Effects of Design Parameters on Performance of Brushless Electrically Excited Synchronous Reluctance Generator

Permanent magnet synchronous generators, doubly fed induction generators, and traditional electrically excited synchronous generators are widely used for wind power applications, especially large offshore installations. In order to eliminate brushes and slip rings for improved reliability and maintenance-free operation, as well as to avoid costly permanent magnets, a novel brushless electrically excited synchronous reluctance generator having many outstanding advantages has been proposed in this paper. The fundamental operating principles, finite element analysis design studies and performance optimization aspects have been thoroughly investigated by simulations and experimentally under different loading conditions. The effects of different pole combinations and rotor dimensions on the magnetic coupling capacity of this machine have been specifically addressed and fully verified by off-line testing of the 6/2 pole and 8/4 pole prototypes with magnetic barrier reluctance rotor and a new hybrid cage rotor offering superior performance

A new fault diagnosis method using deep belief network and compressive sensing

Compressive sensing provides a new idea for machinery monitoring, which greatly reduces the burden on data transmission. After that, the compressed signal will be used for fault diagnosis by feature extraction and fault classification. However, traditional fault diagnosis heavily depends on the prior knowledge and requires a signal reconstruction which will cost great time consumption. For this problem, a deep belief network (DBN) is used here for fault detection directly on compressed signal. This is the first time DBN is combined with the compressive sensing. The PCA analysis shows that DBN has successfully separated different features. The DBN method which is tested on compressed gearbox signal, achieves 92.5 % accuracy for 25 % compressed signal. We compare the DBN on both compressed and reconstructed signal, and find that the DBN using compressed signal not only achieves better accuracies, but also costs less time when compression ratio is less than 0.35. Moreover, the results have been compared with other classification methods

Determination of non-freezing water in different nonfouling materials by differential scanning calorimetry

Nonfouling materials have attracted increasing interest for their excellent biocompatibility and low immunogenicity. Strong hydration is believed to be the key reason for their resisting capability to nonspecific protein adsorption. However, little attention has been paid to quantifying their strong water binding capacity. In this study, we synthesized four zwitterionic polymers, including poly(sulfobetaine methacrylate) (pSBMA), poly(carboxybetaine methacrylate) (pCBMA), poly(carboxybetaine acrylamide) (pCBAA) and poly(2-methacryloyloxyethyl phosphorylcholine) (pMPC), and compared non-freezing water of these zwitterionic polymers with typical antifouling polymer poly(ethylene glycol) (PEG) using differential scanning calorimetry (DSC). Non-freezing water of their monomers was also investigated. The non-freezing water of the polymers (per unit) is pMPC (10.7 ± 1.4) ≈ pCBAA (10.8 ± 1.5) &gt; pCBMA (9.0 ± 0.6) &gt; pSBMA (6.6 ± 0.4) &gt; PEG20000 (0.60 ± 0.04). Similar trend is observed for their monomers. For all studied zwitterionic materials, they showed higher binding capacity than PEG. We attribute the stronger hydration of zwitterionic polymers to their strong electrostatic interactions.</p

Daptomycin-biomineralized silver nanoparticles for enhanced photothermal therapy with anti-tumor effect

Silver nanoparticles as photothermal agents have the problems of low stability and low photothermal conversion efficiency. Amphiphilic daptomycin can improve the stability of silver nanoparticles, thereby improving their photothermal conversion efficiency. Herein, daptomycin-biomineralized silver nanoparticles (Dap-AgNPs) were prepared by reducing silver nitrate with sodium borohydride in the presence of daptomycin as a stabilizer and biomineralizer. The Dap-AgNPs had good solution stability and peroxidase-like activity. Furthermore, the photothermal conversion efficiency of the Dap-AgNPs was as high as 36.8%. The Dap-AgNPs displayed good photothermal stability under irradiation. More importantly, the Dap-AgNPs showed good cell compatibility with HeLa cells and HT-29 cells without irradiation by 808-nanometer near-infrared light at a concentration of 0.5 mM, and the cell viability was greater than 85.0%. However, the Dap-AgNPs displayed significant anti-tumor ability with irradiation by 808-nanometer near-infrared light, which was due to the increasing temperature of the culture medium caused by the Dap-AgNPs. In conclusion, Dap-AgNPs have potential applications as photothermal agents in the treatment of tumors.</p

Lentinan stabilized bimetallic PdPt₃ dendritic nanoparticles with enhanced oxidase-like property for L-cysteine detection

The development of nanozymes with enhanced catalytic activity has been drawing great interest. Lentinan with special structure may be used to prepare bimetallic nanomaterials to enhance their catalytic activity. Herein, lentinan stabilized PdPt3 dendritic nanoparticles (PdPt3-LNT NDs) were prepared through reduction of Na2PdCl4 and K2PtCl4 with a molar ratio of 1:3 using lentinan as a biological template. PdPt3-LNT NDs had dendritic shape with size of 10.76 ± 1.82 nm. PdPt3-LNT NDs had the hydrodynamic size about 25.7 nm and the zeta potential between −1.4 mV and − 4.9 mV at different pH. Furthermore, PdPt3-LNT NDs catalyzed 3,3′,5,5′-tetramethylbenzidine (TMB) to produce oxidized TMB, suggesting their oxidase-like property. The catalytic activity of PdPt3-LNT NDs was the highest when pH was 4 and the temperature was 40 °C. The catalytic mechanism was the generation of reactive oxygen species− from O2 catalyzed by PdPt3-LNT NDs. More importantly, L-cysteine detection method was set up based on the oxidase-like property of PdPt3-LNT NDs. This method had wide linear range for 0–200 μM and low detection limit for 3.099 μM. Taken together, PdPt3-LNT NDs have good potential applications in bio-related detection in the future.</p

Optimizing the Growth of Silage Maize by Adjusting Planting Density and Nitrogen Application Rate Based on Farmers’ Conventional Planting Habits

Silage maize is cultivated due to its high nutritional value as a forage. China’s recent agricultural policy promotes the popularization and cultivation of silage maize. The production of silage maize is affected by planting density and nitrogen application. Based on investigating the planting habits of local farmers, we adjusted the planting density and nitrogen application rate to optimize the growth of silage maize. This study was conducted to investigate the effects of planting density (65,000 plant ha−1 (D1), 80,000 plant ha−1 (D2), and 95,000 plant ha−1 (D3)) and nitrogen rate (150 kg ha−1 (N1), 230 kg ha−1 (N2), and 310 kg ha−1 (N3)) on growth, yield, and quality of silage maize using a two-factor random block design. Planting density and nitrogen fertilizer significantly affected plant height, stem diameter, leaf area index, crude protein, neutral detergent fiber, acid detergent fiber, and starch of silage maize. In summary, the combination of a planting density of 80,000 plants ha−1 and a nitrogen application rate of 310 kg ha−1 produced a higher crude protein and starch yield and better palatability and quality; this result can aid silage maize growth

Stable gold nanoflowers modified by zwitterionic sulfhydryl sulfobetaine for enhanced antitumor effiecieny

Gold nanoflowers are flower-like gold nanoparticles with high photothermal conversion efficiency. Unfortunately, many gold nanoflowers have complicated synthesis methods using toxicity molecules and lack colloidal stability. In this work, in order to improve the long-term colloidal stability of existing gold nanoflowers, sulfhydryl sulfobetaine (SB-SH) was modified on the surface of gold nanoflowers by S-Au bonds to produce SB-SH stabilized gold nanoflowers (SB-SH@AuNFs). SB-SH@AuNFs did not generate any precipitation within 24 h and had a high photothermal conversion efficiency at 38.9%. In addition, the relative cell viability of A549 cells was only 11% with 0.193 mM SB-SH@AuNFs under laser irradiation. More importantly, SB-SH@AuNFs had the best antitumor effect in vivo under 808 nm laser irradiation. Thus, stable SB-SH@AuNFs with high photothermal conversion efficient were synthesized by using zwitterionic molecules. The modification of gold nanoflowers using zwitterionic molecules here is a new method to improve the antitumor efficiency of noble metal photothermal agents

Layered sphere-shaped TiO2 capped with gold nanoparticles on structural defects and their catalysis of formaldehyde oxidation

We describe here a one-step method for the synthesis of Au/TiO2 nanosphere materials, which were formed by layered deposition of multiple anatase TiO2 nanosheets. The Au nanoparticles were stabilized by structural defects in each TiO2 nanosheet, including crystal steps and edges, thereby fixing the Au-TiO2 perimeter interface. Reactant transfer occurred along the gaps between these TiO2 nanosheet layers and in contact with catalytically active sites at the Au-TiO2 interface. The doped Au induced the formation of oxygen vacancies in the Au-TiO2 interface. Such vacancies are essential for generating active oxygen species (*O-) on the TiO2 surface and Ti3+ ions in bulk TiO2. These ions can then form Ti3+-O-Ti4+ species, which are known to enhance the catalytic activity of formaldehyde (HCHO) oxidation. These studies on structural and oxygen vacancy defects in Au/TiO2 samples provide a theoretical foundation for the catalytic mechanism of HCHO oxidation on oxide-supported Au materials. (C) 2015 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V