Photoswitching of electron transfer property of diarylethene–viologen linked molecular layer constructed on a hydrogen-terminated Si(111) Surface

An organic monolayer with diarylethene and viologen moieties as a photochromic and an electroactive group, respectively, was constructed on a hydrogen-terminated Si(111) surface by sequential surface reactions. Photoswitching behaviour of electron transfer from the Si electrode to viologen moiety, larger and smaller current after UV and visible irradiation, respectively, was observed. This photoswitching behaviour can be explained by a change in molecular conductivity of diarylethene moiety, which separates Si surface and viologen moiety, as a result of ring closing and opening induced by UV and visible irradiation, respectively.     

Performance decay of proton-exchange membrane fuel cells under open circuit conditions induced by membrane decomposition

The degradation in performance of proton-exchange membrane fuel cells (PEMFCs) under open circuit conditions was investigated. The oxygen reduction reaction (ORR) kinetic current density at 0.9 V was found to decrease from 36 to 4 mA cm⁻² (geometric) without significant crossover increase or loss in the electrochemically active surface area. Cyclic voltammograms for the electrodes show characteristic changes, e.g. appearance of peaks at ∼0.2 V and shift of the onset of platinum oxide formation to higher potentials. It was identified that the large ORR kinetic decay has its origins in the reduction of available Pt sites due to adsorption of anions, which are postulated to be membrane decomposition products such as sulfate ions. Procedures carried out to condense water in the fuel cell led to the expulsion of anions out of the membrane electrode assembly (MEA) resulting in the partial recovery of ORR kinetic current density to 15 mA cm⁻². In order to attain complete performance recovery of the catalyst, a more effective and practical method to flush out the anions is desirable.     

Relationship between electron sensitivity and chemical structures of polymers as electron beam resists. VI: Electron sensitivity of various acetalized poly(vinyl alcohol)s

Acetalized poly(vinyl alcohol)s which were synthesized from poly(vinyl alcohol) (PVA) and aldehyde or ketone were evaluated as electron beam (EB) resists, in order to investigate the relationship between EB sensitivity and chemical structures of the polymers. It was found that the acetalized PVAs were easily crosslinked by EB exposure. The main mechanism of crosslinking may be radical reaction at acetal group. The sensitivity of the acetalized PVA depended on the structure of the acetal group. Acetalized PVAs synthesized from benzaldehyde, in which the electron attracting group was substituted on the benzene ring and from linear aliphatic aldehyde having a long alkyl chain, had high sensitivity. A high sensitivity of 7.2 × 10⁻⁷ C/cm² was attained when the acetalized PVA synthesized from p-chloro-benzaldehyde was used. Acetalized PVAs synthesized from PVA and aldehyde having a cyclic structure had an excellent dry etching durability and were suitable as negative EB resists.     

Unexpected Pleiotropic Effects of SGLT2 Inhibitors: Pearls and Pitfalls of This Novel Antidiabetic Class

Sodium-glucose co-transporter 2 (SGLT2) inhibitors facilitate urine glucose excretion by reducing glucose reabsorption, leading to ameliorate glycemic control. While the main characteristics of type 2 diabetes mellitus are insufficient insulin secretion and insulin resistance, SGLT2 inhibitors have some favorable effects on pancreatic β-cell function and insulin sensitivity. SGLT2 inhibitors ameliorate fatty liver and reduce visceral fat mass. Furthermore, it has been noted that SGLT2 inhibitors have cardio-protective and renal protective effects in addition to their glucose-lowering effect. In addition, several kinds of SGLT2 inhibitors are used in patients with type 1 diabetes mellitus as an adjuvant therapy to insulin. Taken together, SGLT2 inhibitors have amazing multifaceted effects that are far beyond prediction like some emerging magical medicine. Thereby, SGLT2 inhibitors are very promising as relatively new anti-diabetic drugs and are being paid attention in various aspects. It is noted, however, that SGLT2 inhibitors have several side effects such as urinary tract infection or genital infection. In addition, we should bear in mind the possibility of diabetic ketoacidosis, especially when we use SGLT2 inhibitors in patients with poor insulin secretory capacity.     

Robust topology optimization of multi-material lattice structures under material and load uncertainties

Frontiers of Mechanical Engineering - Enabled by advancements in multi-material additive manufacturing, lightweight lattice structures consisting of networks of periodic unit cells have gained...     

THE CHARACTERISTIC EFFECTS OF VARIOUS IRON SULFIDE CATALYSTS IN COAL LIQUEFACTION

In order to investigate the effective mechanism of pyrite catalyst, coal liquefaction was conducted using a 500 ml autoclave. When the chemical structure characteristics of products and product yields are considered as a whole, deoxygenation and dealkylation are found to be enhanced in the presence of pyrite catalyst. Further, it is surmised that depolymerization is faster than the removal of heteroatoms.     

Experimental study on effect of elasticity on drag reduction and turbulent fluctuations in laminar-turbulent transition region in pipe flow of dilute polymer solutions

By utilizing the fact that physical properties exclusive of elasticity of dilute polyacrylamide solutions do not change with elapsed time after preparation, the effect of elasticity on drag reduction and turbulent fluctuations in pipe flow was investigated experimentally. The oscillations of axial velocity and velocity gradient and the drag reduction in the laminar-turbulent transition region are affected significantly by the value of elasticity. The laminar-turbulent transition region moves to a higher Reynolds number as the value of elasticity increases.     

Relationship between electron sensitivity and chemical structures of polymers as electron beam (EB) resists. V: Polyamides containing sulfur groups as positive eb resists

Polyamidethioethers were synthesized and evaluated as positive electron beam (EB) resists, The polyamidethioethers decomposed easily with EB exposure. At high doses (indicating low sensitivity), crosslinking reactions occurred for polyamidethioethers having C-S bonds produced by Michael addition, but the other polyamidethioethers did not crosslink. The C-S bonds produced by Michael addition may influence crosslinking rather than decomposition. The sensitivity of oxidized polyamidethioether was higher than that of the nonoxidized polymer with no change in resolution. The oxidized polyamidethioether had a high sensitivity and a high resolution, and is adaptable as a positive EB resist.     

Oblique Promax Rotation Applied to the Solutions in Multiple Correspondence Analysis

There are many approaches to formulate multiple correspondence analysis of multi-item categorical data. A lower-rank approximation approach gives the freedom for the oblique rotation of axes. In the current paper, we apply the oblique rotation of axes to a variable-by-dimension matrix to arrive at simple structure. This matrix is defined in either of two different manners, that is, by treating categories as variables or, alternatively, by treating items as variables. For each of these two options, the standardized inner products between dimensions and variables are used as the elements of the component structure matrix. We adopt a promax method for the oblique rotation. In this method, scores are rotated in such a way that the above matrix is matched with the target matrix obtained from the result of the varimax rotation.

     

The BC-chain method for representing combinators in linear space

Turner’s combinator implementation (1979) of functional programs requires the memory space of size Ω(n ²) in the worst case for translating given lambda expressions of lengthn to combinator graphs. In this paper a new idea named the BC-chain method for transferring actual arguments to variables is presented. We show that the BC-chain method requires onlyO(n) space for the translation. The basic idea is to group together into a single entity a sequence of combinatorsB, B′, C andC′, for a variable, which appear consecutively along a path in the combinator graph. We formulate two reduction algorithms in the new representation. The first algorithm naively simulates the original normal order reduction, while the second algorithm simulates it in constant time per unit operation of the original reduction. Another reduction method is also suggested, and a technique for practical implementation is briefly mentioned.