[en] Highlights: • LiNi_0_._5Co_0_._2Mn_0_._3O_2 is coated with lithium titanium oxide via a facile process. • Lithium titanium oxide possesses high electronic conductivity. • Electrochemical performance of the LTO-coated NCM is significantly enhanced. - Abstract: Ni-based layered LiNi_0_._5Co_0_._2Mn_0_._3O_2 (NCM) compounds coated with lithium titanium oxide for lithium ion batteries were successfully achieved through a simple solid state synthesis process using TiO_2 powder and CH_3COOLi. Systematical measurements in structure, morphology and electrochemical properties have been applied. X-ray diffraction patterns showed the existence and conversion of lithium titanium oxide (Li_4Ti_5O_1_2 and Li_7Ti_5O_1_2 are labeled as LTO). A coating layer in the form of LTO could be observed and the thickness was approximately 10 nm with uniform distribution. Similarly, XPS was performed to confirm the existence of LTO. 1.0 wt.% LTO-coated NCM material exhibited higher capacity retentions of 91.0% than that of the bare one (64.3%) after 100 cycles at cutoff voltages of 4.5 V. Meanwhile, the LTO-coated NCM material showed significantly improved thermal stability compared with the pristine sample at an elevated 60 °C. In addition, it has proved that it is effective to enhance the electrochemical performances of electrodes by LTO modification.

[en] A kinetic Monte Carlo simulation is performed in order to study the effect of Sb as a surfactant on the growth of Ge/Si(111). In our model the exchange mechanism between Ge and Sb atoms and the re-exchange mechanism in which the exchanged Ge adatom re-exchange with the lifted Sb atom to return to the surfactant layer, are considered. Our simulation shows the re-exchange process plays an important role on the growth mode transition in Ge/Sb/Si(111) system. The influences of the substrate temperature and the deposition rate on the growth of Ge/Sb/Si(111) system is discussed. (condensed matter: structural, mechanical, and thermal properties)

[en] Highlights: • Novel CdS/CdSe composite windows for CdTe cell were prepared by pulsed laser deposition. • SEM images show that CdS/CdSe composite windows are stacking together as the design. • CdTe cells with CdS/CdSe composite windows improved the blue response. • CdTe cells with composite windows show an obvious red shift in the absorption edge. • The volume proportion of CdSe affects the performance of CdTe solar cell. - Abstract: A novel CdS/CdSe composite window structure was designed and then the corresponding films were prepared by pulsed laser deposition as an improved window layer for CdTe-based solar cells. Two types of this composite window structure with 5 cycles and 10 cycles CdS/CdSe respectively both combined with CdS layers were prepared at 200 °C compared with pure CdS window layer and finally were applied into CdTe thin film solar cells. The cross section and surface morphology of the two composite window layers were monitored by using scanning electron microscopy and the result shows that the pulsed laser deposited composite window layers with good crystallinity are stacking together as the design. The devices based on CdS/CdSe composite window layers have demonstrated the enhanced photocurrent collection from both short and long wavelength regions compared to CdS/CdTe solar cell. The efficiency of the best reference CdS/CdTe solar cell was 10.72%. And the device with 5 cycles CdS/CdSe composite window showed efficiency of 12.61% with V_O_C of 772.92 mV, J_S_C of 25.11 mA/cm"2 and FF of 64.95%. In addition, there are some differences which exist within the optical transmittance spectra and QE curves between the two CdS/CdSe composite window samples, indicating that the volume proportion of CdSe may influence the performance of CdTe thin film solar cell.

[en] Oxygen incorporation into ZnSe thin films in Ar/O₂ or O₂ ambient during radio-frequency sputtering was studied in this paper. With the increase of oxygen partial pressure ratio, the poor crystalline quality occurred in the films accompanying with a SeO₂ secondary phase. The values of optical band gap for the films increased after light oxygen doping, ranging from 2.65 to 2.88 eV, which indicates the formation of ZnSeO ternary compounds. The near-band edge emission was observed in all samples, i.e., electronic transitions from the valence band to the conduction band. Nevertheless, heavy incorporation of O in ZnSe thin films led to the formation of the thin films with wide energy band gap (∼5.61 eV) and high optical transmittance (∼90%). X-ray photoelectron spectroscopy spectra indicate that oxygen atoms ionized by plasma enhanced the formation of SeO₂ bonds with Se of ZnSe under the non-equilibrium conditions and many oxygen ions incorporated in the random sites, resulting in the formation of amorphous states. - Highlights: • Oxygen incorporation into ZnSe thin films in Ar/O₂ or O₂ ambient during radio-frequency sputtering was studied. • The formation of ZnSeO ternary compounds occurred after light oxygen doping. • The enhancement of bandgap for heavily oxygen incorporated ZnSe thin films is due to the amorphous SeO₂ formation.

[en] Objective: To perform a routine quality assurance procedure for Truebeam multi-leaf collimator (MLC) using MLC quality assurance (QA) phantom, verifying the reliability of MLC during the treatment. Methods: MLC QA phantom was a specialized phantom for multi-leaf collimator QA, and contained five radio-opaque spheres that were embedded in an L-shape. The phantom was placed isocentrically on the Truebeam treatment couch for the tests. A quality assurance plan was settled up in the Eclipse v10.0 so that the fields for acquiring the necessary images could be created. The images were acquired by the electronic portal imaging device (EPID), and imported into the PIPSpro software for the analysis. The tests were delivered once a week for six weeks to verify consistency of the delivery, and the images were acquired in the same manner each time. Results: For the leaf position test, the average position error was (0.21 ± 0.02) mm. The leaf width was measured at the isocenter, and the average error was (0.04 ± 0.02) mm for the leaf width test. Multi-Port test showed the dynamic leaf shift error, the average error was (0.26 ± 0.04) mm. For the leaf transmission test, the average inter-leaf leakage value was 1.0% ± 0.14%. Conclusions: The MLC system of Truebeam could operate very well and the QA phantom is a useful test tool for the MLC QA. (authors)

[en] Objective: To compare IMSure QA and MatriXX for intensity modulated radiotherapy plans, and to investigate the credibility of IMSure QA software. Methods: Ten patients receiving intensity modulated radiotherapy were randomly chosen for the quality assurance plans with IMSure QA and MatriXX. Results: The overall average of percentage pass points in 3% and 3 mm were (98.1±0.8)% with IMSure QA, and (97.9±0.6)% with MatriXX(t = 0.86, P > 0.05). Conclusion: IMSure QA can be a reliable verification tool for IMRT QA. (authors)

[en] Objective: To compare the dosimetric difference of stereotactic body radiation therapy (SBRT) plans for spine metastasis using 6 MV X-ray flattening filter free (FFF) and flattening filter (FF) modes. Methods: A total of nine previously treated patients with a total of twelve spine metastasis were retrospectively included and replanned using FFF-SBRT and FF-SBRT, respectively. The dose-volume histograms (DVH), target conformity index (CI), monitor unites (MUs) and treatment time of target volume, organs at risk and normal tissues were compared between the plans. Results Both FFF-SBRT and FF-SBRT met the clinical objectives. Dose distribution of target volume, organs at risk and normal tissues were similar. MUs of the FFF-SBRT were significantly higher than that of FF-SBRT (t = -5.20, P < 0.01), while the treatment time was almost half of the latter (t = 17.27, P < 0.01). Conclusions: Two plan modes are both clinically acceptable. FFF-SBRT plans are delivered in less time and with better efficiency. Trial registration Chinese clinical trial registry, ChiCTR-TRC-14004281. (authors)

[en] Objective: To analyze the health status of officers and soldiers exposed to radioactive materials. Methods: 73 convalescents who had been exposed to radioactive substances in our hospital in 2019 were selected as the observation group, and 80 convalescents who had not been exposed to radioactive substances in the same period were selected as the control group. The main observation items include subjective symptoms, blood routine (white blood cell count, red blood cells, platelets, hemoglobin), thyroid function (T3, T4, TSH), Eye Lens Examination and chromosome aberration analysis. Results: Compared with the control group, there was significant difference in subjective symptoms, but no significant difference in blood routine, thyroid function, Eye Lens and chromosome aberration. Conclusion: The peripheral blood picture, thyroid function, Eye Lens and cytogenetics of officers and soldiers exposed to radioactive materials were not affected by their work, but it is necessary to carry out mental health education, psychological service and radiation protection education. (authors)

[en] Graphical abstract: - Highlights: • The large-area CdTe film has been prepared by PVD under the pressure of 0.9 kPa. • The as-prepared CdTe thin film processes excellent photovoltaic properties. • This technique is suitable for depositing large-area CdTe thin film. • The 14.6% champion efficiency CdS/CdTe cell has been achieved. - Abstract: The Cadmium telluride (CdTe) thin film has been prepared by physical vapor deposition (PVD), the Ar + O_2 pressure is about 0.9 kPa. This method is a newer technique to deposit CdTe thin film in large area, and the size of the film is 30 × 40 cm"2. This method is much different from the close-spaced sublimation (CSS), as the relevance between the source temperature and the substrate temperature is weak, and the gas phase of CdTe is transferred to the substrate by Ar + O_2 flow. Through this method, the compact and uniform CdTe film (30 × 40 cm"2) has been achieved, and the performances of the CdTe thin film have been determined by transmission spectrum, SEM and XRD. The film is observed to be compact with a good crystallinity, the CdTe is polycrystalline with a cubic structure and a strongly preferred (1 1 1) orientation. Using the CdTe thin film (3 × 5 cm"2) which is taken from the deposited large-area film, the 14.6% efficiency CdS/CdTe thin film solar cell has been prepared successfully. The structure of the cell is glass/FTO/CdS/CdTe/graphite slurry/Au, short circuit current density (J_s_c) of the cell is 26.9 mA/cm"2, open circuit voltage (V_o_c) is 823 mV, and filling factor (FF) is 66.05%. This technique can be a quite promising method to apply in the industrial production, as it has great prospects in the fabricating of large-area CdTe film.

[en] The process of the multilayer growth of Pt on Pt (111) is studied by using a Monte Carlo model with realistic physical parameters. The effects of the substrate temperature, the ES barrier, and the deposition rate on the growth mode have been investigated. Gradual transitions of the surface roughness from oscillatory to non-oscillatory behavior and then back to oscillatory behavior are observed while increasing the substrate temperature from 270 K to 620 K. It is found that the growth mode depends strongly on ES barrier over the whole temperatures and the deposition rate of atoms effectively affects the growth mode. The simulation results are consistent with many experimental observations for homoexpitaxy on a Pt (111) substrate.