• Title/Summary/Keyword: 열림

Search Result 280, Processing Time 0.031 seconds

A Study on Fatigue Crack Growth Characterization Of Surface Crack In Pressure Vessel Materials (압력용기 소재에서의 표면균열의 피로균열 성장특성에 관한 연구)

  • 허용학;이주진;한지원;김종집;문한규
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.14 no.1
    • /
    • pp.96-102
    • /
    • 1990
  • Cracks found in pressure vessels have been reported to be mostly semi-elliptic surface cracks. The fatigue crack growth behaviour of the surface cracks on pressure vessel materials, SPV 50Q and API 5A-K55, was studied with the consideration of the crack opening character. To determine the crack opening loads for the surface cracks, the displacement/strain were measured at three positions; the center and the side of the surface crack, the back face of the specimen using CMOD gauge and strain gauges. The experimental results showed that the crack opening load levels measured at the side of the surface crack were generally a little higher than those measured at the back face. As for the crack growth rates at the different parts of the surface crack, the experiments also showed that, if .DELTA.K$_{eff}$ is used, the exponent n of the Paris' law obtained were the same for the rear and the side parts of the surface cracks.

Hypospadias and Megacolon in a Persian Cat (페르시안 고양이에서 발생한 요도밑 열림증과 거대결증증)

  • Kim, Sung-Eon;Choi, Ran;Park, Jasil;Yang, Hye-Mi;Hyun, Changbaig
    • Journal of Veterinary Clinics
    • /
    • v.31 no.5
    • /
    • pp.454-456
    • /
    • 2014
  • A 9-month-old intact male Persian cat (3.2 kg of body weight) was referred with primary complaint of constipation. Diagnostic studies found severe constipation and megacolon. After immediate medical treatment (e.g. enema), the physical examination was performed and revealed that the unusual urethral opening was found approximately 0.5 cm ventral to the tip of the penis where a 3.5 fr tomcat catheter was easily advanced into the bladder. The case was diagnosed as hypospadias. The cat was treated with castration and medical therapy for constipation. To our best knowledge, this case is the first case report for feline hypospadias complicated with chronic constipation in Korea.

An Evaluation on the Effect of Reversed Plastic Zone on the Fatigue Crack Opening Behavior under 2-D Plane Stress (2차원 평면응력 상태에서 되풀이 소성역이 피로균열 열림 현상에 미치는 영향에 관한 연구)

  • Choi, Hyeon-Chang
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.29 no.8 s.239
    • /
    • pp.1078-1084
    • /
    • 2005
  • The relationship between fatigue crack opening behavior and the reversed plastic zone sizes is studied. An elastic-plastic finite element analysis (FEA) is performed to examine the opening behavior of fatigue crack, where the contact elements are used in the mesh of the track tip area. The smaller element size than reversed plastic zone size is used fer evaluating the distribution of reversed plastic zone. In the author's previous results the FEA could predict the crack opening level, which crack tip elements were in proportion to the theoretical reversed plastic zone size. It is found that the calculated reversed plastic zone size is related to the theoretical reversed plastic zone size and crack opening level. The calculated reversed plastic zone sizes are almost equal to the reversed plastic zone considering crack opening level obtained by experimental results. It can be possible to predict the crack opening level from the reversed plastic zone size calculated by finite element method. We find that the experimental crack opening levels correspond with the opening values of contact nodes on the calculated reversed plastic zone of finite element simulation.

Digit Recognition for Vehicle License Plate Based on Opened Enclosure (열림방향을 이용한 자동차번호판 숫자인식)

  • Zheng, Liu;Kim, Dong-Wook
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
    • /
    • v.8 no.6
    • /
    • pp.453-459
    • /
    • 2015
  • In this paper, we propose a new digit recognition method based on opened enclosure. In the proposed method, each digit is divided into two parts, an upper part and a lower part, which are based on a cutting line that is modified depending on the number of intersection points. In the simulation, the performance evaluation through the data acquisition and application of the proposed algorithm was carried out and the result was presented.

The Effect of $Cd^{2+}$ on Stomatal Apertures of Epidermal Strips in Commelina communis L. ($Cd^{2+}$이 닭의장풀의 기공개폐에 미치는 영향)

  • 이준상
    • Korean Journal of Environmental Biology
    • /
    • v.18 no.2
    • /
    • pp.263-268
    • /
    • 2000
  • The effect of $Cd^{2+}$ on stomatal apertures of epidermal strips and intact leaves in Commelina communis L. was investigated. Cadmium stimulated stomatal opening. The stomata, treated with 100 $\mu$M $Cd^{2+}$ opened to a degree of about 8.38 fm, but the stomata, treated with no cadmium opened to 3.74 ${\mu}{\textrm}{m}$. In order to show that there was no mechanical or osmotic impediment preventing the stomata in the epidermal strips, salicylic acid (SA) and abscisic acid (ABA) were used. The treatment of 100 $\mu$M SA and 1 $\mu$M ABA inhibited 14% and 28% of stomatal opening, respectively. Other heavy metals such as $Al^{3+} and Ag^{2+}$ were also used to investigate the effect of the stomatal apertures. The treatment of $Al^{3+} and Ag^{2+}$ also stimulated 19% and 41% of stomatal opening. To understand how cadmium open stomata, the effect of cadmium on the K+ influx into the epidermal strips was investigated. $Cd^{2+}$, SA, ABA inhibited 98%, 28%, 34% of K+ uptake respectively. 3-weeks old Commelina was transferred to and grown in Hoagland solution (0,5 mM $Cd^{2+}$, 10 mM $Cd^{2+}$) for 4 days and stomatal conductance were measured. The treatment of 5 mM $Cd^{2+}$ and 10 mM $Cd^{2+}$ showed about 51% and 70% inhibition of stomatal conductance, respectively Therefore, it could be concluded that stomata in epidermal strips and intact leaves behaved differently and cadmium- stimulated stomatal opening was due to the result of cadmium uptake into the epidermal strips instead of K+. [cadmium, stomata, stomatal conductance]

  • PDF

Classification of Acoustic Emission Signals for Fatigue Crack Opening and Closure by Artificial Neural Network Based on Principal Component Analysis (주성분 분석과 인공신경망을 이용한 피로균열 열림.닫힘 시 음향방출 신호분류)

  • Kim, Ki-Bok;Yoon, Dong-Jin;Jeong, Jung-Chae;Lee, Seung-Seok
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.22 no.5
    • /
    • pp.532-538
    • /
    • 2002
  • This study was performed to classify the fatigue crack opening and closure for three kinds of aluminum alloy using principal component analysis (PCA). Fatigue cycle loading test was conducted to acquire AE signals which come from different source mechanisms such as crack opening and closure, rubbing, fretting etc. To extract the significant feature from AE signal, correlation analysis was performed. Over 94% of the variance of AE parameters could accounted for the first two principal components. The results of the PCA on AE parameters showed that the first principal component was associated with the size of AE signals and the second principal component was associated with the shape of AE signals. An artificial neural network (ANN) an analysis was successfully used to classify AE signals into six classes. The ANN classifier based on PCA appeared to be a promising tool to classify AE signals for fatigue crack opening and closure.

Effect of Seeding Depth on Hypocotyl Growth, Hook Opening, and Sucrose Metabolism in Soybean (파종 심도가 콩의 하배축 생장과 Hook 열림 및 Sucrose 대사에 미치는 영향)

  • Yun, Seung-Gil;Lee, Sang-Gak;Lee, Sang-Eun;Park, So-Hyon;Huh, Kwang-Woon;Lim, Sun;Kim, Tae-Wan
    • Korean Journal of Soil Science and Fertilizer
    • /
    • v.36 no.6
    • /
    • pp.429-436
    • /
    • 2003
  • The relationship between seeding depth and apical hook opening was investigated in the hypocotyl hook of soybean (Glycine max Merr., cv. Hwanggeum). Seeds were sawn in different depths (2.5, 5.0, 7.5, and 10.0 cm). The hook opening was slowly progressed with seeding depth. Hook angle opening velocity was negatively correlated with hypocotyl growth at the significant level of P<0.01. It was also clearly observed that seeding depth was positively correlated with hypocotyl growth, suggesting the induction of hypocotyl growth by deep sawing. Futhermore, the contents of fructose and glucose in hypocotyls were about higher than in cotyledons. Both sugars in hypocotyls were highest at the emergence stage. After emergence, their levels were obviously reduced. Total soluble sugar contents continuously retained in cotyledons which were grown at 2.5 and 5.0 cm seeding depths whereas the contents in cotyledons of deep sawn soybean were extremely lowered. It seemed that sugars were actively used to cell construction during the hypocotyl elongation. The results demonstrated that apical hook opening is closely related with light signal after emergence. It implied that the delay of hook opening in deep sawn seeds was resulted from hypocotyl growth in darkness. We suggest that apical hook opening is progressed in sucrose catabolism by light.