• Journal of the Korea institute for structural maintenance and inspection
• /
• v.15 no.3
• /
• pp.134-141
• /
• 2011

There have been increased economic and societal demands to continuously monitor the integrity and long-term deterioration of civil infrastructures to ensure their safety and adequate performance throughout their life span. However, it is very difficult to continuously monitor the structural condition of the pipeline structures because those are placed underground and connected each other complexly, although pipeline structures are core underground infrastructures which transport primary sources. Moreover, damage can occur at several scales from micro-cracking to buckling or loose bolts in the pipeline structures. In this study, guided wave measurement can be achieved with a self-sensing circuit using a piezoelectric active sensor. In this self sensing system, a specific frequency-induced structural wavelet response is obtained from the self-sensed guided wave measurement. To classify the multiple types of structural damage, supervised learning-based statistical pattern recognition was implemented using the damage indices extracted from the guided wave features. Different types of structural damage artificially inflicted on a pipeline system were investigated to verify the effectiveness of the proposed SHM approach.

• The Journal of the Korea Contents Association
• /
• v.15 no.11
• /
• pp.410-421
• /
• 2015

The purpose of this study is to review the contents of the legislation(2015.5.12.) for shop key money concretely and to find an effective way in making an improvement of practical protection in the process of tenant's shop key money collection. From this point of view, this study tries to make some legislative suggestions as follows. First of all, the code of conflicting definition between 'shop key money' and 'shop key money contract' in the amended Commercial Building Lease Protection Act need to be harmonized with each other because they are likely to face potential problems in the protection of tenant's shop key money collction as well as risks for confusion. In the second place, it requires to strengthen the protection of tenant's shop key money collection by approval of direct opposing power of shop key money itself on condition that it satisfies a certain prerequisites. In addition, the ambiguous codes related to the landlord's disturbance should be distinctly arranged and the distribution principle of demonstration about landlord's disturbance on tenant's shop key money collection also should be made clear. Finally, the standard level of shop key money by region, business district, and category of business should be set and announced by Ministry of Land and Transport.

• Atmosphere
• /
• v.29 no.5
• /
• pp.511-523
• /
• 2019

A new Korean Meteorological Administration (KMA) airborne measurement platform has been established for regular observations for scientific purpose over South Korea since late 2017. CRDS G-2401m analyzer mounted on the King Air 350HW was used to continuous measurement of CO₂, CH₄ and CO mole fraction. The total uncertainty of measurements was estimated to be 0.07 ppm for CO₂, 0.5 ppb for CH₄, and 4.2 ppb for CO by combination of instrument precision, repeatability test simulated in-flight condition and water vapor correction uncertainty. The airborne vertical profile measurements were performed at a regional Global Atmosphere Watch (GAW) Anmyeon-do (AMY) station that belongs to the Total Carbon Column Observing Network (TCCON) and provides concurrent observations to the Greenhouse Gases Observing Satellite (GOSAT) overpasses. The vertical profile of CO₂ shows clear altitude gradient, while the CH₄ shows non-homogenous pattern in the free troposphere over Anmyeon-do. Vertically averaged CO₂ at the altitude between 1.5 and 8.0km are lower than AMY surface background value about 7 ppm but higher than that observed in free troposphere of western pacific region about 4 ppm, respectively. CH₄ shows lower level than those from ground GAW stations, comparable with flask airborne data that was taken in the western pacific region. Furthermore, this study shows that the combination of CH₄ distribution in free troposphere and trajectory analysis, taking account of convective mixing, is a useful tool in investigating CH₄ transport processes from tropical region to Korean region in winter season.

• Journal of Pharmaceutical Investigation
• /
• v.38 no.6
• /
• pp.373-380
• /
• 2008

In order to develop optimal formulation and iontophoresis condition for the transdermal delivery of levodopa, we have evaluated the effect of two permeation enhancers, ethanol and oleic acid in microemulsion, on transdermal delivery of levodopa. In vitro flux studies were performed at $33^{\circ}C$, using side-by-side diffusion cell and full thickness hairless mouse skin. Current density applied was $0.4\;mA/cm^2$ and current was off after 6 hours application. Levodopa was analysed by HPLC at 280 nm. The o/w microemulsions of oleic acid in buffer solution (pH 2.5 & 4.5) were prepared using oleic acid, Tween 80 and ethanol. The existence of microemulsion regions were investigated in pseudo-ternary phase diagrams. Contrary to our expectation, cumulative amount of levodopa transported from microemulsion (pH 2.5) for 10 hours was similar to that from aqueous solution in all delivery methods (passive, anodal and cathodal). When pH of the micro-emulsion was pH 4.5, cumulative amount of levodopa transported for 10 hours increased about 40% (anodal) to 50% (cathodal), when compared to that from aqueous solution. Flux from pH 4.5 microemulsion showed higher value than that from pH 2.5 in all delivery methods. These results seem to indicate that electroosmosis plays more dominant role than electrorepulsion in the flux of levodopa at pH 2.5. The effect of ethanol on iontophoretic flux was studied using pH 2.5 phosphate buffer solution containing 3% or 5% (v/v) ethanol. Flux enhancement was observed in passive and anodal delivery as the concentration of the ethanol increased. Without ethanol, cathodal delivery showed higher flux than anodal delivery. Anodal delivery increased the cumulative amount of levodopa transported 1.6 fold by 5% ethanol after 10 hours. However, in cathodal delivery, no flux enhancement of levodopa was observed during current application and only marginal increase in cumulative amount transported after 10 hours was observed by 5% ethanol. These results seem to be related to the decrease in dielectric constant of the medium and the lipid extraction of the ethanol, which decrease the electroosmotic flow, and thus decrease the flux. Overall, the results provide important insights into the role of electroosmosis and electrorepulsion in the transport of levodopa through skin, and provide some useful informations for optimal formulation for levodopa.

• The Korean Journal of Physiology and Pharmacology
• /
• v.15 no.3
• /
• pp.149-156
• /
• 2011

Golgi SNAP receptor complex 1 (GS28) has been implicated in vesicular transport between intra-Golgi networks and between endoplasmic reticulum (ER) and Golgi. Additional role(s) of GS28 within cells have not been well characterized. We observed decreased expression of GS28 in rat ischemic hippocampus. In this study, we examined the role of GS28 and its molecular mechanisms in neuronal (SK-N-SH) cell death induced by hydrogen peroxide ($H_2O_2$). GS28 siRNA-transfected cells treated with $H_2O_2$ showed a significant increase in cytotoxicity under glutathione (GSH)-depleted conditions after pretreatment with buthionine sulfoximine, which corresponded to an increase of intracellular reactive oxygen species (ROS) in the cells. Pretreatment of GS28 siRNA-transfected cells with p38 chemical inhibitor significantly inhibited cytotoxicity; we also observed that p38 was activated in the cells by immunoblot analysis. We confirmed the role of p38 MAPK in cotransfected cells with GS28 siRNA and p38 siRNA in the cell viability assay, flow cytometry, and immunoblot. Involvement of apoptotic or autophagic processes in the cells was not shown in the cell viability, flow cytometry, and immunoblot analyses. However, pretreatment of the cells with necrostatin-1 completely inhibited $H_2O_2$-induced cytotoxicity, ROS generation, and p38 activation, indicating that the cell death is necroptotic. Collectively these data imply that $H_2O_2$ induces necroptotic cell death in the GS28 siRNA-transfected cells and that the necroptotic signals are mediated by sequential activations in RIP1/p38/ROS. Taken together, these results indicate that GS28 has a protective role in $H_2O_2$-induced necroptosis via inhibition of p38 MAPK in GSH-depleted neuronal cells.

• Restorative Dentistry and Endodontics
• /
• v.31 no.1
• /
• pp.50-57
• /
• 2006

The purpose of this study was to investigate influence of each file step of $ProTaper^{(R)}$ system on canal transportation. Twenty simulated canals were prepared with either engine-driven $ProTaper^{(R)}$ or manual $ProTaper^{(R)}$, Group R-resin blocks were instrumented with rotary $ProTaper^{(R)}$ and group M-resin blocks were instrumented with manual $ProTaper^{(R)}$. Pre-operative resin blocks and post-operative resin blocks after each file step preparation were scanned. Original canal image and the image after using each file step were superimposed for calculation of centering ratio The image after using each file step alld image after using previous file step were superimposed for calculation of the amount of deviation. Measurements were taken horizontally at five different levels (1 2, 3, 4 and 5 mm) from the level of apical foramen. In rotary $ProTaper^{(R)}$ instrumentation group, centering ratio and the amount of deviation of each step at all levels were not significantly different (p>0.05). In manual $ProTaper^{(R)}$ instrumentation group, centering ratio and the amount of deviation of each step at all levels except of 1 mm were not significantly different (p>0.05). At the level of 1 mn, F2 file step had significantly large centering ratio and the amount of deviation (p<0.05). Under the condition of this study, F2 file step of manual ProTaper tended to transport the apical part of the canals than that of rotary $ProTaper^{(R)}$.

• Korean Chemical Engineering Research
• /
• v.51 no.4
• /
• pp.500-505
• /
• 2013

In this study, we investigated the kinetics of gas hydrate formation in the presence of ionic liquid (IL). Hydroxyethyl-methyl-morpholinium chloride (HEMM-Cl) was chosen as a material for the promotion effect test. Phase equilibrium curve for $CH_4$ hydrate with aqueous IL solution was obtained and its induction time and consumed amount of $CH_4$ gas were also measured. Aqueous solutions containing 20~20,000 ppm of HEMM-Cl was prepared and studied at 70 bar and 274.15 K. To compare the measured results to those of the conventional promoter, sodium dodecyl sulfate was also tested at the same condition. Result showed that the hydrate equilibrium curve was shifted toward higher pressure and lower temperature region. In addition, the induction time on $CH_4$ hydrate formation in the presence of IL was not shown. The amount of consumed $CH_4$ was increased with the whole range of tested concentration of IL and the highest consumption of $CH_4$ happened at 1,000 ppm of HEMM-Cl. HEMM-Cl induced and enhanced the $CH_4$ hydrate formation with a small amount of addition. Obtained result is expected to be applied for the development of technologies such as gas storage and transport using gas hydrates.

• Journal of Advanced Marine Engineering and Technology
• /
• v.38 no.4
• /
• pp.367-375
• /
• 2014

In numbers of kinds of heat exchanger, the shell-tube heat exchanger is the most commonly used type of heat exchanger in the industry field. In order to improve the thermal performance of the heat exchanger, this study was analyzed heat transfer characteristics according to arrangement of baffle and direction of baffle and bump phase of baffle about shell-tube heat exchanger using appropriate SST (Shear Stress Transport) turbulence model for flow separation and boundary layer analysis. As the boundary condition for CFD (Computational Fluid Dynamics) analysis, the inlet temperature of shell side was constantly 344 K and the variation of the water flow rate was 6, 12, 18 and 24 l/min. As the result of analysis, zigzag baffle arrangement enhances heat transfer rate and pressure drop. Furthermore, in the direction of the baffle, heat transfer rate is more improved with vertical type and angle $45^{\circ}$ type than existing type, and pressure drop was little difference. Also, the bump shape of baffle surface contributes to heat transfer rate and pressure drop improvement due to the increased heat transfer area. Through analysis results, we knew that the increase of the heat transfer was influenced by flow separation, fluid residual time, contact area with the tube, flow rate, swirl and so on.

• Nuclear Engineering and Technology
• /
• v.17 no.4
• /
• pp.290-301
• /
• 1985

600MW(e) CANDU Primary Heat Transport System (PHTS) is composed of the two “figure-of-eight” loops and is designed to operate with the 4% Reactor Outlet Header (ROH) quality at its rated power. This existence of the two compressible regions and the positive flow-qualitly-void feedbacks are the sources of the PHTS flow instability. To ensure the PHTS stability, ROH-ROH interconnect pipes are installed as passive systems. This paper describes the investigation of the PHTS flow instability at its design full power condition. Also studied are the interconnect effect and the inherent system damping effect on the system stability. The time domain stability analyses are accessed by using the ATHER/MOD-I code which is the improved version of the KAERI developed ATHER code. Under the most adverse system modelling, the “figure-of-eight” symmetric loop shows divergent flow oscillations. Under with the interconnect, the PHTS stability is remarkably enhanced so that the system becomes stable. However, even under the conservative pressurizer modelling, the PHTS shows the more convergent flow oscillations. With the interconnect and the pressurizer modelling, its stability is highly credited. Conclusively, the inherent system damping by pressurizer itself can credit the PHTS stability without the interconnect.

• Korean Chemical Engineering Research
• /
• v.54 no.2
• /
• pp.200-205
• /
• 2016

A drug transport carrier could be used for safe send of drugs to the affected region in a human body. The chitosan is adequate for the drug delivery carrier because of adaptable to living body. The gold, a metallic nanoparticles, tends to form a nano complex at rapidly when it combined with chitosan because of its negative charge. having energy from the other, outer gold nano-complex make heat due to its property to release the contained drugs to the target area. Silver could be also formed an useful biocompatible nano-composites with chitosan which should be used as an useful drug transfer carrier because its special ability to protect microbial contamination. Being one of the oxidized nano metals, $Fe_3O_4$ is nontoxic and has been used for its magnetic characteristics. In this study, the control of catalyst, reducing agent, and solvent amount. The chitosan-$Fe_3O_4$-gold & silver nanoshell have been changed to form about 100 nm size by ionic bond between the amine group, an end group of chitosan, and the metal. It was observed the change in order to seek for its optimum reaction condition as a drug transfer carrier.