• Title, Summary, Keyword: R*C constant

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Research on R-C Distributed Circuits (R-C 분포회로에 관한 연구)

  • 박송배
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.3 no.2
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    • pp.10-17
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    • 1966
  • A method by which solutions of the differential equations of any other distributed circuits can be obtained is described when the solution of the differential equation of an R-C distributed amplifier is known. A graphical method of transforming any R-C ditributed circuit into an equivalent circuit which has a constant R(x)$cdot$C(x) was also obtained. The theoretical verification of this method is possible. For simplicity, any R-C distributed circuit can be transformed into an equivalent circuit which is a distributed circuit of either constant R(x) or C(x). Using this equivalent circuit and considering a lumped circuit, an approximate analysis and synthesis can be made simply.

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A Study on $90^{\cire}$ Constant Phase Shifter (전송선형 $90^{\cire}$ 정위상기에 관한 연구)

  • 이충웅
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.13 no.6
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    • pp.12-15
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    • 1976
  • This paper presents the realization method of 90$^{\circ}$ constant phase shifter in the VHF band, constructed by the entirely differens idea from the conventional method of the realization of constant phase shifter in the audio frequency range. The construction of 90$^{\circ}$ constant phase shifter is. simple and can be easily realized by using the distributed constant element, transmission line, and the lumped constant elements, R,C,L.

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HARDY-LITTLEWOOD MAXIMAL FUNCTIONS IN ORLICZ SPACES

  • Yoo, Yoon-Jae
    • Bulletin of the Korean Mathematical Society
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    • v.36 no.2
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    • pp.225-231
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    • 1999
  • Let Mf(x) be the Hardy-Littlewood maximal function on $\mathbb{R}^n$. Let $\Phi$ and $\Psi$ be functions satisfying $\Phi$(t) = ${\int^t}_0$a(s)ds and $\Psi(t)$ = ${\int^t}_0$b(s)ds, where a(s) and b(s) are positive continuous such that ${\int^\infty}_0\frac{a(s)}{s}ds$ = $\infty$ and b(s) is quasi-increasing. We show that if there exists a constant $c_1$ so that ${\int^s}_0\frac{a(t)}{t}dt\;c_1b(c_1s)$ for all $s\geq0$, then there exists a constant $c_1$ such that(0.1) $\int_{\mathbb{R^{n}}$ $\Phi(Mf(x))dx\;\leq\;c_2$ $\int_\mathbb{R^{n}}$$\Psi(c_2\midf(x)\mid)dx$ for all $f\epsilonL^1(R^n_$. Conversely, if there exists a constant $c_2$ satisfying the condition (0.1), then there exists a constant $c_1$ so that ${\int^s}_\delta\frac{a(t)}{t}dt=;\leq\;c_1b(c_1s$ for all $\delta$ > 0 and $s\geq\delta$.

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The Electrical Properties of Mutilayer Chip Capacitor with X7R by Addition of Rare-Earth Ions (Y2O3, Er2O3) using Design of Experiments (실험계획법을 적용한 X7R 적층 칩 커패시터의 희토류(Y2O3, Er2O3) 첨가에 따른 전기적 특성)

  • Yoon, Jung-Rag;Moon, Hwan;Lee, Heun-Young
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.3
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    • pp.216-221
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    • 2010
  • Employing statistical design of experiments, the difference in doping behaviors of rare-earth ions and their effects on the dielectric property and microstructure of $BaTiO_3$-MgO-$MnO_2$-($Ba_{0.4}Ca_{0.6}$) $SiO_3-Re_2O_3$ (Re = $Y_2O_3$, $Er_2O_3$) system were investigated. Through the statistical analysis we have found that the amount of $Re_2O_3$ are significantly affecting on the dielectric properties. The $Re_2O_3$ improved the dielectric constant, dielectric loss and R*C constant, so the appropriate contents of $Y_2O_3$ and $Er_2O_3$ were 0.8 ~ 1.2 mol% and 0.8 ~ 1.3 mol%, respectively. The MLCC(mutilayer chip capacitor) with $2.0{\times}1.2{\times}1.2mm$ size and 475 nF was also suited for X7R with the above composition. It showed that the dielectric constant and RC constant were 2,839 and 3,675 ${\Omega}F$, respectively in the sintering condition at $1250^{\circ}C$ in $Po_2$ $10^{-7}$ Mpa.

Analysis on Relations between Travel time and Watershed Characteristics (유역특성(流域特性)과 홍수도달시간(洪水到達時間)과의 상관해석(相關解析))

  • Suh, Seung Duk;Lim, Kyu Dong
    • Current Research on Agriculture and Life Sciences
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    • v.5
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    • pp.158-167
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    • 1987
  • The purpose of this study is to inquire and analyse the relation between traveltime (Tc) and watetshed physical characteristics surveyed such as river length (L), Lea, river main slope (s), base length of time area diagram, and storage constant (k). The results obtained in this study are as follows. The average widths of watersheds were with the range from 4.6 kilometers to 16.7 kilometers. The shape factors of main stream ranged from 0.08 to 0.37. The average slopes to main 8tream were within the range of 1.7-5.5 meter per kilometer. The relation between the base length and traveltime from S. C. S. method, Rational method, and RZIHA+KRAVEN method were derived $Tc=0.524{\times}1.35^c$ (r=0.98), $Tc=0.628{\times}1.339^c$, (r=0.98), $Tc=0.667{\times}1.342^c$ (r=0.97). The base length of the time-area diagram (c) for the IUH was derived as $c=0.9(\frac{L.L_{ca}}{\sqrt{s}})^{0.35}$ and correlation coefficient was 0.98 which defined a high significance. The storage constant K, derived in this study was $K=8.32+0.0213{\frac{L}{\sqrt{s}}}$ with correlation coefficient (0.96). The relation between storage Constant and conventional formula were figured out $Tc=0.0003{\times}3.323^k$ (r=0.97). $Tc=0.00045{\times}3.268^k$ (r=0.99) and $Tc=0.0004{\times}3.26^k$ (r=0.963). The base length (c) and storage constant (k) of time-Area Diagram were very important parts that determined traveltime for flood events. In the estimate of travel time for predicting flood volume, the formula of $Tc=0.524{\times}1.35^c$ that would be available to apply the Nak - Dong river watershed area and homogeneous watershed characteristics was found.

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FINITE TYPE CURVE IN 3-DIMENSIONAL SASAKIAN MANIFOLD

  • Camci, Cetin;Hacisalihoglu, H. Hilmi
    • Bulletin of the Korean Mathematical Society
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    • v.47 no.6
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    • pp.1163-1170
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    • 2010
  • We study finite type curve in $R^3$(-3) which lies in a cylinder $N^2$(c). Baikousis and Blair proved that a Legendre curve in $R^3$(-3) of constant curvature lies in cylinder $N^2$(c) and is a 1-type curve, conversely, a 1-type Legendre curve is of constant curvature. In this paper, we will prove that a 1-type curve lying in a cylinder $N^2$(c) has a constant curvature. Furthermore we will prove that a curve in $R^3$(-3) which lies in a cylinder $N^2$(c) is finite type if and only if the curve is 1-type.

The Study on the Phenomenon of Heat Transfer on a Downward Isothermal Circular Surface by an Impinging of Upward Circular Nozzle Jet (상향 원형노즐 제트에 의한 하향 등온 원형평면에서의 열전달 현상에 관한 연구)

  • Lee, In Jae;Eom, Yong Kyoon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.28 no.11
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    • pp.450-457
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    • 2016
  • While many studies on the heat transfer effect of an impinging jet have been published, most studies focus on the downward impinging jet. This study investigates the impinging jet heat transfer phenomenon when water at a temperature of $24^{\circ}C$ impinges on the downward isothermal circular plate at 60, 70, and $80^{\circ}C$ and when the upward round jet nozzle is 4, 6, and 8 mm diameter with a flow rate 3.6, 4.6, and 5.6 L/min, respectively, and when the ratio of the nozzle clearance/nozzle diameter (H/D) is 1. The results showed that, as the nozzle diameter decreases, the heat transfer coefficient increases at a constant flow rate. The correlation equation of $Nu_r$, $Pr_r$, and $Re_{jg}$ is obtained in the impinging and constant velocity flow region $(Nu_r/Pr^{0.4}_r)Dr=4.6[Re_{jg}(r/R_c)Dr]^{0.8}$ at all flow rates, in the deceleration and falling flow regions $(Nu_r/Pr^{0.4}_r)Dr=42.7{\mid}Re_{jg}(r/R_c)Dr-345.7{\mid}^{0.3}$ at 3.6 L/min, $(Nu_r/Pr^{0.4}_r)Dr=92.4{\mid}Re_{jg}(r/R_c)Dr-16.8{\mid}^{0.2}$ at 4.6 L/min, and $(Nu_r/Pr^{0.4}_r)Dr=322.4{\mid}Re_{jg}(r/R_c)Dr-536.2{\mid}^{0.01}$ at 5.6 L/min.

Piezoelectric and Dielectric Properties of NaNbO3-LiNbO3 Ceramics according to the BaTiO3 Substitution (BaTiO3 치환에 따른 NaNbO3-LiNbO3 세라믹스의 압전 및 유전특성)

  • Lee, Sang-Ho;Yoo, Ju-Hyun;Mah, Suk-Burm;Kim, Seang-Goo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.3
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    • pp.205-209
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    • 2009
  • In this study, in order to develop the composition ceramics for lead-free ultrasonic motor, (1-x-0.09)$NaNbO_{3-x}BaTiO_3-0,09LiNbO_3$ ceramics were fabricated using a conventional mixed oxide process and their piezoelectric and dielectric characteristics were investigated according to the $BaTiO_3$ substitution. All the specimens showed orthorhombic phase structure without secondary phase, $BaTiO_3$ substitution enhanced density, dielectric constant(${\epsilon}_r$) and electromechanical coupling factor($k_p$), However, mechanical quality factor was deteriorated. Curie temperature of specimens was observed as about $380^{\circ}C$. At the $BaTiO_3$ substitution of 4 mol%, density, electromechanical coupling factor($k_p$), dielectric constant(${\epsilon}_r$) and piezoelectric constant($d_{33}$) of specimen showed the optimum value of $4.493g/cm^3$, 0.236, 175, 70 pC/N, respectively.

CHARACTERIZATIONS OF REAL HYPERSURFACES OF TYPE A IN A COMPLEX SPACE FORM USED BY THE ζ-PARALLEL STRUCTURE JACOBI OPERATOR

  • Kim, Nam-Gil;Ki, U-Hang;Kurihara, Hiroyuki
    • Honam Mathematical Journal
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    • v.30 no.3
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    • pp.535-550
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    • 2008
  • Let M be a real hypersurface of a complex space form with almost contact metric structure $({\phi},{\xi},{\eta},g)$. In this paper, we study real hypersurfaces in a complex space form whose structure Jacobi operator $R_{\xi}=R({\cdot},{\xi}){\xi}$ is ${\xi}$-parallel. In particular, we prove that the condition ${\nabla}_{\xi}R_{\xi}=0$ characterize the homogeneous real hypersurfaces of type A in a complex: projective space $P_n{\mathbb{C}}$ or a complex hyperbolic space $H_n{\mathbb{C}}$ when $g({\nabla}_{\xi}{\xi},{\nabla}_{\xi}{\xi})$ is constant and not equal to -c/24 on M, where c is a constant holomorphic sectional curvature of a complex space form.

Microwave dielectric properties of the 0.15(B $a_0.95$S $r_ 0.05$)O-0.15S $m_2$ $O_3$-0.7TiO $_2$ ceramics (0.15(B $a_0.95$S $r_ 0.05$)O-0.15S $m_2$ $O_3$-0.7TiO $_2$ 세라믹스의 마이크로파 유전특성)

  • 박인길;정장호;배선기;이영희
    • Electrical & Electronic Materials
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    • v.8 no.2
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    • pp.224-228
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    • 1995
  • 0.15(B $a_{0.95}$ S $r_{0.05}$)O-0.15S $m_{2}$ $O_{3}$-0.7Ti $O_{2}$ ceramics were fabricated by the mixed-oxide method. Microwave dielectric properties were investigated with sintering conditions. Increasing the sintering temperature from 1300 to 1375[.deg. C], the sintered density was increased from 5.44 to 5.63[g/c $m^{3$]. Increasing the sintering temperature, dielectric constant and quality factor were increased and temperature coefficient of resonant frequency was independent of sintering temperature. In the specimen sintered at 1375[.deg. C], dielectric constant, quality factor and temperature coefficient of resonant frequency were 80.79, 2784(at 3[GHz]), +11.07[ppm/.deg. C], respectively..

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