2011 Vol. 28, No. 1
Display Method:
2011, 28(1): 1-22.
doi: 10.11804/NuclPhysRev.28.01.001
Abstract:
We present a review of the recent progress of theoretical models on the description of the superheavy nucleus formation in heavy ion collisions. Two sorts of reactions that are the fusionevaporation mechanism and the massive damped collisions to produce superheavy nuclei are discussed. Problems and further improvements of the capture of colliding partners, the formation of compound nucleus and the deexcitation process are pointed out. Possible combinations for the synthesis of the superheavy nuclei in between the roducts of the cold fusion and 48Ca induced reactions are proposed by the calculations based on the dinuclear system model and also compared with other
approaches. The synthesis of neutronrich heavy isotopes near subshell closure N=162 via transfer reactions in the damped collisions of two actinides and the influence of shell closure on the production of heavy isotopes are investigated. Prospective possibility to reach superheavy nuclei near N=184 via neutronrich radioactive beams of high intensity in the future is discussed.
We present a review of the recent progress of theoretical models on the description of the superheavy nucleus formation in heavy ion collisions. Two sorts of reactions that are the fusionevaporation mechanism and the massive damped collisions to produce superheavy nuclei are discussed. Problems and further improvements of the capture of colliding partners, the formation of compound nucleus and the deexcitation process are pointed out. Possible combinations for the synthesis of the superheavy nuclei in between the roducts of the cold fusion and 48Ca induced reactions are proposed by the calculations based on the dinuclear system model and also compared with other
approaches. The synthesis of neutronrich heavy isotopes near subshell closure N=162 via transfer reactions in the damped collisions of two actinides and the influence of shell closure on the production of heavy isotopes are investigated. Prospective possibility to reach superheavy nuclei near N=184 via neutronrich radioactive beams of high intensity in the future is discussed.
2011, 28(1): 23-35.
doi: 10.11804/NuclPhysRev.28.01.023
Abstract:
The present status of the chemical properties investigation for superheavy elements was described in this paper. The synthesis of superheavy elements and the experimental techniques used in stu dies on the gas phase chemistry of superheavy elements were briefly introduced. The current experimental studies about the gaschromatography of Rf， Db， Sg， Bh， Hs and element 112 were discussed in detail. Finally， the development of synthesis of superheavy elements and the study on gas phase chemical properties of superheavy elements in China were prospected.
The present status of the chemical properties investigation for superheavy elements was described in this paper. The synthesis of superheavy elements and the experimental techniques used in stu dies on the gas phase chemistry of superheavy elements were briefly introduced. The current experimental studies about the gaschromatography of Rf， Db， Sg， Bh， Hs and element 112 were discussed in detail. Finally， the development of synthesis of superheavy elements and the study on gas phase chemical properties of superheavy elements in China were prospected.
2011, 28(1): 36-40.
doi: 10.11804/NuclPhysRev.28.01.036
Abstract:
Since the BaBar Collaboration announced a new hadron Y(2175) observed in the f0(980) invariant mass spectrum of e+e-→ f0(980), both BES and Belle confirmed BaBar’s observation. Meanwhile, the theorist also carries out the study to reveal the underlying properties of Y(2175). In this review paper, we give a detailed review of the present experimental and theoretical statues of Y(2175). In terms of the published experimental data of Y(2175), we also discuss the possibility of searching for other enhancement structures
after 2175 MeV in the f0(980) invariant mass spectrum.
Since the BaBar Collaboration announced a new hadron Y(2175) observed in the f0(980) invariant mass spectrum of e+e-→ f0(980), both BES and Belle confirmed BaBar’s observation. Meanwhile, the theorist also carries out the study to reveal the underlying properties of Y(2175). In this review paper, we give a detailed review of the present experimental and theoretical statues of Y(2175). In terms of the published experimental data of Y(2175), we also discuss the possibility of searching for other enhancement structures
after 2175 MeV in the f0(980) invariant mass spectrum.
2011, 28(1): 41-43.
doi: 10.11804/NuclPhysRev.28.01.041
Abstract:
The E-GOS（E-Gamma Over Spin）curves were used to investigate the structure evolution in the oddA nuclei around A≈110 as a function of spin. The result shows that there is a clear transition from vibration to rotation while increasing spin.
The E-GOS（E-Gamma Over Spin）curves were used to investigate the structure evolution in the oddA nuclei around A≈110 as a function of spin. The result shows that there is a clear transition from vibration to rotation while increasing spin.
2011, 28(1): 44-50.
doi: 10.11804/NuclPhysRev.28.01.044
Abstract:
In this article， the qualities of Wigner function and the corresponding stationary perturbation theory are introduced and applied to one dimensional infinite potential well and onedimensional harmonic oscillator， and then the particular Wigner function of onedimensional infinite potential well is specified and a special constriction effect in its pure state Wigner function is discovered， to which， simultaneously， a detailed and reasonable explanation is elaborated from the perspective of uncertainty principle. Ultimately， the amendment of Wigner function and energy of onedimensional infinite potential well and one dimensional harmonic oscillator under perturbation are calculated according to stationary phase space perturbation theory.
In this article， the qualities of Wigner function and the corresponding stationary perturbation theory are introduced and applied to one dimensional infinite potential well and onedimensional harmonic oscillator， and then the particular Wigner function of onedimensional infinite potential well is specified and a special constriction effect in its pure state Wigner function is discovered， to which， simultaneously， a detailed and reasonable explanation is elaborated from the perspective of uncertainty principle. Ultimately， the amendment of Wigner function and energy of onedimensional infinite potential well and one dimensional harmonic oscillator under perturbation are calculated according to stationary phase space perturbation theory.
2011, 28(1): 51-54.
doi: 10.11804/NuclPhysRev.28.01.051
Abstract:
In this paper, we analyze GrossPitaevskii equation which describes the dynamics of a bright soliton in trapped atomic BoseEinstein condensates, and obtain the exact bright soliton solution of GrossPitaevskii equation in sphericallysymmetric nonharmonic trap.
In this paper, we analyze GrossPitaevskii equation which describes the dynamics of a bright soliton in trapped atomic BoseEinstein condensates, and obtain the exact bright soliton solution of GrossPitaevskii equation in sphericallysymmetric nonharmonic trap.
2011, 28(1): 55-57.
doi: 10.11804/NuclPhysRev.28.01.055
Abstract:
The mass resolving power of ISOL’s spectrometer for Beijing Radioactive Ionbeam Facilities project is 20000， which requires the field uniformity of the magnet better than 1×10-5. To achieve such a high uniformity field，field optimize is indispensable. This paper presents the design method，manufacture techniques and experiment results of surface coils，which are set on pole face of a dipole to improve the magnetic field homogeneity. The integral field uniformity with surface coil is optimized to 3×10-5 from 5×10-4，which is improved roughly an order of magnitude.
The mass resolving power of ISOL’s spectrometer for Beijing Radioactive Ionbeam Facilities project is 20000， which requires the field uniformity of the magnet better than 1×10-5. To achieve such a high uniformity field，field optimize is indispensable. This paper presents the design method，manufacture techniques and experiment results of surface coils，which are set on pole face of a dipole to improve the magnetic field homogeneity. The integral field uniformity with surface coil is optimized to 3×10-5 from 5×10-4，which is improved roughly an order of magnitude.
2011, 28(1): 58-62.
doi: 10.11804/NuclPhysRev.28.01.058
Abstract:
The quench detection system for SuperFRS superferric dipole prototype magnet of FAIR has been designed and built. The balance bridge was used to detect quench signal. In order to avoid blind zone of quench detection， two independent bridges were used. NI PXI7830R FPGA was used to implement filter to quench signal and algorithm of quench decision and to produce quench trigger signal. Presample technique was used in quench data acquisition. The data before and after quench could be recorded for analysis later. The test result indicated that the quench of the dipole’s superconducting coil could be reliably detected by the quench detection module.
The quench detection system for SuperFRS superferric dipole prototype magnet of FAIR has been designed and built. The balance bridge was used to detect quench signal. In order to avoid blind zone of quench detection， two independent bridges were used. NI PXI7830R FPGA was used to implement filter to quench signal and algorithm of quench decision and to produce quench trigger signal. Presample technique was used in quench data acquisition. The data before and after quench could be recorded for analysis later. The test result indicated that the quench of the dipole’s superconducting coil could be reliably detected by the quench detection module.
2011, 28(1): 63-67.
doi: 10.11804/NuclPhysRev.28.01.063
Abstract:
In the classical mechanics frame and the dipole approximation the particle motion equation in bent crystal is reduced to the pendulum equation with a constant momentum by using the sinesquared potential.The phase planar properties are analysed by means of Jacobian elliptic function and the elliptic integral. The maximum deflected energy, the dechanneling factor and the dechanneled length are derived. The results show that the extrated efficiency is 70% for a proton beam with energy E=1.0 GeV moved in the channel on Si(110) if a radius of curvature R=1 m; and dechanneled length is of the order of μm for the particles with MeV energy; the dechanneled length is above 1 meter for the particle with TeV energy.
In the classical mechanics frame and the dipole approximation the particle motion equation in bent crystal is reduced to the pendulum equation with a constant momentum by using the sinesquared potential.The phase planar properties are analysed by means of Jacobian elliptic function and the elliptic integral. The maximum deflected energy, the dechanneling factor and the dechanneled length are derived. The results show that the extrated efficiency is 70% for a proton beam with energy E=1.0 GeV moved in the channel on Si(110) if a radius of curvature R=1 m; and dechanneled length is of the order of μm for the particles with MeV energy; the dechanneled length is above 1 meter for the particle with TeV energy.
2011, 28(1): 68-70.
doi: 10.11804/NuclPhysRev.28.01.068
Abstract:
In this paper，A MICROMEGAS(MicroMeshGaseous Structure) detector with the amplification gap defined by stretching nylon fishing lines has been described . And its count plateau， gas gain and energy resolution in the condition of a 55Fe Xray source and ArCO2 (10%) mixture gases are measured as functions of mesh voltage. The count plateau approaches 280 V at the count rate of 103 Hz. The discharge rate is less than 10－4 when the gas gain is up to 104. The energy resolution is 30% (FWHM) based on －800 V mesh voltage. The position resolution is less than 120 μm at the condition of the sensitive area (50 mm×50 mm) Printed Circuit Boards (PCB) and its strip pitch of 400 μm. The results can satisfy the basic demand of MICROMEGAS detector preliminary design.
In this paper，A MICROMEGAS(MicroMeshGaseous Structure) detector with the amplification gap defined by stretching nylon fishing lines has been described . And its count plateau， gas gain and energy resolution in the condition of a 55Fe Xray source and ArCO2 (10%) mixture gases are measured as functions of mesh voltage. The count plateau approaches 280 V at the count rate of 103 Hz. The discharge rate is less than 10－4 when the gas gain is up to 104. The energy resolution is 30% (FWHM) based on －800 V mesh voltage. The position resolution is less than 120 μm at the condition of the sensitive area (50 mm×50 mm) Printed Circuit Boards (PCB) and its strip pitch of 400 μm. The results can satisfy the basic demand of MICROMEGAS detector preliminary design.
2011, 28(1): 71-77.
doi: 10.11804/NuclPhysRev.28.01.071
Abstract:
Because of the existence of supercooling in a droplet formation chamber, the hydrogen microspheres are still in liquid phase even though their temperature is lower than the triplepoint temperature. This may cause the droplets to shatter in the vacuum injection capillary. Based on the knowledge about supercooling of liquid hydrogen, we have done a thermodynamic simulation of the droplets in the droplet formation chamber, and theoretically suggested the optimal working conditions under which the droplets will most properly nucleate to solid pellets. The suggested working conditions are that the heliumgas pressure and the hydrogen vapor pressure in the droplet formation chamber are kept as low as possible, and the droplet formation chamber should be noless than 6 cm in the length.
Because of the existence of supercooling in a droplet formation chamber, the hydrogen microspheres are still in liquid phase even though their temperature is lower than the triplepoint temperature. This may cause the droplets to shatter in the vacuum injection capillary. Based on the knowledge about supercooling of liquid hydrogen, we have done a thermodynamic simulation of the droplets in the droplet formation chamber, and theoretically suggested the optimal working conditions under which the droplets will most properly nucleate to solid pellets. The suggested working conditions are that the heliumgas pressure and the hydrogen vapor pressure in the droplet formation chamber are kept as low as possible, and the droplet formation chamber should be noless than 6 cm in the length.
2011, 28(1): 78-82.
doi: 10.11804/NuclPhysRev.28.01.078
Abstract:
The determination of cosmogenic 53Mn concentrations found in terrestrial formations has many interesting applications for Earth Sciences. With Accelerator Mass Spectrometry (AMS) it should be possible to detect minute amounts of 53Mn. The situation of international research of 53Mn AMS measurement and applications are presented. The AMS measurement method of 53Mn at China Institute of Atomic Energy and its applications prospect are to be explored.
The determination of cosmogenic 53Mn concentrations found in terrestrial formations has many interesting applications for Earth Sciences. With Accelerator Mass Spectrometry (AMS) it should be possible to detect minute amounts of 53Mn. The situation of international research of 53Mn AMS measurement and applications are presented. The AMS measurement method of 53Mn at China Institute of Atomic Energy and its applications prospect are to be explored.
2011, 28(1): 83-87.
doi: 10.11804/NuclPhysRev.28.01.083
Abstract:
A series of shielding analyses have been performed to estimate the material composition and optimum thickness required for a new radiation shield with various rareearth doped polymer and heavy metal mixtures. The neutron and γ photon fluxes have been calculated by Monte Carlo NParticle(MCNP) transport code. The results indicate that the relative fluxes of γ photon and neutron in both traditional and new composite materials follow an exponential decay rule with the distance of penetration. It can be seen that the composite material consisting of rareearth doped polymer and heavy metal has stronger neutron shielding performance than leadboron polyethylene, but weaker γ shielding effectiveness than WNi alloy. It is also found that materials with more components of rare earth elements don’t always provide better neutron shielding performance.
A series of shielding analyses have been performed to estimate the material composition and optimum thickness required for a new radiation shield with various rareearth doped polymer and heavy metal mixtures. The neutron and γ photon fluxes have been calculated by Monte Carlo NParticle(MCNP) transport code. The results indicate that the relative fluxes of γ photon and neutron in both traditional and new composite materials follow an exponential decay rule with the distance of penetration. It can be seen that the composite material consisting of rareearth doped polymer and heavy metal has stronger neutron shielding performance than leadboron polyethylene, but weaker γ shielding effectiveness than WNi alloy. It is also found that materials with more components of rare earth elements don’t always provide better neutron shielding performance.
2011, 28(1): 88-96.
doi: 10.11804/NuclPhysRev.28.01.088
Abstract:
Cosmic radiation， particularly the highenergy heavyion radiation， may cause serious injury on living organism. Therefore， it is one of critical restriction factor in Manned Spaceflight. Studies show that highenergy heavy ions interacting with the shielding materials can produce numerous kinds of fragments and secondaries. These particles have a direct impact on evaluation of shielding properties of different shielding materials， the optimal shielding structure design and lowdose evaluation after shielding materials. From perspectives of divisions of cosmic rays and passive shielding methods， this paper introduces the groundbased research of shielding materials. The passive shielding method was discussed, based on the experimental data of the total cross sections and fragment（production） cross sections of the aspects of different heavy ions with approximately same energy and 56Fe， 28Si heavy ions with different energies on H， C， CH2， Al and Cu radiation shielding materials. In addition， the fragment fluency distribution， the average LET distribution and the dose reduction per particle of 510 MeV/u 56Fe in different depth of CH2 material were also discussed.
Cosmic radiation， particularly the highenergy heavyion radiation， may cause serious injury on living organism. Therefore， it is one of critical restriction factor in Manned Spaceflight. Studies show that highenergy heavy ions interacting with the shielding materials can produce numerous kinds of fragments and secondaries. These particles have a direct impact on evaluation of shielding properties of different shielding materials， the optimal shielding structure design and lowdose evaluation after shielding materials. From perspectives of divisions of cosmic rays and passive shielding methods， this paper introduces the groundbased research of shielding materials. The passive shielding method was discussed, based on the experimental data of the total cross sections and fragment（production） cross sections of the aspects of different heavy ions with approximately same energy and 56Fe， 28Si heavy ions with different energies on H， C， CH2， Al and Cu radiation shielding materials. In addition， the fragment fluency distribution， the average LET distribution and the dose reduction per particle of 510 MeV/u 56Fe in different depth of CH2 material were also discussed.
2011, 28(1): 97-102.
doi: 10.11804/NuclPhysRev.28.01.097
Abstract:
Energy deposition distribution is very important to study radiotherapy or radioprotection. The *F8 method of MCNP program counts the energy loss of photon and electron together. Only real grid is allowed to *F8, so its computation efficiency is low. This paper gives a new calculation method for energy deposition of photon. Because the energy deposition of photon is accomplished by secondary electron, only electron is counted in the new method. The real collision of the electron is counted by the new method, whereas *F8 only counts the information of particle across the interface. Moreover, virtual grid is allowed in the new method. With real grid, the new method has the same precision and efficiency as *F8. If virtual grid is adopted by the new method, although the precision is slightly down, the efficiency is greatly increased.
Energy deposition distribution is very important to study radiotherapy or radioprotection. The *F8 method of MCNP program counts the energy loss of photon and electron together. Only real grid is allowed to *F8, so its computation efficiency is low. This paper gives a new calculation method for energy deposition of photon. Because the energy deposition of photon is accomplished by secondary electron, only electron is counted in the new method. The real collision of the electron is counted by the new method, whereas *F8 only counts the information of particle across the interface. Moreover, virtual grid is allowed in the new method. With real grid, the new method has the same precision and efficiency as *F8. If virtual grid is adopted by the new method, although the precision is slightly down, the efficiency is greatly increased.
2011, 28(1): 103-108.
doi: 10.11804/NuclPhysRev.28.01.103
Abstract:
The error caused by leaf sequencing often leads to planning of IntensityModulated Radiation Therapy(IMRT) arrange system couldn’t meet clinical demand. The optimization approach in this paper can reduce this error and improve efficiency of planmaking effectively. Conjugate Gradient algorithm was used to optimize segment weight and readjust segment shape， which could minimize the error anteriorposterior leaf sequencing eventually. Frequent clinical cases were tasted by precise radiotherapy system， and then compared DoseVolume histogram between target area and organ at risk as well as isodose line in computed tomography(CT) film， we found that the effect was improved significantly after optimizing segment weight. Segment weight optimizing approach based on Conjugate Gradient method can make treatment planning meet clinical request more efficiently， so that has extensive application perspective.
The error caused by leaf sequencing often leads to planning of IntensityModulated Radiation Therapy(IMRT) arrange system couldn’t meet clinical demand. The optimization approach in this paper can reduce this error and improve efficiency of planmaking effectively. Conjugate Gradient algorithm was used to optimize segment weight and readjust segment shape， which could minimize the error anteriorposterior leaf sequencing eventually. Frequent clinical cases were tasted by precise radiotherapy system， and then compared DoseVolume histogram between target area and organ at risk as well as isodose line in computed tomography(CT) film， we found that the effect was improved significantly after optimizing segment weight. Segment weight optimizing approach based on Conjugate Gradient method can make treatment planning meet clinical request more efficiently， so that has extensive application perspective.
2011, 28(1): 109-113.
doi: 10.11804/NuclPhysRev.28.01.109
Abstract:
The tolerance of the normal skin to the acute radiation injury reaction induced by heavy ion beams has been studied experimentally. The experimental pigs were injected with 1.2 mg/kg ketamine in 10 min before irradiation and were irradiated with 0， 12 ， 21 and 27 Gy 12C6+ ion at a dose rate of 1.2 Gy/min at the Heavy Ion Research Facility in Lanzhou（HIRFL）. The total radiation dose was finished by 3 times at Bragg Peak Region of Heavy Ion Beams.The radiation fields of skin were taken photo and performed biopsy. The contaneous tissues of radiation fields were stained by HE and examined histopatholo gical changes every seven days after irradiation. The results indicated that the cutaneous appearance reaction became more faster with radiation dosage rising and presented with swollen， melanin forming and so on after irradiated by the carbon ions at different dosage. The Pathological examination showed noticeable changes in histological and structural of experimental pigs skin， such as atrophy， vacuolation， denaturation and arranged irregularly in epithelial cells. Furthermore， the time for return to normality became longer with the increasing of radiation dosage. All indexes demonstrated correlation between the does and effects. It is concluded that the irradiation of heavy ion beams to normal skin is security when the radiation dose range is about 0—27 Gy.
The tolerance of the normal skin to the acute radiation injury reaction induced by heavy ion beams has been studied experimentally. The experimental pigs were injected with 1.2 mg/kg ketamine in 10 min before irradiation and were irradiated with 0， 12 ， 21 and 27 Gy 12C6+ ion at a dose rate of 1.2 Gy/min at the Heavy Ion Research Facility in Lanzhou（HIRFL）. The total radiation dose was finished by 3 times at Bragg Peak Region of Heavy Ion Beams.The radiation fields of skin were taken photo and performed biopsy. The contaneous tissues of radiation fields were stained by HE and examined histopatholo gical changes every seven days after irradiation. The results indicated that the cutaneous appearance reaction became more faster with radiation dosage rising and presented with swollen， melanin forming and so on after irradiated by the carbon ions at different dosage. The Pathological examination showed noticeable changes in histological and structural of experimental pigs skin， such as atrophy， vacuolation， denaturation and arranged irregularly in epithelial cells. Furthermore， the time for return to normality became longer with the increasing of radiation dosage. All indexes demonstrated correlation between the does and effects. It is concluded that the irradiation of heavy ion beams to normal skin is security when the radiation dose range is about 0—27 Gy.
2011, 28(1): 114-117.
doi: 10.11804/NuclPhysRev.28.01.114
Abstract:
Effect of the modeled microgravity (MMG) on heavy ioninduced lymphocytes DNA repair by using single cell gel electrophoresis (SCGE) has been studied. The results showed that residual DNA damage induced by Ne ions irradiation increased more in cultures incubated in MMG than in 1 g， which indicated that MMG incubation after Ne ions irradiation reduce the DNA damage repair capacity.
Effect of the modeled microgravity (MMG) on heavy ioninduced lymphocytes DNA repair by using single cell gel electrophoresis (SCGE) has been studied. The results showed that residual DNA damage induced by Ne ions irradiation increased more in cultures incubated in MMG than in 1 g， which indicated that MMG incubation after Ne ions irradiation reduce the DNA damage repair capacity.
2011, 28(1): 118-121.
doi: 10.11804/NuclPhysRev.28.01.118
Abstract:
Human breast cancer cell line MCF7 was irradiated with 4 Gy Xray， collected at 0， 2， 4， 8， 16， 24， 48， 72, 144 h after irradiation， respectively. Whole genome DNA including mtDNA were extracted at each time point， and amplified by polymerase chain reaction(PCR). Then the PCR product was subjected to BSAXI digestion， all of digestion product then underwent a brief electrophoresis. Results showed D310 mutation can be induced by 4 Gy Xray irradiation and D310 mutation can overwhelm the normal phenotype 144 h after irradiation.
Human breast cancer cell line MCF7 was irradiated with 4 Gy Xray， collected at 0， 2， 4， 8， 16， 24， 48， 72, 144 h after irradiation， respectively. Whole genome DNA including mtDNA were extracted at each time point， and amplified by polymerase chain reaction(PCR). Then the PCR product was subjected to BSAXI digestion， all of digestion product then underwent a brief electrophoresis. Results showed D310 mutation can be induced by 4 Gy Xray irradiation and D310 mutation can overwhelm the normal phenotype 144 h after irradiation.
2011, 28(1): 122-125.
doi: 10.11804/NuclPhysRev.28.01.122
Abstract:
To evaluate inactive and mutagenic effects of carbon beam at different LET， the inactivation cross section and mutation cross section induced by carbon beams of different LET values were investigated in a red yeast strain Rhodotorula glutinis AY 91015. It was found that the maximum inactivation cross section of 4.37μm2 , which was very close to the average nucleus cross section, was at LET of 120.0 keV/μm. The maximum mutation cross section was at LET of 96.0 keV/μm. Meanwhile， the highest mutagenicity of carbon ion was found around 58.2 keV/μm. It implied that the most efficient LET to induce mutation in survival yeasts was 58.2 keV/μm， which corresponded to energy of 35 MeV/u carbon beam. The most effective carbon beam to induce inactivation and mutation located at different energy region.
To evaluate inactive and mutagenic effects of carbon beam at different LET， the inactivation cross section and mutation cross section induced by carbon beams of different LET values were investigated in a red yeast strain Rhodotorula glutinis AY 91015. It was found that the maximum inactivation cross section of 4.37μm2 , which was very close to the average nucleus cross section, was at LET of 120.0 keV/μm. The maximum mutation cross section was at LET of 96.0 keV/μm. Meanwhile， the highest mutagenicity of carbon ion was found around 58.2 keV/μm. It implied that the most efficient LET to induce mutation in survival yeasts was 58.2 keV/μm， which corresponded to energy of 35 MeV/u carbon beam. The most effective carbon beam to induce inactivation and mutation located at different energy region.
2011, 28(1): 126-129.
doi: 10.11804/NuclPhysRev.28.01.126
Abstract:
Nucleoli is the sites for ribosome synthesis and processing， however， recent approaches have revealed that it is also involved in variety of cellular processes， especially the cellular stress response. As sensors， nucleoli regulate the localization of nucleolar proteins， such as (Alternate Reading Frame， ARF)， and the activation of key factors， such as P53， and consequently mediate the cellular stress response. In this paper， recent progress in the studies on nucleolar functions in cellular stress response to radiation is reviewed.
Nucleoli is the sites for ribosome synthesis and processing， however， recent approaches have revealed that it is also involved in variety of cellular processes， especially the cellular stress response. As sensors， nucleoli regulate the localization of nucleolar proteins， such as (Alternate Reading Frame， ARF)， and the activation of key factors， such as P53， and consequently mediate the cellular stress response. In this paper， recent progress in the studies on nucleolar functions in cellular stress response to radiation is reviewed.
2011, 28(1): 130-134.
doi: 10.11804/NuclPhysRev.28.01.130
Abstract:
The spacetime neutron multiplication formula was established by introducing the concept of spacetime to the neutron multiplication formula. Because of the rather long computing time by using the formula, the solution of spacetime neutron multiplication formula is optimized which is efficient and accurate. The new method can be used to study the reactor with dynamic change in reactivity. It can be also used for studying the process of startup, outage and powerdrawn operation, which is of great importance to the safety analysis of the mini nuclear reactor.
The spacetime neutron multiplication formula was established by introducing the concept of spacetime to the neutron multiplication formula. Because of the rather long computing time by using the formula, the solution of spacetime neutron multiplication formula is optimized which is efficient and accurate. The new method can be used to study the reactor with dynamic change in reactivity. It can be also used for studying the process of startup, outage and powerdrawn operation, which is of great importance to the safety analysis of the mini nuclear reactor.
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