期刊文献+
共找到12篇文章
< 1 >
每页显示 20 50 100
石墨烯导电剂片径对LiFePO_(4)正极中电荷传输的影响 被引量:7
1
作者 石杰 杨乐之 +1 位作者 李贺 栾紫林 《矿冶工程》 CAS CSCD 北大核心 2022年第5期137-142,共6页
为探究石墨烯导电剂片径对LiFePO_(4)电极中电荷传输的影响,通过纳米砂磨法制备了不同片径分布的石墨烯导电浆料,采用四探针、电化学阻抗谱测试对电极电子、离子传输电阻进行表征,发现随着石墨烯片径D_(50)增加,电极电子电阻呈反比例函... 为探究石墨烯导电剂片径对LiFePO_(4)电极中电荷传输的影响,通过纳米砂磨法制备了不同片径分布的石墨烯导电浆料,采用四探针、电化学阻抗谱测试对电极电子、离子传输电阻进行表征,发现随着石墨烯片径D_(50)增加,电极电子电阻呈反比例函数递减,电极离子电阻呈二次函数递增。当石墨烯片径D_(50)为10μm左右时,电极电子电阻与离子电阻之和为20.85Ω,接近最小总电阻,且电池具有较好的倍率性能,3C放电比容量达到121.1 mAh/g,容量保持率为76.92%。 展开更多
关键词 石墨 磷酸铁锂 导电剂 正极材料 石墨 电极电导率 电子电阻 离子电阻 倍率性能
下载PDF
催化裂化工艺技术的发展近况 被引量:24
2
作者 谢朝钢 钟孝湘 杨轶男 《石油炼制与化工》 CAS CSCD 北大核心 2001年第3期26-30,共5页
从多掺渣油、生产低碳烯烃、增加产品结构灵活性和新装置构型等方面系统地评述了国内外催化裂化工艺技术近年来的最新进展 ,指出增加掺渣比同时生产清洁燃料 。
关键词 催化裂化 烯径 渣油 汽油料 柴油 环境保护 述评
下载PDF
手性奎宁-卟啉锰催化剂的合成及其催化性能 被引量:2
3
作者 王亚军 刘彦钦 韩士田 《化学研究与应用》 CAS CSCD 北大核心 2003年第1期95-96,共2页
Six quinine-porphyrin Mn? complexes was synthesized by a certain of new chiral quinine-porphyrin.Their catalytic properties for the epoxidation of olefins in two-phase system (CH 2Cl 2/H 2O) were studies.The result in... Six quinine-porphyrin Mn? complexes was synthesized by a certain of new chiral quinine-porphyrin.Their catalytic properties for the epoxidation of olefins in two-phase system (CH 2Cl 2/H 2O) were studies.The result indicated these not only can enhance catalyzing activity,but also showed obvious phase-transfer function.That the reaction condition had affacfed the results of epoxidation. 展开更多
关键词 奎宁-卟啉锰 催化剂 烯径环氧化 相转移催化
下载PDF
Numerical simulation of diffusion process for oxidative dehydrogenation of butene to butadiene
4
作者 黄凯 林生 周建成 《Journal of Southeast University(English Edition)》 EI CAS 2015年第4期572-576,共5页
A comprehensive single particle model which includes the mesoscale and microscale models was developed to study the influence of particle diameter on mass and heat transfer occurring within a ferrite catalyst during t... A comprehensive single particle model which includes the mesoscale and microscale models was developed to study the influence of particle diameter on mass and heat transfer occurring within a ferrite catalyst during the oxidative dehydrogenation of butene to butadiene process. The verified model can be used to investigate the influence of catalyst diameter on the flow distribution inside the particle. The simulation results demonstrate that the mass fraction gradients of all species, temperature gradient and pressure gradient increase with the increase of the particle diameter. It means that there is a high intraparticle transfer resistance and strong diffusion when applying the large catalysts. The external particle mass transfer resistance is nearly constant under different particle diameters so that the effect of particle diameter at external diffusion can be ignored. A large particle diameter can lead to a high surface temperature, which indicates the external heat transfer resistance. Moreover, the selectivity of reaction may be changed with a variety of particle diameters so that choosing appropriate particle size can enhance the production of butadiene and optimize the reaction process. 展开更多
关键词 multi-scale model mass and heat transfer particle diameter oxidative dehydrogenation of butene to butadiene single particle model transfer resistance
下载PDF
Theoretical Study of Reaction Paths and Transition States on Conversion Methane into C_2 Hydrocarbons Through Plasma 被引量:2
5
作者 王保伟 杨恩翠 +1 位作者 许根慧 郝金库 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2007年第1期44-50,共7页
The direct synthesis of C2 hydrocarbons (ethylene, acetylene and ethane) from methane is one of the most important task in C1 chemistry. Higher conversion of methane and selectivity to C2 hydrocarbons can be real-iz... The direct synthesis of C2 hydrocarbons (ethylene, acetylene and ethane) from methane is one of the most important task in C1 chemistry. Higher conversion of methane and selectivity to C2 hydrocarbons can be real-ized through plasma reaction. In order to explore the reaction process and mechanism, the possible reaction paths (1)—(4) were proposed on coupling reaction of methane through plasma and studied theoretically using semi-PM3 method [PM3 is parameterization method of modified neglect of diatomic overlap (MNDO)] including determining the transition state, calculating the activation energy and thermodynamic state functions and analyzing the bond or-der and intrinsic reaction coordinate. The reaction heat results indicate that the reactions (2) and (4) are exothermic, while reactions of (1) and (3) are endothermic. The activation energy results show that activation energy for reac-tions (1) and (2) was much lower than that of reaction paths (3) and (4). Therefore, paths (1) and (2) is the favorable reaction path energetically. More interestingly by comparing the intrinsic reaction coordinated (IRC) of the reaction paths (1) and (2), it is found that the variations of bond lengths in reaction path (1) has a crucial effect on the poten-tial energy, while in reaction path (2), the adjustment of the system geometry also contributes to the whole potential energy of the system. 展开更多
关键词 reaction path transition state METHANE PLASMA PM3
下载PDF
Link-Vertex Topology Aggregation for Multi-domain Path Computation with Hierarchical PCE Architecture 被引量:1
6
作者 Peng Yunfeng Chen Zhen +2 位作者 Zhao Changming Wang Zongwei Long Keping 《China Communications》 SCIE CSCD 2012年第1期86-91,共6页
Inter-domain path computing is one big issue in multi-domain networks. The Hierarchical Path Computing Element (H-PCE) is a semi-central architecture for computing inter-domain path. To facilitate H-PCE in inter-domai... Inter-domain path computing is one big issue in multi-domain networks. The Hierarchical Path Computing Element (H-PCE) is a semi-central architecture for computing inter-domain path. To facilitate H-PCE in inter-domain path computing, this paper proposed a topology aggregation scheme to abstract the edge nodes and their connected inter-domain link as one vertex to achieve more optimal paths and confidentiality guarantee. The effectiveness of the scheme has been demonstrated on solving wavelength routing in multi-domain Wavelength Division Multiplexing (WDM) network via simulation. Simulation results show that this scheme reduces at least 10% inter-domain blocking probability, compared with the traditional Domain-to-the-Node (DtN) scheme. 展开更多
关键词 ROUTING PCE link-vertex aggregation inter-domain path computation multi-domain network topology aggregation
下载PDF
Construction and characterization of a normalized cDNA library of Nannochloropsis oculata(Eustigmatophyceae) 被引量:2
7
作者 俞建中 马晓磊 +2 位作者 潘克厚 杨官品 于文功 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2010年第4期802-807,共6页
We constructed and characterized a normalized cDNA library of Nannochloropsis oculata CS-179,and obtained 905 nonredundant sequences(NRSs) ranging from 431-1 756 bp in length.Among them,496 were very similar to nonred... We constructed and characterized a normalized cDNA library of Nannochloropsis oculata CS-179,and obtained 905 nonredundant sequences(NRSs) ranging from 431-1 756 bp in length.Among them,496 were very similar to nonredundant ones in the GenBank(E ≤1.0e-05),and 349 ESTs had significant hits with the clusters of eukaryotic orthologous groups(KOG).Bases G and/or C at the third position of codons of 14 amino acid residues suggested a strong bias in the conserved domain of 362 NRSs(>60%).We also identified the unigenes encoding phosphorus and nitrogen transporters,suggesting that N.oculata could efficiently transport and metabolize phosphorus and nitrogen,and recognized the unigenes that involved in biosynthesis and storage of both fatty acids and polyunsaturated fatty acids(PUFAs),which will facilitate the demonstration of eicosapentaenoic acid(EPA) biosynthesis pathway of N.oculata.In comparison with the original cDNA library,the normalized library significantly increased the efficiencies of random sequencing and rarely expressed genes discovering,and decreased the frequency of abundant gene sequences. 展开更多
关键词 EUSTIGMATOPHYCEAE Nannochloropsis oculata normalized cDNA library expressed sequence tag
下载PDF
Analysis of Potential Energy Surface for Butanone Isomerization 被引量:3
8
作者 Xue Yang Bing Yan +3 位作者 Hai-feng Xu Rui-han Zhu Mei-xia Zhang Da-jun Ding 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2013年第5期519-525,I0003,共8页
The potential energy surfaces for butanone isomerization have been investigated by density function theory calculation. Six main reaction pathways are confirmed using the intrinsic reaction coordinate method, and the ... The potential energy surfaces for butanone isomerization have been investigated by density function theory calculation. Six main reaction pathways are confirmed using the intrinsic reaction coordinate method, and the corresponding isomerization products are 1-buten-2-ol, 2-buten-2-ol, butanal or 1-buten-l-ol, methyl 1-propenyl ether, methyl allyl ether, and ethyl vinyl ether, respectively. Among them, there are three pathways through butylene oxide, indicating butylene oxide is an important intermediate product during butanone isomer ization. The calculated vertical ionization energies of the reactant and its products are in a good agreement with the experimental values available. From the consideration for the relative energies Of transition states and the number of high-energy barriers we infer that the reaction pathway butanone-*l-buten-2-ol---2-buten-2-oi is the most competitive. The obtained results are informative for future studies on isomerization of ketone molecules. 展开更多
关键词 BUTANONE ISOMERIZATION Density function theory Potential energy surface Vertical ionization energy
下载PDF
聚乳酸-症基乙酸共聚物/氧化石墨烯纳米纺丝膜搭载脑源性神经营养因子对脊髓损伤的修复作用 被引量:3
9
作者 潘肃 齐治平 +6 位作者 郑爽 马悦 付川 孔维健 余双奇 杨小玉 张卓 《中华创伤杂志》 CAS CSCD 北大核心 2019年第7期597-604,共8页
目的探讨搭载有脑源性神经营养因子(BDNF)的聚乳酸-轻基乙酸共聚物(PLGA)/氧化石墨烯(GO)纳米纺丝纤维膜对神经干细胞(NSCs)增殖分化的影响及其对脊髓损伤的修复作用。方法制备PLGA/G0纳米纺丝膜并物理吸附BDNF,采用扫描电镜观察PLGA/G... 目的探讨搭载有脑源性神经营养因子(BDNF)的聚乳酸-轻基乙酸共聚物(PLGA)/氧化石墨烯(GO)纳米纺丝纤维膜对神经干细胞(NSCs)增殖分化的影响及其对脊髓损伤的修复作用。方法制备PLGA/G0纳米纺丝膜并物理吸附BDNF,采用扫描电镜观察PLGA/GO纺丝膜的微观结构。采用ELISA测定BDNF在PLGA/GO纺丝膜上的搭载效率和释放曲线。将NSCs接种在PLGA/GO和PLGA/GO/BDNF材料表面,釆用MTT法对各组的吸光度值进行测定,利用免疫荧光和PCR对33微管蛋白(Tuj-1)表达进行观察。随后将30只雌性SD大鼠按随机数字表法分为损伤对照组(10只)、PLGA/GO组(10只)和PLGA/GO/BDNF组(10只),利用维纳斯剪切割T,脊髓组织建立脊髓半切损伤动物模型,PLGA/GO组和PLGA/GO/BDNF组分别将对应的纳米纺丝膜原位移植覆盖于损伤处。造模后1,7,14和28d利用BBB评分对大鼠的运动功能进行评价。于伤后1个月时取材,免疫荧光染色观察神经元特异性核蛋白(NeuN)和胶质纤维酸性蛋白(GFAP)的表达情况。结果扫描电镜结果显示,PLGA/GO纺丝膜为不规则的光滑纤维样结构,纤维直径(987.5±176.3)nm,NSCs可以在纺丝膜上正常分化为神经元。ELISA结果显示,PLGA/GO纺丝膜对BDNF的负载率约为47.5%;释放曲线显示,BDNF在第1天首先释放30%左右,随后至第21天释放至60%左右。MTT和PCR结果显示,PLGA/GO/BDNF组的吸光度(A)值和Tuj-1表达显著高于PLGA/G0组(P<0.05)。造模后28d,PLGA/GO/BDNF组BBB评分为(15.3±0.7)分,显著高于损伤对照组的(11.8±0.8)分和PLGA/GO组的(12.7±0.8)分(P<0.05)。免疫荧光结果显示,PLGA/GO/BDNF组NeuN表达为(13.7±2.2)个,显著高于损伤对照组的(4.3±2.9)个(P<0.05);PLGA/GO/BDNF组GFAP表达为(25.6±4.3)%,显著低于损伤对照组的(38.5±6.2)%和PLGA/GO组的(36.7±7.3)%(P<0.05)。结论搭载有BDNF的PLGA/GO纳米纺丝纤维膜可以在体外有效促进NSCs增殖和神经元向分化,并通过体内损伤处原位移植有效修复脊髓损伤。 展开更多
关键词 脊髓损伤 神经干细胞 脑源性神经营养因子 聚乳酸-基乙酸共聚物/氧化石墨
原文传递
Re-examining Photodetachment of H^- near a Spherical Surface using Closed-Orbit Theory
10
作者 尤晓鹏 杜孟利 《Communications in Theoretical Physics》 SCIE CAS CSCD 2016年第3期354-360,共7页
Photodeachment of H^-near a reflective spherical surface was studied by Haneef et al.[J.Phys.B:At.Mol.Opt.Phys.44(2011)195004]using a theoretical imaging method.The total cross section displays interesting oscillation... Photodeachment of H^-near a reflective spherical surface was studied by Haneef et al.[J.Phys.B:At.Mol.Opt.Phys.44(2011)195004]using a theoretical imaging method.The total cross section displays interesting oscillations.Here we re-examine the total photodetachment cross section of this system by directly applying the standard closed-orbit theory.Our result for the total cross section differs from the result obtained by Haneef et al.The difference between the two results vanishes in the limit of large radius of the reflective sphere.We argue that the theoretical imaging method developed originally for photodetachment near a Hat surface can not be directly applied to the present system. 展开更多
关键词 PHOTODETACHMENT hydrogen negative ion
原文传递
VdPKS1 is required for melanin formation and virulence in a cotton wilt pathogen Verticillium dahliae 被引量:16
11
作者 Ting Zhang Bosen Zhang +6 位作者 Chenlei Hua Pei Meng Sheng Wang Zhirong Chen Yejuan Du Feng Gao Jiafeng Huang 《Science China(Life Sciences)》 SCIE CAS CSCD 2017年第8期868-879,共12页
Verticillium dahliae is a soil-borne phytopathogenic fungus that causes vascular wilt disease in a broad range of hosts. This pathogen survives for many years in soil in the form ofmelanized microsclerotia. To investi... Verticillium dahliae is a soil-borne phytopathogenic fungus that causes vascular wilt disease in a broad range of hosts. This pathogen survives for many years in soil in the form ofmelanized microsclerotia. To investigate the melanin synthesis in V.. dahliae, we identified a polyketide synthase gene in V. dahliae, namely VdPKS1. PKS1 is known to involve in the dihydroxynaphthalene melanin synthesis pathway in many fungi. We found that VdPKS1 was required for melanin formation but not for microsclerotial production in E dahliae. The VdPKS1 gene-disruption mutant (vdpksl) formed melanin-deficient albino microsclerotia, which did not affect the fungal colonization in host tissues but significantly reduced the disease severity. Gene transcription analysis in the wild-type and the vdpks1 strains suggested that VdPKS1 gene-disruption influenced the expression of a series of genes involved in ethylene biosynthesis, microsclerotial formation and pathogenesis. Our results suggest that the VdPKS1-mediated melanin synthesis is important for virulence and developmental traits of E dahliae. 展开更多
关键词 Verticillium dahliae VdPKS1 MELANIN VIRULENCE CONIDIATION MICROSCLEROTIA
原文传递
Effect of Polyacrylamide Application on Runoff,Erosion,and Soil Nutrient Loss Under Simulated Rainfall 被引量:14
12
作者 WANG Ai-Ping LI Fa-Hu YANG Sheng-Min 《Pedosphere》 SCIE CAS CSCD 2011年第5期628-638,共11页
Soil erosion affects soil productivity and environmental quality.A laboratory research experiment under simulated heavy rainfall with tap water was conducted to investigate the effects of anionic polyacrylamide(PAM) a... Soil erosion affects soil productivity and environmental quality.A laboratory research experiment under simulated heavy rainfall with tap water was conducted to investigate the effects of anionic polyacrylamide(PAM) application rates(0,0.5,1.0,and 2.0 g m-2) and molecular weights(12 and 18 Mg mol-1) on runoff,soil erosion,and soil nutrient loss at a slope of 5°.The results showed the two lower rates of PAM application decreased runoff while the highest rate increased runoff as compared with the control.Sediment concentration and soil mass loss increased significantly with the increasing PAM application rate.Compared with the control,PAM application decreased K+,NH4+,and NO3-concentrations in sediment and K+ and NH+4 concentrations in runoff,but significantly increased the mass losses of K+,NH4+,and NO-3 over soil surface except for the NH4+ at PAM application rate lower than 1.0 g m-2.PAM application decreased the proportion of K+ loss with runoff to its total mass loss over soil surface from 60.1% to 16.4%.However,it did not affect the NH4+ and NO3-losses with runoff,and more than 86% of them were lost with runoff.A higher PAM molecular weight resulted in less soil erosion and K+ mass loss but had little effect on runoff and NH+4 and NO3-losses.PAM application did not prevent soil erosion and the mass losses of K+ and NO3-under experimental conditions. 展开更多
关键词 application rate mass loss molecular weight nutrient concentration sediment concentration
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部