975results about How to "The measurement result is accurate" patented technology

The invention discloses a measuring method of biochemical oxygen demand and a BOD sensor and applications. The measuring method comprises the following steps of: constructing a unilocular air cathode no-amboceptor microbial fuel cell, adding a sample into the microbial fuel cell; measuring output voltage generated by the microbial fuel cell and calculating electrical quantity value; and substituting the electrical quantity value into a liner equation and calculating the BOD value and the like. The invention provides the specific BOD sensor and applications thereof for implementing the method; the lowest detection limit of the measuring method is 0.2mg / L, the measuring range of BOD is 5 to 50mg / L, and the relative error with the detection result of a culture method at the temperature of 20 plus or minus 1 DEG C for 5 days is less than 4.0%. The invention has simple and programmable operation process, stable and fast measuring process, can realize online detection, has low cost and is suitable for promotion and application commonly.

The invention belongs to the field of chemistry and is suitable for measuring the harmful elements of lead, arsenic, cadmium, copper and chromium in a eucalyptus oil food additive. The measuring method comprises the following steps of: firstly, quantitatively splitting a sample of the eucalyptus oil food additive and placing the sample into a polytetrafluoroethylene digester of a microwave digestion instrument; secondly, digesting the sample by adding 40-50mL of nitric acid-peroxide into each 10mL of the sample of the eucalyptus oil food additive; thirdly, taking off a sample solution to cool, release pressure and discharge waste gas and adding ultrapure water to 50mL; fourthly, using 4 percent nitric acid to dilute lead, arsenic, cadmium, copper and chromium of a national standard stock solution (GBW) into standard solution mixing liquid with concentrations of 0.00microgram / L, 2.50microgram / L, 5.00microgram / L, 10.00microgram / L, 20.00microgram / L and 30.00microgram / L step by step, measuring ion abundance by using an ICP-MS (Inductively Coupled Plasma-Mass Spectroscopy) instrument, and with the concentrations as traverse coordinate and the ion abundance as longitudinal coordinate, automatically drawing an element calibration curve by a computer; and fifthly, measuring the ion abundance of the lead, the arsenic, the cadmium, the copper and the chromium in the sample solution of the third step and calculating the content of each element.

The invention discloses a method for simultaneously determining harmful elements in iron ore. The method comprises the following steps of: processing a sample through microwave digestion; under optimized instrument working conditions, drawing a standard curve by a standard addition method to correct the matrix effect; and simultaneously determining the harmful elements including sodium, potassium, lead and zinc in the iron ore by use of an inductive coupling plasma mass spectrometer. Through the invention, the problems of complicated operation and processing steps, low sensitivity, low stability, poor reproducibility and the like in the former determining process are solved; and the method disclosed by the invention has the characteristics of fast determination, high sensitivity and accurate result, and is favorable for environmental protection and human health.

The invention discloses an air chamber for automatically measuring soil respiration, which belongs to the field of ecological research. The air chamber for automatic measurement of soil respiration is composed of an automatic opening device, a base, a measuring chamber and the like. It is driven by a small DC motor placed on the base to realize timing opening and closing during measurement. The measurement chamber consists of a hollow shell, which is divided into upper and lower parts. A temperature probe can be installed in the top center of the upper part of the shell to measure the temperature in the gas chamber. The two sides of the top inside the shell are provided with ventilation ports that communicate with the infrared gas analyzer. The upper part of the shell is equipped with a copper tube with holes; the lower part of the shell is buried in the soil, and the airtightness is realized by the plastic rubber ring when the upper and lower shells are closed; the air chamber for automatic measurement of soil respiration in the present invention can be used for infrared gas analysis. The instrument provides an analytical gas source to calculate the soil respiration rate; it can quickly provide multi-point measurements.

The invention relates to a method of mensurating steel residual stress using X rays, comprising: (1) taking a galvanized sheet, polishing smooth surface layers; taking saturated NaCl aqueous solution as electrolyte, using measured components as anode corrosion ends, using galvanized sheet iron as a cathode, eroding by DC constant pressure, corrosion current being 7-8 A; (2) after corrosion cleavage, mensurating residual stress on vertical direction of welding using X rays, then correcting residual stress measurement value after cleavage using single side cleavage measurement stress value correction method, namely obtaining steel residual stress. According to the inventive method to measurate the steel residual stress, novel additional stress is not increased by electrolytic corrosion cleavage, also measurement result along heavy gauge workpieces is obtained, measurement result is simple, device cost is low.

The invention discloses a method for detecting the content of nicotine in smoke of an electronic cigarette. The detection method comprises the following steps: (1) preparing an extracting agent; (2) preparing a standard series solution of the nicotine; (3) connecting a Cambridge filter and an absorption bottle with a smoking machine in series and capturing the smoke of the electronic cigarette; putting the Cambridge filter for capturing the smoke and absorption liquid into a tapered bottle and carrying out vibration extraction; (4) moving away an extracting liquid filtering membrane and analyzing filter liquid by using a gas chromatographic method; and (5) drawing a standard curve and calculating the content of the nicotine in the smoke of the electronic cigarette. The method disclosed by the invention has the advantages of high sensitivity, good selectivity, simplicity in operation and high repeatability, and can realize the accurate quantitative analysis of the nicotine in the electronic cigarette.

The invention discloses a method and a device for measuring multi-channel ultrasonic flow-. Transducers which are twice as many as sound channels are mounted on a pipe section; every two transducers are connected with each other to form a sound channel; included angle of the sound channels and an axial line of the pipe section ranges from 15 to 75 degrees; a pressure sensor is placed at the front end of the pipe section; distances from the pressure sensor to the centers in the axle directions of all sound channels are the same; the sound channels corresponding to the transducers are divided into chordwise sound channels and radial sound channels; three or more than three chordwise sound channels are projected onto a cross section in the axial direction as a polygon. According to real-time detection of flow field pressure through the pressure sensor, a variance value and an initial value of the flow field pressure in one cycle are compared, and further time interval of flow measurement is increased or reduced, as a result, real-time adjustment of multi-channel measurement time interval is realized, and the method and the device are specially suitable for occasions of violent change of the flow field. Each sound channel comprises a radial sound channel and chordwise sound channels; and when obtained two speeds are compared, whether current state of the flow field is laminar flow or turbulent flow can be judged.