The dependence of active-layer thickness on the power conversion efficiency (PCE) of inverted organic photovoltaics (OPVs) based on poly(3-hexylthiphene) and 6,6-phenyl-C61-butyric acid methyl ester ...was investigated. When PCEs were measured immediately after device fabrication, the optimum thickness was ~100 nm. It was, however, found that thick OPVs exhibit higher PCEs a few months later, whereas thin OPVs simply degraded with time. Consequently, the optimum thickness changed with time. Considering this fact, we discuss the relationship between the active-layer thickness and PCE.
The spectral evolution of the classical nova V2468 Cygni (Nova Cyg 2008) was monitored at Asiago Astrophysical Observatory in Italy and at Nishi-Harima Astronomical Observatory in Hyogo Japan from ...soon after the discovery in March 2008 to the end of 2009. The notable peculiarities in the spectra of this nova were the asymmetric and variable profiles of its emission lines. The emission-line profiles of H I varied in the early decline stage in 2008, while their profiles were nearly stable in 2009. On the other hand, large variations in the profiles of the emission lines of O III, Fe VII, and He II were observed in 2009. In the spectrum obtained on 2009 October 15, the red parts of the emission lines of O III strengthened with respect to the profiles in September, while the red parts of the lines of He II and Fe VII faded. The emission lines of Fe VII 5721 and Fe VII + Ca V 6087 exhibited convex profiles on 2009 September 27 and 28 in a similar way to the other lines, while only these lines had concave profiles on October 26 and 29. It seems to be difficult to explain the variations in the emission-line profiles with any known model of nova shells. The absolute magnitude at light maximum and the distance to the nova are estimated to be MV = −8.8 ± 0.3 mag and d = 5.5 ± 0.8 kpc. Using the intensities of H I, He I, and He II lines observed in September 2009, we estimated the helium abundance in number to be N(He) = 0.20 ± 0.01, and the mass of the ejecta to be 1.7 ± 1 × 10-5 M⊙. A very broad emission line from 3790 Å to 3850 Å was detected in the spectrum obtained on 2009 July 21. We propose that the multiple lines of Fe V 3F, 3839.3, 3794.9, 3851.3, 3819.9 etc. suddenly strengthened at that time, but the cause of this phenomenon is not known.
UX Orionis stars (UXors) are Herbig Ae/Be or T Tauri stars exhibiting sporadic occultation of stellar light by circumstellar dust. GM Cephei is such a UXor in the young (∼4 Myr) open cluster Trumpler ...37, showing prominent infrared excess, emission-line spectra, and flare activity. Our photometric monitoring (2008-2018) detects (1) an ∼3.43 day period, likely arising from rotational modulation by surface starspots, (2) sporadic brightening on timescales of days due to accretion, (3) irregular minor flux drops due to circumstellar dust extinction, and (4) major flux drops, each lasting for a couple of months with a recurrence time, though not exactly periodic, of about two years. The star experiences normal reddening by large grains, i.e., redder when dimmer, but exhibits an unusual "blueing" phenomenon in that the star turns blue near brightness minima. The maximum extinction during relatively short (lasting ≤50 days) events, is proportional to the duration, a consequence of varying clump sizes. For longer events, the extinction is independent of duration, suggestive of a transverse string distribution of clumps. Polarization monitoring indicates an optical polarization varying ∼3%-8%, with the level anticorrelated with the slow brightness change. Temporal variation of the unpolarized and polarized light sets constraints on the size and orbital distance of the circumstellar clumps in the interplay with the young star and scattering envelope. These transiting clumps are edge-on manifestations of the ring- or spiral-like structures found recently in young stars with imaging in infrared of scattered light, or in submillimeter of thermalized dust emission.
This study aimed to determine the demand of strength-power capabilities represented by traditional and ankle-specific vertical jump modalities ‑ squat jump (SJ), counter-movement jump (CMJ), ...rebound-continuous jump (RJ), rebound-continuous ankle jump (AJ) ‑ relative to sprint acceleration ability during the entire acceleration phase of maximal sprint.
Nineteen male sprinters performed a 60-m maximal sprint and various vertical jumps. Correlation coefficients among the vertical jump performances and between those and the 60-m sprint time and sprint acceleration at each step were calculated.
There were significant relationships between the 60-m sprint time and SJ height, CMJ height, AJ height, and AJ index. AJ height and index had no correlation with any other jump variables. Acceleration was significantly correlated with SJ height from the 6th to the 10th steps (r=0.48-0.51) and with CMJ height from the 5th to the 11th steps (r=0.46-0.54). Acceleration was also correlated with the AJ index from the 14th to the 19th steps (r=0.48-0.54). Acceleration had no correlation with the RJ index at any step.
The results suggest that the AJ allows assessment of different reactive strengths compared with traditional jump modalities. To accelerate effectively, the explosive strengths of the SJ and CMJ are important during the early stage of acceleration (from 6.6±0.4 to 17.5±0.8 m), and the reactive strength represented by the AJ is necessary during the later stage of acceleration (from 23.4±1.0 to 33.7±1.4 m). Sprinters and coaches should be aware of the different demands of strength-power capability for effective acceleration.
We present optical (B, V, Rc, Ic and y) and near-infrared (J, H, and Ks) photometric and spectroscopic observations of a classical nova V1280 Scorpii for five years from 2007 to 2011. Our photometric ...observations show a declining event in optical bands shortly after the maximum light, which took about 250 days to recover. This event was most probably caused by dust formation. The event was accompanied by a short (~30 days) re-brightening episode (~2.5 mag in V), which suggests that there had been some re-ignition of the surface nuclear burning. After 2008, the y band observations show a very long plateau at around y = 10.5 for more than 1000 days until April 2011 (~1500 days after the maximum light). The nova had taken a very long time (~50 months) to enter the nebular phase, according to a clear detection of both O iii 4959 and 5007 and is still continuing to generate the wind caused by H-burning. This finding suggests that historically V1280 Sco is evolving at its slowest ever measured rate. The interval from the maximum light (2007 February 16) to the beginning of the nebular phase is longer than any previously known slow novae: V723 Cas (18 months), RR Pic (10 months), or HR Del (8 months). It suggests that the mass of a white dwarf in the V1280 Sco system might be 0.6 M⊙ or lower. The distance, based on our measurements of the expansion velocity combined with the directly measured size of the dust shell, is estimated to be 1.1 ± 0.5 kpc.
The benefit of body weight resistance exercise with slow movement (BWRE-slow) for muscle function is well-documented, but not for energy metabolism. We aimed to examine physiological responses ...e.g., energy expenditure (EE), respiratory exchange ratio (RER), and blood lactate (La) during and after BWRE-slow compared to EE-matched treadmill walking (TW). Eight healthy young men (23.4 ± 1.8 years old, 171.2 ± 6.2 cm, 63.0 ± 4.8 kg) performed squat, push-up, lunge, heel-raise, hip-lift, and crunch exercises with BWRE-slow modality. Both the concentric and eccentric phases were set to 3 s. A total of three sets (10 repetitions) with 30 s rest between sets were performed for each exercise (26.5 min). On another day, subjects walked on a treadmill for 26.5 min during which EE during exercise was matched to that of BWRE-slow with the researcher controlling the treadmill speed manually. The time course changes of EE and RER were measured. The EE during exercise for BWRE-slow (92.6 ± 16.0 kcal for 26.5 min) was not significantly different from the EE during exercise for TW (95.5 ± 14.1 kcal, p = 0.36). BWRE-slow elicited greater recovery EE (40.55 ± 3.88 kcal for 30 min) than TW (37.61 ± 3.19 kcal, p = 0.029). RER was significantly higher in BWRE-slow during and 0-5 min after exercise, but became significantly lower during 25-30 min after exercise, suggesting greater lipid oxidation was induced about 30 min after exercise in BWRE-slow compared to TW. We also indicated that BWRE-slow has 3.1 metabolic equivalents in average, which is categorized as moderate-intensity physical activity.
Effect of fine water droplets on the laminar burning velocity of propane/air premixed flame was investigated by using a single jet-plate configuration. For the case without water droplets, the ...measured laminar burning velocities are in reasonably good agreement with previously reported data and the numerical simulation. The dependence of the burning velocity on the stretch rate for the case without water droplets is positive for all mixtures tested, resulting in the negative Markstein length, which coincides with previous experimental and theoretical studies. Water droplets lower significantly the laminar burning velocity and change its dependence on the stretch rate to negative. This leads to apparent positive Markstein lengths. The positive Markstein length was discussed on the basis of the droplets behavior in the stagnation flow field adopted in the present study. Even if the droplet mass loading was kept constant, the water droplets do not follow the diverting flow field when the stretch rate is high and the droplets accumulation occurs in the stagnation region where the burning velocities were measured. This fact results in the lower burning velocity as compared to that measured for uniformly dispersed water droplets.
► Burner with single jet-plate configuration gives correct unstretched laminar burning velocities. ► Water droplets cause a significant reduction of laminar burning velocity. ► Markstein number changes from negative to positive with water droplet addition. ► Droplet accumulation occurs in the stagnation region for high stretch rate. ► Droplet dynamics affects the extinguishment of flame by water droplets.
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