[en] An ultrasonic wave cerium (IV) decontamination technology for stainless steel wastes produced in decommissioning process of nuclear facilities has been investigated. Using an orthogonal experiment method, the effects on corrosion weight loss rate and decontamination factor of stainless steel have been studied in different conditions, including concentrations of HNO₃ and Ce(NH₄)₂(NO₃)₆, temperature of solution, and ultrasonic time. Results showed that temperature and Ce(NH₄)₂(NO₃)₆ concentration would be the major influence factors. A maximum corrosion rate of 8.07 μm/h was obtained with the optimal parameters of Ce(NH₄)₂(NO₃)₆ 0.15 mol/L), HNO₃ (1.0 mol/L) and 85 ℃ for the decontamination process. The corrosion behavior of coupons was observed by a scanning electron microscope (SEM), and the results showed that cavitation corrosion was caused by ultrasonic wave occurred on the surface of a decontaminated coupon. A decontamination experiment for a section of spent fuels storage tube for demonstration was conducted, and a decontamination factor of 158.8 was achieved. (authors)

[en] A plateau on the background inflaton potential can lead inflation into the ultraslow-roll (USR) stage, during which the primordial curvature perturbation $\mathcal{R}$ can still remarkably evolve outside the horizon. In this paper, the evolution of the Fourier mode ${\mathcal{R}}_k$ and the resulting power spectrum ${\mathcal{P}}_{\mathcal{R}}$(k) are systematically investigated. It is found that, when a scale crosses the horizon well before or after the USR stage, ${\mathcal{R}}_k$ only revolves around the origin in the complex plane. In contrast, if a scale crosses the horizon around the start of the USR stage, the argument of ${\mathcal{R}}_k$ will be nearly frozen and ${\mathcal{R}}_k$ will have a subsequent linear evolution accordingly, in which it may stop rather near or extremely far away from the origin, naturally explaining the entire growing stage of ${\mathcal{P}}_{\mathcal{R}}$(k) on small scales from the minimum to the peak. Moreover, there is a sharp dip in ${\mathcal{P}}_{\mathcal{R}}$(k), but the lowest point cannot reach 0 exactly. Our work provides a whole picture for ${\mathcal{R}}_k$ and ${\mathcal{P}}_{\mathcal{R}}$(k) in the USR inflation and will help our understanding of the relevant primordial black hole and gravitational wave physics.

[en] This paper deals with design principles, development and performance of a field measurement instrument for nuclear electromagnetic pulse (EMP) based on signal transmission through fiber. To determine the minimum band width this instrument needs, we analyze cutoff spectrum of a time domain double exponential signal, employing Fast Fourier Transform (FFT), and get its inverse transform signal. Then we design the circuit of laser device and the circuit of measuring device according to previous analysis. This instrument meets requirements of related regulations. Its specifications meet requirements of NEMP hazard protection research and can be of great significance to it. (authors)

[en] A perturbation in the inflaton potential can lead inflation into the ultra-slow-roll stage. The power spectrum of primordial curvature perturbation is thus substantially enhanced, generating abundant primordial black holes on small scales. In this paper, the power spectra are numerically calculated in the single-field inflation model, with one or two perturbations in the inflaton potential. The form of perturbation is constructed in an antisymmetric way, so that the inflaton neither rolls down rapidly after the ultra-slow-roll stage nor even stops in the ultra-slow-roll region. The primordial black holes with the abundance around 0.1 in one or two typical mass windows at $10^{-17}{M}_{\odot }$, $10^{-13}{M}_{\odot }$, and $30M_{\odot }$ can be achieved, without spoiling the nearly scale-invariant power spectrum on large scales.

[en] The Au₄₀Cu₃₀Pd₁₀Si₂₀ amorphous alloy samples with size of 5mm×0.02mm were prepared by melt-spinning method. The thermal analysis results show that the glass transition temperature T_g, the initial crystallization temperature T_x and the supercooled liquid region ΔT of Au₄₀Cu₃₀Pd₁₀Si₂₀ amorphous alloy are 404K, 440K and 36K, respectively, and the calculated glass transition temperature T_rg is 0.617, the parameter γ is 0.415. Compared with other Au-based amorphous alloys, the Au₄₀Cu₃₀Pd₁₀Si₂₀ alloy has good glass-forming ability (GFA), better thermal stability and good ductility. (paper)

[en] The lateral geometry 4H-SiC photoconductive semiconductor switches (PCSS) were fabricated on the vanadium compensated semi-insulating 4H-SiC substrate with the Si (0001) Ni/Au contacts deposited by magnetron sputtering. The effect of laser excitation energy on the photoelectric response and that on the state resistance of PCSS were investigated. The experimental results showed that a nano-second pulse electric signal was obtained when the PCSS was triggered with a 532 nm wavelength laser light. The on state resistance decreased from 295 Ω to 197 Ω when the laser excitation energy increased from 26.7 mJ to 43.9 mJ. Based on the combination theory, the relationship between the carrier concentration and time deduced when the PCSS was irradiated. The on state resistance simulated from the MATLAB is consistent with the experimental results. Finally, the two ways to reduce the on resistance of the switch are put forward. (authors)

[en] The implementation of urban development plans causes land use change, which can have significant environmental impacts. In light of this, environmental concerns should be considered sufficiently at an early stage of the planning process. However, uncertainties existing in urban development plans hamper the application of strategic environmental assessment, which is applied to evaluate the environmental impacts of policies, plans and programs. This study develops an integrated assessment method based on accounting uncertainty of environmental impacts. And the proposed method consists of four main steps: (1) designing scenarios of economic scale and industrial structure, (2) sampling for possible land use layouts, (3) evaluating each sample's environmental impact, and (4) identifying environmentally sensitive industries. In doing so, uncertainties of environmental impacts can be accounted. Then environmental risk, overall environmental pressure and potential extreme environmental impact of urban development plans can be analyzed, and environmentally sensitive factors can be identified, especially under considerations of uncertainties. It can help decision-makers enhance environmental consideration and take measures in the early stage of decision-making.

[en] Egongshan volcanic basin which is rich in the uranium-polymetallic mineral in the Gan-Hang Tectonic volcanic belt. On the basis of collecting the previous exploration results, this paper has summarized the mineralization geological characteristics of uranium, gold and silver, analyzed the metallogenic conditions of Uranium-polymetallic deposits in Volcanic Basin from Ore-forming elements gathering, structure, magmatic activity, wallrock alteration, cryptoexplosion and mantlederived material, etc. It is considered that the strong volcanic magma activity and function in Mesozoic has provided favorable basic geological conditions for the volcanic-cryptovolcanic hydrothermal Uranium-polymetallic deposits in the volcanic basin. It is suggested that study on the relationship between cryptoexplosive breccia and mineralization and whether the mantlederived material involves in the mineralization should be strengthened. (authors)

[en] Recycling of scrap iron and steel is the key steps to realize the sustainable development of iron and steel industry. Considering the existing processing methods of crap iron and steel are extensive, and the processing depends on the experience of the staff or manual measurement, which is easy to cause resource waste and secondary pollution. Aiming at the difficulty of the processing decision-making of scrap iron and steel, a method of scrap iron and steel processing technology decision-making based on case reasoning is proposed. After analysing the sources and classification of the scrap iron and steel, and combining with the main processing methods, the modular case base is founded. Extracting the key features of scrap iron and steel, and using the entropy weight method and analytic hierarchy process (AHP) to calculate the weight of each characteristic element, the comprehensive similarity of the index of case is calculated to obtain the processing method. The feasibility and effectiveness of the decision method are verified by taking the scrap iron and steel processing of a metal resource company as an example. (paper)

[en] The three cavities dielectric wall proton accelerator is systemically simulated by the self-developed 3D particle simulation software. On this basis, the transit time of protons in three cavities shall be calculated and the timing optimization design between cavities shall be achieved. The impressed voltage peak value is 100 kV. The width at top is 1ns and it is 10 ns at half maximum. The thickness of insulation micro reactor is 2.0 cm. The proton initial energy is 40 keV. The tungsten mesh is added to accelerating electrode. The simulation results are the following: When the voltage lasts 6.5 ns, the H⁺ which goes into high insulation gradient material shall get a maximum 90.84% acceleration efficiency while passing the first cavity, and the corresponding transit time is 5.668 ns. When the voltage triggers in the second cavity 4.5 ns behinds the first cavity, the H⁺ shall get a maximum 94.77% acceleration efficiency while passing the third cavity, and the corresponding transit time is 3.545 ns. When the voltage triggers in the third cavity 3.0 ns behinds the second cavity, the H⁺ shall get a maximum 97.30% acceleration efficiency while passing the second cavity, and the corresponding transit time is 3.018 ns. The total time of the maximum energy H⁺ transiting the three cavities is 12.231 ns. The acceleration efficiency of total H⁺ is 94.31%. When the proton beam center enters the first cavity and falls behind the pulse voltage trigger in 6.5 ns, with the delay time between first and second cavities, the second and third cavities are 4.5 ns and 3.0 ns respectively. The H⁺ of proton beams whose lengths are 2.5 ns and 4.0 ns shall be accelerated above 90% and 80% respectively. (authors)