[en] This article adopt content of natural radioactive nuclide in the soil of Jiaxing Region in Zhejiang Province examined during the bottom radiation investigation of the whole country, and the result of the bottom radiation investigation of the environmental radiation of Qinshan region, calculate out the environmental γ (X) radiation intensity distribution with energy, and using the energy response curve of thermoluminescent dosemeter that made with CaSO₄(Dy) and LiF(Mg, Cu, P) material, analyse its influence on environmental gamma dosage measurement. If we neglect the prevention of soil, air and the wrappings of TLD, the data examined with LiF(Mg, Cu, P) are lower by 35.48% in theory than the data examined with CaSO₄(Dy). The experimental result is given actually under the same condition according to two kinds of TLD, the former is lower by 10.74% than the latter, this indicate the influence obviously exists. (authors)

[en] The mechanical and tribological properties of tantalum and its alloy films are greatly influenced by their phase transformation. In this study, Ta and Ta-Ag films were prepared on carbon steel substrate by DC magnetron sputtering with various sputtering powers. The amorphous and nanocrystalline Ta and Ta-Ag film were produced at different sputtering powers from 40 to 110 W. The frictional properties of Ta and Ta-Ag films were investigated by rubbing against Si₃N₄ ball from RT to 700 °C. The nanocrystalline Ta-Ag films shows higher hardness values (12 GPa) compared with amorphous phase. The nanocrystalline Ta90-Ag8 film shows a low friction coefficient of about 0.20-0.30 when rubbing against Si₃N₄ ball at 700 °C. The segregation of Ag can effectively reduce friction coefficients of Ta-Ag film at 700 °C. The Ta-Ag films show high structure stability even after friction at 700 °C.

[en] The high-temperature properties of steel surface can be improved by molybdenum surface alloying. Molybdenzing was carried out on carbon steel in the multi-function double glow plasma surface alloying furnace. The friction and wear tests were conducted on a high temperature ball-on-disk tribometer under the temperature of 25 deg. C∼600 deg. C. The contents of alloy element varied with alloyed layer were detected by SEM attached with EDS. The molybdenized layer is composed of the deposited layer and diffused layer. The micro-hardness of alloyed layer decreases from HV650 on the top layer to HV240. The friction coefficient of molybdenized layer decreases from 0.5∼0.6 to 0.2∼0.3 and wear rate decreases by 20% at elevated temperature after molybdenizing.

[en] TiB₂ particles (5 vol% and 10 vol%) reinforced NiAl matrix composites were fabricated in-situ from Ti-B-Ni-Al system by arc melting. The reaction mechanism and mechanical properties of the composites were studied. When the reaction system was heated to 917 K, Ni and Al reacted with Ti to form the transient phase AlNi₂Ti, which continued to react with B to yield ultrafine TiB₂ particles acting as reinforcement agent. The apparent activation energy for these two reactions were calculated and found to be 497.99 kJ/mol and 2354.78 kJ/mol, respectively. The reinforcement agent exerted dispersion strengthening effect on the matrix. The room temperature compressive strength of the composites reinforced by 10 vol% of TiB₂ particles was determined to be 538.3 MPa, representing a 35.2% increase over NiAl alloy. To further refine the grain size, the rare earth element cerium (2 wt% and 4 wt%) was introduced to the composites. The compressive strength of the composites containing 4 wt% Ce was determined to be 571.1 MPa, representing a 43.5% increase over NiAl alloy.

[en] The laser system for the Fermilab-NIU photoinjector has been recently upgraded in order to improve reliability and to reduce amplitude fluctuations. Major modifications included the replacement of the oscillator by a diode-pumped passively mode locked Nd:YLF commercial laser. The oscillator delivers 5 ps long pulses at 81.25 MHz at an average power of 450 mW. The number of round trips in the multi-pass amplifier was reduced by half and image relaying was introduced throughout the optical system. The frequency of the IR (λ=1054 nm) pulse was quadrupled to UV (λ=263.5 nm) by two BBO crystals. The overall efficiency for frequency quadrupling was of order 20%. The shot to shot fluctuations in the UV are ∼5%. The UV energy on the cathode is 5 μJ/pulse (10 μJ/pulse without the pulse stacker), yielding charge of 10 nC/pulse

[en] A system and a method were developed for continuous production of glass-coated microwires with controllable glass thickness and metallic core diameter. Fe–Si–Al flakes were fabricated by planetary ball milling using ethanol as a dispersant. A composite noise suppression sheet was prepared with glass-coated microwires combined with Fe–Si–Al flakes. The characteristics of the conduction noise suppression of the composite sheet were evaluated on a microstrip line in gigahertz frequencies. The conduction electromagnetic noise was effectively suppressed by the composite sheet in broad-band frequency region; the power loss is greater than 70% in the frequency range from 0.7 to 8.5 GHz. - Highlights: ► System and method developed for producing glass-coated microwires. ► Noise suppression sheet prepared with microwires combined with Fe–Si–Al flakes. ► Power loss of noise suppression sheet greater than 70% for 0.7–8.5 GHz.

[en] Highlights: • The TiC and graphite-whiskers reinforced FeCoNiCu high entropy alloy composites can be prepared by FeCoNiCuTiC system. • Fe firstly reacted with Ti to form FeTi, then decomposed at high temperature, whereafter the Ti reacted with C to form TiC. • The apparent activation energy of the two steps $(\text{Fe}+\text{Ti}\to \text{FeTi},\text{Ti}+\text{C}\to \text{TiC})$ were 453.7 kJ/mol and 1139.3 kJ/mol. • The ultimate tensile strength and elongation of the composites were 566 MPa and 4.5% FeCoNiCu high entropy alloy matrix composites reinforced by in-situ TiC particles and graphite whiskers (5 vol% and 10 vol%, respectively), i.e., (TiC_p + C_w)/FeCoNiCu composites, were fabricated from FeCoNiCuTiC powder system using vacuum inductive melting method. The reaction mechanism of the mixed powder (Fe, Ti and C) and the mechanical properties of resulting (TiC_p + C_w)/FeCoNiCu composites were studied. It was found that two reactions ($\text{Fe}+\text{Ti}\to \text{FeTi}\text{and}\text{Ti}+\text{C}\to \text{TiC}$) occurred, when the powder system was heated to 1473 K. The apparent activation energy for these two reactions were calculated and found to be 25 kJ/mol and 2709 kJ/mol, respectively. The TiC particles (size, 3–5 μm) and graphite whiskers (diameter, 0.5–3 μm; length, 10–200 μm) were found to distribute uniformly throughout the high entropy alloy matrix. The crystal structure of FeCoNiCu matrix was FCC type. At room temperature, the maximum tensile strength of the composites was determined to be 566 MPa, representing a 57.7% increase over FeCoNiCu high entropy alloy matrix. Moreover, the elongation to failure of the new composites was determined to be 4.5%. The tensile fracture surface consisted of many fine dimples, suggesting a ductile nature in failure.

[en] Highlights: • A multilayered PEO/Ag/MoS₂ lubricating coating is deposited on Ti6Al4V alloy. • Ag interlayer benefits to improving wear resistance of PEO coatings at 350–600 °C. • PEO/Ag/MoS₂ coating exhibits low friction over a wide temperature range (RT-600 °C). • Ag₂MoO₄ glaze layer formed on Si₃N₄ ball provides lubrication at high temperature. To improve the tribological properties of titanium alloy at elevated temperatures, a multilayered lubricating coating was fabricated on the surface of Ti6Al4V alloy, involving an oxide ceramic coating deposited by PEO treatment, an electroplating Ag coating and a burnished MoS₂ film. The tribological properties were evaluated by a ball-on-disk high temperature tribometer over a wide temperature range (RT-600 °C). The results showed that the low friction coefficient and high wear resistance were exhibited at room and medium temperatures (2 and Ag layers and the high load supports provided by hard PEO coating. At high temperatures (> 350 °C), the oxidation of MoS₂ topcoats and the adhesive wear of softened Ag led to the direct contact of Si₃N₄/exposed oxide underlayer giving rise to the rapid increase of friction coefficient. As the temperature increased to 600 °C, the friction coefficient sharply decreased to a low level ~ 0.2, which was attributed to a combined effect of the diffused Ag from discharged reservoirs, the presence of high temperature lubricants (MoO_x, Ag₂MoO₄) and the formation of lubricants/lubricating glaze layers contact.

[en] Aluminum matrix composites reinforced with α-Al_2O_3, Al_3Ni and Al_3Ni_2 particulates were fabricated from Al and Ni_2O_3 powders by microwave synthesis. The reaction processes and resulting microstructures were analyzed by using differential scanning calorimetry, X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The results showed that the ignition temperatures of the reactions generated by microwave and conventional methods were approximately 695 °C and 735 °C, respectively. The time of microwave heating synthesis was about 8 min, which was much shorter than the time (more than 60 min) consumed by conventional heating method. It was found that the microstructure prepared by microwave heating was finer than that by conventional methods. The densities of the composites fabricated by microwave heating and conventional heating were 2.433 g/cm"3 and 2.622 g/cm"3, respectively. Some intermediate compounds were also observed in the final composites prepared by microwave heating synthesis. - Highlights: • The (α-Al_2O_3 + Al_3Ni + Al_3Ni_2)/Al can be fabricated by microwave heating synthesis. • The reaction ignition temperature is lower than that in the conventional heating. • The microstructures are finer than that by conventional heating method. • The fabrication time is much shorter than that by conventional heating method. • Some intermediate compounds can be remained in the final composites

[en] The effects of carbon additions on reaction mechanisms and mechanical properties of Al-based composites fabricated in-situ through Al–SiO_2 system were studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray energy dispersive spectroscopy (EDS). It was found that when the powder of C was added into the Al–SiO_2 system, Al first reacted with SiO_2 to form the α-Al_2O_3 and Si. Some of the Si then reacted with the C to form the SiC, and the remaining Si dissolved into Al to form the Al–Si alloy. Based on the DSC curves obtained from five different heating rates, the apparent activation energy for the synthesis of the new composites was calculated and found to be 309 kJ/mol, which was larger than that of Al–SiO_2 system that yielded the same reinforcement volume fraction of 30%. As compared with the reference materials prepared from the Al–SiO_2 system, the morphology of Si in the new composites changed from a large block to a needle-like shape. Moreover, the tensile strength and ductility of the new materials increased from 165 MPa and 3.95% to 208 MPa and 4.20%, respectively