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The intrinsic instabilities of fluid flow occured in the melt of Czochralski crystal growth system

  • Yi, Kyung-Woo;Koichi Kakimoto;Minoru Eguchi;Taketoshi Hibiya
    • Proceedings of the Korea Association of Crystal Growth Conference
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    • 1996.06a
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    • pp.179-200
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    • 1996
  • The intrinsic instabilities of fluid flow occurred in the melt of the Czochralski crystal growth system Czochralski method, asymmetric flow patterns and temperature profiles in the melt have been studied by many researchers. The idea that the non-symmetric structure of the growing equipment is responsible for the asymmetric profiles is usually accepted at the first time. However further researches revealed that some intrinsic instabilities not related to the non-symmetric equipment structure in the melt could also appear. Ristorcelli had pointed out that there are many possible causes of instabilities in the melt. The instabilities appears because of the coupling effects of fluid flow and temperature profiles in the melt. Among the instabilities, the B nard type instabilities with no or low crucible rotation rates are analyzed by the visualizing experiments using X-ray radiography and the 3-D numerical simulation in this study. The velocity profiles in the Silicon melt at different crucible rotation rates were measured using X-ray radiography method using tungsten tracers in the melt. The results showed that there exits two types of fluid flow mode. One is axisymmetric flow, the other is asymmetric flow. In the axisymmetric flow, the trajectory of the tracers show torus pattern. However, more exact measurement of the axisymmetrc case shows that this flow field has small non-axisymmetric components of the velocity. When fluid flow is asymmetric, the tracers show random motion from the fixed view point. On the other hand, when the observer rotates to the same velocity of the crucible, the trajectory of the tracer show a rotating motion, the center of the motion is not same the center of the melt. The temperature of a point in the melt were measured using thermocouples with different rotating rates. Measured temperatures oscillated. Such kind of oscillations are also measured by the other researchers. The behavior of temperature oscillations were quite different between at low rotations and at high rotations. Above experimental results means that the fluid flow and temperature profiles in the melt is not symmetric, and then the mode of the asymmetric is changed when rotation rates are changed. To compare with these experimental results, the fluid flow and temperature profiles at no rotation and 8 rpm of crucible rotation rates on the same size of crucible is calculated using a 3-dimensional numerical simulation. A finite different method is adopted for this simulation. 50×30×30 grids are used. The numerical simulation also showed that the velocity and flow profiles are changed when rotation rates change. Futhermore, the flow patterns and temperature profiles of both cases are not axisymmetric even though axisymmetric boundary conditions are used. Several cells appear at no rotation. The cells are formed by the unstable vertical temperature profiles (upper region is colder than lower part) beneath the free surface of the melt. When the temperature profile is combined with density difference (Rayleigh-B nard instability) or surface tension difference (Marangoni-B nard instability) on temperature, cell structures are naturally formed. Both sources of instabilities are coupled to the cell structures in the melt of the Czochralski process. With high rotation rates, the shape of the fluid field is changed to another type of asymmetric profile. Because of the velocity profile, isothermal lines on the plane vertical to the centerline change to elliptic. When the velocity profiles are plotted at the rotating view point, two vortices appear at the both sides of centerline. These vortices seem to be the main reason of the tracer behavior shown in the asymmetric velocity experiment. This profile is quite similar to the profiles created by the baroclinic instability on the rotating annulus. The temperature profiles obtained from the numerical calculations and Fourier transforms of it are quite similar to the results of the experiment. bove esults intend that at least two types of intrinsic instabilities can occur in the melt of Czochralski growing systems. Because the instabilities cause temperature fluctuations in the melt and near the crystal-melt interface, some defects may be generated by them. When the crucible size becomes large, the intensity of the instabilities should increase. Therefore, to produce large single crystals with good quality, the behavior of the intrinsic instabilities in the melt as well as the effects of the instabilities on the defects in the ingot should be studied. As one of the cause of the defects in the large diameter Silicon single crystal grown by the

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Progesterone assays as an aid for improving reproductive efficiency in dairy cattle IV. Milk progesterone profiles for monitoring postpartum ovarian activity (Progesterone 농도측정(濃度測定)에 의한 유우(乳牛)의 번식효율증진(繁殖效率增進)에 관한 연구(硏究) IV. 유즙(乳汁)중 progesterone 농도측정(濃度測定)에 의한 분만후(分娩後) 난소기능(卵巢機能) 회복상태(回復狀態)의 검토(檢討))

  • Kang, Byong-kyu;Choi, Han-sun;Choi, Sang-gong;Son, Chang-ho;Kang, Hyun-ku
    • Korean Journal of Veterinary Research
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    • v.34 no.4
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    • pp.881-890
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    • 1994
  • Skim milk progesterone($P_4$) profiles in 74 dairy cows were determind to monitor postpartum ovarian activity by radioimmunoassay. Milk samples were collected from each cow every 5 days from 10 to 90 days postpartum. Signs of estrus were observed twice daily, and status of the ovaries and uterus were examined every 10 days by rectal palpation. Results are summarized as follows: 1. Cows were categorized into five types by the change of skim milk $P_4$ profiles; Type I(normal) : Cyclic changes of skim milk $P_4$ profiles appeared within 20 days postpartum(12 cows, 16.2%), Type II(cycle delayed) : Cyclic changes of skim milk $P_4$ profiles appeared from 21 to 60 days postpartum(39 cows, 52.7%), Type III(cycle ceased with low $P_4$) : Onset of the estrous cycle within 20 days postpartum but ceased later with low levels of $P_4$ (7cows, 9.5%), Type IV(cycle ceased with high $P_4$) : Onset of the estrous cycle within 20 days postpartum but ceased later with high levels(>3.0 ng/ml) of skim milk $P_4$ (4 cows, 5.4%), Type V(acyclicity) : Skim milk $P_4$ concentration remained low(<1.0 ng/ml) until 80 days postpartum(12 cows, 16.2%). 2. Out of the 17 cows classified as the Type III and Type V by skim milk $P_4$ profiles, 13 cows had inactive ovaries and remaining 6 cows had single or multiple follicular cysts in their ovaries by rectal palpation. All 4 cows of Type IV had a persistent corpus luteum in their ovaries. 3. Approximately eighty percent of the cows had begun ovarian activity by 60 days postpartum and 90.6% by 90 days by skim milk $P_4$ profiles, but only 39.2% by 60 days and 71.7% by 90 days had shown visible estrus signs. The mean days from parturition to the first, second and third ovulations determined by skim milk $P_4$ profiles was $28.0{\pm}11.0$, $46.4{\pm}13.3$ and $66.4{\pm}11.5$ days and the visible estrus signs were 9.3%, 38.1%, and 48.6%, respectively. The mean days from parturition to the first visible estrus was $57.2{\pm}15.9$ days. These results indicated that milk $P_4$ profile of each Types by radioimmunoassay can be utilized for monitoring postpartum ovarian and would be useful for the early detection of ovarian dysfunction in dairy cow.

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A Study on the Considerations for Constructing RDA Application Profiles (RDA 응용 프로파일 구축시 고려사항에 관한 연구)

  • Lee, Mihwa
    • Journal of the Korean BIBLIA Society for library and Information Science
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    • v.30 no.4
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    • pp.29-50
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    • 2019
  • This study was to suggest the considerations for application profiles of 2019 revised RDA using literature reviews and case studies according to new RDA that revised in order to reflect the LRM and linked data. First, the additional elements were recommended as the contents of application profiles such as inverse element, broader element, narrow element, domain, range, alternate label name, mapping to MARC, mapping to BIBFRAME, and RDA description examples as new elements as well as element name, element ID, element URL, description method, vocabulary encoding scheme, data provenance element, data provenance value, and notes as the elements that were already suggested by previous researches. Second, RDA rules' representations in forms of flow chart and application profiles through analyzing RDA rules were suggested in order to apply the rules to RDA application profiles to structure the rules in which every element has 4 types of description method, many conditions, and options. Third, the RDA mapping to BIBFRAME was suggested in RDA application profiles because RDA and BIBFRAME are co-related in context of content standard and encoding format, and mapping BIBFRAME and RDA is necessitated for programming BIBFRAME editors with RDA as content standard. This study will contribute to find the methods for constructing RDA application profiles and BIBFRAME application profiles with RDA as content standard.

Latent Profile Analysis of Senior Lifestyle Profile: A stringent study of similarity and differences (시니어세대 라이프스타일 잠재프로파일 유형과 관광 행동 연구)

  • Seo In-seog;Kim Young-mi;Oh Hyun-sung
    • The Journal of the Convergence on Culture Technology
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    • v.9 no.6
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    • pp.899-910
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    • 2023
  • The majority of research on lifestyle has been conducted based on a variable-centered approach. However, over the last decades, there is a growing body of research on lifestyle in terms of a person-centered approach. Hence, this study identifies senior generations' profiles based on the combination of the five realms of lifestyle. More specifically, this study utilized a Latent profile analysis(LPA) to explore both quantitatively and qualitatively distinct types of senior generation' lifestyle profiles. As a result, the five distinct types of senior lifestyle profiles were identified and these five profiles were then contrasted with traveling attitude and behavioral intention(traveling intention). In addition, this study attempted to identify similarity in the patterns of relations with theoretical antecedent, correlate and outcome variables. Results showed that even though senior generation belonging to profile groups pertaining to the high level of all five types of lifestyle were associated with a high level of attitude and behavior intention, there was no differences among the profiles. This means that regardless of the patterns of senor generation lifestyle profiles, there was no similarity. Nevertheless, it should be considered that senior generation consider a security when making a travel ling decision regardless of the patterns of lifestyle profiles. This results suggest that senior generation' traveling satisfaction is more likely obtained with the experience of safety and convenience during their travel. At last, this study discusses some implication tourism theory related to lifestyle, practices and future research on tourism profiles.

Derivation of the refractive index profile equation of K-Na ion-exchange waveguide by a rapid thermal method (급열법에 의한 K-Na 이온교환 도파로의 굴절율 분포식산출)

  • 강승민
    • Proceedings of the Optical Society of Korea Conference
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    • 1990.02a
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    • pp.237-241
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    • 1990
  • A detailed theoretical and experimental study of k-na exchange in soda lime silicate glasses by RTP is presented. Concentration profiles i.e. index profiles are given by complementary error function added Gaussian function. The estimated diffusion coefficient is 1.54${\mu}{\textrm}{m}$2/min.

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Enhancing industrial security of casino business by developing criminal profiling of deviant behaviors in casino (범죄 프로파일링 기법을 활용한 카지노 위반 행동 분석과 카지노 산업보안 증대 방안 연구)

  • Lee, Chang-Hun;Lee, Seung-Hoon
    • Korean Security Journal
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    • no.48
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    • pp.113-146
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    • 2016
  • Criminal profiling is a effective and efficient measure for enhancing industrial security of casino business. Particularly, developing criminal profiling of deviant behaviors in casino will help security management to become more effective and efficient in practical ways. Unfortunately, however, there is lack of empirical profiling study in this regard. To fill the vacuum of literature on this topic, this study was purported to create offender profiles of different types of deviant behaviors in casino based on various theories and techniques in criminal profiling literature, such as investigative psychology, linkage analysis, and behavioral evidence analysis. To fulfill the purposes, this study collected behavioral evidence from 90 casino security officers in South Korea. Offenders' behavioral evidence was analyzed to develop offender profiles of seven different types of deviant behaviors, and then the profiles were compared with each profiles that security officers focus on to identify offenders during their work hours. Results showed that, first, there were unique profiles of each type of seven different categories of deviant behaviors in terms of offenders' ways of speaking and acting, their appearance and attitudes. In addition, this study found that there were some amount of gaps between actual offenders' profiles and profiles that security officers have in mind. Based on the results, this study provided policy implications in terms of managing casino industrial security, education and training for security officers, and future study on casino security.

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Semantic User Profiles Manager based on OSGi (OSGi기반 시맨틱 사용자 프로파일 관리자)

  • Song, Chang-Woo;Kim, Jong-Hun;Chung, Kyung-Yong;Rim, Kee-Wook;Lee, Jung-Hyun
    • The Journal of the Korea Contents Association
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    • v.8 no.8
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    • pp.9-18
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    • 2008
  • Research is being made for users' convenient access to services such as personalized data and contents services. The use of information and the fusion of services in various devices and terminals suggest the necessity to know what personalization mechanism is used to provide high quality contents at a time and place desired by users. Existing mechanisms are not easy to be handled by other service providers because each service provider has different preference and personal information, and are very inconvenient because service users have to set up and manage by themselves. Thus, the present paper proposes a Semantic User Profiles Manager based on OSGi, middleware for the provision and extension of semantic services, in order to manage users' profiles dynamically regardless of service provider. In addition, this paper defines a personalized semantic profile that enables user profiling, ontological domain modeling and semantic reasoning. In order to test the validity of this paper, we implemented semantic profiles into a bundle running based on OSGi. When users enter the range of the service area and use various devices, the semantic service matches in correspondence with semantic user profiles. The proposed system can easily extend the matching of services to user profiles and matching between user profiles or between services.

Postprandial Asymptomatic Glycemic Fluctuations after Gastrectomy for Gastric Cancer Using Continuous Glucose Monitoring Device

  • Ri, Motonari;Nunobe, Souya;Ida, Satoshi;Ishizuka, Naoki;Atsumi, Shinichiro;Hayami, Masaru;Makuuchi, Rie;Kumagai, Koshi;Ohashi, Manabu;Sano, Takeshi
    • Journal of Gastric Cancer
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    • v.21 no.4
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    • pp.325-334
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    • 2021
  • Purpose: Although dumping symptoms are thought to involve postprandial glycemic changes, postprandial glycemic variability without dumping symptoms remains poorly understood due to the lack of a method that allows the easy and continuous measurement of blood glucose levels. Materials and Methods: Patients having undergone distal gastrectomy with Billroth-I (DG-BI) or Roux-en-Y reconstruction (DG-RY), total gastrectomy with RY (TG-RY) and pylorus preserving gastrectomy (PPG) for gastric cancer 3 months to 3 years prior, diagnosed as pathological stage I or II, were prospectively enrolled from March 2018 to January 2020. The interstitial tissue glycemic levels were measured every 15 min, up to 14 days by continuous glucose monitoring. Moreover, using a diary recording the diet and symptoms, asymptomatic glucose profiles without sugar supplementation within 3 h postprandially were compared among the four procedures. Results: A total of 40 patients were enrolled, 10 patients for each of the four procedures. There were 47 glucose profiles with DG-BI, 46 profiles with DG-RY, 38 profiles with TG-RY, and 46 profiles with PPG. PPG showed the slowest increase with a subsequent gradual decrease in glucose fluctuations, without hyperglycemia or hypoglycemia, among the four procedures. In contrast, TG-RY and DG-RY showed spike-like glycemic variability, sharp rises during meals, and rapid drops. The glucose profiles of DG-BI were milder than those of RY. Conclusions: The asymptomatic glycemic changes after meals differ among the types of surgical procedures for gastric cancer. Given the mild glycemic fluctuations in PPG and the glucose spikes in TG-RY and DG-RY, pylorus preservation and physiological reconstruction without changes in food pathways may optimize postprandial glucose profiles after gastrectomy.