• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.11
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• pp.1157-1162
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• 2011

The parking brake is an essential unit embedded in the track-driving motor of an excavator. The parking brake plays an important role in keeping the excavator in place not only when it is parked, but also during the digging operation. In fact, the load placed on the parking brake during the digging operation is significantly higher than the parking load, because the impact and rating loads caused by the bucket digging force cycle frequently and have very high load ranges. Therefore, the load conditions during the digging operation should be taken into account in the parking brake certification test. In this study, a series of experiments was carried out in which various operating pressures were applied to the parking brake, where repeated loads were reciprocally placed on the brake by locking the multifriction disc and releasing the hydraulic cylinder. The characteristics of the parking brake were investigated by comparing the obtained experimental results and the theoretical design specifications.

• Journal of East-West Nursing Research
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• v.20 no.1
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• pp.9-20
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• 2014

Purpose: The purpose of this research was to examine the effects of preferred music intervention on anxiety, vital signs and blood sugar of surgical patients undergoing spinal anesthesia. Methods: A quasi-experimental research with non-equivalent control group non-synchronized design was carried out. Subjects consisted of 40 patients (experimental group 20, control group 20) who were scheduled to undergo surgery with spinal anesthesia. During the operation, music individual patients preferred was provided to the experimental group. The data were collected from July 4 to November 10, 2011 and analyzed with descriptive statistics, t-test, chi-square test, ANCOVA and repeated measured ANCOVA using SAS (ver 9.2). Results: 1) Patient anxiety during the operation of the experimental group was significantly lower than the control group (F=93.77, p<.001). 2) There was no significant difference in diastolic blood pressure (F=.00, p=.979), Systolic blood pressure (F=.19, p=.668), heart rate (F=.00, p=.955), and blood sugar (F=.73, p=.399) between the experimental group and the control group. Conclusion: Letting patients hear their preferred music during surgery is an effective nursing intervention to relieve anxiety of patients undergoing surgery with spinal anesthesia.

• Journal of Korean Clinical Nursing Research
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• v.14 no.1
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• pp.187-198
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• 2008

Purpose: Music intervention has long been used in research of patients undergoing surgical operation in reducing anxiety level and improve surgical outcome. However, there are few studies that have considered a patient's music preference. We investigated the effect of the tailored music intervention which chose music according to the patient's preference on anxiety level and vital signs. Method: The subjects were 50 patients who received regional anesthesia for surgical operation at D hospital in Pohang city from April, 2006 to November, 2006. All of the subjects were randomly assigned either music group (30 subjects) or non-music group (20 subjects). As the patients arrived in the operating room, vital signs were monitored until the subjects were transferred to the recovery room, while Spielberger's STAI-KYZ questionnaires were applied twice to measure preoperative and intra-operative anxiety. The data were analyzed by 2-test, t-test, one-way ANCOVA and repeated measures ANOVA using SPSS 12.0/PC+. Results: There were no significant differences between the two groups on vital signs. All of the vital signs increased when the subjects arrived in the operating room, but decreased quickly once the operation began, regardless of the groups. However, the music group reported significantly less intra-operative anxiety, compared to the non-music group (F=15.208, p<.000), when preoperative anxiety was treated as a covariance. Conclusion: The findings support that the use of music which was chosen by patients during the surgery significantly reduced patient's intra-operative anxiety during regional anesthesia.

• Journal of Technologic Dentistry
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• v.16 no.1
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• pp.12-42
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• 1994

The study objected to the 36persons out of 55 persons who have registered under the association of the professor of department of Dental Laboratory Technology to grasp contents of May, 1992, and objected to the 74persons out of 100persons who have registered under the association of an a lumni of Department of dental Laboratory Technology, Jisan Junior college to grasp contents about improvement of dental laboratory technology, Jisan Junior College to grasp contents about improvement of the national practical examination in the dental technician of the present day of May, 1994 and its results which we have acquired by this study were as follows : There are lots of opinions who have required the necessities to enforce for a national practical examination in the dental technician. A sense of satisfaction forward the system of a national practical examination in the dental technician appeared as unsatisfaction and it's unsatisfaction decreased from evaluation me operation method, the makes of questions, selection of a markers, distribution of marks of a practical examination. The operation method of a practical examination have appeared the opinions which they wished the present system. A date of operation a practical examination have appeared the opinion of which they preferred late in February. The distribution of marks of a practical examination have appeared the opinions which they wished the present system. The problem of the makes of questions of carving test which derived by an out flow of cast appeared which 52.7 percent(58 persons), lack of objectivity and lack of a standard evaluation appeared which 40 percent(44 persons), and lastly appeared. 5.5 percent(6 persons) with partiality of a questions. The problem of the makes of question of Q-test which derived by lack of a standard evaluation appeared which 44.5 percent(49 persons), lack of objectivity appeared which 39.1 percent(43 persons).

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.6
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• pp.96-103
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• 1997

This paper deals with the malfunction characteristics of the earth leakage circuit breakers(ELBs) applied by a lightning impulse voltage. In the cases of the regulation of KS C 4613 and the simulated circuits with surge protection devices, the dead operation characteristics of the ELBs against lightning impulse voltages were experimentally investigated and discussed. As a result, all the specimens(ELBs) used in this work have a cutoff performance of the lightning impulse voltage when the differential mode surges were injected at the input terminals of the ELBs owing to a surge absorber installed at the power source side of amplification circuit. Four kinds of the specimens have brought about malfunction in the condition of the lightning impulse dead operation test defined in KS C 4613, and the malfunction voltages are relatively high and are about 5-6.5[kV]. In the case of the simulated test circuit with surge protection devicesthree kinds of the ELBs have led to malfunction. Also the voltage level causing the malfunction of the ELBs is decreased by operation of surge protection devices, and it ranges from 3 to 5(kV).

• Journal of the Society of Naval Architects of Korea
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• v.58 no.3
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• pp.198-205
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• 2021

In this paper, the effect of trim variation on the required power of 11,000TEU container ship was investigated under conditions considering the actual operation speed and draft. For each draft condition, the effective power (P_E) and delivered power (P_D) trends were investigated with changes in trim and ship speed. At this time, the displacement volume was fixed same as the value of the even trim condition and the both sinkage at the fore and after perpendicular are confirmed. The test ship speeds were determined by considering the operating speed. Both numerical and experimental methods were used to analyze the effects of trim variation. Numerical analysis results were used for evaluating the resistance performance, and the self-propulsion performance was estimated using experimental data obtained from model test.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.5
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• pp.87-92
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• 2019

This study is the analysis of causes of printed circuit board (PCB) in collective protection equipment failure and quality improvement. The equipment is a component of the weapon system currently in operation and serves to defend against enemy chemical and biological attack as well as heating and cooling functions. However, during operation in the military, fans of condensate assembly failed to operate. The cause of the failure is the burning of PCB. It was found that the parts were heated according to the continuous cooling operation under the high temperature environmental conditions. Accordingly, the electronic components exposed to high temperature were deteriorated and destroyed. To solve this problem, PCB apply to heatsink. The performance test of improved PCB has been completed. Futhermore system compatibility, positive pressure maintenance and noise test were performed. This improvement confirmed that no faults have occurred in PCB so far. Therefore, the quality of the equipment has improved.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.4
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• pp.294-303
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• 2005

This paper describes the analysis results of a series f Round-Robin test that was performed to intercompare inspection and diagnosis techniques for characterization of pressure tube f a pressurized heavy water reactor under the Coordinated Research Project(CRP) of IAEA's nuclear Power Programme. For this test, six nations, Korea, Canada, India, Argentina, Rumania, and China that currently have pressurized heavy water reactors under operation involved, and the "KOR-1" pressure tube sample prepared by Korea was used. Two kinds of NDE technique, ultrasonic and eddy current test, were applied for these tests. The "KOR-1" pressure tube sample contains total 12 artificial flaws such as crack-like EDM notches, wear that is similar to the real flaws and can be produced on the pressure tubes during plant operation. Test results showed that seven laboratories from six nations detected all twelve flaws in "KOR-1" specimen by using ultrasonic and eddy current test methods, and ultrasonic test method was more accurate than eddy current test method in flaw detectin and sizing. ID flaws in pressure tube sample were more easily detected and accurately sized than OD flaws.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.209-214
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• 2017

Most of the present potential transformers of train vehicles are of the oil-type filled with insulating oil and are susceptible to problems such as explosion due to the increase in the internal pressure during train operation and poor reliability near the end of their life cycle. As a solution to this problem, it is necessary to develop a molded dry-type potential transformer with excellent pressure-resistance performance using insulating resin. In order to localize the product, the Korea Railroad Research Institute has been developing a molded dry-type potential transformer. As part of this research, it is necessary to analyze the vibration characteristics of the developed product and to check the transformer performance in a vibration environment. In this study, a resonance test and simulated long-term life test of the developed product were conducted according to the KS R 9144 and IEC 61373 standards, respectively, which are vibration test methods for railway vehicle parts. Their natural frequencies were analyzed by comparing the results of the numerical modal analysis and resonance test, in order to confirm their adherence to the standards. Also, the performance test after the simulated long-term life test confirmed that the operation of the developed transformer was not problematic even in a long-time vibration environment.

• Journal of Korean Orthopaedic Sports Medicine
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• v.1 no.1
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• pp.26-30
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• 2002

Purpose: To estimate the initial and early phase fixation power of the human bone interference screw in reconstruction of the anterior cruciate ligament with bone-patellar tendon-bone allograft. Materials and Methods: The results of twenty eight knees of reconstruction with bone-patellar tendon-bone allograft were analysed in 6 weeks, 12 weeks, 6 months and one year following operation. Physical examination including Lachman test, flexion rotation drawer test and jerk test were performed. The KT-1000 measurement was performed at the same time. In Lachman test 0 $\~$2mm anterior displacement of the tibia was considered normal. The KT-1000 measurement of normal side was compared with operation side and the difference of the two was recorded. The MRI was checked at final follow-up. Results: All but one knee showed normal in physical examination. The failed case showed proximal migration of the graft due to insufficient number of interference screw fixation in widened tibial tunnel. Conclusions: The human cortical bone interference screw showed sufficient initial and early phase fixation power in reconstruction of the anterior cruciate ligament.