1,653 research outputs found
Poly[[diaquabis(μ2-isonicotinato-κ2 N:O)bis(μ3-isonicotinato-κ3 N:O:O′)neodymium(III)disilver(I)] nitrate monohydrate]
In the title complex, {[Ag2Nd(C6H4NO2)4(H2O)2]NO3·H2O}n, the NdIII ion is coordinated by eight O atoms from six isonicotinate ligands and two water molecules in a distorted square antiprismatic geometry. Each AgI ion is coordinated by two N atoms from two different isonicotinate ligands. The crystal structure exhibits a two-dimensional heterometallic polymeric layer. O—H⋯O hydrogen bonds involving the coordinated and uncoordinated water molecules and intralayer π–π interactions between the pyridine rings [centroid–centroid distances = 3.571 (2) and 3.569 (2) Å] are observed. Each layer interacts with two neighboring ones via Ag⋯O(H2O) contacts and interlayer π–π interactions [centroid–centroid distances = 3.479 (3) to 3.530 (3) Å], leading to a three-dimensional supramolecular network
Poly[diaquabis(μ3-1H-benzimidazole-5,6-dicarboxylato-κ4 N 3:O 5,O 5′:O 6)bis(μ2-1H,3H-benzimidazolium-5,6-dicarboxylato-κ3 O 5,O 5′:O 6)digadolinium(III)]
In the title complex, [Gd2(C9H4N2O4)2(C9H5N2O4)2(H2O)2]n, two of the benzimidazole-5,6-dicarboxylate ligands are protonated at the imidazole groups. Each GdIII ion is coordinated by six O atoms and one N atom from five ligands and one water molecule, displaying a distorted bicapped trigonal-prismatic geometry. The GdIII ions are linked by the carboxylate groups and imidazole N atoms, forming a layer parallel to (001). These layers are further connected by O—H⋯O and N—H⋯O hydrogen bonds into a three-dimensional supramolecular network
Hemi(4,4′-bipyridinium) hexafluoridophosphate bis(4-aminobenzoic acid) 4,4′-bipyridine monohydrate
In the title compound, 0.5C10H10N2
2+·PF6
−·C10H8N2·2C7H7NO2·H2O, the cation is located on a center of symmetry. The crystal structure is determined by a complex three-dimensional network of intermolecular O—H⋯O, O—H⋯N, N—H⋯N and N—H⋯F hydrogen bonds. π–π stacking interactions between neighboring pyridyl rings are also present; the centroid–centroid distance is 3.643 (5) Å. The hexafluoridophosphate anion is disordered over two positions with site-occupancy factors of ca 0.6 and 0.4
Poly[[aqua(μ2-oxalato)(μ2-2-oxidopyridinium-3-carboxylato)dysprosium(III)] monohydrate]
In the title complex, {[Dy(C6H4NO3)(C2O4)(H2O)]·H2O}n, the DyIII ion is coordinated by seven O atoms from two 2-oxidopyridinium-3-carboxylate ligands, two oxalate ligands and one water molecule, displaying a distorted bicapped trigonal-prismatic geometry. The carboxylate groups of the 2-oxidopyridinium-3-carboxylate and oxalate ligands link dysprosium metal centres, forming layers parallel to (100). These layers are further connected by intermolecular O—H⋯O hydrogen-bonding interactions involving the coordinated water molecules, forming a three-dimensional supramolecular network. The uncoordinated water molecule is involved in N—H⋯O and O—H⋯O hydrogen-bonding interactions within the layer
tert-Butyl N-(4-hydroxybenzyl)-N-[4-(prop-2-ynyloxy)benzyl]carbamate
In the crystal structure of the title compound, C22H25NO4, intermolecular O—H⋯O hydrogen bonds involving the hydroxy group of the 4-(amimomethyl)phenol fragment and the C=O group connect the molecules into infinite chains along the c axis. Two C atoms of the propyne group are disordered over two sites with occupancy factors of 0.53 (2) and 0.47 (2)
Correction: Magnetoconductance modulations due to interlayer tunneling in radial superlattices
Correction for ‘Magnetoconductance modulations due to interlayer tunneling in radial superlattices’ by Yu-Jie Zhong et al., Nanoscale Horiz., 2022, 7, 168–173, https://doi.org/10.1039/D1NH00449B
Dissipation Theory-Based Ecological Protection and Restoration Scheme Construction for Reclamation Projects and Adjacent Marine Ecosystems.
According to the 2017 results of the Special Inspector of Sea Reclamation, a substantial number of idle reclamation zones existed in 11 provinces (cities) along the coast of China. To improve the protection level of coastal wetlands and strictly control reclamation activities, it is necessary to carry out ecological restoration of reclamation projects and adjacent marine ecosystems. The characteristics of Guanghai Bay and its reclamation project are typical in China’s coastal areas, making it an optimal representative site for this study. The dissipative structure and entropy theory was used to analyze ecological problems and environmental threats. The analytic hierarchy process was applied to determine the order of the negative entropy flow importance. The entropy increase and decrease mechanism was used to determine an ecological protection and restoration scheme for the reclamation, including the reclamation of wetland resource restoration, shoreline landscape restoration, environmental pollution control, and marine biological resource restoration. Finally, based on system logic, a typical ecological restoration system was constructed east of Guanghai Bay, with the mangrove wetland area as the model in the north and the artificial sandbeach recreation area as the focus in the south
Environmental Sound Recognition Using Time-Frequency Intersection Patterns
Environmental sound recognition is an important function of robots and intelligent computer systems. In this research, we use a multistage perceptron neural network system for environmental sound recognition. The input data is a combination of time-variance pattern of instantaneous powers and frequency-variance pattern with instantaneous spectrum at the power peak, referred to as a time-frequency intersection pattern. Spectra of many environmental sounds change more slowly than those of speech or voice, so the intersectional time-frequency pattern will preserve the major features of environmental sounds but with drastically reduced data requirements. Two experiments were conducted using an original database and an open database created by the RWCP project. The recognition rate for 20 kinds of environmental sounds was 92%. The recognition rate of the new method was about 12% higher than methods using only an instantaneous spectrum. The results are also comparable with HMM-based methods, although those methods need to treat the time variance of an input vector series with more complicated computations
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