• 제목/요약/키워드: Primary Si

검색결과 534건 처리시간 0.022초

Octamethylcyclotetrasiloxane를 이용한 광섬유 클래드 프리폼 형성 (Formation of Optical Fiber Preform Using Octamethylcyclotetrasiloxane)

  • 최진석;이태균;박성규;이가형;전구식;안성진
    • 한국재료학회지
    • /
    • 제28권1호
    • /
    • pp.6-11
    • /
    • 2018
  • There are various manufacturing processes for pure $SiO_2$ that is used as abrasives, chemicals, filters, and glasses, and in metallurgy and optical industries. In the optical fiber industry, to produce $SiO_2$ preform, $SiCl_4$ is utilized as a raw material. However, the combustion reaction of $SiCl_4$ has caused critical environmental issues, such as ozone deficiency by chlorine compounds, the greenhouse effect by carbon dioxide and corrosive gas such as hydrochloric acid. Thus, finding an alternative source that does not have those environmental issues is important for the future. Octamethylcyclotetrasiloxane (OMCTS or D4) as a chlorine free source is recently promising candidate for the $SiO_2$ preform formation. In this study, we first conducted a vaporizer design to vaporize the OMCTS. The vaporizer for the OMCTS vaporization was produced on the basis of the results of the vaporizer design. The size of the primary particle of the $SiO_2$ formed by OMCTS was less than 100 nm. X-ray diffraction patterns of the $SiO_2$ indicated an amorphous phase. Fourier-transform infrared spectroscopy analysis revealed the Si-O-Si bond without the -OH group.

Characteristic X-ray Spectrum Analysis of Micro-Sized SiC

  • Miyoshi, Noriko;Mao, Weiji;Era, Hidenori;Shimozaki, Toshitada;Shinozaki, Nobuya
    • Applied Microscopy
    • /
    • 제46권1호
    • /
    • pp.27-31
    • /
    • 2016
  • It has been investigated what kind of characteristic X-ray in electron probe micro-analyzer (EPMA) is effective for the determination of compounds of Si series materials. After comparing the characteristic X-rays among the primary and secondary lines in $K_{\alpha}$ and $K_{\beta}$ obtained from the Si series standard samples, it was found that the secondary line of $K_{\alpha}$ exhibited the most informative spectrum although the intensity was considerably weak. As a result of analyzing the spectrum shapes of the Si series standard samples, the spectrum shape of the secondary line of $K_{\alpha}$ for SiC was different from those for other Si compounds. To grasp the characteristics of the shape, a line was perpendicularly drawn from the peak top to base line in order to divide a spectrum into two areas. The area ratio of right to left was defined to call as the asymmetry index here. As a result, the asymmetry index value of the SiC was greater than one, while those of other Si compounds were less than one. It was found from the EPMA analysis that identification of SiC became successful to distinguish from other Si compounds and this method was applicable for micro-sized compounds in a practical composite material.

Pulsed Radiofrequency Application for the Treatment of Pain Secondary to Sacroiliac Joint Metastases

  • Yi, Yu Ri;Lee, Na Rea;Kwon, Young Suk;Jang, Ji Su;Lim, So Young
    • The Korean Journal of Pain
    • /
    • 제29권1호
    • /
    • pp.53-56
    • /
    • 2016
  • Sacroiliac (SI) joint pain can result from degeneration, infection, malignancy, and trauma. Patients with metastatic bone pain who do not respond to conventional treatment may need more aggressive neuroinvasive approaches. Recently, pulsed radiofrequency (PRF) neuromodulation has emerged as a promising treatment alternative for refractory cases of SI joint pain. Nevertheless, there is no report on the treatment of pain arising from SI joint metastases with PRF. We are reporting about a 63-year-old woman suffering from buttock pain due to breast cancer metastases in the SI joint. We treated this patient with PRF neuromodulation of the L4-S3 primary dorsal rami and lateral branches using a rotating curved needle technique. The patient tolerated the procedures well, without any complications. She experienced about 70% reduction in pain, and pain relief was sustained for 10 months. This result suggests that PRF neuromodulation is a safe, effective treatment for pain from SI joint metastases.

Effect of MUC1 siRNA on Drug Resistance of Gastric Cancer Cells to Trastuzumab

  • Deng, Min;Jing, Da-Dao;Meng, Xiang-Jun
    • Asian Pacific Journal of Cancer Prevention
    • /
    • 제14권1호
    • /
    • pp.127-131
    • /
    • 2013
  • Trastuzumab is the first molecular targeting drug to increase the overall survival rate in advanced gastric cancer. However, it has also been found that a high intrinsic or primary trastuzumab resistance exists in some proportion of gastric cancer patients. In order to explore the mechanism of resistance to trastuzumab, firstly we investigated the expression of MUC1 (membrane-type mucin 1) in gastric cancer cells and its relationship with drug-resistance. Then using gene-silencing, we transfected a siRNA of MUC1 into drug-resistant cells. The results showed the MKN45 gastric cell line to be resistant to trastuzumab, mRNA and protein expression of MUC1 being significantly upregulated. After transfection of MUC1 siRNA, protein expression of MUC1 in MKN45cells was significantly reduced. Compared with the junk transfection and blank control groups, the sensitivity to trastuzumab under MUC1 siRNA conditions was significantly increased. These results imply that HER2-positive gastric cancer cell MKN45 is resistant to trastuzumab and this resistance can be cancelled by silencing expression of the MUC1 gene.

반고상 온도구역에서 등온유지한 Al-Si, Al-Cu 및 Mg-Al합금의 고상형상 및 조직의 변화 (Variation of Morphology of Solid Particles and Microstructure in Al-Si, Al-Cu and Mg-Al Alloys During Isothermal Heat-Treatment at Semi-Solid Temperatures)

  • 정운재;김기태;홍준표
    • 한국주조공학회지
    • /
    • 제16권6호
    • /
    • pp.556-564
    • /
    • 1996
  • Variation of shape and size of solid particles and solute redistribution in Mg-9wt.%Al, AI-4.5wt.% Cu, and AI-7wt.%Si alloys were investigated when they were heated to semi-solid temperatures and held without stirring. In the case of Mg-9wt.% Al and Al-4.5wt.%Cu alloys, the polygonal shaped solid particles were agglomerated with non-uniform distribution, and there were no disappearance of the solid/solid boundary until the end of melting. But in the case of an Al-7wt.%Si alloys, two or three spherical shaped particles were coalesced or separated individually, and the coalesced particles had no solid/solid interface on the contrary to the prevous case. The maximum size of solid particles during isothermal heating at high temperature was smaller than that at lower temperature, but the time required to reach the maximum size at high temperature was shorter than that at lower temperature. The concentrations of main solute atom whose distribution coefficient is lower than 1, decreased in the primary solid particles as the liquid fraction increased, and the gradient of solute concentration was steeper in Mg-9wt.%Al alloy and Al-4.5wt.%Cu alloy than that of Al-7wt.%Si alloy.

  • PDF

Cu와 Si 첨가에 의한 Al-Sn 합금의 미세조직 제어 (Microstructural Control of Al-Sn Alloy with Addition of Cu and Si)

  • 손광석;박태은;김진수;강성민;김태환;김동규
    • 대한금속재료학회지
    • /
    • 제48권3호
    • /
    • pp.248-255
    • /
    • 2010
  • The effect of various alloying elements and melt treatment on the microstructural control of Al-Sn metallic bearing alloy was investigated. The thickness of tin film crystallized around primary aluminum decreased with the addition of 5% Cu in Al-Sn alloy, with tin particles being reduced in size by intervening the Ostwald ripening. With the addition of Si in Al-10%Sn alloy, the tin particles were crystallized with eutectic silicon, resulting in uniform distribution of tin particles. With the addition of Cu and Si in Al-Sn alloy, both the tensile strength and yield strength increased, with the increasing rate of yield strength being less than that of tensile strength. Although the Al-10%Sn-7%Si alloy has similar tensile strength compared with Al-10%Sn-5%Cu, the former showed superior abrasion resistance, resulting from preventing the tin particles from movement to the abrasion surface.

Al-Si 합금의 소성변형 거동 (Plastic Deformation Behavior of Al-Si Alloy)

  • 권용남;김상우;이영선;이정환
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 2005년도 추계학술대회 논문집
    • /
    • pp.130-133
    • /
    • 2005
  • The effect of microstructural characteristics of A356 alloys on tensile behavior was studied ill the present study. To authors' knowledge, the microstructural effect on mechanical properties of A356 alloy has not been well understood even though this alloy system is one of the most widely used alloys for the industrial purpose. Specially, quantitative relationship between properties like ductility and fracture toughness with microstructural features is lacking. In the present study, three processing routes was used to fabricate samples with different microstructures like size and distribution of primary alpha and eutectic phases. Also, compressive deformation was used to close casting porosity for the cast samples. Tensile behavior was examine and discussed in terms of microstructural aspects.

  • PDF

Effect of Alternating Magnetic Field on Ion Activation in Low Temperature Polycrystalline Silicon Technology

  • Hwang, Jin Ha;Lim, Tae Hyung
    • 반도체디스플레이기술학회지
    • /
    • 제3권1호
    • /
    • pp.35-39
    • /
    • 2004
  • Statistical design of experiments was successfully employed to investigate the effect of alternating magnetic field on activation of polycrystalline Si (p-Si) doped as n-type using $\textrm{PH}_3$, by full factorial design of three factors with two levels. In this design, the input variables are graphite size, alternating current, and activation time. The output parameter, sheet resistance, is analyzed in terms of the primary effects and multi-factor interactions. Notably, the three-factor interaction is calculated to be a dominant interaction. The interaction between graphite size and activation time and the main effect of current are important effects compared to the other variables and relevant interactions. Alternating magnetic flux activation is proved a significantly beneficial processing technique.

  • PDF

Chemoselective Iodination of Alcohols with CeCl3·7H2O/NaI over SiO2 under Microwave Irradiation

  • Hosseinzadeh, Rahman;Tajbakhsh, Mahmood;Lasemi, Zahra;Sharifi, Ali
    • Bulletin of the Korean Chemical Society
    • /
    • 제25권8호
    • /
    • pp.1143-1146
    • /
    • 2004
  • A simple and effective procedure for conversion of primary, secondary, allylic and benzylic alcohols into the corresponding iodides is described using $CeCl_3{\cdot}7H_2O/NaI\;over\;SiO_2$ under microwave irradiation. Benzylic alcohols are selectively converted in the presence of saturated alcohols into their corresponding benzylic iodides under these conditions.