• The Journal of the Petrological Society of Korea
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• v.26 no.3
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• pp.281-295
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• 2017

We determined chemical compositions like abundance of major and trace elements, Sr and Nd isotope compositions for two tektites from the Thailand and Vietnam. Their chemical compositions are similar to each other, and seem to be similar to those of PAAS (Post Archean Australian Shale) rather than upper continental crust. In particular, primitive mantle-normalized spider diagrams and chondrite-normalized REE patterns for two tektites are the same, suggesting that they might be derived from the same source material. The $^{87}Sr/^{86}Sr$ and $^{143}Nd/^{144}Nd$ ratios from Thailand tektite are $0.718870{\pm}0.000008(2{\sigma}_m)$ and $0.512024{\pm}0.000012(2{\sigma}_m)$, respectively, and those from Vietnam are $0.717022{\pm}0.000008(2{\sigma}_m)$ and $0.511986{\pm}0.000013(2{\sigma}_m)$, respectively. The $^{87}Sr/^{86}Sr$ and $^{143}Nd/^{144}Nd$ ratios from Thailand tektite are slightly enriched than those of Vietnam tektite. $^{87}Sr/^{86}Sr$ ratios from the Vietnam and Thai tektites were plotted on the range of Australasian tektites reported previously. $^{143}Nd/^{144}Nd$ ratio of Vietnam tektite from this study was lower than the range of $^{143}Nd/^{144}Nd$ ratio from the Australasian tektite reported previously whereas that of Thai tektite was included in the range of $^{143}Nd/^{144}Nd$ ratio from the Australasian tektite. The geochemical characteristics from two tektites in this study indicate that they may be derived from the very similar source materials.

• The Korean Journal of Mycology
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• v.3 no.1
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• pp.1-19
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• 1975

Since the importance of casing in fruit body formation of Agaricus bisporus has been emphasized, physico-chemical characteristics of casing materials were discussed by many workers and a mixture of peat and mineral soil as proper casing material has been adopted in many of mushroom growing countries. Because of limited resources of peat in Korea, it is necessary to find practical performance and substitutional materials for casing. The effect of casing on mycelial growth and mushroom yield of A. bisporus varied with materials, its combination and practices etc. The experiments to be discussed in this paper are concerned with pH and Ca of casing material which influence A bisporus, and changes of physico-chemical characteristics with mixing ratio of casing materials and its effect on A. bisporus. The optimum range of moisture content of each material, management of watering and application of physico-chemical characteristics casing materials was also investigated and re-use of weathered spent compost for casing material was described. 1. The effect of calcium on mycelial growth of A. bisporus at various pH in Halbschalentest showed different results with calcium sources. Best results were obtained around neutrality and fresh weight of fruit bodies grown in the range of pH 7 to 8 was highest among the tested levels. 2. Available moisture, pore space, organic matter, cation exchangeable capacity and exchangeable cation was increased by an increase of mixing ratio of peat in casing materials, while an adverse effect was obtained by addition of sand. 3. Mycelial growth on clay loam was more rapid at a lower bulk density of 0.75g/cc and at 20% moisture content on a dry weight basis at the same bulk density. 4. Mixing ratio of casing materials, 60 to 80 per cent by volume of peat mixed with 20 to 40 per cent of clay loam produced the highest yield of fresh fruit bodies and sand the lowest. However, per cent of open cap was highest in peat and lowest in sand. 5. Days required for fruit body initiation was shortened in mixtures of peat and clay loam by one to three days compared with other materials and the formation of flushes was clear. 6. The effect of some physico-chemical characteristics of casing materials on the fresh weight of fruit bodies were estimated by a multiple regression equation; Y=-923.86+$8.18X_1+8.04X_2+7.90X_3+0.12X_4+2.03X_5-0.82X_6-0.54X_7$ where $X_1,X_2,X_3,X_4,X_5,X_6,X_7$ are sand, silt, clay, available moistuer, porosity, organic matter and exchangeable cation respectively. The productivity of certain casing material could be predicted from this equation. 7. Fresh weight of fruit bodies was positively correlated with porosity exchangeable cation, organic matter, available moisture, silt and clay of materials; while sand was negatively correlated. On the contrary, sand was the unique factor reducing per cent of open cap. 8. Distribution of three phases of high productive casing material was concentrated in the range of 10 to 30 per cent solids, 15 to 30 per cent liquids, and 50 to 60 per cent in air volume. 9. Fresh weight of fruit bodies from peat was not affected with heavy watering but in clay loam and sandy loam severe crop losses occurred. Fresh weight of individual fruit was increased and open caps were decreased with heavy watering but light watering resulted in adverse effects: its effect was especially great in peat. 10. Optimum range of moisture content by weight on a dry basis was different with each casing material. To maintain optimum moisture content concerned with yield of fruit bodies and open cap, sandy loam and peat mixtures required daily watering of 0.6, 0.6 to 1. 2 and 1.2 to 2.4 liters per $3.3m^2$ of bed area, respectively. 11. Maximum yield of fruit body was recorded in the range of pF 2. 0 to 2. 5 of casing materials if organic matter content was below 4.2 per cent and in pF 1. 3 to 1.8 if above 7.1%. 12. pF curve of a certain casing material could be draws from moisture content at various pF values by multiple regression equations provided texture, organic matter and calcium of the casing material are given. Optimum moisture range of the casing materials also could be estimated by the equation. 13. It was possible to improve the phyico-chemical characteristics of clay loam and sandy loam by addition of weathered spent compost although the effect was less than in the case of peat. Fresh weight of fruit bodies wsa increased by addition of weathered spent compost but its effect was not as remarkable as peat. Accordingly, further studies will be required.

• Journal of the Korean Chemical Society
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• v.17 no.2
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• pp.95-104
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• 1973

Ground electronic structures and SNreactivities of a series of alkylchlorides (methyl,ethyl, iso-propyl, trans n-butyl, sec-butyl, tert-butylchloride) have been studied using approximate $({\sigma}-MO)$ method, such as EHT and CNDO/2. It was found that CNDO/2 gives better results for the systems such as alkylchlorides whose structural differences are not remarkable, in comparison with EHT method. According to CNDO/2 results, calculated dipole moments for alkylchlorides are slightly higher than observed values, showing the order of primary < secondary < tertiary alkylchlorides. It was also found that highest occupied(HO) MO's are completely or nearly degenerate, and show relatively weak $\pi$-antibonding nature between$\alpha$-carbon and Cl atoms. Furthermore, the electrons in this MO are largely confined to Cl atom, and hence these behaves as likely as p-lone pair electrons of Cl atom. On the contrary, lowest unoccupied (LU) MO's show strong $\sigma$-antibonding nature between $\alpha$-carbon and Cl atoms whose electron clouds are directed along the C-Cl axis. It has been discussed that the$S_N2$ reactivities of alkylchlorides may largely be controlled by ${\sigma}^{\ast}$ LUMO, and the antibonding strength between $\alpha$-carbon and Cl atoms in this MO may become the measure of $S_N2$reactivity. The relationship between $S_N2$reactivity and C-Cl bond polarizability has also been discussed. It has been suggested that the unique structure factors determining $S_N1$reactivities may be $\pi$-antibonding strength between $\alpha$-carbon and Cl atoms in HOMO and C-Cl bond strength in ground state.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.5
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• pp.431-438
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• 2000

To clarify the annual reproductive cycle in a rockfish, Sebastes schlegeli, monthly changes in gonadosomatic index (GSI), hepatosomatic index (HSI) and histological feature of gonads and plasma levels of sex steroid hormones ($estradiol-l7{\beta},\;17{\alpha},\;20{\beta}-dihydroxy-4-pregnen-3-one,\;testosterone\;and\;11-ketotestosterone$) were investigated. The annual reproductive cycle in females could be divided into 5 periods as follows: 1) recovery period (June to September): serum level of $estradiol-l7{\beta}$ increased gradually; 2) vitellogenesis period (Septemer to february) : vitellogenic oocytes were obsewed, GSI sustained high value, and serum level of $estradiol-l7{\beta}$ increased; 3) gestation period (February-April): developing larva showed in the ovary, and serum levels of $17{\alpha},\;20{\beta}-dihydroxy-4-pregnen-3-one$ and testosterone increased; 4) partrition period (April to May) : larva were delivered, and value of GSI and serum levels of hormones decreased rapidly; 5) resting period (May to June) : value of GSI and serum levels of $estradiol-l7{\beta}$ and testosterone remained low. The annual reproductive cycle in males could be divided into 6 periods; 1) early maturation period (April to June): value of GSI and serum levels of hormones incresed gradually, cyst of spermatogonia incresed in number, and a small number of cyst of spermatocyte was observed; 2) mid-maturation perid (June to September); value of GSI and serum levels of hormones increased, and germ cells in many cysts were undergoing active sperrnatogenesis; 3) late maturation period (September to November) : value of GSI and serum levels of hormones remained high and spermatozoa were released into the lumina of the seminal lobules; 3) spermatozoa dischaging period (Nobember to December) : the lumina of the seminal lobules were enlarged and filled with mature spermatozoa; 4) degeneration period (December to Februauy)i value of GSI decresed and cyst of spermatocyte were decresed in number; 5) resting period (December to April) : no histological changes of testes were observed, and value of GSI and serum levels of hormones remained low. In November, the lumina of the seminal lobules were filled with mature spermatozoa and sperm masses were present in the ovarian cavity. Thus, copulation in this species occurred in November and December.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.5
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• pp.439-477
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• 2000

Seasonal variation in species composition of fishes in the eelgrass bed in Angel Bay of the southern coast of Korea was determined using monthly samples by a beam trawl from April 1998 to March 1999, A total of 39 species, 2,065 individuals and 8,930 g of fishes were collected during the study period. The fish were composed of the small-sized resident species and the juveniles of Leiognathus nuchalis, Pholis nebulosa, Spgnathus schlegeli and Sebastes ineinis predominated in abundance, accounting for $60{\%}$ of total number of individuals. The number of species and biomass were low from December to March when the water temperature was low, The biomass increased by the catch of a large number of L. nuchalis and S. inemis in April and May when the eelgrass grew fast. The fish numbers decreased in June and July when the adults of the resident species declined after the spawning. A large number of juveniles which had released in spring occurred in August. The biomass of fish decreased from September, and a few number of fish were collected in winter. Species were grouped into four by cluster analysis: the warm season group including P. nebulosa, S. schlegeli and L. nuchalis, the cold season group including Chaenogobius heptaoanthus and Platycephalus indieus, the group of fish species occurred during the growing season of eelgrass such as P. couoides, S. inermis and P. perooides, and the group of fish species occurred during decaying season of eelgrass such as S. cirrhifer and H. coronatus. Principal component analysis indicated that seasonal variation in species composition was determined by the water temperature and standing crops of eelgrass.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.5
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• pp.448-454
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• 2000

This study was to examine the physicochemical characteristics of coagulation reaction between ignited oyster shell powder (IOSP) and red tide organisms (RTO), and its feasibility, in developing a technology for the removal of RTO bloom in coastal sea,IOSP was made from oyster shell and its physicochemical characteristics were examined for particle size distribution, surface characteristic by scanning electron microscope, zeta potential, and alkalinity and pH variations in sea water. Two kinds of RTO that were used in this study, Cylindrotheca closterium and Skeletonema costatum, were sampled in Masan bay and were cultured in laboratory. Coagulation experiments were conducted using various c(Incentrations of IOSP, RTO, and a jar tester. The supernatant and RTO culture solution were analyzed for pH, alkalinity, RTO cell number, IOSP showed positive zeta potentials of $11.1{\~}50.1\;mV\;at\;pH\;6.2{\~}12.7$, A positive zeta potential of IOSP slowly decreased with decreasing pNa 4,0 to 2,0. When pNa reached zero, the zeta potential approached zero, When a pMg value was decreased, the positive zeta potential of IOSP increased until pMg 3.0 and decreased below pMg 3.0. IOSP showed 4.8 mV of positive zeta potential while RTO showed -9.2 mV of negative zeta potential in sea water. A positive-negative EDL (electrical double-layer) interaction occurred between $Mg(OH)_2$ adsorption layer of IOSP and RTO in sea water so that EDL attractive force always worked between them. Hence, their coagulation reaction occurred at primary minimum on which an extreme attractive force acted because of charge neutralization by $Mg(OH)_2$ adsorption layer of IOSP. As a result, the coagulation reaction was rapidly processed and was irreversible according to DLVO (Deriaguin-Landau-Verwey-Overbeek) theory. Removal rates of RTO were exponentially increased with increasing both IOSP concentration and G-value. The removal rates were steeply increased until 50 mg/l of IOSP and reached $100{\%}\;at\;400\;mg/l$ of IOSP. Removal rates of RTO were $70.5,\;70.5,\;81.7,\;85.3{\%}$ for G-values of $1,\;6,\;29,\;139\;sec^(-1)$at IOSP 100 mg/l, respectively. This indicated that mixing (i.e., collision among particles) was very important for a coagulation reaction.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.5
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• pp.463-468
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• 2000

This study was conducted to investigate the effects of Kluyveromyces fragilis, Candida utilis and brewer's yeast as an additive in formulated diets containing different fish meal levels ($55{\%} and 45{\%}$) on growth and body composition of juvenile Korean rockfish (Sebastes schlegeli). Juvenile rockfish (average weight, 2.6 g) were distributed into 24 tanks with 3 replication groups and fed eight isoproteic ($41{\%}$) and isolipidic ($11{\%}$) diets containing each level ($3{\%}$) of K. frayilis, C. utilis and brewer's yeast as an additive. Survival rate of fish was not affected by dietary fish meal level and yeast kind (P > 0.05). Weight gain of fish fed the control and diets containing C. utilis and brewer's yeast was not influenced by fish meal level (P > 0.05), Weight gain of fish fed the $55{\%}$ fish meal diet containing C. utilis and $45{\%}$ fish meal diets containing K. fragilis and C. utilis was lower than that of fish fed the control diet (P < 0.05). Feed efficiency and protein efficiency ratio of fish fed the control and diet containing brewer's yeast were not affected by fish meal level, but these value of fish fed the diets containing K, fragilis and C. utilis were lower in $45{\%}$ fish meal diets than in $55{\%}$ fish meal diets. Hepatosomatic index and liver lipid content of fish fed the diet containing C. utilis were decreased regardless of fish meal level (P < 0.05), Hemoglobin, hematocrit, red blood cell, plasma total protein and plasma total glucose were not affected by dietary fish meal levels and yeast supplements (P > 0.05). From the above results, it can be concluded that yeast supplement in this formulated diet for growth of juvenile rockfish is not necessary.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.4
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• pp.348-355
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• 2000

This paper described the relationship between the behavior of the Israeli carp, Cyprinus carpio and the environmental noise level due to the dynamite explosion work. The experiment was conducted in the cage ($L10{\times}W4{\times}D4 m$) of aquaculture located at Chungjoo Lake, Chechon, in 1997. The fish trajectory was obtained by the telemetry system in which a pulsed ultrasonic pinger ($50 kHz, {\phi}16{\times}L70 mm$) attached to the fish was tracked three dimensionally, and the underwater noise levels were measured. The results of the study were as follows: 1. The underwater noise levels in the normal blasting measured at a distance of 400 m from the source of noise increased by $40 dB (re 1 {\mu}Pa)$ compared to the levels before explosion. The dominant frequency and the increased power spectrum level of the underwater noise by the explosion work were $75 to 100 Hz and 22.9 to 35.3 dB$, respectively. 2. The underwater noise levels in the test blasting measured at a distance of 350 m from the source of noise increased by average $49.5 dB (re 1 {\mu}Pa)$compared to the levels before explosion. 3. The swimming area of the fish was reduced with the time after explosion, and after more than one hour the fish represented the similar swimming area and behavior to the status of right before explosion. 4, The swimming depth layer of the fish was most of the case at the sea surface less than 1,0 m except during explosion or right after of it. But the fish swam downward when an external stimulus like the explosion noise was given to the fish. 5. The average swimming speeds of the fish before, during and after the works were about 1.2 times, 1.9 times and 1.0 times of the body length, respectively, and the speed of the fish with explosion was faster 1.6 times than the speed without of that. Consequently, the explosion noise levels measured by this study were sufficiently high to affect the fish, and the heavy shock by the explosion works could produce a considerable unfavorable effects to the fish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.5
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• pp.378-382
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• 2000

The effects of bisphenol A (BPA), known as one of the endocrine disrupting chemicals (EDCs), on the hatching of fertilized eggs (FE) and the spawning of adult fish in songsari, Oryzias latipes were investigated. In condition of the experimental groups, incubated water temperature was $25.0{\pm}0.5^{\circ}C$ and photoperiod was 16 h (light) : 8 h (dark). fE were exposed to aqueous solutions of BPA at nominal concentration of 50, 100 and $200 {\mu}g/l$. The time required in hatching of FE was long in the BPA $50 and 100 {\mu}g/l$ treatment groups when compared to the controls, and in the BPA $200 {\mu}g/l$ treatment group, FE failed to hatch. And also hatching rate was decreased in the BPA treatment groups in comparison to the controls, Adult fishes were reared to oral administration via a diet of 50, 100 and $200 {\mu}g/g$ body weight BPA concentration for 3 weeks, Number of total eggs spawned in the adult fish were fewer in the BPA 100 and 200 treatment groups than in the controls and BPA 50 treatment group. Frequency of abnormal eggs in the total eggs spawned was 11.8 and $16.2{\%}$ in the control and acetone carrier control lower than 36.8, 46,8 and $74.1{\%}$ in the BPA 50, 100 and 200 treatment groups, respectively. And hatching rate of FE decreased in the BPA treatment groups in comparison to the controls. In these results, inhibition of the hatching of FE and the quantity and quality of spawned eggs in adult fish were observed from BPA treatment groups when compared to the controls.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.4
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• pp.273-279
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• 2000

The influence of different storage temperature and packaging methods on plain dried anchovy were investigated. When plain dried large anchovy (DLA) was stored at $-20^{\circ}C, 5^{\circ}C and 2^{\circ}C$, the lipid oxidation was rapidly progressed with the increased temperature. When DLA was stored at $25^{\circ}C and 5^{\circ}C$, peroxide value (POV) reached to maximum on 4 days and 20 days, respectively, while POV increased progressively during storage at $-25^{\circ}C$. The degree of lipid oxidation was progressed the fastest in DLA packed in polyethylene film, followed by packing with oxygen absorber and packing in vacuum. The fatty acid composition of total lipid in DLA revealed $52.3{\%}$ in polyenes, $29.2{\%}$ in saturates and 1$8.5{\%}$ in monoenes, and the major fatty acids were 22 : 6, 20 : 5, 16 : 0, 16 : 1 and 18: 1. Saturates were increased with the rise of storage temperature and prolonging the storage period, while polyenes were decreased. The changes of fatty acid composition was retarded at lower temperature. And the changes of fatty acid composition were the lowest in DLA by vacuum packing, followed by packing with oxygen absorber and packed in polyethylene film. The contents of highly unsaturated fatty acid of polyenes were decreased remarkably in proportion to the progress of lipid oxidation, while saturates were increased.