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41.
海水水质评价的倍斜率隶属函数聚类法 总被引:5,自引:0,他引:5
建立了宽域式倍斜率聚类的海水水质评价模式,其函数的右侧斜度为左侧斜率的2倍,勿求权重,直接聚类,海水水质评价实例说明,本文模糊综合评判法和灰色聚类法和更为合理,实用。 相似文献
42.
G.M. Kolesov 《环境科学学报(英文版)》1995,7(1):92-100
NeutronactivationmethodintheanalysisofenvironmentalobjectsG.M.Kolesov(V.I.VernadskyInstituteofGeochem。&Anal.Chem.,RussianAcad... 相似文献
43.
Soil and water loss in the Lancang River-Mekong River watershed (in Yunnan section, China) and its control measures 总被引:1,自引:0,他引:1
MekongRiverisoriginatedinthenorthernrangeofTibetQinghaiPlateauofChina,flowingthroughsixcountries,theyareChina(YunnanProvince),M?.. 相似文献
44.
Boris N. Porfiriev 《Environmental management》1996,20(1):25-33
An analysis is presented of the environmental effects of the most serious radiation accident recorded after Chernobyl, which
occurred in the formerly secret town of Tomsk-7 in Siberia, Russia, on 6, April 1993. Fortunately, it appears not to have
become a major industrial crisis or disaster. The causes of the accident are described. It is argued that a mixture of both
objective and subjective prerequisites, including specific human, organizational, and technological factors, were responsible
for the explosion or directly facilitated it. The Tomsk-7 accident's ecological, medical, social, and psychological consequences
are discussed. 相似文献
45.
Atsuyoshi Nakayama Norioki Kawasaki Ioannis Arvanitoyannis Seiichi Aiba Noboru Yamamoto 《Journal of Polymers and the Environment》1996,4(3):205-211
Biodegradable polyesters were synthesized by ring-opening copolymerization of -butyrolactone (BL) and its derivatives withl-lactide (LLA). Although tetraphenyl tin was the main catalyst used, other organometallic catalysts were used as well.1H and13C NMR spectra showed that poly(BL-co-LLA)s were statistical and that their number-average molecular weights were as high as 7×104. The maximum BL content obtained from copolymerization BL/LLA was around 17%. TheT
m andT
g values of the copolymers showed a gradual depression with an increase in BL content. NoT
m was obtained for the copolymers containing more than 13 mol% BL. The biodegradability of the copolyesters was evaluated by enzymatic hydrolysis and nonenzymatic hydrolysis tests. The enzymatic hydrolysis was carried out at 37°C for 24 h using lipases fromRhizopus arrhizus andR. delemar. Hydrolyses by both lipases showed that an increase in BL content of the copolymer resulted in enhanced biodegradability. Nonenzymatic accelerated hydrolysis of copolymers at 70°C was found to increase proportionally to their exposure time. The hydrolysis rate of these copolymers was considerably faster than that of PLLA. The higher hydrolyzability was recorded for the BL-rich copolymers. The copolymerization of -methyl--butyrolactone (MBL) or -ethyl--butyrolactone (EBL) with LLA resulted in relatively LA-rich copolymers. 相似文献
46.
/ The valleys of European piedmonts constitute changing narrow corridors within which water, matter, nutrients, energy, and species flow. The dispersion patterns of these flows have been significantly disturbed since the end of the 18th century. Thus, western European valleys have been changed into complex mosaics by implementation of socioeconomical programs. In order to define future actions allowing the preservation of this "ecocomplex" (Blandin and Lamotte 1988), it is necessary to gather precise information of the landscape dynamics. Hence, the study of the European river valleys must be based upon two major steps: (1)the analysis of the present landscape with suitable remote sensing techniques, allowing us to map the complex mosaic of narrow corridors; and (2) the analysis of temporal landscape development patterns since the first engineering works that have transformed the braided channel system. In this paper, the efficiency of the addition of two techniques is highlighted: (1) the "wavelet merging method" from multispectral and panchromatic SPOT images for the floodplain land-cover mapping, and (2) the historical reconstruction techniques from old maps and archive documents in order to analyze the cumulative impacts of engineering works on landscape diversity. To illustrate the method, a particularly complex case study is chosen: the Arc/Isere confluence (downstream from Albertville, Savoie, France). Remote sensing, field survey, and historical reconstruction allowed us to distinguish two types of spatial units: (1) the "functional sets" characterized by independent state factors (edaphic, hydrological, and topographic) and supporting a limited number of vegetation types (spontaneous or cultivated), and (2) the functional unit (= ecotope), which corresponds to a unique combination of vegetation type/functional set.KEY WORDS: Landscape ecology; Floodplains; Vegetation; Land use; Remote sensing; Historical reconstruction; Mapping; Merging methods; Human impacts; Alps; Isere river; France 相似文献
47.
Taylor AJ 《Disasters》1983,7(1):37-40
This paper defines the various levels within government, the voluntary agencies and the community which might benefit from training and makes suggestions as to where the emphasis should be placed. It points out that training programmes should be designed to meet the expressed needs of a particular group of trainees as well as be related to the current or potential disaster situation. 相似文献
48.
Carter W 《Disasters》1983,7(1):34-36
This paper discusses both the need for training within a wider context of community disaster preparedness and the major alternatives in methods of training. Emphasis is placed on the importance of compatibility between the resources within a given country and appropriate training programmes. 相似文献
49.
FUENSANTA CARAVACA DINO FIGUEROA ANTONIO ROLDÁn CONCEPCIÓN AZCÓN-AGUILAR 《Environmental management》2003,31(3):0412-0420
The reestablisment of autochthonous plant species is an essential strategy for recovering degraded areas under semiarid conditions.
A field experiment was carried out to assess the short-term effect of two reafforestation methods involving mycorrhizal inoculation
and compost addition on soil quality parameters and Rhamnus lycioides seedling growth. The nutrient content (NPK) and enzymatic activities (dehydrogenase, urease, protease-BAA, acid phosphatase
and β-glucosidase) increased and bulk density decreased in the rhizosphere soil with the organic amendment. Biomass C of rhizosphere
soil increased by at least 240% with respect to the control soil after mycorrhizal inoculation and the combination of compost
addition + mycorrhizal inoculation. Both mycorrhizal inoculation and composted organic residue addition increased R. lycioides seedling growth in the same proportion. In the short term, we conclude that the application of both reafforestation methods
not only enhances the establishment of R. lycioides seedlings, but also improves soil quality. 相似文献
50.
ERIC N. POWELL JOHN M. KLINCK EILEEN E. HOFMANN MARGARET A. McMANUS 《Environmental management》2003,31(1):0100-0121
A hydrodynamic–oyster population model was developed to assess the effect of changes in freshwater inflow on oyster populations
in Galveston Bay, Texas, USA. The population model includes the effects of environmental conditions, predators, and the oyster
parasite, Perkinsus marinus, on oyster populations. The hydrodynamic model includes the effects of wind stress, river runoff, tides, and oceanic exchange
on the circulation of the bay. Simulations were run for low, mean, and high freshwater inflow conditions under the present
(1993) hydrology and predicted hydrologies for 2024 and 2049 that include both changes in total freshwater inflow and diversions
of freshwater from one primary drainage basin to another.
Freshwater diversion to supply the Houston metropolitan area is predicted to negatively impact oyster production in Galveston
Bay. Fecundity and larval survivorship both decline. Mortality from Perkinsus marinus increases, but to a lesser extent. A larger negative impact in 2049 relative to 2024 originates from the larger drop in fecundity
under that hydrology. Changes in recruitment and mortality, resulting in lowered oyster abundance, occur because the bay volume
available for mixing freshwater input from the San Jacinto and Buffalo Bayou drainage basins that drain metropolitan Houston
is small in comparison to the volume of Trinity Bay that presently receives the bulk of the bay's freshwater inflow. A smaller
volume for mixing results in salinities that decline more rapidly and to a greater extent under conditions of high freshwater
discharge.
Thus, the decline in oyster abundance results from a disequilibrium between geography and salinity brought about by freshwater
diversion. Although the bay hydrology shifts, available hard substrate does not. The simulations stress the fact that it is
not just the well-appreciated reduction in freshwater inflow that can result in decreased oyster production. Changing the
location of freshwater inflow can also significantly impact the bay environment, even if the total amount of freshwater inflow
does not change. 相似文献