Analysis of pulse transformer by distributed parameter theory

The pulse responses of magnetically coupled pulse transformers of arbitrary turn ratio n:1 are considered in the framework of a distributed parameter theory. Equivalent circuits for the calculation of pulse risetime and flat-top responses are introduced for inverting- and noninverting-type transformers, respectively. With these equivalent circuits, the pulse risetime responses are calculated more precisely than with the lumped-parameter circuit theory. Measured responses of pulse transformers agree well with the theoretical predictions     

应用于PSTN的IP中继传输及利用度分析

本文分析了在PSTN中引入IP中继传输的基本需求,给出了承载信道IP中继传输的协议设计,并针对IP中继传输的效益性能做了简要的计算分析。结果表明,在典型话务量负载下,通过IP中继传输,带宽利用率能降至约13%。     

A Rational Helmholtz Fundamental Equation of State for Difluoromethane with an Intermolecular Potential Background

A new fundamental thermodynamic equation of state for difluoromethane was developed by considering the intermolecular potential behavior for improving the reliability in the gaseous phase. Reliable second and third virial coefficients are introduced in accordance with the principle of a unified relation of the intermolecular potential energy and the fundamental equation of state. The fundamental equation of state is able to provide reliable thermodynamic properties even at low temperatures or in the region near saturation where precise and accurate experimental data are not available. The estimated uncertainties of calculated properties from the equation of state are 0.07% in density for the liquid phase, 0.1% in pressure for the gaseous phase, 0.35% in pressure for the supercritical region, 0.07% in vapor pressure, 0.2% in saturated-liquid density, 0.7% in saturated-vapor density, 0.01% in speed of sound for the gaseous phase, 0.7% in speed of sound for the liquid phase, and 0.6% in isochoric specific heat for the liquid phase. The equation is valid for temperatures from the triple point to 450 K and pressures up to 72 MPa.     

40 Gbit/s electroabsorption modulators with impedance-controlled electrodes

A novel travelling-wave electroabsorption optical modulator, electrically matched for 50 /spl Omega/ loads of driving circuit drivers, was developed. The scattering parameter of electric reflection (S/sub 11/) from this modulator is less than -20 dB at 20 GHz. It can thus enable a 40 Gbit/s, 2 km SMF transmission with a 0.3 dB penalty at a 1.3 /spl mu/m wavelength.     

Effects of a long-term hypertension control program on stroke incidence and prevalence in a rural community in northeastern Japan

BACKGROUND AND PURPOSE: Although randomized clinical trials have demonstrated the benefit of antihypertensive treatment in preventing stroke, the effectiveness of community-based programs is largely unknown. We investigated long-term community-based prevention activities. METHODS: In rural northeastern Japan, people aged > or = 30 years numbered 3219 in the full intervention community and 1468 in the minimal intervention community in 1965. Systematic blood pressure screening and health education began in 1963. Stroke was registered through 1987. RESULTS: More than 80% of people aged 40 to 69 years were screened in both communities in the 1960s. One community charged for screening services after 1968, whereas the other community intensified intervention; subsequently, screening rates and the follow-up of hypertensive individuals declined in the minimal intervention community, especially in men. In men, stroke incidence declined more (P < 0.001) in the full intervention (42% in the period 1970 to 1975, 53% in the period 1976 to 1981, and 75% in the period 1982 to 1987) than in the minimal intervention community (5% increase, 20% decrease, and 29% decrease, respectively); in women, the stroke incidence declined about 45% to 65% in both communities. Changes in stroke prevalence paralleled those in stroke incidence. Trends in systolic blood pressure levels tend to explain the differential stroke rates in men. CONCLUSIONS: Delivery of hypertension control services through intensive, free, community-wide screening and health education was effective in prevention of stroke for men in a community.     

Prediction of the single-phase turbulent mixing rate between two parallel subchannels using a subchannel geometry factor

This paper presents a simple method for predicting the single-phase turbulent mixing rate between adjacent subchannels in nuclear fuel bundles. In this method, the mixing rate is computed as the sum of the two components of turbulent diffusion and convective transfer. Of these, the turbulent diffusion component is calculated using a newly defined subchannel geometry factor F^* and the mean turbulent diffusivity for each subchannel which is computed from Elder's equation. The convective transfer component is evaluated from a mixing Stanton number correlation obtained empirically in this study. In order to confirm the validity of the proposed method, experimental data on turbulent mixing rate were obtained using a tracer technique under adiabatic conditions with three test channels, each consisting of two subchannels. The range of Reynolds number covered was 5000–66 000. From comparisons of the predicted turbulent mixing rates with the experimental data of other investigators as well as the authors, it has been confirmed that the proposed method can predict the data in a range of gap clearance to rod diameter ratio of 0.02–0.4 within about ±25% for square array bundles and about ±35% for triangular array bundles.     

The radiation therapy of skin cancer of the face

Results of three-year radiotherapy are assessed in 586 patients with skin cancer, with tumors localized on the skin of the face in 484 of these. The results of treatment were found to depend on the histological structure of the tumor and disease stage: 100% cure was attained in patients with basal-cell carcinomas and T1 stage, whereas only 7% of patients with T4 stage were cured; in patients with squamous-cell carcinoma these figures were, respectively, 96.2 and 10%.     

Specific substrates for spectrophotometric determination of penicillin acylase activity

Penicillin acylase substrates suitable for colorimetric determination of the enzyme activity have been tested in this study. The kinetic parameters (Km and kcat) have been elucidated for the following nine substrates: six phenylacetic acid derivatives (p-nitroanilide, p-nitrophenyl ester, p-nitro-m-carboxyanilide, p-nitro-o-carboxyanilide, p-nitro-o-hydroxyanilide, m-nitro-p-carboxyanilide), two D-phenylglycine derivatives (p-nitroanilide, p-nitro-m-carboxyanilide), and also p-nitrophenyl ester of acetic acid (p-nitrophenyl acetate). With the exception of p-nitrophenyl acetate, all the compounds studied are highly specific chromogenic substrates for penicillin acylase, but their reactivity is very variable and kcat/Km values are in a range from 0.8.10(4) to 5.10(6) M(-1).sec(-1).