SummaryIn this study, a demand-based optimal design method is proposed for an oscillator (a single-degree-of-freedom system) with a parallel-layout viscous inerter damper (PVID). The proposed design method overcomes some deficiencies of the existing method, which is based on the fixed-point theory and is mainly suitable for tuned mass dampers. Moreover, for the fixed-point method, the inherent damping of the primary structure is neglected, and the global optimal solution cannot be obtained.The proposed method can obtain a more rational and practical design for the actual design by minimizing both the response and the cost. The design problem of a PVID-equipped oscillator is transformed into a multi-objective optimization problem that can be solved using the ε-constraint approach, which is consistent with the concept of demand-based design. The dynamic response of the oscillator and the force of the PVID (i.e., the cost factor) are evaluated according to theories of random vibration to reduce the number of calculations required. A computer program is developed to perform demand-based parametric design of a PVID-equipped oscillator. Several design cases were examined under different excitation conditions using the computer program, and dynamic time history analyses were then conducted to verify the designs obtained. The results show that the proposed optimal design method identifies satisfactory designs more effectively than the existing method by obtaining PVID design parameter values that better meet the performance demand and simultaneously minimize the cost. | INTRODUCTIONStructural vibrations induced by earthquake or wind loads can be attenuated by various means, including modifying the stiffness, masses, damping, or shape of the structure, and by providing passive or active counter forces.[1] Among numerous available methods, passive mitigation measures are the most widely used in building and bridge engineering. Passive vibration mitigation involves providing a structure with additional damping by installing dampers, and the effectiveness of damping has been confirmed by extensive scientific studies and practical applications. Many types of dampers are used in the passive vibration mitigation of building structures all over the world, such as metalyield dampers, friction dampers, viscoelastic dampers, viscous fluid dampers, tuned mass dampers, and tuned liquid dampers. The concept of tuned mass dampers dates back to the 1900s, when Frahm [2] introduced a tuned mass damper (TMD) to absorb the energy of vibrations, thereby reducing the amplitudes of motions. Den Hartog [3] modified the original TMD concept in the

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Ga-doped garnet-type Li 7 La 3 Zr 2 O 12 (Ga-LLZO) ceramics have long been recognized as ideal electrolyte candidates for all-solid-state lithium batteries (ASSLBs). However, in this study, it is shown that Ga-LLZO easily and promptly cracks in contact with molten lithium during the ASSLB assembly. This can be mainly ascribed to two aspects: (i) lithium captures O atoms and reduces Ga ions of the Ga-LLZO matrix, leading to a bandgap closure from >5 to <2 eV and a structural collapse from cubic to tetrahedral; and (ii) the in situ-formed LiGaO 2 impurity phase has severe side reactions with lithium, resulting in huge stress release along the grain boundaries. It is also revealed that, while the former process consumes hours to take effect, the latter one is immediate and accounts for the crack propagation of Ga-LLZO electrolytes. A minute SiO 2 is preadded during the synthesis of Ga-LLZO and found effective in eliminating the LiGaO 2 impurity phase. The SiO 2 -modified Ga-LLZO solid electrolytes display excellent thermomechanical and electrochemical stabilities against lithium metals and well-reserved ionic conductivities, which was further confirmed by half-cells and full batteries. This study contributes to the understanding of the stability of garnet electrolytes and promotes their potential commercial applications in ASSLBs.

Mobile ion-enabled phenomena make β-Zn4Sb3 a promising material in terms of the re-entry phase instability behavior, mixed electronic ionic conduction, and thermoelectric performance. Here, we utilize the fast Zn2+ migration under a sawtooth waveform electric field and a dynamical growth of 3-dimensional ionic conduction network to achieve ultra-fast synthesis of β-Zn4Sb3. Moreover, the interplay between the mobile ions, electric field, and temperature field gives rise to exquisite core-shell crystalline-amorphous microstructures that self-adaptively stabilize β-Zn4Sb3. Doping Cd or Ge on the Zn site as steric hindrance further stabilizes β-Zn4Sb3 by restricting long-range Zn2+ migration and extends the operation temperature range of high thermoelectric performance. These results provide insight into the development of mixed-conduction thermoelectric materials, batteries, and other functional materials.