H₂S sensing properties of p-type SnO and Cu₂O oxide semiconductors

허영우,Vu Xuan Hien,Tien Pham Hung 한국표면공학회 2018 한국표면공학회 학술발표회 초록집 Vol.2018 No.11

개질섬유에 관한 연구 (I)

허영우 한국섬유공학회 1969 한국섬유공학회지 Vol.6 No.1

In order to investigate the improvement of alginate fibers some blended yarns were prepared with sodium alginate (SA) and polyvinylalcohol (PVA), using an coagulation bath of 33% calcium chloride and sodium chloride. Blended yarns were treated with variuos acetalization bath (60 min. immersion in 10% formaldehyde, acetaldehyde, butylaldehyde and benzoaldehyde solution and in acetylation bath of acetic anhydride 3.1 mol/ι), zinc choloride (1.3 mol/ι) as a catalyzer. Some Properties such as dry or wet elongation and strength were measured and specially some results were obtained in this ivestigation.

유화중합에 의한 폴리작산비닐의 분자양측정에 관한 연구

허영우 한국섬유공학회 1969 한국섬유공학회지 Vol.6 No.2

Polyvinyl acetate obtained by emulsion polymerization was fractioned by Baker and William's type column fraction method and the results of fraction were discussed. Acetone-water mixture was used as the solvent and sea sand (15∼20mesh) as the column carrier. Ne number average molecular weights(Mn) of fraction were determined by osmotic pressure method at 37℃ and weight average molecular weights(Mw) were determined by light setting method at 25℃ The intrinsic viscosity measurements were taken at various temperatures and the following equations were obtained fractionated PVAc in acetone solution at various temperature. 〔η〕=5.93×10-4Mn0.62 (30℃, Acetone) 〔η〕=3.66×10-4Mn0.65 (37℃, Acetone) 〔η〕=5.22×10-4Mn0.61 (30℃, Acetone)

합섬 섬유의 결정성문제에 대하여

허영우 한국섬유공학회 1966 한국섬유공학회지 Vol.3 No.2

Polymer Blend에 의한 합성섬유용호제의 대전방지효과에 관한 연구

허영우 한국섬유공학회 1970 한국섬유공학회지 Vol.7 No.1

Partial saponification of polyvinyl acetate with sodium hydroxide or potassium hydroxide was carried out in acetone-water (7/3, V/V) mixture, and the effect of the above two alkalies were compared. In order to investigate the sizing effect of sodium alginate for the use of synthetic fibers, the amount of size, elongation and strength of sized yarn were examined. It was found that the treated nylon and polyester filament yarns prepared from polyvinyl alcohol and Na-alginate had better qualities as anti-static agent.

Polyethylene Terephthalate의 열적 처리조건이 물성 및 결정구조 변화에 미치는 영향

허영우,최영화 한국섬유공학회 1977 한국섬유공학회지 Vol.14 No.2

The effect of drawing and heat treatment for PET chip and filament on the thermal characteristics, long period and fine structure were studied. Abnormal volume expansion displayed at around 200$^{\circ}C$ corresponds with works by Ueberreiter. Determination of specific heat and D.T.A. thermogram provides endothermic changes to show the abnormal volume expansion. In the course of gradual increasing of temperature (0.5$^{\circ}C$/min), long period shows minimum value of 100${\AA}$ near 140$^{\circ}C$ and it increases up to 125${\AA}$ representing thickening of the crystal lamella with increasing temperature up to 220$^{\circ}C$. Thickening mechanism of the lamella can be explained by the sliding diffusion theory, however, it is considered to be reasonable to interpret it as the molecular fractionation. Crystalization energy decreases with increase in draw ratio and deflection point can be found at draw ratio of 2.2, where crystallization energy decreases rapidly. Two peaks are shown at the D.T.A. thermogram of the melting point. The peak of the lower temperature one can be considered as the unstallized part susceptible to be rearranged.

난연처리 면섬유의 난연성능과 열분해거동에 관한 연구

허영우,송석규 한국섬유공학회 1975 한국섬유공학회지 Vol.12 No.2

The flame-retardant properties and thermal behavior of cotton finished with some selected flame retardants, organic nitrogen compound, organic phosphorus compound and inorganic halogen compound etc. were investigated. Total add-on of finish were determined and flammability properties were evaluated by the 45$^{\circ}$ angle method. Thermogravimetric analysis were used to study the thermal behavior of the cotton during pyrolysis. The thermogravimetric analysis curves were evaluated quantitatively for activation energy, total weight loss and char remaining after pyrolysis, and peculiarity point of pyrolysis. A study of the kinetics of decomposition for these systems indicates that activation energy was found to decrease with increasing flame retardency and an inverse relationship between activation energy and the residue remaining after pyrolysis was observed. Further, it has been observed that the addition to cellulose of any of the compounds lowers the onset temperature of decomposition and the temperature at which the first major weight loss begins, and the temperature decrease varies from compound to compound.

난연화 섬유의 열분석에 관한 연구 (제3보) -견섬유의 티탄염 흡착거동과 방염효과-

허영우,송석규 한국섬유공학회 1976 한국섬유공학회지 Vol.13 No.1

Titanium salt adsorption behaviors in the citric acid aqueous solution on domestic silk fabric and its effects on flame retardancy were examined. For the evaluation of flame retardancy, the following methods were used: 45$^{\circ}$ angel burn test, thermal gravimetric analysis (TGA) and differential thermal analysis (DTA). The results are as follow. 1. The adsorbed amount of titanium salt on silk fabric is varied to some extent with the treating conditions, thus, salt increased with increassing of treating temperature, time and citric acid concentration of solution. 2. Titanium salt are effectual for flame retardancy on silk at smaller add-on as on wool but Zirconium salt are not so effectual as titanium salt. 3. It has been observed that titanium salt lower the onset temperature of phyrolysis and in crease char amount after pyrolysis. 4. The peaks of pyrolysis velocity (dw/dt) obtained from plots of dw/dt vs temperature were some what shifted to higher temperature in contrast with that of untreated silk. 5. All the silk fabrics show an initial endothermic reaction at about 100$^{\circ}C$ on account of the evaporation of absorbed water. The second endothermic peaks appear at 310∼315$^{\circ}C$ according to the titanium salt add-on amount. 6. It have the tendency to decrease the specific reaction rate constant and activation energy according to the titanium treatment. Its values are decreased with the increase of the titanium salt add-on.

Effects of Codoping with Fluorine on the Properties of ZnO Thin Films

허영우,D. P. Norton 한국세라믹학회 2006 한국세라믹학회지 Vol.43 No.11

We report on the effects of co-doping with fluorine on properties of ZnO thin films grown by pulsed-laser deposition. The transport characteristics of Ag-F and Li-F codoped ZnO films were determined by Hall-effect measurements at room temperature. Ag-F codoped ZnO films showed n-type semiconducting behaviors. An ambiguous carrier type was observed in Li-F codoped ZnO films grown at a temperature of 500oC with the oxygen pressures of 20 and 200 mTorr. The qualities of the codoped ZnO films were studied by X-ray diffraction, atomic force microscopy, X-ray photoemission spectroscopy, and photoluminescence.

GPC에 의한 폴리초산비닐의 분자량 및 분자량분배 측정에 관한 연구

허영우,김진우 한국섬유공학회 1970 한국섬유공학회지 Vol.7 No.2

Molecular weight and its distribution of polyvinyl acetate synthesized by emulsion polymerization method were studied by gel permeation chromatography and column fractionation method. It was attempted to obtain the linearity of calibration curve, four different permeability gel packed column were connected in GPC measurement. The concentration of 0.1g/100ml of standard material was used to apply the calibration curve for a wide range of molecular weight determination. In the fractionation method, fractionation data were plotted according to Schulz plotting method. It was found that the results obtained by fractionation method was relatively in good agreement with those of GPC area method but not with those GPC line method.