Mechanical stress/strain strongly affects and interacts with ferroelectric and various electronic properties, i.e., "Multi-Physics" coupling. Especially, ferroelectric nanostructures exhibit novel properties distinct from the bulk counterpart. This paper reviews a series of studies on remarkable ferroelectric and multi-physics properties in nanoscale components from first-principles calculations, which are essential for the nonlinear multi-physics couplings due the quantum mechanical effects. The novelty and complexity of ferroelectric nanostructures originate from combinations of the outer shape (e.g., thin film, nano-wire, tube, and dot) and the inner understructure (e.g., grain boundary, domain wall, and lattice distortion). Each shape or understructure alters spontaneous polarization although the influence is restricted within a local area of several nanometers. The multi-physics coupling with mechanical stress/strain not only enhances their influence dramatically and entirely but also brings about novel and unusual ferroelectric properties, such as ferromagnetic-like closure-nanodomains, polarization vortices, improper ferroelectricity, and absence of ferroelectric critical sizes. This paper first classifies these nanostructures into fundamental elements and explains the interplay of them systematically, which provides deeper insights into multi-physics properties in nanostructures. This review simultaneously points out a new direction of "mechanics of materials", which opens the door to exploit and design novel functionalities in the nanoscales.
The limitation of technology to estimate the on-orbit microvibration of a spacecraft is shown in this review paper. At present, the mechanical engineering ability cannot meet the mission requirements and the configuration of the pre-flight ground tests is far from the on-orbit configuration from the microvibration point of view. It is also extremely difficult to correlate the mathematical dynamical model (Finite Element Model (FEM)) exactly to test data up to the mid-frequency range where microvibration can be problematic even if considerable manpower is committed to analyze the correlation. Accordingly, a safety factor of at least single digit range must be introduced as part of disturbance control management.
Author's experience in space engineering was first reviewed. The past 50 years activities include launch vehicles, satellites in commercial and educational areas, space debris, deep space exploration, on-orbit servicing and other advanced systems. Although some of the tasks provided outputs to serve actual space systems, most of other tasks originated or proposed failed to go into real programs. Discontinuation of original proposal is very common in actual space programs. Successful programs also often go through a series of alternations due to engineering, economic or political reasons, and the established systems not necessarily represent ideal ones that have been envisioned in the original thinking. Some remarks from this view point are stated to look into future space endeavors, perhaps in next 50 years.
First, author described the establishment process of the international conference “ICBTT” and the later development briefly. The conference is based on the interdisciplinary domain of liberal arts and science technology, and it was held world's first splendid achievement and epoch-making event. Then, author paid attention to purposes, key words, topics, and deliberated the significance of this international conference. Furthermore, specialties and the interests of the lecturers that were not publicized were investigated. And then, the viewpoint in the papers was confirmed in consideration of those characteristics. By analysing words and the phrases extracted from the papers, author was able to substantiate the usefulness of this international conference “ICBTT”.
We review deviational methods for solving the Boltzmann equation governing phonon transport processes in the context of small-scale, solid-state heat transfer. We briefly discuss the numerical foundations of deviational algorithms as well as basic simulation methodology. Particular emphasis is given to recent developments in the field yielding appreciable efficiency improvements, such as linearized and adjoint formulations, and their applications to complex multiscale problems. Recently developed methods for simulating the ab initio collision operator for applications to phonon transport in novel two-dimensional materials, such as graphene, are also reviewed and discussed.
Micropump is one of critical devices in composing high-performance micro-fluid systems like micro hydraulics, fluid-driven micro machines, micro liquid forced cooling of electrical components, µTAS(Micro total analysis systems), LOC(Lab-on a-chip), micro dosing system and so on. A lot of principles are proposed to develop micropumps in these 30 years. At the same time, many review papers on many kinds of micropumps were published in these 20 years, however, in these 8 years there are little review papers on micropumps, particularly from the point of power density view. Here, first, we survey some recent review articles on the progress of micropumps over the past 25 years. Secondly, we attempt to provide the review on latest trend on micropump researches in these 8 years. Finally, we introduce some powerful micropumps as a power source of micro hydraulics. From the point of view that the micropump can be power source as a micro hydraulics, the state of the art micropumps and their power densities are discussed. Much progress has been made, however, with micropumps suitable for primary applications still not available, it seems that this remains a developing and productive area for future research.
This paper proposes we have to go one step further from Knowledge Engineering and develop Wisdom Engineering in order to cope with the very frequently and extensively changing environments and situations. In order to respond quickly and adaptively to such changes, knowledge should be processed more dynamically. Emotion plays an important role for this purpose in sensing and in making decisions. Further, our world is changing from Closed World to Open World. In a Closed World, experience can be accumulated and is structured into knowledge and the logic of induction and deduction can be applied. But in an Open World, decisions must be made by trials and errors by interacting with the outer world. As the fact emotion comes from the Latin word, movere, it literally means to move out or to act toward the outer world. Motivation comes from the same Latin word. Thus, motivation-action-emotion constitutes a cycle and it plays an important role in trials and errors and in producing dynamic knowledge. Wisdom Engineering is as an integration of Emotion Engineering and Knowledge Engineering and it produces dynamic knowledge, which enables us to interact with the frequent and extensive changes of the outer world more wisely and adaptively and to explore the new frontiers in an Open World.