We present an analysis of the xF_3(x,Q^2) structure function and Gross-Llewellyn Smith(GLS) sum rule taking into account the nuclear effects and higher twist correction. This analysis is based on the results presented...We present an analysis of the xF_3(x,Q^2) structure function and Gross-Llewellyn Smith(GLS) sum rule taking into account the nuclear effects and higher twist correction. This analysis is based on the results presented in[N.M. Nath, et al., Indian J. Phys. 90(2016) 117]. The corrections due to nuclear effects predicted in several earlier analysis are incorporated to our results of xF_3(x,Q^2) structure function and GLS sum rule for free nucleon, corrected upto next-next-to-leading order(NNLO) perturbative order and calculate the nuclear structure function as well as sum rule for nuclei. In addition, by means of a simple model we have extracted the higher twist contributions to the nonsinglet structure function xF_3(x,Q^2) and GLS sum rule in NNLO perturbative orders and then incorporated them to our results. Our NNLO results along with nuclear effect and higher twist corrections are observed to be compatible with corresponding experimental data and other phenomenological analysis.展开更多
With three theoretical models of nuclear effects on gluon distribution functions,the differentialcross sections and the total cross sections for associate production of J/ψ and γ with large P_T in high energyp-Fe co...With three theoretical models of nuclear effects on gluon distribution functions,the differentialcross sections and the total cross sections for associate production of J/ψ and γ with large P_T in high energyp-Fe collisions are calculated.展开更多
An improved formula considering the deformation effect for the α-decay half-lives is proposed based on WKB barrier penetrability.Using the quadrupole deformation values of the daughter nuclei obtained from the WS4 an...An improved formula considering the deformation effect for the α-decay half-lives is proposed based on WKB barrier penetrability.Using the quadrupole deformation values of the daughter nuclei obtained from the WS4 and FRDM models in the improved formula,the root mean square deviation(RMSD)between the calculated results and experimental data decreased from 0.456 to 0.413 and 0.415,respectively.Although the improved formula did not significantly reduce the overall RMSD,it produced results that better matched the experimental values for nuclei with larger deformations.Additionally,eXtreme Gradient Boosting(XGBoost)models were employed to further reduce the deviations between the calculated α-decay half-lives and experimental data,with the corresponding RMSDs decreasing from 0.413 to 0.295 and from 0.415 to 0.302,respectively.Furthermore,the improved empirical formula and XGBoost models were used to predict the α-decay half-lives of nuclei with Z=117,118,119,and 120.The results suggest that N=184 is the magic number.展开更多
It is well-known that the equilibrium isotope fractionation of mercury(Hg)includes classical massdependent fractionations(MDFs)and nuclear volume effect(NVE)induced mass-independent fractionations(MIFs).However,the ef...It is well-known that the equilibrium isotope fractionation of mercury(Hg)includes classical massdependent fractionations(MDFs)and nuclear volume effect(NVE)induced mass-independent fractionations(MIFs).However,the effect of the NVE on these kinetic processes is not known.The total fractionations(MDFs+NVEinduced MIFs)of several representative Hg-incorporated substances were selected and calculated with ab initio calculations in this work for both equilibrium and kinetic processes.NVE-induced MIFs were calculated with scaled contact electron densities at the nucleus through systematic evaluations of their accuracy and errors using the Gaussian09 and DIRAC19 packages(named the electron density scaling method).Additionally,the NVE-induced kinetic isotope effect(KIE)of Hg isotopes are also calculated with this method for several representative Hg oxidation reactions by chlorine species.Total KIEs for 202 Hg/^(198)Hg ranging from−2.27‰to 0.96‰are obtained.Three anomalous^(202)Hg-enriched KIEs(δ^(202)Hg/^(198)Hg=0.83‰,0.94‰,and 0.96‰,)caused by the NVE are observed,which are quite different from the classical view(i.e.,light isotopes react faster than the heavy ones).The electron density scaling method we developed in this study can provide an easier way to calculate the NVE-induced KIEs for heavy isotopes and serve to better understand the fractionation mechanisms of mercury isotope systems.展开更多
Extended quark distribution functions are presented obtained by fitting a large amount of experimental data of the l-A DIS process on the basis of an improved nuclear density model. The experimental data of l-A DIS pr...Extended quark distribution functions are presented obtained by fitting a large amount of experimental data of the l-A DIS process on the basis of an improved nuclear density model. The experimental data of l-A DIS processes with A≥ 3 in the region 0.0010 ≤ x ≤ 0.9500 are quite satisfactorily described by using the extended formulae. Our knowledge of the influence of nuclear matter on the quark distributions is deepened.展开更多
An anomalous isotope effect exists in many heavy element isotope systems （e.g., Sr, Gd, Zn, U）. This effect used to be called the ＂odd--even isotope effect＂ because the odd mass number isotopes behave differently ...An anomalous isotope effect exists in many heavy element isotope systems （e.g., Sr, Gd, Zn, U）. This effect used to be called the ＂odd--even isotope effect＂ because the odd mass number isotopes behave differently from the even mass number isotopes. This mass-indepen- dent isotope fractionation driving force, which originates from the difference in the ground-state electronic energies caused by differences in nuclear size and shape, is cur- rently denoted as the nuclear field shift effect （NFSE）. It is found that the NFSE can drive isotope fractionation of some heavy elements （e.g., Hg, T1, U） to an astonishing degree, far more than the magnitude caused by the con- ventional mass-dependent effect （MDE）. For light ele- ments, the MDE is the dominant factor in isotope fractionation, while the NFSE is neglectable. Furthermore, the MDE and the NFSE both decrease as temperatures increase, though at different rates. The MDE decreases rapidly with a factor of 1/T2, while the NFSE decreases slowly with a factor of 1/T. As a result, even at high temperatures, the NFSE is still significant for many heavy element isotope systems. In this review paper, we begin with an introduction of the basic concept of the NSFE, including its history and recent progress, and follow with the potential implications of the inclusion of the NFSE into the kinetic isotope fractionation effect （KIE） and heavy isotope geochronology.展开更多
To investigate equilibrium mercury(Hg)and lead(Pb)isotope fractionation caused by the nuclear volume effect(NVE)in crystals,the electron densities at nuclei(i.e.,|Ψ(0)|2)for Hg-or Pb-bearing crystalline compounds wer...To investigate equilibrium mercury(Hg)and lead(Pb)isotope fractionation caused by the nuclear volume effect(NVE)in crystals,the electron densities at nuclei(i.e.,|Ψ(0)|2)for Hg-or Pb-bearing crystalline compounds were investigated by using the relativistic spin orbit zeroth-order regular approximation(ZORA)method with a three-dimensional periodic boundary condition based on the density functional theory(DFT).Many isotope fractionation factors of crystalline compounds are provided for the first time.Our results show,even at1000℃,NVE-driven Hg and Pb isotope fractionation are meaningfully large,i.e.,range from 0.12‰to 0.49‰(202Hg/^(198)Hg),from-0.20‰to 0.17‰(208Pb/^(206)Pb)and from-0.08‰to 0.06‰(207Pb/^(206) Pb)relative to Hg0 vapor and Pb0 vapor,respectively.Specifically,the fractionations range from-0.06‰to-0.20‰(208Pb/^(206)Pb)and from-0.02‰to-0.08‰(207Pb/^(206)Pb)for Pb2+-bearing species,from 0.10‰to 0.17‰(208Pb/^(206)Pb)and from 0.04‰to 0.06‰(207Pb/^(206)Pb)for Pb4+-bearing species in crystals.All calculated Hg-bearing species in crystals will enrich heavier isotope(202Hg)relative to Hg0 vapor.Meanwhile,Pb4+-bearing species enrich heavier Pb isotopes(208Pb and 207Pb)than Pb^(2+)-bearing species in crystals,which the enrichment can be up to 0.37‰(208-Pb/^(206)Pb)and 0.14‰(207Pb/^(206)Pb)at 1000℃,due to their NVEs are in opposite directions.The NVE-driven MIFs of Hg isotopes,which are compared to the Hg202-Hg198baseline,are up to-0.158‰(ΔNV199Hg),-0.024‰(ΔNV200Hg)and-0.094‰(ΔNV201Hg)relative to Hg0 vapor at5000 C.For all studied Hg-bearing species in crystals,the MIFs of two odd-mass isotopes(i.e.,ΔNV199Hg andΔNV201Hg)will be changed proportionally and their ratio(i.e.,ΔNV199Hg/ΔNV201Hg)will be a constant 1.67.The NVE can also cause mass-independent fractionations for 207Pb and 204 Pb compared to the baseline of 208Pb and 206Pb.The largest NVEdriven MIFs are 0.043‰(ΔNV207Pb)and-0.040‰(ΔNV204Pb)among all the studied species relative to Pb0 vapor at 5000 C.The magnitudes of odd-mass isotope MIF(ΔNV207Pb)and even-mass isotope MIF(ΔNV204Pb)are almost the same but with opposite signs,leading to the MIF ratio of them(i.e.,ΔNV207Pb/ΔNV204Pb)is-1.08.展开更多
1 Introduction In deeper study of HTSC, it is found that Y<sub>1</sub>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub> has an unusualproperty of absorbing hydrogen. The abso...1 Introduction In deeper study of HTSC, it is found that Y<sub>1</sub>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub> has an unusualproperty of absorbing hydrogen. The absorption process could be described by a gen-eral equation （x/2） H<sub>2</sub> + Y<sub>1</sub>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub>→H<sub>x</sub>Y<sub>1</sub>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub>.A structural analysis indicates that absorbed hydrogen is located on the Cu-Osurface and its state change with temperature. As an isotope of hydrogen,deuterium can have simlar effects. Therefore we have experimentally studied展开更多
A dynamic model of DNA molecules which takes into account the interaction of the nearestbase pairs between the different strands is presented.The nonlinear effect and phase transition aresimulated by the nuclear trans...A dynamic model of DNA molecules which takes into account the interaction of the nearestbase pairs between the different strands is presented.The nonlinear effect and phase transition aresimulated by the nuclear transport theory and the method of fractorial moment in high energy physics,re-spectively.The results show that the nonlinear interaction of the nearest base pairs between the differentstrands may play a rule in DNA molecules.展开更多
为探讨低压静电场(low voltage electrostatic field,LVEF)处理对蝴蝶兰切花保鲜效果的影响,该研究以蝴蝶兰切花品种“天堂鸟”为试验对象,探究了低压静电场处理对蝴蝶兰切花瓶插期间观赏品质、理化指标及相关酶活性的变化,并通过低场...为探讨低压静电场(low voltage electrostatic field,LVEF)处理对蝴蝶兰切花保鲜效果的影响,该研究以蝴蝶兰切花品种“天堂鸟”为试验对象,探究了低压静电场处理对蝴蝶兰切花瓶插期间观赏品质、理化指标及相关酶活性的变化,并通过低场核磁共振(low-field nuclear magnetic resonance,LF-NMR)技术分析蝴蝶兰切花的水分迁移和水分流失情况。结果表明:瓶插第28天时,与对照组相比,低压静电场组的蝴蝶兰切花能保持较好的外观形态,其鲜质量和花径分别显著(P<0.05)提高4.88%、4.98%,可溶性糖含量和可溶性蛋白含量分别显著(P<0.05)提高了0.75、4.09 mg/g,相对电导率和丙二醛(malondialdehyde,MDA)含量分别显著(P<0.05)降低了31.53%、21.96 nmol/g,超氧化物歧化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase,POD)和过氧化氢酶(catalase,CAT)的活性峰值分别显著(P<0.05)提高了19.58、20.77、20.21 U/g,同时,结果表明低压静电场处理延缓了蝴蝶兰切花的水分迁移和水分流失现象。综上,低压静电场处理延缓了蝴蝶兰切花的品质劣变,该研究结果可为其他切花的保鲜应用提供一定的理论依据和技术参考。展开更多
基金Support from DAE-BRNS,India,as Major Research Project under Sanction No.2012/37P/36/BRNS/2018 dated 24 Nov.2012
文摘We present an analysis of the xF_3(x,Q^2) structure function and Gross-Llewellyn Smith(GLS) sum rule taking into account the nuclear effects and higher twist correction. This analysis is based on the results presented in[N.M. Nath, et al., Indian J. Phys. 90(2016) 117]. The corrections due to nuclear effects predicted in several earlier analysis are incorporated to our results of xF_3(x,Q^2) structure function and GLS sum rule for free nucleon, corrected upto next-next-to-leading order(NNLO) perturbative order and calculate the nuclear structure function as well as sum rule for nuclei. In addition, by means of a simple model we have extracted the higher twist contributions to the nonsinglet structure function xF_3(x,Q^2) and GLS sum rule in NNLO perturbative orders and then incorporated them to our results. Our NNLO results along with nuclear effect and higher twist corrections are observed to be compatible with corresponding experimental data and other phenomenological analysis.
基金The project supported in part by the National Natural Science Foundation of Chinathe Doctoral Program Foundation of Institution of Higher Education of Chinathe Provincial Natural Science Foundation of Hebei
文摘With three theoretical models of nuclear effects on gluon distribution functions,the differentialcross sections and the total cross sections for associate production of J/ψ and γ with large P_T in high energyp-Fe collisions are calculated.
基金supported by the Joint Funds for the Innovation of Science and Technology,Fujian province(Nos.2021Y9190 and 2021Y9210)National Natural Science Foundation of China(No.12475121)National Key R&D Program of China(Nos.2023YFA1606503 and 2024YFE0109804).
文摘An improved formula considering the deformation effect for the α-decay half-lives is proposed based on WKB barrier penetrability.Using the quadrupole deformation values of the daughter nuclei obtained from the WS4 and FRDM models in the improved formula,the root mean square deviation(RMSD)between the calculated results and experimental data decreased from 0.456 to 0.413 and 0.415,respectively.Although the improved formula did not significantly reduce the overall RMSD,it produced results that better matched the experimental values for nuclei with larger deformations.Additionally,eXtreme Gradient Boosting(XGBoost)models were employed to further reduce the deviations between the calculated α-decay half-lives and experimental data,with the corresponding RMSDs decreasing from 0.413 to 0.295 and from 0.415 to 0.302,respectively.Furthermore,the improved empirical formula and XGBoost models were used to predict the α-decay half-lives of nuclei with Z=117,118,119,and 120.The results suggest that N=184 is the magic number.
基金This paper is supported by Chinese NSF project(42130114)the strategic priority research program(B)of CAS(XDB41000000)the pre-research Project on Civil Aerospace Technologies No.D020202 funded by Chinese National Space Administration(CNSA)。
文摘It is well-known that the equilibrium isotope fractionation of mercury(Hg)includes classical massdependent fractionations(MDFs)and nuclear volume effect(NVE)induced mass-independent fractionations(MIFs).However,the effect of the NVE on these kinetic processes is not known.The total fractionations(MDFs+NVEinduced MIFs)of several representative Hg-incorporated substances were selected and calculated with ab initio calculations in this work for both equilibrium and kinetic processes.NVE-induced MIFs were calculated with scaled contact electron densities at the nucleus through systematic evaluations of their accuracy and errors using the Gaussian09 and DIRAC19 packages(named the electron density scaling method).Additionally,the NVE-induced kinetic isotope effect(KIE)of Hg isotopes are also calculated with this method for several representative Hg oxidation reactions by chlorine species.Total KIEs for 202 Hg/^(198)Hg ranging from−2.27‰to 0.96‰are obtained.Three anomalous^(202)Hg-enriched KIEs(δ^(202)Hg/^(198)Hg=0.83‰,0.94‰,and 0.96‰,)caused by the NVE are observed,which are quite different from the classical view(i.e.,light isotopes react faster than the heavy ones).The electron density scaling method we developed in this study can provide an easier way to calculate the NVE-induced KIEs for heavy isotopes and serve to better understand the fractionation mechanisms of mercury isotope systems.
基金Supported by Natural Science Foundation of China (100775061, 10505016, 10575119)CAS Knowledge Innovation Project(KJCX-SYW-N02)+1 种基金Major State Basic Research Developing Program of China (2007CB815004)Natural Science Foundationof Hebei Province in China (A2005000535, 103143)
文摘Extended quark distribution functions are presented obtained by fitting a large amount of experimental data of the l-A DIS process on the basis of an improved nuclear density model. The experimental data of l-A DIS processes with A≥ 3 in the region 0.0010 ≤ x ≤ 0.9500 are quite satisfactorily described by using the extended formulae. Our knowledge of the influence of nuclear matter on the quark distributions is deepened.
基金funding support from the973 Program(2014CB440904)Chinese NSF projects(41225012,41490635,41530210)
文摘An anomalous isotope effect exists in many heavy element isotope systems （e.g., Sr, Gd, Zn, U）. This effect used to be called the ＂odd--even isotope effect＂ because the odd mass number isotopes behave differently from the even mass number isotopes. This mass-indepen- dent isotope fractionation driving force, which originates from the difference in the ground-state electronic energies caused by differences in nuclear size and shape, is cur- rently denoted as the nuclear field shift effect （NFSE）. It is found that the NFSE can drive isotope fractionation of some heavy elements （e.g., Hg, T1, U） to an astonishing degree, far more than the magnitude caused by the con- ventional mass-dependent effect （MDE）. For light ele- ments, the MDE is the dominant factor in isotope fractionation, while the NFSE is neglectable. Furthermore, the MDE and the NFSE both decrease as temperatures increase, though at different rates. The MDE decreases rapidly with a factor of 1/T2, while the NFSE decreases slowly with a factor of 1/T. As a result, even at high temperatures, the NFSE is still significant for many heavy element isotope systems. In this review paper, we begin with an introduction of the basic concept of the NSFE, including its history and recent progress, and follow with the potential implications of the inclusion of the NFSE into the kinetic isotope fractionation effect （KIE） and heavy isotope geochronology.
基金supported by National Natural Science Foundation of China (NSFC) projects (41703012)Qinghai Science and Technology projects (2018-ZJ-956Q)+2 种基金the supports of the Strategic Priority Research Program (B) of CAS (XDB18010100, XDB41000000)pre-research Project on Civil Aerospace Technologies No. D020202 funded by the Chinese National Space AdministrationNSFC projects (41530210)。
文摘To investigate equilibrium mercury(Hg)and lead(Pb)isotope fractionation caused by the nuclear volume effect(NVE)in crystals,the electron densities at nuclei(i.e.,|Ψ(0)|2)for Hg-or Pb-bearing crystalline compounds were investigated by using the relativistic spin orbit zeroth-order regular approximation(ZORA)method with a three-dimensional periodic boundary condition based on the density functional theory(DFT).Many isotope fractionation factors of crystalline compounds are provided for the first time.Our results show,even at1000℃,NVE-driven Hg and Pb isotope fractionation are meaningfully large,i.e.,range from 0.12‰to 0.49‰(202Hg/^(198)Hg),from-0.20‰to 0.17‰(208Pb/^(206)Pb)and from-0.08‰to 0.06‰(207Pb/^(206) Pb)relative to Hg0 vapor and Pb0 vapor,respectively.Specifically,the fractionations range from-0.06‰to-0.20‰(208Pb/^(206)Pb)and from-0.02‰to-0.08‰(207Pb/^(206)Pb)for Pb2+-bearing species,from 0.10‰to 0.17‰(208Pb/^(206)Pb)and from 0.04‰to 0.06‰(207Pb/^(206)Pb)for Pb4+-bearing species in crystals.All calculated Hg-bearing species in crystals will enrich heavier isotope(202Hg)relative to Hg0 vapor.Meanwhile,Pb4+-bearing species enrich heavier Pb isotopes(208Pb and 207Pb)than Pb^(2+)-bearing species in crystals,which the enrichment can be up to 0.37‰(208-Pb/^(206)Pb)and 0.14‰(207Pb/^(206)Pb)at 1000℃,due to their NVEs are in opposite directions.The NVE-driven MIFs of Hg isotopes,which are compared to the Hg202-Hg198baseline,are up to-0.158‰(ΔNV199Hg),-0.024‰(ΔNV200Hg)and-0.094‰(ΔNV201Hg)relative to Hg0 vapor at5000 C.For all studied Hg-bearing species in crystals,the MIFs of two odd-mass isotopes(i.e.,ΔNV199Hg andΔNV201Hg)will be changed proportionally and their ratio(i.e.,ΔNV199Hg/ΔNV201Hg)will be a constant 1.67.The NVE can also cause mass-independent fractionations for 207Pb and 204 Pb compared to the baseline of 208Pb and 206Pb.The largest NVEdriven MIFs are 0.043‰(ΔNV207Pb)and-0.040‰(ΔNV204Pb)among all the studied species relative to Pb0 vapor at 5000 C.The magnitudes of odd-mass isotope MIF(ΔNV207Pb)and even-mass isotope MIF(ΔNV204Pb)are almost the same but with opposite signs,leading to the MIF ratio of them(i.e.,ΔNV207Pb/ΔNV204Pb)is-1.08.
文摘1 Introduction In deeper study of HTSC, it is found that Y<sub>1</sub>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub> has an unusualproperty of absorbing hydrogen. The absorption process could be described by a gen-eral equation （x/2） H<sub>2</sub> + Y<sub>1</sub>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub>→H<sub>x</sub>Y<sub>1</sub>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub>.A structural analysis indicates that absorbed hydrogen is located on the Cu-Osurface and its state change with temperature. As an isotope of hydrogen,deuterium can have simlar effects. Therefore we have experimentally studied
文摘A dynamic model of DNA molecules which takes into account the interaction of the nearestbase pairs between the different strands is presented.The nonlinear effect and phase transition aresimulated by the nuclear transport theory and the method of fractorial moment in high energy physics,re-spectively.The results show that the nonlinear interaction of the nearest base pairs between the differentstrands may play a rule in DNA molecules.
文摘废物桶中基体材料的存在限制了主动质询系统对特殊核材料(Special Nuclear Material,SNM)质量测量的准确性,确保核保障测量结果不受基体材料的影响至关重要。因此,考虑到单位质量缓发中子计数率随SNM质量增加的变化,本文在传统校正方法的基础上开发了一种新的基体校正方法。为了验证新方法的有效性,利用Geant4工具包构建了WM3210 PAN Shuffler系统模型,针对常见的基体材料开展了校正算法研究。结果表明,对于不同富集度以及分布状态的U_(3)O_(8)材料,传统校正方法与新校正方法均可以有效地降低基体材料对核材料质量测量的影响。对于U_(3)O_(8)材料位于基体中心的情况,新校正方法得到的^(235)U质量平均相对偏差为13.6%,而传统方法的相对偏差为23.8%;对于U_(3)O_(8)材料均匀弥散在基体中的情况,新校正方法得到的^(235)U质量平均相对偏差为7.78%,而传统方法的相对偏差为20.0%。表明新方法比传统方法表现出更好的校正能力。
