一种改进的差分空时协同分集方案及误码性能分析

提出了一种分布式差分空时分集方案,通过对差分编码方式的改进,可使用多种星座形状来进行调制。在采用了QAM星座调制时,比传统的PSK调制具有更好的性能,可以改善无线网络中的能量效率。在不考虑协同节点间误码的情况下,分析和推导了平坦衰落瑞利信道下该方案的SER性能上限的表达式。仿真结果表明采用QAM调制下的DSTBC性能优于PSK调制下的DSTBC。同时在慢衰落的条件下,仿真结果和理论分析的结果吻合较好,说明了方案的有效性。

雷达网航迹欺骗干扰协同规划技术

空时协同是实施雷达网虚假航迹欺骗干扰的关键技术,也是面临的实际困难之一。针对这一问题,提出了一种基于集中航迹规划和分布航迹协同的雷达网航迹欺骗干扰技术。首先,在基准雷达极坐标系内设计基准航迹,然后将基准航迹转化到地心直角坐标系(Earth-Centred,Earth-Fixed,ECEF)内,得到统一坐标系下的基准航迹。由于干扰设备须在雷达极坐标系内进行参数标定,因此将基准航迹转化到各雷达极坐标系内,完成空间上的航迹规划。而后通过干扰设备上的GPS模块对启动时间进行统一,并对基准航迹进行插值,计算出虚假航迹与雷达扫描的交汇点,完成时间上的统一,最后由干扰设备释放干扰,由此融合中心得到空时高度相关的上报航迹,容易将其误判为一条虚假航迹。试验结果验证了该方法的可行性、实用性。

Regional Evolution Features and Coordinated Development Strategies for Northeast China

Northeast China, as the most important production base of agriculture, forestry, and livestock-breeding as well as the old industrial base in the whole country, has been playin a key role in the construction and development of China＇s economy. However, after the policy of reform and open-up was taken in China. the economic development speed and efficiency ofthis area have turned to be evidently lower than those of coastal area and the national average level as well, which is so-called ＇Northeast Phenomenon＇ and ＇Neo-Northeast Phenomenon＇. In terms of those phenomena, this paper firstly reviews the spatial and temporal features of the regional evolution of this area so as to unveil the profound forming causes of ＇Northeast Phenomena＇ and ＇Neo-Northeast Phenomena＇. And then the paper makes a further exploration into the status quo of this region and its forming causes by analyzing its economy gross, industrial structure, product structure, regional eco-categories, etc. At the end of the paper, the authors put forward the basic coordinated development strategies for Northeast China. namely we can revitalize this area by means of adjustment of economic structure, regional coordination, planning urban and rural areas as a whole, institutional innovation, etc.

Spatiotemporal interpolation of precipitation across Xinjiang, China using space-time CoKriging

In various environmental studies, geoscience variables not only have the characteristics of time and space, but also are influenced by other variables. Multivariate spatiotemporal variables can improve the accuracy of spatiotemporal estimation. Taking the monthly mean ground observation data of the period 1960–2013 precipitation in the Xinjiang Uygur Autonomous Region, China, the spatiotemporal distribution from January to December in 2013 was respectively estimated by space-time Kriging and space-time CoKriging. Modeling spatiotemporal direct variograms and a cross variogram was a key step in space-time CoKriging. Taking the monthly mean air relative humidity of the same site at the same time as the covariates, the spatiotemporal direct variograms and the spatiotemporal cross variogram of the monthly mean precipitation for the period 1960–2013 were modeled. The experimental results show that the space-time CoKriging reduces the mean square error by 31.46% compared with the space-time ordinary Kriging. The correlation coefficient between the estimated values and the observed values of the space-time CoKriging is 5.07% higher than the one of the space-time ordinary Kriging. Therefore, a space-time CoKriging interpolation with air humidity as a covariate improves the interpolation accuracy.

The development of real time data driving multi-axis linkage and synergic movement control system of 3D variable cross-section roll forming machine

The three dimensional variable cross-section roll forming is a kind of new metal forming technol- ogy which combines large forming force, multi-axis linkage movement and space synergic movement, and the sequential synergic movement of the ganged roller group is used to complete the metal sheet forming according to the shape of the complicated and variable forming part data. The control system should meet the demands of quick response to the test requirements of the product part. A new kind of real time data driving multi-axis linkage and synergic movement control strategy of 3D roll forming is put forward in the paper. In the new control strategy, the forming data are automatically generated according to the shape of the parts, and the multi-axis linkage movement together with cooperative motion among the six stands of the 3D roll forming machine is driven by the real-time information, and the control nodes are also driven by the forming data. The new control strategy is applied to a 48 axis 3D roll forming machine developed by our research center, and the control servo period is less than 10ms. A forming experiment of variable cross section part is carried out, and the forming preci- sion is better than ＋ 0.5mm by the control strategy. The result of the experiment proves that the control strategy has significant potentiality for the development of 3D roll forming production line with large scale, multi-axis ganged and svner^ic movement

Smart Nanomedicine for Ondemand Drug Release and Synergistic Antitumor Therapy

Smart nanoparticles（NPs）that respond to external and internal stimulations have been developing to achieve optimal drug release in tumor.However,applying these smart NPs to attain high antitumor performance is hampered by limited drug carriers and inefficient spatiotemporal control.Recently,a research team led by CAI Lintao from the Institute of Biomedicine and Biotechnology,

Spatio-temporal Differentiation of Trade-offs and Synergies of Ecosystem Services in Typical Mountain Areas of China

Mountain area accounts for a high proportion of the land area in China,and it is the focal area to solve the contradiction of imbalanced regional development,as well as an important source of ecosystem services.Therefore,this area has been facing long-term pressure and challenges in economic development and ecological protection.In this paper,we selected a rocky desertification mountain area,an active mountain area of new tectonic movement and a typical northern earth-rock mountain area,as Qian-Gui karst Mountain area,Hengduan Mountain area and Taihang Mountain area,as examples to represent three main types of mountain areas.Three representative types of ecosystem services,including NPP(Net Primary Productivity)as a support service,water conservation as a regulation service,and agricultural produce as a supply service,were incorporated into this study.Linear regression,correlation analysis and other methods were then used to investigate the spatial-temporal characteristics of the trade-offs and synergies in each of the three kinds of mountain areas during 1990-2015 in China.The analysis yielded three main conclusions for the three mountainous areas.(1)The agricultural produce supply service decreased relatively,while the support and regulation services of NPP and hydrological regulation increased significantly.(2)There was a synergistic relationship between NPP and the hydrological regulation services in the three mountainous areas.The synergistic relation in Qian-Gui karst Mountain area became enhanced,while those in Hengduan and Taihang Mountain areas became weakened,and the former was weakened to a greater extent.There was a trade-off between NPP,the hydrological regulation service and the agricultural produce supply service among the three mountainous areas.In particular,the trade-off between NPP and the agricultural produce supply service in Qian-Gui karst Mountain area became weaker,while those in Hengduan and Taihang Mountain areas were enhanced,and the latter was enhanced to a greater degree.(3)Significant spatial differentiation was evident in the trade-offs and synergies of ecosystem services among the three mountain areas.