Soil environment on earth contains a variety of ions,which are expected to play a vital role in the biodegradation of plastics discarded in the environment.In this work,poly(butyleneadipate-co-terephthalate)(PBAT)is e...Soil environment on earth contains a variety of ions,which are expected to play a vital role in the biodegradation of plastics discarded in the environment.In this work,poly(butyleneadipate-co-terephthalate)(PBAT)is employed as a model biodegradable plastic to study the specific ion effects on the enzymatic degradation of polyester plastics.The results show that the specific ion effects on the enzymatic degradation rate of the PBAT films and on the catalytic rate constant for the enzymatic hydrolysis of the ester bonds are strongly dependent on temperature and ionic strength.Both the enzymatic degradation rate and catalytic rate constant decrease following the trends Na^(+)>K^(+)>Ca^(2+)and Cl^(-)>SO_(4)^(2-)>NO_(3)^(-)for cations and anions,respectively,indicating that the ion-specific enzymatic degradation of the PBAT films is closely correlated with the specific ion effects on enzymatic hydrolysis of the ester bonds.Our study shows that the specific ion effects on the enzyme activity can be understood by taking into account the ion-specific cation-anion interaction,ionic dispersion force,salting-out effect and salting-in effect.This study of specific ion effects on the enzymatic hydrolysis of the ester bonds and the resultant enzymatic degradation of the PBAT films would offer us a new clue to develop new biodegradable,environmentally friendly synthetic plastics.展开更多
The process of adsorption of Cu^2+ Cd^2+ by immobilized marine algae was investigated, it can be noted from the results that, the process for biosorption of heavy metals (copper, cadmium) by immobilized Laminaria japo...The process of adsorption of Cu^2+ Cd^2+ by immobilized marine algae was investigated, it can be noted from the results that, the process for biosorption of heavy metals (copper, cadmium) by immobilized Laminaria japonica can be described by the Banerm model. According to the model, the adsorption rate constant calculated was 0.107 8 and 0.030 28 min^-1 for Cu^2+ and Cd^2+ respectively. The experimental biosorption equilibrium data for Cu^2+ and Cd^2+ were in good agreement with those calculated by the Langmuir model. The maximum uptake capacity calculated was 83.3 and 112.4 mg/g for Cu^2+ and Cd^2+ according to the Langmuir model, respectively. The appetency of Laminaria japonica to Cu^2+ was better than Cd^2+.展开更多
The ion saturation current is very important in probe theory, which can be used to measure the electron temperature and the floating potential. In this work, the effects of energetic ions on the ion saturation current...The ion saturation current is very important in probe theory, which can be used to measure the electron temperature and the floating potential. In this work, the effects of energetic ions on the ion saturation current are studied via particle-in-cell simulations. It is found that the energetic ions and background ions can be treated separately as different species, and they satisfy their individual Bohm criterion at the sheath edge. It is shown that the energetic ions can significantly affect the ion saturation current if their concentration is greater than root T-e/(gamma T-i2(i2)), where T-e is the electron temperature, and gamma(i2) and T-i2 represent the polytropic coefficient and temperature of energetic ions, respectively. As a result, the floating potential and the I-V characteristic profile are strongly influenced by the energetic ions. When the energetic ion current dominates the ion saturation current, an analysis of the ion saturation current will yield the energetic ion temperature rather than the electron temperature.展开更多
Graphene and thin graphite films deposited on SiO2/Si are irradiated by swift heavy ions(209Bi, 9.5 Me V/u) with the fluences in a range of 1011ions/cm2–1012ions/cm2 at room temperature. Both pristine and irradiated ...Graphene and thin graphite films deposited on SiO2/Si are irradiated by swift heavy ions(209Bi, 9.5 Me V/u) with the fluences in a range of 1011ions/cm2–1012ions/cm2 at room temperature. Both pristine and irradiated samples are investigated by Raman spectroscopy. For pristine graphite films, the 'blue shift' of 2D bond and the 'red shift' of G bond with the decrease of thickness are found in the Raman spectra. For both irradiated graphene and thin graphite films, the disorder-induced D peak and D' peak are detected at the fluence above a threshold Φth. The thinner the film, the lower the Φthis. In this work, the graphite films thicker than 60 nm reveal defect free via the absence of a D bond signal under the swift heavy ion irradiation till the fluence of 2.6 × 1012ions/cm2. For graphite films thinner than 6 nm, the area ratios between D peak and G peak increase sharply with reducing film thickness. It concludes that it is much easier to induce defects in thinner films than in thicker ones by swift heavy ions. The intensities of the D peak and D' peak increase with increasing ion fluence, which predicts the continuous impacting of swift heavy ions can lead to the increasing of defects in samples. Different defect types are detected in graphite films of different thickness values. The main defect types are discussed via the various intensity ratios between the D peak and D' peak(HD/HD).展开更多
Implantations of 100 keV In ions to high dose of 6 ×1016 In/cm2 were performed into a-axis oriented crystals of Al2O3 held at a liquid nitrogen temperature. The implantation produced about 80nm thick amorphous su...Implantations of 100 keV In ions to high dose of 6 ×1016 In/cm2 were performed into a-axis oriented crystals of Al2O3 held at a liquid nitrogen temperature. The implantation produced about 80nm thick amorphous surface layer. Isothermal annealing in flowing Ar gas ambient was done at the temperatures of 600, 700, 800, and 900℃ . Rutherford backscattering and channeling (RBS-C), scanning electron microscope (SEM) and reflection high energy electron diffraction (RHEED) have been employed to investigate the annealing behaviors.The indium shows anomalous diffusion in amorphous layer. The migration of indium was composed of two parts: (a) some broadening of In profile corresponding to diffusion within the amorphous layer, (b) segregation of In to surface to form In2O3 which appears as islands on the surface. When the ambient is made oxygen free, the segregated In is lost by evaporation at the surface.展开更多
In this work, top and back gate characteristics of partially-depleted NMOS transistors with enclosed gate fabricated on SIMOX which is hardened by silicon ions implantation were studied under X-ray total-dose irradiat...In this work, top and back gate characteristics of partially-depleted NMOS transistors with enclosed gate fabricated on SIMOX which is hardened by silicon ions implantation were studied under X-ray total-dose irradiation of three bias conditions. It has been found experimentally that back gate threshold shift and leakage current were greatly reduced during irradiation for hardened transistors, comparing to control ones. It has been confirmed that the improvement of total-dose properties of SOI devices is attributed to the silicon nanocrystals (nanoclusters) in buried oxides introduced by ion implantation.展开更多
Y1.6Ca1.4V 0.45Sn0.5Fe4.05O12 is irradiated by 0.56 GeV carbon ion. The irradiation effect is investigated by Mossbauer spectroscopy. The irradiation results in an isotropic distribution of the hyperfine magnetic fiel...Y1.6Ca1.4V 0.45Sn0.5Fe4.05O12 is irradiated by 0.56 GeV carbon ion. The irradiation effect is investigated by Mossbauer spectroscopy. The irradiation results in an isotropic distribution of the hyperfine magnetic field. The hyperfine magnetic fields decrease after the irradiation due to the change of supertransferred field. After the irradiation, the chain Fe(a)-oxygen-Fe(d) become longer and it leads to decrease of the supertransferred field.展开更多
The contribution of parasitic bipolar amplification to SETs is experimentally verified using two P-hit target chains in the normal layout and in the special layout. For PMOSs in the normal layout, the single-event cha...The contribution of parasitic bipolar amplification to SETs is experimentally verified using two P-hit target chains in the normal layout and in the special layout. For PMOSs in the normal layout, the single-event charge collection is composed of diffusion, drift, and the parasitic bipolar effect, while for PMOSs in the special layout, the parasitic bipolar junction transistor cannot turn on. Heavy ion experimental results show that PMOSs without parasitic bipolar amplification have a 21.4% decrease in the average SET pulse width and roughly a 40.2% reduction in the SET cross-section.展开更多
The effect of the anion in the original rare earth element（REE） solution on the reversible ion exchange of Ce nitrate and Ce sulfate with the Dowex 50 W X8 was investigated using attenuated total reflection infrared...The effect of the anion in the original rare earth element（REE） solution on the reversible ion exchange of Ce nitrate and Ce sulfate with the Dowex 50 W X8 was investigated using attenuated total reflection infrared（ATR-IR） spectroscopy, continuous flow reactor studies coupled with inductively coupled plasma mass spectroscopy（ICP-MS）, and density functional theory（DFT）. The simulated IR spectrum at the DFT B3 LYP/6-31 G（d） level was compared to the experimental results to characterize the IR spectrum, molecular interactions, and bonding of the ion exchanged species. The continuous liquid flow reactor studies show a capacity of 0.72 mmol/g sorbent for the Ce nitrateand 0.96 mmol/g sorbent for the Ce sulfate with the Dowex 50 W X8. The flow reactor studies reveal the type of solute anion（SO_4^（（2-）） or NO_3^（（-））） associated with the REE during cation exchange significantly affects the sorption capacity of the Dowex 50 W X8 ion exchange resin. The calculated REE binding energy（BE） and the DFT optimized structures suggest that the differences in sorption capacity is the result of the formation of different types of partially ionexchanged Ce_2^（（3＋））2 SO_4^（（2-）） and Ce^（（3＋）） 3 NO_3^（（-））. These results suggest that the solute anion affects the equilibrium constants of the Dowex resin by the formation of a charged layer capable of retaining the counterion. Modifying the sulfonic acid site（H＋） in the Dowex 50 W X8 with the NH_4~＋ counterion does not affect the sorption capacity and retention times of the Ce nitrate and Ce sulfate species. These results suggest that the counterions and co-ions having a finite size, may limit access to the Dowex sulfonate active site where the type of REE cation as a nitrate or sulfate in solution may significantly modify the sorption capacity of the ion exchange resin. Similar results are obtained during sorption with nitrates and sulfates of Sm and Yb.展开更多
The morphology manipulation of nanomaterials by ion irradiation builds a way to precisely control physicochemical properties.Under the continuous irradiation of low energy Ga+,Ne+,and He+ions,an ion compaction effect ...The morphology manipulation of nanomaterials by ion irradiation builds a way to precisely control physicochemical properties.Under the continuous irradiation of low energy Ga+,Ne+,and He+ions,an ion compaction effect has been found in hollow FePt nanochains with ultrathin shell that the volumes of the nanochains are gradually compacted by ions.The deep learning algorithm has been successfully applied to automatically and precisely measure average sizes of spheres in hollow FePt nanochains.The compaction under ion irradiation is very fast in the very early period and then proceeds to a slow region.The compaction rates in both regions are linearly fitted and all the values are in the order of 10^(–17) to 10^(–14) cm^(2)/ion.Ion species and ion current have effect on the compaction rate.For example,the compaction rate of Ga+ions is larger than those of Ne+and He+ions under an identical current,while irradiation with larger current can compact nanochains faster.The ion compaction effect originates from the local shear deformation caused by the interaction between incident ions and the electrons of Fe and Pt atoms in the ultrathin shell.With continuous irradiation,the crystalline clusters of FePt nanchains firstly grow larger and then become amorphous.The ion compaction effect can be applied to tune the size and crystal structure of hollow structures with a precise rate by choosing appropriate ion species and current.展开更多
In this work,for the first time,it is demonstrated that during the insertion/extraction of Na ions,the structural evolution at the Na_(4)site at a voltage range of 3-4 V is a key factor for the capacity decay of Na_(4...In this work,for the first time,it is demonstrated that during the insertion/extraction of Na ions,the structural evolution at the Na_(4)site at a voltage range of 3-4 V is a key factor for the capacity decay of Na_(4)Fe_(3)(PO_(4))_(2)P_(2)O_(7)(NFPP).Herein,a strategy of introducing columnar potassium ions at the Na_(4)site is proposed to address the aforementioned challenge.As a cathode material for sodium-ion batteries,the K_(0.12)Na_(3.88)Fe_(3)(PO_(4))_(2)P_(2)O_(7)/C(K-NFPP)composite enhances the reversibility of Na_(4)extraction.Specifically,the K-NFPP exhibits an initial discharge capacity of 107.8 mAh g^(-1)at a high current density of 5 C,with a capacity retention of 91.4% after 2000 cycles,outperforming the pristine NFPP material(81.1 m Ah g^(-1)and 67.1%).At 5 C,the K-NFPP also retains 81.5% of the reversible capacity at 0.1 C,whereas the NFPP only retains 68.3%.Moreover,the K-NFPP-based full-cell delivers an initial capacity of 110.1 m Ah g^(-1)at 1 C,with a capacity retention of 90% after 100 cycles.It is found that in comparison to K-doping of the Na1,Na2,and Na3 sites,K-doping at the Na4 site effectively optimizes the band gap and stabilizes the crystal structure,thereby reducing lattice changes of FeO_(6)evolution during Na^(+)insertion/extraction.As a result,the introduction of columnar potassium ions significantly enhances the capacity contribution of the Na_(4)site,optimizes reaction kinetics,and effectively mitigates the capacity decay of NFPP cathodes.It is believed that this study offers a new entry point for the application of NFPP in high-voltage sodium storage.展开更多
To understand the effect of precipitation pH and coexisting Mg^(2+) on phosphate adsorption onto zirconium oxide(ZrO_2), ZrO_2 particles precipitated at pH 5.3, 7.1 and 10.5, i.e., ZrO_2(5.3), ZrO_2(7.1)and ZrO_2(10.5...To understand the effect of precipitation pH and coexisting Mg^(2+) on phosphate adsorption onto zirconium oxide(ZrO_2), ZrO_2 particles precipitated at pH 5.3, 7.1 and 10.5, i.e., ZrO_2(5.3), ZrO_2(7.1)and ZrO_2(10.5), respectively were prepared and characterized, then their adsorption performance and mechanism in the absence and presence of Mg^(2+) were comparatively investigated in this study. The results showed that the Elovich, pseudo-second-order and Langmuir isotherm models correlated with the experimental data well. The adsorption mechanism involved the complexation between phosphate and zirconium. Coexisting Mg^(2+) slightly inhibited the adsorption of phosphate on ZrO_2(5.3), including the adsorption capacity and rate, but coexisting Mg^(2+) greatly increased the adsorption capacity and rate for ZrO_2(7.1)and ZrO_2(10.5). The enhanced adsorption of phosphate on ZrO_2(7.1) and ZrO_2(10.5) in the presence of Mg^(2+) was mainly due to the formation of Mg^(2+)-HPO_4^(2-) ion pair(MgHPO_4~0) in the solution and then the adsorption of MgHPO_4~0 on the adsorbent surface, forming the phosphatebridged ternary complex Zr(OPO_3H)Mg. In the absence of Mg^(2+) , the maximum phosphate adsorption capacity at pH 7 calculated from the Langmuir isotherm model decreased in the order of ZrO 2(7.1)(67.3 mg/g) > ZrO_2(5.3)(53.6 mg/g) ≈ ZrO_2(10.5)(53.1 mg/g), but it followed the order of Zr O2(7.1)(97.0 mg/g) > ZrO_2(10.5)(79.7 mg/g) > ZrO_2(5.3)(51.3 mg/g) in the presence of Mg^(2+) . The results of this work suggest that ZrO_2(7.1) is more suitable for use as an adsorbent for the effective removal of phosphate from municipal wastewater than ZrO_2(5.3) and ZrO_2(10.5),because Mg^(2+) is generally present in this wastewater.展开更多
The bond length of ^4HeH^＋ resulting from collision-induced destruction is measured at 1.4420 MeV using the Coulomb Explosion Technique. The measured bond length of ^4HeH^＋ is 0.094±0.003nm. The bond length of ...The bond length of ^4HeH^＋ resulting from collision-induced destruction is measured at 1.4420 MeV using the Coulomb Explosion Technique. The measured bond length of ^4HeH^＋ is 0.094±0.003nm. The bond length of ^4HeH^＋ obtained with our radio frequency （RF） ion source is larger than that obtained with a duoplasmatron ion source at Argonne National Laboratory （ANL）, but the bond lengths of H^＋2 and H^＋3obtained separately by ANL and by us with the two different ion sources are consistent with each other, which implies that there exists an ion source effect on the bond length of ^4HeH^＋. The main reason why the 4^4HeH^＋ bond lengths obtained by the two different ion sources are different is also discussed.展开更多
Free radical polymerization and living ion polymerization have been simulated via the dynamic Monte Carlo method with the bond-fluctuation model in this paper. The polymeriza-tion-related parameters such as conversion...Free radical polymerization and living ion polymerization have been simulated via the dynamic Monte Carlo method with the bond-fluctuation model in this paper. The polymeriza-tion-related parameters such as conversion of monomers, degree of polymerization, average molecular weight and its distribution are obtained by statistics. The simulation outputs are con-sistent with the corresponding theoretical predictions. The scaling relationships of the coil size versus chain length are also confirmed at different volume fractions. Furthermore, the effect of diffusion on polymerization is revealed preliminarily in our simulation. Hence the simulation ap-proach has been proven to be feasible to investigate polymerization reactions with the advan-tages that configuration and diffusion of polymer chains can be examined together with polym-erization kinetics.展开更多
Porous FeS nanofibers with numerous nanovoids for use as anode materials for sodium-ion batteries were prepared by electrospinning and subsequent sulfidation. The post-treatment of the as-spun Fe（acac）3-polyacryloni...Porous FeS nanofibers with numerous nanovoids for use as anode materials for sodium-ion batteries were prepared by electrospinning and subsequent sulfidation. The post-treatment of the as-spun Fe（acac）3-polyacrylonitrile composite nanofibers in an air atmosphere yielded hollow Fe2O3 nanofibers due to Ostwald ripening. The ultrafine Fe2O3 nanocrystals formed at the center of the fiber diffused toward the outside of the fiber via Ostwald ripening. On sulfidation, the Fe2O3 hollow nanofibers were transformed into porous FeS nanofibers, which contained numerous nanovoids. The formation of porosity in the FeS nanofibers was driven by nanoscale Kirkendall diffusion. The porous FeS nanofibers were very structurally stable and had superior sodium-ion storage properties compared with the hollow Fe2O3 nanofibers. The discharge capacities of the porous FeS nanofibers for the Ist and 150th cycles at a current density of 500 mA.g-1 were 561 and 592 mA.h-g-1, respectively. The FeS nanofibers had final discharge capacities of 456, 437, 413, 394, 380, and 353 mA-h.g-1 at current densities of 0.2, 0.5, 1.0, 2.0, 3.0, and 5.0 A.g-1, respectively.展开更多
Superoxide dismutase（SOD） is a crucial antioxidant enzyme playing the first defense line in antioxidant pathways against reactive oxygen species in various organisms including marine invertebrates. There exist mainl...Superoxide dismutase（SOD） is a crucial antioxidant enzyme playing the first defense line in antioxidant pathways against reactive oxygen species in various organisms including marine invertebrates. There exist mainly two specific forms, Cu/Zn-SOD（SOD1） and Mn-SOD（SOD2）, in eukaryotes. SODs are known to be concurrently modulated by a variety of environmental stressors. By using central composite experimental design and response surface method, the joint effects of water temperature（18–34°C） and copper ion concentration（0.1–1.5 mg/L） on the total SOD activity in the digestive gland of Crassostrea ariakensis were studied. The results showed that the linear effect of temperature was highly significant（P〈0.01）, the quadratic effect of temperature was significant（P〈0.05）; the linear effect of copper ion concentration was not significant（P〉0.05）, while the quadratic effect of copper ion concentration was highly significant（P〈0.01）; the interactive effect of temperature and copper ion concentration was not significant（P〉0.05）; the effect of temperature was greater than that of copper ion concentration. The model equation of digestive gland SOD enzyme activity towards the two factors of interest was established, with R2 and predictive R2 as high as 0.961 6 and 0.820 7, respectively, suggesting that the goodness-offit to experimental data be very satisfactory, and could be applied to prediction of digestive gland SOD activity in C. ariakensis under the conditions of the experiment. Our results would be conducive to addressing the health of aquatic animals and/or to detecting environmental problems by taking SOD as a potential bioindicator.展开更多
Copper-exchanged chabazite（Cu/CHA） catalysts have been found to be affected by alkali metal and alkaline earth ions. However, the effects of Na＋ ions on Cu/SAPO-34 for ammonia selective catalytic reduction（NH_3-SC...Copper-exchanged chabazite（Cu/CHA） catalysts have been found to be affected by alkali metal and alkaline earth ions. However, the effects of Na＋ ions on Cu/SAPO-34 for ammonia selective catalytic reduction（NH_3-SCR） are still unclear. In order to investigate the mechanism, five samples with various Na contents were synthesized and characterized. It was observed that the introduced Na＋ ion-exchanges with H＋and Cu2＋of Cu/SAPO-34. The exchange of H＋is easier than that of isolated Cu2＋. The exchanged Cu2＋ions aggregate and form ＂CuAl_2O4-like＂ species.The NH_3-SCR activity of Cu/SAPO-34 decreases with increasing Na content, and the loss of isolated Cu2＋and acid sites is responsible for the activity loss.展开更多
We use the extended gate field effect transistor (EGFET)as the structure of the chlorine ion sensor,and the chlorine ion ionophores (ETH9033 and TDDMAC1)are incorporated into solvent polymeric membrane (PVC/DOS),then ...We use the extended gate field effect transistor (EGFET)as the structure of the chlorine ion sensor,and the chlorine ion ionophores (ETH9033 and TDDMAC1)are incorporated into solvent polymeric membrane (PVC/DOS),then the chlorine ion selective membrane is formed on the sensing window,and the fabrication of the EGFET chlorine ion sensing device is completed.The surface potential on the sensing membrane of the EGFET chlorine ion sensing device will be changed in the different chlorine ion concentration solutions,then changes further gate voltage and drain current to detect chlorine ion concentration.We will study non-ideal effects such as temperature,hysteresis and drift effects for the EGFET chlorine ion sensing device in this paper,these researches will help us to improve the sensing characteristics of the EGFET chlorine ion sensing device.展开更多
To explore the survival and dose response of organism for different radiation sources is of great importance in the research of radiobiology. In this study, the survival-dose response of Deinococcus radiodurans (E.col...To explore the survival and dose response of organism for different radiation sources is of great importance in the research of radiobiology. In this study, the survival-dose response of Deinococcus radiodurans (E.coli, as the control) for ultra-violet (UV), γ-rays radiation and ion beam exposure was investigated. The shoulder type of survival curves were found for both UV and γ-ray ionizing radiation, but the saddle type of survival curves were shown for H+、 N+( 20keV and 30keV) and Ar+ beam exposure. This dose effect of the survival initially decreased with the increase in dose and then increased in the high dose range and finally decreased again in the higher dose range. Our experimental results suggest that D. radiodurans, which is considerably radio-resistant to UV and x-ray and γ-ray ionizing radiation, do not resist ion beam exposure.展开更多
基金the National Natural Science Foundation of China(Nos.21873091,52033001 and 22103002)the Youth Innovation Promotion Association of CAS(No.Y201769)+1 种基金the National Synchrotron Radiation Laboratory(No.UN2018LHJJ)the Fundamental Research Funds for the Central Universities(No.WK2480000007).
文摘Soil environment on earth contains a variety of ions,which are expected to play a vital role in the biodegradation of plastics discarded in the environment.In this work,poly(butyleneadipate-co-terephthalate)(PBAT)is employed as a model biodegradable plastic to study the specific ion effects on the enzymatic degradation of polyester plastics.The results show that the specific ion effects on the enzymatic degradation rate of the PBAT films and on the catalytic rate constant for the enzymatic hydrolysis of the ester bonds are strongly dependent on temperature and ionic strength.Both the enzymatic degradation rate and catalytic rate constant decrease following the trends Na^(+)>K^(+)>Ca^(2+)and Cl^(-)>SO_(4)^(2-)>NO_(3)^(-)for cations and anions,respectively,indicating that the ion-specific enzymatic degradation of the PBAT films is closely correlated with the specific ion effects on enzymatic hydrolysis of the ester bonds.Our study shows that the specific ion effects on the enzyme activity can be understood by taking into account the ion-specific cation-anion interaction,ionic dispersion force,salting-out effect and salting-in effect.This study of specific ion effects on the enzymatic hydrolysis of the ester bonds and the resultant enzymatic degradation of the PBAT films would offer us a new clue to develop new biodegradable,environmentally friendly synthetic plastics.
文摘The process of adsorption of Cu^2+ Cd^2+ by immobilized marine algae was investigated, it can be noted from the results that, the process for biosorption of heavy metals (copper, cadmium) by immobilized Laminaria japonica can be described by the Banerm model. According to the model, the adsorption rate constant calculated was 0.107 8 and 0.030 28 min^-1 for Cu^2+ and Cd^2+ respectively. The experimental biosorption equilibrium data for Cu^2+ and Cd^2+ were in good agreement with those calculated by the Langmuir model. The maximum uptake capacity calculated was 83.3 and 112.4 mg/g for Cu^2+ and Cd^2+ according to the Langmuir model, respectively. The appetency of Laminaria japonica to Cu^2+ was better than Cd^2+.
基金Supported by the Program of Fusion Reactor Physics and Digital Tokamak with the Chinese Academy of Sciences'One-Three Five'Strategic Planningthe JSPS-NRF-NSFC A3 Foresight Program in the Field of Plasma Physics(NSFC No 11261140328 and NRF No 2012K2A2A6000443)+1 种基金the National ITER Program of China under Grant No 2015GB101003the National Natural Science Foundation of China under Grant Nos 11405215,11475223 and 11505236
文摘The ion saturation current is very important in probe theory, which can be used to measure the electron temperature and the floating potential. In this work, the effects of energetic ions on the ion saturation current are studied via particle-in-cell simulations. It is found that the energetic ions and background ions can be treated separately as different species, and they satisfy their individual Bohm criterion at the sheath edge. It is shown that the energetic ions can significantly affect the ion saturation current if their concentration is greater than root T-e/(gamma T-i2(i2)), where T-e is the electron temperature, and gamma(i2) and T-i2 represent the polytropic coefficient and temperature of energetic ions, respectively. As a result, the floating potential and the I-V characteristic profile are strongly influenced by the energetic ions. When the energetic ion current dominates the ion saturation current, an analysis of the ion saturation current will yield the energetic ion temperature rather than the electron temperature.
基金supported by the National Natural Science Foundation of China(Grant Nos.11179003,10975164,10805062,11005134,and 11275237)
文摘Graphene and thin graphite films deposited on SiO2/Si are irradiated by swift heavy ions(209Bi, 9.5 Me V/u) with the fluences in a range of 1011ions/cm2–1012ions/cm2 at room temperature. Both pristine and irradiated samples are investigated by Raman spectroscopy. For pristine graphite films, the 'blue shift' of 2D bond and the 'red shift' of G bond with the decrease of thickness are found in the Raman spectra. For both irradiated graphene and thin graphite films, the disorder-induced D peak and D' peak are detected at the fluence above a threshold Φth. The thinner the film, the lower the Φthis. In this work, the graphite films thicker than 60 nm reveal defect free via the absence of a D bond signal under the swift heavy ion irradiation till the fluence of 2.6 × 1012ions/cm2. For graphite films thinner than 6 nm, the area ratios between D peak and G peak increase sharply with reducing film thickness. It concludes that it is much easier to induce defects in thinner films than in thicker ones by swift heavy ions. The intensities of the D peak and D' peak increase with increasing ion fluence, which predicts the continuous impacting of swift heavy ions can lead to the increasing of defects in samples. Different defect types are detected in graphite films of different thickness values. The main defect types are discussed via the various intensity ratios between the D peak and D' peak(HD/HD).
文摘Implantations of 100 keV In ions to high dose of 6 ×1016 In/cm2 were performed into a-axis oriented crystals of Al2O3 held at a liquid nitrogen temperature. The implantation produced about 80nm thick amorphous surface layer. Isothermal annealing in flowing Ar gas ambient was done at the temperatures of 600, 700, 800, and 900℃ . Rutherford backscattering and channeling (RBS-C), scanning electron microscope (SEM) and reflection high energy electron diffraction (RHEED) have been employed to investigate the annealing behaviors.The indium shows anomalous diffusion in amorphous layer. The migration of indium was composed of two parts: (a) some broadening of In profile corresponding to diffusion within the amorphous layer, (b) segregation of In to surface to form In2O3 which appears as islands on the surface. When the ambient is made oxygen free, the segregated In is lost by evaporation at the surface.
文摘In this work, top and back gate characteristics of partially-depleted NMOS transistors with enclosed gate fabricated on SIMOX which is hardened by silicon ions implantation were studied under X-ray total-dose irradiation of three bias conditions. It has been found experimentally that back gate threshold shift and leakage current were greatly reduced during irradiation for hardened transistors, comparing to control ones. It has been confirmed that the improvement of total-dose properties of SOI devices is attributed to the silicon nanocrystals (nanoclusters) in buried oxides introduced by ion implantation.
文摘Y1.6Ca1.4V 0.45Sn0.5Fe4.05O12 is irradiated by 0.56 GeV carbon ion. The irradiation effect is investigated by Mossbauer spectroscopy. The irradiation results in an isotropic distribution of the hyperfine magnetic field. The hyperfine magnetic fields decrease after the irradiation due to the change of supertransferred field. After the irradiation, the chain Fe(a)-oxygen-Fe(d) become longer and it leads to decrease of the supertransferred field.
基金supported by the National Natural Science Foundation of China(Grant No.61376109)
文摘The contribution of parasitic bipolar amplification to SETs is experimentally verified using two P-hit target chains in the normal layout and in the special layout. For PMOSs in the normal layout, the single-event charge collection is composed of diffusion, drift, and the parasitic bipolar effect, while for PMOSs in the special layout, the parasitic bipolar junction transistor cannot turn on. Heavy ion experimental results show that PMOSs without parasitic bipolar amplification have a 21.4% decrease in the average SET pulse width and roughly a 40.2% reduction in the SET cross-section.
基金Project supported by NETL's ongoing research under the Research&Engineering Services(RES)contract DE-FE0004000
文摘The effect of the anion in the original rare earth element（REE） solution on the reversible ion exchange of Ce nitrate and Ce sulfate with the Dowex 50 W X8 was investigated using attenuated total reflection infrared（ATR-IR） spectroscopy, continuous flow reactor studies coupled with inductively coupled plasma mass spectroscopy（ICP-MS）, and density functional theory（DFT）. The simulated IR spectrum at the DFT B3 LYP/6-31 G（d） level was compared to the experimental results to characterize the IR spectrum, molecular interactions, and bonding of the ion exchanged species. The continuous liquid flow reactor studies show a capacity of 0.72 mmol/g sorbent for the Ce nitrateand 0.96 mmol/g sorbent for the Ce sulfate with the Dowex 50 W X8. The flow reactor studies reveal the type of solute anion（SO_4^（（2-）） or NO_3^（（-））） associated with the REE during cation exchange significantly affects the sorption capacity of the Dowex 50 W X8 ion exchange resin. The calculated REE binding energy（BE） and the DFT optimized structures suggest that the differences in sorption capacity is the result of the formation of different types of partially ionexchanged Ce_2^（（3＋））2 SO_4^（（2-）） and Ce^（（3＋）） 3 NO_3^（（-））. These results suggest that the solute anion affects the equilibrium constants of the Dowex resin by the formation of a charged layer capable of retaining the counterion. Modifying the sulfonic acid site（H＋） in the Dowex 50 W X8 with the NH_4~＋ counterion does not affect the sorption capacity and retention times of the Ce nitrate and Ce sulfate species. These results suggest that the counterions and co-ions having a finite size, may limit access to the Dowex sulfonate active site where the type of REE cation as a nitrate or sulfate in solution may significantly modify the sorption capacity of the ion exchange resin. Similar results are obtained during sorption with nitrates and sulfates of Sm and Yb.
基金supported by the National Natural Science Foundation of China(No.52071009,52130103,51701202,and 12011530067)the Fundamental Research Funds for the Central Universities(No.ZY2211).
文摘The morphology manipulation of nanomaterials by ion irradiation builds a way to precisely control physicochemical properties.Under the continuous irradiation of low energy Ga+,Ne+,and He+ions,an ion compaction effect has been found in hollow FePt nanochains with ultrathin shell that the volumes of the nanochains are gradually compacted by ions.The deep learning algorithm has been successfully applied to automatically and precisely measure average sizes of spheres in hollow FePt nanochains.The compaction under ion irradiation is very fast in the very early period and then proceeds to a slow region.The compaction rates in both regions are linearly fitted and all the values are in the order of 10^(–17) to 10^(–14) cm^(2)/ion.Ion species and ion current have effect on the compaction rate.For example,the compaction rate of Ga+ions is larger than those of Ne+and He+ions under an identical current,while irradiation with larger current can compact nanochains faster.The ion compaction effect originates from the local shear deformation caused by the interaction between incident ions and the electrons of Fe and Pt atoms in the ultrathin shell.With continuous irradiation,the crystalline clusters of FePt nanchains firstly grow larger and then become amorphous.The ion compaction effect can be applied to tune the size and crystal structure of hollow structures with a precise rate by choosing appropriate ion species and current.
基金financial support from the National Natural Science Foundation of China(52272237,22279101 and 22172117)the Natural Science Foundation of Shaanxi(2020JC-41 and 2024JC-YBQN-0141)+2 种基金the Scientific Research Program Funded by the Education Department of Shaanxi Provincial Government(22JP056)the S&T Program of Energy Shaanxi Laboratory(ESLB202402)the Foshan Science and Technology Innovation Team Project(1920001004098)。
文摘In this work,for the first time,it is demonstrated that during the insertion/extraction of Na ions,the structural evolution at the Na_(4)site at a voltage range of 3-4 V is a key factor for the capacity decay of Na_(4)Fe_(3)(PO_(4))_(2)P_(2)O_(7)(NFPP).Herein,a strategy of introducing columnar potassium ions at the Na_(4)site is proposed to address the aforementioned challenge.As a cathode material for sodium-ion batteries,the K_(0.12)Na_(3.88)Fe_(3)(PO_(4))_(2)P_(2)O_(7)/C(K-NFPP)composite enhances the reversibility of Na_(4)extraction.Specifically,the K-NFPP exhibits an initial discharge capacity of 107.8 mAh g^(-1)at a high current density of 5 C,with a capacity retention of 91.4% after 2000 cycles,outperforming the pristine NFPP material(81.1 m Ah g^(-1)and 67.1%).At 5 C,the K-NFPP also retains 81.5% of the reversible capacity at 0.1 C,whereas the NFPP only retains 68.3%.Moreover,the K-NFPP-based full-cell delivers an initial capacity of 110.1 m Ah g^(-1)at 1 C,with a capacity retention of 90% after 100 cycles.It is found that in comparison to K-doping of the Na1,Na2,and Na3 sites,K-doping at the Na4 site effectively optimizes the band gap and stabilizes the crystal structure,thereby reducing lattice changes of FeO_(6)evolution during Na^(+)insertion/extraction.As a result,the introduction of columnar potassium ions significantly enhances the capacity contribution of the Na_(4)site,optimizes reaction kinetics,and effectively mitigates the capacity decay of NFPP cathodes.It is believed that this study offers a new entry point for the application of NFPP in high-voltage sodium storage.
基金supported by the Shanghai Natural Science Foundation (No.15ZR1420700)the National Science Foundation of China (Nos.51408354 and 50908142)the Scientific Research Project of Shanghai Science and Technology Committee (No.10230502900)
文摘To understand the effect of precipitation pH and coexisting Mg^(2+) on phosphate adsorption onto zirconium oxide(ZrO_2), ZrO_2 particles precipitated at pH 5.3, 7.1 and 10.5, i.e., ZrO_2(5.3), ZrO_2(7.1)and ZrO_2(10.5), respectively were prepared and characterized, then their adsorption performance and mechanism in the absence and presence of Mg^(2+) were comparatively investigated in this study. The results showed that the Elovich, pseudo-second-order and Langmuir isotherm models correlated with the experimental data well. The adsorption mechanism involved the complexation between phosphate and zirconium. Coexisting Mg^(2+) slightly inhibited the adsorption of phosphate on ZrO_2(5.3), including the adsorption capacity and rate, but coexisting Mg^(2+) greatly increased the adsorption capacity and rate for ZrO_2(7.1)and ZrO_2(10.5). The enhanced adsorption of phosphate on ZrO_2(7.1) and ZrO_2(10.5) in the presence of Mg^(2+) was mainly due to the formation of Mg^(2+)-HPO_4^(2-) ion pair(MgHPO_4~0) in the solution and then the adsorption of MgHPO_4~0 on the adsorbent surface, forming the phosphatebridged ternary complex Zr(OPO_3H)Mg. In the absence of Mg^(2+) , the maximum phosphate adsorption capacity at pH 7 calculated from the Langmuir isotherm model decreased in the order of ZrO 2(7.1)(67.3 mg/g) > ZrO_2(5.3)(53.6 mg/g) ≈ ZrO_2(10.5)(53.1 mg/g), but it followed the order of Zr O2(7.1)(97.0 mg/g) > ZrO_2(10.5)(79.7 mg/g) > ZrO_2(5.3)(51.3 mg/g) in the presence of Mg^(2+) . The results of this work suggest that ZrO_2(7.1) is more suitable for use as an adsorbent for the effective removal of phosphate from municipal wastewater than ZrO_2(5.3) and ZrO_2(10.5),because Mg^(2+) is generally present in this wastewater.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 10175041 and 10375040）.
文摘The bond length of ^4HeH^＋ resulting from collision-induced destruction is measured at 1.4420 MeV using the Coulomb Explosion Technique. The measured bond length of ^4HeH^＋ is 0.094±0.003nm. The bond length of ^4HeH^＋ obtained with our radio frequency （RF） ion source is larger than that obtained with a duoplasmatron ion source at Argonne National Laboratory （ANL）, but the bond lengths of H^＋2 and H^＋3obtained separately by ANL and by us with the two different ion sources are consistent with each other, which implies that there exists an ion source effect on the bond length of ^4HeH^＋. The main reason why the 4^4HeH^＋ bond lengths obtained by the two different ion sources are different is also discussed.
基金supported by the National Natural Science Foundation of China(Grant Nos.29825109,20174006,20221402,20374015,and Two-Base Grant)the Key Grant of Chinese Ministry of Education(Grant No.305004)+2 种基金the Award Foundation for Young Teachers from the Ministry of Education of China,973 Project(Grant No.G1999054306-03)863 Project(Grant No.2004AA215170)the Science and Technology Developing Foundation of Shanghai(Grant No.04JC14019).
文摘Free radical polymerization and living ion polymerization have been simulated via the dynamic Monte Carlo method with the bond-fluctuation model in this paper. The polymeriza-tion-related parameters such as conversion of monomers, degree of polymerization, average molecular weight and its distribution are obtained by statistics. The simulation outputs are con-sistent with the corresponding theoretical predictions. The scaling relationships of the coil size versus chain length are also confirmed at different volume fractions. Furthermore, the effect of diffusion on polymerization is revealed preliminarily in our simulation. Hence the simulation ap-proach has been proven to be feasible to investigate polymerization reactions with the advan-tages that configuration and diffusion of polymer chains can be examined together with polym-erization kinetics.
文摘Porous FeS nanofibers with numerous nanovoids for use as anode materials for sodium-ion batteries were prepared by electrospinning and subsequent sulfidation. The post-treatment of the as-spun Fe（acac）3-polyacrylonitrile composite nanofibers in an air atmosphere yielded hollow Fe2O3 nanofibers due to Ostwald ripening. The ultrafine Fe2O3 nanocrystals formed at the center of the fiber diffused toward the outside of the fiber via Ostwald ripening. On sulfidation, the Fe2O3 hollow nanofibers were transformed into porous FeS nanofibers, which contained numerous nanovoids. The formation of porosity in the FeS nanofibers was driven by nanoscale Kirkendall diffusion. The porous FeS nanofibers were very structurally stable and had superior sodium-ion storage properties compared with the hollow Fe2O3 nanofibers. The discharge capacities of the porous FeS nanofibers for the Ist and 150th cycles at a current density of 500 mA.g-1 were 561 and 592 mA.h-g-1, respectively. The FeS nanofibers had final discharge capacities of 456, 437, 413, 394, 380, and 353 mA-h.g-1 at current densities of 0.2, 0.5, 1.0, 2.0, 3.0, and 5.0 A.g-1, respectively.
基金The Guangdong Province Education Department under contract No.GCZX-A0909the Guangdong Province Ocean and Fisheries Science & Technology Extension Project under contract No.20120980+1 种基金the Guangdong Province Industry-University-Science Partnership Project under contract No.20110908the Science&Technology Project of Huaiyin Normal University under contract No.WH0031
文摘Superoxide dismutase（SOD） is a crucial antioxidant enzyme playing the first defense line in antioxidant pathways against reactive oxygen species in various organisms including marine invertebrates. There exist mainly two specific forms, Cu/Zn-SOD（SOD1） and Mn-SOD（SOD2）, in eukaryotes. SODs are known to be concurrently modulated by a variety of environmental stressors. By using central composite experimental design and response surface method, the joint effects of water temperature（18–34°C） and copper ion concentration（0.1–1.5 mg/L） on the total SOD activity in the digestive gland of Crassostrea ariakensis were studied. The results showed that the linear effect of temperature was highly significant（P〈0.01）, the quadratic effect of temperature was significant（P〈0.05）; the linear effect of copper ion concentration was not significant（P〉0.05）, while the quadratic effect of copper ion concentration was highly significant（P〈0.01）; the interactive effect of temperature and copper ion concentration was not significant（P〉0.05）; the effect of temperature was greater than that of copper ion concentration. The model equation of digestive gland SOD enzyme activity towards the two factors of interest was established, with R2 and predictive R2 as high as 0.961 6 and 0.820 7, respectively, suggesting that the goodness-offit to experimental data be very satisfactory, and could be applied to prediction of digestive gland SOD activity in C. ariakensis under the conditions of the experiment. Our results would be conducive to addressing the health of aquatic animals and/or to detecting environmental problems by taking SOD as a potential bioindicator.
基金financially supported by the National Key Research and Development program(No.2017YFC0211302)the National Natural Science Foundation of China(No.21676195)+1 种基金the Science Fund of State Key Laboratory of Engine Reliability(No.skler-201714)finical support from GM Global Research&Development(No.GAC1539)
文摘Copper-exchanged chabazite（Cu/CHA） catalysts have been found to be affected by alkali metal and alkaline earth ions. However, the effects of Na＋ ions on Cu/SAPO-34 for ammonia selective catalytic reduction（NH_3-SCR） are still unclear. In order to investigate the mechanism, five samples with various Na contents were synthesized and characterized. It was observed that the introduced Na＋ ion-exchanges with H＋and Cu2＋of Cu/SAPO-34. The exchange of H＋is easier than that of isolated Cu2＋. The exchanged Cu2＋ions aggregate and form ＂CuAl_2O4-like＂ species.The NH_3-SCR activity of Cu/SAPO-34 decreases with increasing Na content, and the loss of isolated Cu2＋and acid sites is responsible for the activity loss.
文摘We use the extended gate field effect transistor (EGFET)as the structure of the chlorine ion sensor,and the chlorine ion ionophores (ETH9033 and TDDMAC1)are incorporated into solvent polymeric membrane (PVC/DOS),then the chlorine ion selective membrane is formed on the sensing window,and the fabrication of the EGFET chlorine ion sensing device is completed.The surface potential on the sensing membrane of the EGFET chlorine ion sensing device will be changed in the different chlorine ion concentration solutions,then changes further gate voltage and drain current to detect chlorine ion concentration.We will study non-ideal effects such as temperature,hysteresis and drift effects for the EGFET chlorine ion sensing device in this paper,these researches will help us to improve the sensing characteristics of the EGFET chlorine ion sensing device.
基金the National Natural Science Foundation of China! No.196O5005)
文摘To explore the survival and dose response of organism for different radiation sources is of great importance in the research of radiobiology. In this study, the survival-dose response of Deinococcus radiodurans (E.coli, as the control) for ultra-violet (UV), γ-rays radiation and ion beam exposure was investigated. The shoulder type of survival curves were found for both UV and γ-ray ionizing radiation, but the saddle type of survival curves were shown for H+、 N+( 20keV and 30keV) and Ar+ beam exposure. This dose effect of the survival initially decreased with the increase in dose and then increased in the high dose range and finally decreased again in the higher dose range. Our experimental results suggest that D. radiodurans, which is considerably radio-resistant to UV and x-ray and γ-ray ionizing radiation, do not resist ion beam exposure.
