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Optical and Quantum Electronics - A high-sensitive refractive index (RI) measuring method is proposed through the combined use of elliptical core photonic crystal fiber (PCF) and Sagnac... 相似文献
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Fariba Jam 《Tetrahedron》2007,63(39):9881-9889
A general and efficient method for the synthesis of spiro-2,5-diketopiperazines (spiro-DKPs) is described. Cyclization of Boc-protected dipeptides containing spiro-amino acids by microwave assisted heating in water furnished the corresponding spiro-DKPs. The spiro-amino acids were prepared by combining stereoselective alkylation reactions using the Schöllkopf methodology for amino acid construction with Grubbs ring-closing metathesis (RCM) methodology using ruthenium complexes. The RCM reactions and all subsequent transformations to the spiro-DKPs were run with microwave assisted heating, resulting in high yields and short reaction times for all steps. 相似文献
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M. Englert J. Kowalski F. Mayer R. Neumann S. Noehte R. Schwarzwald H. Suhr K. Winkler G. zu Putlitz Ch. J. Bordé S. Avrillier A. van Lerberghe Ch. Salomon Ch. Breant D. Bassi G. Scoles J. Helmcke D. Zevgolis B. Ü. Yen W. Gawlik F. Träger M. Vollmer E. Gustafson R. L. Byer J. H. M. Neijzen A. Donszelmann G. Leuchs J. Rerf H. Walther M. Inguscio A. Moretti F. Strumia J. L. Picqué J. L. Le Gouët F. Wuilleumier J. M. Bizau P. Dhez P. Koch D. Ederer O. Poulsen U. Nielsen N. I. Winstrup P. S. Ramanujam J. V. James X. Tang C. C. Wang 《Applied physics. B, Lasers and optics》1982,28(2-3):81-91
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SB349 is the first 32 × 32 CTIA readout multiplexer specifically designed for far-IR photodetectors and is operable at cryogenic temperatures at least as low as 1.7 K. Four of these readouts can be butted together to form a 64 × 64 mosaic array. The array is multiplexed into eight parallel outputs and features eight selectable gain settings to accommodate various background levels, auto-zero for better input uniformity, and sample-and-hold circuitry. A special, 2-micron cryo-CMOS process was adopted to prevent freeze out and ensure low noise and proper operation at deep cryogenic temperatures. The read noise of the bare device at 4.2 K and under nominal sampling conditions was measured to be about 250e? for the 106fF signal capacitor with the well capacity of 400ke?. Hybridized to a typical germanium detector, the array should achieve NEP levels in the low 10–18 W/√Hz. An overview of the design and the latest results of the test and characterization of this device are reported in this paper. 相似文献