Refractive error correction for in situ curvature measurement using laser beam deflection method

2010 ◽  
Vol 107 (1) ◽  
pp. 013508 ◽  
Author(s):  
Xinran Xiao ◽  
Daniel Schleh
Keyword(s):  
Laser Beam ◽  
Error Correction ◽  
Refractive Error ◽  
Beam Deflection ◽  
Curvature Measurement

scholarly journals Carbon Particle In-Situ Alloying of the Case-Hardening Steel 16MnCr5 in Laser Powder Bed Fusion

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 896
Author(s):  
Matthias Schmitt ◽  
Albin Gottwalt ◽  
Jakob Winkler ◽  
Thomas Tobie ◽  
Georg Schlick ◽  
...  
Keyword(s):  
Laser Beam ◽  
Mechanical Strength ◽  
Carbon Content ◽  
Metal Powder ◽  
Case Hardening ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Carbon Particles ◽  
Case Hardening Steel

The carbon content of steel affects many of its essential properties, e.g., hardness and mechanical strength. In the powder bed fusion process of metals using a laser beam (PBF-LB/M), usually, pre-alloyed metal powder is solidified layer-by-layer using a laser beam to create parts. A reduction of the carbon content in steels is observed during this process. This study examines adding carbon particles to the metal powder and in situ alloying in the PBF-LB/M process as a countermeasure. Suitable carbon particles are selected and their effect on the particle size distribution and homogeneity of the mixtures is analysed. The workability in PBF-LB is then shown. This is followed by an evaluation of the resulting mechanical properties (hardness and mechanical strength) and microstructure in the as-built state and the state after heat treatment. Furthermore, potential use cases like multi-material or functionally graded parts are discussed.

A quality of life assessment of military recruits after refractive surgery

2020 ◽  
Vol 1 (1) ◽  
pp. 42-46
Author(s):  
Jian-He Xiao ◽  
◽  
Shi-Yang Li ◽  
Xing Xing ◽  
Ai-Hong Zhao ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Refractive Error ◽  
High Myopia ◽  
Refractive Surgery ◽  
Laser In Situ Keratomileusis ◽  
Significant Difference ◽  
Lenticule Extraction ◽  
Postoperative Interval

AIM: To evaluate the quality of life of recruits after refractive surgery. METHODS: Population-based, cross-sectional study. Using the Quality of Life Impact of Refractive Correction (QIRC) questionnaire, the quality of life in 615 recruits underwent refractive surgery was evaluated. The overall score and each question score of QIRC were compared between subgroups of different strength of preoperative refractive error, postoperative interval, type of surgical procedure and postoperative recovery. RESULTS: The mean overall QIRC score of recruits underwent refractive surgery was 49.15±7.89. Significant difference was found for strength of preoperative refractive error (F=4.16, P<0.05), with the low myopia group (50.67±7.59) had significantly better scores than those with high myopia (47.57±7.52, F=4.16, P<0.05). Recruits after a postoperative interval no more than 6mo (49.18±7.86) scored equally to those of more than 6mo (49.18±8.03). Recruits underwent surface ablation surgery scored lowest (46.68±6.09), but showed no significant difference when compared with all underwent refractive surgery (t=1.99, P>0.05). Scores of recruits underwent mechanical microkeratome laser in situ keratomileusis (MK-LASIK), Sub-Bowman’s keratomileusis (SBK), femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK), femtosecond lenticule extraction (ReLEx flex) or small-incision lenticule extraction (ReLEx SMILE) procedure showed no significant difference too. Recruits had adverse complaints postoperatively (45.85±6.66) scored lower when compared with all underwent refractive surgery (t=5.28, P<0.01). CONCLUSION: The quality of life of recruits after refractive surgery was good except those with postoperative complications. Preoperative low myopia recruits had better quality of life than medium and high myopia ones.

Laboratory Experience with In Situ Detection of Beryllium in Biological Specimens

1968 ◽  
Vol 22 (6) ◽  
pp. 758-760 ◽  
Author(s):  
Solomon F. Brokeshoulder ◽  
Farrel R. Robinson
Keyword(s):  
Chemical Analysis ◽  
Laser Beam ◽  
Tissue Thickness ◽  
Laboratory Experience ◽  
Laser Microprobe ◽  
Medium Concentration ◽  
Embedding Medium ◽  
In Situ Detection

Suitable microspectrochemical techniques have been devised for the laser microprobe made by the Jarrell—Ash Co. to detect beryllium in histologic structures. Density and type of tissue, thickness of the specimen, character of the embedding medium, concentration and localization of the element, and the penetrability of the laser beam must be considered in preparing biological specimens for chemical analysis by the microspectrochemical technique. Advantages of this technique are the identification of specific elements in situ and the correlation of the presence of the element with a specific histologic structure.

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