Considering that the equilateral triangle structure of H3- cluster can be formed from the interaction of H- with two hydrogen atoms, a modified arrangement channel quantum mechanics method has been used to calculate t...Considering that the equilateral triangle structure of H3- cluster can be formed from the interaction of H- with two hydrogen atoms, a modified arrangement channel quantum mechanics method has been used to calculate the total energy curve for this structure. The result shows that the curve has a minimal energy -1.6672 a.u. at an internuclear distance of 1.77a0, so its dissociation energy (binding energy) is D(H- + H+ H) = 0.1395 a.u. This means that the cluster H3- may be formed in an equilateral triangle structure with a bond length of 1.77a0.展开更多
Transmission data for 12 MV bremsstrahlung beams produced by the process for continuous-pulsed 12 MV electrons coming from a linear accelerator hitting a 1.2mm thick plane tantalum target have been acquired with a com...Transmission data for 12 MV bremsstrahlung beams produced by the process for continuous-pulsed 12 MV electrons coming from a linear accelerator hitting a 1.2mm thick plane tantalum target have been acquired with a combination of iron and Telfon attenuators. Two solid state dosimeters with LiF-TLD material surrounded Telfon were used as detectors. It has been checked that the experimental system achieves reasonably narrow-beam geometry by Monte Carlo simulations. From these transmission data, the original energy photon spectrum has been reconstructed using the iterative least-squares technique and compared with the spectrum calculated with Monte Carlo code system EGSnrc. The comparison shows that the numerical technique for analysis of transmission data can represent 12 MV bremsstrahlung spectrum acceptably well. The purpose of our work is to provide an effective way to reconstruct an unknown photon spectrum with high energy component and prove the correctness of this way.展开更多
Nicotinic acetylcholine receptors(nChRs) are involved in the various pharmacological effects or disease states.In order to study the central nChRs by PET or SPECT,some radioligands have been investigated.In this paper...Nicotinic acetylcholine receptors(nChRs) are involved in the various pharmacological effects or disease states.In order to study the central nChRs by PET or SPECT,some radioligands have been investigated.In this paper,the procedure for synthesis of 2-[^18F] fluoro-3-[2(S)-2-azetidinylmethoxy]pyridine(2-[^18F0-A-85380),a potential PET ligand for in vivo imaging nicotinic acetylcholine receptor was described.2-[^18F]-A-85380 was prepared from the precursor,2-nitro-3-[(1-(tert-butoxycarbonyl)-2-(S0-azetidinyl)methoxy] pyridine(4),which was synthesized with commercial (S)-2-zaetid-inecarboxylic acid as starting material.The whole procedure for radiosynthesis and purification was executed in about 1h and 45-55% of the added fluorine-18 was found in the purified 2-[^18F]-A-85380,with specific activity of 1.0-2.2×10^11 Bq/umol.展开更多
The design of a small complex-type focussed magnetron with a long target-life used for excited multi-atoms beam film deposition in hard coatings is described.The magnetron tunnel of the magentron source was constructe...The design of a small complex-type focussed magnetron with a long target-life used for excited multi-atoms beam film deposition in hard coatings is described.The magnetron tunnel of the magentron source was constructed by a planar unbalanced magnetic annulus,which comes from the extended co-axial magnetron principle and inside cylindrical magnet tunnel.The use efficinecy of inside circular cone sputtering target area is high up to 62%.The inside-inversion cone sputtering target has a long life and results in a higher deposition rate 35nm/min for Ti at a 2.5Pa Ar pressure.A better focussing direction of ejecting atom beam has been achieved,and the are power input is 300W for Ti target.展开更多
The influence of surface barrier of solid upon ion reflection was studied in a few papers of other authors by using the Monte-Carlo simulation. Based on the bipartition model of ion transport, a new analytical theory ...The influence of surface barrier of solid upon ion reflection was studied in a few papers of other authors by using the Monte-Carlo simulation. Based on the bipartition model of ion transport, a new analytical theory has been developed instead of the MC simulation, due to important implication of the effect for fusion research. In the present paper we have calculated the number reflection coefficients of H+, D+, He and T+ normally incident on C,Al and Cu for ion energy from several eV to one hundred keV respectively. Our computational results accorded with the MC simulation. The results have shown that the effect of surface barrier on ion reflection becomes evident when the energy of incident ions is lower than one keV. In particular, for the ion energy from several eV to one hun dred eV, the discrepancies of number reflection coefficients can increase up to 0.1～0.3, showing this influence to be very important.展开更多
ZrO2 films on NaCl(100) substrate produced by oxygen ion bombardment and argon ion sputtering of Zr are analysed using TEM, XRD and XPS. The result of TEM shows that only cubic phase exists for the ZrO2 film produced ...ZrO2 films on NaCl(100) substrate produced by oxygen ion bombardment and argon ion sputtering of Zr are analysed using TEM, XRD and XPS. The result of TEM shows that only cubic phase exists for the ZrO2 film produced by oxygen ion bombardment with 30μA/cm2 and 200eV, while the XRD result shows that there seems to exhibit a small quanitity of monoclinic phase apart from cubic one under the production condition of oxygen ion of 25μA/cm2, 100eV.展开更多
CdS films prepared with chemical pyrolysis deposition (CPD) at differ- ent temperature during film growth were characterized by XRD. Hexagon-like struc- ture appeared at the temperature of 350-500℃, while wurtzite ph...CdS films prepared with chemical pyrolysis deposition (CPD) at differ- ent temperature during film growth were characterized by XRD. Hexagon-like struc- ture appeared at the temperature of 350-500℃, while wurtzite phase was observed at temperature of 540℃ during film growth. Also CdS films prepared by CPD at 400℃ were undergone post annealing at different temperature of 200-600℃ or post Ar+ ion irradiation. It is found that wurtzite phase happened when the annealing temperature rose to 600℃. And hexagon-like structure existed at the annealing temperature from 25℃ to near 500℃. Ar+ ion irradiation could not cause phase transformation. but induce some preferred orientations and an increase in grain size for the CdS films.展开更多
The extraction behavior of uranium(VI) from thiocyanate medium with dibenzo-18-crown-6 (DBC) in nitrobenzene and the effects of alkali canons on the extraction were investigated. The results showed that the uranium (V...The extraction behavior of uranium(VI) from thiocyanate medium with dibenzo-18-crown-6 (DBC) in nitrobenzene and the effects of alkali canons on the extraction were investigated. The results showed that the uranium (VI) can be effectively extracted in the presence of potassium canon, uranium (VI) is extracted as complex anionic species UO2(SCN)2, and the stoichiometry of the extracted complex is KUO2(SCN)32DBC(o)’展开更多
文摘Considering that the equilateral triangle structure of H3- cluster can be formed from the interaction of H- with two hydrogen atoms, a modified arrangement channel quantum mechanics method has been used to calculate the total energy curve for this structure. The result shows that the curve has a minimal energy -1.6672 a.u. at an internuclear distance of 1.77a0, so its dissociation energy (binding energy) is D(H- + H+ H) = 0.1395 a.u. This means that the cluster H3- may be formed in an equilateral triangle structure with a bond length of 1.77a0.
文摘Transmission data for 12 MV bremsstrahlung beams produced by the process for continuous-pulsed 12 MV electrons coming from a linear accelerator hitting a 1.2mm thick plane tantalum target have been acquired with a combination of iron and Telfon attenuators. Two solid state dosimeters with LiF-TLD material surrounded Telfon were used as detectors. It has been checked that the experimental system achieves reasonably narrow-beam geometry by Monte Carlo simulations. From these transmission data, the original energy photon spectrum has been reconstructed using the iterative least-squares technique and compared with the spectrum calculated with Monte Carlo code system EGSnrc. The comparison shows that the numerical technique for analysis of transmission data can represent 12 MV bremsstrahlung spectrum acceptably well. The purpose of our work is to provide an effective way to reconstruct an unknown photon spectrum with high energy component and prove the correctness of this way.
文摘Nicotinic acetylcholine receptors(nChRs) are involved in the various pharmacological effects or disease states.In order to study the central nChRs by PET or SPECT,some radioligands have been investigated.In this paper,the procedure for synthesis of 2-[^18F] fluoro-3-[2(S)-2-azetidinylmethoxy]pyridine(2-[^18F0-A-85380),a potential PET ligand for in vivo imaging nicotinic acetylcholine receptor was described.2-[^18F]-A-85380 was prepared from the precursor,2-nitro-3-[(1-(tert-butoxycarbonyl)-2-(S0-azetidinyl)methoxy] pyridine(4),which was synthesized with commercial (S)-2-zaetid-inecarboxylic acid as starting material.The whole procedure for radiosynthesis and purification was executed in about 1h and 45-55% of the added fluorine-18 was found in the purified 2-[^18F]-A-85380,with specific activity of 1.0-2.2×10^11 Bq/umol.
文摘The design of a small complex-type focussed magnetron with a long target-life used for excited multi-atoms beam film deposition in hard coatings is described.The magnetron tunnel of the magentron source was constructed by a planar unbalanced magnetic annulus,which comes from the extended co-axial magnetron principle and inside cylindrical magnet tunnel.The use efficinecy of inside circular cone sputtering target area is high up to 62%.The inside-inversion cone sputtering target has a long life and results in a higher deposition rate 35nm/min for Ti at a 2.5Pa Ar pressure.A better focussing direction of ejecting atom beam has been achieved,and the are power input is 300W for Ti target.
基金Supported by the National Natural Science Foundation of China (No. 19375032) and International Atomic Energy Agency (Contract No. 8064/RB)
文摘The influence of surface barrier of solid upon ion reflection was studied in a few papers of other authors by using the Monte-Carlo simulation. Based on the bipartition model of ion transport, a new analytical theory has been developed instead of the MC simulation, due to important implication of the effect for fusion research. In the present paper we have calculated the number reflection coefficients of H+, D+, He and T+ normally incident on C,Al and Cu for ion energy from several eV to one hundred keV respectively. Our computational results accorded with the MC simulation. The results have shown that the effect of surface barrier on ion reflection becomes evident when the energy of incident ions is lower than one keV. In particular, for the ion energy from several eV to one hun dred eV, the discrepancies of number reflection coefficients can increase up to 0.1～0.3, showing this influence to be very important.
文摘ZrO2 films on NaCl(100) substrate produced by oxygen ion bombardment and argon ion sputtering of Zr are analysed using TEM, XRD and XPS. The result of TEM shows that only cubic phase exists for the ZrO2 film produced by oxygen ion bombardment with 30μA/cm2 and 200eV, while the XRD result shows that there seems to exhibit a small quanitity of monoclinic phase apart from cubic one under the production condition of oxygen ion of 25μA/cm2, 100eV.
基金Partly supported by the Visiting Scholar Funds of The Key Laboratory in University of China
文摘CdS films prepared with chemical pyrolysis deposition (CPD) at differ- ent temperature during film growth were characterized by XRD. Hexagon-like struc- ture appeared at the temperature of 350-500℃, while wurtzite phase was observed at temperature of 540℃ during film growth. Also CdS films prepared by CPD at 400℃ were undergone post annealing at different temperature of 200-600℃ or post Ar+ ion irradiation. It is found that wurtzite phase happened when the annealing temperature rose to 600℃. And hexagon-like structure existed at the annealing temperature from 25℃ to near 500℃. Ar+ ion irradiation could not cause phase transformation. but induce some preferred orientations and an increase in grain size for the CdS films.
基金Nuclear Industrial Science Foundation of China (J 95 GY 403)
文摘The extraction behavior of uranium(VI) from thiocyanate medium with dibenzo-18-crown-6 (DBC) in nitrobenzene and the effects of alkali canons on the extraction were investigated. The results showed that the uranium (VI) can be effectively extracted in the presence of potassium canon, uranium (VI) is extracted as complex anionic species UO2(SCN)2, and the stoichiometry of the extracted complex is KUO2(SCN)32DBC(o)’
