• Journal of Sensor Science and Technology
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• v.31 no.6
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• pp.371-375
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• 2022

Antimony-doped tin oxide (ATO) thin films, one type of transparent conductive oxide (TCO) films, were prepared on a SiO₂-coated glass substrate with different substrate temperatures by a radio-frequency magnetron sputtering system. Structural, optical, and electrical characteristics of the deposited ATO films were analyzed using X-ray diffraction, scanning electron microscopy, alpha-step, ultraviolet-visible spectrometer, and Hall effect measurement. The substrate temperature during deposition did not affect the basic crystal structure of the films but changed the grain size and film thickness. The optical transmittance of the ATO films deposited at different substrate temperatures was over 70%. The lowest sheet resistance and resistivity were 8.43 × 10² Ω/sq, and 0.3991 × 10^-2 Ω·cm, respectively, and the highest carrier concentration and mobility were 2.36 × 10²¹ cm^-3 and 6.627 × 10^-2 cm²V^-1s^-1, respectively, at a substrate temperature of 400 ℃.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.4
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• pp.348-352
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• 2022

Resistive switching behaviors of a co-sputtered zinc silicate thin film (ZnO and SiO₂ targets) have been investigated. We fabricated an Ag/ZnSiO_x/highly doped n-type Si substrate device by using an RF magnetron sputter system. X-ray diffraction pattern (XRD) indicated that the Zn₂SiO₄ was formed by a post annealing process. A unique morphology was observed by scanning electron microscope (SEM) and atomic force microscope (AFM). As a result of annealing process, 50 nm sized nano clusters were formed spontaneously in 200~300 nm sized grains. The device showed a unipolar resistive switching process. The average value of the ratio of the resistance change between the high resistance state (HRS) and the low resistance state (LRS) was about 106 when the readout voltage (0.5 V) was achieved. Resistance ratio is not degraded during 50 switching cycles. The conduction mechanisms were explained by using Ohmic conduction for the LRS and Schottky emission for the HRS.

• Journal of the Korean Vacuum Society
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• v.7 no.s1
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• pp.106-117
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• 1998

Fluorocarbonated-SiO2 films were deposited on p-type Si(100) substrate using FSi$(OC_2H_5)_3$ (FTES), and $O_2$ mixture gases by a helicon plasms source. High density $O_2$/FTES/Ar plasma of ~$10^{12} \textrm{cm}^{-3}$ is obtained at low pressure (<3mTorr) with RF power above 900 W in the helicon plasma source. Optical emission spectroscopy (OES) is used to study the relation between the relative densities of the radicals and the film properties. The FTES and $O_2$ gases are greatly dissociated at the helicon mode that is launched at the above threshold plasma density. FTIR and XPS spectra shows that the film has Si-F, and C-F bonds during the formation process of the film which may lower the dielectric constant greatly. The relative dielectric constant, leakage current density, and dielectric breakdown voltage are about 2.8, $8\times10^{-9}\textrm{A/cm}^2$, and > 12 MV/cm, respectively.

• Steel and Composite Structures
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• v.46 no.2
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• pp.153-173
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• 2023

Rectangular concrete-filled steel tubular (RCFST) column, a type of concrete-filled steel tubular (CFST), is widely used in compression members of structures because of its advantages. This paper proposes a robust machine learning-based framework for predicting the ultimate compressive strength of RCFST columns under both concentric and eccentric loading. The gradient boosting neural network (GBNN), an efficient and up-to-date ML algorithm, is utilized for developing a predictive model in the proposed framework. A total of 890 experimental data of RCFST columns, which is categorized into two datasets of concentric and eccentric compression, is carefully collected to serve as training and testing purposes. The accuracy of the proposed model is demonstrated by comparing its performance with seven state-of-the-art machine learning methods including decision tree (DT), random forest (RF), support vector machines (SVM), deep learning (DL), adaptive boosting (AdaBoost), extreme gradient boosting (XGBoost), and categorical gradient boosting (CatBoost). Four available design codes, including the European (EC4), American concrete institute (ACI), American institute of steel construction (AISC), and Australian/New Zealand (AS/NZS) are refereed in another comparison. The results demonstrate that the proposed GBNN method is a robust and powerful approach to obtain the ultimate strength of RCFST columns.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.7
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• pp.889-895
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• 2007

This study investigated the quality characteristics of red ginseng cheonggukjang development by a various of concentration of red ginseng extract and powder to enhance its acceptability and functional properties. In the cheonggukjang added with red ginseng extract, viscous substances, reducing sugars, and fibrinolytic activity showed higher values by the addition of red ginseng extract. The standard crude saponin content of products containing red ginseng was evaluated, and found to be suitable in cheonggukjang added with 4% red ginseng extract. In the cheonggukjang added with red ginseng powder, viscous substances, reducing sugars, and fibrinolytic activity showed a similar tendency to the cheonggukjang added with red ginseng extract. Amino type nitrogen and ammonia type nitrogen decreased by increasing the addition of red ginseng powder, and the crude saponin content of cheonggukjang with the addition of 14% red ginseng powder was suitable, in terms of manufacturing standards for products containing red ginseng. Dependent on the addition time of red ginseng in cheonggukjang, viscous substances, reducing sugars, fibrinolytic activity, amino type nitrogen, and ammonia type nitrogen showed no differences based on the addition time; however, for crude saponin content, the cheonggukjang with red ginseng added before fermentation showed a higher saponin content than the cheonggukjang with red ginseng added after fermentation. The ginsenosides $Rg_{1}$, Re, Rf, $Rh_{1}$, $Rg_{2}$, $Rb_{1}$, Rc, $Rb_{2}$, Rd and $Rg_{3}$ were detected, but ginsenoside content did not show significant difference according to addition time. In conclusion, the addition amount of red ginseng in cheonggukjang for optimum fermentation was concentration of 4% (w/w), which showed the best results in quality characteristics.

• Proceedings of the KSPS conference
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• 1997.07a
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• pp.11-25
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• 1997

This presentation will focus on building basic English Prosodic Skills which are very useful and helpful for Japanese learners of English. The focus first will be on recognizing the seven basic nuclear tones, analysing intonation structures, distinguishing intonation patterns and then on the way of improving speaking ability using sufficient verbal contents of intonation (mini-dialogue). My presentation deals mainly with some difficulties which Japanese learners of English have in the field of RP intonation, It is chiefly concerned with identifying, describing and analysing tone-group sequences. It sometimes happens that Japanese learners of English can pronounce isolated bounds correctly and read phonetic symbols sufficiently, bet have difficult problems in carrying out accurate prosodic features. The use of wrong intonation is sometimes the cause of misunderstanding of speaker's attitude, connotation and shades of meaning, etc.. However accurately students can pronounce the nuclear tone or tone-group of English, they have to learn how to connect tone-groups properly for suitable sequences in respect to meaning or implication. We are faced with the complicated theory of RF intonation on the one hand and difficult realization of it on the other. Japanese learners of English have special difficulties in employing "rising tune" and "falling + rising tune". If students are taught pitch movements by indicating dots graphically between two horizontal lines, they can easily understand the whole shape of pitch movements. In this presentation, I illuminate several tone-group sequences which are very useful for Japanese learning English intonation. Among them, four similar Pitch Patterns, such as, (1) (equation omitted)- type, (2) (equation omitted) - type, (3) (equation omitted) - type and (4) (Rising Head) (equation omitted)- type are clarified and other important tone-group sequences aye also highlighted from the point of view of teaching English as a foreign language. The intonation theory, tone marks and technical terms are, in all essentials, those of Intonation of Colloquial English by O'Connor, J. D. and Arnold, G. F., Longman, 2nd ed., 1982. The changes of tone are shown graphically between two horizontal lines representing the ordinary high and low zones of the utterance. A.C.Gimson (1981:314) : The intonation of English has been studied in greater detail and for longer than that of any other language. No definitive analysis, classifying the features of RP intonation, has yet appeared (though that presented by O'Connor and Arnold (1973) provides the most comprehensive and useful account from the foreign learner's point of view).

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.7
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• pp.661-668
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• 2004

A novel method to reject the spurious signals which are occurred at Weaver-type low-IF transmitter was proposed in this paper. The spurious signals are generated by the gain and phase imbalances of I/Q channel or imperfect characteristics of 90$^{\circ}$ phase shifter in local oscillator for I/Q channel source. By deriving the gain and phase-based functions from RF spurious signal with the channel imbalance information, the lie channel imbalances were deduced as functions with magnitude and sign dependent on I/Q channel imbalance degree. The proposed method compensates the estimated I/Q channel imbalances by correlation values between the down-converted signal obtained by squaring the output signal itself using a simple mixer and the modified baseband signal. By comparing two signals after A/D conversion, the magnitude and sign of each type of imbalances can be determined separately and simultaneously. Based on the I/Q channel imbalance compensation, the spurious signals can be reduced by adjusting the gain and phase values of I or Q channel signal. The way to estimate the channel imbalances of the up-conversion mixer was presented and verified by using theoretical derivations and computer simulations.

• Journal of Oral Medicine and Pain
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• v.17 no.2
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• pp.75-86
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• 1992

Of the many first-occuring major manifestations of Behcet's disease, the oral ulcer is most frequently observed, shows the highest mean recurrence rate, and the longest mean duration period. A study of the relationship between mechanical irritation buy local factors and the recurrence of oral ulcers was carried out to see if there is a correlation. The subjects chosen for the study were 81 patients who were referred to the Department of Oral Diagnosis at Yonsei University Dental Hospital from the Behcet clinic of Severace Hospital after being diagnosed as Behcet's disease patients. 1. By Shimuzu's classification, possible type was the most numerous with 55.55% ; while suspected type was 19.76% ; incomplete type, 17,28% ; and complete type, 7.41% were observed in that order. The male to female ration was 1 to 1.61, and the average age of onset was 17.63 years. 2. Oral ulcers developed most frequently on the tongue (48.28%), and lip(23.15%), buccal mucosa (20.69%), palate\pharynx(4.43%), and gingiva(3.45%) also showed ulceration. 3. 38.27% of the patients were HSV positive : 27.16% were CRP positive ; 12.34% were ASO positive ; 9.87% were RF positive ; and 3.7% were ANA positive. 4. According to the answers to the survey, fatigue(85.18%) was most frequently associated with Behcet's diseage. Trauma by tooth brushing (22.22%), un specified reasons (20.98%), hard food chewing (12.35%), and irritation by dentition and/or prosthesis (13.58%) were observed in association with Behcet's disease. 23.46% had a history of tonsilitis. 5. Oral ulcers on the anterior part of tongue and buccal mucosa were associated with local irritatants. 6. Oral ulcers on the lip and posterior portion of tongue were not associated with local irritants. Local irritation by dentition and oral ulcer on the anterior part of tongue and buccal mucosa was observed to coexit with one another : in other words, lo9cal factors can act to cause of recurrence of an oral ulcer and to delay the healing process in Behcet's disease. Therefore, elimination of local factors along with systemic therapy must be recommended when treating oral ulcers.

• Reproductive and Developmental Biology
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• v.35 no.2
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• pp.151-157
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• 2011

Clinical arthritis is typically divided into rheumatoid arthritis (RA) and osteoarthritis (OA). Arthritis-induced muscle weakness is a major problem in aged people, leading to a disturbance of balance during the gait cycle and frequent falls. The purposes of the present study were to confirm fiber type-dependent expression of muscle atrophy markers induced by arthritis and to identify the relationship between clinical signs and expression of muscle atrophy markers. Mice were divided into four experimental groups as follows: (1) negative control (normal), (2) positive control (CFA+acetic acid), (3) RA group (CFA+acetic acid+type II collagen), and (4) aging-induced OA group. DBQA/1J mice (8 weeks of age) were injected with collagen (50 ${\mu}g/kg$), and physiological (body weight) and pathological (arthritis score and paw thickness) parameters were measured once per week. The gastrocnemius muscle from animals in each group was removed, and the expression of muscle atrophy markers (MAFbx and MuRF1) and myosin heavy chain isoforms were analyzed by reverse transcription-polymerase chain reaction. No significant change in body weight occurred between control groups and collagen-induced RA mice at week 10. However, bovine type II collagen induced a dramatic increase in clinical score or paw thickness at week 10 (p<0.01). Concomitantly, the expression of the muscle atrophy marker MAFbx was upregulated in the RA and OA groups (p<0.01). A dramatic reduction in myosin heavy chain (MHC)-$I{\beta}$ was seen in the gastrocnemius muscles from RA and OA mice, while only a slight decrease in MHC-IIb was seen. These results suggest that muscle atrophy gene expression occurred in a fiber type-specific manner in both RA- and OA-induced mice. The present study suggests evidence regarding why different therapeutic interventions are required between RA and OA.

• Korean Journal of Veterinary Research
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• v.37 no.3
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• pp.541-546
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• 1997

There are two conserved regions with a significantly high amino acid sequence homology among the A subunits of STX, SLTs and ricin. To produce an inactive Verotoxin-2 (VT-2), two different mutants, pE167D and pDE5A, were constructed by site-directed mutagenesis, respectively, on the basis of the previous reports that two regions lie within the active-site clefts of the A subunits of ricin and STX family. The cytotoxicity ($10^3$ $CD_{50}/ml$) of VT-2 holotoxin with E167D mutation was reduced by $10^3$-fold compared with wild-type level. In addition, VT-2 with DE5A ($Trp_{202}GlyArgIleSer_{206}$) deletion mutation showed a significantly low cytotoxicity ($10^1$ $CD_{50}/ml$), resulting in $10^5$- and $10^2$-fold reductions, respectively, compared with the wild-type and E167D mutatant. SDS-PAGE for protein samples showed a 33-kDa band corresponding to the A subunit of VT-2. These results indicate that reduction in cytotoxic activity was affected not by amount of VT-2 protein produced but by mutation.