Organo-halide perovskite solar cells (PSCs) are lightweight and low cost, and they offer high power conversion efficiencies. PSCs have proven to be useful in terrestrial applications. In addition, ...they are particularly attractive for space applications because they can offer a higher radiation tolerance than GaAs and Si solar cells. This paper evaluates the damage coefficient for minority-carrier diffusion length K L of perovskite crystals after 1 MeV electron irradiation by time-resolved photoluminescence measurements to investigate the reason for their high radiation tolerance. Results show that perovskite crystals have a lower damage coefficient K L than that of InP crystals with a high radiation tolerance. On the other hand, first-principles calculations indicate that the displacement energy of perovskite crystals is as low as that of Si, which does not have a high radiation tolerance. The present results suggest that the annealing effect occurs for PSCs at room temperature.
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IJS, KILJ, NUK, PNG, UL, UM
Aim: The effect of nitroglycerin on proper arterial stiffness of the arterial tree has not been fully clarified. The cardio-ankle vascular index (CAVI), which is an application of the stiffness ...parameter β theory on the arterial tree from the origin of the aorta to the ankle, was developed recently. Furthermore, the stiffness of the aorta (heart-thigh β (htBeta)) and of the femoral-tibial arteries (thigh to ankle β (taBeta)) could be monitored by applying the same theory. The effects of nitroglycerin on CAVI, htBeta, and taBeta were studied comparing the values of healthy people and those of arteriosclerotic patients.Methods: The subjects were healthy people (CAVI ＜7.5, n=25) and arteriosclerotic patients (CAVI ＞9, n=25). Nitroglycerin (0.3 mg) was administrated sublingually, and various arterial stiffness indices were measured at one-minute intervals for a period of 20 minutes using Vasera VS-1500 (Fukuda Denshi, Tokyo).Results: After the administration of nitroglycerin in healthy people, CAVI decreased significantly after 5 min. from 6.76(6.32-7.27) to 5.50(4.70-6.21), P＜0.05, and recovered after 15 min. htBeta from 5.10(4.76-5.76) to 3.96(3.35-4.79), P＜0.05, and taBeta from 14.41(10.80-16.33) to 10.72 (9.19-13.01), P＜0.05 also decreased significantly. In arteriosclerotic patients, CAVI decreased after 5 min. from 10.47(9.67-11.29) to 9.71(8.74-10.57), P＜0.05 and recovered after 15 min. htBeta did not significantly change from 12.00(11.46-13.21) to 11.81(10.14-13.83), ns, but taBeta decreased significantly from 18.55(12.93-23.42) to 12.37(9.68-16.99), P＜0.05.Conclusion: These results indicate that a nitroglycerin-induced decrease of arterial stiffness is more prominent in muscular arteries than in elastic arteries, and this effect was preserved much more prominently in arteriosclerotic patients than in healthy people.
Developing self-organised swarm systems capable of adapting to environmental changes as well as to dynamic situations is a complex challenge. An efficient labour division model, with the ability to ...regulate the distribution of work among swarm robots, is an important element of this kind of system. This paper extends the popular response threshold model and proposes a new adaptive response threshold model (ARTM). Experiments were carried out in simulation and in real-robot scenarios with the aim of studying the performance of this new adaptive model. Results presented in this paper verify that the extended approach improves on the adaptability of previous systems. For example, by reducing collision duration among robots in foraging missions, our approach helps small swarms of robots to adapt more efficiently to changing environments, thus increasing their self-sustainability (survival rate). Finally, we propose a minimal version of ARTM, which is derived from the conclusions drawn through real-robot and simulation results.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Designing new materials with desired properties is a complex and time-consuming process. One of the most challenging factors of the design process is the huge search space of possible materials. ...Machine learning methods such as Formula: see text-nearest neighbors, support vector machine (SVM) and artificial neural network (ANN) can contribute to this process by predicting materials properties accurately. Properties of multi-principal element alloys (MPEAs) highly depend on alloys’ phase. Thus, accurate prediction of the alloy’s phase is important to narrow down the search space. In this paper, we propose a solution of employing SVM method with hyperparameters tuning and the use of weighted values for prediction of the alloy’s phase. Using the dataset consisting of the experimental results of 118 MPEAs, our solution achieves a cross-validation accuracy of 90.2%. We confirm the superiority of this score over the performance of ANN statistically. On the other dataset containing 401 MPEAs, our SVM model is comparable to ANN and exhibits 70.6% cross-validation accuracy. We also found that additional variables, including average melting temperature and standard deviation of melting temperature, increase prediction accuracy by 3.34% in the best case.
XANES and ELNES in Ceramic Science Tanaka, Isao; Mizoguchi, Teruyasu; Yamamoto, Tomoyuki
Journal of the American Ceramic Society,
August 2005, Volume:
88, Issue:
8
Journal Article
Peer reviewed
Both X‐ray absorption near edge structures (XANES) and electron energy loss near edge structure (ELNES) are important tools in ceramic science offering information on local environment of selected ...elements not only in crystals but also in amorphous materials. Recent technological progress enables measurements of XANES of ppm‐level dopants using modern synchrotron facilities. Combined with transmission electron microscopy, ELNES can be used to analyze the local structures with subnanometer spatial resolution. First principles methods to reproduce and interpret the spectra have been established just recently. When a core‐hole is adequately taken into account, most of K‐edge spectra can be well reproduced using a modern band‐structure method within one‐electron approximation. The same is true for L2, 3‐edge spectra of non‐transition metal compounds. However, multi‐electron calculations are mandatory to reproduce L2, 3‐edge spectra of 3d transition‐metal elements because of strong electronic correlations. In this paper, some recent results obtained in our group by the combination of XANES/ELNES experiments and theoretical calculations are reviewed.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
Isostatic pressure effects on the elastic and electronic properties of non-doped and Mn4+-doped K2SiF6 (KSF) have been investigated by first-principles calculations within density functional theory ...(DFT). Bulk modulus was obtained by the Murnaghan’s equation of states (EOS) using the relationship between volume and pressures at pressures between 0 and 40 GPa, and elastic constants were calculated by the stress–strain relationship giving small distortions at each pressure point. The other elastic parameters such as shear modulus, sound velocity and Debye temperature, which can be obtained from the elastic constants, were also estimated. The influence of external isostatic pressure on the electronic properties, such as crystal field strength 10Dq and emission energy of 2E → 4A2 transition (Eem), of KSF:Mn4+ was also studied. The results suggest that 10Dq and Eem linearly increase and decrease, respectively, with increasing pressure.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Optically active narrow-bandgap polymers ((R,R)- and (S,S)-PTB5) consisting of alternating n-octyl thieno3,4-bthiophene-2-carboxylate and benzo1,2-b:4,5-b′dithiophene units bearing optically pure ...(R)- and (S)-2-ethylhexyl pendants, respectively, were synthesized for the first time. (R,R)- and (S,S)-PTB5 films showed apparent circular dichroism in their absorption regions of the polymer backbone due to the formation of a chirally ordered superstructure induced by the chirality of the branched alkyl pendants. Inverted-type bulk heterojunction polymer solar cells (PSCs) were fabricated using (R,R)- or (S,S)-PTB5 as electron donors and 6,6-phenyl-C61-butyric acid methyl ester as an electron acceptor. The photovoltaic properties of the PSCs were compared with those of the corresponding PSC containing optically inactive PTB5 bearing racemic 2-ethylhexyl pendants.
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•Development of novel thienothiophene–benzodithiophene-based donor polymers.•Chirality control of 2-ethylhexyl pendants in donor polymers.•Application of optically active donor polymers to bulk heterojunction polymer solar cells.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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![Thieno[3,4-b]thiophene–benz...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/0032-3861/small "Thieno[3,4-b]thiophene–benzo[1,2-b:4,5-b′]dithiophene-based polymers bearing optically pure 2-ethylhexyl pendants: Synthesis and application in polymer solar cells")
