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New thermal optimization scheme of power module in solid-state amplifier

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Nuclear Science and Techniques 2019年第4期30卷 143-149页

作者： Lie-Peng Sun Zhen-Yu Yuan Cheng Zhang Xian-bo Xu Jun-Gang Miao Jian-Hua Zhang long-bo shi Yuan He Beijing BBEF Science and Technology Co. Ltd. Institute of Modern Physics Chinese Academy of Sciences Beihang University

The new 1 kW power module for ADS project needs the optimization of cooling design including water flow and tunnel layout, and the water flow of three tons per hour was chosen to be a goal for a 20 kW power *** to analysis from the insertion and integrated loss, about 24 modules were integrated into the rated power. Thus, every module has a cooling flow of 2.1 L/min for RF heat load and power supply loss, which is very hard to achieve if no special consideration and techniques. A new thermal simulation method was introduced for thermal analysis of cooling plate through CST multi-physics suite,especially for temperature of power LDMOS *** specific measures carried out for the higher heat transfer were also presented in this paper.

关键词： RF system Solid-state amplifier Power module Heat transfer coefficient

Precise calibration of cavity forward and reflected signals using low-level radio-frequency system

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Nuclear Science and Techniques 2022年第1期33卷 35-43页

作者： Jin-Ying Ma Feng Qiu long-bo shi Zheng-long Zhu Tian-Cai Jiang Zong-Heng Xue Ke-An Jin Qi Chen Cheng-Ye Xu Xing-Hao Ding Zheng Gao Lie-Peng Sun Gui-Rong Huang Yuan He Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China

Precise measurements of the cavity forward(Vf)and reflected signals(Vr)are essential for characterizing other key parameters such as the cavity detuning and forward *** practice,it is challenging to measure V_(f) and V_(r) precisely because of cross talk between the forward and reflected channels(e.g.,coupling between the cavity reflected and forward signals in a directional coupler with limited directivity).For DESY,a method based on the cavity differential equation was proposed to precisely calibrate the actual V_(f) and V_(r).In this study,we verified the validity and practicability of this approach for the Chinese ADS front-end demo superconducting linac(CAFe)facility at the Institute of Modern Physics and a compact energy recovery linac(cERL)test machine at *** the CAFe facility,we successfully calibrated the actual V_(f) signal using this *** result demonstrated that the directivity of directional couplers might seriously affect the accuracy of V_(f) *** the cERL facility,we calibrated the Lorentz force detuning(LFD)using the actual *** study confirmed that the precise calibration of V_(f) significantly improves the accuracy of the cavity LFD measurement.

关键词： Forward and reflected signals Measurement Calibration

Almost Periodic Type Group Actions on Compact Quantum Metric Spaces

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Acta Mathematica Sinica,English Series 2024年第2期40卷 568-594页

作者： bo Tao long Wei WU College of Mathematics MIIT Key Laboratory of Mathematical Modelling and High Performance Computing of Air VehiclesNanjing University of Aeronautics and AstronauticsNanjing 211106P.R.China School of Mathematical Sciences Shanghai Key Laboratory of Pure Mathematics and Mathematical PracticeEast China Normal UniversityShanghai 200241P.R.China

A compact quantum metric space is a complete order unit space A endowed with a Lipnorm *** give some characterizations of almost periodic type group actions on a compact quantum metric space(A,L)by means of several kinds of subsets of A,its induced equicontinuous actions on several important subsets of the dual Banach space A*,and the Lip-norm L with its induced metric space structures on the state space S(A)of A.

关键词： Lip-norm compact quantum metric space Lipschitz isomorphism almost periodicity Arzela-Ascoli theorem metric set

Black hole evaporation and its remnants with the generalized uncertainty principle including a linear term

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Communications in Theoretical Physics 2024年第2期76卷 125-136页

作者： bo Yu Zheng-wen long College of Physics Guizhou UniversityGuiyang550025China

In recent years,researchers have investigated the evaporation of Schwarzschild black holes using various forms of the generalized uncertainty principle(GUP),metric quantum correction,and noncommutative geometry,***,there are differences between the GUP correction and the other two methods in terms of describing the later stages of black hole ***,some studies argue that the GUP with a negative parameter cannot effectively correct black hole evaporation,while others contend that the positivity or negativity of the GUP parameters should not affect the correction *** the above into consideration,we reconsider black hole evaporation with the generalized uncertainty principle including a linear term(LGUP),and examine the case of negative *** results indicate that the evaporation behavior of both Schwarzschild black holes and Reissner–Nordstr?m black holes,under LGUP correction,is consistent with the results of metric quantum correction and non-commutative ***,the negative parameter LGUP can also effectively correct for black hole evaporation.

关键词： black hole evaporation generalized uncertainty principle negative parameter

Electronic and Thermoelectric Properties in SnS-Nanoribbon-Based Heterojunctions

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Chinese Physics Letters 2024年第9期41卷 63-68页

作者： Kai-bo Zhang shi-Hua Tan Xiao-Fang Peng Meng-Qiu long Hunan Province Key Laboratory of Materials Surface or Interface Science and Technology Central South University of Forestry and TechnologyChangsha 410004China School of Physics and Electronics Central South UniversityChangsha 410083China

As an earth-abundant and environmentally friendly material,tin sulfide(SnS)is not only a high-performance photovoltaic material,but also a new promising thermoelectric *** extensive research on the thermoelectric properties of this material in recent years,the room-temperature thermoelectric figure of merit(ZT)of SnS has not been broke through 2[2022 *** Mater.651143].In this work,based on a combination of density functional theory and non-equilibrium Green’s function method,the electronic and thermoelectric properties in SnS-nanoribbon-based heterojunctions are *** results show that although SnS nanoribbons(SNSNRs)with zigzag edges(ZSNSNRs)and armchair edges(ASNSNRs)both have semiconductor properties,the bandgaps of ASNSNRs are much wider than those of ZSNSNRs,which induces much wider conductance gaps of𝑁-ASNSNR(N𝑁is the number of tin-sulfide lines across the ribbon width)).In the positive energy region,the ZT peaks of𝐿L-SNS-Au are much larger than those of𝐿L-SNS-GNR(L𝐿represents the number of longitudinal repeating units of SNSNR in the scattering region).While in the positive energy region,the ZT peaks of𝐿-SNSGNR are larger than those of𝐿-*** calculations reveal that the figure of merit will be over 3.7 in L-SNS-Au and 2.2 in𝐿L-SNS-GNR at room temperature,and over 4 in𝐿L-SNS-Au and 2.6 in𝐿L-SNS-GNR at 500 K.

关键词： material. sulfide ribbon

Measurement of the cavity-loaded quality factor in superconducting radio-frequency systems with mismatched source impedance

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Nuclear Science and Techniques 2023年第8期34卷 12-23页

作者： Jin-Ying Ma Cheng-Ye Xu An-Dong Wu Guo-Dong Jiang Yue Tao Zong-Heng Xue long-bo shi Tian-Cai Jiang Zheng-long Zhu Zi-Qin Yang Zheng Gao Lie-Peng Sun Gui-Rong Huang Feng Qiu Yuan He Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China

The accurate measurement of parameters such as the cavity-loaded quality factor(Q_(L))and half bandwidth(f_(0.5))is essential for monitoring the performance of superconducting radio-frequency ***,the conventional"field decay method"employed to calibrate these values requires the cavity to satisfy a"zero-input"*** can be challenging when the source impedance is mismatched and produce nonzero forward signals(V_(f))that significantly affect the measurement *** address this limitation,we developed a modified version of the"field decay method"based on the cavity differential *** proposed approach enables the precise calibration of f_(0.5) even under mismatch *** tested the proposed approach on the SRF cavities of the Chinese Accelerator-Driven System Front-End Demo Superconducting Linac and compared the results with those obtained from a network *** two sets of results were consistent,indicating the usefulness of the proposed approach.

关键词： Loaded quality factor Field decay method Superconducting cavity Mismatch Calibration Cavity differential equation Measurement Accelerator-driven system

Effects of rafting on the meso deformation and fracture behaviour of a Ni-based single crystal superalloy at room temperature: In-situ observation and simulation

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Science China(Technological Sciences) 2024年第7期67卷 2133-2146页

作者： TAN long YANG XiaoGuang shi DuoQi FAN YongSheng shi Yi School of Energy and Power Engineering Beihang UniversityBeijing 102206China Research Institute of Aero-Engine Beihang UniversityBeijing 102206China National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics Beihang UniversityBeijing 102206China School of Materials Science&Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Microstructural rafting of Ni-based single-crystal(SC) superalloys is inevitable at elevated temperatures during long-term service with mechanical loading, which significantly affects the mechanical behaviour of the material. In this study, the effects of rafting on the mesodeformation and fracture behaviour of a Ni-based SC superalloy under cyclic and tensile loads were investigated using in situ scanning electron microscopy(SEM), digital image correlation(DIC), and crystal plasticity finite element method(CP-FEM) simulations. The results indicated that the tensile strength decreased significantly in the rafted specimens. In the cyclic tests, both the virgin and rafted specimens showed an increase in the maximum shear strain with cycle number. The interaction of cross-slip bands was captured by in situ SEM-DIC around the micro-notch of the virgin specimens during the tensile test, while a more homogeneous local deformation field was observed in the rafting specimens. In addition,the fracture behaviour was strongly influenced by the rafting morphology. The crack exhibited instantaneous and long-range fracture features along the octahedral plane as it propagated in the rafting specimen, whereas it deflected over a short distance between the crystallographic planes at an early stage in the virgin specimen, which is consistent with the CP-FEM ***, the CP-FEM results for the crack initiation direction on(111) dominant slip plane were consistent with the in situ SEM observations.

关键词： in-situ SEM-DIC Ni-based SC superalloys microstructural rafting deformation crack path CP-FEM

Structure engineering of cathode host materials for Li-S batteries

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Rare Metals 2024年第4期43卷 1370-1389页

作者： Jia-Jun long Hua Yu Wen-bo Liu School of New Energy and Materials Southwest Petroleum UniversityChengdu610500China School of Mechanical Engineering Sichuan UniversityChengdu610065China

Although lithium-sulfur batteries are one of the favorable candidates for next-generation energy storage devices,a few key challenges that have not been addressed have limited its *** challenges include lithium dendrite growth in the anode side,volume change of the active material,poor electrical conductivity,dissolution and migration of poly sulfides,and slow rate of solid-state reactions in the cathode *** the electrochemical performance of lithium-sulfur batteries is greatly affected by the design of the cathode host material,it has also been widely discussed in addressing the abovementioned *** this paper,three design ideas of cathode host materials in terms of microstructure,crystal structure and electronic structure are introduced and ***,the current progress of these three structural design strategies and their effects on the electrochemical performance of lithium-sulfur batteries are discussed in ***,future directions in the structural design of cathode materials for lithium-sulfur batteries are discussed and further perspectives are provided.

关键词： Lithium-sulfur batteries Structure engineering Cathode Host materials

Pressure transient characteristics of non-uniform conductivity fractured wells in viscoelasticity polymer flooding based on oil-water two-phase flow

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Petroleum Science 2024年第1期21卷 343-351页

作者： Yang Wang Jia Zhang shi-long Yang Ze-Xuan Xu shi-Qing Cheng National Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing102249China

Polymer flooding in fractured wells has been extensively applied in oilfields to enhance oil *** contrast to water,polymer solution exhibits non-Newtonian and nonlinear behavior such as effects of shear thinning and shear thickening,polymer convection,diffusion,adsorption retention,inaccessible pore volume and reduced effective ***,the flux density and fracture conductivity along the hydraulic fracture are generally non-uniform due to the effects of pressure distribution,formation damage,and proppant *** this paper,we present an oil-water two-phase flow model that captures these complex non-Newtonian and nonlinear behavior,and non-uniform fracture characteristics in fractured polymer *** hydraulic fracture is firstly divided into two parts:high-conductivity fracture near the wellbore and low-conductivity fracture in the far-wellbore section.A hybrid grid system,including perpendicular bisection(PEBI)and Cartesian grid,is applied to discrete the partial differential flow equations,and the local grid refinement method is applied in the near-wellbore region to accurately calculate the pressure distribution and shear rate of polymer *** combination of polymer behavior characterizations and numerical flow simulations are applied,resulting in the calculation for the distribution of water saturation,polymer concentration and reservoir *** with the polymer flooding well with uniform fracture conductivity,this non-uniform fracture conductivity model exhibits the larger pressure difference,and the shorter bilinear flow period due to the decrease of fracture flow ability in the far-wellbore *** field case of the fall-off test demonstrates that the proposed method characterizes fracture characteristics more accurately,and yields fracture half-lengths that better match engineering reality,enabling a quantitative segmented characterization of the near-wellbore section with high fracture conductivity and th

关键词： Polymer flooding Non-Newtonian fluid Non-uniform fracture conductivity Two-phase flow Pressure transient analysis