摘要：
Separation of palladium from high level liquid waste (HLLW) not only manages the dispose of HLLW, but could also aid in overcoming the shortage of palladium resources. Herein, three novel adsorbents, namely, 2-mercap-tobenzimidazole (MBI)/XAD7HP, 2-mercaptobenzothiazole (MBT)/XAD7HP, 2-mercaptobenzoxazole (MBO)/ XAD7HP were prepared by vacuum impregnation method using Amberlite XAD7HP resin (XAD7HP) as the carrier for the selective separation of Pd(II) from simulated HLLW. SEM-EDS (Scanning Electron Microscopy), BET (Brunauer-Emmett-Teller) and PXRD (Powder X-ray diffraction) analysis showed that the ligands were successfully impregnated into the carrier. The saturated adsorption capacities of MBI/XAD7HP, MBT/XAD7HP, MBO/XAD7HP in 0.5 M HNO3 were 126.2 mg Pd/g, 137.6 mg Pd/g, 98.4 mg Pd/g, respectively, and excellent adsorption and separation performance towards Pd(II) (SFPd/other metals > 500 and Kd > 104 mL/g from 0.1 to 4 M HNO3) were also achieved. The adsorption kinetics and adsorption isotherms for Pd(II) matched well with pseudo-second-order kinetic model and Langmuir model, indicating that the adsorption for Pd(II) by three ad-sorbents were monolayer chemical adsorption. The adsorption mechanism was analyzed by FT-IR, XPS combined with DFT calculation. The extremely high selectivity of three adsorbents towards Pd(II) among 15 metal ions is due to the soft N and S donor atoms at ligands which have good affinity for Pd(II) in HNO3 solution. As MBT/ XAD7HP exhibited the best adsorption and separation properties, it is supposed to have more application po-tential for the separation of Pd(II) from HLLW.
摘要：
Palladium (Pd) in high level liquid waste (HLLW) is a valuable alternative resource besides its natural reserves. On the other hand, the presence of Pd has extremely negative impacts on the vitrification process of HLLW. To separate Pd from HLLW, a novel silica-based adsorbent named HEMAP/SiO2-P was designed and prepared by using 2-hydroxyethyl-2-methyl-2-propenoate phosphate as the functional group donor, dichloromethane as the diluent and styrene–divinylbenzene modified silica particle as the carrier. The experimental results reveal that HEMAP/SiO2-P possesses excellent adsorption selectivity (SFPd/other metals > 183.2) and large adsorption capacity (393.4 mg/g) towards Pd in 1 M HNO3 solution. Moreover, column experiments show that the adsorbent can effectively separate Pd from other coexisting metal ions in simulated HLLW with the recovery yield of 99.4%. The experimental and characterization analyses as well as DFT calculations confirm that the adsorption mechanism involves ion exchange between Pd(II) and H+ (in P-OH) accompanied by the transfer of charge.
作者机构：
[Wang, Youbin; Chen, Zhiwen; Hu, Minjie] GuangXi Univ, Sch Resources Environm & Mat, Nanning 530000, Peoples R China.;[Wang, Youbin; Chen, Zhiwen; Hu, Minjie] State Key Lab Featured Met Mat & Lifecycle Safety, Nanning 530000, Peoples R China.;[Ning, Shunyan; Wei, Yuezhou] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.
通讯机构：
[Youbin Wang] S;School of Resources, Environment and Materials, GuangXi University, Nanning 530000, China<&wdkj&>State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, Nanning 530000, China
摘要：
The electrochemical behavior and electrodeposition mechanism of indium in acidic aqueous solution were studied using cyclic voltammetry (CV), chronoamperometry by electrochemical quartz crystal microbalance (EQCM). The cyclic voltammetry of indium on Pt electrode was more complex than that on glassy carbon (GC) electrode. Only one reduction peak and an oxidation peak could be seen in the CV curve of GC, which were attributed to the electrodeposition and dissolution of indium, respectively. In contrast, an extra reduction and several oxidation peaks were observed in the CV curve on Pt electrode. EQCM results illuminated the difference of CV curves between the two electrodes. The hydrogen reduction takes place simultaneously during indium electrodeposition on the Pt electrode, while on the GC electrode, the hydrogen evolution is suppressed. Passivation of indium during the stripping of deposit on Pt electrode is confirmed. The participation of low-valent indium ions is also confirmed in the dissolution process by the analysis of EQCM results. The analysis of current transients and SEM images indicates that the indium electrodeposition on GC and Pt follows progressive nucleation and three-dimensional growth controlled by diffusion, and the diffusion coefficient of In3+ on Pt and GC was calculated as (1.31 +/- 0.15)x10- 5 cm2 s-1 and (1.2 +/- 0.1)x10- 5 cm2 s- 1, respectively. By separating the electrodeposion current from total current using EQCM, the current characteristics of nucleation and growth of indium which was covered by the hydrogen evolution can be reproduced. The current due to indium electro-deposition on Pt substrate was calculated from the mass change signal recorded by EQCM, which fitted well with the nonlinear fitting result.
作者机构：
[He, Chunlin; Fujita, Toyohisa; Han, Zhenyao; Chen, Hao] Guangxi Univ, Sch Chem & Chem Engn, Nanning 530004, Peoples R China.;[Dodbiba, Gjergj] Univ Tokyo, Grad Sch Engn, Tokyo 1138656, Japan.;[Otsuki, Akira] Univ Adolfo Ibanez, Fac Ingn & Ciencias, Diagonal Torres 2640,11 Penalolen, Santiago 7941169, Chile.;[Otsuki, Akira] Lulea Univ Technol, Waste Sci & Technol, S-97187 Lulea, Sweden.;[Wei, Yuezhou] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Fujita, Toyohisa] S;School of Chemistry and Chemical Engineering and College of Resources, Environment and Materials, Guangxi University, Nanning, 530004, China.
摘要：
Nanobubbles have been applied in many fields, such as environmental cleaning, material production, agriculture, and medicine. However, the measured nanobubble sizes differed among the measurement methods, such as dynamic light scattering, particle trajectory, and resonance mass methods. Additionally, the measurement methods were limited with respect to the bubble concentration, refractive index of liquid, and liquid color. Here, a novel interactive force measurement method for bulk nanobubble size measurement was developed by measuring the force between two electrodes filled with bulk nanobubble-containing liquid under an electric field when the electrode distance was changed in the nm scale with piezoelectric equipment. The nanobubble size was measured with a bubble gas diameter and also an effective water thin film layer covered with a gas bubble that was estimated to be approximately 10nm based on the difference between the median diameter of the particle trajectory method and this method. This method could also be applied to the solid particle size distribution measurement in a solution.
作者：
Liu, Y.;Zhang, Y. P.;Liu, J. C.;Guo, C.;Yang, C. G.;...
期刊：
Journal of Instrumentation,2023年18(3):T03002 ISSN：1748-0221
作者机构：
[Li, C.; Tang, Q.; Xu, Z. F.; Liu, Y.; Guan, T. Y.] Univ South China, Sch Nucl Sci & Technol, Hengyang, Peoples R China.;[Guo, C.; Zhang, Y. P.; Zhang, P.; Liu, J. C.; Wang, S. B.; Yang, C. G.] Chinese Acad Sci, Inst High Energy Phys, Expt Phys Div, Beijing, Peoples R China.;[Guo, C.; Zhang, Y. P.; Zhang, P.; Liu, J. C.; Yang, C. G.] Univ Chinese Acad Sci, Sch Phys, Beijing, Peoples R China.;[Guo, C.; Zhang, Y. P.; Zhang, P.; Liu, J. C.; Yang, C. G.] State Key Lab Particle Detect & Elect, Beijing, Peoples R China.
关键词：
Heavy-ion detectors;Gaseous detectors
摘要：
The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multipurpose underground liquid scintillator detector, was proposed for the determination of the neutrino mass hierarchy as primary physics goal. The central detector will be submerged in a water Cherenkov detector to lower the background from the environment and cosmic muons. Radon is one of the primary background sources. Nitrogen will be used in several sub-systems, and a highly sensitive radon detector has to be developed to measure its radon concentration. A system has been developed based on 222Rn enrichment of activated carbon and 222Rn detection based on the electrostatic collection. This paper presents the detail of a mu Bq/m3 level 222Rn concentration measurement system and gives detailed information about how the adsorption coefficient was measured and how the temperature, flow rate, and 222Rn concentration affect the adsorption coefficient.
通讯机构：
[Zhou, QZ ] U;Univ South China, Sch Nucl Sci & Technol, 28 Changshengxi Rd, Hengyang 421001, Peoples R China.
关键词：
Rn-220 progeny;Rn-220 chamber;Fan frequency;Aerosol particle;Cyclic loss rate
摘要：
To accurately measure and evaluate the radiation dose of Rn-220 and its progeny, a Rn-220 chamber with an airflow model has been developed and studied, but it is difficult to take into consideration many relevant factors such as adsorption, wall attachment, and decay. This paper proposes the concept of cyclic loss rate of Rn-220 progeny based on progeny supplement technology, establishes a theoretical formula to calculate the cyclic loss rate, and analyzes the relationship between cyclic loss rate, fan frequency, and aerosol particle size through both experiments and modelling methods. The feasibility of the cyclic loss rate model is experimentally verified.
通讯机构：
[Xionghui Fei] S;School of Nuclear Science and Technology, University of South China, Hengyang, People’s Republic of China<&wdkj&>Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, People’s Republic of China
摘要：
Hydrolysis is considered the rate-limiting step in the anaerobic digestion of food waste. In this study, the effect of gamma-ray irradiation on the enzymatic hydrolysis efficiency of polysaccharides, proteins and oils in food waste was performed. The cooked rice, tofu and soybean oil were irradiated with Co-60-gamma rays. The samples treated with different doses (0, 8.28, 16.56, 24.84 kGy) of irradiation were subjected to enzymatic hydrolysis experiments at constant temperature. The results show that gamma-ray irradiation can enhance the sensitivity of starch, protein and oil to the corresponding enzymes, so that their enzymatic hydrolysis rate and degree can be improved.
通讯机构：
[Bin Wu] I;[Xueyu Gong] S;School of Nuclear Science and Technology, University of South China, Hengyang 421001, People's Republic of China<&wdkj&>Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
关键词：
NBI plus ICRF synergy;beam-RF interactions;fast ions;neutron emission rate
摘要：
Following an upgrade of the neutral beam injection (NBI) system, obvious synergy between combined NBI and ion cyclotron resonance frequency (ICRF) heating was observed in recent experiments conducted at EAST. To investigate the effects of beam-ions accelerated by radiofrequency (RF) wave, analyses are performed by using TRANSP code based on the experimental results. The calculated results argue that only a small fraction of the ICRF power is absorbed by the beam ions in the ICRF + NBI synergistic heating of the (H)D plasma. To enhance the beam-RF interactions in synergistic heating and achieve high plasma performance of EAST, different experimental conditions, including multiple injection powers and diverse beam injection options, were explored. Beam injected fast ions are passing particles, trapped particles observed when synergy heating between ICRF and NBI. In particular, by varying the injection direction of the beam ions it was observed that more tangential beam yields better synergy in comparison with more perpendicular beam. The neutron emission rate of D-D fusion in tokamaks is improved and less fast ion loss is produced with tangential NBI + ICRF heating. Also, the effect of the ratio P (ICRF)/P (NBI) on ICRF + NBI combined heating is demonstrated, the higher power boosts the fusion enhancement. The study of the performed synergistic heating provides an important reference for the subsequent combined NBI + ICRF heating experiments on EAST.
期刊：
EUROPEAN PHYSICAL JOURNAL PLUS,2023年138(2):1-26 ISSN：2190-5444
通讯作者：
Junhui Liao
作者机构：
[Liao, Junhui] Brown Univ, Dept Phys, Hope St 182, Providence, RI 02912 USA.;[Peng, Zhaohua; Liang, Zhuo; Zhou, Jiangfeng; Liao, Junhui; Zhang, Lifeng; Zheng, Jian] China Inst Atom Energy, Div Nucl Phys, Sanqiang Rd 1, Beijing 102413, Peoples R China.;[Gao, Yuanning] Peking Univ, Sch Phys, ChengFu Rd 209, Beijing 100084, Peoples R China.;[Ouyang, Zebang] Univ South China, Sch Nucl Technol, ChangSheng West Rd 28, Hengyang 421009, Hunan, Peoples R China.;[Zhang, Lei] China Inst Atom Energy, Div Nucl Synth Technol, Sanqiang Rd 1, Beijing 102413, Peoples R China.
通讯机构：
[Junhui Liao] D;Department of Physics, Brown University, Providence, USA<&wdkj&>Division of Nuclear Physics, China Institute of Atomic Energy, Fangshan district, Beijing, China
摘要：
Dark matter (DM) is one of the most critical questions to be understood and answered in fundamental physics today. Observations with varied astronomical and cosmological technologies strongly indicated that DM exists in the Universe, the Milky Way, and the Solar System. Nevertheless, understanding DM under the language of elementary physics is still in progress. DM direct detection tests the interactive cross-section between galactic DM particles and an underground detector’s nucleons. Although weakly interacting massive particles (WIMPs) are the most discussed DM candidates, the null-WIMPs conclusion has been consistently addressed by the most convincing experiments in the field. Relatively, the low-mass WIMPs region (
$$\sim $$
10 MeV/c
$$^2$$
–10 GeV/c
$$^2$$
) has not been fully exploited compared to high-mass WIMPs (
$$\sim $$
10 GeV/c
$$^2$$
–10 TeV/c
$$^2$$
). The ALETHEIA (A Liquid hElium Time projection cHambEr In dArk matter) experiment aims to hunt for low-mass WIMPs with liquid helium-filled TPCs (time projection chambers). In this paper, we go through the physics motivation of the project, the detector’s design, the R &D plan, and the progress we have made since the project has been launched in the summer of 2020.
摘要：
The separation and enrichment of uranium from uranium containing wastewater is important for the sustainable development of nuclear energy. Therefore, there is an urgent need to develop a low-cost, readily available, simple preparation process and environmentally friendly adsorbent. In this study, potassium manganese ferro-cyanide and carbon nanotube encapsulated calcium alginate beads (KMnFC/CNT@SA) for uranium adsorption was prepared by a simple method using the inexpensive natural polymer material sodium alginate and the ion exchange material potassium manganese ferricyanide as well as carbon nanotubes capable of enhancing the spatial structure. Static adsorption experiments show that the adsorption capacity of KMnFC/CNT@SA for uranium is significantly affected by pH, contact time, U(VI) concentration and temperature, but is not affected by sodium ion concentration in solution. Furthermore, desorption and cycling tests demonstrate that KMnFC/ CNT@SA has good reusability, with the adsorption capacity remaining above 89.83% of the maximum adsorption capacity after 10 adsorption-desorption cycles. It is worth noting that KMnFC/CNT@SA can adsorb uranium well under acidic conditions, and is easy to solid-liquid separation and recovery. This work provides an effective strategy for the development of high-quality, inexpensive, practical and durable adsorbents for uranium extraction from acidic uranium-containing wastewater.
摘要：
It is crucial to correctly predict the S-matrix with plasma and set the optimal impedance matching device in the ion cyclotron resonance heating (ICRH) antenna system design. In this paper, a hybrid circuit/3DLHDAP code to verify the S-matrix measurements in the presence of plasma and optimize the load-resilient conjugate-T circuit for Large Helical Device (LHD) ICRH antennas has been developed and benchmarked. The variation of S-matrices for handshake form (HAS) and field-aligned-impedance-transforming (FAIT) antenna systems with density, magnetic field and coupling distance during heating obtained by the code's simulations agrees with that of with the LHD ICRH experiments. The mutual coupling of toroidally aligned HAS antennas is larger than that of poloidally aligned FAIT antennas over a wide range of densities. When the density and coupling distance increase, under a magnetic field on the magnetic axis of 2.75 T and 1.0 T, within a certain density change range, at the minimum voltage position with vacuum injection, the change rule of the antennas' S-a_minV_ 11 and S-a_minV_ 22 with density is opposite to that with coupling distance, which means that under certain conditions, adjusting the coupling distance may make up for the S-parameters changes caused by plasma density variation, keeping the minimum voltage position fixed, and may make impedance matching easier to achieve during long-pulse operation. Based on obtaining the S parameters, conjugate-T circuits for the HAS and FAIT antennas are designed with the hybrid circuit/3DLHDAP code, which can keep the reflection coefficients low without controlling impedance matching device over a wide range of plasma parameters region. The related results in this paper may provide some guidance for the high-power long-pulse operation of the ICRH antenna system on the fusion device.
摘要：
The treatment of hazardous LCD is a complicated coupled process, which contains a large number of impurity metals, especially Fe(III), increased the difficulty of In(III) recovery. Moreover, the defects of the traditional extraction process, such as extractant ageing quickly, difficulty to back-extraction, and easy emulsification, seriously restricted the efficient and environmentally friendly recovery of In. Therefore, a novel adsorbent (D2EHPA/SiO2–P) was synthesized for the separation and recovery of In(III), and a new recovery process was developed to eliminate the defects of traditional In recovery process in this study. D2EHPA/SiO2–P exhibited excellent adsorption selectivity and kinetics for In(III), and the adsorption equilibrium was obtained within 3 min. The adsorption process of In(III) conformed to the pseudo-second-order and Langmuir model. In(III) on D2EHPA/SiO2–P was desorbed by 3 M HCl solution, and D2EHPA/SiO2–P still had high adsorption and desorption efficiency for In(III) after 5 times of adsorption-desorption cycle experiments. The adsorption mechanism study found that the O–H bond on the D2EHPA participated in the substitution reaction and bonded with In(III) as the adsorption site during the adsorption process. The bond order value of In–O bond was the lowest in the D2EHPA adsorbed In(III) during the desorption process, indicating that In–O bond was easy to break and desorption form D2EHPA. Finally, in the 0.1M H2SO4 system, a new process of using H2C2O4 to reduce Fe(III) in advance, and then using D2EHPA/SiO2–P to adsorb In(III) was designed to recover In(III) without producing toxic gas, which realized the separation of In(III) and Fe(III). Our findings showed that the developed recovery process was both efficient and environmentally friendly, which had the potential for industrial application of In recovery from hazardous LCD.
摘要：
In this investigation, to separate and recover indium (In), the adsorption and desorption characteristics of indium in the sulfite-sulfuric acid system using IRA-900 resin and the adsorption mechanism were explored. When so-dium sulfite and sulfuric acid concentrations were 0.5 mol/L, IRA-900 resin exhibited the best adsorption selectivity to indium, with an adsorption capacity of 95.56 mg/g(318 K), while the adsorption capacities of Al, Sr, Fe, Zn and Cu were weak. In(III) adsorption by resin conforms to the second-order kinetic model, and the Langmuir model is more suitable for adsorption. In desorption experiments, 2 mol/L hydrochloric acid was selected as the desorption agent, with a desorption rate of 82.39 %. FT-IR (Fourier-transform infrared spec-troscopy), SEM-EDS (Scanning electron microscopy with energy dispersive spectroscopy), XPS (X-ray photo-electron spectroscopy) and elemental analysis results indicated that the adsorption mechanism of indium could be attributed to the formation of an anionic complex between In3+ and HSO3-/HSO4-, which could be exchanged with Cl- on the resin to adsorb the metal ions. In addition, the column experiment could efficiently separate indium from simulated indium-containing solution. In(III) recovery yield was about 99.6%, indicating its effective separation and recovery from ITO (Indium tin oxide) film.
通讯机构：
[Yu-Gang Ma] K;[Hong-Wei Wang] S;Key Laboratory of Nuclear Physics and Ion-beam Application (MOE), Institute of Modern Physics, Fudan University, Shanghai, China<&wdkj&>Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, China<&wdkj&>Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, China<&wdkj&>University of Chinese Academy of Science, Beijing, China
摘要：
The Shanghai laser electron gamma source (SLEGS) is a powerful tool for exploring photonuclear physics, such as giant dipole resonance (GDR) and pygmy dipole resonance, which are the main mechanisms of collective nuclear motion. The goal of the SLEGS neutron time-of-flight (TOF) spectrometer is to measure GDR and specific nuclear structures in the energy region above the neutron threshold. The SLEGS TOF spectrometer was designed to hold 20 sets of EJ301 and
$${\hbox {LaBr}_{3}}$$
detectors. Geant4 was used to simulate the efficiency of each detector and the entire spectrometer, which provides a reference for the selection of detectors and layout of the SLEGS TOF spectrometer. Under the events of
$$^{208}\hbox {Pb}$$
, implementations of coincidence and time-of-flight technology for complex experiments are available; thus,
$$\gamma $$
and neutron decay events can be separated. The performance of SLEGS TOF spectrometer was systematically evaluated using offline experiments, in which the time resolution reached approximately 0.9ns.
通讯机构：
[Yan, XQ ] P;Peking Univ, State Key Lab Nucl Phys & Technol, Beijing 100871, Peoples R China.;Peking Univ, Key Lab HEDP, CAPT, Minist Educ, Beijing 100871, Peoples R China.
关键词：
Photonuclear reactions;Laser-plasma acceleration;Flux-averaged isomer ratio
摘要：
In this study, we theoretically investigate the feasibility of using laser-wakefield accelerated (LWFA) electrons for the photonuclear measurement of nuclear isomers according to the characteristics of the electrons obtained from LWFA experiments conducted at the Compact Laser–Plasma Accelerator (CLAPA) laboratory. The experiments at the CLAPA show that a stable electron beam with an energy of 78–135 MeV and a charge of 300–600 pC can be obtained. The bremsstrahlung spectra were simulated using Geant4, which suggests that a bremsstrahlung source with a peak intensity of 10
$$^{19}$$
photons/s can be generated. Theoretical calculations of isomer production cross sections from the photonuclear reactions on six target nuclei,
$$^{197}$$
Au,
$$^{180}$$
Hf,
$$^{159}$$
Tb,
$$^{115}$$
In,
$$^{103}$$
Rh, and
$$^{90}$$
Zr, were performed and compared with the available experimental data in EXFOR, which suggest that further experiments are required for a series of photonuclear reaction channels. Flux-averaged cross sections and isomer ratios (IR) resulting from such bremsstrahlung sources are theoretically deduced. The results suggest that IR measurements can be used to constrain nuclear components, such as
$$\gamma$$
strength function and optical model potential. In addition, the detection of the decay characteristics was evaluated with Geant4 simulations. The use of the LWFA electron beam and its bremsstrahlung for photonuclear studies involving nuclear isomers is anticipated.
摘要：
Fine and dense LDH nanosheets firstly form on the Zn‐rich area of Zn–55Al. LDH can inhibit the cracking of corrosion product film and effectively improve the corrosion resistance of Zn–55Al. Abstract ZnAl layered double hydroxides (Zn6Al2(OH)16CO3, LDH) are the unique phase in the corrosion products of Zn–Al coating compared with the corrosion products of pure Zn coating. The effect of LDH on the corrosion resistance of Zn–55Al coating is investigated in this work. The LDH preferentially grows on the Zn‐rich region of Zn–55Al alloy, and then gradually grows on the Al‐rich region. The prepared LDH film can effectively inhibit the formation of simonkolleite (Zn5(OH)8Cl2, ZHC), hydrozincite (Zn5(CO3)2(OH)6, HZ), and ZnO in the corrosion product film of Zn–55Al alloy, making the corrosion product film more dense and less prone to cracking, which can effectively prevent the corrosion of Zn–55Al alloy. The LDH film can effectively reduce the corrosion current density and improve the electrochemical impedance of pure Zn. In the end, the corrosion protection mechanism of LDH on the surface of Zn–55Al alloy was discussed.
通讯机构：
[Hong Wang] S;School of Resources, Environmental and Safety Engineering, University of South China, Hengyang, China<&wdkj&>School of Nuclear Science and Technology, University of South China, Hengyang, China<&wdkj&>Hunan Province Engineering Technology Research Center of Uranium Tailings Treatment, University of South China, Hengyang, China
关键词：
Radiation protection;Radon adsorption;Biochar;Pore structure;Scanning electron microscopy
摘要：
Rice husk, grapefruit peel and sugarcane waste residue were used as raw materials to prepare biochar. The radon adsorption performance of biochar under dynamic radon exhalation environment was tested and the characterization of biochar was analyzed. The radon adsorption performance of PC600-D (rice husk biochar) and PC600-G (sugarcane bagasse biochar) was much better than that of PC600-Y (grapefruit peel biochar). The type of pore structure and the percentage of pore area had a greater influence on the biochar, and the honeycomb regular isolation structure of PC600-D and The regular honeycomb isolation structure of PC600-D and PC600-G helps to block the transport of radon, and the pore area ratios of PC600-D, PC600-G and PC600-Y are 61.01%, 82.66% and 29.36%, and the larger the pore area ratios are, the better the radon adsorption performance is. The process is mainly physical adsorption, and the elemental content has little influence on the radon adsorption characteristics.
摘要：
Radioactive strontium (90Sr) is widespreadly concerned due to its high biochemical toxicity, relatively long halflife, high fission yield and potential special applications in heat source and medical field. Herein, a novel acidresistant silica-based adsorbent Sb2O5/SiO2 was prepared by a two-step method, i.e. vacuum impregnation followed by oxidation. The adsorbent was characterized by XRD, SEM, TEM, EDS, BET, FT-IR and XPS techniques, which revealed its characterization of small particle size (75-150 & mu;m), abundant functional groups and well-crystallized structure. The experimental results revealed Sb2O5/SiO2 exhibited good adsorption selectivity for Sr in pH 9-3 M HNO3 solution, the adsorption equilibriums were obtained within 5 min in pH 6 solution and 30 min in 1 M HNO3 solution with the adsorption capacities of 160.6 mg/g and 51.8 mg/g, respectively. Moreover, it also demonstrated good application potential in medical isotope preparation area as efficient strontium-yttrium (Sr-Y) separation was achieved with the separation factor over 7769 in pH 6 solution. Furthermore, the column experiments confirmed that Sr could be effectively removed both in seawater and simulated high level liquid waste (HLLW), and the purity of Y could reach to 99.7 % in Sr-Y separation. Finally, density functional theory (DFT) calculations confirmed that the adsorption mechanism was ion exchange between Sr(II) and H+ (in Sb-OH), and the adsorption was accompanied by the transfer of charge and the decrease of adsorption energy.
摘要：
In this work, the effect of a magnetic island on Alfvén waves is studied. A physical model is established wherein Alfvén waves propagate in the presence of a magnetic island in a cylindrical geometry. The structure of the Alfvén wave continuum is calculated by considering only the coupling caused by the periodicity in the helical angle of the magnetic island. The results show that the magnetic island can induce an upshift in the Alfvén continuum. Moreover, the coupling between different branches of the continuous spectrum becomes more significant with increasing continuum mode numbers near the boundary of the magnetic island.
