Focusing Phenomenon Research Articles

Analysis of Driving Factors of Photovoltaic Power Generation Efficiency: A Case Study in China

With the increasing consumption of fossil energy and changes in the ecological environment, meeting the energy demands required for industrial and economic development with clean and efficient power generation is a major challenge of our society. Solar energy is considered to be one of the most renewable and sustainable energy sources, and photovoltaic power generation has become an important research topic. This study combines data envelopment analysis (DEA) with Tobit regression analysis to assess the efficiency of photovoltaic power generation in China and analyze factors affecting efficiency to improve the efficiency of photovoltaic power generation. The results show that there are obvious regional differences in photovoltaic power generation efficiency in China. The phenomenon of focusing on economic development at the expense of the use of solar power generation still exists. The establishment of photovoltaic demonstration projects, the implementation of differential electricity price policies, and the promotion of photovoltaic precision poverty alleviation can alleviate economic pressure and effectively improve the efficiency of photovoltaic power generation.

Acoustic Transmission Characteristics Based on H-Type Metamaterials

To achieve the artificial manipulation of the acoustic wave front, and to produce high-efficiency acoustic focusing effect, this paper designed an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$H$ </tex-math></inline-formula> -type locally resonant metamaterial structure based on a two-dimensional three-component local resonance unit. The transmission characteristics of acoustic waves in this model were analyzed by using COMSOL, which is a finite element simulation software. We found that the incident acoustic energy was absorbed by the model, and the transmission path was consistent with the model structure. We also found that in different frequencies, the transmission characteristics of acoustic waves were different. The acoustic transmission characteristics improved as the waves approached the resonant frequency. Because of the flexibility and controllability of metamaterials, the structure can be designed according to specific conditions in practical applications to meet the resonant frequency required for transmitting acoustic signals, thus, improving the acoustic transmission efficiency. In addition, if the point excitation source of spherical waves was replaced by the line excitation source of plane waves, a plane acoustic wave focusing phenomenon would occur, which further proved that the local resonance acoustic metamaterial has good focusing characteristics and manipulation characteristics. The result of our research provides a new direction for underwater acoustic imaging, acoustic communication, and acoustic detection.

Study on the propagation properties of TM electromagnetic wave in Lossy left‐handed material based on CUDA‐implemented parallel

By using the method of Finite Difference Time Domain (FDTD) and the technology of Compute Unified Device Architecture (CUDA), the propagation characteristics of electromagnetic waves in Left-Handed Materials (LHM) have been studied in this paper. The LHM slab was matched with the free space and the secondary focusing phenomenon of LHM was simulated. Compared with the serial FDTD program, our work showed that this method had a high accuracy. The phase compensation effect and the inverse Snell effect of LHM were also discussed by using the parallel FDTD method based on CUDA, which further proved that our results were consistent with the theoretical study. By comparing the calculation time of traditional FDTD program with that of the CUDA based parallel FDTD program, we conclude that the latter is more efficient than the former. This parallel method can be used as a more efficient way to study LHM.

Viittomakielet hybridisysteemeinä - hämärärajaisuus ja epäkonventionaalisuus osana viittomakielten rakennetta

Tässä artikkelissa tarkastellaan hämärärajaisuutta ja epäkonventionaalisuutta osana joitakin kaikista viittomakielistä löydettyjä yksiköitä ja rakenteita ja niiden käyttöä. Täsmällisemmin artikkelin fokuksessa ovat tietyt muodoltaan ja merkitykseltään tilanteisesti muuntuvat viittomat (erityisesti niin kutsutut osittain leksikaaliset viittomat) sekä eräänlainen vaihteleva-asteinen näytteleminen (niin kutsuttu konstruoitu toiminta), jota viittojat käyttävät tuottamiensa syntaktisten rakenteiden osana ja niiden sijaan. Käytännössä artikkeli esittelee näkemyksen, jonka mukaan molemmissa tarkastelun kohteena olevissa ilmiöissä on kyse samasta asiasta eli kielen diskreettien ja konventionaalisten ominaisuuksien sekoittumisesta hybridiluonteisesti kieleenkuuluvien hämärärajaisten ja epäkonventionaalisten ominaisuuksien kanssa. Artikkeli pohtii lyhyesti myös puhuttujen kielten luonnetta hybridisysteemeinä.

Musical co-creativity and learning in the Kokas pedagogy: Polyphony of movement and imagination

The study reported here is part of a research collaboration with the Kodály Institute of the Liszt Academy of Music. Our research centres around the Kokas pedagogy, an experiential approach to music education combining music, movement and reflection. The paper contributes the Higher Education research strand, unpacking the relevance of this pedagogy in the context of music teacher education. Returning to the phenomenological roots of dialogicality (Merleau-Ponty, 1968; Buber and Gregory Smith, 1958) and drawing on the key principles of Natural Inclusionality (Rayner, 2017) it investigates the nature and value of the embodied musical learning and co-creativity in this context. My aim was to capture the participants’ imaginative re-opening to self and world, expressed through i) synchrony between movement and music, ii) other-orientation, and iii) creative attunement, evolving from the former two. Using video recordings of the focal cohort (9 3-hour sessions with 10 students) and students’ self-reflective compositions, the study involved the qualitative analysis of action (movement data) and reflection. The analytic process combined the researcher’s inner and outer perception in exploring the nature of the phenomena in focus. The findings captured the infinitude of dialogic connectivity in the focal student cohort. The deep cohesion was largely experience-generated, whereby the participants’ awareness was gradually brought back to natural continuity through a fluid, mutually receptive-responsive bodily dialogue. This signifies learning which reaches beyond the knowledge and praxis of intellectually constituted thought and language. The musical encounters proved to be the fountain of new, creative forms of perceiving, knowing and relating in the observed HE setting.

Aperiodic Vogel spirals for broadband optical wave focusing.

We demonstrate both experimentally and numerically a new type of hole array structure that exhibits optically diffractive focusing phenomenon. The hole arrays are designed based on the aperiodic Vogel spirals. In contrast to periodic and quasi-periodic hole arrays that contain discrete Bragg peaks in reciprocal space, the Vogel spiral hole arrays have particularly continuous Fourier components with circular symmetry, which enables optical wave focusing into a diffraction-limited hotspot for a wide range of incident wavelengths. We further demonstrate that the diffracted fields contain local orbital angular momentum (OAM) leading to rotations of the diffractive circular rings around the center, although the total OAM is zero.

VALUES, SIGNIFICANCE AND MOTIVATION AT WORK OF PRISON OFFICERS OF TWO DETENTION CENTERS IN BRAZIL

The constructs values, significance of work and motivation represent key aspects to be considered in the career of any professional. In this study, the researchers’ interest was focused on detention officers working in prisons in the state of Santa Catarina, Brazil. Chiefly, the study aimed to investigate the prison officers’ values, motivation, significance of work based on their viewpoints. The study had 137 participants, of which 36 were female officers and 101 male officers. The methodological design of this research characterizes it as an applied, cross-sectional, descriptive, and quantitative survey. The instruments for data collection were the following: a sociodemographic questionnaire developed by the researchers for characterization of the sample; the Work Values Scale (WVS), validated in Brazil by Porto and Tamayo (2003), and the Inventory of Work Motivation and Meaning (IWMM), validated in Brazil by Borges and Alves Filho (2003). For data analysis, resources of descriptive statistics were used. Thus, this study took up the challenge of being a dialectical approach to the phenomenon in focus, based on the conception of work in a prison setting. The results show that to achieve professional stability, earn fair economic rewards and take up responsibilities are aspects of vital importance for the majority of the prison officers. The significance of work is directly associated with personal and family survival and the responsibility that they have both in the work and family contexts. Their motivation is associated with security and dignity. The main work-related aspect valued by prison officers is stability and the less important is prestige. At the end of the process of researching and producing knowledge, it is important to emphasize that important aspects about the prison officers’ work relations emerged, an activity that is intertwined by social stigmas that can affect all their living environments.

Chemical reaction monitoring via the light focusing in optofluidic waveguides

This paper studies the light focusing phenomenon in optofluidic waveguides and uses it to monitor chemical reactions. Firstly, the relationship between the light focusing pattern and its contributing factors is investigated experimentally. Next, a characterization experiment is conducted to validate the use of light focusing pattern as an indicator of diffusion properties. The sensitivity and the limit-of-detection (LOD) are measured to be 1.54 μm/(μm2/s) and 3.93 × 10−12 m2/s in the over-mixed region, respectively. Then, the sucrose hydrolysis reaction is monitored using the proposed optofluidic method as a demonstration. The initial hydrolysis rate of this reaction is measured to be 19.62 μM/min, which agrees reasonably well with the reported value. Lastly, this method is extended to determine the diffusion coefficient of binary solutions. The diffusion coefficients of ethylene glycol and glycerol in water are measured to be 5.56 ± 0.12 × 10-10 and 7.01 ± 0.20 × 10-10 m2/s, respectively. This study demonstrates a new method for potential integrated biochemical sensing and paves the way for a broad range of sensing applications in microreactors, chemical synthesis, and quantification of biomolecular interactions.

Universal pathogenicity of authoritarian focus in pedagogues’ professional communications

&#x0D; The paper examines the specificity of authoritarian focus in pedagogues’ professional communications, which can be the source of psychological traumatisation, provoke the development of health deviations among the participants of education process, causing the emergence of functional and chronicle diseases. It is observed, that the authoritarian focus under the conditions of stressful professional reality creates “chronicle” psycho-traumatic atmosphere in professional communications of employee and can provoke emergence of negative emotional experiences (psychogeneses). Important aspect of examined problem is the fact, that authoritarian interactions in activities (learning, professional) can be the reason for emergence of children's didactic geneses and development of neuroses. Pedagogue’s sensibility to the demonstrations of authoritarianism points out the undeveloped readiness to build effective professional pedagogical communications, which can become the source of traumatisation and aggravation of pedagogue’s own didactopathy. The results of empirical study of influence of factor “authoritarianism” on the pedagogues’ occupational health with the author’s technique “Occupational health” are presented. The observed correlation tendencies indicate the phenomenon of authoritarian focus in pedagogue’s professional communications, that’s why the authoritarianism syndrome can be the serious barrier for the progressive professional development of the specialist, the ruining factor to the professional communications, which influence the psychological well being and health state of employee. Pedagogue with authoritarian focus of world perception is characterized by the behaviour, which is based on the belief, that using of own status and authority provides the sustaining of hierarchical subordination, control, security and professional stability.&#x0D;

Ecological efficiency in China and its influencing factors-a super-efficient SBM metafrontier-Malmquist-Tobit model study.

Ecological problem is one of the core issues that restrain China's economic development at present, and it is urgently needed to be solved properly and effectively. Based on panel data from 30 regions, this paper uses a super efficiency slack-based measure (SBM) model that introduces the undesirable output to calculate the ecological efficiency, and then uses traditional and metafrontier-Malmquist index method to study regional change trends and technology gap ratios (TGRs). Finally, the Tobit regression and principal component analysis methods are used to analysis the main factors affecting eco-efficiency and impact degree. The results show that about 60% of China's provinces have effective eco-efficiency, and the overall ecological efficiency of China is at the superior middling level, but there is a serious imbalance among different provinces and regions. Ecological efficiency has an obvious spatial cluster effect. There are differences among regional TGR values. Most regions show a downward trend and the phenomenon of focusing on economic development at the expense of ecological protection still exists. Expansion of opening to the outside, increases in R&D spending, and improvement of population urbanization rate have positive effects on eco-efficiency. Blind economic expansion, increases of industrial structure, and proportion of energy consumption have negative effects on eco-efficiency.

THz wavefront manipulation based on metal waveguides

In this paper, two waveguiding structures for arbitrary wavefront manipulation in the terahertz spectral region were proposed, designed and characterized. The first structure consists of parallel stack copper plates forming an array of parallel-plate waveguides (PPWGs). The second structure is three-dimensional metal rectangular waveguides array. The phase delay of the input wave after passing through the waveguide array is mainly determined by the effective index of the waveguides. Therefore, the waveguide array can be engineered using different core width distribution to generate any desired light beam. Examples, working at the frequency of 0.3 THz show that good focusing phenomenon with different focus lengths and spot sizes were observed, as well as arbitrarily tilted propagation of incident plane waves. The structure introduces a new method to perform wavefront manipulation, and can be utilized in many important applications in terahertz imaging and communication systems.

Exploring the feasibility of focusing CW light through a scattering medium into closely spaced twin peaks via numerical solutions of Maxwell’s equations

Here we present a numerical simulation to analyze the effect of scattering on focusing light into closely-spaced twin peaks. The pseudospectral time-domain (PSTD) is implemented to model continuous-wave (CW) light propagation through a scattering medium. Simulations show that CW light can propagate through a scattering medium and focus into closely-spaced twin peaks. CW light of various wavelengths focusing into twin peaks with sub-diffraction spacing is simulated. In advance, light propagation through scattering media of various number densities is simulated to decipher the dependence of CW light focusing phenomenon on the scattering medium. The reported simulations demonstrate the feasibility of focusing CW light into twin peaks with sub-diffraction dimensions. More importantly, based upon numerical solutions of Maxwell’s equations, research findings show that the sub-diffraction focusing phenomenon can be achieved with scarce or densely-packed scattering media.

Focusing optical waves with a rotationally symmetric sharp-edge aperture

While there has been various kinds of patterned structures proposed for wave focusing, these patterned structures usually involve complicated lithographic techniques since the element size of the patterned structures should be precisely controlled in microscale or even nanoscale. Here we propose a new and straightforward method for focusing an optical plane wave in free space with a rotationally symmetric sharp-edge aperture. The focusing phenomenon of wave is realized by superposition of a portion of the higher-order symmetric plane waves generated from the sharp edges of the apertures, in contrast to previously focusing techniques which usually depend on a curved phase. We demonstrate both experimentally and theoretically the focusing effect with a series of apertures having different rotational symmetry, and find that the intensity of the hotspots could be controlled by the symmetric strength of the sharp-edge apertures. The presented results would advance the conventional wisdom that light would diffract in all directions and become expanding when it propagates through an aperture. The proposed method is easy to be processed, and might open potential applications in interferometry, image, and superresolution.

Material influence on hot spot distribution in the nanoparticle heterodimer on film

The metal nanoparticle aggregated on film, as an effective plasma enhancement pathway, has been widely used in various surface plasmon-related fields. In this study, the hot spots on the metal nanoparticle dimer composed of different materials (AgAu, AgPd, and Ag Cu) on metal (Au) film were investigated with finite element method. Based on the results, the hot spot distribution affected by the material can be confirmed by the electric field distribution of the metal nanoparticle dimer on the film. The aggregation effects of Au and Ag nanoparticles in Au Ag dimer system are not significant. However, for the PdAg dimer system, the hot spot aggregation effect is slightly larger than that of the Pd nanoparticle under the Ag nanoparticle. Besides, the non-uniform hot spots would bring about the light focusing phenomenon that the light intensity under Ag nanoparticle is almost 100 times greater than that under Cu nanoparticle in AgCu dimer system. These results were further confirmed by the surface charge distribution, and analyzed based on the plasmonic hybridization theory. The data about the nanoparticle dimer on the dielectric (Si) film demonstrate the importance of induced image charges on the film surface in such a light focusing phenomenon. Our findings can enhance the understanding of the surface plasmon coupling in different materials, which may have great application prospects in surface plasmon-related fields, such as SERS, plasmonic enhanced solar cell, and plasmonic sensoring, etc.

Review of the Functions of Archimedes' Spiral Metallic Nanostructures.

Here, we have reviewed some typical plasmonic structures based on Archimedes’ spiral (AS) architectures, which can produce polarization-sensitive focusing phenomenon and generate plasmonic vortices (PVs) carrying controllable orbital angular momentum (OAM) because of the relation between the incident polarized states and the chiralities of the spiral structures. These features can be used to analyze different circular polarization states, which has been one of the rapidly developing researching topics in nanophotonics in recent years. Many investigations demonstrate that the multifunctional spiral-based plasmonic structures are excellent choices for chiral selection and generating the transmitted field with well-defined OAM. The circular polarization extinction ratio, as an evaluation criterion for the polarization selectivity of a designed structure, could be effectively improved by properly modulating the parameters of spiral structures. Such functional spiral plasmonic nanostructures are promising for applications in analyzing circular polarization light, full Stokes vector polarimetric sensors, near-field imaging, and so on.

Modeling the sub-diffraction focusing phenomenon of light propagation through scattering medium.

Optical techniques are assuming greater importance in biomedical applications, however, due to extreme complexity involved in light propagation through scattering medium, it is very challenging to analyze experimentally. Here we report a two-stage simulation technique to simulate phase-conjugated light propagation through scattering medium with macroscopic dimensions. The reported simulation yields accurate information with flexibility to access research parameters. The proposed simulation method is suitable for finite-difference time-domain (FDTD) technique, pseudospectral time-domain (PSTD) technique, and other simulation techniques based upon numerical solutions of Maxwell's equations. We demonstrate modeling phase-conjugated light propagation through a scattering medium. The reported simulation technique is applicable to model the propagation of continuous-wave (CW) light with specific amplitude and phase through a scattering medium of macroscopic dimensions. More importantly, the flexibility of simulation enables analysis of research factors that are challenging to access experimentally.

Focusing ultrasonic waves in a 2-D covered channel above the periodic array of Helmholtz resonators

This paper presents the numerical simulation and experiments on focusing low-frequency ultrasonic waves in a 2-D covered channel above acoustic metamaterials composed of the periodic array of Helmholtz resonators, in which the refractive index can be in a negative value. The 2-D channel above the acoustic metamaterials is covered by a plate to limit the area affected by the negative refractive index metamaterials. Ultrasonic waves propagated in the 2-D covered channel are found to be highly dependent on input frequency and the designed Helmholtz resonator structure, where its negative refractive index causes the focusing phenomenon in this channel. From the numerical simulation and experiments, an amplitude focus spot is observed in the peak-to-peak of the time domain signal and frequency response at 125 kHz by mapping a pressure field in the 2-D covered channel. Different focal points with several input frequencies are also identified. Our research demonstrates the possibility of applying the designed lens based on acoustic metamaterials to improve the focusing effect in ultrasonic testing.

Exchange electrode-electrokinetic remediation of Cr-contaminated soil using solar energy

Abstract The present work focused on analyzing the effects of solar energy on the electrokinetic remediation (EKR) of Cr-contaminated soil, compared to direct current (DC) power supply. Meanwhile, to control the remedied soil pH and focusing phenomena, the exchange electrode-EKR (EE-EKR) has also been employed. Four runs of tests were conducted using DC power supply with the conventional EKR (run A, run D), DC power supply with EE-EKR (run B) and solar energy with EE-EKR (run C) respectively. Important electrokinetic parameters such as electrical voltage and current, electroosmotic flow, soil pH, the remediation efficiency of total Cr, Cr(VI), Cr(III) and cost analysis were investigated to evaluate EE-EKR using solar energy. The results show that run B had the highest removal efficiency of total Cr (43.65%), Cr(VI) (91.88%), and Cr(III) (19.32%), and run C, run A, run D follow in turn. It was proved that EE-EKR could increase the removal efficiency of Cr, especially Cr(III) from contaminated soil, because it could reduce focusing phenomena and enhance electrical current. Meanwhile, the experimental results also indicated that the combination of electrokinetics and solar energy was feasible and effective to some extent for the remediation of Cr-contaminated soil.

A mudança na posição estrutural de foco no português brasileiro

O presente capítulo é uma revisita aos estudos diacrônicos de Kato e de Kato e colaboradores sobre o PB no que diz respeito às estruturas de Foco, mostrando que antes do século XVIII o português fazia uso da projeção alta do FocusP, na periferia da sentença, e que a grande mudança estrutural relativamente a Foco tem a ver com a desativação desse Focus alto e a ativação da periferia baixa adjacente ao vP, tanto para foco como também para os constituintes-wh. Mudanças mais recentes são analisadas como processos em PF. Consideramos neste trabalho uma alternativa à cartografa, com um CP sem expansão e sem a consideração do FocusP na periferia do vP, mas à primeira vista, o modelo cartográfco parece dar conta melhor do fenômeno do Foco no Português Brasileiro.

Global spectral analysis of three-time level integration schemes: Focusing phenomenon

Here, we explain the phenomenon of focusing using the numerical properties of space–time discretization methods involving second-order Adams–Bashforth (AB2) method for the solution of one–dimensional (1D) convection equation. It has been established that solving 1D convection equation by three–time level method invokes a numerical or spurious mode, apart from the physical mode (as explained in Sengupta et al., [27]). Here, the long elusive problem of focusing (considered as a problem of non-linear numerical aspect), is shown due to a linear mechanism. The focusing is shown for a wave–packet propagating in a non-periodic domain by a three–time level method. Long time integration shows the physical mode to cause focusing, which shows up as spectacular growth of error–packet(s) at discrete location(s), where the dominant wavenumber (k) depends only on the CFL number (Nc), for the space–time discretization method. The length scale of growing error is independent of wavenumber of the input signal. It is also established that focusing is related to numerical absolute instability, for which the numerical group velocity (VgN1) of the physical mode is zero. However, interestingly, when a compact filter is used, the focusing phenomenon is converted from absolute to convective numerical instability. This brings new insight and satisfactory explanation of focusing and its dependence on the choice of numerical methods and use of filter. As a demonstration of the focusing phenomenon for AB2 method, we use it with a well known combined compact differencing scheme to solve Navier–Stokes equation in a square lid driven cavity for a super-critical post–Hopf bifurcation Reynolds number of 10,000 (based on the side of the cavity and the constant lid velocity). Contrary to the well-established solution with polygonal vortices in the literature, here the solution breaks down after a finite time due to focusing.