National Institute for Materials Science

Kosuke Minami

Genki Yoshikawa

Kota Shiba

Gaku Imamura

Takahiro Nemoto

Yusuke Yamauchi

Norihiro Suzuki

Hamish Hei-Man Yeung

Naoto Takeda

Makito Nakatsu

Hideki Matsuzaka

Mitsuyoshi Ishida

Hisami Kobayashi

Masanori Tohno

Ryo Nakakubo

Masaaki Matoba

An object of the present invention is to make it possible to easily evaluate silage fermentation quality on site or the like. In one embodiment of the present invention, a gas generated from silage is applied to a surface stress sensor, and the amount of either one of organic acids and nitrogen-containing compounds contained in the silage is determined. The surface stress sensor can detect trace components in a gas by a simple device configuration and in simple procedures. Therefore, by utilizing the fact that relationship between the content of these components and the fermentation quality is known, the evaluation of fermentation quality can be easily realized by the above measurement.

Evaluation method and evaluation device for silage fermentation quality

An object of the present invention is to detect ammonia with high sensitivity and high selectivity using a nanomechanical sensor with a structure that is as simple as possible. A method for detecting ammonia according to an embodiment of the present invention comprises supplying a sample gas possibly containing ammonia to a nanomechanical sensor that detects a stress or a displacement using poly(methyl vinyl ether-alt-maleic anhydride) as a material of a receptor layer, and detecting presence or absence of ammonia or a content of ammonia in the sample gas based on an output signal from the nanomechanical sensor, in which the sample gas is a humidified sample gas with controlled relative humidity.

Humidification type highly-sensitive/highly-selective ammonia detection method and detection device using nanomechanical sensor

The present invention suppresses an adverse effect caused when an additional gas such as water vapor is mixed in a sample gas or the like that is subjected to gas measurement. In an embodiment of the present invention, in gas measurement for analyzing sensor output signals obtained by alternately supplying a sample gas and a reference gas to a sensor element while alternately switching between the sample gas and the reference gas, the sample gas and the reference gas pass through a humidity equilibration device partitioned by a water vapor permeable membrane, and then are supplied to the sensor element. As a result, since both gases have substantially the same value of humidity at the time of being supplied to the sensor element, influences of water vapor are substantially cancelled out in signals output from the sensor element by the alternate supply of the sample gas and the reference gas.

Measurement method and measurement device using gas sensor

Provided is a novel material analysis technique using a chemical sensor. By reversing the conventional approach, a material to be measured is provided as a receptor of the chemical sensor, and a response signal of the chemical sensor obtained by supplying a known gas or the like to the chemical sensor is obtained. From the response signal, it is possible to identify and distinguish the receptor material, and to obtain its composition and the like. By analyzing the response signal by means of a statistical or machine learning technique such as principal component analysis, linear discriminant analysis, or a support vector machine, the above-mentioned identification and the like can be performed with high accuracy.

Material analysis method and material analysis apparatus

The present invention provides a method for analyzing a liquid sample that solves a problem of a kinetically slow equilibrium at a liquid-solid interface, the problem occurring when liquid sample analysis is performed with a chemical sensor. In the method for analyzing a liquid sample according to an embodiment of the present invention, a component to be analyzed in a liquid sample is adsorbed on a receptor layer of a chemical sensor, one or more kinds of gases are then supplied to the chemical sensor, and a response thereof is measured. As a result, since a slow equilibrium at a liquid-solid interface is not used, a high-sensitivity measurement can be performed in a short time, and existing findings regarding analysis of gas samples on which much progress in research has been achieved can be used.

Method for analyzing liquid sample and apparatus

A method for cleaning a receptor layer of a surface stress sensor according to an embodiment of the present invention includes, in a surface stress sensor that detects a change in surface stress of a thin film, the change being caused by a receptor layer disposed on a surface of the thin film, causing at least a part of a surface region of the thin film to generate heat or supplying heat to the receptor layer from the outside of the surface stress sensor. This makes it possible to easily perform efficient cleaning of a surface stress sensor such as a sensor that performs detection using a piezoresistor while avoiding structural complications as much as possible.

Method for cleaning receptor layer of surface stress sensor

In an analysis of a fluid component using a nanomechanical sensor covered with a receptor, the same receptor is caused to express different response characteristics. In a measuring system of analyzing a response when a sample gas and a purge gas are supplied to a nanomechanical sensor while switching the sample gas and the purge gas, a gas (external gas) different from both gases is mixed into a gas channel and supplied to the sensor for measurement. Since a response characteristic of a receptor is modulated by mixing of the external gas, the object described above is achieved.

Receptor response modulation method, and measuring device using receptor response modulation

The present invention provides a nanomechanical sensor in which a negative influence of water in a sample on measurement is suppressed. In an embodiment of the present invention, as a receptor material of the nanomechanical sensor, a low-hygroscopic material such as polysulfone, polycaprolactone, poly(vinylidene fluoride), or poly(4-methylstyrene) is used. According to this embodiment, a negative influence, such as saturation of a receptor layer by water in the sample, or masking of an output signal based on trace components by an output signal based on water contained in the sample in a large amount, can be suppressed.

Nanomechanical sensor receptor made of low-hygroscopic material and nanomechanical sensor using the same as receptor

According to improvement of the receptor layer of various sensors of the type for detecting physical parameters (for example, a surface stress sensor, QCM, and SPR), all of high sensitivity, selectivity, and durability are achieved simultaneously. A porous material or a particulate material, e.g., nanoparticles, is used in place of a uniform membrane which has been conventionally used as a receptor layer. Accordingly, the sensitivity can be controlled by changing the membrane thickness of the receptor layer, the selectivity can be controlled by changing a surface modifying group to be fixed on the porous material or particulate material, and the durability can be controlled by changing the composition and surface properties of the porous material or particulate material.

Growing community of inventors

Ibaraki, Japan

Kosuke Minami