• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.156-156
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• 2000

Recently, the surface electronic states have attracted much attention since their standing wave patterns created around steps, defects, and adsorbates on noble metal surfaces such as Au(111), Ag(110), and Cu(111) were observed by scanning tunneling microscopy (STM). As a typical example, a striking circular pattern of "Quantum corral" observed by Crommie, Lutz, and Eigler, covers a number of text books of quantum mechanics, demonstrating a wavy nature of electrons. After the discoveries, similar standing waves patterns have been observed on other metal and demiconductor surfaces and even on a side polane of nano-tubes. With an expectation that the surface states could be utilized as one of ideal cases for studying two dimensionakl (sD) electronic system, various properties, such as mean free path / life time of the electronic states, have been characterized based on an analysis of standing wave patterns, . for the 2D electron system, electron density is one of the most importnat parameters which determines the properties on it. One advantage of conventional 2D electron system, such as the ones realized at AlGaAs/GaAs and SiO2/Si interfaces, is their controllability of the electrondensity. It can be changed and controlled by a factor of orders through an application of voltage on the gate electrode. On the other hand, changing the leectron density of the surface-state 2D electron system is not simple. On ewqy to change the electron density of the surface-state 2D electron system is not simple. One way to change the electron density is to deposit other elements on the system. it has been known that Pd(111) surface has unoccupied surface states whose energy level is just above Fermi level. Recently, we found that by depositing Pd on Cu(111) surface, occupied surface states of Cu(111) is lifted up, crossing at Fermi level around 2ML, and approaches to the intrinsic Pd surface states with a increase in thickness. Electron density occupied in the states is thus gradually reduced by Pd deposition. Park et al. also observed a change in Fermi wave number of the surface states of Cu(111) by deposition of Xe layer on it, which suggests another possible way of changing electron density. In this talk, after a brief review of recent progress in a study of standing weaves by STM, I will discuss about how the electron density can be changed and controlled and feasibility of using the surface states for a study of 2D electron system. One of the most important advantage of the surface-state 2D electron system is that one can directly and easily access to the system with a high spatial resolution by STM/AFM.y STM/AFM.

• Proceedings of the Materials Research Society of Korea Conference
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• 1992.05b
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• pp.26-27
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• 1992

The effect of activation and electroless nickel plating conditions on contact properties were investigated for selective electroless nickel plating of Si farers in order to obtain an optimum condition of contact hole filling. According to RCA prosess, p-type si 1 icon (100) surface was cleaned out and activated. The effects of temperture, DMAB concentration, time, and stirring iwere investigated for activation of p-type Si(100) surface. The optimal activation condition obtained was 0.5M HF, 1mM PdCl$_2$, 2mM EDTA, 7$0^{\circ}C$, 90sec under ultrasonic vibration. In electroless nickel plating, the effect of temperature, DMAB concentration, pH, and plating ti me were studied. The optimal plating condition found was 0. 10M NiS0$_4$.$H_2O$, 0.lIM Citrate, pH 6.8, 6$0^{\circ}C$, 30 minutes. The contact resistence of fi]ms wascomparatively low. It took 30 minutes to obtain 1$\mu$m thick film with 8$\mu$M DMAB concentration. The film surface roughness was improved with increasing temperature and decreasing pH of the plating solution. The best quality of the film was obtained with the condition of temperature 6$0^{\circ}C$ and pH 6.8. The micro-victors hardness of film was about 600Hv and was decreased wi th increasing particle size of plating layer.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.2
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• pp.118-123
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• 2010

The eco-friendly technologies have been extended as matter of international concern due to various diseases and syndromes according to an environmental pollution. In this study, we have manufactured a ceramic cluster with thick film type for anion generation equipment which is maximized anion but minimized ozone contents generated. To develop the formulation of ceramic cluster, we conducted the $Mg_2SiO_4$ powders doped with 10 vol% glass frits as Na-Zn-B-O system and sintered at $1050^{\circ}C$ for 2 hours in air for starting materials and investigated the matching properties between the Ag-Pd electrode and the starting materials. The sintered sample for the composition of cluster has 6.7 of dielectric constant and 32 kV/mm of withstand voltage. The yield of anions was measured according to an electrode pattering, discharge gap between electrode, and thickness of electrode protective layer in the cluster of thick film type. We have manufactured the ceramic clusters with optimized thick film structure that have an anion over a hundred particles and the ozone of 0.6 ppb generated.

• 전기의세계
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• v.42 no.4
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• pp.29-35
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• 1993

1. 현장 시험을 위하여 여러가지 방법이 제안되어 적용되고 있지만 그 어느것도 뚜렷한 결과를 제시하지 못 하고 있다. 2. DC test는 이미 언급된 문제로 인하여 시험목록에서 제외되어야 한다. 3. 교류 시험은 현재 많이 적용되고 있지만, 경우에 따라서는 적용이 불가능하다. 그러나 전력원에 직접 케이블 선로를 연결하는 것이 가능한 경우에는 1.732U$_{0}$ 전압에서의 시험은 타당하다고 할 수 있다(시험 시간이 명기되어야 함). 4. 진동파 시험은 충분히 민감하지 않지만, U$_{0}$하에서 PD측정을 병행하면 타당한 방법이 될 수 있다. 5. HV 케이블에 있어서 다른 방법(VLF와 SI)의 적용은 더 구체적으로 연구되어야 한다.

• Proceedings of the Korean Magnestics Society Conference
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• 2012.11a
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• pp.59-60
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• 2012

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.11a
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• pp.425-426
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• 2002

VOCs 처리 기술로서 촉매연소의 경우 저온에서 처리가 가능하여 처리비용 절감 등의 효과를 고려할 때 가장 경제적인 방법으로 평가되고 있다. 촉매연소를 이용한 VOCs 처리는 고가의 귀금속(Pt, Pd 등)을 담지한 담체(carbon black, SiO$_2$, $Al_2$O$_3$, TiO$_2$ 등)형 촉매가 사용되고 있다(Guisnet, et al, 1999). (중략)

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.7
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• pp.3151-3156
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• 2014

Background: Sorafenib is a promising drug for advanced hepatocellular carcinoma (HCC); however, treatment may be discontinued for multiple reasons, such as progressive disease, adverse events, or the cost of treatment. The consequences of sorafenib discontinuation and continuation are uncertain. Materials and Methods: We retrospectively analyzed 88 HCC patients treated with sorafenib from July 2007 to January 2013. Overall survival (OS), post-disease progression overall survival (pOS), and time to disease progression (TTP) were compared for survival analysis. Cox proportional hazard regression was performed to assess the effect of important factors on OS in the overall patient population and on pOS in patients who continued sorafenib treatment. Results: Sorafenib was discontinued and continued in 24 and 64 patients, respectively. The median OS (355 vs 517 days respectively; p=0.015) and median post-PD OS (260 vs 317 days, respectively; p=0.020) were statistically different between the discontinuation and continuation groups. Neither the median time to first PD nor the time to second PD were significantly different between the 2 groups. In the discontinuation group, 3 of the 24 patients (12.5%) suffered disease outbreaks. In Cox proportional hazard regression analysis after correction for confounding factors, BCLC stage (p=0.002) and PD site (p=0.024) were significantly correlated with pOS in patients who continued sorafenib treatment. Conclusions: Sorafenib discontinuation may cause HCC flares or outbreaks. It is advisable to continue sorafenib treatment after first PD, particularly in patients with Barcelona Clinic Liver Cancer stage B disease or only intrahepatic PD.

• Korean Journal of Materials Research
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• v.6 no.10
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• pp.1017-1024
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• 1996

본 연구에서는 여러 기판에 대한 Cu의 확산정도를 알기 위하여 Ta, Nb, Co/Ta이중층 및 Co/Nb 이중층 위에 기화법으로 증착하고 열처리를 실시하였다. 열처리한 Ta막은 열처리하지 않은 Ta막보다 Cu 확산방지막으로서의 성능이 더 떨어지는데, 이것은 열처리에 의하여 Ta막이 결정화되기 때문이다. Cu/Co/Ta/(001)Si 구조에서의 구리 실리사이드 생성온도는 Cu/Co/Ta(001)Si 구조에서의 그것보다 더 높다. 한편, nb의 Cu에 대한 barrier 특성은 Ta와 비슷한 수준이다. 또한 Cu막 도포 이전에 Pd+HF활성화 전처리나 N2플라즈마 전처리를 실시하면, Cu의 핵생성뿐만 아니라 기판에 대한 Cu막의 접착성도 향상된다.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1996.06a
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• pp.399-421
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• 1996

(1) The solute distribution mechanism was analyzed for the Si0.95Ge0.05 single crystal fiber by u-PD method. (2) The steady-state solutions were obtained for the molten zone and the capillary zone. (3) The effect of the convection in the molten zone on partitioning was not significant for many cases. (4) Intermediate transient rise of Ge was shown by the sudden change of the growth velocity or molten zone height. (5) Periodic compositional modulation can be designed by using the intermediate transient.

• Journal of the Korean institute of surface engineering
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• v.24 no.1
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• pp.25-30
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• 1991

The evaporation characteristics of Ag, Al, Au, Cr. Cu, In, Mg, Mn, Pb, Pd, Si, SiO, Sn, Ti and Zn with the various resistive heating sources have been studied. The employed sources are refractory metal (Mo, Ta and W) boats, W-wire, ceramic (usually Al2O3)-coated and -barriered refractory metal boats, and special boats such as baffled boats and intermetallic boats (nitride compound and graphite). We investigated the melting mode, evaporation rate at a specific power, and lifetime of the sources. A special boat holder is also discussed which is needed to cool the sources at a large heat capacity.