INTEGRATION SHAPE AND SIZING OPTIMIZATION OF COMPOSITE WING STRUCTURE BASED ON RESPONSE SURFACE METHOD

An effective optimization method for the shape/sizing design of composite wing structures is presented with satisfying weight-cutting results. After decoupling, a kind of two-layer cycled optimization strategy suitable for these integrated shape/sizing optimization is obtained. The uniform design method is used to provide sample points, and approximation models for shape design variables. And the results of sizing optimization are construct- ed with the quadratic response surface method （QRSM）. The complex method based on QRSM is used to opti- mize the shape design variables and the criteria method is adopted to optimize the sizing design variables. Compared with the conventional method, the proposed algorithm is more effective and feasible for solving complex composite optimization problems and has good efficiency in weight cutting.

Composite Structural Optimization by Genetic Algorithm and Neural Network Response Surface Modeling

Neural-Network Response Surfaces （NNRS） is applied to replace the actual expensive finite element analysis during the composite structural optimization process. The Orthotropic Experiment Method （OEM） is used to select the most appropriate design samples for network training. The trained response surfaces can either be objective function or constraint conditions. Together with other conven- tional constraints, an optimization model is then set up and can be solved by Genetic Algorithm （GA）. This allows the separation between design analysis modeling and optimization searching. Through an example of a hat-stiffened composite plate design, the weight response surface is constructed to be objective function, and strength and buckling response surfaces as constraints; and all of them are trained through NASTRAN finite element analysis. The results of optimization study illustrate that the cycles of structural analysis ean be remarkably reduced or even eliminated during the optimization, thus greatly raising the efficiency of optimization process. It also observed that NNRS approximation can achieve equal or even better accuracy than conventional functional response surfaces.

Application of Monodisperse Thermo-Responsive Composite Microgels with Core-Shell Structure Based on Au@Ag Bimetallic Nanorod as Core in Surface Enhanced Raman Spectroscopy Substrate

The monodisperse Au@Ag bimetallic nanorod is encapsulated by crosslinked poly( N-isopropylacrylamide)( PNIPAM) to produce thermo-responsive composite microgel with well-defined core-shell structure( Au@ Ag NR@ PNIPAM microgel)by seed-precipitation polymerization method using butenoic acid modified Au @ Ag NRs as seeds. When the temperature of the aqueous medium increases from 20℃ to 50℃,the localized surface plasmon resonance( LSPR) band of the entrapped Au @ Ag NR is pronouncedly red-shifted because of the decreased spatial distances between them as a result of shrinkage of the microgels,leading to their plasmonic coupling. The temperature tunable plasmonic coupling is demonstrated by temperature dependence of the surface enhanced Raman spectroscopy( SERS) signal of 1-naphthol in aqueous solution. Different from static plasmonic coupling modes from nanostructured assembly or array system of noble metals,the proposed plasmonic coupling can be dynamically controlled by environmental temperature. Therefore, the thermo responsive hybrid microgels have potential applications in mobile LSPR or SERS microsensors for living tissues or cells.

Investigation on Surface Plasmon Polaritons and Localized Surface Plasmon Production Mechanism in Micro-Nano Structures

The simulation mechanism of surface plasmon polaritons(SPPs)and localized surface plasmon(LSP)in different structures was studied,including the Au reflection grating(Au grating),Au substrate with dielectric ribbons grating(Au substrate grating),and pure electric conductor(PEC)substrate with Au ribbons grating(Au ribbons grating).And the characteristics of the Smith-Purcell radiation in these structures were presented.Simulation results show that SPPs are excited on the bottom surface of Au substrate grating grooves and LSP is stimulated on the upper surface both of Au ribbons grating grooves and Au grating grooves.Owing to the irreconcilable contradiction between optimizing the grating diffraction radiation efficiency and optimizing the SPPs excitation efficiency in the Au substrate grating,only 40-times enhancement of the radiation intensity was obtained by excited SPPs.However,the LSP enhanced structure overcomes the above problem and gains much better radiation enhancement ability,with about 200-times enhancement obtained in the Au ribbons grating and more than 500-times enhancement obtained in the Au grating.The results presented here provide a way of developing miniature,integratable,tunable,high-power-density radiation sources from visible light to ultraviolet rays at room temperature.

Three-Dimensional Cu-Ni Composite Superamphiphobic Surface via Electrodeposition and Fluorosilane Modification

A superamphiphobic(SAP)surface was fabricated by electrodepositing Cu-Ni micro-nano particles on aluminum substrate and modifying via 1 H,1 H,2 H,2 Hperfluorodecyltrimethoxysilane.Scanning electron microscopy,X-ray diffraction,energydispersive X-ray spectroscopy,and Fourier-transform infrared spectroscopy were employed to investigate the morphology and chemical composition.The results showed that the SAP surface had three-dimensional micro-nano structures and exhibited a maximum water contact angle of 160.0°,oil contact angle of 151.6°,a minimum water slide angle of 0°and oil slide angle of 9°.The mechanical strength and chemical stability of the SAP surface were tested further.The experimental results showed that the SAP surface presented excellent resistance to wear,prominent acid-resistance and alkali-resistance,self-cleaning and anti-fouling properties.

Structural design and mechanical performance of composite vascular grafts

This study reviews the state of the art in structural design and the corresponding mechanical behaviours of composite vascular grafts. We critically analyse surface and matrix designs composed of layered, embedded, and hybrid structures along the radial and longitudinal directions;materials and manufacturing techniques, such as tissue engineering and the use of textiles or their combinations;and the corresponding mechanical behaviours of composite vascular grafts in terms of their physical–mechanical properties, especially their stress–strain relationships and elastic recovery. The role of computational studies is discussed with respect to optimizing the geometrics designs and the corresponding mechanical behaviours to satisfy specialized applications, such as those for the aorta and its subparts. Natural and synthetic endothelial materials yield improvements in the mechanical and biological compliance of composite graft surfaces with host arteries. Moreover,the diameter, wall thickness, stiffness, compliance, tensile strength, elasticity, and burst strength of the graft matrix are determined depending on the application and the patient. For composite vascular grafts, hybrid architectures are recommended featuring multiple layers, dimensions, and materials to achieve the desired optimal flexibility and function for complying with user-specific requirements. Rapidly emerging artificial intelligence and big data techniques for diagnostics and the threedimensional(3D) manufacturing of vascular grafts will likely yield highly compliant, subject-specific, long-lasting, and economical vascular grafts in the near-future.

Support surface pore structures matter: Effects of support surface pore structures on the TFC gas separation membrane performance over a wide pressure range

In this work, the effects of support surface pore structures(including surface pore size, surface pore density and surface porosity) on the performance of thin film composite(TFC) gas separation membrane over a wide pressure range(from 0.3 to 2.0 MPa) were studied. To fulfill it, the polysulfone(PSf) supports with different surface pore structures were prepared. Two kinds of wide-accepted polymeric membrane materials, i.e., polyvinylamine(PVAm) and Pebax 1657 copolymer, were used as skin layer materials. We pointed out for the first time that the support surface average pore size and pore density could affect the chain mobility of polymer of skin layer at the support surface pore entrance, then, can affect the TFC membrane performance. Besides, we also discussed the effects of support on the TFC membrane performance when the feed pressure changes for the first time. This work can provide guidance for choosing a suitable support for TFC gas separation membrane.

Compositional, Structural, Surface Characterizations of Natural Magnetite from Air Massif (Niger) in Relation to Its Catalytic Activity

Ferrimagnetic materials such as natural magnetite are used for practical applications because of their electronic, magnetic and catalytic properties in the degradation of organic compounds. In order to determine its physicochemical properties in relation to its catalytic activity, the natural magnetite of Ofoud Mount (Niger) is characterized by X-ray florescence (XRF), X-ray diffraction (DRX), specific surface area (BET) and Fourier transformed infrared (FTIR). The result shows an iron content of 97.09% and a specific surface area of 69.742 m2/g. The crystal structure of magnetite is cubic with lattice parameters α = β = γ = 90°, a (Å) = b (Å) = c (Å) = 8.3740. The results of this study suggest that the natural magnetite of Ofoud Mount can be used as iron source in various fields of science despite the presence of a few impurities that can improve its catalytic activity.

Change in the Pore Structure of Carbon-Carbon Composites during Successive Stages of High-Pressure Impregnation and Heat Treatment

Pore structure of C/C （Carbon-Carbon） composite after several stages of pitch impregnation under the high pressure and heat treatment was investigated by means of low temperature nitrogen adsorption and the standard contact porosimetry. Total pore volume, pore size distribution and specific surface area were calculated for samples of composite after several successive stages of treatment. The radius of pores presented in the material changes from 1 nm to 90 tam. Total pore volume and specific surface area both decrease after successive stages of pitch impregnation under the pressure, whereas heat treatment up to 1,750 ℃ and 2,000 ℃ leads to creation of some porous space and pore volume expansion. The bulk porosity of C/C composite comes down from 33.7% to 13.7% after the serial stages of treatment and the specific surface area is reduced by half compared to the initial material.

Recent development of LiNi_xCo_yMn_zO_2:Impact of micro/nano structures for imparting improvements in lithium batteries

The recent advancement in the design,synthesis,and fabrication of micro/nano structured LiNixCoyMnzO2 with one-,two-,and three-dimensional morphologies was reviewed.The major goal is to highlight LiNixCoyMnzO2 materials,which have been utilized in lithium ion batteries with enhanced energy and power density,high energy efficiency,superior rate capability and excellent cycling stability resulting from the doping,surface coating,nanocomposites and nano-architecturing.

Bioinspired Functional Surfaces for Medical Devices

Medical devices are a major component of precision medicine and play a key role in medical treatment,particularly with the rapid development of minimally invasive surgery and wearable devices.Their tissue contact properties strongly affect device performance and patient health(e.g.,heat coagulation and slipperiness on surgical graspers).However,the design and optimization of these device surfaces are still indistinct and have no supporting principles.Under such conditions,natural surfaces with various unique functions can provide solutions.This review summarizes the current progress in natural functional surfaces for medical devices,including ultra-slipperiness and strong wet attachment.The underlying mechanisms of these surfaces are attributed to their coupling effects and featured micronano structures.Depending on various medical requirements,adaptable designs and fabrication methods have been developed.Additionally,various medical device surfaces have been validated to achieve enhanced contact properties.Based on these studies,a more promising future for medical devices can be achieved for enhanced precision medicine and human health.

Generalized model for laser-induced surface structure in metallic glass

The details of the special three-dimensional micro-nano scale ripples with a period of hundreds of microns on the surfaces of a Zr-based and a La-based metallic glass irradiated separately by single laser pulse are investigated.We use the small-amplitude capillary wave theory to unveil the ripple formation mechanism through considering each of the molten metallic glasses as an incompressible viscous fluid.A generalized model is presented to describe the special morphology,which fits the experimental result well.It is also revealed that the viscosity brings about the biggest effect on the monotone decreasing nature of the amplitude and the wavelength of the surface ripples.The greater the viscosity is,the shorter the amplitude and the wavelength are.

Physical Characterization and Elaboration Discussion of a Clay-PEG 6000 Composite with Natural Clay Matrix

In this paper, we compare different nanoclay-PEG composites and the influence of the input parameters especially the percentage of PEG and the clay size. Because of the facility of material elaboration, dried state with grinding, we adopted a complete experiments plan to obtain a maximum of robustness of the responses. For each sample, we made an XRD analysis to see if we obtain the intercalation of the PEG 6000 (Polyethylene Glycol 6000) within the clay sheets. The characterization adopted consists on the measurement of the shrinking of some cylinders we made, the liquidity and plasticity limits according to the Casagrande protocol used in geotechnical clays characterizations. We utilize also the methylen blue protocol to estimate the variation of the specific surface of ionic exchange of the clay sheets according to the PEG 6000 percentage and the clay sizes. SEM microscopy permits to visualize some of the phases detected by the XRD analysis. The TEM microscopy permits also to see the amorphous phases created by the grinding protocol which affects significantly the specific surface and the shrinking of the new materials. For each section, we made some conclusions with interpretation in order to integrate these results in civil engineering, classical/artisanal material construction and geotechnical fields.

Surface Micro-Nano Structures on GaN Thin Films Induced by 355 nm Nanosecond Laser Irradiation

Gallium nitride(GaN)has widespread applications in the semiconductor industry because of its desirable optoelectronic properties.The fabrication of surface structures on GaN thin films can effectively modify their optical and electrical properties,providing additional degrees of freedom for controlling GaN-based devices.Compared with lithography-based techniques,laser processing is maskless and much more efficient.This paper shows how surface micronano structures can be produced on GaN thin films using 355 nm nanosecond laser irradiation.The effects of the laser pulse energy,number of pulses,and polarization direction were studied.It was found that distinct micro-nano structures were formed under different irradiation conditions,and their geometries and elemental compositions were analyzed.The results indicate that different types of surface micro-nano structures can be produced on GaN thin films in a controllable manner using 355 nm nanosecond laser irradiation.The results of our study provide valuable guidance for the surface modification of GaN-based optoelectronic devices.

纤维缠绕塑料内胆表面处理装置的设计与分析

为提高目前塑料内胆的表面处理质量以及处理时间,节约时间和人工成本,本文针对纤维缠绕塑料内胆的表面处理设计了一套自动化的处理装置。它主要可以实现塑料内胆的自动夹持夹紧定位以及塑料内胆表面处理等功能。文中主要介绍了所设计的夹持传动装置以及等离子表面处理装置等相关结构,并在SolidWorks软件中对此套装置进行了总体设计与装配,在Workbench中对部分零部件进行了强度校核,分析Workbench中的相关结果。结果显示,该装置达到了相关力学要求且能够平稳传动,满足设计要求。

基于粘附功计算的不同微形貌表面抗冰差异

超疏水表面的防水性与表面的微观结构直接相关,不同微观形貌将呈现不同的疏水性能,从而亦产生不同的防覆冰性。代表性的选择动植物叶片、翼片、金属与非金属等工程材料固体表面做结冰和覆冰粘附强度测试,结果表明表面材料、微观结构不同,疏水、覆冰粘附性能不一样。设计了几种不同表面微形貌模型仿真自然和人工疏水表面微结构,用高粗糙度维持复合润湿状态,以具有矩形微形貌的表面为例建立覆冰粘附功与表面固体份数的解析关系,并推及其它模型。据粘附功、固体份数和粗糙度计算,发现不同微形貌表面覆冰粘附功的差异,固体份数对粘附功的决定作用以及粗糙度对复合润湿态的维持。理论上提出了选择适合的微观形貌用于防冰的定性标准:高粗糙度,低固体份数,低粘附功。按粘附功从小到大顺序确定适合于防冰、除冰微形貌;从固体份数和粗糙度的大小关系予以证实。

基于相关性分析和响应面法的复合旋流器结构参数优化

为了提高旋流器优化参数的准确性,得到其在结构优化中的最优解,以一种新型复合旋流器为研究对象,基于相关性的单因素分析寻优法,以相关性分析的结果来指导优化范围的选取,提高其结构参数优化范围的准确性。结合响应面优化方法,以分离效率为优化目标,确定旋流器的最优结构参数,建立了分离效率和结构参数之间的回归模型。结果表明:不同的结构参数和各性能指标之间的显著关系并不相同,根据相关性分析的结果确定各结构的优化范围为:上锥角为0°~4°,下锥角为8°~12°,底流口直径为12~16 mm;响应面优化得到旋流器最优结构为:上锥角为2.565°,下锥角为11.719°,底流口直径为12.889 mm,在本组参数下旋流器固体分离效率达到了99.945%,气体分离效率达到了93.807%。为旋流器的结构优化提供了一种新方法。

激光电沉积复合制备定域微纳结构及其超疏水性能研究

目的实现金属超疏水表面特定微纳结构的定域制备。方法利用激光电沉积复合工艺(LECP)制备出由Cu微米锥和Ni纳米锥所组成的定域微纳结构。首先,依次使用800目和2000目砂纸机械抛光纯铜表面,皮秒激光刻蚀纯铜表面,获得周期性的微米锥结构,并电解去除熔融产物。在电沉积加工过程中引入激光辐照,进而控制Ni纳米锥结构的定域生长。分别将机械抛光、激光刻蚀、激光刻蚀后电沉积(常温、60℃)、LECP所制备的微纳结构表面进行化学改性处理,对所得样品的表面形貌、化学成分、疏水性能、自清洁、延迟结冰和耐腐蚀性能进行对比分析。结果与激光刻蚀后电沉积相比,LECP能够定域制备Ni纳米锥结构。LECP定域制备的微纳结构表面经化学改性后实现了超疏水,其接触角为163°±2°,滚动角为1°±0.5°。与未加工微纳结构的表面相比,LECP制备样品表面水滴结冰时间延长近5倍,腐蚀电流密度减小了2个数量级。结论本研究通过LECP实现了表面微纳结构的定域制备,为超疏水表面的应用提供了一种新的技术手段。

Magneto-electric integrated design strategy of NiCo@C composites for synergistic absorption and conversion in mid-high frequency microwaves

Achieving synergistic absorption of electromagnetic waves(EMWs)in the mid-high frequency and absorption band conversion is an urgent problem.However,the present solution is usually a straightforward mixture of magnetic component-carbon component.Hereby,we optimize the magnetic properties and electrical relaxation response from a chemical synthesis perspective.Through integrated design,the contents of carbon components and multi-dimensional morphology are controlled by retaining strong magnetic properties.The morphology design and the construction of heterogeneous interfaces will boost the intense response of charge in the surrounding to enhance the polarization effect.The multi-dimensional structure and electromagnetic(EM)properties of the sample after optimized engineering have an extremely powerful absorption conversion effect on EMW energy.NiCo@C particles ultimately achieve synergistic absorption effects at low thickness(d<3.5 mm)at middle frequencies(6–10 GHz)and high frequencies(10.5–18 GHz).Our work establishes a correlation mechanism between the physical and chemical properties of materials and EM parameters.It also provides insight into the synergistic absorption of EMWs in the mid-high frequency and absorption band conversion strategies.

Formation of Laser-Induced Periodic Surface Structures on Reaction-Bonded Silicon Carbide by Femtosecond Pulsed Laser Irradiation

Reaction-bonded silicon carbide(RB-SiC)is an excellent engineering material with high hardness,stiffness,and resistance to chemical wear.However,its widespread use is hindered due to the properties mentioned above,making it difficult to machine functional surface structures through mechanical and chemical methods.This study investigated the fundamental characteristics of laser-induced periodic surface structures(LIPSSs)on RB-SiC via femtosecond pulsed laser irradiation at a wavelength of 1028 nm.Low-spatial-frequency LIPSS(LSFL)and high-spatial-frequency LIPSS(HSFL)formed on the surface along directions perpendicular to the laser polarization.SiC grains surrounded by a large amount of Si show a reduced threshold for LIPSS formation.By varying laser fluence and scanning speed,HSFL-LSFL hybrid structures were generated on the SiC grains.Transmission electron microscopy observations and Raman spectroscopy were carried out to understand the formation mechanism of the hybrid LIPSS.A possible mechanism based on the generation of multiple surface electromagnetic waves due to the nonlinear response of SiC was proposed to explain the hybrid structure formation.Furthermore,the direction of laser scanning with respect to laser polarization affects the uniformity of the generated LIPSS.