• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 추계 학술논문 발표대회
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• pp.173-174
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• 2013

In this study, the tensile properties of sealants by heat deterioration were measured and analysed to gather the basic data of sealant because these studies do not have been investigated in Korea. Most general one-component silicone sealants were used and test specimen was I-type. The test parameters are sealant types which have different density and heat deterioration time in 80℃. As a result, the rat of reduction in area by heat deterioration was considerable increased at SR-A compared with SR-B. The tensile properties by heat deterioration decreased at SR-A because the specimen by deterioration occurred adhesive failure before tensile test. However, SR-B specimen was increased at maximum tensile stress but decreased at elongation in maximum tensile stress. Also, Maximum principal stress was measured at the edge of specimen by FEM simulation in order to find out failure points.

• 반도체디스플레이기술학회지
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• 제15권3호
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• pp.6-11
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• 2016

Silicon wafer is one of main materials in solar cell. Micro-cracks in silicon wafer are one of reasons to decrease efficiency of energy transformation. They couldn't be observed by human eye. Also, their shape is not only various but also complicated. Accordingly, their shape classification is absolutely needed for manufacturing process quality and its feedback. The performance of typical classification techniques which is principal component analysis(PCA), neural network, fusion model to integrate PCA with neural network, and support vector machine(SVM), are evaluated using pattern features of micro-cracks. As a result, it has been confirmed that the SVM gives good results in micro-crack classification.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.63-64
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• 2014

In this study, we has a purpose to estimate the joint movement responsiveness performance for the domestic products of one-component structural silicon sealants. For this purpose, we make a comparative study for the four domestic products focused on tensile properties after allowed the cyclic-movements for three days at initial step of curing phase. A joint movement range ±10% and the rate of compression and extension 3.2mm/h were assumed in those tests. As a result, the large space were induced inside the sealant by rupture, and then adhesion and cohesion failures were caused by stress concentration. The tensile properties were reduced by 15~60% in comparison with physical properties. In this case, the generating defect was caused and the service-life was decreased. Thus, further researches as relationship of test condition and products properties on this behavior would be studied.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.232-232
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• 2012

The doping of semiconducting elements is essential for the development of silicon quantum dot (QD) solar cells. Especially the doping elements should be activated by substitution at the crystalline sites in the crystalline silicon QDs. However, no analysis technique has been developed for the analysis of the activated dopants in silicon QDs in $SiO_2$ matrix. Secondary ion mass spectrometry (SIMS) is a powerful technique for the in-depth analysis of solid materials and the impurities analysis of boron and phosphorus in semiconductor materials. For the study of diffusion behaviour of B and P by SIMS, Si/$SiO_2$ multilayer films doped by B or P were fabricated and annealed at high temperatures for the activated doping of B and P. The distributions of doping elements were analyzed by SIMS. Boron found to be preferentially distributed in Si layer rather than the $SiO_2$ layer. Especially the B in the Si layers was separated to two components of an interfacial component and a central one. The central component was understood as the activated elements. On the other hand, phosphorus did not show any preferred diffusion.

• Current Photovoltaic Research
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• 제4권1호
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• pp.1-7
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• 2016

Among the various types of solar cells, silicon based two terminal tandem solar cell is one of the most popular one. It is designed to split the absorption of incident AM1.5 solar radiation among two of its component cells, thereby widening the wavelength range of external quantum efficiency (EQE) spectra of the device, in comparison to that of a single junction solar cell. In order to improve the EQE spectra further and raise short circuit current density ($J_{sc}$) an optimization of the tradeoff between the top and bottom cell is needed. In an optimized cell structure, the $J_{sc}$ and hence efficiency of the device can further be enhanced with the help of light trapping scheme. This can be achieved by texturing front and back surface as well as a back reflector of the device. In this brief review we highlight the development of light trapping in the silicon based tandem solar cell.

• 한국태양에너지학회 논문집
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• 제32권3호
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• pp.11-18
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• 2012

To expect accurately the maximum power of solar cell module under various installation conditions, it is required to know the performance characteristics like temperature dependence. Today, the PV (photovoltaic) market in Korea has been growing. Also BIPV (building integrated photovoltaic) systems are diversified and become popular. But thermal dependence of PV module is little known to customers and system installers. In IEC 61215,a regulation for testing the crystalline silicon solar cell module, the testing method is specified for modules. However there is limitation for testing the module with diverse application examples. In extreme installation method, there is no air flow between rear side of module and ambient, and it can induce temperature increase. In this paper, we studied the roof type installation of PV module on the surface of one-axis tracker system. We measured temperature on every component of PV module and compared to open-rack structure. As a result, we provide the foundation that explains temperature characteristics and NOCT (nominal operation cell temperature) difference. The detail description will be specified as the following paper.

• 한국재료학회지
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• 제12권5호
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• pp.414-422
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• 2002

Three different multi-component white cast irons alloyed with Cr, V, Mo and W were prepared in order to study their as-cast and solidification structures. Three combinations of the alloying elements were selected so as to obtain the different types of carbides and matrix structures : 3%C-10%Cr-5%Mo-5%W(alloy No.1), 3%C-10%V-5% Mo-5%W(alloy No. 2) and 3%C-17%Cr-3% V(alloy No.3). The as-cast microstructures were investigated with optical and scanning electron microscopes. There existed two different types of carbides, $M_7C_3$ carbide with rod-like morphology and $M_6C$ carbide with fishbone-like one, and matrix in the alloy No. 1. The alloy No. 2 consisted of MC carbide with chunky and flaky type and needle-like $M_2C$ carbide, and matrix. The chunky type referred to primary MC carbide and the flaky one to eutectic MC carbide. The morphology of the alloy No. 3 represented a typical hypo-eutectic high chromium white cast iron composed of rod-like $M_7C_3$ carbide which is very sensitive to heat flow direction and matrix. To clarify the solidification sequence, each iron(50g) was remelted at 1723K in an alumina crucible using a silicon carbide resistance furnace under argon atmosphere. The molten iron was cooled at the rate of 10K/min and quenched into water at several temperatures during thermal analysis. The solidification structures of the specimen were found to consist of austenite dendrite(${\gamma}$), $ ({\gamma}+ M_7C_3)$ eutectic and $({\gamma}+ M_6C)$ eutectic in the alloy No. 1, proeutectic MC, austenite dendrite(${\gamma}$), (${\gamma}$+MC) eutectic and $({\gamma}+ M_2C)$ eutectic in the alloy No. 2, and proeutectic $M_7C_3$ and $ ({\gamma}+ M_7C_3)$ eutectic in the alloy No 3. respectively.

• 한국세라믹학회지
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• 제17권4호
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• pp.188-196
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• 1980

To investigate the corrosion behavior of the clay-bonded kaolin chamotte by molten aluminum, the mixture of 20 wt% fire clay and 80 wt% kaolin chamotte was prepared and fired in the temperature range 900~120$0^{\circ}C$. The specimens fired at each temperature were reacted with molten aluminum at 90$0^{\circ}C$. The results obtained in this experiment are as followed. 1) It was confirmed through X-ray diffraction analysis that the clay-bonded kaolin chamotte exposed to molten aluminum suffered penetration by the reaction of aluminum with silica forming alumina and metallic silicon. 2) Penetration was independent whether the silica existed as free or one component of mullite. 3) Penetration of the specimen fired at 90$0^{\circ}C$ was negligible while the others fired above 100$0^{\circ}C$ showed remarkable penetration. 4) Penetration rate at 90$0^{\circ}C$ was parabolically increased with the holding time as in the case of metal oxidation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 D
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• pp.1309-1311
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• 1998

$Pb_{1-x}La_xTi_{1-x/4}O_3$ (PLT(x)) thin film has been regarded as one of the most promising materials for applications of sensor, optic devices, and memory devices, because it exhibits various properties as changing the amount of Lanthanum component. So we have prepared PLT thin films on platinized silicon (actually Pt/Ti/$SiO_2$/Si) substrates in oxygen ambient by laser ablation. Energy dispersive X-ray (EDX) revealed that the stoichiometric thin films were fabricated.

• 센서학회지
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• 제11권4호
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• pp.191-199
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• 2002

This paper presents the design concept, theoretical investigation, and fabrication of a six-degree of freedom (6-DOF) turbulent flow micro sensor utilizing the piezoresistive effect in silicon. Unlike other flow sensors, which typically measure just one component of wall shear stress, the proposed sensor can independently detect six components of force and moment on a test particle in a turbulent flow. By combining conventional and four-terminal piezoresistors in Si (111), and arranging them suitably on the sensing area, the total number of piezoresistors used in this sensing chip is only eighteen, much fewer than the forty eight piezoresistors of the prior art piezoresistive 6-DOF force sensor.