• Korean Journal of Materials Research
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• v.9 no.6
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• pp.615-621
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• 1999

The new process in order to fabricate of Ni catalyst with high activity by the mechanochemical(MC) method which was combined the mechanical alloying(MA) and the chemical treatment process. The microstructure and characterization of mechanically alloyed Ni-5-wt% Al powder and Ni catalyst gained by alkali leaching were investigated byt he various analysis such as XRD, SEM-EDS, HRTEM and laser particle analyzer. The steady state powder with 1~2$\mu\textrm{m}$ mean particle size was obtained after 30hr milling with the PCA of 2 wt% stearic acid under the condition of grinding stainless steel ball to powder ratio of 60:1 and rotating speed fo 300rpm. According to result of HRTEM diffraction pattern, MA powder of the steady state was nanocrystalline $Al_3$$Ni_2$ intermetallic compound. Ni catalyst was obtained after KOH leaching of the steady state powder was about 20nm nanocrystalline which contained about 8 wt % Al.

• Korean Journal of Animal Reproduction
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• v.11 no.1
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• pp.73-84
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• 1987

This experiment was carried out to investigate the effects of hormone addition(FSH, HCG, estrogen and progesterone) and composition (BSA and FCS) of mKRB on the in vitro maturation and fertilizability of follicular oocytes of the Korean native cattle. The ovaries were removed at a slaughterhouse, returned to laboratory in a thermostat (30-35$^{\circ}C$) within 4 hr, and collected by aspirating normal follicles which had diameters of 1 to 6 mm. The oocytes with cumulus cells were cultured for 8, 16, 24 and 30 hr in a modified KRB solution containing BSA or FCS and hormones. The in vitro matured oocytes in mKRB containing FCS, FSH and steroids were transferred in the rabbit uterus for examination of their in vivo fertilizability with bovine sperm preincubated 4 to 6 hr in the rabbit uterus. 1. The mean number of oocytes collected per cattle was 6.5 from 1-3mm follicles, 1.3 from 4-6mm follicles, and total was 7.7. 2. The meiotic division at 16hr-cuture in the oocytes from 1-3mm follicles was slightly stimulated by the addition of FSH in mKRB + BSA solution compared with the control. At 30hr-culture, their maturation rates(%Met II) were also increased by FSH of 1 $\mu\textrm{g}$/ml(38.4%) and 5$\mu\textrm{g}$/ml(35.7%) as compared with the control (21.4%). The maturation rate at 30hr-culture in the oocytes from 4-6mm follicles was 53.8% and 57.1% by the FSH addition of 1$\mu\textrm{g}$/ml and 5$\mu\textrm{g}$/ml, respectively. These rates were similar with the control(57.1%), but higher than those of oocytes from 1-3mm follicles. 3. The meiotic division at 16hr-culture in the oocytes from 1-3mm follicles was stimulated by the HCG addition of 1IU/ml and 5IU/ml. However, the maturation rate at 30hr-culture was greatly decreased by the HCG addtion (26.6% and 13.3%) compared with the control(53.3%) and these rates (30.8%) in the oocytes from 4-6mm follicles were also lower than that fo the control(58.3%). 4. Low maturation rate (37.5%) of the oocytes cultured in mKRB containing BSA and 5IU/ml HCG was increased (55.0%) when 15% FCS with HCG was added to mKRB instead of BSA. 5. When 16hr-cultured oocytes in mKRB containing BSA and gonadotropins (5$\mu\textrm{g}$/ml FSH and 5IU/ml HCG) were transferred in the medium without gonadotropins and recultured for 16hr, the maturation rate of HCG-treated oocytes was greatly improved. 6. The maturation rates of oocytes were greatly affected by steroids. The combined addition of FCS+FSH+estrogen or +progesterone to mKRB increased the maturation rate compared with the combination of BSA+FSH or FCS+FSH in mKRB. 7. The fertilization rate, presence of pronuclei, was increased by the combination of FCS+FSH+p in mKRB as compared with that (5.6%) of BSA+FSH and the rates of FCS+FSH+steroids ranged from 12.5 to 17.6%.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.9
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• pp.71-80
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• 2007

This paper presents a new push-push VCO technique that extracts a second harmonic output signal from a capacitive commonnode in a negativegm oscillator topology. The generation of the $2^{nd}$ harmonics is accounted for by the nonlinear current-voltage characteristic of the emitter-base junction diode causing; 1) significant voltage clipping and 2) different rising and falling time during the switching operation of core transistors. Comparative investigations show the technique is more power efficient in the high-frequency region that a conventional push-push technique using an emitter common node. Prototype 12GHz and 17GHz MMIC VCO were realized in GaInP/GaAs HBT technology. They have shown nominal output power of -4.3dBm and -5dBm, phase noise of -108 dBc/Hz and -110.4 dBc/Hz at 1MHz offset, respectively. The phase noise results are also equivalent to a VCO figure-of-merit of -175.8 dBc/Hz and -184.3 dBc/Hz, while dissipate 25.68mW(10.7mA/2.4V) and 13.14mW(4.38mA/3.0V), respectively.

• The Journal of the Petrological Society of Korea
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• v.14 no.4 s.42
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• pp.212-225
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• 2005

This study has been designed to elucidate the morphology of Jisagae columnar joints and the petrography and petrochemistry of Daepodong basalt in Jeju Island, distributed along the 3.5 km-long coast from Seongcheonpo to Weolpyeongdong. Colonnade of the Jisagae columnar joint typically occurs within the upper part of a flow and consists of relatively well-formed basalt columns. Most columns are straight with parallel sides and diameters from 100 cm to 205 cm, $130\~139\;cm$ in maximum. Length of the columns extends up to 20 m. Most columns tend to have 6 or 5 sides but sometimes they have as few as $3\~4$ or as many as 7 or 8 sides. The Daepodong basalt consists of plagioclase, olivine, orthopyroxene, clinopyroxene, ilmenite and magnetite. Plagioclase is labradorite, clinopyroxene is augite, orthopyroxene is bronzite and olivine is chrysolite and hyalosiderite. The Daepodong basalt shows porphyritic texture with matrix of mainly intersetal texture. The Daepodong basalt is plotted into alkali rock series on the TAS diagram. The tectonic setting of the Daepodong basalt represents within plate environment.

• Economic and Environmental Geology
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• v.25 no.3
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• pp.233-243
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• 1992

Ore mineralization of the Hwanghak copper deposit in the Ogsan area occurred in three stages of quartz (stage I and II) and calcite (stage III) veining along fissures in Early Cretaceous sedimentary rocks. Ore minerals are pyrite, pyrrhotite, chalcopyrite (dominant), sphalerite, hematite, galena, and Ag-, Pb-, and Bi-sulfosalts. These were deposited during the first stage at temperatures between $370^{\circ}C$ and < $200^{\circ}C$ from fluids with salinities between 0.5 and 7.6 equiv. wt. % NaCl. There is evidence of boiling and this suggests pressures of less than 180 bars during the first stage. Equilibrium thermodynamic interpretation accompanying with mineral paragenesis and fluid inclusion data indicates that copper precipitation in the hydrothermal system occurred due to cooling and changing in chemical conditions ($fs_2$, $fo_2$, pH). Gradual temperature decrease from $350^{\circ}$ to $250^{\circ}C$ of ore fluids by boiling and mixing with less-evolved meteoric waters mainly led to copper deposition through destabilization of copper chloride complexes. Sulfur isotope values of sulfide minerals decrease systematically with paragenetic time from calculated ${\delta}^{34}S_{H_2S}$ values of 8.2 to 4.7‰. These values, together with the observed change from sulfide-only to sulfide-hematite assemblages and fluid inclusion data, suggest progressively more oxidizing conditions, with a corresponding increase of the $sulfate/H_2S$ ratio of hydrothermal fluids. Measured and calculated hydrogen and oxygen isotope valutls of ore-forming fluids suggest meteoric water dominance, approaching unexchanged meteoric water values.

• Bulletin of the Korean Chemical Society
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• v.28 no.1
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• pp.41-48
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• 2007

Large colorless single crystals of sodium zeolite X, stoichiometry |Na80 |[Si112Al80O384]-FAU, with diameters up to 200 μm and Si/Al = 1.41 have been synthesized from gels with the composition of 2.40SiO2 : 2.00NaAlO2 : 7.52NaOH : 454H2O : 5.00TEA. One of these, a colorless octahedron about 200 μm in cross-section has been treated with aqueous 0.1 M KNO3 for the preparation of K+-exchanged zeolite X. The crystal structure of |K80|[Si112Al80O384]-FAU per unit cell, a = 24.838(4) A, dehydrated at 673 K and 1 × 10-6 Torr, has been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd at 294 K. The structure was refined using all intensities to the final error indices (using only the 707 reflections for which Fo > 4σ (Fo)) R1 = 0.075 (based on F) and R2 = 0.236 (based on F2). About 80 K+ ions per unit cell are found at an unusually large number of crystallographically distinct positions, eight. Eleven K+ ions are at the centers of double 6-rings (D6Rs, site I; K-O = 2.492(6) A and O-K-O (octahedral) = 88.45(22)o and 91.55(22)o). Site-I' position (in the sodalite cavities opposite D6Rs) is occupied by five K+ ions per unit cell; these K+ ions are recessed 1.92 A into the sodalite cavities from their 3-oxygen planes (K-O = 2.820(19) A, and O-K-O = 78.6(6)o). Twety-three K+ ions are found at three nonequivalent site II (in the supercage) with occupancies of 5, 9, and 9 ions; these K+ ions are recessed 0.43 A, 0.75 A, and 1.55 A, respectively, into the supercage from the three oxygens to which it is bound (K-O = 2.36(13) A, 2.45(13) A, and 2.710(13) A, O-K-O = 116.5(20)o, 110.1(17)o, and 90.4(6)o, respectively). The remaining sixteen, thirteen, and twelve K+ ions occupy three sites III' near triple 4-rings in the supercage (K-O = 2.64(3) A, 2.94(3) A, 2.73(5) A, 2.96(6) A, 3.06(4) A, and 3.08(3) A).

• Bulletin of the Korean Chemical Society
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• v.28 no.2
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• pp.251-256
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• 2007

The crystal structure of fully dehydrated partially Cs+-exchanged zeolite X, [Cs52Na40Si100Al92O384], a = 24.9765(10) A, has been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd3 at 21 °C. The crystal was prepared by flow method for 5 days using exchange solution in which mole ratio of CsOH and CsNO3 was 1 : 1 with total concentration of 0.05 M. The crystal was then dehydrated at 400 °C and 2 × 10-6 Torr for 2 days. The structure was refined to the final error indices, R1 = 0.051 and wR2 (based on F2) = 0.094 with 247 reflections for which Fo > 4σ (Fo). In this structure, about fifty-two Cs+ ions per unit cell are located at six different crystallographic sites with special selectivity; about one Cs+ ion is located at site I, at the centers of double oxygen-rings (D6Rs), two Cs+ ions are located at site I', and six Cs+ ions are found at site II'. This is contrary to common view that Cs+ ions cannot pass sodalite cavities nor D6Rs because six-ring entrances are too small. Ring-opening by the formation of ?OH groups and ring-flexing make Cs+ ions at sites I, I', and II' enter six-oxygen rings. The defects of zeolite frameworks also give enough mobility to Cs+ ions to enter sodalite cavities and D6Rs. Another six Cs+ ions are found at site II, thirty-six are located at site III, and one is located at site III' in the supercage, respectively. Forty Na+ ions per unit cell are located at two different crystallographic sites; about fourteen are located at site I, the centers of D6Rs and twenty-six are also located at site II in the supercage. Cs+ ions and Na+ ions at site II are recessed ca. 0.34(1) A and 1.91(1) A into the supercage, respectively. In this work, the highest exchange level of Cs+ ions per unit cell was achieved in zeolite X by conventional aqueous solution methods and it was also shown that Cs+ ion could pass through the sixoxygen rings.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.08a
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• pp.55-55
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• 2020

This study investigated the growth and chlorophyll fluorescence reactions of three Ardisia genus grown under various indoor light intensity conditions with the aim of evaluating their suitability as indoor plants. Young seedlings of A. crispa (Thunb.) A.DC., A. pusilla DC., and A. japonica (Thunb.) Blume were used in the experiment. The plants were cultivated indoors for 10 weeks under different light intensities: 10, 50, 100, and 200 PPFD (μmol·m^-2·s^-1), and their growth was compared with that of plants cultivated in a greenhouse during the same period (mean value 236.8±20.4 PPFD at noon). Also, chlorophyll fluorescence analysis was investigated with a portable PAM fluorometer. The indoor plants were maintained at 12/12 h photoperiod, temperature at 25±1℃, and humidity at 55±3%. Irrigation frequency (once every three days) was the same for the indoors and the greenhouse. The results of growth in three Ardisia plants showed that almost all parameters except leaf number and chlorophyll content had similar levels regardless of light intensity. A. crispa and A. pusilla plants grown in 200 PPFD were investigated to have low chlorophyll contents. Meanwhile, chlorophyll fluorescence parameters differed based on light levels. In A. crispa, the Fv/Fm (0.77), DIo/RC (0.47) and Fm/Fo (4.77) parameters tended to be poor at 200 PPFD compared to those at other light intensities. Similarly, the DIo/RC, Fm/Fo, and Pi_Abs parameters of A. pusilla plant (200 PPFD) are 0.45, 4.48 and 2.42, respectively, which can be considered stress. The analysis of fluorescence in A. japonica showed that all parameters except ETo/RC had similar levels regardless of light intensity. The ETo/RC parameter was 0.49 and 0.72 in the control plants and plants 200 PPFD, respectively, which was lower than those in plants at other light intensities. Therefore, it seems that the relatively high light intensity acted as a stressor for Ardisia plants.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.41-41
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• 2022

제주 내 크게 6개 지역에 흩어져 분포하고 있는 곶자왈은 화산활동으로 형성되었으며 제주 산림생물자원의 46%가 분포하여 생물종다양성이 매우 높은 것으로 알려져 있다. 곶자왈은 자갈과 바위로 이루어져 있으며 토양이 적게 발달하여 건조에 직면할 가능성이 크다. 본 연구는 곶자왈에서 서식하는 멸종위기종이자 산림청에서 희귀식물로 지정한 개가시나무(Quercus gilva)와 같은 속이면서 공존하고 있는 종가시나무(Quercus glauca)의 건조 내성에 대한 반응을 알아보고자 실내에서 생리 반응을 연구하였다. 온도(22±2.94℃)와 토양 양분(10%)은 자생지의 값을 기준으로 처리하였으며 수분 처리는 토양을 채운 화분에 물이 화분 밑으로 새어나가기 직전까지 포장용수량 700mL를 공급한 후 27일간 단수하였다. 단수기간에 수분함량의 변화는 토양수분함량측정기(Watch Dog)를 설치하여 데이터를 수집하였다. 항목은 토양수분함량에 따른 광합성률, 증산률, 수분이용효율, 기공전도도, Fv/Fm, Fo, Fm, 엽록소함량을 측정하였다. 토양수분함량은 25, 27일째를 제외한 기간에 개가시나무가 종가시나무보다 높았다. 광합성률은 27일째를 제외한 기간에 개가시나무가 종가시나무보다 높았다. 증산률은 4, 5, 11, 14, 25, 27일째에 개가시나무가 종가시나무보다 낮았다. 수분이용효율은 13일째를 제외한 기간에 개가시나무가 종가시나무보다 높았다. 기공전도도는 3, 9일째에 개가시나무가 종가시나무보다 높았다. Fv/Fm은 22, 27일째를 제외한 기간에 개가시나무가 종가시나무보다 높았다. Fo은 3, 14일째를 제외한 기간에 개가시나무가 종가시나무보다 높았다. Fm과 엽록소함량은 기간에 개가시나무가 종가시나무보다 높았다. 이와 같은 실험 결과로 보았을 때 개가시나무가 종가시나무보다 건조 내성에 강한 것으로 판단된다.

• Journal of Chest Surgery
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• v.3 no.2
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• pp.73-90
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• 1970

Clinical perfusion data on 16 cases of cardiopulmonary bypass using Sigmamotor pump and RyggKyvsgaard Oxygenator which performed at Seoul National University Hospital during the period of Aug. 1968 to Aug. 1970 was analized. AIl cases were hemodiluted and the perfusion was carried out under the normothermic condition. The age of the patients ranged between 6 and 43 years. The b:dy weight varied between 18.3 and 54.0 kg and the body surface area between 0.78 and 1. 59$M^2$. The priming solution was consiste:I with fresh ACD blood. Hartmann solution and Mannitol. The average amount of priming was approximately 2242 ml. The average hemodilution rate was 17%. The flow rate ranged from 1.7L to 3.5L/Min/$M^2$ and averaged 2.4L/Min/$M^2$ or 78mI/Min/kg. The duration of perfusion varied from 22 to 110 min with average of 56.9 minutes. Some hemodynamic responses were observed. The arterial pressure dropped immediately after the initiation of partial perfusion and was more marked after the total perfusion foIlowed by gradual increase to the safety level. The central venous pressure reflected the reduced blood volume especially in the cases of prolonged perfusion which lasted over 60 min. In most of the cases, red blood cell count decreased and white blood ceIl count increased after the perfusion. Hemoglobin level was decreased, averaging of 12.5mg%, Hct 3.3% and platelets count of 18% postoperatively. Plasma hemoglobin increased mildly, from pre-perfusion average value of 4. 06mg% to postperfusion value of 22.5mg%. Serum potassium was 4.4mEq/L pre-operatively and was decreased to 3.7mEq/L postoperatively. Five cases showed definite hypopotassemia immediately after the operation. Sodium and chloride decreased mildly. These electrolyte changes are thought to be related with hemodilution. diuretics and reduced blood volume during and after the perfusion. Arterial blood pH value revealed minimal to moderate elevation from preperfusion average value of 7.376 to 7.461 during perfusion and then 7.365 after perfusion. The pC02 and hicarbonate showed minimal to moderately lowered values. The total CO2 was decreased. Buffer base decreased during perfusion (Av. 42.6mEq/L) and further decreased after the perfusion (Av. 40.8mEq/L). These arterial blood acid base changes suggested that the metabolic acidosis was accompanied by respiratory alkalosis during and immediately after the perfusion. Authors belived that the acidosis could more effectively be corrected with the more additional dose of bicarbonate than we used by this study. The chest tune drainage during the first 24 hours following operation was 1158 ml in average. One case (Case No. 15) showd definite bleeding tendency and it was believed that the cause might be due to the defect of heparin and protamine titration. The average urinary out put during 24 hours post-perfusion was 1291ml. One case (Case No. ]) showed definite post perfusion oliguria. As conclusion hemodilution using fresh ACD blood. Hartmann and Mannitol solution added with Bivon and high flow rate unler normothermia. was thought to amelioratc the severity of mctabolic acidosis during and after perfusion with relatively satisfactory effect on the diuresis and bleeding tendency.