Synthesis and property of 9,9′-spirobifluorene-containing aromatic polyesters as optical polymers with high refractive index and low birefringence

C₂-Symmetric 9,9′-spirobifluorene-containing polyesters (PEs) were synthesized by polycondensation of 2,2′-dihydroxy-9,9′-spirobifluorene (1) with bis(acyl chloride)s (2) at 230 °C in diphenylether. The molecular weights of PEs 3a-3f were sufficiently high (M_w 13,400-41,600). PEs displayed high thermal stability. The glass transition temperatures (T_g) estimated by differential scanning calorimetry analysis appeared in a range 177-352 °C depending on the spacer structure, while the 5% decomposition temperatures (T_d5) measured by thermogravimetric analysis were over 416 °C both under nitrogen atmosphere and in air. PEs showed good solubility in typical organic solvents such as CHCl₃ and THF easily to afford the tough, transparent, and flexible cast films. The transmittance of the polymer films reached over 90% in the wavelength range from ca. 410-900 nm. In addition, PEs exhibited higher refractive index rather than that of commercially available 9,9-diarylfluorene-containing PE, in addition to very low degree of birefringence presumably due to the C₂-symmetric structure.     

Adsorption Potentials and Film Growths of 4He in Nanometer Pores of FSM-16 (2.8 nm) and HMM-2 (2.7 nm)

No Heading To find the one- and the three-dimensionalities for the superfluid onset of the ⁴He films formed in nanopores, we have been studying ⁴He adsorbed on FSM-16 and HMM-2 that have pores of almost the same diameter, 2.8 and 2.7 nm, but ID and 3D connections of the pores, respectively. For these two substrates, the adsorption potential profile and layer-by-layer growth of ⁴He films were observed by the precise measurement of the vapor pressure for adsorption. The isothermal compressibility _T, the film thickness d, and the isosteric heat q_st of adsorption are derived from the vapor pressure. _T and d indicate that ⁴He adatoms form uniform layers up the second layer on both substrates. Almost the same q_st for both substrates suggest that the adsorption potential is the same between these SiO₂-based substrates. These results suggest that FSM-16 and HMM-2 are ideal substrates to use in investigating the dimensionality of the superfluid onset.PACS numbers: 67.40.–w, 67.70.+n     

Three dimensional measurement of nanostructures by single event TOF-RBS with nuclear nano probe

Single, double and triple-layer test structures were measured by time of flight (TOF) Rutherford backscattering spectrometry (RBS) for checking the sensitivity and resolution. A single-layer nanostructure with Au stripes on a Si substrate was resolved by TOF-RBS measurement within a short time of 256 s. The spatial resolution, measured by the edge of the Au stripes, was 42 nm. Another single-layer nanostructure with Pt stripes fabricated by electron beam (EB) induced deposition on a Si substrate was resolved by TOF-RBS measurement even at a thickness of Pt stripes less than one mono-layer. Ga embedded layers implanted by a focused ion beam under the Pt stripes fabricated by EB induced deposition on a Si substrate could be detected for a double-layer nanostructure. Furthermore, a triple-layer nanostructure with two Pt stripe layers isolated by a SiO₂ layer fabricated by EB induced deposition on a Si substrate could be resolved and cross-sections shown.     

Effect of γ-Cyclodextrin Inclusion Complex on the Absorption of R-α-Lipoic Acid in Rats

R-α-lipoic acid (RLA) is an endogenous organic acid, and works as a cofactor for mitochondrial enzymes and as a kind of antioxidant. Inclusion complexes of RLA with α-, β- or γ-cyclodextrins (CD) were prepared and orally administered as a suspension to rats. Among them, RLA/γ-CD showed the highest plasma exposure, and its area under the plasma concentration-time curve (AUC) of RLA was 2.2 times higher than that after oral administration of non-inclusion RLA. On the other hand, the AUC after oral administration of non-inclusion RLA and RLA/γ-CD to pylorus-ligated rats did not differ. However, the AUC after intraduodenal administration of RLA/γ-CD was 5.1 times higher than that of non-inclusion RLA, and was almost comparable to the AUC after intraduodenal administration of RLA-Na solution. Furthermore, the AUC after intraduodenal administration of RLA/γ-CD was not affected by biliary ligation or co-administration of an amylase inhibitor. These findings demonstrated that RLA was absorbed from the small intestine effectively when orally administered as a γ-CD inclusion complex, which could be easily dissolved in the lumen of the intestine. In conclusion, γ-CD inclusion complex is an appropriate formulation for supplying RLA as a drug or nutritional supplement with respect to absorption.     

Faults and Claims about Thermal Environments in Relation to Energy Saving Measures in Smaller Office Buildings

Building equipment, energy-saving systems, and claims of inappropriate indoor thermal environments were analyzed in relation to the floor area using responses to a questionnaire survey of service managers of 157 buildings built in Osaka, Kyoto and Hyogo prefectures in Kinki area of Japan. Results show the following： （1） In smaller buildings （〈 5,000 m2）, setting temperatures are higher in summer and lower in winter, effects of ＂uncomfortable radiation from windows＂ are greater, energy-saving systems decrease indoor thermal comfort, but claims of ＂hot＂ and ＂cold＂ are fewer; （2） Claims of ＂hot＂ and ＂cold＂ are unrelated to the setting temperature and whether the air-conditioning control system is central or local; （3） The adoption rates of mitigation of dress codes （＂COOL-BIZ＂ and ＂WARM-BIZ＂） are higher than those of temperature mitigation of air conditioning.     

Carbon nanotube sheets used in field-emission lamps with vacuum-sealed diode structures

We applied carbon nanotube (CNT) sheets, which are high-purity and suitable for mass production, to field-emission lamps (FELs) with vacuum-sealed diode structures. Three such FELs were designed and fabricated to correspond to the field-emission characteristics of individual CNT sheets. We suppressed the variation in the anode–cathode voltage to within the range of 5.4–6.0 kV, which contributes to the light output of the FELs. The stabilities of the FELs ranged from ?0.65% to 0.26% in the short term; therefore, we confirmed that the high-purity CNT sheets were stable during operation. All FELs could be operated for 500 h without significant degradation, even when the FEL was operated in a passive vacuum instead of a dynamic vacuum.     

Measurement System for Flexed Shape of Flexibly Articulated Mobile Track

This paper proposes and validates a system for measuring the flexed posture of the flexible mono-tread mobile track (FMT) using a flexible displacement sensor (FDS). The FMT proposed previously has a single track and vertebral structure. The flexed posture of the FMT determines its turning radius and direction; thus, knowing its posture is important. However, it is impossible to measure the shape of flexible mobile systems using sensors located internally, such as a rotary potentiometer, or located externally, such as a laser scanner. To solve the problem, we introduce the FDS to measure the flexed FMT shape. The sensor consists of two fixed electrodes, a sliding electrode, and a nylon string coated with carbon (NSCC). It works as a flexible potentiometer by moving the sliding electrode along the NSCC while maintaining electrical contact. The measurement system is implemented in a prototype of the FMT called RT02-WORMY and is validated in a series of experiments.     

Omnidirectional Control of Large Electrical Output in a Topological Antiferromagnet

Control of magnetization direction is essential for the wide application of ferromagnets; it defines the signal size of memory and sensor. However, the magnetization itself causes a dilemma. While its size matters to obtain strong responses upon its reversal, the large magnetization concomitantly suppresses the range of its directional control because of the demagnetizing field. On the other hand, realization of the desired magnetic anisotropy requires careful engineering of crystalline and interfacial effects to overcome the demagnetization barrier. Thus, it would be ideal if one could find alternative magnets that carry no magnetization but strong responses. The discovery of a topological metallic state in the antiferromagnet Mn₃Sn is significant; they host a large Berry curvature in momentum space, enabling the observation of disproportionately large transverse responses such as anomalous Hall and Nernst effects, the key functionalities for replacing ferromagnets in the magnetic devices. Here, the experimental realization of omnidirectional control of the large responses in an antiferromagnet is reported. In particular, it is demonstrated that the absence of shape anisotropy enables the omnidirectional control, and lifts the shape constraint in designing the magnetic devices. This work lays the technological foundation for developing simple-structured high-performance devices including multi-level memory and heat flux sensor.