弱散射体的宽谱BRDF测量与分析

弱反射体粗糙表面具有复杂的散射现象.随着入射光天顶角的增加,这类弱反射体的光反射由方向性漫散射过渡到镜面反射,且波长不同的反射光出现不同强度的镜面反射.为了研究这个波动光学现象,使用一台宽谱全向反射计测量了两个弱反射体样品在多个可见波长的双向反射分布函数;使用一台探针式表面轮廓仪测量了样品的表面轮廓,进而获得了样品表面统计特性.一个基于波动光学的BRDF模型通过拟牛顿法优化算法逐次逼近被拟合到测量数据,准确地描述了散射光随角度和波长的变化.通过拟合结果和测量数据比较,证明基于波动光学的BRDF模型适用于解释该现象.     

二向反射模型在土地覆被制图中的应用

植被的反射异质性特征可以反映植被的结构和光谱特性,有助于更有效地识别植被.在塔里木河下游开展的研究中,使用了MISR的多角度观测数据,利用核驱动和RPV模型反演获取地表BRDF信息,使用SVM方法对MISR天底角反射率数据和BRDF信息组合进行土地覆被分类研究,对比分析了BRDF对分类效果的影响.发现:①BRDF信息可以为半干旱区土地覆被制图提供附加的有用信息,提高制图的精度.②核驱动模型和RPV模型都能较好地模拟研究区地表反射的状况.③空间结构差异较大的草地和林地类型使用BRDF信息后的用户精度明显提高.     

对地观测图像BRDF校准模型的建立与应用

为提高对地观测图像质量的数据校准方法,建立区别于传统模型的对地观测目标复合双向反射分布函数（BRDF） 模型. 通过BRDF量值实现计量标准对该模型进行绝对量值标定,使得对地观测影像更真实反映观察对象. 该模型综合考虑对地观测目标的BRDF分布、太阳辐射、大气分布状况等,加入BRDF国家计量标准的修正参量,结合遥感相机参数,得到计量校准后的遥感相机入瞳辐亮度数据. 以一种典型建筑材料毛玻璃的BRDF测量及其对地观测图像的校准为例,通过这一复合模型的校准,其图像的色差提高约3,亮度对比提高约3.      

天空散射光对地物反照率反演的影响分析

为了精确计算地物光谱反照率,通过对地气系统辐射传输模型的建立与分析,推导出了天空散射光的计算方法,给出了地物光谱反照率的理论计算公式.选用9种不同地物覆盖的POLDER二向性反射分布函数(BRDF)数据,分别计算了地物的方向-半球反照率(DHR)和双半球反照率(BHR),利用6S辐射传输模型按推导的公式计算天空散射光比例因子,并对这2种反照率进行耦合计算得到了地物光谱反照率.根据443,565,670,763和865nm这5个通道的9种地物光谱反照率的反演结果,各向同性天空光的假设造成的平均误差分别为0.296%,0.221%,0.157%,0.120%和0.103%.在实际应用中,建议使用理论推导公式作为地物光谱反照率的计算方法.     

再论BRDF互易原理的尺度效应

互易原理是电磁学、光学的常用原理之一,是辐射传输理论的基石.当这一理论被用到遥感研究中,相当多的测量数据,尤其是野外测量数据不支持互易原理在传感器像元尺度上的有效性,因而,互易原理被当作检验遥感数据质量标准时,受到测量界的强烈反对.李小文等用几何光学模型证明了互易原理的尺度效应(Progress in Natural Science,1998,8(3):354～358).Snyder对李等的证明提出质疑(Applied Optics,2002,41(21):4307～4313),并试图证明互易原理在遥感中适用的无条件性,文中对Snyder的质疑进行了考察,指出,由于作者忽略了李小文等证明二向反射(BRDF)互易原理尺度效应的重要条件,并不能证明互易原理是无条件适用于遥感目标的研究尺度的,并再度证明,BRDF互易原理存在尺度效应.     

多类目标样片BRDF三维统计建模及优化

在Torrence-Sparrow模型的基础上,修正和简化了五参数模型,对多类目标样片双站多角度双向反射分布函数(BRDF)测量数据进行了拟合,在二维情况下与五参数模型进行了比较,两者均与实验数据吻合,表明了五参数模型良好的适应性,能够对不同粗糙度,不同光学特性的材料进行拟合.优化过程采用遗传算法与退火算法相结合,具有把握全局和较快收敛速度的特点,对于问题的解决起到了关键作用.五参数模型是三维空间模型,通过对某些样片的多组多角度双站三维实验数据进行的拟合充分利用了三维空间信息,建立了BRDF空间分布图,进而获得粗糙表面的更多光散射信息.     

二向性归一化植被指数:概念及应用

最近发布的星载法国地表反射的极化与方向性观测仪(POILDER)与美国中分辨率成像光谱仪(MODIS)的地表二向性反射(BRDF)数据产品,其输入数据的大气纠正未能满足定量遥感的需求.提出了二向性归一化植被指数(BiNDVI)的概念,以同时考虑地表反射的二向性与大气程辐射的影响,并用于定义卫星多角度遥感观测值的大气质量指数.用该指数加权迭代反演,能明显改进MODIS-BRDF的数据产品质量.     

MOCVD Al_xGa_(1-x)N/GaN超晶格结构的界面与表面表征

采用掠入射X射线反射谱技术和原子力显微镜表面形貌技术对AlxGa1-xN/GaN超晶格结构的界面与表面进行了表征,将反射谱数据与X射线衍射结果结合获得了垒层组分及阱层宽度与界面粗糙度的关系.掠入射X射线反射谱的显著强度振荡与原子力显微镜所观察到的台阶流动形貌表明了平整的界面和表面的存在.研究发现,低Al组分(x=0.15)阱宽小的样品界面与表面粗糙度最小.     

朗伯假设对地表反照率的影响

为了研究地表朗伯假设对反照率遥感反演的影响作用,取各BRDF原型类作为地表反射各向异性的基本样式,将模拟方向反射率数据作为朗伯假设反照率,借助一景MODIS图像的BRDF/反照率产品,分析其与反照率在观测空间分布特征上的相对差异.结果表明:朗伯假设对地表反照率的影响与地表反射各向异性样式、太阳天顶角大小以及观测所在空间位置等密切相关.当地表反射各向异性特征较显著时,朗伯假设会在后向热点、前向冷点以及较大的观测天顶角附近向反照率中引入40%以上的误差,且随着太阳天顶角的增大,这一差异还会显著增加.此外,天顶方向反射率与反照率的差异同样与地表反射各向异性特征和太阳天顶角大小密切相关.当太阳天顶角较小时,几何光学散射作用较强的BRDF原型类会高估地表反照率;当太阳天顶角较大时,体散射作用较强的BRDF原型类会明显低估地表反照率.     

基于BRDF订正的兰州地区春季气溶胶光学厚度反演实验

利用6S模式反演并分析兰州地区春季气溶胶光学厚度(AOD)分布情况,探讨了双向反射分布(BRDF)对气溶胶光学厚度反演结果的影响.结果表明:兰州地区2010年春季气溶胶光学厚度高值中心位于西工业区和城关区,最大值分别为0.46和0.31.不考虑BRDF时水面上空气溶胶光学厚度反演结果存在明显误差,经Walthall BRDF订正后,水面上空误差明显减小,说明经过Walthall BRDF订正后的6S模式适用于水面上空的气溶胶光学厚度反演.兰州大学半干旱气候与环境观测站(SACOL)站点(35.57°N,104.08°E)反演值和实测值比较表明,在无云晴天条件下,选用Walthall BRDF模式可以提高AOD反演精度.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

The Analects and the Moment in Peking——The influence of a Confucian education system on the personality formation,the way of thinking and the fate of the main characters

0.Preface China has long been boasting of its colorful and immense culture which comprises of Taoism,Confucianism and Buddhism.The interwoven influence among the religions on Chinese way of thinking,on the nation＇s behavior in their social life throughout the long history is beyond list.