Abstract: The present disclosure provides an acoustic output device. The acoustic output device may comprise a bone conduction speaker configured to generate bone conduction acoustic waves. The acoustic output device may also comprise an air conduction speaker configured to generate air conduction acoustic waves, the air conduction speaker being independent of the bone conduction speaker. The acoustic output device may further comprise at least one housing configured to accommodate the bone conduction speaker and the air conduction speaker.

Abstract: A buffered balanced type mobile primary-secondary air conditioner system wherein three working media are used in primary-secondary air conditioner system. The first working medium is a compressor refrigeration working medium, the second working medium is an energy storage and heat transfer working medium shared by the primary machine and the secondary machine, and the third working medium is a secondary machine energy storage and heat transfer working medium. This scheme establishes a buffer balance zone between the primary machine and the secondary machine to store the second working medium.

Abstract: A metamaterial having a negative refractive index is presented, which has a dielectric carrier material (12; 48), first electrically conductive sections (14.1, 14.2, 14.3, 14.4) and second electrically conductive sections (16.1, 16.2). The metamaterial is distinguished by the fact that the dielectric carrier material (12; 48) is realized as a volume which consists of one piece and which has at least one inner area which is prestructured by positive or negative rib or mesa structures (52.1, 52.2) in the dielectric carrier material (48) and is covered with first sections (14.1, 14.2, 14.3, 14.4) and second sections (16.1, 16.2) in such a way that the first sections form capacitive series impedances upon illumination with an electromagnetic wave having a specific propagation direction and polarization, while the second sections are arranged in such a way that they form inductive shunt impedances upon the illumination.

Abstract: A metamaterial having a negative refractive index is presented, which has a dielectric carrier material (12; 48), first electrically conductive sections (14.1, 14.2, 14.3, 14.4) and second electrically conductive sections (16.1, 16.2). The metamaterial is distinguished by the fact that the dielectric carrier material (12; 48) is realized as a volume which consists of one piece and which has at least one inner area which is prestructured by positive or negative rib or mesa structures (52.1, 52.2) in the dielectric carrier material (48) and is covered with first sections (14.1, 14.2, 14.3, 14.4) and second sections (16.1, 16.2) in such a way that the first sections form capacitive series impedances upon illumination with an electromagnetic wave having a specific propagation direction and polarization, while the second sections are arranged in such a way that they form inductive shunt impedances upon the illumination.