Abstract: A graphene quantum dots-gadolinium ion chelate (Gd@GQDs) nanomaterial with hydrophilic groups on the surface has a preparation method that includes: preparing graphene oxide by using a Hummers method; subsequently, subjecting the graphene oxide to heating, oxidation, and purification to obtain pure graphene quantum dots; and finally, chelating the graphene quantum dots with Gd3+ to form stable Gd@GQDs. The Gd@GQDs is easily dispersed in water, phosphate buffered solution (PBS), biological medium and other aqueous system, has good biocompatibility and low cytotoxicity, shows an excellent T1-weighted contrast performance in a 1.5-Tesla magnetic resonance testing system, and has a relaxation rate r1 as high as 72 mM?1s?1, the value of r1 being 20 times higher than that of the current commercial T1-weighted magnetic resonance imaging contrast agent Gd-DTPA.

Abstract: Copper ion-doped carbon dots (Cu-CDs) and a preparation method thereof are disclosed. The preparation method includes the following steps: using copper nitrate as a dopant to generate a complex of polyacrylic acid and copper ions as a precursor by an in situ polymerization; standing overnight, and performing repeated suction filtration to collect filter residues; then, performing pyrolysis and carbonization to generate carbonized products, dispersing in ultrapure water, taking a supernatant, and then performing extraction and purification to obtain the CDs. When the Cu-CDs prepared by the present invention are used in photodynamic therapy, photothermal/photodynamic synergistic therapy is not required, and the Cu-CDs are suitable for the therapeutic process of skin cancer, lung cancer, pancreatic cancer, esophageal cancer, brain glioma, as well as some skin diseases and ophthalmological diseases.

Abstract: A voice coil (4, 4a . . . 4f) for an electrodynamic actuator (6a . . . 6c) is disclosed, which comprises a plurality of conductive open annular strips (15, 15A . . . 15n, 15a . . . 15h) stacked over one another with insulation layers (18) in-between, wherein ends (Ea . . . Eh) of adjacent strips (15, 15A . . . 15n, 15a . . . 15h) overlap in an overlap-ping zone (ZO) when viewed in a direction parallel to a coil axis (CA) and wherein adjacent strips (15, 15A . . . 15n, 15a . . . 15h) are electrically connected to each other in a connection zone (ZC) within the overlapping zone (ZO). Ends (Ea . . . Eh) of the conductive strips (15, 15A . . . 15n, 15a . . . 15h) are embodied as non-straight ends, and positions (P) of connection zones (ZC), which connect different conductive strips (15, 15A . . . 15n, 15a . . . 15h), vary in a direction transversal to the circumferential direction (CD) in the overlapping zone (ZO). Moreover, a manufacturing meth-od for such a voice coil (4, 4a . . .

Abstract: The invention relates to a speaker (1) comprising a coil arrangement (2) with at least two voice coils (3a, 3b), a magnet system (4) and a membrane (10) being fixed to the coil arrangement (2) and the magnet system (4). The membrane (10) has a first compliance (c1) and together with the coil arrangement (2) causes a first resonance frequency (fres1) for an oscillation of the membrane (10). In addition, the speaker (1) comprises a second connector (14, 17, 17a, 17b, 24, 25a, 25b) with a second compliance (c2), which interconnects the voice coils (3a, 3b). The second connector (14, 17, 17a, 17b, 24, 25a, 25b) together with the voice coils (3a, 3b) causes a higher second resonance frequency (fres2) for the oscillation of the membrane (10). Moreover, the invention relates to an electronic sound signal circuit (18), which is designed to output coil signals (SO1, SO2) having a frequency dependent phase shift (?).

Abstract: A method for manufacturing an electrodynamic acoustic transducer is disclosed. The electrodynamic acoustic transducer comprises a frame and/or a housing, a membrane, at least one coil and a magnet system, wherein the coil, in a cross sectional view with a coil axis being part of the sectional plane, comprises a plurality of conductive layers formed by an electrical conductor of the coil. The electrical conductor has a rectangular cross section in said cross sectional view, wherein a longer side of the rectangular cross section is substantially perpendicular to the loop axis. According to this method, a stack of conductive layers is made from the electrical conductor by stacking of separate pieces of the electrical conductor and electrically connecting the stacked separate pieces and/or by folding of the electrical conductor.

Abstract: A method of manufacturing a voice coil (1a . . . 1d) is disclosed, wherein windings (4a . . . 4g) in a first section (B1) are arranged one above the other and are arranged next to each other in a second section (B2) when viewed in said cross sectional plane (D). In a first step, a first and a second winding (4a, 4a?, 4b) of the windings (4a . . . 4g) are arranged over one another but offset sideways to each other in the second section (B2). In a second step, the first winding (4a, 4a?) is moved into a height position of the second winding (4b) in the second section (B2) by pressing and/or folding. Moreover, an electrodynamic actuator (17a . . . 17c), comprising a voice coil (1a . . . 1d) of the above kind is disclosed. Finally, an electrodynamic transducer (32a, 32b), a speaker (21) and an output device comprising such an electrodynamic actuator (17a . . . 17c) is disclosed.

Abstract: An electrodynamic acoustic transducer, is disclosed, which comprises a frame and/or a housing, a membrane, at least one coil and a magnet system. The coil in a cross sectional view with a coil axis being part of the sectional plane comprises a plurality of conductive layers formed by an electrical conductor of the coil. The electrical conductor has a rectangular cross section in said cross sectional view, wherein a longer side of the rectangular cross section is substantially perpendicular to the loop axis. Furthermore, a method for manufacturing an electrodynamic acoustic transducer of the proposed kind is disclosed. According to this method, a stack of conductive layers is made from the electrical conductor by stacking of separate pieces of the electrical conductor and electrically connecting the stacked separate pieces and/or by folding of the electrical conductor.

Abstract: A graphene quantum dots-gadolinium ion chelate (Gd@GQDs) nanomaterial with hydrophilic groups on the surface has a preparation method that includes: preparing graphene oxide by using a Hummers method; subsequently, subjecting the graphene oxide to heating, oxidation, and purification to obtain pure graphene quantum dots; and finally, chelating the graphene quantum dots with Gd3+ to form stable Gd@GQDs. The Gd@GQDs is easily dispersed in water, phosphate buffered solution (PBS), biological medium and other aqueous system, has good biocompatibility and low cytotoxicity, shows an excellent T1-weighted contrast performance in a 1.5-Tesla magnetic resonance testing system, and has a relaxation rate r1 as high as 72 mM?1s?1, the value of r1 being 20 times higher than that of the current commercial T1-weighted magnetic resonance imaging contrast agent Gd-DTPA.

Abstract: Copper ion-doped carbon dots (Cu-CDs) and a preparation method thereof are disclosed. The preparation method includes the following steps: using copper nitrate as a dopant to generate a complex of polyacrylic acid and copper ions as a precursor by an in situ polymerization; standing overnight, and performing repeated suction filtration to collect filter residues; then, performing pyrolysis and carbonization to generate carbonized products, dispersing in ultrapure water, taking a supernatant, and then performing extraction and purification to obtain the CDs. When the Cu-CDs prepared by the present invention are used in photodynamic therapy, photothermal/photodynamic synergistic therapy is not required, and the Cu-CDs are suitable for the therapeutic process of skin cancer, lung cancer, pancreatic cancer, esophageal cancer, brain glioma, as well as some skin diseases and ophthalmological diseases.

Abstract: A method for manufacturing an electrodynamic acoustic transducer is disclosed. The electrodynamic acoustic transducer comprises a frame and/or a housing, a membrane, at least one coil and a magnet system, wherein the coil, in a cross sectional view with a coil axis being part of the sectional plane, comprises a plurality of conductive layers formed by an electrical conductor of the coil. The electrical conductor has a rectangular cross section in said cross sectional view, wherein a longer side of the rectangular cross section is substantially perpendicular to the loop axis. According to this method, a stack of conductive layers is made from the electrical conductor by stacking of separate pieces of the electrical conductor and electrically connecting the stacked separate pieces and/or by folding of the electrical conductor.

Abstract: An electrodynamic acoustic transducer, is disclosed, which comprises a frame and/or a housing, a membrane, at least one coil and a magnet system. The coil in a cross sectional view with a coil axis being part of the sectional plane comprises a plurality of conductive layers formed by an electrical conductor of the coil. The electrical conductor has a rectangular cross section in said cross sectional view, wherein a longer side of the rectangular cross section is substantially perpendicular to the loop axis. Furthermore, a method for manufacturing an electrodynamic acoustic transducer of the proposed kind is disclosed. According to this method, a stack of conductive layers is made from the electrical conductor by stacking of separate pieces of the electrical conductor and electrically connecting the stacked separate pieces and/or by folding of the electrical conductor.