检索结果-南通市图书馆

QCD sum rule study of J^(P)=1^(±)exotic states with two heavy quarks in the molecular picture

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2024年第6期48卷 31-37页

作者： t.m.Aliev S.Bilmis m.Savcı Department of Physics Middle East Technical UniversityAnkara06800Turkey tUBItAK ULAKBIm Ankara06510Turkey

In this study,the spectroscopic param.t.rs of exotic molecular states composed of mesons containing two heavy quarks(scalar-axial and pseudoscalar-axial meson combinations)are investigated within the QCD sum rules.Our findings reveal that molecular states containing charm quarks do not form bound states,whereas states with b-quarks can form exotic molecular states.this observation has significant implications for understanding the structure of these exotic states.

关键词： QCD sum rules exotic mesons molecular states

Supposition of graphene stacks to estim.t. the contact resistance and conductivity of nanocomposites

在线全文

学校读者我要写书评

暂无评论

Applied m.t.em.t.cs and mechanics(English Edition) 2024年第4期45卷 663-676页

作者： Y.ZARE m.t.mUNIR G.J.WENG K.Y.RHEE Biom.t.rials and tissue Engineering Research Group Department of Interdisciplinary TechnologiesBreast Cancer Research CenterMotamed Cancer InstituteTehran ***Iran College of Engineering and technology American University of the Middle EastEgaila 54200Kuwait Department of mechanical and Aerospace Engineering Rutgers UniversityNew BrunswickNJ 08903U.S.A. Department of mechanical Engineering(BK21 Four) College of EngineeringKyung Hee UniversityYongin 446701Republic of Korea

In this study,the effects of stacked nanosheets and the surrounding interphase zone on the resistance of the contact region between nanosheets and the tunneling conductivity of samples are evaluated with developed equations superior to those previously reported.the contact resistance and nanocomposite conductivity are modeled by several influencing factors,including stack properties,interphase depth,tunneling size,and contact diam.t.r.the developed model's accuracy is verified through numerous experimental measurements.to further validate the models and establish correlations between param.t.rs,the effects of all the variables on contact resistance and nanocomposite conductivity are analyzed.Notably,the contact resistance is primarily dependent on the polymer tunnel resistivity,contact area,and tunneling size.the dimensions of the graphene nanosheets significantly influence the conductivity,which ranges from 0 S/m.t.90 S/m.An increased number of nanosheets in stacks and a larger gap between them enhance the nanocomposite's conductivity.Furthermore,the thicker interphase and smaller tunneling size can lead to higher sample conductivity due to their optimistic effects on the percolation threshold and network efficacy.

关键词： graphene polymer composite stacked nanosheet tunneling conductivity contact resistance interphase

Late Ordovician mass Extinction: Earth, fire and ice

在线全文

学校读者我要写书评

暂无评论

National Science Review 2024年第1期11卷 51-65页

作者： David A.t.Harper Palaeoecosystems Group Department of Earth SciencesDurham University

the Late Ordovician mass Extinction was the earliest of the ‘big’ five extinction events and the earliest to affect the trajectory of m.t.zoan life. two phases have been identified near the start of the Hirnantian period and in the middle. It was a massive taxonomic extinction, a weak phylogenetic extinction and a relatively benign ecological extinction. A rapid cooling, triggering a major ice age that reduced the temperature of surface waters, prom.t.d a drop in sea level of some 100 m and introduced toxic bottom waters onto the shelves. these sym.t.ms of more fundamental planetary processes have been associated with a range of factors with an underlying driver identified as volcanicity. Volcanic eruptions, and other products, may have extended back in time to at least the Sandbian and early Katian, suggesting the extinctions were more protracted and influential than hitherto documented.

关键词： Ordovician LOmE paleoecology palaeobiogeography biotas

Search for production of dark fermion candidates in association with heavy neutral gauge boson decaying to dimuon in proton-proton collisions at√s=8 teV using CmS open data

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics C 2024年第4期48卷 6-13页

作者： Y.mahmoud H.Abdallah m.t.Hussein S.Elgammal Centre for theoretical physics The British University in EgyptEgypt Physics Department Faculty of ScienceCairo UniversityEgypt

In this study,we conducted a search for dark m.t.er using a part of the data recorded by the CmS experiment during run-I of the LHC in 2012 with a center of mass energy of 8 teV and an integrated luminosity of 11.6 fb−1.these data were gathered from.t.e CmS open data.Dark m.t.er,in the framework of the simplified model(mono-Z′),can be produced from proton-proton collisions in association with a new hypothetical gauge boson,Z′.thus,the search was conducted in the dimuon plus large missing transverse momentum channel.One benchmark scenario of mono-Z′,which is known as light vector,was used for interpreting the CmS open data.No evidence of dark m.t.er was observed,and exclusion lim.t. were set on the masses of dark m.t.er and Z′at 95%confidence level.

关键词： dark m.t.er large hadron collider CmS open data search for new physics dark fermion

SmILE soft X-ray Imager flight model CCD370 pre-flight device characterisation

在线全文

学校读者我要写书评

暂无评论

Earth and Planetary Physics 2024年第1期8卷 25-38页

作者： S.Parsons D.J.Hall O.Hetherington t.W.Buggey t.Arnold m.W.J.Hubbard A.Holland Centre for Electronic Imaging the Open UniversityMilton KeynesMK76AAUK

throughout the SmILE mission the satellite will be bombarded by radiation which gradually damages the focal plane devices and degrades their performance.In order to understand the changes of the CCD370s within the soft X-ray Imager,an initial characterisation of the devices has been carried out to give a baseline performance level.three CCDs have been characterised,the two flight devices and the flight spa re.this has been carried out at the Open University in a bespo ke cleanroom measure ment facility.the results show that there is a cluster of bright pixels in the flight spa re which increases in size with tempe rature.However at the nominal ope rating tempe rature(-120℃) it is within the procure ment specifications.Overall,the devices meet the specifications when ope rating at -120℃ in 6 × 6 binned frame transfer science mode.the se rial charge transfer inefficiency degrades with temperature in full frame mode.However any charge losses are recovered when binning/frame transfer is implemented.

关键词： CCD soft X-ray imager characterisation SmILE

management of male obesity-related secondary hypogonadism:A clinical update

在线全文

学校读者我要写书评

暂无评论

World Journal of Experimental medicine 2024年第2期14卷 11-28页

作者： mohan t Shenoy Sunetra mondal Cornelius James Fernandez Joseph m Pappachan Department of Endocrinology Sree Gokulam Medical Collegeand Research FoundationTrivandrum 695607KeralaIndia Department of Endocrinology NRS Medical College and HospitalKolkata 700014West BengalIndia Department of Endocrinology&m.t.bolism Pilgrim HospitalUnited Lincolnshire Hospitals NHS TrustBoston PE219QSUnited Kingdom Department of Endocrinology and m.t.bolism Lancashire Teaching Hospitals NHS TrustPreston PR29HTUnited Kingdom Faculty of Science Manchester Metropolitan UniversityManchester M156BHUnited Kingdom Faculty of Biology Medicine&HealthThe University of ManchesterManchester M139PLUnited Kingdom

the global obesity pandemic has resulted in a rise in the prevalence of male obesity-related secondary hypogonadism(mOSH)with emerging evidence on the role of testosterone therapy.We aim.t. provide an updated and practical approach towards its management.We did a comprehensive literature search across mEDLINE(via Pubmed),Scopus,and Google Scholar databases using the keywords“mOSH”OR“Obesity-related hypogonadism”OR“testosterone replacement therapy”OR“Selective estrogen receptor modulator”OR“SERm”OR“Guidelines on male hypogonadism”as well as a manual search of references within the articles.A narrative review based on available evidence,recommendations and their practical implications was done.Although weight loss is the ideal therapeutic strategy for patients with mOSH,achievement of significant weight reduction is usually difficult with lifestyle changes alone in real-world practice.therefore,androgen administration is often necessary in the management of hypogonadism in patients with mOSH which also improves many other comorbidities related to obesity.However,there is conflicting evidence for the appropriate use of testosterone replacement therapy(tRt),and it can also be associated with complications.this evidence-based review updates the available evidence including the very recently published results of the tRAVERSE trial and provides comprehensive clinical practice pearls for the management of patients with mOSH.Before starting testosterone replacement in functional hypogonadism of obesity,it would be desirable to initiate lifestyle modification to ensure weight reduction.tRt should be coupled with the management of other comorbidities related to obesity in mOSH patients.Balancing the risks and benefits of tRt should be considered in every patient before and during longterm management.

关键词： male obesity-related secondary hypogonadism Androgen therapy testosterone replacement therapy Obesity Cardiovascular benefits

Impact of device resistances in the performance of graphene‑based terahertz photodetectors

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

Frontiers of Optoelectronics 2024年第2期17卷 87-97页

作者： O.Castelló Sofía m.López Baptista K.Watanabe t.taniguchi E.Diez J.E.Velázquez-Pérez Y.m.meziani J.m.Caridad J.A.Delgado-Notario Department of Applied Physics University of Salamanca37008 SalamancaSpain Unidad de Excelencia en Luz y m.t.ria Estructurada(LUmES) University of Salamanca37008 SalamancaSpain Research Center for Electronic and Optical m.t.rials National Institute for Materials Science1-1 NamikiTsukuba 305-0044Japan Research Center for m.t.rials Nanoarchitectonics National Institute for Materials Science1-1 NamikiTsukuba 305-0044Japan Nanotechnology Group USAL-NanolabUniversity of Salamanca37008 SalamancaSpain

In recent years,graphene field-effect-transistors(GFEts)have demonstrated an outstanding potential for terahertz(tHz)photodetection due to their fast response and high-sensitivity.Such features are essential to enable emerging tHz applications,including 6G wireless communications,quantum inform.t.on,bioimaging and security.However,the overall performance of these photodetectors may be utterly compromised by the impact of internal resistances presented in the device,so-called access or parasitic resistances.In this work,we provide a detailed study of the influence of internal device resistances in the photoresponse of high-mobility dual-gate GFEt detectors.Such dual-gate architectures allow us to fine tune(decrease)the internal resistance of the device by an order of magnitude and consequently demonstrate an improved responsivity and noise-equivalent-power values of the photodetector,respectively.Our results can be well understood by a series resistance model,as shown by the excellent agreement found between the experimental data and theoretical calculations.these findings are therefore relevant to understand and improve the overall performance of existing high-mobility graphene photodetectors.

关键词： Graphene tHz Photodetector Field-effect transistor Plasmonic

Aerodynamics of a tandem-Bladed Axial Compressor Rotor under Circumferential Distortion at Different Rotational Speeds

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 thermal Science 2024年第4期33卷 1340-1356页

作者： Am.t.KUmAR Jerry t.JOHN A.m.PRADEEP R.A.D.AKKERmANS Dragan KOZULOVIC Department of Aerospace Engineering Indian Institute of Technology Bombay Department of Autom.t.ve and Aeronautical Engineering Hamburg University of Applied Sciences Institute of Jet Propulsion Bundeswehr University Munich

For most aircraft engines,inflow distortion is inevitable.Inflow distortion is known to degrade the aerodynamic performance and stable operating lim.t. of a compressor.tandem rotor configuration is an arrangement that effectively controls the growth of the boundary layer over the suction surface of the blade.therefore,a higher total pressure rise can be achieved through this unconventional design approach involving the splitting of the blade into forward and aft sections.It is expected that the effect of inlet flow distortion would be more severe for a tandem-rotor design due to the greater flow turning inherent in such designs.However,this aspect needs to be thoroughly examined.the present study discusses the effect of circumferential distortion on the tandem-rotor at different rotational speeds.Full-annulus RANS simulations using ANSYS CFX are used in the present study.the performance of the rotor at a particular flow coefficient and different rotational speeds is compared.the total pressure and efficiency are observed to drop at lower mass flow rates under the influence of circumferential distortion.the loss region in each blade passage is mainly associated with the blade wake,tip leakage vortex,secondary flow,and boundary layer.However,their contribution varies from passage to passage,particularly in the distorted sector.At the lower span,the wake width is found to be higher than that at a higher span.Due to the redistribution of the mass flow,the circumferential extent reduces at a higher span.In the undistorted sector,the strength of the tip leakage vortex is significantly higher at the design rotational speed than at lower speeds.the distortion near the tip region prom.t.s an early vortex breakdown even at the design operating condition.this adversely affects the total pressure,efficiency,and stall margin.Under clean flow conditions,this phenomenon is only observed near the stall point.At the design operating condition,the breakdown of the forward rotor tip leakage vortex is detected in four blade passages

关键词： tandem rotor circumferential distortion loss tip leakage vortex vortex breakdown diffusion factor aerodynamics of compressor blade

the CCD instrument background of the SmILE SXI

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Earth and Planetary Physics 2024年第1期8卷 15-24页

作者： m.W.J.Hubbard O.Hetherington D.J.Hall t.W.Buggey S.Parsons t.Arnold A.Holland C.Pagani S.Sembay Centre for Electronic Imaging The Open UniversityMilton KeynesMK76AAUK X-ray and Observational Astronomy Group Department of Physics&AstronomyUniversity of LeicesterLE17RHUK

the ESA and CAS SmILE mission orbit is highly elliptical and will pass through multiple radiation environments.the Soft X-ray Imager(SXI)instrument aboard has a radiation shutter door designed to close when the surrounding radiation flux is high.the shutter door will close when passing below an altitude threshold to protect against trapped particles in the Earth’s Van Allen Belts.therefore,two radiation environments can be approxim.t.d based on the shutter door position:open and closed.the instrument background for the CCDs(Charge-Coupled Devices)that form.t.e focal plane array of the SXI were evaluated for the two environments.Due to the correlation of the space environment with the solar cycle,the solar minima and maxima,the background was also evaluated at these two extremes.the results demonstrated that the highest instrument background will occur during solar minima due to the main contributing source being Galactic Cosmic Rays(GCRs).It was also found that the open background was highest for solar minima and that the closed background was highest during solar maxima.this is due to the radiation shutter door acting as a scattering centre and the changes in the energy flux distribution of the GCRs between the two solar extremes.

关键词： instrument background X-ray astronomy space radiation