bluuebunny/crossref_metadata_2025 huggingface dataset:
3D Numerical Analysis for the Inelastic Deformation of Rubber Particle Modified Polymers
Authors: Wang Tie Jun , Zhang Wen Xu , Kishimoto Kikuo , Notomi Mitsuo
Published: March 2009

Body-centered cubic unit cell models and three-dimensional finite element method are used to study the inelastic deformation of rubber particle modified polymers. Calculations are carried out for three loading conditions, i.e. uniaxial loading, plane strain deformation loading and the so-called 'equivalent shear' loading. Distributions of the localized shear deformation are presented to understand the microscopic deformation mechanisms of the polymers. Effects of particle size, particle volume fraction and loading conditions on the micro- and macroscopic deformation
behavior of rubber particle modified polymers are discussed.
Quasicontinuum Models for Interface Multiscale Model
Authors: Hangai Y. , Yoshikawa Nobuhiro
Published: March 2009

A strategy of coupling length scales from atomistic to continuum is investigated on the basis of quasicontinuum model for interface fracture problems. In the model, an atomistic region of the interest is discretized by finite elements and the positions of atoms are prescribed by means of nodal displacements of the elements with shape function for the reduction of the degrees of freedom. Total energy of the system consists of interatomic potentials, and minimized through variational method employed in conventional finite element formulation. In this study, we deal with the fracture behavior of Cu-Fe interface crack in two dimensional problems, and investigate the adequate discretization manner around the crack tip in use of quasicontinuum method.
Inverse Analysis Method for Photoelastic Measurement of 3D Stress State
Authors: Wijerathne M.L.L. , Oguni Kenji , Hori Muneo
Published: March 2009

A new nondestructive method for identifying boundary conditions applied on a 3D linear elastic body is developed based on the load incremental approach, which linearizes the nonlinear governing equation of photoelasticity by considering small increments in applied load. Direct stress identification based on load incremental approach is highly sensitive to measurement errors and involves considerable amount of computations. On the other hand, identification of boundary conditions based on load incremental approach and thereby the state of stress is not only less
sensitive to measurement errors but also involves less computation. This boundary conditions identification can be considered as an introduction of equilibrium condition and the property of linear elasticity to overcome the shortcomings of direct stress identification.
Design Sensitivity Analysis and Optimization of Nonlinear Anisotropic Structures
Authors: Lee Tae Hee , Jung J.J.
Published: March 2009

Nonlinear analysis of anisotropic structures is described by using Hill's yield criterion that anisotropic yield contour is assumed to be retained its shape during the hardening process. Nonlinear constitutive equation of anisotropic material is derived using plastic potential concept. Linear strain hardening model is utilized and forward Euler method is employed as a stress integration method. Newton-Raphson method is implemented for numerical nonlinear analysis. Direct differentiation method differentiating directly the equilibrium equation with respect to design variables is applied to design sensitivity analysis of nonlinear anisotropic plate. The results of
design sensitivity analysis are compared with those of finite difference method to verify the accuracy. Optimization is accomplished for a rectangular plate using evaluated sensitivity coefficients.
Shape Optimization of a Structure with a Crack for Prolonging Fatigue Life
Authors: Han Seok Yoon
Published: March 2009

Shape optimization a cantilevered beam in mixed mode for prolonging fatigue life was accomplished by the linear elastic fracture mechanics and the growth-strain method. Linear elastic fracture mechanics (LEFM) was used to evaluate the stress intensity factor and fatigue life. The growth-strain method was used to optimize a shape. From the results, it was found that the optimal shape of a cantilevered beam greatly prolongs their fatigue life, and the growth-strain method is an appropriate technique for shape optimization of a structure having a crack.
Time of Flight Diffraction Method Using Laser Ultrasound for Noncontact Flaw Height Measurement
Authors: Mihara T. , Otsuka Y. , Cho H. , Yamanaka Kazushi
Published: March 2009

We developed a laser TOFD (Time of flight diffraction) algorithm which utilizes not only longitudinal wave but also shear wave. This algorithm made it possible to obtain accurate flaw depth without knowing the specimen velocity and probe distance previously. We constructed the laser TOFD system and applied it to estimate the slit depth of aluminum alloy plate. Time of flight of lateral wave, flaw tip diffraction waves and mode converted shear wave at flaw tip were used to estimate the slit depth using new algorithm.
Stress and Electric Fields in a Rectangular Piezoelectric Body with a Center Crack under Anti-Plane Shear Loading
Authors: Liu Shu Hong , Zou Z.Z. , Xu B.Q. , Li Han Yun
Published: March 2009

The problem involving a center crack in a rectangular piezoelectric body under anti-plane mechanical shear loading and plane electrical loading is analyzed for the permeable crack face conditions. The so-called general solutions of stress and electric fields are obtained, which is satisfied both the governing equations of anti-plane problems and the boundary conditions of the crack face. It is shown that electric field is nonsingular near right crack tip, while strain, stress and electric displacement have crack-tip singular behavior, the energy release rate has the same form as that without the electromechanical interaction, which is always positive. At last, the boundary collocation method is used to calculate the energy release rate. Numerical values are obtained to show the influence of the material properties and the electric field. The results show that the method of half analytical and half numeral is simple, accurate and widely applicable.
Grain Boundary Engineering for the Control of Mechanical Properties and Oxidation-Induced Embrittlement in Silicon Carbides
Authors: Tsurekawa Sadahiro , Watanabe Tadao , Tamari N.
Published: March 2009

Grain boundary engineering (GBE) is rapidly emerging recently as a powerful tool for achieving enhanced properties and performance in polycrystalline metallic materials. The objective of this work is to confirm the potential of GBE for enhancement in properties and performance in ceramic materials such as silicon carbide (SiC). Grain boundary microstructure in SiC could be tailored by doping with different elements (Mg, Al and P) and modifying sintering processing (hot-pressing and spark plasma sintering). FEG-SEM/OIM analyses revealed that both Al doping and SPS increased the frequency of low-energy special boundaries (Σ ≤29 ) and Mg doping enhanced grain growth. It was found that mechanical properties like microhardness depended on the grain boundary character
distribution (GBCD) and the grain size. The increment in the frequency of special boundaries could yield increases in the Vickers-microhardness and the fracture stress. Furthermore, intergranular oxidation-induced brittleness in SiC was noticeably improved by increase in the frequency of special boundaries and decrease in the grain size. Thus, we have confirmed that the control of grain boundary microstructure such as grain size, GBCD and grain boundary connectivity is a key for enhancement in bulk properties and performance in ceramic materials.
Low Vacuum Generation and Control on BIEN Technology: Mass Flow and Dry Pumping Characteristics
Authors: Lim Jong Yeon , Cheung Wan Sup , Choi Yong Moon , Seong Dae Jin , Shin Yong Hyeon , Chung Kwang Hwa
Published: March 2009

Since a clean environment and finite mass flow control on the molecular level are
continuously required in current R&D fields and actual process lines, technologies on vacuum generation and control have been playing a significant role in merging a variety of technologies like Bio, Information, Environment, Energy, Space and Nano.
Currently, the drive towards dry vacuum pumping has broadly occurred across a spectrum of vacuum applications, from semiconductor manufacture to industrial processing, due to its most visible advantages: it is contamination free. The integrated characteristics evaluation system for dry vacuum pumps has been established in KRISS in collaboration with several branch dry pump suppliers in Korea. The evaluation system exploits a constant volume flow meter to measure mass flow rates real-timely in standard level, and facilitates the evaluation of spatially averaged sound power levels using a semi-anechoic chamber. New and overhauled roots, claw, classical screw, and scroll type pumps supplied from the manufacturers have been evaluated using the evaluation system in terms of ultimate pressure, pumping speed, vibration, and sound power. We selected the mass flow measuring method with a constant chamber volume of 875 L because of its direct monitoring
capability which does not allow blind mass flow rate measurements, and proved that the method allows us to measure five decades of mass flow rates from 1×10-2 to 1×103 mbar-l/s with a measurement uncertainty of ±3%, which is within the internationally accepted standards limit. In this work, we demonstrate how the integrated pump characteristics evaluation and mass flow control method have been significant in the low vacuum range of 10-4 to 103 mbar.
Electrical and Optical Characterization of Energy States in Self-Assembled InAs/GaAs Quantum Dots with Size Distribution
Authors: Hwang Sung Ho , Lee Jung Il , Song Jin Dong , Choi Won Jun , Han Il Ki , Chang Soo Kyung
Published: March 2009

We report effects of the size and the energy state distribution on the electrical and optical properties in self-assembled InAs quantum dots. The results of characteristics measured using atomic force microscopy, photoluminescence and dark current are analyzed by way of a simulation assuming a Gaussian distribution in size and related energies. The samples investigated in this study are InAs/GaAs quantum dot infrared photodetector structures with an AlGaAs blocking layer grown
by molecular beam epitaxy at different growth modes.
Effects of Ag-Doping on Microstructure and Mechanical Properties of Hydroxyapatite Films
Authors: Park Sang Shik , Lee Hee Jung , Oh Ik Hyun , Lee Byong Taek
Published: March 2009

Ag-doped hydroxyapatite films were deposited on a ZrO2 substrate using r.f. magnetron sputtering to improve the bioaffinity and mechanical properties of the hydroxyapatite. The resulting hydroxyapatite films exhibited a variation in their microstructure and mechanical properties relative to the Ag content. The variation in the (Ca, Ag)/P ratios suggested that some of the Ca2+ ions in the hydroxyapatite were replaced with Ag+ ions. After annealing at 800oC, the hydroxyapatite films
showed a microstructure with crystalline nano-grains, whereas the Ag-doped hydroxyapatite films revealed the formation of crystallites embedded in the amorphous matrix. The hydroxyapatite films showed an average roughness of about 3~4nm, very smooth surface, and dense microstructure. The hardness and modulus of the films decreased with an increasing Ag content.
Immunization with Virus-Like Particle of Human Papillomavirus Type 16 L1 Elicits CTL Immune Response in C57BL/6 Mice
Authors: Pyo Hyun Mi , Park Jie Yun , Park Sue Nie , Kim Hyun Su , Shin Kee Sun , Poo Har Young
Published: March 2009

The development of a human papillomavirus vaccine has received a lot of recent attentiondue to the connection between HPV infections and cervical cancer. One promising vaccine to prevent HPV infections is an HPV virus-like particle, and various studies have already shown that HPV VLP immunization elicits a humoral immune response. However, cell mediated immunity is important for the prevention of HPV infections and cancer therapy. Therefore, to check the elicitation of a CTL
response by yeast-derived virus- like particles consisting of the HPV16 capsid protein L1, HPV16 L1 VLPs were produced and purified, then C57BL/6 mice immunized with the HPV16 L1 VLPs by subcutaneous injection. Thereafter, the splenocytes from the immunized mice were isolated and a chromium release assay performed using recombinant B16/HPV16 L1cells constantly expressing the
HPV16 L1 protein. As a result, the data demonstrated that the T cells from the HPV16 L1 VLP immunized mice exhibited a significantly higher cytotoxic T lymphocyte activity against the recombinant B16/HPV16 L1 cells than the T cells from the PBS immunized control mice.
A Modified Penna Model for Biological Aging
Authors: Kim Gi Ok , Shim Sugie
Published: March 2009

The Penna model for biological aging was modified. The reproducibility of each
individual was determined according to the number of mutations relevant at that time. The results of Monte-Carlo calculations using the modified model show that the ranges of the reproducible age are broadened as time goes by, thus showing self-organization in biological aging to the direction of maximum self-conservation. In addition, the population, survival rate, and average life span were calculated and analyzed by changing the number of new mutations at birth. It is observed that the
more the number of new mutations at birth is considered, the shorter the average life span that is obtained.
Effect of Initial Lean on Scaling of Postural Feedback Responses
Authors: Park Suk Yung , Horak Fay B. , Kuo Arthur D.
Published: March 2009

We examined how the central nervous system adjusts postural responses to an increased postural challenge due to an initial lean. Postural feedback responses scale to accommodate biomechanical constraints, such as an allowable ankle joint torque. Initial forward leaning, which is observed among the elderly who are inactive or afraid of falling, brings subjects near to the limit of stability and makes the biomechanical constraints more difficult to obey. We hypothesized that the
central nervous system is aware of body dynamics and restrains postural responses when subjects initially lean forward. To test this hypothesis, fast backwards perturbations of various magnitudes were applied to 12 healthy young subjects (3 male, 9 female) aged 20 to 32 years. The subjects were instructed to stand quietly on a hydraulic servo-controlled force platform with their arms crossed over their chests, then to recover from a perturbation by returning to their upright position, without stepping or lifting their heels off the ground, if possible. Initially, the subjects were either standing upright or leaning forward. The force platform was movable in the translational direction and programmed to move backward with various ramp displacements ranging from 1.2 to 15 cm, all with the duration of 275 msec. For each trial, the kinematics and ground reaction force data were recorded,
then used to compute the net joint torques, employing a least squares inverse dynamics method. Optimization methods were used to identify a set of equivalent feedback control gains for each trial so that the biomechanical model incorporating this feedback control would reproduce the empirical response. The results showed that the kinematics, joint torque, and feedback gains gradually scaled as a function of the perturbation magnitude before they reached the biomechanical constraint, and the scaling became more severe with an initial forward lean. For example, the model suggested that the magnitude of the ankle joint angle feedback to ankle torque was smaller in the leaning trials than in the initially upright trials, as if the subjects experienced a larger postural perturbation in the leaning trials. These results imply that the central nervous system restrained the postural responses to accommodate the additional biomechanical constraint imposed by the forward posture, thereby
suggesting that the central nervous system is aware of body dynamics and biomechanical constraints. The scaling of the postural feedback gains with the perturbation magnitude and initial lean indicates that the postural control can be interpreted as a feedback scheme with scalable gains.
Utilization of Markov Random Field for Large Images: Multiframe Work and Bayesian Approach
Authors: Jung Myung Hee , Yun Eui Jung , Byun Sy Woo
Published: March 2009

Markov Random Field (MRF) models have been successfully utilized in many digital image processing problems such as texture modeling and region labeling. Although MRF provides a well-defined statistical approach for the analysis of images, one disadvantage is the expensive computational cost for the processing and sampling of large images, since global features are assumed to be specified through local descriptions. In this study, a methodology is explored that reduces the
computational burden and increases the speed of image analysis for large images, especially airborne and space-based remotely sensed data. The Bayesian approach is suggested as a reasonable alternative method in parameter estimation of MRF models; the utilization of a multiresolution framework is also investigated, which provides convenient and efficient structures for the transition between local
and global features. The suggested approach is applied to the simulation of spatial pattern using MRF.
Goodness-of-Fit of Time Series Model for the Storage of Water in Agricultural Reservoir
Authors: Lee Hoon Ja , Ahn Tae Jin
Published: March 2009

The efficient management of the agricultural reservoir may well supply stable water for irrigation. In this article, time series analysis has been used for analyzing the storage of water data in Kihung agricultural reservoir that is located in Yongin City, Korea. For analyzing the storage of water data, three models, the ARIMA model, the autoregressive error model, and the dynamic regression model have been used. The result shows that the autoregressive error model is best suited for describing the storage of water data.
Schemes for Indoor Network Synchronization in UWB Positioning
Authors: Lee Hyo Jung , Lee Geuk , Kwon Young Mi
Published: March 2009

Location Positioning is a major technology for ubiquitous computing. A research on
Location Positioning using UWB is ongoing. In order to construct an indoor location network, synchronization of base stations is very important. NTP is popularly used as a clock synchronization protocol ranging from LAN to WAN. The Master-Slave scheme, however, is the simplest method for synchronizing an indoor network that uses UWB. In this paper, we compare and analyze the NTP and Master-Slave schemes according to the statistical channel model for an indoor multi-path propagation environment. Error ranges are calculated at various circumstances such as when the indoor network expands from one primary base station to several base stations. In particular, we compare the correctness of the NTP and Master-Slave synchronization methods. We have found that NTP is a more reasonable synchronization protocol in UWB positioning.
Motion Error Correction Scheme Using the Spatial Doppler Characteristics of the In-Scene Target in the SAR Imaging System
Authors: Choi Jeong Hee , Kim Eun Jung
Published: March 2009

The success of target reconstruction in the SAR(Synthetic Aperture Radar) imaging system is greatly dependent on coherent detection. Incoherent detection appears as a multiplicative phase error to echoed signal, which consequently causes fatal degradations such as fading or dislocation of target image. In this paper, we propose a motion error correction scheme using an in-scene target to
compensate for relative distance error between the radar and the target. We start by modeling from a wave equation for one point target, and then derive the complex motion error from extended overall echoed data. The proposed algorithm is also good for the correction of relatively large motion error because it can be applied repeatedly, and it is converged after each iteration. We use the spatial Doppler characteristics of the strong in-scene target to retrieve motion error, thus, we only used the partial spectral echo data corresponding to the strong in-scene target. By doing this, we can reduce computational loads and the number of iterations for the large motion error. We verify the performance of the proposed algorithm by applying it to the simulated spotlight-mode SAR data.
The Improved Binary Tree Vector Quantization Using Spatial Sensitivity of HVS
Authors: Kwak Nae Joung , Ryu Soung Pil , Kwon Heak Bong , Ahn Jae Hyeong
Published: March 2009

In this paper, we proposed an improved binary tree vector quantization in special
consideration of the area of spatial sensitivity which is an important characteristic of the human visual system. We regarded spatial sensitivity as a function of the human visual system, which works using variations of the three primary colors in blocks of input images. In addition, we applied the weight derived from HVS spatial sensitivity to the process of splitting nodes using eigenvectors in binary tree vector quantization. The test results showed that the proposed method provided better
visual quality and greater PSNR than conventional methods.
SRT Division Based on Redundant Signed Number
Authors: Han Seon Kyoung , Kim Yong Dae , You Young Gap
Published: March 2009

SRT division schemes are presented based on a redundant number operand format aiming high speed operation. The proposed SRT division method based on a redundant binary adder (RBA) and one based on a recoded binary signed digit adder (RBSDA) show a 33% and 50% speed improvement, respectively. The time complexity of the proposed division based on redundant number is O(n); importantly, the redundant number based design is easy to implement due to its structural regularity.
Image Indexing Based On Mpeg-7 Scalable Color Descriptor
Authors: Singh Kulwinder , Ma Ming , Park Dong Won , An Syungog
Published: March 2009

The MPEG-7 standard defines a set of descriptors that extract low-level features such as color, texture and object shape from an image and generate metadata that represents the extracted information. In this paper we propose a new image retrieval technique for image indexing based on the MPEG-7 scalable color descriptor. We use some specifications of the scalable color descriptor (SCD) for the implementation of the color histograms. The MPEG-7 standard defines 1 l norm − based matching in the SCD. But in our approach, for distance measurement, we achieve a better result by using cosine similarity coefficient for color histograms. This approach has significantly increased the accuracy of obtaining results for image retrieval. Experiments based on scalable color descriptors are illustrated. We also present the color spaces supported by the different image and video coding
standards such as JPEG-2000, MPEG-1, 2, 4 and MPEG-7. In addition, this paper outlines the broad details of MPEG-7 Color Descriptors.
Speciation of Six Arsenic Compounds in Korean Seafood Samples by HPLC-ICP-MS
Authors: Park Kyung Su , Kim Jeong Sook , Lee Hyo Min , Pyo Hee Soo , Kim Soon Tae , Lee Kang Bong
Published: March 2009

Extracts of 33 samples of seaweed, shrimp, fish and shellfish, including two certified
reference materials, were investigated for their contents of arsenic compounds (arsenic speciation).An anion exchange high performance liquid chromatography procedure was optimized to separate six arsenic compounds present in the seafood samples with dynamic reaction gas cell by inductively coupled plasma mass spectrometry. The concentration of each species in the sample were: arsenobetaines - 0.019-1.04 mg/kg, arsenocholine - 0.033-69.0 mg/kg, arseniousacid - ND-1.25 mg/kg, dimethylarsinate - ND-3.75 mg/kg, monomethylarsonate - ND-8.33 mg/kg, arsenic acid - ND-0.55 mg/kg. Additionally, unknown arsenic species were present in most of samples. The intake of inorganic arsenic via ingestion of the seafood samples that were analyzed did not represent a
toxicological problem to humans. The limits of detection (LOD) were in the range of 0.5-2.5 µg/kg .
Environmental Contamination of Heavy Metals and Effects of Sediment Bacteria on Cadmium Speciation in the Vicinity of the Hwacheon Mine
Authors: Lee Sung Eun , Lee Jin Soo , Chon Hyo Taek
Published: March 2009

In order to investigate the extent and degree of heavy metal contamination in soils and sediments influenced by past mining activities, and to estimate the effects of indigenous bacteria on Cd speciation and bioremoval efficiency in sediments according to the various environmental conditions, tailings, soils, waters and sediments were collected from the Hwacheon Au-Ag-Pb-Zn mine in Korea. Elevated levels of metals, i.e., 29 As mg/kg, 30 Cd mg/kg, 261 Cu mg/kg, 601 Pb mg/kg and 3128 Zn mg/kg were found in sediments. High concentrations of As and other heavy
metals in soils, waters and sediments were found near the tailings piles. From the results of sequential extraction analyses with tailings and soils, a high proportion of Cd is present as non-residual fractions. This indicates that Cd is more mobile and bioavailable than Cu, Pb and Zn. For seasonal variation, the concentrations of As and other heavy metals were much more elevated in soils collected before rainy
season than after rainy season. To estimate the bioremoval efficiency for Cd, bacteria which can adsorb Cd were isolated from sediments in this area. Microorganisms in sediments can alter the mobility of heavy metals and bacteria can leach heavy metals from sediments, adsorb them on their cell wall and accumulate them within an intracellular matrix. From the metal sorption tests with indigenous bacteria, the bioremoval efficiency of Cd in Cd single solution (10 ppm) was more than 90%. As well, the isolated bacterial strains exhibited a preferential metal sorption , i.e., Cd > Pb > Zn for single metal solutions and Pb > Cd > Zn for the mixed metal solutions. Therefore, the use of some microorganisms to remove heavy metals from contaminated sediments may represent an innovative purification process.
Similarity Theory, Intermittency and Turbulences in the Stable Boundary Layer
Authors: Ha Kyung Ja , Kim Kyung Eak , Hyun Yu Kyung , Jeon Eun Hee , Mahrt Larry
Published: March 2009

The evaluation of similarity theory, z-less formulation of turbulence, and validation for
various stable conditions is addressed with the use of CASES99 data over grassland. The dependence of the flux-gradient relationships on height and stability parameters is evaluated. For very stable conditions, similarity relation based on Monin-Obukhov theory is locally invalid and new treatments are required. The flux intermittency is recommended as a good indicator of stability for very thin stable boundary layer.
Radioprotective Effect of Ginsan through Stimulating the Hematopoiesis and Modulating Antioxidant Enzymes
Authors: Song Jie Young , Son Soo Jeong , Shim Ji Young , Ahn Ji Yeon , Kim Hyung Doo , Han Young Soo , Son Hyeog Jin , Hong Sung Hee , Yun Yeon Sook
Published: March 2009

An immunomodulator ginsan, polysaccharide isolated from Panax ginseng, showed a
mitogenic activity, generation of LAK cells, and the secretion of several cytokines. In the present study, we evaluated the protective effects of in vivo injected ginsan against irradiation. Ginsan was found to significantly increase the number of bone marrow cells, spleen cells and the number of circulating neutrophils, lymphocytes and platelets in irradiated mice. In addition, ginsan induced the production of a variety of cytokines such as IL-1, IL-6, IL-12, TNF-a and SCF, which are required
for a hematopoietic recovery and are closely correlated with the antioxidant defense systems. We demonstrated that the pretreatment with ginsan protected the mice from the lethal effects of ionizing radiation more effectively than given after the irradiation. A dramatic increase of the survival of the ginsan-treated group from LD50/30 7.54 Gy of the PBS-control group to 10.93 Gy was observed. Moreover, the levels of the antioxidant enzymes such as superoxide dismutase (SOD), catalase and gluthathion peroxidase (GPx) were increased 1.5-2 fold in the ginsan treated mice compared to the irradiated mice. In conclusion, our data suggests that the radioprotective action of ginsan in the irradiated mice may be due to not only to the rapid regeneration of hematopoietic cells but also to the modulation of antioxidant defense systems.
Assessment of WIMS-D5 Applicability to CANDU NPPs
Authors: Kim W.Y. , Min B.J.
Published: March 2009

The purpose of this study is to develop a WIMS/CANDU code for a lattice calculation on the basis of WIMS-D5 code for the safety analysis of CANDU reactors. To assess WIMS-D5 applicability to a CANDU reactor, a lattice model was developed for CANDU-6 reactors at the Wolsong site. As for the benchmark of the code validation, a code-to-code comparison was performed between the WIMS-D5 code with both the 69- and 172-energy groups of ENDF/B-VI nuclear data library and the WIMS-AECL code with the 89-energy group. The comparison studies of the reactor physics parameters such as the void reactivity and the coolant/fuel/moderator temperature coefficients were conducted with a change of the internal isotopic composition due to the fuel burning-up using both WIMS-AECL and POWDERPUFS-V (PPV) codes. The results show that the present results from WIMS-D5 code and WIMS-AECL code agreed well with those of the PPV at the beginning of the fuel burn-up phase. As the burning-up progresses, the results of
WIMS-D5 show a large deviation from those of PPV for the CANDU 6 reactors.
The Size Optimization of the Liquid Helium Pressurant Tank for Liquid Propellant Rocket
Authors: Park Youn Mi , In Seh Wan , Jeong Sang Kwon
Published: March 2009

An efficient and reliable pressurization system for an oxidizer and fuel of a liquid
propellant rocket is critical for a successful launch. A liquid helium pressurization system employing a heater can reduce its mass, and be made simpler and more reliable than conventional pressurization systems. The key issue to minimize the total mass of the system is the optimization of the size of the liquid helium tank. In this paper, we describe a method to determine the optimal size of a liquid helium tank, and present one set of results under a given set of requirements. In this pressurization system, the heater design is represented by the heater efficiency. To estimate the heater efficiency, the convection heat transfer coefficient should be known beforehand. The guideline how to estimate this convection heat transfer coefficient based on the preliminary experimental data is also presented in this paper.
Detection of Russian Fires Using MOPITT and MODIS Data
Authors: Lee Sang Hee , Choi Gi Hyuk , Lim Hyo Suk , Lee Joo Hee , Lee Kwon Ho , Kim Young Joon , Kim Jhoon
Published: March 2009

The great fires were detected through the Moderate Resolution Imaging Spectroradiometer (MODIS) observations over Northeast Asia. The large amount of smoke produced near Lake Baikal was transported to East Asia using high Aerosol Optical Thickness (AOT) as seen through the satellite images. The smoke pollution from the Russian forest fires would sometimes reach Korea through Mongolia and eastern China. In May 2003, a number of large fires blazed through eastern Russian, producing a thick, widespread pall of smoke over much of East Asia. This study focuses on the identification of the carbon monoxide (CO) for MOPITT released from MOPITT primarily into East Asia during the Russian Fires. In the wake of the fires, the 700hPa MOPITT retrieved CO concentrations which reached up to 250ppbv. Smoke aerosol retrieval using a separation technique was also applied to the MODIS data observed in 14-22 May 2003. Large AOT, 2.0 ~ 5.0, was observed over Korea on 20 May 2003 due to the influence of the long range transport of smoke aerosol plume from the Russian Fires.
Variable Star Identification in the BATC Field of M67
Authors: Kim Hwihyun , Byun Yong Ik
Published: March 2009

We present the result of photometric variability investigation for stars in the field of M67. The old open cluster M67, one of the most studied open clusters, shows the sign of significant main-sequence binary population in its color-magnitude diagrams. Identification of eclipsing binaries and follow-up studies will enable us to study the nature of binary population in most direct manner. We used approximately 350 images from the BATC (Beijing-Arizona-Taipei-Connecticut) data archive to examine variability within one square degree field centered on M67. A total of 18 stars were classified to be real variables. Our new discoveries include seven eclipsing binary systems of which two are likely to be W UMa systems. All of these variables were found using the phase dispersion minimization (PDM) method developed by Shin and Byun[11].
Interband Light Absorption in Semiconductor Quantum Dots Connected with the Charged and Neutral Exciton - Donor Complexes
Authors: Djotyan A.P. , Avetisyan A.A. , Kazaryan E.M.
Published: March 2009

The interband light absorption in spherical quantum dot (QD) of semiconductors
connected with the charged and neutral exciton-donor complexes are studied theoretically. The oscillator strength for interband optical transition from valence band to the ground state of excitondonor complex in spherical QD has been investigate. The calculations were performed in the cases of infinite and finite potential barrier of QD. The dependences of the oscillator strength on the radius of the QD were obtained. It was shown that the quantum confinement gives rise a giant
oscillator strength per impurity.
Grain-Size Effects and the Physical Properties of La0.7Ca0.3MnO3-δ
Authors: Lee H.K. , Baier Horst , Park J.S. , Lee Y.P. , Lee Youn Seoung
Published: March 2009

The effects of grain-size in La0.7Ca0.3MnO3-δ (LCMO) system have been studied in connection with the magnetic and electronic properties. LCMO system prepared by the solid-state reaction was annealed in air at 1200, 1300 and 1400°C. The grain sizes of LCMO samples become larger with increasing of annealing temperature (TA ). The magnetization in LCMO samples increased while the coercive field decreased with increasing TA. The conductivity increased and the metal-insulator transition temperature TM-I decreased with increasing of TA. These physical properties are due to the oxygen deficiency caused by the increase of grain size. Finally, it was found that the grain size and the mechanical connection between grains play an important role in determining the electronic and magnetic properties.
Preliminary Study of the Apparatus for Electron Stimulated Desorption of Rare Gas Solids
Authors: Hong Seung Soo , Chung Kwang Hwa , Shin Yong Hyeon , Sung Eun Jung , Arakawa Ichiro
Published: March 2009

An electron stimulated desorption (ESD) experimental system consisting of a ultrahigh vacuum chamber, micro channel plate, electron gun, quadrupole mass spectrometer, liquid helium and liquid nitrogen cryostat, and a gas supply tube etc., was set up and evaluated in order to investigate desorption particles at the surface of rare gas solids (RGS). Ar was deposited on the copper sample for 200 seconds at a pressure of 6.3 x 10–4 Pa. Ion currents from the RGS during
bombardment at various electron gun energies were measured. These increased proportionally with filament currents between 1.5 A and 1.75 A. With the electron gun turned on, the dominant residual species in the vacuum chamber were H2O, H2, C, O, N2, Ar, and CO2, as measured using a quadrupole mass spectrometer (QMS). The H2O partial pressure was almost 50 % of the total pressure, and that of the other gas species were lower than 20 %. Before starting the experiments,
the ultimate base pressure of the ultrahigh vacuum chamber reached 10–8 Pa.
Ethical Issues on Nanotechnology in Asia
Authors: Choi Kyung Hee
Published: March 2009

This paper examines the development of nanotechnology in Asian countries and existing and potential ethical issues related to the changes coming about with the development in the pertinent area. The paper further explores strategies aiming to prevent the negative consequences of this development. Nanotechnology does not negatively affect human dignity and integrity. However, just like when dealing with any technology, some of its applications may present certain risks. More attentive monitoring and control has to be enforced in the fields where technology is interconnected with living environment.
Photoluminescent Europium Complexes with Oxygen and/or Nitrogen Donating Ligands
Authors: Oh Yunghee , Lee Chul Ho , Lee Burm Jong , Shin Byoung Chul
Published: March 2009

The reaction of EuX3 ·nH2O (X=Cl¯ , NO3¯ ), a- pyridoin anion (P) and 2,2¢-dipyridylamine in ethanol solution yields a hydroxo complex, EuP2(OH) 2(H2O) 2, which is characterized by NMR, IR, and elemental analyses. Europium complexes coordinated by nitrogen donating ligands such as 2,2¢-dipyridylamine or 2¢-hydroxypyridine are unstable in solution and are prone to decompose to europium hydroxo complex and pyridinium amine salt. The UV and PL spectra of europium complexes are reported and a decomposition mechanism is proposed.
A Soft Ceramic Ti3SiC2 with Microscale Plasticity at Room Temperature
Authors: Li Shi Bo , Zhai Hong Xiang
Published: March 2009

Microscale plasticity of Ti3SiC2 was investigated by Vickers hardness indentation. The surface layer of the hardness indentations was removed by acid solution to observe microstructure beneath the indentations, where a large number of bending, delamination and kinking grains were found. These features suggest that Ti3SiC2 is able to consume microdamage around the indentations. Numerous basal plane dislocations and stacking faults lying in Ti3SiC2 grains or accumulating at grain boundaries were observed. The basal plane dislocations play an important role in the microscale plastic deformation. The plasticity and damage tolerance for Ti3SiC2 at room temperature should be attributed to multiple energy absorbing mechanisms: grains bending, delamination, kink-band formation, and the basal plane slip, etc.
Effects of Electrical Characters on Electrical Fatigue Behavior in PLZT Ferroelectric Ceramics
Authors: Chen Zhi Wu , Lu Zhen Ya , Chen Xu Ming , Zhang Ying , Cheng Xuan
Published: March 2009

Electrical fatigue tests have been conducted on PLZT ferroelectric ceramics. It was found that the higher the applied electrical field magnitude, the faster the Pr decreases; the samples under the same electrical field magnitude but with square wave have higher fatigue rate than that of sine wave. It was observed that at low frequency of applied field (50Hz and 500Hz), the polarization decreased very quickly and dropped below 70% of the original value within 106.2 switching cycles, however, when fatigue test were conducted at high frequencies of 100kHz and 300kHz, the polarization did not change significantly even after 109 cycles. The SEM analysis indicated that the facture mode was mainly of trans-granular for
the virgin non-fatigued sample, while of inter-granular for the fatigue sample. The quantitative information on the 90° domain switching was measured in situ using X-ray diffraction. The effects of electrical characters on electrical fatigue behavior were explained according to the mechanism of electrical fatigue in PLZT ferroelectric ceramics.
Preparation and Characterization of Compositionally Graded Epitaxial Barium Strontium Titanate Thin Films via Scanning Probe Microscopy
Authors: Lu Sheng Guo , Chen Haydn , Mak C.L. , Wong K.H. , Chan H.W.L. , Choy C.L. , Xu Jian Jun , Shi Shao Qiu
Published: March 2009

Epitaxially graded barium strontium titanate (BaxSr1-x)TiO3 (x = 0.75, 0.8, 0.9, 1.0, abbreviated as BST75, BST80, BST90 and BTO respectively) thin films were fabricated by pulsed laser deposition method on the (La0.7Sr0.3)MnO3 (LSMO)/LaAlO3 (LAO) single crystal substrate. Scanning probe microscopy with a contact mode was used to characterize the temperature dependence of polarization from room temperature to 140°C. Results indicated that the piezo-response signal of the BST graded films had an obvious change with temperature, and that the graded structures had a flatter temperaturedependence of permittivity. Furthermore, the contrasts of the SPM images were lower for the ferroelectric – paraelectric (F-P) phase transition temperatures of BST 75, BST 80, and BST90, but higher for the F-P transition temperature of BTO.
Structure and Piezoelectric Properties of PZN-PNN-PT Ceramics
Authors: Pan Jin Song , Zhang Xiao Wen , Chen Ke Pi , Lei Chao
Published: March 2009

(1-x)(0.64PNN-0.36PT)-x(0.91PZN-0.09PT) ferroelectric ceramics with different x were synthesized by the columbite precursor method. The phase structure and piezoelectric properties were investigated. XRD profiles implied that with the increasing of x, samples could no longer maintain the pure perovskite phase. All the compositions were found to lie within the region of the morphotropic phase boundaries (MPBs) with different contents of rhombohedral and tetragonal
phases. The piezoelectric coefficients for compositions with x £ 0.30 were obviously better than those for the rest ones and the composition with x = 0.15 exhibited the largest value of d33 among all the samples. The relationship between the structure and the piezoelectric properties was discussed.
Preparation and Magnetic Properties of Low Temperature Sintering Bi-Substituted Yttrium Iron Garnet
Authors: Zhao Hong Jie , Zhou Ji , Gui Zhi Lun , Li Long Tu
Published: March 2009

The low temperature sinterability and magnetic properties of Bi-substituted yttrium iron garnet (YIG) polycrystalline samples were studied in this paper. The results showed that Bi-substitution can lower garnet phase formation temperature from about 1200oC to 900oC and ceramic sintering temperature from over 1300oC to about 1050oC respectively. The Bi-substitution leads to a decrease in initial permeability and an increase in ferromagnetic resonance linewidth (ΔH)
of sintered specimens. Saturation magnetization decreases and coercive force increases a few with an increase of Bi content. The mechanism of Bi-substitution on initial permeability and ΔH is discussed. The change in initial permeability of Bi-substituted specimens relative to unsubstituted YIG results from Bismuth volatilization and weakening of superexchange interaction. The lattice dilatation in
Bi-substituted YIG gives cause for a decrease of saturation magnetization and an increase of coactivity force.
Micromorphologies and Defects in CVD ZnS and ZnSe
Authors: Fang Zhen Yi , Pan Wei , Fang Ming Hao , Shi Sui Lin
Published: March 2009

ZnS and ZnSe for infrared optical windows were fabricated by particular Chemical Vapor Deposition (CVD) process with so-called S method and Se method respectively. Their morphology and defects are reported in this paper. The microstructure, composition and the influence on optical properties of the defects were investigated. The process reasons leading to these defects were discussed as well. Hot isostatic pressing (HIP) treatment was adopted to eliminate some of the defects, and the effect of HIP on optical properties was evaluated.
Properties and Microstructure of Optically Transparent Polycrystalline Spinel
Authors: Huang Cun Xin , Li Jian Bao , Lei Mu Yun , Du Hong Bing , Yang Xiao Zhan
Published: March 2009

Fully transparent polycrystalline spinel(MgAl2O4)has been prepared by combined vacuum sintering and hot isostatic pressing. This paper investigated transparent polycrystalline spinel optical properties sintered in different atmospheres and discussed the effect of sintered processing parameters on the development of the microstructure and transmission properties. The optical transmittance of the specimen sintered at 1500°C following HIPed at 1800°C was nearly the same as that of single crystal spinel. The transmission properties of spinel can be improved with the increase of temperature and pressure of sintered/HIPed spinel. Specimens sintered in vacuum following HIP have higher transmittance than those sintered in air or in hydrogen.
Synthesis of Poly (Acrylic Acid-Co-Itaconic Acid) and its Dispersing Effect for Barium Titanate Aqueous Suspension
Authors: Wang Xi Xin , Zhao Jian Ling , Wang Xiao Hui
Published: March 2009

Dispersing barium titanate (BT) in aqueous media has received special attention due to economic and environmental considerations. A new kind of dispersant named poly (acrylic acid-co-itaconic acid) has been synthesized in our study. By adjusting reactant ratio and reactant condition poly (acrylic acid-co-itaconic acid) with different average molecular (2000~10000) and different content of itaconic acid (10% ~ 30%) have been obtained. Dispersing effects of poly (acrylic acid-co-itaconic acid) have been studied through zeta potential, sediment experiments, rheological behavior. It can be concluded from our study poly (acrylic acid-co-itaconic acid) containing 20% itaconic acid with Mw between 3000 and 5000 show the best dispersing effect.
Ceramic-On-Ceramic Implants in Total Hip Arthroplasty
Authors: Colwell Clifford W. , D'Antonio J.A. , Capello W.N. , Hardwick M.E.
Published: March 2009

Alumina ceramic is an excellent material for biologic implantation. Decreased particulate wear debris should increase implant longevity. The purpose of this study is to examine clinical and radiological results of ceramic-on-ceramic hip implants compared to cobalt chrome on polyethylene.
Four cementless systems were compared, three alumina-on-alumina bearing systems: System I, porous coated cup; System II, hydroxyapatite-coated cup; Trident system, hydroxyapatite-coated cup with metal sleeve backing on ceramic cup liner; and System III (control), porous-coated cup with polyethylene and cobalt chromium bearing system. Patients were randomized to receive System I,
II, or III. Trident patients were not randomized. Examinations are performed at 6 months, 1 year and yearly thereafter including x-rays, clinical exam and Harris Hip Score (HHS). Minimum 24-month followup was performed in 562 ceramic hips and 154 control hips. Age, height, weight, gender and diagnosis were similar in all groups. HHS was rated good/excellent by 95 percent of ceramic hips and 97 percent of control hips. Radiographic results demonstrated radiolucency in Femoral Gruen Zone 1 in 3.8 percent (18/474) of ceramic hips and in 8 percent
(10/128) of control hips. Unstable acetabular components were reported in none of ceramic hips and in 3.2 percent (5/154) of control hips. Revision was performed in 7 (1.2 percent) ceramic hips, none due to failure of ceramic materials, and in 9 (5.8 percent) control hips. Alumina ceramic materials
show promise, but continued evaluation of long-term clinical results is needed.
Development of an Alumina Ceramic with a Gradient of Concentration and Microstructure for the Application of Load Bearing Implants
Authors: Oberbach Thomas , Christoph Marita , Glien Wilfried
Published: March 2009

Alumina and zirconia have played an important role in joint endoprosthetics for the use in tribologically loaded implant components like hip joint heads and cups for years. In our investigations we prepared an alumina ceramic with a gradient in concentration of zirconia. The zirconia content was realized by infiltration processes with different ZrO2 – precursors. The material was characterized concerning ZrO2-distribution, infiltration depth and microstructure.
Preparation and Characterization of New Self-Setting Calcium Phosphate Cements Based on Alkali Containing Orthophosphates
Authors: Berger Georg , Gildenhaar Renate , Pauli Jutta , Marx Heidi
Published: March 2009

This paper deals with calcium phosphate cements containing alkali to achieve higher
solubility. Until now normally for all cements also if alkali was integrated the self-setting process leads to hydroxyapatite (HA) or calcium deficient HA (CDHA). In cases where fluid dispersions of HA were used for bone defect treatment the HA remains and do not acts self-hardening. The selfsetting cements show high compressive strength in comparison to the HA supplied as a paste. They show latent hydraulic behavior during the self-hardening process. The following storage in SBF for four weeks also did not lead to a strong change of the starting materials that were Ca2KNa(PO4)2 or Ca10[K/Na](PO4)7.