Imprinting of laser nonuniformity is a limiting factor in direct-drive inertial confinement fusion experiments, particularly when available laser smoothing is limited. A thin (∼400 Å) high-Z metal coating is found to substantially suppress laser imprint for planar targets driven by pulse shapes and intensities relevant to implosions on the National Ignition Facility while retaining low adiabat target acceleration. A hybrid of indirect and direct drive, this configuration results in initial ablation by x rays from the heated high-Z layer, creating a large standoff for perturbation smoothing.
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http://dx.doi.org/10.1103/PhysRevLett.114.085001 | DOI Listing |
In this Letter, we show the attraction of a microbubble at a fiber end face by the solute Marangoni force. The microbubble is formed by partial filling of an ethanol-water mixture in the microcavity that is spliced to the end face of a single-mode fiber. Due to different surface tension of ethanol and water, the uneven temperature gradient induced by a laser causes the non-uniform distribution of ethanol-water molecules on the bubble surface.
View Article and Find Full Text PDFMikrochim Acta
January 2025
Centre for Micro and Nano Devices, Department of Physics, COMSATS Institute of Information Technology, Islamabad, 44500, Pakistan.
Traditional surface-enhanced Raman scattering (SERS) substrates seeking uniformity and reproducibility of the Raman signal often assume and require that hot spots remain consistently stable during Raman testing. Recently, the non-uniform accumulation in SERS sample pre-concentration strategies have inspired the direct use of self-healing noble metal aerogels (NMAs), as the sample pretreatment presented in this work, and uncovered more diverse Raman information of substances during the dynamic process of laser irradiation. Rare characteristic peaks such as 820 cm⁻ for R6G within a specific concentration range were observed, and potential processes including R6G dimerization and desorption were analyzed.
View Article and Find Full Text PDF3D Print Addit Manuf
October 2024
School of Electronics and Information Engineering, Guangdong Ocean University, Zhanjiang, China.
The large amount of unfused powder that remains on the surface of Ti6AL4V porous scaffolds prepared by selective laser melting technology is a common problem. Therefore, this article investigated the effects of three different chemical polishing processes on the surface state, pore structure, and mechanical properties of small pore size scaffold materials at different polishing times in the field of implantable medical devices. The results show that the overall treatment effect of the simple chemical polishing process is poor, the internal treatment depth of porous support is insufficient and uneven, and the overall mechanical properties of the sample with the same porosity are average.
View Article and Find Full Text PDFSensors (Basel)
November 2024
Graduate School of Applied Science and Engineering, National Defense Academy, Yokosuka 239-8686, Japan.
Various types of dielectrophoresis (DEP) cell separation devices using AC electric fields have been proposed and developed. However, its capability is still limited by a lack of quantitative characterization of the relationship between frequency and force. In the present study, this limitation was addressed by developing a method capable of fast and accurate quantification of the dielectric properties of biological cells.
View Article and Find Full Text PDFRev Sci Instrum
December 2024
Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
One regime of experimental particle-laden flow study involves ejecta microjets-often defined as a stream of micrometer-scale particles generated through shock interaction with a non-uniform surface and generally travel above 1 km/s. In order to capture the change in characteristics as a function of propagation time, we apply a multi-frame x-ray radiography platform to observe and track the jet transport dynamics. A synchrotron x-ray source allows us to perform quantitative analyses and comparisons between the eight images captured by the imaging system.
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