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| 1 | Controlling morphology evolution of AIN nanostructures:influence of growth conditions in physical vapor transport显示文摘A series of AIN nanostructures were synthesized by an ultrahigh-temperature, catalyst-free, physical vapor transport(PVT) process. Energy dispersive X-ray spectroscopy(EDX), X-ray diffraction(XRD), X-Ray photoelectron spectroscopy(XPS),high resolution transmission electron microscopy(HRTEM) detection show that high quality AIN nanowires were prepared. Nanostructures including nanorings, nanosprings, nanohelices, chainlike nanowires, six-fold symmetric nanostructure and rod-like structure were successfully obtained by controlling the growth duration and temperature. The morphology evolution was attributed to electrostatic polar charge model and the crystalline lattice structure of AIN. | Lei Jin Hongjuan Cheng Jianli Chen Song Zhang Yongkuan Xu, and Zhanping Lai | 2018 | Journal of Semiconductors2018，39，7： | 4 |
| 2 | Effect of Acid Rain Erosion on Steel Fiber Reinforced Concrete显示文摘Acid rain can deteriorate the performance of reinforced concrete structure.Combined with the characteristics of acid rain in China,the properties of steel fiber reinforced concrete subjected to acid rain were studied.The effects of steel fiber content and pH value of acid rain on the mass loss,erosion depth,neutralization depth,and splitting tensile strength of tested concrete were investigated.The mercury intrusion pore(MIP) test was used to analyze the influence of steel fiber on the acid rain resistance of concrete matrix.The results show that the corrosion of steel fiber reinforced concrete subjected to acid rain results from the combined effect of H^+ and SO_4^(2-) in the acid rain,and steel fiber can improve the acid rain resistance of the tested concrete by improving the pore structure and enhancing the tie effect of the concrete matrix.The experiment further indicates that the optimum content of steel fiber is 1.5%compared to the various mixing proportion in this tests.The tested concrete mass loss and splitting tensile strength decrease followed by increasing as a function of corrosion time when the pH value of the simulation solution is 3 or 4,while they decrease continuously in the simulation solution at pH 2.Thanks to the tie effect of steel fiber,the spalling of concrete matrix is significantly improved,and the erosion depth and neutralization depth are less than those of conventional concrete. | 王艳 牛荻涛 SONG Zhanping | 2017 | Journal of Wuhan University of Technology(Materials Science)2017，32，1： | 2 |
| 3 | A new energy-absorbing bolt used for large deformation control of tunnel surrounding rock显示文摘In order to control the large deformation of tunnel surrounding rock,a new energy-absorbing bolt is developed.This bolt can be transformed into a rigid support when the deformation of the surrounding rock reaches the length of the sleeve tube,thus preventing the surrounding rock from continuing to deform.Moreover,this bolt has a simple structure and is easy to manufacture and assemble.Then the static tensile test is conducted on the bolt specimen to test its working performance.The test results show that when the cone angle of the cone block is small,the load–displacement curve of the bolt contains three stages;when the cone angle is large,the load–displacement curve contains only two stages.Meanwhile,both the average constant resistance and the maximum absorbed energy increase linearly with the increase of cone angle.On this basis,ignoring the influence of shear stress,and it is supposed that the thickness of the sleeve tube is constant,then the theoretical calculation formula of constant resistance for the new bolt is derived,and the rationality of the formula is verified using the static tensile test results.It is found that the error of the calculated result is less than 15%when the cone angle does not exceed 15.At last,the numerical simulation method is used to analyze the performance of the new bolt.The simulation results indicate that the generation of shear stress and the change of tube thickness during the movement of the cone block are two important factors that cause theoretical errors. | Junbao Wang Wei Liu Zhanping Song Lingfeng Li Shijin Feng Yun Cheng | 2022 | International Journal of Mining Science and Technology2022，32，5： | 1 |
| 4 | Fatigue properties and damage constitutive model of salt rock based on CT scanning显示文摘To investigate the macroscopic fatigue properties and the mesoscopic pore evolution characteristics of salt rock under cyclic loading,fatigue tests under different upper-limit stresses were carried out on salt rock,and the mesoscopic pore structures of salt rock before and after fatigue tests and under different cycle numbers were measured using CT scanning instrument.Based on the test results,the effects of the cycle number and the upper-limit stress on the evolution of cracks,pore morphology,pore number,pore volume,pore size,plane porosity,and volume porosity of salt rock were analyzed.The failure path of salt rock specimens under cyclic loading was analyzed using the distribution law of plane porosity.The damage variable of salt rock under cyclic loading was defined on basis of the variation of volume porosity with cycle number.In order to describe the fatigue deformation behavior of salt rock under cyclic loading,the nonlinear Burgers damage constitutive model was further established.The results show that the model established can better reflect the whole development process of fatigue deformation of salt rock under cyclic loading. | Junbao Wang Xiao Liu Qiang Zhang Xinrong Liu Zhanping Song Shijin Feng | 2024 | International Journal of Mining Science and Technology2024，34，2： | 0 |
| 5 | Photoluminescence Studies on Very High-Density Two-Dimensonal Electron Gases in Pseudomorphic Modulation-Doped Quantum Wells显示文摘We present photoluminescence studies on highly dense two-dimensional electron gases in selectively Siδ-doped GaAs/ln_(0.18)Ga_(0.82) As/Al_(0.25)Ga_(0.75),As quantum wells(Ns=4.24 × 10^(12) cm^(-2)).Five well-resolved photoluminescence lines centered at 1.4194,1.4506,1.4609,1.4695 and 1.4808eV were observed,which are attributed to the subband exciton emission.The subband separations clearly exhibit the feature of a typical quantum well with triangle and square potential.These very intensive and sharp luminescence peaks with linewidths of 2.2 to 3.5meV indicate the high quality of the structures.Their dependence on the excitation intensity and temperatures are also discussed. | LI Wei WANG Zhanguo LIANG Jiben XU Bo ZHU Zhanping SONG Aimin ZHENG Wanhua YANG Bin | 1994 | Chinese Physics Letters1994，11，12： | 0 |
| 6 | Failure mechanism and infrared radiation characteristic of hard siltstone induced by stratification effect显示文摘The deformation in sedimentary rock induced by train loads has potential threat to the safe operation of tunnels. This study investigated the influence of stratification structure on the infrared radiation and temporal damage mechanism of hard siltstone. The uniaxial compression tests, coupled with acoustic emission(AE) and infrared radiation temperature(IRT) were conducted on siltstones with different stratification effects. The results revealed that the stratigraphic structure significantly affects the stress-strain response and strength degradation characteristics. The mechanical parameters exhibit anisotropy characteristics, and the stratification effect exhibits a negative correlation with the cracking stress and peak stress. The failure modes caused by the stratification effect show remarkable anisotropic features, including splitting failure(Ⅰ: 0°-22.50°, Ⅱ: 90°), composite failure(45°), and shearing failure(67.50°). The AE temporal sequences demonstrate a stepwise response characteristic to the loading stress level. The AE intensity indicates that the stress sensitivity of shearing failure and composite failure is generally greater than that of splitting failure. The IRT field has spatiotemporal migration and progressive dissimilation with stress loading and its dissimilation degree increases under higher stress levels. The stronger the stratification effect, the greater the dissimilation degree of the IRT field. The abnormal characteristic points of average infrared radiation temperature(AIRT) variance at local stress drop and peak stress can be used as early and late precursors to identify fracture instability. Theoretical analysis shows that the competitive relationship between compaction strengthening and fracturing damage intensifies the dissimilation of the infrared thermal field for an increasing stress level. The present study provides a theoretical reference for disaster warnings in hard sedimentary rock mass. | CHENG Yun SONG Zhanping XU Zhiwei YANG Tengtian TIAN Xiaoxu | 2024 | Journal of Mountain Science2024，21，3： | 0 |
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