[en] We have given a multiple-cycle quantum interference model and obtained magnetoresistance (MR) expression in the framework of weak localization. The MR expression based upon finite phase-breaking length L_φ can well explain several experimental results about distinct negative magnetoresistance of carbon nanotubes. The higher-order oscillation peaks with magnetic flux existing in the MR can also be explained consistently by our model. And a new method to measure the phase-breaking length L_φ of the carbon nanotubes has been proposed

[en] The technology of underwater laser imaging has very important practical value at ocean exploitation such as underwater reconnaissance, target recognition, but its imagery is usually affected by speckle noise. A large number of background noise are brought to underwater laser image for the reasons of absorption and scattering of water, which is also the cause of noises and low contrast of the underwater images. In order to improve the effect of the images, digital image processing techniques are introduced. The result of underwater image processing acts as the input of feature extraction and recognition of the underwater objects. Histogram equalization, contrast enhancement, smoothing filtering are applied to process the blurry underwater laser images. The results of the experiment show these application of Matlab are effective and applicable. (authors)

[en] In this paper, we use the ''complexity equals action'' (CA) conjecture to discuss growth rate of the complexity in a charged AdS-Vaidya black hole formed by collapsing an uncharged spherically symmetric thin shell of null fluid. Using the approach proposed by Lehner et al., we evaluate the action growth rate and the slope of the complexity of formation. Then, we demonstrate that the behaviors of them are in agreement with the switchback effect for the light shock wave case. Moreover, we show that to obtain an expected property of the complexity, it is also necessary for the CA conjecture to add the particular counterterm on the null boundaries. (orig.)

[en] The hysteresis tuning is of great significance before the two-dimensional (2D) molybdenum disulfide (MoS_2) field-effect transistors (FETs) can be practically used in the next-generation nanoelectronic devices. In this paper, a simple and effective annealing method was developed to tune the hysteresis voltage in 2D MoS_2 transistors. It was found that high temperature (175 °C) annealing in air could increase the hysteresis voltage from 8.0 V (original device) to 28.4 V, while a next vacuum annealing would reduce the hysteresis voltage to be only 2.0 V. An energyband diagram model based on electron trapping/detrapping due to oxygen adsorption is proposed to understand the hysteresis mechanism in multilayer MoS_2 FET. This simple method for tuning the hysteresis voltage of MoS_2 FET can make a significant step toward 2D nanoelectronic device applications.

[en] Bañados et al. (BSW) found that Kerr black holes can act as particle accelerators with collisions at arbitrarily high center-of-mass energies. Recently, collisions of particles with spin around some rotating black holes have been discussed. In this paper, we study the BSW mechanism for spinning particles by using a metric ansatz which describes a general rotating black hole. We notice that there are two inequivalent definitions of center-of-mass (CM) energy for spinning particles. We mainly discuss the CM energy defined in terms of the worldline of the particle. We show that there exists an energy-angular momentum relation e=Ω${}_h$j that causes collisions with arbitrarily high energy near extremal black holes. We also provide a simple but rigorous proof that the BSW mechanism breaks down for nonextremal black holes. For the alternative definition of the CM energy, some authors find a new critical spin relation that also causes the divergence of the CM mass. However, by checking the timelike constraint, we show that particles with this critical spin cannot reach the horizon of the black hole. Further numerical calculation suggests that such particles cannot exist anywhere outside the horizon. Our results are universal, independent of the underlying theories of gravity.

[en] Many low-level environmental agents are able to induce an increased resistance to subsequent mutagenic effects induced by ionizing radiation. In this paper, an induced cytogenetic adaptation to radiation in human lymphocytes was studied with mild hyperthermia as the adaptive treatment and compared with that induced by low-dose radiation. We found that this adaptation could be induced not only in PHA-stimulated human lymphocytes (at 14, 38 and 42 h after addition of PHA), but also in unstimulated G₀-phase cells (before addition of PHA) by mild hyperthermia (41 degrees C for 1 h) as well as 50 mGy X rays. When the two adaptive treatments were combined, no additive effects on the magnitude of the adaptation induced were observed, suggesting that low-dose radiation and hyperthermia may share one mechanism of induction of adaptation to cytogenetic damage. Some mechanisms which may be involved in the induction of adaptation to cytogenetic damage by low-dose radiation are discussed and compared with the effects of mild hyperthermia in inducing thermotolerance and radioresistance. 56 refs., 4 figs., 3 tabs

[en] Using the Schwinger boson method, a detailed phase diagram of Manganese oxides at low temperatures is obtained. The magnetic transition and spin correlation are studied, based on an electron-electron correlation mechanism. The results indicate that there are antiferromagnetic (AF), spiral (SP), ferromagnetic (FM) and canted (CN) states when T→0. With temperature increasing, a paramagnetic (PM) state appears. The critical temperatures T_D and T_Q vary with the doping concentration. The spin-spin correlation function is also obtained

[en] The Su-Schrieffer-Heeger model has been extended and solved numerically to study the electronic structures of seven C₈₀ fullerene isomers. Then we analyze the electronic properties of the seven isomers and discuss the difference among their electronic structure. It is found that phonons considered in the SSH model induce different results from recent theoretical studies. We compare our results with those obtained with other methods and discuss the difference. (orig.)

[en] Human lymphocytes pre-treated by heat (41 degree C 1 h), low dose irradiation (50 mGy), or both low dose radiation and heat together, became less susceptible to chromatid damage induced by subsequent high dose of X-rays. Either heat or low dose X-rays could significantly reduce the yield of chromatid aberrations, but the magnitude of adaptive response was not enhanced when combined treatment with low dose radiation and heat were used. The results implied that the mechanism of adaptive response induced by low dose X-rays was as the same of the mechanism of adaptive response induced by hyperthermia, which may be related with some protective proteins

[en] In this paper, we use the "complexity equals action" (CA) conjecture to explore the switchback effect in the strongly-coupled quantum field theories with finite N and finite coupling effects. In the perspective of holography, this is equivalent to evaluating the CA complexity in a Vaidya geometry equipped with a light shockwave for a higher curvature gravitational theory. Based on the Noether charge formalism of Iyer and Wald, we obtain the slope of the complexity of formation in the small- and large-time approximations. By circuit analogy, we show that our results concur with the switchback effect of the quantum system. These results show that the switchback effect is a general feature of the CA complexity in stationary black holes and its existence is independent of the explicit gravitational theory as well as spacetime background. From the viewpoint of AdS/CFT, this also implies that the switchback effect is a general feature of the thermofield double state in the strongly-coupled quantum field systems with finite N and finite coupling effects. Moreover, we also illustrate that unlike the late-time complexity growth rate, the counterterm plays an important role in the study of the switchback effect.