• Bulletin of the Korean Chemical Society
• /
• 제7권5호
• /
• pp.331-334
• /
• 1986

The crystal structure of thiamin tetrahydrofurfuryl disulfide, one of the ring-opened derivatives of thiamin, has been determined by the X-ray diffraction methods. The crystal is monoclinic with cell dimensions of a = 8.704 (1), b = 11.207 (2), c = 21.260 (3) ${\AA}$ and ${\beta}$ = 92.44 (2)$^{circ}$, space group P2$_{1}$/c and Z = 4. The structure was solved by direct methods and refined to R = 0.076 for 1252 observed reflections measured on a diffractometer. The molecule assumes a folded conformation in which the pyrimidine and the tetrahydrofurfuryl rings are on the same side of the ethylenic plane. The pyrimidinyl, N-formyl and ethylenic planes are mutually perpendicular to each other and the N(3)-C(4) bond retains a single bond character. The structure is stabilized by an intramolecular N(4'${\alpha})-H{\cdots}O(2{\alpha}$) hydrogen bond. The molecules are connected via N(4'${\alpha}$)-H{\cdots}(N3')$ and O(5${\gamma})-H{\cdots}(N1')$ hydrogen bonds, forming a two-dimensional hydrogen-bonding network. The tetrahydrofurfuryl ring is dynamically disordered. The overall conformation as well as the packing mode is very similar to that of thiamin propyl disulfide.

• 대한수학회지
• /
• 제54권6호
• /
• pp.1733-1757
• /
• 2017

Let $R={\oplus}_{{\alpha}{\in}{\Gamma}}R_{\alpha}$ be an integral domain graded by an arbitrary torsionless grading monoid ${\Gamma}$, ${\bar{R}}$ be the integral closure of R, H be the set of nonzero homogeneous elements of R, C(f) be the fractional ideal of R generated by the homogeneous components of $f{\in}R_H$, and $N(H)=\{f{\in}R{\mid}C(f)_v=R\}$. Let $R_H$ be a UFD. We say that a nonzero prime ideal Q of R is an upper to zero in R if $Q=fR_H{\cap}R$ for some $f{\in}R$ and that R is a graded UMT-domain if each upper to zero in R is a maximal t-ideal. In this paper, we study several ring-theoretic properties of graded UMT-domains. Among other things, we prove that if R has a unit of nonzero degree, then R is a graded UMT-domain if and only if every prime ideal of $R_{N(H)}$ is extended from a homogeneous ideal of R, if and only if ${\bar{R}}_{H{\backslash}Q}$ is a graded-$Pr{\ddot{u}}fer$ domain for all homogeneous maximal t-ideals Q of R, if and only if ${\bar{R}}_{N(H)}$ is a $Pr{\ddot{u}}fer$ domain, if and only if R is a UMT-domain.

• 천문학회보
• /
• 제36권1호
• /
• pp.82.2-82.2
• /
• 2011

Infra-Red Dark Clouds (IRDCs) seen silhouette against the bright Galactic background in mid-IR are a class of interstellar clouds that are dense and cold with very high column densities. While IRDCs are believed to be the precursors to massive stars and star clusters, individual IRDCs show diverse star forming activities within them. We report a remarkable example of such cloud, the IRDC at ${\Gamma}53.2^{\circ}$, and star formation activity in this cloud. The IRDC was previously identified in part as three separate, arcmin-size clouds in the catalogue of MSX IRDC candidates, but we found that the IRDC is associated with a long, filamentary CO cloud at 2 kpc from the Galactic Ring Survey data of $^{13}CO$ J = 1-0 emission, and that its total extent reaches ~ 30pc. The Spitzer MIPSGAL 24mm data show a number of reddened mid-IR sources distributed along the IRDC which are probably young stellar objects (YSOs), and the UWISH2 $H_2$ data (2.122mm) reveal ubiquitous out flows around them. These observations indicate that the IRDC is a site of active star formation with YSOs in various evolutionary stages. In order to investigate the nature of mid-IR sources, we have performed photometry of MIPSGAL data, and we present a catalogue of YSOs combining other available point source catalogues from optical to IR. We discuss the evolutionary stages and characteristics of YSOs from their IR colors and spectral energy distributions.

• Current Optics and Photonics
• /
• 제2권6호
• /
• pp.576-581
• /
• 2018

A new approach for identification of a microwave frequency using an integrated optical waveguide chip, combined with a phase modulator (PM) and two microring resonators (MRRs), is proposed, theoretically deduced, and verified. By wavelength tuning to set the PM under the condition of a double side band (DSB), the measurement range can be started from the dc component, and the measurement range and response slope can be adjusted by designing the radius and transmission coefficient of the MRR. Simulations reveal that the amplitude comparison function (ACF) has a monotonic relationship from dc to 32.5 GHz, with a response slope of 5.15 dB under conditions of DSB modulation, when the radius values, transmission coefficients, and the loss factors are designed respectively as $R_1=400{\mu}m$, $R_2=600{\mu}m$, $t_1=t_2=0.63$, and ${\gamma}_1={\gamma}_2=0.66$. Theoretical calculations and simulation results both indicate that this new approach has the potential to be used for measuring microwave frequencies, with the advantages of compact structure and superior reconfigurability.

• 천문학회보
• /
• 제37권2호
• /
• pp.99.2-99.2
• /
• 2012

We updated the far-ultraviolet (FUV) spectral images of the entire Vela supernova remnant (SNR) using newly processed FIMS/SPEAR data. In the present study, we compare the newly produced FUV images with the X-ray and $H{\alpha}$ images, and examine how the Vela SNR evolves and interacts with the ambient medium on a global scale. The comparison with X-ray images has revealed a FUV filamentary feature corresponding with the boundary of the northeast-southwest asymmetry of the X-ray shell. The relatively low O IV] ${\lambda}1404$ to O III] ${\lambda}{\lambda}1661$, 1666 ratio estimated on the FUV filament is compatible with the previous proposal that the observed asymmetry of the Vela SNR could be due to the ${\gamma}2$ Velorum stellar wind bubble (SWB). The southwest FUV features surrounding a faint extended X-ray region are characterized as the region where the Vela SNR is interacting slightly stronger with ambient mediums within the dim X-ray southwest section. From a comparison with the $H{\alpha}$ image, we identify a ring-like $H{\alpha}$ feature overlapped with an extended hot X-ray feature of similar size and two local peaks of C IV ${\lambda}{\lambda}1548$, 1551 emission. Their morphologies are consistent with the expected shape when the $H{\alpha}$ ring is in direct contact with the near or far side of the Vela SNR. We suggest that the B3V-type star HD 76161 found at the center of the $H{\alpha}$ ring would be the exciting source of the H II region.

• Journal of Radiation Protection and Research
• /
• 제18권2호
• /
• pp.1-16
• /
• 1993

급성 전신 및 부분 피폭시 피해자들에 대한 치료방침의 결정에 있어 참고자료로서 사용하기 위하여 저자들은 체외에서 말초혈액을 ${60}Co\;{\gamma}-$선으로 2Gy에서 12Gy까지 방사선 조사하여 말초 임파구에서 관찰되는 염색체이상의 빈도와 방사선량과의 관계를 실험적으로 연구하였다. 관찰된 세포중 불안정 염색체이상(dicentric 염색체, ring 염색체, acentric fragment쌍)이 나타난 세포의 비율은 2Gy에서 32%, 4Gy에서 47%, 6Gy에서 80%, 8Gy에서 94%, 10Gy이상에서는 100%였다. 급성 전신 피폭시 평균 흡수선량을 반영하는 지표인 Ydr은 2Gy에서 0.373, 4Gy에서 0.669, 6Gy에서 1.734, 8Gy에서 2.773, 10Gy에서 3.746 그리고 12Gy에서 5.454였다. 방사선량(D)과 염색체이상(dicentric염색체와 ring염색체의 합) 빈도(Ydr)와의 관계는 $Ydr=9.322{\times}10^{-2}/Gy{\times}D+2.975{\times}10^{-2}/Gy^2{\times}D^2$로 나타났다. 신체의 부분피폭시의 선량 및 과거의 피폭선량을 계산할 때 사용하는 지표인 Qdr은 2Gy에서 1.166, 4Gy에서 1.436, 6Gy에서 2.173, 8Gy에서 2.945, 10Gy에서 3.746, 그리고 12Gy에서 5.454였다. 이와 같은 선량측정방법의 신빙도를 검증하기 위하여 신체의 부분에 균일한 선량분포의 1.8Gy, 2.5Gy 및 7.0Gy의 방사선치료를 일회 받은 환자들로부터 구한 Qdr은 각각 1.109, 1.222, 2.222였으며 이로부터 $Qdr=Ydr/(1-e^{Ydr})$의 관계식을 이용하여 계산해 낸 피폭선량은 1.52Gy, 2.48Gy 및 6.54Gy로서 실제 조사한 선량과 매우 근사한 결과를 얻었다.

• 대한수학회지
• /
• 제42권2호
• /
• pp.203-222
• /
• 2005

Thompson series is a Hauptmodul for a genus zero group which lies between $\Gamma$o(N) and its normalizer in PSL2(R) ([1]). We construct explicit ring class fields over an imaginary quadratic field K from the Thompson series $T_g$($\alpha$) (Theorem 4), which would be an extension of [3], Theorem 3.7.5 (2) by using the Shimura theory and the standard results of complex multiplication. Also we construct various class fields over K, over a CM-field K (${\zeta}N + {\zeta}_N^{-1}$), and over a field K (${\zeta}N$). Furthermore, we find an explicit formula for the conjugates of Tg ($\alpha$) to calculate its minimal polynomial where $\alpha$ (${\in}{\eta}$) is the quotient of a basis of an integral ideal in K.

• 대한수학회보
• /
• 제44권2호
• /
• pp.379-383
• /
• 2007

We show that the modular equation ${\phi}^{T_n}_m$ (X, Y) for the Thompson series $T_n$ corresponding to ${\Gamma}_0$(n) gives an affine model of the modular curve $X_0$(mn) which has better properties than the one derived from the modular j invariant. Here, m and n are relative prime. As an application, we construct a ring class field over an imaginary quadratic field K by singular values of $T_n(z)\;and\;T_n$(mz).

• 대한수학회보
• /
• 제57권4호
• /
• pp.933-943
• /
• 2020

Let M be a Fano manifold, and H^🟉(M; ℂ) be the quantum cohomology ring of M with the quantum product 🟉. For 𝜎 ∈ H^🟉(M; ℂ), denote by [𝜎] the quantum multiplication operator 𝜎🟉 on H^🟉(M; ℂ). It was conjectured several years ago [7,8] and has been proved for many Fano manifolds [1,2,10,14], including our cases, that the operator [c₁(M)] has a real valued eigenvalue 𝛿₀ which is maximal among eigenvalues of [c₁(M)]. Galkin's lower bound conjecture [6] states that for a Fano manifold M, 𝛿₀ ≥ dim M + 1, and the equality holds if and only if M is the projective space ℙⁿ. In this note, we show that Galkin's lower bound conjecture holds for Lagrangian and orthogonal Grassmannians, modulo some exceptions for the equality.

• Archives of Pharmacal Research
• /
• 제19권1호
• /
• pp.71-73
• /
• 1996

The molecular structure of pirprofen, 3-chloro-4-(2,5-dihydro-1H-pyrrol-1-yl)-.alpha.-methyl-benzeneacetic acid, was determined by single crystal X-ray diffraction analysis. The compound was recrystallized from a mixture of chloroform and toluene in triclinic, space group P over $\bar1,\; with\; a=4.577(1),\; b=11.213(2),\; C=12.485(2){\AA},\alpa.=107.39(1),\;\beta=97.79(1),\;\gamma=92.03(2),\; and Z=2$ The calculated density is $1.384 g/cm^3$. The structure was solved by the direct method and refined by full matrix least-squares procedure to the final R value of 0.034 for 1681 independent reflections. The non-aromatic dihydropyrrol group is found to be coplanar to the central aromatic ring. The molecules are dimerized through the intermolecular hydrogen bonds at the carboxyl group in the crystal.