• Title/Summary/Keyword: size-dependent

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Diopside DSD (crystal size distribution) in the Contact Metamorphic Aureole (Hwanggangni Formation) near the Daeyasan Granite Goesan, Korea (괴산지역 대야산 화강암체 주변 접촉변성대(황강리층)에서의 투휘석 결정 크기분포)

  • Kim, Sangmyung;Kim, Hyung-Shik
    • The Journal of the Petrological Society of Korea
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    • v.5 no.2
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    • pp.161-167
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    • 1996
  • The CSD (crystal size distribution) of diopside crystals in the calc-silicate hornfels of the Hwanggangni Formation intruded by the Cretaceous Daeyasan granite shows the patterns of continuous nucleation and growth. There is correlation between the distance from the intrusion contact and the slopes from the linear part of log(population density) vs. size diagrams. In the log(population density) vs. size diagrams of the samples systematically collected from the intrusion contact, two different groups are recognized; the slopes for the samples near the intrusion contact (horizontal distance from the contact less than 50m) are gentler (1500$cm^{-1}$) than those for the samples away from the intrusion contact (2500$cm^{-1}$, distance from the contact greater than 100 m). These differences may reflect the differences in growth rates and crystallization time, or the differences in diopside-forming reactions. All of the log(population density) vs. size diagrams show depletion of smaller crystals. The observed depletion may be due to Ostwald ripening or the changes in nucleation rates as the reactant phases diminishes. Similar grouping is also possible for the observed degree of depletion of smaller crystals; the depletion decreases with increasing distance from the intrusion contact, suggesting temperature-dependent rates of Ostwald ripening.

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An Experimental Study on Angled Injection and Droplet Size Characteristics of Liquid Jets in Subsonic Crossflow

  • Kim, Min-Ki;Song, Jin-Kwan;Hwang, Jeong-Jae;Yoon, Young-Bin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.03a
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    • pp.486-491
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    • 2008
  • The spray characteristics and drop size measurements have been experimentally studied in liquid jets injected into subsonic crossflow. With water as fuel injection velocity, injection angle and atomizer internal flows were varied to provide of jet operation conditions. The injector internal flow was classified as three modes such as a non-cavitation flow, cavitation, and hydraulic flip flows. Pulsed Shadowgraph Photography measurement was used to determine the spatial distribution of the spray droplet diameter in a subsonic crossflow of air. And this study also obtains the SMD(Sauter Mean Diameters) distribution by using PLLIF(Planar Liquid Laser Induced Fluorescence) technique. The objectives of this research are getting a droplet distribution and drop size measurement of each condition and compare with the other flows effect. As the result, This research have been showed the droplet size were spatially dependent on air-stream velocity, fuel injection velocity, injection angle effects and normalized distance from the injector exit length.(x/d, y/d)There are also different droplet size characteristics between cavitation, hydraulic flip and the non-cavitation flows.

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Chip Size-Dependent Light Extraction Efficiency for Blue Micro-LEDs (청색 마이크로 LED의 광 추출 효율에 미치는 칩 크기 의존성 연구)

  • Park, Hyun Jung;Cha, Yu-Jung;Kwak, Joon Seop
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.32 no.1
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    • pp.47-52
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    • 2019
  • Micro-LEDs show lower efficiencies compared to general LEDs having large areas. Simulations were carried out using ray-tracing software to investigate the change in light extraction efficiency and light distribution according to chip-size of blue flip-chip micro-LEDs (FC ${\mu}-LEDs$). After fixing the height of the square FC ${\mu}-LED$ chip at $158{\mu}m$, the length of one side was varied, with dimensions of 2, 5, 10, 30, 50, 100, 300, and $500{\mu}m$. The highest light-extraction efficiency was obtained at $10{\mu}m$, beyond which the efficiency decreased as the chip-size increased. The chip size-dependence of the FC ${\mu}-LEDs$ both without the patterned sapphire substrate, as well as vertical FC ${\mu}-LEDs$, were analyzed.

A damage model predicting moderate temperature and size effects on concrete in compression

  • Hassine, Wiem Ben;Loukil, Marwa;Limam, Oualid
    • Computers and Concrete
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    • v.23 no.5
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    • pp.321-327
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    • 2019
  • Experimental isotherm compressive tests show that concrete behaviour is dependent on temperature. The aim of such tests is to reproduce how concrete will behave under environmental changes within a moderate range of temperature. In this paper, a novel constitutive elastic damage behaviour law is proposed based on a free energy with an apparent damage depending on temperature. The proposed constitutive behaviour leads to classical theory of thermo-elasticity at small strains. Fixed elastic mechanical characteristics and fixed evolution law of damage independent of temperature and the material volume element size are considered. This approach is applied to compressive tests. The model predicts compressive strength and secant modulus of elasticity decrease as temperature increases. A power scaling law is assumed for specific entropy as function of the specimen size which leads to a volume size effect on the stress-strain compressive behaviour. The proposed model reproduces theoretical and experimental results from literature for tempertaures ranging between $20^{\circ}C$ and $70^{\circ}C$. The effect of the difference in the coefficient of thermal expansion between the mortar and coarse aggregates is also considered which gives a better agreement with FIB recommendations. It is shown that this effect is of a second order in the considered moderate range of temperature.

Effect of Austenite Grain Size on Ms temperature of γ→ε Martensitic Transformation in an Fe-Mn Alloy (Fe-Mn 합금에서 γ→ε 마르텐사이트 변태의 Ms 온도에 미치는 오스테나이트 결정립크기의 영향)

  • Jun, Joong-Hwan;Choi, Chong-Sool
    • Journal of the Korean Society for Heat Treatment
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    • v.10 no.2
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    • pp.93-100
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    • 1997
  • Effect of austenite grain size on starting temperature of ${\gamma}{\rightarrow}{\varepsilon}$ martensitic transformation($M_s$) has been studied in an Fe-18%Mn alloy. Particular attention was paid on the variation of stacking fault energy with austenite grain size, which is considered to be a important factor affecting ${\gamma}{\rightarrow}{\varepsilon}$ martensitic transformation. Austenite grain size was increased in a wide range from $13{\mu}m$ to $185{\mu}m$ with increasing solution treatment temperature from $700^{\circ}C$ to $1100^{\circ}C$. Hardness was decreased with increasing austenite grain size while the volume fraction of ${\varepsilon}$ martensite showed a reverse tendency, which indicates that the hardness is more dependent on austenite grain size than ${\varepsilon}$ martensite content. No significant change was found in $M_s$ temperature when the grain size was larger than about $30{\mu}m$. In case that, the austenite grain size was smaller than about $30{\mu}m$, however, $M_s$ temperature was marlkedly decreased with decreasing austenite grain size. A linear relationship between $M_s$ temperature and the stacking fault formation probability, i.e. the reciprocal of the stacking fault energy was obtained, which suggests that the variation of $M_s$ temperature with austenite grain size is closely related to the change in stacking fault energy.

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The Effect of Manual Physical Therapy on Improvement in the Range of Motion of Frozen Shoulder Patients: A Meta-Analysis of Cases in South Korea

  • Kim, Chan Myeong;Lee, Jong Kyung;Hwang, Jong Ha;Lee, Jae Kwang
    • The Journal of Korean Physical Therapy
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    • v.33 no.5
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    • pp.211-216
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    • 2021
  • Purpose: The main purpose of this meta-analysis was to identify the degree of effect size and variables for the impact of manual physical therapy on the improvement in the range of motion of frozen shoulder patients. Methods: This study collected 8 studies published between 1st January 2010 and 31st December 2020. The analysis of the results verified 49 effect size data and the random effect model was chosen. Results: First, the full case showed the largest mean effect size of 2.485 (p<0.001). Second, the size of the effect based on manual therapy and modality therapy showed an effect size of 4.178 (p<0.001). Third, the outcome group included 6 variables. The external rotation (2.818) variable group showed the largest mean effect size, followed by internal rotation (2.748), flexion (2.643), abduction (2.356), and adduction (2.356). Six outcomes were significant and the mean effect sizes of all the varied groups were above large size. The number of participants showed a 20 or less effect size of 2.478 (p>0.737). The number of intervention periods showed 4 weeks 20 or more effect size of 2.782 (p>0.294). Finally, the 'Trim and Fill' result confirmed that the calibration effect size was 1.471 (p<0.001). Conclusion: This study verified that manual physical therapy had a substantial effect on the improvement of the range of motion of patients with frozen shoulders and that the effects were dependent on the methods of outcomes.

Simulation analysis of type I error and power for F test and rank transformed F test in $2 times 2$ factorial ANOVA ($2 times 2$ 요인 계획법의 F 검정과 순위 F 검정에 따른 제1종 오류와 검정력 분석에 대한 의태 연구)

  • 최영훈
    • The Korean Journal of Applied Statistics
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    • v.8 no.2
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    • pp.87-97
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    • 1995
  • When there is no main effcts or only one main effect in a $2 \times 2$ factorial design, Type I error rates and power for the rank transformed F test (FR test) for interaction are nearly equal to those of the classical F test. However the power of FR test is quite superior under the exponential distribution rather than the of FR test is quite superior under the exponential distribution rather than the normal distribution. Meanwhile when both main effects are in the model, Type I error rates of FR test, compared with those of F test, decrease as the effect size increases and are dependent on the fashion in which main effects are constructed. In addition, the power of FR test increases as the effect size and the sample size increase and is highly dependent on the manner in which main effects are constructed and the type of population distribution.

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Optical Properties of Self-assembled InAs Quantum Dots with Bimodal Site Distribution (이중 크기분포를 가지는 자발형성 InAs 양자점의 광특성 평가)

  • Jung, S.I.;Yeo, H.Y.;Yun, I.;Han, I.K.;Lee, J.I.
    • Journal of the Korean Vacuum Society
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    • v.15 no.3
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    • pp.308-313
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    • 2006
  • We report a photoluminescence (PL) study on the growth process of self-assembled InAs quantum dots (QDs) under the various growth conditions. Distinctive double-peak feature was observed in the PL spectra of the QD samples grown at the relatively high substrate temperature. From the excitation power-dependent PL and the temperature-dependent PL measurements, the double-peak feature is associated with the ground state transitions from InAs QDs with two different size branches. In addition, the variation in the bimodal size distribution of the QD ensembles with different InAs coverage is demonstrated.

A Meta Analysis of Group Music Therapy with Adolescents (청소년 대상 그룹 음악치료 효과에 대한 메타분석)

  • Hwang, Eun-Young
    • Journal of Music and Human Behavior
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    • v.9 no.2
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    • pp.1-17
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    • 2012
  • The purpose of this study was to analyze data regarding the effects of group music therapy with adolescents. 27 master's, doctorial theses and published articles between 2000 and 2012 were selected for meta analysis. Subjects, independent variables, dependent variables, and the number of session were used to compare the effectiveness of group music therapy program. 49 effect sizes using means and standard deviation from 27 studies were calculated. The results were as follows. The overall mean effect size was -0.14, which is small size effect, according to Cohen's ES interpretation criteria. The mean ES was influenced by the subjects(adolescents/maladjustment students/addictive students/students in facility), the ES of adolescents was the biggest. However there were no significant difference among subjects. During the independent variables(active music therapy/receptive music therapy/combined music therapy), combined music therapy showed the biggest efficacy. When results were sorted by the dependent variables (social/emotional/behavior/cognitive category), the ES of behavioral category was the biggest. However, there was no significant difference among them. The ES of 11~15 session was the most effective.

Fault Coverage Metric for Delay Fault Testing (지연 고장 테스팅에 대한 고장 검출율 메트릭)

  • Kim, Myeong-Gyun;Gang, Seong-Ho;Han, Chang-Ho;Min, Hyeong-Bok
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.38 no.4
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    • pp.266-276
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    • 2001
  • Due to the rapid development of semiconductor technology, the complexity of VLSI circuits has heavily increased. With the increased densities of integrated circuits, several different types of faults can occur Thus, testing such circuits is becoming a sever problem. Delay testing can detect system timing failures caused by delay faults. However, the conventional delay fault coverage in terms of the number of detected faults may not be an effective measure of delay testing because, unlike a stuck-at-faults, the impact of a delay fault is dependent on its delay defect size rather than on its existence. Thus, the effectiveness of delay testing is dependent on the propagation delay of the path to be tested, the delay defect size, and the system clock interval. This paper proposes a new delay defect fault coverage that considers both propagation delay of the path to be tested and additional delay defect size. And the relationship between delay defect fault coverage and defect level is analyzed.

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