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Journal of Northeast Agricultural University (English Edition) Instruction to Authors
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《Journal of Northeast Agricultural University(English Edition)》 2025年第3期F0003-F0003,共1页
Aims and Scope Journal of Northeast Agricultural University(English Edition)is a comprehensive academic journal on agricultural sciences sponsored by Northeast Agricultural University and distributed worldwide.It is a... Aims and Scope Journal of Northeast Agricultural University(English Edition)is a comprehensive academic journal on agricultural sciences sponsored by Northeast Agricultural University and distributed worldwide.It is a peer reviewed journal published quarterly and mainly publishes review and research articles that reflect the latest achievements on crop science,horticulture,plant protection,resource and environment,animal science,veterinary medicine,agricultural engineering and technology,agricultural water conservancy,life science,biotechnology and food science. 展开更多
关键词 agricultural sciences HORTIcULTURE plant protection review research articles water c crop science peer reviewed journal resource environment
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Simulation of ^(13)C NMR chemical shifts of carbinol carbon atoms using quantitative structure-spectrum relationships 被引量:2
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作者 戴益民 黄可龙 +3 位作者 李浔 曹忠 朱志平 杨道武 《Journal of Central South University》 SCIE EI CAS 2011年第2期323-330,共8页
A quantitative structure-spectrum relationship (QSSR) model was developed to simulate 13C nuclear magnetic resonance (NMR) spectra of carbinol carbon atoms for 55 alcohols. The proposed model,using multiple linear reg... A quantitative structure-spectrum relationship (QSSR) model was developed to simulate 13C nuclear magnetic resonance (NMR) spectra of carbinol carbon atoms for 55 alcohols. The proposed model,using multiple linear regression,contained four descriptors solely extracted from the molecular structure of compounds. The statistical results of the final model show that R2= 0.982 4 and S=0.869 8 (where R is the correlation coefficient and S is the standard deviation). To test its predictive ability,the model was further used to predict the 13C NMR spectra of the carbinol carbon atoms of other nine compounds which were not included in the developed model. The average relative errors are 0.94% and 1.70%,respectively,for the training set and the predictive set. The model is statistically significant and shows good stability for data variation as tested by the leave-one-out (LOO) cross-validation. The comparison with other approaches also reveals good performance of this method. 展开更多
关键词 carbinol carbon atom ^13c nuclear magnetic resonance chemical shift topological indices quantitative structure-spectroscopy relationship
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Corrigendum to“Mechanistic Insights into Water-Mediated CO_(2)Electrochemical Reduction Reactions on Cu@C_(2)N Catalysts:A Theoretical Study”[Acta Physico-Chimica Sinica(2024)40,2303040]
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《物理化学学报》 北大核心 2025年第5期144-144,共1页
Hanyu Xu 1,Xuedan Song 1,*,Qing Zhang 1,Chang Yu 1,Jieshan Qiu 1,2,*1 Liaoning Key Lab for Energy Materials and Chemical Engineering,State Key Laboratory of Fine Chemicals,School of Chemical Engineering,Dalian Univers... Hanyu Xu 1,Xuedan Song 1,*,Qing Zhang 1,Chang Yu 1,Jieshan Qiu 1,2,*1 Liaoning Key Lab for Energy Materials and Chemical Engineering,State Key Laboratory of Fine Chemicals,School of Chemical Engineering,Dalian University of Technology,Dalian 116024,Liaoning Province,China. 展开更多
关键词 chemical engineeringdalian theoretical study water mediated cu c N catalysts fine chemicalsschool cO electrochemical reduction chemical engineeringstate
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细胞色素P450(CYP450)遗传多态性研究进展 被引量:44
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作者 成碟 徐为人 刘昌孝 《中国药理学通报》 CAS CSCD 北大核心 2006年第12期1409-1414,共6页
近年来对CYP450基因型和表型相关性的研究越来越受到重视,从临床合理用药方面来说,人们希望利用基因型分析来了解个体中药物代谢酶的活性,期望既能提高药物治疗水平同时又降低不良反应的发生;从新药研发角度来说,研究药物的代谢酶CYP45... 近年来对CYP450基因型和表型相关性的研究越来越受到重视,从临床合理用药方面来说,人们希望利用基因型分析来了解个体中药物代谢酶的活性,期望既能提高药物治疗水平同时又降低不良反应的发生;从新药研发角度来说,研究药物的代谢酶CYP450的功能能够指导新药的设计、筛选及优化。该文通过查阅国内外相关文献综述了近年来关于CYP450遗传多态性研究的进展,分别介绍了CYP2C19、CYP2C9、CYP3A4、CYP2D6、CYP1A2和CYP2E1这6种主要的药物代谢酶。研究CYP450对新药设计、筛选、评价及优化有重要意义。 展开更多
关键词 细胞色素P450 cYP450 遗传多态性 cYP2c19 cYP2c9 cYP3A4 cYP2D6 cYP1A2 cYP2E1
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RESEARCH ON COUPLED RELATIONSHIP BETWEEN HYDRATION NUMBER WITH RAMAN SPECTRUM
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作者 LEI Huaiyan~(1,2), LIU Zhihong~3, FAN Shuanshi~2, XU Maoquan~1 and GUAN Baocong~1 (~1 Institute of Oceanography and Environment, Xiamen University ~2 Guangzhou Institute of Energy Conversion, CAS ~3 Institute of Chemical Engineering, Xiamen University) 《化工学报》 EI CAS CSCD 北大核心 2003年第z1期41-46,共6页
As we know, there are three structures-sⅠ, sⅡ, and sH, with hydrocarbonate gas hydrate.Because of those special structures characteristics and potentail large fossil energy resource, gas hydrate play an important ro... As we know, there are three structures-sⅠ, sⅡ, and sH, with hydrocarbonate gas hydrate.Because of those special structures characteristics and potentail large fossil energy resource, gas hydrate play an important role in natural carbonate cycle system. In this paper, CH4, CO2, C3H8, and CH4 +CO2 system have been experimental performed in order to model hydrate formation and discomposition and to obtain hydrate stability conditions of tempreature and pressure. The results from laboratory using Raman spectra show that Raman spectrascopy is a effective tool to identify hydrate structure. Raman spectra of clathrate hydrate guest molecules are presented for two structure (sⅠ and sⅡ) in the following systems: CH4, CO2, C3 H8. Relatively occupancy of CH4 in the large and small cavities of sⅠ were determined by deconvoluting the v1 symmetric bands, resulting in hydration numbers of 6.04±0.03. The freqyuency of the v1 bands for CH4 in structures Ⅰ and Ⅱ differ statistically. The large cavities were measured to be almost fully occupied by CH4 and CO2, whereas only a small fraction of the small cavities are occupied by CH4. No CO2 was found in the small cavities. 展开更多
关键词 cH4 cO2 c3H8 cLATHRATE Hydrate RAMAN Spectrum HYDRATION Number
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De novo-design of highly exposed Co−N−C single-atom catalyst for oxygen reduction reaction
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作者 ZHOU Dan ZHU Hongyue +1 位作者 ZHAO Yang LIU Yiming 《燃料化学学报(中英文)》 北大核心 2025年第1期128-137,共10页
The nitrogen-coordinated metal single-atom catalysts(M−N−C SACs)with an ultra-high metal loading synthetized by direct high-temperature pyrolysis have been widely reported.However,most of metal single atoms in these c... The nitrogen-coordinated metal single-atom catalysts(M−N−C SACs)with an ultra-high metal loading synthetized by direct high-temperature pyrolysis have been widely reported.However,most of metal single atoms in these catalysts were buried in the carbon matrix,resulting in a low metal utilization and inaccessibility for adsorption of reactants during the catalytic process.Herein,we reported a facile synthesis based on the hard-soft acid-base(HSAB)theory to fabricate Co single-atom catalysts with highly exposed metal atoms ligated to the external pyridinic-N sites of a nitrogen-doped carbon support.Benefiting from the highly accessible Co active sites,the prepared Co−N−C SAC exhibited a superior oxygen reduction reactivity comparable to that of the commercial Pt/C catalyst,showing a high turnover frequency(TOF)of 0.93 e^(−)·s^(-1)·site^(-1)at 0.85 V vs.RHE,far exceeding those of some representative SACs with a ultra-high metal content.This work provides a rational strategy to design and prepare M−N−C single-atom catalysts featured with high site-accessibility and site-density. 展开更多
关键词 hard-soft acid-base co−N−c single-atom catalyst highly accessible active sites oxygen reduction reaction
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Screening of metal additives in ABS polymer fuel for enhanced performance in hybrid rocket motors:A computational analysis using CEA
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作者 Gail Ndlovu Bilainu Oboirien Patrick Ndungu 《Defence Technology(防务技术)》 2025年第8期176-184,共9页
This study investigates the potential of metal additives in acrylonitrile butadiene styrene(ABS)polymer fuel to enhance hybrid rocket motor(HRM)performance through computational analysis,Chemical Equilibrium with Appl... This study investigates the potential of metal additives in acrylonitrile butadiene styrene(ABS)polymer fuel to enhance hybrid rocket motor(HRM)performance through computational analysis,Chemical Equilibrium with Applications(CEA),software.ABS was selected as the base fuel due to its thermoplastic nature,which allows for the creation of complex fuel geometries through 3D printing,offering significant flexibility in fuel design.Hybrid rockets,which combine a solid fuel with a liquid oxidiser,offer advantages in terms of operational simplicity and safety.However,conventional polymer fuels often exhibit low regression rates and suboptimal combustion efficiencies.In this research,we evaluated a range of metal additives-aluminium(Al),boron(B),nickel(Ni),copper(Cu),and iron(Fe)-at chamber pressures ranging from 1 to 30 bar and oxidiser-to-fuel(O/F)ratios between 1.1 and 12,resulting in 1800 unique test conditions.The main performance parameters used to assess each formulation were characteristic velocity(C^(*))and adiabatic flame temperature.The results revealed that each test produced a different optimum O/F ratio,with most ratios falling between 4 and 6.The highest performance was achieved at a chamber pressure of 30 bar across all formulations.Among the additives,Al and B demonstrated significant potential for improved combustion performance with increasing metal loadings.In contrast,Fe,Cu,and Ni reached optimal performance at a minimum loading of 1%.Future work includes investigating B-Al metal composites as additives into the ABS base polymer fuel,and doing experimental validation tests where the metallised ABS polymer fuel is 3D printed. 展开更多
关键词 Hybrid rocket motors Acrylonitrile butadiene styrene(ABS) Metallised polymer fuels combustion performance characteristic velocity(c*) chemical equilibrium with applications (cEA)
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An executable modeling and analyzing approach to C4ISR architecture 被引量:4
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作者 HE Hongyue ZHU Weixing +1 位作者 LI Ruiyang DENG Qiaoyu 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2020年第1期109-117,共9页
To analyze the behavioral model of the command,control,communication,computer,intelligence,surveillance,reconnaissance(C4ISR)architecture,we propose an executable modeling and analyzing approach to it.First,the meta c... To analyze the behavioral model of the command,control,communication,computer,intelligence,surveillance,reconnaissance(C4ISR)architecture,we propose an executable modeling and analyzing approach to it.First,the meta concept model of the C4ISR architecture is introduced.According to the meta concept model,we construct the executable meta models of the C4ISR architecture by extending the meta models of fUML.Then,we define the concrete syntax and executable activity algebra(EAA)semantics for executable models.The semantics functions are introduced to translating the syntax description of executable models into the item of EAA.To support the execution of models,we propose the executable rules which are the structural operational semantics of EAA.Finally,an area air defense of the C4ISR system is used to illustrate the feasibility of the approach. 展开更多
关键词 cOMMAND control communication computer INTELLIGENcE SURVEILLANcE reconnaissance(c4ISR)architecture meta model executable model algebraic semantics
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YOLOv8n-CSG:轻量化钢材表面缺陷检测算法
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作者 赵佰亭 张敏 贾晓芬 《电子测量与仪器学报》 北大核心 2025年第8期115-125,共11页
为解决钢材表面缺陷检测中因缺陷类型繁多、尺寸差异显著造成检测精度低,以及现有模型复杂度高等问题,提出了一种改进YOLOv8n的轻量化检测算法YOLOv8n-CSG。首先,引入上下文引导模块(context guided block,CG block)设计C2f_CG模块增强... 为解决钢材表面缺陷检测中因缺陷类型繁多、尺寸差异显著造成检测精度低,以及现有模型复杂度高等问题,提出了一种改进YOLOv8n的轻量化检测算法YOLOv8n-CSG。首先,引入上下文引导模块(context guided block,CG block)设计C2f_CG模块增强对周围特征的捕捉能力,增强信息关联性;其次,加入星型网络模块(Star Block)设计出C2f_Star模块,将输入数据映射到高维的非线性特征空间,生成丰富的特征表示,使得模型在处理细微缺陷时更加有效;最后,设计了集成分组混洗卷积(grouped and shuffled convolution,GSConv)和高效多尺度注意力机制(efficient multi-Scale attention,EMA)的轻量化检测头GSE_Detect,保持了原检测头的高效的同时降低复杂度。在NEU-DET数据集上进行多组实验,结果表明,改进后的YOLOv8n-CSG网络模型平均精度均值(mAP)mAP@0.5达到了76.8%,相较于YOLOv8n,mAP@0.5提升了6.9%、精度提升了11.3%、计算量降低了37%、参数量降低了35.2%,展现出对钢材表面缺陷更佳的检测能力,且平衡了模型的性能和复杂度。 展开更多
关键词 缺陷检测 轻量化YOLOv8n c2f_cG c2f_Star GSE_Detect
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Variation of Membrane Electrode Assembly Catalyst Layer in Unitized Regenerative Fuel Cell
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作者 Yollanda Nurcholifah Dedi Rohendi +4 位作者 Edy Herianto Majlan Nirwan Syarif Addy Rachmat Dwi Hawa Yulianti Nyimas Febrika S 《电化学(中英文)》 北大核心 2025年第4期32-43,共12页
A unitized regenerative fuel cell(URFC)is a device that may function reversibly as either a fuel cell(FC)or water elec-trolysis(WE).An important component of this device is the Membrane electrode assembly(MEA).Therefo... A unitized regenerative fuel cell(URFC)is a device that may function reversibly as either a fuel cell(FC)or water elec-trolysis(WE).An important component of this device is the Membrane electrode assembly(MEA).Therefore,this study aimed to compare the performance outcomes of MEA using electrodes with single and three catalyst layers.This study measured Electrochemical Surface Area(ECSA),Electrochemical Impedance Spectroscopy(EIS),X-ray Diffraction analysis(XRD),and X-ray Fluorescence(XRF).Furthermore,the round-trip efficiency(RTE)of the MEA,as w ell as the performance in FC and WE mode,was measured.In comparison,The ECSA values of Pt-Ru/C and Pt/C with three catalyst layers were higher than the single catalyst layer.This result was supported by electrode characterization data for XRD and XRF.The respective electrical conductivity values of Pt-Ru/C and Pt/C with three catalyst layers are also higher than the single cata-lyst layer,and the performance of URFC using MEA with three catalyst layers has the highest value of RTE among the MEA performances of URFC,which is 100%at a current density of 4 mA·cm-2. 展开更多
关键词 Unitized regenerative fuel cell Round trip efficiency Pt-Ru/c Membrane electrode assembly Electrochemical surface area
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Design and Optimization of Anode Catalysts for Direct Ethanol Fuel Cells:Advances and Challenges in C-C bond Activation and Selective Modulation of the C1 Pathway
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作者 Kai-Chi Qin Meng-Tian Huo +3 位作者 Yu Liang Si-Yuan Zhu Zi-Hao Xing Jin-Fa Chang 《电化学(中英文)》 北大核心 2025年第8期1-22,共22页
Direct ethanol fuel cells(DEFCs)are a promising alternative to conventional energy sources,offering high energy density,environmental sustainability,and operational safety.Compared to methanol fuel cells,DEFCs exhibit... Direct ethanol fuel cells(DEFCs)are a promising alternative to conventional energy sources,offering high energy density,environmental sustainability,and operational safety.Compared to methanol fuel cells,DEFCs exhibit lower toxicity and a more mature preparation process.Unlike hydrogen fuel cells,DEFCs provide superior storage and transport feasibility,as well as cost-effectiveness,significantly enhancing their commercial viability.However,the stable C-C bond in ethanol creates a high activation energy barrier,often resulting in incomplete electrooxidation.Current commercial platinum(Pt)-and palladium(Pd)-based catalysts demonstrate low C-C bond cleavage efficiency(<7.5%),severely limiting DEFC energy output and power density.Furthermore,high catalyst costs and insufficient activity impede large-scale commercialization.Recent advances in DEFC anode catalyst design have focused on optimizing material composition and elucidating catalytic mechanisms.This review systematically examines developments in ethanol electrooxidation catalysts over the past five years,highlighting strategies to improve C1 pathway selectivity and C-C bond activation.Key approaches,such as alloying,nanostructure engineering,and interfacial synergy effects,are discussed alongside their mechanistic implications.Finally,we outline current challenges and future prospects for DEFC commercialization. 展开更多
关键词 Direct ethanol fuel cells Ethanol electrooxidation c-c bond cleavage ELEcTROcATALYSIS Anode catalyst
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A framework of force of information influence and application for C4KISR system
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作者 MAO Shaojie DIAO Lianwang +6 位作者 SUN Yu WANG Heng YI Kan XU Xin MAO Xiaobin ZHANG Kecheng SHENG Long 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2024年第2期430-443,共14页
The subversive nature of information war lies not only in the information itself, but also in the circulation and application of information. It has always been a challenge to quantitatively analyze the function and e... The subversive nature of information war lies not only in the information itself, but also in the circulation and application of information. It has always been a challenge to quantitatively analyze the function and effect of information flow through command, control, communications, computer, kill, intelligence,surveillance, reconnaissance (C4KISR) system. In this work, we propose a framework of force of information influence and the methods for calculating the force of information influence between C4KISR nodes of sensing, intelligence processing,decision making and fire attack. Specifically, the basic concept of force of information influence between nodes in C4KISR system is formally proposed and its mathematical definition is provided. Then, based on the information entropy theory, the model of force of information influence between C4KISR system nodes is constructed. Finally, the simulation experiments have been performed under an air defense and attack scenario. The experimental results show that, with the proposed force of information influence framework, we can effectively evaluate the contribution of information circulation through different C4KISR system nodes to the corresponding tasks. Our framework of force of information influence can also serve as an effective tool for the design and dynamic reconfiguration of C4KISR system architecture. 展开更多
关键词 information warfare command control communications computer KILL intelligence surveillance reconnaissance(c4KISR)system information circulation force of information influence information entropy
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弱左C-rpp半群的一个定理(英文)
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作者 李刚 邢斐斐 《科学技术与工程》 2006年第15期2229-2233,共5页
J.B.Fountain1977年定义了Crpp半群,利用半群S上的右Green同余关系,他给出了Crpp半群的一个定理。此文研究弱左Crpp半群,用已得到的左C完全Ehresmanncyber群的结构定理给出此类半群的一个结构定理。弱左C半群的结构定理是此定理的特例。
关键词 c-RPP半群 c-RPP半群 c-半群 弱左c半群 c—Ehresmann cyber群
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18β- glycyrrhetinic acid inhibits apoptosis of renal tubular epithelial cells via enhancing level of BMP-7 epigenetically through targeting HDAC2
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《中国药理学通报》 CAS CSCD 北大核心 2015年第B11期101-102,共2页
Cisplatin (CP) , a highly effective and widely used chemotherapeutic agent, has a major limitation for its nephrotoxicity. We recently identified a novel strategy for attenuating its nephrotoxicity in chemotherapy b... Cisplatin (CP) , a highly effective and widely used chemotherapeutic agent, has a major limitation for its nephrotoxicity. We recently identified a novel strategy for attenuating its nephrotoxicity in chemotherapy by an ef- fective adjuvant via epigenetic modification through targeting Histone deacetylase 2 (HDAC2). Glycyrrhizic acid (GA) ,a major active component of Licorice, was described here for its new application. Molecular docking and Surface Plasmon resonance (SPR) assay firstly reported that 18βGA, GA metabolite in vivo, could directly bind to HDAC2 and prevent HDAC2 activation. The effects and mechanisms of GA and its major metabolite 18βGA were assessed in CP-induced acute kidney injury (AKI) in C57BL/6 mice, and in CP-treated HK-2 and mTEC cells lines. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and flow cytometry (FCM) results confirmed that GA and 18βGA could inhibit apoptosis of renal tubular epithelial cells induced by CP in vivo and in vitro. Western blot and immunofluorescence results demonstrated that the expression of bone morphogenetic protein- 7 (BMP-7) , a protective molecule in renal inflammation, was clearly induced by 18βGA in AKI models while siR- NA BMP-7 could reduce the inhibitory effect of 18βGA on apoptosis. Results of current study indicated that 18βGA inhibited apoptosis of renal tubular epithelial cells via enhancing level of BMP-7 epigenetically through targeting HDAC2, therefore protecting against CP-induced AKI. These available evidence, which led to an improved under- standing of molecular recognition, suggested that 18βGA could serve as a potential clinical adjuvant in chemothera- 展开更多
关键词 acute KIDNEY injury ( AKI ) glycyrrhizic AcID ( cA ) 18β-glycyrrhetinic AcID ( 18βc A ) histonedeacetylase2 (HDAc2) bonemorphogenetic protein-7 ( BMP-7 )
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Direct oxidation of methane at low temperature using Pt/C,Pd/C,Pt/C-ATO and Pd/C-ATO electrocatalysts prepared by sodium borohydride reduction process 被引量:1
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作者 J.Nandenha E.H.Fontes +2 位作者 R.M.Piasentin F.C.Fonseca A.O.Neto 《燃料化学学报》 EI CAS CSCD 北大核心 2018年第9期1137-1145,共9页
The main objective of this paper was to characterize the voltammetric profiles of the Pt/C,Pt/C-ATO,Pd/C and Pd/CATO electrocatalysts and study their catalytic activities for methane oxidation in an acidic electrolyte... The main objective of this paper was to characterize the voltammetric profiles of the Pt/C,Pt/C-ATO,Pd/C and Pd/CATO electrocatalysts and study their catalytic activities for methane oxidation in an acidic electrolyte at 25 ℃ and in a direct methane proton exchange membrane fuel cell at 80 ℃. The electrocatalysts prepared also were characterized by X-ray diffraction( XRD) and transmission electron microscopy( TEM). The diffractograms of the Pt/C and Pt/C-ATO electrocatalysts show four peaks associated with Pt face-centered cubic( fcc) structure,and the diffractograms of Pd/C and Pd/C-ATO show four peaks associated with Pd face-centered cubic( fcc) structure. For Pt/C-ATO and Pd/C-ATO,characteristic peaks of cassiterite( SnO_2) phase are observed,which are associated with Sb-doped SnO_2( ATO) used as supports for electrocatalysts. Cyclic voltammograms( CV) of all electrocatalysts after adsorption of methane show that there is a current increase during the anodic scan. However,this effect is more pronounced for Pt/C-ATO and Pd/C-ATO. This process is related to the oxidation of the adsorbed species through the bifunctional mechanism,where ATO provides oxygenated species for the oxidation of CO or HCO intermediates adsorbed in Pt or Pd sites. From in situ ATR-FTIR( Attenuated Total Reflectance-Fourier Transform Infrared) experiments for all electrocatalysts prepared the formation of HCO or CO intermediates are observed,which indicates the production of carbon dioxide. Polarization curves at 80 ℃in a direct methane fuel cell( DMEFC) show that Pd/C and Pt/C electroacatalysts have superior performance to Pd/C-ATO and Pt/C-ATO in methane oxidation. 展开更多
关键词 sodium BOROHYDRIDE reduction process Pt/c-ATO and Pd/c-ATO ELEcTROcATALYSTS METHANE oxidation acidic electrolytes polarization curves
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Electrocatalytic Nitric Oxide Reduction to Yield Ammonia over Fe_(3)C Nanocrystals
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作者 Sen Lin Lang Zhang +4 位作者 Tong Hou Jun-Yang Ding Zi-Mo Peng Yi-Fan Liu Xi-Jun Liu 《电化学(中英文)》 北大核心 2025年第4期1-11,共11页
Nitric oxide(NO),which generally originates from vehicle exhaust and industrial flue gases,is one of the most serious air pollutants.In this case,the electrochemical NO reduction reaction(NORR)not only removes the atm... Nitric oxide(NO),which generally originates from vehicle exhaust and industrial flue gases,is one of the most serious air pollutants.In this case,the electrochemical NO reduction reaction(NORR)not only removes the atmospheric pollutant NO but also produces valuable ammonia(NH_(3)).Hence,through the synthesis and modification of Fe_(3)C nanocrystal cata-lysts,the as-obtained optimal sample of Fe_(3)C/C-900 was adopted as the NORR catalyst at ambient conditions.As a result,the Fe_(3)C/C-900 catalyst showed an NH_(3)Faraday efficiency of 76.5%and an NH_(3)yield rate of 177.5μmol·h^(-1)·cm^(-2)at the working potentials of-0.8 and-1.2 V versus reversible hydrogen electrode(vs.RHE),respectively.And it delivered a stable NORR activity during the electrolysis.Moreover,we attribute the high NORR properties of Fe_(3)C/C-900 to two aspects:one is the enhanced intrinsic activity of Fe_(3)C nanocrystals,including the lowering of the energy barrier of rate-limiting step(*NOH→*N)and the inhibition of hydrogen evolution;on the other hand,the favorable dispersion of active components,the effective adsorption of gaseous NO,and the release of liquid NH_(3)products facilitated by the porous carbon substrate. 展开更多
关键词 Nitric oxide reduction NH3 synthesis Fe_(3)c nanocrystal ELEcTROLYSIS Theoretical calculation
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泡沫Cu/AgCuTi复合中间层钎焊C/C与TC4接头组织及性能
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作者 王宁宁 朱海涛 +4 位作者 飞景明 安琪 宋延宇 刘多 宋晓国 《焊接学报》 北大核心 2025年第7期121-128,共8页
为解决C/C复合材料与TC4合金钎焊接头存在的残余应力集中及界面脆性相过量析出问题,文中采用泡沫Cu/AgCuTi复合中间层进行异质连接.系统研究了钎焊温度(860~920℃)对接头界面组织、抗剪强度和断口形貌的影响规律.结果表明,所有接头均形... 为解决C/C复合材料与TC4合金钎焊接头存在的残余应力集中及界面脆性相过量析出问题,文中采用泡沫Cu/AgCuTi复合中间层进行异质连接.系统研究了钎焊温度(860~920℃)对接头界面组织、抗剪强度和断口形貌的影响规律.结果表明,所有接头均形成可靠冶金结合,界面典型结构为TC4/Ti基固溶体+TiCu/Ag基固溶体+Cu基固溶体+TiCu_(2)/TiC/C/C复合材料.随着钎焊温度升高,钎缝宽度逐渐减小,但物相组成及分布规律保持一致.与传统AgCuTi钎料相比,泡沫Cu/AgCuTi复合中间层显著提高钎缝中Cu基固溶体含量,有效降低冷却过程中的残余应力积累并抑制脆性化合物生成.接头的抗剪强度随温度呈先增后减趋势,880℃时达到最大值29.2 MPa.断口分析显示,接头断裂特征与界面组织演化存在关联,表明复合中间层设计对提升接头性能具有积极作用. 展开更多
关键词 c/c复合材料 钎焊 泡沫cu 界面组织 力学性能
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Methanol oxidation in acidic and alkaline electrolytes using PtRuIn/C electrocatalysts prepared by borohydride reduction process 被引量:1
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作者 Santos M.C.L. Nandenha J. +2 位作者 Ayoub J.M.S. Assumpao M.H.M.T. Neto A.O. 《燃料化学学报》 EI CAS CSCD 北大核心 2018年第12期1462-1471,共10页
PtRuIn/C electrocatalysts( 20% metal loading by weight) were prepared by sodium borohydride reduction process using H_2PtCl6·6H_2O,RuCl_3·xH_2O and InCl_3·xH_2O as metal sources,borohydride as reducing ... PtRuIn/C electrocatalysts( 20% metal loading by weight) were prepared by sodium borohydride reduction process using H_2PtCl6·6H_2O,RuCl_3·xH_2O and InCl_3·xH_2O as metal sources,borohydride as reducing agent and Carbon Vulcan XC72 as support. The synthetized PtRuIn/C electrocatalysts were characterized by X-ray diffraction( XRD),energy dispersive analysis( EDX),transmission electron microscopy( TEM),cyclic voltammetry( CV),chronoamperommetry( CA) and polarization curves in alkaline and acidic electrolytes( single cell experiments). The XRD patterns showPtpeaks are attributed to the face-centered cubic( fcc) structure,and a shift of Pt( fcc) peaks indicates that Ru or In is incorporated into Ptlattice. TEMmicrographs showmetal nanoparticles with an average nanoparticle size between 2.7 and 3.5 nm. Methanol oxidation in acidic and alkaline electrolytes was investigated at room temperature,by CV and CA. PtRu/C( 50 ∶ 50) shows the highest activity among all electrocatalysts in study considering methanol oxidation for acidic and alkaline electrolyte. Polarization curves at 80 ℃ showPtRuIn/C( 50 ∶ 25 ∶ 25)with superior performance for methanol oxidation,when compared to Pt/C,PtIn/C and PtRu/C for both electrolytes. The best performance obtained by PtRuIn/C( 50 ∶ 25 ∶ 25) in real conditions could be associated with the increased kinetics reaction and/or with the occurrence simultaneously of the bifunctional mechanism and electronic effect resulting from the presence of Ptalloy. 展开更多
关键词 BOROHYDRIDE reduction process PtRuIn/c ELEcTROcATALYSTS METHANOL oxidation AcIDIc and ALKALINE electrolytes polarization cURVES
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大气CO_2浓度升高对水稻和稗草根系生长的影响 被引量:10
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作者 朱春梧 曾青 +4 位作者 朱建国 谢祖彬 黄文昭 陈改苹 陈春梅 《生态与农村环境学报》 CAS CSCD 北大核心 2006年第1期1-4,共4页
在两种N水平下(低N 10 mg.L-1和常N 30 mg.L-1),采用水培方法比较了分蘖盛期C3植物水稻(O ryzasativa)和C4植物稗草(Echinochloa crusgalli)在CO2浓度升高(550μmol.mol-1)和CO2浓度未升高(350μmol.mol-1)条件下的根系生长变化。结果表... 在两种N水平下(低N 10 mg.L-1和常N 30 mg.L-1),采用水培方法比较了分蘖盛期C3植物水稻(O ryzasativa)和C4植物稗草(Echinochloa crusgalli)在CO2浓度升高(550μmol.mol-1)和CO2浓度未升高(350μmol.mol-1)条件下的根系生长变化。结果表明,常N水平下高浓度CO2显著增加水稻和稗草的根干重、根体积、根总长和根直径,水稻对CO2浓度升高的响应强于稗草;低N胁迫时,高浓度CO2显著增加稗草的根干重、根体积和根总长,而对水稻生长无明显促进作用。在两种N水平下,高浓度CO2均显著降低水稻和稗草根系N含量,而C含量上升不明显,导致C/N比值显著增加。高浓度CO2显著降低水稻和稗草单位根重根毛数,这可能是CO2浓度升高条件下根系活力显著降低的形态学原因之一。 展开更多
关键词 FAcE(free-air carbon dioxide enrichment) c3植物 c4植物 水稻 稗草 根系 生长
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激光超声复合刻划C/SiC表面损伤特性研究
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作者 许金凯 黄筠瀚 +2 位作者 王佳琦 于占江 李英 《航空制造技术》 北大核心 2025年第19期14-23,共10页
碳纤维增强碳化硅基体复合材料(C/SiC)作为典型的陶瓷基复合材料(Ceramic matrix composite,CMC),具有高比强度、高比刚度、耐高温等优异性能,广泛应用于航空、航天、汽车等领域。为了探究不同能场作用下C/SiC复合材料表面的损伤形式,... 碳纤维增强碳化硅基体复合材料(C/SiC)作为典型的陶瓷基复合材料(Ceramic matrix composite,CMC),具有高比强度、高比刚度、耐高温等优异性能,广泛应用于航空、航天、汽车等领域。为了探究不同能场作用下C/SiC复合材料表面的损伤形式,本文分别对3个典型纤维方向进行了常规刻划(Conventional scratching,CS)、激光辅助刻划(Laser-assisted scratching,LAS)以及激光超声复合刻划(Laser-ultrasonic hybrid scratching,L-UHS),对比3种刻划方式下的刻划力、表面形貌等差异,分析激光超声复合能场对材料表面损伤影响。结果表明,相比于CS与LAS,L-UHS可有效降低刻划力,提高材料可加工性。L-UHS在不同方向上呈现出不同的断裂方式转变:在平行方向,纤维弯曲断裂失效减少,材料主要失效形式为层间断裂;在倾斜方向和垂直方向,纤维失效形式由弯曲断裂向剪切断裂转变。本文为C/SiC复合材料的激光超声复合加工提供理论指导。 展开更多
关键词 c/SIc复合材料 材料去除 表面损伤 激光超声复合刻划(Laser-ultrasonic hybrid scratching L-UHS)
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