In this work, the self-collimating phenomenon in two-dimensional rhombic-lattice photonic crystals is discussed in detail. The equi-frequency contours of a rhombic-lattice rod-type photonic crystal structure are calculated with the plane wave expansion method for different lattice angles and rod radii. A broad range of flat and open equi-frequency contours is found. A rhombic-lattice photonic crystal made of 301 × 21 silicon rods (n = 3.5) in air is presented as an illustration to demonstrate the broadband all-angle self-collimation. The bandwidth for all-angle self-collimation is verified to be 17.42% of the central frequency by simulations based on the finite-difference time-domain method. The all-angle self-collimation is found to be polarization-independent and the frequency for simultaneous TM and TE all-angle self-collimation is identified and verified by finite-difference time-domain simulations.

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The study aimed to investigate the effects of loving-kindness meditation on positive emotions, intragroup interactions, and complex understanding of others. A total of 50 freshmen not receiving any training in meditation intervention were randomly divided into the meditation group (25 subjects) and the control group (25 subjects). The meditation group was implemented with group meditation intervention for 4 weeks, three times a week, about 30 minutes each time. The results revealed that the effect sizes in interpersonal interaction and complex understanding of others in the meditation group were both above 0.8, indicating strong effects. It was concluded that loving-kindness meditation can effectively improve positive emotions, interpersonal interactions, and complex understanding of others in college students.

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