大四专业课学生本位教学模式探索——以3S为例

针对大四专业课教育中出现的学生到课率低、学习兴趣不高、学习效果较差等问题,剖析"大四现象",围绕如何增强专业课的吸引力,从教育的本质出发,提出采用突出"学生本位"与"过程考核"的教学改革思路。以河南理工大学地理信息系统专业的"3S集成技术"课程为例,在分析该课程特点的基础上,通过改革考试模式,设置专题汇报、引入基于微信问卷的学生自主评价体系等方式予以实施。教学实践表明,该方式学生易于接受,使学生的学习积极性得以显著提高、综合能力得到锻炼。     

全球森林治理:理念、现状、问题与挑战

当前气候变化是国际社会普遍关注的全球性问题,各国携手发展林业应对气候变化,共同推进绿色、低碳发展已成为当今世界的主流.因此,实施森林治理、发展现代林业是全球环境治理及可持续发展的客观需求.但因全球森林治理体系和机制仍不健全,使得世界林业发展依然面临着严峻挑战,这就需要加强对全球森林治理问题的研究和实践.     

中国城市网络等级结构特征及组织模式——基于铁路和航空流的比较

交通流是反映城市间社会经济联系的重要表征,被广泛应用于城市网络研究中。基于2010年中国城际铁路与航空客流OD数据,本文从城市节点、流量、子网络视角对中国城市网络的结构特征与组织模式进行了比较研究,发现：① 铁路与航空流视角下的中国城市网络均呈现出以北上广为顶层节点的空间等级结构体系,但除顶层结构外两种网络结构差异较大。② 城市网络体系中的铁路流联系表现出空间邻近性特征,而航空流联系则主要受到城市节点的规模大小与职能属性的影响。③ 铁路流的首位联系受省级行政区划的制约,航空流的首位联系空间跨度大,形成了若干具有垂直层间联系的地域子系统。④ 铁路网络拥有具有显著地域特征的7个子网络,而航空网络中则不存在明显的子网络。技术经济特征与管理体制是造成铁路与航空两种网络特征差异的主要原因。     

Potential Impacts of Proposed Chenglingji Hydraulic Project on Wetlands in Dongting Lake

Water level fluctuation of is an important ecological character of lakes in monsoon climate zone.It is the key driver to seasonal change of the wetlands and associated habitats,which provide vital inhabiting conditions for different species in summer and winter,or,wet season and dry season.Due the hydrologic regime changes in the recent years after the operation of Three Gorges Dam,in 2012,the government of Hunan province proposed Chenglingji Hydraulic Project,aiming at water level control in dry season at Chenglingji,where the outlet of Dongting Lake located.Through different operations on water retreat process,five scenarios on the water level control from 21 m to 24 m were set in the plan.The potential ecological impacts of the project are under enormous public concern.To analyze potential impacts from different scenarios of water level control on the wetlands,this paper studied the topography of Dongting Lake bed and wetlands in dry season,by using Digital Elevation Model(DEM)and 15 images from HJ satellite and 1 image from Landsat TM.The wetlands at water levels of 19 m to 27 m were analyzed.The study revealed that there were 4 terrain steps on Dongting Lake bed from the West Dongting Lake to East Dongting Lake.Water level control at Chenglingji would increase area of open water in East Dongting Lake and Hengling Lake areas,while its effect on South Dongting Lake and West Dongting Lake areas due to higher terrain was weaker.Particularly,the area percentages of South Dongting Lake area did not change with water level fluctuation,due to its 2 elevation steps.The area percentages of various types of the wetlands in Dongting Lake area during the processes of water level rising and retreating were quite different,even in the relatively close water level interval.The retreating area of open water in autumn was larger than that during the spring flooding.The 23 m was the key water level,a turning point of the area change of the wetlands in Dongting Lake area.Areas of open water,mudflat,meadows and their percentages changed significantly at water levels above 23 meters,with increasing of open water area and shrinking of meadow area,their areas would decrease 30 000 ha.As the key habitats for wintering geese,the area of meadows was from near 70 000 ha to 10 000 ha.Among 5 scenarios,the impact of the scenario at 21 m elevation on wetlands was the weakest.However,water level dropping was still postponed than that of natural hydrological process in the scenarios.It resulted in longer inundation of large area of lakebed at elevation of 22-23 m,increasing habitats for aquatic biodiversity but reducing area of the meadows,where is the key habitat for wintering geese.All the other water level control scenarios would cause large area of inundation of lakebed in dry season and dramatic change of wetlands.To maintain the natural wetlands in Dongting Lake area,the Chenglingji Hydraulic Project should be considered in a more cautious way and further researches were needed on the response of aquatic biodiversity and wintering water birds.     

“ 中欧班列”陆路运输腹地范围测算与枢纽识别

自“一带一路”战略实施以来,中国各地政府大力推进中欧国际班列运输,试图改变传统的对外贸易运输体系,强化提升新欧亚大陆桥运输作用。然而,设施联通、运输价格、货源及复杂的地缘政治环境等问题仍然是制约中欧班列发展的重要因素。为此,本文在分析“中欧班列”运营现状及存在问题基础上,提出实现其高频率常态运营的“轴-辐”运输组织模式。通过构建高、中、低三种运价方案,利用距离—经济成本分析法划分“中欧班列”主要出境口岸的经济腹地范围;并综合考虑各城市的铁路技术指标、集疏运能力和货源—成本等因素,从全国尺度识别出“中欧班列”组织的枢纽城市。     

水氯镁石脱水反应的热力学计算

水氯镁石脱水制备无水氯化镁是一个多反应的复杂过程,文中对水氯镁石脱水制备无水氯化镁过程中可能存在的化学反应的热力学各函数进行了计算,对脱水反应机理进行探讨,并为生产提供理论依据     

A simulation system of seismogeny, occurrence and development of earthquakes

A personal computer processing system for simulation of earthquake seismogeny, occurrence and development is given in this paper. It can automatically process the discontinuous events such as earthquake occurrence during computation. The program can be paused when you want to display the computation results. After you analyze these graphical results the simulation process can be continued.     

由盐湖卤水合成球形纳米硅酸镁锂

用青海柴达木盆地的盐湖卤水为原料,经浓缩后用水热法直接合成球形纳米硅酸镁锂,此方法充分利用了盐湖资源,无需镁锂分离。同时对样品进行了X-ray、TEM表征、计算了比表面积和粒径。     

考虑SSI效应的设圈梁构造柱农村民居振动台试验研究

将参数化建模的方法引入减震结构的分析与设计中,通过预设目标和迭代优化计算,以天水市某高层住宅消能减震结构为例,寻找最优的阻尼器布置方案。为评估和验证该消能减震结构的抗震性能,分别采用Perform 3D和ETABS等软件分析结构在多遇和罕遇地震作用下的结构响应,分析结果表明：小震作用下,消能减震结构的楼层位移、层间位移角、楼层弯矩及楼层剪力均减小6.5%以上,达到了设计要求;大震作用下,结构框架柱、框架梁、剪力墙和阻尼器能够满足既定的性能要求,层间位移角满足规范限值,能够达到“大震不倒”的设计目标,研究结果为实际工程预设减震目标和阻尼器优化布置提供参考。     

非离子聚合物稳定水敏岩层的应用研究

水敏岩层机械破碎出露的新鲜岩面遇水侵蚀产生软化或泥化现象,致使孔(槽)壁变形量增大而失稳。实验表明,低聚合度、非离子型、结晶性好的高分子聚合物无固相稳定液,能以较快的竞争吸附速度在岩石的内、外表面产生渗析胶结和吸附胶结,并在不可逆的作用力下成膜,因而能抑制由水引起的岩石软化、泥化和崩解,可用以解决使用各类泥浆自由水滤失量大且泥皮易脱落而造成的孔(槽)壁坍塌问题。