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Probing the Bardeen-Kiselev black hole with the cosmological constant caused by Einstein equations coupled with nonlinear electrodynamics using quasinormal modes and greybody bounds

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Communications in Theoretical Physics 2024年第6期76卷 102-119页

作者： S R Wu B Q wang z W Long College of Physics Guizhou UniversityGuiyang 550025China College Pharmacy Guizhou University of Traditional Chinese MedicineGuiyang 550025China

In this work,we investigate a static and spherically symmetric Bardeen-Kiselev black hole(BH)with the cosmological constant,which is a solution of the Einstein-non-linear Maxwell field *** compute the quasinormal frequencies for the Bardeen-Kiselev BH with the cosmological constant due to electromagnetic and gravitational *** varying the BH parameters,we discuss the behavior of both real and imaginary parts of the BH quasinormal frequencies and compare these frequencies with the Reissner-Nordström-de Sitter BH surrounded by quintessence(RN-dSQ).Interestingly,it is shown that the responses of the Bardeen-Kiselev BH with the cosmological constant and the RN-dSQ under electromagnetic perturbations are different when the charge parameter q,the state parameter w and the normalization factor c are varied;however,for the gravitational perturbations,the responses of the Bardeen-Kiselev BH with the cosmological constant and the RN-dSQ are different only when the charge parameter q is ***,compared with the gravitational perturbations,the electromagnetic perturbations can be used to understand nonlinear and linear electromagnetic fields in curved spacetime *** interesting observation is that,due to the presence of Kiselev quintessence,the electromagnetic perturbations around the Bardeen-Kiselev BH with the cosmological constant damps faster and oscillates slowly;for the gravitational perturbations,the quasinormal mode decays slowly and oscillates *** also study the reflection and transmission coefficients along with the absorption cross section in the Bardeen-Kiselev BH with the cosmological constant;it is shown that the transmission coefficients will increase due to the presence of Kiselev quintessence.

关键词： quasinormal modes greybody factors Bardeen-Kiselev black hole with cosmological constant

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Precipitation of multi-type nano-quasicrystals in a Mg-zn-Y alloy

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Journal of Magnesium and Alloys 2024年第3期12卷 997-1008页

作者： W.z.wang X.z.zhou L.F.zhang H.Q.Ye z.Q.Yang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of ScienceShenyang 110016China Ji Hua Laboratory Foshan 528251China Foshan University Foshan 528231China

Mg-6zn-1Y(at.%)ribbons with strengthening precipitates of multi-type nanoquasicrystals were prepared by melt-spinning followed by aging *** evolution of the rapidly solidified ribbons during isothermal aging was comprehensively studied using various electron microscopy *** new kinds of decagonal quasicrystals were formed in aged ribbons,in addition to precipitation of nanometer icosahedral ***-resolution observations reveal that both decagonal quasicrystals can be modeled by quasiperiodic tiling with decagonal clusters of 2.5 nm in diameter,but overlap of neighboring clusters in both decagonal quasicrystals is different from the Gummelt model observed in other quasicrystals.A shell composed of complex Laves Mg-zn domains was formed surrounding each decagonal quasicrystal precipitate upon prolonged *** addition,all kinds of nanoprecipitates exhibit excellent structure and size stability at 573 *** findings may have implications for not only fundamental studies about quasicrystals,but also microstructural manipulation of high-performance Mg alloys.

关键词： Quasicrystal Mg alloys Rapid solidification Scanning-transmission electron microscopy.

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Flat Band and η-Pairing States in a One-Dimensional MoiréHubbard Model

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Chinese Physics Letters 2024年第4期41卷 69-76页

作者：王冉宋智 College of Physics and Materials Science Tianjin Normal UniversityTianjin 300387China School of Physics Nankai UniversityTianjin 300071China

A Moirésystem is formed when two periodic structures have a slightly mismatched period,resulting in unusual strongly correlated states in the presence of particle-particle *** periodic structures can arise from the intrinsic crystalline order and periodic external *** investigate a one-dimensional Hubbard model with periodic on-site potential of period n_(0),which is commensurate to the lattice *** large n_(0),the exact solution demonstrates that there is a midgap flat band with zero energy in the absence of Hubbard *** Moiréunit cell contributes two zero energy levels to the flat *** the presence of Hubbard interaction,the midgap physics is demonstrated to be well described by a uniform Hubbard chain in which the effective hopping and on-site interaction strength can be controlled by the amplitude and period of the external *** simulations are performed to demonstrate the correlated behaviors in the finite-sized Moiré Hubbard system,including the existence of an η-pairing state and bound pair *** finding provides a method to enhance the correlated effect by a spatially periodic external field.

关键词： oscillation interaction field

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Clinical role of ^(18)F-FDG PET/CT-based simultaneous modulated accelerated radiotherapy treatment planning for locally advanced nasopharyngeal carcinoma

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Oncology and Translational Medicine 2015年第6期1卷 264-270页

作者： Jianshe wang Tianyou Tang Jing Xu Andrew z.wang Liang Li Junnian zheng Longzhen zhang Department of Radiation Oncology The Affiliated Hospital of Xuzhou Medical College Cancer Institute of Xuzhou Medical College Functional Lab Xuzhou Medical College Department of Radiation Oncology The University of North Carolina-Chapel Hill Jiangsu Key Laboratory of Biological Cancer Therapy Xuzhou Medical College

Objective The aim of this study was to compare the long-term local control, overall survival, and late toxicities of positron emission tomography/computed tomography （PET/CT）-guided dose escalation radio- therapy versus conventional radiotherapy in the concurrent chemoradiotherapy treatment of locally ad- vanced nasopharyngeal carcinoma （NPC）. Methods Atotal of 48 patients with stage IIl-IVa NPC were recruited and randomly administered PET/CT- guided dose escalation chemoradiotherapy （group A） or conventional chemoradiotherapy （group B）. The dose-escalation radiotherapy was performed using the simultaneous modulated accelerated radiotherapy technique at prescribed doses of 77 gray （Gy） in 32 fractions （f） to the gross target volume （GTV）： planning target volume （PTV） 1 received 64 Gy/32 f, while PTV2 received 54.4 Gy/32 f. Patients in group B received uniform-dose intensity-modulated radiotherapy, PTV1 received 70 Gy/35 f and PTV2 received 58 Gy/29 f. Concurrent chemotherapy consisted of cisplatin [20 mg/m2 intravenous （IV） on days 1-4] and docetaxel （75 mg/m2 IV on days 1 and 8） administered during treatment weeks 1 and 4. All patients received 2-4 cycles of adjuvant chemotherapy of the same dose and drug regimen. Results The use of fluorine-18-fluorodeoxyglucose （18F-FDG） PET/CT significantly reduced the treat- ment volume delineation of the GTV in 83.3% （20/24） of patients. The 5-year local recurrence-free survival rates of the two groups were 100% and 79.2%, respectively （P = 0.019）. The 5-year disease free survival （DFS） rates were 95.8% and 75.0%, respectively （P = 0.018）. The 5-year local progression-free survival and DFS rates were significantly different. The 5-year overall survival （OS） rates were 95.8% and 79.2%, re- spectively. Differences in OS improvement were insignificant （P = 0.079）. Late toxicities were similar in the two groups. The most common late toxicities of the two arms were grade 1-2 skin dystrophy, xerostomia, subcutaneous fibrosis, and he

关键词： nasopharyngeal carcinoma (NPC) simultaneous modulated accelerated radiotherapy in-tensity-modulated radiotherapy positron emission tomography/computed tomography (PET/CT) fluorine-18-fluorodeoxyglucose (18F-FDG)

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Study on ionospheric disturbance propagation from the high to low latitude with the Digisonde observation

Study on ionospheric disturbance propagation from the high t...

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作者： J.K.Shi z.wang G.zherebtsov A.Stepanov National Space Science Center Institute of Solar-Terrestrial Physics Institute of Cosmophysical Research and Aeronomy

The data from DPS-4 digisonde measurement at Hainan(19.4°N,109.0°E),China,and Yakutsk(62°N,129°E) and zhigansk(66°N,123°E),Russia to study ionospheric SpreadF(SF) during the magnetic storm *** results show that:... 详细信息

关键词： Study on ionospheric disturbance propagation from the high to low latitude with the Digisonde observation storm

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Bright,high-repetition-rate water window soft X-ray source enabled by nonlinear pulse self-compression in an antiresonant hollow-core fibre

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Light(Science & Applications) 2021年第3期10卷 313-319页

作者： M.Gebhardt T.Heuermann R.Klas C.Liu A.Kirsche M.Lenski z.wang C.Gaida J.E.Antonio-Lopez A.Schülzgen R.Amezcua-Correa J.Rothhardt J.Limpert Institute of Applied Physics Abbe Center of PhotonicsFriedrich-Schiller-Universitat JenaAlbert-Einstein-Str.1507745 JenaGermany Helmholtz-Institute Jena Frobelstieg 307743 JenaGermany CREOL College of Optics and PhotonicsUniversity of Central FloridaOrlandoFL 32816USA Fraunhofer Institute for Applied Optics and Precision Engineering Albert-Einstein-Str.707745 JenaGermany Active Fiber Systems GmbH Ernst-Ruska-Ring 1707745 JenaGermany

Bright,coherent soft X-ray radiation is essential to a variety of applications in fundamental research and life *** date,a high photon flux in this spectral region can only be delivered by synchrotrons,free-electron lasers or high-order harmonic generation sources,which are driven by kHz-class repetition rate lasers with very high peak ***,we establish a novel route toward powerful and easy-to-use SXR sources by presenting a compact experimentin which nonlinear pulse self-compression to the few-cycle regime is combined with phase-matched high-orderharmonic generation in a single,helium-illed antiresonant hollow-core *** enables the first 100 kHz-classrepetition rate,table-top soft X-ray source that delivers an application-relevant flux of 2.8×10^6 photon s^-1 eV^-1 around 300 *** fibre integration of temporal pulse self-compression(leading to the formation of the necessarystrong-field waveforms)and pressure-controlled phase matching will allow compact,high-repetition-rate lasertechnology,including commercially available systems,to drive simple and cost-effective,coherent high-flux softX-ray sources.

关键词： pulse repetition fibre

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Numerical Study of Flow Features Around Submerged Circular and Square Piles at Flat and Scoured Beds Using OpenFOAM

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Journal of Ocean University of China 2024年第4期23卷 897-914页

作者： wang Chaolin WU Guoxiang wang Dianhe DU Shengtao zHANG zhiyong JIN Heng zHU David z. LIANG Bingchen Donghai Academy School of Civil&Environmental Engineering and Geography ScienceNingbo UniversityNingbo 315211China Key Laboratory of Estuary and Coast of zhejiang Province and Zhejiang Institute of Hydraulics and EstuaryHangzhou 310020China Shandong Provincial Key Laboratory of Ocean Engineering and College of EngineeringOcean University of ChinaQingdao 266100China Shandong Water Conservancy Vocational College Rizhao 276826China School of Mechanical and Energy Engineering Ningbotech UniversityNingbo 315211China

Elucidating the flow features around piles in local scouring processes is crucial for studies of local scouring mechanisms and scour depth *** study details the flow turbulence characteristics of two submerged piles that are determined by solving the Navier-Stokes equations with the improved delayed detached eddy simulation *** model is verified by comparing experimental and numerical results for hydrodynamic parameters with the literature for both square-crossing piles(SCPs)and circular-crossing piles(CCPs).Original topographies of flat and scoured beds(i.e.,the initial and equilibrium scouring stages)are based on experimental results obtained by the authors in the present *** and CCP flow features in the scouring process are *** results indicate that during the scouring process,the time-averaged drag coefficient and root mean square(rms)of the lift coefficient increase linearly in the CCP test,while the rms of the lift coefficient in the SCP test decreases ***,the minimum pressure coefficient is always located in the upstream corners in the SCP case but moves from 72.5°to 79.5°when the scour hole is completely developed in the CCP *** flow behind the pile,which is generated by separated boundary layers above the top face of the pile,can reach the sand bed and turn the separated shear layers into patches of small vortices in the near-wake ***,the high shear stress zones are mainly at the scour edges under scoured-bed conditions.

关键词： flat bed scoured bed local scour OpenFOAM bed shear stress

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Stability Investigation and Improvement for DC Cascade Systems with Simplified Impedance-based Stability Criterion

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1044-1052页

作者： Junbin Fang zhikang Shuai Yang Li zhibing wang Xiangyang Wu Xia Shen z.John Shen College of Electrical and Information Engineering Hunan UniversityChangsha 410082China Renewable Energy Department of China Electric Power Research Institute Beijing 100192China Department of Electrical and Computer Engineering Illinois Institute of TechnologyChicagoIL 60616USA IEEE

In DC distributed power systems(DPSs),the complex impedance interactions possibly lead to DC bus voltage oscillation or *** previous research,the stability analysis of DPSs is implemented based on mathematical analysis in control *** specific mechanisms of the instability of the cascade system have not been intuitively *** this paper,the stability analysis of DPSs based on the traditional Nyquist criterion is simplified to the resonance analysis of the seriesconnected port impedance(z=R+jX)of source and load *** reveals that the essential reason for impedance instability of a DC cascade system is that the negative damping characteristic(Rzero-crossing *** simplified stability criterion for DC cascade systems can be concluded as:in the negative damping frequency ranges(Rzero-crossing point of the reactance component(i.e.,X=0).According to the proposed stability criterion,the oscillation modes of cascade systems are classified.A typical one is the internal impedance instability excited by the negative damping,and the other one is that the external disturbance amplified by negativity in a low stability ***,the impedance reshaping method for stability improvement of the system can be further *** validity of the simplified criterion is verified theoretically and experimentally by a positive damping reshaping method.

关键词： DC cascaded system,impedance model impedance reconstruction stability criterion

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看美国卒中治疗改进措施,思考中国卒中医疗挑战

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中国卒中杂志 2012年第8期7卷 601-605页

作者： David z.wang INI Stroke Network OSF Healthcare SystemUniversity of Illinois College of Medicine-PeoriaPeoria.IL 61604USA

在美国，卒中医疗质量改进在所有的医疗卫生改进措施中起步最早。卒中是成人致残的第一大疾病，是成人死亡的第三大疾病，花费已超过5604L美元，常常是诊断相关组（diagnosisrelatedgrouD，DRG）入院的第5位原因。卒中医疗质量改进始于2... 详细信息

在美国，卒中医疗质量改进在所有的医疗卫生改进措施中起步最早。卒中是成人致残的第一大疾病，是成人死亡的第三大疾病，花费已超过5604L美元，常常是诊断相关组（diagnosisrelatedgrouD，DRG）入院的第5位原因。卒中医疗质量改进始于20世纪90年代末期。

关键词：卒中卫生保健质量优质医疗质量绩效

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基于负载高峰特征的虚拟机放置算法

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软件学报 2016年第7期27卷 1876-1887页

作者：徐思尧林伟伟王子骏华南理工大学计算机科学与工程学院广东广州510006 School of Computing Clemson University

提出了一种基于虚拟机负载高峰特征的虚拟机放置策略,通过更好地复用物理主机资源来实现资源共享,从而提高资源利用率.在云环境下,当多个虚拟机的负载高峰出现在相同的时间段内时,非高峰时段的资源利用率就会明显偏低;相反,多个虚拟机... 详细信息

提出了一种基于虚拟机负载高峰特征的虚拟机放置策略,通过更好地复用物理主机资源来实现资源共享,从而提高资源利用率.在云环境下,当多个虚拟机的负载高峰出现在相同的时间段内时,非高峰时段的资源利用率就会明显偏低;相反,多个虚拟机只要负载高峰能错开在不同的时间,闲置的资源就能更充分地被利用.由于应用的负载通常具有一定的周期性,因此,可以利用虚拟机负载的历史数据作为分析的依据.基于虚拟机的负载高峰特征对虚拟机负载进行建模,建立虚拟机负载之间的相似度矩阵来实现虚拟机联合放置.使用Cloud Sim模拟实现了所提出的算法,并与基于相关系数的放置算法、随机放置算法进行了比较.实验结果表明：所提算法在平均CPU利用率上有8.9%~12.4%的提高,主机使用量有8.2%~11.0%的节省.

关键词：高峰特征相似度资源复用虚拟机放置云计算

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