Optimized transfer trajectories in the earth-moon system

Investigations of low energy transfer trajectories are important for both celestial mechanics and astronautics. Methodologies using the theories from dynamical systems are developed in recent years. This paper investigates the dynamics of the earth-moon system. Low energy transfer trajectories are solved numerically by employing a hybrid strategy： first, a genetic hide and seek method performs a search in large domain to confine the global minimum f（η） （objective function） region; then, a deterministic Nelder-Mead method is utilized to refine the minimum quickly. Some transfer trajectories of the spacecraft in the earth-moon system are successfully simulated which verify the desired efficiency and robustness of the method of this paper.     

On the microparticle charge in the Earth’s ionosphere

The model problem of submicrometer particle charging under solar radiation at an altitude of ～90 km is considered. Within the constructed model, the dependence of the particle charge on the bulk density of particles, their size, and ionization probability due to the photoelectric effect is calculated. The features of the electron energy distribution function are also analyzed.     

On the metal–insulator transition in vanadium dioxide

The conductivity σ of vanadium dioxide (VO₂) drops at a metal–insulator transition by four orders of magnitude due to the structural change between tetragonal and monoclinic crystals. In order to elucidate this conductivity drop, we introduce the semiclassical equation of motion to describe the dynamics of the conduction electron (wave packet), where the existence of a k-vector k is prerequisite for the conduction. We showed that the periodicity using the non-orthogonal bases does not legitimize the electron dynamics in solids. The theory suggests that the decrease in the dimensionality of the k-vectors due to the structural change is the cause of the conductivity drop.     

Effect of doping germanium oxide with metal ions on optical charge “memory” in Ge-GeO2 system

The paper presents the results of experiments aimed at ascertaining the possibility of controlling the photomemory in the Ge-GeO₂ system by the technique of doping the oxide layer with metal ions. It is shown that under certain conditions doping of such a system with Na, K, Cs, Cr, and Ti ions results in the formation of deep electron traps which are recharged under illumination. A study was made of how heating in a vacuum and in oxygen as well as adsorption of water and ammonia affect the optical charging and the density of fast surface states for doped specimens.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 105–109, October, 1978.In conclusion, the authors thank V. F. Kiselev for his constant interest in the work and his valuable comments.     

Evidence for a double charge transfer contribution to SERS in the Ag/Ag (CN)2− system

Using a square wave potential perturbation and monitoring the Raman intensity in parallel, the potential dependence of Ag(CN)₂⁻ spectra was studied with different exciting wavelengths. A double peak structure was found for the C-N stretch frequency both peaks having different excitation characteristics. In addition, the quenching rate of ad-complexes was measured at negative potentials together with the activation energy. From E_A = 75 kJ mol⁻, the energy of an acceptor level can be estimated located about 3 eV above E_F. This level presumably corresponds to the Ag 5s orbital which is shifted upwards due to the interaction with the ligands of the ad-complex. Since the CN⁻ 5σ or 1π orbitals form a donor level, the possibility of a double charge transfer contribution to the SERS enhancement exists.     

Reaction-diffusion processes in the “adsorbate-substrate” system

We obtain a chain of quantum kinetic reaction-diffusion-type equations for “adsorbate-substrate” system taking into account the coupling of a light particle with a metallic surface, the adsorbate surface diffusion by the tunnelling mechanism and the occurrence of bimolecular chemical reactions. We calculate the temperature dependence of the kinetic kernels related to the diffusion coefficients and the reaction rates. It is shown that one can alter the temperature dependence of the reaction rates by changing the “adsorbate-substrate” coupling. It is also shown that the mean field terms contribute to the activation energies of the reaction rates, while their contribution to the activation energies of the diffusion coefficients vanishes.     

Cage-like structure and charge hollow in the immiscible Cu–Ta system

Ground states of the immiscible Cu–Ta system are investigated by a hybrid approach of first-principles calculation and cluster expansion method. The obtained pairs, triplets, and tetrads cluster interactions show that the closer-packed cluster may not always contribute to stabilize structures. A CuTa₇ phase with a cage-like structure is predicted to be stable at ground state. The obtained spatial valence charge density shows that there exists a charge hollow within this cage-like structure, contributing to stabilize CuTa₇ phase.     

On the behaviour of artificial head transfer system applied to acoustic evaluation researches for halls

The author has made tests for an artificial head transfer system whichis modelled on a Chinese male on its main physical behaviour such as frequencyresponses,frequency response differences between the front and the rear inci-dences,as will as on its important hearing behaviour such as localization,theperception of distance and room dimensions.The results verify that this kind ofartificial head transfer system can be used as one of effective tools of acousticevaluation researches for halls.     

On the possible role of small polarons in the charge and energy transport in the α-helix proteins

We study the possibility of the small-polaron creation in α-helix proteins, accounting for the self-trapping of the intramolecular vibration energy quanta. The small-polaron concept of energy transfer in polypeptides has been revisited on the basis of these results. It was found that traditional small-polaron theories cannot be directly applied to the vibrational quanta transfer in these substances. In particular, true eigenstates of system should correspond to a partial dressed polarons rather than to the fully dressed small polaron states.     

Mössbauer studies of the charge transfer process in the system (Li0.5Fe0.5)1−xFexFe2O4

Conclusion The formation of heterovalent pairs seems to be proved for the compounds rich in Fe²⁺ ions (x0.5) and the electron-phonon coupling seems to change with decreasing concentration of Fe²⁺ ions.Nevertheless the pairs model is not necessarily an unique interpretation of the data for x0.5 /1/ and the broadening of the Fe^m+ ions spectrum could be worked considering electronic and atomic disorders.     

On the theory of electronic states of the “epitaxial graphene-quantum-well film” system

The problem of an epitaxial graphene formed on a thin metal film in an external magnetic field has been considered. It has been shown that the problem can be solved using the Green’s function method within the Kadanoff-Baym formalism. Analytical expressions for the transferred charge as a function of the magnetic field and the thickness of the film have been obtained.     

“Superslow” processes in the Ge-GeO2 system

A study was made of the charged state on a natural or an oxidized germanium surface during heat-and-field treatment. This study dealt with the kinetics of charging and discharging of superslow surface states. The thermal activation energy of these charging and discharging processes has also been evaluated. Conclusions are drawn about the possible nature of superslow traps in the Ge-GeO₂ system.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No.2, pp.79–86, February, 1976.In conclusion, the authors thank V. F. Kiselev for the useful discussion of this report and his valuable comments.     

Dark-state mechanism for the long-time transfer of excitations in a donor–acceptor system

The excitation energy transfer between a donor–acceptor pair with fixed distance apart through energy exchanging with environment is investigated. The total system is modeled as two two-level systems (TLSs) interacting with many harmonic oscillators. The pair behaves coherently or incoherently, depending on whether the dipolar coupling is stronger or weaker than the TLS–environment coupling. The environmental linear dispersion relation gives an analytical solution to the pair?s probability involving all the retardation times. We found that the long-time trapping of energy within the pair is caused by the inhibiting dark-state radiative decay when two TLSs are at half a resonant wavelength.     

On the interaction of the Dirac oscillator with the Aharonov–Casher system in topological defect backgrounds

In this paper, we study the influence of the Aharonov–Casher effect [Y. Aharonov, A. Casher, Phys. Rev. Lett. 53 (1984) 319] on the Dirac oscillator in three different scenarios of general relativity: the Minkowski spacetime, the cosmic string spacetime and the cosmic dislocation spacetime. In this way, we solve the Dirac equation and obtain the energy levels for bound states and the Dirac spinors for positive-energy solutions. We show that the relativistic energy levels depend on the Aharonov–Casher geometric phase. We also discuss the influence of curvature and torsion on the relativistic energy levels and the Dirac spinors due to the topology of the cosmic string and cosmic dislocation spacetimes.     

On the “projective” magnetohydrodynamics

In the projective relativity based on the de Sitter universe, Maxwell's generalized theory gives us the magnetohydrodynamics, valid on a cosmic scale, for hyperdense matter and high energies. From the new theory can be deduced as limiting cases the hydrodynamics and thermohydrodynamics, the ideal magnetohydrodynamics, the electromagnetism, and the electrohydrodynamics, invariants for the projective Fantappié group.     

On the Sharp Constant in the “Magnetic” 1D Embedding Theorem

The problem of finding the sharp (exact) constant in the “magnetic” embedding theorem is considered.     

On the microstructure of the charge density wave observed in La1− x Ca x MnO3

We have used low temperature (90?K) transmission electron microscopy to investigate the ‘charge ordering’ modulation in the mixed valent manganite, La_{1? x} Ca _x MnO₃. It has been stated that Mn³⁺ and Mn⁴⁺ ions order at low temperature to produce a structural modulation composed of supercells whose size is an integer multiple of the unmodulated unit cell. Here, we use convergent beam electron diffraction to show that the periodicity of the modulation need not be an integer multiple of the undistorted cell, even on the smallest scales. We therefore suggest that this modulation is a charge density wave with a uniform periodicity. We show that the modulation wavevector lies close to the a* axis of the crystal but need not be exactly collinear. A typical grain of size 0.5?µm in La_0.48Ca_0.52MnO₃ had a wavevector which varied on a scale of tens of nanometres with an average of ?q??=?0.450a * and a standard deviation Δq?=?0.004?a* in its magnitude and Δθ?=?0.56° in its direction at 90?K. The magnitude of the wavevector in this composition fell by 20% as the temperature was increased from 90?K to room temperature. This change occurred by nucleation and growth. Although weak, the modulation was still present at room temperature, some 30?K above the ‘charge ordering temperature’.     

Improved laser-induced forward transfer of organic semiconductor thin films by reducing the environmental pressure and controlling the substrate–substrate gap width

Laser-induced forward transfer (LIFT) has been investigated for bilayer transfer material systems: silver/organic film (Alq₃ or PFO). The LIFT process uses an intermediate dynamic release layer of a triazene polymer. This study focuses on the effect of introducing a controlled donor–receiver substrate gap distance and the effect of doing the transfer at reduced air pressures, whilst varying the fluence up to ∼200 mJ/cm². The gap between ‘in-contact’ substrates has been measured to be a minimum of 2–3 μm. A linear variation in the gap width from ‘in contact’ to 40 μm has been achieved by adding a spacer at one side of the substrate–substrate sandwich. At atmospheric pressure, very little transfer is achieved for Alq₃, although PFO shows some signs of successful doughnut transfer (with a large hole in the middle) in a narrow fluence range, at gaps greater than 20 μm. For the transfer of Ag/PFO bilayers at atmospheric pressure, the addition of a PFO layer onto the receiver substrate improved the transfer enormously at smaller gaps and higher fluences. However, the best transfer results were obtained at reduced pressures where a 100% transfer success rate is obtained within a certain fluence window. The quality of the pixel morphology at less than 100 mbar is much higher than at atmospheric pressure, particularly when the gap width is less than 20 μm. These results show the promise of LIFT for industrial deposition processes where a gap between the substrates will improve the throughput.