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121.
Manfred Joswig 《Geophysical Journal International》1995,120(2):262-286
122.
Paul A. Knapp Judith M. Lancaster Kathleen A. Bishop Richard L. Taylor 《The Professional geographer》1993,45(3):323-331
This paper demonstrates the use of a Geographic Information System (GIS) to develop timber thinning strategies on the Kyburz Planning Area of the Tahoe National Forest in northeastern California. The primary criteria used in an assessment of selective thinning potential were forest health and fire hazard ratings. By eliminating environmentally sensitive, economically unfeasible, or low fire hazard areas from consideration, the use of GIS reduced the area that was considered appropriate for thinning by approximately 58%. GIS offers considerable potential for improving resource management strategies. 相似文献
123.
The development and first tests of a novel method for the direct, sensitive, selective, and fast detection of gaseous nitric acid in air are described. The detection method is based on the laser-photolysis fragment-fluorescence (LPFF) method using 193 nm (ArF) laser light. The photolysis process yielding OH fluorescence has been thoroughly investigated. Up to now, the method has been found to be practically free of interferences. The mixing ratio for nitric acid is measured on-line with a detection limit of about 0.1 ppbv for an accumulation time of the signal of 10–15 min. A number of tests and field measurements were performed to demonstrate the feasibility and limits of the described detection method. 相似文献
124.
小试金光谱法同时测定地质样品中超痕量铂钯金 总被引:9,自引:2,他引:9
用小试金光谱法同时测定地质样品中低至0·x×10~(-9)级Pt、Pd和Au,包括先用小试金熔炼和灰吹预富集10g样品中的Pt、Pd和Au于1mg的银合粒中,然后把银合粒装入石墨电极同锇-锑合金(ω(Os)=0.06)一起激发,以发射光谱法同时测定它们的含量。小试金法类同经典火试金,但采用纯化过的2PbCO_3·Pb(OH)_2(Pt、Pd和Au的含量皆<0.05 ×10~(-9)代替商品PbO,并且用50ml高铝坩埚在950℃进行熔炼。方法的检出限是Pt0.2×10~(-9),Pd和Au均为0.1×10~(-9)。对于3×10~(-9)的含量,全过程的相对标准偏差(%)是Pt15,Pd11,Au9。此法快速、简便,适用于地质物料的分析。 相似文献
125.
使用1980-1991年森林火灾及相应的气象资料,分析了森林火灾与有关气象要素的相关性。在此基础上,计算了森林火险天气预报指标,建立了预报模式,开展了森林火险天气等级预报。经试用效果较好。 相似文献
126.
Tree stem (>2 m tall) mortality was assessed following a late dry‐season wildfire across a seasonally flooded elevation gradient at Workshop Jungle, near Darwin, in the Northern Territory of Australia. For all species combined, dead stems had significantly smaller diameter at breast height (dbh) than living stems. Assessment of tree‐stem damage following a tropical cyclone at Cobourg Peninsula, NT, revealed that damaged stems had significantly greater dbh than undamaged stems for all tree species sampled across a boundary between monsoon rainforest and savanna. A greater proportion of stems were damaged by the cyclone than by the fire (28 per cent as against 18 per cent), although there were considerable between‐community differences in the proportion of damaged stems at the two sites. The fire caused little impact (<10 per cent) on total basal area of three different forest communities on the elevation gradient at Workshop Jungle. The cyclone was found to cause >50 per cent damage to total basal area of three different communities on Cobourg Peninsula. It is suggested that the combination of a cyclone followed by an intense fire in storm debris could potentially destroy a monsoon rainforest through its impact on all tree‐size classes. This may explain why some monsoon rainforests rapidly contracted following Cyclone Tracy that destroyed the city of Darwin on Christmas Day, 1974. 相似文献
127.
油气储运系统钢结构设备地震火灾效应研究 总被引:3,自引:0,他引:3
预防和减轻油气储运系统地震火灾危险性是防震减灾中的重要课题。本文论述了油气储运系统的地震火灾特征及防火要求,对钢结构的防火涂料在遭到破坏和平时情况下的抗火性能进行了对比分析,并应用有限元法对油气储运系统中典型钢结构设备在地震火灾荷载作用下的抗火性能进行了数值模拟。研究结果表明,防火涂料遭到强地震荷载破坏后,钢结构的抗火性能大大降低。 相似文献
128.
129.
Investigation of waste disposal areas using electrical methods: a case study from Chania,Crete, Greece 总被引:1,自引:0,他引:1
Pantelis Soupios Ilias Papadopoulos Maria Kouli Irene Georgaki Filippos Vallianatos Eleni Kokkinou 《Environmental Geology》2007,51(7):1249-1261
A geophysical investigation of a landfill area was conducted as inextricable phase of a preliminary geotechnical, geological
and hydrogeological study of the area under investigation. Electrical resistivity tomography (ERT), one of the most promising
prospecting techniques mainly concerning its effective contribution to resolve several environmental problems, was applied
for the geophysical modeling. ERT is a robust imaging method the theory and implementation of which are well documented in
geophysical research literature. The survey site is located in Akrotirion Peninsula, about 7 km east of Chania city in Crete
I. The geological setting comprises Trypalion limestones, marly limestones and a clayed weathered layer. Cavities are also
identified at various scales which are recent tectono-karstic voids. Due to the above-mentioned geological singularity and
in the light of the requirement for an environmentally safe construction of the landfill, an ERT survey was carried out. Specifically,
seven geoelectrical tomographies were conducted reaching the prospecting depth of 36 m. The resulted images conduced, to overcome
geotechnical problems since the spatial distribution of karstic voids was determined, to plan the future sites for waste disposal
as the geological conditions were studied in detail and to reliably estimate the thickness of the already deposited wastes.
The resulted images were confirmed using available borehole logs and ambient noise measurements. 相似文献
130.
Anomaly analysis is used for various geophysics applications such as determination of geophysical structure's location and
border detections. Besides the classical geophysical techniques, artificial intelligence based image processing algorithms
have been found attractive for geophysical anomaly analysis. Recently, cellular neural networks (CNN) have been applied to
geophysical data and satisfactory results are reported. CNN provides fast and parallel computational capability for geophysical
image processing applications due to its filtering structure. The behavior of CNN is defined by two template matrices that
are adjusted by a properly supervised learning algorithm. After training stage for geophysical data, Bouguer anomaly maps
can be processed and analyzed sequentially. In this paper, CNN learning and processing capability have been improved, combining
Wavelet functions and backpropagation learning algorithms. The new architecture is denoted as Wavelet-Cellular Neural networks
(Wave-CNN) and it is employed to analyze Bouguer anomaly maps which are important to extract useful information in geophysics.
At first, Wave-CNN performance is tested on synthetic geophysical data, which are created by a computer environment. Then,
Bouguer anomaly maps of the Dumluca iron ore field have been analyzed and results are reported in comparison to real drilling
results. 相似文献