Fluctuations of VHF field in the vicinity of the maximum frequency of operation (shadow-zone boundary)

Liquid crystal (LC) cells that are coated with metamaterials are fabricated in this work. The LC directors in the cells are aligned by rubbed polyimide layers, and make angles θ of 0°, 45°, and 90° with respect to the gaps of the split-ring resonators (SRRs) of the metamaterials. Experimental results display that the resonance frequencies of the metamaterials in these cells increase with an increase in θ, and the cells have a maximum frequency shifting region of 18 GHz. Simulated results reveal that the increase in the resonance frequencies arises from the birefringence of the LC, and the LC has a birefringence of 0.15 in the terahertz region. The resonance frequencies of the metamaterials are shifted by the rubbing directions of the polyimide layers, so the LC cells coated with the metamaterials are passively tunable terahertz filters. The passively tunable terahertz filters exhibit promising applications on terahertz communication, terahertz sensing, and terahertz imaging.

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Development of stable transgenic maize plants tolerant for drought by manipulating ABA signaling through Agrobacterium-mediated transformation

Journal of Genetic Engineering and Biotechnology ◽

10.1186/s43141-021-00195-2 ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Sridevi Muppala ◽

Pavan Kumar Gudlavalleti ◽

Kodandarami Reddy Malireddy ◽

Sateesh Kumar Puligundla ◽

Premalatha Dasari

Keyword(s):

Abiotic Stress ◽

Inbred Line ◽

Biochemical Characterization ◽

Abiotic Stress Tolerance ◽

Crop Improvement ◽

Maximum Frequency ◽

Aba Signaling ◽

Tolerant Plants ◽

Maize Plants ◽

Gateway Technology

Abstract Background In crop plants, to cope up with the demand of food for rising population, revolutionary crop improvement programmes are being implemented for higher and higher yields. Abiotic stress, especially at flowering stage, causes drastic effect on yield in plants. Deforestation and urbanization made the water table very low and changed the climate which led to untimely and unforeseen rains which affect the yield of a crop through stress, both by lack of water as well as water logging (abiotic stress). Development of tolerant plants through breeding is a time-consuming programme and does not perform well in normal conditions. Development of stress-tolerant plants through transgenic technology is the better solution. Maize is a major crop used as food and fodder and has the commercial value in ethanol production. Hence, the genes viz., nced (9-cis-epoxycarotenoid dioxygenase) and rpk (receptor-like protein kinase), which play the key roles in the abscisic acid pathway and upstream component in ABA signaling have been transferred into maize plants through Agrobacterium-mediated transformation by optimizing several parameters to obtain maximum frequency of transformation. Results Cultures raised from immature embryos of 2-mm size isolated from maize cobs, 12–15 days after pollination, were used for transformation. rpk and nced genes under the control of leaP and salT promoters respectively, cloned using gateway technology, have been introduced into elite maize inbred lines. Maximum frequency of transformation was observed with the callus infected after 20 days of inoculation by using 100 μM acetosyringone, 10 min infection time, and 2 days incubation period after co-cultivation resulted in maximum frequency of transformation (6%) in the NM5884 inbred line. Integration of the genes has been confirmed with molecular characterization by performing PCRs with marker as well as gene-specific primers and through southern hybridization. Physiological and biochemical characterization was done in vitro (artificial stress) and in vivo (pot experiments). Conclusions Changes in the parameters which affect the transformation frequency yielded maximum frequency of transformation with 20-day-old callus in the NM5884 inbred line. Introducing two or more genes using gateway technology is useful for developing stable transgenic plants with desired characters, abiotic stress tolerance in this study.

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Design and Implementation of Maiden Dual-Level Controller for Ameliorating Frequency Control in a Hybrid Microgrid

Energies ◽

10.3390/en14092418 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2418

Author(s):

Abdul Latif ◽

S. M. Suhail Hussain ◽

Dulal Chandra Das ◽

Taha Selim Ustun

Keyword(s):

Frequency Control ◽

Electric Heater ◽

Maximum Frequency ◽

Stabilization Time ◽

Control Approach ◽

Proportional Integral ◽

Hybrid Microgrid ◽

Performance Results ◽

System Frequency ◽

Test Scenarios

It is known that keeping the power balance between generation and demand is crucial in containing the system frequency within acceptable limits. This is especially important for renewable based distributed hybrid microgrid (DHμG) systems where deviations are more likely to occur. In order to address these issues, this article develops a prominent dual-level “proportional-integral-one plus double derivative {PI−(1 + DD)} controller” as a new controller for frequency control (FC) of DHμG system. The proposed control approach has been tested in DHμG system that consists of wind, tide and biodiesel generators as well as hybrid plug-in electric vehicle and an electric heater. The performance of the modified controller is tested by comparing it with standard proportional-integral (PI) and classical PID (CPID) controllers considering two test scenarios. Further, a recently developed mine blast technique (MBA) is utilized to optimize the parameters of the newly designed {PI − (1 + DD)} controller. The controller’s performance results are compared with cases where particle swarm optimization (PSO) and firefly (FF) techniques are used as benchmarks. The superiority of the MBA-{PI − (1 + DD)} controller in comparison to other two strategies is illustrated by comparing performance parameters such as maximum frequency overshoot, maximum frequency undershoot and stabilization time. The displayed comparative objective function (J) and JFOD index also shows the supremacy of the proposed controller. With this MBA optimized {PI − (1 + DD)} controller, frequency deviations can be kept within acceptable limits even with high renewable energy penetration.

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Novel idiotypic and antigen-binding characteristics in two anti-dinitrophenyl monoclonal antibodies.

Journal of Experimental Medicine ◽

10.1084/jem.146.1.282 ◽

1977 ◽

Vol 146 (1) ◽

pp. 282-286 ◽

Cited By ~ 6

Author(s):

N H Sigal

Keyword(s):

Monoclonal Antibodies ◽

Germ Line ◽

Hypervariable Region ◽

Weight Basis ◽

Antigen Binding ◽

The Novel ◽

Maximum Frequency ◽

Somatic Variant ◽

Binding Characteristics ◽

Cell Pool

Monoclonal anti-dinitrophenyl antibodies generated in the splenic focus system from B cells of adult BALB/c mice were studied for the presence or absence of murine anti-T15 (M anti-T15) reactivity and for their ability to bind phosphorylcholine (PC). Two foci of the 680 clones analyzed bound PC, and one of these antibodies reacted with M anti-T15 and anti-Fab on a 1:1 weight basis. The discovery of a clonotype reactive with M anti-15 but not with rabbit anti-T15 (R anti-T15) serum, the converse of the R anti-T15+, M anti-T15- clonotype identified in the PC-specific repertoire, points to the novel idiotypic relationships which may be found among homogeneous antibodies binding diverse antigens. The R anti-T15-, M anti-T15+ clonotype may represent a distinct set of hypervariable region sequences inserted into the T15 framework or may be a somatic variant of the T15 germ-line sequence. In addition, the maximum frequency with which this clonotype occurs within the B-cell pool is estimated.

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