• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.357-358
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• 2013

The non-linear characteristics of ON states are important for the application to the high density cross-point memory industry because the sneak current in neighbor cells occurred during reading, erasing, and writing process. Kw of above 20 in ON states, which is the writing current @ Vwrite/the current @ 1/2Vwrite, was required in cross-point ReRAM memory industry. The high current density non-linear IV curve of ZnSe selector was shown and the ALD HfO2 switching device has the linear properties of ON states and the compliance current of 100 uA. To evaluate the performance of the selection device, we connected itto HfO2 switching device in series. The bottom electrode of the selection device was connected to the top electrode of the RRAM. All of the bias was applied with respect to the top electrode of the selection device, whereas the bottom electrode of the RRAM was grounded. In the cross-point application, 1/2Vwrite and -1/2Vwrite were applied to the word-line and bit-line, respectively, which were connected to the selected cell, and a zero bias was applied to the unselected word-lines and bit-lines. The current @ 1/2Vwrite of the unselected cells was blocked by the selection device, thus eliminating the sneak path and obtaining a writing voltage margin. Using this method, the writing voltage margin was analyzed on the basis of the memory size.

• 한국식품저장유통학회지
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• 제21권1호
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• pp.17-24
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• 2014

신선편이 단호박 원료의 수확 후 적정 후숙 기간과 신선편이 가공 후 포장방법을 구명하고자 연구를 수행하였다. 소형 단호박 '보짱'을 수확하여 1주, 2주 후숙시킨 다음 1차 수돗물 세척 후 $100{\mu}L/L$의 염소수에 살균소독 세척한 다음 절단하여 $80{\mu}m$ PE/Ny 필름에 진공 및 밀봉포장 하여 $5^{\circ}C$에서 21일간 저장하였다. 단호박의 후숙기간은 신선편이 가공 후 포장내부의 기체 조성 및 품질에 영향을 미쳤다. 단호박 원료 2주 후숙 처리는 1주 후숙 처리보다 신선편이 제품 저장 중 $CO_2$ 농도가 2.2~5.0 kPa 낮았고, 저장 7일이후 경도가 낮게 나타났으며, 당도는 2주 후숙이 1주 후숙처리 보다 2~3% 높게 나타났다. 그리고 적색도(Hunter a)도 2주 후숙이 1주 후숙보다 높게 나타났고, 색과 외관에 대한 관능점수가 높아 기호성이 우수하였으며, 이취발생도 적어 저장 3주까지 상품성을 유지하였다. 그리고 밀봉포장은 진공포장보다 미생물 수가 적고, 외관에 대한 관능적 점수가 높게 나타났다. 따라서 단호박을 수확 후 2주 후숙한 다음 신선편이 가공하여 밀봉포장하는 것이 신선편이 단호박의 품질을 높일 수 있는 방법으로 판단되었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.432.2-432.2
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• 2016

A new A-D-A type (Acceptor-Donor-Acceptor) conjugated based on pyridine-borane complex (Donor), non-boron fluorine (Donor) and 2,5-bis(alkyl)-3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (DPP) (Acceptor) were designed and synthesized via Pd-catalyzed Suzuki cross-coupling reaction. The synthesized boron based complex exhibited high electron affinity, which indicates deep HOMO energy levels and good visible absorption led to their use as donors in BHJ (bulk heterojunction) solar cells. Inverted devices were fabricated, reaching open-circuit voltage as high as 0.91eV. To probe structure-property relationship and search for design principle, we have synthesized pyridine-boron based electron donating small molecules. In this study, we report a new synthetic approach, molecular structure, charge carrier mobility and morphology of blended film and their correlation with the photovoltaic J-V characteristics in details.

• 한국지반공학회지:지반
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• 제13권3호
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• pp.5-20
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• 1997

본 연구에서는 유한변형률 이론에 근거하여 3차원 압밀 지배 방정식을 유도하였다. 이 방정식은 비교적 압밀층의 두께가 두꺼운 경우, 비선형 물성치, 공극비에 따른 비선형 투수계수를 갖는 지반에 적합하다. 기존의 유한차분 수치해석 기법(FTCS)은 지배 방정식이 비선형 이며 복잡한 경우 안정된 해를 얻을 수 없기 때문에 본 연구에서는 특수 유한 차분 기법을 도입하였다. 이 수치해석 기법을 지배 방정식에 적용하면 시간에 따른 압밀량을 예측할 수 있다. 본 해석기법에 의해 구해진 값들을 윅드레인을 설치한 여러 가지 고압축성 토질에서의 실험 결과와 비교한 결과, 최종 압밀량과 시간에 따른 압말량이 잘 일치하고 있다.

• 한국진공학회지
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• 제6권S1호
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• pp.110-114
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• 1997

Development of metal ion source growth of high quality Cu metal film formation of non-stoichiometric $SnO_2$ films of Si(100), and modification fo polymer surface by low enregy ion beam have been carried out at KIST Ion Beam Lab. A new metal ion source with high ion beam flux has been developed by a hybrid ion beam (HIB) deposition and non-stoichiometric $SnO_2$ films are controlled by supplying energy. The ion assisted reaction (IAR) in which keV ion beam is irradiated in reactive gas environment has been deveolped for modifying the polymers and enhancing adhesion to other materials and advantages of the IAR have been reviewed.

• 한국진공학회지
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• 제16권1호
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• pp.65-73
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• 2007

마이크로유체 채널 내에서 표면 성질과 기능성 분자들의 공간적인 위치를 제어하는 것은 진단소자, 마이크로 반응기, 또는 세포와 마이크로 유체역학의 기본적인 연구를 일해 매우 중요하다. 이 논문에서는 소프트 리소그라피 방법을 이용하여 채널 안에 패턴된 구조물을 포함하는 안정적인 마이크로 채널을 제작하는 방법을 소개하려 한다. 먼저 패턴된 영역을 폴리디메틸실록세인(PDMS) 몰드의 치수와 제작 과정을 적당히 조절함으로써 산소 플라즈마로부터 보호한다. 마이크로 구조물은 대표적인 생물오손(biofouling) 억제 물질인 폴리에틸렌 글리콜(PEG)계 공중합 고분자 혹은 다당류인 히알루산(HA)을 패턴하여 얻었으며 이러한 패턴을 이용하여 피브로넥틴(FN), 소의 혈장 알부민(BSA) 등의 단백질과 동물 세포의 어레이를 제작하였다.

• KIEAE Journal
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• 제16권1호
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• pp.5-10
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• 2016

Purpose: The energy consumption in buildings has continuously increased in some countries and it reaches almost 25% of the total energy use in korea. Therefore there are various efforts to minimize energy consumption in buildings, and the regulations on building envelope insulation have been tightened up gradually. To satisfy the building regulation, the use of vacuum insulation panels(VIPs) is increasing. VIP is a high performance insulation materials, so that it can be thinner than conventional insulation material. When VIP is applied in a building, it may cause thermal bridge, which occurs due to very low thermal conductivity compared to other building materials and the envelope of VIPs. Method: This study designed the capsulized VIPs using conventional insulation for reduction of the thermal bridge. Then designed VIPs were applied to a wall. The linear thermal transmittance and the effective thermal conductivity were analyzed by HEAT2 simulation program for two dimensional steady-state heat transfer. The result compared with a wall with non-capsulized VIPs. Result: It analyzed that the wall with capsulized VIPs had lower linear thermal transmittance and reduced the difference of the effective thermal transmittance with one dimensional thermal transmittance compared to that of the wall with non-capsulized VIPs.

• 센서학회지
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• 제24권4호
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• pp.215-218
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• 2015

As several innovative technologies for flexible electric devices are being realized, demand for in-situ strain monitoring for flexible electric devices is being emphasized. Because flexible devices are commonly influenced by substrate strain, suitable strain sensors for flexible devices are essential for the sophisticated maneuvering of flexible devices. In this study, a flexible strain sensor based on an Ag electrode is prepared on a polyimide substrate using the LDW (laser direct writing) process. In this process, first, the Ag nanoparticles are coated on the substrate and selectively sintered using a focused laser. Because of the advantages of the LDW process (such as being mask-less, using low temperatures, and having non-vacuum characteristics), the entire fabrication process has been dramatically simplified; as a final outcome, a highly reliable strain sensor has been fabricated. Using this strain sensor, various strain conditions that arise from different bending radii can be detected by measuring real-time electrical signals.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.236.1-236.1
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• 2014

Compounds of Ga, such as gallium oxide (Ga2O3) and gallium nitride (GaN), are of interest due to its unique properties in semiconductor application. In particular, GaN has the potentially application for optoelectronic device such as light-emitting diodes (LEDs) and laser diodes (LDs) [1]. Nanoparticle is an interesting material due to its unique properties compared to the bulk equivalents. In this report, we develop a synthesizing method for gallium nitride nanoparticle using non-thermal plasma. For gallium source, the gallium is heated by thermal conduction of tungsten boat which is heated by eddy current induced from RF current in antenna. Nitrogen source for nanoparticle synthesis are from inductively coupled plasma with N2 gas. The synthesized nano particles are analyzed using field-emission scanning microscope (FESEM), transmission electron microscope (TEM) and x-ray photoelectron spectroscopy (XPS). The synthesized particles are investigated and discussed in wide range of experiment conditions such as flow rate, pressure and RF power.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.189.1-189.1
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• 2014

Lead zirconium titanate (PZT) is usually used as bulk and thin films. Due to high flexibility and piezoelectric, ferroelectric and pyroelectric properties, PZT fiber has attracted in a variety of fields such as sensor devices, non-electromechanical systems and non-volatile ferroelectric memory devices. And PZT fiber can be numerously synthesized and almost with the diameter of PZT fiber thicker than $10{\mu}m$. However, the electrospinnig method is cost effective and convenient. PZT obtained by electrospinning methodhas the diameter from sub-micro to nanometer. In this paper, the PZT/PVP nanofibers were synthesized with three precursors, lead nitrate, zirconium ethoxide and titanium isopropoxide. And the PZT nanofibers were fabricated after removal of PVP by annealing process at various temperature. The obtained PZT nanofibers were characterized by means of X-ray photoelectron spectroscopy (XPS) for chemical properties, X-ray diffraction (XRD) for crystallinity and phase, scanning electron microscopy (SEM) for morphologies. The diameter of PZT nanofibers were measured with SEM. From the SEM images, we confirmed that diameter of PZT nanofibers was hundreds of nanometers and decreased with increasing the annealing temperature. When the annealing temperature increased, the crystallinity of PZT nanofibers changed from pyrochlore to perovskite structure.