• 한국공작기계학회논문집
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• 제15권2호
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• pp.51-58
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• 2006

Laser welding of dissimilar metals has been widely used to improve a wear resistance and a corrosion resistance of the industrial parts. The objective of this research works is to investigate the influence of the process parameters, such as the welding for SM45C and STS304 with CW Nd:YAG lasers. The bead-on-plate welding tests are carried out for several combinations of the experimental conditions. In order to quantitatively examine the characteristics of the dissimilar welding, the welding quality of the cut section, stain-stress behavior and the hardness of the welded part are investigated. From the results of the investigation, it has been shown that the optimal welding condition without defects in the vicinity of the welded area and with a good welding qualify is 1600W of the laser power, 0.85m/min of welding speed and $4{\ell}/min$ of pressure for shielding gas.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.II
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• pp.109-116
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• 2000

The objective of this study is to measure rim surface adhesion and to calculate motion resistance produced by the adhesion acting on the rim section of a circular wheel under sticky soil condition. The mechanisms of generating motion resistance by the adhesion on a circular wheel were analyzed through wheel motion. Experiments were conducted in an indoor soil bin that contains loam soil. A circular steel wheel was used for experiments. A part of the wheel rim was cut off, and transducers which can measure normal and tangential forces were installed in this section. Calculated motion resistance at a part of the rim section was superposed for one wheel rotation as motion resistance produced by the rim surface adhesion. The motion resistance increased with increasing the dynamic load. Ratio of the motion resistance to total motion resistance measured by an axis transducer was about 23 to 46 % in this study.

• 한국연초학회지
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• 제20권2호
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• pp.231-237
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• 1998

This study was carried out to investigate the effects of curing methods on the concentration of ammonia during curing in burley tobacco leaves. The air-cured tobacco(KB108; Nicotiana tabacum L.) was grown at Chonju Tobacco Experiment Station in 1998 and the tenth leaves from the top on the stalk were harvested. Half of the harvested leaves were cured in normal air curing facility and the other leaves were cured in excessive curing facility. Stalk cut tobaccos were cured in horizontal curing facility. The leaves were sampled every five days from harvesting time to the end of curing(25 days). Ammonia concentration of leaves increased during curing period with a remarkable increase at yellowing stage. The concentration of ammonia was high in the primed cured leaves, while that of the excessive cured leaves was low. It is considered that the lower increase of ammonia in stalk cured leaves may be caused by the translocation from the leaves to the stalk during curing, while that of excessive cured leaves may be caused by the poor decomposition of protein and amino acid during curing by excessive moisture loss and high temperature condition.

• 한국초지조사료학회지
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• 제10권1호
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• pp.36-41
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• 1990

The more N fertilizer, the more grass proportion (58 8, 240 kg N/ha) and the less white clover (Trifolium repens) (6 %, 240 kg N) under grazing utilization. The proportion of white clover was maintained about 27 % at 60 kg N/ha/yr and weed proportion was reached 33 %. Under the condition of differentiated N rates, the proportion of white clover was ranged from 10 to 36 % at 20 kg N/ha/cut which was allocated after every grazing and it probably dependent on differentiated N rates rather than total amounts of N applied annually. 53-74 % of total dry matter yield were concentrated at 1st and 2nd growth under grazing system and there were no great differences in dry matter yield at 3rd, 4th, and 5th growth in comparison with the variations of N rates. There was very significant relationship between the proportions of white clover and the amounts of N uptaken by herbage upto 180 kg N/ha. About 138 kg N/ha were uptaken by herbage without N fertilizer but only with white clover (31 %) as a substitute of N. In the amounts of crude fiber and crude protein by differentiation of N fertilizer, there were no any great variations and liveweightgain during grazing periods was reached 1583 kg liveweightlha.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.640-648
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• 2009

Recently the truction of coastal reclaimation work has been extensively implemented in Korea. The Sondo New City is being established on the reclaimed land from the sea, construction companies of metro construction are planing to pull-out the sheet pile for saving the construction cost. In the case of soft marine clay, it is very difficult to pull-out the sheet pile by using the hydraulic hammer difficult. Therefore, the man of the field must be aware of vibration effect to the ground and the structure. For understanding the vibration effect to the ground during subway construction, the model was formulated with 1/25 braced-cut for subway construction. Scott and Iai(1989) proposed the law of the similarity for other experimental conditions. The laboratory model test was conducted under the vibration condition of sheet pile pulling out. The settlement on the ground surface was measured during the shaking table test. The pore water pressure was also monitored in the upper, middle, and lower layers of soil. The field settlement level and the pore water pressure can be predicted by using the results of the laboratory shaking table test.

• 한국구조물진단유지관리공학회 논문집
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• 제6권2호
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• pp.175-182
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• 2002

The cement injection technology on the purpose of ground reinforcement and cut-off has been used in construction sites until now. However, recently it is applied to prevent leakage of underground structure. In this study, applicability of the back side waterproof grouting method was verified through performing field model tests and reviewing case histories. From the results of this study, injection shape of the back side waterproof grouting method was appeared to be root type, and waterproof effect by injection of cement grout material was excellent because grout material infiltrated into boundary between wall of structure and back side ground to be waterproof layer. Components influencing infiltration of injection material are type of soil and degree of compaction. For effective injection, injection pressure has to vary gradually from high pressure to low pessure and small quantity of injection material has to be injected for long times. Also, spacing of injection hole must be designed considering condition of back side ground, injection area, W/C ratio, the number of injection and injection pattern properly.

• 한방재활의학과학회지
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• 제21권4호
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• pp.269-279
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• 2011

Objectives: The purpose of this study was to investigate the clinical application of blood-letting therapy and oriental medicine with arteriosclerosis obliterans. Methods: The patient in this case had been already treated by anticoagulation, percutaneous transluminal angioplasty and thrombolysis. But these methods didn't work on patient and condition had gone bad. Finally the patient's left limb was about to be amputated. Patient did not wall to cut off her lower limb, so she visited us to find a way for treating and preserving her lower limb. A drastic treatment was necessary in this situation. We treated the patient with Korean traditional treatment. Specially excessive blood-letting therapy and oriental medicine helped the patient to decrease the pain, numbness and frigidity. Results: After treatment the chief complaint and accompanying symptoms were subsided and improved. And personal and social performance scale was increased. Conclusions: According to this study, Korean traditional treatment such as blood-letting therapy, and oriental medication is effective for the cure of arteriosclerosis obliterans. During this period, foot necrosis was delayed and amputation is not needed any more.

• 전기학회논문지
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• 제62권1호
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• pp.140-142
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• 2013

Cognitive radio (CR) has been recently proposed to dynamically access unused-spectrum. Since the spectrum availability for opportunistic access is determined by spectrum sensing, sensing control is identified as one of the most crucial issues of cognitive radio networks. Out-of-band sensing to find an available channels to sense. Sensing is also required in case of spectrum hand-off. Sensing process needs to be done very fast in order to enhance the quality of service (QoS) of the CR nodes, and transmission not to be cut for longer time. During the sensing, the PU(primary user) detection probability condition should be satisfied. We adopt a channel prediction method to find target channels. Proposed prediction method combines chaotic global method and chaotic local method for channel idle probability prediction. Global method focus on channel history information length and order number of prediction model. Local method focus on local prediction trend. Through making simulation, Proposed method can find an available channel with very high probability, total sensing time is minimized, detection probability of PU's are satisfied.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 추계종합학술대회
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• pp.208-211
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• 2005

This paper presents an ultra-low partial discharge(PD) measurement system that has been accepted as a non-destructive method to estimate electrical insulation of low-voltage electric devices. The PD measurement system is composed of a coupling network, a low noise amplifier, and associated electronics. A shielding box is used to make a better condition against electromagnetic interference. A low cut-off frequency of the coupling network was 1MHz(-3 dB). Calibration tests on laboratory set-up have shown that the PD measurement system has a stable sensitivity of 11.4mV/pC. In an application experiment on a low-voltage induction motor(5HP), we could detect 0.77pC level of partial discharge pulse at the applied voltage of AC 664 V$_{peak}$.

• 한국작물학회지
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• 제22권1호
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• pp.70-79
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• 1977

1. 다년생잡초의 지하경은 단일처리만으로서도 형성되었는데, 단일조건별(시간)로는 11시간까지는 형성량에 큰 차이가 없었다. 2. 다년생잡초 지하경형성을 위한 단일처리의 유도 기간은 잡초종류에따라 차이가 있었는데 벗풀은 2일, 올방개와 너도방동산이는 10일 가래는 30일이었다. 3. 다년생잡초 지하경의 절단정도와 상아발육정도를보면 잡초종류간에 다소 차이가 있었고, 절단방법별로도 차이가 있었다. 그러나 공시잡초 모두 80%절단구에서도 완전히 맹아력을 상실하지는 않았는데 가래는 8%, 올방개는 13%, 벗풀은 100%의 맹아발생율을 보였다. 4. 토양 조건에 따른 발아성을 보면 너도방동산이는 담수상태하에서는 맹아발육이 되지 않았으며, 가래는 너도방동산이와는 반대로 담수상태하에서만 맹아발육되었다. 그러나 올방개, 벗풀은 담수, 포화상태에서 다같이 맹아ㆍ발육되었으나 담수상태하에서 더욱 용역하게 맹아 발육되었다.