• Polymer(Korea)
• /
• v.26 no.4
• /
• pp.492-500
• /
• 2002

Oxidized-polyacrylonitrile (oxy-PAN) was prepared by oxidation of PAN fiber at $240^{\circ}C$, followed by base catalyzed hydrolysis reaction. The chemical structure of PAN fiber in various pH conditions was characterized by $^{13}C-NMR$ spectroscopy. The characteristic contraction and expansion behavior of oxy -PAN fiber was observed in acidic and basic medium, respectively. In basic condition, water molecules might be absorbed into the fiber with the movement of charge balancing $Na^+$ ion, on the other hand, the water molecules seemed to be expelled in acidic condition to result in contraction. It was also observed that the facile chemical modification occurred due to free diffusion of aqueous reagent into the hydrophilic PAN fiber, and the morphology was affected by pH condition.

• Journal of Welding and Joining
• /
• v.18 no.5
• /
• pp.84-89
• /
• 2000

Friction welding of titanium and aluminium is numerically modeled by the axisymmetric thermal elastic-plastic analysis. In titanium/aluminium friction welding, heat transfers into the titanium substrate to a distance of z=10(mm) on the side of the bondline and into the whole region of the aluminium substrate having the large thermal conductivity. Adjacent to the bondline, $^{\sigma}r\;and\;^{\sigma\theta}$ are tensile in the substrate whose thermal shrinkage is large, and are compressive in the substrate whose thermal shrinkage is small. $\sigma_z$ along the radial direction is large tensile at the periphery of the component. Plastic strain occurs only close to the bondline in the aluminium substrate. In the components of plastic strain, $\varepsilon^p_r\;and\;\varepsilon^p_{\theta}$ have positive values and $\varepsilon^p_r$ has large negative value. However, $\varepsilon^p_r$ is produced not because of the severity of the mechanical restraint condition, but on purpose to satisfy the condition of the volume constant. A plastic work is proposed as a measure to evaluate the mechanical severity. The plastic work is larger in the aluminium substrate than that in the titanium substrate. The mechanical condition is severer in the aluminium substrate.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1994.05a
• /
• pp.152-153
• /
• 1994

A recessed $n^{+}$-p junction diode with the serf-aligned structure is proposed and fabricated by using the polysilicon as an $n^{+}$ diffusion source. The diode structure can be applicable to the emitter-base formation of high performance bipolar device and the $n^{+}$ polysilicon emitter has an important effect on the device characteristics. The considered parameters for the polysilicon formation are the deposition condition $As^{+}$ dose for the doping of the polysilicon, and the annealing using RTP system. The vertical depth profiles of the fabricated diode are obtained by SIMS. The eleotrical characteristics are analyzed in trims of the ideality factor of diode (n), contact resistance arid reverse leakage current. The $As_{+}$ dose for the formation of good junction is current. The $As^{+}$ dose for the formation of goodjunctions is about 1∼2${\times}$$10^{16}$$cm^{-2}$ at given RTA condition ($1100^{\circ}C$, 10 sec). The $n^{+}$-p structure is successfully applied to the self-aligned bipolar device adopting a single polysilicon technology.

• Korean Journal of Optics and Photonics
• /
• v.7 no.2
• /
• pp.150-156
• /
• 1996

RWG MQW-LD has been made with our vertical LPE system from the optimal design condition for the RWG MQW-LD to be activated as weakly index-guided LD. Through several experiments we have established the growth condition which can be used through to grow the MQW-DH wafer and to control the thickness of MQW layer to ~200$\AA$. 4 ${\mu}{\textrm}{m}$-thickness of the ridge pattern has been formed through the photolithographic process on the MQW-DH wafer grown by the former condition, and then we have fabricated the RWG MQW-LD using it. From the result of measuring the electro-optical characteristics we can make sure that it can be lasing as lasing as laterally single mode at even more than $2.7I_{th}$.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.25 no.6
• /
• pp.1069-1078
• /
• 2011

The purpose of this study was to examine health promotion level and related of patients hospitalized. The participants for this study 225 of oriental medicine hospital inpatients. Health promotion, sleep, anxiety and discomfort are measured structured questionnaires each. Data were collected using structured questionnaires and analyzed using t-test, ANOVA and multiple regression. The general health promotion score is 98.12, mortality health promotion 20.31, mental health promotion 12.89, dietary health promotion 15.28, activity and rest health promotion 12.84, exercise health promotion 7.23, sleepy health promotion 15.42, seasonal health promotion 7.60 and sexual health promotion 9.31. There were significant differences in health promotion level according to spouse (p=0.003), sleep (p<0.001), anxiety (p<0.001) and discomfort (p<0.001). The significant predictors of health promotion were spouse (p<0.001), religious (p<0.001), drinking (p=0.036), sleep (p<0.001) and discomfort (p<0.001), explaining 33.7% of the variance in health promotion. Health promotion influenced not only the physical condition but also the psychological condition. The result suggest the health promotion level and predictors of health promotion is a useful index for improvement of health and prevention of disease in oriental medicine.

• Journal of Ginseng Research
• /
• v.37 no.1
• /
• pp.94-99
• /
• 2013

Proteinuric conditions demonstrate structural and compositional changes of the foot processes and slit diaphragms between podocytes. p130Cas in podocytes serves as an adapter protein anchoring glomerular basement membrane to actin filaments of podocyte cytoskeleton. To investigate the effect of ginseng total saponin (GTS) on the pathologic changes of podocyte p130Cas induced by diabetic conditions, we cultured mouse podocytes under: 1) normal glucose (5 mM, control); 2) high glucose (HG, 30 mM); 3) advanced glycosylation endproducts (AGE)-added; or 4) HG plus AGE-added conditions and treated with GTS. In confocal imaging, p130Cas colocalized with zonula occludens-1 and synaptopodin connecting to F-actin. However, diabetic conditions relocalized p130Cas molecules at perinuclear cytoplasmic area and reduced the intensity of p130Cas. In Western blotting, diabetic conditions, especially HG plus AGE-added condition, decreased cellular p130Cas protein levels at 24 and 48 h. GTS improved such quantitative and qualitative changes. These findings imply that HG and AGE have an influence on the redistribution and amount of p130Cas of podocytes, which can be reversed by GTS.

• Journal of Korea Foundry Society
• /
• v.24 no.2
• /
• pp.85-93
• /
• 2004

Mechanical property of hypereutectic Al-Si alloy is changed according to size and distribution of primary Si. Consequently, the study on the refinement for primary Si is progressed for a long time. But such effect of refinement comes out fading phenomena with the lapse of time. Therefore, this study investigated the optimum condition of primary Si refinement for hypereutectic Al-Si alloy. And we observed various primary Si size with P's fading phenomena. The experiment results were as follows. For experiment of primary Si refinement, we made hypereutectic Al-Si alloy with various amounts of P addition. As a result of experiment, we obtained the fine microstructure at 0.01wt.%P. And the optimum condition of P addition, for preventing from growth of primary Si by P fading, is estimated 0.1wt.%P.

• Microbiology and Biotechnology Letters
• /
• v.22 no.1
• /
• pp.59-64
• /
• 1994

The production and the characteristics of protease produced by Bacillus sp. SH-8 and Bacillus sp. SH-8M were investigated under the different pH conditions. Bacillus sp. SH-8 and Bacillus sp. SH-8M showed the maximum activity of protease at 60 hours(70 units/ml) AND 96 houre(50 units/ml) cultivation, respectively, under the alkaline condition(pH 10.2). However, Bacillus sp. SH-8M exhibited the maximum activities in 8 days cultivation at pH 6.9 and in 6 days cultivation at pH 7.7 Bacillus sp. SH-8M showed the protease activity at the pH change from alkaline to neutral condition, whereas Bacillus sp. SH-8 did not. In addition. all the enzymatic characteristics of protease produced by Bacillus sp. SH-8 and Bacillus sp. SH-8M were similar with the regardless of different pH conditions.

• Nuclear Engineering and Technology
• /
• v.45 no.1
• /
• pp.107-114
• /
• 2013

It is required that the pH of the sump solution should be above 7.0 to retain iodine in a liquid phase and be within the material compatibility constraints under LOCA condition of PWR. The pH of the sump solution can be determined by conventional chemical equilibrium constants or by the minimization of Gibbs free energy. The latter method developed as a computer code called SOLGASMIX-PV is more convenient than the former since various chemical components can be easily treated under LOCA conditions. In this study, SOLGASMIX-PV code was modified to accommodate the acidic and basic materials produced by radiolysis reactions and to calculate the pH of the sump solution. When the computed pH was compared with measured by the ORNL experiment to verify the reliability of the modified code, the error between two values was within 0.3 pH. Finally, two cases of calculation were performed for the SKN 3&4 and UCN 1&2. As results, pH of the sump solution for the SKN 3&4 was between 7.02 and 7.45, and for the UCN 1&2 plant between 8.07 and 9.41. Furthermore, it was found that the radiolysis reactions have insignificant effects on pH because the relative concentrations of HCl, $HNO_3$, and Cs are very low.

• Korean Journal of Soil Science and Fertilizer
• /
• v.40 no.1
• /
• pp.71-76
• /
• 2007

We investigated the effects of solution pH on swelling characteristics and relevant hydraulic conductivity of different particle sizes of Na-bentonite which have significantly high swelling capacity. The results showed that the time taken to reach the maximum swelling indexes for all pH levels ranged from 84 hours and 156 hours for pH 6.5 or above by NaOH and pH 3.5 by HCl, respectively. The maximum swelling index slightly increased with increasing particle size, while the maximum swelling indexes were less or approximately half of that of the indigenous Na-bentonite. The changes in swelling indexes before and after solution treatment were distinctive in acidic condition, especially in pH 3.5 by HCl while there were not much differences in alkali condition. For hydraulic conductivities of fully swelled Na-bentonite in a given solution pH, elution did not occur under pressure below 1 bar. But elution started as the pressure was raised to 1.5 bars or above after 500 seconds. The stabilized hydraulic conductivities observed from 1.5, 3.0, and 5.0 bars ranged from $7{\times}10^{-3}cm\;day^{-1}$ to $6{\times}10^{-3}cm\;day^{-1}$, indicating that the hydraulic conductivities were slightly higher in acidic condition than that of normal condition.