• Title/Summary/Keyword: diffusion pattern

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Interface formation between $MgF_2$ and Si(111) studied by LEED, AES, and TPD

  • Y.S. Chung;J.Y. Maeng;Kim, Sehun
    • Proceedings of the Korean Vacuum Society Conference
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    • 1999.07a
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    • pp.183-183
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    • 1999
  • The phases and interface formation of MgF2 on Si(111) were studied by using LEED, AES, and TPD. When thick MgF2 film was deposited on the Si(111) surface at RT뭉 annealed at higher temperatures, a sequence of LEED patterns (no LEED pattern $\longrightarrow$1$\times$1$\longrightarrow$3$\times$1$\longrightarrow$7$\times$7) was observed. On the 1$\times$1 model in which Mg adsorbs on T4 site and F on H3 site could explain the simultaneous desorption of SiF2 and Mg. When thin MgF2 film was deposited, and initial $\alpha$-$\times$1 phase transforms to 3$\times$3 and $\beta$-1$\times$1 by thermal annealing with a slow evaporation of F and diffusion of Mg into the surface. the 3$\times$3 surface changes to ${\gamma}$-1$\times$1 by the selective desorptioon of F under e-beam irradiation and subsesquently to a Mg-induced {{{{ SQRT { 3} }}}} structure by annealing at $600^{\circ}C$.

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A Study of Comparing and Analyzing Electric Vehicle Battery Charging System and Replaceable Battery System by Considering Economic Analysis (경제성을 고려한 전기자동차 충전시스템과 배터리 교체형 시스템의 비교분석 연구)

  • Kim, Si-Yeon;Hwang, Jae-Dong;Lim, Jong-Hun;Song, Kyung-Bin
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.9
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    • pp.1242-1248
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    • 2012
  • Electric vehicle usage is currently very low, but it will be increase with development of electric vehicle technology and a good government policy. Moreover in 2020, advanced electric vehicle manufacturing system will give high performance for its price and mass production. Electric vehicle will become widespread in Korea. From an operational and a planned viewpoint, the electric power demand should be considered in relation to diffusion of electric vehicles. This paper presents the impact of the various battery charge systems. A comparison is performed for electric vehicle charging methods such as, normal charging, fast charging, and battery swapping. In addition, economic evaluation for the replaceable battery system and the quick battery charging system is performed through basic information about charging Infrastructure installation cost. The results of the evaluation show that replaceable battery system is more economical and reliable in side of electric power demand than quick battery charging system.

Investigation of Ventilation Efficiency for the Natural Gas High Pressure Release in an Underground Valve Station (지하 공급관리소내 천연가스 고압분출시 환기효율성 검증)

  • Ha J. M.;Lee J. H.;Sung W. M.
    • Journal of the Korean Institute of Gas
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    • v.6 no.1 s.17
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    • pp.74-80
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    • 2002
  • This study was carried out for the purpose of safety evaluation about the ventilation system (according to the structure of confined room, the position and size of vent window, the amount of blowing air, e.t.c.), which is equipped in one of KOGAS underground valve stations. Particularly, the effect of the fans placed in the upper region was focused in detail. Numerical simulation was conducted in order to predict the features of flow pattern and the diffusion of natural gas concentration. This work examined the ventilation system and resulted in proposing an optimal design of ventilation system.

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Creative Direction for Maison Margiela - John Galliano as a Case Study - (메종 마르지엘라의 크리에이티브 디렉션에 관한 고찰 - 존 갈리아노를 중심으로 -)

  • Lee, Hyun-Jung;Yim, Eun-Hyuk
    • The Korean Fashion and Textile Research Journal
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    • v.24 no.2
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    • pp.173-182
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    • 2022
  • As consumption pattern and fashion communication become digitalized, fashion houses are being inherited by creative directors owing to their expanding role. While the roles and responsibilities of creative directors have been changing extensively along with the dynamic nature of the fashion industry, researches on creative directions have mostly focused on luxury brands. This study examined the creative direction of John Galliano for Maison Margiela, a conceptual brand to be maintained by a creative director. To analyze this, the authors established a creative direction analysis model constituting five elements: brand heritage, trend, democratization, brand status, and persona, drawing on the luxury brand architecture by Kapferer and Bastien. Thus, Galliano has maintained anonymity as a heritage of Maison Margiela, expanding the existing Replica lines, and introduced fashion shows focusing on current issues or social phenomena. As a democratization strategy, he directed the brand to associate with more popular brands or expanded diffusion lines to secure broader customer base, while demonstrating couturier-like showmanship in the media and establishing his own persona. His direction for Maison Margiela recreates and expands brand heritage by transforming the brand philosophy. Therefore the new creative direction communicates with the wider public and diversifies customer bases through democratization strategies, while building Galliano's own persona.

Experimental study on the leakage behavior of aerosol particles in capillary tubes

  • Wang Hui;Sun Zhongning;Xing Ji;Li Yuchen;Gu Haifeng
    • Nuclear Engineering and Technology
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    • v.56 no.11
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    • pp.4601-4610
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    • 2024
  • The leakage rate of aerosol particles is one of the most important parameters for source term evaluation of containment in severe accidents. In this study, gas leakage characteristics experiments were conducted on capillaries with different inner diameters and tube lengths under different pressure differential conditions. The effects of upstream and downstream pressure differential, capillary tube diameter, tube length, aerosol particle size, whether condensation or not, and release time on aerosol leakage rate were studied. The results show that when the pressure difference between the two ends of the capillary is greater than 0.2 MPa, the leakage rate of the capillary shows a pattern of first increasing and then decreasing with the increase of the pipe diameter; The influence of aerosol particle size on leakage rate mainly affects the inertial deposition effect, which increases with the increase of particle size, leading to a decrease in leakage rate; The condensation effect of steam in capillaries can lead to enhanced effects such as condensate capture, thermophoresis, and diffusion electrophoresis, which have a positive strengthening effect on the retention of aerosol particles.

A geographical study of the Korean Tobacoo forming region (韓國 煙草載培地域의 地理學的 硏究)

  • ;Kim, Kwang Ja
    • Journal of the Korean Geographical Society
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    • v.21
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    • pp.16-37
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    • 1980
  • The purpose of this study is to clarify how the Korean tobacco farming region has been geographically formed by natural and cultural environments, and to examine and cultural environments, and to examine whether it can be recognized as a major part of agricultultural regions. The questions asked in this study are associated with the spatial diffusion of tobacco cultivation, the patterns and processes of the farming region from 1900 to 1960, and the regional characteristics of the concentrated farming area since 1960. The study is inductively approached and most data used were collected from old records and field works. The delineation of the tobacco farming region was derived by applying the concept of the uniform region. Tobacco was introduced through Japan during the years of Kwang Hae Kun (1616-1622). According to the old records, three places, Waekwan, Dongrae, and Ulsan, were the first tobacco raising areas. In the 1700's the well-known tobacco farming regions were scattered all around the nation in places like Jinan, Samdeung, Seongcheon, Gangdong, Yeongweol and Yeongyang. This distributon pattern suggests that tobacco farming in Korea developed spatially along main traffic routes before the 1700's. Untill the 1920's the pattern of tobacco regions was relatively static. Since the 1920's, it has shown a pattern of concentration in the Choongbuk province, where the new highly productive yellow tobacco has been introduced. It was not until the 1960's that yellow tobacco instead of the native variety came to be cultivated all over the country. In the 1960's, the tobacco farming region tended to be concentrated and localized in north western Choongnam, northern Cheonbuk, Choongbuk, and Kyeongbuk including Cheongsong, Andong, and Yeongyang. Since 1970, tobacco production has declined in some of the former major areas of cultivation in terms of its density, while there have appeared highly concentrated areas in Cheongsong and Andong, centered around Yeongyand. There has also emerged a secondary major concentrated area along the coast including such places as Kochang, Yeongkwang and Mooan. The appearance of the Yeongyang tobacco area as the most important core region can be described as follows; at first this area has the disadvantage of being in competition with other places for selling cash crops besides tobacco, because it is located in a mountain zone and it is far from the major metropolises of Seoul and Pusan. Thus has been formed the farming mentality that agricultural management makes the most profit on farming tobacco because tobacco is stable in price and selling routes. As a result of this longstanding belief, these areas (Yeongyang, Cheongsong and Andong) have developed into tobacco concentrated regions. Finally, the tobacco concentrated regions of Korea have changed through time. The factors affecting this change have been the kind of tobacco grown, the monopoly system, agricultural techniques and the expansion of arable land through the clearing of slopes. In conclusion, the research indicates that the localized and concentrated patterns of tobacco cultivation are geographically typical. Thus, recognition of tobacco farming region is important to understanding the agricultural region of Korea as a whole.

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Qualitative and Quantitative Magnetic Resonance Imaging Phenotypes May Predict CDKN2A/B Homozygous Deletion Status in Isocitrate Dehydrogenase-Mutant Astrocytomas: A Multicenter Study

  • Yae Won Park;Ki Sung Park;Ji Eun Park;Sung Soo Ahn;Inho Park;Ho Sung Kim;Jong Hee Chang;Seung-Koo Lee;Se Hoon Kim
    • Korean Journal of Radiology
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    • v.24 no.2
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    • pp.133-144
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    • 2023
  • Objective: Cyclin-dependent kinase inhibitor (CDKN)2A/B homozygous deletion is a key molecular marker of isocitrate dehydrogenase (IDH)-mutant astrocytomas in the 2021 World Health Organization. We aimed to investigate whether qualitative and quantitative MRI parameters can predict CDKN2A/B homozygous deletion status in IDH-mutant astrocytomas. Materials and Methods: Preoperative MRI data of 88 patients (mean age ± standard deviation, 42.0 ± 11.9 years; 40 females and 48 males) with IDH-mutant astrocytomas (76 without and 12 with CDKN2A/B homozygous deletion) from two institutions were included. A qualitative imaging assessment was performed. Mean apparent diffusion coefficient (ADC), 5th percentile of ADC, mean normalized cerebral blood volume (nCBV), and 95th percentile of nCBV were assessed via automatic tumor segmentation. Logistic regression was performed to determine the factors associated with CDKN2A/B homozygous deletion in all 88 patients and a subgroup of 47 patients with histological grades 3 and 4. The discrimination performance of the logistic regression models was evaluated using the area under the receiver operating characteristic curve (AUC). Results: In multivariable analysis of all patients, infiltrative pattern (odds ratio [OR] = 4.25, p = 0.034), maximal diameter (OR = 1.07, p = 0.013), and 95th percentile of nCBV (OR = 1.34, p = 0.049) were independent predictors of CDKN2A/B homozygous deletion. The AUC, accuracy, sensitivity, and specificity of the corresponding model were 0.83 (95% confidence interval [CI], 0.72-0.91), 90.4%, 83.3%, and 75.0%, respectively. On multivariable analysis of the subgroup with histological grades 3 and 4, infiltrative pattern (OR = 10.39, p = 0.012) and 95th percentile of nCBV (OR = 1.24, p = 0.047) were independent predictors of CDKN2A/B homozygous deletion, with an AUC accuracy, sensitivity, and specificity of the corresponding model of 0.76 (95% CI, 0.60-0.88), 87.8%, 80.0%, and 58.1%, respectively. Conclusion: The presence of an infiltrative pattern, larger maximal diameter, and higher 95th percentile of the nCBV may be useful MRI biomarkers for CDKN2A/B homozygous deletion in IDH-mutant astrocytomas.

Antimicrobial Resistance Patterns and Resistance genes assay of Shigella sonnei Isolated in Korea for Five Years (최근 5년 동안 국내에서 분리된 Shigella sonnei의 항균제 내성 유형과 내성유전자형 분석)

  • Huh, Wan;Lee, Sang-Jo;Kwon, Gi-Seok;Jang, Jong-Ok;Lee, Jung-Bok
    • Korean Journal of Microbiology
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    • v.43 no.1
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    • pp.31-39
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    • 2007
  • This study has been carried out for investigating the relatedness of representative 135 Shigella sonnei strains isolated from 2000 to 2004 by using biotyping and antimicrobial resistance. All strains showed typical biochemical characterisics of Shigella strain. Among 135 strains,79 (58.5%) strains were biotype "g",54 (40.0%) strains were biotype "a" and 2 (1.5%) strains were biotype "e". The results of susceptibility test against 16 antimicrobial agents were like this. Most of strains were susceptible to AN, CIP, C and GM. 129 (95.6%) strains were resistant to SXT, 126 (93.3%) strains were resistant to TE and 122 (90.4%) strains were resistant to SM. One hundred thirty two (97.8%) strains were resistant to more than two antimicrobial agents. R28 type (antimicrobial resistance patterns 28: resistant to AM, SAM, TE, TIC, SXT, K, SM and AmC) were 42 strains (31.1%). The other strains were showed 33 kinds of R patterns. The results of $bla_{TEM}$, sulII, tetA and strA gene detection were coincided with phenotype of antimicrobial resistance by disk diffusion method. But some strains which had sulII and strA genes were not showed the resistance against SXT and SM.

Oropharyngeal Carriage and Antimicrobial Resistance of S. pneumoniae in Children of Seoul (서울 지역 소아의 구인강에서 폐구균 보균율과 항균제 내성)

  • Kim, Young Kee;Lee, Chang Kyu
    • Pediatric Infection and Vaccine
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    • v.4 no.2
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    • pp.218-224
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    • 1997
  • Purpose: The antimicrobial resistance of S. pneumoniae has encountered with increasing frequency from around the world. In our country, penicillin resistant strains of S. penumococci are rapidly increasing. It has been known that colonized pneumococci in upper respiratory tract cause sinisitis, otitis media, meningitis and pneumonia. We tried to reveal the colonization rate of pneumonocci in upper respiratory tract, their antimicrobial resistance and DNA fingerprinting pattern in normal children. Methods: We got specimens from 117 children of day-care center in Seoul through oropharyngeal swab. After incubation on BAP, optochin test and slide latex agglutination test were used for identification. Antimicobial susceptibility test to penicillin, vancomycin, erythromycin and TMP-SMZ was done with disk diffusion method. Penicillin MIC was gotten through the broth microdilution method. Genotyping of 45 pneumococci was done by rep-PCR using REP1R-Dt and REP2-Dt primer. Results: The carriage rate of pneumococci in the day-care center children was 38%(45/117). The resistance of penicillin, erhthromycin, TMP/SMZ, vancomycin by the disk diffusion method are 89%, 91%, 64% and 0%, respectively. 64% of the isolates showed multiple resistance. 7 types of DNA fingerprinting were gotten and 78% of isolates belonged to three types. Conclusion: We found that the antimicrobial resistance of children attending the day-care center in Seoul was much higher than expected. We assumed that this might be due to their easy and frequent exposure to antimicrobial agents and crowded day-care center environment.

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Sensitivity Analysis of Wake Diffusion Patterns in Mountainous Wind Farms according to Wake Model Characteristics on Computational Fluid Dynamics (전산유체역학 후류모델 특성에 따른 산악지형 풍력발전단지 후류확산 형태 민감도 분석)

  • Kim, Seong-Gyun;Ryu, Geon Hwa;Kim, Young-Gon;Moon, Chae-Joo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.17 no.2
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    • pp.265-278
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    • 2022
  • The global energy paradigm is rapidly changing by centering on carbon neutrality, and wind energy is positioning itself as a leader in renewable energy-based power sources. The success of onshore and offshore wind energy projects focuses on securing the economic feasibility of the project, which depends on securing high-quality wind resources and optimal arrangement of wind turbines. In the process of constructing the wind farm, the optimal arrangement method of wind turbines considering the main wind direction is important, and this is related to minimizing the wake effect caused by the fluid passing through the structure located on the windward side. The accuracy of the predictability of the wake effect is determined by the wake model and modeling technique that can properly simulate it. Therefore, in this paper, using WindSim, a commercial CFD model, the wake diffusion pattern is analyzed through the sensitivity study of each wake model of the proposed onshore wind farm located in the mountainous complex terrain in South Korea, and it is intended to be used as basic research data for wind energy projects in complex terrain in the future.