Preparation, Characterization and Thermal Decomposition Properties of ANPyO@PDA Composites
ZHANG Gongzhen, HE Zhiwei, RAN Xianwen, CHENG Wei, WANG Yangwen, LI Zhiyuan, ZHANG He
2023, 37(6): 063402.
Acoustic and Elastic Properties of Polycrystalline Potassium Sodium Niobate under High Pressures
XIAO Likang, FENG Qiu, FANG Leiming, ZHOU Zhangyang, XIONG Zhengwei, LAN Jianghe, YANG Jia, LIU Yi, GAO Zhipeng
2023, 37(6): 061101.
Quantum Magnetic Measurement under High Pressure Based on Color Centres in Silicon Carbide
LIU Lin, WANG Junfeng, LIU Xiaodi
2023, 37(6): 060102.
Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes /issues, but are citable by Digital Object Identifier (DOI).
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2024, 38(3)  
2024, 38(3): 1-2.  
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Topics on Multiscale Structure and Physical Properties of Materials under Dynamic Loading
High-Pressure Phase Transitions Kinetics and Physical Properties on Second-to-Microsecond Time Scales: Review, Progress and Prospects
WANG Hao, ZHAO Tingting, LI Mei, LI Junlong, PENG Shang, LIU Xuqiang, ZHAO Bohao, CHEN Yanlong, LIN Chuanlong
2024, 38(3): 030101.   doi: 10.11858/gywlxb.20240770

In recent years, the development of rapid loading techniques (such as dynamic diamond anvil cell, dDAC) and time-resolved detection technologies based on diamond anvil presses has opened up new research directions in high-pressure science. This involves exploring the evolution of material structures and physical properties under pressure (or over time) in high-pressure non-equilibrium physical processes that lie between static high-pressure and shock-wave experiments in terms of time scale and loading rate. By reviewing and summarizing the rapid loading and time-resolved probe techniques that have emerged in recent years, this paper attempts to think about and generalize high-pressure science issues and technical challenges on the microsecond to second time scale. It starts from aspects such as structure phase transition dynamics that depend on loading rate, phase transition pathways, the formation of metastable phases, microstructures, and mechanoluminescence, aiming to provide some inspiration and reference for researchers in this field.

Strain Rate-Dependent Phase Transition Behavior in Silicon
CHEN Xiaohui, LIU Lei, ZHANG Yi, LI Shourui, JING Qiumin, GAO Junjie, LI Jun
2024, 38(3): 030102.   doi: 10.11858/gywlxb.20240742

High pressure phase transition is one of the core concerns in the field of condensed matter physics, Earth and planetary science and material science. And the loading strain rate is an important influencing factor for the kinetics of phase transition. Due to the lack of in situ diagnostics of crystal structure under dynamic loading, and the limited experimental research on the phase transition behavior over a wide range of strain rates, there is no unified physical model to describe how the phase transition dynamics evolve from static compression to high strain rate shock compression. Since the high-pressure phase diagram of silicon is extremely rich and possesses a large number of substable phases, and at the same time, the kinetic factors play a crucial role in the high-pressure phase transition process of silicon, silicon is an ideal material for studying the high-pressure phase transition kinetics, which is of great significance for the theoretical modeling of universal phase-transition kinetic processes. Here, we take silicon as an example and present its phase transition behavior under quasi-static, medium strain rate and high strain rate loading in turn, highlighting the effect of loading strain rate on its high-pressure phase transition behavior.

Physico-Mechanical Behavior and Size Effect of Nano-Tungsten under High Pressure
ZHAO Kanglin, WANG Qiming, ZHANG Youjun, JIANG Gang, PENG Fang, LI Yanchun
2024, 38(3): 030103.   doi: 10.11858/gywlxb.20230756

Exploring the influence of size effect on the physical properties of materials under high pressure is helpful for the development of new materials with novel or improved properties. The static compression behaviors of polycrystalline tungsten powder with average grain sizes of 30 and 65 nm under high pressure were studied by using diamond anvil cell (DAC) combined with synchrotron radiation X-ray diffraction respectively. By analyzing the peak position and the half-height width of the X-ray diffraction spectrum at each pressure, the unit cell volume, grain size, and microscopic strain of nano-tungsten metal under high pressure were obtained. By fitting the third Birch-Murnaghan equation, the bulk moduli of 30 and 65 nm tungsten are obtained to be 257(7) GPa and 343(8) GPa, respectively. Combined with the results of previous studies, it is found that when the gain size decreases from micron to 10 nm, the yield strength of tungsten at 10 nm increases by 3.5 times compared with that of microcrystal samples; the bulk modulus shows a tendency of increasing firstly and then decreasing, and the bulk elastic modulus of tungsten at 30 nm decreases by 25% compared with that of tungsten at 65 nm.

Tensile Behavior and Mechanical Performance Analysis of High-Strength Steels at Varying Strain Rates
LUORONG Dengzhu, LIU Xiaoru, YANG Jia, XIAO Likang, GUO Liang, WEI Zhantao, ZHOU Zhangyang, YI Zao, LIU Yi, FANG Leiming, XIONG Zhengwei
2024, 38(3): 030104.   doi: 10.11858/gywlxb.20240702

High-strength steels are widely employed due to their excellent combination of high strength, good ductility, and corrosion resistance. However, they often exhibit significant strain rate sensitivity. In this study, two types of high-strength steels, Ultrafort 401 and Ferrium S53 steels, were investigated. Tensile tests were conducted at varying strain rates (10−4−103 s−1), to obtain the yield strength, the tensile strength, the uniform elongation, the hardening index and other performance parameters. The variations of these parameters with strain rate were thoroughly analyzed. It was observed that under different strain rates, Ferrium S53 steel consistently outperformed Ultrafort 401 steel in terms of tensile properties, while they exhibited different trends. As the strain rate increased, both of the yield strength and the tensile strength of Ultrafort 401 steels increased, while for Ferrium S53 steels the yield strength of increased, and the tensile strength decreased and then increased. Combined with the microstructure analysis, it is found that the higher yield strength of Ferrium S53 steel was related to the smaller grain sizes, while the different tensile strength trends of the two high-strength steels with the increase of strain rate were associated with differences in strain hardening response. With the increase of strain rate, the dimple size of Ultrafort 401 steels increases, whereas it decreases and then increases for Ferrium S53 steels. This indicates a different pattern of change in the strain hardening level of the two high-strength steels with increasing strain rate. The findings in this work provide a scientific basis for assessing the mechanical performance of high-strength steels under various loading conditions and hold significant implications for their engineering applications.

Insight into Dynamic Recrystallization of AZ31B Magnesium Alloys by Phase-Field Simulations
XU Ke, SHENG Jie, LIU Yu, HUANG Houbing, SHI Xiaoming, SONG Haifeng
2024, 38(3): 030105.   doi: 10.11858/gywlxb.20230780

Magnesium is widely used for materials science, aerospace, and military equipment. It is found that the mechanical property of magnesium under deformation loading is closely related to discontinuous dynamic recrystallization. In this work, we construct a dynamic recrystallization phenomenological model of magnesium alloy via phase-field methods. We choose AZ31B magnesium alloy as the research object and simulate grains and grain boundaries evolutions during dynamic recrystallization under 0.01–1.00 s−1 and 250–400 ℃. Iterative solving methods of stress-strain curves and recrystallization evolutions are improved by introducing plastic deformation energy to phase-field model. The simulation results show the volume fraction of recrystallization grains and the average grain size of samples increase with the rise of temperature and decrease of strain rates.

Molecular Dynamics Simulation Study on Spallation Failure of [100] Single Crystal Aluminum under Different Waveform Loadings
YANG Xiangyang, WU Dun, ZHU Youlin, LI Junguo, ZHANG Ruizhi, ZHANG Jian, LUO Guoqiang
2024, 38(3): 030106.   doi: 10.11858/gywlxb.20240786

In this study, molecular dynamics method was used to simulate the deformation and spallation behavior of [100] single crystal aluminum under the action of equivalent ramp waves and square waves. Accordingly, the correlation between loading waveform and spallation behavior was analyzed. The results showed that the synergistic effect of the pulse shape transition and the thermodynamic path affected the material spallation. The nucleation of non-uniform holes dominated by defects was not the decisive factor affecting the spallation strength of materials. The difference of spallation characteristics of materials under different loading waveforms was mainly determined by the difference of temperature rise under different thermodynamic paths, which led to uniform spallation at maximum velocity of 3.00 km/s, but the spall strength of ramp wave group was 56.6% higher than that of square wave group. Due to the gradual compression and slight temperature softening effect, the ramp wave loading made the material presented milder damage than the impact loading, which became more significant with the increase of loading speed.

Generalized Stacking Fault Energies of Diamond and Silicon under ⟨111⟩ Uniaxial Loading
HUANG Lili, PENG Li, CHEN Shi, ZHANG Hongping, LI Mu
2024, 38(3): 030107.   doi: 10.11858/gywlxb.20240765

The energy caused by atomic level shear in a crystal is called generalized fault energy (GSFE), This is an important material property for describing nanoscale plastic phenomena in crystalline materials, such as dislocation decomposition, nucleation, and twinning. During the shock loading process, the elastoplastic transition occurs after one-dimensional elastic strain, so the generalized stacking fault energy is of great significance in understanding the occurrence of plastic flow. Here, we calculate the generalized GSFE surface of glide (111) surface of silicon and diamond under uniaxial strain in [111] direction by using the first principles of density functional theory. Based on the translation symmetry of GSFE surface, we fit the GSFE surface expression obtained by Fourier series expansion and the generalized stacking fault energy curves for the $ [{\overline{1}10}] $ (111) and $ [ 11\overline{2}]$ (111) directions are given. With the increase of strain, the intrinsic fault energy (γI) and the unstable fault energy (γus) have obvious changes, and the ratio of the unstable stacking fault energy to the intrinsic stacking fault energy (γus/γI) decreases indicating that dislocations in crystals are not easily decomposed under uniaxial strain in the $ \left\langle{111}\right\rangle $ direction. This result explains the results of dynamic experiments of dislocation evolution at four generations of light sources that the speed and strength of fault signals loaded along $ \left\langle{111}\right\rangle $ direction are much lower than those loaded along $ \left\langle{110}\right\rangle $ direction and $ \left\langle{100}\right\rangle $ direction.

Structural Stability and Shock Decomposition of UH3 at High Temperature and High Pressure
WANG Yufeng, HAO Long, WU Fengchao, GENG Huayun, LI Jun
2024, 38(3): 030108.   doi: 10.11858/gywlxb.20240709

Using statistical physical model, the equation of state of UH3 crystal and its chemical decomposition products were constructed in this paper. The phase diagram of UH3 at high temperature and high pressure was obtained by Gibbs free energy comparison, and the shock compression properties of UH3 with different initial densities were investigated. The results show that the chemical decomposition of UH3 crystals occurs at about 74.0 GPa under isothermal compression. Increasing the temperature promotes the chemical decomposition, but the influence of pressure on the chemical decomposition of UH3 is non-monotonic. Solid UH3 decomposes at 35–50 GPa under shock compression, and the chemical decomposition process is accompanied by obvious volume collapse, therefore, the Hugoniot of UH3 decomposition products lies below the isotherm, which is an abnormal phenomenon in comparison with ordinary metals or compounds. Moreover, the decomposition pressure of UH3 decreases with the increase of initial porosity. When the initial porosity is about 1.5, the decomposition products of UH3 are more difficult to compress than UH3 in crystal phase, thus showing a phenomenon similar to the abnormal expansion of large porosity materials under shock compression. These results enrich our understanding of dynamical compression behavior of UH3, and can serve as theoretical basis for further research on physical and chemical properties of actinide metal hydrides at high temperature and high pressure.

Experimental Research Progress on Physical Properties and “Phase Transition” of Polymers under Impact Loading
YE Shijia, HAO Long, WANG Yufeng, LI Shourui, GENG Huayun, LI Jun
2024, 38(3): 030109.   doi: 10.11858/gywlxb.20230787

Polymers are widely used in various fields of national defense and national economy. They are inevitably exposed to extreme conditions of high temperature and high pressure during applying. Thus, it is necessary to study their physical properties and “phase transition” under impact loading. Because of their characteristic molecular chain structure, polymers show different properties from most materials such as metals. The intercept extrapolated from Hugoniot curve at low pressure is obviously higher than their body sound velocity at atmospheric pressure. The wave profile at low pressure presents a structure with an arc shape. At 20–30 GPa, the Hugoniot line turns obviously, indicating that the material has undergone a “phase transition” under impact loading. The “phase transition” is explained as chemical decomposition or lattice structure transformation, and the kinetics of “phase transition” is studied. In addition, the modeling method of equation of state based on chemical decomposition is briefly introduced. Finally, the prospect is put forward according to the doubtful points in the study of physical properties and “phase transition” of polymers under impact loading.

Mid- and Far-Infrared Spectroscopic and First-Principles Computational Study of the Structural Evolution of Hydrazine Nitrate under High Pressure
ZENG Yangyang, ZHU Gangbei, WANG Wentao, BAI Sha, ZHENG Zhaoyang, YU Guoyang, YANG Yanqiang
2024, 38(3): 030110.   doi: 10.11858/gywlxb.20230804

For energetic materials, the lattice vibration modes in the 6 THz (200 cm−1) range are very sensitive to structural changes caused by external temperature and pressure changes. Therefore, mid- and far-infrared vibrational spectroscopy can be used as a powerful tool to study high-pressure phase transitions in these materials. We have obtained high-pressure vibrational spectra of hydrazine nitrate, using mid- and far-infrared ultra-broadband spectroscopy, whose broadband was generated by air plasma, combined with a diamond anvil cell (DAC). The crystal structure of hydrazine nitrate, as well as the infrared spectrum, were calculated by using the first principle method. Based on the calculation, the intermolecular interactions were analyzed. Combined with the experimental results, it was revealed that the structural changes under pressure alter the strength of intermolecular hydrogen bonds and van der Waals interactions, which in turn affects the low-frequency vibrational modes. And by analyzing the vibrational spectra, we observed the phase transition process of hydrazine nitrate.

Application of the High-Pressure Neutron Diffractometer at CMRR in Materials Research
SUN Jiacheng, CHEN Xiping, XIE Lei, FANG Leiming
2024, 38(3): 030111.   doi: 10.11858/gywlxb.20230790

High pressure neutron diffractometer (HPND), also known as FENGHUANG, at China Mianyang Research Reactor’s (CMRR) neutron science platform, which include neutron focusing system, detector system, high-pressure devices and integrated system, can be constructed to in situ neutron diffraction experiments under ambient, high/low temperature, and high-pressure conditions. For in situ high-pressure neutron diffraction experiments, the pressure can reach to over 30 GPa at room temperature, and 10 GPa at 2000 K. FENGHUANG diffractometer has been widely applied in the field of materials researches, to provide precise information on atomic occupation, magnetic structure, crystalline structure and phase transitions, such as transition-metal nitrides, Li-containing materials, magnetic materials, energetic materials, ferroelectric ceramics.

Invited Article and General Review
Pressure Calibration Method of 28 GPa for Large-Volume Press
GE Yufei, YOU Cun, WANG Xinglin, LIAN Min, ZHAO Xinyu, FENG Bingtao, MA Xiaoci, TAO Qiang, HU Kuo, LIU Zhaodong, ZHOU Qiang, ZHU Pinwen
2024, 38(3): 030201.   doi: 10.11858/gywlxb.20230807

In the large-volume press (LVP), the pressure calibration for the sample chamber is generally carried out by using phase transitions of specific materials with resistance changes. But there are no suitable materials for pressure calibration in the range of 22.5−34.5 GPa. As we know, the mineral 50 mol%MgSiO3-50 mol%Al2O3 (En50Cor50) systems in deep earth undergo structural transition to perovskite phase under high pressure and high temperature (HPHT) conditions. Moreover, the content of Al2O3 dissolved in perovskite MgSiO3 increases gradually with raised pressure above 27 GPa. Therefore, En50Cor50 was selected as the pressure calibration material for further calibrating 28 GPa in the LVP in this study, and this is an indirect pressure calibration method. First, the low-pressure calibration curve (6.0−22.5 GPa) of system oil pressure versus chamber pressure was obtained by using the phase transitions of different pressure calibration materials. Then, based on the low-pressure calibration curve and previous research results En50Cor50, the estimated system oil pressure corresponding to the 28 GPa of chamber pressure is 65 MPa. At the estimated oil pressure, the En50Cor50 samples were heated to 2000 K and maintained for 3−7 h. The results of X-ray diffraction, Raman, and electron probe measurements indicate that bridgmanite has been successfully synthesized, and the dissolved Al2O3 molar fraction is greater than 13.7%. According to the previous research results, the corresponding sample chamber pressure is about 29 GPa. This method successfully calibrated the sample chamber pressure around 28 GPa in the LVP, which fill in the blanks for calibrating this pressure range.

Superionic Iron Alloys in Earth’s Inner Core and Their Effects
HE Yu, SUN Shichuan, LI Heping
2024, 38(3): 030202.   doi: 10.11858/gywlxb.20240707

Under the conditions of high temperature and high pressure, a series of materials transform into superionic states, which fall between the solid and liquid states and are widely believed to exist in the interior of Earth and exoplanets. Computational research has found that under the temperature and pressure of the Earth’s inner core, iron-hydrogen, iron-carbon, and iron-oxygen alloys transform to superionic states, manifested as elements such as hydrogen, carbon, and oxygen flowing rapidly like liquids in solid iron alloys. The flowing light elements cause softening of Fe alloys and a decrease in seismic wave velocities, explaining the characteristics of core density deficient and low shear wave velocity observed in geophysics. The superionic iron-hydrogen alloy in the core can interact with the geomagnetic field, forming a lattice preferred orientation fiber driven by a dipole geomagnetic field, explaining the origin of the anisotropic structure in the inner core. The discovery of superionic iron-light-element alloys in the inner core has updated our understanding of the state of the inner core, and is of great significance for understanding the structure, composition, and evolution of Earth’s inner core, as well as the relationship between the inner core structure and the Earth’s magnetic field.

Dynamic Response of Matter
Constitutive Relationship of Q245R Steel of Carbonization Kettle under Thermal Corrosion and Thermal Shocking
LIU Zhiyuan, CHEN Wenfei, XIE Zuoran, JIANG Haocheng, LI Jin, ZHU Jue
2024, 38(3): 034101.   doi: 10.11858/gywlxb.20230813

An electrochemical accelerated corrosion test was conducted on the Q245R steel sample to simulate the actual corrosion conditions of the carbonization kettle. It was found that corrosion not only causes changes in geometric dimensions, but also causes degradation of the material’s mechanical properties. Tensile tests were conducted on Q235R steel materials at different temperatures, corrosion rates, and strain rates (low strain rate of 10−3−1 s−1, medium strain rate of 10−102 s−1, and high strain rate of 103 s−1). A fitting method was carried out based on the modified Johnson-Cook constitutive equation and MATLAB software, which provides the relationship between its characteristic strength, heat treatment temperature and corrosion rate. According to the results, it can be seen that the fitting curve is in good agreement with the experimental curve.

Synergistic Effects of “Carbon Fibre-Graphene” Hybrid Systems and Microwave Post-Treatment Processes on the Mechanics of 3D Printed Polyurethane Composites
WANG Jiuqiang, LI Yongcun, LIU Chaoyang, LEI Keming, GUO Zhangxin, LUAN Yunbo
2024, 38(3): 034102.   doi: 10.11858/gywlxb.20230814

The 3D printing manufacturing process and mechanical behaviors of “carbon fiber-graphene” (CF-G) reinforced thermoplastic polyurethane (TPU) composites were investigated. The CF-G reinforced TPU composite filaments were prepared by the screw extrusion process, then the G+CF/TPU composites were manufactured by the fused deposition modeling (FDM) technology and microwave post-treatment process. It shows that the CF-G heterostructure can synergistically enhance the mechanical properties of TPU composites. Especially, by adopting the novel microwave post-treatment process, the G+CF/TPU specimens exhibited the further improved tensile strength and toughness, which may be attributed to the promoted interface bonding between the reinforcing phase and matrix, and the reduced internal defects between points, layers, and channels induced by the synergistic effect between the CF-G heterostructure and microwave. This study has positive significance for exploring the mechanical reinforcement and post-treatment processes of 3D printed materials.

Numerical Investigation on Damage and Failure of UHPC Targets Subjected to Dislocation Multi-Attacks
ZONG Xianghua, WANG Yin, KONG Xiangzhen, JIANG Yating, SUN Liuyang, YUAN Juncheng, YANG Taochun
2024, 38(3): 034201.   doi: 10.11858/gywlxb.20230834

Based on the LS-DYNA three-dimensional numerical modeling method and the modified Kong-Fang concrete material model, the numerical investigation on damage and failure of ultra-high performance concrete (UHPC) targets subjected to dislocation multi-attacks was carried considering the two-dimensional normal distribution of strike points. The numerical model and material models along with the corresponding parameters were firstly validated by comparing the numerical simulation results of the UHPC targets subjected to projectile penetration followed by explosion to the corresponding test data. Then numerical simulation of the damage and failure in UHPC targets under the multi-attacks by a typical warhead were conducted with 10 groups different circular error probable (CEP) to discuss the effects of the CEP and strike times on the damage and penetration depth. The numerical results demonstrate that the damage evolution caused by the subsequent projectile penetration and explosion continues to develop along the damage area caused by the first projectile penetration. The penetration depth gradually increases as the number of strike increases. The penetration depth calculated with explosion is larger than that calculated without explosion when the CEP is same during multi-attacks. When CEP is equal to 3 m and 1 m, the relative penetration depth is about 1.2 and 1.7, respectively. In other words, the relative penetration depth increased with decreasing of the CEP. The research conclusion shows that the design method of shielding layer thickness in the existing protective design code is dangerous subjected to multi-attacks.

High Pressure Applications
Influences of HMX Content on the Impact Sensitivity and Non-Shock Initiation Reaction Characteristics of PBT Based Propellants
YANG Nian, MA Teng, GUO Guangfei, WU Sanzhen, XIA Yu, HUANG Yinsheng, LIU Dabin, XU Sen
2024, 38(3): 035201.   doi: 10.11858/gywlxb.20230824

In order to investigate the effect of HMX content on the impact sensitivity and non-shock initiation reaction characteristics of PBT based propellants, BAM impact sensitivity tests, friability tests and Susan tests were carried out. The experimental results show that with the increase of HMX content, the characteristic drop height of PBT based propellants at 50% explosion probability (H50) decreases, indicating that the impact sensitivity increases with higher HMX content. In friability tests, the critical non-shock initiation velocities for the PBT based propellants with the HMX mass fraction of 0, 5%, 10%, and 15% are 168, 147, 136, and 131 m/s, respectively, showing a decline in the critical non-shock initiation velocity as HMX content rises. In Susan tests, four different kinds of PBT based propellants react as explosion or partial detonation at velocities range of 120 m/s to 300 m/s. The PBT based propellant with the HMX mass fraction of 10% exhibits more intense reactions compared to the other three PBT based propellants at the same velocity.

Evolution Law of Hydrogen Detonation Cellular Structure under the Effect of Rigid and Flexible Porous Materials
LUO Rongqin, PENG Ao, ZHANG Jingwen, WANG Jun, CHEN Xianfeng, SHEN Liyuan, SHI Jihao, SUN Xuxu
2024, 38(3): 035202.   doi: 10.11858/gywlxb.20230776

As highly efficient absorbing and dissipating materials, porous materials were widely used in the study of detonation wave attenuation. In order to further explore the mechanism of explosion suppression by porous materials, the effects of typical flexible (sponge) and rigid (wire mesh) porous materials on the detonation cellular structure for hydrogen and oxygen mixture were investigated systematically. The effects of thickness and porosity of sponge and wire mesh on the structure and size of detonation cell were discussed in detail. The cellular pattern of detonation wave was recorded by using smoke plate technology, and the cell size was calculated. The pressure sensors were used to record the arrival time of the detonation wave, and the average propagation velocity of detonation wave was obtained. The results show that the detonation cellular structure closely depends on the thickness and porosity of sponge and wire mesh, and three phases of the propagation can be observed in the tube, including detonation failure, acceleration and re-initiation. In addition, size of the detonation cell is also closely related to the thickness and porosity of sponge and wire mesh. Increasing the thickness of porous materials and decreasing the porosity both can increase the size of the detonation cell. By comparing the effects of sponge and wire mesh on the detonation cellular structure, it can be found that at the same initial condition, the rigid porous material has a stronger inhibition effect on detonation. But the difference will be gradually decreased with the increase of the thickness of the porous materials. Finally, the limit of the detonation propagation is analyzed quantitatively by introducing the dimensionless parameter DH. For flexible and rigid porous materials, the detonation limit can be nearly quantified as DH≈3.0 and DH≈3.1.

Slope Stability Prediction Based on WOA-RF Hybrid Model
ZHANG Jiantao, LIU Zhixiang, ZHANG Shuangxia, GUO Tengfei, YUAN Congxiang
2024, 38(3): 035301.   doi: 10.11858/gywlxb.20230837

To effectively predict slope stability and prevent slope instability occurrence, a hybrid model WOA-RF, combining whale optimization algorithm (WOA) and random forest (RF) was proposed. Based on the collected slope cases, the classification and generalization performance of the model was evaluated according to the classification performance indicators given by the confusion matrix and the area under the receiver operating characteristic curve. Additionally, WOA was used to optimize four widely used machine learning models, and the optimized machine learning models were compared with WOA-RF. The results demonstrate that WOA is effective in optimizing hyperparameters and improving model performance. The optimal WOA-RF model achieves an accuracy of 0.99 on training set and of 0.94 on test set. After optimization, the accuracy, the precision, the recall, and the hamonic mean of the precision and recall are increased by 11.9%, 19.0%, 4.8%, and 11.9%, respectively. Comparative analysis reveals that the WOA-RF model is superior to the others in all indicators. Furthermore, the feature importance ranking was determined. Analysis of the feature importance indicates that unit weight is the most sensitive feature affecting slope stability. The established WOA-RF model is proved effective in predicting slope stability and facilitating the development of appropriate protective measures based on the predicted results.

Experimental Study of the Effect of Shear Stress on Phase Transition in c-Axis CdS Single Crystal under Dynamic Loading
TANG Zhi-Ping, Gupta Y M
1989, 3(4): 290-297 .   doi: 10.11858/gywlxb.1989.04.005
[Abstract](13570) [PDF 8643KB](2215)
For a long time, the problem whether shear stress affects the phase transition initial pressure is not well solved. Duvall and Graham suggested that cadmium sulfide (CdS) crystal could be used to study the effect of shear stress on the initial pressure of phase transition in c-axis CdS single crystal specimens under high velocity impact systematically. The axial stress of initial phase transition measured is T=(3.250.1) GPa, corresponding to a mean pressure pT=(2.290.07) GPa, which agrees the value 2.3 GPa of static results quite well within the experimental error. The shear stress in this case, T=0.72 GPa, is as high as 31.5% of the mean pressure. This result shows that the mechanism of phase transition may be assumed only to relate to a critical mean pressure or critical thermodynamic state, and the effect of shear stress can be ignored.
Flattening of Cylindrical Shells under External Uniform Pressure at Creep
Shesterikov S A, Lokochtchenko A M
1992, 6(4): 247-253 .   doi: 10.11858/gywlxb.1992.04.002
[Abstract](9518) [PDF 2836KB](1967)
Experimental studies of the deformation of cylindrical shells under creep to fracture conditions are described in this paper. Analyses of three series of test shells are given and experimental and theoretical results are compared with each other.
The Generation of 90 GPa Quasi-Hydrostatic Pressures and the Measurements of Pressure Distribution
LIU Zhen-Xian, CUI Qi-Liang, ZOU Guang-Tian
1989, 3(4): 284-289 .   doi: 10.11858/gywlxb.1989.04.004
[Abstract](15398) [PDF 6073KB](2626)
Quasi-hydrostatic pressures up to 90 GPa were obtained at room temperature in the diamond cell by using solid argon as pressure medium. The pressure distribution was determined by measuring the special shift of the R1 line of ruby at different positions within the sample chamber. Experimental results showed that the pressure differences (p) between the pressures at each point within the chamber and the mean pressure (p) were very small, ratios of p/p were less than 1.5% when below 80 GPa. The shape of ruby R lines at 90 GPa is similar to that at ambient pressure. Thus, quasi-hydrostatic pressure near 100 GPa can be obtained by using solid argon as pressure medium. Moreover, the red shifts with pressures of the peak positions at 14 938 and 14 431 cm-1 in ruby emission spectra, were also examined. It concluded that the line, 14 938 cm-1, can be adopted in the pressure calibration.
A Study on Calculation of the Linear Thermal Expansion Coefficients of Metals
ZHENG Wei-Tao, DING Tao, ZHONG Feng-Lan, ZHANG Jian-Min, ZHANG Rui-Lin
1994, 8(4): 302-305 .   doi: 10.11858/gywlxb.1994.04.010
[Abstract](15985) [PDF 1350KB](1110)
Based on the expression of pressure at temperature T and in terms of the universal equation of state Debye model and the thermodynamic relations, a general expression for the calculation of the linear thermal expansion coefficients of metals is obtained. This formula applied to the calculation of Al, Cu, Pb. Calculated results are in good agreement with the experiments.
Development of Large Volume-High Static Pressure Techniques Based on the Hinge-Type Cubic Presses
WANG Hai-Kuo, HE Duan-Wei, XU Chao, GUAN Jun-Wei, WANG Wen-Dan, KOU Zi-Li, PENG Fang
2013, 27(5): 633-661.   doi: 10.11858/gywlxb.2013.05.001
[Abstract](14120) [PDF 12118KB](1000)
The large volume press (LVP) becomes more and more popular with the scientific and technological workers in the high pressure area, because it could generate relatively higher pressure, provide better hydrostatic pressure and could be utilized in conjunction with in situ X-ray diffraction, neutron diffraction and ultrasonic measurement. There have been generally two LVP techniques to generate high-pressure: the double-anvil apparatus and the multi-anvil apparatus (MAA). Hinge-type cubic presses, as the main apparatus in china, have been widely used in the fields of both scientific research and diamond industry. However, for a long time past, the maximum pressure using the conventional one-stage anvil system for hinge-type cubic press is about 6 GPa, and the techniques about two-stage apparatus (octahedral press) that could generate pressure exceed 20 GPa is blank in our country. To a certain extent, the backwardness of the LVP technology in china restricts the development of high pressure science and related subjects. In recent years, we designed two kinds of one-stage high pressure apparatus and the two-stage apparatus based on hinge-type cubic-anvil press, the one-stage high pressure apparatus and the two-stage apparatus using cemented carbide as anvils could generate pressures up to about 9 GPa and 20 GPa respectively. This article mainly reviews the mechanics structure, design of cell assembly, pressure and temperature calibration, design and preparation of the sintered diamond anvils and pressure calibration to 35 GPa using sintered diamond as two-stage anvils about the one-stage high pressure apparatus and the two-stage apparatus designed in our laboratory.
Research on Deformation Shape of Deformable Warhead
GONG Bai-Lin, LU Fang-Yun, LI Xiang-Yu
2010, 24(2): 102-106 .   doi: 10.11858/gywlxb.2010.02.004
[Abstract](8342) [PDF 1765KB](325)
Basing on the detonation theory, the structure of the deformable warhead was simplified to be double layer cylindrical shells under the detonation. Plastic hinges were introduced into the loading section of the shell, which contacted with the deforming charge, and the deforming charge was divided into small segments accordingly. Loading and movement of these segments were analyzed. Deforming shape of the cylindrical shell under the loading with equal distribution was bulgy, and the displacement of shell segments was obtained. Deforming charge with different thickness, according to the displacement of the segment, was set up to realize the same displacement of the shell segments on the loading direction. The D-shape was achieved theoretically, and the shape of deforming charge was designed accordingly. Numerical simulation validated the feasibility of the designed plan. The results indicate that the deformable warhead with the new-designed deforming charge can realize the D-shape.
The Failure Strength Parameters of HJC and RHT Concrete Constitutive Models
ZHANG Ruo-Qi, DING Yu-Qing, TANG Wen-Hui, RAN Xian-Wen
2011, 25(1): 15-22 .   doi: 10.11858/gywlxb.2011.01.003
[Abstract](17207) [PDF 689KB](986)
The analyzed and calculated results indicate that the concrete failure strength will decrease under higher hydrostatic pressure, when the original failure parameters of HJC and RHT models implemented in LS-DYNA and AUTODYN are adopted. A new method is introduced which using the characteristic strength of concrete to confirm the modified failure parameters of HJC and RHT models. The same physical experiment of concrete penetration was simulated using the modified HJC and RHT failure parameters respectively, and the numerical results demonstrated that the RHT model matched the experiments much better. But the numerical results with the HJC modified failure parameters were not enough satisfied, because the third invariant of the deviated stress tensor was not considered in the HJC model.
Modification of Tuler-Butcher Model with Damage Influence
JIANG Dong, LI Yong-Chi, GUO Yang
2009, 23(4): 271-276 .   doi: 10.11858/gywlxb.2009.04.006
[Abstract](10762) [PDF 402KB](783)
A modificatin of Tuler-Butcher model including damage influence was presented, which was incorporated into a hydrodynamic one-dimensional finite difference computer code, to simulate the process of spall fracture of 45 steel and Al-Li alloy. The calculated results are in good agreement with experimental data, and shows the correctness of the model.
Recent Progresses in Some Fields of High-Pressure Physics Relevant to Earth Sciences Achieved by Chinese Scientists
LIU Xi, DAI Li-Dong, DENG Li-Wei, FAN Da-Wei, LIU Qiong, NI Huai-Wei, SUN Qiang, WU Xiang, YANG Xiao-Zhi, ZHAI Shuang-Meng, ZHANG Bao-Hua, ZHANG Li, LI He-Ping
2017, 31(6): 657-681.   doi: 10.11858/gywlxb.2017.06.001
[Abstract](11035) [FullText HTML](4707) [PDF 2527KB](4707)

In the last 10 years or so, nearly all major Chinese universities, schools and research institutes with strong Earth science programs showed strong interest in developing a new research branch of High-Pressure Earth Sciences.As a result, many young Chinese scientists with good training from the universities in the west countries were recruited.This directly led to a fast growing period of about 10 years for the Chinese high-pressure mineral physics research field.Here we take the advantage of celebrating the 30th anniversary of launching the Chinese Journal of High Pressure Physics, and present a brief summary of the new accomplishments made by the Chinese scientists in the fields of high-pressure mineral physics relevant to Earth sciences.The research fields include:(1) phase transitions in the lower mantle; (2) high spin-low spin transitions of iron in lower mantle minerals; (3) physical properties of the Earth core; (4) electrical measurements of rocks; (5) electrical measurements of minerals; (6) elasticity of minerals (especially equation of states); (7) high-pressure spectroscopic studies; (8) chemical diffusions in minerals; (9) ultrasonic measurements under high pressure; (10) physical properties of silicate melts; (11) geological fluids.In sum, the last 10 years have seen a rapid development of the Chinese high-pressure mineral physics, with the number of scientific papers increasing enormously and the impact of the scientific findings enhancing significantly.With this good start, the next 10 years will be critical and require all Chinese scientists in the research field to play active roles in their scientific activities, if a higher and advanced level is the goal for the Chinese mineral physics community.

Experiment and Numerical Simulation of Cylindrical Explosive Isostatic Pressing
CHEN Lang, LU Jian-Ying, ZHANG Ming, HAN Chao, FENG Chang-Gen
2008, 22(2): 113-117 .   doi: 10.11858/gywlxb.2008.02.001
[Abstract](13618) [PDF 1180KB](818)
The experiments of cylindrical explosive isostatic pressing were carried out. The internal temperatures in pressed explosives were measured by thermocouples. A thermal/structural coupled model of the explosive isostatic pressing was set up. The numerical simulations of cylindrical explosive were conducted. The calculated pressures and temperatures in explosives were given. The deformations,pressures and temperatures distribution were analyzed. The calculated results indicated that each surface center of the cylindrical explosive was sunken by isostatic pressing. During the isostatic pressing of cylindrical explosive, the internal temperature of the explosives increases, and the temperature and pressure are not uniform.
Perimeter-Area Relation of Fractal Island
1990, 4(4): 259-262 .   doi: 10.11858/gywlxb.1990.04.004
[Abstract](15696) [PDF 1508KB](2351)
The relationship of perimeter with area (P/A relation) of fractal island is discussed. It is shown that Mandelbrot's fractal relation between Koch perimeter and area does not hold in the island with finite self-similar generations. This might be the reason why the fractal dimension measured with P/A relation varied with the length of yardstick in previous work.
Long-Distance Flight Performances of Spherical Fragments
TAN Duo-Wang, WEN Dian-Ying, ZHANG Zhong-Bin, YU Chuan, XIE Pan-Hai
2002, 16(4): 271-275 .   doi: 10.11858/gywlxb.2002.04.006
[Abstract](14214) [PDF 2450KB](877)
Using two-stage light gas gun and laser technique for velocity easurement, we studied the long-distance flight performances of spherical fragments with different materials and different diameters. The flight distance is 60~120 m, and the initial velocity is 1.2~2.2 km/s. The experimental results show that: (1) the velocity attenuation coefficient of spherical fragment is constant, and (2) the air drag coefficient is slightly affected by the initial velocity of spherical fragment, the air drag coefficient is a linear function of initial velocity.
Factors Analysis of Debris Cloud's Shape of Hypervelocity Impact
TANG Mi, BAI Jing-Song, LI Ping, ZHANG Zhan-Ji
2007, 21(4): 425-432 .   doi: 10.11858/gywlxb.2007.04.016
[Abstract](13357) [PDF 1599KB](726)
The numerical simulations of hypervelocity impact of Al-spheres on bumper at normal are carried out using the smoothed particle hydrodynamics (SPH) technique. The simulation results are compared with experimental results, and the simulated hole diameters of bumper and debris cloud are well consistent with experimental results. The effect of impact velocity, bumper thickness, projectile diameter, materials, shape of projectile, interval on produced debris cloud are further analyzed. Regarding the length and diameter as index, orthogonal design method is applied to analyze the primary and secondary relations on the debris cloud's index of the three factors, that is impact velocity, bumper thickness and projectile diameter. The results indicate that bumper thickness is the main influence factor of debris cloud's length while projectile diameter is the main influence factor of debris cloud's diameter.
Design of the Sample Assembly for Ultrasonic Measurement at High Pressure and 300 K in Six-Side Anvil Cell
WANG Qing-Song, WANG Zhi-Gang, BI Yan
2006, 20(3): 331-336 .   doi: 10.11858/gywlxb.2006.03.019
[Abstract](10869) [PDF 411KB](647)
We introduced briefly the principle of design of sample assembly for ultrasonic measurements at high pressure, and designed a new kind of sample assembly to measure the isothermal compression of Al and Cu at 300 K. Ideal quasi-hydrostatic loading was realized, and high-quality ultrasonic signals were obtained under high pressure. It was indicated that the design of sample assembly was reasonable. We analyzed in brief main uncertainty of ultrasonic measurement in six-side anvil cell at 300 K.
Detonation Shock Dynamics Calibration of JB-9014 Explosive at Ambient Temperature
TAN Duo-Wang, FANG Qing, ZHANG Guang-Sheng, HE Zhi
2009, 23(3): 161-166 .   doi: 10.11858/gywlxb.2009.03.001
[Abstract](14232) [PDF 794KB](818)
Detonation shock dynamics (DSD) is an approximation to the reactive Euler equations that allows numerically efficient tracking of curved detonation waves. The DSD parameters are the velocity curvature relation and the boundary angle. A computer code was developed to facilitate the calibration of these parameters for JB-9014 insensitive high explosive using the generalized optics model of DSD. Calibration data were obtained from measurements of the detonation velocities and fronts in JB-9014 rate sticks at ambient temperature, with diameters of 10~30 mm. The steady state detonation velocities and fronts predicted by these DSD parameters are in very good agreement with experiment.
Shock Wave Physics: The Coming Challenges and Exciting Opportunities in the New Century-Introduction of the 12th International Conference of Shock Compression of Condensed Matter (SCCM-2001)
GONG Zi-Zheng
2002, 16(2): 152-160 .   doi: 10.11858/gywlxb.2002.02.012
[Abstract](14186) [PDF 500KB](872)
The 12th Biennial International Conference of the APS Topical Group on Shock Compression of Condensed Matter (SCCM-2001) was introduced. Papers presented in SCCM-2001 were surveyed and the recent progresses on shock compression of condensed matter were retrospected. The basic paradigms and the great achievements of the physics and mechanics of condensed matter at high dynamic pressure and stress were surveyed and revaluated. The coming challenges and exciting opportunities of shock wave physics in the 21 century were prospected.
Design and Temperature Calibration for Heater Cell of Split-Sphere High Pressure Apparatus Based on the Hinge-Type Cubic-Anvil Press
CHEN Xiao-Fang, HE Duan-Wei, WANG Fu-Long, ZHANG Jian, LI Yong-Jun, FANG Lei-Ming, LEI Li, KOU Zi-Li
2009, 23(2): 98-104 .   doi: 10.11858/gywlxb.2009.02.004
[Abstract](14789) [PDF 4054KB](827)
A new type of heater cell for the split-sphere high pressure apparatus based on the hinge-type cubic-anvil press was reported. This heating apparatus has the advantages of being simple, low cost, fast temperature rising, good heat insulation, and the temperature signal can be easily extracted. Carbon tube was used as a heating element for side-heating in our experiments. The size of the sample in the cell can reach 3 mm in diameter, and 7 mm in height. The relationship between the heating electric power and cell temperature was calibrated with Pt6%Rh-Pt30%Rt thermocouples under different pressures. The experimental results indicate that the temperature can reach 1 700 ℃ under the oil hydraulic pressure of 40 MPa (cell pressure is about 10 GPa).The temperature can keep stable for more than 2 h under a fixed power.
The Constitutive Relationship between High Pressure-High Strain Rate and Low Pressure-High Strain Rate Experiment
CHEN Da-Nian, LIU Guo-Qing, YU Yu-Ying, WANG Huan-Ran, XIE Shu-Gang
2005, 19(3): 193-200 .   doi: 10.11858/gywlxb.2005.03.001
[Abstract](10755) [PDF 416KB](787)
It is indicated that the constitutive equations at high strain rates proposed by Johnson-Cook(J-C), Zerilli-Armstrong (Z-A) and Bodner-Parton (B-P) collapse the data of flow stress in compression, tension, torsion, and shear into simple curve with the scalar quatities 'effective' stress and 'effective' strain, however, the collapsed data of flow stress did not include the data in the planar shock wave tests. The SCG constitutive equation proposed by Steinberg et al for the planar shock wave tests is discussed, which describes the coupled high pressure and high strain rate effects on the plastic deformation of materials. Basing on the recent experiments at elevated temperatures and high strain rates and the shear strength measurements during shock loading, the flow stress for tungsten at high pressure and high strain rates is estimated with J-C and SCG constitutive equations, respectively. It is concluded that the J-C, Z-A and B-P constitutive equations may not be appropriate to describe the plastic behavior of materials at high pressure and high strain rates, comparing with SCG constitutive equation. It is emphasized that the physical background of the constitutive equation at high pressure and high strain rates is different from that at low pressure and high strain rates.
Explosive Shock Synthesis of Wurtzite Type Boron Nitride
TAN Hua, HAN Jun-Wan, WANG Xiao-Jiang, SU Lin-Xiang, LIU Li, LIU Jiang, CUI Ling
1991, 5(4): 241-253 .   doi: 10.11858/gywlxb.1991.04.001
[Abstract](11997) [PDF 4689KB](2145)
Reported in the paper are techniques of wurtzite type boron nitride (wBN) synthesis from graphite type BN (gBN) by means of shock compressions created via explosive detonation. Recovered samples after shock processing are treated with molten alkalis and hydrochloric acid. Despite that the domestic gBN materials we used are far inferior, both in the crystallinities and particle sizes, to those used in foreign countries for the purpose of shock synthesis of wBN, the yield of our wBN reaches 11 to 12 g per shot, with a convertion ratio over 50%; X-ray diffraction and x-ray fluorescence spectrometry analyses reveal that the total impurity content of this chemically extracted wurtzite type boron nitride product is less than 0.5%. Four different starting gBN from different manufacturers were used in the experiments to synthesis wBN under the same conditions of shock compressions. It is found that the yield of wBN is closely related to the crystallinity of the starting gBN materials. Specific area measurements and XRD analysis indicate that our wBN is a polycrystal super-fine powder material with average particle size of 0.1 m, which consists of many primary crystallites of 17.5 nm in dimension. Thermal stability of our wBN powder is characterized by the emergence of an exothermic peak in the atmospheric gas condition from DTA analysis. Initial temperature of this exothermic reaction is about 1 055 K and peak temperature 1 238 K.
Phase Evolution of Zr-Based Bulk Metallic Glass Prepared by Shock-Wave Quenching under High Temperature and High Pressure
YANG Chao, CHEN Wei-Ping, ZHAN Zai-Ji, JIANG Jian-Zhong
2007, 21(3): 283-288 .   doi: 10.11858/gywlxb.2007.03.011
[Abstract](14013) [PDF 534KB](712)
Phase evolution (PH) of Zr41Ti14Cu12.5Ni10Be22.5 bulk metallic glass (BMG) prepared by shock-wave quenching has been studied under high-temperature and high-pressure using in situ synchrotron radiation energy-dispersive X-ray diffraction. The results show that the primarily precipitated phase is Zr2Be17 at applied pressures, but the subsequent PH processes are different. The crystallization temperature increases with pressure, but with a sudden drop at about 6.0 GPa. Compared with experimental results of the BMG prepared by water quenching, it can be concluded that crystallization temperature of the BMGs prepared by shock-wave quenching and water quenching all drop at the same pressure region, at which their PHs are different from those of other pressures. The different PHs and the drop of crystallization temperature may be attributed to that the BMG possesses different atomic configuration at different pressures.

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Editor-in-Chief:ZOU Guangtian