Analysis on Dynamic Characteristics of Landscape Patterns in Hailer and around Areas
This paper analyzed the spatial-temporal dynamic changes of landscape patterns in Hailer and around areas. Firstly, landscape patterns types of research area were divided into water, sand, farmland, city and grassland based on remote sensing images of 1986, 1991, 1996 and 2001 and field investigation. Then the grassland was classified into higher coverage grassland, high coverage grassland, medium coverage grassland and low coverage grassland by Normalized Difference Vegetation Index. Finally, the spatial-temporal dynamic changes of above-mentioned eight kinds of landscape patterns were analyzed using landscape ecology principle. The results indicated that human activities intensified significant from 1986 to 2001in research area. The area of grassland landscape decreased quickly, and the fragmentation extent intensified. The dominant landscape in research area changed from higher-high coverage grassland to medium-low coverage grassland. The expansion of sand landscape is obvious in periphery of road, city and farmland. The grassland vegetation degenerated seriously. Fragmentation of city landscape lightened, and city landscape patches tended to decrease and centralized. Economy development pattern of research area is in a stage that is transforming from extensive pattern to intensive urbanization pattern.
The Hulunbei'er prairie sand present situation draws back and the preventing and controlling countermeasure
Development trend analysis using weather station data(1961-2005) and six monthly temperatures,precipitation(1801-2004),as well as the 200-year drought,desertification was used to assess the effects of climate change and human activities on desertification of two areas of the Hulunbei'er grasslands.It showed that the growth and development of arid and dry climate warming was the result of human disturbance.Hulunbei'er grassland desertification area increased by 35.2% from 1994 to 1999 and by 32.3% from 1999 to 2004,an annual rate degradation rate of 1.35%.Artificial rain to give a major increase in rainfall in sandy areas is a major counter measure which would allow the development of eco-agriculture with both development and protection of grasslands from desertification.
Measurement and Demonstration of Thermal Expansion Coefficient
There are many classroom demonstrations, such as the ball-and-ring experiment, for showing the existence of thermal expansion of solids. The coefficient of linear expansion α (= increase in length divided by the original length times the change in temperature) may be measured in high school laboratories using a number of methods.1–4 In this paper we describe an especially simple experiment for determining α for a metal rod. It is based on the well-known optical lever method and is suitable for either a laboratory experiment or a classroom exercise.