Adding nanoparticles can significantly improve the tribological properties of lubricants.However,there is a lack of understanding regarding the influence of nanoparticle shape on lubrication performance.In this work,t...Adding nanoparticles can significantly improve the tribological properties of lubricants.However,there is a lack of understanding regarding the influence of nanoparticle shape on lubrication performance.In this work,the influence of diamond nanoparticles(DNPs)on the tribological properties of lubricants is investigated through friction experiments.Additionally,the friction characteristics of lubricants regarding ellipsoidal particle shape are investigated using molecular dynamics(MD)simulations.The results show that DNPs can drastically lower the lubricant's friction coefficientμfrom 0.21 to 0.117.The shearing process reveals that as the aspect ratio(α)of the nanoparticles approaches 1.0,the friction performance improves,and wear on the wall diminishes.At the same time,the shape of the nanoparticles tends to be spherical.When 0.85≤α≤1.0,rolling is ellipsoidal particles'main form of motion,and the friction force changes according to a periodic sinusoidal law.In the range of 0.80≤α<0.85,ellipsoidal particles primarily exhibit sliding as the dominant movement mode.Asαdecreases within this range,the friction force progressively increases.The friction coefficientμcalculated through MD simulation is 0.128,which is consistent with the experimental data.展开更多
In order to improve the reliability of power supply,the sophisticated design of the structure of electric cable network has become an important issue for modern urban distribution networks.In this paper,an electric ca...In order to improve the reliability of power supply,the sophisticated design of the structure of electric cable network has become an important issue for modern urban distribution networks.In this paper,an electric cable path planning model based on heuristic optimization algorithm considering mixed-land scenario is proposed.Firstly,based on different land samples,the kernel density estimation(KDE)and the analytic hierarchy process(AHP)are used to estimate the construction cost of each unit grid,in order to construct the objective function of comprehensive investment for electric cable loop network.Then,the ant colony optimization(ACO)was improved in pheromone concentration,factor increment and search direction to accelerate the solving speed,and the cable path planning result with minimum construction cost is obtained.Finally,the feeder’s tie line of the cable loop network is planned by the genetic algorithm(GA)to achieve the minimum operating cost.In the case analysis,compared with the traditional method,not only the subjective factors in the process of investment estimation can be avoided,but also the speed of model solving and the quality of the optimal solution are improved.展开更多
Ginsenoside compound K(GCK), the main metabolite of protopanaxadiol constituents of Panax ginseng, easily produces alkali metal adduct ions during mass spectrometry particularly with lithium. Accordingly, we have deve...Ginsenoside compound K(GCK), the main metabolite of protopanaxadiol constituents of Panax ginseng, easily produces alkali metal adduct ions during mass spectrometry particularly with lithium. Accordingly, we have developed a rapid and sensitive liquid chromatography–tandem mass spectrometric method for analysis of GCK in human plasma based on formation of a lithium adduct. The analyte and paclitaxel(internal standard) were extracted from 50 m L human plasma using methyl tertbutyl ether. Chromatographic separation was performed on a Phenomenex Gemini C18 column(50 mm 2.0 mm; 5 μm) using stepwise gradient elution with acetonitrile–water and 0.2 mmol/L lithium carbonate at a flow rate of 0.5 m L/min. Detection was performed in the positive ion mode using multiple reaction monitoring of the transitions at m/z 629-449 for the GCK-lithium adduct and m/z 860-292 for the adduct of paclitaxel. The assay was linear in the concentration range 1.00–1000 ng/m L(r^2>40.9988)with intra- and inter-day precision of ±8.4% and accuracy in the range of 4.8% to 6.5%. Recovery,stability and matrix effects were all satisfactory. The method was successfully applied to a pharmacokinetic study involving administration of a single GCK 50 mg tablet to healthy Chinese volunteers.展开更多
To optimize both the mechanical and biological properties of titanium for biomedical implants,a highly flexible powder metallurgy approach is proposed to generate porous scaffolds with graded porosities and pore sizes...To optimize both the mechanical and biological properties of titanium for biomedical implants,a highly flexible powder metallurgy approach is proposed to generate porous scaffolds with graded porosities and pore sizes.Sugar pellets acting as space holders were compacted with titanium powder and then removed by dissolution in water before sintering.The morphology,pore structure,porosity and pore interconnectivity were observed by optical microscopy and SEM.The results show that the porous titanium has porosity levels and pore size gradients consistent with their design with gradual and smooth transitions at the interfaces between regions of differing porosities and/or pore sizes.Meanwhile,the porous titanium has high interconnectivity between pores and highly spherical pore shapes.In this article we show that this powder metallurgy processing technique,employing the novel sugar pellets as space-holders,can generate porous titanium foams with well-controlled graded porosities and pore sizes.This method has excellent potential for producing porous titanium structures for hard tissue engineering applications.展开更多
基金Supported by National Natural Science Foundation of China (Grant No.52275178)Fujian industry university cooperation project (Grant No.2020H6025)。
文摘Adding nanoparticles can significantly improve the tribological properties of lubricants.However,there is a lack of understanding regarding the influence of nanoparticle shape on lubrication performance.In this work,the influence of diamond nanoparticles(DNPs)on the tribological properties of lubricants is investigated through friction experiments.Additionally,the friction characteristics of lubricants regarding ellipsoidal particle shape are investigated using molecular dynamics(MD)simulations.The results show that DNPs can drastically lower the lubricant's friction coefficientμfrom 0.21 to 0.117.The shearing process reveals that as the aspect ratio(α)of the nanoparticles approaches 1.0,the friction performance improves,and wear on the wall diminishes.At the same time,the shape of the nanoparticles tends to be spherical.When 0.85≤α≤1.0,rolling is ellipsoidal particles'main form of motion,and the friction force changes according to a periodic sinusoidal law.In the range of 0.80≤α<0.85,ellipsoidal particles primarily exhibit sliding as the dominant movement mode.Asαdecreases within this range,the friction force progressively increases.The friction coefficientμcalculated through MD simulation is 0.128,which is consistent with the experimental data.
基金funded by the Science and Technology Project(Project No.kj2020-065)of State Grid Hebei Electric Power Co.,Ltd.
文摘In order to improve the reliability of power supply,the sophisticated design of the structure of electric cable network has become an important issue for modern urban distribution networks.In this paper,an electric cable path planning model based on heuristic optimization algorithm considering mixed-land scenario is proposed.Firstly,based on different land samples,the kernel density estimation(KDE)and the analytic hierarchy process(AHP)are used to estimate the construction cost of each unit grid,in order to construct the objective function of comprehensive investment for electric cable loop network.Then,the ant colony optimization(ACO)was improved in pheromone concentration,factor increment and search direction to accelerate the solving speed,and the cable path planning result with minimum construction cost is obtained.Finally,the feeder’s tie line of the cable loop network is planned by the genetic algorithm(GA)to achieve the minimum operating cost.In the case analysis,compared with the traditional method,not only the subjective factors in the process of investment estimation can be avoided,but also the speed of model solving and the quality of the optimal solution are improved.
文摘Ginsenoside compound K(GCK), the main metabolite of protopanaxadiol constituents of Panax ginseng, easily produces alkali metal adduct ions during mass spectrometry particularly with lithium. Accordingly, we have developed a rapid and sensitive liquid chromatography–tandem mass spectrometric method for analysis of GCK in human plasma based on formation of a lithium adduct. The analyte and paclitaxel(internal standard) were extracted from 50 m L human plasma using methyl tertbutyl ether. Chromatographic separation was performed on a Phenomenex Gemini C18 column(50 mm 2.0 mm; 5 μm) using stepwise gradient elution with acetonitrile–water and 0.2 mmol/L lithium carbonate at a flow rate of 0.5 m L/min. Detection was performed in the positive ion mode using multiple reaction monitoring of the transitions at m/z 629-449 for the GCK-lithium adduct and m/z 860-292 for the adduct of paclitaxel. The assay was linear in the concentration range 1.00–1000 ng/m L(r^2>40.9988)with intra- and inter-day precision of ±8.4% and accuracy in the range of 4.8% to 6.5%. Recovery,stability and matrix effects were all satisfactory. The method was successfully applied to a pharmacokinetic study involving administration of a single GCK 50 mg tablet to healthy Chinese volunteers.
基金the support of the ARC Research Hub for Advanced Manufacturing of Medical Devices(IH150100024)M.J.Bermingham acknowledges the support of the ARC Discovery Early Career Researcher Awards(DE160100260).
文摘To optimize both the mechanical and biological properties of titanium for biomedical implants,a highly flexible powder metallurgy approach is proposed to generate porous scaffolds with graded porosities and pore sizes.Sugar pellets acting as space holders were compacted with titanium powder and then removed by dissolution in water before sintering.The morphology,pore structure,porosity and pore interconnectivity were observed by optical microscopy and SEM.The results show that the porous titanium has porosity levels and pore size gradients consistent with their design with gradual and smooth transitions at the interfaces between regions of differing porosities and/or pore sizes.Meanwhile,the porous titanium has high interconnectivity between pores and highly spherical pore shapes.In this article we show that this powder metallurgy processing technique,employing the novel sugar pellets as space-holders,can generate porous titanium foams with well-controlled graded porosities and pore sizes.This method has excellent potential for producing porous titanium structures for hard tissue engineering applications.
