• 제목/요약/키워드: internal materials

검색결과 3,134건 처리시간 0.032초

수박에서의 초음파 전파 특성에 관한 실험적 연구 (An Experimental Study on the Propagation Characteristics of Ultrasonic Wave in Watermelon)

  • 장경영;김만수;조한근
    • Journal of Biosystems Engineering
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    • 제23권6호
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    • pp.615-620
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    • 1998
  • The nondestructive internal quality evaluation of agricultural products has been strongly required from the needs for individual inspection. In recent, ultrasonic wave has been considered as a solution for this problem. It transmit well through most materials and can handle safely and easily. However, specially in a watermelon, it is known that general frequency band (higher than 20kHz) ultrasonic waves do not transmitted well due to severe attenuation. The objectives of this study were to find out the proper waveform and frequency of the ultrasonic waves that transmit well inside the watermelon, and to analyze the transmitted waveform in order to make clear the structure of wave propagation in watermelon. The result of several experiments showed that 2kHz shear wave was the most suitable for the detection of internal cavity in the watermelon. Also, it was found that the surface wave did not influence the directly transmitted bulk wave. These results could be a basis of application of ultrasonic wave on the evaluation of internal quality of the watermelon.

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4각 순환유동층의 수력학적 특성 (Hydrodynamic Characteristics of the Rectangular Type Circulating Fluidized Bed)

  • 현상열;이관석
    • 열처리공학회지
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    • 제10권4호
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    • pp.232-236
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    • 1997
  • A rectangular type circulating fluidized bed (CFB) with an internal nozzle and two partition walls was proposed. In this modified CFB, an internal nozzle and two slanted partition walls were additionally set in the riser. This cold mode apparatus was made of acrylic resin; the riser was 1500mm high and $1000{\times}1000mm^2$ in the cross sectional area, the internal nozzle was 200mm high and 10mm in the inner diameter, and the partition wall was 7mm thick. Glass beads of $91{\mu}m$ in the mean diameter were employed as bed materials. In the cold mode by using the proposed CFB with an internal nozzle, it was possible to change the particle hold up by changing the gas flow ratio of the nozzle to the total(Qn/Qt). It was found that the inflection point which devided the bed structure between the dense and the dilute phase in the riser varied with Qn/Qt.

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관재 하이드로 포밍에 의한 성형 공정의 실험적 연구 (Experimental Studies of the Forming Process for the Tubular Hydroforming Technology)

  • 김성태;임성언;이택근;김영석
    • 소성∙가공
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    • 제9권1호
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    • pp.35-42
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    • 2000
  • In this paper, we developed the hydroforming simulator which can apply an axial compressive force and high internal pressure to bulge a tube. Experimental dtudies have been performed to investigate the effect of each parameters such as internal pressure and axial compression stroke required for the forming of circular components. Under the improper forming conditions there were two forming failures. One was the axial buckling due to excessive axial compressive load and the other was the circumferential necking fracture due to relatively high internal pressure. A safe forming zone without any failures exists between these two extreme zones. Also the condition of forming failure such as fracture is examined throughout the theoretical analysis. This paper covers a brief overview of the mechanism of hydroforming process as well as the design of die and tools.

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Correlation between internal derangement and osteoarthrosis in the temporomandibular joint using magnetic resonance imaging

  • Song Haeng-Un;Choi Sun-Young;Koh Kwang-Joon
    • Imaging Science in Dentistry
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    • 제32권4호
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    • pp.221-225
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    • 2002
  • Purpose: To evaluate the relationship between internal derangement and osteoarthrosis in the temporomandibular joint (TMJ) using magnetic resonance imaging (MRI). Materials and Methods: One hundred and six MR images of TMJs in 53 patients were evaluated. Disc displacements and osseous changes of the TMJs were assessed. Lateral and rotational disc displacements were also evaluated on coronal images. Results: No significant differences in the frequency of osseous changes of the TMJs between disc displacement with reduction and disc displacement without reduction groups were found. The erosion of the condylar head and the sclerosis of the articular eminence were more frequent in the internal derangement group than in the no disc displacement group. The flattening was the most frequently observed osseous change of both the condylar head and articular eminence. Conclusion : The relationship between internal derangement and osteoarthrosis is obscure, but it is thought that both disorders adversely affect each other.

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병원의 실내환경 특성에 관한 연구 - 부산지역 내과병원을 중심으로 - (A Study on the Interior Characteristics of Healthcare Environment - Focused on the Internal Medicine in Busan -)

  • 황연숙;오찬옥
    • 한국실내디자인학회논문집
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    • 제30호
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    • pp.35-41
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    • 2002
  • The purpose of this study was to examine the current interior conditions of internal medicines and the patients'responses to them. Data were collected through questionnaire survey including observations and interviews. The sample consisted of 43 internal medicines in Busan. The data were analyzed by using SPSS-PC. The major findings were as follows: (1) Most of the medicines had a size of 20-50 pyung(66-165$m^2$). The preferred size of internal medicine was 30-70 Pyung. (2) The typical layout of reception room, doctor's room, and injection room was L shape. (3) The most preferred room was waiting room and the worst one was injection room. (4) Painting and tile were mostly used as interior finishing materials. The patients preferred wall papers as wall and ceiling material, and marbles as floor material. Also, the most preferred interior images were modern, western, urban, open, simple, warm and popular images.

양생직후 초기재령의 콘크리트 내부 온도와 상대습도의 측정 및 분석 (Investigation of Internal Temperature and Relative Humidity of Concrete Immediately After Mix and Placement)

  • 박철우;박영훈;박용걸
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2008년도 추계학술대회 논문집
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    • pp.1065-1068
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    • 2008
  • Concrete is still one most common construction materials even in railway structures. As structures become massive and mega-sized, the importance of early age concrete quality control becomes more significant. Among various factors, relative humidity and temperature are the primary factors governing the early age quality. Temperature raise due to cement hydration causes stress, which can develop to cracking with internal and/or external restraints. Exposure conditions including ambient temperature, humidity and wind also significantly affect the cracking behavior of early age concrete. Among many of studies on the early age concrete behavior, investigation on the variation of temperature and relative humidity internal of concrete is not common. That is in part because the difficulties in measuring the relative humidity and temperature inside the concrete. This study used a digital sensor with an appropriate logger to measure internal temperature and relative humidity. This direct measuring method is expected to provide more reliable and comprehensive data acquisition on the early age behavior of concrete.

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디젤 엔진용 캠축 소재의 금속적 특성 및 선삭 가공 특성에 관한 연구 (Turning and Metalic Characterization for CAM Shaft Materials of Diessel Engine)

  • 채왕석;김경우;김동현
    • 한국정밀공학회지
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    • 제14권7호
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    • pp.22-28
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    • 1997
  • In this paper, We have studied internal quality incluiding chemical compositions, microscopic structure and nonmetalic inclusion of test material. We have analyzed dynamic characteristics of cutting resistence and compared chip treatment of the test material. In analyzing internal quality, all of the test material have typical ferrite+pearlite structure. But, nonmetallic inclusion has oxide and sulfide inclusion has oxide and sulfide inclusion in medium carbon steel, mainly sulfide inclusion is existed in S-free cutting steel. In Ca+S-free cutting steel, calcium aluminate and sulfide complex inclusion, had low-melting point, as deformation of sulfide and oxide inclusion is existed. Machining characteristics, cutting resistence is maximum in medium carbon steel. Chip treatement are excellent in S-free cutting steel, similar to the Ca+S free cutting steel and medium carbon steel.

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쌍곡선포물선 대공간 구조물의 측벽개구율에 따른 지붕의 풍압특성 (Characteristic of Wind Pressure Distribution on the Roof of Hyperbolic Paraboloid Spatial Structures)

  • 유장열;유기표
    • 한국공간구조학회논문집
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    • 제13권1호
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    • pp.51-57
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    • 2013
  • There can be diverse causes in the destruction of a large space structure by strong wind such as characteristics of construction materials and changes in internal and external wind pressure of the structure. To evaluate the wind pressure of roof against the large space structure, wind pressure experiment is performed. However, in this wind pressure experiment, peak internal pressure coefficient is set according to the opening of the roof in Korea wind code. In this article, it was tried to identify the change of internal pressure coefficient and the characteristics of wind pressure coefficient acting on the roof by two kinds of opening on the side of the structure with Hyperbolic Paraboloid Spatial Structures roof. When analyzing internal pressure coefficient according to roof shape, it was found that minimum (52%) and maximum (30%~80%) overestimation was made comparing to partial opening type proposed in the current wind load. It is judged that evaluation according to the opening rate of the structure should be made to evaluate the internal pressure coefficient according to load.

인진청간탕(茵蔯淸肝湯)이 인체 간암세포의 혈관생성인자 발현에 미치는 영향 (The Effects of Injinchunggan-tang(Yinchenqinggan-tang) on Expression of Angiogenic Factors in HepG2 Cells)

  • 김철우;김영철;이장훈;우홍정
    • 대한한방내과학회지
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    • 제27권1호
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    • pp.138-148
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    • 2006
  • Objectives: This study was designed to investigate the effects of Injinchunggan-tang(Yinchenqinggan-tang) on expression of angiogenic factors in HepG2 cells. Materials and Methods : The mRNA expression levels and protein secretion levels of angiogenic factors were measured using quantitative RT-PCR, Western blot and ELISA assay respectively in Injinchunggan-tang-treated and untreated HepG2 cells. Results : Injinchunggan-tang(Yinchenqinggan-tang) reduced mRNA expression levels and protein secretion levels of angiogenic factors, especially VEGF, bFGF and $TGF{\beta}1$ in HepG2 cells. Conclusion: Results indicate that Injinchunggan-tang (Yinchenqinggan-tang) inhibits expression of angiogenic factors in HepG2 cells. Further, results suggest that Injinchunggan-tang (Yinchenqinggan-tang) inhibits angiogenic effects in HCC.

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와송(瓦松)이 만성 골수성 백혈병 세포주(K562)에서 세포사멸에 미치는 영향 (Effect of Orostschys japonicus A. Berger on Apoptosis in K562 Cell Lines)

  • 윤경수;김영철;이장훈;우홍정
    • 대한한방내과학회지
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    • 제27권1호
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    • pp.166-177
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    • 2006
  • Objectives : This study was performed to determine if Orostschys japonicus A. Berger has protective effects against CML in K562 cell lines. Materials and Methods : MTT assay, cell proliferation assay, Reverse transcription-polymerase reaction chain, RT-PCR, DNA fragmentation assay, Quantitative PCR were studied. Results : Orostschys japonicus A. Berger had no effects on Bax gene in K562 cell lines, but decreased Bcl-2 gene, and increased the Caspases-3 gene. This is indicate of induced apoptosis in K562 cell lines by Orostschys japonicus A. Berger. Conclusion : These results suggest that Orostschys japonicus A. Berger has effects on apatosis in K562 cell lines.

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