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• In this paper, a RI optical fiber sensor with T compensation based on cascaded MZI and IMI is proposed and experimentally demonstrated. • Within the RI range of 1.3333–1.3640 and T range of 0–60 °C, the sensor achieves a sensitivity of 797.41 nm/RIU and 0.12 nm/°C. • The cross-sensitive problem between RI and T is eliminated by matrix demodulation method. Optical fiber refractive index (RI) sensor with temperature (T) compensation has important application values in biomedicine and environmental monitoring. In order to solve the problem that the detection accuracy of liquid RI is affected by T in practical applications, a T -compensated RI fiber sensor based on cascaded Mach-Zehnder interference (MZI) and multimode interference (IMI) is proposed in this paper. Experimental results showed the proposed sensor achieved a sensitivity of 797.41 nm/RIU for the measurement of RI in the range of 1.3333–1.3640, and a sensitivity of 0.120 nm/°C for the measurement of T in the range of 0–60 °C. The resolution (R) of RI and T measurements reached 2.5 × 10−5 RIU and 0.167 °C, respectively. The detection limits (DL) of RI and T measurements are 3.135 × 10−8 RIU and 1.392 °C, respectively. A matrix is obtained to demodulate the cross-sensitivity in RI and T measurements. The proposed sensor shows the advantages of simple structure, low hysteresis, and good stability. [ABSTRACT FROM AUTHOR]

Pd- or Pt-based precious catalysts (PPC) are considered to be the best candidates toward high performance directly ethanol fuel cells (DEFC) applications, owing to their high intrinsic activity for ethanol oxidation reaction (EOR). However, the current major barrier for their commercialization is incompletely oxidized intermediates (IOI, such as CO) that poison the catalysts to affect the durability of the cells. Meanwhile, deactivated PPC catalyst is difficult to be recycled, thus impairing the economic benefits for the commercial applications. Moreover, because of the side effects of additive corrosion and aging, the carbon and organic binders widely used in current catalyst design would make the interactions of the IOI more complex to accelerate activity loss. Here, we report a Pd/amorphous SrRuO 3 (Pd/a-SrRuO 3) hybrid film as a promising material to overcome these problems. Perovskite SrRuO 3 can effectively generate oxygen-contains (*OH, *OOH) for intermediates oxidation, providing an ideal platform to promote self-cleaning of CO on Pd activity sites. On the other hand, in analogy to typical self-adapting effect of amorphous catalyst in oxygen reduction reaction process, metastable state of amorphous SrRuO 3 in this work is expected to prolong the activity adaptation region at the initial stage of cycling. Furthermore, our conceptual framework of directly depositing Pd/a-SrRuO 3 film on operational electrode provides an effective solution to avoid the side effects related with carbon and binders, leading to superior reactivation phenomena with 98% efficiency. As a result, our designed Pd/a-SrRuO 3 hybrid film exhibits superior EOR activity (4.0 A mg-1 Pd), durability (i-t, 60,000s), self-adapting region (exceeding 400 cycles with ending activity of 3.0 A mg-1 Pd at 1000th cycle), and also a long-term operation (CP) up to 300,000s with 10 times reactivation. This demonstration of a Pd/Pt-based hybrid catalyst with dual-capability of self-cleaning and self-adapting characteristics is an important step towards the development of highly durable EOR catalysts, with an enormous potential to promote practical application of DEFC. We have developed a facile and versatile strategy towards high stability and fast activity recovery ethanol oxidation electrocatalysis using Pd/amorphous SrRuO 3 hybrid film via paused layer deposition technology (PLD). This binder- and carbon-free film endow the Pd/amorphous SrRuO 3 anode catalyst with self-adapting, self-cleaning and reactivation properties. These properties significantly enhanced the EOR durability and first prolonged the long-term operation time to 30,0000s. Image 1 • A carbon- and binder-free Pd/a-SrRuO3 film has been designed and used as a novel ethanol oxidation catalyst. • This hybrid film possess high oxygen-contains generation activity for CO oxidation. • The amorphous SrRuO3 has been demonstrated have a self-adapting behavior for EOR. • This hybrid film possess an exciting durability of 300,000s, which surpassed the records of current Pt/Pd based catalysts. [ABSTRACT FROM AUTHOR]

• A cryogenic temperature sensor based on fiber optic Sagnac interferometer was proposed and experimentally demonstrated. • The proposed sensor had an average temperature sensitivity of 1.74 nm/K in a wide temperature range of 320–170 K. • Free spectral range (FSR) was used to calibrate the dip wavelength as the variation of temperature exceeded an FSR. Accurate measurement of cryogenic temperature is crucial for various scientific and technological applications. In this paper, we experimentally investigated a fiber optic cryogenic temperature sensor based on a Sagnac interferometer (SI) with a panda polarization-maintaining fiber (PPMF). The PPMF used as the temperature sensing probe in SI enhanced the cryogenic temperature measurement sensitivity by two orders of magnitude compared to most of the published literature. The value of free spectral range (FSR) was used to label the dip wavelength as the movement of the spectrum exceeding an FSR in a large temperature variation scale. Experimental results demonstrated that the proposed sensor achieved an average measurement sensitivity of 1.8 nm/K in a wide temperature range of 170–320 K. Owing to high sensitivity, low hysteresis, and easy fabrication, our proposed sensor emerges as an ideal solution for cryogenic temperature detection. [ABSTRACT FROM AUTHOR]

Amorphous polymer-derived Si(Al)CNO ceramics with different Al contents were successfully prepared using polyvinylsilazane (PVSZ) doped with different mass fractions (0 to 15 wt%) of aluminum tri-sec-butoxide (ASB) as the precursors. The thermogravimetric, crystal morphology, microstructure, electrical conductivity and dielectric properties of Si(Al)CNO ceramics were characterized and tested, respectively. The results show that the porosity of Si(Al)CNO ceramics first decreased and then increased with the increase of ASB doping content. The electrical conductivity of SiAlCNO-5, SiAlCNO-10 and SiAlCNO-15 ceramics gradually decreased from 2.80 × 10-9 to 0.89 × 10-9 (Ω cm)-1. Their conductivity was related to free carbon in the ceramics based on Raman spectroscopy. The average permittivity of SiCNO, SiAlCNO-5, SiAlCNO-10 and SiAlCNO-15 ceramics gradually increased from 3.63 to 3.93 with the increase of ASB doping content in X-band. The dielectric loss of SiAlCNO ceramics doped with ASB was smaller than that of SiCNO ceramics. But with the continuous increase of ASB doping content, the dielectric loss of SiAlCNO ceramics also increased. The permittivity and dielectric loss of Si(Al)CNO ceramics were related to their porosity and electrical conductivity. The average absorption coefficient of Si(Al)CNO ceramics were less than 0.020, while their transmission coefficient were greater than 0.500. It was found that the amorphous Si(Al)CNO ceramics exhibit good electromagnetic wave transmission properties. [ABSTRACT FROM AUTHOR]

Highlights • Corrective model for elemental EDXRF intensities in the slurry is built. • Slurry's concentration is assessed with the Compton-scattered X-ray intensity. • Minimum limitation of slurry velocity is given as the detecting condition. • Stability and accuracy of proposed technique are verified and discussed. • Real-time monitoring of slurry elemental grade is achieved with this technique. Abstract The accuracy of energy dispersion X-ray fluorescence spectrometry (EDXRF) decreases via the online detection of slurry grade, which is due to the matrix difference caused by varying slurry components and processes. Among these, the most significant influence is the water content in the slurry, which reduces the X-ray fluorescence intensity of target elements that the detector receives. In this paper, a novel online detection method based on a correction model of X-ray fluorescence intensity is proposed. Using the mineral particle settling model as a foundation, the minimum slurry velocity was first derived to satisfy the condition of pulp content uniformity. Then, the impact of slurry concentration on the X-ray fluorescence intensity was analyzed. An intensity correction model was built, which accounted for the impact of water in slurry on the characteristic X-ray fluorescence intensity of the target elements. The overall methodology was thoroughly validated through several experiments, and was compared with the traditional EDXRF method. The experimental results indicated that the standard deviation of the target's elemental slurry grade dropped by more than 60% for lead and 40% for zinc. Meanwhile, the average relative error of the slurry's elemental grade was reduced by more than 80% for lead and 90% for zinc. The accuracy and stability of online slurry grade detection were therefore significantly improved. [ABSTRACT FROM AUTHOR]

Polymethacrylimide (PMI) foams reinforced composite Kagome honeycomb sandwich structures (PKCSSs) are a new class of structure with great application potential in aerospace and navy. They have the advantages of convenient processing, low production cost, and high modulus and strength with light weight. In this paper, five PKCSS specimens with different sizes were fabricated and the size effect was studied through three-point bending (TPB) tests. By analyzing unit cell structures, theoretical models were established for PKCSS equivalent bending stiffness and core density. Combining bending failure theory of sandwich structures, PKCSS bending failure equation was derived. It was witnessed that experimental results were highly consistent with those obtained from the theoretical model. Relationships among equivalent modulus, core density, rib width, node spacing, and rib angle were also studied. Factors affecting the ultimate bending strength of PKCSS were analyzed and critical strength surface and corresponding failure mode maps were determined. This study revealed the effect of structural size on the bending characteristics of PKCSS, discussed the change rule of PKCSS bending strength and stiffness, and determined the optimal size design ratio and design suggestions. [ABSTRACT FROM AUTHOR]

In this study, a density functional theory method is employed to investigate the surface charge transfer doping of diamond by chromium trioxide (CrO 3) with high electron affinity. Superior surface charge transfer of the hydrogenated diamond surface is demonstrated using CrO 3 as an electron acceptor. The charge density difference and Bader charge analysis reveal that the electrons are transferred from the diamond surface to CrO 3 molecule, leading to the formation of two-dimensional hole gas, and the holes left in the diamond surface increase the conductivity of the diamond surface. The analysis of electronic structure indicates that areal hole density as large as 9.85 × 1013cm−2 for CrO 3 -doped diamond surface can be achieved. Besides, the optical absorption near infrared region of the hydrogenated diamond surface is greatly enhanced upon CrO 3 doping, which implies that this CrO 3 -doped diamond surface is a promising candidate for optoelectronic materials. The present study provides an in-depth theoretical understanding of the formation of two-dimensional hole gas on diamond surface induced by a new transition metal oxide, and predicts that the CrO 3 -doped diamond surface may have important implications in electronic and optoelectronic devices. Unlabelled Image • First theoretical study of the surface transfer doping of diamond by a novel transition metal oxide CrO 3. • Theoretically predict that a hole density of as high as 9.83 × 1013cm−2 for CrO 3 -doped diamond surface could be achieved. • The optical absorption of the hydrogenated diamond surface near infrared region is enhanced by CrO 3 doping. [ABSTRACT FROM AUTHOR]