Provided are a synchronous fluorescence detector for observing the interface concentration of fluorescent pollutants and application method. The detector comprises a first electric displacement platform, a quartz cuvette, an excitation light path, a collection light path and a second electric displacement platform. The application method comprises the following steps: first exciting fluorescent pollutants by utilizing UV light with specific wavelengths to emit fluorescent light; then collecting fluorescence signals emitted by the excited fluorescent pollutants to the greatest extent by utilizing an UV anti-reflection convex lens combination; and finally, processing the fluorescent signals acquired by a photomultiplier by utilizing a difference method to determine a precise light intensity of a thin layer which is moved at a specific spacing by utilizing the electric displacement platforms so as to determine fugacity distribution of the fluorescent pollutants in the microlayer near an interface.

Process for evaluating the catalytic performance of a porous solid using a vapor diffusion technique, where a probe molecule and a molecule for dead-time determination is injected into a carrier gas that is then contacted with the porous solid in a vessel, where a detector analyzes the peak width and retention time of a probe molecule and the retention time of the molecule for dead-time determination in the gas exiting the vessel.

A method of performing a diffusion test includes clamping a membrane to a body such that a first surface of the membrane is in fluid communication with an interior chamber of the body and a second surface of the membrane is exposed to ambient air, flowing a substance through the ambient air such that at least a portion of the substance lands on the second surface while the membrane is vertically oriented, and determining a concentration of the substance in the interior chamber after some of the substance has diffused through the membrane.

This invention relates to a method for measuring viscosity of a fluid using particle diffusometry (PD). The method finds practical applications in detecting structural and functional changes of a biomolecular composition by comparing the viscosity change as compared with the standard of the biomolecular composition. This method may also find uses in clinical diagnosis and quality control of clinical biological medicines, food and feeds during the process of manufacturing, distribution and consumption.

A method is provided for measuring the viscosity of a fluid sample. The method comprising the steps of: (ii) providing a flow of the fluid sample; (iii) providing a component flow, wherein the component flow is a flow of the fluid sample further comprising a tracer component; (iv) generating a laminar flow of the flow (ii) with the flow (iii) in a diffusion channel, such as a microfluidic diffusion channel (2); (iv) measuring the lateral diffusion of the tracer component across the flows; and (v) determining the viscosity of the fluid from the measured diffusion profile, wherein the size of the tracer component is known or is determined.

A method of determining a relationship between a mutual diffusion co-efficient D.sub.m and the concentration c of a solute within a solvent. The method comprises: obtaining a Taylorgram comprising a plurality of measurements of solute concentration c; and deriving from the Taylorgram a plurality of mutual diffusion coefficient values D.sub.m corresponding with a plurality of different concentrations c of solute in the solvent.

A computer-implemented method for configuring operating conditions for at least one of desalination equipment and fluid injection equipment to be used in a low salinity waterflood on a hydrocarbon-bearing reservoir is provided. The reservoir is penetrable by an injection well and a production well. The method comprises deriving an ion diffusion distance value from: a diffusion coefficient indicative of a rate of diffusion of ions through relatively permeable layers of the reservoir when the low salinity water is present therein; and a residence time value indicative of the time required for the low salinity water to pass from the injection well to the production well through the reservoir; comparing the thickness of the relatively permeable layers to the derived ion diffusion distance value; generating an indication of the effectiveness of performing a low salinity waterflood; and configuring said operating conditions based on the indication of the effectiveness.

The invention provides a method for measuring the diffusion performance of an acid dye in a color paste, comprising preparing a primary paste and placing the primary paste into a transparent cylindrical container; adding a dye to the primary paste formulate a color paste, and flatly and uniformly paving a layer of the color paste on an upper surface of the primary paste; performing constant-temperature treatment at 60-95 C. on the cylindrical container, so that the dye in the color paste on the top of the blank primary paste in the cylindrical container diffuses downwards to the bottom of the cylinder; and sampling the primary paste from a sampling hole, and diluting the sampled primary paste with deionized water. The method of the invention has simple operation steps, reliable and safe experiments, highly stable test data and good reproducibility of results, and high temperature and high pressure are not required herein.

A method for determining the diffusion of one or more components, the method includes the steps of (i) providing a component fluid flow having one or more components; (ii) providing a blank fluid flow; (iii) bringing the flow (i) into contact with the flow (ii) in a large cross section channel, thereby to generate two laminar flows; (iv) permitting the laminar flows generated in (iii) to flow from the large cross section channel into a small cross section channel; measuring the lateral diffusion of the one or more components from the component flow into the blank fluid flow in the small cross section channel. Also provided is a diffusion method having the steps of measuring the lateral diffusion of the one or more components from the component flow into the blank fluid flow at a plurality of diffusion times.

A method of estimating a parameter for fitting a multi-component Taylorgram model to Taylorgram data g(t) is disclosed. The data comprises a multi-component Taylorgram peak or front at t=t.sub.r. The method comprises: evaluating a value of an integration or differential of the data; determining the parameter, based on an analytical expression that includes the value of the integral or differential of the data, the parameter corresponding with a physical property of a sample from which the Taylorgram data was obtained.