随着MOOC、SPOC等线上线下混合教学的发展,我国高校的在线教学水平得到提高.但是,由于线上教学平台的功能、教师信息化能力、学生适应性等均存在差异,所以目前的在线教学还面临着教学缺乏临场感、师生缺乏互动、线上教学考核机制不完善以及学生的注意力容易分散、无法通过集体学习相互交流促进、学习缺乏监督等急待解决的问题.为了解决在线教学面临的困难,提高在线教学效果,以"土木工程测量"课程为例,开展了线上教学的改革探索.一是认真进行学情分析,积极重构线上课程教学体系,结构串讲注重精讲适当留白,调动学生学习的内在动机;充分利用线上教学平台,指导学生完成练习任务;组织在线合作学习和讨论,引导学生深入学习;开展直播答疑和总结,提升学生线上学习质量.二是根据线上教学特点,通过设计线上课程教学6个环节的脚本和3个阶段的教学方案、以五星教学法组织线上课程教学的方案、线上课程教学中教师所承担的3种角色、线上课程教学平台5种信息化教学工具的使用等,优化和完善课程教学设计方案.三是以直播教学资源建设为重点,通过签到、提问、投票、小测验等在线教学平台提供的小工具强化对学生学习过程的调控和管理,使教学内容不仅具有完整性、丰富性和系统性等特点,而且适合线上教学平台传播、符合学生线上自主学习认知规律特点.四是遵循"以评促学"主导思想,设计全方位覆盖"课前、课中、课后"的"过程性考核评价体系",为线上课程教学质量提供保障.

翻转课堂混合教学模式是一种通过改变、逆转教学结构的方式以提高教学效率与教学质量的创新教学模式,这种教学模式可以促进学生能力的全面发展.在测量学课程教学实践与教学改革过程中逐步建立了操作性强的混合教学对策;并通过挖掘对策的理论依据形成翻转课堂符合实际的混合教学设计模式的10个关键步骤;运用四步结构法组织测量课程的教学;建立与混合教学模式相匹配的评价体系.以期形成的教学对策、教学设计模式、四步结构教学法和教学评价体系对改变教学模式和提升教学质量提供现实意义.通过对测量学在混合教学模式实践中取得的成就及尚待解决的问题进行总结反思,以期对其它课程应用混合教学模式有现实指导意义,进而有助于混合教学模式的推广应用.

In order to analysis the landscape layout of north campus, south campus and the whole campus, discuss the advantages and disadvantages of the current landscape layout and provide a basis for future campus pattern, this paper put the nwsuaf CAD-campus plan and HD remote sensing image as the basic data, combined with topographic map of Yangling District, made use of the unique methods of landscape pattern and used Landscape Ecology-related indicators to analysis the North-South Campus land use and landscape pattern distribution. The results show that: ①Each landscape fragmentation in the South Campus is greater than that in the North South, the advantage of the North Campus buildings are higher than the North Campus; ② On school-wide perspective, the living facilities landscape, the green landscape and the recreational amenities landscape respectively have the greatest diversity, evenness, dominance. Evenness of the recreational amenities landscape is the lowest. Advantage of the green landscape is the least. ③ Building facilities (including teaching, living, entertainment, ancillary facilities) in the South Campus play a greater dominant role to landscape, the human factors have a greater influence on landscapes in the South Campus, such as cutting the green landscape, the multi-vegetation road landscape, recreational amenities landscape to achieve a harmonization of green and leisure. In a word, the entire campus has a reasonable landscape spatial pattern and harmonized functional zones.

Principles of forest ecosystem stability are fully analyzed and discussed from the angle of changeability of ecological components,reaction to disturbance,pattern of nutrients storage and flux and recycle of nutrients in forests.Meanwhile,four artificial forest ecosystems,including Robinia pseudoacacia,Larix gmelinii,Pinus tabulaeformis and Cunninghamia lanceolata,are studied typically about their nutritional conditions and stabilities.It shows that the four forest ecosystems take obtuse form as their main storage of nutrient.The amounts of N,P,K,Ca and Mg stored in soil take up more than 92% respectively of the responding storages of the total forest ecosystem.Further more,the nutrients in the soil retains balance or show slight deficit,whereas,the nutrients in the total forest ecosystems happen to slight surplus or retain balance.In addition,compared with others,the forest of R.pseudoacacia is one of high nutrient absorption,high returning,fast recycling and nutrient wasting,and due to the faster recycling of nutrient,the forest of R.pseudoacacia will have strong capability of restoration in case of minimal disturbance but be irretrievable under serious disturbance.Finally it is suggested that the biogeochemical classification of forests would be an important approach to study the functional stability of forest ecosystem.

针对传统的农村土地管理方式的不足与缺陷,结合G IS技术、计算机技术及测绘技术,设计了基于MAPG IS的农村土地管理信息系统,对系统目标、系统的软硬件环境、系统总体结构及系统总体功能进行了分析设计。并以杨陵李台乡为例,对农村各类土地信息进行空间查询统计分析、动态分析,为土地管理提供准确、可靠且直观的数据。

针对传统的农村土地管理方式的不足与缺陷,结合GIS技术、计算机技术及测绘技术,设计了基于MAPGIS的农村土地管理信息系统,对系统目标、系统的软硬件环境、系统总体结构及系统总体功能进行了分析设计.并以杨陵李台乡为例,对农村各类土地信息进行空间查询统计分析、动态分析,为土地管理提供准确、可靠且直观的数据.

Although the traditional term ecosystem has provided us an explanatory framework for ecological phenomena, with the deepening of its application, the ambiguities of this concept are becoming more and more apparent and leading to a vigorous backlash and question toward it. The backlash and question focuses on the spatial closure, spatial homogeneity and Latin binomial substitute ability, which the traditional ecosystem concept has assumed. It also involves the natural selection minimized or ignored, scaled concept of stability and dispersal range of species. According to the fact, the ecosystem is spatial open and internal heterogeneous. Natural selection is one of the important processes that determine system stability. The concept of ecosystem, which is defined strictly in terms of function but minimizes the role of Latin binomials, ios not adequate to be a general theory of ecological phenomena. In other words, an adequate theory of ecosystem must be able to deal with stability, which represents a fundamental phenomenon to be explained. So, to realize critically the ecosystem concept and then to improve and optimize it certainly seems to be an important target of ecology in future.

森林生态系统中,初级生产者和分解者之间的养分关系,是一种既互利又竞争的复杂关系.通过构建初级生产者-分解者系统的养分流动模型,分析分解者增长受碳限制或受养分限制的判断标准.在假定整个系统封闭的前提下,讨论初级生产者与分解者实现共存并保持长久稳定的条件:一是分解者必须受碳限制,这要求分解者较之初级生产者对养分吸收具有更强的竞争力;二是矿化系数与碎屑化系数之比(a41/a23)要足够大于在初级生产者中的碳/养分与在分解者中的碳/养分之比(α/β).这表明,从化学计量论的角度来看,生态系统的持续和稳定,对碳/养分之比和植物与微生物的竞争能力方面有严格的要求.

黄土残塬区的沟道由于地质地貌基础及土壤侵蚀强度的不同而具有不同的形态特征.按沟道开析状况可将沟道划分为开析型、半开析型和深切型,按地面割裂程度可划分为强度割裂型、中度割裂型和弱度割裂型,按主支沟状况可划分为主沟型、半主沟型和支沟型.沟头从发生学角度可划分为原生侵蚀沟头和次生侵蚀沟头两类,从目前的发育程度和活跃状况可划分为顶极型、遏止型和前进型沟头.对不同类型的沟道和沟头提出了积极的防治建议.

该文从终身环保教育的概念及内涵入手,阐述了建立终身环保教育体系的构想,非常有现实借鉴意义.

本文从生态系统可持续性的内涵和基本构成两个方面探讨了生态系统可持续性的基本原理,同时就发展持续林业的趋势、结构、特点和理论基础等问题进行了详尽地论述.

As a type of forest resource with largest distribution and quantity of Gullied Loess Plateau Area, black locust plays an irreplaceable role in ecological environment protection. However, the current situation is not optimistic, that is, many Black, locust stands on bad site take weak sign and form due to poor management, which results in low-yielding forest and even little old man forest with annual growth less than 1m~(3)/hm~(2). Traditional way to deal with this is to raise foerst productivity throught short-cycle cutting. But this is not a reliable method, for repeated regeneration of one tree species may cause the problem of soil nutrition imbalance, which leads to low growth of germinated plantation and not beneficial to the cultivation of thick timber, Therefore two more effective methods can be adopted: Fistly, to fertilize to further prolong soil fertility and keep it from degeneration; Secondly, to introduce renewed species in ways of mingle or rotation. Accordingly, a thorough and deep know ledge is required of nutrition situation in black locust forest so as to provide sciencetific basis for the determination of fertilizating plans and renewed species.

The fundamental principle of ecosystem sustainability, including its intension and construction, was ana-lized in this article. Meanwhile, many problems about sustainable forestry, including its tendency, construction, characteristics and theoretical basis were discussed in details.

以野外实地测量为主,图上量算为辅的方法,对我国西部绿色硅谷-杨凌农科城的园林绿地进行了调查.结果表明,杨凌城区园林绿地面积142 hm2,绿化覆盖率为27.7 % ,略大于全国平均水平(25.53 %),但小于全国12 个园林城市平均水平(36.07 %).人均占有绿地面积21.1 m2,但大都属于机关附属绿地,而公共绿地面积仍然很小.从功能类型上来看,除了城区边缘苗圃、花圃和果园等生产绿地之外(面积38.88 hm2,占27.38 %), 园林绿化还是以道路林为主(面积23.02 hm2,占16.21 %),其次为办公区绿地、住宅区绿地、游玩绿地和观赏绿地,而分车绿地和防护绿地占极少部分;从配置类型上来看,全区以间树草坪类型所占面积最大,为64.51 hm2,占绿地面积45.43 %.此外,校区绿化又以林荫树为主,非校区除了苗圃和果园之外以行道树为主.从整体结构配置上来看,建设公共绿地、风景林地、树木园和植物园以及城郊生态绿地是杨凌未来向园林城市发展的方向.

本文分析了跨越障碍物水准测量的主要误差来源,提出了减少或消除误差的几种方法,并经实地施测证明,该方法均能满足一定的精度要求,且简单实用.

测量学技术用途广泛,在国家经济建设中是一项带有基础性和为国民经济超前服务的工作.在农林业中,地形图是各项规划设计的图面资料,如荒山荒坡调查,宜林地的造林规划设计,苗圃的布局与建立;水土保持林、农田防护林的营造,渠道、水库的测设,种植园规划和土地调查等,都离不开测量技术.因此,测量学在农林行业中有着其它课程不可替代的作用.此外,测量学是一门实践性很强的专业基础课,通过学习能够培养学生的实际操作技能和独立应用知识的能力,有助于学生综合素质和创新能力的提高.

全球定位系统GPS具有路标、路线、方向、速度、导向、追踪、计算机上/下载数据和地图等功能,在水土保持综合调查、水土保持工程规划设计、水土流失动态监测和水土保持工程验收中具有广泛的用途,随着RS和GIS集成技术的深化,GPS在水土保持中的应用将更加广泛和深入.

应用MATLAB软件,对航空遥感图像进行增强处理.比较分析了直方图均衡化、线性扩展和对数曲线、指数曲线扩展方法对农耕地、果园地、林地、牧草地、工矿居民地和道路的增强效果.结果表明,利用MATLAB软件的图像处理功能,能够满足遥感图像的增强处理要求,不仅速度快,方法科学,而且可为航片的判读提供良好的条件,有助于提高判读精度.

分析了地籍信息的特征;设计了地籍测量数据库结构;提出了地籍信息分类贮存与科学管理的新途径.