• Journal of Life Science
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• v.31 no.3
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• pp.314-320
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• 2021

In the present study, we investigated the effect of photoperiod and water temperature on the gonadosomatic index (GSI), histological stage of the testes, and plasma levels of sex steroid (testosterone, T; 11-ketotestosterone, 11-KT) hormones in cultured male small yellow croakers (Larimichthys polyactis). In a photoperiod experiment, small yellow croakers were reared under a natural photoperiod (NP, 10L:14D-11L:13D), long photoperiod (LP, 14L:10D), and short photoperiod (SP, 10L:14D) at 17℃ for 90 days. The GSI was significantly higher in the LP group than in the other groups at 30 and 60 days. The plasma 11-KT levels were significantly higher in the LP group than in the other groups at 30 days. In a water temperature experiment, small yellow croakers were reared under natural water temperature (NT, 19.1-15.0℃), or at 17℃, 21℃, or 25℃ under a LP (14L:10D) for 60 days. The GSI was significantly lower for the 25℃ group than for the other groups at 30 and 60 days. The plasma 11-KT levels were significantly lower for the 25℃ group than for the other groups at 60 days. Therefore, the sexual maturation of cultured male yellow croakers was promoted by LP and inhibited at water temperatures above 25℃. These findings suggest that the sexual maturation of cultured male small yellow croakers is controlled by both the photoperiod and the water temperature.

• Korean Journal of Crystallography
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• v.8 no.2
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• pp.119-123
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• 1997

The complex [Ni(L)]I2 (1) (L:3,5,10,12-Tetramethly-1,4,8,11-tetraazacyclotetradecane) has been prepared and characterized by X-ray diffraction methods. The complex 1 crystallized in the orthorhombic system, space group Pcab with cell parameters a=13.293(1) Å, b=28.550(7) Å, c=10.804(1) Å, z=8. Least-squares refinement of 1 led to a R(Rw) factor of 0.043 (0.046) for 1851 observed reflections of Fo>3o (Fo). The crystal structure of 1 has a slightly distorted square-planar geometry and adopts the trans-III conformation.

• Korean Journal of Crystallography
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• v.9 no.1
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• pp.6-10
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• 1998

The complex[Cu(L)](ClO4)2 (1) (L:3,5,10,12-Tetramethyl-1,4,8,11-tetraazacyclotetradecane) has been synthesized and structurally characterized. The complex 1 crystallizes in the monoclinic system, space group P21/n with cell parameters a=8.208(2)Å, b=13.339(6) Å, c=10.752(5) Å, β=111.02(4)˚ Z=2. Least-squares refinement of 1 led to a R(RW)factor of 0.073 (0.142) for 617 observed reflections of F0>40(F0). The crystal structure of 1 has a square-planar geometry and adopts the trans-III conformation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.1
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• pp.21-30
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• 1991

In Summer, oxygen-deficient water masses were developed extensively in the closed eutrophic bays such as Chinhae Bay which results in mass mortality of marine organisms and severe decrease the production of the bay every year. Under the circumstances, this study was performed to investigate the oxygen depletion relating to eutrophication, and also to evaluate self-purfication capacity of Buk Bay by dissolved oxygen mass balance in 1988. The mean concentration of total inorganic nitrogen, phosphate phosphorus and chlorophyll-a were $11.06{\mu}g-at/l,\;0.80{\mu}g-at/l\;and\;1.11mg/m^3$ respectively, which were over eutrophication criteria. Oxygen-deficient water mass was formed in July with the minimum concentration of 2.08ml/l(mean) at the bottom of all stations and recovered slowly in August. The decay and reaeration coefficient calculated from dissloved oxygen sag curve were 0.222/day and 0.018ml/l/day, respectively. To maintain above 4ml/l of oxygen to prevent oxygen-deficient water mass, it is recommendable to supply as much as 0.856ml/l/day of dissolved oxygen or should be reduced the same mass loading of BOD from watershed by the construction of wastewater treatment plant.

• Journal of the Korean Institute of Gas
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• v.9 no.1 s.26
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• pp.16-20
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• 2005

CFC-11 and HCFC-l4lb have been used as blowing agents for rigid polyurethane foam insulation of LNG storage tank. But CFC-11 and HCFC- l4lb deplete ozone layer in the stratosphere. So in leading countries, the use of CFC-11 has been prohibited since 1995 and the use of HCFC-l4lb will be prohibited from 2005. Much efforts and studies have been done about alternative blowing agents and insulations blown by alternative blowing agents. This paper deals with polyurethane foams (PUFs) blown by HFC-365mfc, shows their physical and mechanical characteristics and thermal performance. These data are compared with the results of PUFs blown by HCFC-l4lb. From these test results, PUFs blown by HFC-365mfc show good mechanical and thermal characteristics. It is possible to use PUFs blown by HFC-365mfc as main insulation of membrane type LNG storage tank.

• Journal of Astronomy and Space Sciences
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• v.2 no.2
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• pp.101-115
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• 1985

Using Brandt model the mess distribution of the late type spiral galaxy NGC 6946 was derived, and the total mass was reestimated to understand the M/L ratio of this galaxy. Two kinds of the rotation curve with shape parameter n=1 and 3.3 were examined. The following are the main results; (1) The total masses of NGC 6946 are $3.1\times$$10^{11}$ M(n=1) AND $2.8\times$$10^{11}$ M(n=3.3) respectively. and the corresponding M/L are about 17 and 16 for both cases. (2) The optical image in the blue light, whose radius is 9.6 kpc, has 8$\times$$10^{10}$ M and 1.4$\times$$10^{11}$ M. These give the value of M/L about 5 and 8 respectively. (3) The masses and M/L of the nuclear region within 1.2 kpc are 4.0$\times$$10^{9}$ M 4.7$\times$$10^9$ M and 3, 4 for both cases. Those of the disk from 1.2 kpc to 9.6 kpc are 7.6$\times$1$10^{10}$M, 1.4$\times$$10^{11}$M, and 5, 8. (4) The masses of the outer halo extended to few hundreds kiloparsecs are 2.3$\times$$10^{11}$ M and 1.4$\times$$10^{11}$M. The corresponding M/L are about 62 and 37.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.11
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• pp.11-80
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• 1972

• Bulletin of the Korean Chemical Society
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• v.20 no.11
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• pp.1257-1260
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• 1999

• Microbiology and Biotechnology Letters
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• v.34 no.4
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• pp.338-341
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• 2006

The growth characteristics of sulfur-oxidizing bacteria, Acidithiobacillus thiooxidans AZ11, MET, and TAS were investigated in mineral salt media supplemented with elemental sulfur of 1$\sim$50 g $L^{-1}$. The sulfur oxidation rates of A. thiooxidans. MET and TAS increased highly with increasing sulfur concentration up to 10 g L$^{-1}$, but the rates increased slowly in sulfur concentration over 10 g L$^{-1}$. A. thiooxidans AZ11 showed the parallel increase of sulfur oxidation rate until sulfur concentration increased up to 40 g L$^{-1}$. The maximum sulfur oxidation rates (V$_{max}$) of AZl1, MET and TAS were 1.88, 1.38 and 0.43 g S L$^{-1}$ d$^{-1}$, respectively. The maximum specific growth rates (${\mu}_{max}$) of AZ11, MET, and TAS were 0.33 d$^{-1}$, 0.30 d$^{-1}$ and 0.45 d$^{-1}$, respectively. Although MET and TAS couldn't grow at sulfate concentration of 40 g L$^{-1}$, AZ11 could grow in the presence of 58 g L$^{-1}$ sulfate, the final oxidation product of elemental sulfur.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.8
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• pp.472-479
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• 2015

This study was investigated occurrence and distribution patterns of UV filters in Nakdong River basin (mainstream, tributaries and sewage treatment plant (STP) effluents). 5 (EHS, BP-3, 4-MBC, BZC and EHMC) out of 7 UV filters were detected in 5 out of 20 sampling sites (mainstream and tributaries), 7 UV filters were not detected in mainstream samples, and the EHS, BP-3, 4-MBC, BZC and EHMC concentration levels in tributary samples were ND~60.8 ng/L, ND~72.1 ng/L, ND~57.2 ng/L, ND~60.1 ng/L and ND~85.2 ng/L, respectively. 5 (EHS, BP-3, 4-MBC, BZC and EHMC) out of 7 UV filters were detected in effluents of 11 STPs around the Nakdong River basin. The EHS, BP-3, 4-MBC, BZC and EHMC concentration levels in 11 STP effluents were ND~89.3 ng/L, ND~90.8 ng/L, ND~88.1 ng/L, ND~118.5 ng/L and ND~104.4 ng/L, respectively. According to the sampling season, distribution patterns and detected concentrations of 5 UV filters were similar in June and September 2014, but change ranges of distribution patterns and detected concentrations of 5 UV filters were highly variable in April and November 2014.