• 제목/요약/키워드: $Bi_{2}O_{3}$

검색결과 1,154건 처리시간 0.035초

유기금속염을 이용한 고효율 전력 전송용 초전도 전구체 합성 (Synthesis of high functional Superconducting Precursor using Organic metal salts method for Electric power transmission)

  • 이상헌
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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    • pp.270-271
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    • 2005
  • A high Tc superconducting with a nominal composition of $Bi_2Sr_2Ca_2Cu_3O_Y$ was prepared by the citarte method. The solid precursor produced by the dehydration of the gel at $120^{\circ}C$ for 12h is not in the amorphous state as expected but in a crystalline state. X-ray diffraction peaks of nearly the same angular position as the peaks of high Tc phase were observed in the precursor. After pyrolysis at $400^{\circ}C$ and calcination at $840^{\circ}C$ for 4h, the (001)peak of the high Tc phase was cleary observed. Experimental results suggest that the intermediate phase formed before the formation of the superconducting phase may be the most important factro in determining whether it is easy to form the high Tc phase or not. because the nucleation barriers of the two superconducting phase may be altered by the variation of the crystal structures of those intermediate phase.

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Comparison of Characteristics of Gamma-Ray Imager Based on Coded Aperture by Varying the Thickness of the BGO Scintillator

  • Seoryeong Park;Mark D. Hammig;Manhee Jeong
    • Journal of Radiation Protection and Research
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    • 제47권4호
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    • pp.214-225
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    • 2022
  • Background: The conventional cerium-doped Gd2Al2Ga3O12 (GAGG(Ce)) scintillator-based gamma-ray imager has a bulky detector, which can lead to incorrect positioning of the gammaray source if the shielding against background radiation is not appropriately designed. In addition, portability is important in complex environments such as inside nuclear power plants, yet existing gamma-ray imager based on a tungsten mask tends to be weighty and therefore difficult to handle. Motivated by the need to develop a system that is not sensitive to background radiation and is portable, we changed the material of the scintillator and the coded aperture. Materials and Methods: The existing GAGG(Ce) was replaced with Bi4Ge3O12 (BGO), a scintillator with high gamma-ray detection efficiency but low energy resolution, and replaced the tungsten (W) used in the existing coded aperture with lead (Pb). Each BGO scintillator is pixelated with 144 elements (12 × 12), and each pixel has an area of 4 mm × 4 mm and the scintillator thickness ranges from 5 to 20 mm (5, 10, and 20 mm). A coded aperture consisting of Pb with a thickness of 20 mm was applied to the BGO scintillators of all thicknesses. Results and Discussion: Spectroscopic characterization, imaging performance, and image quality evaluation revealed the 10 mm-thick BGO scintillators enabled the portable gamma-ray imager to deliver optimal performance. Although its performance is slightly inferior to that of existing GAGG(Ce)-based gamma-ray imager, the results confirmed that the manufacturing cost and the system's overall weight can be reduced. Conclusion: Despite the spectral characteristics, imaging system performance, and image quality is slightly lower than that of GAGG(Ce), the results show that BGO scintillators are preferable for gamma-ray imaging systems in terms of cost and ease of deployment, and the proposed design is well worth applying to systems intended for use in areas that do not require high precision.

60세 이상의 고령에서의 중족골 절골술을 이용한 무지 외반증 치료 (Treatment for Hallux Valgus with Chevron Metatarsal Osteotomy in Patients over 60 Years Old)

  • 정비오;이상현
    • 대한족부족관절학회지
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    • 제16권4호
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    • pp.223-228
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    • 2012
  • Purpose: To treat hallux valgus in old age patients with chevron metatarsal osteotomy and to see the subsequent clinical and radiological outcomes. Materials and Methods: 23 cases of 18 hallux valgus patients of age 60 years or older who received proximal or distal corrective osteotomy from April 2007 to August 2009 and were followed up for at least 1 year were included in the study. The mean age at operation was 65 years (range, 60~81 years), and the mean follow-up period was 2 years and 6 months (range, 1 year~3 years 6 months). Clinical outcome was assessed with the American Orthopaedic Foot and Ankle Society (AOFAS) score, complications, satisfaction rate, as well as measurements and comparison of pre- and postoperative hallux valgus angles, the 1st~2nd intermetatarsal angle, and the position of hallucal medial sesamoid bone. Results: The AOFAS score was improved from preoperative average of 35.1 (range, 13-47) to average 85.1 at last follow-up (range, 75-100). Patients were satisfied about the operation in 21 cases (91.3%). Preoperative hallux valgus angle was $31.7^{\circ}$ on average (range, $19.1^{\circ}-48.9^{\circ}$), and $4.9^{\circ}$ on average at last follow-up (range, $0.3^{\circ}-21.2^{\circ}$). The 1st~2nd intermetatarsal angle was $14.4^{\circ}$on average (range, $8.7^{\circ}-25.7^{\circ}$) and $3.1^{\circ}$ on average at last follow-up (range, $0.6^{\circ}-7.5^{\circ}$). The hallucal medial sesamoid bone position was improved from preoperative average 3.5 (range, 3-4) to postoperative average 1.0 (range, 0-2). Conclusion: Proximal and distal metatarsal osteotomy treatment yielded good clinical and radiological outcomes in old age hallux valgus patients.

유방 양성 종괴 추적 관찰 환자에게서 발견된 관상피내암 증례 보고 (A Case Report of Intraductal Carcinoma Detected in a Patient Undergoing Surveillance for Benign Breast Mass)

  • 문일봉;곽종길;전철민
    • 한국방사선학회논문지
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    • 제17권5호
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    • pp.743-749
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    • 2023
  • 유방의 관상피내암(DCIS; ductal carcinoma in situ)은 유방의 상피세포가 악성화되었지만, 아직 정상적인 유관에 한정되어 있는 경우를 지칭하며, 최근 빠르게 증가하고 있다. 본 증례에서 추적관찰 2년 동안은 유방 촬영술 및 초음파 검사상 병변은 BI-RADS Category 3으로 분류되는 작은 mass가 관찰되었지만 낭성 mass 소견을 보여, 전형적인 악성 종양의 소견과는 거리가 있었으나 추적관찰 2년째에 유방초음파상 우측 유방 6시 방향에 불분명한 경계(Lobulated margin)를 보이는 저에코(hypoechoic) 종괴가 약 2.1 × 1.3 cm 크기로 보였으며 조직 검사상 관상피내암으로 진단되었다. 관상피내암은 특징적인 임상소견이 없고 초기에 양성의 임상, 영상 소견을 보일 수 있으므로 정기적인 추적관찰을 시행하는 것이 조기 진단에 중요할 것으로 사료되며, 유방촬영술과 초음파 검사로 관상피내암을 발견하는 것은 유방암 환자 전체의 예후를 좋게 하는 데에 중요하다고 할 수 있겠다. 4년 전 처음 검사 시 증상이 없으며 유방촬영상 정상이고 유방초음파상 악성 징후 없는 낭성병변이 추적관찰 중에 관상피내암의 소견인 비대칭 음영과 미세석회화, 분엽상의 mass가 관찰된 관상피내암의 증례를 보고한다.

Identification of a Proper Phytoavailable Arsenic Extraction Method Associated with Arsenic Concentration in Edible Part of three Crops in Soils Near Abandoned Mining Areas

  • Yoon, Jung-Hwan;Kim, Young-Nam;Lee, Dan-Bi;Kim, Kwon-Rae;Kim, Won-Il;Kim, Kye-Hoon
    • 한국토양비료학회지
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    • 제50권6호
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    • pp.497-508
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    • 2017
  • This study aimed to investigate correlations between concentrations of extractable Arsenic (As) with varying chemical solutions (0.1 M $Ca(NO_3)_2$, 0.1 M $(NH_4)2HPO_4$, 0.5 M EDTA, Mehlich 3, and 0.5 M $NaHCO_3$) and those of As in crops, and then to seek the most suitable soil extraction method for predicting the potential of As uptake in crops cultivated in soils contaminated with As. For a mesocosm experiment, pepper (Capsicum annuum L.), soybean (Glycine max L.), and rice (Oryza sativa L.) were cultivated for three months in pots containing soils taken from the arable areas near abandoned mines in Korea. Following the cultivation, soil pH and DOC significantly increased by treatments of lime and lime plus compost, respectively, while insignificant influences in changing total and all extractable As concentrations were found in all soils. Arsenic concentration in edible part of all crops considerably depended on the extractable As concentration in the soils, particularly with Mehlich 3. All extractable As concentrations in the soils of C. annuum and G. max were significantly correlated with As concentration in their edible parts. For O. sativa, the extractable concentrations of Mehlich 3 ($R^2$: 0.18 at p: 0.006) and EDTA ($R^2$: 0.11 at p: 0.036) showed only marked relationships with As concentration in the edible part. These results may indicate that the Mehlich 3 and EDTA are soil extractants to determine phytoavailable As in soil that provide better prediction for As transfer from soil to crop.

Surface Protection Obtained by Anodic Oxidation of New Ti-Ta-Zr Alloy

  • Vasilescu, C.;Drob, S.I.;Calderon Moreno, J.M.;Drob, P.;Popa, M.;Vasilescu, E.
    • Corrosion Science and Technology
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    • 제17권2호
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    • pp.45-53
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    • 2018
  • A new 80Ti-15Ta-5Zr wt% alloy surface was protected by anodic oxidation in phosphoric acid solution. The protective oxide layer (TiO2, ZrO2 and Ta suboxides and thickness of 15.5 nm) incorporated $PO{_4}^{3-}$ ions from the solution, according to high resolution XPS spectra. The AFM analysis determined a high roughness with SEM detected pores (20 - 50 nm). The electrochemical studies of bare and anodically oxidized Ti-15Ta-5Zr alloy in Carter-Brugirard saliva of different pH values and saliva with 0.05M NaF, pointed to a nobler surface for the protected alloy, with a thicker electrodeposited oxide layer acting as a barrier against aggressive ions. The oxidized alloy significantly decreased corrosion current densities and total quantity of ions released into the oral environment in comparison with the bare one, at higher polarisation resistance and protective capacity of the electrodeposited layer. The impedance data revealed a bi-layered oxidation film formed by: a dense, compact, barrier layer in contact with the metallic substrate, decreasing the potential gradient across the metal/oxide layer/solution interface, reducing the anodic dissolution and a more permissive, porous layer in contact with the electrolyte. The open circuit potential for protected alloy shifted to nobler values, with thickening of the oxidation film signifying long-term protection.

바이컨티니어스 큐빅상 액정의 생성과 자기조직화 (Self Assembly and Formation of Bi-continuous Cubic Liquid Crystalline Phase)

  • 김인영;최화숙;이소라;최성호
    • 한국응용과학기술학회지
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    • 제31권3호
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    • pp.478-485
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    • 2014
  • 이 연구는 경표피흡수를 위하여 큐빅액정의 자기조직체의 형성에 관한 것이다. 복수 수산기(-OH)를 가지는 친수부에 4개의 메칠 그룹을 가지는 양친매성지질인 diglyceryl phytylacetate (DGPA)를 합성하여 다양한 성능평가를 수행하였다. DGPA의 유화력은 1%의 적은 농도에서도 고 내상의 물을 함유하는 안정한 W/O water-in-oil)에멀젼이 유지되었다. DGPA, dimethicone (2CS), water의 3성분계의 특정영역에서, 안정한 큐빅상의 액정이 형성되었다. 3상 구조도 작성을 통하여 큐빅 액정영역, 헥사고날 영역, 물과 헥사고날이 혼제된 영역, 역미셀 영역을 확인하였고, SAXS (small angled x-ray scattering)분석을 통하여 그 구조를 증명하였다. 화장품의 응용으로, 큐보좀 (cubosome)에 10%의 마그네슘아스코르빌포스페이트, 5%의 피리독신트리헥사데카노에이트를 봉입하여 캡슐화하였다. 큐보좀의 occlusive 효과는 역미셀(reverse micelle)보다 1.7배 우수한 효과를 가졌다. 큐보좀을 분산제인 poloxamer를 사용하여 W/O 에멀젼을 만든 것으로부터 큐빅구조의 액정상으로 회복되는 것을 새롭게 발견하였다. 따라서, DGPA의 양친매성지질의 특성을 이용하여, 큐빅상의 액정을 형성하는 기재로써 화장품 산업과 의약품분야에서 경표피흡수제로써 응용이 가능할 것으로 기대된다.

폐적(肺積) 폐옹(肺癰) 폐저(肺疽) 폐암(肺癌)에 관(關)한 문헌적(文獻的) 고찰(考察) (The bibliographical study on Pyu-Juk (肺積), Pyu-Ong(肺癰), Pyu-Ju(肺疽), Pyu-Am(肺癌))

  • 한재수;오태환;정승기;이형구
    • 대한한방내과학회지
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    • 제12권2호
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    • pp.113-128
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    • 1991
  • This study has been carried out to investigate Pyu-Juk ( 肺積 ), Pyu-Ong ( 肺癰 ), Pyu-Ju ( 肺疽 ), Pyu-Am ( 肺癌 ) by referring to 56 literatures. The results were obtained as follows; 1. The treatllent-method of Pyu-Juk ( 肺積 ) are Ik Ki ( 益氣 ), SuI Yem Wha ( 洩陰火 ), So Juk ( 消積 ), Wha Juk ( 化積 ), Son Juk ( 損積 ), Ma Juk ( 摩積 ) Jo Chil Gi ( 調七氣 ), and herbs are Sik Bun Tang ( 息賁湯 ), Sik Bun Hwan ( 息賁丸 ), O Juk Hwan ( 五積丸 ), Ban ha Tang ( 半夏湯 ), Gil Gyung Tang ( 桔梗湯 ), Dae Chil Gi Tang ( 大七氣湯 ), Chil Gi Hwan ( 七氣湯 ) , Ga Gam Sik BlDl Hwan ( 加減息賁丸 ), Bil Rang San ( 檳郞散 ). 2. The treatment-method of Pyu-Ong ( 肺癰 ) Yang pyu ( 養肺 ), Yang Hyul ( 養血 ), Yang Gi ( 陽氣 ), Chung Geam Youn Pye ( 淸金潤肺 ), Hal Dam Bae Nong ( 豁痰排膿 ), Saeng Gi ( 生肌 ), herbs are Gil Gyung Tang ( 桔梗湯 ), Jung Ryuk Dae Jo Sa Pyu Tang ( ??大棗瀉肺湯 ), Chung Geom Wy Gyung Tang ( 千金 葦莖湯 ) Hwang Gi tang ( 黃嗜湯 ), Hyun Sam Chung Pyu Eum ( 玄蔘淸肺飮 ), Sip Mi Hwan ( 十味丸 ), Gil Gyung Baek San ( 桔梗白散 ), So Hong Eum ( 消膿飮 ), Sam Gi Bo Pyu Tang ( 蔘嗜補肺湯 ), sam Chul Gun Bi Tang ( 蔘朮健脾湯 ), Chung Pyu Gil Gyung Tang ( 淸肺桔梗湯 ), Yu Sung Hwan ( 如聖丸 ). 3. The treatment-method of Pyu-Ju ( 肺疽 ) are Be Bi ( 補脾 ), Bo Pyu ( 補肺 ), herbs are Hwang Gi Gum Jung Tang( 黃嗜補裨湯 ), lnSamBoPyuSan (人蔘補肺散) 4. The treatment-method of Pyu-Am ( 肺癌 ) are Bal Han ( 發汗 ), Chung Yul Hae Dok ( 淸熱解毒 ), Gang Hwa Do Dam ( 降火導痰 ), Hwa Rak Hwa a ( 和絡化瘀 ) Ik Pyu ( 益肺 ), Gun Bi ( 健脾 ), Ja Eum Yun Pyu ( 滋陰潤肺 ), Gi Hu Yang Bo ( 氣虛兩補 ), herbs are Gyul Yua Hae Dok Tang ( 莖熱解毒湯 ), Gang Hwa Jae ( 降火劑 ), Chil Yul Do Dam Tang ( 治熱導痰湯 ), Chong Ho Byul Gap Tang ( 靑蒿鱉甲湯 ), Ga gam Gil Gyung Tang ( 加減桔梗湯 ), Sang Mak San ( 生脈散), Yuk Mi Ji Hwang Tang ( 六味地黃湯 ), Baek Hap Go Geum Tang ( 百合固金湯 ), Dae Be Won Jun ( 大補元煎 ), Ga Mi Jae Che Bo Pyu Tang ( 加味載體補肺湯 ).

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EDS (Energy Dispersive Spectrometry)를 이용한 Mineral Trioxide Aggregate와 3종의 포틀랜드 시멘트의 성분비교에 관한 연구 (Analysis of Chemical Constitutions of MTA and 3 Portland Cements)

  • 장석우;배광식
    • 구강회복응용과학지
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    • 제23권1호
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    • pp.79-84
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    • 2007
  • Mineral Trioxide Aggregate(MTA) has been used in Endodontic treatment successfully for more than 10 years. But the high cost of MTA limits its use in endodontics in Korea. Recently many studies have been done to compare MTA and Portland cements. To investigate the chemical constitutions of MTA (Proroot MTA, Tulsa Dental), Gray Portland cement (Lafarge Halla cement), White Portland cement(Union corp), and fast setting cement (SSangyong cement), we performed SEM(scanning electron microscope)(S4700, Hitachi) examination and EDS(Energy dispersive spectrometry)(emax, Horiba) analysis. SEM examination and EDS analysis were committed to and performed in SNU DRI (Seoul National University Dental Research Institute). We found that particles of MTA were relatively round, uniform in size, and compactly packed compared to Portland cements. Chemical constitutions of MTA, GPC, WPC and FSC were similar. It was shown that MTA contains much BiO2 . MTA and WPC showed less heavy metals such as Fe and Mg compared to GPC and FSC. FSC showed remarkably high aluminum content.

7종 야생초의 식용화를 위한 조리방법에 관한 연구-관능검사를 중심으로- (A Study of Cooking Method of 7 Kinds of Wild Grasses for the Utility as an Edible Vegetables)

  • 이혜정;이경희;구성자
    • 한국식품조리과학회지
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    • 제10권3호
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    • pp.260-266
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    • 1994
  • The object of this study was investigation of the appreciable cooking condition in seven wild grasses, an evening primerose(Oenothera lamarckiana Seringe, S$_1$), a spiderwort(Commelina Communis L. S$_2$), the flower of a convolvulus(Calystegia Ja-ponica form Vulgaris gaea, S$_3$), So Ru Jaeng Yi(Portulaca Oleracea, S$_4$), Shoe Bi Rum(Portulacae Oleracea L, S$_5$), O Yi Pul(Sanguisorb aOfficinalis, S$_6$), Jip Sin Na Mul(Agrimonia poisa var. Japonica Nakai, S$_7$), in order to find out the importance as an useful vegetables. In this work 7 wild grasses with different soaking solutions and boiling conditions were examined to investigation the preference factors by sensory evaluation. Results of sensory evaluation for samples showed a significant difference at 1% and 5% level There were high significant differents in samples boiled for different time about astringent taste, bitter taste, perfume, green color and grassy smell at 1% and 5% level. In cooking methods of 7 samples, Namul was liked best and Guk, Salad and Fritter were followed. The condiments which were used for seasoning Namul were Gochujang. Soy Paste, Salt. Gochujang was most preferred.

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