• Applied Chemistry for Engineering
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• v.10 no.2
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• pp.275-280
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• 1999

Cellulose has three hydroxyl groups with different reactivity. By substitution reaction, trimethylsiloxyl-, vinyldimethylsiloxyl-, allyldimethylsiloxyl-, phenyldimethylsiloxyl-, 3,3,3-trifluoropropyldimethylsiloxyl- and tris(trimethylsiloxy)siloxylcellulose were synthesized IR, NMR, and elemental analysis were used for confirming their structures, degree of substitution (D.S.) and the reactivity of siloxylation agent, respectively. The D.S. values were 2.5, 2.2, 2.1, 2.2, 2.6, 0.7 for the corresponding siloxylcellulose.

• Progress in Superconductivity and Cryogenics
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• v.25 no.4
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• pp.14-18
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• 2023

We have investigated the behavior induced by Ga substitution in B-1212 system and observed an anomalous superconductor-like resistivity drop with an onset near 260 K and an offset at 248 K in the nominal (B_0.65Ga_0.35)(Ba_1.25Sr_0.75)(Er_0.5Ca_0.5)Cu₂O_z compound. However, this property degraded with repeated cycling. Systematic studies of the superconducting properties of the (B_1-xGa_x)(Ba_1.25Sr_0.75)(Er_0.5Ca_0.5)Cu₂O_z compounds are reported and discussed in the context of the anomalous resistivity transition.

• Korean Journal of Materials Research
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• v.9 no.8
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• pp.787-791
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• 1999

TiB$_2$powders were prepared by mechanical alloying, and the effect of Zr and Ta substitution for Ti was investigated. It was possible to produce titanium diboride phase by mechanical alloying titanium and boron elemental powders for 280 hours. The amorphization reaction, a common process which occurs during mechanical alloying, has not been found. When zirconium of which atomic radius was larger than that of titanium was substituted for Ti, the alloying time was greatly reduced. On the contrary, substitution of tantalum for titanium prolonged the alloying time because of the less negative heat of formation of tantalum diboride than that of titanium diboride.

• Journal of the Korean Applied Science and Technology
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• v.15 no.2
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• pp.93-99
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• 1998

2-phenyl-N-methyl-1,3-thiazolium perchlorate(PTP)derivatives were synthesized via addition and substitution reactions. PTP was hydrolyzed under aqueous hydrochloride. The structures of the compounds were conformed by N.M.R.,I.R., and elemental analysis.

• Bulletin of the Korean Chemical Society
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• v.17 no.6
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• pp.525-528
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• 1996

Seven cali[4]arenes, having two different substituents in AAAB or AABB pattern at the upper rim of calix were synthesized by fragmentation condensation reaction of p-substituted phenol trimer (AAA) with 2,6-bishydroxymethylated 4-substituted phenol (B) or that of dimer (AA) with 2,2'-bishydroxymethylated dimer (BB). An equimolar mixture of the coupling components (trimer and monomer or dimer and dimer) was refluxed in dioxane in the presence of TiCl4to afford calix[4]arene 6 and 7 in 15-38% yield. The structure of calix[4]arenes was confirmed by elemental analysis and the 1H/13C NMR spectroscopy.

• Textile Coloration and Finishing
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• v.30 no.1
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• pp.29-37
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• 2018

Cotton has no adsorption ability for the cationic dye and heavy metal but, if anionized cotton can be made, it will be possible. In this study, to enable the anionisation of cotton fabric, it was modified using sodium vinylsolfonate(SV) as the anionisation reagent, employing a pad-dry-cure(PDC) technique. The effects of curing time, treatment concentrations of urea, sodium hydroxide and SV on the weight increase were experimented and then, the physical characterizations of sulfoethyl cotton(SEC) depending on the finishing conditions were estimated, thus the application possibility of SV as anionisation reagent was investigated. It was not much changed by anionisation except wrinkle recovery. And the structure of SEC was elucidated by Raman and NMR spectoscopy. The feasibility of using Raman and NMR spectroscopy with the band at $1,043cm^{-1}$, and 50.5ppm, respectively as marker band to determine sulfoethyl group of SEC was reported. The total degree of SV substitution(DSV) was determined via elemental analysis. SEC with diverse total DSV up to 0.066 was obtained. In the thermal decomposition(pyrolysis) by DSC, it can be found that the pyrolysis temperature was about $30^{\circ}C$ lower than that of non-treated cotton fabric.

• International Journal of Concrete Structures and Materials
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• v.8 no.1
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• pp.15-26
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• 2014

In order to study the capacities of a new occurrence of Brazilian clay samples as partial replacements of cement, a bentonite sample was selected for utilization in the natural and modified forms for present study. The natural bentonite (BBT) was modified by anchorament of 3-aminopropyltrietoxisilane ($BBT_{APS}$) and 3,2-aminoethylaminopropyltrimetoxisilane (BBTAEAPS) in the surface of component minerals of bentonite sample. The original and organo-bentonite samples were characterized by elemental analysis, scanning electron microscopic and textural analyses. The values of micropore area were varying from $7.2m^2g^{-1}$ for the BBT to $12.3m^2g^{-1}$ for the $BBT_{AEAPS}$. The bentonite samples were characterized by the main variable proportion of bentonite in the natural and intercalated forms (2, 5, 10, 15, 20, 25, 30, and 35 % by weight of cement) in the replacement mode whiles the amount of cementations material. The workability, density of fresh concrete, and absorption of water decreased as the substitution of ordinary Portland cement by perceptual of natural and modified bentonite increased. The results reveal that workability decreased with decrease of the amount of natural bentonite in the concrete, same behavior is observed for bentonite functionalized, varying from 49 to 28 mm. The energetic influence of the interaction of calcium nitrate in the structure of blends was determined through the calorimetric titration procedure.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.683-686
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• 2008

$\beta$-Glucans, which were isolated from sangwhang (Phellinus linteus), were subjected to reductive amination and the biological properties of the derivative were investigated. The degree of substitution of the aminated sangwhang $\beta$-glucan was calculated by elemental analysis to be 1.13. Bronchoalveolar lavage (BAL) experiments showed that the aminated derivative increased nitric oxide production. In addition, the amination enhanced in vitro cytotoxic activities against HT1080 and SNU-C2A cell lines. Thus, the aminated derivative is shown to enhance immune systems by the incorporation of amino groups into the polymer structure.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.1059-1064
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• 2001

This study is about accurate steel column position method in the Top down method's delicate part. When the concrete is placing, it is required that complementary measures to the transformation due to concrete pressure, column buckling, the trouble due to bar net inserting and so on. To solve the problem of exist method, the concrete is placed at the bottom of excavated hole in advance. then, the steel column is inserted into the excavated hole. With a new method try, the problem due to placing pressure and others is could be prevented. In this study, the concrete is examined with test-slump, slump flow, and compressive strength to do quantitative analysis of concrete. The factors of the experiment is plasticizer, retarder addition rate, fly ash substitution rate to cement. Considering of the new method try, the retarder added concrete properties-fluidity, viscosity, strength-is investigated as time lapsing.

• Bulletin of the Korean Chemical Society
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• v.35 no.7
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• pp.2077-2080
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• 2014

Cobalt-immobilized SBA-15 6a-c was synthesized from alkyne-attached SBA 5a-c by the reaction with $Co_2(CO)_8$ in toluene. Alkyne group was introduced into amino SBA-15 (4) by imine-linkage or substitution with propargyl bromide to afford iminoalkyne 5a and aminoalkyne 5b, respectively. Meanwhile, alkyne 5c was prepared in one-step by reacting triethoxysilyl hexyne with SBA-15. Dicobalt-complexes 6a-c were characterized by means of FT-IR, solid-state NMR and elemental analysis.