• 제목/요약/키워드: Disk shape

검색결과 353건 처리시간 0.027초

High Frequency Properties of Patterned Fe-Al-O Thin Films

  • N.D. Ha;Park, B.C.;B.K. Min;Kim, C.G.;Kim, C.O.
    • 한국자기학회:학술대회 개요집
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    • 한국자기학회 2003년도 하계학술연구발표회 및 한.일 공동심포지엄
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    • pp.194-194
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    • 2003
  • As a result of the recent miniaturization an enhancement in the performance of thin film inductors and thin film transformers, there are increased demands for the thin films with high magnetic permeability in the high frequency range, high saturation magnetization, in high electrical resistivity, and low coercive force. In order to improve high frequency properties, we will investigate anisotropy field by shape and size of pattern. The Fe-Al-O thin films of 16mm and 1 $\mu\textrm{m}$ thickness were deposited on Si wafer, using RF magnetron reactive sputtering technique with the mixture of argon and oxygen gases. The fabricating conditions are obtained in the working partial pressure of 2mTorr, O$_2$ partial pressure of 5%, input power of 400W, and Al pellets on an Fe disk with purity of 99,9%. Magnetic properties of the continuous films as followed: the 4$\pi$M$\_$s/ of 19.4kG, H$\_$c/ of 0.6Oe, H$\_$k/ of 6.0Oe and effective permeability of 2500 up to 100㎒ were obtained. In this work, we expect to enhance effect of magnetic anisotropy on patterned of Fe-Al-O thin films.

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Multiepoch Optical Images of IRC+10216 Tell about the Central Star and the Adjacent Environment

  • Kim, Hyosun;Lee, Ho-Gyu;Ohyama, Youichi;Kim, Ji Hoon;Scicluna, Peter;Chu, You-Hua;Mauron, Nicolas;Ueta, Toshiya
    • 천문학회보
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    • 제46권2호
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    • pp.36.1-37
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    • 2021
  • Six images of IRC+10216 taken by the Hubble Space Telescope at three epochs in 2001, 2011, and 2016 are compared in the rest frame of the central carbon star. An accurate astrometry has been achieved with the help of Gaia Data Release 2. The positions of the carbon star in the individual epochs are determined using its known proper motion, defining the rest frame of the star. In 2016, a local brightness peak with compact and red nature is detected at the stellar position. A comparison of the color maps between 2016 and 2011 epochs reveals that the reddest spot moved along with the star, suggesting a possibility of its being the dusty material surrounding the carbon star. Relatively red, ambient region is distributed in an Ω shape and well corresponds to the dusty disk previously suggested based on near-infrared polarization observations. In a larger scale, differential proper motion of multiple ring-like pattern in the rest frame of the star is used to derive the average expansion velocity of transverse wind components, resulting in ~12.5 km s-1 (d/123 pc), where d is the distance to IRC+10216. Three dimensional geometry is implied from its comparison with the line-of-sight wind velocity determined from half-widths of submillimeter emission line profiles of abundant molecules. Uneven temporal variations in brightness for different searchlight beams and anisotropic distribution of extended halo are revisited in the context of the stellar light illumination through a porous envelope with postulated longer-term variations for a period of 10 years.

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Seed and seed coat morphology in monotypic and endemic genera of Korean angiosperms

  • Se-Moon AHN;Hye-Rin KIM;Kweon HEO
    • 식물분류학회지
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    • 제53권2호
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    • pp.102-109
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    • 2023
  • The basic information of ovule and seed characteristics was investigated for five monotypic and endemic genera in the Korean peninsula as categorized by the Flora of Korea category. The carpels and seeds were sectioned with a rotary microtome. Mature seeds were coated with platinum using an ion sputter and observed using a scanning electron microscope. As a result, Abeliophyllum was found to be anatropous and a unitegmic ovule, with a slightly colliculate seed surface and exotestal seed coat type. The ovule of Coreanomecon was anatropous and bitegmic, having a distinct echinate seed surface, and exo-endotestal seed coat type with a prismatic crystal in the mesotesta. The ovule of Hanabusaya was anatropous and a unitegmic, with a long reticulate seed surface sculpture, and distinct exotestal seed coat type. In addition, a wing developed at the opposite side of the raphe bundle. Megaleranthis was an anatropous and bitegmic ovule, having a small pentagonal disk shape, a concave seed surface and exotestal seed coat type. Finally, Pentactina was also anatropous and a unitegmic ovule, reticulate seed sculpture, and endotestal seed coat type. These data will be proving to be a source of good information for securing bio-sovereignty in the near future.

착생에 따른 담쟁이덩굴 흡착근 표피조직의 변화 (Epidermal Changes of the Adhesive Disks During Wall Attachment in Parthenocissus tricuspidata)

  • 김정하;김인선
    • Applied Microscopy
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    • 제37권2호
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    • pp.83-91
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    • 2007
  • 식물체는 기관에 따라 조직 및 세포의 종류와 배열이 분화 초기단계에 이미 정해져 특징적인 형태를 갖게 되나 여러 요인에 의해 변형되기도 한다. 줄기에 덩굴손이 변형되어 부정근인 흡착근을 형성하는 담쟁이덩굴은 벽면 등의 피착면에 착생하는 식물로 이들의 흡착근은 특징적인 구조를 지닌다. 본 연구에서는 착생에 따른 담쟁이덩굴의 흡착근 표피조직의 분화양상을 전자현미경적으로 추적하여 연구하였다. 흡착근은 분화 초기에 경정단 분열조직으로부터 포에 둘러싸여 발달한다. 초기의 어린 흡착근은 곤봉형으로 상 하피 구별이 되지 않으나 활발히 생장하는 흡착근은 구형으로 상 하피가 뚜렷이 분화된다. 최외층의 표피는 장방형의 세포로 구성되며 이들 표피세포는 세포벽에 얇은 각피층을 지닌다. 착생 전 흡착근은 볼록한 평철형이 되고 표피세포내 액포에는 전자밀도가 매우 높은 물질이 다량 축적된다. 착생 직전 및 직후 흡착근의 상 하피조직은 빠르게 변형되어 액포에 축적된 물질이 분비되면서 피착면에 더욱 밀착되고 수분이 소실된 흡착근은 세포사멸의 과정을 거친다. 이 시기 하피조직에서의 변화는 상피조직에 비해 급격히 일어나며, 분비물질은 벽면에 강력히 흡착되어 착생의 기능을 수행하게 된다. 특히 착생을 전후로 급격한 하피조직의 변화가 일어나 흡착근 하피조직의 외곽면이 먼저 피착면에 접촉하고 전자밀도가 높은 물질이 분비되어 오목한 상태를 유지하던 중앙부위도 물질이 분비되면서 흡착근 전체가 부착되게 된다. 즉, 전자밀도가 높은 물질의 분비와 수분소실에 의한 흡착근의 피착면으로의 밀착 등이 담쟁이덩굴 흡착근의 착생에 매우 중요한 역할을 하는 것으로 추정된다. 매년 이와 같은 방법으로 흡착근은 분화 초기단계에서부터 노화에 이르기까지 여러 단계를 거치며 신속한 형태적, 구조적 변화를 수반하면서 강력한 착생기능을 수행하게 된다.토끼 면역항체를 선모충유충 조직항원에 반응시켰을 때 충체의 표피와 기저층 그리고 EIM 및 stichocyte의 ${\alpha}_0\;{\alpha}_1$ 과립에 황금입자가 표지되었다. 따라서 1일 동안 배설되는 분비배설항원은 선모충 유충의 표피와 stichocyte의 ${\alpha}_0\;{\alpha}_1$ 과립에서 유도되는 반면에 3일 동안 배설되는 분비배설항원은 표피와 stichocyte의 ${\alpha}_0$ 과립에서 유도되고, 선모충유충 감염후 1주, 4주에 실험쥐에서 형성되는 감염항체는 선모충의 표피와 기저층 그리고 EIM에서 분비되는 항원에 의하여 생성된다. 이상의 결과로 선모충의 분비배설항원과 감염항원은 선모충 유충의 표피와 EIM및 stichocyte의 ${\alpha}_0\;{\alpha}_1$ 과립에서 유도되며 이들은 45 kDa 단백을 포함하고 있는 것으로 생각된다.성하고 있는 세포들에는 세포질이 어두운 세포와 밝은 세포가 있었으며, 세포질내에는 전자밀도가 높은 분비과립이 관찰되었다. 전체적인 특징은 눈물샘분비세포 중 장액세포의 것과 비슷하였으나, 과립의 크기는 작았다. 분비관을 구성하는 세포들 사이에도 연접복합체가 매우 잘 발달되어 있었다. 샘포에서 사이관으로 이행되는 곳에서도 샘포세포와 사이관세포 사이에서도 연접복합체가 관찰되었다. 분비관세포의 분비과립 가운데는 중심부분에 전자밀도가 더 높은 중심을 가진 다른 모양의 과립이 관찰되기도 하였다. 의해 사망한 환자는 없었다. 결 론: 자궁경부암 환자에 항암화학요법과 동시에 외부 방사선조사와 고선량률의 강내조사를 시행한 결과 독성이 심하지 않고 국소제어율과 단기 생존율이 양호하여 안전하고 효율적인 치료방법으로 생각된다. 그러나 장기 생존율과

판상형 충전제의 함량과 배향에 따른 PP복합체의 열팽창계수 영향 연구 (Empirical Study on Effects of Disk Shape Filler Content and Orientation on Thermal Expansion Coefficient of PP Composites)

  • 이용현;정선경;황효연;이승구;이기윤
    • 폴리머
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    • 제36권3호
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    • pp.281-286
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    • 2012
  • 두 가지의 종횡비(${\rho}_{\alpha}=a_1/a_3$ and ${\rho}_{\beta}=a_1/a_2$)에 의해 특징지어진 3차원 타원체($a_1$ > $a_2$ > $a_3$)를 사용하여 polypropylene 복합체의 판상형 충전제 함량과 방향이 열팽창률에 미치는 영향에 대해 실험적인 연구를 수행하였다. 측정된 실험적인 값은 Lee와 그의 연구자들이 제안한 이론적인 모델에 의한 계산 값과 비교분석되었다. 판상형 충전제로는 운모와 탈크가 사용되었다. 실험 결과로 운모의 경우 종횡비는 ${\rho}_{\alpha}=13.5$, ${\rho}_{\beta}=1.8$이 사용되어, 20 wt% 함량일 때 ${\alpha}_{11}/{\alpha}_m$는 약 0.56으로 감소하였으나, ${\alpha}_{33}/{\alpha}_m$는 오히려 1.018로 증가함을 보였다. 탈크의 경우의 종횡비는 ${\rho}_{\alpha}=3.7$, ${\rho}_{\beta}=1.4$이었고 ${\alpha}_{11}/{\alpha}_m$는 0.63으로 감소하였다. 결국 운모와 탈크 모두 그 함량증가에 따라 종단방향과 횡단방향에서 열팽창률은 감소하였으나 수직방향에서는 초기 낮은 충전제 함량에서는 오히려 증가하는 경향을 보였다.

작물 흡수를 고려한 3차원 토양수분 분포 모델 개발을 통한 최적 점적 관개 연구 (A Numerical Model of Three-dimensional Soil Water Distribution for Drip Irrigation Management under Cropped Conditions)

  • 권재필;김승현;류순호;노희명
    • Applied Biological Chemistry
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    • 제43권2호
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    • pp.116-123
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    • 2000
  • 작물이 자라는 토양에서 점적 관개에 의해 일어나는 토양 수분의 분포와 이동을 3차원 직교 좌표계로 예측할 수 있는 수학적 모델을 개발하였다. 모델은 지면 증발과 증산을 고려하였으며, 이들의 계절적 현화와 하루 중의 시간변화 뿐 아니라 작물 뿌리의 성장 및 뿌리의 토양 중 분포형태도 고려하였다. 모델의 해는 block centered grid system등을 적용하여 Crank-Nicolson법과 Gauss-Seidel 반복법을 사용하여 구하였다. 모델은 실험을 통해 검증하였으며, 점적 관개의 특성을 알기 위하여 모델을 이용한 컴퓨터 모사를 실시하였고, 본 연구의 조건으로부터 다음의 결과를 얻었다. (1) 관수된 물은 점적기에서 멀어짐에 따라 그 유속이 크게 감소하였고, 관수 시간이 증가함에 따라 습윤구역의 크기가 증가하는 속도도 급격히 감소하였다. (2) 1점 관수의 경우 습윤구역은 수평 방향보다는 수직 방향으로 더 깊이까지 도달하였다. (3) 본 연구조건에서 물이용 효율은 지하 25cm지점의 4점 관수가 가장 좋았으며, 지표면 1점 관수보다 증산량은 10% 증가, 지면 증발량은 20% 감소하였다. (4) disk tension infiltrometer에 의한 토양의 수분보유도 함수는 토양수분 압출에 의한 젖음 곡선과는 상당한 차이를 나타내는 것도 알 수 있었다.

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척추 전방전위증의 전산화 단층촬영 소견 : 협부형과 퇴행형의 비교 (CT Study of Spondylolisthesis Comparison Between Isthmic and Degenerative Type)

  • 이종덕;변재영
    • Journal of Acupuncture Research
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    • 제17권4호
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    • pp.79-87
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    • 2000
  • Objectives : To evaluate the findings useful for differential diagnosis and associated abnormaiities of isthmic spondylolisthesis and degenerative spondylolisthesis on CT. Materials and methods : We reviewed retrospectively the CT images of 65 patients who were diagnosed spondylolisthesis during 3 years period. Our technique was 5mm slices at 5mm intervals with gantry angle to parallel the interspaces. Also reformatted sagittal views were taken. 41 patients were isthmic spondylolisthesis and 24 patients were degenerative spondylolisthesis. Resuits : Isthmic spondylolisthesis. 1. Isthmic type was more common at L5-S1. 2. The degree of anterior displacement was grade I and II. 3. The plane of defect was more horizontal than the usual facet joint. 4. The defect had an irregular shape. 5. Medial aspect of bone just anterior to defect had a small round prominence. 6. Anteroposterior elongation of the spinal canal was common. 7. Pseudobulging disk was common. 8. The most common associated abnormality was a HNP at the upper level of the defect. Degenerative spondylolisthesis. 1. Degenerative type was more common at L4-5. 2. The degree of anterior disptacement was grade I and II. 3. The Plane of facet joint was oriented obliquely instead of horizontally. 4. The posterior facet(inferior facet of superior vertebra) was anteriorly displaced. 5. Bony spur of the posterior portion of anterior facet was seen. 6. The facet joints often contain gas(vaccum phenomenum). 7. The most common associated abnormality was a HNP at the level of the displacement. Conclusions : CT is a highly accurate and most sensitive technique for recognition, differential diagnosis of isthmic and degenerative types and the detection of associated abnormalities.

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Biomechanical Evaluation of the Neck and Shoulder When Using Pillows with Various Inner Materials

  • Kim, Jung-Yong;Park, Ji-Soo;Park, Dae-Eun
    • 대한인간공학회지
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    • 제30권2호
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    • pp.339-347
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    • 2011
  • Objective: The purpose of this study was to evaluate of various material of pillows by using biomechanical variables such as the cervical stability, head pressure distribution, and muscle activity. Method: Eight subjects participated in the experiment. Three different materials such as polyester sponge, memory foam and the buckwheat shell used for Korean traditional pillow were tested. Electro-goniometer, six channels of electromyography(EMG), ten channels of the head pressure sensors were used to measure the biomechanical responses. Surface electrodes were attached to the right/left semispinals capitis(RSC, LSC), the right/left sternocleidomastoid(RSM, LSM), the right/left upper trapezius(RUT, LUT). The cervical stability was evaluated by the angle deviated from the standing neck position. The head pressure distribution was evaluated by the pressure per unit area recorded on the sensors and the intensity of peak pressure. Electromyography(EMG) data were analyzed by using root mean square(RMS) and mean power frequency(MPF). Results: The buckwheat shell material showed a higher stability in the cervical spine then the other pillows during spine position. In terms of head pressure distribution, the memory form indicated the lowest pressure at supine position, buckwheat shell material indicated the lowest pressure during lying down to side, and polyester cushion recorded the highest pressure at all postures. Conclusion: The buckwheat shell material has a biomechanical advantage to maintain a healthy neck angle and reduce the pressure on the head, which means the buckwheat shell is a potential material for ergonomic pillow design. The pillow with memory form showed second best biomechanical performance in this study. Application: The shape of the buckwheat shell pillow and the characteristics of materials can be used to design the pillow preventing neck pain and cervical disk problems.

The effect of nano-sized starting materials and excess amount of Bi on the dielectric/piezoelectric properties of 0.94[(BixNa0.5)TiO3]-0.06[BaTiO3] lead free piezoelectric ceramics

  • Khansur, Neamul Hayet;Ur, Soon-Chul;Yoon, Man-Soon
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 2009년도 추계학술발표대회
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    • pp.31.1-31.1
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    • 2009
  • In an approach to acclimate ourselves torecent ecological consciousness trend, a lead-free piezoelectric material, bismuth sodium titanate (abbreviated as BNT) based bismuth sodium barium titanate (abbreviated as BNT-BT), was considered as an environment-friendly alternative for a lead based piezoelectric system. Ceramic specimens of0.94[(BixNa0.5)TiO3]-0.06[BaTiO3] (x = 0.500~0.515) compositions were prepared by a modified mixed oxide method. To increase the chemical homogeneity andre action activity, high energy mechanical milling machine and pre-milled nanosized powder has been used. In this method (BixNa0.5)TiO3 (x=0.500~0.515) andBaTiO3 were prepared separately from pre-milled constituent materials at low calcination temperature and then separately prepared BNTX (X=1, 2, 3 and 4) and BT were mixed by high energy mechanical milling machine. Without further calcination step the mixed powders were pressed into disk shape and sintered at $1110^{\circ}C$. Microstructures, phase structures and electrical properties of the ceramic specimens were systematically investigated. Highly dense ceramic specimens with homogenous grains were prepared in spite of relatively low sintering temperature. Phase structures were not significantly influenced by the excess amount Bi. Large variation on the piezoelectric and dielectric properties was detected at relative high excess Bi amounts. When $x{\leq}0.505$, the specimens exhibit insignificant variation in piezoelectric and dielectric constant though depolarization temperature is found to be decreased. Considerable amount of decrease in piezoelectric and dielectric properties are observed with higher excess of Bi amounts ($x{\geq}0.505$). This research indicates the advantages of high energy mechanical milling and importance of proper maintenance of Bi stoichiometry.

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가토에서 하악골 신장술이 악관절에 미치는 영향 (THE CHANGE OF THE TEMPOROMANDIBULAR JOINT AFTER EXPERIMENTAL DISTRACTION OF MANDIBULAR RAMUS IN RABBIT)

  • 임승규;김철환;김경욱
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • 제34권5호
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    • pp.543-549
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    • 2008
  • Distraction osteogenesis is a commonly used technique for mandibular lengthening, but changes in the temporomandibular joint(TMJ) have not been well documented. The TMJ is one of the most complex joint in the body and is composed of a fibrous surface layer, a proliferative zone, hypertrophic cartilage, and bone. The shape and role of the TMJ change and modify during a person's life-time. Possible complications that can arise after mandibular distraction include failure of the formation, failure of callus, infection, disturbance of TMJ and of occlusion. However, there are only a few reports on changes in the TMJ as a result of distraction osteogenesis. Hence, the goal of this study was to evaluate the change of the TMJ after experimental distraction of mandibular ramus in rabbit. We studied histological changes of mandibular condyle, articular disk and retrodiscal tissue, and also examined the collagen I gene expression and MMP-1 gene expression. The results were as follows. 1. In the histological staining, experimental condylar surface showed more thick fibrous articular layer and proliferative layer, compared with the control condyle and experimental articular disc showed thick and dense collagen fibers compared with the control disc. 2. In the collagen I and MMP-1 gene RT-PCR analysis, experimental discs showed increased collagen I expression compared with the control disc, while MMP-1 gene expression was decreased compared with the control disc. The retrodiscal tissue was almost equal expressions of the collagen I and MMP-1 genes compared with the control retrodiscal tissue. These findings suggest that histological and biomolecular changes occur in condyles and discs after unilateral mandibular distraction osteogenesis.