• Proceedings of the Korea Crystallographic Association Conference
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• 2003.05a
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• pp.17-17
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• 2003

tRNA (m¹ G37) methyltransferase (TrmD) catalyze s the trans for of a methyl group from S-adenosyl-L-methionine (AdoMet) to G/sup 37/ within a subset of bacterial tRNA species, which have a residue G at 36th position. The modified guanosine is adjacent to and 3' of the anticodon and is essential for the maintenance of the correct reading frame during translation. We have determined the first crystal structure of TrmD from Haemophilus influenzae, as a binary complex with either AdoMet or S-adenosyl-L-homocysteine (AdoHcy), as a ternary complex with AdoHcy/phosphate, and as an apo form. The structure indicates that TrmD functions as a dimer (Figure 1). It also suggests the binding mode of G/sup 36/G/sup 37/ in the active site of TrmD and catalytic mechanism. The N-terminal domain has a trefoil knot, in which AdoMet or AdoHcy is bound in a novel, bent conformation. The C-terminal domain shows a structural similarity to DNA binding domain of trp or tot repressor. We propose a plausible model for the TrmD₂-tRNA₂ complex, which provides insights into recognition of the general tRNA structure by TrmD (Figure 2).

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.969-972
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• 2003

The overall aim of this paper is to determine coupling loss factor of welding point between shell and cylinder using loss factor and structural loss factor. For this purpose, two kinds of loss factor were adopted. One is loss factor of each sub structure, another is structural loss factor based on the complex welded or assembled structure. Using these two parameters, it is possible to derive the coupling loss factor which represent characteristic condition of SEA theory. Coupling loss factor of conjunction in complex structure was expressed as power balance equation. The derived equation for a coupling loss factor has been simplified on the assumption of one way(nl- directional) power flow between multi-sub structures. Using these conditions, it is possible to find the equation of coupling loss factor expressed as above two loss factors. To check the effectiveness of above equation, this paper used two stage application. The first approach was application between simple cylinder and shell. The next was adopted rotary compressor. Rotary compressor has three main conjunctions between shell and internal vibration part. This equation was applied to find out the optimum welding Point with respect to reduce the noise propagation. It shows the effective tool to evaluate the coupling loss factor in complex structure

• Bulletin of the Korean Chemical Society
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• v.20 no.7
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• pp.791-795
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• 1999

The crystal structure of a cyclopropane sorption complex of dehydrated fully Ca (2+) -exchanged zeolite X, Ca46Si100Al92O384· 30C3H6 (a = 24.988(4) Å), has been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd3 at 21(1)℃. The crystal was prepared by ion exchange in a flowing stream of 0.05M aqueous Ca(NO3)2 for four days, followed by dehydration at 460℃ and 2×10 (-6) Torr for two days, and exposure to 100 Torr of cyclopropane gas at 21(1)℃. The structure was determined in this atmosphere and refined to the final error indices R1 = 0.068 and R2 = 0.082, with 373 reflections for which I > 3σ (I). In this structure, Ca 2+ ions are located at two crystallographic sites. Sixteen Ca 2+ ions fill the octahedral sites I at the centers of the hexagonal prisms (Ca-O = 2.412(9)Å). The remaining 30 Ca 2+ ions are at sites Ⅱ; each extends 0.46Å into the supercage (an increase of 0.16Å upon C3H6 sorption) where it coordinates to three trigonally arranged framework oxygens at 2.311(8)Å. Each of the 30 cyclopropane molecules was found to complex to Ca 2+ ions at site II by the induced dipole interaction (Ca-C = 2.99(4)Å). All carbon atoms in each cyclopropane molecule are equivalent and equidistant from Ca 2+ ions at site II with which they are associated.

• Analytical Science and Technology
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• v.20 no.4
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• pp.355-360
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• 2007

The title complex, $(C_3H_{12}N_2)[\{Cd(H_2O)(C_6H_5O_7)\}_2]{\cdot}6H_2O$, I, has been prepared and its structure characterized by FT-IR, EDS, elemental analysis, ICP-AES, and X-ray single crystallography. It is triclinic system, $P{\bar{1}}$ space group with a = 10.236(2), b = 11.318(2), c = $13.198(2){\AA}$, ${\alpha}=77.95(1)^{\circ}$, ${\beta}=68.10(1)^{\circ}$, ${\gamma}=78.12(1)^{\circ}$, V = $1373.5(3){\AA}^3$, Z = 2. Complex I has constituted by protonated 1,3-diaminopropane cations, citrate coordinated cadmium(II) anions, and free water molecules. The central cadmium atoms have a capped trigonal prism geometry by seven coordination with six oxygen atoms of three different citrate ligands and one water molecule. Citrate ligands are bridged to three different cadmium atoms. Each cadmium atom is linked by carboxylate and hydroxyl groups of citrate ligand to construct an one-dimensional ladder-type assembly structure. The polymeric crystal structure is stabilized by three-dimensional networks of the intermolecular O-H${\cdots}$O and N-H${\cdots}$O hydrogen-bonding interaction.

• East Asian mathematical journal
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• v.40 no.1
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• pp.1-23
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• 2024

Let M be a semi-invariant submanifold of codimension 3 with almost contact metric structure (𝜙, 𝜉, 𝜂, g) in a complex space form M_n+1(c). We denote by A, K and L the second fundamental forms with respect to the unit normal vector C, D and E respectively, where C is the distinguished normal vector, and by R_𝜉 = R(𝜉, ·)𝜉 the structure Jacobi operator. Suppose that the third fundamental form t satisfies dt(X, Y) = 2𝜃g(𝜙X, Y) for a scalar 𝜃(≠ 2c) and any vector fields X and Y , and at the same time R_𝜉K = KR_𝜉 and ∇_{𝜙∇𝜉𝜉}R_𝜉 = 0. In this paper, we prove that if it satisfies ∇_𝜉R_𝜉 = 0 on M, then M is a real hypersurface of type (A) in M_n(c) provided that the scalar curvature $\bar{r}$ of M holds $\bar{r}-2(n-1)c{\leq}0$.

• Journal of the Korean Mathematical Society
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• v.43 no.6
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• pp.1289-1300
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• 2006

It is well known that the twistor, section of twistor space, classify the orthogonal almost complex structure on even dimensional Riemannian manifold (X, g). We will show that existence of a harmonic and anti-holomorphic twistor is equivalent to having a symplectic structure on (X, g).

• Journal of Korean Society of Forest Science
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• v.85 no.1
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• pp.1-14
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• 1996

The object of this study was to examine the effects of air pollution on forest vegetation structure in the vinicity of Sasang industrial complex in Korea. Forest vegetation structure was investigated at 19 sample plots surrounding industrial complex and at one site away from industrial complex as a control. The results obtained were as follows; 1. For analysis of vegetation structure, upperstory of forests was mostly consisted of Pinus thunbergii, and partly of Alnus firma and Robinia pseudoacacia. In midstory, major components were Pinus thunbergii, Robinia pseudoacacia, Rhus trichocarpa, Rhus chinensis and Styrax japonica, In lower story, Pinus thunbergii was a minor component, while Robinia pseudoacacia, Quercus serrata, Rhus trichocarpa. and Rhododendron yedoense var. poukhanense which were known to be resistant to air pollution were found in large number. Especially, importance percentage of Robinia pseudoacacia was high, while that of Rhododendron mucronulatum was low in surrounding industrial complex. 2. For woody plants, number of species, species diversity and similarity index in industrial complex, were not significantly different from those in control plot. 3. For herbs, Oplismenus undulatifolius appeared in large number in most plots. The $SDR_3$ of Miscanthus sinensis, Calamagrostis arundinacea, Paederia scandens, Spodiopogon cotulifer and Carex humilis were high, but that of Aster scaber, Saussurea seoulensis, Solidago virgaaurea var. asiatica and Prunella vulgaris var. lilacina were low in the vicinity of industrial complex. 4. Number of herb species decreased to below 10 species at surrounding industrial complex as compared to 20 species in the control plot. In addition species diversity, and similarity index in the industrial complex were lower than those in control plot. It may be concluded that Pinus thunbergii forests in industrial complex consists of tree species resistant to air pollution, and that composition of woody vegetation in industrial complex was not much different from control plot, while composition of herbs was already quite different between the two plots. Forest vegetation structure, therefore, may change with time due to air pollution in the industrial complex.

• Journal of the Korean Mathematical Society
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• v.50 no.2
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• pp.231-240
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• 2013

We discuss the integrability of orthogonal almost complex structures on Riemannian products of even-dimensional round spheres and give a partial answer to the question raised by E. Calabi concerning the existence of complex structures on a product manifold of a round 2-sphere and of a round 4-sphere.

• YAKHAK HOEJI
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• v.7 no.1
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• pp.1-7
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• 1963

This investigation is the studies on the solubility analysis for several pharmaceuticals. The equilibrium reactions leading to complex formation of Caffeine and Nicotinamide with Lidocaine and Saccharin have been studied. The equilibrium constant of each complexes have also been calculated. It is shown that complex formation may lead to an increase in the solubilities of the reactants, and that Nicotinamide has more complexing activity than Caffeine. The influence of chemical structure of each components on interaction is also discussed.

• Bulletin of the Korean Chemical Society
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• v.17 no.9
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• pp.836-839
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• 1996

A new copper complex containing 2,2'-dipyridylbenzamide(dpba), Cu(dpba)(NO3)2(CH3CN), has been synthesized and characterized. The crystal structure has been determined. Crystal data: space group P212121, Z=8, a=13.911(3) Å, b=16.813(3) Å, c=18.932(3) Å, V=4427.9(1) Å3 and R=0.0674 for 1716 reflections. The copper environment is square pyramidal containing acetonitrile in axial site. Spectroscopic properties has been characterized in solution state. The redox property of the Cu(dpba)(NO3)2 complex is different from that of corresponding copper-dpa complex.