Microstructure Development and Dielectric Properties of Potassium Strontium Niobate Ceramics

Sintering of a KSr₂Nb₅O₁₅ powder compact at 1350°C resulted in a duplex structure. Prefiring of the compact between 1200° and 1300°C inhibited the abnormal grain growth responsible for the duplex structure. The Curie temperature and dielectric constant were dependent on the microstructure.     

Ceramic Dental Molds for the Precision Casting of Titanium and Titanium Alloys: I, Relationship between Particle-Size Distribution of Aggregates and Mold Expansion

A new ceramic dental mold can cast excellent Ti restoratives by controlling expansion due to the oxidation of additive metal particles. The packing structure of the metal and aggregate particles in the mold can be considered a function of the size distribution of the aggregate grains. An investigation of the expansion mechanism reveals three different relationships of void fraction versus linear thermal expansion for the molds at the high temperature under which oxidation of the metal particles occurs. Room-temperature casting, favorable for making high-quality Ti restoratives, can also be achieved by precisely controlling both the amount of additive metal powder and the compositional distribution of aggregate grain sizes in the mold.     

Time division multiplexed OTDR system

A new technique to increase the effective sampling rate of an optical time-domain reflectometer using a time division multiplexing digital sampling averaging procedure is proposed. This permits an increase in distance measuring accuracy of an optical time-domain reflectometer.     

Degradation of Pentoses and Hexouronic Acids in Subcritical Water

The degradation of arabinose, xylose, ribose and lyxose in subcritical water was measured at 200, 220 and 240 °C. Ribose was the most rapidly degraded among the pentoses tested. The degradation of the glucuronic and galacturonic acids proceeded at lower temperatures than that of the pentoses, and was measured at 140, 150 and 160 °C. The degradation processes of the pentoses and hexouronic acids could be expressed by the Weibull model, and the kinetic parameters were then estimated. The activation energy and frequency factor for the degradation of each substrate were estimated from the temperature dependence of the rate constant. The enthalpy‐entropy compensation held for the degradation of the pentoses as well as the hexoses, which suggests that the degradation of the hexouronic acids proceeded through a mechanism different from that for the pentoses and hexoses. The molar yield of a pentose to furfural was ca. 0.3 at any temperature, irrespective of the pentose type. Acidic compounds were also formed from the pentoses in proportion to the amount of consumed substrates. The formation of acidic compounds resulted in a rapid decrease in pH.     

Ductility and toughness in intermetallics

Limited ductility and toughness at low temperatures are serious disadvantages in intermetallics. As in other metallic materials, the two major brittle failure modes in intermetallics are cleavage and intergranular fracture. We focus on cleavage fracture and the corresponding brittle-to-ductile transition mechanism. To prevent cracking, a ‘sufficient number’ of dislocations must be generated at a crack tip, and this ‘sufficient number’ appears to be very large. This event is more like a phase transition than an ordinary thermally activated process. In this paper a new theoretical model, proposed to explain the BDT is summarized. The micro-structural implications of this model are presented and the means of achieving an acceptable combination of strength and toughness through microstructural control are then discussed, along with examples.     

Formation of AI-Cr-Si quasicrystal with high silicon concentration by rapid quenching and its thermal and electrical properties

A quasicrystal revealing five-fold symmetry has been found to be formed in a rapidly quenched Al₆₂Cr₁₉Si₁₉ alloy containing a large amount of metalloid silicon. From analysis by the TEM/EDX method, the quasicrystalline single phase was determined to have a composition of Al_62.5Cr_17.6Si_19.9. The quasicrystal is composed of randomly-oriented equiaxed grains with an average size of 0.5 μm. The quasicrystal transforms to a stable Al₁₃Cr₄Si₄ compound with a complex cubic structure in the temperature range of 710 to 800 K. The activation energy and heat for the transformation are 85 kJ mol^?1 and 2.57 kJ mol^?1, respectively. The electrical resistivities (?) at 4.2 and 250 K are 2.83 and 3.65 μ?m, respectively, and its temperature coefficient at 250 K is 9.33 × 10^?4K^?1. The formation of the quasicrystal in the vicinity of Ai₁₃Cr₄Si₄ was inferred to be due to the combination effect of a great supercooling ability caused by the low melting temperature for AI-Si and Cr-Si eutectic type alloys and the difficulty of diffusivity of the constituent atoms in the ternary compound with a large unit cell and a strong bonding nature between chromium and aluminium or silicon.     

Supramolecular Ligands for Histone Tails by Employing a Multivalent Display of Trisulfonated Calix[4]arenes

Post‐translational modification of histone tails plays critical roles in gene regulation. Thus, molecules recognizing histone tails and controlling their epigenetic modification are desirable as biochemical tools to elucidate regulatory mechanisms. There are, however, only a few synthetic ligands that bind to histone tails with substantial affinity. We report CA2 and CA3, which exhibited sub‐micromolar affinity to histone tails (especially tails with a trimethylated lysine). Multivalent display of trisulfonated calix[4]arene was important for strong binding. CA2 was applicable not only to synthetic tail peptides but also to endogenous histone proteins, and was successfully used to pull‐down endogenous histones from nuclear extract. These findings indicate the utility of these supramolecular ligands as biochemical tools for studying chromatin regulator protein and as a targeting motif in ligand‐directed catalysis to control epigenetic modifications.     

Real‐time histological imaging of kidneys stained with food dyes using multiphoton microscopy

We have developed a real‐time imaging technique for diagnosis of kidney diseases which is composed of two steps, staining renal cells safely with food dyes and optical sectioning of living renal tissue to obtain histological images by multiphoton microscopy (MPM). Here, we demonstrated that the MPM imaging with food dyes, including erythrosine and indigo carmine, could be used as fluorescent agents to visualize renal functions and structures such as glomerular bloodstreams, glomerular filtration, and morphology of glomeruli and renal tubules. We also showed that the kidneys of IgA nephropathy model‐mice stained with the food dyes presented histopathological characteristics different from those observed in normal kidneys. The use of the food dyes enhances the quality of tissue images obtained by MPM and offers the potential to contribute to a clinical real‐time diagnosis of kidney diseases. Microsc. Res. Tech. 78:847–858, 2015. © 2015 Wiley Periodicals, Inc.     

Molybdenum‐Catalyzed Stereospecific Deoxygenation of Epoxides to Alkenes

Mild and simple catalytic systems consisting of molybdenum(VI) dichloride dioxide [MoO₂Cl₂] as a catalyst and a phosphine as reductant have been developed for the stereospecific deoxygenation of epoxides to alkenes. The reactions using 1,2‐bis(diphenylphosphino)ethane (dppe) and triphenylphosphine (PPh₃) proceed with retention and inversion of stereochemistry, respectively. The mild reaction tolerates the presence of various functional groups and affords stereodefined substituted olefins in good yields.

     

可持续发展实验住宅——日本积水住宅公司实验住宅案例介绍

可持续发展实验住宅是在东京城市住宅区中建设的一栋有研究性质的实验住宅,其宗旨是要通过充分利用风、阳光等自然的力量来实现不依赖于机械设备的节能而且舒适的生活.借鉴传统日本住宅的优点,创造重视居住者心理感受的生活环境,并通过居住实验证实了该住宅可以让居住者感受到比客观测定的物理环境值更具舒适性的居住品质.