• The Journal of Korean Academy of Prosthodontics
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• v.38 no.6
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• pp.757-764
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• 2000

Statement of the problem. All-ceramic post-and-core restorations offer a number of advantages compared with systems that use metal build-ups. In certain clinical cases, however, fractures at the joint between the post and core build-up have been reported. Purpose. The objective, therefore, is to improve the joint between the post and the core build-up. Material and methods. Three different methods were used to prepare all-ceramic post-and-core restorations; pressing IPS Empress core build-ups to CosmoPost zirconia posts, cement-ing IPS Empress core build-ups to CosmoPost zirconia posts and Celay-milling of zirconia blanks. A series of ten restorations was prepared for each of the three methods. The post-and-core complexes were tested to failure with the load applied perpendicular to the post axis. The load and deflection at fracture were recorded. Results. The highest breaking load and highest deflection were recorded for the cementing technique with values of 25.3 N and $394{\mu}m$, respectively, The corresponding values for the pressed core build-ups and the milled zirconia core build-ups were 22 N and $301{\mu}m$, and 13 N and $160{\mu}m$, respectively. All the differences are statistically significant (p=0.05). Regarding the load-dependence of the deflection, the cemented core build-ups again demonstrated the highest value with $15.5{\mu}m/N$. The difference in the values of $13.6{\mu}m/N\;and\;13{\mu}m/N$ recorded for the pressed-on and milled core build-ups, respectively, were statistically insignificant. Conclusion. In regard to the high fracture resistance of zirconia post, adhesive cementing the core build-up to the post offers a viable alternative to the conventional pressing technique. The elastic bond between the rigid high-strength zirconia post and the core build-up presents an additional advantage.

• Journal of The Korean Society of Integrative Medicine
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• v.4 no.2
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• pp.77-88
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• 2016

Purpose : The purpose of this study was to explore an effect exerted to non-affected hand and affected hand of patients by performing training of chopsticks and grasp strength that are helpful to dexterity and grasp strength of hand together with training method of joint exercise, muscle strength build-up training, delicate hand function training. Method : By targeting 30 normal adult male/females engaged in K university, Busan for one month on April, 2015, 10 persons of hand function build-up training group, that of dexterity training group and 10 persons of control group were randomly selected. For hand function build-up training group, chopsticks training in parallel with total 20 times of grasp strength training for 4 weeks including 5 minutes of dominant hand grasp strength training, 5 minutes of non-dominant hand grasp strength training, 15 minutes of chopsticks training was performed based on 25 minutes/one time, 5 times a week. Result : First, In a comparison of dexterity of both hands by each group depending on training period, hand function build-up group and dexterity training group were represented to be effective compared with control group. Secondly, In a comparison of manipulatory ability of both hands by each group depending on training period, hand function build-up group and dexterity training group were represented to be effective compared with control group. Conclusion : It is considered that diversified and broad research covering patients with musculoskeletal disease and nervous system-related disease would be performed by securing far more test subjects after comparing a correlation between dexterity training and hand function training.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.2
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• pp.154-161
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• 1998

Prototypes of a design are always needed for the purpose of visualization and evaluation in the aspect of manufacturability functionality, and aesthetic appearance. Since the prototyping process requires a significant amount of cost and time, various rapid prototyping processes are recently being introduced in the process. However, it is usually necessary for a part built up by a rapid prototyping system to be refined by a post-processing process, in which the stair steps on the surfaces, the support structures (if they exist), and the unprocessed material are eliminated. This post-processing is usually done manually and is a time-consuming task. Especially, eliminating the trapped volumes, the volume of the unprocessed material entrapped by the solidified portion, is sometimes impossible in some processes. This study provides a designer with a tool to detect the existence and to calculate the quantity of the trapped volumes at the given build-up direction, so that the proper build-up direction is chosen or the part is built by pieces to avoid the problems caused by the trapped volumes in advance. Since the proposed algorithm can efficiently calculate the amount of the trapped volumes at any build-up direction, it has the potential of such application as optimizing the build-up direction to minimize the trapped volumes.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.6
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• pp.431-440
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• 1989

This paper proposes a new PWM cycloconverter which can step up input voltage. With input reactors ac power supply acts as current source, and with output capacitors the balanced output voltage is build-up. The converter is modeled with fourth order state equation using dq transformation and the steady state characteristics are evaluated. It is shown that the proposed converter can generate the output voltage 2-5 times greater than input voltage. The output voltage and input current have sinusoidal and smooth waveforms and the converter is capable of voltage build-up. The characteristics of the proposed converter is verified simulation and experiment.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.242-242
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• 2003

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.167-168
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• 2011

• Journal of environmental and Sanitary engineering
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• v.13 no.2
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• pp.128-138
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• 1998

This study was focused to find how each factors effect on the biological nitrification in wastewater treatment under high ammonia nitrogen concentration. Batch reactors in aerobic conditions were used to test the treatment efficiency of mixed liquor, nightsoil and piggery wastewater. The results are summeried as follows; Initial ammonia nitrogen concentration and pH were the direct influencing factors of nitrite build-up. More than 250 mg NH$_{4}$$^{+}$ - N/L in initial concentration built up nitrite and then the inhibition rate to Nitrobacter was above 70 percentage. And maximum nitritation rate was showed at pH 8.3 and nitrification could be completely achieved by pH control. Temperature and dissolved oxygen were the indirect influencing factors of nitrite build-up. These were a great effect on the activity of nitrifying microbes and ammonia nitrogen removal. Maximum nitritation rate was showed at 30 $\circ $C. The effect of DO concentration was negligible at more than 3 mg/L.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.12 s.255
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• pp.1139-1146
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• 2006

Light Oil Flow Standard System(LOFSS) in Korea Research Institute of Standards and Science(KRISS) was designed for oil flowmeter calibration. In order to extend the flow range from 120 $m^3/h$ to 200 $m^3/h$, the build-up technique was applied with two positive displacement flowmeters as master flowmeter. The master flowmeters were calibrated against with LOFSS, which has 0.04 % uncertainty of flow quantity determination, then the test flowmeter is calibrated against two master flowmeters. For uncertainty analysis, the repeatability of master flowmeters, the variation of the fluid density and the pipe volume due to temperature change were scrutinized. The contribution of each uncertainty factors to the calibrator and the correlation of each factors were discussed. For investigating the feasibility of uncertainty analysis, a turbine flowmeter as a transfer package was tested with LOFSS and two reference flowmeter. The hypothesis test for both results was coincide with a 95 % significant level. This means that the uncertainty analysis procedure of the calibrator is reasonable and the extension of flow range with master meters was carry out successfully.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.2 no.2
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• pp.19-32
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• 1979

The title of research is a study on the leadership in Korean management. The purpose of research is that I build up the ideal management-leadership in future which is objective and suitable studying through the existing theory at all points, and analyzing the leadership in Korean management concentrated on situational factors. Moreover it contributes to the promotion of productivity, the contents of research 1. The importance of management-leadership. 2. The development in theory concentrated on a principle of leadership. 3. The development in behavioral scientific leadership, which adopts situational approach to its methodology. 4. The study on the leadership-style and the pursuit of the ideal management-leadership in accordance with behavioral analysis. 5. The build up of leadership in Korean management. The refore I learn the following facts through the study on the leadership in modern management. 1. Leadership consists of the relations among all interdependant variables composing of system. 2. The problem of the increase in the management-leadership effectiveness. 3. The pursuit oriented ideal management-leadership. 4. The build-up of leadership in Korean management. So far 1 have studied the theory of management-leadership at all points and the leadership in Korean management concentrated on situational factors. I learn that leadership is made of the relations among these in building the future management-leadership. Therefore I try to come to the conclusion by raising the following three problems. 1. The increase in leadership effectiveness. 2. Leadership-oriented. 3. The build-up of the leadership in Korean management.

• Journal of Radiation Protection and Research
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• v.14 no.2
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• pp.37-44
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• 1989

An improved water chemistry technique was studied to reduce radioactivity build-up in reactor coolant system. The technique is convering the current coordinated lithium-boron chemistry regime to the elevated lithium chemistry regime in order to maintain high pH. Correlations between reactor coolant pH and radioactivity build-up were analized by using pH data from domestic PWRs. Consequently, it was founded that high pH chemistry was moer effective for radioactivity build-up reduction than current chemistry regime. This fact had revealed that much portion of reactor coolant corrosion products were nickel ferrite rather than magnetite, and that pH value ranging 7.0-7.4 was appropriate for high-pH chemistry operation.