Effect of projectile parameters on opening behavior of PELE penetrating RC target

When a penetrator with enhanced lateral effect(PELE) impacts on a reinforced concrete(RC) target,the target is damaged with a large opening.An understanding of how PELE projectile parameters affect the opening dimension,is essential for effective design of the PELE projectile.In this study,under the condition that the impact velocity and target parameters(strength and thickness) were fixed values,the important influence factors of the PELE(jacket wall thickness B,jacket material strength Y1,filling material strength Y2 and angle of monolithic jacket θ) were determined by a dimensional analysis.Tests and simulations of the PELE penetrating the RC target were conducted to analyze the influence of these factors on opening diameter(D,an equivalent diameter under relative kinetic energy).Based on the test and simulation results,it is found that the influence of these factors B,Y1 and θ on the deformation mode of the jacket shows a similar trend:as values of the three factors decrease,the jacket deforms from small bending deformation to large one,and then to curling deformation.This causes the opening diameter to first increase with the decrease of these three factors,and then decreases.It is well known that the bending resistance of the jacket is related to these factors B,Y1 and θ.Therefore,a plastic limit bending moment(M0) of the jacket was quoted to characterize the influence of these factors on the bending deformation of the jacket and the opening diameter of the target.The influence factor Y2 causes D to first increase with the increase of Y2,and then decreases.A formula was developed to predict the opening diameter,whose influence parameters were considered in a dimensionless way.It has been shown that the dimensionless opening diameter D/d1 is dependent on two dimensionless parameters■ and■,where d1 and fc are the outer diameter of the projectile and the compressive strength of the target,respectively.

Effect of Penetration Rates on the Piezocone Penetration Test in the Yellow River Delta Silt

Partial drainage often occurs during piezocone penetration testing on Yellow River Delta silt because of its intermediate physical and mechanical properties between those of sand and clay.Yet,there is no accurate understanding for the range of penetra-tion rates to trigger the partial drainage of silt soils.In order to fully investigate cone penetration rate effects under partial drainage condi-tions,indoor 1 g penetration model tests and numerical simulations of cavity expansion at variable penetration rates were carried out on the Yellow River Delta silt.The boundary effect of the model tests and the variation of key parameters at the different cavity ex-pansion rates were analyzed.The 1 g penetration model test results and numerical simulations results consistently indicated that the penetration rate to trigger the partially drainage of typical silt varied at least three orders of magnitude.The numerical simulations also provide the reference values for the penetration resistance corresponding to zero dilation and zero viscosity at any given normalized penetration rate for silt in Yellow River Delta.These geotechnical properties can be used for the design of offshore platforms in Yel-low River Delta,and the understanding of cone penetration rate effects under the partially drained conditions would provide some technical support for geohazard evaluation of offshore platforms.

Sintering Effect on the Performance of Tungsten-copper Powder Liner

In order to study the properties of high-temperature sintered tungsten-copper powder shaped charge liner, the tungsten powder and copper powder, whose particle size is below 20 μm, were chosen as the main material. The mixed powder were directly pressed into the desired shape of the charge liner by the top direct-pressure way. The microscopic morphology of the spinning shaped charge liner, and the particle properties of the copper and tungsten powder were studied with scanning electron microscopy. The experimental results showed that the irregular copper powder and regular tungsten powder both are effectively and high- temperature sintering, which can improve the compactness of the powder liner effectively. The wall thickness and density of the no sintered and sintered liner were tested, showing that sintering thinned down the wall thickness and improved the density. The penetration depth of no sintered powder liner, sintered powder liner and the spinning copper plate liner were respectively tested in different standoff, showing that the penetration properties of sintered powder liner are well.

Magnetic field‐enhanced water splitting enabled by bifunctional molybdenum‐doped nickel sulfide on nickel foam

Herein,we report bifunctional molybdenum-doped nickel sulfide on nickel foam(Mo-NiS_(x)/NF)for magnetic field-enhanced overall water splitting under alkaline conditions.Proper doping of Mo can lead to optimization of the electronic structure of NiS_(x),which accelerates the dissociation of H2O and the adsorption of OH−in the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER)processes,respectively.In addition,the magnetically active Mo-NiS_(x)/NF can further enhance the HER and OER activity under an applied magnetic field due to the magnetoresistance effect and the ferromagnetic(FM)exchange-field penetration effect.As a result,Mo-NiS_(x)/NF requires low overpotentials of 307 mV at 50mA cm^(−2)(for OER)and 136 mV at 10mA cm^(−2)(for HER)under a magnetic field of 10000 G.Furthermore,the electrolytic cell constructed by the bifunctional Mo-NiS_(x)/NFs as both the cathode and the anode shows a low cell voltage of 1.594 V at 10 mA cm^(−2)with optimal stability over 60 h under the magnetic field.Simultaneous enhancement of the HER and OER processes by an external magnetic field through rational design of electrocatalysts might be promising for overall water splitting applications.

THE CHARACTERISTICS OF LASER GENERATED ULTRASOUND IN SOLIDS

The laser generated ultrasound in solids in a thermoelastic regime is studied by solving thermoelastic wave equations. Analytic expressions of two-dimensional far-field ultrasonic displacements including the effects of thermal diffusion and optical penetration were obtained by means of the integral transform method. The meaning of the expressions is discussed. The effects of optical absorption coefficient on the directivity of laser generated ultrasound in non-metallic solids are also discussed. The directivity patterns of both longitudinal waves and shear waves are presented.

Nanomedicine-based treatment:An emerging therapeutical strategy for pulmonary hypertension

Pulmonary hypertension(PH)can cause breathing difficulty,a rapid decline of exercise capacity,heart failure,eventually death of the patients.The latest epidemiological study demonstrates that PH has a much higher incidence than previously thought.PH is still a highly fatal disease due to the many disadvantages of the current drugs,such as short half-life,lack of targeting,potent side effects.The PH pathological features offer great opportunities for nanomedicines for PH.Recently,emerging nanomedicines demonstrated great advantages in the therapeutic effect of PH by enhancing the accumulation of drugs in PH lesion,optimizing drug efficacy,minimizing drug side effects.However,this promising field of cross-cutting research is far from being widely explored due to the huge professional barriers.To solve this problem,we provide a comprehensive review for the latest progresses of nanomedicines in the treatment of PH.Firstly,we systematical summarized the PH pathological features and the current clinical drug treatment of PH.The advantages of nanomedicines are also deeply discussed in the treatment of PH.Subsequently,we focused on the research progresses of nanomedicines in PH through three aspects:advanced nano-drug delivery system for traditional drugs and new target drugs,gene therapy-based nanomedicines,other nanomedicines for the treatment of PH.Finally,we also discussed the prospects and challenges for the clinical application of nanomedicines in PH,provided directions for the research and development of nanomedicines for PH treatment in the future.