Tunable Raman Soliton Source Using Mode-Locked Tm–Ho Fiber Laser

We report a femtosecond pulse source that uses a mode-locked Tm-Ho oscillator and a self-frequency shift of Raman solitons in Tm-Ho power amplifier. The master oscillator mode-locked by an antimonide-based saturable absorber mirror produces 750-fs transform-limited soliton pulses over the tuning range from 1912 to 1972 nm. The soliton self-frequency shift in the amplifier resulted in transform-limited pulses with the wavelength adjusted by varying the amplifier pump power. We obtain ~150-fs soliton pulses at the wavelength of 2150 nm with average power up to 230 mW corresponding to the peak power of 27 kW. The efficiency of Raman conversion ranges from 47% to 62% over the tuning range     

Electronically Tunable Yb-Doped Mode-Locked Fiber Laser

We report a passively mode-locked picosecond Yb-doped fiber laser that is electronically tunable over 30 nm around 1.04 m. The fiber laser with a tuning accuracy of better than 0.1 nm and a tuning time of as fast as 15 s employs an acoustooptic filter. The semiconductor saturable absorber mirror used in a cavity with a frequency-shifted feedback improves noticeably the mode-locked operation.     

Alcohol use and intimate partner violence perpetration among college students: Assessing the temporal association using electronic diary technology.

Objectives: The primary goals of this study were to assess the temporal relationship between alcohol use and intimate partner violence (IPV) perpetration using state-of-the-art electronic diary assessment methods and to examine the extent to which distal factors (e.g., sex, psychopathology, relationship satisfaction) moderated that association. Method: Participants were 184 male and female college students in dating relationships who used a handheld computer to answer daily questions about alcohol use and IPV every day for 2 months. Results: Based on a total of 7,775 daily electronic diary reports, results showed that the odds of perpetrating psychological and physical aggression were 2.19 and 3.64 times greater, respectively, on drinking days relative to nondrinking days. Men evidenced 7.03 greater odds of engaging in psychological aggression on drinking days, whereas women had only 1.60 greater odds of engaging in psychological aggression on drinking relative to nondrinking days. Conclusion: Findings suggest the need to provide intervention early in dating relationships to reduce alcohol use to reduce the risk of IPV. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Mode-Locked Bi-Doped All-Fiber Laser With Chirped Fiber Bragg Grating

We demonstrate a bi-doped fiber laser with dispersion compensation provided by a linearly chirped fiber Bragg grating. Reliable self-starting mode-locking was achieved by using an InGaAsN semiconductor saturable absorber mirror. The all-fiber laser generated short optical pulses with a duration of 1.9 ps at ~ 1165 nm. The large anomalous dispersion of the fiber grating ensured operation in the soliton pulse regime. This in turn enabled us to increase the repetition rate of the output pulse train up to 100.6 MHz via harmonic mode-locking.     

Determination of the percentage of homopolymer component in Ziegler/Natta catalyst linear low-density polyethylene resins using high-temperature cell Fourier transform infrared and partial least squares quantitative analysis technique

A new method for the determination of the percentage of homopolymer component, using high-temperature cell Fourier transform infrared (FT-IR) by partial least squares (PLS) quantitative analysis technique, was developed and applied to Ziegler Natta linear low-density polyethylene (LLDPE). The method is based on the IR spectrum changes between the 730 cm(-1) band and 720 cm(-1) band at the temperature of 110 degrees C, which is near the melting point of the polyethylene. The HD % (the percentage of high-density component, i.e., the percentage of homopolymer component) results obtained by CTREF (CRYSTAF in TREF mode) technique are used as the input data together with the respective FT-IR spectra for PLS analyses to establish a calibration curve. The PLS quality is characterized by a correlation coefficient of 0.997 (cross-validation) using four factors and a root mean square error of calibration (RMSEC) of 0.772. The HD% of the unknown can then be predicted by the PLS software from the unknown FT-IR spectrum. A control resin was tested seven times by CTREF and FT-IR. The HD% of the control resin was 28.59+/-0.88% by CTREF and 29.05+/-2.37% by FT-IR. It was found that the method was applicable for the same comonomer type of LLDPE within a melt index range and density.