De-icing work in highways has been changed from sand and calcium chlorides spreading to pre-wetted salt spreading since 2000s. Recently, the concern on the premature deterioration of concrete structures due to de-icing salts and its counter measurements has been increased. This paper describes the change of de-icing methods and deterioration due to chloride attack and specification of durable concrete.

활석은 T-O-T 구조의 함수 마그네슘 층상규산염 광물로서, 화학적 안정성과 흡착성 등의 특성을 가지고 있어 다양한 산업분야에서 첨가제, 코팅제 등으로 활용되어 왔다. 최근 나노 복합체의 안정성 향상을 위한 첨가제로서 활석 나노입자가 각광받고 있다. 본 연구에서는 고에너지 볼 밀을 이용하여 기계적인 방법으로 활석 나노입자를 형성하고, 분쇄시간에 따른 입자크기 및 결정도의 변화를 알아보고자 하였다. X-선 회절 분석 결과, 분쇄가 진행됨에 따라 활석의 피크 폭이 점진적으로 증가하여720분 분쇄 후, 활석은 비정질에 가까운 X-선 회절패턴을 보여준다. 레이저회절 입도 분석 결과, 약12 μm이었던 활석의 입도는 분쇄가 진행됨에 따라 약 0.45 μm까지 감소하였으나, 120분 이상 분쇄를진행하여도 뚜렷한 입도의 감소가 관찰되지 않았다. 반면, BET 비표면적은 분쇄 720분까지 꾸준히 증가하여, 분쇄에 따른 입도 또는 형태의 변화가 지속적으로 일어남을 지시한다. 주사전자현미경 및 투과전자현미경 관찰 결과, 720분 분쇄 후 약 100~300 nm 내외의 층상형 입자들이 마이크로 스케일의응집체로 존재함을 확인하였다. 이와 같은 결과는 분쇄시간이 증가함에 따라 활석의 입자크기 및 형태는 지속적으로 변화하지만, 나노입자의 특성상 재응집이 일어나 마이크로 크기의 응집체를 형성하고 있음을 지시한다. 또한 활석의 분쇄에서 판의 크기, 즉 a축, b축 방향의 길이는 감소 한계가 존재하며, 분쇄가 진행될수록 판의 두께, 즉 c축 방향의 길이 감소가 주된 분쇄 메커니즘으로 생각된다. 본연구의 결과는 나노 활석의 형성 메커니즘에 대한 이해를 고양할 수 있을 것으로 기대된다.

IT 기술의 발전에 따른 스마트폰의 보급이 안정기에 접어든 지금 스마트폰을 이용한 가상현실 시장인 Virtual Reality(VR)가 주목 받고 있으며 그 중 한 종류인 Head Mounted Display(HMD)형태의 VR기기와 다양한 콘텐츠가 대중에게 서비스되고 있다. 하지만 규제와 제약이 없고 수익성만 고려한 가상현실 영상 콘텐츠의 보급으로 VR 이용자들에게 지루함과 실망을 안겨주고 있다. 이에 가상현실 시장을 장기적으로 발전시키고 대중에게 보다 가까이 다가가기 위해서는 사용자의 니즈를 반영한 영상 콘텐츠 제작이 필요하다고 할 수 있다. 본 연구에서는 현재 서비스 되는 VR 영상 콘텐츠 중 조회 수, 언론 노출 빈도와 SNS(Social Network Service) 등에서 대중의 높은 호응을 받고 있는 영상을 선별하였고 이와 관련된 정보를 취합하여 100개 이상의 질문항목을 구성하였다. 이 후 칙센트미하이(Csikszentmihalyi)의 몰입이론과 선행연구에서 발견된 몰입변인을 적용한 총 38항목의 질문지를 최종적으로 작성하여 사용자 몰입을 측정하였다. 또한 연구 방법으로 개인의 주관적 성향을 탐색하고 분석할 수 있는 Q 방법론을 사용하였다. 결과적으로 4가지 유형이 도출되었으며 이를 통해 VR 영상 콘텐츠 이용자의 유형별 분석, 몰입 및 재사용의도를 알아보았다. 앞으로 VR 영상 콘텐츠 제작 시 연구결과로 도출된 유형별 특징 등을 반영한다면 보다 높은 몰입도를 기반으로 한 대중들의 높은 호응과 장기적 시장형성을 기대할 수 있을 것이다.

Recently, the concern on the deterioration of concrete due to de-icing salts and its counter measurements has been increased. This paper discusses the durability Assessment procedure of RC Structures against chloride attack under depicing salt environments.

In the past, concrete pavements were routinely designed and constructed to provide low-maintenance service lives of 20 to 25 years. More recently, there has been a movement toward construction of pavements with a longer initial service life of 40 or more years. This paper discusses a mixture improvement for long life concrete pavement.

Recently, the concern on the deterioration of concrete pavement due to de-icing salts and its counter measurements has been increased. Especially, a scaling phenomenon of concrete is defined as a general loss of surface mortar or mortar surrounding the coarse aggregate particles on a concrete surface. This problem is typically caused by the expansion of water due to freezing and thawing cycles and the use of de-icing chemicals. This paper discusses the testing conditions of freezing-thawing and scaling resistance.

Recently, the concern on the deterioration of concrete due to de-icing salts and its counter measurements has been increased. This paper discusses the results from investigation of pre-mature deteriorated existing road-subsidiary concrete structures and the specification of concrete quality.

Recently, the concern on the deterioration of concrete due to de-icing salts and its counter measurements has been increased. This paper discusses the results from investigation of pre-mature deteriorated existing road-subsidiary concrete structures and the specification of concrete quality.

Chloride attack, one of the reasons for early deterioration of concrete, is a phenomenon where detrimental ions such as chlorine ion penetrate into concrete from outside to diffuse and corrode the steel rebar, greatly deteriorating the durability of RC members or structures. Sources of chloride attack can be divided into the direct / indirect influence caused by seawater or its splash in the maritime environment and the de-icing salts used for the purpose of thawing the ice on the wintry road. Most notably, the usage of de-icing salts is essential for the safety of drivers and smooth traffic flows in expressways. However, they also quicken the deterioration of concretes, necessitating the countermeasures for the problem. This paper discusses the early deterioration and measurements of RC Structures under de-icing salts environments.

In recent years, many potholes in asphalt pavement occurred. In order to facilitate the repair, in this study, repair materials with high durability and excellent productivity appropriate for asphalt pre-cast materials was developed. Physical properties test and durability test of various repair materials(SMA, PMA, guss mixtures, water-reactive mixtures) were performed. In order to evaluate the workability at pre-production time of samples using repair materials were made in different shapes and sizes. Finally, after comparing mixtures, water-reactive mixture was selected as repair material. This was verified through several testing.

This study was performed to investigate the enhancement of immunomodulatory activities of Lithospermum erythrorhizon by extreme process. The extracts are WE100 (water extract for 24 hours at 100℃), WE80 (water extract for 24 hours at 80℃), EE (70% ethyl alcohol extract for 24 hours at 80℃) and EPE (extreme process for 30 minutes at 25℃, 500 MPa after 70% ethyl alcohol extracts for 3 hours at 40, 50, 60℃). Extraction yield was increased up to 5~10% by extreme process, compare to the normal extraction such as water solvent extraction, 70% ethyl alcohol solvent extraction. The cytotoxicity of the extracts was showed in the range of 12.68~15.89% at 1.0mg/ml for human lung cell (HEL299). The EPE40 was showed the lowest cytotoxicity 12.68%. The EPE60 extracted by extreme process increased the growth of human B and T cells up to 12.12×104 cells/ml and 14.88×104 cells/ml, respectively and the EPE60 greatly increased the cytokine secretion of both IL-6 and TNF-α. The extracts by extreme process also exhibited higher levels of nitric oxide production from macrophages than the lipopolysaccaharides. It can be concluded that Lithospermum erythrorhizon has immune activities and The extreme process could increase higher immune activities possibly by immunomodulatory compounds.

As the use of de-icer on expressway is increased, scaling resistance on pavement surfaces due to freezing-thawing is decreased. In this study, scaling test methods and specifications for concrete is investigated to evaluate freezing-thawing resistance of concrete.

Marine bridges are deteriorated due to the exposure under marine environment. The structure deterioration occurred by corrosion of steel in concrete is mainly relevant to chloride in seawater. The cathodic protection technique is an unique measurement to stop the corrosion of steel. In this study, the detail maintenance strategy of cathodic protection system in KEC's experience is introduced.

Concrete has been considered as a semi-permanent structural material in construction industry. However, durability of concrete member is affected by carbonation, chloride attack, and water, etc. This study discusses the cause of deteriorated RC structure of storage house for de-icing salts.

Concrete has been considered as a semi-permanent structural material in construction industry. However, durability of concrete member is affected by carbonation, chloride attack, and water, etc. Therefore, to avoid the deterioration of concrete surface treatment materials are applied. This study discusses the long-term performance and desirable quality of surface protection materials for expressway concrete structures.

The composition analysis and electron donating activity of 4 kinds of Korean wild sannamuls[Cacalia firma Komar. (CFK), Aster scaber Thunb. (AST), Ligularia fischeri (Ledeb.) Turcz. (LFT), Synurus palmatopinnatifidus (Makino) Kitam., SDN)] were investigated. The Korean edible mountainous vegetable was named a sannamul or chwinamul in Korea, generally. Most of them, the characterization of the each vegetable was reported, individually without comparative research. This study was compared the proximate compositions, mineral, dietary fiber and electron donating abilities on 2,2-diphenyl-1-picrylhydrazyl (DPPH) of sannamuls. In the chemical analysis of sannamuls, CFK was shown higher value in ash (5.4±0.18%), crude fat (2.5 ±0.14%), carbohydrate (8.1±0.21%), potassium (475.45±0.34mg) and magnesium (64.70±0.48mg) than others. Each mineral of the 3 other samples was a similar value but phosphorus in LFT was contained 62.91±0.43%. The compositions of total dietary fiber of the samples were listed CFK LFT SDN AST and the RC50 Value on DPPH radicals, LFK CFT AST SDN. These results have susggest that CFK and LFT may be useful for a funtional material to food development.

This study was performed to enhance anticancer activities of Lithospermum erythrorhizon by eluting high amount of shikonin through ultra high pressure process. Extraction yield was increased up to 5~10% by ultra high pressure process, compare to the normal extraction processes such as water solvent extraction, 70% ethyl alcohol solvent extraction. The cytotoxicity of the extracts (1.0μg/ml) from ultra high pressure process was showed the lowest cytotoxicity 13.4% for human lung cell (HEL299). The anticancer activities showed 80~85% by adding 1.0μg/ml of the extracts from ultra high pressure process in several cancer cell lines such as AGS, Hep3B, MCF-7 and HeLa cells. Among them, MCF-7 cell of the endocrine system was highest inhibited than other cells. The anticancer activities of the extracts from ultra high pressure extraction process showed 10~15%, which was higher than the extracts from normal extraction processes. From HPLC analysis of the extracts, the contents of shikonin in the extracts from ultra high pressure process was 11.42% (w/w), which was 20% higher than others. This results indicate that ultra high pressure process could increase the extraction yield of shikonin and other contents, which resulted in higher anticancer activities.

This study was performed to investigate the enhancement of cosmeceutical activities of Berberis koreana bark by different extraction processes. The extracts are WE (water extract at 100℃, control), USE (ultrasonification for 1 hours at 60℃ with water), HPE (high pressure for 5 minutes at 60℃ with water) and USE + HPE (ultrasonification process for 1 hours after high pressure for 5 minutes at 60℃ with water), respectively. The cytotoxicity of the extracts was in the range of 24.02~26.94% at 1.0 mg/ml concentration. The USE + HPE showed the lowest cytotoxicity. Compared to the WE, total phenolic and flavonoid contents in the USE + HPE increased to 121.5% and 154.2%. The USE + HPE showed the highest activity at 1.0 mg/ml concentration in 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging, inhibition activity of xanthine oxidase and superoxide dismutase (SOD)-like test, respectively. Tyrosinase inhibition of WE, USE, HPE and USE + HPE at 1.0 mg/ml concentration was measured as 17.72, 19.62, 22.83 and 24.16%, respectively. Hyaluronidase inhibition activities of the USE + HPE were higher than 20.8%~29.5% of the WE. Our results suggested that the extracts from ultrasonification process after high pressure extraction has relatively high cosmeceutical activities, and that the bark of Berberis koreana could be considered as a candidate of new functional cosmetic agents.