• Toxicological Research
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• v.28 no.4
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• pp.209-216
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• 2012

The biological activity of particles is largely dependent on their size in biological systems. Dispersion in the aqueous phase has been both a critical impediment to and a prerequisite for particle studies. Carbon black has been used as a surrogate to investigate the biological effects of carbonaceous particles. Here, biocompatible methods were established to disperse carbon black into ultrafine and fine particles which are generally distinguished by the small size of 100 nm. Carbon black with a distinct particle size, N330 and N990 were suspended in blood plasma, cell culture media, Krebs-Ringer's solution (KR), or physiological salt solution (PSS). Large clumps were observed in all dispersion preparations; however, sonication improved dispersion - averaged particle sizes for N330 and N990 were $85.0{\pm}42.9$ and $112.4{\pm}67.9$ nm, respectively, in plasma; the corresponding sizes in culture media were $84.8{\pm}38.4$ and $164.1{\pm}77.8$ nm. However, sonication was not enough to disperse N330 less than 100 nm in either KR or PSS. Application of Tween 80 along with sonication reduced the size of N330 to less than 100 nm, and dispersed N990 larger than 100 nm ($73.6{\pm}28.8$ and $80.1{\pm}30.0$ nm for N330 and $349.5{\pm}161.8$ and $399.8{\pm}181.1$ nm for N990 in KR and PSS, respectively). In contrast, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) exhibited little effect. Electron microscopy confirmed the typical aciniform structure of the carbon arrays; however, zeta potential measurement failed to explain the dispersibility of carbon black. The methods established in this study could disperse carbon black into ultrafine and fine particles, and may serve as a useful model for the study of particle toxicity, particularly size-related effects.

• The Optical Journal
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• s.119
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• pp.85-91
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• 2009

올해 중고기업 정책자금이 지난해 3조 2000억원 보다 35% 늘어난 4조 3000억원으로 확정됐다. 중소기업청은 지난 12월 22일 이 같은 내용을 골자로 한 '2009년도 중소기업 정책자금 운용계획'을 발표하고, 올해 상반기중 자금의 70% 이상을 조기 집행한다고 밝혔다. 올해는 정책자금의 기준 금리를 지난해의 5.91%에서 5.07%로 0.84%포인트 인하하고, 자금을 기능강화(창업초기기업 개발기술 사업전환) 분야와 시장보완(신성장기반 지방주소기업지원 긴급경영안정 소상공인) 분야로 구분해 각각 4.37%, 4.74%의 차등 금리를 적용키로 했다. 각 자금에 대한 설명자료 및 신청방법 등은 중소기업진흥공단 홈페이지(www.sbc.or.kr)를 통해 안내받을 수 있다.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2007.06a
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• pp.81-85
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• 2007

반도체 공정에서 식각 공정을 위한 패턴 형성 시, 현상을 위해 포토레지스트를 도포한다. 이 포토레지스트는 일정한 두께로 도포 되어야 하기 때문에 고도의 정밀성이 요구되는 공정이며, 공정 불량이 빈번하게 발생한다. 이러한 공정 불량 발생 시 현재 양산에서는 매엽식 장비로 애싱 전 처리 한 후, 약액 처리를 위해 낱장의 웨이퍼를 일정량 모아서 배치식 장비로 처리한다. 이렇게 되면 공정 불량 발생시, 약액의 소모를 줄이기 위해서는 일정량 모아질 때까지 대기하여 처리하여 시간 소모가 커지며, 시간 소모를 줄이기 위해서는 낱장으로 처리하여야 하기 때문에 약액 손실이 커져 비경제적일 수 밖에 없다. 따라서 본 연구에서는 이러한 문제점을 해결하기 위해, 매엽식 장비로 무기 용제를 이용하여 효율적으로 포토레지스트를 제거하는 방법에 대해서 평가를 실시하였다. 평가 결과 krF 포토 레지스트 웨이퍼에 대해서 완전 박리하는 결과를 얻었으며, 160nm 기준 파티클 50개 미만의 결과를 얻었다.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.23-23
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• 2003

Chestnut blight, caused by Cryphonectria parasitica, is the most destructive disease of American and European chestnut trees. A total of 672 C prasitica was isolated from blight lesion on chestnut twigs, which were collected from major chestnut plantations all over Korea in 1999. Isolation rates were over 30% in Kyunggj-, Kyongnam-, and Chonnam-do. The highest isolation rate was 37.4% and recorded in Kyongnam-do. On the other hand, Chonbuk-do had the lowest isolation rate as 13.5%. In grouping of C parasitica by colony shape and color, yellow colony with irregular margin were the most dominant colony type with a frequency of 65.2%. When the 672 isolates were inoculated on the chestnut twigs, 380 isolates (56.5%) caused lesions larger than the standard virulent isolate EP155-2, while 158 isolates (23.4%) caused smaller lesions than the standard hypovirulent isolate UEP-1. In Bavendamm test that determines phenol oxidase activity, 97.1% of all the isolates resulted the same or darker discoloration than EP155-2, and only 12.2% resulted the same or lighter discoloration than UEP-1. In the vegetative compatibility (VC) tests, total 670 isolates were divided into 121 VC groups (VCGs). Kyongnam-, Chonnam-, and Chungnam-do, the three principal chestnut plantation area, had 49, 33, and 27 VCGs, respectively. Among the VCGs, the biggest VCG, KR-VC104, was composed of 164 isolates and the second biggest VCG had 62 isolates. But, 64 of 121 VCGs consisted of sole member. More than 65.8% of KR-VC104, was isolated from the three provinces, Kyongnam-, Kangwon-, and Chungbuk-do. In KR-VC104, 62.8%, 59.1%, and 85.9% of the isolates looked like virulent in colony type, pathogenicity test, and Bavendamm test. In ds-RNA detection tests using cellulose chromatography, 77 of total 650 isolates were ds-RNA positive and detected ds-RNA segments were approximately 12kb, 3kb, 2.7kb, 2kb, and 1.8kb in size. Among the 77 isolates, 46 isolates had 12kb and 25 isolates had 12kb and 2.7kb. Other 6 Isolates had small ds-RNA segments. Kyongnam-, Chonnam-, and Chungnam-do had 43, 16, and 5 ds-RNA positive isolates, respectively. Among the 121 VCGs, only 29 VCGs had ds-RNA positive isolates.(중략)

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.3
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• pp.301-308
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• 2018

Anthropogenic radioactive noble gases formed by nuclear fission are significant indicators used to monitor the nuclear activity of neighboring countries. In particular, radioactive xenon, owing to its abundant generation and short half-life, can be used to detect nuclear testing, and radioactive krypton has been used as a tracer to monitor the reprocessing of nuclear fuels. Released radioactive noble gases are in the atmosphere at infinitesimal amounts due to their dilution in the air and their short half-life decay. Therefore, to obtain reliable and significant data when performing measurement of noble gases in the atmosphere, the minimum detectable activity (MDA) for noble gases should be defined as low as possible. In this study, the MDA values for radioactive xenon and krypton were theoretically obtained based on the BfS-IAR system by collecting both noble gases simultaneously. In addition, various MDA methods, confidence level and analysis conditions were suggested to reduce and optimize MDA with an assessment of the factors affecting MDA. The current investigation indicated that maximizing the pretreatment efficiency and performance maintenance of the counter were the most important aspects for Xe. In the case of Kr, since sample activities are much higher than those of Xe, it is possible to change the target MDA or to simplification of the analysis system.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.4
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• pp.301-307
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• 2005

The morphology of the high burnup $UO_2$ spent fuel, which was oxidized and annealed in a PIA (Post Irradiation Annealing) apparatus, has been observed. The high burnup fuel irradiated in Ulchin Unit 2, average rod burnup 57,000 MWd/tU, was transported to the KAERI's PIEF. The test specimen was used with about 200 mg of the spent $UO_2$ fuel fragment of the local burnup 65,000 MWd/tU. This specimen was annealed at $1400^{\circ}C$ for 4hrs after the oxidation for 3hrs to grain boundary using the PIA apparatus in a hot-cell. In order to oxidize the grain boundary, the oxidation temperature increased up to $500^{\circ}C$ and held for 3hrs in the mixed gas (60 ml He and 100 ml STD-air) atmosphere. The amount of 85Kr during the whole test process was measured to know the fission gas release behavior using the online system of a beta counter and a gamma counter. The detailed micro-structure was observed by a SEM to confirm the change of the fuel morphology after this test. As the annealing temperature increased, the fission products were observed to move to the grain surface and grain boundary of the $UO_2$ matrix. This specimen was re-structured through the reduction process, and the grain sizes were distributed from 5 to $10\;{\mu}m$.

• Korean Chemical Engineering Research
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• v.46 no.4
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• pp.681-685
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• 2008

Chiral separation of racemic mandelic acid was achieved on a Kromasil KR100-5CHI-TBB column. Some chromatographic parameters (resolution, number of theoretical plates, capacity factor) are calculated under different separation conditions such as changes of mobile phase compositions (hexane/t-BME = 85/15 - 10/90) as well as formic acid concentrations for adjusting pH (0.1, 0.5, 1.0 v/v%). Flow rate versus number of theoretical plates was compared to evaluate column efficiency. To determine the adsorption isotherms, PIM (Pulse Input Method) was carried out. At the concentrations of racemic mandelic acid between 0.1 and 0.3 mg/ml, L- and D-mandelic acids have the same retention times of 8.8 and 9.4 min respectively. Mandelic acid isotherms show a linear form under the concentrations of 0.3 mg/ml with eluent (hexane/t-BME = 75/25). As the concentrations of mandelic acids increase, nonlinear Langmuir isotherms were observed as $C_{S,L}=3.358C_{M,L}/(1+0.0897C_{M,L})$ for L-mandelic acid and, $C_{S,D}=3.692C_{M,D}/(1+0.1457C_{M,D})$ for D-mandelic acid.

• Journal of Korean Medicine for Obesity Research
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• v.8 no.2
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• pp.1-13
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• 2008

Objective This study was designed to collect latest papers and to find more effective approach for Postmenopausal Women Methods We searched 85 papers in English from Pubmed(www.ncbi.nlm.nih.gov) and selected 40 in favor of our study. In addition to that, we searched 24 papers in Korean from Kiss(www.kiss.kstudy.com) and Medric(www.medric.or.kr). Results are as follows. Results and conclusion Many studies showed that postmenopausal obesity causes cardiovascular disease, osteoporosis, breast cancer and decrease in immunity. To prevent and treat obesity, many studies suggested that dietary and exercise are most effective methods. If needed, medicine and hormone therapy may be recommended as next steps. But, Herb medication and acupuncture are not used yet as postmenopausal obesity treatment around the world. Postmenopausal obesity is significant, resulting in many medical problems. We hope more effective treatment based on these studies and combined with Korean traditional medicine could be developed after.

• The Optical Journal
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• s.143
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• pp.78-85
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• 2013

올해 중소기업 정책자금 지원규모는 3조 8500억 원으로 지난해 3조 3330억 원에서 15.5% 증가한다. 중소기업청과 중소기업진흥공단은 정책자금의 우선순위를 일자리 창출에 두고 민간금융기관을 통해 자금 조달이 어려운 창업자와 기술개발기업에 전체 정책자금의 40.3%인 1조 5500억 원을 배분한다. 이에 창업기업지원자금이 지난해보다 200억 원, 개발기술사업화자금이 420억 원 늘어나며, 정책자금을 지원받은 기업이 일자리를 1명씩 늘릴 때마다 0.1%포인트씩 최대 1%포인트까지 금리를 인하해 일자리 창출 효과를 극대화 한다는 계획이다. 또한 중진공을 통한 직접 대출 비중이 기존 55%에서 70%로 확대되며, 개발기술사업화자금, 수출금융, 소공인 특화자금은 전액 직접대출로 운영되고 운전자금에 대한 보증서부 대출은 폐지된다. 반면 신용대출 규모는 20% 늘어나 중소기업의 담보 부담이 줄어들 전망이다. 변화하는 산업 구조에 맞춰 정책자금 구조도 바뀐다. 담보력이 부족한 창업 및 소기업의 자금 지원을 위해 기계기구, 재고자산, 매출채권의 담보 인정비율을 높인다. 하반기 중에는 지식재산권 담보대출이 새로 도입된다. 별도의 기술가치 평가 모형을 통해 특허기술의 경제적 가치를 평가하고 특허권을 담보로 대출을 시행한다. 자세한 사항 및 정책자금 신청 희망기업은 중소기업진흥공단 홈페이지(www.sbc.or.kr) '정책자금 융자도우미'를 통해 신청요건 및 추천자금 등을 자가진단 후 신청하면 된다.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1661-1668
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• 2016

A fixed off-time controlled high power factor ac-dc LED driver is proposed in this paper, which employs a novel zero-crossing-compensation (ZCC) circuit based on a fixed off-time controlled scheme. Due to the parasitic parameters of the system, the practical waveforms have a dead region. By detecting the zero-crossing boundary, the proposed ZCC circuit compensates the control signal VCOMP within the dead region, and is invalid above this region. With further optimization of the parameters KR and Kτ of the ZCC circuit, the dead zone can be eliminated and lower THD is achieved. Finally, the chip is implemented in HHNEC 0.5μm 5V/40V HVCMOS process, and a prototype circuit, delivering 7~12W of power to several 3-W LED loads, is tested under AC input voltage ranging from 85V to 265V. The test results indicate that the average total harmonic distortion (THD) of the entire system is approximately 10%, with a minimum of 5.5%, and that the power factor is above 0.955, with a maximum of 0.999.