We report the results of the experiment on synthesizing ^(287,288)Mc isotopes (Z=115) using the fusionevaporation reaction ^(243)Am(^(48)Ca,4n,3n)^(287,288)Mc at the Spectrometer for Heavy Atoms and Nuclear Structure-...We report the results of the experiment on synthesizing ^(287,288)Mc isotopes (Z=115) using the fusionevaporation reaction ^(243)Am(^(48)Ca,4n,3n)^(287,288)Mc at the Spectrometer for Heavy Atoms and Nuclear Structure-2(SHANS2),a gas-filled recoil separator located at the China Accelerator Facility for Superheavy Elements(CAFE2).In total,20 decay chains are attributed to ^(288)Mc and 1 decay chain is assigned to ^(287)Mc.The measured oa-decay properties of ^(287,288)Mc as well as its descendants are consistent with the known data.No additional decay chains originating from the 2n or 5n reaction channels were detected.The excitation function of the ^(243)Am(^(48)Ca,3n)^(288)Mc reaction was measured at the cross-section level of picobarn,which indicates the promising capability for the study of heavy and superheavy nuclei at the facility.展开更多
A time-of-flight Highly Granular Neutron Detector(HGND)with a multilayer longitudinal structure of interleaved absorber and scintillator plates,high transverse granularity,and time resolution of approximately 150 ps i...A time-of-flight Highly Granular Neutron Detector(HGND)with a multilayer longitudinal structure of interleaved absorber and scintillator plates,high transverse granularity,and time resolution of approximately 150 ps is currently under development.The detector is designed to identify neutrons produced in nucleus-nucleus collisions and measure neutron kinetic energies of 0.3-4 GeV by the time-of-flight method in the BM@N experiment at the NICA accelerator complex at JINR.To validate the concept of full-scale HGND,a compact HGND prototype was first designed and built,and its performance was studied in the BM@N experiment.The acceptance of the HGND prototype and the detection efficiency of forward neutrons emitted in hadronic fragmentation and electromagnetic dissociation(EMD)of 3.8A GeV124Xe projectiles interacting with a CsI target were calculated by means of the DCM-QGSM-SMM and RELDIS models,respectively.The energy distributions of the forward spectator neutrons and neutrons from the EMD were measured and compared with the simulations.The developed methods will be used to calibrate the full-scale HGND and study its efficiency.展开更多
Two-and three-component deep eutectic solvents(DES)based on acrylic acid(AA),acrylamide(AAm),and choline chloride(ChCl)were used to disintegrate bacterial cellulose into cellulose nanofibers(CNF).As a result,polymeriz...Two-and three-component deep eutectic solvents(DES)based on acrylic acid(AA),acrylamide(AAm),and choline chloride(ChCl)were used to disintegrate bacterial cellulose into cellulose nanofibers(CNF).As a result,polymerizable precursors suitable for 3D printing with CNF as a rheology modifier and reinforcer with formation of interpenetrating double polymer network were obtained after UV curing.Composite hydrogels were formed by replacing ChCl with water.It was found that the introduction of amide groups into the acrylate polymer matrix resulted in an increase in compressive strength.The layered architecture of the 3D printed products provides greater mechanical strength compared to molded products.The structure of the composites was investigated using wide-angle X-ray scattering(WAXS),small-angle X-ray scattering(SAXS),atomic force microscopy(AFM)and polarized light microscopy.These studies suggest that the enhanced mechanical properties of the 3D printed hydrogels are associated with swelling and branching of CNF in the DES,as well as alignment of the filler during extrusion.For comparative analysis,composite hydrogels were also prepared using aqueous solutions of AA and AA/AAm with dispersed CNF.However,the 3D printing process was hampered in this case due to cellulose agglomeration.Mechanical testing revealed the formation of premature microcracks in these samples,which were not observed in composites produced using DES.Cytotoxicity of the composite hydrogels was also tested.The results provide valuable insights into the production of strong(up to 3.4 MPa)homogeneous composite hydrogels using 3D printing with nanocellulose filler.展开更多
Ferromagnetic high damping(FHA)alloys with a wide temperature range from-150℃to 300℃have unique application value in extreme environments.In the present work,the damping behaviors of Fe-21 Ga-xLa(x=0.12 wt.%,0.24 wt...Ferromagnetic high damping(FHA)alloys with a wide temperature range from-150℃to 300℃have unique application value in extreme environments.In the present work,the damping behaviors of Fe-21 Ga-xLa(x=0.12 wt.%,0.24 wt.%,0.47 wt.%,1.18 wt.%,and 2.33 wt.%La)alloys have been studied in detail,and a new phenomenological model has been proposed.With the increase of La content,the Laves phase(LaGa_(2))in the matrix increases gradually,and the resistance opposing the domain movement increases as well.Combined with the results of synchrotron radiation X-ray diffraction,neutron diffraction,and magnetic domain observation,the resistance mainly comes from three parts:the average stress related to the lattice distortion of the matrix,the average stress related to the increasing area energy of domain walls(DWs),and the ave rage stress related to the increasing demagnetization energy induced by the Laves phase.Different from the traditional method of reducing internal stress through annealing to improve the damping capacity,the proper internal stress barriers are necessary to Barkhausen jumps to dissipate energy.Therefore,proper doping to balance resistance and mobility of DWs is a reliable way to improve damping capacity.Meanwhile,for Fe-Al and Fe-Cr based Alloys,the new model also has a good fitting effect.This study provides a theoretical and experimental reference for improving the functional properties of ferromagnetic alloys.展开更多
We discuss a hardship in synthesis of heaviest super heavy elements in massive nuclei reactions due to the hindrance to complete fusion of reacting nuclei caused on the onset of quasifission process which strongly com...We discuss a hardship in synthesis of heaviest super heavy elements in massive nuclei reactions due to the hindrance to complete fusion of reacting nuclei caused on the onset of quasifission process which strongly competes with complete fusion and due to the strong increase of fission yields along the de-excitation cascade of the compound nucleus in comparison with the evaporation residue formation.The hindrance to formation of compound nucleus and evaporation residue is determined by the characteristic of the entrance channel.展开更多
Laser irradiation device for the protection of biological objects from the action of ionizing radiation to be used in practice has been manufactured （invention patent RU 2 428 228 C2）. Research of the action of y-ra...Laser irradiation device for the protection of biological objects from the action of ionizing radiation to be used in practice has been manufactured （invention patent RU 2 428 228 C2）. Research of the action of y-radiation itself as well as of the combined action of laser devices on survival, weight, skin and the general mitotic index of the bone marrow cells （mitotic index of all nucleus-containing cells of the bone marrow） of C57BL/6 experimental young mice was carried out. The mice were irradiated with ionizing （whole body irradiation） and laser radiation, separately one by one in a special frame device. Laser radiation in the dose 1 mJ/cm^2 irradiated only the back of a mouse, or both the back and the abdomen of mice. In case of combined irradiation of mice, the time interval between two types of irradiation did not exceed 30 min. First, the mice were exposed to y-radiation then to laser radiation. The method of the laser radiation-protection of biological subjects contributes to an increase in the viability of mice, prevents the damages of skin and also increases the mitotic activity of mice bone marrow cells.展开更多
The formamide-titanium oxide interaction mechanism is a research target of great importance for understanding the elementary events of the origin of life: the synthesis of nucleoside bases and formation of biological ...The formamide-titanium oxide interaction mechanism is a research target of great importance for understanding the elementary events of the origin of life: the synthesis of nucleoside bases and formation of biological molecules needed for life. Titanium oxide (TiO2) can act as a strongly adsorbing surface or a catalytic material. In the present study, a comparative molecular dynamics analysis performed to clarify the adsorbing and diffusion properties of liquid formamide on a TiO2 surface in the presence of water molecules. The structural features of the formamide concentration effect (the accumulation of molecules) on a TiO2 surface in the presence and absence of water solvent are cleared up. Modification of the formamide diffusion abilities mediated by a water solvent is observed to correlate with the formamide-water concentration distribution on the surface.展开更多
A database system,known as the large PMT characterization and instrumentation database system(LPMT-CIDS),was designed and implemented for the Jiangmen Underground Neutrino Observatory(JUNO).The system is based on a Li...A database system,known as the large PMT characterization and instrumentation database system(LPMT-CIDS),was designed and implemented for the Jiangmen Underground Neutrino Observatory(JUNO).The system is based on a Linux+Apache+MySQL+PHP(LAMP)server and focuses on modularization and architecture separation.It covers all the testing stages for the 20-inch photomultiplier tubes(PMTs)at JUNO and provides its users with data storage,analysis,and visualization services.Based on the successful use of the system in the 20-inch PMT testing program,its design approach and construction elements can be extended to other projects.展开更多
A twin gridded ionization chamber with dual parameter data acquisition sys-tem is used to study neutron induced charged particle emission reaction.The angulardistribution and cross section of n-particles from the <...A twin gridded ionization chamber with dual parameter data acquisition sys-tem is used to study neutron induced charged particle emission reaction.The angulardistribution and cross section of n-particles from the <sup>64</sup>Zn（n,α）<sup>61</sup>Ni reaction are meas-ured at neutron energy 5 MeV.展开更多
In 2018,the STAR collaboration collected data from^(96)_(44)Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zr at√^(S)NN=200 Ge V to search for the presence of the chiral magnetic effect in collisions of nuclei.The isobar ...In 2018,the STAR collaboration collected data from^(96)_(44)Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zr at√^(S)NN=200 Ge V to search for the presence of the chiral magnetic effect in collisions of nuclei.The isobar collision species alternated frequently between 9644 Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zr.In order to conduct blind analyses of studies related to the chiral magnetic effect in these isobar data,STAR developed a three-step blind analysis procedure.Analysts are initially provided a"reference sample"of data,comprised of a mix of events from the two species,the order of which respects time-dependent changes in run conditions.After tuning analysis codes and performing time-dependent quality assurance on the reference sample,analysts are provided a species-blind sample suitable for calculating efficiencies and corrections for individual≈30-min data-taking runs.For this sample,species-specific information is disguised,but individual output files contain data from a single isobar species.Only run-by-run corrections and code alteration subsequent to these corrections are allowed at this stage.Following these modifications,the"frozen"code is passed over the fully un-blind data,completing the blind analysis.As a check of the feasibility of the blind analysis procedure,analysts completed a"mock data challenge,"analyzing data from Au+Au collisions at√^(S)NN=27 Ge V,collected in 2018.The Au+Au data were prepared in the same manner intended for the isobar blind data.The details of the blind analysis procedure and results from the mock data challenge are presented.展开更多
The superconducting cyclotron SC200 is intended to generate a 200 MeV, 400 nA proton beam for future particle therapy. The internal hot-cathode-type Penning ionization gauge (PIG) ion source for the SC200 is designed ...The superconducting cyclotron SC200 is intended to generate a 200 MeV, 400 nA proton beam for future particle therapy. The internal hot-cathode-type Penning ionization gauge (PIG) ion source for the SC200 is designed for the generation of hydrogen ions. A brief description of the design of ion source and test bench, which are used in SC200, is given in this paper. The ion source has been verified on the test bench, and the results indicated that the designed ion source meets the expected requirements. The lifetime of the filament exceeded 100 h in the test. In addition, the extraction voltage and the gas flow that influence the extracted ion current intensity have been tested in the experiment.展开更多
We study the evolution of the dark energy parameter within the scope of a spatially homogeneous and isotropic Friedmann-Robertson-Walker(FRW)model filled with barotropic fluid and dark energy.To obtain the determinist...We study the evolution of the dark energy parameter within the scope of a spatially homogeneous and isotropic Friedmann-Robertson-Walker(FRW)model filled with barotropic fluid and dark energy.To obtain the deterministic solution we choose the scale factor a(t)=(√te^(t)),which yields a time-dependent deceleration parameter(DP).In doing so,we consider the case minimally coupled with dark energy to the perfect fluid as well as direct interaction with it.展开更多
Octupole deformation bands built onπh ll/2 orbital in neutron-rich odd-Z 145,147La nuclei have been investigated by measuring the promptγ-rays emitted from the 252Cf source.The alternating parity band structures and...Octupole deformation bands built onπh ll/2 orbital in neutron-rich odd-Z 145,147La nuclei have been investigated by measuring the promptγ-rays emitted from the 252Cf source.The alternating parity band structures and strong E1 transitions observed between negative-and positive-parity bands in both nuclei indicate the octupole deformation enhanced by the h ll/2 single proton coupling.According to observed energy displacements the octupole deformation becomes stable at the intermediate spin states.展开更多
High spin states in neutron-rich odd-N ^(145)Ba nucleus have been investigated from study of promptγ-rays in spontaneous fission of^(252)Cf.The alternating parity bands are identified indicating octupole deformation ...High spin states in neutron-rich odd-N ^(145)Ba nucleus have been investigated from study of promptγ-rays in spontaneous fission of^(252)Cf.The alternating parity bands are identified indicating octupole deformation with simplex quantum number s=-i.The ground state band shows signature splitting and inversion at low spin.These collective band structures exhibit the competition and co-existence between symmetric and asymmetric shapes.展开更多
A molecular dynamics (MD) simulation is performed on a DNA photolyase to study the conformational behavior of the photoactive cofactor flavin adenine dinucleotide (FAD) inside the enzyme pocket. A DNA photolyase is a ...A molecular dynamics (MD) simulation is performed on a DNA photolyase to study the conformational behavior of the photoactive cofactor flavin adenine dinucleotide (FAD) inside the enzyme pocket. A DNA photolyase is a highly efficient light-driven enzyme that repairs the UV-induced cyclobutane pyrimidine dimer in damaged DNA. In this work, the FAD conformational and dynamic changes were studied within the total complex structure of a DNA photolyase protein (containing FADH–, MTHF, and DNA molecules) embedded in a water solvent. We aimed to compare the conformational changes of the FAD cofactor and other constituent fragments of the molecular system under consideration. The obtained results were discussed to gain insight into the light-driven mechanism of DNA repair by a DNA photolyase enzyme—based on the enzyme structure, the FAD mobility, and conformation shape.展开更多
Several bacterial strains of Actinomycetes belonging to Streptomyces and Arthrobacter genera for the first time were used to study the biotechnology of synthesis of gold and silver nanoparticles.The experimental condi...Several bacterial strains of Actinomycetes belonging to Streptomyces and Arthrobacter genera for the first time were used to study the biotechnology of synthesis of gold and silver nanoparticles.The experimental conditions of gold and silver nanoparticles production by the cells of studied strains in aqueous chloroauric acid(HAuCIq)and in silver nitrate(AgNO3)solutions,respectively,were determined.Concentration and time-dependences of nanoparticle formation were investigated.The complex of optical and analytical methods was used for testing the gold and silver nanoparticles in the bacterial biomass.The TEM(Transmission Electron Microscopy)and XRD(X-ray Diffraction)data in all cases demonstrated the presence of crystals with fcc(face centered cubic)structure.The results obtained show that the Actinomycetes are capable of producing gold and silver nanoparticles of spherical shape extracellularly when exposed to suitable compounds.The particle size distribution shows that the sizes of nanoparticles are in the range of 5 nm to 80 nm.The biomass obtained may be used for industrial as well as medical and pharmaceutical purposes.展开更多
The observation of an electroscalar signal during the eclipse of the Sun by the Moon in 2008 was a starting point for the development and creation of the electroscalar field theory. This observation shows that such ra...The observation of an electroscalar signal during the eclipse of the Sun by the Moon in 2008 was a starting point for the development and creation of the electroscalar field theory. This observation shows that such radiation has a long wavelength, and is longitudinal and extremely penetrating. The properties of the electroscalar and electromagnetic dynamics of a massive charged particle have been studied. An analogy between the linear theory of elasticity and Maxwell electrodynamics is made. The observed spectrum of radiation clarifying peculiar properties. Real sources of electroscalar radiation are determined. In accordance with the principle of least action, the Lagrangian of the electroscalar field and the field force acting on the particle are defined. The spectral expansion of the electroscalar field allowed us to establish that the field is longitudinal and aligned with the wave vector. At the heart of the electroscalar theory, which is compliant with the experimental data, is the four-dimensional scalar potential that describes radial vibrations of the electroscalar field source. The four-vector Maxwell electromagnetic potential and four-scalar potential neither form a single object in the Minkowski space nor interfere and, as a consequence, prove to be independent and unrelated differential relations. Moreover, a strong correlation between the spatial position of the particle and the field components allows and demonstrates a new degree of freedom in the electrodynamics of charged particles.展开更多
A new concept is introduced for the classification of “unresolved problems” in the understanding of interactions in thick targets irradiated with relativistic ions: The centre-of-mass energy per nucleon of a hypothe...A new concept is introduced for the classification of “unresolved problems” in the understanding of interactions in thick targets irradiated with relativistic ions: The centre-of-mass energy per nucleon of a hypothetical compound nucleus from a primary interaction, ECM/u, is calculated and correlated with experimental observations in thick target irradia- tions. One observes in various reactions of relativistic primary ions with thick targets that there appears to be a thresh- old energy for reactions leading to “unresolved problems” which lies around ECM/u ~ 150 MeV. All “unresolved prob- lems” are exclusively observed above this threshold, whereas below this threshold no “unresolved problems” are found. A similar threshold at 158 ± 3 MeV exists for massive pion production in nuclear interactions. Hagedorn had proposed this threshold decades ago and it is known as the Hagedorn limit. In this paper we will only mention, but not elaborate on Hagedorn’s theoretical concept any further. Some considerations will be presented and further studies in this field are suggested.展开更多
Over the past years,experimentalists have launched an expedition to explore the predicted,centered near the double-magic Z=114,N=184 nucleus.With their remarkable e orts,elements from hydrogen up to element 118 at pre...Over the past years,experimentalists have launched an expedition to explore the predicted,centered near the double-magic Z=114,N=184 nucleus.With their remarkable e orts,elements from hydrogen up to element 118 at present.The discovery of the superheavy elements o ers the possibilities to study properties of nuclei under extremely strong Coulomb elds and to explore the limits of existence of nuclei.The fusion evaporation reactions induced by low-energy heavy ions are employed for synthesis and study of superheavy isotopes,and the gas-lled recoil separator technique is always used to e ectively separate the produced evaporation residues from projectile-like and target-like products.展开更多
The new thorium isotope ^(207)Th has been produced in the 5n evaporation channel of the fusion reaction ^(36)Ar+^(176)Hf.The 197-199 MeV ^(36)Ar^(11+)beam with a typical intensity of0.4 pμA was delivered by the Secto...The new thorium isotope ^(207)Th has been produced in the 5n evaporation channel of the fusion reaction ^(36)Ar+^(176)Hf.The 197-199 MeV ^(36)Ar^(11+)beam with a typical intensity of0.4 pμA was delivered by the Sector Focusing Cyclotron of the Heavy Ion Research Facility in Lanzhou(HIRFL),China.展开更多
基金supported in part by the National Key R&D Program of China (Contract Nos.2023YFA1606500,2024YFE0109800,and 2024YFE0110400)Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB34010000)+5 种基金the Gansu Key Project of Science and Technology (Grant No.23ZDGA014)the Guangdong Major Project of Basic and Applied Basic Research (Grant No.2021B0301030006)the National Natural Science Foundation of China (Grant Nos.12105328,W2412040,12475126,12422507,12035011,12375118,12435008,and W2412043)the Chinese Academy of Sciences Project for Young Scientists in Basic Research(Grant No.YSBR-002)the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant Nos.2020409 and 2023439)the Russian Science Foundation (Grant No.25-42-00003)。
文摘We report the results of the experiment on synthesizing ^(287,288)Mc isotopes (Z=115) using the fusionevaporation reaction ^(243)Am(^(48)Ca,4n,3n)^(287,288)Mc at the Spectrometer for Heavy Atoms and Nuclear Structure-2(SHANS2),a gas-filled recoil separator located at the China Accelerator Facility for Superheavy Elements(CAFE2).In total,20 decay chains are attributed to ^(288)Mc and 1 decay chain is assigned to ^(287)Mc.The measured oa-decay properties of ^(287,288)Mc as well as its descendants are consistent with the known data.No additional decay chains originating from the 2n or 5n reaction channels were detected.The excitation function of the ^(243)Am(^(48)Ca,3n)^(288)Mc reaction was measured at the cross-section level of picobarn,which indicates the promising capability for the study of heavy and superheavy nuclei at the facility.
基金supported by the Institute for Nuclear Research of the Russian Academy of Sciences。
文摘A time-of-flight Highly Granular Neutron Detector(HGND)with a multilayer longitudinal structure of interleaved absorber and scintillator plates,high transverse granularity,and time resolution of approximately 150 ps is currently under development.The detector is designed to identify neutrons produced in nucleus-nucleus collisions and measure neutron kinetic energies of 0.3-4 GeV by the time-of-flight method in the BM@N experiment at the NICA accelerator complex at JINR.To validate the concept of full-scale HGND,a compact HGND prototype was first designed and built,and its performance was studied in the BM@N experiment.The acceptance of the HGND prototype and the detection efficiency of forward neutrons emitted in hadronic fragmentation and electromagnetic dissociation(EMD)of 3.8A GeV124Xe projectiles interacting with a CsI target were calculated by means of the DCM-QGSM-SMM and RELDIS models,respectively.The energy distributions of the forward spectator neutrons and neutrons from the EMD were measured and compared with the simulations.The developed methods will be used to calibrate the full-scale HGND and study its efficiency.
基金financially supported by part of the state assignment(No.1023031700043-2-1.4.4)。
文摘Two-and three-component deep eutectic solvents(DES)based on acrylic acid(AA),acrylamide(AAm),and choline chloride(ChCl)were used to disintegrate bacterial cellulose into cellulose nanofibers(CNF).As a result,polymerizable precursors suitable for 3D printing with CNF as a rheology modifier and reinforcer with formation of interpenetrating double polymer network were obtained after UV curing.Composite hydrogels were formed by replacing ChCl with water.It was found that the introduction of amide groups into the acrylate polymer matrix resulted in an increase in compressive strength.The layered architecture of the 3D printed products provides greater mechanical strength compared to molded products.The structure of the composites was investigated using wide-angle X-ray scattering(WAXS),small-angle X-ray scattering(SAXS),atomic force microscopy(AFM)and polarized light microscopy.These studies suggest that the enhanced mechanical properties of the 3D printed hydrogels are associated with swelling and branching of CNF in the DES,as well as alignment of the filler during extrusion.For comparative analysis,composite hydrogels were also prepared using aqueous solutions of AA and AA/AAm with dispersed CNF.However,the 3D printing process was hampered in this case due to cellulose agglomeration.Mechanical testing revealed the formation of premature microcracks in these samples,which were not observed in composites produced using DES.Cytotoxicity of the composite hydrogels was also tested.The results provide valuable insights into the production of strong(up to 3.4 MPa)homogeneous composite hydrogels using 3D printing with nanocellulose filler.
基金supported financially by the National Natural Science Foundation of China(No.51971212)the Russian Science Foundation(No.19-72-20080)。
文摘Ferromagnetic high damping(FHA)alloys with a wide temperature range from-150℃to 300℃have unique application value in extreme environments.In the present work,the damping behaviors of Fe-21 Ga-xLa(x=0.12 wt.%,0.24 wt.%,0.47 wt.%,1.18 wt.%,and 2.33 wt.%La)alloys have been studied in detail,and a new phenomenological model has been proposed.With the increase of La content,the Laves phase(LaGa_(2))in the matrix increases gradually,and the resistance opposing the domain movement increases as well.Combined with the results of synchrotron radiation X-ray diffraction,neutron diffraction,and magnetic domain observation,the resistance mainly comes from three parts:the average stress related to the lattice distortion of the matrix,the average stress related to the increasing area energy of domain walls(DWs),and the ave rage stress related to the increasing demagnetization energy induced by the Laves phase.Different from the traditional method of reducing internal stress through annealing to improve the damping capacity,the proper internal stress barriers are necessary to Barkhausen jumps to dissipate energy.Therefore,proper doping to balance resistance and mobility of DWs is a reliable way to improve damping capacity.Meanwhile,for Fe-Al and Fe-Cr based Alloys,the new model also has a good fitting effect.This study provides a theoretical and experimental reference for improving the functional properties of ferromagnetic alloys.
文摘We discuss a hardship in synthesis of heaviest super heavy elements in massive nuclei reactions due to the hindrance to complete fusion of reacting nuclei caused on the onset of quasifission process which strongly competes with complete fusion and due to the strong increase of fission yields along the de-excitation cascade of the compound nucleus in comparison with the evaporation residue formation.The hindrance to formation of compound nucleus and evaporation residue is determined by the characteristic of the entrance channel.
文摘Laser irradiation device for the protection of biological objects from the action of ionizing radiation to be used in practice has been manufactured （invention patent RU 2 428 228 C2）. Research of the action of y-radiation itself as well as of the combined action of laser devices on survival, weight, skin and the general mitotic index of the bone marrow cells （mitotic index of all nucleus-containing cells of the bone marrow） of C57BL/6 experimental young mice was carried out. The mice were irradiated with ionizing （whole body irradiation） and laser radiation, separately one by one in a special frame device. Laser radiation in the dose 1 mJ/cm^2 irradiated only the back of a mouse, or both the back and the abdomen of mice. In case of combined irradiation of mice, the time interval between two types of irradiation did not exceed 30 min. First, the mice were exposed to y-radiation then to laser radiation. The method of the laser radiation-protection of biological subjects contributes to an increase in the viability of mice, prevents the damages of skin and also increases the mitotic activity of mice bone marrow cells.
文摘The formamide-titanium oxide interaction mechanism is a research target of great importance for understanding the elementary events of the origin of life: the synthesis of nucleoside bases and formation of biological molecules needed for life. Titanium oxide (TiO2) can act as a strongly adsorbing surface or a catalytic material. In the present study, a comparative molecular dynamics analysis performed to clarify the adsorbing and diffusion properties of liquid formamide on a TiO2 surface in the presence of water molecules. The structural features of the formamide concentration effect (the accumulation of molecules) on a TiO2 surface in the presence and absence of water solvent are cleared up. Modification of the formamide diffusion abilities mediated by a water solvent is observed to correlate with the formamide-water concentration distribution on the surface.
基金supported by the National Natural Science Foundation of China (No. 11675273)the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDA10011102)
文摘A database system,known as the large PMT characterization and instrumentation database system(LPMT-CIDS),was designed and implemented for the Jiangmen Underground Neutrino Observatory(JUNO).The system is based on a Linux+Apache+MySQL+PHP(LAMP)server and focuses on modularization and architecture separation.It covers all the testing stages for the 20-inch photomultiplier tubes(PMTs)at JUNO and provides its users with data storage,analysis,and visualization services.Based on the successful use of the system in the 20-inch PMT testing program,its design approach and construction elements can be extended to other projects.
基金The project supported by the National Natural Science Foundation of China and China National Nuclear Corporation
文摘A twin gridded ionization chamber with dual parameter data acquisition sys-tem is used to study neutron induced charged particle emission reaction.The angulardistribution and cross section of n-particles from the <sup>64</sup>Zn（n,α）<sup>61</sup>Ni reaction are meas-ured at neutron energy 5 MeV.
文摘In 2018,the STAR collaboration collected data from^(96)_(44)Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zr at√^(S)NN=200 Ge V to search for the presence of the chiral magnetic effect in collisions of nuclei.The isobar collision species alternated frequently between 9644 Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zr.In order to conduct blind analyses of studies related to the chiral magnetic effect in these isobar data,STAR developed a three-step blind analysis procedure.Analysts are initially provided a"reference sample"of data,comprised of a mix of events from the two species,the order of which respects time-dependent changes in run conditions.After tuning analysis codes and performing time-dependent quality assurance on the reference sample,analysts are provided a species-blind sample suitable for calculating efficiencies and corrections for individual≈30-min data-taking runs.For this sample,species-specific information is disguised,but individual output files contain data from a single isobar species.Only run-by-run corrections and code alteration subsequent to these corrections are allowed at this stage.Following these modifications,the"frozen"code is passed over the fully un-blind data,completing the blind analysis.As a check of the feasibility of the blind analysis procedure,analysts completed a"mock data challenge,"analyzing data from Au+Au collisions at√^(S)NN=27 Ge V,collected in 2018.The Au+Au data were prepared in the same manner intended for the isobar blind data.The details of the blind analysis procedure and results from the mock data challenge are presented.
基金supported by the National Natural Science Foundation of China(Nos.11775258 and 11575237)the International Scientific and Technological Cooperation Project of Anhui(No.1704e1002207)+2 种基金the Research Initiation Foundation of Anhui Polytechnic University(No.2018YQQ001)the Pre-Research National Natural Science Foundation of China of Anhui Polytechnic University(No.2019yyzr13)the Natural Science Foundation of Anhui(No.1908085QA25)
文摘The superconducting cyclotron SC200 is intended to generate a 200 MeV, 400 nA proton beam for future particle therapy. The internal hot-cathode-type Penning ionization gauge (PIG) ion source for the SC200 is designed for the generation of hydrogen ions. A brief description of the design of ion source and test bench, which are used in SC200, is given in this paper. The ion source has been verified on the test bench, and the results indicated that the designed ion source meets the expected requirements. The lifetime of the filament exceeded 100 h in the test. In addition, the extraction voltage and the gas flow that influence the extracted ion current intensity have been tested in the experiment.
文摘We study the evolution of the dark energy parameter within the scope of a spatially homogeneous and isotropic Friedmann-Robertson-Walker(FRW)model filled with barotropic fluid and dark energy.To obtain the deterministic solution we choose the scale factor a(t)=(√te^(t)),which yields a time-dependent deceleration parameter(DP).In doing so,we consider the case minimally coupled with dark energy to the perfect fluid as well as direct interaction with it.
基金Supported by the National Natural Science Foundation of China under Grant No.19775026the Science Foundation for Nuclear Industry of China under Grant No.Y7197AY509the U.S.Department of Energy under Grant Nos.DE-FG05-88ER40407 and DE-FG03-87ER40323.
文摘Octupole deformation bands built onπh ll/2 orbital in neutron-rich odd-Z 145,147La nuclei have been investigated by measuring the promptγ-rays emitted from the 252Cf source.The alternating parity band structures and strong E1 transitions observed between negative-and positive-parity bands in both nuclei indicate the octupole deformation enhanced by the h ll/2 single proton coupling.According to observed energy displacements the octupole deformation becomes stable at the intermediate spin states.
基金Supported by the National Natural Science Foundation of China under Grant No.19775026the Science Foundation for Nuclear Industry of China under Grant No.Y7197AY509the U.S.Department of Energy under Grant Nos.DE-FG05-88ER0407 and DE-FG03-87ER40323.
文摘High spin states in neutron-rich odd-N ^(145)Ba nucleus have been investigated from study of promptγ-rays in spontaneous fission of^(252)Cf.The alternating parity bands are identified indicating octupole deformation with simplex quantum number s=-i.The ground state band shows signature splitting and inversion at low spin.These collective band structures exhibit the competition and co-existence between symmetric and asymmetric shapes.
文摘A molecular dynamics (MD) simulation is performed on a DNA photolyase to study the conformational behavior of the photoactive cofactor flavin adenine dinucleotide (FAD) inside the enzyme pocket. A DNA photolyase is a highly efficient light-driven enzyme that repairs the UV-induced cyclobutane pyrimidine dimer in damaged DNA. In this work, the FAD conformational and dynamic changes were studied within the total complex structure of a DNA photolyase protein (containing FADH–, MTHF, and DNA molecules) embedded in a water solvent. We aimed to compare the conformational changes of the FAD cofactor and other constituent fragments of the molecular system under consideration. The obtained results were discussed to gain insight into the light-driven mechanism of DNA repair by a DNA photolyase enzyme—based on the enzyme structure, the FAD mobility, and conformation shape.
文摘Several bacterial strains of Actinomycetes belonging to Streptomyces and Arthrobacter genera for the first time were used to study the biotechnology of synthesis of gold and silver nanoparticles.The experimental conditions of gold and silver nanoparticles production by the cells of studied strains in aqueous chloroauric acid(HAuCIq)and in silver nitrate(AgNO3)solutions,respectively,were determined.Concentration and time-dependences of nanoparticle formation were investigated.The complex of optical and analytical methods was used for testing the gold and silver nanoparticles in the bacterial biomass.The TEM(Transmission Electron Microscopy)and XRD(X-ray Diffraction)data in all cases demonstrated the presence of crystals with fcc(face centered cubic)structure.The results obtained show that the Actinomycetes are capable of producing gold and silver nanoparticles of spherical shape extracellularly when exposed to suitable compounds.The particle size distribution shows that the sizes of nanoparticles are in the range of 5 nm to 80 nm.The biomass obtained may be used for industrial as well as medical and pharmaceutical purposes.
文摘The observation of an electroscalar signal during the eclipse of the Sun by the Moon in 2008 was a starting point for the development and creation of the electroscalar field theory. This observation shows that such radiation has a long wavelength, and is longitudinal and extremely penetrating. The properties of the electroscalar and electromagnetic dynamics of a massive charged particle have been studied. An analogy between the linear theory of elasticity and Maxwell electrodynamics is made. The observed spectrum of radiation clarifying peculiar properties. Real sources of electroscalar radiation are determined. In accordance with the principle of least action, the Lagrangian of the electroscalar field and the field force acting on the particle are defined. The spectral expansion of the electroscalar field allowed us to establish that the field is longitudinal and aligned with the wave vector. At the heart of the electroscalar theory, which is compliant with the experimental data, is the four-dimensional scalar potential that describes radial vibrations of the electroscalar field source. The four-vector Maxwell electromagnetic potential and four-scalar potential neither form a single object in the Minkowski space nor interfere and, as a consequence, prove to be independent and unrelated differential relations. Moreover, a strong correlation between the spatial position of the particle and the field components allows and demonstrates a new degree of freedom in the electrodynamics of charged particles.
文摘A new concept is introduced for the classification of “unresolved problems” in the understanding of interactions in thick targets irradiated with relativistic ions: The centre-of-mass energy per nucleon of a hypothetical compound nucleus from a primary interaction, ECM/u, is calculated and correlated with experimental observations in thick target irradia- tions. One observes in various reactions of relativistic primary ions with thick targets that there appears to be a thresh- old energy for reactions leading to “unresolved problems” which lies around ECM/u ~ 150 MeV. All “unresolved prob- lems” are exclusively observed above this threshold, whereas below this threshold no “unresolved problems” are found. A similar threshold at 158 ± 3 MeV exists for massive pion production in nuclear interactions. Hagedorn had proposed this threshold decades ago and it is known as the Hagedorn limit. In this paper we will only mention, but not elaborate on Hagedorn’s theoretical concept any further. Some considerations will be presented and further studies in this field are suggested.
基金Strategic Priority Research Program of Chinese Academy of Sciences(XDB34010000)Guangdong Major Project of Basic and Applied Basic Research(2021B0301030006)+1 种基金National Key R&D Program of China(2018YFA0404402)Frontier Science Key Project of Chinese Academy of Sciences(ZDBS-LY-SLH017)。
文摘Over the past years,experimentalists have launched an expedition to explore the predicted,centered near the double-magic Z=114,N=184 nucleus.With their remarkable e orts,elements from hydrogen up to element 118 at present.The discovery of the superheavy elements o ers the possibilities to study properties of nuclei under extremely strong Coulomb elds and to explore the limits of existence of nuclei.The fusion evaporation reactions induced by low-energy heavy ions are employed for synthesis and study of superheavy isotopes,and the gas-lled recoil separator technique is always used to e ectively separate the produced evaporation residues from projectile-like and target-like products.
基金Strategic Priority Research Program of Chinese Academy of Sciences(XDB34010000)Guangdong Major Project of Basic and Applied Basic Research(2021B0301030006)+1 种基金National Key R&D Program of China(2018YFA0404402)Frontier Science Key Project of Chinese Academy of Sciences(ZDBS-LY-SLH017)。
文摘The new thorium isotope ^(207)Th has been produced in the 5n evaporation channel of the fusion reaction ^(36)Ar+^(176)Hf.The 197-199 MeV ^(36)Ar^(11+)beam with a typical intensity of0.4 pμA was delivered by the Sector Focusing Cyclotron of the Heavy Ion Research Facility in Lanzhou(HIRFL),China.
