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591.
The generation mechanisms of convective gravity waves in the stratosphere are investigated in a three-dimensional framework by conducting numerical simulations of four ideal storms under different environmental conditions: one un-sheared and three constant low-level sheared basic-state winds with the depth of the shear layer of 6 km and the surface wind speeds (Us) of 8, 18, and 28 m s?1, using the Advanced Regional Prediction System (ARPS) model. The storms simulated under the un-sheared (Us = 0 m s?1), weakly sheared (Us = 8 and 18ms?1), and strongly sheared (Us = 28ms?1) basicstate winds are classified into single-cell, multicell, and supercell storms, respectively. For each storm, the wave perturbations in a control simulation, including nonlinearity and microphysical processes, are compared with those in quasi-linear dry simulations forced by diabatic forcing and nonlinear forcing that are obtained from the control simulation. The gravity waves generated by the two forcing terms in the quasi-linear dry simulations are out of phase with each other for all of the storms. The gravity waves in the control simulation are represented by a linear sum of the wave perturbations generated by the nonlinear forcing and diabatic forcing. This result is consistent with the results of previous studies in a two-dimensional framework. This implies that both forcing mechanisms are important for generating the convective gravity waves in the three-dimensional framework as well. The characteristics of the three-dimensional gravity waves in the stratosphere were determined by the spectral combination of the forcing terms and the wave-filtering and resonance factor that is determined from the basic-state wind and stability as well as the vertical structure of the forcing. 相似文献
592.
To understand the effects of temperature, pH and mechanical stress on the pressure dissolution of quartz, two experiments using monocrystalline quartz samples were conducted. The first was a closed-fluid experiment to investigate the effect of pH, and the second was a flow-through experiment to investigate stress and temperature effects. To initiate the pressure dissolution, a pair of samples was immersed in a solution with a prescribed pH. The samples were stressed mechanically by pressing one sample against the other. In the closed-fluid experiments, the pH of the solution was fixed to 7, 9, 11 and 13, the applied stress was approximately 200 MPa and temperature 25°C. The flow-through experiments were conducted at three different temperatures (35, 50 and 75°C) at the same pH 11.7. The value of the applied stress was 7.32, 13.72, 21.42 or 25.27 MPa. During each of these dissolution tests, the solution was regularly sampled and analyzed by an Inductively Coupled Plasma-Atomic Emission Spectrometry technique to measure Si-concentration. With the measured Si-concentration, a dissolution rate constant was computed the different pH, stress and temperature conditions. The rate constant is proportional to pH, stress and temperature, as indicated in the literature. It should be noted that the rate constant for the highest stress (200 MPa) was considerably greater than for the other cases. In addition, island-channel patterns characterized by micro-cracks a few nanometers in length were seen on the dissolved parts of the samples. The findings and the measured data in this paper may be useful for the future development of theoretical models for pressure dissolution and its validation. 相似文献
593.
594.
Hyunwook Choo Jaewook Hwang Youngmin Choi Changho Lee 《Marine Georesources & Geotechnology》2016,34(6):571-580
One of the distinguishing features of volcanic beach sand compared to typical silica sand can be found in its relatively high iron content; however, studies on the effect of iron content on the engineering properties of volcanic beach sand have been very limited until now. Consequently, this experimental investigation quantifies the effect of iron content on the engineering properties of Ulleung volcanic beach sands, including small strain stiffness, compressibility, friction angle, and cone tip resistance. Various geotechnical experiments were performed, and test results demonstrate that the small strain stiffness increases with an increase in iron content because of the increased interparticle contact stiffness. In addition, the elastic deformation of soil particles decreases with an increase in iron content because of the greater elastic modulus of iron compared to that of silica. In contrast, the effects of iron content on the intermediate strain constrained modulus and on the large strain friction angle are insignificant, and these properties are mainly determined by state variables. The relationship between the stress-normalized cone tip resistance and the state parameter of tested Ulleung sand is very similar to that on silica sands, reflecting that the effect of iron contents on the cone tip resistance is minimal. 相似文献
595.
Rock mass rating (RMR) values along additional drifts that are to be constructed during mine site redevelopment (Gagok mine, Korea) were estimated using multiple criteria indicator Kriging with borehole RMR and electrical resistivity tomography data. This study outlines two potential correction methods that supplement indicator Kriging and that can reduce error, allowing more accurate estimation of RMR values. The correction methods used a filtering of indirect data affected by drifts (FIED) method to reduce uncertainties and errors within electrical resistivity tomography data caused by changes in setup and the location of existing drifts. In addition, a correction indicating accurate representation of indirect data (CARI) method was used to resolve distortions in drilling log results. This meant that 73 % of the estimated RMR values were assigned to the correct RMR class, with only 1 % of these values being overestimated. The sensitivity of the FIED method was 4 %, with the linear CARI method having a sensitivity of 56–60 % and the logarithmic CARI method having a sensitivity of 61–65 %. 相似文献
596.
Subramaniam Thatchaneshkanth Lee Hee-Jung Jeung Hee-Do Kang Hyun-Sil Kim Chul-Won Kim Hyung-Seop Cho Young-Ghan Choi Kwang-Sik 《Ocean Science Journal》2021,56(4):424-433
Ocean Science Journal - The Gray mussel Crenomytilus grayanus occurs in high density in the shallow rocky subtidal zone on the east coast of Korea, where the mussel dominates the shallow subtidal... 相似文献
597.
Kim Young Ok Choi Jungmin Kang Hyung-Ku Noh Jae Hoon Choi Dong Han Oh Kyung-Hee 《Ocean Science Journal》2021,56(1):69-77
Ocean Science Journal - As planktonic ciliates have been recognized as important players in marine microbial food webs, relevant studies have been conducted in the western coastal waters of the... 相似文献
598.
Kwon Yong Min Bae Seung Sub Choi Grace Lim Ji Yeon Jung Yoon-Hee Chung Dawoon 《Ocean Science Journal》2021,56(1):1-17
Ocean Science Journal - Studies on marine fungi (termed as ‘marine-derived fungi’ in this paper) have been significantly increasing worldwide because of the critical role displayed by... 相似文献
599.
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
600.
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