激光方脉冲作用下强场自电离过程

本文研究了激光方脉冲作用下的强场自电离过程,从而推广了以往包含高阶离化的研究,讨论了基态布居和自电离共振线型在强场下受激光脉宽、光强的影响。结果表明,强场自电离过程及其中的高阶离化不仅与光强有关,而且还和原子与激光相互作用的时间紧密相关。

脉冲光激励对少数载流子寿命的理论分析

主要从理论上研究脉冲光信号激励对少数载流子寿命测试结果的影响.通过研究两种理想的脉冲光源——高斯脉冲、方脉冲与理想δ函数光源产生的光电导衰减曲线的对比,发现对于高斯脉冲光源,只有在脉宽的条件下才可等效于δ函数光源;而脉宽的方脉冲才能等效为δ函数光源.否则脉冲光过长的脉宽和下降沿将对光电导衰减曲线中进一步分离出的表面复合速度和少子体寿命结果造成误差.若样品受表面状况影响较小时(如体寿命较低或表面复合速度低时),则可对两种理想脉冲光源的要求适当放宽.

癌和正常细胞熵产生的差异性及其治疗意义(英文)

通过热力学计算证明通常条件下癌细胞的熵产生率高于正常细胞,熵流方向为从癌到正常组织.但在适当外场作用下,正常细胞的熵产生率可提高更多,因而可以改变熵流方向,从而抑止癌的毒性信息流的扩散.设计了可试用于癌症治疗的方脉冲电场.

Electrotransformation of Thermotoga maritima MS8

[Objective] The aim was to study on the electrotransformation of Thermotoga maritima MS8.[Method] Square waves,exponential waves and high voltage shock were used for the electrotransformation of T.maritima MS8,and the obtained transformants were detected by PCR.[Result] A single square electric pulse could be applied to cell sample in 0.2 cm ET cuvettes by using a Bio-Rad Gene Pulser set at 150 V,25 ms at room temperature,but the transformation efficiency was very low.[Conclusion] This research may improve the transformation efficiency of T.maritima MS8.

Dynamic interacting relationships among international oil prices, macroeconomic variables and precious metal prices

From the perspective of long-term and short-term, the methods of TY causality test, generalized impulse response function, variance decomposition were used to investigate the impacts of international oil prices and macroeconomic variables on Chinese gold, silver and platinum prices, but also the feedback effects of Chinese precious metal prices under this impact. The results show that international oil prices play an important role in precious metal price variation both in long-term and short-term, and exchange rate only has an effect in short-term, while interest rate is ineffective in predicting precious metal prices. In addition, precious metal prices have some feedback effects on international oil prices and interest rate in short-term.

The Global Solutions of Impulsive Retarded Functional Differential Equations

In this paper, we present some results on the existence of the golbal solutions of nonlinear impulsive retarded functional differential equations.

Gas Flow in Unilateral Opening Pulse Tubes Based on Real Gas Equation of State

The real gas effect is dominant at high pressure and low temperature, and it is modeled by complex equations of state other than perfect gas law. In the vicinity of liquid-vapor critical point, the real gas exhibits unusual gas dynamic behavior. In the present work, a transient wave fields in unilateral opening pulse tube is simulated by solving the Navier-Stokes equations incorporated with the Peng-Robinson thermodynamic model. The computational fluid dynamics （CFD） results show a remarkable deviation between perfect gas model and real gas model for contact interface and shockwave. The wave diagram based on the real gas model can help to solve the problem of offset design point.

A Fast Attack Algorithm on the MD5 Hash Function

The sufficient conditions for keeping desired differential path of MD5 was discussed. By analyzing the expanding of subtraction difference, differential characters of Boolean functions, and the differential characters of shift rotation, the sufficient conditions for keeping desired differential path could be obtained. From the differential characters of shift rotation, the lacked sufficient conditions were found. Then an algorithm that reduces the number of trials for finding collisions were presented. By restricting search space, search operation can be reduced to 2 34 for the first block and 2 30 for the second block. The whole attack on the MD5 can be accomplished within 20 hours using a PC with 1.6 G CPU.

Near-fault directivity pulse-like ground motion effect on high-speed railway bridge

The vehicle-track-bridge(VTB)element was used to investigate how a high-speed railway bridge reacted when it was subjected to near-fault directivity pulse-like ground motions.Based on the PEER NAG Strong Ground Motion Database,the spatial analysis model of a vehicle-bridge system was developed,the VTB element was derived to simulate the interaction of train and bridge,and the elasto-plastic seismic responses of the bridge were calculated.The calculation results show that girder and pier top displacement,and bending moment of the pier base increase subjected to near-fault directivity pulse-like ground motion compared to far-field earthquakes,and the greater deformation responses in near-fault shaking are associated with fewer reversed cycles of loading.The hysteretic characteristics of the pier subjected to a near-fault directivity pulse-like earthquake should be explicitly expressed as the bending moment-rotation relationship of the pier base,which is characterized by the centrally strengthened hysteretic cycles at some point of the loading time-history curve.The results show that there is an amplification of the vertical deflection in the girder's mid-span owing to the high vertical ground motion.In light of these findings,the effect of the vertical ground motion should be used to adjust the unconservative amplification constant 2/3 of the vertical-to-horizontal peak ground motion ratio in the seismic design of bridge.

Insights in active pulsing air separation technology for coarse coal slime by DEM-CFD approach

To research a novel technology for dry coarse coal slime beneficiation and extend its application, active pulsing air separation technology was investigated by DEM-CFD coupling simulation approach. The results show that the ash content of feed is reduced by 10% 15% and the organic efficiency is up to 91.78% by using the active pulsing air separation technology. The gas solid flow in the active pulsing air classifier was simulated. Meanwhile, the characteristics of particle motion and the separation process of different particles were analyzed, and the mechanical structure of the classifier was also modified to achieve high separation efficiency. Therefore, a novel high-efficiency dry beneficiation technique was advanced for coarse coal slime.

A Boundary Value Problem for Second Order Functional Differential Equations with Impulses

Aim To investigate the boundary value problem for second order functional differentiai equations with impulses. Methods The fixed point principle was used to establish our results. Results and Conclusion The results of the esistence, the uniqueness and the continuous dependence on aprameter of soiutions of the boundary value problems for second order functional differential equations with impulses are obtained.

The Existence of Solutions of Three-point Boundary Value Problems for Second Order Impulsive Differential Equation

We study the existence of solutions to the second order three-point boundary value problem：{x″（t）＋f（t,x（t）,x′（t））=0,t≠ti,△x（ti）=Ii（x（ti）,x′（ti））,i=1,2,…,k,△x′（ti）=Ji（x（ti）,x′（t））,i=1,2,…,k,x（0）=0=x（1）-αx（η）,where 0〈η〈1,α∈R,and f：[0,1]×R×R→R,Ii：R×R→R,Ji：R×R→R（i=1,2,…,k）are continuous. Our results is new and different from previous results. In particular, we obtain the Green function of the problem, which makes the problem simpler.

The value of pulse wave velocity in the diagnosis of coronary heart disease

Objective: Using receiver operating characteristics (ROC) curve to evaluate the value of pulse wave velocity (PWV) in the diagnosis of coronary heart disease (CHD). Methods: By using coronary angiography as golden diagnostic standard of CHD, 218 patients were divided into both CHD group (n=121) and non-CHD group (n = 97). All these patients received PWV test. The efficacy of PWV of each artery segments in the diagnosis of CHD was evaluated by ROC curve. The sensitivity and specificity were calculated with the golden diagnostic standard of CHD. Results:The PWV of right carotid to femoral artery (Rc-f), left carotid to femoral artery (Lc-f), right radial to carotid artery (Rc-r), left radial to carotid artery (Lc-r) in CHD group were significantly higher than that of non-CHD group (9. 31±1. 75 vs 7.60±1.59, P<0. 01; 9. 02±1.71 vs 7. 52±1.50, P<0. 01; 8. 69±1. 37 vs 8. 00±1. 27, P<0. 01; 8.52±1. 03 vs 8. 03±1. 2, P<0. 01 respectively). However, the PWV of both right and left femoral to ankle artery (Rf-a and Lf-a) had no significant differences between the two groups. We then compared the area under curve (AUC) of each ROC(AUCROC) of PWV of Rc-f, Lc-f Rc-r and Lc-r to evaluate their diagnostic efficacy for CHD. We found that AUCROC of Rc-f PWV was the biggest (AUCROC = 0. 818), at the peak point of its ROC curve, the PWV was 8. 32 m/s. PWV>8. 32 m/s of Rc-f could predict the presence of CHD with a sensitivity of 79% and specificity of 77%. Conclusion: The PWV of Rc-f, Lc-f, Rc-r, Lc-r are significantly higher in CHD group than that in non-CHD group, and PWV of Rc-f is the most accurate in the detection of CHD. The PWV>8. 32 m/s of RC-F is a valuable predictor of CHD.

Asymptotical p-Moment Stability of Stochastic Impulsive Differential Equations and Its Application in Impulsive Control

In this paper, the asymptotical p-moment stabifity of stochastic impulsive differential equations is studied, and a comparison theory to ensure the asymptotieal p-moment stability for trivial solution of this system is established, from which we can find out whether a stochastic impulsive differential system is stable just from a deterministic comparison system. As an application of this theory, we control the chaos of stochastic Chen system using impulsive method, and a stable region is deduced too. Finally, numerical simulations verify the feasibility of our method.

A novel technology of high-voltage pulse discharge for comminution of galena ore

An innovative technology of high-voltage pulse discharge(HVPD)was proposed to investigate the comminution characteristics of galena ore.The optimal experiment parameters were determined as follows:spark gap spacing of 25 mm,pulse number of 120,and voltage of 25 k V.The mass fraction with size<0.074 mm in ground products was improved by the HVPD.Meanwhile,the relative grindability declined with the increase of the grinding time,which indicated that the superiority of HVPD was weakened.The ground products of HVPD were distributed more homogeneously than those of mechanical crushing.The liberation of breakage products was improved by 24.57%via the HVPD.Moreover,the Brunauer–Emmett–Teller(BET)specific surface area,pore volume,and average pore size were increased via the HVPD.Scanning electron microscopy(SEM)and energy-dispersive X-ray spectroscopy(EDS)analyses suggested that obvious grain-boundary breakage and several stomatal traces were observed in the HVPD products.

On the Existence of Positive Solutions for Impulsive Neutral Differential Equations

Aim To investigate the existence of positive solutions for impulsive neutral differential equations. Methods The Banach contraction principle was used to establish our results. Results and Conclusion The results of the existence of positive solutions for impulsive neutral differential equations are obtained.

DC FLOW SUPPRESSION IN A SINGLE-STAGE G-M TYPE PULSE TUBE COOLER

An experimental investigation on DC flow suppression in a single-stage G-M type pulse tube cooler is made. The influence of DC flow induced by the introduction of the double-inlet on the refrigeration performance of the cooler is experimentally examined. Two parallelplaced needle valves with an opposite flow direction called as double-valved configuration, instead of conventional single-valved configuration as the double-inlet is used to reduce the DC flow. With the double-valved configuration, the minimum temperatures of 18.4 K and 14.7 K, and the cooling powers of 11.5 W and 29.5 W are also obtained by RW2 and CP4000, respectively.

ADAPTIVE HISTOGRAM-BASED FILTER FOR IMAGE RESTORATION

A novel filter for image restoration is proposed in this paper. The filter estimates histogram of original image via input image. It gets a membership function through the histogram, and the membership function contains a lot of information of original image. Then a weighted fuzzy mean filter is established based on this membership function; meanwhile, the filter adaptively adopts different filter scale according to the character divergence of image region and intensity of impulsive noise. Experimental result shows that new filter gives superior performance to conventional filters and currently used fuzzy filter.

Distant Bottom Reverberation in Shallow Water

The method of coupled mode is introduced for investigation of bi-static distant bottom reverberation of impulsive source in shallow water, which will not contradict with principle of reciprocity in all cases. And the method of multi-pole for directional source is also introduced. It shows that in case of layered medium, intensity of bi-static bottom reverberation will decease according to the cubic power of receiving time t, and the transverse spatial correlation of bottom reverberation is a little greater than longitudinal correlation for equal separation of receivers, and both vary in form with the receiving time.

Oscillation of Nonlinear Impulsive Delay Hyperbolic Partial Differential Equations

In this paper,by making use of the calculous technique and some results of the impulsive differential inequality,oscillatory properties of the solutions of certain nonlinear impulsive delay hyperbolic partial differential equations with nonlinear diffusion coefficient are investigated.Sufficient conditions for oscillations of such equations are obtained.