Ecg Holter,Holter Ecg Machine,Bluetooth Ecg Machine,Portable Holter Ecg Machine Changchun Yingwang Times Digital Co., Ltd. , https://www.ccsdsm.com
2. Terms related to humidity measurement
2.1 Water vapour
Also known as water vapor. The gaseous state of water is formed by the vaporization of water or the sublimation of ice.
2.2 Humidity
The content of water vapor in the gas.
2.3 Moisture
The content of water in a liquid or solid.
2.4 Dry gas
Vapor-free gas.
Note: Dry gas with absolutely no water vapor does not exist, and so-called dry gas is only relative.
2.5 Dry air
Does not contain vaporous air.
2.6 Wet gas
A mixture of dry gas and water vapor.
2.7 Wet air
A mixture of dry air and steam.
2.8 Saturated gas
Relative humidity is 100% moisture at a certain temperature.
Note: For saturated moisture at a certain temperature, the dew point value is equal to this temperature value.
2.9 Absorption of water vapour
Water molecules enter the interior of the object through the principle of infiltration.
2.10 Adsorption of water vapour
Water molecules adhere to the surface of the object.
2.11 Desorption of water vapour
The process by which water molecules separate from the surface of an object or the inside of an object. This is the opposite of absorption or adsorption of water vapor.
2.12 Desiccant
The substances used for absorbing water vapor are generally classified into two types: physical absorption and chemical absorption.
2.13 Saturator
A device that turns dry gas into saturated moisture.
Note: When the temperature is above 0°C, it is called water saturator, and when it is below 0°C, it is called ice saturator.
2.14 Mixing ratio
The ratio of the mass of water vapor in the moisture to the mass of dry gas, also known as the mixing ratio.
Note: The humidity reference-hybrid hygrometer is based on the definition of the mass mixture ratio.
(kg?kg-1)
2.15 Absolute humidity
The mass of water vapor in a unit volume of moisture.
(kg?m-3)
2.16 Relative humidity
The ratio of the mole fraction of water vapour in moisture to the percentage of the mole fraction of saturated vapour at the same temperature and pressure, or the ratio of the partial pressure of vapour in moisture to the saturated vapour pressure at the same temperature.
(%RH)
2.17 Water vapour pressure
The pressure at which moisture vapor (volume V, humidity T) exists alone under the same V, T conditions. Also known as steam partial pressure. Water vapor pressure is denoted by e.
2.18 Saturation water vapour pressure
The vapor pressure of water vapor and water (or ice) are in phase equilibrium. Saturated water vapor pressure is represented by es.
Note: The simple calculation formula for the saturated water vapor pressure relative to the water surface:
Relative to the ice surface saturated water vapor pressure simple calculation formula:
In the above formula, t is the water surface or ice surface temperature (oC), ew is the saturated water vapor pressure (value).
2.19 Dew-point temperature
The gas is cooled under isobaric conditions. When the water vapor in the gas condenses into water and reaches a phase equilibrium state, the gas temperature at that time is the dew point temperature of the gas.
2.20 Frost-point temperature
The gas is cooled under isobaric conditions. When the water vapor in the gas condenses into a frost and reaches a phase equilibrium state, the gas temperature at that time is the frost point temperature of the gas.
2.21 Molar ratio of Wet-gas
The ratio of the number of moles of water vapor in moisture to the number of moles of dry gas.
(mol?mol-1)
2.22 Molar fraction of Wet-gas
The ratio of the moles of water vapor in the moisture to the total moles of moisture.
(mol?mol-1)
2.23 Specific humidity
The ratio of the mass of water vapor in moisture to the total mass of moisture.
(kg?kg-1)
2.24 Weight ratio
The mass mix ratio is multiplied by 106.
2.25 Volume ratio
The ratio of the fractional volume of water vapor in the mixed gas to the fractional volume of dry gas is 106 times.
2.26 Molar content of wet-gas The number of moles of water vapor per unit volume of moisture.
(mol?m-3)
2.27 Humidity element
When the humidity of the environment changes, the resistance or capacitance of the element changes accordingly. Such moisture-sensitive resistance and humidity-sensitive capacitance are called humidity sensing elements.
2.28 Hygrometers
The instrument name for measuring the humidity of a gas.
Note: Hygrometers that measure low-humidity gases (usually below the dew point of -20°C) are often referred to as dew-point meters.
2.29 Gravimetric hygrometer
The desiccant is used to completely absorb the water vapor in the gas to be measured. The weight of the desiccant before and after the moisture absorption is measured by a precision balance, and the volume or quality of the gas to be measured is accurately measured. This method is called a gravimetric hygrometer.
Note: The gravimetric hygrometer gives the measured value as the mass mixing ratio. The humidity reference is a gravimetric hygrometer.
2.30 Humidity sensor (transmitter)
Humidity measuring instrument that outputs analog or digital signals.
2.31 Temperature and humidity indicator
The general term for instruments that measure ambient temperature and relative humidity, usually referring to pointer meters.
2.32 hair hygrometer (meter)
The length of the degreased hair is prolonged as the humidity increases, and the change in the length of the hair can be indicated by a mechanical amplification using a pointer to indicate the relative humidity, or by converting the mechanical and electrical quantities to output an electrical signal representing the relative humidity.
2.33 Ordinary psychrometer
A humidity and humidity meter that measures the relative humidity of the environment using the principle of dry and wet bulbs.
Note: This refers especially to dry and wet watches without ventilation.
2.34 Electric ventilation psychrometer
The principle of dry and wet bulbs is used to measure the relative humidity of the environment, with ventilation motor and radiation protection tube.
Note: The electric ventilation and humidity table includes two types of digital display ventilation dry and wet meter and ordinary electric ventilation dry and wet meter without digital display; wet and dry ball thermometer also has two types of glass mercury thermometer and platinum resistance thermometer.
2.35 Dry-bulb temperature
That is, the ambient temperature usually corresponds to the wet bulb temperature of the ventilating and drying table.
2.36 Wet-bulb temperature
The temperature measurement of the wet-bulb thermometer of the ventilated dry-wet meter is wrapped in a special meteorological gauze and kept moist. It is equipped with a radiation protection sleeve. The temperature value measured when the balance is reached under certain ventilation conditions is called the wet-bulb temperature.
Note: Knowing the dry bulb temperature (ie ambient temperature) and wet bulb temperature, the relative humidity value can be calculated by the dry-bulb temperature equation.
2.37 Hysteresis Effect
Humidity sensor p humidity sensor (transmitter) and hygrometer calibration curve in the humidification process and dehydration process calibration curve misalignment.
2.38 Temperature coefficient
Humidity sensor in the same relative humidity environment humidity sensor (transmitter) and hygrometer at different temperature conditions relative humidity drift value and temperature difference ratio.
2.39 Chilled-mirror dew-point hygrometer
Use a thermoelectric cooler to cool the dew point sensor's mirror or surface acoustic wave device so that the water vapor in the gas condenses on the dew-point sensor's mirror surface to expose or defrost. The photoelectric system automatically controls the balance so that the mirror surface is exposed to frost or gas and the gas The water vapor is in a phase equilibrium state, and a platinum resistance thermometer is used to accurately measure the temperature of the dew or frost layer on the mirror surface to obtain the dew point temperature of the gas.
2.40 Humidity generator
The generic term for a device that can generate a constant and known stream of gas or atmosphere under certain conditions.
2.41 Two-pressure humidity generator
Dual-pressure humidity generator is under certain temperature conditions, the gas is saturated in the saturation chamber (instrument), and then in the test chamber decompression and expansion, through the adjustment of the saturation chamber and the test chamber pressure ratio, to obtain different humidity stability Air flow or atmosphere.
2.42 Two-temperature humidity generator
The dual-temperature humidity generator is to saturate a gas at a certain temperature in a saturator (chamber) under a constant pressure condition, and then to increase the temperature in the test chamber, according to the Dalton's partial pressure law and the gas state equation. Calculate the relative humidity of the gas at higher temperatures. By adjusting the temperature of the saturator and the test chamber, it is possible to obtain a flow or atmosphere of different humidity.
2.43 Mixed-flow humidity generator
The split-flow humidity generator mixes the dry gas and the saturated moisture in different proportions under a certain temperature condition to obtain a stable airflow or atmosphere with different humidity.
2.44 Permeation tube humidity generator
Permeability Humidity Generator is based on the principle that organic or polymeric materials are permeable to water. When the permeation area of ​​the material p of the permeation tube (membrane) is effectively equal to the pressure difference between the inside and outside of the tube (membrane) and the flow rate of the carrier gas is fixed, the water penetrates. The rate is only related to temperature.
Note: The penetrating moisture generator can produce several μL/L to 2000 μL/L of constant-humidity gas, which is generally used as a low-range humidity generator.
2.45 Saturated salt humidity generator
The concentration is fixed at a certain temperature. When a saturated salt solution reaches equilibrium within a closed container, the partial pressure of water vapor above the liquid level remains constant, ie the relative humidity is constant. Different relative humidity can be obtained by appropriately selecting different kinds of salts.
2.46 Temperature and humidity chamber
The constant temperature and humidity box is a kind of climatic environment experiment equipment, which can provide a constant temperature and humidity environment. It is generally used to verify or calibrate a large volume of temperature and humidity table or temperature and humidity recorder.
2.47 Karl-fischer moisture meter (Karl-fischer moisture meter)
The Karl Fischer moisture measurement ceremonies use the chemical reaction principle to measure the moisture. The iodine and water in Karl Fischer reagents react with specific effects, obeying a 1:1 quantitative relationship.
Note: Karl Fischer moisture analyzers fall into two categories, the Coulomb method and the volumetric method. Coulometric Moisture Analyzer is suitable for trace moisture measurement. Iodine quantitatively reacts with water through electrolytic reaction. Electrolyte can be used continuously. Volumetric Moisture Analyzer has faster analysis speed, but Karl Fischer reagent needs to be calibrated frequently.
2.48 Infrared moisture meter (Infrared moisture meter)
Based on the principle that water molecules have characteristic absorption bands in the infrared band and can absorb infrared radiation of a certain wavelength, a humidity (moisture) measuring instrument is developed.
Note: The principle of infrared absorption moisture analyzer and infrared absorption moisture analyzer is the same, the difference is only the selected wavelength, and some structural differences.
2.49 Microwave moisture meter (Microwave moisture meter)
The moisture content in the sample has a certain relationship with the dielectric constant. When the microwave passes through the sample to be measured, different dielectric constants cause the microwave to attenuate to different degrees. The moisture content can be determined by the energy loss of the microwave.
2.50 UV moisture meter
Hygrometer developed based on the principle that water molecules absorb ultraviolet radiation.
2.51 Resistive and Capacitive moisture meter
That is, the resistance and capacitance method moisture analyzers convert the resistance value or capacitance value into a measurable quantity according to the quantitative relationship between the moisture content and the resistance value and the capacitance value in the sample, and obtain the moisture in the measured sample by measuring the quantity of electricity. value.
2.52 Enhancement factor
The ratio of the molar content of water vapor in saturated moisture on the water (or ice) surface to the molar content of saturated water vapor at the same temperature.
2.63 Water activity (Equilibrium relative humidity)
For some substances with hygroscopic properties (eg, foods), when the relative humidity values ​​within the substance and its surrounding space reach equilibrium, the relative humidity inside the substance usually becomes the activity of the water.
Note: The activity value of water is a value between 0 and 1, which is dimensionless and not expressed as a value between 0% and 100% relative humidity.
Appendices symbols (in chronological order)
r - mass mixing ratio, also known as mixing ratio (kg?kg-1);
Mv - mass of water vapor (kg);
Ma - the quality of dry gas (kg);
Dv - absolute humidity (kg?m-3);
V - the volume of moisture (m3);
U - Relative Humidity (%RH);
Xv - mole fraction of water vapor (mol?mol-1);
Xsv - mole fraction of saturated water vapor (Pa);
P - the pressure of moisture (Pa);
T - the temperature of moisture (K);
e - water vapor pressure (Pa);
Es - saturated vapor pressure (Pa);
Td - dew point temperature (K or °C);
Tf - frost point temperature (K or °C);
Yv - molar ratio of water vapor (mol?mol-1);
Nv - the number of moles of water vapor (mol);
Na - the number of moles of dry gas (mol);
q - specific humidity (kg?kg-1);
Wr - weight ratio (ppmw);
Vr - volume ratio (ppmv);
Vv - the effective volume of water vapor (m3);
Va - the effective volume of dry gas (m3);
Nv - mole content (mol? m-3);
f - value-added factor.
Humidity Measurement Common Terms Terms and Definitions Technical Specifications
1. SCOPE This technical specification defines common terms and definitions for humidity measurement and is a revising of "Common Measurement Terminology Terms and Definitions" (JJG1001-82).