• Title/Summary/Keyword: Fine Structure

Search Result 1,724, Processing Time 0.037 seconds

Crystal Structure of $TiO_2-SnO_2$ Fine Powders Prepared by Coprecipitation (공침법에 의해 제조된 $TiO_2-SnO_2$ 미분말의 결정구조)

  • 이종흔;박순자
    • Journal of the Korean Ceramic Society
    • /
    • v.30 no.9
    • /
    • pp.740-746
    • /
    • 1993
  • TiO2-SnO2 fine powders prepared by coprecipitation from TiCl4-SnCl4 aqueous solution, and their crystal structures were studied. All the TiO2-SnO2 fine powders calcined at 180~$700^{\circ}C$ showed the complete solid solution between TiO2(rutile structure) and SnO2(rutile structure). This crystal structure of TiO2-SnO2 powders is thought to be originated mainly from the heterogeneous nucleation of Ti-hydroxde on the Sn-hydroxide with coherent structure.

  • PDF

Prediction of Bow Flare Impact Pressure and Its Application to Ship Structure Design - Container Ship and PCC - (선수 플레어 충격압력 추정과 구조설계에의 응용 - 콘테이너선과 자동차 운반선 -)

  • 김용직;신기석;신찬호;강점문;김만수;김성찬;오수관;임채환;김대헌
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.40 no.3
    • /
    • pp.29-36
    • /
    • 2003
  • In rough seas, bow-flare regions of the fine ships (container ship and PCC) are subject to high impact pressures due to the bow-flare slamming. And many ships suffer structural damages in that region, even though they were built under the bow structure strengthening rules of the ship classes. So, a new design method for bow-flare structure is highly required. In this paper, a new prediction method of the bow-flare impact pressure (in terms of equivalent static pressure) acting on the fine ships' bow is presented. This method is based on the 11 fine ships' damage analysis and the mechanisms of water entry impact and breaking wave impact. Calculation results of the bow-flare impact pressure and the shell plate thickness are shown and discussed. Through the example calculations, it was found that the present method is useful for the structure design of the fine ships' bow.

A Study on the Fine Structure of the Marine Diatoms of Korean Coastal Waters - Genus Thalassiosira 3

  • Lee, Jin-Hwan;Park, Joon-Sang
    • ALGAE
    • /
    • v.23 no.3
    • /
    • pp.187-199
    • /
    • 2008
  • A study on the fine structure of the marine diatom Thalassiosira has been carried out during the periods from January 2007 to March 2008 in Korean coastal waters. As the third series of the Thalassiosira species, a fine structure, description, distribution and taxonomic remarks of the six Thalassiosira species were observed by means of light microscope and scanning electron microscope. The critical features of Thalassiosira species were a shape of external tubes of marginal strutted processes and labiate process. Six species showed each different shape of external tubes, marginal strutted processes and labiate process. The shape of external tube was divided into five types: T shape of Thalassiosira curviseriata, small-rounded shape of T. lundiana, double-layer form and flame shape of T. nordenskioeldii, tulip shape of T. punctigera and tooth-shape of T. tenera. This external character may be able to key character for positive identification of the Thalassiosira species. Of these Thalassiosira lundiana, T. minuscula and T. tenera were new records for Korean coastal waters.

The influence of fine particle migration on pore structure of overlying ballast under cyclic loading

  • Yu Ding;Yu Jia;Zhongling Zong;Xuan Wang;Jiasheng Zhang;Min Ni
    • Geomechanics and Engineering
    • /
    • v.35 no.6
    • /
    • pp.627-636
    • /
    • 2023
  • The essence of subgrade mud pumping under train load is the migration of fine particles in subgrade soil. The migration of fine particles will change the pore structure of overlying ballast, thus affecting the mechanical properties and hydraulic properties of ballast layer. It is of great theoretical significance and engineering value to study the effect of fine particle migration on the pore structure of ballast layer under cyclic loading. In this paper, a tailor-made subgrade mud pumping test model and an X-ray computed tomography (CT) scanning equipment were used to study the influence of migration of fine particles in subgrade soil on the pore parameters (plane porosity, volume porosity, pore distribution and pore connectivity) of overlying ballast under cyclic loading. The results show that the compression of ballast pores and the blockage of migrated fine particles make the porosity of ballast layer decreases gradually. And the percentage of small pores in ballast layer increases, while the percentage of large pores decreases; the connectivity of pores also gradually decreases. Based on the test results, an empirical model of ballast porosity evolution under cyclic loading is established and verified.

Effects of Fine-slits for High Transmittance in MVA-mode LCD

  • Jung, Moo-Sung;Kim, Dae-Woo;Won, Tae-Young;Yoon, Hyung-Jin;Lee, Cheol-Soo;Yoon, Suk-In;Yoon, Sang-Ho
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 2005.07a
    • /
    • pp.443-445
    • /
    • 2005
  • In this paper, we propose an MVA mode cell structure with improved optical characteristics. Our MVA cell has an electrode with fine-slits. Optical characteristics of our proposed structure were compared with those without fine-slits. Moreover, we varied the interval as well as the widths of fine-slits in order to appreciate the effect of fine-slits. Optical characteristics of these cells were calculated with 3DFEM solver, TechWiz LCD. It was confirmed that the transmittance can be improved by more than 7% with fine-slits.

  • PDF

Fine Structure of the Cutaneous Pigments in the Black Widow Spider, Latrodectus mactans (검은과부거미 (Latrodectus mactans) 피부 색소의 미세구조에 관한 연구)

  • Moon, Myung-Jin
    • Applied Microscopy
    • /
    • v.28 no.4
    • /
    • pp.503-512
    • /
    • 1998
  • Fine structure of the cutaneous pigments in the black widow spider, Latrodectus mactans are studied with light and electron microscopes. The cutaneous pigments are only observed in epidermal layer just beneath the cuticle. These pigments are compactly distributed around the spinnerets which located at caudal area of the abdomen. According to the fine structural characteristics of the pigment granules, two main types of guanine pigment granules-carotenoid vesicles and reflecting platelets - are observed in the cytoplasm of the epidermal cells. Morphological features of these pigment granules are characterized as the electron dense carotenoid vesicles and the electron lucent reflecting platelets. Marginal electron density of the carotenoid vesicle is different from that of internal region, whereas the reflecting platelets have laminated crystalline granules. Typiral structures of these pigment granules are very similar to those of invertebrate's chromatophores, especially erythrophores and iridophores. Moreover differentiation of these pigment granules are also originated from the small vesicles of Golgi complexes similarly to those of cutaneous chromatophores.

  • PDF

Multi-Scaling Models of TCP/IP and Sub-Frame VBR Video Traffic

  • Erramilli, Ashok;Narayan, Onuttom;Neidhardt, Arnold;Saniee, Iraj
    • Journal of Communications and Networks
    • /
    • v.3 no.4
    • /
    • pp.383-395
    • /
    • 2001
  • Recent measurement and simulation studies have revealed that wide area network traffic displays complex statistical characteristics-possibly multifractal scaling-on fine timescales, in addition to the well-known properly of self-similar scaling on coarser timescales. In this paper we investigate the performance and network engineering significance of these fine timescale features using measured TCP anti MPEG2 video traces, queueing simulations and analytical arguments. We demonstrate that the fine timescale features can affect performance substantially at low and intermediate utilizations, while the longer timescale self-similarity is important at intermediate and high utilizations. We relate the fine timescale structure in the measured TCP traces to flow controls, and show that UDP traffic-which is not flow controlled-lacks such fine timescale structure. Likewise we relate the fine timescale structure in video MPEG2 traces to sub-frame encoding. We show that it is possibly to construct a relatively parsimonious multi-fractal cascade model of fine timescale features that matches the queueing performance of both the TCP and video traces. We outline an analytical method ta estimate performance for traffic that is self-similar on coarse timescales and multi-fractal on fine timescales, and show that the engineering problem of setting safe operating points for planning or admission controls can be significantly influenced by fine timescale fluctuations in network traffic. The work reported here can be used to model the relevant characteristics of wide area traffic across a full range of engineering timescales, and can be the basis of more accurate network performance analysis and engineering.

  • PDF

A Fine Manipulator with Compliance for Wafer Probing System (컴플라이언스를 갖는 웨이퍼 탐침 시스템용 미동 매니퓰레이터)

  • Choi, Kee-Bong;Kim, Soo-Hyun;Kwak, Yoon Keun
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.14 no.9
    • /
    • pp.68-79
    • /
    • 1997
  • A six DOF fine manipulator based on magnetic levitation is developed. Since most of magnetic levitation system are inherently unstable, a proposed magnetically levitated fine manipulator is implemented by use of an antagonistic structure to increase stability. From mathematical modeling and experiment, the equations of motion are derived. In addition, a six DOF sensing system is implemented by use of three 2-axis PSD sensors. A model reference-$H_{\infty}$ controller is applied to the system for the position control, In application of the fine manipulator, a wafer probing system is proposed to identify nonfunctional circuts. The probing system requires compliance to avoid destruction of DUT(device under test). A feedfor- ward-PD controllers are presented by the terms of the position accuracy, the settling time and the force accuracy.y.

  • PDF

Fine Structure of Compound Eye Surface of 2 Species belong to 2 Genera in Korean Laphriinae(Asilidae, Diptera, Insecta) (한국산(韓國産) 벌파리매아과(亞科)(파리매과(科),파리목(目),곤충강(綱)) 2속(屬) 2종(種)의 복안(複眼)표면 미세구조)

  • Lee, Ok-Jin
    • Journal of Korean Ophthalmic Optics Society
    • /
    • v.4 no.2
    • /
    • pp.113-118
    • /
    • 1999
  • The fine structure on the compound eye surface of 2 species(Choerades isshikii (Matsumura), Laphria rufa R$\ddot{o}$der) belong to 2 genera of Laphriinae in Korea was morphologically studied with a scanning electron microscope and image analyser. The compound eye was divided into 3 parts(medial, middle, and lateral) according to a difference in the diameter of a facet. The fine structure of a facet in the medial and middle part was characteristic in Korean Laphriinae. And this morphological character was valuable in taxonomy because of the fine structure was differ from each genus.

  • PDF