Theoretical Mode Research Articles

Frequency-diverse multimode millimetre-wave constant-\u03f5r lens-loaded cavity

This paper presents a physical frequency-diverse multimode lens-loaded cavity, designed and used for the purpose of the direction of arrival (DoA) estimation in millimetre-wave frequency bands for 5G and beyond. The multi-mode mechanism is realized using an electrically-large cavity, generating spatio-temporally incoherent radiation masks leveraging the frequency-diversity principle. It has been shown for the first time that by placing a spherical constant dielectric lens (constant-ϵr) in front of the radiating aperture of the cavity, the spatial incoherence of the radiation modes can be enhanced. The lens-loaded cavity requires only a single lens and output port, making the hardware development much simpler and cost-effective compared to conventional DoA estimators where multiple antennas and receivers are classically required. Using the lens-loaded architecture, an increase of up to 6 dB is achieved in the peak gain of the synthesized quasi-random sampling bases from the frequency-diverse cavity. Despite the fact that the practical frequency-diverse cavity uses a limited subset of quasi-orthogonal modes below the upper bound limit of the number of theoretical modes, it is shown that the proposed lens-loaded cavity is capable of accurate DoA estimation. This is achieved thanks to the sufficient orthogonality of the leveraged modes and to the presence of the spherical constant-ϵr lens which increases the signal-to-noise ratio (SNR) of the received signal. Experimental results are shown to verify the proposed approach.

Research on the Training Mode of Product Design Talents Based on the Mode of Sino Foreign Cooperation in Running Schools

As an application-oriented major with strong practicality, product design specialty is oriented to cultivate compound senior professional and technical talents with solid scientific and technological foundation and artistic innovation ability, and pays attention to the system technology of efficiency and benefit research. Practice teaching occupies a large proportion for the traditional "inculcation" theoretical teaching mode has been unable to meet the needs of talents in the rapid changing of the market. At present, under the mode of Sino foreign cooperation in running schools, the effective integration of international talent outlook, quality views and high-quality education resources at home and abroad has greatly improved the quality and level of training for product design talents. This paper focuses on the issues related to the training mode of product design talents under the mode of Sino foreign cooperation in running schools.

Theoretical Mode and Implementation Path of Cultural and Creative Product Development in Public Libraries

Theoretical Mode and Implementation Path of Cultural and Creative Product Development in Public Libraries

Mathematical modeling of the electronic structure of Titanium dioxide \((TiO_2 )_6\) nanoparticles

The calculation of the number of atoms of the given dimensional nanoparticle, composed of different type atoms has been researched in this work. The calculations have been carried out for nanoparticles of titanium dioxide. Theoretical visual models have been configured, and quantum – mechanical calculations have been carried out for \((TiO_2 )_6\) nanoparticle. The calculations for titanium dioxide nanoparticle have been carried out on the basis of Gaussian atomic orbitals. Besides, Gaussian functions have been used as atomic orbitals. The numerical values of unknown coefficients of the linear combination of atomic orbitals of the atoms of the titanium nanoparticle have been found from the solution of Hartree–Fock–Roothaan (HFR) equations.The values of orbital energies, ionization potential, and the total electronic energy of titanium dioxide nanoparticles have been determined. The calculations show that ,titanium dioxide nanoparticle is tough, electrophile, and stable dielectric, material. The effective charge of atoms have been calculated, and the theoretical visual mode of titanium dioxide nanopartical have been constructed.

Experiments on laminated bamboo lumber nailed connections

Laminated bamboo lumber (LBL) nailed connection made with LBL main member and sandwiched by LBL side members is introduced, which plays an essential role in the safe and reliability of bamboo buildings. However, little research attention has been paid on to the mechanical behavior of connections. This paper reports an experimental study on the effect of parameters on reference loads (yield load and maximum load), stiffness and load-slip behavior of the connections, including nail diameter, number of lines and rows of nails. For single nail connection, nail pull-through and plastic hinges forms in LBL members. Mode cross-over from ductile response to brittle failure is observed in multi-nail connections with one or more splitting cracks develop from the nails hole edges toward the ends of the side or middle members. A decreasing ductility of connections is investigated with increasing diameter and number of nails. The capacity of effective number of nails in a row is evaluated and compared with that obtained from existing analytical formulas. Predictions from existed various theoretical modes are compared with experimentally determined capacities of nailed connection per shear plane per nail and conclude that the load carrying capacity of connections with laterally load nails can be applied to accurately estimate using European yield models (EYMs). Furthermore, the model developed by Folz is capable of predicting the load-slip relationship of LBL nailed connections. The findings of this study will provide the scientific basis and useful information for the design and finite element numerical simulation of engineered bamboo structures containing LBL nailed connections and promote the rational use of bamboo resources in the field of civil engineering.

Nonlinear optical properties and spectroscopic characterization of Y-shaped polymer using quantum chemical approach.

The present study reports nonlinear optical properties such as the first and second hyper polarizabilities (β and γ) of Y-shaped polymer (P1) and substituted polymers. The basic Y-shaped polymer (R = R1 = H) was named as P1. Upon substitution of one OCH3 group in ortho position of oxygen, it becomes polymer P2 (R1 = H, R = OCH3) and other OCH3 group on another ortho becomes P3 (R1 = R = OCH3). We have also reported structural parameters, vibrational and electronic absorption spectra of polymer, and its substituted polymers. The geometrical parameters such as dipole moment, bond length, and angles are reported at B3LYP/6-311++g** level of theory. In addition, the vibrational, electronic absorption spectra and nonlinear optical (NLO) properties are also reported at the same level of theory. There is a significant change in dipole moment and in energy observed whereas symmetry, bond length, and angles are resembling Y-shaped and substituted polymer. The vibrational spectra of Y-shaped polymer (P1) having the intense peak are C-H stretching mode observed at 1258cm-1. These theoretical vibrational modes are well matching with available experimental determinations. The method dependent hyperpolarizabilities calculated by applying the field along the X, Y, and Z direction. This study confirms the polymer P1 and P2 showing first and second hyperpolarizability response whereas P3 do not show. The electronic absorption spectra for polymer and substituted polymers are also reported at the same level of theory using (TDDFT) approach. The wavelength of electronic transition, oscillator strength, and HOMO-LUMO gap was also reported.

Vibro-acoustic characteristics of eccentrically stiffened functionally graded material sandwich cylindrical shell under external mean fluid

The main objective of this research work is focused on acoustic radiation analysis of functionally graded material (FGM) sandwich cylindrical shell structure reinforced by periodically eccentrically ring stiffeners. In the analysis, two common types of FGM sandwich cylindrical shell are considered, which include one with FGM face shell and homogeneous ceramic or metal core, and the other with FGM core and homogeneous face shell. Given the structure is immersed in a mean flowing fluid of velocity tangential to the accoustically deformed boundary and it is excited by a radial point force. The ring stiffeners are assumed to be identical and uniformly spaced, and the in-plane flexural and out-of-plane torsional motions of the ring stiffeners are employed to accurately describe the force moment coupling between the stiffeners and the shell. Fluid-structure coupling is considered by imposing velocity continuity condition at fluid-structure interfaces. By applying the Poisson summation formula and the Fourier transformation technique for periodic ring stiffeners FGM shell structures, the sound pressure level (SPL) about structural acoustic radiation performance index is expressed in a superposition form of space harmonics for a given wave number. The validity of the proposed theoretical model is verified by comparisons with previously published numerical results. Based on the developed theoretical mode, the influences of the FGM properties, gradient index, sandwich type, the size of ring stiffener, external mean flow and skin-core-skin ratios type on the structural acoustic radiation performance have been investigated. In addition, the results show that under the same skin-core-skin ratio and thickness, the acoustic radiation performances of type C seem better, and the larger the section size of ring stiffened, the greater the influence of structure acoustic radiation characteristics, whereas the magnitudes of the SPL curves increase with the increasing values of Mach number.

An experimental approach to improve creative skills of Advertising design Students

The experimental approach is one of the recent trends adopted by the standards of the quality assurance and teaching system where it depends on considering that the expected outputs and skills to be acquired can only be achieved through practical experience. The experimental approach focuses on the necessity of analyzing educational systems into practical methods that develop students' intellectual and sensory skills in a positive way of learning and interacting with theoretical modes Which the teacher seeks to apply in modern scientific and technological methods, which requires setting future visions that help raise the indicators of the performance of teaching and learning methods. And from here the importance of virtual learning appeared in the teaching of advertising design where the learner involved in his learning that the learner is an active participant who conducts discussions, research and experimentation. As for the teacher, he is the mentor and guide for learning so that the situation is managed intelligently. Advertising design is a coherent system that works as one unit that is dealt with within the framework of a comprehensive view of all its stages Where the method of learning design depends on establishing the conceptual structure of specialization with the aim of developing the cognitive, creative, sensory and intellectual aspects of a student who is at the core of advertising, in addition to achieving targeted educational behaviors. Therefore, the research problem arises in how to activate the experimental approach in teaching the design of advertising to enrich and support the expected outputs and creative skills acquired by the student of advertising design. The research aims to apply the comprehensive quality standards for educational programs by activating the experimental curriculum as one of the educational curricula to develop the creative and intellectual skills of the advertising department student. The applied study tries to enhance the experimental approach to teaching advertising, and this is done through a project that was presented to students of the High Institute of Applied Arts - 6th of October City (a mythical object) where it 'leaves them free to choose graphic elements through (human element - plant element - animal component - Inanimate) to attract targeted recipients through Brainstorming sessions, in addition to visiting the printing presses to learn about printing technology and then reaching the results of the study, the most important of which is that the experimental approach works to develop the cognitive, creative, sensory and intellectual aspects of a student advertising designer, in addition to Achieve targeted educational behaviors

Research on Teaching Strategy of Roadbed Structure and Construction Course Based on BIM Technology

The roadbed structure and construction course is a compulsory course for the major of road and bridge engineering technology in higher vocational colleges. The content of the course is theoretical, the formula is complex, and it is difficult to understand, which increases the difficulty of students’ learning, especially under the traditional “indoctrination” theoretical teaching mode , Classroom teaching efficiency is low, and students tend to lose interest and confidence in learning. With the application of BIM technology, students were visually shown the relationship between subgrade structure and construction components and construction links, with remarkable results. This article focuses on the problems related to the teaching of roadbed structure and construction courses based on BIM technology.

Comparison of high resolution mrm and sequential window acquisition of all theoretical fragment-ion acquisition modes for the quantitation of 48 wastewater-borne pollutants in lettuce

Screening of a large number of chemicals of emerging concern is highly desirable for the control of crops irrigated with reclaimed water since it is considered an alternative water source of great value. This study describes a high resolution mass spectrometry approach for developing methods for quantification in lettuce leaves of 48 different wastewater-borne pollutants (including analgesics and anti-inflammatories, anti-hypertensives, antifungal agents, lipid regulators, psychiatric drugs and stimulants, β-blockers, antibiotics, antimycotics, and sweeteners) frequently found in water resources. In this respect, a simple and fast QuEChERS-based method for the determination of contaminants in lettuce has been developed. During extraction, the use of formic acid was adopted to further improve the results of some problematic compounds (e.g., fenofibrate, furosemide, metronidazole, oxcarbazepine, sulfanilamide). High resolution multiple reaction monitoring (MRMHR) and SWATH acquisition were compared in term of accuracy, repeatability, sensitivity, linearity and matrix effect. Both methods provided similar recoveries between 80 and 120% in lettuce leaves, although sulfanilamide, ciprofloxacin, and sulfamethazine presenting values of 26.8, 27.8, and 28.4% in MRMHR and 25, 33.9, and 35% in SWATH, respectively. The effectiveness of a two-step cleanup on analyte recovery was also assessed and matrix effects were also taken into consideration during the method validation. The developed method allows the simultaneous quantitative analysis of 48 compounds (drug residues and metabolites) in lettuce leaves irrigated with treated wastewater for human consumption. Application of the present method to lettuce crops growth in controlled conditions showed the presence of 14 out 48 studied compounds with similar concentrations in both acquisition modes ranging from 3.3 and 1.3 ng g − 1 for climbazole (for MRMHR and SWATH, respectively) to 33.2 and 17.7 ng g − 1 for sulfamethazine. Drug residues such as carbamazepine (6.0 and 8.5 ng g − 1), and its metabolite carbamazepine epoxide (18.1 and 16.5 ng g − 1), frequently found in wastewater effluents, were also detected.

Towards understanding of different solid forms of formoterol fumarate: Combined computational and experimental approach

In this study, specimens of Formetrol fumerate were investigated using IR and Raman vibrational spectroscopy as well as quantum chemical calculations. The structure of formetrol fumerate was optimised using density functional theory calculations and the geometry optimization has been carried out on three different solvate crystal forms; di-hydrate, di-ethanolate, and di-isopropanolate in addition to the anhydrate form with and without intramolecular hydrogen bonding. Molecular assignments are proposed on the basis of ab initioB3LYP DFT calculations with a 6–31 G∗ basis set and vibrational wavenumbers. Crystallographic investigation has been carried out to formetrol anions and protonated anions arising from crystal structures of the studied conformers and it was evidenced that the di-hydrate form has the highest energy probably due to the greater possibility of intramolecular hydrogen bonding. Infrared and Raman spectra were calculated from the optimised structures. Many modes in the calculated spectra were matched with the experimental spectra and a description of the modes was given. By analysis of the theoretical vibrational modes, it was proved that formetrol fumerate specimens are likely to be dihydrate form with and without intramolecular hydrogen bonding. Additionally, several spectral features and band intensities in the stretching and bending regions were explained. Quantum mechanical calculations allowed improved understanding of formetrol fumerate and its vibrational spectra as an important β2 antagonistic compound in various pharmaceutical formulations. The obtained data could provide useful information about its interactions with excipients and other components.

Fe-doped Na0.47Bi0.47Ba0.06Ti0.98-xV0.02FexO3: Structure correlated vibrational, optical and electrical properties

Structural, optical, and electrical properties of rhombohedral (R3c) Fe-doped Na0.47Bi0.47Ba0.06Ti0.98-xV0.02FexO3 (x = 0, 0.005 and 0.01) are reported. The bond-lengths and bond angles were studied and were correlated with the vibrational, optical, and electrical properties of the materials. Oxygen displacement, Ti off-centering and tilting of octahedra are discussed and correlated with the optical/electronic properties. The theoretical phonon modes of NBT calculated from DFT analysis were correlated with the experimentally observed phonon modes for the three samples. The dielectric properties were explored along with the ferroelectric properties. High temperature phase transitions were analyzed leading from a ferroelectric phase at room temperature to an antiferroelectric phase at ∼200 °C and further to a paraelectric phase at ∼400 °C. The phase transition temperatures vary from sample to sample and can be the disorderness of the A/B site cations. The energy storage efficiency varied with the structural changes and was found to be maximum for the 0.5% doped Fe(S2).

Tunnel image stitching based on geometry and features

In the fast tunnel detection of multi-camera, a disease distributed in multiple images is prone to be misidentified as multiple diseases, which affects the evaluation of the status of the tunnel. This paper proposes a high-precision stitching method driven by data and scene based on multi-camera sequence images. Firstly, geometric rough calculation is performed to generate the theoretical stitching mode using the geometric positional relationship between the cameras in the scene and the image relationship is renewed after theoretical stitching. Secondly, feature points are extracted and matched for adjacent overlapping images by SURF algorithm. Therefore, pixel-level data registration is performed to achieve the image stitching. Finally, an integrated stitching mode is proposed based on the theoretical stitching and pixel-level data registration, which utilizes the stitched sequence images with high physical resolution to extract cross-section information. Practical results show that the method can achieve image stitching of the tunnels with high accuracy and good reliability.

The Cybernetic Victorians

The Cybernetic Victorians

Analysis of Superconductor of Nd1Ba2Cu3O7 and Nd3Ba5Cu8O18 Phases Using FTIR Spectrophotometer

I has been synthesized superconducting materials of the Nd1Ba2Cu3O7, Nd3Ba5Cu8O18 and Y3Ba5Cu8O18 phases. The study was conducted to determine whether the data from the phase Y1Ba2Cu3O7 can be used as a base to identify superconducting material of the Nd3Ba5Cu8O18 phase. Synthesis was done by solid state reaction method with initial mixing in HNO3 solution mixture with Y2O3, Nd2O3, BaCO3, and CuO, with the ratio adjusted to the stoichiometry calculation. Samples in the form of pellets with a diameter of 1.5 cm were sintered at 950 oC for 24 hours in an atmospheric environment. The FTIR measurements have been carried out with a standard KBr. The theoretical calculation spectra and vibration mode data from YBa2Cu3O7-d can be used to identify Nd1Ba2Cu3O7, Nd3Ba5Cu8O18 dan Y3Ba5Cu8O18, with peak absorption in the range of wave numbers that are almost the same, namely 400-450 cm-1, which is the four oxygen atoms O(2,3) mode, 426-439 cm-1 is the in-phase mode of oxygen atom O(2,3), and the vibrational mode of peaks O(4) is observed at 488 cm-1.

Exploring the Influence of Learning Motivation and Socioeconomic Status on College Students' Learning Outcomes Using Self-Determination Theory.

Higher education, which has the function of cultivating human capital, has already become a key focus of developed countries around the world. From ministries of education to higher education institutions, many bodies are dedicated to enhancing student learning outcomes. However, social and educational problems derived from disadvantaged groups have long been hindering the development of individuals and the whole country. This study examines the learning motivations of economically disadvantaged versus non-disadvantaged college students and evaluates the relationship between learning modes and learning outcomes from a self-determination theory (SDT) perspective. In this study, 817 valid questionnaires were collected to compare the two sample groups in terms of learning path. The results show that non-economically disadvantaged students have superior outcomes compared to disadvantaged students in terms of role identity, academic identity, explorative learning, exploitative learning, and cognitive and non-cognitive gains. In regard to path analysis, economically disadvantaged students are significantly superior to non-disadvantaged students in the face of positive influence of academic identity on different learning modes and positive influence of explorative learning on cognitive and non-cognitive gains. Finally, based on the conclusions, this study proposes some suggestions specific to theoretical mode for future study.

Theoretical calculation by Talys code in combination with Geant4 simulation for consideration of [formula omitted] reactions of Eu isotopes in the giant dipole resonance region

In this work, the differential cross-sections of 151Eu(γ,n)150Eu and 153Eu(γ,n)152Eu photonuclear reactions in the giant dipole resonance region (GDR) were considered by theoretical models available in Talys 1.8 code. Isomeric ratios of these two reactions induced by bremsstrahlung with end-point energies in (GDR) region were then simulated using the calculated cross-section in combination with Monte-Carlo simulation using Geant4 toolkit based code which was implemented to simulate bremsstrahlung and photonuclear reaction. Moreover, a simple model was added into Geant4 for populating multi-isomeric states. The theoretical results were compared with the experimental data from the existing literature to examine the validity of the theoretical modes.

Observation of continental shelf wave propagating along the eastern Taiwan Strait during Typhoon Meranti 2016

This study is the first to depict typhoon-induced continental shelf wave (CSW) propagation in the eastern Taiwan Strait (TWS) during the passage of Typhoon Meranti in 2016 using tidal gauge data and along-track satellite altimeter data. The strong amplitude response of sea level oscillations (within the range of 0.30–0.54 m) as a free, barotropic CSW after Meranti, which impacted the TWS, was clearly detected in time and frequency (in bands of 64–81 h) using wavelet and cross-wavelet analyses. The measured group and phase speeds were consistent with the dispersion curves for CSW with the first-mode derived from the cross-shelf sections of the eastern TWS, with the mean speeds reaching 3 and 5.6±0.7 m/s, respectively. Coincidentally, the typhoon-induced sea level anomaly (SLA) was also captured by the satellite altimeter before this CSW entered into the TWS. Using the theoretical cross-shore CSW modes to fit the SLA data, the results indicated that the first three wave modes can interpret this CSW event appeared in the southern TWS very well, with the first mode being the dominant one.

Energy related model correlation criteria for modal analysis of fluid-structure interaction systems

Vibroacoustical problems are sometimes treated by modal analyis, which has been applied to air-filled shells. It is suggested to use the method for various types of liquid-structure interaction systems. Potential applications are water or oil hydraulic pipelines and heavy machinery actuated by fluid power. Modal testing of such systems should be accompanied by sensor placement strategies, test data assessment, and comparisons between theoretical and experimental mode shapes. In structural dynamics, these issues are covered by model correlation criteria like the classical modal assurance criterion (MAC). From the orthogonality relations of undamped vibroacoustical systems, two new criteria are developed. Their respective formulations are related to potential energy (POTMAC) and kinetic energy (KINMAC). Both criteria assume real values between zero and one. In practical applications of model correlation, it should be understood which values are acceptable. An approximation indicates that the limits for individual matrix elements can be adopted from the MAC. Numerical examples of POTMAC and KINMAC matrices are given for two different hydraulic press models. Analogies between POTMAC, KINMAC, and the rotor modal assurance criterion (RMAC) are pointed out. The new criteria can help to develop modal testing into a useful tool for systems with a vibroacoustical model structure.

Study on cantilever piezoelectric energy harvester with tunable function

Piezoelectric energy harvesters tend to convert energy from ambient vibration to electricity, which can gain a higher output voltage at resonance region. How to obtain a larger working bandwidth is urgent to explore at present. In this paper, a cantilever plate energy harvester is designed, with two boxes added at two free edges along the fixed-free direction and one rolling ball placed in each boxes respectively. The natural frequency of the structure can be adjusted by changing the centroid of the structure, which is caused by the balls rolling in the box. The range of adjustment that contains from the maximum (upper limit) to minimum (lower limit) frequency, is defined as the theoretical frequency band. The mode function of tunable cantilever plate is given according to deflection curve. Considering the rigid body motion of boxes and the composite motion of the balls, the Hamilton principle and the Hertz contact theory are taken into account to derive the vibration equations of the system. The experiment is carried out to verify the correctness of the theoretical mode and the dynamic equations. The responses of the structure under different excitation frequencies are calculated by using MATLAB software and verified by frequency sweep experiment. The results show that the working bandwidth of proposed structure under different balls initial positions is wider than with that of beam structure in resonance, thus proving the better tuning ability of the designed system. In addition, the output of the energy harvester under different external excitation acceleration is given. The effects of different length of box on the working bandwidth and output power density are studied. The relationship between conversion rate and external resistance is proposed under different boxes length. A high performance energy harvester with wider operating frequency range is designed.