Ngk Insulators, Inc.

Toyota Jidosha Kabushiki Kaisha

International Superconductivity Technology Center

Kawasaki Jukogyo Kabushiki Kaisha

Naoyuki Ogawa

Tomonori Takahashi

Toshihiro Yoshida

Izumi Hirabayashi

Takenobu Sakai

Yuji Katsuda

Shoji Tanaka

Kiyoshi Araki

Hitoshi Sakai

Shinji Ohtsubo

Masaharu Namba

Kozi Nishio

12CaO.7AlOpolycrystal having high conductivity is provided. The conductivity of the 12CaO.7AlOpolycrystal becomes 100 S/cm or more by controlling the nitrogen content in the 12CaO.7AlOpolycrystal within a range of 0.3 to 1.1 wt %, and that the conductivity becomes 150 S/cm or more by controlling the nitrogen content within a range of 0.5 to 0.9 wt %.

Conductive ceramic material and production method thereof

A method for separating p-xylene by separating and recovering only p-xylene from a p-xylene-containing raw material mixture under high-temperature and high-pressure conditions using a zeolite membrane as a separating membrane is provided. The p-xylene partial pressure at the raw material side of the separating membrane is kept at a sufficiently high pressure and the p-xylene partial pressure at the recovery side of the separating membrane is controlled at a pressure which is not higher than the inflection point of p-xylene adsorption curve. This method for separating p-xylene using a zeolite membrane as a separating membrane can secure a sufficient p-xylene permeation amount and has industrial applicability.

Method for separation of p-xylene

An apparatus for sensing low concentration NOx in the atmosphere is disclosed. The apparatus has sensor elements arranged in a flow path of the atmosphere, the resistance of each of said sensor elements varying in response to changes in NOx concentration of the atmosphere; a catalyst arranged between said sensor elements to maintain partial pressures of NO and NO.sub.2 in the atmosphere at an equilibrium state; and measuring means for receiving signals from said sensor elements, one sensor element being contacted with the atmosphere which is not passed through said catalyst and the other sensor element being contacted with the atmosphere which is passed through said catalyst and for determining the concentrations of NO.sub.2 and NO in the atmosphere on the basis of said signals.

Apparatus for sensing low concentration NOx

The disclosed apparatus for sensing low concentration NOx in a measurement gas especially in the atmosphere has at least a sensor element made of an oxide arranged in a flow path of the measurement gas, the resistance of the sensor element varying in response to changes in NOx concentration in the measurement gas. As suitable options of this type of the NOx sensor, there are disclosed a chamber used for an apparatus for sensing low concentration NOx, a gas sensor element and a method of manufacturing the gas sensor element, and an ammonia removing apparatus and an NOx sensor utilizing the ammonia removing apparatus.

Apparatus for sensing low concentration NOx, chamber used for apparatus

A method of measuring a gas concentration for measuring any one of the concentrations of NOx, NO.sub.2, NO, and O.sub.2 by using one or more sensor elements utilizing a metal oxide semiconductor as a sensing element is disclosed. In the method of measuring a gas concentration, any one of the partial pressures of NO.sub.2, NO, and O.sub.2 is calculated on the basis of the following formula (1), and any one of the concentrations of NOx, NO.sub.2, NO, and O.sub.2 is measured on the basis of the calculated partial pressure; ##EQU1## wherein R is resistance and A-H and Q are constant.

Method of measuring gas concentration

A gas sensor for measuring a specific gas component, especially hydrocarbons, in a gas to be measured, including a hydrocarbon prevention filter preferably made of zeolite. An oxygen concentration difference between (1) an oxygen concentration in a gas to be measured from which hydrocarbons are removed by the hydrocarbon prevention filter and further combustible components are removed and (2) a known oxygen concentration or an oxygen concentration in a gas from which only combustible components are removed, is calculated. Once an oxygen amount necessary for a combustion of hydrocarbons is calculated, it is possible to measure a hydrocarbon concentration in a gas to be measured on the basis of the thus calculated oxygen amount.

Gas sensor, method of measuring gas component by utilizing gas sensor,

An NOx sensor has the sensor element made of an oxide, the resistance of which is varied in response to an NOx component in a gas to be measured, and a measuring portion for measuring a resistance variation of the sensor element and for detecting an NOx concentration in the gas to be measured. A catalyst is arranged at an upstream side of a flow of the gas to be measured with respect reach to the sensor element, which makes a partial pressure ratio of NO/NO.sub.2 reach to an equilibrium state and removes a CO component from the gas to be measured. A heater for adjusting a temperature is arranged at a position close to the sensor element, which maintains temperatures of the sensor element and the catalyst constant. An O.sub.2 sensor is arranged at a position close to the sensor element so that the measuring portion can detect accurately the concentration of Nox in the measurement gas by reference to the resistance of the sensor element.

NOx sensor

A rare earth oxide superconducting material represented by REBa.sub.2 2Cu.sub.3 O.sub.y (RE is Y, Gd, Dy, Ito, Er or Yb), comprises oxide grains and at least one element selected from Rh and Pt, uniformly dispersed in the grain in a proportion of 0.01-5% by weight (in terms of element) based on the rare earth oxide superconducting material. The rare earth oxide superconducting material can be produced by a melt processing and gives a high critical current density even in a highly magnetic field.

Rare earth oxide superconducting material and process for producing the

Disclosed are an oxide superconductor, and an optimum process for producing the same. The oxide superconductor comprises a base material phase including an oxide superconducting material, the oxide superconducting material including barium (Ba) at least and being free from grain boundaries, and precipitation phases contained in an amount of 1 to 50% by volume in the base material phase and dotted therein in a manner like islands, the precipitation phases being oxides of a metal selected from the group consisting of silicon (Si), aluminum (Al), zirconium (Zr), magnesium (Mg), titanium (Ti), strontium (Sr), tungsten (W), cobalt (Co) and vanadium (V), and being products of decomposition reaction of the base material phase. In the production process, the constituent materials are treated thermally at a partially melting temperature in order to give the above-described novel structure to the oxide superconductor. Thus, the precipitation phases are dotted in a manner like islands in a sea of the base material phase being free from the grain boundaries, and the precipitation phases work as the pinning centers. Therefore, the oxide superconductor exhibits a high 'Jc' value.

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Nagoya, Japan

Naoyuki Ogawa