Analysis of thickness-extensional waves propagating in the lateral direction of solidly mounted piezoelectric thin film resonators

In a solidly mounted piezoelectric thin film resonator (SMR), acoustic waves propagate not only in the thickness direction but also in the lateral direction. In this study, we analyzed the acoustic wave in the SMR-type piezoelectric thin film resonator and derived the dispersion relation between the lateral wave number and frequency, considering wave propagation in the lateral direction. The lateral wave number was shown to be a complex number due to the leak of the acoustic energy to a substrate. It also was shown that the Q factor could be calculated from the complex cutoff frequency, and it becomes higher when the number of quarter-wave (lambda/4) layers increases. Using the dispersion relation, the trapped-energy resonant modes of an SMR were analyzed, considering the boundary conditions at the edge of the electrode.     

Temperature alternation by an on-chip microheater to reveal enzymatic activity of beta-galactosidase at high temperatures

A method to measure enzymatic activity at high temperatures by rapid temperature alternation of a microreactor with a microheater is proposed. On-chip microreactor and microheater were integrated on a glass plate by MEMS technology; this microheater can control the temperature of the microreactor with a response speed of 34.2 and 31.5 K/s for temperature rise and fall, respectively, with an accuracy of 3 degrees C. The enzyme, beta-galactosidase, was revealed to survive short exposure (4-s pulses) to temperatures above that which would "normally" denature them. Its activity at 60 degrees C was revealed to be approximately 4 times greater than that at room temperature. This method not only gives new kinetic information in biochemistry but also enables application in highly sensitive biosensors.     

Fundamental insulation characteristic of high-pressure CO/sub 2/ gas under actual equipment conditions

SF₆ gas has been widely used in electrical power equipment such as circuit breakers and transformers due to its superior insulation and interruption characteristics. However since 1997, SF₆ gas has been designated a greenhouse gas subject to emission restrictions at COP3 (The 3rd session of the Conference Of the Parties to the United Nations Framework Convention on Climate Change) so a new insulating gas is needed as a substitute for SF₆ gas. This research considers the use of high-pressure CO₂ gas as an insulator while stressing the environment aspects. Fundamental insulation data for the insulating gas acquired supposing gas insulated switchgears (GIS) consists of; (1) insulation breakdown characteristics under clean conditions and, (2) insulation breakdown characteristics with metallic particle contamination. The parameters in this case were assumed from an actual apparatus viewpoint, to be a high gas pressure up to 2.0 MPa, an electrode size capable of determining the surface area effect, the electrode surface roughness, and metallic particle length, etc. at the base electrode of the 72 kV GIS. As a result, experiments using these parameters revealed insulation characteristics for high-pressure CO₂ gas and that negative lightning impulse decided the insulation design, as well as the present SF₆ GIS. The need for taking measures to suppress PD under AC voltage and also the need for restricting metallic foreign particles around the central conductor and insulating spacer were recognized     

A RaPID Macrocyclic Peptide That Inhibits the Formation of α-Synuclein Amyloid Fibrils

There is considerable interest in drug discovery targeting the aggregation of α-synuclein (αSyn) since this molecular process is closely associated with Parkinson's disease. However, inhibiting αSyn aggregation remains a major challenge because of its highly dynamic nature which makes it difficult to form a stable binding complex with a drug molecule. Here, by exploiting Random non-standard Peptides Integrated Discovery (RaPID) system, we identified a macrocyclic peptide, BD1, that could interact with immobilized αSyn and inhibit the formation of fibrils. Furthermore, improving the solubility of BD1 suppresses the co-aggregation with αSyn fibrils while it kinetically inhibits more effectively without change in their morphology. We also revealed the molecular mechanism of kinetic inhibition, where peptides bind to fibril ends of αSyn, thereby preventing further growth of fibrils. These results suggest that our approach for generating non-standard macrocyclic peptides is a promising approach for developing potential therapeutics against neurodegeneration.     

Spirulina platensis Culture with Flue Gas Feeding as a Cyanobacteria‐Based Carbon Sequestration Option

The scientific community is currently examining potential approaches in order to reduce the anthropical contributions to global warming. One approach is carbon capture and its storage, i.e., capturing CO₂ at its source and storing it indefinitely to avoid its release into the atmosphere. Conversion of CO₂ by microalgae or cyanobacteria is a sequestration option. Here, the application of an air‐lift reactor to flue gas treatment using cyanobacteria for the absorption of CO₂ was investigated, with the simultaneous abatement of NO_x. A Spirulina platensis culture was fed with CO₂ and NO_x, simulating a flue gas. The preliminary test yielded positive indications on the process feasibility, both in terms of cell productivity (86.8 mg L^–1d^–1) and CO₂ abatement (229 mg d^–1). Opportune dosages of flue gas used in fed‐batch test achieved a high abatement of CO₂ (407 mg d^–1), 90.0 % removal of NO_x, and a biomass production of 188.7 mg L^–1d^–1.     

Synthesis of Block Copolymers containing Chain‐Controlled Aramid and Fluoroethylene Segments

Summary: Novel block copolymers containing aromatic polyamide (aramid) and fluoroethylene segments were synthesized by a two‐step solution polycondensation. This synthetic method could control the chain‐length of aramid segments and these copolymers could have high structural regularity. The number‐average molecular weight ( ) of one of these polymers is over 2.0 × 10⁴. Incorporating fluoroethylene segments improves the solubility of the resulting polymer compared with conventional aramids.

The synthesis of the fluoroethylene‐aramid block copolymers.     

A new facility for investigation on neutron irradiation effect on superconducting properties of Nb3Sn strand for fusion magnet

To perform post irradiation tests of superconducting strands, a 15.5 T superconducting magnet and a variable temperature insert (VTI) were installed at a radiation control area in Oarai center, Institute for Materials Research, Tohoku University. Both of the 15.5 T magnet and the VTI are conductively cooled with GM refrigeration. The commissioning test of the system is still ongoing because unexpected troubles occurred during the commissioning. Also, a SQUID system with the maximum field of 7 T has been installed at another radiation control area to investigate the magnetic property of uranium and its isotopes. These devices are very useful to study the electro-magnetic properties of the neutron irradiated superconducting strands. This paper will introduce the new superconducting test facility, and some data recently obtained will be presented together with the data of magnetization evaluated with the SQUID, and the discussion on the irradiation effect on superconducting properties will be performed.     

中国国际建筑艺术实践展会议中心

本设计充分结合地形特征，把整个国际会展中心设施布置在自然环抱的山谷之中，并通过将拥有大会议室和拥有中会议室及办公室的两栋细长条的主体建筑与山谷轴线正交布置，     

Tensile properties of glassy MgZnCa wires and reliability analysis using Weibull statistics

Mg-based metallic glass wires were produced via the melt-extraction technique. Their mechanical properties were evaluated by carrying out tensile tests on electrochemically polished dogbone-shaped wire samples, and their reliability was estimated using Weibull analysis. The wires exhibit a tensile strength of 675–894 MPa with a characteristic strength of 817 MPa and a Weibull modulus of 20.6. The high Weibull modulus is explained by the plastic behavior and necking of the tensile samples. The tensile tests also reveal an extended amount of homogeneous plastic deformation, which can be assigned to the circular geometry and flawless surface quality of the specimens.