• 한국레이저가공학회지
• /
• 제2권1호
• /
• pp.61-67
• /
• 1999

This study introduces the new concept in the evaluation criteria of the $CO_2$ laser Tailored Blank weldability, The materials used are 0.7mm, 1.5mm thick low carbon automotive galvanized steels. Welding tests were conducted for both similar thickness(0.7mm-0.7mm, 1.5mm-1.5mm) and dissimilar thickness(0.7mm-1.5mm) cases. The criteria developed for optimum welding conditions were based on relationship between results of die press forming test, weld transverse tensile test Erichsen test and weld penetration measurements. Application of the developed criteria(fracture ratio, strength ratio and D/To) in obtaining optimum welding condition revealed that a weld which satisfied any of the criteria did not fracture during actual die press test.

• 대한치과기공학회지
• /
• 제33권1호
• /
• pp.1-6
• /
• 2011

Purpose: To examine the shear bond strengths of zirconia and veneering ceramic according to their surface processing. Methods: The test samples were divided into three groups: one without zirconia surface processing, one sandblasted, and one sandblasted then 3% etched. Then veneering ceramic was fired on all test samples, and their shear bond strengths were measured. Results: The test samples of the control group (Z1) showed the lowest shear bond strengths of $21.82{\pm}1.02$ MPa. The shear bond strengths of Z2 and Z3 ($28.25{\pm}0.72$ and $26.23{\pm}0.82$ MPa, respectively) were relatively higher than those of the control group. The fracture surface of the control group showed adhesive fractures while the test groups had relatively large numbers of cohesive fractures. Conclusion: The shear bond strength was high in the test groups with surface processing while the fracture surfaces showed compound fractures of adhesive and cohesive fractures.

• Journal of Welding and Joining
• /
• 제21권1호
• /
• pp.99-106
• /
• 2003

This research was aimed to evaluate the material degradation with various microstructures of X20CrMoV121 steel weldment by Advanced Small Punch(ASP) test. Due to the regional limitation on constitutive structures, the minimized loading ball(${\varphi}1.5mm$) and bore diameter of lower die(${\varphi}3mm$) were designed for the ASP test. The micro-hardness test was also performed to assess the mechanical properties with artificial aging heat treatment. Material degradation was estimated by ductile-brittle transition temperature(DBTT). The results obtained from the ASP test were compared with those from conventional small punch(CSP) test and CVN impact test for several weldment microstructures. It was found that the ASP test clearly showed the microstructural dependance on the material degradation in the weldment.

• 복합신소재구조학회 논문집
• /
• 제5권1호
• /
• pp.16-21
• /
• 2014

In the study, tensile, compression and in-plane tests about longitudinal direction of glass fiber were performed. Also, to obtain the material properties of GFRP fabric composite, tensile test was performed. All test were performed by the test method of ASTM. Maximum compressive strength was smaller than the maximum tensile strength at the longitudinal direction test results. Elastic modulus of the tensile and compressive was almost similar at the compression test results in the longitudinal direction. Based on the GFRP fabric composite test results, GF91 was showed good performance at maximum compressive, maximum strain and elastic modulus.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2007년도 추계학술대회 논문집
• /
• pp.301-305
• /
• 2007

The performance of the railway bogie is classified into the stability and the steering performance. Testing for the bogie stability is conducted on the roller rig. But testing for the bogie steering performance on test facility is very difficult, so the testing for the vehicle curving performance is conducted on the real curve track. And it is desirable to test on the full scale test rig, but it caused many problems relating to test costs, test time. To overcome these problems, the small scale test rig is actively used in the field of bogie stability. Thus, in this paper, we have studied the scale track to test the bogie steering performance. For this, we designed the 1/5 scale test track equivalent to radius 200 curve and confirmed the validity of the testing for the bogie steering performance on the scale curve track through the testing using 1/5 scale bogie.

• Communications for Statistical Applications and Methods
• /
• 제10권1호
• /
• pp.211-224
• /
• 2003

Good's lambda test, a permutation test used to detect the changes of microorganism composition under two pathological conditions, has been quite popular for studying the micro-flora responsible for periodontal disease. A vast number of different micro-flora in the mouth renders the traditional chi-square test inapplicable. The main purpose of this paper is to evaluate the power of this test so that the sample size can be determined at the design stage. The robustness of this test and its comparison to two other intuitive tests are also presented. It is found that a permutation test based on likelihood ratio is more powerful than the lambda test in our simulated cases.

• 한국응용약물학회:학술대회논문집
• /
• 한국응용약물학회 1993년도 제2회 신약개발 연구발표회 초록집
• /
• pp.171-171
• /
• 1993

발암물질의 조기검색법을 개발하고자 변이원성 물질의 스크리닝법으로 널리 사용되고 있는 Ames test 및 chromosomal aberration test를 본 연구에서 개발하고자 하는 DNA 및 Protein-adduct 형성시험법과 비교 연구하였다. 벤조피렌과 아플라톡신 B$_1$을 모델 발암물질로 하여 실시한 Ames test에서는 두 화합물 모두 양성을 나타냈으나 용량-반응 관계가 뚜렷하지 않았다. 또한 고농도에서는 시험물질의 독성체 의해 정상적인 Ames test의 수행이 어려됐다. Chromosomal aberration test에서도 Ames test와 비슷한 결과를 나타냈으며 특히 고농도에서 시험을 실시했을 경우 Ames test에서와 마찬가지로 세포독성의 현상이 관찰되었다. 그러나 본 연구에서 새로이 개발한 DNA 및 Protein-adduct형성 시험법은 저농도에서 고농도에 이르기까지 뚜렷한 용량-반응 관계를 나타냈으며 Ames test 및 chromosomal test에서 일어날 수 있는 false positive나 false negative의 결과를 가져다 줄 우려가 없다. 또한 시험시간이 1-2시간 정도 소요되므로 기존의 방법보다 시험시간을 약 40배 가량 단축시킬 수 있었다.

• 대한조선학회논문집
• /
• 제35권1호
• /
• pp.54-60
• /
• 1998

일반적으로 선박의 보침성능을 평가하기 위해서 spiral test가 이용되고 있다. 그러나 spiral curve를 얻기 위한 spiral시험 및 역spiral시험에 있어서 바람과 파도 등의 영향으로 많은 어려움이 따른다. 따라서 spiral 시험을 하지 않고도, zig-zag test의 overshoot angle을 이용하여 선박의 보침성능을 판정하는 방법이 시도되고 있다. 본 연구에서는 실선의 spiral 시험결과를 대상으로, K-T 조종수학모델을 적용하여 zig-zag 운동을 계산하고, overshoot angle과 보침성능과의 상관관계를 조사하였다.

• 소성∙가공
• /
• 제31권1호
• /
• pp.23-28
• /
• 2022

Although the hole expansion test is currently the most commonly used method to evaluate the stretch flangeability of HSS, it has been criticized due to its poor repeatability and reproducibility for test results. This paper focuses on the development of a new measurement method to investigate the stretch flangeability of HSS. Two materials (DP590, DP980) were investigated with a hole expansion test and a developed test method. Test results showed that the developed test method could be used as one stretch flangeability test to help identify relevant parameters of the shearing process to avoid edge cracking.

• Elastomers and Composites
• /
• 제8권2호
• /
• pp.140-147
• /
• 1973

The influence of the adhesive force test conditions on the resultant adhesive force was measured using a chloroprene rubber as an adhesive and a plywood as an adherent. It was clarified from the experiments which adhesive force test conditions could influence strongly the adhesive force. After this, the constant values neccessary as the test conditions of the adhesive force in making generally a test of the adhesive force determined.