间歇曝气脱氮系统的影响因素研究

通过观察间歇曝气生物脱氮系统在不同水温、C/N值下的脱氮效率以及好氧/缺氧一周期内的硝化和反硝化过程,分析了温度和缺氧期C/N值对硝化和反硝化速度的影响,探讨了冬季所需外加碳源量。试验结果表明,秋、冬季提高缺氧期C/N值是保障间歇曝气脱氮系统运行效率的有效措施;在TN负荷为0.034kg/(kgMLVSS·d),水温为15℃时最适C/N值为7,10℃时最适C/N值为9。为了降低冬季运行费用,有必要寻找廉价的外碳源。     

The stretch zone of automotive steel sheets

The paper deals with an experimental determination of the stretch zone dimensions in the notch tip in thin steel sheets. The stretch zone dimensions depend on steel grade, on the rolling direction as well as on the loading rate. Stretch zones were observed and measured on three steel grades. Fracture area and stretch zones were analysed by SEM. Stable crack growth was monitored by videoextensometry techniques on CT (Compact Tension) specimens. Specimens were loaded under two loading rates by eccentric tension, whereby the deformation in the notch surrounding area was recorded using a non-contact measurement–videoextensometry technique. Linear relation between the stretch zone dimensions was determined.     

Investigating the tension load of rubber composites by impact dynamic testing

This work deals with establishing the tension load by impact dynamic testing of rubber composite conveyor belts. The value of tension load affects the shape of the used impactor and use of a support system as well as the weight of the ram and the impact height. An increase in the allowable stress when the belt is tensioned was examined during the test, to determine the effect of impact on the tension load. The obtained values of tension load are assessed using basic mathematical and statistical methods. Using the Design of Experiments method, factors that significantly affect the value of the tension load are identified.     

喷涂房循环水槽涂漆解黏处理技术

在工业喷漆生产线,大约有25%～60%的涂漆由于超过量喷涂而损耗。在大型喷漆作业线如汽车行业,过喷的涂漆会被循环水系统所收集,然后采用传统的化学涂料解黏系统进行处理。本文介绍了循环水槽涂漆常用的化学、生物及生化处理工艺,并对结合了化学-生物处理方法开发出来的KleerAid生化涂漆解黏工艺与传统工艺进行了比较。生产应用表明,该生化工艺对水质的COD值、总悬浮物值、污泥含水率、污泥的解黏程度均优于传统的化学解黏工艺,提高了整体循环水处理的成本效益。     

基于频域系统辨识和支持向量机的桥梁状态监测方法

随着大跨度悬索、斜拉桥的增加,保障桥梁安全、降低维护费用成为交通管理以及政府部门关注的问题。针对损伤样本难以获得的实际情况,将桥梁状态监测问题作为模式识别中的“一类学习”问题处理。桥梁模式特征获取过程是“只有输出响应”的系统辨识问题,考虑到监测系统需要在线工作的特点,提出运用概念直观、结果可靠且便于自动实现的CMIF系统辨识方法作为获取模式特征的工具。为了获得足够敏感的异常报警判别函数,采用了基于支持向量机的一类学习算法,这种方法在得到很高灵敏性的同时,可以方便地权衡敏感性和泛化性能之间的矛盾。用香港汀九桥794小时实测数据对所采用的算法进行验证,证明了算法的有效性和实用性,其结果可供设计类似监测系统时参考。     

Velocity invariance of receptive field structure in somatosensory cortical area 3b of the alert monkey

This is the second in a series of studies of the neural representation of tactile spatial form in cortical area 3b of the alert monkey. We previously studied the spatial structure of 330 area 3b neuronal receptive fields (RFs) on the fingerpad with random dot patterns scanned at one velocity (40 mm/sec; ). Here, we analyze the temporal structure of 84 neuronal RFs by studying their spatial structure at three scanning velocities (20, 40, and 80 mm/sec). As in the previous study, most RFs contained a single, central, excitatory region and one or more surrounding or flanking inhibitory regions. The mean time delay between skin stimulation and its excitatory effect was 15.5 msec. Except for differences in mean rate, each neuron's response and the spatial structure of its RF were essentially unaffected by scanning velocity. This is the expected outcome when excitatory and inhibitory effects are brief and synchronous. However, that interpretation is consistent neither with the reported timing of excitation and inhibition in somatosensory cortex nor with the third study in this series, which investigates the effect of scanning direction and shows that one component of inhibition lags behind excitation. We reconcile these observations by showing that overlapping (in-field) inhibition delayed relative to excitation can produce RF spatial structure that is unaffected by changes in scanning velocity. Regardless of the mechanisms, the velocity invariance of area 3b RF structure is consistent with the velocity invariance of tactile spatial perception (e.g., roughness estimation and form recognition).     

Diagnostic accuracy of a rural live video telepathology system

Accuracy of diagnoses rendered using a live video telepathology network was assessed for permanent sections of surgical pathology specimens. To determine accuracy, telepathology diagnoses were compared with those obtained by directly viewing the glass slide using a standard microscope. A total of 294 cases were read via both telepathology and glass slide by attending pathologists at a tertiary care medical center. Overall accuracy was defined as exact concordance between diagnoses. Clinically insignificant differences in diagnoses were excluded to determine clinically significant accuracy. For the 285 cases with complete data, the overall accuracy for telepathology was 0.912 (95% confidence interval [CI], 0.872-0.941), whereas the overall accuracy for glass slide readings was 0.968 (95% CI, 0.939-0.985). This difference is statistically significant (p = 0.009). When focusing on clinically significant discrepancies, where the difference in diagnosis might affect therapeutic decisions, the video accuracy was only slightly less than the glass slide accuracy (0.965 [95% CI, 0.934-0.982] vs. 0.982 [95% CI, 0.957-0.994], respectively), but this difference is not statistically significant (p = 0.302). Most of the cases with clinically significant differences involved lesions with inherently high interobserver variation. Certainty of diagnosis did not differ between video and glass slide readings (p = 0.911), but there was an association between certainty of diagnosis and diagnostic accuracy for video (p = 0.003 for clinically significant accuracies). Based on these findings, we recommend when using this telepathology system that only preliminary diagnoses should be given in the following situations: for diagnostic areas with known high interobserver variability; when the consultant has any degree of uncertainty about the presence or absence of the lesion in question; and when there is insufficient experience using telepathology as a diagnostic medium.