• Title/Summary/Keyword: Yttrium aluminum garnet

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Influence of Liquid-Phase Amount on the Microstructure and Phase Transformation of Liquid-phase Sintered Silicon Carbide (액상량이 탄화규소 소결체의 미세구조 및 상변태에 미치는 영향)

  • 이종국;강현희;박종곤;이은구
    • Journal of the Korean Ceramic Society
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    • v.35 no.4
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    • pp.413-419
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    • 1998
  • ${\beta}$-silicon carbides with yttrium aluminum garnet of 2,5,10 mol% were prepared by a liquid--phase sint-ering and the microstructural evolution and phase transformation were investigated during sintering as functions of liquid-phase amount and sintering time. The rate of grain growth decreases with the addition of the amount of yttrium aluminum garnet (YAG) in the SiC starting powder however the apparent density and the aspect ratio of grains in sintered body increase. The phase transformation from ${\beta}$-SiC to ${\alpha}$-SiC were dependent on the liquid-phase amount and sintering time.

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Synthesis of Ceramic Protective Coatings for Chemical Plant Parts Operated in Hi-temperature and Corrosive/Erosive Environment

  • Son, M.C.;Park, J.R.;Hong, K.T.;Seok, H.K.
    • Corrosion Science and Technology
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    • v.4 no.1
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    • pp.33-38
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    • 2005
  • Some feasibility studies are conducted to produce an advanced ceramic coating, which reveals superior chemical and mechanical strength, on metal base structure used in chemical plant. This advanced coating on metallic frame can replace ceramic delivery pipe and reaction chamber used in chemical plant, which are operated in hi-temperature and corrosive/erosive environment. An dual spraying is adopted to reduce the residual stress in order to increase the coating thickness and the residual stress is estimated by in-situ manner. Then new methodology is tried to form special coating of yttrium aluminum garnet(YAG), which reveals hi-strength and low-creep rates at hi-temperature, superior anti-corrosion property, hi-stability against Alkali-Vapor corrosion, and so on, on iron base structure. To verify the formation of YAG during thermal spraying, XRD(X ray diffraction) technique was used.

Post-acne Erythema Successfully Treated with 595-nm Picosecond-domain Neodymium:Yttrium-aluminum-garnet Laser

  • Kim, Jae-Hong;Choe, Sung Jay;Kim, Tae-Gyun
    • Medical Lasers
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    • v.9 no.1
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    • pp.84-87
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    • 2020
  • Post-acne erythema (PAE) is one of the major problems during or after treatment of acne vulgaris with any modality. A variety of therapeutic options have been described with various clinical outcomes and side effects. We report here on treating a patient with PAE using 595-nm picosecond-domain neodymium:yttrium-aluminum-garnet (Nd:YAG) laser. After four sessions of treatment, the patient displayed nearly complete improvement and no remarkable adverse effects. To the best of the authors' knowledge, this is the first case of the effective treatment of PAE using a 595-nm picosecond-domain Nd:YAG laser. We recommend that using a 595-nm picosecond-domain Nd:YAG laser can be both an effective and safe treatment option for treating PAE.

Use of 1,064-nm Q-switched Neodymium:Yttrium-aluminum-garnet Laser Therapy Assisted with Diamond Particle Suspension and Gold Microparticle Application for Acne Vulgaris and Enlarged Facial Pores

  • Park, Hee Ung;Cho, Hangrae;Lee, Sang Ju;Cho, Han Kyoung
    • Medical Lasers
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    • v.10 no.4
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    • pp.242-245
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    • 2021
  • Acne vulgaris is a common inflammatory skin disease of the pilose-baceous unit. It appears as lesions consisting of comedones, papules, pustules, and nodules of varying shapes and severity. In general, the first-line treatment for acne vulgaris includes topical and oral medication. Recently, various physical modalities have also been investigated. The use of laser therapy is steadily increasing because of its fewer side effects, short procedure time, and rapid results. In particular, laser therapy assisted with carbon suspension application is effective for acne vulgaris but may sometimes result in discomfort due to odor and dust formation during the procedure. Herein, we report that acne vulgaris and enlarged facial pores can be safely and effectively treated with laser therapy assisted with diamond particle suspension and gold microparticle application, which can address the discomfort caused by the carbon suspension application.

Postinflammatory Hyperpigmentation Secondary to Liposuction Successfully Treated with a 1,064-nm Picosecond-Domain Neodymium:Yttrium-Aluminum-Garnet Laser

  • Lee, Hae-Jin;Kim, Young Koo
    • Medical Lasers
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    • v.8 no.2
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    • pp.87-89
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    • 2019
  • Post inflammatory hyperpigmentation (PIH) is a reactive hypermelanosis of the skin that occurs as a result of various inflammatory responses such as surgical procedure, trauma, and many inflammatory conditions. There are several reported studies of various modality in managing PIH. However, the treatment of PIH can prove to be challenging. In this report, we treated a patient with PIH using picosecond-domain Nd:YAG lasers. After ten sessions of 1,064-nm picosecond-domain Nd:YAG laser treatment, the patient presented considerable improvement with no remarkable side effects or recurrence over the duration of 6 months. We suggest that a 1,064-nm picosecond-domain Nd:YAG laser can be effectively and safely used for treating pigmented lesions resulting from surgical procedure in the skin of Asian patients.

Sequential Delivery of Neodymium:Yttrium-Aluminum-Garnet and Alexandrite Laser Pulses for Treating Light Brown Seborrheic Keratoses

  • Cho, Sung Bin;Oh, Doojin;Yoo, Kwang Ho
    • Medical Lasers
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    • v.8 no.1
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    • pp.24-27
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    • 2019
  • Seborrheic keratoses (SKs) have been treated with non-ablative longpulsed (LP) lasers, including LP 532-nm neodymium (Nd): yttrium aluminum garnet (YAG), LP 695-nm ruby, LP 755-nm alexandrite (Alex), and LP 1,064-nm Nd:YAG lasers, with a pulse durations of 1-300 msec. Dual-wavelength LP 755-nm Alex/1,064-nm Nd:YAG laser systems have been used to remove hair follicles and treat various vascular and pigmented disorders by sequentially delivering two pulses of different wavelengths with interpulse intervals in the millisecond range. This paper reports the case of a female patient with multiple, discrete, light brown SKs on the dorsum of both hands that were treated effectively with one session of dual-wavelength LP 1,064-nm Nd:YAG/755-nm Alex laser treatment. The treatment settings for the LP Nd:YAG laser were comprised of a wavelength of 1,064 nm, fluence of 50 J/cm2, pulse duration of 5 msec, and beam size of 3 mm. The settings for the LP Alex laser were comprised of a wavelength of 755 nm, fluence of 50 J/cm2, pulse duration of 5 msec, and beam size of 3 mm. A hybrid mode was used to automatically deliver LP Nd:YAG and LP Alex laser pulses in succession at interpulse intervals of 20 msec. Six weeks after treatment, the patient exhibited remarkable improvement of the light brown seborrheic keratoses and was satisfied with the results.

Microstructural Evolution of Aluminum Nitride - Yttrium Aluminum Garnet Composite Coatings by Plasma Spraying from Different Feedstock Powders (Aluminum Nitride - Yttrium Aluminum Garnet 분말 특성과 플라즈마 용사 코팅층의 미세조직)

  • So, Woong-Sub;Baik, Kyeong-Ho
    • Korean Journal of Materials Research
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    • v.21 no.2
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    • pp.106-110
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    • 2011
  • A high thermal conductive AlN composite coating is attractive in thermal management applications. In this study, AlN-YAG composite coatings were manufactured by atmospheric plasma spraying from two different powders: spray-dried and plasma-treated. The mixture of both AlN and YAG was first mechanically alloyed and then spray-dried to obtain an agglomerated powder. The spray-dried powder was primarily spherical in shape and composed of an agglomerate of primary particles. The decomposition of AlN was pronounced at elevated temperatures due to the porous nature of the spray-dried powder, and was completely eliminated in nitrogen environment. A highly spherical, dense AlN-YAG composite powder was synthesized by plasma alloying and spheroidization (PAS) in an inert gas environment. The AlN-YAG coatings consisted of irregular-shaped, crystalline AlN particles embedded in amorphous YAG phase, indicating solid deposition of AlN and liquid deposition of YAG. The PAS-processed powder produced a lower-porosity and higher-hardness AlN-YAG coating due to a greater degree of melting in the plasma jet, compared to that of the spray-dried powder. The amorphization of the YAG matrix was evidence of melting degree of feedstock powder in flight because a fully molten YAG droplet formed an amorphous phase during splat quenching.

Synthesis and Phase Transformation Behavior of YAG Powders by a Mechanochemical Solid Reaction (기계화학적 고상반응에 의한 YAG 분말의 합성 및 상 형성 거동에 관한 연구)

  • Jung Hyun-Gi;Hwang Gil-Ho;Lim Kwang-Young;Lee Young-Hun;Kang Sung-Goon
    • Journal of Powder Materials
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    • v.13 no.4 s.57
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    • pp.243-249
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    • 2006
  • Yttrium aluminum garnet (YAG) powders were synthesized via mechanochemical solid reaction using $Y_2O_3$ with three types of aluminum compounds. $Y_2O_3$ reacted mechanochemically with all A1 compounds and formed YAM (yttrium aluminum monoclinic), YAG and YAP (yttrium aluminum perovskite) phases depending on the starting materials. The ground samples containing ${\gamma}-A1_2O_3$ showed the best reactivity, whereas the ground sample containing A100H, which had the largest surface area, exhibited pure YAG after calcination at $1200^{\circ}C$. The sample containing Al had the least reactivity, producing YAP along with YAG at $1200^{\circ}C$. The types and grinding characteristics of the starting materials and grinding time are believed to be important factors in the mechanochemical synthesis of YAG.

Luminescence characteristics of YAG:Ce phosphor by combustion method (산화법에 의한 YAG:Ce 형광체의 발광 특성)

  • Choi, Hyung-Wook;Lee, Seung-Kyu;Cha, Jae-Hyeck;Park, Yong-Seo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.322-323
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    • 2006
  • The nano-sized Ce-doped YAG(Yttrium Aluminum Garnet, $Y_3Al_5O_{12}$) phosphor powders were prepared by combustion method from a mixed aqueous solution of metal nitrates, using citric acid as a fuel. The luminescence formation process and structure of phosphor powders were investigated by means of XRD, SEM and PL. The XRD patterns show that YAG phase can form at all of the $Ce^{3+}$ concentration. However, when $Ce^{3+}$ concentration is over 2.0mol%, XRD patterns show $CeO_2$ peak between (321) peak and (400) peak. The pure crystalline YAG:Ce with uniform size of 30nm was obtained at 0.6mol% of the $Ce^{3+}$ concentration. The crystalline YAG:Ce powders showed broad emission peaks in the range 475~630nm and had maximum intensity at 526nm.

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