处理多波段数据课题中的主元素方法

<正> 1.减少测度的维数假设u~(i)=(u_(1i),u_(2i),…u_(ni))—为影像第i个因子的多波段测量值(在n个光谱段中的光谱亮度值),而n={u~((1)),u((2)),…u~((n))}—是对整个影像或它的局部量测值的总和。处理这些数据对下列各点是重要的。     

辐射松的隐座霉疫病

世界上人口不断增长,对植物资源,包括木材的需要不断增加,在满足人类木材要求方面,辐射松(Pinus radiata D.Don)起着重要的作用。辐射松每年每公顷生长量可高达24立方米,而且造林容易,成本低廉,是一个优良的造林树种。辐射松在原产地仅分布于加利福利亚滨海以及瓜德罗普沿岸岛屿大约4000余公顷的地区,而且形状和大小也并不出众。但在十九世纪后期引种到许多其它国家后,其生长一般比原产地好,智利、新西兰、澳大利亚和东非等国家和地区都采用它作为营造大面积商品林的树种。迄今为止,辐射松栽植最广的地区是智利和新西兰,这两个国家都有25万公顷以上的辐射松林,生产木材和发展造纸业。澳大利亚也有10万公顷以上的辐射松林,大部分     

Analysis of Sediment Source of Watershed in Western Shanxi of the Loess Plateau

1 INTRODUCTIONThe Loess Plateau is the most drastic soil erosion regionin China, with the most severe water erosion. Thedistribution of types and intensity of erosion not onlyhave regional diversity but also have perpendicularvariation. In the small watershed, there are differencesin erosion characters among its upper, middle and lowerreaches. It is very significant for taking rationalmeasures of soil and water conservation and forpreventing soil and water loss to analyze the relationbe…     

热带木材的干燥

一、大气干燥气干的优点是不用昂贵的设备.缺点是干燥时间长;必须库存大量木材因而影响资金周转;需要花工经常搬动;容易遭受菌虫害;气干的木材往往不能达到利用时的干燥要求等。 (一)气干场地的条件最好选择矿质土,潮湿的土壤排水良好和靠近江河均有利于菌类繁殖.场地应当设在车间或工厂附近,与车间之间应设有通     

Study on Balance between Supply and Demand for Timber and Timber Products in China

INTRODUCTION Because China is deficient in forest resources, and the forest has the characteristics of low quality, uneven distribution, slow growth and severe situation of ecological environment, the ecology construction has become the first requirement in society and with the implementation of the “Natural Forest Conservation Program”, Chinese forestry is in the historic transition from timber production to ecological construction. Therefore, the timber production in China increases…     

森林与环境

森林是加拿大最突出的风景。从大西洋到太平洋3,000哩广阔的土地上处处是森林。森林工业现在使用着多种多样的资源。每一年的造林面积是2.5百万亩。(1英亩=6.072市亩=0.447公顷—译者)森林不仅仅影响着环境的性质,并且有适合于各种用途的资源。     

Strategic Trend of Chinese Urban Forestry Development

1 STRATEGY BACKGROUND1.1 Quickening of Urbanization ProcessSince the reform and opening-up in China in 1978,economic community developed rapidly. By the endof 2003, GDP has exceeded $1 000 billion. With therapid development of Chinese economy, residentialmode focusing on rural population is now changing,urbanization process is quickening, traditional cityscale is expanding into metropolis (Tianjin, Xi’an,Chengdu, Chongqing, etc.) or super cities (Beijing,Shanghai, Guangzhou, etc.…     

The biochemical control of the cell cycle by growth regulators in higher plants

The cell cycle is an important research field in cell biology and it is genetically and developmentally regulated in animals and plants. The aim of this study was to review knowledge about the biochemical regulation of the cell cycle by plant growth regulators through molecular checkpoints that regulate the transition from G0-G1-S-phase and G2-M in higher plants.Recent research has shown that zeatin treatment led to the up-regulation of CycD3 in Arabidopsis. Benzyladenine treatment can also shorten the duration of S-phase through recruitment of latent origins of DNA replication. Kinetin is involved in the phosphoregulation of the G2-M checkpoint; the major cyclin-dependent kinase (Cdk) at this checkpoint has recently shown to be dephosphorylated as a result of cytokinin treatment, an effect that can also be mimicked by the fission yeast Cdc25 phosphatase. Gibberellic acid (GA) treatment induces internode elongation in deepwater rice, this response is mediated by a GA-induced up-regulation of a cyclin-Cdk at the G2-M checkpoint. Recent evidence has also linked abscisic acid to a cyclin-dependent kinase inhibitor. A new D-type cyclin, recently discovered in Arabidopsis may have a key role in this process. A brief review on plant growth regulator-cell cycle interfacing during development and a cytokinin-induced continuum of cell cycle activation through the up-regulation of a plant D-type cyclin at the G1 checkpoint and the phosphoregulation of the Cdk at the G2/M checkpoint had been concluded. This review could be valuable to research on cell and developmental biology in plants.     

Intratree Variability of Tensile Strength Parallel to Grain in Chinese Fir and I-214 Poplar from Plantation

The variation of tensile strength parallel to grain in Chinese fir and I-214 poplar wood from plantations was studied in this paper. Aaccording to the national standards The Testing Methods for Physical and Mechanical Properties of Wood (GB 1927 to 1943 ? 1991), the small clear wood samples were cut and tested, which represent the south and north of trees with heights of 1.3, 3.3, 5.3 and 7.3 m. The results showed: the tensile strength parallel to grain of the north wood was higher than that of south wood. ANOVA shows that the tensile strength parallel to the grain with height is of significant difference (at 0.05 level).     

A Study on the Effects of Insect Pests and Diseases on Intensively Managed Plantations

Basedon the results of monitoring the environment of China National Afforestation Project (NAP) and the investigation on insect pests and diseases in 1.2 million ha of plantations, the author elaborates the areas, species and causes of insect pests and diseases occurring in the project's areas and provides fundamental theory for guiding environmental protection and plantation establishment in a sound way. Since the project's activities strictly follovved the guideline of environmental protection in past five years, little losses were caused by some commonly insect pests and diseases.