• 제목/요약/키워드: Dumbbell-shape

검색결과 28건 처리시간 0.022초

단섬유 끝 형상이 강화고무의 인장 특성에 미치는 영향 (Effects of Short-fiber End Shape on Tensile Properties of Reinforced Rubber)

  • 류상렬;이동주
    • 대한기계학회논문집A
    • /
    • 제25권6호
    • /
    • pp.1023-1030
    • /
    • 2001
  • The tensile properties of short nylon6 fiber reinforced NR and SBR have been investigated as functions of diameter ratio(DR), interphase condition, fiber aspect ratio(AR), and fiber content. The short-fiber(DR=3 and AR=2) reinforced SBR did not show the dilution effect for all interphase conditions. And the short-fiber(DR=3 and AR=2) reinforced NR did not show the dilution effect except for the no-coating. The better interphase condition, the lower dilution effect at same DR. The tensile moduli are significantly improved due to fiber content and diameter ratio at same interphase condition. The pull-out force increased with the DR. The better interphase condition, the higher pull-out force at same DR. It is found that the DR and AR have an important effect on tensile properties.

손상된 지오멤브레인의 응력균열 저항성 해석 (Interpretation of Stress Crack Resistance of Damaged Geomembranes)

  • 전한용;;장연수
    • 한국지반공학회:학술대회논문집
    • /
    • 한국지반공학회 2010년도 춘계 학술발표회
    • /
    • pp.305-313
    • /
    • 2010
  • HDPE smooth and textured GMs were cut into dumbbell shape and notched where depth of the notch produced a ligament thickness of 90% to 10% of the nominal thickness of the specimen at 10% interval. Yield stress and elongation were measured of those samples and plotted on Graph. Yield stress and elongation at yield point decreases gradually as the notch depth is increased. Both installations damaged and notched GMs were used to understand stress crack behavior. Intact sample were notched in such a manner that the depth of notch produced a ligament thickness of 80% of the nominal thickness of the specimen. Installation damaged samples were not notched. Stress Crack Resistance behavior was observed using NCTL Test at $50{\pm}1^{\circ}C$ at different yield stresses immerging with pH 4 and pH 12 buffer solutions. Significant difference was observed in both cases.

  • PDF

신생아의 미성숙 위 기형종 1예 (Immature Gastric Teratoma in a Neonate)

  • 박창민;김민찬;이진화;김대철
    • Journal of Gastric Cancer
    • /
    • 제3권3호
    • /
    • pp.158-160
    • /
    • 2003
  • Gastric teratoma (GT) is an exceeding rare lesion seen most often in male infants, comprising less than $1\%$ of all teratomas in children. A 2-day-old male child was preoperatively diagnosed to have gastric teratoma on ultrasonogram and abdominal computed tomography (CT). On laparotomy, Dumbbell- shape GT was located on lesser curvature of stomach and complete excision of the tumor was performed. The histological examination revealed immature teratoma of the stomach. The child is well 10 months after surgery.

  • PDF

Lowpass Filter Design For Eliminate The Harmonic Signals Using Photonic Bandgap Structure

  • Kim Jang Kwon;Kim Dong Sik;Kang Chang Soo
    • 대한전자공학회:학술대회논문집
    • /
    • 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
    • /
    • pp.19-22
    • /
    • 2004
  • The goal of this study is to realize the PBG lowpass filter using novel PBG structure modification both upper layer and ground layer. It has been designed three aperture slots of ground layer for PBG structure which the center slot shape of ground is two type, rectangular and dumbbell. This PBG LPF has the character of the broader stopband and smaller size than typical LPF. The measurement results have matched the simulated ones. It has the cutoff frequency of each 4.465GHz and 3.52GHz and at least -20dB of the signal suppression at the stopband

  • PDF

변형속도에 따른 폴라아미드 섬유 및 후크형 강섬유 보강 시멘트 복합체의 인장특성 (Tensile Properties of Polyamide Fiber and Hooked Steel Fiber Reinforced Cementitious Composites by Strain Rate)

  • 이상규;김규용;황의철;손민재;백재욱;남정수
    • 한국건축시공학회:학술대회논문집
    • /
    • 한국건축시공학회 2018년도 추계 학술논문 발표대회
    • /
    • pp.73-74
    • /
    • 2018
  • In this study, it evaluate the tensile properties of polyamide fiber reinforced cementitious composite and hooked steel fiber reinforced cementitious Composites by strain rate. Polyamide fiber reinforced cement composites (PAFRCC) and Hooked Steel Fiber Reinforced Cement Composite(HSFRCC) were fabricated. Each specimen was reinforced with 1.0 and 2.0vol% fiber. The length of the reinforced fiber was 30 mm for both fibers, and the tensile test specimen was made in dumbbell shape. As a result, the tensile strength of fiber in polyamide fiber and the mechanical bonding between fiber and matrix in hooked steel fiber are considered to be the main factors affecting tensile behavior of fiber reinforced cement composite.

  • PDF

Numerical Life Prediction Method for Fatigue Failure of Rubber-Like Material Under Repeated Loading Condition

  • Kim Ho;Kim Heon-Young
    • Journal of Mechanical Science and Technology
    • /
    • 제20권4호
    • /
    • pp.473-481
    • /
    • 2006
  • Predicting fatigue life by numerical methods was almost impossible in the field of rubber materials. One of the reasons is that there is not obvious fracture criteria caused by nonstandardization of material and excessively various way of mixing process. But, tearing energy as fracture factor can be applied to a rubber-like material regardless of different types of fillers, relative to other fracture factors and the crack growth process of rubber could be considered as the whole fatigue failure process by the existence of potential defects in industrial rubber components. This characteristic of fatigue failure could make it possible to predict the fatigue life of rubber components in theoretical way. FESEM photographs of the surface of industrial rubber components were analyzed for verifying the existence and distribution of potential defects. For the prediction of fatigue life, theoretical way of evaluating tearing energy for the general shape of test-piece was proposed. Also, algebraic expression for the prediction of fatigue life was derived from the rough cut growth rate equation and verified by comparing with experimental fatigue lives of dumbbell fatigue specimen in various loading condition.

Early Selection of Double Flowers Based on Cotyledon Shape in Cut Stock (Matthiola incana L.) Flowers

  • Irani, Sepideh Famil;Arab, Mostafa
    • 원예과학기술지
    • /
    • 제35권2호
    • /
    • pp.265-275
    • /
    • 2017
  • Selection of double-flowered plants at the seedling stage is one of the main purposes of stock breeding programs. Eight stock cultivars of Matthiola incana L. named 'Nobel', 'Cinderella', 'Pacific', 'Avalanche', 'Midblue', 'Lavender', 'Goddess' and 'Esfahan', with different percentage of double-flowered plants were used for examining the relationship with three morphological types of cotyledons. The results of a chi-square test indicated that in heart-shaped (HC) and cup-shaped cotyledon (CC) populations, the number of plants with double flowers was much more than that of single flowers and CC seedlings rarely produced single flowers. Therefore, increasing the number of CC seedlings can improve the percentage of double flowers. The highest and lowest numbers of CC seedling were observed in high double and single flower cultivars, respectively. Single flower cultivars showed the maximum count of dumbbell-shaped cotyledons. Chromosome pairing of these cultivars was evaluated using the squash technique. Aneuploid cells were found in 'Nobel' and 'Goddess' cultivars, which showed the highest percentage of CC seedling. Based on morphological measurements, the highest value of inflorescence size was observed in the seedlings with cup-shaped cotyledons.

The Characterization of Borohydride-Stabilized Nanosilvers in Laponite Sol Using 1H NMR: Its Ligand Exchange Reactions with MUA and TOP

  • Seo, Jae-Seok;Son, Dong-Min;Lee, Han-Na;Kim, Jee-Kwang;Kim, You-Hyuk
    • Bulletin of the Korean Chemical Society
    • /
    • 제30권11호
    • /
    • pp.2651-2654
    • /
    • 2009
  • In borohydride-protected nanosilvers in laponite sol, the silver particles aggregate to form short chains and a dumbbell shape. The $^{1}H$ NMR measurements in this study represent, to our knowledge, the first observation of proton resonances of borohydride-protected nanosilvers in aqueous solution. Borohydride on nanosilver can be exchanged with 11-mercaptoundecanoic acid (MUA) or trioctylphosphine (TOP). Transmission electron microscopy and UV-Vis spectroscopy data show that the number of aggregated silver nanoparticles decreases upon addition of aforementioned ligands due to the formation of silver MPCs (monolayer-protected clusters). Adsorption of MUA or TOP on nanosilver is confirmed through the observation of broad proton resonances of MPCs in $^{1}H$ NMR spectra.

Diversity and origin of bottle gourd, Lagenaria

  • Yuasa, Hiroshi
    • 한국자원식물학회:학술대회논문집
    • /
    • 한국자원식물학회 2002년도 심포지엄
    • /
    • pp.96-97
    • /
    • 2002
  • Bottle gourd, Lagenaria siceraria, is one of the oldest cultivated plants. To bigin with, its fruit was used as a complete liquid bottle or container. It was a very widespread cultivated plant in prehistoric times, for example (there) is a report from Peru as early as between 13,000 B.C and 11,000 B.C. The dug-out finds in Japan proved to be about 95,000 years old according to the /sup 14/C analysis. The bottle grourd was the most important plant before the invention of pottery in many areas of Asia, New Guinea, Polynesia, America, and Africa. I would like to suggest that there should be "The Bottle Gourd Age" prior to the Pottery Age. Bottle gourds are also used for various purposes such as food, masks, pipes, musical instruments, medicine, symbols, artistic products and also as penis-sheaths of men's attire. Their purposes number more than 220 including 70 varienties of containers or bottles. I consider that its utilization should be called a culture, as it were, "The gourd culture." The shape and the size of the fruit of bottle gourd have a larger variety than those of any other plant. As for the size, it is reported that they range from those that are shorter than 3cm to those that are ovoid and longer than 60cm in diameter. With regard to the shape of its fruit, the bottle gourd can be classified into 7 groups and even more than 30 races, considering the difference of the size. The seeds are so variable without two horn-like projections, with smooth surface or longitudinalines, white or brown, with smooth corky margin. Generally, it seems that there is no correlation between seem shape and fruit shape. My study shows that the seeds of gourd. My study shows that the seeds of gourd in Asia are so simple in shape and in color except for the size. But the seeds of those in Africa are various and seem to be beyond the confines. Explaining the great diversity of the seeds of those in Africa therefore, they appear to have no correlation among the types of fruit of the bottle gourd with African origin. It might be supposed that another 4 wild Lagenaria spp. distribute only in Africa. The intraspecies hybrid is confirmed between the bottle gourd, Lagenaria siceraria, and wild L. spehaerica. And Fl hybrid is sterile: it has no fertility. However, even though the shapes of the fruit and the seeds are different, they can cross with each other. Moreover, their hybrids grow up to be extremely vigorous and have normal fertility. Fruit shapes of Fl plants are similar to those of their parents, if they have the same character. Whereas, the fruit shape often became different from each other when the cross occurs between those with different fruit shapes. It is shown that dumbbell shapes, HYOTAN in Japanese, is recessive while its bitterness is dominant. Thus the character of F2 hybrids Is segregative. I'll give further particulars of the heredity of the groud in my lecture.

  • PDF

조직내 및 배야기내 자유생활아메바의 전자현미경적 비교연구 (Ultrastructural observation of Naegleyiu fowleri trophozoite in mouse brain and axonic culture)

  • 유재숙;소진탁임경일
    • Parasites, Hosts and Diseases
    • /
    • 제22권2호
    • /
    • pp.259-266
    • /
    • 1984
  • 원발성 아메바성 뇌수막염 (primary amoebic rneningoencephalitis; PAM)을 일으키는 자유생황아메바인 Svaegleria few입번를 사용하여 액체배지에서 무균적으로 배양된 영양형과 실험적으로 감염시켜 얻은 마우스 뇌조직에 존재하는 영 양형의 미세구조를 전자현미경을 이용하여 비교 관찰한 결과 다음과 같은 성적을 얻었다. 1. 마우스 뇌 조직내의 영양형은 다소 등근 모양인데 반해 액체배지에서 무균배양하여 엎은 영양형은 불규칙한 모양을 보였다. 2. 배 양기에서 얻은 아메바 세포질내 mitochondria 는 난원형, 구형 및 원통형 등 형태가 다양한데 마우스 뇌 조직내의 아메바에서는 이러한 형태 이외에 아령 모양이 특이하게 있었고 배양기내 아메바의 mitochondr심는 진하게 염색되나 마우스 뇌 조직내의 아메바에서 는 진한 것과 흐린 것이 모두 있었다. 3. 조면세포질내세망(rER)의 형태에 있어 마우스뇌조직내 아메바에서는 세관(microtubule)모양인데 비해 배 양기내 아에 바에서는 세관모양 이외에도 소낭(vesiole) 모양이 관찰된다. Ribosome은 배양기내 아메바에서는 free ribosome이 많은 반면 마우스 뇌조직내 아메바에서는 polysome이 많았다. 4. 배양기내 아메바에서는 내용물이 없는 액포(vacuole)가 많고 그 안에 미엘린양 구조가 존재함을 보앗다. 이것으로 아메바는 마우스 뇌조직내에서 강한 식작용을 나타냄을 알 수 있다. 5. Naegleria fowleri에 감염된 마우스 뇌조직은 괴사가 심하였다. 침윤된 염증세포로 다핵백혈구가 많았고, 아메바는 혈관 주위에 많았다.

  • PDF