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CALIPSO lidar calibration at 1064 nm: version 4 algorithm
摘要： Radiometric calibration of space-based elastic backscatter lidars is accomplished by comparing the measured backscatter signals to theoretically expected signals computed for some well-characterized calibration target. For any given system and wavelength, the choice of calibration target is dictated by several considerations, including signal-to-noise ratio (SNR) and target availability. This paper describes the newly implemented procedures used to calibrate the 1064 nm measurements acquired by CALIOP (i.e., the Cloud-Aerosol Lidar with Orthogonal Polarization), the two-wavelength (532 and 1064 nm) elastic backscatter lidar currently flying on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission. CALIOP’s 532 nm channel is accurately calibrated by normalizing the molecular backscatter from the uppermost aerosol-free altitudes of the CALIOP measurement region to molecular model data obtained from NASA’s Global Modeling and Assimilation Office. However, because CALIOP’s SNR for molecular backscatter measurements is prohibitively lower at 1064 nm than at 532 nm, the direct high-altitude molecular normalization method is not a viable option at 1064 nm. Instead, CALIOP’s 1064 nm channel is calibrated relative to the 532 nm channel using the backscatter from a carefully selected subset of cirrus cloud measurements. In this paper we deliver a full account of the revised 1064 nm calibration algorithms implemented for the version 4.1 (V4) release of the CALIPSO lidar data products, with particular emphases on the physical basis for the selection of “calibration quality” cirrus clouds and on the new averaging scheme required to characterize intra-orbit calibration variability. The V4 procedures introduce latitudinally varying changes in the 1064 nm calibration coefficients of 25 % or more, relative to previous data releases, and are shown to substantially improve the accuracy of the V4 1064 nm attenuated backscatter coefficients. By evaluating calibration coefficients derived using both water clouds and ocean surfaces as alternate calibration targets, and through comparisons to independent, collocated measurements made by airborne high spectral resolution lidar, we conclude that the CALIOP V4 1064 nm calibration coefficients are accurate to within 3 %.
关键词： calibration,lidar,CALIPSO,version 4 algorithm,cirrus clouds,1064 nm
更新于2025-09-23 15:22:29
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Thermal coagulum formation and hemostasis during repeated multipulse Nd:YAG laser treatment of cutaneous vascular lesions: animal experiment study
摘要： Laser therapy has been widely used to treat port-wine stain (PWS) and other cutaneous vascular lesions via selective photothermolysis. High incident laser fluence is always prohibited in clinic to prevent the thermal damage in normal skin tissue, leading to insufficient energy deposition on the target blood vessel and incomplete clearance of PWS lesion. In this study, repeated multipulse laser (RMPL) irradiation was proposed to induce acute thermal damage to target blood vessels with low incident fluence (40 J/cm2 for 1064-nm Nd:YAG laser). The feasibility of the method was investigated using animal models. Repeated multipulse irradiation cycles with 10-min intervals were performed in RMPL. A hamster dorsal skin chamber model with a visualization system was constructed to investigate the instant generation of thermal coagulum and relevant hemostasis by thrombus formation during and after irradiation under 1064 nm Nd:YAG single multipulse laser (SMPL) and RMPL irradiation. The diameter of the target blood vessel and the size of thermal coagula were measured before and after laser irradiation. The reflectance spectra of the dorsal skin were measured by a reflectance spectrometer during RMPL. Stasis thermal coagula that clogged the vessel lumen were generated during SMPL irradiation with low incident fluence. However, there was no acute thermal damage of blood vessels. Reflectance spectra measurement showed that the generation of thermal coagula and subsequent thrombus formation increases blood absorption by more than 10% within the first 10 min after laser irradiation. Acute vessel thermal damage could be induced in the target blood vessel by RMPL with low incident fluence of 40 J/cm2. Compared with our previous SMPL study, nearly 30% reduction in incident laser fluence was achieved by RMPL. Low fluence RMPL may be a promising approach to improve the therapeutic outcome for patients with cutaneous vascular lesions by improving energy deposition on the target blood vessel.
关键词： Thermal coagula,1064-nm Nd:YAG laser,Port-wine stain,Repeated multiple pulse laser irradiation,Thrombus formation
更新于2025-09-23 15:19:57
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Influence of surface treatment with infrared nanosecond laser on adhesion performance of adhesion-bonded carbon fiber/epoxy composite
摘要： The surface treatment of carbon fiber/epoxy composites with a pulsed infrared (1064 nm wavelength) nanosecond (7 ns pulse duration) laser has been investigated. It is found that single 1064 nm laser pulse can remove the polymer matrix from composite surface to expose the carbon fibers by expansion of the pyrolysis gas resulting from laser-induced polymer degradation. The influences of laser power density and scan strategy on matrix removal process have been studied. The bonding strength of laser processed, adhesion-bonded CFRP (carbon fiber reinforced plastic) increase with lower matrix residues on the fibers and a linear relation is found. The adhesion-bonding strength of CFRP surfaces, tested by lap-joint shear test, exceeds the strength measured for untreated and abrasion treated (SiC paper) samples. The main origin of fiber damage of the laser-treated surface is mechanical fracture rather than thermal damage as found by laser scanning confocal microscope and scanning electron microscope. The characteristic morphologies and failure modes of shear-tested surfaces are analyzed. The obvious improvement of adhesive strength is achieved by the laser-treated surfaces attributed to matrix removal and carbon fibers protruding. A 1 D model is established to describe temperature and internal gas pressure of the irradiated surface. The new laser treatment method needs less laser energy and low pulse numbers and prove the way to an efficient, low-cost surface treatment for preparation of high quality adhesion bonded CFRP components.
关键词： matrix removal,adhesion strength,1064 nm laser,Carbon fiber/epoxy composite
更新于2025-09-19 17:13:59
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Different Numbers of Long-Pulse 1064-nm Nd-YAG Laser Treatments for Onychomycosis: A Pilot Study
摘要： Purpose. To examine the benefits of different numbers of 1064-nm Nd-YAG laser treatments in patients with onychomycosis. Methods. This was a pilot study of patients with onychomycosis who were divided into three groups: four treatment sessions (group A), eight sessions (group B), and 12 sessions (group C). Only infected nails of degrees II–III (Scoring Clinical Index for Onychomycosis) were included. Treatment was given once a week using a long-pulse Nd-YAG 1064-nm laser. Patients were followed at 8, 16, and 24 weeks after the first treatment. Side effects were recorded. Results. Treatments were completed for 442 nails in 102 patients. The efficacy rates at 8, 16, and 24 weeks were 35.5%, 38.7%, and 37.4% for group A; 31.4%, 41.7%, and 44.0% for group B; and 27.7%, 50.0%, and 55.4% for group C, respectively. There was a significant difference in the efficacy rate at 24 weeks (?? = 0.016) between groups A and C, but not for groups A vs. B, or for groups B vs. C. No difference in the efficacy rate at 8 or 16 weeks was observed among the three groups. In all three groups, the efficacy was better for degree II nails than for degree III nails (all ?? < 0.05). No side effects occurred. Conclusions. The 1064-nm Nd-YAG laser had clinical benefits against onychomycosis. Higher numbers of treatments provided better long-term (24-week) benefits, but had no impact on the short-term outcomes. The efficacy of laser treatment on degree II onychomycosis was better than for degree III.
关键词： side effects,1064-nm Nd-YAG laser,treatment sessions,efficacy,onychomycosis
更新于2025-09-19 17:13:59
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Laser Therapy for the Treatment of Onychomycosis: Best Evidence Based Practice or Not?
摘要： Onychomycosis is a very common condition that accounts for 50% of all nail pathologies. Currently 2–5% of the world population suffers from this disorder. It is primarily caused by dermatophytes, but the infection can also be caused by yeasts and non-dermatophyte moulds. Onychomycosis is a therapeutic challenge and recently there has been an increase in resistance to oral and topical antifungal agents, leading to 20–25% relapse and/or reinfection rate. During the past 5 years, the emergence of laser therapy has been the topic of discussion as a newer, safer modality of treatment. Nail clippings and scrapings are the most common methods of sampling for suspected onychomycosis. The simplest method for detecting fungi is by way of 20% potassium hydroxide (KOH) preparations, but lately show insufficient sensitivity in onychomycosis – as much as 40–68%. Fungi can also be grown in culture form; however a 70% sensitivity detection failure rate is seen. Recently, histological fungal detection – in the form of Periodic Acid-Schiff (PAS) stain – has shown high sensitivity at 92% in the detection of fungal elements. The exact mechanism of action of laser is unknown but it is believed that heat disintegrates fungal structures. One of the most appealing characteristics of laser therapy is its ability to deliver energy to the target tissue and avoid systemic side effects at the same time. In 2009 the United Kingdom (UK) Podiatry magazine Podiatry Now published a letter suggesting laser treatment was “possibly the most radical development in the treatment of onychomycosis our profession has ever seen”, although concerns were raised over the unproven efficacy and investment costs involved. Papers have been published investigating the efficacy of lasers for the treatment of onychomycosis. Even though laser therapy provides an alternative option with rapid procedure duration, conflicting evidence is shown in a variety of papers and studies with longer follow-up periods suggest onychomycosis relapse in those treated with laser, which warrants further investigation.
关键词： Heat,Laser,Effectiveness,Review,1064 nm wavelength,Onychomycosis,Resistance,New treatment
更新于2025-09-12 10:27:22
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Onychoplasty with 1064-nm Laser: Matrixectomy for Treatment of Ingrown Toenails
摘要： Onychocryptosis is a common pathology treated by podiatry medical services, and in a considerable percentage, surgical procedures are required to achieve a solution. There are multiple surgical approaches for ingrown toenails, both incisional procedures and nonincisional procedures, such as chemical matrixectomies and physical matrixectomies using carbon dioxide laser. This study presents a surgical procedure for onychocryptosis using a physical matrixectomy with a 1064-nm laser applied by means of a 400-lm optical fiber and surgical removal of the posterior cauterized tissue to achieve healing by primary intention. This technique was performed on 30 patients with onychocryptosis affecting the great toe (Mozena stages I and IIa), and all of the patients were followed up postoperatively for 12 months. The patients reported minimal postoperative pain, quicker surgical postoperative healing, rapid return to activities of daily living, and minor postoperative recurrence compared with previous studies using incisional procedures and chemical matrixectomies.
关键词： Onychocryptosis,surgical procedure,1064-nm laser,matrixectomy,ingrown toenails
更新于2025-09-11 14:15:04
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Q-PTP is an optimized technology of 1064-nm Q-switched neodymium-doped yttrium aluminum garnet laser in the laser therapy of melasma: A prospective split-face study
摘要： Quickly-pulse-to-pulse (Q-PTP) is the latest dual pulse mode Q-switched neodymium-doped yttrium aluminum garnet [QS Nd:YAG (QSNY)] laser technology that improves efficacy and minimizes side effects. In this study, the safety, efficacy, and advantages of Q-PTP and single-pulse laser mode of 1064-nm QSNY in the treatment of melasma were compared. Twelve healthy women were enrolled in this split-face study. Q-PTP and single-pulse laser mode of 1064-nm QSNY were applied to the treatment side and the control side, respectively. Physician's global assessment, patients' self-assessment and the modified melasma area and severity index (mMASI) scores were used to quantify pigmentation changes. Side effects were recorded. Mean mMASI scores were decreased significantly at the 4th and 12th-week follow-up visit compared to the baseline. Melasma lesion clearance was more than 50% in 58% of patients compared with the baseline. However, both sides of the same patient showed similar therapeutic effect. Minor pain experience and slighter skin erythema reaction were reported in Q-PTP laser mode treatment side compared with the control. No serious complications were found in any of the patients. Q-PTP laser mode of 1064-nm QSNY is an optimal laser therapy in the treatment of melasma with greater safety and superiority.
关键词： laser toning,Q-PTP,1064-nm QS-Nd: YAG laser,melasma
更新于2025-09-11 14:15:04