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Practical methodology for <i>in situ</i> measurement of micro flow rates using laser diode absorption sensors
摘要： A laser diode-based flowmeter based on the infrared absorption method that can measure in situ micro flow rates from 0.2 to 20 ml h?1 was developed. A 1450 nm laser absorbed in water was irradiated to form a heated spot at 0 mm, and the temperature was measured upstream and downstream of the heated spot. The flow rate was measured by the temperature difference obtained by two diode lasers and photodetectors upstream and downstream of the heated spot. We measured the temperature profile of the flow rate by changing the temperature measurement position and the heating laser energy upstream and downstream of the heated spot, and compared the measurements with the simulation results. As the flow rate increased, the temperature profile shifted downstream, and the measured temperature upstream and downstream were analyzed according to the flow rate. The flow measurement range was adjusted according to the temperature measurement position. Increasing the energy of the heating laser also improved the measurement accuracy in the lower flow range. The developed flowmeter was calibrated by the gravimetric method, and the deviation and measurement uncertainty according to the flow rate were obtained. The maximum measurement uncertainty was 6.8% at a 1 ml h?1 flow rate, and the minimum measurement uncertainty was 1.78% at 8 ml h?1. Thus, it was confirmed that the flow rate can be measured through the temperature difference gauged using a simple diode laser set. Using the laser diode-based flowmeter developed in this study, one can measure the flow rate in situ without injecting contaminants, such as particles, for measurements without cutting the piping. In addition, it can be manufactured in a miniaturized form at a low cost, and thus, it can be used for multi-drug infusion analysis, semiconductor process monitoring, etc.
关键词： near infrared absorption,diode laser,micro flow rate,thermal mass flowmeter
更新于2025-11-25 10:30:42
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Soft tissue cutting efficiency by 980?nm laser with carbon-, erbium-, and titanium-doped optothermal fiber converters
摘要： Objectives: The use of near-IR diode lasers for contact soft tissue surgery is attended by a risk of severe thermal damage of surrounding tissues due to the low cutting efficiency of these lasers. To increase the cutting efficiency tips of a near-IR lasers in contact surgery special (converters) which transform laser light to heat are used. The present in vivo study evaluated temperature dynamics and soft tissue cutting efficiency of 980 nm diode laser equipped with standard carbon- and novel erbium- and titanium-doped converters. Materials and Methods: For in vitro treatment on soft tissue (chicken thigh), 980 nm diode laser was used. The radiation was delivered to the tissue by a quartz fiber with a core diameter of 400 ± 5 mm. The carbon-, erbium-, or titanium-doped converters were mounted at the fiber distal end. The converters temperature was measured by IR-sensor integrated into the laser radiation delivery system. The temperature dynamics of each converter during soft tissue treatment was evaluated. The converter was in contact with the soft tissue surface and moved across the surface of soft tissue with a speed of 1, 3, or 6 mm/s. The average power of laser radiation was 0.3, 1.0, or 4.0 W. The collateral thermal damage of treated soft tissues was evaluated using NTBC stain. The width and depth of coagulation and ablation zones of laser wounds was determined. The soft tissue cutting efficiency with different converters was calculated. Results: The cutting efficiency, collateral damage, and converter temperature in contact with soft tissue change depending on the type of converter, the power of laser radiation and the converter movement speed along the temperature tissue (1,980 ± 154 °C), at which a tissue cut takes place, was fixed for Ti-doped converter for laser power of 4.0 W and movement speed of 1 mm/s. Minimal converter temperature (540 ± 30 °C), at which a tissue cut takes place, was fixed for Ti-doped converter for laser power of 1.0 W and movement speed of 6 mm/s. Maximal depth of coagulation (0.72 ± 0.10 mm) was fixed for Ti-doped converter for laser power of 4.0 W and movement speed of 1 mm/s. Minimal depth of coagulation (0.11 ± 0.02 mm) was fixed for C-doped converter for laser power of 0.3 W and movement speed of 3 mm/s. Maximal cutting efficiency (0.57 mm3/W) was fixed for Er-doped converter for laser power of 1.0 W and movement speed of 1 mm/s. Minimal cutting efficiency (0.02 mm3/W) was fixed for C-doped converter for laser power of 4.0 W and movement speed of 6 mm/s. Conclusion: All three studied types of converters can be used for contact surgery of soft tissues by 980 nm diode laser. Er-doped and Ti-doped converters are more resistant to laser heating then C-doped converter, they dissect soft tissue more effectively. This will also expand the potential of everyday routine clinical procedures, making them safer, faster, and easier. These converters can be used in general surgery, plastic surgery, dermatology, angioplasty, dentistry, neurosurgery, etc. Lasers Surg. Med. 9999:1–16, 2018. ? 2018 Wiley Periodicals, Inc.
关键词： soft tissue,coagulation,surgery,efficiency,IR-sensor,diode laser,cutting,converter,fiber
更新于2025-10-24 16:41:07
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Eficacia y seguridad de la ciclofotocoagulación transescleral con micropulsos en el tratamiento del glaucoma
摘要： Objective: To report the results using Micropulse? transscleral cyclophotocoagulation (Iridex) in the treatment of glaucoma. Methods: Retrospective study in adult patients with glaucoma with at least 6 months of follow-up, and only one session of Micropulse?. The same surgical technique was used in all cases. The only laser parameter that could vary was the total treatment duration (in seconds). The remaining parameters were fixed at 2 Watts of power and 0.5 ms (31.3%) of active cycle. Results: A total of 22 eyes of 17 patients with glaucoma of various types and stages were included (mainly congenital and pseudoexfoliation). The mean follow-up time was 7.9 months. The total treatment duration varied from 100 to 180 seconds. Definition of success: 5 mmHg < Intraocular pressure (IOP) < 21 mm Hg and a reduction of ≥ 20% of the baseline value and no addition of oral carbonic anhydrase inhibitors, and no re-operation. The overall success rate was 72.7% in the first month, 54% at 4 months, 41% at 6 months, and 27.3% at final follow-up. Patients with longer treatment durations (180s) achieved better results. The mean reduction in IOP in successful eyes was 36% (from 26.3 to 16.7 mm Hg, SD 4.58, P = .028). No complications were reported. Conclusions: In a heterogeneous population of glaucoma (mostly congenital and pseudoexfoliation types), a low success rate (27.3%) was obtained in the medium-term with a single session of Micropulse?.
关键词： Infrared diode laser,Glaucoma,Micropulse?,Cyclophotocoagulation
更新于2025-09-23 15:23:52
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Equine Surgery || Lasers in Veterinary Surgery
摘要： Surgical lasers facilitate minimally invasive surgery, allow surgical access to otherwise inaccessible areas, and induce tissue interactions, which cannot be obtained with conventional surgical instrumentation. Surgical laser procedures can be performed on an outpatient basis and have eliminated procedures that previously required general anesthesia and hospitalization. Surgeons should be knowledgeable about which procedures can be accomplished with surgical lasers and which are better suited to conventional surgery. This chapter will provide information and guidelines on the use of surgical lasers in equine surgery.
关键词： equine surgery,minimally invasive surgery,carbon dioxide laser,Surgical lasers,neodymium:yttrium-aluminum-garnet laser,holmium:yttrium-aluminum-garnet laser,diode laser
更新于2025-09-23 15:21:01
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Analysis and design of coaxial nozzle with rectangular outlet for high power diode laser in laser metal deposition
摘要： High power diode laser (HPDL) characterized by a wider rectangle beam spot (RBS) with top-hat intensity distribution is particularly applied in laser metal deposition to manufacture large-scale components. In order to design a coaxial nozzle with rectangular outlet to match the RBS of the HPDL, a novel wide-beam coaxial feeding nozzle (WBCFN) outlet is proposed. Based on the gas-powder flow model established in ANSYS FLUENT, the influence of structural parameters of the new coaxial nozzle on the gas flow and powder distribution is investigated. Two quantitative indexes are defined to seek out the optimal designing scheme that minimize the divergences of the powder flow and uniform the powder distribution in transverse and longitudinal directions. And then, the effect and sensitivity of structural parameters on concentration distribution and focal length of powder flow are analyzed. The results indicate that the two indexes increase with the increase of exit width, while the variance of concentration firstly increases and then decreases with the increase of the chamber length and inclination angle. The focal length decreases with the increase of inclination angle. Finally, the optimal solution of designing scheme is obtained through comprehensive analysis, and experiments are carried out to validate the model, which indicates that the designed WBCFN can acquire good morphology and quality of deposition layer for HPDL.
关键词： Wide-beam coaxial feeding nozzle,Laser metal deposition,Discrete phase model,High power diode laser
更新于2025-09-23 15:21:01
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Low Intensity Laser Influence on Orthodontic Movement: A Randomized Clinical and Radiographic Trial
摘要： Introduction: Finding a method to decrease orthodontic treatment time has been a concern for several authors. This study evaluated, clinically and radiographically, the influence of low-level laser therapy on the rate of orthodontic movement and dental tissue integrity. Methods: The sample included 11 individuals with class I malocclusion, requiring extraction of 4 first premolars. Gallium aluminum arsenide diode laser with a wavelength of 780 nm was used once a month during retraction mechanics, to irradiate the maxillary and mandibular canines on one side and compare them with the nonirradiated contralateral side, after spring activation, until canine retraction was completed. This was followed by movement measurement. Periapical radiographs were used to check for possible modifications in the supporting tissues and root surface of the displaced canines. Results: No differences in the rate of tooth movement were found between the irradiated and nonirradiated side on both dental arches. There was no resorption of the root and/or alveolar bone crest, maintaining the integrity of these tissues. Conclusions: Low-level laser therapy did not promote an increment on the rate of tooth movement and did not cause greater root and alveolar bone crest resorption than on the nonirradiated side with the used protocol.
关键词： diode laser,orthodontic tooth movement,Low-level laser therapy
更新于2025-09-23 15:21:01
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Prototype Probe Determining Waveguidea??Gum Contact for a Robot Surgical System
摘要： A probe for cutting soft gum tissue combines a force sensor and a diode laser. In such operations, contact between the tip of the optical waveguide and the soft gum tissue must first be determined. That permits specification of the cutting trajectory in the robot control system. A probe with a diode laser and single-component force sensor is proposed. The errors regarding contact of the laser’s optical waveguide with the soft gum tissue are analyzed.
关键词： soft gum tissue,medical robots,diode laser,force sensor,dental surgery
更新于2025-09-23 15:21:01
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Two dimensional temperature measurement characteristics in pulverized coal combustion field by computed tomography-tunable diode laser absorption spectroscopy
摘要： Two dimensional temperature and concentration distributions are important parameters for pulverized coal combustion used for power plant to understand the combustion field and develop the high efficient combustion technologies. However, it is difficult to measure two dimensional temperature and concentration in pulverized coal combustion field using conventional measurement technologies because pulverized coal combustion produces lots of dust and strong emission from its flame. This paper focused on the application of two dimensional temperature measurement method based on the combination of computed tomography and tunable diode laser absorption spectroscopy using absorption spectra of water vapor at 1388nm and 1343nm for each laser scanning using direct absorption spectroscopy, which show the better characteristics of spatial-temporal resolution, fast response, high sensitivity, self-calibration and optical accessibility. Accuracy of temperature measurement using tunable diode laser absorption spectroscopy was improved by applying the corrected spectroscopic database. Computed tomography reconstruction accuracy of 16 laser-paths configuration was evaluated using sum of squared difference (0.001) and zero-mean normalized cross-correlation (over 0.991), which presented the consistent temperature between assumed and reconstructed distributions. This developed computed tomography-tunable diode laser absorption spectroscopy was successfully applied to pulverized coal flame for two dimensional temperature measurement with 1 ms temporal resolution for time-series two dimensional temperature measurement in the range of 300K-2500K. The rationality was demonstrated by comparison of pulverized coal flame and Methane-Air flame temperature distributions due to the main heat release produced by methane fuel. Its applicability to pulverized coal combustion field will be benefit for optimal operation control and combustion efficiency improvement by combustion organization or new design of combustion system.
关键词： Power plant,Pulverized coal combustion,Computed tomography (CT),Tunable diode laser absorption spectroscopy (TDLAS),Two dimensional temperature measurement
更新于2025-09-23 15:21:01
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Diode laser surgery versus electrocautery in the treatment of inflammatory fibrous hyperplasia: a randomized double-blind clinical trial
摘要： Objectives To compare the efficacy and safety of diode laser and electrocautery techniques for inflammatory fibrous hyperplasia (IFH) removal. Materials and methods In this randomized double-blind clinical trial, 40 individuals were randomly allocated to two groups: group 1 (G1) consisted of 20 individuals assigned to treatment with diode laser and group 2 (G2) consisted of 20 individuals assigned to treatment with electrocautery. The following transoperative parameters were evaluated: bleeding, temperature, and surgical technique parameters (energy deposited on tissue, flow rate, and time of incision). The postoperative parameters evaluated were as follows: pain, functional alterations (chewing, speaking), analgesic medication intake, swelling, healing of the wound area, and patient satisfaction. Results Among the 40 individuals included in the study, four (two in G1 and two in G2) did not complete the entire follow-up. Therefore, 36 individuals (18 in G1 and 18 in G2) participated. Participants in G1 and in G2 had similar demographic characteristics. No difference regarding the trans- or postoperative parameters evaluated was observed between G1 and G2 (p > 0.05). Also, no difference regarding the time for healing was observed between groups. Conclusions Diode laser seems to be as effective and safe as electrocautery when applied under similar conditions for IFH removal. Clinical relevance IFH corresponds to 65% of the lesions observed in denture wearers. This study shows that under similar conditions diode laser is as effective and safe as electrocautery for removal of IFH.
关键词： Cautery,Clinical trial,Hyperplasia,Diode laser
更新于2025-09-23 15:21:01
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The Chicago Water Isotope Spectrometer (ChiWIS-lab): A tunable diode laser spectrometer for chamber-based measurements of water vapor isotopic evolution during cirrus formation
摘要： We describe a new tunable diode laser (TDL) absorption instrument, the Chicago Water Isotope Spectrometer, designed for measurements of vapor-phase water isotopologues in conditions characteristic of the upper troposphere [190–235 K temperature and 2–500 parts per million volume (ppmv) water vapor]. The instrument is primarily targeted for measuring the evolving ratio of HDO/H2O during experiments in the “Aerosol Interaction and Dynamics in the Atmosphere” (AIDA) cloud chamber. The spectrometer scans absorption lines of both H2O and HDO near the 2.64 μm wavelength in a single current sweep, increasing the accuracy of isotopic ratio measurements. At AIDA, the instrument is configured with a 256-m path length White cell for in situ measurements, and effective sensitivity can be augmented by enhancing the HDO content of chamber water vapor by an order of magnitude. The instrument has participated to date in the 2012–2013 IsoCloud campaigns studying isotopic partitioning during the formation of cirrus clouds and in the AquaVIT-II instrument intercomparison campaign. Realized precisions for 1-s measurements during these campaigns were 22 ppbv for H2O and 16 ppbv for HDO, equivalent to relative precisions of less than 0.5% for each species at 8 ppmv water vapor. The 1-s precision of the [HDO]/[H2O] ratio measurement ranged from 1.6‰ to 5.6‰ over the range of experimental conditions. H2O measurements showed agreement with calculated saturation vapor pressure to within 1% in conditions of sublimating ice and agreement with other AIDA instruments (the AIDA SP-APicT reference TDL instrument and an MBW 373LX chilled mirror hygrometer) to within 2.5% and 3.8%, respectively, over conditions suitable for all instruments (temperatures from 204 K to 234 K and H2O content equivalent to 15–700 ppmv at 200 hPa).
关键词： upper troposphere,isotopic ratio measurements,water isotopologues,AIDA cloud chamber,tunable diode laser
更新于2025-09-23 15:21:01