• The Journal of the Acoustical Society of Korea
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• v.23 no.5
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• pp.353-361
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• 2004

Propagation of the guided waves in a steam generator (SG) tube was investigated. Dispersion curves and the incident angles corresponding to the specific modes were calculated for the SG tube. The modes of guided wave were identified by time-frequency diagrams obtained by short time Fourier transform. Group velocities were also determined from the time-frequency diagrams obtained at the different separations of transducers. In experiment. distinct mode conversion was not observed when the guided ultrasound passed curved region of the S/G tube. The optimum mode of guided wave for the inspection of SG tube was suggested and verified by experiments.

• Women's Health Nursing
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• v.17 no.2
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• pp.178-186
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• 2011

Purpose: The purpose of this study was to identify effects of guided imagery on stress including cognitive, affective, marital and social, and anxiety among women receiving in vitro fertilization (IVF). Methods: Data were collected between April, 21 and June, 17, 2008. The participants in this study were 57 women (26 for the experimental group, 31 for the control group) receiving IVF for primary or secondary infertility in one of the outpatient infertility centers in Seoul. The guided imagery (Suk, 2001) was provided through audio CD to the experimental group by themselves 8 minutes per day for 2 weeks. Data were analyzed by SPSS 12.0 windows program. Results: After guided imagery, the experimental group showed significantly lower affective stress and total stress scores. Anxiety scores increased significantly in the control group, but not in the experimental group after treatment. Conclusion: The findings suggest that guided imagery is an effective nursing intervention for reducing stress especially affective stress and anxiety among infertile women receiving IVF in outpatient infertility center.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.10
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• pp.1257-1264
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• 2011

Guided ultrasonic waves propagating over long distances within a short period provide a fast long-range inspection method. However, structures with arbitrary cross-sections, such as rails, have complicated dispersion characteristics that make analysis of the ultrasonic signal difficult. Therefore, an understanding of the characteristics of the propagating waves in rails is important for the creation of a reliable and practical inspection system using guided waves. In particular, it is necessary to investigate the dispersion characteristics of the guided waves. This paper introduces a method for the calculation of the dispersion curves of KS60 rails by adopting a SAFE method, and discusses the possibility of using guided waves as a technique for rail inspection.

• Convergence Security Journal
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• v.7 no.2
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• pp.145-154
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• 2007

In this paper, a study on the actuator device technology in guided weapon system development. Hydraulic and pressure, electric motor device had been mostly used, but recently due to high output to weight ratio, pressure actuator device is widely used except for small tactical guided ammunition which needed small power. And now the actuator design concept and technical level is changed because of high mobility of guided ammunition, development of magnetic materials which used new material for requirement of despondence, progress of control and electrodynamics technology, and digitalize and integrity. In this paper we clearly proposed the actuator design criteria and detailed technology development trend for next generation guided weapon system.

• Smart Structures and Systems
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• v.9 no.5
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• pp.461-472
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• 2012

This study proposes an optics-based active sensing system for continuous monitoring of underground pipelines in nuclear power plants (NPPs). The proposed system generates and measures guided waves using a single laser source and optical cables. First, a tunable laser is used as a common power source for guided wave generation and sensing. This source laser beam is transmitted through an optical fiber, and the fiber is split into two. One of them is used to actuate macro fiber composite (MFC) transducers for guided wave generation, and the other optical fiber is used with fiber Bragg grating (FBG) sensors to measure guided wave responses. The MFC transducers placed along a circumferential direction of a pipe at one end generate longitudinal and flexural modes, and the corresponding responses are measured using FBG sensors instrumented in the same configuration at the other end. The generated guided waves interact with a defect, and this interaction causes changes in response signals. Then, a damage-sensitive feature is extracted from the response signals using the axi-symmetry nature of the measured pitch-catch signals. The feasibility of the proposed system has been examined through a laboratory experiment.

• Journal of Power System Engineering
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• v.14 no.5
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• pp.36-40
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• 2010

The ultrasonic guided wave propagates along with the given structure's wall direction. Because of this specific character, the ultrasonic guided waves arc used in many other fields. Especially, it can be readily utilized for nondestructive inspection of various structures that are made up of gas pipes, heat exchanger tubes, and thin plates. Further, the guided wave technology can be readily utilized when inspecting pipes or thin plates which pose high risk of the accident but for which the nondestructive inspection itself is impossible because it is difficult to get to them since they are coated or buried underground. In the other hand, conventional ultrasonic testing such as thickness gauging uses bulk waves and only tests the region of structure immediately below the transducer. As a result of the application about inlet and outlet cooling water line using guided wave test, we conformed that the overall corrosions were in the lower side of the 304.8 mm inlet valve and these corrosions were engaged in not locally but through the lower side of the valve line. In the near future, we can expect that the detectable defect size is smaller than before along with the development of the sensing technology.

• Journal of Acupuncture Research
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• v.41 no.2
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• pp.135-141
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• 2024

The use of ultrasound (US)-guided interventions has rapidly increased in Korean medicine (KM) to ensure the safety and accuracy of invasive procedures, such as pharmacopuncture and acupotomy. Although hands-on training is important for the acquisition of skills, it requires considerable time and cost. A detailed guide on the procedure and treatment regions is needed to ensure hygiene and safety during US-guided procedures in KM practice. In this study, we present the overall procedure, target structures, and treatment approaches of US-guided pharmacopuncture and acupotomy for nerve entrapment in the upper extremities of the cubital and radial tunnel, posterior interosseous nerve, carpal tunnel, and Guyon's canal syndrome. We believe that the findings of our study will serve as a foundation for future clinical research, practice, and education on US-guided KM procedures. Further research involving US-guided interventions should specify target structures in three-dimension to delineate the treatment areas.

• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.3
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• pp.206-212
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• 2000

The guided wave mode conversion phenomena were investigated for the NDE of a plate-like structure with thickness variation. The ratios of reflection and transmission (R/T) were measured via the self-calibrating procedure which allows us to obtain experimental guided wave data in a more reliable way regardless of the coupling uncertainty between transducer & specimen. The results on R/T could be used to determine the thickness reduction of the structure. It was shown that not only the incident modes but also the converted ones need to be considered in the self-calibrating guided wave inspection to extract a reasonable correlation between experimental data & the thickness variation. Through this study, the potential of guided wave inspection as a quantitative NDE technique was explored based on the combined concept of self-calibration & multi-mode conversion in guided wave scattering problems.

• Journal of Acupuncture Research
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• v.28 no.2
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• pp.165-172
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• 2011

Objectives : The objective of this case report was to observe the effect of musculoskeletal ultrasound-guided acupotomy therapy on posterior headache caused by traffic accident. Methods : Musculoskeletal ultrasound-guided acupotomy therapy was performed to two patients whose brain MRI or CT results were normal, but posterior headache did not improve with general eastern medical treatment. Results : One patient's VAS(visual analogue scale) of posterior headache was decreased for the first time after ultrasound-guided acupotomy therapy, and steadily reduced. The other patient's VAS was also decreased for the first time after musculoskeletal ultrasound-guided acupotomy therapy. Two patient's Korean HIT-6(Korean headache impact test-6) scores were decreased after one month. Conclusions : If general eastern medical treatment had little effect on traffic accident induced posterior headache, musculoskeletal ultrasound-guided acupotomy therapy can be applied.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.4
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• pp.367-373
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• 2011

Guided waves inspection techniques that are different with inspection technique by bulk waves are widely used in pipe line evaluation due to advantages of long distance inspection. However, most of pipe lines at industrial fields are buried and/or coated. In this case, due to the attenuation effect from soil and/or coating material, there are a lot of difficulty on inspection by conventional ultrasonic technique. In this paper, guided waves propagating patterns are calculated with respect to excitation mode by Normal Mode Expansion(NME). Guided waves patterns based on excited by single transducer and guided wave focusing technique have employed to analyze focusing pattern on a pipe. A longitudinal mode and high order flexural modes are used with various number of transducers to determine sensitivity. Guided waves energy excited by multi transducer with focusing algorithm was successfully focused at a desired point.