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| 1 | Developing land use scenario dynamics model by the integration of system dynamics model and cellular automata model显示文摘Modeling land use scenario changes and its potential impacts on the structure and function of the ecosystem in the typical regions are helpful to understanding the interactive mechanism between land use system and ecological system. A Land Use Scenario Dynamics (LUSD) model by the integration of System Dynamics (SD) model and Cellular Automata (CA) model is developed with land use scenario changes in northern China in the next 20 years simulated in this paper. The basic idea of LUSD model is to simulate the land use scenario de-mands by using SD model at first, then allocate the land use scenario patterns at the local scale with the considerations of land use suitability, inheritance ability and neighborhood effect by using CA model to satisfy the balance between land use scenario demands and supply. The application of LUSD model in northern China suggests that the model has the ability to reflect the complex behavior of land use system at different scales to some extent and is a useful tool for assessing the potential impacts of land use system on ecological system. In addition, the simulated results also indicate that obvious land use changes will take place in the farming-pastoral zone of northern China in the next 20 years with cultivated land and urban land being the most active land use types. | HE Chunyang, SHI Peijun, CHEN Jin, Li Xiaobing, PAN Yaozhong, LI Jing, LI Yuechen & LI Jinggang Key Laboratory of Environmental Change and Natural Disaster, Ministry of Education of China, Beijing Normal University College of Resources Science & Technology, Beijing Normal University, Beijing 100875, China | 2005 | Science China Earth Sciences2005，48，11： | 21 |
| 2 | PARylation regulates stress granule dynamics, phase separation, and neurotoxicity of disease-related RNA-binding proteins显示文摘Mutations in RNA-binding proteins (RBPs) localized in ribonucleoprotein (RNP) granules, such as hnRNP A1 and TDP-43, promote aberrant protein aggregation, which is a pathological hallmark of various neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Protein posttranslational modifications (PTMs) are known to 佗gulate RNP granules. In this study, we investigate the function of poly(ADP-ribosyl)ation (PARylation), an important PTM involved in DNA damage repair and cell death, in RNP granule-related neurodegeneration. We reveal that PARylation levels are a major regulator of the assembly-disassembly dynamics of RNP granules containing disease-related RBPs, hnRNP A1 and TDP-43. We find that hnRNP A1 can both be PARylated and bind to PARylated proteins or poly(ADP-ribose)(PAR). We further uncover that PARylation of hnRNP A1 at K298 controls its nucleocytoplasmic transport, whereas PAR-binding via the PAR-binding motif (PBM) of hnRNP Al regulates its association with stress granules. Moreover, we reveal that PAR not only dramatically enhances the liquid-liquid phase separation of hnRNP A1, but also promotes the co-phase separation of hnRNP A1 and TDP-43 in vitro and their interaction in vivo. Finally, both genetic and pharmacological inhibition of PARP mitigates hnRNP Al- and TDP-43-mediated neurotoxicity in cell and Drosophila models of ALS. Together, our findings suggest a novel and crucial role for PARylation in regulating the dynamics of RNP granules, and that dysregulation in PARylation and PAR levels may con tribute to ALS disease pathoge nesis by promoting protei n aggregation. | Yongjia Duan Aiying Du Jinge Gu Gang Duan Chen Wang Xinrui Gui Zhiwei Ma Beituo Qian Xue Deng Kai Zhang Le Sun Kuili Tian Yaoyang Zhang Hong Jiang Cong Liu Yanshan Fang | 2019 | Cell Research2019，29，3： | 13 |
| 3 | Characterizing CO_2 fluxes for growing and non-growing seasons in a shrub ecosystem on the Qinghai-Tibet Plateau显示文摘To assess carbon budget for shrub ecosystems on the Qinghai-Tibet Plateau, CO2flux was measured with an open-path eddy covariance system for an alpine shrub ecosystem during growing and non-growing seasons. CO2 flux dynamics was distinct between the two seasons. During the growing season from May to September, the ecosystem exhibited net CO2uptake from 08:00 to 19:00 (Beijing Standard Time), but net CO2 emission from 19:00 to 08:00.Maximum CO2 uptake appeared around 12:00 with values of 0.71, 1.19, 1.46 and 0.67 g CO2m-2 h-1 for June, July, August and September, respectively. Diurnal fluctuation of CO2 flux showed higher correlation with photosynthetic photon flux density than temperature. The maximum net CO2 influx occurred in August with a value of 247 g CO2 m-2. The total CO2 uptake by the ecosystem was up to 583 g CO2 m-2 for the growing season. During the non-growing season from January to April and from October to December, CO2 flux showed small fluctuation with the largest net CO2 efflux of 0.30 g CO2 m-2 h-1 in April. The diurnal CO2 flux was close to zero during most time of the day, but showed a small net CO2 efflux from 11:00 to 18:00. Diurnal CO2 flux, is significantly correlated to diurnal temperature in the non-growing season. The maximum monthly net CO2 efflux appeared in April, with a value of 105 g CO2 m-2. The total net CO2 efflux for the whole non-growing season was 356 g CO2 m-2. | XU Shixiao, ZHAO Xinquan, FU Yuling, ZHAO Liang, LI Yingnian, CAO Guangmin, GU Song, WANG Qinxue & DU Mingyuan Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810001, China Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China Graduate School of the Chinese Academy of Sciences, Beijing 100136, China National Institute for Environmental Studies, Tsukuba 305-8569, Japan National Institute for Agro-Environmental Science, Tsukuba 305-8604, Japan | 2005 | Science China Earth Sciences2005，48，z1： | 12 |
| 4 | The vortex dynamics of a Ginzburg-Landau system under pinning effect显示文摘It is proved that the vortices of a Ginzburg-Landau system are attracted by impurities or inhomogeneities in the super-conducting materials. The strong H1-convergence for the system is also studied. | 简怀玉 徐兴旺 | 2003 | Science China Mathematics2003，46，4： | 11 |
| 5 | Unconventional Hamilton-type variational principles for nonlinear coupled thermoelastodynamics显示文摘According to the basic idea of classical yin-yang complementarity and modem dual-com plementarity, in a simple and unified new way proposed by Luo, the unconventional Hamilton-type vari ational principles for geometrically nonlinear coupled thermoelastodynamics can be established system atically. The new unconventional Hamilton-type variational principle can fully characterize the initia boundary-value problem of this dynamics. In this paper, an important integral relation is given, which can be considered as the expression of the generalized principle of virtual work for geometrically nonlin ear coupled thermodynamics. Based on this relation, it is possible not only to obtain the principle of vir tual work in geometrically nonlinear coupled thermodynamics, but also to derive systematically the complementary functionals for eight-field, six-field, four-field and two-field unconventional Hamilton type variational principles by the generalized Legendre transformations given in this paper. Further more, with this approach, the intrinsic relationship among various principles can be explained clearly. | 罗恩 黄伟江 邝君尚 罗志国 | 2002 | Science China Mathematics2002，45，6： | 9 |
| 6 | Stochastic modelling of soil moisture dynamics in a grassland of Qilian Mountain at point scale显示文摘Stochastic modeling of soil moisture dynamics is crucial to the quantitative understanding of plant responses to water stresses,hydrological control of nutrient cycling processes,water competition among plants,and some other ecological dynamics,and thus has become a hotspot in ecohydrology at present.In this paper,we based on the continuously monitored data of soil moisture during 2002―2005 and daily precipitation date of 1992―2006,and tried to make a probabilistic analysis of soil moisture dynamics at point scale in a grassland of Qilian Mountain by integrating the stochastic model improved by Laio and the Monte Carlo method.The results show that the inter-annual variations for the soil moisture patterns at different depths are very significant,and that the coefficient of variance(CV) of surface soil moisture(20 cm) is almost continually kept at about 0.23 whether in the rich or poor rainy years.Interestingly,it has been found that the maximal CV of soil moisture has not always appeared at the surface layer.Comparison of the analytically derived soil moisture probability density function(PDF) with the statistical distribution of the observed soil moisture data suggests that the stochastic model can reasonably describe and predict the soil moisture dynamics of the grassland in Qilian Mountain at point scale.By extracting the statistical information of the historical precipitation data in 1994―2006,and inputting them into the stochastic model,we analytically derived the long-term soil moisture PDF without considering the inter-annual climate fluctuations,and then numerically derived the one when considering the inter-annual fluctuation effects in combination with a Monte-Carlo procedure.It was found that,though the peak position of the probability density distribution significantly moved towards drought when considering the disturbance forces,and its width was narrowed,accordingly its peak value was increased,no significant bimodality was observed in the soil moisture dynamics under the given intensity of random fluctuation disturbance. | LIU Hu,ZHAO WenZhi HE ZhiBin & ZHANG LiJie Linze Inland River Basin Research Station,Chinese Ecosystem Research Network Laboratory of Watershed Hydrology and Ecol-ogy,Cold and Arid Regions Environmental and Engineering Research Institute,Chinese Academy of Sciences,Lanzhou 730000,China | 2007 | Science China Earth Sciences2007，50，12： | 7 |
| 7 | A preliminary study on vegetation-erosion dynamics and its applications显示文摘Vegetation-erosion dynamics is a new interdisciplinary science, studying the laws of evolution of watershed vegetation under the action of various ecological stresses. Introducing a qualitative expression of ecological stresses in this paper, the present authors establish the cou- pled differential equations for the vegetation-erosion process and derive a theoretical solution. The model is applied to the Anjiagou watershed on the Loess Pateau and the Xiaojiang water- shed and its sub-watersheds on the Yunnan Plateau. The calculated results agree well with the vegetation development processes. Abstracted from the differential equations the so-called vegetation-erosion chart is worked out, with which we can predict the development trend of vegetation under no human stresses. It is demonstrated that the erosion control is important for vegetation development and reforestation must be a long-term strategy. On the Yunnan Plateau with relatively high precipitation and temperature, vegetation can be greatly improved if erosion is controlled. On the dry and cold Loess Pateau suffering from high rate of soil erosion, however, vegetation can effectively control erosion but erosion reduction exhibits low effectiveness on vegetation development. Vegetation in the area is not stable and management is always needed to maintain the vegetation. | WANG Zhaoyin 1,2 , WANG Guangqian 1 , LI Changzhi 1 & WANG Feixin 1 1. Department of Hydraulic Engineering, Tsinghua University, Beijing 100084, China 2. International Research and Training Center on Erosion and Sedimentation, Beijing 100084, China | 2005 | Science China Earth Sciences2005，48，5： | 7 |
| 8 | Study on electromechanical coupling nonlinear vibration of flywheel energy storage system显示文摘The electromechanical coupling dynamics of the flywheel energy storage system (FESS) with a hybrid permanent magnetic-dynamic spiral groove bearing has been studied. The functions of the kinetic energy, the potential energys, the magnetic field energy in air gap of the flywheel motor and the energy dissipation of the whole system were obtained, and the differential equations set with electromagnetic parameters of FESS was established by applying the extended Lagrange-Maxwell equation. The four-order implicit Runge-Kutta formula to the equations was derived, and the nonlinear algebraic equations were solved by using the Gauss-Newton method. The analytical solution of an example shows that the upper damping coefficient, the lower damping coefficient and the residual magnetic induction of the rare earth permanent magnet play an important role in electromechanical resonance of the flywheel rotor system. There is a small change for the electromechanical coupling resonance frequency with the upper damping coefficient in-creasing, but the resonance amplitude decreases with the upper damping coefficient in-creasing. With the lower damping coefficient increasing, the resonance frequency in-creases, and the resonance amplitude decreases. With the residual magnetic induction of the permanent magnet increasing, the resonance frequency decreases, and the reso-nance amplitude increases. | JIANG Shuyun JU Lihua | 2006 | Science China(Technological Sciences)2006，49，1： | 6 |
| 9 | INCREASING RETURNS TO SCALE,DYNAMICS OF INDUSTRIAL STRUCTURE AND SIZE DISTRIBUTION OF FIRMS显示文摘A multi-agent model is presented to discuss the market dynamics and the size distribution of firms. The model emphasizes the effects of increasing returns to scale and gives the description of the born and death of adaptive producers. The evolution of market structure and its behavior under the technological shocks are investigated. Its dynamical results are in good agreement with some empirical “stylized facts” of industrial evolution. With the diversity of demand and adaptive growth strategies of firms, the firm size in the generalized model obeys the power-law distribution. Three factors mainly determine the competitive dynamics and the skewed size distributions of firms: 1. Self-reinforcing mechanism; 2. Adaptive firm growing strategies; 3. Demand diversity or widespread heterogeneity in the technological capabilities of firms. | Ying FAN Menghui LI Zengru DI | 2006 | Journal of Systems Science and Systems Engineering2006，15，1： | 5 |
| 10 | A dynamic model with substructures for contact-impact analysis of flexible multibody systems显示文摘Using a substructure synthesis method this paper studies the longitudinal compressive impact of a flexible bar with a rigid body. The crucial variable affecting the validity of the method is derived theoretically. By computational simulation tests, excellent agreement has been found be-tween the solution of this model and the exact solution when the variable is chosen suitably. Con-sidering both the computational efficiency and the accuracy of solutions obtained on the model in different engineering problems, several optimum values of the variable are suggested. | 郭安萍 洪嘉振 杨辉 | 2003 | Science China(Technological Sciences)2003，46，1： | 5 |
| 11 | The effect of decreasing alkalinity on microbial community dynamics in a sulfate-reducing bioreactor as analyzed by PCR-SSCP显示文摘PCR-single-strand conformation polymorphism (SSCP) and Southern blotting tech-niques were adopted to investigate microbial community dynamics in a sulfate-reducing bioreactor caused by decreasing influent alkalinity. Experimental results indicated that the sulfate-removal rate approached 87% in 25 d under the conditions of influent alkalinity of 4000 mg/L (as CaCO3) and sul-fate-loading rate of 4.8 g/(L·d), which indicated that the bioreactor started up successfully. The analy-sis of microbial community structure in this stage showed that Lactococcus sp., Anaerofilum sp. and Kluyvera sp. were dominant populations. It was found that when influent alkalinity reduced to 1000 mg/L, sulfate-removal rate decreased rapidly to 35% in 3 d. Then influent alkalinity was increased to 3000 mg/L, the sulfate-removal rate rose to 55%. Under these conditions, the populations of Dysgo-nomonas sp., Sporobacte sp., Obesumbacterium sp. and Clostridium sp. got to rich, which predomi-nated in the community together with Lactococcus sp., Anaerofilum sp. and Kluyvera sp. However, when the alkalinity was decreased to 1500 mg/L, the sulfate-removal rate rose to and kept stable at 70% and populations of Dysgonomonas sp., Sporobacter sp. and Obesumbacterium sp. died out, while some strains of Desulfovibrio sp. and Clostridium sp. increased in concentration. In order to determine the minimum alkalinity value that the system could tolerate, the influent alkalinity was de-creased from 1500 to 400 mg/L secondly. This resulted in the sulfate-removal rate, pH value and ef-fluent alkalinity dropping quickly. The amount of Petrotoga sp., Prevotella sp., Kluyvera sp. and Neisseria sp. reduced obviously. The result data from Southern blotting indicated that the amount of sulfate-reducing bacteria (SRBs) decreased with influent alkalinity dropping. Analysis of the microbial community structure and diversity showed that the SRBs populations were very abundant in the in-oculated activated sludge and the alkalinity decrease caused the reduction of the populations noted. Most of resident populations in the bioreactor were fermentative acidogenic bacteria (FABs), among which the phylum Firmicute was in the majority, but SRBs were very few. This community structure demonstrates the cooperation between SRBs and FABs, which sustains the system’s high sul-fate-removal and operation stability. | REN Nanqi1, ZHAO Yangguo1, WANG Aijie1, GAO Chongyang2, SHANG Huaixiang1, LIU Yiwei1 & WAN Chunli1 1. School of Environmental and Municipal Engineering, Harbin Institute of Technology, Harbin 150090, China 2. Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin 150040, China | 2006 | Science China(Life Sciences)2006，49，4： | 4 |
| 12 | Conformation and dynamics of polyoxyethylene lauryl ether (Brij-35) chains in aqueous micellar solution studied by 2D NOESY and 1H NMR relaxation显示文摘Spin-lattice relaxation time, spin-spin relaxation time and two-dimensional nuclear Overhauser enhancement spectroscopy (2D NOESY) experiments of polyoxyethylene lauryl ether (Brij-35) micelles in aqueous solutions at a concentration of 100 times the critical micellar concentration (cmc) give direct evidence that the hydrophilic polyoxyethylene chains, staying in the exterior of the micellar core, are coiled, bent and aligned around the micellar core with a certain number of water molecules included. This hydrophilic layer is in contact with the solvent, water, keeping the micellar solution stable. 1H NMR relaxation time measurements show that the first oxyethylene group next to the alkyl chain participates in the formation of the surface area of the micellar core. The motion of the hydrophilic polyoxyethylene chains is less restricted as compared with the hydrophobic alkyl chains. | 高红昌 方晓雯 毛诗珍 袁汉珍 赵濉 程功臻 俞稼镛 杜有如 | 2002 | Science China Chemistry2002，45，2： | 4 |
| 13 | MD simulation of the effect of contact area and tip radius on nanoindentation显示文摘Molecular dynamics simulations of nanoindentation are performed on monocrystal copper. A new contact atoms method is presented for calculating the contact area. Compared with conventional methods, this method can provide the contact area more accurately not only for sink-in but also for pile-up situation. The effect of tip radius on indentation is investigated too. The results indicate that the measured hardness of the material will become higher as the tip radius increases. | CHEN Shangda1,2 & KE Fujiu1,2 1. Department of Applied Physics, Beijing University of Aeronautics and Astronautics, Beijing 100083, China 2. State Key Laboratory of Non-linear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080, China Correspondence should be addressed to Chen Shangda (email: chensd@lnm.imech.ac.cn) Received August 27, 2003 | 2004 | Science China(Physics,Mechanics & Astronomy)2004，47，1： | 4 |
| 14 | Nonlinear Dynamics in a New Double Chain-Model of DNA显示文摘We investigate the mechanics ofa new double chain-model of DNA. The model consists of two long elastic homogeneous strands (or rods), which represent two polynucleotide chains of the DNA molecule, connected with each other by an elastic membrane (or some linear springs) representing the hydrogen bonds between the base pairs of the two chains. The nonlinear dynamical equations are derived and some solitary wave solutions are discussed. By the way,our model can be regarded as the mechanical model of cubic nonlinear Klein-Gordon equation and 4-field equation. | KONG De-Xing LOU Sen-Yue ZENG Jin | 2001 | Communications in Theoretical Physics2001，，12： | 4 |
| 15 | A general finite element model for numerical simulation of structure dynamics显示文摘A finite element model used to simulate the dynamics with continuum and discontinuum is presented. This new approach is conducted by constructing the general contact model. The conventional discrete element is treated as a standard finite element with one node in this new method. The one-node element has the same features as other finite elements, such as element stress and strain. Thus, a general finite element model that is consistent with the existed finite element model is set up. This new model is simple in mathematical concept and is straightforward to be combined into the existing standard finite element code. Numerical example demonstrates that this new approach is more effective to perform the dynamic process analysis in which the interactions among a large number of discrete bodies and continuum objects are included. | WANG Fujun1, LI Yaojun1, Han K.2 & Feng Y.T.2 1. College of Water Conservancy and Civil Engineering, China Agricultural University, Beijing 100083, China 2. Civil & Computational Engineering Centre, University of Wales Swansea, Swansea SA2 8PP, U.K. | 2006 | Science China(Physics,Mechanics & Astronomy)2006，49，4： | 3 |
| 16 | Nonlinear analysis of the alcoholic's EEG显示文摘The nonlinear analysis is used to study the EEGs of the alcoholic and the control. Three kinds of expansions are discussed in order to get a more proper delay and then Liangyue Cao algorithm is implemented efficiently. Totally, there are 40 subjects involved in this study and the average values and the sample variances of D2s are computed. The results show that the average value of D2s of the alcoholic is larger than that of the control when the same electrode was used, which means that the brain dynamics of the alcoholic is more complex than that of the control. On the other hand, for most of the electrodes, the sample variance of D2s of the alcoholic is larger than that of the control, suggesting that the brain dynamics of the alcoholic is less steady. | SHAO Chenxi SHEN Linfeng WANG Xufa and YIN Shijie(1. Department of Computer Science & Technology, University of Science & Technology of China, Hefei 230027, China 2. Department of Neurology, University of Medical Science of Anhui, Hefei 230022, China) | 2002 | Progress in Natural Science:Materials International2002，12，12： | 3 |
| 17 | Molecular Modeling of the Chain Structures of Polybenzoxazines显示文摘The structures and properties of benzoxazines were investigated by virtue of molecular modeling at a molecular level. By means of Cerius software(version 4.0) supplied by Molecular Simulations Inc., the molecular mechanics and the molecular dynamics were performed under a PCFF force field. Five kinds of the polymeric chains of benzoxazines were created by using polymer builder and energy minimization. The relaxation process was conducted with both energy minimization and molecular dynamics. | LIU Xin and GU Yi ** State Key Laboratory of Polymer Materials Engineering, Department of Polymer Materials Science and Engineering, Sichuan University, Chengdu 610065, P.R. China | 2002 | Chemical Research in Chinese Universities2002，18，3： | 3 |
| 18 | NUMERICAL SIMULATION OF ATOMIZATION GAS FIELDS IN VARIOUS ATOMIZING PROCESSES显示文摘A Computational Fluid Dynamics Software was used to calculate the atomizing gas fields generated by a self-designed atomizer and to analyze the effects of key atomizing variables such as gas pressure and protrusion length of delivery tube on the gas flow state at the tip of or inside the delivery tube. Increasing the length of delivery tube to a certain extent, the eddy flow region with positive pressure moves away from the tip of delivery tube, which is favorable to achieve the effective atomization of the melt. | F.Y. Cao, J.F. Sun, C.S. Cui, J. Shen and Q.C. LiNational Key Laboratory of Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001,ChinaManuscript received 10 December 2001 in revised form 31 January 2002 | 2002 | Acta Metallurgica Sinica(English Letters)2002，15，3： | 3 |
| 19 | CFD Model of Dense Gas-solid Systems in Jetting Fluidized Beds显示文摘A CFD code has been developed based on the conservation principles describing gas and solid flow in fluidized beds. This code is employed to simulate not only the spatiotemporal gas and solid phase velocities and voidage profiles in a two dimensional bed but also fluid dynamics in the jet region. The computational results show that gas flow direction is upward in the entire bed accompanied with random local circulations, whilst solid flow direction is upward at the center and downward near the wall. The radical reason of strong back mixing of solid particles and good transfer behavior between two phases is that the jet entrains solid particles. Numerical calculation indicates that gas velocity, solid velocity and pressure profile have a significant change when the voidage is 0 8. The simulated time averaged voidage profiles agree with the experimental results and simulated data reported by Gidaspow and Ettehadieh(1983). Therefore, CFD model can be regarded as a useful tool to study the jet characteristics in dense gas solid fluidized beds. | Kai Zhang ** , Jiyu Zhang and Biiang ZhangInstitute of Coal Chemistry, Chinese Academy of Sciences, P.O. Box 165, Taiyuan 030001, P. R.ChinaJohn YatesDepartment of Chemical Engineering, University College London, London, WC1E 7JE, UK | 2002 | Chemical Research in Chinese Universities2002，18，2： | 2 |
| 20 | 风力机组整机多体动力学建模与动态特性研究(英文)显示文摘选取某MW级风力发电机组为研究对象,设计了机组运动拓扑结构图,构建了风机整机的刚柔耦合多体动力学分析模型,并与气动力计算软件Aero Dyn和控制求解器通过接口力元实现联合仿真。模态分析计算得到了整机前6阶固有频率和模态振型,分析可知机组与关键转速区间激振频率不发生共振。动态仿真计算得到了3种不同工况下风机塔架迎风方向的位移、加速度动响应以及叶片三坐标方向的叶尖挠度,分析发现阵风期间塔架位移突然增大且瞬时波动剧烈;叶片的x方向叶尖挠度值最大,可能使叶片和塔架发生碰撞。 | 海几哲 孙文磊 周玉俊 | 2015 | 机床与液压2015，43，24： | 2 |
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