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Enantioselective Synthesis of cis-2,6-Disubstituted-4-methylene Tetrahy-dropyrans via Chromium Catalysis

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Chinese Journal of Chemistry 2020年第12期38卷 1642-1646页

作者： Jing Bai Bin Chen Guozhu Zhang State Key Laboratory of organometallic Chemistry Center for Excellence in Molecular Synthesis Shanghailnstitute of Organic ChemistryUniversty of Chinese Academy of SciencesChinese Academy of Sciences345 Lingling RoodShanghai 200032China

of main observation and conclusion Enantioenriched 2,6-disubstituted 4-methylene tetrahydropyrans have been obtained via a two-step sequence consisting of a highly enantioselective chromium-catalyzed carbonyl 2-(trimethylsilyl methyl)allylation and Prins cyclization.Commercially available(2-(chloromethyl)allyl)trimethylsilane serves as the bifunctional linchpin to combine two aldehydes to assemble the 2,6-disubstituted pyrans.A variety of functional groups are compatible under the mild reaction conditions.The synthetic utility of this methodology was demonstrated by the asymmetric synthesis of 16 examples of homoallylic alcohol and 8 examples of 2,6-disubstituted 4-methylene tetrahydropyrans,including an advanced intermediate which could be transformed to natural product centrolobine via a known procedure.

关键词： substituted methylene allyl

Gelfand-Kirillov Dimension and Reducibility of Scalar Generalized Verma Modules for Classical Lie Algebras

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Acta Mathematica Sinica,English Series 2024年第3期40卷 658-706页

作者： Zhan Qiang bai jing JIANG School of Mathematical Sciences Soochow UniversitySuzhou 215006P.R.China E-mail:zqbai@*** jjsd6514@***

Let g be a classical complex simple Lie algebra and q be a parabolic subalgebra.Let M be a generalized Verma module induced from a one dimensional representation of q.Such M is called a scalar generalized Verma module.In this paper,we will determine the reducibility of scalar generalized Verma modules associated to maximal parabolic subalgebras by computing explicitly the Gelfand-Kirillov dimension of the corresponding highest weight modules.

关键词： Generalized Verma module Gelfand-Kirillov dimension Young tableau

Global Stability of a Time-delayed Malaria Model with Standard Incidence Rate

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Acta Mathematicae Applicatae Sinica 2023年第2期39卷 211-221页

作者： Song-bai GUO Min HE jing-an CUI School of Science Beijing University of Civil Engineering and ArchitectureBeijing 102616China Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China

A four-dimensional delay differential equations(DDEs)model of malaria with standard incidence rate is proposed.By utilizing the limiting system of the model and Lyapunov direct method,the global stability of equilibria of the model is obtained with respect to the basic reproduction number R_(0).Specifically,it shows that the disease-free equilibrium E^(0)is globally asymptotically stable(GAS)for R_(0)1.Especially,to obtain the global stability of the equilibrium E^(*)for R_(0)>1,the weak persistence of the model is proved by some analysis techniques.

关键词： malaria model delay differential equations Lyapunov functional weak persistence global stability

Development and Analysis of a New Cylindrical Lithium-Ion Battery Thermal Management System

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Chinese Journal of Mechanical Engineering 2022年第4期35卷 298-312页

作者： Yasong Sun Ruihuai bai jing Ma School of Power and Energy Northwestern Polytechnical UniversityXi’an 710072China Center of Computational Physics and Energy Science Yangtze River Delta Research Institute of NPUNorthwestern Polytechnical UniversityTaicang 215400China School of Automobile Chang’an UniversityXi’an 710064China

With the development of modern technology and economy,environmental protection and sustainable development have become the focus of global attention.The promotion and development of electric vehicles(EVs)have bright prospects.However,many challenges need to be faced seriously.Under diferent operating conditions,various safety problems of electric vehicles emerge one after another,especially the hidden danger of battery overheating which threatens the performance of electric vehicles.This paper aims to design and optimize a new indirect liquid cooling system for cylindrical lithium-ion batteries.Various design schemes for diferent cooling channel structures and cooling liquid inlet directions are proposed,and the corresponding solid-fuid coupling model is established.COMSOL Multiphysics simulation software is adopted to simulate and analyze the cooling systems.An approximate model is constructed using the Kriging method,which is considered to optimize the battery cooling system and improve the optimization results.Sensitivity parameter analysis and the optimization design of system structure are performed through a set of infuencing factors in the battery thermal management.The results indicate that the method used in this paper can efectively reduce the maximum core temperature and balance the temperature diferences of the battery pack.Compared with the original design,the optimized design,which is based on the non-dominated sorting genetic algorithm(NSGA-II),has an excellent ability in the optimized thermal management system to dissipate thermal energy and keep the overall cooling uniformity of the battery and thermal management system.Furthermore,the optimized system can also prevent thermal runaway propagation under thermal abuse conditions.In summary,this research can provide some practical suggestions and ideas for the engineering and production applications and structural optimization design carried by electric vehicles.

关键词： Cooling system Electric vehicle Kriging approximation Numerical simulation

Selection of tree species by principal component analysis for abandoned farmland in southeastern Horqin Sandy Land,China

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Journal of Forestry Research 2022年第2期33卷 475-486页

作者： Peng Meng jing Liu Xuefeng bai Qingdao Agricultural University Qingdao 266109People’s Republic of China Liaoning Province Sand-Fixation and Afforestation Research Institute Fuxin 123000People’s Republic of China

With changes in global climate and land use,the area of desertified farmland in southeastern Horqin Sandy Land(HSL)has increased in recent years,and farmlands are being abandoned.These abandoned farmlands(AFs)nega-tively impact the local ecology.Therefore,the aim of the present study was to select suitable trees and shrubs for those AFs to prevent and control the desertification tendency.In this study,three AFs were fenced for 2 years,then 37 arbor and shrub species or varieties of 21 families were planted in the fenced AFs and grown for 10 years.The ecological adaptability of the species was evaluated and ranked using a principal component analysis.The results showed that the biodiversity of the AFs significantly improved after 2 years of fencing;the Shannon-Wiener index and species rich-ness of perennial grasses and forbs were 1.45 and 3.6 times higher,respectively,than for the unfenced AF.Among all species planted in fenced AFs,nine tree species had posi-tive comprehensive F(CF)values;Pinus sylvestris(Russian Shira steppe provenance),Populus alba‘Berolinensis’and Gleditsia triacanthos had CF greater than 1,and the first(PC1),second(PC2)and third(PC3)principal component values(F_(1),F_(2),F_(3))were all positive.Among the shrubs,only Lespedeza bicolor and Rosa xanthina f.normalis had CF greater than 0.All these results suggest that fencing improves biodiversity and that planting trees and shrubs that have higher CF values on the basis of fencing is an effective way to green and beautify AFs in HSL.

关键词： Horqin Sandy Land Fenced abandoned farmland Principal component analysis Tree species selection

Photoelectrocatalytic generation of H_(2)and S from toxic H2S by using a novel BiOI/WO_(3)nanoflake array photoanode

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Frontiers in Energy 2021年第3期15卷 744-751页

作者： Jing Bai Bo ZHANG Jinhua LI Baoxue ZHOU School of Environmental Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200090China Key Laboratory of Thin Film and Microfabrication Technology Shanghai Jiao Tong UniversityShanghai 200240China

In this paper,a photoelectrocatalytic(PEC)recovery of toxic H_(2)S into H_(2)and S system was proposed using a novel bismuth oxyiodide(BiOI)/tungsten trioxide(WO_(3))nano-flake arrays(NFA)photoanode.The BiOI/WO_(3)NFA with a vertically aligned nanostructure were uniformly prepared on the conductive substrate via transformation of tungstate following an impregnating hydroxylation of BiI3.Compared to pure WO_(3)NFA,the BiOI/WO_(3)NFA promotes a significant increase of photocurrent by 200%.Owing to the excellent stability and photoactivity of the BiOI/WO_(3)NFA photoanode and I-/I-3 catalytic system,the PEC system toward splitting of H_(2)S totally converted S_(2)-into S without any polysulfide(Sn-x)under solar-light irradiation.Moreover,H_(2)was simultaneously generated at a rate of about 0.867 mL/(h·cm).The proposed PEC H_(2)S splitting system provides an efficient and sustainable route to recover H_(2)and S.

关键词： bismuth oxyiodide(BiOI)/tungsten trioxide(WO_(3))nano-flake arrays(NFA) photoelectrocatalytic(PEC) H_(2)S splitting H_(2) S

Dopaminergic modulation of synaptic plasticity in rat prefrontal neurons

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Neuroscience Bulletin 2015年第2期31卷 183-190页

作者： Satoru Otani Jing Bai Kevin Blot Center for Medical Education Faculty of Health Sciences Ryotokuji University Chinese Medicine Research Laboratory Juntendo University Medical School Pathophysiology Department University of Paris 6

The prefrontal cortex （PFC） is thought to store the traces for a type of long-term memory - the memory that determines the temporal structure of behavior often termed a ＂rule＂ or ＂strategy＂. Long-term synaptic plasticity might serve as an underlying cellular mechanism for this type of memory. We therefore studied the induction of synaptic plasticity in rat PFC neurons, maintained in vitro, with special emphasis on the functionally important neuromodulator dopamine. First, the induction of long-term potentiation （LTP） was facilitated in the presence of tonic/background dopamine in the bath, and the dose-dependency of this background dopamine followed an ＂inverted-U＂ function, where too high or too low dopamine levels could not facilitate LTP. Second, the induction of long-term depression （LTD） by low-frequency stimuli appeared to be independent of background dopamine, but required endogenous, phasically-released dopamine during the stimuli. Blockade of dopamine receptors during the stimuli and exaggeration of the effect of this endogenouslyreleased dopamine by inhibition of dopamine transporter activity both blocked LTD. Thus, LTD induction also followed an inverted-U function in its dopamine-dependency. We conclude that PFC synaptic plasticity is powerfully modulated by dopamine through inverted-U-shaped dose-dependency.

关键词： prefrontal cortex synaptic plasticity long-term memory

Global Stability of a Mumps Transmission Model with Quarantine Measure

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Acta Mathematicae Applicatae Sinica 2021年第4期37卷 665-672页

作者： Yu-zhen bai Xiao-jing WANG Song-bai GUO School of Science Beijing University of Civil Engineering and ArchitectureBeijing102616China Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing100190China

In this paper,a model of mumps transmission with quarantine measure is proposed and then the control reproduction number Rc of the model is obtained.This model admits a unique endemic equilibrium P*if and only if Rc>1,while the disease-free equilibrium P0 always exists.By using the technique of constructing Lyapunov functions and the generalized Lyapunov-LaSalle theorem,we first show that the equilibrium P0 is globally asymptotically stable(GAS)if Rc≤1;second,we prove that the equilibrium P*is GAS if Rc>1.Our results reveal that mumps can be eliminated from the community for Rc≤1 and it will be persistent for Rc>1,and quarantine measure can also effectively control the mumps transmission.

关键词： mumps transmission model control reproduction number quarantine measure global stability

Recovery of Cu(Ⅱ) from aqueous solution by induced crystallization in a long-term operation

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Journal of Environmental Sciences 2018年第7期30卷 183-191页

作者： Zhimou Wei Ya Xiong Jian Chen Jing Bai jing Wu Jiane Zuo Kaijun Wang School of Environment Tsinghua University Beijing 100084 China Department of Environmental Science and Engineering China University of Geosciences Beijing 100083 China Chinese Academy for Environmental Planning Beijing 100012 China

The feasibility of copper recovery by induced crystallization in a long period（174 days） was investigated in a seeded fluidized bed reactor（FBR）. The process was divided into 3 periods according to different influent conditions, and the period Ⅲ was separated into Ⅲ-a and Ⅲb due to the adjustment of the molar ratio of CO3^2- concentration to copper concentration（[CT]/[Cu^2＋]）. The removal efficiency could exceed 95% and the average effluent copper concentration decreased to 3.0 mg/L. The mean particle size of seed grains with copper crystals coating on, raised to 0.36 mm from initial 0.18 mm. During period Ⅲ-a, the supersaturation exceeded 2.88 × 104, the removal efficiency decreased to 60%–80% and the particle size dropped to 0.30 mm, due to the generation of fines by homogeneous crystallization and seeds breaking. And the morphology of the crystals on the seed grains changed from rod-like to spherical which lead to the particle size decreasing. In period Ⅲ-b,the supersaturation was modified by adjusting the molar ratio of [CT]/[Cu^2＋] to 1.2 from 2.The efficiency was back to 95% and the mean particle size grew to 0.36 mm at the end of Ⅲb, the crystals coating on the seeds turned back to rod-like products of good stability. This study illustrated that the copper salt crystal could keep on growing on the seed grains for over 150 days, the feasibility and controllability of copper recovery by induced crystallization process in FBR were satisfactory, even under the dramatic changes in influent conditions.

关键词： Copper removal Induced crystallization Fluidized bed reactor Supersaturation Long-term operation