高温高压下煤变形的实验分析

通过对不同温度、压力实验条件下,不同煤级煤的应力－应变曲线特征分析,探讨了不同煤化程度煤的变形行为及其影响因素,论述了温度和压力在不同煤级和不同实验条件下具有的不同作用。在中煤级阶段,虽然围压的增大可在一定程度上提高煤的强度,但温度的影响更为重要。较高煤级在小应变阶段,温度起主导作用;而到了大变形阶段,围压的作用又逐渐上升到主导地位。此外,在一定的条件下,煤中气体的产生和释放对煤的变形行为具有显著     

夕卡岩矿床研究的某些重要新进展

夕卡岩矿床是一种具有重要工业意义的矿床类型，是世界上富铁矿，钨、锡、铋、铅锌，金和金云母，透辉石，硅灰石等金属和非金属矿产的重要来源。这类矿床不仅分布广泛，矿物组合特殊，而且包含有内生成矿作用许多复杂的成因信息。因此，一个多世纪以来国际上对夕卡岩矿床的研究长盛不衰，不断有所创新，文章回顾了近二十年来，在成矿的构造背景，矿床的多成因性，岩浆期和岩浆夕卡岩，碱交代与成矿，交代分带，含银铅锌锰质夕卡岩，含金夕卡岩和夕卡岩含矿性评价标志等方面新的研究进展。     

The San Dimas experimental forest: Hydrologic research in semiarid steepland terrain

The San Dimas Experimental Forest (SDEF) is located in southern California and is representative of the chaparral shrublands of the Southwest USA. Chaparral – including genera of Ceanothus, Adenostoma, Quercus, Salvia and Arctostaphylos – is a dense, drought-tolerant vegetation assemblage with a closed canopy 3–5 m in height. Chaparral is a fire-prone ecosystem and wildfires have burned the SDEF about every 40 years. The SDEF was established in 1933 to quantify the water cycle in a steep, semiarid landscape. Study catchments range in size from 15 to 1160 ha and measurements of stream runoff are made in a nested weir and flume arrangement to account for the very flashy flows. Apart from native chaparral vegetation, streamflow measurements in these study watersheds have also quantified the hydrologic response of vegetation type-conversion and fire. Innovations in hydrologic monitoring developed on the SDEF include a critical depth flume (the San Dimas flume) and tilted rain gages to better sample precipitation in mountainous terrain. Subsurface runoff and plant water relations have been measured in a large lysimeter complex. Water quality monitoring shows that stream water in the SDEF has very high levels of nitrate, derived from atmospheric deposition of chronic air pollution, that approach the Federal EPA standard of 10.0 mg L⁻¹ for nitrate-N. Spreadsheets of rainfall and streamflow (from 1938 to 2015) – the San Dimas Experimental Forest hydrologic database – may be found at the right-hand side of the web page at https://www.fs.fed.us/psw/ef/san_dimas/index.shtml . Hard copy charts, tables and other records associated with the foregoing data streams are available from the USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, California, 92501 USA or at pete.wohlgemuth@usda.gov .     

Census 2000 and Geography Education

Abstract

By using stream restoration as a seminar theme, geography faculty can create a topical course that helps provide a shared intellectual agenda for both physical and human geography students, while highlighting the holistic strengths of our discipline. Although it is not necessary that faculty have prior knowledge about the topic, a willingness to work collaboratively is essential to creating an effective course about this complex endeavor. The course can simultaneously meets the needs of students continuing on to graduate studies as well as those preparing for teaching careers. Guidance on how a stream restoration class could be used to teach the eighteen geography standards is also provided.     

Shared Learning: Feminist Student Research on Household Reuse Behavior

Abstract

This paper describes collaborative student research on waste management that first compiled home interviews with women professors in Oxford, Ohio, USA, and Beijing, China, on household reuse for a graduate thesis and then communicated the findings in a handbook for undergraduate students. The women participants described diverse household reuse activities and important differences in how items enter and leave their homes. Reuse behaviors were derived intuitively from local contexts but could also be learned through cross-cultural education. These projects show positive links between feminist research and pedagogy in geography that encourage shared learning and promote women's contributions to environmental conservation.     

Overcoming Geographic Innocence in Geography Education

Abstract

This article deals with the issue of providing geographic training to prospective teachers from the perspective of a secondary school teacher who also teaches a social studies methods course. Research in educational journals provided a background for describing the lack of geographic training among social studies teachers. While the National Geographic Society's alliance network is addressing this issue among practicing teachers, there is still a need to include some geography training for preservice teachers. Suggestions are offered for including geography within the context of the social studies methods course. A plea is also made for geography professors to include the new National Geography Standards in their courses, especially in introductory courses.     

Co-Mingling Geographic Education with Social Studies Methods

Abstract

Most preservice teachers complete their social science course requirements in isolation from their social studies methods course. This paper reports the unique co-mingling of one interdisciplinary social science course (emphasizing geographic and environmental education) with the social studies methods for a cohort of undergraduate preservice teachers. Integrating parts of their curricula, instruction, assignments, and assessments through a co-mentoring process and action research project connected professors and preservice teachers with children and their environments. A review of the professors' process accompanied by a summary of preservice teachers' projects and reactions describes the classroom experiences and pedagogical outcomes experienced by each group.     

The Weavers of the “Western Isles”

This study provides an in-depth investigation of Turkish primary school students’ perceptions of geography. Gender differences in students’ perceptions of geography were investigated, including definitions of geography and its field of study. The findings showed that landforms, our geographical regions/Turkey, mapwork, and countries dominated among students’ definitions. Geography topics cited were mainly within the physical geography category and mostly those of landforms and cartography. A chi-square test revealed a statistically significant difference between girls and boys in the Turkey category and the history-related issues category.     

岩质滑坡的时间预报与水力启动模型

摘 要 岩质滑坡发生时间的适时超前预报是一个世界性难题,之所以长期不得其解,主要是缺乏对滑坡成生机理的明晰认识和未建立正确的量化模型。本文根据我国长江三峡工程库岸和西南山区积累的大量滑坡实例调查资料并参考国外的一些研究成果,排除了地形控制论与地层控制论观点,阐明了滑坡形成的必要条件是斜坡具有易滑结构;滑坡发生的充分条件是有一定强度的诱发因素作用。故而诱发因素的动态变化对滑坡发生的时间具决定意义。 鉴于地下水诱发的岩质滑坡分布最广,为建立正确的水力启动模型,本文归纳了近代典型岩质滑坡的主要特征:（1）滑面是导水性差异最大的贯通面;（2）滑体长度大而厚度小,长厚比多在20左右;（3）滑坡前缘段先启动;（4）临滑前在前缘段有渗水、冒水或喷水现象;（5）出水宽度之和远小于前缘段总宽度。根据这些特征和水力学、水文地质学的成熟理论指出jennings（1970）等人提出的岩质斜坡稳定性模型存在下列问题:（1）未表明贯通面上岩体重力分布状况;（2）空隙水压力的分布特征与前述滑坡现象和水力学原理相悖;（3）未考虑通水率问题。然后,本文按顺向坡中的易滑超倾坡和椅状坡两个类型建立了斜坡稳定性模型和滑坡水力启动临界值（基本）计算公式。提出潜滑面的综合内摩擦角和通水率的确定方法:（1）滑坡反算;（2）对无水压滑坡滑面倾角和渗水边坡通水率进行观测统计;（3）剪切试验和简易水文地质试验;（4）物探方法。 本文还讨论了新模型的实用意义和应用范围,并对解决这类复杂地质灾害问题的研究途径发表了作者的认识,强调了积累经验的重要性。