包钢厚料层烧结实践

通过采取强化混合料制粒 ,实施厚料层烧结 ,提高混合料温度 ,采取偏析布料等 ,包钢在全精矿条件下实现了 5 5 0mm厚料层烧结。烧结工艺技术指标及烧结矿质量明显提高 ,取得了良好的经济效益。

磨料有序排布金刚石锯片的加工性能试验研究

设计并制作了3组新型磨料有序排布烧结金刚石锯片和1组无序锯片,进行了635#花岗岩对比切割试验。对有序排布锯片的胎体磨损进行了分析,研究了金刚石浓度、锯片外径等因素对有序排布锯片锋利度与寿命的影响。研究发现:有序排布锯片边料层与中料层之间有个最佳金刚石浓度差,使得有序排布锯片具有最优的锋利度与寿命;有序锯片锋利度好于无序锯片,有序锯片切割性能较无序锯片稳定,有序排布锯片还可以减少金刚石浓度、节约金刚石用量、降低10%以上的金刚石材料成本。

INTERLAMINAR FRACTURE TOUGHNESS OF MULTI-DIRECTIONAL LAMINATES

Based on the conventional compliance and area methods, a high precision method named the angle method is presented in this work. The interlaminar fracture toughness is determined by measurement of the load and the bending angle at the loading point without measurement of the crack length, and the improvement of the conventional compliance method is made, which is more precise and can be used to general DCB specimen with unequal flexural stiffness of the cantilevers. The interlaminar fracture toughness in 0/ θ(θ =0°,30°,60°,90°) interfaces of two epoxy composites, one being the carbon fibre reinforced brittle matrix T300/4211, the other the carbon fibre reinforced tough matrix T300/3261, is measured by both compliance and angle methods, and the relationship between fracture toughness and the ply angle θ is obtained. It is found that the interlaminar fracture toughness is correlated with the type of matrix and the ply angles near the crack front.

Preliminary Evaluation of a Model for Stratiform Cloud Microphysical Structure by Observation and Simulation

The microphysical "three-layer" model for stratiform clouds over a midlatitude location in Northwest China is investigated by combining in situ airborne Particle Measuring Systems, Inc. (PMS), radar measurements, and the NCAR/Penn State Mesoscale Model Version 5 (MM5) simulation with a two-moment microphysics scheme. The coexistence of measured supercooled liquid water and small ice particles produces snow particles below the cloud top in the second layer. Peak number concentration and mean diameter of cloud water and raindrop appear in the third warm layer. A thin dry layer just below the melting layer is also observed. The predicted precipitation is tested by equitable threat score. The melting layer is clearly defined in the radar image and model radar reflectivity output is agreement with the observations. The model results provide features of the microphysical structure for every layer of "three-layer" model at Yan'an station. For both observation and model simulation, the "three-layer" model explains the stratiform precipitation formation completely and comprehensively.

Application of Coherence Inversion Method to Shallow Reflection

Because of the disturbance of some regular waves, the deformity of reflective wave occurs, making the coherence inversion method unreliable. By using the event time from multi fold reflective stack the range of model parameters obtained by coherence inversion is limited in coherence inversion. Then by adjusting the initial values of the model parameters to make the waveform from the coherence inversion method be consistent with that from the original reflective gathers, the result of the inversion becomes more reliable. The application of this method in processing the reflective gathers in Songzikou by the Jingjiang River of Hubei demonstrates the efficiency of the method.

Direct Assessment of Interlaminar Stresses in Composite Multilayered Plates Using a Layer-Wise Mixed Finite Element Model

An accurate determination of intedaminar transversal stresses in composite multilayered plates, especially near free-edge, is of great importance in the study of inter-ply damage modes, mainly in the initiation and growth of delamination. In this paper, interlaminar stresses are determined by layer-wise mixed finite element model. Each layer is analyzed as an isolated one where the displacement continuity is ensured by means of Lagrange multipliers （which represent the statics variables）. This procedure allows the authors to work with any single plate model, obtaining the interlaminar stresses directly without loss of precision. The FSDT （first shear deformation theory） with transverse normal strain effects included is assumed in each layer, but Lagrange polynomials are used to describe the kinematic instead of Taylor＇s polynomial functions of the thickness coordinates, as is common. This expansion allows the authors to pose the interlaminar displacements compatibility simpler than the second one. The in-plane domain of the plate is discretized by four-node quadrilateral elements, both to the field of displacement and to the Lagrange multipliers. The mixed interpolation of tensorial components technique is applied to avoid the shear-locking in the finite element model. Several examples were carried out and the results have been satisfactorily compared with those available in the literature.

Delamination analysis of woven fabrication laminates using cohesive zone model

A new test method was proposed to evaluate the cohesive strength of composite laminates. Cohesive strength and the critical strain energy for Mode-II interlamiar fracture of E-glass/epoxy woven fabrication were determined from the single lap joint(SLJ) and end notch flexure(ENF) test, respectively. In order to verify their adequacy, a cohesive zone model simulation based on interface finite elements was performed. A closed form solution for determination of the penalty stiffness parameter was proposed. Modified form of Park-Paulino-Roesler traction-separation law was provided and conducted altogether with trapezoidal and bilinear mixed-mode damage models to simulate damage using Abaqus cohesive elements. It was observed that accurate damage prediction and numerical convergence were obtained using the proposed penalty stiffness. Comparison between three damage models reveals that good simulation of fracture process zone and delamination prediction were obtained using the modified PPR model as damage model. Cohesive zone length as a material property was determined. To ensure the sufficient dissipation of energy, it was recommended that at least 4 elements should span cohesive zone length.

Mechanical properties of AISI 1045 ceramic coated materials by nano indentation and crack opening displacement method

Abstract： An effective approach was conducted for estimating fracture toughness using the crack opening displacement （COD） method for plasma enhanced chemical vapor deposition （PECVD） coating materials. For this evaluation, an elastoplastic analysis was used to estimate critical COD values for single edge notched bending （SENB） specimens. The relationship between fracture toughness （Kic） and critical COD for SENB specimens was obtained. Microstructure of the interface between AleO3-TiO2 composite ceramic coatings and AISI 1045 steel substrates was studied by using scanning electron microscope （SEM）. Chemical compositions were clarified by energy-dispersive X-ray spectroscopy （EDS）. The results show that the interface between of Al203-TiO2 and substrate has mechanical combining. The nanohardness of the coatings can reach 1 200 GPa examined by nanoindentation. The Klc was calculated according to this relationship from critical COD. The bending process produces a significant relationship of COD independent of the axial force applied. Fractographic analysis was conducted to determine the crack length. From the physical analysis of nanoindentation curves, the elastic modulus of 1045/AI2O3-TiO2 is 180 GPa for the 50 μm film. The highest value of fracture toughness for 1045/A1203-TiO2-250 μm is 348 MPa·mv2.

Adsorption of Cationic Laser Dye onto Polymer/Surfactant Complex Film

Fabrication of complex molecular films of organic materials is one of the most important issues in modern nanoscience and nanotechnology. Soft materials with flexible properties have been given much attention and can be obtained through bottom up processing from functional molecules, where self-assembly based on supramolecular chemistry and designed assembly have become crucial processes and technologies. In this work, we report the successful incorporation of cationic laser dye rhodamine 6G abbreviated as R6G into the pre-assembled polyelectrolyte/surfactant complex film onto quartz substrate by electrostatic adsorption technique. Poly（allylamine hydrochloride） （PAH） was used as polycation and sodium dodecyl sulphate （SDS） was used as anionic surfactant. UV-Vis absorption spectroscopic characterization reveals the formation of only H-type aggregates of R6G in their aqueous solution and both H- and J-type aggregates in PAH/SDS/R6G complex layer-bylayber films as well as the adsorption kinetics of R6G onto the complex films. The ratio of the absorbance intensity of two aggregated bands in PAH/SDS/R6G complex fihns is merely independent of the concentration range of the SDS solution used to fabricate PAH/SDS complex self-assembled films. Atomic force microscopy reveals the formation of R6G aggregates in PAH/SDS/R6G complex films.

Characterisation, Analysis and Design of Hydrated Cement Treated Crushed Rock Base as a Road Base Material in Western Australia

Hydrated Cement Treated Crushed Rock Base （HCTCRB） is widely used as a base course in Western Australian pavements. HCTCRB has been designed and used as a basis for empirical approaches and in empirical practices. These methods are not all-encompassing enough to adequately explain the behaviour of HCTCRB in the field. Recent developments in mechanistic approaches have proven more reliable in the design and analysis of pavement, making it possible to more effectively document the characteristics of HCTCRB. The aim of this study was to carry out laboratory testing to assess the mechanical characteristics of HCTCRB. Conventional triaxial tests and repeated load triaxial tests （RLT tests） were performed. Factors affecting the performance of HCTCRB, namely hydration periods and the amount of added water were also investigated. It was found that the shear strength parameters of HCTCRB were 177 kPa for cohesion （c） and 42~ for the internal friction angle （~）. The hydration period, and the water added in this investigation affected the performance of HCTCRB. However, the related trends associated with such factors could not be assessed. All HCTCRB samples showed stress-dependency behaviour. Based on the stress stages of this experiment, the resilient modulus values of HCTCRB ranged from 300 MPa to 1100 MPa. CIRCLY, a computer program based on the multi-layer elastic theory was used in the mechanistic approach to pavement design and analysis, to determine the performance of a typical pavement model using HCTCRB as a base course layer. The mechanistic pavement design parameters for HCTCRB as a base course material were then introduced. The analysis suggests that the suitable depth for HCTCRB as a base layer for WA roads is at least 185 mm for the design equivalent standard axle （ESA） of 10 million.

Comparison in characterization of composite and sol-gel coating on AZ31 magnesium alloy

An Al2O3 protective coating on magnesium alloy AZ31 was prepared by a repeated direct sol-gel process annealing at 300℃and a composite coating was also deposited using Al2O3 particles dispersed sol followed by phosphating treatment and annealing at 300℃.The morphologies,structures and critical adhesive loads as well as corrosion properties of the coatings were comparatively investigated by scanning electron microscopy(SEM),X-ray diffractometry(XRD),nanoscratch test and electrochemical measurement.The results show that the composite coating has a more uniform,crack-free layer and improved adhesion to the substrate as compared with that of the repeated direct sol-gel coating owing to its lower heat strain.The main phases in both coatings consist ofγ-Al2O3 andδ-Al2O3 derived from annealed alumina sol,and the composite coating has an anticorrosion performance which is superior to that of the repeated direct sol-gel coating.

Liquid-phase epitaxy of metal organic framework thin films

Metal-organic framework(MOF) thin films are multilayer materials ranging from nanometers to micrometers in thickness,physically or chemically adhesive to a(functionalized) substrate and,in an ideal case,exhibiting low roughness and high homogeneity.Various innovative approaches have been developed for MOF thin film fabrication.Among these advanced materials,surface-attached metal-organic frameworks(SURMOFs) are an important class of MOF films.SURMOFs,fabricated in a step-by-step liquid phase epitaxial(LPE) fashion by alternating deposition of metal and organic linker precursors on a functionalized substrate,for example,thiolate-based self-assembled monolayers(SAMs),have already exhibited their utility in both research and potential applications.SURMOFs combine surface science and the chemistry of MOFs,possessing the following unique advantages that cannot be accessed through other methods:(i) precisely controlling thickness,roughness and homogeneity as well as growth orientation,(ii) studying of MOF growth mechanism,(iii) modifying/tailoring MOFs' structures during the SURMOF growth and thus creating customizable properties,and(iv) existing in the form of thin film/membrane for direct applications,for example,as sensors.This review discusses the oriented and crystalline SURMOFs fabricated by LPE approach,covering their preparation,growth mechanism,and characterization methodology as well as applications based upon the most newly updated knowledge.

Lubricating a bright future:Lubrication contribution to energy saving and low carbon emission

Both the academic society and the industry are hunting for new energy forms for the future.However,the world should not forget the conventional technologies that contribute to the sustainable society by technical innovations.Among them,lubrication plays a significant role in energy saving and in low CO2emission by increasing the fuel efficiency and by prolonging the service life of machines.With the advance of novel synthetic approaches,and nanoscience and technologies,novel lubrication oils and additives and their formulations are being developed to reduce friction and wear,and novel surface treatment routes and surface coatings are invented and provide more efficient lubrication.These technologies create tremendous chances for machines to work more efficiently with low energy consumption.Here we review the recent progresses and challenges associated with some novel lubrication techniques that include novel surface treatment(such as texturing,high-performance nanocomposite coatings,adapting coating),tribology design(solid and liquid lubrication),energy-conserving engine oil and novel lubricants and formula(such as ionic liquids,low S,P content additives)which are to be adopted to enhance the fuel efficiency to achieve energy saving and low carbon emission.There is increased demand to replace fossil lubricants by degradable green lubricants.Specially designed coatings can reduce drag significantly during navigation of both airplanes and ships.All these aspects will be also reviewed in the paper.

Dynamic metal patterns of wrinkles based on photosensitive layers

Regulating metal surfaces with micro-/nanoscale structures is of great significance for both material science and potential applications.However,the intrinsic properties of metals,such as fixed isotropic moduli and inflexible structures,in a sense present major limitations in developing next-generation smart patterned surfaces.In this work,a facile and general patterning strategy is proposed to endow insensitive metal surfaces with controllable spontaneous topologies and dynamic performance by exquisitely introducing an essential photosensitive interlayer.The arresting anthracene-containing photocrosslinking interlayer can selectively predetermine the anisotropic property of compliant bilayers without damaging metals’homogeneous properties,and realize a changeable stiff/soft layer.Furthermore,the mechanical transition mechanism of the self-adaptive wrinkling modes in metalbased trilayer systems is revealed to pave the pathway for regulating functional wrinkled metal surfaces.This photodriven metal patterning strategy can promote the development of brand-new methods for tuning the instability of multilayered materials,and be potentially applied in smart optical devices with dynamic reflectance,including light gratings and"magic"mirrors.

Analytical investigations and fuzzy logic-based modeling of the impact resistance of aluminum-epoxy laminated composites

In the present paper, Charpy impact resistance of aluminum-epoxy laminated composites in both crack divider and crack ar-rester configurations has been investigated. In both configurations, an analytical investigation has been carried out to evaluate the effects of layers thickness on impact resistance of the specimens. A model based on fuzzy logic for predicting impact re-sistance of the specimens has been presented. For purpose of building the model, training and testing using experimental re-sults from 126 specimens produced from two basic composites were conducted. The data used for the input data in fuzzy logic models are arranged in a format of 7 input parameters that cover the thickness of layers, the number of layers, the adhesive type, the crack tip configuration, the content of SiC particles, the content of methacrylated butadiene-styrene particles and the number of test trial. According to these input parameters, in the fuzzy logic model, the impact resistance of each specimen was predicted. The training and testing results in the fuzzy logic model have shown a strong potential for predicting impact resis-tance of aluminum-epoxy laminated composites.