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601.
Ocean Science Journal - Clove oil (CO) is an effective anesthetic. Many hatcheries and research studies use clove oil to immobilize fish for artificial reproduction and surgery to suppress their... 相似文献
602.
Eko Setyobudi Chan-Hyeok Jeon Kwangho Choi Sung Il Lee Chung Il Lee Jeong-Ho Kim 《Ocean Science Journal》2013,48(2):197-205
The occurrence of Genus Anisakis nematode larvae in marine fishes and cephalopods is epidemiologically important because Anisakis simplex larval stage can cause a clinical disease in humans when infected hosts are consumed raw. Common squid (Todarodes pacificus) from Korean waters were investigated for anisakid nematodes infection during 2009~2011. In total, 1,556 larvae were collected from 615 common squids and 732 of them were subsequently identified by PCR-RFLP analysis of ITS rDNA. Depending on the sampling locations, the nematode larvae from common squid showed different prevalence, intensity and species distribution. A high prevalence (P) and mean intensity (MI) of infection were observed in the Yellow Sea (n = 250, P = 86.0%, MI = 5.99 larvae/host) and the southern sea of Korea (n = 126, P = 57.1%, MI = 3.36 larvae/host). Anisakis pegreffii was dominantly found in common squid from the southern sea (127/ 140, 90.7%) and the Yellow Sea (561/565, 98.9%). In contrast, the P and MI of infection were relatively low in the East Sea (n = 239, P = 8.37%, MI = 1.25 larvae/host). A. pegreffii was not found from the East Sea and 52.0% (13/25) of the nematodes were identified as A. simplex. Most of them were found in the body cavity or digestive tract of common squid, which are rarely consumed raw by humans. Considering the differenences in anisakid nematode species distribution and their microhabitat in common squid, it remains unclear whether common squid plays an important role in the epidemiology of human anisakis infection in Korea. Further extensive identification of anisakid nematodes in common squid, with geographical and seasonal information will be necessary. 相似文献
603.
Finite element simulation of fluid flow in fractured rock media 总被引:4,自引:3,他引:1
Fluid dynamics models are used by the petroleum industry to model single- and/or multi-phase flow within fractured rock formations,
in order to facilitate extraction of fluids such as oil and natural gas, and in other areas of engineering to study groundwater
flow, as well as to estimate contaminant seepage and transport. In this paper, the numerical modelling software Comsol is used to simulate air and water flow through a specimen of granite with a single vertical fracture subjected to triaxial
loading conditions. The intent of the model is to simulate triaxial test findings on a rock specimen with a natural fracture.
Fluid flow is simulated at various confining and inlet pressures using the cubic law. Model results were in good agreement
with laboratory findings. Pressure distribution along the fracture and across the specimen are as expected with a near linear
pressure distribution along the length of the fracture. A drawdown effect on pressure distribution across the specimen in
the vicinity of the fracture is also observed. Pressure gradient was largely uniform; however, some localised zones of high
gradient along the fracture are observed. 相似文献
604.
The serpentinite deposits derived from ultramafic rockswithin the South Korea mainly occur in the west ofChungcheongnam - Do,the south of South Korea,Ulsan andAndong area,and in the middle of South Korea,Gapyeongarea. The present study is on the genesis and m ineral compo-sitions of the serpentinite deposits consisting of abouteighteenmasses in the west of Chungcheongnam- Do. The ultramaficrocks mainly occur as discontinuously isolated lenticular or el-liptical bodies and extend to NNE d… 相似文献
605.
A new study investigates an unburied offshore “snaked” pipeline behavior under various types of seismic faults. The snaking of the pipeline is caused by the thermal/pressure expansion and soil friction. The snaking takes place at a certain distance from the pipeline's unrestrained end and gradually increases towards the restraint. It is shown that longitudinal seismic faults have less effect on a straight pipeline than a snaked pipeline. The new seismic analysis demonstrates that an increase of ground displacement causes a very small change in bending and longitudinal stresses. The new approach results in a safe, subsea pipeline construction and operation with a significant cost reduction. 相似文献
606.
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608.
This paper derives analytically the condition for the onset of diffuse mode bifurcations in thick-walled hollow cylinders with internal radius a, external radius b and length L under axial compression and confining pressure. The thick-walled cylindrical specimens are made of geomaterial characterized by Rudnicki's constitutive model, and the method of solution for the governing equations is the velocity potential approach employed by Chau. Numerical results show that thick-walled cylinders are stronger than thin-walled cylinders against diffuse mode bifurcations, including both buckling, axisymmetric and non-axisymmetric deformations. In contrast to the conclusion for solid cylinders (Chau), no buckling solution is found for γ = mπa / L smaller than about 0·7 under compression for a fixed and finite value of a / b (i.e. no buckling for long and slender hollow cylinders with small a / L and fixed b / a). When 0·7 < γ < 0·9, buckling is the expected first bifurcation; whereas, when γ > 0·9, bulging or barrelling is anticipated. The exact value of γ that excludes buckling and separates the buckling and barrelling phenomena depends on the current values of the constitutive parameters of the solid. Hollow cylinders with higher degree of anisotropy, disobeying normality flow rule, and subjected to confining pressure are more conducive to bifurcations than cylinders made of materials with isotropy, obeying normality, and subjected to no confining pressure. In addition, diffuse mode bifurcations are found possible in the pre-peak regime of the stress–strain curve. © 1998 John Wiley & Sons, Ltd. 相似文献
609.
Jieun Seo Seon‐Gyu Choi Minho Koo Chang Whan Oh InChang Ryu Gilljae Lee 《Resource Geology》2020,70(3):215-232
The Shinyemi and Gagok deposits, located in the Taebaeksan Basin, South Korea, display Zn–Pb mineralization along a contact between Cretaceous granitoids and Cambrian–Ordovician carbonates of the Joseon Supergroup. The Shinyemi mine is one of the largest polymetallic skarn‐type magnetite deposits in South Korea and comprises Fe and Fe–Mo–Zn skarns, and Zn–Cu–Pb replacement deposits. Both deposits yield similar Cretaceous mineralization ages, and granitoids associated with the two deposits displaying similar mineral textures and compositions, are highly evolved, and were emplaced at a shallow depth. They are classified as calc‐alkaline, I‐type granites (magnetite series) and were formed in a volcanic arc. Compositional variation is less in the Shinyemi granites and aplites (e.g., SiO2 = 74.4–76.6 wt% and 74.4–75.1 wt%, respectively) than in the Gagok granites and aplites (e.g., SiO2 = 65.6–68.0 wt% and 74.9–76.5 wt%, respectively). Furthermore, SiO2 vs K/Rb and SiO2 vs Rb/Sr diagrams indicate that the Shinyemi granitoids are more evolved than the Gagok granitoids. Shinyemi granitoids had been already differentiated highly in deep depth and then intruded into shallow depth, so both granite and aplite show the highly evolved similar chemical compositions. Whereas, less differentiated Gagok granitoids were separated into two phases in the last stage at shallow depth, so granite and aplite show different compositions. The amounts of granites and aplite are similar in the Shinyemi deposit, whereas the aplite appears in an amount less than the granite in the Gagok deposit. For this reason, the Shinyemi granitoids caused not only Fe enrichment during formation of the dolomite‐hosted magnesian skarn but also was associated with Mo mineralization in the Shinyemi deposit. Zn mineralization of the Gagok deposit was mainly caused by granite rather than aplite. Our data suggest that the variation in mineralization displayed by the two deposits resulted from differences in the compositions of their associated igneous intrusions. 相似文献
610.
Sangheon Yi Chang-Gyun Han Keun-Chang Oh In Sun Seo Dongwook Kim Jaeyoung Lee Min Han Hanwoo Choi Jaesoo Lim Sujeong Park Chang-Pyo Jun Taesop Cho 《第四纪科学杂志》2022,37(1):100-113
We comprehensively analyzed sediments obtained from an archeological excavation. A trench sediment profile of Maedun Cave (MC), South Korea, was analyzed geoarchaeologically. Multi-proxy analyses (palynomorphs, grain size, magnetic susceptibility, animal bones and artifacts) reflected the vegetation, hydroclimate and lives of prehistoric people at Marine Isotope Stage (MIS) 3 (ca. 40–30k cal a bp ) in the early Late Paleolithic. The palynoflora consisted of pollen and non-pollen palynomorphs. Under the air-circulation system in the cave, anemophilous pollen flowed in during the day, whereas waterborne pollen and spores, and freshwater algae, were transported by flooding during the summer monsoon rainy season. Mixed conifer and deciduous broad-leaved forest with an understory of pteridophytes flourished around the north-east central Korean Peninsula during MIS 3. Freshwater algae and grass pollen records may reflect precipitation intensity. It is assumed that they had flowed in during flooding caused by high precipitation during the enhanced East Asian summer monsoon, corresponding to Dansgaard–Oeschger (D/O) events 5 and 8 of δ18O GISP2 and Hulu Cave. The prehistoric people hunted herbivorous animals in the area around MC and sheltered inside it seasonally. They also used the grains of oats growing near the dwelling as a source of food. 相似文献