沙丘

The density on the leeward slope is the smallest, closing to the minimum dry density of this sample.

线性沙丘上，则是沙丘脊部沙土的密度最大，接近该类沙丘沙样最大干密度，两腰部密度较小。

0M/s.(4) The barchans dunes developed in narrow un-modal wind regime, the value of RDP/DP is greater than 0.8; the compound longitudinal dunes mainly developed in modal wind regime whose value of RDP/DP is about 0.55; the dome dunes developed in those areas that have directional winds and their force is balanced; and the star dunes mainly distributed in areas which have wavy terrain or approach mountains.

4塔克拉玛干沙漠新月形沙丘及沙丘链主要是在窄单峰风环境中发育而成，RDP/DP值一般都在0.8以上；复合型纵向沙垄主要是在双峰风况条件下发育而成的，RDP/DP值在0.55左右：穹状沙丘形成于均衡的多风向地区；而金字塔沙丘一般都形成于下伏地面微有起伏或邻近山岭的地带。

The barchans dunes developed in narrow un-modal wind regime, the value of RDP/DP is greater than 0.8; the compound longitudinal dunes mainly developed in modal wind regime whose value of RDP/DP is about 0.55; the dome dunes developed in those areas that have directional winds and their force is balanced; and the star dunes mainly distributed in areas which have wavy terrain or approach mountains.

塔克拉玛干沙漠新月形沙丘及沙丘链主要是在窄单峰风环境中发育而成，RDP/DP值一般都在0.8以上；复合型纵向沙垄主要是在双峰风况条件下发育而成的，RDP/DP值在0.55左右；穹状沙丘形成于均衡的多风向地区；而金字塔沙丘一般都形成于下伏地面微有起伏或邻近山岭的地带。

Reddish and orange-coloured dunes, dunes behind dunes beyond dunes

泛红的和橙色的沙丘，沙丘续着沙丘，沙丘远处还是沙丘。

The results shows that the number of rhizosphere soil microbes in fixeddune and semifixed dune are aerophile bacteria）actinomyces） fungi.

研究了鄂尔多斯4种典型固沙植物柠条、沙柳、杨柴、油蒿在固定沙丘和半固定沙丘两种立地条件下根际土壤微生物数量、组成的季相变化，结果表明固定沙丘和半固定沙丘根际微生物数量为好气性细菌〉放线菌〉真菌。

The results showed that the flow reattachment distance in the lee side of various dune models are ranged from 4.8H to 10.8H depending on different stoss slopes, the maximum of flow reattachment distance was found in the lee side of the transverse dune with a 15° stoss slope angle.

实验结果表明，当来流风速垂直于沙丘脊线时，沙丘背风侧的气流重附距离介于4.8H～10.8H之间，最大重附距离出现在迎风坡坡度为15 的沙丘背风侧；沙丘迎风坡坡度是控制背风侧气流重附距离的主要因素，而自由风速对气流重附距离的控制作用较小。

The field experiments on the secondary flow developed on the lee side show that there are strong sand transport potential at the lee side of the dunes near the surface because of the decreasing of the sand grain size and the other factors. The transport directions are nearly vertical to the dune trends. Those factors and the sand slumping on slip face, and the sand transport processes on the stoss slope make the transverse dunes maintaining their morphology under the advance processes.

对沙丘背风坡发育的二次流的野外观测表明，近地面一定高度内沙丘背风坡气流仍有一定的强度，由于背风坡的沙丘沙粒径较小等因素，背风坡气流仍保持一定强度的输沙率，输沙方向与沙丘走向基本上垂直，这种作用与沙物质向背风坡崩落、迎风坡的输沙过程等共同作用，因而使横向沙丘在运动中保持其形态。

Velocity speeding\|up on the windward flanks of barchans is a dynamic factor which control dune formation and dune shape.

迎风坡气流加速是决定新月形沙丘发育和形态的动力因子，研究这一加速过程的定量关系有利于认识沙丘的发育、沙丘的形态、沙丘的运动等。

Huangsha in large梅沙沙丘sites found in pottery, stone tools show that as early as the Neolithic Age五六千年before, there are human beings live in this beautiful and fertile land.

在大黄沙、大梅沙沙丘遗址发现的陶器、石器显示，早在五六千年前的新石器时代，就有人类生息在这片美丽富饶的土地上。

We have observed the structure of these dune sands and analyzed the grain-size,surface textural features and several main chemical elements of them,the results showed that:(1) these dune sands have some eolian structure characteristics which are similar to the recent dune sands;(2) they are also similar to the recent dune sands in grain-size components,and parameters of Mz,?滓,Sk and Kg,as well as in several main chemical components;(3) the scatter plots of Mz-?滓,SiO2-Al2O3+TOFE and the probability curves of grain-size showed that these paleo dune sands are different from paleosols and fluvio-lacustrine facies but are consistency with recent dune sands;and(4) the quartz sands have well roundness and some surface textural features such as dish-shape pits,crescent-shape pits,pockmarked pits,upturned cleavage plates,siliceous precipitates and siliceous crevasses,indicating that they had been carried for a long time by the wind.

对这些沙丘砂的沉积构造观察以及粒度、扫描电镜和常量化学元素分析结果表明：(1)这些沙丘砂具有与现代沙丘砂相似的风成沉积构造特征；(2)粒度及其参数--Mz、σ、Sk和Kg，以及主要化学组分SiO2、Al2O3和TOFE也与现代沙丘砂相近；(3)Mz-σ、SiO2-Al2O3+TOFE散点图和概率累积曲线显示这些沙丘砂与萨拉乌苏组中的河湖相、古土壤差别明显，而与现代沙丘砂一致；(4)石英砂颗粒具有良好的磨圆以及碟形坑、新月形坑、麻坑、上翻解理薄片、硅质沉淀和硅质裂纹等表面结构特征，反映其曾受持久的风力搬运作用。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。