MOLECULAR POLARIZATION INDUCTION IN CONCERTED MECHANISM OF ALKOXY MIGRATION

The rearrangement of α-substituted phenyl-α, α′-dimethoxypropanones (R1) was recently proved to he an [1, 3] siqmatropic migration of methoxy group by study of LFER, solvent effect, crossover experiment, and by other means. The rearrangement catalysed by trace of totuenesulfonic acid gave a negligible value of the Hammett reaction constant. Further experimental results show that the electronic effect of substituent on the aromatic ring for the rearrangement in neutral medium is much greater (Table 1). We propose sigmatropic migration

Intrinsic product polarization and branch ratio in the S（~1D,~3P）＋HD reaction on three electronic states

The intrinsic product polarization and intramolecular isotope effect of the S（~1D,~3P） ＋ HD reaction have been investigated on both the lowest singlet state（1A） and the triplet state（3A and 3A） potential energy surfaces by using quasi-classical trajectory and quantum mechanical methods.The calculations indicate that intramolecular isotope effects are different on the three electronic states.The stereodynamics study shows that the P（θr） distributions,P（φ r） distributions,and polarization-dependent differential cross sections（PDDCSs）（00） are sensitive to mass factor and the product angular momentum vectors are not only aligned but also oriented.

A low-latency pipeline for GRB light curve and spectrum using Fermi/GBM near real-time data

Rapid response and short time latency are very important for Time Domain Astronomy, such as the observations of Gamma-ray Bursts（GRBs） and electromagnetic（EM） counterparts of gravitational waves（GWs）. Based on near real-time Fermi/GBM data, we developed a low-latency pipeline to automatically calculate the temporal and spectral properties of GRBs. With this pipeline, some important parameters can be obtained, such as T_（90） and fluence, within ～ 20 min after the GRB trigger.For ～ 90% of GRBs, T90 and fluence are consistent with the GBM catalog results within 2σ errors.This pipeline has been used by the Gamma-ray Bursts Polarimeter（POLAR） and the Insight Hard Xray Modulation Telescope（Insight-HXMT） to follow up the bursts of interest. For GRB 170817 A, the first EM counterpart of GW events detected by Fermi/GBM and INTEGRAL/SPI-ACS, the pipeline gave T90 and spectral information 21 min after the GBM trigger, providing important information for POLAR and Insight-HXMT observations.

A Further Study of Relative Longitude Shift of Pulsar Beams

It is of great importance to study pulsar beam shape if we are concerned with emission theories and pulsar birth rate. Both observations and the ICS model show that different emission components are emitted from different heights. The relative longitude phase shifts due to different heights of the emission components and the toroidal velocity of the electrons are considered in this paper. Several possible observational effects arising from the phase shift are presented. The emission beams may not have circular cross section although the emission region may be symmetric with respect to the magnetic axis.

Stress-induced tailoring of energy storage properties in lead-free Ba_(0.85)Ca_(0.15)Zr_(0.1)Ti_(0.9)O_(3)ferroelectric bulk ceramics

In this study,the stress-modulated energy storage properties of lead-free polycrystalline Ba_(0.85)Ca_(0.15)Zr_(0.1)Ti_(0.9)O_(3)was investigated as a function of temperature from 25℃to 55℃.The externally applied uniaxial compressive stress of-160 MPa increased the recoverable energy storage density by 226%to a maximum value of 274 mJ/cm^(3),in addition to enhancing the energy storage efficiency by approximately 10%to a value of 88.2%.The macroscopic mechanical constitutive behavior is presented as well as the stress-dependent dielectric and ferroelectric properties and the Rayleigh behavior in order to elucidate the effect of stress on the energy storage properties.Importantly,the stress-induced tailoring of energy storage performance can be utilized for other nonlinear dielectric ceramics to tune their extrinsic polarization mechanisms to significantly enhance the recoverable energy density and reduce the hysteretic losses.