共查询到20条相似文献，搜索用时 125 毫秒
1.
The improvement of research on simulation of structural seismic responses based on neural networks(NN) is reviewed in this paper.Three key problems to simulate linear structures,selection of NN model,determination of NN structure and control of simulating precision,are discussed and the method to deal with the problems are suggested.Main problems of the research on simulating nonlinear structures under the action of earthquake ground motions based on NN are presented. 相似文献
2.
转cry1Aa基因抗虫棉整合结构解析及转化体特异性检测方法的建立 总被引：1，自引：1，他引：0
【目的】cry1Aa基因是2011年本实验室在我国棉花商品种子中发现的1种未经批准的转基因成分,本研究旨在通过整合结构解析,建立特异性检测方法,对市售棉种进行初测,明确该外源基因在我国棉种中的存在情况。【方法】通过Genome walking、长链PCR分离获得了转cry1Aa基因棉花转化体(定名为NN6转化体,简称NN6)的外源基因整合结构,同时基于插入位点基因组及外源DNA连接区,建立了NN6转化体特异性的定性聚合酶链式反应(Polymerase chain reaction,PCR)方法和实时荧光定量PCR方法。【结果】NN6整合结构主要包括cry1Aa、aad和Npt II基因,插入棉花基因组7号染色体37 169 450位,产生91 bp基因组缺失;所构建的定性PCR检测方法能特异、快速地对棉花单株和种子单粒中NN6转化体的纯/杂合状态进行鉴定,实时荧光定量PCR检测限为44拷贝,能满足国内外对转基因标识的需要;对含有cry1Aa基因的3个市售棉种进行检测,其纯合度分别为1.51%,5.21%和21.09%。【结论】本研究解析了NN6的整合结构,并建立特异性检测方法,为我国转基因棉花新品种选育及转基因安全管理提供技术手段。 相似文献
3.
Four techniques of dynamic mesh are Spring-based Smoothing, Dynamic Layering, Local Remeshing and the ALE method in the CFD transient simulation of engine. Based on those techniques, The authors analyze the improved measure of technique of dynamic mesh in the CFD transient analysis of the engine and propose the combined technique of dynamic mesh based on the finite volume method which is appropriate for. The CFD transient simulation of engine. At last, the 2D dynamic mesh method is applied to the typical pent-roof engine and the paper simulates the transient 3-D flow field at the tangent inlet of engine by applying the combined technique of dynamic mesh based on the finite volume method. The result of the simulation agrees well with experiment. 相似文献
4.
This paper presents the structure of a knowledge-based ECG automaticdiagnosis system and the key technologies applied in the system. Using database technology to store, the ECG knowledge-database is constituted of ECG knowledgeand a set of rules .The inference engine of the system simulates the real diagnosis of the experts and combines the forward reasoning with inexact reasoning. At the same time, complicated reasoning is avoided. Because the inference engine is independent of what is stored in the ECG knowledge-database, the system is suitable for expert system. 相似文献
5.
Firmness is an essential quality parameter of table grapes (Vitis vinifera) for consumers, with grape bunches that contains soft berries less preferred, resulting in a reduction in the market price. The softening of grape berries has been commonly associated with cell walls, especially the disassembly of pectic polysaccharides. However, the process of berry softening is not completely understood. To investigate the softening process of grape berries, we compared the Thompson Seedless variety, which suffers significant economic losses due to fruit softening, and NN107, a new variety with a significantly higher level of berry firmness. The composition of the cell wall during the berry development of these two grape varieties was compared. NN107 berries had a greater amount of calcium and uronic acids in the cell wall material than Thompson Seedless grapes, suggesting a special role for calcium bridge formation in NN107. Additionally, polyacrylamide carbohydrate electrophoresis (PACE) analysis suggested differences between these varieties in pectin structure. Thompson Seedless grapes showed increased pectolyase hydrolysable site dynamics in the cell wall material and higher polygalacturonase activity than NN107. Immunohistochemistry focusing on the pectin structure confirmed the roles of both calcium bridge formation and cell wall integrity as they relate to a firmer grape berry phenotype. 相似文献
6.
An original thermodynamic idea for Power MEMS, which is called as quasi gas power cycle, is proposed to further intensify energy density and simplify structure of Power MEMS. Because gas supply with preset high pressure is set up in the Power MEMS engine of quasi gas power cycle, it is convenient for the Power MEMS engine to employ externally pressurized gas bearings to improve the performance of its bearings. Therefore mal design philosophy and structural type of the hyrostatic journal bearing as well as the hyrostatic thrust bearing in the Power MEMS engine are investigated, considering the limiting factor on meso scale. Then the structural and operational parameters are analyzed, and the optimal designs of typical externally pressurized gas bearings are put forward. Moreover the feasibility of the externally pressurized gas bearings applied to the Power MEMS engine is further verified by the calculation of load-carrying capacity of the hyrostatic gas bearings. 相似文献
7.
In order to accurately reflect the dynamic behavior and realize the whole optimal control of the thermal process, a novel modeling method of the RBF NN (Radial Basis Function Neural Networks) model is proposed to build nonlinear model. This method is based on entropy clustering and competitive learning algorithm, combined with nonlinear autoregressive moving average (NARMA) model to identify the RBF NN stucture, and the power vector is gotten by the least square algorithm. Two simulation experiments show that the proposed method of the identification based on NARMA model and RBF NN can accurately describe the non linearity of the process and has less hidden nodes. 相似文献
8.
9.
烟草SKP1基因cDNA的克隆分析及原核表达 总被引：1，自引：0，他引：1
应用DDRT-PCR法获得可被壳寡糖诱导的枯斑三生烟SKP1基因cDNA的3’端序列,通过5’ RACE扩增该基因cDNA的5’ 端,进而扩增此基因cDNA的全长,通过同源性比较分析,与本塞姆氏烟草的SKP1基因同源性达81%,其cDNA全长653 bp(GenBank登录号：AY702087),其中编码区位于73~540 bp,编码一条155个氨基酸的多肽。经预测该多肽的分子量为17 527.78 Da,等电点为4.57,定位于细胞质,功能结构域分析结果显示在4~105位氨基酸有一明显的Skp1结构域,其E值为1.25e-52,因此推断该基因为枯斑三生烟的SKP1基因。将该基因编码区亚克隆到原核表达载体pET23b(+)上,转化大肠杆菌BL21(DE3),表达出与预测分子量一致的蛋白。为进一步研究该基因的功能奠定了基础。 相似文献
10.
11.
As a single system of evaluation, both neural network (NN) and traditional expert system (ES) have many limitations. Developing evaluation system integrating NN with ES is an available way to offset their weakness. With black-box module, a new frame of evaluation system is developed in relative independent method. Then, a way of programming and realizing evaluation system, which is more close to human thinking, is put forward. 相似文献
12.
BP(Back Propagation) Neural networks is in the presence of the local optimization in the Neural networks training.The algorithm have slow convergence and the local convergence problem which impact the neural networks work performance.In order to cover these shortcomings and solves the size's hugeness and the low efficiency of the net problem in the traditional NN designing,the action principles of BP-Neural network's structure are analyzed,and a new method is formed which is confirmed from the Enhance genetic algorithms(EGA).The method can identify network configuration and network training methods.By adopting the number coding,self-adaptable multi-point variations operation,this method can effectively reduce the network size and the network convergence time,increase the network training speed.Tomatoes disease diagnosis examples illustrate the feasibility of this approach. 相似文献
13.
CVT刚性联接发动机曲轴轴系结构的扭振分析 总被引：1，自引：0，他引：1
因非道路车辆的特殊结构和成本限制，提出四缸柴油发动机中采用CVT刚性联接曲轴轴系结构。阐述了该新型结构的特征和工作原理，建立了四缸柴油发动机离合式曲轴计算模型和CVT刚性联接曲轴计算模型。通过曲轴前端实验，证明了所建模型和模型参数确定方法的正确性。求解所有计算模型，并对结果进行对比分析。结果表明，CVT刚性联接使曲轴轴系振动波动加大，减振器耗散能增加，各阶共振峰值对应转速低减。对曲轴各拐剪切应力幅度的影响不大，但有高转速工况降低而中低转速剪切应力幅值增加的普遍趋势，CVT端的扭振振幅和剪切应力较大些。综合研究得出结论：非道路车辆低速四缸柴油发动机可以采纳CVT刚性联接曲轴轴系结构。 相似文献
14.
水分胁迫对贪青水稻籽粒充实及其淀粉合成关键酶活性的影响 总被引：8，自引：1，他引：8
以两个灌浆速率差异较大的杂交稻组合(汕优63，Pc311/早献党)为材料，设置出穗后高氮(HN)和正常氮(NN)两个水平，以正常灌水为对照(WW)，研究适度水分胁迫(WS)对水稻籽粒灌浆速率与籽粒中淀粉合成关键酶活性的影响。结果表明， HN导致水稻贪青迟熟，主要表现为淀粉积累速率和积累量显著下降，造成粒重和产量降低。适度水分胁迫处理能有效改善贪青稻株的籽粒充实状况。施高氮导致水稻籽粒中蔗糖合成酶(SuSy)、腺苷二磷酸葡萄糖焦磷酸化酶(ADP-Gppase)、颗粒结合淀粉合成酶(GBSS)、可溶性淀粉合成酶(SSS)和淀粉分支酶(SBE)活性降低，是贪青稻株籽粒淀粉积累速率下降和充实不良的内在生理原因。适度水分胁迫处理能诱导籽粒中SuSy、ADP-Gppase、SSS和SBE活性上升，进而增加籽粒淀粉积累和粒重。而正常施氮下，水分胁迫导致稻株籽粒灌浆后期同化物供应不足和淀粉合成代谢酶活性下降过快，是其籽粒淀粉积累总量减少、粒重降低的主要原因。 相似文献
15.
With unique configuration characteristic,dual-clutch transmission(DCT)overcomes the shortcoming of power interruption when shifting in traditional AMT,which results in good power performance,fuel economy and driving comfort,and recently it becomes a new development trend in the field of transmission.Basing on the analysis of starting control principle of DCT,control principle and method that both the dual clutch engaged in the starting process simultaneously with engine constant speed are proposed.And the starting characteristic of the dry dual-clutch transmission is simulated and analyzed,providing theory foundation for the development and research of the dual-clutch transmission. 相似文献
16.
A multi rigid body dynamic model of an all terrain vehicle (ATV) is established in MSC.ADAMS. The model takes into consideration the body, suspension, frame and the steering system. According to the method of superposition of harmonic wave, a Grade B road file is created in ADAMS for the riding comfort test. The engine excitation is analyzed. The infliction for engine excitation to ADAMS is achieved. The ATV ride comfort simulation is carried out with the excitation of the engine, and the seat vibration is evaluated using an evaluation method programmed via MATLAB. It has laid a good foundation for further analysis. 相似文献
17.
DENG Guo-hong~ 《保鲜与加工》2004,(10):8-13
A method of diesel engine fuel system fault diagnosis based on wavelet transform and fuzzy C-means clustering is presented. Five characteristic parameters of reflecting fault state are distilled with wavelet transform of pressure wave of high-pressure oil pipe of diesel. The theory and generic approach of fuzzy C-means clustering algorithm (FCM) is given, and the validity of evaluating fuzzy clustering making use of partition coefficient, partition entropy and parting coefficient is pointed out. Identification of fault mode can be completed utilizing standard fault character modes established by FCM algorithm, and calculating and comparing the similarity degree between this standard mode and sample. The arithmetic is applied to all kinds of typical faults diagnose in the diesel engine fuel system. Measuring results indicate that the precision of fault diagnosis is increased with the analysis of wavelet and FCM. 相似文献
18.
《保鲜与加工》2003,(11):6
This paper briefly introduces the structure and main function of a mild hybrid system based on ISA. The components of the whole powertrain system include ISA,engine and battery. Transmission is choosed according to its typical configuration and functions. In addition,the specific parameters of power and torque of ISA,engine power,the number and capacity of battery,the gear ratio of gearbox are determined according to the required performance and fuel economy. In order to achieve the design target, the Genichi Taguchi method is used to optimize the gear ratio. At the same tine, the simulation of ISA mild hybrid vehicle is carried out and compared with conventional vehicle by using the ADVISOR software. 相似文献
19.
Marília Caixeta Franco Sérvio Tulio Cassini Valter Rodrigues Oliveira Clibas Vieira Siu Mui Tsai Cosme Damiao Cruz 《Euphytica》2001,118(3):265-270
Ten F1's obtained from crosses among five common bean genotypes of Andean (WAF 15, Mineiro Precoce and Batatinha) and Middle American
(BAT 304 and Ouro) gene pools were assessed for their combining abilities for root nodulation with Rhizobium tropici strain CIAT 899. The plants were grown under controlled conditions and evaluated for number of nodules per plant (NN), nodule
dry weight (NDW), mean nodule weight (MNW) and plant fresh weight (PFW). The subdivision of the treatment effects on the general
(GCA) and specific combining effects (SCA) were performed according to Griffing's diallel analysis method 2, model 1. The
analyses of variance and estimates of quadratic components showed that non-additive gene effects were more important in the
expression of NN and PFW, whereas additive gene effect was predominant for NDW and MNW. A close association was observed between
high number of nodules and GCA. Generally, crosses involving parents of different gene pools yielded hybrids with high positive
estimates of SCA for all assessed traits. The genotypes of Andean origin WAF 15 and Mineiro Precoce are the most promising
parents for breeding programs to increase NN and NDW in common beans.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
20.
With the development of high-speed and high-power, the motorcycle vibration from engine become one of the major factors affecting the performances of motorcycle. Elastic suspension structure is adopted between the engine and frame for the vibration during the process of designing a certain type of motorcycle with 200 cc engine in some enterprise.Through optimization of the suspension system performance parameters, inherent frequency of suspension system keeping away from the activated frequency of engine in common use is essential. Isolation performance is improved and the vibration is solved. As a result, the comfort is improved. 相似文献