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11.
互动式教学模式以培养学生学习的自主意识和创新能力为目标,既发挥教师的主导作用,又充分体现学生的认知主体作用。摄影与航空摄影是遥感科学与技术专业的专业基础课程,本文提出了针对该课程的互动式教学模式,并进行了课堂教学实践,总结了该模式的创新点和应用价值。 相似文献
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Cusp formation was continuously monitored on a manually flattened, plane section of a coarse clastic, microtidal, pocket beach on the Pacific coast of Japan using a CCD camera suspended in the air. Vertical video pictures enabled the examination of the temporal change in foreshore morphologies and swash pattern. Boulders on the beach face appeared to have triggered the formation of beach cusps, which gradually and successively grew up alongshore. In 2·5 h, two well defined beach cusps had developed with a spacing of 2·2 and 2·5 m, respectively. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
15.
Researchontemporalandspatialdistribu┐tion,evolutionarycharacterandmechanismofcrustaldeformationfieldbeforeandaftertheTangshan... 相似文献
16.
华英敏 《中国科学院上海天文台年刊》2002,(1)
在SCOUNIX环境下开发实时系统 ,不仅可以利用UNIX的多任务特性 ,建立起高效可靠的系统 ,而且软硬件成本较低 ,还能享有商业软件的技术服务。介绍了基于SCOUNIX环境开发实时通信系统时多路串行通信技术及UDP网络通信技术的应用 ,同时介绍了在系统中如何建立数据日志及监视进程活动 相似文献
17.
During the 2000 eruption at Miyakejima Volcano, two magmas with different compositions erupted successively from different craters. Magma erupted as spatter from the submarine craters on 27 June is aphyric basaltic andesite (<5 vol% phenocrysts, 51.4–52.2 wt% SiO2), whereas magma issued as volcanic bombs from the summit caldera on 18 August is plagioclase-phyric basalt (20 vol% phenocrysts, 50.8–51.3 wt% SiO2). The submarine spatter contains two types of crystal-clots, A-type and A-type (andesitic type). The phenocryst assemblages (plagioclase, pyroxenes and magnetite) and compositions of clinopyroxene in these clots are nearly the same, but only A-type clots contain Ca-poor plagioclase (An < 70). We consider that the A-type clots could have crystallized from a more differentiated andesitic magma than the A-type clots, because FeO*/MgO is not strongly influenced during shallow andesitic differentiation. The summit bombs contain only B-type (basaltic type) crystal-clots of Ca-rich plagioclase, olivine and clinopyroxene. The A-type and B-type clots have often coexisted in Miyakejima lavas of the period 1469–1983, suggesting that the magma storage system consists of independent batches of andesitic and basaltic magmas. According to the temporal variations of mineral compositions in crystal-clots, the andesitic magma became less evolved, and the basaltic magma more evolved, over the past 500 years. We conclude that gradually differentiating basaltic magma has been repeatedly injected into the shallower andesitic magma over this period, causing the andesitic magma to become less evolved with time. The mineral chemistries in crystal-clots of the submarine spatter and 18 August summit bombs of the 2000 eruption fall on the evolution trends of the A-type and B-type clots respectively, suggesting that the shallow andesitic and deeper basaltic magmas existing since 1469 had successively erupted from different craters. The 2000 summit collapse occurred due to drainage of the andesitic magma from the shallower chamber; as the collapse occurred, it may have caused disruption of crustal cumulates which then contaminated the ascending, deeper basalt. Thus, porphyritic basaltic magma could erupt alone without mixing with the andesitic magma from the summit caldera. The historical magma plumbing system of Miyakejima was probably destroyed during the 2000 eruption, and a new one may now form.Editorial responsibility: S Nakada, T Druitt 相似文献
18.
乌干达Albert湖凹陷是世界上最年轻的生烃凹陷,受构造和沉积控制,油气多分布于北部构造调节带。为分析Albert湖北部构造调节带内部油气成藏特征,笔者利用地震、钻井、测井和孢粉等资料,开展北部构造调节带沉积特征研究,进而分析北部构造调节带的油气成藏模式。研究表明,由于边界正断层持续活动,北部构造调节带两侧沉积特征存在差异,研究区西部发育曲流河-三角洲沉积体系;东部发育冲积扇-扇三角洲沉积体系。由于北部构造调节带西部三角洲砂体向南推进至湖盆中心,与深湖相烃源岩直接沟通,成为Albert湖盆最有利的油气汇聚区。 相似文献
19.
The stability of a simple coupled ocean-atmosphere system similar to the one studied by Hirst with general ocean thermodynamics
is investigated in which the atmospheric heating is determined by sea surface temperature anomalies as well as the convergence
feedback (low level moisture convergence by the waves themselves). It is shown that the unstable coupled mode found by Hirst
(UH mode) is profoundly modified by the convergence feedback. The feedback increases the unstable range of the UH mode and
can increase its growth rate several folds. The maximally growing UH mode can become westward propagating for certain strength
of convergence feedback. If the convergence feedback strength exceeds a critical value, several new unstable intraseasonal
modes are also introduced. These modes are basically ‘advective’ modes. For relatively weak strengths of the convergence feedback
the growth rates of these modes are smaller than that of the UH mode. As the atmosphere approaches ‘moist neutral’ state,
the growth rates of these modes could become comparable or even larger than that of the UH mode. It is argued that these results
explain why the El Nino and Southern Oscillation (ENSO) signal is clear in the eastern Pacific but not so in the western Pacific
and they may also explain some of the differences between individual ENSO events. Our results also explain the aperiodic behaviour
of some coupled numerical models. Importance of this process in explaining the observed aperiodicity of the ENSO phenomenon
is indicated. 相似文献
20.
The Moon 35 years after Apollo: What's left to learn? 总被引:1,自引:0,他引:1
Clive R. Neal 《Chemie der Erde / Geochemistry》2009,69(1):3-48
With the cancellation of the Apollo program after Apollo 17 returned from the Moon in 1972, the focus of NASA switched to other areas of the Solar System. Study of the Moon did continue through analysis of the returned samples and remotely sensed data sets (both orbital and surface), as well as through Earth-based telescopic studies. In the 1990s, new orbital data were obtained from several missions (fly-by and orbital), the first being Galileo that allowed the lunar farside to be mapped, followed by global mapping by the Clementine and Lunar Prospector missions.Interest in the Moon started to increase at the beginning of the 21st century as other nations focused their space exploration programs on the Moon. The speech by President Bush in January 2004 put the Moon back into the critical exploration path for NASA, paving the way for humans to return to the lunar surface by 2020. This return will be critical for developing technologies and protocols for the eventual human exploration of other parts of the solar system. At the time of writing (June 2008), the SELENE/Kaguya mission (Japan and Chang’e-1 (China) are orbiting the Moon, with Chandrayaan-1 (India) and Lunar Reconnaissance Orbiter (USA) being scheduled to launch later in 2008.The past (and present) exploration of the Moon begs the question “what's left to be done?” With the renewed focus on the Moon, now that it is on the pathway for the exploration of Mars (and beyond) a similar question has been raised - what should the astronauts do on the Moon? The publication of the New Views of the Moon book [Jolliff et al., 2006. New Views of the Moon, Reviews in Mineralogy, vol. 60. American Mineralogical Society, 721pp] highlighted a number of important scientific questions that remain unanswered as well as posing many more on the basis of the currently available data. These questions resonated in three Lunar Exploration Analysis Group (LEAG) reports pertinent to this discussion, which were also published (on line) during 2006 (http://www.lpi.usra.edu/leag), and in the National Research Council of the National Academies [2007. The Scientific Context for Exploration of the Moon. National Academies Press, Washington, DC, 112pp] report entitled “The Scientific Context for Exploration of the Moon”. This paper synthesizes these recent studies, along with those from the 1980s and 1990s, to emphasize the lunar science questions that remain unanswered. In addition, it summarizes the missions already flown to the Moon along with those that are planned in order to give the reader an idea of exactly what lunar science has been and will be conducted in the hope that it will inspire proposals for missions to address the outstanding science questions. 相似文献