bluuebunny/crossref_metadata_2025 huggingface dataset:
Retrofitting Options for Un-Reinforced Brick Wall Subjected to Impact Load
Authors: Mohamad Nor Norazman , Mohd Noor Mohd Azizul , Yusof Mohammed Alias , Zaidi Ahmad Mujahid Ahmad , Abdullah Shohaimi
Published: December 2012

In this research we investigate the possibility of enhancing the way brick walls can be retrofitted in an economical manner and become more resistant to blast impact. Retrofitting a method usually done on constructed walls; however, the same strengthening procedures can also be applied to a new construction project. In this research we investigate three methods of reinforcing brick walls against blast impact. First, reinforcing the brick layer using carbon fiber strips only without epoxy, with the fiber being placed on the bare bricks before it is plastered with mortar finishing, second, reinforcing the brick wall by placing CFRP onto the bare bricks and fixing with epoxy prior to finishing or being plastered over with mortar, and third, retrofitting the outer surface of a finished, or plastered, brick wall with CFRP and fixed with epoxy as is commonly done. The impact test was conducted using a drop weight released at a fixed height to simulate blast energy of an explosion. The effects of the test on all the samples were observed to identify failure patterns. Flexural testing was also conducted to observe how the samples perform under normal flexural loading. It was discovered that the second option, i.e. placing the CFRP on the bare bricks and fixing with epoxy before it is finished or plastered over with mortar, performs the best. This is due to the CFRP being firmly fixed before mortar finishing, causing the CFRP to be held steadily in place during the impact, thus, helping the wall to resist the impact load. With the third option, the CFRP was able to resist the impact but, as has been observed in other studies, the CFRP delaminates from the wall. The first option does not work very well since the mortar is unable to perform as well as the epoxy in holding the fiber to the wall to resist the impact force. Thus, for plastered brick walls, it is better suited for it to be reinforced by FRP under the finished mortar rather than on it, thus reducing the problem of delaminated FRP from the wall surface.
Analysis on Functionally Graded Material Coating Interface Crack
Authors: He Bo , Sun Chang Qing
Published: December 2012

It is assumed that the physical parameters of functionally graded coating material accords with the variation of degree n polynomial, and based on this material model, the behavior of crack fracture on the interface of functionally graded coating is studied. The results show that when the functionally graded coating structure bears a tension load, stress intensity factors of mode I and mode II exist at the same time generally, and the intensity factor of mode I occupies a leading position all along. Besides, when the elastic modulus ratio of the base to the functionally graded coating top is 5 and the elastic modulus of functionally graded coating varies linearly, the stress intensity factor of interface crack is the smallest, and with the increasing of elastic modulus ratio, the optimal non-uniform parameter tends to be larger than 1.
Low Hydrogen Pressure Induced High Anisotropy in HDDR-Treated Nd13Fe75Co4B8 Powders
Authors: Han Guang Bing , Fu Shuang
Published: December 2012

High anisotropic Nd13Fe75Co4B8 magnetic powders are obtained with low desorption H2-pressure of the hydrogenation disproportionation desorption recombination (HDDR) process. Scanning electron microscopy (SEM) indicates a lamella structure in the 20 kPa desorption H2-pressure HDDR products and may be related to the high anisotropy. The magnetic powders with a desorption H2-pressure of 20 kPa have the magnetic properties of Br =0.86 T and Mr/Ms =0.81.This shows that the H2-pressure has great effect on the formation of crystal texture in the HDDR Nd-Fe-B powders.
Paper and Board Pigment Coating Raw Materials – A Review of some Recent Innovative Novelties
Authors: Xiao Na , Pu Jun Wen
Published: December 2012

The intention of this paper is to review of some recent innovative novelties about paper and board pigment coating raw materials. First an overview is given of “traditional” coating raw materials and the coating process. Then new starch based pigments and binders as well as novel plastic pigments are reviewed regarding their effect on coated paper properties. Finally it is concluded that further innovations and research are needed.
Erosion Experimental Study on Organ-Pipe Nozzles in Air
Authors: Li Feng , Han Duan Feng
Published: December 2012

Experiment of aluminum block erosion using organ-pipe nozzle was carried out in air. The erosion effects of water jet were used to evaluate the performance of organ-pipe nozzle. The experiment and corresponding data were used to analyze the effects of nozzle configuration, jet pressure, standoff distance. Results have shown that the organ-pipe water jets are much more effective in aluminum block erosion.
ME Molecular Dynamics Simulation of the Sintering Process of the Porous ITO Material
Authors: Zhou Xiao Long , Cao Jian Chun , Feng Hao , Cao Yu , Fan Yong Jun , Chen Jing Chao
Published: December 2012

Simulated the sintering process of the porous ITO gas-sensitive material with Materials Explorer 5.0. Observed the the process of neck formation and growth, grain growth and pore shrunk. Than, compared the result with experimentation. We found that the simulation results were similar to the microstructure photos. At the same time, we could observe the migration process of atoms in simulation results which we cannot observe in actual experiment. It proves that we get the theory basis of the experiment result estimate and proved the guiding effect of molecular dynamics simulation to the actual experiment.
Numerical Simulation of Bionic Wing for Drag Reduction
Authors: Zhang Li Hong , Li Wei Jie , Yin Ji Xin
Published: December 2012

According to the presence of the rounded protuberances or tubercles located on the leading edge, a similar leading edge of humpback whale pectoral fin with the “paraganglioma” has been made on the leading edge of NACA63-210 wing, an bionic NACA63-210 airfoil is designed with convex-concaved leading edges, and the 3-dimensional flows around the bionic wing are simulated for the drag reduction purpose.
Optimization Design of Forging Die for Supporting Bar Based on DEFORM-3D
Authors: Fu Lei , Lin Li
Published: December 2012

On the basis of analyzing the process of supporting bar forging conform, the 3D solid geometries modeling of billet and die were constructed by SOLIDWORKS software, the distributions of die stress and contact stress on the process of supporting bar forging conform were analyzed by using DEFORM-3D program. The working life of the die punch was assessed. The die structure was optimized based on the simulation results, and the forging defect of the improved work piece could be well controlled and the die working life was improved to about 10%.
Phase Field Simulation of Solidified Multiple Grains
Authors: Guo Hong Min , Wei Tao , Yang Xiang Jie
Published: December 2012

A phase-field model based on the Ginzburg-Landan theory and KKS model is used to simulate the dendrite growth of multiple grains for Al-Cu alloy. The influence of solidification latent heat and undercooling on the growth of equiaxed dendrite, solute distribution and temperature distribution were studied. The results show that the dendrite has well-developed and the competitive growth between grains more intense with the increasing of undercooling. The release of solidification latent heat restrain dendrite growth to a certain extent, which led to the less developed growth of dendrite solidified in non-isothermal conditions than that in isothermal conditions.
Effect of Coil Parameters on Rivet Deformation in Low Voltage Electromagnetic Riveting
Authors: Deng Jiang Hua , Tang Chao , Zheng Yi Ming , Zhan Yan Ran
Published: December 2012

Electromagnetic riveting is a kind of energy conversion technology and forming coil is the key component of energy conversion. Coil parameters include the turns and wire cross section size. The effects of coil parameters on discharge current, riveting force, rivet deformation degree and energy conversion rate were investigated by experimental method in low voltage electromagnetic riveting. The results show that with the coil turns increasing, coil inductance increases, discharge current amplitude decreases, cycle increases, rivet deformation degree increases and the energy conversion rate improves when the coil wire cross section size is the same. And with the coil wire width increasing, the coil resistance decreases, discharge current amplitude increases, rivet deformation degree increases and the energy conversion rate improves when the coil turns is same. By rational design of coil turns and wire section size, low voltage electromagnetic riveting is an effective way to realize deformation of strain rate sensitive material TA1 rivets.
Research on Algorithm of Forming Limit Height in Semi-Ball Bottom Cylindrical Deep Drawing
Authors: Chen Kang , Liu Hui , Peng Cheng Yun
Published: December 2012

With physical experiments and numerical simulation about semi-ball bottom cylindrical parts and flat-bottomed cylindrical parts, we got the thinning law about spherical bottom of semi-ball bottom cylindrical parts, and got forming limit height difference of semi-ball bottom cylindrical parts and flat-bottomed cylindrical parts under the same conditions. In accordance with the principle of constant volume, the cylindrical ball height of semi-ball bottom cylindrical parts can be converted to draw from the cylindrical part height of the flat-bottomed cylindrical parts, which introduced a method of calculating the forming limit height of semi-ball bottom cylindrical parts. Through practical examples, this algorithm is feasible.
Numerical Simulation Research on Warm Forging Process for Spur Gear with Large Module Based on Floating Die Method
Authors: Yan Ke Long , Jin Jun Song , Wang Xin Yun , Xia Ju Chen , Li Jian Jun
Published: December 2012

The warm forging process of spur gear with large module using floating die set was studied in the paper. The influence of process parameters such as billet temperature, web position, web thickness, frictional factor on the filling of die cavity and forging load were investigated by finite element method. It was concluded that the corner filling of gear can be improved by using free floating die. The forging load decreased with the increase of billet temperature or the decrease of frictional factor. The best web position for die cavity filling was that the web was located in the middle of the forged part.
Research on Intelligent Precise Pass Design Algorithms
Authors: Li Guo Chang
Published: December 2012

How to build a stable pipe roller design algorithm system has become the difficulty of modern steel pipe roller design. Although the theory researching cold bending forming is more now, but the theory used to guide pass design is less. This paper studied and established the new rolling process model based on spline finite strip theory. It’s good to Shape the way time and build the chain storeing deformation way Agent structure in transition region. It helped to realize intelligent single channel cold bending forming a stress and strain description. And it is usefull to establish forming theory and the parameters contact of the pass design. In a word, it provided the theory basis for the precise pass design.
Research on the Forming Process of the Y-Shaped Tube Based on ABAQUS
Authors: Zhang Ling Yun , Pan Ya Lin , Li Zhen Jun
Published: December 2012

ABAQUS software is used to simulate the stamping process of the Y-shaped tube to study the feasibility of stamping forming. The simulation results are analyzed to study how fabrication holes affect the ability of sheet metal forming. The results show that it is possible to form the Y-shaped tube by stamping; fabrication holes with reasonable size and location can improve the distribution of stress and strain, and enhance the limit deformation ability of the sheet.
Model of Shear Slipping Deformation and its Cutting Energy Consumed for High Speed Machining
Authors: An Hu Ping , Rui Zhi Yuan , Wang Rui Feng , Zhang Zhi Mei
Published: December 2012

The characteristics of serrated chips were analyzed using the theory of shear-slipping deformation at high speed cutting, with geometric and mathematic models of the chip built. Deformation of continuous chip for scissile metal materials can be analyzed and controlled by analogous methods that are employed at normal cutting speed. Geometrical model about serrated chip for difficult-to-cut material under orthogonal cutting condition is offered by proper simplifying. The nonlinear equations of indices related to some factors for measuring deformation degree of chip have been ascertained. Based on the condition fo forces equilibrium with respect to single serrated chip at the moment when it is to be in shear instability, forces equilibrium equations are obtained, with shear force and shear velocity as well as friction force and flowing velocity for a chip segment found. Finally, energy equations of cutting are acquired from deformation energy and friction work consumed in the course of chip formation, which can be offered to the further study of mechanism of high speed machining and the design of high speed machine tool.
Study of the Impact Toughness Experiment of SiCp / Al FGM
Authors: Li Jin , Li Liang Yi , Zhou Chun Ling
Published: December 2012

This paper includes the result about the traditional preparation process on the basis of improved powder metallurgy method by using the hot press molding process. The aim of the process is to enhance the preparation of 5,7,10 body size of SiCp / Al functional graded composites. Moreover, the performance of impact toughness has been addressed and analyzed through solid study. The result can be concluded as following: The preparation via vacuum hot pressing process of SiCp / Al FGM has been performed good enough to reduce the cost of secondary processing; 5 SiCp/Al FGM shows better impact toughness properties in the test.
Preparation of Al2O3/Cu Composites by Internal Oxidation in Cu-Al Alloy Sheet Processing
Authors: Wu Rui , Zhang Dan Wen , Sun Juan , Ren Feng Zhang , He Qing Chuan
Published: December 2012

Internal oxidation Cu-Al alloy sheet processing has been used to prepare dispersion-strengthened Al2O3/Cu composites. A new technique has been developed that successfully avoids mixed Cu-Al powder preparation, H2-reduction, and sintering processes. The microstructure and phase were investigated by metallurgical microscope, SEM, and TEM. Holding-time, internal oxidation temperature and thickness of Cu-Al alloy sheet were the three key factors with regard to preparing Al2O3/Cu composites by internal oxidation in Cu-Al alloy sheet. The mechanical characteristics and electric properties of Al2O3/Cu composites sheet and hot-extruded rod were examined. The results show hot extrusion process enhances microhardness and ultimate tensile strength to a higher level with and exerts a little influence on high electrical conductivity.
Proportional Crown Rolling for Single Rough Stand in Semi-Continuous Hot Rolling Strip
Authors: Zheng Shen Bai , Zhou Sen , Wang Hui , Song Zhuo Fei , Li Hong Bin
Published: December 2012

According to the status of rolling middling stock without crown control on the single rough stand in semi-continuous hot strip rolling in domestic, the advantages and the working mode of middle plate rolling with proportional crown are introduced. Finally, the ways to improve the existing rough mill with CVC technology are discussed.
Numerical Simulation on Interface Crack Propagation for Non-Uniform Welded Joint
Authors: Zhang Xiang Hong , Shen Can Duo , Sun Chang Qing
Published: December 2012

Maximum normal stress criterion can be used to determine the cracking angle in the uniform and non-uniform zone. According to this theory, the propagating process of the crack in non-uniform composite material is simulated based on the finite element method. The results show that the crack advances wave-like and basically along the direction perpendicular to the maximum normal stress, which is of great guiding significance for the fracture resistance of such kind of structure.
Characteristics of Surface Microstructures for Welded Joint of 7A52 Aluminum Alloy before and after Surface Nanocrystallization
Authors: Xie Rui Jun , Lu Yao , Chen Fu Rong , Shi Zhi Ming
Published: December 2012

The surface nanocrystallization process by high energy shot peening (HESP) was carried out on the TANDEM MIG welded joints surface of 7A52 aluminum alloy after artificial aging. The microstructure features of welded joints surface layer were systematically characterized by using optical microscopy (OM) ,transmission electron microscopy (TEM) observations and X-ray diffraction (XRD) analysis. Based on the experimental observation, the banded texture of 7A52 aluminum alloy base metal was eliminated after HESP. After 50min of HESP processing, the thickness of deformed layer in the base metal (BM), weld metal zone (WM) and heat affected zone (HAZ) was 50μm, 70μm and 60μm separately. Obtained from the TEM micrographs, the average grain size of surface layer in the base metal, weld metal zone and HAZ was about 20nm, 26nm and 32nm respectively. The size of grain in the weld metal zone and HAZ was larger than the base metal. Moreover, the distribution of nanocrystalline in the weld metal zone and HAZ was uneven compared with the base metal.
Vacuum Brazing of GH2132 Superalloy Using BNi-2+BNi-5 Composite Filler
Authors: Li Rui Feng , Yu Zhi Shui , Qi Kai
Published: December 2012

In order to overcome the over formed intermetallic compound and the grain boundary penetration phenomenon in superalloys brazed joint using BNi-2 filler, the three variable portion of BNi2+BNi-5 composite filler is used to vacuum braze GH2132 superalloy. The results showed that the addition of BNi5 filler can decrease the formation of intermetallic compounds. For composite brazing filler of BNi2+40%BNi5, the brazing seam mainly composes of solid solution phase. The amounts of intermetallic compounds increased with the increase of brazing temperature and brazing clearance. The microhardness of the intermetallic compound is about 380~400 HV which is detrimental to the mechanical properties of the brazing joint.
Dynamic Anti-Plane Characteristic for a Quarter-Infinite Piezoelectric Medium with a Cylindrical Lining
Authors: Sun Li Li , Song Tian Shu , Liu Jian
Published: December 2012

Use the mirror method to transform the quarter space to the whole space under the complex coordinate system, and with the help of the boundary conditions around the cylindrical lining to solve the unknown coefficient. To do some numerical calculations of the dynamic stress concentration factor and the electric field intensity concentration factor around the cylindrical lining by using the program. In the numerical calculations stage, by changing the medium’s parameters, the structure’s geometry influence and the frequencies of incident wave to obtain more results on dynamic stress concentration factor (DSCF) and electric field intensity concentration factor (EFICF).The calculating results indicate that, under the action of SH wave the DSCF and EFICF around the cylindrical lining are similar to each other, and regularly distributed along the edge of the cylindrical lining. While the magnitude of DSCF and EFICF are larger than any other situations when the frequency of the incident wave was low. And the results are similar to results of the whole space condition too.
Influence on the Stress of Pavement with Crack in Base from Flexible Transition Layer under Dynamic Loading
Authors: Tu Shuai , Sha Ai Min
Published: December 2012

After cracks appear in the semi-rigid base layer, the stress mode of pavement structure transits from infinite continuum to limited size board, and the cracks become stress concentration areas. Based on the practical tire contact pressure and contact area, this paper establishes the C3D8R model by ABAQUS, to calculate and analyse the influence on the base cracks extension from graded gravel transition layer under half-sinusoid load. Analysis shows that the graded gravel has excellent stress dissipation ability. Whether there are cracks in the base, the graded gravel transition layer between asphalt surface layer and semi-rigid base layer could greatly reduce the tensile stresses in the bottom of semi-rigid base and subbase layers, improve the road bearing level, delay and avoid the cracks extension to deep road and prolong the road service life.
Research on the Mechanism between No-Smooth Surface, Desorption and Friction Increasing Based on Bionic
Authors: Shen Xiao , Fu Zhou Yu , Su Chun Jian , Sun Zhao Yang
Published: December 2012

Tribology behaviors play an important role in logistics, the researches of bionic tribology focus on desorption and friction increasing in rencent years. In order to reveal the mechanism between biological characteristics and tribology behaviors, this paper studied the typical no-smooth surface of animals, the analysis result showed that the no-smooth body surface of dung beetle greatly impacted its desorption, but the no-smooth foot surface of tree frog and locust played an important role in friction increasing. The similar no-smooth surface could have both function of desorption and friction increasing under the different conditions. Comprehensive analysis of no-smooth surface was done by simulation technology and experiment research, and revealed the mechanism between no-smooth surface, desorption and friction increasing, which opens up a new way for the development of bionic tribology and also provides technology for the improvement of logistics equipments.
Study on Failure Mechanism of Steel Wire Wound Reinforced High-Pressure Hose
Authors: Gu Fan , Sun Jia Quan , Wang Dan
Published: December 2012

For steel wire wound reinforced high-pressure hose, the static load test under internal pressure and fatigue test under combined effect of internal pressure and periodic transverse load were carried out. Test results show that water seepage or leakage on the pressing steel sleeve or on hose body itself, and bulging on hose itself near steel joint would lead to performance failure, which can be regarded as the performance failure criterion for steel wire wound reinforced high-pressure hose.
The Impact of Drying Methods on Paper Physical Properties
Authors: Zhao Shu Lei , Wei Zheng Yuan , Ding Xiao Tian , Lin Qiang
Published: December 2012

This paper experimentally examined the impact of four different drying methods (free drying, press drying, vacuum drying and impingement drying) on paper physical properties including roughness, elongation, air permeance, tearing resistance, tensile index and bursting strength. The handsheets materials are HWBKP (Hardwood Bleached Chemical Pulp), SWBKP (Softwood Bleached Chemical Pulp), CTMP (Chemical Thermo mechanical Pulp) and ATMP (Advanced Thermo Mechanical Pulp). Good experimental data were obtained for the four pulps under different drying conditions. The results of our investigation indicate that press drying have lower surface roughness, elongation and air permeance but higher tearing resistance; the vacuum drying have higher roughness, tensile index and bursting strength; the impingement drying have lower tearing resistance, tensile index and bursting strength but higher elongation and air permeance. Selection of different drying conditions for effective productivity and quality improvement potential is proposed as a direction for the future dryer design.
Preparation and In Vitro Drug Release Studies of Arginine Loaded Starch Microspheres
Authors: Zhu Min Peng , Li Su Hong
Published: December 2012

Epichlorohydrin crosslinked starch microspheres (ECMs) were synthesized with soluble starch as a raw material and epichlorohydrin as a crosslinker. The characteristics of ECMs were investigated by Scanning Electron Microscopy (SEM) and Fourier Transform InfraRed spectroscopy (FT-IR).The drug loading and in vitro release properties of ECMs were studied using arginine as a model drug. The results indicate that ECMs have a spherical morphology with average diameter about 7μm. The drug loading studies show that after absorption for 1.5 h, the largest amount of drug (drug loading 31mg/g) is loaded when the quantity ratio of ECMs to arginine is 2. In-vitro release studies indicate that the ECMs are effective in controlled releasing arginine over an extended period of about 25 h.
Electrochemical Behaviours of Scutellarin at Multi-Wall Carbon Nanotubes Modified Glassy Carbon Electrode
Authors: Cai Zhuo , Yue Wei Chao , Gan Jing Ni , Peng Yue , He Xiao Liang
Published: December 2012

A multi-wall carbon nanotube modified glassy carbon electrode (MWCNTs/GCE) has been prepared. The electrochemical behavior of scutellarin at the modified electrode and its electroanalytical method have been studied. It was showed that in 0.20 mol/L Na2HPO4-NaH2PO4 buffer solution (pH=7.4) MWCNTs/GCE exhibited excellent catalytic and enhancement effect on the electrochemical oxidation of scutellarin, the sensitivity increaced 23 times compared with that at bare GCE. The measurement parameters were optimized. Under the optimal conditions, the linear range of scutellarin concentration was 4.0×10-6-1.0×10-4 mol/L (R=0.9991) with a detection limit of 8.2×10-7 mol/L(S/N =3), and the RSD for 4.0×10-5 mol/L scutellarin solution was 1.8% (n=11). This method was successfully used in the determination of scutellarin in injection and tablets.
Preparation and Properties of Organo-Montmorillonite Modified R-122 Nanocomposite
Authors: Huo Chun Qing , Gu Hong Juan , Yu Zai Qian , Zhang Long
Published: December 2012

An OMMT (organic montmorillonite) was prepared by ion exchanging between Na-montmorillonite and cetyl trimethyl ammonium bromide (CTAB) and was applied to modify Dicyclopentadiene Dioxide Epoxy(R-122). FT-IR spectra showed that the organic molecules had intercalated into the layers of MMT successfully, X-ray diffraction illustrated that the spacing of layers of MMT increased from 1.43 nm to 3.85 nm. R-122 composite was prepared with this nano-organic montmorillonite. When the content of OMMT was 4.0% (wt%), the impact strenth of the composite reached to the highest(21.2 J/m), which is 92.7% higher than the pure R-122 . Morphology of the fracture checked by SEM, reveals a depth depended distribution which generated more new surface, thus can absorb more impact energy. Differential scanning calorimetry(DSC) showed that the thermal stability of the composite had improved compared with the pure resin. And what’s more, the improvement of toughness doesn’t hurt the resin’s heat resistance, it may provid a new way to prepare high performance R-122 composites.
Preparation and Properties of Polypropylene/Expended Vermiculite Micro-Nano Composite
Authors: Shang Wei , Li Dong Li , Xu Wen Cai , Yu Xue Mei
Published: December 2012

Thermoplastics were prepared by melt blending using polypropylene [PP] and expended vermiculite ball-milled with VAE emulsion. The effect of vermiculite content and vermiculite particle diameter on the crystallization and mechanical property of PP were studied. The mechanical property of PP and the composites studied by using universal testing machine show that both mass fraction of vermiculite and particle size have consequences for mechanical property of PP, and when mass fraction of vermiculite and ball-mill 5 hours can acquire good mechanical properties. The two parameters are in agreement with morphology of the composites observing from the Scanning Electron Microscopy and polarized-light microscope. The results obtained from nonisothermal crystallization of PP and the composites, which were carried out using the differential scanning calorimetry technique, show that vermiculite with micro diameter block crystallization, while vermiculite with micro-nano diameter can induce crystallization and increase crystallization.
Application of a Mixture of Oxidized Multi-Walled Carbon Nanotubes and D-(-)-Tartaric Acid-Impregnated Silica Gel as Stationary Phases for Thin-Layer Chromatographic Enantioseparation
Authors: Peng Zhi Guang , Yin Dong Hong , Liu Jian Fu , Yu Jin Gang , Yang Xiao Na , Zeng Dong Ming
Published: December 2012

The oxidized multi-walled carbon nanotubes were prepared by a nitric acid treatment procedure, which were then used as additive in thin-layer chromatography stationary phases for resolution of ofloxacin, mandelic acid and 2-chloro-mandelic acid enantiomers. In a sharp contrast with pristine multi-walled carbon nanotubes/D-(-)-tartaric acid impregnated thin-layer chromatography plates, oxidized multi-walled carbon nanotubes/D-(-)-tartaric acid impregnated plates presented better enantioseparation effects for ofloxacin enantiomers.
Microstructure and Mechanical Properties of New Type Bainitic Carburized Steel for Gear
Authors: Liu Zhi Xue , Cheng Ju Qiang
Published: December 2012

This paper presents the microstructure, mechanical properties and carburized behavior of new type bainitic carburized steel. The results show that after new carburized steel is normalized at 920°C and tempered at 300°C, its microstructure consists of bainitic ferrite and residual austenite, and belongs to the carbide-free bainite or atypical bainite. Large or small cross-section size new carburized steel bar all have reached the performance requirements of Cr-Ni carbonized steel. The microstructure of new carburized steel surface consists of high carbon martensite and residual austenite after carburized and air-cooled, It retains austenite fraction of the new carburized steel and 18Cr2Ni4WA steel are about 18% and 38%, respectively. Carbon concentration gradient of new carburized steel changes smoothly and have ideal carbon concentration distribution. Effective carburizing surface depth of new carburized steel is about 0.6mm and is smaller than 18Cr2Ni4WA steel. The gear entities made of new carburized steel meet the technical requirements of heavy duty carburized gear.
Influence of Annealing Temperature on Microstructure and Properties of the Hot-Stamping Boron Steel
Authors: Hu Kuan Hui , Liu Xiang Dong , Tian De Xin , Feng Guan Wen , Sun Fang Yi
Published: December 2012

The effect of different annealing temperature on microstructure and properties of the hot-stamping boron steel were studied.The results show that the yield strength of the test steel is reduced with increasing annealing temperature, only at 790°C,the specimen yield strength increased slightly, and showed a significant downward trend after 790°C.The specimen tensile strength and hardness with the change of the same trend when annealing temperature changes.And through the test we can see,at 760°C ,the test steel has entered a two-phase region,the test steel gain ferrite and pearlite when it is annealed below the temperature,it is easy to appear martensite microstructure when it is annealed in the higher temperature,and lead to the strength and hardness of the rise.
Effect of Strain Rate on Dynamic Recrystallization Behavior for V Micro-Alloy High-Carbon Steel
Authors: Ren An Chao , Ji Yu , Zhou Gui Feng , Yuan Ze Xi
Published: December 2012

Isothermal constant strain rate compression tests on high-carbon steel are carried out under strain rate of 1s-1, 10s-1 and 50s-1 respectively and deformation of 0.7 using the THERMECMASTOR-Z thermal simulator at a temperature of 1000°C. The austenite grain morphology before and after deformation and the true stress-strain curves during the deformation process are analyzed. The experimental results show that increased strain rate can obviously contribute to the grain refinement, and when the strain rate is at low level (e.g. 1s-1)，increased strain rate can further help refine the grains. And under the same temperature conditions, as the deformation rate rises, peak stress will move toward the direction of strain increment，thus the dynamic recrystallization is not apt to occur.
Study on the Tensile and Impact Properties of 600MPa HSLA Steel at Different Temperature
Authors: Luo Hai He , Dong Han Xiong , Dong Zhong Bo
Published: December 2012

The microstructure, tensile and impact property of a 600 MPa HSLA steel plate at different temperature were investigated by tensile and impact tests, metallographic observation, SEM and EDX analysis. The results indicated that the microstructures of the steel after tensile tests were mainly the bainites. As the temperature increased from 300°C to 650°C, the yield strength and tensile strength decreased, the elongation and reduction of area increased, but this steel had a relatively stable tensile property below 400°C. Moreover, as the temperature reduced from 20°C to -80°C, the impact toughness was gradually decreased, and the ductile-brittle transition temperature of this steel was obtained at -57.75°C by using Boltzmann function fitting.
Mean Strain Effect on the Cyclic Stress-Strain Behavior of Steel Structure Materials Q235
Authors: Guo Yi , Luo Yun Rong , Wang Qing Yuan
Published: December 2012

The low cycle fatigue (LCF) behavior of Q235 steel under mean strain control has been investigated. A serious of the strain controlled cyclic loading experiments with several combinations of strain amplitudes and mean strains have been performed. Significant cyclic hardening and mean stress relaxation were observed in all cases. Fractography by scanning electron microscopy (SEM) was used to determine the LCF failure mechanisms and fatigue crack propagation modes of the Q235 steel.
Thermodynamic Characterization in Intercritical Annealing Process for Dual-Phases Steels
Authors: Fang Fang , Wang Hui , Yin Yun Yang , Lin Cheng Jiang
Published: December 2012

The theoretical prediction of chemical composition, the range of main elements and austenite alteration affected by intercritical annealing temperature were conducted by thermodynamic calculations, which agree with the experimental results. When fixing carbon content at 0.1% and calculating temperature at 1000K, to achieve α+γ phases without cementite or graphite, Al must be less than 1.13%, Mn be 1.25~7.5% and Mo be less than 0.7%. The calculated Ae3 is 54°C higher than the measured Ac3, and calculated Ae1 is 14°C higher than Ac1. The intercritical annealing temperature for DP590 steels with Al as main alloying element can be calculated by setting ratios of α:γ in 70:30, and the calculated value of 807°C was close to the experimental results of 800~840°C.
Effects of Continuous Annealing Process on Microstructures and Properties of C-Mn-Si Bearing Cold-Rolled TRIP Steel
Authors: Wang Li Hui , Tang Di , Jiang Hai Tao , Liu Ji Bin , Chen Yu
Published: December 2012

Effects of continuous annealing process on microstructure and properties of Si based cold-rolled TRIP Steel were studied. The results show that the TRIP effect is more obvious on the condition of 800°C with 120s annealing process and 400°C with 520s aging treatment than others progress. The yield strength of the tested steel is 405MPa, tensile strength is 670MPa, elongation is 32% and strain hardening exponent is 0.230. The microstructures are ferrite, bainite and retained austenite and the volume fraction of retained austenite for the tested steel is 9.20%.
The Effects of Fiber Volume Fraction on the Vibration Damping Characteristics of Three-Layer-Connected Biaxial Weft Knitted Fabric Reinforced Composite Materials
Authors: Liu Jing Xue , Li Jia Lu
Published: December 2012

The paper presents an analysis of the vibration damping properties of three-layer-connected biaxial weft knitted fabric (TBWK), which are constituted of carbon fibers as inserted yarns and polyester yarns as knitted yarns impregnated in an epoxy matrix with resin transfer molding (RTM) technique. Damping parameters were investigated using beam test specimens and an impulse technique. Several vibration parameters were varied to characterize the damping behavior in different amplitudes, natural frequencies and vibration modes. The results obtained show that the damping ratio of TBWK composites decreases with the increasing of fiber volume fraction in all the three vibration modes. The vibration test also indicates that the natural frequency of the TBWK composites increases with the increasing of fiber volume fraction (Vf) in all the three modes.
Characterization of the Interphase in Carbon Fiber/Epoxy Composites Using Force Modulation Atomic Force Microscope
Authors: Xue Hao , Fu Hong Jun
Published: December 2012

In order to describe directly interphase properties of composite, force modulation of atomic force microscopy is adopted to study the cross-section of unidirectional carbon fiber/epoxy composites systematically. Research results indicate that in force modulation mode of AFM, relative stiffness of various phases distinct in distribution, which is described by probability histogram of relative stiffness. By comparison of probability histogram of relative stiffness nearby interphase of untreated and oxidation treated by ozone composites, the relative stiffness change oxidation treated one was more obviously to be found than the one untreated. Indirect show that obvious interphase formed by oxidation treatment. This method plays a valuable role in assessment of interphase strength of carbon fiber/epoxy, as well as in instruction composite production technology.
Effect of TiN Addition on the Microstructure and Mechanical Properties of Ti(C, N)-Based Cermets
Authors: Lei Hai Yan , Feng Ping , Zhang Xiao Ming , Zheng Teng Biao
Published: December 2012

The effect of titanium nitride addition on the microstructure, porosity and mechanical properties of Ti(C, N)-based cermets were investigated in this work. Results show that cermets have typical core-rim microstructure, the grain size of hard phase refines and the porosity increases with the addition of titanium nitride content. The transverse rupture strength reaches maximum at about 15wt.% titanium nitride. The hardness declines with the incremental titanium nitride content.
Effect of Co-Doping on Electronic and Magnetic Properties in Ti2NiAl Heusler Alloy
Authors: Wu Bo , Yang Xiu De , Zhang Song
Published: December 2012

By using local spin density approximation (LSDA) scheme within the density functional theory (DFT), the structure, magnetism and electronic properties of Co-doped Heusler alloy Ti2NiAl with Hg2CuTi- and Cu2MnAl-type structure are comprehensively investigated. The results revealed that whole of the doped alloys with Hg2CuTi-type structure are ground configurations and half-metallic. With the increase of Co-doped concentration, the lattice constants and total magnetic moments in per unit are changed linearly, and the discrepancies of total energy between Hg2CuTi- and Cu2MnAl structure are also enhanced. Analysis on density of states (DOS) revealed that the Fermi level should gradually move to high-energy orientation with increasing Co content due to stronger hybridization of d-electronic atoms.
Research on Coupled Effects of Alloy Elements for Precipitation Strengthening to Rupture Life of Single Crystal Ni-Based Superalloys by RBF Networks
Authors: Liu Xing Gang , Pan Xu , Li Jin Guo , Wang Yan Hui , Zhu Shi Zhe , Pang Yun Yang
Published: December 2012

This paper studies the coupled effects of alloy elements for precipitation strengthening to rupture life of single crystal Ni-based superalloys. Through setting up the Radial Basis Function model to predict rupture life, the generalization ability test indicated that this model has better precision and practicability. According to this model, utilizing the theory of parameter sensitivity analysis to quantitative analysis the interactive effects of different alloy elements and/or groups to rupture life, providing the theory basis and reference for the alloy design and productivity of single crystal Ni-based superalloys.
The Effect of Addition Mn on the Morphology of Fe-Rich Phase in the Al-1Fe Alloy
Authors: Yu Guo Jun , Peng Ji Hua
Published: December 2012

A flux with MnCl2 is used to control the morphology of microstructure in Al-1Fe alloys. An orthogonal test plan (L(33)) was employed to study the effect of the ratio of Mn/Fe, temperature and holding time on the morphology of the Fe-rich phase. Metallographic and image analys is techniques have been used to quantitatively examine the microstructural changes occurring with Mn addition. XRD analysis is employed to identify the phase of intermetallic compound in the alloy. It is found that when the ratio of Mn/Fe in the melt is located in the range from 1.5 to 2.0, the original needle like iorn phase can be transformed to be massive morphology, such as Chinese script, globule or polyhedral, and the area fraction of iron phase in the Al-1Fe alloy can be reduced by adding MnCl2 during the melt processing.
Connections of the Microstructure of the Fe-Al (25-33%wt.) with its Composition and Cooling Rate from the Liquid State
Authors: Sheshukov Oleg Y. , Ermakova Valentina P. , Marshuk Larisa A. , Smirnova Valentina G. , Kataev Vladimir V.
Published: December 2012

Laboratory researches of cooling rate influence on matrix structure, composition and quantity of nonmetallic inclusions in iron-aluminum alloys, containing 25-33%Al, are conducted. Thermodynamic modeling of composition and quantity of phases, which were formed in alloy system, containing Fe-Al-Si-C-O, for equilibrium conditions by means of the program complex ASTRA-4 (TERRA) is carried out. It is established, that irrespective of cooling rate the matrix has structure of intermetallic Fe-Al, and nonmetallic inclusions have platelet shape and composite of iron and aluminum oxy-carbides. It is confirmed, that ferroalloy with the optimal structure, necessary for receiving the high heat-resistance cast iron, should be cooled after smelting with the highest speed in these condition.
Preparation of Dispersion Strengthened Aluminum Alloy by High Energy Ball Milling
Authors: Cao Hui Qin , Luo Ji , Yang Wei Wei
Published: December 2012

In order to develop a high-strength aluminum alloy, alumina dispersion strengthened aluminum alloy was prepared by high energy ball milling on 2024 aluminum alloy powder in ethanol. The microstructure, particle size and distribution of the Al2O3 particles in the alloy were analyzed by FE-SEM; the mechanical properties were investigated. Results showed that alumina dispersion strengthened aluminum alloy was prepared successfully by high energy ball milling, the Al2O3 particles of several tens of nm in diameter were homogeneously distributed in the matrix grain and the spatial distance between particles was about 50-100nm. The yield strength and elongation of alumina oxide dispersion strengthened aluminum alloy were 489MPa and 7.9%.
Preparation and Water/Oil Repellency Properties of Waterborne Cationic Perfluorinated Polyacrylate
Authors: Yang Xiao Wu , Shen Yi Ding , Li Pei Zhi
Published: December 2012

A series of waterborne cationic perfluorinated polyacrylate (WCFPA) were prepared by the reaction of styrene (St), methacrylatoethyl trimethyl ammonium chloride (DMC), butyl acrylate (BA), octadecyl acrylate (ODA) and 2-(perfluorooctyl)ethyl acrylate (FEA) by soap-free emulsion copolymerization and then the films of the WCFPA were prepared. Their structure and water/oil repellency properties, such as surface property, water and chemical resistance of their membrane were characterized by fourier transform infared spectrometer (FT-IR), interfacial tension instrument (IT), contact angle (CA) and spot test. The results reveal that WCFPA was endowed with low surface energy of its film. It was also found that the fluorinated polyacrylate had outstanding water and chemical resistance. Increasing the FEA amount in the emulsion was as sociated with larger contact angle and better water and oil repellency.
Dynamic Absorption and Desorption Research of HPD722 Macroporous Resin for Flavonoids in Thlaspi arvense Linn Extract
Authors: Wang Li Sheng , Ma Rong Kai , Peng Mei , Liu Xu , Yang Hua , Li Xuan Hai
Published: December 2012

The impact of HPD722 macroporous resin on the dynamic adsorption and desorption of flavonoids in Thlaspi arvense Linn extract is studied. Obtained optimal conditions：the mass concentration of the sample solution is selected to be 4 mg•mL-1; while the flow rate of sampling is 1.30mL min-1; pH value is 4；50mL ethanol at a volume ratio of 70% is adopted as the desorption agent；the desorption flow rate reaches 3.47 mL•min-1. Under these conditions, the content of flavonoids increases from 5.09% to 21.91% upon purification by HPD722 macroporous resin.
Time-Temperature-Stress Superposition Principle: Brief Description and Application to Polymer Creep Behavior
Authors: Li Yong Hua , Jiang Cheng Kai
Published: December 2012

A new accelerated characterization model for creep performances was briefly introduced first, which considers both the effects of temperature and stress level, named time-temperature- stress superposition principle (TTSSP). TTSSP assumes that the influence of stress level on the intrinsic time is similar to that of temperature for the creep behavior, as well as damage and physical aging. The creep curves at different state can be shifted into a master curve at reference state using TTSSP. Then the long-term creep behavior of viscoelastic materials at lower temperature and/or stress level can be predicted from the short-term ones. Finally, TTSSP was used to investigate the nonlinear creep behavior of high-density polyethylene (HDPE). It was shown that the long-term creep behavior of HDPE can be predicted successfully.
Study on Preparation for Super Absorbent Polymer Using Cotton Waste
Authors: Tan Lei , Liu Zheng Qin , Liu Yang Yang
Published: December 2012

For the purpose of recycling of cotton waste cuttings and exploring the prospect of preparation for super absorbent polymer (SAP), the high viscosity carboxymethyl cellulose (CMC) was made from cotton waste first and then the SAP was synthesized by grafting acrylic acid (AA) onto the CMC with the potassium persulfate being as initiator, N, N'-methylene bis acrylamide as crosslinker. The impact of polymerization temperature, time, initiator dosage, AA concentration, crosslinker dosage, and neutralization degree on water absorbency of SAP was studied. The optimum conditions are mass ratio of AA and CMC 7.11 g/g, initiator dosage 0.03 g/g CMC, crosslinker dosage 0.2 g/100g AA, neutralization degree 80% and polymerization time 1.5 h at 70°C of the polymerization temperature. The water retention of the polymer is good and the water absorbency reaches up to 702.5 g/g.
Synthesis and Characterization of Mn-Doped Copper Chromite Black Pigments
Authors: Ye Ming Quan , Han Ai Jun , Chu Zhou Shuo , Che Jian Fei , Wang Chen
Published: December 2012

Mn-doped black pigments CuMnxCr2-xO4(x=0, 0.05, 0.10, 0.15, 0.20 and 0.25) were synthesized by precursor coprecipitation method, and characterized by TG-DTA, XRD, FTIR and colorimetric analysis. The TG-DTA curves showed the crystal transition temperature was at about 800°C and mass loss ended at about 450°C. The infrared spectra displayed vibrations of spinel phase. XRD patterns displayed the characteristic peaks of the tetragonal phase spinel structure and proved that Mn substituted Cr in the spinel crystal lattice. L*a*b* analysis showed that all samples are black pigments with blue intensity, and Mn-doping could strengthen the black intensity and weaken the blue intensity of such black pigments.
The Preparation and Characterization of AM/2-EHA/VTEOS Copolymer as Profile Control Agent
Authors: Tian Ming , Xu Yong Jun
Published: December 2012

In order to enhance oil recovery and avoid the profile control agents degradation in the alkali/surfactant/polymer composite solution in the oil layer, the copolymer of AM (basic monomer), 2-EHA (salt resistance monomer with large lateral group) and VTEOS(temperature tolerance monomer) was prepared by free radical copolymerization method as the profile control agent. FT-IR and 1H-NMR were used for the structure characterization. Thermo gravimetric analysis, Core/Sand pack experiments and water drive displacement tests of copolymer particles were used to evaluate the properties. The results shows that the copolymer particles have good thermal stability, alkaline resistance, anti-salt property and excellent blocking property as profile control agent.