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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 sustainability.Cu-based alloys with elemental diversity and adsorption tunability are widely used as electrocatalyst to lower the reaction overpotential for NO_(3)RR catalysis.However,phase separation commonly found in alloys leads to uneven distribution of elements,which limits the possibility of further optimizing the catalytic activity.Herein,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(vs.RHE)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)solution.Importantly,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 vs.RHE.Theoretical 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 V.This 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

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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 usage.Therefore,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 fluids.Four stages of experimentalmethods are used,such as fluid types,cooling effectiveness,optimization,and durability.Furthermore,benchmark software is used to measure the CPU maximum work with the temperature data performed for 24 h.The 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 center.The most optimum variable used to decrease the temperature is 1.5 lpm of flow rate and 800 rpm of fan rotation.Furthermore,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

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White-light emitting single-phase phosphor La_3Si_6N_(11):Dy^(3+),Tb^(3+):Color tunable emission, thermal stability and energy transfer process

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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

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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 hole.The measured parameters and independent variables of flow rates,flowing pressures and temperatures are involved in CBM producing process along the annulus.The developed relationships are validated against full-scale measured data in single-phase CBM wellbores.The 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 gradients.The 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 level.The ratios of flowing pressure on increment of CBM column to the whole column increased with the declined flow rates of water column.Bottom-hole pressure declined with the decreased flowing pressure of CBM column along the annulus.It 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

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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

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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

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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 alloy.The 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±13.1μm.The 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 solution.The 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

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Mixture Regression-Cum-Ratio Estimator Using Multi-Auxiliary Variables and Attributes in single-phase Sampling

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Open Journal of Statistics 2014年第5期4卷 367-376页

作者： Teresio Mutembei John Kung’u Christopher Ouma Department of Statistics and Actuarial Science Kenyatta University Nairobi Kenya

In this paper, we have proposed a class of mixture regression-cum-ratio estimator for estimating population mean by using information on multiple auxiliary variables and attributes simultaneously in single-phase sampling and analyzed the properties of the estimator. An empirical was carried out to compare the performance of the proposed estimator with the existing estimators of finite population mean using simulated population. It was found that the mixture regression-cum-ratio estimator was more efficient than ratio and regression estimators using one auxiliary variable and attribute, ratio and regression estimators using multiple auxiliary variables and attributes and regression-cum-ratio estimators using multiple auxiliary variables and attributes in single-phase sampling for finite population.

关键词： Regression-Cum-Ratio Estimator Multiple Auxiliary Variables and Attributes single-phase Sampling

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Three-phase STATCOM based on a single-phase current source inverter

Three-phase STATCOM based on a single-phase current source i...

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2011 2nd International Conference on Advances in Energy Engineering(ICAEE)

作者： Natalia M.R.Santos V.Fernao Pires Escola Sup.Tecnologia Setubal/Inst.

This paper presents a three-phase STATic synchronous COMpensator（STATCOM） based on a current source inverter.Instead of the typical three-phase current bridge inverter it is used a power converter topology with only a single-phase current bridge inverter.A dynamic model of the STATCOM in αβ coordinates is used as a basis for control design.The control system uses a cascade structure where a fast ac current inner loop and a slow dc current control outer loop is used.For the inner loop,is used a sliding mode technique to generate αβ space-vector modulation.This fast and robust controller the ac currents of the STATCOM are actively shaped,being possible to maintain the desired currents even with high ripple DC inductor current.For the outer loop,is used a PI controller.Computer simulations are presented allowing validating the proposed STATCOM and their control system.

关键词： STATCOM current source inverter single-phase sliding mode controller

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Site occupation and energy transfer in full color emitting phosphor Ba2Ca(BO3)2:Ce3+(K+),Eu^(2+),Mn2+

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Journal of Rare Earths 2022年第11期40卷 1691-1698,I0002页

作者： Qingsong Hu Zaifa Pan Guijie Liang Hubei Key Laboratory of Low Dimensional Optoelectronic Materials and Devices Hubei University of Arts and ScienceXiangyang 441053China College of Chemical Engineering Zhejiang University of TechnologyHangzhou 310014China

White light-emitting diodes(WLEDs)fabricated by single-phase full color emitting phosphor are an emerging solution for health lighting.The crystallographic site occupation of activators in a proper host lattice is crucial for sophisticated design of such phosphor.Here,we report a high quality white lightemitting phosphor Ba_(2)Ca(BO_(3))_(2):Ce^(3+)(K^(+)),Eu^(2+),Mn^(2+)with spectral distribution covering whole visible region.Blue light emission originates from Ce3+ions occupying preferentially Ba^(2+)site by controlling synthesis conditions.Green and red lights are obtained from Eu^(2+)occupying Ba2+(and Ca)site and Mn2+occupying Casite,respectively.In this triple-doped phosphor,strong red emission with a low concentration of Mn2+is realized by the efficient energy transfer from Ce3+and Euto Mn.Furthermore,high quality white light is accomplished by properly tuning the relative doping amount of Ce^(3+)(K^(+))/Eu^(2+)/Mn^(2+)based on efficient simultaneous energy transfer.The results indicate that Ba_(2)Ca(BO_(3))_(2):Ce^(3+)(K^(+)),Eu^(2+),Mn^(2+)is a promising white light-emitting phosphor in WLEDs application.

关键词： single-phase Full color phosphor Site preference occupation Energy transfer Ba2Ca(BO3)2:Ce3+(K+) Eu^(2+) Mn2+ Rare earths

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