基于最大连通面积直方图的图像检索算法研究

基于内容的图像检索中,颜色特征已得到广泛应用.传统颜色直方图检索方法不能体现图像空间信息,提出并实现了一种改进方法.进一步分析了具有相关颜色的像素之间在空间分布上的差异,用其在图像中形成的最大连通区域面积代替传统直方图中使用的数量总和指标,从而能够间接反映色彩的空间分布特征,提高检索质量,并保持了颜色直方图原有的旋转、平移不变性.     

多体互作用对13-原子团簇相变特性的影响

采用M.I.Baskes的Lennard-Jones Embedded-Atom(LJ-EMA)势作为原子之间的互作用,结合常能分子动力学模拟,计算了13-原子团簇的热曲线、方均根键长起伏、比热、动能的短时平均、位移平方的平均、其它12个原子相对于中心原子的角分布函数,着重地计算了相变区域的情形,对团簇融化-凝固相变特性进行了较为详细的研究,得出多体作用力的大小增加、范围减小导致融化温度(动能)的降低和共存区域范围变小的结论;证实了在一定的总能范围内类固(solidlike)和类液(liquidlike)两类特性团簇的共存;进一步明确了两步过程(表面融化)的成因;观察到在三种较大多体互作用范围势的情况下,出现负比热;进一步揭示了热曲线斜率、方均根键长起伏、比热和动能的短时平均分布之间的关联。     

Recent temperature increase recorded in an ice core in the source region of Yangtze River

Interests on climate change in the source region of Yangtze River have been raised since it is a region with the greatest warming over the Tibetan Plateau (TP). A 70-year history of precipitation δ~(18)O has been recovered using an ice core record retrieved in a plat portion of the firn area in the Guoqu Glacier (33°34′37.8″N, 91°10′35.3″E, 5720 m a.s.l.), Mt. Geladaindong (the source region of Yangtze River), in November, 2005. By using a significant positive relationship between ice core δ~(18)O record and summer air temperature (July to September) from the nearby meteorological stations, a history of summer air temperature has been reconstructed for the last 70 years. Summer temperature was relatively low in 1940s and high in 1950s to the middle of 1960s. The lowest temperature occurred in the middle of 1970s. Temperature was low in 1980s and dramatically increased since 1990s, keeping the trend to the begin-ning of the 21st century. The warming rate recorded in the ice core with 0.5℃/10 a since 1970s is much higher that that in the central TP and the Northern Hemisphere (NH), and it becomes 1.1℃/10 a since 1990s which is also higher than these from the central TP and the NH, reflecting an accelerated warm-ing and a more sensitive response to global warming in the high elevation region.     

关于运算放大器工作区域的分析

简述了理想运算放大器的模型和特点,根据集成运算放大器的工作区域,提出了运放工作状态的判断方法。     

基础域方法生成三维彩色对称伪球

用动力系统的方法自动生成对称的三维彩色球体。庞加来变换把过球心的单位圆盘映射到单位球面上,再把球面上的点映射到基础域,用动力系统迭代的方法确定其颜色。由于连续性,得到的彩球具有连续的的彩纹对称结构。     

我国西部生态补偿立法构想

介绍了我国西部生态补偿立法的迫切性,探讨了西部生态补偿法律渊源及其现状,论述了西部生态补偿立法的指导思想与基本原则,提出了西部生态补偿的立法构想。     

太原旅游区位特点及气候因素分析

太原是一座具有2500年历史的古城，历史文化遗产众多，旅游资源丰富，但许多旅游资源还没有转化为旅游产品。太原市的旅游发展具有特殊的区位优势，主要表现在：可开发的客源市场充足；基础设施和环境条件日臻完善；地处山西省疆土的中央，以太原为中心2h-3h路程的“大太原”旅游格局逐渐形成，太原又位于北京与西安两大国际旅游城市连接线的中点，形成北京-山西-陕西旅游黄金通道，太原气候条件优越，文章利用温湿指数和风效指数计算分析了太原全年旅游气候舒适度，得到结论：可以开展旅游的天数可达270d，适宜旅游天数210d，适宜于旅游、休闲、渡假、疗养天数为180d。     

RHIC能区π介子分布特征研究

利用相对论纵向非均匀集体膨胀流模型讨论RHIC能区的π介子分布,发现用此模型无法拟合π介子分布.作为改进,分别引入射弹和靶碎裂区的发射源,将π介子分布看成为射弹发射源、靶发射源和中心集体流3者贡献之和,以此理论得到的π介子分布与实验结果能较好地符合.     

黄河灌区水热通量的观测与分析

为解决农田节水问题,进行了田间水热通量观测和水热耦合循环过程机理分析。观测系统主要包括:常规气象、辐射、涡度相关法观测系统以及土壤水分观测剖面。该系统能够连续和稳定地观测土壤-植物-大气连续体中的水热循环过程,涡度相关法观测数据具有与国际同类观测一致的精度。对2005年山东省位山引黄灌区冬小麦和夏玉米生长期内水热平衡的分析表明:当叶面积指数较大时潜热是农田能量消耗的主要方式;在冬小麦返青至收割期内作物耗水略小于供水,而在玉米生长期内供水远大于作物耗水,灌区供水充分。     

Vegetation Spatial Heterogeneity of Different Soil Regions in Inner Mongolia, China

The vegetation spatial heterogeneity and ecological characteristics in different soil regions were analyzed by surveying the vegetation in 12 different soil regions of Inner Mongolia, China, including conifer- ous-broadleaf deciduous forests, shrub, grassland, and desert regions with 1122 large 2 cm × 2 cm quad- rats (actual size 30 km × 30 km, referred to as L-quadrat hereafter) in about 1.18 million km2. Each L- quadrat was divided into four small 1 cm × 1 cm quadrats (actual size 15 km × 15 km, S-quadrat). The vegetation was analyzed based on the beta-binomial distribution to describe the frequency of occurrence and spatial heterogeneity for each kind of vegetation. The weighted average of the heterogeneity of all vegeta- tion in the same soil region provides a measure of the soil regional landscape level heterogeneity which de- scribes the spatial complexity of the regional landscape composition of the existing vegetation. Comparison of the vegetation characteristics in the 12 soil regions shows that, the calcic gray soil has the highest average vegetation type per quadrat. The largest soil region is calcic chestnut soil and has the most vegetation types. Every soil region has its own dominant vegetation sequence which dominates in occurrence and dominant vegetation types which dominates in spatial heterogeneity. For the Inner Mongolian vegetation, the weighted average of the heterogeneity is 0.60 and the vegetation diversity index is 4.47.