辽宁省中部城市群居民地的分布格局

根据2006年Landsat TM影像,利用Erdas和ArcGIS软件,结合区划理论和聚落地理学,对辽宁省中部城市群的居民地分布格局进行了研究。结果表明:1)辽宁省中部城市群居民地在斑块数量上主要以小型斑块为主,斑块面积<1km2的斑块数量达斑块总数的96.38%,在斑块面积上以沈阳等几个大型城市的居民地占主要地位。2)依据居民地面积的空间比重将辽宁省中部城市群居民地划分为东部地区、沈阳地区和西部地区3个特征区域,其中沈阳地区平均斑块面积最大,城市化程度最高;西部地区斑块密度最大,居民地最为密集;东部地区平均斑块面积和斑块密度均最小,居民地发育程度低于另2个区域。3)尽管居民地在3个区域内都呈随机分布,但其指示参数——最邻近点指数还是体现出明显的区划差异。4)居民地分布受中心城市的影响显著,各中心城市的辐射范围不同,大小依次为沈阳>鞍山>铁岭>营口>辽阳>本溪>抚顺。

基于RS的黄河中游多沙粗沙区土地利用变化分析

据1975年的Landsat MSS、1986年和1997年的Landsat TM影像资料,运用遥感影像计算机自动分类方法获取土地利用信息,用GIS空间分析方法以及数理统计方法全面分析了黄河中游多沙粗沙区1975~1986年和1986~1997年两个时期内各土地利用类型的变化幅度、变化速度、数量变化的区域差异、变化方向以及变化方向的区域差异等。结果表明:后期土地利用类型间的相互转化有所增强;耕地、草地、林地和未利用地是本区土地利用变化的主导类型,耕地、草地与其它土地利用类型间的相互转化分布校广;后期耕地被居民地占用的面积和毁林开荒的面积比前期有所增加。

China's changing landscape during the 1990s: Large-scale land transformations estimated with satellite data

Land-cover changes in China are being powered by demand for food for its growing population and by the nation's transition from a largely rural society to one in which more than half of its people are expected to live in cities within two decades. Here we use an analysis of remotely sensed data gathered between 1990 and 2000, to map the magnitude and pattern of changes such as the conversion of grasslands and forests to croplands and the loss of croplands to urban expansion. With high-resolution ( 30 m) imagery from Landsat TM for the entire country, we show that between 1990 and 2000 the cropland area increased by 2.99 million hectares and urban areas increased by 0.82 million hectares. In northern China, large areas of woodlands, grasslands and wetlands were converted to croplands, while in southern China large areas of croplands were converted to urban areas. The land-cover products presented here give the Chinese government and international community, for the first time, an unambiguous understanding of the degree to which the nation's landscape is being altered. Documentation of these changes in a reliable and spatially explicit way forms the foundation for management of China's environment over the coming decades.

Land-cover classification of China: integrated analysis of AVHRR imagery and geophysical data

Over last two decades, numerous studies have used remotely sensed data from the Advanced Very High Resolution Radiometer (AVHRR) sensors to map land use and land cover at large spatial scales, but achieved only limited success. In this paper, we employed an approach that combines both AVHRR images and geophysical datasets (e.g. climate, elevation). Three geophysical datasets are used in this study: annual mean temperature, annual precipitation, and elevation. We first divide China into nine bio-climatic regions, using the long-term mean climate data. For each of nine regions, the three geophysical data layers are stacked together with AVHRR data and AVHRR-derived vegetation index (Normalized Difference Vegetation Index) data, and the resultant multi-source datasets were then analysed to generate land-cover maps for individual regions, using supervised classification algorithms. The nine land-cover maps for individual regions were assembled together for China. The existing land-cover dataset derived from Landsat Thematic Mapper (TM) images was used to assess the accuracy of the classification that is based on AVHRR and geophysical data. Accuracy of individual regions varies from 73% to 89%, with an overall accuracy of 81% for China. The results showed that the methodology used in this study is, in general, feasible for large-scale land-cover mapping in China.

Landscape change detection of the newly created wetland in Yellow River Delta

Four models are employed in the landscape change detection of the newly created wetland. The models include ones for patch connectivity. ecological diversity, human impact intensity and mean center of land cover. The landscape data of the newly created wetland in Yellow River Delta in 1984, 1991, and 1996 are produced from the unsupervised classification and the supervised classification on the basis of integrating Landsat TM images of the newly created wetland in the four seasons of the each year. The result from operating the models into the data shows that the newly created wetland landscape in Yellow River Delta had a great chance. The driving focus of the change are mainly from natural evolution of the newly created wetland and rapid population growth, especially non-peasant population growth in Yellow River Delta because a considerable amount of oil and gas fields have been found in the Yellow River Delta. For preventing the newly created wetland from more destruction and conserving benign Succession of the ecosystems in the newly created wetland, six measures are suggested on the basis of research results. (C) 2003 Elsevier Science B.V. All rights reserved.

Study on spatial pattern of land-use change in China during 1995-2000

It is more and more acknowledged that land-use/cover dynamic change has become a key subject urgently to be dealt with in the study of global environmental change. Supported by the Landsat TM digital images, spatial patterns and temporal variation of land-use change during 1995 -2000 are studied in the paper. According to the land-use dynamic degree model, supported by the 1km GRID data of land-use change and the comprehensive characters of physical, economic and social features, a dynamic regionalization of land-use change is designed to disclose the spatial pattern of land-use change processes. Generally speaking, in the traditional agricultural zones, e.g., Huang-Huai-Hai Plains, Yangtze River Delta and Sichuan Basin, the built-up and residential areas occupy a great proportion of arable land, and in the interlock area of farming and pasturing of northern China and the oases agricultural zones, the reclamation I of arable land is conspicuously driven by changes of production conditions, economic benefits and climatic conditions. The implementation of "returning arable land into woodland or grassland" policies has won initial success in some areas, but it is too early to say that the trend of deforestation has been effectively reversed across China. In this paper, the division of dynamic regionalization of land-use change is designed, for the sake of revealing the temporal and spatial features of land-use change and laying the foundation for the study of regional scale land-use changes. Moreover, an integrated study, including studies of spatial pattern and temporal process of land-use change, is carried out in this paper, which is an interesting try on the comparative studies of spatial pattern on change process and the change process of spatial pattern of land-use change.

Industrial development and land use/cover change and their effects on local environment: a case study of Changshu in eastern coastal China

The interactions among industrial development, land use/cover change (LUCC), and environmental effects in Changshu in the eastern coastal China were analyzed using high-resolution Landsat TM data in 1990, 1995, 2000, and 2006, socio-economic data and water environmental quality monitoring data from research institutes and governmental departments. Three phases of industrial development in Changshu were examined (i.e., the three periods of 1990 to 1995, 1995 to 2000, and 2000 to 2006). Besides industrial development and rapid urbanization, land use/cover in Changshu had changed drastically from 1990 to 2006. This change was characterized by major replacements of farmland by urban and rural settlements, artificial ponds, forested and constructed land. Industrialization, urbanization, agricultural structure adjustment, and rural housing construction were the major socio-economic driving forces of LUCC in Changshu. In addition, the annual value of ecosystem services in Changshu decreased slightly during 1990-2000, but increased significantly during 2000-2006. Nevertheless, the local environmental quality in Changshu, especially in rural areas, has not yet been improved significantly. Thus, this paper suggests an increased attention to fully realize the role of land supply in adjustment of environment-friendly industrial structure and urban-rural spatial restructuring, and translating the land management and environmental protection policies into an optimized industrial distribution and land-use pattern.

黑白仰鼻猴（Rhinopithecus bieti）西藏种群栖息地变化研究

黑白仰鼻猴（Rhinopithecus bieti）目前分布在金沙江和澜沧江之间横断山脉的一个狭小的区域范围内（26o14’N-29o20’N，99o15’E-99o37’E），海拔2 600 m（南部） - 4 200 m（北部）之间；目前大约有15 群，数量估计约1700 个体。是我国特有的灵长类之一，为国家Ⅰ级保护动物，在IUCN（世界自然保护联盟）2007 受威胁物种红皮书中被列为濒危物种并处于小种群、高度片断化状态（ENC 2a）。西藏是黑白仰鼻猴分布的北端，约有300 个体。基于前人的野外调查和报道确认，暗针叶林和针阔叶混交林是其适宜栖息地，人们在低海拔和高海拔砍伐或者火烧暗针叶林和针阔叶混交林的产物－农田和夏季牧场正在逐渐侵蚀着其适宜栖息地。尽管当地藏族村民信奉佛教，禁止猎杀任何野生动物，但是近些年来，黑白仰鼻猴栖息地不断丧失，这与牧场和农田扩张、当地人们薪柴采集等活动有关。黑白仰鼻猴西藏种群主要在原始暗针叶林和和针阔叶混交林里活动。为了评估该物种的栖息地现状和变化情况，我们通过野外调查工作，应用GIS 和RS 技术，分别解译了1986 年、1992 年、1997 年、2001 年和2006 年的Landsat TM/ETM+ 冬季卫星影像，并对解译结果进行了计算和分析，得到了以下西藏种群栖息地的主要结果： 1）现有暗针叶林（包括原始针叶林和针阔混交林）面积是30 500 hm2 ，夏季牧场面积是13 100 hm2 ，农田面积是6 400 hm2 ；2）在过去20 年间（1986-2006 年），暗针叶林面积减少了14.6％（5 200 hm2 ），夏季牧场面积增加了47.2％（4 200 hm2 ），农田面积增加了14.3％（800 hm2 ）；3）在过去20 年间，暗针叶林的斑块数量增加了68.4％，平均斑块面积下降了49.3％（从1986 年的15.1 hm2 下降到2006 年的7.6 hm2 ），最大的斑块指数下降了54.9％；景观丰富度并没有变化，但Shannon 多样性指数和Shannon 均匀度指数分别增加了2.7％。这都表明栖息地丧失和破碎化程度越来越严重。在上述结果的基础上，我们进一步对栖息地变化的主要原因进行了初步分析和探讨。通过暗针叶林面积、夏季牧场面积和农田面积和当地各乡村的家庭户数、人口数量、平均家庭人口数和牲畜存栏数等统计数据的Spearman秩相关分析表明，暗针叶林面积变化分别与当地的人口数量、家庭户数和平均家庭人口数呈显著负相关，与牲畜存栏数呈负相关；而夏季牧场面积和农田面积都分别与人口数量、家庭户数和平均家庭人口数呈显著正相关，与牲畜存栏数呈正相关。这意味着在目前当地传统生产方式基本未发生改变的情况下，因人口数量增加所带来的生产等活动强度的增加是黑白仰鼻猴栖息地丧失与破碎化加剧的主要原因（R2 = 0.972）；当地人类经济活动的增加，如牧场和农田扩张，牲畜存栏数增加以及薪材采集和木质建筑等导致了栖息地丧失、退化和破碎化。但另一方面，当地一妻多夫的婚配制度（仅在西藏部分地区仍有保留）对黑白仰鼻猴的栖息地保护有积极的作用，因为大家庭（家庭人口数）的人均资源消耗，如薪柴需求、房屋数量、牧场和农田等，都比小家庭低。在过去20 年中（1983-2003 年），当地家庭户数的增加比人口数量增加要慢，这对黑白仰鼻猴的栖息地保护起到了一定的积极作用。因此，西藏种群作为单独的遗传亚种群，其保护工作任重而道远。

Synthesis and Luminescent Properties of LaAlO3:RE3+ (RE = Tm, Tb) Nanocrystalline Phosphors via a Sol-Gel Process

LaAlO3:Tm3+ and LaAlO3:Tb3+ phosphors were prepared through a Pechini-type sol-gel process. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), photoluminescence, and cathodoluminescence (CL) spectra were utilized to characterize the synthesized phosphors. The XRD results reveal that the fully crystalline pure LaAlO3 Phase can be obtained at 800 degrees C. The FE-SEM image indicates that the phosphor samples are composed of aggregated spherical particles with sizes ranging from 40 to 80 nm. Under the excitation of ultraviolet light (230 nm) and low-voltage electron beams (1-3 kV), the LaAlO3:Tm3+ and LaAlO3:Tb3+ phosphors show the characteristic emissions of Tb3+ (D-1(2)-> H-3(6,4),F-3(4) transitions) and Tm3+ (D-5(3,4)-> F-7(6,5,4,3) transitions) respectively. The CL of the LaAlO3:Tm3+ phosphors have high color purity and comparable intensity to the Y2SiO5:Ce3+ commercial product, and the CL colors of Tb3+-doped LaAlO3 phosphors can be tuned from blue to green by changing the doping concentration of Tb3+ to some extent.

Self-assembled 3D flowerlike Lu2O3 and Lu2O3 : Ln(3+) (Ln = Eu, Tb, Dy, Pr, Sm, Er, Ho, Tm) microarchitectures: Ethylene glycol-mediated hydrothermal synthesis and luminescent properties

Three-dimensional flowerlike Lu2O3 and Lu2O3:Ln(3+) (Ln = Eu, Th, Dy, Pr, Sm, Er, Ho, Tm) microarchitectures have been successfully synthesized via ethylene glycol (EG)-mediated hydrothermal method followed by a subsequent heat treatment process. X-ray diffraction, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectra, thermogravimetric and differential thermal analysis, elemental analysis, inductively coupled plasma atomic absorption spectrometric analysis, ion chromatogram analysis, X-ray photoelectron spectra, scanning electron microscopy, transmission electron microscopy, photoluminescence spectra as well kinetic decays, and cathodoluminescence spectra were used to characterize the samples. Hydrothermal temperature, EG, and CH3COONa play critical roles in the formation of the lutetium oxide precursor microflowers. The reaction mechanism and the self-assembly evolution process have been proposed. The as-formed lutetium oxide precursor could transform to Lu2O3 With their original flowerlike morphology and slight shrinkage in the size after postannealing process.

Four New Lanthanide-Nitronyl Nitroxide (Ln(III)=Pr-III, Sm-III, Eu-III, Tm-III) Complexes and a Tb-III Complex Exhibiting Single-Molecule Magnet Behavior

Five new complexes based on rare-earth-radical [Ln(hfac)(3)(NIT-5-Br-3py)](2) (Ln=Pr (1), Sm (2), Eu (3), Tb (4), Tm (5); hfac = hexafluoroacetylacetonate; NIT-5-Br-3py = 2-(4,4,5,5-tetramethyl-3-oxylimidazoline-1-oxide)-5-bromo-3-pyridine) have been synthesized and characterized by X-ray crystal diffraction. The single-crystal structures show that these complexes have similar structures, in which a NIT-5-Br-3py molecule acts as a bridging ligand linking two Ln(III) ions through the oxygen atom of the N-O group and nitrogen atom from the pyridine ring to form a four-spin system. Both static and dynamic magnetic properties were measured for complex 4, which exhibits single-molecule magnetism behavior.

Highly uniform and monodisperse beta-NaYF4 : Ln(3+) (Ln = Eu, Tb, Yb/Er, and Yb/Tm) hexagonal microprism crystals: Hydrothermal synthesis and luminescent properties

beta-NaYF4:Ln(3+) (Ln = Eu, Tb, Yb/Er, and Yb/Tm) hexagonal microprisms with remarkably uniform morphology and size have been synthesized via a facile hydrothermal route. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and photoluminescence (PL) spectra as well as kinetic decays were used to characterize the samples. It is found that sodium citrate as a shape modifier introduced into the reaction system plays a critical role in the shape evolution of the final products. Furthermore, the shape and size of the products can be further manipulated by adjusting the molar ratio of citrate/RE3+ (RE represents the total amount of Y3+ and the doped rare earth elements such as Eu3+, Tb3+, Yb3+/Er3+, or Yb3+/Tm3+). Under the excitation of 397 nm ultraviolet light, NaYF4:xEu(3+) (x = 1.5, 5%) shows the emission lines of Eu3+ corresponding to D-5(0-3) -> F-7(J) (J = 0-4) transitions from 400 to 700 nm (whole visible spectral region) with different intensity, resulting in yellow and red down-conversion (DC) light emissions, respectively.

Thermoluminescence studies of LiBa2B5O10 : RE3+ (RE = Dy, Tb and Tm)

LiBa2B5O10:RE3+ (RE = Dy, Tb and Tm) was synthesized by the method of high-temperature solid-state reaction and the thermoluminescence (TL) properties of the samples under the irradiation of the gamma-ray were studied. The result showed that Dy3+ ion was the most efficient activator. When the concentration of Dy3+ was 2 mol%, LiBa2B5O10:Dy3+ exhibited a maximum TL output. The kinetic parameter of LiBa2B5O10:0.02Dy was estimated by the peak shape method, for which the average activation energy was 0.757 eV and the frequency factor was 1.50 x 10(7) s(-1). By the three-dimensional (3D) TL spectrum, the TL of the sample was contributed to the characteristic f-f transition of DY3+. The dose-response of LiBa2B5O10:0.02Dy to gamma-ray was linear in the range from 1 to 1000 mGy. In addition, the decay of the TL intensity of LiBa2B5O10:0.02Dy was also investigated.

Preparation of borates doped with divalent rare earth ions (RE2+) in air and spectroscopy of divalent rare earth ions (RE2+ = Sm, Eu, Tm, Yb)

The spectroscopic feature of divalent Sm2+, Eu2+, Tm2+ and Yb2+ is discussed in this paper. Especially the spectroscopic properties of some berates containing tetrahedral BO4 group such as SrB4O7, SrB6O10 and BaB8O13 doped with these divalent ions are reported. When the divalent alkaline earth ion in these berates is replaced partially by the above trivalent rare earth ion, the charge carried in the produced defects can be used as reductant to reduce the doped rare earth ion into divalent state at high temperature even in air. Therefore, a convenient and safe method is provided to prepared phosphors doped with these divalent rare earths.