One-step green method to prepare progressive burning gun propellant through gradient denitration strategy

Gradiently denitrated gun propellant(GDGP)prepared by a“gradient denitration”strategy is obviously superior in progressive burning performance to the traditional deterred gun propellant.Currently,the preparation of GDGP employed a tedious two-step method involving organic solvents,which hinders the large-scale preparation of GDGP.In this paper,GDGP was successfully prepared via a novelty and environmentally friendly one-step method.The obtained samples were characterized by FT-IR,Raman,SEM and XPS.The results showed that the content of nitrate groups gradiently increased from the surface to the core in the surface layer of GDGP and the surface layer of GDGP exhibited a higher compaction than that of raw gun propellant,with a well-preserved nitrocellulose structure.The denitration process enabled the propellant surface with regressive energy density and good progressive burning performance,as confirmed by oxygen bomb and closed bomb test.At the same time,the effects of different solvents on the component loss of propellant were compared.The result showed that water caused the least component loss.Finally,the stability of GDGP was confirmed by methyl-violet test.This work not only provided environmentally friendly,simple and economic preparation of GDGP,but also confirmed the stability of GDGP prepared by this method.

Continuum Skyrme Hartree-Fock-Bogoliubov theory with Green’s function method for neutron-rich Ca,Ni,Zr,and Sn isotopes

The possible exotic nuclear properties in the neutron-rich Ca,Ni,Zr,and Sn isotopes are examined with the continuum Skyrme Hartree-Fock-Bogoliubov theory in the framework of the Green’s function method.The pairing correlation,the couplings with the continuum,and the blocking effects for the unpaired nucleon in odd-A nuclei are properly treated.The Skyrme interaction SLy4 is adopted for the ph channel and the density-dependentinteraction is adopted for the pp chan-nel,which well reproduce the experimental two-neutron separation energies S_(2n)and one-neutron separation energies Sn.It is found that the criterion S_(n)>0 predicts a neutron drip line with neutron numbers much smaller than those for S_(2n)>0.Owing to the unpaired odd neutron,the neutron pairing energies−E_(pair)in odd-A nuclei are much lower than those in the neighbor-ing even-even nuclei.By investigating the single-particle structures,the possible halo structures in the neutron-rich Ca,Ni,and Sn isotopes are predicted,where sharp increases in the root-mean-square(rms)radii with significant deviations from the traditional rA^(1∕3)rule and diffuse spatial density distributions are observed.Analyzing the contributions of various partial waves to the total neutron densityρlj(r)∕ρ(r)reveals that the orbitals located around the Fermi surface-particularly those with small angular momenta-significantly affect the extended nuclear density and large rms radii.The number of neutrons Nλ(N_(0))occupying above the Fermi surfacen(continuum threshold)is discussed,whose evolution as a function of the mass number A in each isotope is consistent with that of the pairing energy,supporting the key role of the pairing correlation in halo phenomena.

A simplified two-dimensional boundary element method with arbitrary uniform mean flow

To reduce computational costs, an improved form of the frequency domain boundary element method（BEM） is proposed for two-dimensional radiation and propagation acoustic problems in a subsonic uniform flow with arbitrary orientation. The boundary integral equation（BIE） representation solves the two-dimensional convected Helmholtz equation（CHE） and its fundamental solution, which must satisfy a new Sommerfeld radiation condition（SRC） in the physical space. In order to facilitate conventional formulations, the variables of the advanced form are expressed only in terms of the acoustic pressure as well as its normal and tangential derivatives, and their multiplication operators are based on the convected Green＇s kernel and its modified derivative. The proposed approach significantly reduces the CPU times of classical computational codes for modeling acoustic domains with arbitrary mean flow. It is validated by a comparison with the analytical solutions for the sound radiation problems of monopole,dipole and quadrupole sources in the presence of a subsonic uniform flow with arbitrary orientation.

Two New Identification Methods for Encephalitozoon cuniculi on Tissue Section

[ Objective] The paper aimed to search new identification methods of Encephalitozoon cuniculi on tissue sections. [ Method] Using improved Gram staining method and methyl green pyronin staining method, the pathological sections of sick rabbits were stained and identified. [ Result] The pathological changes in brain tissue could be clearly observed on sections, but parasites were not examined in pathological brain tissues stained by common staining method. When the pathological section was stained by improved Gram staining method, the pathological changes in brain tissue were not ouly stained very clearly, but blue parasites were also found in brain tissues. The parasites in epithelioid cells were stained into purple ones by methyl green pyronin staining method. [ Conclusion] The im- proved Gram staining method and methyl green pyronin staining method performed good staining effects of E. cuniculi in pathological sections, which were conducive to rapid diagnosis of encephalitozoonosis in rabbit.

Numerical analysis of added mass and damping of floating production,storage and offloading system

An integral equation approach is utilized to in- vestigate the added mass and damping of floating produc- tion, storage and offloading system （FPSO system）. Finite water depth Green function and higher-order boundary ele- ment method are used to solve integral equation. Numeri- cal results about added mass and damping are presented for odd and even mode motions of FPSO. The results show ro- bust convergence in high frequency range and can be used in wave load analysis for FPSO designing and operation.

Theoretical Investigation of Exchange Bias in Compensated Cases

The exchange bias （EB） of the ferromagnetic （FM）/antiferromagnetic （AFM） bilayers in a compensated case is studied by use of the many-body Green＇s function method of quantum statistical theory. The so-called compensated case is that there is no net magnetization on the AFM side of the interface. Our conclusion is that the EB in this case is primarily from the asymmetry of the interracial exchange coupling strengths between the FM and the two sublattices of the AFM. The effects of the layer thickness, temperature and the interracial coupling strength oi2 the exchange bias HE are investigated. The dependence of HE on the FM layer thickness and temperature is qualitatively in agreement with experimental results. HE is nearly inversely proportional to FM thickness. When temperature varies, both HE and He decrease with temperature increasing. The anisotropy of the FM layer only slightly influence He, but does not influence HE.

Statistical Average of Spin Operators for Calculation of Three-Component Magnetization （II）： Solution of Equation

In this paper, the solution of Chebyshev equation with its argument being greater than 1 is obtained. The initial value of the derivative of the solution is the expression of magnetization, which is valid for any spin quantum number S. The Chebyshev equation is transformed from an ordinary differential equation obtained when we dealt with Heisenberg model, in order to calculate all three components of magnetization, by many-body Green＇s function under random phase approximation. The Chebyshev functions with argument being greater than 1 are discussed. This paper shows that the Chebyshev polynomials with their argument being greater than 1 have their physical application.

Simulation of strong earthquake characteristics of a scenario earthquake(M_(S)7.5)based on the enlightenment of 2022 M_(S)6.9 earthquake in Menyuan

The Menyuan area is an important transportation hub in the Hexi Corridor.The Menyuan M_(S)6.9 earthquake that occurred on January 8,2022 had a major impact on the local infrastructure and transportation of this region.Due to the high possibility of similar strong earthquakes occurring in this area in the future,preliminary assessment of the seismic intensity characteristics of destructive earthquakes in this region is essential for effective disaster control.This paper uses the empirical Green′s function(EGF)method as a numerical simulation tool to predict the ground motion intensity of Datong Autonomous County under the action of the scenario earthquake(M_(S)7.5).Seismic records of aftershocks of the 2016 Menyuan M_(S)6.4 earthquake were used as Green’s functions for this simulation.The uncertainties associated with various source parameters were considered,and 36possible earthquake scenarios were simulated to obtain 72 sets of horizontal ground motions in Datong County.The obtained peak ground acceleration(PGA)vs.time histories of the horizontal ground motion were screened using the attenuation relationships provided by the fifth-edition of China’s Seismic Ground Motion Parameter Zoning Map and the NGA-West2dataset.Ultimately,32 possible acceleration-time histories were selected for further analysis.The screened PGA values ranged from 78.8 to 153 cm/s^(2).The uncertainty associated with the initial rupture point was found to greatly affect the results of the earthquake simulation.The average acceleration spectrum of the selected acceleration-time history exceeded the expected spectrum of a intermediate earthquake,which means that buildings in Datong County might sustain some damage should the scenario earthquake occur.This research can provide reliable ground motion input for urban earthquake damage simulation and seismic design in Datong County.Growing the dataset of small earthquakes recorded in this region will facilitate the large-scale simulation of ground motions under different earthquake scenarios.

MAGNETOHYDRODYNAMIC PIPE FLOW IN DUCTS WITH PARTIAL CIRCULAR RING CROSS SECTION AND ANNULAR CROSS SECTION

In this paper we use the Green function method to solve the problem of steady one dimensional flow of an incompressible viscous, electrically conducting fluid through a pipe with partial circular ring cross sec- tion and one with annular cross section, in the presence of an applied transverse uniform magnetic field, We ob- tain analytic solutions and carry out some numerical calculations of the velocity distribution and induced magnet- ic field.

Thermodynamic properties of Heisenberg magnetic systems

In this paper, we present a comprehensive investigation of the effects of the transverse correlation function （TCF） on the thermodynamic properties of Heisenberg antiferromagnetic （AFM） and ferromagnetic （FM） systems with cubic lattices. The TCF of an FM system is positive and increases with temperature, while that of an AFM system is negative and decreases with temperature. The TCF lowers internal energy, entropy and specific heat. It always raises the free energy of an FM system but raises that of an AFM system only above a specific temperature when the spin quantum number is S 〉 1. Comparisons between the effects of the TCFs on the FM and AFM systems are made where possible.

Polarization resolved analysis of phonon transport in a multi-terminal system

The atomistic Green’s function method is improved to compute the polarization resolved phonon transport in a multiterminal system. Based on the recent developments in literature, the algorithm is simplified. The complex phonon band structure of a semi-infinite periodic terminal is obtained by the generalized eigenvalue equation. Then both the surface Green’s function and phonon group velocity in the terminal are determined from the wave modes propagating away from the scattering region along the terminal. With these key ingredients, the individual phonon mode transmittance between the terminals can be calculated. The feasibility and validity of the method are demonstrated by the chain example compared with the wave packet method, and an example of graphene nanojunction with three terminals.

Magnetic Properties of One-Dimensional Ferromagnetic Mixed-Spin Model within Tyablikov Decoupling Approximation

In this paper, we apply the two-time Green's function method, and provide a simple way to study themagnetic properties of one-dimensional spin-(S, s) Heisenberg ferromagnets.The magnetic susceptibility and correlationfunctions are obtained by using the Tyablikov decoupling approximation.Our results show that the magnetic susceptibilityand correlation length are a monotonically decreasing function of temperature regardless of the mixed spins.It isfound that in the case of S = s, our results of one-dimensional mixed-spin model is reduced to be those of the isotropicferromagnetic Heisenberg chain in the whole temperature region.Our results for the susceptibility are in agreement withthose obtained by other theoretical approaches.

Quantum transport through a Z-shaped silicene nanoribbon

In this work,the electronic transport properties of Z-shaped silicene nanoribbon（ZsSiNR） structure are investigated.The calculations are based on the tight-binding model and Green＇s function method in Landauer-Biittiker formalism,in which the electronic density of states（DOS）,transmission probability,and current-voltage characteristics of the system are calculated,numerically.It is shown that the geometry of the ZsSiNR structure can play an important role to control the electron transport through the system.It is observed that the intensity of electron localization at the edges of the ZsSiNR decreases with the increase of the spin-orbit interaction（SOI） strength.Also,the semiconductor to metallic transition occurs by increasing the SOI strength.The present theoretical results may be useful to design silicene-based devices in nanoelectronics.

Theoretical design of single-molecule NOR and XNOR logic gates by using transition metal dibenzotetraaza[14]annulenes

The idea of replacing traditional silicon-based electronic components with the ones assembled by organic molecules to further scale down the electric circuits has been attracting extensive research focuses.Among the molecularly assembled components,the design of molecular logic gates with simple structure and high Boolean computing speed remains a great challenge.Here,by using the state-of-the-art nonequilibrium Green’s function theory in conjugation with first-principles method,the spin transport properties of single-molecule junctions comprised of two serially connected transition metal dibenzotetraaza[14]annulenes(TM(DBTAA),TM=Fe,Co)sandwiched between two single-walled carbon nanotube electrodes are theoretically investigated.The numerical results show a close dependence of the spin-resolved current-voltage characteristics on spin configurations between the left and right molecular kernels and the kind of TM atom in TM(DBTAA)molecule.By taking advantage of spin degree of freedom of electrons,NOR or XNOR Boolean logic gates can be realized in Fe(DBTAA)and Co(DBTAA)junctions depending on the definitions of input and output signals.This work proposes a new kind of molecular logic gates and hence is helpful for further miniaturization of the electric circuits.

Three-Terminal Transport of Nonsymmetric T-Shaped Graphene Nanoribbons

In order to explore the transport properties of nonsymmetric three-terminal T-shaped graphene nanoribbons (GNRs) devices,the nonequilibrium Green's function method and Landauer-Buttiker formula were adopted. It shows that the transport properties of T-shaped GNRs are highly sensitive to the details of the leads. The T-shaped GNRs show metallic characteristics when electrons transmit from the metallic GNRs lead to the metallic GNRs lead, while the T-shaped GNRs show semiconducting characteristics when electrons transmit from the metallic GNRs lead to the semiconducting GNRs lead. The conductance between the random two leads can be adjusted by varying the size of the leads.

Improvement of the thermoelectric efficiency of pyrene-based molecular junction with doping engineering

In this study, the thermoelectric properties of pyrene molecule doped with boron and nitrogen atom at different sites of molecule are investigated using density functional theory and none-equilibrium Greens function formalism in the linear response regime. Our calculations show that when the impurities are added to the edge of the molecule, the anti-resonant peaks will appear in the transmission diagram in the vicinity of the Fermi energy level. So it increases the thermoelectric figure of merit of the system in comparison with the one that the impurity is located in the center of molecule. Additionally, the seebeck coefficient signs are not the same among the B, N, and N ＆ B doped devices, indicating that the types of the carriers can be changed with different types of doping.

A green method to synthesize flowerlike Fe(OH)3 microspheres for enhanced adsorption performance toward organic and heavy metal pollutants

Dyestuffs and heavy metal ions in water are seriously harmful to the ecological environment and human health. Three-dimensional （3D） flowerlike Fe（OH）3 microspheres were synthesized through a green yet low-cost injection method, for the removal of organic dyes and heavy metal ions. The Fe（OH）3 microspheres were characterized by thermal gravimetric analysis （TGA）, Fourier transform infrared （FT-IR}, and transmission electron microscopy （TEM） techniques. The adsorption kinetics of Congo Red （CR） on Fe（OH）3 microspheres obeyed the pseudo-second-order model. Cr6＋ and Pb2＋ adsorption behaviors on Fe（OH）3 microspheres followed the Langmuir isotherm model. The maximum adsorption capacities of the synthesized Fe（OH）3 were 308, 52.94, and 75.64 mg/g for CR, Cr6＋, and Pb2＋ respectively. The enhanced adsorption performance originated from its surface properties and large specific surface area of 250 m2/g. The microspheres also have excellent adsorption stability and recyclability. Another merit of the Fe（OH）3 material is that it also acts as a Fenton-like catalyst. These twin functionalities （both as adsorbent and Fenton-like catalyst） give the synthesized Fe（OH）3 microspheres great potential in the field of water treatment.

BEM for wave interaction with structures and low storage accelerated methods for large scale computation

The boundary element method（BEM） is a main method for analyzing the interactions between the waves and the marine structures. As with the BEM, a set of linear equations are generated with a full matrix, the required calculations and storage increase rapidly with the increase of the structure scale. Thus, an accelerated method with a low storage is desirable for the wave interaction with a very large structure. A systematic review is given in this paper for the BEM for solving the problem of the wave interaction with a large scale structure. Various integral equations are derived based on different Green functions, the advantages and disadvantages of different discretization schemes of the integral equations by the constant panels, the higher order elements, and the spline functions are discussed. For the higher order element discretization method, the special concerns are given to the numerical calculations of the single-layer potential, the double layer potential and the solid angle coefficients. For a large scale computation problem such as the wave interaction with a very large structure or a large number of bodies, the BEMs with the FMM and p FFT accelerations are discussed, respectively, including the principles of the FMM and the p FFT, and their implementations in various integral equations with different Green functions. Finally, some potential applications of the acceleration methods for problems with large scale computations in the ocean and coastal engineering are introduced.

Resonances with triaxial deformation in the complex scaled Green's function method

We extend the complex scaled Green＇s function （CGF） method to describe resonances with triaxial deformation and present a theoretical formalism. Taking 43S as an example, we elaborate numerical details and demonstrate how to determine the resonance parameters. With changes in the deformation parameters, we study the influence of the triaxial deformation parameter γ on single-particle levels. In particular, the present scheme focuses on the advantages of the complex scaling method （CSM） and the Green＇s function method, and is suitable for the exploration of resonances.

ANALYTICAL SOLUTION OF GROUNDWATER FLUCTUATIONS IN ESTUARINE AQUIFER

As a basic factor in the environment of estuary, tidal effects in the coastal aquifer have recently attracted much attention because tidal dynamic also greatly influences the solute transport in the coastal aquifer. Previous studies on tidal dynamic of coastal aquifers have focused on the inland propagation of oceanic tides in the cross-shore direction, a configuration that is essentially one-dimensional. Two-dimensional analytical solutions for groundwater level fluctuation in recent papers are localized in presenting the effect of both oceanic tides and estuarine tides in quadrantal aquifer. A two-dimensional model of groundwater fluctuations in estuarine zone in proposed in this paper. Using complex transform, the two-dimensional flow equation subject to periodic boundary condition is changed into time-independent elliptic problem. Based on Green function method, an analytical solution for groundwater fluctuations in fan-shaped aquifer is derived. The response to of groundwater tidal loading in an estuary and ocean is discussed. The result show that its more extensive application than recent studies.