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Influence of an inserted bar on the flow regimes in the hopper

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Chinese Physics B 2021年第2期30卷 535-539页

作者： Yi Peng Sheng Zhang Mengke Wang Guanghui Yang Jiangfeng Wan liangwen chen Lei Yang Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China East China University of Technology Nanchang 330000China

We investigated the influence of an inserted bar on the hopper flow *** geometrical parameters,size of upper outlet D1,size of lower outlet D0,and the height of bar H,are variables *** varying H we found three regimes:one transition from clogging to a surface flow and another transition from a surface flow to a dense *** the dense flow,the flow rate follows Beverloo’s law and there is a saturation of inclination of free surfaceθ.We plotted the velocity field and there is a uniform linear relation between the particle velocity and depth from the free *** also found that the required value of D_(1) to guarantee the connectivity of flow is little smaller than D_(0).For the transition from a surface flow to a dense flow,there is a jump of flow rate and the minimumθfor flowing is two degrees larger than the repose angle.

关键词： hopper flow inserted bar flow type transition free surface velocity distribution

Effects of the Point Detector Approximation in Sterile Neutrino Search at CMIF

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IMP & HIRFL Annual Report 2019年第1期 214-217页

作者： chen liangwen Cai Hanjie Yang Lei 不详

Since been theoretically introduced by Pauli4l,neutrinos is deemed as one of the most enigmatic elementary particles in the *** Aavor oscillations of neutrinos have been discovered in solar and atmosphere neutrino exp... 详细信息

关键词： Approximation elementary independently

Laser-induced breakdown spectroscopy as a method for millimeter-scale inspection of surface flatness

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Plasma Science and Technology 2024年第9期26卷 148-155页

作者： Jinrui YE Yaju LI Zhao ZHANG Xinwei WANG Kewei TAO Qiang ZENG liangwen chen Dongbin QIAN Shaofeng ZHANG Lei YANG Xinwen MA Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000People’s Republic of China Advanced Energy Science and Technology Guangdong LaboratoryHuizhou 516000People’s Republic of China University of the Chinese Academy of Sciences Beijing 100049People’s Republic of China Key Laboratory of Atomic and Molecular Physics&Functional Materials of Gansu Province College of Physics and Electronic EngineeringNorthwest Normal UniversityLanzhou 730070People’s Republic of China Queen Mary University of London Engineering School Northwestern Polytechnical UniversityXi’an 710072People’s Republic of China

A non-contact method for millimeter-scale inspection of material surface flatness via Laser-Induced Breakdown Spectroscopy(LIBS)is investigated *** experiment is performed using a planished surface of an alloy steel sample to simulate its various flatness,ranging from 0 to 4.4 mm,by adjusting the laser focal plane to the surface distance with a step length of 0.2 *** is found that LIBS measurements are successful in inspecting the flatness differences among these simulated cases,implying that the method investigated here is *** is also found that,for achieving the inspection of surface flatness within such a wide range,when univariate analysis is applied,a piecewise calibration model must be *** is due to the complex dependence of plasma formation conditions on the surface flatness,which inevitably complicates the inspection *** solve the problem,a multivariate analysis with the help of Back-Propagation Neural Network(BPNN)algorithms is applied to further construct the calibration *** detailed analysis of the model performance,we demonstrate that a unified calibration model can be well established based on BPNN algorithms for unambiguous millimeter-scale range inspection of surface flatness with a resolution of about 0.2 mm.

关键词： laser-induced breakdown spectroscopy machine learning surface flatness

A New IsoDAR Method for Sterile Neutrino Search with d+^(9)Be Reaction

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IMP & HIRFL Annual Report 2017年第1期 205-207页

作者： chen liangwen Cai Hanjie Emilio Ciuffoli Jarah Evslin Zhang Sheng chen Xurong Yang Lei 不详

Neutrino oscillations have been observed in solar and atmosphere neutrino experiments[1,2],and confirmed independently by accelerator and reactor neutrino experiments[3-5].However,some anomalies have been observed in neutrino experiments with different sources,detector principles and detection channels[6-13],which can not be accommodated within the standard three-flavour neutrino *** anomalous results may be a sign of further new physics beyond Standard Model and currently their most popular interpretation is the existence of sterile neutrino states with masses at the eV *** neutrino states are a key issue in searches for new physics beyond the Standard Model,and their existence and properties would also have important implications in astrophysics and cosmology.

关键词： independently states principles

生产率、城市规模与经济密度:对城市集聚经济效应的实证研究

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贵州社会科学 2007年第2期 113-119页

作者：陈良文杨开忠北京大学北京100871

以Moomaw(1981b)和Ciccone等(1996)提出的模型为基础,利用1996年、2000年和2004年我国各地级市数据分析了城市生产率与城市规模、城市劳动生产率与城市经济密度的关系,结果显示城市规模和城市经济密度对城市生产率的影响都显著为正,各... 详细信息

以Moomaw(1981b)和Ciccone等(1996)提出的模型为基础,利用1996年、2000年和2004年我国各地级市数据分析了城市生产率与城市规模、城市劳动生产率与城市经济密度的关系,结果显示城市规模和城市经济密度对城市生产率的影响都显著为正,各年份城市生产率对城市人口规模的弹性介于0.6%-0.73%之间,城市劳动生产率对经济密度的弹性介于1%-1.9%之间,验证了城市集聚经济效应的存在,但城市集聚经济效应要弱于美国的水平。

关键词：集聚经济效应生产率城市规模经济密度

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中国城市体系演化的实证研究

江苏社会科学 2007年第1期 81-88页

作者：陈良文杨开忠吴姣北京大学政府管理学院博士生100871 中国日报社新闻中心 100029

对新中国成立以来特别是改革开放以来我国城市体系的演化过程进行了实证分析,发现1949年以来我国城市数量和城市平均规模都处于明显的上升过程。改革开放以来,我国城市首位度以及城市规模对数对城市位序对数的回归系数总体上趋于降低,... 详细信息

对新中国成立以来特别是改革开放以来我国城市体系的演化过程进行了实证分析,发现1949年以来我国城市数量和城市平均规模都处于明显的上升过程。改革开放以来,我国城市首位度以及城市规模对数对城市位序对数的回归系数总体上趋于降低,说明我国城市体系并不符合Zipf法则,同时也表明这一时期我国城市体系总体上呈扁平化发展趋势,但1996年以来这一趋势有所逆转。城市增长影响因素的分析结果显示,1990年以来大城市的增长速度要明显低于小城市,城市市场潜力、城市自然条件对城市增长速度有显著影响。

关键词：城市体系城市规模 Zipf法则首位度

广东省科技计划项目负责人信用评价指标体系研究

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科技进步与对策 2016年第20期33卷 122-127页

作者：吕亮雯陈宇山熊小满广东省科学技术情报研究所广东广州510033

在总结国内相关研究与实践的基础上,从政策文件、信用行为、评估需求等方面,深入分析了广东省科技计划项目负责人信用评价指标体系的构建依据,提出了评价指标体系的构建思路与原则,构建了一套较为系统、科学的评价指标体系,最后探讨性... 详细信息

在总结国内相关研究与实践的基础上,从政策文件、信用行为、评估需求等方面,深入分析了广东省科技计划项目负责人信用评价指标体系的构建依据,提出了评价指标体系的构建思路与原则,构建了一套较为系统、科学的评价指标体系,最后探讨性地提出了信用评分标准。

关键词：科技计划项目负责人信用评价

Estimating the yield stress of soft materials via laser-induced breakdown spectroscopy

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Chinese Physics B 2024年第3期33卷 428-432页

作者：龚书航李亚举钱东斌叶晋瑞赵扣曾强陈良文张少锋杨磊马新文 Advanced Energy Science and Technology Guangdong LaboratoryHuizhou 516000China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China

Taking three typical soft samples prepared respectively by loose packings of 77-,95-,and 109-μm copper grains as examples,we perform an experiment to investigate the energy-dependent laser-induced breakdown spectroscopy(LIBS)of soft *** discovered a reversal phenomenon in the trend of energy dependence of plasma emission intensity:increasing initially and then decreasing separated by a well-defined critical *** trend reversal is attributed to the laser-induced recoil pressure at the critical energy just matching the sample's yield *** a result,a one-to-one correspondence can be well established between the samples'yield stress and the critical energy that is easily obtainable from LIBS *** allows us to propose an innovative method for estimating the yield stress of soft materials via LIBS with attractive advantages including in-situ remote detection,real-time data collection,and minimal destructive to sample.

关键词： laser-induced breakdown spectroscopy soft materials yield stress

Estimating the grain size of microgranular material using laser-induced breakdown spectroscopy combined with machine learning algorithms

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Plasma Science and Technology 2024年第5期26卷 129-137页

作者：张朝李亚举杨光辉曾强李小龙陈良文钱东斌孙对兄苏茂根杨磊张少锋马新文 Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province College of Physics and Electronic EngineeringNorthwest Normal UniversityLanzhou 730070People’s Republic of China Advanced Energy Science and Technology Guangdong LaboratoryHuizhou 516000People’s Republic of China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000People’s Republic of China University of the Chinese Academy of Sciences Beijing 100049People’s Republic of China School of Nuclear Science and Technology University of the Chinese Academy of SciencesBeijing 100049People’s Republic of China

Recent work has validated a new method for estimating the grain size of microgranular materials in the range of tens to hundreds of micrometers using laser-induced breakdown spectroscopy(LIBS).In this situation,a piecewise univariate model must be constructed to estimate grain size due to the complex dependence of the plasma formation environment on grain *** the present work,we tentatively construct a unified calibration model suitable for LIBS-based estimation of those grain ***,two unified multivariate calibration models are constructed based on back-propagation neural network(BPNN)algorithms using feature selection strategies with and without considering prior *** detailed analysis of the performances of the two multivariate models,it was found that a unified calibration model can be successfully constructed based on BPNN algorithms for estimating the grain size in the range of tens to hundreds of *** was also found that the model constructed with a priorguided feature selection strategy had better prediction *** study has practical significance in developing the technology for material analysis using LIBS,especially when the LIBS signal exhibits a complex dependence on the material parameter to be estimated.

关键词： laser-induced breakdown spectroscopy machine learning randomly packed microgranular materials