ATR72与“冲锋”8-Q400飞机分析对比与思考

对ATR72和"冲锋"8-Q400的设计特点、性能及销量等进行了分析对比,探讨了其中的原因。研究表明,该两型飞机都非常重视飞机的燃油经济性、环保性以及乘坐舒适性;但由于运营市场的定位不同,两型飞机在性能、销量等方面有着较大差别。     

论区域经济联动发展的系统构架

区域经济联动发展是经济全球化与区域经济一体化背景下的大势所趋,是立足全球发展、顺应世界经济潮流的必然选择.通过不同角度分析了区域经济联动发展的意义与内涵,概括了区域经济联动发展的主要特征,并就如何促进区域经济联动发展提出了策略和主张.     

构建廊坊市区域创新系统的对策研究

本文就廊坊如何建立区域创新系统进行了探讨，分析了廊坊构建区域创新系统在主体要素方面的问题，并结合国内外构建区域创新系统的实践探索，提出了构建廊坊市区域创新系统的思路与对策。     

浅析继续教育在区域经济发展中的作用

本文研究了继续教育对区域经济发展的重要意义。首先分析了继续教育在经济发展中的必要性,指出了继续教育在校企合作中遇到的问题,进而针对上述问题提出了完善校企合作的建议,并结合北华航天工业学院的继续教学院的人才培养实践,提出了有针对性的有效校企合作机制。     

基于全球网和区域网SLR数据的低轨卫星定轨精度分析

卫星激光测距(SLR)是目前低轨卫星常用的定轨手段之一.文章以贾森-1(Jason-1)和"环境卫星"(EN VISAT)实测数据为例,讨论了不同弧段长度(1天、3天和7天)的全球网SLR数据对低轨卫星定轨精度的影响,分析了基于美国网、欧洲网和亚洲网等区域网SLR数据的低轨卫星精密定轨精度.检验定轨精度的参考轨道来自美...     

2012–2014 China's Earth Observation and Earth Science Development

Human beings are now facing global and regional sustainable development challenges.In China, Earth observation data play a fundamental role in Earth system science research. The support given by Earth observation data is required by many studies, including those on Earth's limited natural resources, the rapid development of economic and social needs, global change, extreme events, food security, water resources, sustainable economic and urban development, and emergency response. Application operation systems in many ministries and departments in China have entered a stage of sustainable development, and the State Key Project of High-Resolution Earth Observation Systems has been progressing since 2006. Earth observation technology in China has entered a period of rapid development.     

Introduction to global short message communication service of BeiDou-3 navigation satellite system

Short Message Communication (SMC) is a featured service of BeiDou Navigation Satellite System (BDS). After its successful deployment in 2003, Regional Short Message Communication (RSMC) service has been continuously serving China and its neighboring countries and regions, especially in life safety scenarios. In this paper, the architecture of the Global Short Message Communication (GSMC) system is proposed based on the medium earth orbit (MEO) constellation and the crosslinks of the global BeiDou navigation system (BDS-3). Three subtypes of GSMC service, i.e. positioning report, emergency search and rescue (SAR) and regular SMC are designed in accordance with the technical characteristic of integration of navigation and communication in BDS-3, which supports future wide applications of GSMC. The performance of the designed GSMC system is analyzed by numerical calculations. As BDS-3 was officially announced completion on July 31, 2020, GSMC has been providing initial service. First test results of the in orbit GSMC payloads are also presented in the paper to verify the designed capabilities. Preliminary results also show that the requirements of Global Maritime Distress and Safety System (GMDSS) can also be fulfilled.     

Using vegetation indices and texture measures to estimate vegetation fractional coverage (VFC) of planted and natural forests in Nanjing city,China

Vegetation fractional coverage (VFC) is an important vegetation parameter affecting exchanges of carbon, water, energy between the atmosphere and surface. In this study, the applicability of tonal and texture measures calculated using an IKONOS_2 image in retrieving VFC of forests was investigated in the urban area of Nanjing city, China. Four spectral vegetation indices (VI) and six texture measures (TEX) were related to VFCs acquired from in situ measurements. Models for estimating VFC based on VIs or/and TEXs were established and validated for planted low broad-leaf forest plots (PLB), planted mature forest plots (PMF), natural broad-leaf forest plots (NBF), and all forest plots (ALLv), respectively. The results show that high spatial resolution remote sensing data is applicable to estimate VFC in urban areas, and TEXs may act as effective supplements of vegetation indices (VIs) for the retrieval of VFC. VIs are suitable for VFC estimation of mature forests (such as NBF and PMF) with high vegetation density, and TEXs can yield a more accurate estimate for planted forests (such as PLB and PMF) with regular spatial distribution if they are calculated with proper parameters, such as window size. The combination of VIs and TEXs improve the estimation of VFC if forest types are not previously differentiated. The results can be used as a reference for determining effective spectral or texture parameters in VFC estimation under similar environmental conditions according to vegetation maturity and regularity.     

天津市发展物流业的若干分析与建议

首先，从宏观角度出发，分析了天津市在京津冀经济圈中所处的地位及其在“十五”期间经济发展状况。又应用了区位熵的概念，分析天津市各类制造业的比较优势，从而论证了天津市发展物流中心的宏观可行性。接着，立足于世界港口集装箱吞吐量的预测，结合天津港保税区和天津空港物流加工区“十五”期间的发展，分析了天津市建设现代航运中心和物流中心所面临的机遇以及应注意的宏观机制问题。     

我国区域旅游经济非均衡发展的原因与对策

在分析目前我国东部、中部和西部旅游发展差异的基础上,探讨了旅游发展差异的原因,指出区域综合竞争力的差异导致了区域经济发展的不均衡,而区域经济的发展又是区域旅游经济发展的基础,由此导致了区域旅游发展的不均衡.因此,要减少中西部地区与东部地区的差距,必须提升中西部地区的综合竞争力,这不仅需要国家与东部地区在政策、资金等方面给予一定的支持,最根本的是需要中西部地区自己能够抓住机遇,利用自身现实的和潜在的优势,实现区域旅游全面、均衡的发展.