检索结果-南通市图书馆

Location of Zeros for the Weak Solution to a p-Ginzburg-Landau Problem

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

Communications in Mathematical Research 2018年第4期34卷 363-370页

作者： zhan de-sheng wang chun-peng Department of Basic Maanshan Technical CollegeMaanshanAnhui243031 不详

This paper is concerned with the asymptotic behavior of the solution με of a p-Ginzburg-Landau system with the radial initial-boundary data. The author proves that the zeros of με in the parabolic domain B1（0） × （0, T] locate near the axial line {0} x （0, T]. In particular, all the zeros converge to this axial line when the parameter ε goes to zero.

关键词： p-Ginzburg-Landau equation initial-boundary value problem location of zero

Parameter identification and global sensitivity analysis of Xin'anjiang model using meta-modeling approach

在线全文

学校读者我要写书评

暂无评论

Water Science and Engineering 2013年第1期6卷 1-17页

作者： Xiao-meng SONG Fan-zhe KONG Che-sheng zhan Ji-wei HAN Xin-hua zhanG Hydrology and Water Resources Department Nanjing Hydraulic Research Institute School of Resource and Earth Science China University of Mining and Technology Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University

Parameter identification, model calibration, and uncertainty quantification are important steps in the model-building process, and are necessary for obtaining credible results and valuable information. Sensitivity analysis of hydrological model is a key step in model uncertainty quantification, which can identify the dominant parameters, reduce the model calibration uncertainty, and enhance the model optimization efficiency. There are, however, some shortcomings in classical approaches, including the long duration of time and high computation cost required to quantitatively assess the sensitivity of a multiple-parameter hydrological model. For this reason, a two-step statistical evaluation framework using global techniques is presented. It is based on （1） a screening method （Morris） for qualitative ranking of parameters, and （2） a variance-based method integrated with a meta-model for quantitative sensitivity analysis, i.e., the Sobol method integrated with the response surface model （RSMSobol）. First, the Morris screening method was used to qualitatively identify the parameters＇ sensitivity, and then ten parameters were selected to quantify the sensitivity indices. Subsequently, the RSMSobol method was used to quantify the sensitivity, i.e., the first-order and total sensitivity indices based on the response surface model （RSM） were calculated. The RSMSobol method can not only quantify the sensitivity, but also reduce the computational cost, with good accuracy compared to the classical approaches. This approach will be effective and reliable in the global sensitivity analysis of a complex large-scale distributed hydrological model.

关键词： Xin'anjiang model," global sensitivity analysis parameter identification meta-modeling approach," response surface model

Investigation on the relationship between hydraulic loss and vortex evolution in pump mode of a pump-turbine

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2022年第4期34卷 555-569页

作者： Yong-lin Qin De-you Li Hong-jie Wang zhan-sheng Liu Xian-zhu Wei Xiao-hang Wang School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China State Key Laboratory of Hydro-Power Equipment Harbin Institute of Large Electrical MachineryHarbin 150040China

Hydraulic loss and vorticity are two most common methods in analyzing the flow characteristics in hydro-machine,i.e.,centrifugal pump,Francis turbine,*** the relationship and correlation between hydraulic loss and vortex evolution are not uncovered *** this study,hydraulic loss is regarded as the combination of dissipation effect and transportation effect in flow ***,vorticityωcan be decomposed into two parts,namely the Liutex partω_(R),the shear partωs,of whichω_(R)is regarded as the third-generation vortex identification method for its precise and rigorous definition of local rigid rotation part of *** on the dimensional analysis,two new physical quantities related to vorticity(ω,ω_(R)andωS),namely enstrophyΩ,vorticity transport intensity T are adopted to express the energy characteristic in vortex evolution ***,operating points at pump mode of an ultra-high head reversible pump-turbine are selected as the research object and the numerical results calculated using SST k-ωturbulence model are consistent well with the experimental *** correlation coefficient is adopted to evaluate the correlation between hydraulic loss and vortex evolution in main flow *** show that apart from the spiral casing domain,the enstrophy of shear partΩs has very strong correlation with dissipation effect and Liutex transport intensity TR has stronger correlation with transportation effect when compared with other forms of *** correlation between Liutex transport intensity TR and transportation effect is strong in stay/guide vanes(SGVs)while reduce to medium level in runner and draft tube *** spiral casing domain,all forms of vorticity show weak or very weak correlation with transportation *** on the proposed method,we believe that the relationship and correlation between hydraulic loss and vortex evolution in other hydraulic machineries can also be clearly investigated.

关键词： Hydraulic loss enstrophy vorticity transportation pearson correlation coefficient

Improving Removal Efficiency of Organic Matters by Adding Phosphorus in Drinking Water Biofiltration Treatment

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

Biomedical and Environmental Sciences 2003年第1期16卷 29-39页

作者： XIN YU, XIAO-JIAN zhanG, AND zhan-sheng WANGDepartment of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China Department of Environmental Science and Engineering Tsinghua University 北京 100084

Objective To investigate phosphorus limitation and its effect on the removal efficiency of organic matters in drinking water biological treatment. Methods Bacterial growth potential (BGP) method and a pair of parallel pilot-scale biofilters were used for the two objectives, respectively. Results The addition of phosphorus could substantially increase the BGPs of the water samples and the effect was stronger than that of the addition of carbon. When nothing was added into the influents, both CODMn removals of the parallel biofilters (BF1 and BF2) were about 15%. When phosphate was added into its influent, BF1 performed a CODMn removal, 6.02 percentage points higher than the control filter (BF2) and its effluent had a higher biological stability. When the addition dose was <20μg. L-1, no phosphorus pollution would occur and there was a good linear relationship between the microbial utilization of phosphorus and the removal efficiency of organic matters. Conclusions Phosphorus was a limiting nutrient and its limitation was stronger than that of carbon. The addition of phosphate was a practical way to improve the removal efficiency of organic matters in drinking water biological treatment.

关键词： Drinking water Biofiltration Phosphorus Limiting nutrient Organic matters Biological stability

Research Development of Endocrine Disrupting Chemicals(EDCs) in Water in China

在线全文

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 2003年第1期16卷 62-67页

作者： HONG ZHOU, XIAO-JIAN zhanG, AND zhan-sheng WANGDepartment of Environmental Sciences and Engineer, Tsinghua University, Beijing 100084, China Department of Environmental Sciences and Engineer Tsinghua University Beijing 100084 Chin

More and more importance has been attached to the problem of endocrine disrupting chemicals (EDCs) since 1960s. This article elaborates the recent research progress of EDCs in water and the trends in the near future i... 详细信息

关键词： Endocrine disrupting chemicals Source water Alkylphenols Phthalates Atrazine

A Special Additive Enables All Cations and Anions Passivation for Stable Perovskite Solar Cells with Efficiency over 23%

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2021年第11期13卷 142-154页

作者： Wenjing Zhao Jie Xu Kun He Yuan Cai Yu Han Shaomin Yang sheng zhan Dapeng Wang Zhike Liu shengzhong Liu Key Laboratory of Applied Surface and Colloid Chemistry Ministry of EducationShaanxi Key Laboratory for Advanced Energy DevicesShaanxi Engineering Lab for Advanced Energy TechnologySchool of Materials Science&EngineeringShaanxi Normal UniversityXi’an 710119People’s Republic of China Dalian National Laboratory for Clean Energy iChEMDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023People’s Republic of China

Passivating undercoordinated ions is an effective way to reduce the defect densities at the surface and grain boundaries(GBs)of perovskite materials for enhanced photovoltaic performance and stability of perovskite solar cells(PSCs).Here,(BBF)complex is chosen as a multifunctional additive,which contains both C7H9N and BF3 groups working as Lewis base and Lewis acid,respectively,can bond with Pb^(2+)/I^(−) and FA+on the surface and in the GBs in the perovskite film,affording passivation of both cation and anion *** synergistic effect of the C7H9N and BF3 complex slows the crystallization during the perovskite film deposition to improve the crystalline quality,which reduces the trap density and the recombination in the perovskite film to suppress nonradiative recombination loss and minimizes moisture permeation to improve the stability of the perovskite ***,such an additive improves the energy-level alignment between the valence band of the perovskite and the highest occupied molecular orbital of the hole-transporting material,***,our work achieves power conversion efficiency of 23.24%,accompanied by enhanced stability under ambient conditions and light illumination and opens a new avenue for improving the performance of PSCs through the use of a multifunctional complex.

关键词： Additives Simultaneous passivation Combined effects High efficiency Perovskite solar cells

Hydropathy modulation on Bi_(2)S_(3) for enhanced electrocatalytic CO_(2) reduction

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2023年第3期42卷 806-812页

作者： Long-sheng zhan Yu-Chao Wang Meng-Jie Liu Xin Zhao Jiao Wu Xiang Xiong Yong-Peng Lei State Key Laboratory of Powder Metallurgy Powder Metallurgy Research InstituteCentral South UniversityChangsha 410083China School of Material Science and Engineering Central South University of Forestry and Technology

Electrochemical CO_(2) reduction reaction(CO_(2)RR)is a promising way to achieve carbon ***,the activity and selectivity of CO_(2)RR are limited by not only the development of earth-abundant catalysts but also the CO_(2) mass transfer during the CO_(2)RR ***,Bi_(2)S3 nanorods were synthesized under a relatively mild ***,benefitting to the modulation of the hydropathy.

关键词： process neutral selectivity

Spectral filtering of dual lasers with a high-finesse length-tunable cavity for rubidium atom Rydberg excitation

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2021年第7期30卷 261-268页

作者： Yang-Yang Liu Zhuo Fu Peng Xu Xiao-Dong He Jin Wang Ming-sheng zhan State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan 430071China University of Chinese Academy of Sciences Beijing 100049China

We propose and demonstrate an alternative method for spectral filtering and frequency stabilization of both 780-nm and 960-nm lasers using a high-finesse length-tunable cavity(HFLTC).Firstly,the length of HFLTC is stabilized to a commercial frequency ***,the two lasers are locked to this HFLTC using the Pound–Drever–Hall(PDH)method which can narrow the linewidths and stabilize the frequencies of both lasers ***,the transmitted lasers of HFLTC with each power up to about 100μW,which act as seed lasers,are amplified using the injection locking method for single-atom Rydberg *** linewidths of obtained lasers are narrowed to be less than 1 k Hz,meanwhile the obtained lasers'phase noise around 750 k Hz are suppressed about 30 d *** the spectrally filtered lasers,we demonstrate a Rabi oscillation between the ground state and Rydberg state of single-atoms in an optical trap tweezer with a decay time of(67±37)μs,which is almost not affected by laser phase *** found that the maximum short-term laser frequency fluctuation of a single excitation lasers is at~3.3 k Hz and the maximum long-term laser frequency drift of a single laser is~46 k Hz during one *** work develops a stable and repeatable method to provide multiple laser sources of ultra-low phase noise,narrow linewidth,and excellent frequency stability,which is essential for high precision atomic experiments,such as neutral atom quantum computing,quantum simulation,quantum metrology,and so on.

关键词： laser frequency stabilization spectral filtering Rydberg state rubidium atom

Optimal Tracking Performance With Model Uncertainty Over A Quantized Control Input

在线全文

学校读者我要写书评

暂无评论

Optimal Tracking Performance With Model Uncertainty Over A Q...