Characterization of laser-induced breakdown spectroscopy on tungsten at variable ablation angles using coaxial system in vacuum

As an in situ and remote diagnostic technique, laser-induced breakdown spectroscopy (LIBS) has been well proven to detect the elemental distribution on the plasma-facing materials (PFMs) in magnetic confinement nuclear...

Design of a High-Performance Digital Slit-Lamp Microscope with Five-Switched Zoom

In this study, we design and present a five-fold digital slit-lamp microscope (DSLM) with built-in photographic lens and CCD. The initial structures of the front objective, Galilean telescope system, and photographic lens are systematically investigated and discussed in the design. A progressive optimization process is employed in the non-coaxial system design after the coaxial system achieves high performance. The analysis of spot diagrams and the modulation transfer function (MTF) show that this DSLM optical system achieves quasi-diffraction-limited performance and enables high-quality imaging for ophthalmic examination. Furthermore, tolerance analysis of this optical system is also performed, which provides a theoretical basis for machining and assembly. This design provides an idea for the design of a digital-zoom microscope in biomedical imaging instruments.

Design and Research of a Color Discrimination Method for Polycrystalline Silicon Cells Based on Laser Detection System

In this paper, a method of color discrimination based on sample sensitivity to light wavelength is proposed based on the reflection spectra of a large number of samples and the statistical calculation of the measurement data. A laser detection system is designed to realize the color discrimination. For the color discrimination of polycrystalline silicon cells, the most sensitive wavelength, 434 nm, and the least sensitive wavelength, 645 nm, of polycrystalline silicon cells is obtained according to this method. A laser detection system was built to measure the polycrystalline silicon cells. This system consists of two lasers, optical shutters, collimating beam expanding systems, an optical coaxial system, sample platform, collecting lens, and optical power meter or optical sensor. Two laser beams of different wavelengths are beamed coaxially through the optical coaxial system onto a polycrystalline silicon cell and are reflected or scattered. The reflected or scattered lights are collected through a lens with a high number aperture and received separately by the optical power meter. Then the color value of the polycrystalline silicon cell in this system is characterized by the ratio of light intensity data received. The system measured a large number of previous polycrystalline silicon cells to form the different color categories of polycrystalline silicon cells of this system in the computer database. When a new polycrystalline silicon cell is measured, the color discrimination system can automatically classify the new polycrystalline silicon cell to a certain color category in order to achieve color discrimination.

Efficacy of a coaxial system with a compliant balloon catheter for navigation of the Penumbra reperfusion catheter in tortuous arteries: technique and case experience

OBJECTIVE The authors describe a method by which they easily and atraumatically navigate a large-bore reperfusion catheter of the Penumbra system to an embolus by using a coaxial system with a compliant balloon catheter in patients with tortuous arteries. METHODS A retrospective review of the prospective endovascular database was performed to identify cases in which a coaxial system with a compliant balloon catheter (Scepter C, MicroVention/Terumo; or TransForm C, Stryker Neurovascular) and a large-bore reperfusion catheter of the Penumbra system (Penumbra, Inc.) was used. The authors achieved a stable guiding sheath position and delivered the coaxial system with a compliant balloon catheter and a large-bore reperfusion catheter. Then, the balloon was inflated somewhat when the distal tip of the balloon was slightly advanced from the tip of the reperfusion catheter, and together the coaxial system was advanced to an embolus over a 0.014-in guidewire, even around the corner. When the distal tip of the balloon catheter reached the embolus, the authors deflated the balloon and navigated the large-bore reperfusion catheter to the embolus. Finally, the aspiration of the embolus with the Penumbra MAX pump was begun. RESULTS Between May 2014 and September 2015, the authors used this technique in 17 cases: 16 cases of middle cerebral artery occlusion (including 5 cases of internal carotid artery occlusion) and 1 case of basilar artery occlusion (age range 36–88 years, mean age 74.7 years, 13 men). For the reperfusion catheter of the Penumbra system, the 5MAX ACE was used in 15 cases, and the 5MAX was used in 2 cases. As a compliant balloon catheter, the Scepter C was used in 16 cases, and the TransForm C was used in 1 case. The technique was successful in 16 cases (94.1%). No parent artery dissections were noted in any cases. Catheter-induced vasospasm was noted in 1 case, but the vasospasm was transient. CONCLUSIONS A coaxial system with a compliant balloon catheter can help safely and easily to navigate the large-bore reperfusion catheter of the Penumbra system to an embolus in patients with tortuous arteries.