7th Annual Report on the International Status of Engineering Geology—Year 2001: Encompassing hydrogeology, environmental geology and the applied geosciences     

Allen W Hatheway  Yuji Kanaori 《Engineering Geology》2002,65(1):47-79

The year was marked by noteworthy advances in multinational consortia of commercial firms and of forward-looking universities. Again, the tenor of the practice of Engineering Geology has picked up. Not to be in the vanguard does indeed mean that one languishes in the dust raised by those on the move. Engineering geologists must understand an infinity of challenges stemming from land development, environmental protection and cleanup and resource development. This is a profession in which age can bring wisdom and increased competence.Most practitioners were busy in 2001; more than 80% of ASFE member companies report that business has increased or stayed the same for the past 6 months. Sixty percent of practitioners expect that their 2002 revenues will be stable or increase for Year 2002.  相似文献   

Isotope systematics of Li, Sr, Nd, and volatiles in Indian Ocean MORBs of the Rodrigues Triple Junction: Constraints on the origin of the DUPAL anomaly     

Yoshiro Nishio  Shun’ichi Nakai  Yuji Sano 《Geochimica et cosmochimica acta》2007,71(3):745-759

The DUPAL anomaly, a radiogenic isotope anomaly discovered in the Indian Ocean mantle, has been interpreted as due to a large-scale mantle heterogeneity. To provide new constraints on the DUPAL origin, we analyzed isotope ratios of Li, Sr, and Nd in fresh N-MORB glasses recovered from the Rodrigues Triple Junction in the Indian Ocean, and from the North Atlantic. The Li isotopic compositions of the Indian Ocean DUPAL N-MORBs were comparable to those of the North Atlantic non-DUPAL N-MORBs. The source of the DUPAL signature in Indian Ocean MORBs and the E-MORB-type enriched mantle source have quite different Li isotopic compositions. The ¹⁴³Nd/¹⁴⁴Nd values of both sources are significantly lower than those of the North Atlantic N-MORBs. The δ⁷Li values of most oceanic island basalts with similar low ¹⁴³Nd/¹⁴⁴Nd signatures are also higher than those of the North Atlantic N-MORBs, except for several Koolau lavas. The Li isotope results support the recent proposal that significant amounts of recycled lower continental crust might produce the radiogenic isotope signatures of the Indian Ocean DUPAL source.  相似文献   

Uranyl adsorption and surface speciation at the imogolite-water interface: Self-consistent spectroscopic and surface complexation models   总被引：1，自引：0，他引：1  

Yuji Arai  M. McBeath  J. Joye 《Geochimica et cosmochimica acta》2006,70(10):2492-2509

Macro- and molecular-scale knowledge of uranyl (U(VI)) partitioning reactions with soil/sediment mineral components is important in predicting U(VI) transport processes in the vadose zone and aquifers. In this study, U(VI) reactivity and surface speciation on a poorly crystalline aluminosilicate mineral, synthetic imogolite, were investigated using batch adsorption experiments, X-ray absorption spectroscopy (XAS), and surface complexation modeling. U(VI) uptake on imogolite surfaces was greatest at pH ∼7-8 (I = 0.1 M NaNO₃ solution, suspension density = 0.4 g/L [U(VI)]_i = 0.01-30 μM, equilibration with air). Uranyl uptake decreased with increasing sodium nitrate concentration in the range from 0.02 to 0.5 M. XAS analyses show that two U(VI) inner-sphere (bidentate mononuclear coordination on outer-wall aluminol groups) and one outer-sphere surface species are present on the imogolite surface, and the distribution of the surface species is pH dependent. At pH 8.8, bis-carbonato inner-sphere and tris-carbonato outer-sphere surface species are present. At pH 7, bis- and non-carbonato inner-sphere surface species co-exist, and the fraction of bis-carbonato species increases slightly with increasing I (0.1-0.5 M). At pH 5.3, U(VI) non-carbonato bidentate mononuclear surface species predominate (69%). A triple layer surface complexation model was developed with surface species that are consistent with the XAS analyses and macroscopic adsorption data. The proton stoichiometry of surface reactions was determined from both the pH dependence of U(VI) adsorption data in pH regions of surface species predominance and from bond-valence calculations. The bis-carbonato species required a distribution of surface charge between the surface and β charge planes in order to be consistent with both the spectroscopic and macroscopic adsorption data. This research indicates that U(VI)-carbonato ternary species on poorly crystalline aluminosilicate mineral surfaces may be important in controlling U(VI) mobility in low-temperature geochemical environments over a wide pH range (∼5-9), even at the partial pressure of carbon dioxide of ambient air (p_CO2 = 10^−3.45 atm).  相似文献   

Biological production in meso-scale eddies caused by frontal disturbances of the Kuroshio Extension   总被引：1，自引：0，他引：1  

Kimura  Shingo; Nakata  Hideaki; Okazaki  Yuji 《ICES Journal of Marine Science》2000,57(1):133-142

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渔港防台风等级评估研究 ——以霞关一级渔港为例          下载免费PDF全文

韩小燕  梁连松  董宇佳  姚辰阳 《海洋开发与管理》2020,37(5):57-62

文章通过对历史上影响苍南近岸海域的24场风暴潮过程进行分析筛选，确定1323“菲特”为最危险台风路径基础，设计了8~17级的间距为22.5 km的18条构造台风路径，采用FVCOM浪、潮、流耦合模式分别计算潮位场、流场和浪场分布，通过分析渔港岸线是否淹没、锚泊地是否船只走锚、防波堤防浪能力3个指标确定单项防台评估能力，按“就低不就高”的原则最终确定霞关一级渔港的防台风等级为9级，并且渔船锚泊是渔港的薄弱环节，最后结合研究过程中发现的问题，提出渔港防台风建议。  相似文献   

Impacts of regional warming on long‐term hypolimnetic anoxia and dissolved oxygen concentration in a deep lake          下载免费PDF全文

Yuji Ito  Kazuro Momii 《水文研究》2015,29(9):2232-2242

Although few reports have described long‐term continuous anoxia in aquatic systems, Lake Ikeda in Japan experienced such conditions in the hypolimnion from 1990 to 2010. The present study aimed to assess temporal fluctuations in the lake's thermal stability from 1978 to 2011 to understand the influence of regional climate change on hypolimnetic anoxia in this lake. Because complete vertical mixing, which supplies dissolved oxygen (DO) to the hypolimnion, potentially occurs on February, we calculated the Schmidt stability index (S) in February and compared it with hypolimnetic DO dynamics. Vertical water temperature profiles were calculated using a one‐dimensional model, and calculated temperatures and meteorological data were used to analyse annual fluctuations in water temperatures, thermocline depth, meteorological variables and S. We estimated that mean annual air and volume‐weighted water temperatures increased by 0.028 and 0.033 °C year^?1, respectively, from 1978 to 2011. Between 1986 and 1990, S and water temperature increased abruptly, probably due to a large upwards trend in air temperature (+0.239 °C year^?1). We hypothesize that a mixing regime that lacked overturn took effect at this time and that this regime lasted until 2011, when S was particularly small. These results demonstrate that abrupt climate warming in the late 1980s likely triggered the termination of complete mixing and caused the 21‐year period of successive anoxia in Lake Ikeda. We conclude that the lake response to a rapid shift in regional climate conditions was a key factor in changing the hypolimnetic water environment and that thermal stability in winter is a critical environmental factor controlling the mixing regime and anoxic conditions in deep lakes. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

A practical model to estimate photosynthetically active radiation using general meteorological elements in a temperate humid area and comparison among models     

Yasuko Mizoguchi  Yukio Yasuda  Yoshikazu Ohtani  Tsutomu Watanabe  Yuji Kominami  Katsumi Yamanoi 《Theoretical and Applied Climatology》2014,115(3-4):583-589

Although accurately evaluating photosynthetically active radiation is important, much effort is required to measure this radiation using a quantum sensor. We develop a new model that makes estimates using only general meteorological data—solar radiation, atmospheric pressure, air temperature, and relative humidity. Root mean square deviations for eight datasets at five sites in Japan were smaller than 5.2 %, similar to error in other studies and to individual differences of quantum sensors. Most root mean square deviations of nine previous models and our eight datasets are larger than that of the new estimation model, which performed well. This suggests that the model is useful for estimating photosynthetically active radiation in a temperate, humid area of Japan.  相似文献   

加密自动气象站雨量计资料的质量控制 及其相关关系的研究   总被引：3，自引：1，他引：2  

刘雨佳  陈洪滨  金德镇  齐彦斌  崔莲 《大气科学》2014,38(1):159-170

在长春—四平地区100 km×100 km的范围内,分布有平均间隔10 km左右的147个自动气象站。结合该区域雷达回波强度资料,对2007～2011年4～10月的气象站雨量计小时降水数据进行质量控制。多步骤质量控制结果显示,有141个自动站雨量计的数据通过了检查,删除了6个错误站点的数据,对有疑问时段的数据作了标记。 利用质量控制后的5年夏季半年自动站雨量计小时降水数据,进行相关关系统计分析表明：距离在10 km以内的雨量计测量,平均相关系数均能达到0.6以上;雨量计距离小于5 km,平均相关系数在0.7以上;而站点距离超过20 km,相关系数普遍降到0.4以下;随着统计时间的增长（从分钟到月降水量）,每个雨量计的测量值具有更高的空间代表性。  相似文献   

Characteristics of neighborhood interaction in urban land-use changes: A comparative study between three metropolitan areas of Japan     

ZHAO Yaolong  CUI Bingliang  MURAYAMA Yuji 《地理学报》2011,21(1):65-78

Local spatial interaction between neighborhood land-use categories (i.e. neighborhood interaction) is an important factor which affects urban land-use change patterns. Therefore, it is a key component in cellular automata (CA)-based urban geosimulation models towards the simulation and forecast of urban land-use changes. Purpose of this paper is to interpret the similarities and differences of the characteristics of neighborhood interaction in urban land-use changes of different metropolitan areas in Japan for providing empirical materials to understand the mechanism of urban land-use changes and construct urban geosimulation models. Characteristics of neighborhood interaction in urban land-use changes of three metropolitan areas in Japan, i.e. Tokyo, Osaka, and Nagoya, were compared using such aids as the neighborhood interaction model and similarity measure function. As a result, urban land-use in the three metropolitan areas was found to have had similar structure and patterns during the study period. Characteristics of neighborhood interaction in urban land-use changes are quite different from land-use categories, meaning that the mechanism of urban land-use changes comparatively differs among land-use categories. Characteristics of neighborhood interaction reveal the effect of spatial autocorrelation in the spatial process of urban land-use changes in the three metropolitan areas, which correspond with the characteristics of agglomeration of urban land-use allocation in Japan. Neighborhood interaction amidst urban land-use changes between the three metropolitan areas generally showed similar characteristics. The regressed neighborhood interaction coefficients in the models may represent the general characteristics of neighborhood effect on urban land-use changes in the cities of Japan. The results provide very significant materials for exploring the mechanism of urban land-use changes and the construction of universal urban geosimulation models which may be applied to any city in Japan.  相似文献   

2022年7-9月全球火山活动简报     

宋雨佳  盘晓东  康建红 《中国地震》2022,38(4):820-824

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