一种基于多源遥感影像的亚端元光谱提取方法     

朱长富  吴波  吴逸人  高海燕 《测绘科学》2009,34(4)

提出一种利用多源影像来提取低分辨影像亚端元光谱的方法,该方法利用高分辨分类得到的组分与低分辨的光谱之间的线性混合关系,建立了反演出低分辨影像的亚端元光谱的线性模型,并提出一种快速鲁棒反演亚端元光谱的提取方法。利用IKONOS和ETM数据验证了本文提出方法,实验结果表明了该方法的有效性。  相似文献   

Large-scale dune erosion tests to study the influence of wave periods   总被引：1，自引：0，他引：1  

M.R.A. van Gent  J.S.M. van Thiel de Vries  E.M. Coeveld  J.H. de Vroeg  J. van de Graaff 《Coastal Engineering》2008,55(12):1041-1051

Large-scale physical model tests were performed to quantify the effects of the wave period on dune erosion. Attention was focussed on 2D cross-shore effects in a situation with sandy dunes and extreme water levels and wave conditions. Besides profile measurements, detailed measurements in time and space of water pressure, flow velocities and sediment concentrations were performed in the near near-shore area. It was concluded that a longer wave period leads to a larger dune erosion volume and to a larger landward retreat of the dune face. Tests with double-peaked wave spectra showed that the influence of the spectral shape on dune erosion was best represented by the T_m − 1,0 spectral mean wave period, better than the peak wave period, T_p. The effect of the wave period on dune erosion was implemented in a dune erosion prediction method that estimates erosion volumes during normative storm conditions for the Dutch coast. More details of the measurements and additional analyses of physical processes are described in an accompanying paper by Van Thiel de Vries et al. [Van Thiel de Vries, J.S.M., van Gent, M.R.A., Reniers, A.J.H.M. and Walstra, D.J.R., submitted for publication. Analysis of dune erosion processes in large scale flume experiments, In this volume of Coastal Engineering.].  相似文献   

光谱对许氏平鲉消化代谢节律及生理应激研究          下载免费PDF全文

房莹莹  陈璐璐  刘松涛  孙飞  吴燕玲  李鑫  刘鹰  马贺 《海洋科学》2023,47(10):94-111

为探究不同光谱下许氏平鲉的消化代谢水平及外周激素节律,在5种光谱(红光、绿光、黄光、蓝光、白光,光周期12L∶12D)下,通过对许氏平鲉的血清、肠道、肝脏进行24 h (8:00,12:00,16:00,20:00,24:00)取样,结果显示:不同的光谱下许氏平鲉的消化代谢酶活性除胰蛋白酶(TRY)外均具有节律性,红光、黄光下α-淀粉酶(α-AMS)、脂肪酶(LPS)活性的峰值相位与白光组相比左移;胰蛋白酶活性无时间差异性;在绿光、黄光及红光下乳酸脱氢酶(LDH)活性的峰值相位与白光组相比发生左移,在五种光谱环境中,红、黄光影响消化酶活性峰值提前出现;丙酮酸激酶(PK)活性在绿、蓝及红光下峰值相位左移;己糖激酶(HK)的活性在绿、蓝、黄光下,其峰值相位与白光组相比发生左移,在五种光谱环境中,绿、蓝光影响代谢酶活性类峰值提前出现。许氏平鲉血清中褪黑素含量呈现昼低夜高分泌水平;皮质醇的含量表现为在白天降低,午夜显著升高至最高值后又持续降低。峰值相位的改变预示着生理节律的变动,以上结果表明不同光谱可以影响鱼类的生理代谢节律,在今后养殖过程中需要充分考虑光谱对养殖生物的生物学作用,进而制定更为合理的光照条件。  相似文献   

大黄鱼病原副溶血弧菌拮抗菌的筛选   总被引：1，自引：1，他引：0       下载免费PDF全文

郭国军  覃映雪  陈强  邹文政  鄢庆枇 《海洋学报》2008,30(1):127-134

用点种法从大黄鱼肠道优势菌群中筛选出104株病原性副溶血弧菌的拮抗菌,进一步研究拮抗效果最好的11株拮抗菌的抗菌谱和生长曲线,其中NAC平板上筛选的4株拮抗菌的抗菌范围较广,锰营养琼脂培养基上筛选的3株拮抗菌具有生长优势。用BIOLOG板测定了抗菌谱较广、有一定生长优势3株拮抗菌(R22,Y58和J312)的碳源利用情况,结果表明,3株拮抗菌的碳源谱都比较广,都能利用糖类、有机酸和氨基酸等,而且与鱼类营养的竞争较小。16S rRNA基因同源性分析的结果显示与R22,Y58,J312同源性达99%以上的菌株分别来自弧菌属、芽孢杆菌属和假单胞菌属。进一步对R22,J312和Y58三株拮抗菌进行生化鉴定,结果显示R22为溶藻弧菌,J312为荧光假单胞菌,但Y58的种属未能得到确认。所得到的3株拮抗菌R22,Y58,J312在拮抗病原菌、抗菌谱、生长特性和营养利用等方面都初步满足益生菌的筛选条件,有待进一步检测其安全性和实用效果以便能够成为能实用的益生菌。  相似文献   

Large-scale variability in the profiles of Hα and Hβ in the spectrum of the Herbig B8e star MWC 419 and a model interpretation of it     

A. V. Kurchakov  M. A. Pogodin  F. K. Rspaev 《Astrophysics》2007,50(2):207-224

Spectroscopic data taken with a moderate resolution spectrograph in the region of the Hα and Hβ lines are presented for the Herbig B8e star MWC 419. The spectroscopic observations were accompanied by broad band BVR photometric measurements. The observations reveal a variability in the line profiles that is typical of Herbig Ae/Be stars with signs of a strong stellar wind. The greatest changes are observed in the region of the absorption components of the line profiles, which convert the profile from a type P CygII to P CygIII, as well as in the intensities of the central emission components. A model technique is used for quantitative interpretation of this variability and it shows that the P Cyg profile conversion of the absorption component can be explained in terms of a stellar wind model in which its distribution over latitude varies on a time scale of a few days. __________ Translated from Astrofizika, Vol. 50, No. 2, pp. 259–280 (May 2007).  相似文献   

悬链线法在水平定向钻轨迹设计中的应用探究     

杨先亢  兰海涛  遆仲森  马保松 《岩土钻凿工程》2010,(1):47-50

铝孔轨迹设计是非开挖水平定向钻施工中一项重要内容。其最优化设计在国内已较成熟,但多数优化设计未从力学方面进行优化设计。针对这一情况,引入悬链线法来优化水平定向钻轨迹设计。通过悬链线法的计算可知,优化后的轨迹不仅有利于降低钻杆回转阻力和扭矩消耗,提高机械钻速,增长管道使用年限,同时与传统设计方法相比较,其计算出的轨迹长度也比传统圆弧轨迹长度略短,表明了悬链线法在水平定向钻轨迹设计上具有一定的优势。  相似文献   

Estimation of the Land Surface Emissivity in the Hinterland of Taklimakan Desert   总被引：3，自引：2，他引：1  

LIU Yong-qiang  Ali MAMTIMIN  HUO Wen  YANG Xing-hua  LIU Xin-chun  MENG Xian-yong  HE Qing 《山地科学学报》2014,(6):1543-1551

An accurate accounting of land surface emissivity(ε) is important both for the retrieval of surface temperatures and the calculation of the longwave surface energy budgets.Since ε is one of the important parameterizations in land surface models(LSMs),accurate accounting also improves the accuracy of surface temperatures and sensible heat fluxes simulated by LSMs.In order to obtain an accurate emissivity,this paper focuses on estimating ε from data collected in the hinterland of Taklimakan Desert by two different methods.In the first method,ε was derived from the surface broadband emissivity in the 8–14 μm thermal infrared atmospheric window,which was determined from spectral radiances observed by field measurements using a portable Fourier transform infrared spectrometer,the mean ε being 0.9051.The second method compared the observed and calculated heat fluxes under nearneutral atmospheric stability and estimated ε indirectly by minimizing the root-mean-square difference between them.The result of the second method found a mean value of 0.9042,which is consistent with the result by the first method.Although the two methods recover ε from different field experiments and data,the difference of meanvalues is 0.0009.The first method is superior to the indirect method,and is also more convenient.  相似文献   

基于核磁共振测井资料构建水谱库的流体性质识别方法     

王艳  李庆峰  王慧  高慧波  孙建孟 《世界地质(英文版)》2014,(3)

以海拉尔地区为例,提出了基于核磁共振T2谱构建水谱库进行流体性质识别的一种新方法,实测核磁谱包含了孔隙结构、水和油气的信息,构建的水谱来自于水层的核磁实测谱,相当于消除了油气的影响,其基本原理是应用构建的水谱库与实测谱的差异识别流体性质。通过在海拉尔地区应用,得到了较好的应用效果。  相似文献   

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崔庆谷  杨星  杨跃文 《大地测量与地球动力学》2014,34(4):175-178

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Wave characteristics at the south part of the radial sand ridges of the Southern Yellow Sea     

杨斌  冯卫兵  张俞 《中国海洋工程》2014,28(3):317-330

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