• International Journal of Automotive Technology
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• v.4 no.4
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• pp.157-164
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• 2003

An experimental and numerical study was performed to investigate the macroscopic and microscopic atomization characteristics of high-speed diesel spray issued from the common-rail injection system. For the experiments, spray visualization system and a phase Doppler particle analyzer system were utilized to obtain the spray atomization characteristics such as the process of spray development, spray tip penetration, and SMD distribution. In order to analyze the process of spray atomization with KIVA-3 code, the TAB breakup model is changed to the KH-DDB competition model, which assumes the competition between the wave instability and droplet deformation causes the droplet breakup above the breakup length. The calculated results were also compared with the experiments in terms of spray tip penetration and SMD distribution. The results provide the process of spray development, axial and radial distribution of SMD, and calculated overall SMD as a function of time after start of injection.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.6
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• pp.23-29
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• 2004

This work was conducted to figure out the atomization characteristics of three types of bio-diesel fuels using a common-rail injection system. The process of spray development was visualized by using a spray visualization system composed of a Nd:YAG laser and an ICCD camera, The spray tip penetrations were analyzed based on the frozen images from the spray visualization system. On the other hand, the microscopic atomization characteristics such as the distributions of SMD and axial mean velocity were measured by using a phase Doppler particle analyzer system, It is revealed that the sprays of the bio-diesel fuels have larger SMD than that of diesel fuel mainly due to high viscosity of bio-diesel. Different characteristics of bio-diesel fuels were also measured in spray tip penetrations according to the fuels and mixing ration.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.6
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• pp.2515-2518
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• 2012

Aim: To study the causes and significance of both microscopic and macroscopic haematuria in adult patients and assess possible relevance to early detection of urological cancers. Methods: 417 patients presenting with haematuria were assessed in our Urology Unit. Following confirmation of haematuria, these patients were subjected to imaging techniques and flexible cystoscopy. Parameters analysed included clinical characteristics, imaging results, flexible cystoscopy findings, time delay to diagnoses and eventual treatment and final diagnoses of all cases. Results: 390 haematuria cases were analysed from 417 consecutive patients with haematuria. After 27 cases were excluded as they had previous history, 245 microscopic and 145 macroscopic. Age range was 17 to 95 years old with predominance of 152 females to 239 males. The racial distribution included 180 Chinese, 100 Indians,95 Malays and 15 other races. The final diagnoses were benign prostatic hyperplasia (22.6%), no cause found (22.3%), other causes (18.7%), urolithiasis (11.5%), urinary tract infection UTI (10.8%), non specific cystitis (10.3%), bladder tumours (2.8%) and other genitourinary tumours (1%). 11 new cases (2.8%) of bladder cancers were diagnosed, with a mean age of 59 years. Only 3 of 245 (1.2%) patients with microscopic haematuria had newly diagnosed bladder tumour compared with 8 of 145 (5.5%) patients with frank haematuria (p=0.016). Mean time taken from onset of symptoms to diagnosis of bladder cancer was 53.3 days with definitive treatment (TURBT) in 20.1 days from diagnosis. Conclusion:- This study has highlighted the common causes of haematuria in our local setting. We recommend that full and appropriate investigations be carried out on patients with frank haematuria especially those above 50 years old in order to provide earlier detection and prompt management of bladder diseases especially tumours.

• Journal of Engineering Education Research
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• v.19 no.5
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• pp.13-24
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• 2016

The purpose of this research is to examine the characteristics of team interaction according to the creativity of team members. Research subjects to achieve this purpose included 28 students who are in engineering education in the College of Education at A University in Daejeon and have taken robot-related courses. Through first and second MBTI, and TTCT tests, the final homogeneous and heterogeneous teams were formed, and an experimental study was conducted by developing team design activity assignment. The major research results were as follows. In terms of a comprehensive view on interaction frequency, both homogeneous team and heterogeneous team suggested had the highest frequency in suggesting opinions. However, each of the team members in the homogeneous team had different communication frequency among each other while each team member in the heterogeneous team had almost similar frequency. A microscopic analysis of the communication process of homogeneous team showed that the team members' roles were divided among each other in communication. Next, according to the microscopic analysis of the heterogeneous team's communication process, the team members exchanged opinions in the beginning, talked to themselves in words that were hard to understand the meanings, and they stopped having conversations in the end. Due to such decrease in communication, two team members could not solve the confusing state of being unable to understand each other's opinions and failed to complete their assignments. The microscopic analysis demonstrated that the homogeneous team had a smooth interaction, because when one team member suggested an opinion during a conversation, other team members agreed with it through a discussion. However, the members in the heterogeneous team experienced confusion as they could not understand each other's conversation and could not overcome this problem, leading to lack of conversations.

• Journal of the Korean Wood Science and Technology
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• v.25 no.3
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• pp.83-95
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• 1997

The degradation mode of lignocellulose by anaerobic ruminal cellulolytic bacterium Ruminococcus albus F-40 was investigated. Birchwood holocellulose and filter paper were incubated as the sole carbohydrate sources with using the Hungate techniques. After 2 or 4 days of incubation, samples were employed for chemical and electron microscopic evaluations. The degradation rate of cellulosic substrates and the adhesion rate of bacteria to the substrates increased proportionally with the decrease of relative crystallinity of cellulose, indicating the preferential breakdown of amorphous cellulose, by this bacterium. X-ray diffraction analyses and polarized light microscopy showed, however, that crystalline cellulose was also degraded by R. albus. FT-IR spectra indicated that not only cellulose but hemicellulose was also degraded by this bacterium. Electron microscopic investigations showed the protuberant structures on the surface of R. albus. These structures were much more significant when bacterial cells were grown in the media containing insoluble substrates, such as cellulose, indicating clearly that bacterial protuberant structures were induced by the substrates. Protuberant structures extended from the bacterial cells adhered tightly to the substrates and numerous vesicles covered the surface of cellulosic substrates affected. Cellulosome-like structures were distributed on the cellulose matrix. Electron microscopic works showed that diverse surface organells of R. albus were involved in the degradation of cellulosic materials. SEM examinations showed the breakdown of cellulose by R. albus was proceeded by severeal routes : short fiber formation, defibrillation and destrafication of cellulose microfibril.

• Geomechanics and Engineering
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• v.34 no.5
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• pp.577-595
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• 2023

A dynamic triaxial discrete element numerical model of lightweight soil was established using the discrete element method to study the microscopic mechanism of expanded polystyrene (EPS) particles in the soil under cyclic loading. The microscopic parameters of the discrete element model of the lightweight soil were calibrated depending on the dynamic triaxial test hysteresis curves. Based on the calibration results, the effects of the EPS particles volume ratio and amplitude on the contact force, displacement field, and velocity field of the lightweight soil under different accumulated strains were studied. The results showed that the hysteresis curves of lightweight soil exhibit nonlinearity, hysteresis, and strain accumulation. The strain accumulated in remolded soil is mainly tensile strain, and that in lightweight soil is mainly compressive strain. As the volume ratio of EPS particles increased, the contact force first increased and then decreased, and the displacement and velocity of the particles increased accordingly. With an increase in amplitude, the dynamic stress of the particle system increased, and the accumulation rate of the dynamic strain of the samples also increased. At 5% compressive strain, the contact force of the particles changed significantly and the number of particles deflected in the direction of velocity also increased considerably. These results indicated that the cemented structure of the lightweight soil began to fail at a compressive strain of 5%. Thus, a compressive strain of 5% is more reasonable than the dynamic strength failure standard of lightweight soil.

• Korean Journal of Optics and Photonics
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• v.34 no.6
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• pp.261-268
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• 2023

We propose a compact differential interference contrast microscopic module, which enables snapshot measurements for quantitative phase imaging. The proposed module adopts the lateral shearing interferometric principle, which can obtain self-interference without a reference. Due to the absence of the reference, the system is more stable than the typical interferometric systems. It uses a polarization grating to generate two laterally shifted wavefronts based on its birefringence and polarizing beam-splitting characteristics. Furthermore, the use of a polarization camera does not require sequential measurements for the phase extraction. In the experiments, we observe and measure the timely varying changes of various specimens to verify the system performance with the bright field images and phase contrast images. Because the proposed microscopic module also has the merit of being adaptable to typical microscopy instead of using an imaging camera, it can conveniently replace conventional contrast microscopy.

• Journal of Korean Society of Transportation
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• v.25 no.2 s.95
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• pp.73-81
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• 2007

The purpose of this paper is to perform a basic study on the interaction between lanes, which can be achieved through analyzing traffic breakdown at the microscopic level. Using aerial photographic data for the microscopic analysis, this study analyzed the characteristics of traffic flow at a merging area. This research produced aggregated traffic data such as flows, speeds, and densities in 30 second intervals by lane for the macroscopic analysis and individual headway data by lane for the microscopic analysis. The paper contains an analysis of lane characteristics through flows, speeds, densities, and headway variations and also investigates the influence of ramp flows on mainline flows with space-time diagrams. Firstly, the merging area in this study is divided into three sections: before-merging, during-merging, and after-merging. The transition process was analyzed at each lane. Secondly, the breakdown was observed in detail with data divided in 50-foot units. The breakdown was checked through the relationships between ramp and freeway mainline flows, various techniques were proposed to analyze the breakdown, and the formation of breakdown was introduced as three stages in this study. In the near future, the findings of this study could contribute to determining the dynamic capacity on freeways by easily understanding changeable traffic breakdown patterns over time and space.

• Mycobiology
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• v.32 no.1
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• pp.54-56
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• 2004

During the study of mushroom flora in Hongneung Arboretum, Ileodictyon gracile was confirmed as new to Korea and described based on morphological and microscopic characteristics in here. This species has subhypogeous, clathrate structure, and obovoid spores. The clathrate structures have $4{\sim}12$ polygonal meshes.

• Tribology and Lubricants
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• v.24 no.1
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• pp.44-48
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• 2008

The wear characteristics of the gold alloy dental prosthesis have been investigated. The wear tests were performed by using a pin-on-disk wear tester at room temperature. Vickers hardness and fracture toughness measurement of dental materials were preformed. Microscopic observations on worn surfaces of specimens were conducted by microscope. The friction coefficient of the gold alloy dental prosthesis was investigated according to weight and slinging velocity. The hardness of the gold alloy dental prosthesis were similar and a half of the enamel of natural teeth.