• E2M - 전기 전자와 첨단 소재
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• 제7권2호
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• pp.117-122
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• 1994

The role of ZnS buffer layer not only suppresses chemical reactions between emission material and insulating material but also alters the luminescence and the crystallinity of the emission layer, if ZnS buffer layer was sandwiched between emission layer and insulating layer of electroluminescent device. In this research, we fabricated ZnS thin film with rf magnetron sputter system by varying rf power 100, 200W, substrate temperature 100, 150, 200, 250.deg. C and post-annealing temperature 200, 300, 400, 500.deg. C and analysed X-ray diffraction pattern, transmission spectra and cross section by SEM photograph for seeking the optimal crystallization condition of ZnS buffer layer. As a result, increasing the rf power, the crystallinity of ZnS thin film was improved. It was found that the ZnS thin film had better properties than anything else when fabricated with the following conditions ; rf power 200W, substrate temperature 150.deg. C, and post-annealing temperature 400.deg. C. ZnS thin film had the transmittance more than 80% in visible range. So it is suitable to use as a buffer layer of electroluminescent devices.

• 한국식품영양과학회지
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• 제17권4호
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• pp.358-364
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• 1988

pH조정제 sodium malate buffer(SMB)가 김치의 숙성에 미치는 영향을 검토하기 이하여 소금농도별 ($0{\sim}6%$) 및 SMB첨가농도별($1{\sim}2%$)로 김치를 담그고 숙성중 질적변화를 조사하였다. 그결과 소금농도가 증가함에 따라 김치의 숙성이 지연되었고 SMB를 첨가한 경우 및 그 첨가농도가 높은 경우가 더욱더 숙성이 지연되었다. 산도는 SMB형 가구가 오히려 높았으나 관능검사결과 산도와 반비례하여 SMB 첨가에 의한 완충능에 기인된 것으로 판단되었으며 김치의 숙성이 진행됨에 따라 완충능은 더욱 증가하였다. 소금 2% 첨가김치에 SMB의 1%첨가한 경우 2% 소금만을 첨가한 경우에 비해 $25^{\circ}C$에서 약 36시간 숙성이 지연되었으며 소금 농도가 비교적 높은 4% 첨가 김치보다는 약 12시간 숙성이 지연되었다.

• 한국초전도ㆍ저온공학회논문지
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• 제16권2호
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• pp.20-23
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• 2014

We have grown $MgB_2$ on SiC buffer layer by using metallic Hastelloy tape as the substrate. Hastelloy tape was chosen for its potential practical applications, mainly in the power cable industry. SiC buffer layers were deposited on Hastelloy tapes at 400, 500, and $600^{\circ}C$ by using a pulsed laser deposition method, and then by using a hybrid physical-chemical vapor deposition technique, $MgB_2$ films were grown on the three different SiC buffer layers. An enhancement of critical current density values were noticed in the $MgB_2$ films on SiC/Hastelloy deposited at 500 and $600^{\circ}C$. From the surface analysis, smaller and denser grains of $MgB_2$ tapes are likely to cause this enhancement. This result infers that the addition of SiC buffer layers may contribute to the improvement of superconducting properties of $MgB_2$ tapes.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.394-396
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• 2012

Chemical bath deposition (CBD) process conditions for depositing CdS buffer layers was studied for high efficiencies of CIGS thin film solar cells. Growth rate of CdS thin films has an effect on surface morphology and quality of thin films. By the change of growth rate, CdS buffer layers showed a large difference in surface morphology and this difference was closely related with the photovoltaic properties of CIGS solar cells.

• 한국환경보건학회지
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• 제30권2호
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• pp.79-83
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• 2004

The oxidative degradation of BPA with laccase from Trametes versiclor was conducted in a closed, temperature controlled system containing acetate buffer for pH control. The effects of medium pH, buffer concentration, temperature and mediator on degradation of BPA were investigated. The inactivation of the enzyme by temperature and reaction product was also studied. The optimal pH for BPA degradation showed about 5. Buffer concentration did not affect BPA degradation. On the other hand, the enzyme stability was higher at low concentration buffer(25 mM). Temperature rise increased the degradation rate of BPA up to 45$^{\circ}C$. The valuable mediator of laccase for BPA was ABTS. Elevated temperature and reaction product irreversibly inactivated the enzyme.

• 한국결정학회지
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• 제9권2호
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• pp.131-137
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• 1998

결정결함의 밀도가 낮은 GaN epitaxy 막을 MOCVD(metal organic chemical vapour deposition) 방법에 의해 성장시켰다. 기판은 6H-SiC를 사용하였으며, AlN과 GaN으로 구성된 이중 buffer 층을 도입하였다. GaN buffer 층은 반응원료인 trimethyl gallium(TMG)과 NH3 가스를 교호식펄스공급(alternating pulsative supply, APS)방법에 의해 만들었다. AlN buffer/6H-SiC 위에 초기단계에 형성되는 GaN 섬은 APS처리에 의해 크기가 커지는 것을 AFM(atomic force microscope)으로 관찰하였다. Buffer 층의 역할은 그 위에 성막시킨 GaN epitaxy 막의 결정성과 결함밀도에 의해 조사하였다. 성막된 GaN의 결정구조와 결정성은 DCXRD(double crystal X-ray diffractormeter)에 의해 측정되었다. 결정결함은 EPD(etching pit density)를 측정하는 방법으로 알칼리혼합용에서 처리된 막을 SEM(scanning electron microscope)으로 관찰하였다.

• 한국초전도ㆍ저온공학회논문지
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• 제8권4호
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• pp.19-21
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• 2006

Biaxially textured Ni was fabricated by electrodeposition process and delaminated from the biaxially textured cathode surface for further buffer layer deposition process. Those electrode posited Ni substrates showed well-developed biaxial texture and smooth surface. In order to improve the thermal stability of Ni substrates, Mn was alloyed by adding Mn precursor into the electrodeposition bath. Subsequently, $CeO_2$ buffer layers are deposited by MOD process to prevent interfacial reaction between superconductor and substrates. In particular, Bismuth oxide was added to $CeO_2$ to realize lower temperature processing of buffer layers. The microstructure and texture development of each layers have been investigated. Preliminary results shows that all electro/chemical process can be a candidate for cost effective route to YBCO coated conductor.

• 한국전기전자재료학회논문지
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• 제30권10호
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• pp.625-630
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• 2017

ZnS was chemically deposited as a buffer layer alternative to CdS, for use as a Cd-free buffer layer in $Cu(In_{1-x}Ga_x)Se_2$ (CIGS) solar cells. The deposition of a thin film of ZnS was carried out by chemical bath deposition, following which the structural and optical properties of the ZnS layer were studied. For the experiments, zinc sulfate hepta-hydrate ($ZnSO_4{\cdot}7H_2O$), thiourea ($SC(NH_2)_2$), and ammonia ($NH_4OH$) were used as the reacting agents. The mole concentrations of $ZnSO_4$ and $SC(NH_2)_2$ were fixed at 0.03 M and 0.8 M, respectively, while that of ammonia, which acts as a complexing agent, was varied from 0.3 M to 3.5 M. By varying the mole concentration of ammonia, optimal values for parameters like optical transmission, deposition rate, and surface morphology were determined. For the fixed mole concentrations of $0.03M\;ZnSO_4{\cdot}7H_2O$ and $0.8M\;SC(NH_2)_2$, it was established that 3.0 M of ammonia could provide optimal values of the deposition rate (5.5 nm/min), average optical transmittance (81%), and energy band gap (3.81 eV), rendering the chemically deposited ZnS suitable for use as a Cd-free buffer layer in CIGS solar cells.

• 대한화학회지
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• 제42권4호
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• pp.432-442
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• 1998

$pH=-loga_H$ 정의에서 pH는 단일 이온의 활동도항을 포함하므로 단지 측정의 방법만으로는 결정되어질 수 없고 근사법을 필요로 한다. 근사법에 의한 pH 측정은 수소전극과 은/염화은 전극을 사용한 액간 접촉이 없는 cell의 기전력 측정으로부터 이루어지는 방법이며, 이 과정을 통해 pH 값이 인증된 pH의 일차 표준 물질을 얻을 수 있다. 일반적인 pH 미터와 전극을 검정하는 데에는 인증된 pH 값을 가지는 표준 완충용액을 사용하므로 표준 완충용액의 pH 값 정혹도는 실제 측정된 pH 값의 실효성을 제한할 수 있다. 본 연구에서는 정확한 pH의 측정을 위해서 pH 값을 인증할 수 있는 시스템을 구축하기 위한 제반의 연구를 수행하였으며, 이를 토대로 pH 1.6∼12.5의 범위에 해당하는 완충용액의 pH를 0.005 pH 단위 이내의 불확도로 인증하였다.

• 한국응용과학기술학회지
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• 제17권3호
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• pp.174-177
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• 2000

The effect of a-sexithiophene(${\alpha}-6T$) layers on the light emitting diode (LED) were studied. The ${\alpha}-6T$ was used for a buffer layer in electroluminescent (EL) devices. Enhanced carrier (hole) injection and improved emission efficiency were observed. Carrier injection characteristics were investigated as a function of ${\alpha}-6T$ later thickness. The efficiency of the electroluminescence was proportional to the thickness of ${\alpha}-6T$ layer. The highest efficiency was observed 600A of ${\alpha}-6T$ later, which was about 1.5 times higher than that of device without ${\alpha}-6T$ later. The device with a-6T showed an operation voltage lowered by 2V. The ${\alpha}-6T$ layer can substitute hole blocking layer, and control charge injection properties.