Bounds for the natural frequencies of a plate subjected to a thermal gradient

Thermal gradient effects on vibrational frequencies of supported rectangular plat

Bounds for the eigenvalues of a simply- supported rectangular plate under a compressive stress varying linearly in the direction of loading

Upper bounds of eigenvalues of simply-supported rectangular plate using Rayleigh-Ritz metho

Simulations of a lattice model of two-headed linear amphiphiles: influence of amphiphile asymmetry

Using a 2D lattice model, we conduct Monte Carlo simulations of micellar aggregation of linear-chain amphiphiles having two solvophilic head groups. In the context of this simple model, we quantify how the amphiphile architecture influences the critical micelle concentration (CMC), with a particular focus on the role of the asymmetry of the amphiphile structure. Accordingly, we study all possible arrangements of the head groups along amphiphile chains of fixed length $N=12$ and 16 molecular units. This set of idealized amphiphile architectures approximates many cases of symmetric and asymmetric gemini surfactants, double-headed surfactants and boloform surfactants. Consistent with earlier results, we find that the number of spacer units $s$ separating the heads has a significant influence on the CMC, with the CMC increasing with $s$ for $s<N/2$. In comparison, the influence of the asymmetry of the chain architecture on the CMC is much weaker, as is also found experimentally.Comment: 30 pages, 17 fgure

Simulations of a lattice model of two-headed linear amphiphiles: influence of amphiphile asymmetry

Using a 2D lattice model, we conduct Monte Carlo simulations of micellar aggregation of linear-chain amphiphiles having two solvophilic head groups. In the context of this simple model, we quantify how the amphiphile architecture influences the critical micelle concentration (CMC), with a particular focus on the role of the asymmetry of the amphiphile structure. Accordingly, we study all possible arrangements of the head groups along amphiphile chains of fixed length $N=12$ and 16 molecular units. This set of idealized amphiphile architectures approximates many cases of symmetric and asymmetric gemini surfactants, double-headed surfactants and boloform surfactants. Consistent with earlier results, we find that the number of spacer units $s$ separating the heads has a significant influence on the CMC, with the CMC increasing with $s$ for $s<N/2$. In comparison, the influence of the asymmetry of the chain architecture on the CMC is much weaker, as is also found experimentally.Comment: 30 pages, 17 fgure

A Stimulated Raman Loss spectrometer for metrological studies of quadrupole lines of hydrogen isotopologues

We discuss layout and performance of a high-resolution Stimulated Raman Loss spectrometer that has been newly developed for accurate studies of spectral lineshapes and line center frequencies of hydrogen isotopologues and in general of Raman active transitions. Thanks to the frequency comb calibration of the detuning between pump and Stokes lasers and to an active alignment of the two beams, the frequency accuracy is well below 100 kHz. Over the vertical axis the spectrometer benefits from shot-noise limited detection, signal enhancement via multipass cell, active flattening of the spectral baseline and measurement times of few seconds over spectral spans larger than 10 GHz. Under these conditions an efficient averaging of Raman spectra is possible over long measurement times with minimal distortion of spectral lineshapes. By changing the pump laser, transitions can be covered in a very broad frequency span, from 50 to 5000 $\mathrm{cm^{-1}}$, including both vibrational and rotational bands. The spectrometer has been developed for studies of fundamental and collisional physics of hydrogen isotopologues and has been recently applied to the metrology of the Q(1) 1-0 line of $\mathrm{H_2}$

A stimulated Raman loss spectrometer for metrological studies of quadrupole lines of hydrogen isotopologues

We discuss layout and performance of a high-resolution Stimulated Raman Loss spectrometer that has been newly developed for accurate studies of spectral lineshapes and line centre frequencies of hydrogen isotopologues and in general of Raman active transitions. Thanks to the frequency comb calibration of the detuning between pump and Stokes lasers and to an active alignment of the two beams, the frequency accuracy is at a level of 50 kHz. Over the vertical axis the spectrometer benefits from shot-noise limited detection, signal enhancement via multipass cell, active flattening of the spectral baseline and measurement times of few seconds over spectral spans larger than 10 GHz. Under these conditions an efficient averaging of Raman spectra is possible over long measurement times with minimal distortion of spectral lineshapes. By changing the pump laser, transitions can be covered in a very broad frequency span, from 50 to 5000 cm−1, including both vibrational and rotational bands. The spectrometer has been developed for studies of fundamental and collisional physics of hydrogen isotopologues and has been recently applied to the metrology of the Q(1) 1–0 line of H2

Correlated photon-pair generation in a periodically poled MgO doped stoichiometric lithium tantalate reverse proton exchanged waveguide

We demonstrate photon-pair generation in a reverse proton exchanged waveguide fabricated on a periodically poled magnesium doped stoichiometric lithium tantalate substrate. Detected pairs are generated via a cascaded second order nonlinear process where a pump laser at wavelength of 1.55 $\mu$m is first doubled in frequency by second harmonic generation and subsequently downconverted around the same spectral region. Pairs are detected at a rate of 42 per second with a coincidence to accidental ratio of 0.7. This cascaded pair generation process is similar to four-wave-mixing where two pump photons annihilate and create a correlated photon pair

Antenatal syphilis serology in pregnant women and follow-up of their infants in northern Italy

ABSTRACTPositive syphilis serology was noted in 119 (0.49%) of the 24 053 pregnant women delivering at St Orsola Hospital in Bologna, Italy, from November 2000 through July 2007. Six presumptive cases of congenital syphilis with IgM western blot positive results were found. Two infants had a positive cerebrospinal fluid (CSF) Venereal Disease Research Laboratory test result (one also had a positive CSF PCR result), another presented long-bone lesions, and the remaining three were preterm. These observations confirmed that antenatal syphilis screening facilitates treatment during pregnancy and offsets vertical transmission; moreover, the use of IgM western blot and careful CSF examination allowed the identification and treatment of high-risk newborns

Comb-assisted spectroscopy of CO2 absorption profiles in the near- and mid-infrared regions

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