隔震规则桥梁的组合阻尼比     

Hwang  JS 赵松岐 《世界地震工程》1997,13(3):80-88

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挪威特隆赫姆和叙利切尔马地区玄武岩容矿的块状...     

福克.  JS 姚士新 《国外矿床地质》1990,(3):65-73

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南非干燥台地风化粒玄岩稀土元素分馏和铈异常特征     

Marsh  JS 陈存俊 《国外地质与勘测》1993,(2):21-25

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Coral skeletal delta(15)N reveals isotopic traces of an agricultural revolution     

Marion GS  Dunbar RB  Mucciarone DA  Kremer JN  Lansing JS  Arthawiguna A 《Marine pollution bulletin》2005,50(9):931-944

This study introduces a new method of tracing the history of nutrient loading in coastal oceans via delta(15)N analysis of organic nitrogen preserved in the skeleton of the massive Porites coral. Four coral cores were collected in Bali, Indonesia, from reefs exposed to high levels of fertilizers in agricultural run-off, from lagoonal corals impacted by sewage, and from a reef located 30 km offshore. Skeletal delta(15)N in the agriculturally exposed coral declined from 10.7+/-0.4 per thousand in 1970-1971, when synthetic fertilizers (-0.8 per thousand+/-0.2 per thousand) were introduced to Bali, to a depleted "anthropogenic" baseline of 3.5 per thousand+/-0.4% in the mid-1990s. delta(15)N values were negatively correlated with rainfall, suggesting that marine delta(15)N lowers during flood-bourn influxes of waste fertilizers. Reef cores exposed to untreated sewage in terrestrial discharge were enriched (7.8 and 7.3+/-0.4 per thousand), while the offshore core reflected background oceanic signals (6.2+/-0.4 per thousand). delta(15)N, N concentration, and C:N systematics indicate that the N isotopic composition of skeletal organic matter was generally well preserved over 30 years. We suggest that skeletal organic delta(15)N can serve as a recorder of past nitrogen sources. In Bali, this tracer suggests that the intensification of Western style agricultural practices since 1970 are contributing to the degradation of coastal coral reefs.  相似文献   

A modification to the Bouwer and Rice method of slug-test analysis for large-diameter, hand-dug wells     

Rupp DE  Selker JS  Simůnek J 《Ground water》2001,39(2):308-314

The Bouwer and Rice method of estimating the saturated hydraulic conductivity (Ks) from slug-test data was evaluated for geometries typical of hand-dug wells. A two-dimensional, radially symmetric and variably saturated, ground water transport model was used to simulate well recovery given a range of well and aquifer geometries and unsaturated soil properties, the latter in terms of the van Genuchten parameters. The standard Bouwer and Rice method, when applied to the modeled recharge rates, underestimated Ks by factors ranging from 1.3 to 5.6, depending on the well geometry and the soil type. The Bouwer and Rice analytical solution was modified to better explain the recovery rates as predicted by the numerical model, which revealed a significant dependence on the unsaturated soil for the shallow and wide geometries that are typical of traditional wells. The modification introduces a new parameter to the Bouwer and Rice analysis that is a measure of soil capillarity which improves the accuracy of Ks estimates by tenfold for the geometries tested.  相似文献   

海冰的实时航空电磁测量     

Holl.  JS 孟庆敏 《物探化探译丛》1993,(A07):47-51

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Benthic changes during 10 years of organic enrichment by McMurdo Station, Antarctica     

Conlan KE  Kim SL  Lenihan HS  Oliver JS 《Marine pollution bulletin》2004,49(1-2):43-60

A benthic habitat along the coast of McMurdo Station in the Ross Sea, Antarctica is enriched by sewage from the station and altered by hydrocarbons and heavy metals in an adjacent historic dumpsite. We report on 10 years of change in the benthic communities from 1988 to 1998 and compare enrichment effects at Australia's Casey Station, East Antarctica. Despite being 14 km apart, reference communities upcurrent and downcurrent of McMurdo Station remained closely similar over time, dominated in all years by a tube building polychaete, Spiophanes tcherniae. The community bordering McMurdo Station was generally a third as abundant as communities at the reference sites over the decade of sampling, although diversity was as high or higher, except in the most contaminated areas. In 1992, organic enrichment of the outfall community intensified and within the year, the opportunistic polychaetes Aphelochaeta sp., Ophryotrocha notialis, Capitella perarmata, and Leitoscoloplos kerguelensis became dominant. Since 1996, two of the three enriched communities have increased in resemblance to the reference communities. Given the observed responsiveness of the benthos to the outfall so far, further changes are anticipated within the year following implementation of sewage treatment in 2003. Organic enrichment by McMurdo Station has had a greater impact on benthic community structure than at Australia's Casey Station.  相似文献   

近50年来大连气候变化趋势分析   总被引：17，自引：1，他引：17  

魏东岚  周薇 《气象》2005,31(8):71-73

利用滑动平均、滑动变异系数等方法对大连1951-2001年间的气温与降水量资料进行分析，发现大连气温具有明显的上升趋势，降水量有逐渐减少趋势；各季气温变化趋势有所差异，冬季升温最明显，但在近期升温幅度有所下降，而夏季气温近期升幅比较明显；整体气候呈现暖千化趋势。在此基础上，进一步分析了大连1949年以来严重冷、暖冬事件及多雨与少雨年出现的规律与特征。  相似文献   

热带海洋全球大气计划的海气耦合响应试验（COARE）     

Godf.  JS 林明智 《气象科技》1996,(2):30-33

热带海洋全球大气计划的海气耦合响应试验（ＣＯＡＲＥ）Ｊ．Ｓ．Ｇｏｄｆｒｅｙ（澳大利亚）１引言１９９２年１１月－１９９３年２月，在巴布亚新几内亚以东地区进行了热带海洋全球大气计划（ＴＯＧＭ）的海气耦合响应试验（ＣＯＡＲＥ），这是人们已进行的阵容最强的海...  相似文献   

Contamination of saltmarsh sediments and biota by CCA treated wood walkways   总被引：1，自引：0，他引：1  

Weis JS  Weis P 《Marine pollution bulletin》2002,44(6):504-510

Sediments, marsh grasses, and ribbed mussels were collected under two CCA wood walkways (15 and 3 years old) and 1, 3, and 10 m out, in the high, middle and low marshes. These sediments, and samples from reference sites, were analyzed for Cu, Cr, and As by atomic absorption spectrophotometry. Metal concentrations were highly elevated under the walkways and up to 10 m away. Dispersal of contaminants near the old walkway was greatest in the low marsh, less in the middle, and least in the high marsh, corresponding to periods of tidal inundation. Accumulation under the walkway was generally greatest in the low marsh. Contamination was much higher in sediments under the new walkway than the old one, but metals had not dispersed as far. Accumulation patterns in plants were similar, but the contamination did not disperse as far and was not greater under the new vs the old walkway, despite differences in sediment concentrations. In mussels, bioaccumulation was seldom statistically significant, due largely to small sample sizes.  相似文献