Siemens Aktiengesellschaft

Bernhard Montag

Walter Gumbrecht

Heinrich Opitz

Wolfgang Schelter

Gerd Urban

Heinrich Kimmel

Gert Mages

Wilfried Turk

Reinhard Kress

Peter Hobel

Heinrich Optiz

An electrochemical sensor is provided on a substrate whereby a precious metal layer is arranged in an inner region under an electrolyte layer that is surrounded by a polyimide structure. A hydrophobic layer is surrounded by an outer polyimide structure and further is located on top of the electrolyte layer and extends laterally beyond the electrolyte layer. A lead for electrical connection of the precious metal layer extends under the hydrophobic layer laterally from the electrolyte layer is sealed from the hydrophobic layer by a protective layer. The protective layer prevents the penetration of analysis fluid into the gap between the hydrophobic layer and the surrounding polyimide structure into the inner region of the sensor. The material of the protective layer is preferably a double layer of PECVD oxide and PECVD nitride.

Electrochemical sensor

A planar reference electrode for chemical sensors, which are able to be supplied with a measuring fluid and a calibrating fluid. The planar reference electrode has the following components: an internal reference element situated on a flat substrate; a layer covering the substrate in the vicinity of the internal reference element and consisting of a structured polymer and having at least one trench, which serves as a diffusion channel and extends in the lateral direction from the internal reference element to a region that comes in contact with the measuring fluid or calibrating fluid to be supplied to the chemical sensor, where the diffusion in the diffusion channel is determined by the channel geometry and/or by a diffusion layer; and a covering which seals off the trench.

Reference electrode

The present invention is directed to a chemically sensitive component including an optical filter that reversibly changes color or transparency in response to a gas or vapor to be determined or detected. The optical filter comprises a mixture of a basic or acid color former or dye of the triphenyl methane system and a complementary acid or basic compound which may be embedded in a matrix and/or applied as a coating to a carrier. The optical filter's change in color or transparency can be measured photoelectronically, e.g., with a luminescent diode as a light source and a photodiode or a phototransistor as a light detector.

Chemically sensitive component

A measuring canal is provided which is connected to a catheter. The canal includes a measuring sensor and a reference sensor. The catheter includes several lumens that have a common opening to the liquid measuring medium. The flow direction of an infusion solution at the opening is reversible. A second lumen of the catheter is connected to the measuring canal which is provided with at least one measuring sensor and with at least one reference sensor as well as with a device for setting the outflow of the apparatus to a predetermined velocity. The flow of an infusion fluid and the liquid medium alternates in such a fashion that during a first time interval the measuring sensor is coupled to the liquid medium and the reference sensor is coupled to the infusion solution. In a second interval the situation is reversed so that the original measuring sensor is coupled to the infusion solution and the original reference sensor is connected to the liquid medium. The unique arrangement is effective for blood examination. Drift problems and toxicity problems cannot occur and no electrochemical reference electrode is required.

Apparatus and method for the examination of a liquid medium

The present invention is directed to an optical filter that includes a mixture of at least one basic or acid color former or dye, preferably being a triphenyl methane system and at least one complementary acid or basic compound. The mixture reversibly changes color in response to a gas or vapor. The mixture may be embedded in a matrix substance and/or may be applied to a carrier. The color change may be measured photo-electrically.

Optical filter with reversible color change

The invention relates to a method and apparatus for heat exchange, especially for cooling at solid surfaces. At the solid surfaces, a locally uniform convective heat exchange is achieved. According to the invention, a sink flow is superimposed on a circular flow of a fluid in a flow chamber (1) at a surface of a heat-conducting solid wall (9) by means of a distributor, forming a vortex sink flow. The heat exchange surface of the component (9) to be cooled is at the same time the base plate (8) of a flow chamber (1).

Method and apparatus for heat exchange at solid surfaces

For the recording of local boundary-layer flow-line directions in liquid media by means of a photographic layer,

Method for recording local boundary-layer flow-line directions in liquid

The invention relates to a method for making visible by photochemical means residual moisture distributions in photographic wet film layers subjected to a gas flow. According to the invention, a film diffusely pre-exposed is immersed in an aqueous swelling agent solution which contains either (a) a reducing agent or (b) an alkali. After being exposed to the air stream, the invisible residual moisture profile is immersed in an alcoholic solution of either (a) an alkali or (b) a reducing agent. The half-tone image produced serves for determining stationary local boundary layer thickness distributions, wall shearing stresses, material transfer coefficients and heat transfer coefficients.

Method for making visible residual moisture distributions in

For making families of steady-state heat transfer coefficient curves visible, the invisible residual moisture profile obtained by exposing a moisture photogelatin layer to a gas is immersed, in daylight, in a soluble organic sulfur compound, particularly thioacetamide, and is converted into a silver sulfide line photogram. The method is used, for example, for making visible families of steady-state heat transfer coefficient curves on forced air-cooled electronic assemblies.

Method of making families of steady-state heat transfer coefficient

Stationary heat transfer coefficient fields are made visible by applying a swelled photographic film (original wet film) in daylight to the article to be exposed to the flow. The wet film obtained after it is exposed to a gas flow and removed from the article, is squeezed onto an unexposed dry photographic film. The separated wet copy (latent image) is seeded with reactive gas (H.sub.2 S) to make the moisture profile visible, and is developed into a wet-copy photogram (black-and-white picture), the sharp contours of which (line equidensities, isohumids) can optionally be translated into colors, corresponding to the stationary mass transfer distribution, and with which definite heat transfer coefficients can thereby be correlated.

Method for making stationary heat transfer coefficient fields visible by

For developing residual-moisture photographs according to the wet-film technique, a pre-treatment with a first solution of about 5% ethanolic NaOH is performed first at about 13.degree. C. After the alkali exchange, the exposed film passes through a bath at a bath temperature of 50.degree. C. with a hydroquinone-containing photographic developer. This 'Two-bath wet developing method' takes place in daylight. The developed, fixed, rinsed and dried film can be evaluated directly.

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Forchheim, Germany

Bernhard Montag