• Restorative Dentistry and Endodontics
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• 제44권2호
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• pp.22.1-22.8
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• 2019

Objectives: The aim of this study was to investigate the effect of glide path preparation with PathFile and ProGlider nickel-titanium (NiTi) files on the cyclic fatigue resistance of WaveOne NiTi files. Materials and Methods: Forty-four WaveOne Primary files were used and divided into four groups (n = 11). In the first group (0 WaveOne), the WaveOne Primary files served as a control group and were not used on acrylic blocks. In the 1 WaveOne Group, acrylic blocks were prepared using only WaveOne Primary files, and in the PF+WaveOne group and PG+WaveOne groups, acrylic blocks were first prepared with PathFile or ProGlider NiTi files, respectively, followed by the use of WaveOne Primary files. All the WaveOne Primary files were then subjected to cyclic fatigue testing. The number of cycles to failure was calculated and the data were statistically analyzed using one-way analysis of variance (ANOVA) and the Tukey honest significant difference multiple-comparison test at a 5% significance level. Results: The highest number of cycles to failure was found in the control group, and the lowest numbers were found in the 1 WaveOne group and the PF+WaveOne group. Significant differences were found among the 1 WaveOne, PF+WaveOne, and control groups (p < 0.05). No statistically significant differences were found between the PG+WaveOne group and the other three groups (p > 0.05). Conclusion: Glide path preparation with NiTi rotary files did not affect the cyclic fatigue resistance of WaveOne Primary files used on acrylic blocks.

• 대한통합의학회지
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• 제5권2호
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• pp.43-50
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• 2017

Purpose : There is no validated method for measuring the toe flexor strength that can isolate the intrinsic muscles of the foot from the extrinsic muscles. This study compared the hallux flexion force (HFF) and muscle activity in the foot and ankle according to ankle position [plantarflexion (PF), neutral, and dorsiflexion (DF)]. Method : The study enrolled 17 subjects. In the sitting position, the HFF and activities of the abductor hallucis (AbdH), tibialis anterior (TA), and gastrocnemius (GCM) muscles were measured using a digital dynamometer and a wireless electromyography system, respectively. Subjects were instructed to flex the great toe maximally in three different ankle positions. Three 5-second trials were performed to measure the HFF and muscle activities in each condition. Repeated-measures ANOVA was used to compare the variables and paired t-tests with the Bonferroni correction were used for post-hoc pair-wise comparisons. The significance level was set at .016. Result : The HFF in DF was significantly greater than in any other ankle position (p<.01). The TA activity was greatest in ankle DF and that of the GCM was greatest in PF (both p<.01). However, there was no significant difference in AbdH activity according to ankle position. Conclusion : These results suggest that selective strength measurement of the foot intrinsic muscles in HFF should be performed with the ankle in the neutral position.

• Journal of Power Electronics
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• 제18권6호
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• pp.1642-1649
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• 2018

A single-stage flyback LED AC-DC converter based on primary-side control under constant current mode is proposed in this study. The proposed converter features low total harmonic distortion (THD) and high power factor (PF). It also consists of a zero-crossing distortion compensation circuit and a variable duty ratio control compensation circuit to deal with the line current distortions caused by fixed duty ratio control. The system model and layout are built in Simplis and Cadence, respectively. The feasibility and performance of the proposed circuit is verified by designing and fabricating an IC controller in the HHNEC $0.35{\mu}m$ 5 V/40 V HVCMOS process. Experimental results show that the PF can reach a level in the range of 0.985-0.9965. Moreover, the average THD of the entire system is approximately 10%, with the minimum being 6.305%, as the input line voltage changes from 85 VAC to 265 VAC.

• 한국작물학회지
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• 제29권2호
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• pp.114-117
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• 1984

경사휴에 의한 벼 품종간 내한발 포장검정방법의 가능성을 검토한 결과, 1. 경사휴 높이와 토양의 pf 치와는 Y=2.25+0.007 X(r=0.990${\ast}\;{\ast}$)의 관계였다. 2. 경사휴가 높아질수록 출수기는 지연되었고, 간장은 단축되었으며, 수량은 감소되었다. 그러한 정도는 품종간에 차이가 뚜렷하였다. 3. 출수 지연일수, 간장 단축률 및 수량 감소률에 의거 판정된 내한발성은 삼 남벼, 밀양26호, 진주벼, 농림나 1호는 강하였고, Knlb361-1-8-6-149는 약하였다.

• Wind and Structures
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• 제38권2호
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• pp.119-128
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• 2024

The aerodynamic damping is an essential factor that can considerably affect the dynamic response of the cable-stayed bridge induced by crosswind load. However, developing an accurate and efficient aerodynamic damping model is crucial for evaluating the crosswind load-induced response on cable-stayed bridges. Therefore, this study proposes a new method for identifying aerodynamic damping of the bridge structures under crosswind load using an extended Kalman filter (EKF) and the particle filter (PF) algorithm. The EKF algorithm is introduced to capture the aerodynamic damping ratio. PF technique is used to select the optimal spectral representation of the noise. The effectiveness and accuracy of the proposed solution were investigated through full-scale vibration measurement data of the crosswind-induced on the bridge's girder. The results show that the proposed solution can generate an efficient and robust estimation. The errors between the target and extracted values are around 0.01mm and 0.003^o, respectively, for the vertical and torsional motion. The relationship between the amplitude and the aerodynamic damping ratio is linear for small reduced wind velocity and nonlinear with the increasing value of the reduced wind velocity. Finally, the results show the influence of the level of noise.

• 한국식품영양과학회지
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• 제46권1호
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• pp.46-55
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• 2017

본 연구에서는 한약재의 장기보존을 위한 위생처리법으로 잘 알려진 감마선 조사 처리 시 독활 추출물의 항산화 활성에 미치는 영향을 검토하였다. 천연 약용식물인 독활의 감마선 조사 처리에 따른 조사 판별 marker 확인을 위해 광자극발광법, 열발광분석법, 전자스핀공명법을 이용하여 확인시험법의 판별 특성을 확인하였다. 그 결과 광자극발광법에서 비조사구 0 kGy에서 891.00 PCs의 중간시료 수치를 나타내어 광자극발광법 단독으로는 조사 여부 판별 확인이 어려운 것을 확인할 수 있었다. 하지만 열발광분석법, 전자스핀 공명법에서는 조사구와 비조사구 간의 차이를 명확히 확인할 수 있었으며, 이를 통해 한약재인 독활은 3가지 확인 시험법을 모두 적용하여 분석하는 것이 적합한 것으로 판단되었다. 에탄올 농도별 추출에서는 50% 에탄올에서 비조사구 0 kGy와 조사구 10 kGy에서 각각 5.98 mg/g, 6.86 mg/g의 함량을 나타내었다. 항산화 활성 확인을 위해 추출물의 phenolic 농도를 $50{\sim}200{\mu}g/mL$로 조절하여 DPPH radical 소거 효과를 측정한 결과 열수와 50% 에탄올 추출물의 비조사구 0 kGy와 조사구 10 kGy $50{\sim}200{\mu}g/mL$ phenolic 농도 전 구간에서 84.04~100.00%의 매우 높은 소거효과를 나타내었으나, 감마선 조사 처리에 따른 유의적인 차이는 없었다. ABTS radical 소거 활성 측정 결과 열수와 50% 에탄올 추출물의 비조사구 0 kGy와 조사구 10 kGy $200{\mu}g/mL$ phenolic 농도에서 95% 이상의 높은 소거 효과를 나타내었다. Antioxidant protection factor(PF) 측정 결과 $100{\mu}g/mL$ phenolic 농도 처리 시 열수 추출물 비조사구 0 kGy와 조사구 10 kGy에서 각각 2.51 PF, 2.01 PF, 50% 에탄올 추출물 비조사구 0 kGy와 조사구 10 kGy는 각각 1.38 PF, 1.48 PF를 나타내었다. TBARs 저해 효과는 $50{\sim}200{\mu}g/mL$ phenolic 농도 전 구간에서 열수 추출물 비조사구 0 kGy와 조사구 10 kGy에서 65.23~83.10%를 나타냈으며, 50% 에탄올 추출물 비조사구 0 kGy와 조사구 10 kGy에서 70.67~95.81%로 농도 의존적으로 증가하는 양상을 나타냈다. 본 연구 결과 감마선 조사 처리에 따른 total phenolic compounds 함량은 열수 추출물의 경우 조사 처리 후 함량이 감소하였고, 50% 에탄올 추출물의 경우 조사 처리 후 함량이 증가하는 것을 확인할 수 있었다. 독활의 장기저장을 위해 처리한 감마선 조사 전과 후 독활 추출물의 항산화 활성 변화에는 큰 영향을 주지 않는 것으로 보이며 이는 감마선 조사법이 독활을 포함한 한약재의 장기저장을 위한 처리법으로 유용하게 이용될 수 있을 것으로 판단된다.

• Journal of the Korean Wood Science and Technology
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• 제37권4호
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• pp.388-396
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• 2009

본 연구에서는 두부비지 가수분해물과 페놀수지로 조제된 마루판 화장용 접착제의 접착성능을 확인하기 위하여 수행하였다. 먼저 두부비지를 황산과 수산화나트륨으로 화학적으로 개량한 후 가교제로 phenol formaldehyde (PF) prepolymer와 혼합하여 접착제를 조제하였는데, 이 접착제는 고형분 함량을 기준으로 35%의 황산 가수분해물(AC), 35%의 수산화나트륨 가수분해물(AK) 그리고 30%의 PF로 조제하였다. 이렇게 조제된 접착제를 고밀도섬유판에 $300g/m^2$의 비율로 도포한 후 참나무 무늬목을 접착시켜 $7kg/m^2$의 압력으로 $120^{\circ}C$에서 열압하여 마루판을 제조하였다. 제조된 마루판에 대하여 formaldehyde/phenol 몰비(1.8, 2.1, 2.4), 퇴적시간(0분, 10분, 20분), 열압시간(90초, 120초)이 평면인장강도, 준내수 박리율, 포름알데히드 방산량에 미치는 영향에 대해 조사하였다. 두부비지 접착제를 이용하여 제조된 목질마루판의 평면인장강도는 KS 규격의 최소값을 상회하였으며, 대부분의 포름알데히드 방산량 값은 KS 규격의 E0 기준에 근접하는 것으로 나타났다. 따라서 두부비지 접착제가 마루판 화장용 접착제로 사용될 수 있다는 가능성을 보여 주었으나, 상용화를 위하여 내수성의 향상과 포름알데히드 방산량의 저감을 위한 연구가 필요할 것으로 생각한다.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• 제25권4호
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• pp.217-223
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• 2014

Objectives : This study was conducted in order to investigate the influence of sexual trauma on the psychopathology and quality of life of children and adolescents in Korea. Methods : Twenty-seven children and adolescents and their caretakers who visited the Kangwon Sunflower Center participated in a cross-sectional study. Participants completed the Korean version of Kiddie-Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version, Child Behavior Checklist (CBCL), and Child Health Questionnaire-Parent Form-50 (CHQ-PF-50). Their scores were compared with those of a age and sex-matched control group of 27 healthy children and adolescents. Results : Victims of sexual violence showed higher t score in Withdrawn, Social problems, Delinquent behavior, Externalizing problems, and Total problems in CBCL, compared with control group. In CHQ-PF-50, there were lower scores on Bodily pain/discomfort, Behavior, Mental health, Time impact in parents, and Family activities subscales in victims of sexual violence. While Behavior and Family activities subscale showed negative correlations with Delinquent behavior, Externalizing problems, and Total problems in CBCL. Mental health subscale showed negative correlations with Social problems, Delinquent behavior, Externalizing problems, and Total problems. In addition, Time impact on parent subscale showed a negative association with Delinquent behavior in CBCL. Conclusion : The current study provided evidence suggesting that victims of sexual violence had a higher level of psychopathology and lower level of quality of life.

• 한국식품영양과학회지
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• 제19권1호
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• pp.80-86
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• 1990

This experiment was conducted to study the effects of dietary zinc and ethanol on the zinc content of serum and tissues. Eight male rats of Sprague-Dawley strain with average weight of 80$\pm$5g were divided into five groups such as C group: ad libitum control diet(100 ppm Zn) plus isocaloric sucrose solution CE group ; ad libitum control diet plus 25% ethanol solution PF group ; pair fed control to zinc deficient diet(5ppm Zn) plus isocaloric sucrose solution ZD grop ; ad libitum zinc deficient diet plus isocaloric sucrose solution and ZDE group ; ad libitum zinc deficient diet plus 25% ethanol solution. The rats were sacrificed after 4 and 7 weeks of feeding periods. The liver weights of ZD and ZDF groups were increased however the weight of testis was decreased in the same groups The content of serum zinc was infiuenced by the dietary zinc level and the amount was significantly decreased in the ZD group. The content of liver zinc was influnced by the dietary zinc level and the amount was decreased by ethanol feeding. The content of testis zinc was significantly low in the ZDE group. The zinc level of feces to be increased by the ethanol feeding.

• 대한한방내과학회지
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• 제39권4호
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• pp.592-604
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• 2018

Objectives: This study is to review the effect of Korean medicinal herbs on treatment of benign prostatic hyperplasia induced in rat models, as reported in domestic and foreign journals. Methods: Six electronic databases (EMBASE, PubMed, Oasis, RISS, CENTRAL, and Koreankt) were searched with terms including benign prostatic hyperplasia to identify study reports on treatment of benign prostatic hyperplasia impairment with Korean medicinal herbs. After selecting several studies, the analysis focused on items reflected in the diagnosis of benign prostatic hyperplasia, such as prostate weight, thickness of the prostate epithelium, and prostate specific antigen. Results: Six studies were reviewed. Testosterone propionate was used as a benign prostatic hyperplasia induction material in all the included studies. Cinnamomum verum (CV), Cynanchum wilfordii (CW), Ponciri fructus (PF), Quisqualis indica (QI), Acorus gramineus (AG), and Melandrium firmum (MF) had reduced prostate weight statistically significantly. The QI gave a better response than finasteride in terms of reducing epithelium thickness, and the response was statistically significant. The prostate specific antigen level was lower in the group treated with CV than in the control group. Conclusions: CV, CW, PF, QI, AG, and MF had distinct therapeutic effects. However it is difficult to determine which of these is better by comparing them numerically because the observation items evaluated in a rat model of benign prostatic hyperplasia.