• Title/Summary/Keyword: DRE

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Removal of SF6 over Silicon Carbide with Aluminium Oxide by Microwave Irradiation (마이크로웨이브 조사에 따른 산화알루미늄이 함유된 실리콘카바이드의 SF6 제거)

  • Choi, Sung-Woo
    • Journal of Korean Society of Environmental Engineers
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    • v.35 no.4
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    • pp.240-246
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    • 2013
  • $SF_6$ is the most important greenhouse gas with the highest GWP (global warming potential). The $SF_6$ decomposition study was performed with silicon carbide with aluminium oxide by microwave irradiation. DRE (Decomposition and Removal Efficiencie) of $SF_6$ were evaluated by GC-TCD unit using 3,000 ppm $SF_6$ gas. DRE of $SF_6$ was increased by $Al_2O_3$ contents to 10~30 wt%, otherwise $Al_2O_3$ content of 40~50 wt% was decreased. DRE of $SF_6$ up to 99.99% have been achieved in SiC-$Al_2O_3$ (20 wt%) and SiC-$Al_2O_3$ (30 wt%) above $900^{\circ}C$. Also, the DRE of SiC-$Al_2O_3$ (30 wt%) at $700^{\circ}C$ showed 96.72%. In addition to consideration microwave input energy and $Al_2O_3$ content, SiC-$Al_2O_3$ (30 wt%) can be suggested the best material to control $SF_6$. The results of this study suggest it is important to control content of $Al_2O_3$ in SiC for decomposition of $SF_6$ with microwave energy.

Roles of Transcription Factor Binding Sites in the D-raf Promoter Region

  • Kwon, Eun-Jeong;Kim, Hyeong-In;Kim, In-Ju
    • Animal cells and systems
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    • v.2 no.1
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    • pp.117-122
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    • 1998
  • D-raf, a Drosophila homolog of the human c-raf-1, is known as a signal transducer in cell proliferation and differentiation. A previous study found that the D-raf gene expression is regulated by the DNA replication-related element (DRE)/DRE-binding factor (DREF) system. In this study, we found the sequences homologous to transcription factor C/EBP, MyoD, STAT and Myc recognition sites in the D-raf promoter. We have generated various base substitutional mutations in these recognition sites and subsequently examined their effects on D-raf promoter activity through transient CAT assays in Kc cells with reporter plasmids p5'-878DrafCAT carrying the mutations in these binding sites. Through gel mobility shift assay using nuclear extracts of Kc cells, we detected factors binding to these recognition sites. Our results show that transcription factor C/EBP, STAT and Myc binding sites in D-raf promoter region play a positive role in transcriptional regulation of the D-raf gene and the Myo D binding site plays a negative role.

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Epilepsy Surgery in Children versus Adults

  • Lee, Ki Hyeong;Lee, Yun-Jin;Seo, Joo Hee;Baumgartner, James E.;Westerveld, Michael
    • Journal of Korean Neurosurgical Society
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    • v.62 no.3
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    • pp.328-335
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    • 2019
  • Epilepsy is one of the most common chronic neurological disorder affecting 6-7 per 1000 worldwide. Nearly one-third of patients with newly diagnosed epilepsy continue to have recurrent seizures despite adequate trial of more than two anti-seizure drugs : drug-resistant epilepsy (DRE). Children with DRE often experience cognitive and psychosocial co-morbidities requiring more urgent and aggressive treatment than adults. Epilepsy surgery can result in seizure-freedom in approximately two-third of children with improvement in cognitive development and quality of life. Understanding fundamental differences in etiology, co-morbidity, and neural plasticity between children and adults is critical for appropriate selection of surgical candidates, appropriate presurgical evaluation and surgical approach, and improved overall outcome.

마이크로 블라스터를 이용한 태양전지용 재생웨이퍼 제작

  • Jeong, Dong-Geon;Gong, Dae-Yeong;Jo, Jun-Hwan;Jeon, Seong-Chan;Seo, Chang-Taek;Lee, Yun-Ho;Jo, Chan-Seop;Bae, Yeong-Ho;Lee, Jong-Hyeon
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.376-377
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    • 2011
  • 결정질 실리콘 태양전지 연구에 있어서 가장 중요한 부분은 재료의 저가화와 공정의 단순화에 의한 저가의 태양전지 셀 제작 부분과 고효율의 태양전지 셀 제작 부분이다. 본 논문에서는 마이크로 블라스터를 이용하여 폐 실리콘 웨이퍼를 태양전지용 재생웨이퍼를 제작함으로써 고효율을 가지는 단결정 실리콘 웨이퍼를 저 가격에 생산하기 위한 것이다. 특히 마이크로 블라스터를 이용하여 폐 실리콘 웨이퍼를 가공 할 때 표면에 생성되는 요철은 기존 태양전지 셀 제작에서 텍스쳐링 공정과 같은 표면 구조를 가지게 됨으로써 태양전지 셀에 제작 공정을 줄일 수 있는 효과도 가지게 된다. 마이크로 블라스터는 챔버 내에 압축된 공기나 가스에 의해 가속 된 미세 파우더들이 재료와 충돌하면서 재료에 충격을 주고 그 충격에 의해 물질이 식각되는 기계적 건식 식각 공정 기술이다. 이러한 물리적 충격을 이용하는 마이크로 블라스터 공정은 기존 재생웨이퍼 제작 공정 보다 낮은 재처리 비용으로 간단하게 태양전지용 재생웨이퍼를 제작 할 수 있다. 하지만 마이크로 블라스터를 이용하면 표면에 식각된 미세 파티클의 재흡착이 일어나게 되므로 이를 제거하기 위하여 DRE(damage remove etching) 공정이 필요하게 된다. 본 연구에서는 이방성, 등방성 식각 공정으로 태양전지용 재생웨이퍼를 제작하기 위해 가장 적합한 DRE 공정을 찾기 위해 등방성 식각은 RIE 식각으로, 그리고 이방성 식각은 TMAH 식각을 이용하였다. 마이크로 블라스터 공정 후 표면 반사율과 SEM 사진을 이용한 표면 요철 구조를 확인 하였고, DRE 공정 후 표면 반사율과 SEM 사진을 이용하여 표면 요철 구조를 확인 하였다. 각각의 lifetime을 측정하여 표면 식각으로 생성된 결함들을 분석하여 태양전지용 재생웨이퍼 제작에 가장 적합한 공정을 확인 하였다.

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Destruction and Removal of PCBs in Waste Transformer Oil by a Chemical Dechlorination Process

  • Ryoo, Keon-Sang;Byun, Sang-Hyuk;Choi, Jong-Ha;Hong, Yong-Pyo;Ryu, Young-Tae;Song, Jae-Seol;Lee, Dong-Suk;Lee, Hwa-Sung
    • Bulletin of the Korean Chemical Society
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    • v.28 no.4
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    • pp.520-528
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    • 2007
  • A practical and efficient disposal of PCBs (polychlorinated biphenyls) in waste transformer oil by a chemical dechlorination process has been reported. The transformer oil containing commercial PCB mixtures (Aroclor 1242, 1254 and 1260) was treated by the required amounts of PEG 600 (polyethylene glycol 600), potassium hydroxide (KOH) and aluminum (Al), along with different reaction temperatures and times. The reaction of PEG with PCBs under basic condition produces arylpolyglycols, the products of nucleophilic aromatic substitution. The relative efficiencies of PCB treatment process were assessed in terms of destruction and removal efficiency (DRE, %). Under the experimental conditions of PEG600/KOH/Al/100 oC/2hr, average DRE of PCBs was approximately 78%, showing completely removal of PCBs containing 7-9 chlorines on two rings of biphenyl which appear later than PCB no. 183 (2,2',3,4,4',5',6-heptaCB) in retention time of GC/ECD. However, when increasing the reaction temperature and time to 150 oC and 240 min, average DRE of PCBs including the most toxic PCBs (PCB no. 77, 105, 118, 123 and 169) in PCB family reached 99.99% or better, with the exception of PCB no. 5 and 8 (2,3-diCB and 2,4'-diCB). In studying the reaction of PEG with PCBs, it confirmed that the process led to less chlorinated PCBs through a stepwise process with the successive elimination of chlorines. The process also permits complete recovery of treated transformer oil through simple segregating procedures.

A study on improving the surface morphology of recycled wafer forsolar cells using micro_blaster (Micro blaster를 이용한 태양전지용 재생웨이퍼의 표면 개선에 관한 연구)

  • Lee, Youn-Ho;Jo, Jun-Hwan;Kim, Sang-Won;Kong, Dae-Young;Seo, Chang-Taeg;Cho, Chan-Seob;Lee, Jong-Hyun
    • Journal of Sensor Science and Technology
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    • v.19 no.4
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    • pp.291-296
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    • 2010
  • Recently, recycling method of waste wafer has been an area of solar cell to cut costs. Micro_blasting is one of the promising candidates for recycling of waste wafer due to their extremely simple and cost-effective process. In this paper, we attempt to explore the effect of micro_blasting and DRE(damage removal etching) process for solar cell. The optimal process conditions of micro_blasting are as follows: $10{\mu}m$ sized $Al_2O_3$ powder, jetting pressure of 400 kPa, and scan_speed of 30 cm/s. And the particles formed on micro_blasted wafer were removed by DRE precess which was performed by using HNA(HF/$HNO_3$/$CH_3COOH$) and TMAH(tetramethyl ammonium hydroxide). Structural analysis was done using a-step and the XRD patterns.

Suppression of CYP1A1 Expression by Naringenin in Murine Hepa-1c1c7 Cells

  • Kim, Ji-Young;Han, Eun-Hee;Shin, Dong-Weon;Jeong, Tae-Cheon;Lee, Eung-Seok;Woo, Eun-Rhan;Jeong, Hye-Gwang
    • Archives of Pharmacal Research
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    • v.27 no.8
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    • pp.857-862
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    • 2004
  • Naringenin, dietary flavonoid, is antioxidant constituents of many citrus fruits. In the present study, we investigated the effect of naringenin on 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-inducible CYP1 A 1 gene expression in mouse hepatoma Hepa-1c1c7 cells. Naringenin alone did not affect CYP1A1-specific 7-ethoxyresorufin O-deethylase (EROD) activity. In contrast, the TCDD-inducible EROD activities were markedly reduced upon concomitant treatment with TCDD and naringenin in a dose dependent manner. TCDD-induced CYP1A1 mRNA level was also markedly suppressed by naringenin. A transient transfection assay using dioxin-response element (DRE)-linked luciferase and electrophoretic mobility shift assay revealed that naringe-nin reduced transformation of the aryl hydrocarbons receptor(AhR) to a form capable of specif-ically binding to the DRE sequence in the promoter of the CYP1A1 gene. These results suggest the down regulation of the CYP1A1 gene expression by either naringenin in Hepa-1c1c7 cells might be antagonism of the DRE binding potential of nuclear AhR.

Impact of PSA and DRE on Histologic Findings at Prostate Biopsy in Turkish Men Over 75 Years of Age

  • Verim, Levent;Yildirim, Asif;Basok, Erem Kaan;Peltekoglu, Erol;Pelit, Eyup Sabri;Zemheri, Ebru;Tokuc, Resit
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.10
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    • pp.6085-6088
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    • 2013
  • Prostate specidic antigen (PSA) and digital rectal examination (DRE) are the known predictive factors for positive prostate biopsies differing according to the age, region and race. There have been only very limited studies about the impact of PSA on histological findings at prostate biopsy in Turkey. The aim of this study was to evaluate the impact of PSA and clinical stage on histologic findings of prostate biopsy in men older than 75 years of age as a first study in the Turkish population. A total of 1,645 consecutive prostate biopsies were included, with 194 men aged 75 or older. Cancer was identified in 104 patients (53.6%). Of the 104 positive biopsies, Gleason scores were less than 7 in 53 (49%) patients, 7 or greater in 51 (51%) patients. Positive prostate biopsies were significantly correlated with advanced age (p=0.0001), abnormal DRE (p=0.0001) and raised PSA (p=0.0001). The prostate volume was significantly correlated with advanced age especially in prostate cancer patients over 75 years, compared with those under 75 (p=0.0001). These results are useful for counseling men older than 75 years for prostate cancer detection. However, PCa screening decisions are currently based on urologist judgment and detection of latent asymptomatic disease is an important concern regarding costs, overdiagnosis, overtreatment and quality of life (QOL) for men aged 75 years and older. Healthy old patients with a long life expectancy need to be carefully evaluated for eligibility for PCa screening.

Effect of Reaction Gases on PFCs Treatment Using Arc Plasma Process (아크 플라즈마를 이용한 과불화합물 처리공정에서 반응가스에 의한 효과)

  • Park, Hyun-Woo;Choi, Sooseok;Park, Dong-Wha
    • Clean Technology
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    • v.19 no.2
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    • pp.113-120
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    • 2013
  • The treatment of chemically stable perflourocompounds (PFCs) requires a large amount of energy. An energy efficient arc plasma system has been developed to overcome such disadvantage. $CF_4$, $SF_6$ and $NF_3$ were injected into the plasma torch directly, and net plasma power was estimated from the measurement of thermal efficiency of the system. Effects of net plasma power, waste gas flow rate and additive gases on the destruction and removal efficiency (DRE) of PFCs were examined. The calculation of thermodynamic equilibrium composition was also conducted to compare with experimental results. The average thermal efficiency was ranged from 60 to 66% with increasing waste gas flow rate, while DRE of PFCs was decreased with increasing gas flow rate. On the other hand, DRE of each PFCs was increased with the increasing input power. Maximum DREs of $CF_4$, $SF_6$ and $NF_3$ were 4%, 15% and 90%, respectively, without reaction gas at the fixed input power and waste gas flow rate of 3 kW and 70 L/min. A rapid increase of DRE was found using hydrogen or oxygen additional gases. Hydrogen was more effective than oxygen to decompose PFCs and to control by-products. The major by-product in the arc plasma process with hydrogen was hydrofluoric acid that is easy to be removed by a wet scrubber. DREs of $CF_4$, $SF_6$ and $NF_3$ were 25%, 39% and 99%, respectively, using hydrogen additional gas at the waste gas flow rate of 100 L/min and the input power of 3 kW.