The photoionization of seeded carbon bisulfide molecular beam by a 1064nm nanosecond Nd-YAG laser with intensities varying from 0.8 × 10^11 to 5.6 × 10^11 W/cm^2 have been studied by time-of-flight mass spec...The photoionization of seeded carbon bisulfide molecular beam by a 1064nm nanosecond Nd-YAG laser with intensities varying from 0.8 × 10^11 to 5.6 × 10^11 W/cm^2 have been studied by time-of-flight mass spectrometry. Multiply charged ions of S^q＋ （q = 2 6） and C^q＋ （q = 2-4） with kinetic energy of hundreds of electron volts have been observed, and there are strong experimental evidences indicating that those multicharged ions originate from the ionization of CS2 neat clusters in the beam. An electron reeolliding ionization model is proposed to explain the appearance of those multiply charged atomic ions under such low laser intensities.展开更多
A new method for the generation of high charged state metal ion beams is developed. This method is based on microwave heating of vacuum arc plasma in a magnetic trap under electron cyclotron resonance （ECR） conditio...A new method for the generation of high charged state metal ion beams is developed. This method is based on microwave heating of vacuum arc plasma in a magnetic trap under electron cyclotron resonance （ECR） conditions. Two gyrotrons for plasma heating were used, which were with the following parameters. The first is with a wave frequency of 37.5 GHz, a pulse duration of 1 ms and power of 100 kW, another is with 75 GHz, 0.15 ms and 400 kW. Two different magnetic traps were considered for vacuum arc plasma confinement. The first one is a simple mirror trap. Such system was already investigated and could provide high charge state ions. The second trap was with a cusp magnetic field configuration with native ＂minimum-B＂ field structure. Two different ways of metal plasma injection into the magnetic trap were used. The first one is an axial injection from an arc source located out of the trap, and the second is a radial injection from four arc sources mounted at the center of the trap. Both traps provide up to 200 eMA of ion beam current for platinum ions with highest charge state 10＋. Ion beams were successfully extracted from the plasma and accelerated by a voltage of up to 20 kV.展开更多
Multicharged supramolecular assemblies based on luminescent macrocycle play an important role in extending their optical properties and functions.Herein,we reported macrocyclic supramolecular assemblies based on lumin...Multicharged supramolecular assemblies based on luminescent macrocycle play an important role in extending their optical properties and functions.Herein,we reported macrocyclic supramolecular assemblies based on luminescent terphen[3]arene sulfate(TP[3]AS)and tetraphenylethylene pyridinium(TPE-4Py)through electrostatic interactions,host-vip encapsulation andπ-πstacking interactions.F?rster resonance energy transfer(FRET)process from TP[3]AS to TPE-4Py was achieved with the energy transfer efficiency of 99.9%,accompanied by TPE-4Py fluorescence emission bathochromic shifted of 15 nm and enhanced by 1.68 times in PBS solution.In contrast,other non-luminescent sulfato-β-cyclodextrin and sulfobutylether-β-cyclodextrin only can enhance the fluorescence intensity of TPE-4Py without bathochromic shift.Due to the strong fluorescence and good stability of TPE-4Py@TP[3]AS,it can be used for optical imaging in living cells,which provided an effective approach for the construction of assembling-confined luminescent biomaterials.展开更多
Molecular aggregation or supramolecular aggregation-induced emission is one of the research hotspots in chemistry,biology,and materials.Herein,we report negatively charged sulfato-β-cyclodextrin(SCD)induced cyanoviny...Molecular aggregation or supramolecular aggregation-induced emission is one of the research hotspots in chemistry,biology,and materials.Herein,we report negatively charged sulfato-β-cyclodextrin(SCD)induced cyanovinylene derivatives(DPy-6C)directional aggregation to form regular nanorods(DPy-6C@SCD)through supramolecular multivalent interactions,not only achieves ultravioletvisible absorption redshifted from 453 to 521 nm but also displays near-infrared(NIR)aggregation-induced emission with a large spectral redshift of 135 nm.The DPy-6C monomer presents random nanosheets with weak fluorescence but obtains regular aggregates after assembly with SCD through electrostatic interactions.In the presence of H^(+),the DPy-6C@SCD can further aggregate into elliptical nanosheets without fluorescence changes due to the protonation of secondary amines.In contrast,the morphology of DPy-6C@SCD becomes flexible and sticks together upon the addition of OH^(−)with an emission blue shift of 72 nm and a 90-fold intensity increase because of disrupting the stacking mode of aggregates,thereby achieving acid-base regulated reversible fluorescence behaviors that cannot be realized by DPy-6C monomer.The DPy-6C@SCD can efficiently select the detection of volatile organic amines both in liquid and gas phases within 5 s at the nanomolar level.Taking advantage of RGB analysis and calculation formula application,the DPy-6C@SCD has been successfully used to monitor various organic amines on a smartphone,accompanied by naked-eye visible photoluminescence.Therefore,the present research provides an efficient directional aggregation method through supramolecular multivalent interactions,which not only realizes topological morphology transformation but also achieves reversible NIR luminescent molecular switch and high sensitivity organic amines fluorescent sensing devices.展开更多
A Simple Mirror Ion Source with 75GHz pumping(SMIS 75)has been created.The confinement system is a mirror trap with magnetic field in the plug up to 5T,variable length 15—20cm and mirror ratio 3—5.Plasma heating is ...A Simple Mirror Ion Source with 75GHz pumping(SMIS 75)has been created.The confinement system is a mirror trap with magnetic field in the plug up to 5T,variable length 15—20cm and mirror ratio 3—5.Plasma heating is performed by the microwave radiation of a gyrotron(frequency 75GHz,power up to 200kW,pulse duration up to 150μs).The first results on plasma creation,heating and confinement are presented.Gas discharge conditions and charge state distributions are investigated.The main features of the plasma are high density and short confinement time.Plasma is confined in the trap in quasi-gas-dynamic regime.This means very short rising time and very dense plasma flux.展开更多
A Simple Mirror Ion Source with 75GHz pumping(SMIS 75)has been created.The confinement system is a mirror trap with magnetic field in the plug up to 5T,variable length 15—20cm and mirror ratio 3—5.The plasma of meta...A Simple Mirror Ion Source with 75GHz pumping(SMIS 75)has been created.The confinement system is a mirror trap with magnetic field in the plug up to 5T,variable length 15—20cm and mirror ratio 3—5.The plasma of metal ions is injected into the trap by a special vacuum arc minigun.Plasma heating is performed by the microwave radiation of a gyrotron(the frequency of 75GHz,power up to 200kW,pulse duration up to 150μs).The results of the experiment have demonstrated substantial multiple ionization of metal ions.For a metal with high melting temperature(Pt),heating shifts the average ion charge from Pt^(2+) up to Pt^(7+).Maximum stripped observed ion is Pt^(10+).Total current of ion beam is about 300mA.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No 20573111） and the Centre for Computational Science, Hefei Institutes of Physics, China （Grant No 0331405002）. Acknowledgment We thank Professor Cunhao Zhang and Professor Guohe Sha for their instructive discussion.
文摘The photoionization of seeded carbon bisulfide molecular beam by a 1064nm nanosecond Nd-YAG laser with intensities varying from 0.8 × 10^11 to 5.6 × 10^11 W/cm^2 have been studied by time-of-flight mass spectrometry. Multiply charged ions of S^q＋ （q = 2 6） and C^q＋ （q = 2-4） with kinetic energy of hundreds of electron volts have been observed, and there are strong experimental evidences indicating that those multicharged ions originate from the ionization of CS2 neat clusters in the beam. An electron reeolliding ionization model is proposed to explain the appearance of those multiply charged atomic ions under such low laser intensities.
基金supported by the Russian Foundation for Basic Research (grant #11-08-00259)by the Ministry of Education and Science of theRussian Federation (state contract No. 14.740.11.1333)
文摘A new method for the generation of high charged state metal ion beams is developed. This method is based on microwave heating of vacuum arc plasma in a magnetic trap under electron cyclotron resonance （ECR） conditions. Two gyrotrons for plasma heating were used, which were with the following parameters. The first is with a wave frequency of 37.5 GHz, a pulse duration of 1 ms and power of 100 kW, another is with 75 GHz, 0.15 ms and 400 kW. Two different magnetic traps were considered for vacuum arc plasma confinement. The first one is a simple mirror trap. Such system was already investigated and could provide high charge state ions. The second trap was with a cusp magnetic field configuration with native ＂minimum-B＂ field structure. Two different ways of metal plasma injection into the magnetic trap were used. The first one is an axial injection from an arc source located out of the trap, and the second is a radial injection from four arc sources mounted at the center of the trap. Both traps provide up to 200 eMA of ion beam current for platinum ions with highest charge state 10＋. Ion beams were successfully extracted from the plasma and accelerated by a voltage of up to 20 kV.
基金the National Natural Science Foundation of China(Nos.21971192,21807038)the Tianjin Municipal Education Commission(No.2021KJ188)the China Postdoctoral Science Foundation(No.2021T140343)。
文摘Multicharged supramolecular assemblies based on luminescent macrocycle play an important role in extending their optical properties and functions.Herein,we reported macrocyclic supramolecular assemblies based on luminescent terphen[3]arene sulfate(TP[3]AS)and tetraphenylethylene pyridinium(TPE-4Py)through electrostatic interactions,host-vip encapsulation andπ-πstacking interactions.F?rster resonance energy transfer(FRET)process from TP[3]AS to TPE-4Py was achieved with the energy transfer efficiency of 99.9%,accompanied by TPE-4Py fluorescence emission bathochromic shifted of 15 nm and enhanced by 1.68 times in PBS solution.In contrast,other non-luminescent sulfato-β-cyclodextrin and sulfobutylether-β-cyclodextrin only can enhance the fluorescence intensity of TPE-4Py without bathochromic shift.Due to the strong fluorescence and good stability of TPE-4Py@TP[3]AS,it can be used for optical imaging in living cells,which provided an effective approach for the construction of assembling-confined luminescent biomaterials.
基金National Natural Science Foundation of China,Grant/Award Numbers:21971192,21807038Tianjin Municipal Education Commission,Grant/Award Number:2021KJ188China Postdoctoral Science Foundation,Grant/Award Number:2021T140343。
文摘Molecular aggregation or supramolecular aggregation-induced emission is one of the research hotspots in chemistry,biology,and materials.Herein,we report negatively charged sulfato-β-cyclodextrin(SCD)induced cyanovinylene derivatives(DPy-6C)directional aggregation to form regular nanorods(DPy-6C@SCD)through supramolecular multivalent interactions,not only achieves ultravioletvisible absorption redshifted from 453 to 521 nm but also displays near-infrared(NIR)aggregation-induced emission with a large spectral redshift of 135 nm.The DPy-6C monomer presents random nanosheets with weak fluorescence but obtains regular aggregates after assembly with SCD through electrostatic interactions.In the presence of H^(+),the DPy-6C@SCD can further aggregate into elliptical nanosheets without fluorescence changes due to the protonation of secondary amines.In contrast,the morphology of DPy-6C@SCD becomes flexible and sticks together upon the addition of OH^(−)with an emission blue shift of 72 nm and a 90-fold intensity increase because of disrupting the stacking mode of aggregates,thereby achieving acid-base regulated reversible fluorescence behaviors that cannot be realized by DPy-6C monomer.The DPy-6C@SCD can efficiently select the detection of volatile organic amines both in liquid and gas phases within 5 s at the nanomolar level.Taking advantage of RGB analysis and calculation formula application,the DPy-6C@SCD has been successfully used to monitor various organic amines on a smartphone,accompanied by naked-eye visible photoluminescence.Therefore,the present research provides an efficient directional aggregation method through supramolecular multivalent interactions,which not only realizes topological morphology transformation but also achieves reversible NIR luminescent molecular switch and high sensitivity organic amines fluorescent sensing devices.
文摘A Simple Mirror Ion Source with 75GHz pumping(SMIS 75)has been created.The confinement system is a mirror trap with magnetic field in the plug up to 5T,variable length 15—20cm and mirror ratio 3—5.Plasma heating is performed by the microwave radiation of a gyrotron(frequency 75GHz,power up to 200kW,pulse duration up to 150μs).The first results on plasma creation,heating and confinement are presented.Gas discharge conditions and charge state distributions are investigated.The main features of the plasma are high density and short confinement time.Plasma is confined in the trap in quasi-gas-dynamic regime.This means very short rising time and very dense plasma flux.
文摘A Simple Mirror Ion Source with 75GHz pumping(SMIS 75)has been created.The confinement system is a mirror trap with magnetic field in the plug up to 5T,variable length 15—20cm and mirror ratio 3—5.The plasma of metal ions is injected into the trap by a special vacuum arc minigun.Plasma heating is performed by the microwave radiation of a gyrotron(the frequency of 75GHz,power up to 200kW,pulse duration up to 150μs).The results of the experiment have demonstrated substantial multiple ionization of metal ions.For a metal with high melting temperature(Pt),heating shifts the average ion charge from Pt^(2+) up to Pt^(7+).Maximum stripped observed ion is Pt^(10+).Total current of ion beam is about 300mA.
