bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methods of Evaluating the Performance of Fiber-Reinforced Concrete
Authors: Johnston Colin D. 
Published: March 2011

AbstractThree of the most important properties of fiber-reinforced concrete (FRC) are strength, toughness and resistance to cracking. The various methods of evaluating them are compared in terms of underlying rationale, ability to characterize composite material behavior in a readily understandable manner minimally affected by testing variables, and suitability for routine use in specifying and controlling concrete quality. The scope includes dynamic loading tests, slow-rate (static) loading tests, and tests to evaluate cracking induced directly by load or indirectly by restraint during shrinkage or thermal change.Consideration of the advantages and disadvantages of the various alternatives shows that slow flexure testing in accordance with the rationale developed by the writer and incorporated into ASTM standard C1018 effectively characterizes the FRC in terms of first-crack strength, toughness, and residual strength after first crack up to any predetermined level of serviceability expressed in terms of maximum permissible deflection. Although not part of the standard, resistance to cracking under load may also be assessed by measuring crack widths at appropriate deflections.
First and Second Order Structural Approaches to Steel Fibre Reinforced Concrete
Authors: Stroeven Piet 
Published: March 2011

AbstractGlobal and local information on distribution parameters of steel fibres in fibre reinforced concrete form essential ingredients in pursuit for further development of micromechanical, fracture mechanical or even composite modelling of such materials in the pre- and postcritical ranges. Additionally, quantitative image analysis approaches to specimens of such composites can be executed more effectively when based on proper structural models. This paper outlines first and second order stereological methods for that purpose.
The Interface Between Zinc Phosphate-Deposited Steel Fibers and Cement Paste
Authors: Sugama Toshifumi , Gray Gwen 
Published: March 2011

AbstractIn an attempt to protect steel fiber reinforcements from corrosion and improve the adherence of cement pastes to steel fiber reinforcement, we deposited a zinc phosphate (Zn-Ph) conversion coating on the surface of the fibers. At the interfacial contact zones between the cement paste and Zn.Ph, the alkali-induced dissolution caused the dissociation of abundant PO43- ions from the Zn-Ph. The interaction of PO43- ions with Ca2+ ions from the pastes led to the formation of hydroxyapatite and brushite in the vicinity of the dissolved Zn.Ph surface. Such intermediate Ca-phosphate compounds played important roles 1) in improving the cement-fiber interfacial bonds, and 2) in repairing the damage of the Zn.Ph surface dissolved by alkali. These processes protected the steel fiber from corrosion.
Influence of Interface Modification in Fiber Reinforced Cement Composites on Their Properties
Authors: Yuan Chen Zhi , Hua Cheng Qing , Feng Gao 
Published: March 2011

AbstractThis research aims at a further exploration of surface treatments of carbon fibers to improve the performance of CFRC. Two approaches to treat carbon fibers were used in this study. SEM, IR, XRD were used to analyse the CFRC prepared with treated carbon fibers. Because of strong adhesion, CFRC prepared using CF with treatment has a better performance than that without treatment. Flexural strength is 30% higher, tensile strength is 48% higher, impact strength 63% higher, and deflection is increased.
Development of Composites Reinforced by Polyester Fibres
Authors: Jelidi Ahmed , Chabannet Michel , Ambroise Jean , Pera Jean 
Published: March 2011

AbstractUntil now, the use of untreated polyester fibres in concrete has been delayed because these fibres are not alkali-resistant. To understand the fundamental mecanisms of degradation of such fibres in a cementitious matrix, some physico-chemical experimental techniques (SEM - EDAX - I.R. Spectrometry) associated with flexural tests were used. The degradation of polyester is caused by a saponification reaction and the toughness of the fibre-reinforced composite is quickly reduced.To prevent such a damage and develop tougher composites, the authors modified the cementitious matrix. Adding burnt clays (kaolin and montmorillonite) to OPC enabled the polyester fibre to withstand the alkaline attack.
Toughening of Cement-Based Materials with Fiber Reinforcement
Authors: Shah S. P. 
Published: March 2011

AbstractToughening of cement-based materials when reinforced with relatively high fiber volume is studied in the paper. Toughening mechanisms of composites have been experimentally studied by quantitative image analysis, laser holographic interferometry, and acoustic emission. It is found that damage localization in cement-based materials can be greatly reduced by the use of fibers. Based on fracture mechanism observed, an R-curve approach has been proposed to predict toughening of matrices due to fiber reinforcement. Theoretical predictions show good agreement with experimental results.
Evaluation of Toughness and Flexural Strength of Fiber Reinforced Concrete
Authors: Kubo Mitsuru , Mashima Mitsuyasu , Iwamoto Kaoru 
Published: March 2011

AbstractFiber reinforced concrete was developed to improve the mechanical properties of cementitious materials. Especially by using FRC, the structural mechanical properties after the maximum load can be improved. In the present study the mechanical properties of the fiber reinforced concrete are evaluated by investigating the influence of various parameters on the complete load-deflection curve, including the descending branch.
High Durability Glass-Fiber Reinforced Modified Cementitious Matrix
Authors: Thiery J. , Vautrin A. , Francois-Brazier J. 
Published: March 2011

AbstractIn AR-GFRC growth of hydration products around the filaments plays a dominant role in inducing embrittlement of the fibers and loss of toughness of the composites.The purpose of this paper is to present the way to limit the anchorage of the fibers in the matrix and to obtain a long term flexural strength of 30 MPa and an ultimate strain of 0,7 %. The improvement of the matrix is obtained by using selected metakaolinites and acrylic polymers in order to optimize the nature of the hydrates in the interface between the fibers and the matrix.The mecanical properties and durability behaviours are reviewed using three accelerated ageing tests based on warm water, wet-dry cycles and freeze-thaw cycles. The toughness indices proposed by Shah, Ludirdja and Daniel [12] are calculated, pointing out the improvements of toughness and durability of the new V~trotex-Saint-Gobain AR-GFRC system.
Glass Fiber Composites Made with a Cement Based on a Hydraulically Active CaO-SiO2-Al2O3 Glass
Authors: Hommertgen C. , Odler I. 
Published: March 2011

AbstractGlass fiber reinforced cement pastes were prepared using a cement based on a hydraulically active glass in the system CaO-SiO2-Al2O3. The properties of such composites were compared with those made with ordinary portland cement.In all the studied materials the MOR and WOF values declined with time, however for different reasons.
Formation of Titanium Silicide by Multiple Arsenic Implantations and Ion Beam Mixing
Authors: Chen Po-Ching , Lin Jian-Yang , Hwang Huey-Liang 
Published: March 2011

AbstractTitanium silicide was formed on the top of Si wafers by arsenic ion beam mixing and rapid thermal annealing. Three different arsenic-ion mixing conditions were examined in this work. The sheet resistance, residue As concentration post annealing and TiSi2 phase were characterized by using the* four-point probe, RBS and electron diffraction, respectively. TiSi2 of C54 phase was identified in the doubly implanted samples. The thickness of the Ti silicide and the TiSi2/Si interface were observed by the cross-sectional TEM.
Temperature Uniformity Optimization Using Three-Zone Lamp and Dynamic Control in Rapid Thermal Multiprocessor
Authors: Apte Pushkar P. , Wood Samuel , Booth Len , Saraswat Krishna C. , Moslehi Mehrdad M. 
Published: March 2011

AbstractRapid thermal processing (RTP) can play an important role in in situ single-wafer thermal multiprocessing, since it allows for a rapid wafer throughput rate. Conventional dedicated RTP equipment, where temperature uniformity is achieved by optimized reflector and chamber geometries for a specific process, typically cannot provide uniformity for different processes, or for a range of processing conditions. In this work we present a new flexible lamp system, in which tungsten-halogen lamps are configured in three concentric rings that are independently and dynamically controlled. The resultant circularly symmetric flux, which can be varied and controlled both temporally and spatially, offers significantly improved temperature uniformity. This is demonstrated using thermocouples as well as actual processes such as implant annealing, thermal oxidation and chemical vapor deposition of silicon. Through added flexibility and more precise control, this approach offers a powerful tool for multiprocessing and rapid process prototyping.
Contactless Measurements of Slip Lines Intentionally Introduced in Si Wafers During Rapid Thermal Processing
Authors: Usami A. , Shiraki H. , Fujiwara H. , Abe R. , Osamura N. , Ichimura M. , Wada T. 
Published: March 2011

AbstractThe slip lines introduced in Si wafers during rapid thermal processing (RTP) were revealed with focused reflectance microwave probe (RMP) method. The signal intensity of RMP which is related to optically injected excess carrier concentration decreases at slip lines. The region in which the signal intensity decreased is in good agreement with results of X-ray topography and theoretical analysis considering thermal stress caused by temperature drop at the wafer periphery during RTP. According these results, it is considered that carrier lifetime is decreased by slip dislocations which are effective recombination centers.
Ripple Technique; a Novel Non-Contact Wafer Emissivity and Temperature Method for RTP
Authors: Schietinger C. , Adams B. , Yarling C. 
Published: March 2011

AbstractA novel wafer temperature and emissivity measurement technique for rapid thermal processing (RTP) is presented. The ‘Ripple Technique’ takes advantage of heating lamp AC ripple as the signature of the reflected component of the radiation from the wafer surface. This application of Optical Fiber Thermometry (OFT) allows high speed measurement of wafer surface temperatures and emissivities. This ‘Ripple Technique’ is discussed in theoretical and practical terms with wafer data presented. Results of both temperature and emissivity measurements are presented for RTP conditions with bare silicon wafers and filmed wafers.
Application of RTP-CVD Technology to Ulsi Device Fabrication
Authors: Jung K. H. , Hsieh T. Y. , Kwong D. L. 
Published: March 2011

AbstractRapid thermal processing chemical vapor deposition (RTP-CVD) has received considerable attention as a novel in-situ multi-processing tool capable of meeting the stringent requirements of ULSI device fabrication. In this paper, we review the progress made in developing and applying RTP-CVD to ULSI device fabrication. Research areas discussed include epitaxial Si and poly-Si growth, in-situ doping, selective growth, in-situ multi-processing, and novel dielectrics. In addition, the extension of RTP-CVD to novel materials such as GexSi1−x has produced device quality films with successful application in HBTs and Si-based optoelectronics.
Si and GexSi1−x Epitaxial Growth on SOI Structures by Rapid Thermal Processing Chemical Vapor Deposition
Authors: Hsieh T. Y. , Jung K. H. , Kwong D. L. , Lin S. , Marcus H. L. 
Published: March 2011

AbstractA short time high temperature H2 pre-bake resulted in an undulating SIMOX surface, which planarized after epitaxial growth by rapid thermal processing chemical vapor deposition (RTPCVD). However, a short time, high temperature N2 pre-bake resulted in severe surface pitting. From dilute Schimmel etch results, no significant changes in the defect densities of the Si layers occurred after RTPCVD. Auger depth profiles of the SOI substrate prior to epitaxial growth show an oxygen peak in the SIMOX Si layer. However, the peak flattens out after epitaxial growth. Oxygen was not observed in the epitaxial film, even though oxygen was still observed in the SIMOX top Si layer.The use of GexSi1−x epitaxial layers to reduce threading dislocation densities was examined. A 1000°C Si buffer layer was first grown for 30s, followed by a GexSi1−x layer, and topped off by a 1000°C Si layer for 120s. The GexSi1−x layers were grown at temperatures varying from 850°C to 1000°C for 30s to 240s. The defect density was significantly reduced when the 900°C and 850°C GexSi1−x layers were used, although an increase in stacking fault densities (still small compared to threading dislocation densities) accompanied the lower deposition temperatures. The 1000°C GexSi1−x layer and a control sample in which pure Si was grown showed no significant decrease in defect densities.
Photo Induced Deposition of Thin Silicon Dioxide Films Using a Novel Large Area Excimer Lamp
Authors: Patel P. , Kogelschatz U. , Bergonzo P. , Boyd I. W. 
Published: March 2011

AbstractThere is a growing interest in the deposition and processing of thin films at low temperatures to eliminate the inherent problems associated with high temperature processing. Photo enhanced processing is one of the techniques which has received considerable interest. One of the major limitations of photo processing is the lack of sufficiently intense ultra-violet (UV) sources. To date the low pressure Hg lamp has been the only available source for large area UV processing and this has limited the types and quality of films deposited.In this paper we will outline the design of a novel, variable wavelength excimer discharge lamp which can be used for depositing thin films over large substrate areas. We shall also discuss the direct (i.e. without intermediate photosensitisation reactions) photo induced deposition of thin silicon dioxide films using SiH4 and N2O which are photo dissociated by 126nm photons generated by the excimer lamp described.
ArF Excimer Laser-Enhanced Photochemical Vapor Deposition of Homoepitaxial Silicon from Disilane
Authors: Fowler B. , Lian S. , Krishnan S. , Jung L. , Banerjee S. 
Published: March 2011

AbstractThe 193 nm output of an ArF excimer laser has been used to selectively photodissociate Si2H6 to deposit homoepitaxial Si films in the temperature range of 250°C to 350°C. Photolytic decomposition of Si2H6 results in the generation and adsorption of growth precursors on a hydrogenated Si surface. A simple growth kinetic model has been developed based on the most likely primary photofragments upon single-photon absorption by Si2H6 at the ArF excimer laser wavelength of 193 nm, and gas kinetic transport of the resulting photofragments to the substrate surface. Growth rates are observed to vary linearly with laser beam power and Si2H6 partial pressure when the laser beam is tangentially positioned less than 0.5 mm from the Si substrate for Si2H6 partial pressures less than 40 mTorr, total chamber pressures of 600 mTorr, and laser beam photon flux densities less than 2×1016 photons/cm2.pulse. Under these conditions, gas-phase diffusion dominates over chemical reaction rates and laser beam absorption is in the optically thin limit. The model then reduces to a simple form that predicts a linear dependence of growth rate on Si2H6 partial pressure and gives an accurate estimate of the expected growth rate. The epitaxial films are specular, and appear to have very low defect density in terms of stacking faults, as determined by modified Schimmel etching and Nomarski microscopy, and dislocation loops as determined by TEM (less than 105 loops/cm2). The crystallinity has been confirmed both by in situ RHEED, where we see a (l×l) streaky pattern, as well as selected electron diffraction, which shows a (100) crystalline orientation.
The Behavior of Free-Carriers During Rapid Thermal Annealing of Doped Silicon
Authors: Lojek B. 
Published: March 2011

AbstractRadiation and the resulting excess concentration of free carriers has a strong impact on several physical processes in silicon. New experimental results involving RTA are compared with previous experimental practice. Several aspects of the new result raise questions about the validity of the assumptions which were used in the past. It is concluded that radiation significantly enhances annealing processes, especially during the initial phase of RTA. Based on the study of the physical phenomena involved in the irradiated silicon, it is shown that the absorption and recombination rate are the most affected parameters and they are most likely the reason for the underestimation of the magnitude of excess free carriers.
Variation of Thermal Donors in Diffused Wafers by rapid Thermal Annealing
Authors: Sugiyama Takahide , Usami Akira , Ito Akira , Natori Taichi , Tokuda Yutaka , Wada Takao 
Published: March 2011

AbstractVariations of thermal donors (TDs) in highly phosphorus-diffused n-type silicon wafers (diffused wafer) have been studied with deep-level transient spectroscopy and capacitance-voltage measurements. The introduction and annihilation of TDs have been performed with heat treatment at 450°C and rapid thermal annealing (RTA) in the temperature range 600-900°C,respectively. In diffused floating zone-grown (FZ) silicon wafer, TDs were observed. It is thought that oxygen diffuses into FZ silicon during the diffusion process, since no TDs are generally formed in FZ silicon for the low oxygen concentration. The behavior of TDs in diffused wafer corresponded with that in oxygen-rich bulk silicon. TDs were completely annihilated by RTA at 700 and 800°C for the as-diffused wafers and the heat-treated ones at 450°C for 24 h, respectively, and the annihilation rate for the as-diffused wafers was fast, as compare to that for the heat-treated ones. This results may be caused by difference in the total concentration and cluster size of TDs.
Temperature Control and System Design Aspects in Rapid Thermal Processing
Authors: Roozeboom Fred 
Published: March 2011

AbstractThe main factors influencing the thermal performance (and thus product yield) of a rapid thermal processor are the heat source, the reaction chamber, the temperature measurement system, and as complicating factors, their total configuration and the optical wafer properties.The characteristics of 19 currently available commercial RTP systems are highlighted with focus on temperature control including the spectral characteristics and measures to suppress perturbations due to stray radiation.In addition recent developments and trends in the system configuration and in the optimization of temperature or layer thickness control are discussed. The improvements in temperature control focus especially on in situ temperature control, irrespective of wafer condition, and at system constructions that optimize dynamic temperature uniformity. Some novel optical process control and novel system design aspects to compensate for emissivity changes and temperature non-uniformity are included.
Studies of Oxygen Introduced During Thermal Oxidation and Defects Induced by Rapid Thermal Annealing in Silicon Epitaxial Layers
Authors: Usami Akira , Natori Taichi , Ito Akira , Sugiyama Takahide , Hirota Seiya , Tokuda Yutaka , Wada Takao 
Published: March 2011

AbstractIntroduction of oxygen during thermal oxidation and production of defects by rapid thermal annealing (RTA) in n-type epitaxial Si layers were studied with deep-level transient spectroscopy measurements. We use oxygen-related thermal donors (TDs) as a monitor for introduction of oxygen in silicon epitaxial layers. It is found that oxygen is introduced from the substrate into the epitaxial layer after thermal annealing. The TD was almost annihilated by RTA at .700°C. However, a shallow trap (Ec−0.073±0.005 eV) was induced by RTA.
Kinetics of Vacancy Ordering in YSi2−x Thin Film on Silicon
Authors: Lee T. L. , Chen L. J. , Chen F. R. 
Published: March 2011

AbstractHigh resolution and conventional transmission electron microscopy have been applied to study the interfacial reaction of yttrium thin films on Si. Epitaxial Ysi2−x film was grown on (111)Si by rapid thermal annealing at 500–1000 °C. The orientation relationship between yttrium silicide and (111)Si was determined to be [0001]Ysi2−x//[111]Si and (1010)Ysi2−x//(112)Si. The vacancies in the Ysi2−x film were found to be ordered in the Si sublattice plane and form an out-of-step structure. The range of M values of the out-of-step structure was found to narrow with annealing temperature and time. Defects along specific crystallographic directions were observed and analyzed to be intrinsic stacking faults.
Nucleation and Crystallization of Amorphous Silicon-Aluminum Thin Films
Authors: Lin F. , Hatalis M. K. , Girginoudi S. , Girginoudi D. , Georgoulas N. , Thanailakis A. 
Published: March 2011

AbstractThe phase transformation of amorphous silicon-aluminum thin films with 16 at.% and 30 at.% aluminum was characterized by TEM during an in-situ anneal at 500°C. No crystallization was observed in the samples having 16 at.% Al even after a 10 hour anneal at 500°C. In contrast, nucleation of crystallites was observed in the samples having 30 at.% Al after a 40 min anneal. The size of these crystallites grew during annealing. Single crystal regions were also observed and were identified as aluminum having <111> orientation.
Epitaxial Growth and Charge Density Wave of TaSe2
Authors: Shimada Toshihiro , Ohuchi Fumio S. , Parkinson Bruce A. 
Published: March 2011

AbstractWe report an epitaxial growth of TaSe2, a family of transition metal dichalcogenides that exhibit Charge Density Waves (CDW). The films that have been characterized with RHEED, LEED, XPS and STM showed two different phases. Occurrence of CDW in the ultrathin films has been detected by XPS and LEED.
The Relationship Between Crystal Structure and Performance as Optical Recording Media In Te-Ge-Sb Thin Films
Authors: Strand D. , Gonzalez-Hernandez J. , Chao B. S. , Ovshinsky S. R. , Gasiorowski P. , Pawlik D. A. 
Published: March 2011

AbstractThe crystallization properties of Te-Ge and Te-Ge-Sb alloys prepared by thermal evaporation were analyzed using various characterization techniques. Similar to previous results, our data for Te-Ge shows that alloys that deviate slightly from Te50Ge50 stoichiometry show drastically slower crystallization kinetics. Raman spectroscopy and x-ray diffraction show that alloys having non-stoichiometric atomic ratios phase separate during crystallization into a Te50Ge50 phase plus pure crystalline tellurium or germanium. It is this relatively slow process of phase segregation which limits the crystallization rate. Phase segregation during crystallization of non-stoichiometric Te-Ge can be eliminated by adding antimony to samples having a tellurium concentration of from 45 to 55 atomic percent over a wide range of Ge:Sb ratios. These alloys can have laser induced crystallization times of less than 50 nsec. The thermal crystallization temperature is reduced only slightly when antimony is substituted for germanium.