Pulse Delay Effects in the He–Ne Laser Mode‐Locked by a Ne Absorption Cell

1969 ◽  
Vol 40 (10) ◽  
pp. 3969-3972 ◽  
Author(s):  
A. Frova ◽  
M. A. Duguay ◽  
C. G. B. Garrett ◽  
S. L. McCall
Keyword(s):  
Absorption Cell ◽  
Laser Mode ◽  
Pulse Delay ◽  
Delay Effects

Pulse-delay effects in the angular distribution of near-threshold EUV + IR two-photon ionization of Ne

2014 ◽  
Vol 89 (1) ◽  
Author(s):  
S. Mondal ◽  
H. Fukuzawa ◽  
K. Motomura ◽  
T. Tachibana ◽  
K. Nagaya ◽  
...  
Keyword(s):  
Angular Distribution ◽  
Pulse Delay ◽  
Two Photon ◽  
Delay Effects ◽  
Photon Ionization ◽  
Near Threshold

Time Delay Effects on Compactability of Soil-Cement Materials during Proctor Testing

2021 ◽  
pp. 036119812199870
Author(s):  
W. Griffin Sullivan ◽  
Isaac L. Howard
Keyword(s):  
Time Delay ◽  
Vital Role ◽  
Test Method ◽  
Dry Density ◽  
Soil Cement ◽  
Delay Effects ◽  
Proctor Test ◽  
Negative Effect ◽  
Departments Of Transportation ◽  
Cement Mixtures

The Proctor test method, as specified in AASHTO T134 and ASTM D558, continues to play a vital role in design and construction quality control for soil-cement materials. However, neither test method establishes a methodology or standardized protocols to characterize the effects of time delay between cement addition and compaction, also known as compaction delay. Compaction delay has been well documented to have a notably negative effect on compactability, compressive strength, and overall performance of soil-cement materials, but specification tools to address this behavior are not prevalent. This paper aims to demonstrate the extent of compaction delay effects on several soil-cement mixtures used in Mississippi and to present recommended new test method protocols for AASHTO T134 to characterize compaction delay effects. Data presented showed that not all soil-cement mixtures are sensitive to compaction delay, but some mixtures can be very sensitive and lead to a meaningful decrease in specimen dry density. Recommended test method protocols were presented for AASHTO T134 and commentary was presented to provide state Departments of Transportation and other specifying agencies a few examples of how the new compaction delay protocols could be implemented.

scholarly journals Electric Field Assisted Femtosecond Laser Preparation of Au@TiO2 Composites with Controlled Morphology and Crystallinity for Photocatalytic Degradation

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3816
Author(s):  
Xiaojie Li ◽  
Xin Li ◽  
Pei Zuo ◽  
Xiaozhe Chen ◽  
Misheng Liang ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Electric Field ◽  
Photocatalytic Degradation ◽  
Au Nanoparticles ◽  
High Efficiency ◽  
Free Electron Density ◽  
Pulse Delay ◽  
Dye Pollutants ◽  
Amorphous Tio2 ◽  
Laser Liquid

TiO2 is popular in photocatalytic degradation dye pollutants due to its abundance and its stability under photochemical conditions. Au loaded TiO2 can achieve efficient absorption of visible light and deal with the problem of low conversion efficiency for solar energy of TiO2. This work presents a new strategy to prepare Au nanoparticles-loaded TiO2 composites through electric−field−assisted temporally−shaped femtosecond laser liquid-phase ablation of Au3+ and amorphous TiO2. By adjusting the laser pulse delay and electric field parameters, gold nanoparticles with different structures can be obtained, such as nanospheres, nanoclusters, and nanostars (AuNSs). AuNSs can promote the local crystallization of amorphous TiO2 in the preparation process and higher free electron density can also be excited to work together with the mixed crystalline phase, hindering the recombination between carriers and holes to achieve efficient photocatalytic degradation. The methylene blue can be effectively degraded by 86% within 30 min, and much higher than the 10% of Au nanoparticles loaded amorphous TiO2. Moreover, the present study reveals the crystallization process and control methods for preparing nanoparticles by laser liquid ablation, providing a green and effective new method for the preparation of high-efficiency photocatalytic materials.

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