Basis Translation Matrix between Two Isomorphic Extension Fields via Optimal Normal Basis

This paper proposes a method for generating a basis translation matrix between isomorphic extension fields. To generate a basis translation matrix, we need the equality correspondence of a basis between the isomorphic extension fields. Consider an extension field F_p^m where p is characteristic. As a brute force method, when p^m is small, we can check the equality correspondence by using the minimal polynomial of a basis element; however, when p^m is large, it becomes too difficult. The proposed methods are based on the fact that Type I and Type II optimal normal bases (ONBs) can be easily identified in each isomorphic extension field. The proposed methods efficiently use Type I and Type II ONBs and can generate a pair of basis translation matrices within 15 ms on Pentium 4 (3.6 GHz) when mlog₂ p = 160.     

Correlated Postfiltering and Mutual Information in Pseudoanechoic Model Based Blind Source Separation

In a recent publication the pseudoanechoic mixing model for closely spaced microphones was proposed and a blind audio sources separation algorithm based on this model was developed. This method uses frequency-domain independent component analysis to identify the mixing parameters. These parameters are used to synthesize the separation matrices, and then a time-frequency Wiener postfilter to improve the separation is applied. In this contribution, key aspects of the separation algorithm are optimized with two novel methods. A deeper analysis of the working principles of the Wiener postfilter is presented, which gives an insight in its reverberation reduction capabilities. Also a variation of this postfilter to improve the performance using the information of previous frames is introduced. The basic method uses a fixed central frequency bin for the estimation of the mixture parameters. In this contribution an automatic selection of the central bin, based in the information of the separability of the sources, is introduced. The improvements obtained through these methods are evaluated in an automatic speech recognition task and with the PESQ objective quality measure. The results show an increased robustness and stability of the proposed method, enhancing the separation quality and improving the speech recognition rate of an automatic speech recognition system.     

Detailed Analysis of Temperature Characteristics of an InGaP/InGaAs/Ge Triple-Junction Solar Cell

Temperature characteristics of an InGaP/InGaAs/Ge triple-junction solar cell were analyzed in detail using an equivalent circuit calculation. The current–voltage (I–V) characteristics of single-junction solar cells (InGaP, InGaAs, Ge solar cells) were measured at various temperatures. Fitting of I–V curves between measured and calculated data was carried out, and the diode parameters and temperature exponents of the single-junction solar cells were extracted. The parameters for each single-junction solar cell were used in the equivalent circuit model for the triple-junction solar cell, and calculations of solar cell performance were carried out. Measured and calculated results of the I–V characteristics at various temperatures agreed well.     

Quasi-optical waveguide-mode converters using a pair of phase correction mirrors

This paper describes a quasi-optical method for the conversion of modes transmitted through highly oversized circular waveguides. A waveguide-mode is radiated once from a waveguide cut in the form of a radiation beam, which is then properly shaped by two curved mirrors and directed back into the waveguide. The curved mirror shapes are iteratively and automatically determined for given propagation distances using the design technique for phase correction mirrors. The proposed method gives favorable results in designing a waveguide expander/reducer, a TE₀₁-TE₀₂ mode converter, and a TE₀₁-HE₁₁ mode converter.     

Development of 170 GHz/500 kW gyrotron

A development of 170GHz/500kW level gyrotron was carried out as R&D work of ITER. The oscillation mode is TE_31,8. In a short pulse experiment, the maximum power of 750kW was achieved at 85kV/40A. The efficiency was 22%. In the depressed collector operation, 500kW/36%/50ms was obtained. The maximum efficiency of 40% was obtained at P_RF=470kW whereas the power decrease by the electron trapping was observed. Pulse extension was done up to 10s at P_RF=170kW with the depressed collector operation. The power was limited by the temperature increase of the output window.     

Syntheses of functional condensation polymers. II. A polyamide having epoxy groups and its ring-opening derivatives

Polyamides having epoxy groups and their ring-opening derivatives were prepared and characterized, and some of their properties were investigated. Reaction conditions for the low-temperature polycondensation of cis-2,3-epoxysuccinyl chloride (ESC) with aromatic diamines and the interfacial copolycondensation of ESC and adipyl chloride (AC) with aromatic diamines were established to obtain a high molecular weight polyamide having epoxy groups. In addition, the ring-opening reactions of the epoxy groups in the polyamides were carried out with various amines in order to obtain polyamides having hydrophilic pendent groups such as amino and hydroxyl. It was found that the polyamides prepared by ring-opening reaction of the epoxy group with ethylenediamine (EDA) or ethanolamine (EA) had a higher affinity for moisture than those with hexamethylenediamine (HMD) or n-butylamine (n-BA), which might be ascribed to the distance of hydrophilic groups from the polyamide chain. Those polyamides having hydrophilic pendent groups decomposed upon heating at less than 200°C.     

Dynamical System Analysis of Unsteady Phenomena inCentrifugal Compressor

INTRODUCTI0NUnsteadyphenomenaappearedinacentrifugalcompressorsystematlowflowratearecharacterizedbysurgeandrotatingstall.Thesurgeisknowntocauseoscillationswithlargeamplitudeofthefiowrateandthepressurerisethrough0utacompressorsys-tem.Ontheotherhand,ther0tatingstallcauseslocalflowoscillationsandappearsinsomepartsofacompressor,suchastheinducer,theimpellerandthediffuser-Sincetheydeterioratethecompressorperfor-manceands0metimesleadtothesystembreakd0wn,itisimportanttoknowthephysicalmechanismsofth…     

Promotion of initial cell adhesion on trisuccinimidyl citrate-modified nickel-free high-nitrogen stainless steel

The surface of nickel-free high-nitrogen stainless steel (HNS) was modified with a citric acid-based cross-linker, trisuccinimidyl citrate (TSC), to promote initial cell adhesion in external skeletal fixation pins. The remaining active ester groups on TSC-immobilized HNS reacted with the amino groups of serum proteins. The immobilized serum proteins formed cell recognition sites to promote the initial cell adhesion immediately after cell seeding. The amount of fibronectin, which is a typical cell adhesion protein, immobilized on the TSC-immobilized HNS surface was threefold greater than on the original HNS after only 15 min. The fibroblastic cell culture experiments showed that the initial cell adhesion was significantly enhanced on the TSC-immobilized HNS compared with the original HNS at 3 h. Furthermore, the cell adhesion activity of the TSC-immobilized HNS continued to promote cell proliferation even at 7 days. Therefore, TSC-immobilized HNS may enable the rapid integration of soft tissues through its reaction with the patient’s serum proteins and extracellular proteins around the surgical site.     

A new makeup remover prepared with a system comprising dual continuous channels (bicontinuous phase) of silicone oil and water

Removing makeup is considered to be the first step in the skincare process. Makeup that has served its purpose is a kind of impurity that should ideally be removed completely to maximize the effects of skincare products applied afterwards. However, the use of silicone resins has significantly improved the long‐lasting property of makeup with the result that makeup can hardly be removed efficiently either with surfactant‐type cleansers like soaps or with oil‐based cleansers like liquid crystalline cleansers. Furthermore, oil‐based makeup removers do not leave the skin feeling fresh but oily, and often have been used in combination with surfactant‐type cleansers. In other words, complete makeup removal and a fresh skin feel are considered to be incompatible in conventional formulation technologies. To obtain compatible systems, we investigated the applicability of a system known as the bicontinuous phase and eventually succeeded in developing a novel system for a makeup remover. This phase can be prepared with a specific composition with a complete hydrophilic‐lipophilic balance in an oil/surfactant/water system by using cyclo‐siloxane, which dissolves silicone resin well. The bicontinuous phase has an oil‐ and water‐continuous microstructure, showing affinity for both aqueous and oily substances. This bicontinuous phase was applied to the development of a novel makeup remover. Determination of remover cap‐ability and fresh skin feel revealed that the makeup could be completely removed and that the amount of oil remaining on skin surface after wash‐off was much less than with previous oil‐based removers. The results of the sensory test also supported the finding that the remover was far superior to conventional products. This makeup remover is the first example of the application of the bicontinuous phase technology to a cosmetic product and clearly seems to provide the best conditions for subsequent skin care, meaning that it is suitable for the first step in the skincare process.     

Identification of enzyme responsible for erythritol utilization and reaction product in yeast Lipomyces starkeyi

We have identified the enzyme responsible for erythritol utilization and its reaction product in the yeast Lipomyces starkeyi CBS 1807. The enzyme, a polyol dehydrogenase requiring NAD+ as a coenzyme, was induced by erythritol in this yeast. We confirmed that the enzyme product was L-erythrulose by MS, NMR, and polarimeter analyses, meaning that we clarified the first step of erythritol utilization in yeasts for the first time. In the case of the oxidative reaction, D-threitol, (2R,3R)-2,3-butanediol, and erythritol were much better substrates than 21 other polyols tested. These three substrates are tetroses and have an R configuration at C-3, and whose third carbon results in easiest oxidation in this enzyme. The research of the substrate specificity in the reductive reaction demonstrated that L-erythrulose and dihydroxyacetone were better substrates, that D-acetoin was inactive and L-erythrose (aldose) was slightly active.