Abstract: A liquid crystal display device having a phase difference plate and a reflector, which is capable of providing a bright display. When the value of the ratio K of the product .DELTA.n1.multidot.d1, where .DELTA.n1 is the optical anisotropy and d1 is the thickness in the vertical direction of the phase difference plate to the product .DELTA.n2.multidot.d2, where .DELTA.n2 is the optical anisotropy and d2 is the thickness of the phase difference plate when inclined at 45.degree. from the vertical direction of the phase difference plate in the direction of the optical axis, is in the range of K.gtoreq.1.20, the optical axis of the phase difference plate is disposed at an angle in the range of from about +30.degree. to about +60.degree. or in the range of from about -30.degree. to about -60.degree. with respect to the direction of observation, where the values of angles are positive when measured clockwise from the observation direction, whereas, when K<1.

Abstract: A liquid crystal display device having a phase difference plate and a reflector, which is capable of providing a bright display. When the value of the ratio K of the product .DELTA.n1.d1, where .DELTA.n1 is the optical anisotropy and d1 is the thickness in the vertical direction of the phase difference plate to the product .DELTA.n2.d2, where .DELTA.n2 is the optical anisotropy and d2 is the thickness of the phase difference plate when inclined at 45.degree. from the vertical direction of the phase difference plate in the direction of the optical axis, is in the range of K.gtoreq.1.20, the optical axis of the phase difference plate is disposed at an angle in the range of from about +30.degree. to about +60.degree. or in the range of from about -30.degree. to about -60.degree. with respect to the direction of observation, where the values of angles are positive when measured clockwise from the observation direction, whereas, when K.gtoreq.1.

Abstract: A solid electrolyte is interposed between a first electrode layer located while in contact with the gas to be measured and a second electrode layer located while in contact with a reference gas. The first electrode layer is covered on its high-temperature portion with a first porous protecting layer and on its low-temperature portion with a second porous protecting layer which is lower in gas permeability than the first porous protecting layer. This electrochemical element can be produced without detriment to the porous protecting layers, e.g., causing them to peel off or crack. In addition, it can be used while any lowering of insulating resistance between the first electrode layer and the associated metal holder, thereby providing an accurate detection of the concentration of a specific gas in the gas to be measured.

Abstract: A liquid crystal display device having a phase difference plate and a reflector, which is capable of providing a bright display. When the value of the ratio K of the product .DELTA.n1.multidot.d1, where .DELTA.n1 is the optical anisotropy and d1 is the thickness in the vertical direction of the phase difference plate to the product .DELTA.n2.multidot.d2, where .DELTA.n2 is the optical anisotropy and d2 is the thickness of the phase difference plate when inclined at 45.degree. from the vertical direction of the phase difference plate in the direction of the optical axis, is in the range of K.gtoreq.1.20, the optical axis of the phase difference plate is disposed at an angle in the range of from about +30.degree. to about +60.degree. or in the range of from about -30.degree. to about -60.degree. with respect to the direction of observation, where the values of angles are positive when measured clockwise from the observation direction, whereas, when K<1.

Abstract: An electrochemical device having an oxygen-ion conductive solid electrolyte body, a plurality of electrodes formed on the solid electrolyte body, an electrically insulating ceramic layer formed on the solid electrolyte body, a heater disposed such that the heater is electrically insulated by the ceramic layer from the solid electrolyte body, and a dc power source electrically connected to the heater for energizing the heater. At least one of the electrodes is electrically connected to a low-potential terminal of the dc power source. A voltage source is connected in a line between the above-indicated at least one electrode and the low-potential terminal of the dc power source, so that a potential of each of the at least one electrode with respect to a potential V1 at a point of connection of the above-indicated line to the low-potential terminal of the dc power source is maintained at a positive value which satisfies a formula, V1.ltoreq.

Abstract: A ceramic heater including a ceramic body and a heater element formed on the ceramic body. The heater element has a heat-generating portion formed of a cermet containing a ceramic material and a metal material which principally consists of at least one noble metal, electrical lead portions formed of a metallic material which principally consists of at least one base metal, or formed of a cermet containing a ceramic material and said metallic material, and connecting portions connecting said heat-generating portion to said electrical lead portions.

Abstract: An NOx sensor having an electrochemical cell having a solid electrolyte body and a first and a second electrode, a portion that permits restricted communication of the first electrode with an external measurement gas space, a catalyst disposed adjacent the first electrode for decomposing NOx, a device for applying a current between the first and second electrodes, a current measuring device for detecting a current flowing between the first and second electrodes, an oxygen partial pressure measuring device for detecting an oxygen partial pressure of the atmosphere surrounding the first electrode, and a control device for calculating the concentration of NOx contained in the measurement gas in the external space, based on a first and a second current value.

Abstract: A gas sensor for dealing with a measurement gas in an external space, including an electrochemical pumping cell having a planar solid electrolyte body, and a first and a second electrode which are disposed on opposite surfaces of the solid electrolyte body. The sensor has a gas-tight ceramic body cooperating with the solid electrolyte body, to define therebetween a thin flat space, such that the first electrode communicates with the thin flat space. The thin flat space extends in a direction parallel to a plane of the planar solid electrolyte body and has a predetermined diffusion resistance to the measurement gas. The sensor further includes a porous structure exposed to the thin flat space in a direction of thickness of the thin flat space. The porous structure is juxtaposed with respect to the first electrode in the direction parallel to the plane of the solid electrolyte body, and maintains the thin flat space in communication with the external space under a predetermined diffusion resistance.

Abstract: An electrochemical device including an electrochemical cell having a first solid electrolyte, and at least one pair of electrodes formed on the first soild electrolyte, and a heating portion having a second solid electrolyte, a first elctrically insulating ceramic layer formed on the second solid electrolyte, and a heater electrically insulated from the second solid electrolyte by the first insulating layer. The device further includes a second electrically insulating ceramic layer interposed between the first and second solid electrolytes, so as to electrically insulate these solid electrolytes from each other, and a protective electrode formed in contact with the second solid electrolyte of heating portion. The protective electrode is electrically connected to at least one of the of electrodes of the electrochemical cell.

Abstract: A gas sensor for dealing with a measurement gas in an external space, having (a) an electrochemical pumping cell including a porous solid electrolyte body, and a first and a second electrode which are disposed on opposite sides of the porous solid electrolyte body, (b) a gas-tight ceramic body cooperating with a porous solid electrolyte body of the electrochemical pumping cell, to define therebetween an internal space, such that the first electrode substantially communicates with the internal space, and (c) a gas-tight solid electrolyte layer formed on or within the porous solid electrolyte body such that the first electrode is substantially entirely overlapped by the gas-tight solid electrolyte layer, as viewed in a direction perpendicular to a plane of the first electrode. The gas-tight solid electrolyte layer is formed to permit a portion of the porous solid electrolyte body to communicate with the internal space in the above-indicated direction.

Abstract: A method of detecting the concentration of a component in gases, by an electrochemical element comprising a pumping cell having a first and a second electrode on a solid electrolyte layer, and a sensing cell comprising a third and a fourth electrode disposed on another solid electrolyte layer, the first and third electrodes being located adjacent to each other, and exposed to the gas to be measured which has been diffused with a predetermined diffusion resistance. A primary pumping current is applied to the pumping cell to control the partial pressure of the component in the atmosphere adjacent to the first and third electrodes. The primary pumping current is controlled so that an electromotive force induced on the sensing cell concides with a predetermined value.

Abstract: An electrochemical sensing element which includes at least one electrochemical cell having a planar solid electrolyte body and a pair of electrodes in contact with the planar solid electrolyte body, and which further includes at least one electrical heater layer which is located on one of opposite sides of the electrochemical cell. The heater layer comprises a heater member having a heat-generating portion in the form of a serpentine or sinuous strip to heat at least a portion of the electrochemical cell at which the electrodes are disposed. The serpentine strip is formed in zig-zag fashion to provide a heating region in which the heat-generating portion is accommodated. The heat-generating portion has a larger cross sectional area at its central parts located in a central portion of the heating region, than at its peripheral parts located adjacent to the periphery of the heating region.

Abstract: In an electrochemical apparatus utilizing an electrochemical cell having a solid-electrolyte and at least one pair of porous electrodes arranged in contact with the solid-electrolyte, wherein one electrode of the pair of electrodes is exposed through a diffusion means having a diffusion resistance with respect to a gas to be measured in a space in which the gas to be measured is present, and an atmosphere near one of the electrodes is controlled by an electrode reaction due to a current flowing through the pair of electrodes, a first branch conductor and a second branch conductor are formed by dividing one of conductors respectively connected to the electrodes, and at least one adjustable first resistive means and at least one second resistive means are respectively formed in the first branch conductor and the second branch conductor.

Abstract: A process for the removal of hydrogen sulfide from a gas which comprises contacting the gas with a solution comprising ferric ions (Fe.sup.3+) and ferrous ions (Fe.sup.2+). The solution further comprises ethylenediamine tetraacetic acid (EDTA) or a salt thereof and triethanolamine (TEA) or a salt thereof. The solution has a pH in the range of from 7 to 9 and a mole ratio of ferric ion to total iron ions in the range of from 0.60 to 0.90 as measured just after the hydrogen sulfide contacts the solution. The process is characterized by high removal of hydrogen sulfide, prevention of side reactions, and the inhibition of the formation of intermediate colloidal sulfur.