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91.
RTK-GPS�����������Ķ�Ƶ�ʳɷַ��� 总被引:2,自引:1,他引:1
???????RTK-GPS(????????λ??)???????????????????????????????????????????????????????RTK-GPS???????????????????????????????????????????????????????????е?? 相似文献
92.
长山列岛国家地质公园,位于胶东、辽东半岛之间的山东省长岛县,横跨黄、渤两海,由32座岛屿组成,岛陆面积56km^2,海域面积8700km^2,海岸线146km,辖8处乡镇,40个行政村,5.2万人口。地质地貌丰富,自然景观奇特,是全国唯一的国家级海岛地质公园。长山列岛国家地质公园于2005年9月被国土资源部批准建设。 相似文献
93.
海域条件下的气象观测具有数据稀少、变化大且观测站点分布不均的特点,其插值精度受插值方法影响较大。首先对常规插值方法进行理论分析,进而选取了反距离加权法、克里金法和样条函数法三种插值方法进行了插值实验和精度分析。根据渤海湾某区域的气象历史数据,采用不同方法绘制了温度、压强和湿度的插值平面图,并基于交叉验证的方式对各插值方法进行了对比,给出了不同方法的插值估算可靠性评价。结果表明:温度、压强和湿度的插值精度均是基于反距离加权法的插值结果最优(MAE_(温度)=2.42,RMSE_(温度)=1.92,MAE_(压强)=2.05,RMSE_(压强)=1.30,MAE_(湿度)=11.394, RMSE_(压强)=6.43),同时基于反距离加权法的图形绘制可视化效果也要优于其他两种方法。研究结果可为海域气象参数估算提供理论和实践依据。 相似文献
94.
Hao-Yi Wan Shu-Lei Cao Huan-Yu Teng Yu Liu Jian-Chen Zhang Tong-Jie Zhang 《天文和天体物理学研究(英文版)》2018,(10)
In order to explore the properties of cosmic neutrinos, i.e. sum of the neutrino mass(∑m_ν) and the effective number of neutrino species(N_(eff)), which affects the Hubble expansion rate H(z)and the power of observational Hubble parameter data(OHD) in constraining cosmological parameters under the ΛCDM model, we utilize OHD to constrain the properties of cosmic neutrinos and apply an accurate H(z) function with mνand Neff. First, we simulate new OHD beyond the existing 43 OHD. According to the predictions of measurements of H_0(the current H(z) value), baryon acoustic oscillations(BAO) peaks, Sandage-Loeb(SL) test and cosmic microwave background(CMB), we assume observational accuracy up to 2% and redshift 0 z ≤5. With simulated H(z) data obtained from the fiducial model, we constrain the parameters including mνand Neff. When all parameters are set free, mν 0.196 eV(95%) and N_(eff)= 2.984 ± 0.826(68%) are obtained, and when fixing Neff as the standard baseline 3.046, we attain ∑m_ν 0.240 eV(95%). These constrained results are much tighter than the ones obtained by the current OHD, which makes the prospect of OHD in constraining cosmological parameters more promising as its accuracy and quantity grow. 相似文献
95.
Xiaojie Mou Xingtu Liu Zhigao Sun Chuan Tong Jiafang Huang Siang Wan Chun Wang Bolong Wen 《中国地理科学(英文版)》2018,28(3):400-410
The changes in soil organic carbon(C) mineralization as affected by anthropogenic disturbance directly determine the role of soils as C source or sink in the global C budget. The objectives of this study were to investigate the effects of anthropogenic disturbance(aquaculture pond, pollutant discharge and agricultural activity) on soil organic C mineralization under different water conditions in the Minjiang River estuary wetland, Southeast China. The results showed that the organic C mineralization in the wetland soils was significantly affected by human disturbance and water conditions(P 0.001), and the interaction between human disturbance activities and water conditions was also significant(P 0.01). The C mineralization rate and the cumulative mineralized carbon dioxide-carbon(CO_2-C)(at the 49th day) ranked from highest to lowest as follows: Phragmites australis wetland soil aquaculture pond sediment soil near the discharge outlet rice paddy soil. This indicated that human disturbance inhibited the mineralization of C in soils of the Minjiang River estuary wetland, and the inhibition increased with the intensity of human disturbance. The data for cumulative mineralized CO_2-C showed a good fit(R~2 0.91) to the first-order kinetic model C_t = C_0(1 – exp(–kt)). The kinetic parameters C_0, k and C_0 k were significantly affected by human disturbance and water conditions. In addition, the total amount of mineralized C(in 49 d) was positively related to C_0, C_0 k and electrical conductivity of soils. These findings indicated that anthropogenic disturbance suppressed the organic C mineralization potential in subtropical coastal wetland soils, and changes of water pattern as affected by human activities in the future would have a strong influence on C cycling in the subtropical estuarine wetlands. 相似文献
96.
As the feature size of the CMOS integrated circuit continues to shrink, the more and more serious scattering effect has a serious impact on interconnection performance, such as delay and bandwidth. Based on the impact of the scattering effect on latency and bandwidth, this paper first presents the quality-factor model which optimises latency and bandwidth effectively with the consideration of the scattering effect. Then we obtain the analytical model of line width and spacing with application of curve-fitting method. The proposed model has been verified and compared based on the nano-scale CMOS technology. This optimisation model algorithm is simple and can be applied to the interconnection system optimal design of nano-scale integrated circuits. 相似文献
97.
银川平原植被生长与地下水关系研究 总被引:15,自引:1,他引:14
干旱区植被生长与地下水的关系是生态水文地质学研究的热点之一。西北内陆干旱地区降水稀少,植被的生长发育与地下水的关系极为密切,从大尺度上研究地下水变化的生态效应问题对生态环境的保护和恢复具有重要的意义。借助遥感方法,结合地下水观测数据,在区域尺度上定量地研究了中国银川平原地区地下水埋深及矿化度与植被生长的关系。结果表明:适宜植被生长的地下水埋深范围约为1~6m,当地下水位埋深为3.5m左右时,植被长势最好。而在水位埋深为3.5m左右的地区,植被生长的相对好坏又受地下水矿化度的影响。当地下水矿化度为0.9g/L时对该地区植被的生长最为有利。 相似文献
98.
99.
During the process of one‐dimensional consolidation with a threshold gradient, the seepage front moves downward gradually, and the problem is indicated as a Stefan problem. The novel feature in this Stefan problem is a latent heat that varies inversely with the rate of the moving boundary. An exact solution for the external load that increases in proportion to the square root of time is constructed using the similarity transformation technique. Computational examples concerning the effect of different parameters on the motion of the seepage front are presented. The exact solution provides a worthwhile benchmark for verifying the accuracy of numerical and approximate methods. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
100.
本文从实践和理论两方面讨论了应用构造地球化学图解分辨玄武质岩石产出的大地构造环境这一方法所存在的问题,认为J. A. Pearce等给出的构造地球化学图解,在很大程度上,是一种岩性分辨图解,图解分辨中存在不确定性的根本原因是控制玄武质岩石形成的条件参数与构造环境并不完全存在一一对应的映射关系,应用图解应持谨慎态度。 相似文献