• 제목/요약/키워드: local distance

검색결과 1,122건 처리시간 0.028초

메소-스케일 연소 현상의 공학적 의미와 이해 (Understanding and Engineering Meaning of Meso-Scale Combustion Phenomena)

  • 김남일
    • 한국연소학회:학술대회논문집
    • /
    • 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
    • /
    • pp.287-289
    • /
    • 2015
  • Meso-scale combustion is defined as combustion phenomena within limited characteristic length scales that are comparable with the laminar flame length scales. In the laminar flame theory, four representative length scales have been involved; i.e., a reaction layer thickness, a thermal layer thickness, a quenching distance, and a Markstein length. When the effects of these length scales on the flame characteristics are understood, the laminar flame theories can be clarified. Therefore, a study on the meso-scale combustion phenomena should not be thought as just a specific phenomena occurring in an exceptional combustion condition. Instead, all combustion phenomena within meso-scale spaces need to be explained by our knowledge. During this challenge, our understanding on laminar flame structures can be extended. Considering that most turbulent combustion phenomena in engineering application are still have local laminar flame structures, studies on laminar flame structures need to be re-visited especially in academic aspects.

  • PDF

PLANK PROBLEMS, POLARIZATION AND CHEBYSHEV CONSTANTS

  • Revesz, Szilard-Gy.;Sarantopoulos, Yannis
    • 대한수학회지
    • /
    • 제41권1호
    • /
    • pp.157-174
    • /
    • 2004
  • In this work we discuss "plank problems" for complex Banach spaces and in particular for the classical $L^{p}(\mu)$ spaces. In the case $1\;{\leq}\;p\;{\leq}\;2$ we obtain optimal results and for finite dimensional complex Banach spaces, in a special case, we have improved an early result by K. Ball [3]. By using these results, in some cases we are able to find best possible lower bounds for the norms of homogeneous polynomials which are products of linear forms. In particular, we give an estimate in the case of a real Hilbert space which seems to be a difficult problem. We have also obtained some results on the so-called n-th (linear) polarization constant of a Banach space which is an isometric property of the space. Finally, known polynomial inequalities have been derived as simple consequences of various results related to plank problems.

Design of a Wheeled Blimp

  • Sungchul Kang;Mihee Nam;Park, Changwoo;Kim, Munsang
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 제어로봇시스템학회 2001년도 ICCAS
    • /
    • pp.30.5-30
    • /
    • 2001
  • This paper describes a new design of blimp having wheeled vehicle part. This system can work both on the ground using wheeled vehicle and in the air using the floating capability of the blimp part. The passive wheeled mechanism in the vehicle part enables the stable taking off, landing on as well as it is greatly helpful to keep a stationary position on the floor. On the other hand, the floating capability enables the wheeled blimp to fly freely regardless of the ground condition or obstacles. The wheeled blimp can be used as an agent robot for the tole-presence application. Using multimedia devices such as camera, speaker, LCD and microphone mounted on the blimp surface, this system can get necessary information at the local site and communicate with person from a distance. As a typical tele-presence application, the wheeled blimp is currently being developed to a tole-guidance robot working in public indoor areas such 35 exhibition halls, departments, hospitals, etc ...

  • PDF

Improved Free-air Gravity Anomalies by Satellite Altimetry

  • Kim, Jeong-Woo;Roman, Daniel-R.
    • 대한원격탐사학회지
    • /
    • 제17권4호
    • /
    • pp.297-305
    • /
    • 2001
  • Ocean satellite altimetry-implied free-air gravity anomalies have had the shortest wavelengths removed during the processing to generate the optimal solution between multiple radar altimeter missions. ERS-1 168day mission altimetry was residualized to a reference geoid surface generated by integrating Anderson & Knudsen’s free-air gravity anomalies for the Barents Sea. The altimetry tracks were reduced and filtered to extract the shortest wavelengths (between 4 and 111 km) from both ascending and descending tracks, respectively. These data were recombined using existing quadrant-swapping techniques in the wavenumber domain to generate a correlated, high frequency gravity field related to the local geologic sources. This added-value surface adjusted the reference free-air gravity anomalies to better reflect features in the gravity field at a wavelength related to the distance between altimetry ground tracks.

Rapid Identification of Petroleum Products by Near-Infrared Spectroscopy

  • 정호일;최혁진;구민식
    • Bulletin of the Korean Chemical Society
    • /
    • 제20권9호
    • /
    • pp.1021-1025
    • /
    • 1999
  • Near-infrared (NIR) spectroscopy has been successfully utilized for the rapid identification of six typical petroleum products such as light straight-run (LSR), naphtha, kerosine, light gas oil (LGO), gasoline, and diesel. The spectral features of each product were reasonably differentiated in the NIR region, and the spectral differences provided enough qualitative spectral information for discrimination. For discrimination, principal component analysis (PCA) combined with Mahalanobis distance was used to identify each petroleum product from NIR spectra. The results showed that each product was accurately identified with an accuracy over 95%. Most noticeably, LSR, kerosine, gasoline, and diesel samples were predicted with identification accuracy of 99%. The overall results ensure that a portable NIR instrument combined with a multivariate qualitative discrimination method can be efficiently utilized for rapid and simple identification of petroleum products. This is especially important when local at-site measurements are necessary, such as accidental petroleum leakage and regulation of illegal product blending.

HYBRIDIZATION EFFECTS IN $RT_2$ COMPOUNDS (R = Ce, Pr, Nd, Sm, Gd; T = Fe, Co, Ni)

  • Kang, Kicheon;Min, B.I.;Kang, J.S.
    • 한국자기학회지
    • /
    • 제5권5호
    • /
    • pp.376-379
    • /
    • 1995
  • Employing the muffin-tin-orbital theory combined with pseudo-potential concepts, we have evaluated hybridization matrix elements between R and T sites in $RT_{2}$ compounds. The matrix elements are calculated with two parameters, the interatomic distance between R and T atoms from the crystal structure data, and the expectation values of the radial distances for the radial wave functions of the ground state charge densities, which are obtained from the linearized muffin-tin orbital band method within the local density approximation. It is found that the R 4f/T 3d hybridization matrix elements decrease with an increasing atomic number from R=Ce to Gd, and that they are smaller in $RNi_{2}$ than in $RCo_{2}$, which are consistent with trends observed in recent photoemission spectroscopy experiments. It is also found that the magnitudes of the hybridization matrix elements in $RFe_{2}$ are comparable to those in $RNi_{2}$.

  • PDF

Anomalous Nernst Effects of [CoSiB/Pt] Multilayer Films

  • Kelekci, O.;Lee, H.N.;Kim, T.W.;Noh, H.
    • Journal of Magnetics
    • /
    • 제18권3호
    • /
    • pp.225-229
    • /
    • 2013
  • We report a measurement for the anomalous Nernst effects induced by a temperature gradient in [CoSiB/Pt] multilayer films with perpendicular magnetic anisotropy. The Nernst voltage shows a characteristic hysteresis which reflects the magnetization of the film as in the case of the anomalous Hall effects. With a local heating geometry, we also measure the dependence of the anomalous Nernst voltage on the distance d from the heating element. It is roughly proportional to $1/d^{1.3}$, which can be conjectured from the expected temperature gradient along the sample from the heat equation.

GIPOF의 최적 굴절률 분포와 최대 전송거리에 대한 연구 (Theoretical analysis of optimum refractive index profile and maximum transmission length of a GIPOF)

  • Jeong Hun;Kim Seung Taek;Gang Seong Bok;Lee Gyeong Gyun;Gang Hui Seok;Jo Yeong Jun
    • 한국광학회:학술대회논문집
    • /
    • 한국광학회 2003년도 하계학술발표회
    • /
    • pp.14-15
    • /
    • 2003
  • Polymer optical fibers (POFs) are being considered as important high-speed communication media in the area of local area networks, datalinks and optical sensors. Large core diameter (500~1000 $\mu$m) and large numerical aperture (0.2~0.9) in a POF allow easy processing and connectorization, low cost high efficiency of beam coupling from LDs or LEDs, and complete immunity to EMI/EMR. There are many reports about 2.5 Gbps transmission the polymethylmethacrylate (PMMA) graded index (GI) POF over a distance of 100 m. (omitted)

  • PDF

태백 산지 북부의 하천 하각률 분포 (Distribution of Stream Incision Rates in the Northern Part of the Taebaek Mountains)

  • 이광률
    • 한국지형학회지
    • /
    • 제25권4호
    • /
    • pp.1-19
    • /
    • 2018
  • This study tries to identify distributional characteristics of stream incision rates at 23 points in the northern part of the Taebaek Mountains. Soyang-gang, Naerin-cheon, Odae-cheon, Dong-gang and upper reaches of Okdong-cheon Rivers closed to the Range show higher incision rates and the rates clearly decrease with distance from the Range. Therefore, the incision process in the northern part of the Range has been greatly influenced by uplift around the Range, and the Sobaek Mountain Range seem to play a role in the incision process. Limestone areas show lower incision rates due to degradation of terrace surface by dissolution. This study suggests that local hydrological, geological and geomorphological conditions can be regarded as an important factor in stream incision rates, although stream incision rates are greatly influenced by regional uplift.

지역소매 유통회사의 효율 최적화를 위한 Genetic Algorithm의 적용 (Optimization of Local Retail Distribution Company Problem using Genetic Algorithm)

  • 윤항묵;김동우;류광렬
    • 한국항만학회지
    • /
    • 제11권1호
    • /
    • pp.75-83
    • /
    • 1997
  • In this paper, we codify the objective function that should be optimized by using Genetic Algorithm instead of Heuristic method to solve these problems. So, each bit that constitutes one structure can signify each commodity. Therefore, we can exchange customers without restriction if the traveling distance diminishes among the districts. Furthermore, even though the capacity of a customer's commodities exceeds that of a vehicle, the following vehicle can be allocated. Also, we obtained good result by testing with real data. To be brief, we can effectively allocate innumerable commodities, that have various magnitudes and weight, into restricted capacity of the vehicle by applying genetic algorithm that is useful in solving the problems of optimization.

  • PDF