Manifestation of external field effect in time-resolved photo-dissociation dynamics of LiF

The photo-dissociation dynamics of LiF is investigated with newly constructed accurate ab initio potential energy curves （PECs） using the time-dependent quantum wave packet method. The oscillations and decay of the wave packet on the adiabats as a function of time are given, which can be compared with the femtosecond transition-state （FTS） spectroscopy. The photo-absorption spectra and the kinetic-energy distribution of the dissociation fragments, which can exhibit the vibration-level structure and the dispersion of the wave packet, respectively, are also obtained. The investigation shows a blue shift of the band center for the photo-absorption spectrum and multiple peaks in the kinetic-energy spectrum with increasing laser intensity, which can be attributed to external field effects. By analyzing the oscillations of the wave packet evolving on the upper adiabat, an approximate inversion scheme is devised to roughly deduce its shape.

Study on Water Pollution and Control in China

In recent years, water pollution has become increasingly serious in China. Meanwhile, decrease of water bodies in quality, frequent pollution incidents, safety of drinking water and water shortage have become prominent day by day. However, water pollution can not be controlled effectively. To clear underlying reasons for increasingly worsening water environment, the external effects of pollution behavior and fictitious property right of pollution control bodies were analyzed using property right theory, and then internal reasons for serious water pollution were discussed. Fi- nally, control measures of water pollution were put forward.

Highly efficient hybrid warm white organic light-emitting diodes using a blue thermally activated delayed fluorescence emitter: exploiting the external heavy-atom effect

To attain high efficiencies in hybrid white organic light-emitting diodes(WOLEDs),mutual quenching of the fluorophors and phosphors should be minimized.Efforts have been devoted to reducing the triplet quenching of phosphors;however,the quenching of fluorophors by the external heavy-atom effect(EHA)introduced by the phosphors is often ignored.Here,we observed that conventional fluorophors and fluorophors with thermally activated delayed fluorescence(TADF)behave differently in the presence of EHA perturbers.The efficiencies of the conventional fluorophors suffer greatly from the EHA,whereas the TADF fluorophors exhibit negligible changes,which makes TADF materials ideal fluorophors for hybrid devices.WOLEDs using a blue TADF fluorophor and an orange phosphor achieve a maximum forward viewing external quantum efficiency of 19.6%and a maximum forward viewing power efficiency of 50.2 lm W^(-1),among the best values for hybrid WOLEDs.This report is the first time that the EHA effect has been considered in hybrid WOLEDs and that a general strategy toward highly efficient hybrid WOLEDs with simple structures is proposed.

Influence of external electric field on piezotronic effect in ZnO nanowires

In this work, the piezotronic effect is investigated for the first time in external electric fields ranging from 0 V·cm-I to 2,000 V·cm-1 by using n-type ZnO nanowires supported by a flexible substrate. In the presence of an external electric field, the Schottky barrier height （SBH） is lowered by the image force, allowing more free carriers to pass through the metal-semiconductor junction and enhancing the screening effect on positive piezoelectric polarization charges. As the strength of the external electric field increases, the piezotronic effect is significantly suppressed and the metal-semiconductor contact finally exhibits Ohmic behavior. The experimental results show that devices can be classified into three groups, corresponding to low, moderate, and high carrier densities of the nanowires used. This work not only helps us to explicate the basic physical mechanism of the piezotronic effect in a harsh environment in an electric field but also provides guidelines for future design and fabrication of piezotronic devices.

Study on eliminating noises in short-period data of geomagnetic intensity by using nu-merical multichannel predictive filtering

The effectiveness of eliminating the noises in short-period data of geomagnetic intensity recorded in a little seismo-geomagnetic array by using numerical multichannel predictive filtering has been studied. The result shows that this technique is effective to fit external magnetic disturbance to inner electromagnetic induced difference field and reduce the noise level of difference data successfully. The filter quality factor Q of two examples in this work are 0. 86 and 0.68 respectively. The spectral analysis shows that during geomagnetic-calm days the fourfold-frequency harmonics of S q in difference data are main components. The length of the optimum filter depends on not only the frequency of predicable energy in difference data but also maybe the phase difference between input and expected output data. It is difficult to obtain the filter fitting both the data during magnetic-disturbed days and calm days. The result shows that the conductivity in Yanqing-Huailai basin west to Beijing may be much non-uniform.

Electric-field induced fluctuations in laser generated plasma plume

The effect of an external electric field on laser-generated plasma has been studied.It is observed that the laser-generated plasma can be used for the ignition of a spark in the presence of a low voltage external electric field.An eight-fold emission intensity enhancement in Cu I spectral lines are measured as compared to the signal intensity in the absence of an external electric field.The plasma parameters remain the same initially,up to a few microseconds after the generation of plasma,and this feature makes it more interesting for the quantitative analysis of any sample using laser induced breakdown spectroscopy(LIBS).In the presence of an external electric field,fluctuations(contraction and expansion)in the laser-generated plasma are observed which increase the plasma decay time and consequently result in enhanced signal intensity.

Noise Effects in the Mode-Locked External Cavity Lasers

Effect of high level of spontaneous and carrier noise on mode-locked hybrid soliton pulse source and relative intensity noise is described. Transform limited pulses are not generated over a wide frequency range because of these noises.

The effects of enhanced external counterpulsation on the serum level of C-reactive protein and endothelin-1 in patients with ischemic stroke

Objective To explore the effects of enhanced external counterpulsation(EECP)on the serum level of C-reactive protein and endothelin-1 in patients with cerebral ischemic stroke,to provide clinical evidence for the treatment and secondary prevention of patients with serebral ischemic stroke.Methods Total 187 patients with ischemic stroke and enrolled measure the serum level

Influence of External Interface Normal Stress on the Growth of Cu-Sn IMC During Aging

A U-shape clamp was designed to apply stress perpendicular to the interface of Cu/Sn/Cu solder joints,and its influence on the growth behavior of Cu-Sn intermetallic compound(IMC)during thermal aging at 150℃ was investigated.The results show that compared with the sample at general stress-free state,the growth rate of IMC under compression is faster,while that under tension is slower.Moreover,the interface between IMC and Sn is smoother under compressive stress,and the corresponding IMC grains are smaller and more uniform than that under tensile stress.According to the growth kinetic analysis,the growth of IMC under general,compressive and tensile states is all controlled by the combination of grain boundary diffusion and volume diffusion with a similar growth exponent(n≈0.4).However,external stress can affect the Ostwald ripening process of grain growth,causing a change of grain size and grain boundary density in the IMC layer.As a result,the IMC growth behavior at the interface of the solder joint will be affected by the applied external normal stress.

Optimum rolling speed and relevant temperature-and reduction-dependent interfacial friction behavior during the break-down rolling of AZ31B alloy

The present study aimed to determine the optimum rolling speed for break-down rolling of as-cast AZ31 B alloy and investigated the friction behavior associated with temperature-and reduction-sensitivity at the roll/plate contact interface. Tensile testing, formability evaluation and microstructural studies relevant to different rolling speeds were performed and finally the optimum operating rolling speed（50.0 ± 0.8 m/min） was obtained. Further, the effects of rolling reduction and initial temperature were assessed on the temperature variation, lateral spread and interfacial friction behavior at optimum rolling speed. The results showed that lower rolling speed（18.0 ± 0.8 m/min） resulted in an incompletely recrystallized structure where twins occupied relatively high volume fraction. Twinning dominated the deformation at rolling speed exceeding the optimum, resulting in the local recrystallization with shear bands and coarse grains. Rolling at 50.0 ± 0.8 m/min could get the best overall tensile properties and rolling formability due to the relatively high recrystallization degree and microstructure uniformity. An inverse method has been developed to determine the interfacial friction coefficient during interaction of AZ31 B alloy with roll surfaces. When rolling at the optimum speed, the interfacial friction coefficient ranged from 0.16 to 0.58, which was strongly positively correlated with the reduction but slightly positively correlated with the initial temperature. Depended on the rolling characteristics, external friction effect coefficient ranged from 1.25 to 2.35 and it exhibited positive correlation with both the initial rolling temperature and rolling reduction.