924 resultados para Teorema de Mayer-Vietoris
Resumo:
The algebraic expressions for the anharmonic contributions to the Debye-Waller factor up to 0(A ) and 0 L% ) £ where ^ is the scattering wave-vector] have been derived in a form suitable for cubic metals with small ion cores where the interatomic potential extends to many neighbours. This has been achieved in terms of various wave-vector dependent tensors, following the work of Shukla and Taylor (1974) on the cubic anharmonic Helmholtz free energy. The contribution to the various wave-vector dependent tensors from the coulomb and the electron-ion terms in the interatomic metallic potential has been obtained by the Ewald procedure. All the restricted multiple whole B r i l l o u i n zone (B.Z.) sums are reduced to single whole B.Z. sums by using the plane wave representation of the delta function. These single whole B.Z. sums are further reduced to the •%?? portion of the B.Z. following Shukla and Wilk (1974) and Shukla and Taylor (1974). Numerical calculations have been performed for sodium where the Born-Mayer term in the interatomic potential has been neglected because i t is small £ Vosko (1964)3 • *n o^er to compare our calculated results with the experimental results of Dawton (1937), we have also calculated the r a t io of the intensities at different temperatures for the lowest five reflections (110), (200), (220), (310) and (400) . Our calculated quasi-harmonic results agree reasonably well with the experimental results at temperatures (T) of the order of the Debye temperature ( 0 ). For T » © ^ 9 our calculated anharmonic results are found to be in good agreement with the experimental results.The anomalous terms in the Debye-Waller factor are found not to be negligible for certain reflections even for T ^ ©^ . At temperature T yy Op 9 where the temperature is of the order of the melting temperature (Xm) » "the anomalous terms are found to be important almost for all the f i ve reflections.
Resumo:
In 1948, The St. Catharines Civic Orchestra was founded by Jan Wolanek who was also the first conductor. Initially, this was a community orchestra and in 1963 its governing body assumed the name St. Catharines Symphony Association. In 1978 the name was again changed to The Niagara Symphony Association to reflect regional responsibilities. Wally Laughton was named Assistant Conductor in 1952/53. R.C. Clarke took over the orchestra for an interim period after Wolanek left in 1957. In 1958 Leonard Pearlman became the Music Director. It was under his direction that the Niagara Symphony Chorus came into existence in 1963. Milton Barnes succeeded Pearlman in 1964 and he was responsible for directing the symphony’s first opera production. He also made a concerted effort to attract younger people to symphonic music. In 1972 Leonard Atherton became the Music Director. He started the Cantata Choir and the Madrigal Singers. It was under his tenure that the orchestra became professional. When Atherton left in 1980, there were three seasons of guest conductors, the most notable of these conductors was Uri Mayer. In 1981 James Vincent Fusco was appointed as composer in residence and in 1983 Ermanno Florio became the Music Director. He retained this position until 1995 when Michael Reason took over. Daniel Swift was appointed as Music Director and Conductor in 1999 and the Niagara Symphony Orchestra became the orchestr in residence at Brock University. Laura Thomas was appointed as Associate Conductor 1n 2004. Daniel Swift’s resignation in 2008 began a search for a new Music Director. Bradley Thachuck was appointed as Music Director Designate and Principal Conductor in 2010. The orchestra is a fully professional, charitable institution with 52 members.The orchestra has also been led by Victor Feldbrill and Howard Cable. A junior symphony was first formed under Leonard Pearlman in 1960/61, but it wasn’t until 1965 that The St. Catharines Youth Orchestra was founded. The orchestra has consistently been an award winner in music festivals. The musicians range in age from 12 to 18 years. The highlight of the 1973-74 season was the orchestra’s participation in the first Canadian Festival of Youth Orchestras at The Banff School of Fine Arts. The St. Catharines Youth Orchestra has evolved from the St. Catharines School String and Brass Ensembles to a full scale symphony under the direction of conductor Paul van Dongen. In 1974 the Symphony House music program came into existence. It was 1976 when Richard Grymonpre was hired as the principal violinist of the St. Catharines Symphony Orchestra and conductor of the St. Catharines Youth Orchestra. Tak Ng Lai took over the position as conductor in 1978. Laura Thomas is currently the Music Director of The Niagara Youth Orchestra. Source: Niagara Symphony, Orchestra in Residence, Brock University website and notes from Niagara Symphony files
Resumo:
UANL
Resumo:
UANL
