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Partial Scleral Rupture Presenting 4 Years After Laser in Situ Keratomileusis
摘要： To report a case of partial scleral rupture after laser in situ keratomileusis (LASIK) surgery. This is a retrospective case report describing a late complication of LASIK surgery. A 32-year-old white woman with a history of LASIK surgery performed with a mechanical microkeratome 4 years previously presented for evaluation of partial bilateral scleral ruptures. An arcuate ?ltering bleb along the contour of the cornea was found on the right eye with associated hypotony and corneal astigmatism. There were no signs or symptoms of prior in?ammation, and rheumatologic workup was negative. Imaging revealed scleral microbreaks in the absence of adjacent thinning. The pattern and location of thinning without ?ndings consistent with in?ammatory disease suggest that the partial bilateral scleral rupture was because of mechanical damage at the time of LASIK, possibly compounded by the hormonal changes of pregnancy.
关键词： scleral rupture,complications,complication,hypotony,scleral microbreaks,laser in situ keratomileusis (LASIK)
更新于2025-09-12 10:27:22
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In-situ characterization of tungsten microcracking in Selective Laser Melting
摘要： Additive Manufacturing is a promising way of processing tungsten, with opportunities to create more complex parts than are possible using other powder metallurgical routes. This may lead to extended applications such as collimators, in fusion reactors, or in other structurally loaded, high temperature environments. The poor thermal shock resistance and ductile-to-brittle transition that occurs in tungsten above room temperature are challenges that hinder production of fully dense and crack free parts. This research employs high speed in-situ monitoring of Selective Laser Melting of single tracks to visualize crack initiation and propagation. The circumstances that lead to cracking are correlated with microstructural morphology and processing conditions.
关键词： In-situ monitoring,Additive Manufacturing,Microcracking,Laser powder bed fusion,Tungsten,Selective Laser Melting
更新于2025-09-12 10:27:22
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Laser processing quality monitoring by combining acoustic emission and machine learning: a high-speed X-ray imaging approach
摘要： In situ and real-time monitoring of laser processes are very challenging due to complex dynamics of the laser-matter interactions. Acoustic emission (AE) technique is often used as non-destructive monitoring of many kinds of processes. However, acoustic emission is not industrialized for laser processing for two reasons. First, the signals are too sensitive to the environmental noises. Second, a correlation of the acoustic emission signal with the real events is very difficult to realize despite being of utmost importance. To overcome these difficulties, we combined fast hard X-ray imaging with acoustic sensors and state-of-the-art machine learning.
关键词： monitoring,machine learning,High speed X-ray,acoustic,in situ and real-time,Laser welding
更新于2025-09-12 10:27:22
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Why is in situ quality control of laser keyhole welding a real challenge?
摘要： In this work, we investigated keyhole welding including the pore dynamics (creation and collapse) of aluminium at the European Synchrotron Radiation Facility (ESRF, Grenoble, France). Optical back reflection and acoustic signals were simultaneously recorded during the welding process which was also visualized by high-speed X-ray imaging. This allows correlating the different momentary events with the signals recorded by the sensors. We demonstrate that keyhole welding is a highly dynamical and unstable process. In addition, to use either acoustic or optical sensors for pore detection, highly advance statistical methods such as machine learning are a requisite for signal processing.
关键词： in-situ monitoring,acoustic emission,X-ray imaging,Laser welding
更新于2025-09-12 10:27:22
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Spatial modulation of laser sources for microstructural control of additively manufactured metals
摘要： Metal powder-bed fusion additive manufacturing (AM), while demonstrating great potential across a diverse application space, still lacks the necessary control to obtain parts that meet strict performance-driven criteria. In this work, we explore spatial laser modulation to enhance the properties and processability of AM metals. Experiments are carried out with the goals of demonstrating control of the columnar-to-equiaxed transition, identify methods to reduce surface roughness, and extend processing windows for AM alloys. Results show that beam modulation provides site-specific microstructural control, and these results are interpreted using finite element modeling of the melt pool dynamics and thermal profiles.
关键词： In situ monitoring,Microstructure,Additive Manufacturing,Beam shaping,Selective Laser Melting
更新于2025-09-12 10:27:22
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In-Situ process monitoring during laser transmission welding of PA6-GF30
摘要： Quasi-simultaneous laser transmission welding is preferably used for packaging sensors and electronics. In order to protect the components from moisture, a hermetic encapsulation is needed. However, local weld seam interruptions cannot be identified with the commonly used set-path monitoring. By using a pyrometer, coaxially integrated into a 3D-scanner, gaps between the joining partners can be allocated on basis of the measured temperature. However, the scattering of the heat radiation, especially caused by the fiber reinforcement of the plastics, leads to a reduction of the accessible heat radiation, which makes the identification of gaps considerably more difficult. The herein used experimental setup is characterized by a small detection spot and only by a slight weakening of the heat radiation inside the scanner. Hence, for welding PA6-GF30, the detection of small sized gaps is possible, even if a glass fiber content of 30 percent (wt.) and a weld seam width with approximately 1 mm are given.
关键词： in-situ monitoring,plastics welding,pyrometer,temperature measurement,fiber reinforced plastics
更新于2025-09-12 10:27:22
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Outcomes of emergency in situ laser fenestration-assisted thoracic endovascular aortic repair in patients with acute Stanford type A aortic dissection unfit for open surgery
摘要： Objective: This study investigated the outcomes of emergency in situ laser fenestration (ISLF)-assisted thoracic endovascular aortic repair (TEVAR) for patients with acute Stanford type A aortic dissection unfit for open surgery. Methods: Twenty patients with acute Stanford type A aortic dissection who were found to be unfit for open surgery, underwent emergency ISLF-assisted TEVAR in our center between March 2016 and December 2018. Anatomic criteria for endovascular repair: coronary artery and aortic valve was not involved, proximal landing zone diameter of 45 mm or less, and proximal landing zone length of 20 mm or greater. Their clinical outcomes were reviewed retrospectively. Results: Twenty patients achieved a procedural success of 100.0%. The 30-day mortality was 10%; two patients died, one of severe pneumonia and the other from cerebral hemorrhage after the operation. Rate of stroke at 30 days was 5%. The average follow-up time was 16 months (range, 3-26 months). One death owing to heart failure occurred at 23 months postoperatively. Kaplan-Meier curve analysis revealed that the 24-month survival rate was 77.1%. Two patients had type Ia endoleaks and one had a type II endoleak. There was no stent graft migration or fenestration-related endoleak and all patients had a thrombosed false lumen in the covered section of the stent grafts. No reintervention, myocardial infarction, transient ischemic attacks, cerebral infarction, or other complications occurred during the follow-up period. Conclusions: Emergency ISLF-assisted TEVAR is a safe and effective alternative method for treating acute Stanford type A aortic dissection unfit for open surgery.
关键词： Laser,TEVAR,In situ fenestration,Aortic dissection
更新于2025-09-12 10:27:22
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In-situ measurement of near-tip fatigue crack displacement variation in laser melting deposited Ti-6.5Al-3.5Mo-1.5Zr-0.3Si titanium alloy
摘要： Laser melting deposition (LMD) is an attractive additive manufacturing technique for fabricating titanium alloy components. A variety of distinct layer bands, heat affected bands (HABs), were found in the LMDed sample, which lead to a periodic fluctuation in the fatigue crack growth rate. In this paper, an in-situ fatigue testing was performed to investigate the crack tip opening displacement (CTOD) variation within a full loading cycle. Digital image correlation (DIC) technique was implemented for obtaining the displacement fields at the vicinity of the crack tip. The crack closure phenomenon is observed from the CTOD variation and the crack opening stress level is different between HAB and non-HAB zone. Another key difference between HAB and non-HAB zone is the value of CTOD when the crack is opening. Besides, the variation of the CTOD loop and its influence on fatigue crack growth rate were also discussed in detail.
关键词： Digital image correlation,In-situ,Crack tip opening displacement,Laser melting deposition
更新于2025-09-12 10:27:22
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Fibrin glue to manage flap necrosis secondary to late-onset infectious keratitis after laser in?situ karatomileusis
摘要： A 52-year-old man developed flap necrosis secondary to late-onset infectious keratitis after laser in situ keratomileusis. Management involved a flap lift and irrigation of the interface with fortified antibiotics. The flap was then replaced, and fibrin glue was placed at the flap edges and over the necrotic area to seal it completely. Two months after surgery, the corrected distance visual acuity was 20/20 and a slitlamp examination showed no signs of infection. Localized flap necrosis can be adequately managed with fibrin glue, including in cases of herpes simplex virus keratitis.
关键词： fibrin glue,infectious keratitis,flap necrosis,herpes simplex virus,laser in situ keratomileusis
更新于2025-09-12 10:27:22
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Real-Time Electron Nanoscopy of Photovoltaic Absorber Formation from Kesterite Nanoparticles
摘要： Cu2ZnSnS4 nanocrystals are annealed in a Se-rich atmosphere inside a transmission electron microscope. During the heating phase, a complete S-Se exchange reaction occurs while the cation sublattice and morphology of the nanocrystals are preserved. At the annealing temperature, growth of large Cu2ZnSnSe4 grains with increased cation ordering is observed in real-time. This yields an annealing protocol which is transferred to an industrially-similar solar cell fabrication process resulting in a 33% increase in the device open circuit voltage. The approach can be applied to improve the performance of any photovoltaic technology that requires annealing because of the criticality of the process step.
关键词： cation ordering,Kesterite,photovoltaics,in situ transmission electron microscopy (TEM),annealing
更新于2025-09-12 10:27:22