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An apparatus for measuring a material's photomechanical response
摘要： This paper describes a simple and inexpensive apparatus for measuring the light-induced shape change of a material, which can be implemented in a high school or undergraduate laboratory. The key components of the apparatus are a laser pointer to actuate the material, a force sensor from an inexpensive jeweler’s balance to measure the response, an Arduino for data acquisition, and a means for mechanically mounting the setup. The apparatus described here was used by high school students and teachers in a summer program to characterize liquid crystal elastomer samples. The theory of photomechanical response is used to interpret the gathered data, from which material parameters related to this theory are determined.
关键词： photomechanical effect,liquid crystal elastomers,Arduino,laser pointer,force sensor
更新于2025-09-23 15:21:01
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A Simple Method to Test Microscope Objectives Using a Laser Pointer
摘要： The objective lens is regarded as the critical component for an optimal image in light microscopy. Not every damage to the lens surface may be easily visible during maintenance when the objective is removed and observed. The internal lens organization produces a magnified image of the outer lens surface. Shining the light of a laser pointer into the lens, and reproducing the image of the light exiting onto a flat surface, produces different images for intact and damaged objective lenses.
关键词： damaged lens,laser pointer,light microscope,maintenance,objective lens
更新于2025-09-19 17:13:59
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LONG-TERM VISUAL RECOVERY IN BILATERAL HANDHELD LASER POINTER–INDUCED MACULOPATHY
摘要： To describe the long-term visual, clinical, and optical coherence tomography (OCT) recovery after 4 years in a patient who incurred severe bilateral handheld laser pointer damage. The findings on clinical examination, color fundus photography, and spectral domain OCT at presentation followed by sequential time points over 4 years are presented. A 9-year-old healthy boy presented with bilateral reduced vision to count fingers in each eye with yellow irregular lesions. After extensive evaluation, he admitted to multiple, prolonged episodes of staring at a handheld red laser pointer reflected in a mirror. Initial visual acuity was count fingers bilaterally. Clinical examination revealed bilateral yellow streaks radiating from the fovea without hemorrhages or fluid and retinal pigment epithelium pigmentary mottling. Spectral domain OCT showed disruption of the foveal outer retina extending from the outer plexiform layer to the retinal pigment epithelium spanning 896 mm in the right eye and 564 mm in the left eye. Six months after injury, vision had only minimally improved to 20/200 with resolution of outer plexiform layer and outer nuclear layer opacification on OCT. Over the ensuing 4 years, visual acuity slowly recovered to 20/30 in each eye and the regions of outer retinal disruption progressively reduced in size to 295 mm in the right eye and 115 mm in the left eye. This case illustrates gradual vision and anatomical improvement over 4 years despite initial poor vision after severe laser pointer macular damage. Visual recovery may be related to patient and exposure factors as well as initial OCT features where an intact Bruch membrane can provide a scaffold for photoreceptors to recover, thereby reducing the outer retinal defect.
关键词： handheld laser,Henle’s fiber layer,OCT,laser pointer,retina,photic maculopathy
更新于2025-09-16 10:30:52
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[Laser Institute of America ILSC? 2019: Proceedings of the International Laser Safety Conference - South Kissimmee, Florida, USA (March 18–21, 2019)] International Laser Safety Conference - Reducing hazards of consumer laser pointer misuse
摘要： This paper begins with a review of significant laser pointer news since ILSC 2017. These include new laws in the U.K., Canada and Switzerland; an MIT-developed laser pointer detection system, the SAE-published ARP6378 with pilot mitigation recommendations, a review of 111 laser pointer eye injuries worldwide, the status of FDA’s 2016 proposal to allow only red laser pointers, and the new LaserIncidents.com website that lists known databases that compile laser incidents and accidents. The paper then looks at methods for reducing the number and severity of laser pointer incidents. For example, Australia and New Zealand have laws severely restricting ownership of laser pointers over 1 mW. In Australia, aircraft incidents increased significantly after the 2008 ban and currently are roughly equal to U.S. incidents on a per capita basis. In New Zealand, aircraft incidents increased after a ban went into effect in 2014. The ARP6378 document cites pilots as the last line of defense. Pilot education, training and protective eyewear/windscreens are discussed in the document. Changes in labeling are suggested. The usefulness of prosecuting laser offenders is discussed. A summary is given of a Jan. 2019 symposium in Tokyo, seeking new laws and ideas for reducing aircraft incidents, consumer eye injuries, and injuries from laser cosmetic devices. Finally, suggested directions for future research are given.
关键词： misuse,aircraft,pilot training,regulations,hazards,eye injuries,laser pointer,labeling
更新于2025-09-12 10:27:22
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Response to Underwater Laser Pointer in the Orange‐Finned Anemonefish <i>Amphiprion chrysopterus</i> and three‐spot damselfish <i>Dascyllus trimaculatus</i>
摘要： Response of orange-finned anemonefish Amphiprion chrysopterus and three-spot damselfish Dascyllus trimaculatus to red laser-pointer light was studied in Mo’orea, French Polynesia. Four magnificent anemones Heteractis magnifica and their resident fish were observed for typical behaviours (biting, chasing, hiding, posing, lunging and retreating) with and without exposure to laser-pointer light. Lunging behaviour increased significantly for both fish species upon exposure to laser-pointer light; none of the other behaviours changed significantly. We advance the hypothesis that orange-finned anemonefish and three-spot damselfish interpret laser pointer stimulation as a territorial threat.
关键词： boldness,laser pointer,French Polynesia,Moorea,anemonefish
更新于2025-09-12 10:27:22