• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.279-279
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• 2011

나노 입자를 이용한 비휘발성 메모리 소자의 전기적 특성 향상을 위하여 일함수가 Si 보다 큰 금속, 금속산화물, 금속 실리사이드 나노입자를 이용한 다양한 형태의 메모리 구조가 제안되어져 왔다.[1] 특히 이와 같은 나노 부유 게이트 구조에서 터널 절연막의 구조를 소자의 동작 속도를 결정하는데 이는 터널링 되어 주입되는 전자의 확률에 의존하기 때문이다. 양자 우물에 국한된 전하가 누설되지 않으면서 주입되는 전자의 터널링 확률을 증가시키기 위하여, dielectric constant 와 barrier height를 고려한 다양한 구조의 터널 절연막의 형태가 제안 되었다.[2-3] 특히 낮은 전계에서도 높은 터널링 확률은 메모리 소자의 동작 속도를 향상시킬 수 있다. 본 연구에서는 n형 Si 기판위에 Si3N4 및 HfAlO를 각각 1.5 nm 및 3 nm 로 atomic layer deposition 방법으로 증착하였으며 3~5 nm 지름을 가지는 $TiSi_2$ 및 $WSi_2$ 나노 입자를 형성한 후 컨트롤 절연막인 $SiO_2$를 ultra-high vacuum sputtering을 사용하여 20 nm 두께로 형성 하였다. 마지막으로 $200{\mu}m$ 지름을 가지는 Al 전극을 200 nm 두께로 형성하여 나노 부유 게이트 커패시터를 제작하였다. 제작된 소자는 Agilent E4980A precision LCR meter 및 HP 4156A precision semiconductor parameter analyzer 를 사용하여 전기용량-전압 및 전류-전압 특성분석을 하여 전하저장 특성 및 제작된 소자의 터널링 특성을 확인 하여 본 연구를 통하여 제작된 나노 부유 게이트 커패시터 구조가 메모리 소자응용이 가능함을 확인하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.479-479
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• 2011

Flexible inverters based on complementary thin-film transistor (CTFTs) are important because they have low power consumption and other advantages over single type TFT inverters. In addition, integrated CTFTs in flexible electronic circuits on low-cost, large area and mechanically flexible substrates have potentials in various applications such as radio-frequency identification tags (RFIDs), sensors, and backplanes for flexible displays. In this work, we introduce flexible complementary inverters using pentacene and amorphous indium gallium zinc oxide (IGZO) for the p-channel and n-channel, respectively. The CTFTs were fabricated on polyimide (PI) substrate. Firstly, a thin poly-4-vinyl phenol (PVP) layer was spin coated on PI substrate to make a smooth surface with rms surface roughness of 0.3 nm, which was required to grow high quality IGZO layers. Then, Ni gate electrode was deposited on the PVP layer by e-beam evaporator. 400-nm-thick PVP and 20-nm-thick ALD Al2O3 dielectric was deposited in sequence as a double gate dielectric layer for high flexibility and low leakage current. Then, IGZO and pentacene semiconductor layers were deposited by rf sputter and thermal evaporator, respectively, using shadow masks. Finally, Al and Au source/drain electrodes of 70 nm were respectively deposited on each semiconductor layer using shadow masks by thermal evaporator. Basic electrical characteristics of individual transistors and the whole CTFTs were measured by a semiconductor parameter analyzer (HP4145B, Agilent Technologies) at room temperature in the dark. Performance of those devices then was measured under static and dynamic mechanical deformation. Effects of cyclic bending were also examined. The voltage transfer characteristics (Vout- Vin) and voltage gain (-dVout/dVin) of flexible inverter circuit were analyzed and the effects of mechanical bending will be discussed in detail.

• Applied Biological Chemistry
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• 제37권2호
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• pp.105-109
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• 1994

꾸지 뽕나무의 줄기껍질로부터 P388 tumor cell line에 대한 세포 성장 저해활성과 흰쥐 간 microsome 분획의 과산화 지질을 사용하여 $Fe^{++}/\;ascorbate$법으로 측정한 결과 세포 성장 저해활성과 항산화활성을 갖는 5개의 flavonoid계 화합물을 분리하였다. 분리된 화합물의 구조분석을 실시한결과 각종 spectral data와 보고된 문헌에 의하여 taxifolin, orobol, eriodictyol, dihydrokaempferol, steppogenin으로 각각 동정되었다. 이 화합물들의 항산화활성은 $IC_{50}$이 각각 6, 3, 3, >50, $10\;{\mu}g/ml$이었고 taxifolin을 제외한 P388 cell line에 대한 세포 성장저해는 각각 $IC_{50}$이 0.18, 3.3, 15, $6.2\;{\mu}g/ml$이었다. 한편 Escherichia coli BE 1186, Salmonella thyphimurium SL 1102, Staphylococcus aureus IFO 12732, Staphylococcus aureus R 209, Candida albicans에 대해서는 항균활성을 나타내지 않았다.

• Journal of Biosystems Engineering
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• 제27권5호
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• pp.391-398
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• 2002

During handling unitized products, they are subjected to a variety of environmental hazards. Shock and vibration hazards are generally considered the most damaging of the environmental hazards on a product and it may encounter while passing through the distribution environment. A major cause of shock damage to products is drops during manual handling. The increasing use of unitization of pallets has been resulted in a reduction of the shock hazards. This has caused an increasing interest in research focused on vibration caused dam age. Damage to the product by the vibration most often occurs when a product or a product component has a natural frequency that falls within the range of the forcing frequencies of the particular mode of transportation being used. Transportation vibration is also a major cause of fruit and vegetable quality loss due to mechanical damage. This study was conducted to determine the vibration characteristics of the corrugated fiberboard bones for packages of pears, and to investigate the degree of vibration injury of the pears in the boxes during the simulated transportation environment. The vibration tests were performed on an electrohydraulic vibration exciter. The input acceleration to exciter was fixed at 0.25 G for a single container resonance test and 0.5 G for the vertical stacked container over the frequency range from 3 to 100 Hz. Function generator (HP-33120A) was connected by wire to the vibration exciter for controlling the input acceleration at a continuous logarithmic sweep rate of 1.0 octave per min. The peak frequency and acceleration on the single box test were 22.02 Hz, 1.5425 G respectively, and these values on the vertical stacked boxes were observed from the bottom box 19.02, 18.14, 16.62 and 15.40 Hz and 2.2987, 3.7654. 5.6087, and 7.9582 G, respectively. The pear in the bottom box had a slightly higher damage level than the fruit packed in the other stacked boxes. It is desirable that the package and transportation system has to be so designed that 15∼20 Hz frequency will not occur during the transportation environment.

• 보건교육건강증진학회지
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• 제24권2호
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• pp.15-28
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• 2007

Objectives: In this paper, the survey on internet usage patterns of health consumers was conducted and analyzed in order to determine internet health information assessment criteria for providing correct consumer health information on web-sites. Methods: By using a survey questionnaire with 16 questions on general information and 20 questions on internet health information, data were collected from September 16 to 25, 2005 from 476 participants through an internet web site, http://www.hp.go.kr. Frequency analysis, t-test, and multiple regression were used in order to analyze the difference in assessment criteria, factors influencing assessment criteria, factors influencing user satisfaction, etc. Results: General characteristics of the study population were: the persons over age 40 were the smallest age group; women were accounted for 74.2%; and the persons with average income were the largest income group; and the persons with average health status were the largest health group. Most widely used health information were: exercise, disease, and diet, in order. There was significant difference(p=.001) in importance of assessment criteria between the persons in medical institutions and the persons not in medical institutions. There was no significant difference in other assessment criteria. We also found that contents of websites and easy to use were more important factors than elucidation of information providers and information sources including speciality of information in quality assessment criteria of internet health information. Discussion and Conclusion: Results of this paper were compared with the previous studies from the literatures. Contrary to the previous studies in the literature, there was significant difference in importance of assessment criteria between the persons in medical institutions and the persons not in medical institutions. In order to apply the study results to develop health contents for consumer, there is a need for further upgrade the proposed assessment criteria based on expert opinion.

• Journal of Ginseng Research
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• 제41권2호
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• pp.180-187
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• 2017

Background: The incidence of halitosis has a prevalence of 22-50% throughout the world and is generally caused by anaerobic oral microorganisms, such as Fusobacterium nucleatum, Clostridium perfringens, and Porphyromonas gingivalis. Previous investigations on the structure-activity relationships of ginsenosides have led to contrasting results. Particularly, the antibacterial activity of less polar ginsenosides against halitosis-related bacteria has not been reported. Methods: Crude saponins extracted from the Panax quinquefolius leaf-stem (AGS) were treated at $130^{\circ}C$ for 3 h to obtain heat-transformed saponins (HTS). Five ginsenoside-enriched fractions (HTS-1, HTS-2, HTS-3, HTS-4, and HTS-5) and less polar ginsenosides were separated by HP-20 resin absorption and HPLC, and the antimicrobial activity and mechanism were investigated. Results: HPLC with diode-array detection analysis revealed that heat treatment induced an extensive conversion of polar ginsenosides (-Rg1/Re, -Rc, -Rb2, and -Rd) to less polar compounds (-Rg2, -Rg3, -Rg6, -F4, -Rg5, and -Rk1). The antimicrobial assays showed that HTS, HTS-3, and HTS-4 were effective at inhibiting the growth of F. nucleatum, C. perfringens, and P. gingivalis. Ginsenosides-Rg5 showed the best antimicrobial activity against the three bacteria, with the lowest values of minimum inhibitory concentration and minimum bactericidal concentration. One major reason for this result is that less polar ginsenosides can more easily damage membrane integrity. Conclusion: The results indicated that the less polar ginsenoside-enriched fraction from heat transformation can be used as an antibacterial agent to control halitosis.

• 한국식품과학회지
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• 제29권3호
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• pp.522-526
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• 1997

두유를 제조할 때 부산물로 발생하는 대두 침지액 중에 함유된 isoflavone을 흡착수지인 HP-20을 이용하여 분리하고 회수하는 실험을 실시하였다. 대두 침지액 중에는 genistein과 daidzein이 각각의 배당체 형태인 genistin과 daidzin으로 존재하였으며, 이들의 농도는 $0.083{\pm}0.019\;mM$, $0.110{\pm}0.017\;mM$이었다. 흡착수지로 흡착하여 회수하는 데 대두 침지액의 pH가 가장 큰 영향을 미쳤으며, pH 4.0에서 흡착되는 정도가 가장 높았다. daidzin보다는 genistin이 더 강하게 흡착되었다. 또한 용출속도는 SV가 10까지는 회수율에 영향을 주지 않았으며, 칼럼의 직경과 높이의 비율도 어느 정도 영향을 주었다. 이 방법을 이용하여 대두 침지액 중에 함유된 genistin과 daidzin을 각각 85%, 70% 정도 회수할 수 있었으며, 이때 대두 saponin도 함께 회수되었다.

• 약학회지
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• 제42권2호
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• pp.153-158
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• 1998

Calcium hydrogen phosphate was synthesized by reacting calcium chloride and sodium hydrogen phosphate solution in this study. It is well known that the particle size and yield o f calcium hydrogen phosphate produced is greatly affected by the synthetic conditions such as the reactant concentration, reaction temperature, reacting fine, mole ratio and drying temperature, etc. The purpose of this study is to investigate the optimum synthesis condition from the viewpoint of yield and sedimentation volume of the prepared calcium hydrogen phosphate powder according to a randomized complete block design proposed by G.E.P. Box and K.B. Wilson. It was found that the optimum synthetic conditions of calcium hydrogen phosphate were as follows: It was found that optirnum temperature range of reactant solutions was $28-38^{\circ}C$ and $32-42^{\circ}C$ respectively, on the viewpoint of yield and sedimentation volume. The optimum concentration range of reactant solutions was 5.5-10.0% and 6.9-7.4% respectively, on the viewpoint of yield and sedimentation volume. The optimum mole ratio of $CaCl_2$ to $Na_2HPO_4$ was in the range of 1.2-2.0 and the optimum reacting time range was 8.5-11.0 minutes. The optimum drying temperature range was $39-41^{\circ}C$ from the viewpoint of yield, but it was $39-43^{\circ}C$ on the basis of sedimentation volume. Crystallographic analysis to X-ray diffraction patterns of commercially available ecalcium hydrogen phosphate and calcium hydrogen phosphate samples prepared in this study suggested that all samples tested belonged to monoclinic crystal system characteristic of $CaHP0_4{\cdot}2H_20$ crystals.

• 한국동물위생학회지
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• 제36권2호
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• pp.139-145
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• 2013

Porcine respiratory disease complex (PRDC) continues to be a significant economic problem to the swine industry. In order to elucidate the etiology of PRDC including porcine circovirus type 2 (PCV2), porcine reproductive and respiratory disease syndrome virus (PRRSV), swine influenza virus (SIV), Mycoplasma hyopneumoniae (MH), Pasteurella multocida (PM) and Actinobacillus pleuropneumoniae (APP) in Namwon, the 455 lung samples were randomly collected from slaughtered pigs, examined gross lesions indicative of respiratory disease of lung and classified the lung lesion according to the severity of lung lesions. Two hundred pigs lung tissues with pneumonic lesions were examined for pathogen by PCR. As a result, the numbers of pneumonic lesions were 357 (78.5%), mean pneumonic score ($mean{\pm}SD$) was $2.03{\pm}0.90$ and the highest gross lesion according to stages was 1 (11~20%). In detection of pathogens, PCV2, PRRSV, SIV, MH, APP and PM were positive in 76.5%, 5.0%, 6.0%, 9.0%, 4.5% and 6.0%, respectively and PCV2-MH was the most detected causative pathogens of PRDC in co-infection. In the serological test for PRRSV, PCV2, MH, APP2, APP5, HP and PM, showed high antibody positive rates 93% or more.

• 한국작물학회지
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• 제26권4호
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• pp.293-297
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• 1981

맥류시험에 있어서 표본추출 체계를 확립하기 위하여 1979/80년 맥류연구소의 포장에서 실시한 몇가지 소맥재배양식에 대한 표본단위의 크기 및 주어진 정도를 위한 표본수 결정을 시도하였던 바 그 결과를 요약하면 다음과 같다. 1. 소맥의 수수에 대한 변이계수는 휴입광철파를 제외하고는 맥류수량의 평균변이계수와 거의 같았다. 2. 수수의 변이계수와 표본단위의 크기에 대한 회귀계수는 유입광철파를 제외하고 모두 1% 수준에서 유의성을 보였다. 3. 표본단위의 크기는 재배양식에 따라 차이가 크며 변이계수 15%를 허용한다면 협폭파, 관행 및 Drill 파는 각각 0.40, 0.17 및 0.11$m^2$, 로 추정되며 답리작의 유입광철파는 0.55$m^2$, 로 추정되었다. 4. 표본단위간 변이가 심하여 시험오차의 분산성분이 영인 조건하에서 CV=12%를 위해서 2반복인 경우는 구당 2개의 표본단위, 4반복민 경우는 구당 1개의 표본단위로 충분한 것으로 추정되었다.