Matches in SemOpenAlex for { <https://semopenalex.org/work/W4244940669> ?p ?o ?g. }
Showing items 1 to 64 of
64
with 100 items per page.
- W4244940669 abstract "By irradiation of the skin with a diode laser the blood flow can be measured using the back scattered light. The majority of the back scattered light is scattered from fixed cells, but a small amount is scattered from moving erythrocytes and is Doppler shifted. The mixed light detected with a photodiode leads directly to a photocurrent proportional to the Doppler signal. A laser Doppler blood flow meter was developed, consisting of a PC-AT (66 MHz), a commercial A/D card (14 bit, 100 kHz) and a special head control card for two laser heads. The heads have a diameter of 35 mm and a height of 15 mm. The heads are fixed to the skin with tape. A DOS-Pascal software program provides the measurement, the calculation of a whole blood flow spectrum and shows the results on the screen with a time resolution of up to 50 Hz. The laser head is connected via 2 m cables with the head control card and contains a diode laser (5 mW, 670, 785 nm) a micro lens, two photodiodes and a pre-amplifier. On the head control card there is the current supply for the laser diodes, also the Doppler signals are band passed (400 Hz to 50 kHz), further amplified and fed into the A/D card. On the A/D card the analog signal is sampled with 100 kHz and digitized with 14 bit resolution. With 256 samples a frequency spectrum (128 channels, 0-50 kHz) is calculated by a FFT, but only the first 100 channels (0-39 kHz) are used to prevent ghosts. The measurements of the Doppler signal of the two laser heads need 5.2 ms and for all software calculations 15 ms are necessary. A quantitative recalculation of a velocity spectrum from the frequency spectrum is only possible if the velocity-, the irradiation-, and scattering-directions are known. In skin the small blood vessels have various directions and because of scattering in skin the irradiation of an erythrocyte can be assumed to be random. With this assumption of a random direction distribution a velocity spectrum can be calculated from the frequency spectrum. A flow spectrum is defined as the product of the velocity and the intensity at this velocity. The flow is defined as the integral over a given region of the flow spectrum. Four independent flow curves can be shown simultaneously on the screen and the frequency region for each flow can be set independently. The flows from low (1-3 mm/s) and high (7-9 mm/s) velocities show a different behavior and give the possibility to distinguish between the flow in the micro capillaries and larger vessels in the skin." @default.
- W4244940669 created "2022-05-12" @default.
- W4244940669 creator A5007445488 @default.
- W4244940669 creator A5043129528 @default.
- W4244940669 date "1996-05-10" @default.
- W4244940669 modified "2023-09-25" @default.
- W4244940669 title "<title>PC-integrated laser Doppler blood flow measurements in skin</title>" @default.
- W4244940669 doi "https://doi.org/10.1117/12.239525" @default.
- W4244940669 hasPublicationYear "1996" @default.
- W4244940669 type Work @default.
- W4244940669 citedByCount "0" @default.
- W4244940669 crossrefType "proceedings-article" @default.
- W4244940669 hasAuthorship W4244940669A5007445488 @default.
- W4244940669 hasAuthorship W4244940669A5043129528 @default.
- W4244940669 hasConcept C120665830 @default.
- W4244940669 hasConcept C121332964 @default.
- W4244940669 hasConcept C126322002 @default.
- W4244940669 hasConcept C1276947 @default.
- W4244940669 hasConcept C142757262 @default.
- W4244940669 hasConcept C158846371 @default.
- W4244940669 hasConcept C192562407 @default.
- W4244940669 hasConcept C199360897 @default.
- W4244940669 hasConcept C2777048131 @default.
- W4244940669 hasConcept C2779843651 @default.
- W4244940669 hasConcept C41008148 @default.
- W4244940669 hasConcept C49040817 @default.
- W4244940669 hasConcept C520434653 @default.
- W4244940669 hasConcept C52305850 @default.
- W4244940669 hasConcept C71924100 @default.
- W4244940669 hasConcept C751236 @default.
- W4244940669 hasConcept C78434282 @default.
- W4244940669 hasConceptScore W4244940669C120665830 @default.
- W4244940669 hasConceptScore W4244940669C121332964 @default.
- W4244940669 hasConceptScore W4244940669C126322002 @default.
- W4244940669 hasConceptScore W4244940669C1276947 @default.
- W4244940669 hasConceptScore W4244940669C142757262 @default.
- W4244940669 hasConceptScore W4244940669C158846371 @default.
- W4244940669 hasConceptScore W4244940669C192562407 @default.
- W4244940669 hasConceptScore W4244940669C199360897 @default.
- W4244940669 hasConceptScore W4244940669C2777048131 @default.
- W4244940669 hasConceptScore W4244940669C2779843651 @default.
- W4244940669 hasConceptScore W4244940669C41008148 @default.
- W4244940669 hasConceptScore W4244940669C49040817 @default.
- W4244940669 hasConceptScore W4244940669C520434653 @default.
- W4244940669 hasConceptScore W4244940669C52305850 @default.
- W4244940669 hasConceptScore W4244940669C71924100 @default.
- W4244940669 hasConceptScore W4244940669C751236 @default.
- W4244940669 hasConceptScore W4244940669C78434282 @default.
- W4244940669 hasLocation W42449406691 @default.
- W4244940669 hasOpenAccess W4244940669 @default.
- W4244940669 hasPrimaryLocation W42449406691 @default.
- W4244940669 hasRelatedWork W1987560605 @default.
- W4244940669 hasRelatedWork W2012717144 @default.
- W4244940669 hasRelatedWork W2063591957 @default.
- W4244940669 hasRelatedWork W2086787788 @default.
- W4244940669 hasRelatedWork W2093833596 @default.
- W4244940669 hasRelatedWork W2155380619 @default.
- W4244940669 hasRelatedWork W2366753127 @default.
- W4244940669 hasRelatedWork W2552576924 @default.
- W4244940669 hasRelatedWork W2802228567 @default.
- W4244940669 hasRelatedWork W1589445462 @default.
- W4244940669 isParatext "false" @default.
- W4244940669 isRetracted "false" @default.
- W4244940669 workType "article" @default.