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71.
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Do Hoon Kim Umme Farva Woo Sik Jung Eui Jung Kim Chinho Park 《Korean Journal of Chemical Engineering》2008,25(5):1184-1189
This paper reports an alternative method for the growth of GaN epitaxial layer on (0001) Al2O3 substrate by hot-wall vapor phase epitaxy technique. Tris (N,N-dimethyldithiocarbamato)-gallium (III), Ga(mDTC)3 was introduced as a precursor material for the seed layer formation in the growth of GaN. Optimal growth conditions with
seed layers formed by the Ga(mDTC)3 concentration of 0.047 mol/L were identified: Growth temperature was found to be 850 °C, and optimal distance between the
reactant outlet and substrate was determined to be 12.5 cm. Characterization results showed that this growth method produce
high-crystallinity GaN epitaxial layers at a relatively lower growth temperature compared to the existing growth techniques
and simplify the growth process. 相似文献
74.
75.
Young -Wook Kim Jin -Soo Song Sang -Whan Park June -Gunn Lee 《Journal of Materials Science》1993,28(14):3866-3868
A new, faster process was developed for the fabrication of Nicalon-fibre-reinforced SiC composites by combining polymer solution infiltration (PSI) and chemical vapour infiltration (CVI). The process led to the near-net-shape fabrication of fibre-reinforced ceramic-matrix composites and reduced infiltration time. Typical flexural strength and fracture toughness of these composites were 296 MPa and 10.9 MPa m1/2 at room temperature (RT) and 252 MPa and 9.6 MPa m1/2 at 1000 °C, respectively. The composites exhibited load-carrying capability after crack initiation. 相似文献
76.
RP Allaker KA Young T Langlois R de Rosayro JM Hardie 《Canadian Metallurgical Quarterly》1997,14(4):127-130
Animal bite wounds are amongst the most common types of traumatic injuries in humans. The organisms isolated from these wounds generally reflect the oral flora of the biting animal, and may be fastidious in nature and difficult to identify. This study was undertaken to determine the prevalence of Eikenella corrodens, Actinobacillus actinomycetemcomitans, Porphyromonas and Prevotella spp. in supragingival dental plaque collected from the right maxillary canine and carnassial teeth and the right mandibular canine tooth of dogs. In part one of the study, 30 dogs were used. E. corrodens was found in 62% of these dogs and 44% of individual plaque samples. A. actinomycetemcomitans was not detected in any of the dogs sampled. In part two, 34 dogs were used to determine the prevalence of the black pigmented anaerobic bacilli (Porphyromonas and Prevotella spp.). Porphyromonas gingivalis was present in 68% of these dogs and 47% of individual plaque samples. Prevotella intermedia was present in 44% of the dogs and 23% of individual plaque samples. The recently described Porphyromonas canoris, Porphyromonas salivosa, Porphyromonas cangingivalis, Porphyromonas cansulci, Porphyromonas crevioricanis and Prevotella denticola species were isolated from only 9%, 6%, 3%, 3%, 3% and 3% of dogs respectively. Porphyromonas gingivicanis was not isolated from any of the animals sampled. In conclusion, black-pigmented anaerobic bacilli were isolated from 91% of the animals sampled and therefore constitute a significant risk with respect to bite wound infections. It is also suggested that the prevalence of E. corrodens in wound infections has been underestimated in previous reports because of use of inappropriate techniques for detecting this organism. 相似文献
77.
The purpose of this study was to analyze the symbolization of colors as cultural codes, based on costume colors. In order to study the significance of colors in cultural changes, we carried out a quantitative analysis and interpreted it from the perspective of cultural semiotics. The range of this study was focused on Korean costume colors, over diverse diachronic stages of Korean culture. For this study 1535 color samples were collected, measured with a spectrophotometer, and analyzed quantitatively according their diachronic stages of origin. As a result, red, blue, and yellow were found to be the most frequently used colors during the Chosun Dynasty, a period based on Confucianism. These colors acted as cultural codes with cultural significance. During the Modern times pink, light blue, and black increased in frequency and represented the reception of western culture, the changing sex role of women in society, and utilitarianism. In these days, neutral colors and grayish tones of all colors are the most significant colors of high frequency. The use of such colors is closely related to industrialization, mechanization, functionalism, and the changes of women's sex roles in the societies. They are used as cultural codes, especially to emphasize a rational and masculine image rather than a feminine image. © 2006 Wiley Periodicals, Inc. Col Res Appl, 32, 71–79, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20290 相似文献
78.
明眸晧齿,笑容爽朗,脸部轮廓分明。看到袁泉,马上会有清冽甘甜的感觉,一如她的名字,仿佛夏日里活力天然的一泓清泉。从《春天的狂想》到娃哈哈广告中的美丽少女,袁泉给人的印象一直是青春、健康而甜美的,举手投足,一颦一笑,洋溢着独有的耀眼活力。不久前,这位活力闰女更是担任了“中国女性健康白皮书系列活动”的形象大使。作为宣传女性健康的代言人,袁泉呼吁,要让更多的女性认识到:健康的身体才是美丽人生的根基。[编者按] 相似文献
79.
OBJECTIVE: To estimate the effectiveness of ovarian cancer screening with CA 125 and transvaginal sonography. DESIGN: Decision analysis was used to examine the no-screen compared with the screen strategy. SETTING: Estimates of cancer incidence, survival, and life expectancy were derived from population-based data and clinical series. SUBJECTS: A cohort of 40-year-old women of all races and residing in the United States. INTERVENTIONS: A one-time screening intervention. The criterion standard for diagnosis of ovarian cancer was evaluation with exploratory laparotomy. MAIN OUTCOME MEASURE: Average years of life expectancy gained by women in the screened group. RESULTS: Screening for ovarian cancer with a combination of CA 125 and transvaginal sonography increases the average life expectancy in the population by less than 1 day. CONCLUSIONS: Given the limited effect on overall life expectancy, it is unlikely that mass screening for ovarian cancer with CA 125 and transvaginal sonography would be an effective health policy. 相似文献
80.
Raybon G. Young M.G. Koren U. Miller B.I. Chien M. Zirngibl M. Dragone C. Froberg N.M. Burrus C.A. 《Electronics letters》1995,31(14):1147-1149
Five wavelength multiplexed pulse streams are generated in an integrated 16×1 laser modulator array by sinusoidally driving five of the potential 16 electroabsorption modulators. At a repetition rate of 2.5 GHz, near transform-limited pulses spaced in wavelength over 7.6 nm are observed. Pseudorandom coding of one channel is achieved by applying an electrical RZ data signal to the modulator 相似文献