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Conventional electrothermal floors suffer from low heating efficiency, uneven temperature distribution across the floor surface, local overheating, and severe heat accumulation. In order to improve the heating performance, an electrothermal composite floor with graphene as the heating layer was fabricated. The relationship between time and temperature rise, the relationship between power density and temperature rise, running stability, and surface temperature distribution were investigated and analyzed after heating, and the surface temperature profiles were simulated in two and three dimensions. The results were compared with the carbon fiber electrothermal composite floor and the resistance wire electrothermal composite floor. The results indicated that the temperature of the graphene electrothermal composite floor rose to 27.1 °C, the electrothermal conversion efficiency reached 90.1% after 40 min of electrification, and the temperature distribution unevenness was 4.4 °C, which were better than the carbon fiber electrothermal composite floor and the resistance wire electrothermal composite floor. The graphene electrothermal composite floor exhibited high heating performance, thus aiding the development and manufacture of such composite flooring. [ABSTRACT FROM AUTHOR]

In this paper, a class of two-step continuity Runge-Kutta(TSCRK) methods for solving singular delay differential equations(DDEs) is presented. Analysis of numerical stability of this methods is given. We consider the two distinct cases: (i)τ ≥ h, (ii)τ < h, where the delay τ and step size h of the two-step continuity Runge-Kutta methods are both constant. The absolute stability regions of some methods are plotted and numerical examples show the efficiency of the method. [ABSTRACT FROM AUTHOR]

A rhodamine-based probe for Fe3+ was prepared and confirmed by X-ray crystallography. The probe exhibited highly selective and sensitive recognition toward Fe3+ with distinct color change. Interestingly, the probe-Fe3+ complex could detect CN- according to the strong co-ordination ability of cyanide to Fe3+. The whole recognition mechanism was explored through Job's plot, MS data and theoretical calculations. Importantly, the probe was further used for detecting Fe3+ in living cells and mouse, which exhibited excellent fluorescence imaging. [ABSTRACT FROM AUTHOR]

Rhein, a naturally occurring active anthraquinone found abundantly in various medicinal and nutritional herbs, possesses a wide spectrum of pharmacological effects. Furthermore, previous studies have reported that rhein could induce hepatotoxicity in rats. However, its cytotoxicity and potential molecular mechanisms remain unclear. Therefore, the present study aimed to investigate the cytotoxicity of rhein on HepaRG cells and the underlying mechanisms of its cytotoxicity. Our results demonstrate, by 3-(4,5-dimethyl thiazol-2-yl-)-2,5-diphenyl tetrazolium bromide (MTT) and Annexin V-fluoresce isothiocyanate (FITC)/propidium iodide (PI) double-staining assays, that rhein significantly inhibited cell viability and induced apoptosis in HepaRG cells. Moreover, rhein treatment resulted in the generation of reactive oxygen species (ROS), loss of mitochondrial membrane potential (MMP), and S phase cell cycle arrest. The results ofWestern blotting showed that rhein treatment resulted in a significant increase in the protein levels of Fas, p53, p21, Bax, cleaved caspases-3, -8, -9, and poly(ADP-ribose)polymerase (PARP). The protein expression of Bcl-2, cyclin A, and cyclin-dependent kinase 2 (CDK 2) was decreased. In conclusion, these results suggest that rhein treatment could inhibit cell viability of HepaRG cells and induce cell death through cell cycle arrest in the S phase and activation of Fas- and mitochondrial-mediated pathways of apoptosis. These findings emphasize the need to assess the risk of exposure for humans to rhein. [ABSTRACT FROM AUTHOR]

Quercus tiaoloshanica Chun et Ko, which has a narrow range of distribution, is one of the important endemic species of the tropical montane rain forest on Hainan Island, southern China. Long-term logging and habitat destruction have resulted in population decline and distribution retreat of Q. tiaoloshanica. To determine the impact of logging on the genetic diversity of Q. tiaoloshanica, the authors investigated the genetic structures using amplified fragment length polymorphism markers in four regenerated stands after logging and in one unlogged stand. Compared with the unlogged stand, the effective number of alleles per locus dropped by 1.0% in selective logging stands and by 2.0% in clear logging stands, corresponding to reductions of 3.8% and 5.2%, respectively, in mean Nei's gene diversity and 2.9% and 3.5%, respectively, in mean Shannon diversity index. No substantial genetic erosion was detected in any of the regenerated stands owing to the high tree density and high heterogeneity of the Q. tiaoloshanica stands investigated. Meanwhile, there was no natural regeneration of the species observed in a Dacrydium pierrei Hickel plantation 700 m away from the regenerated stands, suggesting the limited ability of seed dispersal of Q. tiaoloshanica. Clear logging should be undertaken cautiously because the total number of plant species dropped by 15.2% in the clear-logged stands compared with the unlogged stand. To conserve the genetic diversity of this species, as well as the plant biodiversity of tropical forests, the habitats of Q. tiaoloshanica should be protected against exploitation in terms of agricultural or other forms of land use, and some mature trees should be preserved as seed sources to maintain an adequate regeneration base for this species in the management of logging. (Managing editor: Ya-Qin HAN) [ABSTRACT FROM AUTHOR]

Multilayer dielectric mirrors (niobium pentoxide/silica) were irradiated by single 800 nm-38fs laser pulses. A circular blister feature appeared in the chirped mirrors at a wide range of laser fluence, while only existed above a few percent of the damage threshold for the high-reflector. Absorptive source of laser energy can be determined by combining theoretical simulation with focused ion beam technology. Mechanical analysis with a linear-elastic buckling model reveals the blister evolution belonging to a stable-buckling process until the blister radius confined by limited laser spot size. [ABSTRACT FROM AUTHOR]

The compression of high-energy, linearly polarized pulses in a gas-filled hollow core fiber (HCF) by using a concentric phase mask is studied theoretically. Simulation results indicate that using a properly designed concentric phase mask, a 40-fs input pulse centered at 800 nm with energy up to 10.0 mJ can be compressed to a full width at half maximum (FWHM) of less than 5 fs after propagating through a neon-filled HCF with a length of 1 m and diameter of with a transmission efficiency of 67%, which is significantly higher than that without a concentric phase mask. Pulses with energy up to 20.0 mJ can also be efficiently compressed to less than 10 fs with the concentric phase mask. The higher efficiency due to the concentric phase mask can be attributed to the redistribution of the transverse intensity profile, which reduces the effect of ionization. The proposed method exhibits great potential for generating few-cycle laser pulse sources with high energy by the HCF compressor. [ABSTRACT FROM AUTHOR]

We perform a numerical study for temporally compressing radially-polarized (RP) infrared pulses in a gas-filled hollow-core fiber (HCF). The dynamic transmission and nonlinear compression of RP pulses centered at wavelengths of 0.8 μm, 1.8 μm, 3.1 μm, and 5.0 μm in HCFs are simulated. By comparing the propagation of pulses with the same optical cycles and intensity, we find that under proper conditions these pulses can be compressed down to 2–3 cycles. In the transverse direction, the spatiotemporal beam profile ameliorates from 0.8-μm to 1.8-μm and 3.1-μm pulses before the appearance of high-order dispersion. These results show an alternative method of scaling generation for delivering RP infrared pulses in gas-filled HCFs, which can obtain energetic few-cycle pulses, and will be beneficial for relevant researches in the infrared scope. [ABSTRACT FROM AUTHOR]

We numerically study the self-compression of the optical pulses centered at 1.8- in a hollow-core fiber (HCF) filled with argon. It is found that the pulse can be self-compressed to 2 optical cycles when the input pulse energy is 0.2-mJ and the gas pressure is 500-mbar (1 bar=105 Pa). Inducing a proper positive chirp into the input pulse can lead to a shorter temporal duration after self-compression. These results will benefit the generation of energetic few-cycle mid-infrared pulses. [ABSTRACT FROM AUTHOR]

We theoretically study the field-free molecular orientation induced by a three-color laser field. The three-color laser field with a large asymmetric degree can effectively enhance the molecular orientation. In particular, when the intensity ratio of the three-color laser field is tuned to a proper value of , the molecular orientation can be improved by % compared with that of the two-color laser field at intensity ratio for the same total laser intensity of 2×10 W/cm2. Moreover, we investigate the effect of the carrier-envelope phase (CEP) on the molecular orientation and use the asymmetric degree of the laser field to explain the result. We also show the influences of the laser intensity, rotational temperature, and pulse duration on the molecular orientation. These results are meaningful for the theoretical and experimental studies on the molecular orientation. [ABSTRACT FROM AUTHOR]

We numerically study the propagation dynamics of intense optical pulses in gas-filled hollow-core fibers (HCFs). The spatiotemporal dynamics of the pulses show a transition from tightly confined to loosely confined characteristics as the fiber core is increased, which manifests as a deterioration in the spatiotemporal uniformity of the beam. It is found that using the gas pressure gradient does not enhance the beam quality in large-core HCFs, while inducing a positive chirp in the pulse to lower the peak power can improve the beam quality. This indicates that the self-focusing effect in the HCFs is the main driving force for the propagation dynamics. It also suggests that pulses at longer wavelengths are more suitable for HCFs with large cores because of the lower critical power of self-focusing, which is justified by the numerical simulations. These results will benefit the generation of energetic few-cycle pulses in large-core HCFs. [ABSTRACT FROM AUTHOR]

We theoretically study the nonlinear compression of a 20-mJ, 1030-nm picosecond chirped pulse from the thin-disk amplifier in a krypton gas-filled hollow-core fiber. The chirp from the thin-disk amplifier system has little influence on the initial pulse, however, it shows an effect on the nonlinear compression in hollow-core fiber. We use a large diameter hollow waveguide to restrict undesirable nonlinear effects such as ionization; on the other hand, we employ suitable gas pressure and fiber length to promise enough spectral broadening; with 600-μm, 6-bar (1 bar = 105 Pa), 1.8-m hollow fiber, we obtain 31.5-fs pulse. Moreover, we calculate and discuss the optimal fiber lengths and gas pressures with different initial durations induced by different grating compression angles for reaching a given bandwidth. These results are meaningful for a compression scheme from picoseconds to femtoseconds. [ABSTRACT FROM AUTHOR]

We numerically study the pulse compression approaches based on atomic or molecular gases in a hollow-core fiber. From the perspective of self-phase modulation (SPM), we give the extensive study of the SPM influence on a probe pulse with molecular phase modulation (MPM) effect. By comparing the two compression methods, we summarize their advantages and drawbacks to obtain the few-cycle pulses with micro- or millijoule energies. It is also shown that the double pump-probe approach can be used as a tunable dual-color source by adjusting the time delay between pump and probe pulses to proper values. [ABSTRACT FROM AUTHOR]

We present the experimental and numerical results of two-dimensional x-ray imaging due to fast electron transport in a solid target. A 40-μm-thick copper film target is irradiated by a 100 mJ, 50 fs normal incident laser pulse. The full width at half maximum of the x-ray photon dose is 25 μm, and the divergence angle of fast electrons is 25°–30°, which is detected by the pin-hole x-ray imaging technique. The target surface plasma layer is compressed by a ponderomotive force into a depth of 0.2λ. The plasma wave accompanied by fast electrons transporting into the target is studied by dividing the plasma into layers in a radial direction. A narrow fast electron channel, which is approximately 8 μm–10 μm in width, mainly contributes to the x-ray dose. [ABSTRACT FROM AUTHOR]