One-dimensional electronic systems: metal-chain complexes and organic conductors

This article is part of the themed collection: Functional Coordination NetworksOne-dimensional (1D) metal-chain complexes and organic conductors show many similarities as well as striking differences in structural and electronic properties, although constituent elements and orbitals that contribute to charge transfer in these systems are quite different. In this review, we highlighted the structural and electronic properties of neutral MMX-chain complexes (M = Pt²⁺/³⁺, X = I⁻) and tetramethyltetrathiafulvalene-based cation radical salts as typical examples of each group while comparing them with each other. This review primarily aims to construct a coherent body of knowledge of 1D electronic materials that might have been separately investigated. We have proposed future directions for the exploration of new and more advanced electronic materials not only having 1D character, but also residing in the dimensional crossover regime

Roll in/out and Usage of Large Capacity Core Memory in a Time-sharing System

In this paper the analysis of roll in/out operation and the usage of large capacity core memory (LCM) in a time-sharing system (TSS) are described. A TSS model based on a few assumptions is proposed, and the relation between roll in/out and system performance is analyzed. The system is classified into two types, i.e. swapping limited and CPU limited, according to whether the maximum system performance is restricted by capability of swapping devices or central processing units, and using LCM in TSS is very effective for the swapping limited case because of decrease of system overhead due to roll in/out operation and increase of system performance. The usage of LCM is divided into two main classes, i.e. as roll-out area and roll-in area, and a system model with LCM is analyzed and discussed in each class. One of the typical cases of using LCM as roll-in area is the implementation of conversational language in interpretive mode, then, the condition on which the interpreter program using LCM is operated in swapping limited state in spite of decrease of swapping overhead and increase of CPU time is obtained, and a numerical example is showed. Finally, an optimum algorithm for the use of LCM, which betters system performance in man-computer communication, is suggested

Legibility of Japanese characters in graphic floor signs for elderly people

For low-vision people and elderly people with decreased vision and cognitive function, the legibility of signs (character size, position, etc.) is an important issue. Graphic floor signs are considered more effective for low-vision people and elderly people than typical hanging signs because they are closer to pedestrians and can be larger in size. There is a growing number of improved graphic floor signs, but there are no guidelines for character sizes, colour scheme, and layout. Therefore, this study considers the character size ofgraphic floor signs that are legible for elderly people. In this study, we aimed to verify the legibility of characters installed on the floor. The test was conducted on 30 non-elderly and 30 elderly people, about Japanese Industrial Standards (JIS) S 0032 “Guidelines for the elderly and people with disabilities - Visual signs and displays -Estimation of minimum legible size for a Japanese single character”. Experiments on minimum legible sizes of characters and experiments on readability were conducted in that order. In the experiment on the minimum legible sizes of characters, we found that the minimum legible sizes of characters written on the vertical surface can be converted to the minimum size of legible characters written on the floor surface by multiplying with the coefficient of minimum legible characters on the floor surface by 2 to 3 times. In the experiment on readability, we found that the optimum character sizes are about 90 mm and 80 mm in height at a minimum for vertical and horizontal characters, respectively. These results showed that the optimum size of characters on graphic floor signs is about 90 mm.Peer Reviewe

Highly sensitive chiral analysis in capillary electrophoresis with large-volume sample stacking with an electroosmotic flow pump.

To improve the sensitivity in chiral analysis by capillary electrophoresis without loss of optical resolution, application of large-volume sample stacking with an electroosmotic flow pump (LVSEP) was investigated. Effects of the addition of cyclodextrin (CD) into a running solution on the LVSEP preconcentration was theoretically studied, where the preconcentration efficiency and effective separation length would be slightly increased if the effective electrophoretic velocity (v(ep, eff, BGS)) of the analytes was decreased by interacting with CD. In LVSEP-CD-modified capillary zone electrophoresis (CDCZE) and LVSEP-CD electrokinetic chromatography with reduced v(ep, eff, BGS), up to 1000-fold sensitivity increases were achieved with almost no loss of resolution. In LVSEP-CD-modified micellar electrokinetic chromatography of amino acids with increased v(ep, eff, BGS), a 1300-fold sensitivity increase was achieved without much loss of resolution, indicating the versatile applicability of LVSEP to many separation modes. An enantio-excess (EE) assay was also carried out in LVSEP-CDCZE, resulting in successful analyses of up to 99.6% EE. Finally, we analyzed ibuprofen in urine by desalting with a C(18) solid-phase extraction column. As a typical result, 250ppb ibuprofen was well concentrated and optically resolved with 84.0-86.6% recovery in LVSEP-CDCZE, indicating the applicability of LVSEP to real samples containing a large amount of unnecessary background salts

A Preinstalled Protic Cation as a Switch for Superprotonic Conduction in a Metal–Organic Framework

Metal–organic frameworks (MOFs), made from various metal nodes and organic linkers, provide diverse research platforms for proton conduction. Here, we report on the superprotonic conduction of a Pt dimer based MOF, [Pt₂(MPC)₄Cl₂Co(DMA)(HDMA)·guest] (H₂MPC, 6-mercaptopyridine-3-carboxylic acid; DMA, dimethylamine). In this framework, a protic dimethylammonium cation (HDMA⁺) is trapped inside a pore through hydrogen bonding with an MPC ligand. Proton conductivity and X-ray measurements revealed that trapped HDMA⁺ works as a preinstalled switch, where HDMA⁺ changes its relative position and forms an effective proton-conducting pathway upon hydration, resulting in more than 105 times higher proton conductivity in comparison to that of the dehydrated form. Moreover, the anisotropy of single-crystal proton conductivity reveals the proton-conducting direction within the crystal. The present results offer insights into functional materials having a strong coupling of molecular dynamic motion and transport properties

Enhancing Hydrogen Storage Capacity of Pd Nanoparticles by Sandwiching between Inorganic Nanosheets

H₂ is regarded to play a crucial role in the transition from a fossil fuel-based energy economy towards an environmentally friendly one. However, storage of H₂ is still challenging, but palladium (Pd) based materials show exciting properties. Therefore, nanoparticulate Pd has been intensely studied for hydrogen storage in the past years. Here, we stabilize Pd nanoparticles by intercalation between inorganic nanosheets of hectorite (NaHec). Compared to nanoparticles stabilized by the polymer polyvinylpyrrolidone (PVP), the H₂ storage capacity was found to be 86 % higher for identical Pd nanoparticles being intercalated between nanosheets. We attribute this remarkably enhanced H₂ storage capacity to the partial oxidation of Pd, as evidenced by X-ray photoelectron spectroscopy (XPS). The higher amount of holes in the 4d band leads to a higher amount of H₂ that can be absorbed when Pd is stabilized between the nanosheets of hectorite compared to the PVP stabilized nanoparticles