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Slow light with high group index and wideband is achieved in photonic crystal coupled-resonator optical waveguides (PC-CROWs). According to the eye-shaped scatterers and various microcavities, saddle-like curves between the normalized frequency f and wave number k can be obtained by adjusting the parameters of the scatterers, parameters of the coupling microcavities, and positions of the scatterers. Slow light with decent flat band and group index can then be achieved by optimizing the parameters. Simulations prove that the maximal value of the group index is > 104, and the normalized delay bandwidth product within a new varying range of n g > 102 or n g > 103 can be a new and effective criterion of evaluation for the slow light in PC-CROWs.

Background Congenital left atrial appendage aneurysm (LAAA) is a rare cardiac anomaly with potentially serious complications, including life-threatening systemic thromboembolism, atrial tachyarrhythmia, and cardiac dysfunction. Currently, early surgical intervention is generally recommended to prevent these complications. Case presentation We present a case of congenital giant LAAA in a female patient who successfully completed pregnancy and underwent caesarean section with no obvious complications. Surgical resection of the LAAA was performed 3 years later, at the onset of chest pain resulting from compression of adjacent cardiac structures by the LAAA. Conclusion Surgical resection is recommended for the majority of patients with LAAA because of potential LAAA-related severe outcomes. However, clinical monitoring may be an optional strategy for asymptomatic patients without intra-atrial thrombus or other complications. Precise evaluation with echocardiography and brain magnetic resonance imaging is valuable for the subsequent management of LAAA.

Since Tian Jun proposed the difference expansion embedding technique, based on which, many reversible watermarking techniques were proposed. However, these methods do not perform well when the payload is high. In this paper, we proposed an expandable difference threshold controlled scheme for these three methods. Experiments show that our scheme improves the performance of these three methods for heavy payload.

Hepatic computed tomography (CT) images with Gabor function were analyzed. Then a threshold-based classification scheme was proposed using Gabor features and proceeded with the retrieval of the hepatic CT images. In our experiments, a batch of hepatic CT images containing several types of CT findings was used and compared with the Zhao’s image classification scheme, support vector machines (SVM) scheme and threshold-based scheme.

In the study of reaction kinetics between hydrogen and hydriding alloys, what is the most important is to obtain intrinsic kinetic data. The hydriding kinetics of 0.5 g La1.5Ni0.5Mg17 sample in the two-phase (α-β) region was investigated as a function of temperature and pressure in the ranges 553–573 K and 0.256–0.992 MPa H2 respectively. Mathematical analyses of the time-dependent hydrogen absorption curves indicate agreement with Jander diffusion model, [1 − (1 − ξ)1/3]2 = k(T, P)t, which suggests that the rate-controlling step for hydrogen absorption is three-dimensional diffusion. An apparent activation energy for such diffusion process of 83 ± 1 kJ/mol H2 has been obtained from the absorption data.

A new nano-ternary Mg–8 mol% LaNi0.5 was prepared by melted and subsequent mechanical alloying technique for hydrogen storage. It was found from our experiments that, this kind of alloy had superior hydriding/dehydriding characteristics in comparison with conventional materials for hydrogen storage. It possessed large hydrogen capacity at a lower temperature, which could absorb 4.55–7.01 mass% H under 3 MPa hydrogen pressure and desorb 4.40–6.90 mass% H under 0.0133 MPa in 600 s above 423 K without any activation requirement drawn from our pressure-composition isotherm and kinetic experiments. Through the x-ray diffraction and transmission electron microscopy experiments, we further found that these superior characteristics could be attributed to the multiphase structure and a catalytic effect of LaH3 and Mg2Ni that were formed in the material preparation of mechanical alloying process. Finally, based on these data the relationships between equilibrium pressure of hydrogen and temperature were obtained, they were lgp(0.1 MPa) = −3985/T + 7.188(553 K ⩽ T ⩽ 573K) for hydriding and lgp(0.1 MPa) = −3804/T + 6.770 (553 K ⩽ T ⩽ 573 K) for dehydriding.

The hydrogen absorption/desorption (A/D) kinetics of hydrogen storage alloys Mg1.9Al0.1Ni prepared by hydriding combustion synthesis in two-phase (α-β) region in the temperature range from 523 to 573 K have been investigated. The hydriding/dehydriding (H/D) reaction rate constants were extracted from the time-dependent A/D curves. The obtained hydrogen A/D kinetic curves were fitted using various rate equations to reveal the mechanism of the H/D processes. The relationships of rate constant with temperature were established. It was found that the three-dimensional diffusion process dominated the hydrogen A/D. The activation energies of Mg1.9Al0.1Ni are 52 ± 2 and 48 ± 1 kJ/mol H2 for the H/D processes smaller than that of Mg2Ni, which can be explained that the improvement of H/D reaction kinetics in Mg2Ni by using additive Al.