293 research outputs found
Adding an extra condition: a general method to design double freeform-surface lens for LED uniform illumination
Comparative Safety Analysis of Accelerator Driven Subcritical Systems and Critical Nuclear Energy Systems
The accelerator driven subcritical system (ADS) has been chosen as one of the best candidates for Generation IV nuclear energy systems which could not only produce clean energy but also incinerate nuclear waste. The transient characteristics and operation principles of ADS are significantly different from those of the critical nuclear energy system (CNES). In this work, the safety characteristics of ADS are analyzed and compared with CNES by a developed neutronics and thermal-hydraulics coupled code named ARTAP. Three typical accidents are carried out in both ADS and CNES, including reactivity insertion, loss of flow, and loss of heat sink. The comparison results show that the power and the temperatures of fuel, cladding, and coolant of the CNES reactor are much higher than those of the ADS reactor during the reactivity insertion accident, which means ADS has a better safety advantage than CNES. However, due to the subcriticality of the ADS core and its low sensitivity to negative reactivity feedback, the simulation results indicate that the inherent safety characteristics of CNES are better than those of ADS under loss of flow accident, and the protection system of ADS would be quickly activated to achieve an emergency shutdown after the accident occurs. For the loss of heat sink, it is found that the peak temperatures of the cladding in the ADS and CNES reactors are lower than the safety limit, which imply these two reactors have good safety performance against loss of heat sink accidents
Effects of Different Enzyme Combination and Dissociation‐Time on the Protoplast Isolation of Alfalfa
Anomalous Hall magnetoresistance in a ferromagnet
The anomalous Hall effect, observed in conducting ferromagnets with broken
time-reversal symmetry, offers the possibility to couple spin and orbital
degrees of freedom of electrons in ferromagnets. In addition to charge, the
anomalous Hall effect also leads to spin accumulation at the surfaces
perpendicular to both the current and magnetization direction. Here we
experimentally demonstrate that the spin accumulation, subsequent spin
backflow, and spin-charge conversion can give rise to a different type of spin
current related magnetoresistance, dubbed here as the anomalous Hall
magnetoresistance, which has the same angular dependence as the recently
discovered spin Hall magnetoresistance. The anomalous Hall magnetoresistance is
observed in four types of samples: co-sputtered (Fe1-xMnx)0.6Pt0.4, Fe1-xMnx
and Pt multilayer, Fe1-xMnx with x = 0.17 to 0.65 and Fe, and analyzed using
the drift-diffusion model. Our results provide an alternative route to study
charge-spin conversion in ferromagnets and to exploit it for potential
spintronic applications
One-Step Leapfrog LOD-BOR-FDTD Algorithm with CPML Implementation
An unconditionally stable one-step leapfrog locally one-dimensional finite-difference time-domain (LOD-FDTD) algorithm towards body of revolution (BOR) is presented. The equations of the proposed algorithm are obtained by the algebraic manipulation of those used in the conventional LOD-BOR-FDTD algorithm. The equations for z-direction electric and magnetic fields in the proposed algorithm should be treated specially. The new algorithm obtains a higher computational efficiency while preserving the properties of the conventional LOD-BOR-FDTD algorithm. Moreover, the convolutional perfectly matched layer (CPML) is introduced into the one-step leapfrog LOD-BOR-FDTD algorithm. The equation of the one-step leapfrog CPML is concise. Numerical results show that its reflection error is small. It can be concluded that the similar CPML scheme can also be easily applied to the one-step leapfrog LOD-FDTD algorithm in the Cartesian coordinate system
Imprinting and Promoter Usage of Insulin-Like Growth Factor II in Twin Discordant Placenta
Case reports from infant twins suggest that abnormal genomic imprinting may be one of the important causes of twin discordance, but it is unknown whether abnormal genomic imprinting occurs in the placenta. Therefore, we sought to determine the relationship between the imprinting of insulin-like growth factor II (IGF-II) in placenta and twin discordance. We analyzed the imprinting and promoter usage of IGF-II in placenta of normal twins (T0 group), weight discordance (T1 group), and phenotype discordance (T2 group). We found the incidence of loss of imprinting (LOI) for IGF-II was higher in the T2 group than that in the T0 and T1 groups, while there was no difference between T0 and T1 groups. The transcripts of promoter 3 were lower in the T2 group than in the T0 and T1 groups, and lower in the twin placenta with LOI than in those with normal imprinting. Our findings indicate that the promoter 3 specific LOI of the IGF-II gene may be closely related with phenotype discordance, not weight discordance
VDialogUE: A Unified Evaluation Benchmark for Visually-grounded Dialogue
Visually-grounded dialog systems, which integrate multiple modes of
communication such as text and visual inputs, have become an increasingly
popular area of investigation. However, the absence of a standardized
evaluation framework poses a challenge in assessing the development of this
field. To this end, we propose \textbf{VDialogUE}, a \textbf{V}isually-grounded
\textbf{Dialog}ue benchmark for \textbf{U}nified \textbf{E}valuation. It
defines five core multi-modal dialogue tasks and covers six datasets.
Furthermore, in order to provide a comprehensive assessment of the model's
performance across all tasks, we developed a novel evaluation metric called
VDscore, which is based on the Analytic Hierarchy Process~(AHP) method.
Additionally, we present a straightforward yet efficient baseline model, named
\textbf{VISIT}~(\textbf{VIS}ually-grounded d\textbf{I}alog
\textbf{T}ransformer), to promote the advancement of general multi-modal
dialogue systems. It progressively builds its multi-modal foundation and
dialogue capability via a two-stage pre-training strategy.
We believe that the VDialogUE benchmark, along with the evaluation scripts
and our baseline models, will accelerate the development of visually-grounded
dialog systems and lead to the development of more sophisticated and effective
pre-trained models
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