Investigating Averaging Effect by Using Three Dimension Spectrum

The eddy current displacement sensor＇s averaging effect has been investigated in this paper, and the frequency spectrum property of the averaging effect was also deduced. It indicates that the averaging effect has no influences on measuring a rotor＇s rotating error, but it has visible influences on measuring the rotor＇s profile error. According to the frequency spectrum of the averaging effect, the actual sampling data can be adjusted reasonably, thus measuring precision is improved.     

宽带钢热连轧机选型配置与板形控制

通过测试并分析机组上游与下游机架对控制性能的不同要求、服役周期内工作辊和支持辊辊形变化及其对板形控制性能的影响,结合1700mm热连轧机进行的现场试验及工程应用实践,提出热轧上游机架应采用凸度控制能力较强的轧机机型,下游机架宜采用长行程窜辊型轧机机型,全机组均可采用强力弯辊和变接触轧制技术提高机组板形控制能力。     

220GHz回旋管多模自恰非线性模拟

采用了回旋管多模自洽非线性注-波互作用理论,在多个模式同时存在下,每个模式的纵向场随时间和空间变化,最终达到平衡状态。编制了多模自洽非线性计算程序,对220 GHz回旋管进行了数值计算,分析了回旋管中的模式竞争问题,验证了设计的合理性。     

基于BP网络的雷达目标距离像识别性能仿真

针对反向传播(BP)神经网络用于高分辨率雷达目标距离像分类的问题.讨论了对识别性能产生影响的主要因素:训练算法的选择、输入数据的预处理方法以及神经网络的参数设计。利用4种飞机模型的重点散射源二维分布测试数据和频率步进法得到目标的一维距离像,对于从不同方位角范围内获得的距离像,用BP神经网络对目标识别的性能进行了仿真测试,结果表明选择弹性传播算法或模拟退火弹性传播算法训练网络时具有更好的分类性能,而且对输入样本进行对数变换也有助于提高识别率。     

舰船目标实时一维距离像研究

针对线性调频脉冲信号提出了舰船目标一维距离像实时成像算法,给出了系统工作原理,并结合舰船目标的实测数据对该算法进行了仿真分析,同时讨论了该算法在信号处理中的具体实现流程,最后给出了实时成像结果。     

渤海某油田弱氧化复合解堵技术研究及应用

针对渤海某油田部分注水井修井及调剖作业后聚合物滞留导致常规酸化解堵效果不佳的问题,从聚合物污染机理出发提出采用弱氧化复合解堵措施对注水井进行解堵,通过岩心驱替等室内实验,研制出一种针对聚合物污染的弱氧化解堵剂PO-01,实验表明,4％PO-01可使0.8％HPAM黏度降低99.95％.该技术已经在现场应用6井次,措施后...     

Effects of dietary Chinese cured meat on lipid metabolism in rats

The effects of different fats on animal lipid metabolism were investigated in order to clarify the safety of cured meat. The physical effect of nitrite in the cured meat was also explored due to a increased concern of this compound as a food additive. Body weight, food intake, organ/body weight ratio and plasma lipid profiles were analyzed. Rats fed with cured meat fat did not show any differences in body weight and food intake, compared with the control, and no significant difference was observed among groups. However, lard-fed rats showed marked morphological alternations in aortic intima and liver tissue. The cured meat group did not show apparent morphological changes on aorta intima compared to the control. Rats that received lard diet had significantly elevated TC (2.27 ± 0.46 mmol/ml), higher LDL-C (0.78 ± 0.31 mmol/ml) but lower HDL-C (1.55 ± 0.14 mmol/ml). Lard-fed rats had elevated oxidized LDL in serum and MDA level in blood and liver. However, diets containing fresh fat (with/without added nitrite) or cured meat fat failed to show these detrimental effects.     

Discrimination between defective and non-defective Brazilian coffee beans by their volatile profile

The coffee roasted in Brazil is considered to be of low quality, due to the presence of defective coffee beans that depreciate the beverage quality. In view of the fact that coffee flavour is directly related to the volatile compounds produced during roasting, the objective of the present study was to perform a comparative evaluation of the volatile fraction of defective (black, immature, sour) and healthy coffee beans, in order to find possible chemical markers for detection of defective coffee beans in roasted coffee. Volatiles extraction and concentration was performed by solid phase micro-extraction (SPME) of the roasted coffee headspace, using a triple phase (divinylbenzene/carboxen/polydimethylsiloxane) fiber. Analysis of the volatile profiles was performed by GC–MS. The results obtained showed that the proposed methodology was adequate for extraction, concentration and analysis of the coffees volatile profile. Several substances were identified as possible markers for differentiating black, sour and immature beans from healthy coffee beans. Statistical analysis of the data by principal components (PCA) demonstrated that the volatile profile enables the differentiation of healthy and defective coffees. The data were separated into two major groups, one represented by immature and black beans and the other by healthy and sour coffee beans. Such results indicated that black and sour beans can be associated to fermentation of immature and of healthy beans, respectively.     

A modified formula for accurate determination of three‐dimensional birefringence of fiber using modified subfringe integration method

The development of the use of interferometric techniques in the study of the optical properties of materials encouraged many researchers to work on the derivation and development of the theoretical considerations and the equations used in the calculations of those properties. The form of these equations depends on the technique used and the cross section of the sample, and also on the method of calculating the optical path difference of light across the sample studied. A modified formula to calculate the three‐dimensional birefringence distribution of the fiber, without the need to determine the refractive indices of the fiber in the parallel and perpendicular directions, was presented. The phase distribution of the simulated and experiment interferograms was obtained using subfringe integration method. The results obtained from the new method were compared with the calculated results of a well‐known method (Z method) and the figures presented showed that the results of the two methods were close to each other.