[en] High temperature anti-oxidation TiN/Ti_3Al intermetallic composite coatings were fabricated with the powder and AlN powder on Ti6Al4V titanium alloy surface by 6 kW transverse-flow CO_2 laser apparatus. The chemical composition, morphology and microstructure of the TiN/Ti_3Al composite coatings were characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). In order to evaluate the high temperature oxidation resistance of TiN/Ti_3Al coating, the isothermal oxidation test was performed in a high temperature resistance furnace at 600 °C and 800 °C, respectively. The result shows that the composite coating has a rapidly solidified fine microstructure consisting of TiN primary phase (granular-like, flake-like or dendrites), with an even distribution in Ti_3Al matrix. It indicates that a physical and chemical reaction between Ti powder and AlN powder has completely occurred under the laser irradiation condition. In addition, the microhardness of the TiN/Ti3Al intermetallic composite coating is 3.4 times higher than that of the Ti6Al4V alloy substrate and reaches 844 HV_0_._2. The high temperature oxidation behavior test reveals that the high temperature oxidation resistance of TiN/Ti_3Al composite coating is much better than that of titanium alloy substrate. The excellent high temperature oxidation resistance of TiN/Ti_3Al intermetallic composite coating is attributed to the formation of reinforced phases TiN, Al_2O_3 and TiO_2. The laser cladding TiN/Ti_3Al intermetallic composite coating is anticipated to be a promising high temperature oxidation resistance coating for Ti6Al4V alloy. - Highlights: • In-situ TiN/Ti_3Al composite coating was synthesized on Ti6Al4V alloy by laser cladding. • The influence of Ti and AlN molar ratio on the microstructure of the coating was studied. • The TiN/Ti_3Al intermetallic coating is mainly composed of α-Ti, TiN and Ti_3Al phases. • The relative oxidation resistance of the coating at 600 °C and 800 °C is 6.83 and 1.94. • The microhardness of the coating reaches 844HV_0_._2, 3.4 times higher than the bare substrate.

No abstract available

[en] Yibin Nuclear Fuel Element Plant (YFP) under the leadership of China National Nuclear Corporation is sole manufacturer in China to specialize in the production of fuel assemblies and associated core components for commercial PWR nuclear power plant. At the early of 1980's, it began to manufacture fuel assemblies and associated core components for the first core of QINSHAN 300 MW nuclear power plant designed and built by China itself. With the development of nuclear power industry in China and the demand for localization of nuclear fuel elements in the early 1990's, YFP cooperated with FRAMATOME France in technology transfer for design and manufacturing of AFA 2G fuel assembly and successfully supplied the qualified fuel assemblies for the reloads of two units of GUANGDONG Da Ya Bay 900 MW nuclear power plant (Da Ya Bay NPP), and has achieved the localization of fuel assemblies and nuclear power plants. Meanwhile, it supplied fuel assemblies and associated core components for the first core and further reloads of Pakistan CHASHMA 300 MW nuclear power plant which was designed and built by China, and now it is manufacturing AFA 2G fuel assemblies and associated core components for the first core of two units of NPQJVC 600 MW nuclear power plant. From 2001 on, YFP will be able to supply Da Ya Bay NPP with the third generation of fuel assembly-AFA 3G which is to realize a strategy to develop the fuel assembly being of long cycle reload and high burn-up

[en] The content of glycocholic acid (CG) in pregnant women's sera is detected with CG radioimmunoassay (RIA). The content of CG in sera of normal pregnant women after 32 weeks is ascended slightly with the increasing of pregnant month. It is less than 7.0 μmol/l before 31 weeks in pregnancy and less than 9.4 μmol/l after 32 weeks. The serum CG content of patients with intrahepatic cholestasis in pregnancy (ICP) is increased by 100%. The CG value of about half patients appears earlier than pruritus and ALT rise, the earliest CG increasing appears in the 20th pregnant week. It is the most sensitive method for ICP early diagnosis. 136 cases of ICP patients are observed and the results show that the higher the CG content, the higher the rate of intrauterine fetal anoxia; therefore, the dynamic observation of CG content in ICP patients is a dependable objective for surveillance fetal prognosis

[en] Background: In inertial confinement fusion (ICF) experiments, the temperature and density of fusion plasma zone are extremely important parameters requiring to diagnose. Purpose: The aim is to design a circuit for diagnosing the temperature information of the plasma zone. Methods: In order to diagnose the temperature information of plasma zone, neutron time-of-flight method was adopted to measure the neutron energy spectrum, i.e., to measure the delay time between the signal of the detector and start signal. We designed a program to accurately measure the time-of-flight with constant fraction discrimination (CFD) method, and used the TDC-GP21 (Time Digital Conversion) produced by ACAM Company (Germany) to complete accurate time measurement. Results: Based on the program, the electronics time-resolution of the measurement circuit within 1500 ns range is higher than 200 ps, and the measurement deviation is smaller than 0.06%. At the same time, the typical result of electronics time-resolution included detector time-resolution is 217.5 ps. Conclusion: The recording capability and measurement accuracy of the circuit designed can meet the needs of practical applications, which could be used in neutron diagnosing. (authors)

[en] Background: Histogram statistics method and average value method are widely used to obtain the baseline of nuclear signal processing. However, there still exist several shortcomings, such as low accuracy, weak real-time character and high hardware resource occupancy. Purpose: This study aims to improve the accuracy and the real-time performance of the baseline extraction for the digital nuclear instruments. Methods: A novel method of obtaining baseline is proposed, it is a real-time dynamic average method that can be easily implemented on a Field-Programmable Gate Array (FPGA) based multi-channel pulse height analyzer. By setting appropiate parameters, the accuracy and real-time character could be obviously improved. Results: This novel method not only occupies less hardware resource, but also achieves higher accuracy. The energy resolution of ¹³⁷Cs spectrum is got improved to 7.44%. Conclusion: This method can be applied to extract baseline of digital multi-channel pulse height analyzer with high accuracy and real-time response. (authors)

[en] This paper studies the energy resolution and time resolution of scintillation detector produced by SEN-LE Company with appropriate measuring method. The detector is composed by LYSO crystal (model MicroFC-30035-SMT), and the coupling size of SiPM optical-electrical converter is 3 × 3 × 10 mm. The measuring result of the detector is: the energy of ²²Na radioactive source is 511 keV, the energy resolution (FWHM) of 511 keV photon is 16%, and the time resolution is 135 ps. (authors)

[en] Nonlinear damage such as fatigue crack often occurs in some engineering structures, which brings challenges in structural damage diagnosis. A nonlinear damage diagnosis method based on ARMA/GARCH model is proposed to extract the nonlinear characteristic caused by cracks. First, the background description of ARMA/GARCH model is given and a damage diagnosis index based on this model is proposed to detect nonlinear damage location. The main advantage of ARMA/GARCH model is that this hybrid model can well simulate structural time domain acceleration response and effectively extract the nonlinear damage feature. An experiment of three-storey frame structure, which utilized a mechanism constituted of a bumper and a center column to model breathing crack, is studied. The results show that the damage diagnosis index based on ARMA/GARCH model exhibits good accuracy. (paper)

[en] Silicon anode is a promising candidate for the next generation electrodes for lithium ion batteries. However, the poor cycle performance of silicon caused by large volume expansion of silicon hinders the practical application of silicon anode. The large volume change results in the reformed solid electrolyte interface layer and the electrode/electrolyte interface is unstable. In this work, the native silica and N-doped carbon layer improve the stability of active particles/electrolyte interface and accommodate volume change so as to enhance the electrochemical performance of silicon-based anode material. The temperature has an effect on the growth of the oxide layer and electrochemical performance of electrode material. Superficial silica content on silicon particles increases as the temperature rises, and the cycle properties are improved as well. The sample presents the proper thickness of the silica layer and the composition of the carbon layer at 800 °C. Electrochemical tests show the sample delivers a capacity of 961.9 mAh g⁻¹ at 100 mA g⁻¹, with initial coulombic efficiency of 84.5%. Reversible specific capacity of 775.7 mAh g⁻¹ is obtained at 200 mA g⁻¹ after 50 cycles, with capacity retention of 86.1%. It also exhibits good cycling performance with a reversible capacity of 484.6 mAh g⁻¹ at 1 A g⁻¹ after 200 cycles. - Highlights: • Si-based material with silica and carbon coating layer is synthesized successfully. • The influence of temperature on property of material is investigated. • The silica and carbon layer improve the particle/electrolyte interface stability.

[en] The first principles calculations based on density functional theory are performed to investigate the stability, chemical bonding, elastic constants, hardness and Debye temperature of MB (M=V, Nb and Ta) compounds. The structures of these borides are optimized, and the lattice parameters are in good agreement with the experimental data. The calculated cohesive energy and formation enthalpy indicate that they are of a thermodynamically stable structure. The mechanical properties, including elastic constants C_i_j, bulk modulus, Young's modulus, shear modulus and Poisson's ratio, are calculated. The bulk moduli of them ranging from 263.0 to 278.4 GPa are larger than many common Laves phases and TaB with 278.4 GPa being the largest bulk modulus value among them. The population analysis is used to analyze the chemical bonds in these compounds. The hardness of the compounds is also evaluated, and the result reveals that TaB is the hardest compound among them. The Debye temperature of MB is calculated. The results show that the values of MB compounds range from 419.3 to 794.3K