Journal articles on the topic 'Analog beams'
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Aldalbahi, Adel. "Multi-Backup Beams for Instantaneous Link Recovery in mmWave Communications." Electronics 8, no. 10 (October 10, 2019): 1145. http://dx.doi.org/10.3390/electronics8101145.
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In this paper, a novel link recover scheme is proposed for standalone (SA) millimeter wave communications. Once the main beam between the base station (BS) and the mobile station (MS) is blocked, then a bundle-beam is radiated that covers the spatial direction of the blocked beam. These beams are generated from an analog beamformer design that is composed of parallel adjacent antenna arrays to radiate multiple simultaneous beams, thus creating an analog beamformer of multiple beams. The proposed recovery scheme features instantaneous recovery times, without the need for beam scanning to search for alternative beam directions. Hence, the scheme features reduced recovery times and latencies, as opposed to existing methods.
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Sireesha, Polireddi. "Channel Estimation for Massive MIMO Systems." International Journal for Research in Applied Science and Engineering Technology 10, no. 1 (January 31, 2022): 137–38. http://dx.doi.org/10.22214/ijraset.2022.39775.
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Abstract: In MIMO millimeter-wave (mmWave) systems, while the hybrid digital/analog precoding structure provides the ability to increase the reach rate, it also faces the challenge of reducing the channel time limit due to the large number of horns on both sides of the Tx / Rx. . In this paper, channel measurement is done by searching with multiple beams, and a new hierarchical multi-beam search system is proposed, using a pre-designed analog codebook. Performance tests show that, compared to a highperformance system, the proposed system not only achieves a high level of success in getting multiple beams under normal system settings but also significantly reduces channel estimation time Keywords: Massive MIMO, Channel Estimation, precoding
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Hampele, M., A. Kratzer, K. Maier, J. Major, K. H. Münch, and Th Pfiz. "Analog integrating detection technique for pulsed muon beams." Hyperfine Interactions 87, no. 1 (December 1994): 1043–47. http://dx.doi.org/10.1007/bf02068502.
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El Mettiti, Abderrahmane, and Mohammed Oumsis. "A Stacked Autoencoder and Multilayer Perceptrons for mmWave Beamforming Prediction." Ingénierie des systèmes d information 27, no. 3 (June 30, 2022): 479–85. http://dx.doi.org/10.18280/isi.270315.
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The millimeter-wave frequencies planned for 6G systems present challenges for channel modeling. At these frequencies, surface roughness affects wave propagation and causes severe attenuation of millimeter-wave (mmWave) signals. In general, beamforming techniques compensate for this problem. Analog beamforming has some major advantages over its counterpart, digital beamforming, because it uses low-cost phase shifters for massive MIMO systems compared to digital beamforming that provides more accurate and faster results in determining user signals. However, digital beamforming suffers from high complexity and expensive design, making it unsuitable for mmWave systems. The techniques proposed so far for analog beamforming are often challenging in practice. In this work, we have proposed a deep learning model for analog beams training that helps predict the optimal beam vector. Our model uses an available dataset of 18 base stations, over 1 million users, 60 GHz frequency. The training process first applies a stacked autoencoder to extract the features from the training datasets, and then uses a multilayer perceptron (MLP) to train and predict the optimal beams. Then, the results are evaluated by computing the mean squared error between the expected and predicted beams using the test set. The results show high efficiency compared to the benchmark method, which uses only the MLP for the training process.
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Wang, Xin Wu, and Yan Zhao Li. "Experimental Study on Anti-Impact Properties of Prestressed Concrete Beams." Key Engineering Materials 400-402 (October 2008): 789–94. http://dx.doi.org/10.4028/www.scientific.net/kem.400-402.789.
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The dynamic displacement ductility and ultimate load-carrying capability of three partially prestressed concrete (PPC) and unbonded beams, has been experimentally investigated by applying impact load to their middle with falling hammers. The typical measurement wave curves are described. Influences of a falling hammer’s gravitational potential energy on the dynamic properties of the PPC beam are analyzed. Based on the analog simulation theory, the impact-load carrying capability of the actual unbonded PPC beam with span 12 m is gained. Results indicate that the unbonded PPC beams have favorable performance of anti-impact properties fragile destruction will not happen, and the unbonded PPC beams can be used in wide-span underground structures.
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Li, Jianguo, Neng Ye, Siqi Ma, Xiangyuan Bu, and Jianping An. "Multi-User Hybrid Beamforming Design for Physical Layer Secured mmWave LOS Communications." Electronics 10, no. 21 (October 28, 2021): 2635. http://dx.doi.org/10.3390/electronics10212635.
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This paper proposes a hybrid beamforming design algorithm for a multi-user physical layer security modulation technique. The hybrid beamforming scheme is used in the base station to generate multi-beams according to the direction angle of the target users. The base station first uses a secure analog beamforming scheme to generate analog beams in multiple desired directions, then uses minimum mean square error (MMSE) to design the digital beamforming matrix to eliminate inter-beam interference. Due to randomly selecting a subset of antennas to transmit signals at the symbol rate, the base station transmits the defined constellation to the target users and projects the randomized constellation in the other angles. In addition, the superposition of signals is affected by a randomly selected antennas subset, resulting in higher sidelobe energy. However, due to the integer optimization target, the optimization problem of antenna subsets is non-trivial. Therefore, this paper proposes a cross-entropy iteration method to choose the optimal antenna combination to reduce the sidelobe energy. The simulation shows that the proposed method in this paper has about 10 dB lower sidelobe energy than the random selection method. Besides, the eavesdropper’s symbol error rate of QPSK is always 0.75, while the multi-target users meet the quality of service requirements.
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Khammari, Hedi, Irfan Ahmed, Ghulam Bhatti, and Masoud Alajmi. "Spatio-Radio Resource Management and Hybrid Beamforming for Limited Feedback Massive MIMO Systems." Electronics 8, no. 10 (September 20, 2019): 1061. http://dx.doi.org/10.3390/electronics8101061.
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In this paper, a joint spatio–radio frequency resource allocation and hybrid beamforming scheme for the massive multiple-input multiple-output (MIMO) systems is proposed. We consider limited feedback two-stage hybrid beamformimg for decomposing the precoding matrix at the base-station. To reduce the channel state information (CSI) feedback of massive MIMO, we utilize the channel covariance-based RF precoding and beam selection. This beam selection process minimizes the inter-group interference. The regularized block diagonalization can mitigate the inter-group interference, but requires substantial overhead feedback. We use channel covariance-based eigenmodes and discrete Fourier transforms (DFT) to reduce the feedback overhead and design a simplified analog precoder. The columns of the analog beamforming matrix are selected based on the users’ grouping performed by the K-mean unsupervised machine learning algorithm. The digital precoder is designed with joint optimization of intra-group user utility function. It has been shown that more than 50 % feedback overhead is reduced by the eigenmodes-based analog precoder design. The joint beams, users scheduling and limited feedbacK-based hybrid precoding increases the sum-rate by 27 . 6 % compared to the sum-rate of one-group case, and reduce the feedback overhead by 62 . 5 % compared to the full CSI feedback.
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Su, Xiangyu, Jing Chen, Yan Liu, Xufeng Sun, Gong Meng, and Haida Wang. "Experimental study on flexural behavior of box floors with orthogonal rib beams made of poplar laminated veneer lumber." BioResources 17, no. 4 (September 8, 2022): 6019–35. http://dx.doi.org/10.15376/biores.17.4.6019-6035.
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This study examined the flexural behavior of the poplar laminated veneer lumber (LVL) box floor with orthogonal rib beams. Four 3.6 m × 4.8 m box floor samples made of poplar LVL orthogonal rib beams and oriented strand board (OSB) plates were tested under vertical uniform loading, from which the bearing capacity, stiffness, and failure characteristics were analyzed. There was no damage in all box floor samples at the normal service load of 2.5 kN/m2, and the maximum deflection was far less than the allowable value. When the maximum load was applied, the load-displacement curve of each floor sample exhibited a linear relationship without obvious failure. However, localized failure was manifested as the dislocation slip of the rib beams relative to the upper and lower floor slabs at the corner nodes and the joint expansion and staggered floors at the bottom plate, with obvious failure signs. The rib beam height had the most significant impact on the floor stiffness, followed by the spacing of short-side rib beams, whereas the OSB plate thickness had lest impact. The mid-span deflections of poplar LVL orthogonal ribbed box floor samples, which were calculated using the analog slab method, were in good agreement with the experimental results with an error being less than 10%.
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Dourakopoulos, J. A., and E. J. Sapountzakis. "Nonlinear Dynamic Analysis of Plates Stiffened by Parallel Beams with Deformable Connection." Advances in Civil Engineering 2014 (2014): 1–22. http://dx.doi.org/10.1155/2014/942763.
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In this paper a general solution to the geometrically nonlinear dynamic analysis of plates stiffened by arbitrarily placed parallel beams of arbitrary doubly symmetric cross-section, subjected to dynamic loading, is presented. The plate-beam structure is assumed to undergo moderate large deflections and the nonlinear analysis is carried out by retaining nonlinear terms in the kinematical relations. According to the proposed model, the arbitrarily placed parallel stiffening beams are isolated from the plate by sections in the lower outer surface of the plate, making the hypothesis that the plate and the beams can slip in all directions of the connection without separation and taking into account the arising tractions in all directions at the fictitious interfaces. These tractions are integrated with respect to each half of the interface width resulting in two interface lines, along which the loading of the beams and the additional loading of the plate are defined. Six boundary value problems are formulated and solved using the analog equation method (AEM), a BEM-based method. Both free and forced transverse vibrations are considered and numerical examples with great practical interest are presented demonstrating the effectiveness, wherever possible, the accuracy, and the range of applications of the proposed method.
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Peřina, Jan, Ondřej Haderka, Alessia Allevi, and Maria Bondani. "Absolute calibration of photon-number-resolving detectors with an analog output using twin beams." Applied Physics Letters 104, no. 4 (January 27, 2014): 041113. http://dx.doi.org/10.1063/1.4863433.
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Oh, Semyoung, Young-Dam Kim, and Daejin Park. "Optimized Combination of Local Beams for Wireless Sensor Networks." Sensors 19, no. 3 (February 2, 2019): 633. http://dx.doi.org/10.3390/s19030633.
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This paper proposes an optimization algorithm to determine the optimal coherent combination candidates of distributed local beams in a wireless sensor network. The beams are generated from analog uniform linear arrays of nodes and headed toward the random directions due to the irregular surface where the nodes are mounted. Our algorithm is based on one of the meta-heuristic schemes (i.e., the single-objective simulated annealing) and designed to solve the objective of minimizing the average interference-to-noise ratio (INR) under the millimeter wave channel, which leads to the reduction of sidelobes. The simulation results show that synthesizing the beams on the given system can form a deterministic mainlobe with considerable and unpredictable sidelobes in undesired directions, and the proposed algorithm can decrease the average INR (i.e., the average improvement of 12.2 dB and 3.1 dB are observed in the directions of π 6 and 2 π 3 , respectively) significantly without the severe loss of signal-to-noise ratio (SNR) in the desired direction.
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Soifer, Victor A., Nikita V. Golovastikov, Leonid L. Doskolovich, Evgeni A. Bezus, and Dmitry A. Bykov. "Differentiation of Optical Signals with Dielectric Ridges on Top of a Slab Waveguide." Vestnik RFFI, no. 3 (July 31, 2019): 35–45. http://dx.doi.org/10.22204/2410-4639-2019-103-03-35-45.
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We propose two simple planar structures that enable spatial differentiation of the profile of optical beams propagating in a slab waveguide. The differentiator operating in transmission consists of a single subwavelength dielectric ridge on the surface of a slab waveguide. The differentiator operating in reflection consists of two grooves on the surface of a slab waveguide. In both cases the differentiation is performed at oblique incidence of the beam and is associated with the resonant excitation of the considered structures eigenmodes localized at the ridge or at the ridge between two grooves. It is shown that the required balance between the differentiation quality and the amplitude of the differentiated beam can be achieved by manipulating the quality factor of the resonance. The presented numerical simulation results demonstrate high-quality differentiation. The proposed differentiator may find application in ultrafast analog computing and signal processing systems.
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SAPOUNTZAKIS, EVANGELOS J., and JOHN T. KATSIKADELIS. "INFLUENCE OF THE INPLANE BOUNDARY CONDITIONS ON THE VIBRATION FREQUENCIES AND BUCKLING LOAD OF RIBBED PLATES." International Journal of Structural Stability and Dynamics 02, no. 01 (March 2002): 25–43. http://dx.doi.org/10.1142/s0219455402000385.
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In this paper, the influence of the inplane boundary conditions on the vibration frequencies and the buckling load of plates reinforced with a system of parallel beams is presented. The adopted model for the dynamic analysis of the ribbed plate takes into account the resulting inplane forces and deformations of the plate as well as the axial forces and deformations of the beam, due to combined response of the system. The analysis consists in isolating the beams from the plate by sections parallel to the lower outer surface of the plate. The analysis of the vibration problem of a ribbed plate subjected to inplane forces is based on the capability to establish a flexibility matrix with respect to a set of nodal mass points using the Analog Equation Method (AEM) for the static ribbed plate problem. Moreover, a lumped mass matrix is constructed from the tributary mass areas to the nodal mass points. The buckling load is established using the dynamic criterion. From the obtained results it is shown that both the vibration frequencies and the buckling load may be significantly influenced by the inplane boundary conditions.
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Ellakany, Ahmed M., Mohamad Ali, Mohamed A. El-Gohary, and Mohamed Elkholy. "Lumped system model for elastic steel-concrete beams with partial interaction." Multidiscipline Modeling in Materials and Structures 16, no. 1 (September 6, 2019): 121–33. http://dx.doi.org/10.1108/mmms-01-2019-0007.
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Purpose The purpose of this paper is to introduce a numerical model to investigate static response of elastic steel-concrete beams. The numerical model is based on the lumped system with the combination of the transfer matrix and the analog beam methods (ABM). The beams are composed of an upper concrete slab and a lower steel beam, connected at the interface by shear transmitting studs. This type of beam is widely used in constructions especially for highway bridges. The static field and point transfer matrices for the element of the elastic composite beam are derived. The present model is verified and is applied to study the static response of elastic composite beams with intermediate conditions. The intermediate condition is considered as an elastic support with various values of stiffness. The elastic support can be considered rigid when the stiffness has very high values. The influence effect of shear stiffness between the upper slab and lower beam, and the end shear restraint on the static behavior of the composite beams is studied. In addition, the change in the stiffness of the elastic support is also highlighted. Design/methodology/approach The objective of this study is to introduce a numerical model based on lumped system to calculate the static performance of elastic composite bridge beams having intermediate elastic support by combining the ABM with the transfer matrix method (TMM). The developed model is applicable for studying static and dynamic responses of steel-concrete elastic composite beams with different end conditions taking into account the effect of partial shear interactions. The validity of the lumped mass model is checked by comparing its results with a distributed model and good agreements are achieved (Ellakany and Tablia, 2010). Findings A model based on the lumped system of the elastic composite steel-concrete bridge beam with intermediate elastic support under static load is presented. The model takes into consideration the effect of the end shear restraint together with the interaction between the upper slab and the lower beam. Combining the analogical beam method with the TMM and analyzing the behavior of the elastic composite beam in terms of shear studs and stiffness, the following outcomes can be drawn: end shear restraint and stiffness of the shear layer are the two main factors affecting the response of elastic composite beams in terms of both the deflection and the moments. Using end shear restraint reduces the deflection extensively by about 40 percent compared to if it is not used assuming that: there is no interaction between the upper slab and the lower beam and the beam is acting as simply supported. As long as the shear layer stiffness increases or interaction exists, the deflection decreases. This reduced rate in deflection is smaller in case of existence of end shear restraint. The effect of the end shear restraint is more prevailing on reducing the deflections in case of partial interactions. However, its effect completely diminishes in case of complete interaction. Presence of the end shear restraint and shear layer stiffness produces almost the same variations in the components of the bending moments of the composite beam. Finally, for a complete interaction, comparing the case of using end shear restraint or the case without it, the differences in the values of the deflections and moments are almost negligible. Research limitations/implications The following assumptions related to the theory of ABM: shear studs connecting both sub-beams are modeled as a thin shear layer, each sub-beam has the same vertical displacement and the shear deformation in the sub-beams is neglected. Practical implications The developed model can be effectively used for a quick estimation of the dynamic responses of elastic composite beams in real life rather than utilizing complicated numerical models. Social implications The applications of this model can be further extended for studying the behavior of complex bridge beams that will guarantee the safety of the public in a quick view. Originality/value Previous models combined the TMM with the ABM for studying the static and free-vibration behaviors of elastic composite beams assuming that the field element is subjected to a distributed load. To study the dynamic response of elastic composite beams subjected to different moving loads using transfer matrix ABM, it was essential to use a massless field element and concentrate the own weight of the beam at the point element. This model is considered a first step for studying the impact factors of elastic composite beams subjected to moving loads.
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Sapountzakis, EJ, and IN Tsiptsis. "Generalized vibration analysis of beams including warping effects by isogeometric methods." Journal of Vibration and Control 24, no. 6 (January 5, 2017): 1032–50. http://dx.doi.org/10.1177/1077546316685679.
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In this paper, the Isogeometric tools, either integrated in the Finite Element Method (FEM) or in a Boundary Element based Method (BEM) called Analog Equation Method (AEM), are employed for the vibration analysis of homogeneous beams of arbitrary cross section (thin- or thick- walled) taking into account nonuniform warping and shear deformation effects (shear lag due to both flexure and torsion). The beam is subjected to the combined action of arbitrarily distributed or concentrated axial and transverse loading, as well as to bending, twisting and warping moments. Its edges are subjected to the most general boundary conditions. By employing a distributed mass model system accounting for longitudinal, transverse, rotatory, torsional and warping inertia, ten boundary value problems with respect to the variable along the beam time-dependent 1-D kinematical components are formulated. The numerical solution or the spectrum analysis of the aforementioned problems is performed through IGA, FEM and AEM, leading to a system of second-order differential equations, which are quasi-static and solved for the free vibration case, formulating a generalized eigenvalue problem. Special cases of the generalized problem have also been studied in order to demonstrate the efficiency of AEM in reducing computational effort and improving accuracy, especially when combined to Isogeometric tools, such as NURBS and B-splines.
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Schoonderbeek, Gijs, Boudewijn Hut, E. Kooistra, Á. Mika, H. J. Pepping, A. W. Gunst, and W. A. van Cappellen. "Implementation of a Correlator onto a Hardware Beam-Former to Calculate Beam-Weights." Journal of Astronomical Instrumentation 09, no. 02 (June 2020): 2050007. http://dx.doi.org/10.1142/s2251171720500075.
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One of the main technologies to open up a wider field of view for today’s radio telescopes are phased arrays. This is especially the case for radio astronomy instruments operating below 2[Formula: see text]GHz. Nowadays, the existing dish-type instruments are being upgraded with phased array feeds (PAF) in the focal plane. This increases the field of view at the expense of needing more analog electronics and digital signal processing. One of the digital signal processing functionalities used to combine the digitized signals from the PAF is a beam-former which creates multiple high sensitivity beams within the field of view of the dish. Before beams can be formed, the signals from the PAF need to be calibrated using a correlator. In this paper, we present a solution where these two operations are combined by using the beam-former also as a correlator. The statistics unit used as part of the beam-former implementation, can be used as well for calculating correlation products. With the proper settings of the beam-former weight of each beamlet, a frequency sub-band with a direction, can be used as a single cross correlation product. By implementing the correlator on the beam-former, the digital resources and development time can be reduced. To validate the idea, two versions of the algorithm are implemented in the Apertif PAF system on the Westerbork Synthesis Radio Telescope (WSRT). Results show that two full-bandwidth correlation matrices per beam, needed to determine the static beam weights for the calibration, and a single column of the correlation matrix, used to compensate for any drift between the receiver chains, can be performed.
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Hefnawi, Mostafa. "Hybrid Beamforming for Millimeter-Wave Heterogeneous Networks." Electronics 8, no. 2 (January 28, 2019): 133. http://dx.doi.org/10.3390/electronics8020133.
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Heterogeneous networks (HetNets) employing massive multiple-input multiple-output (MIMO) and millimeter-wave (mmWave) technologies have emerged as a promising solution to enhance the network capacity and coverage of next-generation 5G cellular networks. However, the use of traditional fully-digital MIMO beamforming methods, which require one radio frequency (RF) chain per antenna element, is not practical for large-scale antenna arrays, due to the high cost and high power consumption. To reduce the number of RF chains, hybrid analog and digital beamforming has been proposed as an alternative structure. In this paper, therefore, we consider a HetNet formed with one macro-cell base station (MBS) and multiple small-cell base stations (SBSs) equipped with large-scale antenna arrays that employ hybrid analog and digital beamforming. The analog beamforming weight vectors of the MBS and the SBSs correspond to the the best-fixed multi-beams obtained by eigendecomposition schemes. On the other hand, digital beamforming weights are optimized to maximize the receive signal-to-interference-plus-noise ratio (SINR) of the effective channels consisting of the cascade of the analog beamforming weights and the actual channel. The performance is evaluated in terms of the beampatterns and the ergodic channel capacity and shows that the proposed hybrid beamforming scheme achieves near-optimal performance with only four RF chains while requiring considerably less computational complexity.
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Jiang, Jing, and Deting Kong. "Joint User Scheduling and MU-MIMO Hybrid Beamforming Algorithm for mmWave FDMA Massive MIMO System." International Journal of Antennas and Propagation 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/4341068.
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The large bandwidth and multipath in millimeter wave (mmWave) cellular system assure the existence of frequency selective channels; it is necessary that mmWave system remains with frequency division multiple access (FDMA) and user scheduling. But for the hybrid beamforming system, the analog beamforming is implemented by the same phase shifts in the entire frequency band, and the wideband phase shifts may not be harmonious with all users scheduled in frequency resources. This paper proposes a joint user scheduling and multiuser hybrid beamforming algorithm for downlink massive multiple input multiple output (MIMO) orthogonal frequency division multiple access (OFDMA) systems. In the first step of user scheduling, the users with identical optimal beams form an OFDMA user group and multiplex the entire frequency resource. Then base station (BS) allocates the frequency resources for each member of OFDMA user group. An OFDMA user group can be regarded as a virtual user; thus it can support arbitrary MU-MIMO user selection and beamforming algorithms. Further, the analog beamforming vectors employ the best beam of each selected MU-MIMO user and the digital beamforming algorithm is solved by weight MMSE to acquire the best performance gain and mitigate the interuser inference. Simulation results show that hybrid beamforming together with user scheduling can greatly improve the performance of mmWave OFDMA massive MU-MIMO system.
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Burlon, Andrea, Giuseppe Failla, and Felice Arena. "An improved analog equation method for non-linear dynamic analysis of time-fractional beams with discontinuities." Meccanica 55, no. 4 (February 10, 2020): 649–68. http://dx.doi.org/10.1007/s11012-020-01130-4.
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Kim, Bobae, Uk-Won Nam, Sunghwan Kim, Sukwon Youn, Won-Kee Park, Jongdae Sohn, Hong Joo Kim, et al. "A Study on the Performance of a Silicon Photodiode Sensor for a Particle Dosimeter and Spectrometer." Sensors 21, no. 23 (December 1, 2021): 8029. http://dx.doi.org/10.3390/s21238029.
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A lunar vehicle radiation dosimeter (LVRAD) has been proposed for studying the radiation environment on the lunar surface and evaluating its impact on human health. The LVRAD payload comprises four systems: a particle dosimeter and spectrometer (PDS), a tissue-equivalent dosimeter, a fast neutron spectrometer, and an epithermal neutron spectrometer. A silicon photodiode sensor with compact readout electronics was proposed for the PDS. The PDS system aims to measure protons with 10–100 MeV of energy and assess dose in the lunar space environment. The manufactured silicon photodiode sensor has an effective area of 20 mm × 20 mm and thickness of 650 μm; the electronics consist of an amplifier, analog pulse processor, and a 12-bit analog-to-digital converter for signal readout. We studied the responses of silicon sensors which were manufactured with self-made electronics to gamma rays with a wide range of energies and proton beams.
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Braach, Justus, Eric Buschmann, Dominik Dannheim, Katharina Dort, Thanushan Kugathasan, Magdalena Munker, Walter Snoeys, and Mateus Vicente. "Performance of the FASTPIX Sub-Nanosecond CMOS Pixel Sensor Demonstrator." Instruments 6, no. 1 (February 8, 2022): 13. http://dx.doi.org/10.3390/instruments6010013.
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Within the ATTRACT FASTPIX project, a monolithic pixel sensor demonstrator chip has been developed in a modified 180 nm CMOS imaging process, targeting sub-nanosecond timing measurements for single ionizing particles. It features a small collection electrode design on a 25 micron thick epitaxial layer and contains 32 mini matrices of 68 hexagonal pixels each, with pixel pitches ranging from 8.66 to 20 micron. Four pixels are transmitting an analog output signal and 64 are transmitting binary hit information. Various design variations are explored, aiming at accelerating the charge collection and making the timing of the charge collection more uniform over the pixel area. Signal treatment of the analog waveforms, as well as reconstruction of time and charge information, is carried out off-chip. This contribution introduces the design of the sensor and readout system and presents the first performance results for 10 μm and 20 μm pixel pitch achieved in measurements with particle beams.
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Fedele, Renato, Fatema Tanjia, Dusan Jovanović, Sergio De Nicola, and Concetta Ronsivalle. "Wave theories of non-laminar charged particle beams: from quantum to thermal regime." Journal of Plasma Physics 80, no. 2 (January 15, 2014): 133–45. http://dx.doi.org/10.1017/s0022377813000913.
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AbstractThe standard classical description of non-laminar charged particle beams in paraxial approximation is extended to the context of two wave theories. The first theory that we discuss (Fedele R. and Shukla, P. K. 1992 Phys. Rev. A45, 4045. Tanjia, F. et al. 2011 Proceedings of the 38th EPS Conference on Plasma Physics, Vol. 35G. Strasbourg, France: European Physical Society) is based on the Thermal Wave Model (TWM) (Fedele, R. and Miele, G. 1991 Nuovo Cim. D13, 1527.) that interprets the paraxial thermal spreading of beam particles as the analog of quantum diffraction. The other theory is based on a recently developed model (Fedele, R. et al. 2012a Phys. Plasmas19, 102106; Fedele, R. et al. 2012b AIP Conf. Proc.1421, 212), hereafter called Quantum Wave Model (QWM), that takes into account the individual quantum nature of single beam particle (uncertainty principle and spin) and provides collective description of beam transport in the presence of quantum paraxial diffraction. Both in quantum and quantum-like regimes, the beam transport is governed by a 2D non-local Schrödinger equation, with self-interaction coming from the nonlinear charge- and current-densities. An envelope equation of the Ermakov–Pinney type, which includes collective effects, is derived for both TWM and QWM regimes. In TWM, such description recovers the well-known Sacherer's equation (Sacherer, F. J. 1971 IEEE Trans. Nucl. Sci.NS-18, 1105). Conversely, in the quantum regime and in Hartree's mean field approximation, one recovers the evolution equation for a single-particle spot size, i.e. for a single quantum ray spot in the transverse plane (Compton regime). We demonstrate that such quantum evolution equation contains the same information as the evolution equation for the beam spot size that describes the beam as a whole. This is done heuristically by defining the lowest QWM state accessible by a system of non-overlapping fermions. The latter are associated with temperature values that are sufficiently low to make the single-particle quantum effects visible on the beam scale, but sufficiently high to make the overlapping of the single-particle wave functions negligible. This lowest QWM state constitutes the border between the fundamental single-particle Compton regime and the collective quantum and thermal regimes at larger (nano- to micro-) scales. Comparing it with the beam parameters in the existing accelerators, we find that it is feasible to achieve nano-sized beams in advanced compact machines.
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Zhao, Kao Zhong, and Jian Jiang Liu. "Multiple Cross-Laminated Container Floor Temperature Field Based on ANSYS." Applied Mechanics and Materials 578-579 (July 2014): 83–88. http://dx.doi.org/10.4028/www.scientific.net/amm.578-579.83.
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Concrete composite beam floor cage floor as a new form , with a saving of steel and concrete , lighter weight, the advantages of high capacity , and has been more widely used in engineering. Therefore , to carry out the new concrete composite beam floor cages fire behavior for large spaces , large span areas is necessary. This article is the use of finite element software ANSYS multi-span composite floor beams cages fire tests to simulate life and death through SOLID70 unit features analog composite bottom plate before and after bursting floor temperature field and gives composite floor box overall temperature distribution along the rib cloud cover and the temperature of the beam cross-section of different heights - time curve , finally, the simulation results and experimental conditions were compared and analyzed , the main draw the following conclusions : the use of ANSYS thermal unit SOLID70 cell function and death can be simulated temperature distribution in case of fire concrete composite floor beam floor cages before and after bursting through the ribbed section of different heights temperature - time curve can be seen, the test results agree well with the simulation results ; testing process with increasing temperature , floor surface inlets, stacked boxes floor temperature contours directly reflects the law during the test floor surface appears inlets .
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Pan, James N. "Chromatic and Panchromatic Nonlinear Optoelectronic CMOSFETs for CMOS Image Sensors, Laser Multiplexing, Computing, and Communication." MRS Advances 5, no. 37-38 (2020): 1965–74. http://dx.doi.org/10.1557/adv.2020.273.
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AbstractTraditionally, CMOS transistors are for low power, high speed, and high packing density applications. CMOS is also commonly used as power regulating devices, and light sensors (CCD or CMOS image sensors). In this paper, we would like to introduce Photonic CMOS as a light emitting device for optical computing, ASIC, power transistors, and ultra large scale integration (ULSI). A Photonic CMOS Field Effect Transistor is fabricated with a low-resistance laser or LED in the drain region, and multiple photon sensors in the channel / well regions. The MOSFET, laser, and photon sensors are fabricated as one integral transistor. With embedded nonlinear optical films, the Photonic CMOSFETs have the capability of detecting and generating focused laser beams of various frequencies to perform optical computing, signal modulation, polarization, and multiplexing for digital / analog processing and communication.
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Staley, Douglas A. "Langevin's influence on relativity theories." Physics Essays 33, no. 4 (December 25, 2020): 380–86. http://dx.doi.org/10.4006/0836-1398-33.4.380.
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A century ago, Paul Langevin [C. R. 173, 831 (1921)], through his influence, convinced the scientific community that Einstein's theories of relativity were correct and could explain the Sagnac effect. A simple note in Comptes Rendus was all it took to silence many prominent skeptical scientists. The relativity skeptics had pointed to Sagnac's experiment [C. R. 157, 1410 (1913)] with the interference of counter rotating light beams as proof that the speed of light was not the same in both directions, contrary to the key postulate in Einstein's theory. Langevin showed that the result was also explained by relativity. The rest is history, and relativity has remained a center piece of theoretical physics ever since. Langevin had been captivated by solar eclipse observations of a shifted star pattern near the sun as reported by Eddington [Report on the Relativity Theory of Gravitation (Fleetway Press, Ltd., London, 1920)]. This was taken as proof positive for Einstein's General Theory of Relativity. The case of a light beam split into two beams, which propagate in opposite directions around a circuit, has an analog in a simple thought experiment—a speed test for runners. Two runners can be timed on a running track with the runners going around the track in opposite directions. Two stop watches will display the time for each runner's return to the starting position. The arithmetic difference in time shown on each stop watch will provide the differences in speed between the two runners. If the two speeds are the same, the time difference will be zero. It would not make any sense for one of the stop watches to measure a negative time, that is, time moving into the past. In fact, the idea is absurd! However, Langevin did just that, assigned the time for light to travel in one direction as positive while the time for the light to traverse in the opposite direction as negative, moving into the past! By so doing, Langevin reproduced Sagnac's expression and declared that relativity explains Sagnac's experiment. Langevin was wrong!
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BLANCHARD, DOMINIQUE, and GEORGES GRISO. "DECOMPOSITION OF DEFORMATIONS OF THIN RODS: APPLICATION TO NONLINEAR ELASTICITY." Analysis and Applications 07, no. 01 (January 2009): 21–71. http://dx.doi.org/10.1142/s021953050900130x.
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This paper deals with the introduction of a decomposition of the deformations of curved thin beams, with section of order δ, which takes into account the specific geometry of such beams. A deformation v is split into an elementary deformation and a warping. The elementary deformation is the analog of a Bernoulli–Navier's displacement for linearized deformations replacing the infinitesimal rotation by a rotation in SO(3) in each cross section of the rod. Each part of the decomposition is estimated with respect to the L2norm of the distance from gradient v to SO(3). This result relies on revisiting the rigidity theorem of Friesecke–James–Müller in which we estimate the constant for a bounded open set star-shaped with respect to a ball. Then we use the decomposition of the deformations to derive a few types of asymptotic geometrical behavior: large deformations of extensional type, inextensional deformations and linearized deformations. To illustrate the use of our decomposition in nonlinear elasticity, we consider a St Venant–Kirchhoff material and upon various scalings on the applied forces we obtain the Γ-limit of the rescaled elastic energy. We first analyze the case of bending forces of order δ2which leads to a nonlinear extensible model. Smaller pure bending forces give the classical linearized model. A coupled extentional-bending model is obtained for a class of forces of order δ2in traction and of order δ3in bending.
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Liu, Bin, and Yan Ren. "A design of laser array harp based on multi-dimensional wavelet transform and audio signal reconstruction." Journal of Physics: Conference Series 2113, no. 1 (November 1, 2021): 012059. http://dx.doi.org/10.1088/1742-6596/2113/1/012059.
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Abstract This paper introduces a design scheme of laser array harp based on multi-dimensional wavelet transform and audio signal reconstruction. The green light beams from multiple high-power lasers simulate harp strings, use photoresistors as the signal receiving end, and use a signal conditioning system composed of analog circuits and LM393 comparators to collect and adjust the resistance signal of the laser sensor[1], and finally it is adjusted to a level signal that can be recognized by the CPU. After receiving the signal, the CPU core board analyzes the string signal, and sends control commands to the audio processing system through the industrial bus according to the analyzed digital signal. After receiving the control command, the audio processing system uses the audio signal reconstruction technology composed of multi-dimensional wavelet packets, deep learning and other algorithms to simulate the audio signals of various string music, so as to achieve the purposes of using the lasers as virtual strings and imitating musical instruments for musical performance.[2]
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Lymanets, A. "The Silicon Tracking System of the CBM Experiment at FAIR." Ukrainian Journal of Physics 64, no. 7 (September 17, 2019): 607. http://dx.doi.org/10.15407/ujpe64.7.607.
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The Compressed Baryonic Matter (CBM) experiment at FAIR (Darmstadt, Germany) is designed to study the dense nuclear matter in a fixed target configuration with heavy ion beams up to kinetic energies of 11 AGeV for Au+Au collision. The charged particle tracking with below 2% momentum resolution will be performed by the Silicon Tracking System (STS) located in the aperture of a dipole magnet. The detector will be able to reconstruct secondary decay vertices of rare probes, e.g., multistrange hyperons, with 50 мm spatial resolution in the heavy-ion collision environment with up to 1000 charged particle per inelastic interaction at the 10 MHz collision rate. This task requires a highly granular fast detector with radiation tolerance enough to withstand a particle fluence of up to 1014 neq/cm2 1-MeV equivalent accumulated over several years of operation. The system comprises 8 tracking stations based on double-sided silicon microstrip sensors with 58 мm pitch and strips oriented at 7.5∘ stereo angle. The analog signals are read out via stacked microcables (up to 50 cm long) by the front-end electronics based on the STS-XYTER ASIC with self-triggering architecture. Detector modules with this structure will have a material budget between 0.3% and 1.5% radiation length increasing towards the periphery. First detector modules and ladders built from pre-final components have been operated in the demonstrator experiment mCBM at GSI-SIS18 (FAIR Phase-0) providing a test stand for the performance evaluation and system integration. The results of mSTS detector commissioning and the performance in the beam will be presented.
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Jadhav, Shubham, Ved Gund, Benyamin Davaji, Debdeep Jena, Huili (Grace) Xing, and Amit Lal. "HZO-based FerroNEMS MAC for in-memory computing." Applied Physics Letters 121, no. 19 (November 7, 2022): 193503. http://dx.doi.org/10.1063/5.0120629.
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This paper demonstrates a hafnium zirconium oxide (HZO)-based ferroelectric NEMS unimorph as the fundamental building block for very low-energy capacitive readout in-memory computing. The reported device consists of a [Formula: see text]2 unimorph cantilever with 20-nm-thick ferroelectric HZO on 1 μm SiO2. Partial ferroelectric switching in HZO achieves analog programmable control of the piezoelectric coefficient (d31), which serves as the computational weight for multiply accumulate (MAC) operations. The displacement of the piezoelectric unimorph was recorded by actuating the device with different input voltages Vin. The resulting displacement was measured as a function of the ferroelectric programming/poling voltage [Formula: see text]. The slopes of central beam displacement (δmax) vs Vin were measured to be between 182.9 nm/V (for −8 Vp) and −90.5 nm/V (for 8 Vp), which corresponds to displacement proportionality constant β of 68 nm/V2 for +ve Vp and 47 nm/V2 for −ve Vp, demonstrating linear behavior of the multiplier unit. The resultant δmax from AC actuation is in the range of −18 to 36 nm and is a scaled product of Vin and programmed d31 (governed by the Vp). The multiplication function serves as the fundamental unit for MAC operations with the ferroelectric NEMS unimorph. The displacement from many such beams can be added by summing the capacitance changes, providing a pathway to implement a multi-input and multi-weight neuron. A scaling and fabrication analysis suggests that this device can be CMOS compatible, achieving high in-memory computational throughput.
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Toso, Giovanni, and Piero Angeletti. "An Optimal Procedure for the Design of Discrete Constrained Lens Antennas with Minimized Optical Aberrations. Part II: Three-Dimensional Multifocal Architectures." Electronics 11, no. 3 (February 8, 2022): 503. http://dx.doi.org/10.3390/electronics11030503.
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Novel three-dimensional discrete lens antennas characterized by a number of focal points ranging from one to five and defined explicitly via analytical equations are presented in the paper. A procedure to derive rotationally symmetric afocal lenses starting from multifocal lenses that are not rotationally symmetric is proposed as well. In addition, an innovative method to identify the focal surface minimizing the optical aberrations is derived. The lenses are compared in terms of optical aberrations and accommodation constraints. The most suitable lens architectures depend mainly on the required angular field of view and magnification factor. It is shown that a reduction by a factor close to 3 in the optical aberrations can be obtained when selecting the most appropriate lens architecture and keeping comparable accommodation constraints. The results, derived exploiting a geometrical optics (GO) formulation, provide useful indications for the preliminary design of constrained lens antennas before adopting full wave rigorous techniques. Three-dimensional discrete lens antennas can offer significant advantages as compared to conventional analog beamforming networks (as those based on Butler matrixes) in terms of frequency bandwidth, number of beams and number of radiating elements.
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Lavezzi, L., M. Alexeev, A. Amoroso, R. Baldini Ferroli, M. Bertani, D. Bettoni, F. Bianchi, et al. "The New Cylindrical GEM Inner Tracker of BESIII." International Journal of Modern Physics: Conference Series 46 (January 2018): 1860077. http://dx.doi.org/10.1142/s2010194518600777.
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The Cylindrical GEM-Inner Tracker (CGEM-IT) is the upgrade of the internal tracking system of the BESIII experiment. It consists of three layers of cylindrically-shaped triple GEMs, with important innovations with respect to the existing GEM detectors, in order to achieve the best performance with the lowest material budget. It will be the first cylindrical GEM running with analog readout inside a 1T magnetic field. The simultaneous measurement of both the deposited charge and the signal time will permit to use a combination of two algorithms to evaluate the spatial position of the charged tracks inside the CGEM-IT: the charge centroid and the micro time projection chamber modes. They are complementary and can cope with the asymmetry of the electron avalanche when running in magnetic field and with non-orthogonal incident tracks. To evaluate the behaviour under different working settings, both planar chambers and the first cylindrical prototype have been tested during various test beams at CERN with 150 GeV/[Formula: see text] muons and pions. This paper reports the results obtained with the two reconstruction methods and a comparison between the planar and cylindrical chambers.
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Fishbine, Brian H., and Robert J. Macy. "Fsem: Fast Scanning Electron Microscopy." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 1 (August 12, 1990): 606–7. http://dx.doi.org/10.1017/s0424820100181798.
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Commercially available SEM‘s offer a maximum “TV” framing rate of ∼30 Hz. We have obtained a digitally-acquired framing rate of 381 Hz with submicron resolution [1]. This is at a 25 MHz pixel rate, compared with the ≤4 MHz video bandwidth of TV-rate machines. We have also performed analog-acquired experiments at effective framing rates of 4.9 kHz and effective pixel rates of >50 MHz. Our present detection and recording system is capable of 200 MHz pixel rates, with reduced contrast range at higher rates. Extrapolating current technology suggests that GHz pixel rates with useable final image signal-to-noise ratios are possible [2].In large part, the success of electron microscopy is due to: the high resolution possible with the small de Broglie wavelength of even keV electrons, small effective electron source diameters, and small optical aberrations of well-designed electron optics. With this resolution, SEM also attains large depth of focus with scanned, narrow electron beams. SEM micrographs are generally noted for exceptional sharpness and large depth of focus. The highest quality micrographs require scan times of tens of seconds or more.
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Carmichael, Stephen W. "Microscopy is Only Skin Deep." Microscopy Today 19, no. 3 (April 28, 2011): 8. http://dx.doi.org/10.1017/s1551929511000368.
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Light optical imaging techniques that don't require labels are attractive for human studies because they are not toxic nor do they perturb the system being studied. Whereas there are several methods available to provide microscopic imaging below the surface of a tissue, they each suffer from limitations, such as low spatiotemporal resolution and a limited number of molecular signatures that can be imaged. Raman spectroscopy offers label-free contrast for major chemical species in tissue, such as water, lipids, DNA, and proteins based on vibrational spectra at light optical wavelengths. However, the Raman signal is very weak, which makes it difficult to image a sample with good temporal resolution. The recent development of stimulated Raman scattering (SRS) microscopy can overcome these limitations as demonstrated by the elegant studies of Brian Saar, Christian Freudiger, Jay Reichman, Michael Stanley, Gary Holton, and Sunney Xie. Saar et al. improved the optics and electronics for the acquisition of the backscattered signal of SRS. In SRS microscopy, the sample is excited by two lasers at different frequencies. When the difference in frequency matches a molecular vibration in the sample, the intensities of the probes change in a predictable manner. These intensity changes are small, but Saar et al. developed a new method to detect them. They chopped one of the laser beams at high frequency (MHz) and detected the intensity change in the other beam, which offered superior sensitivity. The key component was a custom-made all-analog lock-in amplifier with a very short (about 100 ns) response time. The laser probe wavelengths were tuned to match a vibrational frequency of interest and raster-scanned across the sample. Frequencies were tuned to detect CH2 stretching (primarily for lipids), OH stretching (primarily water), and CH3 stretching (primarily proteins) vibrations. Imaging of water is of particular interest in studying the transport of water-soluble compounds such as drugs.
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Thirunavukkarasu, G., M. Mousley, M. Babiker, and J. Yuan. "Normal modes and mode transformation of pure electron vortex beams." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 375, no. 2087 (February 28, 2017): 20150438. http://dx.doi.org/10.1098/rsta.2015.0438.
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Electron vortex beams constitute the first class of matter vortex beams which are currently routinely produced in the laboratory. Here, we briefly review the progress of this nascent field and put forward a natural quantum basis set which we show is suitable for the description of electron vortex beams. The normal modes are truncated Bessel beams (TBBs) defined in the aperture plane or the Fourier transform of the transverse structure of the TBBs (FT-TBBs) in the focal plane of a lens with the said aperture. As these modes are eigenfunctions of the axial orbital angular momentum operator, they can provide a complete description of the two-dimensional transverse distribution of the wave function of any electron vortex beam in such a system, in analogy with the prominent role Laguerre–Gaussian (LG) beams played in the description of optical vortex beams. The characteristics of the normal modes of TBBs and FT-TBBs are described, including the quantized orbital angular momentum (in terms of the winding number l ) and the radial index p >0. We present the experimental realization of such beams using computer-generated holograms. The mode analysis can be carried out using astigmatic transformation optics, demonstrating close analogy with the astigmatic mode transformation between LG and Hermite–Gaussian beams. This article is part of the themed issue ‘Optical orbital angular momentum’.
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ASTHANA, M. V., A. GIULIETTI, DINESH VARSHNEY, and M. S. SODHA. "Relativistic self-focusing of a rippled laser beam in a plasma." Journal of Plasma Physics 62, no. 4 (October 1999): 389–96. http://dx.doi.org/10.1017/s0022377899008016.
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This paper presents an analysis of the relativistic self-focusing of a rippled Gaussian laser beam in a plasma. Considering the nonlinearity as arising owing to relativistic variation of mass, and following the WKB and paraxial-ray approximations, the phenomenon of self-focusing of rippled laser beams is studied for arbitrary magnitude of nonlinearity. Pandey et al. [Phys. Fluids82, 1221 (1990)] have shown that a small ripple on the axis of the main beam grows very rapidly with distance of propagation as compared with the self-focusing of the main beam. Based on this analogy, we have analysed relativistic self-focusing of rippled beams in plasmas. The relativistic intensities with saturation effects of nonlinearity allow the nonlinear refractive index in the paraxial regime to have a slower radial dependence, and thus the ripple extracts relatively less energy from its neighbourhood.
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Irnich, Dominik, Norbert Salih, Martin Offenbächer, and Johannes Fleckenstein. "Is Sham Laser a Valid Control for Acupuncture Trials?" Evidence-Based Complementary and Alternative Medicine 2011 (2011): 1–8. http://dx.doi.org/10.1093/ecam/neq009.
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Methodological problems of acupuncture trials focus on adequate placebo controls. In this trial we evaluated the use of sham laser acupuncture as a control procedure. Thirty-four healthy volunteers received verum laser (invisible infrared laser emission and red light, 45 s and 1 J per point) and sham laser (red light) treatment at three acupuncture points (LI4, LU7 and LR3) in a randomized, double-blinded, cross-over design. The main outcome measure was the ratio of correct to incorrect ratings of treatment immediately after each session. The secondary outcome measure was the occurrence of deqi-like sensations at the acupuncture points and their intensity on a 10-fold visual analog scale (VAS; 10 being the strongest sensible sensation). We pooled the results of three former trials to evaluate the credibility of sham laser acupuncture when compared to needle acupuncture. Fifteen out of 34 (44%) healthy volunteers (age: 28 ± 10.7 years) identified the used laser device after the first session and 14 (41%) after the second session. Hence, both treatments were undistinguishable (P= .26). Deqi-like sensations occurred in 46% of active laser (2.34 VAS) and in 49.0% of sham laser beams (2.49 VAS). The credibility of sham laser was not different from needle acupuncture. Sham laser acupuncture can serve as a valid placebo control in laser acupuncture studies. Due to similar credibility and the lack of sensory input on the peripheral nervous system, sham laser acupuncture can also serve as a sham control for acupuncture trials, in order to evaluate needling effectsper se.
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Spreeuw, Robert J. C. "Spiraling light: from donut modes to a Magnus effect analogy." Nanophotonics 11, no. 4 (November 11, 2021): 633–44. http://dx.doi.org/10.1515/nanoph-2021-0458.
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Abstract The insight that optical vortex beams carry orbital angular momentum (OAM), which emerged in Leiden about 30 years ago, has since led to an ever expanding range of applications and follow-up studies. This paper starts with a short personal account of how these concepts arose. This is followed by a description of some recent ideas where the coupling of transverse orbital and spin angular momentum (SAM) in tightly focused laser beams produces interesting new effects. The deflection of a focused light beam by an atom in the focus is reminiscent of the Magnus effect known from aerodynamics. Momentum conservation dictates an accompanying light force on the atom, transverse to the optical axis. As a consequence, an atom held in an optical tweezer will be trapped at a small distance of up to λ/2π away from the optical axis, which depends on the spin state of the atom and the magnetic field direction. This opens up new avenues to control the state of motion of atoms in optical tweezers as well as potential applications in quantum gates and interferometry.
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Lorberbaum, David S., and Scott Barolo. "Gene Regulation: When Analog Beats Digital." Current Biology 23, no. 23 (December 2013): R1054—R1056. http://dx.doi.org/10.1016/j.cub.2013.10.004.
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Garzia, I., M. Alexeev, A. Amoroso, R. Baldini Ferroli, M. Bertani, D. Bettoni, F. Bianchi, et al. "GEM detector performance with innovative micro-TPC readout in high magnetic field." EPJ Web of Conferences 170 (2018): 01009. http://dx.doi.org/10.1051/epjconf/201817001009.
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Gas detector development is one of the pillars of the research in fundamental physics. Since several years, a new concept of detectors, called Micro Pattern Gas Detector (MPGD), allowed to overcome several problems related to other types of commonly used detectors, like drift chamber and micro strips detectors, reducing the rate of discharges and providing better radiation tolerance. Among the most used MPGDs are the Gas Electron Multipliers (GEMs). Invented by Sauli in 1997, nowadays GEMs have become an important reality for particle detectors in high energy physics. Commonly deployed as fast timing detectors and triggers, their fast response, high rate capability and high radiation hardness make them also suitable as tracking detectors. The readout scheme is one of the most important features in tracking technology. Analog readout based on the calculation of the center of gravity technique allows to overcome the limit imposed by digital pads, whose spatial resolution is limited by the pitch dimensions. However, the presence of high external magnetic fields can distort the electronic cloud and affect the performance. The development of the micro-TPC reconstruction method brings GEM detectors into a new prospective, improving significantly the spatial resolutionin presence of high magnetic fields. This innovative technique allows to reconstruct the 3-dimensional particle position, as Time Projection Chamber, but within a drift gap of a few millimeters. In these report, the charge centroid and micro-TPC methods are described in details. We discuss the results of several test beams performed with planar chambers in magnetic field. These results are one of the first developments of micro-TPC technique for GEM detectors, which allows to reach unprecedented performance in a high magnetic field of 1 T.
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Davoudi, Rouzbeh, Gregory R. Miller, Paolo Calvi, and J. Nathan Kutz. "Computer vision–based damage and stress state estimation for reinforced concrete and steel fiber–reinforced concrete panels." Structural Health Monitoring 19, no. 6 (December 17, 2019): 1645–65. http://dx.doi.org/10.1177/1475921719892345.
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This article presents a computer vision damage assessment approach that relates surface crack patterns to damage levels and stress state characteristics in conventionally reinforced concrete and steel fiber–reinforced concrete panels. Previous studies have focused on crack patterns for specific structural element types such as beams and columns, but this study considers stress states in a more general framework. In particular, image data from previously published panel test specimens subjected to nominally constant stress have been collected to develop image-based estimation models capable of quantifying damage levels and stress components for full-panel crack patterns, and to investigate subimage sampling strategies to approximate full-panel results using partial-panel images. The objective here is to show that the analog of representative volume elements can be extended to image-based analysis contexts. The image datasets used in this article have been obtained from five different published studies, which provided 189 crack pattern images captured from [Formula: see text] concrete and steel fiber–reinforced concrete shear panel specimens. Given the limited size of the dataset, a feature-based computer vision approach has been used, with various geometric attributes of surface crack patterns used to train the estimation models. Within the limits of the data available, the preliminary results presented here indicate that quantifiable correlations exist such that stress state and damage level estimation models are valid across a range of loadings (i.e. reverse cyclic and monotonic) and materials (reinforced concrete and steel fiber–reinforced concrete), and that with appropriate sampling techniques, it is possible for subsampled images to yield estimations similar to full-panel results. These localized correlations between crack patterns and stress states potentially could be used in broader contexts for damage assessment of more general reinforced concrete and steel fiber–reinforced concrete members.
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Ambrosini, D., A. Ponticiello, G. Schirripa Spagnolo, R. Borghi, and F. Gori. "Bouncing light beams and the Hamiltonian analogy." European Journal of Physics 18, no. 4 (July 1, 1997): 284–89. http://dx.doi.org/10.1088/0143-0807/18/4/008.
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Teodorescu, P. P., and Ileana Toma. "On the analogy between deflected elastic beams and deflected relativistic electron beams." Mechanics Research Communications 13, no. 5 (September 1986): 265–70. http://dx.doi.org/10.1016/0093-6413(86)90067-4.
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Rybakov, Vladimir, and Alexander Sergey. "Mathematical Analogy between Non-Uniform Torsion and Transverse Bending of Thin-Walled Open Section Beams." Applied Mechanics and Materials 725-726 (January 2015): 746–51. http://dx.doi.org/10.4028/www.scientific.net/amm.725-726.746.
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The objective of this work is to identify and make an analysis of correlation between functions of bimoments and function of bending moments arising in the beams under the same loads. This article shows the possibility of using a diagram of bending moment multiplied by a factor as a diagram of bimoment. The maximum deviation between diagram of bending moment and diagram of bimoment made up 3.6 % of maximum bending moment in case of uniformly distributed load on one side of fixed supported beam.
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Baranets, N. V., Yu Ya Ruzhin, and J. Vojta. "Wave-particle interaction during electron beam-modulated injection into the ionospheric plasma. Theory and experiment." Kosmìčna nauka ì tehnologìâ 27, no. 6 (2021): 16–37. http://dx.doi.org/10.15407/knit2021.06.016.
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We present the results of the active space experiment with charged particle beam's injection (electrons and xenon ions) carried out onboard Intercosmos-25 station and daughter Magion-3 subsatellite. The ones are obtained under conditions when the particle beams were injected in opposite directions relative to the magnetic field B0 in such a way that the electron injection was directed towards the Earth. Mechanisms of beam-plasma instabilities relative to the excitation of electrostatic and electromagnetic waves are considered during the electron beam injection (~10 keV, 0.1 A) from the Intercosmos-25 station. Development of transverse instability on the first cyclotron resonance leads to the excitation of whistler mode waves backward-propagating relative to the injected electrons (from the Earth). The investigation object was the beam-excited differential fluxes of ionospheric electrons in a wide energetic range of 27 eV — 412 keV registered by the charged particle spectrometers onboard the Magion-3 subsatellite. Thereby, the interaction of whistler waves with ionospheric electron fluxes is stimulated by the energy transfer mechanisms such as 'particle-wave-particle'. Numerical results of beam-plasma instabilities are compared also with thermal plasma parameters registered at different space points on the station and subsatellite. Excitation of longitudinal and transverse beam-plasma instabilities will inevitably lead to their competition, which will affect the results of the experiment. The data of stimulated fluxes of ionospheric electrons allow us to investigate the various effects of the wave-particle interaction, taking into account the influence of the growth rate of longitudinal instability on the excitation angle of whistlers and their structure. This approach is based on the results of laboratory experiments to determine the pattern of excited whistlers for an electric dipole antenna and the analogy of the beam-plasma channel with the radiating system. The results of the active space experiment confirm the dependence of the growth rate of whistler mode waves on the development of longitudinal beam instability.
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Gong, Zhixiong, and Michael Baudoin. "Single focused-beam acoustical tweezers." Journal of the Acoustical Society of America 151, no. 4 (April 2022): A121. http://dx.doi.org/10.1121/10.0010845.
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Single beam acoustical tweezers have seen rapid development for their potential applications in vitro and in vivo in different fields such as acoustofluidics, microrobotics, precision medicine, and so on. The first single beam acoustical tweezers used a focused beam in analogy with optical tweezers [Lee et al., Appl. Phys. Lett., 95, 073701 (2009)]. However, they only succeeded to trap light particles with negative acoustic contrast factor in two dimensions. In this talk, we revisit theoretically the capabilities of acoustical tweezers based on focused beams and demonstrate that they can trap (i) some specific light elastic particles and droplets in three dimensions in and beyond the Rayleigh regime, (ii) dense particles (with positive acoustic contrast factor) in two dimensions near the resonance frequencies, and (iii) lipid cells in three dimensions. Some preliminary experimental results will be presented.
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De Rosa, M. A., M. Lippiello, G. Armenio, G. De Biase, and S. Savalli. "Dynamic analogy between Timoshenko and Euler–Bernoulli beams." Acta Mechanica 231, no. 11 (August 31, 2020): 4819–34. http://dx.doi.org/10.1007/s00707-020-02795-4.
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Czyczula, Wlodzimierz, Piotr Koziol, and Dorota Blaszkiewicz. "On the Equivalence between Static and Dynamic Railway Track Response and on the Euler-Bernoulli and Timoshenko Beams Analogy." Shock and Vibration 2017 (2017): 1–13. http://dx.doi.org/10.1155/2017/2701715.
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The paper tries to clarify the problem of solution and interpretation of railway track dynamics equations for linear models. Set of theorems is introduced in the paper describing two types of equivalence: between static and dynamic track response under moving load and between the dynamic response of track described by both the Euler-Bernoulli and Timoshenko beams. The equivalence is clarified in terms of mathematical method of solution. It is shown that inertia element of rail equation for the Euler-Bernoulli beam and constant distributed load can be considered as a substitute axial force multiplied by second derivative of displacement. Damping properties can be treated as additional substitute load in the static case taking into account this substitute axial force. When one considers the Timoshenko beam, the substitute axial force depends additionally on shear properties of rail section, rail bending stiffness, and subgrade stiffness. It is also proved that Timoshenko beam, described by a single equation, from the point of view of solution, is an analogy of the Euler-Bernoulli beam for both constant and variable load. Certain numerical examples are presented and practical interpretation of proved theorems is shown.
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Gahleitner, Johannes, and Hans Irschik. "Extension of Boley’s continuum mechanics-based successive approximation method to two-layer rectangular beams." Continuum Mechanics and Thermodynamics 33, no. 4 (April 5, 2021): 1709–31. http://dx.doi.org/10.1007/s00161-021-01003-5.
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AbstractAn extension of Boley’s continuum mechanics-based successive approximation method is presented for rectangular beams composed of two isotropic linear elastic layers. The solution is cast into the form of tables, in complete analogy to the tables originally presented by Boley and Tolins for single-layer strips. The first column in these tables corresponds to the classical Bernoulli–Euler theory of beams. The further columns represent comparatively fast converging correction terms of an increasing refinement. Our two-layer formulation automatically satisfies the stress continuity conditions at the interface of the two layers. Enforcing displacement continuity at the interface between the layers, we derive results that do satisfy the equilibrium field equations, the stress continuity conditions at the interface and the stress boundary conditions at the upper and lower edges. When converged, the field constitutive relations and the displacement continuity at the interface between the two layers are also satisfied. We present a compact formulation, which allows writing down the results for more than the three successive steps considered by Boley and Tolins. The elasticity solutions presented subsequently can be used as novel analytic benchmarks for comparison with refined structural mechanics beam theories. Interior solutions for beams with a finite axial extent can be obtained by assigning approximate boundary conditions at the lateral ends. Comparisons to finite element computations for a clamped–clamped beam give strong evidence for the correctness of our analytic results.
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Knox, Ethan, and P. T. Leung. "Constraints on the reciprocal propagation of a quantum particle through a one-dimensional localized complex potential." Canadian Journal of Physics 91, no. 3 (March 2013): 246–50. http://dx.doi.org/10.1139/cjp-2012-0459.
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In the propagation of an electron through a one-dimensional asymmetric complex potential, it is known that while the conventional Green function reciprocity symmetry will ensure transmission to be symmetric between a “left-incident” and a “right-incident” beam, no such symmetry exists for the case of reflection. Here we derive generalized reciprocity relations for both the amplitude and phase of the reflected waves as constraints on the left- and right-incident beams, in complete analogy to what was established in optics. We further provide illustrations of these relations via direct analytical calculations in the case of a real potential, and via numerical studies in the case of a complex potential.
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Andika, Ari, Feri Kusnandar, and Slamet Budijanto. "KARAKTERISTIK FISIKOKIMIA DAN SENSORI BERAS ANALOG MULTIGRAIN BERPROTEIN TINGGI." Jurnal Teknologi dan Industri Pangan 32, no. 1 (June 2021): 60–71. http://dx.doi.org/10.6066/jtip.2021.32.1.60.
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Several grains (green bean, red bean, soybean, corn, nuts, sesame, and millets) were processed to yield a high protein analogue rice. Red beans and green beans were soaked in water for six hours while soybean was boiled for 10 minutes and then peeled. Nuts were dried at 70°C, ground, and sieved to pass 80 mesh. All grains were ground into powder except for sesame which was in whole seed. Four formulas of rice analogues were produced at a different level of millet (0-15%), corn (35-50%) with fixed level of red beans (10%), soybeans (25%), green beans (10%), sesame (3%), and glycerol monostearate (GMS) (2%). The products were analyzed in terms of proximate composition, hardness, water absorption index, development ratio, cooking time, in vitro protein digestibility, amino acids composition, and protein digestibility-corrected amino acid score (PDCAAS). The four analogue rice formulas contained high level of protein and protein digestibility, but they did not fulfill the targeted complementation. The protein content of the analogue rice varied from 18.19 to 19.09% (wet based) with protein digestibility of 81.27-88.86%. The most preferred formulas of the rice analogue was composed of corn (40%), millet (10%, red beans (10%), soybeans (25%), green beans (10%), sesame (3%), and GMS (2%). It contained 42.48% of amino acids score and 36.53% of PDCAAS value.