搜索到26430篇“ FISSION“的相关文章
Sensitivity impacts owing to the variations in the type of zero-range pairing forces on the fission properties using the density functional theory
2024年
Using the Skyrme density functional theory,potential energy surfaces of^(240)Pu with constraints on the axial quadrupole and octupole deformations(q_(20)and q_(30))were calculated.The volume-like and surface-like pairing forces,as well as a combination of these two forces,were used for the Hartree–Fock–Bogoliubov approximation.Variations in the least-energy fission path,fission barrier,pairing energy,total kinetic energy,scission line,and mass distribution of the fission fragments based on the different forms of the pairing forces were analyzed and discussed.The fission dynamics were studied based on the timedependent generator coordinate method plus the Gaussian overlap approximation.The results demonstrated a sensitivity of the mass and charge distributions of the fission fragments on the form of the pairing force.Based on the investigation of the neutron-induced fission of^(239)Pu,among the volume,mixed,and surface pairing forces,the mixed pairing force presented a good reproduction of the experimental data.
Yang SuZe-Yu LiLi-Le LiuGuo-Xiang DongXiao-Bao WangYong-Jing Chen
Calculation of the energy dependence of fission fragments yields and kinetic energy distributions for neutron-induced ^(235)U fission
2024年
Fission fragments yields and average total kinetic energy are fundamental nuclear data for nuclear energy applications and the study of nuclear devices.Certain fission products,such as ^(95)Zr,^(99)Mo,^(140)Ba,^(144)Ce,and ^(147)Nd,serve as burnup monitors,assessing the number of fissions induced by neutrons on ^(235)U.However,current experimental data for these fission products worldwide are inconsistent,introducing significant uncertainty into related scientific research.In this study,we employed the Potential-driving Model to calculate the independent yields of ^(235)U and evaluate its advantages in such calculations.Additionally,we investigated the energy dependence of independent yields to select important products.Furthermore,we calculated the cumulative yields of ^(95)Zr,^(99)Mo,^(140)Ba,^(144)Ce,and ^(147)Nd,and compared them with existing literature data to explore the energy dependence of fission products for ^(235)U.Given the lack of fission product yield data above 14.8 MeV,we extended our calculated incident neutron energy to 20 MeV,aiming to support future scientific research.The Geant4 physical model does not consider the influence of incident neutron energy on the average total kinetic energy of fission fragments;thus,we introduced the excitation function of the total kinetic energy of fission fragments recommended by Madland et al.,which effectively describes the experimental data of the average total kinetic energy of fragments formed in ^(235)U fission.In this paper,we comprehensively discuss the energy dependence of fission product yields and average total kinetic energy.
Ya-Ning HanZheng WeiYi-Xuan WangDong-Ying HuoPeng-Qi ZhangMing LiJun MaKang WuYong-Guang ZhengYuan HeZhi-Yong DengTian-Zhi JiangXiang-Lin ZhuoJin LiYun ZhangYu ZhangJun-Run WangXiao-Dong SuZe-En Yao
Nanotechnology in Nuclear Reactors: Innovations in Fusion and Fission Power Generation
2024年
This article explores the transformative potential of nanotechnology and MMs(memory metals)in enhancing the design and operation of nuclear reactors,encompassing both fission and fusion technologies.Nanotechnology,with its ability to engineer materials at the atomic scale,offers significant improvements in reactor safety,efficiency,and longevity.In fission reactors,nanomaterials enhance fuel rod integrity,optimize thermal management,and improve in-core instrumentation.Fusion reactors benefit from nanostructured materials that bolster containment and heat dissipation,addressing critical challenges in sustaining fusion reactions.The integration of SMAs(shape memory alloys),or MMs,further amplifies these advancements.These materials,characterized by their ability to revert to a pre-defined shape under thermal conditions,provide self-healing capabilities,adaptive structural components,and enhanced magnetic confinement.The synergy between nanotechnology and MMs represents a paradigm shift in nuclear reactor technology,promising a future of cleaner,more efficient,and safer nuclear energy production.This innovative approach positions the nuclear industry to meet the growing global energy demand while addressing environmental and safety concerns.
Bahman Zohuri
关键词:NANOTECHNOLOGYMMSSMAS
中子诱发^(238)U裂变产额的统一评价
2024年
采用基于Z_(P)模型的裂变产额统一评价方法,开展中子诱发^(238)U裂变产额评价,通过拟合实验数据获得优化的模型参数,基于获得的模型参数计算入射能量为裂变谱(F)和14 MeV(H)的中子诱发^(238)U裂变的独立产额和累积产额,并建立了ENDF/B-VI格式数据库。该评价方法包含了裂变独立产额、累积产额和衰变数据相互关联的物理机制,可以获得自洽的产额数据,解决了传统评价方法产额不自洽的问题,同时可以获得缺失或者缺乏实验数据的产额。与国际现有产额数据库比较,本工作评价的累积产额与实验数据的符合度χ^(2)=7.1(F)和2.9(H),与ENDF/B-VIII.0裂变产额子库的χ^(2)=8.0(F)和57.3(H)、JEFF-3.3裂变产额子库的χ^(2)=57.0(F)和74.2(H)相比,有较好的改进。
李畅刘玲舒能川曹超维宿阳陈永静肖越刘萍
关键词:裂变产额
自然演化碎屑锆石裂变径迹长度影响因素分析
2024年
锆石裂变径迹长度是锆石裂变径迹热年代学研究的一个重要参数。基于不同热背景的沉积盆地样品实测数据,分析锆石裂变径迹的退火行为,探讨锆石裂变径迹长度的影响因素。研究表明,Sk1井样品的裂变径迹长度和径迹与结晶C轴夹角之间具有一定的负相关性,即夹角愈小,径迹长度愈长;反之,夹角愈大,径迹长度愈短。Sk1井样品径迹与结晶C轴夹角主要分布在10°~70°,整体分布较随机;而Ku1井样品多分布于高角度(60°~90°),整体分布不随机。Sk1井锆石裂变径迹在沉积盆地开始退火温度为220℃,深层样品的平均径迹长度为5.02~5.55μm;Ku1井锆石裂变径迹在沉积盆地开始退火温度为170℃,深层样品的平均径迹长度为8.06~8.31μm,高温热背景下Sk1井的锆石裂变径迹开始受到沉积盆地影响的温度高于Ku1井。研究认为锆石裂变径迹在不同热背景下的开始退火温度和退火行为产生的差异是由盆地不同的增温速率导致的。Sk1井的中浅层样品平均径迹长度范围为5.85~8.36μm,Ku1井中浅层样品平均径迹长度为9.21~10.05μm。2口井中浅层样品的最小年龄大于地层年龄,表明未受到沉积盆地的影响,缩短的径迹长度是受到母源区热事件的影响。对锆石裂变径迹的退火行为和径迹长度影响因素的分析对于油气成藏过程以及烃源岩的热演化史研究具有指导意义。
陈鸿蔡长娥罗开通雷超尚文亮
关键词:退火行为
基于瞬态拼接裂变矩阵的耦合型中子动力学算法研发
2024年
在核反应系统的瞬态计算中,通常使用的确定论方法和蒙特卡罗方法不能同时兼备计算精度与计算效率,其中点堆动力学方法无法得到空间上的分布,扩散方法计算速度快但误差较大,输运方法和蒙特卡罗方法虽然精度高但计算效率低。本文在瞬态裂变矩阵和拼接裂变矩阵理论的基础上,提出了瞬态拼接裂变矩阵方法,该方法可精确快速地进行瞬态分析。其中,瞬态裂变矩阵方法是一种可进行输运计算的混合方法,但需大量的计算时间用于生成瞬态裂变矩阵。拼接裂变矩阵方法是一种可高效处理裂变矩阵数据库以及快速计算全堆芯稳态的方法,但未运用于瞬态分析中。本文通过单棒模型以及组件模型的瞬态工况对瞬态拼接裂变矩阵方法进行验证。结果表明,瞬态拼接裂变矩阵方法在稳态和瞬态计算过程与参考解吻合良好,能在61 cup·h时间完成真实时间0.5 s的插棒-提棒的瞬态三维精确解,均方根误差在整个插棒-提棒的瞬态过程中均保持在0.2%以下。
李玥航何东豪刘晓晶潘清泉
关键词:蒙特卡罗方法
基于能量密度泛函理论研究对关联对原子核裂变过程的影响
2024年
以^(239)Pu的中子诱发裂变为例,系统研究了对力形式的不确定性以及对关联强度的不确定性对裂变可观测量的影响,从而揭示了对关联在裂变过程所起的作用。首先使用基于Skyrme有效核力的能量密度泛函理论(DFT)计算了^(240)Pu二维形变空间中的静态裂变位能曲面,在Hartree-Fock-Bogoliubov (HFB)近似中分别使用了体积型、表面型及混合型对力,并测试了不同对力强度的影响;然后基于密度泛函的计算结果,进一步采用含时生成坐标(TDGCM)和高斯重叠近似(GOA)方法开展了^(240)Pu裂变动力学计算。通过分析讨论了对力类型和对力强度变化对裂变过程中相关物理量的影响,发现对力强度的改变在原子核小形变、大形变区域均有明显影响,然而对力类型的改变主要在大形变区域会产生明显差异。原子核的大形变组态会对裂变动力学过程产生比较重要的影响。计算结果表明,不同的对力类型得到的大形变组态会有较为显著的差别,因而合适的对力类型的选取对裂变描述是比较重要的,混合对力在裂变计算中效果最佳。
宿阳李泽宇刘丽乐陈永静王小保
关键词:核裂变密度泛函理论对关联
Apatite Fission-Track Thermochronology in the Tamusu Area,Bayingobi Basin,NW China,and its Geological Significance
2024年
The Bayingobi basin is located in the middle of Central Asia Orogenic Belt,at the intersection of Paleo-Asian Ocean and Tethys Ocean,as well as the junction of multiple tectonic plates.This unique tectonic setting underpins the basin's intricate history of tectonic activity.To unravel the multifaceted tectono-thermal evolution within the southwestern region of the basin and to elucidate the implications of sandstone-hosted uranium mineralization,granitic and clastic rock samples were collected from the Zongnai Mts.uplift and Yingejing depression,and apatite fission track(AFT)dating and thermal history simulation analysis were performed.AFT dating findings reveal that the apparent ages of all samples fall within the range of 244 Ma to 112 Ma.In particular,the bedrock of the Zongnai Mts.and Jurassic detrital apatite fission tracks have undergone complete annealing,capturing the uplift-cooling age.Meanwhile,the AFT ages of Cretaceous detrital rocks are either equivalent to or notably exceed the age of sedimentary strata,signifying the cooling age of the provenance.A comprehensive examination of AFT ages and palaeocurrent direction analyses suggests that the Cretaceous source in the Tamusu area predominantly originated from the central and southern sectors of the Zongnai Mts.uplift.However,at a certain juncture during the Late Early Cretaceous,the Cretaceous provenance expanded to include the northern part of the Zongnai Mts.uplift.Based on the results of thermal history simulations and previous studies,it is considered that the Tamusu area has undergone four distinct tectonic uplift events since the Late Paleozoic.The first is the Late Permian to Early Triassic(260-240 Ma),which is associated with the closure of the Paleo-Asian Ocean and the accretionary orogeny within the Alxa region.The second uplift event took place in the Early Jurassic(190-175 Ma)and corresponded to intraplate orogeny following the closure of the Paleo-Asian Ocean.The third uplift event is the Late Jurassic to Early Cretaceous(160-120 Ma),which
TONG QinlongQIN MingkuanYE Fawang
Korean red ginseng alleviates benign prostatic hyperplasia by dysregulating androgen receptor signaling and inhibiting DRP1-mediated mitochondrial fission
2024年
Panax ginseng(C.A.Mey.)has been traditionally employed in Korea and China to alleviate fatigue and digestive disorders.In particular,Korean red ginseng(KRG),derived from streamed and dried P.ginseng,is known for its anti-aging and anti-inflammatory properties.However,its effects on benign prostatic hyperplasia(BPH),a representative aging-related disease,and the underlying mechanisms remain unclear.This study aims to elucidate the therapeutic effects of KRG on BPH,with a particular focus on mitochondrial dynamics,including fission and fusion processes.The effects of KRG on cell proliferation,apoptosis,and mitochondrial dynamics and morphology were evaluated in a rat model of testosterone propionate(TP)-induced BPH and TP-treated LNCaP cells,with mdivi-1 as a control.The results revealed that KRG treatment reduced the levels of androgen receptors(AR)and prostate-specific antigens in the BPH group.KRG inhibited cell proliferation by downregulating cyclin D and proliferating cell nuclear antigen(PCNA)levels,and it promoted apoptosis by increasing the ratio of B-cell lymphoma protein 2(Bcl-2)-associated X protein(Bax)to Bcl-2 expression.Notably,KRG treatment enhanced the phosphorylation of dynamin-related protein 1(DRP-1,serine 637)compared with that in the BPH group,which inhibited mitochondrial fission and led to mitochondrial elongation.This modulation of mitochondrial dynamics was associated with decreased cell proliferation and increased apoptosis.By dysregulating AR signaling and inhibiting mitochondrial fission through enhanced DRP-1(ser637)phosphorylation,KRG effectively reduced cell proliferation and induced apoptosis.These findings suggest that KRG’s regulation of mitochondrial dynamics offers a promising clinical approach for the treatment of BPH.
HONG Geum-LanKIM Kyung-HyunCHO Sung-PilLEE Hui-JuKIM Yae-JiJUNG Ju-Young
关键词:ANDROGENFISSIONMITOCHONDRIA
磷灰石裂变径迹定年技术原理及地质演化过程的应用
2024年
磷灰石裂变径迹因封闭温度低(60℃~120℃),能记录浅地表冷却过程,在地质领域得到广泛应用。通过总结前人研究资料,介绍磷灰石裂变径迹实验原理、实验数据处理与解释,重点阐述该方法在地质演化过程的应用,包括矿床剥露过程、造山带地质演化、盆地演化过程、古地貌研究及断层活动时间等。该方法是研究地质体低温热历史信息最有效方法之一,但目前仍存在测年过程受人为影响较大、不适合低U或年轻地质体测量、实验周期较长等缺点。因此,为更精确地约束地质体演化过程,仍需结合多种技术手段。
祁翼
关键词:低温热年代学磷灰石裂变径迹地质应用

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