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Allrounder Strategy for Photopatterning Silver Nanowire Network Electrodes
No full textDespite their high optical transparency and electrical conductivity, the commercialization of silver nanowire materials as transparent electrodes is challenging owing to the lack of a scalable micropatterning process. This paper proposes a versatile method for photopatterning silver nanowire networks, based on photoinduced nanowire???nanowire and nanowire???substrate cross-linking. Because the proposed method requires only a small loading of the photocross-linking agent, the intrinsic physical characteristics of the silver nanowire network can be preserved. Furthermore, through the roughness-assisted wetting phenomenon, the resulting patterns can be selectively hybridized to form bilayered nanowire/conducting polymer electrodes. The resulting hybrid transparent electrodes exhibit a low roughness, excellent tolerance to oxidation or electrochemical processes, and mechanical stability against bending without compromising the excellent optical/electrical characteristics achievable from the pristine silver nanowire network. These benefits are integrated to assemble an active-matrix-driven electrochromic display. The proposed method can thus facilitate the practical application of silver nanowire network based transparent electrodes
Boosted Output Voltage of BiSbTe-Based Thermoelectric Generators via Coupled Effect between Thermoelectric Carriers and Triboelectric Charges
No full textThe present work demonstrates the very first approach to enhancing the output voltage of a thermoelectric generator by introducing highly charged polyimide-based dielectrics. High charge density over 320 mu C m(-2) in C-60-containing block polyimide (PI-b-C-60) having excellent charge retention characteristics is obtained through an ion injection process, attached at the cooling part of a thermoelectric generator consisting of Cu/p-type BiSbTe/Au/Cr/SiO2/Si. This significantly increases the electric potential difference across the thermoelectric generator (TEG) from 4.2 to 8.2 mV at the temperature difference of 20 K, and this increase can be maintained over 1 day. Density functional theory studies support that the enhancement depends on the dielectric constant and the insulating properties of the dielectric. Finally, a TEG consisting of 81 p-type BiSbTe legs with PI-b-C-60 generates an output voltage of 0.632 V, and the charged energy of the 10 mF-capacitor is boosted by 30 s. These results demonstrate the possibility of large-area TEG fabrication without the need for modification of the TE materials by introducing a new mechanism which is based on the coupling effect between thermoelectric carriers and triboelectric charges
Electronic Structure and Magnetocaloric Effect of Sr-Doped SmCoO3 Perovskites
No full textWe present a study on the magnetic and magnetocaloric characters of Sm1-xSrxCoO3 (x=0.4-0.6) synthesized by solid-state reactions. Recorded M(T) data at H=100 Oe show an increase of the Curie temperature (T-C) from 143 K for x=0.4 to 153 K for x=0.5, but a higher x value (x = 0.6) reduces T-C to similar to 92 K. A singularity region sandwiched between the Griffiths and pure paramagnetic phases has been observed in x=0.4, but it becomes invisible at x=0.5 and 0.6. These properties are assigned to a competition between ferromagnetic and anti-ferromagnetic interactions induced by Co3+ and Co4+ ions. The Co3+/Co4+ mixed valence has been confirmed upon the analysis of Co K-edge x-ray absorption spectra. Using Maxwell's relations and M(H) data, we have calculated the absolute magnetic entropy change (vertical bar Delta S-m vertical bar). Around T-C, the maximum magnetic entropy changes (vertical bar Delta S-max vertical bar) of x=0.4, 0.5 and 0.6 are about 1.19, 1.22 and 0.81 J/kg K for H =50 kOe, respectively. The values of the relative cooling power are in the range of 58 - 93 J/kg. Our analyses also indicate all vertical bar Delta S-m (T, H)vertical bar data obeying the universal master curve as constructing the vertical bar Delta S-m vertical bar/vertical bar Delta S-max vertical bar vs. theta plots, where theta is defined as the reduced temperature. When considering exponential parameters N(T, H) and n associated with vertical bar Delta S-m(T, H)vertical bar and vertical bar Delta S-max(H)vertical bar, respectively, we have found their values are different from the mean-field theory value n = 2/3. These results prove the Sm1-xSrxCoO3 samples have the second-order nature and short-range magnetic order
The Temporal Bias Approach to the Symmetry Problem and Historical Closeness
No full textIn addressing the Lucretian symmetry problem, the temporal bias approach claims that death is bad because it deprives us of something about which it is rational to care (e.g., future pleasures), whereas prenatal nonexistence is not bad because it only deprives us of something about which it is rational to remain indifferent (e.g., past pleasures). In a recent contribution to the debate on this approach, Miguel and Santos argue that a late beginning can deprive us of a future pleasure. Their argument is based on the claim that for birth or death to deprive a person of any value in life, the historically closest counterfactual situation that contains the value is such that the person begins to exist earlier or dies later. This is what they call the Historical Condition. However, the Historical Condition is untenable for several reasons. First, this condition substantially weakens the explanatory capacity of the deprivation account because it implies that most ordinary sorts of pleasures are not deprived by death. In addition, the Historical Condition is vulnerable to counterexamples. In particular, what they offer as a standard case of the deprivation of future pleasure due to a late beginning (what they call Seeing The Beatles), or some of its variants, can be used to falsify this condition. Finally, the Historical Condition is theoretically indefensible because it is based on a faulty analysis of deprivation
Time delay estimation of traffic congestion propagation due to accidents based on statistical causality
Get PDFThe accurate estimation of time delays is crucial in traffic congestion analysis, as this in-formation can be used to address fundamental questions regarding the origin and propagation of traffic congestion. However, the exact measurement of time delays during congestion remains a challenge owing to the complex propagation process between roads and high uncertainty regarding future behav-ior. To overcome this challenge, we propose a novel time delay estimation method for the propagation of traffic congestion due to accidents using lag-specific transfer entropy (TE). The proposed method adopts Markov bootstrap techniques to quantify uncertainty in the time delay estimator. To the best of our knowledge, our proposed method is the first to estimate time delays based on causal relationships between adjacent roads. We validated the method's efficacy using simulated data, as well as real user trajectory data obtained from a major GPS navigation system in South Korea
A Kinetic Indicator of Ultrafast Nickel-Rich Layered Oxide Cathodes
No full textElucidating high-rate cycling-induced nonequilibriumelectrodereactions is crucial for developing extreme fast charging (XFC) batteries.Herein, we unveiled the distinct rate capabilities of a series ofNi-rich layered oxide (NRLO) cathodes by quantitatively establishingtheir dynamic structure-kinetics relationships. Contrary toconventional views, we discovered electrode kinetic properties obtained ex-situ near equilibrium states failed to assess the effectiverate capability of NRLOs at ultrafast C rates. Further, the kineticphase heterogeneity, characterized by the dynamic separations in in-situ X-ray diffraction patterns and deviations in NRLO c-axis lattice parameters, exclusively correlated with thecapacity reduction under XFC and became an effective indicator ofthe NRLO rate capability. Enhancing the cycling temperature boostedthe rate capability of studied NRLOs by similar to 10%, which was furtherverified to mitigate the kinetic phase heterogeneity during XFC. Overall,this study lays the groundwork for tuning the kinetic phase heterogeneityof electrodes to develop ultrafast batteries
Examination of sulfate resistance of nano-alumina added ordinary Portland cement paste, focusing on the two different crystallinity of nano-aluminas
No full textThis study examined the influence of the crystallinity of added nano-alumina on the sulfate resistance of ordinary Portland cement (OPC) paste. Two crystalline types of nano-aluminas (a-and ?-phase) were incorporated in cement pastes, which were exposed to sulfate solution. In the results, both paste samples having a- and ?-phase aluminas had accelerated compressive strength loss and increased length expansion compared to the sample without alumina addition. In particular, the rapidly decreased dynamic elastic modulus of the nano-alumina added samples postulates the greatly increased internal stress likely by the increased formation of volume expansive reaction products, such as ettringite, which was supported by the XRD and TG results. The greater ettringite formation in the nano-alumina added samples was likely due to reactive AH(3) (=Al(OH)(3)) gel formation as the higher consumption degree of portlandite in the alumina added samples indirectly indicates the active AH(3) gel formation, resulting in additional ettringite formation from the reaction of AH(3) with Na2SO4 solution. A further degree of sulfate attack was observed in the ?-alumina added sample for the long-term Na2SO4 exposure (180 days) mainly due to the greater degree of gypsum formation inducing more internal expansive stress compared to the a-alumina added sample
Fully inkjet-printed large-scale photoelectrodes
No full textSmall-area photoelectrodes are used to study fundamental science and material development for photoelectrochemical (PEC) water splitting cells at the laboratory scale. For practical applications, however, one needs to develop scalable geometrical designs and architectures of large photoelectrodes as well as their fabrication using low-cost, solution-processed, scalable methods. In this perspective, we first discuss the device physics concepts for devel-oping large photoelectrodes using dimensional engineering (size, geometry, shape, and structures) and scalable architectures (such as symmetric and asymmetric designs with gridlines as well as mono-lithically integrated modules with interconnections), similar to the earlier development of large thin-film photovoltaic cells. Finally, we propose a novel and strategic protocol to fabricate these designs for the development of large-photoelectrode modules via commercially deployable, fully inkjet-printing as a solution pro-cessed thin-film deposition method
Electron-Ion Temperature Ratio in Astrophysical Shocks
No full textCollisionless shock waves in supernova remnants and the solar wind heat electrons less effectively than they heat ions, as is predicted by kinetic simulations. However, the values of T ( e )/T ( p ) inferred from the H alpha profiles of supernova remnant shocks behave differently as a function of Mach number or Alfven Mach number than what is measured in the solar wind or predicted by simulations. Here we determine T ( e )/T ( p ) for supernova remnant shocks using H alpha profiles, shock speeds from proper motions, and electron temperatures from X-ray spectra. We also improve the estimates of sound speed and Alfven speed used to determine Mach numbers. We find that the H alpha determinations are robust and that the discrepancies among supernova remnant shocks, solar wind shocks, and computer-simulated shocks remain. We discuss some possible contributing factors, including shock precursors, turbulence, and varying preshock conditions
