과형성 폴립과 유사한 모양을 보인 유경성 대장 평활근종의 내시경적 절제

박용완,조영석,김진수,손혜숙,김형근,김성수,채현석,최규용 대한소화기내시경학회 2008 Clinical Endoscopy Vol.37 No.3

위장관에서 발생하는 평활근종 중 대장 평활근종의 빈도는 3% 정도로 드물다. 대장 평활근종은 대장내시경검사 중 우연히 발견되는 경우가 많으며, 대부분 점막하 종양의 형태로 발견되지만 드물게 폴립의 형태를 갖는 경우도 있다. 대부분 외과적 절제가 확실한 치료이지만 유경성 또는 반유경성이면서 작은 폴립의 형태를 보이는 경우 내시경적 용종절제술로 치료할 수 있다. 저자 등은 무른변을 주소로 내원하여 시행한 대장내시경검사상 구불창자에서 짧은 경부를 가진 과형성 폴립의 모양을 보인 유경성 폴립을 발견하여 내시경적 폴립절제술로 제거하였고 조직검사를 통해 진단한 대장의 평활근종 1예를 경험하였기에 문헌고찰과 함께 보고한다.

투명 결정화 유리에 관한 연구 - $Al_2O_3-SiO_2$계에 관하여

박용완,김용욱 한국세라믹학회 1992 한국세라믹학회지 Vol.29 No.3

CaO and ZnO were added to Al2O3-SiO2 binary system respectively as flux, then ZrO2 and TiO2 were applied as nucleating agent to these CaO-Al2O3-SiO2 and ZnO-Al2O3-SiO2 ternary system glass. The transparency could not be kept in CaO-Al2O3-SiO2 system glass, whereas the transparent glass-ceramics were prepared in ZnO-Al2O3-SiO2 system glass containing ZrO2 as the nucleating agent. At this time the optimum heating temperatures for the nucleation and the crystal growth were 78$0^{\circ}C$ and 97$0^{\circ}C$. The sizes of the precipitated crystals in the transparent glass-ceramics were below 0.1 ${\mu}{\textrm}{m}$, and their light transmissibilities were more than 80%.

분상된 붕규산유리의 산처리에 관한 연구

박용완,신건철 한국세라믹학회 1975 한국세라믹학회지 Vol.12 No.2

The experiment has been carried out to clarify the condition of acid treatment for preventing the crack formation caused by swelling and shrinking during acid leaching process. The borosilicate glass contained phosphorous pentoxide was chosen as the sample, which is recognized to be more homogeneous in phase separation. The various effects, such as kind, cocentration and acid temperature, were investigated. The experimental results are summerized as follows. (1) Sulfuric acid is more stable than hydrochrolic acid for preventing the crack. (2) The optimum concentration of acid lies in the range of 0.1~0.3N. (3) Higher temperature of the acid to treat the separated glass was more stable than lower temperature. (4) The rate of crack decreased with the longer period and the higher temperature of the heat treatment.

고납유리의 X선 조사에 따른 Browning 현상에 관한 연구

박용완,강원호 한국세라믹학회 1983 한국세라믹학회지 Vol.20 No.3

The effects of the various amount of $CeO_2$ $MnO_2$ and $Fe_2O_3$ added to the high lead-silicate glasses on the X-ray induced coloration were studied. The light transmissions and chromaticities of the glasses before and after exposing to X-ray radiation were measured to investigate the effects by additivies. The results are as follows ; 1. High lead-silicate glass added $CeO_2$ or $MnO_2$ has a little effect on the transmission but has a considerable effect on the chromaticity. The chromaticies of 56.6wt% PbO content glasses were changed as 3-7 times as those of 28.3wt% PbO content glasses. 2. By the X-ray irradiation glasses containing 0.2-0.5wt% $CeO_2$ were changed the least in chromaticity that is the most effective in preventing the X-ray induced coloration. 3. By X-ray irradiation $MnO_2$ reduced the transmissions and showed purple coloration. 4. Transmission change amounts of the glasses added $CeO_2$ and $Fe_2O_3$ were less than those of the glasses added $CeO_2$ alone by X-ray irradiation.

결정화 유리에 관한 연구 저 Li$_2$O 유리에 관하여

박용완,이종근,고영신,김정은 한국세라믹학회 1976 한국세라믹학회지 Vol.13 No.1

In general the chemical composition of glass ceramics in Li2O-Al2O3-SiO2 system is similar to the composition of $\beta$-spodumene (Li2O-Al2O3-4SiO2). With the object to manufacture the glass ceramics which can be produced in the domestic pot the composition of glass was so settled at 1.0 Li2O.0.9Al2O3.6.0SiO2 in order to reduce the contents of Li2O, to prevent the corrosion of the pot and to decrease the cost of raw materials. 0.2 mole and 0.1 mole of the mixture of TiO2 and ZrO2 as nucleants were added to the basic composition of 1.0 Li2O-0.9Al2O3-6.0SiO2. Each sample was divided into two kinds with a TiO2/ZrO2 ratio of 2 to 1 and the other with a TiO2/ZrO2 ratio fo 1 to 1. Thermal expansion coefficient, the most important property of glass ceramics, was tested. The softening point and the melting point of the samples were observed by the use of a heating microscope. The results obtained were as follows. The manufacturing of glass ceramics seems to be possible in the industrial plant using the domestic pot. 1) The composition of the glass which can be melted in the domestic pot process was near 1.0 Li2O.0.9Al2O3.6.0SiO2. 2) The temperature range of crystal creation and crystal growth was between 850-94$0^{\circ}C$, and 5 hours holding the samples at the temperature range was enough to crystallize them. The major crystal was $\beta$-spdumene and there existed petalite partialy. 3) The thermal expansion coefficient fo the crystallized glass was negative. 4) The deforming point of the crystallized glass was 1435$^{\circ}C$.

$TiO_2$와 $ZrO_2$의 첨가에 따르는 $Li_2O-Al_2O_3-SiO_2$ 계 유리의 결정화에 관한 연구

박용완,전문덕 한국세라믹학회 1981 한국세라믹학회지 Vol.18 No.3

The effect of additions, $TiO_2$</TEx> and $ZrO_2$ as nucleant on the base glass which composition was determined to 0.97 $Li_2O-Al_2O_3-SiO_2$ has been investigated by means of D.T.A., X-ray diffraction and dilatation. $TiO_2$</TEx> and $ZrO_2$ as nucleant were added 0.06mole, in which ratios of $TiO_2$</TEx>/$ZrO_2$ were varied 1/0, 2/1, 1/1, 1/2 and 0/1. The crystalline phases were appeared to $\beta$-spodumene as principal, $\beta$-eucryptite and $ZrO_2$ as secondary, regardless of nucleant variations. The crystallinity of the crystallized glass added $TiO_2$</TEx>, $ZrO_2$ mixture as nucleant was higher than that of the glass added $TiO_2$</TEx> or $ZrO_2$ only. The crystallinity of the glass added $TiO_2$</TEx>/$ZrO_2$ =1/1 was highest. Increasing the addition of $ZrO_2$, it has been observed that the crystal growing temperature became higher.

고팽창 결정화 유리의 유약에 관한 연구

박용완,강은태,박찬성,전문덕 한국세라믹학회 1980 한국세라믹학회지 Vol.17 No.4

A glass-ceramics material of composition %SiO_2$: 38.50, $Al_2O_3$: 26.00, $Na_2O$: 18.00, CaO: 6.00, MgO: 4.00, $TiO_2$: 7.50 was strengthened by coating a series of glazes$(SiO_2-B_2O_3-Al_2O_3-CaO-PbO-Na_2O-)$, which has lower thermal expansion coefficient than that of the glass-ceramics. The thermal expansion coefficient of the glazes ranges $80~90{\times}10^{-7}$cm/cm/$^{\circ}C$, whereas that of the glass-ceramics is $115{\times}10^{-7}$cm/cm/$^{\circ}C$. The glass-ceramics was identified to be composed of nepheline, carnegieite low form, and meta sodium silicate crystal by X-ray diffraction phase analysis. The glaze, having lower melting point and appropriate thermal expansion coefficient, was tried to be stable and good at secondary heat treatment.

[특집/기술해설]광대역 이동 멀티미디어통신 기술 개요

박용완,정재윤,김재홍,문순주,이상연,김병무 대한전자공학회 1998 텔레콤 Vol.14 No.2

인산염계 다공질 결정화 유리에 관한 연구

박용완,현부성,김태호 한국세라믹학회 1995 한국세라믹학회지 Vol.32 No.7

A porous glass-ceramics body was prepared in the phosphate system. The glass composition of 47.2CaO-22.2TiO2-30.6P2O5 (mol%) containing a few weight percent of ZrO2 was suitable for a mother glass of a porous glass-ceramics. The dense glass-ceramics body was made by a two-step heat treatment of the mother glass. The crystalline phases of the glass-ceramics were $\beta$-Ca3(PO4)2 and CaTi4(PO4)6. The $\beta$-Ca3(PO4)2 phase could be selectively leached out with HCl solution and thus a crystalline $\beta$-Ca3(PO4)2 skeleton was remained. The dimension and shape of the porous glass-ceramics were nearly the same as the those of the first formed glass. The specific surface area and average proe radius of the porous glass-ceramics were 19$m^2$/g and 22 nm, respectively.

$TiO_2$ 첨가에 따른 붕규산 유리의 분상에 관한 연구

박용완,민병욱 한국세라믹학회 1981 한국세라믹학회지 Vol.18 No.4

The tendency of glass containing titanium-dioxide to separate into two phases can be attributed to a change of the coordination number of titanium from six to four on increase of temperature and to "freezing" of the high temperature four fold coordination on cooling of the melt. Addition of TiO2 to the basic glass 8.7 $Na_2O$ 22.4B2O3 68.9 $SiO_2$ was varied 5 to 25 parts. The phase separation in the temperature range of transformation was examined with each heating temperature and soaking time. As the experimental results, the most distinct phase separation were obtained from alkali extraction method when $TiO_2$ was added 15 parts. The apparant activation energy was 30.5 Kcal/mole by alkali extraction method derived from Arrhenius plots.ius plots.