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Herein, we present the common structural features of a family of semiconducting molecular donor–acceptor (DA) compounds based on alkylated fused-ring thieno-acenes. Crystal structure analyses were conducted for 22 DA compounds of variously substituted benzothieno[3,2-b][1]benzothiophenes (BTBTs), unsubstituted dithieno[3,2-b:2’,3’-d]thiophene, and unsubstituted benzo[1,2-b:4,5-b’]dithiophene as donors, which were combined with 7,7,8,8-tetracyanoquinodimethane (TCNQ) and its fluorinated derivatives (FmTCNQ, m = 0, 1, 2, 4) as acceptors. Fourteen DA compounds of (substituted BTBT)(TCNQ derivative) formed isomorphous layered molecular packing, where the intermolecular stacking arrangements between the planar skeletons of BTBT and TCNQ were common to each other, and the various substituents played supplementary roles. Density functional theory calculations were conducted to investigate the intermolecular forces between π-electron cores along the DA stacks. Dispersion interactions were the dominant intermolecular attraction, showing weak stacking position dependence, while the short-range orbit–orbit interaction was always repulsive, irrespective of stacking. An important finding is that the orbit–orbit interaction has a relatively strong position dependence and leads to common structural features in the DA compounds. We discuss the origin of the isostructural nature of molecular DA compounds, which is crucial in searching for and exploring unique combinations of molecules with superior semiconducting characteristics., Journal of Materials Chemistry C, 10(43), pp.16471-16479; 2022

According to previous theoretical work, the binary oxide CuO can become a room-temperature multiferroic via tuning of the superexchange interactions by application of pressure. Thus far, however, there has been no experimental evidence for the predicted room-temperature multiferroicity. Here, we show by neutron diffraction that the multiferroic phase in CuO reaches 295 K with the application of 18.5 GPa pressure. We also develop a spin Hamiltonian based on density functional theory and employing superexchange theory for the magnetic interactions, which can reproduce the experimental results. The present Letter provides a stimulus to develop room-temperature multiferroic materials by alternative methods based on existing low temperature compounds, such as epitaxial strain, for tunable multifunctional devices and memory applications.

We reveal the microscopic origin of electric polarization $\vec{P}$ induced by noncollinear magnetic order. We show that in Mott insulators, such $\vec{P}$ is given by all possible combinations of position operators $\hat{\vec{r}}_{ij} = (\vec{r}_{ij}^{\, 0},\vec{\boldsymbol{r}}_{ij}^{\phantom{0}})$ and transfer integrals $\hat{t}_{ij} = (t_{ij}^{0},\boldsymbol{t}_{ij}^{\phantom{0}})$ in the bonds, where $\vec{r}_{ij}^{\, 0}$ and $t_{ij}^{0}$ are spin-independent contributions in the basis of Kramers doublet states, while $\vec{\boldsymbol{r}}_{ij}^{\phantom{0}}$ and $\boldsymbol{t}_{ij}^{\phantom{0}}$ stem solely from the spin-orbit interaction. Among them, the combination $t_{ij}^{0} \vec{\boldsymbol{r}}_{ij}^{\phantom{0}}$, which couples to the spin current, remains finite in the centrosymmetric bonds, thus yielding finite $\vec{P}$ in the case of noncollinear arrangement of spins. The form of the magnetoelectric coupling, which is controlled by $\vec{\boldsymbol{r}}_{ij}^{\phantom{0}}$, appears to be rich and is not limited to the phenomenological law $\vec{P} \sim \boldsymbol{\epsilon}_{ij} \times [\boldsymbol{e}_{i} \times \boldsymbol{e}_{j}]$ with $\boldsymbol{\epsilon}_{ij}$ being the bond vector connecting the spins $\boldsymbol{e}_{i}$ and $\boldsymbol{e}_{j}$. Using density-functional theory, we illustrate how the proposed mechanism work in the spiral magnets CuCl$_2$, CuBr$_2$, CuO, and $\alpha$-Li$_2$IrO$_3$, providing consistent explanation to available experimental data., Comment: 6 pages, 3 figures

The layered two-dimensional material ${\mathrm{MoTe}}_{2}$ in the ${T}_{d}$ crystal phase is a semimetal which has theoretically been predicted to possess topologically nontrivial bands corresponding to Weyl fermions. Clear experimental evidence by angle-resolved photoemission spectroscopy (ARPES) is, however, lacking, which calls for a careful examination of the relation between ground state band structure calculations and ARPES intensity plots. Here we report a study of the near-Fermi-energy band structure of ${\mathrm{MoTe}}_{2}({T}_{d})$ by means of ARPES measurements, density functional theory, and one-step-model ARPES calculations. Good agreement between theory and experiment is obtained. We analyze the orbital character of the surface bands and its relation to the ARPES polarization dependence. We find that light polarization has a major effect on which bands can be observed by ARPES. For $s$-polarized light, the ARPES intensity is dominated by subsurface Mo $d$ orbitals, while $p$-polarized light reveals the bands mainly derived from Te $p$ orbitals. Suitable light polarization for observing either an electron or hole pocket are determined.

As is well known, the single-site anisotropy vanishes in the spin-$\frac{1}{2}$ compounds as a consequence of the fundamental Kramers degeneracy. We argue, rather generally, that a similar property holds for the magnetically induced electric polarization $\mathbit{P}$, which should depend only on the relative orientation of spins in the bonds but not on the direction of each individual spin. Thus, for insulating multiferroic compounds, $\mathbit{P}$ can be decomposed in terms of pairwise isotropic, antisymmetric, and anisotropic symmetric contributions, which can be rigorously derived in the framework of the superexchange (SE) theory, in analogy with the spin Hamiltonian. The SE theory also allows us to identify the microscopic mechanism that stands behind each contribution. The most controversial and intriguing one---concerning the form, appearances, and implications for the properties of real compounds---is the antisymmetric or spin-current mechanism. In this work, we propose that, within the SE theory, the disputed magnetoelectric (ME) properties of tetragonal ${\mathrm{Ba}}_{2}\mathrm{Cu}{\mathrm{Ge}}_{2}{\mathrm{O}}_{7}$, representing the lattice of magnetic ${\mathrm{Cu}}^{2+}$ ions in the tetrahedral environment, can be explained solely by the spin-current mechanism, while other contributions are either small or forbidden by symmetry. First, after analysis of the symmetry properties of the SE Hamiltonian and corresponding parameters of electric polarization, we explicitly show how the cycloidal spin order induces the experimentally observed electric polarization in the direction perpendicular to the tetragonal plane, which can be naturally explained by the spin-current mechanism operating in the out-of-plane bonds. Then, we unveil the previously overlooked ME effect, where the application of the magnetic field perpendicular to the plane not only causes the incommensurate-commensurate transition, but also flips the electric polarization into the plane due to the spin-current mechanism operating in the neighboring bonds within this plane. In both cases, the magnitude and direction of $\mathbit{P}$ can be controlled by rotating the spin pattern in the tetragonal plane. Our analysis is based on a realistic spin model, which was rigorously derived from first-principles electronic structure calculations and supplemented with a new algorithm for the construction of localized Wannier functions obeying the crystallographic symmetry of ${\mathrm{Ba}}_{2}\mathrm{Cu}{\mathrm{Ge}}_{2}{\mathrm{O}}_{7}$.

This article describes my teaching of futures to experts in public services such as water supply, power supply, and waste treatment in developing countries. These experts come to Japan to participate in the training course of their field of service, which is offered by a state-run organization in Japan. At the end of the course, they prepare an action plan, which is to be implemented after they return to their countries. In the course, I give them three lectures on futures to help them make their action plans more future-oriented. Experts are quite different from university students in that they carry the burden and responsibility to make services better and more effective in the future. Most of them assume, in their planning, that data and information in the past and present form the foundation on which they project the future of their services. As a result, their plans are always based on a probable future and not on possible futures. I teach them futures to point out the risks of such planning approach, and to open their eyes to an alternative one, which I call “Futures planning.” By following the three lectures in chronological order, this article clarifies characteristics of my futures teaching and its impact on the experts from developing countries.

This paper proposes a continuous identification scheme monitoring a driver's behavior and a detection scheme for an impostor. The proposed scheme uses Long Short-Term Memory (LSTM) to create a classifier of the driver's behavior according to acceleration data and classifies a driver. Additionally, it also detects an impostor according to statistical information of output from the classifier. Experimental results show that an acceleration sensor on a real vehicle is enough to classify 15 drivers according to real-time driver's behavior. Additionally, the proposed scheme can detect an impostor through the verification of real experimental data.

We previously proposed a basket-forceps-type flow sensor, in which a flexible thermal flow sensor is mounted onto basket forceps to fix the flow sensor onto the inside surface of the airway. The basket-forceps-type flow sensor has an asymmetrical structure to prevent reciprocating airflow; thus, we investigated the characteristics of the basket-forceps-type flow sensor under both expired- and inspired-airflow conditions in this study. The thermal flow sensor was fabricated on a flexible polyimide film and mounted onto a guide tube of a basket-forceps. Two heaters and their electrical wiring patterns were designed to produce symmetric heat distribution over the heaters. The effects of the basket structure and guide tube on flow-rate measurement were experimentally evaluated, and it was confirmed that they did not affect sensor output. Conversely, sensor output decreased with the increase in tube diameter due to the reduction in the average flow velocity with the diameter increase. Thus, we carried out a procedure to construct a calibration curve under an arbitrary tube diameter. Finally, we applied the basket-forceps-type flow sensor in an animal experiment in which it successfully detected the breathing properties in the airway of a rat.

We developed a basket forceps with a flow sensor for evaluating the breathing characteristics in small airways. The flow sensor, fabricated using mirco-eletro-mechanical systems technologies, was integrated into a guide wire with the basket forceps. The fundamental sensor characteristics, response time and flow rate vs. sensor output curve, were experimentally confirmed. The sensor was successfully fixed to the inside surface of a small tube by using the bending arms of the basket forceps. We confirmed that the breathing properties of a rat were successfully detected with the integrated flow sensor.

An image of the future that an individual holds determines what attitude he/she holds towards the future and how he/she behaves in the present. These in turn would increase the probability to make the image realized as imagined in the future. As young people will be the builders of a society in the future, investigating their images of the future has significant implications for the future. With a survey of two groups of university students in Taiwan and the U.S., this study looked into various aspects of images, explored message sources influencing the formation of the images, identified values embedded in the images, and explored the relationship between the images and the students’ understanding of the present.

In The Future Internet: Alternative Visions, a diverse group of futures researchers explore alternative visions of the future Internet, highlighting key uncertainties that are not well addressed in the current discourse about technology and policy developments. Corporate, academic, and policy visions associated with the future Internet present a techno-utopian view, focusing on the integration of myriad computational objects into the everyday environment in order to enable economic growth, strengthen security, enhance business and government efficiency, and promote environmental sustainability and personal convenience. Contributors to this volume probed the underlying values, beliefs, and thinking that are influencing those futures, and presented a compelling array of alternative visions about the future Internet. In this concluding chapter, we perform a macroanalysis of the scenarios presented in the preceding chapters from predictive, cultural, and critical futures studies perspectives and discuss the role of futures studies and images of the future as a means to help stakeholders make truly “better” decisions about the future of the Internet.

Many of the visions that shape the Internet’s development and use are driven by research institutions, corporations, and governments, enabling consensus about research and policy problems. While there is not a single vision of the future Internet, there are a number of overlapping, and influential, visions shared between academic and corporate researchers and governments. These all point towards the embedding of computational intelligence into many aspects of everyday life and the growth of technical standards enabling machine-to-machine (M2M) intelligence. The first part of this chapter introduces the dominant techno-utopian vision of the future Internet. Then, the field of futures studies is introduced as a means to perform systematic thinking about alternative futures. Finally, we introduce the individual chapters in this volume.

Forecasting is an essential factor in policy formulation and planning. It helps determine the direction of future actions. While a number of forecasting techniques are utilized to forecast the future, it is important to know just how valid those forecasting techniques can be. The Delphi technique has been called the ‘cornerstone of futures research’. This study reports the results of the assessment of the accuracy of the forecasts derived from the Delphi technique. Twenty-five experts in the communication field assessed 24 trends and 17 events in the state of Hawaii as of 1991. The expert assessments were then compared with the forecasts made by utilizing the Delphi technique 16 years earlier. The results showed that the trend forecasts were significantly correlated with the trend assessment. They also showed that the Delphi technique had accurately forecast approximately half the events that could be evaluated as of 1991. Results from this study lend support to the use of the Delphi technique in long-range forecasting and reveal some interesting findings in forecasting the developments in communication in Hawaii.

The stable development of telecommunications in the developing countries has been hindered by a variety of difficulties. Development assistance by the developed countries and a number of organizations has an important role in helping the developing countries overcome these difficulties and promote their telecommunications development. This paper examines different kinds of development assistance and suggests that the role of the ITU will be crucial to any improvement in coordination of assistance.