一类耗散非线性波动方程初边值问题整体解的存在与非存在性

本文考虑一类耗散非线性波动方程的初边值问题。用半(?)方法和先验估计论证了该问题小初值下在时间大范围的可解性、唯一性;并用凸性方法证明了(?)当条件下该问题的解在有限时间内发生爆破现象。     

Application of acoustic Doppler current profiler combined with a scientific echo sounder for krill Euphausia pacifica density estimation

ABSTRACT:   An application of the acoustic Doppler current profiler (ADCP, 153.6 kHz) in combination with a scientific echo sounder (EK60, 38 and 200 kHz) was investigated to estimate the density of krill Euphausia pacifica . The acoustic backscattering strength from sound scattering layers was compared with biomass estimates from midwater trawls. Euphausia pacifica was targeted among mixed species populations in the sound scattering layer in the offshore Funka Bay area of Hokkaido, Japan. The frequency characteristics of acoustic backscattering by krill were calculated using a distorted wave Born approximation scattering model at three frequencies. Krill aggregations identified from the EK60 data were extracted as the mean volume backscattering strength difference between two frequencies. They were then used to identify similar aggregations in the ADCP data by matching observation times and depths for the two methods, which were applied simultaneously. Results from the comparison of the mean volume backscattering strength and the density calculated from the ADCP and EK60 showed that ADCP can be used to measure density and spatial–temporal distribution of krill aggregations. Current speed and direction at the study site were found to be 16.1 cm/s and 187.0°, respectively, and krill speed and direction (including the current component) were found to be 19.8 cm/s and 172.2°, respectively. Based on the ADCP data, the net speed and direction of the krill aggregations were found to be 5.9 cm/s and 128.0°, respectively.     

The Location Algorithm of QRS Waves Based on Fractal Box Dimensions Detection Methods

We research fractal characteristics of ECG signal, and find that it is logarithmic linear relationship between the boxes number covering signal and box scale. It is shown that ECG signal have some characteristics. Further more, we discover that fractal dimensions at QRS site are higher than others when using a time windows to detect signal. Based on this foundation, we raise a location algorithm of QRS waves which is based on fractal boxes dimension detection methods. The application results of this algorithm show that it can get rid of noise in ECG effectively with high speed, so this algorithm can be used in real time detection of ECG signal.     

方波伏安法快速测定饲料中磷含量

运用方波伏安法快速测定溶液中过量的铅离子从而间接测定无机磷含量。在最佳试验测定条件下方波伏安峰高ip(μA)与磷的浓度(c)在0.2～20μg/mL内有良好的线性关系,回归方程为ip=54.82-2.39c,相关系数r=0.9876,检出限为0.085μg/mL,相对标准偏差(RSD)为2.44%,加标回收率为95%～99%。     

天山地形对新疆大风和降温天气作用的数值模拟研究

2009年5月24日夜间～26日夜间,新疆地区自西向东出现了明显的降水、大风、降温天气过程。为研究此次天气过程中天山地形的作用,文中用WRFV3.1模式对其进行了数值模拟,并通过改变天山山脉的地形高度设计了一组敏感性试验,分析了天山地形对此次强天气过程中大风和降温的影响。结果表明,天山山脉地形对准格尔盆地西北部直至天山山脉北侧的气流有明显的阻挡与减缓作用,对三十里风区、百里风区、汗腾格里峰北坡强风带的形成有直接而重要的作用;地形高度越高,产生垂直运动的地形抬升机制越强,地形强迫抬升作用产生的垂直上升运动越剧烈;天山山脉明显地减轻了寒潮天气过程中南疆塔里木盆地的降温幅度,对准格尔盆地北部的寒潮降温幅度也有一定的减缓作用,对塔里木盆地的"保温"作用较准格尔盆地明显。     

波浪补偿控制算法综述

为了实现对船舶在波浪中的运动响应进行补偿,提高海上作业的效率,需要对波浪补偿设备采用更为先进的运动控制技术.采用前馈控制和反馈控制的分类方式,简述了适合用于波浪补偿设备的控制算法研究现状,以便于更好地了解波浪补偿控制技术的发展.其中,属于前馈控制类算法的主要有卡尔曼滤波法、神经网络和时间序列分析法;属于反馈控制类的主要...     

300Hz脉冲音对许氏平鲉幼鱼的驯化效果

采用300 Hz脉冲波断续音在实验室水槽中对许氏平鲉Sebastes schlegeli幼鱼进行音响驯化试验。结果表明：在驯化第15天开始聚集时间减小到2 s,之后到20 d均无大变化;聚集时间从第5天开始整体呈递减趋势,驯化第16天,聚集时间达到最短（16 s）;聚集率则逐日增加,驯化第18天,聚集率达到最高,为91%,平均聚集率为83.9%;音响驯化结束10 d后再次放声,许氏平鲉开始聚集时间为3 s,聚集时间为44 s,聚集率为86.3%。由此可见,300 Hz脉冲波断续音对许氏平鲉有明显的驯化作用;许氏平鲉对驯化声音记忆力超过10 d且效果显著。     

超声波辅助提取葛根黄酮的工艺研究

采用超声波提取法,研究了乙醇浓度、固液比、超声波提取时间、超声波功率4个因素对葛根（Puerariae lobata（Willd.） Ohwi）黄酮提取率的影响,并采用L8（27）正交试验确定超声波提取葛根黄酮的最优工艺。结果表明：超声波作用时间与固液比对葛根黄酮得率有显著影响（P〈0.05）,并且其交互影响显著（P〈0.05）。优化的葛根黄酮提取条件为：乙醇浓度70％、料液比1：25、超声功率240W、超声时间40rain。     

超声波对尼罗罗非鱼幼鱼生长的影响

选择尼罗罗非鱼Tilapia nilotica幼鱼(平均体重为1.95 g±0.60 g)为试验对象,用3种不同强度的超声波对其进行辐射刺激,共设3个试验组和1个对照组。经过60 d的超声波辐射养殖,结果表明:各组间体重存在极显著性差异(P<0.01),其中每天受频率为23 kHz、声源声强为200 mW/cm2的连续超声波辐射刺激5 min的试验组鱼,其体重最高,比对照组鱼体重增长约7.58%;但每天受频率为23 kHz、声源声强为600 mW/cm2的连续超声波辐射刺激5 min的鱼体,其体重反而比对照组体重减少约5.80%。各试验组尼罗罗非鱼体重与胃蛋白酶活性之间没有明显关系。当环境声强为1.58~1.60 mW/cm2时,对尼罗罗非鱼幼鱼生长比较有利。     

星点设计-效应面法优化梓树果实总黄酮的超声提取工艺

以梓树果实为材料,利用星点设计—效应面法对总黄酮的超声提取工艺参数进行优化研究。选择乙醇浓度、料液比、提取时间为自变量,总黄酮提取量为因变量,对自变量各水平进行多元线性回归和多项式拟合,采用效应面法选取较佳工艺条件,并进行预测分析。结果表明:梓树果实总黄酮的最佳提取工艺参数为乙醇浓度59%,料液比1∶44,提取时间39 min。在此工艺条件下梓树果实总黄酮提取量测定值为22.289 4 mg.g-1,最佳工艺验证结果与模型预测值相差-1.84%。