• 한국항공우주학회지
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• 제43권5호
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• pp.440-448
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• 2015

운동에너지 막대 탄두 시스템은 기존 시스템의 장점을 결합한 새로운 형태의 요격탄두 시스템으로서 직격 파괴방식에 비해 표적 유도 정밀도에 대한 의존도가 낮을뿐더러, 고폭 파편 탄두 방식보다 더 높은 관통력을 제공해 준다는 장점이 있다. 본 논문에서는 다양한 운동에너지 탄두의 사출 방식 중 등방성운동에너지 탄두의 기폭, 전개모델을 소개하고, TATE 관통방정식을 이용하여 사출된 관통자의 관통 효과를 계산하였다. 또한 교전 성능 분석을 위한 방법을 제시하였으며, 다양한 교전 상황에 대한 몬테-칼로 시뮬레이션을 통해 최적의 교전 기하 및 기폭 시점을 도출하였다.

• 한국추진공학회지
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• 제19권1호
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• pp.33-41
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• 2015

DSC 실험 데이터를 이용하여 고에너지 물질의 반응속도식을 추출해내는 이론적 방법을 제안하고 알루미늄 고함유 화약(RDX/HTPB/Al)에 대한 반응속도식 추출을 수행하였다. DSC 실험 결과는 Friedman 등전환법으로 분석되며 AKTS software를 사용하였다. 질량분율에 따른 활성화에너지와 빈도인자를 추출해 내어 반응속도식을 완성하였다. 추출된 반응속도식은 기존의 ODTX 실험을 통해 추출되는 화학반응속도식 형태에 비해 이론적 측면과 정확성 측면에서 상당한 장점을 갖는다. 추출된 반응속도식의 검증을 위해 화학반응률 그리고 생성물 질량분율에 대해 DSC 실험과 동일한 조건하에서 전산모사를 수행하였으며 실험값과 잘 일치함을 확인하였다. 또한 붕소 질산칼륨($B/KNO_3$)에 대한 완속가열 전산모사를 수행하였으며 실험결과와 비교하여 DSC 반응속도식의 전산모사에의 적용가능성을 확인하였다.

• The Journal of Korean Physical Therapy
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• 제16권3호
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• pp.192-204
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• 2004

The surface electromyographic(sEMG) analyses were knee joint angle during open kinetic chain exercise (OKC) and close kinetic chain exercise (CKC) in vastus medialis (VM), vastus lateralis (VL), and rectus femoralis (RF). Ten subjects with normal , aged 20 to 30(X=27.4, SD=3.23), were randomized Statistical techniques for data analysis were applied paired t-test. The 0.05 level of significane was used as the critical level for rejection of the null hypotheses for the study. And the results were: 1) Both OKC and CKC improved the strength of quadriceps muscle as the knee joint flexion was increased. 2) In OKC, the strength of VM was improved the most at the 30 degree angle. 3) In CKC, the strength of VM was improved the most at the 30 degree angle. 4) The VM/VL ratio was the largest at the 10 and 20 degree angles in OKC and CKC. 5) The VM/VL ratio at 10, 20, and 30 degree angles was significantly different between OKC and CKC (P < 0.05). Base on the results, the OKCE is recommended for the knee joint patients, especially for the patellofemoral pain syndrome patients, during the early phase of rehabilitation. In order to improve strength of the quadriceps, muscle strength training at 30 degree angle is recommended. In order to improve VM/VL ratio, 10 and 20 degree angles are recommended during OKCE and CKCE, respectively. Future researches are warranted comparing electromyographic analysis between OKCE and CKCE in the quadriceps at a certain work lead, and muscle strength performance in the quadriceps at different positions of foot.

• 분석과학
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• 제23권6호
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• pp.518-523
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• 2010

본 논문에서는 반응속도론적 인광 분석기(Kinetic Phosphorescence Analyzer, KPA)를 이 용하여 환경 시료 중의 우라늄 동위원소 분석에 대한 연구를 기술하였다. 극초단파 산분해 기술을 이용하여 토양 및 유리 재질 시료로부터 우라늄 성분을 추출한 후, UTEVA 수지를 통해서 우라늄 동위원소를 순수하게 분리하였고 KPA로 우라늄 농도를 정량하였다. 우라늄 표준용액을 사용하여 KPA를 이용한 우라늄 측정법에 대한 선형성 및 재현성 실험을 수행하였다. 우라늄 표준용액, 지하수 및 인증 표준시료에 대해 KPA를 사용하여 우라늄 농도를 측정하여 KPA를 이용한 우라늄 분석법에 대한 신뢰도를 검증하였다.

• 품질경영학회지
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• 제48권1호
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• pp.13-27
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• 2020

Purpose: The purpose of this study is to present a recoil measurement and analysis of K2 rifle for the development of a virtual reality marksmanship training in the Republic of Korea Army. Methods: For the recoil measurement, a test-bed is built by a barrel that has exact dimensions of K2 rifle and three piezoelectric pressure sensors mounted on the barrel. Data of over 200 rounds of 5.56mm M193 and K100 bullets are collected and analyzed from live fire experiments. For the recoil analysis, both the free recoil method and the gas exhaust aftereffect method are used to calculate a recoil velocity, momentum and kinetic energy of K2 rifle by applying the law of conservation of momentum. In addition, a new method is proposed that uses the third law of motion and the chamber pressure model for the recoil measurement Results: The results show how different between the previous and proposed methods with respect to M193 and K100 bullets of K2 rifle. In M193, the free recoil method demonstrates 1.113, 4.197, and 2.335, the gas exhaust aftereffect method computes 1.698, 6.407, and 5.441, and the proposed method calculates 0.990, 3.734, and 1.848 in recoil velocity, momentum and kinetic energy, respectively. In K100, the free recoil method demonstrates 1.190, 4.487, and 2.669, the gas exhaust aftereffect method computes 1.776, 6.699, and 5.949, and the proposed method calculates 1.060, 3.998, and 2.119 in recoil velocity, momentum and kinetic energy, respectively. Conclusion: This study implements live fire experiments to provide recoil velocity, momentum, and kinetic energy of K2 rifle using both M193 and K100 bullets. For the development of the army virtual reality marksmanship, the results in this paper would be useful to design and produce a gun and/or a rifle of virtual reality.

• 한국연소학회지
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• 제19권1호
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• pp.17-28
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• 2014

In this study, the laminar burning velocity of syngas fuel($H_2/CO$) and flame structure with various hydrogen contents were studied using both experimental measurements and detailed kinetic analysis. The laminar burning velocities were measured by the angle method of Bunsen flame configuration and the numerical calculations including chemical kinetic analysis were made using CHEMKIN Package with USC-Mech II. A wide range of syngas mixture compositions such as $H_2$ : CO = 10 : 90, 25 : 75, 50 : 50, 75:25 and equivalence ratios from lean condition of 0.5 to rich condition of 5.0 have been considered. The experimental results of burning velocity were in good agreement with previous other research data and numerical simulation. Also, it was shown that the experimental measurements of laminar burning velocity linearly increased with the increment of $H_2$ content although the burning velocity of hydrogen is faster than the carbon monoxide above 10 times. This phenomenon is attributed to the rapid production of hydrogen related radicals such as H radical at the early stage of combustion, which is confirmed the linear increase of radical concentrations on kinetic analysis. Particular concerns in this study are the characteristics of burning velocity and flame structure different from lean condition for rich condition. The decrease of OH radicals and double peaks are observed with $H_2$ content in rich condition once $H_2$ fraction exceeds over threshold.

• 한국전문물리치료학회지
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• 제28권3호
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• pp.208-214
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• 2021

Background: The CKCUES test evaluates the functional performance of the shoulder joint. The CKCUES test scores CKC exercises of the upper limbs to examine shoulder stability. Although the CKCUES test provides quantitative data on functional ability and performance, no study has determined the relationship between CKCUES scores and SA and TB muscle strength. Objects: The objective of this study is to determine the relationship between the CKCUES test scores and the strength of the SA and TB muscles in the CKCUES and unilateral CKCUES tests. Methods: Sixty-six healthy male volunteers participated in the study. A Smart KEMA strength sensor measured SA and TB muscle strength. Two parallel lines on the floor indicated the initial hand placement to start CKCUES tests. For 15 seconds, the subject raises one hand and reaches over to touch the supporting hand, then returns to the starting position. Results: The correlation between the CKCUES test scores and the strength of the SA was strong (r = 0.650, p < 0.001), and the TB was moderate (r = 0.438, p < 0.001). The correlation between the unilateral CKCUES test and the strength of the SA of the supporting side was strong (r = 0.605, p < 0.001), and swing side was strong (r = 0.681, p < 0.001). The correlation between the unilateral CKCUES test and the strength of the TB of the supporting side was moderate (r = 0.409, p < 0.001), and swing side was moderate (r = 0.482, p < 0.001). Conclusion: Our study showed that the CKCUES test had a strong association with isometric strength of SA and moderate association with that of TB. These findings suggest that the CKCUES test can evaluate the function of the SA. Moreover, the unilateral CKCUES test can evaluate unilateral shoulder function.

• 한국식품저장유통학회지
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• 제30권4호
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• pp.573-588
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• 2023

The purpose of this study was to monitor changes in the quality of ginseng and predict its shelf-life. As the storage period of ginseng increased, some quality indicators, such as water-soluble pectin (WSP), CDTA-soluble pectin (CSP), cellulose, weight loss, and microbial growth increased, while others (Na₂CO₃-soluble pectin/NSP, hemicellulose, starch, and firmness) decreased. Principal component analysis (PCA) was performed using the quality attribute data and the principal component 1 (PC1) scores extracted from the PCA results were applied to the multivariate analysis. The reaction rate at different temperatures and the temperature dependence of the reaction rate were determined using kinetic and Arrhenius models, respectively. Among the kinetic models, zeroth-order models with cellulose and a PC1 score provided an adequate fit for reaction rate estimation. Hence, the prediction model was constructed by applying the cellulose and PC1 scores to the zeroth-order kinetic and Arrhenius models. The prediction model with PC1 score showed higher R² values (0.877-0.919) than those of cellulose (0.797-0.863), indicating that multivariate analysis using PC1 score is more accurate for the shelf-life prediction of ginseng. The predicted shelf-life using the multivariate accelerated shelf-life test at 5, 20, and 35℃ was 40, 16, and 7 days, respectively.

• 대한물리의학회지
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• 제6권2호
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• pp.215-223
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• 2011

Purpose: The purpose of this study was to determine the effect of leg muscle activation by applying proprioceptive neuromuscular facilitation (PNF) arm patterns to unilateral upper extremities under the condition of both open and closed kinetic chains in a seated position. Methods: Twenty-two healthy subjects participated in this study. Four PNF patterns were applied to each subject's unilateral upper extremity. EMG data were collected from the vastus medialis, biceps femoris, tibialis anterior and gastrocnemius. The measured EMG data were digitized and processed to root mean square (RMS) and expressed as percentage maximal voluntary isometric contraction (%MVIC). The data were analyzed using two-way analysis of variance (ANOVA) with repeated measures to determine the statistical significance. Results: The results of this study were summarized as follows: Firstly, in comparison to muscle activation of the biceps femoris, there was a significant increase in the D2 flexion pattern when it was compared with D2 extension pattern and when it was compared with D1 flexion pattern (p<.05). Secondly, there was a significant increase in the muscle activation of the vastus medialis and tibialis anterior with a closed kinetic chain rather than an open kinetic chain (p<.05). Conclusion: In conclusion, in order to increase muscle activation of the biceps femoris, the D2 flexion pattern can be applied, regardless of kinetic chain. In addition, in order to increase muscle activation of the vastus medialis and tibialis anterior, four arm patterns can be applied with a closed kinetic chain.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2002년도 제25회 KOSCI SYMPOSIUM 논문집
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• pp.173-184
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• 2002

In order to evaluate the devolatilization models of pulverized coal, various devolatilization models are examined for the numerical analysis of Drop Tube Furnace.The results of analysis are compared with the experimental results. A numerical study was conducted to explore the sensitivities of the predictions to variation of the model parameters. It helps to elucidate the source of the discrepancies. Three different wall temperature conditions of the DTF, 1100, 1300 and $1500^{\circ}C$ were considered in this analysis. Two fuels are U.S.A. Alaska coal and Australia Drayton coal. The results of analysis with constant rate model, single kinetic rate model and two competing rate modes well presented fast volatile matter release in the early devolatilization. However, in the latter devolatilization they did not coincide with experimental results which presented tardy volatile matter release on account of pyrolysis of high molecular substance. On the other hand, the results of analysis with DAEM(Distribute Activation Energy Model) coincided with experiment al results in overall devolatilization.