Long distance fiber Bragg grating strain sensor interrogation using a high speed Raman-based Fourier domain mode-locked fiber laser with recycled residual Raman pump

We propose a novel fiber Bragg grating (FBG) sensor interrogation using a Raman-based Fourier-domain mode locking (FDML) fiber laser for a high speed and long distance measurement. A residual Raman pump after the generation of the Raman-based FDML fiber laser is recycled for secondary signal amplification in a 2-m erbium-doped fiber (EDF) to further enhance the output power. The chromatic dispersion is precisely controlled to suppress the phase noise in the FDML laser cavity, resulting in the improvement of an R-number of 1.43 mm/dB. After recycling residual pump, we achieve the 40-km round trip transmission of the sensing probe signal with a high scan rate of 30.8 kHz. With 205-mW residual pump power, the bandwidth and the maximum gain are measured to be more than 50 nm, 10.3 dB at 1550 nm, respectively. The sensitivity of the proposed Raman-based FDML fiber laser to strain is also measured, which are 0.81 pm/μstrain in the spectral domain and 0.19 ns/μstrain in the time domain, respectively

N-(2,5-Dimeth­oxy­phen­yl)-N′-(4-hy­droxy­pheneth­yl)urea

In the title compound, C17H20N2O4, the 2,5-dimeth­oxy­phenyl unit is almost planar, with an r.m.s. deviation of 0.015 Å. The dihedral angle between the 2,5-dimeth­oxy­phenyl ring and the urea plane is 20.95 (8)°. The H atoms of the urea NH groups are positioned syn to each other. The mol­ecular structure is stabilized by a short intra­molecular N—H⋯O hydrogen bond. In the crystal, inter­molecular N—H⋯O and O—H⋯O hydrogen bonds link the mol­ecules into a three-dimensional network

1-[3-(Hy­droxy­meth­yl)phen­yl]-3-phenyl­urea

In the title compound, C14H14N2O2, the dihedral angle between the benzene rings is 23.6 (1)°. The H atoms of the urea NH groups are positioned syn to each other. In the crystal, inter­molecular N—H⋯O and O—H⋯O hydrogen bonds link the mol­ecules into a three-dimensional network

Optimal Synthesis of Horizontally Aligned Single-Walled Carbon Nanotubes and Their Biofunctionalization for Biosensing Applications

As an influential candidate for highly sensitive biomolecule sensor, which can capture disease related biomolecules, carbon nanotube is useful material due to its unique properties. To adopt as a sensing platform, it is strongly needed to find optimal refined synthetic condition. In order to find the optimal synthetic conditions of horizontally aligned CNT, we performed quantity control of themixed gases of H-2 and CH4 injected. We successfully find that the formation of amorphous-like carbon was critically affected by some gas condition such as the flow rate of injected gases and ratios of gas mixture. Moreover, it should be noted that our horizontally aligned carbon nanotube array platform developed would offer another potential in developing nanoscale light source, where light emission results from electron-hole carrier recombinationope

Application of Virtual and Augmented Reality to the Field of Adult Education

This research reviews the extant literature and web resources on Virtual Reality (VR) and Augmented Reality (AR) to provide new insights and future direction of adult learning. Based on the review, we discuss implications for research and practice on the use of VR and AR in the field of Adult Education

3,4-Dihydroxy­phenyl 3,4,5-trimethoxy­benzoate

In the title compound, C16H16O7, the dihedral angle between the two benzene rings is 82.02 (7)°. The crystal structure is stabilized by inter­molecular O—H⋯O hydrogen bonds, which link the mol­ecules into a two-dimensional network

1-(3-Hy­droxy­phen­yl)-3-(3-meth­oxy­phenyl)thio­urea

In the title compound, C14H14N2O2S, the dihedral angles between the thio­urea group and the methoxyphenyl and hydroxyphenyl rings are 61.91 (4) and 76.90 (4)°, respectively. The benzene rings are twisted with respect to each other, making a dihedral angle of 71.03 (4)°. The H atoms of the thio­urea NH groups are positioned anti to each other. In the crystal, inter­molecular N—H⋯S, N—H⋯O and O—H⋯S hydrogen bonds link the mol­ecules into a three-dimensional network

Predictors of Academic Procrastination in Asian International College Students

This study examined the relationships among acculturative stress, coping styles, self-efficacy, English language proficiency, and various demographic characteristics as predictors of procrastination behavior in Asian International students (N = 255) studying in the United States. Results of multiple logistic regression indicated that a collective coping style, avoidant coping style, academic self-efficacy, and English language proficiency were the significant predictors of academic procrastination in non-Indian Asian international students. Implications for college student affairs professionals and researchers are addressed