• Title/Summary/Keyword: Thermal post-treatment

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Zirconia galvani sensor for the measurement of oxygen activity (용존산소활량 측정용 지르코니아 갈바니 센서)

  • Oh, Young-Jei
    • Journal of Sensor Science and Technology
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    • v.18 no.6
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    • pp.441-448
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    • 2009
  • Magnesia partially stabilized zirconia(Mg-PSZ) solid electrolytes for an improvement of thermal shock resistance, which is suitable for the measurement of oxygen activity in a molten steel, were prepared by post-thermal aging treatment. The steelmaking oxygen sensor elements were formed by an injection molding method, sintered at $1650^{\circ}C$, and then thermal aged ranged from 1250 to $1400^{\circ}C$. Sintered density and porosity were decreased as increasing the magnesia content in a zirconia-magnesia solid solution. Fractions of cubic phase to the synthesized Mg-PSZ solid electrolytes were ranged from 13.13 to 79.54.% after post-thermal aging treatment. Very dense microstructure without voids in the grains was obtained by the post-thermal aging process. Fine tetragonal phase crystallites precipitated on the cubic surface during post-thermal aging up to $1300^{\circ}C$ improve a thermal shock resistance and reappearance of electro motive force(EMF) curve.

Effect of Post-Heat-Treatment on Various Characteristics of Commercial Pitch-Based Carbon Fibers

  • Yoon, Sung-Bong;Cho, Chae-Wook;Cho, Dong-Hwan;Park, Jong-Kyoo;Lee, Jae-Yeol
    • Carbon letters
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    • v.8 no.2
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    • pp.127-133
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    • 2007
  • In this study, commercially available pitch-based carbon fibers of general grade were post-heat-treated using a boxtype high temperature furnace at $1800^{\circ}C$, $2000^{\circ}$, $2200^{\circ}C$, and $2400^{\circ}C$, respectively. The fundamental characteristics of each heat-treated carbon fibers were investigated in terms of chemical composition, morphology, thermal stability, X-ray diffraction, single filament tensile test, and electrical resistivity. The result showed that the fiber properties were significantly influenced by the post-heat-treatment, indicating the greater effect with increasing treatment temperature. The carbon contents, thermal stability, and tensile properties of the carbon fibers used here were further increased by the post-heat-treatment, whereas the d-spacing between graphene layers and the electrical resistivity were reduced with increasing post-heat-treatment temperature.

A clinical report of thermographic change after Korean Medicine Treatment on post-hysterectomy syndrome patients (자궁적출술 후 증후군의 한방치료 전후 체온분포 변화에 관한 임상보고)

  • Kim, Jihee;Lee, Gi-Seung;Kim, Jun-Cheol
    • Journal of Korean Medical Ki-Gong Academy
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    • v.14 no.1
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    • pp.52-62
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    • 2014
  • Objective : The aim of this study is to analyze the effectiveness of Korean Medicine treatment on post-hysterectomy syndrome patients by thermographic change during treatment. Methods : 5 female patients who had a hysterectomy within a year were treated with Korean Medicine concluding acupuncture, herbal medicine, cupping therapy, herbal bath. We evaluated the thermographic differences by checking Digital Infrared Thermal Imaging(D.I.T.I.) at CV17(膻中), CV4(關元), ST3(巨髎), BL15(心兪), and BL23(腎兪). Results : In consequence of Korean Medicine Treatment for 3 weeks, thermographic differences between CV17(膻中) and CV4(關元), ST3(巨髎) and CV4(關元), BL15(心兪), and BL23(腎兪) tended to decrease. Conclusion : After Korean Medicine treatment, thermographic differences between upper body and lower body tended to decrease cause shangrexiahanzheng(上熱下寒證) made by hysterectomy became moderated.

Numerical analysis of post welding heat treatment base on the thermal creep elastic-plastic theory (점열탄소성 이론에 의한 용접후열처리에 대한 수치해석)

  • 방한서;차용훈;오율권;노찬승;김종명
    • Journal of Ocean Engineering and Technology
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    • v.11 no.1
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    • pp.113-123
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    • 1997
  • The welding residual stresses produced by welding frequently cause a crack and promote stress corrosion etc. in heat affected zone contained with external load and weakness of material. For the purpose pof relaxation of welding residual stress, post welding heat teratment(PWHT) is widely used. In this paper, the computer program which is based on Thermal-Elasto-plastic-creep theory for plane deformation on developed by finite element method (F.E.M) and verified its propriety by experimental measurement and also by using the developed computer program. The mechanical behavior of butt welding joint is clairfied during PWHT.

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The Effects of Lumbar Stabilizing Exercise on the Functional Recovery and the Range of Motion of Low Back Pain Patients (요부 안정화 운동이 요통환자의 기능회복과 가동범위에 미치는 영향)

  • Jung Yeon-Woo;Bae Sung-Soo
    • The Journal of Korean Physical Therapy
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    • v.16 no.1
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    • pp.157-182
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    • 2004
  • The purpose of this study was to evaluate effects of lumbar stabilizing exercise on the functional recovery and the range of motion of low back pain patients. The subjects were consisted of sixty patients who had non specific chronic low back pain(32 females. 28 males; mean aged 37.3) from 19 to 65 years of age(mean age : 37.3). All subjects randomly assigned to the lumbar stabilizing exercise group, the modalities treatment group, the manual treatment group. Lumbar stabilizing exercise group received manual treatment with lumbar stabilizing exercise for 30minutes, modalities treatment group received hot pack used thermal therapy for 20minutes and ICT used electrical therapy for 20minutes and US or MWD used deep thermal therapy for 15minutes, manual treatment group received modalities treatment with therapeutic massage for 10minutes and joint mobilization or manipulation for 10minutes per day and three times a week during 4 weeks period. The Multilevel Roland-Morris Disability Questionnaire(MR-MDQ) was used to measure functional disability level. Visual Analogue Scale(VAS) was used to measure subjective pain level. Remodified Schober test(RST) was used to measure forward flexion range of motion of lumbar segment. Finger-to-Floor test(F-T-FT) was used to measure forward flexion range of motion of full spine of low back pain patients. All measurements of each patients were measured at pre-treatment and 4 week post-treatment. The results of this study were summarized as follows : 1. The MR-MDQ of lumbar stabilizing exercise group, modalities treatment group, and manual treatment group was significantly reduced between pre-treatment and post-treatment(p<.05). 2. The VAS of lumbar stabilizing exercise group, modalities treatment group, and manual treatment group was significantly reduced between pre-treatment and post-treatment(p<.05). 3. The RST of lumbar stabilizing exercise group, modalities treatment group, and manual treatment group was significantly reduced between pre-treatment and post-treatment(p<.05). 4. The F-T-FT of lumbar stabilizing exercise group, modalities treatment group, and manual treatment group was significantly reduced between pre-treatment and post-treatment(p<.05). 5. The results of analyzed effects of MR-MDQ, RST, F-T-FT were significantly reduced (p<.05), but VAS wasn't significantly reduced(p>.05) between treatment type of lumbar stabilizing exercise group and modalities treatment group and manual treatment group according to pre-treatment and post-treatment. 6. The results of LSD post-hoc to find difference between treatment type of lumbar stabilizing exercise group and modalities treatment group and manual treatment group according to pre-treatment and post-treatment that MR-MDQ was significantly reduced stabilizing exercise group than modalities treatment group(p<.05), and VAS wasn't significantly reduced all treatment group(p>.05), and RST was significantly reduced stabilizing exercise group than modalities treatment group(p<.05), and F-T-FT was significantly reduced stabilizing exercise group than modalities treatment group and manual treatment group (p<.05).

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A Study on the Mechanical Behavior of Welded Parts in Thick Plate during Post Welding Heat Treatment (厚板熔接部의 應力除去 熱處理時의 力學的 擧動에 關한 硏究)

  • 방한서
    • Journal of Welding and Joining
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    • v.11 no.4
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    • pp.103-111
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    • 1993
  • Recently, several high-tensile steels(e.g. 80kg and above, $2^{1/4}Cr$-1Mo)having good quality to high temperature and pressure-resistance are widely used to construct petroleum-plant and pressure vessel of heat or nuclear-power plant. However, in the steels, reheating crack at grain boundaries of the heat affected zone(HAZ) occures during post welding heat treatment(PWHT)to remove welding residual stress. In order to study theoretically the characteristics of reheating crack created by PWHT, the computer program of three-dimensional thermal-elasto-plasto-creep analysis based on finite element method are developed, and then the mechanical behavior(history of creep strain accumulation and stress relaxation, etc)of welded join in thick plate during PWTH is clarified by the numerical results.

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A Study on the Creep Characteristics according to Groove Shape of T-Welded Joint (T-Joint 용접부의 Groove형상별 크리프 특성에 관한 연구)

  • Bang, Han-Seo;Kim, Jong-Myeong
    • Journal of Ocean Engineering and Technology
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    • v.13 no.3 s.33
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    • pp.68-76
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    • 1999
  • The welding residual stresses produced by the welding frequently caused a crack and promote stress corrosion etc. in HAZ(heat affected zone) contained with external load and weakness of material. Therefore, PWHT(post welding heat treatment) is widely used to reduce wekdubg residuss, to relax hardening of heat affected zone and to get rid of impurity. In this study, in order to define the effect on shappes of T-welded joint, during the post welding heat treatment, we have carried out numerical analyses on the several test pieces by using computer program which was based on thermal-elasto-plato-plasto-creep theories for the study. The main results obtained form this study is as follows: 1) The mechanical difference for change the thickness of plate and groove angle did not appear. 2) The distribution modes of welding residual stresses are same on the all test specimens during the post welding heat treatment. 3) In a mecharical point of view, minimum groove groove angle($40^{circ}$) is more suitable than maximum groove angle($60^{circ}$). 4) Therefore, it is appropriate to minimize the size of groove shape in strength and safety.

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Study of Carbon Nanotubes Properties by Post-treatment Conditions (후처리 조건에 따른 탄소나노튜브 특성의 변화)

  • Choi Sung-Hun;Lee Jae-Hyeong;Yang Jong-Seok;Park Dae-Hee;Heo Jeong-Ku
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.10
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    • pp.930-934
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    • 2006
  • This paper reports a change of carbon nanotubes(CNTs) properties by post-treatment process after growth of CNTs. CNTs were treated by thermal method and solution method, and then investigated in detail using field emission scanning electron microscopy(FE-SEM), high resolution transmission scanning electron microscopy(HR-TEM), RAMAN spectroscopy, and Fourier Transform Infrared Spectrometer (FT-IR). FT-IR spectra showed that the amount of hydroxyl generated on surface of CNTs were changed with post-treatment condition. FE-SEM and TEM images were shown CNTs diameter and density variations were dependent with their treatment conditions. RAMAN spectroscopy was shown that carbon nanotubes structure vary with treatment conditions.

Influence of CrO3 Sealing Treatment on Properties of Plasma Sprayed Al2O3 Coating (플라즈마 용사 Al2O3 코팅의 특성에 미치는 CrO3 봉공처리의 영향)

  • Cho, Kyeong-Sik;Lee, Hyun-Kwuon;Kwon, Jeong-Cheol
    • Journal of the Korean Ceramic Society
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    • v.48 no.2
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    • pp.160-167
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    • 2011
  • Plasma sprayed ceramic coatings inherently contain pores and usually also cracks. Post-treatment of the plasma sprayed coatings is a way to close the connected pores and cracks. In this study, post-sealing treatment in plasma sprayed $Al_2O_3$ coatings was employed to overcome the reduction of coating properties. $Al_2O_3$ plasma thermal spray coating was made on aluminum alloys plate, $CrO_3$ post coating and heat treatment at $550^{\circ}C$ was carried out in order for final $Cr_2O_3$ to be saturated through phase transformation. Chromia sealing began at the fine defect in coated microstructure, while larger pores were permeated later. The increase in concentration and treatment frequency of sealing solution resulted in the decrease of porosity of coating layer, while cracks occurred partially after the third treatment. After twice treatment of 10M $CrO_3$ solution, microhardness and breakdown voltage of $Al_2O_3$ coatings were found to increase by ${\fallingdotseq}$ 50% and ${\fallingdotseq}$ 390% respectively than without post-treatment.

Thermal Stability of TiN/Ti Barrier Metals with Al Overlayers and Si Substrates Modified under Different Annealing Histories (형성조건에 따른 TiN/Ti Barrier Metal의 Al 및 Si 과의 열적 안정성)

  • 신두식;오재응;유성룡;최진석;백수현;이상인;이정규;이종길
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.30A no.7
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    • pp.47-59
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    • 1993
  • The thermal stability of "stuffed" TiN/Ti barrier matals with different annealing history has been studied to improve the contact reliability of Al/Si contacts in 16M DRAM. The annealing conditions before the Al deposition such as film thickness, the annealing temperature and the annealing ambient have been varied. For TiN(900A)/Ti(300A) annealed at 450 in nitrogen ambient to form a "stuffed barrier" by inducing oxygen atoms into grain boundaries, there is no observation of Al penetrations into Si substrates after the post heat treatment of up to 700 even though there are massive amounts of Al found in TiN film after the post heat treatment of 600 indicating that TiN has a "sponge-like" function due to its ability to absorb several amounts of aluminum at elevated temperature. The TiN/Ti diffusion barrier annealed at 550 has, however, failed after the post heat treatment at 600. The thinner diffusion barriers with TiN(300A)/Ti(100A) failed after the post heat treatment at 600.he post heat treatment at 600.

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