• Title/Summary/Keyword: Host layer

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A Stable and Efficient Host Material Having Tetraphenylsilane for Phosphorescent Organic Light Emitting Diodes

  • Park, Hyung-Dol;Kang, Jae-Wook;Lee, Deug-Sang;Kim, Ji-Whan;Jeong, Won-Ik;Park, Young-Seo;Lee, Se-Hyung;Go, Kyung-Moon;Lee, Jong-Soon;Kim, Hyong-Jun;Kim, Jang-Joo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.503-505
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    • 2008
  • A host material containing tetraphenylsilane, 9-(4-triphenylsilanyl-(1,1'4,1")-terphenyl-4"-yl)-9H-cabazole (TSTC), was synthesized for green phosphorescent organic emitting diodes. $Ir(ppy)_3$ based OLEDs using TSTC host and DTBT (2,4-diphenyl-6-(4'yl)-1,3,5-triazine) hole blocking layer (HBL) showed the maximum external quantum efficiency of 19.8 %, the power efficiency of 59.4 lm and high operational stability with a half lifetime of 160,000 h at an initial luminance of $100\;cd/m^2$.

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Helicobacter pylori Infection and Vitamin C: Past, Present and Future Perspectives (Helicobacter pylori 감염과 비타민 C: 과거, 현재, 미래)

  • Youn, Hee-Shang;Rhee, Kwang-Ho
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.11 no.sup1
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    • pp.83-92
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    • 2008
  • Helicobacter pylori is the causative agent of chronic gastritis and has a role in the pathogenesis of peptic ulcer diseases, and gastric cancer. There have been reports suggesting a close link between these gastroduodenal disorders and a state of vitamin C deficiency. In this paper, the past, present and future perspectives on H. pylori infection and vitamin C will be discussed under the following view points. Since the ecological niche of H. pylori is the mucus layer and intercellular junctions of the gastric epithelium, the various kinds of host inflammatory cells motivated by the local and systemic immune responses cannot eliminate the microorganisms. When the invading foreign body is not removed, despite full activation of defense mechanisms, adverse consequences of the immune responses develop on the host gastric mucosa. The reasons for the body vitamin C depletion could be explained as follows; 1) the increased vitamin C consumption by increased oxygen free radical production through the prolonged hypersensitivity reactions in the gastric mucosa, 2) the increased vitamin C oxidation by the nitrite which is formed from nitrate reduction by the intragastric bacteria proliferated in the hypochlorhydric gastric cavity, 3) the strong ${\gamma}$-glutamyltranspeptidase activity of H. pylori which depletes the glutathiones in gastric mucosa. Depletion of glutathiones in the stomach favors irreversible oxidative destruction of ascorbic acid. Both persistent inflammatory burdens in the stomach by H. pylori and resultant vitamin C depletions synergistically and uninhibitedly might aggravate the hypothetical sequence of gastric carcinogenesis: atrophic gastritis${\rightarrow}$intestinal metaplasia${\rightarrow}$dysplasia${\rightarrow}$gastric adenocarcinoma. High intake of vitamin C could reverse the hypothetical sequence of the gastric carcinogenesis via direct and indirect effects on H. pylori and host-parasite relationships.

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Fabrication and Characterization of Blue OLED using GDI Host-Dopant Phosphors (GDI 호스트-도펀트 형광체를 이용한 청색 OLED의 제작과 특성 평가)

  • Jang, Ji-Geun;Shin, Se-Jin;Kang, Eui-Jung;Kim, Hee-Won;Chang, Ho-Jung;Oh, Myung-Hwan;Kim, Young-Seop;Lee, Jun-Young;Gong, Myoung-Seon;Lee, Young-Kwan
    • Korean Journal of Materials Research
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    • v.16 no.4
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    • pp.253-256
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    • 2006
  • The blue emitting OLEDs using GDI host-dopant phosphors have been fabricated and characterized. In the device fabrication, 2-TNATA [4,4',4'-tris(2-naphthylphenyl-phenylamino)- triphenylamine] as a hole injection material and NPB [N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine] as a hole transport material were deposited on the ITO(indium thin oxide)/glass substrate by vacuum evaporation. And then, blue color emission layer was deposited using GDI602 as a host material and GDI691 as a dopant. Finally, small molecule OLEDs with structure of ITO/2-TNATA/NPB/GDI602:GDI691/Alq3/LiF/Al were obtained by in-situ deposition of Alq3, LiF and Al as the electron transport material, electron injection material and cathode, respectively. Blue OLEDs fabricated in our experiments showed the color coordinate of CIE(0.14, 0.16) and the maximum power efficiency of 1.1 lm/W at 11 V with the peak emission wavelength of 464 nm.

Red Emission Properties of Organic EL Having Hole Blocking Layer (정공블록킹층을 설치한 유기 EL의 적색발광특성)

  • Kim, Hyeong-Gweon;Lee, Eun-Hak
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.37 no.6
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    • pp.17-23
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    • 2000
  • In this study, we prepared red organic light-emitting-diode(OLED) with a fluorescent dye(Sq)-doped and inserted between emission and cathode layer 1,3-bis(5-p-t-butylphenyl)-1,3,4-oxadiazol-2-yl)benzene (OXD7) or/and tris(8-hydroxyquinoline) aluminum ($Alq_3$) layers for increasing electroluminescent(EL) efficiency. This inserting effect has been observed and EL mechanism characteristics have been examined. The hole transfer layer is a N,N'-diphenyl-N,N'-bis-(3-methyl phenyl)-1,1'-diphenyl-4,4'-diamine (TPD), and the host and guest materials of emission layer is $Alq_3$ and bis[1-methyl-3,3'-dimethyl-2-indorindiylmethyl] squaraine (Sq), respectively. For the inserting of $Alq_3$, emission efficiency increased. But we can not obtained highly pure red emission owing to the emission of inserting $Alq_3$ layer. The inserting of OXD7 makes hole block and accumulate. Because of increasing recombination probability of electron and hole, highly pure red color can be held. Simultaneously brightness characteristics and emission efficiency could improve.

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A Study of FC-NIC Design Using zynq SoC for Host Load Reduction (호스트 부하 경감 달성을 위한 zynq SoC를 적용한 FC-NIC 설계에 관한 연구)

  • Hwang, Byeung-Chang;Seo, Jung-hoon;Kim, Young-Su;Ha, Sung-woo;Kim, Jae-Young;Jang, Sun-geun
    • Journal of Advanced Navigation Technology
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    • v.19 no.5
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    • pp.423-432
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    • 2015
  • This paper shows that design, manufacture and the performance of FC-NIC (fibre channel network interface card) for network unit configuration which is based on one of the 5 main configuration items of the common functional module for IMA (integrated modular Avionics) architecture. Especially, FC-NIC uses zynq SoC (system on chip) for host load reductions. The host merely transmit FC destination address, source memory location and size information to the FC-NIC. After then the FC-NIC read the host memory via DMA (direct memory access). FC upper layer protocol and sequence process at local processor and programmable logic of FC-NIC zynq SoC. It enables to free from host load for external communication. The performance of FC-NIC shows average 5.47 us low end-to-end latency at 2.125 Gbps line speed. It represent that FC-NIC is one of good candidate network for IMA.

A Comparative Study of Machine Learning Algorithms Using LID-DS DataSet (LID-DS 데이터 세트를 사용한 기계학습 알고리즘 비교 연구)

  • Park, DaeKyeong;Ryu, KyungJoon;Shin, DongIl;Shin, DongKyoo;Park, JeongChan;Kim, JinGoog
    • KIPS Transactions on Software and Data Engineering
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    • v.10 no.3
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    • pp.91-98
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    • 2021
  • Today's information and communication technology is rapidly developing, the security of IT infrastructure is becoming more important, and at the same time, cyber attacks of various forms are becoming more advanced and sophisticated like intelligent persistent attacks (Advanced Persistent Threat). Early defense or prediction of increasingly sophisticated cyber attacks is extremely important, and in many cases, the analysis of network-based intrusion detection systems (NIDS) related data alone cannot prevent rapidly changing cyber attacks. Therefore, we are currently using data generated by intrusion detection systems to protect against cyber attacks described above through Host-based Intrusion Detection System (HIDS) data analysis. In this paper, we conducted a comparative study on machine learning algorithms using LID-DS (Leipzig Intrusion Detection-Data Set) host-based intrusion detection data including thread information, metadata, and buffer data missing from previously used data sets. The algorithms used were Decision Tree, Naive Bayes, MLP (Multi-Layer Perceptron), Logistic Regression, LSTM (Long Short-Term Memory model), and RNN (Recurrent Neural Network). Accuracy, accuracy, recall, F1-Score indicators and error rates were measured for evaluation. As a result, the LSTM algorithm had the highest accuracy.

Effect of Hole-Transporting Layer and Solvent in Solution Processed Highly-Efficient Small Molecule Organic Light-Emitting Diodes

  • Jo, Min-Jun;Hwang, Won-Tae;Chae, Hee-Yeop
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.08a
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    • pp.250-250
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    • 2012
  • Organic light-emitting diodes (OLED) and polymer light emitting diodes (PLED) have been regarded as the candidate for the next generation light source and flat panel display. Currently, the most common OLED industrial fabrication technology used in producing real products utilizes a fine shadow mask during the thermal evaporation of small molecule materials. However, due to high potential including low cost, easy process and scalability, various researches about solution process are progressed. Since polymer has some disadvantages such as short lifetime and difficulty of purifying, small molecule OLED (SMOLED) can be a good alternative. In this work, we have demonstrated high efficient solution-processed OLED with small molecule. We use CBP (4,4'-N,N'-dicarbazolebiphenyl) as a host doped with green dye (Ir(ppy)3 (fac-tris(2-phenyl pyridine) iridium)). PBD (2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole) and TPD (N,N'diphenyl-N,N'-Bis (3-methylphenyl)-[1,1-biphenyl]-4,4'-diamine) are employed as an electron transport material and a hole transport material. And TPBi (2,2',2''-(1,3,5-phenylene) tris (1-phenyl-1H-benzimidazole)) is used as an hole blocking layer for proper hole and electron balance. With adding evaporated TPBi layer, the current efficiency was very improved. Among various parameters, we observed the property of OLED device by changing the thickness of hole transporting layer and solvent which can dissolve organic material. We could make small molecule OLED device with finding proper conditions.

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Screening of Bacterial Surface Display Anchoring Motif Using Tetrameric β-galactosidase in Bacillus subtilis Spore (Tetrameric β를 이용한 고초균 포자에서의 미생물 표면 발현 모체 선별)

  • Kim, June-Hyung;Pan, Jae-Gu;Kim, Byung-Gee
    • KSBB Journal
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    • v.26 no.3
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    • pp.199-205
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    • 2011
  • Using tetrameric ${\beta}$-galactosidase as a model protein, anchoring motives were screened in Bacillus subtilis spore display system. Eleven spore coat proteins were selected considering their expression levels and the location in the spore coat layer. After chromosomal single-copy homologous integration in the amyE site of Bacillus subtilis chromosome, cotE and cotG were chosen as possible spore surface anchoring motives with their higher whole cell ${\beta}$-galactosidase activity. PAGE and Wester blot of extracted fraction of outer layer of purified spore, which express CotE-LacZ or CotG-LacZ fusion verified the existence of exact size of fusion protein and its location in outer coat layer of purified spore. ${\beta}$-galactosidase activity of spore with CotE-LacZ or CotG-LacZ fusion reached its highest value around 16~20 h of culture time in terms of whole cell and purified spore. After intensive spore purification with lysozyme treatment and renografin treatment, spore of BJH135, which expresses CotE-LacZ, retained only 1~2% of its whole cell ${\beta}$-galactosidase activity. Whereas spore of BJH136, which has cotG-lacZ cassette in the chromosome, retained 10~15% of its whole cell ${\beta}$-galactosidase activity, proving minor perturbation of CotG-LacZ, when incorporated in the spore coat layer of Bacillus subtilis compared to CotE-LacZ. Usage of Bacillus subtilis WB700, of which 7 proteases are knocked-out and thereby resulting in 99.7% decrease in protease activity of the host, did not prevent the proteolytic degradation of spore surface expressed CotG-LacZ fusion protein.

Analysis of the Characteristics of a White OLED using the Newly Synthesized Blue Emitting Material nitro-DPVT by Varying the Doping Concentrations of Fluorescent Dye and the Thickness of the NPB Layer (신규 합성한 청색발광재료 nitro-DPVT를 사용한 백색 유기발광다이오드의 형광색소 도핑농도 및 NPB 층의 두께 변화에 따른 특성 분석)

  • Jeon, Hyeon-Sung;Cho, Jae-Young;Oh, Hwan-Sool;Yoon, Seok-Beom
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.4
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    • pp.379-385
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    • 2006
  • A stacked white organic light-emitting diode (OLED) having a blue/orange emitting layer was fabricated by synthesizing nitro-DPVT, a new derivative of the blue-emitting material DPVBi on the market. The white-emission of the two-wavelength type was successfully obtained by using both nitro-DPVT for blue~emitting material, orange emission as a host material and Rubrene for orange emission as a guest material. The basic structure of the fabricated white OLED is glass/ITO/NPB$(200{\AA})$/nitro-DPVT$(100{\AA})$/nitro-DPVT:$Rubrene(100{\AA})/BCP(70{\AA})/Alq_3(150{\AA})/Al(600{\AA})$. To evaluate the. characteristics of the devices, firstly, we varied the doping concentrations of fluorescent dye Rubrene from 0.5 % to 0.8 % to 1.3 % to 1.5 % to 3.0 % by weight. A nearly pure white-emission was obtained in CIE coordinates of (0.3259, 0.3395) when the doping concentration of Rubrene was 1.3 % at an applied voltage of 18 V. Secondly, we varied the thickness of the NPB layer from $150{\AA}\;to\;200{\AA}\;to\;250{\AA}\;to\;300{\AA}$ by fixing doping with of Rubrene at 1.3 %. A nearly pure white-emission was also obtained in CIE coordinates of (0.3304, 0.3473) when the NPB layer was $250-{\AA}$ thick at an applied voltage of 16 V. The two devices started to operate at 4 V and to emit light at 4.5 V. The external quantum efficiency was above 0.4 % when almost all of the current was injected.

Effect of Changing the Thickness of Charge Control Layer on Performance of Green Phosphorescent Organic Light-Emitting Diodes (녹색 인광 유기발광다이오드에서 전하 조절층의 두께 변화가 성능에 미치는 효과에 대한 연구)

  • Lee, Dong-Hyung;Lee, Seok-Jae;Koo, Ja-Ryong;Lee, Ho-Won;Lee, Song-Eun;Yang, Hyung-Jin;Park, Jae-Hoon;Kim, Young-Kwan
    • Journal of the Korean Applied Science and Technology
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    • v.30 no.2
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    • pp.244-250
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    • 2013
  • We investigated green phosphorescent organic light-emitting diodes (PHOLEDs) with charge control layer (CCL) to produce high efficiency. The CCL and host material which was 4,4,N,N'-dicarbazolebiphenyl (CBP) of bipolar property can control the carrier movement in emitting layer (EML). The performance improvement by the insertion of CCL was realized to the well confined exciton and the reduced triplet exciton quenching effect in EML. Five types of devices (Device A, B, C, D, and E) were fabricated following the thickness of CCL within EML. The properties of device D using optimized thickness of CCL showed external quantum efficiency of 16.22% and luminous efficiency of 55.76 cd/A, respectively.