动力总成声功率级评价方法的研究

利用归一化回归方法对声功率级进行研究,分析了五款动力总成WOT扫描工况声功率级,得到相应的回归方程、归一化方程及其标准误差。研究结果表明:WOT扫描工况下的动力总成噪声可用一元线性回归方程L_w=mlgn+b进行拟合,不同动力总成的拟合曲线可进行归一化处理,所得方法可用于评价及比较动力总成声功率级,且满足声功率级2级准确度的不确定度要求。

聚焦换能器声强和声功率测量方法研究

针对聚焦声场的特点,以及辐射力天平(RFB)只能获得单一功率指标的缺点,提出一种基于近场测量法的聚焦换能器声强和声功率评价方法。通过声场测量系统对聚焦换能器预聚焦区域中两个平面上的声压扫描测量,运用声强法得到聚焦换能器的声强分布以及辐射声功率。采用活塞换能器的远场测量法与近场测量法进行比对,两种方法得到的声功率误差不超过12%。比较预聚焦区域声功率值和焦点处声功率值,分析声功率评价方法的准确性。发现聚焦声场中不同位置处的声功率值一致性误差<5%,同一位置处的声功率值重复性误差<2%。结果表明,近场测量法适用于对聚焦换能器声强和声功率的评价,可有效避免直接测量对测量设备的损坏,同时还克服双水听器声强互谱法频率上限低以及测量系统相位不匹配的缺点。

基于熵值法的城市精明增长评价模型——以美国匹斯堡和中国嘉峪关为例

针对城市的精明增长问题进行研究,使用了层次分析法、熵值法等方法,分别建立了评价指标体系、成功率评价模型等。运用EXCEL、MATLAB等软件,建立了衡量城市增长计划成功率的评价指标体系;选取美国匹斯堡和中国嘉峪关这两个城市(实验城市)来进行研究,并同时选取另外两个城市精明增长较成功的城市——美国芝加哥和中国厦门(对照城市),作为发达国家和发展中国家城市的代表。随后根据精明增长的原则,为实验城市设计了新的增长计划,并评定其成功率,从而完成对发达国家和发展中国家城市精明增长情况的研究。

基于灵活性矩阵与优劣解距离的新能源功率预测评价方法

鉴于功率预测评价对电力系统运行和调度的重要性,文章充分考虑电网调度实际需求,从不同时期下机组的出力大小和不同时段下电网调度对预测精度的需求2个方面分析现有功率预测评价指标的不合理之处,并提出了新的准确率指标。首先,对不同时期下系统灵活性进行计算得到灵活性矩阵并对其进行预处理;其次,将处理后的灵活性矩阵输入到优劣解距离法(technique for order preference by similarity to an ideal solution,TOPSIS)模型中,根据评价对象与理想化目标的接近程度对不同时段的灵活性进行排序和归一化计算,得到不同时段下的权重系数矩阵,进而形成新的评价指标;最后,将所提的评价指标与其他指标进行对比。仿真结果表明,所提评价指标更能体现系统灵活性对功率预测评价的影响,满足实际调度的需求。

Fabrication and performance evaluation of the thermoelectric generation and performance measuring system

A novel thennoelectric generating and performance measuring system （TGPMS） was designed and fabricated. TGPMS can not only achieve the function of thennoelectric generation, but also measure the thennoelectric performance parameters of the bismuth-telluride-based thennoelectric device accurately. These thennoelectric performance parameters mainly include the dependence of the Seebeck coefficient of the thennoelectric device on the device＇s temperature in the low temperature range （about 40 ~ 190~C ）, and the dependence of the power output and thermoelectric conversion efficiency on the temperature dif- ference or output load. With the optimum load, the optimal value of the power output is 3.39W when the temperature difference reaches 231.2~C, and the optimal value of the conversion efficiency is 3.22% when the temperature difference reaches 208.9~C. TGPMS provides an experimental foundation for the application of the thennoelectric generators in the space field.

Traffic Flow Model Based on Power Flow

The article is research on the traffic situations of freeways. Different rules make different traffic situations. It is meaningful to research on traffic situations under different conditions. The author analyzes factors like traffic flow and safety, peflbrmance respectively, and proposes the theor3, basis for making more reasonable rules. The author first establishes evaluation system of traffic safety. Then, we compare the freeway network to power network to find a solution. and establish a traffic flow model based on power flow （TFPF）. It calculates power flow. So it applies the formula mode back to the traffic network, chalking up the perforumnce of the traffic condition. We utilize cellular automata （CA） method to simulate traffic circulation, and verify the accuracy of above model with the obtained data.

Performance evaluation of anti-radiation based on the gamma degradation process

In the environment of space radiation, the high-energy charged particles or high-energy photons acting on a spacecraft can cause either temporary device degradation or permanent failure. The traditional probability model is difficult to obtain reliable estimation of unit radiation resistance performance with small samples. Considering that different products will change differently after high-energy particle radiation, we construct a model based on the gamma degradation process. This model can efficiently describe the law of unit radiation resistance variation with the total radiation dose levels under the effect of the total dose and displacement damage. Finally, the proposed model is used to assess the anti-radiation performance of the N-channel power MOSFET device STRH60N20FSY3 produced by STM to obtain average unit radiation resistance, survival probability, survival function, etc.

Comparative evaluation of geological disaster susceptibility using multi-regression methods and spatial accuracy validation

Geological disasters not only cause economic losses and ecological destruction, but also seriously threaten human survival. Selecting an appropriate method to evaluate susceptibility to geological disasters is an important part of geological disaster research. The aims of this study are to explore the accuracy and reliability of multi-regression methods for geological disaster susceptibility evaluation, including Logistic Regression(LR), Spatial Autoregression(SAR), Geographical Weighted Regression(GWR), and Support Vector Regression(SVR), all of which have been widely discussed in the literature. In this study, we selected Yunnan Province of China as the research site and collected data on typical geological disaster events and the associated hazards that occurred within the study area to construct a corresponding index system for geological disaster assessment. Four methods were used to model and evaluate geological disaster susceptibility. The predictive capabilities of the methods were verified using the receiver operating characteristic(ROC) curve and the success rate curve. Lastly, spatial accuracy validation was introduced to improve the results of the evaluation, which was demonstrated by the spatial receiver operating characteristic(SROC) curve and the spatial success rate(SSR) curve. The results suggest that: 1) these methods are all valid with respect to the SROC and SSR curves, and the spatial accuracy validation method improved their modelling results and accuracy, such that the area under the curve(AUC) values of the ROC curves increased by about 3%–13% and the AUC of the success rate curve values increased by 15%–20%; 2) the evaluation accuracies of LR, SAR, GWR, and SVR were 0.8325, 0.8393, 0.8370 and 0.8539, which proved the four statistical regression methods all have good evaluation capability for geological disaster susceptibility evaluation and the evaluation results of SVR are more reasonable than others; 3) according to the evaluation results of SVR, the central-southern Yunnan Province are the highest sus-ceptibility areas and the lowest susceptibility is mainly located in the central and northern parts of the study area.