• Applied Chemistry for Engineering
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• v.18 no.1
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• pp.77-83
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• 2007

It is essential that second order nonlinear optical materials have low optical propagation losses in the wavelengths of second harmonic generation for practical applications in waveguides. Three dipolar chromophores substituted with nitro, cyano, and alkyl sulfone as an electron withdrawing group were prepared. The UV-Vis absorption spectra of the cyano and alkylsulfone chromophores showed a blue-shift compared to the nitro chromophore. The introduction of oxadiazole segment in the chromophore structure led to similar spectral shift. The blue-shift can produce low optical loses at second harmonics. The chromophores were successfully attached to a polyimide, yielding side chain polymers. The nonlinear optical property of the prepared optical polymers was determined by measuring electro-optic coefficient at 1.55 mm. The polymers exhibited high glass transition temperature of over $185^{\circ}C$ and thermal stability to $300^{\circ}C$ through differential scanning calorimeter analysis and thermal gravimetric analysis.

• Journal of the Korean Society for Library and Information Science
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• v.28
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• pp.83-107
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• 1995

The purpose of this research is to investigate the attitudes of students, who are used to study at the Library of Duksung Women's University, concerning about the loss and mutilation of books, articles and other research materials m a university library, and to take measures for preventing the library materials from being lost and mutilated. This study made the surveys of student's recognition about the immoral behaviors like larcenous and mutilating acts, the causes of such destructive works and effective preventive measures to keep library materials in good condition, including student's opinion about library services. The investigations were conducted in two times with the same questionnaire on randomly selected 480 students and 540 students of 1989 and 1994 respectively. The sample size is estimated to reach each $10\%$ of the total number of students of 1989 and 1994 in Duksung Women's University. And then, the students were divided into two groups. The one is a group that has had experiences stealing and mutilating the materials from the Library of the University. The other is another group which has done none of them. Thereafter the responses of the two groups are analyzed to compare the differences of the students' behaviors between 1989 and 1994, and thereby finding out important factors inviting the loss and mutilation and accordingly improving effective checks to deter the students from stealing and mutilating the library materials. Some of the research findings suggested in this paper are pointed out as follows: 1) The students who has experienced neither stealing nor mutilating the library materials visited the library more frequently and are more serious about such destructive behavior as stealing and mutilating. 2) The attitudes of the students about services and equipments supplied by the library are slightly different among the students who experienced such immoral activities or not. For example, the experienced students had more preference about an application of self-help duplicating machine being able to use card. 3) To prevent the students from stealing and mutilating the library materials, the non-experienced students demanded an education for them to duly recognize the public interest of the library and also suggested to keep more duplicate materials ready in the library, meanwhile, the experienced students indicated strongly such proposals as strict regulations against stealing and mutilating behaviors, having a correct understanding of costing a lot of time and money to restore the damaged materials to their original state and keeping many duplicates ready in the library. 4) It appears to be that there were different between the experienced and non- experienced students concerning causes invited stealing and mutilated behaviors. 5) Over all, the number of the non-experienced students is more increased in 1994 than that of 1989.

• Korean Journal of Head & Neck Oncology
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• v.13 no.2
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• pp.213-220
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• 1997

Background: Thyroid cancer is a relatively rare neoplasm and its incidence varies geographically and ethnically around the world. Thyroid cancer is the most common endocrine malignancy, but it has a wide spectrum of biologic behavior, histologic appearance, and management. Purpose: The purpose of the study was to analyse and evaluate all aspects of the clinical consideration in thyroid cancer. Method: Between 1986 and 1995, a retrospective analysis of 77 thyrod cancer patients admitted at the Department of Surgery, Hangang Sacred Heart Hospital, Hallym University was made to assess clinical entities. Result: By the pathological classification, the papillary carcinoma was the most common type(83.1%). Male to female ratio was 1 : 5.4 and most prevalent age group was noted from fourth decade to fifth decade(46.8%). The most common duration of illness between the appearance of the symptoms and the treatment was below 6 months(44.2%), and the most common symptom was the palpable mass at the anterior portion of the neck(96.1%). Most cases of the thyroid cancer were appeared as cold nodule in the $^{99m}$Tc-thyroid scan(95.7%). In the site of tumor location, the right and left lobe was distributed similarly. In the extent of tumor, incidence of intrathyroidal location was 41.6%, and that of the metastasis to the cervical lymph nodes was 44.2% and that of the direct capsular invasion was 27.3%, and incidence of both involved case was 13%. Surgical procedures were total thyroidectomy alone in 27 cases(35.1%) or with modified neck dissection in 6 cases(7.8%), or with radical neck dissection in 2 cases (2.6%), near total thyroidectomy alone in 22 cases(28.6%), ipsilateral lobectomy with isthmectomy alone in 12 cases(15.6%) or with modified neck dissection in 1 case(1.3%), and biopsy only in 7 cases(9.1%). The most common postoperative complications were transient hypoparathyroidism(5.2%) and transient unilateral recurrent laryngeal nerve paralysis(5.2%). Conclusion: The major problem of management of thyroid cancer include a wide spectrum of clinical behaviour of this tumor entity, the lack of reliable prognostic factors and lack of an objective assessment of the various treatment modalities. But because of showing the favorable prognosis for most thyroid cancer, appropriate and aggressive management should be recommended.

• Economic and Environmental Geology
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• v.46 no.2
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• pp.105-121
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• 2013

This study introduces integrated approach on detection of a leakage in a sea wall based on remote sensing, electric resistivity survey, electromagnetic survey, and borehole survey for the Seosan A-Region sea wall. The satellite temperature distribution from Landsat ETM+ data identifies water leakage distribution and period by analyzing temperature mixing patterns between sea water and fresh water. Electric resistivity survey provides both horizontal and vertical anomaly distributions over the sea wall showing below average electric resistivity. Electromagnetic survey(electrical conductivity survey) reveals the potential possible leakage areas with minimal background impact by comparing electrical conductivity values between high and low tides. Borehole image processing system confirmed the locations of anomalies identified from the other survey methods and distributions of vertical fracture zones. The integrated approach identified 41.7% of the sea wall being the most probable area vulnerable to water leakage and effectively approximated both horizontal and vertical distribution of water leakage. The integrated analysis of remote sensing, electric resistivity survey, electromagnetic survey and borehole survey is considered to be an optimal method in identifying water leakage distribution, period, and extent of fractures knowledged from the boreholes.

• Journal of Sensor Science and Technology
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• v.11 no.2
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• pp.77-83
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• 2002

In order to get low cost and portability, semiconductor gas sensor need to have low operating temperature and high sensitivity. $Fe_2O_3$ based sensors which were doped with metal oxide catalysts($MoO_3$, $V_2O_5$, $TiO_2$, and CdO) were fabricated by screen printing method. To improve electrical stability of sensors, the $Fe_2O_3$ sensors were annealed in $N_2$ at $700^{\circ}C$ for 2 hours. The $V_2O_5$ doped $Fe_2O_3$ sensor showed about $80{\sim}90%$ sensitivity at alcohol 1,000 ppm and have good selectivity to hydrocarbon gas and tobacco odors. The fabricated sensor and PIC-chip were employed for portable alarm system.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.4
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• pp.191-202
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• 2001

Experiments were conducted on established grassland sward at Gongiam, Kwangju, and Kyung-gi in Korea from 1995 to 1997. The influence of mineral-N fertilizer or animal manure(AW) on herbage dry matter(DM) yield, N yield, the recovery of AM-N, and soil N and organic matter(0M) content in the mixed sward('potomac' orchardgrass, 'fawn' tall fescue, and 'kenblue' Kentuky bluegrass) was investigated. The treatments were replicated three times in a split plot block design. AM(the main plots) was applied at 200kg N ha ' year ' on each plot. The types of AM were cattle feedlot manure(CFM), pig manure fermented with sawdust(PMFS) and Korea native cattle slurry(KNCS). Three levels of mineral-N fertilizer, as urea, ranging from 0 to 200kg N $ha^{-1}\;year^{-1}$ in 100kg increments, were superimposed on each plot. The fertilizers and AM were applied in two equal dressings(the end of March and middle of November). AM and mineral fertilizer had significant effects(p<0.05) on herbage DM and N yields. Herbage yields in KNCS were higher than those in CFM and PMFS(p

• Korean Journal of Food Science and Technology
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• v.43 no.4
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• pp.469-474
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• 2011

Ginger (Zingiber officinale Rosc.) is a well known edible plant that is traditionally used to treat various illnesses related to inflammation and oxidative stress. Steam distillated ginger oil or water extract are mainly used for related products; however, it is unclear whether these fractions contain most of the bioactive compounds or the highest efficacy. This investigated the antioxidant effects of extracts prepared by supercritical fluid extraction (SFE). 6-Gingerol was the most abundant component in hexane fraction of ethanol extract from ginger. The antioxidative properties of SFE oil and Marc ethanol fractions were demonstrated using the 2,20-diphenylpicrylhydrazyl (DPPH) and 2,2'-azinobis 3-ethyl benzothiazoline-6-sulfonic acid (ABTS) radicals scavenging assays. A clear correlation was observed between total polyphenol contents and $RC_{50}$ values in the Marc ethanol fraction. These results indicate that not only SFE oil but the marc after SFE could be good sources for the food industry.

• Journal of the Korea Society of Computer and Information
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• v.15 no.4
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• pp.83-90
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• 2010

In wireless sensor networks, the data transmitted from the sensor nodes are susceptible to corruption by errors which caused of noisy channels and other factors. In view of the severe energy constraint in Sensor Networks, it is important to use the error control scheme of the energy efficiently. In this paper, we presented RS (Reed-Solomon) codes in terms of their BER performance and power consumption. RS codes work by adding extra redundancy to the data. The encoded data can be stored or transmitted. It could have errors introduced, when the encoded data is recovered. The added redundancy allows a decoder to detect which parts of the received data is corrupted, and corrects them. The number of errors which are able to be corrected by RS code can determine by added redundancy. The results of experiment validate the performance of proposed method to provide high degree of reliability in low-power communication. We could predict the lifetime of RS codes which transmitted at 32 byte a 1 minutes. RS(15, 13), RS(31, 27), RS(63, 57), RS(127,115), and RS(255,239) can keep the days of 173.7, 169.1, 163.9, 150.7, and 149.7 respectively. The evaluation based on packet reception ratio (PRR) indicates that the RS(255,239) extends a sensor node's communication range by up about 3 miters.

• Korean journal of food and cookery science
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• v.16 no.5
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• pp.445-452
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• 2000

Antimicrobial activity of Jakyak(Paeonia japonica var. pilosa $N_{AKAI}$) was investigated. Methanol extract of dried Jakyak was fractionated to hexane, chloroform, ethylacetate, butanol and aqueous fraction. Ethylacetate fraction among these fractions showed the highest inhibitory effect on the microorganisms such as B. subtilis, L. monocytogenes, and V. parahaemolyticus at 500 $\mu\textrm{g}$/disc. Ethylacetate fraction was further fractionated into 11 fractions by silica gel column and thin layer chromatography(TLC). The results showed that ethylacetate fractions No. 3, 4 and 5 had the highest antimicrobial activity. They were mixed again, re-separated, and 5 fractions were obtained. Among them, the highest inhibitory effect was obtained in No. 3 fraction, which was identified as cetyl alcohol by HPLC and GC-MS.S.

• Korean Journal of Microbiology
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• v.26 no.3
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• pp.230-236
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• 1988

The distributions of bacterial numbers and activities were studied bimonthly in 1987, at 3 sites in Lade Paro for elucidating the changes by disturbance of aquatic ecosystem. The total bacterial number was $0.3\times 10^{5}-13.1\times ^{5}$ cells/ml. The geterotrophic bacterial number had the variance from $1.9\times 10^{3}$ CFUs/ml to $3.1\times 10^{4}$CFUs/ml and the variation trend was similar to that of the total bacterial number. The proportions of alpha-glucosidase or beta-glucosidase releasing bacteria showed temporal changes rather than spatial changes. The proportions of phosphatase releasing bacteria had the maximum values, 22.7-83.0%, in July. The electron transpory system activity revealed the variation from $480{\mu}gO_{2}$/l/day to $1696{\mu}gO_{2}$/l/day and hagher values at upper stream and in summer. The degradation fraction by phosphatase was 0.4-9.1%/h and increased with temperature. The maximum value of heterotrophic activity was 8.2%/h in summer. Eventhough the distributions of total bacteria and heterotrophic bacteria were affected by the water disturbance but microbial activities and proportions of the specific enzume releasing bacteria were not affected.