[en] The extraction of three kinds of amido podands, N,N,N'N'-tetrabutyl-3-oxa-pentanedi-amide (TBDGA), N,N,N'N'-tetra-isobutyl-3-oxa-pentanediamide(TiBDGA) and N,N,N'N'-tetra-butyl-3, 6-dioxa-oct-anediam-ide(TBDOODA) on U(VI),Pu(IV),Am(III), Eu(III) and other metal ions is studied in nitric acid solutions. 40% octanol-kerosene is chosen as diluent to eliminate third phase and emulsion. TBDGA and TiBDGA show extraction selectivity to An(III) and Ln(III) much higher than to U(VI) and Pu(IV). Fe, Ru and Mo is poorly extracted by the three kinds of amid podands in 2∼3mol/L HNO3 sloutions. Aiming to eliminated interface crud when using simulated HLLW solution in the system of 0.2mol/L TBDGA/Octanol+kerosene, acetohydroxyamic acid was adapted. Distribution ratio of zirconium was decreased when adding acetohydroxyamic acied in aqueous solution, and interface crud disappeared as mixing extractant with HLLW. The counter-current extraction test is carried out in a set of miniature mixer-settler, with 0.2mol/L TBDGA/ 40% octanol-kerosene as extractant to separated U(VI), Pu(IV), Am(III) and Eu(III) from simulated high level liquid waste(HLLW) solution. In battery A, lanthanides and actinides are coextracted into organic phase with the recovery of 99.98% for U(VI),>99.99% for Pu(IV), and>99.99% for Am(III) and Eu(III) respectively. In battery R1, 99.99% U, 86.2% Pu and a part of Am or Eu are stripped into aqueous phase by 0.2mol/L acetohydroxyamic acid (AHA) in 0.01mol/L HNO3 solution. In battery R2, Am, Eu and remained Pu are completely back-extracted by 0.2mol/L AHA. This separation process contains no salt reagent, and it is not necessary to dilute HLLW feed

[en] The chemical behavior of Np is influenced by many factors, such as U(IV), hydrazine, Pu and Tc, which coexist in U/Pu separation stage of PUREX process. Firstly, the reduction of Np(V) to Np(IV) by Tc(IV) was studied in nitric acid media, and the rate equation could be expressed as -d[Np(V)]/dt = k[Np(V)][Tc(IV)]^0.8[HNO₃]^1.2, k = 28.5 ± 0.9 (L/mol)²/min at 25 , the activation energy was E_a = 70.0 kJ/mol. Thereafter, the chemical behavior of Np was investigated in aqueous nitric acid solution containing Tc(VII), U(IV) and N₂H₄. Np(V) was reduced to Np(IV) quickly, Tc(VII) was reduced to Tc(IV) and U(IV) was oxidized to U(VI) at the same time. Thereafter Np(IV) was entirely reoxidized to Np(V) when U(IV) and hydrazine were completely consumed. The fast reduction of Np(V) was mainly ascribed to Tc(IV). In addition, Tc(VII) and nitric acid had little influence on the fast oxidation of Np(IV). (orig.)

[en] Highlights: • CDRX of Nbss dominates the softening of hot-compressed Nb-Si based alloy. • Nb₅Si₃ cracking leads to the initial rapid softening of the alloy. • CDRX of Nb₅Si₃ is obviously activated after a height reduction of 30%. • The size of silicide particles decreases with the increase in strain. • Silicide particles are refined by Nb₅Si₃ cracking and Nbss interpenetration. The flow softening behaviors of a Nb-Si based ultrahigh temperature alloy during hot compression to height reductions of 10, 30 and 60% respectively at 1410 °C have been investigated. The flow characteristics during dynamic softening of the alloy have been revealed. The evolution of deformed microstructure during compression is that the coupled Nbss/Nb₅Si₃ eutectics have been gradually broken down accompanied by the development of continuous Nbss matrix with evenly dispersed silicide particles. The softening mechanisms of the Nb-Si based ultrahigh temperature alloy have been discussed based on the orientation variation of both Nbss and Nb₅Si₃ phases, the deformed microstructure and its flow characteristics. The softening of the alloy is mainly dominated by the continuous dynamic recrystallization (CDRX) of Nbss. The CDRX of Nb₅Si₃ has occurred at a much more sluggish rate and has just been significantly activated with the height reduction increasing from 30 to 60%. The gradual refinement of silicide particles has been observed with increase in strain.

[en] The removal of minor actinides (mainly Am, Cm and Np) from the high-level waste would remarkably reduce the necessary storage time. Recently developed, a tridentate ligand, N,N,N',N'-tetraoctyl diglycolamide (TODGA), has been identified as one of the most powerful extractants being considered for the partitioning of trivalent actinides and lanthanides. In the present paper, the extraction kinetics behavior of Am(III) in TODGA/n-dodecane-HNO₃ system has been studied, dependent on various parameters such as the stirring speed, the interfacial area, the extractant concentration in n-dodecane, the extracted ions concentration, the acidity of aqueous phase and the temperature. The results show that: the extraction process is controlled by diffusion mode under 130 rpm of stirring speed and by chemical reaction mode above 150 rpm. The extraction rate equation is given in the paper and the apparent extraction rate constant of Am(III) by TODGA/n-dodecane in 170 rpm and at 25 Celsius degrees is k=(24.2±3.4)*10^-3 mol^-2.18*L^2.18*min^-1*cm. The initial extraction rate of Am(III) by TODGA/n-dodecane at 170 r/min and 25 Celsius degrees increases with increasing temperature, and the apparent active energy is calculated to be E_a=(25.94±0.98) kJ/mol

[en] Objective: The status of regional nodal involvement bears clinical significance in management of patients of oral squamous cell carcinoma(OSCC). The aim of this study was to evaluate the feasibility of ⁹⁹Tc^m (V)-dimercaptosuccinic acid (DMSA) imaging after local injection in detecting neck lymph node metastases in OSCC. Methods: ⁹⁹Tc^m (V)-DMSA was injected around tumor in 30 patients with primary OSCC. SPECT and planar scintigraphy were performed at 2 h after injection. Any focal uptake in neck was defined as positive lymph node. The ROI over the positive uptake lesion was drawn and the average radioactivity value was in comparison to that on the contra lateral side calculated. The scintigraphic results were then compared with postoperative pathological findings. Results: The sensitivity, specificity and accuracy of ⁹⁹Tc^m (V)-DMSA imaging in detecting metastatic lymph nodes were 84.6% (11/13), 82.4% (14/17) and 83.3% (25/30), respectively. The focal uptake values were much higher than the contra lateral regions in the positive patients (P=0.0001). Conclusion: ⁹⁹Tc^m(V)-DMSA scintigraphy after local tracer injection may be feasible to detect regional metastatic lymph nodes in patients with OSCC. (authors)

[en] The extraction behavior of U, Np, Pu, Am, rare earth elements and Sr from nitric acid solutions by TODGA/dodecan, DHOA/dodecane and TODGA-DHOA/dodecane were investigated, respectively. Based on experimental results, a separation process was proposed for minor actinide isolation from high level liquid waste (HLLW): the TODGA-DHOA/kerosene system. The multi-stage counter-current cascade experiments were carried out for the purpose by 0.1 mol/l TODGA-1.0 mol/l DHOA/kerosene with miniature mixer- settler contactor rigs (8 stages for extraction, 6 stages for scrubbing, 8 stages for first stripping, 8 stages for second stripping). The results show that the recovery efficiencies of the actinides and lanthanides are more than 99.9%, whereas less than 1% Sr was extracted by 0.1 mol/l TODGA - 1.0 mol/l DHOA/kerosene. The stripping efficiencies of U, Np and Pu are more than 95% in the first stripping step by 0.5 mol/l HNO₃ + 0.5 mol/l AHA(aceto-hydroxamic acid), all of the remained actinides and lanthanides can be stripped by 0.01 mol/l HNO₃ in the second stripping step. 99% Sr was extracted by 0.1 mol/l TODGA/kerosene, so Sr can be recovered efficiently directly from the raffinate by 0.1 mol/l TODGA/kerosene. (authors)

[en] A theoretical investigation of the anisotropy of face-centered-cubic (FCC) and body-centered (BCC) medium entropy alloys (MEAs) based on the first-principle calculations has been implemented. The electronegativity difference Δ_χ, mixing enthalpy ΔH_mix, range of electronegativity R_χ and total charge transfer have been considered. All elastic anisotropies of the selected MEAs change monotonously with the electronegativity difference Δ_χ, more specifically, the anisotropy decreases with decreasing electronegativity difference Δ_χ. A detailed investigation of electronic structure reveals that charges are mainly accumulated around the atom with minimal Pauling electronegativity (χ) and valence electron concentration (VEC), resulting in a high anisotropy of MEAs. For Al-containing MEAs, a substantial number of total charge transfer will lead to a great anisotropy. In addition, the range of electronegativity R_χ can be used to assist in identifying the anisotropy in the localized electron distribution.

[en] Objective: To explore the feasibility of EPR in vivo fingernail dosimetry to address the difficulty in separating mechanically induced signals from fingernail EPR dosimetry for need of nuclear medical emergency aid. Methods: Using the specially designed EPR in vivo measurement system, uncut fingernails were measured to obtain the characteristics of EPR signal without mechanically induced signals. The in vivo fingernail experiment was carried out to evaluate the impact of in vivo condition on the spectra. Actual in vivo measurement experiment was conducted to evaluate the interference of the in vivo condition on EPR spectra. Results: The background signal distribution of uncut fingernails was obtained and background signals had no significant difference between male and female (P > 0.05). The dose response curve in the range of 2-10 Gy was established, and the half-life of the fingernail radiation-induced signal was approximately 5 d. The water treatment combined with temperature-changing was established for restoring the background signal. EPR signal obtained after restoring treatment has no significant difference with background signal (P > 0.05). The EPR spectra of in vivo fingernails were obtained. Conclusions: The EPR spectra without mechanically induced signals can be acquired by this method. The feasibility of the in vivo fingernail EPR dosimetry is preliminarily verified. (authors)

[en] Highlights: • Flexible layered RuO₂·1.18H₂O/PEDOT-PSS film was prepared through filtration. • The film had good mechanical property and high electrical conductivity. • The film showed high specific capacitance of 591 F g^-1 at 10 mV s⁻¹. • The film exhibited high energy density of 18 Wh kg⁻¹ at 5000 W kg⁻¹. • The capacitance retention of the film was 91.5% after 5000 cycles at 10 A g⁻¹. A micron-thick flexible layered RuO₂·1.18H₂O/PEDOT-PSS film with high electric conductivity of about 306 S cm⁻¹ (sheet resistance of film of 7.1 Ω sq⁻¹) was prepared using commercial PEDOT-PSS dispersion and RuO₂·1.18H₂O nanoparticles through a simple, low-cost vacuum filtration technology. The layered flexible film could be used as a rope to hang up 300 gram weight and as a conducting wire in a circuit to light a blue LED lamp. The symmetrical supercapacitor based on the layered flexible films showed high specific capacitance of 591 F g⁻¹ (volumetric specific capacitance of 530 F cm⁻³) at 10 mV s⁻¹, excellent long-term cycling stability (capacitance retention of 91.5%) after 5000 cycles, and high energy density of 18 Wh kg⁻¹ at high power density of 5000 W kg⁻¹. The flexible film as function as current collector and active material simultaneously will have practical application in miniaturized flexible supercapacitors.

[en] In this paper the synchronization for two different fractional-order chaotic systems, capable of guaranteeing synchronization error with prescribed performance, is investigated by means of the fractional-order control method. By prescribed performance synchronization we mean that the synchronization error converges to zero asymptotically, with convergence rate being no less than a certain prescribed function. A fractional-order synchronization controller and an adaptive fractional-order synchronization controller, which can guarantee the prescribed performance of the synchronization error, are proposed for fractional-order chaotic systems with and without disturbances, respectively. Finally, our simulation studies verify and clarify the proposed method. (paper)