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Room-temperature test system for 162.5 MHz high-power couplers

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Nuclear Science and Techniques 2019年第1期30卷 35-41页

作者： Long Chen Shen-Hu Zhang Yong-Ming Li Ruo-Xu Wang Tiancai Jiang Lei Yang chun-Long Li An-Dong Wu shi-chun Huang Feng Pan Xin-Meng Liu Yuan He University of Chinese Academy of Sciences Institute of Modern Physics Chinese Academy of Sciences

Fundamental power couplers are crucial components for feeding radio frequency power to accelerating cavities. Couplers must be tested and conditioned on a room-temperature test stand to evaluate and potentially improve their performance before being installed in an accelerating cavity. A new test system has been designed and is under construction at the institute of modern *** this test system, multiple conditioning modes, including the pulse mode, CW mode, and amplitude-sweeping mode, have been embedded in the low-level radio frequency system of the test stand. All of these conditioning modes can be run manually or automatically. In addition, a novel test cavity is proposed and has been designed, which facilitates non-contact conditioning and a multi-purpose test stand.

关键词： Couplers conditioning Test stand LLRF control system Test cavity

Improving energy utilization efficiency of electrical discharge milling in titanium alloys machining

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Journal of Central South University 2016年第10期23卷 2550-2557页

作者：郭成波韦东波狄士春 School of Mechatronics Engineering Harbin Institute of Technology State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University

Electrical discharge milling(ED-milling) can be a good choice for titanium alloys machining and it was proven that its machining efficiency can be improved to compete with mechanical cutting. In order to improve energy utilization efficiency of ED-milling process, unstable arc discharge and stable arc discharge combined with normal discharge were implemented for material removal by adjusting servo control strategy. The influence of electrode rotating speed and dielectric flushing pressure on machining performance was investigated by experiments. It was found that the rotating of electrode could move the position of discharge plasma channel, and high pressure flushing could wash melted debris out the discharge gap effectively. Both electrode rotating motion and high pressure flushing are contributed to the improvement of machining efficiency.

关键词： electrical discharge milling electrode rotating dielectric flushing energy utilization efficiency material removal rate tool electrode wearing rate

Factors influencing the accuracy of the denitrifier method for determining the oxygen isotopic composition of nitrate

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2019年第1期20卷 49-58页

作者： Man ZHANG Jia-chun shi Lao-sheng WU Institute of Soil and Water Resources and Environmental Science College of Environmental and Resource Sciences Zhejiang Provincial Key Laboratory of Agricultural and Environment Zhejiang University Department of Environmental Sciences University of California

The denitrifier method is widely used as a novel pretreatment method for the determination of nitrogen and oxygen isotope ratios as it can provide quantitative and high-sensitivity measurements. Nevertheless, the method is limited by relatively low measurement accuracy for δ18 O. In this study, we analyzed the factors influencing the accuracy of δ18 O determination, and then systematically investigated the effects of dissolved oxygen concentrations and nitrate sample sizes on estimates of the δ15 N and δ18 O of nitrate reference materials. The δ18 O contraction ratio was used to represent the relationship between the measured difference and true difference between two reference materials. We obtained the following main results:(1) a gas-liquid ratio of 3:10(v/v) in ordinary triangular flasks and a shaking speed of 120 r/min produced an optimal range(1.9 to 2.6 mg/L) in the concentration of dissolved oxygen for accurately determining δ18 O, and(2) the δ18 O contraction ratio decreased as nitrate sample size decreased within a certain range(1.0 to 0.1 μmol). Our results suggested that δ18 O contraction is influenced mainly by dissolved oxygen concentrations in pure culture, and provided a model for improving the accuracy of oxygen isotope analysis.

关键词： Denitrifier method Nitrate δ^15N δ^18O Dissolved oxygen δ^18O contraction

Understanding Mass Dependence of Glass Formation in Ring Polymers

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Chinese Journal of Polymer Science 2023年第9期41卷 1447-1461,I0008页

作者： Xiang-Yu Song Zhen-Yue Yang Qi-Lu Yuan Shang-Wei Li Zi-Qiang Tang Yue-Tong Dong shi-chun Jiang Wen-Sheng Xu State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei230026China School of Materials Science and Engineering Tianjin UniversityTianjin300072China

Having highly tunable molecular topology is one of the most important characteristics of polymers that provides these materials with a wide range of interesting and unique *** particular,ring polymers exhibit a number of properties that are markedly distinct from their linear ***,we compare and contrast the glass formation of unknotted,nonconcatenated ring and linear polymer melts having variable molecular mass based on molecular dynamics simulations of a coarse-grained *** revealing an unusual property in the structure of small rings,we discuss the mass dependence of the structural relaxation time determined from the self-intermediate scattering function over a wide range of temperatures in both ring and linear *** a general trend,we find that the characteristic temperatures(e.g.,the glass transition temperature)and fragility of glass formation increase with increasing molecular mass in linear polymers,but the mass dependences of these properties are rather weak in the family of ring polymer models considered,in broad accord with experimental ***,we show that the glass formation of ring polymers can quantitatively be described by the string model,a model that is broadly consistent with the entropy theory of glass formation and that takes the mass of string-like clusters as a molecular realization of the abstract cooperatively rearranging *** opens the possibility of applying the configurational entropy-based theories to describe the glass formation of ring polymers,once the ring topology is taken into account.

关键词： Ring polymers Glass formation String model Molecular dynamics simulation

Study on the Structure of a Horizontal Shear Line over the Tibetan Plateau Based on CRA-Interim Datasets and Its Comparison with ERA-Interim Datasets

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Journal of Tropical Meteorology 2020年第4期26卷 483-494页

作者： YAO Xiu-ping ZHANG Shuo BAO Xiao-hong shi chun-xiang LIU Jing-wei China Meteorological Administration Training Centre Beijing 100081 China Beijing Institute of Applied Meteorology Beijing 100029 China Chinese Academy of Meteorological Sciences Beijing 100081 China National Meteorological Centre Beijing 100081 China

The CRA-Interim trial production of the global atmospheric reanalysis for 10 years from 2007 to 2016 was carried out by the China Meteorological Administration in 2017. The structural characteristics of the horizontal shear line over the Tibetan Plateau (TPHSL) based on the CRA-Interim datasets are examined by objectively identifying the shear line, and are compared with the analysis results of the European Centre for Medium-Range Weather Forecasts reanalysis data (ERA-Interim). The case occurred at 18UTC on July 5, 2016. The results show that both of the ERA-Interim and CRA-Interim datasets can well reveal the circulation background and the dynamic and thermal structure characteristics of TPHSL, and they have shown some similar features. The middle and high latitudes at 500 hPa are characterized by the circulation situation of"two troughs and two ridges", and at 200 hPa, the TPHSL is located in the northeast quadrant of the South Asian High Pressure (SAHP). The TPHSL locates in the positive vorticity zone and passes through the positive vorticity center corresponding to the ascending motion. Near the TPHSL, the contours of pseudo-equivalent potential temperature (θse) tend to be intensive, with a high-value center on the south side of the TPHSL. The TPHSL can extend to460 hPa and vertically inclines northward. There is a positive vorticity zone near the TPHSL which is also characterized by the northward inclination with the height, the ascending motion near the TPHSL can extend to 300 hPa, and the atmospheric layer above the TPHSL is stable. However, the intensities of the TPHSL’s structure characteristics analyzed with the two datasets are different, revealing the relatively strong intensity of geopotential height field, vertical velocity field, vorticity field and divergence field from the CRA-Interim datasets. In addition, the vertical profiles of the dynamic and water vapor thermal physical quantities of the two datasets are also consistent in the east and west

关键词： CRA-Interim datasets ERA-Interim datasets horizontal shear line over the Tibetan Plateau structure

Spectroscopic Studies on Charge Transfer from Ce^(3+) to Yb^(3+) in KMgF_3∶Ce,Yb Nanocrystals

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Chemical Research in Chinese Universities 2007年第4期23卷 395-398页

作者： YAN Jing-hui ZHANG Hai-yan LI Zhong-tian CAO Jie SONG Li-hong ZHANG Hui-qiu shi chun-shan College of Chemistry and Environmental Engineering Changchun University of Science and Technology Changchun 130022 P. R. China Key Laboratory of Rare Earth Chemistry and Physics Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 P. R. China

Nanocrystals of KMgF3 single-doped and codoped with Ce^3＋ or/and Yb^3＋ were synthesized separately by the mi-croemulsion method. The X-ray diffraction（XRD） patterns were indexed to show that the KMgF3 crystal system was unchanged. The fluorescent spectra of KMgF3： Ce, Yb polycrystal powders were studied and compared with those of the Ce,Yb doped KMgF3 crystals produced using the high-temperature solid phase method. The diffuse reflection spectra and infrared emission of KMgF3： Ce, Yb were investigated. From the results, the authors could confirm that there were charge transfer processes from Ce^3＋ to Yb^3＋ in both KMgF3： Ce,Yb nanocrystals and polycrystal powders.

关键词： Microemulsion Nanocrystal Fluorescent spectra Charge transfer

Luminescent properties of Ba_3(PO_4)_2:Eu,Tb phosphors

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Chinese Journal of Chemistry 1996年第5期14卷 399-403页

作者： GAO,Yong shi,chun-ShanLaboratory of Rare Earth Chemistry and Physics,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun,Jilin 130022,China Laboratory of Rare Earth Chemistry and Physics Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun Jilin 130022 China

Luminescence of europium (Ⅲ),europium(Ⅱ) and terbium(Ⅲ) has been observed in Bas(PO4)2:Eu,Tb phosphors which are synthesized in air *** valence state of europium is influenced by amount of *** is notable that the relative intensity of the emission spectra peaks corresponding to Eu2+ is increased if the amount of Tb3+ is *** phenomena can be explained by an electron transfer *** predict a new kind of two-rare-earth codoped trichromatic phosphors in Ba3(PO4)2 matrix.

关键词： Luminescence europium terbium phosphor

CHAIN:unlocking informatics-aided design of Li metal anode from materials to applications

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Rare Metals 2022年第5期41卷 1477-1489页

作者： Li-Sheng Zhang Xin-Lei Gao Xin-Hua Liu Zheng-Jie Zhang Rui Cao Han-Chao Cheng Ming-Yue Wang Xiao-Yu Yan shi-chun Yang School of Transportation Science and Engineering Beihang UniversityBeijing 100191China

With the rapid development of consumer electronics,electric vehicles and grid-scale stationary energy storage,high-energy batteries are urgently demanded at *** metal batteries(LMBs)are considered to be one of the most promising high-energy density energy storage devices at present and have received much attention due to their ultra-high theoretical capacity,extremely low electrochemical potential and light ***,critical issues,such as uncontrollable lithium dendrite growth,dynamic changes in volume,interfacial impedance,severe chemical and electrochemical corrosion,remain huge challenges for Li metal anodes,which not only lead to low Columbic efficiency of LMBs,but also pose the risk of internal short circuit,causing serious side reactions and safety concerns that hinder LMBs from practical ***,lithium metal is gradually poised for a revival after decades of oblivion,due to the development of research tools and nanotechnologybased *** this review,various recent material designs for lithium metal anodes are reviewed based on previous theoretical understanding and *** Li dendrites and ensuring the long life span of practical batteries through limited Li metal anodes design are still ***-scale modeling methods are concerned,requiring the application of electrode material *** multi-scale modeling application methods with machine learning technology are proposed based on the cloud computing *** material designs for Li metal anodes on model information are integrated with artificial ***,this review provides a novel framework for next-generation lithium metal anode design methods with a digital solution based on multi-scale data-driven models and machine learning techniques.

关键词： Li metal anodes Energy materials Multi-scale modeling Fusion of model and data Digital twin CHAIN

Progress and prospects of graphene-based materials in lithium batteries

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Rare Metals 2024年第5期43卷 1886-1905页

作者： Shen Lai Tao Huang Pei Liu Hong-Bin Wang shi-chun Yang Xin-Hua Liu Kai Yang Qian-Ling Zhang Jian-Hong Liu Jiang-Tao Hu Graphene Composite Research Center College of Chemistry and Environmental EngineeringShenzhen UniversityShenzhen 518060China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China Shenzhen Eigen-Equation Graphene Technology Co.Ltd Shenzhen518060China School of Transportation Science and Engineering Beihang UniversityBeijing 100191China Department of Electrical and Electronic Engineering Advanced Technology InstituteUniversity of SurreyGuildfordSurrey GU27XHUK

Reasonable design and applications of graphene-based materials are supposed to be promising ways to tackle many fundamental problems emerging in lithium batteries,including suppression of electrode/electrolyte side reactions,stabilization of electrode architecture,and improvement of conductive ***,extensive fundamental research on this aspect has been performed so ***,when it comes to large-scale industrial applications,the utilization of graphene-based materials progresses at a very slow ***,there presents a severe technological decoupling between academic research and industrial application,and there is an urgent need to link ***,in order to address current issues of graphene-based materials used in lithium batteries,we present their latest advancements with stateof-the-art *** applications of graphenebased materials in practical lithium batteries are highlighted and predicted to bridge the gap between the academic progress and industrial manufacture,thereby paving the way for accelerating the development of graphenebased material as well as lithium battery industry.

关键词： Lithium batteries Graphene-based materials Academic research Industrial application Development direction