• Proceedings of the Optical Society of Korea Conference
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• 2005.02a
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• pp.264-265
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• 2005

In this paper the conceptual design and development of a compact vertical type soft x-ray microscope is described. This x-ray microscope operates in the water window wavelength region(2.3 ${\sim}$ 4.4nm), where natural contrast between carbon(protein) and oxygen(water) allows imaging of unstained biological material their natural, hydrated environment. Until now, operational x-ray microscopes are based on synchrotron radiation sources, which limit their accessibility. Many biologists would benefit from having the x-ray microscope as a tool among other tools in their own laboratory, For this purpose we introduced the compact vertical type soft X-ray microscope with 50 nm resolution for biomedical application. The compact vertical type soft x-ray microscope is based on a laser plasma x-ray source, doubled ellipsoidal condenser reflective optics, diffractive zone plate optics and MCP coupled with CCD to record an x-ray image.

• Speech Sciences
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• v.15 no.3
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• pp.145-156
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• 2008

The goal of this study was to investigate acoustic and physiologic characteristics of two phonation types of 'Khoomei' which is a traditional singing style of people who live around the Altai mountains or Mongolia region. It can be produced two pitches simultaneously - high melody pitch can be perceived along with a low drone pitch. Sygyt and kargyraa styles are the most popular and identifiable styles and they can be recognized as the different sounds depending on the method of voice production. Two trained Mongolians participated and have used at least 5 - 6 years. The characteristics of this voice production were measured by using flexible fiberscope, Stroboscopy, Lx Speech studio, Spead, and Doctor Speech. In Sygyt style, very high vocal fold closure (71.50%) with both true and false vocal folds contact and strong breathing support was observed. They also showed that tongue height and harmonics were increased (around 10dB) with resonance cavity movement. In contrast, it was found that Kargyraa sound had very low pitch with relaxed stomach, less laryngeal tension and lower vocal fold contact (69.50%) than hard Sygyt style sound without raising the tongue during phonation. 'Khoomei' phonation can be made by strong contact of both true and false vocal folds and by increasing the harmonics as well.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.2
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• pp.320-327
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• 2010

The IR signature data of a ship is mainly affected by location, meteorological conditions(atmosphere temperature, wind direction and velocity, humidity etc.), atmospheric transmittance, solar position and ship surface temperature etc. The IR signatures received by a remote sensor at a given temperature and wavelength region is consisted of the self-emitted component directly from the object surface, the reflected component of the solar irradiation at the object surface, and the scattered component by the atmosphere without ever reaching the object surface. Computer simulations for prediction of the IR signatures of ships are very useful to examine the effects of various sensor positions. In this paper, we have acquired the IR signature for different sensor positions by using computer program for prediction of the IR signatures. The numerical results show that the IR signature contrast as compared to the background sea considering the meteorological conditions, solar and sky irradiations.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.5
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• pp.84-91
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• 2008

The spectral radiance received by a remote sensor at a given temperature and wavelength region is consisted of the self-emitted component directly from the object surface, the reflected component of the solar irradiation at the object surface, and the scattered component by the atmosphere without ever reaching the object surface. The IR image of a ship is mainly affected by location, meteorological condition(atmosphere temperature, wind direction and velocity, humidity etc.), atmospheric transmittance, solar position and ship surface temperature etc. Computer simulations for prediction of the IR signatures of ships are very useful to examine the effects of various meteorological conditions. In this paper, we have acquired the IR signature for different meteorological conditions by using two different computer programs. The numerical results show that the IR image contrast as compared to the background sea considering the atmosphere temperature and wind velocity.

• The Journal of Korean Physical Therapy
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• v.22 no.4
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• pp.83-89
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• 2010

Purpose: The goal of this study was to investigate the feasibility for the early diagnosis of inflammatory arthritis by the reconstruction of three-dimensional photoacoustic imaging with a tissue phantom. Methods: Q-switched Nd:YAG laser (l = 532 nm) was applied to a tissue phantom to generate photoacoustic waves, and the acquired photoacoustic signals at different positions around the sample were used to recombine the distribution of the optical absorption and the images were subsequently generated through a reconstruction algorithm. Results: From the acquired photoacoustic signals, the surface andinner core of the phantom was clearly distinguished. Furthermore, the back-projection algorithm was able to reconstruct two-dimensional and three-dimensional photoacoustic images that contained the optical absorption property information of the tissue phantom. Conclusion: The results indicate that the photoacoustic imaging technique has many advantages such as high optical contrast and high acoustic resolution. The acquired images can be used for the early diagnosis of inflammatory arthritis by the structural information obtained from the region of interest.

• Journal of IKEEE
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• v.10 no.1 s.18
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• pp.62-68
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• 2006

In this paper, we propose an adaptation strategy for blind equalizers, which combines a blind algorithm based on high order statistics and the decision directed LMS algorithm. In contrast to 'Stop-and-Go' algorithm, where adaptation is stopped for unreliable signals, the proposed algorithm applies high order statistics (HOS) blind algorithm to the unreliable signals and applies DD-LMS for the reliable signals. The proposed algorithm, named 'Run-and-Go' algorithm, inherits minimum MSE performance of DD-LMS and acquisition ability of blind algorithms. Furthermore, by updating the reliable signal region according to signal quality in each iteration, the convergence speed and acquisition ability is further improved.

• Nuclear Engineering and Technology
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• v.47 no.4
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• pp.454-460
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• 2015

Acoustic emission (AE) is one of the promising methods for detecting the formation of stress corrosion cracks (SCCs) in laboratory tests. This method has the advantage of online inspection. Some studies have been conducted to investigate the characteristics of AE parameters during SCC propagation. However, it is difficult to classify the distinct features of SCC behavior. Because the previous studies were performed on slow strain rate test or compact tension specimens, it is difficult to make certain correlations between AE signals and actual SCC behavior in real tube-type specimens. In this study, the specimen was a AISI 304 stainless steel tube widely applied in the nuclear industry, and an accelerated test was conducted at high temperature and pressure with a corrosive environmental condition. The study result indicated that intense AE signals were mainly detected in the elastic deformation region, and a good correlation was observed between AE activity and crack growth. By contrast, the behavior of accumulated counts was divided into four regions. According to the waveform analysis, a specific waveform pattern was observed during SCC development. It is suggested that AE can be used to detect and monitor SCC initiation and propagation in actual tubes.

• Journal of the Optical Society of Korea
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• v.17 no.3
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• pp.262-268
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• 2013

We study the focusing properties of a two-dimensional square-lattice photonic crystal (PC) comprising silica and germanium partitioned cylinders in air background. The finite difference time domain (FDTD) method with periodic boundary condition is utilized to calculate the dispersion band diagram and the FDTD method incorporating the perfectly matched layer boundary condition is employed to simulate the image formation. In contrast to the common square PCs in which the negative refraction effect occurs in the first photonic band without negative phase propagation, in our suggested model system, the frequency with negative refraction exists in the second band and in near-infrared region. In this case, the wave propagates with a negative phase velocity and the evanescent waves can be supported. We also discuss the dependency of the image resolution and its location on surface termination, source location, and slab thickness. According to the simulation results, spatial resolution of the proposed PC lens is below the radiation wavelength.

• New & Renewable Energy
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• v.3 no.3
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• pp.28-35
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• 2007

In this study, the wave power resources at the three locations [Sokcho, Hupo, and Onsan] on the east coast of Korea were estimated by using the field measurement data and were compared with the results of previous researches. It was found that seasonal variation of the wave power is very significant on the east coast of Korean peninsula. The wave power was the smallest in the summer season at all the locations. At Hupo and Onsan, the highest value of the monthly-averaged wave power was observed in September, probably because the pathways of typhoon in September were close to both locations. At the northest location, Sockcho, in contrast, the monthly highest value of the wave power appeared in January, probably owing to the influence of storm waves driven by Donghae twister. The estimated annual average wave power was 4.5 kW/m at Sokcho, which was about two times larger than those at other two locations. It is noteworthy that this result is completely different from past researches based on wave hindcasting data. In addition, the estimates of wave power by the past researches seemed to be smaller than those of the present study, especially at the northern region of the east coast.

• Parasites, Hosts and Diseases
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• v.39 no.4
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• pp.285-292
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• 2001

The present study aimed to evaluate control efficacy of clonorchiasis by two schemes of repeated treatment with praziquantel at two endemic villages in China. Residents of one village at Guangxi Autonomous Region were treated and examined 6-monthly and of another at Liaoning Province 12-monthly, In residents that took 25 mg/kg x3 (total 75 mg/kg) of Praziquantel every 6 months for one Year the e99 Positive rate showed a significant drop from 69.0% to 17.1%. In contrast, a group of same praziquantel medication once showed a slight marginal decrease in the egg rate from 18.9% to 12.2% after one year Of 39 subjects examined 3 times, 56.4% were cured, 7.7% persistently positive, one (2.6%) reinfected after cure or newly infected, but 25.6% were persistently negative. The present finding suggests that 6-monthly medication with 75 mg/kg of praziquantel should effectively lower the prevalence but incomplete for control of clonorchiasis in heavy endemic areas.