시뮬레이션을 활용한 폰카메라 렌즈모듈 부품용 사출금형개발

김혜정,김재훈,김영규,송준엽,문덕희,Kim, Hye Jeong,Kim, Jae Hoon,Kim, Yeong Gyoo,Song, Jun Yeob,Moon, Dug Hee 한국시뮬레이션학회 2013 한국시뮬레이션학회 논문지 Vol.22 No.4

휴대폰 시장의 확산으로 인하여 휴대폰에 장착되는 카메라 렌즈모듈의 수요도 급증하고 있다. 렌즈모듈 부품의 경우 해상도의 증가에 따른 사출공정의 품질보증과 원가절감이라는 두 가지 목표를 달성해야 한다. 따라서 본 논문에서는 더블카세트 방식의 금형구조를 이용하여 경통과 쉴드 두 종류의 제품을 개발하기 위해 시뮬레이션을 활용한 사례를 소개한다. 개발과정에서 두 종류의 시뮬레이션 기술을 활용하였는데, 첫 번째는 금형 설계단계에서 사출품의 성형성을 분석하기 위한 시뮬레이션(일명 Computer Aided Engineering)을 Mold Flow$^{TM}$를 사용하여 수행하였고, 두 번째는 사출기에 금형을 장착한 후 제품이 사출되어 취출하는 동작을 분석하기 위한 동작 시뮬레이션을 DPM Assembly$^{TM}$를 이용하여 수행하였다. 개발 결과 기존 방식에 비해 제품의 생산성이 300% 이상 증가하는 효과를 얻었다. The demand of a camera-lens-module which is installed in mobile phone has been increased explosively as the increase of mobile phone market. Recently, two missions are given to the parts manufacturer of lens module, and they are how to keep the quality of injection moulding process as the increase of resolution, and how to decrease manufacturing cost. In this paper, a simulation study is introduced which is used for developing barrel and shield considering the double-cassette type of mould. At first, the simulation for injection process using Mold Flow$^{TM}$ is applied in the phase of mould design, and mechanical simulation using DPM Assembly$^{TM}$ is applied for collision detection between picking robot and mould. As a result, the productivity increased more than 300%.

탄소층으로 캡슐화된 Ni나노입자 촉매의 CO₂ 메탄화 반응

김혜정,김승보,김동현,윤재랑,김민재,전상구,이경자,이규복,Kim, Hye Jeong,Kim, Seung Bo,Kim, Dong Hyun,Youn, Jae-Rang,Kim, Min-Jae,Jeon, Sang Goo,Lee, Gyoung-Ja,Lee, Kyubock 한국재료학회 2021 한국재료학회지 Vol.31 No.9

Carbon-encapsulated Ni catalysts are synthesized by an electrical explosion of wires (EEW) method and applied for CO₂ methanation. We find that the presence of carbon shell on Ni nanoparticles as catalyst can positively affect CO₂ methanation reaction. Ni@5C that is produced under 5 % CH₄ partial pressure in Ar gas has highest conversions of 68 % at 350 ℃ and 70 % at 400 ℃, which are 73 and 75 % of the thermodynamic equilibrium conversion, respectively. The catalyst of Ni@10C with thicker carbon layer shows much reduced activity. The EEW-produced Ni catalysts with low specific surface area outperform Ni catalysts with high surface area synthesized by solution-based precipitation methods. Our finding in this study shows the possibility of utilizing carbon-encapsulated metal catalysts for heterogeneous catalysis reaction including CO₂ methanation. Furthermore, EEW, which is a highly promising method for massive production of metal nanoparticles, can be applied for various catalysis system, requiring scaled-up synthesis of catalysts.

DOE를 적용한 카메라폰 모듈용 비구면 Glass 렌즈의 가압성형조건 연구

김혜정,차두환,이준기,김상석,김정호,Kim, Hye-Jeong,Cha, Du-Hwan,Lee, Jun-Key,Kim, Sang-Suk,Kim, Jeong-Ho 한국전기전자재료학회 2007 전기전자재료학회논문지 Vol.20 No.8

This study investigated the pressing conditions in the molding of aspheric glass lenses for the mega pixel phone camera module using the DOE method. Tungsten carbide (WC; Japan, Everloy Co., 002K),which contained 0.5 w% cobalt (Co), was used to build the mold. The mold surface was ultra-precision ground and polished, and its form accuracy (PV) was 0.85um in aspheric surface. We selected four factors, pressing temperature, force and time of first step, and force of second step, respectively, as the parameters of the pressing process. in order to reduce the number of experiments, we applied fractional factorial design considering the main effects and two-way interactions. The analysis results indicate that the only two main effects, the pressing temperature and the time of pressing step 1, are available for the form accuracy (PV) of the molded lens. The analysis results indicated that the best combination of the factors for lowering the form accuracy(PV) value of molded lens was to have them at their low levels.

Hot Wall Epitaxy(HWE)법에 의한 MgGa₂Se₄ 단결정 박막 성장과 가전자대 갈라짐에 대한 광전류 연구

김혜정,박향숙,방진주,강종욱,홍광준,Kim, Hyejeong,Park, Hwangseuk,Bang, Jinju,Kang, Jongwuk,Hong, Kwangjoon 한국결정성장학회 2013 韓國結晶成長學會誌 Vol.23 No.6

수평 전기로에서 $MgGa_2Se_4$ 다결정을 합성하여 HWE(Hot Wall Epitaxy)방법으로 $MgGa_2Se_4$ 단결정 박막을 반절연성 GaAs(100)기판에 성장시켰다. $MgGa_2Se_4$단결정 박막의 성장 조건은 증발원의 온도 $610^{\circ}C$, 기판의 온도 $400^{\circ}C$였고 성장 속도는 $0.5{\mu}m/hr$였다. 이때 이중결정 X-선 요동곡선(DCRC)의 반폭치(FWHM)도 212 arcsec로 가장 작아 최적 성장 조건임을 알 수 있었다. $MgGa_2Se_4$/SI(Semi-Insulated) GaAs(100) 단결정 박막의 광흡수와 광전류 spectra를 293 K에서 10 K까지 측정하였다. 광흡수 스펙트럼으로부터 band gap Eg(T)는 varshni공식에 따라 계산한 결과 $E_g(T)=2.34 eV-(8.81{\times}10^{-4}eV/K)T^2/(T+251K)$이었으며 광전류 스펙트럼으로부터 Hamilton matrix(Hopfield quasicubic mode)법으로 계산한 결과 crystal field splitting energy ${\Delta}cr$값이 190.6 meV이며 spin-orbit energy ${\Delta}so$값은 118.8 meV임을 확인하였다. 10 K일 때 광전류 봉우리들은 n = 1, 27일때 $A_{1^-}$, $B_{1^-}$와 $C_{27}-exciton$ 봉우리임을 알았다. A stoichiometric mixture of evaporating materials for $MgGa_2Se_4$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $MgGa_2Se_4$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperatures were $610^{\circ}C$ and $400^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by double crystal X-ray diffraction (DCXD). The temperature dependence of the energy band gap of the $MgGa_2Se_4$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=2.34 eV-(8.81{\times}10^{-4}eV/K)T^2/(T+251K)$. The crystal field and the spin-orbit splitting energies for the valence band of the $MgGa_2Se_4$ have been estimated to be 190.6 meV and 118.8 meV, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the ${\Delta}so$ definitely exists in the ${\Gamma}_5$ states of the valence band of the $MgGa_2Se_4$/GaAs epilayer. The three photocurrent peaks observed at 10 K are ascribed to the $A_{1^-}$, $B_{1^-}$exciton for n = 1 and $C_{27}-exciton$ peaks for n = 27.

굴삭기 부품 용접 자동화라인의 셀생산방식 적용을 위한 시뮬레이션 연구

김혜정,이승우,문덕희,Kim, Hye Jeong,Lee, Seung Woo,Moon, Dug Hee 한국시뮬레이션학회 2013 한국시뮬레이션학회 논문지 Vol.22 No.2

다품종 소량생산이 보편화 되면서 하나의 생산라인에서 여러 종류의 제품을 교대로 생산하는 혼류생산방식이 보편화 되었다. 하지만 흐름라인 방식의 혼류생산에서는 필연적으로 작업장 간의 공정시간 불균형이 존재한다. 따라서 이러한 공정불균형에 의한 대기의 낭비를 최소화하기 위하여 기존의 흐름생산방식에서 셀생산방식으로 전환하는 시도가 빈번하게 발생한다. 본 논문에서는 굴삭기 부품을 생산하는 혼류흐름라인 방식의 자동화 로봇 용접라인을 FMC 개념의 직선형 셀방식으로 전환하는 과정에서 타당성 검토를 위해 시뮬레이션을 수행한 사례연구 결과를 소개한다. 분석결과 26.7%의 생산량 증가와 55% 이상의 리드타임 감소효과가 예상되었다. 또한 향후 제품 생산비율의 변화에 따른 민감도분석을 수행하였다. Mixed model production system means that various products are manufactured alternately in a line, and it has become a popular system in the era of multi-product small-quantity production. However, in the mixed model production system using flow line, the unbalance among stations is not inevitable because the workloads of stations cannot be the same. Thus, flow line system has been replaced to cellular manufacturing system for reducing the loss of waiting due to the unbalance of stations. In this paper, we introduce the simulation case study of an automated welding line which produces the parts of excavator. The factory has considered replacing the mixed model flow line to the cellular manufacturing system based on FMC concept. The increase of production quantity is estimated about 26.7%, and the lead time is reduced more than 55%. Furthermore sensitivity analyses are conducted considering the changes of product-mix.

콘텐츠라인- ‘전자정부 컨퍼런스 및 전시회 2005’ 성황리 폐막

김혜정,Kim, Hye-Jeong 한국데이터베이스진흥원 2005 디지털콘텐츠 Vol.6 No.-

한국데이터베이스진흥센터는 포스닥 전자정부연구소, 한국경제신문사와 공동으로 지난달 3일 서울 한국과학기술회관 대강당에서 열린우리당 원혜영 정책위 의장, 한나라당 권오을 정치개혁특위 위원장, 중앙부처 정보화 담당관 등 500여명이 참석한 가운데 ‘전자정부 컨퍼런스 및 전시회 2005’를 개최했다.

結節 紅斑에 對한 文獻的 考察

김혜정,채병윤,Kim, Hae-Jung,Chae, Bhung-Yoon 대한한방안이비인후피부과학회 1997 한방안이비인후피부과학회지 Vol.10 No.1

Erythema nodosum is a nodular erythematous eruption usually limited to the low extremities. Erythema nodosum seems to be Gwadungjun(瓜藤纏) and Damp-heat flow(濕毒流注) in oriental medicine. The symptom of erythema nodosum is similar to that of Gwadungjun, so we investigated the literatures of oriental medicine and recet medicine. The results were summarized as follows; 1. In Oriental medicine, erythema nodosum regarded as Damp-heat flow and Gwadungjun. 2. Inflammatory nodus of lower extremity, ie, similar to Gwadungjun, Damp-heat flow, Bichonbal(비천發), Samnibal(三里發), Ududok(魚두毒), etc. 3. Erythema nodosum results from inner damp-heat(內有濕熱), affection due to pathogenic wind(外感風邪). 4. Treatment is to clear away heat(淸熱), remove dampness(利濕), heat from blood(凉血), cold-damp(祛寒), and promote blood flood(活血通絡). 5. We can use Bangpungtongsungsan(防風通聖散), Sopunghwa1hyultang(疏風活血湯), and Danguijumtongtang(當歸拈通湯), etc.

A Case of Congenital Adrenal Hyperplasia Mimicking Cushing’s Syndrome

김혜정,강미라,Jae Hyeon Kim,김선욱,Jae Hoon Chung,Yong-Ki Min,이문규,Kwang-Won Kim,Myung-Shik Lee,김덕경,민용기 대한의학회 2012 Journal of Korean medical science Vol.27 No.11

Congenital adrenal hyperplasia (CAH) is characterized by decreased adrenal hormone production due to enzymatic defects and subsequent rise of adrenocorticotrophic hormone that stimulates the adrenal cortex to become hyperplastic, and sometimes tumorous. As the pathophysiology is basically a defect in the biosynthesis of cortisol, one may not consider CAH in patients with hypercortisolism. We report a case of a 41-yr-old man with a 4 cm-sized left adrenal tumorous lesion mimicking Cushing’s syndrome who was diagnosed with CAH. He had central obesity and acanthosis nigricans involving the axillae together with elevated 24-hr urine cortisol level, supporting the diagnosis of Cushing’s syndrome. However, the 24-hr urine cortisol was suppressed by 95% with the low dose dexamethasone suppression test. CAH was suspected based on the history of precocious puberty, short stature and a profound suppression of cortisol production by dexamethasone. CAH was confirmed by a remarkably increased level of serum 17-hydroxyprogesterone level. Gene mutation analysis revealed a compound heterozygote mutation of CYP21A2 (I173N and R357W).

脫毛에 對한 臨床的 考察

김혜정,채병윤,Kim, Hae-Jung,Chae, Byung-Yoon 大韓外官科學會 1996 大韓外官科學會誌 Vol.9 No.1

The alopecia is classified to Alopecia areata, Telogen effluvium, Anagen effluvium and Androgenetic alopecia. The exact cause of alopecia is not known, but a inherent and immunologic anc psychosomatic and endocrinic factors are suspected. We analysed clinical study in 77 patients, who had visited to the Dept. of Dermatology, Hospital of Oriental Medicine, Kyung Hee University to treat alopecia from June, 1994 to March, 1995. The results were summarized as follows; 1. In the series of 77 patients, $52\%\;were\;male\;and\;48\%$ were female. The peak incidence of age group was 20 to 29 ($55\%$). 2. The peak incidence of age group at on set was 20 to 29 ($49\%$). 3. The most frequent feature was insomnia ($25\%$). Frequent appeared signs and symptoms in descending order were head itching, head scale, fatigue and dizziness. 4. The personal history of patient were seborrheic dermatitis ($17\%$), atopic dermatitis, disorder of thyroid gland and acne in descending order. 5. The patients with family history occupied $25\%$. 6. Shineung Yangjin Dan was most used in treatments as $36\%$.

양택 풍수지리의 방위관 - "택경(宅經)"을 중심을 -

김혜정,Kim, Hye-Jung 한국건축역사학회 2009 건축역사연구 Vol.18 No.2

This research was to analyze the direction ideas of residential Feng Shui. In ancient China residential places were been established by Xiangzhai(相宅) and Buzhai(卜宅) usages. And ancient Chinese always considered geographical features of mountains and waters for setting up their living places. Geographical features were also considered importantly ih representative residential Feng Shui books, Zhaijing(宅經) and Yangzhaisanyao(陽宅三要). In Zhaihing, 24 direction ideas are co-related with Fagui(八卦) and GanZhi(千支) theories, and they are most important residential Feng Shiui direction theories. The basic thoughts of 24 direction ideas of Zhaijing were already formed in Qin(秦) dynasty and modified in early Han(漢) dynasty. In Zhaijing, residential places were splited into Yangzhai(陽宅) and Yinzhai(陰宅) according to YinYang's Qi directions. Those were actually formed from meticulous observations on changing processes of YinYangWuXing(陰陽五行)'s Qi(氣). Constantly changed Qi of YinYangWuXing were studied by old chinese people from the observations on the sun, the moon, the five stars, the Great Bear, and ErShiBaXiu(二十八宿). The origin of Zhaijing's direction ideas is the direction system of ShiPan(式盤) in Qin and Han dynasty. On ShiPan TianGan(天干) Dizi(地支) Fagui TianDiRenGui(天地人鬼) were arranged very systematically into four and 24 directions. DongxiSizhai(東西四宅) theories of Yangzhaisanyao had edited more lately than Zhaijing(宅經), and formed according to Fagui(八卦)'s YinYang(陰陽) principles. But the basic ideas is same with Zhaihing's. It proves that residential Feng Shui theories were constantly improved and modified. And both residential Feng Shui direction ideas of Zhaijing and Yangzhaisanyao are the gentral ideas in old china. The point of that ideas is Sky's four or 24 directions are correspndence with the earth's. It came from the traditional thoughts that Heaven, Earth, and mankind are c0-related and influenced each other according to Qi's changing processes. Gather up above mentioned, the direction ideas of residential Feng Shui is a systematic thoughts of old chinese for harmonizing Tian-Di-Ren-Gui, and is their specific methods for harmonizing the nature's Qi, mankind and spirits.