Real-Time Extension of TAO-DFT.

Thermally assisted occupation density functional theory (TAO-DFT) has been an efficient electronic structure method for studying the ground-state properties of large electronic systems with multi-reference character over the past few years. To explore the time-dependent (TD) properties of electronic systems (e.g., subject to an intense laser pulse), in this work, we propose a real-time (RT) extension of TAO-DFT, denoted as RT-TAO-DFT. Moreover, we employ RT-TAO-DFT to study the high-order harmonic generation (HHG) spectra and related TD properties of molecular hydrogen H2 at the equilibrium and stretched geometries, aligned along the polarization of an intense linearly polarized laser pulse. The TD properties obtained with RT-TAO-DFT are compared with those obtained with the widely used time-dependent Kohn-Sham (TDKS) method. In addition, issues related to the possible spin-symmetry breaking effects in the TD properties are discussed.

In situ real-time dataset as compared to the predicted thermal wheel performance of an energy recovery system.

The data article refers to in situ real-time dataset of a rotary desiccant wheel system and description of its experimental design. The original research paper was published in Heliyon, "Optimization of a rotary desiccant wheel for enthalpy recovery of air-conditioning in a humid hospitality environment" [1]. Supplementing to this data article are eight dataset files pertaining to ambient conditions and dehumidified process air outputs, as well as comparisons of experimental and numerical outputs under various operating conditions. Physical implementation of the experiments for numerical validation of transient responses included step changes to the regeneration air temperature, wheel speed, and airflow rate (i.e. fan speed). Finally, the data article provides insights to optimal performance of thermal wheel operation for HVAC practitioners and academic researchers.

Optimization of a rotary desiccant wheel for enthalpy recovery of air-conditioning in a humid hospitality environment.

Excessive condensation on cooling coils can be costly energy-wise due to humid process air streams. An innovative desiccant cooling system is introduced into an existing hotel in Taoyuan, Taiwan, where the ambient is humid year-round. Rejected heat from the existing cooling system is used as the energy source to heat the regeneration airstream for dehumidification of the process airstream via a rotary desiccant wheel. The paper develops and validates a numerical model for the heat and mass (moisture) transfer of the rotary desiccant wheel. The validated numerical model is used to simulate the expected performance of the rotary wheel under various conditions and operating strategies. The desiccant wheel's performance includes the steady-state moisture removal capacity (MRC) and the transient response time to reach steady-state. The examined factors include the ambient temperature and humidity, air flow rate, rotational speed of the wheel, wheel-split, and regeneration airstream temperature. From the simulation results, the paper offers the optimized control strategies for the operation of the rotary desiccant wheel system in the hotel.

Flexible solid-like electrolytes with ultrahigh conductivity and their applications in all-solid-state supercapacitors.

All-solid-state supercapacitors (ASSS) with solid-state electrolytes (SSEs) can be used to overcome the liquid leakage problem in devices. However, ionic conduction in solid electrolytes is one of the barriers to further improvements in ASSS. This paper describes the fabrication of a flexible SSE composed of poly(vinylidene fluoride-co-hexafluoropropylene), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, and ethylene carbonate, which demonstrates an ultrahigh conductivity of 8.52 mS cm-1 and a wide 5 V operation voltage window of -2 to +3 V. Electrodes composed of active carbon, multiwall carbon nanotubes, and polyvinylidene fluoride were used as both anode and cathode to assemble a symmetrical supercapacitor. The resultant supercapacitor exhibits a maximum power density of 3747 W kg-1 at an energy density of 7.71 W h kg-1 and a maximum energy density 17.1 W h kg-1 at a power density of 630 W kg-1. It displays excellent cycling stability with 91.3% of the initial specific capacitance after 3000 charging/discharging cycles. This flexible SSE in this study demonstrates a high potential for use in energy storage, conversion, and wearable device applications.

Effects of phosphor distribution and step-index remote configuration on the performance of white light-emitting diodes.

Phosphor-converted white light-emitting diodes (pc-WLEDs) are fabricated by combining CaSi2O2N2:Eu2+ and Ca2Si5N8:Eu2+ phosphors with a blue chip. Experimental results demonstrate that placing the red phosphor layer above the yellow one (Y down/R up) yields the highest luminous efficiency, making it the preferable phosphor distribution for pc-WLEDs rather than Y up/R down. This finding suggests that the extent of overlap between the emission spectrum of short-emission-wavelength phosphors and the excitation spectrum of long-emission-wavelength phosphors and their luminous efficacy of radiation should be taken into account simultaneously when studying the optical characteristics of pc-WLEDs. Compared to common pc-WLEDs with silicone gel as the remote layer, the proposed step-index remote configuration exhibits superior luminous efficiency because of reduced total internal reflection and Fresnel loss.