(2,2′-Bipyridine-6,6′-dicarboxyl­ato-κ3 N,N′,O 6)(6′-carb­oxy-2,2′-bipyridine-6-carboxyl­ato-κ3 N,N′,O 6)cobalt(III)

The CoIII atom in the title compound, [Co(C12H6N2O4)(C12H7N2O4)], is six-coordinated in a distorted octa­hedral geometry by four N atoms and two O atoms of the chelating 2,2′-bipyridine-6,6′-dicarboxyl­ate and 6′-carb­oxy-2,2′-bipyridine-6-carboxyl­ate ligands. Intermolecular O—H⋯O hydrogen bonds and face-to-face π-stacking inter­actions [centroid–centroid distance = 3.6352 (16) Å] between inversion-related pyridine rings link adjacent mononuclear units into a two-dimensional supra­molecular structure, and several inter­molecular C—H⋯O inter­actions are also observed

(2,2′-Bipyridine-6,6′-dicarboxyl­ato-κ3 N,N′,O 6)(6′-carb­oxy-2,2′-bipyridine-6-carboxyl­ato-κ3 N,N′,O 6)rhodium(III)

The RhIII ion in the title compound, [Rh(C12H6N2O4)(C12H7N2O4)], is coordinated by four N atoms and two O atoms from two chelating ligands L and HL (H2L = 2,2′-bipyridine-6,6′-dicarb­oxy­lic acid) to form a distorted octa­hedral geometry. Face-to-face π-stacking inter­actions are observed between inversion-related pyridine rings, with a centroid-to-centroid distance of 3.581 (1) Å [the perpendicular distance between the rings is 3.3980 (7) Å]. Inter­molecular O—H⋯O hydrogen bonds link adjacent mol­ecules into one-dimensional supra­molecular chains along the c axis, while several inter­molecular C—H⋯O inter­actions are also observed

Bis(6′-carb­oxy-2,2′-bipyridine-6-carboxyl­ato-κ3 N,N′,O 6)nickel(II) tetra­hydrate

In the title compound, [Ni(C12H7N2O4)2]·4H2O, the Ni atom is located at the centre of a distorted octa­hedron, formed by four N atoms and two O atoms from the same two tridentating chelated 6-carb­oxy-2,2′-bipyridine-6′-carboxyl­ate (L) ligands. Face-to-face π-stacking inter­actions between inversion-related pyridine rings with centroid–centroid distances of 3.548 (3) and 3.662 (3) Å (perpendicular distances between the respective rings are 3.314 and 3.438 Å) are found. Inter­molecular O—H⋯O hydrogen bonds between water mol­ecules and L ligands form R 5 3(10), R 6 5(14) and R 5 5(12) rings and also a centrosymmetric cage-like unit of water mol­ecules, which link eight adjacent NiII centers, forming a three-dimensional framework

Combined study of the ground and excited states in the transformation of nanodiamonds into carbon onions by electron energy-loss spectroscopy

The electron momentum density and sp(2)/sp(3) ratio of carbon materials in the thermal transformation of detonation nanodiamonds (ND) into carbon nano-onions are systematically studied by electron energy-loss spectroscopy (EELS). Electron energy-loss near-edge structures of the carbon K-ionization in the electron energy-loss spectroscopy are measured to determine the sp(2) content of the ND-derived samples. We use the method developed by Titantah and Lamoen, which is based on the ability to isolate the pi* spectrum and has been shown to give reliable and accurate results. Compton profiles (CPs) of the ND-derived carbon materials are obtained by performing EELS on the electron Compton scattering region. The amplitude of the CPs at zero momentum increases with increasing annealing temperature above 500 degrees C. The dramatic changes occur in the temperature range of 900-1300 degrees C, which indicates that the graphitization process mainly occurs in this annealing temperature region. Our results complement the previous work on the thermal transformation of ND-derived carbon onions and provide deeper insight into the evolution of the electronic properties in the graphitization process

Facile Syntheses of Cucurbit[6]uril-Anchored Polymers and Their Noncovalent Modification

The general strategy for facile synthesis of Cucurbit[6]­uril- (CB[6]-) anchored polymers without the functionalization of CB[6] was presented. The acrylamide as a typical monomer was used to synthesize a series of CB[6]-anchored polyacrylamides (CB[6]-PAM) using potassium persulfateas as initiator and oxidant. The CB[6]-PAM samples were characterized by ¹H NMR, ¹³C NMR, HMQC, FTIR, and TGA. It was found that the composition and chain microstructure of CB[6]-PAM polymers could be tunable by changing the content of potassium persulfate, CB[6] and acrylamide. In addition, CB[6]-PAM could be assembled into nanosized vesicles, which were confirmed by TEM, AFM, and SEM measurements. By taking advantage of the exceptional binding affinity of the CB[6], the CB[6]-PAM could be modified with butyl amine hydrochloride. The result makes the CB[6]-anchored polymer potentially useful in many applications. Furthermore, this synthetic approach could be extend to CB[6]-anchored polymers with two different chains. As a typical example, CB[6]-anchored poly­(4-vinylbenzylamine hydrochloride salt) and polyacrylamide was synthesized successfully

Real-Time Detection of Slug Flow in Subsea Pipelines by Embedding a Yolo Object Detection Algorithm into Jetson Nano

In the multiple-phase pipelines in terms of the subsea oil and gas industry, the occurrence of slug flow would cause damage to the pipelines and related equipment. Therefore, it is very necessary to develop a real-time and high-precision slug flow identification technology. In this study, the Yolo object detection algorithm and embedded deployment are applied initially to slug flow identification. The annotated slug flow images are used to train seven models in Yolov5 and Yolov3. The high-precision detection of the gas slug and dense bubbles in the slug flow image in the vertical pipe is realized, and the issue that the gas slug cannot be fully detected due to being blocked by dense bubbles is solved. After model performance analysis, Yolov5n is verified to have the strongest comprehensive detection performance, during which, mAP0.5 is 93.5%, mAP0.5:0.95 is 65.1%, and comprehensive mAP (cmAP) is 67.94%; meanwhile, the volume of parameters and Flops are only 1,761,871 and 4.1 G. Then, the applicability of Yolov5n under different environmental conditions, such as different brightness and adding random obstructions, is analyzed. Finally, the trained Yolov5n is deployed to the Jetson Nano embedded device (NVIDIA, Santa Clara, CA, USA), and TensorRT is used to accelerate the inference process of the model. The inference speed of the slug flow image is about five times of the original, and the FPS has increased from 16.7 to 83.3

Structural Distortion of g-C₃N₄ Induced by N-Defects for Enhanced Photocatalytic Hydrogen Evolution

Hydrogen evolution by photocatalytic technology has been one of the most promising and attractive solutions, and can harvest and convert the abundant solar energy into green, renewable hydrogen energy. As a new kind of photocatalytic material, graphitic carbon nitride (g-C3N4) has drawn much attention in photocataluytic H2 production due to its visible light response, ease of preparation and good stability. For a higher photocatalyic performance, N defects were introduced in to the traditional g-C3N4 in this work. The existence of N defects was proved by adequate material characterization. Significantly, a new absorption region at around 500 nm of N-deficient g-C3N4 appeared, revealing the exciting n-π* transition of lone pair electrons. The photocatalytic H2 production performance of N-deficient g-C3N4 was increased by 5.8 times. The enhanced photocatalytic performance of N-deficient g-C3N4 was attributed to the enhanced visible light absorption, as well as the promoted separation of photo-generated carries and increased specific surface area