• 소성∙가공
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• 제15권1호
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• pp.15-20
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• 2006

The rapid thermal response (RTR) molding is a novel process developed to raise the temperature of mold surface rapidly to the polymer melt temperature prior to the injection stage and then cool rapidly to the ejection temperature. The resulting filling process is achieved inside a hot mold cavity by prohibiting formation of frozen layer so as to enable thin wall injection molding without filling difficulty. The present work covers flow simulation of thin wall injection molding using the RTR molding process. In order to take into account the effects of thermal boundary conditions of the RTR mold, coupled analysis with transient heat transfer simulation is suggested and compared with conventional isothermal analysis. The proposed coupled simulation approach based on solid elements provides reliable thin wall flow estimation for both the conventional molding and the RTR molding processes.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.1348-1353
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• 2006

In this paper, nonlinear elasto-plastic analysis was performed to investigate the stability of the rapid embankment under undrained condition. The commercial code ABAQUS/Standard was used in the study. Resonant Column test (RC test) results and Ramberg-Osgood model were utilized to simulate the nonlinear behavior of soft clay. Ramgerg-Osgood model was tested whether it simulates the nonlinear behavior of the soil properly in first. Then the analysis result was compared with the previous research results. It was found that the Ramberg-Osgood model matched well with the soil behavior of soft clay in the rapid embankment under undrained condition.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 금형가공,미세가공,플라스틱가공 공동 심포지엄
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• pp.9-12
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• 2005

The rapid thermal response (RTR) molding is a novel process developed to raise the temperature of mold surface rapidly to the polymer melt temperature prior to the injection stage and then cool rapidly to the ejection temperature. The resulting filling process is achieved inside a hot mold cavity by prohibiting formation of frozen layer so as to enable thin wall injection molding without filing difficulty. The present work covers flow simulation of thin wall injection molding using the RTR molding process. In order to take into account the effects of thermal boundary conditions of the RTR mold, coupled analysis with transient heat transfer simulation is suggested and compared with conventional isothermal analysis. The proposed coupled simulation approach based on solid elements provides reliable thin wall flow estimation fur both the conventional molding and the RTR molding processes

• 한국레이저가공학회지
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• 제3권1호
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• pp.21-28
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• 2000

Selective Laser Sintering (SLS) can produce three-dimensional objects directly from a CAD solid model without part-specific tooling. In this study, a simple rapid prototyping through selective laser sintering on brass powder is investigated using a Nd-YAG laser. Experiments are conducted to produce single lines on a powder-packed bed for various process parameters. Also, temperature distribution in the powder bed and the thickness of a melted line are predicted by finite element analysis. In the numerical analysis, the thermal conductivity of the brass powder which is obtained as a function of state and temperature is used.

• Journal of Veterinary Science
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• 제23권6호
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• pp.80.1-80.6
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• 2022

A 10-year-old male neutered Labrador Retriever presented with a history of acute-onset tachypnoea, lethargy and anorexia. The dog was pyrexic, tachypnoeic and dyspnoeic on examination. A rapid antigen test for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) was performed on an oropharyngeal swab and yielded a positive result. SARS-CoV-2 infection was subsequently confirmed by reverse transcription polymerase chain reaction (RT-PCR) analysis. Both of the dog's owners had positive rapid antigen test and RT-PCR analysis results for SARS-CoV-2. Additional diagnostics included computed tomography. Resolution of the dog's clinical signs was achieved with symptomatic treatment.

• 소성∙가공
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• 제19권3호
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• pp.152-159
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• 2010

Rapid mold heating has been recent issue to enable the injection molding of thin-walled parts or micro/nano structures. High-frequency induction is an efficient way to heat mold surface by electromagnetic induction in a non-contact manner, and has been recently applied to the injection molding due to its capability of rapid heating and cooling of mold surface. The present study covers a three-dimensional finite element analysis to investigate heating efficiency and structural safety of the induction heating process of an injection mold. To simulate the induction heating process, an integrated simulation method is proposed by effectively connecting an electromagnetic field analysis, a transient heat transfer analysis and a thermal stress analysis. The estimated temperature changes are compared with experimental measurements for various types of induction coil, from which heating efficiency according to the coil shape is discussed. The resulting thermal stress distributions of the mold plate for various types of induction coils are also evaluated and discussed in terms of the structural safety.

• 대한치과교정학회지
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• 제21권2호
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• pp.447-455
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• 1991

This research was carried out in order to study the effects of Rapid Maxillary Expansion on maxilla and it's surrounding skeletal structures. The sample for this study consists of 14 patients who were in retention period after rapid maxillary expansion. Following results were obtained after performing comparative analysis of cephalograms taken before and after rapid maxillary expansion. 1. In almost every cases, inferior displacement of palatal planes with concurrent changes in their inclination were observed. 2. Changes in the inclination of palatal plane can be categorized into inferiorty inclined group, superiorly inclined group and constant group in relation to the states before rapid masillary expansion. 3. Decrease in < Se-FMN/PMV and increase in < Se-FMN-A were evident in the superiorly inclined group and vice versa for the inferiorly inclined group.

• Journal of the Korean Data and Information Science Society
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• 제18권3호
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• pp.679-688
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• 2007

We select the 'rapid reading and comprehension method' to promote the reading skill, and want to apply it to students to study how their reading speed and comprehension improves. For this purpose, in this paper, we define reading as an accurate and quick ability to process information, and the object of this research is to verify a scheme to improve the reading skill, which is called the 'rapid reading and comprehension method - reading based on this method means fast reading as well as an accurate understanding which increases the amount of information received'. For data collection, we selected four primary school in the Kimje city. We found out validation the effective improvement of the reading ability by the 'rapid reading and comprehension method program'. The students' reading speed was enhanced by the rapid reading training and the comprehension ability increased as well.

• 한국세라믹학회지
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• 제12권2호
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• pp.21-25
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• 1975

As the major alumina source, domestic alunite was applied to synthesize the clinker for rapid hardening cement. The main minerals of the clinker were found to be C3S, C11A7-CaF2 and some C4AF by means of chemical treatment, x-ray diffraction analysis and microscopic observation. Rapid hardening cement was made of the clinker by adding suitable amount of hemi-hydrite and anhydrite. The setting time of the cement was regulated with citric acid as setter.

• 한국치위생학회지
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• 제18권3호
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• pp.269-280
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• 2018

Objectives: The purpose of this study was to investigate the change in the posture of dental hygiene students and clinical dental hygienists when implementing dental scaling before and after posture correction training using the rapid upper limb assessment (RULA) method and 3D motion analysis. Methods: Thirty-two healthy volunteers performed dental scaling to remove artificial calculus on dental manikin. The movement and angle of the joints were verified by RULA and 3D motion analysis during the procedure. The subjects were also photographed for 1 minute during the procedure for 10 minutes while the calculus was removed. After the removal of the calculus, the subject and the instructor checked the video together. Posture correction training was conducted by the instructor so that the subject could perform the calculus removal operation in the correct posture. Artificial calculus of the adjacent teeth was then removed for the same period of time, and the change in posture was reviewed. Results: The total score of the posture change using RULA was $5.72{\pm}0.58$ before training and $4.31{\pm}0.10$ after training, showing a significant decrease after training (p<0.001), and upper arm, lower arm, wrist position, neck and waist position showed significant decrease after training. The three-dimensional motion analysis showed significant differences according to the criteria measured at all measurement sites except the left shoulder (p<0.05) Conclusions: It was confirmed through RULA and 3D motion analysis that postural correction training using calculus removal images was effective, and that correct postural education is essential to preventing musculoskeletal diseases caused by removal of calculus.