• Title/Summary/Keyword: $K_s$

Search Result 199,071, Processing Time 0.119 seconds

(Photosensitive Polymers VII) Mechanism of Photosensitized Curing Reaction of Cinnamoylated Polymers ((感光性 高分子에 關한 硏究 VII) Cinnamoylated Polymers의 光增感 硬化反應機構)

  • Kim, Kwang-Sup;Shim, Jyong-Sup
    • Journal of the Korean Chemical Society
    • /
    • v.10 no.4
    • /
    • pp.166-174
    • /
    • 1966
  • The multistep mechanism of photosensitized curing reaction cinnamoylated photosensitive polymer is proposed from the energy level diagram of cinnamic acid and sensitizer, and from the fact that excess of sensitizer brings the sensitivity to a limiting value etc. Various factors which have effects on the ability of sensitizer are also discussed. The mechanism involves following steps: activation to the first excited singlet states of cinnamoyl group(C) and sensitizer(S) by their absorption of photon, their intersystem crossing to the lowest triplet state, bimolecular internal quenching by formation of excimer of sensitizer, triplet excitation energy transfer and intermolecular addition between cinnamoyl group in ground state and that in triplet state. The rate equation derived from this mechanism is $-\frac{d[C]}{dt} = \frac{K_1[C]}{K_2 + [C]}[\frac{I^c_{abs}}{K_3 + [S]} + \frac{K_4[C]}{(K_5 + [C])(K_6 + [S])}(I^s_{abs} + \frac{K_7I^c_{abs}[S]}{K_8 + [S]})]$ where $I^c_{abs}\;and\;I^s_{abs}$: the rates of absorption of photon by cinnamoyl group and sensitizer $K_n$: Constants. It is proved with the cinnamate of poly(glyceryl phthalate)(PGC) in the absence of sensitizer using the infrared analytical method and successfully applied for the experimental data reported on the effects of the degree of cinnamoyl esterification and the concentration of sensitizer upon the sensitivity.

  • PDF

PROPERTIES OF kth-ORDER (SLANT TOEPLITZ + SLANT HANKEL) OPERATORS ON H2(𝕋)

  • Gupta, Anuradha;Gupta, Bhawna
    • Communications of the Korean Mathematical Society
    • /
    • v.35 no.3
    • /
    • pp.855-866
    • /
    • 2020
  • For two essentially bounded Lebesgue measurable functions 𝜙 and ξ on unit circle 𝕋, we attempt to study properties of operators $S^k_{\mathcal{M}({\phi},{\xi})=S^k_{T_{\phi}}+S^k_{H_{\xi}}$ on H2(𝕋) (k ≥ 2), where $S^k_{T_{\phi}}$ is a kth-order slant Toeplitz operator with symbol 𝜙 and $S^k_{H_{\xi}}$ is a kth-order slant Hankel operator with symbol ξ. The spectral properties of operators Sk𝓜(𝜙,𝜙) (or simply Sk𝓜(𝜙)) are investigated on H2(𝕋). More precisely, it is proved that for k = 2, the Coburn's type theorem holds for Sk𝓜(𝜙). The conditions under which operators Sk𝓜(𝜙) commute are also explored.

ON INTEGRAL DOMAINS IN WHICH EVERY ASCENDING CHAIN ON PRINCIPAL IDEALS IS S-STATIONARY

  • Hamed, Ahmed;Kim, Hwankoo
    • Bulletin of the Korean Mathematical Society
    • /
    • v.57 no.5
    • /
    • pp.1215-1229
    • /
    • 2020
  • Let D be an integral domain and S a multiplicative subset of D. An ascending chain (Ik)k∈ℕ of ideals of D is said to be S-stationary if there exist a positive integer n and an s ∈ S such that for each k ≥ n, sIk ⊆ In. As a generalization of domains satisfying ACCP (resp., ACC on ∗-ideals) we define D to satisfy S-ACCP (resp., S-ACC on ∗-ideals) if every ascending chain of principal ideals (resp., ∗-ideals) of D is S-stationary. One of main results of this paper is the Hilbert basis theorem for an integral domain satisfying S-ACCP. Also we investigate the class of such domains D and we generalize some known related results in the literature. Finally some illustrative examples regarding the introduced concepts are given.

A More Effective Method of IUI

  • Lee, J.Y.;Hwang, K.J.;Chang, H.S.;Choi, H.J.;Kim, Y.B.;Cho, P.J.;Kim, M.R.
    • 대한생식의학회:학술대회논문집
    • /
    • 2001.06a
    • /
    • pp.80.1-80.1
    • /
    • 2001
  • PDF

Design of a MMIC Distributed Amplifier for DC to 25 ㎓ (DC~25 GHz MMIC Distributed Amplifier의 설계)

  • Bae, H.C.;Hong, J.Y.;Park, D.S.;Kim, S.C.;An, D.;Chae, Y.S.;Rhee, J.K.;Youn, Y.S.;Kim, Y.H.
    • Proceedings of the IEEK Conference
    • /
    • 1999.06a
    • /
    • pp.265-268
    • /
    • 1999
  • In this paper, a wideband MMIC distributed amplifier was designed using the fabricated PHEMT with the unit gate width of 80 ${\mu}{\textrm}{m}$ and 4 gate fingers at our Lab. S$_{21}$ gains are 7.1 ~ 10.0 ㏈. Input and output reflection coefficients obtained from the distributed amplifier in the frequency range of DC~25 ㎓ are lower then -8 ㏈. A chip size of the designed wideband MMIC distributed amplifier is 1.9 mm $\times$ 1.1 mm.

  • PDF