• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.547-548
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• 2006

In order to realize the commercial application of HTSC materials, it is necessary to develop the fabrication process of high Tc oxide superconductor materials with desired shape and for practical application and high critical current density as well as good mechanical strength which can withstand high lorenz force generated at high magnetic field. Much studies have been concentrated to develop the fabrication technique for high critical current density but still there are a lot of gap which should be overcome for large scale application of HTSC materials at liquid nitrogen temperature. Recently some new fabrication techniques have been developed for YBaCuO bulk superconductor with high mechanical strength and critical current density. In this project, the establishment of fabrication condition and additive effects of second elements were examined so as to improve the related properties to the practical use of YBaCuO superconductor, and we reported the production of the YBaCuO high Tc superconductor by the pyrolysis method.

• Journal of Community Nutrition
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• v.7 no.4
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• pp.215-219
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• 2005

Oxygen radical absorbance capacity(ORAC) is known to be a sensitive and simple method to determine total antioxidant capacity(TAC) in biological samples. While TAC has received great attention with its relation to pathogenesis in the progression of several diseases, little is known about association of ORAC with metabolic risk factors. The aim of this study is to evaluate the relationship between ORAC and serum lipid profiles, fasting glucose and anthropometric measures. One hundred seventeen volunteers participated in the study. Perchloric acid treated serum was used to determine $ORAC_{pca}$. Mean$ORAC_{pca}$ of subjects whose serum total cholesterol(TC) concentrations were $\geq$ 200 mg/dl was significantly(P < 0.05) higher than that of subjects whose TC concentrations were < 200mg/dl. There were significantly positive correlations between $ORAC_{pca}$ and serum concentrations of TC(P < 0.05) and low density lipoprotein (LDL) cholesterol(P < 0.01). The positive relation between cholesterol concentrations and $ORAC_{pca}$ in serum may suggest an elevated TAC against oxidative stress associated with the cardiovascular risk factors. (J Community Nutrition 7(4): $215\∼219$, 2005)

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.3
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• pp.419-425
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• 2001

In land mobile communications, multipath fading is one of the key factors which affect the system performance. Some extensive studies have been carried out to improve the degraded performance under this fading channels. The PSAM channel compensation method using channel fading estimation is widely used and TCM is a combined coding and modulation technique that has been shown to provide significant coding gain without increasing the transmission bandwidth. In this paper, we analyze the performance of PSA-TC-8PSK which combines PSAM and TCM over frequency nonselective fading channels. To estimate channel fading, Wiener filter which minimizes error variance is used as compensation method and we analyze the affects on the system performance of the number of filter taps, period of the pilot symbol frame, and the Doppler frequency. In addition, we consider the symbol timing recovery circuit which can be implemented in the full-digital method and analyze the effects of symbol timing error on the system performance.

• Journal of Advanced Navigation Technology
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• v.22 no.2
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• pp.64-69
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• 2018

Automatic test equipment for field maintenance of aircraft mounted equipment is effective for integrated design when operating a small number of aircraft for special purposes. The integrated automatic test equipment identifies commonly used interfaces and is used for branching or generating routes for each unit under test specific inspection. High-precision signals such as RTD, TC, and analog voltage can cause measurement errors due to conduction resistance during signal branching and connection when generating branches and paths. The measurement error caused by the resistance of the wire leads to a lot of restrictions in designing the equipment to be inspected. In this paper, we propose a method of calibrating highly accurate signals of an integrated automatic inspection equipment that minimizes measurement errors of analog voltage and high - precision signals.

• The Korean Journal of Nuclear Medicine
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• v.33 no.3
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• pp.247-261
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• 1999

Purpose: The aim of this study was to evaluate the normal values of regional cerebral blood flow (rCBF) and cerebrovascular reserve (CVR) in normal children to aged volunteers using Tc-99m HMPAO, Materials and Methods: Thirty four right-handed normal volunteers (20 males, 14 females, mean age $40.3{\pm}24.9$ years, range 4 to 82 years) were underwent rost/acetazolamide (ACZ) brain SPECT using Tc-99m HMPAO and the sequential injection and subtraction method. rCBF was estimated on the basis of a semiquantitative approach by means of right/left ratio, region/cerebellum and region to whole brain ratios in (rental, parietal, temporal, and occipital lobes, basal ganglia, thalami, and cerebellum. CVR was measured by means of % perfusion increase calculated as % mean count change compared to rest rCBF in each regions. Results: Mean values of right to left ratios range from 1.004 to 1.018, rCBF was highest in cerebellum and lowest in basal ganglia and thalami. Frontal and temporal rCBF decreased while occipital and thalamic rCBF increased according to age. No sexual difference of rCBF was noted. Mean CVR was $29.9{\pm}12.9%$. Mean CVR significantly increased to late teens, and declined thereafter. After 6th decade, CVR in both frontal lobes, left parietal lobe and right basal ganglia decreased significantly with advancing age. There was no sexual difference of CVR. Conclusion: Quantitative assessment of CVR was possible by ACZ Tc-99m HMPAO brain SPECT. It revealed that rCBF and CVR changed according to age in normal Korean volunteers. There was no sexual difference.

• Journal of the military operations research society of Korea
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• v.35 no.2
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• pp.1-14
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• 2009

During wartime, the Air Force have to plan where, and how much, and what need to be distributed to surrounding local area from a chosen central bases. Each base, which has surplus more than needed amount of a certain material collected from near area of the base, is expected to distribute such surplus to other bases in shortage of it. By sending such surplus to other bases in shortage of the material, every base may get sufficient amount of all kinds of materials needed for each base during wartime. Because number of items of materials needed in each military bases during wartime are usually quite large and the frequencies of delivery from a place to other place are also pretty large if each item is delivered from a surplus place to other places in shortage, the Head Quarter of Air Force or the Logistics Command will face to difficulty to decide a reasonable delivery plan between bases for efficient and fast allocation of all materials needed to all bases during wartime. Therefore, this study suggests a solving algorithm with an established TC (transfer center: collecting and distributing center for all materials) to solve such a distribution and transportation problem.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.851-856
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• 2003

The study on the new measurement method of room acoustics is now in process in the ISO TC43/SC2/WG24 New standard(WD 18233) is dealing with the MLS, swept sinusoidal signal and impulse. This working group is composed of more than 20 specialists in 10 countries and the convener is professor J.H.Rindel in technical university of Denmark. The meeting of WG24 was held in the DIN, Berlin at 23rd. this september and the results was sent to the secretary of ISO TC43/SC2 for the circulation. Brief information of ISO/WD18233 and the result of this meeting is given here.

• Transactions on Electrical and Electronic Materials
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• v.6 no.6
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• pp.289-293
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• 2005

We have fabricated superconductor ceramics by chemical process. A high Tc superconductor with a nominal composition of $Bi_2Sr_2Ca_2Cu_3O_y$ was prepared by the organic metal salts method. Experimental results suggest that the intermediate phase formed before the formation of the superconductor phase may be the most important factor. The relation between electromagnetic properties of Bi HTS and external applied magnetic field was studied. The electrical resistance of the superconductor was increased by the application of the external magnetic field. But the increase in the electrical resistance continues even after the removal of the magnetic field. The reason is as follows; the magnetic flux due to the external magnetic field penetrates through the superconductor and the penetrated magnetic flux is trapped after the removal of the magnetic flux.

• The Korean Journal of Nuclear Medicine Technology
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• v.19 no.2
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• pp.74-80
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• 2015

Purpose Breast lymphoscintigraphy is an important technique to present for body surface precisely, which shows a lymph node metastasis of malignant tumors at an early stage and is performed before and after surgery in patients with breast cancer. In this study, we evaluated several methods of body outline imaging to present exact location of lesions, as well as compared respective exposure doses. Materials and Methods RANDO phantom and SYMBIA T-16 were used for obtaining imaging. A lesion and an injection site were created by inserting a point source of 0.11 MBq on the axillary sentinel lymph node and 37 MBq on the right breast, respectively. The first method for acquiring the image was used by drawing the body surface of phantom for 30 sec using $Na^{99m}TcO_4$ as a point source. The second, the image was acquired with $^{57}Co$ flood source for 30 seconds on the rear side and the left side of the phantom, the image as the third method was obtained using a syringe filled with 37 MBq of $Na^{99m}TcO_4$ in 10 ml of saline, and as the fourth, we used a photon energy and scatter energy of $^{99m}Tc$ emitting from phantom without any addition radiation exposure. Finally, the image was fused the scout image and the basal image of SPECT/CT using MATLAB$^{(R)}$ program. Anterior and lateral images were acquired for 3 min, and radiation exposure was measured by the personal exposure dosimeter. We conducted preference of 10 images from nuclear medicine doctors by the survey. Results TBR values of anterior and right image in the first to fifth method were 334.9 and 117.2 ($1^{st}$), 266.1 and 124.4 ($2^{nd}$), 117.4 and 99.6 ($3^{rd}$), 3.2 and 7.6 ($4^{th}$), and 565.6 and 141.8 ($5^{th}$). And also exposure doses of these method were 2, 2, 2, 0, and $30{\mu}Sv$, respectively. Among five methods, the fifth method showed the highest TBR value as well as exposure dose, where as the fourth method showed the lowest TBR value and exposure dose. As a result, the last method ($5^{th}$) is the best method and the fourth method is the worst method in this study. Conclusion Scout method of SPECT/CT can be useful that provides the best values of TBR and the best score of survey result. Even though personal exposure dose when patients take scout of SPECT/CT was higher than another scan, it was slight level comparison to 1 mSv as the dose limit to non-radiation workers. If the scout is possible to less than 80 kV, exposure dose can be reduced, and also useful lesion localization provided.

• Tuberculosis and Respiratory Diseases
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• v.55 no.3
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• pp.280-286
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• 2003

Background : $^{99m}Technetium$ methylene diphosphonates($^{99m}Tc$ MDP) bone scintigraphy is current method of choice for the detection of bone metastases, but whole body $^{18}F$-fluoro-deoxy-D-glucose positron emission tomography($^{18}FDG$ PET) offers superior spatial resolution and improved sensitivity. So we compared whole body $^{18}FDG$ PET with $^{99m}Tc$ MDP bone scintigraphy in patients with skeletal metastases from lung cancer. Patients and Methods : Ninety-two patients with lung cancer taken $^{18}FDG$ PET together with a $^{99m}Tc$ MDP bone scintigraphy within 1 month between March 2000 and March 2003 were investigated retrospectively. Results : The sensitivity, specificity and accuracy of the $^{99m}Tc$ MDP bone scintigraphy versus $^{18}FDG$ PET for the detection of bone metastases in lung cancers were 59% vs 82%, 71% vs 94%, and 68% vs 91%, respectively. In the diagnosis of bone metastases from lung cancer, $^{18}FDG$ PET was statistically superior to $^{99m}Tc$ MDP bone scintigraphy in its specificity and accuracy(p<0.0001). Conclusions : Whole body $^{18}FDG$ PET may be useful in detecting bone metastases among patients with lung cancer.