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排序方式: 共有395条查询结果,搜索用时 93 毫秒
211.
212.
Assessment of groundwater chemistry in a coastal region (Kunsan, Korea) having complex contaminant sources: a stoichiometric approach 总被引:1,自引:0,他引:1
Kangjoo Kim Natarajan Rajmohan Hyun Jung Kim Gab-Soo Hwang Min Joe Cho 《Environmental Geology》2004,46(6-7):763-774
Groundwater chemistry in a coastal region (Kunsan, Korea) having complex contaminant sources was investigated. Water analysis data for 197 groundwater samples collected from the uniformly distributed sixty-six wells were used. Chemical analysis results indicate that groundwaters show wide concentration ranges in major inorganic ions, reflecting complex hydrochemical processes. Due to the complexity of groundwater chemistry, the samples were classified into four groups based on Cl and NO3 concentrations and the processes controlling water chemistry were evaluated based on the reaction stoichiometry. The results explained the importance of mineral weathering, anthropogenic activities (nitrification and oxidation of organic matters), and Cl-salt inputs (seawater, deicer, NaCl, etc.) on groundwater chemistry. It was revealed that mineral dissolution is the major process controlling the water chemistry of the low Cl and NO3 group (Group 1). Groundwaters high in NO3 (Groups 2 and 4) are acidic in nature, and their chemistry is largely influenced by nitrification, oxidation of organic matters and mineral dissolution. In the case of chloride rich waters (Group 3), groundwater chemistry is highly influenced by mineral weathering and seawater intrusion associated with cation-exchange reactions. 相似文献
213.
214.
Holographic interferometry has been applied in various fields of science and engineering. One of the most important functions of the technique is the capability of measuring displacement of any surface with a high accuracy without emplacing any gauges. In this study, the real-time technique of holographic interferometry was utilized as a new creep-testing method of rock and coal. Shale, sandstone and coal specimens were collected from the Alabama coal mines, and they were tested on a specially designed three-point loading apparatus. The results showed that the relationship of creep deflection vs. time generally followed the classical form of creep, and it varied according to physical conditions of the rock and coal specimens. This study proved that the new method can be successfully applied to the study of time-dependent behaviour of rock and coal with a high resolution and a low cost. 相似文献
215.
In search for a suitable and fast analytical method for assessing kinds of activated carbon for water purification there were carried out investigations with hydrogen peroxide. According to their catalytic activity, the various kinds of activated carbon are capable of decomposing hydrogen peroxide to different degrees and at different rates. The released oxygen can be determined volumetrically. The results of investigation obtained on always fresh carbon samples with acid and basic groups were discussed on the basis of the velocity constants of the oxygen development. An assessment of quality would be possible, in principle, but the surface characteristic of the kinds of carbon is considerably superimposed by influences of morphology, so that applying this method is advised against. 相似文献
216.
Summary The response of climate processes to changes in aerosols is investigated using a two-dimensional zonally-averaged climate model. To account for the spatial and temporal heterogeneities of aerosol distributions, a strongly scattering maritime aerosol over ocean and a strongly absorbing rural aerosol over land are used in the layer between the surface and the 700 mb level. The effects of aerosols, gases and clouds on the radiative transfer are computed concurrently using a parameterized form of a two-stream approximation. Aerosols induce a reduction of the solar absorption at the surface and an enhancement of atmospheric absorption. The resulting changes in the climate model parameters are not only a function of the radiatively-active atmospheric constituents, but also of the amplifying or dampening effects of feedback processes employed in the model calculations. For the specified aerosol types and the optical thickness distribution given by Potter and Cess, the annual temperature change at the surface is –2.1 °C with ice-albedo feedback. Without ice-albedo feedback the corresponding value is –1.4 °C. In the present study aerosols produce a cooling effect in the atmosphere at all latitudes.
With 7 Figures 相似文献
Zusammenfassung Der Einfluß von unterschiedlichen Aerosolen auf Klimaprozesse wird mit Hilfe eines zweidimensionalen Klimamodells untersucht. Um die zeitliche und räumliche Variabilität von Aerosolverteilungen zu berücksichtigen, wird über dem Meer ein überwiegend streuendes Aerosol und über Land ein überwiegend absorbierendes Aerosol in der Schicht zwischen dem Erdboden und dem 700 mb Niveau betrachtet. Der Einfluß von Aerosolen, Gasen und Wolken auf den Strahlungstransport wird mit Hilfe einer parametrisierten Zweistromapproximation berechnet. Aerosole verursachen eine Reduzierung der solaren Absorption an der Erdoberfläche und eine Verstärkung der atmosphärischen Absorption. Resultierende Änderungen der Klimamodellparameter sind nicht nur eine Funktion der strahlungsaktiven atmosphärischen Bestandteile, sondern auch von verstärkenden oder dämpfenden Rückkopplungsprozessen. Für die hier benutzten speziellen Aerosoltypen und die Verteilung der optischen Dicke nach Potter and Cess ergibt sich eine Änderung in der Jahresmitteltemperatur von –2,1 °C unter Berücksichtigung des Eis-Albedo-Rückkopplungseffekts. Ohne diesen Mechanismus beträgt die entsprechende Temperaturänderung –1,4 °C. In der Atmosphäre ergibt sich ebenfalls eine Temperaturabnahme in allen Breiten.
With 7 Figures 相似文献
217.
Jung Hoo Lee Donald R. Peacor Daniel D. Lewis Robert P. Wintsch 《Contributions to Mineralogy and Petrology》1984,88(4):372-385
Phyllosilicates in rocks which are transitional from mudstone to slate from Lehigh Gap, Pa., have been studied by a variety of techniques, including high resolution Transmission Electron Microscopy and Analytical Electron Microscopy. The principal minerals are white mica which is transitional from illite in mudstone to ordered twolayer mica in slate, and chlorite. 7Å berthierine occurs more rarely. Dioctahedral and trioctahedral layers are shown to be interleaved in individual crystals at all scales between the following two end members: (1) both random and regular 11 interlayering at the scale of individual layers, as shown, in part, by lattice fringe images. (2) packets of trioctahedral and dioctahedral layers up to a few thousand Ångstroms or microns in thickness, detectable with ordinary optical techniques. The complete range of intermediate structures is represented in samples which are in transition to slate. Bulk analytical (EMPA), X-ray diffraction or other measurements are shown to result in averages over both kinds of layers when TEM techniques are not used.Contribution No. 400 from the Mineralogical Laboratory, Department of Geological Sciences, The University of Michigan 相似文献
218.
畜禽废弃物集运车自动监控回报地理信息系统之开发 总被引:1,自引:0,他引:1
本研究能藉由装置于畜禽废弃物集运车之重量感测系统(Weighing System,WS)及全球卫星定位系统(Global Positioning System,GPS),经由全球行动无线通讯系统(Global System for Mobile Communication,GSM)全天候将集运车上畜禽废弃物载重变化及其位置,实时传回监控中心之地理信息系统(Geographic Information System,Gis)与数据库服务器中,再利用网络地图服务器经因特网(Intemet)随时提供客户端上网浏览查询与监控集运车可能不当流用之行为。本系统着重以重量变化信息作为监控端参考的重要依据,再配合车辆定位信息以核对畜禽废弃物卸载地点与重量而掌控不当流用之明确证据。另考虑集运车司机可能利用下班时间进行违法行为,监控人员无法全天侯监控,本研究系统增加集运车于非上班时间发生异常状况时,以简讯(Short Message)及电子邮件(E-mail)型式传送至预设监控者手机或远程计算机内或在提供监控者于下班时间直接透过因特网浏览器监控之功能,以及藉由远程操控软件(Symantec PC Anywhere)透过远程计算机进入监控中心做不定时的查询监视。另外,本系统透过手持式输入设备,将清运司机所输入毙死畜禽数量信息传送到GSM/GPRS(General Packet Radio Service)模块,并发送回监控端,其监控人员可透过因特网浏览接口,了解集运车辆实时清运数量、重量与路线位置之关系,以确实达到集运车辆控管之目的。 相似文献
219.
Mi Jung Lee Jong Ik Lee Soon Do Hur Yeadong Kim Jacques Moutte Elena Balaganskaya 《Lithos》2006,91(1-4):250-261
The Sr, Nd and Pb isotopic compositions for the Kovdor phoscorite–carbonatite complex (PCC), Kola Peninsula, NW Russia, have been determined to characterize the mantle sources involved and to evaluate the relative contributions of a plume and subcontinental lithospheric mantle in the formation of the complex. The Kovdor PCC is a part of the Kovdor ultramafic–alkaline–carbonatite massif, and consists of six intrusions. The initial isotopic ratios of the analyzed samples, calculated at 380 Ma, display limited variations: εNd, + 2.0 to + 4.7; 87Sr/86Sr, 0.70319 to 0.70361 (εSr, − 12.2 to − 6.2); 206Pb/204Pb, 18.38 to 18.74; 207Pb/204Pb, 15.45 to 15.50; 208Pb/204Pb, 37.98 to 39.28. The Nd and Sr isotope data of the Kovdor PCC generally fit the patterns of the other phoscorites and carbonatites from the Kola Alkaline Province (KAP), but some data are slightly shifted from the mixing line defined as the Kola Carbonatite Line, having more radiogenic 87Sr/86Sr ratios. However, the less radiogenic Nd isotopic compositions and negative Δ7/4 values of Pb isotopes of the analyzed samples exclude crustal contamination, but imply the involvement of a metasomatized lithospheric mantle source. Isotopic variations indicate mixing of at least three distinct mantle components: FOZO-like primitive plume component, EMI-like enriched component and DMM-like depleted component. The isotopic nature of the EMI- and DMM-like mantle component observed in the Kovdor samples is considered to be inherited from metasomatized subcontinental lithospheric mantle. This supports the previous models invoking plume–lithosphere interaction to explain the origin of the Devonian alkaline carbonatite magmatism in the KAP. 相似文献
220.
Ki Young Kim Jung Mo Lee Wooil Moon Chang-Eob Baag Heeok Jung Myung Ho Hong 《Pure and Applied Geophysics》2007,164(1):97-113
In order to investigate the velocity structure of the southern part of the Korean peninsula, seismic refraction profiles were
obtained along a 294-km WNW-ESE line and a 335-km NNW-SSE line in 2002 and 2004, respectively. Seismic waves were generated
by detonating 500–1000 kg explosives in drill holes at depths of 80–150 m. The seismic signals were recorded by portable seismometers
at nominal intervals of 1.5–1.7 km. Separate velocity tomograms were derived from first arrival times using a series expansion
method of travel-time inversion. The raypaths indicate several mid-crust interfaces including those at approximate depths
of 2–3, 15–17, and 22 km. The Moho discontinuity with refraction velocity of 7.8 to 8.4 km/s has a maximum depth of 37–39
km under the southern central portion of the peninsula. The Moho becomes shallower as the Yellow Sea and the East Sea are
approached on the west and east coasts of the peninsula, respectively. The depth of the 7.6 km/s velocity contour varies from
29.4 km to 36.5 km. The discrepancy in depth between the seismological Moho and the interpreted critically refracting interface
may result from the presence of a gradual transition between the crust and mantle. The velocity tomograms show particular
crustal structures including (1) the existence of an over 70-km wide low-velocity zone centered at 6–7 km depth under the
Okchon fold belt and Ryeongnam massif, (2) existence of high-velocity materials under the Gyeongsang basin, and (3) the downward
extension of the Yeongdong fault to depths greater than 10 km. 相似文献