xB₂O₃ -yBi₂O₃-zPbO-5SiO₂계 유리의 전기적인 특성

정맹식,주경복,이남한,Joung, Maeng Sig,Ju, Kyung Bok,Lee, Nam Han 한국안광학회 2001 한국안광학회지 Vol.6 No.1

BB-계열에서 $Bi_2O_3$ 함량이 증가할수록 비저항의 peak는 낮은 온도로 이동하였다. 비저항에 대한 완화현상을 설명하기 위한 등가회로는 G-C의 병열회로이고, 전기전도과정은 체적전도이며, 완화의 형태는 non-Debye 형이었다. 그리고 BB-계열의 전기전도 현상은 일반적으로 s가 거의 일정한 (s=0.8) QMT 모델에 잘 맞는 것으로 판명되었다. The temperature dependence of dielectric constant and electrical conductivity for the BBPS glasses system was studied over a temperature range between $30^{\circ}C$ and $500^{\circ}C$ and at a frequency ranged from $10^3$ Hz to $10^7$ Hz. The dielectric constant ${\varepsilon}$ at room temperature of $xB_2O_3-yBi_2O_3-zPbO-5SiO_2 $ glasses was measured to be 15 at $10^5$ Hz for all samples and found to be almost frequency independent. At the relatively low temperature ranger (<$70^{\circ}C$), the dielectric constant was almost temperature independent and above that it increased with increasing temperature: the rate of increase being different at different frequencies. This behavior could be explained on the basis of the presence of molecular dipoles. The dielectric constant was found to depend on the composition as well as the crystalline phases formed in the glass matrix.

열전도 측정에 의한 Pb₅Ge₃O₁₁ 단결정의 상전이

정맹식,Joung, Maeng-Sig 한국안광학회 1999 한국안광학회지 Vol.4 No.2

시료의 한 부분에 순간적으로 가열하여 시료의 특정 부분의 온도변화를 조사함으로써 시료의 열 확산도를 측정하였다. $Pb_5Ge_3O_{11}$ 단결정의 환산 열 확산도는 trigonal 구조인 $30^{\circ}C$에서는 $0.0117cm^2/^{\circ}C$, curie point 근방인 $178^{\circ}C$에서는 $0.0105cm^2/^{\circ}C$이며 hexagonal 구조인 $180^{\circ}C$에서는 0.0112cm로 각각 나타났다. 이는 $Pb_5Ge_3O_{11}$ 단결정을 같은 열량으로 가열하였을 때, 실온에서 curie 온도쪽으로 갈 때 가열 효과가 적었으며 curie point에서 최소가 되었다가 curie 온도 이상에서는 갑자기 증가하여 일정하게 되었다. 따라서 $Pb_5Ge_3O_{11}$ 단결정의 상전이 용도가 1m 근방임을 확인하였다. The thermal diffusivity of lead germanate single crystal was measured from room temperture up to the $200^{\circ}C$ by heating method. The thermal diffusivities were measured as k=0.0117, 0.0105, and $0.0112cm^2/^{\circ}C$ at $30^{\circ}C$, $177^{\circ}C$, and $180^{\circ}C$, respectively. It is identified that the heat capacity of the lead germanate single crystal is maximum at $177^{\circ}C$, and this point is phase transition temperature of $Pb_5Ge_3O_{11}$ single crystal.

B₂O₃-Bi₂O₃-PbO-SiO₂계 유리의 광학적인 특성

정맹식,김홍선,이수대,Joung, Maeng Sig,Kim, Hong Seon,Lee, Su Dae 한국안광학회 2000 한국안광학회지 Vol.5 No.2

시편의 열분석과 SEM 분석에서 투명한 BP-계열의 시료 중 BP-1은 두 가지의 미세한 상으로 형성된 액적을 가진 유리 상을 발견할 수 있었고 열처리에 의하여 불혼화 영역이 생겨났다. BP-2 시료의 경우에서는 구형의 불혼화 영역이 관찰되는데 이와 같은 불혼화 현상의 원인은 용융액 내에 존재하는 양이온의 이온장 세기에 의한 것으로 해석하였다. 그리고 BP-계열 유리의 파장에 대한 흡수도는 $Bi_2O_3$의 함량이 많을수록 크게 나타났으며 400~800 nm 파장범위에서 흡수도의 변화는 완만하게 나타났다. 그리고 자외선에 대한 흡수단은 좀더 긴 파장 쪽으로 이동하였다. FT-IR 스펙트럼에서 BP-계열의 유리는 PbO 함량이 많은 시료가 보다 큰 흡수가 일어났으며 $3382cm^{-1}$과 $2800cm^{-1}$에서 나타나는 흡수대는 각각 사면체 $BO_1$에서 B-O 신축진동에 해당하는 흡수대와 B-O-B 변각진동에 해당하는 흡수대임을 알 수 있었다. BP-계열에서 $3400cm^{-1}$ 흡수대들이 예리해지는 것은 유리질 내 생성된 결정상이 성장하고 있는 것으로 판명되었다. Four glasses of $B_2O_3-Bi_2O_3-PbO-SiO_2$ (BBPS) system were prepared by melting the appropriate amounts of reagent grade oxides of $B_2O_3$, $Bi_2O_3$, PbO, and $SiO_2$ in an open crucible. The differential thermal analysis showed crystallization temperature decreased with increasing $Bi_2O_3$ or PbO content in the sample. The structures of glasses system were studied using scanning electron microscopy and Fourier transform-Infra red (FT-IR) spectroscopy. The UV cut-off and refractive index were found to be sensitive to the $Pb^{+2}$ and $Bi^{+3}$ content in the glasses. The behavior of the IR spectra of the glasses in the BP series was consistent with a role of $Bi_2O_3$ as a network former. In the BP series of glasses, the result of IR spectrum indicated that PbO behaved as a network former.

B<SUB>2</SUB>O<SUB>3</SUB>를 함유한 Bi<SUB>2</SUB>O<SUB>3</SUB>-PbO-SiO<SUB>2</SUB> 계 유리의 유전적 특성

정맹식(Maeng-Sig Joung),이수대(Su-Dae Lee) 한국안광학회 2001 한국안광학회지 Vol.6 No.2

열전도 측정에 의한 Pb<SUB>5</SUB>Ge₃O<SUB>11</SUB> 단결정의 상전이

정맹식(Maeng Sig Joung) 한국안광학회 1999 한국안광학회지 Vol.4 No.2

The thermal diffusivity of lead germanate single crystal was measured from room temperture up to the 200℃ by heating method. The thermal diffusivities were measured as k=0.0117, 0.0105, and 0.0112 ㎠/ at 30℃, 177℃, and 180℃, respectively. It is identified that the heat capacity of the lead germanate single crystal is maximum at 177℃, and this point is phase transition temperature of Pb_5Ge₃,O_(11) single crystal.

xB₂O₃ - yBi₂O₃ - zPbO - 5SiO₂ 계 유리의 전기적인 특성

정맹식(Maeng Sig Joung),주경복(Kyung Bok Ju),이남한(Nam Han Lee) 한국안광학회 2001 한국안광학회지 Vol.6 No.1

The temperature dependence of dielectric constant and electrical conductivity for the BBPS glasses system was studied over a temperature range between 30℃ and 500℃ and at a frequency ranged from 10³ Hz to 10^7 Hz. The dielectric constant ε at room temperature of xB₂O₃-YBi₂O₃-zPbO-5SiO₂ glasses was measured to be 15 at 10^5 Hz for all samples and found to be almost frequency independent. At the relatively low temperature range($lt;70℃), the dielectric constant was almost temperature independent and above that it increased with increasing temperature. the rate of increase being different at different frequencies. This behavior could be explained on the basis of the presence of molecular dipoles. The dielectric constant was found to depend on the composition as well as the crystalline phases formed in the glass matrix.

B₂O₃ - Bi₂O₃ - PbO - SiO₂ 계 유리의 광학적인 특성

정맹식(Maeng Sig Joung),김홍선(Hong Seon Kim),이수대(Su Dae Lee) 한국안광학회 2000 한국안광학회지 Vol.5 No.2

Four glasses of B₂O₃ - Bi₂O₃ - PbO - SiO₂ ( BBPS) system were prepared by melting the appropriate amounts of reagent grade oxides of B₂O₃, Bi₂O₃. PbO, and SiO₂ in an open crucible. The differential thermal analysis showed crystallization temperature decreased with increasing BizO₃ or PbO content in the sample. The structures of glasses system were studied using scanning electron microscopy and Fourier transform - Infra red ( FT - IR ) spectroscopy. The U V cut - off and refractive index were found to be sensitive to the Pb^(+2) and Bi^(+3) content in the glasses. The behavior of the IR spectra of the glasses in the BP series was consistent with a role of Bi₂O₃ as a network former. In the BP series of glasses, the result of IR spectrum indicated that PbO behaved as a network former.

보색을 이용한 눈의 굴절력 측정

정맹식(Maeng Sig Joung) 한국안광학회 2002 한국안광학회지 Vol.7 No.2

시력 보정용 렌즈의 품질 개선방향

정맹식(Maeng Sig Joung),김홍선(Hong Seon Kim) 한국안광학회 1998 한국안광학회지 Vol.3 No.1

Todays in the field of lens makers, the technology machinery equipment and investment is shrunken by many factors. But much more decisive investment is wanted to strengthen competitiveness. Most of all, the technology of management and quality examination is important in the confidence of lens. So external and internal examination must be accomplished scientifically not by macrography but by the microscope and the computer. As the hardness examination of glass in the automobile, that of spectacle lens must not be harmful to the human body. All the raw material of spectacle lens is being imported for the lack of technology. To overcome these circumstances, We must establish the research institute that can develop the technology and must train a technical expert.

Synthesis and Properties of Poly(ether-b-ester)Thermoplastic Elastomers

김홍선,정맹식,Kim, Hong Seon,Joung, Maeng Sig 한국안광학회 2001 한국안광학회지 Vol.6 No.1

Dimethyl terephthalate (DMT). 1.4-butanediol (1.4-BD) and poly (tetramethylene ether) glycol (PTMG) in the molecular weight of 2000 (g/mol) were used to synthesize poly(ether-b-ester) thermoplastic elastomers (TPEEs). The final copolymers were annealed to improve thermal stability at elevated temperatures and mechanical properties. This study showed that as the proportion of soft segment increases melting temperature and degree of crystallinity of TPEEs decrease constantly. In case of mechanical properties like flexural strength and flexural elastic modulus. $35-PTMG^{2000}$ indicates the highest values due to more efficient physical interlock. 디메틸 테레프탈레이트 (DMT), 1.4-부탄디올 (1.4-BD) 그리고 분자량이 2000인 폴리테트라 메틸렌 에테르 글리콜 (PTMG)로 부터 폴리에스터계 열가소성 탄성체 (TPEE)를 합성할 수 있었다. 열적 안정성 및 기계적 물성을 증대시킬 목적으로 열처리를 하였으며, 이에 따라 결정성 hard segmen의 보다 규칙적인 배열로 인한 향상된 물성을 확인 할 수 있었다. 본 실험에서 합성된 공중합체는 soft segment의 함량이 증가함에 따라 융점 및 결정화도가 감소함을 보여 주었다. 기계적 물성의 경우, soft segment의 함량이 35%인 공중합체가 soft segment와 hard segment간 최적의 물리적 가교점 형성으로 인하여 가장 우수함이 관찰되었다.