• 대한토목학회논문집
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• 제42권4호
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• pp.559-569
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• 2022

건설 엔지니어링은 과학기술과 지식을 접목하여 고부가가치와 일자리를 창출하는 대표적인 산업이지만 그 중요성이 저평가 되고 있다. 국토교통부의 자료에 의하면 엔지니어링 산업의 부가가치율(65.3 %)과 고용유발계수(14명 고용/10억 원)은 제조업의 3배 이상이다. 특히 시공 이전의 프로젝트 관리·기본설계 등 전방가치사슬은 총사업비의 10~15 % 미만임에도 불구하고 인프라 시설의 전체 가격과 품질을 좌우한다. 본 연구에서는 인프라 엔지니어링 플랫폼을 프로젝트 단위가 아니라 엔터프라이즈 수준의 플랫폼으로 개발하기 위하여 필요한 프레임워크, 도로 설계 업무 분류, 설계 지원 모듈 및 데이터베이스 구축 방향에 대하여 제시하고, 이를 바탕으로 클라우드 기반의 설계 플랫폼의 초기 버전을 개발하였다. 개발된 설계 플랫폼은 시간/공간 제약 없는 웹 기반 설계 업무환경을 제공하고, 해외사업 수주 및 경쟁력 확보에 크게 기여할 수 있을 것으로 기대된다.

• 한국재료학회지
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• 제31권8호
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• pp.445-449
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• 2021

Zintl compound Mg₃Sb₂ is a promising candidate for efficient thermoelectric material due to its small band gap energy and characteristic electron-crystal phonon-glass behavior. Furthermore, this compound enables fine tuning of carrier concentration via chemical doping for optimizing thermoelectric performance. In this study, nominal compositions of Mg_3.8Sb_2-xTe_x (0 ≤ x ≤ 0.03) are synthesized through controlled melting and subsequent vacuum hot pressing method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) are carried out to investigate phase development and surface morphology during the process. It should be noted that 16 at. % of excessive Mg must be added to the system to compensate for the loss of Mg during melting process. Herein, thermoelectric properties such as Seebeck coefficient, electrical conductivity, and thermal conductivity are evaluated from low to high temperature regimes. The results show that Te substitution at Sb sites effectively tunes the majority carriers from holes to electrons, resulting in a transition from p to n-type. At 873 K, a peak ZT value of 0.27 is found for the specimen Mg_3.8Sb_1.99Te_0.01, indicating an improved ZT value over the intrinsic value.

• 자원환경지질
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• 제54권5호
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• pp.573-580
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• 2021

본 연구는 산업연관표를 이용하여 골재 및 석재부문의 유발효과를 분석하였다. 먼저 골재 및 석재부문의 부가가치에 관해 정리하였으며, 이어 중간투입구조와 유발효과를 분석하였다. 부가가치구조 측면에서 골재 및 석재는 제조업에 비해 높은 피용자보수율을 보였으며, 영업잉여에 대해서도 그 외 광업에 비해 높은 비율을 보였다. 중간투입구조는 골재 및 석재 생산품을 중간투입물로 이용하는 부문과 그 투입비율을 정리하였는데, 골재 및 석재의 배분구조와 산업부문에서 골재 및 석재를 투입하는 구조를 정리하였으며, 레미콘, 콘크리트 제품 등 주요 수요자의 중간요소 투입구조 중 비중을 확인하였다. 아울러 골재 및 석재의 최대 수요자인 레미콘의 주요 투입부문에 대해서도 정리하였다. 골재 및 석재의 생산유발효과는 2015년 기준으로 0.774의 값을 보인 감응도계수에 비해 0.984의 값을 보인 영향력계수가 전체 산업에서 높은 순위를 보여 상대적으로 후방연쇄효과를 크게 갖는 것을 확인할 수 있었다. 산업연관표를 재구성하여 생산유발 효과를 검토하였는데, 한국은행의 기본부문분류에 따른 도출결과와 유사하게 영향력계수 측면에서 상대적 우위를 보이는 것으로 나타났다.

• 한국축산식품학회지
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• 제38권5호
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• pp.927-935
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• 2018

Various amounts of buckwheat powder (0%, 1%, 2%, and 3%) were added to emulsion-type pork sausages. The effects of buckwheat powder on the physicochemical characteristics of the emulsion type sausages, including proximate composition, cooking yield, viscosity, pH, instrumental color, texture profile analysis (TPA), and sensory evaluation, were determined. Increased levels of added buckwheat powder led to higher moisture (p<0.05), ash content (p<0.05 or >0.05), and cooking yield (p<0.05). However, the protein and fat contents of the sausage samples were lower (p<0.05) with higher levels of added buckwheat powder. The instrumental color and pH values were affected by the addition of buckwheat powder, which has a pH of 6.1 and associated color coordinates of $L^*=75.0$, $a^*=1.3$, and $b^*=8.7$. Meat batter with 3% buckwheat powder was shown the highest (p<0.05) viscosity indicating great formation of emulsion. There were no significant differences in the TPA among the treated samples. The viscosity value increased with increasing cooking yield in the batter ($r^2=0.7283$) i.e. the correlation coefficient between the two measurements was very high and positive. For sensory traits except for tenderness, the highest scores (p<0.05) was detected on sausages with 3% added buckwheat powder by a panel. These results suggest that the addition of 3% buckwheat powder to emulsion-type sausages produces a more beneficial meat product, with a lower fat content, greater formation of emulsion and no adverse effects on sensory properties.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기물성,응용부문
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• pp.75-77
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• 2001

The mechanical and electrical properties of the pressureless annealed SiC-$TiB_2$ electro conductive ceramic composites were investigated as functions of the transition metal of $TiB_2$. The result of phase analysis for the SiC-$TiB_2$ composites by XRD revealed $\alpha$-SiC(6H). $TiB_2$, and YAG($Al_5Y_3O_{12}$) crystal phase. The relative density showed the lowest 84.8% for the SiC-$TiB_2$ composites added with 39vol.%$TiB_2$. Owing to crack deflection, crack bridging and YAG of fracture toughness mechanism, the fracture toughness showed the highest value of $7.8\;MPa{\cdot}m^{1/2}$ for composites added with 39vol.%$TiB_2$ under a pressureless annealing at room temperature. The electrical resistivity of the SiC-27vol.%$TiB_2$ composites was negative temperature coefficient resistance(NTCR), and the electrical resistivity of the besides SiC-27vol.%$TiB_2$ composites was all positive temperature coefficient resistance(PTCR) in the temperature range of $25^{\circ}C$ to $700^{\circ}C$.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권4호
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• pp.141-146
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• 2002

The mechanical and electrical properties of the pressureless sintered SiC-TiB$_2$electroconductive ceramic composites were investigated as functions of the transition metal of TiB$_2$. The result of phase analysis for the SiC-TiB$_2$ composites by XRD revealed $\alpha$-SiC(6H), TiB$_2$, and YAG(Al$_{5}$Y$_3$O$_{12}$) crystal phases. The relative density showed the lowest 84.8% for the SiC-TiB$_2$composites added with 39vol.%TiB$_2$. Owing to crack deflection, crack bridging and YAG of fracture toughness mechanism, the fracture toughness showed the highest value of 7.8 MPa.m$^{1}$2/ for composites added with 39vol.%TiB$_2$under a pressureless annealing at room temperature. The electrical resistivity of the SiC-27vol.%TiB$_2$ composites was negative temperature coefficient resistance(NTCR), and the electrical resistivity of the besides SiC-27vol.%TiB$_2$composites was all positive temperature coefficient resistance(PCTR) in the temperature range of $25^{\circ}C$ to $700^{\circ}C$.EX>.

• 한국방사선학회논문지
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• 제13권5호
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• pp.773-778
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• 2019

X-선을 이용한 영상은 진단에 필수적인 요소지만 영상에서의 noise발생이 불가피하다. 이를 보완하기 위해 환자의 피폭선량은 낮추면서 영상의 질은 높여주는 total variation (TV) 알고리즘이 제시되었다. 본 연구의 목적은 시뮬레이션을 통해 부가 여과판의 두께에 따라 방사선 영상 촬영 시 영상의 화질에 미치는 영향을 확인하고, TV 알고리즘의 유용성을 평가하는 것이다. 부가 여과판의 두께변화에 따른 각 알고리즘 적용 시 Geant4 Application for Tomographic Emission (GATE) 시뮬레이션 영상을 이용하여 Polymethylmethacrylate(PMMA) 팬텀의 실제 크기, 모양과 재질을 동일하게 하고 대조도 대 잡음비 (contrast to noise ratio, CNR)과 변동계수 (coefficient of variation, COV)값을 비교하였으며 그 결과 TV 알고리즘 적용 시 CNR 값이 가장 높고 COV 값이 가장 낮다는 것을 확인할 수 있었다. 또한, 모든 알고리즘에서 0 mmAl을 사용할 경우 가장 우수한 CNR과 COV값을 얻을 수 있었다.

• 한국전기전자재료학회논문지
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• 제19권1호
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• pp.29-34
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• 2006

The effects of $B_2O_3$ addition on the low-temperature sintering behavior and microwave dielectric properties of $(Zn_{0.8}Mg_{0.2})TiO_3$ ceramic system were investigated. Highly dense samples were obtained at the sintering temperatures below $900^{\circ}C$. The $Q{\times}f_o$ values were determined by the microstructures and sintering shrinkages which are affected by the amount of $B_2O_3$ and sintering temperature. Temperature coefficient of resonance frequency($T_f$) changes to a positive value with increasing the amount of $B_2O_3$ due to the increased amount of rutile phase which is one of the reaction products between $(Zn_{0.8}Mg_{0.2})TiO_3$ and $B_2O_3$. For $6.19 moi.{\%}B_2O_3$-added $(Zn_{0.8}Mg_{0.2})TiO_3$ system, it exhibits ${\epsilon}_r$ = 23.5, $Q{\times}f_o$ = 53,000 GHz, and $T_f$ = 0 ppm/$^{\circ}C$ when sintered at $900^{\circ}C$ for 5 h.

• 동아시아식생활학회지
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• 제19권4호
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• pp.641-649
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• 2009

This study was conducted to investigate the effects of wheat germ on medium flour using falling number and RVA tests, as well as farinogram and rheofermentometer analyses. The wheat germ was added to the medium flour on a 3, 5, and 7% basis. Falling numbers increased with increasing amounts of wheat germ. Analysis of the RVA characteristics showed that the wheat germ additions did not have significant effects on the initial pasting temperature. In the farinogram, water absorption decreased with an increasing amount of wheat germ. Also, development time was longest in the control group and shortest in the group with the highest addition of wheat germ. The results of the effects of added wheat germ on fermentation by rheofermentometer analysis showed that the H'm value reached a maximum height at 3%. Finally, the volume of $CO_2$ lost was increased whereas the retention coefficient was decreased.

• 한국세라믹학회지
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• 제30권5호
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• pp.381-388
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• 1993

Due to the anisotropy of thermal expansion, LAS system which has low thermal expansion property is hard to obtain a dense sintered body. Therefore, the thermal expansion coefficient and the mechanical strength were decreased. In this study, mullite, which has good mechanical properties in high temperature and comparatively low thmeral expansion coefficient, was taken as a additive in LAS system. And then, sintering, thermal, and mechanical properties were investigated. The results are follows; When mullite is added in eucryptite composition (Li2O.Al2O3.2SiO2) of LAS system, the creation of liquid phase results in the densification of sintered body and the specimen sintered at 136$0^{\circ}C$ for 2 hours shows optimum sintering condition. With the addition of mullite in eucryptite composition, mechanical strength is increased by the control of grain growth. Especially, flexual strength of EM0 specimen was about double value than the basic composition. Thermal expansion coefficients of EM0 and EM15 specimens sintered at 136$0^{\circ}C$ were -8.23$\times$10-6/$^{\circ}C$ and -4.90$\times$10-6/$^{\circ}C$ in the temperature range of RT.~80$0^{\circ}C$. As the mullite content are increased, negative thermal expansion ratios are decreased.