• Journal of the Korea Concrete Institute
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• v.22 no.1
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• pp.113-122
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• 2010

Corrosion of prestressing tendons and wire fractures in grouted post-tensioned prestressed concrete bridges have been considered as a serious safety problem. In bridge evaluation the condition of prestressing tendons should be inspected, and if corroded tendons are found, the loss of tendon area should be included when we calculate the ultimate strength. In the previous study, it was evaluated that continuous acoustic monitoring techniques could be considered as a reliable non-destructive method for detecting wire fractures of fully grouted post-tensioned prestressing tendons. In the present study, an experimental test was performed for detecting wire fractures of post-tensioned prestressing tendons which are prestressed lower than current design level. A 10 m prestressed concrete beam was fabricated, which included two tendons prestressed 66 percentage and 40 percentage of tensile strength, respectively. The corrosion of two tendons was induced by an accelerated corrosion equipment and the test beam was monitored by using seven acoustic sensors and a continuous acoustic monitoring system. From each prestressing tendon, two acoustic signals of wire fractures were successfully detected and source locations were estimated within 20 mm error. Based on the test results, it is considered that continuous acoustic monitoring techniques can be applied to detect low-prestressed wire fracture in fully grouted post-tensioned prestressed concrete beams.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.1
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• pp.77-85
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• 2001

This paper was to investigate the preparation of polysulfone(PS), polyethersulfone(PES) and polyphenylsulfone(PPS) membrane. The thermal property of PPS was higher than that of others. From the result of SEM, the concentration of polymer was found to have a significant effect on the structure of membrane, and the structure of membrane made of PES is found to have regular micell form of asymmetry. Permeability and selectivity for oxygen and nitrogen gas in the air were analyzed by GC. Permeabilities of the membrane made of PES for oxygen and nitrogen in air, 1.5 and $0.7(x10^9[cm^3(STP)cm/cm^2seccmHg]) $, respectively was higher than that of others. and Selectivity of the membrane made of PPS for oxygen to nitrogen gas in air was 2.9.

• Journal of the Korea Concrete Institute
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• v.26 no.3
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• pp.267-275
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• 2014

Recently, the construction of curved bridge has increased, thus researchers perform the analytic studies on PSC curved bridge. However, the grid analysis method that are mostly used in the construction industry is not adequate to acquire the precise behavior evaluation of curved PSC briges. Therefore, the precise finite element analysis considering the effective variables were performed to establish the basis for the design method of curved PSC bridge by using 3D elements and bar element. The evaluated variables in this analysis were the number of girders, loading point, section figure, change of prestressing force. The results show the load carrying capacity of the 3 girder type bridge is 200% of that of the 2 girder type, and that applying load on outer girder makes the load resistance capacity and the deflection deviation of 2 girders smaller. The structural capacity of the bridge is improved when the section size is increased, but the efficiency of it is not sufficient enough compare to that of the change of prestressing forces. The change of prestressing forces shows that the camber and the load carrying capacity are linearly increased as PS force is increased. Moreover, when the PS force applied on outer girder is increased than that of inner girder, the deviation of deflection the girders decreases, thereby the stability of the bridge is enhanced.

• Journal of the Korean Society of Food Culture
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• v.19 no.3
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• pp.295-312
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• 2004

This study is to investigate the trend of researches on food and culture from 1990 to 2003. With a literary approach, this paper analyzes how many papers were published and what was the major research subject. We classified the journals published during this time into 10 different categories and we are to grasp a research trend. 1) Historical approach on the traditional food and food habit; 2) Globalization of Koran food; 3) Use and preparation for traditional food; 4) Table setting and table manner; 5) Provincial cuisine; 6) Traditional festive food or celebratory meal; 7) Religious food; 8) Fusion food; 9) Food and culture in foreign countries and food habit of Korean people living abroad; 10) Studies related with satins out. It was revealed that 268 papers(=ps) were published. Eating out was the most frequently reported subject(100 ps), followed by provincial cuisine(54 ps), use and preparation for traditional food(49 ps), food habit for foreign people and Korean people living abroad(22 ps). Researches on these 4 topics have been accelerated since the late half of 1990s. This reflects the social factors such as rapid growth of food service industry, settlement of local autonomy, popularization of leisure activities and accelerated introduction of foreign food and culture. Half of the studies on the eating out dealt with eating out behavior. And 30 papers were reports on the food service industry situations. More than half of the studies on the provincial cuisine(26 ps) were concentrated on digging out recipes. Studies on the use and preparation for traditional food were mainly about what kind of food and how often the food is used(17 ps). Kimchi was the most frequently studied food. There were 11 papers regarding food and culture in foreign countries. Most of the authors were historians or linguists. Food habit of Korean people living abroad were investigated in 7 papers. There was few studies on fusion food, table setting and table manner. This doesn't meet with increasing demand for specialized information in then fields. Researches on the traditional festive food or celebratory meal(5 ps) and religious food(9 ps) were negligible. Papers on the historical approach to the traditional food and food habit were limited(12 ps). Moreover, most of them were patchwork of existing literatures. Continuous researches to exploit the historical facts based on literary proof should be tried with patience. Otherwise, the papers will copy the hackneyed knowledge repeatedly. Globalization of Korean food means the development of Korean food for foreign people and export of them worldwide. Only 16 papers were reported on this subject, 14 of them were published after 2000, 8 of them were surveys on the foreigners' food preference. In order to get practical informations on what we develope and how we sell for the foreign customers, profound research on their food habit should be done.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.95-98
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• 2012

This paper describes a multiphase delay-locked loop (DLL) that generates a 32-phase output clock over the operating frequency range of 40 MHz to 280 MHz. The matrix-based delay line is used for high resolution of 1-bit delay. A calibration scheme, which improves the linearity of a delay line, is achieved by calibrating the nonlinearity of the input stage of the matrix. The multi-phase DLL is fabricated by using 0.11-${\mu}m$ CMOS process with a 1.2 V supply. At the operating frequency of 125MHz, the measurement results shows that the DNL is less than +0.51/-0.12 LSB, and the measured peak-to-peak jitter of the multi-phase DLL is 30 ps with input peak-to-peak jitter of 12.9 ps. The area and power consumption of the implemented DLL are $480{\times}550{\mu}m^2$ and 9.6 mW at the supply voltage of 1.2 V, respectively.

• The Journal of Korean Physical Therapy
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• v.26 no.5
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• pp.290-295
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• 2014

Purpose: The purpose of this study was to assess the effects of robo-horseback riding with changes of pelvic tilting and speeds on muscle activities of trunk and lower limb in healthy adults. Methods: Thirty healthy adults were recruited for this study. Subjects performed robo-horseback riding at three pelvic postures (anterior tilting pelvic posture: AP, neutral pelvic posture: NP, posterior pelvic posture: PP) and different speeds (moderate and fast speed). Muscle activities were recorded from the trunk muscles (rectus abdominis [RA], T2 paraspinalis [T2 PS], L2 paraspinalis [L2 PS]) and lower limb muscles (rectus femoris [RF], vastus medialis [VM], vastus lateralis [VL], biceps femoris [BF], gastrucnemius [GCM]). Results: Significantly higher RA activities were observed under the PP condition than under the AP and NP conditions at both speeds. Significantly higher L2 PS activities were observed under the AP condition than under the PP and NP conditions at both speeds. Significantly higher T2 PS activities were observed under the AP condition than under the PP and NP conditions at fast speed. However, the muscle activities of the VM and GCM did not show significant changes with changes in pelvic posture at both speeds. All muscle activities were significantly higher under the fast speed than under the moderate speed in three pelvic postures. Conclusion: There were significant differences in the changes of pelvic tilting on muscle activities of trunk and lower limb were observed in healthy adults. NP condition can be introduced the most efficienct posture for muscle activities of trunk and lower limb in robo-horseback riding.

• Journal of the Korean institute of surface engineering
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• v.43 no.3
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• pp.121-126
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• 2010

The PS(porous Si) were fabricated with different anodization time and current density. The structural and optical properties of PS were investigated by SEM(scanning electron microscopy), AFM(atomic force microscopy), and PL(photoluminescence). It is found that the pore size and surface roughness of PS are proportional to the current density. The PL spectra show that the PL peak position is red-shifted with increasing anodization time. This behavior corresponds to the change of pore size which is consistent with the quantum confinement model. The FWHM(full width at half maximum) of PL peak is decreased from 97 to 51 nm and the PL peak position is blue-shifted with increasing current density up to 10 mA/$cm^2$. The PL peak intensity of the PS fabricated under 1 mA/$cm^2$ is the highest among samples.

• Journal of Aquaculture
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• v.21 no.4
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• pp.325-330
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• 2008

Two different Eelwardsiella tarda isolates, KFE and Edk-2, were obtained from Korea and Japan respectively. On the base of the previous results showing higher pathogenicity of E. tarda KFE compared to that of E. tarda Edk-2 isolate, we tried to determine the differences of antigenicities of these two isolates in loach which is one of the important species in freshwater aquaculture in Korea. Concentration of specific antibody in the serum appeared to be much higher in loach immunized with FKC of E. tarda Edk-2 than those found in loach immunized with FKC of E. tarda KFE. Cross-reaction analysis using agglutination test with normal and antigen-absorbed antisera implied the differences epitopes in the antigens of these E. tarda isolates. For the comparison of bactericidal activity of the produced antibody with different antigens, absorption analysis was performed and confirmed the presence of critical epitopes in the FKC of E. tarda KFE strain. The prophylactic agent, polysaccharide-bound protein (PS-K) injected 1 week before the artificial infection with E. tarda KFE isolates decreased the cumulative mortality in loach and would be on effective method to prevent the occurrence of bacterial infection including E. tarda.

• Journal of applied mathematics & informatics
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• v.38 no.1_2
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• pp.57-64
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• 2020

Let R ⊆ T be an ascending chain of commutative rings with identity and H(R, T) (resp., h(R, T)) the composite Hurwitz series ring (resp., composite Hurwitz polynomial ring). In this article, we give some conditions for the rings H(R, T) and h(R, T) to be PS-rings.

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.05a
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• pp.109-109
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• 2002

Alzheimer's disease (AD) is characterized by $\beta$-amyloid deposition and associated with loss of neuron cells in brain regions involved in learning and memory process. Many cases of early onset autosomal dominant inherited forms of AD are caused by mutation in the genes encoding presenilin-2 (PS-2).(omitted)