• 한국잠사곤충학회지
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• 제31권1호
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• pp.20-24
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• 1989

7개 누에 품종으로 이면교잡하여 42개의 조합의 F1, F2세대에 대한 양적형질의 잡종강세와 약세현상을 검정한 결과는 다음과 같다. 잡종강세가 대체로 높은 형질은 견사량이 F1, F2세대의 I·II집단에서 15.57-38.69%, 단견중과 견층중은 F1, F2세대의 I·II집단에서 각각 11.29-21.65%, 7.44-23.73%로 정의 유의인데 반하여 5령경과와 연감율은 F1, F2세대의 I·II집단에서 각각 -0.57--6.62%, -1.74--6.06%의 부로 유의하였다. 단견중, 견층중, 견사장, 견사량 등의 수량적 형질은 F1세대가 F2세대보다 또 교배 I집단이 교배 II집단보다 높은 강세를 보였다. 큰 친에 대한 Heterobeltiosis는 단견중이 F1세대의 I·II집단에서, 견사량이 F1세대의 I집단에서 각각 정으로 유의하였고, 5령경과, 견층비율, 연감율은 F1, F2세대의 I·II집단에서 각각 부로 유의하였다. Inbreeding depression현상은 견층비율과 연감율이 교배 I·II에서 유의하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1353_1354
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• 2009

The OTFT devices had inverted staggered structures of Au/pentacene/ppMMA/ITO on PET substrate. The overall device performances of the flexible devices such as the operating voltage, the field effect mobility, the on/off ratio and the off current are somewhat worse than those of devices fabricated on glass substrates. Pentacene/ppMMA OTFT benchmarks (mobility, sub-threshold slope, on/off ratio) were comparable to that of solution cast PMMA, but below average when compared to other polymer gate dielectrics. However, threshold and drive voltages were among the lowest reported for a polymer gate dielectric, and surpassed only by ultra-thin SAM gate dielectrics.

• Bulletin of the Korean Chemical Society
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• 제26권10호
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• pp.1555-1559
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• 2005

High-performance fluorescent probes which exhibit either on/off or dual color fluorescence switching in response to the presence of organic vapors with a rapid response, a high sensitivity and a high-contrast on/off signaling ratio were demonstrated on the basis of the vapor-controlled AIEE phenomenon.

• Transactions on Electrical and Electronic Materials
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• 제12권6호
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• pp.241-244
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• 2011

An isolator transmits light in the forward direction and blocks light from passing in the reverse direction. It is regarded an essential optical component in medical, industrial, and research lasers for blocking reflection beams that cause optical damage and noise. It is also used as a communicative light intensifier to expand the lifespan of devices and enhance transmission quality. This study analyzed the characteristics of the core components in the construction of a polarization-independent isolator, namely, the walk-off polarizer and the Faraday rotator. Measurement of the extinction ratio of the resultant walk-off polarizer revealed that the ratio between the vertical and horizontal rays was 1,050:1 with a laser output of 0.032 W and 1,010:1 with a laser output of 2.68 W, thus presenting ratios similar to 1,000:1. In addition, the walk-off polarizer and Faraday rotator constructed in this study were used to compare output changes according to changes in power of input light and to check the penetration ratio. Results from the study presented variations in output value according to changes in power of input light. However, the average penetration ratio remained relatively consistent (~81.4%).

• The Journal of Korean Physical Therapy
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• 제26권5호
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• pp.280-289
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• 2014

Purpose: This study was conducted in order to determine the stimulation variables which should be considered when neuromuscular electrical stimulation (NMES) is applied for a muscle under the normal innervation to minimize muscle fatigue and increase force-generating ability. Methods: A total of 23 healthy men participated in the study and all subjects were randomly assigned to the 1:1 group, 1:3 group, 1:5 group, and control group with on-off ratio of NMES. The subjects performed a fatigue task, consisting of 10 times of isometric contraction sustained by NMES. NMES using Russian current stimulation was applied to muscle fatigue and divided into three sessions by pulse frequency (10 bps, 30 bps, 90 bps). The EMG was recorded using an MP 100 system from the quadriceps femoris muscle in four groups. Results: The differences of delta MdF and delta MF of between on-off ratio groups of 10 bps, 30 bps, and 90 bps pulse frequencies were very significant (p<0.05). According to the results of post hoc of 10, 90 bps, it was greater in the 1:1 group and the 1:3 group compared with the 1:5 group, and no fatigue was observed in the control group. In 30 bps, it was greater in the 1:1 group compared with 1:3, 1:5, and control group (p<.05). Conclusion: Among NMES variables to minimize muscle fatigue, the larger on-off ratio by pulse frequency showed the lower muscle fatigue. Therefore, on-off ratio needs to be great enough, and will be more efficient with the frequency 30 bps rather than of 10 bps and 90 bps.

• 한국통신학회논문지
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• 제38B권10호
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• pp.832-842
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• 2013

Cognitive Radio has attracted intensive interests of the researchers, recently. The data rate always increases in the emerging technologies. The increased data rate poses mainly two challenges for spectrum sensing. One is that the state of primary user (PU) is fast and alternatively varying between "on/off" in a spectrum sensing window. The other is that the asynchronicity among the reports in a cooperative spectrum sensing setting becomes more apparent. Both of them would deteriorate the spectrum sensing performance. Thus, we propose an asynchronous cooperative spectrum sensing method to cope with these two challenges. A likelihood ratio test based spectrum sensing is developed for a single cooperator. The likelihood ratio is obtained in the setting of fast varying PU state. The likelihood ratio test is uniformly powerful according to the Neyman-pearson lemma. Furthermore, the asynchronicity among the cooperators are studied. Two sets of fusion weights are discussed for the asynchronous time among cooperators. One is designed based on the condition probability of the PU state variation and the other one is designed based on the queueing theory. The simulation results are provided with different fusion methods. The performance improvements are demonstrated.

• 대한전자공학회논문지SD
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• 제44권11호
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• pp.15-19
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• 2007

OTFTs (Organic Thin Film Transistors)의 구동에 있어, 게이트 절연막 표면과 채널의 계면상태가 소자의 전기적 특성에 큰 영향을 미치게 된다. OTS(Octadecyltrichlorosilane)등과 같은 습식 SAM(Self Assembly Monolayer)를 이용하거나, $O_2$ Plasma와 같은 건식 표면 처리등 여러 표면 처리법에 대한 연구가 진행되고 있다. 본 논문에서는 pentacene을 진공 증착하기 전에 게이트 절연막을 $O_2$ plasma와 Ar ion beam을 이용하여 건식법으로 전처리 한 후 표면 특성을 atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS)를 사용하여 비교 분석하였고, 각 조건으로 OTFT를 제작하여 전기적 특성을 확인하였다. Ar ion beam으로 표면처리 했을 때, $O_2$ plasma처리했을 때 보다 향상된 on/off ratio 전기적 특성을 얻을 수 있었다. 표면 세정을 위하여 $O_2$ plasma 처리시 $SiO_2$ 표면의 OH-기와 반응하여 oxide trap density가 높아지게 되고 이로 인하여 off current가 증가하는 문제가 발생한다. 불활성 가스인 Ar ion beam 처리를 할 경우 게이트 절연막의 세정 효과는 유지하면서, $O_2$ Plasma 처리했을 때 증가하게 되는 계면 trap을 억제할 수 있게 되어, mobility 특성은 동등 수준으로 유지하면서 off current를 현저하게 줄일 수 있게 되어, 결과적으로 높은 on/off ratio를 구현할 수 있다는 것을 확인하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표대회 논문집(III)
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• pp.668-673
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• 1998

The specimen of current study has the same type with the 3-span slabs of Burns et al used in the study by Mojtahedi/Gamble, which laid a ground for the revision of the ACI318-77 code to the ACI 318-83 code. But those specimens was failed prematurely before it reached the ultimate strength which the specimen had. The reason is that bonded reinforcements were cut off where there is no need for the flexural reinforcement. As results. the slabs failed ultimately where the reinforcements was cut off. Thus, the tendon stresses of failure may have been much smaller than the values which culd reach if the bonded reinforcements were extended beyond the theoretical cut off points. On the based on the fact mentioned above. the specimens which had the same conditions as the specimens of Burns et al were used in the current study, but in which the reinforcements were distributed in a sequence for the reinforcements not to be cut anywhere in the 3-span. As a results, it was known that the current ACI code, revised by the result of Mojtahedi/Gamble's study, overestimated the effect of span/depth ratio on the members with high span/depth ratio. Thus it was concluded that the effect of span/depth ratio on the ultimate stress of unbonded tendon regulated by the current ACI code must be reconsidered and reevaluated.

• 대한전자공학회논문지SD
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• 제37권9호
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• pp.23-30
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• 2000

본 논문에서는 InGaAs/InAlAs 다중 양자우물을 이용한 두가지 타입의 비대칭 Fabry-Perot 전광 스위치에 대한 해석을 시도하였다. 전광 스위치의 동작을 해석하기 위해서 먼저 양자우물의 광 흡수계수와 굴절율의 변화 특성을 계산하였다. 양자우물의 비선형성 해석 결과를 토대로 전광 수위치의 ON/OFF 비와 스위칭 속도를 비교하였다. 시뮬레이션 결과로부터, DBR을 이용한 구조의 전광 수위치는 DBR이 없는 형태의 전광 수위치보다 ON/OFF 비를 향상시킬 수 있을 뿐만 아니라 스위칭 시간도 단축시킬 수 있음을 알 수 있었다.

• 한국자동차공학회논문집
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• 제4권3호
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• pp.102-111
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• 1996

For the air-fuel ratio control in a fuel injection SI engine, the Jump-Ramp control algorithm has been widely adopted by using the on/off type oxygen sensor. But the Jump-Ramp control method has limitation on treating the frequency and amplitude of the air-fuel ratio oscillation. This study suggests another feedback control logic named modulated fuel feedback control, which has a concept of pre-tuned air-fuel ratio oscillation. In the modulation method, the oxygen sensor output is not treated as on/off signal but as analog signal for feedback. By using the modulation method, the frequency and the amplitude of air-fuel ratio oscillation can be adjustable to some extent for improving the conversion efficiency of the Three-Way Catalyst. The result shows that the performance of the modulation method is better than that Jump-Ramp control method in reducing the amplitude of the air-fuel ratio oscillation as well as in increasing the frequency of the air-fuel ratio oscillation.