A high-density tungsten-zirconium-titanium(W-Zr-Ti)reactive alloy was prepared by powder metallurgy.This alloy exhibits high density,high strength,and violent energy release characteristics,resulting in outstanding pe...A high-density tungsten-zirconium-titanium(W-Zr-Ti)reactive alloy was prepared by powder metallurgy.This alloy exhibits high density,high strength,and violent energy release characteristics,resulting in outstanding penetration and ignition abilities.Dynamic impact experiment demonstrated its strain rate hardening effect,and the energetic characteristics were investigated by digital image processing technique and thermal analysis experiment.The results show that W-Zr-Ti reactive alloy performs compressive strength of 2.25 GPa at 5784 s^(-1)strain rate,and its exothermic reaction occurs at about 961 K.Based on the explosion test and shock wave theory,thresholds of enhanced damage effect are less than 35.77 GPa and 5.18×10^(4)kJ/m^(2)for shock pressure and energy,respectively.Furthermore,the transformation of fracture behavior and failure mechanism is revealed,which causes the increase in compressive strength and reaction intensity under dynamic loading.展开更多
In this study, to meet the development and application requirements for high-strength and hightoughness energetic structural materials, a representative volume element of a TA15 matrix embedded with a TaZrNb sphere wa...In this study, to meet the development and application requirements for high-strength and hightoughness energetic structural materials, a representative volume element of a TA15 matrix embedded with a TaZrNb sphere was designed and fabricated via diffusion bonding. The mechanisms of the microstructural evolution of the TaZrNb/TA15 interface were investigated via SEM, EBSD, EDS, and XRD.Interface mechanical property tests and in-situ tensile tests were conducted on the sphere-containing structure, and an equivalent tensile-strength model was established for the structure. The results revealed that the TA15 titanium alloy and joint had high density and no pores or cracks. The thickness of the planar joint was approximately 50-60 μm. The average tensile and shear strengths were 767 MPa and 608 MPa, respectively. The thickness of the spherical joint was approximately 60 μm. The Zr and Nb elements in the joint diffused uniformly and formed strong bonds with Ti without forming intermetallic compounds. The interface exhibited submicron grain refinement and a concave-convex interlocking structure. The tensile fracture surface primarily exhibited intergranular fracture combined with some transgranular fracture, which constituted a quasi-brittle fracture mode. The shear fracture surface exhibited brittle fracture with regular arrangements of furrows. Internal fracture occurred along the spherical interface, as revealed by advanced in-situ X-ray microcomputed tomography. The experimental results agreed well with the theoretical predictions, indicating that the high-strength interface contributes to the overall strength and toughness of the sphere-containing structure.展开更多
Predictions of extreme near-field blast wave for cylindrical charge is crucial for designing sympathetic detonation protection structures,yet the quantitative analysis of detonation products and shock wave field are s...Predictions of extreme near-field blast wave for cylindrical charge is crucial for designing sympathetic detonation protection structures,yet the quantitative analysis of detonation products and shock wave field are still insufficient.The present work conducted experiments and numerical simulations of nearfield explosion for kilogram scale cylindrical charge,and investigated the propagation and spatial distribution characteristics of incident and reflected blast waves.The results show that near-field reflected overpressure exhibits multi-peak structures,which are primarily governed by reflections of detonation products and shock wave.The reflected peak overpressure dominated by detonation products shows higher sensitivity to scaled distance.Meanwhile,the Rayleigh-Taylor instability(RTI)effect induces the evolutions of detonation products and shock wave interface from smooth to random microjets,increasing dispersion of secondary re flected peak overpressure.In free-field explosion,the incident peak overpressure exhibits a dual-peak structure,governed by the shock wave front and detonation products flowing past the gauge points.The incident peak overpressure dominated by detonation products is sensitive to orientations due to the charge structures.As the aspect ratio of charge increases from 0.6 to 8,the dominant radial azimuth angle region expands from 60°-90°to 30°-90°.An empirical model was developed to predict the spatial distributions of incident peak loads at arbitrary orientations for cylindrical charge with 0.6≤L/D≤8.0 and 0.06 m·kg^(-1/3)展开更多
Considering the characteristics of deep thick top coal roadway,in which the high ground stress,coal seam with low strength,and a large range of surrounding rock fragmentation,the pressure relief anchor box beam suppor...Considering the characteristics of deep thick top coal roadway,in which the high ground stress,coal seam with low strength,and a large range of surrounding rock fragmentation,the pressure relief anchor box beam support system with high strength is developed.The high-strength bearing characteristics and coupling yielding support mechanism of this support system are studied by the mechanical tests of composite members and the combined support system.The test results show that under the coupling effect of support members,the peak stress of the box-shaped support beam in the anchor box beam is reduced by 21.9%,and the average deformation is increased by 135.0%.The ultimate bending bearing capacity of the box-shaped support beam is 3.5 times that of traditional channel beam.The effective compressive stress zone applied by the high prestressed cable is expanded by 26.4%.On this basis,the field support comparison test by the anchor channel beam,the anchor I-shaped beam and the anchor box beam are carried out.Compared with those of the previous two,the surrounding rock convergence of the latter is decreased by 41.2%and 22.2%,respectively.The field test verifies the effectiveness of the anchor box beam support system.展开更多
The new CL-20(hexanitrohexaazaisowurtzitane)type aluminized explosives in the overdrive detonation(ODD)conditions of the core problem is how to accurately represent the state of the overdrive detonation products.To th...The new CL-20(hexanitrohexaazaisowurtzitane)type aluminized explosives in the overdrive detonation(ODD)conditions of the core problem is how to accurately represent the state of the overdrive detonation products.To this end,this paper is based on the impedance matching method to test the ODD conditions of CL-20 type aluminium explosive particle velocity.Calculated the interfacial pressure of the shock wave in different media.Determined the characteristic parameters of the reaction zone of the detonation of CL-20 aluminized explosives.Calibrated the parameters of the JoneseWilkinseLee(JWL)+γ equation for the detonation products(DPs).Revealed the effect of different DPs equation of state(EOS)on the Hugoniot pressure of ODD.The results indicate that when the content of aluminum powder ranges from 0%to 30%,the duration of the ODD reaction zone and the width of the detonation reaction zone of the CL-20-based aluminized explosive are directly proportional to the content of aluminum powder.The width of the detonation reaction zone is increased by 1.97 times to 2.7 times compared to that of the reaction zone without the addition of aluminum powder.However,the energy release efficiency of the detonation reaction zone is inversely proportional to the content of aluminum powder.When the aluminum powder content was held constant,the incorporation of AP caused a 25%reduction in the energy release efficiency of the detonation reaction zone.Compared with existing ODD state equations,the JWL +γ equation is superior in calibrating overpressure Hugoniot data and the isentropic expansion in the C-J state.The deviation between calculated pressure results and experimental measurements is within 6%.展开更多
Garnet Li_(7)La_(3)Zr_(2)O_(12)(LLZO)electrolytes have been recognized as a promising candidate to replace liquid/molten-state electrolytes in battery applications due to their exceptional performance,particularly Ga-...Garnet Li_(7)La_(3)Zr_(2)O_(12)(LLZO)electrolytes have been recognized as a promising candidate to replace liquid/molten-state electrolytes in battery applications due to their exceptional performance,particularly Ga-doped LLZO(LLZGO),which exhibits high ionic conductivity.However,the limited size of the Liþtransport bottleneck restricts its high-current discharging performance.The present study focuses on the synthesis of Ga^(3+)þand Ba^(2+)þco-doped LLZO(LLZGBO)and investigates the influence of doping contents on the morphology,crystal structure,Liþtransport bottleneck size,and ionic conductivity.In particular,Ga_(0.32)Ba_(0.15)exhibits the highest ionic conductivity(6.11E-2 S cm^(-1) at 550 C)in comparison with other compositions,which can be attributed to its higher-energy morphology,larger bottleneck and unique Liþtransport channel.In addition to Ba^(2+),Sr^(2+)þand Ca^(2+)have been co-doped with Ga3þinto LLZO,respectively,to study the effect of doping ion radius on crystal structures and the properties of electrolytes.The characterization results demonstrate that the easier Liþtransport and higher ionic conductivity can be obtained when the electrolyte is doped with larger-radius ions.As a result,the assembled thermal battery with Ga_(0.32)Ba_(0.15)-LLZO electrolyte exhibits a remarkable voltage platform of 1.81 V and a high specific capacity of 455.65 mA h g^(-1) at an elevated temperature of 525℃.The discharge specific capacity of the thermal cell at 500 mA amounts to 63%of that at 100 mA,showcasing exceptional high-current discharging performance.When assembled as prototypes with fourteen single cells connected in series,the thermal batteries deliver an activation time of 38 ms and a discharge time of 32 s with the current density of 100 mA cm^(-2).These findings suggest that Ga,Ba co-doped LLZO solid-state electrolytes with high ionic conductivities holds great potential for high-capacity,quick-initiating and high-current discharging thermal batteries.展开更多
Simple cubic black phosphorus(BP)has been recognized as a strategic material due to its exceptional structural stability under extreme conditions.In this investigation,simple cubic BP was successfully synthesized thro...Simple cubic black phosphorus(BP)has been recognized as a strategic material due to its exceptional structural stability under extreme conditions.In this investigation,simple cubic BP was successfully synthesized through shock-induced phase transformation,utilizing amorphous red phosphorus as the precursor material.The phase evolution process was systematically investigated using plane shock loading apparatus,with shock pressure and temperature parameters being precisely controlled to optimize transformation kinetics.Comprehensive phase characterization revealed the correlation between thermodynamic loading profiles and cubic BP formation efficiency.Precursor modification strategies were implemented through orthorhombic BP utilization,resulting in enhanced cubic phase yield and crystallinity.The synthesized cubic BP variants are considered promising candidates for advanced protective material systems,particularly where combinations of mechanical resilience and thermal stability are required under extreme operational conditions.This research provides critical insights into shock-induced phase transformation mechanics,while establishing foundational protocols for manufacturing non-equilibrium materials with potential applications in next-generation defensive technologies.展开更多
Initiating explosive devices(IEDs)are crucial in both military and civilian applications for improving the accuracy of controlled detonations.However,the safety of semiconductor bridge(SCB)wire IEDs,which are the most...Initiating explosive devices(IEDs)are crucial in both military and civilian applications for improving the accuracy of controlled detonations.However,the safety of semiconductor bridge(SCB)wire IEDs,which are the most widely used,is increasingly threatened by complex electromagnetic environments.Although protective devices such as thermistors and zener diodes are commonly employed to enhance safety,traditional discrete components can compromise compactness and provide only marginal improvements.The metal-insulator transition properties of vanadium dioxide(VO_(2))present an innovative approach to enhancing the safety performance of IEDs.Nevertheless,the functional relevance of the VO_(2) phase transition in relation to IEDs has garnered limited scientific attention.The VO_(2) film fabricated via 3D printing demonstrated resistivity modulation ranging from 2 to 5 orders of magnitude,achieving a stable metallic-state resistance of 1.2Ω.The results show that this process increases the 5-min safe current threshold by 90%,from 1 A to 1.9 A,and reduces the temperature generated by the current by approximately 40%when below the safe current threshold.Integrating VO_(2) film into IEDs via semiconductor processes significantly enhances safety performance while maintaining detonation capability,demonstrating its effectiveness as a safety modulator in pyrotechnic engineering.展开更多
The measurement field of view of the conventional transmission electron microscopy(TEM)nano-moiréand scanning transmission electron microscopy(STEM)nano-moirémethods is limited to the hundred-nanometer scale...The measurement field of view of the conventional transmission electron microscopy(TEM)nano-moiréand scanning transmission electron microscopy(STEM)nano-moirémethods is limited to the hundred-nanometer scale,unable to meet the deformation field measurement requirements of micrometer-scale materials such as transistors and micro-devices.This paper proposed a novel measurement method based on scanning secondary moire,which can realize cross-scale deformation field measurement from nanometers to micrometers and solve the problem of insufficient measurement accuracy when using only the TEM moire method.This method utilized the electron wave in the TEM passing through the atomic lattice of two layers of different materials to generate TEM moire.On this basis,the TEM was tuned to the STEM mode,and by adjusting parameters such as the amount of defocusing,magnification,scanning angle,etc.,the electron beam was focused on the position near the interface of the two layers of materials,and at the same time,the scanning line was made approximately parallel to the direction of one of the TEM moire fringes.The scanning secondary moire patterns were generated when the scanning spacing was close to the TEM moire spacing.Through this method,the deformation field,mechanical properties,and internal defects of crystals can be detected by a large field of view with high sensitivity and high efficiency.Compared to traditional methods,the advantages of scanning secondary moire method lie in significantly improving the measurement field of TEM moire and STEM moire methods,realizing the cross-scale visualization measurement from nanometers to micrometers,and possessing atomic-level displacement measurement sensitivity.It can also simplify and efficiently identify dislocations,offering a new method for large-area visualization observation of dislocation density in broad application prospects.展开更多
With resource exploitation and engineering construction gradually going deeper,the surrounding rock dynamic disaster becomes frequent and violent.The anchorage support is a common control method of surrounding rock in...With resource exploitation and engineering construction gradually going deeper,the surrounding rock dynamic disaster becomes frequent and violent.The anchorage support is a common control method of surrounding rock in underground engineering.To study the dynamic damage characteristics of anchored rock and the energy absorption control mechanism of dynamic disasters,a new type of constant resistance and energy absorption(CREA)material with high strength,high elongation and high energy absorption characteristics is developed.A contrast test of rockbursts in anchored rock with different support materials is conducted.The test results show that the surface damage rates and energy release degree of anchored rock with common bolt(CB)and CREA are lower than those of unanchored rock,respectively.The total energy,average energy and maximum energy released by CREA anchored rock are 30.9%,94.3%and 84.4%lower than those of CB anchored rock.Compared with unanchored rock,the rockburst peak stress in the CREA anchored rock is increased by 39.9%,and the rockburst time is delayed by 53.2%.Based on the rockburst energy calculation model,the evolution law of rockburst peak stress and energy release is investigated.The control mechanism of CREA support units on rock dynamic failure is clarified.展开更多
As a potential substitute for traditional nonaqueous organic electrolytes,polymer-based solid-state electrolytes(SSEs)have the advantages of high safety,flexibility,low density,and easy processing.In contrast,they sti...As a potential substitute for traditional nonaqueous organic electrolytes,polymer-based solid-state electrolytes(SSEs)have the advantages of high safety,flexibility,low density,and easy processing.In contrast,they still face challenges,such as low room-temperature ionic conductivity,narrow electrochemical windows,and poor mechanical strength.To realize the practical application of all-solid-state alkali metal ion batteries,there has been a lot of research on modifying the chemical composition or structure of polymerbased SSEs.In this review,the transport mechanism of alkali metal ions in polymer SSEs is briefly introduced.We systematically summarize the recent strategies to improve polymer-based SSEs,which have been validated in lithium-ion batteries and sodium-ion batteries,including lamellar electrolyte structure,dual salts hybridization,oriented filler alignment,and so on.Then,taking the unique properties of potassium metal and potassium ions into consideration,the feasibility of potassium-ion batteries for practical use enabled by these novel modification methods is discussed.展开更多
Cerium-aluminum(CeAl)alloy is promising reactive structural materials(RSMs)with significant potential for liner applications.To investigate the thermochemical characteristics of CeAl alloy and the perforation behavior...Cerium-aluminum(CeAl)alloy is promising reactive structural materials(RSMs)with significant potential for liner applications.To investigate the thermochemical characteristics of CeAl alloy and the perforation behavior of its liner impacting steel targets,a CeAl alloy liner with 5 wt%Al content was fabricated,with a cerium(Ce)liner and a copper(Cu)liner used as control.The microstructure and elemental distribution of the CeAl alloy were analyzed using SEM,EDS,and XRD.The thermochemical reaction mechanism of the CeAl alloy was examined through TG-DSC.Penetration experiments were conducted to explore the combined effects of invasion and implosion of CeAl alloy liner against steel target.The results indicate that the addition of Al leads to the formation of Ce_(3)Al intermetallic compounds in the alloy and reduces the apparent activation energy of the Ce-based alloy by around 53.17%,thereby facilitating energy release.The presence of 5 wt%Al increases the calorific value by approximately 24.5%,and this change allows the oxidation process to be divided into three distinct stages.Compared to an inert copper liner,the average penetration diameter of the CeAl_(5) reactive alloy liner increases by around 42.78%.Furthermore,when compared to the Ce liner,the penetration depth of the CeAl_(5) reactive alloy liner increases by approximately 82.64%.展开更多
Combustion catalyst is a key modifier for the performance of composite solid propellant.To exploit highefficiency combustion catalyst,a fascinating bimetallic metal-organic framework[MnCo(EIM)_(2)(DCA)_(2)]n(1)was con...Combustion catalyst is a key modifier for the performance of composite solid propellant.To exploit highefficiency combustion catalyst,a fascinating bimetallic metal-organic framework[MnCo(EIM)_(2)(DCA)_(2)]n(1)was constructed by an active dicyandiamide(DCA)linker,Mn^(2+),Co^(2+)centers,and an 1-ethylimidazole(EIM)ligand.1 possesses good thermal stability(Tp=205℃),high energy density(Eg=24.34 kJ/g,Ev=35.93 kJ/cm^(3)),and insensitivity to impact and frictional stimulus.The catalytic effects of 1 contrasted to monometallic coordination compounds Mn(EIM)_(4)(DCA)_(2)(2)and Co(EIM)_(4)(DCA)_(2)(3)on the thermal decomposition of AP/RDX composite were investigated by a DSC method.The decomposition peak temperatures of AP and RDX of the composite decreased to 335.8℃ and 206.4℃,respectively,and the corresponding activation energy decreased by 27.3%and 43.6%,respectively,which are better than the performances of monometallic complexes 2 and 3.The gas products in the whole thermal decomposition stage of the sample were measured by TG-MS and TG-IR,and the catalytic mechanism of 1 to AP/RDX was further analyzed.This work reveal potential application of bimetallic MOFs in the composite solid propellants.展开更多
The interfacial structure has an important effect on the mechanical properties and safety of the energetic material.In this work,a mesostructure model reflecting the real internal structure of PBX is established throu...The interfacial structure has an important effect on the mechanical properties and safety of the energetic material.In this work,a mesostructure model reflecting the real internal structure of PBX is established through image digital modeling and vectorization processing technology.The microscopic molecular structure model of PBX is constructed by molecular dynamics,and the interface bonding energy is calculated and transferred to the mesostructure model.Numerical simulations are used to study the influence of the interface roughness on the dynamic compression and impact ignition response of PBX,and to regulate and optimize the mechanical properties and safety of the explosive to obtain the optimal design of the surface roughness of the explosive crystal.The results show that the critical hot spot density of PBX ignition under impact loading is 0.68 mm^(-2).The improvement of crystal surface roughness can improve the mechanical properties of materials,but at the same time it can improve the impact ignition sensitivity and reduce the safety of materials.The optimal friction coefficient range for the crystal surface that satisfies both the mechanical properties and safety of PBX is 0.06-0.12.This work can provide a reference basis for the formulation design and production processing of energetic materials.展开更多
Compared with PELE with inert fillings such as polyethylene and nylon,reactive PELE(RPELE)shows excellent damage effects when impacting concrete targets due to the filling deflagration reaction.In present work,an anal...Compared with PELE with inert fillings such as polyethylene and nylon,reactive PELE(RPELE)shows excellent damage effects when impacting concrete targets due to the filling deflagration reaction.In present work,an analytical model describing the jacket deformation and concrete target damage impacted by RPELE was presented,in which the radial rarefaction and filling deflagration reaction were considered.The impact tests of RPELE on concrete target in the 592-1012 m/s were carried out to verify the analytical model.Based on the analytical model,the angle-length evolution mechanism of the jacket bending-curling deformation was revealed,and the concrete target damage was further analyzed.One can find out that the average prediction errors of the front crater,opening and back crater are 6.8%,8.5%and 7.1%,respectively.Moreover,the effects of radial rarefaction and deflagration were discussed.It was found that the neglect of radial rarefaction overestimates the jacket deformation and concrete target damage,while the deflagration reaction of filling increases the diameter of the front crater,opening and back crater by 25.4%,24.3%and 31.1%,respectively.The research provides a valuable reference for understanding and predicting the jacket deformation and concrete target damage impacted by RPELE.展开更多
Boron has been considered a promising powdered metal fuel for enhancing composite propellants'energy output due to its high energy density.However,the high ignition temperature and low combustion efficiency limit ...Boron has been considered a promising powdered metal fuel for enhancing composite propellants'energy output due to its high energy density.However,the high ignition temperature and low combustion efficiency limit the application of boron powder due to the high boiling point of the boron oxide layer.Much research is ongoing to overcome these shortcomings,and one potential approach is to introduce a small quantity of metal oxide additives to promote the reaction of boron.This study prepared boron-rich fuels with 10 wt%of eight nano-metal oxide additives by mechanical ball milling.The effect of metal oxides on the thermo-oxidation,ignition,and combustion properties of boron powder was comprehensively studied by the thermogravimetric analysis(TG),the electrically heated filament setup(T-jump),and the laser-induced combustion experiments.TG experiments at 5 K/min found that Bi_(2)O_(3),MoO_(3),TiO_(2),Fe_(2)O_(3),and CuO can promote thermo-oxidation of boron.Compared to pure boron,Tonsetcan be reduced from 569℃to a minimum of 449℃(B/Bi_(2)O_(3)).Infrared temperature measurement in T-jump tests showed that when heated by an electric heating wire at rates from 1000 K/s to 25000 K/s,the ignition temperatures of B/Bi_(2)O_(3) are the lowest,even lower than the melting point of boron oxide.Ignition images and SEM for the products further showed that the high heating rate is beneficial to the rapid reaction of boron powder in the single-particle combustion state.Fuels(B/Bi_(2)O_(3),B/MoO_(3),and B/CuO)were mixed with the oxidant AP and ignited by laser to study the combustion performance.The results showed that B/CuO/AP has the largest flame area,the highest BO_(2) characteristic spectral intensity,and the largest burn rate for powder lines.To combine the advantages of CuO and Bi_(2)O_(3),binary metal oxide(CBO,mass ratio of 3:1)was prepared and the test results showed that CBO can very well improve both ignition and combustion properties of boron.Especially B/CBO/AP has the highest burn rate compared with all fuels containing other additives.It was found that multi-component metal-oxide additive can more synergistically improve the reaction characteristics of boron powder than unary additive.These findings contribute to the development of boron-rich fuels and their application in propellants.展开更多
The penetration-deflagration coupling damage performance of rod-like reactive shaped charge pene-trator(RRSCP)impacting thick steel plates is investigated by theoretical analysis and experiments.A penetration-deflagra...The penetration-deflagration coupling damage performance of rod-like reactive shaped charge pene-trator(RRSCP)impacting thick steel plates is investigated by theoretical analysis and experiments.A penetration-deflagration coupling damage model is developed to predict the penetration depth and cratering diameter.Four type of aluminum-polytetrafluoroethylene-copper(Al-PTFE-Cu)reactive liners with densities of 2.3,2.7,3.5,and 4.5 g·cm^(-3) are selected to conduct the penetration experiments.The comparison results show that model predictions are in good agreement with the experimental data.By comparing the penetration depth and cratering diameter in the inert penetration mode and the penetration-deflagration coupling mode,the influence mechanism that the penetration-induced chemical response is unfavorable to penetration but has an enhanced cratering effect is revealed.From the formation characteristics,penetration effect and penetration-induced chemical reaction be-haviors,the influence of reactive liner density on the penetration-deflagration performance is further analyzed.The results show that increasing the density of reactive liner significantly increases both the kinetic energy and length of the reactive penetrator,meanwhile effectively reduces the weakened effect of penetration-induced chemical response,resulting in an enhanced penetration capability.However,due to the decreased diameter and potential energy content of reactive penetrator,the cratering capa-bility is weakened significantly.展开更多
Aiming at mitigating the high risks associated with conventional explosive blasting,this study developed a safe directional fracturing technique,i.e.instantaneous expansion with a single fracture(IESF),using a coal-ba...Aiming at mitigating the high risks associated with conventional explosive blasting,this study developed a safe directional fracturing technique,i.e.instantaneous expansion with a single fracture(IESF),using a coal-based solid waste expanding agent.First,the mechanism of directional fracturing blasting by the IESF was analyzed,and the criterion of directional crack initiation was established.On this basis,laboratory experiments and numerical simulations were conducted to systematically evaluate the directional fracturing blasting performance of the IESF.The results indicate that the IESF presents an excellent directional fracturing effect,with average surface undulation differences ranging from 8.1 mm to 22.7 mm on the fracture surfaces.Moreover,during concrete fracturing tests,the stresses and strains in the fracturing direction are measured to be 2.16-3.71 times and 8 times larger than those in the nonfracturing direction,respectively.Finally,the IESF technique was implemented for no-pillar mining with gob-side entry retaining through roof cutting and pressure relief in an underground coal mine.The IESF technique effectively created directional cracks in the roof without causing severe roadway deformation,achieving an average cutting rate and maximum roadway deformation of 94%and 197 mm,respectively.These on-site test results verified its excellent directional rock fracturing performance.The IESF technique,which is safe,efficient,and green,has considerable application prospects in the field of rock mechanics and engineering.展开更多
Thermal batteries are a type of thermally activated reserve battery,where the cathode material significantly influences the operating voltage and specific capacity.In this work,Cu_(2)O–CuO nanowires are prepared by i...Thermal batteries are a type of thermally activated reserve battery,where the cathode material significantly influences the operating voltage and specific capacity.In this work,Cu_(2)O–CuO nanowires are prepared by in-situ thermal oxidation method onto Cu foam,which are further coated with a carbon layer derived from polydopamine(PDA).The morphology of the nanowires has been examined using scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The material shows a kind of core–shell structure,with CuO as the shell and Cu_(2)O as the core.To further explore the interaction between the material and lithium-ion(Li^(+)),the Lit adsorption energies of CuO and Cu_(2)O were calculated,revealing a stronger affinity of Li^(+) for CuO.The unique core–shell nanowire structure of Cu_(2)O–CuO can provide a good Li^(+)adsorption with the outer layer CuO and excellent structural stability with the inner layer Cu_(2)O.When applied in thermal batteries,Cu_(2)O–CuO–C nanowires exhibit specific capacity and specific energy of 326 mAh g^(-1)and 697 Wh kg^(-1)at a cut-off voltage of 1.5 V both of which are higher than those of Cu_(2)O–CuO(238 mAh g^(-1)and 445 Wh kg^(-1)).The discharge process includes the insertion of lithium ions and subsequent reduction reactions,ultimately resulting in the formation of lithium oxide and copper.展开更多
This study calculates the combustion characteristics of various gas-generating and micro gas pyrotechnic charges,including aluminium/potassium perchlorate,boron/potassium nitrate,carbon black/potassium nitrate,and sil...This study calculates the combustion characteristics of various gas-generating and micro gas pyrotechnic charges,including aluminium/potassium perchlorate,boron/potassium nitrate,carbon black/potassium nitrate,and silicon-based delay compositions,using thermodynamic software.A multiphase flowthermal-solid coupling model was established,and the combustion process of the pyrotechnic charges within a closed bomb was simulated.The pyrotechnic shock generated by combustion was predicted.The combustion pressures and pyrotechnic shocks were measured.The simulation results demonstrated good agreement with experimental results.Additionally,the mechanism of shock generation by the combustion of pyrotechnic charges in the closed bomb was analyzed.The effects of the combustion characteristics of the pyrotechnic charges on the resulting pyrotechnic shocks were systematically investigated.Notably,the shock response spectrum of the gas-generating pyrotechnic charges is greater than that of the micro gas compositions at most frequencies,particularly in the mid-field pyrotechnic shocks(3-10 kHz).Furthermore,the pyrotechnic shocks increase approximately linearly with the impulse of the gas-generating pyrotechnic charges.展开更多
基金National Natural Science Foundation of China(12002045)Supported by State Key Laboratory of Explosion Science and Safety Protection,Beijing Institute of Technology(QNKT22-09)。
文摘A high-density tungsten-zirconium-titanium(W-Zr-Ti)reactive alloy was prepared by powder metallurgy.This alloy exhibits high density,high strength,and violent energy release characteristics,resulting in outstanding penetration and ignition abilities.Dynamic impact experiment demonstrated its strain rate hardening effect,and the energetic characteristics were investigated by digital image processing technique and thermal analysis experiment.The results show that W-Zr-Ti reactive alloy performs compressive strength of 2.25 GPa at 5784 s^(-1)strain rate,and its exothermic reaction occurs at about 961 K.Based on the explosion test and shock wave theory,thresholds of enhanced damage effect are less than 35.77 GPa and 5.18×10^(4)kJ/m^(2)for shock pressure and energy,respectively.Furthermore,the transformation of fracture behavior and failure mechanism is revealed,which causes the increase in compressive strength and reaction intensity under dynamic loading.
基金supported by the National Natural Science Foundation of China(Grant No.12372351).
文摘In this study, to meet the development and application requirements for high-strength and hightoughness energetic structural materials, a representative volume element of a TA15 matrix embedded with a TaZrNb sphere was designed and fabricated via diffusion bonding. The mechanisms of the microstructural evolution of the TaZrNb/TA15 interface were investigated via SEM, EBSD, EDS, and XRD.Interface mechanical property tests and in-situ tensile tests were conducted on the sphere-containing structure, and an equivalent tensile-strength model was established for the structure. The results revealed that the TA15 titanium alloy and joint had high density and no pores or cracks. The thickness of the planar joint was approximately 50-60 μm. The average tensile and shear strengths were 767 MPa and 608 MPa, respectively. The thickness of the spherical joint was approximately 60 μm. The Zr and Nb elements in the joint diffused uniformly and formed strong bonds with Ti without forming intermetallic compounds. The interface exhibited submicron grain refinement and a concave-convex interlocking structure. The tensile fracture surface primarily exhibited intergranular fracture combined with some transgranular fracture, which constituted a quasi-brittle fracture mode. The shear fracture surface exhibited brittle fracture with regular arrangements of furrows. Internal fracture occurred along the spherical interface, as revealed by advanced in-situ X-ray microcomputed tomography. The experimental results agreed well with the theoretical predictions, indicating that the high-strength interface contributes to the overall strength and toughness of the sphere-containing structure.
基金supported by the National Natural Science Foundation of China(No.12172051,12172050,12141201,and 12221002)。
文摘Predictions of extreme near-field blast wave for cylindrical charge is crucial for designing sympathetic detonation protection structures,yet the quantitative analysis of detonation products and shock wave field are still insufficient.The present work conducted experiments and numerical simulations of nearfield explosion for kilogram scale cylindrical charge,and investigated the propagation and spatial distribution characteristics of incident and reflected blast waves.The results show that near-field reflected overpressure exhibits multi-peak structures,which are primarily governed by reflections of detonation products and shock wave.The reflected peak overpressure dominated by detonation products shows higher sensitivity to scaled distance.Meanwhile,the Rayleigh-Taylor instability(RTI)effect induces the evolutions of detonation products and shock wave interface from smooth to random microjets,increasing dispersion of secondary re flected peak overpressure.In free-field explosion,the incident peak overpressure exhibits a dual-peak structure,governed by the shock wave front and detonation products flowing past the gauge points.The incident peak overpressure dominated by detonation products is sensitive to orientations due to the charge structures.As the aspect ratio of charge increases from 0.6 to 8,the dominant radial azimuth angle region expands from 60°-90°to 30°-90°.An empirical model was developed to predict the spatial distributions of incident peak loads at arbitrary orientations for cylindrical charge with 0.6≤L/D≤8.0 and 0.06 m·kg^(-1/3)
基金Project(2023YFC2907600)supported by the National Key Research and Development Program of ChinaProjects(42277174,42477166)supported by the National Natural Science Foundation of China+1 种基金Project(2024JCCXSB01)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(KFJJ24-01M)supported by the State Key Laboratory of Explosion Science and Safety Protection,Beijing Institute of Technology,China。
文摘Considering the characteristics of deep thick top coal roadway,in which the high ground stress,coal seam with low strength,and a large range of surrounding rock fragmentation,the pressure relief anchor box beam support system with high strength is developed.The high-strength bearing characteristics and coupling yielding support mechanism of this support system are studied by the mechanical tests of composite members and the combined support system.The test results show that under the coupling effect of support members,the peak stress of the box-shaped support beam in the anchor box beam is reduced by 21.9%,and the average deformation is increased by 135.0%.The ultimate bending bearing capacity of the box-shaped support beam is 3.5 times that of traditional channel beam.The effective compressive stress zone applied by the high prestressed cable is expanded by 26.4%.On this basis,the field support comparison test by the anchor channel beam,the anchor I-shaped beam and the anchor box beam are carried out.Compared with those of the previous two,the surrounding rock convergence of the latter is decreased by 41.2%and 22.2%,respectively.The field test verifies the effectiveness of the anchor box beam support system.
基金supported by the National Natural Science Foundation of China(NSFC,Grant Nos.11872120,12102050)Key Laboratory of Explosion Science and Technology(Grant No.QNKT22-01).
文摘The new CL-20(hexanitrohexaazaisowurtzitane)type aluminized explosives in the overdrive detonation(ODD)conditions of the core problem is how to accurately represent the state of the overdrive detonation products.To this end,this paper is based on the impedance matching method to test the ODD conditions of CL-20 type aluminium explosive particle velocity.Calculated the interfacial pressure of the shock wave in different media.Determined the characteristic parameters of the reaction zone of the detonation of CL-20 aluminized explosives.Calibrated the parameters of the JoneseWilkinseLee(JWL)+γ equation for the detonation products(DPs).Revealed the effect of different DPs equation of state(EOS)on the Hugoniot pressure of ODD.The results indicate that when the content of aluminum powder ranges from 0%to 30%,the duration of the ODD reaction zone and the width of the detonation reaction zone of the CL-20-based aluminized explosive are directly proportional to the content of aluminum powder.The width of the detonation reaction zone is increased by 1.97 times to 2.7 times compared to that of the reaction zone without the addition of aluminum powder.However,the energy release efficiency of the detonation reaction zone is inversely proportional to the content of aluminum powder.When the aluminum powder content was held constant,the incorporation of AP caused a 25%reduction in the energy release efficiency of the detonation reaction zone.Compared with existing ODD state equations,the JWL +γ equation is superior in calibrating overpressure Hugoniot data and the isentropic expansion in the C-J state.The deviation between calculated pressure results and experimental measurements is within 6%.
基金the National Key R&D Program of China(No.2023YFC3009501)the National Natural Science Foundation of China(No.52374298)+1 种基金the project of State Key Laboratory of Explosion Science and Safety Protection(Beijing Institute of Technology,No.QNKT23-17)Aeronautical Science Foundation of China(No.20174072003).
文摘Garnet Li_(7)La_(3)Zr_(2)O_(12)(LLZO)electrolytes have been recognized as a promising candidate to replace liquid/molten-state electrolytes in battery applications due to their exceptional performance,particularly Ga-doped LLZO(LLZGO),which exhibits high ionic conductivity.However,the limited size of the Liþtransport bottleneck restricts its high-current discharging performance.The present study focuses on the synthesis of Ga^(3+)þand Ba^(2+)þco-doped LLZO(LLZGBO)and investigates the influence of doping contents on the morphology,crystal structure,Liþtransport bottleneck size,and ionic conductivity.In particular,Ga_(0.32)Ba_(0.15)exhibits the highest ionic conductivity(6.11E-2 S cm^(-1) at 550 C)in comparison with other compositions,which can be attributed to its higher-energy morphology,larger bottleneck and unique Liþtransport channel.In addition to Ba^(2+),Sr^(2+)þand Ca^(2+)have been co-doped with Ga3þinto LLZO,respectively,to study the effect of doping ion radius on crystal structures and the properties of electrolytes.The characterization results demonstrate that the easier Liþtransport and higher ionic conductivity can be obtained when the electrolyte is doped with larger-radius ions.As a result,the assembled thermal battery with Ga_(0.32)Ba_(0.15)-LLZO electrolyte exhibits a remarkable voltage platform of 1.81 V and a high specific capacity of 455.65 mA h g^(-1) at an elevated temperature of 525℃.The discharge specific capacity of the thermal cell at 500 mA amounts to 63%of that at 100 mA,showcasing exceptional high-current discharging performance.When assembled as prototypes with fourteen single cells connected in series,the thermal batteries deliver an activation time of 38 ms and a discharge time of 32 s with the current density of 100 mA cm^(-2).These findings suggest that Ga,Ba co-doped LLZO solid-state electrolytes with high ionic conductivities holds great potential for high-capacity,quick-initiating and high-current discharging thermal batteries.
基金supported by the Youth Project of the Independent Subject of the State Key Laboratory of Explosion Science and Safety Protection,Beijing Institute of Technology(Grant Nos.QNKT25-13 and QNKT24-02)the 76th batch of Project funded by China Postdoctoral Science Foundation(Grant No.2024M764116)+3 种基金the National Natural Science Foundation of China(Grant Nos.12002048,12072037,12102050,and 12202067)the Science and Technology Commission,China(Grant No.2019-jcjc-zd-011-00)the Project supported by the Open Funds of Kui Yuan Laboratory(Grant No.KY202431)the State Key Laboratory of Explosion Science and Safety Protection(Grant No.KFJJ25-21M)。
文摘Simple cubic black phosphorus(BP)has been recognized as a strategic material due to its exceptional structural stability under extreme conditions.In this investigation,simple cubic BP was successfully synthesized through shock-induced phase transformation,utilizing amorphous red phosphorus as the precursor material.The phase evolution process was systematically investigated using plane shock loading apparatus,with shock pressure and temperature parameters being precisely controlled to optimize transformation kinetics.Comprehensive phase characterization revealed the correlation between thermodynamic loading profiles and cubic BP formation efficiency.Precursor modification strategies were implemented through orthorhombic BP utilization,resulting in enhanced cubic phase yield and crystallinity.The synthesized cubic BP variants are considered promising candidates for advanced protective material systems,particularly where combinations of mechanical resilience and thermal stability are required under extreme operational conditions.This research provides critical insights into shock-induced phase transformation mechanics,while establishing foundational protocols for manufacturing non-equilibrium materials with potential applications in next-generation defensive technologies.
文摘Initiating explosive devices(IEDs)are crucial in both military and civilian applications for improving the accuracy of controlled detonations.However,the safety of semiconductor bridge(SCB)wire IEDs,which are the most widely used,is increasingly threatened by complex electromagnetic environments.Although protective devices such as thermistors and zener diodes are commonly employed to enhance safety,traditional discrete components can compromise compactness and provide only marginal improvements.The metal-insulator transition properties of vanadium dioxide(VO_(2))present an innovative approach to enhancing the safety performance of IEDs.Nevertheless,the functional relevance of the VO_(2) phase transition in relation to IEDs has garnered limited scientific attention.The VO_(2) film fabricated via 3D printing demonstrated resistivity modulation ranging from 2 to 5 orders of magnitude,achieving a stable metallic-state resistance of 1.2Ω.The results show that this process increases the 5-min safe current threshold by 90%,from 1 A to 1.9 A,and reduces the temperature generated by the current by approximately 40%when below the safe current threshold.Integrating VO_(2) film into IEDs via semiconductor processes significantly enhances safety performance while maintaining detonation capability,demonstrating its effectiveness as a safety modulator in pyrotechnic engineering.
基金supported by the National Natural Science Foundation of China(Grant Nos.12372178 and 12327801).
文摘The measurement field of view of the conventional transmission electron microscopy(TEM)nano-moiréand scanning transmission electron microscopy(STEM)nano-moirémethods is limited to the hundred-nanometer scale,unable to meet the deformation field measurement requirements of micrometer-scale materials such as transistors and micro-devices.This paper proposed a novel measurement method based on scanning secondary moire,which can realize cross-scale deformation field measurement from nanometers to micrometers and solve the problem of insufficient measurement accuracy when using only the TEM moire method.This method utilized the electron wave in the TEM passing through the atomic lattice of two layers of different materials to generate TEM moire.On this basis,the TEM was tuned to the STEM mode,and by adjusting parameters such as the amount of defocusing,magnification,scanning angle,etc.,the electron beam was focused on the position near the interface of the two layers of materials,and at the same time,the scanning line was made approximately parallel to the direction of one of the TEM moire fringes.The scanning secondary moire patterns were generated when the scanning spacing was close to the TEM moire spacing.Through this method,the deformation field,mechanical properties,and internal defects of crystals can be detected by a large field of view with high sensitivity and high efficiency.Compared to traditional methods,the advantages of scanning secondary moire method lie in significantly improving the measurement field of TEM moire and STEM moire methods,realizing the cross-scale visualization measurement from nanometers to micrometers,and possessing atomic-level displacement measurement sensitivity.It can also simplify and efficiently identify dislocations,offering a new method for large-area visualization observation of dislocation density in broad application prospects.
基金supported by the National Key Research and Development Program of China(No.2023YFC2907600)the National Natural Science Foundation of China(Nos.42477166 and 42277174)+2 种基金the Fundamental Research Funds for the Central Universities,China(No.2024JCCXSB01)the Opening Project of State Key Laboratory of Explosion Science and Safety Protection,Beijing Institute of Technology(No.KFJJ24-01M)the Open Foundation of Collaborative Innovation Center of Green Development and Ecological Restoration of Mineral Resources(No.HLCX2024-04)。
文摘With resource exploitation and engineering construction gradually going deeper,the surrounding rock dynamic disaster becomes frequent and violent.The anchorage support is a common control method of surrounding rock in underground engineering.To study the dynamic damage characteristics of anchored rock and the energy absorption control mechanism of dynamic disasters,a new type of constant resistance and energy absorption(CREA)material with high strength,high elongation and high energy absorption characteristics is developed.A contrast test of rockbursts in anchored rock with different support materials is conducted.The test results show that the surface damage rates and energy release degree of anchored rock with common bolt(CB)and CREA are lower than those of unanchored rock,respectively.The total energy,average energy and maximum energy released by CREA anchored rock are 30.9%,94.3%and 84.4%lower than those of CB anchored rock.Compared with unanchored rock,the rockburst peak stress in the CREA anchored rock is increased by 39.9%,and the rockburst time is delayed by 53.2%.Based on the rockburst energy calculation model,the evolution law of rockburst peak stress and energy release is investigated.The control mechanism of CREA support units on rock dynamic failure is clarified.
基金Fundamental Research Funds for the Central Universities,Grant/Award Number:FRF-IDRY-21-013National Natural Science Foundation of China,Grant/Award Numbers:52371131,52474318+1 种基金Beijing Nova Program,Grant/Award Number:Z211100002121082State Key Laboratory of Explosion Science and Technology,Grant/Award Number:QNKT23-05。
文摘As a potential substitute for traditional nonaqueous organic electrolytes,polymer-based solid-state electrolytes(SSEs)have the advantages of high safety,flexibility,low density,and easy processing.In contrast,they still face challenges,such as low room-temperature ionic conductivity,narrow electrochemical windows,and poor mechanical strength.To realize the practical application of all-solid-state alkali metal ion batteries,there has been a lot of research on modifying the chemical composition or structure of polymerbased SSEs.In this review,the transport mechanism of alkali metal ions in polymer SSEs is briefly introduced.We systematically summarize the recent strategies to improve polymer-based SSEs,which have been validated in lithium-ion batteries and sodium-ion batteries,including lamellar electrolyte structure,dual salts hybridization,oriented filler alignment,and so on.Then,taking the unique properties of potassium metal and potassium ions into consideration,the feasibility of potassium-ion batteries for practical use enabled by these novel modification methods is discussed.
文摘Cerium-aluminum(CeAl)alloy is promising reactive structural materials(RSMs)with significant potential for liner applications.To investigate the thermochemical characteristics of CeAl alloy and the perforation behavior of its liner impacting steel targets,a CeAl alloy liner with 5 wt%Al content was fabricated,with a cerium(Ce)liner and a copper(Cu)liner used as control.The microstructure and elemental distribution of the CeAl alloy were analyzed using SEM,EDS,and XRD.The thermochemical reaction mechanism of the CeAl alloy was examined through TG-DSC.Penetration experiments were conducted to explore the combined effects of invasion and implosion of CeAl alloy liner against steel target.The results indicate that the addition of Al leads to the formation of Ce_(3)Al intermetallic compounds in the alloy and reduces the apparent activation energy of the Ce-based alloy by around 53.17%,thereby facilitating energy release.The presence of 5 wt%Al increases the calorific value by approximately 24.5%,and this change allows the oxidation process to be divided into three distinct stages.Compared to an inert copper liner,the average penetration diameter of the CeAl_(5) reactive alloy liner increases by around 42.78%.Furthermore,when compared to the Ce liner,the penetration depth of the CeAl_(5) reactive alloy liner increases by approximately 82.64%.
基金supported by the National Natural Science Foundation of China(Grant No.22175025)State Key Laboratory of Explosion Science and Safety Protection(Grant No.YBKT22-03)+1 种基金the Natural Science Foundation of Chongqing(Grant No.CSTB2023 NSCQ-LZX0098)the Chongqing Municipal Education Commis-sion(Grant No.KJZD-M202301404).
文摘Combustion catalyst is a key modifier for the performance of composite solid propellant.To exploit highefficiency combustion catalyst,a fascinating bimetallic metal-organic framework[MnCo(EIM)_(2)(DCA)_(2)]n(1)was constructed by an active dicyandiamide(DCA)linker,Mn^(2+),Co^(2+)centers,and an 1-ethylimidazole(EIM)ligand.1 possesses good thermal stability(Tp=205℃),high energy density(Eg=24.34 kJ/g,Ev=35.93 kJ/cm^(3)),and insensitivity to impact and frictional stimulus.The catalytic effects of 1 contrasted to monometallic coordination compounds Mn(EIM)_(4)(DCA)_(2)(2)and Co(EIM)_(4)(DCA)_(2)(3)on the thermal decomposition of AP/RDX composite were investigated by a DSC method.The decomposition peak temperatures of AP and RDX of the composite decreased to 335.8℃ and 206.4℃,respectively,and the corresponding activation energy decreased by 27.3%and 43.6%,respectively,which are better than the performances of monometallic complexes 2 and 3.The gas products in the whole thermal decomposition stage of the sample were measured by TG-MS and TG-IR,and the catalytic mechanism of 1 to AP/RDX was further analyzed.This work reveal potential application of bimetallic MOFs in the composite solid propellants.
基金National Natural Science Foundation of China(Grant No.U22B20131)General Program of National Nature Science Foundation of China(Grant No.12202060)for supporting this project。
文摘The interfacial structure has an important effect on the mechanical properties and safety of the energetic material.In this work,a mesostructure model reflecting the real internal structure of PBX is established through image digital modeling and vectorization processing technology.The microscopic molecular structure model of PBX is constructed by molecular dynamics,and the interface bonding energy is calculated and transferred to the mesostructure model.Numerical simulations are used to study the influence of the interface roughness on the dynamic compression and impact ignition response of PBX,and to regulate and optimize the mechanical properties and safety of the explosive to obtain the optimal design of the surface roughness of the explosive crystal.The results show that the critical hot spot density of PBX ignition under impact loading is 0.68 mm^(-2).The improvement of crystal surface roughness can improve the mechanical properties of materials,but at the same time it can improve the impact ignition sensitivity and reduce the safety of materials.The optimal friction coefficient range for the crystal surface that satisfies both the mechanical properties and safety of PBX is 0.06-0.12.This work can provide a reference basis for the formulation design and production processing of energetic materials.
基金funding from the National Natural Science Foundation of China(Grant Nos.12132003 and 12302460)。
文摘Compared with PELE with inert fillings such as polyethylene and nylon,reactive PELE(RPELE)shows excellent damage effects when impacting concrete targets due to the filling deflagration reaction.In present work,an analytical model describing the jacket deformation and concrete target damage impacted by RPELE was presented,in which the radial rarefaction and filling deflagration reaction were considered.The impact tests of RPELE on concrete target in the 592-1012 m/s were carried out to verify the analytical model.Based on the analytical model,the angle-length evolution mechanism of the jacket bending-curling deformation was revealed,and the concrete target damage was further analyzed.One can find out that the average prediction errors of the front crater,opening and back crater are 6.8%,8.5%and 7.1%,respectively.Moreover,the effects of radial rarefaction and deflagration were discussed.It was found that the neglect of radial rarefaction overestimates the jacket deformation and concrete target damage,while the deflagration reaction of filling increases the diameter of the front crater,opening and back crater by 25.4%,24.3%and 31.1%,respectively.The research provides a valuable reference for understanding and predicting the jacket deformation and concrete target damage impacted by RPELE.
基金State Key Laboratory of Explosion Science and Safety Protection of China (Grant No.QNKT21-8)National Natural Science Foundation of China (Grant No.12302432)to provide financial support。
文摘Boron has been considered a promising powdered metal fuel for enhancing composite propellants'energy output due to its high energy density.However,the high ignition temperature and low combustion efficiency limit the application of boron powder due to the high boiling point of the boron oxide layer.Much research is ongoing to overcome these shortcomings,and one potential approach is to introduce a small quantity of metal oxide additives to promote the reaction of boron.This study prepared boron-rich fuels with 10 wt%of eight nano-metal oxide additives by mechanical ball milling.The effect of metal oxides on the thermo-oxidation,ignition,and combustion properties of boron powder was comprehensively studied by the thermogravimetric analysis(TG),the electrically heated filament setup(T-jump),and the laser-induced combustion experiments.TG experiments at 5 K/min found that Bi_(2)O_(3),MoO_(3),TiO_(2),Fe_(2)O_(3),and CuO can promote thermo-oxidation of boron.Compared to pure boron,Tonsetcan be reduced from 569℃to a minimum of 449℃(B/Bi_(2)O_(3)).Infrared temperature measurement in T-jump tests showed that when heated by an electric heating wire at rates from 1000 K/s to 25000 K/s,the ignition temperatures of B/Bi_(2)O_(3) are the lowest,even lower than the melting point of boron oxide.Ignition images and SEM for the products further showed that the high heating rate is beneficial to the rapid reaction of boron powder in the single-particle combustion state.Fuels(B/Bi_(2)O_(3),B/MoO_(3),and B/CuO)were mixed with the oxidant AP and ignited by laser to study the combustion performance.The results showed that B/CuO/AP has the largest flame area,the highest BO_(2) characteristic spectral intensity,and the largest burn rate for powder lines.To combine the advantages of CuO and Bi_(2)O_(3),binary metal oxide(CBO,mass ratio of 3:1)was prepared and the test results showed that CBO can very well improve both ignition and combustion properties of boron.Especially B/CBO/AP has the highest burn rate compared with all fuels containing other additives.It was found that multi-component metal-oxide additive can more synergistically improve the reaction characteristics of boron powder than unary additive.These findings contribute to the development of boron-rich fuels and their application in propellants.
基金supported by the National Natural Science Foundation of China(Grant No.12172052)the Foundation of State Key Laboratory of Explosion Science and Safety Protection(Grant No.QKKT24-02).
文摘The penetration-deflagration coupling damage performance of rod-like reactive shaped charge pene-trator(RRSCP)impacting thick steel plates is investigated by theoretical analysis and experiments.A penetration-deflagration coupling damage model is developed to predict the penetration depth and cratering diameter.Four type of aluminum-polytetrafluoroethylene-copper(Al-PTFE-Cu)reactive liners with densities of 2.3,2.7,3.5,and 4.5 g·cm^(-3) are selected to conduct the penetration experiments.The comparison results show that model predictions are in good agreement with the experimental data.By comparing the penetration depth and cratering diameter in the inert penetration mode and the penetration-deflagration coupling mode,the influence mechanism that the penetration-induced chemical response is unfavorable to penetration but has an enhanced cratering effect is revealed.From the formation characteristics,penetration effect and penetration-induced chemical reaction be-haviors,the influence of reactive liner density on the penetration-deflagration performance is further analyzed.The results show that increasing the density of reactive liner significantly increases both the kinetic energy and length of the reactive penetrator,meanwhile effectively reduces the weakened effect of penetration-induced chemical response,resulting in an enhanced penetration capability.However,due to the decreased diameter and potential energy content of reactive penetrator,the cratering capa-bility is weakened significantly.
基金supported by the National Natural Science Foundation of China(Grant No.52404155)State Key Laboratory of Mining Disaster Prevention and Control(Shandong University of Science and Technology)+1 种基金Ministry of Education(Grant No.JMDPC202402)supported by the opening project of State Key Laboratory of Explosion Science and Safety Protection(Beijing Institute of Technology).The opening project number is KFJJ24-20M.
文摘Aiming at mitigating the high risks associated with conventional explosive blasting,this study developed a safe directional fracturing technique,i.e.instantaneous expansion with a single fracture(IESF),using a coal-based solid waste expanding agent.First,the mechanism of directional fracturing blasting by the IESF was analyzed,and the criterion of directional crack initiation was established.On this basis,laboratory experiments and numerical simulations were conducted to systematically evaluate the directional fracturing blasting performance of the IESF.The results indicate that the IESF presents an excellent directional fracturing effect,with average surface undulation differences ranging from 8.1 mm to 22.7 mm on the fracture surfaces.Moreover,during concrete fracturing tests,the stresses and strains in the fracturing direction are measured to be 2.16-3.71 times and 8 times larger than those in the nonfracturing direction,respectively.Finally,the IESF technique was implemented for no-pillar mining with gob-side entry retaining through roof cutting and pressure relief in an underground coal mine.The IESF technique effectively created directional cracks in the roof without causing severe roadway deformation,achieving an average cutting rate and maximum roadway deformation of 94%and 197 mm,respectively.These on-site test results verified its excellent directional rock fracturing performance.The IESF technique,which is safe,efficient,and green,has considerable application prospects in the field of rock mechanics and engineering.
基金supported by National Natural Science Foundation of China(Nos.52374298)National Natural Science Foundation of Chongqing(Nos.CSTB2023NSCQ-MSX0662)Beijing Natural Science Foundation(Nos.L243019).
文摘Thermal batteries are a type of thermally activated reserve battery,where the cathode material significantly influences the operating voltage and specific capacity.In this work,Cu_(2)O–CuO nanowires are prepared by in-situ thermal oxidation method onto Cu foam,which are further coated with a carbon layer derived from polydopamine(PDA).The morphology of the nanowires has been examined using scanning electron microscopy(SEM)and transmission electron microscopy(TEM).The material shows a kind of core–shell structure,with CuO as the shell and Cu_(2)O as the core.To further explore the interaction between the material and lithium-ion(Li^(+)),the Lit adsorption energies of CuO and Cu_(2)O were calculated,revealing a stronger affinity of Li^(+) for CuO.The unique core–shell nanowire structure of Cu_(2)O–CuO can provide a good Li^(+)adsorption with the outer layer CuO and excellent structural stability with the inner layer Cu_(2)O.When applied in thermal batteries,Cu_(2)O–CuO–C nanowires exhibit specific capacity and specific energy of 326 mAh g^(-1)and 697 Wh kg^(-1)at a cut-off voltage of 1.5 V both of which are higher than those of Cu_(2)O–CuO(238 mAh g^(-1)and 445 Wh kg^(-1)).The discharge process includes the insertion of lithium ions and subsequent reduction reactions,ultimately resulting in the formation of lithium oxide and copper.
文摘This study calculates the combustion characteristics of various gas-generating and micro gas pyrotechnic charges,including aluminium/potassium perchlorate,boron/potassium nitrate,carbon black/potassium nitrate,and silicon-based delay compositions,using thermodynamic software.A multiphase flowthermal-solid coupling model was established,and the combustion process of the pyrotechnic charges within a closed bomb was simulated.The pyrotechnic shock generated by combustion was predicted.The combustion pressures and pyrotechnic shocks were measured.The simulation results demonstrated good agreement with experimental results.Additionally,the mechanism of shock generation by the combustion of pyrotechnic charges in the closed bomb was analyzed.The effects of the combustion characteristics of the pyrotechnic charges on the resulting pyrotechnic shocks were systematically investigated.Notably,the shock response spectrum of the gas-generating pyrotechnic charges is greater than that of the micro gas compositions at most frequencies,particularly in the mid-field pyrotechnic shocks(3-10 kHz).Furthermore,the pyrotechnic shocks increase approximately linearly with the impulse of the gas-generating pyrotechnic charges.
