An automatic torque ripple compensation system for direct drive motors

A serious problem in motion control is the occurrence of torque ripple. Since a direct drive (DD) motor with a magnet rotor uses a rare-earth magnet, the torque ripple is more serious than that of conventional servomotors. This paper presents an auto-compensation of torque ripple using a software-implemented torque observer. The frequency and amplitude of torque ripple can be obtained in the controller by using the estimated torque from an observer, and the autonomous generation of a compensating current component for a torque ripple is possible. The proposed algorithm has been verified by experiments.     

Stabilization of bioethanol recovery with silicone rubber‐coated ethanol‐permselective silicalite membranes by controlling the pH of acidic feed solution

In order to produce highly concentrated bioethanol by pervaporation using an ethanol‐permselective silicalite membrane, techniques to suppress adsorption of succinic acid, which is a chief by‐product of ethanol fermentation and causes the deterioration in pervaporation performance, onto the silicalite crystals was investigated. The amount adsorbed increased as the pH of the aqueous succinic acid solution decreased. The pervaporation performance also decreased with decreasing pH when the ternary mixtures of ethanol/water/succinic acid were separated. Using silicalite membranes individually coated with two types of silicone rubber, pervaporation performance was significantly improved in the pH range of 5 to 7, when compared with that of non‐coated silicalite membranes in ternary mixtures of ethanol/water/succinic acid. Moreover, when using a silicalite membrane double‐coated with the two types of silicone rubber, pervaporation performance was stabilized at lower pH values. In the separation of bioethanol by pervaporation using the double‐coated silicalite membrane, removal of accumulated substances having an ultraviolet absorption maximum at approximately 260 nm from the fermentation broth proved to be vital for efficient pervaporation. Copyright © 2005 Society of Chemical Industry     

Performance prediction of a hybrid‐excitation synchronous machine with axially arranged excitation poles and permanent‐magnet poles

This paper presents a method of predicting the steady‐state performance of a new hybrid‐excitation synchronous machine (HESM) theoretically. The field pole of this HESM is axially divided into two parts; one is an excitation part and the other a permanent‐magnet (PM) part. A nonlinear equivalent circuit, which can include the saliency of the rotor and the magnetic saturation due to the iron core, is derived. Based on this equivalent circuit, the steady‐state performance of the HESM is calculated, and the results are confirmed through experiments. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(2): 43–49, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20033     

Study on purple pigmentation in five cases with purple urine bag syndrome

We reported five patients with purple urine bag syndrome (PUBS). Four patients had indicanuria, and, in three of them, purple pigmentation was reproduced by inoculating urinary isolates, in the broth with indoxyl sulfate. Klebsiella pneumoniae, Pseudomonas aeruginosa and Enterococcus avium were considered to produce the purple pigment in three patients. However, attempts to reproduce the purple pigment failed in two patients, and one of them did not have indicanuria. These results suggest that indicanuria is not necessarily required for the development of PUBS.     

Effect of Mixing Time on the Lubricating Properties of Magnesium Stearate and the Final Characteristics of the Compressed Tablets

The effect of mixing time on hardness, disintegration time and ejection force in tablettlng of magnesium stearate and lactose granules was studied. The hardness of the tablets decreased with an increase in mixing time of the blends, as previously reported. A semilogarithmic plot of the hardness versus mixing time gave a straight line having a turning point. At the early phase of mixing the hardness was decreasing with a large first-order rate and then continued to decrease with another small first-order rate. The change in disintegration time or ejection force versus mixing time was basically the same as that in the hardness. This type of plot was applicable to the mixing magnesium stearate with not only granular but also powdered materials.     

90-nm process-variation adaptive embedded SRAM modules with power-line-floating write technique

The power consumption of a low-power system-on-a-chip (SoC) has a large impact on the battery life of mobile appliances. General SoCs have large on-chip SRAMs, which consume a large proportion of the whole LSI power. To achieve a low-power SoC, we have developed embedded SRAM modules, which use some low-power SRAM techniques. One technique involves expanding the write margin; another is a power-line-floating write technique, which enables low-voltage write operation. The power-line-floating write technique makes it possible to lower the minimum operating supply voltage by 100 mV. The other techniques involve using a process-variation-adaptive write replica circuit and reducing leakage current. These techniques reduce active power during write operations by 18% and reduce active leakage of the word-line driver by 64%. The prototype SRAM modules achieve 0.8-V operation, and a 512-kb SRAM module achieves 48.4-/spl mu/A active leakage and 7.8-/spl mu/A standby leakage with worst-leakage devices.     

Cisplatin plus oral etoposide in the treatment of patients with advanced small cell lung cancer. Japan Clinical Oncology Group

BACKGROUND: Etoposide is a highly schedule-dependent drug. We investigated combination chemotherapy of oral etoposide and intravenous cisplatin for small cell lung cancer (SCLC). METHODS: Fifty-seven patients with SCLC with extensive disease (ED) or limited disease (LD) with pleural effusion registered in the 21 institutions of the Japan Clinical Oncology Group were treated with oral etoposide 40 mg/m2/d for 21 days and cisplatin 80 mg/m2 on day 1 of every 28-period day. The entry period was between February 1992 and August 1995. The actual percentages of patients treated with etoposide were 93.6, 89.5, 92.3 and 96.9% in the first, second, third and fourth cycles, respectively. RESULTS: Nine patients (15.8%) achieved a complete response resulting in an overall response rate of 82.5% (95% confidence interval, 70.1-91.3%). Leukopenia and thrombocytopenia of grade 3 or 4 were observed in 36 (49.1%) and 8 (14.0%) patients, respectively. Anemia of grade 3 or 4 occurred in 28 (49.1%) patients. Nausea, vomiting, anorexia and alopecia were common adverse events. One patient died of hemoptysis due to grade 4 thrombocytopenia. The mean survival time was 47.0 weeks. CONCLUSIONS: This dose and schedule of administration of etoposide in combination with cisplatin are considered to be clinically active. However, prolonged gastrointestinal toxicity of oral etoposide was a problem in comparison with the standard etoposide platinum regimen given by intravenous administration.     

Supramolecular Nanofibers from Collagen-Mimetic Peptides Bearing Various Aromatic Groups at N-Termini via Hierarchical Self-Assembly

Self-assembly of artificial peptides has been widely studied for constructing nanostructured materials, with numerous potential applications in the nanobiotechnology field. Herein, we report the synthesis and hierarchical self-assembly of collagen-mimetic peptides (CMPs) bearing various aromatic groups at the N-termini, including 2-naphthyl, 1-naphtyl, anthracenyl, and pyrenyl groups, into nanofibers. The CMPs (R-(GPO)_n: n > 4) formed a triple helix structure in water at 4 °C, as confirmed via CD analyses, and their conformations were more stable with increasing hydrophobicity of the terminal aromatic group and peptide chain length. The resulting pre-organized triple helical CMPs showed diverse self-assembly into highly ordered nanofibers, reflecting their slight differences in hydrophobic/hydrophilic balance and configuration of aromatic templates. TEM analysis demonstrated that 2Np-CMP_n (n = 6 and 7) and Py-CMP₆ provided well-developed natural collagen-like nanofibers and An-CMP_n (n = 5–7) self-assembled into rod-like micelle fibers. On the other hand, 2Np-CMP₅ and 1Np-CMP₆ were unable to form nanofibers under the same conditions. Furthermore, the Py-CMP₆ nanofiber was found to encapsulate a guest hydrophobic molecule, Nile red, and exhibited unique emission behavior based on the specific nanostructure. In addition to the ability of CMPs to bind small molecules, their controlled self-assembly enables their versatile utilization in drug delivery and wavelength-conversion nanomaterials.     

New type of tin support for hydroprocessing catalyst

TiN supported molybdenum sulfide catalysts showed much higher activity for cleavage of C-C bonds than oxide supported molybdenum sulfide catalysts, indicating the possibility of a new generation of supports for hydroprocessing catalysts.     

Morphological study by TEM on uniaxially oriented thin films of PET, PEN and their blends

Uniaxially oriented thin films of poly(ethylene terephthalate) (PET), poly(ethylene 2,6-naphthalene dicarboxylate) (PEN) and their blends were prepared by applying shear strain to their respective melts, and the resulting morphologies were studied by transmission electron microscopy. Selected-area electron diffraction of each film revealed well-defined uniaxial orientation of polymer chains in the shearing direction. In the uniaxially oriented thin film of PEN, stacked-lamellar structure with the average long period of 27 nm consisting of a crystalline region about 15 nm thick and an amorphous one about 12 nm thick was found here and there in the dark-field image: PEN-type. On the other hand, stacked-lamellar structure was rarely observed in the case of PET: PET-type. In PET/PEN blends, the morphologies changed from the PET-type to the PEN-type with increasing content of PEN.