditions,which plays a crucial role in phenological changes in vegetation spring ***,how the start of the thermal growing season(SOS-T)and the start of the rainy season(SORS)as key climatic factors affect vegetation green-up remains *** that these factors characterize thermal and water conditions required for vegetation green-up,this study investigated changes in the SOS-T and SORS from 1961 to 2022,using observation-based datasets with long time *** found that the SOS-T and SORS have advanced across the TP in 1961-2022 and have shown a spatial pattern of advancement in the east and delay in the west in ***,the co-effect of temperature and precipitation change on the start of vegetation growing season(SOS-V)in 2000-2022 was *** across TP,the SOS-V had an early onset of 1.3 d per decade during 2000-2022,corresponding to advanced SOS-T and ***,the SOS-V generally occurred nearly at the same time as the SOS-T in the high-altitude meadow region.A substantial delay in the SOS-V relative to the SOS-T was observed in the desert,shrub,grassland and forest regions and generally kept pace with the ***,for 50%of the vegetated regions on the TP,inter-annual variation in the delay in the SOS-V relative to the SOS-T was dominated by precipitation change,which was profound in warm-climate *** study highlights the co-regulation of precipitation and temperature change in the SOS-V in different vegetation cover regions in the TP,offering a scientific foundation for comprehending the impact of climate change and prospects for vegetation phenology on the TP.

关键词： Tibetan Plateau Start of growing season Temperature Precipitation Climate change

Light sheet fluorescence microscopy: Advancing biological discovery with more dimensions, higher speed, and lower phototoxicity

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The Innovation 2024年第5期5卷 29-30页

作者： Yao Zhou shiqi mao peng Fei School of Optical and Electronic Information-Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China Advanced Biomedical Imaging Facility Huazhong University of Science and TechnologyWuhan 430074China

TO SEE THE WORLD IN A GRAIN OF *** microscopy has proved to be essential for seeing life in a grain of a *** epifluorescence microscopes,such as wide-field microscopes and laser scanning confocal microscopes,have been widely used for biology research over the past few *** goal of fluorescence microscopy is to observe the structure and function of cellular events across time and threedimensional(3D)space with spatiotemporal resolution as high as ***,conventional epifluorescence microscopes illuminate the entire 3D volume of the sample while detecting signals only from the 2D focal plane,thereby leading to low photon utilization and high phototoxicity issues that notably prevent high-resolution imaging of live biological specimens(Figure 1A).It becomes increasingly noteworthy that the massively emerging biomedical applications are posing significant challenges to current fluorescence microscopy techniques.

关键词： fluorescence dimensions Figure

Mechanical properties and fracture surface roughness of thermally damaged granite under dynamic splitting

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Deep Underground Science and Engineering 2024年第1期3卷 103-116页

作者： Yijin Qian peng Jia Songze mao Jialiang Lu School of Resources and Civil Engineering Northeastern UniversityShenyangChina

In order to understand the mechanical properties and the fracture surface roughness characteristics of thermally damaged granite under dynamic splitting,dynamic Brazilian splitting tests were conducted on granite samples after thermal treatment at 25,200,400,and 600℃.Results show that the dynamic peak splitting strength of thermally damaged granite samples increases with increasing strain rate,showing obvious strain‐rate *** increasing temperature,thermally induced cracks in granite transform from intergranular cracks to intragranular cracks,and to a transgranular crack *** induced damages reduce the dynamic peak splitting strength and the maximum absorbed energy while increasing the peak radial *** fracture mode of the thermally damaged granite under dynamic loads is mode Ⅱ splitting *** using the axial roughness index Z2 a,the distribution ranges of the wedge‐shaped failure zones and the tensile failure zones in the fracture surfaces under dynamic Brazilian splitting can be effectively *** radial roughness index Z_(2)^(r)is sensitive to the strain rate and *** shows a linear correlation with the peak splitting strength and the maximum absorbed energy and a linear negative correlation with the peak radial strain.Z_(2)^(r)can be used to quantitatively estimate the dynamic parameters based on the models proposed.

关键词： dynamic splitting fracture surface roughness granite strain rate thermal treatment

Novel soft robotic finger model driven by electrohydrodynamic(EHD)pump

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第7期25卷 596-604页

作者： Xuehang BAI Yanhong peng Dongze LI Zhuochao LIU Zebing mao Department of Mechanical Automotive and Materials EngineeringFaculty of EngineeringUniversity of WindsorWindsorN9B 3P4Canada Department of Information and Communication Engineering Graduate School of EngineeringNagoya UniversityNagoya464-8601Japan Department of Intelligent Science and Technology College of Computer Science and TechnologyQingdao UniversityQingdao266071China Design and Research Institute of University of Science and Technology Beijing Co.Ltd. Beijing100083China Faculty of Engineering Yamaguchi UniversityYamaguchi755-8611Japan

1Introduction In the field of robotic-human interactions,soft robotics offers enhanced safety and adaptability.A major challenge in this area is the integration of soft actuators with pump systems,which often increases the system volume and *** study presents the development and testing of a robotic finger powered by electrohydrodynamic(EHD)*** leveraging the electric field-induced flow of dielectric fluids.

关键词： robotic complexity. pump

Responses of arbuscular mycorrhizal fungi to straw return and nitrogen fertilizer reduction in a rainfed maize field

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Pedosphere 2024年第2期34卷 351-360页

作者： Zhenling peng Hao XI Lin mao Huyuan FENG Jianjun ZHANG Yongjun LIU State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems College of EcologyLanzhou UniversityLanzhou 730000China College of Life Sciences Northwest Normal UniversityLanzhou 730070China School of Life Sciences Lanzhou UniversityLanzhou 730000China Dryland Agriculture Institute Gansu Academy of Agricultural SciencesLanzhou 730070China

Straw return can be used to reduce fertilizer input and improve agricultural sustainability and soil ***,how straw return and reduced fertilizer application affect beneficial soil microbes,particularly arbuscular mycorrhizal fungi(AMF),remains poorly ***,we conducted a five-year field experiment in a rainfed maize field on the Loess Plateau of northwestern *** tested four treatments with straw return combined with four nitrogen(N)application rates,i.e.,100%,80%,60%,and 0%of the common N application rate(225 kg N ha^(-1)year^(-1))in this region,and two reference treatments(full or no N application),with three replicates for each *** colonization was quantified and AMF communities colonizing maize roots were characterized using Illumina *** virtual taxa(VTs)of AMF were identified in root samples,among which VT113(related to Rhizophagus fasciculatus)and VT156(related to Dominikia gansuensis)were the predominant *** root length colonization and AMF VT richness were sensitive to N fertilization,but not to straw return;furthermore,both gradually increased with decreasing N application *** VT composition of the AMF community was also affected by N fertilization,but not by straw return,and the community variation could be well explained by soil available N and phosphorus ***,60%,80%,and full N fertilization produced similar maize ***,our study revealed the response patterns of AMF to straw return and N fertilizer reduction and showed that straw return combined with N fertilizer reduction may be a promising practice to maintain mycorrhizal symbiosis concomitantly with crop productivity.

关键词： agricultural sustainability crop productivity mycorrhizal colonization mycorrhizal symbiosis root length colonization virtual taxon

Efficacy and predictive factors of transarterial chemoembolization combined with lenvatinib plus programmed cell death protein-1 inhibition for unresectable hepatocellular carcinoma

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World Journal of Gastrointestinal Oncology 2024年第4期16卷 1236-1247页

作者： Kun-peng Ma Jin-Xin Fu Feng Duan mao-Qiang Wang Department of Interventional Radiology The Fifth Medical Center of Chinese People's Liberation Army General HospitalBeijing 100853China Chinese People's Liberation Army Medical School Beijing 100853China

BACKGROUND The efficacy and safety of transarterial chemoembolization(TACE)combined with lenvatinib plus programmed cell death protein-1(PD-1)for unresectable hepato-cellular carcinoma(HCC)have rarely been evaluated and it is unknown which factors are related to *** To evaluate the efficacy and independent predictive factors of TACE combined with lenvatinib plus PD-1 inhibitors for unresectable *** This study retrospectively enrolled patients with unresectable HCC who received TACE/lenvatinib/PD-1 treatment between March 2019 and April *** survival(OS)and progression-free survival(PFS)were *** objective response rate(ORR)and disease control rate(DCR)were evaluated in accordance with the modified Response Evaluation Criteria in Solid ***,the prognostic factors affecting the clinical outcome were *** One hundred and two patients were enrolled with a median follow-up duration of 12.63 *** median OS was 26.43 months(95%CI:17.00-35.87),and the median PFS was 10.07 months(95%CI:8.50-11.65).The ORR and DCR were 61.76%and 81.37%,*** patients with Barcelona Clinic Liver Cancer Classification(BCLC)B stage,early neutrophil-to-lymphocyte ratio(NLR)response(decrease),or early alpha-fetoprotein(AFP)response(decrease>20%)had superior OS and PFS than their *** This study showed that TACE/lenvatinib/PD-1 treatment was well tolerated with encouraging efficacy in patients with unresectable *** patients with BCLC B-stage disease with early NLR response(decrease)and early AFP response(decrease>20%)may achieve better clinical outcomes with this triple therapy.

关键词： Transarterial chemoembolization Efficacy Lenvatinib Programmed cell death protein-1 inhibitors Unresectable hepatocellular carcinoma