检索结果-南通市图书馆

The influence of various grease compositions and silver nanoparticle additives on electrically induced rolling-element bearing damage

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Friction 2024年第4期12卷 796-811页

作者： Samuel bond Robert L.JACKSON German MILLS Department of Chemistry and Biochemistry Auburn UniversityAuburn 36849-5412USA Department of Mechanical Engineering Auburn UniversityAuburn 36849-5412USA

Leakage currents accelerate surface degradation of metal contacts via small scale arcing across lubricating films,but recent observations suggest that metallic nanoparticle additives in lubricants may be useful to improve contact *** findings prompted a study that examined electrically induced surface pitting of steel contacts in the presence of several lubricating greases including some containing nanometer-sized colloidal silver(Ag)*** rolling sphere-on-disk experiments were conducted under electro-tribological loads employing polyurea greases derived from mineral and synthetic base oils with and without *** forces and electrical resistance were monitored continuously during the tests;surface changes were characterized by means of optical spectroscopy,stylus profilometry,and scanning electron microscopy(SEM)including compositional analysis using energy dispersive spectroscopy(EDS).The observations demonstrate that surface pitting induced by arcing occurs mainly at the points were the rolling motion changes direction and that eroded metal is deposited along the wear ***-sized pits are formed which contain carbon and oxygen indicating that arcing causes decomposition of the hydrocarbon *** findings indicate a significant inhibition of pitting is induced by the Ag nanoparticles;some greases containing other additives exhibit a similar,although less pronounced,effect.

关键词： electric motor bearings wheel bearings electric vehicles arcing electrically induced bearing damage pitting leakage current stray current

The great catastrophe: causes of the Permo-Triassic marine mass extinction

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

National Science Review 2024年第1期11卷 37-50页

作者： Paul B.Wignall David P.G.bond School of Earth & Environment University of Leeds School of Environmental Sciences University of Hull

The marine losses during the Permo-Triassic mass extinction were the worst ever experienced. All groups were badly affected, especially amongst the benthos(e.g. brachiopods, corals, bryozoans, foraminifers,ostracods). Planktonic populations underwent a fundamental change with eukaryotic algae being replaced by nitrogen-fixing bacteria, green-sulphur bacteria, sulphate-reducing bacteria and prasinophytes. Detailed studies of boundary sections, especially those in South China, have resolved the crisis to a ～55 kyr interval straddling the Permo-Triassic boundary. Many of the losses occur at the beginning and end of this interval painting a picture of a two-phase extinction. Improved knowledge of the extinction has been supported by numerous geochemical studies that allow diverse proposed extinction mechanisms to be studied. A transition from oxygenated to anoxic-euxinic conditions is seen in most sections globally, although the intensity and timing shows regional variability. Decreased ocean ventilation coincides with rapidly rising temperatures and many extinction scenarios attribute the losses to both anoxia and high *** kill mechanisms include ocean acidification for which there is conflicting support from geochemical proxies and, even less likely, siltation(burial under a massive influx of terrigenous sediment) which lacks substantive sedimentological evidence. The ultimate driver of the catastrophic changes at the end of the Permian was likely Siberian Trap eruptions and their associated carbon dioxide emissions with consequences such as warming, ocean stagnation and acidification. Volcanic winter episodes stemming from Siberian volcanism have also been linked to the crisis, but the short-term nature of these episodes(

关键词： ocean anoxia ocean acidification siltation productivity collapse volcanic winter

Target acquisition performance in the presence of JPEG image compression

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第3期33卷 30-41页

作者： Boban bondzulic Nenad Stojanovic Vladimir Lukin Sergey A.Stankevich Dimitrije Bujakovic Sergii Kryvenko University of Defence in Belgrade Military AcademyVeljka Lukica Kurjaka 3311000 BelgradeSerbia National Aerospace University Department of Information-Communication TechnologiesChkalova 1761070 KharkivUkraine National Academy of Sciences of Ukraine Scientific Centre for Aerospace Research of the EarthOles Honchar 55-b01054 KyivUkraine

This paper presents an investigation on the effect of JPEG compression on the similarity between the target image and the background,where the similarity is further used to determine the degree of clutter in the *** new clutter metrics based on image quality assessment are introduced,among which the Haar wavelet-based perceptual similarity index,known as HaarPSI,provides the best target acquisition prediction *** is shown that the similarity between the target and the background at the boundary between visually lossless and visually lossy compression does not change significantly compared to the case when an uncompressed image is *** future work,through subjective tests,it is necessary to check whether this presence of compression at the threshold of just noticeable differences will affect the human target acquisition *** values are compared with the results of subjective tests of the well-known target Search_2 database,where the degree of agreement between objective and subjective scores,measured through linear correlation,reached a value of 90%.

关键词： JPEG compression Target acquisition performance Image quality assessment Just noticeable difference Probability of target detection Target mean searching time

Cervical spinal cord injury: tailoring clinical trial endpoints to reflect meaningful functional improvements

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2014年第16期9卷 1493-1497页

作者： Lisa M.bond Lisa McKerracher BioAxone BioSciences Inc.Cambridge MA USA McGill University Department of Neurology and NeurosurgeryMontreal Quebec Canada

Cervical spinal cord injury （SCI） results in partial to full paralysis of the upper and lower extrem- ities. Traditional primary endpoints for acute SCI clinical trials are too broad to assess functional recovery in cervical subjects, raising the possibility of false positive outcomes in trials for cervical SCI. Endpoints focused on the recovery of hand and arm control （e.g., upper extremity motor score, motor level change） show the most potential for use as primary outcomes in upcoming trials of cervical SCI. As the field moves forward, the most reliable way to ensure meaningful clinical testing in cervical subjects may be the development of a composite primary endpoint that measures both neurological recovery and functional improvement.

关键词： spinal cord injury SCI cervical clinical trial endpoint Cethrin UEMS

Recent trends in the use of polyoxometalate-based material for efficient water oxidation

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2011年第12期54卷 1877-1887页

作者： HAN ZhanGang bond Alan M ZHAO Chuan School of Chemistry The University of New South Wales Sydney NSW 2052 Australia School of Chemistry Monash University Clayton Victoria 3800 Australia

Polyoxometalates （POMs）, with their attractive topological and electronic properties, have been demonstrated over the last few decades to be efficient catalysts for many reactions. In a new direction, POMs having a purely inorganic framework are now being explored as efficient catalysts for water oxidation. This review focuses on very recent developments of POM-based catalysts for water oxidation to O2. In the very extensive family of POMs, tetra-core sandwich-type Ru- and Co-containing POM complexes, namely [Ru404（OH）2（H20）4（y-SiW10O36）2]10- and [CO4（H2O）2（a-PWgO34）2]10- exhibit the ability to facilitate water oxidation under electrocatalytic and/or photocatalytic conditions. However, it is concluded that much work still needs to be done to explain the catalytic mechanisms and optimize these catalytic systems. In addition, recent trends in using ionic liquids as media to modify the electrolytic environment and enhance water oxidation are highlighted.

关键词： polyoxometalate water oxidation catalysis electrochemistry photochemistry energy

Diversity of As Metabolism Functional Genes in Pb-Zn Mine Tailings

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2017年第3期27卷 630-637页

作者： LI Xiaofang Philip L.bond Longbin HUANG Centre for Agricultural Resources Research Institute of Genetics and Developmental Biology Chinese Academy of Sciences Centre for Mined Land Rehabilitation Sustainable Minerals Institute The University of Queensland Advanced Water Management Centre The University of Queensland

Microbial activities impact arsenic （As） transformation in mine tailings substantially, yet little is understood on the functional diversity of As metabolism genes. This study explored this issue using a metagenomic approach coupled by a local BLASTN procedure established in our recent studies. An assembled metagenome, recovered from hypersaline and sulfidic mine tailings, was screened for As metabolism genes aioA, arrA, arsC and arsM. This was done using a local BLASTN procedure against databases of the As metabolism genes built in this study. Putative As metabolism genes detected in the assembled metagenome included 11 arsM, 20 arsC and 1 arrA full-length sequences. Together with the rRNA-based phylogenetic profiling results, a picture depicting microbial As cycling in the tailings to the genus level was obtained. It was found that most of the dominant genera in the tailings potentially harboured the genes for As reduction and/or methylation. In particular, a typical pyrite-eater present in the tailings, Thioalkalivibrio sp., was found to harbour not only arsC and arsM, but also arrA. These results highlight the unexpected diversity of As metabolism genes in the tailings, especially considering the extremely low species diversity therein. The microbial As cycling picture established here has potential use for guiding the purposeful manipulation of As biogeochemistry in the railings.

关键词： arsenic cycling arsM local BLASTN procedure metagenomics revegetation Thioalkalivibrio sp.

JMCB Symposium 2019:The Legend of p53 ***

在线全文

学校读者我要写书评

暂无评论

Journal of Molecular Cell Biology 2019年第7期11卷 628-629页

作者： Ping Zhang Suzanne P.Christen Gareth L.bond Ludwig Institute for Cancer Research Nuffield Department of MedicineUniversity of OxfordOxford 0X3 7DQUK The Simons Center for Systems Biology Institute for Advanced StudyPrincetonNJ 08540USA

The exciting symposium hosted by Journal of Molecular Cell Biology (JMCB),with the theme 'The Legend of p53 ***',took place in Hangzhou,China on May 10-12,*** symposium provided the opportunity for delegates in the fields of p53 biology,epigenetics,and cancer research to share scientific updates and to bridge the gap between basic scienee and translational *** delegates also enjoyed celebrations ofthe 40th anniversary ofthe discovery of p53,as well as the 50th anniversary ofthe discovery of RNA polymerases.

关键词： symposium JMCB polymerases

Nanotechnology applications for the therapy of liver fibrosis

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 2014年第23期20卷 7242-7251页

作者： Lydia Giannitrapani Maurizio Soresi Maria Luisa bondì Giuseppe Montalto Melchiorre Cervello Unit of Internal Medicine Biomedical Department of Internal Medicine and Specialties DiBiMISUniversity of Palermo90127 PalermoItaly Institute for Nanostructured Materials Studies National Research Council (CNR)90146 PalermoItaly Institute of Biomedicine and Molecular Immunology "A.Monroy" National Research Council (CNR)90146 PalermoItaly

Chronic liver diseases represent a major global health problem both for their high prevalence worldwide and,in the more advanced stages,for the limited available curative treatment *** fact,when lesions of different etiologies chronically affect the liver,triggering the fibrogenesis mechanisms,damage has already occurred and the progression of fibrosis will have a major clinical impact entailing severe complications,expensive treatments and death in end-stage liver *** significant advances in the understanding of the mechanisms of liver fibrinogenesis,the drugs used in liver fibrosis treatment still have a limited therapeutic *** drugs showing potent antifibrotic activities in vitro often exhibit only minor effects in vivo because insufficient concentrations accumulate around the target cell and adverse effects result as other non-target cells are *** stellate cells play a critical role in liver fibrogenesis,thus they are the target cells of antifibrotic *** application of nanoparticles has emerged as a rapidly evolving area for the safe delivery of various therapeutic agents(including drugs and nucleic acid)in the treatment of various pathologies,including liver *** this review,we give an overview of the various nanotechnology approaches used in the treatment of liver fibrosis.

关键词： Liver fibrosis Nanotechnology Nanoparticles Hepatic stellate cells Antifibrotic drugs Cirrhosis

“Know Diabetes by Heart”: role of adipocytecardiomyocyte communications

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Medical Review 2021年第1期1卷 14-17页

作者： Yajing Wang Wayne bond Lau Xinliang Ma Department of Emergency Medicine Thomas Jefferson UniversityPhiladelphia 19107PAUSA.

Cardiovascular disease is the leading cause of morbidity in patients with diabetes *** 2019,the American Heart Association and the American Diabetes Association(along with industry leaders)launched the groundbreaking collaborative initiative“Know Diabetes by Heart™”to reduce cardiovascular deaths in type 2 diabetic *** molecular basis linking diabetes with cardiovascular complications has not yet been fully *** clinical and experimental studies strongly suggest that adipocyte dysfunction and subsequent pathological communications between adipocyte and cardiomyocytes play important roles in diabetic cardiac *** perspective article will review recent development concerning adipocyte-cardiomyocyte communications,and identify the most critical questions remain to be answered in this filed.

关键词： adipocyte cardiomyocyte diabetes myocardial ischemia.