Narrow Band Transmitting-Receiving Telescope System

This disclosure relates to a laser communication system which allows changing the direction of reception and transmission without external manipulation of the system container. The basic unit of the system is a narrow-band transmitting-receiving telescope apparatus which includes a rotating diffraction grating and an independently rotating stage with mounted combination of photodetector for reception and laser for transmission and a focusing system concentrating the beam reflected from the grating onto the photodetector of the combination or sending a beam from laser of the combination onto the grating. The selection of definite angles for signal transmission-reception is realized by corresponding rotation of grating and rotating stage to the proper angles. The apparatus is intended for spectrally selective transmitting or receiving of optical radiation. The main advantages of this apparatus are compactness and its ability to receive and/or transmit the light with definite wavelength

High Efficiency Volume Diffractive Elements in Photo-Thermo-Refractive Glass

Novel volume holographic elements were made from Bragg diffractive gratings in photo-thermo-refractive (PTR) glass with absolute diffraction efficiency ranging from greater than approximately 50% up to greater than approximately 93% and total losses below 5%. Both transmitting and reflecting volume diffractive elements were done from PTR glasses because of high spatial resolution enabling recording spatial frequencies up to 10000 mm.sup.-1. The use of such diffractive elements as angular selector, spatial filter, attenuator, switcher, modulator, beam splitter, beam sampler, beam deflectors controlled by positioning of grating matrix, by a small-angle master deflector or by spectral scanning, selector of particular wavelengths (notch filter, add/drop element, spectral shape former (gain equalizer), spectral sensor (wavelength meter/wavelocker), angular sensor (pointing locker), Bragg spectrometer (spectral analyzer), transversal and longitudinal mode selector in laser resonator were de

Process for Production of High Efficiency Volume Diffractive Elements in Photo-Thermo-Refractive Glass

A novel process is proposed for the volume diffractive element (Bragg grating) fabrication in photosensitive silicate glasses doped with silver, cerium, fluorine, and bromine. The process employs a photo-thermo-refractive (PTR) glass of high purity exposed to ultraviolet (UV) radiation of a He--Cd laser at 325 nm followed by thermal development at temperatures from 480.degree. C. to 580.degree. C., preferably at 520.degree. C., from several minutes to several hours. Absolute diffraction efficiency up to 95% was observed for 1 mm thick gratings. Maximum spatial frequency recorded in PTR glass was about of 10,000 mm.sup.-1. No decreasing of diffraction efficiency were detected at low spatial frequencies. Original glasses were transparent (absorption coefficient less than 1 cm.sup.-1) from 350 to 4100 nm. Induced losses in exposed and developed glass decreased from 0.3 to 0.03 cm.sup.-1 between 400 and 700 nm, respectively, and did not exceed 0.01-0.02 cm.sup.-1 in the infrared (IR) regi

Calculations of the rigidity and the strength of concrete filled steel deck diaphragms

Calculations of horizontal loads such as wind are required even for low-rise buildings. With stores number increasing their influence increases. The horizontal loads are perceived by the flooring discs. Steelreinforced concrete floors with profiled decking are most often used in steel frame buildings. Floor slabs and frame’s joint work is ensured by shear studs. The article discusses a shear studs’ stress determining method from horizontal load. There are different slab supporting variants: slap supported on two sides and along slab's perimeter. The goal was to determine shear stress in each flexible stop. The tasks were solved by calculating and by computing. Then the results were compared. Therefore, the resulting formula allows determining shear stresses not only in square slab but in rectangular ones too. Shear stress knowledge in the studs allows to determinate frames’ displacements by horizontal loads. Frame displaces relative to the floor slab due to studs shear and flexibility. The derived displacements determining formula takes into account shear deformations and anchor compliance in different directions. Herewithin the article, proposed displacements formula is not checked, but only the components determining a method is proposed

Education as the Basis for Developing Human Capital

Considering the theoretical, legal, and methodological foundations and using scientific methods have allowed us to reveal approaches for studying education values and establishing directions for human capital development. A set of research methods we used has contributed to substantiating the logical sequence and directions for human capital development. Differences in developing human capital are mainly due to the level of education. The research problem is to study education as a factor influencing the development of human capital. The paper aims to study the role of education in the development of human capital. The research object is human capital. The research subject is the impact of education on the development of human capital. The practical and scientific significance of the paper is in further studies on the influence of education on the development of human capital. Moreover, it is in overcoming the economic approach to this significant, complex, and multifaceted phenomenon

Demonstration of the temporal matter-wave Talbot effect for trapped matter waves

We demonstrate the temporal Talbot effect for trapped matter waves using ultracold atoms in an optical lattice. We investigate the phase evolution of an array of essentially non-interacting matter waves and observe matter-wave collapse and revival in the form of a Talbot interference pattern. By using long expansion times, we image momentum space with sub-recoil resolution, allowing us to observe fractional Talbot fringes up to 10th order.Comment: 17 pages, 7 figure

Azimuthal anisotropy at RHIC: the first and fourth harmonics

We report the first observations of the first harmonic (directed flow, v_1), and the fourth harmonic (v_4), in the azimuthal distribution of particles with respect to the reaction plane in Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). Both measurements were done taking advantage of the large elliptic flow (v_2) generated at RHIC. From the correlation of v_2 with v_1 it is determined that v_2 is positive, or {\it in-plane}. The integrated v_4 is about a factor of 10 smaller than v_2. For the sixth (v_6) and eighth (v_8) harmonics upper limits on the magnitudes are reported.Comment: 6 pages with 3 figures, as accepted for Phys. Rev. Letters The data tables are at http://www.star.bnl.gov/central/publications/pubDetail.php?id=3

Pion, kaon, proton and anti-proton transverse momentum distributions from p+p and d+Au collisions at sNN=200\sqrt{s_{NN}} = 200 GeV

Identified mid-rapidity particle spectra of $\pi^{\pm}$, $K^{\pm}$, and $p(\bar{p})$ from 200 GeV p+p and d+Au collisions are reported. A time-of-flight detector based on multi-gap resistive plate chamber technology is used for particle identification. The particle-species dependence of the Cronin effect is observed to be significantly smaller than that at lower energies. The ratio of the nuclear modification factor ($R_{dAu}$) between protons $(p+\bar{p})$ and charged hadrons ($h$) in the transverse momentum range $1.2<{p_{T}}<3.0$ GeV/c is measured to be $1.19\pm0.05$(stat)$\pm0.03$(syst) in minimum-bias collisions and shows little centrality dependence. The yield ratio of $(p+\bar{p})/h$ in minimum-bias d+Au collisions is found to be a factor of 2 lower than that in Au+Au collisions, indicating that the Cronin effect alone is not enough to account for the relative baryon enhancement observed in heavy ion collisions at RHIC.Comment: 6 pages, 4 figures, 1 table. We extended the pion spectra from transverse momentum 1.8 GeV/c to 3. GeV/

Mid-rapidity anti-proton to proton ratio from Au+Au collisions at sNN=130 \sqrt{s_{NN}} = 130 GeV

We report results on the ratio of mid-rapidity anti-proton to proton yields in Au+Au collisions at \rts = 130 GeV per nucleon pair as measured by the STAR experiment at RHIC. Within the rapidity and transverse momentum range of $|y|<0.5$ and 0.4 $<p_t<$ 1.0 GeV/$c$, the ratio is essentially independent of either transverse momentum or rapidity, with an average of $0.65\pm 0.01_{\rm (stat.)} \pm 0.07_{\rm (syst.)}$ for minimum bias collisions. Within errors, no strong centrality dependence is observed. The results indicate that at this RHIC energy, although the $p$-\pb pair production becomes important at mid-rapidity, a significant excess of baryons over anti-baryons is still present.Comment: 5 pages, 3 figures, accepted by Phys. Rev. Let

Transverse-momentum ptp_t correlations on (η,ϕ)(\eta,\phi) from mean-ptp_{t} fluctuations in Au-Au collisions at sNN=\sqrt{s_{NN}} = 200 GeV

We present first measurements of the pseudorapidity and azimuth $(\eta,\phi)$ bin-size dependence of event-wise mean transverse momentum $$ fluctuations for Au-Au collisions at $\sqrt{s_{NN}} = 200$ GeV. We invert that dependence to obtain $p_t$ autocorrelations on differences $(\eta_\Delta,\phi_\Delta)$ interpreted to represent velocity/temperature distributions on ($\eta,\phi$). The general form of the autocorrelations suggests that the basic correlation mechanism is parton fragmentation. The autocorrelations vary strongly with collision centrality, which suggests that fragmentation is strongly modified by a dissipative medium in the more central Au-Au collisions relative to peripheral or p-p collisions. \\Comment: 7 pages, 3 figure