• Textile Coloration and Finishing
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• v.22 no.2
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• pp.132-139
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• 2010

Sericin pulverization process was applied by freezing-thawing of sericin protein concentration solution and physicochemical properties of sericin/chitosan blended films were investigated. In sericin pulverization process by freezing-thawing method, the refrigeration storage at $4^{\circ}C$ maximized gelling between sericin molecules, which increased 10% of recovery ratio from sericin concentration solution that using ultrafiltration procedure. In physicochemical properties of sericin/chitosan blended films, the maximum load of chitosan (6.7kgf) had higher than that of sericin (1.2kgf), and the elongation of sericin and chitosan had 96% and 34%, respectively. Also FT-IR analysis of sericin/chitosan blended films showed that both sericin and chitosan films had amide I peak (N-H bond) in $1,521cm^{-1}$ and amide II peak (C=O bond) in $1,630cm^{-1}$. In addition, it could confirm compatibility between both materials as indicated by the decrease in the amide I peak's absorption value as chitosan content increases.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.51-51
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• 2008

Carbon nanotubes (CNTs) have long been reported as an ideal material due to their excellent electrical conductivity and chemical and mechanical stability as well as their high aspect ratios for field emission devices. CNT emitters made by screen printing the organic binder-based CNT paste may act as a source to release gases inside a vacuum panel. These residual gases may cause a catastrophic damage by electrical arcing or ion bombardment to the vacuum microelectronic devices and may change their physical or electrical properties by adsorbing on the CNT emitter surface. In this study, we analyzed the composition of residual gases inside the vacuum-sealed panel by residual gas analyzer (RGA), investigating the effects of individual gases of different kinds at several pressures on the field emission characteristics of CNT emitters. The residual gases included $H_2$, CO, $CO_2$, $N_2$, $CH_4$, $H_2O$, $C_2H_6$, and Ar. Effect of residual gases on the field emission was studied by observing the variation of the pulse voltages with the duty ratio of3.3% to keep the constant emission current of $28{\mu}A$. Each gas species was introduced to a vacuum chamber up to three different pressures ($5\times10^{-7}$, $5\times10^{-6}$, and $5\times10^{-5}$ torr) each for 1 h while electron emission was continued. The three different pressure regions were separated by keeping a high vacuum of $\sim10^{-8}$ torr for a 1 h. The emission was terminated 6 h after the third gas exposure was completed. Field emission characteristics under residual gases will be discussed in terms of their adsorption and desorption on the surface of CNTs and the resultant change of work function.

• Childhood Kidney Diseases
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• v.18 no.1
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• pp.24-28
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• 2014

Purpose: The purpose of this study was to assess the therapeutic efficacy of methylprednisolone pulse therapy in children with IgA nephropathy and Henoch- Sch$\ddot{o}$nlein Purpura (HSP) nephritis combined with proteinuria. Methods: We retrospectively reviewed the clinical records of 21 patients who were diagnosed with IgA nephropathy and HSP nephritis based on percutaneous renal biopsy. Of the 21 patients, 15 were diagnosed with IgA nephropathy and 6 were diagnosed with HSP nephritis. They had mild to severe proteinuria at the time of diagnosis or during follow-up. Group 1 (n=7) received methylprednisolone pulse therapy three times every couple of months, and Group 2 (n=14) received oral steroid therapy. The follow-up periods for Group 1 and 2 were 14.0 (9-54) months and 26.5 (14-34) months, respectively. There was no significant difference in the follow-up duration between the two groups. Results: The average age at diagnosis and biopsy was lower in Group 1 compared to Group 2, but it was not significantly different. At admission, all patients in both groups had hematuria and 5 patients (71.4%) of Group 1 and 14 patients (100 %) of Group 2 had proteinuria. Before treatment, there was no significant difference of spot urine protein/creatinine ratio between the two groups. During followup, 7 patients of Group 1 (100%) and 10 patients of Group 2 (71.4%) showed complete improvement of proteinuria and the spot urine protein/creatinine ratio in Group 1 was significantly lower than Group 2. Conclusion: In patients with IgA nephropathy and HSP nephritis with proteinuria, methylprednisolone pulse therapy was more effective than oral steroid therapy in the reduction of proteinuria. To investigate the effects on long-term prognosis, large-scale prospective studies are needed.

• Journal of Korea Foresty Energy
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• v.19 no.2
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• pp.86-92
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• 2000

The liquefactions of $\alpha$-cellulose(Sigma Chemical, C-8002, 47H0383) was prepared in the presence of phenol using sulfuric acid as a catalyst under $N_2$ gas protection at $180^{\circ}C$ for 60minutes to examine its components. The ratio of $\alpha$-cellulose to phenol was 1: 6.2(w/w), and that to sulfuric acid was 1: 0.05(g/$m\ell$). The yields of liquefaction were calculated after the liquefied mixtures were passed through 1G4 glass filter. The luquefied product of $\alpha$-cellulose was analyzed using GC-MS Spectormeter. The 12 compounds identified by GC-MS Spectrometer, of which peak area covers 54% as 2,4-dimethyl phenol, p-isopropyl phenol, 1-ethyl-3,5-dimethyl benzene, o-isopropyl phenol, (E)-2,4\` dihydroxy-stilbene, 2,2\`-methylene-bisphenol, 4,4\`-methylenebisphenol, 3-methyl-2-hydroxyphenyl-(E)-2-hydroxyl-4\`-methoxy-stilbene, 1-phyenyl-1-(4\`hydroxyphenyl)methanol phenol derivatives. From this results, the reaction pathways of the liquefaction of cellulose were proposed through electrophilic substitution reaction. Phenol as a solvent might react with the reaction intermediates as well in the cellulose liquefaction.

• Journal of Plant Biology
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• v.38 no.4
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• pp.373-380
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• 1995

Photoinhibition of photosystem (PS) n was induced in primary leaves of 25 day-old peppers grown $100\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1},\;at\;25^{\circ}C$. The modulation of PSII functionality in vivo was induced by varying both irradiance ($0-3000\;{\mu}molm^{-2}{\cdot}s^{-1}$) and duration (0-70 min) of light treatment. The functionality of PSII was investigated in terms of photochemical efficiency of PSII (Fv/Fm) and quantum yield of $O_2$ evolution, and expressed as a function of photon exposure [$mol\;photons{\cdot}m^{-2}$, the product of irradiance and duration of light treatment (Bell and Rose, 1981)]. Contrary to the linear decline of Fv/Fm ratio showing 50% decreases by absorption of $10\;mol\;photons{\cdot}m^{-2$, quantum yield of $O_2$ evolution decreased biphasically with increasing photon exposure, showing 50% decreases by absorption of $5.5\;mol\;photons{\cdot}m^{-2}$. Treatment of low temperature at $15^{\circ}C$ for 30 min alone did not affect the functionality of PSII, but high temperature ($45^{\circ}C$) significantly inactivated PSII activity. However, when Jeaves of pepper were subjected to low or high temperature in the presence of light, PSII was substantially photoinactivated. These results suggest the presence of different photoinhibitory mechanisms at low and high temperature.rature.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.45-45
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• 2019

This experiment was carried out using artificial clay and LED in the plastic film house (irradiation time: 08:00~18:00/day). Seedlings (n = 63 per $3.3m^2$) of ginseng was planted on May 17, 2018. LED was combined with red and blue light in a 3:1 ratio and irradiated with different light intensity. The average air temperature from April to September was $12.3^{\circ}C$ $-26.0^{\circ}C$ and it was the the highest at $26.0^{\circ}C$ in August. The test area where fluorescent lamp was irradiated tended to be somewhat higher than the LED irradiation area. The chemical properties of the test soil are as follows. pH levels was 5.3~5.5, EC levels 0.45~0.52 dS/m and OM levels 33~37%. The total nitrogen content was 0.35~0.47% and the available $P_2O_5$ contents was 13.7~16.0 mg/kg, which was lower than the suitable level of 70~200 mg/kg. Exchangeable cations K and Mg contents were within acceptable ranges, but the Ca contents was $28{\sim}38cmol^+/kg$ levels higher than the permissible level ($2{\sim}6cmol^+/kg$). Germination of ginseng leaves took 8~9 days and the overall germination rate was 70~75%. The photometric characteristics of LED light intensity are as follows. The greater the light intensity, the higher the PAR (Photosynthetic Action Radiation) value, illuminance and solar irradiation. Photosynthetic rate was also increased with higher light intensity was investigated at $1.7{\sim}3.2{\mu}mol\;CO_2/m^2/s$. Leaf temperature ($23.7{\sim}24.8^{\circ}C$) by light intensity was the same trend. The growth of aerial parts (plant height etc.) were generally excellent when irradiated with 3 times the light intensity, the growth of the ginseng aerial parts were excellent as follows. The plant height was 42.6 cm, stem length was 25.2 cm, leaf length was 9.6 cm and stem diameter was 5.0 mm. The growth of underground part (root length etc.) was the same, and the root length was 24.4 cm, the tap root length was 6.0 cm, diameter of taproot was 18.2 mm and the fresh root weight was 17.2 g. There were no disease incidence such as Alternaria blight, Gray mold and Anthracnose. Disease of Damping off occurred 2.2~3.6% and incidence ratio of rusty root ginseng was 14.6~20.7%. Leaf discoloration rate was 13.7~48.9% and increased with increasing light intensity. Ginsenoside content of ginseng by light intensity is under analysis.

• Resources Recycling
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• v.30 no.6
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• pp.43-52
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• 2021

In this study, the optimal nitration process for selective lithium leaching from powder of a spent battery cell (LiNi_xCo_yMn_zO₂, LiCoO₂) was studied using Taguchi method. The nitration process is a method of selective lithium leaching that involves converting non-lithium nitric compounds into oxides via nitric acid leaching and roasting. The influence of pretreatment temperature, nitric acid concentration, amount of nitric acid, and roasting temperature were evaluated. The signal-to-noise ratio and analysis of variance of the results were determined using L₁₆(4⁴) orthogonal arrays. The findings indicated that the roasting temperature followed by the nitric acid concentration, pretreatment temperature, and amount of nitric acid used had the greatest impact on the lithium leaching ratio. Following detailed experiments, the optimal conditions were found to be 10 h of pretreatment at 700℃ with 2 ml/g of 10 M nitric acid leaching followed by 10 h of roasting at 275℃. Under these conditions, the overall recovery of lithium exceeded 80%. X-ray diffraction (XRD) analysis of the leaching residue in deionized water after roasting of lithium nitrate and other nitrate compounds was performed. This was done to determine the cause of rapid decrease in lithium leaching rate above a roasting temperature of 400℃. The results confirmed that lithium manganese oxide was formed from lithium nitrate and manganese nitrate at these temperatures, and that it did not leach in deionized water. XRD analysis was also used to confirm the recovery of pure LiNO₃ from the solution that was leached during the nitration process. This was carried out by evaporating and concentrating the leached solution through solid-liquid separation.

• Journal of Korean Society of Forest Science
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• v.89 no.3
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• pp.422-430
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• 2000

Three-year-old Pinus koraiensis seedlings, transplanted in brown forest soils originating from granite were treated with simulated acid rain of pH concentrations 5.6(control), 4.0, 3.0, 2.5 and 2.0 for 210 days from April 21 to November 17, 1999. Visible injury of the seedlings were observed at the pH 2.0 and pH 2.5 treatments. The total dry weight of the seedlings decreased at pH 2.0 treatment compared with that of the control, and T/R ratio increased at pH 2.0 treatment compared with others. The elements in each part of the seedlings, concentrations of Ca, P and content of chlorophyll in needles increased at the pH 2.0 treatment compared with the control. The concentration of N in the needles of the seedlings increased as the soil pH decreased. As the treated pH was lowered, soil pH has decreased, and concentrations of Ca, Mg, Al, and Mn increased, especially at pH 4.4. In addition, there was a strong correlation(r=0.90, p<0.05 ; r=-0.94, p<0.01) between the dry weight of the seedlings and the pH and Al concentration of the soils. Therefore, the pH and Al concentration in the soil may be useful indicator for assessing the effect of acid rain on the growth of woody plants.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.3
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• pp.210-222
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• 1983

The chemical factors of topsoil, which are associated with the prediction models of urea nitrogen (N kg/ha) need under the concept of multinutrient factor balance in soil to maintain optimum nutrient balance in rice plant grown in flooded condition, were the x/z and the Kas/Kai values. In the prediction model or equation $NRe=(58.5+0.647x/z){\cdot}F$, the F was difined as the productivity factor, which was considered to be dependent on the variety, climate and soil, and found to be better estimated as the function of Kas/Kai rather than x/z from the equation Fb=0.65+1.086kas/kai, where the x, z, Kas and Kai, respectively, were available $SiO_2$ ppm, % organic matter, K activity ratio or exchangeable $K^+/(\sqrt{Ca+Mg}+Na^+)$ in topsoil and the ideal K activity ratio determined by the equation Kai=0.03+0.00083x/z for standard variety Jinheung. The relative K activity ratio or Kas/kai in topsoil, which have to be equal to 1.0 in the prediction of K fertilizer need for standard Japonica Variety Jinheung, found to be 1.63 for the varieties of Indica ${\times}$ Japonica or Milyang No. 23 grown in Korean condition and 0.322 for the Indica varieties of IR 8, 20, 36 and 42 gown in the Philippines condition. The ideal K activity rations for different Varieties such as Indies ${\times}$ Japonica grown in Korea or $Kai_1$ and Indica grown in the Philippines or $Kai_2$ were computed to be estimated from the following equations respectively ; $\\Kai_1=0.0489+0.001353X/Z\\Kai_2=0.01+0.000267X/Z$.

• Tuberculosis and Respiratory Diseases
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• v.45 no.2
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• pp.380-387
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• 1998

Background: Minimal pressure support(PSmin) is a level of pressure support which offset the imposed work of breathing(WOBimp) developed by endotracheal tube and ventilator circuits in pressure support ventilation While the lower applied level of pressure support compared to PSmin could induce respiratory muscle fatigue, the higher level than PSmin could keep respiratory muscle rest resulting in prolongation of weaning period during weaning from mechanical ventilation PSmin has been usually applied in the level of 5~10 cm$H_2O$, but the accurate level of PSmin is difficult to be determinated in individual cases. PSmin is known to be calculated by using the equation of "PSmin = peak inspiratory flow rate during spontaneus ventilation$\times$total ventilatory system resistance", but correlation of calculated PSmin and measured PSmin has not been known. The objects of this study were firstly to assess whether customarily applied pressure support level of 5~10 cm$H_2O$ would be appropriate to offset the imposed work of breathing among the patients under weaning process, and secondly to estimate the correlation between the measured PSmin and calculated PSmin. Method : 1) Measurement of PSmin : Intratracheal pressure changes were measured through Hi-Lo jet tracheal tube (8mm in diameter, Mallinckroft, USA) by using pulmonary monitor(CP-100 pulmonary monitor, Bicore, USA), and then pressure support level of mechanical ventilator were increased until WOBimp was reached to 0.01 J/L or less. Measured PSmin was defined as the lowest pressure to make WOBimp 0.01 J/L or less. 2) Calculation of PSmin : Peak airway pressure(Ppeak), plateau airway pressure(Pplat) and mean inspiratory flow rate of the subjects were measured on volume control mode of mechanical ventilation after sedation. Spontaneous peak inspiratory flow rates were measured on CPAP mode(O cm$H_2O$). Thereafter PSmin was calculated by using the equation "PSmin = peak inspiratory flow rate$\times$R, R = (Ppeak-Pplat)/mean inspiratory flow rate during volume control mode on mechanical ventilation". Results: Sixteen patients who were considered as the candidate for weaning from mechanical ventilation were included in the study. Mean age was 64(${\pm}14$) years, and the mean of total ventilation times was 9(${\pm}4$) days. All patients except one were males. The measured PSmin of the subjects ranged 4.0~12.5cm$H_2O$ in 14 patients. The mean level of PSmin was 7.6(${\pm}2.5\;cmH_2O$) in measured PSmin, 8.6 (${\pm}3.25\;cmH_2O$) in calculated PSmin Correlation between the measured PSmin and the calculated PSmin is significantly high(n=9, r=0.88, p=0.002). The calculated PSmin show a tendancy to be higher than the corresponding measured PSmin in 8 out of 9 subjects(p=0.09). The ratio of measured PSmin/calculated PSmin was 0.81(${\pm}0.05$). Conclusion: Minimal pressure support levels were different in individual cases in the range from 4 to 12.5 cm$H_2O$. Because the equation-driven calculated PSmin showed a good correlation with measured PSmin, the application of equation-driven PSmin would be then appropriate compared with conventional application of 5~10 cm$H_2O$ in patients under difficult weaning process with pressure support ventilation.