This study was performed to determine the effects of soil and building materials on indoor radon concentration. Short-term measurements were made in the underground soil of a building along with the radon emanation rates from the phosphogypsum board used as the interior wall. The radon measurements in the soil were 9,213 Bq/m3 in the B3 level, and 3,765 Bq/m3 in the B4 level. Soil radon concentration in the B4 level was 2.4 times higher than in the B3 level. Indoor radon measurements in 50 different locations in the underground of the building, averaged from 144.3 Bq/m3 (B1), 177.0 Bq/m3 (B2), and 189.2 Bq/m3 (B3) to a high of 210.1 Bq/m3 (B4). Indoor radon concentration was increased from the lower level to the upper level. The radon emanation rates from phosphogypsum were 4,234.1 mBq/m2/h and, 450.4 mBq/kg/h. The measurement results indicated that the phosphogypsum board used as building materials as well as the soil could affect the indoor radon concentration.

이 글은 중국어 평가와 교육의 변화에 주목하면서 HSK 교과교육에서 다루어야 할 교육내용을 파악하기 위한 목적으로,『新HSK大綱(2015)』의 ‘話題大綱’을 기준 삼아 新HSK 5급 기출문제의 화제 범주를 분석하고 출제의 경향성을 고찰한 것이다. 먼저, 교육기준인『國際大綱 (2014)』의 ‘漢語敎學話題’와 평가기준인『新HSK大綱(2015)』의 ‘話題大綱’을 비교하고『新HSK大 綱(2015)』의 ‘話題’가 등급별로 범주와 항목이 체계적으로 확정되어 있음을 살펴보았다. 다음으로, 2012년과 2014년 기출문제의 화제 범주를 분석하여 新HSK 5급의 화제 범주는 사회생활을 체험해야 하는 학습자의 상황을 전제로 한 내용들이고 일상생활이 가장 높은 분포율을 보였음을 파악하였다. 마지막으로, 新HSK 5급 기출문제의 화제 범주와 항목 내용을 중심으 로 新HSK 5급의 출제 경향을 논의하였다. 일상생활, 과학기술, 자연, 경제 범주의 문제는 주로 현실을 반영하고 있고, 문학예술, 체험적 깨달음, 일과직업, 문화, 교육 범주의 문제는 주로 사회적 가치를 판단하고 있음을 밝혔다. 분포율에 근거할 때, 현실을 반영하는 문제가 가치를 판단하는 문제보다 비중이 높았음을 고찰하였다.

A new deformation micromechanism operating in the carbon cathode for aluminum electrolysis termed a ripplocation has been proposed in this paper. The creep deformation of semi-graphitic cathode was measured using a modified Rapoport equipment at 965 °C with cryolite ratio = 4.0. The characteristic of the defect was obtained by analyzing TEM photograph of the carbon cathode with different testing times. The results indicated that basal dislocations, bulk ripplocations, kink bands and delamination cracks appeared in succession in the first two stages of the creep deformation. Ripplocations in the carbon cathode make a layer of carbon atoms to glide relative to each other without damaging the in-plane bonds. Ripplocations could also attract each other and result in kink boundaries. The creep strain of the carbon cathode could be accommodated by kink band and delamination cracks during aluminum electrolysis. A more comprehensive understanding of their micromechanics behaviors is very important and could deeply influence our current knowledge of the deformation mechanism of the carbon cathode for aluminum electrolysis.

This research combines the liquid carbon precursor infiltration process for carbon/carbon composites with the fabrication procedure for organic, carbon-matrix friction materials in automotive. In the densification process, different liquid carbon precursors and numbers of densification cycle are adopted to investigate the influence on physical and mechanical properties, microstructure and tribological behavior. Experimental results indicate that the infiltration of liquid carbon precursors could improve the physical, mechanical properties and tribological performances of organic friction materials. The open porosity decreases with the number of densification cycle. Both bulk density and hardness increase with the number of densification cycle. The resin-based specimens show higher hardness and lower open porosity than those of the pitch-based specimens after each densification cycle. The tribological measurement of specimens with different carbon precursors shows that the pitch-based specimen shows lower and more stable friction coefficients and exhibits lower weight losses in comparison with other carbon precursors. Morphological observations show that a large area of smooth lubricative film was easily presented on the worn surfaces of the pitch-based specimens, whereas it was seldom observed on the worn surfaces of the preform specimen and resin-based specimens.

In this study, we investigated the properties of adhesive materials with different lightweight materials such as CFRP and Al-foam. The specimens were tested and analyzed using DCB (Double Cantilever Beam) specimens. In order to secure the reliability of the finite element method, the test and analysis were carried out, and the reliability of the finite element method was secured by using the graph of reaction force to displacement based on the experiment and analysis. The study on the adhesive failure characteristics according to the position of notch hole proceeded. Notch holes were generated at the locations of 40, 110, 150 and 190 mm from the beginning of the specimen near the bonding interface, and the analysis conditions used were the same as those used for securing reliability. The obtained study results are compared with reaction force and equivalent stress. In the case of reaction force, the overall tendency is similar but the difference in maximum reaction force is found. It was found that higher reaction forces appeared at the beginning than at the end of the bonding interface. When the equivalent stresses in the specimens were examined, the value of CFRP was seen to be 30 times higher as much as that of Al-foam.

완제품 제조업 중심의 성장을 진행한 한국경제는 소재부품산업의 경쟁력 강화를 통한 산업고도화를 지향하고 있다. 소재부품산업은 기존 핵심산업의 경쟁력 유지 및 4차 산업혁명 시대에 요구되는 신산업의 육성 측면에서 더욱 주목받고 있다. 이러한 중요성에도 불구하고, 소재부품산업의 효율적인 R&D를 위한 연구가 매우 부족한 현황이다. 본 연구는 정부의 소재부품기술개발사업 성과 데이터를 기반으로 R&D 효율성 분석과 이에 기업규모 와 협력유형이 미치는 영향에 대하여 탐색적 연구를 진행하였다. 분석결과, 전반적으로 R&D 효율성은 낮은 것으로 나타났으나, 이는 경제적 성과가 반영된 산출변수 설정에 기인한 결과로 판단한다. 중소기업이 주관기관일 경우가 대기업보다 규모 성과가 우수한 것으로 나타났으며, 산학연이 협력할 경우가 그렇지 않은 경우와 비교하여 성과가 저조한 것으로 나타났다. 본 연구의 결과는 연구개발 수행기관 및 협력유형에 따른 R&D 성과 창출에 대한 시사점을 제시하였다. 이는 국내 소재부품산업이 당면한 질적 성장을 위한 산업정책 기획, R&D 투자 및 배분 전략 수립에 도움을 줄 것으로 기대한다.

Sustainable biomass-derived porous carbons demonstrate excellent capacitive properties owing to their heteroatom-rich nature and distinct textural feature. Herein, a series of nitrogen-/phosphorus-/oxygen-containing microporous carbons (CWWN/ P/O-MPCs) have been successfully fabricated by etching in H2O2 solution, pre-treatment of camphor wood wastes with KOH solution and subsequent carbonization. As an electrode material for supercapacitors, the typical microporous carbon (CWW-N/P/O-MPCs-0.5) exhibits a remarkably high specific capacitance of 245 F g− 1 at 0.5 A g− 1, corresponding to an impressively large volumetric capacitance of 208 F m− 3, and excellent long-term stability over 10,000 cycles. The excellent electrochemical performance can be ascribed to the optimal combination of heteroatom groups and ultrafine micropores.

We fabricated glucose oxidase (GOx)-modified biosensor for detection of glucose by physical immobilization of GOx after electrochemical polymerization of the conductive mixture monomers of the 3-thiophenecarboxylic acid (TCA) and thiophene (Th) onto ITO electrode in this study. We confirmed the successfully fabrication of GOx-modified biosensor via FT-IR spectroscopy, SEM, contact angle, and cyclic voltammetry. The fabricated biosensor has the detection limit of 0.1 μM, the linearity of 0.001-27 mM, and sensitivity of 38.75 mAM-1cm-2, respectively. The fabricated biosensor exhibits high interference effects to dopamine, ascorbic acid, and L-cysteine, respectively. From these results, the fabricated GOx-modified biosensor with long linearity and high sensitivity could be used as glucose sensor in human blood sample.

Chlorella-derived activated carbon (CDAC) with a high specific surface area and hierarchical pore structure was prepared as a CO2 adsorbent and as a supercapacitor electrode material. During KOH activation of Chlorella-derived carbon, metallic K gas penetrated from the outer walls to the inner cells, and pores formed on the outer frame and the inner surface. Micropores were dominant in CDAC, contributing toward a high specific surface area (> 3500 m2/g) and a hierarchical pore structure owing to the cell walls. Consequently, CDAC exhibited a high CO2 adsorption capacity (13.41 mmol/g at 10 atm and room temperature) and afforded high specific capacitance (142 F/g) and rate capability (retention ratio: 91.5%) in supercapacitors. Compared with woody- and herbaceous-biomass-derived activated carbons, CDAC has a superior specific surface area when the precursors are used without any pretreatment under the same conditions due to their soft components such as lipids and proteins. Furthermore, developing microalgae into high-value-added products is beneficial from both economic and environmental perspectives.

Herein, the edges in carbon materials were quantitatively evaluated by summing the amount of hydrogen and the amount of functional groups without hydrogen in the material. The amount of hydrogen in the carbon material was quantitated via temperature-programmed oxidation (TPO) under an oxygen atmosphere, whereas the amount of functional groups was determined via temperature-programmed desorption (TPD) of the sample under an inert atmosphere. Consequently, the amount of edges in exfoliated carbon fibers prepared from polyacrylonitrile (PAN) (referred to as PAN-1000) was 9.4 mmol g−1. In addition, Ketjen Black (KB) and activated carbon (AC) had edge content of 1.3 and 3.6 mmol g−1, respectively. Because the total amount of functional groups of PAN-1000, KB and AC were estimated to be 8.18, 0.082 and 1.02 mmol g−1 via TPD, the total amount of edges and oxygen-containing functional groups of each sample could be quantified. The difference between amount of edges and the amount of functional groups is speculated to correspond to the amount of edges terminated with hydrogen. This study revealed that detailed information about the edges such as their proportion terminated with oxygen-containing functional groups, the species and amount of oxygen-containing functional groups via a combination of TPO and TPD.

In this technology development, we have developed an automation system after developing a material rotation mixing process so that the manual process of sound absorbing materials can be supplied in quantities. After setting up 5kgf supply of the fused acoustic material, the setting value of 5kg was automatically supplied to the molded frame to reach the quantification supply. In the process of producing noise goods between floors, the automatic compression system was developed, which was a manual operation of three persons, and the production of one person was allowed, and the production of 200 sound absorbers per day, It has improved to 450. Quantitative supply unit was developed to reach 50.7mm for target 50±3mm based on the sound absorption product thickness indication, reducing the defect rate to less.

Most structures require high reliability to ensure safety and soundness. The materials used for these structures are not only defective in the manufacturing process and construction process, but also cause generation and progress of defects due to operation of various complex use environments. In order to improve the reliability of the structure, it is very important to detect and estimate the defect size. The method of evaluating these defects without damaging the structure is a non-destructive method. In this paper, an aluminum probe of AC potential drop(ACPD) method is applied to the evaluation of two-dimensional artificial defects in ferromagnetic materials. Since the potential drop of the defect end is larger than that of the sound area, the defect can be detected and its position can be clearly confirmed, and the potential drops are changed according to the depth of the defect. The potential drop ratio (Vjmax/Vs) of the defective area has a large value for the defect. The relationship between the potential drop ratio (Vjmax/Vs) of 10 kHz and the defect depth can reduce the error in predicting the depth.