• 산업융합연구
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• 제19권1호
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• pp.27-32
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• 2021

노벨 엔지니어링은 독서를 통하여 문제를 찾아내고, 이를 공학적인 방법으로 해결해보는 융합수업모형이다. 이제까지의 노벨 엔지니어링 연구는 온전히 대면으로 진행되어왔다. 그러나 COVID-19 사태 이후를 대비하여 온라인과 오프라인 수업을 병행한 블렌디드 러닝의 연구가 매우 필요하다. 그래서 본 연구에서는 블렌디드 노벨 엔지니어링 수업이 초등학생들의 창의적 문제해결력 향상에 미치는 영향에 대해서 연구하였다. 연구 결과, 이 수업이 자기 확신 및 독립성, 확산적 사고, 비판적 사고, 동기적 요소 요인에서 기존의 문제해결 프로젝트 수업보다 더 높은 효과가 있다는 것이 증명되었다. 이는 블렌디드 노벨 엔지니어링 수업이 2015 개정 교육과정에서 제시한 역량 중심 수업을 위해서 매우 효과적이라는 것을 의미한다. 이 연구로 인하여 코로나 이후 시대에 블렌디드 노벨 엔지니어링이 학교 현장에 확산되어 정착될 수 있기를 기대한다.

• Macromolecular Research
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• 제16권7호
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• pp.596-603
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• 2008

To improve the mechanical properties, dimensional stability and blood compatibility, the biomedical material $Pellethene^{(R)}$ was blended with multiblock polyurethane (MPU) containing phospopholipid/long alkyl chain (C-18) at the various MPU contents and crosslinked using dicumyl peroxide as a crosslinking agent. The maximum MPU content for stable $Pellethene^{(R)}$/MPU blended films was approximately 30 wt%. The optimum crosslinking agent content and crosslinking time with respect to the mechanical properties were 4 wt% and 3 h, respectively. The mechanical properties (tensile strength and elongation at break) and water absorption of the crosslinked blend film increased with increasing MPU content. The test of platelet adhesion on the surfaces of the crosslinked blend film showed a decrease in the level of platelet adhesion from 70% to 6% with increasing MPU content from 0 to 30 wt%. These results suggest that the crosslinked $Pellethene^{(R)}$/MPU-30 (MPU content: 30 wt%) sample has strong potential as a novel material for blood compatible material applications.

• International Journal of Concrete Structures and Materials
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• 제7권3호
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• pp.225-238
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• 2013

In this study, a two-layer feed-forward neural network was constructed and applied to determine a mapping associating mix design and testing factors of cement-nano silica (NS)-rice husk ash ternary blended concrete samples with their performance in conductance to the water absorption properties. To generate data for the neural network model (NNM), a total of 174 field cores from 58 different mixes at three ages were tested in the laboratory for each of percentage, velocity and coefficient of water absorption and mix volumetric properties. The significant factors (six items) that affect the permeability properties of ternary blended concrete were identified by experimental studies which were: (1) percentage of cement; (2) content of rice husk ash; (3) percentage of 15 nm of $SiO_2$ particles; (4) content of NS particles with average size of 80 nm; (5) effect of curing medium and (6) curing time. The mentioned significant factors were then used to define the domain of a neural network which was trained based on the Levenberg-Marquardt back propagation algorithm using Matlab software. Excellent agreement was observed between simulation and laboratory data. It is believed that the novel developed NNM with three outputs will be a useful tool in the study of the permeability properties of ternary blended concrete and its maintenance.

• International journal of advanced smart convergence
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• 제4권1호
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• pp.154-161
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• 2015

A novel process has successfully been developed by overcoming major difficulties through the elimination of number of process steps involved in the Classical Transesterification reaction during the preparation of Fatty Acid Methyl/Ethyl Ester (FAME.FAEE) called biodiesel. The Classical process with cost intensive process steps such as the utilization of excess alcohol, needing downstream distillation for the recovery and reutilization of excess alcohol/cosolvent, unrecoverable homogenous catalyst which consumes vast quantity of fresh distilled water during the purification of the product and downstream waste water treatment before its safe disposal to the surface water body. The Novel Process FAME/FAEE is produced from any vegetable oil irrespective of edible or inedible variety using sonication energy. The novelty of the finding is the use of only theoretical quantity of alcohol along with a co-solvent and reduced quantity of homogeneous catalyst. Under this condition neither the homogeneous catalyst goes to the FAME layer nor is the distillation needed. The same ester also has been prepared in high pressure high temperature reactor without using catalyst at sub critical temperature. The quality of prepared biodiesel without involving any purification step meets the ASTM standards. Blended Biodiesel with Common Diesel Fuel (CDF) and FAME is prepared, characterized and used as fuel in the Kirloskar make CI Engines. The evaluation of the engine performance result of pure CDF, B05 biodiesel, B10 biodiesel of all types of biodiesel prepared by using the feedstock of Soybean (Glycine max) and Karanja (Pongamia pinnate) oil along with their mixed oil provides useful information such as brake power, brake thermal efficiency, brake specific fuel consumption, etc, and established it as ideal fuel for unmodified CI engine.

• Bulletin of the Korean Chemical Society
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• 제32권7호
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• pp.2316-2318
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• 2011

A novel technology has been developed for the synthesis of thioglycolic acid (TGA)-capped CdSe quantum dots (QDs) in aqueous medium. The reaction was carried out in air atmosphere with one-pot by using $SeO_2$ to replace Se or $Na_2Se$. The technological parameters including refluxing time, pH values and molar ratios of selenium to cadmium had significant influence on the luminescence properties of CdSe QDs. Furthermore, the obtained QDs were characterized by fluorescent spectroscopy, X-ray powder diffraction (XRD) and transmission electron microscopy (TEM), respectively. The results demonstrated that the CdSe QDs were of zinc-blended crystal structure in a sphere-like shape.

• Advances in nano research
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• 제5권2호
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• pp.99-111
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• 2017

Nano particles have been gaining increasing attention and applied in many fields to fabricate new materials with novel functions due to their unique physical and chemical properties. In the present study two nano materials, namely nano silica (NS) and nano clay metakaolin (NMK) were partially replaced with ordinary Portland cement (OPC). The replacement level was varied from 0.5 to 2.0% in OPC and blended in cement mortar with a water cement ratio of 0.40. Mechanical property studies and durability experiments such as compressive strength, tensile strength, water absorption, depth of chloride penetration test. Nano silica was synthesized from rice husk ash and analyze the size using particle size analyzer. The results indicate that the compressive and tensile strength of the cement mortars containing nano materials were higher strength compared to the plain mortar with the same water cement ratio.

• 한국CDE학회논문집
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• 제12권5호
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• pp.354-365
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• 2007

We present novel methods to generate a sequence of shapes that represents the pattern of morphological development or transformation of Bezier curves. The presented methods utilize the intrinsic geometric structures of a Bezier curve that are derived from rib and fan decomposition (RFD). Morphological development based on RFD shows a characteristic pattern of structural growth of a Bezier curve, which is the direct consequence of development path defined by fans. Morphological transformation based RFD utilizes development patterns of source and target curves to mimic the theory of evolutionary developmental biology: although the source and target curves are quite different in shapes, we can easily find similarities in their younger shapes, which makes it easier to set up feature correspondences for blending them. We also show that further controls on base transformation for intensity of feature blending, and extrapolation can compensate the immaturity of blended curves. We demonstrate the experimental results where transformation patterns are smoother and have unique geometric style that cannot be generated using conventional methods based on multi-linear blending.

• 한국산학기술학회논문지
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• 제17권12호
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• pp.504-510
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• 2016

본 연구는 현재 정보통신기술 시대에 요구하는 문제해결 능력을 갖춘 몽골의 인재를 양성하기 위하여 효율적으로 학습할 수 있도록 하기 위한 방안으로 몽골 공학대학에서 적합한 Blended PBL 모형을 제시한다. BPBL은 학습자 중심의 교육 방법이다. 현재 몽골에서 빠르게 변화하는 교육환경과 학생의 요구에 부응하기 위해 공학 교수법의 변화가 필요하다. 따라서 몽골 공학 교육의 발전을 위한 BPBL 학습을 도입하며 공학 교수자들에게 더 많은 교육의 기능성을 제공 할 것이다. 최근에는 몽골에서 대학 내에 '교수학습센터'를 설립하여 '가르치는 방법'에 대한 교육과 지원을 교수자들에게 제공하고 있지만, 아직도 단편적이고 일회적인 특강 형식의 지원이 대부분이다. 이런 이유로 많은 교수들은 '그저 자신이 배운 방식대로' 가르친다. 아직도 공학 교수방법은 교수자 중심으로 이루어지고 있다. 앞으로 급변하는 미래 정보사회를 전망할 때, 몽골공과대학의 목표해야 할 기본적인 방향은, 규제의 철폐, 완화를 통해서 진정으로 풍요롭고 활력 있는 사회를 형성하고 있으며 최근의 공과대학 강사와 사회는 익숙한 구식 방법 말고 다른 공학 교육 방법을 요구하고 있다. 새로운 공학 교육 방법의 개발에 효과적인 엔지니어링 전략을 사용하는 것은 성공으로 이어질 것입니다.

• Advances in concrete construction
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• 제9권6호
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• pp.537-545
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• 2020

In order to reduce the usage of cement slurry in grouting engineering and consume the tunnel excavation waste soil, a new geopolymeric grouting material (GGM) was prepared by combine completely weathered granite (CWG) and blast-furnace slag (BFS), which can be applied to in-situ grouting treatment of completely weathered granite strata. The results showed CWG could participate in the geopolymerization process, and GGM slurry has the characteristics of short setting time, high flowability, low viscosity, high stone rate and high mechanical strength, and a design method of grouting pressure based on viscosity evolution was proposed. By adjusted the content of completely weathered granite and alkali activator concentration, the setting time of GGM were ranged from 5 to 30 minutes, the flowability was more than 23.5 cm, the stone rate was higher than 90%, the compressive strength of 28 days were 7.8-16.9 MPa, the porosity were below 30%. This provides a novel grouting treatment and utilizing excavated soil of tunnels in the similar strata.

• Membrane and Water Treatment
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• 제9권4호
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• pp.221-231
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• 2018

A new procedure to produce poly(vinylidene fluoride)/boron nitride hybrid membrane is presented for application in membrane distillation (MD) process. The influence of hexagonal boron nitride (h-BN) incorporation on the performance of the polymeric membranes is studied through the present investigation. For this aim, h-BN nanopowders were successfully synthesized using the simple chemical vapor deposition (CVD) route and subsequent solvent treatments. The resulting h-BN nanosheets were blended with poly(vinylidene fluoride) (PVDF) solution. Then, the prepared composite solution was subjected to phase inversion process to obtain PVDF/h-BN hybrid membranes. Various examinations such as scanning electron microscopy (SEM), wettability, permeation flux, mechanical strength and liquid entry pressure (LEP) measurements are performed to evaluate the prepared membrane. Moreover, Air gap membrane distillation (AGMD) experiments were carried out to investigate the salt rejection performance and the durability of membranes. The results show that our hybrid PVDF/h-BN membrane presents higher water permeation flux (${\sim}18kg/m^2h$) compared to pristine PVDF membrane. In addition, the experimental data confirms that the prepared nanocomposite membrane is hydrophobic (water contact angle: ${\sim}103^{\circ}$), has a porous skin layer (>85%), as well competitive fouling resistance and operational durability. Furthermore, the total salt rejection efficiency was obtained for PVDF/h-BN membrane. The results prove that the novel PVDF/h-BN membrane can be easily synthesized and applied in MD process for salt rejection purposes.