• Analytical Science and Technology
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• v.29 no.1
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• pp.19-28
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• 2016

The objective of this study was to determine the acidification of precipitation in the Jeju area. Precipitation samples were collected from the Jeju area from 2009-2014, and the major ionic species were analyzed. In the regression analysis, through a comparison of ion balance, electric conductivity, and acid fraction, the correlation coefficients showed a good linear relationship within the range of 0.927~0.983. The volume-weighted means of the pH and electric conductivity were 4.9 and 22.7 µS/cm, respectively. The ionic strength of precipitation was 0.27±0.38 mM, indicating about 35.9 % of total precipitation within the pure precipitation criteria. The volume-weighted mean concentrations (ìeq/L) of the ionic species in the precipitation were in the order of Na⁺ > Cl⁻ > nss-SO₄²⁻ > NO₃⁻ > NH₄⁺ > Mg²⁺ > H⁺ > nss-Ca²⁺ > PO₄³⁻ > K⁺ > HCOO⁻ > CH₃COO⁻ > NO₂⁻ > F⁻ > HCO₃⁻ > CH₃SO₃⁻ . The acidification contributions by sulfuric and nitric acids were 54.5 % and 36.5 %, respectively. Meanwhile the acidification contributions by formic and acetic acids were 4.8 % and 4.2 %, respectively. Thus, it was found that the acidification of the precipitation in the Jeju area was mainly due to the inorganic acids. The neutralization factors by NH₃ and CaCO₃ were also 33 % and 20 %, respectively.

• Journal of Chest Surgery
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• v.32 no.6
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• pp.567-572
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• 1999

Background: Surgical correction of the full spectrum of esophageal atresia with tracheoesophageal fistula has improved over the years, but the mortality and morbidity assoiated with repair of these anomalies still remains high. Material and Method: We retrospectively analyzes 27 surgically treated patients with esophageal atresia and tracheoesophageal fistula at Dong-A University Hospital between January 1992 and March 1997. Result: There were 21 male and 6 female patients. Mean birth weight was 2.62$\pm$.385 kg(2.0~3.4 kg). Twenty- four(88.9%) had esophageal atresia with distal tracheoesophageal fistula, and 3(11.1%) had pure esophageal atresia. Four(14.8%) infants were allocated to Waterston risk group A, 18(66.7%) to group B, and 5(18.5%) to group C. In eighteen(66.7%) infants with associated anomalies, cardiovascular anomalies were the most common. Three had a gap length of 3.5 cm or greater(ultra-long gap) between esophageal segments, 7 had 2.0 to 3.5 cm(long gap), 8 had 1.0 to 2.0 cm(medium gap), and 9 had 1 cm or less(short gap) gap length. Among 27 neonates, 3 cases underwent staged operation, late colon interposition was done in 2, and all other 24 cases underwent primary esophageal anastomosis. Oerative mortality was 2/27(7.4%). Causes of death included acute renal failure(n=1), empyema from anastomotic leak(n=1), necrotizing enterocolitis(n=1), sepsis(n=1), insulin-dependent diabetus mellitus(n=1 . There were 4 anastomosis- related complications including stricture in 3, leakage in 1. Mortality was related to the gap length(p<.05). Conclusion: Although the complication rate associated with surgical repair of these anomalies is high, this does not always implicate the operative mortality. The overall survival can be improved by effective treatment for combined anomalies and intensive postoperatve care.

• Applied Biological Chemistry
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• v.23 no.2
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• pp.131-139
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• 1980

TOK (2,4-Dichlolo-4'-nitrodiphenyl ether) was applied to two Korean soils possessing different physico-chemical properties at a certain concentration and incubated for a certain time under flooded conditions. The metabolites and the soil microorganisms involved in the degradation of TOK are studied. Chong Ju and Chung Ju soils treated with TOK at a concentration of 500 ppm and incubated for two, four, and six months at $30^{\circ}C$ yielded 4-chloro-4'-amino diphenyl ether, 2, 4-dichloro-4'-amino diphenyl ether(amino-TOK), N-[4'-(4-chloro-phenoxy)] phenyl acetamide, and N-[4'-(4-chloro-phenoxy)] phenyl formamide as the major metabolites. TOK underwent the reduction of nitrogroup to amino group, dechlorination, acetylation, and formylation. No cleavage at the ether linkage was recognized. TOK was more readily degraded in Chung Ju soil which is characterized by the higher pH (PH 6.43), clay loam in textural class, and the higher cation exchange capacity. The toxicity of TOK as a possible environmental contaminant is expected to be considerably reduced as a result of the above degradation Twelve strains of soil bacteria were isolated from the TOK-treated Chong Ju and Chung Ju soils. As a result of the incubation of TOK in pure cultures of the isolates, T-1-1 strain isolated from Chong Ju soil had almost no degradability, whereas T-2-3 strain turned out to be the most potent. The degradation of TOK by the isolates constituted mostly the reduction of the nitro group to amino group. The citrate buffer extract of Chung Ju soil reduced TOK more readily to amino-TOK than that of Chong Ju soil.

• Economic and Environmental Geology
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• v.23 no.3
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• pp.287-308
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• 1990

The Ogmae alunite-kaolinite deposit occurs in acidic tuff, the Hwangsan Tuff, of upper Crataceous age in the Haenam volcanic field, SW Jeonnam. This deposit characterized by advanced argillic alteration formed $71.8{\pm}2.8{\sim}73.9{\pm}2.8$ Ma ago in very shallow depth environment with acid-sulfate solution. Wallrock alteration can be classified into four zones from the center to the margin of the deposit: alunite, kaolinite, illite, and silicified zone. The mineral assemblage in the alunite zone, ore zone, is alunite-quartz-pyritekaolinite. Consideration of stability relation of these minerals suggests that the maximum alteration temperature is estimated at about $250^{\circ}C$ with solution pH of 3 or below assuming that pressure does not exceed 0.3 Kb. Alunite occurs as two different types; replacement and vein-type deposit. The former one consists of fine grained alunite and the later one coarse grained and relatively pure alunite that formed by open space filling. Isomorphous substitution of Na for K in these two types of alunites range 0 to 40 %, indicating that Na/K ratio in the solution is spontaneously changed during the alteration process. Alunite which has higher Na substitution probably formed in an earlier stage while the solution sustain high Na/K ratio. K-Ar age of alunites indicate that the replacement alunite formed earlier($73.9{\pm}2.8Ma$) than the vein-type alunite($71.8{\pm}2.8Ma$). The ${\delta}^{34}S$ value of pyrite and alunite indicate that those minerals formed at isotopically nonequillibrium state. The ${\delta}^{16}O$ and ${\delta}D$ values, of kaolintics 5.0 to 9.0‰ and -54 to -99‰, respectively, indicate that those are formed by hydrothermal solution having magmatic origin which have been diluted by low ${\delta}D$ meteoric water.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.183-183
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• 2014

Recently, multiferroic materials gain much attention due to their fascinating fundamental physical properties. These materials offer wide range of potential applications such as data storage, spintronic devices and sensors, where both electronic and magnetic polarizations can be coupled. Among single-phase multiferroic materials, $BiFeO_3$ is typical because of the room-temperature magnetoelectric coupling in view of long-range magnetic- and ferroelectric-ordering temperatures. However, $BiFeO_3$ is well known to have large leakage current and small spontaneous polarization due to the existence of oxygen vacancies and other defects. Furthermore the magnetic moment of pure $BiFeO_3$ is very weak owing to its antiferromagnetic nature. Recently, various attempts have been performed to improve the multiferroic properties of $BiFeO_3$ through the co-doping at the A and the B sites, by making use of the fact that the intrinsic polarization and magnetization are associated with the lone pair of $Bi^{3+}$ ions at the A sites and the partially-filled 3d orbitals of $Fe^{3+}$ ions at the B sites, respectively. In this study, $BiFeO_3$, $Bi_{0.9}Ho_{0.1}FeO_3$, $BiFe_{0.97}Ni_{0.03}O_3$ and $Bi_{0.9}Ho_{0.1}Fe_{0.97}Ni_{0.03}O_3$ bulk compounds were prepared by solid-state reaction and rapid sintering. High-purity $Bi_2O_3$, $Ho_2O_3$, $Fe_2O_3$ and $NiO_2$ powders with the stoichiometric proportions were mixed, and calcined at $500^{\circ}C$ for 24 h to produce the samples. The samples were immediately put into an oven, which was heated up to $800^{\circ}C$ and sintered in air for 1 h. The crystalline structure of samples was investigated at room temperature by using a Rigaku Miniflex powder diffractometer. The field-dependent and temperature-dependent magnetization measurements were performed with a vibrating-sample magnetometer and superconducting quantum-interference device.

• Tuberculosis and Respiratory Diseases
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• v.40 no.6
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• pp.646-652
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• 1993

Background: Lung cancer and chronic obstructive lung disease often coexist in the same person who are elderly and cigarette smoking. There are several reports that the presence of chronic obstructive pulmonary disease constitutes an independent risk factor for the development of lung cancer. Moreover, the association between mucus hypersecrtion and lung cacer has been reported. Method: In 72 cases with primary lung cancer which were confirmed histopathologically at Chonbuk University Hospital from August 1986 to July 1991, We evaluated the relationship between spirometry and lung cancer characteristics. Results: Six cases(8.3%) showed normal lung function, 16(22.2%) cases showed pure restrictive lung disease, 46(63.9%) cases showed moderated obstructive lung disease and 4(5.6%) cases showed severe obstructive lung disease. $FEV_1$(%) was lower in central type than in peripheral type, lower in advanced non-small cell cancer and lower in subjects with phlegm. $FEV_1$/FVC(%) was higher in small cell cancer than in squamous cell cancer and higher in patients without previous pulmonary disease than with previous pulmonary disease. But there was no statistically significant difference in lung function according to histologic types and smoking history. Lung cancers with $FEV_1$/FVC less than 75% consisted of 35 cases of squamous cell cancer, 7 of small cell cancer(14%), 5 of adenocarcinoma(10%), 2 of large-cell carcinoma and 1 of unclassified carcinoma. Squamous cell carcinoma occured more in patients with $FEV_1$/FVC<75% than with $FEV_1$/FVC$\geq$75%(p<0.05). Conclusion: It was suggest that low $FEV_1$/FVC, as reflection of obstructive lung disease, may be at greater risk for squamous cell carcinoma in cigarette smoker.

• Journal of Biomedical Engineering Research
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• v.21 no.3 s.61
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• pp.273-277
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• 2000

The galvanostatic anodization of commercially Pure titanium plate (c.p.Ti, grade 2) was investigated in various concentrations of aqueous $H_3PO_4$ from 0.05M to 0.7M. The surfaces of anodic oxide films, formed by the current density in the range between 0.3 and $l.0 A/dm^2$. were analyzed by SEM and XRD. The voltage-time (V-T) curves displayed an initial linear part and a subsequent parabolic part, and the initial slopes increased with an increase in the current density in 0.05M $H_3PO_4$. As the concentration of the electrolyte increased, the V-T corves exhibit no change but the final voltage decreased. The anodic oxide film of titanium developed from fine grains to snowflake-like grains in a layered structure with an increase in the concentration of the electrolyte and current density. Sparking at the interface of the oxide/electrolyte accompanied the local deposition and dissolution of the oxide film through discharging. The crystallinity of the anodic oxide film increased with the anodizing voltage and decreased with an increase in the concentration of the electrolyte.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.799-805
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• 1998

In present paper, we examined the flayer constituents and functionality of two stage enzyme hydrolysates (TSEH) of purplish clam and oyster, and also examined reappearance of oyster flavors through repreparation of individual flayer constituents. Total free amino acid contents in TSEH was $1943.0mg\%$ for purplish clam and was $5066.2 mg\%$ for oyster, respectively, Major free amino acids in purplish clam extracts were taurine, glutamic acid, glycine, alanine, Iysine and arginine, and in oyster extracts were taurine, asparagine, glutamic acid, valine, leucine, alanine, Iysine and arginine. As for nucleotides and related compounds, AMP was the principal component though small amounts in TSEH of purplish clam and oyster, and also contents of TMAO, total creatinine, and betaine were $41.2 mg\%,\;35,9 mg\%$ and $220.9 mg\%$ for that of purplish clam and $3.51 mg\%,\;33.4 mg\%$ and $380.9 mg\%$ that of oyster, respectively. The major inorganic ions in TSEH of both samples were Na, K, P, Cl and $PO_4$, and major non-volatile organic acid was succinic acid. The TSEH of purplish clam and oyster revealed very higher inhibition effect ($84.1\%,\;77.0\%$) in ACE inhibition than that ($0\~44.7\%$) of water and autolytic extract. A synthetic oyster extract prepared from pure chemicals on the basis of the analytical data on the TSEH, satisfactorily reproduced the taste of the natural extract except for a slight lack of mildness and odor. From the omission test the major taste compounds of oyster extract were free amino acid and inorganic ions. The quaternary ammonium bases, nucleotides and related compounds seemed to net an auxiliary role in taste of that.

• Journal of Biomedical Engineering Research
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• v.19 no.1
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• pp.81-90
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• 1998

Electromagnetic waves may induce various effects on nervous tissues either by thermal or non-thermal mechanisms. This paper intoduces a method to evalute the non-thermal effect to central nervous system by measuring the EEGs of the rabbits treated by nimodipine before exposed to weak microwave field. 20 rabbits were divided into 2 groups and their EEGs were measured after their head section were exposed to 2,450 MHz microwave with the power density of 10 dBm and 20 dBm respectively for 10 minutes and compared with those of the 3rd group of 10 rabbits which were not exposed. The 4th group of 10 rabbits were intravenously given with nimodipine before exposed to 20 dBm field to determine whether this drug would reverse the EEGs changes induced by weak microwave irradiation. As field poser exceeded 20 dBm although no significant physiological changes were observed, total induced EEGs power was remarkably decreased suggesting the presence of CNS activation. Using Fourier analysis on the EEGs signal it was found that remarkable decrease in delta band and increase in the alpha and beta bands in a significant manner(P<0.05) compared to control group. The changes were, however, not reversed by nimodipine-treatment. The effects may be pure thermal in nature because no significant change has been observed in nimodipine treated rabbits.

• Korean Journal of Environmental Agriculture
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• v.16 no.1
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• pp.48-54
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• 1997

This study was performed to develop the biological treatment technology of wastewater polluted with heavy metals. The copper-tolerant bacteria, Pseudomonas stutzeri which possessed the ability to accumulate copper, was isolated from mine wastewaters polluted with various heavy metals. The characteristics of copper accumulation in the cells and the recovery of the copper from the cells accumulating zinc, were investigated. Removal rate of copper from the solution containing 100mg/l of copper by copper-tolerant bacteria was more than 78% at 2 days after inoculation with the cells. A large number of the electron-dense granules were found mainly on the cell wall and cell membrane fractions, when determined by transmission electron microscopy. Energy dispersive X-ray spectroscopy revealed that the electron-dense granules were copper complex with the substances binding copper. The copper accumulated into the cells was not desorbed by deistilled water, but more than 80% of the copper accumulated was desorbed by 0.1M-EDTA solution. The residues of the cells after combustion at $550^{\circ}C$ amounted to about 23.2% of the dry weight of the cells. EDS analysis showed that residues were relatively pure copper compound containing more than 78.4% of copper.