检索结果-南通市图书馆

Formation of diffuse and spark discharges between two needle electrodes with the scattering of particles

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Plasma Science and Technology 2024年第9期26卷 32-39页

作者： victor F TARASENKO Dmitry V BELOPLOTOV Alexei N PANCHENKO Dmitry A SOROKIN Institute of High Current Electronics Siberian BranchRussian Academy of SciencesTomsk 634055Russia National Research Tomsk State University Tomsk 634050Russia

The development of a nanosecond discharge in a pin-to-pin gap filled with air at atmospheric pressure has been studied with high temporal and spatial resolutions from a breakdown start to the spark *** and negative nanosecond voltage pulses with an amplitude of tens of kilovolts were ***-resolved images of the discharge development were taken with a fourchannel Intensified Charge Coupled Device(ICCD)*** minimum delay between the camera channels could be as short as≈0.1 *** made it possible to study the gap breakdown process with subnanosecond *** was observed that a wide-diameter streamer develops from the high-voltage pointed *** ionization processes near the grounded pin electrode started when the streamer crossed half of the *** bridging the gap by the streamer,a diffuse discharge was *** development of spark leaders from bright spots on the surface of the pointed electrodes was observed at the next *** was found that the rate of development of the spark leader is an order of magnitude lower than that of the wide-diameter *** thin luminous tracks were observed against the background of a discharge plasma *** has been established that the tracks are adjacent to brightly glowing spots on the electrodes and are associated with the flight of small particles.

关键词： needle electrodes short voltage pulses atmospheric air streamer breakdown diffuse and spark discharges scattering metal particles

Network coding-aware cache replacement policy in on-demand broadcast environments

在线全文

学校读者我要写书评

暂无评论

Journal of Harbin Institute of Technology(New Series) 2012年第5期19卷 92-100页

作者：陈君 LEE victor C S CHAN Edward School of Information Management Wuhan UniversityWuhan 430072China Dept.of Computer Science City University of Hong KongHong KongChina

Network coding has been proved to be an effective technique in improving the performance of data broadcast systems because clients requesting different data items can be served simultaneously in one broadcast. Previous studies showed that its efficiency is highly related to the content of clients' cache. However, existing data broadcast systems do not take network coding information into account when making cache replacement decisions. In this paper, we propose two networks coding-aware cache replacement policies called DLRU and DLRU-CP to supplement network coding assisted data broadcast in on-demand broadcast environments. In DLRU, both data access and decoding contribution are taken into account to make replacement decisions. DLRU-CP is based on DLRU but allows clients to retrieve decodable data items that have not been requested yet. The performance gain of our proposed cache replacement policies over traditional cache replacement policy is shown in the simulation results, which demonstrate conclusively that the proposed policies can effectively reduce the overall response time.

关键词： Network coding cache replacement on-demand broadcast mobile computing

Impact of Trans-Atlantic-Pacific Ocean Dipole–like pattern on summer precipitation variability over West Africa

在线全文

学校读者我要写书评

暂无评论

Atmospheric and Oceanic Science Letters 2018年第6期11卷 509-517页

作者： LIN Zhao-Hui victor Nnamdi DIKE International Center for Climate and Environment Sciences Institute of Atmospheric Physics Chinese Academy of Sciences College of Earth Science University of Chinese Academy of Sciences Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and Technology Energy Climate and Climate and Environment Sciences Group Imo State Polytechnic Umuagwo

Recent findings indicate that rainfall variability over West Africa is characterized by more positive anomalies in the last four *** authors demonstrate that the recent interannual rainfall variability is linked to an air–sea phenomenon that occurs in the tropical Atlantic and eastern Pacific Ocean,and then propose the Trans-Atlantic-Pacific Ocean Dipole(TAPOD)index as a measure for this tropical ocean phenomenon,which is found to be closely correlated with the West African summer rainfall *** observational and reanalysis datasets,composite analysis suggests that enhanced precipitation in West Africa is associated with the positive phase of the TAPOD,which is characterized by warm sea surface temperature anomalies(SSTAs)in the tropical Atlantic and cool SSTAs in the tropical eastern Pacific *** the positive phase of the TAPOD,there are significant westerly anomalies over the tropical Atlantic Ocean,which drives anomalous water vapor convergence over West Africa,leading to enhanced precipitation in the region.

关键词： Trans-Atlantic-Pacific Ocean Dipole West African summer rainfall water vapor transportation West African westerlies

Sudden sensorineural hearing loss-A contemporary review of management issues

在线全文

学校读者我要写书评

暂无评论

Journal of Otology 2020年第2期15卷 67-73页

作者： Anup Singh David victor Kumar Irugu Department of Otorhinolaryngology and Head and Neck Surgery Medanta-the MedicityGurugramHaryanaIndia Department of Otorhinolaryngology and Head and Neck Surgery All India Institute of Medical SciencesNew DelhiIndia

Sudden sensorineural hearing loss(SSNHL)is an enigmatic entity,with obscure pathophysiology and debatable efficacy of the treatment agents *** underlying cause is identified in only 10-15%of *** management of the remaining patients,classified as‘idiopathic’,is empirical,and is conventionally with systemic steroids,vasodilator therapy,rheological agents,and antioxidants,to list a few amongst the host of the agents employed for the *** availability of conflicting outcomes and lack of conclusive evidence has resulted in the propagation of consensus-based treatment *** the present review,we discuss the various controversial issues and newer developments in the management of idiopathic *** current review aims to present a narrative outlook of the updated evidence base available from PUBMED,augmented with relevant designated publications.

关键词： Hearing loss Sudden Sensorineural Instillation Drug Dexamethasone Prognosis

Isobavachalcone:An Overview

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Integrative Medicine 2012年第7期18卷 543-547页

作者： victor Kuete Louis P.Sandjo Department of Biochemistry Faculty of ScienceUniversity of Dschang Department of Organic Chemistry Faculty of ScienceUniversity of Yaounde Ⅰ

Isobavachalcone （IBC） or （E）-l-[2,4-dihydroxy-3-（3-methyl-2-butenyl）-phenyl]-3-（4- hydroxyphenyl）-2-propen-1-one or （E）-4,2＇,4＇-trihydroxy-3＇-prenylchalcone; 2＇,4,4＇-trihydroxy-3＇-prenyl-trans- chalcone, is a prenylated chalcone of the class flavonoid, firstly isolated from Psoralea corylifolia in 1968. IBC is known to possess a wide spectrum of biological activities, antibacterial, antifungal, anticancer, anti-reverse transcriptase, antitubercular and antioxidant. The compound was isolated from plant families, mostly Moraceae and Fabaceae. This review brings out together the knowledge on IBC, and can serve as the start point for future research and valorization accomplishments.

关键词： Isobavachalcone pharmacology biosynthesis synthesis

Current endoscopic approach to indeterminate biliary strictures

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2012年第43期18卷 6197-6205页

作者： David W victor Stuart Sherman Tarkan Karakan Mouen A Khashab Department of Medicine Johns Hopkins Hospital Baltimore MD 21287 United States Department of Medicine Indiana University School of Medicine Indianapolis IN 46202 United States Department of Medicine Gazi University 06710 Ankara Turkey

Biliary strictures are considered indeterminate when basic work-up, including transabdominal imaging and endoscopic retrograde cholangiopancreatography with routine cytologic brushing, are non-diagnostic. Indeterminate biliary strictures can easily be mischaracterized which may dramatically affect patient's outcome. Early and accurate diagnosis of malignancy impacts not only a patient's candidacy for surgery, but also potential timely targeted chemotherapies. A significant portion of patients with indeterminate biliary strictures have benign disease and accurate diagnosis is, thus, paramount to avoid unnecessary surgery. Current sampling strategies have suboptimal accuracy for the diagnosis of malignancy. Emerging data on other diagnostic modalities, such as ancillary cytology techniques, single operator cholangioscopy, and endoscopic ultrasonography-guided fine needle aspiration, revealed promising results with much improved sensitivity.

关键词： Indeterminate stricture Bile duct Single operator cholangioscope Cholangioscopy Endoscopic ultrasound Endoscopic retrograde cholangiopancrea-tography Bile duct stricture Indeterminate biliary stricture Confocal microscopy Transpapillary biopsy Cholangiocarcinoma Primary sclerosing cholangitis Spyglass

Factors associated with patient absenteeism for scheduled endoscopy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2009年第23期15卷 2882-2886页

作者： victor K Wong Hong-Bin Zhang Robert Enns St. Paul's Hospital Universityof British Columbia Vancouver V6Z-2K5 BC Canada Centre for Health Evaluation and OutcomesSciences St. Paul's Hospital University of British ColumbiaVancouver V6Z-2K5 BC Canada

AIM: To identify risk factors to help predict which patients are likely to fail to appear for an endoscopic procedure. METHODS: This was a retrospective, chart review, cohort study in a Canadian, tertiary care, academic, hospital-based endoscopy clinic. Patients included were: those undergoing esophagogastroduodenoscopy, colonoscopy or flexible sigmoidoscopy and patients who failed to appear were compared to a control group. The main outcome measure was a multivariate analysis of factors associated with truancy from scheduled endoscopic procedures. Factors analyzed included gender, age, waiting time, type of procedure, referring physician, distance to hospital, first or subsequent endoscopic procedure or encounter with gastroenterologist, and urgency of the procedure. RESULTS: Two hundred and thirty-four patients did not show up for their scheduled appointment. Compared to a control group, factors statistically significantly associated with truancy in the multivariate analysis were: non-urgent vs urgent procedure (OR 1.62, 95% CI 1.06, 2.450), referred by a specialist vs a family doctor (OR 2.76, 95% CI 1.31, 5.52) and office-based consult prior to endoscopy vs consult and endoscopic procedure during the same appointment (OR 2.24, 95% CI 1.33, 3.78). CONCLUSION: Identifying patients who are not scheduled for same-day consult and endoscopy, those referred by a specialist, and those with non-urgent referrals may help reduce patient truancy.

关键词： Absenteeism Colonoscopy Endoscopy Esophagogastroduodenoscopy Gastroenterologist

Pathways for Sustainable Utilization of Waste Chicken Eggshell

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 Renewable Materials 2022年第8期10卷 2217-2246页

作者： Omojola Awogbemi Daramy Vandi Von Kallon victor Sunday Aigbodion Department of Mechanical and Industrial Engineering Technology University of JohannesburgJohannesburgSouth Africa African Centre of Excellence ACESPED University of NigeriaNsukkaNigeria Faculty of Engineering and the Built Environment University of JohannesburgJohannesburgSouth Africa

Chicken eggshell is one of the most common wastes generated from households,restaurants and other food processing *** Chicken Eggshells(WCES)also constitutes an environmental nuisance and ends up discarded at dumping site with no consideration of further *** main constituent of WCES is calcium carbonate from which calcium or calcium oxide can be extracted for various *** current effort reviews recently published literature on the diverse applications of *** considered utilization avenues include catalysts for biofuel production,construction industry,wastewater purification,industrial sector,food industry,medical,and agricultural *** specific areas of application apart from the transesterification reactions include cement additives and replacement in concrete,asphalt binder,adsorbent of metals and dyes,production of hydroxyapatite,food supplement and fortification,dentistry,therapeutics,bone formation,drug delivery,poultry feeds as well as organic *** most of the identified applications,the WCES is subjected to pretreatment and other modification techniques before *** conversion of WCES to valuable products is a cost-effective,safe,environmentally friendly,non-toxic and viable means of waste disposal and *** investigations are needed to further explore the benefits derivable from this bioresource.

关键词： Waste chicken eggshells catalysts food supplements medical applications waste utilization biofuel production

Spontaneous combustion influenced by surface methane drainage and its prediction by rescaled range analysis

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 Mining Science and Technology 2018年第2期28卷 215-221页

作者： Shengqiang Yang Xincheng Hu Wei victor Liu Jiawen Cai Xiuhong Zhou School of Safety Engineering China University of Mining&TechnologyXuzhou 221008China Key Laboratory of Gas and Fire Control for Coal Mines Xuzhou 221008China Department of Civil&Environmental Engineering University of AlbertaEdmonton T6G 2W2Canada

This study established numerical modeling using COMSOLTMto examine the influence of horizontal location and drainage ability of surface borehole on spontaneous combustion in longwall working face gob. Rescaled Range Analysis(R/S analysis) was employed to investigate the chaos characteristic of N_2/O_2 ratio from a surface borehole in 10416 working face gob, Yangliu Colliery, China. The simulation results show that there is always a circular ‘‘dissipation zone" around the drainage borehole and an elliptic ‘‘spontaneous combustion zone" in deep gob. Little influence was found on spontaneous combustion zone on the intake side of the gob but the width of spontaneous combustion zone in middle gob is enlarged, while the depth of spontaneous combustion zone near the return side is reduced. The R/S analysis indicates that the influence of surface borehole on spontaneous combustion can be divided into two stages by the chaos feature of N_2/O_2: safety drainage stage and spontaneous combustion initiating stage. It can be concluded that the methane drainage from gob through surface borehole can intervene in the distribution of spontaneous combustion zone in gob and the chaos feature of N_2/O_2 from surface borehole can effectively reflect coal spontaneous combustion condition in gob.

关键词： Coal spontaneous combustion Surface drainage borehole Hurst index Rescaled range analysis Methane drainage Symbiotic disaster