S盒的互相关测试算法设计   总被引：1，自引：0，他引：1  

高胜  马文平  郭娜  陈秋丽 《武汉大学学报(信息科学版)》2010,(5)

S盒是构成分组密码算法重要的非线性部件,其密码学性质直接影响整个密码算法的安全性,因此对S盒的安全性检测十分重要。以往对S盒的安全性评估大多数集中在检测分量函数的安全性上,本文考虑了分量函数之间的关系,并利用Shannon在对称密码系统设计中所提出的混淆和扩散的思想,提出了S盒的互相关测试指标,设计了测试算法,更好地评价了S盒的安全性能。对DES和AES的S盒分别进行了实验,给出了测试结果。  相似文献   

性类固醇激素及其受体在半滑舌鳎性腺分化发育过程中的表达与生理功能     

徐永江  柳学周  温海深  王清印  马学坤  倪娜  赵明 《中国海洋大学学报(自然科学版)》2010,40(7)

首次用17β-雌二醇(E_2)及其受体(ERα)、睾酮受体(AR)的多克隆抗体在半滑舌鳎(Cynoglossus semilaevisG(u|¨)nther)性腺分化发育过程中进行免疫细胞化学定位研究。结果表明:在半滑舌鳎原始性腺中已有E_2、ERα和AR的分布和表达;卵原细胞、初级卵母细胞、精原细胞、初级精母细胞、次级精母细胞对E_2及ERα、AR抗体均呈现不同程度的阳性反应,在精细胞和精子中对E_2和ERα呈免疫阴性反应,而AR则一直保持较强表达,揭示了半滑舌鳎性腺中类固醇激素可能通过旁分泌调控机制刺激卵子和精子发育和成熟。性类固醇激素及其受体免疫阳性物定位在生殖细胞的胞质、胞膜和核膜等广泛部位并有表达,在性腺分化和不同发育时期的表达强度有所不同,表明其在性腺分化发育过程各阶段所起生理功能不同。这些结果为证明性类固醇激素及受体参与调节半滑舌鳎性腺分化发育提供了重要形态学新证据。  相似文献   

GPS网平面坐标系统转换及精度分析   总被引：1，自引：0，他引：1  

李娜  余学祥  高桂棠  杜贻晶 《测绘信息与工程》2010,35(1):6-7

建立了GPS网平面坐标系统转换模型，研究了其内部符合精度和外部检核精度，实现了高精度的坐标转换。  相似文献   

基于多源遥感数据的玛纳斯河流域荒漠化监测     

刘艳  丁涛  阮惠华  林娜 《国土资源遥感》2010,21(1):81-84

利用遥感手段对玛纳斯河流域绿洲-荒漠带的荒漠化状况进行监测。利用不同时期TM数据,在小尺度上分析该区域2000~2008年荒漠化土地的分布特征;基于MODIS陆地遥感产品(NDVI、Albedo及LST),利用多源信息复合法计算荒漠化程度指数;基于TM荒漠化监测结果对该指数进行分级处理,初步建立并验证基于MODIS数据的荒漠化监测评价模型。结果表明:近10 a来,绿洲外围荒漠化土地变化较小,大部分变化发生在绿洲内部,主要为局部荒漠化被开发或因盐碱化过重导致的撂荒;荒漠化监测评价模型对研究区荒漠化程度定量评价精度可达91.25%。  相似文献   

人类活动和气候变化对艾比湖湖泊面积的影响   总被引：6，自引：0，他引：6  

周驰  何隆华  杨娜 《海洋地质与第四纪地质》2010,(2)

新疆艾比湖地处我国西北干旱区,为典型的内陆封闭性湖泊,由于受内陆极端干旱气候及人类活动的影响,导致湖泊面积显著变化。湖泊面积变化所导致的生态环境恶化已成为制约当地社会经济发展的重要因素。以不同年份的多源遥感数据为数据源,分析了1972—2008年湖泊面积变化情况,并分析了特征年内湖泊面积变化的原因。认为气候要素中降水对湖泊面积影响较大,另外,人类活动引起绿洲变化,而绿洲农业灌溉用水对湖泊面积变化影响较大。同时,还分析了湖泊萎缩引起的湖泊水质恶化以及湖滨植被退化和区域沙漠化等环境效应,结果表明,湖泊面积是流域生态保障的重要指标,可作为反应湖泊流域生态情况的重要指标。由此提出了保护艾比湖生态环境的若干建议。  相似文献   

FY-3E: The First Operational Meteorological Satellite Mission in an Early Morning Orbit     

Peng ZHANG  Xiuqing HU  Qifeng LU  Aijun ZHU  Manyun LIN  Ling SUN  Lin CHEN  Na XU 《大气科学进展》2022,39(1):1-1

Fengyun-3 E(FY-3E),the world’s first early-morning-orbit meteorological satellite for civil use,was launched successfully at the Jiuquan Satellite Launch Center on 5 July 2021.The FY-3E satellite will fill the vacancy of the global early-morning-orbit satellite observation,working together with the FY-3C and FY-3D satellites to achieve the data coverage of early morning,morning,and afternoon orbits.The combination of these three satellites will provide global data coverage for numerical weather prediction(NWP)at 6-hour intervals,effectively improving the accuracy and time efficiency of global NWP,which is of great significance to perfect the global earth observing system.In this article,the background and meteorological requirements for the early-morning-orbit satellite are reviewed,and the specifications of the FY-3E satellite,as well as the characteristics of the onboard instrumentation for earth observations,are also introduced.In addition,the ground segment and the retrieved geophysical products are also presented.It is believed that the NWP communities will significantly benefit from an optimal temporal distribution of observations provided by the early morning,mid-morning,and afternoon satellite missions.Further benefits are expected in numerous applications such as the monitoring of severe weather/climate events,the development of improved sampling designs of the diurnal cycle for accurate climate data records,more efficient monitoring of air quality by thermal infrared remote sensing,and the quasicontinuous monitoring of the sun for space weather and climate.  相似文献   

非线性共轭梯度法在东海黑潮流计算中的应用   总被引：4，自引：0，他引：4  

陈红霞  袁业立  刘娜  曲媛媛 《海洋学报》2003,25(6):31-38

基于现有的几种海流计算方法,根据与P矢量法相同的动力特性和内在假设,对海流计算提出了一种简单、高效、易扩展、适用范围广的新方法:非线性共轭梯度法.利用1989年4月以来的"中日黑潮合作调查研究"6个航次的CTD资料,对东海黑潮流区域应用非线性共轭梯度法进行了海流计算.通过与船载ADCP实测结果比较表明,非线性共轭梯度法是可行的.  相似文献   

流场散度的误差估计     

麻娜 《海洋科学》2006,30(8):13-16

按照误差传递原理,推导出流场散度的误差估计式,并将其应用于赤道中东太平洋上升流区域水平散度误差的估计。应用结果表明:赤道中东太平洋上升流区多年平均流场的散度稳定,平均散度约为3.0×10-7s-1;和通常采用的误差估计公式相比,该估计公式降低了散度误差,从而提高了散度的可信度。  相似文献   

Development and characterization of a cell line from the embryos of half smooth tongue sole (Cynoglossus semilaevis)   总被引：2，自引：1，他引：2  

SHA Zhenxi  REN Guocheng  WANG Xianli  WANG N  CHEN Songlin 《海洋学报(英文版)》2010,29(2):81-87

A new cell line,CSEC,has been successfully established from embryos at gastrula stage of a cultured marine fish,half smooth tongue sole(Cynoglossus semilaevis).CSEC cells grow actively and stably more than 50 passages for over 200 d in DMEM medium supplemented with 15% FBS(fetal bovine serum),2.5 ng/cm 3 bFGF(basic fibroblast growth factor),1 ng/cm 3 LIF(leukemia inhibitory factor) and 50 mmol/dm 3 2-ME(2-mecaptoethanol).The cells grew well in the temperature range of 24-30 ℃ and the optimal growth temperature was 24℃.FBS and bFGF concentrations are the two key components for CSEC cells proliferation.Chromosome analysis reveals that CSEC cells have a normal diploid karyotype with 2n=42t.The significant fluorescent signals were observed in CSEC after transfection with the GFP reporter gene,suggesting that the CSEC cell line can be used as a useful tool for transgenic and genetic manipulation studies.CSEC cells showed the cytopathic effect(CPE) after infection with lymphosystis disease virus(LCDV) in 2 d.Moreover,the LCDV particles can be observed in the cytoplasm of virus-infected cells by electron microscopy.It suggests that CSEC could be potentially used for the study of aquatic virus.  相似文献   

Variation in Water Masses on Shelf of Northern Bering Sea in September 2016-2018     

Yingjie Wang  Na Liu  Lina Lin  Yan He  Bin Kong  Zhanhai Zhang 《Marine Geodesy》2020,43(3):285-301

Abstract

Based on hydrological data obtained during the 7th to 9th Chinese National Arctic Research Expeditions in the summers of 2016–2018, the main water structure on the shelf of the northern Bering Sea and the volume and heat fluxes of the Bering Strait throughflow were analyzed. Distinct variability was identified in the three Pacific water masses feeding the strait - Anadyr Water (AW), Bering Shelf Water (BSW) and Alaskan coastal water (ACW). Overall, the temperature and salinity of the entire section increased each year, with 2018 showing significant anomalies, i.e., a temperature anomaly of up to 1?°C and a maximum salinity anomaly of 2. From 2016 to 2018, the extent of the ACW gradually narrowed in the eastern part of this section, while the AW expanded eastward each year. The net volume transport through each of the three sections increased poleward from 1.65?Sv to 2.76?Sv, with the AW increasing from 0?Sv to 1.03?Sv, the BSW varying between 0.52–1.65?Sv, and the ACW gradually decreasing from 1.04?Sv to disappearing completely. The net heat fluxes were also poleward, varying between 25.77 TW and 61.50 TW, and showing a significant increase. Significant variations in magnitude and extent were observed in each water mass of the Bering Strait throughflow, which could produce widespread effects in the Arctic Ocean and the global ocean beyond.  相似文献