Junya Uchida

Functional Liquid Crystals towards the Next Generation of Materials

Since the discovery of the liquid-crystalline state in 1888, liquid crystal science has made great advances through fusion with various technologies and disciplines. Recently, new molecular design strategies and new self-assembled structures have been developed as a result of the progress made in synthetic procedures and characterization techniques. Since these liquid crystals exhibit new functions and properties derived from their nanostructures and alignment, a variety of new functions for liquid crystals, such as transport for energy applications, separation for environmental applications, chromism, sensing, electrooptical effects, actuation, and templating have been proposed. This Review presents recent advances of liquid crystals that should contribute to the next generation of materials.

Model depiction of the atmospheric flows of radioactive cesium emitted from the Fukushima Daiichi Nuclear Power Station accident

In this study, a new method is proposed for the depiction of the atmospheric transportation of the 137Cs emitted from the Fukushima Daiichi Nuclear Power Station accident. This method employs a combination of the results of two aerosol model ensembles and the hourly observed atmospheric 137Cs concentration at surface level during 14–23 March 2011 at 90 sites in the suspended particulate matter monitoring network. The new method elucidates accurate transport routes and the distribution of the surface-level atmospheric 137Cs relevant to eight plume events that were previously identified. The model ensemble simulates the main features of the observed distribution of surface-level atmospheric 137Cs. However, significant differences were found in some cases, and this suggests the need to improve the modeling of the emission scenario, plume height, wet deposition process, and plume propagation in the Abukuma Mountain region. The contributions of these error sources differ in the early and dissipating phases of each event, depending on the meteorological conditions.

Liquid-crystalline fork-like dendrons

ABSTRACT Dendritic molecules having several rigid-rod moieties can be applied to induce liquid crystallinity for a variety of non-mesomorphic functional molecules such as metal complexes, nanoparticles, fullerenes and π-conjugated molecules when these dendritic molecules are covalently bonded to those non-mesomorphic molecules. These complex molecules are called supermolecular liquid crystals. Due to the cooperation of several mesogenic moieties, these dendritic molecules exhibit very stable liquid-crystalline (LC) phases. We have used fork-shaped LC dendrons having two or three rigid-rod moieties to induce liquid crystallinity for functional molecules such as interlocked molecules and π-conjugated molecules. In these fork-like molecules, the rigid-rod cores are attached to the 3,4,5-position of the phenyl moieties through flexible spacer, and these molecules are bonded to functional molecules through the 1-position. They basically form smectic LC phases, which induce the layered arrangement of functional moieties. Here we report on a new family of fork-like mesogens containing a hydrogen bonding moiety or an ionic group. They are designed to build supramolecular materials. GRAPHICAL ABSTRACT

Error and Energy Budget Analysis of a Nonhydrostatic Stretched-Grid Global Atmospheric Model

AbstractA nonhydrostatic stretched-grid (SG) model is used to analyze the large-scale errors generated by stretching horizontal grids and their influence on a region of interest. Simulations by a fully compressible, nonhydrostatic global atmospheric model, the Nonhydrostatic Icosahedral Atmospheric Model (NICAM), and its SG regional model, stretched-NICAM, were performed for the months of March, April, and May of 2011 using various resolutions and stretching factors. A comparison of week-long accumulative precipitation amounts between the Tropical Rainfall Measuring Mission (TRMM) satellite data and the quasi-uniform and SG simulations showed that a stretched run better represents storms and associated precipitation because the errors generated in the outer regions with coarser grid spacing do not significantly affect the inner domain centered at the focal point. For season-long simulations, in one particular set of stretched runs with the focal point located in the eastern United States, the artificial s...

Self‐Assembly of Giant Spherical Liquid‐Crystalline Complexes and Formation of Nanostructured Dynamic Gels that Exhibit Self‐Healing Properties

Supramolecular self-assembly of 24 forklike mesogenic ligands and 12 transition metal ions led to the formation of giant spherical coordination complexes that exhibit liquid-crystalline (LC) phases. Self-healing LC supramolecular gels were also obtained through the introduction of these LC nanostructured supramolecular giant spherical complexes into dynamic covalent networks formed by cross-linkers and bifunctional polymers. The giant spherical structures of the PdII complexes with 72 rodlike moieties on the periphery were characterized by NMR, diffusion-ordered NMR spectroscopy, and mass spectrometry. These complexes are stable and exhibit lyotropic LC behavior, while the mesogenic ligands show thermotropic LC properties. The self-assembled LC structures of the spherical complexes can be tuned by the length of the rodlike moieties.

Multi-scale Simulations of Atmospheric Pollutants Using a Non-hydrostatic Icosahedral Atmospheric Model

We have developed a seamless global-to-regional model to calculate atmospheric aerosol chemistry by coupling existing aerosol and chemical modules to a global cloud-system-resolving model (NICAM-Chem). The model can simulate air pollutants with various grid sizes ranging from global low resolution (~200 km) on yearly scales to regional high resolution (~10 km) on monthly scales and global high resolution (<10 km) on weekly scales. To date, we have confirmed that the NICAM-Chem simulated aerosols at low-to-high resolutions, and global-to-regional scales are generally comparable to validated observations. Furthermore, the very recent availability of cutting-edge computational capabilities provided by the K computer at RIKEN in Japan enabled us to perform seasonal air pollution simulations with a high global resolution model (14 km), which generally reproduced the observed aerosol distributions. In this paper, we introduce the following application studies using the NICAM-Chem model: future scenario experiments, downscaling using results obtained by a coupled atmosphere-ocean model, estimation of human health due to PM2.5, simulations of radioactive matter using a regional model, and aerosol assimilation by a localized ensemble transform Kalman filter.