Disparities of indoor temperature in winter: A cross-sectional analysis of the Nationwide Smart Wellness Housing Survey in Japan

The WHO Housing and health guidelines recommend a minimum indoor temperature of 18°C to prevent cold-related diseases. In Japan, indoor temperatures appear lower than in Euro-American countries because of low insulation standards and use of partial intermittent heating. This study investigated the actual status of indoor temperatures in Japan and the common characteristics of residents who live in cold homes. We conducted a nationwide real-world survey on indoor temperature for 2 weeks in winter. Cross-sectional analyses involving 2190 houses showed that average living room, changing room, and bedroom temperatures were 16.8°C, 13.0°C, and 12.8°C, respectively. Comparison of average living room temperature between prefectures revealed a maximum difference of 6.7°C (Hokkaido: 19.8°C, Kagawa: 13.1°C). Compared to the high-income group, the odds ratio for living room temperature falling below 18°C was 1.38 (95% CI: 1.04-1.84) and 2.07 (95% CI: 1.28-3.33) for the middle- and low-income groups. The odds ratio was 1.96 (95% CI: 1.19-3.22) for single-person households, compared to households living with housemates. Furthermore, lower room temperature was correlated with local heating device use and a larger amount of clothes. These results will be useful in the development of prevention strategies for residents who live in cold homes.     

Inorganic Design of Protein Assemblies as Supramolecular Platforms

In the last decade, there has been great deal of progress in the study of self-assembly processes of protein assemblies as biotemplates to create and construct one-dimensional arrays of nanocrystalline metals and semiconductors. Successful attempts in fabricating the protein-based bioelectronics could serve as a promising alternative to synthetic template based nanomaterials. Another perspective of protein assemblies is its use in the field of tissue engineering either as scaffold for cell adhesion and proliferation or as a foreign (bio)nanofunctionality to communicate with the macromolecules present in the extracellular or intracellular milieu and participate in the precise control of vital cell functions. Three-dimensionally arranged protein monomers to form bionanotubes are promising in terms of innate biocompatibility, easy bio-conjugation to incorporate multiple functionalities and well-defined nano-scale lengths. Such unique chemical properties of protein assemblies are described in this review.     

Explanation of impact load curve in ball impact test in relation to thermal aging

Solder joints are required to have high impact strength for use in portable electronic products. To make solder joints with high impact strength, qualitative evaluation methods of impact strength are required. Ball impact tests have been widely adopted in evaluating the impact strength of solder joints because of their easy implementation. Impact load curves obtained from ball impact tests are used as an evaluation indicator of impact strength of solder joint. However, a relation between fracture behavior and impact load curve has not yet been clarified, and an explanation of the impact load curve has not yet been provided in detail. In addition to this, detailed study about the relation between IMC layer thickness and impact strength has not been performed, although the IMC layer thickness formed at the interface would significantly affect the impact strength of the solder joint. This study aimed to explain the impact load curve in the ball impact test and to reveal the effect of the IMC layer thickness on the impact strength of the solder joint. Sn–3.0Ag–0.5Cu solder was reflowed on an electroless Ni–P plated Cu substrate (Ni–P), and a ball impact test was then carried out to evaluate the impact strength. This study found that the ball impact test is effective to evaluate the interfacial strength of solder joints. In the impact load curve, it is estimated that the solder bump keeps deforming until the interfacial crack initiates (maximum load), and the interfacial crack initiates after the maximum load and propagates along the interface between the solder and Ni–P. The suitable evaluation of impact strength became possible by measuring the correspondence relation between the deformation distance of the solder bump after fracture and the energy until maximum load and the relation between the area fraction of the residual solder on the fractured pad and the energy after maximum load. And, it is proved that the impact strength decreased with increasing aging time because the growth of the IMC layer remarkably degraded the interfacial strength of the solder joint.     

Magnetic Field Effect on Chemical Compositions of Magnetic Aerosol Particles Synthesized Photochemically from a Gaseous Mixture of Iron Pentacarbonyl and Trimethylsilyl Azide

Under intense UV light irradiation with an Nd:YAG laser at 355 nm, a gaseous mixture of iron pentacarbonyl (Fe(CO)₅) and trimethylsilyl azide (TMSAz) produced aerosol magnetic particles with diameters of 50–100 nm. Two photon absorption of TMSAz and Fe(CO)₅ took place efficiently to produce trimethylsilyl nitrene and iron carbonyls (Fe(CO) _n n = 1–4). In cases where a partial pressure of TMSAz was high, nucleation reactions of aerosol particles proceeded via chemical reactions between trimethylsilyl nitrene and two iron carbonyls, resulting in bridging between two iron carbonyls by silyl nitrene. In cases where a partial pressure of TMSAz was low, the nucleation reactions proceeded via chemical reactions between two iron carbonyls, resulting in the formation of di-iron carbonyls with bridging >C?O group. Both of these nucleation reactions took place concurrently during aerosol particle formation. From FT-IR spectral change of sedimentary particles produced under an external magnetic field of up to 5 T, it was found that application of an external magnetic field accelerated the latter chemical reaction to result in the appearance of bridging ν(>C?O) band in FT-IR spectrum of the magnetic particles.

Copyright 2013 American Association for Aerosol Research     

Formation of Silicate-Added (Bi,La)4Ti3O12 Films on LaAlO3/Si(100) Structures

We fabricated MFIS (metal-ferroelectric-insulator-semiconductor) diodes with ((Bi,La)₄Ti₃O₁₂: BLT) films and lanthanum silicate (La₂SiO₅: LSO)-added BLT films formed on LaAlO₃/Si(100) structures. LaAlO₃ films were prepared by an MBD (molecular beam deposition) method. After the film deposition, they were subjected to ex site N₂ annealing in a rapid thermal annealing (RTA) furnace at 800°C for 1 min. BLT films and LSO-added BLT films were deposited on these LaAlO₃/Si structures using a sol-gel technique. The memory windows of BLT and LSO-added BLT films were 3.0 V and 2.1 V, respectively. It was found from the current density-voltage (I-V) characteristics that the insulation property of the LSO-added BLT film was superior to that of the BLT film. We conclude from these results that LaAlO₃ is an excellent candidate of a buffer layer for forming ferroelectric-gate FETs and that the LSO-added BLT film is suitable for low voltage operation of the FETs.     

Preparation of Si-Added SrBi2Ta2O9 Ferroelectric Thin Films by RF Magnetron Sputtering

Si-added SrBi₂Ta₂O₉ (SBT) ferroelectric films were prepared by RF magnetron sputtering on a Pt/Ti/SiO₂/Si (100) structure. The films were deposited at temperatures below 100°C for surpressing Bi evaporation, and crystallized at 800°C in air. A typical composition was Sr_0.79Bi_2.37Ta_2.00Si_0.2O_x. The remanent polarization value (2Pr) of the Si-added SBT film was 16 μC/cm². The Si atom addition was found to be effective in improvement of the fatigue and leakage current of SBT ferroelectric films. The leakage current density was further improved by annealing in the high-pressure oxygen ambient at 7 atms.     

Dielectric relaxation phenomenon of rare earth Nd3+ modified bismuth layer ferroelectric ceramics fabricated by plasma active sintering method

Abstract

The crystalline structure, dielectric relaxation and ferroelectric properties of the solid solution, Nd _x Bi_4-x Ti₃O₁₂ (NBIT) compound were measured. The Curie temperature of the NBIT ceramics was determined to be 490°C from dielectric measurements. The dielectric constant of the NBIT ceramics shows a small anisotropic property. Polarization switching was observed using a Sawyer-Tower circuit at 50 Hz. Remnant polarizations and coercive fields could not be confirmed since the hysteresis loops were not saturated. The large dielectric relaxation is observed in the frequency range between 100 kHz and 1 MHz.     

A study on cubic boron nitride (CBN) milling of hardened cast iron for productive and quality manufacturing of machine tool structural components

To improve efficiency and cost performance of cast iron machine tool component fabrication, an alternative process must be developed in order to replace the grinding process, which often causes a bottleneck in production. As an alternative manufacturing approach, this research applies cubic boron nitride (CBN) hard milling operations to eliminate the grinding process in order to improve the overall manufacturing process. A variety of hardened cast iron materials with Al and Mg additives and CBN tool types were prepared and tested based on a design of experimentation (DOE) to observe their effect on surface quality and tool life. Al and Mg were added to raw cast iron to achieve generation of oxide layers at the cutting edge during milling to protect the tool from wear. By executing the DOE, the optimal cutting conditions for achieving the best surface quality were introduced. Also, additional machinability tests were conducted with the optimal conditions in order to evaluate tool wear characteristics and surface quality of the machined workpieces. Based on the observation of the used tool by electron probe micro-analyzer (EPMA), a protective oxide layer of additives was observed at the cutting edge. Hardened cast iron with Al and Mg additives is found to show preferable wear and surface quality characteristics.