• 제목/요약/키워드: TEM-52

검색결과 83건 처리시간 0.025초

Microstructure evolution and effect on deuterium retention in oxide dispersion strengthened tungsten during He+ irradiation

  • Ding, Xiao-Yu;Xu, Qiu;Zhu, Xiao-yong;Luo, Lai-Ma;Huang, Jian-Jun;Yu, Bin;Gao, Xiang;Li, Jian-Gang;Wu, Yu-Cheng
    • Nuclear Engineering and Technology
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    • 제52권12호
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    • pp.2860-2866
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    • 2020
  • Oxide dispersion-strengthened materials W-1wt%Pr2O3 and W-1wt%La2O3 were synthesized by wet chemical method and spark plasma sintering. The field emission scanning electron microscopy (FE-SEM) analysis, XRD and Vickers microhardness measurements were conducted to characterize the samples. The irradiations were carried out with a 5 keV helium ion beam to fluences up to 5.0 × 1021 ions/m2 under 600 ℃ using the low-energy ion irradiation system. Transmission electron microscopy (TEM) study was performed to investigate the microstructural evolution in W-1wt%Pr2O3 and W-1wt%La2O3. At 1.0 × 1020 He+/m2, the average loops size of the W-1wt%Pr2O3 was 4.3 nm, much lower than W-1wt% La2O3 of 8.5 nm. However, helium bubbles were not observed throughout in both doped W materials. The effects of pre-irradiation with 1.0 × 1021 He+/m2 on trapping of injected deuterium in doped W was studied by thermal desorption spectrometry (TDS) technique using quadrupole mass spectrometer. Compared with the samples without He+ pre-irradiation, deuterium (D) retention of doped W materials increased after He+ irradiation, whose retention was unsaturated at the damage level of 1.0 × 1022D2+/m2. The present results implied that irradiation effect of He+ ions must be taken into account to evaluate the deuterium retention in fusion material applications.

부산지역(釜山地域) 개업치과(開業齒科)의 치과보철물(齒科補綴物)에 관(關)한 만족도(滿足度) 조사(調査)(I) - 일부정식 치과 보철물에 관하여 - (A Study on Satisfaction of Practicing Dentists about Prosthesis in Pusan Part I : About Fixed Prosthetic appliances)

  • 이명곤
    • 대한치과기공학회지
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    • 제10권1호
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    • pp.159-169
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    • 1988
  • Fixed prosthetic appliance is the restorations of damaged teeth with cast metal or porcelain, and of replacing missing teeth with fixed, or cemented prosthesis. Successfully treating a patient by means of fixed prosthodontics requires the thoughtful combination of dentist and dental laboratory technician. In order to know the satisfaction of dentisits about fixed prosthetic appliances-porcelain, precious and non precious metal-, this study was conducted for 69 practicing dentisis in Pusan during Fed. to Mar. 1988 using a questionnaire method and was analyzed by the use of percentage, $X^2$-test The results are obtained as follow: 1. General characteristics of the respondents, The rate of age distribution of practcing dentists responded was as follow : 31$\sim$35 age group is 29.0%, 51$\sim$55age group 18.8%, 41$\sim$45 age group and 46$\sim$50 group each 11.6%, 36$\sim$40 age group and 56$\sim$60 age group 8.7%, over 60 age group 7.3%, below 30 age group 4.3% respectively. The tate of term of practice experience distribution of dentists responded was as follow : 6$\sim$10 year group 26.1%, 25$\sim$25year group 18.8%, 11$\sim$15 years group and 16~20 years group each 13.0%, below 5 years group and over 30 years group each 10.2%, 26$\sim$30 years group 8.7% in order. The rate of respondents’ degree was follow : bachelor group 81.2%, doctor group 13.0%, master group 5.8% in order. The rate of respondents’completed medical specialist course was as follow : non-complete group 75.4%, complete group 24.6%. The rate of having own laboratory in respondents’clinic was as follow : no having own laboratory group 58.0%, having own labiratory group 42.0% The rate of being lab. technician in respondent;s clinic was as follow: non-being lab. technician group 91.3%, being lab. technician group 8.7%. The rate of transactional commercial dental lab. numbers was as follow : I dental lab. group 40.6%, 2 dental lab. group 30.4%, 3 dental lab. group 20.3%, production at own lab. group 8.7% 2. Cognitions about the respondent's job, About cognition of patient numvers, there were neither many nor few group 62.3%, few group 17.4%, many group 15.9%, too many group 4.4% in order.(P<.01) As compared with the ratio of dentists to patient prothetic treatment, there were moderate level group 46.4%, high level group 33.6%, low level group 18.8% in order.(P<.01) By job satisfaction of respondents, the highest percentage group was satisfied group 44.9%, neither astisfied nor disstified group 33.3%, dissatisfied group 14.5%, much satisfied group 7.3%(P<.01). As compared with the level of prosthetics price, the were moderate level group 71.0%, low level group 23.2%, high level group 5.8%(P<.01) 3. Satisfaction and assessment of dissatisfied factor of the fixed prosthetic appliance, As compared with the satisfaction of al prosthetic appliance, there were neither satisfied nor dissatisfied group 59.4%, satisfied group 20.3% dissatisfied group 18.8%, much satisfied group 1.5% in order.(P<.01). About precious and non precious metal crown and bridge, there were neither satisfied nor dissatisfied group 60.9%, satisfied group 24.6%, dissatisfied group 11.6%, much satisfied group 2.9% in order.(P<.01) The reat of respondent;s satisfaction about porcelain crown and bridge was as follow : neither satisfied nor dissatisfied group 43.5%, dissatisfied group 33.3%, satisfied group 21.7%, much satisfied group 1.5%(P<.01). The rate of respondent's dissatisfied factor item of precious and non precious metal crown and bridge was as follow : inadequate margin fit item 39.1% respondent, inadequate occlusion item 24.6%, inadequate adaptation item 23.2%, poor anat omic form item 15.9%, inadequate contact item 31.9%, improper polishing item 4.4%, the rest item 11.6% respectively. The rate of respondent's dissatisfied factor item of porcelain crown and bridge was as follow : inadequate margin fit item 52.2%, inadequate occlusion item 2.9%, inadequate adaptation item 10.1%, poor anatomic form item 11.6%, improper polishing item 1.5%, shade mismatching item 71%, the rest item 7.2% respectively. The rate of cognition of respondents’ about cause of dissatisfied factor on fixed prosthetic appliance by item was as follow : deficiency of sincerity item 55.1%, deficiency of knowledge about work item 47.8%, deficiency of experience item 15.9%, poor quality of using material item 5.8%, the rest item 2.9% respectively.

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서울시내 건축물 석면해체·제거 사업장 및 주변에서의 공기 중 석면농도 특성에 관한 연구 (A Study on Characteristics of Airborne Asbestos Concentrations at Demolition Sites and Surrounding Areas of Asbestos Containing Buildings in Seoul)

  • 이진효;이수현;김정연;김지희;정숙녀;김진아;김익수;어수미;정권;이진숙;구자용
    • 대한환경공학회지
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    • 제36권6호
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    • pp.434-441
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    • 2014
  • 본 연구에서는 석면해체 제거작업에 따른 작업자 및 주변 환경에 미치는 영향 등을 파악하기 위해 서울시내 건축물 석면해체 제거 사업장을 대상으로 공기 중 석면농도를 조사하고, 측정결과가 "석면안전관리법"에서 명시된 사업장 주변의 석면배출허용기준에 적합한지를 살펴보았다. 서울시내 총 37개소 석면해체 제거 사업장에서 총 288개의 공기 중 시료를 분석하였으며, 전체 288개 시료 중 101개 시료에서(35%) 검출한계($7fiber/mm^2$) 이하로 나타났다. 이 때 전체 공기 중 석면농도 평균값은 $0.003{\pm}0.002f/cc$로(최대 0.013 f/cc) 대부분의 공기 중 석면농도는 "석면안전관리법"에서 명시된 사업장 주변의 석면배출허용기준 0.01 f/cc 이하로 나타나 서울시내 건축물 석면해체 제거 사업장에서의 석면 노출가능성은 우려할 수준이 아닌 것으로 판단된다. 채취지점별로 살펴보면, 부지경계선(148개), 위생설비입구(25개), 작업장주변(실내)(7개), 작업장주변(실외)(11개)에 대한 공기 중 석면농도 결과, 각각 53개(36%), 5개(20%), 1개(14%), 4개(36%) 시료에서 검출한계 이하로 나타났으며 평균농도는 각각 $0.002{\pm}0.002f/cc$(최대 0.008 f/cc), $0.004{\pm}0.002f/cc$(최대 0.009 f/cc), $0.004{\pm}0.002f/cc$(최대 0.007 f/cc), $0.004{\pm}0.002f/cc$로(최대 0.008 f/cc) 나타났다. 또한 음압기(13개), 폐기물보관지점(27개), 폐기물반출구(9개), 거주자주거지역(48개)에 대한 공기 중 석면농도 결과, 각각 3개(23%), 8개(30%), 2개(22%), 25개(52%) 시료에서 검출한계 이하로 나타났으며 평균농도는 각각 $0.004{\pm}0.002f/cc$(최대 0.009 f/cc), $0.005{\pm}0.004f/cc$(최대 0.013 f/cc), $0.005{\pm}0.003f/cc$(최대 0.009 f/cc), $0.003{\pm}0.002f/cc$0로(최대 0.009 f/cc) 나타났다.