Investigation of the electrothermo-optical effect of a smectic LCP–nematic LC–chiral dopant ternary composite system based on SA ↔ N* phase transition

A sharp change in transmittance from a transparent state to a light scattering one within a tiny temperature range is induced accompanied with the heat-induced phase transition from a smectic-A (S_A) phase to a chiral nematic (N*) one in a side-chain smectic-A liquid crystalline polymer (S_ALCP)–low-molecular-weight nematic liquid crystal (NLC)–chiral dopant ternary composite system with a homeotropic boundary condition. By adjusting the polymer ratio, an induced N* phase exhibiting strong light scattering over a wide temperature region has been obtained. The resulting scattering texture retained in the S_A phase due to fast cooling from the N* phase can be rather stable and can be easily erased by cooling slowly from the N* phase to the S_A phase after the scattering texture being heated into the N* phase again or by application of an alternating current electric field on the scattering texture directly. Based on these characteristics, it is very possible that this composite system will be used as a novel thermal addressed liquid crystal display material with respect to a fast response, a high contrast, and a durable memory effect. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 623–631, 1999     

On-demand patterning of protein matrixes inside a microfluidic device

On-demand immobilization of proteins at specific locations in a microfluidic device would advance many types of bioassays. We describe a strategy to create a patterned surface within a microfluidic channel by electrochemical means, which enables site-specific immobilization of protein matrixes and cells under physiological conditions, even after the device is fully assembled. By locally generating hypobromous acid at a microelectrode in the microchannel, the heparin-coated channel surface rapidly switches from antibiofouling to protein-adhering. Since this transformation allows compartmentalizing of multiple types of antibodies into distinct regions throughout the single microchannel, simultaneous assay of two kinds of complementary proteins was possible. This patterning procedure can be applied to conventional microfluidic devices since it requires only some electrodes and a voltage source (1.7 V, DC).     

共沉淀法制备Al2O3-YAG复相陶瓷及其显微结构研究

用共沉淀法制备了Ａl2O3-YAG复合粉体,ＹＡＧ的结晶温度在１０００℃左右,共沉淀法制备的Ａl2O3-YAG复合粉体经１５５０℃热压烧结,获得致密烧结体,ＹＡＧ的加入量对烧结温度的影响不大。Ａl2O3-5vol%YAG复合材料的抗弯强度为６０４ＭＰa,断裂韧性为５．０ＭＰa.m%^1/2;Al2O3-25vol%YAG复合材料的抗弯强度为６１１ＭＰa,断裂专访性为４．５ＭＰa.M^1/2。所有这些数据都高于单相Ａl2O3陶瓷的力性能,说明ＹＡＧ的加入有利于Ａl2O3陶瓷力学性能的提高。通过显微结构观察发现：大的ＹＡＧ颗粒位于Ａl2O3晶界上,小的ＹＡＧ颗粒位于Ａl2O3晶粒内。在Ａl2O3-5vol%YAG复合材料中,许多小的白色区域存在于Ａl2O3晶粒内,这可能和较低的Ｙ２Ｏ３含量有关。     

Electrodeposition of Inorganic/Organic Hybrid Thin Films

Electrodeposition of inorganic compound thin films in the presence of certain organic molecules results in self‐assembly of various hybrid thin films with new properties. Examples of new discoveries by the authors are reviewed, taking cathodic formation of a ZnO/dye hybrid as the leading example. Hybridization of eosinY leads to the formation of highly oriented porous crystalline ZnO as the consequence of dye loading. The hybrid formation is a highly complicated process involving complex chemistry of many molecular and ionic constituents. However, electrochemical analyses of the relevant phenomena indicate the possibility of reaching a comprehensive understanding of the mechanism, giving us the chance to further develop them into industrial technologies. The porous crystals are ideal for photoelectrodes in dye‐sensitized solar cells. As the process also permits the use of non‐heat‐resistant substrates, the technology can be applied for the development of colorful and light‐weight plastic solar cells.     

Growth condition dependence of structural and electrical properties of Mg2Si layers grown on silicon substrates

Mg₂Si layers were grown on Si substrates by thermal treatment of the substrates in a Mg vapor, and the growth condition dependence of the structural and electrical properties of the layers was investigated. The layers were grown by an interdiffusion process between the deposited Mg atoms and the substrates. The structural and electrical properties of the layers depend on the combinations of the Si substrate and Mg source temperatures during the heat treatment. Any deviation from the isothermal treatment conditions causes degradation of the structural and/or electrical properties of the Mg₂Si layers. It was confirmed that the layers with the optimum structural and electrical properties were obtained when the layers were grown under isothermal growth conditions.     

High-rate performance of all-solid-state lithium secondary batteries using Li4Ti5O12 electrode

The all-solid-state Li–In/Li₄Ti₅O₁₂ cell using the 80Li₂S·20P₂S₅ (mol%) solid electrolyte was assembled to investigate rate performances. It was difficult to obtain the stable performance at the charge current density of 3.8 mA cm⁻² in the all-solid-state cell. In order to improve the rate performance, the pulverized Li₄Ti₅O₁₂ particles were applied to the all-solid-state cell, which retained the reversible capacity of about 90 mAh g⁻¹ at 3.8 mA cm⁻². The 70Li₂S·27P₂S₅·3P₂O₅ glass–ceramic, which exhibits the higher lithium ion conductivity than the 80Li₂S·20P₂S₅ solid electrolyte, was also used. The Li–In/70Li₂S·27P₂S₅·3P₂O₅ glass–ceramic/pulverized Li₄Ti₅O₁₂ cell was charged at a current density higher than 3.8 mA cm⁻² and showed the reversible capacity of about 30 mAh g⁻¹ even at 10 mA cm⁻² at room temperature.     

Heat storage-type floor heating system with heat pump driven by nighttime electric power

We performed tests for heat storage-type floor heating that employs a heat pump driven with nighttime electric power for 8 h (11 PM to 7 AM) as the heat source. The phase change material (PCM) applied was a package of mirabilite (Na₂SO₄ · 10H₂O). The melting point is 32 °C, the freezing point 30 °C, and the stored heat amount 43 W · h/kg (ΔT = 10 °C). The test room for floor heating was a wooden structure without windows, and the floor area was 40 m². The hot water panel (5 mm in thickness, made of plastic, 26 m²) was laid on the stage (1.2 m in height) inside the room and the PCM was superimposed on the upper surface of the stage (the total stored heat amount was 28.5 kW). Since the heat pump runs in cycles of 8-h operation and 16-h nonoperation, it needs an extracted heat amount of three times compared with the case of round-the-clock operation. For this reason, we have developed a wet film-type vertical heat extracting tube with a built-in Freon flashing pump to obtain extracted heat about three times greater than was previously possible. We have calculated the heat balance from the results of the tests for floor heating and have studied the practicability of this system. © 1998 Scripta Technica, Inc. Heat Trans Jpn Res, 26(2): 122–130, 1997     

Development and characteristics of servomotor for use under high temperature and radiation flux conditions

Recently, robots have been required to inspect the insides of nuclear reactors under high temperature and radiation flux conditions. In a FBR (fast breeder reactor), the viewing system of the robot is particularly important because the reactor vessel of the FBR is filled with opaque liquid sodium. To drive this robot, servomotors must meet special requirements. At temperatures above 220°C, the integrity of organic materials cannot be maintained for long periods. In addition, the air-gap length of the motor varies, because metals expand at high temperatures. Thus, the characteristics of induction motors with an air-gap length of 0.2–0.4 mm may vary. Furthermore, the rotor may come into contact with the stator. In this paper, a newly developed permanent magnet motor which can withstand high temperatures and radiation is presented, and the characteristics of the rotor at high temperatures are discussed. Coils for winding ceramic magnetic wires are installed in the stator and Sm₂Co₁₇ permanent magnets are embedded in the rotor yoke. This motor is suitable for use at up to 400°C due to the use of inorganic materials in it. In addition, the permanent magnet motor can incorporate a long air-gap length, which has little effect on the characteristics of the motor. The test results show that the motor has excellent characteristics at high temperature. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 119(4): 52–65, 1997     

Vitamin C Maintenance against Cell Growth Arrest and Reactive Oxygen Species Accumulation in the Presence of Redox Molecular Chaperone hslO Gene

Chromosome damage combined with defective recombinase activity renders cells inviable, owing to deficient double-strand break repair. Despite this, recA polA cells grow well under either DNA damage response (SOS) conditions or catalase medium supplementation. Catalase treatments reduce intracellular reactive oxygen species (ROS) levels, suggesting that recA polA cells are susceptible to not only chronic chromosome damage but also ROS. In this study, we used a reducing agent, vitamin C, to confirm whether cell growth could be improved. Vitamin C reduced ROS levels and rescued colony formation in recAts polA cells under restrictive temperatures in the presence of hslO, the gene encoding a redox molecular chaperone. Subsequently, we investigated the role of hslO in the cell growth failure of recAts polA cells. The effects of vitamin C were observed in hslO⁺ cells; simultaneously, cells converged along several ploidies likely through a completion of replication, with the addition of vitamin C at restrictive temperatures. These results suggest that HslO could manage oxidative stress to an acceptable level, allowing for cell division as well as rescuing cell growth. Overall, ROS may regulate several processes, from damage response to cell division. Our results provide a basis for understanding the unsolved regulatory interplay of cellular processes.