基于可编程逻辑器件技术的基本模型机实验的设计与实现

为了改进计算机组成原理实验效果,通过应用先进的复杂可编程逻辑器件(CPLD)技术,对基本模型机实验进行了设计与实现,给出了采用ispDesignEXPERT软件进行实验设计的方法和步骤,提供了一种新的实验模式。采用这种实验模式,能增加实验设计的灵活性,能激发学生学习的兴趣。

《计算机组成与结构》课程设计教学研究

《计算机组成与结构》作为计算机类学生需要重点掌握的一门专业课,其实践教学的一个关键环节是课程设计。本文通过对该课程中关于模型机整机教学知识点的分析,总结几年的课程设计经验,探讨了利用CMD+实验仪进行课程设计的相关内容。

Insights from advances in research of chemically induced experimental models of human inflammatory bowel disease

Inflammatory bowel disease(IBD),the most important being Crohn's disease and ulcerative colitis,results from chronic dysregulation of the mucosal immune system in the gastrointestinal tract.Although the pathogenesis of IBD remains unclear,it is widely accepted that genetic,environmental,and immunological factors are involved.Recent studies suggest that intestinal epithelial defenses are important to prevent inflammation by protecting against microbial pathogens and oxidative stresses.To investigate the etiology of IBD,animal models of experimental colitis have been developed and are frequently used to evaluate new anti-inflammatory treatments for IBD.Several models of experimental colitis that demonstrate various pathophysiological aspects of the human disease have been described.In this manuscript,we review the characteristic features of IBD through a discussion of the various chemically induced experimental models of colitis(e.g.dextran sodium sulfate-,2,4,6-trinitrobenzene sulfonic acid-,oxazolone-,acetic acid-,and indomethacin-induced models).We also summarize some regulatory and pathogenic factors demonstrated by these models that can,hopefully,be exploited to develop future therapeutic strategies against IBD.

DYNAMIC MODEL AND SIMULATION OF A NOVEL ELECTRO-HYDRAULIC FULLY VARIABLE VALVE SYSTEM FOR FOUR-STROKE AUTOMOTIVE ENGINES

In modem four-stroke engine technology, variable valve timing and lift control offers potential benefits for making a high-performance engine. A novel electro-hydraulic fully variable valve train for four-stroke automotive engines is introduced. The construction of the nonlinear mathematic model of the valve train system and its dynamic analysis are also presented. Experimental and simulation results show that the novel electro-hydraulic valve train can achieve fully variable valve timing and lift control. Consequently the engine performance on different loads and speeds will be significantly increased. The technology also permits the elimination of the traditional throttle valve in the gasoline engines and increases engine design flexibility.

PHS系统无线设备入网测试方法研究

PHS网络规模越来越大,为了保证现网设备的安全运行,支撑小灵通的服务品牌,PHS系统无线设备入网前的验证测试成为必不可少的环节。详细阐述了无线设备入网前验证测试的各种方法和步骤,主要包括:实验室模型机测试、外场试验田测试、话务指标分析以及用户投诉分析等。

Dynamic characteristic analysis of whole machine tools based on Kriging model

In order to study the variation of machine tools’dynamic characteristics in the manufacturing space,a Kriging approximate model is proposed.Finite element method(FEM)is employed on the platform of ANSYS to establish finite element(FE)model with the dynamic characteristic of combined interface for a milling machine,which is newly designed for producing aero engine blades by a certain enterprise group in China.The stiffness and damping of combined interfaces are adjusted by using adaptive simulated annealing algorithm with the optimizing software of iSIGHT in the process of FE model update according to experimental modal analysis(EMA)results.The Kriging approximate model is established according to the finite element analysis results utilizing orthogonal design samples by taking into account of the range of configuration parameters.On the basis of the Kriging approximate model,the response surfaces between key response parameter and configuration parameters are obtained.The results indicate that configuration parameters have great effects on dynamic characteristics of machine tools,and the Kriging approximate model is an effective and rapid method for estimating dynamic characteristics of machine tools in the manufacturing space.

Neural Network Inversion for Multilayer Quaternion Neural Networks

Recently, solutions to inverse problems have been required in various engineering fields. The neural network inversion method has been studied as one of the neural network-based solutions. On the other hand, the extension of the neural network to a higher-dimensional domain, e.g., complex-value or quaternion, has been proposed, and a number of higher-dimensional neural network models have been proposed. Using the quatemion, we have the advantage of expressing 3D （three-dimensional） object attitudes easily. In the quaternion domain, we can define inverse problems where the cause and the result are expressed by the quaternion. In this paper, we extend the neural network inversion method to the quatemion domain. Further, we provide the results of the computer experiments to demonstrate the process and effectiveness of our method.

Applicability of Mean Field Approximation to Numerical Experiments of Thermal Convection during the Cooling Period of Lake Biwa

This paper describes the applicability of a stochastic model to the numerical experiments of thermal convection carried out under the condition of the northern part of Lake Biwa, Shiga Prefecture, Japan. It was shown in the previous study that the temporal changes of vertical water temperature distributions during the cooling period between September and February can be reproduced by a simple 3D-CFD model. It was also pointed out that the spatial distributions of cooled water body sinking to the bottom due to water surface cooling represent similar features of forest gap distribution, which can be clarified by a stochastic model. The basic features of numerical experiments on thermal convection such as the spatial distribution of cooled water body are firstly shown with several cooling rates at water surface. Then, a stochastic model, which was originally introduced to explain forest gap dynamics, is shown with its MFA （mean field approximation） as first approximation of stochastic model. It is pointed out through the comparison of theoretical results by MFA with tuned model constants to numerical experiments that MFA with some refinement can be applicable to reproduce the basic features of simulated results to some extent, although further investigations are required to clarify the applicability of the model to more detailed mechanism of thermal convection such as size distribution of cooled water body, phase change of flow pattern, etc..

Evidence of Dual Scale Porous Mechanisms During Fluid Migration in Hardwood Species (Ⅱ) A Dual Scale Computational Model to Describe the Experimental Results

The second part of this paper is devoted to the computational modelling of transient water migration in hardwood. During re-saturation, the moisture content, measured during the process by using X-ray attenuation (see part 1 of this paper), increases quickly very close to the cavity, but requires a very long time for the remaining part of the sample to absorb the moisture in wetting. For this configuration and this material, the macroscopic approach fails. Consequently, a dual-porosity approach is proposed. The computational domain uses a 2-D axisymmetric configuration for which the axial coordinate represents the macroscopic longitudinal direction of the sample whereas the radial coordinate allows the slow migration from each active vessel towards the fibre zone to be considered. The latter is a microscopic space variable. The moisture content field evolution depicts clearly the dual scale mechanisms:a very fast longitudinal migration in the vessel followed by a slow migration from the vessel towards the fibre zone.The macroscopic moisture content field resulting from this dual scale mechanism is in quite good agreement with the experimental data.

Effect of wall temperature and random distribution of micro organic dust particles on their combustion parameters

The effect of wall temperature on the characteristics of random combustion of micro organic particles with recirculation was investigated. The effect of recirculating in micro-combustors is noticeable, hence it is necessary to present a model to describe the combustion process in these technologies. Recirculation phenomenon is evaluated by entering the exhausted heat from the post flam zone into the preheat zone. In this work, for modeling of random situation at the flame front, the source term in the equation of energy was modeled considering random situation for volatizing of particles in preheat zone. The comparison of obtained results from the proposed model by experimental data regards that the random model has a better agreement with experimental data than non-random model. Also, according to the results obtained by this model, wall temperature affects the amount of heat recirculation directly and higher values of wall temperature will lead to higher amounts of burning velocity and flame temperature.

The Application of a Smartphone in Ship Stability Experiment

The inclining experiment is the only regulatory tool to assess ship stability. This experiment is a time consuming process for both real-life tests and ship model experiments. The difficulty is mainly due to a bias in the measurement of heel angle. Nowadays, digital inclinometers are available, but they are expensive. In this study, the use of a smartphone application is presented for ship inclination and rolling-period tests. The idea consists of using accelerometer and gyroscope sensors built into the current smartphones for the measurements. Therefore, some experiments are carried out on an example trawler model to exhibit the uses and advantages of this method. The obtained results are in good agreement with those provided from the pendulum method and natural roll-period test. This application is new, easy, and more accurately assesses metacentric height during the inclining and rolling-period tests.

Experimental Researches of a Hydrogen Fuelled SI Engine

The paper presents the results of the experimental research which was carried out on the spark ignition engine, experimental model, fuelled with hydrogen by direct injection method, using qualitative load adjustment method for engine running control. Also, the hydrogen injection solution at the beginning of the compression stroke, after the inlet valve closing, assures the cylinder cooling by inlet air avoiding in that way uncontrolled ignition phenomena and inlet back fire. Using this fueling method avoided the abnormally hydrogen combustion phenomena＇s for stoichiometric dosage operating conditions, achieving -30 % engine power increase. Hydrogen engine runs with very lean mixtures, due to engine load qualitative adjustment, a dosage value that leads to a reduction of the engine power with -25% from maximum power value. This provides a higher engine efficiency at low loads, the best results was obtained for λ=2- 4 air-fuel ratio values. The influence of the mixture quality on burning process, on polluting and energetically engine performances at the fuelling with hydrogen using direct injection method are presented. Because of the higher combustion temperature, the NOx emission level is higher for λ=1 - 2 comparative to gasoline fuelled engine, but decreases a lot for leaner mixture values, λ〉2.5.

The Efficiency Improving of Traction Drive Test Bench with Supercapacitor Energy Storage System

For development of passenger electrical transport, it is necessary to use energy more rationally. One of methods of vehicle power efficiency increase is installation of on-board energy storage systems. For studying of system operation, it is necessary to carry out a lot of experiments, therefore it is favorable to use the test bench and its computer model for reduction of the number of physical experiments. In this article, the results of computer modeling for the optimization of traction drive test bench by adjusting of the operation parameters of supercapacitor energy storage are described. Test bench operation is considered in cases of the energy storage system working at various selected supercapacitor initial voltages. Maximal increase of possibility of vehicle test bench regenerative braking with minimal decrease of autonomous power supply mode possibility is investigated. There is estimated the energy storage system efficiency improving measures dependence from supercapacitor operational voltage ranges. Parameters at which the minimum losses of energy are observed are revealed. Dependence of energy storage system discharge power on the most admissible supercapacitor current is established.

Asymptotics of the goodness-of-fit test for a partial linear model with randomly censored data

In this paper, we discuss the problem of testing the hypothesis that the underlying regression isa partial linear model. A test statistic, which is based on the quadratic form of a cusum process of residuals,is proposed. The asymptotic distributions of the test statistic under null hypothesis and the local alternativehypothesis are given. The number simulation shows that the test is available.

Closed loop control design for the sense mode of micromachined vibratory gyroscopes

This paper presents a novel design method of force rebalance control for the sense mode of micromachined vibratory gyroscopes.Specific theoretical deductions are performed to identify a precise linear model of the open loop system of the sense mode,which is crucial for the PI controller design.The frequency responses obtained by experimental tests agree well with those calculated with the theoretical model,indicating the accuracy of the theoretical analyses.Experimental results demonstrate that the bandwidth of the closed loop is extended to 94.8 Hz from 2.3 Hz in the open loop and the quadrature signal is suppressed by about 64 dBV in the closed loop system.The overshoot and stable time in the step response of the closed loop system are measured to be about 15% and 35 ms,respectively.The mode-splitting gyroscope with the closed loop controlled sense mode achieves a scale factor of 41.0 mV/deg/s with nonlinearity of 0.09% and asymmetry of 1%,and a bias instability of 4.0 °/h with angle random walk of 0.171 deg/h1/2.

Experimental and Numerical Analysis of Natural Bio and Syngas Swirl Flames in a Model Gas Turbine Combustor

Turbulent reacting flows in a generic swirl gas turbine combustor model are investigated both numerically and experimentally.In the investigation,an emphasis is placed upon the external flue gas recirculation,which is a promising technology for increasing the efficiency of the carbon capture and storage process,which,however,can change the combustion behaviour significantly.A further emphasis is placed upon the investigation of alternative fuels such as biogas and syngas in comparison to the conventional natural gas.Flames are also investigated numerically using the open source CFD software OpenFOAM.In the numerical simulations,a laminar flamelet model based on mixture fraction and reaction progress variable is adopted.As turbulence model,the SST model is used within a URANS concept.Computational results are compared with the experimental data,where a fair agreement is observed.

The Effects of Simplest Little Higgs Model on the Spin Correlations in the Top Quark Pair Production at the LHC and ILC

In the simplest little Higgs model （SLH）, we study the spin correlations in the top quark pair production at the LHC and ILC. We find that the SLH always suppresses the tt spin correlations compared to the SM values. At the LHC, the suppression can be over 10% for mz, 〈 750 GeV. The SLH prediction value is outside the 1σ range of the experimental data from ATLAS, and within 1σ range of the experimental data from CMS. At the ILC, the SLH can sizably suppress the tt spin correlation for mz, approaching the center-of-mass energy √s. For example, the maximal suppression can reach -22.5%, -14.5%, and -9.5% for √s = 500 Ge V, 800 Ge V, and 1000 GeV, respectively. Therefore, the tt spin correlation at the ILC can be a sensitive probe for the SLH.

Study on the Effects of the Light CP-odd Higgs via the Leptonic Decays of Pseudoscalar Mesons

To explain the anomALously large decay rate of ∑＋→p＋μ＋μ-, it was proposed that a new mechanism where a light CP-odd pseudoscaJar boson of mAo = 214.3 MeV makes a crucial contribution. Later, some authors have studied the transition π0→e＋e- and γ→γA10 in terms of the same mechanism and their result indicates that with the suggested mass one cannot fit the data. This discrepancy might be caused by experimental error of ∑＋→p＋μ＋μ- because there were only a few events. Whether the mechanism is a reasonable one motivates us to investigate the transitions π0→e＋e-;η（η′）→μ＋μ-;ηc→μ＋μ-;ηb→τ＋τ- within the same framework. It is noted that for π0→ e＋ e-, the standard model （SM） prediction is smaller than the data, whereas the experimental central value of η→μ＋μ- is also above the SM prediction. It means that there should be extra contributions from other mechanisms and the contribution of A may be a possible one. Theoretically calculating the branching ratios of the concerned modes, we would cheek if we can obtain a univers mass for A10 which reconcile the theoretical predictions and data for all the modes. Unfortunately, we find that it is impossible conclude that the phenomenology does not favor such a to have such a mass with the same coupling｜gt｜. Therefore we light A10, even though a small window is still open.