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Measurement of air kerma rate and ambient dose equivalent rate using the G(E) function with hemispherical CdZnTe detector

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Nuclear Science and Techniques 2018年第3期29卷 71-77页

作者： ping huang National Institute of Measurement and Testing Technology Chengdu 610021China Sichuan Radiation Technology Co. LtdChengdu 610021China

Since the room-temperature detector CdZnTe(CZT) has advantages in terms of detection efficiency,energy resolution, and size, it has been extensively used to detect X-rays and gamma-rays. So far, nuclear radiation detectors such as cerium chloride doped with lanthanum bromide(LaBr_3(Ce)), thallium doped with cesium iodide(sI(Tl)), thallium doped with sodium iodide(NaI(Tl)),and high-purity germanium(HPGe) primarily use the spectroscopy-dose rate function(G(E)) to achieve the accurate measurement of air kerma rate(K_a) and ambient dose equivalent rate(H*(10)). However, the spectroscopy-dose rate function has been rarely measured for a CZT detector. In this study, we performed spectrum measurement using a hemispherical CZT detector in a radiation protection standards laboratory. The spectroscopy-dose rate function G(E) of the CZT detector was calculated using the least-squares method combined with the standard dose rate at the measurement position. The results showed that the hemispherical CZT detector could complete the measurement of air kerma rate(K_a) and ambient dose equivalent rate(H*(10)) by using the G(E) function at energies between 48 keV and 1.25 MeV, and the relative intrinsic errors were, respectively, controlled within ± 2. 3 and ± 2. 1%.

关键词： CdZnTe Spectroscopy-dose rate G(E) function Air kerma rate Ambient dose equivalent rate Relative intrinsic error

Numerical analysis of time-varying wear with elastic deformation in line contact

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Friction 2019年第2期7卷 143-152页

作者： Wanglong ZHAN ping huang School of Mechanical and Automotive Engineering South China University of Technology

Wear is an important factor for failures of mechanical components. Current research on wear is mainly focused on experiments while the numerical simulation of wear is hardly used owing to the complexities of the wear process. Explaining the effect of friction on the wear process is important, as it will lead to a deeper understanding of the evolution of wear. This study proposed a numerical method to expound the wear process in the contact between an elastic cylinder and a half-space simulating the ring-block tester. There are two difficulties during the calculation; one is that the contact shapes vary with time, causing the pressure distribution to change simultaneously and the other is the integral equation for calculating the contact pressure under different worn shapes. In the present study, the wear rate was computed using Archard's law and the wear process was calculated step by step until the specified total sliding distance was achieved. During each step of the calculation, the contact topography was updated. The simulation intuitively reproduced the contact state of change from line to surface contact throughout the wear process. Reasonable agreements on the changes of the wear scar, achieved from experiments and numerical simulations, were obtained.

关键词： time varying wear singular integral equation elastic deformation wear scars contact pressure

Diameter Preserving Surjection on Alternate Matrices

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Acta Mathematica Sinica,English Series 2009年第9期25卷 1517-1528页

作者： Li ping huang School of Mathematics and Computing Science Changsha University of Science and Technology Changsha 410076 China

Let F be a field with ｜F｜ ≥ 3, Km be the set of all m × m （m ≥ 4） alternate matrices over F. The arithmetic distance of A, B ∈ Km is d（A, B）：= rank（A - B）. If d（A, B） = 2, then A and B are said to be a... 详细信息

Let F be a field with ｜F｜ ≥ 3, Km be the set of all m × m （m ≥ 4） alternate matrices over F. The arithmetic distance of A, B ∈ Km is d（A, B）：= rank（A - B）. If d（A, B） = 2, then A and B are said to be adjacent. The diameter of Km is max{d（A, B）： A, B ∈ km}. Assume that φ ： Km→Km is a map. We prove the following are equivalent：（a） φ is a diameter preserving surjection in both directions, （b） φ is both an adjacency preserving surjection and a diameter preserving map, （c） φ is a bijective map which preserves the arithmetic distance.

关键词： geometry of matrices alternate matrix arithmetic distance adjacency diameter

Adjacency Preserving Bijection Maps of Hermitian Matrices over any Division Ring with an Involution

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Acta Mathematica Sinica,English Series 2007年第1期23卷 95-102页

作者： Li ping huang School of Mathematics Changsha University of Science & Technology Changsha 410076 P. R. China

Let D be any division ring with an involution,Hn （D） be the space of all n × n hermitian matrices over D. Two hermitian matrices A and B are said to be adjacent if rank（A - B） = 1. It is proved that if φ is a bijective map from Hn（D）（n ≥ 2） to itself such that φ preserves the adjacency, then φ^-1 also preserves the adjacency. Moreover, if Hn（D） ≠J3（F2）, then φ preserves the arithmetic distance. Thus, an open problem posed by Wan Zhe-Xian is answered for geometry of symmetric and hermitian matrices.

关键词： division ring with involution hermitian inatrix adjacency geometry of matrices

Superiority of a Convolutional Neural Network Model over Dynamical Models in Predicting Central Pacific ENSO

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Advances in Atmospheric Sciences 2024年第1期41卷 141-154页

作者： Tingyu WANG ping huang Center for Monsoon System Research Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD) Nanjing University of Information Science&TechnologyNanjing 210044China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China

The application of deep learning is fast developing in climate prediction,in which El Ni?o–Southern Oscillation(ENSO),as the most dominant disaster-causing climate event,is a key *** studies have shown that deep learning methods possess a certain level of superiority in predicting ENSO *** present study develops a deep learning model for predicting the spatial pattern of sea surface temperature anomalies(SSTAs)in the equatorial Pacific by training a convolutional neural network(CNN)model with historical simulations from CMIP6 *** with dynamical models,the CNN model has higher skill in predicting the SSTAs in the equatorial western-central Pacific,but not in the eastern *** CNN model can successfully capture the small-scale precursors in the initial SSTAs for the development of central Pacific ENSO to distinguish the spatial mode up to a lead time of seven months.A fusion model combining the predictions of the CNN model and the dynamical models achieves higher skill than each of them for both central and eastern Pacific ENSO.

关键词： ENSO diversity deep learning ENSO prediction dynamical forecast system

Lubricating performances of graphene oxide and onion-like carbon as water-based lubricant additives for smooth and sand-blasted steel discs

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Friction 2020年第1期8卷 47-57页

作者： Fenghua SU Guofu CHEN ping huang School of Mechanical and Automotive Engineering South China University of TechnologyGuangzhou 510641China

Graphene oxide(GO)nanosheets and onion‐like carbon(OLC)nanoparticles were synthesized from natural graphite powder and candle soot,respectively,and characterized by transmission electron microscopy and Raman *** lubricating performances of GO and OLC as lubricant additives in water were comparatively evaluated using a ball‐on‐disc *** effects of sand blasting of a steel disc on its morphology and tribological property were *** results show that the two nanomaterials,GO and OLC,when used as lubricant additives in water effectively reduce the friction and wear of the sliding discs,which is independent of the disc surface *** applying heavy loads,it is observed that GO exhibits superior friction‐reducing and anti‐wear abilities compared to those of OLC—a trace amount of GO can achieve a lubricating ability equivalent to that of an abundant amount of ***,it is observed that sand blasting cannot improve the wear resistance of the treated steel disc,even though the hardness of the disc increased after the *** possible anti‐wear and friction‐reducing mechanisms of the GO and OLC as lubricant additives in water are discussed based on results for the wear surfaces obtained by scanning electron microscopy,Raman spectroscopy,and X‐ray photoelectron spectroscopy。

关键词： graphene oxide onion‐like carbon lubricant additive friction and wear

Inverse grain-size-dependent strain rate sensitivity of face-centered cubic high-entropy alloy

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Journal of Materials Science & Technology 2021年第27期86卷 251-259页

作者： Lili Xiao ping huang Fei Wang State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and EngineeringXi’an Jiaotong UniversityXi’an710049China State Key Laboratory for Strength and Vibration of Mechanical Structures School of Aerospace EngineeringXi'an Jiaotong UniversityXi’an710049China

It is well documented that the strain rate sensitivity(m)increases at refined grain size for face-centered cubic(FCC)metals and *** a series of nanoindentation testing,however,we experimentally demonstrated a striking departure from conventional FCC metals that Co Cr Fe Mn Ni high entropy alloy(HEA)with FCC lattice structure exhibits monotonously decreased m as grain size reduced fromμ30.3m to 7.2 ***,the apparent activation volume v*,which generally shows an opposite trend of m,exhibited the identical decreasing trend with reduced grain size as that of *** an unusual trend of m and its correlation with v*in the FCC HEA alloys can be understood by a distinct deformationmechanism-transitions and unique dislocation morphology evolution that differs from conventional FCC metals.

关键词： High entropy alloy Strain rate sensitivity Activation volume Deformation mechanism Wavy dislocation

Enhanced Hall-Petch strengthening in graphene/Cu nanocomposites

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Journal of Materials Science & Technology 2021年第28期87卷 176-183页

作者： Shuang Zhang Fei Wang ping huang State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and EngineeringXi’an Jiaotong UniversityXi’an710049China State Key Laboratory for Strength and Vibration of Mechanical Structures School of AerospaceXi’an Jiaotong UniversityXi’an710049China

Grain size dependent strength,known as Hall-Petch relation,has been approved to be valid in crystalline metals and ***,softening would eventually occur as grain size reduced into nanoscale that below a critical ***,it is essential to find a way to break the strength limitation by avoiding the deformation mechanism transition from dislocation-mediated to grain-boundary-mediated *** replacing grain boundary(GB)of nanocrystalline Cu with graphene,in the present study,molecular dynamics simulations show that graphene-boundary(GrB)embedded GrB/Cu nanocomposites exhibit enhanced enlarged Hall-Petch slope with decreasing grain *** absence of inverse-Hall-Petch relation and the extremely high strength derived at the GrB/Cu nanocomposites were interpreted by the high back stress and abundant dislocation activity that attributed from the high-degree of heterogeneous structure of the nanocomposites.

关键词： Hall-Petch relation Graphene composite Strengthening Molecular dynamics simulation Dislocations

Evaluating the Formation Mechanisms of the Equatorial Pacific SST Warming Pattern in CMIP5 Models

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Advances in Atmospheric Sciences 2016年第4期33卷 433-441页

作者： Jun YING ping huang Ronghui huang Center for Monsoon System Research Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100190 University of Chinese Academy of Sciences Beijing 100049 Joint Center for Global Change Studies Beijing 100875

Based on the historical and RCP8.5 runs of the multi-model ensemble of 32 models participating in CMIP5, the present study evaluates the formation mechanisms for the patterns of changes in equatorial Pacific SST under global warming. Two features with complex formation processes, the zonal E1 Nifio-like pattern and the meridional equatorial peak warm- ing （EPW）, are investigated. The climatological evaporation is the main contributor to the E1 Nifio-like pattern, while the ocean dynamical thermostat effect plays a comparable negative role. The cloud-shortwave-radiation-SST feedback and the weakened Walker circulation play a small positive role in the E1 Nifio-like pattern. The processes associated with ocean dynamics are confined to the equator. The climatological evaporation is also the dominant contributor to the EPW pattern, as suggested in previous studies. However, the effects of some processes are inconsistent with previous studies. For example, changes in the zonal heat advection due to the weakened Walker circulation have a remarkable positive contribution to the EPW pattern, and changes in the shortwave radiation play a negative role in the EPW pattern.

关键词： global warming equatorial Pacific SST warming pattern multi-model ensemble CMIP5