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A Novel Facial Cream Based on Skin Penetrable Hemp Oil Microparticles
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作者 Rachel Lubart Inbar Yariv +3 位作者 Dror Fixler Ayelet Rothstein Arie Gruzman Anat Lipovsky 《Journal of Cosmetics, Dermatological Sciences and Applications》 2023年第3期165-178,共14页
Objective: Hemp seed oil is perfect for most skin types;it moisturizes skin and protects it from inflammation, oxidation, and other causes of aging. The problem is that the Hemp oil-based products do not penetrate the... Objective: Hemp seed oil is perfect for most skin types;it moisturizes skin and protects it from inflammation, oxidation, and other causes of aging. The problem is that the Hemp oil-based products do not penetrate the skin;they remain on the skin’s surface. Recently researchers have been trying to prepare nano emulsions of hemp oil to facilitate its permeation to deep skin layers. In all techniques used today, surfactants are added to the emulsification process. These surfactants may cause unwanted skin side effects. In the present study, we prepare micronized Hemp (m-Hemp) without using any surfactants in the micronization process, thus avoiding the side effects associated with surfactant addition. Methods & Results: Particles size of m-Hemp was evaluated using electron microscopy. Various sizes of m-Hemp were found, the smallest being 100 nm in diameter. The antioxidation properties of m-Hemp were measured using the Electron Spin Resonance (ESR) technique and were found to be enhanced. Skin topography and morphology following a cream containing m-Hemp treatment were visualized by Optical Profilometry and ESEM respectively. The results show a marked improvement in skin topography in all measured parameters. In addition, human keratinocytes (HaCaT) were exposed to inflammatory conditions and were then treated using Hemp. As a result, one of the key inflammatory factors (IL-2) was significantly reduced after treatment with m-Hemp (p ≤ 0.0001). The skin penetration of the cream containing m-Hemp was tested on human skin using the IMOPE (Iterative Multi-plane Optical Property Extraction) system. The results indicate that m-Hemp penetrates both the stratum corneum and the deep epidermal layers towards the dermis. Conclusion: The new cream prepared with micronized Hemp shows significant anti-inflammatory and antioxidative effects and demonstrates the entrance of m-Hemp to the skin epidermal layer. 展开更多
关键词 HEMP MICROPARTICLES ANTI-INFLAMMATORY ANTIOXIDANT Skin Penetration
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Automatic radar antenna scan type recognition based on limited penetrable visibility graph 被引量:2
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作者 LIU Songtao LEI Zhenshuo +1 位作者 GE Yang WEN Zhenming 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2021年第2期437-446,共10页
To address the problem of the weak anti-noise and macro-trend extraction abilities of the current methods for identifying radar antenna scan type,a recognition method for radar antenna scan types based on limited pene... To address the problem of the weak anti-noise and macro-trend extraction abilities of the current methods for identifying radar antenna scan type,a recognition method for radar antenna scan types based on limited penetrable visibility graph(LPVG)is proposed.Firstly,seven types of radar antenna scans are analyzed,which include the circular scan,sector scan,helical scan,raster scan,conical scan,electromechanical hybrid scan and two-dimensional electronic scan.Then,the time series of the pulse amplitude in the radar reconnaissance receiver is converted into an LPVG network,and the feature parameters are extracted.Finally,the recognition result is obtained by using a support vector machine(SVM)classifier.The experimental results show that the recognition accuracy and noise resistance of this new method are improved,where the average recognition accuracy for radar antenna type is at least 90%when the signalto-noise ratio(SNR)is 5 dB and above. 展开更多
关键词 antenna scan type limited penetrable visibility graph(LPVG) support vector machine(SVM) cognitive electronic warfare
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INVERSE SCATTERING BY AN INHOMOGENEOUS PENETRABLE OBSTACLE IN A PIECEWISE HOMOGENEOUS MEDIUM 被引量:1
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作者 刘晓东 张波 《Acta Mathematica Scientia》 SCIE CSCD 2012年第4期1281-1297,共17页
This paper is concerned with the inverse problem of scattering of time-harmonic acoustic waves by an inhomogeneous penetrable obstacle in a piecewise homogeneous medium. The well-posedness of the direct problem is fir... This paper is concerned with the inverse problem of scattering of time-harmonic acoustic waves by an inhomogeneous penetrable obstacle in a piecewise homogeneous medium. The well-posedness of the direct problem is first established by using the integral equation method. We then proceed to establish two tools that play important roles for the inverse problem: one is a mixed reciprocity relation and the other is a priori estimates of the solution on some part of the interfaces between the layered media. For the inverse problem, we prove in this paper that both the penetrable interfaces and the possible inside inhomogeneity can be uniquely determined from a knowledge of the far field pattern for incident plane waves. 展开更多
关键词 UNIQUENESS piecewise homogeneous medium penetrable obstacle uniquecontinuation principle Holmgren's uniqueness theorem inverse scattering
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Some properties on far-field pattern of scattering by penetrable obstacle in ocean waveguide
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作者 潘文峰 尤云祥 +1 位作者 缪国平 李卓球 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2008年第2期239-250,共12页
This paper is concerned with the properties of propagation fax-field patterns corresponding to the scattering of time harmonic acoustic waves by a bounded penetrable obstacle in an ocean waveguide. The sets of solutio... This paper is concerned with the properties of propagation fax-field patterns corresponding to the scattering of time harmonic acoustic waves by a bounded penetrable obstacle in an ocean waveguide. The sets of solutions to the transmission problem are constructed such that the restriction of these solutions to the boundary of the penetrable obstacle is dense in a Hilbert space. Then conditions under which a set of propagation far-field patterns is complete in a Hilbert space are determined. These properties are important in investigating inverse transmission problems in an ocean waveguide. 展开更多
关键词 oceanic waveguide penetrable object far-field pattern COMPLETENESS denseness
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Coupled Perturbed Modes over Sloping Penetrable Bottom
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作者 朱飞龙 Eric I. Thorsos 李风华 《Chinese Physics Letters》 SCIE CAS CSCD 2017年第7期126-129,共4页
In environments with water depth variations, one-way modal solutions involve mode coupling. Higham and Tindle developed an accurate and fast approach using perturbation theory to locally determine the change in mode f... In environments with water depth variations, one-way modal solutions involve mode coupling. Higham and Tindle developed an accurate and fast approach using perturbation theory to locally determine the change in mode functions at steps. The method of Higham and Tindle is limited to low frequency (≤250 Hz). We extend the coupled perturbation method, thus it can be applied to higher frequencies. The approach is described and some examples are given. 展开更多
关键词 Coupled Perturbed Modes over Sloping penetrable Bottom
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CYCLIC HARDENING BEHAVIOR OF POLYCRYSTALS WITH PENETRABLE GRAIN BOUNDARIES:TWO-DIMENSIONAL DISCRETE DISLOCATION DYNAMICS SIMULATION 被引量:2
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作者 Chuantao Hou Zhenhuan Li Minsheng Huang Chaojun Ouyang 《Acta Mechanica Solida Sinica》 SCIE EI 2009年第4期295-306,共12页
A two-dimensional discrete dislocation dynamics (DDD) technology by Giessen and Needleman (1995), which has been extended by integrating a dislocation-grain boundary interaction model, is used to computationally a... A two-dimensional discrete dislocation dynamics (DDD) technology by Giessen and Needleman (1995), which has been extended by integrating a dislocation-grain boundary interaction model, is used to computationally analyze the micro-cyclic plastic response of polycrystals containing micron-sized grains, with special attentions to significant influence of dislocationpenetrable grain boundaries (GBs) on the micro-plastic cyclic responses of polycrystals and underlying dislocation mechanism. Toward this end, a typical polycrystalline rectangular specimen under simple tension-compression loading is considered. Results show that, with the increase of cycle accumulative strain, continual dislocation accumulation and enhanced dislocation-dislocation interactions induce the cyclic hardening behavior; however, when a dynamic balance among dislocation nucleation, penetration through GB and dislocation annihilation is approximately established, cyclic stress gradually tends to saturate. In addition, other factors, including the grain size, cyclic strain amplitude and its history, also have considerable influences on the cyclic hardening and saturation. 展开更多
关键词 discrete dislocation dynamics simulation cyclic micro-plasticity size effect POLYCRYSTALS grain boundary penetrability
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A penetrable interactive 3D display based on motion recognition(Invited Paper) 被引量:1
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作者 苏忱 夏新星 +4 位作者 李海峰 刘旭 匡翠方 夏军 王保平 《Chinese Optics Letters》 SCIE EI CAS CSCD 2014年第6期26-29,共4页
Based on light field reconstruction and motion recognition technique, a penetrable interactive floating 3D display system is proposed. The system consists of a high-frame-rate projector, a flat directional diffusing s... Based on light field reconstruction and motion recognition technique, a penetrable interactive floating 3D display system is proposed. The system consists of a high-frame-rate projector, a flat directional diffusing screen, a high-speed data transmission module, and a Kinect somatosensory device. The floating occlusioncorrect 3D image could rotate around some axis at different speeds according to user's hand motion. Eight motion directions and speed are detected accurately, and the prototype system operates efficiently with a recognition accuracy of 90% on average. 展开更多
关键词 A penetrable interactive 3D display based on motion recognition HIGH DMD
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Ballistic performance of spherical fragments penetrating PCrNi3MoV target plates
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作者 Dou Hong Wenbin Li +3 位作者 Yu Zheng Yiming Li Ning Jiang Kebin Zhang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第3期295-307,共13页
PCrNi3MoV steel is a medium-carbon,low-alloy quenched and tempered steel that finds its applications in military gun barrels due to the high wear resistance and ablation resistance.To study the penetration and failure... PCrNi3MoV steel is a medium-carbon,low-alloy quenched and tempered steel that finds its applications in military gun barrels due to the high wear resistance and ablation resistance.To study the penetration and failure modes of PCrNi3MoV plates impacted by tungsten spheres,tungsten spheres of various diameters(5 mm,8 mm,and 10 mm)were used to impact PCrNi3MoV steel plates with thicknesses of 6 mm,9 mm,and 14 mm.The penetration performance of the spheres was analyzed for different velocities,and the ultimate penetration velocity of the plate was obtained.It was found that the primary failure modes of the PCrNi3MoV plate were compression pitting failure and shear failure.Using the dimensional analysis method,a relationship between the bulge height of the steel plate and the fragment velocity,an equation for the ultimate penetration velocity,and a relationship between the target penetration energy and the fragment velocity were obtained.Then,a projectile-target action index was proposed to describe the process of tungsten spheres with different velocities impacting target plates.The results suggested that under the same thickness of the target plate,a larger-diameter fragment required more kinetic energy to obtain the same ultimate penetration effect as a smaller-diameter fragment.The equations obtained through dimensional analysis predicted values that agreed well with experimental values,indicating that these equations can be applied to engineering applications. 展开更多
关键词 Impact damage Ultimate penetration velocity Bulge height Target penetration energy Failure modes
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Formation behaviors of rod-like reactive shaped charge penetrator and their effects on damage capability
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作者 Tao Sun Haifu Wang +4 位作者 Shipeng Wang Chao Ge Die Hu Pengwan Chen Yuanfeng Zheng 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第2期242-253,共12页
Formation behaviors of rod-like reactive shaped charge penetrator(RRSCP)and their effects on damage capability are investigated by experiments and numerical simulations.The pulsed X-ray technology and a spaced aluminu... Formation behaviors of rod-like reactive shaped charge penetrator(RRSCP)and their effects on damage capability are investigated by experiments and numerical simulations.The pulsed X-ray technology and a spaced aluminum/steel plate with the thicknesses of 5 mm/100 mm are used.Three types of sphericalsegment aluminum-polytetrafluoroethylene-copper(Al-PTFE-Cu)reactive liners with Cu contents of 0%,46.6%,and 66%are fabricated and tested.The experimental results show that the reactive liners can form excellent rod-shaped penetrators with tail skirts under the shaped charge effect,but the tail skirts disappear over time.Moreover,rupturing damage to the aluminum plate and penetration to the steel plate are caused by the RRSCP impact.From simulation analysis,the RRSCP is formed by a mechanically and chemically coupled response with the reactive liner activated by shock in its outer walls and bottom and then backward overturning,forming a leading reactive penetrator and a following chemical energy cluster.The unique formation structure determines the damage modes of the aluminum plate and the steel plate.Further analysis indicates that the formation behaviors and damage capability of Al-PTFE-Cu RRSCP strongly depend on Cu content.With increasing Cu content,the velocity,activation extent,and reaction extent of Al-PTFE-Cu RRSCP decrease,which contribute to elongation and alleviate the negative effects of chemical reactions on elongation,significantly increasing the length-diameter ratio and thus enhancing the capability of steel plate penetration.However,the lower activation extent and energetic density will weaken the RRSCP's capability of causing rupturing damage to the aluminum plate. 展开更多
关键词 Reactive materials Al-PTFE composites Reactive liner X-ray PENETRATION
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Jet formation and penetration performance of a double-layer charge liner with chemically-deposited tungsten as the inner liner
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作者 Bihui Hong Wenbin Li +2 位作者 Yiming Li Zhiwei Guo Binyou Yan 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第3期374-385,共12页
This paper proposes a type of double-layer charge liner fabricated using chemical vapor deposition(CVD)that has tungsten as its inner liner.The feasibility of this design was evaluated through penetration tests.Double... This paper proposes a type of double-layer charge liner fabricated using chemical vapor deposition(CVD)that has tungsten as its inner liner.The feasibility of this design was evaluated through penetration tests.Double-layer charge liners were fabricated by using CVD to deposit tungsten layers on the inner surfaces of pure T2 copper liners.The microstructures of the tungsten layers were analyzed using a scanning electron microscope(SEM).The feasibility analysis was carried out by pulsed X-rays,slug-retrieval test and static penetration tests.The shaped charge jet forming and penetration law of inner tungsten-coated double-layer liner were studied by numerical simulation method.The results showed that the double-layer liners could form well-shaped jets.The errors between the X-ray test results and the numerical results were within 11.07%.A slug-retrieval test was found that the retrieved slug was similar to a numerically simulated slug.Compared with the traditional pure copper shaped charge jet,the penetration depth of the double-layer shaped charge liner increased by 11.4% and>10.8% respectively.In summary,the test results are good,and the numerical simulation is in good agreement with the test,which verified the feasibility of using the CVD method to fabricate double-layer charge liners with a high-density and high-strength refractory metal as the inner liner. 展开更多
关键词 Shaped charge Chemical vapor deposition TUNGSTEN Double-layer charge liner X-ray PENETRATION
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Reply to the note by Li Piani et al.
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作者 T.Li Piani J.Weerheijm L.J.Sluys 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第1期603-606,共4页
In 2017,a ballistic phenomenological model was proposed by the authors of Ref.[1] to numerically simulate the experimental depths of small caliber projectiles impacting walls made of adobe.The opportunity for a new mo... In 2017,a ballistic phenomenological model was proposed by the authors of Ref.[1] to numerically simulate the experimental depths of small caliber projectiles impacting walls made of adobe.The opportunity for a new model in the field revealed from the observation that two older models recently used by the authors of Ref.[2] shared a linear relationship between the penetration depth P and the impacting velocity v_(O). 展开更多
关键词 PENETRATION ADOBE Modeling
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Research on the influences of motion characteristics of jetting projectile charge under water
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作者 Xing Chen Yong-gang Lu 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第3期411-425,共15页
Shaped charge warhead is important for enhancing the damage performance of underwater weapons.This paper used finite element analysis software and based on JPC water penetration experiments to examine the influence of... Shaped charge warhead is important for enhancing the damage performance of underwater weapons.This paper used finite element analysis software and based on JPC water penetration experiments to examine the influence of liner parameters(wall thickness,material),charge aspect ratio,and stand-off distance on the movement characteristics of JPC in water.The findings reveal that the head diameter of the JPC increases and experiences significant erosion after entering the water,the effective length of the JPC in water undergoes two distinct phases:a growth phase and a decrease phase,with the velocity of the JPC decaying exponentially.Increasing the liner thickness,stand-off distance and the charge aspect ratio can improve the erosion resistance and the velocity retention capacity of the JPC.The optimal ranges for liner thickness and stand-off distance are 0.0363D_(k) to 0.0545D_(k)(D_(k) is the charge diameter),the stand-off distance should be within 1.0D_(k).After the charge aspect ratio higher than 1.25,the charge structure exerts minimal influence the movement characteristics of the JPC in water.Material density plays a crucial role in the velocity decay pattern of the JPC during penetration.JPC with higher densities exhibit superior velocity retention capabilities in water,with the velocity decay pattern converging if the densities are similar.Consequently,copper,tantalum and tungsten liners are deemed appropriate for underwater shaped charge warhead.Finally,the results will provide an important reference for the design of underwater shaped charge warhead. 展开更多
关键词 JPC Movement characteristics Underwater penetration Numerical simulation
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Numerical investigation of sinusoidal pulsating gas intake to intensify the gas-slag momentum transfer in the top-blown smelting furnace
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作者 Zhanghao Wan Shiliang Yang +3 位作者 Desong Kong Dongbo Li Jianhang Hu Hua Wang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第2期301-314,共14页
The variation characteristics of bubble morphology and the thermal-physical properties of bubble boundary in the top-blown smelting furnace were explored by means of the computational fluid dynamics method.The essenti... The variation characteristics of bubble morphology and the thermal-physical properties of bubble boundary in the top-blown smelting furnace were explored by means of the computational fluid dynamics method.The essential aspects of the fluid phase(e.g.,splashing volume,dead zone of copper slag,and gas penetration depth)were explored together with the effect of sinusoidal pulsating gas intake on the momentum-transfer performance between phases.The results illustrated that two relatively larger vortices and two smaller vortices appear in the bubble waist and below the lance,respectively.The expansion of larger ones as well as the shrinking of smaller ones combine to cause the contraction of the bubble waist.Compared to the results of the case with a fixed gas injection velocity(V_(g)=58 m/s),the splashing volume and dead zone volume of the slag under the V_(g)=58+10sin(2πt)condition are reduced by 24.9%and 23.5%,respectively,where t represents the instant time.Gas penetration depth and slag motion velocity of the latter are 1.03 and 1.31 times high-er than those of the former,respectively. 展开更多
关键词 top-blown smelting furnace pulsed flow volume of fluid penetration depth splashing volume
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Energy dissipation mechanism and ballistic characteristic optimization in foam sandwich panels against spherical projectile impact
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作者 Jianqiang Deng Tao Liu +4 位作者 Liming Chen Xin Pan Jingzhe Wang Shaowei Zhu Weiguo Li 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第5期108-122,共15页
This study systematically examines the energy dissipation mechanisms and ballistic characteristics of foam sandwich panels(FSP)under high-velocity impact using the explicit non-linear finite element method.Based on th... This study systematically examines the energy dissipation mechanisms and ballistic characteristics of foam sandwich panels(FSP)under high-velocity impact using the explicit non-linear finite element method.Based on the geometric topology of the FSP system,three FSP configurations with the same areal density are derived,namely multi-layer,gradient core and asymmetric face sheet,and three key structural parameters are identified:core thickness(t_(c)),face sheet thickness(t_(f))and overlap face/core number(n_(o)).The ballistic performance of the FSP system is comprehensively evaluated in terms of the ballistic limit velocity(BLV),deformation modes,energy dissipation mechanism,and specific penetration energy(SPE).The results show that the FSP system exhibits a significant configuration dependence,whose ballistic performance ranking is:asymmetric face sheet>gradient core>multi-layer.The mass distribution of the top and bottom face sheets plays a critical role in the ballistic resistance of the FSP system.Both BLV and SPE increase with tf,while the raising tcor noleads to an increase in BLV but a decrease in SPE.Further,a face-core synchronous enhancement mechanism is discovered by the energy dissipation analysis,based on which the ballistic optimization procedure is also conducted and a design chart is established.This study shed light on the anti-penetration mechanism of the FSP system and might provide a theoretical basis for its engineering application. 展开更多
关键词 Sandwich panel Numerical simulation Ballistic resistance Specific penetration energy Energy analysis
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αDecay in extreme laser fields within a deformed Gamow-like model
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作者 Qiong Xiao Jun-Hao Cheng +3 位作者 Yang-Yang Xu You-Tian Zou Jun-Gang Deng Tong-Pu Yu 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第2期131-144,共14页
In this study, the effect of extreme laser fields on the α decay process of ground-state even–even nuclei was investigated.Using the deformed Gamow-like model, we found that state-of-the-art lasers can cause a sligh... In this study, the effect of extreme laser fields on the α decay process of ground-state even–even nuclei was investigated.Using the deformed Gamow-like model, we found that state-of-the-art lasers can cause a slight change in the α decay penetration probability of most nuclei. In addition, we studied the correlation between the rate of change of the α decay penetration probability and angle between the directions of the laser electric field and α particle emission for different nuclei. Based on this correlation, the average effect of extreme laser fields on the half-life of many nuclei with arbitrary α particle emission angles was calculated. The calculations show that the laser suppression and promotion effects on the α decay penetration probability of the nuclei population with completely random α particle-emission directions are not completely canceled.The remainder led to a change in the average penetration probability of the nuclei. Furthermore, the possibility of achieving a higher average rate of change by altering the spatial shape of the laser is explored. We conclude that circularly polarized lasers may be helpful in future experiments to achieve a more significant average rate of change of the α decay half-life of the nuclei population. 展开更多
关键词 αDecay Deformed Gamow-like model HALF-LIVES Extreme laser field Penetration probability
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High-speed penetration of ogive-nose projectiles into thick concrete targets:Tests and a projectile nose evolution model
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作者 Xu Li Yan Liu +4 位作者 Junbo Yan Zhenqing Shi Hongfu Wang Yingliang Xu Fenglei Huang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第2期553-571,共19页
The majority of the projectiles used in the hypersonic penetration study are solid flat-nosed cylindrical projectiles with a diameter of less than 20 mm.This study aims to fill the gap in the experimental and analytic... The majority of the projectiles used in the hypersonic penetration study are solid flat-nosed cylindrical projectiles with a diameter of less than 20 mm.This study aims to fill the gap in the experimental and analytical study of the evolution of the nose shape of larger hollow projectiles under hypersonic penetration.In the hypersonic penetration test,eight ogive-nose AerMet100 steel projectiles with a diameter of 40 mm were launched to hit concrete targets with impact velocities that ranged from 1351 to 1877 m/s.Severe erosion of the projectiles was observed during high-speed penetration of heterogeneous targets,and apparent localized mushrooming occurred in the front nose of recovered projectiles.By examining the damage to projectiles,a linear relationship was found between the relative length reduction rate and the initial kinetic energy of projectiles in different penetration tests.Furthermore,microscopic analysis revealed the forming mechanism of the localized mushrooming phenomenon for eroding penetration,i.e.,material spall erosion abrasion mechanism,material flow and redistribution abrasion mechanism and localized radial upsetting deformation mechanism.Finally,a model of highspeed penetration that included erosion was established on the basis of a model of the evolution of the projectile nose that considers radial upsetting;the model was validated by test data from the literature and the present study.Depending upon the impact velocity,v0,the projectile nose may behave as undistorted,radially distorted or hemispherical.Due to the effects of abrasion of the projectile and enhancement of radial upsetting on the duration and amplitude of the secondary rising segment in the pulse shape of projectile deceleration,the predicted DOP had an upper limit. 展开更多
关键词 High-speed penetration Concrete target EROSION Projectile nose evolution model
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Error field penetration in J-TEXT tokamak based on two-fluid drift-MHD model
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作者 王文 徐涛 +1 位作者 张仪 the J-TEXT team 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期545-551,共7页
An externally generated resonant magnetic perturbation can induce complex non-ideal MHD responses in their resonant surfaces.We have studied the plasma responses using Fitzpatrick's improved two-fluid model and pr... An externally generated resonant magnetic perturbation can induce complex non-ideal MHD responses in their resonant surfaces.We have studied the plasma responses using Fitzpatrick's improved two-fluid model and program LAYER.We calculated the error field penetration threshold for J-TEXT.In addition,we find that the island width increases slightly as the error field amplitude increases when the error field amplitude is below the critical penetration value.However,the island width suddenly jumps to a large value because the shielding effect of the plasma against the error field disappears after the penetration.By scanning the natural mode frequency,we find that the shielding effect of the plasma decreases as the natural mode frequency decreases.Finally,we obtain the m/n=2/1 penetration threshold scaling on density and temperature. 展开更多
关键词 plasma responses drift-MHD model error field penetration
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Interpretation and characterization of rate of penetration intelligent prediction model
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作者 Zhi-Jun Pei Xian-Zhi Song +3 位作者 Hai-Tao Wang Yi-Qi Shi Shou-Ceng Tian Gen-Sheng Li 《Petroleum Science》 SCIE EI CAS CSCD 2024年第1期582-596,共15页
Accurate prediction of the rate of penetration(ROP)is significant for drilling optimization.While the intelligent ROP prediction model based on fully connected neural networks(FNN)outperforms traditional ROP equations... Accurate prediction of the rate of penetration(ROP)is significant for drilling optimization.While the intelligent ROP prediction model based on fully connected neural networks(FNN)outperforms traditional ROP equations and machine learning algorithms,its lack of interpretability undermines its credibility.This study proposes a novel interpretation and characterization method for the FNN ROP prediction model using the Rectified Linear Unit(ReLU)activation function.By leveraging the derivative of the ReLU function,the FNN function calculation process is transformed into vector operations.The FNN model is linearly characterized through further simplification,enabling its interpretation and analysis.The proposed method is applied in ROP prediction scenarios using drilling data from three vertical wells in the Tarim Oilfield.The results demonstrate that the FNN ROP prediction model with ReLU as the activation function performs exceptionally well.The relative activation frequency curve of hidden layer neurons aids in analyzing the overfitting of the FNN ROP model and determining drilling data similarity.In the well sections with similar drilling data,averaging the weight parameters enables linear characterization of the FNN ROP prediction model,leading to the establishment of a corresponding linear representation equation.Furthermore,the quantitative analysis of each feature's influence on ROP facilitates the proposal of drilling parameter optimization schemes for the current well section.The established linear characterization equation exhibits high precision,strong stability,and adaptability through the application and validation across multiple well sections. 展开更多
关键词 Fully connected neural network Explainable artificial intelligence Rate of penetration ReLU active function Deep learning Machine learning
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A multi-source information fusion layer counting method for penetration fuze based on TCN-LSTM
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作者 Yili Wang Changsheng Li Xiaofeng Wang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第3期463-474,共12页
When employing penetration ammunition to strike multi-story buildings,the detection methods using acceleration sensors suffer from signal aliasing,while magnetic detection methods are susceptible to interference from ... When employing penetration ammunition to strike multi-story buildings,the detection methods using acceleration sensors suffer from signal aliasing,while magnetic detection methods are susceptible to interference from ferromagnetic materials,thereby posing challenges in accurately determining the number of layers.To address this issue,this research proposes a layer counting method for penetration fuze that incorporates multi-source information fusion,utilizing both the temporal convolutional network(TCN)and the long short-term memory(LSTM)recurrent network.By leveraging the strengths of these two network structures,the method extracts temporal and high-dimensional features from the multi-source physical field during the penetration process,establishing a relationship between the multi-source physical field and the distance between the fuze and the target plate.A simulation model is developed to simulate the overload and magnetic field of a projectile penetrating multiple layers of target plates,capturing the multi-source physical field signals and their patterns during the penetration process.The analysis reveals that the proposed multi-source fusion layer counting method reduces errors by 60% and 50% compared to single overload layer counting and single magnetic anomaly signal layer counting,respectively.The model's predictive performance is evaluated under various operating conditions,including different ratios of added noise to random sample positions,penetration speeds,and spacing between target plates.The maximum errors in fuze penetration time predicted by the three modes are 0.08 ms,0.12 ms,and 0.16 ms,respectively,confirming the robustness of the proposed model.Moreover,the model's predictions indicate that the fitting degree for large interlayer spacings is superior to that for small interlayer spacings due to the influence of stress waves. 展开更多
关键词 Penetration fuze Temporal convolutional network(TCN) Long short-term memory(LSTM) Layer counting Multi-source fusion
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Numerical Simulation of Slurry Diffusion in Fractured Rocks Considering a Time-Varying Viscosity
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作者 Lei Zhu Bin Liu +3 位作者 Xuewei Liu Wei Deng Wenjie Yao Ying Fan 《Fluid Dynamics & Materials Processing》 EI 2024年第2期401-427,共27页
To analyze the effects of a time-varying viscosity on the penetration length of grouting,in this study cement slur-ries with varying water-cement ratios have been investigated using the Bingham’sfluidflow equation and ... To analyze the effects of a time-varying viscosity on the penetration length of grouting,in this study cement slur-ries with varying water-cement ratios have been investigated using the Bingham’sfluidflow equation and a dis-crete element method.Afluid-solid coupling numerical model has been introduced accordingly,and its accuracy has been validated through comparison of theoretical and numerical solutions.For different fracture forms(a single fracture,a branch fracture,and a fracture network),the influence of the time-varying viscosity on the slurry length range has been investigated,considering the change in the fracture aperture.The results show that under different fracture forms and the same grouting process conditions,the influence of the time-varying viscosity on the seepage length is 0.350 m. 展开更多
关键词 Time-varying viscosity binghamfluids UDEC numerical simulation grout penetration length aperture
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