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Quantum Chemical Studies on Proteins in the Reaction Center of Rhodobacter sphaeroides 被引量:1
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作者 徐红 马淑华 +3 位作者 沈玲玲 张晓东 张兴康 张启元 《Acta Botanica Sinica》 CSCD 2001年第6期565-570,共6页
The electronic structure of protein chains L and M in photosynthetic reaction center (PRC) of Rhodobacter sphaeroides (Van Niel) Imhoff, Truper et Pfennig) was studied by using the Overlapping Dimer Approximation meth... The electronic structure of protein chains L and M in photosynthetic reaction center (PRC) of Rhodobacter sphaeroides (Van Niel) Imhoff, Truper et Pfennig) was studied by using the Overlapping Dimer Approximation method and the Extended Negative Factor Counter method at ab initio level. The result indicated that: (1) Amino acid residues, the molecular orbitals of which composed the main components of frontier orbitals of protein chain L (M), are located at the random coil areas of chain L (alpha helix areas of chain M). Since the random coil is flexible and more easy to change its conformation in the electron transfer process and to reduce the energy of the system, and the structure of the alpha helix is reletively stable, this difference might be one of the causes for the electron transfer in photosynthetic reaction center (PRC) only takes place along the L branch. (2) The His residues which axially coordinated to the 'special pair' P and accessory chlorophyll molecules (ABChls) are essentially important for the E-LUMO levels of P and ABChl. But, the corresponding molecular orbitals of these His residues do not appear in the composition of frontier orbitals of protein chains. It means that the interaction between pigment molecules and protein chains do not influence the contribution to the frontier orbitals of protein chains explicitly, but influences the corresponding E-LUMO levels significantly. 展开更多
关键词 photosynthetic reaction center Rhodobacter sphaeroides electronic structure of protein ab initio Extended negative Factor Counter method (ENFC)
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Evaluation of forest disturbance in south-west Zabaikalia (East Siberia) 被引量:1
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作者 Т.А.MIKHAILOVA L.V.AFANASIEVA +1 位作者 O.V.KALUGINA О.V.SHERGINA 《Forestry Studies in China》 CAS 2013年第4期332-339,共8页
The forest estate in south-west Zabaikalia, a territory included in the Lake Baikal catchment area, has been investigated. For this purpose we have used both data of our own studies and monitoring data of environmenta... The forest estate in south-west Zabaikalia, a territory included in the Lake Baikal catchment area, has been investigated. For this purpose we have used both data of our own studies and monitoring data of environmental protection bodies. It shows that in our study area, fires, fellings, entomo-parasites and air pollution are the major negative factors affecting the state of the forest. In the period from 2003 to 2008 fires were registered in the area of over 500 thousand ha, pest foci in the forests covering an area of over 330 thousand ha, where almost 5 million m3wood was cut in an area of about 43 thousand ha. The total area of forests in our study affected by air pollution amounts to about 700 thousand ha. According to the results, forest pollution in the territory is concentrated in the vicinity of large-scale industrial complexes, for distances up to about 40 km. The total area of forests weakened by air pollution amounts to about 2 million ha. 展开更多
关键词 south-west Zabaikalia Lake Baikal catchment area forest state negative factors
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Analysis of the causes of formation of negative loss factors 被引量:4
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作者 SUN Zhaohui SUN Jincai WANG Chong and SHENG Meiping(Institute of Acoustic Engineering, Northwestern Polytechnical University Xi’an, 710072) 《Chinese Journal of Acoustics》 1996年第3期239-246,共8页
Based on classical energy balance equations for two coupled systems in Statistical Energy Analyis (SEA), the possibility of causing negative loss factors in measuring SEA parameters by using the equations is analyzed.... Based on classical energy balance equations for two coupled systems in Statistical Energy Analyis (SEA), the possibility of causing negative loss factors in measuring SEA parameters by using the equations is analyzed. The physical causes of formation of negative loss factors are theoretically invstigated by vibration analysis of the two non-conservatively coupled oscillator sets. Mom the analytical results, it is shown that the necessary condition of foedng negatbo loss factors is that the coupling of the coupled systems is non-conservative and strong and the suffiient condition is that the excitation frequency of the external force is not equal to the natural frequencies of the two oscillators at the sam tAne or the parameters of the two oscillators are much different. The absolute values of the negative loss factors increase with the increase of the coupling pararneters. 展开更多
关键词 SEA negative loss factor SEA parameters
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Negative regulation of resistance protein-mediated immunity by master transcription factors SARD_1 and CBP60g 被引量:2
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作者 tongjun sun wanwan liang +1 位作者 yuelin zhang xin li 《Journal of Integrative Plant Biology》 SCIE CAS CSCD 2018年第11期1023-1027,共5页
Summary Salicylic acid (SA) is an essential defence hormone in plants. Upon pathogen infection, induced biosynthesis of SA is mediated by Isochorismate synthase 1 (ICS1), whose gene transcription is controlled mai... Summary Salicylic acid (SA) is an essential defence hormone in plants. Upon pathogen infection, induced biosynthesis of SA is mediated by Isochorismate synthase 1 (ICS1), whose gene transcription is controlled mainly through two redundant transcription factors, SAR Deficient 1 (SARD0 and Calmodulin- binding protein 6o-like g (CBP60g). 展开更多
关键词 SNC negative regulation of resistance protein-mediated immunity by master transcription factors SARD1 and CBP60g SA Figure CBP
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Wave Propagation Characteristics in Thick Conventional and Auxetic Cellular Plates 被引量:1
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作者 Xiaojian Xu Zichen Deng 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2016年第2期159-166,共8页
Based on Mindlin plate models and Kirchhoff plate models,this study was concerned with the wave propagation characteristics in thick conventional and auxetic cellular structures,with the objective to clarify the effec... Based on Mindlin plate models and Kirchhoff plate models,this study was concerned with the wave propagation characteristics in thick conventional and auxetic cellular structures,with the objective to clarify the effects of negative Poisson's ratio,shear factor and orthotropic mechanical properties on the dynamic behaviors of thick plates.Numerical results revealed that the predictions using variable shear factor in Mindlin plate models resulted in high wave frequencies,which were more significant for plates with negative values of Poisson's ratio.The present study can be useful for the design of critical applications by varying the values of Poisson's ratio. 展开更多
关键词 auxetic cellular structure plate frequency shear factor negative Poisson's ratio
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