检索结果-南通市图书馆

Chinese Journal of Chemistry 2024年第16期42卷 1828-1832页

作者： Lingzi Zhao Xuchao wang Qing Qiang Xingwei Zhao Feipeng Liu Shenci Lu zi-Qiang Rong Frontiers Science Center for Flexible Electronics(FSCFE) Shaanxi Institute of Flexible Electronics(SiFE)&Shaanxi Institute of Biomedical Materials and Engineering(SIBME)Northwestern Polytechnical University(NPU)127 West Youyi RoadXianShaanxi 710072China Honors College Northwestern Polytechnical University(NPU)127 West Youyi RoadXi'anShaanxi 710072China

An asymmetric isomerization/intramolecular coupling reaction of allylic alcohols to synthesize chiral dihydrocoumarins was successfully accomplished through ruthenium *** method demonstrates a wide substrate applicability,excellent tolerance for various functional groups,and good enantioselectivities(up to 90%ee).It provides a convenient pathway to produce a diverse range ofstructurallydistinct chiral dihydrocoumarins ingoodefficiency.

关键词： Ruthenium catalysis Asymmetric isomerization Tandem reaction Chiral dihydrocoumarins Enantioselectivity

Reinfection and Risk Factors of SARS-CoV-2 during an Omicron Wave 2022 in Shanghai

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Biomedical and Environmen.al Sciences 2024年第2期37卷 204-209页

作者： wang Pei Qin wang Xiao Hang wang Jian SHI Zhi Wen CHU Dong Mei wang Zhi Fei ZHANG Mu Bai LIU Wei ZHOU zi Jie XIE Wei Fen Departmen. of Gastroenterology Changzheng HospitalNaval Medical UniversityShanghai 200003China Health examination center Changzheng HospitalNaval Medical UniversityShanghai 200003China

Multiple waves of coronavirus disease 2019(COVID-19) outbreaks have affected numerous countries worldwide. The first case of SARS-CoV-2 reinfection was reported in Hong Kong in August 2020^([1]), leading to increased interest in the effectiveness of natural immunity acquired from primary infection. While data reports vary across countries, all findings indicate that prior SARS-CoV-2 infection provides substantial protection against reinfection^([2]). However, natural immunity from infection with previous non-Omicron or early Omicron sub-lineages offers lower levels of protection against Omicron reinfection, with rates below 60%^([3]) and approximately 75%[4], respectively.

关键词： immunity infection Omi

Preparation of yttrium oxide coating with enhanced thermal shock resistance on refractories used for titanium alloy melting and casting

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第6期31卷 1411-1422页

作者： Ao Chen Yan Ma Zhou-fu wang Hao Liu Xi-tang wang Sen-na Chen Chen-xin Zhang zi-yi Tang Wei-dong Fu Wei Cheng The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Xiangyang Juli High Technology Material Co. Ltd.Xiangyang 441705HubeiChina Xiangyang Public Inspection and Testing Center Xiangyang 441000HubeiChina

In order to enhance the service life of refractories for melting and casting of titanium alloy,preparation of yttrium oxide coatings on the refractories surface is an effective *** improvemen. of thermal shock stability of the coating is beneficial to its spalling resistance during the high-temperature service,and the available slurry with good performance is the *** effects of the varieties and contents of dispersant(sodium tripolyphosphate,sodium hexametaphosphate,sodium pyrophosphate,citric acid and polycarboxylate ammonium salt)and binder(aluminum dihydrogen phosphate,zirconium acetate and yttria sol)on the stability,rheological and thixotropic properties of yttrium oxide waterbased slurry were investigated,and the effects of slurry composition design on the thermal shock resistance of the coating were *** results showed that the introduction of polycarboxylate ammonium salt as dispersant significantly improved the stability of the slurry,and the varieties of the binders had significant effects on the dispersibility of the *** aluminum dihydrogen phosphate and polycarboxylate ammonium salt were used as binder and dispersant,respectively,the slurry had better stability,suitable rheological and thixotropic *** using aluminum dihydrogen phosphate as binder,the coating had good thermal shock resistance and no obvious cracks were observed for the coating after thermal shock,which was attributed to the yttrium aluminate binding phase generated in the *** effective method was provided for preparing yttrium oxide coatings with enhanced thermal shock resistance applied in the process of titanium alloy melting and casting.

关键词： Yttrium oxide-Slurry Stability Rheological property Thixotropic property-Coating Thermal shock resistance

Fabrication of dense SiBCN monolith at a lower temperature and its high-temperature performance

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 Advanced Ceramics 2024年第8期13卷 1198-1211页

作者： zi-Bo Niu Daxin Li Dechang Jia Zhihua Yang Kunpeng Lin Yan wang Paolo Colombo Ralf Riedel Yu Zhou Institute for Advanced Ceramics School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150080China Key Laboratory of Advanced Structural-Function Integrated Materials and Green Manufacturing Technology Ministry of Industry and Information TechnologyHarbin 150080China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150080China Departmen. of Industrial Engineering University of PadovaPadova 3513iItaly Departmen. of Materials Science and Engineering The Pennsylvania State UniversityUniversity Park 16802USA Institute of Materials Science Darmstadt University of TechnologyDarmstadt 64287Germany School of Materials Science and Engineering Harbin Institute of Technology(Shenzhen)Shenzhen 518055China

In this study,a crack-free pyrolysis process of partially cured precursor powder compacts was developed to prepare dense silicon boron carbonitride(SiBCN)monoliths at much lower temperatures(1300℃),thereby circumventing the challenges of sintering densification(>1800℃).Unlike the elastic fracture in over-cured precursors or the viscoelastic deformation in under-cured precursors,the partially cured precursor,exhibiting elastic-plastic deformation behavior,facilitates limited nanoscale pore formation in a dense structure,achieving a balance between crack-free pyrolysis and *** to SiBCN derived from the over-cured precursor(σ=~159 MPa,K_(IC)=1.9 MPa:m^(1/2),Vickers hardness(HV)=7.8 GPa,and E=122 GPa),the resulting SiBCN monolith exhibited significantly improved mechanical properties(σ=~304 MPa,K_(IC)=3.7 MPa-m12,HV=10.6 GPa,and E=161 GPa)and oxidation *** addition,this study investigated the high-temperature performance of SiBCN monoliths,including crystallization and oxidation,and determined the oxidation kinetics induced by pore structure healing and the different oxidation mechanisms of Si-C-N and B-C-N clusters in the amorphous *** to its unique composition and structure,the SiBCN ceramic oxide layer exhibits exceptional self-healing effects on repairing the nanoporous system in the initial stage and shows outstanding high-temperature stability during prolonged oxidation,mitigating adverse effects from bubble formation and *** to the nanoporous structure,the oxidation rate is initially controlled by gas diffusion following a linear law before transitioning to oxide layer diffusion characterized by a parabolic ***,due to different valence bond configurations,Si-C-N transforms into an amorphous SiCNO structure after phase separation,unlike the nucleation and growth of residual B-N-C.

关键词： silicon boron carbonitride(SiBCN)ceramics crack-free pyrolysis amorphous structure oxidation mechanisms kinetic law

Hydrophobic long-chain two-dimen.ional perovskite scintillators for underwater X-ray imaging

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2024年第1期43卷 175-185页

作者： Jin-Xiao Zheng zi-An Zhou Tiao Feng Hui Li Cheng-Hua Sun Nüwang Yang Tian Yong Zhao Shu-Yun Zhou Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Laboratory of Bioinspired Smart Interfacial Science and Technology of the Ministry of Education Beijing Key Laboratory of Bioinspired Energy Materials and DevicesSchool of ChemistryBeijing Advanced Innovation Center for Biomedical EngineeringBeihang UniversityBeijing 100191China Departmen. of Engineering Physics Tsinghua University and Key Laboratory of Particle and Radiation Imaging Ministry of EducationTsinghua UniversityBeijing 100084China e-mail:yangt@***

The underwater X-ray imaging technology developmen. is significant to subaqueous target reconnaissance/detection/identification, subfluvial archaeology,submerged resource exploration, etc. As the core of X-ray imaging detection, the scintillator has been plagued by inherent moisture absorption and decomposition, and strict requiremen.s for seamless packaging and ***, we designed a manganese-doped two-dimen.ional(2D) perovskite scintillator modified by hydrophobic longchain organic amine through the combination of component and doping engineering. The modified perovskites show high water repellency that can be used as an underwater X-ray scintillator. X-ray images of aquatic organisms or other objects with a high spatial resolution of10 lp·mm^(-1) at a big view field(32 mm × 32 mm) were obtained by scintillation screen. This hydrophobic perovskite scintillator based on molecular design is of great promise in underwater X-ray nondestructive testing technology developmen..

关键词： Two-dimen.ional perovskite Hydrophobic Scintillators Underwater X-ray imaging Underwater nondestructive testing technology

A low-melting-point metal doping strategy for the synthesis of small-sized intermetallic Pt_(5)Ce fuel cell catalysts

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第9期17卷 8112-8118页

作者： zi-Jun Zou Shi-Yi Yin Yao Tang Sheng-Liang Zhong Lei wang Shi-Long Xu Hai-Wei Liang College of Chemistry and Chemical Engineering Jiangxi Normal UniversityNanchang 330022China Departmen. of Chemistry University of Science and Technology of ChinaHefei 230026China School of Materials and Chemical Engineering Anhui Jianzhu UniversityHefei 230601China

Carbon-supported platinum-lanthanum(Pt-Ln)intermetallic compound(IMC)nanoparticles with high activity and robust stability have been demonstrated as promising cathode catalysts for proton-exchange membrane fuel ***,the preparation of Pt-Ln IMC catalysts needs high-temperature annealing treatmen. that inevitably causes nanoparticle sintering,resulting in significant reduction of the electrochemical surface area and mass-based ***,we prepare small-sized M-doped Pt_(5)Ce(M=Ga,Cd,and Sb)IMCs catalysts via a low-melting-point metal doping *** speculate that the doping of low-melting-point metals can facilitate the generation of vacancies in the crystal lattice through thermal activation and thus reduce the kinetic barriers for the formation of intermetallic Pt_(5)Ce *** prepared Ga-doped Pt_(5)Ce catalyst exhibits a higher electrochemical active surface area(81 m^(2)·gPt^(-1))and a larger mass activity(0.45 A·mgPt^(-1)at 0.9 V)over the undoped Pt_(5)Ce and commercial Pt/C *** the membrane electrode assembly test,the Ga-doped Pt_(5)Ce cathode delivers a power density of 0.98 W·cm^(-2)at 0.67 V,along with a voltage loss of only 27 mV at 0.8 A·cm^(-2)at the end of accelerated stability test.

关键词： P5Ce low-melting-point metal small-sized intermetallic compound catalysis fuel cells

Oxidation resistant low-alloyed Ti alloys with good ductility

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2024年第8期43卷 3921-3936页

作者： men. Li Zhang-Zhi Shi Jun-Yi Xu Fu-Zhi Dai Xiang-Min Li zi-Lin Li Lu-Ning wang Beijing Advanced Innovation Center for Materials Genome Engineering State Key Laboratory for Advance Metals and MaterialsSchool of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijingBeijing 100083China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004China

Oxidation resistance enhancemen. of pure Ti often comes at the cost of reduced ductility,which is frequently the problem through alloying with sole Al,Si,W,Mo and *** overcome the short coming of single elemen. alloying,this paper proposes a multi-elemen. low-alloying strategy to take advantage of synergistic effects and resolve the conflict between oxidation resistance and *** demonstrates that the addition of a small quantity of Ta(0.51wt%)can boost both oxidation resistance and ductility in comparison to pure ***,the combined addition of a small amount(0.54 wt%)of Ta,Nb and Si not only preserves good ductility of pure Ti,but also reduces mass gains to 14%-67%of pure Ti during 100 h oxidation at 650-850℃in *** indicates even better oxidation resistance than that obtained through the use of Ta,Nb,or Nb+Ta *** Ta+Nb+Si alloying creates an oxide layer that is less porous and more resistant to stratification and ***,a 3-μm N-rich layer can form in the Ti substrate beneath the oxide scale,in which phase transformation generates coherent Ti_(2)N with(0001)_(Ti)as the habit plane,with N atoms prefers to diffuse along■than along[0001]_(Ti).The completely transformed Ti_(2)N region or partially transformed Ti+Ti_(2)N region can effectively impede oxygen ***,the multielemen. low-alloying strategy is promising for enhancing both oxidation resistance and mechanical properties of metallic materials in the future.

关键词： Ti alloys Multi-elemen. Co-alloying Oxidation resistance Mechanical properties

Study of baryon number transport dynamics and strangeness conservation effects using Ω-hadron correlations

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第7期35卷 147-156页

作者： Wei-Jie Dong Xiao-Zhou Yu Si-Yuan Ping Xia-Tong Wu Gang wang Huan-Zhong Huang zi-Wei Lin Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Fudan UniversityShanghai 200433China Departmen. of Physics and Astronomy University of CaliforniaLos AngelesCA 90095USA Departmen. of Physics East Carolina UniversityGreenvilleNC 27858USA

In nuclear collisions at RHIC energies, an excess of Ω hyperons over ■ is observed, indicating that Ω has a net baryon number despite s and s quarks being produced in pairs. The baryon number in Ω may have been transported from the incident nuclei and/or produced in the baryon-pair production of Ω with other types of anti-hyperons such as Ξ. To investigate these two scenarios, we propose to measure the correlations between Ω and K and between Ω and anti-hyperons. We use two versions, the default and string-melting, of a multiphase transport(AMPT) model to illustrate the method for measuring the correlation and to demonstrate the general shape of the correlation. We present the Ω-hadron correlations from simulated Au+Au collisions at ■ =7.7 and 14.6 Ge V and discuss the dependence on the collision energy and on the hadronization scheme in these two AMPT versions. These correlations can be used to explore the mechanism of baryon number transport and the effects of baryon number and strangeness conservation on nuclear collisions.

关键词： Baryon number transport Strangeness conversation Correlation Gluon junction

UPLC-Q-TOF/MS-Based Serum Metabolomics Reveals Potential Anti-tumor Mechanism of Banxia Xiexin Decoction in Colorectal Cancer Mice

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Integrative Medicine 2024年第7期30卷 623-632页

作者： YUE Yin-zi LI Ming-xuan wang Xiao-hui QIN Yuan-yuan wang Ya-hui TAN Jin-hua SU Lian-lin YAN Shuai Departmen. of General Surgery Suzhou TCM Hospital Affiliated to Nanjing University of Chinese MedicineSuzhou215009China School of Pharmacy Nanjing University of Chinese MedicineNanjing210023China Departmen. of General Surgery Bayinguoleng Mongolian Autonomous Prefecture People’s HospitalXinjiang Uygur Autonomous RegionKorla841000China Departmen. of Pharmacy Suzhou TCM Hospital Affiliated to Nanjing University of Chinese MedicineSuzhou215009China Departmen. of Anorectal Surgery Suzhou TCM Hospital Affiliated to Nanjing University of Chinese MedicineSuzhou215009China

Objective To clarify the potential mechanism of Banxia Xiexin Decoction(BXD)on colorectal cancer(CRC)from the perspective of *** Forty male C57BL/6 mice were randomly divided into normal control(NC),azoxymethane/dextran sulfate sodium(AOM/DSS)model,low-dose BXD(L-BXD),high-dose BXD(H-BXD)and mesalamine(MS)groups according to a random number table,8 mice in each *** cancer model was induced by AOM/*** was administered daily at doses of 3.915(L-BXD)and 15.66 g/kg(H-BXD)by gavage for consecutive 21 days,and 100 mg/kg MS was used as positive *** the entire modeling cycle,colon length of mice was measured and quantity of colorectal tumors were *** spleen and thymus index were determined by calculating the spleen/thymus weight to body *** cytokine and changes of serum metabolites were analyzed by enzyme-linked immunosorbent assay kits and ultra performance liquid chromatography-quadrupole/time-of-flight mass spectrometry(UPLC-Q/TOF-MS),*** Notably,BXD supplemen.ation protected against weight loss,mitigated tumor formation,and diminished histologic damage in mice treated with AOM/DSS(P<0.05 or P<0.01).Moreover,BXD suppressed expression of serum inflammatory enzymes,and improved the spleen and thymus index(P<0.05).Compared with the normal group,102 kinds of differential metabolites were screened in the AOM/DSS group,including 48 potential biomarkers,involving 18 main metabolic *** 18 potential biomarkers related to CRC were identified,and the anti-CRC mechanism of BXD was closely related to D-glutamine and D-glutamate metabolism,phenylalanine,tyrosine and tryptophan biosynthesis,arginine biosynthesis,nitrogen metabolism and so *** BXD exerts partial protective effects on AOM/DSS-induced CRC by reducing inflammation,protecting organism immunity ability,and regulating amino acid metabolism.

关键词： colorectal cancer metabolomics ultra performance liquid chromatography-quadrupole/time-of-flight mass spectrometry azoxymethane dextran sulfate sodium Banxia Xiexin Decoction Chinese medicine

The SLEGS beamline of SSRF

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第7期35卷 20-30页

作者： Long-Xiang Liu Hong-Wei wang Gong-Tao Fan Hang-Hua Xu Yue Zhang zi-Rui Hao Ai-Guo Li Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai201210China

The Shanghai Laser Electron Gamma Source(SLEGS, located in BL03SSID) beamline at the Shanghai Synchrotron Radiation Facility(SSRF) is a Laser Compton Scattering(LCS) gamma source used for the investigation of nuclear structure, which is in extensive demand in fields such as nuclear astrophysics, nuclear cluster structure, polarization physics, and nuclear energy. The beamline is based on the inverse Compton scattering of 10640 nm photons on 3.5 GeV electrons and a gamma source with variable energy by changing the scattering angle from 20° to 160°. γ rays of 0.25-21.1 MeV can be extracted by the scheme consisting of the interaction chamber, coarse collimator, fine collimator, and attenuator. The maximum photon flux for 180° is approximately 10~7 photons/s at the target at 21.7 MeV, with a 3-mm-diameter beam. The beamline was equipped with four types of spectrometers for experimen.s in( γ,γ'),( γ,n),( γ,p), and( γ,α). At present, Nuclear Resonance Fluorescence(NRF) spectrometry, Flat-Efficiency neutron Detector(FED) spectrometry, neutron Time-Of-Flight(TOF) spectrometry, and Light-Charged Particle(LCP) spectrometry methods have been developed.

关键词： Shanghai Synchrotron Radiation Facility SLEGS Nuclear astrophysics Nuclear structure