High power AlGaInP laser diodes with zinc-diffused window mirror structure

The technology of zinc-diffusion to improve catastrophic optical damage (COD) threshold of compressively strained GaInP/AlGaInP quantum well laser diodes has been introduced. After zinc-diffusion, about 20-μm-long region at each facet of laser diode has been formed to serve as the window of the lasing light. As a result, the COD threshold has been significantly improved due to the enlargement of bandgap by the zinc-diffusion induced quantum well intermixing, compared with that of the conventional non-window structure. 40-mW continuous wave output power with the fundamental transverse mode has been realized under room temperature for the 3.5-μm-wide ridge waveguide diode. The operation current is 84 mA and the slope efficiency is 0.74 W/A at 40 mW. The lasing wavelength is 656 nm.

Preliminary results of the updated LECR2 source-LECR2M

The Latest developed LECR2M (Lanzhou ECR No. 2 Modified) source is the updated one of LECR2 (Lanzhou ECR No. 2) source at IMP. It has been assembled on the low energy ion beam experimental platform to produce MCI beams for atomic physics and material physics experimental research. In our updating program, the structure of injection and extraction components has been modified to make the source structure more simple and effective. The hexapole magnet has also been replaced by a new hexapole magnet with higher radial field and larger inner diameter. With this updating, stronger magnetic field confinement of the ECR plasma is possible and better base vacuum condition is also achieved. LECR2M was designed to be operated at 14.5GHz. During the preliminary test, 1.3emA O6+ beam was extracted with the injected rf power of 1.1kW. The source has been used to deliver intense MCI beams for different experiments. After some discussion of the main features of this newly updated source, some of the typical commissioning test results of LECR2M will be presented.

Measurements of bremsstrahlung spectra on SECRAL

The axial emitted bremsstrahlung spectra were measured on SECRAL (Superconducting ECR ion source with Advanced design in Lanzhou) using an HPGe detector. The spectral temperature T-spe was obtained from the linear fit of the spectra in the semi-log present. The evolution of T-spe with microwave power and magnetic field configuration is investigated in this paper.

A compact proton source for space simulation

A compact proton beam source for space simulation has been developed. A compact structure was designed in order to meet the special requirements of miniaturization. Some particular means have been adopted for improving the proton portion and beam transmission at a long distance. The experimental results showed that 8mA/80keV proton beam can be successfully obtained from this source at about 700W input microwave power.

On a new genus and new species of xanthid crab (Crustacea, Decapoda, Brachyura, Xanthinae) from the South China Sea, with notes on the genus Liagore De Haan, 1833

A new genus and new species of xanthid crab, Ovatis simplex, is described from the South China Sea. The genus is closest to Liagore but can be distinguished by a suite of carapace and male gonopod characters. The systematic position of Liagore is also considered, and both genera, Liagore and Ovatis, are here referred to the subfamily Xanthinae. Comparisons with the allied genera, Paratergatis and Pulcratis, are also provided.

AUSTRO-GERMAN VIOLIN REPERTORIE FROM BAROQUE THROUGH ROMANTIC PERIOD

At the end of the sixteenth century, Germany had become one of the most active centers of early Baroque music, and therefore Austro-German music came to dominate Western music. An investigation of violin works written during this period reveals the ways in which Austro-German compositions are extraordinary contributions to the violin repertoire. This research warranted further study and performance of these works in order to determine what influence these composers had on the violin repertoire as a whole. For my dissertation recital project, I trace the history of works for violin focusing the violin concerto repertoire in particular. A genre which remained popular throughout the century, the nineteenth-century concerto served primarily as a vehicle for virtuosic display of the violin and piano as never before. For my research I studied and performed works selected from the Baroque through the Romantic period in three recorded recitals with collaborative pianists Ilya Sinaisky, Sun-ha Yun, and Seyon Lee at the Gildenhorn Recital Hall, Clarice Smith Performing Arts Center. I selected particularly prominent pieces which represent the work of significant composers from each period. The composers discussed include Johann Sebastian Bach (1685-1750), owing to the fact that his works are the culmination of the Baroque era during the first half of the eighteenth century; from the Classical period, Wolfgang Amadeus Mozart (1756-1791) all of whom emerged mixing German and Italian traditions into his own style, and Ludwig van Beethoven (1770-1827), the bridge composer between the Classical and the Romantic periods; Romantic composers, Franz Schubert (1979-1828), Johannes Brahms (1833-1897), Robert Schumann (1810-1856), Felix Mendelssohn (1809-1847), and Max Bruch (1838-1920), all who tended to mix Classic and Romantic elements. As a violinist, I learned that their own original sound, rich harmonies and unique expression made these works worthy of becoming masterpieces. I have relished the opportunity for musical and professional growth in exploring these substantial compositions.

THE PIANO MUSIC OF ROBERT SCHUMANN (1810-1856) AND JOHANNES BRAHMS (1833- 1897): A SURVEY OF CONCERTI, VARIATIONS, AND CHARACTER PIECES

Robert Schumann (1810-1856) and Johannes Brahms (1833-1897), in some ways Robert Schumann's artistic descendant, are the most important and representative German piano composers during the Romantic period. Schumann was already a mature and established musician in 1853 when he first met the young Brahms and recognized his talents, an encounter that had a long-lasting affect on the lives and careers of both men. After Schumann’s mental breakdown and death, Brahms maintained his admiration of Schumann’s music and preserved an intimate relationship with Clara Schumann. In spite of the personal and musical closeness of the two men, Schumann’s music is stylistically distinct from that of Brahms. Brahms followed traditions from Baroque and Classical music, and avoided using images and expressive titles in his music. Brahms extraordinarily intermingled earlier musical forms with multicolored tones of German Romanticism. In contrast, Schumann saw himself as a radical composer devoted to personal emotionalism and spontaneity. He favored programmatic titles for his character pieces and extra-musical references in his music. While developing their own musical styles as German Romantic composers, Schumann and Brahms both utilized the piano as a resourceful tool for self-realization and compositional development. To investigate and compare the main characteristics of Schumann and Brahms’s piano music, I looked at three genres. First, in the category of the piano concerto, I chose two major Romantic works, Schumann’s A minor concerto and Brahms’s B-flat major concerto. Second, for the category of piano variations I included two sets by Brahms because the variation framework was such an important vehicle for him to express his musical thoughts. Schumann’s unique motivic approach to variation is displayed vividly in his character-piece cycle Carnaval. Third, the category of the character piece, perhaps the favorite medium of Romantic expression at the piano, is shown by Schumann’s Papillons and Brahms’s sets of pieces Op.118 and Op.119. This performance dissertation consists of three recitals performed in the Gildenhorn Recital Hall at the University of Maryland, College Park. These recitals are documented on compact disc recordings that are housed within the University of Maryland Library System.

SELECTED CHARACTER PIECES OF FRÉDÉRIC CHOPIN (1810-1849), FRANZ LISZT (1811-1886) AND JOHANNES BRAHMS (1833-1897)

During the 19th century, Frédéric Chopin (1810-1849), Franz Liszt (1811- 1886), and Johannes Brahms (1833-1897) were among the most recognized composers of character pieces. Their compositions have been considered a significant milestone in piano literature. Frédéric Chopin (1810-1849) did not give descriptive titles to his character pieces. He grouped them into several genres such as Mazurkas, Polonaises. His Mazurkas and Polonaises are influenced by Polish dance music and inspired by the polish national idiom. Franz Liszt (1811-1886) was influenced in many ways by Chopin, and adopted Chopin’s lyricism, melodic style, and tempo rubato. However, Liszt frequently drew on non-musical subjects (e.g., art, literature) for inspiration. “Harmonies poétiques et religieuses” and “Années de pèlerinage” are especially representative of character pieces in which poetic and pictorial imagination are reflected. Johannes Brahms (1833-1897) was a conservative traditionalist, synthesizing Romantic expression and Classical tradition remarkably well. Like Chopin, Brahms avoided using programmatic titles for his works. The titles of Brahms’ short character pieces are often taken from traditional lyrical or dramatic genres such as ballade, rhapsody and scherzo. Because of his conservatism, Brahms was considered the main rival of Liszt in the Romantic Period. Brahms character pieces in his third period (e.g., Scherzo Op.4, Ballades of Op.10, and Rhapsodies of Op.79) are concise and focused. The form of Brahms’ character pieces is mostly simple ternary (ABA), and his style is introspective and lyrical. Through this recording project, I was able to get a better understanding of the styles of Chopin, Brahms and Liszt through their character pieces. This recording dissertation consists of two CDs recorded in the Dekelboum Concert Hall at the University of Maryland, College Park. These recordings are documented on compact disc recordings that are housed within the University of Maryland Library System.