检索结果-南通市图书馆

Friedmann Cosmology with Bulk Viscosity:A Concrete Model for Dark Energy

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2009年第8期52卷 377-382页

作者： meng xin-he D0U Xu Department of Physics Nankai University Tianjin 300071 China Kavli Institute for Theoretical Physics China at the Chinese Academy of Sciences （KITPC-CAS） Beijing 100190 China

The universe content is considered as a non-perfect fluid with bulk viscosity and can be described by a general equation of state （endowed some deviation from the conventionally assumed cosmic perfect fluid model）. An explicitly bulk viscosity dark energy model is proposed to confront consistently with the current observational data sets by statistical analysis and is shown consistent with （not deviated away much from） the concordant A Cold Dark Matter （CDM） model by comparing the decelerating parameter. Also we compare our relatively simple viscosity dark energy model with a more complicated one by contrast with the concordant ACDM model and find our model improves for the viscosity dark energy model building. Finally we discuss the perspectives of dark energy probes for the coming years with observations.

关键词： dark energy cosmology bulk viscosity unification of dark matter and dark energy

Friedmann Cosmology with a Generalized Equation of State and Bulk Viscosity

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2007年第2期47卷 379-384页

作者： meng xin-he REN Jie HU Ming-Guang Department of Physics Nankai University Tianjin 300071 China

The universe content is considered as a non-perfect fluid with bulk viscosity and is described by a more general equation of state （endowed some deviation from the conventionally assumed cosmic perfect fluid model）. We assume the bulk viscosityis a linear combination of two terms： one is constant, and the other is proportional to the scalar expansion 0 = 3a/a. The equation of state is described as p = （γ - 1）p ＋ po, where po is a parameter. In this framework we demonstrate that this model can be used to explain the dark energy dominated universe, and different proper choices of the parameters may lead to three kinds of fates of the cosmological evolution： no future singularity, big rip, or Type-Ⅲ singularity as presented in IS. Nojiri, S.D. Odintsov, and S. Tsujikawa, Phys. Rev. D 71 （2005） 063004].

关键词： Friedmann cosmology equation of state bulk viscosity dark energy

Conservative Currents of Boundary Charges in AdS2+1 Gravity

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2001年第7期36卷 33-36页

作者： FENG Sze-Shiang WANG Bin meng xin-he CCAST (World Laboratory) P.O. Box 8730 Beijing 100080 China Department of Astronomy and Applied Physics University of Science and Technology of China Hefei 230026 China Physics Department Shanghai Normal University Shanghai 200234 China Theoretical Physics Division Department of Physics Nankai University Tianjin 300071 China

The boundary charge which constitutes the Virasoro algebra in (2-+ 1)-dirnensional anti-de Sitter gravity is derived by Noether theorem and diffeomorphic invariance. It shows that the boundary charge under discussion recently exhausts all the available independent nontrivial charges. Therefore, for any specific spacetime, the state counting via the central charge of the Virasoro algebra is exact.

关键词： boundary charge, diffeomorphic invariance

Research progress of CO_(2)oxidative dehydrogenation of propane to propylene over Cr-free metal catalysts

维普期刊数据库评论

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 2022年第7期41卷 2129-2152页

作者： Zhong-Yu Wang Zhen-Hong he Long-Yao Li Shao-Yan Yang meng-xin he Yong-Chang Sun Kuan Wang Jian-Gang Chen Zhao-Tie Liu Shaanxi Key Laboratory of Chemical Additives for Industry College of Chemistry and Chemical EngineeringShaanxi University of Science and TechnologyXi’an 710021China School of Chemistry and Chemical Engineering Shaanxi Normal UniversityXi’an 710119China

CO_(2)-assisted oxidative dehydrogenation of propane(CO_(2)-ODHP)is an attractive strategy to offset the demand gap of propylene due to its potentiality of reducing CO_(2)emissions,especially under the demands of peaking CO_(2)emissions and carbon *** introduction of CO_(2)as a soft oxidant into the reaction not only averts the over-oxidation of products,but also maintains the high oxidation state of the redox-active ***,the presence of CO_(2)increases the conversion of propane by coupling the dehydrogenation of propane(DHP)with the reverse water gas reaction(RWGS)and inhibits the coking formation to prolong the lifetime of catalysts via the reverse Boudouard *** effective catalyst should selectively activate the C–H bond but suppress the C–C ***,to prepare such a catalyst remains ***-based catalysts are always applied in industrial application of DHP;however,their toxic properties are harmful to the *** this aspect,exploring environment-friendly and sustainable catalytic systems with Cr-free is an important *** this review,we outline the development of the CO_(2)-ODHP especially in the last ten years,including the structural information,catalytic performances,and mechanisms of chromium-free metal-based catalyst systems,and the role of CO_(2)in the *** also present perspectives for future progress in the CO_(2)-ODHP.

关键词： Propane Dehydrogenation Propylene CO_(2) Chromium-free metals Catalytic performance

Network pharmacology analysis combined with experimental verification of the molecular mechanism of Xihuang pill in treating liver cancer

在线全文

学校读者我要写书评

暂无评论

Traditional Medicine Research 2023年第6期8卷 24-32页

作者： meng-xin he Ayesha T.Tahir Saba Waris Wen-Bo Cheng Jun Kang School of Life Sciences Tianjin UniversityTianjin 300072China Department of Biosciences COMSATS University IslamabadIslamabad 45550Pakistan Department of Gynacology Allama Iqbal Medical CollegeLahore 54000Pakistan Tianjin Key Laboratory of Medical Mass Spectrometry for Accurate Diagnosis Tianjin 300399China

Background:Xihuang pill is a kind of traditional Chinese medicine,which has been widely used in the treatment of kinds of ***,there is still a lack of systematic understanding of the molecular mechanism of Xihuang pill in the treatment of liver *** this work,we aim to explore the molecular mechanism of Xihuang pill in treating liver ***:The functional components in Xihuang pill were collected from Traditional Chinese Medicine Database and Analysis *** target genes of these components were also collected using Traditional Chinese Medicine Database and Analysis *** target genes of liver cancer were predicted using GeneCards *** intersecting genes were then analyzed with Venn *** Encyclopedia of Genes and Genomes and Database for Annotation,Visualization,and Integrated Discovery were used to analyze the ***,cell counting kit-8 was used to measure the half-maximal inhibitory concentration of Xihuang *** living dead cell staining method was used to observe the survival of ***2 cell apoptosis was tested by flow cytometry with fluorescein isothiocyanate/propidium iodide double staining method,and then the mitochondrial damage was also detected by flow *** expression of target genes was detected by quantitative real-time polymerase chain ***:A total of 130 compounds and 198 genes were identified as potential active ingredients and putative liver cancer‑related *** obtained 1,899 disease targets and 297 transcriptome targets from the *** drug-disease intersecting genes,CCNB1,BIRC5,TOP2A,ESR1,IGF2 and IGFBP3 were *** are enrichment in apoptosis,PI3K-AKT signaling pathway,MAPK signaling pathway,pathways in cancer and p53 signaling ***,it was found that the apoptosis rate of the hepG2 cells in Xihuang pill treated group was significantly higher than that of the control *** the apoptosis rate gradually increased in a dose depe

关键词： Xihuang pill liver cancer network pharmacology p53 signal pathway apoptosis-multiple species pathway

Recent progress in constructing fluorinated solid-electrolyte interphases for stable lithium metal anodes

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 270-291页

作者： Di Zhang Pengfei Lv Wei Qin xin he Yuanhua he Civil Aircraft Fire Science and Safety Engineering Key Laboratory of Sichuan Province College of Civil Aviation Safety EngineeringCivil Aviation Flight University of ChinaGuanghan 618307China School of Chemical Engineering Sichuan UniversityChengdu 610065China

Lithium metal batteries(LMBs)are emerging as a promising energy storage solution owing to their high energy density and specific ***,the non-uniform plating of lithium and the potential rupture of the solid-electrolyte interphase(SEI)during extended cycling use may result in dendrite growth,which can penetrate the separator and pose significant short-circuit *** a stable SEI is essential for the long-term operation of the ***-rich SEI has garnered significant attention for its ability to effectively passivate electrodes,regulate lithium deposition,and inhibit electrolyte *** the structural components and preparation methods of existing fluorinated SEI is crucial for optimizing lithium metal anode *** paper reviews the research on optimizing LiF passivation interfaces to protect lithium metal *** focuses on four types of compositions in fluorinated SEI that work synergistically to enhance SEI *** instance,combining compounds with LiF can further enhance the mechanical strength and ionic conductivity of the *** metals with LiF significantly improves electrochemical performance at the SEI/anode interface,with a necessary focus on reducing electron tunneling ***,incorporating polymers with LiF offers balanced improvements in interfacial toughness and ionic conductivity,though maintaining structural stability over long cycles remains a critical area for future *** alloys combined with LiF increase surface energy and lithium affinity,challenges such as dendrite growth and volume expansion *** summary,this paper emphasizes the crucial role of interfacial structures in LMBs and offers comprehensive guidance for future design and development efforts in battery technology.

关键词： LiF lithium metal anodes solid-electrolyte interphase interface cycling stability

Gradient maturation experiment on hairs implies taphonomic changes in fossil hairs

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2025年第1期68卷 62-73页

作者： xin LI Yibo ZHOU Tao ZHAO xingjian he Yanhong PAN State Key Laboratory for Mineral Deposits Research Center for Critical Earth Material Cycling Centre for Research and Education on Biological Evolution and Environment and Frontiers Science School of Earth Sciences and Engineering Nanjing University Institute of Palaeontology Yunnan Key Laboratory of Earth System Science Yunnan Key Laboratory for PalaeobiologyYunnan University

Mammalian hair, as a key feature related to endothermy, physical protection, and camouflage, has a long geohistorical record that dates back even to the Mesozoic. However, the limited information on the taphonomy of hair hinders the understanding of its evolutionary significance in deep time. To address this, we conducted taphonomic experiments to simulate the transformation process of black hair. The changes in the morphological structure, microscopic characteristics, and chemical composition of hair during the simulated fossilization process were documented by scanning electron microscopy, Fourier transform infrared(FTIR) spectroscopy, and Raman spectroscopy. Our results revealed that damage to the morphology of hair began at a mild temperature(150–175°C), and hair transformed into a fluid-like mass at a relatively high temperature(200°C). In addition, the morphological structure of melanosomes had relatively greater preservation potential than keratins did, and the microscopic features of melanosomes were persistently stable. The Raman and FTIR spectra indicated that the characteristic melanin and keratin peaks changed as the temperature increased. Although the chemical signals were not lost completely, the variations in the characteristic amide bands in the FTIR spectra indicate that the keratins severely degraded at high temperatures(>200°C), whereas the characteristic melanin bands in the Raman spectra suggested that melanin signals were still recognizable, even at high temperatures(>200°C). These results were confirmed by principal component analysis(PCA) and principal component analysis linear discriminant analysis(PCA–LDA). In addition, the Raman signals of all the samples in the simulated experiments were distinguished from the signals of common geological carbonaceous materials(humic acid), which suggested that Raman spectroscopy can be used to detect melanin in fossils.

关键词： Mammalian hair Melanin Keratin Fossilization Experimental taphonomy

Multi-objective Optimization of Elastic Beams For Minimum Weight and Sound Radiation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Multi-objective Optimization of Elastic Beams For Minimum We...

Bilevel Optimal Scheduling of Island Integrated Energy System Considering Multifactor Pricing

第十届动力学与控制学术会议

作者： meng-xin he Fu-Rui Xiong Yousef Naranjani Qian Ding Jian-Qiao Sun Department of Mechanics Tianjin University Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China School of Engineering University of California Merced

Engineering structures are often designed and optimized to meet multiple and possibly conflicting objectives such as the minimum weight and maximum strength. The merit of multiobjective optimization is to obtain a wide range of choices of structural design so that the best trade-off among different objectives can be achieved. This paper presents a multi-objective optimization of elastic beams for minimum radiated sound power and weight. The transfer matrix method is used to compute the structural and acoustic responses of the beam accurately andefficiently. Both Euler-Bernoulli and Timoshenko models are considered. The multi-objective particle swarm optimization technique is applied to search the Pareto optimal solutions representing various compromises between the weight and sound radiation. Several constraints are imposed, which substantially reduce the volume fraction of feasible solutions in the design space. Two cases of elastic beams with different boundary conditions are studied to demonstrate the multi-objective optimal designs of the structure. We have discovered that when the practical constraints such as the smoothness and lower bound of the fundamental frequency of the structure are imposed, the feasible solutions can be found only in a very small subset of the design space. Numerical results of multi-objective optimal design of non-uniform beams with two different boundary conditions are presented. We have shown that the optimized non-uniform beam indeed has smaller radiated sound power and radiation efficiency in the targeted frequency range as compared with the uniform beam of the same mass.

关键词： Non-uniform beam Sound radiation Transfer matrix method Multiobjective optimization Particle swarm technique

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Energy Engineering 2025年第1期122卷 349-378页

作者： xin Zhang Mingming Yao Daiwen he Jihong Zhang Peihong Yang Xiaoming Zhang School of Automation and Electrical Engineering Inner Mongolia University of Science and TechnologyBaotou014010China

In this paper,a bilevel optimization model of an integrated energy operator(IEO)–load aggregator(LA)is constructed to address the coordinate optimization challenge of multiple stakeholder island integrated energy system(IIES).The upper level represents the integrated energy operator,and the lower level is the electricity-heatgas load *** to the benefit conflict between the upper and lower levels of the IIES,a dynamic pricing mechanism for coordinating the interests of the upper and lower levels is proposed,combined with factors such as the carbon emissions of the IIES,as well as the lower load interruption *** price of selling energy can be dynamically adjusted to the lower LA in the mechanism,according to the information on carbon emissions and load interruption *** benefits and win-win situations are achieved between the upper and lower ***,CPLEX is used to iteratively solve the bilevel optimization *** optimal solution is selected according to the joint optimal discrimination *** results indicate that the sourceload coordinate operation can reduce the upper and lower operation *** the proposed pricingmechanism,the carbon emissions and load interruption power of IEO-LA are reduced by 9.78%and 70.19%,respectively,and the capture power of the carbon capture equipment is improved by 36.24%.The validity of the proposed model and method is verified.

关键词： Bilevel optimal scheduling load aggregator integrated energy operator carbon emission dynamic pricing mechanism