检索结果-南通市图书馆

Remote copper-catalyzed enantioselective substitution of yne-thiophene carbonates

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第4期67卷 1175-1180页

作者： Hao-Dong qian Xiang Li Tingrui Yin wei-Feng qian Chunhui zhao Cuiju Zhu Hao Xu CCNU-uOttawa Joint Research Centre Key Laboratory of Pesticides&Chemical Biology of Ministry of EducationInternational Joint Research Center for Intelligent Biosensing Technology and HealthCollege of ChemistryCentral China Normal UniversityWuhan 430079China

Here,we describe a strategy for the copper-catalyzed asymmetric heteroarylation of yne-thiophene carbonates with indoles via remote *** key to the success of this strategy lies in the design of the alkynyl group at the ortho-position of the heterocycle thiophene,enabling the formation of a triarylmethane moiety via very remote ***,the concept of remote copper-catalyzed asymmetric transformation extends not only to yne-allylic esters but also to yne-aryl *** reaction readily provides a diverse array of chiral triarylmethanes with high efficiency,enantioselectivity,and excellent functional group ***,facile follow-up transformations underscore their potential utility in the synthesis of various enantioenriched building *** mechanistic studies support the plausibility of the remote substitution pathway.

关键词： remote substitution copper catalyst asymmetric catalysis triaryl methanes

Self-initiated static-dynamic state transition behavior and triggering mechanism of strain rockburst using three-dimensional discrete element method

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Underground Space 2024年第3期16卷 143-163页

作者： Yuan qian Cheng zhao Rui wei Rui Zhang Lin Huang Huiguan Chen Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China School of Engineering Tibet UniversityLhasaTibet850000China

The accurate understanding of rockburst mechanism poses a global challenge in the field of rock *** for strain rockburst,achieving self-initiated static-dynamic state transition is a crucial step in the formation of catastrophic ***,the state transition behavior and its impact on rockburst have not received sufficient attention,and are still poorly ***,this study specifically focuses on the state transition behavior,aiming to investigate its abrupt transition process and formation mechanism,and triggering effects on *** facilitate the study,a novel burst rock-surrounding rock combined laboratory test model is proposed and its effectiveness is validated through experiment ***,corresponding numerical models are established using the three-dimensional(3D)discrete element method(DEM),enabling successful simulation of static brittle failure and rockbursts of varying intensities under quasi-static displacement loading ***,through secondary development,comprehensive recording of the mechanical and energy information pertaining to the combined specimen system and its subsystems is *** a result of numerical investigation studies,the elastic rebound dynamic behavior of the surrounding rock was discovered and identified as the key factor triggering rockburst and controlling its *** impact loading on the burst rock,induced by elastic rebound,directly initiates the dynamic processes of rockburst,serving as the direct ***,the transient work and energy convergence towards the burst rock resulting from elastic rebound are recognized as the inherent cause of ***,it has been observed that a larger extent of surrounding rock leads to a stronger elastic rebound,thereby directly contributing to a more intense *** findings can provide novel theoretical insights for the exploring of rockburst mechanism and the development of monitoring and

关键词： Strain rockburst Static-dynamic state transition Self-initiation Triggering mechanism Elastic rebound Discrete element method

Tipping Point Detection Using Reservoir Computing

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Research 2024年第1期2023卷 779-790页

作者： Xin Li Qunxi Zhu Chengli zhao Xuzhe qian Xue Zhang Xiaojun Duan wei Lin College of Science National University of Defense TechnologyChangshaHunan 410073China Research Institute of Intelligent Complex Systems and MOE Frontiers Center for Brain Science Fudan UniversityShanghai 200433China Shanghai Artificial Intelligence Laboratory Shanghai 200232China School of Mathematical Sciences SCMSSCAMand CCSBFudan UniversityShanghai 200433China

Detection in high fidelity of tipping points,the emergence of which is often induced by invisible changes in internal structures or/and external interferences,is paramountly beneficial to understanding and predicting complex dynamical systems(CDSs).Detection approaches,which have been fruitfully developed from several perspectives(e.g.,statistics,dynamics,and machine learning),have their own advantages but still encounter difficulties in the face of high-dimensional,fluctuating ***,using the reservoir computing(RC),a recently notable,resource-conserving machine learning method for reconstructing and predicting CDSs,we articulate a model-free framework to accomplish the detection only using the time series observationally recorded from the underlying unknown CDSs.

关键词： computing record ping

Investigation on cavitating turbulent flow for the twisted NACA66 hydrofoil using a PANS model with helicity modification

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2024年第2期36卷 219-231页

作者： Chen Geng zhao-hui qian Ke-xin Zheng wei-xiang Ye Xian-wu Luo State Key Laboratory of Hydroscience cand Engineering Deparment of Energy and Power EngineeringTsinghua UniversityBeijing 100084China Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 100084China

In the present paper,the unsteady cavitating turbulent flow over the twisted NACA66 hydrofoil is investigated based on an modified shear stress transfer k-ωpartially averaged Navier-Stokes(MSST PANS)model,i.e.,new MSST PANS(NMSST PANS)model,where the production term of kinetic energy in the turbulence model is modified with *** with the experimental data,cavitation evolution and its characteristic frequency are satisfactorily predicted by the proposed NMSST PANS *** is revealed that the interaction among the main flow,the reentrant jets,and sheet cavitation causes the formation of the primary shedding cavity near the mid-span and the secondary shedding cavity at each side of the twisted hydrofoil,and further induces the remarkable pressure gradient around shedding *** with the development of the primary and the secondary shedding cavities,the great pressure gradient associated with large cavity volume variation promotes the vortical flow generation and the spatial deformation of vortex structure during cavitation evolution,and results in the primary and the secondary U-type ***,dynamic mode decomposition(DMD)analysis is utilized to confirm the interaction among the main flow,the main reentrant jet and two side reentrant jets,and *** results indicate that the proposed NMSST PANS model is suitable to simulate the complicated cavitating turbulent flow for various engineering applications.

关键词： Cavitating turbulent flow partially averaged Navier-Stokes(PANS)model hydrofoil numerical simulation

Targeted metabolomics reveals the aberrant energy status in diabetic peripheral neuropathy and the neuroprotective mechanism of traditional Chinese medicine JinMaiTong

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Pharmaceutical Analysis 2024年第2期14卷 225-243页

作者： Bingjia zhao qian Zhang Yiqian He weifang Cao wei Song Xiaochun Liang Department of Traditional Chinese Medicine Peking Union Medical College HospitalPeking Union Medical CollegeChinese Academy of Medical SciencesBeijing100730China Institute of Basic Medicine Sciences Chinese Academy of Medical SciencesBeijing100005China Medical Research Center Peking Union Medical College HospitalPeking Union Medical CollegeChinese Academy of Medical SciencesBeijing100730China

Diabetic peripheral neuropathy (DPN) is a common and devastating complication of diabetes, for which effective therapies are currently lacking. Disturbed energy status plays a crucial role in DPN pathogenesis. However, the integrated profile of energy metabolism, especially the central carbohydrate metabolism, remains unclear in DPN. Here, we developed a metabolomics approach by targeting 56 metabolites using high-performance ion chromatography-tandem mass spectrometry (HPIC-MS/MS) to illustrate the integrative characteristics of central carbohydrate metabolism in patients with DPN and streptozotocin-induced DPN rats. Furthermore, JinMaiTong (JMT), a traditional Chinese medicine (TCM) formula, was found to be effective for DPN, improving the peripheral neurological function and alleviating the neuropathology of DPN rats even after demyelination and axonal degeneration. JMT ameliorated DPN by regulating the aberrant energy balance and mitochondrial functions, including excessive glycolysis restoration, tricarboxylic acid cycle improvement, and increased adenosine triphosphate (ATP) generation. Bioenergetic profile was aberrant in cultured rat Schwann cells under high-glucose conditions, which was remarkably corrected by JMT treatment. In-vivo and in-vitro studies revealed that these effects of JMT were mainly attributed to the activation of adenosine monophosphate (AMP)-activated protein kinase (AMPK) and downstream peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α). Our results expand the therapeutic framework for DPN and suggest the integrative modulation of energy metabolism using TCMs, such as JMT, as an effective strategy for its treatment.

关键词： Diabetic peripheral neuropathy JinMaiTong Energy metabolism Targeted metabolomics Adenosine monophosphate-activated protein kinase

Lipid metabolism analysis in esophageal cancer and associated drug discovery

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Pharmaceutical Analysis 2024年第1期14卷 1-15页

作者： Ruidi Jiao wei Jiang Kunpeng Xu qian Luo Luhua Wang Chao zhao Bionic Sensing and Intelligence Center Institute of Biomedical and Health EngineeringShenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenGuangdong518000China Department of Radiation Oncology National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital&Shenzhen HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeShenzhenGuangdong518116China School of Medicine Southern University of Science and TechnologyShenzhenGuangdong518000China University of Chinese Academy of Sciences Beijing100049China Shenzhen Key Laboratory of Precision Diagnosis and Treatment of Depression Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenGuangdong518000China

Esophageal cancer is an upper gastrointestinal malignancy with a bleak *** is still being explored in depth due to its complex molecular mechanisms of occurrence and *** play a crucial role in cells by participating in energy supply,biofilm formation,and signal transduction processes,and lipid metabolic reprogramming also constitutes a significant characteristic of malignant *** and more studies have found esophageal cancer has obvious lipid metabolism abnormalities throughout its beginning,progress,and treatment *** inhibition of tumor growth and the enhancement of antitumor therapy efficacy can be achieved through the regulation of lipid ***,we reviewed and analyzed the research results and latest findings for lipid metabolism and associated analysis techniques in esophageal cancer,and comprehensively proved the value of lipid metabolic reprogramming in the evolution and treatment resistance of esophageal cancer,as well as its significance in exploring potential therapeutic targets and biomarkers.

关键词： Lipid metabolism Esophageal cancer Progression Treatment resistance New therapeutic targets

Evaluation on cutting performance of novel PDC cutter for pipe jacking machine

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Underground Space 2024年第1期14卷 34-52页

作者： Long-Chuan Deng Yi-Xiang Yuan Xiao-zhao Li qian-wei Zhuang Chi Zhang Yi-wei Chen School of Earth Sciences and Engineering Nanjing UniversityNanjingJiangsu 210023China Shanghai Tunnel Engineering Co.Ltd. Shanghai 200232China State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhouJiangsu 221116China School of Mechanics and Engineering Science Shanghai UniversityShanghai 200444China

It is inevitable to cut reinforced concrete(RC)appeared in cross passage of city metro by cutting tools when constructing in densely populated *** previous cutters employed to cut RC are insufficient and easily damaged,so a new polycrystalline diamond compact(PDC)cutter is used to solve this *** on the theoretical analysis of cutting mechanism,both circular and tapered PDC cutters with cutting edge angle of 90and negative front rack angle of 10are used to cut *** peeling and breaking patterns of cutting concrete are proposed,the nodular and grainy chips are the preferred modes in cutting steel *** LS-DYNA is employed to investigate the cutting performance in *** simulation results show that the average and peak cutting forces increase with the growth of penetration depth,cutting speed,and roundness,and subsequently the recommended penetration depth less than 1.2 mm is obtained to cut RC due to the existence of steel ***,the linear cutting platform is adopted to investigate the force ability and damage state of PDC *** is concluded that the cutting force increases abruptly and fluctuates heavily when cutting the coarse *** patterns occurred in both numerical and experimental results are generally ***,the steel bar is pulled out and the PDC cutter is damaged at the penetration depth of 0.8 mm,while a good cut occurs at the penetration depth of 0.3 *** tapered PDC cutter with a relatively low cutting force is prone to be broken compared with circular PDC *** is suggested that the circular PDC cutter at the penetration depth of 0.3 mm should be used to cut RC in practical engineering.

关键词： PDC cutter RC Pipe jacking machine Linear cutting tests Damage and wear LS-DYNA

Janus Quasi‑Solid Electrolyte Membranes with Asymmetric Porous Structure for High‑Performance Lithium‑Metal Batteries

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano-Micro Letters 2024年第6期16卷 221-232页

作者： Zerui Chen wei zhao qian Liu Yifei Xu Qinghe Wang Jinmin Lin Hao Bin Wu Institute for Composites Science Innovation(InCSI)and State Key Laboratory of Silicon and Advanced Semiconductor Materials School of Materials Science and EngineeringZhejiang UniversityHangzhou 310027People’s Republic of China

Quasi-solid electrolytes(QSEs)based on nanoporous materials are promising candidates to construct high-performance Limetal batteries(LMBs).However,simultaneously boosting the ionic conductivity(σ)and lithium-ion transference number(t^(+)) of liquid electrolyte confined in porous matrix remains ***,we report a novel Janus MOFLi/MSLi QSEs with asymmetric porous structure to inherit the benefits of both mesoporous and microporous *** Janus QSE composed of mesoporous silica and microporous MOF exhibits a neat Li^(+) conductivity of 1.5.10^(–4)S cm^(−1) with t^(+) of 0.71.A partially de-solvated structure and preference distribution of Li^(+)near the Lewis base O atoms were depicted by MD ***,the nanoporous structure enabled efficient ion flux regulation,promoting the homogenous deposition of Li^(+).When incorporated in Li||Cu cells,the MOFLi/MSLi QSEs demonstrated a high Coulombic efficiency of 98.1%,surpassing that of liquid electrolytes(96.3%).Additionally,NCM 622||Li batteries equipped with MOFLi/MSLi QSEs exhibited promising rate performance and could operate stably for over 200 cycles at 1 *** results highlight the potential of Janus MOFLi/MSLi QSEs as promising candidates for next-generation LMBs.

关键词： Metal-organic frameworks Mesoporous silicas Quasi-solid electrolytes Janus structure Lithium-metal battery

Advanced Electrical Motors and Control Strategies for High-quality Servo Systems-A Comprehensive Review

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electrical Engineering 2024年第1期10卷 63-85页

作者： Ming Cheng Jiawei Zhou wei qian Bo Wang Chenchen zhao Peng Han School of Electrical Engineering Southeast UniversityNanjing 210096China ESTUN Automation Co. Ltd.Nanjing 211106China Ansys Inc.San JoseCA 95134USA

Recent technological advancements have propelled remarkable progress in servo systems,resulting in their extensive utilization across various high-end applications.A comprehensive review of high-quality servo system technologies,focusing specifically on electrical motor topologies and control strategies is *** terms of motor topology,this study outlines the mainstream servo motors used across different periods,as well as the latest theories and technologies surrounding contemporary servo *** terms of control strategies,two well-established approaches are presented:field-oriented control and direct torque ***,it discusses advanced control strategies employed in servo systems,such as model predictive control(MPC)and fault tolerance control,among others.

关键词： Servo system servo motor control strategy magnetic field modulation