• 미생물학회지
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• 제15권2호
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• pp.85-92
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• 1977

We have in vestigated on physico-chemical and biological test of plastic transfusion set which was manufactured from the three companies after $Co^{60}\;{\gamma}-radiation$. The results obtained were as follows ; 1) In physico-chemical test generally showed a tendency to decrease of pH and tensile strength, and increase of oxidizable matter, phosphoric acid-phosphosphate and heavy metals in its eluted solution by irradiation of 2,5 Mrad. 2) In biological test including toxicity and safety test were passed but indicating haemolysis range the haemolysis test were failed to pass from 30% to 50%. 3) We have found that the raw materials of plastic transfusion set according to manufactures are all different and especially the most radioresistant raw material wss found in the product which was manufactured from C company.

• 열처리공학회지
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• 제14권5호
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• pp.275-281
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• 2001

To improve the reliability of hardness test results, Rockwell hardness round robin test was carried out for 10 laboratories. The test condition was the same with the ISO(International Standards Organization) standards. Korea Research Institute of Standards and Science(KRISS) supplied the hardness standard blocks and an indenter to laboratories for the measurement. The participating laboratories measured hardness of the specified areas on the blocks for 6 times with their own indenter as well as common indenter, respectively, and reported the results to KRISS. The result showed that quite large amount of the differences came from the indenter and it is necessary to change indenter with better quality for improved reliability in hardness measurement.

• Current Photovoltaic Research
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• 제2권3호
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• pp.140-145
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• 2014

The globally used PV qualification tests and reports the pass/fail only. Therefore, the reliability of new PV materials and parts can't be compared quantitatively with the reliability of the PV parts and materials in the market. Global PV materials and parts companies test and compare their materials, parts, and modules using the failure-to-test (FTT). However, it takes a long accelerated stress test (AST) until failure. It also needs to test the new and existing materials and parts. Therefore, it requires excessive equipment time and cost. In order to reduce the time and cost, a new reliability enhancement methodology has been developed. It tests the PV materials, parts, and modules in the global market and stores them in the PV reliability database. It reduces the time and cost of the comparison and enhancement of PV reliability. An example of the reliability enhancement of the PV encapsulant, EVA is presented.

• 대한화학회지
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• 제59권2호
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• pp.156-163
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• 2015

In Malaysia, the students' poor performance in mathematics and sciences needs immediate attention and remedies. In order to tackle this problem, an active learning environment that encourages students' question-asking capability must be molded. Transformation from traditional teacher-based approach to active-learning classroom is the key to develop question-asking capability. The classroom activity that the authors used in this study is based on the uncritical inference test to promote students' deeper thinking which encouraged students to verify facts that was previously learnt in classroom through group discussion activity. Three sets of uncritical inference test were developed and applied to Malaysian college course of basic organic chemistry. Students' answers to the impact of using uncritical inference test with a group discussion on learning and communication skills were positive.

• 한국기계가공학회지
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• 제13권6호
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• pp.145-151
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• 2014

The glass used for mobile display windows is required to have high strength. Chemical strengthening by means of ion exchange is widely used glass. The depth of the layer and the compressed stress are affected by tempering temperature and time. The purpose of this study is to investigate the range of DOL and CS, which to less breakage during reliability tests such as the ball drop test, hole drop test, 3-point bending test, drop test, and tumble test with Soda-lime Glass.

• Korean Chemical Engineering Research
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• 제50권5호
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• pp.778-782
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• 2012

최근까지 대부분의 PEMFC MEA (Membrane and Electrode Assembly) 열화 연구는 전극과 전해질막 각각 분리되어 연구되었다. 그런데 실재 PEMFC 운전조건에서는 전극과 막은 동시에 열화된다. 그래서 본 연구에서는 전극과 막열화가 동시에 일어나는 조건에서 열화 가속시험을 하였다. 실험결과 전극과 막 열화가 서로 상호작용함을 보였다. 막열화는 촉매의 활성면적 감소폭을 줄였고, 전극열화는 막의 수소투과 전류와 불소유출속도(FER) 증가폭을 감소시켰다.

• Wind and Structures
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• 제20권5호
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• pp.683-699
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• 2015

Lighting poles and antenna masts are typically high, slender and light structures. Moreover, they are often characterized by distributed eccentricities that make very complex their shape. Experience teaches that this structural type frequently suffers severe damage and even collapses due to wind actions. To understand and interpret the aerodynamic and aeroelastic behavior of lighting poles and antenna masts, this paper presents the results of static and aeroelastic wind tunnel tests carried out on a complex prismatic element representing a segment of the shaft of such structures. Static tests are aimed at determining the aerodynamic coefficients and the Strouhal number of the test element cross-section; the former are used to evaluate the critical conditions for galloping occurrence based on quasi-steady theory; the latter provides the critical conditions for vortex-induced vibrations. Aeroelastic tests are aimed at reproducing the real behavior of the test element and at verifying the validity and reliability of quasi-steady theory. The galloping hysteresis phenomenon is identified through aeroelastic experiments conducted on increasing and decreasing the mean wind velocity.

• 한국응용과학기술학회지
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• 제16권1호
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• pp.25-31
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• 1999

Algin is known as biodegradable natural polymer from marine plants. PVA/Algin blend films were prepared by solution blending method for the purpose of useful biodegradable polymer. Characteristics properties of PVA/Algin blend films such as DSC, Elongation, Tensile strength and Morphological change by SEM were determined. Tensile strength and Elongation were rapidly reduced as increasing the blend ratio of Algin. PVA/Algin blend films were found that phase separation was occured as more than 25wt% increasing the blend ratio of Algin. Blend films were observed to be less partially compatibility than 10wt% increasing the blend ratio of Algin by DSC, mechanical properties and SEM. Also, PVA/Algin blend films at the laboratory soil test(Pot Test) were completely degraded in months with four kinds of soils by microorganisms.

• Corrosion Science and Technology
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• 제20권4호
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• pp.175-182
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• 2021

Magnesium alloy is limited in the industrial field because its standard electrode potential is -2.363 V vs. NHE (Normal Hydrogen Electrode) at 25 ℃. This high electrochemical activity causes magnesium to quickly corrode with oxygen in air; chemical conversion coating prevents corrosion but causes surface defects like cracks and pores. We have examined the anti-corrosion effect of sol-gel coating sealed on the defected conversion coating layer. Sol-gel coatings produced higher voltage current and smaller pore than the chemical conversion coating layer. The conversion coating on magnesium alloy AZ31 was prepared using phosphate-permanganate solution. The sol-gel coating was designed using trimethoxymethylsilane (MTMS) and (3-Glycidyloxypropyl) trimethoxysilane (GPTMS) as precursors, and aluminum acetylacetonate as a ring-opening agent. The thermal shock resistance was tested by exposing specimens at 140 ℃ in a convection oven; the results showed changes in the magnesium alloy AZ31 surface, such as oxidization and cracking. Scanning electron microscope (FE-SEM) analysis confirmed a sealed sol-gel coating layer on magnesium alloy AZ31. Electrochemical impedance spectroscopy (EIS) measured the differences in corrosion protection properties by sol-gel and conversion coatings in 0.35 wt% NaCl solution, and the potentiodynamic polarization test and confirmed conversion coating with the sol-gel coating show significantly improved resistance by crack sealing.

• Bulletin of the Korean Chemical Society
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• 제33권2호
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• pp.613-619
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• 2012

We applied several machine learning methods for developing QSAR models for prediction of acute toxicity to fathead minnow. The multiple linear regression (MLR) and artificial neural network (ANN) method were applied to predict 96 h $LC_{50}$ (median lethal concentration) of 555 chemical compounds. Molecular descriptors based on 2D chemical structure were calculated by PreADMET program. The recursive partitioning (RP) model was used for grouping of mode of actions as reactive or narcosis, followed by MLR method of chemicals within the same mode of action. The MLR, ANN, and two RP-MLR models possessed correlation coefficients ($R^2$) as 0.553, 0.618, 0.632, and 0.605 on test set, respectively. The consensus model of ANN and two RP-MLR models was used as the best model on training set and showed good predictivity ($R^2$=0.663) on the test set.