Subjects: Nuclear Science and Technology >> Radiation Physics and Technology submitted time 2024-05-01
Hua Leiming
Lu Fei
Su Jun
Shen Yangping
Jin Shilun
Yang Guochun
Li Zhihong
Guo Bing
Liu Longxiang
Cao Xiguang
Abstract： The 𝛽-Oslo experimental method provides an important investigative tool for examining the properties of radioactive nuclides in highly excited states and exploring the nucleosynthesis process for elements ranging from iron to uranium. This paper introduces a novel data processing technique designed to eliminate the impact of 𝛽-decay electrons on the detection of nuclear 𝛾 de-excitation within 𝛽-Oslo experiments, accurately unfolding the observed 𝛾-ray spectra. Utilizing a comprehensive detector response function matrix for 𝛾 rays and decay electrons, this method combines column-pivotal elimination and iterative step-by-step inverse solution approaches to determine the true incident 𝛾 spectrum. The reliability and validity of the proposed method have been substantiated through extensive simulations and inverse calculations.
Subjects: Physics >> Nuclear Physics submitted time 2024-03-11
Abstract： Fusion triple product represents a crucial parameter for evaluating the potential of self-sustained fusion nuclear reactions. It employs the product of three physical properties: the fuel nuclei number density ($n$), plasma confinement time ($τ_ mathrm{E}$) and fuel temperature ($T$) to establish a condition for assessing the feasibility of achieving self-sustained nuclear fusion. This study considers a fusion reaction system using $^{6}$Li-D as nuclear fuel, neglects cyclotron radiation, incorporates the impact of relativistic effects on bremsstrahlung radiation and the impact of recycled energy on the energy gain factor $Q$. Based on this foundation, the minimum triple product ($n_ mathrm{i}Tτ_ mathrm{E}$= SI{4.9e23}{ per cubic meter kilo electronvolt second}) is calculated for the $^{6}$Li-D reaction to yield energy gain of Q=1. These results show that although the $^{6}$Li-D fusion reaction can achieve a positive energy gain but the condition required for the $^6$Li-D fusion reaction is more difficult than the D-T fusion reaction.
Subjects: Physics >> Nuclear Physics submitted time 2024-01-09
J. Hu
Z.Y. Han
Y.J. Li
Z.H. Li
G. Lian
Y.P. Shen
S.Q. Yan
S. Zeng
B. Guo
W.P. Liu
Z. Bai
B.L. Jia
S.L. Jin
J.B. Ma
P. Ma
S.B. Ma
S.W. Xu
Y.Y. Yang
N.T. Zhang
X.D. Tang
Abstract： In Orgueil meteorites, an exceptionally high 22Ne/20Ne abundance ratio or even nearly pure 22Ne is ob#2;served, which is the so-called Ne extraordinary problem. Fossil material of extinct 22Na is believed to be the origin of extraordinary 22Ne, these 22Na nuclides were trapped in grains and incorporated into meteorites in stellar explo#2;sive event. Supernovae and neon-rich novae are the primary events, which are responsible for the production of 22Na through the explosive hydrogen burning process. 22Na(p, γ)23Mg and 19Ne(α, p) 22Na are two crucial reactions in the so-called NeNa-MgAl cycle and the rapid-proton process, which lead to the fast nucleosynthesis up to A=100 nuclide region and the outburst of novae and X-ray bursters. Since many proton resonance levels in odd-A compound nucleus 23Mg may be involved at nova temperature, existing measurements can only provide partial effective information on the 22Na(p, γ)23Mg reaction. Large uncertainties still exist in the astrophysical reaction rates of the two reactions at present. Thick target inverse kinematics method is a very effective way to scan the 23Mg proton resonance levels re#2;lated to the 22Na(p, γ)23Mg reaction via the excitation function of 22Na(p, p) elastic scattering, which could be obtained over a large energy range in one-shot measurement with low-intensity radioactive 22Na beam. In the present work, 22Na+p resonance scattering via thick target inverse kinematics was studied at RIBLL1 radioactive beam line in the HIRFL national laboratory at Lanzhou. A high-purity 22Na beam with an intensity of about 2 × 105 pps was produced via the 1H(22Ne,22Na)n reaction with an alcohol-cooled hydrogen gas target. Time-of-Flight by two plastic scintillator detectors and two parallel-plate avalanche counters were used to monitor the 22Na secondary beam before reaching the (CH2 )n target. The timing information is useful for beam particle identification and the position information is essen#2;tial for 22Na(p,p) elastic scattering kinematics reconstruction. Light recoil particles from 22Na+p reaction system were detected by two sets of double-sided silicon strip detector telescopes centered at 𝜃lab = 0° and 14°, respectively, while the heavy recoil particles were stopped in the (CH2 )n thick target. Two-body kinematics reconstruction of 22Na(p,p) elastic scattering is performed on the event-by-event basis, and an excitation function of 22Na(p,p) is obtained in the energy range of 𝐸c.m. = 1.5 to 4 MeV. Obvious proton resonance structure is observed in the 23Mg compound nucleus, which will be further analyzed with R-matrix nuclear theoretical model.
Subjects: Physics >> Nuclear Physics submitted time 2023-09-04 Cooperative journals: 《核技术》
Abstract： The first radioactive ion beam line, GIRAFFE, has been built at the CIAE HI-13 tandem accelerator in China. A total of eleven types of radioactive ion beam, including 6He, 7Be, and 8Li, have been generated. Several significant reactions in nuclear astrophysics have been indirectly measured via transfer reactions, and research on nuclear structure, relevant to nuclear astrophysics, has been performed using charge exchange reactions and thick-target experimental methods. A series of single nucleon or α cluster transfer reactions have been measured using a Q3D magnetic spectrometer, and the astrophysical S-factors and reaction rates for essential reactions have been obtained. The obtained results serve as a crucial experimental foundation for research involving element abundance and celestial body models.
Subjects: Physics >> Nuclear Physics submitted time 2023-09-04 Cooperative journals: 《核技术》
Abstract： Supernovae are the most gorgeous fireworks that people can observe in the universe. Their explosion can produce a maximum luminosity 10 billion times that of the Sun, helping scientists see farther. Type Ia supernovae can be used as a standard candle to facilitate measurement of the distance between galaxies in the universe. A supernova explosion will also propel a large number of heavy elements into interstellar space, which is a major driving force for the chemical evolution of galaxies. In addition, supernovae are crucial to the origin of elements in the Milky Way, the formation of the structure of the solar system, and the evolution of life on the Earth. The study of supernovae will further enrich our understanding of the universe and help us solve the mysteries of the expansion of the universe, the generation of heavy elements, and the origin of life. At present, scientists predict that the next supernova will explode at any time, and preparations are in progress for observing the coming supernova.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-18 Cooperative journals: 《材料研究学报》
Abstract： Effect of cyclic heat treatment on microstructure and mechanical properties of a Ti-V microalloyed steel was investigated. Therefore, the metallographic microstructure of the steels after heat treatment for each cycle was succesively examined and the relevant grain size was statistically determined; the cyclically heat-treated steels were also examined by means of SEM and TEM in order to reveal the microstructural evolution and the variations of average size and composition of precipitates in the steels with the increasing cycle number; while their tensile strength and toughness were measured. The results show that with the increasing cycle number, the average grain size of the steels decreases continuously. For mechanical properties, Rm has the same regularity due to the increase of mean size of the complex carbide with cycle numbers, while the AKU initially increases and thereafter decreases as a result of the joint influence of the average grain size and the proportion of proeutectoid ferrite.
Subjects: Medicine, Pharmacy >> Preclinical Medicine submitted time 2022-11-24
Abstract：
[Objective] To explore the diagnostic value and prognosis of METTL16 (METTL16) in pan-carcinoma by bioinformatics method.
[Methods] The gene data of each tumor and normal tissue were obtained from several relevant databases, including the Cancer Cell Line Encyclopedia (CCLE), the Cancer Genome Atlas (TCGA) and the Genotype-Tissue Expression Project (GTEx). The expression levels of METTL16 in different cancers were analyzed.Cox regression analysis and Kaplan-Meier analysis were used to evaluate the relationship between METTL16 expression level and tumor prognosis.The Tumor Immune Evaluation Resource (TIMER) was used to assess the association of METTL16 with immune cell infiltration in cancer.Meanwhile, the relationship between the expression level of METTL16 and common immunoregulatory factors, DNA methyltransferase (DNMTs), mismatch repair (MMRs), microsatellite instability (MSI) and tumor mutation load (TMB) was also analyzed.In addition, gene set enrichment analysis (GSEA) was used to identify key pathways in cancer.
[Results] METTL16 was abnormally expressed in a variety of cancers, and survival analysis showed that its expression was associated with clinical outcomes in many cancer patients.The expression level of METTL16 was positively correlated with the expression levels of six types of immunoinfiltrating cells (B cells, CD4 + T cells, CD8 + T cells, dendritic cells, macrophages and neutrophils) in colon cancer (COAD), kidney clear cell carcinoma (KIRC) and liver cancer (LIHC).In addition, METTL16 expression was significantly associated with immune checkpoint gene expression, MMR, DNA methyltransferase levels, TMB, and MSI in multiple cancers.GSEA also revealed that METTL16 is involved in the regulation of tumor and immune-related signaling pathways.
[Conclusion] METTL16 is closely related to tumor prognosis and tumor immunoinfiltration, and plays an important role in the occurrence and development of various tumors.METTL16 may be a promising prognostic biomarker for various tumors and provide new ideas for future tumor immune research and therapeutic strategies.
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