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Multiple branches coupling property and design of PRHRs

Multiple branches coupling property and design of PRHRs

2018 Transactions of the American Nuclear Society, ANS 2018 and Embedded Topical Meeting Nuclear Fuels and Structural Materials

作者： Zhuohua, Zhang Xu, Ran Feng, Li Lin, Xian Ke, Zhou Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

Nuclear reactor applied on ship or floating platform recommend miniaturization and optimization of PRHRs. Due to much larger volume and heat transfer area in PRHRs heat exchanger, miniaturization and design of PRHRs need consider many constraints such as volume and systems configuration in containment. In normal reactor design such constraints are not so rigorous, but in reactor design for floating platform it takes significant difficulties. A multiple branches coupling system is constructed in the paper which describes the actual relationship between PRHRs and other systems or equipment, and by combining temperature distribution in heat exchanger and conservation equations of coupling system, the design parameters set satisfied design requirement can be calculated and optimization of design can be completed by programming solving method. Copyright © 2018 AMERICAN NUCLEAR SOCIETY, INCORPORATED, LA GRANGE PARK , ILLINOIS 60526Printed in USA.

关键词： Heat transfer

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China's greenhouse gas budget during 2000-2023

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National science Review 2025年第4期 24-36页

作者： Wenping Yuan Minqi Liang Yuanyi Gao Ling Huang Li Dan Hongtao Duan Songbai Hong Fei Jiang Weimin Ju Tingting Li Ziyang Lou Shilong Luan Xiao Lu Zhangcai Qin Lishan Ran Lulu Shen Fei Teng Xiangjun Tian Yilong Wang Jing Wei Jiangzhou Xia Xiaosheng Xia Lijun Yu Xu Yue Haicheng Zhang Wen Zhang Yuzhong Zhang Xu Zhao Qiuan Zhu Shilong Piao Xuhui Wang Institute of Carbon Neutrality Sino-French Institute for Earth System Science College of Urban and Environmental Sciences Peking University School of Atmospheric Sciences Guangdong Province Data Center of Terrestrial and Marine Ecosystems Carbon Cycle Sun Yat-sen University Key Laboratory of Regional Climate-Environment for Temperate East Asia Institute of Atmospheric PhysicsChinese Academy of Sciences Key Laboratory of Lake and Watershed Science for Water Security Nanjing Institute of Geography and LimnologyChinese Academy of Sciences State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of Sciences School of Urban Planning and Design Shenzhen Graduate School Peking University Frontiers Science Center for Critical Earth Material Cycling Nanjing University Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology International Institute for Earth System Science Nanjing University Key Laboratory of Atmospheric Environment and Extreme Meteorology Institute of Atmospheric PhysicsChinese Academy of Sciences Shanghai Engineering Research Center of Solid Waste Treatment and Resource Recovery School of Environmental Science & Engineering Shanghai Jiao Tong University Department of Geography The University of Hong Kong Department of Atmospheric and Oceanic Sciences School of PhysicsPeking University Institute of Energy Environment and Economy Tsinghua University State Key Laboratory of Tibetan Plateau Earth System Resources and Environment (TPESRE)Institute of Tibetan Plateau ResearchChinese Academy of Sciences Tianjin Key Laboratory of Water Resources and Environment Tianjin Normal University State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC) Institute of Atmospheric PhysicsChinese Academy of Sciences Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Collaborative Innovation Center of Atmospheric Environment and Equipment Technology School of

National greenhouse gas（GHG） budget,including CO2,CH4and N2O has increasingly become a topic of concern in international climate *** is paying increasing attention to reducing GHG emissions and increasing land sinks to effectively mitigate climate *** estimates of GHG fluxes are crucial for monitoring progress toward mitigating GHG emissions in *** study used comprehensive methods,including emission factor methods,process-based models,atmospheric inversions,and data-driven models,to estimate the long-term trends of GHG sources and sinks from all anthropogenic and natural sectors in China's mainland during 2000-2023,and produced an up-to-date China GHG Budget dataset（CNGHG）.The total gross emissions of the three GHGs show a 3-fold increase from 5.0（95% CI:4.9-5.1） Gt CO2-eq yr-1（in 2000） to 14.3（95% CI:13.8-14.8） Gt CO2-eqyr-1（in2023）.CO2emissions represented 81.8% of the GHG emissions in 2023,while 12.7% and 5.5% were for CH4and N2O,*** the largest CO2source,the energy sector contributed 87.4% *** contrast,the agriculture,forestry and other land use sector was the largest sector of CH4and N2O,representing 50.1% and 6 6.3% emissions,***,China's terrestrial ecosystems serve as a net CO2sink(1.0 Gt CO2yr-1,9596 CI:0.2-1.9 Gt CO2yr-1) during 2012 to 2021,equivalent to an average of 14.3% of fossil *** GHG emission estimates showed a general consistency with national GHG inventories,with gridded and sector-specific estimates of GHG fluxes over China,providing the basis for curtailing GHG emissions for each region and sector.

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Investigation of installation effect of jet noise from turbofan engines 48

Investigation of installation effect of jet noise from turbo...

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48th International Congress and Exhibition on Noise Control Engineering, INTER-NOISE 2019 MADRID

作者： Zhang, Yingzhe Lin, Dakai Yang, Zhigang Lee, Incheol Beijing Aeronautical Science and Technology Research Institute of COMAC Beijing Key Laboratory of Simulation Technology for Civil Aircraft Design China North of Future Science Park Changping District Beijing102211 China

ISBN: (纸本)9788487985317

To quantitatively investigate the impact of installation on jet noise from modern high bypass ratio (BPR) turbofan engines, a model-scale noise experiment with a jet propulsion system and a realistic fuselage model was conducted in the anechoic wind tunnel of ONERA, CEPRA 19. Two area ratios (an area of the secondary nozzle over an area of the primary nozzle), 5 and 7, and various airframe configurations such as positions relative to the jet nozzle position and flap angles, were considered. The followings were investigated using the acoustic data acquired from the experiment: (1) impact of the presence of the airframe;(2) impact of flap angles;(3) impact of jet nozzle position relative to the wing;and (4) flight effect. Based on the observation, it could be concluded that the frequency region can be divided into two parts: the low frequencies (= 1.5 kHz) and high frequencies (> 1.5 kHz). It seems that the interaction between the jet and the pressure side of the wing contributes the noise at the low frequencies and the interaction between the jet and the flap tip contributes the noise at the high frequencies. © INTER-NOISE 2019 MADRID - 48th International Congress and Exhibition on Noise Control Engineering. All Rights Reserved.

关键词： Jet flaps

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Negative thermal expansion of the stars of David in a 1T−NbSe2 monolayer at about 50 K

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Physical Review B 2023年第21期108卷 214103-214103页

作者： Li Cheng Chen Liang Xiaolong Zou Zheng Liu Jian Wu Shunhong Zhang Shuang Qiao Shenzhen Geim Graphene Center (SGC) Tsinghua-Berkeley Shenzhen Institute (TBSI) and Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen 518055 People's Republic of China Institute for Advanced Study Tsinghua University Beijing 100084 People's Republic of China State Key Laboratory of Low Dimensional Quantum Physics Department of Physics Tsinghua University Beijing 100084 People's Republic of China Frontier Science Center for Quantum Information Beijing 100084 People's Republic of China International Center for Quantum Design of Functional Materials (ICQD) University of Science and Technology of China Hefei 230026 Anhui People's Republic of China Department of Physics Capital Normal University Beijing 100048 People's Republic of China Beijing Computational Science Research Center Beijing 100193 People's Republic of China

1T−NbSe2 is a d1 transition metal dichalcogenide, featuring a low-T 13×13 commensurate charge-density-wave (CCDW) phase with the formation of a star of David (SD) pattern. Here, we investigate the temperature dependence of the lattice and electronic structures of the 1T−NbSe2 monolayer using ab initio molecular dynamics simulations, which predicts that the CCDW phase transition can persist up to 350 K. Before melting, an unprecedented enhancement of CCDW order is revealed at ∼50 K, characterized by two order parameters which respectively indicate the in-plane negative thermal expansion and out-of-plane buckling of the SDs. Such lattice distortion takes place in each SD individually via a detailed balance kinetic process, and the induced sharp variation of the charge gap size and the local density of states are consistent with recent scanning tunneling microscopy observations. This unique phenomenon, which is absent in the more extensively studied d1 transition metal dichalcogenide 1T−TaS2, is explained by the delicate competition between lattice energy and entropy.

关键词： Charge density waves Entropy First-principles calculations Phase transitions Temperature Transition metal dichalcogenides Molecular dynamics

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Local Disorder-Induced Elevation of Intrinsic Anomalous Hall Conductance in an Electron-Doped Magnetic Weyl Semimetal

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Physical Review Letters 2020年第8期125卷 086602-086602页

作者： Jianlei Shen Qiushi Yao Qingqi Zeng Hongyi Sun Xuekui Xi Guangheng Wu Wenhong Wang Baogen Shen Qihang Liu Enke Liu State Key Laboratory for Magnetism Institute of Physics Chinese Academy of Sciences Beijing 100190 China School of Physical Sciences University of Chinese Academy of Sciences Beijing 100049 China Shenzhen Institute for Quantum Science and Technology and Department of Physics Southern University of Science and Technology Shenzhen 518055 China Songshan Lake Materials Laboratory Dongguan Guangdong 523808 China Institute of Rare Earths Chinese Academy of Sciences Jiangxi 341000 China Guangdong Provincial Key Laboratory for Computational Science and Material Design Southern University of Science and Technology Shenzhen 518055 China Shenzhen Key Laboratory of for Advanced Quantum Functional Materials and Devices Southern University of Science and Technology Shenzhen 518055 China

Topological materials are expected to show distinct transport signatures owing to their unique band-inversion characteristic and band-crossing points. However, the intentional modulation of such topological responses through experimentally feasible means has yet to be explored in depth. Here, an unusual elevation of the anomalous Hall effect (AHE) is obtained in electron (Ni)-doped magnetic Weyl semimetals Co3−xNixSn2S2, showing peak values in the anomalous Hall-conductivity, Hall-angle, and Hall-factor at a relatively low doping level of x=0.11. The separation of intrinsic and extrinsic contributions using the TYJ scaling model indicates that such a significant enhancement is dominated by the intrinsic mechanism of the electronic Berry curvature. Theoretical calculations reveal that compared with the Fermi-level shifting from electron filling, a usually overlooked effect of doping, that is, local disorder, imposes a striking effect on broadening of the bands and narrowing of the inverted gap, thus resulting in an elevation of the integrated Berry curvature. Our results not only realize an enhancement of the AHE in a magnetic Weyl semimetal, but also provide a practical design principle for modulating the bands and transport properties in topological materials by exploiting the local disorder effect from doping.

关键词： Anomalous Hall effect Dopants Topological materials Transport phenomena Weyl semimetal Crystal growth Density functional theory Magnetization measurements Resistivity measurements

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Normalization of noise spectra of a single-stream jet from two model-scale tests 48

Normalization of noise spectra of a single-stream jet from t...

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48th International Congress and Exhibition on Noise Control Engineering, INTER-NOISE 2019 MADRID

作者： Lin, Dakai Zhang, Yingzhe Yang, Zhigang Lee, Incheol Beijing Aeronautical Science and Technology Research Institute of COMAC Beijing Key Laboratory of Simulation Technology for Civil Aircraft Design China North of Future Science Park Changping District Beijing102211 China

ISBN: (纸本)9788487985317

For the identification of the noise characteristics of a single-stream jet, two model-scale experiments were conducted. The first experiment was carried out at the anechoic chamber of Beijing University of Aeronautics and Astronautics in China and the second one at the anechoic wind tunnel of ONERA in France. In each experiment, spectra were obtained for various nozzle temperature ratios and nozzle pressure ratios. At forward-to-mid angles, the shape of the normalized spectra is consistent, and the level of the normalized spectra moderately changes. At very aft angles, a large scatter at the higher Strouhal numbers less than 0.5 was observed. This means that one velocity exponent could be used for the normalization of spectra at each of forward-to-mid angles and two velocity exponents may need to be introduced for the normalization of spectra at each of aft angles at a given NTR. The velocity exponent which is a critical factor for the normalization of spectra is calculated and compared to other results as well. For unheated jets, the absolute value of the present velocity exponent is off from other results with a similar overall trend whereas, for heated jets, the present velocity exponent is close to other results. © INTER-NOISE 2019 MADRID - 48th International Congress and Exhibition on Noise Control Engineering. All Rights Reserved.

关键词： Velocity

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A Novel Methodology for Calculating Crack Opening Stress under Tension-Compression Cyclic Load

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Advances in Materials science and Engineering 2021年第1期2021卷

作者： Zhang, Lin Wei, Xiaohui Key Lab. of Fundamental Science for National Defense-Advanced Design Technology of Flight Vehicle Nanjing University of Aeronautics and Astronautics Jiangsu Nanjing210016 China State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and Astronautics Jiangsu Nanjing210016 China

Crack closure model has been used in several applications on the prediction of fatigue crack growth life, with expression of crack opening stress often serving as milestones. A typical difficulty in calculating the crack opening stress is the phenomenon of crack closure caused by the compressive load effect. Compressive load effect, resulting in the change of residual stress status at the unloading stage and the decrease of crack opening stress, is a long-term challenge for predicting fatigue crack growth life. We propose the expression of crack opening stress to predict fatigue crack growth life based on the analysis of compact tensile specimen with elastoplastic element method. It combines the characteristics of material and load to deal with the phenomenon of crack closure and uses stress ratio and normalized maximum applied load variable to construct the expression of crack opening stress. In the study of tensile-compression fatigue crack growth experiments, the proposed expression is proved to improve, by comparative analysis, the predictive ability on the whole range of experiment data. The novel expression is accurate and simple. Consequently, it is conducive to calculate the crack opening stress under tension-compression load. © 2021 Lin Zhang and Xiaohui Wei.

关键词： Crack closure

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Electromagnetic Pulse Coupling Effect Analysis for Outboard Engine System of Vehicle

Electromagnetic Pulse Coupling Effect Analysis for Outboard ...

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IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications (IMWS-AMP)

作者： Longying Guo Long Xiao Junfeng Chen Meng Yang Jingxian Yang Science and Technology on Electronmagnetic Compatibility Laboratory China Ship Development and Design Center Wuhan P. R. China

ISBN: (数字)9781728160641

ISBN: (纸本)9781728160658

The outboard engine is induced a back door coupling effect under the excitation of electromagnetic pulse (EMP). There are three electromagnetic effects, including the induced voltage, resonance and thermal effects, interfere with electronic control unit (ECU) of the outboard engine's electronic fuel injection system and prevent it from firing normal. The electromagnetic coupling effect is simulated with full wave method and the corresponding effect tests are carried out. Based on the actual structure of ECU inside the outboard engine, a principled electromagnetic model is established. By full using of finite difference time domain (FDTD) [1]-[2], we can pick up the law of inducing electric field of ECU varying with the incidence angles and polarization directions. And a EMP test system, including a EMP transmitting unit, a field strength monitoring and an independent power supply, is constructed accurately. In our test, the pulsed inducing signals in fuel injection are the main reason for outboard engine breakdown.

关键词： Engines Couplings Electric fields Fuels Probes Radiation effects

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Recent Progress in Metasurfaces: An Introductory Note from Fundamentals and design Methods to Applications

World Scientific Annual Review of Functional Materials

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World Scientific Annual Review of Functional Materials 2024年第2期wsarfm卷

作者： Wei Chen Jiaqing Shen Yujie Ke Yuwei Hu Lin Wu Jinfeng Zhu Zhaogang Dong Institute of Electromagnetics and Acoustics and Key Laboratory of Electromagnetic Wave Science and Detection Technology Xiamen University Xiamen Fujian 361005 P. R. China Institute of Materials Research and Engineering (IMRE) Agency for Science Technology and Research (A*STAR) 2 Fusionopolis Way Innovis #08-03 Singapore 138634 Singapore Science Mathematics and Technology (SMT) Singapore University of Technology and Design (SUTD) 8 Somapah Road Singapore 487372 Singapore Institute of High Performance Computing A*STAR (Agency for Science Technology and Research) 1 Fusionopolis Way No. 16-16 Connexis Singapore 138632 Singapore Department of Materials Science and Engineering National University of Singapore 9 Engineering Drive 1 Singapore 117575 Singapore

Metasurfaces refer to the sub-wavelength nanostructures that are capable of manipulating the amplitude, phase, polarization, and other characteristics of light, to enable diverse applications across the ultraviolet, visible, infrared, and terahertz spectra. In this review paper, we aim to provide an introductory note on metasurfaces, from fundamentals and design methods to applications, such as biosensing, environmental monitoring, metalenses, optical cloaking, electromagnetic scattering, structural color, miniaturized devices, and others. Moreover, we also identify the key challenges and limitations of metasurfaces, such as fabrication, integration, optimization, tuning, signal processing, and analysis, and suggest possible directions and solutions for future research. At last, we envision several emerging and promising trends for metasurfaces, such as new materials and structures, new phenomena and mechanisms, machine learning, and artificial intelligence techniques. The review is expected to inspire future development in this exciting and rapidly evolving field of metasurface devices.

关键词： Metamaterial metasurface deep learning nanophotonics

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Study on Impact Damage Characteristics of Steam Turbine Blades

Study on Impact Damage Characteristics of Steam Turbine Blad...

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Electrical Engineering and Automation (IFEEA), International Forum on

作者： Song Yang Liu Chunlin Liu Yong Beijing China Science and Technology on Thermal Energy and Power Laboratory Wuhan Second Ship Design and Research Institute Wuhan China

ISBN: (数字)9781728196275

ISBN: (纸本)9781728196282

In order to provide accurate input conditions for the design and installation process of steam turbine blades, finite element models of transverse impingement blades and vertical impingement blades were established respectively, and the impact acceleration was used as the input load in calculation of impact stress distribution cloud map of the steam turbine blade and the impact stress response history. The maximum impact stress of the blade appears in the edge flow part of the blade. In order to verify the simulation calculation results, the simulation calculation model is used as the object to carry out the drop weight impact test. The drop weight heights are 20cm, 40cm, 60cm, 80cm and 100cm. The time-domain impact response of the blade is calculated using an explicit stepwise integration algorithm. When the blade is subjected to a lateral impact load of 100cm drop height acceleration (about 4.43m/s), the maximum stress at the blade measurement point is 23.5MPa, which is still much smaller than the static yield strength of the blade material.

关键词： Blades Data models Acceleration Stress Turbines Load modeling Strain

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