• 한국전기전자재료학회논문지
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• 제24권3호
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• pp.234-239
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• 2011

In this study, the heat transfer capability have been improved by using via-holes in FR4 PCB, when the LED lighting is designed to solve the thermal problem. The thermal resistance and junction temperature were measured by changing the dimension of FR4 PCB and size of via hole. As a result, when the dimension was increased initially, the thermal resistance and junction temperature was decreased rapidly, the ones was stabilized after the dimension of 200 $[mm^2]$. Also, the light output was improved up to maximum 17% by formation of via-hole and expansion of dimension in FR4 PCB. Therefore, the thermal resistance and junction temperature could be improved by expansion of PCB dimension and configuration of via-hole ability.

• 구강회복응용과학지
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• 제35권3호
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• pp.160-169
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• 2019

목적: 이번 연구의 목적은 정적인 방법과 동적인 방법으로 형성된 지르코니아 표면에 부착된 바이오필름에 대한 LED 칫솔의 항균 효과를 평가하고자 하였다. 연구 재료 및 방법: 구강 바이오필름을 형성하기 위해 직경 12 mm, 두께 2.5 mm의 지르코니아 디스크를 24-well plate(정적 방법)와 Center for Disease Control and Prevention (CDC) biofilm reactor (동적 방법)에 디스크를 넣어 바이오필름을 형성하였다. 디스크는 아무 처치도 하지 않은 대조군, 상용화된 광역학(PDT) 키트, 치솔질(brushing) 단독, LED 치솔군, LED 치솔과 에리스로신을 같이 적용한 군, 이렇게 5개 그룹으로 구성하였다. 각 군별 처치 후, 개별 디스크를 시험관에 넣고 60 초 동안 vortexing하여 세균을 분리한 후, 분리된 세균 용액을 선택 배지를 이용하여 살아있는 세균 수를 확인한 후 실험 방법에 따른 항균 효과를 계측하였고, 주사전자현미경(SEM)을 통하여 세균의 형태 변화를 관찰하였다. 결과: 바이오필름의 형성과 구성비는 동적인 방법과 정적인 방법에 따른 차이는 관찰되지 않았다. 대조군과 실험군간에 세균의 생존률에 유의한 차이가 있었다(P < 0.05). LED 치솔과 에리스로신을 같이 적용한 군에서 가장 높은 항균 효과가 관찰되었다(P < 0.05). 주사전자현미경 사진상에서 광역학치료군과, LED 치솔군, LED 치솔과 에리스로신을 같이 적용한 군은 세균의 형태 변화가 관찰되었으나, 대조군과 치솔질 단독 사용군에서는 세균의 형태 변화가 관찰되지 않았다. 결론: 이번 연구 결과 지르코니아 표면에 부착된 바이오필름을 효과적으로 제거하는 방법으로 LED 치솔과 에리스로신을 같이 적용하는 것이 추천된다.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2019년도 추계학술대회
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• pp.45-45
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• 2019

This experiment was carried out using artificial clay and LED in the plastic film house (irradiation time: 08:00~18:00/day). Seedlings (n = 63 per $3.3m^2$) of ginseng was planted on May 17, 2018. LED was combined with red and blue light in a 3:1 ratio and irradiated with different light intensity. The average air temperature from April to September was $12.3^{\circ}C$ $-26.0^{\circ}C$ and it was the the highest at $26.0^{\circ}C$ in August. The test area where fluorescent lamp was irradiated tended to be somewhat higher than the LED irradiation area. The chemical properties of the test soil are as follows. pH levels was 5.3~5.5, EC levels 0.45~0.52 dS/m and OM levels 33~37%. The total nitrogen content was 0.35~0.47% and the available $P_2O_5$ contents was 13.7~16.0 mg/kg, which was lower than the suitable level of 70~200 mg/kg. Exchangeable cations K and Mg contents were within acceptable ranges, but the Ca contents was $28{\sim}38cmol^+/kg$ levels higher than the permissible level ($2{\sim}6cmol^+/kg$). Germination of ginseng leaves took 8~9 days and the overall germination rate was 70~75%. The photometric characteristics of LED light intensity are as follows. The greater the light intensity, the higher the PAR (Photosynthetic Action Radiation) value, illuminance and solar irradiation. Photosynthetic rate was also increased with higher light intensity was investigated at $1.7{\sim}3.2{\mu}mol\;CO_2/m^2/s$. Leaf temperature ($23.7{\sim}24.8^{\circ}C$) by light intensity was the same trend. The growth of aerial parts (plant height etc.) were generally excellent when irradiated with 3 times the light intensity, the growth of the ginseng aerial parts were excellent as follows. The plant height was 42.6 cm, stem length was 25.2 cm, leaf length was 9.6 cm and stem diameter was 5.0 mm. The growth of underground part (root length etc.) was the same, and the root length was 24.4 cm, the tap root length was 6.0 cm, diameter of taproot was 18.2 mm and the fresh root weight was 17.2 g. There were no disease incidence such as Alternaria blight, Gray mold and Anthracnose. Disease of Damping off occurred 2.2~3.6% and incidence ratio of rusty root ginseng was 14.6~20.7%. Leaf discoloration rate was 13.7~48.9% and increased with increasing light intensity. Ginsenoside content of ginseng by light intensity is under analysis.

• Restorative Dentistry and Endodontics
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• 제27권6호
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• pp.561-568
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• 2002

Purpose of this research is estimating polymerization depth of different source of light. XL 3000 for halo-gen light, Apollo 95E for plasma arc light and Easy cure for LED light source were used in this study. Different shade (B1 & A3) resin composites (Esthet-X, Dentsply, U.S.A.) were used to measure depth of cure. 1, 2, and 3 mm thick samples were light cured for three seconds, six seconds or 10 seconds with Apollo 95E and they were light cured with XL-3000 and Easy cure for 10 seconds, 20 seconds, or 40 seconds. Vicker's hardness test carried out after store samples for 24 hours in distilled water. Results were as following. 1. Curing time increases from al1 source of lights, oui$.$ing depth increased(p<0.05). 2. Depth (that except 1mm group and 2mm group which lighten to halogen source of light) deepens in all groups, Vickers hardness decreased(p<0.05). 3. Vicker's hardness of A3 shade composite was lower in all depths more than B1 shade composites in group that do polymerization for 10 seconds and 20 seconds using halogen source of light(p<0.05), but group that do polymerization lot 40 seconds did not show difference(p>0.05). 4. Groups that do polymerization using Plasma arc and LED source of light did not show Vicker's hardness difference according to color at surface and 1mm depth(p>0.05), but showed difference according to color at 2mm and 3mm depth(p<0.05). The results showed that Apollo 95E need more polymerization times than manufacturer's recommendation (3 seconds), and Easy cure need polymerization time of XL-3000 at least.

• 소성∙가공
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• 제24권2호
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• pp.95-100
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• 2015

It was confirmed that when phosphor slurry is formed in the cavity of an elastic mold, the pressure distribution of the phosphor slurry varies as a function of the major squeegee parameters (squeegee angle, squeegee velocity, and the viscosity of the phosphor slurry). The higher the slurry viscosity, the faster the squeegee velocity, and the smaller the squeegee angle, the higher the filling completeness of the phosphor slurry. The optimum conditions for complete filling of the phosphor slurry were found when the squeegee angle was between 30 to 45 degrees, squeegee velocity at 40 to 70mm/sec, and the viscosity of the phosphor slurry composite was at 6,556 cps (i.e. phosphor content around 50 wt. %).

• 대한소아치과학회지
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• 제32권2호
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• pp.332-343
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• 2005

본 연구에서는 기존의 할로겐 광중합기를 이용하여 40초간 조사하여 복합레진을 중합한 경우와 플라즈마 광중합기를 이용한 고강도의 중합 및 완속기시 중합 방식, 그리고 LED 광중합기를 이용한 통법의 중합과 완속기시 중합 방식으로 복합레진을 중합하여 발생되는 수축응력을 비교하고 미세경도를 측정하여 중합도를 평가하였다. 내경 7mm, 외경 10mrn의 아크릴릭 주형을 제작하고 외면에 스트레인게이지를 부착시킨 뒤 각각의 광원에 따른 중합모드로 광중합 하였다. 광조사 시점부터 1초 간격으로 600초간 수축응력을 측정하였으며, 중합 24시간 후 각 군의 미세경도를 측정하여 통계 분석하였다. 수축응력 측정 후 시편을 종단하여 주사전자현미경으로 레진수복물과 아크릴릭 주형 계면을 관찰하였다. 이상의 실험을 통해 얻은 결과는 다음과 같다. 1. 플라즈마 광과 LED 광원의 완속기시 중합방식은 각각의 기본 중합방식에 비해 중합 10분 후에 수축응력 감소를 보였다(P<0.05). 2. 완속기시 중합방식의 플라즈마 광이 가장 낮은 수축응력을 보였으나 미세경도 또한 가장 낮았다(P<0.05). 3. 완속기시 중합방식의 LED 광중합은 기존의 할로겐 광과 LED 광중합 방법에 비하여 낮은 수축응력을 보였다(P<0.05). 4. 완속기시 중합방식의 LED 광으로 조사한 시편의 미세경도는 단일광도로 조사한 할로겐 광과 LED 광중합과 비교하여 유의할만한 차이가 나타나지 않았다(P>0.05). 5. 기존의 할로겐 광과 완속기시 중합방식의 LED로 중합한 시편이 플라즈마 광과 단일강도의 LED로 조사한 군보다 더 나은 변연봉쇄를 보였다.

• 대한치과보철학회지
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• 제25권1호
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• pp.71-94
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• 1987

This study was carried out to investigate the sound distortion following the alternation of the palatal plate thickness. For this study, 2 healthy male subjects (24-year-old) were selected. Born in Seoul, they both spoke Seoul dialect. First, their sounds of /na(나)/, /da(다)/, /1a(라)/, /ja(자)/, /cha(차)/, /ta(타)/, without inserting plates were recorded, and then the sounds with palatal plates of different thickness were recorded, successively. The plate was fabricated in 3 types, each palatal thickness being 1.0mm, 2.5mm, dentoalveolar portion 2.5mm, other residual portion was 1.0mm, successively. Each type plates named B, C, D-type, in succession. Series of analysis were administered through Computer(16 bit) to analyze the sound distortions. These experiments were analyzed by the LPC (without weighting, pre-weighting, post-weighting) of the consonants, vowels portion, formant frequency of the vowels and word duration of the consonants. The findings led to the following conclusions: 1. There was no correlation of the distortion rate on the 2 informants. 2. Generally, vowels were not affected by the palatal plate thickness in the formant analysis, however, more distortion was detected in the LPC analysis, especially C, D-type plates. 3. Consonants distortion was more evident in the C, D-type plate. 4. The second formant was most disturbed and reduced in the all consonants with insertion of the palatal plate, especially C, D-type plate. 5. Word duration was shortened in the plate inserted(except /ja/, /cha/), especially C, D-type. 6. It was found that dentoalveolar, hard palatal sounds were severely distorted in plate inserted, and they were mainly affected by the dentoalveolar portion thickness. 7. There was correlation between palatal thickness and consonants quality.

• 대한치과보철학회지
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• 제27권1호
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• pp.83-102
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• 1989

This study was done to analyze the sound distortion, before and after insertion of the palatal palates. For this study, 4 healthy subjects (3 males and 1 female, each 24-year-old), who were born in Seoul were recruited from K university, and 3 type palatal plates were fabricated, each palatal thickness being 1.0mm, 2.5mm, dentoalveolar portion 2.5mm and elsewhere 1.0mm, named B,C,D-type repectively, and informants's sounds of /사(sa), 서(se), 소(so), 수(su), 스($s\.{+}$), 시(si)/ were recorded, without plate, and with palatal plates of different types, in succession. A series of analysis were adminstered through a 16 Bit IBM PC/AT using linear combination methods. These experiments were analyzed by the Cepstrum (Weighted and Euclidian), Log Area Ratio, Linear prediction correlation methods The findings led to the following conclusions : 1. It was confirmed that the same consonant, /ㅅ(s)/, variously distorted by the following vowel. 2. By and large, 시($s\.{+}$) was the most distorted in all conditions, and (sa), 소(so) were the least distorted in each condition. 3. There were no persistant correlation of the palatal plate types, and sound distortions of each informant were diverse with no regularities. 4. There were persistent correaltion to the Cepstrum (Weighted, Euclidian), Log Area Ratio. However, Linear prediction correlation has a different alteration pattern.

• Journal of Korean Dental Science
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• 제16권2호
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• pp.172-181
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• 2023

Purpose: To investigate the effect of epidermal growth factor (EGF) with collagen matrix (CM) for increasing gingival thickness. Materials and Methods: In five mongrel dogs, bilateral gingival defects were surgically made on the maxillary canines. After two months, either a subepithelial connective tissue graft (group SCTG) or CM with EGF (0.1 ug/ml, group EGF) was grafted, and the flap was coronally positioned to cover the graft materials. The animals were sacrificed after three months. Intraoral scanning was performed for soft tissue analysis. Histologic and histomorphometric analyses were performed. Result: Two animals exhibited wound dehiscence during the healing phase, leaving three for analysis. No statistically significant difference was found in soft tissue changes (P>0.05). The level of gingival margin (GM) increased in both groups (1.02±0.74 mm in group SCTG vs. 1.24±0.83 mm in group EGF). Linear increases at the GM pre-augmentation in the soft tissue profile were 1.08±0.58 mm in group SCTG and 0.96±0.73 mm in group EGF. Histomorphometric parameters (keratinized tissue height, tissue thickness, and rete peg density) were not significantly different between the groups (P>0.05). Conclusion: EGF loaded onto CM led to comparable gingival phenotype enhancement to SCTG.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.1398-1400
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• 2002

A new PLF-BLU (Plastic Light Fiber-Back Light Unit) using side glowing light fiber rods array for the 42" LCD TV display has been evelopedd. The light fibers were 14mm in diameter and 50cm long pure transparent acrylic rods of 1.49 refractive index. Fine seratees were made on the flat side of rod. extremely bright incandscent light from lamp fed into the fiber si scattered at scratches then emerges through the surface of rod. A typical PLF-BLU system consists of 24 PLFs produced side glow of brightness of 4,500cd/㎡ to 6,500cd/㎡. New PLF-BLU is proved to be a BLU of rigid, bright, no heat generation, and low power consumption, hence a prospective BLU system for very and/or ultra large size TVs. A new LED-PLF-BLU system considered to be a revolutionary to break-through of the BLU technologies has also been developed, and is decribed briefly.