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검색결과 722건 처리시간 0.021초

수소 연료전지 추진 선박 적용을 위한 메탄올 수증기 개질 시스템 최적 운전점 연구 (A Study on Optimal Operation of Methanol Steam Reforming System for Hydrogen Fuel Cell Propulsion Ships)

  • 조희주;현수빈;정승교;지현진;최정호
    • 한국수소및신에너지학회논문집
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    • 제33권6호
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    • pp.733-742
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    • 2022
  • Hydrogen fuel cell propulsion ships are emerging to respond to the recently strengthened carbon emission regulations in the international shipping sector. Methanol can be stored in a liquid state at normal pressure and temperature, and has the advantage of lower reforming temperature compared to other fuels. In this study, the optimal operating point of the methanol steam reforming system was derived by changing the Steam Carbon Ratio (SCR) from 0.10 to 3.00. Results showed that In terms of methanol conversion rate and hydrogen yield, the larger the SCR is the better, but in terms of system efficiency, it is most advantageous to operate at SCR 0.70 in Pressure Swing Adsorption (PSA) mode and SCR 0.80 in Pd membrane mode. Through this study, it was found that the optimal SCR in the reformer and the entire system including the reformer may be different, which indicates that the optimum operating point may be different depending on the change of the system configuration.

블랙 파우더 침출용액을 이용한 재활용 리튬이온전지의 양극 활물질 공침법에 대한 연구 (A Study on Co-precipitation of Positive Electrode Active Material for Recycled Lithium-ion Batteries Using Black Powder Leaching Solution)

  • 이재근;이재경;권성기;박계춘
    • 한국수소및신에너지학회논문집
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    • 제35권3호
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    • pp.336-344
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    • 2024
  • In this study, a Ni0.9Co0.05Mn0.05(OH)2 precursor used as an anode active material using a black powder leaching solution of a recycled lithium ion battery was prepared through coprecipitation synthesis with co-precipitation time, NH4OH concentration, pH, and stirring time as variables. The characteristics of the prepared powder were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), particle size analysis (PSA), and inductively coupled plasma optical emission spectroscopy (ICP-OES). It was confirmed that the single crystal thickness of the LiNi1-x-yCoxMnyO2 (NCM) precursor changes depending on the NH4OH concentration and reaction pH value, and thicker single crystals are formed at 2 M NH4OH compared to 1 M and at pH 10.8-11.8 compared to pH 11.8-12.0. NCM precursor particles increased with coprecipitation time, and it was confirmed that the 72 hours NCM precursor had the largest particle size. Through ICP-OES analysis, it was confirmed that the NCM precursor was synthesized with the target composition of Ni2+:Co2+:Mn2+=90:5:5.

$Mg_2NiH_x$ 수소저장합금의 미세결정구조 및 수소화 특성평가 (Evaluations of Microstructure and Hydrogenation Properties on $Mg_2NiH_x$)

  • 석송;신경;권순용;어순철;이영근;홍태환
    • 한국수소및신에너지학회논문집
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    • 제16권3호
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    • pp.238-243
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    • 2005
  • Mg and Mg-based alloys are most important hydrogen storage materials. It is a lightweight and low-cost materials with high hydrogen storage capacity. However, the formation of hydride at high temperature, the deterioration effect, the hydriding and dehydriding kinetics are bad factor for application. In this study, Mg and Ni have been produced by hydrogen induced mechanical alloying(HIMA) process. The raw materials, Mg(purity 99.9%) chip and Ni(purity 99.95%) chip was prepared by using a planetary ball mill apparatus(FRITSCH pulverisette 5). The balls to chips mass ratio(BCR) are 30:1. The hydrogen pressure induced 2.0MPa and milling times were 12, 24, 48, 72, 96 hours with a rotating speed of 200rpm. X-ray diffraction(XRD) analysis was made to characterize the crystallite size and misfit strain. The crystallite size measured by laser particle size analysis(PSA). Microstructure changes were investigated by scanning electron microscopy(SEM) and the transmission electron microscopy(TEM). The hydrogen storage properties were evaluated by using an Sivert's type automatic pressure-composition-therm(PCT) apparatus.

SPECT 심근영상의 영상분할을 이용한 3차원 재구성 (3D Reconstruction Using Segmentation of Myocardial SPECT Images)

  • 정재은;이상복
    • 한국방사선학회논문지
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    • 제3권2호
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    • pp.5-10
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    • 2009
  • 심근영상의 SPECT(Single Photon Emission Computed tomography)검사는 감마선을 방출하는 방사성의약품을 환자에게 정맥주사한 후 이 의약품이 심장에 고루 퍼지면 관심부위를 촬영하여 질병으로 인한 변화를 컴퓨터를 이용하여 진단하는 검사법이다. 기능적인 정보를 담고 있는 심근관류 영상은 비침습적인 심근질환 검사에 유용한 방법이지만, 물리적 인자들에 의해 잡음과 낮은 해상도는 판도하는데 어려움을 주게 된다. 본 논문은 심근영상을 레벨 셋 알고리즘을 이용하여 영상을 분할하고 분할된 영역을 3차원으로 구현하여 판독에 도움을 주는 방안을 제안하였다. 판독의 어려움을 해결하기 위하여 레벨 셋을 이용하여 관심부위인 좌심실 영역을 분할하였고 분할된 영역을 3차원영상으로 모델링하였다.

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SPECT 심근영상의 영상분할을 이용한 3차원 재구성 (3D Reconstruction Using Segmentation of Myocardial SPECT)

  • 정재은;이준행;최석윤;이상복
    • 한국산학기술학회논문지
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    • 제11권6호
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    • pp.2240-2245
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    • 2010
  • 심근영상의 SPECT(Single Photon Emission Computed tomography)검사는 감마선을 방출하는 방사성의약품을 환자에게 정맥주사한 후 이 의약품이 심장에 고루 퍼지면 관심부위를 촬영하여 질병으로 인한 변화를 컴퓨터를 이용하여 진단하는 검사법이다. 기능적인 정보를 담고 있는 심근관류 영상은 비침습적인 심근질환 검사에 유용한 방법이지만, 물리적 인자들에 의해 잡음과 낮은 해상도는 판도하는데 어려움을 주게 된다. 본 논문은 심근영상을 레벨 셋 알고리즘을 이용하여 영상을 분할하고 분할된 영역을 3차원으로 구현하여 판독에 도움을 주는 방안을 제안하였다. 판독의 어려움을 해결하기 위하여 레벨 셋을 이용하여 관심부위인 좌심실 영역을 분할하였고 분할된 영역을 3차원영상으로 모델링 하였다.

건설용 재료로서 상동광산광미의 활용성 검토 (Availability Review of Tailings from the Sangdong Tungsten Mine as a Material for Construction)

  • 김용직;김영진;최연왕;김상철
    • 한국건설순환자원학회논문집
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    • 제1권3호
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    • pp.204-210
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    • 2013
  • 상동지역 중석광 광미의 품질 특성을 파악하기 위해 XRD 및 PSA를 사용하여 광물학적인 특성을 검토하였다. XRD분석 결과 상동지역 중석광 광미내에는 석영(quartz), 녹니석(chlorite), 회장석(anorthite) 그리고 코디에라이트(cordierite) 등이 함유되어 있는 것으로 파악되었다. 또한, 상동지역 중석광 광미의 용출 특성을 파악하기 위해 광미를 혼합한 모르터를 제작하여 KSLT의 규정에 의해 실험한 결과 폐기물 관리법 시행규칙에 제시된 유해물질 함유 기준값 보다 낮은 결과를 나타내었으며, 특히, 고루슬래그 미분말의 혼합률이 증가할수록 중금속의 농도는 감소함을 알 수 있다.

Resveratrol Inhibits IL-6-Induced Transcriptional Activity of AR and STAT3 in Human Prostate Cancer LNCaP-FGC Cells

  • Lee, Mee-Hyun;Kundu, Joydeb Kumar;Keum, Young-Sam;Cho, Yong-Yeon;Surh, Young-Joon;Choi, Bu Young
    • Biomolecules & Therapeutics
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    • 제22권5호
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    • pp.426-430
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    • 2014
  • Prostate cancer is the most frequently diagnosed cancer. Although prostate tumors respond to androgen ablation therapy at an early stage, they often acquire the potential of androgen-independent growth. Elevated transcriptional activity of androgen receptor (AR) and/or signal transducer and activator of transcription-3 (STAT3) contributes to the proliferation of prostate cancer cells. In the present study, we examined the effect of resveratrol, a phytoalexin present in grapes, on the reporter gene activity of AR and STAT3 in human prostate cancer (LNCaP-FGC) cells stimulated with interleukin-6 (IL-6) and/or dihydrotestosterone (DHT). Our study revealed that resveratrol suppressed the growth of LNCaP-FGC cells in a time- and concentration-dependent manner. Whereas the AR transcriptional activity was induced by treatment with either IL-6 or DHT, the STAT3 transcriptional activity was induced only by treatment with IL-6 but not with DHT. Resveratrol significantly attenuated IL-6-induced STAT3 transcriptional activity, and DHT- or IL-6-induced AR transcriptional activity. Treatment of cells with DHT plus IL-6 significantly increased the AR transcriptional activity as compared to DHT or IL-6 treatment alone and resveratrol markedly diminished DHT plus IL-6-induced AR transcriptional activity. Furthermore, the production of prostate-specific antigen (PSA) was decreased by resveratrol in the DHT-, IL-6- or DHT plus IL-6-treated LNCaP-FGC cells. Taken together, the inhibitory effects of resveratrol on IL-6- and/or DHT-induced AR transcriptional activity in LNCaP prostate cancer cells are partly mediated through the suppression of STAT3 reporter gene activity, suggesting that resveratrol may be a promising therapeutic choice for the treatment of prostate cancer.

TMPRSS2:ETS Fusions and Clinicopathologic Characteristics of Prostate Cancer Patients from Eastern China

  • Dong, Jun;Xiao, Li;Sheng, Lu;Xu, Jun;Sun, Zhong-Quan
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권7호
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    • pp.3099-3103
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    • 2014
  • TMPRSS2:ERG gene fusions in prostate cancer have a dominant prevalence of approximately 50.0%, but infomration is limited on differences among ethnic and geographical groups. Some studies focusing on Japanese and Korean patients reported a lower incidence. Investigations concerning Chinese revealed controversial results. We evaluated TMPRSS2:ERG, TMPRSS2:ETV1 and TMPRSS2:ETV4 fusions in more than 100 Eastern Chinese prostate cancer patients. Paraffin blocks of needle biopsy and radical prostatectomy were collected from 91 and 18 patients respectively. All patients' clinicopathologic factors were gathered. TMPRSS2:ERG, TMPRSS2:ETV1 and TMPRSS2:ETV4 fusions were tested by multi-probe fluorescence in situ hybridization (FISH) assay. TMPRSS2:ERG fusions was present in 14.3% biopsy specimens and 11.1% radical prostatectomy patients. Neither TMPRSS2:ETV1 nor TMPRSS2:ETV4 fusion was found in any case. Altogether, 13 (86.7%) TMPRSS2:ERG fusion positive cases possessed deletion pattern and 7 (46.6%) and insertion pattern. Some 5 cases had both deletion and insertion patterns. While 38.5% (5/13) patients with deletion pattern had distant metastasis, except for one metastatic case harboring both deletion and insertion, there were no patients with insertion pattern accompanied with metastasis. There were no differences between fusion positive and negative cases in the distribution of age, PSA, Gleason score and TNM stage. Eastern Chinese prostate cancer patients have a significantly low incidence of TMPRSS2:ERG fusion. They also lack TMPRSS2:ETV1 and TMPRSS2:ETV4 fusion. There are more deletion pattern than insertion pattern in TMPRSS2:ERG positive cases. Fusion positive and negative patients have no clinicopathologic factor differences.

내측개방형 근위경골절골술의 경골절단면 및 경골개방축의 설정에 따른 영향 (Effect of Tibial Cut Planes and Hinge Axes on Medial Opening Wedge High Tibial Osteotomy)

  • 박병건;이호상;김재정;김철웅
    • 대한기계학회논문집A
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    • 제35권8호
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    • pp.835-846
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    • 2011
  • 최근 보편화 되고 있는 내측개방형절골술 시에 의도하지 않은 경골후방경사각의 변화로 인한 문제점들이 보고되었다. 이를 해결하기 위해 많은 연구들이 진행되어 왔지만 환자의 다양한 경골의 형상 및 절단면의 기울기에 적용될 수 있는 일반적 해석 모델은 아직 제안되지 못하고 있다. 따라서 본 논문에서는 일반적인 케이스에 적용할 수 있는 근위경골절골술의 해석 모델을 제안한다. 이를 위해 내반교정각만을 조정할 수 있는 가상경골축을 정의하고, 이를 통해 절단면과 경골개방축이 내반교정각에 주는 영향을 나타내는 수학적 모델을 제안하고, 기존의 수술적인 변수들간의 상관관계를 명확히 나타내었다. 또한 내반교정각과 경골후방경사각에 추가로, 새로운 각도인 경골뒤틀림각의 존재를 도입함으로써 수술 시 발생하는 모든 기하학적 변수들간의 관계를 완성된 형태로 표현하였다.

Role of Hyperinsulinemia in Increased Risk of Prostate Cancer: A Case Control Study from Kathmandu Valley

  • Pandeya, Dipendra Raj;Mittal, Ankush;Sathian, Brijesh;Bhatta, Bibek
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권2호
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    • pp.1031-1033
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    • 2014
  • Aim: To investigate the effect of hyperglycemia and hyperinsulinemia on prostate cancer risk. Materials and Methods: This hospital based study was carried out using data retrieved from the register maintained in the Department of Biochemistry of a tertiary care hospital of Kathmandu, Nepal between $31^{st}$ December, 2011 and $31^{st}$ October, 2013. The variables collected were age, serum cholesterol, serum calcium, PSA, fasting blood glucose, serum insulin. Analysis was performed by descriptive statistics and testing of hypothesis using Excel 2003, R 2.8.0, Statistical Package for the Social Sciences (SPSS) for Windows Version 16.0 (SPSS Inc; Chicago, IL, USA) and the EPI Info 3.5.1 Windows Version. Results: Of the total 125 subjects enrolled in our present study, 25 cases were of PCa and 100 were healthy controls. The mean value of fasting plasma glucose was 95.5 mg/dl in cases of prostatic carcinoma and the mean value of fasting plasma insulin was $5.78{\mu}U/ml$ (p value: 0.0001*). The fasting insulin levels ${\mu}U/ml$ were categorized into the different ranges starting from ${\leq}2.75$, >2.75 to ${\leq}4.10$, >4.10 to ${\leq}6.10$, > $6.10{\mu}U/ml$. The maximum number of cases of prostatic carcinoma of fasting insulin levels falls in range of > $6.10{\mu}U/ml$. The highest insulin levels (> $6.10{\mu}U/ml$) were seen to be associated with an 2.55 fold risk of prostatic carcinoma when compared with fasting insulin levels of (< $2.75{\mu}U/ml$). Conclusions: Elevated fasting levels of serum insulin appear to be associated with a higher risk of prostate cancer.