A modified power control scheme for remedying the effects of traffic nonuniformity in LEO satellite communications systems

It has been shown in our previous studies that the geographical traffic nonuniformity considerably affects the performance of the low earth orbit satellite communications systems. In this paper, a new scheme for improving the throughput characteristics of these systems at nonuniform traffic distribution is proposed. In this method, some parts of the users under the satellite which is flying over the area with high traffic load are assigned to its neighbor satellites with lower transmitting power levels. It is shown that the method equalizes the traffic loads of the satellites to some degree and, hence, can improve the throughput characteristics of the system.     

Effect of water‐miscible solvents on the organic solvent‐resistant tyrosinase from Streptomyces sp. REN‐21

The effect of various water‐miscible organic solvents (ethanol, methanol, acetone, acetonitrile, N,N‐dimethylformamide (DMF) and dimethylsulfoxide (DMSO)) on the kinetics of 4‐tert‐butylcatechol (tBC) oxidation in the presence of different samples of organic solvent‐resistant tyrosinase (OSRT) has been studied. In contrast to mushroom tyrosinase the enzyme shows a high relative stability in solutions of organic solvents and increased activity toward the bulky and hydrophobic substrate, tBC, in respect to catechol. Rates of the studied OSRT‐catalyzed reactions are however reduced by the presence of organic solvents and for all studied samples of OSRT decrease exponentially with the content of an organic solvent. The effect has been satisfactorily described by the effect of organic solvents on the thermodynamic activity of tBC. The correlation of the inhibition parameters with the hydrophobicity of a particular solvent (log P), its intrinsic molar volume, V_i, and the Dimroth–Reichardt parameter, E_T(30), are shown. The results allow also the prediction of OSRT activity in aqueous solutions of water‐miscible organic solvents. Copyright © 2003 Society of Chemical Industry     

Novel three‐phase current‐regulated digital PWM and its behavioral analysis

There have been various studies of PWM algorithms for a three‐phase voltage‐source AC/DC power converter since the analog modulation scheme based on a triangular carrier wave was proposed in the 1960s. The PWM algorithm can be considered the heart of electronic power conversion. With progress in digital technology, there is an increasing need for gate signals to be generated directly by digital ICs, such as MPU, DSP, or FPGA/CPLD. This paper analyzes quantitatively the precision of current control of digital PWM taking account of both the sampling period and the delay time (the latter is inevitably accompanied by a digital procedure). The delay time is shown to have a double effect on the current error. In addition, the paper theoretically derives the conditions for digital PWM to meet the PPCR (Pulse Polarity Consistency Rule, that is, the next gate command moves only to the adjacent ones or commands). So far as the authors know, no paper has presented the mathematical requirements for PPCR taking account of the effect of the delay time of digital PWM. The derived theoretical results are summarized as digital PWM design criteria for a three‐phase PWM converter in order to facilitate practical implementation of the theory, guaranteeing PPCR behavior as well as quantitative accuracy of current regulation. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(2): 62–77, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10330     

The Effect of Barley Adjuncts on Free Amino Nitrogen Contents in Wort

Free amino nitrogen (FAN) and other low‐molecular‐weight nitrogen compounds (LNC) are highly important as nutrients for yeast. Many different types of low‐malt beer exist around the world, some of which are produced with barley as an adjunct. In these cases, inhibitors contained in barley are known to influence the amount of LNC in wort. Accordingly, it is important to investigate which proteinase class is key in producing these compounds. By investigating the relationship between the FAN contained in wort produced from malt and barley (barley adjunct wort) and malt proteinase activity, it was found that cysteine proteinase and 1,10‐orthophenanthroline (O‐Phen)‐inhibitable metallo proteinases had a significant correlation to the barley adjunct wort FAN levels. In addition, the relationship between malting conditions and these proteinase activities was investigated and the conditions defined for maximal production of proteinases as follows: steeping degree, 50%; germination temperature, 12°C; germination days, 6 days; water spray, 3 times and concentration of gibberellic acid, 10 mg/kg (barley).     

A case of free jejunal graft for anastomotic recurrence after subtotal esophagectomy

A case of anastomotic recurrence after a radical operation for thoracic esophageal carcinoma is presented. A 68-year-old male was treated by subtotal esophagectomy and esophagogastrostomy through retrosternal route. One year after the operation he experienced dysphagia and anastomotic recurrence was detected by an upper gastrointestinal series and fiberscopy. He was admitted to our hospital for radiation therapy. The response was poor and dysphagia wasn't disappeared after radiation therapy at a dose of 10,200 rad. He was consulted to our surgical department for operative therapy. Cervical esophagectomy, partial resection of gastric tube and free jejunal transplantation for the reconstruction were performed. He had been eating anything of food after the operation.     

Backscattering coefficients of H,D, and He ions from solids

Experimental data on the number-backscattering coefficient R_N, the energy-backscattering coefficient R_E, and the mean fractional energy r_E of backscattered particles are tabulated for H, D, and He ions normally incident on elemental solids. References through 1981 are covered. The dependence of R_N and R_E on incident energy is shown graphically for energies from about 10 eV to 100 keV by plotting the experimental data and the empirical formulas of Tabata et al. Graphs are provided for 36 elemental targets of atomic numbers from 6 to 92.     

CO2 decomposition with oxygen-deficient Mn(II) ferrite

An oxygen-deficient Mn(II) ferrite (Mn_0.97Fe_2.02O_3.92) was synthesized and its reactivity to reduce CO₂ gas into carbon was studied at 300°C. The oxygen-deficient Mn(II) ferrite was obtained by flowing H₂ gas through Mn(II) ferrite with a nearly stoichiometric composition of Mn_0.97Fe_2.02O_4.00 at 300° C. The lattice constant of the oxygen-deficient Mn(II) ferrite (0.8505nm) is larger than that of the Mn(II) ferrite with a nearly stoichiometric composition (0.8498nm). The chemical composition of the Mn(II) ferrite changed from Mn_0.97Fe_2.02O_4.00 to Mn_0.97Fe_2.02O_3.92 during the H₂ reduction process, indicating that the oxygen is deficient in the spinel structure of the Mn(II) ferrite. This was confirmed by Mössbauer spectroscopy and X-ray diffractometry. The efficiency of CO₂ decomposition into carbon at 300°C with the oxygen-deficient Mn(II) ferrite was much lower by about 10⁵ than that of oxygen-deficient magnetite. This is considered to be due to the difference in electron conductivity between Mn(II) ferrite and magnetite, which determines the reductivity for CO₂ into carbon by donation of an electron at the adsorption site.     

护毛法回收的猪毛通过爆发性膨胀处理的溶解性

本文报导了通过爆发性膨胀增加猪毛溶解度的方法,从而使得保毛脱毛法所回收的猪毛能够得到更有效的利用。     

A note on the resistance to brittle fracture in various ceramic materials

The square of the ratio of the abraded bending strength, _d, to the unabraded bending strength, , is proposed as a measure of the resistance to crack propagation in ceramic materials. Data for various porcelains, glass-ceramics, and glasses showed that _d is essentially constant and that (_d/)² decreased rapidly with increase of the unabraded strength.