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Nitrogen-doped hierarchical porous carbon (NHPC) materials were synthesized by using a chitosan/ polyethylene glycol (PEG) blend as raw material through a facile carbonization-activation process. In this method, chitosan was used as a nitrogen-containing carbon precursor, low cost and large-scale commercial PEG was employed as a porogen. The physical and electrochemical properties of the resultant NHPC were affected by the ratio of chitosan and PEG. The sample obtained by the ratio of 3 : 2 exhibits a high specific surface area (2269 m 2 g À1 ), moderate nitrogen doping (3.22 at%) and optimized pore structure. It exhibits a high specific capacitance of 356 F g À1 in 1 M H 2 SO 4 and 271 F g À1 in 2 M KOH at a current density of 1 A g À1 , and over 230 F g À1 can be still retained at a high current density of 20 A g À1 in both electrolytes. Additionally, the assembled symmetric supercapacitors show an excellent cycling stability with 94% (in 1 M H 2 SO 4 ) and 97% (in 2 M KOH) retention after 10 000 cycles at 1 A g À1 . These results indicate that the chitosan/PEG blend can act as a novel and appropriate precursor to prepare low-cost NHPC materials for high-performance supercapacitors.

We present a comprehensive understanding of the nonlinear absorption characteristics of CdSe-based nanoplatelets (NPLs) synthesized by the solution-phase method and the colloidal atomic layer deposition approach through Z-scan techniques at 532 nm with picosecond pulses. The CdSe NPLs exhibit strong two-photon induced free carrier absorption (effective three-photon absorption) upon the nonresonant excitation, resulting in a remarkable optical limiting behavior with the limiting threshold of approximately 75 GW/cm2. A nonlinear optical switching from saturable absorption (SA) to reverse saturable absorption (RSA) with increasing the laser intensity is observed when coating CdSe NPLs with a monolayer of CdS shell to realize the resonant absorption. The SA behavior originates from the ground state bleaching and the RSA behavior is attributed to the free carrier absorption. These findings explicitly demonstrate the potential applications of CdSe-based NPLs in nonlinear optoelectronics such as optical limiting devices, optical pulse compressors and optical switching devices.

In this article, a spectrophotometric color matching algorithm based on Stearns-Noechel model is proposed. This algorithm was run to predict recipes for 48 viscose blends. Color differences between the original blend samples and the calculated were expressed in CIE-LAB units (108standard observer). M (the empirical constant in Stearns-Noechel model) value was determined by median analysis. When M equals to 0.09, the best fit was obtained for three-components fiber blends. In that case, the maximum color difference is 1.22 CIELAB units and the average computed color difference is 0.56 CIELAB units for 36 three-components fiber blends under D65 illuminant. When M is from 0.03 to 0.06, the best fit was obtained for four-components fiber blends. In that case, the maximum color difference is 4.48 CIELAB units and the average computed color difference is 1.02 CIELAB units for 12 four-components fiber blends under D65 illuminant. It is demonstrated that the algorithm can be used in color matching of fiber blends.