On the combined use of scratch tests and CLA profilometry for the characterization of polyester powder coatings: Influence of scratch load and speed

The prediction of the mechanical properties of polyester powder coatings is of paramount importance, as they have to undergo a wide variety of forces and deformations during their service life. Determine the response of polymeric coatings to the actual loading conditions can be, however, very troublesome as their properties are function of the material physical state, rate-dependence and yield and break behaviour. Further, the characterization of soft, contaminated organic surfaces such as polymers can often cause severe problems with reliability and imaging accuracy due to instrumental artefacts.This is therefore the context in which this paper investigates the capability of multiple parameters scratch tests joined with non-contact CLA profilometry and FE-SEM to detect the scratch response of polyester powder coatings for protective and decorative outdoor applications. Scratch tests with blunt contact geometry were used to evaluate the response of polyester coatings baked at different time-temperature programs and, so, at different stages of their curing process. In particular, being such coatings highly non-linear in their response to mechanical stress or strain, the influence from scratch load and speed was carefully taken into account. Analytical evaluations of the experimental results led to good correlations between the extent of the deformed zone after scratch, scratch parameters and curing operational settings. This allows mapping the scratch response of the polyester topcoats to broad ranges of both scratch parameters and curing conditions.     

最小二乘法在直线矢量化技术中的应用

由于在计算机中图象的存储和显示常常都是以离散的点阵方式进行的，因而给直线的识别带来了很大的困难。本文采用最小二乘法进行参数估计，以提取模式的特征，得到了比较简单的直线矢量化算法，该算法较好的克服了矢量化算法中存在的短线和畸变的缺陷。     

水下目标高分辨方位估计特征分解法的C30硬件实验研究

高分辨方位估计特征分解法是一类性能良好的方法，本文从水下阵列信号处理的实际应用出发，对这类方法进行了C30硬件实验研究，所得结果为高分辨技术的实际应用提供了重要依据文中构造了高分辨方位估计的C30硬件实验系统；并实现了高分辨方位估计的Pisarenko法、MUSIC法、Johnson法和最小摸（Mininorm）法；对高分辨实验系统进行了仿真实验和消声水池实验，并测试了各特征分解法的运行时间．结果表明，高分辨C30实验系统表现了良好的方位估计统计性能和实时性能     

A method for improving the performance of MVDR beamforming

I.IntroductionInbeamformingforsonaritisthemostinterestingfunctionthatonecanobtainthctimcwaveformoutputsofthedesiredsignaltobedetectcdwithanimprovcdSignal-to-NoiseplusInterferenceRatio(SNIR).ItiswellknownthatMVDRbeamforminghasoptimumcapabi1i-hesofsignalprotection,interferenccremovalandnoisercduction.NootherbeamformingtochniquecanyicldalargerincreascinSNIR.Itspoweroutputcanbeusedasawavenumberspectrum(bearing)estimation,whoseprecisionorreso1utionisdeterminedprimarilybySignal-to-NoiseRatio…     

液压驱动工程车辆牵引性能参数的配置与控制

研究了现行工程车辆牵引性能参数静态匹配理论的特点与不足,发现机械传动与液力机械传动车辆对波动剧烈的动态负荷适应能力极差,不能保证车辆始终在理想匹配点工作,利用行走机构打滑限制超载会丧失牵引功率,增加司机操作强度,结果使机器生产效率降低。提出了利用液压无级变速传动,进行恒功率速度自适应控制,动态工况下的牵引性能参数仍按照静态匹配理论计算,在行走机构全打滑前(滑转率δm=30%～35%)进行极限负荷控制的设计方法。结果表明,该方法可提高工程车辆动力性、经济性、作业生产率综合性能和实现自动化。     

Detector based on time-resolved ion-induced voltage in laser multiphoton ionization and laser-induced fluorescence

The time-resolved ion-induced voltages obtained from multiphoton ionization (MPI) in gases were applied, for the first time, together with time-resolved laser-induced fluorescence (TR-LIF) for fast detection of organic compounds in ambient air. The target compounds were polycyclic aromatic hydrocarbons (PAHs) and nitroaromatics. The concepts of the proposed method are presented and examined. It is shown that the MPI signals allow for estimation of the molecular weight, while the fluorescence data supply additional quantitative and qualitative information. A 3D data presentation is suggested for obtaining selectivity. The proposed dimensions are the MPI-based mass estimation, the maximum LIF wavelength and the measured fluorescence lifetime. Since all required data are acquired simultaneously and since the setup can be continuously operated, this analytical concept is suggested for on-line applications. The common air components are not ionized at the selected wavelengths and only the organic pollutants are detected under these conditions. Moreover, it is shown that the resonant MPI mode provides a certain level of selectivity. Therefore, this setup may become the basis of an air sniffer.     

NEW METHOD TO ESTIMATE SCALING OF POWER-LAW DEGREE DISTRIBUTION AND HIERARCHICAL NETWORKS

A new method and corresponding numerical procedure are introduced to estimate scaling exponents of power-law degree distribution and hierarchical clustering func tion for complex networks. This method can overcome the biased and inaccurate faults of graphical linear fitting methods commonly used in current network research. Furthermore, it is verified to have higher goodness-of-fit than graphical methods by comparing the KS (Kolmogorov-Smirnov) test statistics for 10 CNN (Connecting Nearest-Neighbor)networks.     

中、美、俄田径教材中发展速度方法的比较研究

通过比较中、美、俄3国田径教材中发展速度的方法，分析3国教材在速度构成、速度训练方法及体系安排等方面的差异，为教练员选择短跑速度训练方法和手段扩大视野。     

"同辉"号建造完工船舶的船型改进

一艘已经建造完工的船舶——“同辉”号油轮，因设计不当，导致试航速度仅为设计航速的55％，后经过采取最小限度的船型改进措施：18站至20站的船首部分加装球鼻首，以改善进流角和首舭涡；尾部0站至3站的底部进行线型修改，使水流流动变成尾纵流，以改善螺旋桨供水；其他部位均保持不变，以减小损失．模型试验和实船试航结果均表明，船型改进措施少而有效，实船试航速度竞达到了原设计航速，“同辉”号油轮最终顺利交船．     

定数截尾两参数指数——威布尔分布形状参数的Bayes估计

在不同的损失函数下,本文研究了两参数指数—威布尔分布(EWD)形状参数的Bayes估计问题.基于定数截尾试验,当其中一个形状参数α已知时,给出了另一个形状参数θ在三种不同损失函数下的Bayes估计表达式,并求得了可靠度函数的Bayes点估计.最后运用随机模拟方法,将Bayes估计和极大似然估计进行了比较.结果表明,LINEX损失下Bayes估计的精度比极大似然估计高.