• 한국잠사곤충학회지
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• 제14권1호
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• pp.43-47
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• 1972

견층부위별견사의 기계적특성을 파악하고저 Deniroscope와on을 이용하여 실험한바 다음과 같은 결과를 얻었다. 1) 견층별견사의 건조 및 습윤절단강도는 견사섬도감소율에 비례하여 저하한다. 2) 내층견사의 습윤항장력은 외층견사에 대하여 37%로 나타났다. 3) 습윤처리에 의한 전견층의 절단강도(g/d) 31%, 감소하였다. 4) 대섬도당 견사의 건조 및 습윤절단강도는 내층견사가 제일 높았다. 5) Apparent young's modulus는 내층견사에서 증가하였다. 6) 습윤견사의 절단신도는 건조견사에 비해 15% 증가하였다.

• 소성∙가공
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• 제8권3호
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• pp.283-283
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• 1999

In the present study, the effect of microporosity on the tensile properties of as-cast AZ91D magnesium alloy was investigated through experimental observation and numerical prediction. The test specimens were fabricated by die-casting and gravity-casting. For gravity-casting, the inoculation and use of various metallic moulds were applied to obtain a wide range of microporosity. The deficiency of the interdendritic feeding of the liquid phase acted as d dominant mechanism on the formation of the micropores in the Mg-Al-alloys, rather than the evolution of hydrogen gas. Although tensile strength and elongation has a nonlinear and very intensive dependence upon microporosity, the yield strength appeared to have a linear relationship with microporosity. However, it was possible to quantitatively estimate the linear contribution of microporosity on the individual tensile property far a range of microporosity, which was below about B %. The numerical prediction suggests that the effect of microporosity on fractured strength and elongation decreased as the strain hardening exponent increased. Furthermore. the shape and distribution of micropores may play a more dominant role than local plastic deformation on the tensile behavior of AZ9lD alloy.

• 대한치과기공학회지
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• 제25권1호
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• pp.81-87
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• 2003

Ti-20%Zr-X%Cr(X=0,5) based alloys not containing hamful Al and V were newly designed in order to reveal their possibility for dental casting alloys, and melted in argon-arc casting machine. The mechanical properties were evaluated by using universal testing machine. The tensile strength and %elongaton of the alloys markedly increased with Cr content. The Ti-20%Zr-5%Cr alloy showed a similar tendency with Ti-6%Al-4%V alloy in tensile strength, but surpassed in %elongation. From these results, it was concluded that new alloys for successful dental casting materials should be designed as Ti-Zr-Cr based alloys.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 춘계학술대회논문집
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• pp.163-170
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• 1999

Although the bulge forming technique is currently employed in commercial superplastic forming processes, the uniaxial tensile test is still the most commonly used method for the evaluation of the superplasticity of materials due to its simplicity in testing. However, the results obtained from the uniaxial tensile test can not be applied in analyzing the characteristics of the real parts formed in multi-axial stress state. In this paper, using the tensile test specimen obtained from the square cup manufactured by superplastic forming, tensile strength and elongation have been investigated according to the strain and cavity volume fraction. From the result of experiment, tensile strength and elongation are decreased according to the strain and cavity in Al-6%Cu-0.4%Zr alloy. On condition of uniaxial stress, cavity volume fraction is increased on linear according to the increasement of thickness strain. However, on condition of biaxial stress there are critical point( E t=1.5-1.6) that the slope, the ratio of cavity volume fraction and strain, have been changed. Therefore, cavity volume fraction is different with respect to stress condition, although the same strain.

• 한국산업융합학회 논문집
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• 제24권3호
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• pp.261-269
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• 2021

This study was evaluated the elastic wave properties according to tension of Incoloy 825 alloy with different solution treatment temperature and aging time. Solution treatment was carried out at 700, 800, 900, and 1000 ℃ for 1 hour, and aging was carried out at 700 ℃ for 1, 5, 10, and 30 hours. As the solution treatment temperature increased, the tensile strength decreased and the elongation increased. However, as the aging time increased, the tensile strength increased and the elongation decreased. The dominant frequency decreased as the solution treatment temperature increased, but increased as the aging time increased. The dominant frequency according to the solution treatment and aging time increased as the tensile strength increased, but increased despite the decrease in elongation.

• 한국해양공학회지
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• 제27권4호
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• pp.9-13
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• 2013

The tensile properties of high manganese austenitic stainless steel with the two phase structures of deformation-induced martensite and reversed austenite were studied. Reversed austenite with an ultra-fine grain size of less than $0.3{\mu}m$ was obtained by reversion treatment. The two phases structures of deformation-induced martensite and reversed austenite were obtained by an annealing treatment in the range of $500^{\circ}C-700^{\circ}C$ for various times in 70% cold- rolled high-manganese austenitic stainless steel. The volume fraction of the reversed austenite increased rapidly with increases in the annealing temperature and time. In the stainless steel with the two phases of austenite and martensite, the strength decreased rapidly, while the elongation increased slowly and then rapidly increased with an increase in the volume fraction of the reversed austenite. Therefore, the strength and elongation were strongly controlled by the volume fraction of reversed austenite. A good combination of high strength and elongation could be obtained by the mixed structure of reversed austenite and deformation-induced martensite.

• 한국의류산업학회지
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• 제10권2호
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• pp.236-241
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• 2008

Hair manicure is usually and widely operated in the area of hair-dyeing by the reason that acidic hair color is less damaged and more stable than other chemical color treatment. However, there is no an in-depth study to prove them. This study purposes to provide basic resources for effectively using products of hair manicure by experiments on Physical Properties of Hair. Hair of one healthy woman in mid-20's, Level 4, was sampled for experiments. For the tests, hair samples were classified by the frequency of hair manicure treatment The control group(a), once treatment(b), twice(c), three times(d), four times(e) and five times(f). The results were measured with Scanning Electron Microscopy(SEM) and Tensile Strength and Elongation test. The lower Values of Tensile Strength according to repeated hair manicure treatment. Elongation is not affected by the frequency of hair manicure treatment. There was no remarkable change of hair surface in once(b) and twice(c) treatment. The change of hair surface which was able to judge by cuticle layers looseness, tunics and the transformation of cuticle cell were observed in the hair samples operating more than three times(d) of hair manicure treatment.

• Carbon letters
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• 제8권2호
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• pp.115-119
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• 2007

Properties of carbon blacks and carbon black/SBR rubber composites filled by surface modified carbon blacks were examined. Although the specific surface area of carbon blacks increased after the surface modifications with heat, acid, and base, there were no obvious changes in resistivity. The composites filled by heat treated carbon blacks showed a higher tensile strength and elongation than those filled by raw blacks. The acid and base treated carbon blacks filled composites also showed higher tensile strength but similar elongation values with those filled by raw blacks. With increasing loading ratio, both tensile strength and elongation increased, and appeared a maximum value at 30-40 phr. Modulus at 300% strain remained increasing with further loading of carbon blacks. At the same loading, the heat treated black filled composites showed similar modulus values with composites filled by raw blacks but for base and acid treated black filled composites much higher values were obtained. After the surface modification, the functional groups which played an important role in reinforcement action were changed.

• 한국주조공학회지
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• 제17권5호
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• pp.443-449
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• 1997

The purpose of this study is to investigate the effect of P addition and homogenizing heat treatment on the mechanical properties of Cu-Sn-Ni alloy. The addition of P was 0.025wt.%P to 0.085wt.%P and homogenizing heat-treated at 400, 500, $600^{\circ}C$ under $N_2$ gas atmosphere. Mechanical properties was investigated in this study were Rockwell hardness, tensile strength, and elongation. Tensile strength and elongation increased with P and homogenizing time. Temperature was significantly influence on mechanical properties. Hardness decreased with increasing homogenizing time and temperature, but 0.085wt.%P specimen was showed higher hardness and lower tensile strength and elongation than 0.073wt.%P specimen due to the presence of more $Cu_3P$ in matrix.

• 한국안전학회지
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• 제20권3호
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• pp.58-63
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• 2005

In this research, silicone rubber with additions of inorganic filler, alumina trihydrate$(Al(OH)_3\;:\;ATH)$, was aged acceleratedly and cyclically by the salt-fog and heating. The optimum amount of ATH addition to silicone rubber have been investigated by measurements of leakage current in the change of electrical properties and tensile strength, %elongation in mechanical properties and FT-IR, TG, SEM in the change of the chemical properties. With regard to un-aged silicone rubber, as the ATH addition amount increases, conductive path formation time was shortened in the electrical properties and tensile strength was increased, %elongation was decreased. In case of identical ATH addition amount, as cyclic aging increases, surface resistivity, tensile strength and %elongation were decreased. Considering the cyclic aging, the most effective amount of ATH addition was about 90phr.