During a long-term operation of polymer electrolyte membrane fuel cells(PEMFCs), the fuel cell performance may degrade due to severe agglomeration and dissolution of metal nanoparticles in the cathode. To enhance the electrochemical durability of metal catalysts and to prevent the particle agglomeration in PEMFC operation, this paper proposes a hybrid catalyst structure composed of PtCo alloy nanoparticles encapsulated by porous carbon layers. In the hybrid catalyst structure, the dissolution and migration of PtCo nanoparticles can be effectively prevented by protective carbon shells. In addition, O2 can properly penetrate the porous carbon layers and react on the active Pt surface, which ensures high catalytic activity for the oxygen reduction reaction. Although the hybrid catalyst has a much smaller active surface area due to the carbon encapsulation compared to a commercial Pt catalyst without a carbon layer, it has a much higher specific activity and significantly improved durability than the Pt catalyst. Therefore, it is expected that the designed hybrid catalyst concept will provide an interesting strategy for development of high-performance fuel cell catalysts.

Rare earth elements (REEs) are considered to be vital to modern industry due to their important roles in applications such as permanent magnets, automobile production, displays, and many more. The imbalance between demand and supply of REEs can be solved by recycling processes. Regarding the needs of industry and society, the International Organization for Standardization, Technical Committee 298 (ISO/TC298) Rare Earths has been recently launched for developing international standards on rare earth elements. In accordance with the suggestion of its constituents, it is tentatively working to develop the appropriate standards under five working groups (WG) on terms and definitions (WG1), element recycling (WG2), environmental stewardship (WG3), packaging, labelling, marking, transport, and storage (WG4), and testing analysis (WG5). The scope and structure of ISO/TC298 on the topic of rare earths is discussed in this document.

Crack in concrete surfaces is one of the earliest signs of decomposition of the essential structure and constant exposure will cause serious damage to the structure and environment. In most of the safety assessment and fracture mechanic applications proposed that these cracks and defects eventually will grow and will have potential lead to in-service failure. Crack in concrete surfaces is one of the earliest signs of decomposition of the essential structure and constant exposure will cause serious damage to the structure and environment. Currently, non-destructive methods are getting popular in the field of inspecting defects in structure and one of them in trends is that using the thermographic image to detect hidden effects. However, the accuracy of the thermal camera, also called resolution, is highly dependent on camera variables such as lens, detector, sensitivity etc. Also, the most important question that needs to be answered for this research is what happens to the image in fog, rain or other climatic conditions where the camera detects crack which exceptionally smaller than most thermographic applications detects. This paper investigates the accuracy of thermal images obtained by the thermal camera under various weather condition and aims at providing information about optimum choice of environmental condition where the more favorable thermal images can be obtained and increase survey reliability and accuracy of the analysis.

Ameloblastoma is a benign odontogenic tumour of epithelial origin and comprises 1% of maxillomandibular tumors or cysts. The incidence of pathological changes such as ameloblastoma from the follicle of impacted third molar was reported to have low incidence. However, there are many reports that asymptomatic third molars are related with various pathological conditions. A case of ameloblastoma secondary to third molar extraction and subsequent sagittal split ramus osteotomy (SSRO) had not been reported. At the right ramus area, radiolucent lesion had been noted at 6 years after the surgical extraction of the third molar followed by SSRO for the mandibular prognathism. The lesion was proved to be the basal cell type ameloblastoma. There had been no significant bony lesion before or 1 year after the SSRO. The tumour was successfully removed and there was no evident recurrence at 4 year of the follow up after the removal of the ameloblastoma. There are some reports suggesting the pathologic potential of the pericoronal tissues of impacted third molars to develop odontogenic keratocysts and ameloblastomas. The current case reports a rare possibility of ameloblastic change at the site of uneventful healing after third molar extraction and orthognathic surgery.

This study investigated the effect of the grinding media of a ball mill under various conditions on the raw material of copper powder during the milling process with a simulation of the discrete element method. Using the simulation of the three-dimensional motion of the grinding media in the stirred ball mill, we researched the grinding mechanism to calculate the force, kinetic energy, and medium velocity of the grinding media. The grinding behavior of the copper powder was investigated by scanning electron microscopy. We found that the particle size increased with an increasing rotation speed and milling time, and the particle morphology of the copper powder became more of a plate type. Nevertheless, the particle morphology slightly depended on the different grinding media of the ball mill. Moreover, the simulation results showed that rotation speed and ball size increased with the force and energy.

사탕무씨스트선충(Heterodera schachtii)은 최근 우리나라의 배추 재배지의 문제선충이다. 본 연구는 사탕무씨스트선충의 밀도와 배추의 묘 령이 사탕무씨스트선충의 증식에 미치는 영향을 알아보기 위하여 수행하였다. 접종농도가 높은(4마리 유충 또는 알/g 토양) 처리에서 씨스트 수나 암컷 또는 알 수가 유의하게 높았다. 40일 묘령 배추에 고밀도 선충 접종 시 30일이나 60일 후 다른 어린 묘령 배추(파종처리, 20일묘, 30일묘)에 비하여 증식 선충 밀도가 높았다. 높은 선충 밀도 조건에 묘령이 오래 된 모종 식재 시 선충 증식율이 높기 때문에 사탕무씨스트선충 관리를 위해서 는 정식 모종의 묘령 고려가 필요하다.

유기합성 농약의 과다사용은 환경오염, 살충제 저항성 발달, 비표적 생물에 대한 영향 등 부작용의 원인이 되고 있다. 유기합성 농약의 대체약 제로 포유동물에 저독성인 식물기원 물질이 각광을 받게 되었다. 이란 서양가새풀(Achillea millefolium L.) 정유성분의 훈증독성은 국제적 저장작 물 해충인 머리대장가는납작벌레(Oryzaephilus surinamensis L.)의 방제제로 연구된 바 있다. 이 식물 정유의 화학적 성분을 가스크로마트 그래피 (MS)를 이용하여 분석하였다. 살충실험 결과 처리농도에 따라 유의한 살충률을 나타냈다. 처리농도와 살충률 간 양의 상관관계가 있었다. 반치사 농도(LC50)는 17.977 μl/L 이었다. 주요 성분은 1,8-Cineole (13.17%), nerolidol (12.87%), α-cubebene (12.35%), artemisia ketone (6.69%), α-terpineol (5.27%), alloaromadendrene oxide (4.71%) 및 borneol (3.99%) 이었다. 전체 동정된 화합물의 96.35%는 Terpenic 화합물로 monoterpene hydrocarbons (8.19%), monoterpenoids (44.23%), sesquiterpene hydrocarbons (21.69%) 및 sesquiterpenoids (22.24%)를 포함하고 있었다. 본 결과는 terpene이 풍부한 서양가새풀 정유가 머리대장가는납작벌레의 안전한 생물농약으로 고려될 수 있음을 보여주었다.

수소원자는 금속 표면에 흡착하여 해리되고 금속격자 사이를 이동해 다시 수소분자로 재결합되어 탈착할 수 있으며 이러한 과정으로 수소는 금속을 통해 투과할 수 있다. 특히 수소원자는 팔라듐에서 높은 용해도와 이동도를 보여 우수한 수소투과 특성을 나타낸다. 본 연구에서는 무전해 도금을 이용하여 Pd계 금속을 α-Al2O3 중공사막 지지 체에 증착시켜 수소투과 실험을 진행하였다. Pd을 증착하기 전, Seeding 과정을 통해 지지체에 Pd 핵을 심어 금속의 증착이 용이하도록 하였으며, 중공사막 지지체의 표면 특성에 따른 Pd 증착상태를 확인하였다.

PURPOSES : The objective of this study is to develop a simple regression model in designing the asphalt concrete (AC) overlay thickness using the Mechanistic-empirical pavement design guide (MEPDG) program. METHODS: To establish the AC overlay design equation, multiple regression analyses were performed based on the synthetic database for AC thickness design, which was generated using the MEPDG program. The climate in Seoul city, a modified Hirsh model for determining dynamic modulus of asphalt material, and a new damaged master curve approach were used in this study. Meanwhile, the proposed rutting model developed in Seoul city was then used to calibrate the rutting model in the MEPDG program. The AC overlay design equation is a function of the total AC thickness, the ratio of AC overlay thickness and existing AC thickness, the ratio of existing AC modulus and AC overlay modulus, the subgrade condition, and the annual average daily truck traffic (AADTT). RESULTS: The regression model was verified by comparing the predicted AC thickness, the AADTT from the model and the MEPDG. The regression model shows a correlation coefficient of 0.98 in determining the AC thickness and 0.97 in determining AADTT. In addition, the data in Seoul city was used to validate the regression model. The result shows that correlation coefficient between the predicted and measured AADTT is 0.64. This indicates that the current model is more accuracy than the previous study which showed a correlation coefficient of 0.427. CONCLUSIONS: The high correlation coefficient values indicate that the regression equations can predict the AC thickness accurately.

팥바구미(Callosobruchus chinensis)는 팥 종실의 이용성을 제한하는 가장 주요한 해충으로 팥 성숙기에 팥 종실의표면에 산란하고 부화유충은 곧바로 종실 안으로 들어감으로 수확한 팥은 이미 팥바구미에 감염된 상태이다. 그래서팥을 상온에 두면 팥에서 팥바구미가 출현하여 팥을 이용할 수 없게 된다. 따라서 상온에서 팥바구미로부터 팥을안전하게 보관할 수 있는 방법을 강구하고자 실내에서 탈산소제, 제습제 및 가스제거제를 이용하여 팥바구미 감염팥에서팥바구미의 출현을 조사하였다. 팥바구미 알을 가진 팥 종실에 탈산소제, 가스제거제, 제습제, 탈산소제+가스제거제,탈산소제+제습제, 가스제거제+제습제 처리에 따른 팥바구미 성충의 출현율은 각각 10%, 36,7%, 0.0%, 10.0%, 3.3%,13.3% 이었다. 팥바구미 유충감염 팥종실에서 탈산소제, 가스제거제, 제습제, 탈산소제+가스제거제, 탈산소제+제습제,가스제거제+제습제 처리에 따른 팥바구미 성충의 출현율은 각각 83.3%, 75.0%, 33.3%, 90.0%, 26.7%, 55.0% 이었고,팥바구미 번데기감염 팥종실에서 탈산소제, 제습제, 탈산소제+제습제 처리에 따른 팥바구미 성충의 출현율은 각각36.7%, 43.3%, 30.0% 이었다. 그리하여 팥바구미 성충의 출현율은 탈산소제와 제습제 조합 처리에서 현저히 낮았으며,특히 팥바구미 알처리에서 가장 낮았고, 다음은 번데기로 나타났다. 따라서 탈산소제와 제습제를 팥과 함께 용기에넣고 밀봉하면 팥바구미의 발육 및 증식을 억제하여 팥바구미로부터 팥을 안전하게 보관할 수 있을 것으로 여겨진다.

연구에서는 북부 터키에서 Paranemastoma속의 통거미 1신종을 기재하였다. 본 종Paranemastoma karolianus의 다리, 등면 표피 및 생식 기의 미세구조를 제시하였다. 본 신종과 유사종과의 구별점에 대하여 고찰하였다.

남한산 큰자색호랑꽃무지는 그 동안 일본에 분포하는 Osmoderma opicum으로 동정되어 왔으며, 국내에서는 그 희귀성에 의해 멸종위기종으 로 다루어지고 있지만, 남한 개체군에 대한 면밀한 종의 실체에 대한 구명은 없었다. 이에 대해, 남한산 큰자색호랑꽃무지와 유라시안 근연종에 대 해 형태 및 COI유전자 염기서열을 비교를 실시하였다. 결과적으로, 남한산 개체군은 형태적으로 극동러시아에 분포하는 O. caeleste와 동일하였다. 따라서, 남한산 큰자색호랑꽃무지는 O. caeleste임을 제안한다.

A class of phenolphthalein anilide based poly(ethersulfone) (PES) block copolymers containing pendent quaternary ammonium (QA) groups was prepared as anion exchange membranes by reaction involving nucleophilic substitution, benzylic bromination, quaternization and anion exchange with hydroxide ions. Hexafluorobenzene (HFB) was utilized as a linkage group between the hydrophobic and hydrophilic oligomer blocks. Nano-phase separated membrane morphology due to block structure of poly (ethersulfone) serves for better management of absorbed water for higher hydroxide conductivity with good thermal, and dimensional stability. The water uptake, swelling ratio, conductivity, and chemical stability of the copolymer membranes were comparatively investigated.

Geotextile tubes are excellent design strategies for both shoreline protection and dewatering of fine materials. A difficulty with regard to designing geotextile tubes is the matching of the appropriate fabric with the site-specific infilled material and the unavailability of a test to determine the soil-geotextile consolidation properties. Existing methods simulate and predict the final tube shape based on the initial and final unit weights of the infill but the time required to reach the final shape or the compatibility of the infill are not being considered. This study proposes an improved hanging bag test to evaluate the compatibility of an infill with the geotextile fabric, and at the same time, to obtain the soil-geotextile consolidation properties. With the obtained consolidation properties, a big prototype simulation was possible, explaining the deformation behavior of the tube in the field. An analytical procedure used in modeling the tube was coupled with the large strain consolidation theory to simulate the filling and dewatering process.

Reactive oxygen species (ROS) induces oxidation against various biomolecules including fatty acids. Calcium-independent cellular phospholipase A2 (iPLA2) has been known to function maintenance of fatty acids in phospholipids in mammals. An insect iPLA2 (Pi-iPLA2) was predicted from transciptomes of the Indianmeal moth, Plodia interpunctella. It was expressed in all developmental stages from egg to adult. RNA interference (RNAi) against Pi-iPLA2 was performed with specific double-stranded RNA (dsRNA) with more than 70% efficiency in reduction of its expression. Under this RNAi condition, P. interpuctella exhibited developmental retardation with significant accumulation of lipid peroxidation measured by the amount of melondialdehyde

톱다리개미허리노린재는 3월 중·하순부터 11월 중·하순까지 지속적으로 발생하며, 월동성충은 5월 상순, 1회 성충은 8월 하순에 발생피크를 나타내고, 여름철을 제외하고는 농경지보다 산림지에서 발생량이 현저히 많았다. 월동한 톱다리개미허리노린재는 5월 중순경에 산란하고, 5월 하순부터 부화하여 1회 성충이 7월 하순에 콩포장으로 가장 많이 비래한다. 콩포장에서 톱다리개미허리노린재는 일반적으로 개화기부터 발생하기 시작하고, 꼬투리가 달리는 시기부터 발생량이 크게 증가하여 수확기까지 지속적으로 발생한다. 집합페로몬에 의한 톱다리개미허리노린 재의 유인효과는 3성분(EZ:EE:MI)보다 4성분(EZ:EE:MI:OI)에서 약 30% 이상 많이 유인되며, 집합페로몬과 두류종실 을 조합하면 노린재의 유인효과가 약 39∼60% 정도 증가하는데, 특히 청자콩과의 조합에서 유인효과가 가장 높았다. 톱다리개미허리노린재의 일주활동시간대는 8월에는 14:00∼16:00에, 9월 하순부터는 12:00∼14:00에 가장 많이 유인 되어 계절에 따라 차이가 있었다. 트랩의 종류에 따른 톱다리개미허리노린재의 유인효과는 기존의 통발트랩보다 로케트트랩에서 1.5배 이상 많이 유인되었으며, 로케트트랩의 내부에 솔라팬을 장착하면 노린재의 유인효과는 1.9배 이상 증가하였고, 여기에 LED를 장착하면 노린재의 유인효과는 1.8배 증가되었다. 또한 로케트트랩의 날개판 하부에 안착판을 추가하면 노린재의 유인효과 25% 이상 증가되었다. 로케트트랩에 이종 노린재류의 집합페로몬을 동시에 주입하여도 대상 노린재류의 유인효과가 간섭받지 않고 잘 유인되었다.

Riboswitches are structured RNA motifs that can directly bind specific metabolites. The binding of metabolites further regulates downstream metabolism eliminating the need for any regulatory proteins. We searched for novel bacterial vitamin B1 binding riboswitches in the metagenome of sun-dried saline soil. Soil microbial metagenomes were studied using NGS analysis. A total of approximately 50 Gb of the sequence data was obtained by Hi-seq and 454 GS FLX sequencing, and these sequences were subjected to riboswitch search. Hi-seq generated 614 contigs showing similarity to riboswitches, while 454-based sequencing generated 383 similar contigs. We matched whole metagenome contigs to local BLAST databases constructed using 91 previously known bacterial vitamin B1 thiamine pyrophosphate (TPP)-box motifs, and 11 SAM S-box motifs. Repetitive BLAST comparisons to local BLAST databases with nucleotide sequences from NGS identified 14 novel TPP-box motifs, and 7 S-box motifs respectively from the metagenome contigs. Further, RNA secondary structure analysis with public databases Rfam, and RibEx using these 21 riboswitch candidates revealed one contig, D8PYI to possess the most probable TPP-box structure. We constructed intragenic synthetic riboswitches to investigate whether the TPP-box motif region in D8PYI could harness gene expression in the presence of TPP. Construction of biosensors containing 100~400 bp fragments of D8PYI contigs, and in vivo imaging using the biosensors displayed TPP-specific changes in the expression of a green fluorescence protein reporter. In this regard, the adaptation of in silico riboswitch screening from environmental metagenomes could provide biosensors for detection of specific metabolites.

This study was performed to investigate the nutrition knowledge, dietary attitudes, and dietary behaviors among high school students by gender. The subjects were 275 students (127 male, 148 female) in Incheon metropolitan area. Selfadministered questionnaires consisted of general characteristics and anthropometric data, nutrition knowledge, dietary attitudes, and dietary behaviors. The average score of nutrition knowledge was significantly higher in female subjects (9.4) compared to male subjects (8.2) (p<0.01). Male subjects had a higher score for dietary attitudes than female subjects (p<0.001). Frequency of meals was significantly higher in male subjects compared to female subjects (p<0.05). Duration of meal time in male subjects was significantly higher (‘5-10 minutes’) compared to female subjects (p<0.001). Unbalanced diet was significantly higher in female subjects (66.3%) compared to male subjects (48.9%) (p<0.01). Male subjects showed significantly higher consumption frequency of ‘dairy’ (p<0.001) and ‘beans’ (p<0.001) compared to female subjects. For snack consumption, male subjects showed higher consumption frequency of ‘nuts’ (p<0.001), ‘soda’ (p<0.05), ‘fast foods’ (p<0.001), and ‘ramyeon’ (p<0.01), but lower consumption frequency of ‘biscuits and bakery’ (p<0.01) compared to female subjects. Therefore, it is necessary to develop a systemic nutrition education program for high school students by gender.