Vol.31,

The collection efficiency of monitor parallel plate ionization chambers is the main uncertainty in the beam control of pencil beam scanning systems. Existing calculation methods for collection efficiency in photon or passive scattering proton systems have not considered the characteristics of non-uniform charge density in pencil beam scanning systems. In this study, Boag’s theory was applied to a proton pencil beam scanning system. The transverse distribution of charge density in the ionization chamber was considered to be a Gaussian function and an analytical solution was derived to calculate collection efficiency in the beam spot area. This calculation method is called the integral method and it was used to investigate the effects of beam parameters on collection efficiency. It was determined that collection efficiency is positively correlated with applied voltage, beam size, and beam energy, but negatively correlated with beam current intensity. Additionally, it was confirmed that collection efficiency is improved when the air filling the monitor parallel plate ionization chamber is replaced with nitrogen.

433

The tensor parts of Skyrme interactions are constrained from the collective charge-exchange Spin-Dipole (SD) and Gamow-Teller (GT) excitation energies in ⁹⁰Zr and ²⁰⁸Pb, together with the isotopic dependence of energy splitting between proton h_11/2 and g_7/2 single-particle orbits along the Z=50 isotopes. With the optimized tensor interactions, the binding energies of spherical or weakly deformed nuclei with A=54 228 are studied systematically. The present results show that the global effect of tensor interaction is attractive, and systematically increases the binding energies of all these nuclei and makes the nuclei more bound. The root mean squared deviation (RMSD) of the calculated binding energies from the experimental values is significantly improved by the optimized tensor interactions and the contribution of the tensor interaction to the binding energy is estimated.

351

With the development of radioactive beam facilities, studies concerning the shell evolution of unstable nuclei has recently gained prominence. Intruder components, particularly s-wave intrusion, in the low-lying states of light neutron-rich nuclei near N = 8 are of importance in the study of shell evolution. The use of single-nucleon transfer reactions in inverse kinematics has been a sensitive tool that can be used to quantitatively investigate the single-particle orbital component of selectively populated states. The spin-parity, spectroscopic factor (or single-particle strength), and effective single-particle energy can all be extracted from such reactions. These observables are often useful to explain the nature of shell evolution, and to constrain, check, and test the parameters used in nuclear structure models. In this article, the experimental studies of the intruder components in low-lying states of neutron-rich nuclei of He, Li, Be, B, and C isotopes using various single-nucleon transfer reactions are reviewed. The focus is laid on the precise determination of the intruder s-wave strength in low-lying states.

417

Schottky diodes and PN junctions were utilized as energy converting structures in ZnO-based betavoltaic batteries, in which 0.101121 Ci ⁶³Ni was selected as the beta source. The time-related electrical properties were obtained using Monte Carlo simulations. For the n-type ZnO, the Pt/ZnO Schottky diode had the highest energy conversion efficiency, and the Ni/ZnO Schottky diode had the largest I_sc. The overall electrical performance of PN junctions is better than that of Schottky diodes. The lifetimes of Pt/ZnO and Ni/ZnO are longer than for other Schottky devices, coming close to those of PN junctions. Considering that Schottky diodes are easier to fabricate and independent of p-type semiconductors, Pt/ZnO and Ni/ZnO diodes offer alternatives to PN-junction-based betavoltaic batteries.

319

Amino acids are the building blocks of proteins, which are the most abundant macromolecules in living cells. From the standpoint of the photon interaction cross sections of amino acids, the mass attenuation coefficients, half and tenth value layers, mean free path, effective atomic and electronic cross sections, effective atomic number, and effective electron density of fifteen essential amino acids have been determined for ¹³³Ba, ¹³⁷Cs, and ⁶⁰Co gamma ray sources. The MCNP-4C code and the XCOM program have been used to calculate these parameters. The results have been compared to the available experimental and theoretical data. The theoretical results agreed with the experimental data, with RD values of ≤±7%. In the energy region of 81 to 1332.5 keV, it was found that the µ_m, σ_a, and σ_e values of the amino acids decreased as the photon energy increased, and the increasing density of amino acids had no steady effect on these quantities. Additionally, results demonstrated that the HVL, TVL and MFP values increased with the increase in photon energy. The µ_m, σ_a and Z_eff values of aspartic acid were the highest among those of all amino acids, and they were the lowest for isoleucine. The Z_eff value of each sample containing H, C, N, and O atoms was nearly constant in the studied energy region. The N_eff values of the studied amino acids varied in the range of 3.14 × 10²³ – 3.44 × 10²³ electron/g. Furthermore, the N_eff values were approximately independent of the amino acid type in this energy region.

477

Ionizing radiation is a promising method for dye degradation and textile coloration using commonly used azo dyes and small-molecular-weight organic dyes. Thus, the stability of the molecular structure of an azo dye is important for ionizing radiation. Disperse Blue 79, as an example azo dyes, was dissolved in deionized water and irradiated with gamma rays or an electron beam (EB) to investigate the radiation-induced effects on the molecular structure. Ultraviolet visible spectroscopy (UV-Vis), nuclear magnetic resonance spectra (NMR) analysis and mass spectrometry (MS) indicated that acetoxy and methoxyl were easily cleaved on irradiation of the aqueous dye solution but retained a stable structure on irradiation of powdered dye. Gamma rays and EB showed similar effects on the decomposition process. Chromaticity changes using the Lab* method showed that the dye turned to dark yellow and the value of b* of the irradiated dyes increased with the absorbed dose, which indicated that Disperse Blue 79 could be partly decomposed in an aqueous solution with an absorbed dose of 10 kGy. Furthermore, the results demonstrated that Disperse Blue 79 in powder form successfully resisted gamma-ray and EB irradiation but partly decomposed in aqueous solution.

344

Polylactic acid (PLA) has been extensively applied in the fields of biology and renewable biodegradable materials because of its superior biodegradability. PLA has excellent potential as a renewable biodegradable adsorbent in wastewater treatment. However, its poor photocatalytic properties have hindered its practical application. In this study, polyvinylpyrrolidone (PVPP) or glutaraldehyde (GA) was utilized as an adhesive agent to prepare Ag/AgCl/PLA photocatalysts with highly efficient visible light photocatalysis on a PLA fabric by utilizing the electron beam irradiation method. The photocatalytic activities of the Ag/AgCl/PLA samples were examined under visible light irradiation to analyze the degradation of methylene blue (MB) and chloramphenicol (CPL). Our experimental results demonstrate that the nanomaterial Ag/AgCl was uniformly distributed on the PLA fiber surface; this can be attributed to the effects of the crosslinking PVPP or GA. Under electron beam irradiation, adding crosslinking PVPP (or GA) is beneficial to the loading of Ag/AgCl onto the PLA. For the composite Ag/AgCl/PLA, the degradation rate for MB was as high as 97% after 150 min of visible light irradiation. The addition of 4 mg/ml of Ag/AgCl solution resulted in the greatest photocatalytic activity for CPL, and we advanced the possible degradation pathways of CPL with the best sample. Additionally, the as-prepared composite Ag/AgCl/PLA exhibited favorable antibacterial activity against E. coli and S. aureus, with a bacterial removal rate of >77%.

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