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Langmuir Probe and Optical Emission Spectroscopy Studies of Low-Pressure Gas Mixture of CO_2 and N_2

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Plasma Science and Technology 2010年第3期12卷 314-319页

作者： E.F.MENDEZ-martinez P.G.REYES D.OSORIO-GONZALEZ F.CASTILLO h.martinez Faculty of Sciences Autonomous University of the State of Mexico Institute of Nuclear Sciences Autonomous National University of Mexico Institute of Physical Sciences Autonomous National University of Mexico

Optical emission spectroscopy was used to study a gas mixture glow discharge of CO2 and N2 at a total pressure of 1.2 Torr, a power of 100 W and a flow of 16.5 L/min. The emission bands were measured in the wavelength range of 200 nm to 900 nm. The principal species observed were O2^＋（A^2П→ X^2П）, CO^＋（A^2П→X^2∑）, N2^＋（B^2∑u＋ → X^2∑g^＋）, CO2^＋（A^2∏ → X^2∏）, N2（C^3∏u → B^3∏g）, O2（b^1∑g^＋→ X^3∑g^-）, and CO （a^r3∑→a^3∏）. The behavior of the band intensities as a function of the N2 percentage is consistent with recent Monte Carlo simulations. The electron temperature and ion density were determined by a double Langmuir probe. The electron temperature was found in the range of 1.55 eV to 2.93 eV, and the electron concentration in the order of 10^10 cm^-3. The electron temperature and ion density at pure N2 and pure CO2 agree with previous measurements.

关键词： optical emission spectroscopy glow discharge electron temperature CO2 N2

Early Phases of Star Formation: Testing Chemical Tools

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Research in Astronomy and Astrophysics 2024年第1期24卷 96-118页

作者： N.C.martinez S.Paron CONICET-Universidad de Buenos Aires.Instituto de Astronomía y Física del Espacio Ciudad Universitaria(C1428EGA)Ciudad Autónoma de Buenos AiresArgentina

Star-forming processes strongly influence the ISM ***,many high-quality databases are available at millimeter *** them,it is possible to carry out studies that review and deepen previous *** these studies involve large samples of sources,it is preferred to use direct tools to study the molecular *** the aim of testing these tools such as the use of the hCN/hNC ratio as a thermometer,and the use of h^(13)CO^(+),hC_(3)N,N_(2)h^(+) and C_(2)h as "chemical clocks," we present a molecular line study toward 55 sources representing massive young stellar objects at different evolutionary stages:infrared dark clouds(IRDCs),highmass protostellar objects(hMPOs),hot molecular cores(hMCs) and ultracompact h II *** found that the use of the hCN/hNC ratio as a universal thermometer in the ISM should be taken with care because the hCN optical depth is a big issue that can affect the ***,this tool should be utilized only after a careful analysis of the hCN spectrum,checking that no line,neither the main nor the hyperfine ones,presents absorption *** point out that the analysis of the emission of h^(13)CO^(+),hC_(3)N,N_(2)h^(+) and C_(2)h could be useful to trace and distinguish regions among IRDCs,hMPOs and *** molecular line widths of these four species increase from the IRDC to the hMC stage,which can be a consequence of the gas dynamics related to the starforming processes taking place in the molecular *** results not only contribute with more statistics,acting as a probe of such chemical tools,useful to obtain information in large samples of sources,but also complement previous works through the analysis of other types of sources.

关键词： stars:formation ISM:molecules ISM:clouds

Oxide-supported metal catalysts for anaerobic NAD+regeneration with concurrent hydrogen production

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Chinese Chemical Letters 2024年第2期35卷 263-267页

作者： Jianwei Li Joseph W.h.Burnett Claudia martinez Macias Russell F.howe Xiaodong Wang Chemical Engineering School of EngineeringLancaster UniversityLancaster LA1 4YWUnited Kingdom Chemistry Department University of AberdeenAberdeen AB24 3UEUnited Kingdom

We report SiO_(2)-supported monometallic Pt,Pd,Au,Ni,Cu and Co catalysts for proton-driven NAD+regeneration,co-producing h_(2).All metals are fully selective to NAD+where the order of turnover frequencies(Pt>Pd>Cu>Au,Ni and Co)coincides with those otherwise observed in electrochemical hydrogen evolution *** has revealed that NADh is capable of converting the metal sites into a“cathode”without an external potential and the NADh to NAD+reaction involves transferring electron and hydrogen atom ***-deficient Ptδ+(on CeO_(2))enhances TOF and the heterogeneous Pt/CeO_(2) catalyst is recyclable without losing any activity/selectivity.

关键词： NAD+regeneration heterogeneous catalyst hydrogenase mimic hydrogen binding energy hydrogen production

Comparison between Liver Cancer Mortality Rates in China and Spain

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Journal of Clinical and Translational hepatology 2024年第10期12卷 831-833页

作者： Javier Guinea-Castanares Jesus Maria Iturralde Iriso Irune Natalia Elizondo Pinillos Gloria martinez Iniesta Osakidetza Basque health Service Ringgold Standard Institution(16651) Vitoria-GasteizSpain

Dear Editors,We have read with interest the article by Liu h et al.1 published in your journal regarding liver cancer mortality in China and would like to compare it with that of our country,Spain,which is a European ... 详细信息

关键词： al. mortality Cancer

Free vibration and buckling analysis of polymeric composite beams reinforced by functionally graded bamboo fbers

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 543-562页

作者： h.M.FEIZABAD M.h.YAS Department of Mechanical Engineering Razi UniversityKermanshah ***Iran

Natural fibers have been extensively researched as reinforcement materials in polymers on account of their environmental and economic advantages in comparison with synthetic fibers in the recent *** fibers are renowned for their good mechanical properties,abundance,and short cycle *** beams are one of the fundamental structural components and are susceptible to mechanical loads in engineering applications,this paper performs a study on the free vibration and buckling responses of bamboo fiber reinforced composite(BFRC)beams on the elastic *** different functionally graded(FG)layouts and a uniform one are the considered distributions for unidirectional long bamboo fibers across the *** elastic properties of the composite are determined with the law of *** hamilton’s principle,the governing equations of motion are *** generalized differential quadrature method(GDQM)is then applied to the equations to obtain the *** achieved outcomes exhibit that the natural frequency and buckling load values vary as the fiber volume fractions and distributions,elastic foundation stiffness values,and boundary conditions(BCs)and slenderness ratio of the beam ***,a comparative study is conducted between the derived analysis outcomes for BFRC and homogenous polymer beams to examine the effectiveness of bamboo fibers as reinforcement materials,demonstrating the significant enhancements in both vibration and buckling responses,with the exception of natural frequencies for cantilever beams on the Pasternak foundation with the FG-◇fiber ***,the obtained analysis results of BFRC beams are also compared with those for carbon nanotube reinforced composite(CNTRC)beams found in the literature,indicating that the buckling loads and natural frequencies of BFRC beams are lower than those of CNTRC beams.

关键词： bamboo fiber free vibration buckling analysis functionally graded(FG)beam elastic foundation generalized differential quadrature method(GDQM)

holographic dark energy in non-conserved gravity theory

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Communications in Theoretical Physics 2024年第4期76卷 126-133页

作者： h R Fazlollahi Institute of Gravitation and Cosmology Peoples Friendship University of Russia(RUDN University)6 Miklukho-Maklaya StMoscow117198Russia

Recently, reconsidering the Rastall idea T_(μ;νν)^(v)=α_(,μ) through relativistic thermodynamics gives a new form for the scalar field α which led us to construct modern modified theory of gravity debugged ‘non-conserved gravity theory’ Fazlollahi 2023 Euro. Phys. J. C 83 923. This theory unlike other modified theories of gravity cannot directly explain the current acceleration expansion in the absence of the cosmological constant and or existence of other forms of dark energy. hence, in this study we have reinvestigated holographic dark energy Ρ_(X)~h^(2) in the non-conserved theory of gravity. In this context, the density and pressure of dark energy depend on the non-conserved term and density of the dust matter field. As shown, due to non-conservation effects on large-scale structures, unlike the original holographic model, our model onsets an acceleration epoch for the current Universe satisfies observations. Moreover, the interaction and viscous scenarios are studied for this model.

关键词： non-conserved gravity covariant form of thermodynamics holographic dark energy

Novel synthesis of stabilized Bi1-x-yGdxDyyO1.5 solid electrolytes with enhanced conductivity for intermediate temperature solid oxide fuel cells（SOFCs）

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Journal of Rare Earths 2024年第10期42卷 1903-1911页

作者： Ahmed h.Ibrahim Yehia M.Abbas h.A.Ayoub Marwa h.Ali Mustafa Aldoori Materials Science Laboratory Physics DepartmentFaculty of ScienceSuez Canal University Ministry of higher Education and Scientific Research Aliraqia University

herein,we report the synthesis of a Dy-Gd co-doped cubic phase-stabilized Bi2O3solid electrolyte system via solid-state processing under atmospheric *** with Dy3+and Gd3+has been observed to significantly enhance the densification process during sintering for stabilization purposes,thereby improving the electrical properties of δ-Bi2O3-type *** synthesized ceramics were characterized using X-ray diffraction（XRD）,field emission scanning electron microscopy-energy dispersive X-ray spectroscopy（FESEM-EDX）,thermal gravimetry/differential thermal analysis（TG/DTA）,and the four-point probe technique（4PPT）.XRD analysis reveals that the samples Bi1-x-yGdxDyyO1.5（y=0.05/x=0.05,0.10,0,15,and 0.20,and x=0.05/y=0.10,0.15,and 0.20） exhibit a stable face-centered cubic δ-phase and a mixed-phase crystallographic *** XRD analysis of the stabilized δ-phase suggests that the prepared oxides show a face-centered cubic（FCC） structure with a space group of *** micrographs reveal that the composition Bi0.90Gd0.05Dy0.05O1.5has no significant ***,an evident increase in the pore formation is observed as the amount of Gd2O3increases until it reaches 20%.This finding suggests that dense pellets are formed during the sintering process at 900-1000℃.The DTA analyses were performed to verify the phase stability,which agrees with the XRD *** electrochemical performance of the synthesized Dy-Gd co-doped Bi2O3solid electrolyte system was evaluated and analyzed in detail by using the electrochemical impedance spectroscopy（EIS） technique,Based on EIS and conductivity measurements,Bi0.75Gd0.20Dy0.05O1.5exhibits the lowest activation energy of 0.519 eV and the highest conductivity value of 0.398 S/cm at 627℃compared to the other samples;this composition can be used as a solid electrolyte for intermediatetemperature solid oxide fuel cells（SOFCs）.

关键词： Electrochemical impedance spectroscopy (EIS) Fast Fourier transform (FFT) Rare earths Rietveld Solid oxide fuel cells (SOFCs) Solid-state processing

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13国儿童青少年水及饮料摄入量调查

13国儿童青少年水及饮料摄入量调查

Convexification of hybrid AC-DC Optimal Power Flow with Line-Commutated Converters

作者： I.Guelinckx C.Ferreira-Pêgo L.A.Moreno S.A.Kavouras J.Gandy h.martinez S.Bardosono M.Abdollahi E.Nasseri A.Jarosz G.Ma E.Carmuega N.Babio J.Salas-Salvadó 何海蓉 hydration and health Department Danone Research

目的描述三个大洲13个国家儿童青少年水和其他饮料的摄入。方法由13个横断面研究中获得3611名4-9岁儿童和8109名10-17岁青少年的数据,其中男性比例为47%。三个国家使用分层整群抽样设计随机抽取学校班级。其他国家使用一种定量方法随机... 详细信息

目的描述三个大洲13个国家儿童青少年水和其他饮料的摄入。方法由13个横断面研究中获得3611名4-9岁儿童和8109名10-17岁青少年的数据,其中男性比例为47%。三个国家使用分层整群抽样设计随机抽取学校班级。其他国家使用一种定量方法随机抽取研究对象。连续7天使用专门的液体记录表获得摄入的液体种类的细节。结果全部样本中,观察得出平均摄入量最高的是水(738±567毫升/天),接下来是牛奶(212±209毫升/天),常见软饮料(RSB)(168±290毫升/天)和果汁(128±228毫升/天)。地理位置接近的国家被发现是摄入水、常见软饮料或热饮居多的模式。大多数国家中,青少年与儿童相比牛奶摄入量显著下降,而常见软饮料和热饮摄入量增加。观察到的最为一致的性别差异是在两个年龄段中男性常见软饮料摄入量显著高于女性。结论总体来看,水是儿童青少年消费量最大的液体,但是实质上不同国家之间其他种类液体的摄入量是不同的。因为常见软饮料的摄入量巨大,在一些国家甚至高于水的摄入量,应该采取措施改善儿童青少年的液体摄入习惯。

关键词：水饮料液体摄入儿童青少年

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 617-628页

作者： hongyuan Liang Zhigang Li J.h.Zheng Q.h.Wu School of Electric Power Engineering South China University of TechnologyGuangzhou 510641China

Line-commutated converter (LCC)-based high-voltage DC (hVDC) systems have been integrated with bulk AC power grids for interregional transmission of renewable power. The nonlinear LCC model brings additional nonconvexity to optimal power flow (OPF) of hybrid AC-DC power grids. A convexification method for the LCC station model could address such nonconvexity but has rarely been discussed. We devise an equivalent reformulation for classical LCC station models that facilitates second-order cone convex relaxation for the OPF of LCC-based AC-DC power grids. We also propose sufficient conditions for exactness of convex relaxation with its proof. Equivalence of the proposed LCC station models and properties, exactness, and effectiveness of convex relaxation are verified using four numerical simulations. Simulation results demonstrate a globally optimal solution of the original OPF can be efficiently obtained from relaxed model.

关键词： AC-DC power system convex relaxation linecommutated converter optimal power flow second-order cone programming