• Geophysics and Geophysical Exploration
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• v.10 no.1
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• pp.50-59
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• 2007

The advent of towed geo-electrical array surveying on water and land has resulted in datasets of magnitude approaching that of airborne electromagnetic surveying and most suited to 1D inversion. Robustness and complete automation is essential if processing and reliable interpretation of such data is to be viable. Sharp boundaries such as river beds and the top of saline aquifers must be resolved so use of smoothness constraints must be minimised. Suitable inversion algorithms must intelligently handle low signal-to-noise ratio data if conductive basement, that attenuates signal, is not to be misrepresented. A noise-level aware inversion algorithm that operates with one elastic thickness layer per electrode configuration has been coded. The noise-level aware inversion identifies if conductive basement has attenuated signal levels so that they are below noise level, and models conductive basement where appropriate. Layers in the initial models are distributed to span the effective depths of each of the geo-electric array quadrupoles. The algorithm works optimally on data collected using geo-electric arrays with an approximately exponential distribution of quadrupole effective depths. Inversion of data from arrays with linear electrodes, used to reduce contact resistance, and capacitive-line antennae is plausible. This paper demonstrates the effectiveness of the algorithm using theoretical examples and an example from a salt interception scheme on the Murray River, Australia.

• Journal of Chest Surgery
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• v.29 no.3
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• pp.255-262
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• 1996

The donor pool for heart transplants is severely limited and there is still a legal problem of brain death. This study assessed the function of hearts "absolute anoxic" for ten minutes after asphyxia by perfusing the hearts on a Langendorfr apparatus for 45 minutes with Krebs-Henseleit buffier at 37 t at 80 cm H2O. Forty isolated rat hearts were divided into four groups. Ten control hearts (group 1) were perfused on the circuit without intervening ischemia. Ten hearts (group 2) were harvested, quickly flushed with 5cc of cold University of Wisconsin solution, and stored in the same cold solution for 4 hours. Ten hearts (group 3) were excised, quickly flushed with 5 u of cold Stanford cardioplegic solution and stored in cold saline solution for 4 hours. Ten asphyxiated hearts (group 4) had warm ischemia for ten minutes and were perfused with 5u of cold Stanford cardioplegia containing 7,500 units of urokinase to dissolve intravascular clots, and stored in cold saline solution for 1.5 hours. Time of spontaneous defibrillation (TSD) after perfusion was significantly longer in group 2, group 3 and group 4 than in group 1. TSD in group 3 and group 4 was significantly longer in comparison to that of group 2. Left ventricular developed pressure(LVDP) at 15 minutes was significantly lower in group 3 and group 4 than in group 1 and group 2. In group 4, LVDP at 30 minutes and 45 minutes was significantly lower compared with that in group 1 . In conclusion, asphyxiated rat hear;ts which had absolute anoxia for 10 minutes after as hyxia showed relatively satisfactory cardiac function. function.

• Journal of Chest Surgery
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• v.29 no.3
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• pp.331-336
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• 1996

Four operative cases of aortic valvuloplasty with leaflet extension technique using glutaraldehyde preserved tautologous pericardium are described. All patients had severe aortic regurgitation on preoperative echocardiogram, and Grade W AR on oath-angiogram. The causes of aortic regurgitation were rheumatic fever in 2 cases, degenerative change in 1 case, and 1 case of unknown cause. The autologous pericardium was fixed In a 0.625% glutaraldehyde solution for 15 minutes and rinsed in saline for an additional 15 minutes. Leaflet extension technique varied in 4 patients depending on the site and the extent of the leaflet size and lesion. There was no hospital mortality and no thromboembolic episode without anticoagulation. Post-operative cardiac size was reduced on simple chest film in all cases, and LVESD and LVEDD were reduced on folio w- up echo cardi o gram . This experience permits us to conclude that leaflet extension technique is simple and safe in valve r construction, allowing repair of aortic valves that need to be replaced.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.2
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• pp.137-144
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• 2016

The aim of this study was to evaluate the effect of a range of acidic pH values on the push-out bond strength and surface morphology of tricalcium silicate materials: Biodentine$^{(R)}$, Theracal$^{(R)}$ and ProRoot MTA$^{(R)}$. The standardized lumens of root slices prepared from extracted single-root human teeth were filled with Biodentine$^{(R)}$, Theracal$^{(R)}$ and ProRoot MTA$^{(R)}$ according to manufacturer's instructions. The specimens were randomly divided into 4 groups (n = 20) for each material and then incubated for 4 days at $37^{\circ}C$; 3 acidic groups (butyric acid buffered at pH 4.4, 5.4, 6.4) and 1 control group (phosphate buffered saline solution at pH 7.4). The push-out bond strengths were then measured by using a universal testing machine and the surface morphology of each experimental group was analyzed by a scanning electron microscope. Biodentine$^{(R)}$ and Theracal$^{(R)}$ showed higher push-out bond strength compared with ProRoot MTA$^{(R)}$ after exposure to acidic pH values. A substantial change in the surface morphology of each material occurred after exposure to different pH values. In conclusion, the push-out bond strengths of Biodentine$^{(R)}$ and Theracal$^{(R)}$ are higher than the ProRoot MTA$^{(R)}$. Further the acidic environment weakens the push-out bond strength and microstructure of tricalcium silicate materials.

• Korean Journal of Food Science and Technology
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• v.25 no.4
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• pp.327-333
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• 1993

The processing conditions and quality of sardine surimi were examined: Raw sardine meat was separated, washed in 0.2% $NaHCO_3$ and 0.15% NaCl solution, and then dewatered by centrifuge. The dewatered sardine meat was chopped, mixed with 20% emulsion curd (soybean protein : water : refined sardine oil=1:5:2.6), 4% sorbitol, 4% sucrose, 0.2% polyphosphate and 0.1% sodium erythorbate by stone mortar. The mixed sardine meat was frozen with contact freezer, packed in carton box and then stored at $-25{\pm}2^{\circ}C$. The moisture, crude protein and lipid contents of the sardine surimi product was 73.3%, 15.0% and 6.9%, respectively. Fatty acid composition of product consisted of 28.8% of saturates, 24.3% of monoenes and 47.7% of polyenes and the major fatty acids were 16:0, 20:5, 18:1, 22:6 and 16:1. The results of changes in POV, TBA value, fatty acids, texture and sensory score of products during frozen storage showed that lipid oxidation and freeze denaturation of product could be retarded, and flavor enhanced by addition 20% emulsion curd and 0.1% sodium erythorbate. In an attempt to apply sardine surimi in producing surimi-based product, it was concluded that pollack surimi could be substituted with sardine surimi up to 40% without showing any significant changes in texture and taste of surimi-based product.

• Geophysics and Geophysical Exploration
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• v.8 no.2
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• pp.156-162
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• 2005

Particularly in research related to seawater intrusion the change of fluid electrical conductivity is one of major concerns, and effective monitoring can help to optimize a water pumping performance in coastal areas. Special considerations should be given to the mounting of sensors at proper depth during the monitoring design since the vertical distribution of fluid electrical conductivity is sensitive to the characteristics of seawater intrusion zone. This tells us the multi-channel electrical conductivity monitoring is of paramount consequence. It, however, is a rare event when this approach becomes routinely available in that commonly used commercial stand-alone type sensors are very expensive and inadequate for a long term monitoring of electrical conductivity or water level due to their restricted storage and difficulty of real-time control. For this reason, we have developed a real-time monitoring system that could meet these requirements. This system is user friendly, cost-effective, and easy to control measurement parameters - sampling interval, acquisition range, and others. And this devised system has been utilized for the electrical conductivity monitoring in boreholes, Yeonggwang-gun, Korea. Monitoring has been consecutively executed for 24 hours, and the responses of electrical conductivity at some channels have been regularly increased or decreased while pumping up water. It, with well logging data implemented before/after pumping water, verifies that electrical conductivity changes in the specified depths originate from fluid movements through sand layer or permeable fractured rock. Eventually, the multi-channel electrical conductivity monitoring system makes an effective key to secure groundwater resources in coastal areas.

• 한국지구물리탐사학회:학술대회논문집
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• 2006.06a
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• pp.117-122
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• 2006

In the geophysical monitoring to understand the change of subsurface material properties with time, the time-invariant static subsurface model is commonly adopted to reconstruct a time-lapse image. This assumption of static model, however, can be invalid particularly when fluid migrates very quickly in highly permeable medium in the brine injection experiment. In such case, the resultant subsurface images may be severely distorted. In order to alleviate this problem, we develop a new least-squares inversion algorithm under the assumption that the subsurface model will change continuously in time. Instead of sampling a time-space model into numerous space models with a regular time interval, a few reference models in space domain at different times pre-selected are used to describe the subsurface structure continuously changing in time; the material property at a certain space coordinate are assumed to change linearly in time. Consequently, finding a space-time model can be simplified into obtaining several reference space models. In order to stabilize iterative inversion and to calculate meaningful subsurface images varying with time, the regularization along time axis is introduced assuming that the subsurface model will not change significantly during the data acquisition. The performance of the proposed algorithm is demonstrated by the numerical experiments using the synthetic data of crosshole dc resistivity tomography.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.3
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• pp.222-226
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• 2016

This research was carried out to investigate the germination and seedling growth characteristics of the halophyte Suaeda asparagoides under various salt concentrations, temperatures, and the presence or absence of light S. asparagoides has a non-endospermic dicotyledonous seed structure that is go stone-shaped with a dark brown color and covered by a star-shaped perianth. Germination within the temperature range $5{\sim}40^{\circ}C$ varied from 8% to 65%. The highest germination occurred at $15^{\circ}C$. In seeds exposed to salt concentrations in the range 0~400 mM, the highest germination occurred at 0 mM, and the germination progressively decreased as the salt concentration increased. When the perianth of the seed was removed, the germination increased significantly. In the presence or absence of light, germination under white light was 5~20% higher than that under darkness, which varied according to salt concentrations in the range 0~300 mM. The plant growth of S. asparagoides, evaluated by plant height, branch number, root length, fresh weight, and dry weight, was higher in the concentration range 50~100 mM, and it decreased in the other concentrations. In conclusion, the seeds of S. asparagoides showed higher germination in fresh water at low temperature of approximately $15^{\circ}C$ under light when the perianth was removed, and the plant growth was higher at salt concentrations of 50~100 mM.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.3
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• pp.25-29
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• 2014

Plasma organic thin film for PCB surface finish is a potential replacement of the conventional PCB finishes because of environment-friendly process, high corrosion-resistance and long shelf life over 1 year. In this study, solder joint properties of the plasma organic surface finish were estimated and compared with OSP surface finish. The plasma surface finish was deposited by chemical vapor deposition from fluorine-based precursors. The thickness of the plasma organic coating was 20 nm. Sn-3.0Ag-0.5Cu (SAC305) solder was used as solder joint materials. From a salt spray test, the plasma organic coating had higher corrosion resistance than the OSP surface finish. The spreadability of SAC305 on plasma organic coating was higher than that on OSP surface finish. SEM and TEM micrographs showed that the interfacial microstructure of the plasma surface finish sample were similar to that of the OSP sample. Solder joint strength of the plasma finish sample was also similar to that of the OSP finished sample.

• Journal of the Korea Concrete Institute
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• v.24 no.5
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• pp.613-621
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• 2012

Steel corrosion is one of the most critical deteriorations in concrete structures due to the problems associated with both durability and structural safety issues. For protection of steel against corrosion problems, researches to improve concrete durability and steel corrosion protection such as rebar coating by hot-dip galvanizing steel have been carried out. This study was performed to quantitatively evaluate anti-corrosion and structural performance of concrete structures reinforced with hot-dip galvanizing steel rebar. Preliminary tests for several metal coatings such as zinc, aluminum, and their alloy (Zn 45% + AL 55%) were performed. After evaluation of corrosive characteristics, Zn was selected for the coating material and the corrosion behaviors in Zn-coated steel were evaluated in various conditions. Furthermore, tensile and adhesive strengths were evaluated for the normal and the hot-dip galvanized steel. The crack patterns and structural behaviors of RC specimens with the normal and coated steel were investigated. Also, corrosion characteristics including corrosion in various coating metal and potential change in metal with notch were evaluated. Structural performances of tensile and adhesive strengths as well as RC beam behavior under flexural/shear loading were evaluated. The test and evaluation results showed that the applicability of hot-dip galvanized steel rebar can be used as corrosion resistant reinforcements for RC structures.