快中子^64Zn(n，α)^61Ni反应微分截面实验测量

由于64Zn(n,α)61Ni反应的剩余核是稳定的,不能用通常的活化法来测量,致使该反应截面实验数据缺乏。利用双屏栅电离室作为带电粒子探测器,在En=2.54,4.00,5.03,5.50与5.95MeV5个能点,对64Zn(n,α)61Ni反应的微分截面进行了实验测量,并通过微分截面对角度的积分得到了反应截面。实验在北京大学4.5MV静电加速器上进行。2.54MeV的单能中子采用固体氚-钛靶T(p,n)3He反应产生,其余四种能量的准单能中子通过氘气体靶D(d,n)3He反应获得。绝对中子通量采用238U(n,f)反应来确定,实验过程中用BF3长中子计数器进行相对中子通量监测。测量结果与已有的实验与评价数据进行了比较。

Quantum Algorithm of Imperfect KB Self-organization Pt I: Smart Control-Information-Thermodynamic Bounds

The quantum self-organization algorithm model of wise knowledge base design for intelligent fuzzy controllers with required robust level considered.Background of the model is a new model of quantum inference based on quantum genetic algorithm.Quantum genetic algorithm applied on line for the quantum correlation’s type searching between unknown solutions in quantum superposition of imperfect knowledge bases of intelligent controllers designed on soft computing.Disturbance conditions of analytical information-thermodynamic trade-off interrelations between main control quality measures(as new design laws)discussed in Part I.The smart control design with guaranteed achievement of these trade-off interrelations is main goal for quantum self-organization algorithm of imperfect KB.Sophisticated synergetic quantum information effect in Part I(autonomous robot in unpredicted control situations)and II(swarm robots with imperfect KB exchanging between“master-slaves”)introduced:a new robust smart controller on line designed from responses on unpredicted control situations of any imperfect KB applying quantum hidden information extracted from quantum correlation.Within the toolkit of classical intelligent control,the achievement of the similar synergetic information effect is impossible.Benchmarks of intelligent cognitive robotic control applications considered.

On the Solution to the Separated Equation in the 3-Particle Calogero-Moser Problem

We propose the exact solution of the equation in separated variable which appears in the process of constructing solutions to the quantum Calogero-Moser three-particle problem with elliptic two-particle potential . This solution is found for special values of coupling constants . It can be used for solving three-particle Calogero-Moser problem under the appropriate boundary conditions.

Neutron Activation Analyses Used to Study Elemental Accumulation in Some Marine Macrophytes (Mediterranean Sea Coast of Egypt)

The concentrations of Na, Mg, Al, S, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Se Br, Rb, Sr, Zr, Mo, Ag, Sb, I, Cs, Ba, La, Sm, Eu, Tb, Yb, Hf, Ta, W, Au, Th and U in 6 types of marine macrophytes (algae and seagrass): Gelidium pusillum (Stackhouse) Le Jolis, Ulva intestinalis Linnaeus, Amphiroa rigida J.V. Lamouroux, Hypnea sp., Cystoseira sp. and Posidonia oceanica (L.) Delile (seagrass) collected from 3 stations along the Mediterranean Sea coast of Egypt were determined using instrumental neutron activation analysis. The contents of elements in marine macrophytes indicated that they accumulated elements at different levels depending on their type of species (brown, red, green and seagrass) and the ambient water conditions. However, the concentrations of Cr, Co, Ni, Se, Zr, Mo, Ag, Cs, La, Sm, Eu, Yb, Hf, Ta, Au and U were very similar in all samples. In general the levels of classically investigated elements, particularly Mn, Fe, Co, Ni and Zn determined in the macrophytes in the present study are lower or within the wide range of values previously reported for species of these genera sampled along the Egyptian Mediterranean coast.

Design and testing of an internal hot-cathode-type PIG ion source for superconducting cyclotron

The superconducting cyclotron SC200 is intended to generate a 200 MeV, 400 nA proton beam for future particle therapy. The internal hot-cathode-type Penning ionization gauge (PIG) ion source for the SC200 is designed for the generation of hydrogen ions. A brief description of the design of ion source and test bench, which are used in SC200, is given in this paper. The ion source has been verified on the test bench, and the results indicated that the designed ion source meets the expected requirements. The lifetime of the filament exceeded 100 h in the test. In addition, the extraction voltage and the gas flow that influence the extracted ion current intensity have been tested in the experiment.

Molecular Dynamics Simulations of Perovskites: The Effect of Potential Function Representation on Equilibrium Structural Properties

The perovskites with general formula ABX3 have been widely used as for materials with their unique properties (ferroelectric, piezoelectric, dielectric, catalytic and so on). Hybrid organolead halide perovskites are a class of semiconductors with ABX3 (X = Cl, Br, and I) structures consisting of lead cations in 6-fold coordination (B site), surrounded by an octahedron of halide anions (X site, face centered) together with the organic components in 12-fold cub octahedral coordination. These hybrid perovskites have a direct band gap, a large absorption coefficient as well as high charge carrier mobility that represent a very attractive characteristic of cost-effective solar cells. Basically, these crystals are inorganic solids of CaTiO3 type held together by bonds that are either ionic or partially ionic and partially covalent. In spite of the partially covalent character of the Ti-O bond, the system is modeled by a two-body central force interatomic potential (the form of the Vashishta and Rahman interatomic potential), which has been used successfully for many materials with a perovskite structure. In the present work using molecular dynamics (MD) simulation method we investigate the dynamical and structural behavior of CaTiO3 perovskite at normal pressure and temperature conditions. The MD calculations were performed on a system of 16,000 particles (3200Ca + 3200Ti + 96,00O), initially in an orthorhombic-Pbnm structure. The orthorhombic MD box had edges Lx = 53.4 &Aring, Ly = 53.4 &Aring and Lz = 61.12 &Aring, which provided a density matching the experimental value of ρ = 4 g/cm3. Starting with this structure and using proposed interatomic potentials the MD system stabilizes at room temperature in its initial configuration. The aim of the present study to explore the effect of potential function representations on structural equilibrium properties for the perovskite models including hybrid halide ones outlined above. Concerning the perovskite equilibrium state we elucidate the role of potential function modification on the atomic pair correlation and structural re-organization. The details of the interatomic potential representation have to be crucially important for obtaining of correct analysis data in crystallic, liquid and amorphous phases including perovskite systems.

Intelligent Robust Control of Redundant Smart Robotic Arm Pt II: Quantum Computing KB Optimizer Supremacy

This article is a continuation of the work“Intelligent robust control of redundant smart robotic arm Pt I:Soft computing KB optimizer-deep machine learning IT”.In the first part of the paper,we examined control systems with constant coefficients of the conventional PID controller(based on genetic algorithm)and intelligent control systems based on soft computing technologies.For demonstration,MatLab/Simulink models and a test benchmark of the robot manipulator demonstrated.Advantages and limitations of intelligent control systems based on soft computing technology discussed.Intelligent main element of the control system based on soft computing is a fuzzy controller with a knowledge base in it.In the first part of the article,two ways to implement fuzzy controllers showed.First way applyied one controller for all links of the manipulator and showed the best performance.However,such an implementation is not possible in complex control objects,such as a manipulator with seven degrees of freedom(7DOF).The second way use of separated control when an independent fuzzy controller controls each link.The control decomposition due to a slight decrease in the quality of management has greatly simplified the processes of creating and placing knowledge bases.In this Pt II,to eliminate the mismatch of the work of separate independent fuzzy controllers,methods for organizing coordination control based on quantum computing technologies to create robust intelligent control systems for robotic manipulators with 3DOF and 7DOF described.Quantum supremacy of developed end-to-end IT design of robust intelligent control systems demonstrated.

Solving Systems of Transcendental Equations Involving the Heun Functions

The Heun functions have wide application in modern physics and are expected to succeed the hypergeometrical functions in the physical problems of the 21st century. The numerical work with those functions, however, is complicated and requires filling the gaps in the theory of the Heun functions and also, creating new algorithms able to work with them efficiently. We propose a new algorithm for solving a system of two nonlinear transcendental equations with two complex variables based on the Müller algorithm. The new algorithm is particularly useful in systems featuring the Heun functions and for them, the new algorithm gives distinctly better results than Newton’s and Broyden’s methods. As an example for its application in physics, the new algorithm was used to find the quasi-normal modes (QNM) of Schwarzschild black hole described by the Regge-Wheeler equation. The numerical results obtained by our method are compared with the already published QNM frequencies and are found to coincide to a great extent with them. Also discussed are the QNM of the Kerr black hole, described by the Teukolsky Master equation.

Molecular Dynamics Simulations of the DNA-CNT Interaction Process: Hybrid Quantum Chemistry Potential and Classical Trajectory Approach

In this work the quantum chemistry Tersoff potential in combination with classical trajectory calculations was used to investigate the interaction of the DNA molecule with a carbon nanotube (CNT). The so-called hybrid approach—the classical and quantum-chemical modeling, where the force fields and interaction between particles are based on a definite (but not unique) description method, has been outlined in some detail. In such approach the molecules are described as a set of spheres and springs, thereby the spheres imitate classical particles and the spring the interaction force fields provided by quantum chemistry laws. The Tersoff potential in hybrid molecular dynamics (MD) simulations correctly describes the nature of covalent bonding. The aim of the present work was to estimate the dynamical and structural behavior of the DNA-CNT system at ambient temperature conditions. The dynamical configurations were built up for the DNA molecule interacting with the CNT. The analysis of generated МD configurations for the DNA-CNT complex was carried out. For the DNA-CNT system the observations reveal an encapsulation-like behavior of the DNA chain inside the CNT chain. The discussions were made on possible use of the DNA-CNT complex as a candidate material in drug delivery and related systems.

Extending the Truncated Dyson-Schwinger Equation to Finite Temperatures

In view of the properties of mesons in hot strongly interacting matter, the properties of the solutions of the truncated Dyson-Schwinger equation for the quark propagator at finite temperatures within the rainbow-ladder approximation are analysed in some detail. In Euclidean space within the Matsubara imaginary time formalism, the quark propagator is not longer a O(4) symmetric function and possesses a discrete spectrum of the fourth component of the momentum. This makes the treatment of the Dyson-Schwinger and Bethe-Salpeter equations conceptually different from the vacuum and technically much more involved. The question whether the interaction kernel known from vacuum calculations can be applied at finite temperatures remains still open. We find that, at low temperatures, the model interaction with vacuum parameters provides a reasonable description of the quark propagator, while at temperatures higher than a certain critical value Tc the interaction requires stringent modifications. The general properties of the quark propagator at finite temperatures can be inferred from lattice QCD (LQCD) calculations. We argue that, to achieve a reasonable agreement of the model calculations with that from LQCD, the kernel is to be modified in such a way as to screen the infra-red part of the interaction at temperatures larger than Tc . For this, we analyse the solutions of the truncated Dyson-Schwinger equation with existing interaction kernels in a large temperature range with particular attention on high temperatures in order to find hints to an adequate temperature dependence of the interaction kernel to be further implemented in the Bethe-Salpeter equation for mesons. This will allow investigating the possible in medium modifications of the meson properties as well as the conditions of quark deconfinement in hot matter.

SANC Monte Carlo programs for small-angle Bhabha scattering

Luminosity monitoring at e^(+)e^(−)colliders was investigated using SANC Monte Carlo event generator ReneSANCe and integrator MCSANC for simulation of Bhabha scattering at low angles.Results are presented for center-of-mass energies of the Z boson resonance and at 240 GeV for the conditions of typical luminosity detectors.It is shown that bremsstrahlung events with extremely low electron scattering angles are relevant to match the precision tags of future electron-positron colliders.

Interaction of photons with silver and indium nuclei at energies up to 20 MeV

The yields of photonuclear reactions in the 107Ag,113In,and 115In nuclei were measured.Monte Carlo simulations were performed using the Geant4 code,and the results were compared with the experimental values.The isomeric ratios of the yields in the reactions 107Ag(γ,n)106m,gAg and 113In(γ,m)112m,gIn were determined,and the cross sections for the reactions 107Ag(γ,n)106gAg and 107Ag(γ,2n)105Ag at an energy of 20 MeV were calculated based on the experimental data.

Reactions induced by 30 MeV 3He beam on 9Be:cluster transfer reactions

An experiment was conducted for studying the cluster structure of Be induced by He ions at an energy of 30 MeV.As results of the nuclear reaction^(3)He+^(9)Be,the differential cross sections for the exit channels–elastic,inelastic,α+^(8)Be,^(6)He+^(6)Be,^(6)Li+^(6)Li,and^(7)Be+^(5)He–were measured.Elastic and inelastic scattering data were treated within both the optical model and coupled channel method.A new set of optical potentials was considered for the elastic scattering.The deformation parameter was established for the transition 3/2→5/2.Cluster transfer reactions were analyzed via the coupled reaction channel method.The nuclear reactions with the exit channels^(6)He+^(6)Be,^(6)Li+^(6)Li,and^(7)Be+^(5)He were complemented by two-step transfer mechanisms.The contribution of each reaction mechanism were shown and compared with the findings of other authors.

Measurement of yields and angular distributions ofγ-quanta from the interaction of 14.1 MeV neutrons with oxygen,phosphorus,and sulfur

A study of the inelastic scattering of neutrons with an energy of 14.1 MeV on the nuclei of oxygen,phosphorus,and sulfur was performed at the TANGRA facility at JINR(Dubna).The experiment aimed to refine existing data and obtain new data on the yields and angular distributions ofγ-quanta emitted by the studied nuclei due to neutron-induced nuclear reactions using the tagged neutron method.Two types of detector systems were used to registerγ-quanta.Theγ-ray yields were measured using a high-purity germanium(HPGe)detector.The angular distributions ofγ-rays were obtained using a system of 18 scintillation detectors based on bismuth germanite Bi_(4)Ge_(3)O_(12)(BGO)located around the sample.The performed experiments measured the yields of two transitions for the reaction of tagged neutrons with 16O,nine transitions for the reaction with ^(31)P,and nine transitions for the reaction with ^(32)S for the first time.The angular anisotropy of theγ-radiation accompanying the inelastic scattering of neutrons with an energy of 14.1 MeV on ^(31)P nuclei was also measured for the first time.

Toward a description of the centrality dependence of the charge balance function in the HYDJET++model

Data from the Large Hadron Collider on the charge balance function in Pb+Pb collisions at center-of-mass energy 2.76 TeV per nucleon pair are analyzed and interpreted within the framework of the HYDJET++model.This model allows us to qualitatively reproduce the experimentally observed centrality dependence of the balance function widths at relatively low transverse momentum intervals due to the different charge creation mechanisms in soft and hard processes.However,a fully adequate description of the balance function in these intervals implies an essential modification of the model by including exact charge conservation via the canonical rather than the grand canonical ensemble.A procedure is proposed for introducing charge correlations into the thermal model without changing other model parameters.With increasing transverse momenta,the default model results describe the exper-imental data much better because the contribution of the soft component of the model is significantly reduced in these transverse momentum intervals.In practical terms,there is a transition to a single source of charge correlations,namely,charge correlations in jets in which exact charge conservation holds at each stage.

核对称轴不同相对取向对熔合动力学的影响

计算了核对称轴不同相对取向时的熔合位垒.基于双核模型观念,考虑了熔合与准裂变的竞争,通过数值法求解主方程,计算了76Ge+208Pb,48Ca+244Pu核对称轴不同相对取向对熔合概率的影响,探索了最有利于超重元素合成的弹靶相对取向.取向不同时,对熔合反应的影响较大,计算结果表明弹靶碰撞为腰对腰时,更有利于发生熔合反应.

合成和研究稀土区质子滴线附近的6种新核素

利用兰州重离子加速装置（HIRFL）的SFC加速器引出的能量为165—180MeV的36Ar重离子束，分别轰击92Mo、96Ru和106Cd缺中子同位位素靶，产生了稀土区质子滴线附近的新核素125Nd、128Pm、129Sm、137Gd1）、139Dy和139Tb.借助高灵敏度的氦喷嘴快速带传输系统和“p-γ”或“X-γ”符合测量方法对它们进行了分离鉴别，确定它们的半衰期分别为（0．60±0．15）s，（1．0±0．3）s，（0．55±0．10）s，（2．2±0．2）s，（0．6±0．2）s和（1．6±0．2）s，并测量了125Nd、128Pm、129Sm、137Gd和139Dy的β延发质子能谱，指认了能量为109．0和119．7keV的两条γ射线属于139Tb的EC／β＋衰变．