美国大学教学评估及其对中国高等教育的启示

美国大学和学院，学生对教师教学进行有效性评估。不同大学对教学有不同要求和标准；美国学术界对教学评估体系利与弊展开过辩论，而学生和老师的背景特征可能引起偏见。美国学生对老师进行教学评估的体系，对中国高等教育教学可能有一定的他石意义，但是，评估体系的现实条件有差异，中国不应当照抄或照搬美国教学评估，尤其应该摒弃将教与学关系扭曲为买方和卖方关系的观念。取其精华而弃其糟粕，建立适应中国的教学评估体系才能提高高等教育质量。     

Graph-Based Dimensionality Reduction for Hyperspectral Imagery: A Review

Hyperspectral image(HSI) contains a wealth of spectral information, which makes fine classification of ground objects possible. In the meanwhile, overly redundant information in HSI brings many challenges. Specifically, the lack of training samples and the high computational cost are the inevitable obstacles in the design of classifier. In order to solve these problems, dimensionality reduction is usually adopted. Recently, graph-based dimensionality reduction has become a hot topic. In this paper, the graph-based methods for HSI dimensionality reduction are summarized from the following aspects. 1) The traditional graph-based methods employ Euclidean distance to explore the local information of samples in spectral feature space. 2) The dimensionality-reduction methods based on sparse or collaborative representation regard the sparse or collaborative coefficients as graph weights to effectively reduce reconstruction errors and represent most important information of HSI in the dictionary. 3) Improved methods based on sparse or collaborative graph have made great progress by considering global low-rank information, local intra-class information and spatial information. In order to compare typical techniques, three real HSI datasets were used to carry out relevant experiments, and then the experimental results were analysed and discussed.Finally, the future development of this research field is prospected.     

警衔培训"督晋督"学员的功能性动作筛查结果分析

对26名"督晋督"参训学员(男性18、女性8)进行功能性动作筛查.结果 是FMS测试平均得分为12.38±2.66分,50.0％的学员存在疼痛问题,FMS分值的变化与年龄有着显著的相关性.     

网络处理模式匹配算法研究*

主要从多个角度研究了经典的15种单模式和7种多模式匹配算法,并以可编程网络处理器为测试平台对其中的5种单模式和4种多模式匹配算法分别在匹配时间、占用存储空间以及预处理时间方面进行了性能测试。根据测试得出了各自测试中的最优算法。     

导电轮胎烟囱胶缺陷的原因分析及解决措施

分析导电轮胎烟囱胶缺陷的产生原因并提出相应的解决措施。主要缺陷是烟囱胶被胎冠胶覆盖而不能外露从而无法形成贯穿胎面的导电通路。预口型形状设计不合理、口型板底板倒角宽度设计偏大、烟囱胶预口型出口宽度设计不合理、烟囱胶门尼粘度偏低、现场管控不到位等均会导致烟囱胶不外露。通过调整烟囱胶口型和预口型形状、改善胶料的门尼粘度、加强现场管控等措施,可解决烟囱胶不外露问题。     

PZT／Terfenol-D／PVDF层状复合磁电材料谐振特性

采用热压法制备出二层锆钛酸铅(PZT)／聚偏氟乙烯(PVDF)与1层Tb0.28Dy0.72Fe2(Terfenol-D)／PVDF叠层结构的三元复合磁电材料，研究了不同PVDF含量，以及不同层厚比tp／L对样品的介电常数、介电损耗、电阻率、谐振频率以及磁电转换系数αE33，αE31的影响规律，结果显示PVDF的含量和层厚比都存在最佳值(最佳值出现在产0．5，tp／L=2／7)，并且在这个最佳值处，磁电转换系数达到最大。     

双包络TI-环面蜗杆传动的二次包络分析

在一次包络分析的基础上,着重进行了二次包络齿面接触分析,推导出了蜗杆和蜗轮齿面方程。齿面接触分析表明：齿面呈双线接触,润滑条件好,承载能力大,在重型机械传动装置中具有实用价值。     

大液相负荷下斜孔塔板的流体力学性能

针对大液相负荷气液传质操作 ,通过冷模实验 ,重新确定了普通斜孔塔板的液体力学性能 ,并给出了新的关联式。同时基于普通正排斜孔塔板在大液量操作条件下压降大 ,泄漏和雾沫夹带严重等缺点 ,沿用梯形导向浮阀的思想 ,提出了变正排为斜排的改进方案 ,并在相同条件下对两者的液体力学性能进行初步比较。证明了斜排斜孔塔板是一种适合大液体处理量且操作弹性较宽的塔板     

Simulation of Nonstationary Spring Discharge Using Time Series Models

We present a detailed analysis and comparison of two time series models, i.e., ARIMA and ARIMA-GARCH, to simulate the discharge of a karst spring (Niangziguan Springs (NS) complex) in the northern China. Statistical tests for the residuals are applied to examine the reasonability of the models. Statistically, both models are reasonably good to simulate the mean value of the discharge of the NS complex. The statistical test shows that the residual discharge data have conditional time-varying variance and volatility clustering, known as heteroscedasticity of the data. Calibration test shows that the ARIMA-GARCH model gives a varying confidence interval, which can more effectively capture the heteroscedasticity of the data, comparing with a constant confidence interval in the ARIMA model. In the validation and application process, we applied two approaches to simulate the discharge data: (1) fixed models, and (2) evolving models. The confidence interval width monotonically increases in both fixed models, and the fixed ARIMA-GARCH model has faster increasing confidence interval width than the fixed ARIMA model. This suggests that the fixed time series models are only suitable for short-term prediction. However, we found that this drawback can be compensated by updating the model once new data become available. Our evolving models show more reasonable confidence interval width for both models. In addition, the application shows that the ARIMA-GARCH model is very sensitive to the data fluctuation. We also found the evolving ARIMA-GARCH model was able to return to the narrow confidence interval width once the fluctuation diminished. Hence, we conclude that the ARIMA-GARCH model is more suitable for the sequences with strong heteroscedasticity.     

PEN/PTT共混聚酯的熔融行为

利用差示扫描量热仪对不同配比的聚萘二甲酸乙二醇酯/聚对苯二甲酸丙二醇酯(PEN/PTT)共混体系的熔融行为进行了分析,发现在共混体系中两组分形成各自的晶体,PEN和PTT的熔点均随另一组分含量的增加而下降。根据Nishi-Wang方程,按300℃计算,由PEN/PTT共混体系中PEN熔点下降计算所得到的相互作用能密度为-0．214 2 J/cm~3,相互作用参数为-0．006 8,表明PEN/PTY共混体系在熔融态是热力学性质稳定的相容体系。