[en] A simple, effective and rapid chemical procedure for separating ⁷²Ga from a mixed sample of soil has been developed, by using NaOH precipitation and isopropyl ether extraction. The chemical recovery is greater than 90%. The decontamination factors of fission products are greater than 10³, and the decontamination factor of soil matrix is 4.1 × 10³. The total time of the whole procedure is less than 50 min, then the method can meet the requirement of the detection of ⁷²Ga. (authors)

[en] A sequential separation method of U, Np and Pu from rock samples was established in this work. After digest the samples, Fe(OH)₃ coprecipitation and TBP extraction chromatography were used to remove the matrix elements and extracted U, Np and Pu. The U, Np and Pu fraction was separated by high performance liquid chromatography on a C18 reversed-phase column. A small amount of ²³⁷Np and ²³⁹Pu tracer was added to the non-radioactive rock samples, and dealt with the process, the chemical yield of Np and Pu were both better than 90%. The Uranium content of the sample was measured by MC-ICP-MS. the results are accordance with the ones determined by neutron activation method. (authors)

[en] Ultratrace amounts of long-lived radionuclides are critical nuclides for control of radioactive pollution, data measurement, geological disposal, and origin of the earth studies. The separation and measurement of these nuclides have become an important branch of radiochemistry, which attracts more and more attention in the industry. This paper systematically analyzes the progress on the research of pretreatment, radiochemical separation and purification, as well as the measurement methods. Meanwhile, some interesting technical problems are discussed. At last some suggestions and the key future research directions are given. (authors)

[en] In order to improve the accuracy of the fission yields of ¹⁵⁶Eu and ¹⁶¹Tb in neutron-induced uranium fission, radiochemical purity sample of ¹⁵⁶Eu and ¹⁶¹Tb has to be obtained. A separation procedure of Eu and Tb from uranium, aluminum and fission products was established in this paper. Aluminum was first removed by hydroxide co-precipitation method, then uranium was removed by calcium fluoride co-precipitation method, and rare earth elements were recovered by 30% TRPO-kerosene extraction method, Eu and Tb were separated from the mixed rare earth elements by cation exchange chromatography method. When the sample contains 2 g uranium, 0.65 g aluminum and fission products, the chemical recoveries of Eu and Tb are better than 80%, the decontamination factors are greater than 10⁶ for U, ²³⁹Np, ⁹⁵Zr, ¹⁰³Ru, ¹³¹I, ¹³²Te, ¹⁴⁰Ba, ¹⁴⁰La, ¹⁴¹Ce and ¹⁴⁷Nd. The method can meet the requirement of measurement of ¹⁵⁶Eu and ¹⁶¹Tb yield in neutron-induced uranium fission. (authors)

[en] ²³⁷Np is one of the key nuclides in non-α process of high level liquid waste because of long half-life and high biotoxicity. In this work,the effects of extractant concentration, initial nitric acid concentration and temperature were studied for Np (IV), Np (V), Np (VI) extraction process. The result shows that the increasement of concentration of N, N'-dimethyl-N, N'-dioctyl-3-oxa-glutaramide (DMDODGA) and initial nitric acid can enhance the distribution ratios of Np (IV), Np (V), Np (VI). When the concentration of DMDODGA is lower than 0.005 mol/L, 1 : 2-type complexe is found for Np (IV).When the concentration of DMDODGA is higher than 0.005 mol/ L, 1 : 3-type complexe is found for Np (IV). 1 : 2-type complexe is found for Np (V) and Np (VI), when the concentration of DMDODGA is in the range of 0.1-1.0 mol/L. The extractions between DMDODGA and Np (IV), Np (V), Np (VI) are exothermic reactions. The enthalpy changes are -59.55 kJ/mol, -22.02 kJ/ mol and -31.40 kJ/mol, respectively. The decrease of temperature is benefit for the reaction. (authors)

[en] In order to obtain the decay data of the short-lived nuclide ¹⁴⁴La, the ¹⁴⁴La samples with high abundance and high activity need to be prepared. In present paper, a separation method was established based on the twice delay separation method, in which the ¹⁴⁴Ba-¹⁴⁴La was separated in 15 s by HDEHP extraction with SISAK separation system, and the newly grown ¹⁴⁴La was separated by P204 extraction chromatographic column at 20 s. The effects of extraction time, concentration of extraction agent and medium condition on the extraction ratio were studied in detail, and the process of rapid radiochemical separation of ¹⁴⁴La from the fission products was established. The process takes about 50 s, and the chemical recovery rate of ¹⁴⁴La is about 75%. (authors)

[en] Magnesium oxide (MgO) nanostructures were synthesized by DC arc plasma jet chemical vapor deposition, which possesses the advantages of being simple, economical, fast, effective and environmentally benign. The formation of “tadpole”-, dendrite-, belt- and rod-like MgO nanostructures was confirmed by scanning electron microscopy and high-resolution transmission electron microscopy. Powder X-ray diffraction analysis revealed that the nanostructures consist of cubic phase MgO. Nanobelts that were 30–50 nm wide with a width/thickness ratio of 1–2 were synthesized in just 5 min. Most of the nanobelts were connected to others, and the connected nanobelts possessed a single-crystal structure. A formation mechanism for MgO nanostructures was proposed. Fourier transform infrared spectra indicated the adsorption of water and CO₂ on the MgO surface. The nanobelts exhibited relatively strong blue-green luminescence

[en] Condition monitoring and predicting of CNC machine tools are investigated in this paper. Considering the CNC machine tools are often small numbers of samples, a condition predicting method for CNC machine tools based on support vector machines (SVMs) is proposed, then one-step and multi-step condition prediction models are constructed. The support vector machines prediction models are used to predict the trends of working condition of a certain type of CNC worm wheel and gear grinding machine by applying sequence data of vibration signal, which is collected during machine processing. And the relationship between different eigenvalue in CNC vibration signal and machining quality is discussed. The test result shows that the trend of vibration signal Peak-to-peak value in surface normal direction is most relevant to the trend of surface roughness value. In trends prediction of working condition, support vector machine has higher prediction accuracy both in the short term ('One-step') and long term (multi-step) prediction compared to autoregressive (AR) model and the RBF neural network. Experimental results show that it is feasible to apply support vector machine to CNC machine tool condition prediction.

[en] In this work, a process of systematic separation for Pu and its fission products Pd, Ag, Cd, Sn, Sb and Zr was established. Firstly, these elements in the solution of hydrochloric acid medium were divided into five groups on strong basic anion resin. Then the target elements were separated and purified for each group. The method is simple, rapid and can separate the above 7 elements from the solution of one target. The separation method was verified by using irradiated uranium target. The results show that the chemical yields of the separation process are more than 70% for the 6 fission products, and the decontamination factors of the main interfering nuclides for the gamma spectrometry measurement are more than 1.0 × 10₃. The separation process can meet the requirements of chemical separation for fission yield measurement of valley nuclides from ²³⁹Pu fission. (authors)

[en] SiO₂-Fe₂O₃ heterogeneous metamaterial was fabricated by one-step self-assembly process. The micro-morphology and optical properties of the SiO₂-Fe₂O₃ heterogeneous metamaterials were characterized by scanning electron microscope (SEM) and UV/Vis/NIR spectrophotometer respectively. The crystal phase of the calcined Fe₂O₃ powders was characterized by X-ray diffraction (XRD). The influences of the concentration of SiO₂ suspension and voltage on heterogeneous metamaterials are discussed. The model of SiO₂-Fe₂O₃ heterogeneous photonic crystal was established, and the wavelength of the bandgap center was simulated and analyzed. The results show that the ordered SiO₂-Fe₂O₃ heterogeneous metamaterial can be successfully obtained by a one-step self-assembly process with no voltage when the concentration of SiO₂ suspension is 3% (in a short time). In the suspension system, the voltage is not beneficial to the self-assembly process, and even destroys the electrode cathode. As can be seen from transmission spectra, the as-prepared samples have three bandgaps, and the absorption peaks are obvious in the near infrared range (12351419 nm). In this paper, we show that the application of this composite system can avoid dependence on the ITO electrode material.