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Redetermination of di-ฮผ-sulfido-bisยญ{[(2R)-2-acetยญoxy-2-aminoยญethane-1-thiolยญato-ฮบ2 N,S]oxidomolybdenum(V)}
The structure of the title compound, [Mo2(C4H8NO2S)2O2S2], has been redetermined. Besides obvious differences between the original [Drew & Kay (1971 โถ). J. Chem. Soc. A, pp. 1851โ1854] and the current unit-cell parameters, some packing features of the structure are also different; these findings are the result of significant improvements in the precision and accuracy of the present structure analysis. The two Mo atoms in the dimeric complex have very similar distorted trigonalโbipyramidal environments. Each Mo atom is bonded to an S atom and to an N atom of an l-cysteine ester ligand, to a terminal O atom and to two S atoms which bridge to the adjacent Mo atom [MoโฏMo separation = 2.8191โ
(2)โ
ร
]. NโHโฏOcarbonยญyl and NโHโฏOterminal hydrogen-bonding interยญactions consolidate the crystal packing. During the synthesis, the originally employed l-cysteinate ligand has been converted to the l-cysteinate methyl ester ligand. Since this reaction does not take place without tin(IV) chloride, it is clear that tin(IV) chloride acts as a catalyst for the reaction
Tableau Formulas for One-Row Macdonald Polynomials of Types and
We present explicit formulas for the Macdonald polynomials of types and
in the one-row case. In view of the combinatorial structure, we call them
"tableau formulas". For the construction of the tableau formulas, we apply some
transformation formulas for the basic hypergeometric series involving very
well-poised balanced series. We remark that the correlation
functions of the deformed algebra generators automatically give
rise to the tableau formulas when we principally specialize the coordinate
variables
Experimental Studies on Xonotlite in the SiO2๏ผCaO๏ผH2O System: With Special Reference to the Spherical Secondary Particles
Synthetic xonotlite is one of the most important constituents of the industrial material for heat insulating and fire-resistant building materials. In this paper, formation mechanism of xonotlite as well as spherical secondary particle were experimentally examined in the SiO2โCaOโH2O system. Special attention was paid for the process of crystal growth and effects of the crystalline state of the starting materials. Effects of Al2O3 in the starting materials were also investigated using both pure and industrial materials. The products obtained were examined by X-ray diffraction and electron diffraction in addition to the detailed observations under the stereoscope and electron microscope. Amorphous to semi-crystalline state of CโSโH was characteristically formed at the initial stage of reaction and the morphology and the crystalline state of CโSโH varied complicatedly according to the experimental conditions.
The main results obtained are as follows: Morphology of CโSโH and its aggregate depend largely upon the crystalline state of the starting materials. In the experiments used Brazilian quartz as source of silica, fine and fibrous CโSโH is aggregated, forming angular surfaced massive agglomerate. Using silica gel (reagent), fine aggregate particle of crumpled foil of CโSโH is entangled with long and fibrous CโSโH, resulting in an irregular massive agglomerate. Most of CโSโH formed in the Brazilian quartz system transform to platy tobermorite and to strip and needle crystals of xonotlite through platy tobermorite as reaction proceeds, and simultaneously massive agglomerate of slightly rounded form changes to oolitic (A1) and spherical-shelled (A2) secondary particles. The formation process of the spherical secondary particle composed of xonotlite is basically the same as that when industrial silica powder (ฮฑ-quartz) containing a very small quantity of Al2O3 is used. With increasing particle size of CaO, hollow spherical secondary particles change to those of dense aggregates composed of needle crystals of xonotlite (A3) through the spherical shell (A2) and oolitic (A1).
In the experiments used silica gel (reagent), CโSโH transforms directly to needle crystal of xonotlite which aggregates in the forms of bundle or irregular massive agglomerate, and no spherical agglomerate is formed. With rising temperatures, however, prisms of hillebrandite are partly formed and transform to xonotlite, forming the spherical secondary particle (B1) composed of extremely coarse aggregates with long needle xonotlite on the surface. By addition of very small amount of Al2O3, spherical secondary particles are formed in such a way that long fibrous CโSโH formed at the initial stage of the reaction becomes gradually short resulting the number of bundled aggregates decrease and then, as the reaction proceeds, the platy crystal of tobermorite is partly formed which later transforms into xonotlite forming spherical secondary particles. The secondary particle is composed of relatively coarse aggregates of needle crystals (B2). The spherical secondary particle is unevenly hollow and has long needle crystals on the surface. To be noted is that the texture and morphology of these spherical secondary particles are similar to those produced in the industrial processes when byproduct amorphous silica containing a very small quantity of Al2O3 is used.
The spherical secondary particle of types A1, A2, B1 and B2 play an important role producing light-weighted products suited for insulation and heat insulating materials and that of A3 is suited for fire-resistant building materials because of the high density property. Aggregates composed of the needle crystals of xonotlite do not form the secondary particle and the products have drawbacks such as poor mouldability and contraction and distortion during the drying. These aggregates could not be used as the industrial materials
Effect of Various Factors on Transverse Shrinkage under Butt Welding(Mechanics, Strength & Structure Design)
2,4-Dibromo-6-[(quinolin-8-ylยญamino)ยญmethylยญidene]cycloยญhexa-2,4-dien-1-one monohydrate
In the title compound, C16H10Br2N2OยทH2O, bifurcated intraยญmolecular NโHโฏ(N,O) hydrogen bonding defines the essential planarity of the main molยญecule: the dihedral angle between the quinoline and benzene rings is 7.53โ
(8)ยฐ. Interยญmolecular OโHโฏO and weak CโHโฏO hydrogen bonds consolidate the crystal packing, which exhibits ฯโฯ interยญactions with a distance of 3.588โ
(1)โ
ร
between the centroids of the aromatic rings and short BrโฏBr contacts of 3.5757โ
(6)โ
ร
ใณใฆใช ใ ใดใจใฆใญใณ ใฐใฉใคใน ใทใญ ใ ใคใฏใด ใ ใฒใณใด ใใงใฆใฒใณ ใ ใดใซใค ใฆใฆใญ ใณใฆใซ
ๆฌ่ซๆใฎ็ฎ็ใฏใGrice(1975)ใซใใใ maxim ใฎ่จณ่ชใจใใฆไฝฟใใใฆใใใๅ
ฌ็ใใฎ่ๅฏใ้ใใฆใใ็ฟป่ปขๆณใใซ่ตทๅ ใใๆ
ๅ ฑไผ้ไธใฎๅ้กใจใๅฏ่ฝใชๅฏพๅฆๆณใ็คบใใใจใงใใใใๅใใใฎใซ็ญใใใใฎใฏใพใไบใใซ็ญใใใใใซใใใฆใฏใไธกไธ็ท้จใฎ้ใงๆฐใฎ่ปขๆใ่ตทใใฆใใใใใฎใใใช่จ่ใฎไฝฟใๆนใใๆฌ่ซๆใงใฏใ็ฟป่ปขๆณใใจๅผใถใๆฐๅญฆๆ่ฒใซๆบใใๆฅๆฌไบบ็ ็ฉถ่
ใ้ๆ่ญ็ใซไฝฟใ็ฟป่ปขๆณใฏใใใฐใใฐ็่งฃใ่ใใๅฆจใใใใใใใใmaxim ใฎ่จณ่ชใจใใฆใๅ
ฌ็ใใไฝฟใใชใใ็กๆจใฎใๅ
ฌ็ใใจใฎ้ใใๅฟตๅ
ฅใใซ่ชฌๆใใๅฟ
่ฆใใใใใใใชใใจใๅฝไปคใจ้ณ่ฟฐใฎ้ใงๅญฆ็ฟ่
ใๆททไนฑใใ่ชค่งฃใใใใจใซใชใใใญใชใใใๅ
ฌ็้ๅใใจใใ้ฃ็ตใฏ็กๆจใฎใๅ
ฌ็ใใงใฏ่ตทใใซใใไบๅฎใ่ฆ้ใใฆใฏใชใใชใใใใใใซๆณจ็ฎใใใจใAustin(1962)ใฎ่จ่ช่ก็บ่ซใจ้ฃๅใใใ่จ่ชๅฏพๅฟ่ซใใๆงๆณใใใใ็ฟป่ปขๆณใซ่ตทๅ ใใๅ้กใฎ็บ็ใฏใใใ็จๅบฆใๅญฆๆ กๆ่ฒใงไบ้ฒใใใใจใๅฏ่ฝใงใใ
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