• 대한조선학회논문집
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• 제32권1호
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• pp.70-82
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• 1995

본 연구에서는 복잡한 해저지형을 고려한 조류의 거동을 예측하기 위한 3차원 다중기법을 개발하였다. 복잡한 해저지형을 보다 정확하고 효과적으로 고려하기 위하여 연직방향으로 $\sigma$좌표계를 도입하였다. 시간의 전개에 있어서는 계산상의 오차를 감소시키기 위하여 강한 감쇠효과를 가지는 것으로 알려진 Euler backward scheme을 Leapfrog scheme과 결합하여 사용하였다. 또한, 격자체계로는 해의 안정성을 위하여 교차격자체계를 사용하였다. 본 논문에서는, 계산예로서 다양한 해저지형을 가진 직육면체 유체영역을 설정하여 조류의 연직구조와 조류의 방향에 미치는 해저지형의 효과를 조사하였다. 본 연구에서 제안된, 해저지형을 직접적으로 고려한 3차원 다중기법의 계산결과와 2차원 수심평균기법에 의한 계산결과를 비교하여, 조류의 크기와 방향은 특히 복잡한 해저지형을 가지는 천수역에서 해저지형에 의하여 크게 영향을 받음을 알 수 있었다.

• 한국수소및신에너지학회논문집
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• 제17권1호
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• pp.62-68
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• 2006

High temperature electrolysis is a promising technology to produce massively hydrogen using renewable and nuclear energy. Solid oxide fuel cell materials are candidates as the components of steam electrolysers. However, the polarization characteristics of the typical electrode materials during the electrolysis have not been intensively investigated. In this study, NiO electrode was deposited on YSZ electrolyte by spin coat process and firing at $1300^{\circ}C$. Pt electrode was applied on the other side of the electrolyte to compare the polarization characteristics with those by NiO during electrolysis. The $H_2$ evolution rate was also monitored by measuring the electromotive force of Lambda probe and calculated by thermodynamic consideration. At low current density, Pt showed lower cathodic polarization and thus higher current efficiency than Ni, but the oxidation of Ni into NiO caused the increase of anodic resistance with increasing current density. High overpotential induced high power consumption to produce hydrogen by electrolysis.

• 한국물환경학회지
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• 제29권2호
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• pp.232-238
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• 2013

Water temperature is key factor influencing growth and reproduction of fish and its increase give rise to various physiological changes including gene expression. Heat shock protein (Hsp), one of the molecular chaperones, is highly conserved throughout evolution and its expression is induced by various stressors such as temperature, oxidative, physical and chemical stresses. Here, we isolated partial cDNA clones encoding 70-kDa Hsp (Hsp70) and $\beta$-actin using reverse transcriptase-PCR (RT-PCR) from gut of Rhynchocypris kumgangensis, a Korean indigenous species and cold-water fish, and investigated expression profiles of Hsp70 under an increase of water temperature using $\beta$-actin as an internal control for RT-PCR. Cloned Hsp70 cDNA of R. kumgangensis showed homology to Ctenopharyngodon idella (96%), Hypophthalmichthys molitrix (96%), Danio rerio (93%) and Oncorhynchus mykiss (81%) Hsp70. Cloned $\beta$-actin cDNA of R. kumgangensis showed homology to D. rerio (98%), H. molitrix (97%), C. idella (97%) and O. mykiss (90%) $\beta$-actin. Both mRNA of Hsp70 and $\beta$-actin were expressed in gut, brain, and liver in R. kumgangensis. Futhermore, expression of Hsp70, in brain, was highly augmented by an increase of water temperature. These results suggest that Hsp70 mRNA expression level in brain can be used as a biological molecular marker to represent physiological stress against an increase of water temperature.

• International Journal of Industrial Entomology and Biomaterials
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• 제6권2호
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• pp.171-178
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• 2003

Four thermo-tolerant lines of silkworm, Bombyx mori, (L.) viz., A HT, B HT (Chinese type) and F HT, G HT (Japanese type) were evolved by utilizing the breeding resource material (identified from initial screening at a temperature of 31 ${\pm} 1^{\circ}C$ and relative humidity 85 ${\pm}$ 5%) through conventional breeding. These tolerant lines were crossed with productive breeds and forty four hybrids were evaluated on eight economic traits by the Multiple Trait Evaluation Index Method. Ten hybrids were short-listed based on the average evaluation index value larger than 50 for eight economic traits studied. The identified ten hybrids recorded higher index values (＞ 50) for most of the traits studied. Single hybrid G ${\times}$ CSR12 indicated average index value larger than 50 for six traits viz., pupation number (58), cocoon weight (67), shell weight (65), average filament length (74), raw silk % (69), reelability % (51) except for shell ratio % (41). The standard deviation of the cocoons in the above hybrid was 8.41 in the hybrid cocoon length and width measurement. However, two selected hybrids viz., A ${\times}$ CSR5 and G ${\times}$ CSR13 recorded average index value larger than 50 for all the traits viz., pupation number (57, 60), cocoon weight (50, 54), shell weight (56, 57), shell ratio percentage (59, 53), average filament length (55, 60), raw silk percentage (63, 67) and reelability percentage (53, 53). The standard deviation of the cocoons in the two selected hybrids viz., A ${\times}$ CSR5 and G ${\times}$ CSR13 was 8.41 and 8.06 respectively in the cocoon length and width measurement.

• 천문학회지
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• 제52권6호
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• pp.235-244
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• 2019

We present the results of near-infrared imaging observations of the galaxy overdensity around the z = 1.44 radio-loud active galactic nucleus (AGN) 6CE1100+3505, which was carried out with the purpose of sampling the redshifted Hα emission from the actively star-forming galaxies that could constitute the overdensity. The existence of the structure around this AGN was spectroscopically confirmed by previous grism observations which are however limited to the central region. Using the CH4Off narrow/medium-band and H broad band filters in the Wide Infrared Camera (WIRCam) on the Canada-France-Hawaii Telescope (CFHT), we constructed a sample of objects that show a flux excess in the CH4Off band due to line emission. The emission line flux is ~ 4.9 × 10^-16 erg s^-1 cm^-2, corresponding to a star formation rate (SFR) of ~ 50 M_⊙ yr^-1 for galaxies at redshifts z ~ 1.4. None of the galaxies with medium-band flux excess is located within 1 Mpc from the central AGN, and there is no evidence that the selected galaxies are associated with the proposed cluster. Along with the star formation quenching near the center that was found from the previous grism observations, the lack of extreme starbursts in the structure suggests that at z ~ 1.4, overdense regions are no longer favorable locations for vigorous star formation.

• 한국분말재료학회지
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• 제17권5호
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• pp.365-372
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• 2010

The evolution of sinterability, microstructure and mechanical properties for the spark plasma sintered(SPS) Ti from commercial pure titanium(CP-Ti) was studied. The densification of titanium with 200 mesh and 400 mesh pass powder was achieved by SPS at $750{\sim}1100^{\circ}C$ under 10 MPa pressure and the flowing $H_2$+Ar mixed gas atmosphere. The microstructure of Ti sintered up to $800^{\circ}C$ consisted of equiaxed grains. In contrast, the growth of large elongated grains was shown in sintered bodies at $900^{\circ}C$ with the 400 mesh pass powder and the lamella grains microstructure had been developed by increasing sintering temperature. The Vickers hardness of 240~270 HV and biaxial strength of 320~340 MPa were found for the specimen prepared at $950^{\circ}C$.

• 한국미생물·생명공학회지
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• 제48권2호
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• pp.230-235
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• 2020

The global evolution of antibiotic resistance has threatened the efficacy of available treatment options with ravaging impacts observed in developing countries. As a result, investigations into the prevalence of antibiotic resistance and the role of plasmids are crucial. In this study, we investigated the presence and distribution of bla_TEM and gyrA genes, plasmid profiles, and the antimicrobial susceptibility pattern of Salmonella strains isolated from raw meat and stool sources across Niger State, Nigeria. Ninety-eight samples, comprising 72 raw meat and 26 stool samples, were screened for Salmonella spp. The antimicrobial susceptibility of Salmonella isolates to 10 commonly used antimicrobial agents was determined using the KirbyBauer disc diffusion method. Isolates were further analyzed for plasmids, in addition to PCR amplification of beta-lactamase (bla_TEM) and gyrA genes. A total of 31 Salmonella spp. were isolated, with 22 from raw meat (70.97%) and 9 from stool (29.03%). Salmonella spp. with multiple resistance patterns to ceftazidime, cefuroxime, ceftriaxone, erythromycin, ampicillin, cloxacillin, and gentamicin were detected. Ofloxacin and ciprofloxacin were found to be the most effective among the antibiotics tested, with 67.7% and 93.5% susceptible isolates, respectively. Nine (29.03%) isolates harbored plasmids with molecular sizes ranging between 6557 bp and 23137 bp. PCR amplification of gyrA was detected in 1 (3.23%) of the 31 isolates while 28 isolates (90.32%) were positive for bla_TEM. This study shows the incidence of antibiotic resistance in Salmonella isolates and the possible role of plasmids; it also highlights the prevalence of ampicillin resistance in this local population.

• Parasites, Hosts and Diseases
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• 제59권1호
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• pp.103-108
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• 2021

To date, there is no report on the genetic diversity of ticks in these regions. A total of 370 representative ticks from the south and east regions of Kazakhstan (SERK) and Xinjiang Uygur Autonomous Region (XUAR) were selected for molecular comparison. A fragment of the mitochondrial cytochrome c oxidase subunit I (cox1) gene, ranging from 631 bp to 889 bp, was used to analyze genetic diversity among these ticks. Phylogenetic analyses indicated 7 tick species including Hyalomma asiaticum, Hyalomma detritum, Hyalomma anatolicum, Dermacentor marginatus, Rhipicephalus sanguineus, Rhipicephalus turanicus and Haemaphysalis erinacei from the SERK clustered together with conspecific ticks from the XUAR. The network diagram of haplotypes showed that i) Hy. asiaticum from Almaty and Kyzylorda Oblasts together with that from Yuli County of XUAR constituted haplogroup H-2, and the lineage from Chimkent City of South Kazakhstan was newly evolved; and ii) the R. turanicus ticks sampled in Israel, Almaty, South Kazakhstan, Usu City, Ulugqat and Baicheng Counties of XUAR were derivated from an old lineage in Alataw City of XUAR. These findings indicate that: i) Hy. asiaticum, R. turanicus and Ha. erinacei shared genetic similarities between the SERK and XUAR; and ii) Hy. marginatum and D. reticulatus show differences in their evolution.

• 자원환경지질
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• 제41권1호
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• pp.15-32
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• 2008

강화 석모도 지역 석모도 온천수의 영족기체와 온천수의 지화학적 진화와 기원을 해석하고 온천수의 지화학적 특성을 규명하기 위해 온천수, 지하수, 지표수의 수리화학, 안정 동위원소, 영족기체 동위원소 분석이 이루어졌다. 온천수와 지하수의 pH는 각각 $6.42{\sim}6.77,\;6.01{\sim}7.71$로 약산성을 보이고 있다. 석모도 온천 지역의 온천수의 유출수온은 $43.3{\sim}68.6^{\circ}C$이다. 온천수의 전기전도도는 $60,200{\sim}84,300{\mu}S/cm$으로 비교적 높은 값이며 석모도 온천수가 해수와 혼합되어졌음을 암시하고 있다. 석모도 온천수의 화학 조성은 Na-Ca-Cl형이다. 반면, 지하수와 지표수는 각각 Na(Ca)-$HCO_3$, Na(Ca)-$SO_4$형과 Ca-$HCO_3$ 형으로 구분된다. 석모도 온천수의 산소와 수소 동위원소비는 각각 $-4.41{\sim}-4.47%o$와 $-32.0{\sim}-33.5%o$로 순환수 기원이다. 지하수에서의 산수 수소 동위원소비는 각각 $-7.07{\sim}-8.55%o,\;-50.24{\sim}-59.6%o$이다. 석모도 온천수에 $^{18}O$와 $^2H$가 부화된 특성은 온천수가 담수와 해수의 혼합대에서 유래되었음을 암시하고 있다. 석모도 온천수 중의 황산염이온의 황 동위원소비는 $23.1{\sim}23.5%o$로 이 지역 해수의 황 동위원소비(20.2%o)와 유사하다. 이는 온천수의 황이 해수의 황산염으로부터 유래되었음을 의미한다. 석모도 온천수의 $^3He/^4He$ 비는 $1.243{\times}10^{-6}{\sim}1.299{\times}10^{-6}cm^3STP/g$로 온천수 중의 He 가스가 부분적으로 맨틀에서 유래되었음을 보여준다. 온천수에서의 아르곤 동위원소비$(^{40}Ar/^{36}Ar=298{\times}10^{-6})cm^3STP/g$는 대기기원의 값을 보인다.

• 생명과학회지
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• 제18권2호
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• pp.264-272
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• 2008

풀망둑(Acanthogobius hasta) 조직의 젖산탈수소효소(EC 1.1.1.27 Lactate dehydrogenase, LDH) 동위 효소의 특성을 생화학적, 면역화학적 및 역학적 방법에 의해 연구하였다. 풀망둑 골격근과 눈 조직의 젖산탈수소효소 활성이 65.30과 53.25 units였고, 심장과 간 조직에서는 낮게 나타났다. 골격근 조직의 LDH/CS는 22.29로 가장 높고, LDH 특이활성도는 뇌 56.45, 눈 38.04 및 골격근 11.04 units/mg였다. 각 조직에 대해 $A_4,\;B_4$, eye-specific $C_4$, 및 liver-specific $C_4$에 대한 항혈청으로 면역 침강 반응시킨 후 Polyacrylamide gel 전기영동 하였다. 골격근, 뇌 및 눈 조직에서 $A_4$ 동위효소가 우세하게 확인되었고, 심장에서는 $A_4$ 동위효소가 확인되었다. 또한 양극의 eye-specific t와 음극의 liver-specific $C_4$가 한 종에서 함께 발현되었으며, 눈 조직의 eye-specific $C_4$는 활성이 크고 간 조직의 liver-Specific $C_4$의 활성은 낮게 나타났다. 결과 $A_4$와 $C_4,\;A_4$와 $B_4$ 및 eye-specific $C_4$와 liver-specific $C_4$의 분자구조의 일부가 서로 유사하지만 $B_4$와 $C_4$의 구조는 서로 다른 것으로 나타났으므로 하부단위체 A는 보존적이고 하부단위체 B는 하부단위체 A보다 빠르게 진화된 것으로 사료된다. 골격근 조직의 LDH $A_4$ 동위효소는 affinity chromatography에서 $NAD^+$를 함유한 buffer를 유입한 후 용출된 분획에서 정제되었고, eye-specific $C_4$ 동위효소는 $A_4$ 분획에 이어 용출되었으므로 eye-specific $C_4$가 $A_4$의 분자 구조와 유사한 것으로 보인다. 그리고 LDH에 대한 피루브산의 저해 실험 결과 35.22-43.47% 의 활성이 남았고, $Km_{pyr}$은 0.080-0.098 mM이고 골격근과 눈조직의 Vmax은 153.85와 35.09 units였다. 또한 $B_4$ 동위효소가 열에 대해 가장 안정하였고 $C_4$는 $A_4$보다 안정하였으며, 최적 pH는 6.5로 나타났다. 본 실험 결과 풀망둑은 저 산소 환경조건에 적응되어져 조직들의 동위효소들이 $A_4$와 $B_4$ 동위효소 사이의 특성을 나타냈고, 골격근과 눈 조직에서 피루브산에 대한 LDH의 친화력이 상당히 크므로 LDH가 혐기적 조건에서 효율적으로 기능을 하는 것으로 사료된다.