沙埋对河西走廊荒漠绿洲过渡带一年生草本植物的影响

一年生草本植物是荒漠绿洲过渡带入工固沙植物群落草本层的优势植物类群,由于风沙活动剧烈,风蚀和沙埋成为一年生草本植物生存的关键选择动力因素.以河西走廊荒漠绿洲过渡带典型一年生草本植物狗尾草(Setaria viridis)、虎尾草(Chloris virgata)、白茎盐生草(Halogeton arachnoideus...     

天然碱性长石的高分辨电镜观察

利用高分辨电子显微镜观察了产于河北汉诺坝玄武岩中碱性长石的精细结构。不同取向的高分辨像清楚地显示了钾、钠长石形成的片层状多重紧密连生体以及各种调制结构。钾、钠长石的连生界面一般为(601)晶面。其超微结构特征与在中等冷却速率下钾钠长石中按旋节分解机制产生的熔离结构相符。以(010)面为孪晶界面的多重连生微孪晶构成了平均周期约为8*d_(010)的调制结构。     

Responses of Yellow Sea Cold Water Mass to Typhoon Bolaven

A two-month seabed-mounted observation(YSG1 area) was carried out in the western Yellow Sea Cold Water Mass(YSCWM) using an RDI-300 K acoustic Doppler current profiler(ADCP) placed at a water depth of 38 m in late summer, 2012. On August 2012, Typhoon Bolaven passed east of YSG1 with a maximum wind speed of 20 m s-1. The water depth, bottom temperature, and profile current velocities(including u, v and w components) were measured, and the results showed that the typhoon could induce horizontal current with speed greater than 70 cm s-1 in the water column, which is especially rare at below 20 meters above bottom(mab). The deepening velocity shear layer had an intense shear velocity of around 10 cm s-1 m-1, which indicated the deepening of the upper mixed layer. In the upper water column(above 20 mab), westward de-tide current with velocity greater than 30 cm s-1 was generated with the typhoon's onshore surge, and the direction of current movement shifted to become southward. In the lower water column, a possible pattern of eastward compensation current and delayed typhoon-driven current was demonstrated. During the typhoon, bottom temperature variation was changed into diurnal pattern because of the combined influence of typhoon and tidal current. The passage of Bolaven greatly intensified local sediment resuspension in the bottom layer. In addition, low-density particles constituted the suspended particulate matter(SPM) around 10 mab, which may be transported from the central South Yellow Sea by the typhoon. Overall, the intensive external force of the Typhoon Bolaven did not completely destroy the local thermocline, and most re-suspended sediments during the typhoon were restricted within the YSCWM.     

Numerical study of shoreline changes by emergency beach nourishment project at the Middle Beach of Beidaihe, China

Beach nourishment is a common coastal management strategy used to protect beach from erosion along the sandy coastlines. This method has been successfully applied to an emergency project at the West Beach of Beidaihe in the summer of 2008 and the full West Beach nourishment project in 2009-2010, which is the direct base of this study. Some basic information about the emergency engineering area at the Middle Beach is firstly described. The shoreline change of this area, including the analysis of beach width in five monitoring profiles in the bathing places of Middle Beach, is then discussed. After that a numerical model based on one-line theory is established and the numerical results agree well with the measured shorelines, which indicates that the model is appropriate and is qualified to predict the shoreline change of the Middle Beach. With the same model and parameters, long-term performance of the project is predicted, and the result shows that without follow-up nourishment and project, the bathing places can remain suitable for bathing for about 10 a. It is suggested to nourish the beach in time and carry out the beach nourishment project for the full Middle Beach in Beidaihe.     

Seasonal distribution and relationship of water mass and suspended load in North Yellow Sea

The concentration of suspended load can be determined by its linear relationship to turbidity. Our results present the basic distribution of suspended load in North Yellow Sea. In summer, the suspended load concentration is high along the coast and low in the center of the sea. There are four regions of high concentration in the surface layer: Penglai and Chengshantou along the north of the Shandong Peninsula, and the coastal areas of Lüshun and Changshan Islands. There is a 2 mg/L contour at 124°E that separates the North Yellow Sea from regions of lower concentrations in the open sea to the west. And there is a 2 mg/L contour at 124°E that separates the North Yellow Sea from regions of lower concentrations in the open sea to the west. The distribution features in the 10 m and bottom layer are similar to the surface layer, however, the suspended load concentration declines in the 10 m layer while it increases in the bottom layer. And in the bottom layer there is a low suspended load concentration water mass at the region south of 38°N and east of 123°E extending to the southeast. In general, the lowest suspended load concentration in a vertical profile is at a depth of 10 to 20 m, the highest suspended load concentration is in the bottom near Chengshantou area. In winter, the distribution of suspended load is similar to summer, but the average concentrations are three times higher. There are two tongue-shaped high suspended load concentration belt, one occurring from surface to seafloor, extends to the north near Chengshantou and the other invades north to south along the east margin of Dalian Bay. They separate the low suspended load concentration water masses in the center of North Yellow Sea into east and west parts. Vertical distribution is quite uniform in the whole North Yellow Sea because of the cooling effect and strong northeast winds. The distribution of suspended load has a very close relationship to the current circulation and wind-induced waves in the North Yellow Sea. Because of this, we have been able to show for the first time that the distribution of suspended load can be used to identify water masses.     

双语地图中地图注记的设计

从汉语地名的译写现状出发,对目前采用的两类地名译写方法进行分析,总结了地名翻译过程中的专名音译,通名意译的一般原则和相关要点。随后探讨加入英文注记后信息量增加、英文字符和排列等因素带来的双语地图在注记字体、尺寸、字隔、配置四个方面设计上与传统地图的不同之处;并结合编制广州市2010年亚运场馆分布地图的的实践,探讨如何在双语地图中对地物信息进行科学、清晰、美观的语言表达。     

Performance and prediction of long-term settlement in road embankments constructed with recycled construction and demolition waste

The settlement of highway embankments can directly affect the structural safety of road pavement. Comprehensive assessment of the long-term settlement characteristics of highway embankments is important in highway safety management. The present study conducted long-term settlement monitoring in an embankment of the Xi’an-Xianyang Highway in Shaanxi Province, China, that was constructed with recycled construction and demolition waste. Variations in sectional settlement, cumulative settlement, differential settlement, and settlement rates were made in a barricade section and an arc-shaped protective slope section. The maximum settlement observed in the barricade section was 51.75 mm, with the embankment exhibiting “basin-shaped” settlement. The maximum settlement in the arc-shaped protective slope section was 42.22 mm, and the embankment exhibited “W-shaped” settlement. Furthermore, there were two stages of great increase in the settlement rate. Based on the results, control standards for the sectional settlement of embankments constructed with recycled construction and demolition waste are proposed. Finally, a model for predicting the long-term settlement in road embankments constructed with recycled construction and demolition waste is established based on a Weibull distribution probability density function.

     

基于改进Harris算法的高分辨率遥感影像建筑物角点检测研究

高分辨率影像具有空间分辨率高、光谱分辨率相对不足的特点,在多领域中具有广阔的应用前景。利用Google Earth高分辨率遥感影像作为数据源,对其红、绿、蓝通道图像,以及三通道取平均的全色通道图像进行建筑物角点检测,并根据建筑物在影像上具有几何角点的特点,对Harris算法的一阶梯度算子进行4种方向上的改进。对Google Earth的红、绿、蓝、全色4种图像进行试验,从4个检测方向上检测并累加,结果表明红色通道的图像检测效果较好。利用4种改进梯度算子进行累加的建筑物角点识别,识别正确率可到74.75%,识别效果较好。结果表明,该方法可以很好地实现高分辨率影像建筑物的角点检测,具有一定的理 论研究和实际应用价值,可为建筑物自动识别提供技术参考。     

GNSS接收机室内检定方法研究初探

当前,我国开展的GNSS接收机检定工作是借助室外检定场进行的,具有很大的局限性。开展GNSS接收机室内检定方法的研究,有利于客观地对各类卫星导航定位接收机产品的测量精度、定位精度和各项计量性能等做出定量、有效、精确的评估和校正,具有重要的现实意义。     

基于无人机影像的漾濞地震房屋震害定量评估

2021年5月21日,云南漾濞县发生MS6.4地震,震源深度8 km.文中将无人机遥感技术引入云南漾濞县6.4级地震房屋震害评估工作中,结合无人机影像数据和现场地面调查数据,建立房屋震害遥感解译标志,提取漾濞县城部分区域的房屋震害信息,进行遥感定量评估.通过与房屋震害现场调查统计结果的对比分析,房屋震害遥感定量评估结果...