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A Note on Queueing System M/M/1

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Journal of Mathematical Research with Applications 1992年第2期 313-315页

作者： He Qiming (Inst. of Appl. Math., Chinese Academy of sciences, Beijing, china)

A new formula is given for the queue length distribution functions of queueingsystem M/M/*** on this formula and renewal theory,a new and simple proof ofthe ergodicity of queueing system M/M/1 is given.

关键词： A Note on Queueing System M/M/1 length

Progress on Solar Physics in china During 2004 - 2006

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空间科学学报 2006年第Z1期26卷 122-137页

作者： YAN Yihua AI Guoxiang National Astronomical Observatories Chinese Academy of sciences Beijing 100012 China National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

The solar physics studies in china during 2004-2006 from solar interior to solar atmospheres and solar-interplanetary space are summarized. These researches are arranged under the topics of solar interior, photosphere, chromosphere and transition region, corona, flares and CMEs (and the associated radio bursts, X-ray/γ-ray bursts and particle acceleration), solar wind, solar cycle, and ground-based instrumentation.

关键词： Solar physics

INVESTIGATION OF BONDING IN NANO-SiO_(2) BY Si L_(2,3) X-RAY ABSORPTION NEAR-EDGE STRUCTURE SPECTROSCOPY

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Acta Metallurgica Sinica(English Letters) 2001年第6期14卷 473-478页

作者： Z.Y. Wu, K. Ibrahim, G. Li, J. Zhang, F.Q. Liu, M.I Abbas, R. Hu, H.J. Qian and F.Q. Tang ( Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, The Chinese Academy of sciences, Beijing 100039, china) ( Laboratori Nazionali di Frascat Inst. of High Energy Phys. Chinese Acad. of Sci. Beijing 100039 China

The Si L2,3 X-ray absorption near-edge structure (XANES) can be used to probe thelocal structure around Si and derive electronic information of the unoccupied s- andd-like partial density of states in nano-size SiO2. We present Si L2,3-edge for threedifferent size silicates acquired by total electron yield (TEY) at the photoemission sta-tion of Beijing Synchrotron Radiation Facility (BSRF). The Si L2,3-edge spectra areinterpreted based on ab initio full multiple-scattering (MS) calculation. The Si L2.3-edge of nano-size materials has XANES similar to that of a-quartz. The similaritiesbetween the Si L2.3-edge shapes attest to a common molecular-orbital picture of theirSi-O bonding and the same coordination state. However, a considerable broadeningof Si L2,3-edge XANES spectra as decrease of particle size is also an indicative ofpolyhedral distortions.

关键词： multiple scattering calculation X-ray absorption nano particle electronic structure

Incremental 4D-VAR assimilation scheme based on Lorenz model

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Acta Oceanologica Sinica 2008年第z1期27卷 93-100页

作者： WANG Xidong XU Dongfeng XU Xiaohua State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of Oceanography State Oceanic Administra-tion Hangzhou 310012China State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of Oceanography State Oceanic Administra-tion Hangzhou 310012China State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of Oceanography State Oceanic Administra-tion Hangzhou 310012China

Four-dimensional variational(4D-VAR) data assimilation method is a perfect data assimilation solution in theory, but the computational issue is quite difficult in operational *** incremental 4D-VAR assimilation scheme is set up in order to reduce the computational cost. It is shown that the accuracy of the observations, the length of the assimilation window and the choice of the first guess have an important influence on the assimilation outcome through the contrast experiment. Compared with the standard 4D-VAR assimilation scheme, the incremental 4D-VAR assimilation scheme shows its advantage in the computation speed through an assimilation experiment.

关键词： 4D-VAR assimilation,incremental 4D-VAR assimilation Lorenz model

Two gap-free reference genomes and a global view of the centromere architecture in rice

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Molecular Plant 2021年第10期14卷 1757-1767页

作者： Jia-Ming Song Wen-Zhao Xie Shuo Wang Yi-Xiong Guo Dal-Hoe Koo Dave Kudrna Chenbo Gong Yicheng Huang Jia-Wu Feng Wenhui Zhang Yong Zhou Andrea Zuccolo Evan Long Seunghee Lee Jayson Talag Run Zhou Xi-Tong Zhu Daojun Yuan Joshua Udall Weibo Xie Rod AWing Qifa Zhang Jesse Poland Jianwei Zhang Ling-Ling Chen National Key Laboratory of Crop Genetic Improvement Huazhong Agricultural UniversityWuhan 430070China College of Life science and Technology Guangxi UniversityNanning 530004China Wheat Genetics Resource Center Department of Plant PathologyKansas State UniversityManhattanKSUSA Arizona Genomics Institute School of Plant SciencesUniversity of ArizonaTucsonAZ 85721USA Center for Desert Agriculture Biological and Environmental Sciences&Engineering Division(BESE)King Abdullah University of Science and Technology(KAUST)Thuwal 23955-6900Saudi Arabia Plant and Wildlife science Department Brigham Young UniversityProvoUT 84602USA International Rice Research Institute(IRRI) Strategic InnovationLos Baños4031 LagunaPhilippines Crop Germplasm Research Unit USDA-ARS2881 F&B RoadCollege StationTX 77845USA

Rice(Oryza sativa),a major staple throughout the world and a model system for plant genomics and breeding,was the first crop genome sequenced almost two decades ***,reference genomes for all higher organisms to date contain gaps and missing ***,we report the assembly and analysis of gap-free reference genome sequences for two elite *** xian/indica rice varieties,Zhenshan 97 and Minghui 63,which are being used as a model system for studying heterosis and ***-free reference genomes provide the opportunity for a global view of the structure and function of *** show that all rice centromeric regions share conserved centromere-specific satellite motifs with different copy numbers and *** addition,the similarity of CentO repeats in the same chromosome is higher than across chromosomes,supporting a model of local expansion and *** genomes have over 395 non-TE genes located in centromere regions,of which∼41%are actively *** large structural variants at the end of chromosome 11 affect the copy number of resistance genes between the two *** availability of the two gap-free genomes lays a solid foundation for further understanding genome structure and function in plants and breeding climate-resilient varieties.

关键词： rice genome ZS97 MH63 hybrid rice centromere architecture

Observation of Coulomb blockade and ballistic tunneling in graphene single electron transistor

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science china(Physics,Mechanics & Astronomy) 2012年第1期55卷 7-10页

作者： TAN ZhenBing LIU GuangTong LU Li YANG ChangLi Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China

A square graphene single electron transistor （SET） was defined with two side gates, and its transport was studied at low temperature at T = 2 K. At zero magnetic field, Coulomb blockade oscillations were clearly observed near the Dirac point of this device. At high magnetic field, in the quantum Hall regime, we observed ballistic tunneling of the carders through the graphene SET, contrary to the Coulomb blockades observed while approaching the vicinity of the Dirac point.

关键词： graphene single electron transistor Coulomb blockade tunneling quantum Hall state

Analysis of Laser-generated Rayleigh wave on viscoelastic materials

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Chinese Journal of Acoustics 2008年第1期27卷 57-64页

作者： HAN Qingbang QIAN Menglu Department of Computer and Information Engineering Hehai University Changzhou 213022 Department of Information Technology Technology Institute of Changzhou Changzhou 213002 Institute of Acoustics Tongji University Shanghai 200092

In order to understand the viscoelasticity of material, this research has been conducted to study the propagation characteristics of viscoelastic Rayleigh wave theoretically. A model is presented for the pulsed laser generation of ultrasound on viscoelastic medium surface. Referred to the Kelvin model, the frequency equation and the normal displacement of viscoelastic Rayleigh wave were derived, the influence of the viscoelastic modulus on dispersion and attenuation was discussed. From the theoretical calculation, it is shown that the effect of viscoelasticity on the attenuation of Rayleigh wave is more than that on its dispersion. In the case of a weak viscosity, the attenuation of viscoelastic Rayleigh wave is directly proportional to viscosity modulus; the effect of shear viscosity on the attenuation is much more than that of bulk viscosity. The transient response of viscoelastic Rayleigh wave was also simulated using Laplace and Hankel inversion transform, which are showed in good agreement with the theoretic predictions. The model provides a useful tool for the determination of viscoelastic parameters of medium.

关键词： wave Analysis of Laser-generated Rayleigh wave on viscoelastic materials

镁助剂改性Pd/Al2O3甲烷催化燃烧催化剂:Mg/Al物质的量比对催化剂载体及活性物种形成的影响

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燃料化学学报 2019年第10期47卷 1235-1244页

作者：詹瑛瑛康亮周玉常蔡国辉陈崇启江莉龙福州大学化肥催化剂国家工程研究中心

本文研究了系列不同含量镁助剂改性的Pd/Al2O3催化剂的甲烷催化燃烧反应。研究表明,随着镁添加量的增加,载体由Al2O3转变为尖晶石型MgAl2O4,进一步增加Mg/Al物质的量比至3∶1时,形成了Mg(Al)Ox固溶体;催化剂中活性相Pd物种以金属Pd,PdOx... 详细信息

本文研究了系列不同含量镁助剂改性的Pd/Al2O3催化剂的甲烷催化燃烧反应。研究表明,随着镁添加量的增加,载体由Al2O3转变为尖晶石型MgAl2O4,进一步增加Mg/Al物质的量比至3∶1时,形成了Mg(Al)Ox固溶体;催化剂中活性相Pd物种以金属Pd,PdOx或Pd-载体复合氧化物形式存在,各物种的相对含量以及PdPdO间的转化能力存在一定的差异。PdOx物种表现为具有较高的低温活性,而金属Pd和Pd-载体复合氧化物的高温活性较好。当Mg/Al物质的量比为1∶3时,催化剂的PdPdO转化能力最强,表现出了最高的甲烷催化燃烧反应活性。

关键词：甲烷催化燃烧钯催化剂镁铝尖晶石镁铝固溶体

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骨髓源干细胞在脑组织的迁移和分化

神经科学通报 2005年第6期21卷 425-431页

作者：邹西峰徐群渊首都医科大学北京神经科学研究所北京市神经再生修复研究重点实验室

骨髓源干细胞(BONE MARROW-DERIVED STEM CELLS,BMDSCS)能否迁移至脑组织并分化为神经胶质细胞和神经细胞是近年来成体干细胞研究的热点领域。有一些学者采用Y染色体和GFP基因作为骨髓源细胞标记物,通过血行输入受体动物后,在脑组织内... 详细信息

骨髓源干细胞(BONE MARROW-DERIVED STEM CELLS,BMDSCS)能否迁移至脑组织并分化为神经胶质细胞和神经细胞是近年来成体干细胞研究的热点领域。有一些学者采用Y染色体和GFP基因作为骨髓源细胞标记物,通过血行输入受体动物后,在脑组织内发现了标记阳性细胞,并证实这些细胞有向神经胶质细胞和神经细胞分化的趋势;另有一些学者也采用GFP基因作为细胞标记物,但在受体动物脑组织并未发现标记阳性细胞。这些实验结果差异可能与观察时间长短、细胞标记方法和神经组织中标记基因沉默事件有关。就迁移到脑组织的BMDSCS 是否与宿主神经细胞整合的问题,有研究认为存在转分化(TRANSDIFFERENTIATION)机制,也有实验发现BMDSCS与小脑PURKINJE神经元之间有细胞融合现象。细胞转分化和细胞融合有可能是中胚层来源的BMDSCS向神经外胚层细胞变化的两种必要机制。讨论这些问题对阐明神经细胞的新老更替、损伤和修复机制是很有意义的。

关键词：骨髓源干细胞神经胶质神经元转分化细胞融合