GPS技术在测量汽车参数上的应用

汽车的稳定性与其运动学参数(如速度,加速度及转弯半径)及汽车在垂直于路面方向上的位移(称为高度参数)、路面坡度角密切相关,采用传感器测量法很难实时监测汽车的这些参数。本文利用差分全球定位系统(DGPS)Trimble AG114实时地测量了汽车的行驶轨迹、经、纬度、高度参数以及路面坡度角,研究了汽车在垂直于路面方向上的位移与汽车的稳定性的关系,根据汽车的经、纬度坐标利用三点法获得了汽车的转弯半径,为车辆的稳定性监测提供了有效地手段。

癌症与精神病人亲属心身状况及改善对策的跨文化探讨

目的研究居澳华裔及国内癌症及精神病人亲属的健康状况。方法以深层面谈和电话会谈、问卷法调查居澳华裔、居国内的癌症和精神病患者及其亲属共288人。结果绝大部分亲属有不同程度的焦虑、抑郁，伴有失眠、疲劳、衰弱等症状。2.78％～11．11‰被诊断为焦虑症、抑郁症或各种心身疾病。癌症病人亲属的健康状况随病人病情的波动而变化；精神病人亲属的健康状况随病人病情的进展和时间的推移趋向稳定。国内组与澳洲组表现有一定的差别。他们希望有完善的机构与设施帮助照顾其患病的亲人。结论建立完善的机构为癌症及精神病患者提供照顾等服务，帮助其亲属进行有效的心理调节，保持心身健康，是21世纪的国际性课题之一。

柴油机中一氧化氮生成模型及其研究

本文阐述了柴油机中一氧化氮生成的理论模型,它用于一台四冲程多缸废气涡轮增压柴油机。对比表明,计算的排气NO排放变化趋势与实测变化趋势一致;但在数值上,单纯燃用柴油时模型预报值与实测值吻合较好,渗烧酒精时偏离较大。分析了上述现象的原因,并提出了改进的意见。同时讨论了影响一氧化氮生成的若干因素。

High-quality aluminum turbocharger impellers produced by thixocasting

The thixocasting process was chosen to produce the impellers as it is capable of producing castings with extremely high internal quality.Slugs cut from the DC cast bars are re-heated to the semi-solid casting temperature, and a specially-designed runner and gating system is used to prevent oxide from the surface of the slugs from becoming incorporated into the impeller.The technology used to produce the semi-solid impellers is described in detail.The semi-solid cast impellers, produced from an Al-Si-Mg-Cu alloy, are heat treated to the T6 temper.Results from testing are presented demonstrating that the impellers are free of porosity and other internal defects.Both mechanical property and fatigue data are presented showing that the semi-solid impellers have better properties than impellers produced by conventional casting and similar properties to forged and machined impellers.A short study is also described which identified suitable processing parameters to minimize hot tearing in the complex-shaped turbocharger impellers semi-solid cast from alloy 201.The surfaces of the impellers were examined using penetrant testing, and the results of modifying processing parameters on the propensity for surface cracking are presented.An aging study was performed to identify optimum mechanical strength.

Effective Thermal Conductivity for 3D Five-Directional Braided Composites Based on Microstructural Analysis

A method for predicting effective thermal conductivities(ETCs) of three-dimensional five-directional(3D5D) braided composites is presented. The effective thermal conductivity prediction method contains a digital image processing technology. Multiple scanning electron microscopy(SEM)images of composites are analyzed to obtain actual microstructural features. These actual microstructural features of 3D5D braided composites are introduced into representative volume element(RVE) modeling. Apart from applying actual microstructural features,compression effects between yarns are considered in the modeling of RVE,making the RVE more realistic. Therefore,the ETC prediction method establishes a representative unit cell model that better reflects the true microstructural characteristics of the 3D5D braided composites. The ETCs are predicted with the finite element method. Then thermal conductivity measurements are carried out for a 3D5D braided composite sample.By comparing the predicted ETC with the measured thermal conductivity, the whole process of the ETC prediction method is proved to be effective and accurate,where a relative error of only 2.9 % is obtained.Furthermore,the effects of microstructural features are investigated,indicating that increasing interior braiding angles and fiber fill factor can lead to higher transverse ETCs. Longitudinal ETCs decrease with increasing interior braiding angles,but increase with increasing fiber fill factor. Finally,the influence of variations of microstructure parameters observed in digital image processing are investigated. To explore the influence of variations in microstructural features on variations in predicted ETCs,the actual probability distributions of microstructural features obtained from the 3D5D braided composite sample are introduced into the ETC investigation. The results show that,compared with the interior braiding angle,variations in the fiber fill factor exhibit more significant effects on variations in ETCs.

Heavy Duty Natural Gas Single Cylinder Research Engine Installation, Commissioning, and Baseline Testing

Natural Gas (NG) Internal Combustion Engines (ICE) are a promising alternative to diesel engines for on-road heavy-duty applications to reduce greenhouse gas and harmful pollutant emissions. NG engines have not been widely adopted due to the lower thermal efficiency compared with diesel engine counterparts. To develop the base knowledge required to reach the desired efficiency, a Single Cylinder Engine (SCE) is the most effective platform to acquire reliable and repeatable data. A SCE test cell was developed using a Cummins 15-liter six-cylinder heavy-duty engine block modified to fire one cylinder (2.5-liter displacement). A Woodward Large Engine Control Module (LECM) is integrated to permit implementation of real-time advanced combustion control. Intake and exhaust characteristics, fuel composition, and exhaust gas recirculated substitution rate (EGR) are fully adjustable. A high-speed data acquisition system acquires in-cylinder, intake, and exhaust pressure for combustion analysis. The baseline testing shows reliable and consistent results for engine thermal efficiency, indicated mean effective pressure (IMEP), and coefficient of variance of the IMEP over a wide range of operating conditions while achieving effective control of all engine control and operation variables. This test cell will be used to conduct a research program to develop new and innovative control algorithms and CFD optimized combustion chamber designs, allowing ultra-high efficiency and low emissions for NG ICE heavy-duty on-road applications.

Defect and Temperature Effects on Complex Quantum-Dot Cellular Automata Devices

The authors present an analysis of the fault tolerant properties and the effects of temperature on an exclusive OR (XOR) gate and a full adder device implemented using quantum-dot cellular automata (QCA) structures. A Hubbard-type Hamiltonian and the Inter-cellular Hartree approximation have been used for modeling, and a uniform random distribution has been implemented for the simulated dot displacements within cells. We have shown characteristic features of all four possible input configurations for the XOR device. The device performance degrades significantly as the magnitude of defects and the temperature increase. Our results show that the fault-tolerant characteristics of an XOR device are highly dependent on the input configurations. The input signal that travels through the wire crossing (also called a crossover) in the central part of the device weakens the signal significantly. The presence of multiple wire crossings in the full adder design has a major impact on the functionality of the device. Even at absolute zero temperature, the effect of the dot displacement defect is very significant. We have observed that the breakdown characteristic is much more pronounced in the full adder than in any other devices under investigation.

分布式发电装置的“花样年华”——系统配置由应用决定，并带给用户更低的成本和更好的可靠性

无论用于供电或供热，分布式发电装置均可为全球工业和商业用户提供更低的成本，以及更好的可靠性。分布式发电装置的应用领域相当广泛，虽然一种应用与另一种应用之间可能在硬件上类似，但在电能或热能的使用上却存在着巨大差别。本文用6个案例详细介绍分布式发电装置广泛的应用范围。

Dielectric relaxation studies of binary mixture of β-picoline and methanol using time domain reflectometry at different temperatures

Complex permittivity spectra of binary mixtures of varying concentrations of β-picoline and Methanol(MeOH)have been obtained using time domain reflectometry(TDR)technique over frequency range 10 MHz to 25 GHz at 283.15,288.15,293.15 and 298.15K temperatures.The dielectric relaxation parameters namely static permittivity(ε),high frequency limit permittivity(ε∞1)and the relaxation time(τ)were determined by fiting complex permittivity data to the single Debye/Cole-Davidson model.Complex nonlinear least square(CNLS)fiting procedure was carried out using LEVMW software.The excess permittivity(ε_(0)^(E))and the excess inverse relaxation time(1/τ)^(E) which contain information regarding molecular structure and interaction between polar-polar liqids were also determined.From the experimental data,parameters such as effective Kirkwood correlation factor(geff),Bruggeman factor(fB)and some thermo dynamical parameters have been calculated.Excess parameters were fitted to the Redlich-Kister polynomial equation.The values of static permittivity and relaxation time increase nonlinearly with increase in the mol-fraction of MeOH at all temperatures.The values of excess static permittivity(ε_(0)^(E))and the excess inverse relaxation time(1/τ)^(E) are negative for the studied β-picoline MeOH system at all temperatures.