[en] The average magnetization of the lattice points in the hybrid spin Blume-Capel model in the double-mode random interlaced crystal field on nanotubes was studied by using the effective field theory, and the relationships between the average magnetization of the system lattice points and the value probability of the double-mode random crystal field, the external magnetic field, the crystal field parameters and the ratio of the strength of the crystal field were obtained. The results show that the magnetization of the system is more abundant than that of the Blume-Capel model under the action of constant crystal field due to the competition of many factors such as the value probability, external magnetic field, exchange interaction, the ratio of crystal field strength and the strength of crystal field. The average magnetization of the system will be inhibited by the double-mode random cross-crystal field, and the saturation value of the ground state will be less than 5/6. The external magnetic field causes the second order phase transition of the system to disappear. Under certain conditions, the system has a first order phase transition. The mean magnetization of the system showed partial missing and negative values. (authors)

[en] In this paper, we study forming limit diagram (FLD) of high strength steel (HSS) under high temperature condition to simulate the hot stamping process. We investigate the sheet specimen temperature distribution in hot FLD test. First, we propose a simple model of heat transfer process in sheet specimen, in which the sheet specimen is separated into two sections due to different mechanism. In thermal radiation, the convection and thermal contact conductance are included in two partial differential equations (PDEs) to express the temperature distribution in these two sections (S_1 and S_2 sections). Second, hot FLD experiments (Nakazima test) are performed and temperature distributions of sheet specimen are investigated by thermal infrared imager. Furthermore, the experimental temperature distributions are compared with theoretical ones, and these two measurements make good agreement between each other. This conclusion validates the feasibility of proposed thermal model in hot stamping process. In addition, an uneven sheet temperature distribution is examined in expansion process experiment, we observe that the temperature of specimen increases from center to edge until it reaches the temperature of punch. The further theoretical analysis proves that this phenomenon is mainly caused by the punch through thermal contact conductance between punch and S_1 section, which indicates that a hot punch is indispensable to sustain the temperature of the deforming sheet. Third, the theoretical temperature distribution on S_1 section under different die height is calculated. The radiation heat flux of the sheet decreases as the die height is increasing, but the sheet temperature increment is small, which implies that the height of die affects the sheet temperature slightly. - Graphical abstract: Two PDEs are proposed to represent the sheet temperature distribution in the hot FLD test process with the heat transfer considered, such as convection, conductance and radiation heat transfer. The test about sheet temperature distribution in hot FLD test is carried out, the experimental data is compared with the theoretical one. The heat flux of different areas of the sheet is calculated and the result proves that the contact heat flux between sheet and punch is the major factor to affectthe sheet temperature distribution. Meanwhile, the temperature distribution of the area which contacts with the punch is calculated by using the die height as a parameter, the results represent that the die height affectsthe sheet temperature slightly. - Highlights: • An uneven sheet temperature distribution is found in hot FLD test. • The theoretical way is proposed to analyze the sheet temperature distribution. • The theoretical data agree well with the experimental data. • The thermal conductance is proved as a major factor affecting sheet temperature. • The die height affects the sheet temperature distribution slightly.

[en] Graphical abstract: - Highlights: • Cd_0.65Zn_0.35S-TiO₂ nanotube is fabricated by a hydrothermal sulfuration method. • The hydrothermal temperature affects the composite's crystallinity and morphology. • Hydrothermal treated sample at 120 °C shows superior H₂ evolution activity. • Enhanced activity is due to the increased crystallinity and 1-D tubular structure. - Abstract: Titania nanotube-Cd_0.65Zn_0.35S nanocomposite (Cd_0.65Zn_0.35S-TiO₂) was synthesized from titanate nanotubes for ion change of Cd²⁺ and Zn²⁺ followed by hydrothermal sulfuration treatment using thiourea as sulfur source. The Cd_0.65Zn_0.35S-TiO₂ with enhanced crystallinity of TiO₂ nanotube can be obtained by increasing hydrothermal temperature from 90 °C to 120 °C. And further increasing hydrothermal temperature to 150 °C, TiO₂ nanotubes collapse and transform into irregular shaped particles. The photocatalytic activity for hydrogen production of the prepared Cd_0.65Zn_0.35S-TiO₂ with different hydrothermal temperature was investigated under visible-light irradiation. The result shows that the Cd_0.65Zn_0.35S-TiO₂ with hydrothermal temperature of 120 °C presents the highest hydrogen evolution rate and photostability, which can be attributed to a rapid charge transfer at the interface between Cd_0.65Zn_0.35S and TiO₂ nanotube due to the increased crystallinity and unique 1-D nanotubular structure of TiO₂

[en] The residue of spent fuel assembly after shearing and leaching in the reprocessing plant is called Leached Hull. The measurement of the U and Pu content will be an important reference for judging the level of spent fuel dissolution process, or as a judgment standard for whether it is necessary to re-dissolve the Leached Hull. In this paper, based on the analysis of the radioactive composition of the Leached Hull, and in view of the difficulty in analyzing the quality of U and Pu in the Leached Hull by directly by measuring the U and Pu characteristic particles, a method of indirectly measuring the residual U and Pu content in the Leached Hull is proposed, and the preliminary research work is carried out. In this method, a measuring device based on ³He proportional counter is designed. The content of ²⁴⁴Cm in the Leached Hull is measured and analyzed by neutron coincidence method. Aiming at the possibility of inhomogeneous distribution of radioactivity in the measured object, the simulation calculation of spatial detection efficiency distribution in the measuring device is carried out, and the limit error analysis of measurement is given. The nuclide composition information simulator of spent fuel assembly is established in the calculation program, the concerned nuclide content of the same type of spent fuel assembly in Japan is analyzed and calculated, then compared with the destructive analysis(DA)analysis result of this assembly, the uncertainty of the calculation result is given, and the ²⁴⁴Cm/U (Pu) value in the spent fuel assembly corresponding to the Leached Hull is calculated by the above program. Combined with the measured data and calculated data, the mass of U and Pu in the Leached Hull can be deduced. In addition, this paper also analyzes the error composition of this measurement analysis method, evaluates the uncertainty of the final analysis results to meet the needs of process judgment, and points out the direction of the next research work. (authors)

[en] Based on higher-order asymptotic stress fields for the interfacial crack between homogeneous material and functionally graded materials (FGMs), stress intensity factors were calculated by finite element and node collocation methods. The method was verified by comparing the results with numerical solutions obtained in other studies, with varying degrees of homogeneity. The comparison showed that the obtained results agree well with the numerical solutions

[en] Apatite-type lanthanum silicate was successfully synthesized via a solid state reaction protocol at 1400 °C in a vacuum for 4 hours. The powder was synthesized faster and at a lower reaction temperature than by conventional solid state reaction methods. The resulting powder was used in the fabrication of a coating deposited by atmospheric plasma spray (APS) technology. The microstructure of the coating was analyzed by X-ray diffraction and scanning electron microscopy. Heat treatment was found to fully crystallize the coating, increasing its density. The ionic conductivity of the apatite coating was 0.39 (0.054) mS/cm at 850 (700) °C, and its activation energy was 0.67 eV

[en] A tungsten (W) coating (∼900 μm) was deposited on a copper (Cu) substrate via the atmospheric plasma spray (APS) technique, and then annealed in vacuum. Measurements of microstructure, density, oxygen content, microhardness and thermal conductivity show that an appropriate thermal annealing treatment can dramatically improve the quality of the coating. The oxygen content was found to drop from 0.48 wt.% before annealing to 0.06 wt.% after; microhardness increased by about 50%; and thermal conductivity nearly doubled. These results indicate that a vacuum-annealed APS-W coating can match or even surpass the quality of W coatings deposited by vacuum plasma spray (VPS). Compared with VPS, annealed APS is a more convenient and cheaper method to obtain W coatings suitable for fusion applications.

[en] CdS nanoparticles were confined within titanate nanotubes (TNTs) by an ion-exchange reaction and a subsequent sulfurization process. Prior to the ion-exchange reaction, the exterior surfaces of the TNTs were modified by a silane coupling agent to make CdS nanoparticles selectively deposit on the inner wall. The composites were characterized by high-resolution transmission electron microscopy, powder x-ray diffraction, inductively coupled plasma atomic emission spectrometry, N₂ adsorption–desorption and UV–vis absorption spectra. The results confirm that CdS in the range of 2–3 nm in diameter are confined within the inner cavity of the TNTs. CdS confined within TNTs shows a significant blue-shift of the absorption band edge compared with CdS nanoparticles deposited on the exterior surface of TNTs. Also the TNTs-confined CdS composite exhibits enhanced photocatalytic activity and photostability for hydrogen evolution under visible light illumination due to the quantum size effect of CdS as a result of the spatial confinement effect of the TNTs. (paper)

[en] With the energy crisis and resource depletion nowadays, novel, highly performing, and cost-effective semiconductors are in urgent demand for efficiently harvesting solar energy for photoelectrochemical applications. Herein, this study presents low-cost anatase TiO₂ hollow nanoparticles as prepared by a critical liquid-phase deposition (LPD) processing combined with a hydrothermal reaction and calcination processing, without involving any templates. The additional LPD processing not only makes the resulting samples more visible light responsive, but also results in hollowing the TiO₂ nanoparticles (nanosheets vs. hollow nanoparticles). Importantly, commercial TiO₂ powder is employed as the starting material to achieve the final synthesis of TiO₂ hollow nanoparticles, making it scalable and cost-effective for production and applications. As a by-product, the fluoride, formed during the preparation process, is assumed to play a significant role in hollowing through chemically induced self-transformation and Ostwald ripening, in addition to enhancing the crystallinity. The beneficial structural evolution to the hollow nanoparticles enables the improvement of the photoelectrochemical performance through impressive inhibition of the recombination of the photoelectrons and holes, which is well evidenced by I_ph and EIS (Nyquist plot), as well as by I–V curve and electron lifetime evaluations as for the assembled DSSCs with the prepared TiO₂ hollow nanoparticles under simulated sunlight illumination (50 mW/cm²).

[en] A composite structure, TiO₂ nanotube array/CdSe nanoparticle/TiO₂ layer, was fabricated by inserting CdSe nanoparticles into anodized TiO₂ nanotube arrays via ultrasonic-assisted cyclic voltammetry electrochemical deposition and subsequently wrapped by a TiO₂ thin layer via TiCl₄ hydrolysis. The films were characterized by X-ray diffraction, field emission scanning electron microscopy, energy dispersive spectroscopy and UV–vis diffuse reflectance spectroscopy. For the film used as the photoanode, linear sweep voltammetry and transient photocurrent were investigated in a three-electrode system under visible light illumination. And the photocatalytic activity was evaluated by the oxidation of glucose in the supporting electrolyte at different potential bias under visible light illumination. The results showed that CdSe nanoparticles are prone to disperse into the nanotube arrays via cyclic voltammetry electrochemical deposition under ultrasonic condition. Increasing cyclic voltammetry cycle increases the loading of CdSe on the TiO₂ nanotube arrays. The CdSe-sensitized TiO₂ nanotube array films exhibit a wide-absorption response in the visible light region. The TiO₂ nanotube array/CdSe/TiO₂ film, prepared by ultrasonic-assisted electrochemical deposition with 50 cyclic voltammetry cycles and subsequently coating a TiO₂ thin layer, exhibits better protection against photocorrosion of CdSe. The TiO₂NTA/CdSe/TiO₂ film possesses visible light photoelectrocatalytic activity on the degradation of glucose. - Highlights: ► CdSe is electrochemically deposited onto TiO₂ nanotube arrays with ultrasonics. ► TiO₂ thin layer overcoating on the arrays can protect CdSe from photocorrosion. ► TiO₂ nanotube array/CdSe/TiO₂ film possesses visible light photocatalytic activity.