• Geosystem Engineering
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• v.21 no.5
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• pp.291-296
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• 2018

The aim of this work is to study the effect of aggregate type on the physico-mechanical properties and microstructure of bio-mortar (BM). Three different aggregates such as sand, dolomite and basalt were used. BM was prepared by mixing aggregates with bacterial cells (Sporosarcina Pasteurii) and one equimolar (1 M) of $urea/CaCl_2.2H_2O$. The results proved that the chemical composition and physical properties of aggregates play an important role in the microbial precipitation rate as well as size, morphology and crystallinity of the precipitated calcite, which strongly reflects on the properties of the prepared BM. The BM containing dolomite gave the highest compressive strength and lowest water absorption.

• Bulletin of the Korean Chemical Society
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• v.15 no.3
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• pp.214-221
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• 1994

We present some results obtained from theoretical study on a non-symmetrical A/BC polymeric system including solvent which consists of two phases, a polymeric phase A on one side and a mixture of polymers B (as a compatibilizer) and C on the other in the presence of a solvent. By employing the functional integral techniques we derive the mean-field equations and solve them numerically to deduce the physical properties of the interface involving the polymers and solvent concentration profiles in the limit that molecular weights of all the polymers involved tend to infinity. The calculations are performed for typical values of the Flory interaction parameters and for the volume fraction of polymer B in the asymptotic phase and of solvent. In the polymers/solvent blend under consideration the interfacial adsorption of polymer B, the solvent concentration, and degrees of the specific interaction between the polymers are found to play important roles in modification of the interfacial properties.

• Bulletin of the Korean Chemical Society
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• v.9 no.4
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• pp.244-248
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• 1988

Multilayer adsorption isotherms of nitrogen on hexagonal boron nitride, ${\gamma}$-alumina, and silica-gel powders are determined at the liquid nitrogen temperature using a gravimetric adsorption apparatus. The volume (V) of the adsorbed gas are plotted against the statistical thickness(t) of the adsorbed layer, and the t-method area are calculated from the slope of these V-t plots to compare with the BET area. A number of universal adsorption isotherms and the Frenkel-Halsey-Hill equation are used one after another in calculating the statistical thickness. The appropriateness of the FHH equation as an universal adsorption isotherm is discussed finally.

• Bulletin of the Korean Chemical Society
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• v.10 no.4
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• pp.343-346
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• 1989

Dicyclohexyltin(IV) complexes $Cy_2SnX (X = O,\;S,\;(Me_2NCS_2)_2)$ have been prepared and characterized by means of elemental analysis, cryoscopic data, and IR spectroscopy. X-ray structure determination for $Cy_2Sn(S_2CNMe_2)_2$ (monoclinic; P2/c;a = 8.992(1), b = 6.688(1), c = 19.453(2) ${\AA},\;{\beta}$ = 96.556(7) ; R = 0.041) has shown that the molecule is $C_2$-symmetric with both dithiocarbamate ligands bonding in anisobidentate mode and the local geometry around the hexacoordinate Sn(IV) atom is a distorted octahedral arrangement with the two cyclohexyl groups in trans position. The physical and chemical properties measured suggest polymeric and trimeric structures for $Cy_2SnO\;and\;Cy_2SnS$, respectively.

• Journal of the Korean Chemical Society
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• v.58 no.4
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• pp.381-387
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• 2014

A series of new $N^7$-tetrazolo[5,1-f ]-1,2,4-triazin-8-(7H)-one derivatives 4-16 were designed and synthesized from 3 with different reagents. The newly prepared compounds were characterized by spectral data and screened for their antimicrobial activities against various bacteria and fungi strains.

• Natural Product Sciences
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• v.2 no.2
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• pp.102-105
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• 1996

A new glycolipid, 2-hydroxy-3 $(octadecyloxy)-propyl-{\alpha}-D-arabinopyranoside$ (1) has been isolated from Lobophytum microlobulatum and its structure has been elucidated by physical and spectral $(UV,\;IR,\;^1H,\;^{13}C\;NMR,\;FABMS)$ data.

• Journal of the Korean Chemical Society
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• v.16 no.3
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• pp.178-188
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• 1972

Diethyl itaconate was found to react tetrafluoroethylene, trifluorochloroethylene, and 1,1-difluoro-2,2-dichloroethylene quite rendily at $180^{\circ}C$ to form 1-carboxy-2,2,3,3,-tetrahalo-cyclobutane ethanoic acid derivatives ${C{\underline{X_2-CF_2-CH_2-}}C-(COOEt)-CH_2COOEt$, where X is Cl or F). Diethylcitraconate failed to yeild any cycloaddition products. The Physical and Chemical properties of the above esters and their dericatives are characterized and compared with other similar ring compounds.

• Bulletin of the Korean Chemical Society
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• v.26 no.2
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• pp.292-296
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• 2005

Physical and chemical properties of thexylboronic acid and its derivatives such as thexylboroxine and ethylene glycol or diethanolamine thexylboronic ester have been studied. Thexylboronic acid can be extracted from an organic solution with an aqueous sodium hydroxide solution as an “te”complex. It is readily converted into thexylboroxine in the presence of anhydrous magnesium sulfate in pentane. It reacts with simple alcohols only slowly; however, it reacts readily with excess diethanolamine in the presence of anhydrous magnesium sulfate to give the corresponding ester.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.483-486
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• 2002

Tree-ring types liquid crystalline compounds having fluoro and isothiocyanate substituent[1] were synthesized and their physical properties were measured to evaluate the applications to TFT-LCD TV. All synthesized compounds were showed remarkably high Tni point. Birefringence(${\triangle}n$) and dielectric anisotropy(${\triangle}{\varepsilon}$) were higher than fluoro analogues and isothiocyanate substituted bicyclohexyl-phenyl compounds.

• Journal of the Korean Chemical Society
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• v.22 no.4
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• pp.229-238
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• 1978

Two methods for evaluation of the dipole moment matrix elements are developed, one using the expansion method for spherical harmonics and the other the transformation method of the dipole moment matrix elements into overlap integrals for Mulliken. The numerical values of the dipole moment matrix elements evaluated by two methods are in agreement with each other.