• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2004년도 춘계학술대회 논문집
• /
• pp.365-372
• /
• 2004

1)고강도강 BOP 시험 결과 강종에 차이 없이 용접속도에 따라 유사한 비드 형상을 가지는 것으로 나타났다. 한편 1.2t 시험편의 적정 용접속도는 $4\~8m/min$으로 나타났다. 2) 용접속도가 빠를수록 비드폭은 작아지며, 경도값은 높게 나타났다. 그리고, 최고 경도값은 강의 성분(Ceq)에 비례하는 것으로 나타났음, 그 결과 TRIP80(Ceq=0.53)의 경우 최고 520Hv이상의 경도값을 가지고 있었다. 3) LDH test 결과 DP강의 모재대비 용접부의 성형성이 약 $90\%$ 정도로 나타났으며, TRIP 및 일반 고강도강은 약 $80\%$의 성형성을 갖는 것으로 확인되었다. 4) He을 보호가스로 사용시 기공의 형성은 크게 억제되었다. 그리고 Ar 사용시에는 기공 형성이 He에 비해 많이 형성되는 것으로 나타나 사용시 주의가 필요한 것으로 보인다. 기공 형성은 TRIP > 60C/45R > DP 순서로 나타나 DP강이 가장 좋은 레이저 용접성을 가지고 있었다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제3권3호
• /
• pp.231-242
• /
• 1990

A study is reported which investigated the additive nature of digestible energy (DE) from dietary nutrients and to estimate the relative energy values of different energy-yielding nutrients in practical trout diets. A growth study was conducted over 12 weeks with 6 diets. Rainbow trout (Oncorhynchus mykiss) were fed diets once a day ad libitum. Digestible energy values determined and calculated had direct relationship indicating additive nature of such values for feed ingredients. Overall growth performance was best in a diet containing 33% digestible protein (DP) with a DP/DE ratio of 18.6. A reduction in digestible protein level with the same DP/DE rat io led to a significant decrease in growth and feed efficiency. The increase of 7% of lipid with concomitant decrease in protein resulted in the relative gain of 130% in growth and nutrient retention, suggesting that 1 g of lipid is equal to about 1.3 g of proteins in terms of net energetic value. Replacement of 10% of dietary lipid by carbohydrates led to a slight decrease in energy retention efficiency but to a great increase in lipid retention efficiency (130%) showing that dietary carbohydrates led to increased lipogenesis.

• 한국가금학회지
• /
• 제40권4호
• /
• pp.315-325
• /
• 2013

본 논문은 분말된장의 첨가가 닭고기 소시지의 품질 및 저장성에 미치는 영향을 구명하기 위하여 분말된장을 첨가하지 않은 대조구(C)와 분말된장 2% 첨가구(DP2), 분말된장 5% 첨가구(DP5), 분말된장 8% 첨가구(DP8)로 나누어 일주일 간격으로 총 4주간 실험을 실시하였다. 실험 결과, pH에서는 분말된장 처리구가 분말된장을 첨가하지 않은 대조구(C)에 비해 유의적으로 낮은 값을 보였다(p<0.05). TBARS에서는 분말된장 첨가구가 대조구(C)에 비해 지방산패를 억제함을 알 수 있었으며(p<0.05), 분말된장 5% 처리구(DP5)가 저장 4주차에 다른 처리구들에 비해 유의적으로 낮은 TBARS 값을 나타내었다(p<0.05). 단백질 변패를 나타내는 VBN은 분말된장 8% 처리구(DP8)가 다른 처리구들에 비해 유의적으로 높은 값이 나왔다(p<0.05). 닭고기 소시지의 보수력은 된장분말 첨가에 의한 영향을 받지 않았다(p<0.05). 표면육색 측정 결과, 명도 값은 분말된장 첨가구가 대조구에 비해 유의적으로 낮았으며(p<0.05), 적색도 및 황색도에서는 분말된장 5% 처리구(DP5)가 다른 처리구들에 비해 유의적으로 높은 값을 보였다(p<0.05). 조직감 측정 결과, 경도, 탄력성, 점성, 씹힘성 항목에서 분말된장 5% 처리구(DP5)와 분말된장 8% 처리구(DP8)가 다른 처리구들에 비해 유의적으로 낮은 값을 보였다(p<0.05). 닭고기 소시지의 저장 중 총 호기성 및 혐기성균은 분말된장 5 및 8% 첨가에 의해 증식이 억제되는 것이 확인되었다. 이상의 결과를 종합해 볼 때 닭고기 소시지 제조 시 분말된장의 첨가는 무첨가구에 비해 저장성이 우수한 소시지를 만들 수 있을 것으로 예상되며, 한국 전통양념을 이용한 육가공 식품이 전무한 시점에서 이화학적으로 새로운 맛의 제품을 만들어 소비자들의 이목을 끌 수 있을 것으로 사료된다.

• 대한산업공학회지
• /
• 제26권4호
• /
• pp.315-324
• /
• 2000

This paper presents an efficient dynamic programming(DP) method, so called EDPAS (Efficient Dynamic Programming Algorithm for Signal), for optimally controlling traffic signal in real-time mode at a single intersection. The objective of EDPAS is to minimize total vehicle delay. It applies reaching method to solve forward DP functional equation, which does not need any priori knowledge on the states of DP network. Two acceleration techniques within reaching method are the main feature of EDPAS. They are devised to eliminate inferior DP states by comparing between states and maintaining incumbent value, resulting in a great amount of computational efficiency. An example is shown to verify the advantage of EDPAS.

• Journal of Electrical Engineering and Technology
• /
• 제10권3호
• /
• pp.1114-1123
• /
• 2015

Bushing is the key link to connect outer and inner insulating systems and also the essential electric accessory in electric power system, especially in the high voltage engineering (AC 1000kV, DC 800kV). This paper presented the experimental research of thermal aging characteristic of oil-paper insulation used in bushing. A thermally accelerated aging experiment at 90℃ was performed. The bushing models containing five layers of paper were sealed into the aging vessels and further aged for 250 days. Then several important parameters associated with the aging were observed and evaluated. The results showed that the degree of polymerization (DP) of papers gradually decreased. The DP values of outermost layer and middle layer fit well into the second-order kinematic model and first-order kinematic model, respectively. Less deterioration speed of the inter-layer paper than outer layer was confirmed by the variation of DP. Hydrolysis was considered as the main cause to this phenomenon. In addition, the logarithm of the furfural concentrations in insulation oil was found to have good linear relationship with DP of papers. Interestingly, when the aging time is about 250 days and DP is 419, the aging process reaches an inflection point at which the DP approaches the leveling off degree of polymerization (LODP) value. Both tanδ and acid number of oils increased, while surface and volume resistivity of papers decreased. The obtained results demonstrated that thermal aging and moisture absorbed in papers brought great influence to the degradation of insulating paper, leading to rapid decrease of DP and increase of the tanδ. Thus, the bushing should be avoided from damp and real-time monitoring to the variation of tanδ and DP values of paper is an effective way to evaluate the insulation status of bushing.

• 한국임상수의학회지
• /
• 제18권4호
• /
• pp.402-410
• /
• 2001

This study was performed to investigate the hemodynamic changes which occur after occlusion of coronary artery and relation to reperfusion arrhythmias(RA) which occur when occlusion materials were removed form coronary artery in dogs. The occlusion of coronary artery was designed by temporary ligation of left circumflex branch of coronary artery during 30 minutes in 16 dogs. During occlusion of coronary artery, cardiac output(CO), mean aortic pressure (mAP), aortic systolic pressure(ASP), aortic diastolic pressure(ADP). left ventricular systolic pressure(LVSP), left ventricular maximum dp/dt (LV max. dp/dt) and left ventricular end-diastolic pressure (LVEDP) were measured. The occurrence of RA were observed for 5 minute after reperfusion by explained of ligation. As a results, cardiac arrest occurred in 4 dogs during occlusion of coronary artery, and RA was not observed in 5 dogs while it was seen in 5 dogs when explained ligation(reperfusion) after 30 minutes, the rest 2 dogs occurred temporary tachycardia. In hemodynamics changes, LVSP decreased by 10.9% and LV max. dp/dt by 5.4 % in comparison to control value which not ligated coronary artery, and LVEDP increased by 73.3%. The CO/min and mAP also decreased by 10.7% and by 11.3% expectedly. In the relationship to occurrence RA and hemodynamics changes, the LVSP and LV max. dp/dt at the time of occlusion in the RA group decreased by 11.9% and 0.8% in comarison to the control value while the decrease was 7.7% and 10% in the non-RA group. But the LVEDP in creased by 109.1% in the RA group while the decreased was 44.6% in the non-RA group. Referring CO/min, the drop was 8.8% in the RA occurrence group and 12.9% in the non-occurence group. These parameters of LVEDP, LV max. dp/dt, and CO were significant difference(p<0.05). The mAP also decreased by 11.9 in the RA group and by 9.8% in the non-RA group, but these defference were not the significant difference.

• 한국재료학회지
• /
• 제21권11호
• /
• pp.581-586
• /
• 2011

This study describes a hydrogen embrittlement evaluation of the subsurface zone in 590DP steel by micro-Vickers hardness measurement. The 590DP steel was designed to use in high-strength thin steel sheets as automotive materials. The test specimens were fabricated to 5 series varying the chemical composition through the process of casting and rolling. Electrochemical hydrogen charging was conducted on each specimen with varying current densities and charging times. The relationship between the embrittlement and hydrogen charging conditions was established by investigating the metallography. The micro-Vickers hardness was measured to evaluate the hydrogen embrittlement of the subsurface zone in addition to the microscopic investigation. The micro-Vickers hardness increased with the charging time at the surface. However, the changing ratio and maximum variation of hardness with depth were nearly the same value for each test specimen under the current density of 150 mA/$cm^2$ and charging time of 50 hours. Consequently, it appears that hydrogen embrittlement in 590DP steel can be evaluated by micro-Vickers hardness measurement.

• 대한치과기공학회지
• /
• 제44권4호
• /
• pp.126-131
• /
• 2022

Purpose: The purpose of this study is to evaluate the quality of dental fixed prostheses fabricated by 3DP (three-dimensional printing). Methods: Ten main models were prepared for the study. Ten specimens were printed by 3DP (3DP group). Ten specimens were fabricated by the lost wax technique and casting method to complete the control group (LWC group). The marginal fit was measured for 20 specimens. The measurement of marginal fit was performed using the silicon replica technique. Finally, the marginal fit of 10 specimens from each group was calculated. An independent sample t-test was run to see if the calculated averages for the two groups were mutually significant (α=0.05). Results: According to the experimental results, the mean marginal fit of the 3DP group was 71.9 ㎛, and the LWC group was 55.3 ㎛. The means of the two groups were found to be significantly different (p<0.001) in the results of the independent sample t-test. Conclusion: The marginal fit of fixed dental prostheses produced by 3DP technology was examined with values greater than those fabricated by traditional technology. However, as it appeared to be a value within the range of clinically acceptable range recommended by numerous studies, it was determined that clinical application would be feasible.

• ETRI Journal
• /
• 제42권4호
• /
• pp.619-632
• /
• 2020

Highly dispersive S-boxes are desirable in cryptosystems as nonlinear confusion sublayers for resisting modern attacks. For a near optimal cryptosystem resistant to modern cryptanalysis, a highly nonlinear and low differential probability (DP) value is required. We propose a method based on a piecewise linear chaotic map (PWLCM) with optimization conditions. Thus, the linear propagation of information in a cryptosystem appearing as a high DP during differential cryptanalysis of an S-box is minimized. While mapping from the chaotic trajectory to integer domain, a randomness test is performed that justifies the nonlinear behavior of the highly dispersive and nonlinear chaotic S-box. The proposed scheme is vetted using well-established cryptographic performance criteria. The proposed S-box meets the cryptographic performance criteria and further minimizes the differential propagation justified by the low DP value. The suitability of the proposed S-box is also tested using an image encryption algorithm. Results show that the proposed S-box as a confusion component entails a high level of security and improves resistance against all known attacks.

• 분석과학
• /
• 제17권4호
• /
• pp.315-321
• /
• 2004

The aim of this study was to investigate the evidential value of blue and black ballpoint pens on paper by nondestructive techniques. In this work, 21 blue and 22 black ballpoint pens which were purchased on different brands were analyzed by Raman Spectroscopy and Video Spectral Comparator (VSC). Surface-Enhanced Resonance Raman Spectroscopy (SERRS) with excitation at 685 nm and VSC with several spot light filters were used for the discrimination of ballpoint pen inks. In the SERR spectra, the ballpoint pen inks on paper could be shown sharp spectral bands and distinguished by their band shapes and relative intensities. In the blue and black ballpoint pen inks, the discriminating powers (DP) by SERRS were 0.85 and 0.67 and the DP by VSC were 0.88 and 0.90, respectively. The DP by combined sequence of techniques was all 0.97 in both black and blue ballpoint pen inks.