• Title/Summary/Keyword: self-limiting

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Recent Developments in H2 Production Photoelectrochemical Electrode Materials by Atomic Layer Deposition (원자층증착법을 이용한 수소 생성용 광전기화학 전극 소재 개발 동향)

  • Han, Jeong Hwan
    • Journal of Powder Materials
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    • v.25 no.1
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    • pp.60-68
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    • 2018
  • The design and fabrication of photoelectrochemical (PEC) electrodes for efficient water splitting is important for developing a sustainable hydrogen evolution system. Among various development approaches for PEC electrodes, the chemical vapor deposition method of atomic layer deposition (ALD), based on self-limiting surface reactions, has attracted attention because it allows precise thickness and composition control as well as conformal coating on various substrates. In this study, recent research progress in improving PEC performance using ALD coating methods is discussed, including 3D and heterojunction-structured PEC electrodes, ALD coatings of noble metals, and the use of sulfide materials as co-catalysts. The enhanced long-term stability of PEC cells by ALD-deposited protecting layers is also reviewed. ALD provides multiple routes to develop improved hydrogen evolution PEC cells.

Control of solid oxide fuel cell ceramic interfaces via atomic layer deposition (원자층 증착법을 통한 고체산화물 연료전지의 세라믹 인터페이스 제어)

  • Seo, Jongsu;Jung, WooChul;Kim, Jeong Hwan
    • Ceramist
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    • v.23 no.2
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    • pp.132-144
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    • 2020
  • Solid oxide fuel cell (SOFC) have attracted much attention due to clean, efficient and environmental-friendly generation of electricity for next-generation energy conversion devices. Recently, many studies have been reported on improving the performance of SOFC electrodes and electrolytes by applying atomic layer deposition (ALD) process, which has advantages of excellent film quality and conformality, and precise control of film thickness by utilizing its unique self-limiting surface reaction. ALD process with these advantages has been shown to provide functional ceramic interfaces for SOFC electrodes and electrolytes. In this article, recent examples of successful functionalization and stabilization on SOFC electrodes and electrolytes by the application of ALD process for realizing high performance SOFC cells are reported.

Epitaxial Growth of Polyurea Film by Molecular Layer Deposition

  • Choe, Seong-Eun;Gang, Eun-Ji;Lee, Jin-Seok
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.08a
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    • pp.264.2-264.2
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    • 2013
  • Molecular layer deposition (MLD) is sequential, self-limiting surface reaction to form conformal and ultrathin polymer film. This technique generally uses bifunctional precursors for stepwise sequential surface reaction and entirely organic polymer films. Also, in comparison with solution-based technique, because MLD is vapor-phase deposition based on ALD, it allows epitaxial growth of molecular layer on substrate and is especially good for surface reaction or coating of nanostructure such as nanopore, nanochannel, nanwire array and so on. In this study, polyurea film that consisted of phenylenediisocyanate and phenylenediamine was formed by MLD technique. In situ Fourier Transform Infrared (FTIR) measurement on high surface area SiO2 substrate was used to monitor the growth of polyurethane and polyurea film. Also, to investigate orientation of chemical bonding formed polymer film, plan-polarized grazing angle FTIR spectroscopy was used and it showed epitaxial growth and uniform orientation of chemical bones of polyurea films.

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Hybrid Organic-Inorganic Films Fabricated Using Atomic and Molecular Layer Deposition Techniques

  • George, Steven M.
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.08a
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    • pp.75.1-75.1
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    • 2013
  • Atomic layer deposition (ALD) and molecular layer deposition (MLD) are based on sequential, self-limiting surface reactions that produce atomic layer controlled and conformal thin film growth. ALD can deposit inorganic films and MLD can deposit films containing organics. ALD and MLD can be used together to fabricate a wide range of hybrid organic-inorganic alloy films. The relative fraction of inorganic and organic constituents can be defined by controlling the ratio of the ALD and MLD reaction cycles used to grow the film. These hybrid films can be tuned to obtain desirable mechanical, electrical and optical properties. This talk will focus on the growth and properties of metal alkoxide films grown using metal precursors and various organic alcohols that are known as "metalcones". The talk will highlight the tunable mechanical properties of alucone alloys grown using Al2O3 ALD and alucone MLD and the tunable electrical conductivity of zincone alloys grown using ZnO ALD and zincone MLD with DEZ and hydroquinone as the reactants.

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Aplastic Anemia Secondary to Methimazole-Case Report and Review- (Methimazole에 의한 재생불량성빈혈(再生不良性貧血) - 증례보고(症例報告) 및 문헌고찰(文獻考察))

  • Hong, Kee-Suck;Lee, Gwon-Jun;Kim, Byoung-Kook;Koh, Chang-Soon;Lee, Mun-Ho
    • The Korean Journal of Nuclear Medicine
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    • v.11 no.1
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    • pp.71-75
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    • 1977
  • A case is reported of aplastic anemia occuring during Methimazole therapy. Since this seems to be a kind of self-limiting disease having considerably rapid recovery, much more detailed supportive therapy is considered to be crucial rather than any other corticosteroid or the androgen therapy.

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$CO_2$Laser Aryepiglottoplasty for Treatment of Laryngomalacia in Patau Syndrome (PATAU 증후군에 동반된 후두연화증의 $CO_2$LASER를 이용한 수술치험례)

  • 송영호;이동엽;안회영;김영도
    • Korean Journal of Bronchoesophagology
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    • v.3 no.1
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    • pp.128-136
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    • 1997
  • Laryngomalacia is the most common cause of stridor in infant. It is a relatively benign self-limiting condition, but in severe cases, it results in obstructive sleep apnea, cor pulmonale , gastroesophageal reflux, failre to thrive, pectus excavatum, respiratory failure and death. When the airway obstruction related to laryngomalacia becomes significant, surgical correction of the underlying laryngeal deformity is indicated. Numerous reports provide evidence to support the trimming supraglottic soft tissue by using either conventional instruments or the surgical laser for treatment of severe laryngomalacia. Recently, authors experienced a case of laryngomalacia with Trisomy 13 (Patau syndrome) which had three times respiratory arrest and was treated with laser aryepiglottoplasty. We report this case with review of the literatures.

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Benign Acute Childhood Myositis: Perplexing Complication after Acute Viral Pharyngitis

  • Choi, Sung-Won;Ko, Hoon
    • Korean Journal of Family Medicine
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    • v.39 no.6
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    • pp.375-378
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    • 2018
  • Benign acute childhood myositis (BACM) is a rare transient condition that occurs in children during the early convalescent phase of a viral upper respiratory infection. BACM is self-limiting and characterized by sudden-onset bilateral calf pain that leads to difficulty in walking. We report a case of a 5-year-old boy with BACM who presented with acute-onset bilateral calf pain after a resolved episode of viral pharyngitis and subsequently refused to walk. With conservative treatment, the patient recovered completely after approximately 1 week. Although perplexing and challenging for clinicians unfamiliar with BACM, awareness of this rare clinical condition is essential to preventing unnecessary investigations and reassuring the patient and parents of its excellent prognosis.

Intravesical bacillus Calmette-Guérin-induced myopathy presenting as rhabdomyolysis: a case report

  • Chae Hun Lee;Byeong Joo Choi;Jung Hun Kim;Tae Woong Yang;Gi Jeong Kim;Ha Young Shin;Se Hoon Kim;Seung Woo Kim
    • Journal of Yeungnam Medical Science
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    • v.40 no.4
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    • pp.430-434
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    • 2023
  • Intravesical bacillus Calmette-Guérin (BCG) instillation is an adjuvant treatment for non-muscle-invasive urinary bladder cancer. Although most complications associated with BCG immunotherapy are mild and self-limiting, rare albeit serious complications have been reported. Only a few cases of BCG-related rhabdomyolysis have been reported. In this study, we present the case of a 72-year-old woman who developed severe weakness and hyperCKemia following intravesical BCG instillation. A muscle biopsy was performed, and a diagnosis of drug-induced myopathy was made.

Spontaneous Pneumomediastinum: Clinical Experience of 24 Patients in Two Medical Center (자연성 종격동 기종: 두 병원에서의 임상 경험 24예)

  • Moon, Hyeon-Jong
    • Journal of Chest Surgery
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    • v.43 no.6
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    • pp.663-668
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    • 2010
  • Background: Spontaneous pneumomediastinum is an uncommon disorder with few cases reported. It usually occurs in young males and has benign self-limiting course without any apparent concomitant factor. It is seen after intrathoracic pressure changes leading to alveolar rupture. The clinical experiences of two medical centers were reviewed to aid in optimal management. Material and Method: Retrospective review between March 2003 and August 2010 with spontaneous pneumomediastinum patients was performed. Result: 24 patients were identified with a diagnosis of spontaneous pneumomediastinum. These 24 patients were comprised of 18 men and 6 women with mean age 18.9 years (range 10 ~ 33). The major initial complaints were chest pain (79.2%), throat pain (62.5%), and subcutaneous emphysema (41.7%). The triggering events were exercise (16.7%), coughing (12.5%) and vomiting (12.5%). No apparent triggering event was noted in 54.2% of patients. In all cases, chest radiograph and computed tomography was done. Diagnostic computed tomography was required in 25%. White blood cell counts and C-reactive protein (CRP) were checked, and their initial mean values were $9,790{\pm}3,240/{\mu}L$ Land $1.31{\pm}1.71mg/dL$, final mean values were $5,440{\pm}1,665/{\mu}L$ Land $0.72{\pm}0.73mg/dL$, respectively. 23 patients were admitted (average $5.0{\pm}1.8$) and the symptoms were self-limiting in all cases without complications. Conclusion: Spontaneous pneumomediastinum is a benign condition with mild inflammatory signs that often presents with chest or throat pain. Secondary causes must be ruled out to avoid an unfavorable outcome with less invasive study. Because of very rare complications and recurrence, outpatient basis and shortened hospitalization may be feasible.

Deposition and Characteristics of TiN Thin Films by Atomic Layer Epitaxy (ALE 법에 의한 TiN 박막의 증착 및 특성)

  • Kim, Dong-Jin;Jung, Young-Bae;Lee, Myung-Bok;Lee, Jung-Hee;Lee, Yong-Hyun;Hahm, Sung-Ho;Lee, Jong-Hwa
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.37 no.6
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    • pp.43-49
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    • 2000
  • The TiN thin films were deposited by ALE(atomic layer epitaxy) on (100) silicon substrate. The TiN thin films were characterized by means of XRD, 4-point probe, AFM, AES and SEM. TEMAT(terakis(ethyl methy lamino)titanium) and $NH_3$ were injected into the reactor in sequence of TEMAT-$N_2-NH_3-N_2$ to ensure a saturated surface reaction. As a result, the depostion rate of the TiN film was controlled by self-limiting growth mechanism at temperature range form 150 to 220 $^{\circ}C$. Deposited TiN films, all of which show amorphous structure, had a fixed deposition rate of 4.5 ${\AA}$/cycle. The resistivity of 210 ~ 230 ${\mu}{\Omega}{\cdot}$cm and the surface r.m.s. roughness of 7.9 ~ 9.3 ${\AA}$ were measured. When TiN film of 2000 ${\AA}$ were deposited, a excellent step coverage were observed in a trench structure of 0.43${\mu}m$ contacts with 6:1 aspect ratio.

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