The variability of internal tides in the Northern South China Sea     

Barry B. Ma  Ren-Chieh Lien  Dong S. Ko 《Journal of Oceanography》2013,69(5):619-630

An array of three bottom-mounted ADCP moorings was deployed on the prevailing propagation path of strong internal tides for nearly 1 year across the continental slope in the northern South China Sea. These velocity measurements are used to study the intra-annual variability of diurnal and semidiurnal internal tidal energy in the region. A numerical model, the Luzon Strait Ocean Nowcast/Forecast System developed at the U.S. Naval Research Laboratory that covers the northern South China Sea and the Kuroshio, is used to interpret the observed variation of internal tidal energy on the Dongsha slope. Internal tides are generated primarily at the two submarine ridges in the Luzon Strait. At the western ridge generation site, the westward energy flux of the diurnal internal tide is sensitive to the stratification and isopycnal slope associated with the Kuroshio. The horizontal shear at the Kuroshio front does not modify the propagation path of either diurnal or semidiurnal tides because the relative vorticity of the Kuroshio in Luzon Strait is not strong enough to increase the effective inertial frequency to the intrinsic frequency of the internal tides. The variation of internal tidal energy on the continental slope and Dongsha plateau can be attributed to the variation in tidal beam propagation in the northern South China Sea.  相似文献   

Platinum-group elements in ores from the Kalmakyr porphyry Cu–Au–Mo deposit, Uzbekistan: bulk geochemical and laser ablation ICP-MS data     

Jan Pašava  Anna Vymazalová  Jan Košler  Rustam I. Koneev  Alexander V. Jukov  Rustam A. Khalmatov 《Mineralium Deposita》2010,45(5):411-418

We studied primary ore samples from Kalmakyr, a giant Cu–Au–Mo porphyry deposit in eastern Uzbekistan. Disseminated and stockwork-type high-grade Cu–Au–Mo mineralization showed average concentrations of 55 ppb Pd, 5.5 ppb Pt, 0.95 ppb Rh, 0.49 ppb Ir, and 4.1 ppm Au (n = 8). This type of mineralization is characterized by the presence of pyrite, chalcopyrite, molybdenite, and gold. A peak Pd content of 292 ppb was determined in a base-metal-rich quartz vein in granodiorite porphyry, which contains galena, sphalerite, chalcopyrite, tetrahedrite, and gold. Palladium correlates with Cu, Ag, Se, and S. Mineralogical and laser ablation ICP-MS study confirmed that Pd is homogeneously distributed in chalcopyrite, which contains up to 110 ppm Pd, and tetrahedrite, containing up to 20 ppm Pd. An assessment of the Pd and Pt budget at Kalmakyr showed the potential of approximately 17 t of Pd and 1.7 t of Pt.  相似文献   

Comparison of microbial communities in petroleum-contaminated groundwater using genetic and metabolic profiles at Kyonggi-Do,South Korea     

Eun-Hee Lee  Jaisoo Kim  Ji-Young Kim  So-Yeon Koo  Sang-Dong Lee  Kyung-Seok Ko  Dong-Chan Ko  Byoung-Woo Yum  Kyung-Suk Cho 《Environmental Earth Sciences》2010,60(2):371-382

This research has been performed to determine the differences in microbial communities according to physicochemical properties such as concentrations of volatile aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene (BTEX), dissolved oxygen (DO), electron acceptors, etc., in oil-contaminated groundwaters at Kyonggi-Do, South Korea. The properties of bacterial and microbial communities were analyzed by 16S polymerase chain reaction (PCR) denaturing gradient gel electrophoresis (DGGE) fingerprinting method and community-level physiological profiling (CLPP) using Eco-plate, respectively. Based on the DGGE fingerprints, the similarities of bacterial community structures were high with similar DO levels, and low with different DO levels. Whereas the dominant bacterial groups in GW13 (highest BTEX and lowest DO) were acidobacteria, α-proteobacteria, β-proteobacteria, γ-proteobacteria, δ-proteobacteria, and spirochetes, those in GW7 (highest BTEX and highest DO) were actinobacteria, α-proteobacteria, β-proteobacteria, γ-proteobacteria, δ-proteobacteria, and sphingobacteria. Based on the CLPP results, the groundwater samples were roughly divided into three groups: above 4 mg/L in DO (group 1: GW3 and GW7), below 4 mg/L in DO (group 2: GW8, W1, W2, W3, and BH10), and highly contaminated with BTEX (group 3: GW13). Shannon index showed that the microbial diversities and equitabilities were higher in shallower aquifer samples. Overall, this study verified that the greatest influencing factors on microbial/bacterial communities in groundwaters were DO and carbon sources, although BTEX concentration was one of the major factors.  相似文献   

Experimental developments for studying static and seismic behavior of retaining walls with liquefiable backfills     

M. M. Dewoolkar  H. -Y. Ko  R. Y. S. Pak 《Soil Dynamics and Earthquake Engineering》2000,19(8):75-593

The effects of earthquakes on cantilever retaining walls with liquefiable backfills were studied. The experimental techniques utilized in this study are discussed here. A series of centrifuge tests was conducted on aluminum, fixed-base, cantilever wall models retaining saturated, cohesionless backfills. Accelerations on the walls and in the backfill, static and excess pore pressures in the soil, and deflections and bending strains in the wall were measured. In addition, direct measurements of static and dynamic lateral earth pressures were made. In some tests, sand backfills were saturated with the substitute pore fluid metolose. Modeling of model type experiments were conducted. The experimental measurements were found internally consistent and repeatable. Both static and dynamic earth pressure measurements were determined to be reliable. It was also observed that for the test configuration adopted, a special boundary treatment such as the use of duxseal is optional. Static and seismic modeling of models were also successful, which indicated that the assumed scaling relations were essentially correct.  相似文献   

Temporal dynamics,meteorological effects,secondary organic aerosol estimation,and source identification of size-segregated carbonaceous aerosols     

Burçak Tarhan  Ebru Koçak 《洁净——土壤、空气、水》2024,52(4):2300095

During the period 2019–2020, size-segregated aerosol samples containing elemental and organic carbon (EC and OC) were investigated. These samples were collected weekly using an eight-stage cascade impactor from an urban site located at Aksaray University, Aksaray. The quantification of EC and OC was carried out through a thermal-optical transmission device. The results revealed consistent size distribution attributes of EC and OC between winter and summer. Although EC accounted for an insignificant percentage (4.4%) of particulate matter (PM) in the PM_9.0–10.0 fraction during winter, a more substantial portion of OC in the same fraction (13.4%) comprised EC. Seasonal variations were distinct for EC but not significant for OC. Strong correlations between OC and EC were observed in coarse particle fractions, indicating a common source, with weaker correlations in fine particles. The highest OC/EC ratio was in the PM_0.43–0.65 fraction, followed by PM_2.1–3.3. The ratio of OC to EC in fine PM exceeded the threshold of 15 consistently. The observation indicates that as particle size increases, there is a noticeable decline in the OC to EC ratios. Secondary organic aerosols (SOA) accounted for 60.8% (winter) and 89.8% (summer) of OC values, emphasizing the substantial impact of SOA on Aksaray's atmosphere. Both seasons exhibited a multimodal distribution of ambient OC. In winter, the EC distribution was dominated by fine particles, with a bimodal pattern (PM_1.1–2.1 and PM_0.43–0.65 peaks). Common pollutant sources, including traffic emissions, road dust, biogenic emissions, and coal combustion, were identified for both seasons in coarse and fine particle fractions. These findings underscore the importance of emission control strategies targeting fine PM in Aksaray.  相似文献   

滇池微囊藻水华多糖的提取和化学特征   总被引：1，自引：0，他引：1  

耿兰芳  李朋富  宋立荣  孔繁翔  于洋  王玉炯  刘志礼 《湖泊科学》2007,19(6):637-642

为了研究"水华"微囊藻多糖及其对水体化学和生态特性的影响,以去离子水、pH5的缓冲液和pH9.2的缓冲液为提取液,分别在4℃和80℃条件下从滇池"水华"微囊藻中提取多糖,并对其所提多糖部分化学特征进行分析.结果表明pH9.2的缓冲液所提多糖总得率最高,为2.25%;pH5的磷酸盐缓冲液所提多糖总得率最低,为0.383%.溶解性分析表明,不同提取液所提多糖在所试验的几种溶剂中表现为不溶、分散或部分溶解,未能找到将多糖完全溶解的溶剂.气相色谱和气-质联用分析表明,不同提取液所提多糖都含有中性单糖鼠李糖、阿拉伯糖、甘露糖、葡萄糖、半乳糖和一个未知糖.硫酸-咔唑法分析显示不同提取液所提多糖含有糖醛酸.电感耦合等离子光谱显示去离子水4℃条件下所提多糖含有很高的金属元素钙和镁,分别为2.15%和0.4%.初步研究显示,"水华"微囊藻多糖为酸性杂多糖,低溶解性显示在自然水体中它易形成多糖颗粒,有较高含量的金属元素说明它会影响到这些金属元素在滇池中的溶解、沉积、生物利用和循环,特别是钙和镁.  相似文献   

Centrifuge modeling of disconnected piled raft using vertical pushover tests     

Park  Heon-Joon  Ko  Kil-Wan  Song  Young-Hun  Song  Myung-Jun  Jin  Seokwoo  Ha  Jeong-Gon  Kim  Dong-Soo 《Acta Geotechnica》2020,15(9):2637-2648

Acta Geotechnica - A disconnected piled raft (DPR) foundation has been introduced as an effective pile design to reduce the vertical loading experienced by the pile. The characterization of DPRs...  相似文献   

Assessment of Tidal Stream Energy Resources Using a Numerical Model in Southwestern Sea of Korea     

Park  Jun-Seok  Lee  Chol-Young  Park  Jin-Soon  Choi  Hyun-Woo  Ko  Dong-Hui  Lee  Jung-Lyul 《Ocean Science Journal》2019,54(4):529-541

Ocean Science Journal - In this study, tidal stream energy resources of the Southwestern Sea of Korea were assessed using a numerical model, Modelo Hidrodinâmico (MOHID). This numerical model...  相似文献   

Implementation of porous material through eco-tech for deep cement–soil mixing     

You-Seong Kim  Se-Gwan Seo  Hyoung-Woo Ko 《Marine Georesources & Geotechnology》2018,36(8):931-939

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A fifty-year production and economic assessment of common property-based management of marine living common resources: A case study for the women divers communities in Jeju,South Korea     

Jae-Young Ko  Glenn A. Jones  Moon-Soo Heo  Young-Su Kang  Sang-Hyuck Kang 《Marine Policy》2010

We examined the conditions of successful common property-based management for coastal marine living resources, using a case of historically and anthropologically well established women divers communities on Jeju Island, South Korea, focusing on their decentralized work rules and production records. Due to their tight social network and work rule, the women divers have harvested coastal marine living resources with limited fishing pressure exclusively from their village fishing grounds for over 400 years. However, their harvest patterns have been mostly reactive to market prices, eventually requiring direct governmental regulations such as total allowable catch in some cases. Most recently, the communities have been experiencing multiple challenges: their aging population, water pollution in the coastal zone, competition with cultured products and imported seafood, and expanding barren grounds. These challenges demand a multi-scale/dimensional response if the women divers communities are to keep their village fishing grounds and communities sustainable.  相似文献