• Journal of the Korea Concrete Institute
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• v.21 no.6
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• pp.753-761
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• 2009

This paper presents the test results of total 24 beam-end specimens to investigate the effect of high-strength concrete and cover thickness on the development resistance capacity in tensile lap splice length regions. Based on bond characteristics that an increase in concrete strength results in higher bond stress and shortening of the transfer length, cracking behavior that thin cover thickness induced a splitting crack easily and brittle crack propagation, current design code that development length provisions as uniform bond stress assumption was investigated apply as it. The results showed that as higher strength concrete was employed, not only development resistance capacity was influenced by cover thickness, but also more sufficient safety factor reserved shorter than the lap splice length provision in current design code. From experimental research results, high-strength concrete development length was not inverse ratio of $\sqrt{f_{ck}}$ but directly inverse of $f_{ck}$, and it is also said that there is a certain limit length of the embedded steel over which the assumption of uniform bond stress distribution is valid specially for high-strength concrete not having a same embed length such as normal-strength concrete in current design criteria hypothesis.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.86-95
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• 2006

Brillouin backscatter is a type of reflection that occurs when light is shone into an optical fibre. Brillouin reflections are very sensitive to changes in the fibre arising from external effects, such as temperature, strain and pressure. We report here several case studies on the measurement of strain using Brillouin reflections. A mechanical bending test of an I beam, deployed with both fiber optic sensors and conventional strain gauge rosettes, was performed with the aim of evaluating: (1) the capability and technical limit of the DTSS technology for strain profile sensing; (2) the reliability of strain measurement using fiber optic sensor. The average values of strains obtained from both DTSS and strain gauges (corresponding to the deflection of I beam) showed a linear relationship and an excellent one-to-one match. A practical application of DTSS technology as an early warning system for land sliding or subsidence was examined through a field test at a hillside. Extremely strong, lightweight, rugged, survivable tight-buffered cables, designed for optimal strain transfer to the fibre, were used and clamped on the subsurface at a depth of about 50cm. It was proved that DTSS measurements could detect the exact position and the progress of strain changes induced by land sliding and subsidence. We also carried out the first ever distributed dynamic strain measurement (10Hz) on the Korean Train eXpress(KTX) railway track in Daejeon, Korea. The aim was to analyse the integrity of a section of track that had recently been repaired. The Sensornet DTSS was used to monitor this 85m section of track while a KTX train passed over. In the repaired section the strain increases to levels of 90 microstrain, whereas in the section of regular track the strain is in the region of 30-50 microstrain. The results were excellent since they demonstrate that the DTSS is able to measure small, dynamic changes in strain in rails during normal operating conditions. The current 10km range of the DTSS creates a potential to monitor the integrity of large lengths of track, and especially higher risk sections such as bridges, repaired track and areas at risk of subsidence.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.11
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• pp.1025-1033
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• 2011

In this paper, we introduce the contactless power transmission device for transmitting the power with the resonant characteristic of the cavity resonator. When transmitting the power, the contactless power transmission device begins to work in the condition where the transceiver adheres closely. The transceiver is electrically separated because there is no conductive terminal outside and the size of the receiver required for the electric power transmission can be minimized. The cavity resonator comprises slots for the input port and output port in the upper side conductor plate of the cavity and forms the input port and output port using the stripline structure at this upper part. The some of output port is separated from it and the electric power receiver is formed thus the union can be possible. The rest except electric power receiver become the electric power transmitter, which includes the input port of stripline-slot coupling, cavity, and the slot of the output port. If the transmitter and the receiver are combined, they become the form in which the electricity is transferred from the input port to the output port in a cavity resonator. The center frequency of the contactless power transmitter manufactured is 5.782 GHz. and $S_{21}$ is measured as -1.07 dB. It is confirmed that the high electric power transfer rate is approximately 78 %.

• 한국벤처창업학회:학술대회논문집
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• 2007.11a
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• pp.15-43
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• 2007

The object of this study is to present a strategy against technology protectionism of advanced countries focusing on international cooperation policy of KIPO and infringement of overseas intellectual property rights on the notion that a policy performed without a long-term plan will not lead to industrial growth in the long run. The number of dispute cases of intellectual property rights in Japan ranks first with 275 cases compared to that of other countries. Among the dispute case, the number of validation trial is 107 cases(38.9%), and correction trial is 83 cases(30.2%). The USA ranks second in dispute of intellectual property rights. Among the dispute of intellectual property rights in the USA, the number of validation trial is 66 cases(64.7%), and correction trial is 21 cases(20.6%). A strategy against technology protectionism of advanced countries is as follows. A strategy is required to cope with infringement of overseas intellectual property rights. Korean government has to strengthen the function of overseas intellectual property rights protection center, strengthen boundary restriction of infringement goods, promote international dispute study, train international dispute specialist, solve jurisdiction problem of patent court system, improve trial system, construct confidence as social capital etc. Enterprises have to maintain No Patent No Future policy, specialize on application and countermeasure against infringement dispute, participate for formation and standardization of Patent Pool, strive for specialization regarding technical transfer and license management.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.2
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• pp.161-168
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• 2011

The heating, ventilating, air conditioning (HVAC) system is a very important part of an automotive vehicle: it controls the microclimate inside the passenger's compartment and removes the frost or mist that is produced in cold/rainy weather. In this study, the numerical analysis of the defrost duct in an HVAC system and the de-icing pattern is carried out using commercial CFX-code. The mass flow distribution and flow structure at the outlet of the defrost duct satisfied the duct design specification. For analyzing the de-icing pattern, additional grid generation of solid domain of ice and glass is pre-defined for conductive heat transfer. The flow structure near the windshield, streakline, and temperature fields clearly indicate that the de-icing capacity of the given defrost duct configuration is excellent and that it can be operated in a stable manner. In this paper, the unsteady changes in temperature, water volume fraction, and static enthalpy at four monitoring points are discussed.

• Archives of Plastic Surgery
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• v.41 no.3
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• pp.253-257
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• 2014

Background Although the utility of flaps for the treatment of sternal wound infections following median sternotomy has been reported for 30 years, there have been few reports on the risk factors for complications after reconstruction. The objective of this investigation was to identify factors related to complications after the reconstruction of sternal wound infections. Methods A retrospective analysis of 74 patients with reconstructive surgery after sternal wound infection over a 5-year period was performed. Clinical data including age, sex, body mass index (BMI), comorbidities, bacterial culture, previous cardiac surgery, wound depth, mortality rate, type of reconstructive procedure, and complication rate were collected. Results The patients' BMI ranged from 15.2 to $33.6kg/m^2$ (mean, $23.1{\pm}3.74kg/m^2$). Wound closure complications after reconstructive surgery were observed in 36.5% of the cases. The mortality rate was 2.7%. Diabetes mellitus significantly affected the rate of wound closure complications (P=0.041). A significant difference in the number of complications was seen between Staphylococcus aureus (S. aureus) and coagulase-negative Staphylococci (P=0.011). There was a correlation between harvesting of the internal thoracic artery and postoperative complications (P=0.048). The complication rates of the pectoralis major flap, rectus abdominis flap, omentum flap, a combination of pectoralis major flap and rectus abdominis flap, and direct closure were 23.3%, 33.3%, 100%, 37.5%, and 35.7%, respectively. Conclusions Diabetes mellitus, S. aureus, harvesting of the internal thoracic artery, and omentum flap were significant factors for complications after reconstruction. The omentum flap volume may be related to the complications associated with the omentum flap transfer in the present study.

• Korean Journal of Childcare and Education
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• v.9 no.4
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• pp.107-133
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• 2013

The purpose of this study was to examine and compare the perceptions of mothers about the Nuri curriculum for 5-year olds. The subjects were 382 mothers whose 3-5-year old children went to kindergartens (192 mothers) and daycare centers (190 mothers). The findings were as follows: First, the majority of the mothers knew that the Nuri curriculum for 5-year olds started to be carried out in 2012, but many of them weren't told about the details at all. Second, the mothers considered the Nuri curriculum necessary, and were roughly satisfied with the ongoing Nuri curriculum for 5-year olds. Third, there was no difference in the mothers' perceptions of environmental factors required for the Nuri curriculum. Fourth, the mothers whose children went to kindergartens chose warm and enthusiastic character as important quality of teachers. The mothers whose children went to daycare centers chose friendly and caring character as important qualities of teachers. Fifth, the mothers perceived that the Nuri curriculum was relatively useful for the qualitative improvement of early childhood education and childcare. Sixth, the majority of the mothers didn't have their children transfer to another early childhood education institution after the Nuri curriculum for 5-year olds was carried out.

• Journal of Bio-Environment Control
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• v.26 no.3
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• pp.215-220
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• 2017

This study was conducted to improve the insufficiency of fruit vegetable grafting system developed by National Institute of Agricultural Sciences, Rural Development Administration. When the rotary blade cut the stem of scions and rootstocks, the grafting failure at curved cutting surfaces happened. The cutting depth of a tomato seedling by a rotated cutter was calculated 0.11 mm even when the cutting arm length and the maximum stem diameter were 50 mm and 5 mm, respectively. Mathematical analysis and high-speed photography showed that there was no problem by cutting in straight the stem of scions and rootstocks. The compression test of seedling stems to design the optimal shape of gripper showed that stems were not completely restored when they were compressed above 0.8 mm and 0.6 mm in case of rootstocks and scion, respectively. This study found that the bending angle of stem of tomato seedlings at the grafting period was 10 degree on average. The optimal gripper finger was the edge finger type which could be precisely set center point by adjusting the distance between fingers. In addition, it was found that most of seedling could be grasped without damage when the finger-to-finger distances is set to 2.5 mm for scion and 3.0 mm for rootstocks and finger are coated by 1 mm-thick flexible material.

• Journal of Korean Society of Forest Science
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• v.84 no.1
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• pp.41-47
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• 1995

A micropropagation system for black Locust(Robinia pseudoacacia) was established by using shoots and pin-punctured leaves of in vitro germinated seedlings. The greatest number of shoots (an average of 10.5 shoots) was obtained when shoot tips were cultured on MS medium supplemented with 1.0 mg/l BAP and 0.01 mg/l NAA. When pin-punctured leaf explants were cultured on the same medium, mean number of 13.5 shoots were produced. Shoot growth was accelerated by adding 50 mg/l of silver nitrate ($AgNO_3$), an anti-ethylene compound to the culture medium. Each shoot was excised from the mass and transferred onto half strength MS medium for rooting. Zygotic embryos at different developmental stages were cultured on LS medium supplemented with various growth regulators to induce somatic embryos. When cultured on LS medium with 1.0 mg/l 2,4-D. 14.3% of the zygotic embryos induced somatic embryos. Upon transfer onto the basal medium, somatic embryos sporadically converted into plantlets.

• Journal of Bio-Environment Control
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• v.13 no.3
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• pp.143-148
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• 2004

The automatic operating system was designed and built to work manless multipurpose in greenhouse. The system proved to be a reliable system for performing multipurpose functions. Its development involved the integration of moving part, height control part, watering part, ventilation part and inhalation part. The moving part was able to be moved it on the rail installed in greenhouse, the height control part controled it up and down by height of the crops, the watering part sprinkled a agricultural medicines on the crops and the ventilation and the inhalation part ventilated and inhaled different thing and vermin which were attached on crops. Based on the results of this study the following conclusions were made: The moving velocity was changed 0.047 - 0.027 m/s by the dial transfer. The velocity within 50 cm from center of the entrance was 0.2 m/s. The watering volume of spray increased as the pressure of spray was high. The difference of spray pressure between 10 kg/$\textrm{cm}^2$ and 15 kg/$\textrm{cm}^2$ was 60 ml, but that of spray pressure between 15 kg/$\textrm{cm}^2$ and 20 kg/$\textrm{cm}^2$ was 20 ml. The average speed of a current of inhalation was 3.64 m/s and the inhalation flux of inhalation was measured 0.044 ㎥/s by using glues seed and styrofoam.