基于智慧课程的医学生实验报告网络提交系统应用研究

随着"互联网+教育"的开展及智慧校园、智慧课程的建设,互联网的应用也渗透到学校教育的方方面面。如何有效利用互联网组织教学、高效管理也是高校教师面临的问题。文章依托云平台将学生实验课的实验报告作业提交系统作为无纸化办公的研究对象,探讨了在医学生中开展作业网络提交系统的优劣,为智慧课程的立体建造提供思路。

泉州、晋江地区新生代红土地层划分的初步探讨

南方红土是我国秦岭-淮河以南广泛分布的新生代土状堆积,其重要性与北方风尘沉积可相提并论。自20世纪30年代开始,经历几代科学家不断地调查和研究,除一致认为它们是新生代红色风化壳以外,对其岩性特征、形成时代、地层划分、环境信息等各种问题都存在复杂的争论与不同意见,使其至今未能在我国新生代地质与环境研究中发挥其应有的重要作用。本研究通过在福建泉州、晋江地区新生代红土的调查和分析,根据其岩性特征及推测年代,将该区的红土划分为新近纪砖红壤红土、早更新世铁锰膜红土、中更新世中期网纹红土、中更新世晚期厚层红化土、晚更新世薄层红化土等5种类型,它们蕴涵了形成时的气候带及相应环境信息,为后续研究确定东亚气候环境的空间变化过程提供了依据。

黄土高原勺状沟壑特征及发育过程

沟谷是黄土高原物质交换最频繁,形态变化最剧烈的区域。在内外营力的共同作用下,不同发育阶段的各类沟谷塑造了黄土高原"千沟万壑"的独特地貌景观。在黄土高原沟壑系统中,广泛分布着一类特殊的黄土勺状沟壑,目前对其成因、发育过程与机理以及空间分布特征等的认知明显不足。本文以高分辨率遥感影像和DEM数据作为数据源,在大量野外调查和专家知识的基础上,首先提出了黄土勺状沟壑的概念,指出黄土勺状沟壑是独立发育于黄土坡面上的永久性沟谷。其次,从沟壑形态、汇流关系、侵蚀过程、分布特征等方面分析了黄土勺状沟壑区别于其他已有沟壑的特点。进而,从发育形态、发育规模、发育部位等角度对黄土勺状沟壑进行了分类,深化了对勺状沟壑的认识。再次,基于空代时理论,定量分析了黄土勺状沟壑发育过程的形态演变特征,进一步探讨了黄土勺状沟壑发育过程,论证了黄土勺状沟壑是黄土切沟的初期阶段。最后,在系统梳理总结勺状沟壑的特征及分类的基础上,提出了黄土勺状沟壑的发育过程设想,指出勺状沟壑的形成离不开黄土陷穴和暗穴的生成和发育,勺状沟壑的进一步发育伴随着水力侵蚀和重力侵蚀过程。勺沟尾部变细甚至消失,不能发育成更大规模的切沟,与地下暗穴、黄土渗透率、降雨条件以及地表覆盖有关。本文成果期望为进一步完善黄土沟谷地貌发育和侵蚀过程与机理等认识做出贡献,同时对黄土高原水土保持工作提供参考。

Geomorphological inheritance for loess landform evolution in a severe soil erosion region of Loess Plateau of China based on digital elevation models

The influence of pre-quaternary underlying terrain on the formation of loess landforms, i.e., the geomorphological inheritance issue, is a focus in studies of loess landforms. On the basis of multi-source information, we used GIS spatial analysis methods to construct a simulated digital elevation model of a pre-quaternary paleotopographic surface in a severe soil erosion area of the Loess Plateau. To reveal the spatial relationship between underlying paleotopography and modern terrain, an XY scatter diagram, hypsometric curve, gradient and concavity of terrain profiles are used in the experiments. The experiments show that the altitude, gradient and concavity results have significant linear positive correlation between both terrains, which shows a relatively strong landform inheritance relationship, particularly in the intact and complete loess deposit areas. Despite the current surface appearing somewhat changed from the original shape of the underlying terrain under different erosion forces, we reveal that the modern terrain generally smoothes the topographic relief of underlying terrain in the loess deposition process. Our results deepen understanding of the characteristics of geomorphological inheritance in the formation and evolution of loess landforms.

Early Pleistocene hominid teeth recovered in Mohui cave in Bubing Basin, Guangxi, South China

Two hominid teeth recovered in Mohui cave are morphologically distinguished from Australopithecus in Af-rica, but close to Homo erectus in China. These teeth are therefore provisionally assigned to Homo erectus. The associ-ated mammalian fauna include Gigantopithecus blacki, Nes-toritherium sp., Sus xiaozhu, Sus peii and Ailuropoda microta, which are typical early Pleistocene taxa in South China. The general characteristics of the Mohui faunal assemblage are similar to the Longgupo site, which is dated to 2 Ma, imply-ing a contemporaneity for the two sites. To date, compared with the discoveries in Africa, far fewer early Pleistocene hominid fossils have been recovered in Asia, and there are intensive controversies concerning their stratigraphic prove-nience and typological and temporal positions. The hominid fossils from Mohui cave, with their reliable biostratigraphic positions and distinct typological features, provide important evidence regarding the issue of early human origins and evo-lution.

Analysis of sedimentary-geomorphologic variation and the living environment of hominids at the Shuidonggou Paleolithic site

Shuidonggou is one of the most important Upper Paleolithic sites in North China. Due to the presence of rich human remains,animal fossils,abundant sporopollen and unique geological sequence,it is the type site for Late Pleistocene to Holocene human occupation and environmental change in the Ningxia-Inner Mongolia region. Many scholars suggest that the site should be named the "Shuidong-gou Formation" of Late Pleistocene in North China. Dating results indicate that ancient human activities at the site took place 30―24 ka (Marine Isotope Stage MIS 3). The climate at that time was warmer and moister than present day,and adequate precipitation led to the formation of water pack depressions where broad-leaf trees and sparse forest vegetations,as well as herbivorous animals flourished,mak-ing the area suitable for early human hunting,gathering and survival. The Neolithic human occupation happened 9―5 ka at the site,while similar environmental conditions with MIS3 occurred. The absence of human activity record in the region during the Last Glacial Maximum (MIS2) suggests that the envi-ronment was too harsh for humans to live there.

New evidence for human occupation of the northern Tibetan Plateau,China during the Late Pleistocene

The described stone artifacts are recovered from the 70 m-high terrace (4600 m a.s.l.) at the southeastern shore of the Siling Co on the northern Tibetan Plateau. The terrace was formed during the Interstadial period before the LGM, ca. 40-30 ka B.P. based on paleoenvironmental research. The Paleoliths from the Siling Co provide evidence for early human occupation of the northern Tibetan Plateau. They show technological and typological affinities with the European Middle Paleolithic suggesting that the early human occupation here might relate to migratory waves during the Late Pleistocene that dispersed humans across the Old World.

Paleotopographic controls on modern gully evolution in the loess landforms of China

The inhomogeneous and non-flat paleotopography in a depositional landform area profoundly controls the process of modern gully evolution and shapes the structure of a gully network.However,this controlling effect of paleotopography on modern gully evolution is mostly ignored because of the difficulties in paleotopography reconstruction.In this study,loess area in China is selected as case area for its typical depositional landform area and inhomogeneous and non-flat paleotopography during the Quaternary.The paleotopography underlying loess is considered while evaluating its controlling effects on the gully evolutionary process.On the basis of the geophysical prospecting,detailed geological information,and high-resolution digital elevation model,we reconstruct the pre-Quaternary paleotopographic surface in the case area.Comparative analysis is conducted to reveal the modern gully evolution in relation to the paleotopography.Results show that the concave area of the paleotopography acts as the basement of the high-order modern gully evolution in the hilly-gully area,although this concave area can be covered and buried by the loess depositional process during the Quaternary.A significant controlling effect of paleotopography on high-order modern gully evolution can be observed in a depositional landform with a hilly-gully underlying topography,whereas a relatively weak controlling effect exists in a flat underlying topographical area because of the strong horizontal shift effect of gully formation process.Several low-order modern gullies also exist and limit the controlling effect of paleotopography.These results reveal a controlled high-order modern gully evolutionary process and a rather dynamic low-order modern gully evolutionary process in the hilly-gully area.These results also help us understand the variations in different modern gully evolution in relation to paleotopography and the different management schemes for soil conservation and ecological restoration during the gully evolutionary process.

Luminescence chronology of “Old Red Sand” in Jinjiang and its implications for optical dating of sediments in South China

A weathered deposit in South China is widespread on the coastal areas of Fujian and Guangdong provinces,China.This deposit consists of slightly cemented,medium-to fine-grained sands,and is characterized by its colors of red,brown red,light reddish brown or dark yellowish orange,and is usually called "Old Red Sand".The uncertainty in its formation age has been a major obstacle to the study of this type of deposit.In this paper,optically stimulated luminescence(OSL) techniques were used to date the "Old Red Sand" sediments from Jinjiang,Fujian Province,China.The effect of the geochemical behavior of uranium and thorium in sediment during chemical weathering on estimation of annual dose was investigated.The results show that the change in annual dose due to weathering poses a major problem for the optical dating of such weathered sediments.The optical dating of these weathered deposits will produce erroneous ages if average annual dose during burial cannot be correctly estimated.For the profiles studied,the OSL dates obtained on samples from the upper part do not represent the burial age of the samples.It is highly likely that they are underestimated due mainly to the accumulated radioactive elements as a result of chemical weathering.It is concluded that changes in annual dose due to chemical weathering must be considered when dating similar sediments in South China.With a detailed analysis of the OSL dating results,the chronology of the marine terraces in this area was suggested.The lowest terrace was formed at ～3.5 ka and the second terrace was dated to ～74 ka.The age of the highest terrace may not be established accurately,but is inferred to be older than the apparent OSL date of～77 ka and so is the Paleolithic artifacts from it.