781 research outputs found
2-(2-Furylmethylaminomethyl)-4-sulfanylphenol
In the title compound, C12H13NO2S, the dihedral angle between the furan and benzene rings is 62.2 (2)° and an intramolecular O—H⋯N hydrogen bond is formed. In the crystal, molecules are linked by weak intermolecular N—H⋯S hydrogen bonds
Benzimidazolium 2-(2,4-dichlorophenoxy)acetate monohydrate
In the crystal of the title hydrated molecular salt, C7H7N2
+·C8H5Cl2O3·H2O, the components interact by way of N—H⋯O and O—H⋯O hydrogen bonds, leading to chains propagating in [100]
Bis(2-cyclohexyliminomethyl-4,6-disulfanylphenolato)zinc(II)
In the title complex, [Zn(C13H16NOS2)2], the ZnII ion is four-coordinated by two N,O-bidentate Schiff base ligands, resulting in a distorted trans-ZnN2O2 square-planar geometry for the metal ion
Noise suppression of on-chip mechanical resonators by chaotic coherent feedback
We propose a method to decouple the nanomechanical resonator in
optomechanical systems from the environmental noise by introducing a chaotic
coherent feedback loop. We find that the chaotic controller in the feedback
loop can modulate the dynamics of the controlled optomechanical system and
induce a broadband response of the mechanical mode. This broadband response of
the mechanical mode will cut off the coupling between the mechanical mode and
the environment and thus suppress the environmental noise of the mechanical
modes. As an application, we use the protected optomechanical system to act as
a quantum memory. It's shown that the noise-decoupled optomechanical quantum
memory is efficient for storing information transferred from coherent or
squeezed light
Bis(2-chloro-1,10-phenanthroline-κ2 N,N′)(thiocyanato-κN)zinc (2-chloro-1,10-phenanthroline-κ2 N,N′)tris(thiocyanato-κN)zincate
The asymmetric unit of the title compound, [Zn(NCS)(C12H7ClN2)2][Zn(NCS)3(C12H7ClN2)], contains two cations and two anions. In the cations, the ZnII ions have distorted trigonal–bipyramidal environments formed by four N atoms from two 2-chloro-1,10-phenanthroline (cphen) ligands and one N atom from a thiocyanate ligand. The ZnII atoms in the complex anions also have distorted trigonal–bipyramidal environments, formed by two N atoms from a cphen ligand and three N atoms from three thiocyanato ligands. The crystal packing exhibits π–π interactions between the rings of the cphen ligands [shortest centroid–centroid distance = 3.586 (5) Å] and short intermolecular S⋯Cl [3.395 (5) Å] and S⋯S [3.440 (4) Å] contacts
Disentangled Generative Causal Representation Learning
This paper proposes a Disentangled gEnerative cAusal Representation (DEAR)
learning method. Unlike existing disentanglement methods that enforce
independence of the latent variables, we consider the general case where the
underlying factors of interests can be causally correlated. We show that
previous methods with independent priors fail to disentangle causally
correlated factors. Motivated by this finding, we propose a new disentangled
learning method called DEAR that enables causal controllable generation and
causal representation learning. The key ingredient of this new formulation is
to use a structural causal model (SCM) as the prior for a bidirectional
generative model. The prior is then trained jointly with a generator and an
encoder using a suitable GAN loss incorporated with supervision. We provide
theoretical justification on the identifiability and asymptotic consistency of
the proposed method, which guarantees disentangled causal representation
learning under appropriate conditions. We conduct extensive experiments on both
synthesized and real data sets to demonstrate the effectiveness of DEAR in
causal controllable generation, and the benefits of the learned representations
for downstream tasks in terms of sample efficiency and distributional
robustness
Optimal Sample Selection Through Uncertainty Estimation and Its Application in Deep Learning
Modern deep learning heavily relies on large labeled datasets, which often
comse with high costs in terms of both manual labeling and computational
resources. To mitigate these challenges, researchers have explored the use of
informative subset selection techniques, including coreset selection and active
learning. Specifically, coreset selection involves sampling data with both
input (\bx) and output (\by), active learning focuses solely on the input
data (\bx).
In this study, we present a theoretically optimal solution for addressing
both coreset selection and active learning within the context of linear softmax
regression. Our proposed method, COPS (unCertainty based OPtimal Sub-sampling),
is designed to minimize the expected loss of a model trained on subsampled
data. Unlike existing approaches that rely on explicit calculations of the
inverse covariance matrix, which are not easily applicable to deep learning
scenarios, COPS leverages the model's logits to estimate the sampling ratio.
This sampling ratio is closely associated with model uncertainty and can be
effectively applied to deep learning tasks. Furthermore, we address the
challenge of model sensitivity to misspecification by incorporating a
down-weighting approach for low-density samples, drawing inspiration from
previous works.
To assess the effectiveness of our proposed method, we conducted extensive
empirical experiments using deep neural networks on benchmark datasets. The
results consistently showcase the superior performance of COPS compared to
baseline methods, reaffirming its efficacy
{4-[(Diphenylphosphino)methylamino]pyridinium-κP}bis(nitrato-κO)silver(I)
In the title mononuclear complex, [Ag(C18H18N2P)(NO3)2], the metal centre is coordinated in a slightly distorted trigonal–planar geometry by the P atom of the phosphine ligand and the O atoms of the two monodentate nitrate anions. In the crystal structure, complex molecules are connected by intermolecular N—H⋯O hydrogen bonds, forming chains running parallel to the b axis
Graphene Field-Effect Transistor for Terahertz Modulation
The real-world applications of terahertz (THz) technology necessitate versatile adaptive optical components, for example, modulators. In this chapter, we begin with a brief review on different techniques for THz modulation. After that, we introduce the extraordinary features of graphene along with its advantages and disadvantages as channel materials for field effect transistor (FET). We then discuss two types of graphene FET-based THz modulators, one is rigid and another is flexible. The feasibility of the high-quality THz modulators with different graphene FET structures has been successfully demonstrated. It is observed that by tuning the carrier concentration of graphene by electrical gating, the THz modulation can be obtained with relatively large modulation depth, broad width band, and moderate speed. This chapter helps the reader in obtaining guidelines for the proper choice of a specific structure for THz modulator with graphene FET
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