赤潮光谱特征及其形成机制

采用海面以上光谱测量方法 (Above water method),利用美国FieldSpec® Dual VNIR光谱仪测量了丹麦细柱藻、中肋骨条藻、海洋褐胞藻等三种浮游植物赤潮以及红色中缢虫这一原生动物赤潮的离水辐射光谱数据。强调赤潮与正常海水的光谱差异在于687～728 nm波段的特征反射峰,指出了浮游植物赤潮与原生动物赤潮间的显著光谱差异,并认为可据此进行某些赤潮种类的遥感识别。给出了浮游植物赤潮光谱反射峰、吸收峰成因;红色中缢虫这一原生动物引起的水色异常,与其体内的共生藻类及浮游植物色素碎屑有关;其摄食偏好、与藻类的共生特性研究以及藻类常温下的荧光发射特性研究,将有助于加深对于红色中缢虫赤潮光谱成因的认识。     

The Study on Infrared Scattering of Red Tide

Based on analyzing the infrared laser’s transmitting characteristic in the seawater, the concept about the red tide infrared scattering coefficient is introduced. By analyzing the relationship between the red tide infrared scattering coefficient and the red tide’s density, we bring forward a new method of monitoring the red tide based on detecting the red tide infrared scattering coefficient. According to Mie scattering theory, the scattering efficiency factor and the scattering phase function of the red tide particles in the ocean are simulated and calculated. The result proves that, as the radiuses of the red tide particles increase, the scattering efficiency factor oscillates, and the swing decreases gradually, and then approaches to 2. From the results of the scattering phase function, it can find that the scattering of the red tide particles is mainly a forward scattering for the infrared laser. Therefore, by analyzing the scattering efficiency factor and the scattering phase function of the red tide particles in the ocean, it can prove the feasibility of this red tide monitoring method in theory.     

基于水体光谱特性的赤潮分布信息MODIS遥感提取

赤潮监测对于赤潮治理、预防,减少赤潮危害有着重要作用.通过分析东海赤潮多发区域实测遥感反射率曲线,比较赤潮水体与非赤潮水体的光谱特性差异,发展了一种针对MODIS传感器的赤潮水体分布信息遥感提取方法.应用实测资料对提取方法进行验证,发现在119组实测数据中,只有一组不能正确识别.将算法应用于MODIS卫星资料,对200...     

基于机载激光雷达监测海洋赤潮模型研究

提出了基于机载激光雷达应用于海洋赤潮的监测与预报方法,以检测激光水下后向散射光信号,实现对海洋赤潮藻密度信息的获取.引入赤潮藻散射系数的概念,建立了机载激光雷达的赤潮藻散射系数探测模型.通过仿真计算,证明该模型可以有效评估出赤潮藻密度的大小,进而实现对赤潮消长过程的判断.     

Structure and generation mechanism of blue whirls

Blue whirls are newly discovered blue rotating flames transitioned from fire whirls generated on liquid fuel surfaces. Compared with the traditional fire whirls, blue whirls have a distinct flame structure and are almost soot-free. Studies of the blue whirl are expected to promote the development of clean combustion theory and technology. In this paper, we numerically and theoretically investigate the lifting process of fire whirls and blue whirls, and then discuss their structure and transition mechanisms. In contrast to the explanations in the literature, it is found that blue whirls can be created without the occurrence of bubble-type vortex breakdown in the rotating flow. The blue whirl can be considered as a special form of lifted fire whirl with a considerable liftoff distance and without being blown out. According to the simulation, both blue whirls and fire whirls have the typical triple-flame structure. The unique structure of blue whirls is closely related to the thermal expansion of gas and the restriction of the radial flow by the axis. The theoretical solution of the unified lifting curve for fire whirls and blue whirls is obtained, which is qualitatively in agreement with the numerical result. There are 4 different branches in the lifting curve, two of which are stable, respectively representing fire whirls with small liftoff distances, and blue whirls with larger liftoff distances. The unstable branches between the stable branches lead to non-continuous transitions between fire whirls and blue whirls, as observed in the experiment. The current study explains the existing physical phenomenon and makes valuable predictions that may guide future experiments and simulations.     

一种简单的97小波滤波器及图像压缩性能的研究

小波提升方案是继多分辨分析之后的另一种非常有效的构造小波滤波器的方法。以构造双正交小波的Cohen-Daubechies-Feauveau定理为基础,利用提升方式构造了一个包含Cohen,Daubechies和Feauveau的著名97小波滤波器(CDF97)的小波滤波器族,获得了新的97小波滤波器,其图像压缩性能与CDF97相当,但其复杂度已大大降低,有利于ASIC的设计。     

基于提升小波的红外图像去噪算法与实现

介绍了提升小波原理,以及把提升小波应用于红外图像去噪的算法.研究了提升小波的硬件实现方法,根据FPGA器件具有快速逻辑处理能力的特点,采用流水线的加法及桶状移位操作指令,设计了一种适合FPGA实现的提升小波图像去噪的硬件结构.实验结果表明,以FPGA来实现基于小波变换的图像去噪方法与传统方法相比,在速度方面得到了很大的提高.     

二维提升的CDF(1,3)小波结合改进的SPIHT的渐进性无损图像压缩方法

针对传统小波变换计算复杂的缺点和多级树集合分裂算法(SPIHT)编码过程重复运算、存储量大的问题,提出了一种二维提升的CDF(1,3)小波结合改进的SPIHT的渐进性无损图像压缩方法。对整数CDF(1,3)双正交小波变换实现二维提升,利用提升的小波对图像做变换,提高了运算速度、便于硬件实现。对SPIHT算法加以改进,根据各个子图像的不同特点,改变扫描路线,采用四路并行分块处理的方法,提高了编码速度,降低了编解码过程的运算复杂度和时间消耗。利用提升的CDF(1,3)小波变换结合改进的SPIHT实现了渐进性无损图像压缩,证明了二维提升方案的有效性。     

气力提升系统气液两相流数值模拟分析

污水处理、油田采油、液态金属冷却反应堆和磁流体动力转换器等领域采用气力提升系统有其显著优势.由于不同液体介质与气体介质密度对气力提升系统性能影响较大,因此本文基于Fluent仿真软件,采用欧拉模型、k-ω剪切应力输运湍流模型数值模拟了氮气-水、氮气-煤油、氮气-水银及空气-水、氩气-水、氮气-水下气力提升系统内气液两相流动行为,分析了系统稳定时提升立管内气相体积分数、提升液体流量、提升效率、提升管出口处液体径向速度的变化规律.研究结果表明:1)氮气-水、氮气-煤油、氮气-水银系统中,提升管内液体介质密度越大,提升管内气相体积分数越小、提升液体流量越大、提升效率越高;2)空气-水、氩气-水、氮气-水系统中,提升管内气体介质密度越大,提升管内气相体积分数越小、提升液体流量越大、提升效率峰值越小;3)提升管出口处提升液体径向速度随气体充入量的不断增加而整体波动升高,最终管轴中心附近液体速度较大,管壁附近液体速度较小.本文研究成果为污水处理、气举采油、液态重金属冷却核反应堆和磁流体动力转换器等应用领域的气力提升技术的优化提供科学的理论基础.     

Annual Variation and Global Structures of The DE3 Tide

The SABER/TIMED temperatures taken in 2002 2006 are used to delineate the tidal signals in the middle and upper atmosphere. Then the Hough mode decomposition is applied with the DE3 tide, and the overall features of the seasonal variations and the complete global structures of the tide are observed. Investigation results show that the tide is most prominent at 110km with the maximal amplitude of 〉 9K, and exhibits significant seasonal variation with its maximum amplitude always occurring in July every year. Results from the Hough mode decomposition reveal that the tide is composed primarily of two leading propagating Hough modes, i.e., the （-3, 3） and the （-3, 4） modes, thus is equatorially trapped. Estimation of the mean amplitude of the Hough modes show that the （-3, 3） mode and （-3, 4） mode exhibit maxima at 110km and 90km, respectively. The （-3, 3） mode plays a predominant role in shaping the global latitude-height structure of the tide, e.g., the vertical scale of 〉 50 km at the equator, and the annual course. Significant influence of the （-3, 4） mode is found below 90 km, where the tide exhibits anti-symmetric structure about the equator; meanwhile the tide at northern tropical latitudes exhibits smaller vertical wavelength of about 30 km.     

提升小波加权自相关函数的基音检测算法*

随着计算机技术的发展,语音信号处理作为人机交互的重要渠道,其在复杂噪声环境下的特征值检测算法直接关系到计算机的运算效率。基音周期是语音特征值提取的重要参数之一。针对传统基音检测算法在噪声环境下检测精度低的问题,提出了一种基于自适应提升小波变换加权线性预测误差自相关函数的基音检测算法。该方法用多级提升小波近似系数加权求和的方法来弥补自相关函数随着时间延迟量的增加幅值衰减的缺陷;用线性预测误差自相关函数的方法来抑制共振峰的干扰,然后将两种方法结合来突出基音周期处的峰值。实验结果表明,与传统的自相关函数法和小波加权法相比,该方法能有效减弱共振峰的影响,突出基音周期处的峰值,提高基音周期检测精度,鲁棒性更好。     

Air viscous fingers in isotropic fluid and liquid crystals obtained in lifting hele-shaw cell geometry

Summary The air viscous fingers in glycerol, nematic and smectic liquid crystals are studied using the so-called lifting Hele-Shaw cell geometry. It is shown experimentally that in this case a critical velocity of lifting exists, below which the viscous fingers do not grow. The dependences of this velocity and critical wavelength upon various parameters are measured. The obtained experimental data in the case of small lifting angles are in satisfactory agreement with the phenomenological estimations for linear Hele-Shaw cells. The authors of this paper have agreed to not receive the proofs for correction     

一种基于提升小波的图像融合技术研究

针对红外与可见光图像进行提升小波变换后低频图像的特点,提出了一种低频分量的融合算法,高频分量采取邻域方差取大为准则进行融合,然后进行提升小波逆变换得到融合图像。通过与传统小波融合方法进行比较,并引入信息熵、清晰度、Xydeas-Petrovic客观性能指标对融合后的图像进行分析。实验结果表明不论从视觉效果还是从客观性能指标上,该算法都优于传统的融合方法。     

Linear stability analysis of the Hele-Shaw cell with lifting plates

The first stages of finger formation in a Hele-Shaw cell with lifting plates are investigated by means of linear stability analysis. At the beginning of lifting the square of the wavenumber of the dominant mode results to be proportional to the lifting rate (in qualitative agreement with the available experimental data), to the square of the length of the cell occupied by the more viscous fluid, and inversely proportional to the cube of the cell gap. This dependence on the cell parameters is significantly different of that found in the standard cell. On the other hand, our results show that the wavelength of the dominant mode decreases with lifting time, also in agreement with several experimental observations. Received: 16 April 1997 / Accepted: 23 October 1997     

Optical image compression based on adaptive directional prediction discrete wavelet transform

The traditional lifting wavelet transform cannot effectively reconstruct the nonhorizontal and nonvertical high-frequency information of an image. In this paper, we present a new image compression method based on adaptive directional prediction discrete wavelet transform (ADP-DWT). We first design a directional prediction model to obtain the optimal transform direction of the lifting wavelet. Then, we execute the directional lifting transform along the optimal transform direction. The edge and texture energy can be reduced in the nonhorizontal and nonvertical directions of the high-frequency sub-bands. Finally, the wavelet coefficients are coded with the set partitioning in hierarchical trees (SPIHT) algorithm. The new method holds the advantages of both adaptive directional lifting (ADL) and direction-adaptive discrete wavelet transform (DA-DWT), and the computational complexity is far lower than that in these methods. For the images containing regular and fine textures or edges, the coding preformance of ADP-DWT is better than that of ADL and DA-DWT.     

LabSView平台下电动起吊推车控制系统设计

针对当前电动起吊推车控制方法,采用模糊人工控制准确定位和智能控制性不好的问题,在LabSView平台下进行电动起吊推车控制系统优化设计,提出基于多线程串口非线性严格反馈的电动起吊推车控制系统设计方法。控制系统分为硬件设计和软件设计两大部分,系统总体构架分为数据采集模块、控制陀螺仪模块、执行器模块、上位机通信模块和人机交互模块等,根据模糊PID控制律进行电动起吊推车控制算法设计,以ADSP-BF537作为主控芯片进行控制器硬件设计,在LabSView平台下进行控制算法程序加载,实现软件开发设计。系统测试结果表明,采用该系统进行电动起吊推车控制,灵敏度较高,控制收敛误差较低,鲁棒性较好。     

Quantum Mutual Entropy Defined by Liftings

A lifting is a map from the state of a system to that of a compound system, which was introduced in Accardi and Ohya (Appl. Math. Optim. 39:33–59, 1999). The lifting can be applied to various physical processes.     

潮汐的平衡理论

根据潮汐的平衡理论，得出高，低潮涨落公式并对潮力作了计算。     

几类典型环境声的主观评价及感知特性分析

近年来,通过“注入”调控声以降低交通噪声烦恼感的声频注入法受到广泛关注。以交通噪声调控研究为背景,通过成对比较评价了4类典型声音(实验一)和4类典型交通噪声(实验二)的烦恼感。结果表明,有调声(纯音和复音)烦恼度最高,自然声最低(海潮声最佳),蓝色噪声是仅次于海潮声令人感觉舒适的声音;被试对交通噪声和白噪声的评价存在明显的分类偏好。分析心理声学特征发现人对声音的感知依赖于多方面因素,但声刺激的某一因素(如粗糙度或音调特别高)特别突出则会引起极大的反感。构建不相似度二维感知空间,维度1反映了声音类型间的差异,维度2表征了被试对不同类型声音的烦恼度评价;并且通过相关分析发现它们与谱结构参量相关性较强。接下来的研究中,可以通过调整交通噪声的谱下降值和时域上升时间等参量使其谱结构更接近于自然声,从而降低噪声烦恼度。