Narrow Results

Based on the working principle of the signal detection and servo feedback control of the electrostatic accelerometer, in this paper, the main electronic noise components affecting the measurements of the accelerometer are analyzed and the corresponding expressions are determined. The resolution of the designed electrostatic accelerometer is lower than 10${}^{-9}$m/s²/Hz${}^{1/2}$, which cannot be verified directly due to limitations imposed by the vibration of the ground environment. However, it can be evaluated indirectly by the testing of electronic noise under open-loop conditions. Through this process, the resolution of 3× 10${}^{-9}$m/s²/Hz${}^{1/2}$ of the Taiji-1 inertial sensor was verified and found to be in agreement with results obtained in orbit.

In our new approach, evaporation residue cross-sections for new superheavy nuclei with atomic numbers $Z=114-118$ are estimated by calculation of vital characteristics of superheavy nuclei synthesis such as the fission barrier height, the compound nucleus formation probability and the survival probability of the residue nuclei. Our presented estimation is in good agreement with available experimental data. In addition, this new approach allowed us to predict the evaporation residue cross-sections for superheavy nuclei with $Z=119$ and 120 via introducing synthesis box and compare our results with other models. It is shown that the fission barrier heights of two nuclei with $Z=119$ and 120 are comparable with their corresponding neutron separation energies. It is suggested that for the synthesis of new superheavy nuclei, it is proper to use nearly double magic nuclei such as ${}^{50}\mathrm{\text{Ti}}$ as our projectile, so that the fission barrier heights remain high.

In this paper, we applied the method developed by Santhosh and Safoora in [Phys. Rev. C  94 (2016) 024623; 95 (2017) 064611] to theoretically investigate the fusion, evaporation-residue (ER) and fission cross-sections of the synthesis of the unknown superheavy ${}^{309,312}$126 nuclei produced by using the ${}^{58}$Ni + ${}^{251}$Cf and ${}^{64}$Zn + ${}^{248}$Cm combinations. The charge asymmetry, mass asymmetry and fissility of the DiNuclear System (DNS) in the synthesis of the mentioned combinations are also estimated. The calculated results show that the ER cross-sections for the synthesis of the ${}^{309-317}$126 nuclei are predicted to be much less than 1.0fb. In particular, it has been found that there may exist a valley of the ER cross-sections in the synthesis of a superheavy $Z=126$ element, which produces the ${}^{313}$126 isotope. Subsequently, a model for the mass dependence of the ER cross-section in the synthesis of the ${}^{307-320}$126 isotopes has been proposed for the first time. On the other hand, the quasi-fission process strongly dominates over the fusion in the two concerned interacting systems. The present results, together with those reported in the previous studies, indicate that the investigated projectile–target combinations are not capable for the synthesis of the ${}^{309,312}$126 isotopes due to tiny fusion cross-sections (about 2–3zb), which go beyond the limitations of available facilities. Further studies are thus recommended to search for alternative interacting systems. In conclusion, this work provides useful information for the synthesis of the gap isotopes ${}^{308-317}$126, which have not been well studied up to date.

Ultra fine metallic powders have an increasing application in magnetic materials, catalysts and chemical and metallic industries. In this research, magnesium-thermic reduction in gas phase was used to synthesize an ultra-fine nickel-iron intermetallic compound. Synthesis of nickel-iron submicron powder by metal chlorides and magnesium vapors was studied. Evaporation rate of the chlorides and magnesium in the range of 800 to 920 degrees Celsius was measured in order to control the composition of the resulting compound. The simultaneous reduction of the chlorides was done in a tubular furnace under argon atmosphere at 920 degrees Celsius. Chemical analysis of the resulting compound and the X ray diffraction analysis identified the formation of Ni₃Fe compound. The particle size of the compound was measured 60 to 230 nano-meters by scanning electron microscopy. In addition, the particles were spherical and homogeneous. The product may be used for production of magnetic and catalytic applications.

Titanium diboride (TiB₂) has attracted great interests for its excellent mechanical properties, chemical resistance and good thermal and electrical conductivities. So it is widely applied as cutting tool composites, wear resistant parts, metal melting crucibles and electrode materials. This paper presents synthesis of nano titanium diboride powders via sol-gel method using a mixture of TTIP and B₄C as precursors. In the hydrolysis step, B₄C to TTIP molar ratio varied from 1.3 to 2.5. Solution samples stirred well and after aging and drying process, they were heat treated in an argon atmosphere. X-ray diffraction (XRD) patterns and Scanning electron microscopy (SEM) analysis showed that the percentage of synthesized TiB₂ increased gradually as the molar ratio of B₄C to TTIP reached to 2.3, afterward increasing the B₄C to TTIP molar ratio caused decreasing of titanium diboride percentage.

Innovating dosimetric materials, which includes design and development of new dosimetric materials based on rare earth oxides, is challenging. Yttrium oxide (Y${}_{\mathrm{\text{2}}}$O${}_{\mathrm{\text{3}}})$ is one of the most important sesquioxides and presents crystal characteristics that enable doping with rare earth ions, making it a promising material for radiation dosimetry. This paper reports on the development and measurement of Electron Paramagnetic Resonance (EPR) signal response for Y${}_{\mathrm{\text{1.98}}}$Eu${}_{\mathrm{\text{0.02}}}$O${}_{\mathrm{\text{3}}}$micro rods that have undergone facile low-pressure hydrothermal synthesis and bio-prototyping. As- synthesized powders with narrow sub-micrometer particle size distribution with d${}_{\mathrm{\text{50}}}$ of 584 nm exhibited a reactive surface, which led to the formation of stable aqueous suspensions by controlling the surface charge density of particles through alkaline pH adjustment. Ceramic samples with dense microstructure were formed by sintering at 1600 ${}^{\text{o}}$C for 4h at ambient atmosphere. Y${}_{\mathrm{\text{1.98}}}$Eu${}_{\mathrm{\text{0.02}}}$O${}_{\mathrm{\text{3}}}$micro rods were irradiated using a ${}^{\mathrm{\text{60}}}$Co source with doses from 1 to 100 kGy, and EPR spectra were measured at room temperature in X-band microwave frequencies. Sintered samples exhibited linearity of the main EPR signal response from 10 Gy to 10 kGy. Supralinearity was observed for higher doses, which is possibly ascribed to formation of more defects. Using europium as a dopant enhanced the EPR signal of yttrium rods remarkably, due to 4f–4f transitions of the Eu${}^{\mathrm{\text{3+}}}$ ion. These innovative findings make europium-doped yttrium oxide a promising material for radiation dosimetry.