[en] The time reponse of a microchannel plate X-ray multiplier has been improved considerably by using a coupling construction of coaxial tapers. The experimental calibration results with laser plasma X-ray source show that the rising-time of the multiplier is less than 170 ps

[en] The emission and detection of soft x-ray from laser-produced plasma are discussed

[en] The emission and measurement of bremsstrahlung spectrum from laser plasma are discussed and the bremsstrahlung spectrometer and the measured results are described

[en] Graphene and boron nitride (GPBN) heterostructures provide a viable way to realize tunable bandgap, promising new opportunities in graphene-based nanoelectronic and optoelectronic devices. In the present study, we investigated the interplay between vacancies and graphene/h-BN interfaces in monolayer GPBN heterostructures. The energetics and kinetics of monovacancies and divacancies in monolayer GPBN heterostructures were examined using first-principle calculations. The interfaces were shown to be preferential locations for vacancy segregation. Meanwhile the kinetics of vacancies was found to be noticeably modified at interfaces, evidenced by the minimum energy paths and associated migration barriers calculations. The role of interfacial bonding configurations, energy states and polarization on the formation and diffusion of vacancies were discussed. Additionally we demonstrated that it is important to recognize the dissimilarities in the diffusion prefactor for different vacancies for accurate determination of the vacancy diffusion coefficient. Our results provide essential data for the modeling of vacancies in GPBN heterostructures, and important insights towards the precise engineering of defects, interfaces and quantum domains in the design of GPBN-based devices. (paper)

[en] Objective: To test intraoperative radiotherapy with mobile photon beam using the INTRABEAM system (Germany), and to analyze the dosimetric characteristics of low-energy photon beam using X-ray source and spherical applicators and explore its potential limitations in clinical application. Methods: A special water phantom, a parallel-plate ionization chamber, and an electrometer were used to measure the depth dose rates and isotropy of dose distribution in x/y plane of X-ray source and different spherical applicators in the INTRABEAM system. Those data were then compared with the system data. Results: For the X-ray source, the deviation of observed depth dose rate and isotropy in the x/y plane from the system data were -2.16% ± 1.36% and -1.9%∼2.1%, respectively. For applicators with different diameters, the deviation of observed depth dose rate, transfer coefficient, and isotropy in x/y plane from the system data were -10.0%∼2.3%, -8.9%∼4.2%, and -1.6%∼2.6%, respectively. Surface dose rate and dose gradient became larger with the decrease in the diameter of the spherical applicator. The measurement of depth dose rate and isotropy of X-ray source and spherical applicators showed good repeatability. The influencing factors for measurement accuracy included the positioning error of ionization chamber, energy response,noise current, and correction factor f'(R). Conclusions: This study reveals the dosimetric characteristics of the INTRABEAM system, verifies the accuracy of the system data, and obtains the data for clinical application and routine quality assurance. However, large dose gradient and small therapeutic range may limit its wide clinical application. (authors)

[en] For the X-ray laser researching toward shorter wave length, the authors set up a compact short pulse laser facility with high intensive output at the variable pulsewidth from 20 ps to 2.5 ns. Occupying a table smaller than 10 m² and with output of 2.5 J in 20 ps this facility is reported with the emphasis on the use of X-ray lasers research and laser-plasma study

[en] This work presents the design, fabrication and characterization of a modular magnetic bead-based cell separation device developed for the sequential sorting of a heterogeneous prostate cancer (CaP) cell population. The chief aim is cell sorting carried out on the basis of surface marker expression, serially selecting cellular subpopulations for capture by the use of antibody-coated magnetic beads. The markers of interest, prostate specific membrane antigen (PSMA) and CD10 were selected for their relevance to ongoing CaP development research. The separation device was fabricated out of plastic, by the use of cyclic olefin copolymer (COC) injection molding, nickel–iron electroplating and thermoplastic fusion bonding. Effective depletion and enrichment of cell subsets based on multiple surface markers was achieved. Various flow rates and incubation times were tested for optimizing the sorting procedure

[en] The effects of hydrogen charging on the mechanical response of FCC Ni and Pd under nanoindentation are systematically investigated by molecular dynamics simulations. Simulations consider a random H distribution and time scales prevent any diffusion of H during the simulations. Hydrogen charging is then found to reduce the threshold load for dislocation nucleation, i.e., the pop-in load, but only to a limited extent. After pop-in, the indentation response is largely independent of the presence of H. Furthermore, the influence of hydrogen charging on the pop-in load originates only from the hydrogen-induced swelling of the lattice. That is, H does not directly influence dislocation nucleation, either in terms of facilitating initial slip or interacting with the nascent dislocation(s). These findings suggest that rate-dependent processes, either associated with fluctuating nucleation or H transport, are necessary to interpret experimental observations of hydrogen-influenced reductions in the pop-in load.

[en] Generalized-stacking-fault energy (GSFE) serves as an important metric that prescribes dislocation behaviors in materials. In this paper, utilizing first-principle calculations and chemical bonding analysis, we studied the behaviors of generalized stacking fault in graphene and h-BN. It has been shown that the π bond formation plays a critical role in the existence of metastable stacking fault (MSF) in graphene and h-BN lattice along certain slip directions. Chemical functionalization was then proposed as an effective means to engineer the π bond, and subsequently MSF along dislocation slips within graphene and h-BN. Taking hydrogenation as a representative functionalization method, we demonstrated that, with the preferential adsorption of hydrogen along the slip line, π electrons along the slip would be saturated by adsorbed hydrogen atoms, leading to the moderation or elimination of MSF. Our study elucidates the atomic mechanism of MSF formation in graphene-like materials, and more generally, provides important insights towards predictive tuning of mechanic properties in two-dimensional nanomaterials. (letter)

[en] First-principles calculations were performed to investigate the phase stability and transition within four monolayer transition-metal dichalcogenide (TMD) systems, i.e., MX_2 (M = Mo or W and X = S or Se) under coupled electron doping and lattice deformation. With the lattice distortion and electron doping density treated as state variables, the energy surfaces of different phases were computed, and the diagrams of energetically preferred phases were constructed. These diagrams assess the competition between different phases and predict conditions of phase transitions for the TMDs considered. The interplay between lattice deformation and electron doping was identified as originating from the deformation induced band shifting and band bending. Based on our findings, a potential design strategy combining an efficient electrolytic gating and a lattice straining to achieve controllable phase engineering in TMD monolayers was demonstrated