• Korean Journal of Mineralogy and Petrology
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• v.35 no.3
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• pp.313-331
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• 2022

Natural or native abiotic molecular hydrogen (H₂) is a major component in natural gas, however yet its importance in the global energy sector's usage as clean and renewable energy is underestimated. Here we review the occurrence and geological settings of native hydrogen to demonstrate the much widesprease H₂ occurrence in nature by comparison with previous estimations. Three main types of source rocks have been identified: (1) ultramafic rocks; (2) cratons comprising iron (Fe²⁺)-rich rocks; and (3) uranium-rich rocks. The rocks are closely associated with Precambrian crystalline basement and serpentinized ultramafic rocks from ophiolite and peridotite either at mid-ocean ridges or within continental margin(Zgonnik, 2020). Inorganic geological processes producing H₂ in the source rocks include (a) the reduction of water during the oxidation of Fe²⁺ in minerals (e.g., olivine), (b) water splitting due to radioactive decay, (c) degassing of magma at low pressure, and (d) the reaction of water with surface radicals during mechanical breaking (e.g., fault) of silicate rocks. Native hydrogen are found as a free gas (51%), fluid inclusions in various rock types (29%), and dissolved gas in underground water (20%) (Zgonnik, 2020). Although research on H₂ has not yet been carried out in Korea, the potential H₂ reservoirs in the Gyeongsang Basin are highly probable based on geological and geochemical characteristics including occurrence of ultramafic rocks, inter-bedded basaltic layers and iron-copper deposits within thick sedimentary basin and igneous activities at an active continental margin during the Permian-Paleogene. The native hydrogen is expected to be clean and renewable energy source in the near future. Therefore it is clear that the origin and exploration of the native hydrogen, not yet been revealed by an integrated studies of rock-fluid interaction studies, are a field of special interest, regardless of the presence of economic native hydrogen reservoirs in Korea.

• Korean journal of applied entomology
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• v.61 no.3
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• pp.423-434
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• 2022

The two previously developed artificial diets (N4 and N6) used for rearing Spodoptera frugiperda (Noctuidae) larvae, were selected as highly-fit ones for rearing Mythimna loreyi larvae. Almost all biological characteristics were not significantly different between the colonies reared on the two diets at 25℃ and 15:9 h (light:dark) photoperiod. The developmental periods were 4.9-5.2 days for eggs, and 22.3-23.2 days for larvae. The pupal period and weight were different between the sexes in each diet colony. The pupal periods in females and males showed 12.6-12.8 days and 14.1-14.5 days, respectively. The pupal weights were ca. 345 mg for females and ca. 380 mg for males. The pupation and emergence rates were ca. 91-94%, and ca. 91-95%, respectively, without significant differences between the two colonies. The pre-oviposition and oviposition periods were 3.4 days and 4.7-4.8 days, respectively. The adult longevity was 8.2 days in females and 10.3-12.4 days in males. Total offsprings produced were found to be 724-847 larvae on an average with ca. 1,400 maximum larvae. In the life table analysis, the intrinsic rates of increases (0.1181 for N4 and 0.1253 for N6) were not significantly different between the two colonies. Individual differences in the larval instar number 5 and 6 were found within a diet colony. The ratios of 5-instar larvae were ca. 22% in N4 colony and ca. 7% in N6 colony. The larval period of 6-instar larvae was longer than that of 5-instar larvae. Width of head capsule in larvae varied from ca. 309 ㎛ for 1st instar to ca. 3,065 ㎛ for 6th instar. Body lengths measured from ca. 2.0 mm for 1st instar to ca. 29.1 mm for 6th instar. Larvae of M. loreyi and M. separata were found at the same time in a maize field during June and July, 2020.

• Korean Journal of Mineralogy and Petrology
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• v.36 no.3
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• pp.167-183
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• 2023

The Janggun Pb-Zn deposit consists of Mn orebody, Pb-Zn orebody and Fe orebody. The Mn orebody composed of manganese carbonate orebody and manganese oxide orebody on the basis of their mineralogy and genesis. The geology of this deposit consists of Precambrian Weonnam formation, Yulri group, Paleozoic Jangsan formation, Dueumri formation, Janggum limestone formation, Dongsugok formation, Jaesan formation and Mesozoic Dongwhachi formation and Chungyang granite. This manganese carbonate orebody is hydrothermal replacement orebody formed by reaction of lead and zinc-bearing hydrothermal fluid and Paleozoic Janggum limestone formation. The wallrock alteration that is remarkably recognized with Pb-Zn mineralization at this hydrothermal replacement orebody consists of mainly rhodochrositization with minor of dolomitization, pyritization, sericitization and chloritization. Carbonates formed during wallrock alteration on the basis of paragenetic sequence are as followed : Ca-dolomite (Co type, wallrock) → ankerite and Ferroan ankerite (C1 type, early stage) → ankerite (C2 type) → sideroplesite (C3 type) → sideroplesite and pistomesite (C4 type, late stage). This means that Fe and Mn elements were enriched during evolution of hydrothermal fluid. Therefore, The substitution of elements during wallrock alteration beween dolomitic marble (Mg, Ca) and lead and zinc-bearing hydrothermal fluid (Fe, Mn) with paragenetic sequence is as followed : 1)Fe ↔ Mn and Mn ↔ Mg, Ca, Fe elements substitution (ankerite and Ferroan ankerite, C1 type, early stage), 2)Fe ↔ Mn, Mn ↔ Mg, Ca and Mg ↔ Ca elements substitution (ankerite, C2 type), 3)Fe ↔ Mn, Fe ↔ Ca and Mn ↔ Mg, Ca elements substitution (sideroplesite, C3 type), and 4)Fe ↔ Mg, Fe ↔ Mn and Mn ↔ Mg, Ca elements substitution (sideroplesite and pistomesite, C4 type, late stage)

• Journal of Animal Science and Technology
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• v.45 no.2
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• pp.229-240
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• 2003

An in vitro test and a broiler feeding trial were conducted to test the effect of hydrothermal treatment of wheat bran on phytate-P degradation and it’s feeding effect on performance of broilers. Hydrothermal treatment of wheat bran was carried out at 55$^{\circ}C$ with pH 5.5 buffer solution. Phytate-P content of wheat bran decreased quadrically as the wheat bran: buffer solution ratio increased from 1:0.5 to 1:5. Phytate-P degradation was not significantly affected by incubation times above 10 min., drying temperature (55$^{\circ}C$, 65$^{\circ}C$ and 75$^{\circ}C$) or pH of the buffer solution (5.5 and 7.0). A feeding trial was conducted with 240 sex separated d-old broiler chickens (Ross$^{\circledR}$). Broilers were randomly housed to 24 cages of 10 birds each. Six cages (3 of each sex) were assigned to 4 treatments: Control-normal level of non-phytate-P (NPP); LP-low NPP treatment which had 0.1% lower NPP than Control; LPWB-LP with wheat bran which provided 475 IU of plant phytase per kg diet; LPHWB-LP with hydrothermally treated wheat bran. Results of the feeding trial showed that broilers in the LP treatment gained significantly less than other treatments in starter period (1-21d) but only male broilers for growing LP gained significantly less than Control in the grower (22-35d) and overall period. There were no significant differences in weight gain among the birds of LPWB, LPHWB and Control. Feed intake during the overall period was not significantly different between LPWB and Control but that of LP was lower than LPHWB and that of LPHWB was lower than Control. Feed/gain ratio was significantly lower in LPHWB and LP than in Control and LPWP. Mortality was highest in LPHWB. Availability of crude fat, crude ash and Ca was significantly lower in LP than other treatments. Availability of P and Zn was higher in LPWB and LPHWB than in Control and LP. Availability of P, Mg and Zn was highest in LPHWP treatment. Excretion of P was significantly lower in low NPP treatments than in Control. Serum Ca level was highest whereas serum P level was lowest in LP. Tibial crude ash content was higher in wheat bran treatments, but lower in LP than Control. However, tibial Ca content was higher in Control and LP than wheat bran treatments. Tibial P content of LP and LPWB was lower than Control. However, tibial content of Fe was highest in LP. It was concluded that wheat bran, a source of plant phytase, could be used in low NPP broiler diets to prevent the depression of performance. Reduction of P excretion can be achieved concomitantly. Hydrothermal treatment of wheat bran was effective in improving utilizability of some minerals but was not effective in improving performance of broilers.

• Korean journal of applied entomology
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• v.19 no.1 s.42
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• pp.57-65
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• 1980

The oriental tobacco budmoth, Heliothis assulta Guenee were reared under various temperatures; $20^{\circ}C,\;25^{\circ}C,\;30^{\circ}C$ and the control effects of Thuricide $HP^{(R)}$ were examined. The results obtained were as fellows: 1. The adult longevity of oriental tobacco budmoth was 11.35 days, and 3.00 days for preovipositional period, 4.75 days for ovipositional Period, and 3.50 days for postovipositional period. 2. The total number of eggs laid by a female were 307 at $20^{\circ}C$, 413 at $25^{\circ}C$ and 189 at $30^{\circ}C$. The number of eggs per female per day were 64.05 in average. 3. The average egg Periods were 7.71 days at $20^{\circ}C$, 4.12 days at $25^{\circ}C$ and 3.58 days at $30^{\circ}C$ and the hatchiabilities were $71.25\%,\;78.49\%\;and\;81.05\%$ at the respective incubation temperatures. 4. The larval developmental periods were 43.51 days at $20^{\circ}C$, 21.79 days at $25^{\circ}C$ and 18.05 days at $25^{\circ}C$ and the mortalities were $80.70\%,\;95.93\%$ and $87.01\%$ at the respective temperatures. 5. The pupal developmental periods were 24.22 days at $20^{\circ}C$, 12.36 days at $25^{\circ}C$ and 11.50 days at $30^{\circ}C$ and the mortalities at the respective temperatures were $18.18\%,\;42.11\%\;and\;40.00\%$. 6. The calculated threshold temperatures for the development were $11.61^{\circ}C$ for the eggs, $11.96^{\circ}C$ for the larvae, and $10.06^{\circ}C$ for the pupae. The estimated total effective temperatures were 60.41 day degrees for e eggs, 319.35 day degrees for the larvae, 222.66 day degrees for the pupae, and overall total effective temperatures, however, would be ranged 640-660 day degrees if the reproductive period of the adult was considered. 7. The relationship between the overall developmental periods and the rearing temperature could be Y=-4.272X+155.39 (r=0.9105), where Y; number of days required to complete the life cycle, X; treated temperatures. 8. The control effects of Thuricide $HP^{(R)}$ were $73.43\%$ for spray and $58.22\%$ for bait applications.