460 research outputs found
Laser-to-droplet alignment sensitivity relevant for laser-produced plasma sources of extreme ultraviolet light
We present and experimentally validate a model describing the sensitivity of
the tilt angle, expansion and propulsion velocity of a tin micro-droplet
irradiated by a 1 {\mu}m Nd:YAG laser pulse to its relative alignment. This
sensitivity is particularly relevant in industrial plasma sources of extreme
ultraviolet light for nanolithographic applications. Our model has but a single
parameter: the dimensionless ratio of the laser spot size to the effective size
of the droplet, which is related to the position of the plasma critical density
surface. Our model enables the development of straightforward scaling arguments
in turn enabling precise control the alignment sensitivity.Comment: 7 pages, 5 figure
The Formative Years of the Modern Corporation: The Dutch East India Company VOC, 1602-1623
With their legal personhood, permanent capital with transferable shares, separation of ownership and management, and limited liability for both shareholders and managers, the Dutch East India Company (VOC) and subsequently the English East India Company (EIC) are generally considered a major institutional breakthrough. Our analysis of the business operations and notably the financial policy of the VOC during the company’s first two decades in existence shows that its c
An Admiralty for Asia: Isaac le Maire and conflicting conceptions about the corporate governance of the VOC
The Dutch East India Company or VOC in 1602 showed many characteristics of modern corporations, including limited liability, freely transferable shares, and well-defined managerial functions. However, we challenge the notion of the VOC as the precursor of modern corporations to argue that the company was a hybrid, combining elements from traditional partnerships with a governance structure modeled on existing public-private partnerships. The company’s charter r
Mass Partitioning in Fragmenting Tin Sheets
We experimentally study the mass partitioning of a fragmenting liquid sheet formed after the impact of a ns-laser pulse on a tin microdroplet, and its dependence on laser pulse energy and droplet size. We present the temporal evolution of individual liquid fractions: the sheet and its bounding rim, ligaments protruding from the rim, and droplets shed by the ligaments, applying machine learning to analyze subresolution fragments. Our results show that the temporal evolution of the mass partitioning between the sheet, rim, ligaments, and fragments is independent of the deformation Weber number - following Wang and Bourouiba [J. Fluid Mech. 935, A29 (2022)] for the analogous droplet-pillar impact case, extending the work to larger Weber numbers and to a system where the timescale of deformation is fully decoupled from impact. The full mass partitioning is accounted for by quantifying the further contributions unique to the laser-droplet impact case: that of a centrally located mass remnant, and the mass ablated by the laser pulse. These findings can be employed to optimize the mass utilization of the liquid tin that is used as target material in the production of extreme ultraviolet light for nanolithography.</p
Drop fragmentation by laser-pulse impact
We study the fragmentation of a liquid drop that is hit by a laser pulse. The drop expands into a thin sheet that breaks by the radial expulsion of ligaments from its rim and the nucleation and growth of holes on the sheet. By combining experimental data from two liquid systems with vastly different time and length scales, we show how the early-time laser-matter interaction affects the late-time fragmentation. We identify two Rayleigh-Taylor instabilities of different origins as the prime cause of the fragmentation and derive scaling laws for the characteristic breakup time and wavenumber. The final web of ligaments results from a subtle interplay between these instabilities and deterministic modulations of the local sheet thickness, which originate from the drop deformation dynamics and spatial variations in the laser-beam profile.</p
Speed of fragments ejected by an expanding liquid tin sheet
We experimentally investigate the speed of fragments produced by ligament breakup in the laser-induced deformation of tin microdroplets into axisymmetric sheets. The experiments were carried out covering a wide range of droplet diameters and laser-pulse energies. In addition to fragments produced by end-pinching, we also observe fragments shed via Rayleigh-Plateau breakup of long ligaments at late times. A double-frame backlit camera was used to obtain the speeds of the fragments u(f) and the time of their detachment t(d). We show that by normalizing u(f) to the initial expansion speed of the sheet R-0, all data collapse onto a single, universal curve that is a function of the dimensionless time t(d)/tau(c) only, where tau(c) is the capillary time. This universal curve is explicitly independent of the droplet's Weber number. The collapse of u(f) is supported by energy conservation arguments. Our findings enable the prediction of the instantaneous speed and position of the fragments shed from liquid tin targets used in state-of-the-art extreme ultraviolet nanolithography, facilitating the design of effective mitigation strategies against microparticulate debris
Expansion Dynamics After Laser-Induced Cavitation in Liquid Tin Microdroplets
The cavitation-driven expansion dynamics of liquid tin microdroplets is
investigated, set in motion by the ablative impact of a 15-ps laser pulse. We
combine high-resolution stroboscopic shadowgraphy with an intuitive fluid
dynamic model that includes the onset of fragmentation, and find good agreement
between model and experimental data for two different droplet sizes over a wide
range of laser pulse energies. The dependence of the initial expansion velocity
on these experimental parameters is heuristically captured in a single power
law. Further, the obtained late-time mass distributions are shown to be
governed by a single parameter. These studies are performed under conditions
relevant for plasma light sources for extreme-ultraviolet nanolithography.Comment: 7 pages, 6 figure
Drop fragmentation by laser-pulse impact
We study the fragmentation of a liquid drop that is hit by a laser pulse. The
drop expands into a thin sheet that breaks by the radial expulsion of ligaments
from its rim and the nucleation and growth of holes on the sheet. By combining
experimental data from two liquid systems with vastly different time- and
length scales we show how the early-time laser-matter interaction affects the
late-time fragmentation. We identify two Rayleigh--Taylor instabilities of
different origins as the prime cause of the fragmentation and derive scaling
laws for the characteristic breakup time and wavenumber. The final web of
ligaments results from a subtle interplay between these instabilities and
deterministic modulations of the local sheet thickness, which originate from
the drop deformation dynamics and spatial variations in the laser-beam profile.Comment: about to be submitted to JF
Impact of concomitant administration of gastric acid-suppressive agents and pazopanib on outcomes in soft-tissue sarcoma patients treated within the EORTC 62043/62072 trials
Purpose: Pazopanib is active in soft-tissue sarcoma (STS). Because pazopanib absorption is pH-dependent, coadministration with gastric acid-suppressive (GAS) agents such as proton pump inhibitors could affect exposure of pazopanib, and thereby its therapeutic effects.Experimental Design: The EORTC 62043 and 62072 were single-arm phase II and placebo-controlled phase III studies, respectively, of pazopanib in advanced STS. We first compared the outcome of patients treated with pazopanib with or without GAS agents for ≥80% of treatment duration, and subsequently using various thresholds. The impact of concomitant GAS therapy was assessed on progression-free survival (PFS) and overall survival (OS) using multivariate Cox models, exploring and comparing also the potential effect on placebo-treated patients.Results: Of 333 eligible patients, 59 (17.7%) received concomitant GAS therapy for >80% of pazopanib treatment duration. Median PFS was shorter in GAS therapy users versus nonusers: 2.8 vs. 4.6 months, respectively [HR, 1.49; 95% confidence interval (CI), 1.11-1.99; P = 0.01]. Concomitant administration of GAS therapy was also associated with a shorter median OS: 8.0 vs. 12.6 months (HR, 1.81; 95% CI, 1.31-2.49; P < 0.01). The longer the overlapping use of GAS agents and pazopanib, the worse the outcome with pazopanib. These effects were not observed in placebo-treated patients (HR, 0.82; 95% CI, 0.51-1.34; P = 0.43 for PFS and HR, 0.84; 95% CI, 0.48-1.48; P = 0.54 for OS).Conclusions: Coadministration of long-term GAS therapy with pazopanib was associated with significantly shortened PFS and OS. Withdrawal of GAS agents must be considered whenever possible. Therapeutic drug monitoring of pazopanib plasma concentrations may be helpful for patients on pazopanib and GAS therapy
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