Low-timing-jitter, stretched-pulse passively mode-locked fiber laser with tunable repetition rate and high operation stability

We design a low-timing-jitter, repetition-rate-tunable, stretched-pulse passively mode-locked fiber laser by using a nonlinear amplifying loop mirror (NALM), a semiconductor saturable absorber mirror (SESAM), and a tunable optical delay line in the laser configuration. Low-timing-jitter optical pulses are stably produced when a SESAM and a 0.16 m dispersion compensation fiber are employed in the laser cavity. By inserting a tunable optical delay line between NALM and SESAM, the variable repetition-rate operation of a self-starting, passively mode-locked fiber laser is successfully demonstrated over a range from 49.65 to 50.47 MHz. The experimental results show that the newly designed fiber laser can maintain the mode locking at the pumping power of 160 mW to stably generate periodic optical pulses with width less than 170 fs and timing jitter lower than 75 fs in the 1.55 mu m wavelength region, when the fundamental repetition rate of the laser is continuously tuned between 49.65 and 50.47 MHz. Moreover, this fiber laser has a feature of turn-key operation with high repeatability of its fundamental repetition rate in practice.

Studies of timing for a TOF counter at external target facility

Timing and amplitude properties of a prototype scintillator TOF counter at an external target facility are studied with a cosmic rays test. The dependence of signal pulse height and time resolution on the coordinate along the scintillator TOF counter is investigated with two different discriminators. A time resolution of 165 ps can be achieved at the center of the counter with a constant fraction discriminator. Time resolution better than 150 ps is obtained at the center with a leading edge discriminator af...

Timing system of HIRFL-CSR

The national science project HIRFL-CSR has recently been officially accepted. As a cyclotron and synchotron complex, it puts some particularly high demands on the control system. There are hundreds of pieces of equipment that need to be synchronized. An integrated timing control system is built to meet these demands. The output rate and the accuracy of the controller are 16 bit/mu s. The accuracy of the time delay reaches 40 ns. The timing control system is based on a typical event distribution system, which adopts the new event generation and the distribution scheme. The scheme of the tuning control system with innovation points, the architecture and the implemented method are presented in the paper.

Eutrophication process recorded in dinoflagellate cyst assemblages — a case of Yokohama Port, Tokyo Bay, Japan

To investigate temporal changes of water quality, a role of dinoflagellate cysts preserved in surface sediments was examined in Yokohama Port in Tokyo Bay, Japan. Two cores were collected, and sedimentation rates and ages of both were dated as approximately 1900 years or slightly older on the basis of 210Pb and 137Cs concentrations. The temporal change in dinoflagellate cyst assemblages in the two cores reflects eutrophication in Yokohama Port in the 1960s. Abrupt increases in the cysts of Gyrodinium instriatum cysts strongly suggests that a red tide was caused by this species around 1985. Dinoflagellate cyst assemblages in surface sediments appear to be good biomarkers of changes in the water quality of enclosed seas.

A comprehensive investigation of an offshore active fault in the Western Sagami Bay, central Japan

Offshore active faults, especially those in the deep sea, are very difficult to study because of the water and sedimentary cover. To characterize the nature and geometry of offshore active faults, a combination of methods must be employed. Generally, seismic profiling is used to map these faults, but often only fault-related folds rather than fracture planes are imaged. Multi-beam swath bathymetry provides information on the structure and growth history of a fault because movements of an active fault are reflected in the bottom morphology. Submersible and deep-tow surveys allow direct observations of deformations on the seafloor (including fracture zones and microstructures). In the deep sea, linearly aligned cold seep communities provide indirect evidence for active faults and the spatial migration of their activities. The Western Sagami Bay fault (WSBF) in the western Sagami Bay off central Japan is an active fault that has been studied in detail using the above methods. The bottom morphology, fractured breccias directly observed and photographed, seismic profiles, as well as distribution and migration of cold seep communities provide evidence for the nature and geometry of the fault. Focal mechanism solutions of selected earthquakes in the western Sagami Bay during the period from 1900 to 1995 show that the maximum compression trends NW-SE and the minimum stress axis strikes NE-SW, a stress pattern indicating a left-lateral strike-slip fault.

Effects of winds, tides and storm surges on ocean surface waves in the Sea of Japan

Ocean surface waves are strongly forced by high wind conditions associated with winter storms in the Sea of Japan. They are also modulated by tides and storm surges. The effects of the variability in surface wind forcing, tides and storm surges on the waves are investigated using a wave model, a high-resolution atmospheric mesoscale model and a hydrodynamic ocean circulation model. Five month-long wave model simulations are inducted to examine the sensitivity of ocean waves to various wind forcing fields, tides and storm surges during January 1997. Compared with observed mean wave parameters, results indicate that the high frequency variability in the surface wind filed has very great effect on wave simulation. Tides and storm surges have a significant impact on the waves in nearshores of the Tsushima-kaihyo, but not for other regions in the Sea of Japan. High spatial and temporal resolution and good quality surface wind products will be crucial for the prediction of surface waves in the JES and other marginal seas, especially near the coastal regions.

21世纪企业的主要模式──敏捷制造企业

２０世纪９０年代以后，由于科学技术的迅猛发展，知识─技术─产品的周期日益缩短，如何加速开发质优价廉的新产品就成为企业竞争的核心内容。２１世纪即将到来，世界无疑将沿着２０世纪的道路继续向前发展，它的趋势是：新产品开发速度日益加快、产品生命周期不断缩短、生产批量越来越小、市场竞争日趋激烈；加上环太平洋地区的兴起，有能力参与这场竞争的企业不断增多。这一切虽给企业带来了机遇，但也给企业造成了严酷的生存环境。为了适应这种环境，１９９１年美国在总结日本、德国和本国经验的基础上，提出把现有企业改造成敏捷制造企业（ＡｇｉｌｅＭａｎｕｆａｃｔｕｒｉｎｇＥｎｔｅｒｐｒｉｓｅ）的模式，并认为这是奠定美国２１世纪经济霸主地位的战略举措。敏捷制造企业是从客观经济发展的实践中总结出来的。我国如何改造企业并和世界经济接轨，敏捷制造企业给我们提出了值得高度重视的发展方向，本文对此作了较为详尽的论述。

What influences the timing of the introduction of solid food to infants?

The aim of the present study was to assess the factors which may influence the timing of the introduction of solid food to infants. The design was a prospective cohort study by interview and postal questionnaire. Primiparous women (n 541) aged between 16 and 40 years were approached in the Forth Park Maternity Hospital, Fife, Scotland. Of these, 526 women agreed to participate and seventy-eight were used as subjects in the pilot study. At 12 weeks we interviewed 338 women of the study sample. The postal questionnaire was returned by 286 of 448 volunteers. At 12 weeks 133 of 338 mothers said that they had introduced solids. Those that said that they had introduced solids early (<12 weeks) were compared with those who had introduced solids late (>12 weeks) by bivariate and multiple regression analysis. Psychosocial factors influencing the decision were measured with the main outcome measure being the time of introduction of solid food. The early introduction of solids was found to be associated with: the opinions of the infant's maternal grandmother; living in a deprived area; personal disagreement with the advice to wait until the baby was 4 months; lack of encouragement from friends to wait until the baby was 4 months; being in receipt of free samples of manufactured food. Answers to open-ended questions indicated that the early introduction appeared to be influenced by the mothers’ perceptions of the baby's needs. Some of the factors influencing a woman's decision to introduce solids are amenable to change, and these could be targeted in educational interventions.

Fractional versus decimal pricing: Evidence from the UK Long Gilt futures market

ap Gwilym, Owain, McManus, Ian, and Thomas, Stephen, 'Fractional versus decimal pricing: Evidence from the UK Long Gilt futures market', Journal of Futures Markets (2005) 25(5) pp.419-442 RAE2008

International market selection : Measuring actions instead of intentions

Alexander, N.; Rhodes, M.; and Myers, H. (2007). International market selection: measuring actions instead of intentions. Journal of Services Marketing. 21(6), pp.424-434 RAE2008