• 소성∙가공
• /
• 제24권3호
• /
• pp.176-180
• /
• 2015

The current study is concerned with the prediction of fracture strains for DP980 steel sheets over a wide range of loading paths. The use of DP980 steel is increasing significantly in automotive industries for enhanced safety and higher fuel efficiency. The material behavior of advanced high-strength steels (AHSSs) sheets sometimes show unpredictable and sudden fracture during sheet metal forming. A modified Lou-Huh ductile fracture criterion is utilized to predict the formability of AHSSs because the conventional forming limit diagram (FLD) constructed based on necking is unable to evaluate the formability of AHSSs sheets. Fracture loci were extracted from three dimensional fracture envelopes by assuming the plane-stress condition to evaluate equivalent plastic strains at the onset of fracture for a wide range of loading paths. Three different types of specimens -- pure shear, dog-bone and plane strain grooved -- were utilized for tensile testing to calibrate the fracture model of DP980 steel sheets. Fracture strains of each loading path were evaluated such that there shows little deviation between fracture strains predicted from the fracture model and the experimental measurements. From the comparison, it is clearly shown that the three dimensional fracture envelopes can accurately predict the onset of the fracture of DP980 steel sheets for complicated loading conditions from compressive loading to shear loading and to equibiaxial tensile loading.

• 대한두개안면성형외과학회지
• /
• 제15권3호
• /
• pp.109-116
• /
• 2014

Background: Infants with deformational plagiocephaly (DP) usually present with cranial vault deformities as well as facial asymmetry. The purpose of this study was to use three-dimensional anthropometric data to evaluate the influence of cranial deformities on facial asymmetry. Methods: We analyzed three-dimensional computed tomography data for infants with DP (n=48) and without DP (n=30, control). Using 16 landmarks and 3 reference planes, 22 distance parameters and 2 angular parameters were compared. This cephalometric assessment focused on asymmetry of the orbits, nose, ears, maxilla, and mandible. We then assessed the correlation between 23 of the measurements and cranial vault asymmetry (CVA) for statistical significance using relative differences and correlation analysis. Results: With the exception of few orbital asymmetry variables, most measurements indicated that the facial asymmetry was greater in infants with DP. Mandibular and nasal asymmetry was correlated highly with severity of CVA. Shortening of the ipsilateral mandibular body was particularly significant. There was no significant deformity in the maxilla or ear. Conclusion: This study demonstrated that the cranial vault deformity in DP is associated with facial asymmetry. Compared with the control group, the infants with DP were found to have prominent asymmetry of the nose and mandible.

• 대한본초학회지
• /
• 제33권4호
• /
• pp.69-76
• /
• 2018

Objectives : Dracocephalum palmatum Stephan (Lamiaceae) is a medicinal plant used by the East-Russian nomads but there were few studies on this plant. This study was to evaluate anti-cancer effects of D. palmatum Stephan leaf hexane fraction on human derived prostate cancer cell death. Methods : The dried leaves of D. palmatum were dissolved in methanol, and hexane fraction (DpLH) was again obtained from lyophilized methanol extract (DpLM). DpLH was investigated by measuring by MTT assay and annexin V/PI staining to evaluate its effects on the cell viability and apoptosis of PC-3 cells. The ROS generations were detected by DCF-DA dye. The protein expressions were confirmed by p-AKT, Bcl-2, Bax, procaspase-3 activities. Results : After treatment of DpLH to PC-3 cells, the cell proliferation was significantly inhibited, and in addition, DpLH treatment also accelerated apoptosis of PC-3 cells. When DpLH was treated to the PC-3 cells, its ROS production significantly decreased. The proportion of all proteins (p-AKT/actin, Bcl-2/Bax and procaspase-3/actin ratios) showed decreasing tendency of expression compared with the control group. Conclusions : As shown in the above results, the extract from D. palmatum inhibits ROS production and promotes cell death, which is considered to be a relatively safe induction of cell death when administered to a living body. In conclusion, these results suggested that DpLH may have anti-cancer effect in human prostate cancer cell.

• 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.

• 식물병연구
• /
• 제17권3호
• /
• pp.358-363
• /
• 2011

경기도와 경상북도 일대의 '대석조생' 자두 재배포장에서 착색이 불균일한 얼룩 반점 증상의 과실이 발생하였다. 이들 시료로부터 유전자 진단(RT-PCR)과 Dot-blot hybridization 검정 결과 호프왜화바이로이드(HSVd)가 검출되었고 유전자 염기서열 분석을 통해 2개의 HSVd 변이주(DP1, DP2) 를 동정하였다. GenBank에 등록된 자두 HSVd의 7개 변이주와 새로운 DP1, DP2 변이주와의 유전자 염기서열을 비교분석한 결과 94-100%의 높은 상동성을 보였다. DP1와 DP2의 유전자는 59번과 60번 염기가 각각 CG, AA로 서로 다른 변이를 보였다. 국내외 자두 과실 얼룩반점 증상에서 동정된 HSVd의 유전자는 특이적으로 59번과 60번 부위의 염기가 CG, AA, TG인 3개 군으로 크게 구분되는 것을 알 수 있었다.

• Applied Biological Chemistry
• /
• 제35권3호
• /
• pp.196-201
• /
• 1992

분질 고구마인 수원 147과 점질인 황미로부터 전분을 분리하고 산가수분해 특성 및 X-ray 회절도를 통해 내부결합력 및 결정강도를 비교하였으며 겔크로마토그래피를 통해 산분해 잔사의 구조적 특성을 조사하였다. 수원 147이 황미보다 산가수분해에 강한 저항성을 보였으며 생전분의 결정화도와 산처리에 따른 전분들의 상대적 결정화도의 증가는 수원 147이 더 크게 나타났다. 산처리에 의하여 ${\beta}$-Amylolysis limit(%)는 점차 증가하였으며 겔크로마토그래피로 용출되는 분자크기가 크게 감소했다. 산분해 잔사는 중합도(DP) 25와 DP 15 부근의 2개의 peak로 분획되었다. Debranching 한 후의 분획은 DP 15부근의 단일 peak로 나타났고 peak의 DP에서 분질과 점질간 차이가 나타났다.

• 한국항해항만학회지
• /
• 제41권5호
• /
• pp.259-268
• /
• 2017

Formal Safety Assessment (FSA) has been mostly implemented on the hardware aspects of vessels. Although there are guidelines regarding human error FSAs, there have not been many assessments in such areas. To this end, this study seeks to use precedent studies for the safe operation of DP vessels, conducting an FSA regarding human error of DP LOP (Loss of Position) incidents. For this, the study referred to precedent studies for the frequency of DP LOP incidents caused by human errors, adding the severity of LOP incidents, and then applying them to the Bayesian network. As a result, the study was able to confirm that among DP LOP incidents caused by human errors, the drive-off from skill-based errors was 74.3% and the drive-off from unsafe supervision was 50.5%. Based on such results, RCOs (Risk Control Options) were devised through a brainstorming session with experts coming up with proposals including providing mandatory DPO training, installing DP simulator on the vessels, drawing up measures to understanding the procedures for safe operation of DP vessels. Moreover, it was found that mandatory DPO training is reasonable in terms of cost benefits and that while installing a DP simulator is not suitable in terms of cost benefits, it can significantly reduce risks when operating DP vessels.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2004년도 추계학술대회 논문집
• /
• pp.1128-1131
• /
• 2004

SFF(solid freeform fabrication) is another name of RP(rapid prototyping). The SFFS for office type wishes to develop system that can produce small object such as hand phone, cup, accessory etc. with high speed, and also intend suitable system in office environment by compact design, and buy easily by inexpensive price. As can manufacture high speed in existent SFF process technology, representative process that have competitive power in price is 3DP (three dimensional printing) technology. The 3DP technology is way to have general two dimensional printing technology and prints to three dimension, is technology that make three-dimensional solid freeform that want binder doing jetting selectively on powder through printer head. We designed and manufactured SFFS for office based on 3DP process technology design and manufactured, and composed head system so that use 3 printer heads at the same time to improve the fabrication speed of system. We used printer head of INCJET company and cartridge used HP45 series model who can buy easily in general city. And we directly fabricated three dimensional solid freeform using developed SFFS for office type.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2008년도 춘계학술대회 논문집 센서 박막재료연구회 및 광주 전남지부
• /
• pp.121-122
• /
• 2008

Blue emitting materials have been explored by various researchers. However, blue-emitting materials with high luminous efficiency, good color purity, and thermal stability are still much desired. In this study, we synthesized a new blue luminescent material, $SnDP(HPB)_2$ which is low molecular compound and thermal stability. The PL spectrum of $SnDP(HPB)_2$ was observed blue at the wavelength of 447nm. The ionization potential(IP) and the electron affinity(EA) of $SnDP(HPB)_2$ was measured to be 6.7 eV and 3.0 eV, respectively. The fundamental structure of the OLED was ITO/NPB/$SnDP(HPB)_2/Alq_3$/LiF/Al. As a Result, we obtained to enhance the performance of blue OLED.

• Ocean Systems Engineering
• /
• 제5권3호
• /
• pp.199-220
• /
• 2015

The paper described the nonlinear dynamic motion behavior of a barge equipped with the portable outboard Dynamic Positioning(DP) control system in short-crested waves. The DP system based on the fuzzy theory is applied to control the thrusters to optimally adjust the ship position and heading in waves. In addition to the short-crested waves, the current, wind and nonlinear drifting force are also included in the calculations. The time domain simulations for the six degrees of freedom motions of the barge with the DP system are solved by the $4^{th}$ order Runge-Kutta method. The results show that the position and heading deviations are limited within acceptable ranges based on the present control method. When the dynamic positioning missions are needed, the technique of the alternative portable DP system developed here can serve as a practical tool to assist those ships without equipping with the DP facility.