黑心可鍛鑄鐵의 燒鈍에 依한 黑鉛化의 生成에 關한 硏究

李龍鎬,南勝義,宋昌燁 弘益大學校 1981 弘大論叢 Vol.13 No.-

The previous report stated that the direct graphitizing process without decomposition of pearlite could be practised experimentally in malleable cast iron annealing, that is, by holding the iron for about sixtyhours. After cooling transformation begins, a fully ferritized malleable cast iron is obtained. It has also been clarified that it is rather difficult to keep the castings in such narrow temperature range as 730 to 740℃ under foundry conditions. With the view of investigating the resolution vehavior of pearlite remaining after direct graphitiaztion into austenitic matrix, specimens haveing bull's eye structure or pearlite were quenched after holding for various periods at predetermined temperatures and their microstructures were examined. The results obtained are summarized as follows: 1) The existence of a trace of cementite after resolution of pearlite into austenitic matrix when the specimen is reheated above critical temperatues accelerates the precipitation and growth of pearlite depending upon the volume and number of remaining pearlitic cementite during slow cooling through the critical range. In other words, a trace of cementite retards the direct graphitization in the critical range. 2) As lamellar pearlite precipitated during cooling deccomposes extremely slowly at subcritical temperatures, it is important to prevent the formation of pearlite during cooling in order to have the direct graphitization completed during slwo cooling in the appropriate temperature range. 3) It is necessary to hold the iron for at least 1hr. at 900℃ to dissolve the pearlitic cementite into austenite. 4) It was found by the author's experiment that a blackherat malleable iron having fully ferritized matrix can be obtained by extremely slow cooling through critical direct-graphitzing temperature range. Ⅰ. 緖 言 Ⅱ. 基礎理論 Ⅲ. 實驗方法 Ⅲ-1 試料의 製作 Ⅲ-2 實驗器機 Ⅲ-3 實驗方法 Ⅳ. 實驗結果 및 考察 Ⅳ-1 加熱溫度에 따른 黑鉛化 Ⅳ-2 黑鉛化에 미치는 維持時間의 影響 Ⅳ-3 反復 加熱 冷却時 黑鉛化 및 機械的 性質 Ⅳ-4 變態 範圍는 徐冷하여 長時間 等溫維持할 때의 黑鉛化 Ⅴ. 結 論

Cr₂O₃가 고주파용 Pb(Mn⅓Mb⅔)O₃+PZT 세라믹스기판의 압전 특성에 미치는 영향

이개명,박창엽,김규수 연세대학교 산업기술연구소 1991 논문집 Vol.23 No.2

핫프레스법으로 제작된 ?? 세라믹스에 있어서 Cr2O3의 첨가량이 그 시편의 구조적특성, 유전특성, 압전특성, 온도안정성 및 포아손비에 미치는 영향을 조사하였다. Cr2O3의 첨가량의 범위가 0.3∼0.75[wt%]인 시편만이 포아손비가 1/3 이상으로 주파수 저하형 에너지포획 소자의 기판으로 사용될 수 있으며, 이 중에서 Cr2O3의 첨가량이 0.5[wt%]인 시편이 보다 우수한 압전특성과 안정된 온도특성을 갖고 있다. The effects of Cr2O3 addition on the structural, dielectric, piezoelectric properties, Poisson ratio and temperature stability of hot-pressed ?? ceramics were investigated. Only the specimens with Cr2O3 amount, 0.3∼0.75[wt%]can be used as the substrate for energy trapped devices of frequency lowering type, because their Poisson ratios are larger than 1/3. And the specimen with 0.5[wt%]Cr2O3 of them, has better piezoeletric properties, and more stable frequency temperature characteristics than the others.

의무고용제도 재설계 방안

김종진,장창엽,유완식,김언아,이정주,류정진,강필수,최종철,남용현,김윤삼 한국장애인고용촉진공단 고용개발원 2008 연구개발 Vol.- No.2

현행 우리나라 의무고용제도는 장애인구의 급격한 증가, 장애인차별금지 및 권리구제 등에 관한 법률의 도입 등 외부환경변화에 신축적으로 대처하지 못하고, 경증장애인 중심으로 의무고용제도가 운영됨으로써 중증장애인의 고용배제가 우려되고 있다. 본 보고서는 이러한 문제점을 해결하기 위해 의무고용제도의 일자리 확대와 고용증가를 통해 중증장애인의 고용기회를 확대할 수 있는 정책방안을 제시하기 위한 것이다. 본 보고서는 (1)의무고용 사업체의 의무고용 산정인원에서 자립장애인 제외 (2)현행 2% 의무고용률을 3%로 상향 조정 (3)사업체가 고용하는 중증장애인에 대한 더블카운트(2배) 가산제도 도입 (4)의무고용률 미달 사업주에 대한 부담금 차등징수의 4가지 정책방안, 제도 합리화 차원에서 장려금 지급방식의 개선과 사업주의 장애인에 대한 인식개선 방안을 제시하였다. 정책방안에 대한 영향분석 결과 의무고용 적용대상자에서 비장애인과 고용상 차별되지 않는 자립장애인(6등급)을 의무고용 산정인원에서 제외하는 경우 의무고용 사업체의 고용인원은 23,296명이 감소해 고용률은 1.35%에서 0.88%로 감소하였고, 의무고용 사업체의 장애인 일자리 수는 미고용인원의 증가로 15,152개가 증가하였다. 그리고 기금은 부담금이 631억원 증가하고, 장려금이 352억원 감소해 983억원의 수지개선 효과가 발생하는 것으로 나타났다. 의무고용 사업주의 의무고용률 3% 인상 방안은 의무고용률 상향 조정에 따른 미고용인원의 증가로 장애인의 일자리 수는 43,101개가 증가하고, 기금은 부담금이 1,709억원 증가하는 반면, 장려금은 293억원이 감소해 2,002억원의 수지개선 효과가 발생하는 것으로 나타났다. 의무고용 사업주가 고용하는 중증장애인을 2인으로 더블카운트 하는 중증장애인 가산제도의 도입은 의무고용 사업체의 장애인근로자가 67,261명에서 79,685명(1,2등급만 포함시 75,685명)으로 증가하여 고용률은 1.35%에서 1.60%(1.2등급만 포함시 1.52%)로 증가하고, 의무고용률 미달 사업체의 미고용 인원이 감소하여 2,745개의 일자리가 감소하였다. 그리고 기금은 부담금이 118억원 감소하는 반면, 장려금은 418억원이 증가해 536억원의 수지악화가 발생하는 것으로 나타났다. 의무고용률 미달 사업체의 고용유인을 위해 고용률 1.0%미만, 1.0-1.5%, 1.6-2.0% 미만에 대해 각각 20%, 10%, 5%의 할증률을 순차적으로 가중하여 부과하는 부담금 차등징수 방안(3차년까지의 효과임)은 1.0% 미만 사업주는 86만원, 1.0-1.5% 사업주는 64만원, 1.6-2.0% 미만 사업주는 58만원의 부담기초액을 부과할 때 고용률은 1.35%에서 1.53%로 증가(1.6-2.0% 미만 사업주는 의무고용률 2%를 달성)하고, 미고용인원의 감소로 장애인의 일자리는 8,836개가 감소하는 것으로 나타났다. 그리고 기금은 부담금이 58억원 감소하여 수지는 악화되었다. 이상의 네 가지 방안은 모두 장애인의 고용증대를 가져온다는 측면에서는 유효하지만, 장애인의 일자리 확대를 통한 중증장애인의 고용을 증대한다는 정책목표를 달성하는 데에는 한계점을 안고 있기 때문에 어느 한 정책만을 선택하기보다는 정책효과를 극대화하기 위해 정책결합(policy mix)을 이용하는 것이 바람직함을 제시해주었다. 즉, 의무고용 적용대상자 조정방안/의무고용률 상향조정 방안과 중증장애인 가산제도/부담금 차등징수 방안을 조합 또는 모두 동시에 선택하는 경우 의무고용 사업체의 장애인 일자리 수의 확대와 중증장애인 고용을 동시에 달성하고, 기금의 수지균형도 달성 가능한 것으로 나타났다. The mandatory employment quota system of Korea does not reflect the changing external factors such as the growing population of people with disabilities(PWDs) and the enactment of the Anti-discrimination Law for People with Disabilities. The current employment quota system focuses on people with mild disabilities thus excluding people with severe disabilities from employment. The purpose of this report is to propose a plan in order to increase employment opportunity for the severely disabled through the reform of the employment quota system. This report analyzes the following : (1) exclude grade 6 disability from mandatory employment quota (2) raise the employment quota from 2% to 3% (3) implement the double counting for employers that employ the severely disabled (4) differentiate the amount of levy collected from corporations that are unable to meet the quota. The aforementioned plans are useful in that they increase employment for people with disabilities. However, there are limitation to reaching the policy objectives by increasing jobs for people with severe disabilities. Therefore, to maximize the effects we should consider policy mix of these four policies. In other words, by mixing the policies of adjusting the employment quota target/raising the quota ratio and implementing the double count/differentiating the amount of levy, we can achieve the goal of increasing jobs for the severely disabled and maintain equilibrium between incomings and outcomings.

과잉 PbO에 따른 Pb(Mg, Nb)O₃-PbTiO₃계 세라믹스의 압전특성

김규수,백동수,윤광희,이두희,박창엽,윤현상 연세대학교 산업기술연구소 1993 논문집 Vol.25 No.1

In this study, the dielectric, piezoelectric and structual properties of PMN-PT system ceramics were investigated with respect to the variation of PbO addition amount and sintering temperature. The specimen with 1.0wt% PbO addition exhibits relatively good sintering and piezoelectric properties, which has the density with 97.36%, the coupling constant(kp) with the value of 47.44% and the piezoelectric ?? with ?? at sintering temperature 1000℃ respectively.

RIPL peptide-conjugated nanostructured lipid carriers for enhanced intracellular drug delivery to hepsin-expressing cancer cells

Lee, Sang Gon,Kim, Chang Hyun,Sung, Si Woo,Lee, Eun Seok,Goh, Min Su,Yoon, Ho Yub,Kang, Myung Joo,Lee, Sangkil,Choi, Young Wook Dove Medical Press 2018 International journal of nanomedicine Vol.13 No.-

<P><B>Background</B></P><P>To facilitate selective and enhanced drug delivery to hepsin (Hpn)-expressing cancer cells, RIPL peptide (IPLVVPLRRRRRRRRC, 16-mer)-conjugated nanostructured lipid carriers (RIPL-NLCs) were developed.</P><P><B>Methods</B></P><P>NLCs were prepared using a solvent emulsification-evaporation method and the RIPL peptide was conjugated to the maleimide-derivatized NLCs via the thiol-maleimide reaction. Employing a fluorescent probe (DiI), in vitro target-selective intracellular uptake behaviors were observed using fluorescence microscopy and flow cytometry. Separately, docetaxel (DTX) was encapsulated by pre-loading technique, then cytotoxicity and drug release were evaluated. In vivo antitumor efficacy was investigated in BALB/c nude mice with SKOV3 cell tumors after intratumoral injections of different DTX formulations at a dose equivalent to 10 mg/kg DTX.</P><P><B>Results</B></P><P>RIPL-NLCs showed positively charged nanodispersion, whereas NLCs were negatively charged. DTX was successfully encapsulated with an encapsulation efficiency and drug loading capacity of 95–98% and 44-46 µg/mg, respectively. DTX release was diffusion-controlled, revealing the best fit to the Higuchi equation. Cellular uptake of DiI-loaded RIPL-NLCs was 8.3- and 6.2-fold higher than that of DiI-loaded NLCs, in Hpn(+) SKOV3 and LNCaP cells, respectively. The translocation of RIPL-NLCs into SKOV3 cells was time-dependent with internalization within 1 h and distribution throughout the cytoplasm after 2 h. DTX-loaded RIPL-NLCs (DTX-RIPL-NLCs) revealed dose-dependent in vitro cytotoxicity, while drug-free formulations were non-cytotoxic. In SKOV3-bearing xenograft mouse model, DTX-RIPL-NLCs significantly inhibited tumor growth: the inhibition ratios of the DTX solution-treated and DTX-RIPL-NLC-treated groups were 61.4% and 91.2%, respectively, compared to those of the saline-treated group (control).</P><P><B>Conclusion</B></P><P>RIPL-NLCs are good candidates for Hpn-selective drug targeting with a high loading capacity of hydrophobic drug molecules.</P>

CMOS-compatible Si metasurface at visible wavelengths prepared by low-temperature green laser annealing

Lee, Jeong Yub,Kim, Yongsung,Han, Seunghoon,Kim, Jaekwan,Yoon, Jae Woong,Lee, Ki Young,Song, Seok Ho,Yang, Kiyeon,Lee, Chang Seung IOP 2019 Nanotechnology Vol.30 No.4

<P>A low-temperature laser crystallization is newly devised for producing polycrystalline silicon (poly-Si) thin films of low-loss, low surface roughness enough for nanoscale patterning, applicable to practical Si metasurface elements on complementary metal-oxide semiconductor (CMOS) electronic architectures in visible lights. The method is based on dielectric encapsulation of an amorphous Si film and subsequent laser-induced local crystallization. Such poly-Si thin film yields order-of-magnitude smaller surface roughness and grain size than those obtained with the conventional laser annealing processes. The mechanism of the formation of small and uniform crystalline grains during solidification is studied to ensure the smooth surfaces enough for nanoscale patterning. By obtaining root mean square of surface roughness <2.49 nm and extinction coefficient <4.8?×?10<SUP>–2</SUP> at 550 nm, visible metasurface color-filter elements are experimentally demonstrated with the resonant transmission-peak efficiency approaching ∼85%. This low-loss poly-Si metasurface is favorably compatible with embedded CMOS electronic architectures in contrast to the conventional thermal annealing processes that often cause failure of electrical device functionalities due to delamination and material-property degradation problems. The proposed fabrication in this study provides a practical method for further development of various Si metasurfaces in the visible domain and their integration with CMOS electronic devices as well.</P>

The Effect of Trigger Point Injections on Pain in Patients with Advanced Cancer

Chang Yub Lee,Eeun Jung Kim,Dae Geun Hwang,Moon Yong Jung,Hyun Geun Cho 대한가정의학회 2019 Korean Journal of Family Medicine Vol.40 No.5

Background: It has been reported that in 62.5% of cases of incurable cancer pain, the complaint is due to myofascial pain syndrome. Trigger point injections using dibucaine hydrochloride help patients with such cancer pain. This study evaluated the efficacy of trigger point injections for alleviating pain in patients with advanced cancer. Methods: Twenty patients with advanced cancer who had a life expectancy of 6 months or less and had been diagnosed with myofascial pain syndrome were treated with trigger point injections. Prior to treatment, a Visual Analog Scale (VAS) was used to measure the resting pain level and discomfort upon application of pressure on the site of pain. These values were compared with last treatment measurements. Results: The mean pre-treatment VAS scores for pain at rest and upon application of pressure on the pain site were 7.3 and 9.0, respectively. These scores decreased significantly to 1.95 and 3.2, respectively, after the treatment (P<0.05). Conclusion: Trigger point injection is an alternative and effective pain control modality for advanced cancer patients with myofascial pain syndrome.

Dual Polarized MIMO System Using Bootstrapped Cross- Polarization Canceller

Sang-Yub Lee,Wan-Cheol Yang,Jeong-Suk Lee,Chang-Soo Yang,Hak-Sun Kim 한국통신학회 2005 한국통신학회 학술대회논문집 Vol.2005 No.6

Laboratory and radiological discrimination between tuberculous and malignant pleural effusions with high adenosine deaminase levels

( Jaehee Lee ),( Ji Eun Park ),( Sun Ha Choi ),( Hyewon Seo ),( Sang Yub Lee ),( Jae Kwang Lim ),( Seung Soo Yoo ),( Shin Yup Lee ),( Seung Ick Cha ),( Jae Yong Park ),( Chang Ho Kim ) 대한내과학회 2022 The Korean Journal of Internal Medicine Vol.37 No.1

Background/Aims: Pleural fluid adenosine deaminase (ADA) levels are useful in discriminating tuberculous pleural effusions (TPEs) from malignant pleural effusions (MPEs). However, some patients with MPE exhibit high-ADA levels, which may mimic TPEs. There is limited data regarding the differential diagnosis between high-ADA MPE and high-ADA TPE. This study aimed to identify the predictors for distinguishing high-ADA MPEs from high-ADA TPEs. Methods: Patients with TPE and MPE with pleural fluid ADA levels ≥ 40 IU/L were included in this study. Clinical, laboratory, and radiological data were compared between the two groups. Independent predictors and their diagnostic performance for high-ADA MPEs were evaluated using multivariate logistic regression analysis and receiver operating characteristic curve. Results: A total of 200 patients (high-ADA MPE, n = 30, and high-ADA TPE, n = 170) were retrospectively included. In the multivariate analysis, pleural fluid ADA, pleural fluid carcinoembryonic antigen (CEA), and pleural nodularity were independent discriminators between high-ADA MPE and high-ADA TPE groups. Using pleural ADA level of 40 to 56 IU/L (3 points), pleural CEA level ≥ 6 ng/mL (6 points), and presence of pleural nodularity (3 points) for predicting high-ADA MPEs, a sum score ≥ 6 points yielded a sensitivity of 90%, specificity of 96%, positive predictive value of 82%, negative predictive value of 98%, and area under the receiver operating characteristic curve of 0.965. Conclusions: A scoring system using three parameters may be helpful in guiding the differential diagnosis between high- ADA MPEs and high-ADA TPEs.

UWB Direct Sequences Chaotic Communications System

Sang-Yub Lee,Wan-Cheol Yang,Man-Seok Seo,Kwang-Du Lee,Sang-Gyu Park,Chang-Soo Yang 한국통신학회 2006 한국통신학회 학술대회논문집 Vol.2006 No.7