An evaluation method for measuring SPL and mode shape of tire cavity resonance by using multi-microphone system

This paper presents an evaluation method for measuring the sound pressure level and mode shapes of tire cavity resonance by using a multi-microphone system. Two commercial tires were evaluated to compare abilities of noise suppression by means of this method in the range of the first resonance from 200 to 260 Hz. One tire was a special tire that suppresses tire cavity resonance with polyurethane foam mounted on the tire’s inner liner. The other tire was a normal tire with no polyurethane foam. The mode shape change from vertical to horizontal direction in both tires. However, the sound pressure level of the special tire was lower than the normal tire at all frequencies.     

Reinvestigation of the ν2 + 2ν3 subband in the overtone icosad of 12CH4 using cavity ring-down (CRD) spectroscopy of a supersonic jet expansion

We report a detailed reinvestigation of the ν₂?+?2ν₃ combination band of methane ¹²CH₄ centred at (7510.3378?±?0.003)?cm^?1 ((225.154263?±?0.0001)?THz) within the icosad of the overtone absorption. A new experimental setup is described, allowing us to carry out cw-laser cavity ring-down spectroscopy (cw-CRDS) at instrumental resolution in the MHz range in seeded supersonic jet expansions down to rotational temperature of 7?K compared to previous cw-CRDS measurements in our group achieving about 50?K in expansions of neat CH₄. We provide a careful re-analysis on the basis of our new experimental results for the Q and R branch transitions including data obtained between about 7 and 300?K under various conditions. We resolve previously observed discrepancies of assignments and are able to present a definitive assignment for lines involving angular momentum quantum numbers up to J?=?4. The analysis of relative intensities in spectra taken at rotational and effective translational temperatures between about 50?K and less than 10?K indicate conservation of nuclear spin symmetry upon supersonic jet expansion, in agreement with previous results using other techniques and covering other spectral ranges.     

In vitro monitoring of goat-blood glycemia with a microwave biosensor

We used an electromagnetic microwave cavity sensor for real time measurement of the glycemia in goat-blood for three animals. We could determine the concentration of d-glucose in blood in the range of 90–550 mg/dl at the resonance frequency near 4.76 GHz with a bandwidth of 300 MHz. The change in microwave reflection coefficient S₁₁ (due to the variation of d-glucose concentration in blood) was about 16.33 dB, 23.92 dB, 7.66 dB and resonance frequency shift was about 21.78 MHz, 36.29 MHz, 20.77 MHz, respectively, for the three different samples. The in vitro results show the measured signal-to-noise ratio of about 32 dB, and the minimum detectable signal level of about 0.025 dB/(mg/dl). The results clearly show the sensitivity and usefulness of this microwave sensor for these types of biological investigations. This proposed system provides a unique approach for real contactless glucose monitoring and, it may serve as a bloodless glucometer for the calibration of different glucose levels.     

The structure factor for liquid lead

Abstract

The structure factor for liquid lead at the temperatures 613 K, 643 K, 863 K and 1163 K are measured by neutron diffraction. Extensive comparisons to earlier measurements are made as well as comparisons to different hard-core models.     

Hybrid projection method for generalized mixed equilibrium problem and fixed point problem of infinite family of asymptotically quasi-?-nonexpansive mappings in Banach spaces

In this paper, we consider a hybrid projection method for finding a common element in the set of fixed points of a infinite family of asymptotically quasi-?-nonexpansive mappings and in the set of solutions of a generalized mixed equilibrium problem. Some strong convergence theorems of common elements are established in a uniformly smooth and strictly convex Banach space which has the Kadec-Klee property. The results presented in the paper improve and extend some recent results.     

Non-Poissonian statistics in an optical analog of quantum billiard with perfectly square boundaries

We study deviation from the Poissonian statistics of the frequency spacing distribution, appearing due to coupling of polarizational and transverse degrees of freedom in a perfectly square vertical cavity surface emitting laser. The deviation can be controlled by strength of the intracavity anisotropy and its alignment to the device boundaries.     

The isometric extension problem between unit spheres of two separable Banach spaces

In this article, we use some analytic and geometric characters of the smooth points in a sphere to study the isometric extension problem in the separable or reflexive real Banach spaces. We obtain that under some condition the answer to this problem is affirmative.     

Generation of sub‐terahertz repetition rates from a monolithic self‐mode‐locked laser coupled with an external Fabry‐Perot cavity

A novel scheme to multiply the repetition rate of a monolithic self‐mode‐locked laser for generating sub‐terahertz pulse sources is successfully demonstrated. A coated Yb:KGW crystal is designed to achieve a self‐mode‐locked operation at a repetition rate of 24 GHz with an average output power exceeding 1.0 W at a pump power of 4.8 W. A partially reflective mirror is utilized to combine with the output surface of the gain medium to constitute an external Fabry‐Perot cavity. It is theoretically and experimentally verified that adjusting the external cavity length to satisfy the commensurate condition can lead to the frequency spacing to be various order harmonics of the mode spacing of the monolithic cavity. The maximum pulse repetition rate of the laser output can be up to 216 GHz and the pulse duration is as short as 330 fs. More importantly, the overall characteristics of the first‐order temporal autocorrelation traces obtained by sequentially scanning the external cavity.length display an intriguing phenomenon of temporally fractional revivals, similar to the feature of spatial Talbot revivals.