Time-frequency feature extraction from multiple impulse source signal of reciprocating compressor based on local frequency

Vibration signals generated by reciprocating compressor present a multiple impulse source property, which is typical non-stationary. For this kind of signal, time-frequency analysis techniques, such as STFT, WVT, WT and HHT, represent some limitations. To alleviate this problem, a novel concept of local frequency (LF) is proposed in the paper. Based on the concept, a time-frequency distribution algorithm is established. Some non-stationary simulation signals, including multi-harmonic signal, FM signal and multiple impulse source signal, are investigated to identify the feasibility and effectiveness of the novel time-frequency analysis technique. Compared with WVT, WT and HHT, time-frequency analysis based on LF represents a higher resolution and more useful information. Moreover, the proposed approach is applied to the fault feature extraction of reciprocating compressor gas valve vibration signal in normal valve state and gap valve state. The results indicate the superiority of proposed approach in extracting time-frequency features from multiple impulse source signal of reciprocating compressor, which obtains a more precise result than WVT, WT and HHT. So it can provide an effective basis to fault diagnosis of reciprocating compressor

Does Graph Distillation See Like Vision Dataset Counterpart?

Training on large-scale graphs has achieved remarkable results in graph representation learning, but its cost and storage have attracted increasing concerns. Existing graph condensation methods primarily focus on optimizing the feature matrices of condensed graphs while overlooking the impact of the structure information from the original graphs. To investigate the impact of the structure information, we conduct analysis from the spectral domain and empirically identify substantial Laplacian Energy Distribution (LED) shifts in previous works. Such shifts lead to poor performance in cross-architecture generalization and specific tasks, including anomaly detection and link prediction. In this paper, we propose a novel Structure-broadcasting Graph Dataset Distillation (SGDD) scheme for broadcasting the original structure information to the generation of the synthetic one, which explicitly prevents overlooking the original structure information. Theoretically, the synthetic graphs by SGDD are expected to have smaller LED shifts than previous works, leading to superior performance in both cross-architecture settings and specific tasks. We validate the proposed SGDD across 9 datasets and achieve state-of-the-art results on all of them: for example, on the YelpChi dataset, our approach maintains 98.6% test accuracy of training on the original graph dataset with 1,000 times saving on the scale of the graph. Moreover, we empirically evaluate there exist 17.6% ~ 31.4% reductions in LED shift crossing 9 datasets. Extensive experiments and analysis verify the effectiveness and necessity of the proposed designs. The code is available in the GitHub repository: https://github.com/RingBDStack/SGDD.Comment: Accepted by NeurIPS 202

Diaqua­bis­(1-methyl-1H-imidazole-κN 3)bis­[2-(naphthalen-1-yl)acetato-κO]cobalt(II)

In the title compound, [Co(C12H9O2)2(C4H6N2)2(H2O)2], the CoII ion is located on an inversion centre and displays a distorted octa­hedral coordination geometry. Two O atoms from two water mol­ecules and two carboxyl­ate O atoms from two 2-(naphthalen-1-yl)acetate ligands are in the equatorial plane and two N atoms from two 1-methyl-1H-imidazole ligands are in the axial positions. The structure is stabilized by intra­molecular O—H⋯O hydrogen bonds. Inter­molecular O—H⋯O hydrogen bonds link the complex mol­ecules into chains along [100]

Bis­(2-methyl-1H-imidazole-κN 3)bis[2-(naphthalen-2-yl)acetato-κO]copper(II)

In the crystal structure of the title compound, [Cu(C12H9O2)2(C4H6N2)2], the Cu(II) cations are square-planar coordinated by two 1-naphthyl­acetate anions and two 2-methyl-imidazole ligands into discrete complexes that are located on centres of inversion. These complexes are linked into chains parallel to [010] by inter­molecular N—H⋯O hydrogen bonding between the N—H H atom of the 2-methyl-imidazole ligands and the carboxyl­ate O atoms that are not involved in metal coordination

Pyrrolidin-1-ium 2-(naphthalen-1-yl)acetate–2-(naphthalen-1-yl)acetic acid (1/1)

In the title compound, C4H10N+·C12H9O2 −·C12H10O2, the pyrrolidine ring adopts an envelope conformation and the dihedral angle between the planes of the two naphthalene ring systems is 8.34 (10)°. The crystal structure is stabilized by O—H⋯O and N—H⋯O hydrogen bonds

A one-dimensional ladder-like coordination polymer: poly[[hexa­aqua­bis(μ-5-nitro­benzene-1,3-dicarboxyl­ato-κ3 O,O′,O′′)(μ-oxalato-κ4 O,O′:O′′,O′′′)diyttrium(III)] trihydrate]

In the crystal structure of the title one-dimensional coordination polymer, [Y2(C8H3NO6)2(C2O4)(H2O)6]·3H2O, each YIII ion is bridged to its neighbours by two 5-nitro­benzene-1,3-dicarboxyl­ate (nbdc) dianions and one oxalate dianion (located on an inversion centre) to form a ladder-like polymeric structure. The two carboxylate groups of nbdc assume different modes of coordination, one is chelating whereas the other is monodentate. Three water mol­ecules coordinate to the YIII ion to complete an eight-coordinate distorted dodecahedral geometry. The ladder-like polymers are assembled together by hydrogen bonding and π–π stacking [centrio–centriod distance = 3.819 (9) Å] in the crystal structure

iRGD-modified Lipid-polymer Hybrid Nanoparticles Loaded With Isoliquiritigenin To Enhance Anti-breast Cancer Effect And Tumor-targeting Ability

published_or_final_versio

Bis(1H-benzimidazole-κN 3)bis­[2-(naphthalen-1-yl)acetato-κ2 O,O′]nickel(II) monohydrate

In the title compound, [Ni(C12H9O2)2(C7H6N2)2]·H2O, The NiII cation is located on a twofold rotation axis and is six-coordinated in a distorted NiN2O4 octa­hedral geometry. The asymmetric unit consists of a nickel(II) ion, one 2-(naphthalen-1-yl)acetate anion, a neutral benzotriazole ligand and one half of a lattice water mol­ecule. The crystal packing is stabilized by O—H⋯O and N—H⋯O hydrogen bonds. The title compound is isotypic with its CdII analogue

Bis(1-methyl-1H-imidazole-κN 3)bis­[2-(naphthalen-1-yl)acetato-κO]copper(II) monohydrate

In the crystal structure of the title compound, [Cu(C12H9O2)2(C4H6N2)2]·H2O, the CuII atom is coordinated by two 2-(naphthalen-1-yl)acetate anions and two 1-methyl­imidazole ligands, giving monomeric complexes with a square-planar coordination environment. Two complex mol­ecules and two water mol­ecules form a centrosymmetric ring system via O—H⋯O hydrogen bonds

Banna Virus, China, 1987–2007

Banna viruses (BAVs) have been isolated from pigs, cattle, ticks, mosquitoes, and human encephalitis patients. We isolated and analyzed 20 BAVs newly isolated in China; this finding extends the distribution of BAVs from tropical zone to north temperate climates and demonstrate regional variations in BAV phylogeny and mosquito species possibly involved in BAV transmission