[en] An experiment that measured the parity violating (PV) asymmetry A_d in e-²H deep inelastic scattering (DIS) at Q² ~ 1.10 and 1.90 (GeV/c)² and x_B ~ 0.3 was completed in experimental Hall A at the Thomas Jefferson National Accelerator Facility. The asymmetry can be used to extract the neutral weak coupling combination (2C_2u-C_2d), providing a factor of five to six improvement over the current world data. To achieve this precision, asymmetries of the 10^-4 level needed to be measured at event rates up to 500 kHz with high electron detection efficiency and high pion background rejection capability. A specialized scaler-based counting data acquisition system (DAQ) with hardware-based particle identification was successfully implemented. The statistical quality of the asymmetry measurement agreed with the Gaussian distribution to over five orders of magnitudes and the experimental goal of 3-4% statistical uncertainty was achieved. The design and performance of the new DAQ system is presented with the preliminary asymmetry results given in the end

[en] Highlights: • String BaMoO_4:Ln"3"+ nanobeans were prepared by a hydrothermal method. • The Decay dynamics were performed to study the photoluminescence of the BaMoO_4:Eu"3"+ nanobeans. • For BaMoO_4:Er"3"+/Eu"3"+, the "2P_3_/_2 → "4I_1_1_/_2 and "2H_1_1_/_2/"4S_3_/_2 → "4I_1_5_/_2 transitions were observed. - Abstract: String BaMoO_4:Ln"3"+ (Ln = Eu, Tb, Er, and Gd) nanobeans were prepared by a hydrothermal method. The samples were characterized by transmission electron microscope, scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscope, and Raman spectrometer. Under direct excitation in the charge transfer absorption band, concentration quenching phenomenon occurs and decay dynamics were performed to study the photoluminescence of the string BaMoO_4:Eu"3"+ nanobeans. In the emission spectra of BaMoO_4:Er"3"+/Eu"3"+ under 274 nm excitation, the "2P_3_/_2 → "4I_1_1_/_2, "2H_1_1_/_2 → "4I_1_5_/_2, and "4S_3_/_2 → "4I_1_5_/_2 transitions from Er"3"+ ions were observed for the first time. In addition, the photoluminescence properties of BaMoO_4:Tb"3"+/Eu"3"+ and BaMoO_4:Gd"3"+/Eu"3"+ were also investigated.

[en] Mercurochrome-sensitized composite TiO₂/SnO₂ and ZnO/SnO₂ photoelectrochemical cells (DSC) have been fabricated from the mixture of the SnO₂ particles and the semiconductor colloid (TiO₂, ZnO). The influence of the mixed ratio on the performances of the composite semiconductor photoelectrochemical cells was studied. Comparing the composite TiO₂/SnO₂ and ZnO/SnO₂ cells with the corresponding TiO₂ and ZnO cells, the incident photon-to-current conversion efficiency of the composite cells was improved greatly. The photovoltage spectra (SPS) indicated that the dye molecule was adsorbed mainly by the TiO₂ and ZnO particles respectively in the composite cells. The energy barriers between the different semiconductors contributed to the improvement of the short-circuit photocurrent. The possible transport mechanism of the photogenerated electrons in composite cells was percolation through the SnO₂ particles

[en] Objective: To understand the treatment effect of soil covering Mill Tailing Impoundment by the investigation of surface radon exhalation rate. Methods: The Power multi-function fast radon monitor with CR-39 solid track sheet which de- signed by USC was used to measure the radon exhalation rate at four different regions in Uranium Mill Tailing Impoundment. Results: In 54 points the range of radon exhalation rate is (0.0911∼3.3951) Bq·m^-2·S^-1, with an average of 0.4107 Bq·m^-2 ·s^-1. Radon exhalation rate of some sampling point exceeds to a certain value. Conclusion: In the absence of considerating the effect of temperature, pressure, humidity, surface temperature and other factors on the radon exhalation rate, the radon exhalation rate substantially below the limits specified in the national standard. The testing results show treatment effect of soil covering is good. To some sampling point, radon exhalation rate should be monitored from time to time to observe the change trends. (authors)

[en] Highlights: • Identification of ancient Chinese iron coins nondestructive by 3D XRF. • Double Peaks Gaussian curve reveals the existence of corrosion layer. • To help archaeologists familiarize 3D XRF and broaden their research tools. Two samples of ancient Chinese coins were analyzed with a confocal three-dimensional micro-X-ray fluoroscope. The depth distributions of elemental iron (Fe), calcium (Ca) and copper (Cu) were obtained based on this non-destructive measurement method. One coin, named “Chongning Tongbao”, was certified as genuine in accordance with the available archaeological data, whereas another coin, named “Zhenglong Yuanbao”, was identified as a reproduction.

[en] One-dimension carbon self-doping g-C₃N₄ nanotubes (CNT) with abundant communicating pores were synthesized via thermal polymerization of saturated or supersaturated urea inside the framework of a melamine sponge for the first time. A ∼16% improvement in photoelectric conversion efficiency (η) is observed for the devices fabricated with a binary hybrid composite of the obtained CNT and TiO₂ compared to pure TiO₂ device. The result of EIS analysis reveals that the interfacial resistance of the TiO₂-dye|I₃⁻/I⁻ electrolyte interface of TiO₂-CNT composite cell is much lower than that of pure TiO₂ cell. In addition, the TiO₂-CNT composite cell exhibits longer electron recombination time, shorter electron transport time, and higher charge collection efficiency than those of pure TiO₂ cell. Systematic investigations reveal that the CNT boosts the light harvesting ability of the photovoltaic devices by enhancing not only the visible light absorption but also the charge separation and transfer. .

[en] Highlights: • A white-light-emitting porous fibrous membrane was fabricated via coaxial electrospinning. • The coaxial structure can effectively separate dyes and impede the energy transfer. • The porous structure can increase the light-emitting area and efficiently realize white-light emission. • Every microscopically sized individual fiber emitted white light. In this study, a white-light-emitting porous fibrous membrane was fabricated by a coaxial electrospinning method, which used a blue fluorescent organic dye as the energy-donor and a specifically designed orange fluorescent dye as the energy-acceptor. The advantage of the coaxial structure is that the spatial separation of the two dyes can be easily accomplished, which can effectively impede the energy transfer (ET) of the two dyes and result in the emission of uniform white light by every microscopically sized individual fiber. In particular, polylactide (PLA) was used as the electrospun matrix due to its satisfactory pore-forming performance under humid conditions, and the porous structure reduced the blocking effect of the polymer matrix on the fluorescent dyes and efficiently realized white-light emission. The white-light-emitting porous fibrous membrane has a unique structure, which gives it special properties such as flexibility and durability. There is great potential for this membrane to be used for next-generation lighting or display applications because of its superior performance.

[en] NiS nanoparticles modified black TiO₂ hollow nanotubes (NBTNs) are successfully synthesized via surface hydrogenation and the facile solvothermal method. The unique structure with intensified surface and interface characteristics endow NBTNs with more catalytic sites, and increase charge carrier separation efficiency with an extended charge lifetime, overwhelmingly promoting its photocatalytic performance. The resultant NBTNs possess a relatively high surface area and pore size of ∼89 m² g⁻¹ and ∼9.8 nm, respectively. The resultant NBTNs exhibit an excellent solar-driven photocatalytic hydrogen rate (3.17 mmol h⁻¹ g⁻¹), which is almost as high as that of Pt as cocatalyst, in which the apparent quantum yield of 5.4% (420 nm) is recorded for the NBTNs sample. Moreover, the turnover number can be up to 116 000 within 48 h and the turnover frequency is 2400 for NiS. This novel strategy could provide a better understanding of cocatalyst photocatalytic mechanisms, and a scheme simultaneously regulating the morphology and structure of photocatalysts for promoting H₂ generation. (paper)

[en] Magnetic-fluorescent bifunctional materials have received global attention owing to their potential in many fields. Herein, we reported a novel magnetic-fluorescent bifunctional Janus nanofiber membrane (NFM) by adding the as-prepared magnetic CoFe₂O₄ nanoparticles into the polyacrylonitrile (PAN) side (m-PAN) and the fluorescent molecules of 1,8-naphthalene anhydride (1,8-NAD) into the polyvinylpyrrolidone (PVP) side (f-PVP) via electrospinning method. The obtained m-PAN/f-PVP Janus NFM exhibited excellent magnetic performance and high fluorescent properties due to the unique structure. Compared with the m-PAN/f-PVP composite NFM, the Janus NFM showed higher fluorescent performance because the fluorescent molecules were isolated from the magnetic nanoparticles. In addition, the Janus NFM not only maintain the good self-supporting state in water but also realize a directional movement attracted by a magnet. The unique structure of Janus nanofiber is of great importance and demonstrates great potential applications. (paper)

[en] Graphitic carbon nitride (g-C₃N₄) has become an attractive visible-light-responsive photocatalyst because of its semiconductor polymer compositions and easy-modulated band structure. However, the bulk g-C₃N₄ photocatalyst has the low separation efficiency of photogenerated carriers and unsatisfied surface catalytic performance, which leads to poor photocatalytic performance. As for this, MgTi₂O₅ with high chemical stability, wide band gap and negative conduction band was used as a suitable platform for coupling with g-C₃N₄ to enhance charge separation and promoted the photoactivity. Different from common approaches, here, we propose an innovative method to construct g-C₃N₄/MgTi₂O₅ nanocomposites featuring “0 + 1 > 1” magnification effect to improve g-C₃N₄ photocatalytic performance under visible light irradiation. Additionally, compositing metal oxides of MgTi₂O₅ with g-C₃N₄ has proven to be a proper strategy to accelerate surface catalytic reactions in g-C₃N₄, and the photoinduced carriers were modulated to maintain thermodynamic equilibrium, which convincingly promotes the photocatalytic activity. The photocatalytic performance of the nanocomposites was measured by hydrogen production and CO₂ reduction under visible light. The developed g-C₃N₄/MgTi₂O₅ nanocomposites with a 5 wt.% MgTi₂O₅ exhibits the highest H₂ and CO yield under visible light and excellent stability compare to the other MgTi₂O₅ contents in composites. According to surface photo-voltage spectra, electrochemical CO₂ reduction, photoluminescence, etc. The superior performance can be related to an enhanced electron lifetime, the promoted charge transfer and the increased electronic separation property of g-C₃N₄. Our work provides an approach to overcome the defect of pure g-C₃N₄, which accesses to composite with the second component matched well. .