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Understanding Bridging Sites and Accelerating Quantum Efficiency for Photocatalytic CO_(2) Reduction
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作者 Kangwang Wang Zhuofeng Hu +8 位作者 Peifeng Yu Alina M.Balu Kuan Li Longfu Li Lingyong Zeng Chao Zhang Rafael Luque Kai Yan Huixia Luo 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第1期68-84,共17页
We report a novel double-shelled nanoboxes photocatalyst architecture with tailored interfaces that accelerate quantum efficiency for photocatalytic CO_(2) reduction reaction(CO_(2)RR)via Mo–S bridging bonds sites in... We report a novel double-shelled nanoboxes photocatalyst architecture with tailored interfaces that accelerate quantum efficiency for photocatalytic CO_(2) reduction reaction(CO_(2)RR)via Mo–S bridging bonds sites in S_(v)–In_(2)S_(3)@2H–MoTe_(2).The X-ray absorption near-edge structure shows that the formation of S_(v)–In_(2)S_(3)@2H–MoTe_(2) adjusts the coordination environment via interface engineering and forms Mo–S polarized sites at the interface.The interfacial dynamics and catalytic behavior are clearly revealed by ultrafast femtosecond transient absorption,time-resolved,and in situ diffuse reflectance–Infrared Fourier transform spectroscopy.A tunable electronic structure through steric interaction of Mo–S bridging bonds induces a 1.7-fold enhancement in S_(v)–In_(2)S_(3)@2H–MoTe_(2)(5)photogenerated carrier concentration relative to pristine S_(v)–In_(2)S_(3).Benefiting from lower carrier transport activation energy,an internal quantum efficiency of 94.01%at 380 nm was used for photocatalytic CO_(2)RR.This study proposes a new strategy to design photocatalyst through bridging sites to adjust the selectivity of photocatalytic CO_(2)RR. 展开更多
关键词 Quantum efficiency Electronic structure Steric interaction Bridging sites CO_(2)reduction
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Fe-N_(x) sites coupled with core-shell FeS@C nanoparticles to boost the oxygen catalysis for rechargeable Zn-air batteries
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作者 Katam Srinivas Zhuo Chen +3 位作者 Anran Chen Fei Ma Ming-qiang Zhu Yuanfu Chen 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第3期565-577,I0013,共14页
The development of efficient single-atom catalysts(SACs) for the oxygen reduction reaction(ORR)remains a formidable challenge,primarily due to the symmetric charge distribution of metal singleatom sites(M-N_(4)).To ad... The development of efficient single-atom catalysts(SACs) for the oxygen reduction reaction(ORR)remains a formidable challenge,primarily due to the symmetric charge distribution of metal singleatom sites(M-N_(4)).To address such issue,herein,Fe-N_(x) sites coupled synergistic catalysts fabrication strategy is presented to break the uniform electronic distribution,thus enhancing the intrinsic catalytic activity.Precisely,atomically dispersed Fe-N_(x) sites supported on N/S-doped mesoporous carbon(NSC)coupled with FeS@C core-shell nanoparticles(FAS-NSC@950) is synthesized by a facile hydrothermal reaction and subsequent pyrolysis.Due to the presence of an in situ-grown conductive graphitic layer(shell),the FeS nanoparticles(core) effectively adjust the electronic structure of single-atom Fe sites and facilitate the ORR kinetics via short/long-range coupling interactions.Consequently,FAS-NSC@950displays a more positive half-wave potential(E_(1/2)) of 0.871 V with a significantly boosted ORR kinetics(Tafel slope=52.2 mV dec^(-1)),outpacing the commercial Pt/C(E_(1/2)=0.84 V and Tafel slope=54.6 mV dec^(-1)).As a bifunctional electrocatalyst,it displays a smaller bifunctional activity parameter(ΔE) of 0.673 V,surpassing the Pt/C-RuO_(2) combination(ΔE=0.724 V).Besides,the FAS-NSC@950-based zincair battery(ZAB) displays superior power density,specific capacity,and long-term cycling performance to the Pt/C-Ir/C-based ZAB.This work significantly contributes to the field by offering a promising strategy to enhance the catalytic activity of SACs for ORR,with potential implications for energy conversion and storage technologies. 展开更多
关键词 Fe-N_(x)sites Core-shell FeS@C Synergistic interactions Oxygen reduction reaction Zn-air battery
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Cancer Specific Non-Synonymous Single Nucleotide Polymorphism Prediction in the Context of Haplotype and Protein Interacting Sites
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作者 Pakeeza Akram Li Liao 《Journal of Biomedical Science and Engineering》 2017年第5期28-44,共17页
In this work, we study predicting the effect of non-synonymous SNPs on several cancers. We trained classifiers on both sequential and structural features extracted from the affected genes and assessed the predictions ... In this work, we study predicting the effect of non-synonymous SNPs on several cancers. We trained classifiers on both sequential and structural features extracted from the affected genes and assessed the predictions made by the trained classifiers using cross validation. Specifically, we investigated how the prediction performance can be improved by connecting SNPs in the context of haplotype and interacting sites of proteins encoded by affected genes. We found that accuracy was consistently enhanced by combining sequential and structural features, with increase ranging from a few percentage points up to more than 20 percentage points. The results for putting SNPs in the context of interacting sites were less consistent. Compared to individual SNPs, these that appear together in haplotype showed stronger correlation with one another and with the phenotype, and therefore led to significant improvement inprediction performance, with ROC score increased from 0.81 to 0.95. Although some similar effect has been expected for connecting SNPs to interacting sites in proteins, the performance actually got worse. This decrease in prediction accuracy may be caused by the small data set being used in the study, as many affected proteins in the study do not have known interacting sites. 展开更多
关键词 Single NUCLEOTIDE Polymorphism HAPLOTYPE interaction siteS PREDICTION CANCER
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Activity patterns and resource partitioning: seven species at watering sites in the Altun Mountains, China 被引量:4
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作者 XUE Yadong LI Jia +3 位作者 SAGEN Guli ZHANG Yu DAI Yunchuan LI Diqiang 《Journal of Arid Land》 SCIE CSCD 2018年第6期959-967,共9页
As part of a larger project to examine the richness and distribution of wildlife in Kumtag Desert area, we conducted camera trapping surveys during the period 2010–2012 at seven watering sites in an arid region of th... As part of a larger project to examine the richness and distribution of wildlife in Kumtag Desert area, we conducted camera trapping surveys during the period 2010–2012 at seven watering sites in an arid region of the Altun Mountains in western China. Information on activity patterns of the wild bactrian camel (Camelus ferus), kiang (Equus kiang), goitered gazelle (Gazella subgutturosa), argali (Ovis ammon), blue sheep (Pseudois nayaur), red fox (Vulpes vulpes), and wolf (Canis lupus) was obtained. We found that the wild camel, kiang, goitered gazelle, argali, and blue sheep were predominantly diurnal at watering sites, whereas red fox and wolf were nocturnal. Five herbivores partitioned the use of watering sites in a temporal manner to minimize the risk of predation by carnivores. The wild camel was the dominant herbivorous species at the watering sites. The kiang, goitered gazelle, argali, and blue sheep displayed adaptive water use by altering spatial or temporal patterns based on the presence or absence of wild camel, to minimize the risk of interspecific strife. These results are suggestive of the differences in activity patterns that might modulate water partitioning by different species, and provide insights for the development of conservation strategies for integrated species and decisions regarding water development in the Altun Mountains. 展开更多
关键词 camera trapping competition desert animal interaction watering site niche partitioning
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Influence of Functional Groups and Modification Sites of Metal-Organic Frameworks on CO2/CH4 Separation:A Monte Carlo Simulation Study
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作者 龚捷 李炜 李松 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2018年第1期52-60,I0001,共10页
In order to explore the influence of modification sites of functional groups on landfill gas (CO2/CH4) separation performance of metal-organic frameworks (MOFs), six types of or- ganic linkers and three types of f... In order to explore the influence of modification sites of functional groups on landfill gas (CO2/CH4) separation performance of metal-organic frameworks (MOFs), six types of or- ganic linkers and three types of functional groups (i.e. -F, -NH2, -CH3) were used to construct 36 MOFs of pcu topology based on copper paddlewheel. Grand canonical Monte Carlo sim- ulations were performed in this work to evaluate the separation performance of MOFs at low (vacuum swing adsorption) and high (pressure swing adsorption) pressures, respectively. Simulation results demonstrated that CO2 working capacity of the unfunctionalized MOFs generally exhibits pore-size dependence at 1 bar, which increases with the decrease in pore sizes. It was also found that -NH2 funetionalized MOFs exhibit the highest CO2 uptake due to the enhanced Coulombic interactions between the polar -NH2 groups and the quadrupole moment of CO2 molecules, which is followed by -CH3 and -F functionalized ones. Moreover, positioning the functional groups -NH2 and -CH3 at sites far from the metal node (site b) exhibits more significant enhancement on CO2/CH4 separation performance compared to that adjacent to the metal node (site a). 展开更多
关键词 Metal-organic frmneworks Pore-size dependence Functional groups Modifi-cation sites interaction energy
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Time-dependent Diffusion Coefficient and Conventional Diffusion Constant of Nanoparticles in Polymer Melts by Mode-coupling Theory
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作者 赖鑫昱 赵南蓉 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2013年第2期163-171,I0003,共10页
Time-dependent diffusion coefficient and conventional diffusion constant are calculated and analyzed to study diffusion of nanoparticles in polymer melts. A generalized Langevin equa- tion is adopted to describe the d... Time-dependent diffusion coefficient and conventional diffusion constant are calculated and analyzed to study diffusion of nanoparticles in polymer melts. A generalized Langevin equa- tion is adopted to describe the diffusion dynamics. Mode-coupling theory is employed to calculate the memory kernel of friction. For simplicity, only microscopic terms arising from binary collision and coupling to the solvent density fluctuation are included in the formalism. The equilibrium structural information functions of the polymer nanocomposites required by mode-coupling theory are calculated on the basis of polymer reference interaction site model with Percus-Yevick closure. The effect of nanoparticle size and that of the polymer size are clarified explicitly. The structural functions, the friction kernel, as well as the diffusion coefficient show a rich variety with varying nanoparticle radius and polymer chain length. We find that for small nanoparticles or short chain polymers, the characteristic short time non-Markov diffusion dynamics becomes more prominent, and the diffusion coefficient takes longer time to approach asymptotically the conventional diffusion constant. This constant due to the microscopic contributions will decrease with the increase of nanoparticle size, while increase with polymer size. Furthermore, our result of diffusion constant from mode- coupling theory is compared with the value predicted from the Stokes-Einstein relation. It shows that the microscopic contributions to the diffusion constant are dominant for small nanoparticles or long chain polymers. Inversely, when nanonparticle is big, or polymer chain is short, the hydrodynamic contribution might play a significant role. 展开更多
关键词 Time-dependent diffusion coefficient Conventional diffusion coefficient Poly-mer melts Mode-coupling theory Polymer reference interaction site model
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Variation among poplar clones for growth and crown traits under field conditions at two sites of North-western India 被引量:5
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作者 G.P.S. Dhillon Avtar Singh +1 位作者 D.S. Sidhu H.S. Brar 《Journal of Forestry Research》 SCIE CAS CSCD 2013年第1期61-67,共7页
We evaluated the growth and crown traits of 36 poplar clones at two distinct agro-climatic regions of Punjab (Ludhiana and Bathinda) in northwestern India, following randomized block design with three replications a... We evaluated the growth and crown traits of 36 poplar clones at two distinct agro-climatic regions of Punjab (Ludhiana and Bathinda) in northwestern India, following randomized block design with three replications and plot size of four trees. Significant differences among clones (p〈0.001) were observed for diameter at breast height (DBH), tree height, volume, crown width and number of branches under both the site conditions. Clones ‘G-3’, ‘25-N’ and ‘41-N’ at Ludhiana and ‘G-3’, ‘RD-01’ and ‘S7C8’ at Bathinda were found to be superior for volume production. All growth and crown traits registered significantly higher values at Ludhiana in comparison to those at Bathinda. Clone site interaction was also significant (p〈0.001). For volume, clones ‘L-62/84’, ‘113520’, ‘25-N’ and ‘S4C2’ witnessed huge fluctuations in ranking between sites. The correlations between growth traits were positive and highly significant (p〈0.001) at both sites. The clonal mean heritability was moderate for DBH and volume both at Ludhiana (0.61–0.66) and Bathinda (0.61–0.62). Across sites, the genetic advance was the highest for volume (49.76%) and the lowest (6.50%) in case of height. 展开更多
关键词 clonal heritability clonal selection clone-site interaction genetic correlation Populus deltoides
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Prediction of Interaction Sites of PcRab7-VP28
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作者 Xiaofeng Ji Yuan Zheng Jun Sheng 《Computational Molecular Bioscience》 2021年第2期50-56,共7页
White spot syndrome virus (WSSV) is one of the most important pathogens in the world. Since its outbreak in 1993, the virus has caused huge economic losses. Studies have confirmed that in the early stage of infection,... White spot syndrome virus (WSSV) is one of the most important pathogens in the world. Since its outbreak in 1993, the virus has caused huge economic losses. Studies have confirmed that in the early stage of infection, VP28, the main envelope protein of WSSV, as a viral adhesion protein, binds to PcRab7 of <em>Penaeus chinensis</em> to help the virus enter the host cells. Understanding the mechanism of PcRab7-VP28 interaction is of great significance to understand the mechanism of WSSV infection and the development of antiviral drugs. In this research, the interaction interface and interaction sites were predicted by using the methods of molecular simulations. Results showed that VP28 binds to the second <em>β</em>-sheet (L73-D86) of PcRab7, which is consistent with the region detected in previous studies. Furthermore, we speculated the possible interaction sites in PcRab7 are E81, F77 and D76. These results may contribute to a deep understanding of the infection mechanism of WSSV on the host. 展开更多
关键词 White Spot Syndrome Virus (WSSV) interaction sites PENAEUS
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Overview of the seismic input at dam sites in China
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作者 Houqun Chen 《Earthquake Science》 2022年第5期410-425,共16页
The current Chinese national standard,the Standard for Seismic Design of Hydraulic Structures(GB51247),released in 2018,is strictly based on China’s national conditions and dam engineering features.A comprehensive an... The current Chinese national standard,the Standard for Seismic Design of Hydraulic Structures(GB51247),released in 2018,is strictly based on China’s national conditions and dam engineering features.A comprehensive and systematic overview of the basis of the seismic fortification requirements,the framework of the fortification criteria,and the mechanisms of seismic input related to the seismic design of dams are presented herein.We first analyzed and clarified several conceptual aspects in traditional seismic design of dams.Then,for the seismic input at the dam site described in the first national standard for hydraulic structures,we expounded innovative concepts,ideas,and methods to make relevant provisions more realistic and practical and discussed whether reservoir earthquakes must be included in the seismic fortification framework of dams.This study seeks to incorporate seismic input at the dam site into traditional seismic design practice to promote its improvement from the quasi-static method to the dynamic method and from the closed vibration system to an open wave propagation system,to ensure that the seismic design of dams becomes more reasonable,reliable,scientific,and economic. 展开更多
关键词 seismic resistance of dams seismic input at the dam site dynamic dam-foundation interaction closed vibration system open wave propagation system
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Incorporating the Built Environment Interactions into Spatial Pattern Models to Understand Urban Metabolism in Tokyo's Residential Area
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作者 Akiko Kokubun Eiji Hato 《Journal of Civil Engineering and Architecture》 2013年第7期854-866,共13页
In Tokyo, as residential areas exist in the urban areas and are composed of areas owned by individual land owners, basically spatial changes are brought by redevelopments of each sites conducted by individual circumst... In Tokyo, as residential areas exist in the urban areas and are composed of areas owned by individual land owners, basically spatial changes are brought by redevelopments of each sites conducted by individual circumstances and motivations. Continuous redevelopments and spatial changes can be found dispersedly in areas. Once the spatial change in a certain site occurred in an area as a building, it will be contained in the built environment of the residential area which is defined by residents, planners and designers who will take part in the following spatial changes. In Tokyo, public transportation facilities are well developed, and residents' daily life involves activities such as a slow walking and bicycle, etc. around the place of residence near the public transportation hubs, each living territories are formed in this kind of manner. Considering the maintenance of spatial value in residential areas while understanding transformation of visual local environment in residential areas which focuses on appearance of each spatial change in an area of street will be of significant importance. In this paper, the authors try to describe interactions of spatial changes in existing urban residential areas focusing on utility of players who might take part in the following spatial changes and the method of discrete choice model. 展开更多
关键词 Existing urban residential areas in Tokyo redevelopment of housing site modification interaction discrete choicemodel.
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Divalent cation tolerance protein binds to β-secretase and inhibits the processing of amyloid precursor protein 被引量:1
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作者 Runzhong Liu Haibo Hou +2 位作者 Xuelian Yi Shanwen Wu Huan Zeng 《Neural Regeneration Research》 SCIE CAS CSCD 2013年第11期991-999,共9页
The deposition of amyloid-beta is a pathological hallmark of Alzheimer's disease, Amyloid-beta is derived from amyloid precursor protein through sequential proteolytic cleavages by β-secretase (beta-site amyloid pr... The deposition of amyloid-beta is a pathological hallmark of Alzheimer's disease, Amyloid-beta is derived from amyloid precursor protein through sequential proteolytic cleavages by β-secretase (beta-site amyloid precursor protein-cleaving enzyme 1) and r-secretase. To further elucidate the roles of beta-site amyloid precursor protein-cleaving enzyme 1 in the development of AIzheimer's disease, a yeast two-hybrid system was used to screen a human embryonic brain cDNA library for proteins directly interacting with the intracellular domain of beta-site amyloid precursor protein-cleaving enzyme 1. A potential beta-site amyloid precursor protein-cleaving enzyme 1- interacting protein identified from the positive clones was divalent cation tolerance protein. Immunoprecipitation studies in the neuroblastoma cell line N2a showed that exogenous divalent cation tolerance protein interacts with endogenous beta-site amyloid precursor protein-cleaving enzyme 1. The overexpression of divalent cation tolerance protein did not affect beta-site amyloid precursor protein-cleaving enzyme 1 protein levels, but led to increased amyloid precursor protein levels in N2a/APP695 cells, with a concomitant reduction in the processing product amyloid precursor protein C-terminal fragment, indicating that divalent cation tolerance protein inhibits the processing of amyloid precursor protein. Our experimental findings suggest that divalent cation tolerance protein negatively regulates the function of beta-site amyloid precursor protein-cleaving enzyme 1. Thus, divalent cation tolerance protein could play a protective role in Alzheimer's disease. 展开更多
关键词 neural regeneration brain injury neurodegenerative diseases Alzheimer's disease amyloid-betaβ-secretase amyloid precursor protein beta-site amyloid precursor protein-cleaving enzyme 1 interaction amyloid precursor protein C-terminal fragment western blot yeast two-hybridization grants-supported paper NEUROREGENERATION
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Dynamic soil-tunnel interaction in layered half-space for incident P-and SV-waves 被引量:4
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作者 Jia Fu Jianwen Liang Lin Qin 《Earthquake Science》 CSCD 2015年第4期275-284,共10页
The dynamic soil-tunnel interaction is studied by the model of a rigid tunnel embedded in layered half-space, which is simplified as a single soil layer on elastic bedrock to the excitation of P- and SV-waves. The ind... The dynamic soil-tunnel interaction is studied by the model of a rigid tunnel embedded in layered half-space, which is simplified as a single soil layer on elastic bedrock to the excitation of P- and SV-waves. The indirect boundary element method is used, combined with the Green' s function of distributed loads acting on inclined lines. It is shown that the dynamic characteristics of soil-tunnel interaction in layered half-space are different much from that in homoge- neous half-space, and that the mechanism of soil-tunnel interaction is also different much from that of soil-founda- tion-superstructure interaction. For oblique incidence, the tunnel response for in-plane incident SV-waves is com- pletely different from that for incident SH-waves, while the tunnel response for vertically incident SV-wave is very similar to that of vertically incident SH-wave. 展开更多
关键词 Underground tunnel Layered half-space P-wave and SV-wave Indirect boundary element method Soil-tunnel interaction ~ site dynamic characteristics
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Atom-level interfacial synergy of single-atom site catalysts for electrocatalysis 被引量:5
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作者 Yao Wang Dingsheng Wang Yadong Li 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第2期103-115,共13页
Single-atom site catalysts(SACs)have made great achievements due to their nearly 100%atomic utilization and uniform active sites.Regulating the surrounding environment of active sites,including electron structure and ... Single-atom site catalysts(SACs)have made great achievements due to their nearly 100%atomic utilization and uniform active sites.Regulating the surrounding environment of active sites,including electron structure and coordination environment via atom-level interface regulation,to design and construct an advanced SACs is of great significance for boosting electrocatalytic reactions.In this review,we systemically summarized the fundamental understandings and intrinsic mechanisms of SACs for electrocatalytic applications based on the interface site regulations.We elaborated the several different regulation strategies of SACs to demonstrate their ascendancy in electrocatalytic applications.Firstly,the interfacial electronic interaction was presented to reveal the electron transfer behavior of active sites.Secondly,the different coordination structures of metal active center coordinated with two or three non-metal elements were also summarized.In addition,other atom-level interfaces of SACs,including metal atom–atom interface,metal atom-X-atom interface(X:non-metal element),metal atom-particle interface,were highlighted and the corresponding promoting effect towards electrocatalysis was disclosed.Finally,we outlooked the limitations,perspectives and challenges of SACs based on atomic interface regulation. 展开更多
关键词 Single-atom site catalysts Interface regulation Electronic interactions Coordination environment Electrocatalytic reaction
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From basic researches to new achievements in therapeutic strategies of KRAS-driven cancers 被引量:2
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作者 Mahsa Saliani Razieh Jalal Mohammad Reza Ahmadian 《Cancer Biology & Medicine》 SCIE CAS CSCD 2019年第3期435-461,共27页
Among the numerous oncogenes involved in human cancers, KRAS represents the most studied and best characterized cancerrelated genes.Several therapeutic strategies targeting oncogenic KRAS(KRASonc) signaling pathways h... Among the numerous oncogenes involved in human cancers, KRAS represents the most studied and best characterized cancerrelated genes.Several therapeutic strategies targeting oncogenic KRAS(KRASonc) signaling pathways have been suggested,including the inhibition of synthetic lethal interactions, direct inhibition of KRASonc itself, blockade of downstream KRASonc effectors, prevention of post-translational KRASonc modifications, inhibition of the induced stem cell-like program, targeting of metabolic peculiarities, stimulation of the immune system, inhibition of inflammation, blockade of upstream signaling pathways,targeted RNA replacement, and oncogene-induced senescence.Despite intensive and continuous efforts, KRASonc remains an elusive target for cancer therapy.To highlight the progress to date, this review covers a collection of studies on therapeutic strategies for KRAS published from 1995 to date.An overview of the path of progress from earlier to more recent insights highlight novel opportunities for clinical development towards KRASonc-signaling targeted therapeutics. 展开更多
关键词 Direct inhibition downstream EFFECTORS oncogenic KRAS drug target sites small GTPASES signal TRANSDUCTION targeting synthetic lethal interactions therapeutic strategies
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Intrinsic properties of active sites for hydrogen production from alcohols without coke formation 被引量:1
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作者 Zhong He Xianqin Wang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2013年第3期436-445,共10页
The detailed reaction pathway and coke formation mechanism over Pt/metal oxide nanoparticles during the steam reforming of ethanol (SRE) at 300℃ were studied. The catalysts were prepared by incipient wetness impreg... The detailed reaction pathway and coke formation mechanism over Pt/metal oxide nanoparticles during the steam reforming of ethanol (SRE) at 300℃ were studied. The catalysts were prepared by incipient wetness impregnation method and were characterized with CO pulse chemisorption, BET surface measurement, oxygen adsorption, ethanol-TPD, NH3-TPD, and TPO. The SRE activity of the catalysts with steam/ethanol molar ratio of 3/1 was tested using a continuous fixed-bed reactor. Strong interaction between Pt and supports causes lower H2 production temperatures and no C2H4 formation, while weak interaction leads to C2H4 formation and strong bonded CO on Pt particles during ethanol- TPD. H2 production over Pt-based catalysts is mainly resulted from the decomposition and dehydrogenation of ethanol, and decarbonylation of acetaldehyde. Meanwhile, coke can be formed from acetaldehyde, acetone, C2H4 and CO. However, when the interaction between Pt and supports is weak, more coke is formed especially from acetone, C2H4 and CO. When the interaction is strong, no coke formation is observed due to high oxygen storage capacity of the catalyst. 展开更多
关键词 active sites HYDROGEN ALCOHOLS coke formation PT interaction
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4f^(N-1)5d energy levels of lanthanides:a quasi-angular-momentum approach and its application to Cs_2NaYF_6:Er^(3+) 被引量:1
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作者 马崇庚 江莎 +2 位作者 段昌奎 尹民 夏上达 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第5期1961-1967,共7页
The spin-orbit interaction of the 5d electron needs to be taken into account to give the proper energy structure for the 4fN-1 5d configuration of heavy lanthanide ions occupying a site with ligands forming an octahed... The spin-orbit interaction of the 5d electron needs to be taken into account to give the proper energy structure for the 4fN-1 5d configuration of heavy lanthanide ions occupying a site with ligands forming an octahedron. This paper derives theoretical results for the energy structure by treating the t2 orbitals as quasi p orbitals and then using angular-momentum coupling techniques. An analytic expression for the electric dipole absorption line strengths between 4fN multiplets and 4fN- 1 5d states is given in terms of various angular-momentum quantum numbers and re-coupling coefficients. The result is then applied to interpret the excitation spectrum of Cs2NaYF6:Er3+. Tbe high-spin and lowspin states of Cs2NaYF6:Er3+ are discussed in terms of the wavefunctions obtained by using the developed theoretical model. 展开更多
关键词 f-d transition octahedral site spin-orbit interaction coupling of angular momenta
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Influence of Zr, Ce, and La on Co_3O_4 catalyst for CO_2 methanation at low temperature 被引量:2
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作者 Yuwen Zhou Yuexiu Jiang +2 位作者 Zuzeng Qin Qinruo Xie Hongbing Ji 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第4期768-774,共7页
The Co3O4 and Zr-,Ce-,and La-Co3O4 catalysts were prepared,characterized,and applied to produce CH4 from CO2 catalytic hydrogenation in low temperature as 140–220℃.The results indicated that the addition of Zr,Ce,or... The Co3O4 and Zr-,Ce-,and La-Co3O4 catalysts were prepared,characterized,and applied to produce CH4 from CO2 catalytic hydrogenation in low temperature as 140–220℃.The results indicated that the addition of Zr,Ce,or La to the Co3O4 decreased the crystallite sizes of Co and the outer-shell electron density of Co^3+,and increased the specific surface area,which would provide more active sites for the CO2 methanation.Especially,the addition of Zr also changed the reducing state of Co3O4 via an obvious change in the interaction between Co3O4 and ZrO2.Furthermore,Zr doped into the Co3O4 increased the basic intensity of the weak and medium basic sites,as well as the amount of Lewis acid sites,and Bronsted acid sites were also found on the Zr-Co3O4 surface.The introduction of Zr,Ce,or La favored the production of CH4,and the Zr-Co3O4catalyst exhibited the highest CO2 conversion(58.2%)and CH4 selectivity(100%)at 200℃,and 0.5 MPa with a gaseous hourly space velocity of 18,000 ml·g^-1(cat)·h^-1,and the catalytic activity of CO2methanation for the Zr-,Ce-,and La-Co3O4 exhibited more stable than Co3O4 in a 20-h reaction. 展开更多
关键词 CO2 hydrogenation Methanation Co3O4 catalyst Cobalt-zirconium interaction Basic sites
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Stable CuO/La_(2)Sn_(2)O_(7) catalysts for soot combustion:Study on the monolayer dispersion behavior of CuO over a La_(2)Sn_(2)O_(7) pyrochlore support 被引量:2
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作者 Xiaohui Feng Rui Liu +6 位作者 Xianglan Xu Yunyan Tong Shijing Zhang Jiacheng He Junwei Xu Xiuzhong Fang Xiang Wang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2021年第3期396-408,共13页
To understand the dispersion behavior of metal oxides on composite oxide supports and with the expectation of developing more feasible catalysts for soot oxidation,CuO/La_(2)Sn_(2)O_(7)samples containing varied CuO lo... To understand the dispersion behavior of metal oxides on composite oxide supports and with the expectation of developing more feasible catalysts for soot oxidation,CuO/La_(2)Sn_(2)O_(7)samples containing varied CuO loadings were fabricated and characterized by different techniques and density functional theory calculations.In these catalysts,a spontaneous dispersion of CuO on the La_(2)Sn_(2)O_(7)pyrochlore support formed,having a monolayer dispersion capacity of 1.90 mmol CuO/100 m^(2) La_(2)Sn_(2)O_(7)surface.When loaded below this capacity,CuO exists in a sub-monolayer or monolayer state.X-ray photoelectron spectroscopy(XPS),Raman spectroscopy,and Bader charge and density of states analyses indicate that there are strong interactions between the sub-monolayer/monolayer CuO and the La_(2)Sn_(2)O_(7)support,mainly through the donation of electrons from Cu to Sn at the B-sites of the structure.In contrast,Cu has negligible interactions with La at the A-sites.This suggests that,in composite oxide supports containing multiple metals,the supported metal oxide interacts preferentially with one kind of metal cation in the support.The Raman,in situ diffuse reflectance infrared Fourier transform spectroscopy,and XPS results confirmed the formation of both O2^(-)and O2^(2-)as the active sites on the surfaces of the CuO/La_(2)Sn_(2)O_(7)catalysts,and the concentration of these active species determines the soot combustion activity.The number of active oxygen anions increased with increase in CuO loading until the monolayer dispersion capacity was reached.Above the monolayer dispersion capacity,microsized CuO crystallites formed,and these had a negative effect on the generation of active surface oxygen sites.In summary,a highly active catalyst can be prepared by covering the surface of the La_(2)Sn_(2)O_(7)support with a CuO monolayer. 展开更多
关键词 CuO/La_(2)Sn_(2)O_(7)catalyst Soot combustion DFT calculations Preferential interaction Monolayer dispersion on pyrochlore support Active O2^(-)and O2^(2-)sites
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Tripartite states Bell-nonlocality sudden death in a spin environment with multisite interaction 被引量:1
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作者 谢利军 张登玉 +3 位作者 汪新文 詹孝贵 唐世清 高峰 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第8期16-22,共7页
Tis paper demonstrates that multipartite Bell-inequality violations can be fully destroyed in a finite time in three- qubit states coupled to a general XY spin-chain with a three-site interaction environment. The Merm... Tis paper demonstrates that multipartite Bell-inequality violations can be fully destroyed in a finite time in three- qubit states coupled to a general XY spin-chain with a three-site interaction environment. The Mermin Ardehali- Belinksii-Klyshko inequality is used to detect the degree of nonlocality, as measured by the extent of their violations. The effects of system-environment couplings, the size of degrees of freedom of the environment and the strength of the three-site interaction on the Bell-inequality violations are given. The results indicate that the Bell-inequality violations of the tripartite states will be completely destroyed by decoherence under certain conditions for the GHZ state. The decoherence-free subspaces of our model are identified and the entanglement of quantum states is also discussed. 展开更多
关键词 Bell-type inequality Bell-nonlocality sudden death three-site interaction
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Structure-function relationship in viral RNA genomes: The case of hepatitis C virus
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作者 Cristina Romero-López Alfredo Berzal-Herranz 《World Journal of Medical Genetics》 2014年第2期6-18,共13页
The acquisition of a storage information system beyond the nucleotide sequence has been a crucial issue for the propagation and dispersion of RNA viruses. This system is composed by highly conserved, complex structura... The acquisition of a storage information system beyond the nucleotide sequence has been a crucial issue for the propagation and dispersion of RNA viruses. This system is composed by highly conserved, complex structural units in the genomic RNA, termed functional RNA domains. These elements interact with other regions of the viral genome and/or proteins to direct viral translation, replication and encapsidation. The genomic RNA of the hepatitis C virus(HCV) is a good model for investigating about conserved structural units. It contains functional domains, defined by highly conserved structural RNA motifs, mostly located in the 5'-untranslatable regions(5'UTRs) and 3'UTR, but also occupying long stretches of the coding sequence. Viral translation initiation is mediated by an internal ribosome entry site located at the 5' terminus of the viral genome and regulated by distal functional RNA domains placed at the 3' end. Subsequent RNA replication strongly depends on the 3'UTR folding and is also influenced by the 5' end of the HCV RNA. Further increase in the genome copy number unleashes the formation of homodimers by direct interaction of two genomic RNA molecules, which are finally packed and released to the extracellular medium. All these processes, as well as transitions between them, are controlled by structural RNA elements that establish a complex, direct and long-distance RNARNA interaction network. This review summarizes current knowledge about functional RNA domains within the HCV RNA genome and provides an overview of the control exerted by direct, long-range RNA-RNA contacts for the execution of the viral cycle. 展开更多
关键词 Functional RNA domain Cis-acting replicating element Hepatitis C virus Internal ribosome entry site RNA-RNA interaction Untranslatable region
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