Remote sensing of path-averaged raindrop size distributions from microwave scattering measurements

A multichannel microwave propagation experimental system whose frequencies are 1.7 GHz, 11.5 GHz, 34.5 GHz, and 81.8 GHz is introduced in order to measure not only attenuation and phase shift due to rain, but also to infer a path-averaged raindrop size distributionoverline{N(D)}from the measurements, in addition to 11.5 GHz, 34.5 GHz, and 81.8 GHz copolar attenuation, phase variations between the frequencies of 34.5 GHz and 11.5 GHz (with reference to 34.5 GHz) due to heavy rain are measured. These measurements, i.e., propagation constants, constitute a Fredholm integral equation of the first kind with respect tooverline{N(D)}. This equation is solved numerically by several inversion techniques, and the results foroverline{N(D)}> are compared with each other. It is made clear that the remote sensing ofoverline{N(D)}from the measurements of microwave scattering is a useful method.     

Multiple primary malignant neoplasms in female genital organs:--a report of six cases

146 of 226 patients suffering from Hodgkin's disease were submitted to a high voltage therapy in the chest using the method of single fields. In order to be in a position to judge the appearance and the development of a modification of the pulmonary parenchyma induced by radiations, the authors evaluated the data of 69 patients who could be checked up in relatively small intervals during at least one year after the radiotherapy. Dilatations of interpleural and hilar lymphomas or pulmonary infiltrates have to be considered as one of the most important causes of atypical pneumonia and fibrosis induced by radiation. 12 patients out of 35 (i.e. 35,3%) with intrathoracic lymphomatosis granulomatosa presented atypical pneumonias which mostly were not very serious, and four patients (i.e. 11,8%) had fibroses. If the mediastine was irradiated systematically for the purpose of prophylaxis, no pulmonary reaction was observed that could be demonstrated by means of X-rays.     

Induction of DNA double strand breaks in scid cells by carbon ions

The DNA double strand breaks (DSBs) induced by X ray and carbon ion beam irradiation in scid cells were analysed using pulsed-field gel electrophoresis. Scid cells and hybrid cells were ideal to study the DNA DSB repair mechanisms, because their genetic backgrounds were identical except DNA-PK activity. Induction of DNA DSBs was determined after exposure to X rays and carbon beams. DNA DSB repair was by biphasic kinetics with a fast and a slow component. For scid cells only a slow component was observed, whereas the kinetics of DSBs repair was biphasic with a fast and a slow component. It was concluded from the experimental data that the induced DSB rejoining in scid cells was due to the lack of DNA-PK activity.     

A micro active probe device compatible with SOI-CMOS technologies

A surface-micromachined active probe device with built-in electrostatic actuator and on-chip CMOS circuits is described. The device has been fabricated on a silicon-on-insulator (SOI) substrate using a 0.6-μm CMOS-based process containing four polysilicon layers and one metal layer, and its basic functionality has been verified experimentally. A 0.135-μm-thick surface silicon layer of an SOI substrate was used to form cantilever beams. The very thin structures enable a probe to be turned on at a voltage as low as several volts. A stopper structure, used to avoid contact between a deflector electrode and its paired stator electrode, was formed with a small overlap area of approximately 0.05 μm². The small overlap area results in a small adhesion force, approximately 70 nN. An n-p-n junction was exploited as an isolator in the probe. A p-n junction in a released beam had only a 5-pA leakage current at a 9-V reverse bias. In addition, it has been found that electrostatic charging is a major source causing unrestorable postrelease stiction     

Measurments of attenuation and refractive dispersion due to atmospheric water vapor at 80 and 240 GHz

Field line-of-sight propagation experiments were made at 80 and 240 GHz on a horizontal path of 810 m. The measured attenuations showed quadratic dependences on atmospheric water vapor density, and absorptions in excess of theoretical predictions were observed at both frequencies, while the measured refractive dispersion between these two frequencies showed a linear dependence on water vapor density and was in good agreement with theoretical prediction. Liebe's model for water vapor attenuation including empirical continuum absorption is confirmed to be effective for 80 and 240 GHz.     

Aphananthe aspera kernel oil: A rich source of linoleic acid

The seed kernels ofAphananthe aspera Planch. yielded 50.8% of a pale yellow oil. The fatty acid composition determined by gas liquid chromatography was: 5.3% palmitic, 0.1% hexadecenoic, 3.0% stearic, 6.1% oleic, 85.1% linoleic, and 0.4% linolenic acids.     

Modification of cation exchange membrane by grafted poly(4-vinyl-N-methylpyridinium-iodide)

It is well known that cation exchange membranes, having a very thin layer of a cationic polyelectrolyte on the membrane surface, have preferential permselectivity for monovalent cations in a monovelent-divalent cations system. We studied the relationship between preferential permselectivity and molecular structure of the cationic polyelectrolyte. Grafted poly(4-vinyl-N-methylpyridinium-iodide) was used and was compared with poly(4-vinyl-N-methylpyridiniumiodide). The backbone polymers were poly(styrene-co-p-benzylstyrene) and poly(benzyl), onto which 4-vinylpyridine was grafted by anionic polymerization and then quaternized with CH₃I. The grafted poly(4-vinyl-N-methylpyridinium-iodide) is effective in making the cation exchange membrane preferentially permselevtive for Na⁺ - Ca²⁺ system and is more preferable than poly(4-vinyl-N-methylpyridinium-iodide) in terms of electric resistance of the membrane. However, the relationship between the molecular structure of the cationic polyelectrolyte and the durability of the preferential permselectivity is not clear.     

The corrosion behaviour of chromium in hydrogen chloride gas and gas mixtures of hydrogen chloride and oxygen at high temperatures

A kinetic investigation of the CrHClO₂ system at 1 atm was carried out varying the oxygen content from 0 to 75 vol% at 400–800°C by the thermogravimetric method in stagnant gases and by measurements of weight loss and weight of sublimates after corrosion tests in flowing gases. In hydrogen chloride gas the corrosion rate is determined by the rates of formation and evaporation of a CrCl₂ scale: the scale was protective, to some extent, up to 600°C, but rapidly evaporated at still higher temperatures. The addition of oxygen led to suppression of corrosion loss up to about 500°C but to catastrophic corrosion at higher temperatures. The scale formed in the gas mixtures consisted mainly of Cr₂O₃ but vigorous vaporization of CrCl₂ and water occurred at the higher temperatures due to oxy-chlorination.     

Characteristics of ozone generation by a diffuse glow discharge at atmospheric pressure using a double discharge method

In this research, a diffuse glow discharge generated by a double discharge is used to improve the efficiency of ozone generation. In this method, corona discharge occurs in the space between the cathode and the trigger electrode covered by Pyrex glass tubes, set in a groove cut on the cathode. Thus, many initial electrons are generated around the cathode. In the present research, experiments were done in air (O₂/N₂ mixture) at atmospheric pressure and the discharge repetition frequency was 1 Hz for all experiments. The maximum ozone concentration generated was about 150 ppm. The average ozone yield was about 400 g O₃/kWh, much higher than the typical yield of about 100 g O₃/kWh. The efficiency of energy transfer from energy stored in storage capacitor C₁ to the main discharge zone was about 40% to 50%. © 1999 Scripta Technica, Electr Eng Jpn, 127(2): 8–14, 1999