• Journal of Korean Society of Environmental Engineers
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• v.28 no.7
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• pp.704-712
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• 2006

This research was designed to investigate the removal of heavy metals, such as $Al^{3+}$, $Cu^{2+}$, $Mn^{2+}$, $Pb^{2+}$ and $Zn^{2+}$, by adsorption on clay minerals. Bentonite(Raw-Bentonite), $Ca^{2+}$ and $Na^+$ ion exchanged bentonite(Ca- and Na-Bentonite) and montmorillonite, such as KSF and K10 from Sigma Aldrich, were used as adsorbents. The component of five inorganic adsorbents was analyzed by XRF, and the concentration of metal ions was measured by ICP. The cation exchange capacity(CEC) and the particle charge of adsorbents were measured. The initial concentration range of metal ions was $10{\sim}100$ mg/L. From the experimental results, it was shown that the adsorption equilibrium was attained after $1{\sim}2$ hours. The maximum percentage removal of $Al^{3+}$, $Cu^{2+}$, $Pb^{2+}$ and $Zn^{2+}$ on Na-Bentonite were more than 98% and that of $Mn^{2+}$ was 66%. $Al^{3+}$ was leached out from KSF with the higher concentration of hydrogen ion. Percentage removals of $Pb^{2+}$ and $Zn^{2+}$ on KSF were 88% and 59%, respectively. In general, the percentage removal of metal ions was decreased with the higher initial concentration of metal ions. The adsorption capacity of metal ions on Na-Bentonite was $1.3{\sim}19$ mg/g. Freundlich equation was used to fit the acquired experimental data. As the results, the adsorption capacity of metal ions was in the order of Na-Bentonite$\gg$Raw-Bentonite$\cong$K10>Ca-Bentonite>KSF. Freundlich constant, K of Na-Bentonite was the largest for metal ions. The order K of Na-Bentonite was Al>Cu>Pb>Zn>Mn, and the adsorption intensity(1/n) was determined to be $0.2{\sim}0.39$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.2
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• pp.170-174
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• 1999

Proessing conditions for fermented and dried sauces with the underutilized fishes were investigated. Hair tail, gizzard shad, and kangdale were hydrolyzed at $60^{\circ}C$ for 6 hours using $4\%$ Alcalase, and their hydrolysates were separted by molecularporous membrane. The hydrolytic ratios of hair tail, gizzard shad, and kangdale were estimated to be $84.2\%$, $83.6\%$ and $85.1\%$, respectively. Amino nitrogen recoveries were determind to be $73.1\~73.9\%$ by a membrane with molecular weight cutoff 100 dalton and $91.7\~92.5\%$ by a membrane with 500 dalton. Ultrafiltration was very efficient means for removing bitter taste. With the additions of $2\%$ glucose, $4\%$ lactose and $4\%$ skim milk, product yields of hair tail, gizzard shad, and kangdale were determind to be $16.4\%,\;17.2\%$ and $17.0\%$, respectively. Water adsorption rates of hair tail and kangdale showed $5.0\~9.2\%$ and $5.5\~9.6\%$, respectively, under Aw 0.52$\~$0.94. Contents of total nitrogen in the fermented and dried sauces prepared with hair tail, gizzard shad and kangdale were $3.9\%,\;4.1\%$ and $3.7\%$, respectively, and those of amino nitrogen were $3.2\%,\;3.4\%$ and $3.1\%$, respectively. In the fermented and dried sauces prapared with hair tail, gizzard shad and kangdale, the hygroscopities at Aw 0.88 were $6.9\%,\;7.5\%$ and $6.8\%$, respectively, and solubilities under dissolved in water for 30 minutes were $84.6\%,\;83.6\%$ and $93.8\%$, respectively.

• Journal of Technologic Dentistry
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• v.19 no.1
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• pp.21-35
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• 1997

The Ag-Pd-Cu alloys containing a small amount of Au is commonly used for dental purposes, because this alloy is cheaper than Au-base alloys for clinical use. However, the most important characteristic of this alloy is age-hardenability, which is not exhibited by other Ag-base dental alloys. The specimens used were Ag-20Pd-20Cu ternary alloy and Au addition alloy. These alloys were melted and casted by induction electic furace and centrifugal casting machine in Ar atmoshpere. These specimens were solution treated for 2hr at $800^{\circ}C$ and were then quenched into iced water, and aged at $350{\sim}550^{\circ}C$ Age-hardening characteristics of the small Au-containing Ag-pPd-Cu dental alloys were investigated by means of hardness testing, X-ray diffraction and electron microscope observations, electrical resistance, differential scanning calorimetric, emergy dispersed spectra and electron probe microanalysis. Principal results are as follows : Hardening occured in two stages, I. e., stage I in low temperature and stage II in high temperature regions, during continuous aging. The case of hardening in stage I was due to the formation of the Llo type face centered tetragonal PdCu-ordered phase in the grain interior and hardening in stage I was affedted by the Cu concentration. In stage II, decomposition of the $\alpha$ solid solution to a PdCu ordered phase(L1o type) and an Agrich ${\alpha}2$ phase occurred and a discontiunous precipitation occurred at the grain boundary. Form the electron microscope study, it was concluded that the cause of age-hardening in this alloy is the precipitation of the PdCu ordered phase, which has AuCu I type face-centered tetragonal structure. Precipitation procedure was ${\alpha}\to{\alpha}+{\alpha}2+PdCu\to{\alpha}1+{\alpha}2+PdCu$ at Pd/Cu = 1 Ag-Pd-Cu alloy is more effective dental alloy as ageing treatment and is suitable to isothermal ageing at $450^{\circ}C$.

• Tuberculosis and Respiratory Diseases
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• v.48 no.6
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• pp.837-852
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• 2000

Backgrounds : Today, tuberculosis cannot only be cured medically, but also controlled by public health. Despite the overall worldwide decline in tuberculosis, the disease continues to be a significant problem among developing countries and in the slums of large cities in some industrialized countries. Particularly, this communicable disease has come into the public health spotlight because of its resurgence in the 1990's. our country has been operating the Korean National Tuberculosis Control Program since 1962, focusing around public health centers. Therefore, this study aims to compare the effectiveness of tuberculosis control activities, one of the major public health activities in Korea, by producing indexes, such as the yearly registration rate per 100,000 population and treatment compliance of tuberculosis on in small areas (communities). Methods : This work was accomplished by constructing a time-series analytic model using data from "1980~2000: the Yearly Statistical Report" with patient registry data of 234 City. County. District public health centers and by identifying the factors influencing the tuberculosis indexes. Results : The trends of pulmonary tuberculosis positive point prevalence and pulmonary tuberculosis negative point prevalence on X-ray screening have declined steadily, beginning in 1981 and continuing to 1998 by region (city, county, district). Although the tuberculosis mortality rate steadily shows a declining trend by year and region, but Korea still ranks first among 29 OECD countries in 1998, with a tuberculosis mortality rate of 7.1 per 100,000 persons, according to the time-series analysis for fatal diseases. Conclusion : The results of the study will form the fundamental basis of future regional health care planning and the Korean Tuberculosis Surveillance System on 2000. Since the implementation of local autonomy through the Local Health Act of 1995, it has now become vita1 for each city, county, district public health centers to determine its own priorities for relevant health care management, including budget allocation and program goals.

• Tuberculosis and Respiratory Diseases
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• v.39 no.6
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• pp.474-483
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• 1992

Background: Regardless of its causes, acute lung injury is characterized pathophysiologically by increased pulmonary arterial pressure and the protein-rich edema. Many inflammatory mediators are known to be involved in the pathogenesis of acute lung injury, including oxygen free radicals (OFR). But the changes in pulmonary capillary pressure in the OFR-induced acute lung injury is not clear. While the pulmonary edema characterized by the movement of fluid and solutes is dependent on the pressure gradient and the alveolar-capillary permeability, the role of pulmonary capillary pressure in the development of pulmonary edema is also not well understood. Method: Male Sprague-Dawley rats were divided into 5 groups: normal control (n=5), xanthine/xanthine oxidase (X/XO)-treated group (n=7), catalase-pretreated group (n=5), papaverine-pretreated group (n=7), and indomethacin-pretreated group (n=5). In isolated perfused rat lungs, the sequential changes in pulmonary arterial pressure, pulmonary capillary pressure by double occlusion method, and lung weight as a parameter of pulmonary edema were determined. Results: Pulmonary arterial pressure and pulmonary capillary pressure were increased by X/XO. This increase was significantly attenuated by catalase and papaverine, but indomethacin did not prevent the X/XO-induced increase. Lung weight gain was also observed by X/XO perfusion. It was prevented by catalase. Papaverine did not completely block the increase, but significantly delayed the onset. Indomethacin had no effect on the increase in lung weight. Conclusion: These data suggest that increased pulmonary capillary pressure by OFR may aggravate pulmonary edema in the presence of increased alveolar-capillary permeability and this may not be mediated by cyclooxygenase metabolites.

• Korean journal of food and cookery science
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• v.12 no.2
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• pp.186-192
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• 1996

Retrogradation of non-waxy rice (NWR) and waxy rice (WR) cakes (45% moisture) stored at 5$^{\circ}C$, $25^{\circ}C$ and -2$0^{\circ}C$ was studied by differential scanning calorimetry (DSC) and enzymatic ($\beta$-amylase-puuulanase) method. With DSC, endotherms did not appear with rice cakes stored at room ($25^{\circ}C$) and deep freezing (-2$0^{\circ}C$) temperatures but did with samples stored at low temperature (5$^{\circ}C$), showing accelerated retrogradation by low temperature. Onset temperature (To) and peak temperature (Tp) did not change under 14 days at 5$^{\circ}C$ but enthalpy values ($\Delta$H) increased rapidly within one day and increased steadily until 5th day of storage, then equilibrated. Higher $\Delta$H were obtained with WR cakes than NWR cakes. It was suggested that more amylopectin recrystallization occured with WR than NWR. Degrees of gelatinization of rice cakes determined by enzymatic method increased in the following order: 5$^{\circ}C$ < $25^{\circ}C$ < -2$0^{\circ}C$. In contrast with DSC results, dogrees of gelatinization of NWR cakes, were relatively lower than that of WR cakes. However, increased retrogradation extents (melting enthalpies) caused reduced enzyme susceptibilities to $\beta$-amylase-pullulanase system, among NWR or WR cakes stored at 5$^{\circ}C$. The degrees of retrogradation of rice cakes stored at 5$^{\circ}C$ were higher than those stored at $25^{\circ}C$ and -2$0^{\circ}C$ without regard to the kind of rice. The higher sensitivity of the enzymatic method was obtained than that of DSC method when the degrees of retrogradation of rice cakes were determined during storage under this experiment conditions.

• Journal of Korean Society of Forest Science
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• v.90 no.1
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• pp.64-73
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• 2001

Generally potassium in the soil can be remained as water soluble, exchangeable, and available types, respectively. Theses types of potassiums are also known to keep their kinetic relationships to each other. The Purpose on this research was to investigate types and relationships of potassium in the soil, and the characteristics of potassium supply in different forest soils. The results could be summarized as follows; 1. The amounts of available potassium in A and B horizon soils by continuous leaching with 0.01N-HCl were as follows : for A Horizon soils, pohang(Gray brown forest soils), Changsung (Brown forest soils), and Youngwol(Dark red forest soils) were ranged from 0.2me/l00g to 0.8me/100g, Taean(Red and Yellow forest soils) was 0.1-0.6me/100g, Kapyung(Brown forest soils) was 0.2-0.4me/100g. For the B layer, Youngwol was 0.1-0.5me/100g, Pohang, Taean, Kapyung were 0.1-0.4me/100g, Changsung was 0.1-0.3me/100g, respectivly. 2. Of ten times-pulse leaching with 0.01N-HCl for A layer soil, more 80% of total available potassium leaching were recovered by the second pulse as leachate for Pohang, Changsung, Youngwol, while similar amounts of potassium in the leachate were obtained with the third pulse leaching for Kapyung, Taean, respectively, On the other hand, the 80 % release of available potassium from the B layer soil was obtained by the second pulse leaching for all areas investigated. 3. For the relationships between soluble potassium and exchangeable potassium, the exchangeable potassium was increased while the soluble potassium was not changed significantly in B layer. And both soluble potassium and exchangeable potassium in A layer were similar. For the relationship between exchangeable potassium and available potassium in both A and B layers, the amounts of available potassium increased by 1.2 to 1.5 times as the exchangeable potassium increased. 4. For distribution of all types of potassium throughout locations investigated, the types of potassium were in the decreasing orders of available, exchangeable, and soluble. 5. The simplified method for an analysis of all types of potassium by sequential leaching with 0.01N-HCl should be developed not only with respect to time-saving and efficiency but also verification of the relationship between available potassium and tree growth.

• Korean Journal of Soil Science and Fertilizer
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• v.9 no.1
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• pp.33-38
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• 1976

As a basic studies for increasing food production utilizing sandy barren lands and sandy farmlands of low productivity which distributed widely in Korea, an experiment of growing rice-plant on sandy barren land was undertaken as follows. 1. Variety, IR-667 was adopted and the growing method was a nutrient-irrigation culture which aimed to minimize percolation loss in sand with an automatic contineous supplying nutrient solution for supplmenting the sand characteristics. 2. The growth type price-plant after heading was a typical higher yield plant, that is, numerous, small, narrow, and thickend leaves, straight attitute, dense fasciculated etc. though the rooting of plant after planting was delayed because of using paddy-field grown seedling. 3. The adaptability of rice-plants on sandy land seemed to be different by varieties and IR-667 was more adaptable than ordinary Japonica varieties. 4. Even at the period of heading and maturing, the root system of rice-plant grown on sand showed vigorous growth having more activated apical portions. while, even the lower leaves showed flourished state. 5. The suppling of calcium and magnecium in addition to nitrogen, phosphorus and potassium on sand made notable increase of stem number per plant, grain number per stem and yields.

• Economic and Environmental Geology
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• v.53 no.6
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• pp.667-675
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• 2020

An Alum-sludge based adsorbent (ASBA) was synthesized by the hydrothermal treatment of alum sludge obtained from settling basin in water treatment plant. ASBA was applied to remove fluoride and arsenic in artificially-contaminated aqueous solutions and mine drainage. The mineralogical crystal structure, composition, and specific surface area of ASBA were identified. The result revealed that ASBA has irregular pores and a specific surface area of 87.25 ㎡ g-1 on its surface, which is advantageous for quick and facile adsorption. The main mineral components of the adsorbent were found to be quartz(SiO2), montmorillonite((Al,Mg)2Si4O10(OH)2·4H2O) and albite(NaAlSi3O8). The effects of pH, reaction time, initial concentration, and temperature on removal of fluoride and arsenic were examined. The results of the experiments showed that, the adsorbed amount of fluoride and arsenic gradually decreased with increasing pH. Based on the results of kinetic and isotherm experiments, the maximum adsorption capacity of fluoride and arsenic were 7.6 and 5.6 mg g-1, respectively. Developed models of fluoride and arsenic were suitable for the Langmuir and Freundlich models. Moreover, As for fluoride and arsenic, the increase rate of adsorption concentration decreased after 8 and 12 hr, respectively, after the start of the reaction. Also, the thermodynamic data showed that the amount of fluoride and arsenic adsorbed onto ASBA increased with increasing temperature from 25℃ to 35℃, indicating that the adsorption was endothermic and non-spontaneous reaction. As a result of regeneration experiments, ASBA can be regenerated by 1N of NaOH. In the actual mine drainage experiment, it was found that it has relatively high removal rates of 77% and 69%. The experimental results show ASBA is effective as an adsorbent for removal fluoride and arsenic from mine drainage, which has a small flow rate and acid/neutral pH environment.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.249-254
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• 2022

With the rapid advance of the semiconductor and Information and communication technologies, remote environment monitoring technology, which can detect and analyze surrounding environmental conditions with various types of sensors and wireless communication technologies, is also drawing attention. However, since the conventional remote environmental monitoring systems require external power supplies, it causes time and space limitations on comfortable usage. In this study, we proposed the concept of the self-powered remote environmental monitoring system by supplying the power with the levitation-electromagnetic generator (L-EMG), which is rationally designed to effectively harvest biomechanical energy in consideration of the mechanical characteristics of biomechanical energy. In this regard, the proposed L-EMG is designed to effectively respond to the external vibration with the movable center magnet considering the mechanical characteristics of the biomechanical energy, such as relatively low-frequency and high amplitude of vibration. Hence the L-EMG based on the fragile force equilibrium can generate high-quality electrical energy to supply power. Additionally, the environmental detective sensor and wireless transmission module are composed of the micro control unit (MCU) to minimize the required power for electronic device operation by applying the sleep mode, resulting in the extension of operation time. Finally, in order to maximize user convenience, a mobile phone application was built to enable easy monitoring of the surrounding environment. Thus, the proposed concept not only verifies the possibility of establishing the self-powered remote environmental monitoring system using biomechanical energy but further suggests a design guideline.