射孔孔眼中散射超声脉冲波的FEM模拟

采用有限元素法 ,分别数值计算了平底孔道、台阶式孔道和尖劈状孔道等 3种孔眼模型中不同中心频率 (10 0 k Hz、5 0 0 k Hz、1MHz)的散射超声脉冲波。计算结果表明 ,无论选用哪一种孔底模型 ,均可以得到较为明显的对应于孔底的声波信号。但是 ,孔道越不规则 ,使用的超声信号的主频越高 ,则孔底信号越差。为了兼顾孔底信号质量和信号采集、传输的代价 ,在未来的检测仪器中应采用尽可能低的测量频率 (低于 5 0 0 k Hz)     

浓香型瓶装酒库存过程中理化指标的变化

经过对1996年及1999年灌装的种子牌系列浓香型白酒的理化指标检测，发现在贮存过程中理化指标变化很大，总酸，固形物呈上升趋势，总酯，己酸乙酯呈下降趋势,其升降幅度与贮存时间相关，时间越长变化越大，贮存3年的高低度5个样平均总酸上升18．2％，28度样总酸上升28．3％，50度样总酸仅上升11％，固形物平均上升39．2％，28度样上升43％，50度样上升18％，总酯平均下降24％，28度样下降34％，50度样下降31％，己酸己酯平均下降32．4％，28度样下降59％，50度样下降32％，贮存6年的5个样总酸平均上升39．8％，28度样上升52％，50度样上升41％，固形物平均上升71．8％，28度样上升635＜50度样上升77％，总酯平均下降42．4％，28度样下降54％，50度样下降31％，己酸乙酯平均下降51．8％，28度样下降69％，50度样下32%.     

PTA装置压力离心机冲洗新技术

分析了仪征化纤PTA装置压力离心机运转效果不佳的原因,提出解决方案,改造实施后取得了很好的效果。     

Microbiological denitrification of red beet juice

The purpose of study was the determination of optimal conditions for red beet juice denitrification by Paracoccus denitrificans bacteria as well as the evaluation of the usefulness of microbiologically treated juice for the production of a natural colouring preparation for foods. Total reduction of nitrates was found during bacterial culturing at 25 and 30 °C, at an initial pH of 7.0-8.0 and juice osmotic pressure of 900-1100 mOsm/kg. Microbiological denitrification procedure affected colour, taste and aroma of the juice. However, the use of juice as food colouring and component was made feasible by acidification and partial evaporation of water together with volatile substances.     

高层建筑物整体形变的GPS监测

利用GPS观测数据 ,进行高层建筑物的整体形变监测模型和方法的研究是一项重要的工作。本文针对高层建筑物监测环境及其对监测快速、高精度的要求 ,尝试性地提出了高层建筑物整体形变模型 ,说明了模型应用要求和特点 ,详细给出了针对该模型的GPS监测方案 ,并用实例说明了模型和方案的实施步骤 ,实例分析得出了有益结论。     

万家寨引黄工程北干线输水损失分析

万家寨引黄工程北干线系统输水损失，是关乎输水运行成本和水资源有效利用的重要问题之一。由于各类建筑物施工方法，材料及工艺的差异。其输水损失差异较大，计算方法和计算参数各不相同，文章在对各类建筑物进行输水损失计算的基础上，分析了不同类型建筑物的输水损失特点，提出了减少水量损失的建议和设想。     

1/f Noise separated from white noise with wavelet denoising

The low-frequency noise in the devices often appears to be a superposition of 1/f noise and white noise, which are induced by different physical mechanisms or microscopic defects. The separation of the two noises is necessary especially in the characterization of quality and reliability by means of noise measurement. The traditional separation method is usually used in frequency domain with limited frequency range, and the estimated value of exponent index γ for 1/f^γ noise has considerable error when the ratio of 1/f noise and white noise is smaller than 20 dB. In this paper, based on wavelet denoising theory, a new method is proposed to separate 1/f^γ noise from white noise in time domain and can be used to estimate γ values with much better accuracy even if the ratio of 1/f noise to white noise in low enough.     

Suspension force and mechanism of debris flows

The paper discusses the postulated suspension force, by which it is possible to explain some enigmatic phenomena observed in different types of mass movements. This force is generated in thick suspensions as a result of friction between sinking solid particles and static water. The suspension force is related to the seepage force but they have opposite directions. Both forces form flow networks. Having explained the suspension force, the paper describes how this influences the movement of material, particularly in debris flows. Enigmatic features and the mechanism of debris flows and lahars are explained by virtue of the suspension force. Electronic Publication     

改进尿素包装工艺 不断提高产品质量

通过对尿素包装工艺的不断改进，提高了尿素粒度、减少粉尘含量，效果明显。