• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.2 s.25
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• pp.35-44
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• 2007

Plowable fill is generally a mixture of sand, fly ash, a small amount of cement and water. Sand is the major component of most flowable fill mixes. Marine dredged soil was adopted for flowable fill instead of fly ash. Natural sea sand and in-situ soil were used for comparison. The flow behavior, hardening characteristics, and ultimate strength behavior of flowable fill were investigated. The unconfined compression test necessary to sustain walkability as the fresh flowble fill hardens was determined and the strength at 3-days appeared to correlate well with the water-to-cement ratio. The strength parameters, like cohesion and internal friction angle, was determined along the curing time. The creep test for settlement potential was conducted. Also, potable falling weight deflectometer(PFWD) test has been carried out for elastic modulus of each controlled low strength materials(CLSM). The data presented show that marine dredged soil and in-situ soil can be successfully used in CLSM.

• Journal of Microbiology and Biotechnology
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• v.3 no.4
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• pp.217-223
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• 1993

To investigate the nature and location of the nisin-resistance determinant of Lactococcus lactis subsp. lactis 7962 (L. lactis 7962), a total plasmid DNA prepared from L. lactis 7962, a nisin producer, was used to transform L. lactis subsp. lactis LM0230, a plasmid-free and nisin-sensitive strain, by protoplast mediated transformation procedures. All of the nisin-resistant transformants acquired the ability to utilize sucrose at the same time, confirming the close linkage between these two determinants in L. lactis 7962. The plasmid DNA profiles of a few selected nisin-resistant transformants were examined by agarose gel electrophoresis. No common plasmid was found among the transformants and some small plasmids previously not present in L. lactis 7962 were detected. These transformants were named as L. lactis KL1, KL2, KL3, KL4, or KL5, respectively based on their plasmid profiles. Growth curves of all transformants were similar to that of L. lactis LM0230, but different from that of L. lactis 7962. L. lactis KL5 showed the highest level of resistance to nisin, growing up to 1, 200 IU nisin/ml after 40 hr incubation. Some nisin-sensitive derivatives of KL1 or KL2 were obtained by plasmid curing experiments. The plasmid DNA profiles of the nisin-sensitive KL1 derivatives were apparently the same as that of the KL1. All of the nisin-sensitive KL2 derivatives were plasmid-free, but a nisin-resistant strain with no apparent plasmid was also obtained. These results indicate that the nisin-resistance of the $Nis^r$ transformants is presumably mediated by the chromosomally located gene(s) rather than plasmid-encoded gene(s).

• Journal of Sensor Science and Technology
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• v.16 no.5
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• pp.325-330
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• 2007

For the application to optic devices, wafer level package including spacer with particular thickness according to optical design could be required. In these cases, the uniformity of spacer thickness is important for bonding strength and optical performance. Packaging process has to be performed at low temperature in order to prevent damage to devices fabricated before packaging. And if photosensitive material is used as spacer layer, size and shape of pattern and thickness of spacer can be easily controlled. This paper presents polymer bonding using thick, uniform and patterned spacing layer of SU-8 2100 photoresist for wafer level package. SU-8, negative photoresist, can be coated uniformly by spin coater and it is cured at $95^{\circ}C$ and bonded well near the temperature. It can be bonded to silicon well, patterned with high aspect ratio and easy to form thick layer due to its high viscosity. It is also mechanically strong, chemically resistive and thermally stable. But adhesion of SU-8 to glass is poor, and in the case of forming thick layer, SU-8 layer leans from the perpendicular due to imbalance to gravity. To solve leaning problem, the wafer rotating system was introduced. Imbalance to gravity of thick layer was cancelled out through rotating wafer during curing time. And depositing additional layer of gold onto glass could improve adhesion strength of SU-8 to glass. Conclusively, we established the coating condition for forming patterned SU-8 layer with $400{\mu}m$ of thickness and 3.25 % of uniformity through single coating. Also we improved tensile strength from hundreds kPa to maximum 9.43 MPa through depositing gold layer onto glass substrate.

• The Journal of the Korean Society for Microbiology
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• v.21 no.1
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• pp.33-45
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• 1986

On hundred and forty stains of shigella cultures isolated from the twelve hygiene laboratories of cities and provincial general hospital laboratories in 1983 were tested for their resistance to thirteen antimicrobial drugs and their R-plasmid transfer. Antimicrobial drugs were used amikacin, ampicillin, cephalothin, chloramphenicol, gentamicin, kanamycin, nalidixic acid, rifampicin, streptamycin, tetracycline, tobramycin, cefoperazone and piperacillin. All strains were resistant to one or more of thirteen antimicrobial drugs but 94.3% were susceptible to amikacin, gentamicin and tobramycin of total isolated. The most strains commonly found resistance was to chloramphenicol (94%) followed by streptamycin (93%), tetracyline (92%) piperacillin (90%) ampicillin (83%), cefoperazone (42%), nalidixic acid (14%), cephalothin (17%), rifampicin (22%) and kanamycin (6%), sixty percent of strains among 140 were resistance to ampicillin, chloramphenicol, streptomycin, tetracycline at the same time. The transfer of drug resistance by conjugation was tested and ninety four strains (94.3%) were resistant to one or more drugs were found to transfer their drug resistance of E. coli. percentage of transfer frequency by conjugation was one strains (54%), the transfer frequency of drug resistance varied by donor strains and recipients, but not by selecting drugs. Resistance to nalidixic acid was not transferred by conjugation to recipients. Percentage of plasmid curing after the treatment of acriflavine, acridine orange was about 8%. Among strains cured two strains were tested compare original strains with them in biochemical properties in arginine dihydrolase and arabinose fermentation reaction. It was found to growth curves of No.2 shigella flexneri, serotype 1b, and its derivatives cured with acriflavine in $M{\ddot{u}}ller$ Hinton broth medium (pH 7.4, $38^{\circ}C$) by temperature Gradient Biophoto Recorder TN-1120 (Tokyo, Japan).

• Food Science and Biotechnology
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• v.14 no.5
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• pp.634-638
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• 2005

The effects of ingredients added (first cutting ingredients vs. both first and second cutting ingredients), and cooking method (smoking vs. boiling) on product quality and volatile compounds were examined for low-fat and regular-fat sausages. Regular-fat sausages had slightly higher pH values (6.2-6.3) than those (6.1-6.2) of low-fat counterparts. However, the pH values of the sausages were not significantly affected by the different ingredients and cooking methods (p>0.05). Approximately 30 volatile compounds were identified from these comminuted sausages. The headspace concentrations of 4-methyl-1-[1-methylethyl]-3-cyclohexen-1-ol, ${\alpha}$- terpenyl acetate, eugenol, trans-caryophyllene and myristicine were lower in low-fat and regular-fat sausages containing the first cutting ingredients alone, than in those with both cutting ingredients. The volatile compounds of the smoked comminuted sausages were mostly phenols and hetero-compounds, and a lot of volatile compounds were shown before the retention time (RT) of 30 min. However, not many volatile compounds were detected in the boiled sausages prior to the RT of 30 min.

• International Journal of Highway Engineering
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• v.15 no.2
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• pp.113-119
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• 2013

PURPOSES : The objectives of this study are to develop the eco-friendly pavement material using polyurethane binder and evaluate mechanical properties of the developed binder and concrete. METHODS : The bending beam test was conducted to select the sample candidates of polyurethane binder based on the bending strength. The characteristics of viscosity, curing time, and temperature change of sample binder was examined on different temperature conditions. The mechanical properties of polyurethane binder was estimated using the dynamic modulus testing. The indirect tensile strength test was conducted on polyurethane binder concrete with different gradation and binder content for evaluating the mechanical properties of concretes. RESULTS : Based on the beading beam test, four different binder samples were prepared for estimate the mechanical properties. The viscosity of polyurethane binder tends to increase with increase of liquid temperature and the hardening phenomenon begins 10 to 15 minutes at room temperature after mixing the resin and hardener. It is observed that the dynamic modulus of binder increases as loading frequency increases and change of modulus is found to be the highest in the PU-2I binder type. The PU-2I binder concretes shows the largest value of indirect tensile strength and indirect tensile energy. CONCLUSIONS : The use of polyurethane binder as pavement materials is capable of increasing the pavement performance and reducing the detrimental environmental effect during the highway construction.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.2
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• pp.353-361
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• 2007

This study searched the medical thought of Cheon Sun Eui (全循義). The relavance of his writings with the modern Korean Traditional Medicine, the science of food and nutrition, and the living science. His medical philosophy which was expressed in SikRyoChanYo(食療贊要), SanGaYoGok(山家要錄), ChimGuTaeKIlPeonJip(鍼灸澤日編集), etc., was investigated. The purpose of SikRyoChanYo(食療贊要) was to describe the food therapeutics before using drugs for treatment of diseases and stress the prevention of illness using foods. Second, he mentioned the science of breeding of plants and the method of food storage in his writing, SanGaYoGok(山家要錄). In this writings, the method of preparing and processing foods, storage of foods, fermentation of foods, the science of breeding of plants, etc., was mentioned. So, he could be called as a scientist. Also, he stressed the importance of food in maintaining health and curing illness in this book. Third, he wrote the good and bad luck of time and the day of getting away from the bad luck when the acupuncture and moxibustion was performed. In ChimGuTaeKIlPeonJip(鍼灸澤日編集), he reflected together the energy changes of nature and body in performing therapeutics.

• Journal of the Korean Society of Food Culture
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• v.18 no.1
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• pp.1-8
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• 2003

Recently, the concern about safety and functional substances of foods are increased therefore antioxidant substances and plants which had pharmacological effect have been studied actively. It has been known that the mulberry leaf is effective in curing many diseases. Nowaday, the pharmachological effects of mulberry leaves on diabetes mellitus and their usage for many aspects were confirmed. Mulberry leaves are known for effective in prevention of diabetes mellitus, because of specific amino acids and fibers. In this study, methanol, hexane, chlorform, ethyl acetate, and butanol extracts obtained from mulberry leaves were added to soybean oil and they were stored for 30 days at $60{\pm}2^{\circ}C$ and peroxide value(POV) and conjugated diene value(CDV) were measured periodically. Results of this study were obtained as follows; 1. The POV of soybean oil after the addition of each mulberry leaves powder(MLP) extracts generally enhanced as the storage time was prolonged, so the POV of all samples was reached higher than 100meq./kg.oil after 10 days storage without the addition of butanol, methanol, ethylacetate, hexane extracts at 0.1% level. Especially, the POV of soybean oils including butanol extract was 87.35meq/kg.oil after 10 days storage and antioxidant activity of butanol extract was shown to be superior to that of BHT. The pattern of the changes of the CDV of soybean oil after the addition of MLP extracts at 0.02%, 0.05% and 0.1%, respectively, were almost constant during 10 days of storage and then rapidly increased during the rest of experimental periods. During 10 days of storage in case of 0.1% adding level, the antioxidant activities of the butanol extract was superior to that of the each MLP extracts.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09b
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• pp.61-67
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• 2010

Thick soft clay deposits which are generally located at the west and south coast of the Korean peninsula have complicated characteristics according to their orientation and formation history. Thus, several geotechnical problems could possibly occur when those soft clay deposits are used as foundations for marine structures. Deep cement mixing (DCM) method is one of the most widely used soft soil improvement method for various marine structures, nowadays. DCM method injects binders such as cement into the soft ground directly and mixes with the in-situ soil to improve the strength and other geotechnical properties sufficiently. However, the natural impacts induced by dynamic motions such as ocean waves, wind, typhoon, and tusnami give significant influences on the stability of marine structures and their underlaying foundations. Thus, the dynamic properties become important design criteria to insure the seismic stability of marine structures. In this study, the dynamic behavior of cemented Busan clay is evaluated. Laboratory unconfined compression test and resonant column test are performed on natural in-situ soil and cement mixed specimens to confirm the strength and strain-dependent dynamic behavior variation induced by cement mixing treatment. Results show that the unconfined compressive strength and shear modulus increase with curing time and cement content increment. Finally, the optimized cement mixing ratio for sufficient dynamic stability is obtained through this study. The results of this study are expected to be widely used to improve the reliability of seismic design for marine structures.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.541-544
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• 2001

PC Box Girder was constructed by PSM(Precast Span Method) to solve the shortage of the construction period. The site case study was used in the PSM to find the construction productivity improvement. In this case study, main reasons of low productivity were founded unskilled technical engineers and insufficient equipment management winter season concrete curing condition. Productivity improvements are presented by assigning production personnel appropriately, motivation which increased by providing incentives for technical engineers, strictly cooperation of each participant, organizational teamwork, and Promoting productive work condition. Additional method of productivity improvements are continuous improvement of the work methods by considering the feedback on previous work, and continuous training to best handle the site conditions. This study of productivity improvement will help to use the most advantage of the PSM method and desire to successfully plan the future construction performance.