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New evidence for lack of CMB power on large scales

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Science china(physics,Mechanics & Astronomy) 2010年第3期53卷 567-570页

作者： liu hao1 & {2. {2.1,2.3 1 key laboratory of particle astrophysics, institute of high energy physics, chinese academy of sciences, Beijing 100049, china 2.Department of {12. & Center for astrophysics, Tsinghua University, Beijing 100084, china 3 Department of Engineering {12. & Center for astrophysics, Tsinghua University, Beijing 100084, china key laboratory of {2. astrophysics Institute of High Energy Physics Chinese Academy of Sciences Department of physics & Center for astrophysics Tsinghua University Department of Engineering physics & Center for astrophysics Tsinghua University

A digitalized temperature map is recovered from the first light sky survey image published by the Planck team, from which an angular power spectrum of the cosmic microwave background (CMB) is derived. The amplitudes of the low multipoles (low-l) measured from the preliminary Planck power spectrum are significantly lower than those reported by the WMAP team. Possible systematical effects are far from enough to explain the observed low-l differences.

关键词： cosmology cosmic microwave background data analysis

Inconsistency between WMAP data and released map

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chinese Science Bulletin 2010年第10期55卷 907-909页

作者： liu hao1 & {2. {2.1,2.3 1 key laboratory of particle astrophysics,institute of high energy physics,chinese academy of sciences,Beijing 100049,china 2.Department of {12. & Center for astrophysics,Tsinghua University,Beijing 100084,china 3 Department of Engineering {12. & Center for astrophysics,Tsinghua University,Beijing 100084,china key laboratory of {2. astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing China Department of physics & Center for astrophysics Tsinghua University Beijing China Department of Engineering physics & Center for astrophysics Tsinghua University Beijing China

A remarkable inconsistency between the calibrated differential time-ordered data (TOD) of the Wilkinson Microwave Anisotropy Probe (WMAP) mission,which is the input for map-making,and the cosmic microwave background (CMB) temperature maps published by the WMAP team is revealed,indicating that there must exist a serious problem in the map making routine of the WMAP *** inconsistency is easy to be confirmed without the use of WMAP map-making *** view of the importance of this issue for cosmology study,we invite readers to check it by themselves.

关键词：威尔金森微波各向异性探测器 WMAP 地图制作宇宙微波背景有序数据制作软件 TOD CMB

Experimental Investigation and X-Ray Computed Microtomography Simulation on Thermal Physical Properties of Foundation Materials after Molten Salt Leakage in the Storage Tank

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Journal of Thermal Science 2024年第2期33卷 591-601页

作者： WANG Zhaowen ZHOU hao LUO Jiawei {2. Yawei FANG hao liu Tianxiao State key laboratory of Clean {2. Utilization Institute for Thermal Power EngineeringZhejiang UniversityHangzhou310027China

This paper studied the thermal physical properties of foundation materials in the molten salt tank of thermal energy storage system after molten salt leakage by Transient plane source experiment and X-ray computed microtomography simulation *** microstructure,thermal properties and pressure resistance with different particle diameters were *** measured heat conductivities from Transient plane source experiment for three cases are 0.49 W/(m·K),0.48 W/(m·K),and 0.51 W/(m·K),and the porosity is 30.1%,30.7%,and 31.2. *** heat conductivity simulating results of three cases are 0.471 W/(m·K),0.482./(m·K),and 0.513 W/(m·K).The ratio of difference between the results of simulation and Transient plane source measurement is as low as 1.2.,verifying the re{2.abi{2.ty of experimental and simulation results to a certain *** with the heat conductivity of 0.097-0.12. W/(m·K) and porosity of 71.6%-78.9% without leaking salt,the porosity is reduced by more than 50% while the heat conductivity increased by 4 to 5 times after molten salt *** significant increase in heat conductivity has a great impact on security operation,structure design,and mode{2.ng of the tank foundation for solar power plants.

关键词： heat conductivity X-ray computed microtomography foundation materials three-phase threshold algorithm molten salt leakage

Implementation of a particle-in-cell method for the energy solver in 3D spherical geodynamic mode{2.ng

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Earth and Planetary physics 2024年第3期8卷 549-563页

作者： hao Dong ZeBin Cao liJun {2. YanChong li SanZhong li liMing Dai XinYu li Frontiers Science Center for Deep Ocean Multispheres and Earth System Key Laboratory of Submarine Geosciences and Prospecting TechniquesMinistry of Education and College of Marine GeosciencesOcean University of ChinaQingdao 266100China State key laboratory of {2.thospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China laboratory for Marine Geology Laoshan LaboratoryQingdao 266237China Department of Earth Science&Environmental Change University of Illinois at Urbana-ChampaignUrbanaIL 61801USA laboratory of Seismology and physics of Earth’s Interior School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China

The thermal evolution of the Earth’s interior and its dynamic effects are the focus of Earth ***,the commonly adopted grid-based temperature solver is usually prone to numerical oscillations,especially in the presence of sharp thermal gradients,such as when modeling subducting slabs and rising *** phenomenon prohibits the correct representation of thermal evolution and may cause incorrect implications of geodynamic *** examining several approaches for removing these numerical oscillations,we show that the Lagrangian method provides an ideal way to solve this *** this study,we propose a {2.-in-cell method as a strategy for improving the solution to the energy equation and demonstrate its effectiveness in both one-dimensional and three-dimensional thermal problems,as well as in a global spherical simulation with data *** have implemented this method in the open-source finite-element code CitcomS,which features a spherical coordinate system,distributed memory parallel computing,and data assimilation algorithms.

关键词： numerical oscillation overshooting and undershooting particle-in-cell method three-dimensional spherical geodynamic modeling energy solver finite element method

Normalized glandular dose coefficients for digital breast tomosynthesis using detailed chinese breast models

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Nuclear Science and Techniques 2024年第5期35卷 42-59页

作者： Jia-hao Wang Rui Qiu An-Kang Hu Ye-Qi liu Zhen Wu Hui Zhang Jun-{2. {2. Department of Engineering physics Tsinghua UniversityBeijing 100084China key laboratory of {2. and Radiation Imaging Ministry of EducationTsinghua UniversityBeijing 100084China Joint institute of Tsinghua University Nuctech Company Limited BeijingBeijing 100084China

The rise in breast cancer diagnoses among chinese women has necessitated the use of X-ray breast screening,which carries a radiation *** study aimed to provide a dosimetry protocol for the chinese female population to replace the traditional standard that uti{2.zes simp{2.fied breast models,for the accurate estimation of the mean glandular dose of a patient undergoing digital breast tomosynthesis(DBT).The first set of detailed chinese female breast models and representative breast parameters was *** backscatter radiation and computational efficiency,we improved the combination of these models and the chinese reference adult female whole-body voxel *** acquisition for four commercial DBT systems that are widely employed in china was simulated using the Monte Carlo method to obtain the norma{2.zed glandular dose coefficients of DBT(D_(gN)^(DBT))and the glandular depth dose(D_(g)^(dep)(z))for different breast characteristics and X-ray *** calculated a series of D_(gN)^(DBT) values for breasts with different percentage mass glandularities(5%,2.%,50%,75%,and 100%)and compressed breast thicknesses(2.3,4,5,6,and 7 cm)at various tube potentials(2.,2.,30,32.35,and 49 kV)and target/filter combinations(W/Rh,W/Al,Mo/Mo,Rh/Rh,and Rh/Ag).The parameter dependence of the breast characteristics and beam conditions on D_(gN)^(DBT) in detailed breast models was *** D_(gN)^(DBT) results were 14.6-51.0%lower than those of the traditional dosimetry standard in *** difference in D_(gN)^(DBT) was mainly due to a decrease in the depth of the main energy deposition area caused by the glandular distribution along the depth *** results obtained in this study may be used to improve breast dosimetry in china and provide more detailed information on risk assessment during DBT.

关键词： Digital breast tomosynthesis Normalized glandular dose coefficients Detailed breast model Monte Carlo simulation

The SLEGS beamline of SSRF

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Nuclear Science and Techniques 2024年第7期35卷 20-30页

作者： Long-Xiang liu Hong-Wei Wang Gong-Tao Fan Hang-Hua Xu Yue Zhang Zi-Rui hao Ai-Guo {2. Shanghai Advanced Research institute Chinese Academy of SciencesShanghai201210China

The Shanghai Laser Electron Gamma Source(SLEGS, located in BL03SSID) beamline at the Shanghai Synchrotron Radiation Facility(SSRF) is a Laser Compton Scattering(LCS) gamma source used for the investigation of nuclear structure, which is in extensive demand in fields such as nuclear {2., nuclear cluster structure, polarization physics, and nuclear energy. The beamline is based on the inverse Compton scattering of 10640 nm photons on 3.5 GeV electrons and a gamma source with variable energy by changing the scattering angle from 2.° to 160°. γ rays of 0.2.-2..1 MeV can be extracted by the scheme consisting of the interaction chamber, coarse collimator, fine collimator, and attenuator. The maximum photon flux for 180° is approximately 10~7 photons/s at the target at 2..7 MeV, with a 3-mm-diameter beam. The beamline was equipped with four types of spectrometers for experiments in( γ,γ'),( γ,n),( γ,p), and( γ,α). At present, Nuclear Resonance Fluorescence(NRF) spectrometry, Flat-Efficiency neutron Detector(FED) spectrometry, neutron Time-Of-Flight(TOF) spectrometry, and light-Charged {12.(LCP) spectrometry methods have been developed.

关键词： Shanghai Synchrotron Radiation Facility SLEGS Nuclear astrophysics Nuclear structure

Interaction Mechanisms between Natural Debris Flow and Rigid Barrier Deflectors:A New Perspective for Rational Design and Optimal Arrangement

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Computer Modeling in Engineering & sciences 2024年第5期139卷 1679-1699页

作者： Yu Huang Beilei liu Dianlei Feng hao Shi Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai200092China Department of Hydraulic Engineering College of Civil EngineeringTongji UniversityShanghai200092China

Rigid barrier deflectors can effectively prevent overspilling landslides,and can satisfy disaster prevention ***,the mechanisms of interaction between natural granular flow and rigid barrier deflectors require further *** date,few studies have investigated the impact of deflectors on controlling viscous debris flows for geological disaster *** investigate the effect of rigid barrier deflectors on impact mechanisms,a numerical model using the smoothed particle hydrodynamics(SPH)method with the Herschel–Bulkley model is proposed to simulate the interaction between natural viscous flow and single/dual barriers with and without *** model was validated using laboratory flume test data from the ***,the model was used to investigate the influence of the deflector angle and multi-barrier *** optimal configuration of multi-barriers was analyzed with consideration to the barrier height and distance between the barriers,because these metrics have a significant impact on the viscous flow pile-up,run-up,and overflow *** investigation considered the energy dissipation process,retention efficiency,and dead-zone *** with bare barriers with similar geometric characteristics and spatial distribution,rigid barriers with deflectors exhibit superior effectiveness in preventing the overflow and overspilling of viscous debris *** for the rational design of deflectors and the optimal arrangement of multi-barriers are provided to mitigate geological disasters.

关键词： Rigid barrier deflectors deflector angle single-barrier dual-barrier arrangements viscous debris flow over-spilling delta-plus-SPH

Research progresses of nanomaterials as lubricant additives

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Friction 2024年第7期12卷 1347-1391页

作者： Zhengquan JIANG Yankun SUN Bokang liu Laigui YU Yuping TONG Mingming YAN Zhongzheng YANG Yongxing hao {2.njian SHANGGUAN Shengmao ZHANG Weihua {2. School of Materials Science and Engineering North China University of Water Resources and Electric PowerZhengzhou 450045China institute of Special Friction and Lubricating Materials North China University of Water Resources and Electric PowerZhengzhou 450045China Nanomaterials Engineering Research Center Henan UniversityKaifeng 475001China School of Mechanical Engineering North China University of Water Resources and Electric PowerZhengzhou 450045China

Friction and wear are unavoidable in mechanical *** use of lubricants with nano-additives can effectively reduce friction and wear,which is of great significance to saving energy and protecting the *** present,great progress has been made in the scientific research and industrial application of nano-additives for *** paper mainly introduces the types of nano-additives for lubricants(such as carbon nanomaterials,nano-metals,nano-oxides,sulfides,complexes,polymers,etc.),the tribological properties of lubricants with different components of nano-additives,and the lubrication mechanisms of the nano-additives(including tribofilm formation,rolling ball bearing effect,repairing effect,polishing effect,and synergistic effect).It also deals with the dispersion of nano-additives in lubricants and the influences of their particle size and microstructure on the tribological properties of *** review outlines the performance requirements of nano-additives in different lubrication states,discusses the use of nano-additives in challenging working conditions,and identifies various industrial oil nano-additives with reference to the appropriate options in diverse working ***,the existing problems of nano-additives and their application prospects are *** review,hopefully,would help to shed light on the design and synthesis of novel high-performance nano-additives and promote their application in engineering.

关键词： nanomaterials lubricant additive lubrication mechanism research progress

Effect of coral sand on the mechanical properties and hydration mechanism of magnesium potassium phosphate cement mortar

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Journal of Zhejiang University-Science A(Applied physics & Engineering) 2024年第2期25卷 116-129页

作者： hao liu Huamei YANG Houzhen WEI Jining YU Qingshan MENG Rongtao YAN College of Civil Engineering and Architecture Guilin University of TechnologyGuilin541004China Guangxi key laboratory of Geomechanics and Geotechnical Engineering Guilin University of TechnologyGuilin541004China State key laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China School of Intelligent Construction Wuchang University of TechnologyWuhan430002China Hydraulic Concrete institute China Three Gorges CorporationBeijing100038China The First Railway Survey and Design institute Group Corporation Xi’an710043China

Damaged structures on coral islands have been spalling and cracking due to the dual corrosion of tides and *** ensure easy access to aggregate materials,magnesium potassium phosphate cement(MKPC)and coral sand(CS)are mixed to repair damaged structures on coral ***,CS is significantly different from land-sourced sand in mineral composition,particle morphology,and *** has a substantial impact on the hydration characteristics and macroscopic properties of MKPC ***,in this study we investigated the compressive strength,interfacial mechanical properties,and corrosion resistance of MKPC CS *** in the morphology,microstructure,and relative contents of hydration products were revealed by scanning electron microscope-{2. dispersive spectrometer(SEM-EDS)and X-ray diffraction(XRD).The results indicated that the compressive strength increased linearly with the interfacial micro-hardness,and then stabilized after long-term immersion in pure water and Na2.O4 solution,showing excellent corrosion *** with MKPC river sand(RS)mortar,the hydration products of CS mortar were an intermediate product 6KPO2.8H2. with a relative content of 3.9%at 1 h and 4.1%at 12.*** hydration product MgKPO_(4)·6H_(2.O increased rapidly after 7-d curing,with an increased growth rate of 1100%.Our results showed that CS promoted the nucleation and formation of hydration products of MKPC,resulting in better crystallinity,tighter overlapping,and a denser interfacial transition *** results of this study provide technical support for applying MKPC mortar as a rapid repair material for damaged structures on coral islands.

关键词： Magnesium potassium phosphate cement(MKPC) Coral sand(CS) Mechanical properties Corrosion resistance Hydration mechanism