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n-Heterocyclic carbene-catalyzed enantioselective(dynamic) kinetic resolutions and desymmetrizations

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Science China Chemistry 2024年第2期67卷 482-511页

作者： yi Zhang Hui Cai Xiuhai Gan Zhichao jin national Key Laboratory of Green Pesticide Key Laboratory of Green Pesticide and Agricultural BioengineeringMinistry of EducationGuizhou UniversityHuaxi DistrictGuiyang550025China

n-heterocyclic carbene-catalyzed enantioselective kinetic resolutions,dynamic kinetic resolutions,and desymmetrization reactions are systematically *** content is organized according to the activation modes involved i... 详细信息

关键词： n-heterocyclic carbene kinetic resolution dynamic kinetic resolution desymmetrization organocatalysis

Global Zero-relaxation Limit Problem of the Electro-diffusion Model Arising in Electro-Hydrodynamics

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Acta Mathematicae Applicatae Sinica 2024年第1期40卷 241-268页

作者： Ming-hua Yang Si-ming Huang jin-yi Sun Department of Mathematics Jiangxi University of Finance and EconomicsNanchang330032China School of Public Administration Guangdong University of Foreign StudiesGuangzhou510006China College of Mathematics and Statistics Northwest Normal UniversityLanzhou730070China

In this paper,we study a global zero-relaxation limit problem of the electro-diffusion model arising in electro-hydrodynamics which is the coupled Planck-nernst-Poisson and navier-Stokes *** is,the paper deals with a singular limit problem of{u^(∈)_(t)+u^(∈)·▽u^(∈)-Δu^(∈)+▽P^(∈)=Δφ^(∈)▽φ^(∈),in R^(3)×(0,∞),▽·u^(∈)=0,in R^(3)×(0,∞),n^(∈)_(t)+u^(∈)·▽n^(∈)-Δn^(∈)=-▽·(n^(∈)▽φ^(∈)),in R^(3)×(0,∞),ct+u^(∈)·▽c^(∈)-Δc^(∈)=▽·(c^(∈)▽φ^(∈)),in R^(3)×(0,∞),∈^(-1)φ^(∈)_(t)=Δφ^(∈)-n^(∈)+c^(∈),in R^(3)×(0,∞),(u^(∈),n^(∈),c^(∈),φ^(∈))|t=0=(u0,n0,c0,φ0),in R^(3) involving with a positive,large parameter^(∈).The present work show a case that(u^(∈),n^(∈),c^(∈))stabilizes to(u^(∞),n∞,c∞):=(u,n,c)uniformly with respect to the time variable as^(∈)→+∞with respect to the strong topology in a certain Fourier-Herz space.

关键词： fourier-Herz space littlewood-Paley decomposition stability limit dissipative system

Pt nanoclusters modified porous g-C_(3)n_(4)nanosheets to significantly enhance hydrogen production by photocatalytic water reforming of methanol

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Chinese Journal of Chemical Engineering 2024年第2期66卷 40-50页

作者： yi-Fei Liang jin-Rong Lu sh.ng-Kun Tian Wen-Quan Cui Li Liu Hebei Provincial Key Laboratory of Environmental Photocatalytic and Electrocatalytic Materials College of Chemical EngineeringNorth China University of Science and TechnologyTangshan 063210China

For the use of green hydrogen energy,it is crucial to have efficient photocatalytic activity for hydrogen generation by water reforming of methanol under mild *** attention has been paid to gC_(3)n_(4)as a promising photocatalyst for the generation of *** improve the separation of photogenerated charge,porous nanosheet g-C_(3)n_(4)was modified with Pt nanoclusters(Pt/g-C_(3)n_(4))through impregnation and following photo-induced *** catalyst showed excellent photocatalytic activity of water reforming of methanol fo r hydrogen production with a 17.12 mmol·g^(-1)·h^(-1)rate at room temperature,which was 311 times higher than that of the unmodified g-C_(3)n_(4).The strong interactions of Pt-n in Pt/g-C_(3)n_(4)constructed effective electron transfer channels to promote the separation of photogenerated electrons and holes *** addition,in-situ infrared spectroscopy was used to investigate the intermediates of the hydrogen production reaction,which proved that methanol and water eventually turn into H_(2)and CO_(2)via formaldehyde and *** study provides insights for understanding the photocatalytic hydrogen production in the water reforming of methanol.

关键词： Water reforming of methanol Photocatalysis g-C_(3)n_(4) Pt nanoclusters Hydrogen production

Optical Transient Source AT2021lfa:A Possible“Dirty Fireball”

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Research in Astronomy and Astrophysics 2024年第4期24卷 124-133页

作者： Xue-Mei Ye Da-Ming Wei yi-Ming Zhu Zhi-Ping jin Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China national Astronomical Observatories/nanjing Institute of Astronomical Optics&Technology Chinese Academy of SciencesNanjing 210042China CAS Key Laboratory of Astronomical Optics&Technology Nanjing Institute of Astronomical Optics&TechnologyNanjing 210042China

AT2021lfa,also known as ZTF21aayokph,was detected by the Zwicky Transient Facility on 2021 May 4,a 05:34:48 ***-up observations were conducted using a range of ground-based optical telescopes,as wel as Swift/XRT and VLA ***2021lfa is classified as an“orphan afterglow”candidate due to its rapid flux decline and its reddened color(g-r=0.17±0.14 mag).For an optical transient source without promp gamma-ray detection,one key point is to determine its burst *** we measure the burst time through fitting the initial bump feature of AT2021lfa and obtain its burst time as 2021 May 3,at 22:09:50 *** afterglowpy,we model the multi-band afterglow of AT2021lfa and find that the standard model canno reproduce the late radio observations *** that the microphysical parameters ε_(e),ε_(B)(the energy fraction given to electrons and magnetic field),andξn(the fraction of accelerated electrons)may vary with time we then model the afterglow of AT2021lfa taking into account the temporal evolution of the physical parameters ε_(e),ε^(B),and ξ_(n) and find in this case the multi-wavelength observations can be reproduced *** initial Lorentz factor of AT2021lfa can be estimated from the peak time of the early afterglow,which yields a value of about 18 suggesting that AT2021lfa should be classified as a“dirty fireball.”From the upper limit for the prompt emission energy of AT2021lfa,we obtain that the radiation efficiency is less than 0.02%,which is much smaller than that of ordinary gamma-ray bursts(GRBs).It is also interesting that the fitted values of jet angle and viewing angle are very large,θ_(c)~0.66 rad,θ_(v)~0.53 rad,which may lead to the low Lorentz factor and radiation *** compared with GRB afterglow samples,it is evident that the onset bump timescale of AT2021lfa satisfies the empirical relationships observed in GRB ***,the luminosity of AT2021lfa falls within the range of observations for GRB samples;howeve

关键词： gamma-rays:ISM methods:numerical radiation mechanisms:non-thermal

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

Extraction of Eugenol from Essential Oils by In Situ Formation of Deep Eutectic Solvents:A Green Recyclable Process

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Journal of Analysis and Testing 2024年第1期8卷 63-73页

作者： Lingqi sh.n Xiangzi jin Zhihui Zhang Yuexing yi jingyu Zhang Zuguang Li College of Chemical Engineering Zhejiang University of TechnologyHangzhou 310014China Department of Chemistry Yanbian UniversityYanji 133002China Transfar Zhilian Co. Ltd.Hangzhou 311215China

Eugenol is extensively utilized in chemical *** actual production,it is mainly separated from clove essential oils(EOs)through acid-base *** this work,a simple,rapid and effective extraction process was developed for the extraction of eugenol from EOs samples by directly forming deep eutectic solvents(DESs)without using acid-base *** proposed process is designed to dissolve EOs in n-hexane and eugenol was highly selective extracted into DESs with tetrabutylammonium chloride(TBAC).Hydrogen bonds in DESs can be broken by addition of water,resulting in a separation of the two phases,thus obtaining a hydrophobic yellowish eugenol in the upper *** quaternary ammonium salt in the lower aqueous solution can be reused after *** most determining influence factors such as the structure of quaternary ammonium salt,the mole ratio of quaternary ammonium salt to eugenol and the amount of n-hexane were *** forming conditions of DESs were studied by Box-Behnken design(BBD).Experiment was carried out under the optimal conditions and good experimental result was demonstrated by the developed process,a high extraction recovery of 92.51% and the purity was about 98.50%,which verifies the excellent performance for the proposed process.

关键词： Eugenol Deep eutectic solvent Essential oils Tetrabutylammonium chloride

Self-adaptive gas flow and phase change behaviors during hydrate exploitation by alternate injection of n_(2) and CO_(2)

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Petroleum Science 2024年第3期21卷 2120-2129页

作者： Bo-Jian Cao yi-Fei Sun Hong-nan Chen jin-Rong Zhong Ming-Long Wang Ming Wang Chang-Yu Sun Guang-jin Chen State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing102249China School of Chemistry and Chemical Engineering Changsha University of Science&TechnologyChangsha410114HunanChina

Since hydrate resources play a part of the stratigraphic framework structure in sediments,establish.ng a safe and economic method for hydrates exploitation remains the primary challenge to this *** the proposed methods,the spontaneous displacement of CH_(4) from hydrate cages by CO_(2) seems to be a perfect mechanism to address gas production and CO_(2) storage,especially in today's strong demand for carbon reduction and replacing clean *** extensive lab researches,in the past decade,injecting a mixture of CO_(2) and small molecule gas has become a key means to enhance displacement efficiency and has great potential for ***,there is a lack of in-depth research on gas flow in the reservoir,while the injected gas always passes through low-saturated hydrate areas with high permeability and then occurs gas channel in a short term,finally resulting in the decreases in gas production efficiency and produced gas ***,we explored a new injection-production mode of alternate injection of n2 and CO_(2) in order to fully coordinate the advantages of n_(2) in enhanced hydrate decomposition and CO_(2) in solid storage and heat *** alternate"taking"and"storing"processes perfectly repair the problem of the gas channel,achieving self-regulation effect of CH_(4) recovery and CO_(2) *** 3-D experimental results show that compared to the mixed gas injection,CH_(4) recovery is increased by>50%and CO_(2) storage is increased by>70%.Additionally,this alternate injection mode presented a better performance in CH_(4) concentration of produced gas and showed outstanding n_(2) utilization ***,we analyzed its self-adaptive gas flow mechanism and proposed an application model of"one injection and multiple production".We look forward to this study accelerating the application of CO_(2)-CH_(4) replacement technology.

关键词： Hydrate Replacement CH_(4)recovery CO_(2)storage Reservoir remediation

Langmuir-Schaefer Film Investigation and Density Functional Theory Band Gap Calculations of Calix[n]arene-Para-Aminobenzoic Acid for Drug nanosensor Application

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Journal of Wuhan University of Technology(Materials Science) 2024年第5期39卷 1311-1318页

作者： WOnG Yeong yi F L Supian A Radzwan M Musa n F n Abd Karim Department of Physics Sultan Idris Education UniversityTanjong Malim 35900Malaysia Department of Chemistry Sultan Idris Education UniversityTanjong Malim 35900Malaysia

Calix[n]arenes was utilized to detect PABA,the primary sunscreen *** study investigates the interaction of calix[4]arene(C4),calix[6]arene(C6),and PABA using the Langmuir method and first-principle density functional theory(DFT).Using the Langmuir-Schaefer(LS)technique,an ultrathin film composed of calix[n]arenes and their complexes with PABA was deposited on various *** on the Langmuir study,the PABA molecule was bonded to the lower rims of both C4 and C6 with the host-guest ratio of 1:*** of the LS films formed were then characterized by ultravioletvisible spectroscopy(UV-Vis),Fourier-transform infrared spectroscopy(FTIR)and carbon,hydrogen,nitrogen,sulfur elemental analyzer(CHnS).The band gap reduction obtained in the DFT study denotes the charge transfer interaction with promising reactivity between the calix[n]arenes and *** sensing of PABA by C4 and C6 is successful based on the formation of bonding between them due to the hosts’effective trapping *** outcomes of this study could be applied to drug delivery systems for future pharmaceutical and medical applications.

关键词： calix[n]arenes band gap density functional theory Langmuir-Schaefer PABA sensor

Electroacupuncture at Sensitized Acupoints Relieves Somatic Referred Pain in Colitis Rats by Inhibiting Sympathetic-Sensory Coupling to Interferewith 5-HT Signaling Pathway

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Chinese Journal of Integrative Medicine 2024年第2期30卷 152-162页

作者： YAnG ying QU jin-yu GUO Hua ZHOU Hai-ying RUAn Xia PEnG ying-chun sh.n Xue-fang XIOnG jin WAnG yi-li School of Clinical Medicine Chengdu Medical CollegeChengdu(610500)China Department of Rehabilitation Medicine the First Affliated Hospital of Chengdu Medical CollegeChengdu(610500)China Department of Rehabilitation Medicine West China HospitalSichuan University/West China School of NursingSichuan UniversityChengdu(610041)China Department of neurology the First Affiliated Hospital of Chengdu Medical CollegeChengdu(610500)China

Objective:To investigate whether electroacupuncture(EA) at sensitized acupoints could reduce sympathetic-sensory coupling(SSC) and neurogenic inflammatory response by interfering with 5-hydroxytryptamine(5-HT)ergic neural pathways to relieve colitis and somatic referred pain,and explore the underlying ***:Rats were treated with 5% dextran sodium sulfate(DSS) solution for 7 days to establish a colitis *** rats were randomly divided into the control and model groups according to a random number table(n=6).According to the Research on Rat Acupoint Atlas",sensitized acupoints and non-sensitized acupoints were *** were randomly divided into the control,model,Zusanli-EA(ST 36),Dachangshu-EA(BL 25),and Xinshu(BL 15) groups(n=6),as well as the control,model,EA,and EA+GR113808(a 5-HT inhibitor)groups(n=6).The rats in the control group received no *** was administered on 2 days after modeling using the stimulation pavameters:1 mA,2 Hz,for 30 min,with sparse and dense waves,for 14 consecutive ***113808 was injected into the tail vein at 5 mg/kg before EA for 10 min for 7 consecutive *** sensitivity was assessed with von Frey *** weight and disease activity index(DAI) scores of rats were *** and eosin staining was performed to observe colon *** was analyzed by immunofluorescence *** staining was performed to detect 5-HT and substance P(SP) *** calcitonin gene-related peptide(CGRP) in skin tissue and tyrosine hydroxylase(TH) protein levels in DRG were detected by Western *** levels of hyaluronic acid(HA),bradykinin(BK),prostaglandin I2(PGI2) in skin tissue,5-HT,tryptophan hydroxylase 1(TPH1),serotonin transporters(SERT),5-HT 3 receptor(5-HT3R),and 5-HT 4 receptor(5-HT4R) in colon tissue were measured by enzyme-linked immunosorbent assay(ELISA).Results:BL 25 and ST 36 acupoints were determined as sensitized acupoints,and BL 1

关键词： electroacupuncture sensitized acupoints sympathetic-sensory coupling 5-hydroxytryptamine neurogenic inflammation somaticreferredpain