The present inventive concept relates to a battery-free gas sensor or humidity sensor comprising a metal-organic framework and a method of manufacturing the same. In a photodiode-type battery-free gas sensor or humidity sensor according to the present inventive concept, since photoelectron collection electrodes are formed at certain intervals between P-N junction layers, when gas is adsorbed thereon, the gas can be detected without an extra power source by change of photocurrent. Due to fine pores of the metal-organic framework, gas sensitivity may be increased and stability of catalysts may be improved. When catalysts are not provided, humidity may be detected. Therefore, a system that used the photodiode-type battery-free gas sensor and the photodiode-type battery-free humidity sensor together may be performed humidity correction to accurately measure an amount of a gas.

A gas sensor includes a sensor element having electrode pads, metal terminal members connected to the respective electrode pads, separators, and lead wires connected to the rear ends of the metal terminal members. Each metal terminal member has a forward locking portion and a rear locking portion provided at the forward and rear ends, respectively. The separator is composed of a forward separator and a rear separator connected to each other. The forward separator includes a first locking portion having a rearward-facing surface, and the rear separator includes a second locking portion having a forward-facing surface. The metal terminal member is held between the forward separator and the rear separator in a state in which the forward locking portion is in locking engagement with the rearward-facing surface and the rear locking portion is in locking engagement with the forward-facing surface.

Provided is a capacitive gas sensor. The capacitive gas sensor comprises a sensitive material for adsorbing and desorbing a target gas, an upper electrode surrounding the sensitive material, a lower electrode facing the upper electrode, and a porous structure disposed between the upper electrode and the lower electrode, wherein the capacitance of the sensitive material changes as the sensitive material adsorbs and desorbs the target gas.

A composition ratio estimation device estimates a composition ratio of a content having mixed substances with different boiling points in a tank. The content is retained as a liquid in the tank lower part. The substances are partially floatable as a gas or liquid in a space in the tank upper part. The device includes a reference object disposed in the space, a transmitting-receiving unit that transmits radar waves toward the reference object and the surface of the liquid and receives reflected radar waves, a temperature measuring unit that acquires a level at which a boiling point of a floating substance is reached, a dielectric constant calculating unit that stores in advance a physical distance between the unit and the object and calculates a dielectric constant of a space between the unit and the object, and a composition ratio derivation unit that derives a composition ratio of the liquid.

A gas sensor for detecting a physical and/or chemical value of an analysis gas, a corresponding manufacturing method, and operating method. The gas sensor is based on the principle of a thermal conductivity measurement with the aid of a sensor structure including a double meander structure made up of two resistor lines, as part of a Wheatstone bridge circuit, on a diaphragm of a substrate. The two resistor lines are energized in opposite directions as a function of the detected temperature. The physical and/or chemical value(s) of the analysis gas are/is subsequently determined as a function of the voltages detected at the double meander structure.

Devices and methods for detecting an analyte in a gas involve the use of plasmonic excitation of a nanostructured sensing element that is tuned to absorb at a narrow bandwidth specific for light absorbed by the analyte. The sensing element can be used as a capacitive or inductive element in a circuit.

The present invention provides capacitive gas sensor and manufacturing method thereof in which the capacitive gas sensor comprises: a first electrode; a second electrode; a gas-sensitive dielectric material arranged between the first and the second electrodes to form a gas sensitive capacitor, the gas-sensitive dielectric material has a permittivity that depends on an amount of a gas compound absorbed from the environmental medium; and a dielectric-electrode interfacing material arranged at an interface between the gas-sensitive dielectric material and at least one of the first and second electrodes. The dielectric-electrode interfacing material is adapted to absorb thermally-induced dilatation of the at least one of the first and second electrodes for reducing mechanical stress on the gas-sensitive dielectric material.

A device for determining a measurand, includes a first pattern made from a first conductive material, the first pattern having a first impedance and having a first end and a second end spaced apart from the first end, a second pattern at least arranged between the first end and the second end of the first pattern, being in electrical contact with the first pattern. The second pattern has a second impedance that changes continuously as a function of the measurand, such that the impedance or the inductance of the assembly formed by the first and second patterns changes continuously as a function of the measurand. The device also comprises a means for determining the impedance or the inductance of the assembly formed by the first and second patterns.

Detection and capture of toxic nitrogen oxides (NO.sub.x) is important for emissions control of exhaust gases and general public health. The low power sensor provides direct electrically detection of trace (0.5-5 ppm) NO.sub.2 at relatively low temperatures (50° C.) via changes in the electrical properties of nitrogen-oxide-capture active materials. For example, the high impedance of MOF-74 enables applications requiring a near-zero power sensor or dosimeter, such as for smart industrial systems and the internet of things, with 0.8 mg MOF-74 active material drawing <15 pW for a macroscale sensor 35 mm.sup.2 area.

Embodiments herein relate to systems and methods for utilizing hysteresis as a mechanism of analysis of a sample. A system for analyzing a fluid sample is included having a controller circuit and a chemical sensor element. The chemical sensor element can include one or more discrete binding detectors that can include one or more graphene varactors. The system can include measurement circuitry having an electrical voltage generator configured to generate an applied voltage at a plurality of voltage values to be applied to the one or more graphene varactors. The system can include a measurement circuit having a capacitance sensor configured to measure capacitance of the discrete binding detectors resulting from the applied voltage. The system for analyzing the fluid sample can be configured to measure hysteresis effects related to capacitance versus voltage values obtained from the one or more graphene varactors. Other embodiments are also included herein.