FAMn:PbI<sub>3</sub> perovskite films were synthesized and probed mainly through electron spin resonance (ESR) spectroscopy. FAMn:PbI<sub>3</sub> with low (~1%) Mn concentration showed a hyperf...FAMn:PbI<sub>3</sub> perovskite films were synthesized and probed mainly through electron spin resonance (ESR) spectroscopy. FAMn:PbI<sub>3</sub> with low (~1%) Mn concentration showed a hyperfine sextet line originated from Mn<sup>++</sup> ions. FAMn:PbI<sub>3</sub> with high (10%) Mn concentration showed broad resonance (~500 G peak-to-peak linewidth). However, after bombardment of FAMn:PbI<sub>3</sub> with high Mn concentration by focused ion beams (FIB), a sharp ESR peak appeared. The peak-to-peak linewidth (ΔH<sub>pp</sub>) was ~8 G regardless of the temperature. The FIB-induced defect showed Curie behavior at low temperatures (5 K - 50 K), which indicates the presence of localized electrons at the defect sites at low temperatures. The g-value increased from g = 2.0002 to 2.0016 as the temperature increased from 5 K to 50 K. Together with the ongoing search for electron spin echo (ESE), this could potentially provide a platform for realizing magnetic bits, information storage, and increased manipulation speed.展开更多
The enduring discussion,why plants produce secondary metabolites with pharmacologically and toxicologically active towards mammals traces back to the eminent role of medicinal plants in the millennia-old history of ma...The enduring discussion,why plants produce secondary metabolites with pharmacologically and toxicologically active towards mammals traces back to the eminent role of medicinal plants in the millennia-old history of manhood.In recent years,the concept of an animal plant warfare emerged,which focused on the co-evolution between plants and herbivores.As a reaction to herbivory,plants developed mechanical defenses such as thorns and hard shells,which paved the way for adapted animal physiques.Plants evolved further defense systems by producing chemicals that exert toxic effects on the animals that ingest them.As a result of this selective pressure,animals developed special enzymes,e.g.cytochrome P450 monooxigenases(CYP450)that metabolize xenobiotic phytochemicals.As a next step in the evolutionary competition between plants and animals,plants evolved to produce non-toxic pro-drugs,which become toxic only after ingestion by animals through metabolization by enzymes such as CYP450.Because these sequestered evolutionary developments call to mind an arms race,the term animal plant warfare has been coined.The evolutionary competition between plants and animals may help to better understand the modes of action of medicinal plants and to foster the efficient and safe use of phytotherapy nowadays.展开更多
Missing values occur in bio-signal processing for various reasons,including technical problems or biological char-acteristics.These missing values are then either simply excluded or substituted with estimated values f...Missing values occur in bio-signal processing for various reasons,including technical problems or biological char-acteristics.These missing values are then either simply excluded or substituted with estimated values for further processing.When the missing signal values are estimated for electroencephalography (EEG) signals,an example where electrical signals arrive quickly and successively,rapid processing of high-speed data is required for immediate decision making.In this study,we propose an incremental expectation maximization principal component analysis (iEMPCA) method that automatically estimates missing values from multivariable EEG time series data without requiring a whole and complete data set.The proposed method solves the problem of a biased model,which inevitably results from simply removing incomplete data rather than estimating them,and thus reduces the loss of information by incorporating missing values in real time.By using an incremental approach,the proposed method alsominimizes memory usage and processing time of continuously arriving data.Experimental results show that the proposed method assigns more accurate missing values than previous methods.展开更多
文摘FAMn:PbI<sub>3</sub> perovskite films were synthesized and probed mainly through electron spin resonance (ESR) spectroscopy. FAMn:PbI<sub>3</sub> with low (~1%) Mn concentration showed a hyperfine sextet line originated from Mn<sup>++</sup> ions. FAMn:PbI<sub>3</sub> with high (10%) Mn concentration showed broad resonance (~500 G peak-to-peak linewidth). However, after bombardment of FAMn:PbI<sub>3</sub> with high Mn concentration by focused ion beams (FIB), a sharp ESR peak appeared. The peak-to-peak linewidth (ΔH<sub>pp</sub>) was ~8 G regardless of the temperature. The FIB-induced defect showed Curie behavior at low temperatures (5 K - 50 K), which indicates the presence of localized electrons at the defect sites at low temperatures. The g-value increased from g = 2.0002 to 2.0016 as the temperature increased from 5 K to 50 K. Together with the ongoing search for electron spin echo (ESE), this could potentially provide a platform for realizing magnetic bits, information storage, and increased manipulation speed.
文摘The enduring discussion,why plants produce secondary metabolites with pharmacologically and toxicologically active towards mammals traces back to the eminent role of medicinal plants in the millennia-old history of manhood.In recent years,the concept of an animal plant warfare emerged,which focused on the co-evolution between plants and herbivores.As a reaction to herbivory,plants developed mechanical defenses such as thorns and hard shells,which paved the way for adapted animal physiques.Plants evolved further defense systems by producing chemicals that exert toxic effects on the animals that ingest them.As a result of this selective pressure,animals developed special enzymes,e.g.cytochrome P450 monooxigenases(CYP450)that metabolize xenobiotic phytochemicals.As a next step in the evolutionary competition between plants and animals,plants evolved to produce non-toxic pro-drugs,which become toxic only after ingestion by animals through metabolization by enzymes such as CYP450.Because these sequestered evolutionary developments call to mind an arms race,the term animal plant warfare has been coined.The evolutionary competition between plants and animals may help to better understand the modes of action of medicinal plants and to foster the efficient and safe use of phytotherapy nowadays.
基金supported by the Ministry of Knowledge Economy,Korea, under the Information Technology Research Center support program supervised by National IT Industry Promotion Agency (No.NIPA-2011-C1090-1111-0008)the Special Research Program of Chonnam National University,2009the LG Yonam Culture Foundation
文摘Missing values occur in bio-signal processing for various reasons,including technical problems or biological char-acteristics.These missing values are then either simply excluded or substituted with estimated values for further processing.When the missing signal values are estimated for electroencephalography (EEG) signals,an example where electrical signals arrive quickly and successively,rapid processing of high-speed data is required for immediate decision making.In this study,we propose an incremental expectation maximization principal component analysis (iEMPCA) method that automatically estimates missing values from multivariable EEG time series data without requiring a whole and complete data set.The proposed method solves the problem of a biased model,which inevitably results from simply removing incomplete data rather than estimating them,and thus reduces the loss of information by incorporating missing values in real time.By using an incremental approach,the proposed method alsominimizes memory usage and processing time of continuously arriving data.Experimental results show that the proposed method assigns more accurate missing values than previous methods.