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Integrated multi-scale approach combining global homogenization and local refinement for multi-field analysis of high-temperature superconducting composite magnets

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Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 747-762页

作者： Hanxiao GUO Peifeng GAO Xingzhe WANG Key Laboratory of Mechanics on Western Disaster and Environment of Ministry of Education Key Laboratory of Special Function Materials and Structure Design of Ministry of EducationCollege of Civil Engineering and MechanicsLanzhou UniversityLanzhou 730000China

Second-generation high-temperature superconducting(HTS)conductors,specifically rare earth-barium-copper-oxide(REBCO)coated conductor(CC)tapes,are promising candidates for high-energy and high-field superconducting *** respect to epoxy-impregnated REBCO composite magnets that comprise multilayer components,the thermomechanical characteristics of each component differ considerably under extremely low temperatures and strong electromagnetic *** numerical models include homogenized orthotropic models,which simplify overall field calculation but miss detailed multi-physics aspects,and full refinement(FR)ones that are thorough but computationally ***,we propose an extended multi-scale approach for analyzing the multi-field characteristics of an epoxy-impregnated composite magnet assembled by HTS pancake *** approach combines a global homogenization(GH)scheme based on the homogenized electromagnetic T-A model,a method for solving Maxwell's equations for superconducting materials based on the current vector potential T and the magnetic field vector potential A,and a homogenized orthotropic thermoelastic model to assess the electromagnetic and thermoelastic properties at the macroscopic *** then identify“dangerous regions”at the macroscopic scale and obtain finer details using a local refinement(LR)scheme to capture the responses of each component material in the HTS composite tapes at the mesoscopic *** results of the present GH-LR multi-scale approach agree well with those of the FR scheme and the experimental data in the literature,indicating that the present approach is accurate and *** proposed GH-LR multi-scale approach can serve as a valuable tool for evaluating the risk of failure in large-scale HTS composite magnets.

关键词： epoxy-impregnated high-temperature superconducting(HTS)magnet multi-scale method global homogenization(GH) local refinement(LR) multi-field analysis

C_(Ar)-Br bond cleavage via cooperative EnT/NHC catalysis: mild access to indolines

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Science China Chemistry 2024年第3期67卷 922-927页

作者： Yi-Xiong Dong Cao-Bo Li Ming-Lei Jin Zhong-Hua Gao Song Ye Beijing National Laboratory for molecular Sciences CAS Key Laboratory of Molecular Recognition and FunctionCAS Research/Education Center for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

The cooperative visible-light mediated and NHC-catalyzed dearomative arylation-acylation of N-(2-bromobenzoyl)indoles with aldehydes was developed, affording the corresponding highly functionalized polycyclic indolines in moderate to good yields with exclusive diastereoselectivities. Mechanism investigations support the activation of CAr-Br bond via visible-light mediated energy transfer(EnT) and the following single-electron-transfer(SET) with Breslow intermediate under NHC catalysis to give key aryl radical and ketyl radical. This protocol demonstrates the cleavage of CAr-Br bond under mild cooperative EnT/NHC catalysis.

关键词： energy transfer N-heterocyclic carbenes photocatalysis aryl radicals indolines

An unprecedented synthesis of axially chiral biaryls by rearrangement and aromatization of carbocations with central-to-axial conversion of chirality

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Science China Chemistry 2024年第9期67卷 2998-3003页

作者： Qi Liu Xue-Dong Li Liang Cheng Li Liu Beijing National Laboratory for molecular Sciences(BNLMS) CAS Key Laboratory of Molecular Recognition and FunctionCAS Research/Education Center for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

The central-to-axial chirality conversion represents a fascinating class of chemical processes consisting of the destruction of stereogenic centers and the simultaneous installation of axial chiral elements,which provides efficient methods for the preparation of axially chiral ***,developing catalytic asymmetric approaches for constructing these central chirality precursors and the efficient central-to-axial chirality conversion remains a challenge due to the requirement of aromatization or elimination *** this work,we have developed an unprecedented enantioselective intramolecular FriedelCrafts alkylation with unactivated-ketone carbonyls from which a chiral tertiary alcohol was generated with high efficiency and excellent *** addition,the central-to-axial chirality conversion strategy has been successfully applied to the synthesis of enantioenriched biaryls via a less-explored carbocation-initiated rearrangement and aromatization under the promotion of Lewis *** methodology provided a straightforward and sustainable access to a broad range of biaryl-2-carboxylic acid and in excellent yields(up to 92%)and excellent central-to-axial chirality conversion(up to 99%conversion percentage).This work could be a great model for developing new methods for synthesizing axially chiral biaryls and a general protocol for the rearrangement and aromatization of carbocations for further functionalization.

关键词： br?nsted acid catalysis desymmetrization phosphoric acid axially chiral biaryls central-to-axial conversion

Ultracycles consisting of macrocycles

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Chinese Chemical Letters 2024年第5期35卷 183-188页

作者： Wen-Hui Mi Teng-Yu Huang Yu-Fei Ao Xu-Dong Wang Qi-Qiang Wang De-Xian Wang Beijing National Laboratory for molecular Sciences CAS Key Laboratory of Molecular Recognition and FunctionInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Presented here is a one-pot strategy starting from rationally designed macrocyclic precursors for the diverse construction of sophisticated *** type and amount of the base were found to significantly influence the macrocyclization *** use of 4.0 *** resulted in ultracycles of both types A and B while the presence of CsF larger than 6.0 *** only type B *** of anion template increased the total yields and affected the distribution of the *** ultracycles can accommodate large organic dicarboxylates anions via multiple anion-πand hydrogen bonds,and show selectivity to the size-matched heptanedioate(C7^(2−)).Based on all possible species and relevant equilibrium constants as well as material and charge balances,a numerical iterative algorithm was developed and applied to fit the association constants of B2H with dicarboxylates from glutarate(C5^(2−))to octanedioate(C8^(2−)),which gave association constants up to 10^(3) L/mol.

关键词： Ultracycles Diversity-oriented synthesis Anion recognition Anion-πinteraction

Asymmetric Partial Hydrosilylation of 2,2-Difluoro-1,3-diketones with Chiral Frustrated Lewis Pairs

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Chinese Journal of Chemistry 2024年第8期42卷 853-857页

作者： Ting Liu Xiangqing Feng Haifeng Du Beijing National Laboratory for molecular Sciences CAS Key Laboratory of Molecular Recognition and FunctionInstitute of ChemistryChinese Academy of SciencesBeijing100190 China University of Chinese Academy of Sciences Beijing100049 China

Comprehensive Summary,The asymmetric partial reduction of 1,3-diketones stands as a straightforward pathway to access optically active β-hydroxyketones. In this paper, an asymmetric Piers-type hydrosilylation of 2,2-difluoro-1,3-diketones was successfully realized by using a frustrated Lewis pair of chiral borane and tricyclohexylphosphine as a catalyst, delivering a variety of α,α-difluoro-β-hydroxyketones in high yields with up to 99% ee. Significantly, no over-reduced diol products were observed even with an excess amount of silanes. The product can be conveniently converted to α,α-difluoro-β-hydroxyester or 1,3-anti-diol via an oxidation with m-CPBA or a reduction with DIBAL-H without obvious loss of ee.

关键词： Asymmetric catalysis Hydrosilylation Ketones Frustrated Lewis pairs Chiral boranes

Asymmetric Hydrogenation of Phenanthridines with Chiral Boranes

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Chinese Journal of Chemistry 2024年第6期42卷 631-635页

作者： Guangyu Cui Xiangqing Feng Haifeng Du Beijing National Laboratory for molecular Sciences CAS Key Laboratory of Molecular Recognition and FunctionInstitute of ChemistryChinese Academy of SciencesBeijing100190 China University of Chinese Academy of Sciences Beijing100049 China

The asymmetric hydrogenation of N-heteroarenes provides an efficient method for the synthesis of optically active cyclic secondary *** this paper,we described an asymmetric hydrogenation of phenanthridines using a chiral mono-alkene-derived borane.A variety of dihydrophenanthridines were furnished in high yields with up to 93%*** current catalytic system was very sensitive for the steric hindrance of *** substituents at one phenyl group of phenanthridines were required to obtain the high *** large substituents on the carbon of the C=N bonds would diminish the reactivity sharply.

关键词： Asymmetric catalysis Hydrogenation Nitrogen heterocycles Phenanthridines Frustrated Lewis pairs Chiral boranes

Atorvastatin, etanercept and the nephrogenic cardiac sympathetic remodeling in chronic renal failure rats

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Journal of Geriatric Cardiology 2024年第4期21卷 443-457页

作者： Jing-Yue XU Zheng-Kai XUE Ya-Ru ZHANG Xing LIU Xue ZHANG Xi YANG Tong LIU Kang-Yin CHEN Tianjin Key Laboratory of Ionic-molecular function of Cardiovascular Disease Department of CardiologyTianjin Institute of Cardiologythe Second Hospital of Tianjin Medical UniversityTianjinChina

BACKGROUND Chronic renal failure(CRF) patients are predisposed to arrhythmias, while the detailed mechanisms are unclear. We hypothesized the chronic inflammatory state of CRF patients may lead to cardiac sympathetic remodeling, increasing the incidence of ventricular arrhythmia(VA) and sudden cardiac death. And explored the role of atorvastatin and etanercept in this *** A total of 48 rats were randomly divided into sham operation group(Sham group), CRF group, CRF + atorvastatin group(CRF + statin group), and CRF + etanercept group(CRF + rhTNFR-Fcgroup). Sympathetic nerve remodeling was assessed by immunofluorescence of growth-associated protein 43(GAP-43) and tyrosine hydroxylase positive area fraction. Electrophysiological testing was performed to assess the incidence of VA by assessing the ventricular effective refractory period and ventricular fibrillation threshold. The levels of tumor necrosis factor-alpha(TNF-α) and interleukin-1beta were determined by Western blotting and enzyme-linked immunosorbent *** Echocardiogram showed that compared with the Sham group, left ventricular end-systolic diameter and ventricular weight/body weight ratio were significantly higher in the CRF group. Hematoxylin-eosin and Masson staining indicated that myocardial fibers were broken, disordered, and fibrotic in the CRF group. Western blotting, enzyme-linked immunosorbent assay,immunofluorescence and electrophysiological examination suggested that compared with the Sham group, GAP-43 and TNF-α proteins were significantly upregulated, GAP-43 and tyrosine hydroxylase positive nerve fiber area was increased, and ventricular fibrillation threshold was significantly decreased in the CRF group. The above effects were inhibited in the CRF + statin group and the CRF + *** In CRF rats, TNF-α was upregulated, cardiac sympathetic remodeling was more severe, and the nephrogenic cardiac sympathetic remodeling existed. Atorvastatin and etanercept c

关键词： remodeling cardiac inhibited

Axial enantiomers with donor-regulated TADF feature for multicolor circularly polarized electroluminescence

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Science China Chemistry 2024年第6期67卷 2039-2045页

作者： Chen-Hao Guo Wen-Long Zhao Ke-Ke Tan Wei-Chen Guo Liheng Feng Chuan-Feng Chen Meng Li School of Chemistry and Chemical Engineering Shanxi UniversityTaiyuan030006China Beijing National Laboratory for molecular Sciences CAS Key Laboratory of Molecular Recognition and FunctionInstitute of ChemistryChinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China

This study optimized the TADF feature of axial chiral enantiomers through precise donor engineering,and multicolor CP-TADFwas achieved in the axial chiral *** pairs of axial enantiomers with donor-regulated TADF feature,namely(R/S)-TPCBD,(R/S)-DPCBD,and(R/S)-DPACBD,were synthesized by introducing carbazole donors with different substituents onto biphenyl cyanide *** the electron-donating ability of donors increases,the emission of these axial enantiomers ranges from 455,476 to 552 nm,their singlet-triplet energy gaps(ΔE_(ST))gradually decrease from 0.30,0.22 to 0.02 e V,accompanied by an increasement in the transition rate(k_(RISC))of RISC process,and the k_(RISC)of DPACBD could reach up to 7.16×10^(5)s^(-1).These axial enantiomers also exhibit mirror-image CD and circularly polarized luminescence(CPL)***,OLEDs based on TPCBD,DPCBD,and DPACBD as emitter were then fabricated,which displayed blue,green,and orange electroluminescence with EQE_(max)of 13.0%,16.4%,and 25.0%,*** results also exhibited a phenomenon of device efficiency increasing with the enhancement of donor ***,the CP-OLEDs using(R/S)-TPCBD,(R/S)-DPCBD and(R/S)-DPACBD as emitters displayed intense CPEL signals with g_(EL)values of 3.4×10^(-3)/-4.1×10^(-3),3.2×10^(-3)/-3.1×10^(-3)and2.3×10^(-3)/-2.1×10^(-3),*** convenient molecular engineering of donor regulation in the same molecular skeleton,CP-TADF materials with multicolor CPEL and improved device performance could be conveniently achieved.

关键词： axial chirality thermally activated delayed fluorescence circularly polarized luminescence electroluminescence organic light-emitting diodes

Transcatheter aortic valve replacement:A journey of two decades and beyond

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Chinese Medical Journal 2024年第9期137卷 1012-1015页

作者： Tianyuan Xiong Mao Chen Department of Cardiology West China HospitalSichuan UniversityChengduSichuan 610041China Laboratory of Cardiac structure and function Institute of Cardiovascular DiseasesWest China HospitalSichuan UniversityChengduSichuan 610041China

The number of patients with calcic aortic stenosis(AS)is 9.4 million according to 2019 Global Disease Burden estimates,which will continue to increase as the population ages.[1]For the treatment of symptomatic severe AS,transcatheter aortic valve replacement(TAVR)has evolved to be a well-established option across all risk spectra,with a rapid growth of procedures *** rise of TAVR initiates the revolution of the management of valvular heart diseases,from patient surveillance,the staging of disease,the use of multimodality imaging,the concept of the Heart Team,new designs and iterations of devices to technical innovations and the discovery of unmet clinical *** a consequence of the global adoption of TAVR,geographical differences in the epidemiology of AS and patient characteristics have also been further identi*** examination of the changing patient population,current applications and breakthroughs,and remaining challenges are crucial for the future of this ***,we discuss the temporal utilization of TAVR,the accumulation of evidence and progress of devices,the selection of patients,and some ongoing topics concerning the improvement of TAVR.

关键词： epidemiology breakthrough beyond