Background: Various functional tests such as upper quarter Y-balance test (UQYBT) are used to evaluate shoulder stability and mobility in clinical or sports fields. Previous studies have been conducted to determine the correlation between the scapular or trunk muscle and UQYBT. However, the correlation between UQYBT and hip flexor, which can be considered as a core muscle, has not been confirmed. Objects: To verify the relationship between the UQYBT and scapular muscle (scapular protractor and lower trapezius [LT]), trunk muscle, and hip flexor strengths in healthy male participants. Methods: A total of 37 healthy male participants were recruited and underwent UQYBT in the push-up posture. The isometric strength of the scapular protractor, LT, trunk flexor and extensor, and hip flexors were measured using a smart KEMA strength sensor (KOREATECH Inc.). Results: The superolateral direction of the UQYBT was moderately to strongly related to trunk extensor (r = 0.443, p < 0.01), scapular protractor (r = 0.412, p < 0.05), LT (r = 0.436, p < 0.01), and both sides of the hip flexors (supporting-side: r = 0.669, p < 0.01; non-supporting- side: r = 0.641, p < 0.01). The inferolateral direction of the UQYBT was moderately related to the scapular protractor (r = 0.429, p < 0.01), LT (r = 0.511, p < 0.01), and both sides of hip flexors (supporting-side: r = 0.481, p < 0.01; non-supporting-side: r = 0.521, p < 0.01). The medial direction of the UQYBT was moderately to strongly related with the scapular protractor (r = 0.522, p < 0.01), LT (r = 0.541, p < 0.01), and both sides of hip flexors (supporting-side: r = 0.605, p < 0.01; non-supporting-side: r = 0.561, p < 0.01). Conclusion: This study showed that the strength of the scapular muscles, trunk muscles, and hip flexor muscles correlated to the UQYBT. Therefore, the strength of not only the scapular and trunk muscles but also the hip flexor muscles should be considered to improve the UQYBT.

Background: The elderly population is increasing rapidly worldwide. Muscle mass, usual walking speed (UWS), knee extension strength (KES), hand grip strength (HGS), peak expiratory flow (PEF), and depression is used for sarcopenia diagnosis. All four of these factors (KES, HGS, PEF, and depression) correlated with UWS and also to muscle mass. But, many studies have suggested that no correlation exists between muscle mass and UWS. Objects: This study aimed: 1) to investigate whether muscle mass reduction affected UWS, as mediated by KES, HGS, PEF and depression, and 2) to explored whether significant changes in these mediators varied by the body segment in which muscle mass evaluated in elderly female aged 65–80 years. Methods: A total of 100 female aged 65–80 years were surveyed. Muscle mass was measured by body segment (upper and lower segment), and KES, HGS, PEF, depression, and UWS were also assessed. Median analyses were progressed in IBM SPSS software (ver. 23.0, IBM Co.) using a downloaded INDIRECT macro. Results: The direct effect of the KES and PEF were significant, and the indirect effect of KES and PEF were not significant. Thus, KES and PEF served as full mediators of the effect of muscle mass on UWS. Regardless of bodily region, KES and PEF combined with muscle mass were significant mediators of UWS, with similar indirect effect sizes. Conclusion: KES and PEF are the only mediators regardless of body part. Therefore, mediating the KES and PEF may prevent sarcopenia progression in elderly female. Also, sarcopenia can be readily assessed by evaluating either the upper or lower body; it is not necessary to measure total muscle mass.

Background: Falls are a common and serious problem in the elderly population. Muscle strength and balance are important factors in the prevention of falls. The Y-balance test (YBT) is used to assess dynamic postural control and shows excellent test-retest reliability. However, no studies have examined the relationship between lower-limb strength and YBT scores in elderly women. Objects: This study aimed to examine the relationship between lower-limb strength and YBT scores in elderly women. Methods: Thirty community-dwelling elderly women participated in the study. Lower-limb strength including hip flexor, hip extensor, hip abductor (HAB), hip adductor (HAD), knee flexor, knee extensor, ankle dorsiflexor, and ankle plantar flexor (PF) muscles was examined using a smart KEMA strength sensor (KOREATECH Inc.), and the YBT was used to assess dynamic balance. Relationship between lower-limb strength and YBT was demonstrated using a Pearson’s correlation coefficient. Results: HAB strength (r = 0.388, p < 0.05), HAD strength (r = 0.362, p < 0.05), and ankle PF strength (r = 0.391, p < 0.05) positively correlated with the YBT-anterior direction distance. Ankle PF strength was positively correlated with the YBT-posteromedial direction distance (r = 0.396, p < 0.05) and composite score (r = 0.376, p < 0.05). Conclusion: The results of this study suggest that HAB, HAD, and ankle PF strengths should be considered for dynamic postural control in elderly women.

The carbon-containing molecule can be used as an NMR probe to explore the acidic and structural features of various catalytic materials. Thereinto, although mesityl oxide (MO) has been extensively employed to determine the acidity of solution and ionic liquid systems, could it be utilized to characterize the acidic properties of solid acid catalysts? In this work, on the basis of a series of isolated Brønsted and Lewis acid models with varied acid strengths, the adsorption configurations and corresponding 13C chemical shifts of adsorbed MO molecules have been comprehensively studied by means of a theoretical investigation approach. Among them, both the 13C chemical shift difference between β and α carbon atoms (Δδ), and the 13C chemical shift of β carbon atoms (δ13Cβ) in adsorbed MO molecules were explicitly demonstrated to be closely related to the intrinsic acid strength of Brønsted acid sites. These correlations could be utilized to quantitatively scale the Brønsted acid strength of solid acid catalysts. Besides, a moderate relationship was theoretically derived for the relevant 13C NMR parameters and intrinsic Lewis acid strength.

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.

Background: The hip muscle plays various roles. Several types of functional performance tests are used for the assessment of patients with various lower extremity injuries. Hip muscle functions are important to test the performance of maintaining the spine, pelvic, and leg during bridging exercise. We designed a novel functional performance test tool, which we named close kinetic chain dynamic lower extremity stability (CKCLE) test to assess hip muscle functions. Objects: The purpose of this study was to determine the relationship between CKCLE test and hip extensor, external rotator, and abductor strengths. Methods: Twenty-two subjects were recruited in the present study (13 males and 9 females). The hip extensor, external rotator, and abductor muscle strengths were measured using a Smart KEMA strength sensor. When the examiner said “Go”, the subject performed the CKCLE test by moving one leg from the floor and touching the opposite knee and then return to the floor while maintaining the bridging position. The subjects attempted as many “touches” as possible in the allotted time (20 seconds) during the maximal tests. The correlation between the hip muscle (extensor, external rotator, and abductor) strength of the supporting leg and the number of CKCLE tests performed in 20 seconds was determined using the Pearson correlation. Results: Hip extensor (r = 0.626, p < 0.05), hip external rotator (r = 0.616, p < 0.05), and hip abductor muscle strengths (r = 0.475, p < 0.05) positively correlated with the number of CKCLE tests performed. Conclusion: We designed a CKCLE test and found that performance in the test correlated with hip extensor, external rotator, and abductor muscle strengths. The result suggests that the CKCLE test can be applied as a performance test to assess the functions of the hip extensor, external rotator, and hip abductor muscles.

Background: The wall squat exercise has been recommended for strengthening of the lower extremity muscles with maintaining lumbar lordosis. Although squat has been studied to be related to lower extremity extensor strength, the relationship between wall squat and lower extremity extensor strength unclear. Because squat and wall squat are biomechanically different, study on the relationship is needed. Objects: The purpose of this study was to determine the lower extremity extensor strength associated with wall squat performance. Methods: 74 healthy volunteers were recruited to participate in this study. The volunteers were measured hip and knee extensors strength and then performed wall squat exercise for maximum count. Results: We found significant relationships between wall squat performance and hip extensor strength normalized by body weight, knee extensor strength normalized by body weight and the composite value. In a regression analysis, hip extensor strength normalized by body weight explained 29% of the variation in wall squat performance in males and 35% in females. Conclusion: These results demonstrate that hip extensor strength normalized by body weight is critical to wall squat performance in both sexes.

More Roller-compacted concrete (RCC) is a dry concrete consisted of same materials as conventional concrete with different proportioning which requires compaction effort in order to reach its final form. Thus, both hydration and aggregate interlock play important roles in its strength augmentation. Flexural strength, an important factor in pavement design and fatigue cracking resistance, can be difficult to be obtained at in-situ and may be subjected to high variability. Even though its compressive strength is relatively high compared to conventional concrete with similar binder content, the relationship between compressive strength and flexural or tensile strength were not well defined. The goal of this research is to compare the relationship between compressive strength and flexural strength as well as the relationship between compressive strength and splitting tensile strength of RCC with those of conventional concrete using various equations suggested in other researches and also to determine new regression equations for estimating RCC’s flexural and splitting tensile strength. The positive result of RCC’s flexural strength was found; it was higher than majority of predicted values from conventional concrete for the same compressive strength. In contrast, RCC’s splitting tensile strength was relatively low compared to that of conventional concrete for the same compressive strength. Power equations were learned to be suitable for relationship between compressive and flexural strengths as well as relationship between compressive and splitting tensile strengths.

콘크리트에서 강도는 콘크리트의 물리적 특성을 평가할 수 있는 중요한 인자중 하나이며 압축강도의 경우 실험의 편리함과 범용성으로 인해 널리 사용되고 있다. 콘크리트는 재료와 양생조건 등에 따라 압축강도가 달라지며, 특히 동일 재료라 하더라고 양생조건에 따라 강도는 변한다. 그러므로 현장에서 시공한 콘크리트의 강도를 알기위해서는 현장과 동일한 양생조건에 놓여야만 정확하게 강도를 측정할 수 있다. 그러나 현실적으로 밤낮으로 변화하는 현장의 양생조건을 실내에서 묘사하기란 쉽지가 않다. 또한 실제 콘크리트 포장의 강도를 측정하기 위해 포장체에 코어를 뚫기 때문에 손상이 가해지는 걸 피할수는 없다. 이러한 한계를 극복하기 위해 이미 비파괴 기법에 대한 다양한 연구가 진행되어 왔으며 그중 탄성파를 이용해 이미 콘크리트의 압축강도와 탄성파 속도와의 상관관계가 높음이 입증되었다. 본 연구에서는 양생조건에 따른 압축강도와 전단파 속도의 상관성을 분석하기 위해 동일 시멘트 페이스트를 3가지 서로 다른 양생온도에서 재령별 압축강도와 탄성파 속도의 변화를 측정했으며, 이 두 변수간의 상관관계를 파악하였다. 그 결과 양생온도는 재령별 압축강도증진과 탄성파 속도증가에 각각 영향을 미치는 것으로 나타났으나, 압축강도와 전단파 속도와의 상관관계에는 영향을 미치지 않는 것으로 나타났다.

본 연구에서는 포장용 콘크리트의 강도실험을 통해 강도간의 상관관계식을 도출하는 것을 목적으로 하였다. 강도로서 재령별 압축강도, 휨강도, 할렬인장강도와 탄성계수를 측정하였다. 배합변수는 조골재(화강암, 석회암, 사암), 세골재(자연사, 세척사, 부순모래) 및 단위시멘트량(315-375kg)을 변수로 하였다. 전체적으로 골재나 단위시멘트량보다는 재령에 의해 전형적인 강도곡선을 따라 뚜렷하게 변화함을 보여준다. 이러한 강도결과를 바탕으로 휨강도와 압축강도, 할렬인장강도와 압축강도, 탄성계수와 압축강도, 할렬인장강도와 휨강도의 상관관계를 분석한 결과 휨강도와 압축강도, 탄성계수와 압축강도는 기존의 관례대로 제곱근(n=0.5)의 상관관계식이 잘 맞음을 알 수 있었다. 할렬인장강도와 휨강도는 선형의 상관관계식으로 표현하였고, 할렬인장강도와 압축강도는 n=0.87의 지수승을 사용한 경우가 가장 적합한 것으로 나타났다.

We have examined the relationship between the speeds of coronal mass ejections (CMEs) and the GOES X-ray peak fluxes of associated flares. Noting that previous studies were possibly affected by projection effects and random association effects, we have considered two sets of carefully selected CME-flare events: four homologous events and four well-observed limb events. In the respective samples, good correlations are found between the CME speeds and the GOES X-ray peak fluxes of the associated flares. A similarly good correlation is found for all eight events of both samples when the CME speeds of the homologous events are corrected for projection effect. Our results suggest that a close relationship possibly exists between CME kinematics and flaring processes.

어군의 분포밀도와 초음파산란강도의 관계를 검토하기 위하여, 50kHz의 주파수에서 net cage (농망)에 분포밀도가 기지인 어군을 수용하고, 어군밀도의 변화에 기인하는 echo energy의 변동을 고찰하고, 또 cage 실험에 의해 추정한 어체의 평균적인 반사강도와 개개의 어체를 대상으로 구한 평균반사강도를 상호 비교, 검토한 결과를 요약하면 다음과 같다. 1. cage 실험에 의한 붕어의 평균반사강도는 -41.9dB로서, 이 값은 현장에서 개개의 붕어(마취어, 평균체장 19.1cm)를 대상으로 측정한 평균반사강도 -42.6dB보다 0.7dB 더 컸다. 2. cage내에 수용한 어군의 분포밀도가 증가함에 따라, 어군에 의한 평균체적산란강도는 직선적으로 증가하는 경향을 나타내었다. 즉, 어군밀도가 7, 13, 20, 26, 39, 52, 66 마리/m 상(3)였을 때, 각각의 어군에 의한 평균체적산란강도는 -33.0, -28.9, -27.6, -24.3, -25.1, -23.6, -22.1dB이었다. 3. 어군밀도 σ(마리/m 상(3))와 평균체적산란강도 (dB)와의 사이에는 다음의 관계식이 성립하였다. =-41.9+11.0 Log(σ), r=0.97 이 식에 회귀직선의 기울기 11은 이론적인 값 10에 거의 근사하였다.

이종재 마찰용접재 강도특성과 초음파 반사계수와의 상관성에 관하여 실험적으로 연구한 결과의 요약은 다음과 같다. 1. 이종재 마찰용접 이음면에서의 초음파 반사계수를 펄스반사법에 의하여 측정산출할 수 있다. 2. 5MHz의 비교적 낮은 주파수의 탐촉자를 사용하므로써 시험편의 표면가공 오차를 무시할 수 있다. 3. 알루미늄과 스테인레스의 마찰용접에서는 용접조건으로 마찰가열시간이나 가열압력을 변수로 하였을 때보다 업셋가압력을 변수로 하였을 때 반사계수의 변화가 뚜렷하다. 4. 업셋가압력을 변수로 한 용접조건과 반사계수사이에는 선형적 상관관계가 있다. 5. 용접이음면에서의 이음인장강도와 반사계수와의 상관관계식을 정량적으로 도출할 수 있다. 6. 초음파 반사계수에 의해 이종재 마찰용접 품질의 비파괴적 평가가 가능하다

본 연구에서는 20대 초반의 남, 여를 대상으로 초음파 방식으로 측정된 골밀도와 신체조성 및 배근력의 관계에 대해 알아보았다. D대학에 재학 중인 61명의 학생에 대해 IRB 승인과 참여자 동의 후 설문조사, 초 음파방식 골밀도 및 신체조성, 배근력을 측정하였다. 골밀도는 주로 사용하는 측 종골을 측정하여 T-값을 두 그룹(T-score≥-1.0; T-score＜-1.0)으로 나누었다. 생체전기 저항법을 이용하여 신체조성을 측정하였고, 배근력은 2회 측정하여 평균값을 구하였다. 모든 통계분석은 SPSS ver. 22.0 을 사용하여 실시하였다. 신체 활동 또는 체질량지수가 증가할수록 골밀도 및 신체조성의 근육량도 증가하였다. T-값이 높은 그룹이 낮은 그룹 보다 신체조성의 근육량 및 골격근량, 신체발달이 높았지만 통계학적인 유의성은 없었다(p>0.05). 배 근력에서도 T-값이 높은 그룹이 낮은 그룹 보다 높았다(101.1 vs. 92.1, p=0.308). 남, 여그룹에서 골밀도 T- 값과 신체조성의 골격근과 근육량은 보통 수준의 유의한 양의 상관성을 보였고(p<0.05), 배근력은 신체조성의 골격근과 근육량, 신체발달에서 골밀도 보다 높은 유의한 양의 상관성을 보였다(p<0.001). 여자그룹이 남자그룹 보다 골밀도 T-값과 신체조성의 골격근과 신체발달에서 높은 상관성을 보였다. 남자 그룹에서 배근력과 골밀도의 T-값과는 유의한 상관성을 보이지 않았지만(r=0.176, p=0.319), 여자 그룹에서는 보통 수준의 유의한 상관성을 보였다(r=0.591, p=0.001). 이상과 같이 초음파 방식으로 측정된 골밀도와 신체조성, 배 근력은 상호 유의한 관련성을 보였다.

화력발전의 부산물인 플라이 애쉬는 포졸란 반응을 통하여 조직구조를 개선하고 장기 강도 및 염화물 저항성에 매우 효과적이다. 본 연구에서는 28일 및 180일 재령의 보통 포틀랜트 시멘트 및 FA를 혼입한 콘크리트에 대하여 압축강도 및 염화물 저항성을 평가하였으며, 재 령의 증가에 따른 상관성을 평가하였다. 이를 위해, 물-결합재비(W/B)를 37%, 42%, 47%의 3가지 수준, Fly Ash를 시멘트 중량의 0%, 30%, 50%의 3가지 수준으로 나누어 총 9가지 배합을 설정하였으며, 28일 및 180일 재령 시, 압축강도, Tang‘s method에 의한 촉진확산계수, 그리고 ASTM C 1202, KS F 2711을 통한 통과전하량을 측정하였다. Fly Ash 혼입율이 클수록, W/B가 낮을수록 염화물 저항성(확산계수 및 통과전하 량)이 개선되었는데, 모든 FA 50 배합에서 염화물 저항성은 재령 28일 대비 재령 180일에서 약 15% 수준으로 감소하였다. 이는 FA의 포졸란 반응으로 인해 공극구조가 더 치밀해져 나타난 결과이며, 염해 저항성이 강도보다 시간에 더욱 의존적임을 알 수 있다. 재령 180일 이후, FA를 혼입한 배합에서 강도와 염해저항성의 뚜렷한 선형관계가 관측되었다.

The volume expansion of corroded steel reinforcement produces tensile stress on the surrounding concrete, which causes splitting cracking of concrete cover, and deteriorates the service ability and durability of reinforced concrete(RC) members. In addition, since the steel corrosion induces bond strength degradation between steel bar and concrete, the structural performance of RC members can be deteriorated significantly. In this study, the theoretical study was performed to probe the mechanism of the bond strength reduction due to steel corrosion. The bond strength between corroded steel bar and concrete was calculated by mathematically formulating the expansion pressure of corroded steel reinforcement. The proposed model was verified by comparing with the existing test results, and it showed that the proposed model estimate the bond strength reduction of corroded RC elements very closely.

본 연구는 건설적 실패 이론에 기초하여 스포츠 선수들이 내재하고 있는 실패내성의 개념적 구조를 확인하고, 실패내성의 정도가 훈련과 수행에 결정적인 정신력 요소와 어떤 관련이 있는지를 탐색하고자 하였다. 이를 위해 스포츠 상황을 반영한 실패내성 척도를 개발하고 437명의 개인, 단체종목 선수를 대상으로 내적 구조 타당성을 검토하였으며, 인내, 노력, 투지, 승부욕 등 정신력 요소와의 다차원적 관계를 검증하였다. 분석 결과, 스포츠 실패내성은 실패 후 행동, 감정, 과제난이도 선호의 3요인 구조로 나타나 학업 상황에서 일반화된 실패내성 이론모형을 지지했으며, 전반적으로 여자선수들이 남자선수들에 비해 실패내성이 강하고 학교 급이 낮은 중학생 선수들이 높은 실패내성을 보인다는 사실을 확인했다. 아울러, 실패내성의 하위 차원들 중 실패 후 행동과 과제난이도 선호 정도는 정신력 요소와 밀접한 관련성을 가지고 있었다. 이러한 결과는 훈련행동과 경기력을 예측할 수 있는 안정적인 성격변수로써 실패내성의 타당성과 후속 연구의 방향 등과 관련하여 논의하였다.

As Concrete is construction materials which is unevenly mixed with cement, aggregate and water, compressive strength and modulus of elasticity is an important factor to seize movement of structures. The purpose of this study is to investigate a correlation compressive strength and modulus of elasticity according to the size of structures, and also to analyze and compare to prediction equation of many countries.

통일형 품종들의 탈립성과 지경강도와의 관계를 구명하기 위해서 재래종 26, 통일형 30, Japonica 형 30 품종을 공시하여 낟알의 탈입률, 지경강도 및 섬유세포의 길이와 폭등을 조사하였던 바 그 결과는 다음과 같다. 1. 통일형 품종들의 낟알 탈락률은 평균 11.29%로 가장 높았으며, 다음이 재래종들로서 평균 2.56% 였고, Japonica 형 품종들이 가장 낮아서 평균 0.17%였으며, 또한 통일형 품종들은 낟알과 소지경사이에 형성되는 이층조직부위에서의 탈락도 많았으나, 지경의 절단에 의한 탈락도 많은 편이었다. 2. 통일형 품종들에 있어서 1차지경의 인장강도 및 항곡강도는 각각 평균 217g, 20.5g으로 재래종 Japonica 형 품종 보다 약하였다. 3. 통일형 품종들에 있어서 섬유세포의 길이는 평균 616um로 Japonica 형 품종이나 재래종보다 짧았으나, 섬유세포의 폭은 통일형이 7.6um 로서 재래종보다는 작고, Japonica 형 품종들보다는 큰 경향이었다. 4 낟알의 탈락율은 지종의 인장강도, 항곡강도 및 섬유세포의 길이와 유의적인 상관관계를 보였다.