Phosphors for Plasma Display Panels

김창홍,배현숙,변종홍,홍광옌,Kim, Chang Hong,Bae, Hyun Sook,Pyun, Chong Hong,Hong, Guang Yan Korean Chemical Society 1998 대한화학회지 Vol.42 No.5

플라스마 표시판용으로 사용되거나 제안 또는 알려진 형광체들의 들뜸 및 발광 특성을 살펴 보았다. 각 형광체의 발광 효율이 임자 결정과 활성제의 종류에 따라 어떻게 달라지는지 알아 보았고 실용성 있는 형광체의 개발 방향을 생각하였다. Excitation and emission characteristics were reviewed for phosphors which were reported, applied, or suggested for the plasma display panel (PDP). Correlation of luminescence characteristics to the host crystal structure and the activator of the phosphor was explained. Improvements of the PDP phosphor for the practicality were considered.

Molecular Theory of Plastic Deformation (II). Applications

김창홍,이태규,Kim, Chang Hong,Ree Taikyue Korean Chemical Society 1977 대한화학회지 Vol.21 No.5

소성변형에 대한 저자들의 이론(제1보)을 요업재료, 금속, 합금 및 단결정들에 적용하였다. 그 결과 다중 결정에서는 dislocation 운동과 grain boundary 운동이 실험조건에 따라 함께 또는 분리되어 나타나는 반면 단결정에서는 dislocation 운동만 나타났다. 유동식에 나타나는 파라미터$({\alpha}_{d1},\;1/{\beta}_{d1})와\;({\alpha}_{gj}/X_{gj},\;1/{\beta}_{gj})$ (j = 1 or 2) 및 활성화엔탈피 ${\Delta}H_{k1}^{\neq}$ (k = d 혹은 g)를 구하여 예측한 소성변형은 실험과 잘 일치함을 보았다. 여기서 첨자 d1는 첫번째의 dislocation 유동단위, gj는 j번째 grain boundary 유동단위를 나타낸다. 활성화엔탈피에 대하여 ${\Delta}H_{d1}^{\neq}$는 bulk의 자체확산에 대한 활성화엔탈피와 일치하고 ${\Delta}H_{g1}^{\neq}$는 grain boundary 자체확산에 대한 활성화엔탈피와 일치하였다. 이 사실은 저자들의 이론의 정당성을 보이고 있다. The authors' theory developed in the preceding Paper 1 was applied to plastic deformation of ceramics, metals, alloys and single crystals. For polycrystalline substances, the flow mechanisms due to dislocation movement and grain boundary movement appear together or separately according to the experimental conditions whereas for single crystals, only the mechanism of dislocation movement appears. The parameters appearing in the flow equations $({\alpha}_{d1},\;1/{\beta}_{d1})and\;({\alpha}_{gj}/X_{gj},\;1/{\beta}_{gj})$ (j = 1 or 2), and the activation enthalpies ${\Delta}H_{k1}^{\neq}$ (k = d or g) were determined and tabulated. Here, the subscript d1 indicates the first kind of dislocation flow units and gj expresses the jth kind of grain boundary flow units. The predictions of the theory were compared with experiment with good agreement. Concerning the activation enthalpies, it was found that ${\Delta}H_{d1}^{\neq}$ 〉{\Delta}H_{g1}^{\neq}$ and that the former agrees with the activation enthalpy for bulk self-diffusion whereas the latter agrees with the activation enthalpy for grain boundary self-diffusion. These facts support the adequacy of the authors' theory which is considered as a generalized theory of plastic deformation.

Molecular Theory of Plastic Deformation (I). Theory

김창홍,이태규,Kim Chang Hong,Ree Taikyue Korean Chemical Society 1977 대한화학회지 Vol.21 No.5

In order to elucidate the plastic deformation of solids, the following assumptions were made: (1) the plastic deformation of solids is classified into two main types, the one which is caused by dislocation movement and the other caused by grain boundary movement, each movement being restricted on a different shear surface, (2) the dislocation movement is expressed by a mechanical model of a parallel connection of various kinds of Maxwell dislocation flow units whereas the grain boundary movement is also expressed by a parallel connection of various kinds of Maxwell grain boundary flow units; the parallel connection in each type of movements indicates that all the flow units on each shear surface flow with the same shear rate, (3) the latter model for grain boundary movement is connected in series to the former for dislocation movement, this means physically that the applied stress distributes homogeneously in the flow system while the total strain rate distributes heterogeneously on the two types of shear planes (dislocation or grain boundary shear plane), (4) the movement of dislocation flow units and grain boundary units becomes possible when the atoms or molecules near the obstacles, which hinder the movement of flow units, diffuse away from the obstacles.Using the above assumptions in conjunction with the theory of rate processes, generalized equations of shear stress and shear rate for plastic deformation were derived. In this paper, four cases important in practice were considered.ted N${\cdot}{\cdot}{\cdot}$O hydrogen bond and the second of two normal N${\cdot}{\cdot}{\cdot}$O hydrogen bonds, both of which exist between the amino group and the perchlorate, groups. A p-phenylenediamine group is approximately planar within an experimental error and bonded to twelve perchlorates: ten perchlorates forming hydrogen bonds and two being contacted with the van der Waals forces. A perchlorate group is surrounded by six p-phenylenediamines and four perchlorates; among the six p-phenylenediamines, five of them are hydrogen-bonded, and the rest contacted with the van der Waals force. 고체의 소성변형을 설명하기 위하여 다음과 같은 가정을 하였다. (1) 고체의 소성변형은 크게 두 가지 기구 즉 dislocation 운동과 grain boundary 운동에 의하여 일어난다. (2) Dislocation 운동에 있어서 유동 단위들은 역학적 모형으로 나타내면 다종의 Maxwell 단위들의 평행연결형으로 되고 grain boundary 유동단위들도 다종의 Maxwell 단위들의 평행연결로 표현된다. 이를 물리적으로 설명하면 같은 부류의 유동단위들은 모두 같은 shear plane에서 같은 shear rate로 흐름을 의미한다. (3) Grain boundary 유동단위들과 dislocation 유동단위들 같은 서로 직렬 연결되어 있다. 이는 물리적으로 고체내에서 stress는 균일하게 작용하나 shear rate는 shear plane 의 종류(dislocation 운동면과 grain boundary 운동면)에 따라 달리 나타남을 의미한다. (4) Dislocation 유동단위들과 grain boundary 운동단위들의 운동은 그들의 흐름을 방해하는 장애물 근방의 원자 또는 분자들이 확산해 나가므로써 가능하게 된다. 이러한 가정하에 반응속도론을 적용하여 shear rate와 shear stress를 구하는 일반식을 도출하였다. 본 연구에서는 실제로 중요한 네가지 경우에 대하여 상기 도출한 일반식을 고찰하였다.

Molecular Theory of Superplastic Deformation

김창홍,이태규,Chang Hong Kim,Taikyue Lee Korean Chemical Society 1979 대한화학회지 Vol.23 No.4

소성변형에 대한 著者들의 이론을 초소성합금(Zn-Al eutectoid, A1-Cu, Pb-Sn, Sn-Bi, Mg-Al eutectics)에 적용하였다. 그 결과 초소성합금의 소성변형은 두 개의 grain boundary流動單位의 平行連結로 나타낼 수 있었다. 이 두 개의 流動單位는 流動式에 나타나는 parameter $X_{gj}/{\alpha}_{gj}$와 ${\beta}_{gj}$(j=1 혹온 2)로 表現할 수 있으며 이들을 實驗的으로 求할 수 있었다. 著者들의 流動式은 實驗과 잘 一致하였다. Strain rate sensitivity 對 -In(strain rate) 곡선을 이론으로 구한 결과 유동단위수만큼의 peak가 ${\beta}_{gj}$(j=1 or 2) 값에 따라 분리되어 나타났고 초소성의 조건도 ${beta}_{gj}$값에 의하여 결정됨을 알았다. ${\beta}_{gj}값의 粒子크기 依存性을 구하였고 온도변화에 따른 ${\beta}_{gj}$값 변화로부터 각 流動單位의 활성화엔탈피, ${\Delta}H_{gj}^{\neq}$도 구하였다. 그 결과 ${\Delta}H_{gj}^{\neq}$는 재료성분원소들의 grain boundary 자체확산에 의한 활성화엔탈피와 같이 나타났고 또 이들은 粒子 크기 증가에 마라 증가함을 보였다 The author's theory for plastic deformation was applied to superplastic alloys (Zn-Al eutectoid, Al-Cu, Pb-Sn, Sn-Bi, Mg-Al eutectics). The plastic deformation of the superplastic alloys could be described by two Maxwell models connected in parallel which represent two grain boundary flow units. The flow units are characterized by the two parameters $X_{gj}/{\alpha}_{gj}\;and\;{\beta}_{gj}$ (j=l or 2, g signifies the grain boundary) the values of which were obtained by applying our flow equation [Eq. (5)] to experiment. We confirmed that our flow equation describes the superplasticity very well. The curve of strain rate sensitivity m (=${\partial}\;In\;f/{\partial}\;In\;\dot{s})\;vs.\;-In\dot{s}$, where f and s are stress and strain rate, respectively, showed two peaks corresponding to flow unit gl and g2, the separation of the two peaks is determined by the difference between ${\beta}_{g1}\;and\;{\beta}_{g2}$. The condition of superplasticity is also determined by ${\beta}_{gj}$, which satisfies $\dot{s}_{mj}{\leqslant}1.53}{\beta}_{gj}$ [Eq.(13)], where $\dot{s}_{mj}$ is the s of the jth unit at the peak. The grain size dependence of ${\beta}_{gj}$ is described by $ln({\beta}_{gj})^{-1}$=alnx+b [Eq. (16)], where x is the grain size, and a and b are constants. The activation enthalpy for each flow unit, ${\Delta}H_{gj}^{\neq}$ was also determined from the temperature dependence of ${\beta}_{gj}$ which is proportional to the relaxation time of the j th unit. Since the superplasticity is determined by Eq. (13), and since ${\beta}_{gj}$ and ${\Delta}H_{gj}^{\neq}$ are related, we obtained the conclusion that superplasticity occurs in the system having small ${\Delta}H_{gj}^{\neq}$ values. The Aej values were equal to the activation enthalpies of grain boundary self-diffusion of the component atoms of the alloys, this accords with our proposed flow mechanism. The ${\Delta}H_{gj}^{\neq}$ value increases with grain size as expected from Eq. (16).

Complex Formation Between Ferric Ion and Phosphoric Acid

김명순,손연수,김창홍,Kim Myeong Soon,Youn Soo Sohn,Chang Hong Kim Korean Chemical Society 1975 대한화학회지 Vol.19 No.5

Complex formation between ferric ion and phosphoric acid has been studied in the wide range of the acid concentration(0${\sim}40{\%}$) by uv-visible spectroscopy and by characterization of the isolated products. The electronic spectra of Fe(III)-containing phosphoric acid solutions exhibit two visible bands at 19.2 and 24.1 kK, which are characteristic of Fe(III)-phosphate complex formation. The measurements of acid concentration dependence of the opical density of the 24.1 kK band indicates the presence of two distinct forms of Fe(Ⅲ)-phosphate complexes possibly $[Fe(H_xPO_4)]^{x+}\;and\;[Fe_2 (H_xPO_4)]^{(3+x)+}$. The 1:1 complex has been isolated for characterization, and the phosphate ion was found to be coordinated to the metal in monobasic state whereas the isolation of the dimeric species was unsuccessful. 철(III) 이온과 인산간의 착물형성에 관하여 넓은 인산산성범위(0${\sim}40{\%}$)에서 가시부스펙트럼과 용액으로 부터 분리해낸 화합물을 검토함으로써 연구하였다. 철(III)함유 인산용액의 전자흡수 스펙트럼은 19.2kK 및 24.1kK에서 철(III)-인산 착물형성을 나타내는 두개의 가시부 흡수를 나타내었다. 24.1kK 밴드의 인산농도에 따른 흡광도 변화의 측정으로부터 아마도 $[Fe(H_xPO_4)]^{x+}\;및\;[Fe_2 (H_xPO_4)]^{(3+x)+}$등 두개의 형태가 틀린 철(III)-인산착물이 존재함을 알 수 있었다. 이들 두화합물중 몰비가 1:1인 착물은 고체상태로 분리하는데 성공하였으며 인산이온은 염기도 1인 상태로 금속에 배위되어 있음을 알 수 있으나, 이합체로 생각되는 화합물은 분리해낼 수 없었다.

소화용 마이크로캡슐을 함유한 소화 벽지의 개발

이상섭(Sang-Sub Lee),김창홍(Chang-Hong Kim),김민철(Min-Chul Kim),김종상(Jong-Sang Kim) 한국화재소방학회 2020 한국화재소방학회논문지 Vol.34 No.6

최근의 화재 사건들을 보면 노래방, 고시원 같은 좁고 밀폐된 공간에서의 화재만이 아니라 목욕탕, 물류창고 등넓은 공간에서의 화재가 발생하며, 특히 좁은 공간에서의 화재는 벽지를 통해 급격한 화재 확산과 그로 인해 발생하는 대량의 유독가스로 인해 골든타임이 단축되고, 현장에서 대피하지 못해 많은 인명피해가 일어나고 있다. 이에 대한 대책으로 불에 잘 타지 않는 방염성을 부여한 다양한 벽지가 개발되고 있지만, 방염 성분이 일반 벽지보다 5배이상의 CO를 배출해 더 심각한 인명피해를 초래할 수 있다. 본 연구에서는 불길 확산의 주원인인 벽지에 소화 성능을 함유시켜 화재 발생 시 대피 시간 증가 및 불길 확산 억제의 효과를 기대하는 소화 벽지를 개발했다. 일반 물풀에소화용 마이크로 소화 캡슐을 함유해 일반 벽지의 전소 시간을 2 min에서 5 min으로 증가함을 확인했으며, 벽지 뒷면에 마이크로 소화 캡슐을 점착제 형태로 부착 후 전소 Test 및 45° 난연 시험에서 소화 유효성을 확인했으며, 열중량 분석(TGA)를 통해 반응 시작온도, Peak point, 반응 종료 온도 및 중량감소율을 확인하여 접착성 필름의 열적 특성을 확인하였으며, 시중의 방염 벽지와의 연기밀도를 비교해 유의한 결과를 얻을 수 있었다. In this study, a wallpaper with fire-extinguishing properties was developed. This wallpaper is expected to increase theevacuation time and suppress the spread of flames in case of fire. It was confirmed that the fire-extinguishing time of anordinary wallpaper can be increased from 2 to 5 min by incorporating micro-extinguishing capsules in the general waterpool. After attaching microfire-extinguishing capsules in the form of a film on the back of the wallpaper, a burning testusing a torch and 45° flame retardant digestion was performed, and the thermal properties of the adhesive film were verifiedbased on the reaction start temperature, peak point, reaction end temperature, and weight reduction rate throughthermogravimetric analysis.

정상 임신과 임신성 고혈압 환자에서의 혈장 Fibronectin 농도에 관한 연구

홍기연 ( Gi Youn Hong ),박성찬 ( Sung Chan Park ),김창홍 ( Chang Hong Kim ),이희섭 ( Hee Sub Rhee ),민부기 ( Bu Kie Min ),김기석 ( Kie Suk Kim ) 대한주산의학회 1992 大韓周産醫學會雜誌 Vol.3 No.2

X-선 회절법에 의한 Y₂O₃-Y₂O₂S 이성분계 혼합물의 정량분석

김영만(Young Man Kim),정찬이(Chan Yee Jeong),김창홍(Chang Hong Kim),이종욱(Chong Wook Lee) 한국분석과학회 1989 분석과학 Vol.2 No.2

MTF 기반 열적외선 카메라의 해상력 성능평가 방법 개발

손준우(Sohn Joon Woo),김희강(Kim Hee Kang),김창홍(Kim Chang Hong),김지연(Kim Ji Yeon),조태식(Cho Tae Sik),박길흠(Park Kil Houm) 한국통신학회 2021 한국통신학회 학술대회논문집 Vol.2021 No.6

기존의 열적외선 카메라의 해상력 평가는 최소 분해 가능 온도차(MRTD) 측정 방법으로 해상력을 측정하였다. 하지만, 기존 방법의 해상력 측정 방법은 평가자의 주관적인 요소가 포함되어 있어 재현성이 부족하며, 객관적이지 않은 문제가 있다. 본 연구에서는 객관적이며, 정량적으로 열적외선 카메라의 해상력을 측정하기 위해 흑체로와 Slanted-Edge target을 이용하여 MTF기반의 해상력 측정방법을 사용하여 열적외선 카메라의 해상력 평가 방법을 제안한다.

자궁근종의 임상 및 병리학적 연구

황성연,홍성진,김창홍,김흥곤 圓光大學校 醫科學硏究所 1997 圓光醫科學 Vol.13 No.1-2

Uterine myoma is the most common solid pelvic tumor in women. Nevertheless, etiology and symptomatology remain poorly understood, and management is inconsistent. In an effort to improve understanding of these aspects of uterine myoma, we have reviewed and analysed the data results obtained from myoma patients at department of obstetrics and gynecology, Wonkwang university hospital during the years 1995 to 1996. The following results have been obtained. 1. During the period the incidence of uterine myoma among 1,116 cases of major gynecologic surgery was 27.2 %. 2. Myoma was observed most frequently in the age group 40 to 49 years and the mean age was 43.6 years. 3. The intramural type was observed in 200 cases (65.8 %), mixed type in 53 cases (17.4 %), subserous type in 29 cases (9.5 %) and submucous type in 22 cases (7.3 %) respectively. 4. The symptoms commonly found in decreasing order were abnormal uterine bleeding (57.3 %), pain or pressure symptoms (53.3 %) and palpable mass (22.4 %). 5. Hypermenorrhea was observed in 96 cases (31.6 %) and there were significant correlations between the presence of hypermenorrhea and the type of myoma, associated adenomyosis. ( p< 0.05 ) 6. There were no significant correlations between the dysmenorrhea and the type of myoma, associated adenomyosis. ( p > 0.05 ) 7. Abnormal electrocardiographic findings were noticed in 18.8 %. 8. Mean hemoglobin level were 10.2 gm/㎗ and less than 10 gm/㎗ was found in 26.6 % and transfusion was performed in 20.8 %. 9. The most frequently associated disease in uterine myoma was adenomyosis seen in 43.4 %. 10. The secondary pathologic changes in uterine myoma were found in 5.0 % and the most common change was hyaline degeneration (3.0 %). 11. The infertility was observed in 10.2 % in which the primary infertility was 6.3 % and secondary 3.9 % respectively. 12. Total abdominal hysterectomy was performed in 84.2 % and vaginal hysterectomy in 11.8 %, myomectomy in 3.3 % respectively. 13. The postoperative complications were found in 26.6 % and the most common complication was the fever (13.8 %).