• Journal of the Korean Electrochemical Society
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• v.22 no.3
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• pp.87-103
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• 2019

Nonaqueous organic electrolyte solution in commercially available lithium-ion batteries, due to its flammability, corrosiveness, high volatility, and thermal instability, is demanding to be substituted by safer solid electrolyte with higher cycle stability, which will be utilized effectively in large-scale power sources such as electric vehicles and energy storage system. Of various types of solid electrolytes, composite solid electrolytes with polymer matrix and active inorganic fillers are now most promising in achieving higher ionic conductivity and excellent interface contact. In this review, some kinds and brief history of solid electrolyte are at first introduced and consequent explanations of polymer solid electrolytes and inorganic solid electrolytes (including active and inactive fillers) are comprehensively carried out. Composite solid electrolytes including these polymer and inorganic materials are also described with their electrochemical properties in terms of filler shapes, such as particle (0D), fiber (1D), plane (2D), and solid body (3D). In particular, in all-solid-state lithium batteries using lithium metal anode, the interface characteristics are discussed in terms of cathode-electrolyte interface, anode-electrolyte interface, and interparticle interface. Finally, current requisites and future perspectives for the composite solid electrolytes are suggested by help of some decent reviews recently reported.

• Resources Recycling
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• v.28 no.6
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• pp.79-86
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• 2019

Recently, the use of lithium ion battery(LIB) has increased. As a result, the price of lithium and the amount spent lithium on ion battery has increased. For this reason, research on recycling lithium in waste LIBs has been conducted1). In this study, the effect of roasting for the selective lithium leaching from the spent LIBs is studied. Chemical transformation is required for selective lithium leaching in NCM LiNi_xCo_yMn_zO₂) of the spent LIBs. The carbon in the waste EV cell powder reacts with the oxygen of the oxide at high temperature. After roasting at 550 ~ 850 ℃ in the Air/N₂ atmosphere, the chemical transformation is analysed by XRD. The heat treated powders are leached at a ratio of 1:10 in D.I water for ICP analysis. As a result of XRD analysis, Li₂CO₃ peak is observed at 700 ℃. After the heat treatment at 850 ℃, a peak of Li₂O was confirmed because Li₂CO₃ is decomposed into Li₂O and CO₂ over 723 ℃. The produced Li₂O reacted with Al at high temperature to form LiAlO₂, which does not leach in D.I water, leading to a decrease in lithium leaching ratio. As a result of lithium leaching in water after heat treatment, lithium leaching ratio was the highest after heat treatment at 700 ℃. After the solid-liquid separation, over 45 % of lithium leaching was confirmed by ICP analysis. After evaporation of the leached solution, peak of Li₂CO₃ was detected by XRD.

• Magazine of the Korean Society of Agricultural Engineers
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• v.21 no.2
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• pp.28-36
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• 1979

One of most important problems in the Monsoon Asia today is the production of rice paddy to meet the needs of the ever increasing population. Diversemeans are being employed to meet this demand, both by increasing productivity of existing farm land and by bringing further areas into cultivation. The primary step in either field is to ensure that there is sufficient moisture in the soil to suit the paddy, and at the same this means that excess moisture has to be drained off the land, while in others irrigat ion has to be employed to bring sufficient water to an area. In view of the fact that the project comprises a huge amount of earthwork, it can be carried out by extensive use of construction machinery in order to shorten the period. As farm ditch has a comparatively small section with shallow cutting depth, inaddition, there is lack of access road in the field, the excavation equipment with bulldozer or tracter-shovel (backhoe) type are not applicable because there are mostly adapted for the excavation of deep and wide section. Mini-backhoe with its bucket width not larger than 0. 3m, and width of blade not larger than 1. 00m seems to be more adaptable. About 80% of excavation of ditch section will be done by the machinery while the other 20% of excavation together with the finishing of the section are supposed to be done by man-power. The embankment of ditch section can be compacted by the crawler of backhoe when it is moving along the ditch for excavation. However, Lowland paddy field in the Monsoon Asia are made particulary in rain season, therefore, heavy machinery is not easy excavation for ditch. It is very important to know exact ground support power of the working site and select machines with corresponding ground pressure. Ground support power is variable subject to quality and water content of soil and therefore selection of machines should be made duly considering ground condition of the site at the time of construction works. Farm ditches dug and compacted by mannual labar are of poor quality and subject to destruction after one or two years of operation. On the other hand, excavation and compaction by bulldozer is not practical for ditches. Backboe is suitable for slope land, but this is required cycle time of bucket excavation and dumped out. If a small-scale farm ditch trencher adaptable to lowland paddy field is invented, such a machine could greatly accelerate the massive construction work envisaged in many countries and thus significantly speed up the most difficult part of irrigation development and management in Monsoon Asia.

• Journal of Korean Public Health Nursing
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• v.9 no.1
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• pp.83-102
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• 1995

As the society is being industrialized, the fast-paced economic development that has caused substantial increase in cerebrovascular and coronary artery diseases and the industrial development and increased use of means of transportation have resulted in the rapid rise of incidents in external injuries as well. So the pubic has become acutely aware of the need for fast and effective emergency care delivery system. The goal of emergency care delivery system is to meet the emergency care needs of patients. The emergency care delivery system is seeking to efficiently satisfy the care needs of people. Therefore the purpose of this study is designed to develop an effective programs for emergency care delivery system in Korea. The following specific objectives were investigated. This emergency care delivery system must have the necessary man power, for transfering the patients, communication net work, and emergency care facilities. 1) Man power Emergency care requires n0t only specialized traning in the emergency treatment but also knowledge and experience i11 other related area, so emergency care personnel traning program should be designed in order to adapt to the specific need of emergency patients. It will be necessary to ensure professional personnel who aquires the sufficient traning and experience for emergency care and to look for legal basis. We have to develop re-educational programs for emergency nurse specialist. They should be received speciality of emergency nursing care so that they will work actively and positively in emergency part. Emergency medical doctor and nurse specialist should be given an education which is related in emergency and critical care. Emergency care personnel will continue to provide both acute and continuing care as partner with other medical team. 2) Transfering the patients. Successful management of pre-hospital care requires adequate traning for the emergency medical technician. Traning program should be required to participate in a actual first aids activites in order to have apportunities to acquire practical skills as well as theoretical knowledge. The system of emergency medical technician should be remarkablly successful with first responder firefighters. Establishing this system must add necessary ambulances operating at any given time. It will be necessary to standardize the ambulance size and equipment. Ambulance should be arranged with each and every fire station. 3) Communication net work. The head office of emergency commumication network should be arranged with the head office of fire station in community. It is proposed that Hot-line system for emergency care should be introduce. High controlled ambulance and thirtial emergency center should simultaneously equip critical-line in order to communication with each other. Ordinary ambulance and secondary emergency facility should also simultaneously equip emergency-line in order to communication with each other. 4) Emergency care facilities. Primary emergency care facilities should be covered with the ambulatory emergency patients-minor illness and injuires. Secondary emergency care facilities should be covered with the emergency admission patients. Third emergency care center should be covered with the critical patients who need special treatments and operation. Secondary and third emergency care facilities should employ emergency medical doctor and emergency nurse specialist to treat in-patients with severe and acute illness and multiple injuires. It should be fashioned for a system of emergency facilities that meets emergency patients needs. Provide incentives for increased number of emergency care facilities with traning in personal/clinical emergency care. 5) Finance It is recommended to put the finance of a emergency care on a firm basis. The emergency care delivery system should be managed by the government or accreditted organizations. In order to facilitate this relevant program the fund is needed for more efficient and effective emergency researchs, service, programs, and policy. 6) Gaining understanding and co-operation of pubic It is also important to undertake pubic education to improve understanding of first aids and C. P. R of individuals, communities and business. It is proposed that teachers and health officers be certified in C. P. R. The C. P. R education can be powerful influence save lives. Lastly appropriate emergency care information must be provided to the pubic for assisting them in choosing emergency care.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.211-217
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• 1997

The physical and chemical stability of anthocyanins from a Korean pigmented rice variety was investigated at various conditions of pH, temperature, metal ion, sugar, organic acid and light. The anthocyanin pigments were relatively stable with half-lives of 36 days (pH 2.0) and 17 days (pH 3.0), while they were decomposed in a day at neutral and basic pH of 7.0 and 9.0 at $25^{\circ}C$. The anthocyanins also showed high thermal stability at pH 3.0; the half-lives were 7.4 hr, 23.6 hr and 96.3 hr at $95^{\circ}C,\;75^{\circ}C\;and\;50^{\circ}$, respectively. Addition of di- and tri-valent metal ions at pH 3.0 resulted in the increase of color intensity and stability throughout 21 days of storage periods at $25^{\circ}C$. Most sugars added accelerated the degradation of anthocyanin pigments, so that fructose showed the greatest degradation effect on the pigments. Addition of citric acid at pH 3.0 increased stability of anthocyanins, while tartaric acid decreased stability. The anthocyanins were very sensitive on light irradiation with a degradation half-life of 14 hr under 20,000 lux-light dosage at pH 3.0.

• Bulletin of the Korean Chemical Society
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• v.30 no.6
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• pp.1285-1292
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• 2009

Large single crystals of zeolite, |$Na_{75}$|[$Si_{117}Al_{75}O_{384}$]-FAU (Na-Y, Si/Al = 1.56), were synthesized from gels with composition of 3.58Si$O_2$ : 2.08NaAl$O_2$ : 7.59NaOH : 455$H_2$O : 5.06TEA : 2.23TCl. One of these, a colorless single-crystal was ion exchanged by allowing aqueous 0.02 M CsOH to flow past the crystal at 293 K for 3 days, followed by dehydration at 673 K and 1 ${\times}\;10^{-6}$ Torr for 2 days. The crystal structure of fully dehydrated partially $Cs^+$-exchanged zeolite Y, |$Cs_{45}Na_{30}$|[$Si_{117}Al_{75}O_{384}$]-FAU per unit cell (a = 24.9080(10) $\AA$) was determined by single-crystal X-ray diffraction technique in the cubic space group Fd $\overline{3}$ m at 294(1) K. The structure was refined using all intensities to the final error indices (using only the 877 reflections with $F_o\;>\;4{\sigma}(F_o))\;R_1$ = 0.0966 (Based on F) and $R_2\;=\;0.2641\;(Based\;on\;F^2$). About forty-five $Cs^+$ ions per unit cell are found at six different crystallographic sites. The 2 $Cs^+$ ions occupied at site I, at the centers of double 6-ring (D6Rs, Cs-O = 2.774(10) $\AA$ and O-Cs-O = 88.9(3) and 91.1(3)$^o$). Two $Cs^+$ ions are found at site I’ in the sodalite cavity; the $Cs^+$ ions were recessed 2.05 $\AA$ into the sodalite cavity from their 3-oxygen plane (Cs-O = 3.05(3) $\AA$ and O-Cs-O = 77.4(13)$^o$). Site-II’ positions (opposite single 6-rings in the sodalite cage) are occupied by 7 $Cs^+$ ions, each of which extends 2.04 $\AA$ into the sodalite cage from its 3-oxygen plane (Cs-O = 3.067(11) $\AA$ and O-Cs-O = 80.1(3)$^o$). The 26 $Cs^+$ ions are nearly three-quarters filled at site II in the supercage, being recessed 2.34 $\AA$ into the supercage (Cs-O = 3.273(8) $\AA$ and O-Cs-O = 74.3(3)$^o$). The 4 $Cs^+$ ions are found at site III deep in the supercage (Cs-O = 3.321(19) and 3.08(3) $\AA$), and 4 $Cs^+$ ions at another site III’ (Cs-O = 2.87(4) and 3.38(4) $\AA$). About 30 $Na^+$ ions per unit cell are found at one crystallographic site; The $Na^+$ ions are located at site I’ in the sodalite cavity opposite double 6-rings (Na-O = 2.578(11) $\AA$ and O-Na-O = 97.8(4)$^o$).

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.2
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• pp.89-100
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• 1999

The rain water samples were collected at Chunchon and Seoul by using wet only automatic sampler from January 1996 through 1997. The daily base rain water samples collected over than 95% rainy events components, $SO_4^{-2}$, $NO_3^-$, $CI^-$, NH_4^+$, $Ca^{2+}$, $Mg^{2+}$, $Na^+$, and $K^+$, by ion chromatography. In 1996, about 77% of sampled rain water showed below pH 5.6 and the 60% of rain water was lower than pH 5.0. The volume weighted average pH was 4.7 at all sites. In 1997, the volume weighted average pH was 4.6 and 4.9 at Seoul and Chunchon, respectively. Among the rain water samples,, 87% and 55% fo samples showed below than pH 5.6 and 5.0, respectively. The pH value of Chunchon was significantly (p＜0.05) lower than Seoul at the rain samples for less than 20mm rainfall. However conductivity of the rain samples were 20.9$\mu$S/cm for 1996 and 27.7$\mu$S/cm for 1997 at Seoul, and 19.1$\mu$S/cm for 1996 and 14.1$\mu$S/cm for 1997 at Chunchon. $H_2SO_4$ and $HNO_3$ contributed 65.9% and 29.6% of free acidity at Seoul, respectively. The ratio of [$NO_3^-$]/[nss-$SO_4^{-2}$] were 0.43 at Seoul and 0.51 at Chunchon for rain samples for less than 20mm rainfall. The annual wet deposition of $CI^-$, $NO_3^-$, $SO_4^{-2}$, $H^+$M, $Na^+$, NH_4^+$, $K^+$, $Mg^{2+}$, and $Ca^{2+}$, respectively, 568.8kg/$ extrm{km}^2$, 1489.3kg/$\textrm{km}^2$, 3184.8kg/$\textrm{km}^2$, 20.9kg/$\textrm{km}^2$, 249.4kg/$\textrm{km}^2$, 1091.2kg/$\textrm{km}^2$, 189.8kg/ $\textrm{km}^2$, 90.2kg/$\textrm{km}^2$ and 702.4kg/$\textrm{km}^2$ at Seoul for 1996; 656.4kg/$\textrm{km}^2$, 2029.7kg/$\textrm{km}^2$, 3280.7kg/$\textrm{km}^2$, 27.2kg /$\textrm{km}^2$, 229.4kg/$\textrm{km}^2$, 1063.9kg/$\textrm{km}^2$, 106.9kg/$\textrm{km}^2$, 78.2kg/$\textrm{km}^2$, 645.3kg/$\textrm{km}^2$ at Seoul for 1997; 116.9kg/ $\textrm{km}^2$, 983.3kg/$\textrm{km}^2$, 1797.0kg/$\textrm{km}^2$, 21.4kg/$\textrm{km}^2$, 83.2kg/$\textrm{km}^2$, 648.1kg/$\textrm{km}^2$, 78.0kg/$\textrm{km}^2$, 22.2kg/$\textrm{km}^2$, 368.8kg/$\textrm{km}^2$ at chunchon for 1996; 100.2kg/$\textrm{km}^2$, 1077.6kg/$\textrm{km}^2$, 1754.0kg/$\textrm{km}^2$, 13.4kg/$\textrm{km}^2$, 146.0kg/$\textrm{km}^2$, 602.3kg/$\textrm{km}^2$, 88.8kg/$\textrm{km}^2$, 16.2kg/$\textrm{km}^2$ and 206.8kg/$\textrm{km}^2$ at chunchon for 1997.

• Tuberculosis and Respiratory Diseases
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• v.44 no.3
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• pp.583-591
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• 1997

The functional derangement of skeletal muscles which may be attributed to chronic hypoxia has been accepted as a possible mechanism of exercise impairment in patients with chronic obstructive pulmonary disease (COPD). The metabolic changes in skeletal muscle in patients with COPD are characterized by impaired oxidative phosphorylation, early activation of anaerobic glycolysis and excessive lactate and hydrogen ion production with exercise. But the cause of exercise limitation in patients with chronic lung disease without hypoxia has not been known. In order to evaluate the change in the skeletal muscle metabolism as a possible cause of the exercise limitation in chronic lung disease patients without hypoxia, we compared the muscular metabolic data of seven male patients which had been derived from noninvasive $^{31}P$ magnetic resonance spectroscopy(MRS) with those of five age-matched normal male control persons. $^{31}P$ MRS was studied during the sustained isometric contraction of the dominant forearm flexor muscles up to the exhaustion state and the recovery period. Maximal voluntary contraction(MVC) force of the muscle was measured before the isometric exercise, and the 30% of MVC force was constantly loaded to each patient during the isometric exercise. There were no differences of intracellular pH (pHi) and inorganic phosphate/phosphocreatine(Pi/PCr) at baseline, exhaustion state and recovery period between two groups. But pHi during the exercise was lower in patients group than the control group (p < 0.05). Pi/PCr during the exercise did not show significant difference between two groups. These results suggest that the exercise limitation in chronic lung disease patients without hypoxia also could be attributed to the abnormalities in the skeletal muscle metabolism.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.3
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• pp.203-218
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• 2011

Long-term trends and distribution patterns of water quality were investigated in the Yeoja Bay of South Sea, Korea from 1976 to 2010. Water samples were collected at 3 stations and physicochemical parameters were analyzed including water temperature, salinity, hydrogen ion concentration (pH), dissolved oxygen (DO), chemical oxygen demand (COD), suspended solids (SS) and nutrients. Spatial distribution patterns of temperature, pH and DO were not clear among stations but the seasonal variations were distinct except ammonium. The trend analysis by principal component analysis (PCA) during 31 years revealed the significant variations in water quality in the study area. Spatial water qualities were discriminated into 2 clusters by PCA; station cluster 1 and 2~3. Annual water qualities were clearly discriminated into 4 clusters by PCA. By this multi-variate analysis, the annual trends were summarized as the followings; water temperature, COD and SS tended to increase from late 1970's, decreased salinity, and increased phosphate from 1991 to 2001 and increased dissolved inorganic nitrogen. Water quality was showed by the input of fresh water same as those of Kyoungin coastal area, Asan coastal area, Choensoo bay, Gunsan coastal and Mokpo coastal area in the Yeoja Bay.

• Journal of Life Science
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• v.15 no.6 s.73
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• pp.987-993
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• 2005

A bacterium, producing a fibrinolytic enzyme, was screened from a decaying rice plant. The bacterium was identified as Bacillus subtilis by morphological, biochemical, and physiological properties and named Bacillus subtilis BK-17. The fibrinolytic enzyme (BK) was purified from supernatant of Bacillus subtilis BK-17 culture broth. The molecular weight was 31 kDa as determined by SDS-PAGE. The effect of temperature, pH, and plasminogen on the activity of the bacillokinase (BK) was analysed and the activity was compared with urokinase. The optimal temperature and pH were $50^{circ}C$ and pH 7, pH 8, respectively. The BK activity was inhibited to $45\%$, $35\%$, and $23\%$ with 1mM EDTA, $Zn^{2+}$, and $Ca^{2+}$, respectively. However, $Mg^{2+}$, $Mn^{2+}$, and $Co^{2+}$ ions did not have any significant effect on the enzyme activity The BK showed the artivity in the both plates, plasminogen-free fibrin plate and plasminogen-rich fibrin plate. The result indicates that the BK can directly act the fibrin. In comparison of fibrinolytic activity with urokinase on the fibrin plate, the BK shows about 20 folds higher activity than that of the urokinase.