131 research outputs found
Q-Switched 2Â Micron Solid-State Lasers and Their Applications
In this chapter, we overview the Q-switched 2 μm solid-state laser development achieved in recent years, including flash- and diode-pumped solid-state lasers based on active and passive modulators. In summary, active Q-switching is still the first choice for obtaining large pulse energy at 2 μm currently, while passive Q-switching based on saturable absorbers (SAs), especially the newly emerging broadband low-dimension nanomaterial, is becoming promising approach in generating Q-switched 2 μm lasers specially with high repetition rate, although the output power, pulse duration, and pulse energy needs further enhancement. Besides, some important applications of 2 μm lasers, such as medicine, laser radar, and infrared directional interference, have also been introduced in brief
ODSum: New Benchmarks for Open Domain Multi-Document Summarization
Open-domain Multi-Document Summarization (ODMDS) is a critical tool for
condensing vast arrays of documents into coherent, concise summaries. With a
more inter-related document set, there does not necessarily exist a correct
answer for the retrieval, making it hard to measure the retrieving performance.
We propose a rule-based method to process query-based document summarization
datasets into ODMDS datasets. Based on this method, we introduce a novel
dataset, ODSum, a sophisticated case with its document index interdependent and
often interrelated. We tackle ODMDS with the \textit{retrieve-then-summarize}
method, and the performance of a list of retrievers and summarizers is
investigated. Through extensive experiments, we identify variances in
evaluation metrics and provide insights into their reliability. We also found
that LLMs suffer great performance loss from retrieving errors. We further
experimented methods to improve the performance as well as investigate their
robustness against imperfect retrieval. We will release our data and code at
https://github.com/yale-nlp/ODSum
Electric quadrupole second harmonic generation revealing dual magnetic orders in a magnetic Weyl semimetal
Broken symmetries and electronic topology are nicely manifested together in
the second order nonlinear optical responses from topologically nontrivial
materials. While second order nonlinear optical effects from the electric
dipole (ED) contribution have been extensively explored in polar Weyl
semimetals (WSMs) with broken spatial inversion (SI) symmetry, they are rarely
studied in centrosymmetric magnetic WSMs with broken time reversal (TR)
symmetry due to complete suppression of the ED contribution. Here, we report
experimental demonstration of optical second harmonic generation (SHG) in a
magnetic WSM CoSnS from the electric quadrupole (EQ)
contribution. By tracking the temperature dependence of the rotation anisotropy
(RA) of SHG, we capture two magnetic phase transitions, with both the SHG
intensity increasing and its RA pattern rotating at =175K and
=120K subsequently. The fitted critical exponents for the SHG
intensity and RA orientation near and suggest that the
magnetic phase at is a 3D Ising-type out-of-plane ferromagnetism
while the other at is a 3D XY-type all-in-all-out in-plane
antiferromagnetism. Our results show the success of detection and exploration
of EQ SHG in a centrosymmetric magnetic WSM, and hence open the pathway towards
the future investigation of its tie to the band topology.Comment: 19 pages, 4 figure
Disorder and diffuse scattering in single-chirality (TaSe)I crystals
The quasi-one-dimensional chiral compound (TaSe)I has been
extensively studied as a prime example of a topological Weyl semimetal. Upon
crossing its phase transition temperature 263 K,
(TaSe)I exhibits incommensurate charge density wave (CDW) modulations
described by the well-defined propagation vector (0.05, 0.05, 0.11),
oblique to the TaSe chains. Although optical and transport properties
greatly depend on chirality, there is no systematic report about chiral domain
size for (TaSe)I. In this study, our single-crystal scattering
refinements reveal a bulk iodine deficiency, and Flack parameter measurements
on multiple crystals demonstrate that separate (TaSe)I crystals have
uniform handedness, supported by direct imaging and helicity dependent THz
emission spectroscopy. Our single-crystal X-ray scattering and calculated
diffraction patterns identify multiple diffuse features and create a real-space
picture of the temperature-dependent (TaSe)I crystal structure. The
short-range diffuse features are present at room temperature and decrease in
intensity as the CDW modulation develops. These transverse displacements, along
with electron pinning from the iodine deficiency, help explain why
(TaSe)I behaves as an electronic semiconductor at temperatures above
and below , despite a metallic band structure calculated from
density functional theory of the ideal structure.Comment: 24 pages, 20 figures, 3 table
Strengthening mechanisms in thermomechanically processed NbTi-microalloyed steel
The effect of deformation temperature on microstructure and mechanical properties was investigated for thermomechanically processed NbTi-microalloyed steel with ferrite-pearlite microstructure. With a decrease in the finish deformation temperature at 1348 K to 1098 K (1075 °C to 825 °C) temperature range, the ambient temperature yield stress did not vary significantly, work hardening rate decreased, ultimate tensile strength decreased, and elongation to failure increased. These variations in mechanical properties were correlated to the variations in microstructural parameters (such as ferrite grain size, solid solution concentrations, precipitate number density and dislocation density). Calculations based on the measured microstructural parameters suggested the grain refinement, solid solution strengthening, precipitation strengthening, and work hardening contributed up to 32 pct, up to 48 pct, up to 25 pct, and less than 3 pct to the yield stress, respectively. With a decrease in the finish deformation temperature, both the grain size strengthening and solid solution strengthening increased, the precipitation strengthening decreased, and the work hardening contribution did not vary significantly
Actively implementing an evidence-based feeding guideline for critically ill patients (NEED): a multicenter, cluster-randomized, controlled trial
Background: Previous cluster-randomized controlled trials evaluating the impact of implementing evidence-based guidelines for nutrition therapy in critical illness do not consistently demonstrate patient benefits. A large-scale, sufficiently powered study is therefore warranted to ascertain the effects of guideline implementation on patient-centered outcomes.
Methods: We conducted a multicenter, cluster-randomized, parallel-controlled trial in intensive care units (ICUs) across China. We developed an evidence-based feeding guideline. ICUs randomly allocated to the guideline group formed a local "intervention team", which actively implemented the guideline using standardized educational materials, a graphical feeding protocol, and live online education outreach meetings conducted by members of the study management committee. ICUs assigned to the control group remained unaware of the guideline content. All ICUs enrolled patients who were expected to stay in the ICU longer than seven days. The primary outcome was all-cause mortality within 28 days of enrollment.
Results: Forty-eight ICUs were randomized to the guideline group and 49 to the control group. From March 2018 to July 2019, the guideline ICUs enrolled 1399 patients, and the control ICUs enrolled 1373 patients. Implementation of the guideline resulted in significantly earlier EN initiation (1.20 vs. 1.55 mean days to initiation of EN; difference − 0.40 [95% CI − 0.71 to − 0.09]; P = 0.01) and delayed PN initiation (1.29 vs. 0.80 mean days to start of PN; difference 1.06 [95% CI 0.44 to 1.67]; P = 0.001). There was no significant difference in 28-day mortality (14.2% vs. 15.2%; difference − 1.6% [95% CI − 4.3% to 1.2%]; P = 0.42) between groups.
Conclusions: In this large-scale, multicenter trial, active implementation of an evidence-based feeding guideline reduced the time to commencement of EN and overall PN use but did not translate to a reduction in mortality from critical illness. Trial registration: ISRCTN, ISRCTN12233792. Registered November 20th, 2017
Actively implementing an evidence-based feeding guideline for critically ill patients (NEED): a multicenter, cluster-randomized, controlled trial.
BackgroundPrevious cluster-randomized controlled trials evaluating the impact of implementing evidence-based guidelines for nutrition therapy in critical illness do not consistently demonstrate patient benefits. A large-scale, sufficiently powered study is therefore warranted to ascertain the effects of guideline implementation on patient-centered outcomes.MethodsWe conducted a multicenter, cluster-randomized, parallel-controlled trial in intensive care units (ICUs) across China. We developed an evidence-based feeding guideline. ICUs randomly allocated to the guideline group formed a local "intervention team", which actively implemented the guideline using standardized educational materials, a graphical feeding protocol, and live online education outreach meetings conducted by members of the study management committee. ICUs assigned to the control group remained unaware of the guideline content. All ICUs enrolled patients who were expected to stay in the ICU longer than seven days. The primary outcome was all-cause mortality within 28 days of enrollment.ResultsForty-eight ICUs were randomized to the guideline group and 49 to the control group. From March 2018 to July 2019, the guideline ICUs enrolled 1399 patients, and the control ICUs enrolled 1373 patients. Implementation of the guideline resulted in significantly earlier EN initiation (1.20 vs. 1.55 mean days to initiation of EN; difference - 0.40 [95% CI - 0.71 to - 0.09]; P = 0.01) and delayed PN initiation (1.29 vs. 0.80 mean days to start of PN; difference 1.06 [95% CI 0.44 to 1.67]; P = 0.001). There was no significant difference in 28-day mortality (14.2% vs. 15.2%; difference - 1.6% [95% CI - 4.3% to 1.2%]; P = 0.42) between groups.ConclusionsIn this large-scale, multicenter trial, active implementation of an evidence-based feeding guideline reduced the time to commencement of EN and overall PN use but did not translate to a reduction in mortality from critical illness.Trial registrationISRCTN, ISRCTN12233792 . Registered November 20th, 2017
Actively implementing an evidence-based feeding guideline for critically ill patients (NEED): a multicenter, cluster-randomized, controlled trial (vol 26, 46, 2022)
BackgroundPrevious cluster-randomized controlled trials evaluating the impact of implementing evidence-based guidelines for nutrition therapy in critical illness do not consistently demonstrate patient benefits. A large-scale, sufficiently powered study is therefore warranted to ascertain the effects of guideline implementation on patient-centered outcomes.MethodsWe conducted a multicenter, cluster-randomized, parallel-controlled trial in intensive care units (ICUs) across China. We developed an evidence-based feeding guideline. ICUs randomly allocated to the guideline group formed a local "intervention team", which actively implemented the guideline using standardized educational materials, a graphical feeding protocol, and live online education outreach meetings conducted by members of the study management committee. ICUs assigned to the control group remained unaware of the guideline content. All ICUs enrolled patients who were expected to stay in the ICU longer than seven days. The primary outcome was all-cause mortality within 28 days of enrollment.ResultsForty-eight ICUs were randomized to the guideline group and 49 to the control group. From March 2018 to July 2019, the guideline ICUs enrolled 1399 patients, and the control ICUs enrolled 1373 patients. Implementation of the guideline resulted in significantly earlier EN initiation (1.20 vs. 1.55 mean days to initiation of EN; difference - 0.40 [95% CI - 0.71 to - 0.09]; P = 0.01) and delayed PN initiation (1.29 vs. 0.80 mean days to start of PN; difference 1.06 [95% CI 0.44 to 1.67]; P = 0.001). There was no significant difference in 28-day mortality (14.2% vs. 15.2%; difference - 1.6% [95% CI - 4.3% to 1.2%]; P = 0.42) between groups.ConclusionsIn this large-scale, multicenter trial, active implementation of an evidence-based feeding guideline reduced the time to commencement of EN and overall PN use but did not translate to a reduction in mortality from critical illness.Trial registrationISRCTN, ISRCTN12233792 . Registered November 20th, 2017
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