高功率脉冲氙灯的动态PSpice模型研究

根据气体放电相关理论建立高功率脉冲氙灯仿真模型，阐述了放电回路设计的基本原理，采用建立的模型通过计算机对TIL及NIF装置进行仿真，给出了放电回路的仿真结果，与装置运行实际数据比较发现仿真模型及过程可靠，为高功率激光装置的电子计算机辅助设计和分析提供了一种新途径。

Fluorescence lifetime increasing with F- ions into ytterbium-doped germanium-lead-tellurite glasses

The effects of F- ions in a germanium-lead-tellurite glass system oil the spectral and potential laser properties of the Yb3+ are investigated. The absorption spectra, lifetimes, the emission cross-sections and the minimum pump intensities of the glass system with and without F- ions have been measured and calculated. The results show that the fluorescence lifetime and the minimum pump intensity of Yb3+ ions increase evidently, which indicates that germanium lead-oxyfluoride tellurite glass is a promising laser host matrix for high power generation. FT-IR spectra were used to analyse the effect of F- ions on OH- groups in this glass system. Analysis demonstrates that addition of fluoride removes the OH- groups and results in improvement of fluorescence lifetime of Yb3+.

LD抽运Yb:GSO实现1090nm低阈值激光运转

We report what we believe to be the first demonstration of laser operation with a novel laser material of Yb3(+) -doped Gd-2 SiO2 (Yb: GSO) pumped by a laser diode at 940 nm. We obtained a low lasing threshold of 1.27 kW/cm(2) with the center wavelength of 1090 nm, which is lower than the value of 1.53 kW/cm(2) predicted for Yb: YAG. The maximal output power of 360 mW was obtained with a 2% output, which corresponds to a slope efficiency up to 19%.

Teodulfo de Orléans y las Artes Liberales

Este trabajo lo hemos realizado dentro del proyecto de investigación «La Retórica en el medievo» concedido por la UPV (1/UPV 00106.130H-14809/2002).

History of Whaling and Estimated Kill of Right Whales, Balaena glacialis, in the Northeastern United States, 1620–1924

This study, part of a broader investigation of the history of exploitation of right whales, Balaena glacialis, in the western North Atlantic, emphasizes U.S. shore whaling from Maine to Delaware (from lat. 45°N to 38°30'N) in the period 1620–1924. Our broader study of the entire catch history is intended to provide an empirical basis for assessing past distribution and abundance of this whale population. Shore whaling may have begun at Cape Cod, Mass., in the 1620’s or 1630’s; it was certainly underway there by 1668. Right whale catches in New England waters peaked before 1725, and shore whaling at Cape Cod, Martha’s Vineyard, and Nantucket continued to decline through the rest of the 18th century. Right whales continued to be taken opportunistically in Massachusetts, however, until the early 20th century. They were hunted in Narragansett Bay, R.I., as early as 1662, and desultory whaling continued in Rhode Island until at least 1828. Shore whaling in Connecticut may have begun in the middle 1600’s, continuing there until at least 1718. Long Island shore whaling spanned the period 1650–1924. From its Dutch origins in the 1630’s, a persistent shore whaling enterprise developed in Delaware Bay and along the New Jersey shore. Although this activity was most profi table in New Jersey in the early 1700’s, it continued there until at least the 1820’s. Whaling in all areas of the northeastern United States was seasonal, with most catches in the winter and spring. Historically, right whales appear to have been essentially absent from coastal waters south of Maine during the summer and autumn. Based on documented references to specific whale kills, about 750–950 right whales were taken between Maine and Delaware, from 1620 to 1924. Using production statistics in British customs records, the estimated total secured catch of right whales in New England, New York, and Pennsylvania between 1696 and 1734 was 3,839 whales based on oil and 2,049 based on baleen. After adjusting these totals for hunting loss (loss-rate correction factor = 1.2), we estimate that 4,607 (oil) or 2,459 (baleen) right whales were removed from the stock in this region during the 38-year period 1696–1734. A cumulative catch estimate of the stock’s size in 1724 is 1,100–1,200. Although recent evidence of occurrence and movements suggests that right whales continue to use their traditional migratory corridor along the U.S. east coast, the catch history indicates that this stock was much larger in the 1600’s and early 1700’s than it is today. Right whale hunting in the eastern United States ended by the early 1900’s, and the species has been protected throughout the North Atlantic since the mid 1930’s. Among the possible reasons for the relatively slow stock recovery are: the very small number of whales that survived the whaling era to become founders, a decline in environmental carrying capacity, and, especially in recent decades, mortality from ship strikes and entanglement in fishing gear.

Competing for the Recreational Dollar: An Analysis of the California Commercial Passenger-Carrying Fishing Vessel Industry

California has a large and diverse marine recreational fishery. Anglers on commercial passenger-carrying fishing vessels (CPFV's) harvest a substantial proportion of California's marine recreational fisheries landings, accounting for about 40 percent and 16 percent of the total 1986 marine recreational catch in southern and northern California, respectively (NMFS, 1987). In 1986, 459,369 CPFV anglers landed some 2,835,021 fish in southern California, while 200,925 CPFV anglers landed 1,240, 100 fish in central and northern California.