• 제목/요약/키워드: Absorption Features

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Room Acoustic Design in International Convention Center Jeju (제주국제컨벤션센터 컨퍼런스홀의 건축음향 설계)

  • 주현경;오양기;두세진;김하근
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.05a
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    • pp.802-807
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    • 2003
  • International Convention Center Jeju(ICCJ) was planed and built for accommodating a variety of conventional and exhibitional activities. For a better flexibility of operation, almost all rooms in ICCJ are designed to be subdivided Into a couple of small rooms with installation of movable partition walls. Architectural and acoustical design should be deliberatively and cooperatively undertaken to cope with such a complex condition. Conference hall, the largest room in ICCJ, has a capacity of 5000 seats who:1 used as a whole. It could be divided into 3 halls, one with 2000 pre-installed seats on slanted floor, up/down removable stage and its settings above, and the other 2 flat rooms with no seats installed. A devided hall with pre-installed seats and stage is designed for a multi-use auditorium. Almost all surfaces except ceilings adjacent to the stage are sound absorptively treated, in regard to extensive use of sound reinforcement systems. Its reverberation time 1.65 sec without audience, which is roughly correspond to 1.50 sec with fully occupied audience. When there is a need for a larger room, all the partition wail Is removed and the hall could be used as a whole. Exhibition hall is located in the first floor of ICCJ. Absorption and softness are needed for the hat 1 because exhibition behavior has something noisy features. Perforated MDF panels with porous materials and air space in the back groundare adopted for the walls. There are one large, two medium, and several small convention rooms in ICJJ. The room are also acoustically designed for maximum flexibility with no defects soundwisely.

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A Thermal Model for Silicon-on-Insulator Multilayer Structure in Silicon Recrystallization Using Tungsten Lamp (텅스텐 램프를 이용한 실리콘 재결정시의 SOI 다층구조에 대한 열적모델)

  • 경종민
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.21 no.5
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    • pp.90-99
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    • 1984
  • A onetimensional distribution of the temperature and the heat source in the SOI (silicon-on-insulator) multi-layer structure illuminated by tungsten lamps from both sides was obtained by solving the heat equation in steady state on a finite difference grid using successive over-relaxation method. The heat source distribution was obtained by considering such features as spectral components of the light source, multiple reflection at the internal interfaces, temperature and frequency dependence of the light absorption coefficient, etc. The front and back surface temperatures, which are boundary conditions for the heat equation, were derived from a requirement that they satisfy the radiation conditions. The radiation flux as well as the conduction flux was considered in modelling the thermal behaviour at the internal interfaces. Since the temperature and the heat source profiles are strongly dependent upon each other, the calculation of each profile was iterated using the updated profile of the other until they are consistent with each other. The experimental temperature at the front surface of the wafer as measured by Pyrometer was about 1200$^{\circ}$K, while the simulated temperature was 1120$^{\circ}$K.

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Crystal growth and optical properties of near-stoichiometric $Zn:LiNbO_3$ fiber single crystal by ${\mu}-PD$ method (${\mu}-PD$ 법으로 성장시킨 near-stoichiometric 조성 $Zn:LiNbO_3$ fiber 단결정 성장 및 광손상 특성)

  • Lee, H.J.;Shur, J.W.;Shin, T.I.;Song, W.Y.;Yoon, D.H.
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.16 no.6
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    • pp.235-239
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    • 2006
  • ZnO-doped near-stoichiometric $LiNbO_3$ single crystals of $0.8{\sim}1.0mm$ diameter and $30{\sim}35mm$ length were grown by the micro-pulling down (U-PD) method. The structure of the grown crystals was confirmed by powder x-ray diffraction (XRD) patterns. Electron probe micro analysis (EPMA) showed that Zn ions were homogeneously incorporated In grown crystals. The threshold in ZnO doping level was confirmed that an abrupt change in the features of $OH^-$ absorption band as doping level reaching about 2 mol%.

Structural and Magnetic Properties of Monomeric and Dimeric Copper(II) Complexes with Phenyl-N-[(pyridine-2-yl)methylene]methaneamide

  • Lee, Hong-Woo;Sengottuvelan, Nallathambi;Seo, Hoe-Joo;Choi, Jae-Soo;Kang, Sung-Kwon;Kim, Young-Inn
    • Bulletin of the Korean Chemical Society
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    • v.29 no.9
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    • pp.1711-1716
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    • 2008
  • The reaction of copper(II) chloride with phenyl-N-[(pyridine-2-yl)methylene]methaneamide (ppmma) leads to a new $\mu$ -chloro bridged dimeric [Cu(ppmma)$Cl_2$]$_2$ complex, whereas a reaction of copper(II) bromide with ppmma affords a monomeric Cu(ppmma)$Br_2$ complex. Both complexes have been characterized by X-ray crystallography and electronic absorption spectroscopy. The crystal structural analysis of [Cu(ppmma)$Cl_2$]$_2$ shows that the two Cu(II) atoms are bridged by two chloride ligands, forming a dimeric copper(II) complex and the copper ion has a distorted square-pyramidal geometry ($\tau$ = 0.2). The dimer units are held through a strong intermolecular $\pi-\pi$ interactions between the nearest benzyl rings. On the other hand, Cu(ppmma)Br2 displayed a distorted square planar geometry with two types of strong intermolecular π-π interaction. EPR spectrum of [Cu(ppmma)$Cl_2$]$_2$ in frozen glas s at 77 K revealed an equilibrium between the mononuclear and binuclear species. The magnetic susceptibilities data of [Cu(ppmma)$Cl_2$]$_2$ and Cu(ppmma)$Br_2$ follow the Curie-Weiss law. No significant intermolecular magnetic interactions were examined in both complexes, and magnetic exchange interactions are discussed on the basis of the structural features.

Identification and spectral analysis of the CIBER/LRS detected stars

  • Kim, MinGyu;Matsumoto, T.;Lee, Hyung Mok;Arai, T.;Battle, J.;Bock, J.;Brown, S.;Cooray, A.;Hristov, V.;Keating, B.;Korngut, P.;Lee, Dae-Hee;Levenson, L.R.;Lykke, K.;Mason, P.;Matsuura, S.;Nam, U.W.;Renbarger, T.;Smith, A.;Sullivan, I.;Wada, T.;Jeong, Woong-Seob;Zemcov, M.
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.2
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    • pp.141.1-141.1
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    • 2012
  • CIBER (Cosmic Infrared Background ExpeRiment) is a sounding-rocket borne experiment which is designed to find the evidence of the First stars (Pop.III stars) in the universe. They are expected to be formed between the recombination era at z ~ 1100 and the most distant quasar (z ~ 8). They have never been directly detected due to its faintness so far, but can be observed as a background radiation at around $1{\mu}m$ which is called the Cosmic Near-Infrared Background (CNB). The CIBER is successfully launched on July 10, 2010 at White Sands Missile Range, New Mexico, USA. It consists of three kinds of instruments. One of them is a LRS (Low Resolution Spectrometer) which is a refractive telescope of 5.5 cm aperture with spectral resolution of 20 ~ 30 and wavelength coverage of 0.7 to $2.0{\mu}m$ to measure the spectrum of the CNB. Since LRS detects not only CNB but also stellar components, we can study their spectral features with the broad band advantage especially at around $1{\mu}m$ which is difficult at ground observations because of the atmospheric absorption by water vapor. I identified around 300 stars from observed six fields. If we can classify their spectral types with SED fitting, we can study their physical conditions of the stellar atmosphere as well as making a stellar catalogue of continuous stellar spectrum.

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2-dimensional Mapping of Sulfur Dioxide and Bromine Oxide at the Sakurajima Volcano with a Ground Based Scanning Imaging Spectrograph System

  • Lee, Han-Lim;Kim, J.-Hoon;Ryu, Jae-Yong;Kwon, Soon-Chul;Noh, Young-Min;Gu, Myo-Jeong
    • Journal of the Optical Society of Korea
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    • v.14 no.3
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    • pp.204-208
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    • 2010
  • A scanning imaging spectrograph system was used in this study to retrieve readings of the 2-D distribution of $SO_2$ and BrO around the crater of the Sakurajima volcano in Japan. The measurement was carried out during the daytime on November 2, 2005. Measurements were made at the surface of the site, located 5 km from the Sakurajima crater. One hundred horizontal scans were performed. Each column scanned by the system consists of 64 vertical pixels in order to retrieve the spatial distributions of BrO and $SO_2$ in the plume in terms of slant column densities (SCDs). Measured spectra were analyzed to identify and quantify $SO_2$ and BrO in the volcanic plume utilizing the plume's specific absorption features in the ultra violet region. Two-dimensional BrO and $SO_2$ distributions in SCD were retrieved horizontally covering the upwind, crater and downwind areas, and vertically, including the plume in the center of the scanned image. Both horizontal and vertical dispersions of $SO_2$ SCD from the crater were successfully measured to be from $10^{17}$ to $4.5{\times}10^{18}$ molecules $cm^{-2}$. However, BrO was measured below $10^{15}$ molecules $cm^{-2}$, which is considered its background level.

Improvement of Land Cover / Land Use Classification by Combination of Optical and Microwave Remote Sensing Data

  • Duong, Nguyen Dinh
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.426-428
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    • 2003
  • Optical and microwave remote sensing data have been widely used in land cover and land use classification. Thanks to the spectral absorption characteristics of ground object in visible and near infrared region, optical data enables to extract different land cover types according to their material composition like water body, vegetation cover or bare land. On the other hand, microwave sensor receives backscatter radiance which contains information on surface roughness, object density and their 3-D structure that are very important complementary information to interpret land use and land cover. Separate use of these data have brought many successful results in practice. However, the accuracy of the land use / land cover established by this methodology still has some problems. One of the way to improve accuracy of the land use / land cover classification is just combination of both optical and microwave data in analysis. In this paper for the research, the author used LANDSAT TM scene 127/45 acquired on October 21, 1992, JERS-1 SAR scene 119/265 acquired on October 27, 1992 and aerial photographs taken on October 21, 1992. The study area has been selected in Hanoi City and surrounding area, Vietnam. This is a flat agricultural area with various land use types as water rice, secondary crops like maize, cassava, vegetables cultivation as cucumber, tomato etc. mixed with human settlement and some manufacture facilities as brick and ceramic factories. The use of only optical or microwave data could result in misclassification among some land use features as settlement and vegetables cultivation using frame stages. By combination of multitemporal JERS-1 SAR and TM data these errors have been eliminated so that accuracy of the final land use / land cover map has been improved. The paper describes a methodology for data combination and presents results achieved by the proposed approach.

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Comparison of Pregnant Women's Mechanical Energy between the Period of Pregnancy and Postpartum (임신 기간 및 출산 후의 임산부 보행의 역학적 에너지 변화)

  • Hah, Chong-Ku;Yi, Jae-Hoon
    • Korean Journal of Applied Biomechanics
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    • v.20 no.4
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    • pp.387-393
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    • 2010
  • The purpose of this study was to compare pregnant women's gait parameters and mechanical energies caused by changes in hormone levels and anatomical features such as body mass, body-mass distribution, joint laxity, and musculo-tendinous strength from pregnancy to postpartum. Ten subjects (height: $161{\pm}6.5cm$, mass: $62.7{\pm}10.4\;kg$, $66.4{\pm}9.3\;kg$, $68.4{\pm}7.7\;kg$, $57.2{\pm}7.7\;kg$) participated in the four times experiments (the first, middle, last term and after birth) and walked ten trials at a self-selected pace without shoes. The gait motions were captured with Qualisys system and gait parameters were calculated with Visual-3D. Pregnant women's gait velocities were decreased during the pregnancy periods, but increased after birth. Stride width and cycle time were increased during pregnancy, but decreased after birth. Thigh energy (77.4%) was greater than shank energy (19.06%) or feet (3.54%) about total energy of the lower limbs. Their feet (Left R2=0.881, Right R2=0.852) and shank (Left R2=0.318, Right R2=0.226) energies were significantly increased (positive correlation), but double limb stance time (DLST, R2=0.679) and body total energy (R2=0.138) were decreased (negative correlation) for their velocities. These differences suggest that thigh segment may be a dominant segment among lower limbs, and have something to do with gait velocities. Further studies should investigate joint power and joint work to find energy dissipation or absorption from pregnancy period to postpartum.

The Effect of Sphingosine-1-Phosphate in Survival of Grafted Fat Tissues (Sphingosine-1-Phosphate (S1P)가 이식지방의 생존에 미치는 영향)

  • Yoon, Dong-Ju;Choi, Soo-Jong;Choi, Chi-Won;Nam, Su-Bong;Bae, Yong-Chan
    • Archives of Plastic Surgery
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    • v.37 no.6
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    • pp.726-731
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    • 2010
  • Purpose: Autologous fat grafting is a popular procedure for the correction of the soft tissue depression and deformity. But there are several issues required to be carefully considered in relation to this procedure, mainly about the unpredictability and the low survival rate of the grafted fat due to absorption and partial necrosis. Sphingosine-1-phosphate (S1P) is a lysophospholipid mediator that has been proposed to promote angiogenesis and to regulate the differentiation of adipose derived stromal cells (ASCs). In this study, we analyzed the viability of the grafted fat tissue mixed with S1P into each 12 nude mice (cann.cg-fox1nu/crlori) compared to the group of mice grafted fat tissue only. Methods: Human aspirated fat was grafted subcutaneously into the backs of 8-week-old nude mice with or without S1P. Eight weeks later, the grafted fat was harvested and the weight and volume were checked. The fat was stained with hematoxylin-eosin and 4',6-diamidino-2-phenylindole. Results: S1P group weighed significantly more than the control group (p=0.009), and the volume from the S1P group was considerably larger than that of the control group (p=0.004) either. In histological features, the surviving layer of the S1P group was thicker than the control group and microvasculature appeared to be prominent in the S1P group, especially in the outer layers. Conclusion: These findings suggest that S1P plays a vital role in the soft tissue augmentation, potentially providing a novel point of the control in adipose tissue for microfat graft.

A Study on the Design and Development of Robot Game-based Project for Teaching Children to Program Computers (프로그램교육 목적의 로봇게임 프로젝트 학습 구안에 관한 연구)

  • Shin, Seung-Young;You, Sang-Mi;Kim, Mi-Ryang
    • Journal of Internet Computing and Services
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    • v.10 no.6
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    • pp.159-171
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    • 2009
  • The objective of this research is to explore a method to utilize a programmable robot, as a potential learning tool in the elementary school's curricula. Due to their programmability and operational ease of use, programmable robots are among digital toys that today offer specially instructive features. In this research, we developed the robot game-based project contents as a tool for teaching the elementary school children to learn the algorithm, the essential part of computer programming. The LEGO material, selected as the construction kit for robot, consists of a mechanical assembly system, a set of sensors and actuators, a central control unit, a programming environment. The project requires the children to complete 3 separate tasks, each of which is developed based on the principles of algorithm. The classroom feedback supports that the robotic experiences provided the children with fun and absorption. It is likely that implementing learning with robot in regular classroom in elementary school can bring new possibilities to the educational system, provided that a thorough preparation backs up the plan.

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