• Kyungpook Mathematical Journal
• /
• v.60 no.3
• /
• pp.467-475
• /
• 2020

Let G be a chemical graph with vertex set {v₁, v₁, …, v_n} and degree sequence d(G) = (deg_G(v₁), deg_G(v₂), …, deg_G(v_n)). The inverse degree, R(G) of G is defined as $R(G)={\sum{_{i=1}^{n}}}\;{\frac{1}{deg_G(v_i)}}$. The cyclomatic number of G is defined as γ = m - n + k, where m, n and k are the number of edges, vertices and components of G, respectively. In this paper, some upper bounds on the diameter of a chemical graph in terms of its inverse degree are given. We also obtain an ordering of connected chemical graphs with respect to the inverse degree.

• Proceedings of the Korean Magnestics Society Conference
• /
• 2007.05a
• /
• pp.142.2-142.2
• /
• 2007

• Bulletin of the Korean Mathematical Society
• /
• v.50 no.2
• /
• pp.649-657
• /
• 2013

Let R be a commutative Noetherian ring, I an ideal of R and T be a non-zero I-cofinite R-module with dim(T) ${\leq}$ 1. In this paper, for any finitely generated R-module N with support in V(I), we show that the R-modules $Ext^i_R$(T,N) are finitely generated for all integers $i{\geq}0$. This immediately implies that if I has dimension one (i.e., dim R/I = 1), then $Ext^i_R$($H^j_I$(M), N) is finitely generated for all integers $i$, $j{\geq}0$, and all finitely generated R-modules M and N, with Supp(N) ${\subseteq}$ V(I).

• Journal of the Korean Mathematical Society
• /
• v.41 no.5
• /
• pp.773-793
• /
• 2004

We consider a system of particles with locations { $X_{i}$ $^{n}$ (t):t$\geq$0,i＝1,…,n} in $R^{d}$ , time-varying weights { $A_{i}$ $^{n}$ (t) : t $\geq$0,i ＝ 1,…,n} and weighted empirical measure processes $V^{n}$ (t)＝1/n$\Sigma$$_{i=1}$$^{n}$ $A_{i}$ $^{n}$ (t)$\delta$ $X_{i}$ $^{n}$ (t), where $\delta$$_{x}$ is the Dirac measure. It is known that there exists the limit of { $V_{n}$ } in the week* topology on M( $R^{d}$ ) under suitable conditions. If { $X_{i}$ $^{n}$ , $A_{i}$ $^{n}$ , $V^{n}$ } satisfies some diffusion equations, applying Ito formula, we prove a central limit type theorem for the empirical process { $V^{n}$ }, i.e., we consider the convergence of the processes η$_{t}$ $^{n}$ ≡ n( $V^{n}$ -V). Besides, we study a characterization of its limit.t.

• The Korean Journal of Physiology and Pharmacology
• /
• v.4 no.1
• /
• pp.33-40
• /
• 2000

This study was designed to clarify the mechanism of the inhibitory action of a nitric oxide (NO) donor, 3-morpholino-sydnonimine (SIN-1), on contraction, cytosolic $Ca^{2+}$ level $([Ca^{2+}]_i)$ and ionic currents in guinea-pig ileum. SIN-1 $(0.01{\sim}100\;{\mu}M)$ inhibited 25 mM KCl- or histamine $(10\;{\mu}M)-induced$ contraction in a concentration-dependent manner. SIN-1 reduced both the 25 mM KCl- and the histamine-stimulated increases in muscle tension in parallel with decreased $[Ca^{2+}]_i.$ Using the patch clamp technique with a holding potential of -60 mV, SIN-1 $(10\;{\mu}M)$ decreased peak Ba currents $(I_{Ba})$ by $30.9{\pm}5.4%$ (n=6) when voltage was stepped from -60 mV to +10 mV and this effect was blocked by ODQ $(1\;{\mu}M),$ a soluble guanylyl cyclase inhibitor. Cu/Zn SOD (100 U/ml), the free radical scavenger, had little effect on basal $I_{Ba},$ and SIN-1 $(10\;{\mu}M)$ inhibited peak $I_{Ba}$ by $32.4{\pm}5.8%$ (n=5) in the presence of Cu/Zn SOD. In a cell clamped at a holding-potential of -40 mV, application of $10\;{\mu}M$ histamine induced an inward current. The histamine-induced inward current was markedly and reversibly inhibited by $10\;{\mu}M$ SIN-1, and this effect was abolished by ODQ $(1\;{\mu}M).$ In addition, SIN-1 markedly increased the depolarization-activated outward $K^+$ currents in the all potential ranges. We concluded that SIN-1 inhibits smooth muscle contraction mainly by decreasing $[Ca^{2+}]_i$ resulted from the inhibition of L-type $Ca^{2+}$ channels and the inhibition of nonselective cation currents and/or by the activation of $K^+$ currents via a cGMP-dependent pathway.

• Microbiology and Biotechnology Letters
• /
• v.24 no.3
• /
• pp.380-383
• /
• 1996

Adenosine deaminase inhibitor was extracted from culture broth of Streptomyces sp. strain V-8 with ethylacetate. The ethylacetate extract showed the characteristic UV absorption spectrum of actinomycins at 440-450 nm. The ethylacetate extract was compared with respect to inhibitory behavior against adenosine deaminase from calf intestinal mucosa with actinomycin D, -C complex and actinomycin V. The Ki values for actnomycin D, -C complex, and actinomycin V against adenosine deaminase were determined to be 9.9 $\times$ 10$^{-6}$ M, 9.6 $\times$ 10$^{-6}$ M and 9.3 $\times$ 10$^{-6}$ M, respectively. The Ki value for the ethylacetate extract of culture broth against adenosine deaminase was determined to be 5.7 $\times$ 10$^{-6}$ M. The kinetic parameters of actinomycin D, -C complex, -V and ethylacetate extract of culture broth for adenosine deaminase were as follows:I$_{50}$ = 1.5 $\times$ 10$^{-5}$ M (actinomycin D), 2.7 $\times$ 10$^{-5}$ M (actinomycin C complex), 3.5 $\times$ 10$^{-5}$ M (actinomycin V), 8.9 $\times$ 10$^{-6}$ M (ethylacetate extract of culture broth). The adenosine deaminase was inhibited noncompetitively by ethylacetate extract of culture broth as well as by actinomycin D, -C complex and actinomycin V.

• Bulletin of the Korean Mathematical Society
• /
• v.61 no.1
• /
• pp.273-280
• /
• 2024

Let I be an ideal of a commutative Noetherian semi-local ring R and M be an R-module. It is shown that if dim M ≤ 2 and Supp_R M ⊆ V (I), then M is I-weakly cofinite if (and only if) the R-modules Hom_R(R/I, M) and Ext¹_R(R/I, M) are weakly Laskerian. As a consequence of this result, it is shown that the category of all I-weakly cofinite modules X with dim X ≤ 2, forms an Abelian subcategory of the category of all R-modules. Finally, it is shown that if dim R/I ≤ 2, then for each pair of finitely generated R-modules M and N and each pair of the integers i, j ≥ 0, the R-modules Tor^R_i(N, H^j_I(M)) and Extⁱ_R(N, H^j_I(M)) are I-weakly cofinite.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.12 no.6
• /
• pp.890-898
• /
• 2001

4H-SiC(silicon carbide) MESFET large signal model was studied using modified Materka-Kacprzak large signal MESFET model. 4H-SiC MESFET device simulation have been conducted by Silvaco\`s 2D device simulator, ATLAS. The result is modeled using modified Materka large signal model. simulation and modeling results are -8 V pinch off voltage, under V$\_$GS/=0 V, V$\_$DS/=25 V conditions, I$\_$DSS/=270 mA/mm, G$\_$m/=52.8 ms/mm were obtained. Through the power simulation 2 GHz, at the bias of V$\_$GS/-4 V md V$\_$DS/=25 V, 10 dB Gain, 34 dBm (1dB compression point)output porter, 7.6 W/mm power density, 37% PAE(power added efficiency) were obtained.7.6 W/mm power density, 37% PAE(power added efficiency) were obtained.d.

• Phonetics and Speech Sciences
• /
• v.2 no.3
• /
• pp.101-113
• /
• 2010

The present study investigated how the kinematics of the /a/-to-/i/ tongue movement in Korean would be influenced by prosodic boundary. The /a/-to-/i/ sequence was used as 'transboundary' test materials which occurred across a prosodic boundary as in /ilnjəʃ$^h$a/ # / minsakwae/ ('일년차#민사과에' 'the first year worker' # 'dept. of civil affairs'). It also tested whether the V-to-V tongue movement would be further influenced by its syllable structure with /m/ which was placed either in the coda condition (/am#i/) or in the onset condition (/a#mi). Results of an EMA (Electromagnetic Articulagraphy) study showed that kinematical parameters such as the movement distance (displacement), the movement duration, and the movement velocity (speed) all varied as a function of the boundary strength, showing an articulatory strengthening pattern of a "larger, longer and faster" movement. Interestingly, however, the larger, longer and faster pattern associated with boundary marking in Korean has often been observed with stress (prominence) marking in English. It was proposed that language-specific prosodic systems induce different ways in which phonetics and prosody interact: Korean, as a language without lexical stress and pitch accent, has more degree of freedom to express prosodic strengthening, while languages such as English have constraints, so that some strengthening patterns are reserved for lexical stress. The V-to-V tongue movement was also found to be influenced by the intervening consonant /m/'s syllable affiliation, showing a more preboundary lengthening of the tongue movement when /m/ was part of the preboundary syllable (/am#i/). The results, together, show that the fine-grained phonetic details do not simply arise as low-level physical phenomena, but reflect higher-level linguistic structures, such as syllable and prosodic structures. It was also discussed how the boundary-induced kinematic patterns could be accounted for in terms of the task dynamic model and the theory of the prosodic gesture ($\pi$-gesture).

• The Korean Journal of Physiology and Pharmacology
• /
• v.4 no.6
• /
• pp.479-486
• /
• 2000

The aim of this study was to clarify the mechanism of the inhibitory action of carbon monoxide (CO) on contraction, by measuring cytosolic $Ca^{2+}$ level $([Ca^{2+}]_i)$ and ionic currents in guinea-pig ileum. CO (10%) inhibited 40 mM KCl-induced contraction and this effect was blocked by ODQ $(1\;{\mu}M),$ a soluble guanylyl cyclase (sGC) inhibitor. CO inhibited the 40 mM KCl-induced contraction without changing $[Ca^{2+}]_i.$ Cumulative addition of KCl induced a graded increase in $[Ca^{2+}]_i$ and muscle tension. In the presence of CO, cumulative addition of KCl induced smaller contraction than in the absence of CO. On the other hand, the increase in $[Ca^{2+}]_i$ induced by cumulative addition of KCl was only slightly decreased in the presence of CO, and the $[Ca^{2+}]_i-tension$ relationship shifted downwards. Using the patch clamp technique with a holding potential of -60 mV, we found that CO had little effect on the peak Ba currents $(I_{Ba})$ when voltage was stepped from -60 mV to 0 mV. In addition, CO showed no effect on the depolarization-activated outward $K^+$ currents in the all potential ranges. We conclude that CO inhibits smooth muscle contraction mainly by decreasing the $Ca^{2+}$ sensitivity of contractile elements via a cGMP-dependent pathway, not by involving L-type $Ca^{2+}$ and outward-potassium currents in guinea-pig ileum.