[en] The fate and transport of toxic metal ions and radionuclides in the environment is generally controlled by sorption reactions. The extent of sorption of divalent metal cations is controlled by a number of factors including cosorbing or complexing. In this work, the effects of pH, humic acid HA/Co(II) addition orders, ionic strength, concentration of HA, and foreign cations on the Co(II) sorption on γ-Al₂O₃ in the presence of HA were investigated. The sorption isotherms of Co(II) on γ-Al₂O₃ in the absence and presence HA were also studied and described by using S-type sorption model. The experimental results showed that the Co(II) sorption is strongly dependent on the pH values, concentration of HA, but independent of HA/Co(II) addition orders, ionic strength, and foreign cations in the presence of HA under our experimental conditions. The results also indicated that HA enhanced the Co(II) sorption at low pH, but reduced the Co(II) sorption at high pH. It was hypothesized that the significantly positive influence of HA at low pH on the Co(II) sorption on γ-Al₂O₃ was attributed to strong surface binding of HA on γ-Al₂O₃ and subsequently the formation of ternary surface complexes such as ≡S-OOC-R-(COO^-)_xCo^2-x. Chemi-complexation may be the main mechanism of the Co(II) sorption on γ-Al₂O₃ in the presence of HA. (author)

[en] A miniature shaping amplifier and gate integrator as its applications, operation principle, circuit structure and circuit design are introduced. This amplifier is mainly used in the amplification and sampling for semiconductor detector, proportional counter and scintillation detector and in the analysis and study of sample and hold circuits of multichannel pulse amplitude analyzer ect

[en] Objective: To investigate the value of CT spectral imaging to evaluate bone mass in patients with Graves' hyperthyroidism, and the changes of bone mass before and after ¹³¹I therapy. Methods: Sixty-eight patients(13 males, 55 females; age 40.6 ± 10.7 yr) with Graves' hyperthyroidism who received ¹³¹I therapy from June to October 2015 were involved in our study. The bone mineral density (BMD) of lumbar was obtained by dual energy X-ray absorptiometry (DXA), and the calcium-water concentration of L3 was measured by CT spectral imaging before ¹³¹I therapy. Pearson correlation analysis and linear regression were performed to explore the relationship between them. All clinical data were collected to assess the efficacy of ¹³¹I therapy after 6 months. CT spectral imaging was repeated, in order to compare the changes of bone mass using comparative t-test. Results: Of these patients with Graves' hyperthyroidism, 30.9% (21/68) patients with osteopenia and 10.3% (7/68) patients with osteoporosis were diagnosed according to the results of BMD by DXA. The calcium (water) densities of L3 were (64.33 ± 14.65), (48.2± 4.45) and (41.65 ± 1.21) g/cm³ in patients with normal bone mass, bone loss and osteoporosis, respectively. The differences between the three groups were statistically significant (x² = 35.811, P < 0.001). The bone mineral density of L3 were (1.252 ± 0.305), (1.103 ± 0.254) and (0.539 ± 0.066) g/cm³ in patients with normal bone mass, bone loss and osteoporosis, respectively. The differences between the three groups were statistically significant (F = 12.968, P < 0.001). The calcium-water concentrations of L3 (g/cm³) were highly correlated with BMD values (g/cm²) of lumbar determined by DXA(r = 0.794, hypothesis testing standard α = 0.01, t = 10.605, P < 0.001). Equation of linear regression:the calcium-water concentration of L3 = 24.485 + 34.529 BMD value of lumbar. Furthermore, after ¹³¹I therapy, the calcium-water concentrations of L3 increased (t = 7.86, P < 0.001) in the cured group of patients. But there weren't significant difference in the uncured group of patients (t = 2.29, P = 0.062). Conclusions: CT spectral imaging can be used to evaluate bone mass in patients with Graves' hyperthyroidism. Bone mass can be improved with remission of hyperthyroidism after ¹³¹I therapy. (authors)

[en] First-principle density functional theory calculations were performed to explore electronic and structural properties of β-(Al_xIn_yGa_1−x−y)₂O₃ quaternary alloys with both Al-content (x) and In-content (y) ranging from 0% to 18.75%. The β-(Al_xIn_yGa_1−x−y)₂O₃ quaternary alloys exhibit indirect band gap property with the bandgap energy varying from 4.432 to 5.171 eV. Electron effective masses are also presented for β-(Al_xIn_yGa_1−x−y)₂O₃ quaternary alloys, showing a general reduction with In-content increases but a general increment with Al-content increases in the material. Further analysis indicates the possibility of achieving lattice-matched or near-lattice-matched β-(Al_xIn_yGa_1−x−y)₂O₃/β-Ga₂O₃ structures system, which is critical for high performance field effect transistor and deep ultraviolet photodetector applications. Our work shows that the β-(AlInGa)₂O₃ alloys with proper tuning of Al- and In-content have strong potential to be used as part of the epitaxial layers for β-Ga₂O₃-based material system. (paper)

[en] A series of carbon nanotube (CNTs)-supported copper-cobalt catalysts were prepared and investigated in a slurry reactor for their ability to selectively convert syngas into higher carbon number alcohols. The 7.5Cu7.5Co/CNTs catalyst achieved superior selectivity towards the formation of ethanol (30.1%) and C₂₊ alcohols (57.7%), while the 10Co5Cu/CNTs catalyst exhibited the largest alcohol space-time yield (372.9 mg g_cat^-1 h^-1). However, the pure Cu (¹⁵Cu/CNTs) catalyst displayed negligible activity. Cobalt reduction was enhanced in the presence of copper. In addition to the Cu⁰-Co⁰ center, Co⁰ -Co²⁺ also presented dual active sites for higher alcohols synthesis, the Co²⁺ site could terminate carbon chain growth to produce alcohols. The ratio of Cu/Co considerably influences the metal particle properties-synergistically effecting the active species. (author)

[en] The surface and sorption properties of kaolinite were analyzed as a function of silicate. Batch experiments indicate that the U(VI) sorption is promoted by the addition of silicate at low pH while is depressed at high pH. The sorption was acceptably predicted by the formation of a ternary silicate surface complex under the experimental conditions. The pseudo-second order kinetic model fit the sorption kinetics better. The sorption isotherms are more in accordance with Langmuir model and the thermodynamic parameters indicate a spontaneous and endothermic sorption process. (author)

[en] The surface property of attapulgite was investigated by N₂-BET surface area and zeta potential analysis in this paper. Solution pH had a remarkable effect on the sorption process, indicated an inner-sphere complexation. Humic acid (HA) in the solution enhanced U(VI) sorption significantly at pH < 5.0, while decreased U(VI) sorption obviously at pH > 9.0. The characteristic fluorescence changes of HA indicated that a strong chemical reaction occurred between the functional groups in HA and UO₂²⁺. The sorption was a spontaneous and endothermic process with increased entropy, and the increase in temperature would benefit the sorption. (author)

[en] The temperature effect on the co-sequestration process receives little attention. Herein, kinetic and thermodynamic studies on the co-sequestration of Eu(III) and phosphate by γ-Al_2O_3 were investigated by batch experiments. The standard thermodynamic parameters (ΔH0, ΔS0, and ΔG0), the activation thermodynamic parameters (ΔHhashmark, ΔShashmark, and ΔGhashmark), and the activation energy (EA) for the co-sequestration process were obtained. Based on E_A and ΔShashmark values, Eu(III) and phosphate co-sequestration is controlled by chemical reactions on γ-Al_2O_3 and by an associative mechanism. This work highlights the temperature effect on the co-sequestration of Eu(III) and phosphate in a geological environment. (author)

[en] Highlights: • A solar tube integrating the photo-electric and photo-thermal conversion is demonstrated. • The titanium having small plasma frequency is selected to enable wide absorption of photon energy for thermal conversion. • A sandwiched membrane of high transparency and conductivity is developed for tubular solar cells. -- Abstract: A solar cell, capable of directly converting solar energy into electricity, bears a Shockley-Queisser limit of about 31% based on a single pn junction. In general, less than 50% of the solar irradiation spectrum (mostly in the ultraviolet and visible regions) can be utilized for the conversion. As such, the theoretical utilization rate is less than 15% in a single device, with most of the extra energy being lost as heat. It is thus appealing to enhance the energy utilization with devices that could collect the heat loss. In this study, we design and demonstrate a solar tube to realize photo-electric and photo-thermal conversions simultaneously. The key point is the use of titanium tube: (1) it has a small plasma frequency to enable wide absorption for thermal conversion; (2) it accommodates TiO₂ nanotube arrays to solve the cracking problem under tensile stress. A sandwiched membrane of high transparency and conductivity is developed for hole transport and collection. Eventually, a total energy efficiency of about 25.2% is obtained. Such a solar tube is anticipated to highly boost the utilization rate of solar energy with judiciously designed structure.

[en] [Background] The disposal of high-level radioactive wastes is critical for sustainable development of nuclear energy. And the adsorption, diffusion and migration behaviors of radionuclides in the environment depend on the chemical species in the system. [Purpose] The paper aims to understand the speciation distribution of uranium and adsorption behavior on quartz and hydrous ferric oxide. [Methods] The speciation distribution and sorption of uranium are calculated by chemical speciation analysis software CHEMSPEC, which is developed by Peking University Nuclear Environmental Group. [Results and Conclusions] The calculation results indicate that uranium exists as UO₂(CO₃)₃^4- and UO₂(CO₃)₂^2- in the Beishan groundwater. And under acidic conditions, uranium mainly exists as U(OH)₄(aq). While in neutral or weak alkaline conditions, the main species are UO₂(CO₃)₂^2- and UO₂(CO₃)₃^4-. When the solution is in strong alkaline conditions, most of uranium exists as UO₂(OH)₃^-. And U(IV) is stable in the redox condition, while U(VI) is stable in the oxide condition. The concentration of different ions also has influence on the speciation distribution of uranium, and in the order of HCO₃^- > F^- > SO₄^2- > Cl^-. With the increasing number of pH, the sorption extent of U(VI) on quartz is lager. And the maximum adsorption is at pH = 4.3. When it comes to U(VI) sorption on hydrous iron oxide, the greatest sorption is at pH = 5.7 ∼ 8.2.(authors)