• Progress in Medical Physics
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• v.13 no.2
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• pp.69-73
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• 2002

Exposure measurement data with parallel plate ionization chambers were known to depend on the polarity ($k_{pol}$) effect. In this work, the polarity effect were investigated for three parallel plate ionization chambers with different volume. The ionization chamber was fabricated using acrylic plate for the chamber medium and printed circuit board for electrical configuration. The various sizes of the sensitive volumes designed so far were 0.9, 1.9, and 3.1 co. High voltage generator was fabricated using the conventional 9 V batteries to apply the high voltage (300-500 V) to the electrode of the parallel plate ionization chamber. The gap between two electrodes ranged from 3, 6, and 10mm. As the result of our experiment, the polarity effect was within 0.5% in photon beam and 1% to 3.5% in the electron beams. Among electron beams, 16 MeV beam, which had highest energy, showed less polarity effect than electron beams with other energies.

• Restorative Dentistry and Endodontics
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• v.16 no.1
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• pp.87-105
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• 1991

The purpose of this experiment was to measure the leaking and solubility of commonly used dental restorative materials - Silux plus (CS), Hi-pol (CH), Clearfil F-II, Fissureseal (FS), Glass-Ionomer cement Fuji Type II (GI), Amalgam Cavex 68 (AM), Zinc Phosphate Cement (ZP) and gutta-percha (GP) and investigate the relation between the solubility and marginal leakage. Disc-shape specimens were fabricated with each material and dipped into deionized water, 0.01M lactic acid and 0.005M KOH solution, thus the total ionic concentrations in each solution was measured with ion chromatograph after 1, 3, and 7 days, respectively. For the solubility test, each specimen was immersed in 0.001M and 0.01M lactic acid for 24 hours, respectively and total weight loss was calculated. Also, Zn leaking through the margin of restorations was measured. The obtained results were as follows: 1. The amounts of eluted ion from the eight materials were most in 0.01M lactic acid and least in deionized water. 2. Of the eight materials, the fluoride release was greatest for glass ionomer cement (GI) in 0.01 M lactic acid after 7 days. 3. In analysis of the divalent cation, Mg was eluted most for zinc phosphate cement (ZP) and Ca for Clearfil F-II (CF) in 0.01M lactic acid after 7 days. 4. In analysis of transition metals, Cu and Zn were detected only. 5. The solubility rate of eight materials was greater in 0.01M lactic acid than in 0.001M for 24 hours, for zinc phosphate cement (ZP) the rate was greatest (5.4%) in 0.001M lactic acid, and amalgam least (0.01%). 6. The Zn concentration of restorative material with Z.P.C base was greater in 0.01M lactic acid than in 0.001M lactic acid.

• Proceedings of the Korea Society for Simulation Conference
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• 1993.10a
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• pp.12-13
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• 1993

컴퓨터를 이용한 모의 실험 방법은 과학 및 공학 분야뿐만 아니라 경제,사회 현상등에도 널리 적용될 수 있는 유용한 도구이다. 그 중에서도 연속체계 모의 실험은 미분 방정식으로 모델링되는 시스템을 대상으로 하는 경우가 맡으며, 이를 위하여 그동안 맡은 연속체계 모의 실험 언어들이 개발되었다. 그러나 그들은 대부분 사용하기가 복잡하여 사용자 편의성을 고려한 모의 실험 언어에 대한 필요성이 증대되었다. 본 연구에서는 사용자에개 최대한 편의성을 제공하는 연속체계 모의 실험 언어인 PCSL (Postech Continuous-system Simulation language)을 개발하였다. PCSL 프로그램은 프로그램 헤더, 상수 정의부, 함수 정의부, 매개 변수 정의부, 초기화 선언부, 모델 정의부, 종료 조건 선언부, 출력 선언부 등으로 나누어 진다. 그리고 출력으로는 계산 결과를 파일에 저장, 흑은 수치로 인쇄하거나 그래프로 그려서 보여준다. PCSL 처리 시스템은 모델 정의부에서 주어진 미분방정식을 해석해서 digital-analog simulation 기법으로 풀 수 있는 형태로 변환하는 번역기와 이렇게 변환된 형태의 미분방정식과 여러 가지 조건들을 고려해서 C 프로그램을 생성해주는 생성기, 생성된 C 프로그램을 실행시켜서 그 결과를 얻는 실행기,그리고 사용자에게 편리한 입출력 방법을 제공하는 사용자 인터페이스로 구성된다. 번역기에서는 모델로 주어진 미분방정식의 종류를 결정한 후에 이들을 digital-analog simulation 기법으로 풀 수 있는 형태로 변환한다. 생성기에서는 번역기의 결과를 받고,프로그램 상의 여러 가지 조건들을 고려해서 C 프로그램을 생성한다. 여기서 생성된 C프로그램은 미분방정식을 포함하는 ‘f.c'와 조건들을 포함하는'main.h', 그리고 digital-analog simulation 기법을 이용하는 모의 실험 알고리즘을 구현한 'main.c'로 구성된다. 그리고 실행기에서는 생성기에서 생성한 C 프로그램을 실행시켜서 결과를 얻는다. 여기에서 필요로 하는 PCSL 프로그램의 내응은 종료 조건 선언부, 출력 선언부 등이다. 마지막으로 사용자 인터페이스는 사용자가 간편하게 PCSL 프로그램을 입력할 수 있게 도와주며 모의 실험 결과를 쉽게 화면상에 보여주기 위한 것이다. 이 때에 사용자가 원하면 계산 결과를 그래프로 그려서 보여주는 기능과 화면에 보이는 결과를 프린터로 출력할 수 있는 기능을 제공한다. 실형 결과로는 먼저 선형 상미분방정식의 예로 mass-damper-spring system, 비선형 상미분방정식의 예로는 van der Pol 방정식, 연립 상미분방정식의 예로는 mixing tank problem 등을 보였으며, 그의 공학에서 일어나는 여러 가지 문제들도 다루었다.

• The Korean Journal of Food And Nutrition
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• v.10 no.3
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• pp.407-413
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• 1997

The antimutagenic mechanism of cinnamaldeyde on mutagenesis induced by 4-nitroquinoline-1-oxide(4-NQO) and N-metyl-N'-nitro-N-nitrosoguanidine (MNNG) was investigated in various DNA repair-deficient strains, E. coli B/r and K-12 series. Cinnamaldehyde did not show any effects not only on the $\beta$-galactosidase activities of GW1060 and GW1103(recA441) which synthesizes $\beta$-galactosidase consitutively at 41$^{\circ}C$ but also on that of GW1107[lexA51 (Def)] in which the SOS response always occur. These results suggest that cinnamaldehyde dose not change the function of RecA which positively controls the SOS response as well as not acting as the repressor like LexA. In addition, no inhibitory effect of cinnamaldehyde was observed on the growth of Trp+ revertant and the delay of viable cell growth was also not found by adding cinnamaldehyde. Despite the decrease in the number of revertants, a significant increase in survival of 4-NQO treated cells was observed in E. coli WP2s(uvrA), ZA159($\Delta$uvrB) and TK603(uvrA). But these effects disappeared in excision-proficient strain WP2(uvrA+) and lexA-deficient strains(CM561 and CM611). The enhancement of survival was not found in WP67(uvrA polA) deficient in polymerase I which ligates the gap between complementary DNA. From the above results, we assume that cinnamaldehyde might show antimutagenic effect by enhancing an error-free recombinational repair system.

• Journal of the Institute of Convergence Signal Processing
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• v.18 no.1
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• pp.13-20
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• 2017

In this paper, we evaluate the basic test results of the 32 Gbps observational equipment introduced as the back-end system for the wideband VLBI (Very Long Baseline Interferometry) observation of KVN (Korean VLBI Network). Radio astronomers want to make a large radio telescope that has excellent performance in order to observe the superfine structure of a celestial body, but a lot of money is needed. Therefore, in order to increase the sensitivity, the performance improvement of the receiving system and the method of observing the wide frequency bandwidth are introduced. To do this, we adopted a wideband sampling method for converting analog signals to digital with ultra-fast speeds and a wideband sampler for performing digital filtering in order to observe a wide observational frequency bandwidth. The wideband sampler (OCTAD-K) supports up to 16 Gsps-2bits sampling and supports a variety of observational bandwidth using digital filtering techniques. In particular, it is designed to support KVN's 4-frequency simultaneous observation system and VERA(VLBI Exploration of Radio Astrometry)'s 2-beam observation system. It can also support polKVN(Korean VLBI Network), KaVA(KVN and VERA Array), 32Gbps Direct Sampler, Digital Filter, Widebandarization observations and supports the standard VDIF(VLBI Data Interchange Format) format of observed data. In this paper, the performance of the system and the problem solving are described in detail after performing the factory inspection and field test before the system is introduced.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1621-1621
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• 2001

The quality of sugarcane grown on the NE Australian tropical coast ($16^{\circ}$15'- $18^{\circ}$15' S Lat.) has declined markedly in the past seven years. This has been linked to dilution of mill-supply cane with increasing levels of non mature-stalk material consisting of leaves and sucker culms. The prime research objective was to examine the transition from the pre-harvest, in-field crop to harvested material sent for processing, in terms of quality and crop fraction proportions. A secondary objective was to quantify the effects of preharvest-season crop habit and culm condition on crop quality. Ten quadrat samples from each of 54 random crop sites (17 in 1999 and 37 in 2000), covering a wide range of variables (cultivar, crop class, and edaphic, topographic, climatic, and temporal factors) were collected immediately before harvest. Samples were partitioned into four fractions:- sound and unsound mature stalks (culms), sucker culms, and extraneous matter (leaves). Material harvested from each site was sampled and partitioned into four fractions:- sound and unsound billets (culm pieces), culm-spindle pieces, and leaf. In 2000, before harvest, 14 additional sites were sampled monthly, on three occasions, from March - June. Erect and non-erect culms were divided into sound and unsound classes. All samples were disintegrated and presented to a remote reflectance module of a scanning spectrophotometer using the BSES large cassette module. Near infra-red spectroscopic (NIS) analyses were developed for the rapid determination of quality components (Brix, commercial cane sugar (CCS), fibre, moisture, and polariscope reading). Calibrations for three material groups (culm (n = 639), non-culm (n = 496), and combined) were developed for all components using the 1999 data set. Two sub-sets (n = 178, and 190) of about 10% of the preharvest-season and harvest populations scanned in 2000 also were subjected to full routine laboratory analyses. The 1999 combined calibrations were excellent, but the culm calibrations produced consistently lower standard errors. Non-culm calibrations were marginally better than the combined for only CCS and pol. reading. Analysis of the 2000 culm data with calibrations using all 1999 and 2000 culm data resulted in better predictions relative to the 1999 culm calibrations. This also was true for the combined calibrations. Assessment of quality components in pre- and post-harvest sugarcane using NIS calibrations was more cost effective than using routine laboratory techniques. Outcomes from this NIS-facilitated research will have important economic consequences for the Australian sugarcane industry. Potential CCS present in mature culms is being discounted by dilution with leaves and sucker culms, threatening farm viability. The results question the efficacy of current harvesting technology. The CCS of harvested cane is improved only marginally over that of the in-field crop. Current harvesting technology requires either supplementary, innovative pre-mill processing or a design revolution to improve mill-supply cane quality, and therefore whole of industry economics. NIS-facilitated analyses, before the harvest season, highlighted the benefits of growing erect, sound crops. Loss of CCS then, can be minimized only by a combination of crop improvement and agronomic solutions, applied as part of sound on-farm management.

• Journal of the Korean Applied Science and Technology
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• v.8 no.1
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• pp.27-34
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• 1991

동백종실유(冬栢種實油)에서 컬럼크로마토그래피로 지질(脂質) 성분(成分)을 상호(相互) 분리(分離)하였다. 여기서 얻은 트리글리세리드의 일부(一部)를 취하여 알칼리로 가수분해(加水分解)하거나 또는 pancreatic lipase로 가수분해(加水分解) 하여, 트리글리세리드의 구성(構成) 지방산(脂肪酸) 또는 1, 3- 위치(位置)와 2-위치(位置)에 급합(給合) 한 지방산(脂肪酸) 조성(組成)을 조사(調査)하였다. 나머지 트리글리세리드는 16% $AgNO_3$ TLC로 이중결합선(二重結合敾)별로 나누었으며, 이렇게 나누어진 분획(分劃)을 다시 HPLC로 PN별로 재분획(再分劃) 하였다. 여기서 얻어진 획분(劃分)들 중 PN이 같은 것은 모두 모아서 알칼리 가수분해(加水分解)로 PN의 총지방산(總脂肪酸) 조성(組成)을, pancreatic lipase로 1,3 위치(位置)에 결합선(結合敾)한 지방산(脂肪酸)의 조성(組成)을 조사(調査) 하였다. 여기서 얻어진 결과(結果)로 부터 구성(構成) 트리그리셀리드 분자종(分子種)을 산출(算出)하였더니 다음과 같은 결과(算出)를 얻었다. 1) 종실유(種實油)는 투명(透明)한 액체(液體)로 그 함량(含量)이 73.5%였으며, 그 중 트리글리세리드가 94.8%, 극성(極性) 지질(極性)이 2.0%, 탄화(炭化) 수소(水素)가 1.8%였다. 2) $AgNO_3$-TLC로 트리글리세리드를 분획(分劃)하였더니 5개의 획분(劃分)을 얻었으며, 대부분(大部分)의 트리글리세리드가 이중(二重) 결합선(結合敾) 3${\sim}$5개인 band 2와 band 3에 80% 이상 존재(存在)하였다. 3) $AgNO_3-TLC$에서 얻은 각 획분(劃分)은 모두가 HPLC상에서 PN 46, 48 및 50으로 나누어졌으며 전체(全體) 분획(分劃)에서 PN 48이 78.13%로 제일 많았으며, 다음으로 PN 50이 12.04%였으며, PN 46이 9.83%였다. 4) 전체(全體) 트리글리세리드 분자종(分子種) 중에서 0.1mol% 이상을 차지하고 있는 분자종(分子種)이 43종(種)이었으며, OOO와 POO가 각각 39.8mol%와 25.8mol%로 제일 많았으며, 그 다음으로 OPO가 5.5 mol%, OOL가 4.8 mol%, POS가 3.9mol%, SOO가 3.5mol%. POL이 3.0mol%였다. 또 동백종실유(冬栢種實油)에 존재(存在)하는 트리글리세리드의 분자종(分子種)의 조성(組成)은 1,3-random, 2-random 분포설(分布說)에 따라 구성(分布說)되어 있었다.

• Korean Journal of Medicinal Crop Science
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• v.4 no.3
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• pp.231-235
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• 1996

The experiment was conducted to determine pollen morphology of Chinese peony and its germination. The results were obtained as following ; Pollen shpae was usually large ellipse and the pol­len germination rate of Eui-seong Peony line was 71% which was lower than that of other Peony lines. In a bud, the pollen began to be observed on $7{\sim}9days$ before flowering and as getting on for flowering time, normal pollen and germination rates were higher. The pollen germination and elongation beganat 30 minutes after incubation on artificial medium and were completed after $2{\sim}3\;hours$. As the storage time went on, the pollen life span was shortened. The germination rate was 51% at 8 days-storage of room temperature. The germination rate was 48% ad 43% at 95 day-storage in $0^{\circ}C$ and $-15^{\circ}C$, respectively.

• Korean Journal of Remote Sensing
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• v.36 no.2_2
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• pp.325-335
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• 2020

Forest canopy height can be used for estimate of above-ground forest biomass (AGB) by means of the allometric equation. The remote locations and harsh conditions of mangrove forests limit the number of field inventory data stations needed for large-scale modeling of carbon and biomass dynamics. Although active and passive spaceborne sensors have proven successful in mapping mangroves globally, the sensors generally have coarse spatial resolution and overlook small-scale features. Here we generate a 12 m spatial resolution mangrove canopy height map from TanDEM-X data acquired over the world largest intact mangrove forest located in the Sundarbans. With single-pol. TanDEM-X data from 2011 to 2013, the proposed technique makes use of the fact that the double-bounce scattering that occurs between the water and mangrove trees yields water surface level elevation over mangrove forest areas, thus allowing us to estimate forest height with the assumption of an underlying flat topography. Our observations have led to a large-scale mangrove canopy height map over the entire Sundarbans region at a 12 m spatial resolution. Our canopy height estimates were validated with ground measurements acquired in 2015, a correlation coefficient of 0.83 and a RMSE of 0.84 m. With globally available TanDEM-X data, the technique described here will potentially provide accurate global maps of mangrove canopy height at 12 m spatial resolution and provide crucial information for understanding biomass and carbon dynamics in the mangrove ecosystems.

• Journal of Dental Anesthesia and Pain Medicine
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• v.22 no.3
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• pp.217-226
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• 2022

Background: Intraosseous anesthesia is the process by which an anesthetic solution, after penetration of the cortical bone, is directly injected into the spongiosa of the alveolar bone supporting the tooth. This study aimed to compare the effectiveness of the traditional inferior alveolar nerve block (IANB) and computerized intraosseous anesthesia in the surgical extraction of impacted lower third molars, compare their side effects systemically by monitoring heart rate, and assess patients' a posteriori preference of one technique over the other. Methods: Thirty-nine patients with bilaterally impacted third molars participated in this study. Each patient in the sample was both a case and control, where the conventional technique was randomly assigned to one side (group 1) and the alternative method to the contralateral side (group 2). Results: The traditional technique was faster in execution than anesthesia delivered via electronic syringe, which took 3 min to be administered. However, it was necessary to wait for an average of 6 ± 4 min from the execution to achieve the onset of IANB, while the latency of intraosseous anesthesia was zero. Vincent's sign and lingual nerve anesthesia occurred in 100% of cases in group 1. In group 2, Vincent's sign was recorded in 13% of cases and lingual anesthesia in four cases. The average duration of the perceived anesthetic effect was 192 ± 68 min in group 1 and 127 ± 75 min in group 2 (P < 0.001). The difference between the heart rate of group 1 and group 2 was statistically significant. During infiltration in group 1, heartbeat frequency increased by 5 ± 13 beats per minute, while in group 2, it increased by 22 ± 10 beats per minute (P < 0.001). No postoperative complications were reported for either technique. Patients showed a preference of 67% for the alternative technique and 20% for the traditional, and 13% of patients were indifferent. Conclusion: The results identified intraosseous anesthesia as a valid alternative to conventional anesthesia in impacted lower third molar extraction.