• Restorative Dentistry and Endodontics
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• 제39권2호
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• pp.104-108
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• 2014

Objectives: To evaluate the effect of passive ultrasonic agitation on the cleaning capacity of a hybrid instrumentation technique. Materials and Methods: Twenty mandibular incisors with mesiodistal-flattened root shape had their crowns sectioned at 1 mm from the cementoenamel junction. Instrumentation was initiated by catheterization with K-type files (Denstply Maillefer) #10, #15, and #20 at 3 mm from the working length. Cervical preparation was performed with Largo bur #1 (Dentsply Maillefer) followed by apical instrumentation with K-type files #15, #20 and #25, and finishing with ProTaper F2 file (Denstply Maillefer). All files were used up to the working length under irrigation with 1 mL of 2.5% sodium hypochlorite (Biodyn$\hat{a}$mica) at each instrument change. At the end of instrumentation, the roots were randomly separated into 2 groups (n = 10). All specimens received final irrigation with 1 mL of 2.5% sodium hypochlorite. The solution remained in the root canals in Group 1 for one minute; and ultrasonic agitation was performed in Group 2 for one minute using a straight tip inserted at 1 mm from working length. The specimens were processed histologically and the sections were analyzed under optic microscope (x64) to quantify debris present in the root canal. Results: The samples submitted to ultrasonic agitation (Group 2) presented significant decrease in the amount of debris in comparison with those of Group 1 (p < 0.05). Conclusions: The hybrid instrumentation technique associated with passive ultrasonic agitation promoted greater debris removal in the apical third of the root canals.

• ETRI Journal
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• 제37권1호
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• pp.128-137
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• 2015

In this work, a fishbone-type transmission line employing a comb-type ground plane (FTLCGP) was fabricated on polyethersulfone (PES) substrate, and its RF characteristics were thoroughly investigated. According to the results, it was found that the FTLCGP on PES showed periodic capacitance values much higher than other types of transmission lines due to a coupling capacitance between the signal line and ground, which resulted in a reduction of wavelength and line width. Using the theoretical analysis, we also extracted the bandwidth characteristic of the FTLCGP on PES. According to the result, the FTLCGP structure showed a cut-off frequency of 280 GHz.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2003년도 하계학술대회
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• pp.49-51
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• 2003

This test data informs to compare components from different manufactured coupler type. On the point of reliability, less than 1x8 output branching number, fuse type coupler was more stable than PLC type coupler. But more than 1x8 output branching number, PLC type coupler was more stable. This test data showed critical branching point, on the point of reliability.

• 기본간호학회지
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• 제15권3호
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• pp.360-370
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• 2008

Purpose: This study was done to identify factors (pain stress, perceived stress, pain disability, fatigue, depression) strategies used by elders to cope with pain based on their type of pain belief. Method: Data were collected from 314 elders in community settings in Seoul from September to December of 2007. Cluster analysis, t-test, and ANOVA were used to analyze data. Result: The types of pain belief were classified as the following groups: Self-blame, Enduring & Mysterious, and Short-term & Understandable. Perceived stress (t=2.36, p=.02), social support (t=2.24, p=.03), extent of pain relief (t=2.39, p=.02), and duration of pain relief (t=2.09, p=.04) were important factors for active and passive coping in the Self-blame group. Pain stress (t=2.39, p=.01) and depression (t=-3.99, p=.00) were significantly related to the active coping in the Enduring & Mysterious group. Perceived stress (t=2.55, p=.01) was an important factor in the passive coping in the Short-term & Understandable group. Conclusion: Considering different types of pain belief in elders and factors that are significantly related to different coping strategies, future nursing interventions should be population specific to encourage active coping strategies and to decrease passive coping strategies.

• 대한기계학회논문집B
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• 제21권1호
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• pp.174-184
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• 1997

A shock wave, being an irreversible process, gives rise to entropy increase. A great deal of effort has been made to control shock wave and boundary layer interaction related to energy losses as well as problems of vibration and noise. In the present study, tests are performed on a roof mounted half circular arc in an indraft type supersonic wind tunnel to evaluate the effects of porosity, length and depth of cavity in passive control of shock wave on the attenuation of shock strength by reviewing the measured static pressures at the porous wall and cavity. Also the flow field is visualized by a Schlieren system. The results show that in the present study the porosity of 8% produced the largest reduction of pressure fluctuations and that for the same porosity, the strength of shock wave decreases with the increasings of the depth and length of cavity.

• 한국환경과학회지
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• 제23권8호
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• pp.1495-1505
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• 2014

The objective of this study was to evaluate survival rate and fish movement (migration) using a tagging approach of passive integrated transponder (PIT) in Juksan Weir, which was constructed as a four major river restoration projects. For this study, survival rates of each fish species and the mobility of fish individuals were analyzed during 2 weeks by the insertion of PIT tags to various fish species in the laboratory. According to tagging tests in the laboratory, the survival rate 37.5% (30 survivals of 80 individuals) after the insertion of PIT tags. The survival rate of Carassius auratus and Hemibarbus labeo was 100% and 80% after the insertion of the tags, respectively, whereas it was only 13.3% for Zacco platypus. In the field experiments of Juksan Weir, 6 species and 157 individuals from 8 species (563 individuals) were detected in the fixed automatic data-logging system, indicating a detection rate of 27.9% in the fishway of Juksan Weir. In the meantime, some species with no or low detection rates in the fixed automatic data-logging system were turn out to be stagnant-type species, which prefer stagnant or standing water to live.

• 전기학회논문지P
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• 제64권3호
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• pp.146-152
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• 2015

In this paper, we propose a boost DC-DC converter using a modification of the passive auxiliary resonant snubber circuit with a DC-DC converter in a typical active auxiliary resonant snubber-bridge inverter. The proposed boost DC-DC converter is small compared to the DC-DC converter according to the soft-switching scheme that requires a general auxiliary switch by realizing the soft switching operation as a DC-DC converter which does not require an auxiliary switch. It is light-weight, switch the turn-on and turn-off switching loss at the time of the superposition of the voltage and current is extremely small, so small. And the reduction of the surge voltage and current of the switch. In addition, the proposed boost DC-DC converter has a high efficiency over a wide load characteristics change area than conventional hard switching PWM boost converter using an RC snubber loss.

• 로봇학회논문지
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• 제12권2호
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• pp.107-115
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• 2017

In this paper, four-bar linkage mechanism for the knee joint is developed which is used in prosthetics. But unlike the prosthetics, the feature of this mechanism is that the instantaneous center of rotation of the four-bar linkages can be moved behind the ground reaction force vector so that it can be passively supported without any external power. In addition, this mechanism is developed similar to the structure of the human knee joint for eliminating the sense of heterogeneity of the wearer. In order to design the mechanism with these two objectives, optimization design process is done using the PIAnO tool and detailed design is carried out through optimized variable values. The developed mechanism is attached to the robot which can assist the hip and ankle joints. In order to verify the operation of the developed knee mechanism, an insole type sensor was attached to the shoes to compare data values before and after wearing the robot. Result data showed that wearer wearing the exoskeleton robot with the knee mechanism was the same value regardless of whether the heavy tool is loaded or not.

• 한국전자파학회논문지
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• 제21권11호
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• pp.1201-1207
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• 2010

이동 통신 서비스가 확대됨에 따라 인접 기지국 간의 간섭 문제가 증가하게 되었으며, 그에 따라 CDMA 시스템의 능동 상호 변조 왜곡(AIMD: Active Inter-Modulation Distortion)뿐만 아니라 수동 상호 변조 왜곡(PIMD: Passive Inter-Modulation Distortion)에 대한 문제도 기지국 안테나 시스템 설계 시 고려되어야 한다. 본 연구에서는 기지국 안테나에 사용되는 도체와 도체 조립에 있어 국부적인 전류 비선형을 유발하는 전류 밀도의 특성을 분석하였고, 전류 비선형성을 낮추기 위한 방법을 연구하였다. 이를 통하여 안테나 구조의 도체-도체 결합을 위한 넛트의 간격, 면적 등이 미치는 영향을 분석하여 수동 상호 변조 왜곡의 개선 방향을 제안한다.

• 한국환경보건학회지
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• 제39권2호
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• pp.151-158
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• 2013

Objective: This study was carried out to determine the depositional characteristics of pine needles, pine tree bark, moss, and soil, which are used as a passive air sampler (PAS) of atmospheric polychlorinated biphenyls (PCBs). Methods: All four media were sampled from the same site. PCB concentrations were analyzed by GC/MSD, and the lipid contents were measured using the gravimetric method. Results: The total PCB concentration (IUPAC No. 28, 52, 101, 138, 153, 180) was the highest in soil (227.97 pg/g dry), followed by pine needles (71.36 pg/g dry), pine tree bark (44.58 pg/g dry), then moss (21.91 pg/g dry). Pine needles contained the highest lipid contents (21.31 mg/g dry), whereas soil (10.01 mg/g dry), pine tree bark (4.85 mg/g dry), and moss (1.92 mg/g dry) contained less. The concentration of lower-chlorinated PCBs was relatively high in pine needles, pine tree bark and moss, but not in soil. The PCB concentrations were proportional to their lipid contents in pine needles, pine tree bark and moss, but a different trend was revealed in soil. Conclusions: The PCBs concentrations in the media were affected by various factors including atmospheric PCB concentrations, lipid contents, and depositional pathways. However, each of these factors had a varying influence depending on the type of medium.