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Review on the Fabrication of Surface Functional Structures for Enhancing Bioactivity of Titanium and Titanium Alloy Implants
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作者 Heng Tang Jiaxiang Xu +4 位作者 Bin Guo Yansong Xie Yalong Sun Yanjun Lu Yong Tang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2024年第4期23-49,共27页
Titanium and its alloys have been widely applied in many biomedical fields because of its excellent mechanical properties,corrosion resistance and good biocompatibility.However,problems such as rejection,shedding and ... Titanium and its alloys have been widely applied in many biomedical fields because of its excellent mechanical properties,corrosion resistance and good biocompatibility.However,problems such as rejection,shedding and infection will occur after titanium alloy implantation due to the low biological activity of titanium alloy surface.The structures with specific functions,which can enhance osseointegration and antibacterial properties,are fabricated on the surface of titanium implants to improve the biological activity between the titanium implants and human tissues.This paper presents a comprehensive review of recent developments and applications of surface functional structure in titanium and titanium alloy implants.The applications of surface functional structure on different titanium and titanium alloy implants are introduced,and their manufacturing technologies are summarized and compared.Furthermore,the fabrication of various surface functional structures used for titanium and titanium alloy implants is reviewed and analyzed in detail.Finally,the challenges affecting the development of surface functional structures applied in titanium and titanium alloy implants are outlined,and recommendations for future research are presented. 展开更多
关键词 surface functional structure Titanium implant Manufacturing technology Bioactivity
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Crustal and uppermost mantle structure of the northeastern Qinghai-Xizang Plateau from joint inversion of surface wave dispersions and receiver functions with P velocity constraints
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作者 Pei Zhang Xiaodong Song +2 位作者 Jiangtao Li Xingchen Wang Xuezhen Zhang 《Earthquake Science》 2024年第2期93-106,共14页
Lithospheric structure beneath the northeastern Qinghai-Xizang Plateau is of vital significance for studying the geodynamic processes of crustal thickening and expansion of the Qinghai-Xizang Plateau. We conducted a j... Lithospheric structure beneath the northeastern Qinghai-Xizang Plateau is of vital significance for studying the geodynamic processes of crustal thickening and expansion of the Qinghai-Xizang Plateau. We conducted a joint inversion of receiver functions and surface wave dispersions with P-wave velocity constraints using data from the Chin Array Ⅱ temporary stations deployed across the Qinghai-Xizang Plateau. Prior to joint inversion, we applied the H-κ-c method(Li JT et al., 2019) to the receiver function data in order to correct for the back-azimuthal variations in the arrival times of Ps phases and crustal multiples caused by crustal anisotropy and dipping interfaces. High-resolution images of vS, crustal thickness, and vP/vSstructures in the Qinghai-Xizang Plateau were simultaneously derived from the joint inversion. The seismic images reveal that crustal thickness decreases outward from the Qinghai-Xizang Plateau. The stable interiors of the Ordos and Alxa blocks exhibited higher velocities and lower crustal vP/vSratios. While, lower velocities and higher vP/vSratios were observed beneath the Qilian Orogen and Songpan-Ganzi terrane(SPGZ), which are geologically active and mechanically weak, especially in the mid-lower crust.Delamination or thermal erosion of the lithosphere triggered by hot asthenospheric flow contributes to the observed uppermost mantle low-velocity zones(LVZs) in the SPGZ. The crustal thickness, vS, and vP/vSratios suggest that whole lithospheric shortening is a plausible mechanism for crustal thickening in the Qinghai-Xizang Plateau, supporting the idea of coupled lithospheric-scale deformation in this region. 展开更多
关键词 joint inversion receiver functions surface waves crustal thickness vP/vS ratio NE Qinghai-Xizang Plateau
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Surface and Content Validity of the Mentoring Function Scale for Novice Nurses
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作者 Aimi Furukawa Yasuko Hosoda 《Open Journal of Nursing》 2024年第8期401-411,共11页
This study aimed to examine the surface and content validity of the Mentoring Function Scale for Novice Nurses, used to assess the mentoring of entry-level nurses, and to refine the scale items. In Study 1, six nurse ... This study aimed to examine the surface and content validity of the Mentoring Function Scale for Novice Nurses, used to assess the mentoring of entry-level nurses, and to refine the scale items. In Study 1, six nurse education researchers, selected using convenience sampling, with five or more years of nursing experience and experience teaching novice nurses, were invited to an expert meeting in July 2015. A group interview was conducted that lasted approximately 120 minutes. Study 2 examined the content validity index. Between September and November 2015, we distributed a self-administered questionnaire survey to 11 participants selected by convenience sampling. The participants included five nurse education researchers with a minimum of five years of nursing experience and experience teaching novice nurses, as well as six clinical nurses with a master’s degree or higher. Finally, 81 questionnaire items were retained from the initial 125 items. The 81-item Mentoring Function Scale for Novice Nurses had higher content validity than the original scale. To further increase the scale’s applicability, future studies should assess its reliability, construct validity, and criterion-related validity. 展开更多
关键词 Novice Nurses Mentoring function surface and Content Validity Item-Level Content Validity Index
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A facile strategy for tuning the density of surface-grafted biomolecules for melt extrusion-based additive manufacturing applications 被引量:1
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作者 I.A.O.Beeren G.Dos Santos +8 位作者 P.J.Dijkstra C.Mota J.Bauer H.Ferreira Rui L.Reis N.Neves S.Camarero-Espinosa M.B.Baker L.Moroni 《Bio-Design and Manufacturing》 SCIE EI CAS CSCD 2024年第3期277-291,共15页
Melt extrusion-based additive manufacturing(ME-AM)is a promising technique to fabricate porous scaffolds for tissue engi-neering applications.However,most synthetic semicrystalline polymers do not possess the intrinsi... Melt extrusion-based additive manufacturing(ME-AM)is a promising technique to fabricate porous scaffolds for tissue engi-neering applications.However,most synthetic semicrystalline polymers do not possess the intrinsic biological activity required to control cell fate.Grafting of biomolecules on polymeric surfaces of AM scaffolds enhances the bioactivity of a construct;however,there are limited strategies available to control the surface density.Here,we report a strategy to tune the surface density of bioactive groups by blending a low molecular weight poly(ε-caprolactone)5k(PCL5k)containing orthogonally reactive azide groups with an unfunctionalized high molecular weight PCL75k at different ratios.Stable porous three-dimensional(3D)scaf-folds were then fabricated using a high weight percentage(75 wt.%)of the low molecular weight PCL 5k.As a proof-of-concept test,we prepared films of three different mass ratios of low and high molecular weight polymers with a thermopress and reacted with an alkynated fluorescent model compound on the surface,yielding a density of 201-561 pmol/cm^(2).Subsequently,a bone morphogenetic protein 2(BMP-2)-derived peptide was grafted onto the films comprising different blend compositions,and the effect of peptide surface density on the osteogenic differentiation of human mesenchymal stromal cells(hMSCs)was assessed.After two weeks of culturing in a basic medium,cells expressed higher levels of BMP receptor II(BMPRII)on films with the conjugated peptide.In addition,we found that alkaline phosphatase activity was only significantly enhanced on films contain-ing the highest peptide density(i.e.,561 pmol/cm^(2)),indicating the importance of the surface density.Taken together,these results emphasize that the density of surface peptides on cell differentiation must be considered at the cell-material interface.Moreover,we have presented a viable strategy for ME-AM community that desires to tune the bulk and surface functionality via blending of(modified)polymers.Furthermore,the use of alkyne-azide“click”chemistry enables spatial control over bioconjugation of many tissue-specific moieties,making this approach a versatile strategy for tissue engineering applications. 展开更多
关键词 Additive manufacturing BLENDING surface functionalization surface density Click chemistry HUMAN
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Path-Following Control With Obstacle Avoidance of Autonomous Surface Vehicles Subject to Actuator Faults 被引量:1
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作者 Li-Ying Hao Gege Dong +1 位作者 Tieshan Li Zhouhua Peng 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2024年第4期956-964,共9页
This paper investigates the path-following control problem with obstacle avoidance of autonomous surface vehicles in the presence of actuator faults,uncertainty and external disturbances.Autonomous surface vehicles in... This paper investigates the path-following control problem with obstacle avoidance of autonomous surface vehicles in the presence of actuator faults,uncertainty and external disturbances.Autonomous surface vehicles inevitably suffer from actuator faults in complex sea environments,which may cause existing obstacle avoidance strategies to fail.To reduce the influence of actuator faults,an improved artificial potential function is constructed by introducing the lower bound of actuator efficiency factors.The nonlinear state observer,which only depends on measurable position information of the autonomous surface vehicle,is used to address uncertainties and external disturbances.By using a backstepping technique and adaptive mechanism,a path-following control strategy with obstacle avoidance and fault tolerance is designed which can ensure that the tracking errors converge to a small neighborhood of zero.Compared with existing results,the proposed control strategy has the capability of obstacle avoidance and fault tolerance simultaneously.Finally,the comparison results through simulations are given to verify the effectiveness of the proposed method. 展开更多
关键词 Actuator faults autonomous surface vehicle(ASVs) improved artificial potential function nonlinear state observer obstacle avoidance
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Effect of acidic surface functional groups on Cr(Ⅵ) removal by activated carbon from aqueous solution 被引量:8
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作者 ZHOU Hualei CHEN Yunfa 《Rare Metals》 SCIE EI CAS CSCD 2010年第3期333-338,共6页
The activated carbon with high surface area was prepared by KOH activation.It was further modified by H2SO4 and HNO3 to introduce more surface functional groups.The pore structure of the activated carbons before and a... The activated carbon with high surface area was prepared by KOH activation.It was further modified by H2SO4 and HNO3 to introduce more surface functional groups.The pore structure of the activated carbons before and after modification was analyzed based on the nitrogen adsorption isotherms.The morphology of those activated carbons was characterized using scanning electronic microscopy (SEM).The surface functional groups were determined by Fourier transform infrared spectroscopy (FTIR).The quantity of those groups was measured by the Boehm titration method.Cr(VI) removal by the activated carbons from aqueous solution was investigated at different pH values.The results show that compared with H2SO4,HNO3 destructs the original pore of the activated carbon more seriously and induces more acidic surface functional groups on the activated carbon.The pH value of the solution plays a key role in the Cr(VI) removal.The ability of reducing Cr(VI) to Cr(III) by the activated carbons is relative to the acidic surface functional groups.At higher pH values,the Cr(VI) removal ratio is improved by increasing the acidic surface functional groups of the activated carbons.At lower pH values,however,the acidic surface functional groups almost have no effect on the Cr(VI) removal by the activated carbon from aqueous solution. 展开更多
关键词 activated carbon surface functional groups REMOVAL MODIFICATION chromium(VI)
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A nonlocal strain gradient shell model incorporating surface effects for vibration analysis of functionally graded cylindrical nanoshells 被引量:6
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作者 Lu LU Li ZHU +2 位作者 Xingming GUO Jianzhong ZHAO Guanzhong LIU 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2019年第12期1695-1722,共28页
In this pap er, a novel size-dep endent functionally graded (FG) cylindrical shell model is develop ed based on the nonlocal strain gradient theory in conjunction with the Gurtin-Murdoch surface elasticity theory . Th... In this pap er, a novel size-dep endent functionally graded (FG) cylindrical shell model is develop ed based on the nonlocal strain gradient theory in conjunction with the Gurtin-Murdoch surface elasticity theory . The new model containing a nonlocal parameter, a material length scale parameter, and several surface elastic constants can capture three typical typ es of size e ects simultaneously , which are the nonlocal stress ef- fect, the strain gradient e ect, and the surface energy e ects. With the help of Hamilton’s principle and rst-order shear deformation theory , the non-classical governing equations and related b oundary conditions are derived. By using the prop osed model, the free vibra- tion problem of FG cylindrical nanoshells with material prop erties varying continuously through the thickness according to a p ower-law distribution is analytically solved, and the closed-form solutions for natural frequencies under various b oundary conditions are obtained. After verifying the reliability of the prop osed model and analytical method by comparing the degenerated results with those available in the literature, the in uences of nonlocal parameter, material length scale parameter, p ower-law index, radius-to-thickness ratio, length-to-radius ratio, and surface e ects on the vibration characteristic of func- tionally graded cylindrical nanoshells are examined in detail. 展开更多
关键词 NONLOCAL strain gradient THEORY surface elasticity THEORY rst-order shear deformation THEORY vibration functionally graded (FG) CYLINDRICAL NANOSHELL
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Effect of Graphene Surface Functional Groups on the Mechanical Property of PMMA Microcellular Composite Foams 被引量:3
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作者 LI Meijuan SHEN Qiang 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2019年第3期717-722,共6页
The functional groups on graphene sheets surface affect their dispersion and interfacial adhesion in polymer matrix. We compared the mechanical property of polymethymethacrylate(PMMA) microcellular foams reinforced ... The functional groups on graphene sheets surface affect their dispersion and interfacial adhesion in polymer matrix. We compared the mechanical property of polymethymethacrylate(PMMA) microcellular foams reinforced with graphene oxide(GO) and reduced graphene oxide(RGO) to investigate this influence of functional groups. RGO sheets were fabricated by solvent thermal reduction in DMF medium. UV-Vis, FT-IR and XPS analyses indicate the difference of oxygen-containing groups on GO and RGO sheets surface. The observation of SEM illustrates that the addition of a smaller number of GO or RGO sheets causes a fine cellular structure of PMMA foams with a higher cell density(about 1011 cells/cm3) and smaller cell sizes(about 1-2 μm) owing to their remarkable heterogeneous nucleation effect. Compared to GO reinforced foams, the RGO/PMMA foams own lower cell density and bigger cell size in their microstructure, and their compressive strength is lower even when the reinforcement contents are the same and the foam bulk density is higher. These results indicate that the oxygen-containing groups on GO sheets’ surface are beneficial to adhere CO2 to realize a larger nucleation rate, and their strong interaction with PMMA matrix improves the mechanical property of PMMA foams. 展开更多
关键词 GRAPHENE surface functional GROUPS PMMA MICROCELLULAR COMPOSITE FOAMS mechanical property
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Engineered Functional Surfaces by Laser Microprocessing for Biomedical Applications 被引量:6
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作者 Guoqing Hu Kai Guan +3 位作者 Libin Lu Jiaru Zhang Nie Lu Yingchun Guan 《Engineering》 SCIE EI 2018年第6期822-830,共9页
Metallic biomaterials are increasingly being used in various medical applications due to their high strength,fracture resistance,good electrical conductivity,and biocompatibility.However,their practical applications h... Metallic biomaterials are increasingly being used in various medical applications due to their high strength,fracture resistance,good electrical conductivity,and biocompatibility.However,their practical applications have been largely limited due to poor surface performance.Laser microprocessing is an advanced method of enhancing the surface-related properties of biomaterials.This work demonstrates the capability of laser microprocessing for biomedical metallic materials including magnesium and titanium alloys,with potential applications in cell adhesion and liquid biopsy.We investigate laser-material interaction,microstructural evolution,and surface performance,and analyze cell behavior and the surface-enhanced Raman scattering(SERS)effect.Furthermore,we explore a theoretical study on the laser microprocessing of metallic alloys that shows interesting results with potential applications.The results show that cells exhibit good adhesion behavior at the surface of the laser-treated surface,with a preferential direction based on the textured structure.A significant SERS enhancement of 6×10^3 can be obtained at the laser-textured surface during Raman measurement. 展开更多
关键词 LASER microprocessing functionAL surface METALLIC ALLOY Niocompatibility SERS
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Synthesis of fractal geometry and CAGD models for multi-scale topography modelling of functional surfaces 被引量:3
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作者 王清辉 李静蓉 +2 位作者 陈彦政 潘敏强 汤勇 《Journal of Central South University》 SCIE EI CAS 2011年第5期1493-1501,共9页
In order to support the functional design and simulation and the final fabrication processes for functional surfaces,it is necessary to obtain a multi-scale modelling approach representing both macro geometry and micr... In order to support the functional design and simulation and the final fabrication processes for functional surfaces,it is necessary to obtain a multi-scale modelling approach representing both macro geometry and micro details of the surface in one unified model.Based on the fractal geometry theory,a synthesized model is proposed by mathematically combining Weierstrass-Mandelbrot fractal function in micro space and freeform CAGD model in macro space.Key issues of the synthesis,such as algorithms for fractal interpolation of freeform profiles,and visualization optimization for fractal details,are addressed.A prototype of the integration solution is developed based on the platform of AutoCAD's Object ARX,and a few multi-scale modelling examples are used as case studies.With the consistent mathematic model,multi-scale surface geometries can be represented precisely.Moreover,the visualization result of the functional surfaces shows that the visualization optimization strategies developed are efficient. 展开更多
关键词 surface roughness MICROTOPOGRAPHY fractal geometry functional surface
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Laser surface functionalization to achieve extreme surface wetting conditions and resultant surface functionalities 被引量:3
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作者 WANG Qing-hua WANG Hui-xin 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第10期3217-3247,共31页
Wetting condition of micro/nanostructured surface has received tremendous attention due to the potential applications in commercial,industrial,and military areas.Surfaces with extreme wetting properties,e.g.,superhydr... Wetting condition of micro/nanostructured surface has received tremendous attention due to the potential applications in commercial,industrial,and military areas.Surfaces with extreme wetting properties,e.g.,superhydrophobic or superhydrophilic,are extensively employed due to their superior anti-icing,drag reduction,enhanced boiling heat transfer,self-cleaning,and anti-bacterial properties depending on solid-liquid interfacial interactions.Laser-based techniques have gained popularity in recent years to create micro/nano-structured surface owing to their high flexibility,system precision,and ease for automation.These techniques create laser induced periodic surface structures(LIPSS)or hierarchical structures on substrate material.However,micro/nanostructures alone cannot attain the desired wettability.Subsequent modification of surface chemistry is essentially needed to achieve target extreme wettability.This review paper aims to provide a comprehensive review for both laser texturing techniques and the following chemistry modification methods.Recent research progress and fundamental mechanisms of surface structure generation via different types of lasers and various chemistry modification methods are discussed.The complex combination between the laser texturing and surface chemistry modification methods to decide the final wetting condition is presented.More importantly,surface functionalities of these surfaces with extreme wetting properties are discussed.Lastly,prospects for future research are proposed and discussed. 展开更多
关键词 laser surface modification extreme wettability chemistry modification surface functionality
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Bending of functionally graded nanobeams incorporating surface effects based on Timoshenko beam model 被引量:2
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作者 Lihong Yang Tao Fan +2 位作者 Liping Yang Xiao Han Zongbing Chen 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2017年第3期152-158,共7页
The bending responses of functionally graded (FG) nanobeams with simply supported edges are investigated based on Timoshenko beam theory in this article. The Gurtin-Murdoch surface elasticity theory is adopted to an... The bending responses of functionally graded (FG) nanobeams with simply supported edges are investigated based on Timoshenko beam theory in this article. The Gurtin-Murdoch surface elasticity theory is adopted to analyze the influences of surface stress on bending response of FG nanobeam. The material properties are assumed to vary along the thickness of FG nanobeam in power law. The bending governing equations are derived by using the minimum total potential energy principle and explicit formulas are derived for rotation angle and deflection of nanobeams with surface effects. Illustrative examples are implemented to give the bending deformation of FG nanobeam. The influences of the aspect ratio, gradient index, and surface stress on dimensionless deflection are discussed in detail. 展开更多
关键词 Nanobeam functionally graded materials BENDING surface effect Timoshenko beam theory
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Oxygen adsorption on pyrite (100) surface by density functional theory 被引量:6
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作者 孙伟 胡岳华 +1 位作者 邱冠周 覃文庆 《Journal of Central South University of Technology》 2004年第4期385-390,共6页
Pyrite (FeS2) bulk and (100) surface properties and the oxygen adsorption on the surface were studied by using density functional theory methods. The results show that in the formation of FeS2 (100) surface, the... Pyrite (FeS2) bulk and (100) surface properties and the oxygen adsorption on the surface were studied by using density functional theory methods. The results show that in the formation of FeS2 (100) surface, there exists a process of electron transfer from Fe dangling bond to S dangling bond. In this situation, surface Fe and S atoms have more ionic properties. Both Fe2+ and S2- have high electrochemistry reduction activity, which is the base for oxygen adsorption. From the viewpoint of adsorption energy, the parallel form oxygen adsorption is in preference. The result also shows that the state of oxygen absorbed on FeS2 surface acts as peroxides rather than O2. 展开更多
关键词 density functional theory FeS_2 (100) surface surface relaxation oxygen adsorption sulfide flotation
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Analysis of Cost Functions for Retrieving Sea Surface Salinity 被引量:4
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作者 QI Zhen WEI Enbo 《Journal of Ocean University of China》 SCIE CAS 2012年第2期147-152,共6页
Two kinds of Bayesian-based cost functions (i.e., the unconstrained cost function and parameter-constrained cost function) are investigated for retrieving the sea surface salinity (SSS). In low SSS regions, we have an... Two kinds of Bayesian-based cost functions (i.e., the unconstrained cost function and parameter-constrained cost function) are investigated for retrieving the sea surface salinity (SSS). In low SSS regions, we have analyzed the sensitivity of the two cost functions to geophysical parameters. The results show that the unconstrained cost function is valid for retrieving several parameters (including SSS, wind speed and significant wave height), and the constrained cost function, which largely depends on the accuracy of reference values, may lead to large retrieval biases. Furthermore, as a retrieval parameter, the sea surface temperature (SST) can re-sult in the divergence of other geophysical parameters in an unconstrained cost function due to the strong sensitivity of brightness temperature to SST. By using the unconstrained cost function and the simulated brightness temperature TB with white noises, the retrieval biases of SSS are discussed with the following two procedures. Procedure a): the simulated TB values are first averaged, and then SSS is retrieved. Procedure b): the SSS is directly retrieved from the simulated TB , and then the retrieved SSS values are aver-aged. The results indicate that, for low SSS and SST distributions, the SSS retrieval by procedure a) has less biases compared with that by procedure b), while the two procedures give almost the same retrieval results for high SSS and SST sea regions. 展开更多
关键词 cost function sea surface salinity and temperature brighmess temperature
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Time function of surface subsidence based on Harris model in mined-out area 被引量:7
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作者 Liu Xinrong Wang Junbao +2 位作者 Guo Jianqiang Yuan Hong Li Peng 《International Journal of Mining Science and Technology》 SCIE EI 2013年第2期251-254,共4页
The surface subsidence is a common environmental hazard in mined-out area. Based on careful analysis of the regularity of surface subsidence in mined-out area, we proposed a new time function based on Harris curve mod... The surface subsidence is a common environmental hazard in mined-out area. Based on careful analysis of the regularity of surface subsidence in mined-out area, we proposed a new time function based on Harris curve model in consideration of the shortage of current surface subsidence time functions. By analyzing the characteristics of the new time function, we found that it could meet the dynamic process, the velocity change process and the acceleration change process during surface subsidence. Then its rationality had been verified through project cases. The results show that the proposed time function model can give a good reflection of the regularity of surface subsidence in mined-out area and can accurately predict surface subsidence. And the prediction data of the model are a little greater than measured data on condition of proper measured data quantity, which is safety in the engineering. This model provides a new method for the analysis of surface subsidence in mined-out area and reference for future prediction, and it is valuable to engineering application. 展开更多
关键词 Mined-out area surface subsidence Time function Harris model Prediction
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A Periodic Density Functional Study on Adsorption Properties of Methoxy on Au(111) Surface 被引量:2
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作者 刘书红 陈文凯 +3 位作者 曹梅娟 陆春海 许莹 李俊篯 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2006年第1期53-58,共6页
Adsorption of CH3O at four sites (top, bridge, hcp, fcc) on Au(111) surface has been investigated by density functional theory method at the generalized gradient approximation level. We have performed calculations... Adsorption of CH3O at four sites (top, bridge, hcp, fcc) on Au(111) surface has been investigated by density functional theory method at the generalized gradient approximation level. We have performed calculations on adsorption energies, structures, Mulliken charges and vibrational frequencies of CH3O on Au(111) surface with full-geometry optimization. The predicted results are compared with the available experimental observation. The calculated CH3O adsorption structure and stretching vibrational frequencies agree well with experimental ones, and precise determinations of adsorption sites are carded out. The most favorite adsorption on Au(111) occurs at the bridge site, and O-C axis is tilted to the surface. However, on hollow sites (hcp, fcc) the species is adsorbed in an upright geometry (pseudo-C3v local symmetry). 展开更多
关键词 density functional theory (DFT) Au(111) surface CH3O ADSORPTION
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Adaptive integral dynamic surface control based on fully tuned radial basis function neural network 被引量:2
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作者 Li Zhou Shumin Fei Changsheng Jiang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2010年第6期1072-1078,共7页
An adaptive integral dynamic surface control approach based on fully tuned radial basis function neural network (FTRBFNN) is presented for a general class of strict-feedback nonlinear systems,which may possess a wid... An adaptive integral dynamic surface control approach based on fully tuned radial basis function neural network (FTRBFNN) is presented for a general class of strict-feedback nonlinear systems,which may possess a wide class of uncertainties that are not linearly parameterized and do not have any prior knowledge of the bounding functions.FTRBFNN is employed to approximate the uncertainty online,and a systematic framework for adaptive controller design is given by dynamic surface control. The control algorithm has two outstanding features,namely,the neural network regulates the weights,width and center of Gaussian function simultaneously,which ensures the control system has perfect ability of restraining different unknown uncertainties and the integral term of tracking error introduced in the control law can eliminate the static error of the closed loop system effectively. As a result,high control precision can be achieved.All signals in the closed loop system can be guaranteed bounded by Lyapunov approach.Finally,simulation results demonstrate the validity of the control approach. 展开更多
关键词 adaptive control integral dynamic surface control fully tuned radial basis function neural network.
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Selective removal of heavy metal ions from aqueous solutions with surface functionalized silica nanoparticles by different functional groups 被引量:3
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作者 孔祥峰 杨斌 +4 位作者 熊恒 周阳 薛生国 徐宝强 王世兴 《Journal of Central South University》 SCIE EI CAS 2014年第9期3575-3579,共5页
The industrial silica fume pretreated by nitric acid at 80 °C was re-used in this work. Then, the obtained silica nanoparticles were surface functionalized by silane coupling agents, such as(3-Mercaptopropyl) tri... The industrial silica fume pretreated by nitric acid at 80 °C was re-used in this work. Then, the obtained silica nanoparticles were surface functionalized by silane coupling agents, such as(3-Mercaptopropyl) triethoxysilane(MPTES) and(3-Amincpropyl) trithoxysilane(APTES). Some further modifications were studied by chloroaceetyl choride and 1,8-Diaminoaphalene for amino modified silica. The surface functionalized silica nanoparticles were characterized by Fourier transform infrared(FI-IR) and X-ray photoelectron spectroscopy(XPS). The prepared adsorbent of surface functionalized silica nanoparticles with differential function groups were investigated in the selective adsorption about Pb2+, Cu2+, Hg2+, Cd2+ and Zn2+ions in aqueous solutions. The results show that the(3-Mercaptopropyl) triethoxysilane functionalized silica nanoparticles(SiO2-MPTES) play an important role in the selective adsorption of Cu2+ and Hg2+, the(3-Amincpropyl) trithoxysilane(APTES) functionalized silica nanoparticles(SiO2-APTES) exhibited maximum removal efficiency towards Pb2+ and Hg2+, the 1,8-Diaminoaphalene functionalized silica nanoparticles was excellent for removal of Hg2+ at room temperature, respectively. 展开更多
关键词 industrial silica fume surface functionalization heavy metal ions selective removal
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Degenerations of rational Bézier surface with weights in the form of exponential function 被引量:1
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作者 ZHANG Yue ZHU Chun-gang GUO Qing-jie 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2017年第2期164-182,共19页
Rational Bezier surface is a widely used surface fitting tool in CAD. When all the weights of a rational B@zier surface go to infinity in the form of power function, the limit of surface is the regular control surface... Rational Bezier surface is a widely used surface fitting tool in CAD. When all the weights of a rational B@zier surface go to infinity in the form of power function, the limit of surface is the regular control surface induced by some lifting function, which is called toric degenerations of rational Bezier surfaces. In this paper, we study on the degenerations of the rational Bezier surface with weights in the exponential function and indicate the difference of our result and the work of Garcia-Puente et al. Through the transformation of weights in the form of exponential function and power function, the regular control surface of rational Bezier surface with weights in the exponential function is defined, which is just the limit of the surface. Compared with the power function, the exponential function approaches infinity faster, which leads to surface with the weights in the form of exponential function degenerates faster. 展开更多
关键词 rational Bezier surface WEIGHTS regular control surface toric degenerations exponential function.
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Interaction of Photoactive[Fe(CN)_6]^(4-) with TiO_2 Anatase(101) Surface:A Periodic Density Functional Theory Study 被引量:2
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作者 XU Ying CHEN Wen-Kai CAO Mei-Juan LIU Shu-Hong LI Jun-Qian 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2007年第3期361-366,共6页
The plane-wave pseudopotential function method, based on density-functional theory, has been used to calculate the adsorption, electronic band structures, orbitals and optical absorption spectrum of [Fe(CN)6]^4- on ... The plane-wave pseudopotential function method, based on density-functional theory, has been used to calculate the adsorption, electronic band structures, orbitals and optical absorption spectrum of [Fe(CN)6]^4- on TiOz anatase(101) surface. Our calculations reveal that the surface-modified anatase system has large adsorption energy and a much narrower band gap. [Fe(CN)6]^4- adsorption on the (101) surface could lead to a large red shift of the anatase optical absorption threshold, which extends into a visible region significantly. The calculated results are in agreement with the experiment and other theoretical studies reasonably. It is very important for the understanding and further development ofphotovoltaic materials that are active under visible light. 展开更多
关键词 density functional theory (DFT) [Fe(CN)6]^4- anatase(101) surface adsorption absorption
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