检索结果-南通市图书馆

Science China(Technological Sciences) 2005年第4期48卷 454-467页

作者： WANG jialu SHEN Pingping CHEN Yongzhong zhang Zubo jia xu TIAN Yuling Research Institute of Petroleum Exploration and Development Beijing 100083 China Research Institute of Petroleum Exploration and Development Beijing 100083 China Research Institute of Petroleum Exploration and Development Beijing 100083 China Research Institute of Petroleum Exploration and Development Beijing 100083 China Research Institute of Petroleum Exploration and Development Beijing 100083 China Research Institute of Petroleum Exploration and Development Beijing 100083 China

The fluid flow mechanism in porous media of enhanced oil recovery by Alkli/ Surfactant/Polymer (ASP) flooding is investigated by measuring production performance, pressure distribution and saturation distribution through installing differential pressure transducers and saturation measuring probes in a physical model of vertical heterogeneous reservoir. The fluid flow variation in porous media is the main reason of enhanced oil recovery of ASP flooding. The pressure field and saturation field are nonlinearly coupled together and the interaction between them results in the fluid flow variation in the reservoir. In a vertical heterogeneous reservoir, the ASP agents initially flow in the high permeability layers because the resistance in the high permeability layer is increased under the physical and chemical action of adsorption, retention and emulsion. ASP flooding displaces out not only the residual oil in the high permeability layer, but also the remaining oil in the low and the middle permeability layers by increasing swept volume and displacing efficiency.

关键词： ASP flooding, vertical heterogeneous reservoir, enhanced oil recovery, fluid flow mechanism in porous media.

Optimizing Seed Water Content:Relevance to Storage Stability and Molecular Mobility

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2010年第3期52卷 324-331页

作者： Ming zhang jia-Jin Zhuo xu Wang Sen Wu Xiao-Feng Wang Key Laboratory for Genetics and Breeding in Forest Trees and Ornamental Plants Ministry of Education Beijing Forestry University Beijing 100083 China

This research was conducted to determine the optimum moisture content （MC） that gave maximum longevity to seeds. Three species were used to represent seeds with different dry matter reserves, which gives them different sorption properties： maize （Zea mays L.）, elm （Ulmus pumila L.） and safflower （Carthamus tinctorius L.）. The seeds of elm, safflower, and maize embryos with MC ranging from 0.00- 0.15 g H2O/g dry weight （DW） were stored at 35℃ for different periods of time. The results showed that the optimum MC for seed and embryo storage varied between species （0.057 g H20/g DW for maize embryos, 0.045 g H20/g DW for elm, and 0.02 g H2O/g DW for safflower）. Drying below this optimum MC increased the aging rate and there were detrimental effects of drying. The relative humidity corresponding to optimum MC in embryos of maize, elms and safflower was about 15%, 12% and 7% respectively, according to the lipid composition of the embryos. The data provided confirmatory evidence that molecular mobility （△Azz） in elms, maize and safflower embryos was compatible with the optimum moisture content.

关键词： SEEDS MOISTURE CORN ELM SAFFLOWER MOLECULAR microbiology QUANTITATIVE research

Effects of size variation and spatial structure on plastic response of plant height to light competition

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2010年第12期55卷 1135-1141页

作者： CHEN ShuYan zhang jiaLin jia Peng xu Jin WANG Gang XIAO Sa Key Laboratory of Arid and Grassland Ecology of Ministry of Education School of Life Science Lanzhou University Lanzhou 730000 China

Plants only interact with neighbors over restricted distances,so local conditions are of great significance for *** this study,a spatially-explicit,individual-based model was constructed to explore the effects of size variation and spatial structure on adaptive plasticity of plant height in response to light *** the model a plant maintains its height at an optimal value in order to maximize its growth rate,and this optimal height increases with the increase of the intensity of light competition experienced by the individual *** the spatial pattern of the population is non-uniform or there is size variation among individual plants,the height growth curves of individuals different from each other vary due to the differences in the local light environment,and there is also variation in the allocation of photosynthate to height growth among the individual *** is no ESS height or height growth strategy on which all plants will *** results indicate that the plasticity of plants' height growth reactions to the light competition should be considered at the individual level and they argue strongly for the importance of the spatial pattern and neighborhood effects in generating the diversity of heights and height growth strategies in plant population.

关键词：空间结构光响应竞争塑料株高空间分布格局变异单株生长曲线

基于鲁棒L_2-L_∞/H_∞的车辆底盘集成控制

在线全文

学校读者我要写书评

暂无评论

吉林大学学报（工学版） 2016年第6期46卷 1757-1764页

作者：李静张家旭吉林大学汽车仿真与控制国家重点实验室长春130022 中国第一汽车股份有限公司技术中心长春130011

基于连续时间系统的鲁棒L2-L_∞及H_∞性能判据,推导出新的状态反馈的鲁棒L_2-L_∞/H_∞控制方法,并将其转化为具有较低保守性的线性矩阵不等式组的凸优化问题。利用该方法设计车辆底盘集成控制策略,协调控制主动前轮转向系统和主动悬... 详细信息

基于连续时间系统的鲁棒L2-L_∞及H_∞性能判据,推导出新的状态反馈的鲁棒L_2-L_∞/H_∞控制方法,并将其转化为具有较低保守性的线性矩阵不等式组的凸优化问题。利用该方法设计车辆底盘集成控制策略,协调控制主动前轮转向系统和主动悬架系统。采用Matlab/Simulink与Carsim联合仿真对典型工况进行验证,结果表明:所设计的车辆底盘集成L_2-L_∞/H_∞控制器在车辆极限条件下具有良好的协调控制性能,能够有效提高车辆的稳定性和防侧翻能力。

关键词：车辆工程鲁棒L2-L∞/H∞控制车辆底盘集成主动前轮转向主动悬架系统

在线全文

学校读者我要写书评

暂无评论

基于状态反馈的车辆底盘集成H_∞鲁棒控制

吉林大学学报（工学版） 2016年第3期46卷 685-691页

作者：李静张家旭吉林大学汽车仿真与控制国家重点实验室长春130022 中国第一汽车集团技术中心长春130011

采用二自由度车辆模型作为被控对象简化模型,提出了一种基于状态反馈的H_∞鲁棒控制方法的车辆底盘集成控制策略,协调控制主动前轮转向系统和直接横摆力矩控制系统。直接横摆力矩控制系统基于HSRI轮胎模型的逆运算和PI控制实现。通过J-t... 详细信息

采用二自由度车辆模型作为被控对象简化模型,提出了一种基于状态反馈的H_∞鲁棒控制方法的车辆底盘集成控制策略,协调控制主动前轮转向系统和直接横摆力矩控制系统。直接横摆力矩控制系统基于HSRI轮胎模型的逆运算和PI控制实现。通过J-turn工况和正弦延迟工况对H_∞鲁棒控制器进行仿真验证,结果表明,所设计的车辆底盘集成H_∞鲁棒控制器具有良好的控制效果,能够明显地改善车辆的操纵稳定性。

关键词：车辆工程底盘集成控制 H∞鲁棒控制主动前轮转向直接横摆力矩控制

基于混合优化方法的UniTire轮胎模型参数辨识

在线全文

学校读者我要写书评

暂无评论

吉林大学学报（工学版） 2017年第1期47卷 15-20页

作者：张家旭李静吉林大学汽车仿真与控制国家重点实验室长春130022 中国第一汽车集团技术中心长春130011

提出一种基于粒子群优化(PSO)算法和修正的Gauss-Newton算法的混合优化方法,对纯纵滑和纯侧偏工况下UniTire轮胎模型的特征参数进行辨识。为充分发挥两个算法的优点,首先,利用粒子群优化算法的全局区域的搜索优势辨识出UniTire轮胎模型... 详细信息

提出一种基于粒子群优化(PSO)算法和修正的Gauss-Newton算法的混合优化方法,对纯纵滑和纯侧偏工况下UniTire轮胎模型的特征参数进行辨识。为充分发挥两个算法的优点,首先,利用粒子群优化算法的全局区域的搜索优势辨识出UniTire轮胎模型的特征参数近似解,然后,利用修正的Gauss-Newton算法局部搜索优势在近似解邻近区域获得UniTire轮胎模型的特征参数的最优解。最后,对辨识结果进行残差分析,结果表明:用辨识数据参数化的UniTire轮胎模型具有较高的精度,可满足构建车辆底盘电控系统硬件在环仿真测试环境的需求。

关键词：车辆工程粒子群优化算法 Gauss-Newton算法 UniTire轮胎模型参数辨识

Clinical and pathological features of acute optic neuritis in Chinese patients

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2013年第9期126卷 1689-1692页

作者： zhang jia-ying SHEN xu-zhong SUN Li LU Zhao-zeng YE Wen Department of Ophthalmology Huashan Hospital Fudan University Shanghai 200040 China

Background The incentives and the factors that affect the onset and outcome of optic neuritis （ON） are not very clear. The aim of this study is to define and get a comprehensive understanding of the clinical profile of ON, and to identify the factors that were related to the prognosis of the patients. Methods Medical records of patients with diagnosis of ON at Huashan Hospital, Fudan University between March 2008 and June 2011 were reviewed. Clinical features, ophthalmologic and neurologic assessments, neuroimaging studies, laboratory examinations, visual recovery, and final outcome of the patients were evaluated by the authors. Results Records of 50 patients （32 females and 18 males）, aged 15-56 years, were reviewed, in which 22% patients had a previous onset of ON. Maximal visual deficit was severe in 72.5% （〈20/200）. Abnormal rates of hormone levels and rheumatoid indicators were found in 54.2% and 25.0%. ANA test returned positive in 40%, oligoclonal banding （OCB） was identified in 31.3%, and Serum neuromyelitis optica （NMO）-IgG studies were abnormal in 25% of the patients. Neuroimaging abnormalities associated with ON were documented in six patients. Three of the 50 patients have been diagnosed with multiple sclerosis, and two with NMO. Visual acuity was 20/20 or better in 26.1% and 20/100 or worse in 39.1% affected eyes at the last visit. Poor visual acuity at onset is the main factor that would affect the final outcome of vision （P 〈0.05）. Conclusions Vision defects of this group of patients were severe. Females had a higher incidence of ON than males. Hormone levels, rheumatoid indicators and immune parameters may be related to the onset of ON. The severe reduction of visual acuity at onset may be related to the poor outcome of vision in ON patients.

关键词： optic neuritis demyelinating diseases multiple sclerosis neuromyelitis optica

基于自适应快速终端滑模的车轮滑移率跟踪控制

在线全文

学校读者我要写书评

暂无评论

浙江大学学报（工学版） 2021年第1期55卷 169-176页

作者：李静王晨张家旭吉林大学汽车仿真与控制国家重点实验室吉林长春130011 中国第一汽车集团有限公司智能网联研发院吉林长春130011

针对汽车对连续、快速和稳定的车轮滑移率跟踪控制的需求,提出基于自适应快速终端滑模的车轮滑移率跟踪控制策略.基于Burckhardt轮胎模型建立车轮滑移率跟踪控制模型,将模型简化过程中的不确定性考虑成复合干扰项,将轮胎侧向力对纵向力... 详细信息

针对汽车对连续、快速和稳定的车轮滑移率跟踪控制的需求,提出基于自适应快速终端滑模的车轮滑移率跟踪控制策略.基于Burckhardt轮胎模型建立车轮滑移率跟踪控制模型,将模型简化过程中的不确定性考虑成复合干扰项,将轮胎侧向力对纵向力的影响考虑成未知参数.利用双曲正切函数和终端吸引因子设计改进的跟踪微分器,平滑车轮滑移率跟踪误差和估计车轮滑移率跟踪误差的一阶导数.以车轮滑移率跟踪控制模型和改进的跟踪微分器输出为基础,基于自适应快速终端滑模控制理论,设计对复合干扰项具有强鲁棒性的车轮滑移率跟踪控制律;基于投影算子理论设计自适应律来实时补偿未知参数,利用LaSalle不变性原理证明了闭环系统的渐近稳定性.利用车辆动力学软件仿真验证提出的控制律的可行性和有效性.结果表明,提出的车轮滑移率跟踪控制策略具有精度高和鲁棒性强的优点.

关键词：汽车动力学车轮滑移率跟踪控制自适应控制快速终端滑模控制

Deciphering the role of ultra-low-loaded rhodium in NiFe-MIL-53 for superior oxygen evolution reaction

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2025年第1期100卷 77-86页

作者： Jinzhi jia Jinhua zhang Kailu Guo Lanyue zhang Gening Du Hao You Junfeng Huang Mudong Tu Hua Li Yong Peng Wei Dou Cailing xu State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical Engineering School of Materials and Energy Lanzhou University College of Chemistry and Chemical Engineering Luoyang Normal University

Designing highly active and stable electrocatalysts of oxygen evolution reaction （OER） is one of the crucial *** this study,a novel OER electrocatalyst,NiFe-MIL-53 modified with ultra-low rhodium（Rh@NiFe-MIL-53）,is successfully prepared via the hydrothermal ***-situ Raman spectroscopy and electrochemical impedance spectroscopy reveal that the doped Rh accelerates the phase transformation of NiFe-MIL-53 and the in-situ formed Rh@NiFeOOH is the actual active *** importantly,the enhanced reversibility of electrochemical reconstruction between NiFeOOH and NiFe（OH）2after doping Rh is beneficial for improving the electrochemical stability of the catalyst.X-ray photoelectron spectroscopy spectra show the strong electronic interaction between single-atom Rh and Ni/Fe in Rh@***,theoretical calculations confirm that the integration of single-atom Rh into the NiFeOOH successfully reduces the band gap,regulates the d-band center （εd）,accelerates the charge transfer,and optimizes the adsorption behavior of oxygen-containing intermediates,thereby lowering the energy barrier of rate-determining ***,the optimized Rh@NiFe-MIL-53 exhibits excellent OER activity （240 mV） with a small Tafel slope of 48.2 mV dec-1and long-term durability (over1270 h at 10 m A cm-2and 110 h at 200 mA cm-2).This work presents a new perspective on designing highly efficient OER electrocatalysts.

关键词： NiFe-MIL-53 Rh Electrochemical reconstruction Catalytic mechanism Oxygen evolution reaction

猪脑突触体质膜(Ca^(2+)-Mg^(2+))-ATPase的分离纯化与性质

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

生物化学与生物物理进展 2001年第1期28卷 90-93页

作者：范晓轩张旭家中国科学院生物物理研究所

以猪脑为材料 ,经匀浆、差速离心、蔗糖密度梯度离心分离突触体 .低渗破膜得到突触体膜 .TritonX 10 0增溶后 ,经钙调蛋白亲和层析可得去脂的质膜Ca2 + ATPase .用大体积亲和柱和大体积低Ca2 +淋洗液淋洗 ,可得产率、纯度和活性均较高... 详细信息

以猪脑为材料 ,经匀浆、差速离心、蔗糖密度梯度离心分离突触体 .低渗破膜得到突触体膜 .TritonX 10 0增溶后 ,经钙调蛋白亲和层析可得去脂的质膜Ca2 + ATPase .用大体积亲和柱和大体积低Ca2 +淋洗液淋洗 ,可得产率、纯度和活性均较高的质膜Ca2 + ATPase .与大豆磷脂保温后 ,去脂的Ca2 + ATPase的水解活力可恢复达 3 32 μmol/ (mg·min) .SDS 聚丙烯酰胺凝胶电泳银染显示单一蛋白质带 ,分子质量约为 140ku ,纯度在90 %以上 .不同Ca2 +浓度明显影响酶的活力 .

关键词：质膜Ca^2+-ATPase 纯化钙调蛋白亲和层析性质