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Search Results: 1 - 10 of 13822 matches for " 白骅 "
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运输通道货运量分担率的目标规划模型
 ,朱 彤
长安大学学报(自然科学版) , 2014,
Abstract:
公路景观规划设计的螺旋模型架构
 ,贾诗炜,吴 刚
长安大学学报(自然科学版) , 2013,
Abstract:
基于集对分析的区域农村公路建设发展阶段性评价
Evaluate of regional rural road construction and development of static phase based on set pair analysis

,王建军,许鹤
- , 2018,
Abstract: 为了合理有效评价区域农村公路建设的发展阶段实际状况,针对性的指出薄弱环节和改进方向,提出了一种基于集对分析的区域农村公路建设发展阶段评价方法。在总结相关研究的基础上,结合农村公路特点,运用目标分解的逻辑方法,从农村公路建设率、养护与安全水平、运营水平、管理强度4个方面,建立区域农村公路建设发展的分阶段指标体系。综合运用层次分析法(AHP)和嫡技术得出各评价指标权重。通过计算各指标的联系程度,采用均衡原理判断区域农村公路建设发展的阶段性结果,以福建省农村公路的发展为例,合理确定该区域农村公路发展的整体水平。研究结果表明:福建省农村公路发展评价结果为优良处于较高水平,并找出了农村公路建设发展过程中的薄弱环节;用集对分析模型(SPAM)对区域农村公路建设发展进行评价的结果与实际分析的结果基本接近,说明该方法的客观合理性。该方法不仅能为下一阶段农村公路政策制定提供依据,还能为此类评价提供一种新方法。
In order to realistically and effectively evaluate regional rural road construction and static phase development, and point out weaknesses and direction of improvement, a comprehensive evaluation method was proposed based on set pair analysis. On the basis of summary research results, a target decomposition method was used to establish a phased index system for regional rural highway construction development from four aspects: construction rate, maintenance integrity, operational level, and management involvement. The analytical hierarchy process (AHP) and entropy techniques were integrated to determine the weight of each index. By calculating the contact and degree of each index, the principle of sharing was used to judge regional rural road construction and development evaluation results to rationally determine the overall level of rural highway development in the region.The evaluation results show that rural highway development in the Fujian Province is at a high level, and the weak links in the process of rural highway construction are exposed.Evaluation results of regional rural highway construction development with set pair analysis method (SPAM) are similar to that of actual analysis, indicating that the method is objective and realistic. This method provides a basis for the next stage of rural highway policy formulation and its evaluation. 4 tabs, 1 fig, 19 refs.?
基于Peters-ONERA模型的失速颤振特性研究
Investigation of Stall Flutter Based on Peters-ONERA Aerodynamic Model

梁佳,俊强,李国俊
- , 2018,
Abstract: 采用Peters模型模拟线性气动力,ONERA失速模型模拟由于动态失速引起的非线性气动力,通过耦合结构运动方程,建立了状态空间(state-space)形式的气动弹性控制方程。采用欧拉预估-校正方法对该方程进行时域推进求解,采用特征根轨迹分析技术在频域内对气动弹性系统进行稳定性分析。基于Peters-ONERA气动力模型对动态失速现象进行模拟,结果表明该气动力模型可以准确地捕捉动态失速气动力的主要特征。采用该气动弹性模型对亚松弛迭代(under relaxation iteration)方法在静气动弹性求解稳定性中的影响进行了研究,研究结果表明,亚松弛迭代可以增强静气弹求解的稳定性。分别采用频域和时域方法对失速颤振中的颤振临界特性和分岔(bifurcation)现象进行了研究,并分析了初始扰动对系统响应的影响。研究发现:①在大攻角下,非线性气动力模态与结构模态的耦合可能导致结构模态的失稳,从而诱发系统的单自由度颤振;②初始攻角的改变会显著影响系统的分岔特性;③在不同的扰动范围内,气动弹性系统对扰动的敏感度不同,扰动增强可能会使系统原先稳定的状态被激发为极限环振荡(limit cycle oscillation,LCO)状态。
The Peters model is used to simulate the linear aerodynamic force and ONERA stall model is used to simulate the nonlinear aerodynamic force. The state-space equation of the aeroelastic system is established by coupling the structural equation. In order to solve problems, Euler predictor corrector method is used in the time domain and eigenvalue analysis method is used in the frequency domain. The case of dynamic stall is simulated based on Peters-ONERA model and the results imply that the validity of the aerodynamic model. The effect of under relaxation iteration on the stability of static aeroelastic solution is studied. It is found that under relaxation iteration can improve the static aeroelastic solution stability. Then based on frequency and time domain methods, flutter critical characteristic and bifurcation phenomenon are studied. It is found that:(1) Under large angle of attack, the coupling between nonlinear aerodynamic modal and structure modal could induce the instability of the structure modal and single degree of freedom flutter. (2) Under different angles of attack, bifurcation characteristic of aeroelastic system is far different. (3) The sensitivity to the disturbance of the system is different in different ranges. When the disturbance increases, the aeroelastic system will change from stable state to limit cycle oscillation
头孢菌素C发酵过程代谢特性
冀志霞,储炬,庄英萍,张嗣良,罗家立,
华东理工大学学报 , 2006,
Abstract: 考察了头孢菌素C的发酵过程特征,对发酵过程的重要生理参数DO、CER、OUR、RQ等进行了在线检测和相关分析,并分析了比生长速率和比产物生成速率的变化规律。在发酵过程中OUR、CER最高分别达到了90.2mol/(m3.h)和69.8mol/(m3.h),表明头孢菌素C发酵代谢强度很大,对氧的需求量也非常大。比产物生成速率在发酵60~100h最高达到2.15U/(h.g)(细胞干重)。同时分析了头孢菌素C发酵过程中甲硫氨酸代谢规律,表明维持培养基中一定浓度的甲硫氨酸对头孢菌素C的合成有促进作用。通过对三级发酵和四级发酵的比较,表明在现有的设备和工艺条件下,三级发酵生产头孢菌素C要优于四级发酵,同时通过控制发酵前期菌丝浓度可获得最大产素水平。
fsh通过激活erk1/2调节仔猪睾丸支持细胞gdnf的表达
孙燕,王鲜忠,吴建云,汝岚,张家
牲畜兽医学报 , 2008,
Abstract: ?以体外培养的仔猪睾丸支持细胞为研究对象,研究了fsh对gdnf蛋白的调节及其信号传导机制。结果显示:(1)外源性fsh以浓度和时间依赖性促进gdnf蛋白表达:fsh浓度为50ng/ml、作用1h时,gdnf水平达到最高;(2)用fsh(50ng/ml)或dbcamp(100μmol/l)处理支持细胞,可迅速激活mek激酶,随fsh刺激时间的延长,erk1/2活性逐渐升高(0~2h);(3)mek1/2的抑制剂u0126可显著抑制fsh对gdnf的激活作用。结果表明,fsh在诱导gdnf蛋白表达的过程中,通过camppkaerk1/2级联通路,促进gdnf基因的表达。
Genome labeling of the Streptomyces strain HS007
链霉菌工业菌种HS007的基因组标记

Jun Huang,Haibin Wang,Jiali Luo,Hua Bai,
黄隽
,王海彬,罗家立,

微生物学报 , 2008,
Abstract: By construction of small fragments genome bank, several different fragments from chromosomal DNA of streptomyces production strain HS007 were cloned into cloning vector pSP-SIM. According to the sequencing results, five of them, which were 3- to 7- kb in size with single restriction sites in the middle, were cut down and re-cloned into bacteria-streptomyces shuttle vector pHJL400. Subsequently, the marker cassette, composed of special labeling sequence, oriT, 2 FLP recognition target sites and apramycin resistance gene, was inserted into the single restriction sites to create recombinant plasmids pHJL02AFOH, pHJL07AFOH, pHJL08AFOH, pHJL10AFOH and pHJL 12AFOH. These recombinant plasmids were then transformed into target production strain HS007 by conjugal transfer method, and corresponding marked mutants named 02-72, 07-44, 08-02, 10-81 and 12-58 were screened. Two of these mutants, 02-72 and 12-58, did not show changes in fermentation ability, whereas the others lost partially or completely fermentation ability. The apramycin resistance gene and oriT, flanked by two FLP recognition target sites, were then removed by FLP-mediated deletion from recombinant plasmid pSP02AFOH to give pSP02F, whereas the special labeling sequence was still reserved in pSP02F because of being located out of the two FLP recognition target sites. Finally, replacement plasmid pGH02FH was constructed by replacing the vector part of pSP02F with bacteria-streptomyces shuttle vector pGHll2 and transformed into mutant 02-72. By selecting apramycin sensitive colonies, marked mutant 02-72-36, whose chromosome was inserted by special labeling sequence without apramycin resistance gene, was screened. Fermentation confirmed that its production ability was not reduced. Such genome labeling technique might be used in other strains of streptomyces to protect the property marks.
乙烯直接氧化制取乙二醇酯的研究 Ⅱ.反应—萃取过程的探讨
陆广中,汪仁,全凤,黎焯堃,马名,祁和干
华东理工大学学报 , 1984,
Abstract: 为节约石油资源,提高乙烯加工效率,世界各国近十年来都纷纷对乙二醇合成方法予以探讨。其中受到重视的方法之一是乙烯直接制备乙二醇酯法,我们对此法进行了研究。由于直接法回收催化剂和溶剂循环要求大量能耗,本文主要是探索新的反应—萃取系统,从而使能耗降低。
液晶显示器的维护与保养

中国图象图形学报 , 2002,
Abstract:
经济型LCD大比拼

中国图象图形学报 , 2002,
Abstract:
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