Dynamic signatures method for analysis of vehicle bridge resonance

The dynamic behavior of railway bridges (dynamic deflection and acceleration) is one of the running safety control indices for high speed trains. Therefore, the dynamic behavior of railway bridges is studied based on the concept of the dynamic signatures of the train and the bridge. By simplifying the train excitation as a series of moving concentrated forces, the mathematical expressions of the dynamic signatures of the train are obtained through theoretical derivations, and then a method is presented for calculating the resonance speed of trains and the maximum vertical acceleration of the bridge. With this method, the dynamic responses of the simple supported bridge can be calculated quickly. The feasibility of this method is validated through some examples, in which the resonance mechanism of train bridge system and the influencing factors are investigated. In addition, the effect of high frequency components to the bridge acceleration is also analyzed.     

智能视频分析的车辆异常行为检测方法

为验证公司自主研发的呋喃它酮代谢物化学发光微粒子检测试剂盒的检测效果,用化学发光微粒子免疫法和高效液相色谱串联质谱法对猪肉、鸡肉、鱼肉、虾4个样品中呋喃它酮代谢物残留量进行检测,比对两种方法试验结果间的差异。结果表明,使用直接竞争CLIA试剂盒检测动物性食品中呋喃它酮代谢物残留量,其特异性强,灵敏度较高,在猪肉、鸡肉、鱼肉、虾样品中0.2、0.4、0.8μg/kg 3个水平的加标回收率均在94.0%~101.0%之间,变异系数均小于15%,最低检测限分别为86.24、84.09、84.51、88.12 ng/kg;此方法与高效液相色谱串联质谱法检测实际样品的阴、阳性判断结果一致,其结果稳定、可靠,可满足现场快速检测动物组织中呋喃它酮代谢物残留的要求。     

Sensitivity analysis of a motorcycle frame using the Monte Carlo method

Sensitivity analysis of motorcycle frames is useful for improving the design success rate. Based on sensitivity analysis theory and using the Monte Carlo and numerical simulation methods, a new 250 type integral motorcycle model was built and dynamic sensitivity analysis conducted. Sensitive design parameters that have great influence on frame vibration were discovered. By modifying the values of sensitive design parameters, the vibration of some measuring points was reduced. This reduction shows that the sensitivity analysis method is reliable and practical, and it can be used in sensitivity analyses of other complicated structures.     

Simulation and analysis of all terrain vehicle ride comfort

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.     

Dynamic characteristic analysis of an all terrain vehicle body

The body is a key part of all terrain vehicles (ATV). Its dynamic characteristics greatly effect the vibration of the ATV assembly. Simulation and experimental methods are combined to analyze ATV body vibration characteristics. A computer aided design(CAD) model is built using UG4.0. A finite element method(FEM) model of an ATV body and a body with an engine are created using Hypermesh. The FEM model is imported to Msc.Nastran to calculate the free mode. The simulation model is verified by the experimental modal result. The results indicate that after the frame with engine, the first bending mode increases due to the engine increasing the body stiffness, while the first torsion mode decreases due to the engine mass. The effects on the dynamic response of the road and engine excitation are analyzed respectively. Vibration characteristic improvement methods and suggestions regarding the body are provided.     

Quantitative analysis of damage extent of transmission tower by using strain energy method

In order to solve the structural damage identification problem of transmission tower, a two-step identification method based on change rate and dissipation rate of modal strain energy is proposed. The damage location is identified by the change rate of modal strain energy method. Then, the modal strain energy dissipation rate theory is analyzed further by using the element stiffness matrix after injury. As a result, a more accurate damage quantification equation method is introduced. This method requires only several modals of vibration. The numerical simulation results show that this two-step method can find the damage location and damage degree of transmission towers effectively.     

The optical isolation method of suppressing electromagnetic interference of automotive ignition system

Electromagnetic radiation, which is caused by the engine ignition system, is the most powerful electromagnetic interference (EMI) source in the vehicles, as well as the main reason of most electronic control unit (ECU) malfunction. In order to reduce interference from ignition noise on ECU, we use optical isolation technology to isolate electrical connections between the interference source and the control circuit. The formation mechanism of the ignition system EMI is analyzed. The possibility of suppressing ignition system EMI with optical isolation technology is discussed. Then, as a result we design an experimental platform of suppressing ignition system EMI. The experimental results show that the effect of suppressing ignition noise, in 20~100 MHz frequency band, is obvious after applying optical isolation circuit. It can address the issue of automotive EMC.     

Simulation analysis on braking system of hybrid vehicle with ISG

A hydraulic braking system of the hybrid vehicle is designed based on braking force distribution and brake pressure coordination control strategy of integrated startor and generator(ISG) hybrid electric vehicle(HEV). Simulation model of hydraulic braking system has been established using AMESim software platform. Dynamic performance simulation and analysis to the key components and systems are performed. The results verify the correctness and feasibility of system program and provide evidence for designing and optimizing of HEV braking system.     

The study on EMI principle and suppression method of vehicle ignition system

Vehicle ignition system is the main electromagnetic interference source. Electromagnetic radiation produced by ignition system will produce the interference to electromagnetic environment around. It is necessary to study the electromagnetic interference (EMI) principle, noise paths and suppression method. We analyze the electromagnetic interference principle of ignition system, and harness trouble-shooting related to electromagnetic interference is also tested. Results show that the spark discharge between spark plug electrodes is the main interference source in ignition system. Then, the paths of conducted interference and the reason of radiated emission are discussed in detail. Finally, two kinds of power supply cord EMI filters are designed and implemented on the basis of analysis results. Experimental results indicate that the filter can reduce the noise of power-wire in broadband range. Simultaneously, the radiation emission performance from power wire is also reduced observably. The proposed mixing filter has been demonstrated in this paper to perform satisfactorily with excellent effectiveness in suppression of conducted EMI from 10 MHz to 110 MHz, and the object car can also pass the EMC standard tests.     

Dynamic scheduling method of vehicle air-conditioning assembly shop based on feedback control

By analyzing the inherent uncertainties, discrete uncertainties and external environmental uncertainties, a dual-feedback control strategy and the dynamic scheduling method are proposed to solve the dynamic scheduling problem of vehicle air-conditioning assembly shop under uncertainty. Considering the reentrant constraint, equipment capacity constraint, and time discrete constraint etc., the multi-objective scheduling model of vehicle air-conditioning assembly shop is set up,taken the earliness/tardiness, process time, production cost and quality loss as optimization objectives. According to the characteristic of the model, sectional chromosome encoding, crossover operator and mutation operator are designed to prevent the generation of illegal solutions and improve efficiency of the algorithm. An example is given to prove the feasibility and validity of the approach.     

Analysis and experiment for reliability of power module driving circuit in renewable energy conversion system

Reducing the driving resistance for the present push-pull driving circuit for power module will make the time shorter,but this process will result in the increase of current and voltage thermal stress. Therefore,a novel driving method based on dSPACE is introduced and validated on the basis of analyzing the failure mechanism and thermal model of power module. The ascending theory of case-temperature is investigated and then an exponential curve is achieved for power module. Experiments prove that the method has a good driving and protective performance,and it effectively reduces harmonics of output current and voltage in the new energy conversion system,and enhances the voltage utilization rate and waveforms quality. Thus the reliability of power module is greatly improved.     

天然气汽车改装中CNG喷射器喷嘴孔径的确定

在压缩天然气汽车(CNGV)的改装过程中,CNG喷射器喷嘴孔径这个工艺参数,极为关键却又难以把握。为了提高安装作业的效率及精度,探究出一种能辅助安装者更快更准地确定所需孔径的方法,提出了以模糊模式识别原理的算法,根据待改装车辆的发动机功率、行驶总里程和当前火花塞使用中的行驶里程这3个指标,对喷嘴孔径的尺寸进行识别,以实现在CNG系统安装前对孔径进行确定。在MATLAB中对该算法进行验证时,发现采用随机性更好的分组抽样且对算法的数据运算过程进一步匹配修正后,孔径的识别精准性显著提高。经过与此前的实际安装记录数据的核对,最终证实了该算法的可行性及准确性。     

The analysis of China wind power industry

The development course of China wind power industry is reviewed by six stages. National policies on wind power industry are elaborated from the aspects of laws & regulations, planning, finance & taxation and electrovalence policy. And these policies have played an important supporting and regulating role in the development of wind power industry. The development status of China wind power industry is analyzed based on wind turbine installed capacity, wind power output and their growth rate. It is explained that national wind turbine manufacturers have kept developing and become strong by the data of new global installed capacity share of mainland wind turbine manufacturers in 2013 and the new global market share of 8 domestic enterprises among the world top 15 wind turbine manufacturers. But there are still 5 key problems which influence the development of national wind turbine need to be solved, including lack of top-level design, abandon and restriction wind power seriously, lack of R&D abilities, some of the key parts relying on imports and wind turbine facing a quality guarantee dilemma. Taking Sinovel Wind Group Co. Ltd. and Xinjiang Goldwind Sci & Tech Co. Ltd., the two leading companies as an example, their performance is analyzed and it’s pointed out that the wind industry must keep vigilant after the overspeed development. The enterprises should try to avoid neglecting cultivating their inner core competitive ability, including technology advancements and products reliability. Occupying the market with low price competition and expanding blindly is also not desirable. At last, the development prospects of our country’s wind power industry are analyzed and three proposals are put forward.     

A method of power measurement under nonsinusoidal periodic signals

In power system,traditional method of nonsinusoidal power measurement is not feasible for containing non integer harmonics condition. A method of power measurement based on Prony algorithm is presented. At first, identify all modes of integer and non interger harmonics from voltage and current signals, using Prony method. Futher more, calculate active and reactive power in each harmonics frequency, using the modes of harmonics. Based on the defination of IEEE active power, a expression of Budeanu power is given in non integer harmonics condition. At last, active and reactive power of energy gird are calculated. The results of simulation prove that this method is feasibility. The method of power measurement based on Prony algorithm has high precision, especially for non integer harmonics condition.     

A practical method for apple cultivar identification and parent-offspring analysis using simple sequence repeat markers

Differentiation of cultivars with simple sequence repeat (SSR) markers is a very useful technique for the true-to-type characterization of cultivars and clarification of parent-offspring relationships. We developed an SSR marker set for cultivar identification comprising 15 markers that were screened from 46 previously published SSRs. This marker set could be used for apple varieties including Malus × domestica and/or other Malus species. These SSRs successfully characterized 95 apples, including the leading and major founding cultivars used worldwide for modern apple breeding. Therefore, this marker set could be applied to almost all apple cultivars. We also analyzed the parent-offspring relationships of 69 cultivars by considering allele transmissions. This analysis revealed the true parentage of the following seven cultivars: ‘Kizashi’, ‘Chinatsu’, ‘Honey Queen’, ‘Haruka’, ‘Seirin’, ‘Ozenokurenai’, and Morioka #48. This analysis also revealed a parentage discrepancy for ‘Hacnine’. From the parent-offspring analysis, two microsatellite mutation events at alleles inherited from pollen parents were observed.     

A practical method for almond cultivar identification and parental analysis using simple sequence repeat markers

Early and accurate identification of almond [Prunus dulcis (Mill.) D.A. Webb] cultivars is critical to commercial growers and nurseries. Previously published simple sequence repeat loci were examined for their ability to distinguish commonly grown almond cultivars. Twelve highly polymorphic loci were selected for their ability to uniquely identify a set of 18 almond cultivars commonly grown in California, many of which are closely related. These markers also allow an accurate assessment of parent/progeny relationships among cultivars. This system can reliably identify at an early stage of development all major California almond cultivars in current production.     

Multiphase flow analysis in the flow field of a micro direct methanol fuel cell

The multiphase flow driven by the capillary pressure in the anode flow field of a micro direct methanol fuel cell (μDMFC) is modeled based on the porous media theory. The electrochemical reaction at the anode is taken into account in this model. Parametric studies of the channel size and the power density are carried out to assess the effects on the transport characteristics of the multiphase flow driven by the capillary pressure in micro channels. In addition, the effects of the channel size on the cell performance are discussed. The results show that the liquid saturation in micro channels increases with the increase of the width and height of the channel, but decreases with the increase of the channel pitch and the power density. The cell performance is improved with the increase of the channel width and height. A larger channel pitch and length lead to a lower power density.     

Improvement of vehicle air-conditioning duct and analysis of its impact on occupant thermal comfort

A numerical simulation on the air flow in vehicle air-conditioning duct is conducted by applying computational fluid dynamics（CFD）code Fluent and its result is compared to test result within a very small difference. Besides, the result shows that the distribution of air flow is so uneven that the thermal comfort of driver is rather poor. To improve it, the air-conditioning duct system is optimized by response surface methodology which took three structural dimensions of the deflector attached to it as design variables and considered the airflow ratio of the driver side and the overall airflow as optimized purposes, and then the thermal comfort analysis of the driver was performed to the improved air-conditioning system. As a result, the airflow ratio of the driver side is improved to 51.3% from 44.9% due to the optimized air-conditioning duct, as well as that the thermal comfort of the driver is obviously improved.     

Cytogenetic analysis of a long-term Triticum timopheevii (Zhuk.) Zhuk. cell suspension culture

In vitro culturing of plant cells can cause changes in karyotype. Chromosome variations following long-term propagation in suspension culture of Triticum timopheevii (Zhuk.) Zhuk. were studied by routine staining and C-banding. The culture was highly heterogeneous with respect to the number and structure of chromosomes. The modal class cells had a lower chromosome number than T. timopheevii (2n= 28). This data was confirmed by cytophotometric analysis of nuclear-DNA content. Frequencies of chromosome loss varied for different homoeologous groups. A^t genome chromosomes tended to be preferentially eliminated in cells of different ploidy levels. Deletions, insertions, translocations, telocentric chromosomes, isochromosomes and dicentrics and their derivatives were observed in cultured cells. Chromosomes of various homoeologous groups differed in the frequencies and spectra of re—arrangements, but most aberrations occurred in the G-genome chromosomes. In vitro chromosome modifications did not correspond to in vivo variation. Presumably, this difference was caused by differences in the mechanisms of adaptation to the environment at the levels of the cell and the whole organism. G-genome chromosomes were more frequently involved in this process, both in vivo and in vitro.