卫星通信地球站终端技术的发展

本文介绍了卫星通信地球站终端技术的发展过程,初步论述了新技术应用的环境,为今后研制卫星通信设备提供某些参考。     

推进西部大开发亟待全面深化对内开放

要实现西部大开发的伟大战略构想,改变西部经济落后面貌,缩小东西部差距最终实现西部地区的经济现代化,市场化和国际化,亟待全面深化对内开放,打破地区封锁,建立统一开放竞争有序的国内大市场,优化资源配置,调整产业结构,发挥区域优势,东西部进行合理分工,增强企业竞争力,使西部的发展融入全国全球的经济体系中.     

中国沿海与内陆间经济影响的反馈与溢出效应

本文通过投入产出分析技术,总结了区域内乘数效应、区域间溢出效应与区域间反馈效应的经济含义,进一步探讨了它们的相互关系、乘法分解与加法分解的一致性问题,以及统一以最终需求为出发点的测度方法问题。在此基础上,利用2000年第一份中国8区域投入产出表,对中国沿海与内陆地区间的溢出与反馈效应进行实证分析。实证分析表明,沿海地区经济发展,对内陆地区的溢出效应并不明显,甚至于还不及内陆地区对沿海地区的溢出效应。正是由于这一影响,中国内陆地区的反馈效应不及沿海地区大。     

Quantifying and understanding land cover changes by large and small oil palm expansion regimes in the Peruvian Amazon

With rapid increases in global food demand and production, oil palm expansion constitutes a major emerging challenge for forest conservation in Amazonia and other tropical forest regions. This threat is evident in the Peruvian Amazon, where local and national incentives for oil palm cultivation along with growing large-scale investments translate into accelerated oil palm expansion. Environmental sustainability of oil palm cultivation in the Peruvian Amazon is contingent on policy incentives for expansion onto already-cleared lands instead of biodiverse, high carbon primary rainforests. Previous research indicates that while industrial plantations use less land area than local smallholders, companies have a higher tendency to expand into primary rainforests. However, the motivations behind these differing expansion scenarios remain unclear. In this study we combine data from optical and radar satellite sensors with training information, field discussions, and review of public documents to examine the policy incentives and spatial patterns associated with oil palm expansion by smallholders and industries in one of Peru’s most rapidly changing Amazonian landscapes: the Ucayali region of the city of Pucallpa. Based on our satellite-based land cover change analysis, we found that between 2010 and 2016, smallholders utilized 21,070 ha more land area for oil palm than industries but industrial expansion occurred predominantly in old growth forests (70%) in contrast to degraded lands for smallholders (56%). Our analysis of national policies related to oil palm expansion reveal policy loopholes associated with Peru’s “best land use” classification system that allow for standing forests to undergo large-scale agricultural development with little government oversight. We conclude that both sectors will need careful, real-time monitoring and government engagement to reduce old-growth forest loss and develop successful strategies for mitigating future environmental impacts of oil palm expansion.     

Real Existing Regionalism: The Region between Talk,Territory and Technology

In this essay, we propose the notion of real existing ‘lived’ regionalism as a rejoinder to the normative and ideological debates around new regionalism. Regional forms have shown little convergence in this age of globalized regionalization. Instead of an ideational construct or set of predictable practices, we argue that regionalism is a contested product of discourses (talk), territorial relationships (territory) and technologies (material and of power). The concept of real existing regionalism confronts the tensions between the discursive constructions and normative interventions characterizing much current regionalist debate and the territorial politics and technologies reflecting, generating and directing new state spatial strategic choices. The essay demonstrates the utility of the real existing regionalism framework through an analysis of the greenbelt, transport planning and post‐ suburbanization in Southern Ontario. We argue that regulatory institutions capture the Toronto region in a mix of rhetorical and technological change that complies with neither preconceived notions of regionalization nor the pessimism of total regional dysfunctionality. Rather, the lived experience of regionalization illuminates the emergent assemblages, multiplicity of everyday flows and ongoing multiscalar negotiations of diverse communities that produce the real existing region.     

STARFIX定位系统简介

本文简述了美国新近研制的一种卫星定位系统STARFIX的工作原理、系统组成、优缺点以及使用场合,并与美国现有的和将来使用的其他几种定位系统作了比较。文章给出了系统原理图、分系统方框图和性能比较表。     

Regional and Sector-specific Determinants of Industry Dynamics and the Displacement–replacement Effects

In this paper, we empirically assess the importance of regional and sector-specific determinants of industry dynamics. To this aim we test three hypotheses (originally proposed by Shapiro and Khemani (1987, Int J Indust Organ 5:15–26)) for the relationship between the entry and exit of firms: independence, symmetry and simultaneity. Estimates from a panel data system of equations seem to confirm the simultaneity hypothesis for Spain, i.e. we find evidence of a displacement (replacement) effect between the gross rate of entry (exit) and the gross rate of exit (entry). Also, our results show that, irrespective of the hypothesis we use, both sectorial and regional variables affect entry and exit.

欠发达地区农村金融支农的制约因素与对策分析——以甘肃省为例

社会主义新农村建设离不开农村金融的支持,甘肃省农村金融支持三农的力度虽然在逐年提升,但农村资金大量外流、支农贷款有效供给不足等问题仍很严重,其关键原因在于欠发达地区金融支持三农存在信贷体系的关键性机制缺失和农村发展落后等制约因素。本文针对欠发达地区农村金融支农的制约因素,提出了提高农村金融支农效能的对策。     

大频偏卫星扩频信号的基带处理算法的FPGA实现

多普勒频偏一直是卫星通信中不可忽视的消极因素。针对多路混叠的卫星扩频信号下变频以后所产生的大多普勒频偏,在匹配滤波结构中采取改进的部分相关算法,在基于并行导频的信道估计中根据信道状况改变估计长度,实现了大频偏下卫星扩频信号的基带处理。     

干旱区农地流转影响因素的实证分析——基于新疆农户样本数据

我国干旱区的农村土地流转在全国来说相对较为缓慢。为研究其原因,本文以新疆北疆地区、东疆地区和南疆地区的389户农民的有效问卷数据为依据,通过建立Logit回归模型,对农地流转的影响因素进行了系统分析。结果表明,影响新疆农户农地转入意愿的主要因素是农业生产条件、家庭人口、农业收入、农业优惠政策等;影响转出意愿的主要因素是家庭人口、非农收入、农村劳动力转移、农村社会保障制度等。因此,要推进干旱区农地流转。必须从政策方面予以支持。