Gold nanorods (AuNRs) with different aspect ratios were prepared by the seed-mediated growth method and combined with three carbon-based nanomaterials of multiple dimensions (i.e., zero-dimensional (0D) carbon black (CB), onedimensional (1D) carbon nanotubes (CNTs), and two-dimensional (2D) graphene oxide (GO)). The AuNR/carbon-based nanomaterial hybrids were utilized in dynamic surface-enhanced Raman scattering (D-SERS). First, cetyltrimethylammonium bromide (CTAB) was used to stabilize and coat the AuNRs, enabling them to be dispersed in water and conferring a positive charge to the surface. AuNR/carbon-based nanomaterial hybrids were then formed via electrostatic attraction with the negatively charged carbon-based nanomaterials. Subsequently, the AuNR/carbon-based nanomaterial hybrids were utilized as large-area and highly sensitive Raman spectroscopy substrates. The AuNR/GO hybrids afforded the best signal enhancement because the thickness of GO was less than 5 nm, which enabled the AuNRs adsorbed on GO to produce a good three-dimensional hotspot effect. The enhancement factor (EF) of the AuNR/GO hybrids for the dye molecule Rhodamine 6G (R6G) reached 1 × 10 7 , where the limit of detection (LOD) was 10 −8 M. The hybrids were further applied in D-SERS (detecting samples transitioning from the wet state to the dry state). During solvent evaporation, the system spontaneously formed many hotspots, which greatly enhanced the SERS signal. The final experimental results demonstrated that the AuNR/GO hybrids afforded the best D-SERS signal enhancement. The EF value for R6G reached 1.1 × 10 8 after 27 min, with a limit of detection of 10 −9 M at 27 min. Therefore, the AuNR/GO nanohybrids have extremely high sensitivity as molecular sensing elements for SERS and are also very suitable for the rapid detection of single molecules in water quality and environmental management.

This paper presents the design of a hybrid-excitation-type DC brush motor, simulation and analysis of a commercially available diesel generator starter, and use of the finite-element analysis software, Maxwell 3D, to develop the motor model. Moreover, an improvement is proposed for magnet fixing and compared with the traditional dovetail groove design. Magnet fixation via the splicing method effectively mitigates magnetic saturation; therefore, a power density analysis is performed to demonstrate that the proposed improved design can increase the power density of the magnet per unit volume. Additionally, this work involves another structural improvement, i.e., the hybrid-excitation-type optimization design, along with the use of the Taguchi algorithm to optimize the power of a part of the stator structure; variance analysis and sensitivity are also considered. The analyses justify the selection of control factors for the optimization design. At a rated speed of 3,400 rpm, the output power of the motor increases by 25.1% relative to the prototype. Considering the economic benefits and applications to automobile engines in product development, the new motor configuration enables performance improvements without increasing the weight of the car body.

Wind power is an important source of green power. The equipment, generators, and power systems are all determining factors of equipment efficiency. High efficiency generators of medium and small size are widely used in daily life. Cogging torque is a major issue affecting generator efficiency. This paper proposes an optimized design for permanent-magnet synchronous generators using arc-shaped magnets to reduce cogging torque. The proposed approach improves performance significantly.

In this research, numerical simulation is adopted to study the cooling characteristic of a bracket-type heat sink assembly. Analysis on thermal/fluid fields are used to justify the physical mechanisms inducing the excessive heat dissipation and temperature rise. In order to enhance the cooling capacity of the heat sink assembly, two types of vortex generator, flow-up and flow-down were used to create the turbulent flow for increasing the contact opportunitybetween fluid and plate fin.Also, thermal resistance is used to evaluate the cooling capacity of the heat sink assembly in this work. As a result, the numerical simulations show thatapparent reductions on source temperature (from 348.0K to 346.2K) and thermal resistance (from 0.266 K/W to 0.253 K/W) are observed for a 150W power input. Besides, significant improvement on the heat concentrated phenomenon anduniform temperature distribution were acquired after installing the vortex generators.Furthermore,a larger longitudinal flow was generated when the flow-up type vortex generator was mounted; therefore the temperature distribution is more uniform than that of the flow-downtype. Clearly, the cooling capacity of heat sink assemblyis enhanced since the fluid is guided to the heat concentrated area when theflow-down vortex generators are adopted.

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