Double Splitting Research Articles

Detection of Water Quality using Defected Ground Double Split Ring Resonator

Water is an essential thing for life. Now days due to population growth and pollution, the quality of water is degraded. In this paper, a single element double split ring resonator (DSRR) has been presented as a sensor to detect the quality of water. Here, two square shape metallic split rings are designed along with the microstrip line. On the back side of the substrate, defected ground structure (DGS) is introduced. The resonant frequency of the resonator is 11.12 GHz. Quality of water is detected by the shift in S21 resonant frequency with the variation in transmission coefficient. This sensor can be used in our daily life to detect the quality of water and it may be useful in medical field also.

U-joint Double split O (UDO) shaped with split square metasurface absorber for X and ku band application

This paper reports, a metasurface absorber which is U-joint loaded Double Split O shaped with a square split patch at the center and Double Negative (DNG) property. The proposed absorber shows significant absorption for potential applications like radar signal absorption and satellite communication, remote sensing, RF shielding. The vertical U joint and split O mutually creates substantial resonance and expedite by the center square patch, to cover two consecutive X and Ku band absorption peaks at 11.56 GHz with 82.31%, 12.27 GHz with 98.91% and 14.19 GHz with 97.79%. Besides, balanced geometrical shape with insensitivity polarization for TE and TM mode wave propagation enhances the robustness and tunability of the structure. The absorption mechanism analyzed and discussed with the Finite Integration Technique (FIT). Characterization of S-parameter executed with an established method for dielectric property extraction and finally compared the proposed absorber with existing literature.

Bandwidth enhancement of five-port reflectometer-based ENG DSRR metamaterial for microwave imaging application

A five-Port Reflectometer (FPR) with the integration of ultra-wideband (UWB) Epsilon Negative (ENG) Double Split Ring Resonator (DSRR) metamaterial array is introduced in this paper for microwave imaging (MWI) application. The designed DSRR consists of two concentric rings with a split in each which are spatially rotated by 180°, formed an inverted structure to exhibit a wide negative epsilon bandwidth of 187 % (from 0.5 GHz to 15 GHz). The FPR is designed using a ring junction topology and semi-circularly curved inter-port transmission lines (TLs) which are placed between five equally spaced ports. Localizing the DSRR metamaterial in a periodic array of 5 × 4 at the ground plane of FPR lead to 79.79 % fractional bandwidth and reflection coefficient within the operating frequencies of 0.991 GHz–2.2576 GHz. Equivalent circuit model has been alluded with an intricate description of different array configurations of the metamaterial unit cell. Comparison of EM simulation and circuit simulation has been performed to validate the equivalent circuit model. It is found that the existence of stray capacitance, Cstray which is represented by the DSRR configurations, significantly influenced the resonant frequency and bandwidth of FPR. Measured results of the proposed design suits well with the simulations and prove higher efficacious applicability of the proposed design for microwave imaging application. A comparison of the reconstructed image also proves its suitability for the microwave imaging application.

A Smooth Double Proximal Primal-Dual Algorithm for a Class of Distributed Nonsmooth Optimization Problems

This technical note studies a class of distributed nonsmooth convex consensus optimization problems. The cost function is a summation of local cost functions which are convex but nonsmooth. Each of the local cost functions consists of a twice differentiable (smooth) convex function and two lower semi-continuous (nonsmooth) convex functions. We call these problems as single-smooth plus double-nonsmooth (SSDN) problems. Under mild conditions, we propose a distributed double proximal primal-dual optimization algorithm. Double proximal splitting is designed to deal with the difficulty caused by the unproximable property of the summation of those two nonsmooth functions. Besides, it can also guarantee that the proposed algorithm is locally Lipschitz continuous. An auxiliary variable in the double proximal splitting is introduced to estimate the subgradient of the second nonsmooth function. Theoretically, we conduct the convergence analysis by employing Lyapunov stability theory. It shows that the proposed algorithm can make the states achieve consensus at the optimal point. In the end, nontrivial simulations are presented and the results demonstrate the effectiveness of the proposed algorithm.

The modulus-based matrix double splitting iteration method for linear complementarity problems

For large sparse linear complementarity problems, through reformulating them as implicit fixed-point equations, we propose a modulus-based matrix double splitting (MB-DS) iteration method by splitting the system matrices twice. Besides, the convergence of this method is proved when the system matrix is a P-matrix and an H+-matrix. In some special cases, we present the convergence regions and the optimal values for the parameter ω. In order to show the efficiency of the MB-DS iteration method and the effectiveness of the optimal parameter, some corresponding numerical experiments are performed.

An Acoustic Hyperlens with Negative Direction Based on Double Split Hollow Sphere

This study develops a new acoustic negative-refraction metamaterial that utilizes a synthesized double split hollow sphere (DSHS) for its unit cell. Recent relevant research has affirmed the concept that acoustic metamaterials can show unusual behavior that has not been observed in nature previously. However, as some hypothetical metamaterial designs have material properties not found in nature, the realization of practical metamaterials requires practical and complicated models. As a contribution to the development of acoustic metamaterials, the present study proposes a new anisotropic unit structure that encompasses Helmholtz resonators. This structure is referred to as the DSHS, is easy to manufacture, and has the advantage in that it uses the natural medium in its original form. By drawing the equifrequency or isofrequency contours of the designed two-dimensional (2D) anisotropic unit structure using the Floquet–Bloch’s principle, the properties of the present metamaterial can be understood. Numerical simulations are also conducted to identify and present the characteristics of the presented acoustic metamaterial. Through these, a new refraction phenomenon is identified that deviates from Snell’s law, and an acoustic hyperlens is numerically implemented that overcomes the diffraction limit.

Gain and Bandwidth Enhancement of Microstrip Antenna Array using Double Square Split Ring Resonator FSS as a Superstrate for WiMax/WiFi/WLAN Applications

Gain and Bandwidth Enhancement of Microstrip Antenna Array using Double Square Split Ring Resonator FSS as a Superstrate for WiMax/WiFi/WLAN Applications

Evaluation of Shear Bond Strength of Self-Adhering Flowable Composite to Mineral Trioxide Aggregate and Biodentine

This study aimed to evaluate shear bond strength of mineral trioxide aggregate and biodentine to self-adhering flowable composite. Materials and Methods: eighty Double Split Teflon mold has been prepared with a central hole measuring (3mm in diameter and 2 mm in height) for the mold used for tested materials and (2mm in diameter and in height) for the other mold used for restorative material. The molds were filled with MTA and Biodentine. The mixing material MTA and biodentine applied to its mold (n = 40) and allocated into 2 groups. The specimens will store for72 hours at 37˚C and 100% humidity. After 72 hours, self-adhering flowable composite was applied over MTA and Biodentine with a height and diameter each of 2 mm. The samples were stored in Incubator for 24 hours at 37˚C to enhance setting and then removed from the mold. SBS was measured in a universal testing machine with a load cell of 5kN and a crosshead speed of 0.5 mm/min. Data were analyzed using Graph Pad Instat. A value of P .05).Conclusion Biodentine exhibited higher SBS than MTA; therefore, they could be preferred under flowable composites

Number of components and prediction error in partial least squares regression determined by Monte Carlo resampling strategies

Using a metabolomics data set with 1057 serum samples, we designed and assessed different procedures based on Monte Carlo resampling schemes to determine the optimal number of components to be included in partial least squares (PLS) regression models. Corresponding estimates of prediction error were calculated and compared in a single algorithm comprising i) a single loop Monte Carlo approach repeatedly and randomly splitting samples into calibration and validation samples, ii) a double loop validation splitting samples into calibration/validation and prediction sets, and, iii) independent sample sets in a third loop. In order to mimic the common situation with only a moderate number of samples available for building the model, only a fraction of the 1057 samples analyzed was randomly selected from the total sample set and used in the algorithm. The results show that if the samples available for modelling are representative for the future samples to be predicted from the model, the single loop Monte Carlo procedure consistently provides the same estimates of prediction errors as double loop resampling procedures and for 75% of the cases these estimates are the same as for independent prediction sets. This has important implications for optimal use of a training set for component selection and estimation of prediction error. Two methods were developed and compared for selecting the optimal number of PLS components defined as the number where no statistically significant improvement in prediction error is observed when additional components are included in the model. Both methods determine a probability measure and provide similar results for model selection in this application.

The terahertz electromagnetically induced transparency-like metamaterials for sensitive biosensors in the detection of cancer cells

A kind of novel biosensor based on the electromagnetic induced transparency like (EIT-like) metamaterials (MMs) have been proposed. It demonstrates that the symmetry-breaking double-splits ring resonators can realize the EIT-like plasmonic resonance, the according transparency window occurs at 1.67 THz. The coupled oscillators model illustrates that with the increase of asymmetry degree of double splits, the coupling between bright and dark mode is enhanced. Consequently, the non-radiative damping γ2 grows from 1.45 to 1.85 THz and coupling coefficient κ from 3.46 to 4.49 THz2, while the radiative damping γ1 decreases from 11.5 to 9 THz. Such EIT-like MMs were evaluated in simulation as the refractive index sensors, which the theoretical sensitivity was calculated to 455.7 GHz/RIU (RIU, Refractive Index Unit) under 11 μm-thick analyte layer. Meanwhile, the dependence of full width at half maximum (FWHM) on analyte thickness was also studied. In experiments, it is found that the frequency shift Δf increases from 50 to 90 GHz when the oral cancer cells (HSC3) concentration improves from 1 × 105 to 7 × 105 cells/ml. The maximum experimental sensitivity approaches 900 kHz/cell ml−1 at 7 × 105 cells/ml. Additionally, the apoptosis of cancer cells under the effect of anti-cancer drug was investigated. It shows that with the increase of anti-cancer drug concentration from 1 to 15 μM and the extension of drug action duration from 24 to 72 h, the Δf changes from 140 to 70 GHz and 140–40 GHz, respectively. Besides, the corresponding FWHM also increases from 237.9 to 305.4 GHz and 237.8–337.6 GHz. The results measured by MMs biosensors and biological method exhibit a relatively good agreement, showing a great potential for cells measurement with the sensitive biosensors based on the EIT-like MMs.

An effective stationary iterative method via double splittings of matrices

In this paper, a new stationary iterative method based on two double splittings of coefficient matrix is proposed to solve linear system Ax=b. Some convergence results and comparison theorems of the new method are provided. Theoretical analysis shows that this method is superior to some existing ones under certain conditions. Numerical examples are given to illustrate the theoretical results and examine the effectiveness of the proposed method.

Fourier transform emission spectroscopy and ab initio calculations on the visible spectrum of AlD[formula omitted

The spectrum of the AlD+ isotopologue has been investigated at high resolution in the 27,000−29,000 cm−1 region using a Fourier transform emission spectroscopy technique. The AlD+ molecules were produced within a water-cooled aluminum hollow-cathode lamp in the presence of 1.5 Torr of Ne and 0.8 Torr of ND3. The (0, 0) and (1, 1) bands belonging to the A2Π−X2Σ+system were recorded with an instrumental resolution of 0.03 cm−1. In total, almost 500 rotational frequencies were measured with an absolute accuracy of about 0.005 cm−1. It improved the experimental accuracy of the determined frequencies by the factor 10 compared to the previous work [J Phys B: Mol Phys 1984;17:L861-L866]. The rotational analysis has shown irregularities in the Λ− doubling splitting of the A2Π v=0,1. Consequently, the A2Π state has been represented by the rotational term values, while the regular X2Σ+ state by the molecular constants. The causes of the irregularities were identified in the interaction between the A2Π and the B2Σ+ states, which lies about 3720 cm−1 above. Supporting ab initio quantum chemical calculations, including spin-orbit effects, reproduce the observed spectroscopic constants including the small energy splittings due to spin-rotation interactions (for 2Σ+ states) and Λ−doubling.

Dual‐mode bandpass filter based on substrate‐integrated waveguide loaded with complementary split ring resonators

AbstractA compact dual‐mode bandpass filter adapted from circular substrate‐integrated waveguide (SIW) is presented in this paper. The excited modes of the cavity are controlled by introducing metal vias and loading complementary split ring resonators (CSRRs) to the cavity. Higher order dual resonant modes are used to generate the passband response. Single ring CSRRs with double splits are loaded in the SIW cavity to provide independent control over the passband resonant modes. The loading of CSRRs contributes to further size reduction of the cavity. The fundamental mode of the cavity is controlled by using optimally configured metal vias. Thus, a nearly symmetric passband response and an improved out‐of‐band response below the dual‐mode passband are achieved by suppressing the fundamental mode. The modified SIW cavity loaded with CSRRs reduces the size of the standard circular cavity by 83%. The proposed bandpass filter has center frequency at 8.7 GHz with 14% fractional bandwidth. 0.7 dB is the measured minimum insertion loss with a return loss better than 20 dB.

Response of guinea grass (Megathyrsus maximus) genotypes to intercropping with forage legumes under varying nitrogen management options

AbstractGuinea grass (Megathyrsus maximus) is an important source of forage in India but it remains dormant during the winter season. The space between rows of grass can be utilized by incorporating forage legumes. This 3‐year study evaluated two genotypes of guinea grass in monocropping and intercropping with cowpea and Egyptian clover under different N management options. Guinea grass genotype BG‐2 produced higher dry‐matter yields than BG‐1, both in monocropping and in intercropping. However, dry‐matter yield of forage legumes was higher under BG‐1. The yield advantage in terms of land equivalent ratio was higher in BG‐1 (1.69) than BG‐2 (1.60). BG‐1 was more dominant than BG‐2 in intercropping. Soil properties such as dehydrogenase activity, microbial biomass carbon and available N were improved under grass–legume intercropping compared with grass alone. Higher crude protein and N uptake were also observed in BG‐2. Net returns of grass–legumes intercropping were 30%–40% higher compared with monocropping of guinea grass. Among N management options, higher growth, crude protein content and forage yield were achieved with application of 40 kg N/ha after each cut of guinea grass in double split. Therefore, guinea grass + cowpea–Egyptian clover intercropping with 40 kg N/ha after each grass cut in double split can be suggested for higher forage productivity, profitability and soil properties.

Design of Miniaturized Multiband Patch Antenna Using CSRR for WLAN/WiMAX Applications

A novel miniaturized multiband, single-feed microstrip patch antenna is presented in this paper for WLAN and WiMAX applications. Both size reduction and multiband are obtained by etching the Multiple Complementary Split Ring Resonators (MC-SRR) on the ground plane of the normal patch antenna. At first, the normal patch antenna produces a single band of 5.15 GHz; 200 MHz (5.0500~5.2499). Subsequently, a Single Circular Split Ring Resonator (SC-SRR) is etched on the ground plane and produces a triple band of: 3.25 GHz; 288 MHz (3.1085~3.3964), 4.5 GHz; 101.3 MHz (4.4488~4.5501), and 5.22 GHz; 220 MHz (5.1191~5.3400) and Double Single Circular Split Ring Resonator (DC-MCSRR) with: 2.99 GHz; 60.7 MHz (2.9574~3.0181), 3.57 GHz; 324.7 MHz (3.4065~3.7312), and 5.1413 GHz; 115.4 MHz (5.0817~5.1971). The working bandwidths cover the desired frequency bands of WLAN 5.2 GHz and WiMAX 3.3/3.5 GHz. The proposed (MC-SRR) antenna can be employed to wireless communication systems due to its simplicity in design, compactness and miniaturization.

Breaking the symmetry to manipulate the magnetic Fano resonance in double split ring/square ring structure

Optical properties of the Double Split Ring/Square Ring nanostructurre are investigated by using finite element method. Electric and magnetic resonances at optical frequency can be induced by this nanostructure. The symmetry of the structure is broken by adjusting the arm length of the double split ring and the offsets of the square ring, which leads the changing of inductance and capacitance. New magnetic resonances can be achieved and enhanced. Fano resonances are produced by the overlapping interference between bright electric mode and dark magnetic mode. The nanostructure allows the generation of multiple magnetic Fano resonances and strong magnetic field enhancement, which has potential applications in plasmons propagation with low-loss magnetic and multi-wavelength surface enhanced spectroscopy.

Delay time dependence of wave packet motion and population transfer of four-level K2 molecule in pump–pump–probe pulses**Project supported by the National Natural Science Foundation of China (Grant Nos. 11704178 and 11764041) and the Scientific Research Fund of Hunan Provincial Education Department, China (Grant No. 15B204).

The effect of delay time on photoelectron spectra and state populations of a four-level ladder K2 molecule is investigated by a pump1–pump2–probe pulse via the time-dependent wave packet approach. The periodical motion of the wave packet leads to the periodical change of the photoelectron spectra. The Autler–Townes triple splitting appears at zero delay time, double splitting appears at nonzero delay time between pump1 and pump2 pulses, and no splitting appears at nonzero delay time between pump2 and probe pulses. The periodical change of the state populations with the delay time may be due to the coupling effect between the two pulses. It is found that the selectivity of the state populations may be attained by regulating the delay time. The results can provide an important basis for realizing the optical control of molecules experimentally.

On the Robustness of Earthquake-Resistant Moment-Resistant Frames: Influence of Innovative Beam-to-Column Joints

Background: The deformation capacity of beam-to-column connections strongly influences the robustness of earthquake-resistant Moment Resistant Frames (MRFs) when subjected to a loss-of column scenario. As a consequence, with the aim of foresee the structural response up to the failure, an accurate modelling of the ultimate behaviour of the joints is needed. Objective: In this paper, the influence of the connections on the behaviour of MRFs under a loss-of-column scenario has been analysed considering an accurate modelling of the joints. Method: In addition, in order to achieve this goal, different beam-to-column joints designed for seismic actions and tested at the Salerno University, have been modelled and introduced in a case-study structure, whose response has been evaluated by means of push-down analyses. In particular, the connections analysed and modelled are of three different types: a dog-bone connection, a partial strength Double Split Tee (DST) joint and a partial strength connection with friction dampers. Results / Conclusion: The results of pushdown analyses performed by means of SAP2000 computer software have been examined with the aim to determine the Residual Reserve Strength Ratio (RRSR) index that, combined with the energy balance method proposed by Izzudin et al. (2008), allow to assess the structural ro-bustness.

Design of High Gain, Bandwidth and Efficient Double Split Ring Slotted Antenna with Swastika Shape EBG Structures at 21.29GHz for High Data Rate Communications

Design of High Gain, Bandwidth and Efficient Double Split Ring Slotted Antenna with Swastika Shape EBG Structures at 21.29GHz for High Data Rate Communications

Comparison results for proper double splittings of rectangular matrices

In this article, we consider two proper double splittings satisfying certain conditions, of a semi-monotone rectangular matrix A and derive new comparison results for the spectral radii of the corresponding iteration matrices. These comparison results are useful to analyse the rate of convergence of the iterative methods (formulated from the double splittings) for solving rectangular linear system Ax = b.