Optical excitation of optically inactive photonic band modes

At the point Γ of the Brillouin zone of photonic crystals (PCs), there are many photonic band (PB) states that do not couple to the incoming plane wave beams. This paper investigates how to excite these optically inactive PB (OIPB) modes in slab PCs by using optical means. Three methods are proposed, using a prism, traveling charges and focused laser pulses, each making use of evanescent light to excite OIPBs. It is concluded that to accumulate photons in an OIPB, sequential passing of bunched charges or intermittent irradiation of focused laser pulses is effective. The effect of the lateral size of the practical PC slabs is also discussed and it is found that the conclusions for an ideal system of infinite size still work if the lateral size is order of magnitudes larger than the PC lattice constant.     

Smith-Purcell radiation from a charge running near the surface of a photonic crystal

Smith-Purcell radiation from a charge running near a photonic crystal is calculated for a slab system of a periodic array of dielectric spheres, with the photonic band effect taken into account exactly. The radiation spectrum has a series of resonantly enhanced structures, which are shown to arise accompanying the excitation of the photonic bands. It is also shown that the overall intensity of the emission band does not depend very strongly on the slab thickness but the height of the resonant peaks increases progressively with thickness due to the enhanced Q value of excited photonic bands.     

Influence of Moderate Temperature Treatment under Oxidation Atmosphere on Acidic Site Distribution of γ-Alumina

In order to elucidate the role of acidity in reaction of selective NO reduction by hydrocarbons in oxygen-rich circumstances, a commercial -alumina was treated under atmosphere at moderate temperature range and the acidic sites of treated alumina were determined by differential NH3 adsorption heat at 473 K. The alumina has little impurity of Na, Fe, Si. The BET surface area and average pore width are 350 m2/g and 4 nm respectively. Air treatment at moderate temperature has no serious effect on the total amount of acidic sites above 70 kJ/mol, but influences the acidic site distribution at the initial and the tail energy sides. Treatment at higher temperature gives rise to a higher initial adsorption heat due to activation of alumina surface. Disappearance of carbon-contained species and appearance of distinct surface hydroxyl groups under air treatment above 673 K are plausibly observed by FT-IR. Degree of dehydration has a tremendous effect on development of Brönsted acidic sites. The relationship of changes in acidic site distribution at moderate temperature and De-NOx activity at the same temperature was discussed.     

Annealing effect on the superconductivity of In2O3–ZnO thin films

We have investigated the relation among ρ–T characteristics, superconductivity, annealing conditions and the crystallinity of polycrystalline (In₂O₃)_1−x–(ZnO)_x films. We annealed as-grown amorphous films in air by changing annealing temperature and time. It is found that the films annealed at 200 °C or 300 °C for a time over 0.5 h shows the superconductivity. Transition temperature T_c and the carrier density n are T_c < 3.3 K and n ≈ 10²⁵–10²⁶ m⁻³, respectively. Investigations for films with x = 0.01 annealed at 200 °C have revealed that the T_c, n and crystallinity depend systematically on annealing time. Further, we consider that there is a suitable annealing time for sharp resistive transition because the transition width becomes wider with longer annealing times. We studied the upper critical magnetic field H_c2(T) for the film with different annealing time. From the slope of dH_c2/dT for all films, we have obtained the resistivity ρ dependence of the coherence length ξ(0) at T = 0 K.     

Bioactive constituents from Chinese natural medicines. XXVI. Chemical structures and hepatoprotective effects of constituents from roots of Rhodiola sachalinensis

The methanolic extract from the roots of Rhodiola sachalinensis was found to show a protective effect on D-galactosamine-induced cytotoxicity in primary cultured mouse hepatocytes. From the methanolic extract, five new glycosides, two monoterpene glycosides, two flavonol bisdesmosides, and a cyanogenic glycoside, were isolated together with 34 known compounds. The structures of new constituents were elucidated on the basis of chemical and physicochemical evidence. In addition, the principal constituents, sachalosides III and IV, rhodiosin, and trans-caffeic acid, displayed hepatoprotective effects.     

Elementaranalyse

Ohne Zusammenfassung     

Corresponding states in the smectic-A phase

In the last few years, experimental data of many different sources has been gathered to show that order parameter curves of essentially all nematic liquid crystals (NLCs) compounds can be reduced to a single and universal curve of the corresponding states; experimental data of an impressive number of different nematic compounds has been linearly rescaled in such a way that all them coalesced in a single curve. The surprising novelty observed on NLCs is that this universal behaviour is not restricted to the neighbourhoods of a critical region, as is usually expected from critical phenomena, but it covers the entire domain of the nematic phase, from the nematic isotropic temperature to the nematic crystalline temperature. The aim of this paper is to study the statistical mechanics fundamentals of this behaviour and show that it is a consequence of the universality of the angular part of the potential of the interaction between the particles composing the liquid crystal (LC). We will illustrate this behaviour presenting evidences that it can be found on the smectic-A phase.     

Relativistic calculation of nuclear magnetic shielding tensor including two-electron spin-orbit interactions

A relativistic calculation of nuclear magnetic shielding tensor including two-electron spin-orbit interactions is performed. In order to reduce the computational load in evaluating the two-electron relativistic integrals, the charge density is approximated by a linear combination of the squares of s-type spatial basis functions. Including the two-electron spin-orbit interaction effect is found to improve the calculation results.     

Chaos in numerical analysis of ordinary differential equations

The discretisation of the ordinary nonlinear differential equation $\text{d}\text{y}\text{d}\text{t}\text{= y(1?y)}$ by the entral difference scheme is studied for fixed mesh size. In the usual numerical computation, this method produces some “ghost solution” for the long range calculation. Regarding this discretisation as a dynamical system in R², these pathological behaviors are shown to be a kind of “chaos” in the dynamical system for any mesh size. Moreover, some combination of the central difference scheme and the Euler's scheme is studied for the above equation. It gives some motivation for Hénon's model. The usual discretisation of a second order differential equation are studied also. It gives some chaotic behaviors numerically which is similar to the behavior of the orbits of the system of differential equations proposed by Hénon-Heiles.