• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.974-977
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• 1999

PSN-PT 2성분계 압전세라믹스의 상도로부터 유전적, 압전적 특성이 양호한 MPB (Morphotropic phase boundary)부근의 조성을 선택하여 도너 도펀트인 $Nb_{2}O_{5}$와 억셉터 도펀트인 $Fe_{2}O_{3}$를 각각 $0{\sim}0.9wt%$ 첨가하여 유전 및 압전특성을 비교, 연구해보았다. 시편모두 $1250^{\circ}C$ 이상에서 이론밀도의 96%이상의 값을 얻을 수 있었고 상온, 1kHz에서 $Fe_{2}O_{3}$의 경우 0.1wt% 첨가된 시편에서 ${\varepsilon}_r$=2054의 최대 비유전율이 나타났으며, 0.7wt% 첨가된 시편에서는 $tan{\delta}$=0.49%의 최소 유전 손실값을 얻었다. $Fe_{2}O_{3}$가 0.1wt%, 0.3wt%로 첨가되었을 때 각각 $K_p$=58%, Qm=222의 값을 얻을 수 있었다.

• Analytical Science and Technology
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• v.8 no.4
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• pp.623-630
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• 1995

Silicone rubber-based sodium-selective membranes are developed for solid-state ion sensors. It was shown that the potetiometric performance of SR-based membranes are greatly dependent on the type of neutral carriers employed; among the three ionophores, N,N,N',N'-tetracyclohexyl-1,2-phenylenedioxydiacetamide (ETH 2120), bis[(12-crown-4)methyl]dodecylmethylmalonate (D12C4DMM) and monensin methyl ester (MME), examined, only ETH 2120 was compatible with the SR-based matrix. Addition of about 20 wt% plasticizer to the SR-based matrix provided the resulting membranes with potentiometric properties essentially equivalent to those of the corresponding PVC-based membranes. Owing to the strong adhesive strength of SR-based membranes, the CWEs coated \vith those membranes exhibited long lifetime with conventional electrode-like performance. Blending of PU into the SR matrix increased the lifetime of CWEs from two weeks to one month.

• The Journal of the Acoustical Society of Korea
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• v.16 no.1
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• pp.81-87
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• 1997

In this paper, a new pre-processing method for the recognition of single vowels by use of spectrum envelope is presented. We use new extraction method of a spectrum envelope using the diffusion filter bank. By dividing analysis band of a diffusion filter bank into subbands, we decreased the number of diffusion process. And, by increasing the number of difference, we got higher selectivity. As a result of them, we reduced the total processing time, and got higher enhancement of discrimination. By getting 88.3% of average recognition rate for single vowels of natural voice through computer simulation. We confirmed it to be useful for speech recognition which use spectrum analysis of the voice signal to have many frequency components.

• ETRI Journal
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• v.41 no.2
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• pp.176-183
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• 2019

Spectrum sensing plays an important role in spectrum sharing. Energy detection is generally used because it does not require a priori knowledge of primary user (PU) signals; however, it is sensitive to noise uncertainty. An order statistics (OS) detector provides inherent protection against nonhomogeneous background signals. However, no analysis has been conducted yet to apply OS detection to spectrum sensing in a wireless channel to solve noise uncertainty. In this paper, we propose a robust spectrum sensing scheme based on generalized order statistics (GOS) and analyze the exact false alarm and detection probabilities under noise uncertainty. From the equation of the exact false alarm probability, the threshold value is calculated to maintain a constant false alarm rate. The detection probability is obtained from the calculated threshold under noise uncertainty. As a fusion rule for cooperative spectrum sensing, we adopt an OR rule, that is, a 1-out-of-N rule, and we call the proposed scheme GOS-OR. The analytical results show that the GOS-OR scheme can achieve optimum performance and maintain the desired false alarm rates if the coefficients of the GOS-OR detector can be correctly selected.

• Steel and Composite Structures
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• v.39 no.3
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• pp.261-274
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• 2021

In a railway bridge, the CRTS II slab ballastless track is subjected to interlayer connection failures, such as void under slab, mortar debonding, and fastener fracture. This study investigates the influences of interlayer connection failure on the safe operation of high-speed trains. First, a train-track-bridge coupled vibration model and a bridge-track deformation model are established to study the running safety of a train passing a deformed bridge with interlayer connection failure. For each type of the interlayer connection failure, the effects of the failure locations and ranges on the track irregularity are studied using the deformation model. Under additional bridge deformation, the effects of interlayer connection failure on the dynamic responses of the train are investigated by using the track irregularity as the excitation to the vibration model. Finally, parametric studies are conducted to determine the thresholds of additional bridge deformations considering interlayer connection failure. Results show that the interlayer connection failure significantly affects the running safety of high-speed train and must be considered in determining the safety thresholds of additional bridge deformation in the asset management of high-speed railway bridges.

• Journal of the Korean Society for Nondestructive Testing
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• v.18 no.3
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• pp.163-171
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• 1998

Near/far field length and directivity of transducers were investigated for the improvement and evaluation of the detectability of flaws in a disc. The reference block is fabricated for the disc of stage 6 in Yonggwang unit 1. The near/far field and directivity of an ultrasonic transducer with the center frequency of 5MHz were calculated for the inspection of the disc. These values showed good agreements with the experimental results. In the system composed of a wedge and a disc, those are evaluated theoretically and experimentally for the specimen with the artificial flaws of the size 2mm and 4mm and an ultrasonic transducer with the center frequency 5MHz and diameter 0.5inch. The detectability of keyway-flaw and detectable region for inspection were evaluated by using both tangential $45^{\circ}$ and $90^{\circ}$ transducers located at the distance of 53mm and 75mm from the disc hub, respectively.

• Toxicological Research
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• v.6 no.1
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• pp.41-49
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• 1990

Aconiti Tuber is the root of Aconitum sp (Ranunclaceae) which has been considered as one of the most important medicinal plant having cordiotonic, diuretic and analgesic effect. On the other hand, it has been known that Aconiti Tuber contained toxic agent, aconitine alkaloids so that only processed Aconiti Tubers have been used as herbal drug traditionally. For the safety evaluation of processed Aconiti Tuber, quantitative determination of aconitine and acute, subacute toxicity test were performed on 5 commercial processed Aconiti Tubers. Arapid and precise method using HPLC has been developed for the separation and determination of aconitine. Samples were extracted with hydrochloric acid (pH3) and hot water decoction. In case of d-HCL extracts, the contents of aconitine were from 0.08 mg/g to trace. But in case of hot water decoction extracts, the contents of aconitine were not detected. For the investigation of Aconiti Tuber toxicity in rats, hot water decoction samples and methanol extracts were tested. 1) Acute toxicity test Hot water decoction sample and methanol extracts from Aconiti Tuber did not show any toxic effects in rats by an oral administration. $LD_50values of 2 extracts were above 10.0 g/kg. 2) Subacute toxicity study In the repeated administration study, hot water decoction samples were given orally to Sprague-Dawlay rats for 2 week at daily doses of 5.0 g/kg. The results are as follows; No toxic manifestation, body weight changes and lethality were observed during wxperimental period. There were no significant changes in serum enzyme activities such as GOT, GPT, LDH, ALP between treated and control groups. However CPK values were decreased in the Subuja-treated group. (P<0.01). In addition, no gross and microscopic changes were noted in Aconiti Tuber-treated groups.

• Journal of the Korean Society of Food Culture
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• v.13 no.4
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• pp.363-381
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• 1998

Food goods traded between Korea and Japan during the middle period of the Cho Sun era included Insam (Jinseng), rice, beans, honey, perilla oil, starch, adlay, walnuts, pine nuts, jujubes, hazelnuts, and dired chestnuts as exports ; and pepper as imports. The number of Japanese envoies that visited regularly was one thousand five hundred people a year. The receptions that were held for them during the middle period equaled those of the first term of the Cho Sun era, but these receptions were only held in Pu-san. The expense of daily meals was broken down into 8 grades ranging from \129,300 to 2133. The daily meals included Jo-ban (breakfast), Jo-seok-ban (breakfast and dinner), and Ju-jeom-shim (lunch) for the Japanese who visited regularly. During the course of a year, the total amount spent on daily meals was put at a billion won. The banquet style meals included Ha-seon-da-rye (a welcome tea party), Ha-seon-yeon (a welcome banquet), No-cha-yeon (a banquet that was held on the street), and Ye-dan-da-rye (a drink banquet that was held when silk was offered as a gift). It also included Byeol-yeon (a banquet out of the dordinary), Sang-seon-yeon (a farewell banquet), and Myong-il-yeon (a banquet that was held on a national holiday). The banquet style meals were composed of Ceon-tack (to set a table for dinner), Sang-hwa (a flower that was put on the food), Kwan-hwa (to offer a flower when a banquet was held), Ju-9-jan (the ninth wine glass), Dae-seon (meat), music, and Jung-bae-rye (a banquet that was held again after a banquet). The Cho Sun government held banquets forty five times for the Japanese, the food expense for the banquets was put at two hundred and thirty million won.

• The Journal of Internal Korean Medicine
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• v.31 no.4
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• pp.693-705
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• 2010

Objectives : The water extract of Daechilgi-tang(DCGT) has traditionally been used for treatment of qi stagnation(氣滯), which is considered to be one of the important causes of neuronal disease in oriental medicine. However, little is known about the mechanism by which DCGT protects neuronal cells from brain cell damages. Methods and Results : The author tested the mechanism of the cytoprotective effect of DCGT on glutamate -stimulated rat C6 glial cells. DCGT significantly protected C6 glial cells from glutamate in MTT assay. Pre-treatment of C6 glial cells with DCGT markedly inhibited the DNA fragmentation of C6 cells induced by glutamate. Glutamate increased the generation of reactive oxygen species(ROS) and intracellular calcium level in C6 glial cells. However, pre-treatment with DCGT markedly suppressed the increase of ROS generation and intracellular calcium accumulation induced by glutamate. Among apoptosis signaling mediators, DCGT markedly increased the expression level of Bcl2 in glutamate-treated cells. It also inhibited the cleavage of caspase-3 and PARP proteins by glutamate in C6 glial cells. Conclusions : These results suggest that DCGT protects brain cells from glutamate cytotoxicity through inhibition of ROS generation and activation of apoptosis signaling pathway as well as induction of the anti-oxidant system.

• The Journal of Internal Korean Medicine
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• v.30 no.4
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• pp.880-892
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• 2009

Objectives : This study is about a comparison of controlled and uncontrolled hypertension groups regarding pulse shape and quality of life. We aimed to find out if pulse shape would be able to help with hypertension treatment and care. Methods : We surveyed "controlled and uncontrolled hypertension patients" using SF-36, HTN QoL (measurement scale for the quality of life in hypertensive patients) and 3-D MAC pulse analyzer for pulse shape. Results : The uncontrolled hypertension group tended to have a sink pulse in the left cun. right guan & chi parts compared to the controlled hypertension group. Within the controlled hypertension group, patients who had a float pulse shape in both guan parts had a higher quality of life than patients who had a normal pulse shape. And the patients who had a normal pulse shape in both chi parts had a higher quality of life than patients with a slow or fast pulse shape. Within the uncontrolled hypertension grouP. the patients who had a normal pulse shape in right guan part had a higher quality of life than those with a choppy pulse shape. Nevertheless, these results were limited to only a few quality of life issues and were inconsistent in relation to specific pulse shapes. Conclusion : If we have more samples and better methods for collecting data, we will have better results, allowing us to improve our ability to predict and treat hypertension.