• Journal of Advanced Marine Engineering and Technology
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• v.7 no.1
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• pp.79-90
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• 1983

The examination for the changes of structures and mechanical properties in directionally solidified Al-Fe-Ni alloys containing the small amount of Fe and Ni was carried out by the varying the composition and solidification rate R of alloy, provided that the temperature gradient was 80 .deg.C/cm. The result were obtained as follows. A) In proportion to the increase of the solidification rate (R), the crystallized phase of this alloy was changed from the Ribbon-type structure to the Rod-type structure. B) The strength was rapidly increased in the changing process of composite shape from the Ribbon-type to the Rod-type with the solidification rate (R) increasing. C) The fiber stress (${\sigma}^f$) and Young's modulus ($E_f$) calculated for the Rod-type structure were 220 kg/$mm^2$ and 11, 800 kg/$mm^2$ respectively, which were in good accord with the rule of Mixtures.

• Bulletin of the Korean Chemical Society
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• v.19 no.10
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• pp.1095-1099
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• 1998

The crystal structure of an acetylene sorption complex of dehydrated fully Mn(Ⅱ)-exchanged zeolite X, Mn46Si100Al92O384·30C2H2 (a=24.705(3) Å) has been determined by single-crystal X-ray diffraction techniques. The structure was solved and refined in the cubic space group Fd3 at 21(l) ℃. The complex was prepared by dehydration at 380 ℃ and 2 x 10-6 Torr for 2 days, followed by exposure to 300 Torr of acetylene gas for 2 h at 24 ℃. The structure was refined to the final error indices, R1=0.060 and R2=0.054 with 383 reflections for which I > 3σ(Ⅰ). In the structure, Mn2+ ions are located at two different crystallographic sites; sixteen Mn2+ ions at site I are located at the centers of the double six rings and thirty Mn2+ ions are found at site Ⅱ in the supercage, respectively. Each of these latter Mn2+ ions is recessed ca. 0.385(2) Å into the supercage from its three-oxygen plane. Thirty acetylene molecules are sorbed per unit cell. Each Mn2+ ion at site Ⅱ lies on a threefold axis in the supercage of the unit cell, close to three equivalent trigonally arranged zeolite framework oxygen atoms (Mn(Ⅱ)-O=2.135(9) Å) and symmetrically to both carbon atoms of a C2H2 molecules. At these latter distances, the Mn(Ⅱ)-C interactions are weak (Mn(Ⅱ)-C=2.70(5) Å), probably resulting from electrostatic attractions between the divalent cations and the polarizable π-electron density of the acetylene molecules.

• Korean Journal of Crystallography
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• v.6 no.2
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• pp.63-68
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• 1995

The crystal structure of fenothiocarb(S-4-phenoxybutyl dimethylthiocarbamate), C13H19NO2S is monoclinic, space group P21/c, a=9.045(1)Å, b=14.577(2)Å, c=10.727(2)Å, β=103.56(1)°, Z=4, V=1375.20(6)Å3, Dc=1.23g/cm3, λ(Mo-Kα)=0.71069Å, μ=2.3cm-1, F(000)=544, temperature : 293±3K, R=0.049 for 1543 unique observed reflections. The structure was determined by direct method and refined by full-matrix least squares method. The molecules are contacted to the c axis with two fold screw and van der Waales force.

• Journal of the Korean Chemical Society
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• v.38 no.10
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• pp.769-773
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• 1994

Higher order structure of 5S rRNA isolated from Xanthomonas celebensis was examined using angiogenic extracted from milk. Angiogenin cleaved exclusively 3' P-O bonds on the far sides of pyrimidines in the single-stranded sequences of 5S rRNA. Whereas angiogenin acted only on the loop d of 5S rRNA at pH 7.0 in the presence of 10 mM $Mg^{2+}$, it acted on all the loops (a, b, c and d) except loop e in the absence of $Mg^{2+}$. In the absence of $Mg^{2+}$, bonds $U_{74}$-$G_{75}$, $U_{77}$-$A_{78}$ and $U_{103}$-$A_{104}$ were highly susceptible to the action of angiogenin both at pH 7.0 and at pH 3.5. On the other hand, at pH 3.5 in the absence of $Mg^{2+}$ angiogenin strongly cleaved the bond $C_{17}$-$G_{18}$ of loop a and the bond $U_{55}$-$G_{56}$ of loop b. The results lead us to the following conclusion. First, angiogenin can be used as one of the probes for the tertiary structure analysis of 5S rRNA. Second, the structure of loop d of 5S rRNA is variable depending on the concentrations of $Mg^{2+}$ and $H^{1+}$.

• Journal of the Korean Institute of Rural Architecture
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• v.17 no.4
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• pp.49-56
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• 2015

This study aims to identify variables (dependent and independent variables) by plane type and area, focusing on the R.C structure planes which were applied to the National Rental Housing Complexes during the 1970-80s; and to investigate differences in residential space compositions depending on the interrelationship between the variables. The results of this study can be summarized as follows: First, an independent variable which had the most influence on the residential space composition was found to be stairs. As dependent variables, bedroom, livingroom, and kitchen showed difference in spatial arrangements. Second, in the case of the front entry type, one-sided arrangements were the most common for the 3L+D.K composition, because livingroom was arranged near the stairs, Disadvantages were: (1) the spatial division of each room was not efficient; and (2) the use of room space was low due to long access to each room. Third, in the case of the rear entry type, no problem was found in arranging bedrooms on the front side. By arranging livingroom as a common space area, the distance of approachability to each room was found to be short and the use of space was excellent. However, disadvantages were: (1) stability was lacking; and (2) privacy was low. Fourth, depending on the location of the stairs, an interaction between bedrooms and the connectivity between livingroom and kitchen were found. Accordingly, there were differences in the size and arrangement of space by plane type.

• Bulletin of the Korean Chemical Society
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• v.16 no.6
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• pp.515-518
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• 1995

YSe1.83 was synthesized by vapor transport technique and its crystal structure was determined. The structure was isostructure of LaTe2-x, which was layered structure consisting of two-atom thick layers of YSe with distorted NaCl-type structure and one-atom thick layer of Se. The substructure of YSe1.83 was tetragonal with space group of P4/nmm and a=4.011(2) and c=8.261(3) Å with final R/Rw=6.4/6.9 %. The superstructure with asuper=2a, bsuper=6b and csuper=2c was found. The measurements of electronic and magnetic properties of this compound indicate that it is an electronic insulator and diamagnet.

• Proceedings of the Korea Concrete Institute Conference
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• 1990.10a
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• pp.179-184
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• 1990

This paper presents the recent repair and maintenance techniques of R/C structures in Korea. This paper consists of four parts : the first part introduces the current diagmosis techniques, the second one includes the repair methods and the third one classifies the repair material. Finally a repair case of the R/C structure in a chemical plant in Korea was introduced.

• Communications of the Korean Mathematical Society
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• v.13 no.3
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• pp.545-560
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• 1998

Let ø and A be denoted by the structure tensor field of type (1,1) and by the shape operator of a real hypersurface in a complex space form $M_{n}$ (c), c $\neq$ 0 respectively. The main purpose of this paper is to prove that if a real hypersurface in $M_{n}$ (c) satisfies $R_{ξ}$ øA = $AøR_{ξ}$, then the structure vector field ξ is principal, where $R_{ξ}$ / is the Jacobi operator with respect to ξ.

• Journal of Integrative Natural Science
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• v.9 no.4
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• pp.255-260
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• 2016

The crystal structure of the saliciline derivatives N,N'-bis(3-chloro-2-methylsalicylidene)-1,4-butanediamine ($C_{20}H_{22}Cl_2N_2O_2$) has been determined from single crystal X-ray diffraction data. In the title compound crystallizes in the triclinic space group $P{\bar{i}}$ with unit cell dimension $a=4.6085(3){\AA}$, $b=5.9747(3){\AA}$ and $c=5.9747(3){\AA}$ [${\alpha}=83.889(4)^{\circ}$, ${\beta}=86.744(5)^{\circ}$ and ${\gamma}=82.085(5)^{\circ}$]. The title compound is essentially planar conformation. The compound lies across a crystallographic inversion centre and adopts E configurations with respect to the C-N bonds. The crystal packing of the molecules of compound is stabilized through weak O-H...N intra molecular interactions

• Journal of the Korean Ceramic Society
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• v.12 no.3
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• pp.8-12
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• 1975

The crystal structure of synthetic magnesite has been studied by X-ray method. Magnesite is trigonal R3c, with a=4.637$\AA$, c=15.023$\AA$ and Z=6. Intensity data were collected with a Rigaku automated four-circle diffractometer and Mo-K$\alpha$ radiation. The structure was refined by the full-matrix least squares method using anisotropic thermal parameters. The final R index for 234 reflections is 0.037. The C-O and Mg-O bond lengths were 1.283 and 2.105$\AA$, respectively. The interatomic angles of three kinds of O-Mg-O were 88.25, 91.75 and 180.00$^{\circ}$, respectively. It is clarified that the distortion of the Mg-O6 octahedron in magnesite is smaller than that of Ca-O6 in calcite.