[en] CaSnO_3:Yb"3"+, Er"3"+, Li"+ upconverting phosphors are synthesized by a simple solid state method. The doping concentration of Li"+ ions is optimized by comparatively studying upconversion luminescence of samples with various Li"+ content. The effects of Yb"3"+ concentration, pumping power and temperature on chromaticity of upconversion luminescence in CaSnO_3:Yb"3"+, Er"3"+, Li"+ phosphors are investigated, the related mechanisms are discussed and the abilities to modulate chromaticity are evaluated.

[en] Background: The accuracy of dosimeter measurement of X and γ rays needs to be resolved. Purpose: The aim is to study the correction term of the equivalent process of low energy X-ray and the natural radioactive source. Methods: Instead of the standard sources, X-ray machine was adopted on the dose instrument calibration. The influence factors of the equivalence between low-energy X-ray and high-energy X or γ rays were simulated using Monte Carlo (MCNP) software. Results: The influences of distance, space scattering, response of detector on dose equivalence were obtained. The simulation results were also analyzed. Conclusion: The method can be used in dose equivalent correction for low-energy X-ray, high-energy X or γ rays, which is significant for the widespread use of X rays. (authors)

[en] In order to filter Statistical fluctuation when the α spectrum is analyzed, α spectrum smoothing method based on EMD polynomial is proposed in this paper. The code of spectrum data processing is realized on Matlab according to the smooth method. And the results showed that spectrum data after smoothing has a better effect, which is helpful to analyze α spectrum accurately. (authors)

[en] NaYF₄:Yb³⁺/Ho³⁺/Ce³⁺ upconversion phosphors were synthesized by using a citric acid assisted hydrothermal method. Both increasing the concentration of Ce³⁺ and decreasing the Yb³⁺ content are beneficial to the formation of cubic NaYF₄. When the concentration of Yb³⁺/Ho³⁺/Ce³⁺ were 20/1/20 and 5/1/10, respectively, a pure cubic phase was obtained. The spectral conversion from green to red was achieved by first increasing Ce³⁺ concentration to 10% and then decreasing the Yb³⁺ concentration to 5%. In the first half, the two cross relaxation processes between Ho³⁺ and Ce³⁺ were responsible for the modulation of the luminescence, while in the latter half, the enhanced intensity ratio of red to green emission was related to the decreased energy transfer from Ho³⁺ to Yb³⁺. Except for the sample doped with 5% Yb³⁺, 1% Ho³⁺ and 10% Ce³⁺, the total emission intensity of other samples decreased linearly with increasing sample temperature. The maximum responsibility was obtained in the case of 20% Yb³⁺, 1% Ho³⁺ and 5% Ce³⁺ doping. Compared to the Er³⁺ based luminescent temperature sensing, this novel temperature sensing not only shown little impact from pump power, but also had the identical sensitivity at various temperatures, and thus being a promising candidate for temperature sensing.

[en] Background: This research is to take energy spectrum of α particle into consideration in the measurement of radon. Purpose: We aim to find the influence factors of screening particle energy. during the process of detector design. Methods: Based on the electrostatic collection radon measurement method, in order to study the influence factors of the measurement such as aluminum foil and air layer, the reasonable radiation source and geometric model are abstracted and calculated with Geant4 software. Results: The best ranges of aluminum foil thickness and air layer thickness are obtained by analyzing their relationship with a energy, the Full Width at Half Maximum (FWHM), the energy resolution, the distance of peaks and the peaks screening power. Conclusion: With the results adopted above, the energy spectrum device is fabricated. Based on the α energy spectrum sampled in a radon chamber, the validity of this design has been proved. It provides a set of reliable data for the design of radon measuring device with electrostatic collection method. (authors)

[en] This paper used the different energies of compton scattering photon for dose instrument calibration, analysed its feasibility, and simulated the material of the target matter, its structure and size, the distance of detection and other conditions about compton scattering using Monte Carlo method, the result were compared with the theoretical value, the optimal condition of Compton scattering for dose instrument was obtained, this method has an important meaning for dose calibration on mini-type laboratory. (authors)

[en] With the problems between sampling-rate and sampling-precision in DAQ (data acquisition) card, a dual-channel data acquisition system and a date-intervening system are designed, which is based on the development platform-LabVIEW, researching on synchronization of simultaneously dual-channel data acquisition system based on virtual instrument and discovering the best acquisition project. (authors)

[en] The cubic phase KY₃F₁₀:15%Yb³⁺,1%Ho³⁺ up-converting nanocrystals are prepared by a simple hydrothermal method. Under 980 nm excitation, strong green and red emissions are produced at the same time. According to a set of steady state rate equations and the power dependence of up-conversion luminescence, it is confirmed that two-step energy transfer from Yb³⁺ to Ho³⁺dominates the population of green emission level, while the multi-phonon decay of ⁵S₂/⁵F₄ to ⁵F₅ and promotion from ⁵I₇ to ⁵F₅ are responsible for the red emission. Long-term laser irradiation leads to significant thermal effects. Based on the ratiometric luminescence temperature sensing behavior, the light to heat conversion ability is evaluated. This multi-functional nanocrystal is potentially applicable as the nano-heater for photo-thermal therapy of tumors. (paper)

[en] This paper presents a preliminary result about ultra-deep etched microstructures on 〈1 0 0〉 silicon wafer based on metal assisted chemical etching (MaCE). Honeycomb hole arrays with 50 µ m width were successfully etched, as deep as 280 µ m. The porous defects on the patterned surface and the lateral etching on the sidewall were effectively suppressed by optimizing the etchant solution. The results in this paper indicate that 〈1 0 0〉 silicon can be etched vertically with smooth sidewalls by an etchant solution containing ethanol, instead of the conventional aqueous-based solution. This improved method of MaCE has potential application in large-scale Si etching as a supplementary method to the expensive and complicated dry etching method. (paper)

[en] Highlights: • Carbon aerogel (CA) showed excellent catalytic performance for PMS activation. • Singlet oxygen (¹O₂) was the main reactive species in CA/PMS system. • The ¹O₂ can be generated via the recombination of superoxide radicals. • CA remained a high level of BPA degradation efficiency in realistic water bodies. The carbon catalyst has been widely used as a peroxymonosulfate (PMS) activator to degrade organic contaminants. The biomass carbon aerogel (CA) derived from poplar powder was synthesized in this study. CA with three-dimensional structure exhibited an excellent degradation performance of PMS activation for different types of organic contaminants including bisphenol A (BPA), rhodamine 6 G, phenol, and p-chlorophenol with the removal efficiencies up to 91%, 100%, 100%, and 60% within 60 min, respectively. It was found that singlet oxygen (¹O₂) dominated the non-radical pathway worked for BPA removal in CA/PMS system. The possible mechanism for PMS activation was discussed. A portion of ¹O₂ was produced through the transformation of superoxide radical (O₂^{• -}) in CA/PMS system. Electronic impedance spectroscopy (EIS) proved that the hierarchical structure of CA contributed to the electron transfer process for PMS activation. The ketonic/carbonyl groups (CO) on the surface of CA could serve as a possible active site to facilitate the generation of ¹O₂. In addition, CA showed superior degradation performance in actual water bodies and reusability with high-temperature regeneration treatment. This study developed an efficient and environmentally benign catalyst for water remediation of organic pollutants.