Research on EPS application to very wide highway embankments in permafrost regions

In order to maintain the thermal stability of very wide highway embankments in permafrost regions, the thermal isolation material EPS is often utilized. To examine the effects of this insulation on the China National Highway (G214), two-dimensional finite element analysis of temperature fields was conducted for varying widths of highway embankments with and without EPS insulation. The numerical results show that in permafrost regions the effect of thermal aggregation on asphalt pavement is more obvious when highway embankments are wider, and, specifically for the G214 highway, the insulation should be more than 25 cm thick for 24-m-wide embankments. However, considering other factors such as the structural rationality of the embankments and high engineering costs, it might not be feasible to install EPS insulation in 24-m-wide embankments of the G214 highway when the height of the embankments is less than 3.65 m.     

鄂尔多斯地区退耕还林造林模式研究

通过对鄂尔多斯地区退耕还林造林模式的研究,在造林技术方面总结出先进适用又符合当地实际的造林模式。其中,①风沙区造林模式:旱柳、柠条防风固沙林,杨树、沙柳、柠条防风固沙林,柠条、紫穗槐防风固沙林;②丘陵沟壑区造林模式:油松+沙棘,沙棘+柠条,油松+山杏;③干旱硬梁区造林模式:柠条两行一带式植苗造林、旱柳、沙柳防风固沙林、榆树、柠条防风固沙林,取得了显著成效。造林实践表明,3a后保存率达100%,造林成活率大于70%的造林面积准格尔旗占84%、鄂托克旗占82%,生长状况优良。说明采用的造林模式是成功的,可以直接指导退耕还林等项目的建设和可供毗邻地区生产造林借鉴。     

Recent glacial retreat in High Asia in China and its impact on water resource in Northwest China

There are about 46298 glaciers in the High Asiain China, the total glacial area is about 59406 km , andtotal glacial volume about 5590 km3. These glaciersmainly concentrate around the Himalayas Mountains,Nyainqentanglha Mountains, Kunlun Mountains,Karakoram Mountains and Tianshan Mountains. Theglaciers in the Tibetan Plateau are the major compo-nent of the glaciers in the High Asia in China. Theseglaciers extend north to the arid and desert regions,and become the main water resource in …     

中国中部南洛河流域地貌、黄土堆积与更新世古人类生存环境

本文结合最近获得的新资料,对南洛河流域的地貌、黄土沉积和更新世环境进行综合分析。结果表明,南洛河上、中游地貌表现为河流峡谷和山间盆地相间分布的特征,盆地中河流阶地发育; 下游为平缓的山前平原和低山丘陵。黄土在全流域的山顶、河流阶地和盆地等各种地貌部位均有分布。黄土沉积受地形影响较大,上游黄土堆积速率低、颗粒细; 在下游有风道直通的地方,黄土堆积速率高、颗粒粗。在不同地貌部位,黄土开始堆积的年代不同,黄土底界的年代从早更新世到晚更新世均有所见。对埋藏旧石器的年代研究表明,南洛河流域的古人类活动从早更新世晚期(约800ka)开始,到晚更新世后期(约30ka)结束,期间有多期遗存。初步的孢粉和有机碳同位素分析表明,这里曾是森林草原景观,冰期时,乔木植被以松属为主,C4类型草本减少; 而间冰期时,乔木植被以松属-榆科占主导地位,C4类植物增多。古人类在黄土堆积期和古土壤发育期都可能在这个地方活动,但这一认识需要更多的证据支持。丰富的石制品分布和较为连续的黄土沉积,使南洛河流域成为理解更新世人类行为与环境的重要区域。     

New progress and problems of Quaternary moraine dating in the Tibetan Plateau

Since the 20th century, numerous Quaternary moraine dating methods have emerged, including lichenometric, moraine 14C, quartz sand thermoluminescence （TL）, electron spin resonance （ESR）, optically stimulated luminescence （OSL） and 10Be, 26A1, 36C1, 3H, 21Ne nuclide dating methods. These dating methods are widely applied to determine moraine ages and have provided a large dataset. Unfortunately each method has its defects. In this paper, we will review these various dating methods and provide some comments.     

建筑三维产权体空间关系剖析

城市土地的立体化开发利用促使土地管理模式由平面管理走向更精细的空间管理,当前的建造技术支持了各种形体的建筑建设,为三维产权空间管理提供了现实案例.三维地籍的核心是对产权体的描述与管理,本文从现实的多个三维建筑形体出发,从建筑物的三维产权体与地表形态的关系、与地表的方位关系以及与地表宗地的对应关系3个角度讨论建筑产权体的...     

基于灰色自记忆模型的城市月需水量预测

建立了以灰色微分方程为动力核的自记忆模型,并首次应用于城市月需水量预测.先将具有季节性特征的实测历史数据通过季节指数法获得相对平滑的序列,再用所建灰色自记忆模型进行模拟、预测.研究表明,灰色自记忆模型建模方法简单且模拟和预测精度较为满意,平均相对误差为5.74％,灰色GM(1,1)模型预测平均相对误差是8.77％,其精...     

地壳形变与密度变化耦合运动探析

为整体解释现代大地测量数据,提出了地壳变形与密度变化耦合运动的基本思想;分析了地壳变形与密度变化耦合运动的基本理论;导出了由地壳形变与密度变化耦合运动引起的重力时间变化一般严格公式。     

Movement process,geomorphological changes,and influencing factors of a reactivated loess landslide on the right bank of the middle of the Yellow River,China

Landslides - According to local villagers, the main Beiguo landslide on the Heyang Loess Tableland in China occurred several decades ago (the specific time is unknown). After the initial occurrence...     

Models of wave duration and event fre-quency of explosion aftershocks

IntroductionSeismologistsbeganaftershocksequenceinvestigationasearlyasendofthe19thcentury.Theaftershockoccurrencefrequencyhasdifferentmodels,whichincludepowerfunctiondecaymodel(Omori,1894),hyperboladecaymodel(Utsu,1961).Mogi(1962)presentedthattheafter-shockoccurrencefrequencydecayedwithdifferentprinciplesduringdifferenttimephasesaftermainshocks.Henceforthseismologistshavestudiedalargenumberofaftershocksequencesbasedonthesemodels.Chineseseismologistsstudiedthetemporal-spatialcharacteristicsof…