50,825 research outputs found
Synthesis of TiAl-based intermetallics with nanocrystalline structure by mechanical alloying and hot isostatic pressing: Microstructure stability and properties
No full textTwo fully dense nanocrystalline TiAl-based compacts, Ti-47.5Al-3Cr and Ti-48Al-2Nb-2Cr, were synthesized by hot isostatic pressing (HIP'ing) from mechanically alloyed (MA'd) powders. Microstructure evolution and phase transformations after MA'ing, HIP'ing, and following annealing were studied. Formation of amorphous phases was detected in both powders after 15 hour MA'ing. During HIP'ing, crystallization of the amorphous phases occurred and very fine equiaxed gamma-TiAl grains were formed. The grain size decreased when the temperature of HIP'ing was decreased, and it was 42 nm after HIP'ing at 725 °C. Grain growth occurred during annealing of the HIP'd alloys, which could be described by a single thermally activated process limited by a permanent pinning force. The activation energy of the grain growth was close to the activation energy for lattice diffusion of Ti in TiAl. Microhardness decreased with the annealing time and followed the Hall-Perch dependence on the grain size
Sinthesis of TiAl-Based Intermetallics with Nanocrystalline Structure by Mechanical Alloying and Hot Isostatic Pressing: Microstructure and Properties
No full textDifferential Acquisition of m-Sequences using Recursive Soft Sequential Estimation
No full textIn this contribution a novel sequential estimation method is proposed for the acquisition of -sequences. This sequential estimation method exploits the principle of iterative soft-in-soft-out (SISO) decoding for enhancing the acquisition performance, and that of differential pre-processing for the sake of achieving an enhanced acquisition performance, when communicating over various communication environments. Hence the advocated acquisition arrangement is referred to as the Differential Recursive Soft Sequential Estimation (DRSSE) acquisition scheme. The DRSSE acquisition scheme exhibits a low complexity, which is similar to that of an -sequence generator, while achieving an acquisition time that is linearly dependent on the number of stages in the -sequence generator. A low acquisition time is achieved with the advent of the property that the proposed DRSSE scheme is capable of determining the real-time reliabilities associated with the decision concerning a set of, say , consecutive chips. This set of consecutive chips constitutes the sufficient initial condition for enabling the local -sequence generator to produce a synchronized local despreading -sequence replica. Owing to these attractive characteristics, the DRSSE acquisition scheme constitutes a promising initial synchronization scheme for acquisition of long -sequences, when communicating over various propagation environments
∑_(l+m=k,l,m≥0) ((α+l-1)¦l) ((β+m-1)¦m)=((α+β+k-1)¦k) and its application to negative binomial distribution
No full textWe prove here the following equation: ∑_(l+m=k,l,m≥0) ((α+l-1)¦l) ((β+m-1)¦m)=((α+β+k-1)¦k) and give its application to prove the reproductive property of the negative binomial distribution.
These finite sum equation involving binomial coefficients and proof of the reproductive property are not known as far as the author knows.論文(Article)departmental bulletin pape
De Maiestate / Praeside M. Jacobo Thomasio, Moralis Philosoph. P. P., publice disputabit Johannes Dunte, R. L. Author & Respon: ad diem 9. Septembr. H L. Q. C.
No full textDE MAIESTATE / PRAESIDE M. JACOBO THOMASIO, MORALIS PHILOSOPH. P. P., PUBLICE DISPUTABIT JOHANNES DUNTE, R. L. AUTHOR & RESPON: AD DIEM 9. SEPTEMBR. H L. Q. C.
De Maiestate / Praeside M. Jacobo Thomasio, Moralis Philosoph. P. P., publice disputabit Johannes Dunte, R. L. Author & Respon: ad diem 9. Septembr. H L. Q. C. (1)
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Erratum to: Effect of moderate red wine intake on cardiac prognosis after recent acute myocardial infarction of subjects with Type 2 diabetes mellitus (Diabetic Medicine, (2006), 23, 9, (974-981), 10.1111/j.1464-5491.2006.01886.x)
No full textIn an article by Marfella et al, the author name C. Saron is incorrect and should be listed as C. Sardu. Therefore the correct author list is: R. Marfella, F. Cacciapuoti, M. Siniscalchi, F. C. Sasso, F. Marchese, F. Cinone, E. Musacchio, M. A. Marfella, L. Ruggiero, G. Chiorazzo, D. Liberti, G. Chiorazzo, G. F. Nicoletti, C. Sardu, F. D'Andrea, C. Ammendola, M. Verza and L. Coppola.In an article by Marfella et al, the author name C. Saron is incorrect and should be listed as C. Sardu. Therefore the correct author list is: R. Marfella, F. Cacciapuoti, M. Siniscalchi, F. C. Sasso, F. Marchese, F. Cinone, E. Musacchio, M. A. Marfella, L. Ruggiero, G. Chiorazzo, D. Liberti, G. Chiorazzo, G. F. Nicoletti, C. Sardu, F. D'Andrea, C. Ammendola, M. Verza and L. Coppola
Informetrics on M. N. Srinivas
No full textM. N. Srinivas, the well known sociologist is widely recognised as architect of modern Indian sociology and social anthropology. His publications have been analysed by year, domain, authorship pattern, channels of communication used. Keywords, etc. The results indicate that the papers published by him are of a nature that qualify him to be a 'role model' for the younger generations to emulate.
By the end of 1995, Srinivas had to his credit 144 papers which, included 33 broad papers in sociology and anthropology; 18 papers in social change; 28 papers in village studies; 12 papers on religion; 17 papers on caste and 36 papers of general popular interest. The periods 1958-61 and 1974-77, when Srinivas was 38-41 and 58-61 years old. were his most productive periods with highest publication activity
Silicon carbide nanorods and ceramics from wood
No full textJapanese cedar carbonized at 700degreesC was vacuum infiltrated with tetraethylorthosilicate (TEOS), and heated for 30 min at 1400, 1600 and 1800degreesC by electric pulse heating. The microstructure was investigated by X-ray diffraction and electron microscopy. Extra peaks in the XRD scans could be traced back to beta-SiC. Preliminary Auger analysis indicated an increase of the Si signal in pore walls. This was considered together with SEM images in agreement with the concept of a reaction layer covering the pore walls. Moreover, a large number of nanorods were present inside the pores. TEM analysis confirmed them to be SiC nanorods grown along the direction
The stability of IQ in people with low intellectual ability: an analysis of the literature
No full textA meta-analysis of the stability of low IQ (IQ 80) was performed on IQ tests that have been
commonly used—tests that were derived by D. Wechsler (1949, 1955, 1974, 1981, 1991, 1997)
and those based on the Binet scales (L. M. Terman, 1960; L. M. Terman & Merrill, 1972). Weighted-
mean stability coefficients of .77 and .78 were found for Verbal IQ (V IQ) and Performance IQ
(P IQ) on the Wechsler tests and .82 for Full-Scale IQ (FS IQ) on both Wechsler and Binet tests,
for a mean test–retest interval of 2.8 years. Although the majority of FS IQs changed by less than
6 points, 14% changed by 10 points or more. The author suggests that the results of IQ assessment
should be treated with more caution than previously thought
Downlink Space–Time Spreading Using Interference Rejection Codes
No full textIn this paper, the authors will investigate the performance of a loosely synchronized (LS) code-based space–time spreading (STS) scheme in comparison to that of classic Walsh code and pseudonoise code-based STS when communicating over dispersive Nakagami-m multipath channels. Closed-form formulas are derived for characterizing the bit-error-rate performance as a function of the number of resolvable paths L and the number of users K. Our numerical results suggest that the employment of LS code-based STS scheme is beneficial in a low-user-load and low-dispersion channel scenario, where a near-single-user performance can be achieved without a multiuser detector. Index Terms—Code-division multiple access (CDMA), Gaussian approximation, interference-free window (IFW), large area synchronized (LAS) codes, loosely synchronized (LS) codes, Nakagami-m fading
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