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[en] Highlights: • A thick TU1/316 L clad plate was constructed for nuclear fusion equipment. • Technical parameters of explosive welding were obtained and optimized by numerical calculations. • An efficient procedure was developed for explosion bonded TU1/316 L bimetallic plates. - Abstract: TU1/316 l clad plates with a high thickness are used in nuclear fusion equipment as coil terminals. The technical specifications of clad plates for nuclear fusion equipment, such as the composite ratio, tensile strength, shear strength and scale of the interfacial wave, are significantly higher than those of clad plates for conventional applications. It is difficult to produce high-quality clad plates through explosive welding experiments alone. To manufacture high-quality TU1/316 L clad plates, the technical parameters of the explosive welding process were obtained and optimized by theoretical analysis and numerical calculations. A procedure for fabricating explosion bonded TU1/316 L clad plates was successfully determined through the combination of numerical calculations and experiments, and the bimetallic plates were used to manufacture international thermonuclear experimental reactor (ITER) components.
[en] The multi-walled carbon nanotubes (MWCNTs) /ferriferous oxide (Fe3O4) nano-composites have important research value in electromagnetic wave absorbing. Firstly, MWCNTs and nano-Fe3O4 particles were ball-milled by a ball mill to obtain Fe3O4/MWCNTs nanocomposites. The Fe3O4/MWCNTs nanocomposites were characterized by XRD, TEM and network vector analyzer. Finally, a model of microwave attenuation mechanism for Fe3O4/MWCNTs nanocomposites was established. The reflectivity of Fe3O4/MWCNTs nanocomposites was calculated and compared with the transmission model of electromagnetic wave incident vertically into Fe3O4/MWCNTs powder in free space random dispersion space. The results of the two models are almost identical, which provide a reference for predicting the microwave absorbing properties of Fe3O4/MWCNTs nanocomposites. (paper)
[en] In order to build a set of test methods for quantified and efficient evaluation of the detonation properties of commercial explosives, three pressure-conducted types of novel velocity probes have been developed. The LS-DYNA program is used to estimate the conduction pressure and an underwater explosion test is performed to demonstrate the ability of recording the continuous travel trajectory of detonation and shock wave, which indicates that the threaded wire with metal foil (TW/MF) probe shows the most satisfactory performance. Using this probe, various test methods are built to determine the detonation properties of commercial explosives, i.e. detonation velocity, critical diameter and thickness, sympathetic detonation and C–J pressure. The results show that continuous measuring systems based on the TW/MF velocity probe can be successfully applied in the evaluation of the performances of commercial explosives, which is superior to the conventional approaches in measurement accuracy, convenience, uniformity and quantification. (paper)
[en] Gaseous detonation is a new method of heating the precursor of nanomaterials into gas, and integrating it with combustible gas as mixture to be detonated for the synthesis of nanomaterials. In this paper, the mixed gas of oxygen and hydrogen is used as the source for detonation, to synthesize nano TiO_2, nano SiO_2 and nano SnO_2 through gaseous detonation method, characterization and analysis of the products, it was found that the products from gaseous detonation method were of high purity, good dispersion, smaller particle size and even distribution. It also shows that for the synthesis of nano-oxides, gaseous detonation is universal. (paper)
[en] This study proposed a new method for coating tungsten–copper alloy to copper surface. First, the tungsten–copper alloy powder was pre-compacted to the copper surface. Then, the powder in the hydrogen atmosphere was sintered, and the pre-compacted powder was compacted by explosive compact-coating. Finally, diffusion sintering was conducted to improve the density of the coating layer. The theoretical density of the coating reached 99.3%. Microstructure characteristics indicated that tungsten and copper powders were well mixed. Tungsten particles were larger than copper particles. Scanning electron microscope (SEM) fracture surface analysis was different from the traditional fracture of metals. Coating and substrate joint surfaces, which were analyzed by SEM, indicated that the tungsten–copper alloy was sintered on the copper surface. The hardness of the coating layer was 197.6–245.2 HV, and the hardness of the substrate was approximately 55 HV. (paper)
[en] Utilizing titanyl sulfate as a TiO2 source, via a novel synthesis method-the detonation method-nanosized TiO2(n-TiO2) powders were prepared. The results showed that the as-prepared n-TiO2 powders did not have enough time to grow into large and fine crystallites, and that the characteristics of high temperature, high pressure and high cooling were helpful in the synthesis of nanosized materials. The anatase phase appeared to be the stable form of nanocrystalline TiO2 at small crystallite sizes to some extent and part of the rutile phase could transform to the anatase phase when the detonation products were oxidized to eliminate the impurities via the combined action of chromic anhydride (CrO3) and concentrated nitric acid. The main reason resulting in the reversal of stability of anatase and rutile could be the differences in the surface energy of anatase and rutile at small crystallite sizes
[en] TiO2 photocatalyst is prepared via the gaseous detonation method. The structure and properties of the samples are investigated by using x-ray diffractometer, transmission electron microscope, UV–vis spectroscopy, and Infrared spectroscopy, and the photocatalytic performance of the products is measured by methyl orange solution removal experiments under UV irradiation. Results indicate that the initial concentration of TiCl4 exerts a significant impact on the particle size of the resultant samples. The average particle size of the samples decreases significantly as the TiCl4 concentration decreases. When the TiCl4 initial concentration is 2.09 mol m−3, the prepared sample shows the highest photocatalytic activity, an average particle size of 18.8 nm, and anatase content of 87%. Furthermore, the band gap of the sample is 3.18 eV, and its rate constant k is 0.1 min−1. Photocatalytic activity of this sample is much higher than other products obtained in this work and slightly lower than commercial P25. (paper)
[en] Carbon-encapsulated Fe–Ni alloy nanoparticles were synthesized through detonation using two composite explosive precursors doped with Fe (NO3)3 · 9H2O and Ni(NO3)2 · 6H2O · The morphology, components, and magnetism of the synthesized carbon-encapsulated alloy nanoparticles were characterized through x-ray diffraction studies (XRD, Rigaku, D/Max 2400, Japan), Raman spectroscopy (Raman, Thermo Fisher, DXR Microscope, USA), Transmission electron microscopy (TEM, FEI, Technai F30, USA) attached with energy dispersive x-ray spectroscopy (EDS), and vibrating sample magnetometer (VSM, JDM-13, China) analyses. The denotation products of the two precursors were compared. The influence of the components of the two precursors on the products was also analyzed. Results showed that both precursors detonated and synthesized the carbon-encapsulated Fe–Ni nanoparticles with a core–shell structure. The grains exhibited sizes ranging from 10 nm to 100 nm and were uniformly distributed. The encapsulated metal core was mainly composed of different proportions of Fe and Ni. The outer shell was composed of graphite and amorphous carbon. VSM analysis indicated that the detonated composite nanoparticles showed superparamagnetism at room temperature. (paper)
[en] The quenching-resistant solid-state fluorescent polymer carbon dots (SSFPCDs) were rapidly prepared by a one-step gaseous detonation approach within milliseconds using citric acid (CA) and urea as the precursors, which exhibited bright blue solid-state fluorescence with an excitation/emission maximum at 360/442 nm and an excellent film-forming ability by simple heat-treatment without additional curing agent. Moreover, SSFPCDs were employed to fabricate white light-emitting diodes (WLEDs) with a color coordinate of (0.31, 0.42) and a color temperature of 6249 K. This work not only provided a rapid pathway for preparation of SSFPCDs, but also achieved low-cost and environment-friendly SSFPCDs-based WLEDs. (paper)
[en] Carbon-coated copper (Cu-C) nanoparticles with a core–shell structure were prepared by detonation decomposition of energetic Cu ion doped sol–gel explosive precursors. The composite nanoparticles were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), high resolution TEM, energy dispersive X-ray spectroscopy, and Raman spectroscopy, respectively. The results indicate that the as-obtained core–shell structure Cu-C nanoparticles are with diameter about 10–40 nm. The composite nanoparticles are composed of face-centered cubic-Cu and the amorphous/graphitic carbon coating shells. The thermal stability of the obtained samples was studied by a difference scanning calorimetry–thermogravimetric analyzer. By varying the composition of initial mixtures that contain Cu ion explosive precursors, the different size and chemical composition of composite nanoparticles are shown in this study. The growth mechanism of Cu-C was also briefly discussed.