bluuebunny/crossref_metadata_2025 huggingface dataset:
Geological and Geochemical Characteristics of Chang 7 Uranium-Enriched Hydrocarbon Source Rocks in Ordos Basin and the Possible Reasons for its Formation
Authors: Wei An Jun , Wu Bai Lin , Zhang Ben Hao , Song Zi Sheng , Wang Hai Tong , Wang Dan , Cun Xiao Ni , Sun Li
Published: May 2014

The Ordos basin Chang 7 hydrocarbon source rocks are the most important rock strata of premium oil source formed during the largest lake flood period of the terrestrial lacustrine. Our study found that the bottom of the rocks are rich in radioactive uranium. Element geochemical studies showed that the rocks are also rich in C, S, P, Cu, V, Mo and other pro-life elements but not rock-forming minerals-related lithophile elements Li, Zr, Sr, etc. Their uranium content has obvious positive correlation with phosphorus, sulfur, iron, organic carbon content, but not with major rock-forming elements. Petrography and scanning electron microscopy revealed the rocks are rich in pyrite, phosphate rock and striped organic matters. These features indicate that uranium enrichment and the presence of these minerals are closely related. The significantly positive correlation of the ratio of uranium to trace elements such as U/ (U+Ni) and U/Sc indicates that anoxic environment played an important role in uranium enrichment. Electron microprobe analysis found for the first time uranium ore and independent titanium-containing uranium minerals in phosphate rocks in the area. α radiation photography and sequential chemical extraction found that 50% of uranium present as independent uranium and its isomorphic minerals in the phosphate rocks, 20% is absorbed to pyrite and organic matter, and less than 10% is absorbed on clay minerals.
Facile Synthesis of Nickel Based Alloy Microtube by Using Spider Silk as Template and its Catalytic Property
Authors: Li Xiao Li , Sun Jin Li , Bao Yong Chao
Published: May 2014

Nickel based alloy microtube was prepared by utilizing spider silk as template via electroless deposition. The spider silk fiber was choosed as template which can be removed easily by heat-treatment and dissolving with sodium hydroxide solution. The nickel based alloy microtube was characterized by TG-DSC, XRD, SEM and EDX. SEM show that the microtube is about 600nm in outer diameter, 400 nm in inner diameter and more than 20 μm in the length. The catalytic activity of different structure Ni-P products was studied in liquid-phase hydrogenation of nitrobenzene reaction. The results show that the catalytic property of amorphous nickel based alloy is better than crystalline nickel based alloy and Raney Ni.
The Life Evaluation to Determine Remanufacturing Access Period of Telescopic Boom for Mobile Crane
Authors: Lu Feng Yi , Zhu Wei , Xu Ge Ning , Yang Ru Gang
Published: May 2014

In order to determine the remanufacturing access period of telescopic boom for mobile crane, it is needed to study one of its main failure forms—fatigue damage to predict remaining fatigue life which is regarded as parameter to remanufacture and foundation to make comprehensive evaluation. First of all, in certain period, the numbers of work cycles corresponding to different lifting loads for different rated lifting capacity of telescopic boom are collected, so that a set of data can be got as learning sample, then editing a neural network program and training it by entering the learning sample obtain the appropriate neural network weights, finally through inputting rated lifting capacity and lifting loads of telescopic boom needed life evaluation to the neural network program, the numbers of work cycles are obtained. Building on the principle of Miner fatigue damage accumulation and combining with the Paris-Eadogan equation, the formula of remaining fatigue life is deduced, and finally the graph of remaining fatigue life corresponding to different initial crack is drew. The results show that the initial crack effect on the remaining fatigue life largely and crack of 0.4mm should be tracked and monitored as a starting point, so remanufacturing the boom at an appropriate time ensures safe and reliable operation of mobile crane.
Research on Failure Criterion of Lattice Jib Structural System Reliability
Authors: Xu Ge Ning , He Shuai Lei , Yang Rui Gang
Published: May 2014

In Four-column limb lattice jib structure system as the research object, considering the structure and mechanical characteristics, combining with the allowable stress method, from the failure mode of static strength, stiffness, overall stability and local stability to build lattice jib structure system reliability failure criterion. Based on the influence of parameter perturbation calculation of four-column limb lattice jib structure system, get the length of the jib, lifting weight, jib elevation, hoisting load bearing point offset, the proportion of wind environment on the influence of different failure modes and failure change law, as the main failure mode of the decision to provide the basis and methods.
Wear of Coated Cutting Tool Based on AdvantEdge
Authors: Zhang Zhi Qiang , Gang Tie Qiang , Yi Yi Kai
Published: May 2014

In this paper, based on finite element simulation software AdvantEdge, the effects of different coating materials and thickness on the wear of cutting tools during the machining process have been studied. For the tools with coating materials of TiAlN, Al2O3, TiN, TiC, we can calculate the wear rate according to the Usui mathematical model of tool wear, and then consider thickness factor of TiC coating. Because of the lowest thermal conductivity, the workpiece cut by TiC coated tool will soften first and more over cutting time, it result in the lowest wear rate. And with the increase of coating thickness, the effect of "thermal barrier" is more obvious for the relatively thicker coating tool, but the relative sliding velocity between the chip and tool is increasing meanwhile, so a suitable coating thickness is necessary.
Reliability Design for Automobile Rear Axle by Perturbation Method
Authors: Han Shu Kui , Guo Rui , Cai Yi
Published: May 2014

In this paper, the application of reliability theory in the automobile rear axle has been studied. Essential theory and formulation for reliability estimate and design for rear axle are provided by perturbation method. The example in this paper has proved that the calculation result of the reliability design by using the perturbation method is very consistent with the real size of e-statistical rethsult. So, perturbation method can be widely applied in the rear axle’s design.
Sinterability and Expansion Property of Ceramsite Made with Lead-Zinc Mine Tailings
Authors: Wang Dong , Huang Jin Lou , Peng Hong Tao , Huang Jing Lu
Published: May 2014

Lead-zinc mine tailings were used to produce ceramsite by sintering method to reduce their environmental impact. The properties of tailings from Beishan Lead-zinc mine located at the north-west of Guangxi Province in southern China have been studied. The sinterability and expansion property of the main raw materials was studied during the controlled trial burn tests. The results show that lead-zinc mine tailings are not suitable for making ceramsite alone, and should be added with the clay material. The sintering temperature has a significant influence on expansion property. The optimum firing temperature to make ceramsite is from 1140 °C to 1150 °C according to the apparent density index, and the heavy metals are properly stabilized in ceramsite. It is a viable approach for making ceramsite with lead-zinc mine tailings and clay.
Research of DSP Code Generation Based on Matlab-DSP Integrated Design
Authors: Du Ru Jian , Liu Jun , Li Yan Song
Published: May 2014

The super capacitor can effectively prolong the operation of the energy storage system, improve its economic performance and power output capacity. But the design of the super capacitor is not perfect, the design method is also very troublesome.In this paper, through studying the different implementations of Matlab - DSP integrated design methods,I tried to find the optimal method to achieve the most simple and rapid Matlab - DSP integrated design. Build models in the Simulink, complete the design of the model, and convert it to DSP assembly language and download to the target board. The main process of this method is that the above steps. Apply this method in the design of the super capacitor , we can greatly speed up the development speed.
The Simulation Design of Umbrella Gasless Laparoscopic Device with Variable Cross-Section Spokes
Authors: Geng Kui Hua , Su Yi Yong , Zheng Guang Ping , Wu Dong Po , Su Wen Gui
Published: May 2014

A kind of umbrella gasless laparoscopic device with variable cross-section spokes is designed for the common problems of gasless laparoscopic devices. Under working conditions, the device can better simulate the abdominal shape of gas laparoscopic surgery, provide good surgical views, improve the stress conditions of the spokes and the abdominal wall and avoid the secondary injure to patients.The spoke, the key part of the device, is simulated by applying the analysis software ANSYS to obtain the ideal design size of its variable cross-section. Furthermore, physical prototype tests are done on the device, whose results show that the device can be opened as spherical and meet the design requirements.
Development of Desulfurization Agent in RH Refining Process
Authors: Chen Liang
Published: May 2014

Sulfur is a kind of harmful element in steel, and it is beneficial to molten steel to reduce the content of sulfur. On the basis of research, suitable desulfurizing agent and process parameters were chosen. The results of industrial test show that the average desulfurization efficiency is as high as 30%. In addition, there is a good result of T[O]&[N] control as well. With this testing program, the total content of FeO and MnO in ladle slag is bellow 12%, and it is beneficial to desulfurization. Increasing the content of CaO in desulfurization is conducive to desulfurization. On the other hand, There exists a serious problem in the test, and it is the erosion of RH immersion tubes, bottom of vacuum chamber, and refractory of ladle lining. In order to avoid or decrease this problem, basic refractory must be chosen.
Research on the New Missile Actuation System with Dual Independent Closed-Loop
Authors: Chen Hui , Fu Yong Ling , Chen Juan , Liu He Song
Published: May 2014

With the development of the advanced precision-guided missile and anti-missile system, high precision, high penetration ability and Low energy consumption have become an important direction for the missile. A new missile electro-hydraulic actuation system with dual independent closed-loop is put forward with the trend of high performance and energy-saving, and then the operating principle and process are discussed. Finally the accurate mathematical model is established, and the influence of the different basic pressure on the dynamic performance is analyzed. The simulation results show that the new proposed scheme has made great improvements in reducing the zero-control current of the system, but the efficiency and performance of the actuation system should be considered integrated due to the decrease of the dynamic performance, so it is practical for the future development of the missile electro-hydraulic actuation system.
Research on the Impact between Balls and Re-Circulating Mechanism of Ball Screws
Authors: Zhang Zuo Ying , Zhang Wan Li , Xu Chi
Published: May 2014

A Mechanical model of impact and contact between the ball and re-circulating mechanism in ball screw was brought forward according to the Hertz contact model and classical impact theory, along with the joint relationship of re-circulating mechanism and nut taken into account. Then the formula of the impact force and contact time was induced, which the elastic coefficient of restitution was considering in contact time calculation. Moreover, a special test unit was designed for contact time measurement and the contact time was measured. The result indicates that the new model proposed in this paper is closer to the practical situation than the old model proposed in literature. Based on works mentioned above, the influence of impact angle, parameters of structure and material on impact force was analyzed by numerical simulation.
Stability Analysis for Extendable Leg of Pump Truck
Authors: Zhao Er Fei , Cheng Kai , Wang Ning , Shi Zhan Yu , Zhang Pan Feng
Published: May 2014

There are mainly two areas of the lap part for the force transmission on the extension type retractable outriggers of the concrete pump truck, especially the bottom plate. If the side vertical plate at opening area isn’t designed properly, it may cause instability, which is really hard to be solved by analytical method. During structural checking of the leg with front-stretching type by ANSYS, the vertical plate at the area overlapped with the base is found to be out of convergence when load reaches a certain magnitude. Then the geometric nonlinear analysis is done by ANSYS and LS-DYNA respectively, and the results of them both verify the above conclusion. And the results of them are compared and analyzed. Finally the structure is improved to avoid buckling, and the improved structure meets the design requirements after the re-calculation. It also shows that the geometric nonlinear large deformation analysis is effective in solving the problem of buckling stability of complex structures.
Ground Penetrating Radar Technology and its Application in Civil Engineering
Authors: Huang Yun Yan , Han Ning , Wang Hong Xiang , Wang Zhao Ling
Published: May 2014

The master has more detailed and accurate geological data for the exploration work effectively guiding the design and construction of great significance. Ground Penetrating Radar is a high resolution in geological exploration technology, it can explore fault zone, fractured zone, rich with water, rock caves and other abnormal geological disasters have significant effects of exploration, through a careful analysis of radar images, and we can get more reliable information on the geology.
Experimental Research on the Influence of Transmission Parameters on the Transmission Performance of Magnetic Resonance Wireless Power Transmission Systems
Authors: Li Chang Sheng , Zhang He , Jiang Xiao Hua
Published: May 2014

Magnetic resonance wireless power transmission uses resonance strong coupling between the transmission and receiving terminals to realize a non-contact efficient supply of energy over large distance. The transmission power, efficiency and distance are confirmed by comprehensive function of the transmission parameters. By taking experimental means, the influence laws of loop transmission parameters, such as separation between coils, coil size, etc., on the transmission performance are studied in this paper. The experimental results show that the power high-efficiency and high-quality transmission does not depend on the large coil loop coupling coefficient and transmission power and efficiency may increase firstly and then decline as the separation between coils increases. The transmission performance can be optimized by increasing the coils diameter or wire diameter, and moreover, transmission systems with a high resonance frequency can produce high power and efficiency transmission over short distances.
Analysis of Temperature Field on Combining Friction Discs of Wet Clutch
Authors: Li Jie , Wang Xiao Yan , Jin Qi , Luo Jun Zhi , Yi Liang Hai
Published: May 2014

Because of overheat and over wear, the distortion and invalidation will be produced easily in combining friction discs of wet clutch of heavy vehicle transmission system. So the paper studies the sliding friction force of a pair of steel and friction disc, calculates the heat flow density, obtains the heat exchange function with axial symmetry, and establishes the finite element model of temperature field. And then the transient heat field simulation is analyzed, and temperature field distribution curves of combining pairs are obtained. Thus the connection is found between time and temperature along radial and axial direction, and temperature field characteristics are obtained with touch press, relative speed, and sliding time.
Foundation of 3D Coal Seam Model Based on the Incremental Insertion and the Shortest Diagonal Methods
Authors: Zhao Min Ning , Chen Ling Xia , Su Ying , Li Qing Yun
Published: May 2014

As the borehole data is sparse , the particle swarm neural network (PSO-BP) spatial data interpolation method is used for scattered data interpolation, which enhances the availability of the data and improves the accuracy of data interpolation. Furthermore, the incremental insertion and the shortest diagonal methods are used in modeling because the modeling speed is high and dynamically updating is convenient, finally, 3D visualization model of the coal seam on the base of Matlab language is realized.
Studies on Novel Satellite Navigation and Positioning System Anti-Jamming Architecture
Authors: Huang Wen Zhun
Published: May 2014

During the course of studying how to improve and optimize the anti-jamming ability of the satellite navigation and positioning system, the satellite channel was faced with many types of jamming signals. It is difficult to adopt one kind of jamming suppression technology to effectively suppress all kinds of jamming. In order to solve these problems, a new anti-jamming architecture for satellite navigation and positioning system is proposed. That is adopting the jamming cognitive method combined with the time-frequency domain jamming type recognition, power analysis and jamming DOA estimation. Also, the anti-jamming architecture design of the satellite navigation and positioning system is given based on the jamming cognition. Theoretical analysis and simulation results show that the anti-jamming architecture can detect the different jamming signals according to different jamming types, simplify the jamming suppression algorithm, grade and classify to suppress jamming signals.
Internal Impact Analysis of a Novel Controllable Metamorphic Palletizing Robot Mechanism
Authors: Wang Ru Gui , Chen Hui Qing , Li Ye Xun , Zou Qing Ming , Yuan Hua Qiang
Published: May 2014

Metamorphic mechanism would result in impact when it was changing from one configuration to the next. As a result, the internal impact force would bring about great vibration for the mechanism. What was more, it would make the mechanism be unstable. Therefore, the internal impact for metamorphic mechanism was expected to be analyzed. The controllable metamorphic palletizing robot mechanism was investigated in this paper. First of all, its kinetic characteristic was analyzed. In addition, the total momentum of the link which suffered impact was calculated. Furthermore, the impact force of the link was known. Finally, the relationship between the impact time when the mechanism was changing configuration and the momentum of the link was described through example study. The work of this paper provides some references for stability study of metamorphic mechanism.
Hydraulic Leveling Technology for Electro-Hydraulic Proportional Control Based on Fuzzy PID
Authors: Gao Tian Xiang , Gao Qiang , Li Yan
Published: May 2014

In modern military and civil technologies, platforms with equipment on them are often needed to be adjusted to horizontal position rapidly and precisely and keep the platforms stable at the same time. Most leveling systems are implemented with hydraulic system, and they are time-variant nonlinear systems. To leveling both rapidly and steadily with required precision, a PID control strategy based on fuzzy theory was proposed. Electro-hydraulic proportional valve control hydraulic system model was created and analyzed, transfer function of hydraulic legs was obtained and fuzzy PID controller was created in this paper. The proposed method is simulated in Simulink. The simulation result shows that fuzzy PID controller can adjust the platform to horizontal position rapidly and steadily, and improve system performance.
The Design of Motor Energy-Saving Controller Based on the Frequency Converter
Authors: Liu Song , Jiang Lian Zhi
Published: May 2014

This paper introduces a kind of motor frequency conversion energy-saving controller used for fan and water pump loads. Motor energy-saving controller mainly consists of two parts, controller and driver. The main functions of the controller are data collection, control algorithm and communication. The driver is mainly composed of inverter, switch and display instrument. According to the actual situation, if it needs a remote control, we can configure the remote console in the control room, in order to realize the remote control.
Calculation Methods of Obtain CH3+ Small Fragments by the Ring of C5H8O+
Authors: Chen Hong Bin , Zhu Ying , Wu Jie
Published: May 2014

Using the CIS(Configuration Interaction with Single Substitute) method, and 6-31+G (d, p) basis set, we calculated the frequency of excited state of cyclopentanone ion molecule. Studies on the possible way of obtain CH3+ small fragments by cyclopentanone ion. Judging from mass peak, there is ion fragments of CH3+, through the theoretical calculation, we have get that the fragments CH3+ by the dissociation products of C5H8O+ is the same to the fragmentation of the time-of-flight mass spectra excited by femtosecond laser. It can be preliminary judgment that C5H8O+ cleavage fragments may have CH3+ fragments in this vibration mode.
A Fuzzy PID Control Method for the Grasping Force of an Underactuated Prosthetic Hand
Authors: Li Qun Ming , Lv Ya Ping
Published: May 2014

The prosthetic hand which is the auxiliary equipment of the disabled people in the daily life must ensure stable grasping. Therefore, grasping force control with high accuracy and fast response is the most significant demand. With a conventional PID control, nonlinear dynamic and modeling error of prosthetic hand highly affect the control performance, causing deviation of desired force and slow response. A fuzzy PID control strategy is proposed for eliminating the influence of modeling error and implementing the grasping force control. The PID controller parameters are tuned automatically, on-line, to improve the control performance of the prosthetic hand system. The simulation and experimental results are presented to demonstrate the reliability and effectiveness of the proposed control scheme.
Cost Control of the Marine Diesel Based on Value Engineering
Authors: Tao Yong Hong , Yang Jing , Shi Jun
Published: May 2014

Cost control is an important measure to improve economic benefit of enterprises, while the theory of value engineering (VE) is the best method to coordinate improving product performance with reducing the cost of production. It realizes the improvement of the value of product and economic benefit, and achieving the purpose of optimizing the cost structure. The theory of value engineering is innovatively applied to the study of cost control of the marine diesel, the function analysis system technique graphical method (FAST) is used to analyze the function of the marine diesel to screen out 16 key components which are the research elements of Value Engineer. The comprehensivefunction proportion analysis and cost analysis method are used to analyze their value and determine the components which need to be improved. At last, this paper gives out the enforceable improving scheme.
Optimization Algorithm Study for Multiple-Constrained and Multiple-Objective Job-Shop Tool Dynamic Distribution
Authors: Wang Cui Yan , Du Wei Sheng , Wang Jun
Published: May 2014

It’s an NP problem for distributing tools for job-shop tasks when the schedules were formulated, and it belongs to multiple-constrained and multiple-objective problem. Based on adaptive weight approach, the restriction and multiple objective problems were solved. The optimization dynamic distribution model for this problem was established. Then heuristic and self-adaptive genetic algorithm was presented. In order to express the dynamic of the distribution result, Two-dimensional coding technology was adopted, a new coding rule combining dispatching rule was designed. The results show that hybrid self-adaptive genetic algorithm based on adaptive weight approach forms well for multiple-constrained and multiple-objective job-shop tool dynamic distribution.
A Study on the Intelligent Bladder Irrigation Technology
Authors: Han Liang , Fu Shi Chang , Hong Hui Hui
Published: May 2014

Bladder irrigation is one of the effective measures of prevention and control of urinary tract infection in patients with long-term indwelling catheter. Based on traditional artificial bladder irrigation technology, this paper presents a kind of intelligent bladder irrigator. The control system of this irrigator includes PLC and touch screen. The irrigator uses weighing sensor to monitor the weight of infusion bag in real time and controls pinch valve to switch the infusion tube. This paper has completed the design of the mechanical structure and control system. Intelligent bladder irrigator can realize the automation of traditional bladder irrigation.
The Application of Hybrid Recommendation Algorithm in Education Cloud
Authors: Yang Gai Zhen
Published: May 2014

When we face large amounts of data, how can we find the most suitable educational resources quickly has become a pressing issue. In this paper, on the basic of comparative study on traditional recommendation algorithms, we use the cloud computing to solve the traditional collaborative filtering algorithms suffer from scalability issues, the proposed algorithm is applied to the combination of recommended teaching cloud platform program, the program according to different recommended by demand different recommendation strategies; open source project Hadoop as a cloud development platform of the algorithm; recommendation algorithm, algorithm on top of Hadoop to achieve improved operating efficiency is relatively high, ideal parallel performance, fully proved the cloud platform and recommended algorithm combining the advantages. The research work on the recommendation system and teaching cloud computing technology applications to provide a useful reference.
Structural Non-Probabilistic Reliability Analysis Based on SAPSO-DE Hybrid Algorithm
Authors: Jong Chan Hyok , Meng Guang Wei , Li Feng , Hao Yan , Kim Kwan Gil
Published: May 2014

This paper presents a structural non-probabilistic reliability analysis approach based on a hybrid algorithm of the simulated annealing-particle swarm optimization algorithm and the differential evolution (SAPSO-DE) algorithm. In the structural non-probabilistic reliability analysis, the problem with uncertain parameters can be formulated as an optimization problem using convex model. However, the limit state function is usually implicit for the uncertain parameters. By employing the SAPSO-DE hybrid algorithm based on the evolution of the cognitive and social experiences, the problem of the structural non-probabilistic reliability analysis is solved. A numerical example is given to illustrate the high precision and good feasibility of the present method. The results shows that this proposed approach is effective, and has the predominant capability of global optimization and convergence precision.
Rectangular Paper Scraps Recovery Based on a New Edge Detection
Authors: Cao Xin
Published: May 2014

For the regular rectangular paper scraps recovery problem, at first, I used the edge detection based on the improved wavelet analysis to numerically describe the outline of words on each of the pieces. Secondly, screening according to the line spacing to find out paper scraps which are located in the edge. Thirdly, do initial matching to select the best line as a benchmark for two-dimensional double match splicing. At last, I used two-dimensional double match to make the whole stitching come out. In this paper, the data would use the 2013 China National University Mathematical Modeling Competition topic B official data. The model not only can solve the problem of this article, also can be used to solve the problem of similar cutting conditions.
Research on the Dilution Rate of Laser-Clad CBN Based on Titanium Alloy Substrate
Authors: Zhao Shu Guo , Li Rui , Yao Xiao Min
Published: May 2014

Laser cladding technique is a new surface modification technology. With the continual emergence of new materials, the improvement of surface performance has got great progress,laser cladding process has also been presented with new challenges.The dilution rate is the one of the most important process control parameters, which will affect the cladding layer quality and the surface properties. Reasonable choice of process parameters has a great impact onsurface dilution rate.This paper researches the dilution rate of laser cladding of CBN.Firstly, established the mathematical model of the dilution rate by theoretical analysis,then carried out experiments with orthogonal test method, and accurately calculated the value of the dilution rate. Obtained the effect law ofprocess parameters over dilution ratethrough visual analysis, and analyzed its reason thoroughly. Also offered some methods to reduce the dilution rate in the final part of the paper.
Numerical Analysis of Mesostructure Damage for Composite Solid Propellant Using a Combined XFEM-Cohesive Zone Model
Authors: Zhao Jiu Ling , Gao Bo , Zhao Jiu Fen
Published: May 2014

Composite solid propellant is a particulate composite with high volume fraction and wide size distribution, macroscopic mechanical behavior of SP is strongly depended on its mesostructure. This work presents a numerical analysis of mesostructure damage for SP based on XFEM and CZM method. A simplified physical model is used for the validation of the proposed method. It is shown that the result of crack extension agrees with experiment of Micro CT scan on the whole. Numerical simulations also indicate the fact that initiation of SP damage takes place at the interface of particle and matrix. At last, the relations of macroscopic strain and stress of SP with 55% volume fraction and 65% volume fraction AP are predicted based on mesostructure simulation and compared with experiments.
Theoretical Stress Concentration Factor for Spatial Helix Gear
Authors: Chen Zhen , Chen Yang Zhi , He En Yi
Published: May 2014

This paper presents a method to calculate the theoretical stress concentration factor of spatial helix gears, combined with the numerical method by ANSYS FEA package and analytic method. The formula of theoretical stress concentration factor of driving tine is fitted numerically, which suits for the general application situation. Effects of the main parameters on theoretical stress concentration factor are analyzed respectively.
Cytocompatibility of Magnesium-Zinc-Calcium Alloys with Bone Marrow Derived Mesenchymal Stem Cells
Authors: Cipriano Aaron F. , Miller Christopher , Liu Hui Nan
Published: May 2014

Magnesium (Mg)-based alloys have attracted great interest as metallic biomaterials for orthopedic applications due to their biocompatibility, biodegradability, and mechanical properties that resemble those of cortical bone. However, the potential toxicity of alloying elements in commercially available Mg alloys makes it critical to engineer and screen new alloys specifically for biomedical applications. The objective of this study was to evaluate and compare the in vitrodegradation and cytocompatibility of two distinct Mg - Zinc (Zn) - Calcium (Ca) alloys (Mg-4%Zn-1%Ca and Mg-9%Zn-1%Ca, wt. %; abbreviated as ZCa41 and ZCa91, respectively) using a bonemarrow derived mesenchymal stem cell (BMSC) model. Both Zn and Ca play critical roles in boneformation and growth, and have been shown to increase mechanical and corrosion properties of Mgalloys. BMSCs provide vertebrates the continuous supply of osteoblasts needed for bone remodelingand repair, and thus were selected to determine the effect of increasing Zn content on cell behavior.Surface microstructure and composition of the alloys were characterized before and after BMSC culture using field emission scanning electron microscopy (FESEM) and energy dispersive X-rayspectroscopy (EDS). Thermanox® treated glass and plasma treated tissue culture polystyrene were used as a control and reference, respectively. Results indicated that the ZCa91 alloy improved BMSC adhesion as compared with ZCa41 alloy. The formation of high-aspect ratio needle-likefeatures on the surface of ZCa41 alloy after its degradation in cell culture media was speculated tocontribute to the lower cell adhesion. This study provided an early indication on cytocompatibility of Mg-Zn-Ca alloys for biomedical applications.
Evaluation of the Effect of TiC Precipitates on the Hydrogen Trapping Capacity of Fe-C-Ti Alloys
Authors: Depover Tom , van den Eeckhout E. , Wallaert E. , Zermout Z. , Verbeken Kim
Published: May 2014

The present work evaluates the hydrogen trapping behavior of different laboratory cast generic Fe-C-Ti martensitic alloys. Titanium carbides were precipitated in the materials by well-designed heat treatments. A quenched and tempered martensitic matrix with final strength above 1000 MPa was aimed for and verified by means of hardness measurements. Tempering allowed generating precipitates with different characteristics in terms of coherency, size and distribution due to the secondary hardening effect, as was evaluated by transmission electron microscopy. The hydrogen trapping capacity of the TiC precipitates was investigated by thermal desorption spectroscopy, while melt extraction was performed to determine the amount of hydrogen present after cathodic hydrogen charging. Generally, it could be concluded that the incoherent particles in the quenched material were not able to trap hydrogen, whereas the quenched and tempered material trapped hydrogen at the interface of small probably coherent TiC.
Study of the Influence of Plastic Deformation on Metastable Phases of CuAlBe Shape Memory Alloy by Neutron Diffraction
Authors: Dubois Matthieu , Mathon Marie Hélène , Klosek Vincent , Benmarouane A. , Lodini Alain
Published: May 2014

This work aims to study by neutron diffraction the evolution of metastable phases of CuAlBe shape memory alloy after plastic deformation. Two samples were studied: the first one deformed by cold rolling at a reduction rate of 15% and the second, deformed by cold rolling at 15% followed by hot rolling at 200°C for a reduction rate of 30% respectively.
Before plastic deformation, the material is fully austenitic at ambient temperature. Its crystallographic texture is mainly characterized by a <001> partial fibber. After deformation, this partial fibber disappears and the crystallographic texture is composed by isolated orientations. At higher reduction rates, the texture of austenitic phase remaining in the material is characterized by a <111> fibber.
The rolling process modifies metastable phase quantities. After deformation at a reduction rate of 15%, the volume fraction of metastable austenite remaining is close to 8%. Plastic deformation also greatly modifies the characteristic transformation temperatures and enlarges the hysteresis. The material plastically deformed after hot rolling presents large variations of intensities of diffraction peaks belonging to martensite phase during a thermal cycle at low temperature. This effect is attributed to a reorganization of variants due to an evolution of crystallographic texture of martensite.
Embrittlement of Steels by Liquid Zinc: Crack Propagation after Grain Boundary Wetting
Authors: Frappier Renaud , Paillard Pascal , Le Gall René , Dupuy Thomas
Published: May 2014

This study characterizes the mechanical behavior of an advanced multiphase high strength steel by means of high temperature tensile testing. The results show a drastic reduction of the maximum tensile elongation from around 700 °C up to 950°C. Scanning electron microscopy investigations show that the temperature range for embrittlement is correlated with the total wetting of steel grain boundaries. Under external strain, crack propagates along the grain boundaries according to a mechanism that leads to the presence of nanometer-thick films of Zn at the crack tip, as shown by fine X-ray spectroscopy analyses. The effective temperature range for embrittlement is discussed. Mechanisms of i) external stress-free wetting, and ii) atomic-scale crack propagation, are today under discussion in the light of the literature, regarding in particular recent experimental results and theory about grain boundary wetting, intergranular penetration, and the correlation between surface energy and crack propagation rate.
Monitoring of Tempering Behavior in Fe-C-Mn Alloys by Precise Measurement of Electrical Resistivity
Authors: Fujita Kosuke , Ueda Masato , Ikeda Masahiko , Hayashi Kotaro
Published: May 2014

Mechanical properties in metallic materials are generally determined by microstructure, which is controlled by thermo-mechanical treatment in addition to its composition. Tempering is the conventional process of heat-treated steel. Therefore, understanding microstructural change during the process is especially important. As is well known, electrical resistivity measurement gives useful information regarding microstructures and lattice defects. In this technique, average information can be obtained from larger volume of specimens than TEM specimens as 108 times. So the purpose of this study was to monitor electrical resistivity changes related to microstructural changes during tempering in Fe-0.19 C-1.5 Mn, Fe-0.35 C-1.5 Mn alloys. Bar shaped specimens were cut from the sheets of steels. The specimens were heat-treated in austenite region and then quenched with ice-water. Then tempering was cumulatively carried out by direct dipping in a nitrate bath held at 423-673 K. Electrical resistivities at 77 K (in liquid nitrogen) and 300 K were measured in each state by a direct current (DC) four-point method. The resistivities abruptly decreased and then gradually decreased by the tempering. First drop and following decreasing of resistivities are corresponding to vanishing vacancies in martensite and precipitation of carbide, respectively. The organized resistivites by Hollomon-Jaffe parameter showed infections during the carbide precipitation. The points must be related to transition of precipitation mode.
Effect of Carbon Gradient on the Microstructure and Mechanical Properties of Fe-22Mn-C TWIP/TRIP Steels
Authors: Ghasri-Khouzani Morteza , Bruhis M. , McDermid Joseph Robert
Published: May 2014

High-manganese austenitic steels are promising emerging automotive steels demonstrating high strength and ductility. The main deformation products observed in these steels are mechanical twins and ε-martensite, where the dominant deformation products vary quite strongly with stacking fault energy (SFE), which in turn is a very strong function of the alloy carbon content. In this research, a Fe-22Mn-0.6C sheet steel was decarburized to achieve a variety of through-thickness C gradients, thereby varying the dominant deformation products through the sheet thickness, with the overall objective of producing unique microstructures and mechanical properties. Microstructural analyses after interrupted tensile testing indicated that the amount of both mechanical twins and ε-martensite increased with increasing true strain, where the deformation products changed from mechanical twins at the higher-C core to ε-martensite at the lower-C surface. The spring-back properties of the C graded steels were also compared with reference to the effect of differential carbon concentration gradient.
Cu/Cu Direct Bonding by Metal Salt Generation Bonding Technique with Formic Acid and Citric Acid
Authors: Hagiwara Naoki , Koyama Shinji , Shohji Ikuo
Published: May 2014

The effect of formic acid and citric acid surface modification on the bonded strength of the solid-state direct bonded interface of copper was investigated by SEM observations of interfacial microstructures and fractured surfaces. Copper surfaces were modified by boiling in 98% formic acid for 0.6 ks and 17% aqueous solution of citric acid for 0.96 s. Solid-state bonding was performed in a vacuum chamber at bonding temperature of 423 ~ 673 K under a pressure of 588 N (bonding time of 0.9 ks). As a result of surface modification by formic acid and citric acid, bonded joints were obtained at a bonding temperature 150 K (formic acid) and 100 K (citric acid) lower than that required for non-modified surfaces, and the bond strength was comparable to that of the maximum load.
Preparatory Electrodeposition Process for High Purity Bulk Aluminum
Authors: Hanaoka Yudai , Ono Satoshi , Matsui Isao , Takigawa Yorinobu , Uesugi Tokuteru , Higashi Kenji
Published: May 2014

Electrodeposition for Al from a dimethylsulfone (DMSO2) bath was consecutively performed, applying two types of current waveforms such as direct current and pulsed current, to investigate the effect of a current type on the preparatory electrodeposition (pre-electrodeposition) process. Electrodeposited Al from a DMSO2 bath has a nanograined structure and high strength. However, the electrodeposits showed no plastic deformability due to the large amount of sulfur and chlorine which were incorporated into the electrodeposits as sulfide and chloride. Therefore, we obtained high purity Al from a DMSO2 bath using pre-electrodeposition process, which could decrease sulfur and chlorine contents without using additives. The sulfur and chlorine contents of electrodeposits, obtained from a DMSO2 bath applying both types current, both decreased to approximately 0.1 at.%. This result indicated that the waveforms made no difference in pre-electrodeposition process.
Microstructure of Oxide Scale on Hot-Rolled Iron
Authors: Hara Kenichiro , Utsunomiya Hiroshi , Matsumoto Ryo
Published: May 2014

In hot rolling processes, oxide scale shows complicated deformation behavior and may cause surface defects on sheet. It influences the friction and the heat transfer on the interface between the sheet and the rolls. To reveal the mechanism, it is necessary to investigate the scale deformation during the hot rolling. In this study, the microstructure of the scale before / after the hot rolling was preserved by glass coating and analysed by scanning electron microscopy (SEM)/ electron backscatter diffraction (EBSD) technique. Using this technique, the microscopic deformation of oxide scale during hot rolling is discussed. Electrolytic pure iron sheets were rolled at a thickness reduction of 30% at 1273 K after oxidation in air for 0 s to 40 s. The scale consists of columnar grains which cover mostly throughout the thickness. The scale preferentially grows to the thickness direction at the initial stage of oxidation (<10 s). After the initial stage (>10 s), scale grains grow parallel as well as perpendicular in the thickness direction (ND). The scale grains are deformed at a fixed volume during hot rolling. The lower ductility of the thick scale results in the fracture of the scale and extrusion of matrix sheet to the outermost surface.
X-Ray Residual Stress Analysis of Nickel Base Alloys
Authors: Sasaki Toshihiko , Miyazaki Toshiyuki , Ito Hamiru , Furukawa Takashi , Mihara Tsuyoshi
Published: May 2014

Nickel based alloys are widely used in steam generator tubes for nuclear power plants. 1-D X-ray stress measurements have been used for these alloys. But 1-D method requires large equipment and it is practically impossible to measure stress in power plants. In order to overcome this problem, we adopted 2-D X-ray method which requires significantly smaller equipment. In this paper we report preliminary results of 2-D X-ray stress measurements of nickel based alloys.
Feasibility Study on Die Quenching of AA2024 Aluminum Alloy Billet Using Servo Press
Authors: Jeon Jae Yeol , Matsumoto Ryo , Utsunomiya Hiroshi
Published: May 2014

Die quenching of an AA2024 aluminum alloy billet was carried out using a servo press with ram motion control of WC-20mass%Co dies directly after solution heat treatment (SHT). The cylindrical billets were heated in an electric furnace and transferred to the press, then subjected to uniaxial compression with a reduction in height (Δh/h0) of 2%, 5% or 10% after SHT at 773 K or 823 K. The die quenching was successfully carried out without the precipitation hardening only on the billet after SHT at 823 K by sandwiching for 8 s. The subsequent artificial aging behavior at 463 K in an oil bath was investigated. It is found that the precipitation kinetics is accelerated in the die-quenched billets after SHT at 823 K. The peak hardness of the billet processed with 5% after SHT at 823 K is as high as that of the water-quenched billet, HV 149.0.
Effect of Retained Austenite on Impact Toughness of the Multi-Phase Bainitic-Martensitic Steel
Authors: da Cruz José Alberto , Vilela Jefferson José , Gonzalez Berenice Mendonça , Santos Dagoberto Brandão
Published: May 2014

The new class of bainitic steels can present toughness at room temperature greater than traditional quenched and tempered martensitic steel. This is because the microstructure of steel with high Si content (≈1.5wt%) submitted to bainitic transformation is compose of fine plates of bainitic ferrite separated by retained austenite. The inhibition of cementite precipitation leads to the improvement of toughness. The presence of cementite facilitates the nucleation of cracks. Moreover, the blocks of retained austenite are undesirable. This morphology is rather unstable and tends to transform into hard and brittle untempered martensite under the influence of small stress, contributing to a low toughness. However, it was observed in this work that the greater the volume fraction of retained austenite, the greater is the toughness (10-24 J) for multi-phase steel. The values of toughness were independent whether the retained austenite is present on film or block forms. The decrease of toughness values was observed by the tempered samples after the bainitic transformation (10-14 J). This occurred because the blocks of retained austenite decomposed into carbides, martensite and/or bainite.
Effects of Ni and Co Additions to Filler Metals on Ag-Brazed Joints of Cemented Carbide and Martensitic Stainless Steel
Authors: Kaiwa Kengo , Yaoita Shinji , Sasaki Tomohiro , Watanabe Takehiko
Published: May 2014

This study focuses on understanding the effect of Ni and Co additions to filler metals on Ag-brazed joints of cemented carbide and martensitic stainless steel. Ni and Co added braze alloys were processed based on Ag-Cu-Zn ternary alloy, and joint strength and microstructure of the brazed layer has been investigated. The joint strength increased by the 2.0mass%Ni and 0.5mass%Co addition into braze alloy. This trend is remarkable in the Co added alloy, and the brazed joint increased by 141% compared to that in no-added alloy. The joint strength was closely related to the suppression effect of Co dissolution from cemented carbide into filler layer and Fe diffusion from the stainless steel to the brazed layer. In the brazed microstructure, Co-depleted zone caused by dissolution of Co in the cemented carbide was observed near the interface between the cemented carbide and the steel. Width of the Co-depleted zone significantly decreased in the Co added alloy. However, the joint strength decreased in the multiple addition compared to that in the single addition of Ni or Co.