• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.6
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• pp.539-546
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• 2016

In this paper, the effect of J-R curve changes on the determination of parameters in a failure model owing to the presence or absence of a side groove in a C(T) specimen is investigated. A stress-modified fracture strain model is implemented for FE damage simulations. C(T) specimens were taken from SA508 grade 1a low-alloy steel piping material, and some of them were processed with a side groove. Fracture toughness tests were performed at room temperature and at $316^{\circ}C$. The parameters of the failure model were determined by damage simulations using the J-R curves obtained from the tests. Finally, the results show that the determination of failure model parameters is not affected by variations in J-R curves owing to the presence or absence of a side groove.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.1
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• pp.51.1-51.1
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• 2013

We present molecular line observations of a small group of Young Stellar Objects (YSOs), L1251C. Observations by Spitzer Space Telescope legacy program "From Molecular Cores to Planet Forming Disks"(c2d; Evans et al. 2003) revealed that there are three YSOs within ~15" in L1251C: IRS1 (Class I), IRS2 (Class II), and IRS3 (Class II). In order to understand the molecular environment around these YSOs, we carried out the KVN single-dish observations in $HCO^+$ J=1-0, $H^{13}CO^+$ J=1-0, $N_2H^+$ J=1-0 and HCN J=1-0. CO J=1-0 was also mapped in L1251C with the TRAO 14m telescope. Integrated intensity maps of high density tracers such as $H^{13}CO^+$ J=1-0, $N_2H^+$ J=1-0 and HCN J=1-0 show similar emission distributions, whose peaks are off from the positions of YSOs. However, $HCO^+$ J=1-0, which is believed to trace both infall and outflow, presents its emission distribution different from those of other molecular transitions. The line profile of $HCO^+$ J=1-0 is superimposed by two velocity (narrow and broad) components. The $HCO^+$ outflow map reveals multiple structures while the CO outflow map elongates mainly along the EW direction. With the KVN single dish, the 22 GHz $H_2O$ maser emission has been also monitored toward L1251C to find variations of the systemic velocity and intensity with time.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.745-746
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• 2009

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2019.08a
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• pp.104-119
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• 2019

• Journal of the Chungcheong Mathematical Society
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• v.23 no.1
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• pp.49-57
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• 2010

It is shown that for a derivation $$f(x_1{\cdots}x_{j-1}x_jx_{j+1}{\cdots}x_k)=\sum_{j=1}^{k}x_{1}{\cdots}x_{j-1}x_{j+1}{\cdots}x_kf(x_j)$$ on a unital $C^*$-algebra $\mathcal{B}$, there exists a unique $\mathbb{C}$-linear *-derivation $D:{\mathcal{B}}{\rightarrow}{\mathcal{B}}$ near the derivation, by using the Hyers-Ulam-Rassias stability of functional equations. The concept of Hyers-Ulam-Rassias stability originated from the Th.M. Rassias' stability theorem that appeared in his paper: On the stability of the linear mapping in Banach spaces, Proc. Amer. Math. Soc. 72 (1978), 297-300.

• East Asian mathematical journal
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• v.24 no.3
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• pp.251-261
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• 2008

Let {${\xi}_j;j\;{\geq}\;1$} be a centered strictly stationary random sequence defined by $S_0\;=\;0$, $S_n\;=\;\Sigma^n_{j=1}\;{\xi}_j$ and $\sigma(n)\;=\;33\sqrt {ES^2_n}$ where $\sigma(t),\;t\;>\;0$, is a nondecreasing continuous regularly varying function. Suppose that there exists $n_0\;{\geq}\;1$ such that, for any $n\;{\geq}\;n_0$ and $0\;{\leq}\;{\varepsilon}\;<\;1$, there exist positive constants $c_1$ and $c_2$ such that $c_1e^{-(1+{\varepsilon})x^2/2}\;{\leq}\;P\{\frac{{\mid}S_n{\mid}}{\sigma(n)}\;{\geq}\;x\}\;{\leq}\;c_2e^{-(1-{\varepsilon})x^2/2$, $x\;{\geq}\;1$ Under some additional conditions, we investigate some limsup results for the increments of partial sum processes of the sequence {${\xi}_j;j\;{\geq}\;1$}.

• Bulletin of the Korean Mathematical Society
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• v.46 no.2
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• pp.311-319
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• 2009

Let H be a Hilbert space which is the direct sum of five closed subspaces $X_0,\;X_1,\;X_2,\;X_3$ and $X_4$ with $X_1,\;X_2,\;X_3$ of finite dimension. Let J be a $C^{1,1}$ functional defined on H with J(0) = 0. We show the existence of at least four nontrivial critical points when the sublevels of J (the torus with three holes and sphere) link and the functional J satisfies sup-inf variational inequality on the linking subspaces, and the functional J satisfies $(P.S.)^*_c$ condition and $f|X_0{\otimes}X_4$ has no critical point with level c. For the proof of main theorem we use the nonsmooth version of the classical deformation lemma and the limit relative category theory.

• 한국초전도학회:학술대회논문집
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• 2009.07a
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• pp.54-54
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• 2009

• Korean Chemical Engineering Research
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• v.55 no.5
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• pp.600-608
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• 2017

Hazard risk of explosion on pharmaceutical raw materials dust in pharmaceutical industry often exists when it is handled or processed in the industrial sites, and explosion accident is caused by this. In this study, the dust explosion characteristics of the three pharmaceutical raw materials samples were measured. The main explosion characteristics are as follows: $P_{max}$, MIE and MIT of loxoprofen acid having $5.31^{\circ}C$ of median diameter are obtained 8.4 bar, 1 mJ < MIE < 3 mJ and $550^{\circ}C$. $P_{max}$, MIE and MIT of camphorsulfonate having $95.63^{\circ}C$ of median diameter are obtained 7.9 bar, 30 mJ < MIE < 100 mJ and $510^{\circ}C$. $P_{max}$, MIE and MIT of rifampicine having $26.48^{\circ}C$ of median diameter are obtained 7.9 bar and 1 mJ < MIE < 3 mJ and $470^{\circ}C$. The deflagration index ($K_{st}$) and the explosion index (EI) were obtained by using these data. The explosion hazard assessment of pharmaceutical raw materials dust was compared and examined. As a result, the explosion hazard assessment according to deflagration index and explosion index were the explosion class with St 2 and the explosion hazard rating of severe for loxoprofen acid & rifampicine and St 1 and strong for clopidogrel camphorsulfonate, respectively.

• Korean Journal of Mathematics
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• v.18 no.4
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• pp.395-407
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• 2010

In this paper, we prove the generalized Hyers-Ulam stability of the following quadratic functional equations $$cf\(\sum_{i=1}^{n}x_i\)+\sum_{j=2}^{n}f\(\sum_{i=1}^{n}x_i-(n+c-1)x_j\)\\=(n+c-1)\(f(x_1)+c\sum_{i=2}^{n}f(x_i)+\sum_{i<j,j=3}^{n}\(\sum_{i=2}^{n-1}f(x_i-x_j\)\),\\Q\(\sum_{i=1}^{n}d_ix_i\)+\sum_{1{\leq}i<j{\leq}n}d_id_jQ(x_i-x_j)=\(\sum_{i=1}^{n}d_i\)\(\sum_{i=1}^{n}d_iQ(x_i)\)$$ in random normed spaces.