• JSTS:Journal of Semiconductor Technology and Science
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• 제14권5호
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• pp.615-624
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• 2014

In this paper, we explore the electrical properties and high-frequency performance of carbon nanotube field-effect transistors (CNTFETs), based on the non-equilibrium Green's functions (NEGF) solved self - consistently with Poisson's equations. The calculated results show that CNTFETs exhibit superior performance compared with graphene nanoribbon field-effect transistors (GNRFETs), such as better control ability of the gate on the channel, higher drive current with lower subthreshold leakage current, and lower subthreshold-swing (SS). Due to larger band-structure-limited velocity in CNTFETs, ballistic CNTFETs present better high-frequency performance limit than that of Si MOSFETs. The parameter effects of CNTFETs are also investigated. In addition, to enhance the immunity against short - channel effects (SCE), hetero - material - gate CNTFETs (HMG-CNTFETs) have been proposed, and we present a detailed numerical simulation to analyze the performances of scaling down, and conclude that HMG-CNTFETs can meet the ITRS'10 requirements better than CNTs.

• International Journal of Industrial Entomology and Biomaterials
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• 제8권1호
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• pp.113-115
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• 2004

Six generations (P$_1$, P$_2$, F$_1$, BC$_1$, BC$_2$ and F$_2$) of four bivoltine silkworm crosses (SKAU-R-1 ${\times}$ Yakwei, SKAU-R-6 ${\times}$ Yakwei, CSR$_2$ ${\times}$ CSR$_4$ and SH$_{6}$${\times}$ NB$_4$D$_2$) were evaluated in a completely randomized block design with 5 replications for each treatment. The generation mean 2 in respect of 3 metric traits (single cocoon weight, single shell weight, and shell ratio ％), were subjected to Cavallis joint scaling test. Additive dominance model was found to be adequate in CSR$_2$${\times}$CSR$_4$ and SH$_{6}$${\times}$ NB$_4$D$_2$ for single cocoon weight and shell weight and SKAU-R-6 ${\times}$ Yakwei for shell ratio(％). Whereas, in rest of the crosses epistasis was evident in the traits under investigation. Magnitude of additive gene effect (d) was greater than dominance(h) in SH$_{6}$${\times}$NB$_4$D$_2$ and SKUA-R-6${\times}$Yakwei for shell ratio (％) and in CSR$_2$${\times}$ CSR$_4$ for shell weight. Thus selection for these traits in early segregating generations of these crosses would be effective for obtaining considerable genetic gain. gain.

• 대한치과의사협회지
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• 제54권6호
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• pp.429-437
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• 2016

Objectives: Photodynamic therapy has been proven to promote additional clinical and microbiological benefits in the treatment of chronic periodontitis and aggressive periodontitis. The purpose of this study is to assess the effectiveness of the photodynamic therapy for patient with periodontitis. Methods: We searched the eight Korean databases and Ovid-MEDLINE, Ovid-EMBASE, Cochrane Library. Total 300 studies were searched and 13 studies were included in the final assessment. Each of the stages from literature search and extraction of data were carried out independently by 2 researchers. We used tools of Scottish Intercollegiate Guidelines Networks for assessment of the quality of studies. Results: The safety of the photodynamic therapy was assessed by bleeding. The effectiveness of the photodynamic therapy was assessed by the reduction of Probing pocket depth (PPD) and the gain of Clinical attachment level (CAL). The mean difference of PPD was 0.46(95% CI 0.09~0.82), (p=.01).). The mean difference of CAL was ?0.49(95% CI ?1.12~0.14), (p=.13). Conclusion: The additional use of $^{\circ}{\infty}$Antimicrobial Photodynamic Therapy for Periodontitis$^{\circ}{\pm}$ caused hemorrhage to similar extents to conventional treatment modalities, where scaling and root planing are solely performed, in patients with periodontitis who are expected to have a lower degree of treatment response to non-surgical or surgical periodontal therapies (implant or refractory periodontitis) and those where there is a concern for the possible occurrence of antimicrobial side effects or resistance. This indicates that there are no problems with its safety. But there were no consistent reports about the effects of the additional use of photodynamic therapy. This led to a decision that the safety and efficacy of the current technology deserve further studies (Recommendation rating of A, Classification of technology II-a).

• 대한전자공학회논문지SD
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• 제43권4호
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• pp.23-30
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• 2006

본 연구에서는 나노 스케일 MuGFET(Mutiple-Gate FETs)의 단채널 효과와 corner effect를 3차원 시뮬레이션을 통하여 분석하였다. 문턱전압 모델을 이용하여 게이트 숫자(Double-gate=2, Tri-gate=3, Pi-gate=3.14, Omega-gate=3.4, GAA=4)를 구하였으며 추출된 게이트 숫자를 이용하여 각각의 소자 구조에 맞는 natural length($\lambda$)값을 얻을 수 있었다. Natural length를 통하여 MuGFET의 단채널 효과를 피할 수 있는 최적의 소자 구조(실리콘 두께, 게이트 산화막의 두께 등)를 제시 하였다. 이러한 corner effect를 억제하기 위해서는 채널 불순물의 농도를 낮게 하고, 게이트 산화막의 두께를 얇게 하며, 코너 부분을 약 17%이상 라운딩을 해야 한다는 것을 알 수 있었다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.666-669
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• 2008

Droplet in miniaturized microfluidic systems have received much focused attention recently. In this work, electrical charging phenomenon of a conducting water droplet on the electrode under the dc electric field is studied and using this phenomenon droplet actuation method for microreactor applications is experimentally demonstrated. To find effects of key factors, the effects of electric field, medium viscosity, and droplet size are investigated. A scaling law of charging for the conducting droplet is derived from the experimental results. Unlike the case of a perfect conductor, the estimated amount of electrical charge ($Q_{est}$) of a water droplet is proportional to the 1.59 power of the droplet radius (R) and the 1.33 power of the electric field strength (E). (For a spherical perfect conductor, Q is proportional to R2 and E.) It is thought that the differences are mainly due to incomplete charging of a water droplet resulted from the combined effect of electrochemical reaction at electrode and the relatively low conductivity of water. Using this phenomenon, we demonstrate the transport of the charged droplet and fusion of two oppositely-charged droplets. When electric field is subjected sequentially on the electrode, the charged droplet is transported on the electrode. For the visualization of fusion of charged droplets, the precipitation reaction is used. When subjected to a DC voltage, two droplets charged are moving and merging toward each other due to the Coulombic force and chemical reaction is simultaneously occurred by coalescence of droplets. It may be due to the interchange effect of charge. It is shown that the droplet can be used for microreactor where transporting, merging etc. of reagents constitute unit operation.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.178-178
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• 2010

With the scaling down of ULSI(Ultra Large Scale Integration) circuit of CMOS(Complementary Metal Oxide Semiconductor)based electronic devices, the electronic devices become more faster and smaller size that are promising field of semiconductor market. However, very narrow line width has some disadvantages. For example, because of narrow line width, deposition of conformal and thin barrier is difficult. Besides, proportion of barrier width is large, thus resistance is high. Conventional PVD(Physical Vapor Deposition) thin films are not able to gain a good quality and conformal layer. Hence, in order to get over these side effects, deposition of thin layer used of ALD(Atomic Layer Deposition) is important factor. Furthermore, it is essential that copper atomic diffusion into dielectric layer such as silicon oxide and hafnium oxide. If copper line is not surrounded by diffusion barrier, it cause the leakage current and devices degradation. There are some possible methods for improving the these secondary effects. In this study, TaNx, is used of Tertiarybutylimido tris (ethylamethlamino) tantalum (TBITEMAT), was deposited on the 24nm sized trench silicon oxide/silicon bi-layer substrate with good step coverage and high quality film using plasma enhanced atomic layer deposition (PEALD). And then copper was deposited on TaNx barrier using same deposition method. The thickness of TaNx was 4~5 nm. TaNx film was deposited the condition of under $300^{\circ}C$ and copper deposition temperature was under $120^{\circ}C$, and feeding time of TaNx and copper were 5 seconds and 5 seconds, relatively. Purge time of TaNx and copper films were 10 seconds and 6 seconds, relatively. XRD, TEM, AFM, I-V measurement(for testing leakage current and stability) were used to analyze this work. With this work, thin barrier layer(4~5nm) with deposited PEALD has good step coverage and good thermal stability. So the barrier properties of PEALD TaNx film are desirable for copper interconnection.

• 한국환경농학회지
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• 제31권1호
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• pp.24-29
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• 2012

BACKGROUND: In recent years, microbial fuel cells (MFCs) have emerged as a promising technology for recovering renewable energy from waste biomass, especially wastewater. In this study, the possibility of bioelectricity generation in two chambered mediator-less microbial fuel cells (MFCs) was successfully demonstrated using fermentable and non-fermentable substrates. METHODS AND RESULTS: Two different electron acceptors have been tested in the cathode chamber for the effects of reducing agent on the power generation in MFCs. The average voltages of $0.26{\pm}0.014$ V and $0.36{\pm}0.02$ V were achieved with acetate using oxygen and potassium ferricyanide as reducing agent, respectively. Similarly, with glucose the average voltages of $0.256{\pm}0.05$ V and $0.340{\pm}0.04$ V were obtained using oxygen and ferricyanide, respectively. Using potassium ferricyanide as the reducing agent, the power output increases by 39 and 43% with acetate and glucose, respectively, as compared to the dissolved oxygen. Slightly higher coulombic efficiency (CE%) was obtained in acetate as compared to MFCs operated with glucose. The maximum power densities of 124 mW/$m^2$ and 204 mW/$m^2$ were obtained using dissolved oxygen and $K_3Fe(CN)_6$, respectively. CONCLUSION(s): This study demonstrates that power generation from the MFCs can be influenced significantly by the different types of catholyte. Relatively higher CE was obtained with $K_3Fe(CN)_6$. Thus, application of $K_3Fe(CN)_6$ as the catholyte can be vital for scaling uppower generation from the MFCs forreal time applications.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제32권2호
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• pp.168-173
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• 2006

The side effects of head and neck radiation therapy include mucositis, xerostomia, loss of taste, radiation caries, oral infection, osteoradionecrosis and trismus. When a patient is arranged to begin head & neck radiotherapy, oral pathologic lesions are examined and managed for the prevention of oral complications. The advanced odontogenic infection should be especially controlled before the radiotherapy and the patient must be instructed for proper oral prophylaxis. Generally the more conservative treatments, such as, scaling, restoration, endodontic treatment, are the care of choice and dental extraction is performed in advanced periapical and periodontal pathologic conditions. If the dental extraction should be done, the radiotherapy consequently will be delayed until there is epithelium covering the extraction socket, leaving no exposed bone. The cancer patient with severe emotional stress pray for the early radiation therapy, in spite of possibility of the recurrent odontogenic infectious lesions. So, the authors attempted to do the early radiation therapy by the conservative endodontic drainage and surgical incision & drainage without extraction of the infected teeth, and resulted in relatively good prognosis without the severe side effects of head and neck radiotherapy.

• 디지털융복합연구
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• 제14권12호
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• pp.537-544
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• 2016

본 연구의 목적은 기초 수급자들을 대상으로 실시하고 있는 노인들의 불소도포 및 스켈링 사업을 통하여 그들의 구강건강 상태와 구강건강 관련 행태를 살펴보고 잔존 치아 수와의 관련성에 대하여 조사하고자 한다. 65세이상 기초 수급자 노인 660명을 대상으로 자기기입식 설문조사를 시행하였고, 구강검진을 통하여 틀니사용 유무와 잔존 치아 수 등을 조사하였다. 연령이 증가함에 따라 잔존 치아 수는 줄어들었으며, 성별, 연령, 구강위생용품의 사용, 자가 구강상태 진단, 점심 식사 후 칫솔질 유무에 따라서 잔존 치아 수에 차이가 나타났고 통계적으로도 유의하였다(p<0.05). 잔존 치아 수는 대상자 개인의 구강 예방에 대한 관심과 노력으로 예방이 가능하다. 따라서 노인들의 구강건강 행태가 잔존 치아 수에 미치는 융복합적 용인을 샆펴보고, 취약계층에 대한 예방 진료의 확대와 보건관리의 제공을 유지하기 위한 구강관리 프로그램이 지속적으로 제공되었으면 한다.

• Journal of Periodontal and Implant Science
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• 제36권1호
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• pp.69-84
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• 2006

Reports on the comparison of clinical effect between non-surgical and surgical therapy, and the change of the clinical parameters during maintenance phase have been rarely presented in Korea. This study was to observe the clinical changes during maintenance phase of 6 months in patients with chronic periodontitis treated by non-surgical or surgical therapy in Department of Periodontics, Chonnam National University Hospital. Among the systemically healthy and non-smoking patients with moderate to severe chronic periodontitis, twenty eight patients (mean age: 47.5 years) treated by non-surgical therapy (scaling and root planning) and nineteen patients (mean age: 47.3 years) treated by surgical therapy (flap surgery) were included in this study. The periodontal supportive therapy including recall check and oral hygiene reinforcement was started as maintenance phase since 1 month of healing after treatment. Probing depth, gingival recession. clinical attachment level and tooth mobility were recorded at initial, baseline and 1, 2, 3 and 6 month of maintenance phase. The clinical parameters were compared between the non-surgical and surgical therapies using Student t-test and repeated measure ANOVA by initial probing depth and surfaces. Surgical therapy resulted in greater change in clinical parameters than non-surgical therapy. During the maintenance phase of 6 months, the clinical effects after treatment had been changed in different pattern according to initial probing depth and tooth surface. During maintenance phase, probing depth increased more and gingival recession increased less after surgical therapy, compared to non-surgical therapy. The sites of initial probing depth less than 3 mm lost more clinical attachment level, and the sites of initial probing depth more than 7 mm gained clinical attachment level during maintenance phase after non-surgical therapy, compared to surgical therapy. Non-surgical therapy resulted in greater reduction of tooth mobility than surgical therapy during maintenance phase. These results indicate that the clinical effects of non-surgical or surgical therapy may be different and may change during the maintenance phase.