적층형 ZnO바리스터의 내부전극과 Bi$_2$O$_3$ 와의 반응

김영정,김환,홍국선,이종국,Kim, Young-Jung,Kim, Hwan,Hong, Kook-Sun,Lee, Jong-Kook 한국세라믹학회 1998 한국세라믹학회지 Vol.35 No.11

Reactions between Ag-Pd internal electrode materials and{{{{ { {Bi }_{2 }O }_{3 } }} in multilayer chip varistor were in-vestigated. For more than 1 mol%{{{{ { {Bi }_{2 }O }_{3 } }} in varistor composition internal electrode structure was destroyed due to the reaction between internal electrode and{{{{ { {Bi }_{2 }O }_{3 } }} But for typical varistor compositions (below 1 mol% of{{{{ { {Bi }_{2 }O }_{3 } }} content) microstructural changes around the internal electrode were not observed. However SEM-EDS and TEM-EDS analysis showed the uneven distribution of{{{{ { {Bi }_{2 }O }_{3 } }} in the internal electrode which was due to the migration of{{{{ { {Bi }_{2 }O }_{3 } }} to the electorde during sintering. As a results the nonlinear coefficient of multilayer varistor showed very large distribution as well as the breakdown voltage.

단입계 ZnO 단결정 접합체의 바리스터 거동

김영정,김영철,안승준,민준원,Kim, Young-Jung,Kim, Yeong-Cheol,Ahn, Seung-Joon,Min, Joon-Won 한국세라믹학회 2005 한국세라믹학회지 Vol.42 No.5

Single gram-boundary varistors were fabricated using hydrothermal and vapor phase grown ZnO single crystals and their voltage-current relation was studied. The single crystal bonded single junction varistor showed various voltage-current relationship and different breakdown voltage of 0.24-3V. The different types of non-linear current voltage behaviors was attributed to the variation of electrical conductivity in ZnO single crystals.

2차원 ZnO 나노벽 구조 제조

김영정,김영철,안승준,민준원,Kim, Young-Jung,Cao, Guozhong,Kim, Yeong-Cheol,Ahn, Seung-Joon,Min, Joon-Won 한국세라믹학회 2005 한국세라믹학회지 Vol.42 No.7

ZnO 2-D nanowall structure with around 100 nm thickness, which is composed of tens of nm scale ZnO single crystals, was fabricated through the low temperature chemical solution growth method. Electro Chemical Deposition (ECD) technique was applied to attach the ZnO seed crystals on ITO coated glass substrate. The ZnO nanowall structure was grown in the 0.015 mol$\%$ of aqueous solution of zinc nitrate and hexamethenamine at 60$^{\circ}C$ for 20 - 40 h. The nanowall structure depends on the ECD condition or the applied voltage and duration time. The nanowall shows a photoluminescence around 550 - 700 nm spectrum range.

ZrO$_2$와 NiTi 합금의 고상접합 : (I)접합의 최적조건 및 접합강도

김영정,김환,Kim, Young-Jung,Kim, Hwan 한국세라믹학회 1991 한국세라믹학회지 Vol.28 No.8

Stabilized Zirconia (3 mol % Yttria, 3Y-TZP) was joined with intermetallic compound NiTi which has similar thermal expansion coefficient. The optimum bonding condition was determined by the Taguchi Method. Under the optimum bonding condition, the 4-point bending strength was as high as 400 MPa. bonding interfaces were examined by optical microscope, SEM, and TEM; reaction products were identified by XRD and TEM, The relationship between products and strength was examined.

ZnO 세라믹스 거대입성장

김영정,Kim, Young Jung 한국결정성장학회 2019 韓國結晶成長學會誌 Vol.29 No.6

In the process of ZnO ceramic sintering at a temperature of 1385℃, higher than the normal sintering temperature, some grains were growth up to mm scale. When sintered at 1400℃ for 8 hours, the size of the grains that are not involved in the abnormal growth is as large as 30~40 ㎛, but the size of the abnormal grown grain reaches 1,000 ㎛, which is more than 10,000 times bigger in volume than the normal one within 8 hr growth. As a cause of rapid and abnormal grain growth, primary particle size distribution, compaction density variation within sample and doping of impurities could be considered. The primary particle size distribution could be considered main reason for abnormal grain growth but no solid evidence was obtained. Through the observation of the microstructure, it is presumed that the giant grains grow absorbing the neighbor grains through a grain rotation process. ZnO를 통상적인 소결온도 이상의 온도 1385℃에서 소결하는 과정에서 mm 크기로 거대 성장된 입자를 갖는 세라믹스를 제조하였다. 1400℃에서 8시간 소결하는 경우 성장에 참여하지 않은 입자의 크기는 30~40 ㎛이고 거대 성장된 입자는 1,000 ㎛에 달하여 부피비 최소 10,000배 이상의 급속한 성장이 이루어졌다. 이러한 급속한 성장의 원인으로 일차 입자 크기분포, 성형압 불균일 또는 불순물의 합입등을 고려하였으며, 이들 중 일차입자 크기 분포일 것으로 추정되나 확실한 증거를 확보하지 못하였다. 미세구조 관찰을 통해 거대입자 성장은 주변의 입자를 통째로 합치는 과정을 통해 성장하는 것으로 추정된다.

La_xSr_yMn_zO₃ 나노로드 성장 및 특성 분석

김영정,Kim, Young Jung 한국결정성장학회 2016 韓國結晶成長學會誌 Vol.26 No.2

The lanthanum oxide nano-rods were grown on the surface of 3 mol% Yttria Partially Stabilized Zirconia ceramic composite which containing Lanthanum-Strontium Manganate, $La_xSr_yMn_zO_3$ for the purpose of endorsing the antistatic property. The diameter and the aspect ratio of the nano-rods were greatly changed according to the growing condition. With the optical microscope observation, the nano-rods shining brightly. It was confirmed that the major components of nano-rods is La, and Sr, Mn, Si are minor components by SEM and TEM analyses. 기계적 강도가 우수한 부분안정화 지르코니아(3 mol% Yttria Partially Stabilized Zirconia) 세라믹스의 정전기 방지를 목적으로 LSM 복합 세라믹을 제조하는 과정에서 소결체 표면에서 란타늄산화물을 주조성으로 하는 나노로드의 성장을 확인하였다. 성장조건에 따라 나노로드의 직경 및 종횡비가 크게 변화하였으며, 광학현미경으로 관찰한 결과 입사광의 집속현상으로 밝게 빛나는 나노로드를 확인하였다. SEM 및 TEM으로 관찰한 결과, La를 주성분으로 하며 Sr, Mn 그리고 Si 등이 미량 첨가된 산화물임을 확인하였고, 이들의 외형으로부터 결정상이 잘 발달된 것을 확인하였다.

$ZrO_2$와 NiTi 합금의 반응접합 : 분석투과전자현미경을 이용한 $ZrO_2/NiTi$ 접합층 반응생성물 분석

김영정,김환,Kim, Young-Jung,Kim, Hwan 한국세라믹학회 1993 한국세라믹학회지 Vol.30 No.11

Microstructural development at the ZrO2/NiTi bonding interface and reaction products were examined and identified with SEM and AEM. Ti-oxide, Ti2Ni and Ni2Ti layer were observed whose thickness depends on bonding temperature typically. The development of Ti-oxide layer is related with oxygen ion in ZrO2 and liquid phase Ti2Ni. It is considered that compositional deviation from homogeneity and residual stress caused by thermal expansion mismatch are closely related with the formation of the Ti2Ni phase.

존재예화규칙, 존재양화사제거규칙, 다도논법

김영정(Kim, Young-Jung) 서울대학교 철학사상연구소 2009 철학사상 Vol.32 No.-

이 논문은 자연연역체계에서 양화사와 관련된 추론규칙으로 널리 받아들여지고 있는 존재예화규칙 내지 존재양화사제거규칙을 개념적으로 명료화하고자 하는 논문이다. 그 핵심적인 논점은 크게 다음과 같은 네 가지로 요약될 수 있다. 첫째, 일상적으로 같은 것으로 동일시되고 있는 존재예화규칙과 존재양화사제거규칙은 구분되어야 한다. 둘째, 존재양화사제거규칙의 논리적 심층구조는 양도논법을 확장한 다도논법이다. 셋째, 존재예화규칙의 논리적 심층 구조는 다도논법이 아니다. 존재예화규칙의 본성에 대한 설명을 위해서는 반드시 매개변항 개념을 도입해야 한다. 그러나 기존의 논리 체계는 실질적으로 대부분 개체상항, 자유변항, 속박변항 개념만을 사용하고 있으므로, 기존 논리 체계에서는 존재예화규칙의 논리적 심층 구조를 보여줄 길이 없다. 넷째, 그러므로 다음의 두 선택지가 귀결된다. (1) 기존의 논리체계를 받아들이면서 흔히 ‘존재예화규칙’이라고 잘못 불리고 있는 규칙을 존재양화사제거규칙으로 올바르게 이해하던지, (2) 아니면 매개변항 개념을 도입한 새로운 논리 체계를 발전시킴으로써 존재예화규칙을 올바르게 형식화해야 한다. In this paper I have tried to clarify conceptually an inference rule called either the ‘existential specification rule’ or ‘existential-quantifier (∃) elimination rule’, which is broadly accepted as one of the inference rules related to the quantifiers in the natural deduction system. The key issues of this paper can be summarized as the following four points. First of all, the existential specification rule and the existential-quantifier elimination rule, which are usually regarded as one same rule, should be distinguished. Secondly, the deep logical structure of the existential-quantifier elimination rule is polylemma, which is an extension of dilemma. Thirdly, the deep logical structure of the existential specification rule is not polylemma. It is necessary to introduce the concept of parameter for the account of the true nature of the existential specification rule. Since almost all the existing logical systems, however, use only individual constants, free variables and bound variables, it seems impossible to show the deep logical structure of the existential specification rule in those existing logical systems. Therefore, fourthly, only the following two options are left to us: either (1) to admit that the so-called ‘existential specification rule’ is in its true nature the existential elimination rule, maintaining the present logical systems, or (2) to develop a new logical system which includes the concept of parameter, so that we may obtain a correct formulation of the existential specification rule.

논리학과 비판적 사고

김영정(Young-Jung Kim) 대한토목학회 2005 대한토목학회지 Vol.53 No.9

인지과학과 가족 유사성

김영정(Young Jung Kim) 철학연구회 1994 哲學硏究 Vol.34 No.-