检索结果-南通市图书馆

Charney’s Model—the Renowned Prototype of Baroclinic Instability—Is Barotropically Unstable As Well

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2019年第7期36卷 733-752页

作者： yuan-bing ZHAO X.San LIANG School of Atmospheric Sciences Nanjing University of Information Science and TechnologyNanjing210044China School of Marine Sciences Nanjing University of Information Science and TechnologyNanjing210044China School of Mathematics and Statistics Nanjing University of Information Science and TechnologyNanjing210044China

The Charney model is reexamined using a new mathematical tool, the multiscale window transform(MWT), and the MWT-based localized multiscale energetics analysis developed by Liang and Robinson to deal with realistic geophysical fluid flow processes. Traditionally, though this model has been taken as a prototype of baroclinic instability, it actually undergoes a mixed one. While baroclinic instability explains the bottom-trapped feature of the perturbation, the second extreme center in the perturbation field can only be explained by a new barotropic instability when the Charney–Green number γ 1, which takes place throughout the fluid column, and is maximized at a height where its baroclinic counterpart stops *** giving way of the baroclinic instability to a barotropic one at this height corresponds well to the rectification of the tilting found on the maps of perturbation velocity and pressure. Also established in this study is the relative importance of barotropic instability to baroclinic instability in terms of γ. When γ 1, barotropic instability is negligible and hence the system can be viewed as purely baroclinic;when γ 1, however, barotropic and baroclinic instabilities are of the same order;in fact, barotropic instability can be even stronger. The implication of these results has been discussed in linking them to real atmospheric processes.

关键词： Charney’s model multiscale window transform canonical transfer baroclinic instability barotropic instability

Genome-wide identification and characterization of phospholipase C gene family in cotton (Gossypium spp.)

在线全文

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2018年第1期61卷 88-99页

作者： bing Zhang Yanmei Wang Jin-yuan Liu Laboratory of Plant Molecular Biology Center for Plant Biology School of Life Sciences Tsinghua University

Phospholipase C (PLC) are important regulatory enzymes involved in several lipid and Ca2+-dependent signaling *** studies have elucidated the versatile roles of PLC genes in growth, development and stress responses of many plants, however, the systematic analyses of PLC genes in the important fiber-producing plant, cotton, are still deficient. In this study,through genome-wide survey, we identified twelve phosphatidylinositol-specific PLC (PI-PLC) and nine non-specific PLC (NPC) genes in the allotetraploid upland cotton Gossypium hirsutum and nine PI-PLC and six NPC genes in two diploid cotton G. arboretum and ***, respectively. The PI-PLC and NPC genes of G. hirsutum showed close phylogenetic relationship with their homologous genes in the diploid cottons and Arabidopsis. Segmental and tandem duplication contributed greatly to the formation of the gene family. Expression profiling indicated that few of the PLC genes are constitutely expressed, whereas most of the PLC genes are preferentially expressed in specific tissues and abiotic stress conditions. Promoter analyses further implied that the expression of these PLC genes might be regulated by MYB transcription factors and different *** results not only suggest an important role of phospholipase C members in cotton plant development and abiotic stress response but also provide good candidate targets for future molecular breeding of superior cotton cultivars.

关键词： cotton phospholipase C gene duplication fiber development stress response

Specification and Verification of the Zab Protocol with TLA+

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2020年第6期35卷 1312-1323页

作者： Jia-qi Yin Hui-Biao Zhu yuan Fei Shanghai Key Laboratory of Trustworthy Computing East China Normal UniversityShanghai 200062China College of Information Mechanical and Electrical EngineeringShanghai Normal UniversityShanghai 200234China

ZooKeeper Atomic Broadcast (Zab) is an atomic broadcast protocol specially designed for ZooKeeper, which supports additional crash recovery. This protocol actually has been widely adopted by famous Internet companies, but there are few studies on the correctness and credibility of the Zab protocol, and thus we utilize formal methods to study the correctness. In this paper, Zab, Paxos and Raft are all analyzed and compared to help better understand the Zab protocol. Then we model the Zab protocol with TLA+ and verify three properties abstracted from the specification by the model checker TLC, including two liveness properties and one safety property. The final experimental results can prove that the design of the protocol conforms to the original requirements. This paper makes up for the analysis of formal methods in the Zab protocol.

关键词： Zab protocol TLA+ specification verification

Effects of natural organic matter on cadmium mobility in paddy soil: A review

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 Environmental Sciences 2021年第6期33卷 204-215页

作者： Chaolei yuan qi Li Zhaoyang Sun Hongwen Sun Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria Tianjin Key Laboratory of Environmental Remediation and Pollution ControlCollege of Environmental Science and EngineeringNankai UniversityTianjin 300350China

Cadmium(Cd) contamination in paddy soil has caused public concern. The uptake of Cd by rice plants depends on soil Cd mobility, which is in turn substantially influenced by organic matter(OM). In this review, we first summarize the fate of Cd in soil and the role of OM. We then focus on the effects of OM on Cd mobility in paddy soil and the factors influencing the remedial effectiveness of OM amendments. We further discuss the performance of straw incorporation in the remediation of Cd-contaminated paddy soils reported in laboratory and field studies. Considering the huge production of organic materials(such as straw) in agriculture, the use of natural OM for soil remediation has obvious appeal due to the environmental benefits and low cost. Although there have been successful application cases, the properties of OM amendments and soil can significantly affect the remedial performance of the OM amendments. Importantly, straw incorporation alone does not often decrease the mobility of Cd in soil or the Cd content in rice grains. Careful evaluation is required when considering natural OM amendments, and the factors and mechanisms that influence their remedial effectiveness need further investigation in paddy soil with realistic Cd concentrations.

关键词： Cadmium Mobility Organic matter Paddy soil Remediation

Effects of Pairing Correlations on the Korringa Relation in Doped Fullerenes

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 1996年第11期13卷 859-862页

作者： LÜJing ZHANG Li-yuan FENG Xiao-bing Department of Physics Peking UniversityBeijing 100871

An effective attractive Hubbard model is applied to explain the observed non-Korringa relation in doped fullerenes,which leads to a reduced Pauli *** results basically agree with the experiments for K_(3)C_(60),Rb_(3)C_(60) and RbCs_(2)C_(60).It implies that the pair correlation on site possibly plays an important role in the normal state for doped fullerenes.

关键词： implies attractive Hubbard

Recent advances in FeCl_(3)-photocatalyzed organic reactions via hydrogen-atom transfer

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第9期35卷 32-40页

作者： Xiao-Ya yuan Cong-Cong Wang bing Yu Green Catalysis Center College of ChemistryZhengzhou UniversityZhengzhou 450001China National Engineering Research Center of Low-Carbon Processing and Utilization of Forest Biomass Nanjing Forestry UniversityNanjing 210037China

In recent years,FeCl_(3)-photocatalyzed direct C–H/Si–H bond functionalization reactions have attracted huge *** those transformations,chlorine radical(Cl·)could be generated from FeCl_(3)via a ligandto-metal charge transfer(LMCT)/homolysis process under light *** resulting chlorine radical subsequently acts as a hydrogen atom transfer(HAT)agent to abstract the hydrogen atom of aliphatic C–H,O–H,or Si–H bonds to give the corresponding C/Si/O-centered radicals for various organic *** this review,we summarized the recent advances in the application of FeCl_(3)as a HAT photocatalyst for the C/Si–H functionalization to construct C–C,C–N,C–Si,C–S,C–B,and C-P bonds.

关键词： FeCl_(3) Photocatalysis Ligand-to-metal charge transfer Hydrogen atom transfer Chlorine radical

A LQP BASED INTERIOR PREDICTION-CORRECTION METHOD FOR NONLINEAR COMPLEMENTARITY PROBLEMS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2006年第1期24卷 33-44页

作者： bing-sheng He Li-zhi Liao Xiao-ming yuan Department of Mathematics Nanjing University Nanjing 210093 China Department of Mathematics Hong Kong Baptist University Hong Kong China Department of Mathematics City University of Hong Kong Hong Kong China

To solve nonlinear complementarity problems （NCP）, at each iteration, the classical proximal point algorithm solves a well-conditioned sub-NCP while the Logarithmic-Quadratic Proximal （LQP） method solves a system of nonlinear equations （LQP system）. This paper presents a practical LQP method-based prediction-correction method for NCP. The predictor is obtained via solving the LQP system approximately under significantly relaxed restriction, and the new iterate （the corrector） is computed directly by an explicit formula derived from the original LQP method. The implementations are very easy to be carried out. Global convergence of the method is proved under the same mild assumptions as the original LQP method. Finally, numerical results for traffic equilibrium problems are provided to verify that the method is effective for some practical problems.

关键词： Logarithmic-Quadratic proximal method Nonlinear complementarity problems Prediction-correction Inexact criterion

Quasi-Static and Dynamic Behaviors of Helical Gear System with Manufacturing Errors

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2018年第2期31卷 106-114页

作者： bing yuan Shan Chang Geng Liu Li-Yan Wu Shaanxi Engineering Laboratory for Transmissions and Controls School of Mechanical Engineering Northwestern Polytechnical University China Shipbuilding Industry Corporation 703 Institute

Time?varying mesh stiffness(TVMS) and gear errors include short?term and long?term components are the two main internal dynamic excitations for gear transmission. The coupling relationship between the two factors is usually neglected in the traditional quasi-static and dynamic behaviors analysis of gear system. This paper investigates the influence of short?term and long?term components of manufacturing errors on quasi?static and dynamic behaviors of helical gear system considering the coupling relationship between TVMS and gear errors. The TVMS, loaded static transmission error(LSTE) and loaded composite mesh error(LCMS) are determined using an improved loaded tooth contact analysis(LTCA) model. Considering the structure of shaft, as well as the direction of power flow and bearing location, a precise generalized finite element dynamic model of helical gear system is developed, and the dynamic responses of the system are obtained by numerical integration method. The results suggest that lighter loading conditions result in smaller mesh stiffness and stronger vibration, and the corresponding resonance speeds of the system become lower. Long?term components of manufacturing errors lead to the appearance of sideband frequency components in frequency spectrum of dynamic responses. The sideband frequency components are predominant under light loading conditions. With the increase of output torque, the mesh frequency and its harmonics components tend to be enhanced relative to sideband frequency components. This study can provide effective reference for low noise design of gear transmission.

关键词： Manufacturing error Mesh stiffness Transmission error Loaded composite mesh error Vibration acceleration Sideband frequency

An assessment method of annual climatic status in China using extreme climate indices:2021 as an example

在线全文

学校读者我要写书评

暂无评论

Advances in Climate Change Research 2022年第6期13卷 868-874页

作者： Zeng-yuan GUO Li-Juan CHEN bing XIE Climate Studies Key Laboratory National Climate CenterChina Meteorological AdministrationBeijing 100081China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD) Nanjing University of Information Science&TechnologyNanjing 210044China

A proper assessment of annual climatic status(ACS)is conducive to rationally formulating disaster prevention and mitigation *** former definition of ACS lacks either information on extreme climate or an intuitive grade feature service to the *** ACS defined in the National Standard of the People's Republic of China(GBACS)only considers the accumulated climate effects of each weighted 10-d temperature/precipitation anomaly in a *** global warming,the losses caused by extreme climate events often have a significant impact on the grades of ACS,but this impact cannot be reasonably reflected by *** study proposed the assessment of ACS using extreme climate indices(extreme climate-based ACS(ECACS))and compared it with *** results indicated that GBACS and ECACS can be used to evaluate the ACS from different *** ECACS is an important supplement to the GBACS,especially considering the years with frequently occurring extreme climate *** sum of GBACS and ECACS is a reasonable and comprehensive way to evaluate the *** empirical orthogonal function(EOF)analysis indicated a uniform mode(EOF1)and a dipole mode(EOF2)in GBACS and ECACS in *** interannual variation characteristics of ECACS in northern and southern China(EOF2 pattern)are consistent with real climate features,which is conducive to providing better and more detailed regional information in the ACS forecast *** results have essential instructive and application value for ACS assessment and government decision making.

关键词： Extreme climate indices Annual climatic status Temperature Precipitation