我国林业地理信息产业发展与创新

林业地理信息,是以森林资源及生态环境为研究对象,依托现代地球观测、大数据、物联网、云计算等先进技术,通过精准的时空观测,实施精准的时空作业,达到理想林业时空模式,从而使森林最大限度地发挥生态效益、社会效益和经济效益。林业地理信息主要应用在森林观测、森林经营、造林、森林灾害防控方面。本文从林业地理信息特征、林业地理信息产业需求和林业地理信息装备创新3个方面对林业地理信息进行阐述。     

应用三次样条法进行林地面积量算的研究

本文通过对各种面积量算方法的比较研究,提出了各种量算方法的优缺点和适应性。比较了仪器实测与图上量测林地面积精度之间的关系,得出图上量测林地面积因不可避免的存在系统误差而其精度要比仪器实测林地面积所得精度要低的结论。最后本文着重推导了利用三次样条法测定林地面积的数学原理,并对梯形公式法、辛普生法、等距三次样条法和三次样条法对于林地面积边界不规则曲线的拟合原理进行了分析比较,结合对中国科协北京绿化基地地块同精度的GPS测量试验结果运用上述四种方法量算面积的精度结果进行比较,可知三次样条法量算林地面积的精度最高,且该方法便于差分GPS(RTDGPS)作业。     

Polycyclic musks in green-lipped mussels (Perna viridis) from Hong Kong

Six polycyclic musk compounds [Cashmeran (DPMI), Celestolide (ADBI), Phantolide (AHMI), Traseolide (ATII), Tonalide (AHTN), and Galaxolide (HHCB)] were analysed in marine green-lipped mussels (Perna viridis) from Hong Kong. ADBI, HHCB and AHTN were detected in almost all samples, while AHMI, ATII and DPMI were not detected. Concentrations of ADBI, HHCB and AHTN in mussels ranged from below detection limit-0.0743 (mean: 0.0246), 0.247-6.08 (mean: 1.15) and 0.0591-0.738 (mean: 0.190)mg/kg lipid weight, respectively. Mussels from two sampling sites in central Victoria Harbour contained the highest total polycyclic musk levels, suggesting that these waters are heavily influenced by domestic sewage. Concentrations of HHCB and AHTN detected in the mussel samples were the second highest and the highest levels, respectively, compared to global concentrations. A preliminary risk assessment indicated that HHCB and AHTN in mussels pose little or no threat to the health of shellfish consumers. Nevertheless, more comprehensive studies are required to further assess the ecological and human health risks associated with polycyclic musks.     

Poly-aromatic hydrocarbon (PAH) inputs from the Rhône River to the Mediterranean Sea in relation with the hydrological cycle: impact of floods

The concentrations of dissolved and particulate polycyclic aromatic hydrocarbons (PAHs) were monitored in waters of the Rhône River (France) every fortnight for a full calendar year, from June 1994 to May 1995. All flood events occurring over the course of the experiment were sampled at higher frequency to better quantify the impact of these extreme hydrological episodes on the annual export of PAHs to the Mediterranean Sea. This time-series indicates that more than 90% of the annual load of particulate PAHs is transported during flood episodes, with 77% discharged during the course of only one extreme flood event occurring in November 1994. During these intense events, riverine particles are depleted in PAHs while at low river discharge particles are PAH-enriched. Dissolved PAHs were less variable and less abundant than adsorbed PAHs, consistently with the low solubility of these compounds.     

Population and employment in selected countries bordering the Pacific

This study is concerned with the dynamics of labor force composition in selected countries bordering the Pacific. The estimates presented are based on national definitions of urban and rural places and of the labor force and are derived primarily from published U.N. data. Variations in labor force composition and in urbanization levels by country are discussed. Countries considered include Canada, Costa Rica, Ecuador, Japan, the Republic of Korea, Nicaragua, Peru, the Philippines, and the United States.     

全站仪三维导线测量定位系统

本文以全站仪为工具,以E500为控制器和采集器,以测量过程实时化、自动化为目标,建立了一种全站仪三维导线测量定位系统。系统可在任何条件下自动、实时、精密地确定点的三维坐标,并可进行坐标系统转化,自动在E500中建立数据文件,实现与微机和其它仪器通讯。     

联合国采用“储量／资源国际分类基础”

简述不久前联合国采用的“储量／资源国际分类基础”的主要内容,并指出将其应用有外国投资者参与的设计评价的可能性。