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Isolated Bipolar Modular Multilevel DC-DC Converter with Self-balancing Capability for Interconnection of MVDC and LVDC Grids

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CSEE Journal of Power and Energy Systems 2023年第1期9卷 365-379页

作者： Jinmu Lai xin yin Yaoqiang Wang Lin Jiang Zia Ullah Xianggen yin School of Electrical and Information EngineeringZhengzhou UniversityZhengzhou 450001China Department of Electrical Engineering and ElectronicsUniversity of LiverpoolLiverpoolUK State Key Laboratory of Advanced Electromagnetic Engineering and TechnologyHuazhong University of Scienceand TechnologyWuhan 430074China

Bipolar medium-voltage DC(MVDC)and lowvoltage DC(LVDC)grids have the advantages of flexible integration of distributed renewable-energy generation and reliable power *** order to achieve voltage conversion,power transfer,and electrical isolation for bipolar MVDC and LVDC grids,a high-power DC-DC converter is ***,this paper proposes an isolated bipolar modular multilevel DCDC converter(BiMMDC)with power self-balancing capability for interconnection of MVDC and LVDC *** proposed BiMMDC consists of two series connected MMCs in the MV stage to configure a bipolar MVDC interface,and interleaved converters combined with a dual-transformer are designed in the LV stage to configure the bipolar LVDC interface and to provide a self-balancing *** circuits of two series-connected MMCs and a dual-transformer with interleaved converters are *** that,operation principles of the proposed BiMMDC are introduced,considering balanced/unbalanced power transfer of bipolar LVDC grid and monopolar shortcircuit or open-circuit faults at MVDC *** control scheme is also presented for the proposed BiMMDC under different operating ***,a Matlab simulation and controller hardware-in-the-loop(CHIL)evaluation results are provided to validate the feasibility and effectiveness of the proposed typology and its operating performance.

关键词： Bipolar DC-DC converter equivalent circuit modular monopolar operation multilevel self-balancing

TZ Lyrae:an Algol-type Eclipsing Binary with Mass Transfer

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Chinese Journal of Astronomy and Astrophysics 2007年第2期7卷 258-264页

作者： Yuan-Gui Yang xin-Guo yin Physics Department of Huaibei Coal Industry Teachers College Huaibei 235000

We present a detailed investigation of the Algol-type binary TZ Lyrae, based on 55 light minimum timings spanning 90 years. It is found that the orbital period shows a long-term increase with a cyclic variation superimposed. The rate of the secular increase is dP/dt = ＋7.18 × 10^-8d yr^-1, indicating that a mass transfer from the less massive component to the more massive one at a rate of dra = ＋2.21 × 10^-8M⊙ yr^-1. The cyclic component, with a period of P3 = 45.5 yr and an amplitude of A = 0.^d0040, may be interpreted as either the light-time effect in the presence of a third body or magnetic activity cycles in the components. Using the latest version Wilson-Devinney code, a revised photometric solution was deduced from B and V observations. The results show that TZ Lyr is an Algol-type eclipsing binary with a mass ratio of q = 0.297±0.003）. The semidetached configuration with a lobe-filling secondary suggests a mass transfer from the secondary to the primary, which is in agreement with the long-term period increase of the binary system.

关键词： stars binaries close - stars binaries eclipsing - stars individual TZ Lyrae

Stable Propagating Waves and Wake Fields in Relativistic Electromagnetic Plasma

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Communications in Theoretical Physics 2008年第3期49卷 753-758页

作者： XIE Bai-Song yin xin-Tao The Key Laboratory of Beam Technology and Materials Modification of Ministry of Education Beijing Normal University Beijing 100875 China

Stable propagating waves and wake fields in relativistic electromagnetic plasma are investigated. The incident electromagnetic field has a finite initial constant amplitude meanwhile the longitudinal momentum of electrons is taken into account in the problem. It is found that in the moving frame with transverse wave group velocity the stable propagating transverse electromagnetic waves and longitudinal plasma wake fields can exist in the appropriate regime of plasma.

关键词： nonlinear wave propagation laser-plasma interactions

Extent, reasons and consequences of off-labeled and unlicensed drug prescription in hospitalized children: a narrative review

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World Journal of Pediatrics 2021年第4期17卷 341-354页

作者： Wasim Shuib xin-yin Wu Fang Xiao Xiangya School of Public Health Central South UniversityChangsha410078China

Background Off-label and unlicensed prescriptions pose a severe safety concern among the pediatric *** aimed to summarize the up-to-date evidence on the extent,reasons,and consequences of off-label and unlicensed drugs in hospitalized pediatric *** We systematically searched PubMed,EMBASE,SCOPUS,Web of Science and Google Scholar between 1990 and 2020 in which the last search was conducted on 12 February *** included studies with the following inclusion criteria:(1)observational studies in design;(2)target population was hospitalized pediatric patients whether admitted in the intensive care unit or in the general ward;(3)study reporting the prevalence of off-label,unlicensed prescriptions or both;and(4)published in *** A total of 47 studies were eligible for *** proportion of off-label and unlicensed prescriptions ranged from 7.4%to 99.5%and 0.1%to 74.4%,*** most frequent category of off-label prescriptions was prescription outside the age range,with the most commonly reported reason for off-label prescriptions being the lack of information specifically for pediatrics on the drug information *** consequences of off-label and unlicensed prescriptions ranged from minor and bearable skin reactions to debilitating renal failure,risking *** Off-label and unlicensed prescriptions are extensive and require progressively meditative ***,the pediatric population is currently a“therapeutic orphan”.Unless adequate pediatric clinical trials and licensed drugs become available,off-label and unlicensed drug prescription should not entirely be banned but rather promoted in an organized manner.

关键词： Licensed medicines Off-label prescribing Pediatrics Unlicensed prescribing

Molecular cloning and expression analysis of turnip (Brassica rapa var. rapa) sucrose transporter gene family

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Plant Diversity 2017年第3期39卷 123-129页

作者： Yuanyuan Liu xin yin Ya Yang Chuntao Wang Key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of Botany Chinese Academy of Science Kunming 650201 China Plant Germplasm and Genornics Center The Germplasm Bank of Wild Species Kunming Institute of Botany Chinese Academy of Sciences Kunming650201 China University of the Chinese Academy of Sciences Beijing 100049 China

In higher plants, sugars （mainly sucrose） are produced by photosynthetically assimilated carbon in mesophyll cells of leaves and translocated to heterotrophic organs to ensure plant growth and devel- opment. Sucrose transporters, or sucrose carriers （SUCs）, play an important role in the long-distance transportation of sucrose from source organs to sink organs, thereby affecting crop yield and quality. The identification, characterization, and molecular function analysis of sucrose transporter genes have been reported for monocot and dicot plants. However, no relevant study has been reported on sucrose transporter genes in Brassica rapa vat. rapa, a cruciferous root crop used mainly as vegetables and fodder. We identified and cloned 12 sucrose transporter genes from turnips, named BrrSUC1.1 to BrrSUCB.2 according to the SUC gene sequences of B. rapa pekinensis. We constructed a phylogenetic tree and analyzed conserved motifs for all 12 sucrose transporter genes identified. Real-time quantitative poly- merase chain reaction was conducted to understand the expression levels of SUC genes in different tissues and developmental phases of the turnip. These findings add to our understanding of the genetics and physiology of sugar transport during taproot formation in turnips.

关键词： Brassica rapa vat. rapa Turnipsucrose transporter SUC

Particle Image Velocimetry Measurement of the Flow Field in the Play of the Drilling Pump Valve

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Chinese Journal of Mechanical Engineering 2010年第1期23卷 27-37页

作者： YANG Guoan yin xin SONG Zheng HUANG Cong Diagnosis ＆ Self-recovery Engineering Research Center Beo＇ing University of Chemical Technology Beijing 100029 China Production Operations Center PetroChina Guangxi Petrochemical Company Qinzhou 535008 China

The failure of a drilling pump is always due to the break of the drilling pump valve, which is one of the most important but also the weakest parts of the drilling pump. Over the decades, the degradation of drilling pump valves has been investigated extensively and various failure mechanisms have been proposed. However, no experimental test on the fluid has been successfully performed to support some of these mechanisms. In this paper, tests of the flow within the valve play are carried out to investigate the factors resulting in the failure of the valve. In the tests, particle image velocimetry（PIV） technology is employed to measure the flow field distribution of the valve play in the model. From these tests, the distributions of velocity and vorticity of fluid in ＇various valves with different valve angles and different valve lifts are obtained, from which the features of flow fields are derived and generalized. Subsequently, a general rule of the influence of valve angles and valve lifts on the flow velocity is concluded according to chart analyses of maximal velocities and mean velocities. Finally, an analysis is made on the possibility of valve failure caused by erosion and abrasion in a working valve, with the application of the failure mechanisms of drilling pump valves. PIV measurement improves the study on the failure of the drilling pump valve, and the results show good agreement with previous computational fluid dynamics（CFD） simulations.

关键词： drilling pump valve flow field particle image velocimetry(PIV) valve failure

Structural total least squares algorithm for locating multiple disjoint sources based on AOA/TOA/FOA in the presence of system error

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Frontiers of Information Technology & Electronic Engineering 2018年第7期19卷 917-936页

作者： xin CHEN Ding WANG Rui-rui LIU Jie-xin yin ying WU National Digital Switching System Engineering and Technology Research Center Zheng'zhou 450002 China Zhengzhou Institute of Information Science and Technology Zheng'zhou 450002 China

Single-station passive localization technology avoids the complex time synchronization and information exchange between multiple observatories, and is increasingly important in electronic warfare. Based on a single moving station localization system, a new method with high localization precision and numerical stability is proposed when the measurements from multiple disjoint sources are subject to the same station position and velocity displacement. According to the available measurements including the angle-of-arrival(AOA), time-of-arrival(TOA), and frequency-of-arrival(FOA), the corresponding pseudo linear equations are deduced. Based on this, a structural total least squares(STLS) optimization model is developed and the inverse iteration algorithm is used to obtain the stationary target location. The localization performance of the STLS localization algorithm is derived, and it is strictly proved that the theoretical performance of the STLS method is consistent with that of the constrained total least squares method under first-order error analysis, both of which can achieve the Cramér-Rao lower bound accuracy. Simulation results show the validity of the theoretical derivation and superiority of the new algorithm.

关键词： Single-station Structural total least squares Inverse iteration Angle-of-arrival (AOA) Time-of-arrival (TOA) Frequency-of-arrival (FOA) Disjoint sources

Typology and working mechanism of a hybrid power router based on power-frequency transformer electromagnetic coupling with converters

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Protection and Control of Modern Power Systems 2023年第3期8卷 80-96页

作者： Jinmu Lai xin yin Xianggen yin Jiaxuan Hu Fan Xiao School of Electrical and Information Engineering Zhengzhou UniversityZhengzhou 450001Henan ProvincePeople’s Republic of China School of Automation Wuhan University of TechnologyWuhan 430070Hubei ProvincePeople’s Republic of China School of Electrical and Electronic Engineering Huazhong University of Science and Technology(HUST)Wuhan 430074Hubei ProvincePeople’s Republic of China State Grid Hubei Electric Power Research Institute Wuhan 430077Hubei ProvincePeople’s Republic of China

The power router(PR)is a promising piece of equipment for realizing multi-voltage level interconnection and flex-ible power control in the future distribution power *** this paper,a hybrid PR(HPR)topology based on power-frequency transformer electromagnetic coupling with converters is proposed for the medium distribution power *** power-frequency transformer is used to undertake power transmission,voltage conversion,and other main tasks,while the power electronic converters are combined to achieve active *** magnetic and electrical circuit models are established to help discuss the operating principle of the proposed ***,the power flow and control principle of the HPR in different operating conditions are analyzed,with the control system design scheme *** theoretical analysis results are verified by MATLAB/Simulink+Plecs simulation and a controller hardware-in-the-loop study,as well as a down-scale experimental test,indicating that the proposed HPR is flexible in active voltage support and current control.

关键词： Power router Power-frequency transformer Power electronic converter Hybrid Working mechanism

Sr2+-doped rhombohedral LiHf2(PO4)3 solid electrolyte for allsolid-state Li-metal battery

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Rare Metals 2020年第9期39卷 1092-1098页

作者： Qing-Hui Li Chang Xu Bing Huang xin yin College of Electrical and Information Engineering Hunan UniversityChangsha 410082China State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China School of Materials Science and Engineering Tianjin UniversityTianjin 300072China

Solid-state electrolytes in rechargeable all-solidstate Li-metal batteries,which have better safety and higher specific capacity than conventional rechargeable Liion batteries with liquid electrolytes,are limited by the low Li-ion conductivity of the solid electrolyte and the large electrolyte/electrode interfacial ***,we report a new rhombohedral NAS ICON structure Li1.4Sr0.2Hf1.8(PO4)3 with a high Li-ion conductivity of 1.62×10-5 S·cm-1 at 25℃,and its conductivity can be improved to 3.4×10-5 S·cm-1 after the densification of the pellet by hot ***1.4Sr0.2Hf1.8(PO4)3 coated by a thin layer of polymer electrolyte showed a stable lowimpedance dendrite-free plating/stripping process in a symmetric Li/Li cell for 100 h;moreover,the Li1.4Sr0.2Hf1.8(PO4)3 electrolyte had a small interfacial resistance in all-solid-state Li/LiFePO4 cell,which allows a high Coulombic efficiency and good cycling of the cell.

关键词： Solid-state electrolyte NASICON Rhombohedral phase Interfacial resistance All-solid-state battery