• Transactions on Electrical and Electronic Materials
• /
• v.7 no.1
• /
• pp.12-15
• /
• 2006

We present the structural, magnetic, and electrical properties in the (Al,Mn)N films with various Mn concentrations grown by plasma-enhanced molecular beam epitaxy. X-ray diffraction analyses reveal that the (Al,Mn)N films have the wurtzite structure without secondary phases. All (Al,Mn)N films showed the ferromagnetic ordering. Particularly, ($Al_{1-x}Mn_{x}$)N film with x = 0.028 exhibited the highest magnetic moment per Mn atom at room temperature. Since all the films exhibit the insulating characteristics, the origin of ferromagnetism in (Al,Mn)N might be attributed to either indirect exchange interaction caused by virtual electron excitations from Mn acceptor level to the valence band within the samples or a percolation of bound magnetic polarons arisen from exchange interaction of localized carriers with magnetic impurities in a low carrier density regime.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.921-924
• /
• 2006

In an attempt to enhance secondary electron emission characteristics of PDP, $12CaO{\cdot}7Al_2O_3$ electride was used as electron emission layer of PDP discharge cells. The compound was synthesized by Ca-treatment and its electron emission behavior during the glow discharge was measured. The results indicated that the spayed electride reduces the discharge voltage by ${\sim}20$ volts and decrease the discharge delay by more than 70%.

• Tunnel and Underground Space
• /
• v.6 no.3
• /
• pp.260-266
• /
• 1996

Safety concern is one of the most important parameters in the design of explosive building demolition. Laboratory experiments were performed to investigate the failure behaviour of concrete columns and the effects of protection materials. Fourteen reinforced columns with two sizes were constructed and the effects of protection materials were tested for two kinds of materials: non woven fabrics and wire net. The results showed that control of gas effects is a key to the control of flying chips. It was recommended to use both wire net and non woven fabrics as primary and secondary protection materials. Such protection method was successfully applied to the explosive demolition of 16 and 17-strory apartment buildings.and the results of a simulation on a model tunneling workings using diesel equipments are introduced. In case of typical model of tunneling face, the gas concentration of human height is about one third of roof concentration and right side half of the tunnel shows better environment than left half. NOx concentration of workings can be estimated about 0.45ppm which is much lower than permissible level(5 ppm).

• Economic and Environmental Geology
• /
• v.55 no.6
• /
• pp.661-669
• /
• 2022

The need for miniaturization, high efficiency, and green energy resources as an energy storage device through the development of various electronic device has emerged. Accordingly, nanomaterials with excellent electrochemical properties, such as graphene and graphene hybrids, are attracting attention as promising materials. In particular, in the electric vehicle industry, cost reduction of secondary batteries is a key factor that can determine the spread of related industries, and it is most important to analyze R&D trends for battery material technology and respond to future technological development directions. Therefore, in this study, we tried to suggest a direction for R&D activities in the future by analyzing patent trends for graphene anode material technology for secondary batteries and deriving implications. As a result, in the case of anode material technology, the proportion of foreigners in the US and European patent markets was higher than in the Korean and Japanese patent markets, which means that the US and European marketability is high. In addition, Japanese applicants are filing high-level applications not only in the Japanese patent market but also in other countries suggests that Japan is leading the technology in this field. Lastly, the proportion of research institutes in the patent market of Korea and the US remains high compared to that of Japan and Europe, indicating that the commercialization of technology is still slow in those countries. Therefore research institutes and companies in Korea will have to establish their own strategies for developing and securing materials using the results of patent trends in major countries and major companies analyzed in this study.

• Proceedings of the KWS Conference
• /
• 2008.05a
• /
• pp.10-10
• /
• 2008

• 한국전기화학회:학술대회논문집
• /
• 2001.10a
• /
• pp.33-33
• /
• 2001

• Proceedings of the Korean Ceranic Society Conference
• /
• 2003.10a
• /
• pp.93.2-93
• /
• 2003

• Journal of the Korean Electrochemical Society
• /
• v.5 no.1
• /
• pp.30-38
• /
• 2002

Disordered carbon and boron-substituted disordered carbons $C_{l-x}B_x(x=0.05,\;0.10,\;0.20)$ were synthesized by Pyrolysis of LPG(liquid Propane gas)and $BCl_3$. Their electrochemical properties as anode materials for Li-ion secondary batteries were then investigated. When PVDF is added to the sample in a weight ratio 5 : 95, the disordered carbon with x=0.00 had the first discharge capacity 374 mAh/g. Its cycling performance was relatively good from the second cycle and it had the discharge capacity 258 mAh/g at the 10th cycle. When PVDF is added to the sample in a weight ratio 5 : 95, the sample with x=0.05 among the samples $C_{l-x}B_x(x=0.05,\;0.10,\;0.20)$ exhibited the largest first discharge capacity 860 mAh/g and discharge capacity 181 mAh/g at the 10th cycle. All the samples had similar cycling performances from the second cycle. The sample $C_{0.90}B_{0.10}$ showed the best electrochemical properties as a anode materials fur Li-ion secondary battery from the view points of the first discharge capacity(853 mAh/g when $10w1.\%$ PVDF is used), cycling performance, discharge capacity(400mAh/g at the 10th cycle when $10wt.\%$ PVDF is used). All the samples showed generally larger charge and discharge capacities when $10wt.\%$ PVDF ratter than $5wt.\%$ PVDF is used. The plateau region in the range of voltage lower than 1.25V becomes larger probably since the structure becomes less disordered by the addition of boron. When boron is added, the charge and discharge capacities decreased suddenly at the second cycle. This may be become only a part of Li are reversibly deintercalated and intercalated and a part of Li which are strongly combined with B are not deintercalated. The increases in charge and discharge capacities are considered to be resulted from the increase in the potential of Li in the boron-added carbons, caused by the strengthening of the chemical bond between the intercalated Li and the boron-carbon host since the boron acts as electron acceptor.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.16
• /
• pp.7123-7127
• /
• 2015

Purpose: To determine the utility of secondary circulating prostate cells for predicting early biochemical failure after radical prostatectomy for prostate cancer and compare the results with the Walz nomagram. Materials and Methods: A single centre, prospective study of men with prostate cancer treated with radical prostatectomy between 2004 and 2014 was conducted, with registration of clinical-pathological details, total serum PSA pre-surgery, Gleason score, extracapsular extension, positive surgical margins, infiltration of lymph nodes, seminal vesicles and pathological stage. Secondary circulating prostate cells were obtained using differential gel centrifugation and assessed using standard immunocytochemistry with anti-PSA. Biochemical failure was defined as a PSA >0.2ng/ml, predictive values werecalculated using the Walz nomagram and CPC detection. Results: A total of 326 men participated, with a median follow up of 5 years; 64 had biochemical failure within two years. Extracapsular extension, positive surgical margins, pathological stage, Gleason score ${\geq}8$, infiltration of seminal vesicles and lymph nodes were all associated with higher risk of biochemical failure. The discriminative value for the nomogram and circulating prostate cells was high (AUC >0.80), predictive values were higher for circulating prostate cell detection, with a negative predictive value of 99%, sensitivity of 96% and specificity of 75%. Conclusions: The nomagram had good predictive power to identify men with a high risk of biochemical failure within two years. The presence of circulating prostate cells had the same predictive power, with a higher sensitivity and negative predictive value. The presence of secondary circulating prostate cells identifies a group of men with a high risk of early biochemical failure. Those negative for secondary CPCs have a very low risk of early biochemical failure.

• Radiation Oncology Journal
• /
• v.35 no.1
• /
• pp.78-89
• /
• 2017

Purpose: To determine the optimal radiotherapy technique for gastric mucosa-associated lymphoid tissue lymphoma (MALToma), we compared the dosimetric parameters and the risk of solid secondary cancer from scattered doses among anterior-posterior/ posterior-anterior parallel-opposed fields (AP/PA), anterior, posterior, right, and left lateral fields (4_field), 3-dimensional conformal radiotherapy (3D-CRT) using noncoplanar beams, and intensity-modulated radiotherapy composed of 7 coplanar beams (IMRT_co) and 7 coplanar and noncoplanar beams (IMRT_non). Materials and Methods: We retrospectively generated 5 planning techniques for 5 patients with gastric MALToma. Homogeneity index (HI), conformity index (CI), and mean doses of the kidney and liver were calculated from the dose-volume histograms. Applied the Biological Effects of Ionizing Radiation VII report to scattered doses, the lifetime attributable risk (LAR) was calculated to estimate the risk of solid secondary cancer. Results: The best value of CI was obtained with IMRT, although the HI varied among patients. The mean kidney dose was the highest with AP/PA, followed by 4_field, 3D-CRT, IMRT_co, and IMRT_non. On the other hand, the mean liver dose was the highest with 4_field and the lowest with AP/PA. Compared with 4_field, the LAR for 3D-CRT decreased except the lungs, and the LAR for IMRT_co and IMRT_non increased except the lungs. However, the absolute differences were much lower than <1%. Conclusion: Tailored RT techniques seem to be beneficial because it could achieve adjacent organ sparing with very small and clinically irrelevant increase of secondary solid cancer risk compared to the conventional techniques.