A New Approach to Suppress the Effect of Machining Error for Waveguide Septum Circular Polarizer at 230 GHz Band in Radio Astronomy

A new stepped septum-type waveguide circular polarizer (SST-CP) was developed to operate in the 230 GHz band for radio astronomy, especially submillimeter-band VLBI observations. For previously reported SST-CP models, the 230 GHz band is too high to achieve the design characteristics in manufactured devices because of unexpected machining errors. To realize a functional SST-CP that can operate in the submillimeter band, a new method was developed, in which the division surface is shifted from the top step of the septum to the second step from the top, and we simulated the expected machining error. The SST-CP using this method can compensate for specified machining errors and suppress serious deterioration. To verify the proposed method, several test pieces were manufactured, and their characteristics were measured using a VNA. These results indicated that the insertion losses were approximately 0.75 dB, and the input return losses and the crosstalk of the left- and right-hand circular polarization were greater than 20 dB at 220–245 GHz on 300 K. Moreover, a 230 GHz SST-CP was developed by the proposed method and installed in a 1.85-m radio telescope receiver systems, and then had used for scientific observations during one observation season without any problems. These achievements demonstrate the successful development of a 230 GHz SST-CP for radio astronomical observations. Furthermore, the proposed method can be applicable for observations in higher frequency bands, such as 345 GHz.     

Modification of physicochemical properties of actin filaments suppresses cell fragmentation in the execution phase of staurosporine-induced apoptotic processes

Effects of jasplakinolide (JSP), a stabilizer of F-actin, and latrunculin A (LTA), a destabilizer of F-actin, on a series of events occurring in the execution phase of staurosporine (STS)-induced apoptotic processes were studied using human osteosarcoma 143B cells. Time-dependent apparent increases of the population of cells with collapsed membrane potential of mitochondria (Delta Psi(m)) caused by STS treatment were not due to actual decreases in the Delta Psi(m) per cell, but due to the fragmentation of cells resulting in decreases in the number of active mitochondria per cell. Decreases in the Delta Psi(m) in fragmented cells occurred late in the execution phase. Both JSP and LAT failed to prevent STS-induced release of cytochrome c from mitochondria followed by the activation of caspases 3 and 9, the cleavage of poly (ADP-ribose) polymerase (PARP) and apoptotic nuclear fragmentation. However, both drugs prevented STS-induced apoptotic cell fragmentation and decreases in the Delta Psi(m). These results indicate that physicochemical states of actin filaments play a certain role in the execution phase of STS-induced apoptotic processes.     

Silicon based on-chip antenna using an LC resonator for near-field RF systems

This paper presents the silicon based on-chip antenna using a LC resonator. The proposed antenna consists of a stacked capacitor and a spiral inductor on silicon substrate. The spiral inductor structure without underpass was proposed for improvement the performance of the silicon based-antenna. The resonant frequency of the fabricated antenna was measured as 465 MHz. Its return loss was 23.4 dB at resonant frequency. The antenna has a gain of ?35.75 dBi due to small size and silicon substrate. However, the fabricated antenna has good performance in the near-field.     

Performance enhancement of partially and fully depleted strained-SOI MOSFETs

The authors have developed short-channel strained-silicon-on-insulator (strained-SOI) MOSFETs on silicon-germanium (SiGe)-on-insulator (SGOI) substrates fabricated by the Ge condensation technique. 35-nm-gate-length strained-SOI MOSFETs were successfully fabricated. The strain in Si channel is still maintained for the gate length of 35 nm. The performance enhancement of over 15% was obtained in 70-nm-gate-length strained-SOI n-MOSFETs. Fully depleted strained-SOI MOSFETs with back gate were successfully fabricated on SGOI substrate with SiGe layers as thin as 25 nm. The back-gate bias control successfully operated and the higher current drive was obtained by a combination of the low doping channel and the back-gate control.     

ArF excimer laser induced CVD of aluminum oxide films

The authors have demonstrated photochemical deposition of aluminum oxides from Trimethylaluminum (TMA) and N₂O by using a pulsed ArF excimer laser (193 nm). Both TMA and N₂O are efficiently photodissociated by the 193 nm light. The films are grown on Si and InP wafers contained in a low pressure flowing cell with a heated substrate. The incident laser beam is focused and parallel to the substrate surface. Typical deposition rates are 80–150 A/min. Stripes of aluminum oxide 30 mm wide are uniformly grown on 7.5 cm Si-wafers. The film composition and purity have been investigated using Auger and Infra-red spectroscopy analysis. Surprising results are the relatively low concentration of carbon. Refractive index and thickness have been determined by an ellipsometer. Typical values for the films are 1.54–1.62. Metal-oxide-semiconductor capacitors have been fabricated and characterized. The C-V curves for n-InP/aluminum oxide have clockwise hysteresis, and minimum loop width is less than 0.5 V. The surface state densities are 1 × 10¹¹ cm^-2 eV⁻¹ at the mid band gap.     

Full Eulerian deformable solid-fluid interaction scheme based on building-cube method for large-scale parallel computing

We propose a full Eulerian incompressible solid-fluid interaction scheme capable of achieving high parallel efficiency and easily generating meshes for complex solid geometries. While good scalability of a full Eulerian solid-fluid interaction formulation has been reported by Sugiyama et al, their analysis was carried out using uniform Cartesian mesh and an artificial compressibility method. Typically, it is more challenging to achieve good scalability for hierarchical Cartesian meshes and a fully incompressible formulation. In addition, the conventional full Eulerian methods require a large computational cost to resolve complex solid geometries due to the usage of uniform Cartesian meshes. In an attempt to overcome the aforementioned issues, we employ the building-cube method, where the computational domain is divided into cubic regions called cubes. Each cube is divided at equal intervals, the same number of cubes is assigned to each core, and the spatial loop processing is executed for each cube. The numerical method is verified by computing five numerical examples. In the weak scaling test, the parallel efficiency at 32768 cores with 32 cores as a reference is 93.6%. In the strong scaling test, the parallel efficiency at 32768 cores with 128 cores as a reference is 70.2%.     

Proposals for wastewater treatment by applying flocculating activity of cross-linked poly-gamma-glutamic acid

Cross-linked poly-gamma-glutamic acid (C-L gamma-PGA) markedly purified polluted water collected from rivers and ponds by flocculation and precipitation. This effect of C-L gamma-PGA occasionally required pretreatment with polyaluminum chloride (PAC). Components of polluted water in rivers or ponds are generally thought to be clay minerals, microorganisms and chemical compounds. In this study, the flocculating activities of C-L gamma-PGA against suspensions of bentonite, diatomaceous earth, Escherichia coli and Mycrocystis aeruginosa, and against solutions of crystal violet and bisphenol A were investigated. The mode of action of C-L gamma-PGA is thought to be based on electrostatic interaction between flocculants, C-L gamma-PGA and PAC, and the surface of polluted water components, which may lead to neutralization of the zeta-potential of those components.     

Utilization of Lactoferrin as an Iron-Stabilizer for Soybean and Fish Oil

ABSTRACT: We investigated the oxidative stability of soybean oil and fish oil fortified with iron solubilized by lactoferrin (FeLF). Oxidative stability was evaluated by measuring the induction period of the Rancimat test. The induction time of soybean oil added FeCl₃ was decreased; however, that of added FeLF was not. This effect of lactoferrin was also observed in the iron-catalyzed oxidation offish oil at temperatures ranging from 50°C to 120°C, and at concentrations of iron ranging from 0 to 500 ppm. Thus, lactoferrin is considered useful as a natural iron stabilizer for food products containing polyunsaturated fatty acids.     

A short‐cut DNA extraction from cod caviar

Caviars represent the most consumed form of fish roe products. Due to high demand, ingredient roes of fish are often susceptible to illegal substitution with those of related fish. This study developed a simple and inexpensive protocol enabling the rapid extraction of DNA of acceptable quality and amount to PCR amplification from both cod caviars and their ingredient pollack roes. The protocol was based on extracting total genomic DNA from eggs using urea and a Chelex 100 chelating resin, and could be completed in less than 15 min. Approximately 8 µg of DNA were reproducibly obtained from single eggs of cod caviars and pollack roes in eight individual experiments, and the quality and amount of DNA were sufficient to serve as template for hundreds of PCR reactions of polymorphic DNA markers for phylogenetic analysis. Being applicable to various caviars, this protocol can be useful to detect illegal substitution among ingredient roes of related fishes in PCR‐based food inspection. Copyright © 2005 Society of Chemical Industry