Effects of blade geometry on cavitation and pressure fluctuations of tunnel thrusters

Compared with open propellers, tunnel thruster blades are more vulnerable to cavitation and local structure vibration problems because they are typically heavily loaded and subject to severe non-uniformity of inflow produced by the blunt gearbox. However, it seems that the simple 'flat plate' is still often used in designing the thruster blades. In this research, model tests and RANS simulations are carried out for three highly skewed thruster blades having different pitch and rake profiles to investigate the effects of blade geometry on cavitation and pressure fluctuations. The results indicate that the 'flat plate' blade is unfavorable for vibration excitation and unloading towards the tip is an effective way to reduce the fluctuating pressures

Investigation of the interaction between indigotin and two serum albumins by spectroscopic approaches

AbstractThe binding characteristics of indigotin with human serum albumin (HSA) and bovine serum albumin (BSA) have been investigated by various spectroscopic techniques. Spectroscopic analysis revealed that the quenching mechanism between indigotin and HSA/BSA belonged to the static quenching. The displacement experiments suggested that indigotin primarily bound to tryptophan residues on proteins within site I. The thermodynamic parameters indicated that the binding of indigotin–HSA/BSA mainly depended on the hydrophobic interaction. The binding distance of indigotin to HSA/BSA was evaluated. The results by synchronous fluorescence, three-dimensional fluorescence, Fourier Transform Infrared spectroscopy (FT-IR) and circular dichroism (CD) spectra showed that the conformation of proteins altered in the presence of indigotin

Information scrambling and entanglement in quantum approximate optimization algorithm circuits

Variational quantum algorithms, which consist of optimal parameterized quantum circuits, are promising for demonstrating quantum advantages in the noisy intermediate-scale quantum (NISQ) era. Apart from classical computational resources, different kinds of quantum resources have their contributions in the process of computing, such as information scrambling and entanglement. Characterizing the relation between complexity of specific problems and quantum resources consumed by solving these problems is helpful for us to understand the structure of VQAs in the context of quantum information processing. In this work, we focus on the quantum approximate optimization algorithm (QAOA), which aims to solve combinatorial optimization problems. We study information scrambling and entanglement in QAOA circuits respectively, and discover that for a harder problem, more quantum resource is required for the QAOA circuit to obtain the solution. We note that in the future, our results can be used to benchmark complexity of quantum many-body problems by information scrambling or entanglement accumulation in the computing process.Comment: 11 pages, 9 figures, Some minor correction

Synthesis of a Bi2O2CO3/ZnFe2O4 heterojunction with enhanced photocatalytic activity for visible light irradiation-induced NO removal

Although bismuth subcarbonate (Bi2O2CO3), a member of the Aurivillius-phase oxide family, is a promising photocatalyst for the removal of gaseous NO at parts-per-billion level, the large band gap of this material restricts its applications to the UV light region. The above problem can be mitigated by heterojunction fabrication, which not only broadens the light absorbance range, but also inhibits the recombination of photogenerated charge carriers. Herein, we implement this strategy to fabricate a novel Bi2O2CO3/ZnFe2O4 photocatalyst for NO removal under visible light irradiation and authenticate the formation of the above p-n heterojunction using an array of analytical techniques. Notably, the above composite showed activity superior to those of its individual constituents, and the underlying mechanisms of this activity enhancement were probed by density functional theory calculations and photocurrent measurements. Elevated electron/hole separation efficiency caused by the presence of an internal electric field at the Bi2O2CO3/ZnFe2O4 interface was identified as the main reason of the increased photocatalytic activity, with the main active species were determined as center dot O-2(-) and center dot OH by electron spin resonance spectroscopy. Finally, cytotoxicity testing proved the good biocompatibility of Bi2O2CO3/ZnFe2O4. Thus, this work presents deep insights into the preparation and use of a green p-n heterojunction catalyst in various applications

Diaqua­bis(pyrimidine-2-carboxylic acid-κ2 N,O)cobalt(II) dichloride

In the title salt, [Co(C5H4N2O2)2(H2O)2]Cl2, the CoII ion is located on an inversion center. It is chelated by two neutral pyrimidine-2-carboxylic acid molecules and is coordinated by two water mol­ecules in an octa­hedral coordination geometry. The cations and anions are linked via O—H⋯Cl hydrogen bonds into a layer structure; an intra­molecular O—H⋯N hydrogen bond connects the carboxylic acid group to the pyrimidine N atom