Evidence for charged critical behavior in the pyrochlore superconductor RbOs2O6

We analyze magnetic penetration depth (lambda) data of the recently discovered superconducting pyrochlore oxide RbOs(2)O(6). Our results strongly suggest that in RbOs(2)O(6) charged critical fluctuations dominate the temperature dependence of lambda near T(c). This is in contrast with the mean-field behavior observed in conventional superconductors and the uncharged critical behavior found in nearly optimally doped cuprate superconductors. However, this finding agrees with the theoretical predictions for charged criticality and the charged criticality observed in underdoped YBa(2)Cu(3)O(6.59).     

Evidence for core-shell magnetic behavior in antiferromagnetic Co3O4 nanowires

Employing magnetometry measurements, we have studied Co3O4 nanowires focusing on the core-shell behavior. We find two magnetic contributions, i.e., a regular antiferromagnetic and an additional irreversible one. The first contribution can be attributed to the antiferromagnetically ordered wire cores. The nature of the second one can be identified using thermoremanent and isothermoremanent magnetizaton curves as magnetic fingerprints of the irreversible magnetization. We conclude that the nanowire shell behaves like a two-dimensional diluted antiferromagnet in a field.     

Evidence for an energy scale for quasiparticle dispersion in Bi2Sr2CaCu2O8

Quasiparticle dispersion in Bi2Sr2CaCu2O8 is investigated with improved angular resolution as a function of temperature and doping. Unlike the linear dispersion predicted by the band calculation, the data show a sharp break in dispersion at 50+/-15 meV binding energy where the velocity changes by a factor of 2 or more. This change provides an energy scale in the quasiparticle self-energy. This break in dispersion is evident at and away from the d-wave node line, but the magnitude of the dispersion change decreases with temperature and with increasing doping.     

Study on micro-mirror macro model and its dynamic behavior

Research on modeling electrostatic micro actuator is essential for the effective control of its action. In this paper, a kind of modeling way is presented for conventional tilting reflecting micro mirror. A polynomial algebraic equation for angel of a tilting 2 orders torque system is introduced and the characters of the model are estimated precisely. Simulation and experiment are implemented for proving the method. Finally, PID control algorithm is exerted hence based on the model and the dynamic response feature is promoted.     

Analternative model for the conductivity behavior of K2Pt(CN)4Br0.3·3H2O

It is shown that the reordering of the bromine atoms into a new cubic lattice at low temperatures can produce the changes observed in the conductivity behavior of the mixed valence salt K₂Pt(CN)₄Br_0.32·3H₂O. The optical data are examined in terms of an RPA calculation of the dielectric response of the crystal and it is noted that a periodic potential can reproduce the observed structure in the imaginary part without the need for identifying the charge carriers.     

Anomalous critical behavior of NaV2O5

The temperature dependences and critical behavior of the dielectric constant were studied in NaV₂O₅ along the c axis in a frequency range of 1 MHz-1GHz and a temperature range of 4.2–300 K. An analysis of the data obtained, along with literature data on the heat capacity, magnetic losses, and the ultrasound velocity, indicates that the various physical quantities demonstrate similar temperature dependences in the vicinity of the transition, which corroborates the conclusion on the universality of the critical behavior in NaV₂O₅. Deviations from the predictions of the standard theory of second-order phase transitions were found, such as the asymmetry of the critical behavior above and below the transition and the presence of an anomalous base line.     

A quantum mechanics-based approach to model incident-induced dynamic driver behavior

A better understanding of the psychological factors influencing drivers, and the resulting driving behavior responding to incident-induced lane traffic phenomena while passing by an incident site is vital to the improvement of road safety. This paper presents a microscopic driver behavior model to explain the dynamics of the instantaneous driver decision process under lane-blocking incidents on adjacent lanes. The proposed conceptual framework decomposes the corresponding driver decision process into three sequential phases: (1) initial stimulus, (2) glancing-around car-following, and (3) incident-induced driving behavior. The theorem of quantum mechanics in optical flows is applied in the first phase to explain the motion-related perceptual phenomena while vehicles approach the incident site in adjacent lanes, followed by the incorporation of the effect of quantum optical flows in modeling the induced glancing-around car-following behavior in the second phase. Then, an incident-induced driving behavior model is formulated to reproduce the dynamics of driver behavior conducted in the process of passing by an incident site in the adjacent lanes. Numerical results of model tests using video-based incident data indicate the validity of the proposed traffic behavior model in analyzing the incident-induced lane traffic phenomena. It is also expected that such a proposed quantum-mechanics based methodology can throw more light if applied to driver psychology and response in anomalous traffic environments in order to improve road safety.     

Uncovering the complex behavior of hydrogen in Cu2O

The behavior of hydrogen in p-type Cu(2)O has been reported to be quite unusual. Muon experiments have been unable to ascertain the preferential hydrogen site within the Cu(2)O lattice, and indicate that hydrogen causes an electrically active level near the middle of the band gap, whose nature, whether accepting or donating, is not known. In this Letter, we use screened hybrid-density-functional theory to study the nature of hydrogen in Cu(2)O, and identify for the first time the "quasiatomic" site adopted by hydrogen in Cu(2)O. We show that hydrogen will always act as a hole killer in p-type Cu(2)O, and is one likely cause of the low performance of Cu(2)O solar cell devices.     

A model for the metal-to-insulator transition in V2O3

The metal-to-insulator transition in V₂O₃ is described by a model that is based on the electronic band structure of this material. The vanadium 3d-t _2g band decomposes in the trigonal symmetry into two bands, a _1g and e _π. The a _1g band consists of orbitals connecting pairs of c-axis neighbouring atoms, while the e _π band consists of orbitals in the plane perpendicular to the c-axis. The change in distance between c-axis neighbours changes the nature of the a _1g band from molecular (delocalized) to atomic (localized). The localization of the a _1g electrons causes through the atomic exchange interaction also the localization of the e _π electrons, and this localization creates a gap in the e _π band which causes the material to become insulating. This model is treated in the Hartree-Fock approximation (the ‘Excitonic’ model) at zero and finite temperatures, and various aspects of the transition, such as changes in the c/a ratio, the creation of magnetic moments, changes in covalency, the effect of pressure and the order of the transition, are investigated.     

Evidence for a doubly magic O

The decay energy spectrum for neutron unbound states in ²⁴O (Z=8$Z=8$, N=16$N=16$) has been observed for the first time. The resonance energy of the lowest lying state, interpreted as the ²⁺$2^{+}$ level, has been observed at a decay energy above 600 keV. The resulting excitation energy of the ²⁺$2^{+}$ level above 4.7 MeV, supplies strong evidence that ²⁴O is a doubly magic nucleus. The data is also consistent with the presence of a second excited state around 5.33 MeV which can be interpreted as the ¹⁺$1^{+}$ level.