检索结果-南通市图书馆

Exact Tail Asymptotics for a Discrete-time Preemptive Priority Queue

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2015年第1期31卷 43-58页

作者： yang song Zai-ming LIU Hong-shuai DAI School of Mathematics and Statistics Central South University School of Statistics Shandong University of Finance and Economics

In this paper, we consider a discrete-time preemptive priority queue with different service com- pletion probabilities for two classes of customers, one with high-priority and the other with low-priority. This model corresponds to the classical preemptive priority queueing system with two classes of independent Poisson customers and a single exponential server. Due to the possibility of customers＇ arriving and departing at the same time in a discrete-time queue, the model considered in this paper is more complicated than the continuous- time model. In this model, we focus on the characterization of the exact tail asymptotics for the joint stationary distribution of the queue length of the two types of customers, for the two boundary distributions and for the two marginal distributions, respectively. By using generating functions and the kernel method, we get the exact tail asymptotic properties along the direction of the low-priority queue, as well as along the direction of the high-priority queue.

关键词： discrete-time queue stationary distribution kernel method exact tail asymptotics

Mn-modified nitrogen-doped Pt-based electrocatalyst for efficient oxygen reduction in aluminum-air batteries

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第8期17卷 7126-7135页

作者： Li Gao yang song Xuebing Xu Chang Li Chaoquan Hu State Key Laboratory of Mesoscience and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China Zhongke Nanjing Institute of Green Manufacturing Industry Nanjing 211135China

In this study,a Mn-modified Pt-based catalyst loaded on nitrogen-doped Ketjen black(Mn-Pt/NKB)is prepared using a simple ethylene glycol reduction *** size of Pt nanoparticles(NPs)is effectively controlled by doping with Mn and *** the smallest average particle size of 1.7 nm,Mn-Pt/NKB demonstrates half-wave potentials of 0.890 and 0.688 V in the alkaline and neutral electrolytes,respectively,which are superior to those of commercial platinum on activated carbon(Pt/C).When applied as an air cathode in aluminum-air battery,it exhibits ultra-high power densities of 190(alkaline)and 26.2 mW·cm^(−2)(neutral).Moreover,the voltage remains stable after 5 h of *** practical application performance of the Mn-Pt/NKB catalyst in an aluminum-air battery is better than that of commercial Pt/***,the oxygen reduction reaction(ORR)mechanism on surfaces with different particle sizes is analyzed using density functional *** cracking is the major pathway on the surface of the small particles with lower energy consumption of 0.5 eV,while water molecule cleavage is the major pathway on the surface of the large particles with higher energy consumption of 0.97 *** lower energy consumption of the oxygen cracking pathway further confirms the ORR mechanism for higher activity on small-sized *** study provides a direction for the rational design of Pt-based catalysts for ORR and sheds light on the commercial development of aluminum-air batteries.

关键词： oxygen reduction reaction precious metal catalysts aluminum-air battery density functional theory(DFT)calculations reaction pathway

Chlorobenzenes and organochlorinated pesticides in vegetable soils from an industrial site, China

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

Journal of Environmental Sciences 2012年第3期24卷 362-368页

作者： yang song Fang Wang Yongrong Bian Yinping Zhang Xin Jiang State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China

Organochlorinated compounds are ubiquitous contaminants in the environment, especially in industrial sites. The objective of the work was to investigate whether a vegetable field near an industrial site is safe for vegetable production. The residues of chlorobenzenes （CBs）, hexachlorocyclohexanes （HCHs） and dichlorodiphenyltrichloroethanes （DDTs） in a vegetable field which was near a chemical plant in China were characterized. Point estimate quotient was used for ecological risk assessment of the investigated site. The results showed that all CBs except monochlorobenzene （MCB） were detected in soils. The total concentrations of ∑ CBs ranged from 71.06 to 716.57 ng/g, with a mean concentration of 434.93 ng/g. The main components of CBs in soil samples were dichlorobenzenes （DCBs）, trichlorobenzenes （TCBs） and tetrachlorobenzenes （TeCBs）, while for single congeners, 1,2,4-TCB had the highest concentration, which ranged from 13.21 to 210.35 ng/g with a mean concentration of 111.89 ng/g. Residues of hexachlorobenzene （HCB） in soil samples ranged from 0.9 to 11.79 ng/g, significantly lower than ∑ DCB, ∑ TCB and ∑ TeCB. Concentrations of ∑ HCHs and ∑ DDTs in soils ranged from 11.32 to 55.24 ng/g and from 195.63 to 465.58 ng/g, respectively, of which the main components were α-HCH and p,p＇-dichlorodiphenyldichloroethylene （p,p＇-DDE）. Ecological risk assessment for the investigated site showed that the most potential risks were from TCBs and TeCBs, based on the hazard quotients. The higher residues of CBs and DDTs compared to the target values and the higher than 1 hazard quotients indicated that this area is not safe for vegetable production and thus soil remediation is needed.

关键词： chlorobenzenes hexachlorocyclohexanes dichlorodiphenyltrichloroethanes degradation risk assessment

Bile acids,gut microbiota,and therapeutic insights in hepatocellular carcinoma

在线全文

学校读者我要写书评

暂无评论

Cancer Biology & Medicine 2024年第2期21卷 144-162页

作者： yang song Harry CH Lau Xiang Zhang Jun Yu Institute of Digestive Disease and Department of Medicine and Therapeutics State Key Laboratory of Digestive DiseaseLi Ka Shing Institute of Health SciencesCUHK Shenzhen Research InstituteThe Chinese University of Hong KongHong KongChina Department of Gastroenterology Zhongshan Hospital Xiamen UniversityXiamen 361004China

Hepatocellular carcinoma(HCC)is a prevalent and aggressive liver *** interplay between bile acids(BAs)and the gut microbiota has emerged as a critical factor in HCC development and *** normal conditions,BA metabolism is tightly regulated through a bidirectional interplay between gut microorganisms and *** gut microbiota plays a critical role in BA metabolism,and BAs are endogenous signaling molecules that help maintain liver and intestinal *** note,dysbiotic changes in the gut microbiota during pathogenesis and cancer development can disrupt BA homeostasis,thereby leading to liver inflammation and fibrosis,and ultimately contributing to HCC ***,understanding the intricate interplay between BAs and the gut microbiota is crucial for elucidating the mechanisms underlying *** this review,we comprehensively explore the roles and functions of BA metabolism,with a focus on the interactions between BAs and gut microorganisms in ***,therapeutic strategies targeting BA metabolism and the gut microbiota are discussed,including the use of BA agonists/antagonists,probiotic/prebiotic and dietary interventions,fecal microbiota transplantation,and engineered *** summary,understanding the complex BA-microbiota crosstalk can provide valuable insights into HCC development and facilitate the development of innovative therapeutic approaches for liver malignancy.

关键词： Bile acid gut microbiota hepatocellular carcinoma therapeutics microbiota modulation

A numerical simulation of latent heating within Typhoon Molave

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2017年第7期36卷 39-47页

作者： LIU yang LIN Wenshi LI Jiangnan WANG Gang yang song FENG Yerong School of Atmospheric Sciences Sun Yat-sen UniversityGuangzhou 510275China Meteorological Center of Middle South Regional Air Traffic Management Bureau of Civil Aviation of China Guangzhou 510470China Guangdong Provincial Key Laboratory of Regional Numerical Weather Prediction China Meteorological AdministrationGuangzhou 510080China

The weather research and forecasting（WRF） model is a new generation mesoscale numerical model with a fine grid resolution（2 km）, making it ideal to simulate the macro-and micro-physical processes and latent heating within Typhoon Molave（2009）. Simulations based on a single-moment, six-class microphysical scheme are shown to be reasonable, following verification of results for the typhoon track, wind intensity, precipitation pattern, as well as inner-core thermodynamic and dynamic structures. After calculating latent heating rate, it is concluded that the total latent heat is mainly derived from condensation below the zero degree isotherm, and from deposition above this isotherm. It is revealed that cloud microphysical processes related to graupel are the most important contributors to the total latent heat. Other important latent heat contributors in the simulated Typhoon Molave are condensation of cloud water, deposition of cloud ice, deposition of snow, initiation of cloud ice crystals, deposition of graupel, accretion of cloud water by graupel, evaporation of cloud water and rainwater,sublimation of snow, sublimation of graupel, melting of graupel, and sublimation of cloud ice. In essence, the simulated latent heat profile is similar to ones recorded by the Tropical Rainfall Measuring Mission, although specific values differ slightly.

关键词： latent heat weather research and forecasting model Typhoon Molave thermodynamic structure cloud microphysics zero degree isotherm

Space-Time Variability and Prognosis of Soil Salinization in Yucheng City, China

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2005年第6期15卷 797-804页

作者： yang Yu-Jian yang Jing-song LIU Guang-Ming yang Xiao-Ying Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 （China）.

This research used both geostatistics and GIS approach to compare temporal change of soil salt between 1980 and 2003, to analyze the spatial distribution of surface soil salt, to developed methods for predicting soil salinization potential based on recent improvements to the Dempster-Shafer theory, and to develop probability maps of potential salinization in Yucheng City, China. A semivariogram model of soil salt content was developed from the spherical model, and then employing kriging interpolation the spatial distribution of salt content in 2003 was obtained utilizing data from 100 soil sampling points. Potential salinization distribution was mapped using an approach that integrated soil data of the second general survey in 1980 in Yucheng City, which included groundwater salinity, groundwater depth, soil texture, soil organic matter content, and geomorphic maps. With the support of Dempster-Shafer theory and fuzzy set technique the factors that affected potential soil salinization were characterized and integrated; and then soil salinization was predicted. Finally a prognosis map of potential salinization distribution in the research area was obtained, with higher probability values indicating higher hazards to salinity processes. The distribution of the potential soil salinization probability was a successive surface.

关键词： Dempster-Shafer theory GIS kriging interpolation prognosis soil salinization

Relationships　between　Regional　Indian　Summer　Monsoon　Rainfall　and　Eurasian　Snow　Cover

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 1995年第2期12卷 143-150页

作者： B. Parthasarathy song yang Indian Institute of Tropical Meteorology Pune India General Sciences Corporation A Subsidiary of Science Applications International Corporation Laurel USA

In this work,correlation analysis is applied to study the interannual relationships betWeen indian summer monsoon rainfall of different homogeneous regions and Eurasian Snow Cover(ESC) during winter and spring seasons for the time period from 1973 to *** monsoon rainfall of the western and central regions of india,as well as the all-India monsoon rainfall,is significantly negatively correlated with the ESC averaged for the monthsDecember-March and with,especially,the ESC of *** study may provide some useful information for the long-range prediction of the regional indian monsoon rainfall.

关键词： Regional Indian raipfall Eurasian snow cover Interannual relationship

[BMIM]CI Catalyzed One-Pot Synthesis of a-Aminophospho- nate Derivatives Containing a 4-Phenoxyquinazoline Moiety under Microwave Irradiation

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2011年第1期29卷 109-117页

作者： Bai, song song, Baoan Bhadury, Pinaki S. yang, song Hu, Deyu Xue, Wei Research and Development Center for Fine Chemicals Education Ministry Key Laboratory of Green Pesticide and Bioengineering Guizhou University Guiyang Guizhou 550025 China

[BMIM]Cl catalyzed three component Mannich-type reaction of 4-（quinazolin-4-yloxy）benzenamine and aldehyde with dialkyl phosphite under microwave irradiation has been described. The salient features of the reaction leading to new a-aminophosphonates include shorter reaction time and good yields. The method is environmentally friendly and does not require toxic catalysts or solvents. To the best of our knowledge, this is the first report for [BMIM]Cl induced one-pot synthesis of a-aminophosphonate derivatives.

关键词： quinazoline a-aminophosphonates [BMIM]Cl microwave chemistry multicomponent reaction

Novel 18β-glycyrrhetinic acid amide derivatives show dual-acting capabilities for controlling plant bacterial diseases through ROS-mediated antibacterial efficiency and activating plant defense responses

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

Journal of Integrative Agriculture 2023年第9期22卷 2759-2771页

作者： song Ying-lian LIU Hong-wu yang Yi-hong HE Jing-jing yang Bin-xin yang Lin-li ZHOU Xiang LIU Li-wei WANG Pei-yi yang song National Key Laboratory of Green Pesticide/Key Laboratory of Green Pesticide and Agricultural Bioengineering Ministry of Education/Center for R&D of Fine ChemicalsGuizhou UniversityGuiyang 550025P.R.China

Natural products have long been a crucial source of,or provided inspiration for new agrochemical *** occurring 18β-glycyrrhetinic acid shows broad-spectrum bioactivities and is a potential skeleton for novel drug *** extend the utility of 18β-glycyrrhetinic acid for agricultural uses,a series of novel 18β-glycyrrhetinic acid amide derivatives were prepared and evaluated for their antibacterial ***,compound 5k showed good antibacterial activity in vitro against Xanthomonas oryzae ***(Xoo,EC50=3.64 mg L–1),and excellent protective activity(54.68%)against Xoo in *** 5k induced excessive production and accumulation of reactive oxygen species in the tested pathogens,resulting in damaging the bacterial cell *** interestingly,compound 5k could increase the activities of plant defense enzymes including catalase,superoxide dismutase,peroxidase,and phenylalanine ammonia *** together,these enjoyable results suggested that designed compounds derived from 18β-glycyrrhetinic acid showed potential for controlling intractable plant bacterial diseases by disturbing the balance of the phytopathogen’s redox system and activating the plant defense system.

关键词： 18β-glycyrrhetinic acid antibacterial activities defense enzyme activity reactive oxygen species