• Composites Research
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• v.17 no.3
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• pp.1-7
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• 2004

In the vacuum assisted RTM (VARTM) process that has become the center of attention for manufacturing massive composite structures, a good evacuation of air in the fiber preform is recognized as the prime factor. The microvoids, or the dry spots, are formed as a result of improper gate/vent locations and the mold geometry. The non-uniform resin velocity at the flow front leads to the formation of microvoids in the fibers, whereas the air in the microvoids can migrate along with the resin flow during mold filling. The residual air in the internal voids of a composite structure may cause a degradation of the mechanical properties as well as the structural failure. In this study, a unified macro- and micro analysis methods were developed to investigate the formation and transport of air in resin during VARTM process. A numerical simulation program was developed to analyze the three-dimensional flow pattern as well as the macro- and microscopic distribution of air in a composite part fabricated by VARTM process.

• Progress in Superconductivity
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• v.13 no.1
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• pp.1-6
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• 2011

Measurement of magnetic signals generated from electric activity of myocardium provides useful information for the functional diagnosis of heart diseases. Key technical component of the magnetocardiography (MCG) technology is SQUID. To measure MCG signals with high signal-to-noise ratio, sensitive SQUID magnetic field sensors are needed. Present magnetic field sensors based on Nb SQUIDs have field sensitivity good enough to measure most of MCG signals. However, for accurate measurement of fine signal pattern or detection of local atrial fibrillation signals, we may need higher field sensitivity. In addition to field sensitivity, economic aspect of the SQUID system is also important. To simplify the SQUID readout electronics, the output voltage or flux-to-voltage transfer of SQUID should be large enough so that direct measurement of SQUID output can be done using room-temperature preamplifiers. Double relaxation oscillation SQUID (DROS), having about 10 times larger flux-to-voltage transfers than those of DC-SQUIDs, was shown to be a good choice to make the electronics compact. For effective cancellation of external noise inside a thin economic shielded room, first-order axial gradiometer with high balance, simple structure and long-baseline is needed. We developed a technology to make the axial gradiometer compact using direct bonding of superconductive wires between pickup coil and input coil. Conventional insert has mechanical support to hold the gradiometer array, and the dewar neck has equal diameter with the dewar bottom. Boiling of the liquid He can generate mechanical vibrations in the gradiometer array due to mechanical connection structure. Elimination of the mechanical support, and direct mounting of the gradiometer array into the dewar bottom can reduce the dewar neck diameter, resulting in the reduction of liquid He consumption.

• Journal of Veterinary Clinics
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• v.26 no.5
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• pp.463-466
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• 2009

A swine farm located in the Kyungpook province (designated as farm D that have been suffering from PED for several years was selected to study the etiology and the outbreak pattern of PED by clinical and laboratory examinations. Clinical examination indicated that sows exhibited signs of mastitis resulting in an inadequate transfer of lactogenic immunity against PEDV to newborn piglets. Furthermore, serological tests revealed that all sow groups and their piglets had low levels of anti-PEDV antibody. These data suggest that improper vaccination program has been indeed performed in this farm. Remarkably, despite no symptoms of PED in weaners, the presence of PEDV was identified by RT-PCR from fecal samples of weaning piglets, indicating persistent PEDV circulation in the herd. Based on these results, the following basic control schemes were executed for the control of PEDV circulation in the farm; a) A quick removal of affected pigs and disinfection of affected sheds. b) restructuring of vaccination program and employment of consultant. c) prompt treatment of mastitis and removal of poor lactogenic sows, and d) enhancement of biosecurity of farrowing house by acquisition of additional space. We evaluated risk factors and implementation of control measures in two months and were unable to found any case related to PEDV infection. Taken together, our data indicate that the method described above is effective for the control of PED outbreak in farm persistently suffering from PEDV infection.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.625-630
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• 2004

Granular media filtration is used almost universally as the last particle removal process in conventional water treatment plants. Therefore, superb particle removal efficiency is needed during this process to ensure a high quality of drinking water. However, every particle can not be removed during granular media filtration. Besides the pattern of particle attachment is different depending on physicochemical aspects of particles and suspension. Filtration experiments were performed in a laboratory-scale filter using spherical glass beads with a diameter of 0.55 mm as collectors. A single type of particle suspension (Min-U-Sil 5) and alum coagulation was used to destabilize particles. The operating conditions were similar to those of standard media filtration practice: a filtration velocity of 5 m/h. More favorable particles, i.e., particles with smaller surface charge, were well attached to the collectors especially during the early stage of filtration when zeta potential of particles and collectors are both negative. This selective attachment of the lower charged particles caused the zeta potential distribution (ZPD) of the effluent to move to a more negative range. On the other hand, the ZPDs of the effluent moved from more positive to less positive when the surface charge of particles was positive and this result was thought to be caused by ion transfer between particles and collectors.

• Archives of Reconstructive Microsurgery
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• v.11 no.2
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• pp.125-134
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• 2002

This study was designed to investigate the process of re- or neo-vascularization in the prefabricated cutaneous flap using a skeletonized arteriovenous pedicle implantation. Fourty-eight flaps were divided into six groups of eight flaps, including control group of the conventional epigastric flap. In experimental groups, skin flap was fabricated by subcutaneous implantation of a distally ligated saphenous arteriovenous pedicle in left abdomen. At 2, 4, 6, 8, and 10 weeks after, prefabricated flap was elevated as an island flap based on implanted pedicle and sutured back in place. Three days after flap repositioning, the area of flap viability was quantified, the pattern of flap vascularization was evaluated with microangiography, and the quantification of vessels was assessed histologically. There were statistically significant differences in flap viability between group 2, 3, 4, and the control (p<0.05), with increased survival area in order. But Group 5 and 6 showed higher flap viability as much as the control did. In the microangiographis study, numerous small meander vessels were newly developed in the vicinity of the implanted pedicle just only 2 weeks after pedicle implantation, but neovascularization around the tip of implanted pedicle, and its anastomosis with native vasculatures was more important for overall flap survival, which was usually developed at least 4 weeks after pedicle implantation. Histologically, vessels are evenly spread over all layers of the flap at 6 weeks after pedicle implantation. The quantification of vessels was correlated well with the improvement of flap viability (p<0.05). In conclusion, neo- and re-vascularization around the tip of implanted pedicle was an important factor for overall survival of the prefabricated flap. Therefore, skeletonized pure vascular pedicle transfer, even though it used alone without surrounding was sufficient to get higher flap viability. The optimal duration of pedicle implantation was8 weeks to obtain maximal survival.

• The Journal of Korean Physical Therapy
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• v.25 no.1
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• pp.23-28
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• 2013

Purpose: The purpose of this study was to examine the influence of a handrail (presence and position) on treadmill gait and balance in stroke patients during gait training. Methods: 39 patients with stroke (male 31, female 8) participated in this study. The training groups were classified into a no-handrail group (NHG), front handrail group (FHG), and bilateral handrail group (BHG). Each group comprised 13 subjects. The subjects were trained to walk in a straight path 30 minutes per day for 8 weeks. The Good Balance System was used to measure static balance and dynamic balance. To measure walking ability, timed up and go (TUG) was also assessed. Results: The NHG showed no significant differences in static balance, dynamic balance, and TUG. The FHG was significantly different in their medial-lateral speed of static balance, dynamic balance, and TUG. The BHG was significantly different in their static balance, dynamic balance, and TUG. Conclusion: These findings consider the effects of holding handrails concomitantly with changes in postural stability. We conclude that for training stroke patients, treadmill walking while holding handrails improves balance and gait more than treadmill walking without holding handrails. The resulting changes in muscle activity patterns may facilitate the transfer to a gait pattern. The results of this study suggest methods for training treadmill walking in stroke patients.

• Proceedings of the KSRS Conference
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• 1998.09a
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• pp.43-48
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• 1998

Prior to launch, simulated radiances of the Ocean Scanning Multispectral Imager (OSMI) will be very useful to guess the real imagery of OSMI and to check the data processing system for OSMI. The data processing system for OSMI which is one sensor of Korea Mult i - Purpose Satellite (KOMPSAT) scheduled for launch in 1999 is being developed based on the SeaWiFS Data Analysis System (SeaDAS). Such a simulation should include the spectral bands, orbital and scanning characteristics of the OSMI and KOMPSAT spacecraft. The simulation is also very helpful for finding and preparing for problem areas before launch. This paper describes a method to create simulated radiances of the OSMI over the oceans. Our method for constructing a simulated OSMI imagery is to propagate a KOMPSAT orbit over a field of Coastal Zone Color Scanner (CZCS) pigment values and to use the values and atmospheric components to calculate total radiances. A modified Brouwer - Lyddane model with drag was used for the realistic orbit prediction, the CZCS pigment data were used to compute water - leaving radiances, and a variety of radiative transfer models were used to calculate atmospheric contributions to total radiances detected by OSMI. Imagery of the simulated OSMI total radiances for 6 nominal bands was obtained. As expected, water - leaving radiances were only a small fraction of total radiances and sun glint contaminations were observed near the solar declination. Therefore, atmospheric correction is very important in the calculation of pigment concentration from total radiances. Because the imagery near the sun's glitter pattern is virtually useless and must be discarded, more advanced mission planning will be required.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.2
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• pp.261-272
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• 2013

Algae boom (Red tide) in south coastal area of Korea has been appeared several times during a decade. If algae boom appears in the desalination plant, media filter and UF filter are clogged quickly, and the plant should be shutdown. In general, Algae can be removed from water by flotation better than by sedimentation, because of the low density of algal cell. The purpose of this study conducts the CFD simulation of DAF flotation basin to apply the design of the dissolved air flotation with ball filter in the Test Bed for SWRO desalination plant. In this study, Eulerian-Eulerian multiphase model was applied to simulate the behavior of air bubbles and seawater. Density difference model and gravity were used. But de-sludge process and mass transfer between air bubbles and seawater were ignored. Main parameter is hydraulic loading rate which is varied from 20 m/hr to 27.5 m/hr. Geometry of flotation basin were changed to improve the DAF performance. According to the result of this study, the increase of hydraulic loading rate causes that the flow in the separation basin is widely affected and the concentration of air is increased. The flow pattern in the contact zone of flotation basin is greatly affected by the location of nozzle header. When the nozzle header was installed not the bottom of the contact zone but the above, the opportunity of contact between influent and recycle flow was increased.

• Analytical Science and Technology
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• v.12 no.3
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• pp.218-223
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• 1999

A single use, screen-printed sensor for the measurement of liquid phase ethanol was developed and its electrochemical performance was investigated. Disposable type edthanol sensor was fabricated by serially screen printing the carbon paste, silverd pasted and insulator inlon a polyester substrate to pattern working and reference electrode sites and electrical contact. Alcohol dehydrogenase(ADH) or alcohol oxidase(AOD) together with appropriate electron transfer mediators was immobilized on the working electrode. To improve the sensitivity and reproducibility of carbon paste electrode, some pretreatment procedures were applied and their resultant electrochemical performance was examined. The disposable type electrochemical ethanol sensor developed in this study conveniently determines the ethanol in liquid samples such as blood and in fermentation process.

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.8
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• pp.1252-1261
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• 2007

The purpose of this study was to grasp the utilization of traditional Korean Patterns used for fashion cultural products. To achieve this purpose, this study examined the range of fashion cultural products through literature review, previous researches, and market surveys and analyzed the situation of fashion cultural products and the kinds, expression methods, expression techniques, and repeat styles of utilized patterns. The analysis results are as follows. First, in the use of traditional pattern, the most frequently-used fashion cultural products were small and inexpensive accessories, followed by fashion apparel, miscellaneous goods, and living cultural goods. Second, the most frequently-used traditional patterns were plant patterns, especially flower patterns. The next frequently-used ones were mixed patterns, especially in the mixture of flower and letter patterns, and $cloisonn\'{e}$ and flower patterns. The next frequently-used traditional patterns were animal patterns(especially butterfly patterns), followed by geometric patterns, lucky omen patterns, and letter patterns. In the expression methods of used patterns, most products except handicrafts preferred simplified patterns to real patterns. Finally, in the expression techniques of traditional patterns, the most frequently used technique was traditional embroidery, followed by the use of weaving fabrics such as fine gauze and brocade which are used for Hanbok. Also, transfer dyeing which is one of printing techniques, DTP(digital textiles printing), a mixed technique which adds embroidery to weaving fabrics, hand-painting, and a gilt technique were used. The results of this study suggest that most fashion cultural products except few designers' works attached weight to some specified patterns and expression techniques regardless of the characteristics of products since there is little understanding of a variety of patterns and are few researches and development on expression techniques.