• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.382-385
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• 2003

Chemical mechanical polishing(CMP) is an essential process in the production of copper-based chips. On this work, the stability of Hydrogen Peroxide($H_2O_2$) as oxidizer of Cu CMP slurry has been investigated. $H_2O_2$ is known as the most common oxidizer in Cu CMP slurry. Copper slowly dissolves in $H_2O_2$ solutions and the interaction of $H_2O_2$ with copper surface had been studied in the literature. Because hydrogen peroxide is a weak acid in aqueous solutions, a passivation-type slurry chemistry could be achieved only with pH buffered solution.[1] Moreover, $H_2O_2$ is so unstable that its stabilization is needed using as oxidizer. As adding KOH as pH buffering agent, stability of $H_2O_2$ decreased. However, stability went up with putting in small amount of BTA as film forming agent. There was no difference of $H_2O_2$ stability between KOH and TMAH at same pH. On the other hand, $H_2O_2$ dispersion of TMAH is lower than that of KOH. Furthermore, adding $H_2O_2$ in slurry in advance of bead milling lead to better stability than adding after bead milling. Generally, various solutions of phosphoric acids result in a higher stability. Using Alumina C as abrasive was good at stabilizing for $H_2O_2$; moreover, better stability was gotten by adding $H_3PO_4$.

• The Transactions of the Korean Institute of Electrical Engineers C
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• 제50권1호
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• pp.6-10
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• 2001

In this study, we investigated the optical properties of sub-wavelength a-Si thin film transmission gratings, especially the polarization effect, the phase difference and the birefringence by using linearly polarized He-Ne laser beam (632.8nm). The a-Si transmission grating of the thickness $of < 0.1 \mum$ with four-type period($\Lambda = 0.4 \mum and 0.6 \mum$ for sub-wavelength and $\Lambda = 1.0 \mum and 1.4 \mum$ for above-wavelength) on quartz substrates have been fabricated using 50 KeV Ga+ Focused-Ion-Beam(FIB) Milling and $CF_4$Reactive-Ion-Etching(RIE) method. Finally, we obtained the trating array of a-Si thin film with a period $0.4 \mum, 0.6 \mum, 1.0 \mum, 1.4 \mum$ which have nearly equal finger spacing and width, sucessfully. Especially, for gratings with $\Lambda = 0.6 \mum(linewidth=0.25 \mum, linespace=0.35\mum), the \etamax at \theta_в=17.0^{\circ}$ is estimated to be 96%. As the results, we believe that the sub-wavelength grating arrayed a-Si thin film has the applicability as the optical device and components.

• Journal of Technologic Dentistry
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• 제40권1호
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• pp.1-8
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• 2018

Purpose: The purpose of this study is to evaluate the trueness and fitness of machined prostheses according to drill radius setting in CAD software. Methods: For this study, standard abutment were replicated in Type IV stone. The stone abutment were scanned using a dental scanner. The CAD design software was designed using scanned abutment data. When designing, the drill radius was set to 0.3 mm and 0 mm, respectively, and saved. The saved design data was milled using a milling machine (n=13). The inner surface of the milled crown was scanned. The trueness and fitness were measured using the inner scan data of prostheses. Independent t-tests were performed to identify significant differences in each data. Results: Trueness values of the data saved with 0.3 mm and 0 mm drill radius were $18.9{\pm}2.3{\mu}m$ and $19.1{\pm}0.9{\mu}m$, respectively. There was no statistically significant difference between the groups. Fitness values of the data saved with 0.3 mm and 0 mm drill radius were $65.5{\pm}0.8{\mu}m$ and $33.8{\pm}1.0{\mu}m$, respectively. There was a statistically significant difference between the groups (p<.05). Conclusion : Setting the drill radius is important to produce clinically good fit prostheses.

• Applied Biological Chemistry
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• 제21권3호
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• pp.193-196
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• 1978

Wheat quality score index was proposed as a new criterion of wheat_quality for evaluation of the laboratory testing value such as milling rate (Xm), flour ash content (Xa), flour protein content (Xp) and sedimentation value (Xs). 1) Wheat quality score index was expressed as follows; Milling score index (MSI) $=2.3X_m-72.4X_a$ Protein score index (PSI) =$5.2X_p+0.9X_{psi}$ Composite quality score index (QSI) =$0.63X_{msi}+0.37X_{psi}$ 2) The samples with the more than 100 of MSI would be the good milliability, and the samples with more than 100 of PSI would be the good bread making properties, while that with less than 100 of PSI be good pastry type properties. Whereas most of the samples with higher value of QSI would be related to the good milliability and good bread making properties. 3) MSI, PSI and QSI were significantly correlated to the each related quality components.

• Journal of the Korean Society of Manufacturing Process Engineers
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• 제18권9호
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• pp.72-80
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• 2019

In this task, the tool dynamometer design and manufacture, and the Ansys S/W structural analysis program for tool attachment that satisfies the cutting force measurement requirements of the tool dynamometer system are used to determine the cutting force generated by metal cutting using 3-axis static structural analysis and the LabVIEW system. The cutting power in a cutting process using a milling tool for processing metals provides useful information for understanding the processing, optimization, tool status monitoring, and tool design. Thus, various methods of measuring cutting power have been proposed. The device consists of a strain-gauge-based sensor fitted to a new design force sensing element, which is then placed in a force reduction. The force-sensing element is designed as a symmetrical cross beam with four arms of a rectangular parallel line. Furthermore, data duplication is eliminated by the appropriate setting the strain gauge attachment position and the construction of a suitable Wheatstone full-bridge circuit. This device is intended for use with rotating spindles such as milling tools. Verification and machining tests were performed to determine the static and dynamic characteristics of the tool dynamometer. The verification tests were performed by analyzing the difference between strain data measured by weight and that derived by theoretical calculations. Processing test was performed by attaching a tool dynamometer to the MCT to analyze data generated by the measuring equipment during machining. To maintain high productivity and precision, the system monitors and suppresses process disturbances such as chatter vibration, imbalances, overload, collision, forced vibration due to tool failure, and excessive tool wear; additionally, a tool dynamometer with a high signal-to-noise ratio is provided.

• Physical Therapy Rehabilitation Science
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• 제6권2호
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• pp.71-76
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• 2017

Objective: The purpose of this study was to investigate the musculoskeletal diseases (MSDs) that occur in heavy industrial workers according to the occupational category, prevalence, environment, and number of physical therapy visits. Design: Retrospective cohort study. Methods: For this study, data was collected of workers who were engaged in heavy industry in Korea and who visited the company physicians and received physical therapy in 2016. Data was collected from 855 subjects and was analyzed. With the data collected, analysis of the type and prevalence of MSDs and the number of physical therapy visits that have occurred according to the occupational category and environment was performed. Results: The most common MSDs were lumbar sprains and spasms (31.1%), and shoulder sprain and spasm (19.4%). In addition, the most common type of MSDs according to the occupational category and environment (occupational type) were lumbar sprain and spasms in 11 occupations, including white collar workers, and in milling, inspection, crane operation, and finishing jobs, shoulder muscle sprain and strain were the most common disorders. Also, the prevalence of MSDs according to occupational category and environment (occupational type) was the highest in workers involved with welding, which was 29.7%. Conclusions: Through this study, the type and prevalence of MSDs according to the occupational category and environment of heavy industrial workers have been confirmed. Further studies are necessary to study the future types of the work patterns of industrial workers and to develop a system for preventing and managing MSDs that may occur.

• Proceedings of the Korean Society of Crop Science Conference
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.262-262
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• 2017

Brown rice contains a variety of nutritional and bio-functional components compared to milled rice. However, low consumer preference for steamed brown rice and short shelf life has been implicated as deterrents to the direct consumption of brown rice. This study was undertaken to determine the effect of degree of milling (DOM) on pasting and aging properties of brown rice cultivar. Short-grain (Japonica type) brown rice cv. Boseogchal (BSC), Baegjinju (BJJ), and Hiami (HIAM) were evaluated every month during 4 months storage. Rice cultivar were categorized into waxy (BSC), medium-waxy (BJJ), and non-waxy (HIAM) of which amylose contents were 6.81%, 10.06%, and 16.69~16.72%, respectively. Peak viscosity was the highest in BJJ followed by HIAM, and BSC, showing peak viscosity was lower at low temperature storage. At storage at room temperature from 60 to 120 days, the FFA content significantly increased in the rice samples with DOM1% followed by 3% and 5%, while not significant increase in DOM0% brown rice: at 120 days, the FFA ranged in 28.35~41.48, 111.99~130.06, 76.87~91.99, and 47.13~62.37 mg KOH/100g for DOM 0%, 1%, 3% and 5%, respectively. It indicated that the fat rancidity was the least in the order of DOM 0%, 5%, 3% and 1%. Storage at low temperature could reduce fat hydrolysis with lower FFA release, but rice grain with 1% MD also released more FFA compared to the other samples. It could be assumed that the most outer bran layer, approximately 1~3%, could provide a strong protection from fat rancidity. Pasting viscosity of rice samples also increased with increasing DOM rate. Results indicated that DOM was the most significant factor for lipid rancidity during storage, resulting in high FFA formation. It suggested that brown rice with DOM 0% and/or more than DOM 5% could provide the best shelf life.

• Journal of the Korean Society of Food Science and Nutrition
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• 제19권6호
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• pp.617-624
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• 1990

Proper processing condition of Yukwa(oil popped rice snack) for mass production and pop-ping mechanism of it were tested with Shinsun (waxy, Japonica type rice) which was excellent for Yukwa making. Optimum steaming time of dough was 15 min among 4 to 60 min and reasonable moisture content of the dough before steaming was 4895 among 48 to 53% which had good and fine texture. Acceptable stirring time of steamed dough was not significantly different among 1 to 4 min, but no stirring with much larger volume was shown very poor and too soft in texture. At the simplification test of milling method, wet milling was better then dry milling in expansion rate and high temperature treatment of dough at 6$0^{\circ}C$ gave negative effect on their quality. Extending high temperature treatment of dough, reducing sugars in the dough increased and it might be caused of starch degradation. In addition of some other protein sources to dough, Yukwa quality were in proportion to the protein content of the beans. At the long term storage of the Yukwa base, moisture absorption was different depending upon RH of atmosphere and the quality of Yukwa was inferior by storage time. By addition of some alcoholic beverage, such as Makkoli, Soju and Chungju, expansion rate and their texture were somewhat improved by increasing addition amount of them from 15% to. 30％ on dough (w/w).

• Journal of the Korean Society for Precision Engineering
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• 제29권8호
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• pp.845-852
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• 2012

The diaphragm-type stylus probe was developed for ultra-precision on-machine measurement (OMM) application. This probe is equipped with two diaphragms which are parallel and one capacitive sensor is used for detecting the vertical motion of end tip in the stylus when it is contacted to the optical freeform surface. For better performance of proposed probes, several design parameters such as axial stiffness and the lateral deformations were investigated with finite element analysis techniques. To verify the feasibility, the profiles of the master sphere ball were measured on the ultra-precision milling machine. The measurement results show that the proposed probe can calculate the radius of the circle within the accuracy of 0.1 ${\mu}m$ for the ultraprecision optical surface.

• Progress in Superconductivity and Cryogenics
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• 제5권2호
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• pp.41-45
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• 2003

Resistance distribution in thin film type SFCL elements of different shunt layer thickness was investigated. The 300 nm thick film of 2 inch diameter was coated with a gold layer and patterned into 2 mm wide meander lines. The shunt layer thickness was varied by ion milling the shunt layer with Ar ions, and also by having the shunt layer grown in different thickness. The SFCL element was subjected to simulated AC fault current for measurements. It was immersed in liquid nitrogenduring the experiment. The resistance distribution was not affected by the shunt layer thickness at applied voltages that brought the temperature of the elements to similar values. This result could be explained with the concept of heat transfer from the film to the surroundings. The resistance distribution was independent of the shunt layer thickness because thick sapphire substrates of high thermal conductivity dominated the thermal conductance of the elements.