Papers by Author: Xiao Jie Li

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Authors: Fa Sheng Zhang, Yun Xing Shi, Jing Bin Shi, Kun Ni, Yan Gang Zhang, Xiao Jie Li
Abstract: In order to study the flexural behavior of steel fiber reinforced concrete (SFRC) shield tunnel segment, two full scale shield tunnel segments and twelve reduced scale shield tunnel segments were made and tested. Based on the experiment study, the effectiveness of reduced scale segment was analyzed. Meanwhile, based on the fail mode, load-deflection curves and crack width, the part substitution of steel reinforcement by steel fibers was studied. Test results showed that the reduced scale model can reflect the flexural behavior of full scales tunnel segment and 45kg/m3 steel fibers of 3D type can replace 17% longitudinal reinforcement and 70% stirrups.
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Authors: Xing Hua Xie, Xiao Jie Li, Shi Long Yan, Meng Wang, Ming Xu, Zhi Gang Ma, Hui Liu, Zi Ru Guo
Abstract: This paper describes a new method for prediction of the Chapman–Jouguet detonation parameters of CaHbNcOdLieMnf explosives for mixture of some of low temperature explosion explosives at 0 = 1000 kg/m3. Explosion temperatures of water-gel explosives and explosive formulations are predicted using thermochemistry information. The methodology assumes that the heat of detonation of an explosive compound of products composition H2O–CO2–CO–Li2O–MnO2–Mn2O3 can be approximated as the difference between the heats of formation of the detonation products and that of the explosive, divided by the formula weight of the explosive. For the calculations in which the first set of decomposition products is assumed, predicted temperatures of explosion of water-gel explosives with the product H2O in the gas phase have a deviation of 153.29 K from results with the product H2O in the liquid state. Lithium and manganese oxides have been prepared by the explosion of water-gel explosives of the metal nitrates, M (NO3) x (M = Li, Mn) as oxidizers and glycol as fuels, at relative low temperature. We have also used the Dulong-Petit’s values of the specific heat for liquid phase H2O. Lithium manganese oxide powders with chrysanthemum-like morphology secondary particles, but with smaller primary particles of diameters from 5 to 30 nm and a variety of morphologies were found. The oxides produced by this cheap method affirmed the validity of explosion synthesis of nano-size materials for lithium ion batteries.
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Authors: Wen Zheng Cui, Min Li Bai, Ji Zu Lv, Xiao Jie Li
Abstract: This research applied molecular dynamics method to micro Couette flow of nanofluids, in order to examine the absorption layer near solid surfaces, and propose mechanisms of heat transfer enhancement due to flow. The model of nanofluids consisted of 4 nm Cu nanoparticles and liquid argon as base liquid, Lennard-Jones potential function was adopted to deal with the interactions between atoms. Through visual observation and analysis, it was found that the even-distributed liquid argon atoms near solid surfaces could be seemed as a reform to base liquid and had contributed to heat transfer enhancement. In the process of Couette flow, nanoparticles were rotating and vibrating besides moving translationally. The micro-motions of nanoparticles could disturb the continuity of fluid and strengthen partial flow nearby nanoparticles, and enhance heat transfer in nanofluids.
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Authors: Xiao Hong Wang, Xiao Jie Li, Da Wang, Hong Hao Yan
Abstract: In the present research, a kind of special emulsions explosive was prepared with taking Ferric nitrate and Manganese nitrate as main oxidants and composite oil as fuel, in which the Magnesium and zinc elements were added and doped in Mn ferrites. The results of which were compared by that of detonation of gas (Hydrogen and oxygen). Results indicated that the detonation products were the same structure, i.e. Jacobsite structure. That is to say, Magnesium and zinc elements were successfully doped in MnFe2O4 crystals. TEM indicated that the powders were spherical and average size was about 20~30nm. The product that obtained by gas detonation was better dispersed and worse uniform than that by explosive. Zn and high content Mg both had great effect on the stability and detonation properties of the explosive, which could produce impurities in detonation products.
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Authors: Xiao Jie Li, Ning Luo, Min Li Bai
Abstract: A method for synthesizing carbon-encapsulated metal nanoparticles(CEMNPs) is reported. In the proposed method, a composite precursors containing various nitrate dissolved in absolute ethanol is ignited by a nonelectric detonator in nitrogen gas in an explosion vessel. Upon the completion of detonation reaction, CEMNPs (Fe@C, Ni@C, Co@C) with diameters ranging from a few nanometers to about 20 nm are produced in the explosion vessel.The material characteristics of these nanoparticles are then examined with the XRD, TEM, EDX and VSM, which characterize the feature of morphology, components, phases and magnetism of nano-composite particles. The composite particles whose coating shell were graphite carbon could be dispersed finely. The core of nanoparticles were composed of iron,cobalt and nickel crystal to that of the above explosive precursors.The magnetic analysis indicated that the different composite nanoparticles have good ferromagnetism and superparamagetism in room temperature.
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Authors: Xiao Jie Li, Ning Luo, Hong Hao Yan, Xiao Hong Wang
Abstract: A detonation method for synthesizing carbon-encapsulated metal nanoparticles (CEMNPs) is reported. The composite precursors containing various nitrate dissolved in absolute ethanol is ignited by a nonelectric detonator in nitrogen gas in an explosion vessel. The material characteristics of these nanoparticles are then examined with the XRD,TEM,EDX and RS. The results show that the composite particles whose coating shell were graphite carbon could be dispersed finely. The core of nanoparticles were composed of iron, cobalt and nickel crystal to that of the above explosive precursors.
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Authors: Xiao Jie Li, Xing Hua Xie, Long Jiang Zou, Hong Hao Yan, Yan Dong Qu, Qiang Xu, Xin Ouyang
Abstract: Nanostructured spherical lithium manganese oxide (Li-Mn-O) with about 30nm in diameter was synthesized for the first time by explosive method. The water-solubility explosive was prepared using a simple facility at room temperature. The growth of lithium manganese oxides via detonation reaction was investigated with respect to the presence of an energetic precursor, such as the metallic nitrate and the degree of confinement of the explosive charge. The detonation products were characterized by scanning electron microscopy. Powder X-ray diffraction and transmission electron microscopy were used to characterize the products. Lithium manganese oxides with spherical morphology and more uniform secondary particles, with smaller primary particles of diameters from 10 to 50 nm and a variety of morphologies were found. Lithium manganese oxides with a fine spherical morphology different from that of the normal is formed after detonation wave treatment due to the very high quenching rate. It might also provide a cheap large-scale synthesis method. Explosive detonation is strongly nonequilibrium processes, generating a short duration of high pressure and high temperature. Free metal atoms are first released with the decomposition of explosives, and then theses metal and oxygen atoms are rearranged, coagulated and finally crystallized into lithium manganese oxides during the expansion of detonation process. For detonation of the water-solubility explosive, the detonation pressure, the detonation temperature and the adiabatic gamma were close to 3 GPa, 2300 K and 3. The inherent short duration, high heating rate (1010 – 1011 K/s) and high cooling rate (108 – 109 K/s) prevent the lithium manganese oxides crystallites from growing into larger sizes and induce considerable lattice distortion.
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