• Title/Summary/Keyword: Fixed time method

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Evaluation of occlusal strength using T-Scan Novus and Dental prescale II in dental prosthodontic treatments: A case report (보철물 수복 형태에 따른 T-Scan Novus와 Dental prescale II를 이용한 교합력 평가 활용 증례)

  • Su-Hyun Choi;Yu-Sung Choi;Jong-Hyuk Lee;Seung-Ryong Ha
    • The Journal of Korean Academy of Prosthodontics
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    • v.61 no.2
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    • pp.160-178
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    • 2023
  • Diagnosis and analysis of occlusal relationships are important factors in prosthetic treatment. A thorough occlusion analysis and evaluation should be performed before treatment to restore a stable interocclusal relationship. Analysis and evaluation are essential during the treatment process and at regular follow-ups. Recently, with the development of dental equipment and digital processing methods, new quantitative analysis methods that can record the patient's occlusal relationship have been introduced. Among them, the T-Scan Novus (Tekscan Inc., S. Boston, MA, USA) displays the strength of the initial contact point and the occlusal contact point of the teeth using a pressure sensor. With this, occlusal contact time of the teeth, anteroposterior and left-right balance of occlusal force can be compared. The Dental prescale II (GC Co., Tokyo, Japan) scans the occlusal contact point using a pressure-sensing film and analyzes the density of the contact point. It can measure the distribution and strength of the occlusal force of the teeth in the most natural occlusion state. Based on this, appropriate prosthetic treatment (four-unit fixed partial denture, removable partial denture, complete denture, and complete oral restoration cases) was performed according to the area and extent of the patient's tooth loss. The patient's occlusion at the first visit, treatment stage, right after treatment, and regular follow-up were compared and evaluated using a quantitative method for appropriate occlusion analysis using T-Scan Novus and Dental prescale II. This report enhances the understanding of occlusion analysis during prosthetic restoration. The results satisfied both the clinician and patients in terms of function and aesthetics.

Exploring Meaning for Change of Social Awareness of Art Activity (예술활동의 사회적 인식변화를 위한 의미 탐색)

  • Seo, Sang-Gyu;Oh, Kwang-Suk;Sin, Dae-Sik;Hong, Sea-Hee;Sung, Gun-Jae;Jung, Ha-Ni
    • Journal of Korea Entertainment Industry Association
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    • v.13 no.5
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    • pp.167-173
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    • 2019
  • This study aimed to point out the social meaning of acting and art and the change of perception according to the time change. The research method was based on qualitative research through literature review. Based on the findings of this study, the following conclusions should be made. Acting is an art directly linked to the life of an individual. Therefore, the life of an individual is an activity that sublimates his or her life into art through acting. Every activity that we do in our daily life is acting, which is directly related to our talents. In other words, a talented person is recognized as a good actor, and a person with a lack of talent plays the role of an extra person. However, talent is influenced by effort and is also influenced by a given environment. That is, an individual's talent is not fixed but can be changed according to the situation. Education is the area that deals with the possibility of changing these talents. Education has been operating in a variety of ways, but with regard to acting, it has long been centered on apprenticeship education. However, as the 20th century began, systems gradually began to emerge, and in recent years, countries have developed into different educational systems. Therefore, it is necessary to practice the development and operation of various education programs so that the acting and the art are naturally applied in everyday education process and can be applied in daily life.

Significance of tibial intra-tunnel fixation at Arthroscopic ACL Reconstruction with hamstring tendon (Second-look Arthroscopic Evalution) (자가 슬괵건을 이용한 전방 십자인대 재건술시 경골측 골 터널내 고정의 의의 (이차관절경 검사의 평가))

  • Kim, Young-Chang ;Seo, Seung-Suk;Jung, Kyung-Chil;Gwak, Hey-Chul;Kim, Yoon-Jun;Kim, Jin-Seok
    • Journal of the Korean Arthroscopy Society
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    • v.10 no.2
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    • pp.165-172
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    • 2006
  • Purpose: The purpose of this study is to evaluate the effects of intratunnel fixation in the tibial side on the arthroscopic ACL reconstruction with quadruple hamstring tendon at the second look arthroscopy. Materials and Method: From Dec 1999 to May 2005, we arthroscopically reexamined 32 cases who had been done arthroscopic ACL reconstruction with quadruple hamstring tendons. Hamstring tendons of all cases were fixed at femoral side with RigidfixTM. At the tibial side hamstring tendons were fixed only Post-tie (Group I) or Post-tie combined with IntrafixTM (Group II). At the time of second look arthroscopy mean age of cases was 30 years and mean duration for second look arthroscopy was 21.3 months. We analyzed the results with IKDC score, KT-1000 arthrometer under anesthesia, Telos stress radiography, tibial tunnel widening on the radiography and second look arthroscopic findings. Results: Group II had more superior than group I at side to side differences with KT-1000 and Telos stress radiograph, IKDC score, but the differences were insignificant. At arthroscopic evaluation, Group ll also had more superior than group I at graft tension and graft appearance, graft synovialization, but the differences were insignificant. Tibial tunnel widening in the knee AP radiograph was 2.3 mm in Group I and 1.7 mm in Group II and the difference was significant. (P=0.042) Conclusions: Additional procedure of tibial intratunnel fixation in arthroscopic ACL reconstruction with autogenous hamstring tendon significantly prohibited from tibial tunnel widening but clinical results, radiologic joint stability, findings in second look arthroscopy were insignificantly different. We concluded that Post-tie itself induced satisfactory clinical results, joint stability and graft maturation and that tibial tunnel widening did not affect the results.

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Types of tweezers and their culture of use (족집게(鑷)의 유형과 사용 문화)

  • KIM, Jihyeon
    • Korean Journal of Heritage: History & Science
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    • v.54 no.3
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    • pp.4-23
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    • 2021
  • The purpose of this study was to classify the types of tweezers used across time and to examine the social culture of periods through the use of tweezers. Chapter II summarized the terms for tweezers and looked at the use of tweezers in two cases related to the social culture and politics of a period. The first is the use of tweezers for beauty purposes. Men used tweezers as a kind of self-management to maintain their social status and power, and thus they helped develop a wide range of tweezers cultures. People with gray hair are usually old. The perception that we should step down from politics when we are aged has become strong. Therefore, politicians pulled out gray hairs with tweezers to maintain only black hair and show youth, which indicates that their social influence is still strong. The second is the use of tweezers for first aid. Chapter III classified tweezers by type during the Goryeo and Joseon periods. The tweezers are largely divided into basic and composite types. The basic type of tweezers is a form that has been continued since the Three Kingdoms Period and consists of tongs and handles, and a fixed type of tweezers with a fixed ring appeared. Composite tweezers are made by grafting earpick or multipurpose knives. Composite tweezers are all-in-one tweezers with an earpick and an all-in-one knife. Tweezers are usually all-in-one. Among the composite tweezers, rivet separation and ring separation are characterized by separation, unlike the all-in-one tweezers. The method of connecting is divided into rivets and connection rings. The all-in-one tweezers appear only during the Goryeo Dynasty and are characterized by the lifestyle that provides a glimpse of the tastes of contemporary users. The manufacturing takes shape after making a thin metal plate. Decorative techniques are carved on soft metal tweezers, such as silver and bronze with a line, point, and a pressed angle. These tweezers are presumed to have been used by the royal family or aristocrats. However, most tweezers are made of strong bronze or iron. Therefore, the majority of simple X-shaped patterns are sampled or without patterns. The biggest reason why there are such diverse types of tweezers is that the culture of tweezers was widespread regardless of the times. In addition, the basic type of tweezers has been used since the Three Kingdoms Period and has been modified and used together as necessary because the shape of tweezers is a practical daily tool. Study of metal crafts have been limited to royal objects and Buddhist crafts. We hope that research on everyday tools such as tweezers will continue to serve as an opportunity to examine the social and cultural aspects of the times in various ways.

Stress Variation Characteristics of Temporary Fixed Steel Rod in FCM Bridge Construction Method (FCM 교량 가설 공법에서 임시 고정 강봉의 응력 변화 특성 )

  • Hyun-Euk Kang;Wan-Shin Park;Young-Il Jang;Sun-Woo Kim;Hyun-Do Yun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.27 no.3
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    • pp.21-29
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    • 2023
  • In this study, the stress characteristics of temporary fixed steel rods were analyzed in the "temporary fixing system using internal prestressing tension", which is mainly applied to the construction of superstructures by FCM. It was difficult to confirm the changes in initial tensile force in this system because the steel rod was internally connected to the pier and the PSC BOX. Therefore, measurement was performed before and after the completion of each segment using an FBG sensor to measure the change in the micro length of the steel rod. The results of the analysis showed that 75% to 90% of the maximum vertical contraction of the steel rod that occurred until the completion of the cantilever segment occurred in the fixing ~ 1segment, and the maximum loss of initial prestressing force was 39%. Such excessive loss of tension force to 1 segment means that tension is needed to improve the precision of construction during the fixation, and re-tension is needed to secure stability for conduction of cantilever segments after the completion of 1segment. In the 2 ~ last segment, the stress of the steel rod decreased gradually, and in the summer, the decrease in stress tended to partially recover due to the increase in the length of the steel rod corresponding to the increase in the vertical volume of PSC BOX. The dominant factor in the stress change in 2~ last segment in this phenomenon is judged to be the change in the length of the steel rod according to the temperature. Unlike the change in length, the relaxation was 1.2-2.7%, which was mostly offset by the opposite stress corresponding to the temperature stress. Therefore, a plan was proposed to improve the internal stress, such as adjusting the fixation time.

Transfer Learning using Multiple ConvNet Layers Activation Features with Principal Component Analysis for Image Classification (전이학습 기반 다중 컨볼류션 신경망 레이어의 활성화 특징과 주성분 분석을 이용한 이미지 분류 방법)

  • Byambajav, Batkhuu;Alikhanov, Jumabek;Fang, Yang;Ko, Seunghyun;Jo, Geun Sik
    • Journal of Intelligence and Information Systems
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    • v.24 no.1
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    • pp.205-225
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    • 2018
  • Convolutional Neural Network (ConvNet) is one class of the powerful Deep Neural Network that can analyze and learn hierarchies of visual features. Originally, first neural network (Neocognitron) was introduced in the 80s. At that time, the neural network was not broadly used in both industry and academic field by cause of large-scale dataset shortage and low computational power. However, after a few decades later in 2012, Krizhevsky made a breakthrough on ILSVRC-12 visual recognition competition using Convolutional Neural Network. That breakthrough revived people interest in the neural network. The success of Convolutional Neural Network is achieved with two main factors. First of them is the emergence of advanced hardware (GPUs) for sufficient parallel computation. Second is the availability of large-scale datasets such as ImageNet (ILSVRC) dataset for training. Unfortunately, many new domains are bottlenecked by these factors. For most domains, it is difficult and requires lots of effort to gather large-scale dataset to train a ConvNet. Moreover, even if we have a large-scale dataset, training ConvNet from scratch is required expensive resource and time-consuming. These two obstacles can be solved by using transfer learning. Transfer learning is a method for transferring the knowledge from a source domain to new domain. There are two major Transfer learning cases. First one is ConvNet as fixed feature extractor, and the second one is Fine-tune the ConvNet on a new dataset. In the first case, using pre-trained ConvNet (such as on ImageNet) to compute feed-forward activations of the image into the ConvNet and extract activation features from specific layers. In the second case, replacing and retraining the ConvNet classifier on the new dataset, then fine-tune the weights of the pre-trained network with the backpropagation. In this paper, we focus on using multiple ConvNet layers as a fixed feature extractor only. However, applying features with high dimensional complexity that is directly extracted from multiple ConvNet layers is still a challenging problem. We observe that features extracted from multiple ConvNet layers address the different characteristics of the image which means better representation could be obtained by finding the optimal combination of multiple ConvNet layers. Based on that observation, we propose to employ multiple ConvNet layer representations for transfer learning instead of a single ConvNet layer representation. Overall, our primary pipeline has three steps. Firstly, images from target task are given as input to ConvNet, then that image will be feed-forwarded into pre-trained AlexNet, and the activation features from three fully connected convolutional layers are extracted. Secondly, activation features of three ConvNet layers are concatenated to obtain multiple ConvNet layers representation because it will gain more information about an image. When three fully connected layer features concatenated, the occurring image representation would have 9192 (4096+4096+1000) dimension features. However, features extracted from multiple ConvNet layers are redundant and noisy since they are extracted from the same ConvNet. Thus, a third step, we will use Principal Component Analysis (PCA) to select salient features before the training phase. When salient features are obtained, the classifier can classify image more accurately, and the performance of transfer learning can be improved. To evaluate proposed method, experiments are conducted in three standard datasets (Caltech-256, VOC07, and SUN397) to compare multiple ConvNet layer representations against single ConvNet layer representation by using PCA for feature selection and dimension reduction. Our experiments demonstrated the importance of feature selection for multiple ConvNet layer representation. Moreover, our proposed approach achieved 75.6% accuracy compared to 73.9% accuracy achieved by FC7 layer on the Caltech-256 dataset, 73.1% accuracy compared to 69.2% accuracy achieved by FC8 layer on the VOC07 dataset, 52.2% accuracy compared to 48.7% accuracy achieved by FC7 layer on the SUN397 dataset. We also showed that our proposed approach achieved superior performance, 2.8%, 2.1% and 3.1% accuracy improvement on Caltech-256, VOC07, and SUN397 dataset respectively compare to existing work.

A Study on Development of Energy Education Materials for Middle School Students (중학교용 에너지 교육 자료 개발 연구)

  • 최돈형;이양락
    • Hwankyungkyoyuk
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    • v.7 no.1
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    • pp.46-87
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    • 1994
  • Our country has been consuming a huge amount of energy in the course of industrialization and its demand is expected to increase enormously in the future. However, the deposits of energy resources are so limited that the settlement of energy problem comes up the essential subject. To solve the energy problem, it is requested that new resources to gain energy stably should be developed and also energy should be economized and used effectively. The effective use of energy and an the wisdom of economy in energy are requested to everybody and these things should be habitualized from very young age through education. Nevertheless, almost every school in our country hasn’t been concerned about energy education. Even though they have a concern, they are very short of the energy education materials and the quality of the materials is not so good. Therefore it is very meaningful to the settlement of energy problem of the country to make the students who will lead our country to make the students who will lead our country in the future realize the seriousness of energy problem and to provide them the necessary knowledge and methods to solve this problem so that they practice those things in everyday life. Having these necessities, this research, supported by The Korea Energy Management Corporation(KEMCO), was performed for 8 months from April 17, 1994 to December 17, 1994. Many peoples participated in this study such as 30 staffs of researchers and authors, 5 staffs of photographers and illustrators, and 3 VCR program producers developing an energy education material set for middle school students that includes a printed material for student, a diskette for computer simulation, a teacher's guidebook, VCR material and its guidebook. The following main development direction was established : First, the material for student should be consisted of units that let students know the seriousness of energy problem. Second, the focus should be put on the necessary method and practice to economize energy actually in real life based on the basic knowledge learned in elementary school. Third, material for student should be consisted of modules to be student activity-oriented teaching-learning rather than lecture-oriented one. The activity, to maximize student's interests, should be presented in various forms such as experiments, investigation, play, data interpretation, computer simulation, visits, expression and appreciation, etc. To develop the energy education materials for middle school students, a research plan was made first. After literature review about domestic and foreign energy education materials, several research trips home and abroad, and discussion meetings, the basic theory of energy education such as the principle, objective, contents, teaching-learning method, and evaluation method was established. Material for student was developed through the following procedures : The activities in the existing energy education materials were analysed and were divided into four categories related to energy using places of home, school, community, and country, and which were again divided into three categories related to time of past, present, and future, Considering these division, nine modules which are structure units of material for student were chosen, Each module comprises 2-4 activities. Totally 31 activities were designed in this way. The syllabi were made out for each activity and writing was asked for to experts related to each activity after several discussions and revision. To complement the draft, another several discussions and revision were also made on it and then pictures and illustrations were asked for. All these procedures complete the material for student, titled ; Energy Inquiry of Middle School Students', which totals 129 pages and is all in color. As the manuscript of material for student was fixed, writing for teacher's guidebook was asked for to the same writers. The draft of teacher's guidebook was also complemented through the several concentrated works and discussions. Teacher's guidebook focused on the teaching-learning principle and methods of energy education and on the concrete instruction cases for effective instruction of material for student. It is organized with two parts : the one is 'general outline' which introduces theoretical contents and the other is 'details' which are practically helpful to teaching-learning. It is totally 131 pages including both 'general outline' and 'details'. The VCR material and its guidebook consist of contents that cultivate the good attitude trying to economize energy and raise student's interests with a purpose of strong motivation to recognize the necessity of economy and practice it. After establishing development direction of VCR material through discussion meetings and research trips, its script was made by relevant experts. Then the script was also reviewed two times. The drafted VCR material made by a video material developing expert was examined and modified by previews twice. After completion of VCR material, the VCR guidebook was made. All these procedures led to the development of VCR material which runs 20 minutes in VHS type. The VCR guidebook shows a production purpose of the program, structure of contents, evaluation methods, and contents of the program in detail to give help to instructors when they use this VCR material, When these energy education materials are used, it is desirable that the VCR material should be presented first to induce student's motive, and then material for student is introduced Since the material for student is composed of activity-oriented modules and each module is independent one another in general, and each activity is, too. the necessary module or activity can be chosen and utilized in any order according to school or class conditions. This energy education materials will contribute to the development of student's ability to solve energy problem in everyday life and teacher's ability to teach the fundamental knowledge and method in solving energy problem.

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Content and Meaning of Royal Garden Sightseeing Event in Pyoam's 「Hogayugeumwongi」 (표암(豹菴)의 「호가유금원기(扈駕遊禁苑記)」에 나타난 궁원 유람행사의 내용과 의미)

  • Hong, Hyoung-Soon
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.32 no.2
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    • pp.1-11
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    • 2014
  • This study aimed at investigating the content and meaning of royal garden(宮苑) sightseeing event in Pyoam Gang, sehwang's "Hogayugeumwongi" As the research method, descriptive research method was used, which is to consider and interpret the content and meaning in the historical records. Research results are summarized as follows. 1. "Hogayugeumwongi", which recorded the event that the King personally guided and explained the palace to the vassals, is a very precious historical records in Korean landscape gardening cultural history. Such thing is unprecedented in Joseon Dynasty as well as China. 2. The person who recorded this event was famous for shi seo hwa samjeol in the time, and the point that he was Pyoam, who was appreciated as 'the head(總帥) of artistic and literary circles(藝苑)', adds more value to the future generations. 3. The characteristic of this sightseeing event was to praise the vassals' labor, who contributed to the completion of Kyujanggak, to establish King Jongjo's direct rule in the early period of seizure of power, and eojin(御眞) dosa(圖寫), etc., which expressed the King's dignity. Jongjo utilized Geumwon, a forbidden place in the palace, to give a special privilege to the vassals' effort, who took a great part in realizing his political ideal. 4. One of sightseeing lines toward the backyard of Changdeok Palace could be identified. Though the sightseeing lines toward the backyard were not fixed, however this might be the best sightseeing line which Jongjo intentionally chose to enjoy that day's flavor of autumn. 5. The characteristic of this event was informal and somewhat extemporary 'sightseeing'. Therefore, it is considered, that day's event was relatively private and free 'play(遊)', while 'sanghwaeojoyeon(賞花漁釣宴)', which Jongjo gave to the vassals middle after his reign, was a royal 'banquet', which prepared frames, such as event holding time and form, qualification for participation, e.g. flower viewing, fishing, writing poems, etc. This research has a significance that it considered the content and meaning in historical records including the front and the rear context that "Hogayugeumwongi" was written through the consideration of related historical materials. "Hogayugeumwongi" can be utilized as a material for storytelling with regard to royal garden sightseeing in future as a valuable cultural content, also, follow-up study on this is necessary.

THE ATTITUDE SURVEY OF ORTHODONTIC PATIENTS' PARENTS AT CHONBUK NATIONAL UNIVERSITY HOSPITAL, THE DEPARTMENT OF PEDIATRIC DENTISTRY (전북대학교병원 소아치과에 내원한 교정환자 보호자들의 의식에 관한 설문조사)

  • So, Yu-Ryeo;Baik, Byeong-Ju;Kim, Jae-Gon;Yang, Yeon-Mi;Lee, Young-Hun
    • Journal of the korean academy of Pediatric Dentistry
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    • v.35 no.3
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    • pp.487-493
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    • 2008
  • Recently, in proportion to the remarkable development of dentistry and income increases it is growing more and more a concern about changed awareness in appearance. In this study, it had a grasp of the purpose for university hospital visiting, the motive of the commencement for orthodontic treatment and a method of the treatment as well as term. Based on these, the aim of this study is to keep more of the information between parent and doctors for mutual understanding and to grasp the characteristics for the needs of orthodontic treatment. In order to conduct researches, there has made a survey of 150 persons among orthodontic patients' parents who visit CBNU hospital, the pediatric dentistry. The study has found the results like these. 1. There was a question about the reason to visit CBNU hospital in the department of pediatric dentistry for orthodontic treatment. 52.1% of respondents, the survey found, were more likely to receive a good medical service. 25% of them were counselled from a relative or an acquaintance. 16.7% of them were recommended by another dental clinic. 2. There was a question about the expected orthodontic treatment period, when at first hospital visiting. 37.5% of the respondents answered that it was a 'more than 2 years', 12.5% of them said 'from 12 months to 18 months'. 3. There was a question about the reason to receive orthodontic treatment. 58.3% of the respondents, the survey found, answered the reason was parents' concern about the malocclusion of their children, 12.5% of them said a the orthodontic problem pointed out by entourages. 4. There was a question about the method of orthodontic treatment for patients who visit the department in pediatric dentistry. 41.7% of the respondents said that it was used as 'an intra-oral fixed appliance', 29.2% of them said 'an intra-oral removable appliance', 2.1% of them said 'an extra-oral appliance', 5. There was a question about the waiting time for treatment after a dental appointment. 60.4% of the respondents said 'from 5 minutes to 10 minutes', 4.1% of them said 'from 15 minutes to 30 minutes'. There was a question about the extent of an acceptable waiting time. It was answered to 'from 5 minutes to 10 minutes' by 60.4% of them, 2.1% of them said 'from 15 minutes to 30 minutes'.

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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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