• 한국공간구조학회논문집
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• 제6권3호
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• pp.69-76
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• 2006

콘크리트 충전 강관(Concrete Filled Steel Tube : CFT) 기둥은 내력 및 변형능력 등 구조적 성능이 뛰어남에도 불구하고 강관내부에 충전한 콘크리트의 재료분리저항성 및 유동성이 확보되는 고품질의 콘크리트가 요구되며, 또한, 다이어프램 하부의 충전 확인이 어렵다는 문제점을 안고 있다. 따라서 CFT기둥의 장점인 내력 및 시공성을 살리고, 현장 충전 공법에서의 단점을 극복하기 위하여 CFT부재의 PC화가 연구되어 왔다. 그러나 CFT부재의 PC화는 고중량물이기 때문에 운반과 양중능력의 확보 등 다른 문제를 낳게된다. 본 연구에서는 현장타설 CFT기둥의 단점과 공장생산 CFT기둥의 단점을 보완하기 위하여 새로운 형태인 중공 CFT 구조를 제안하고 중심축하중 하의 이력특성에 대한 기본적인 연구를 수행하였다. 이를 위하여 설정된 주된 실험변수는 CFT기둥의 충전율과 충전재의 강도이며, 특히 충전율은 0%, 30%, 50%, 80%, 100%를 설정하였다. 얻어진 결과는 기본적으로 항복강도레벨에 이르기까지 선형적인 거동을 나타내고 있으며, 내부 충전율이 증가함에 따라 강도, 강성 및 변형능력이 크게 나타나고 있다.

• 구강회복응용과학지
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• 제19권3호
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• pp.139-151
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• 2003

This study was to evaluate and to compare the compressive strength and the displacement effecting the abutment or the residual ridge which are transformed by the angle and the heights of the konus denture inner crown when restorating the unilateral konus denture by using the mandibular canine and the 1st premolar as an abutment. The author made 9 different models for different inner crown heights and konus angles. The inner crown height were divided to 5mm, 6mm, and 7mm and konus angles was divided to $4^{\circ}$, $6^{\circ}$, and $8^{\circ}$. And then in each model, 5kg of $15^{\circ}$ mesial load was stressed on the central fossa of the 1st premolar and the 1st molar. The stresses and displacement were measured using the finite element analysis. The results were as follows 1. The maximum compressive strength was shown on the connective area of the abutment and the denture base. 2. As the angle of the inner crown becomes increased, the compressive strength was shown smaller. 3. As the height of the inner crown becomes increased, the maximum compressive strength was shown smaller while the compressive strength of the root apex and the residual ridge showed larger. 4. When the stress was loaded only on the 1st premolar, the more compressive strength was concentrated on the root apex area of the 1st premolar. 5. When the stress was loaded only on the 1st premolar, the compressive strength was concentrated uniformly on the abutment and the residual ridge. 6. When the stress was loaded only on the 1st molar, the maximum displacement was shown on the distal part of the residual ridge.

• 한국지반공학회논문집
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• 제17권6호
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• pp.235-244
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• 2001

액상화는 비배수조건에서 흙 강도의 갑작스러운 감소에 기인한다. 이러한 흙 강도의 손실은 과잉간극수압의 발현과 관련된다. 본 연구에서는 최대 및 최소간극비에 영향을 미치는 세립분 함유량이 조사되었다. 또한 포화된 실트질 모래에 대한 정적 및 동적 삼축시험의 결과를 제시하였다. 이들 시험은 액상화강도와 정적 및 동적 거동 특성을 평가하기 위해 수행되었다. 시료는 새만금 유역에서 채취되었으며 공기건조되었다. 결과를 요약하면 다음과 같다. 1) 최대 및 최소간극비선은 유사한 경향으로 나타났다. 2) 최대 및 최소간극비는 20~30%의 세립분 함유량에서 얻어졌다. 3) 구속압력과 과압밀비가 증가할수록 액상화에 대한 저항은 증가하였다. 4) 불안정마찰각은 초기상대밀도의 증가와 함께 커졌다. 5) 유효응력비가 증가함에 따라 액상화에 대한 저항은 감소하였다.

• 한국군사과학기술학회지
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• 제16권3호
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• pp.358-364
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• 2013

Borosilicate glass(GVB-Solutions in glass, 2mm, Germany) was prepared in the composition of $80.4SiO_2-4.2Na_2O-2.4Al_2O_3-13.0B_2O_3$. The 2-step crystallization was performed around $584^{\circ}C$ of glass transition temperature ($T_g$), and $774^{\circ}C$ of crystallization temperature($T_c$). The maximum nucleation rate was $8.8{\time}10^9/mm^3{\cdot}hr$ at $600^{\circ}C$ and the maximum crystal growth rate was 3.5nm/min at $750^{\circ}C$. The maximum mechanical properties were observed at 22.8% of volume fraction, the strength, hardness and fracture toughness was 555MPa, $752kg/mm^2$, $1.082MPa{\cdot}mm^{1/2}$. The crystal size of 177nm which has volume fraction of 22.8% showed maximum strength of 562MPa, it is about 157% higher than parent borosilicate glass. From these results, the crystallized borosilicate glass can be applied weight lighting of bullet proof materials.

• Elastomers and Composites
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• 제38권4호
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• pp.354-362
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• 2003

The use of a petaloid design for the bottom of carbonated poly(ethylene terephthalate)(PET) bottles is widely spread. This study investigated the causes of bottom cracks. The tensile yield stress variations of PET according to the crystallinity and stretch ratio were examined, then the stretch ratio and strength in the bottom area of a blown bottle were analyzed. A crack test was also performed to observe the cracking phenomena. The distribution of the effective stress and maximum principal stress were both examined using computer simulation to seek the influence of the bottom design on crack. It was concluded that the bottom cracks occurred because of inadequate material strength due to the insufficient stretching of PET, plus the coarse design of a petaloid bottom. The stretch ratio at the bottom during bottle blowing should be higher than the strain hardening point of PET to produce enhanced mechanical strength. The cracks in the bottom of the PET bottles occurred through crazing below the yield stress. The maximum principal stress was higher in the valleys of the petaloid bottom than in the rest bottom area, and the maximum principal stress had a strong effect on the cracks.

• 한국안전학회지
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• 제26권4호
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• pp.1-6
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• 2011

New methods for joining sheet of metal are being sought. One of the most promising methods is MPJ (mechanical press joining). It has been used in thin metal work because of its simple process and relative advantages over other methods, as it requires no fasteners such as bolts or rivets, consumes less energy than welding, and produces less ecological problems than adhesive methods. In this study, the joining process and static behavior of single overlap joints has been investigated. During fixed die type joining process for SPCC plates, the optimal applied punching force was found. The maximum tensile-shear strength of the specimen produced at the optimal punching force was 1.75 kN. The FEM analysis result on the tensile-shear specimen showed the maximum von-Mises stress of 373 MPa under the applied load of 1.7 kN, which is very close to the maximum tensile strength of the SPCC sheet(= 382 MPa). This suggests that the FEM analysis is capable of predicting the maximum tensile load of the joint.

• 산업경영시스템학회지
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• 제23권56호
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• pp.45-53
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• 2000

A laboratory experiment was conducted to investigate the effects of body posture and of different types of common non-powered hand tools on maximum volitional torque exertion capabilities of Korean. Fifteen males and 15 females were participated in the experiment. Each subject exerted maximum volitional torque in 15 different body postures while using five different common non-powered hand tools. Results of the data analysis showed that, for both males and females, the magnitude of torque exertion is significantly affected by the type of tool and posture. Also the result indicated that females exerted only about 51.5% of torque when compared to that of males. This result is different with the general findings in the field of ergonomics that the muscular strength of female is usually 65% to 75% of male. It suggests that application of same profile of muscular strength of female as in the western population should be carefully considered in oriental countries since females in this region may possess less physical capability compare to that of western females in terms of percentage muscular strength of males. Profiles of maximum torque capabilities of Koreans are provided.

• 한국염색가공학회지
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• 제34권2호
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• pp.127-133
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• 2022

With the increasing interest in the expression of individuality and appearance of modern people, it is time to conduct research and development of novel hair coloring from various angles. Therefore, taking into account the order of discoloration of hair pigments, we selected a creative and novel emulsion as a novel material for hair coloring, rather than a cosmetic material such as hot water extract using natural products dealt with in previous studies, commercially available hair manicure, and oxidation hair dye for hair. Thus, the change in tensile strength and elongation of hair samples by color was studied. As a result of the study, hair with green emulsion paint had a significantly higher maximum load, maximum stress, maximum elongation and breaking load, breaking stress, breaking elongation values are shown. Maximum in terms of modulus, green emulsion applied hair and the control group were higher in the 0-15s strain and 15-145s sections, respectively, and the tangential modulus value was much higher in the control group than the experimental group hairs in all the 0-145s sections. This study, which analyzes the dynamic changes of hair samples that extend the daily color gamut, will greatly contribute to the development of innovative hair coloring materials in the research and production of hair beauty works, and it is judged that it will also contribute to the development of the beauty industry.

• 대한정형도수물리치료학회지
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• 제17권1호
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• pp.9-14
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• 2011

Background: The purpose of our experimental study, we want to know a correlation study using the sonogram between the muscle strength and the diameter of Biceps brachii muscle by gender. So we set to hypothesis that Biceps brachii contracted maximally would be a diameter of the muscles increased according to the muscle strength will be increased. Methods: In this study, we measured the muscle strength of biceps brachii on contracting its maximum using the Biodex and the diameter of the muscles using Myo-Lab (25Gold). We experimented 30 subjects of twenty-aged men and women. The subjects is comprised of a persons who has not external injuries and pain of elbow joint, no mobility limitation of ROM, no experiences of surgery in past history. Result: We found that the men have a highly correlation between maximum strength and the diameter of the muscles more than women (p<.05). Conclusion: The results of our experimental study between the muscle diameter and the muscle strength to biceps brachii on relaxation and contraction is a statistically significant relation (r=.394), especially in rather men then women (p<.05). So this results would be based data for further clinical muscle efficiency application in physical therapy field.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 춘계학술대회 논문집 센서 박막재료연구회 및 광주 전남지부
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• pp.50-53
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• 2008

In this work, the $TiO_2$ pigment influence in HDPE dielectric strength was analyzed. Chemical and structural characterizations were made to identify changes during the processing and your influence in the electrical properties. Formulations containing 0, 0.5, 1, 2.5, 4 and 6 of titanium dioxide were processed by extrusion and injection molding with stabilization-antioxidants, ultraviolet stabilizers and plasticizers. The electrical strength tests were analyzed by the statistical distribution of Weibull, and the maximum likelihood method. The high concentrations present lower values to electrical strength. The $\beta$ parameter could be using to insulator particles dispersion. The $TiO_2$ concentration variation shows that these incorporations implicate strength values increase has a maximum (5,35MV/cm). High pigment concentration induces a little falls in property values. Observing the $\beta$ parameter, minimum experiment electric field (Ebmin) and electric strength value, found that the best electric perform formulation was the formulation with 2.5% $TiO_2$ weight.