The 2H-to-1T′ phase transition in transition metal dichalcogenides (TMDs) has been exploited to phase-engineer TMDs for applications in which the metallicity of the 1T′ phase is beneficial. However, ...phase-engineered 1T′-TMDs are metastable; thus, stabilization of the 1T′ phase remains an important challenge to overcome before its properties can be exploited. Herein, we performed a systematic study of the 2H-to-1T′ phase evolution by lithiation in ultrahigh vacuum. We discovered that by hydrogenating the intercalated Li to form lithium hydride (LiH), unprecedented long-term (>3 months) air stability of the 1T′ phase can be achieved. Most importantly, this passivation method has wide applicability for other alkali metals and TMDs. Density functional theory calculations reveal that LiH is a good electron donor and stabilizes the 1T′ phase against 2H conversion, aided by the formation of a greatly enhanced interlayer dipole–dipole interaction. Nonlinear optical studies reveal that air-stable 1T′-TMDs exhibit much stronger optical Kerr nonlinearity and higher optical transparency than the 2H phase, which is promising for nonlinear photonic applications.
The cross section of the process e+e−→K+K− is measured at a number of center-of-mass energies s from 2.00 to 3.08 GeV with the BESIII detector at the Beijing Electron Positron Collider (BEPCII). The ...results provide the best precision achieved so far. A resonant structure around 2.2 GeV is observed in the cross section line shape. A Breit-Wigner fit yields a mass of M=2239.2±7.1±11.3 MeV/c2 and a width of Γ=139.8±12.3±20.6 MeV, where the first uncertainties are statistical and the second ones are systematic. In addition, the timelike electromagnetic form factor of the kaon is determined at the individual center-of-mass energy points.
The cross section of the e+e−→Λc+Λ¯c− process is measured with unprecedented precision using data collected with the BESIII detector at /¯s=4574.5, 4580.0, 4590.0 and 4599.5 MeV. The nonzero cross ...section near the Λc+Λ¯c− production threshold is cleared. At center-of-mass energies /¯s=4574.5 and 4599.5 MeV, the higher statistics data enable us to measure the Λc polar angle distributions. From these, the Λc electric over magnetic form-factor ratios (|GE/GM|) are measured for the first time. They are found to be 1.14±0.14±0.07 and 1.23±0.05±0.03, respectively, where the first uncertainties are statistical and the second are systematic.
Highly oriented polycrystalline ZnO films were deposited on Si substrate by rf reactive sputtering technique. X-ray diffraction (XRD), atomic force microscope (AFM) and the refractive index were ...employed to analyze the influence of the post-annealing treatment on the structural properties of ZnO thin films. It has been found that the grain size of ZnO thin films increases with increasing the annealing temperature, the shift of the diffraction peak position from its normal powder value was observed. AFM analysis shows that the surface roughness of ZnO films is very low at temperature between 250 and 600°C. The packing density investigation shows ZnO films can obtain high packing densities (above 0.973) in the annealing temperature rang from 450 to 600°C.
The back-streaming neutrons (back-n) is a white neutron experimental facility at the China spallation neutron source (CSNS). The time structure of the primary proton beam makes it fully applicable to ...use the time-of-flight (TOF) method for neutron energy measuring. We implemented the electronics of TOF measurement on the general-purpose readout electronics designed for all the seven detectors in back-n. The electronics are based on the peripheral component interconnect express eXtensions for instrumentation (PXIe) platform, which is composed of field digitizer modules (FDM), trigger and clock modules (TCM), and signal conditioning modules. The T0 signal synchronous to the CSNS accelerator represents the neutron emission from the target. It is the start of the time stamp. The TCM receives, synchronizes, and distributes the T0 signal to each FDM based on the PXIe backplane bus. Meanwhile, the detector signals, after being conditioned, are fed into FDMs for waveform digitizing. The first sample point of the signal waveform is the stop of the time stamp. According to the time stamp and the time of the signal over the threshold, the total TOF can be obtained. The time-to-digital converter (TDC) based on field-programmable gate array (FPGA) is implemented on the TCM to accurately acquire the time interval between the asynchronous T0 signal and the global synchronous clock phase. There is also an FPGA-based TDC on the FDM to accurately acquire the time interval between the T0 signal arriving at the FDM and the first sample point of the signal waveform. The over-threshold time of signal is obtained offline. This method for TOF measurement is efficient and not needed for additional modules. Test results showed that the accuracy of TOF is subnanosecond and can meet the requirement for back-n at the CSNS.
Genera of phytopathogenic fungi: GOPHY 3 Marin-Felix, Y.; Hernández-Restrepo, M.; Iturrieta-González, I. ...
Studies in mycology,
09/2019, Letnik:
94, Številka:
1
Journal Article
Recenzirano
Odprti dostop
This paper represents the third contribution in the Genera of Phytopathogenic Fungi (GOPHY) series. The series provides morphological descriptions, information about the pathology, distribution, ...hosts and disease symptoms for the treated genera, as well as primary and secondary DNA barcodes for the currently accepted species included in these. This third paper in the GOPHY series treats 21 genera of phytopathogenic fungi and their relatives including: Allophoma, Alternaria, Brunneosphaerella, Elsinoe, Exserohilum, Neosetophoma, Neostagonospora, Nothophoma, Parastagonospora, Phaeosphaeriopsis, Pleiocarpon, Pyrenophora, Ramichloridium, Seifertia, Seiridium, Septoriella, Setophoma, Stagonosporopsis, Stemphylium, Tubakia and Zasmidium. This study includes three new genera, 42 new species, 23 new combinations, four new names, and three typifications of older names.
Different methods are developed for simulation of microstructural evolution in metals and alloys subject to Laser Additive Manufacturing. The Monte Carlo (MC) method is combined with a new proposed ...two scales strategy for simulation of the solidification and the subsequent solid-state phase transformation in Ti–6Al–4V.The Cellular Automaton (CA) method shows its higher efficiency in comparison with MC method. Moore neighbor type with energy barrier is recommended for the CA simulation of grain growth of Al 6061. The phase field (PF) model shows that different temperature gradients lead to different columnar grains in different layers of Ti–32wt.%Nb. The computed structures are related to experimental observations.
Friction stir additive manufacturing is studied experimentally and numerically. Different to conventional friction stir welding, re-stirring and re-heating can be found
for
friction stir additive ...manufacturing. The new generated phenomena are investigated by new integrated model, which is established based on Monte Carlo method and precipitate evolution model with combination of finite element model. Corresponding experiments are performed. Results indicate that different grain morphology and size, different hardness, and different yield strength can be found in different layers. The re-stirring and re-heating to the formed layers can lead to enhancement of mechanical properties with smaller grains and with higher hardness and yield strength. In comparison with first layer, the hardness and yield strength on second layer are increased due to the decrease of the peak temperature. After 2–3 layers, the mechanical properties of formed layers are not further affected by the new added layers.