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Journal of Rare Earths 2019年第4期37卷 350-355页

作者： Yuanhong Liu Yuan Xue Ronghui Liu Mingyue Chen Guantong Chen Chunpei Yan Xia Zhang Yu'nan Zhou Wei Gao Xiaole Ma National Engineering Research Center for Rare Earth Materials General Research Institute for Nonferrous Metals Grirem Advanced Materials Co.Ltd.

A novel white-light emitting single-phase phosphor La_3 Si_6 N_(11):Dy^(3+),exhibiting two emission peaks centering at 475 and 575 nm, was prepared via conventional solid-state reactions. The structure and morphology of La_3 Si_6 N_(11):Dy^(3+)/Tb^(3+) were investigated by X-ray diffraction(XRD) and scanning electron microscopy(SEM). The emission colors can be tuned from white to yellow-green through increasing the Tb^(3+) concentration in La_3 Si_6 N_(11):Dy^(3+),Tb^(3+), The mechanism of energy transfer(ET) from Dy^(3+) to Tb^(3+) is confirmed according to the excitation,emission spectra and decay lifetimes curve. The temperaturedependent luminescence measurements of La_(2.83)Si_6 N_(11):0.1 Dy^(3+),0.07 Tb^(3+) were also performed, and a good thermal stability is shown, suggesting superior properties for the application as white lightemitting diodes(w-LEDs) phosphor.

关键词： single-phase White emission Energy transfer Rare earths

Performance Enhancement of single-phase Immersion Liquid-Cooled Data Center Servers

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Journal of Thermal Science 2024年第5期33卷 1757-1772页

作者： GE Junlei XIA Feifan ZHANG Chengbin HUANG Yongping School of Energy and Environment Southeast UniversityNanjing 210096China Wuhan Digital Engineering Research Institute Wuhan 430205China

As the promising cooling method for the next generation of data centers,the internal heat transport mechanism and enhancement mechanism of single-phase immersion liquid-cooled(SPILC)systems are not yet well *** address this,a steady-state three-dimensional numerical model is constructed herein to analyze flow and thermal transport capacities in servers using SPILC and traditional air-cooling ***,this paper emphasizes the influence of component positioning,and underscores the benefits of optimizing coolant flow distribution using *** results indicate that the SPILC system outperforms the traditional air-cooling approach at the same inlet Reynolds number(Re).When Re=10000,the SPILC method reduces the maximum temperature by up to 70.13%,increases the average convective heat transfer coefficient by287.5%,and provides better overall thermal uniformity in data center ***,placing devices downstream of high-power components creates"thermal barriers"and degrades thermal transport for upstream devices due to increased flow *** spacing between high-power devices can lead to the formation of bypass channels,further deteriorating heat ***,the addition of baffles in the inlet section of SPILC systems effectively enhances heat dissipation *** maximize the heat dissipation capacity,minimizing bypass channels and optimizing the flow distribution of coolants are crucial.

关键词： single-phase immersion liquid-cooled performance enhancement data center

Effective anisotropy and coercivity in nanocrystalline single-phase NdFeB permanent magnetic material

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Science China(Physics,Mechanics & Astronomy) 2003年第4期46卷 398-404页

作者：韩广兵高汝伟冯维存刘汉强王标张鹏陈伟李卫郭永权 School of Physics and Microelectronics Shandong University Jinan 250100 China

The effect of exchange-coupling interaction on the effective anisotropy and its varying tendency in nanocrystalline single-phase NdFeB permanent magnetic material have been investigated. The results show that the exchange-coupling interaction between grains makes the effective anisotropy of material, Keff, decrease with the reduction of grain size. The variation of Keff is basically the same as that of coercivity. The decrease in effective anisotropy is the main reason of the reduction of coercivity for nanocrystalline single-phase NdFeB permanent magnetic material. In order to get high anisotropy and coercivity in nanocrystalline single-phase NdFeB permanent material, the grain size should be larger than 35 nm.

关键词： nanocrystalline single-phase permanent magnetic material, exchange-coupling interaction, effective anisotropy, coercivity

Electro-triggered Joule heating method to synthesize single-phase CuNi nano-alloy catalyst for efficient electrocatalytic nitrate reduction toward ammonia

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Nano Research 2023年第5期16卷 6632-6641页

作者： Zunjie Zhang Yang Liu Xiaozhi Su Ziwei Zhao Zhenkun Mo Chenyi Wang Yaling Zhao Ye Chen Shuyan Gao School of Chemistry and Chemical Engineering Henan Normal UniversityXinxiang 453007China School of Materials Science and Engineering Henan Normal UniversityXinxiang 453007China Shanghai Synchrotron Radiation Facility Shanghai Institute of Applied PhysicsChinese Academy of SciencesShanghai 201204China

Electrochemical nitrate reduction reaction(NO_(3)RR)has great potential for ammonia(NH_(3))synthesis benefiting from its environmental friendliness and ***-based alloys with elemental diversity and adsorption tunability are widely used as electrocatalyst to lower the reaction overpotential for NO_(3)RR ***,phase separation commonly found in alloys leads to uneven distribution of elements,which limits the possibility of further optimizing the catalytic ***,an electrotriggered Joule heating method,possessing unique superiority of flash heating and cooling that lead to well-dispersed nanoparticles and uniform mixing of various elements,was adopted to synthesize a single-phase CuNi nano-alloy catalyst evenly dispersed on carbon fiber paper,CFP-Cu_(1)Ni_(1),which exhibited a more positive NO_(3)RR initial potential of 0.1 V versus reversible hydrogen electrode(***)than that of pure copper nanoparticles at 10 mA·cm^(−2)in 0.5 mol·L^(−1)Na_(2)SO_(4)+0.1 mol·L^(−1)KNO_(3)***,CFP-Cu_(1)Ni_(1) presented high electrocatalytic activity with a Faradaic efficiency of 95.7%and NH_(3)yield rate of 180.58μmol·h^(−1)·cm^(−2)(2550μmol·h^(−1)·mg_(cat)^(−1))at−0.22 V *** calculations showed that alloying Cu with Ni into single-phase caused an upshift of its d-band center,which promoted the adsorption of NO_(3)−and weakened the adsorption of NH_(3).Moreover,the competitive adsorption of hydrogen ions was restrained until−0.24 *** work offers a rational design concept with clear guidance for rapid synthesis of uniformly dispersed single-phase nano-alloy catalyst for efficient electrochemical NO_(3)RR toward ammonia.

关键词： ammonia nitrate reduction reaction CuNi nano-alloy single-phase adsorption energy

A quasi single-phase model for debris flows and its comparison with a two-phase model

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Journal of Mountain Science 2018年第5期15卷 1071-1089页

作者： XIA Chun-chen LI Ji CAO Zhi-xian LIU Qing-quan HU Kai-heng State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Department of Mechanics School of Aerospace Engineering Beijing Institute of Technology Institute of Mountain Hazards and Environment Chinese Academy of Sciences

A depth-averaged quasi single-phase mixture model is proposed for debris flows over inclined bed slopes based on the shallow water hydrosediment-morphodynamic theory with multi grain sizes. The stresses due to fluctuations are incorporated based on analogy to turbulent flows, as estimated using the depth-averaged k-? turbulence model and a modification component. A fully conservative numerical algorithm, using wellbalanced slope limited centred scheme, is deployed to solve the governing equations. The present quasi single-phase model using four closure relationships for the bed shear stresses is evaluated against USGS experimental debris flow and compared with traditional quasi single-phase models and a recent physically enhanced two-phase model. It is found that the present quasi single-phase model performs much better than the traditional models, and is attractive in terms of computational cost while the two-phase model performs even better appreciably.

关键词： Debris flows Quasi single-phase mixturemodel Stresses due to fluctuations Well-balanced

Dynamic behavior of coalbed methane flow along the annulus of single-phase production

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International Journal of Coal Science & Technology 2019年第4期6卷 547-555页

作者： Xinfu Liu Chunhua Liu Guoqiang Liu School of Mechanical and Automotive Engineering Qingdao University of TechnologyQingdao 266520ShandongChina Key Lab of Industrial Fluid Energy Conservation and Pollution Control(Qingdao University of Technology) Ministry of EducationQingdao 266520ShandongChina College of Mechanical and Electronic Engineering China University of Petroleum(East China)Qingdao 266580ShandongChina PetroChina Coalbed Methane Co. Ltd.Linfen BranchTaiyuan 041000ShanxiChina

Dynamic behavior of coalbed methane (CBM) flow will provide the theoretical basis to optimize production performance for a given well.A mathematical model is developed to simulate flowing pressures and pressure drops of CBM column from well head to bottom *** measured parameters and independent variables of flow rates,flowing pressures and temperatures are involved in CBM producing process along the *** developed relationships are validated against full-scale measured data in single-phase CBM *** proposed methodology can analyze the dynamic behavior in CBM reservoir and process of CBM flow with an overall accuracy of 2%.The calculating process of flowing pressures involves friction factor with variable Reynolds number and CBM temperature and compressibility factor with gravitational *** results showed that the effect of flowing pressure on CBM column was more obvious than that on CBM and water column accompanied by an increase of dynamic water *** ratios of flowing pressure on increment of CBM column to the whole column increased with the declined flow rates of water ***-hole pressure declined with the decreased flowing pressure of CBM column along the *** will lead to the results of the increased pressure drop of CBM column and CBM flow rate in single-phase CBM wellbores.

关键词： Dynamic characteristic single-phase CBM wellbore Flowing pressure of CBM column Flow rate of CBM column

The Use of single-phase Immersion Cooling by Using Two Types of Dielectric Fluid for Data Center Energy Savings

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Energy Engineering 2022年第1期119卷 275-286页

作者： Nugroho Agung Pambudi Awibi Muhamad Yusuf Alfan Sarifudin Energy and Society Laboratory Mechanical Engineering EducationUniversitas Sebelas MaretSurakarta57126Indonesia

Data centers are recognized as one of the most important aspects of the fourth industrial revolution since conventional data centers are inefficient and have dependency on high energy consumption,in which the cooling is responsible for 40%of the ***,this research proposes the immersion cooling method to solving the high energy consumption of data centers by cooling its component using two types of dielectric *** stages of experimentalmethods are used,such as fluid types,cooling effectiveness,optimization,and ***,benchmark software is used to measure the CPU maximum work with the temperature data performed for 24 *** results of this study show that the immersion cooling reduces 13℃ lower temperature than the conventional cooling method which means it saves more energy consumption in the data *** most optimum variable used to decrease the temperature is 1.5 lpm of flow rate and 800 rpm of fan ***,the cooling performance of the dielectric fluids shows that the mineral oil(MO)is better than the virgin coconut oil(VCO).In durability experiment,there are no components damage after five months immersed in the fluid.

关键词： single-phase immersion cooling data center dielectric fluid mineral oil virgin coconut oil

Microstructure,mechanical property and in vitro biocorrosion behavior of single-phase biodegradable Mg-1.5Zn-0.6Zr alloy

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Journal of Magnesium and Alloys 2014年第2期2卷 181-189页

作者： Tao Li Yong He Hailong Zhang Xitao Wang State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China

The microstructure,mechanical property,and in vitro biocorrosion behavior of as-cast single-phase biodegradable Mg-1.5Zn-0.6Zr alloy were investigated and compared with a commercial as-cast AZ91D *** results show that the Mg-1.5Zn-0.6Zr alloy had a single-phase solid solution structure,with an average grain size of 34.7±13.1μ*** alloy exhibited ultimate tensile strength of 168±2.0 MPa,yield strength of 83±0.6 MPa,and elongation of 9.1±0.6%.Immersion tests and electrochemical measurements reveal that the alloy displayed lower biocorrosion rate and more uniform corrosion mode than AZ91D in Hank's *** elimination of intensive galvanic corrosion reactions and the formation of a much more compact and uniform corrosion film mainly account for the better biocorrosion properties of the Mg-1.5Zn-0.6Zr alloy than AZ91D.

关键词： Magnesium alloys Biomaterials single-phase Microstructure Corrosion Biodegradable

Tailoring Sr_(2)Fe_(1.5)Mo_(0.5)O_(6-δ)with Sc as a new single-phase cathode for proton-conducting solid oxide fuel cells

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Science China Materials 2022年第6期65卷 1485-1494页

作者： Liling Zhang Yanru Yin Yangsen Xu Shoufu Yu Lei Bi School of Resource Environment and Safety Engineering University of South ChinaHengyang 421001China

Sc-doped Sr_(2)Fe_(1.5)Mo_(0.5)O_(6-δ)(SFMSc)was successfully synthesized by partially substituting Mo in Sr_(2)Fe_(1.5)Mo_(0.5)O_(6-δ)(SFM)with Sc,resulting in a higher proton diffusion rate in the resultant SFMSc *** calculations showed that doping Sc into SFM lowered the oxygen vacancy formation energy,reduced the energy barrier for proton migration in the oxide,and increased the catalytic activity for oxygen reduction ***,a proton-conducting solid oxide fuel cell(H-SOFC)with a single-phase SFMSc cathode demonstrated significantly higher cell performance than that of cell based on an Sc-free SFM cathode,achieving 1258 mW cm^(−2)at 700℃.The performance also outperformed that of many other H-SOFCs based on single-phase cobalt-free ***,no trade-off between fuel cell performance and material stability was *** SFMSc material demonstrated good stability in both the CO_(2)-containing atmosphere and the fuel cell *** combination of high performance and outstanding stability suggests that SFMSc is an excellent cathode material for H-SOFCs.

关键词： Sr_(2)Fe_(1.5)Mo_(0.5)O_(6-δ) cathode single-phase proton-conducting oxides solid oxide fuel cells

A 6-switch single-phase 5-level current-source inverter

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第6期7卷 1051-1055页

作者： BAO Jian-yu LI Yu-ling ZHANG Zhong-chao School of Electrical Engineering Zhejiang University Hangzhou 310027 China

The new 6-switch single-phase 5-level current-source inverter proposed in this paper was developed by properly simplifying the traditional 8-switch single-phase 5-level current-source inverter, and its operational principle was analyzed. Just like the problem of voltage-unbalance between different levels existing in voltage-source multilevel inverters, a similar problem of current-unbalance between different levels whether for the 8-switch single-phase 5-level current-source inverter, or for the new 6-switch 5-level current-source inverter also exists. A simple current-balance control method via DC current feedback is presented here to implement the current-balance control between different levels. And to reduce the output current harmonics, PWM control technique was used. Simulation and experimental results showed that this new 6-switch topology operates correctly and that the balance-inductor can almost equally distribute the total DC current.

关键词： single-phase Current-source inverter (CSI) Multilevel Topology