Possibilities for the synthesis of superheavy element Z=121 in fusion reactions

Based on the dinuclear system model,the calculated evaporation residue cross sections matched well with the current experimental results.The synthesis of superheavy elements Z=121 was systematically studied through combinations of stable projectiles with Z=21-30 and targets with half-lives exceeding 50 d.The influence of mass asymmetry and isotopic dependence on the projectile and target nuclei was investigated in detail.The reactions^(254)Es(^(46)Ti,3n)^(297)121 and^(252)Es(^(46)Ti,3n)^(295)121 were found to be experimentally feasible for synthesizing superheavy element Z=121,with maximal evaporation residue cross sections of 6.619 and 4.123 fb at 219.9 and 223.9 MeV,respectively.

Possibility of reaching the predicted center of the“island of stability”via the radioactive beam-induced fusion reactions

Based on the dinuclear system model,the synthesis of the predicted double-magic nuclei^(298)Fl and 304120 was investigated via neutron-rich radioactive beam-induced fusion reactions.The reaction^(58)Ca+^(244)Pu is predicted to be favorable for producing^(298)Fl with a maximal ER cross section of 0.301 pb.Investigations of the entrance channel effect reveal that the^(244)Pu target is more promising for synthesizing^(298)Fl than the neutron-rich targets^(248)Cm and^(249)Bk,because of the influence of the Coulomb barrier.For the synthesis of 304120,the maximal ER cross section of 0.046 fb emerges in the reaction^(58)V+^(249)Bk,indicating the need for further advancements in both experimental facilities and reaction mechanisms.

Prediction of synthesis cross sections of new moscovium isotopes in fusion‑evaporation reactions

In the framework of the dinuclear system model,the synthesis mechanism of the superheavy nuclides with atomic numbers Z=112,114,115 in the reactions of projectiles 40,^(48)Ca bombarding on targets^(238)U,^(242)Pu,and^(243)Am within a wide interval of incident energy has been investigated systematically.Based on the available experimental excitation functions,the dependence of calculated synthesis cross-sections on collision orientations has been studied thoroughly.The total kinetic energy(TKE)of these collisions with fixed collision orientation shows orientation dependence,which can be used to predict the tendency of kinetic energy diffusion.The TKE is dependent on incident energies,as discussed in this paper.We applied the method based on the Coulomb barrier distribution function in our calculations.This allowed us to approximately consider all the collision orientations from tip-tip to side-side.The calculations of excitation functions of^(48)Ca+^(238)U,^(48)Ca+242Pu,and^(48)Ca+^(243)Am are in good agreement with the available experimental data.The isospin effect of projectiles on production cross-sections of moscovium isotopes and the influence of the entrance channel effect on the synthesis cross-sections of superheavy nuclei are also discussed in this paper.The synthesis cross-section of new moscovium isotopes 278−286 Mc was predicted to be as large as hundreds of pb in the fusion-evaporation reactions of^(35,37)Cl+^(248)Cf,^(38,40)Ar+^(247)Bk,^(39,41)K+247 Cm,^(40,42,44,46)Ca+^(243)Am,45 Sc+^(244)Pu,and^(46,48,50)Ti+237Np,51 V+^(238)U at some typical excitation energies.

Effect of tritium reduction in determining energy gain by using R-matrix method direct laser fusion in D-T reaction

The laser fusion criterion is known as the ρR-Criterion, also called high-gain condition. This parameter is temperature dependent and can be calculated by R-matrix method. This method is applied for determining improved fusion cross-section for the reactions T(d,n)4He, 3He(d,p)4He, D(d,p)T, D(d,n)3He. In this paper the time dependent reaction rate equations for fusion reaction T(d,n)4He are solved and by using the obtained results we computed the fu- sion power density, energy gain versus temperature and ρR-parameter. The obtained results show that a suitable com- bination may be a deuterium fraction fD=0.65 and fT=0.35 which would lead 30% reduction in the tritium content of the fuel mixture, and this choice would not change the energy gain value very much. Finally, the obtained energy gain for D-T reaction by using R-matrix is in good agreement with other theories.

Reaction pathway led by silicate structure transformation on decomposition of CaSiO_3 in alkali fusion process using NaOH

The mechanism of decomposition of calcium inosilicate(CaSiO_3) synthesized through chemical deposition method using analytical reagent NaSiO_3·9H_2O and CaCl_2 during the alkali fusion process using NaOH was investigated by Raman spectroscopy in situ,X-ray diffraction and Fourier transform infrared spectrometer(FTIR).The results show that the tetrahedral silica chains within CaSiO_3 are gradually disrupted and transformed into nesosilicate with the isolated SiO_4 tetrahedra at the beginning of the alkali fusion process.The three intermediates including Ca_2SiO_4,Na_2CaSiO_4 and Na_2SiO_3 appear simultaneously in the decomposition of CaSiO_3,while the final products are Ca(OH)_2 and Na_4SiO_4.It can be concluded that there exist two reaction pathways in the alkali fusion process of CaSiO_3:one is ion exchange,the other is in the main form of the framework structure change of silicate.The reaction pathway is led by silicate structure transformation in the alkali fusion process.

Predictions for production of superheavy nuclei with Z=105–112 in hot fusion reactions

Abstract The effects of mass asymmetry on the production of superheavy nuclei(SHN),within the dinuclear system model,are investigated in this study.It is observed that the fusion probability decreases with decreasing mass asymmetry.A total of 192 possible combinations of projectiles from O to Ti and targets with half-lives longer than30 days for producing SHN^(264)Db,^(265)Db,^(267)Sg,^(268)Bh,268Sg,^(269)Bh,^(271)Hs,^(271)Mt,^(272)Hs,^(272)Mt,^(273)Mt,^(274)Ds,275Ds,^(275)Rg,^(276)Ds,^(276)Rg,^(277)Rg,^(278)Cn,^(279)Cn,and^(280)Cn are examined.Further,the optimal combinations and incident energies for synthesizing these nuclei are predicted.Most of the cross sections for production of SHNare larger than 10 pb;therefore,the process can be carried out with the available experimental equipment.

Diagnostic technique for measuring fusion reaction rate for inertial confinement fusion experiments at Shen Guang-III prototype laser facility

A study is conducted using a two-dimensional simulation program （Lared-s） with the goal of developing a technique to evaluate the effect of Rayleigh-Taylor growth in a neutron fusion reaction region. Two peaks of fusion reaction rate are simulated by using a two-dimensional simulation program （Lared-s） and confirmed by the experimental results. A neutron temporal diagnostic （NTD） system is developed with a high temporal resolution of - 30 ps at the Shen Guang-Ⅲ （SG-Ⅲ） prototype laser facility in China, to measure the fusion reaction rate history. With the shape of neutron reaction rate curve and the spherical harmonic function in this paper, the degree of Rayleigh-Taylor growth and the main source of the neutron yield in our experiment can be estimated qualitatively. This technique, including the diagnostic system and the simulation program, may provide important information for obtaining a higher neutron yield in implosion experiments of inertial confinement fusion.

Reaction rates in blanket assemblies of a fusion-fission hybrid reactor

To validate neutronics calculation for the blanket design of fusion-fission hybrid reactor,experiments for measuring reaction rates inside two simulating assemblies are performed.Two benchmark assemblies were developed for the neutronics experiments.A D-T fusion neutron source is placed at the center of the setup.One of them consists of three layers of depleted uranium shells and two layers of polyethylene shells,and these shells are arranged alternatively.The ^(238)U capture reaction rates are measured using depleted uranium foils and an HPGe gamma spectrometer.The fission reaction rates are measured using a fission chamber coated with depleted uranium.The other assembly consists of depleted uranium and LiH shells.The tritium production rates are measured using the lithium glass scintillation detector which is placed in the LiH region of the assembly.The measured reaction rates are compared with the calculated ones predicted using MCNP code,and C/E values are obtained.

Geant4 simulation of 238U(n,f) reaction induced by D-T neutron source

Knowledge of actinides(n,f) fission process induced by neutron is of importance in the field of nuclear power and nuclear engineering,especially for reactor applications.In this work,fission characteristics of^(238)U(n,f) reaction induced by D-T neutron source were simulated with Geant4 code from multiple perspectives,including the fission production yields,total nubar,kinetic energy distribution,fission neutron spectrum and cumulative γ-ray spectrum of the fission products.The simulation results agree well with the experimental nuclear reaction data(EXFOR) and evaluated nuclear data(ENDF).Mainly,this work was to examine the rationality of the parametric nuclear fission model in Geant4 and to direct our future experimental measurements for the cumulative fission yields of ^(238)U(n,f) reaction.

Positive Q-Value Neutron Transfer Mediated Sub-Barrier Fusion Reactions

Positive Q-value neutron transfer mediated sub-barrier fusion reactions are studied with an empirical coupled channels model, which takes into account neutron rearrangement related only to the dynamical matching condition with no free parameters. Fusion cross sections of collision systems ^32S＋^90,94,96Zr are calculated and analyzed. Logarithmic residual enhancement （LRE） is proposed to evaluate the discrepancy between calculated results and experimental data. The experimental data can be described well with this model for the first time as a whole, while the LRE analysis shows that there are still theoretical systematic deviations.

Fusion Reaction Rate Coefficient for Different Beam and Target Scenarios

Fusion power output is proportional not only to the fuel particle number densities participating in reaction but also to the fusion reaction rate coefficient （or reactivity）, which is dependent on reactant velocity distribution functions. They are usuMly assumed to be dual Maxwellian distribution functions with the same temperature for thermal nuclear fusion circumstances. However, if high power neutral beam injection and minority ion species ICRF plasma heating, or multi-pinched plasma beam head-on collision, in a converging region are required and investigated in future large scale fusion reactors, then the fractions of the injected energetic fast ion tail resulting from ionization or charge exchange will be large enough and their contribution to the non-Maxwellian distribution functions is not negligible, hence to the fusion reaction rate coefficient or calculation of fusion power. In such cases, beam-target, and beam-beam reaction enhancement effect contributions should play very important roles. In this paper, several useful formulae to calculate the fusion reaction rate coefticient for different beam and target combination scenarios are derived in detail

Spins of Fission Nuclei in Incomplete Fusion Reactions Induced by Intermediate Energy Heavy Ions

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Study of p-^(11)B Reaction Associated With Clean Fusion Fuel

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Systematic study of anomalous fragment anisotropies in subbarrier complete fusion-fission reactions

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Explanation of Cold Nuclear Fusion and Biotransmutations

Low energy nuclear reactions are possible in condensed matter because of image forces. They result from induced charges at the surface of metals or very polarizable media. The height and width of the Coulomb barrier in free space can thus be reduced. Nuclear fusion requires also the formation of a compound nucleus in one of its excited states, but two deuterons yield an α particle that has 2 excited states. They are respectively accessible at high or low energies. Since the reduction of the Coulomb barrier depends on the local curvature of the interface, cold fusion becomes autocatalytic, but heat production is controllable. Even microbes, plants and animals can produce transmutations. They are also due to image forces. This solves a basic problem in nuclear physics and there are possible applications: facilitated synthesis of superheavy elements and development of a new type of energy sources. They are moderate, but safe.

融合危险度模糊分级的UAV动态避障方法

针对无人机(UAV)在多障碍环境中面对运动障碍的反应式避障问题,为了在反应避障决策时能够朝向周围障碍更远、更少的方向进行避障,提出了一种融合障碍危险度模糊分级的三维速度障碍避障方法。通过三维速度障碍法,给出探测域内各运动障碍的碰撞预测。选取坐标系三轴方向作为相互独立的可用避障加速度方向,在速度及加速度限制下求解三轴方向上避障加速度方向以及数值区间。通过模糊算法,给出了周围其他静止障碍的危险分级方法,提出优化评价函数对计算各方向上的最优加速度,给出优化避障指令。仿真结果表明,针对复杂环境,UAV在反应避障的同时考虑了其他障碍的影响,相比原算法拥有了更高的避障成功率和更少的避障次数。

比较微创与常规椎间孔入路腰椎融合术在腰椎管狭窄症中的治疗效果

目的 观察微创椎间孔入路腰椎融合术与常规椎间孔入路腰椎融合术在腰椎管狭窄症中的治疗效果。方法 我们收集了淮阳楚氏骨科医院2020年3月至2022年3月期间的100例腰椎管狭窄症患者资料。根据随机对照数字表,将这些患者分为观察组(n=50)和对照组(n=50),比较了两组患者在以下手术观察指标方面的差异:手术切口长度、手术持续时间、术中出血量、术中透视次数、术后伤口引流量、术后下地时间和平均住院天数。同时,我们使用视觉模拟评分法(visual analogue scale,VAS)和腰椎Oswestry功能障碍指数(oswestry disability index,ODI)来评估两组患者在术前、术后3个月、6个月和12个月的腰部和腿部疼痛程度以及腰椎功能情况。我们还统计了两组患者术后的并发症情况。结果 察组患者手术切口长度、术中出血量、术后伤口引流量、术后下地时间和平均住院天数均短于对照组患者(P<0.05)。但是观察组患者术中透视次数和手术持续时间均多于对照组患者(P<0.05)。两组患者通过治疗后腰腿VAS评分,ODI评分与治疗前相比明显降低(P<0.05)。其中,观察组患者术后3、6、12个月时腰腿VAS评分,ODI评分均低于对照组患者(P<0.05)。对照组患者与观察组患者术后并发症发生率无统计学拆(P=0.617)。结论 微创经椎间孔入路腰椎融合术作为治疗腰椎管狭窄症的手术方式,具有创口小、恢复周期短的优势能显著提升腰椎的功能性,缓解腰腿部的疼痛,不会增加不良反应的发生。

重组人Ⅱ型肿瘤坏死因子受体—抗体融合蛋白治疗类风湿关节炎的临床效果

目的 观察重组人Ⅱ型肿瘤坏死因子受体—抗体融合蛋白治疗类风湿关节炎的临床效果及对血清相关指标的影响。方法 选取2020年3月—2022年7月龙岩市第二医院血液风湿科收治的类风湿关节炎患者98例,依据随机抽签法分为联合抗风湿组和常规抗风湿组,每组49例。常规抗风湿组采取常规抗风湿治疗,联合抗风湿组在常规抗风湿组基础上使用注射用重组人Ⅱ型肿瘤坏死因子受体—抗体融合蛋白治疗,2组均持续治疗6个月。比较2组患者临床疗效,治疗前后症状改善情况、血清类风湿炎性指标[C反应蛋白(CRP)、红细胞沉降率(ESR)、类风湿因子(RF)、白介素-6(IL-6)],不良反应。结果 联合抗风湿组治疗总有效率为95.92%,高于常规抗风湿组81.63%(χ^(2)=5.018,P=0.025)。治疗6个月后,2组晨僵时间较治疗前缩短,压痛指数评分、疼痛指数评分较治疗前降低,且联合抗风湿组短/低于常规抗风湿组(P均<0.01);2组CRP、RF、IL-6水平较治疗前下降,ESR较治疗前缩小,且联合抗风湿组低/小于常规抗风湿组(P均<0.01)。联合抗风湿组不良反应总发生率为4.08%,低于常规抗风湿组的18.37%(χ^(2)=5.018,P=0.025)。结论 常规抗风湿治疗基础上采用重组人Ⅱ型肿瘤坏死因子受体—抗体融合蛋白治疗类风湿关节炎的疗效显著,利于临床症状、血清指标的改善,降低炎性因子水平及减少不良反应发生,促进病症好转。

矿焦耦合反应中焦炭显微气孔结构的演变

为了研究焦炭在高炉中的溶损行为,选取冶金焦炭与烧结矿、球团矿,进行不同时间的矿焦耦合反应试验,采用显微图像法分析反应后的焦炭气孔结构,探究其演变规律。结果表明:①随着矿焦耦合反应的进行,焦炭小孔溶并形成中大孔,焦炭的溶蚀深度增加,相较于球团矿,烧结矿耦合反应的扩孔作用稍弱;②焦炭与球团矿耦合反应中气孔结构的溶蚀更剧烈,气孔溶并作用更强,焦炭气孔结构演变速度较快;③焦炭与烧结矿的耦合反应中,深度反应层较厚,缩核程度较小,而焦炭在球团矿环境下,气孔壁溶蚀剧烈,深度反应层较薄,缩核程度较大。

Non-thermal laser driven plasma-blocks for proton boron avalanche fusion as direct drive option

Fusion energy from protons reacting with ^(11) B,HB11,is extremely difficult or impossible when using thermal ignition by laser irradiation.This changes radically when using picosecond laser pulses with powers above petawatts dominated by nonlinear force driven ultrahigh ac-celeration of plasma blocks for a non-thermal initiation of igniting solid density HB11 fuel.For a cylindrical trapping of the reaction,laser produced ultrahigh magnetic fields above kiloTesla,have to be combined.The experimentally confirmed highly increased HB11 fusion gains due to avalanche reaction may lead to a scheme of an environmentally clean and economic power reactor.