[en] MoS₂ particles of uniform size (ca. 70 nm) consisting of random and loosely stacked layers have been synthesized from hydrazine solution with (NH₄)₂Mo₃S₁₃ as the precursor at 180 deg. C for 16 h under hydrothermal conditions. The particles were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HREM). The influences of reaction conditions are discussed while a mechanism is proposed to explain the formation of this peculiar morphology

[en] The theoretical π-nucleus optical potential is constructed based on the α-particle model of the nucleus. This potential has only two necessary inputs, namely, the α-particle wave function of the nucleus and the π-α amplitudes, and has otherwise no adjustable parameters. The differential cross sections for π-¹²C elastic scattering are calculated using this potential over a wide energy region (260-50 MeV). The calculated results show better agreement with the experimental data, particularly in the low-energy region, than those calculated with the Kisslinger potential. (orig.)

[en] Pusblished in summary form only

[en] Coupling La-doped BaF₂ crystal to phototube is an effective way to prevent signal pileup in ultra-fast radiation detector under strong γ field. The ratios of slow components to fast ones of domestic BaF₂ crystal and La-doped BaF₂ crystal have been investigated through Synchrotron Radiation Decay Time Spectroscopy and X-ray Excited Emission Spectroscopy. The mechanism of the slow component suppression by doping with La and the anti-irradiation property of BaF₂ (La) are studied. The slow component suppression of ultra-fast radiation detector, which was composed of BaF₂(La) and GD40Z phototube is measured through Synchrotron Radiation

[en] The authors study the relationship between the levels of serum TGF-α and LN in gastrointestinal malignant tumor and the tumor formation and metastasis. Adopting radioimmunoassay measured serum TGF-α and LN levels in 40 cases of carcinoma of stomach, 24 cases of carcinoma of esophagus and 32 cases of liver cancer. The level of serum TGF-α in the patients with the three kinds of tumors was significantly higher than that of the normal control group (P < 0.05, P < 0.01); except for the group of carcinoma of esophagus, the level of LN was significantly higher than that of the normal control group (P < 0.05, P < 0.01). Meanwhile, the two markers of the metastasis group were significantly higher than that of the group without metastasis (P < 0.05). Elevation of the level of serum TGF-α and LN is closely related to the invasion and metastasis of the three kinds of malignant tumors, and is valuable for tumor diagnosis and prognosis evaluation

[en] Highlights: • We propose a SCWR fuel assembly with two-row fuel rods between the hexagonal moderator channels. • The new concept can resolve the contradiction between uniform and sufficient moderation. • Structural size and thermal–hydraulic performance are taken account of in the fuel assembly. • Larger infinite multiplication factor and smaller local power peaking factor could be obtained. • Two two-row hexagonal fuel assembly concepts are proposed for the engineering application. - Abstract: A new hexagonal fuel assembly (FA) design which has two rows of fuel rods between the hexagonal moderator channels is proposed for the thermal supercritical water cooled reactor (SCWR). The new concept is well considered for the performance of uniform moderation and sufficient moderation, and with respect to structural size and thermal–hydraulic performance. The neutron physical performance of the two-row hexagonal FA with acceptable configuration is discussed. The results show clearly that a better balance between uniform moderation and sufficient moderation can be obtained in the two-row hexagonal fuel assembly

[en] The high voltage power supply of the low hybrid heating system for the HL-2A tokamak includes numerous energy storage elements and non-linear elements. Its output voltage will decline to a certain extent as the load of the klystrons is connected to it, and in the course of the HL-2A tokamak discharge, the output voltage will also change while the output voltage of the preceding power supply of the 125 MVA M-G set change. In order to resolve the problem, simulation using MATLAB is carried out. A strategy of PID feedback control and feed-forward compensation is used. Design and parameters choice of the PID controller are analyzed in detail. The experiment results show that this strategy designed according to the simulation can meet the requirements of the voltage stability of the power supply very well. (authors)

[en] Numerical analyses were carried out to investigate the response of a sandwich beam with a negative stiffness (NS) core under quasistatic compression and low-velocity impact at the center. By varying the thicknesses of face sheets and interlayers and the lengths of segments, a parametric study on the impact resistance of the sandwich beam is conducted. The maximal deflection of the top face sheet and the strain energy stored in the NS beam were recorded at the moment when the impactor’s velocity decreased to zero. Based on the impact simulation, a multi-objective optimization problem on the beam configuration was set up to find out the most efficient antideformation design at the impact velocity of 2500 mm/s. To solve the problem with the surrogate model method, an optimal Latin hypercube sampling (OLHS) technique and a two-phase differential evolution (ToPDE) algorithm were utilized to generate calculation points in the design space, respectively. Then different surrogate models including the RSM model, the Kriging model and the RBF model, were compared to give the best approximation of the original problem. In the end, the genetic algorithm (GA) dealing with discrete optimization problems was employed to obtain the optimum solutions. Results indicate that different parts of the NS beam dominate the resistance to deformation under different levels of impact intensity. The largest portion of the strain energy is stored in the four curved plates. In the obtained optimization solution, the longest segment is near the two ends and the flat plates near the top are thicker, which is instructive to the beam design on improving impact resistance.

[en] The conceptual design and simulation of HL-2A resonant magnet perturbation (RMP) coils power supply are introduced, including its power supply topology, the selection of basic units and its control modes. The RMP coils will be energized by DC power supply with the amplitude up to 4 kA, or AC power supply with maximum amplitude up to 4 kA with adjustable frequency up to 1 kHz. Though choosing the sound power supply topology and its control modes, the RMP coils power supply can meet the requirements of both fast response and low current ripple to satisfy the ELM control and minimize adverse effects on plasma control as far as possible. (authors)

[en] Nanocrystalline lead chalcogenides PbE (E=S, Se, Te) were synthesized conveniently by the reaction of Pb(CH₃COO)₂·3H₂O and elemental chalcogens in ethylenediamine (en) under ultrasonic irradiation. XRD and TEM techniques were employed to characterize the products. The solubility of chalcogen in en was found to be the key factor of the reaction. A three-step mechanism was proposed to account for the formation of the products