Subjects: Geosciences >> Geography submitted time 2023-03-13 Cooperative journals: 《干旱区研究》
Abstract： Over the past 70 years, large-scale afforestation activities have been conducted in arid and semi-arid areas in China with remarkable success, but localized afforestation has failed due to regional human activities and climatic influences. Although the potential for afforestation in arid areas is recognized, it is unknown in which micro-region afforestation should be concentrated. Taking Shanxi Province, a typical region of the Loess Plateau, as an example, this study constructs a framework for the identification of forestable land and uses the PLUS and Markov models to simulate land use changes under different scenarios in 2030, analyzing woodland expansion, trends in internal changes in forest stands, and spatial distribution. The results show that: The current space for woodland growth in Shanxi Province is 5.38%, and the southeast is the main potential growth area; there is a possibility of woodland degradation at the edges of woodlands in the central and western parts of the province, while the degree of woodland fragmentation in the north is higher; the frequency of intra- forest conversion is higher; in order of expansion potential, there are woodland > shrubland > open woodland > other woodlands. In this context, a cautious attitude is taken toward large- scale afforestation in Shanxi Province. This study can provide a reference for effective afforestation management and enhancement of forest carbon sequestration levels in the Shanxi Province.
Subjects: Geosciences >> Space Physics submitted time 2017-03-10
Abstract：干涉仪利用通道间的相关运算进行测量，是干涉式成像的基本单元。太赫兹成像在安全检查、军事侦查等方面有着广泛的应用前景。将干涉成像测量引入太赫兹领域后，为解决相关运算中高速信号的相位同步问题，该文提出基于低速FPGA控制的交叉同步方案，用低硬件代价解决高速采样信号的相位同步问题，并完成了一套多通道高速数字相关系统。系统的最高采样速率为 5GHz，ADC有效位数大于等于6位，相关器积分时间可调。最后，利用该数字相关器和相应的太赫兹微波元器 件搭建了中心频率为 0.44THz的干涉仪，并得到了清晰的干涉条纹，其线性相位误差小于2°。该研究为今后设计太赫兹干涉成像仪提供了基本单元。
Peer Review Status:
Awaiting Review
Hits
Hits
Downloads
Comment