bluuebunny/crossref_metadata_2025 huggingface dataset:
Developing an Online Synthetic Validation Tool
Authors: McCloy Rodney A. , Putka Dan J. , Gibby Robert E.
Published: August 2010

In their comprehensive apologetic treatment of synthetic validity, Johnson et al. (2010) echo Hough (2001), advocating development of a central synthetic validation database, which would serve as a repository of validity information to support future synthetic validation efforts. They offer two potential approaches for developing such a database. The first entails the conduct of “a large-scale study in which tests are administered to and performance ratings gathered on incumbents in a large number of jobs in a variety of organizations.” The authors consider this approach to be “ideal but impractical,” largely because of the scope and cost of the data collection required and the resulting investment required by any sponsoring organization. The second entails the conduct of multiple local studies to generate empirical estimates of relationships between measures of various predictor constructs and a standardized set of job components. Johnson et al. consider this approach more practical, citing Meyer, Dalal, and Bonaccio (2009) as a benchmark example.
At Sea With Synthetic Validity
Authors: Steel Piers , Johnson Jeff W. , Jeanneret P. Richard , Scherbaum Charles A. , Hoffman Calvin C. , Foster Jeff
Published: August 2010

We expected that the commentary process would provide valuable feedback to improve our ideas and identify potential obstacles, and we were not disappointed. The commentaries were generally in agreement that synthetic validity is a good idea, although we also received a fair amount of suggestions for improvements, conditional or tempered praise, and explicitly critical comments. We address the concerns that were raised and conclude that we should move forward with developing a large-scale synthetic validity database, incorporating the suggestions of some of the commentators.
A Satake isomorphism in characteristic p
Authors: Herzig Florian
Published: August 2010

Suppose that G is a connected reductive group over a p-adic field F, that K is a hyperspecial maximal compact subgroup of G(F), and that V is an irreducible representation of K over the algebraic closure of the residue field of F. We establish an analogue of the Satake isomorphism for the Hecke algebra of compactly supported,K-biequivariant functions f:G(F)→End   V. These Hecke algebras were first considered by Barthel and Livné for GL 2. They play a role in the recent mod p andp-adic Langlands correspondences for GL 2 (ℚp) , in generalisations of Serre’s conjecture on the modularity of mod p Galois representations, and in the classification of irreducible mod p representations of unramified p-adic reductive groups.
EFFECTS OF CONFIDENCE SCALE AND NETWORK STRUCTURE ON MINORITY OPINION SPREADING
Authors: SHEN BO , LIU YUN
Published: August 2010

We study the dynamics of minority opinion spreading using a proposed simple model, in which the exchange of views between agents is determined by a quantity named confidence scale. To understand what will promote the success of minority, two types of networks, random network and scale-free network are considered in opinion formation. We demonstrate that the heterogeneity of networks is advantageous to the minority and exchanging views between more agents will reduce the opportunity of minority's success. Further, enlarging the degree that agents trust each other, i.e. confidence scale, can increase the probability that opinions of the minority could be accepted by the majority. We also show that the minority in scale-free networks are more sensitive to the change of confidence scale than that in random networks.
EFFECTS OF HETEROGENEOUS INFLUENCE OF INDIVIDUALS ON THE GLOBAL CONSENSUS
Authors: LIN YING-TING , YANG HAN-XIN , RONG ZHI-HAI , WANG BING-HONG
Published: August 2010

We propose an opinion dynamics model to study the effects of heterogeneous influence of individuals on the global consensus. Each individual is assigned a weight that is proportional to the power of its degree, where the power exponent α is an adjustable parameter. Interestingly, it is found that there exists an optimal value of α leading to the shortest consensus time for scale-free networks, random networks and small-world networks. Other quantities, such as the probability that an individual's initial opinion becomes the final opinion as a function of degree, the evolution of the number of opinion clusters, as well as the relationship between average consensus time and the network size, are also studied. Our results are helpful for understanding the role of heterogeneous influence in the opinion dynamics.
EMERGENCE OF POWER-LAW IN SPATIAL EPIDEMICS USING CELLULAR AUTOMATION
Authors: LI LI , SUN GUI-QUAN , JIN ZHEN
Published: August 2010

We analyze a spatial susceptible-infected epidemic model using cellular automata and investigate the relations between the power-law distribution of patch sizes and the regime of invasion. The obtained results show that, when the invasion is in the form of coexistence of stable target and spiral wave, power-law will emerge, which may provide a new insight into the control of disease.
APPLICATION OF ABEL–PLANA FORMULA FOR COLLAPSE AND REVIVAL OF RABI OSCILLATIONS IN JAYNES–CUMMINGS MODEL
Authors: AZUMA HIROO
Published: August 2010

In this paper, we give an analytical treatment to study the behavior of the collapse and the revival of the Rabi oscillations in the Jaynes–Cummings model (JCM). The JCM is an exactly soluble quantum mechanical model, which describes the interaction between a two-level atom and a single cavity mode of the electromagnetic field. If we prepare the atom in the ground state and the cavity mode in a coherent state initially, the JCM causes the collapse and the revival of the Rabi oscillations many times in a complicated pattern in its time-evolution. In this phenomenon, the atomic population inversion is described with an intractable infinite series. (When the electromagnetic field is resonant with the atom, the nth term of this infinite series is given by a trigonometric function for [Formula: see text], where t is a variable of the time.) According to Klimov and Chumakov's method, using the Abel–Plana formula, we rewrite this infinite series as a sum of two integrals. We examine the physical meanings of these two integrals and find that the first one represents the initial collapse (the semi-classical limit) and the second one represents the revival (the quantum correction) in the JCM. Furthermore, we evaluate the first- and second-order perturbations for the time-evolution of the JCM with an initial thermal coherent state for the cavity mode at low temperature, and write down their correction terms as sums of integrals by making use of the Abel–Plana formula.
MONITORING THE TOPOLOGY OF GROWING DYNAMICAL NETWORKS
Authors: WU ZHAOYAN , FU XINCHU , CHEN GUANRONG
Published: August 2010

In this paper, topology monitoring of growing networks is studied. When some new nodes are added into a network, the topology of the network is changed, which needs to be monitored in many applications. Some auxiliary systems (network monitors) are designed to achieve this goal. Both linear feedback control and adaptive strategy are applied to designing such network monitors. Based on the Lyapunov function method via constructing a potential or energy function decreasing along any solution of the system, and the LaSalle's invariance principle, which is a generalization of the Lyapunov function method, some sufficient conditions for achieving topology monitoring are obtained. Illustrative examples are provided to demonstrate the effectiveness of the new method.
GRAIN BOUNDARY WETTING AND SOLIDIFICATION OF CONSTITUTIONAL LIQUID IN AZ91 MG CAST ALLOY
Authors: ZHU TIANPING , CHEN ZHAN W. , GAO WEI
Published: August 2010

In this study, constitutional liquation in AZ91 cast alloy at 440°C and 465°C was experimentally simulated. Metallurgical examination was conducted to reveal the morphology of the constitutional liquid and dihedral angle was measured to evaluate the wettability of the liquid on grain boundary. Dihedral angle was found to be initially ~30 degree and thus grain boundaries were incomplete wet. During annealing, the metastable constitutional liquid resolidified, followed by grain growth. The extent of grain boundary wetting by the remaining liquid increased slightly with treating time. The rate of resolidification was also evaluated and the factors affecting this rate were discussed.
THE INVESTIGATION ON LAMELLAR MICROSTRUCTURE TRANSFORMATION AND STABILITY IN TIAL BASED INTERMATELLICS
Authors: ZHANG WEI , MA YUE , GONG SHENGKAI
Published: August 2010

Microstructure stability in fully lamellar (FL) structure TiAl based intermatellics have been studied. The experiment results have shown that the smaller the lamellar spacing is, the more instable the lamellar structure is. The distinct lamellar spheroidization occurs at 1150°C holding for 24h. This phenomena may be caused by lamellar coarsening and decomposition. The linear residual β phase distributed in the Ti -47 A 1-2 Cr -2 Nb alloy may prevent lamellar spheroidization and improves the stability of lamellar structure significantly.
IMPROVED MECHANICAL PROPERTY OF ELECTRODEPOSITED NANOCRYSTALLINE NICKEL-COBALT ALLOY
Authors: SHEN XIXUN , LIAN JIANSHE
Published: August 2010

A bulk and dense nc Ni -24.7% Co with an average grain size of 15nm was fabricated by a direct current electrodeposition. This Ni -24.7% Co exhibits very high tensile strength of 1813MPa to 2232MPa with relatively good tensile ductility of 6.0%~9.6% under tensile test over a wide strain rate range of 0.417s-1 ~ 1.35×10-5s-1. The combination of high strength and good ductility should be attributed to the increased strain hardening ability induced by the addition of alloying Co element. The interaction of dislocation and grain boundaries is the rate-controlling deformation mechanism controlled in the Ni -24.7% Co based on its high strain rate sensitivity of 0.029 and small activity volume of ~14b3.
SYNTHESES AND PROPERTIES OF COBALT AND NICKEL HYDROXIDE NANOSHEETS
Authors: KURASHINA MASASHI , EGUCHI AKIO , KANEZAKI EIJI , SHIGA TAKUYA , OSHIO HIROKI
Published: August 2010

Nanosheets of cobalt and nickel hydroxides nanosheets were prepared by delamination of layered compounds, Co II( OH )1.73( DBS )0.27·0.87 H 2 O ( Co - DBS , DBS = dodecylbenzene sulfonate) and Ni II( OH )1.63( DBS )0.37·1.24 H 2 O ( Ni - DBS ), respectively. Powder X-ray diffraction analyses of the layered compounds revealed lattice parameters of a0 = 3.07 Å and c0 = 30 Å ( Co - DBS ) and a0 = 3.09 Å and c0 = 30 Å ( Ni - DBS ) in the hexagonal system. Dispersions of Co - DBS and Ni - DBS in 1-butanol produced colloidal solutions of nanosheets, [ Co - DBS ] delam and [ Ni - DBS ] delam , respectively. Poly(vinylpyrrolidone) ( PVP ) was dissolved in [ Co - DBS ] delam and [ Ni - DBS ] delam and the mixtures were dried to yield Co - PVP and Ni - PVP , respectively. These nanosheets measured 150-500 nm for [ Co - DBS ] delam and 135-400 nm for [ Ni - DBS ] delam by means of dynamic light scattering. Atomic force microscopy images showed lateral dimensions of 100-500 nm for [ Co - DBS ] delam and 50-100 nm for [ Ni - DBS ] delam . In the former image, the cobalt hydroxide nanosheets had a fairly flat terrace structure with thickness of 3.1-3.6 nm and with aspect ratios of 30-150, whereas in the latter image dome-like nanosheets of nickel hydroxide with height of 2.2-2.3 nm were confirmed. These nanosheets were regarded as monolayer. Magnetization experiments at 1.8 K showed hysteresis loops for Co - DBS , Co - PVP , Ni - DBS , and Ni - PVP .
MAGNETIC PROPERTIES OF FENI NANOWIRE ARRAYS ASSEMBLED ON POROUS AAO TEMPLATE BY AC ELECTRODEPOSITION
Authors: WANG PANGPANG , GAO LUMEI , WANG LIQUN , ZHANG DONGYAN , YANG SEN , SONG XIAOPING , QIU ZHIYONG , MURAKAMI RI-ICHI
Published: August 2010

FeNi nanowire arrays were fabricated into the pores of porous alumina template by a simple alternating current electrodeposition method in this work. FeNi nanowires with different diameters were obtained depending on the pore size arrangement of alumina templates. FeNi nanowire arrays exhibited obviously magnetic anisotropy, and the easy axis was along the nanowires. When the applied magnetic field was parallel to the nanowires, the coercivity (Hc) and the maximum remnant ratio (Mr/Ms) are considerable higher than those while the magnetic field perpendicular to the nanowires. FeNi nanowires prepared in this work are expected to be utilized as the perpendicular magnetic recording media. The magnetic domain structure and the magnetizing mechanism of FeNi nanowires were also been discussed.
EFFECT OF STRUCTURAL RELAXATION ON THE DEFORMATION BEHAVIOR OF A Zr64.13Cu15.75Ni10.12Al10 BULK METALLIC GLASS UNDER NANOINDENTATION
Authors: GU JIANSHENG , WEI BINGCHEN , ZHANG TAIHUA , FENG YIHUI , HU YANPING , SUN ZHIWEI
Published: August 2010

Structural relaxation by isothermal annealing below the glass transition temperature is conducted on a Zr 64.13 Cu 15.75 Ni 10.12 Al 10 bulk metallic glass. The effect of structural relaxation on thermal and mechanical properties was investigated by differential scanning calorimetry and instrumented nanoindentation. The recovery of the enthalpy in the DSC curves indicates that thermally unstable defects were annihilated through structural relaxation. During nanoindentation, the structural relaxation did not have a significant influence on the serrated plastic flow behavior. However, Structural relaxation shows an obvious effect in increasing both the hardness and elastic modulus, which is attributed to the annihilation of thermally unstable defects that resulted from the relaxation.
MONITORING OF FAILURE MECHANISMS IN A COMPOSITE BENDING ACTUATOR DURING CYCLIC LOADING BY ACOUSTIC EMISSION
Authors: WOO SUNG-CHOONG , GOO NAM SEO
Published: August 2010

The objective of this work is to investigate the influence of electromechanical cyclic loading on the performance of a bending piezoelectric composite actuator. We have analyzed the fatigue damage mechanisms in terms of the behavior of the AE event rate. It was found that whether the actuators are subjected to purely electric loading or electromechanical loading, the initial fatigue damage of the bending piezoelectric composite actuator was caused by the transgranular fracture in the PZT ceramic layer; the final failure was caused only in the case of PCAWB under electromechanical loading by a local discharge, which critically affected the performance reduction of the actuators. As the number of cycles increased, a large reduction in displacement performance coincided with a high AE event rate, which was identified via microscopic observations.
FIRST PRINCIPLE STUDY ON THE EFFECT OF Fe CONTENT ON THE PHASE STABILITY OF THE Ni-Mn-Ga ALLOY
Authors: GAO ZHIYONG , TAN CHANGLONG , DONG GUIFU , SUI JIEHE , CAI WEI
Published: August 2010

The effect of Fe elements on the total energy of Ni 2 MnGa ferromagnetic shape memory alloy was investigated. It is shown that Fe addition has little effect on the majority-spin density of state (DOS), but changes minority-spin DOS significantly. Substituting Fe for Mn decreases the total DOS of the parent phase, leading to the increase in parent phase stability. When Fe content is higher than 12.5at%, the increasing of martensitic transformation is related to the precipitation of γ phase.
MODEL AND EXPERIMENTAL STUDY OF GIANT MAGNETOSTRICTIVE POWER GENERATION
Authors: WANG Z. H. , WANG B. W. , YI Y. F. , WANG M. W. , WANG Y. B. , WENG L.
Published: August 2010

A mathematical model of vibration power generation (VPG) with the giant magnetostrictive material (GMM) is proposed on the basis of the magneto-mechanical coupling model, Jiles-Atherton model and electromagnetic induction law. According to the model, the output voltage of a giant magnetostrictive power generator has been calculated under the condition of different vibration frequency, pre-stress and bias magnetic field. The calculating results show that the model can reveal the relationship between the input vibrating stress and output voltage. The experiment of a giant magnetostrictive power generator has been carried out, and the experimental results agree well with the calculating results.
A MINIATURE HIGH-SPEED PIEZOELECTIRC MOTOR WITH A DISK-PIVOT STRUCTURE
Authors: CHU XIANGCHENG , CHEN XIANGYU , MA LONG , LI LONGTU
Published: August 2010

A miniature disk-pivot piezoelectric motor using a vibration mode B 11 of one nodal circle and one nodal diameter was investigated. Different from conventional wobble-type piezoelectric motor using piezoelectric rod or cylinder, a metal/piezoelectric disk is used to simulate the wobble vibration and an embedded metal cylinder is used to amplify the transverse displacement to obtain a much higher revolution speed over 10,000 rpm through the contact friction between the stator and rotor. The outer diameter of the metal/piezoelectric disk and the embedded cylinder is 14 mm and 2.5 mm, respectively. In order to avoid the coupling between the B 11 and any other vibration modes, the structure of the stator is analyzed using Finite Element Method (FEM) and optimized to avoid the influence between them. The simulations show that the stability of the disk-pivot piezoelectric motor will be influenced greatly when any other vibration mode is close to the mode B 11. To separate the coupling modes, two structure parameters can be modified: the thickness of the piezoelectric ceramic and the height of the middle metal cylinder on the stator. And these methods were proved through testing some prototypes of the motors.
A NOVEL PIEZOELECTRIC DEVICE
Authors: YUAN SONG-MEI , TANG ZHUANG-YUN
Published: August 2010

This paper introduces a new based-on ultrasonic wave micro-fluid driving technique that is different from the present principle. The standing wave is generated by ultrasonic vibration in the device, and acoustic field is generated simultaneously. The particles in fluid medium of the device move towards the node of the standing waves caused by the effect of acoustic radiation pressure. A new device structure has been designed based on piezoelectric drive principle. The vibration modes and response has been obtained by FEA. The simulation results also indicate the feasibility of movements. Considering the influence of vibrator dimension, the dimension of the vibrator has been optimized. The experiment has been accomplished in the device with polystyrene spheres and achieves the enrichment of the particles.
PHASE TRANSFORMATIONS AND MECHANICAL PROPERTIES OF NITIAL SHAPE MEMORY ALLOYS WITH EQUAL NI/TI ATOM RATIO
Authors: LI YAN , LIU ZEMIN , XIAO LI
Published: August 2010

Phase transformation, microstructure and mechanical property of Ni 50- x /2 Ti 50- x /2 Al x ( x =1, 2, 3 and 4 at.%) alloys have been investigated by electrical resistance (ER) measurement, scanning electron microscope (SEM), X ray diffraction (XRD) and tensile tests. The results show that a two-step phase transformation occurs from parent phase to R phase and subsequently to martensite upon cooling, and the transformation reverses upon heating. Both the martensitic transformation and R phase transformation temperatures decrease with increasing of Al content. The microstructure analysis indicates that the NiTi - Al alloys are composed of NiTi as the predominant phase and Ti 2 Ni as the second phase mainly distributing at grain boundaries. The solid solution hardening effect of Al at room temperature has been demonstrated by the remarkable increasing of yielding strength and decreasing of tensile strain with increasing of Al content. Ni 49 Ti 49 Al 2 alloy deformed at the liquid temperature exhibits a maximum recoverable strain of 6.3%.
OPTIMUM DESIGN OF CANTILEVERED MICROPROBES FOR INSPECTING LCD PANELS AND MEASUREMENT OF CONTACTING FORCES
Authors: KIM CHEOL , KIM KWANG-JOONG
Published: August 2010

Fine pitch microprobe arrays are microneedle-like probes for inspecting the pixels of LCD panels or IC. They are usually made of multi-layers of metallic, nonmetallic, or combination of the two. The design requirement for a contacting force is less than 2 gf and a deflection should be less than 100 µm. Many microprobe shapes satisfying the design requirements are possible. A cantilever-type microprobe having many needles was chosen and optimized in this study. Several candidate shapes were chosen using topology and shape optimization technique subjected to design requirements. Then, the microprobe arrays were fabricated using the process applied for MEMS fabrication and they were made of BeNi , BeCu , or Si . The contact probing forces and deflections were measured for checking the results from optimum design by newly developed measuring equipment in our laboratory. Numerical and experimental results were compared and both showed a good correlation.
A STUDY ON THE ALTERNATIVE TECHNOLOGY USING UNSM INSTEAD OF THE PRESETTING METHOD FOR TORSION BAR
Authors: SUH CHANG-MIN , KIM MIN-HO , BAEK UN-BONG , PYOUN YOUNG-SIK , KIM CHANG-SIK , CHI CHONG-HO
Published: August 2010

The torsion bar must be changed periodically due to its lack of durability and a phenomenon related to stress relaxation. Therefore technical development regarding the torsion bar's durability is urgently needed. In order to improve the fatigue life and durability of the dynamic components, new surface treatment technology such as ultrasonic shot peening, deep rolling, laser shock peening, etc. are developing widely. In this study, Ultrasonic Nanocrystal Surface Modification (UNSM) technology is applied as an advanced one to replace the presetting method (PM). UNSM and PM technology also induced the compressive residual stress on the surface layer of the torsion bar, which is the main improvement factor of fatigue life. DIN17221 material as a new MIL specification of torsion bar and SCM440 (as an alternative one to a old MIL-DTL-62567C) were processed with the UNSM technology to obtain the basic data and compare it between two, and then torsion fatigue tests of two materials were carried out to obtain the characteristics of torsion fatigue in this study.
STRESS-STRAIN RELATIONSHIP OFZR55AL10NI5CU30METALLIC GLASS ANALYZED BY 3D IMAGES ON SPHERICAL INDENTS
Authors: LEE YUN-HEE , PARK JONG SEO , LEE HAE MOO , NAHM SEUNG HOON
Published: August 2010

Mechanically polished surface of Zr55Al10Ni5Cu30metallic glass was indented with a rigid ball 0.5 mm in diameter and its corresponding load-depth curve was recorded automatically. Although a stress-strain relationship beneath the indenter can be analyzed from the raw indentation curve, the current analysis developed for crystalline solids can mislead erroneous properties because it does not consider significant material pile-ups in amorphous metallic glasses. Thus, we proposed a novel indent image processing technique for characterizing the contact and flow properties in the metallic glasses; the contact area was measured by differentiating a three-dimensional indent morphology digitized by a surface profiler and a surface-stretching strain was newly defined in order to estimate the flow properties. Finally, the work-hardening index estimated was about 0.05, comparable with the typical value measured from uniaxial compression in the Zr -based metallic glass.
INNOVATIVE MANUFACTURING OF CARBON NANOTUBE-LOADED FIBRILLAR POLYMER COMPOSITES
Authors: LIN R. J. T. , BHATTACHARYYA D. , FAKIROV S.
Published: August 2010

The concept of microfibrillar composite (MFC) has been used to create a new type of polymer composites, in which the reinforcing microfibrils are loaded with carbon nanotubes (CNT). Polyamide 66 (PA66) has been melt blended with polypropylene in a twin screw extruder with and without CNT, and thereafter cold drawn to create a fibrillar state as well as to align the CNT in the PA66 microfibrils. The drawn bristles were compression moulded at 180°C to prepare MFC plates. The scanning electron microscope (SEM) observations indicate near perfect distribution of CNT in the reinforcing PA66 microfibrils. Although the fibrillated PA66 is able to improve the tensile stiffness and strength as expected from the MFC structure, the incorporation of CNT does not exhibit any further enhancing effect. It rather adversely affects the mechanical properties due to poor interface adhesion between the matrix and the reinforcing microfibrils with the presence of CNT, as demonstrated by SEM. However, the resulting highly aligned CNT within the MFC are expected to affect the physical and functional properties of these composites.
CONSTRUCTION PLACEMENT AND HARDENED PROPERTIES OF SHOTCRETE WITH HIGHLY FUNCTIONAL FLY ASH
Authors: YUNO KUNIHIRO , ISHII MITSUHIRO , HASHIMOTO CHIKANORI , MIZUGUCHI HIROYUKI
Published: August 2010

Shikoku Electric Power Co., Inc. has developed the technology to manufacture a brand name "Finash" about 12 years ago, by sorting and classifying coal ash generated in coal fired power plants. "Finash" is highly functional fly ash (HFA) is produced by removing irregular coarse particles. It is important for the production of HFA to minimize the variation in quality of coal ash with sophisticated classification technique and extracting good-quality spherical fine particles. It is now widely utilized as concrete admixture for general civil engineering structures and buildings in Japan. When highly functional fly ash (HFA) is used as shotcrete admixture to substitute for fine aggregate of 100kg/m3, the shotcrete has the advantages of decreasing the amount of dust and rebound during spraying operation, improving the hardened properties of concrete, etc. Therefore, it has been applied in many tunnel construction projects. This paper discusses about the various characteristics such as construction placement, strength, neutralization and dry shrinkage of shotcrete using highly functional fly ash (HFA), using the results that is obtained from spray test in an actual road tunnel.
EFFECT OF BORON ON CREEP DUCTILITY AND CREEP RUPTURE LIFE IN 9CR-1.5MO STEEL
Authors: KIM BUMJOON , IM JIWOO , KIM MOON K. , LEE JONGHOON , LIM BYEONGSOO
Published: August 2010

In this study, the relationship between the creep ductility and rupture life of 9 Cr -1.5 Mo steel with boron addition at 600°C was investigated by small punch (SP) creep test from the viewpoint of the modified Monkman-Grant relation. The amount of boron addition ranged from 0.0076wt% to 0.0196 wt%. The general concept of Monkman-Grant ductility for uniaxial creep was introduced and then particularly modified for the SP creep. The microstructure of the steel was observed to analyze the effect of boron addition on the creep ductility and rupture life. Based on the modified Monkman-Grant ductility for SP creep, it was found that the boron addition improved the creep ductility and rupture life of the 9 Cr -1.5 Mo steel. Also, the relationship between the minimum creep displacement rate and the amount of boron addition was analyzed.
EVALUATION OF CRACK INITIATION AND FATIGUE BEHAVIOR OF CrN FILM DEPOSITED ON Ti-6Al-4V ALLOY
Authors: RAHMAN MD. SHAMIMUR , KATSUMA TAKESHI , YONEKURA DAISUKE , MURAKAMI RI-ICHI
Published: August 2010

Titanium alloy has an attractive strength-to-weight ratio and good fatigue properties. However, the titanium alloy has very poor wear resistance, therefore, surface treatments must be considered in order to make the contact parts. Hard thin film deposited by PVD technique is well-known to improve the wear resistance. In this study, chromium nitride ( CrN ) film was applied to titanium alloy and its effect on the fatigue behavior was investigated. Ti -6 Al -4 V alloy was used as a substrate material. The CrN film was deposited by arc ion plating (AIP) method at two different negative bias voltages because the film hardness, crystal orientation and surface morphology were strongly depended on the bias voltage during the deposition. Tension-tension fatigue test and tensile test were carried out to investigate the fatigue properties. As the result, the fatigue strength was influenced by the deposition of the CrN film, especially, the fatigue strength was remarkable decreased by the deposition of the CrN film at high negative bias voltage compared to the uncoated specimen and the deposition of the CrN at low negative bias voltage. The difference of the fatigue strength was also investigated on the basis of crack initiating behavior during fatigue test and tensile test.
INJECTION MOLDING OF FLAT GLASS FIBER REINFORCED THERMOPLASTICS
Authors: TANAKA KAZUTO , KATAYAMA TSUTAO , TANAKA TATSUYA , ANGURI AKIHIRO
Published: August 2010

During an injection molding of composite materials, fiber attrition occurs and the average fiber length is reduced. In order to control the breakage of fibers and degradation of mechanical properties during processing, Flat glass Fiber (FF), that has oval cross-section shape, has been developed to use for glass fiber reinforced thermoplastic (GFRTP). Using FF as reinforcement of GFRTP has advantages as following: (1) Fluidity of FF is better than conventional Normal glass Fiber (NF) with 'circular' cross-section; (2) Fiber breakage during the injection molding process using FF is smaller than that using NF. In this study, the mechanical properties of FF and NF were compared for reinforcement of long fiber thermoplastics pellets (LFT pellets). We have also investigated the effect of screw design on fiber damage and the mechanical properties. The mechanical properties of specimens molded by FF reinforcement LFT (FF-LFT) pellets were superior to these of NF reinforcement LFT (NF-LFT) pellets. The former could give composites with higher fluidity and longer residual fiber length. Moreover, FF was able to strengthen injection-molded samples with higher fiber content than NF. Low shear type screw was effective to prevent the fiber attrition during plasticization process, hence leads to better mechanical properties of GFRTP
A STUDY ON FRETTING FATIGUE LIFE IN ELEVATED TEMPERATURE FOR INCOLOY 800
Authors: KWON JAE DO , WOO SEUNG WAN , CHUNG IL SUP , YOON DONG HWAN , PARK DAE KYU
Published: August 2010

Incoloy 800, which is used within steam generator tubes, is a heat resistant material since it is an iron-nickel-chromium alloy. However, construction of a systematic database is needed to receive integrity data defecting insurance of specific data about room and elevated temperature fretting fatigue behavior for Incoloy 800. Accordingly, this study investigates the specific change in fatigue limitations under the condition of the fretting fatigue as compared to that under the condition of the plain fatigue by performing plain and fretting fatigue tests on Incoloy 800 at 320°C, real operating temperature and at room-temperature, respectively. The change in the frictional force is measured during the fretting fatigue testing against the repeated cycle, and the mechanism of fretting fatigue is investigated through the observation of the fatigue-fracture surface.
A STUDY ON THE EVALUATION OF SHOCK ABSORBING PERFORMANCE FOR DOMESTIC ARTIFICIAL TURF GROUND
Authors: CHUNG MYUNG-JIN , OH SEONG-GUK , KANG KI-WEON
Published: August 2010

This paper deals with a device and method for measuring the impact properties of artificial turf surface using the accelerometer. Recently, the number of artificial turf ground is increasing according to holding a variety of international games and change of school play ground to artificial turf from clay. Artificial turf ground is required to meet standard certification to play international game. This standard certification is given by shock performance test during the specified period. The automatic shock evaluation system for shock absorbing performance test of artificial turf ground is proposed. This system consisted of auto carriage moving module, auto shock performance testing module, and auto data acquisition. Experiment is conducted to verify the performance of developed automatic shock evaluation system for shock absorbing performance test of artificial turf ground. From the performance test, developed automatic shock evaluation system has drop height of 55mm with resolution of 0.5mm, resolution of ±1% for operating range, measuring acceleration of over 50g, sampling frequency of over 10kHz, image resolution of over 12bit.
POSTERIOR CRUCIATE LIGAMENT (PCL) RECONSTRUCTION BY TRANSTIBIAL TUNNEL: SUGGESTIONS OF LENGTHENING AND SLIPPAGE RATIO
Authors: KIM JAY-JUNG , KIM CHEOL-WOONG
Published: August 2010

This paper examined the biomechanical fatigue behavior of Achilles tendon autograft after posterior cruciate ligament (PLC) reconstructions. It experimented with various fixation devices and locations on the degree of initial lengthening and slippage to investigate the relationship between lengthening and slippage ratios among calcaneal and soft tissue fixation methods. Eight specimens of proximal tibia and Achilles tendon grafts were harvested from cadavers and classified into four groups according to the type of transtibial fixation technique. A cyclic load ranging from 50N to 250N was applied to each graft when fixed to the proximal tibia at 55 degrees. The soft tissue fixation method, which uses an interference screw, demonstrated a 56.4% ratio of slippage to total elongation. The use of a double cross-pin with the same method demonstrated a 45.4% slippage ratio. The former was associated with approximately 2 mm less total elongation and 13% more slippage than lengthening compared to the latter. This result was predominantly due to the poor standard of fixation compared to the same method using a double cross-pin.
DEGRADATION MECHANISMS AND MECHANICAL PROPERTY VARIATION OF EPDM RUBBERS FOR AUTOMOTIVE RADIATOR HOSESS
Authors: KWAK EUNG-BUM , CHOI NAK-SAM
Published: August 2010

The degradation behaviors of EPDM (ethylene-propylene diene monomer) rubbers used for automotive radiator hoses subjected to thermo-oxidative and electrochemical stresses were studied. As a result of the thermo-oxidative aging tests, the IRHD (international rubber hardness degrees) hardness of the rubber specimens increased, while their elongation at break decreased much. A slight increase in crosslink density indicated that changes in the properties were caused by the concentration of carbonyl groups in the skin layer. For the electrochemical degradation (ECD), the weight of rubber specimens increased whereas their elongation and hardness much decreased because water solution penetrated into the skin part. There was little change in crosslink density. Formation of many chain scissions and thus microvoid networks in the skin layer induced the swelling behavior leading to a linear reduction of hardness versus the weight increase.
EFFECTS OF TIP MASS ON STABILITY OF ROTATING CANTILEVER PIPE CONVEYING FLUID WITH CRACK
Authors: SON IN SOO , YOON HAN IK , LEE SANG PIL , KIM DONG JIN
Published: August 2010

In this paper, the dynamic stability of a rotating cantilever pipe conveying fluid with a crack and tip mass is investigated by numerical method. That is, the effects of the rotating the rotating angular velocity, the mass ratio, the crack and tip mass on the critical flow velocity for flutter instability of system are studied. The equations of motion of rotating pipe are derived by using the extended Hamilton's principle. The crack section of pipe is represented by a local flexibility matrix connecting two undamaged pipe segments. The crack is assumed to be in the first mode of fracture and always opened during the vibrations. Finally, the stability maps of the cracked rotating pipe system as a rotating angular velocity and mass ratio β are presented.
EVALUATION OF THE JOINT-INTERFACE PROPERTIES OF SCM440-S45C STEELS JOINED BY FRICTION WELDING
Authors: KIM SEON-JIN , KONG YU-SIK , YOON HAN-KI , JUNG WON-TAEK , CHOI SUNG-WOONG
Published: August 2010

The purpose of this study is to investigate experimentally the hardness distributions and micro-structural properties of the dissimilar joints using chrome molybdenum steel (SCM440) to carbon steel (S45C) parts. The experiments were carried out using a beforehand designed and constructed experimental friction welding set-up, constructed as a continuous-drive brake type. The pilot dissimilar welding experiments under different friction pressure and friction time were carried out to obtain optimum welding parameters using visual examination and tensile tests. Vicker's hardness distributions and microstructures in the interfaces of the dissimilar joints for PWHT were also obtained and examined. The obtained results were compared with those of the previous study.
AN OPTICAL METHOD FOR THE ELASTIC MODULUS MEASUREMENT OF BIO-STRUCTURES
Authors: HWANG DO-SOON , JIN TAILIE , GOO NAM SEO
Published: August 2010

An optical method has been applied to measure the elastic modulus of a beetle wing membrane. A specimen was prepared by cutting the beetle wing carefully to take a sample size of 5.0 mm in width and 7.5 mm in length. We used a scanning electron microscope for the exact measurement of the membrane thickness of a beetle wing. It was attached to a fixture in order to induce a uniform displacement using a micromanipulator. We measured the applied load by the use of a load cell with a maximum capacity of 5 N and the corresponding displacement was measured by means of an ARAMIS system based on the digital image correlation method. The measured thickness of the beetle wing varied from point to point of the wing part and the elastic modulus was different according to the loading direction. In conclusion, we successfully measured the elastic modulus of a beetle wing with an ARAMIS system based on an optics based measurement method.
TRIBOLOGICAL PROPERTIES OF AG/BSCCO SELF-LUBRICATING COMPOSITES
Authors: DONG LIRONG , LI CHANGSHENG , HUA TANG
Published: August 2010

The superconductors Bi 2 Sr 2 CaCu 2 O x ( Bi 2212 ) and Ag / Bi 2212 composites samples were prepared by the powder metallurgy method. The frictional behaviors of Bi 2212 pins in contact with stainless steel plate were examined from -196 to 20°C on friction and wear tester. When the temperature was lower than the superconducting transition temperature, the friction coefficient of Bi 2212 dropped sharply, and it kept 0.11 with increase of the test time. The microstructure and morphology of Ag / Bi 2212 composites were investigated by means of X-ray diffraction (XRD), transmission electronic microscope (TEM) and high resolution transmission electronic microscope (HRTEM). The elemental compositions of the worn surfaces of Ag / Bi 2212 composites were determined by using energy dispersive X-ray analysis (EDXA). The results showed that the superconducting structure of Bi 2212 was not changed and Ag was distributed in the Bi 2212 matrix. Ag doping improved the toughness of oxide ceramics Bi 2212. The friction test results of Ag / Bi 2212 composites showed the tribological properties were improved at room temperature. The friction coefficient of 10% Ag / Bi 2212 against stainless steel showed a lower value (0.2) and the wear rate of 15% Ag / Bi 2212 was minimum (9.5×10-5 mm3·(N·m)-1 ). The lubrication of soft metallic film and load of hard matrix were the mechanism of decreased friction and anti-wear of Ag / Bi 2212 composites.
VALIDATION OF THE USE OF FRACTIONAL QUANTITATIVE COMPUTED TOMOGRAPHY BASED ON THE MECHANICAL PROPERTIES OF TRABECULAR BONE
Authors: LEE JONG MIN , CHANG YONG MIN , JIN GUANG HU , KIM JONG HYOUNG , SUH CHANG MIN
Published: August 2010

The fractional quantitative computed tomography (fQCT) to determine both quantity and distribution of bone mineral was evaluated based on the mechanical properties of trabecular bone. Using quantitative computed tomography (QCT), bone mineral density was measured at 46 areas from 5 bovine tibias. Subsequently, fQCT was measured by the proportion of pixels showing a bone mineral density greater than 290 mg/ml. Based on the mechanical properties of the bone specimens, the QCT and the fQCT were compared. The fQCT showed a significant correlation with the compressive strength with superiority to the QCT.
PLASMA TREATMENT OF CIIR RUBBER WITH IMPROVEMENT OF ADHESION AND REAL CONTACT AREA
Authors: KIM JONG-HYOUNG , NITTA ISAMI , UMEHARA NORITSUGU , KOUSAKA HIROYUKI , SHIMADA MAMORU , HASEGAWA MITSURU
Published: August 2010

The adhesion force between a chloride-isobutene-isoprene rubber (CIIR) and stainless steel ball was studied. To decrease the adhesion force, the CIIR rubber was treated with high-density microwave plasma employing oxygen and argon gases. The experimental results showed that the adhesion force decreases with increasing the time of oxygen and argon plasma treatments. In addition, the contact microscope measurements revealed different surface structure with two gases. The real contact area also decreased with treatment time and dramatic changes were observed after 5 min treatment of CIIR rubber. The field emission scanning electron microscope image also showed that the subsurface of CIIR rubber pattern has changed with various plasma treatments. These results imply change in the morphology of CIIR rubber surface by plasma treatment is one reason for the decrease in adhesion forces.
EFFECT OF DIFFERENT PRETREATMENTS TO ELECTROLESS NICKEL OR COBALT PLATING ON HOLLOW MICROSPHERES
Authors: ZHAO YAN , ZHANG RUN , ZHANG TONG , DUAN YUEXIN
Published: August 2010

Different pretreatment methods for electroless nickel and cobalt plating are demonstrated and compared in the present investigation. The surface morphologies of the nickel or cobalt deposits are investigated by scanning electron microscopy (SEM), and the chemical compositions of the coatings are analyzed by energy-dispersive X-ray spectroscopy (EDX). Method of single-step pretreatment is selected as the optimized method for electroless nickel plating process, while improved two-step sensitization-activation and single-step pretreatment methods can be selected for electroless cobalt plating. It can be found that the content of free Co is much lower compared to electroless Ni plating.
CONVERGENCE RATE OF THE SUCCESSIVE ZOOMING GENETIC ALGORITHM FOR BAND-WIDTHS OF EQUALITY CONSTRAINT
Authors: KWON Y. D. , HAN S. W. , DO J.W.
Published: August 2010

Modern optimization techniques, such as the steepest descent method, Newton's method, Rosen's gradient projection method, genetic algorithms, etc., have been developed and quickly improved with the progress of digital computers. The steepest descent method and Newton's method are applied efficiently to unconstrained problems. For many engineering problems involving constraints, the genetic algorithm and SUMT1are applied with relative ease.

Genetic algorithms2have global search characteristics and relatively good convergence rates. Recently, a Successive Zooming Genetic Algorithm (SZGA)3,4 was introduced that can search the precise optimal solution at any level of desired accuracy. In the case of engineering problems involving an equality constraint, even if good optimization techniques are applied to the constraint problems, a proper constraint range can lead to a more rapid convergence and precise solution.

This study investigated the proper band-width of an equality constraint using the Successive Zooming Genetic Algorithm (SZGA) technique both theoretically and numerically. We were able to find a certain band-width range of the rapid convergence for each problem, and a broad but more general one too.
MATHEMATICAL APPROACH AND GENERAL FORMULATION FOR ERROR SYNTHESIS MODELING OF MULTI-AXIS SYSTEM
Authors: LEE DONG-MOK , YANG SEUNG-HAN
Published: August 2010

Improving position accuracy of multi-axis machine tools is widely researched. The best known and widely used parametric approach models the direct kinematics of the work-piece and tool kinematic chain and use error synthesis modeling composed of homogeneous transform matrix (HTM). With respect to five axis machine tools, the increase in the number of axis and consideration of different configuration make computation of error matrices difficult and result in long error equations. In addition it becomes difficult to interpret the physical meaning of error terms in these equations. This work presents a mathematical formulation of error synthesis modeling for multi-axis system with the general joint series. This formula can be applied to all possible configurations.

The geometric model for an arbitrary joint is defined which is applicable to either prismatic or rotary joint. The error synthesis model for any configuration can be computed from the kinematic chains of a series of arbitrary joints. The proposed model consists of combination of error components of each local axis. Hence it is intuitive and easy to understand the effect of origin offset of local coordinates and squareness error with reference to the measurement coordinate.
EFFECTS OF 4D TRANSITION METALS ON NIAL BONDS CHARACTERS FROM FIRST PRINCIPLES
Authors: SHANG JIA-XIANG , YU TAN-BO , YU XIAN-XIANG
Published: August 2010

We study systematically the site occupancy and effects of alloying element on NiAl bonds character of 4d transition metals by first-principles method based on density functional theory. The impurity formation energies of 4d TM of NiAl in Al -site and Ni -site are calculated. Y , Zr , Nb , Cd prefer to occupy the Al -site, whereas Mo , Tc , Ru , Rh , Pd , Ag prefers to occupy Ni - si te. Crystal distortion and the overlap population between the alloying element and its first-neighboring atoms and are also calculated. The result shows that the substituting Al -site the elements Y , Zr , Nb , Cd interact with its first-neighboring Ni atom by anti-bonding. The total covalent ratio is decreased by theses elements which may improve ductility of NiAl . For Ni -site elements, the interaction between the alloying element Mo ( Tc , Ru , Rh , Pd , and Ag ) with its first-neighboring atoms Al also shows decrease in covalent. Site occupation of 4d transition metals are also discussed by the reaction energy for formation Ni 2 TiX and X bulk phase.
A CRACK GROWTH MODEL BASED ON FATIGUE DAMAGE ACCUMULATION
Authors: QIU BAOXIANG , WANG XIAOGUI , GAO ZENGLIANG
Published: August 2010

A novel model for predicting the fatigue crack growth had been developed based on the concept of the fatigue damage accumulation. Fatigue crack growth was considered as a process of continuous crack nucleation. The crack tip failed to form a fresh crack while the accumulative fatigue damage reached the critical damage. A simplified model of the general crack growth model was proposed with the assumption that the damage zone can be divided into many different zones and each zone had the same crack growth rate. The model was applied to predict the crack growth of the compact specimen made of 16MnR steel under the constant amplitude loading. The predicted crack growth rate was in excellent agreement with the experimental observations.
A STUDY ON THE EARTHQUAKE RESPONSE CHARACTERISTIC OF HYSTERESIS DAMPER USING SLY120 AND SS400
Authors: CHOI JAE HYOUK , TAKISHITA RYOUICHI
Published: August 2010

To examine earthquake response characteristics of hysteresis damper using SLY120 and SS400 steel panel damper, earthquake response test were performed. In this paper, restoring force characteristic of hysteresis damper which is obtained by loading test are assessed using numerical analysis model. A skeleton shift model, which has been used frequently in conventional analysis, is applied. Using a hybrid earthquake response test system, various characteristics of structural components that are difficult to model and to express mathematically are detected by test and incorporated into the computer system to promote numerical analysis of the whole system. In this research, hybrid earthquake response simulation of the linked vibration suppression structure is carried out, whereas hysteresis damper at the linked vibration control structure are selected as the actual loading test part and the peripheral frame is considered to be the virtual structure part.