Decisions of the U. S. Board of Geographic Names. June 5, 1900, To January 8, 1902 II     

《The Journal of geography》2012,111(5):213-217

ABSTRACT

Spatial literacy is a new frontier in K–12 education. This article describes a place-based introductory GIS/GPS middle school curriculum unit in which students used measuring tools, GPS units, and My World GIS software to collect physical and spatial data of trees to create a schoolyard tree inventory. Maine students completed “memory maps” of their schoolyards as a pre/post exercise assessment. A statistically significant increase in students’ spatial awareness was documented. A technology-based curriculum can significantly increase students’ spatial awareness especially in a place and context relevant to each student.  相似文献   

Determination of the 13C/12C Isotope Ratio of Organic Compounds for the Biological Degradation of Tetrachloroethene (PCE) and Trichloroethene (TCE)     

S. Ertl  F. Seibel  L. Eichinger  F. H. Frimmel  A. Kettrup 《洁净——土壤、空气、水》1996,24(1):16-21

With the method used here, it was possible to determine the isotope content of both the initial compounds and their metabolites formed due to microbial degradation. The chemical analysis showed that the dominating degradation metabolite for both PCE and TCE degradation was cis-1,2-dichloroethene (cis-1,2-DCE). Apart from this, the formation of TCE, trans-1,2-DCE, 1,1-DCE, chloroethene (VC), ethene and ethane was observed. The isotope analysis showed no measurable fractionation of stable carbon isotopes, for the microbial degradation of PCE and TCE to cis-1,2-DCE. There was a small effect for trans-1,2-DCE and a stronger one for VC as metabolite of TCE.  相似文献   

A/D转换器MAX199及其在差热天平仪改造中的应用     

涂水林 《华东地质学院学报》2001,24(3):233-236

阐述了MAX199的特性和工作原理，介绍了MCS－51系列单片机与MAX199的硬件接口设计以及软件编程方法，最后简述了该模数转换器在差热天平仪改造中的应用。  相似文献   

ZJB(BP)-30A型变频调速高压注浆泵的研制          下载免费PDF全文

崔高汉高铁军  董朝晖 《探矿工程》2001,(1):27-27,29

介绍ZJB（BP）－30A型变频调速高压注浆泵的设计思路、研制过程以及其主要技术参数和性能特点。  相似文献   

Later Pleistocene/Holocene climate conditions of Qinghai-Xizhang Plateau (Tibet) based on carbon and oxygen stable isotopes of Zabuye Lake sediments   总被引：2，自引：0，他引：2  

R.L. Wang  S.C. ScarpittaS.C. Zhang  M.P. Zheng 《Earth and Planetary Science Letters》2002,203(1):461-477

We present a time series of carbon and oxygen stable isotope records of the last 30?000 ¹⁴C years throughout the last glacial-postglacial cycle from western Qinghai-Xizhang (Tibet) Plateau. A 20-m core drilled in the south basin of Zabuye Salt Lake was analyzed for inorganic and organic carbon and total sulfur contents, δ¹³C and δ¹⁸O values of carbonates. Our results indicate that climatic changes have led to a drastic negative shift of stable isotope ratios at the transition between the Last Full Glacial and the postglacial phase during Later Pleistocene times (∼16.2 kyr BP), and a rapid positive shift at the transition from Pleistocene to Holocene (∼10.6 kyr BP). The first shift is marked by the drop of δ¹⁸O_carb values of about 10‰ (from +2 to −8‰) and δ¹³C_carb values of about 3‰ (from 5 to 2‰). The second shift which occurred at the transition from Pleistocene to Holocene was of similar magnitude but in the opposite direction. Isotope data, combined with total organic and inorganic carbon contents and the lithological composition of the core, suggest this lake was an alluvial pre-lake environment prior to ca. 28 ¹⁴C kyr BP. During ca. 28-16.2 ¹⁴C kyr BP, Zabuye Lake was likely a moderately deep lake with limited outflow. The cool and arid glacial climate led the lake level to drop drastically. Extended residence time overwhelmed the lower temperature and caused a steady increase of δ¹³C_carb and δ¹⁸O_carb values and total inorganic carbon content in the sediments. During ca. 16.2-10.6 ¹⁴C kyr BP, this lake probably overflowed and received abundant recharge from melting glaciers when the deglaciation was in its full speed. A spike of markedly enhanced δ¹³C_carb and δ¹⁸O_carb is seen at ∼11.5 kyr BP, probably due to the isotopic effects left behind by the short but severe Younger Dryas (YD) event. After ca. 10.6 ¹⁴C kyr BP, Zabuye Lake probably closed its surface outflow, due to strong desiccation and drastic climate warming. The Early and Middle Holocene were characterized by unstable climatic conditions with alternating warmer/cooler episodes as indicated by the severe fluctuations of total organic carbon, δ¹³C and δ¹⁸O values. A hypersaline salt lake environment was finally formed at Zabuye after ∼5 ¹⁴C kyr BP when the mirabilite and halite concentrations steadily increased and became the dominant minerals in the sediments. Severe imbalance of inflow/outflow resulted in the drastic increase of total sulfur, δ¹³C_carb and δ¹⁸O_carb values and dominance of halite in the lake since ca. 3.8 kyr BP to present.  相似文献   

The value of teaching about geomorphology in non-traditional settings     

R. Laurence Davis   《Geomorphology》2002,47(2-4)

Academics usually teach about geomorphology in the classroom, where the audience is enthusiastic, but generally small. Less traditional settings offer opportunities to reach a wider audience, one that is equally enthusiastic, given its love of geomorphic features in the National Parks, but one which has little knowledge of the science behind what they are seeing. I have “taught” geomorphology in four non-traditional settings: at a summer camp, a state wildlife refuge, on community field trips, and at meetings for clubs and government boards. This paper discusses my experiences and offers suggestions to others who may wish to follow this less-traveled educational path.As Head of Nature Programs at Camp Pemigewassett in New Hampshire, I have worked, over the last 33 years, with thousands of campers ranging from 8 to 15 years old. Our setting, in a glaciated valley on a small lake, exhibits a wide range of geomorphic features and offers many opportunities for direct learning through field investigations. I have found that even 8-year olds can do real science, if we avoid the jargon. Once “taught” they carry their knowledge about landforms and processes with them and eagerly share it with their friends and family on outings and trips, thus reaching an even wider public.Parks, wildlife refuges, nature preserves, and other similar areas generally have nature trails, often with educational information about the environment. Generally, interpretive signs are prepared by biologists and the content ignores the site's physical features, as well as the connections between ecological communities and the underlying geology and geomorphology. My students and I have addressed this situation at two places in Connecticut, one a state wildlife management area, also used for training teachers to teach Environmental Education, and the other, a town recreation area. We catalogued the geomorphic features, looked at relationships of the community level ecology to those features, and prepared interpretive signs that added this perspective to the trails. The public response has been extremely favorable.Geomorphology can also be taught by leading field trips for community organizations. I have done this twice, once for the Manchester (NH) Historical Society and once for a small watershed association. The attendance and interest surprised me. We finally had to limit the Manchester trip to one full busload (45) and the watershed trip, which was part of a “trails day,” drew over 90 people.Finally, I have found that organizations such as Sierra Club chapters and town conservation boards are frequently looking for speakers for their periodic meetings. Why not a geomorphologist? After all, much of what conservationists do is related to what geomorphologists do. I have given several of these presentations and the receptions have always been enthusiastic.While the work involved in preparing to teach in one of these non-traditional settings is frequently substantial, the rewards are equally large. It is a way to reach masses of people who know little about the science of geomorphology and to demonstrate its importance to them. Taking our message directly to the public in these settings is an effective way to put geomorphology in the public eye.  相似文献   

The Production and Release of CFCs from Coal Combustion   总被引：3，自引：0，他引：3  

LI Jiaxi  WANG Junzhi  LI Hong  RAO Zhu  LI Qi  LUO Songguang National Research Center of Geoanalysis  Chinese Academy of Geological Sciences  Beijing 《《地质学报》英文版》2003,77(1):81-85

The destruction of the ozone layer in the atmosphere caused by industrially synthesized CFCs has aroused greatest concerns from the international society, but the CFCs formed from burning of coal containing fluorine have not been recognized by the world yet. In the present study, we condensed the gas through cold traps and used the GC-MS to measure the gas composition, and found that the content of CFC-12 in the smog from coal combustion was significantly higher than the background value of the local atmosphere. This proves that CFC-12 is formed in the process of coal combustion. This paper discusses a new source of non-synthesized CFCs.  相似文献   

Study on diagenesis of organic matter in immature rocks     

Shi Jiyang  Wang Benshan  Zhang Lijie  Hong Zhiqing 《Organic Geochemistry》1988,13(4-6)

Since many immature oils have been found in a number of Tertiary basins of China, a series of cores (Oligocene) and several immature rocks after thermal simulation have been investigated for their biomarker distributions by GC and GC-MS. The presence of biomarkers in the cores seem to follow a rule of less to greater stability of hopenes, ββ-hopanes, diasterenes with increasing the depth of cores, and subsequently the 22R, 22S configuration of hopanes reaches equilibrium. The thermal simulation experiments with immature rocks demonstrated that it is possible to generate some immature oils from immature rocks during the diagenesis stage. The tricyclic terpanes generated from source rocks during diagenesis stage tended to be enriched in the oils compared to their source rocks and the relative abundance of lower molecular weight tricyclic terpanes to their higher molecular weight homologues may be useful for the subdivision of diagenesis.  相似文献   

链子崖危岩体T8──T12缝段开裂变形机制的研究   总被引：12，自引：2，他引：12  

刘传正  施韬 《工程地质学报》1995,3(2):29-41

文章通过对煤层采空区的分布、地压作用、山体开裂和近２０多年来的变形等方面的综合分析，得出链子崖危岩体具有南北强拉裂、东西弱拉裂和平面反时针转动的立体开裂变形机制。据此，作者进行了有针对性的计算，为危岩体综合加固体系的建立提供了依据。  相似文献   

CorelDRAW12数字化制图在物探图件中的应用     

王中海  方少华 《现代测绘》2006,29(2):46-48

随着计算机科学技术的飞速发展,计算机制图已势在必行,传统的手工制图将成为历史。在编写石油物探成果报告时,为使物探图件的制作更加精确、美观,运用CorelDRAW12可取代手工绘图快速进行计算机制图,首先绘制图廓、建立数学基础,其次制作地理底图,最后再从工作站导入石油物探图件的专题要素进行编辑,之后导出所需格式文件供其它软件使用,可满足石油物探成果报告上交归档电子版的要求,进一步提高石油物探成果报告的质量。  相似文献