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Influence of ^(12)C^(6+) ion irradiation on mutant avermitilis

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Chinese physics C 2012年第11期36卷 1140-1144页

作者：王曙阳陈积红李文建梁剑平薄永恒马晓琪刘敬 epartment of biology physics Institute of Modern PhysicsChinese Academy of Sciences Lanzhou University Gansu Agricultural University

The effects of 12C＋6 ion irradiation on colony morphology and mycelia morphology, as well as on mutation rate have been studied in the B1a high-product strains （ZJAV-Y1-203） mutated by heavy ion irradiation and compared with that in the original strain （ZJAV-A-1）. After irradiating the rate of a straw hat colony type having a high ability of producing B1a in ZJAV-Y1-203 strains was higher than that found in ZJAV-A-1 strains. When strains were cultured in a liquid medium for 24 hours, the mycelium becoming thinner could be observed in all of the irradiated ZJAV- Y1-203 groups, but only in the ZJAV-A-1 groups irradiated at the dose of 50 Gy or more. The early growth of mycelium was inhibited in the ZJAV- Y1-203 group irradiated with a high dose. The highest positive mutation rate （23.5%） of ZJAV - Y1 - 203 was reached at the lower dose of 30 Gy while the highest positive mutation rate of 34.2% in ZJAV-A-1 appeared at 50 Gy. These results indicate that the effects of heavy ion irradiation still exist even in the mutated Streptomyces avermitilis, and only the dose is lower and the effects not so strong compared with the one that is first irradiated with optimized heavy ion doses. This is evidence of the one directional mutation being controlled by many more factors in a organism.

关键词： Streptomyces avermitilis 12C+6 ion beam progress irradiation influence

Gravitation Without Singularity

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Chinese physics Letters 2000年第2期17卷 82-84页

作者： CHEN Guang epartment of Electronics Shantou UniversityShantou 515063 East China Institute for Theoretical physics Shanghai 200237

The coupled Einstein-scalar-vector field equations are found, and their static spherically symmetric solutions are derived under the consideration of self-gravitational interaction of scalar field and proved to be sin... 详细信息

关键词： energy scalar singularity

Scalar Susceptibility of QCD from Dyson-Schwinger Approach

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Communications in Theoretical physics 2008年第1期49卷 189-192页

作者： WU Kong-Ping SHI Yuan-Mei SUN Wei-Min PING Jia-Lun ZONG Hong-Shi epartment of physics Nanjing Normal UniversityNanjing 210097 China Depnrtment of physics Nnnjing University Nnnjing 210093 Chinn joint Center for Particle Nuclear Physics and Cosmology Nanjing 210093 China

In quantum chromodynamics （QCD）, the scalar susceptibility represents the modification of the quark condensate, to a small perturbation of the parameter responsible for the explicit breaking of the symmetry, i.e., the current quark mass. By studying the linear response of the dressed quark propagator to the presence of a nonzero quark mass, we derive a model-independent formula for the scalar susceptibility, which contains the dressed quark propagator G（p） and the dressed scalar vertex F（p, 0）. The numerical values of the scalar susceptibility Xs are calculated within the framework of the rainbow-ladder approximation of the Dyson-Schwinger approach by employing two typical forms of model gluon propagator.

关键词： scalar susceptibility explicit and dynamical chiral symmetry breaking Dyson-Schwinger equations

Dioxygen oxidation of hydrocarbons by a methane monooxygenase-like system: diiron complex-O_2-Zn/HOAc-MV^(2+)

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Science China Chemistry 1999年第2期42卷 131-137页

作者：魏俊发何地平俞贤达 1. epartment of Chemistry Shaanxi Normal University 710062 Xi’an China 2. Lanzhou Institute of Chemical physics Chinese Academy of Sciences 730000 Lanzhou China

The activation of dioxygen and incorporation into hydrocarbons have been achieved under mild conditions by a methane monooxygenase (MMO)-like system using a dinuclear iron complex [Fe2Dhist(OAc)2] BPh4 ·3H2O as the model complex, zinc powder as the electron donor, HOAc as the proton source and methylviologen as the electron transfer agent. The results show that styrene is oxygenated predominantly to styrene oxide (1 396 mol/100 mol of the Fe2 complex), benzaldehyde (16160) and acetophenone (986), and cyclohexane to cyclohexanol (9370) and cyclo-hexanone (2670). EPR studies indicate that the hypervalent ironoxo spiecs FeⅣFeⅣ=O, derived from FeⅢFeⅢ core via reduction, O2-binding and protonation, is the active intermediate which inserts the activated oxygen atom into C=C or C-H bond giving each product. The system closely resembles MMO and its close relative hemerythrin in the aspects of reaction phenomena, EPR characteristics and product distributions. The Mn2 analog cmplex、 Fe-Zn het-erodinuclear complex and mononuclear iron complex show no catalytic activity, indicating that dinuclear iron core is in-despansable to catalytic activity.

关键词： methane monooxygenase model system diiron complex biomimetic catalysis selective oxidation dioxygen activation.

Mechanism of Spatiotemporal Distribution of Laser Ablated Materials

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Chinese physics Letters 2009年第1期26卷 176-179页

作者：徐荣青崔一平陆健倪晓武 Department of Electronic Engineering Southeast University Nanjing 210096 College of Optoeleetronic Engineering Nanjing University of Posts and Telecommunications Nanjing 210003 epartment of Applied physics Nanjing University of Science and Technology Nanjing 210094

Interaction between subsequent laser and ablated materials in laser processing changes the laser spatiotemporal distribution and has influences on the efficiency and quality of laser processing. The theoretical and experimental researches on transportation behaviour of ablated materials are provided. It is shown that the velocity distribution of ablated materials is determined by ablation mechanism. The transportation behaviour of ablated materials is controlled by diffusion mechanism and light field force during laser pulse duration while it is only determined by diffusion mechanism when the laser pulse terminates. In addition, the spatiotemporal distribution of ablated materials is presented.

关键词： field emission molybdenum dioxide enhancement factor

Interest-Driven Model for Human Dynamics

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Chinese physics Letters 2010年第4期27卷 250-252页

作者：尚明生陈冠雄戴双星汪秉宏周涛 Web Sciences Center School of Computer Science and Engineering University of Electronic Science and Technology of China Chengdu 610054 epartment of Modern physics University of Science and Technology of China Hefei 230026 The Research Center for Complex System Science University of Shanghai for Science and Technology Shanghai 200093 Department of physics University of Fribourg Chemin du Musee 3 1700 Fribourg Switzerland

Empirical observations indicate that the interevent time distribution of human actions exhibits heavy-tailed features. The queuing model based on task priorities is to some extent successful in explaining the origin of such heavy tails, however, it cannot explain all the temporal statistics of human behavior especially for the daily entertainments. We propose an interest-driven model, which can reproduce the power-law distribution of interevent time. The exponent can be analytically obtained and is in good accordance with the simulations. This model well explains the observed relationship between activities and power-law exponents, as reported recently for web-based behavior and the instant message communications.

关键词： Environmental and Earth science Statistical physics and nonlinear systems

Effect of Pyrolysis Atmosphere on Ferroelectric Properties of Bi3.25La0.75Ti3O12 Films Prepared by Sol-Gel Method

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Chinese physics Letters 2009年第3期26卷 258-261页

作者：李建军于军吴云翼李佳王耕波 epartment of Electronic Science and Technology Huazhong University of Science and Technology Wuhan 430074

The effect of pyrolysis atmosphere is investigated for Bi3.25 La0.75 Ti3O12 （BLT） films prepared on Pt/TiO2/SiO2/p-Si（100substrates by sol-gel processes. The pyrolysis is carried out at 400℃ for 20 min under air or O2 atmosphere and the successive anneal is performed at 700℃ for 30min under O2 atmosphere. The pyrolysis under O2 is enough for complete removal of organic species, however after pyrolysis under air, carbon and hydrogen atomic species as organic fragment are partly remained in the film. This incomplete removal of organic fragments affects the grain growth and cause more defects in the film or between interfaces during the annealing for the crystallization of BLT film. The growth direction and grain size of the BLT film is revealed to affect ferroelectric properties. The remanent polarization PTfor the BLT films of pyrolysis in O2 and air are measured to be 18.85μC/cm^2 and 12.56μC/cm^2,respectively. The defects degrade the fatigue property dramatically for the film of pyrolysis in air. It can be concluded that the pyrolysis is an important procedure to control ferroeleetrie properties.

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Relations between integrated and monochromatic luminosities of flat-spectrum radio quasars

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Research in Astronomy and Astrophysics 2011年第4期11卷 401-410页

作者： Zhi-Fu Chen Zhao-Yu Chen Yi-Ping Qin Min-Feng Gu Lian-Zhong LU Cheng-Yue Su You-Bing Li Ye Chen Center for Astrophysics Guangzhou University Guangzhou 510006 China epartment of Astronomy Peking University Beijing 100871 China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China physics Department Guangxi University Nanning 530004 China Department of physics Guangdong University of-Technology Guangzhou 530004 China Guangzhou City Construction College Guangzhou 530004. China

We employ a sample of 362 flat-spectrum radio quasars （FSRQs） to calculate their integrated luminosities by integrating the spectral energy distribution （SED） constructed with multi-band （radio, IR, optical, UV and X-ray） data. We compare these luminosities with those estimated from monochromatic luminosities by multi- plying them by the conventional bolometric correction factors. Our analysis shows that the integrated luminosities calculated from the SED are much larger than the bolometric luminosities estimated from monochromatic luminosities. Their departing behavior tightly correlates with radio luminosities. The relations between integrated and monochromatic luminosities are explored, which are regarded as empirical rela- tions that might be more suitable to be applied to estimate integrated luminosities of FSRQs from their monochromatic luminosities.

关键词： methods statistical -- galaxies active -- galaxies jets

Enhancement of pacemaker induced stochastic resonance by an autapse in a scale-free neuronal network

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Science China(Technological Sciences) 2016年第3期59卷 364-370页

作者： YILMAZ Ergin BAYSAL Veli PERC Matjaz OZER Mahmut epartment of Biomedical Engineering Engineering Faculty bülent Ecevit University Zonguldak 67100 Turkey Department of physics Faculty of Sciences King Abdulaziz University Jeddah 21431 Saudi Arabia Faculty of Natural Sciences and Mathematics University of Maribor Korogka cesta 160 Maribor SI-2000 Slovenia Department of Electrical and Electronics Engineering Engineering Faculty bülent Ecevit University Zonguldak 67100 Tarkey

An autapse is an unusual synapse that occurs between the axon and the soma of the same neuron. Mathematically, it can be described as a self-delayed feedback loop that is defined by a specific time-delay and the so-called autaptic coupling strength. Recently, the role and function of autapses within the nervous system has been studied extensively. Here, we extend the scope of theoretical research by investigating the effects of an autapse on the transmission of a weak localized pacemaker activity in a scale-free neuronal network. Our results reveal that by mediating the spiking activity of the pacemaker neuron, an autapse increases the propagation of its rhythm across the whole network, if only the autaptic time delay and the autaptic coupling strength are properly adjusted. We show that the autapse-induced enhancement of the transmission of pacemaker activity occurs only when the autaptic time delay is close to an integer multiple of the intrinsic oscillation time of the neurons that form the network. In particular, we demonstrate the emergence of multiple resonances involving the weak signal, the intrinsic oscillations, and the time scale that is dictated by the autapse. Interestingly, we also show that the enhancement of the pacemaker rhythm across the network is the strongest if the degree of the pacemaker neuron is lowest. This is because the dissipation of the localized rhythm is contained to the few directly linked neurons, and only afterwards, through the secondary neurons, it propagates further. If the pacemaker neuron has a high degree, then its rhythm is simply too weak to excite all the neighboring neurons, and propagation therefore fails.

关键词： autapse self-delayed feedback neuron channel noise scale-free network