The present paper investigates the impact of three radiation patterns of LED namely Lambertian, Batwing, Elliptical on the BER performance of 4 × 4 indoor multiple-input multiple-output (MIMO) visible light communication (VLC) system. The BER simulation has been done using LOS and LOS plus first reflection (L-R1) signals for ceiling-mounted and wall-mounted LEDs. For the case of ceiling-mounted LEDs, impulse response and BER have been computed using those radiation patterns at the centre and corner of a room (5 m × 5 m × 3 m). It has been found that LED having Elliptical radiation profile is more suitable for LOS signal when receiver is placed at the centre position whereas, Batwing radiation is suitable for L-R1 signal, both at the centre and corner positions. In the case of wall-mounted LEDs, impulse response and BER have been determined at the centre of the room using LOS and L-R1 signals. The results show that Batwing has least BER using LOS signal due to its wide radiation beam, but for L-R1 signal, the Elliptical profile having its narrow radiation beam has provided better BER performance. The present study shows that the BER in MIMO-VLC system not only depends on the transmitter and receiver position but also on the radiation patterns of LED and higher order reflection signals.
Climate change causes environmental depletion, with threats to the global economy. The health and productivity of ecosystems underpin agriculture, with stable ecosystems being the foundation for economic livelihoods and food security. This study proposes adaptation measures, using geospatial technology, for conserving natural resources and improving livelihoods of the local community from climate change scenarios. Planning, policy decisions and resultant programmes are required for natural resource management, which must be based on broad citizen participation and the engagement of rural communities. The suggested adaptation measures will help the planning system to regulate development of natural resources and the socio‐economic environment. The major natural resources in the environment are land and water, both of which can be severely degraded by human interventions, as well as climate change. Various thematic maps are prepared with the use of geospatial technology, in order to be helpful for site‐suitability analysis directed to the preparation of land and water management action plans for socio‐economic development. The study area is a micro‐watershed of the catchment of Ansupa Lake in the Cuttack District of Odisha, India. To reduce climate change impacts on natural resources and economic livelihoods, some adaptation measures have been proposed (e.g., 68.9 ha for afforestation.; 13.94 ha for gap plantations and agro‐horticulture; 389.62 ha for farm ponds and renovation of existing ponds for pisciculture and duckery activities, etc.; 11.33 ha for land management, along with five bore wells, eight dug wells, 51 LBS/check dams, and four WHSs, etc., for water management for sustainable use). 相似文献
Sustainable and cost‐effective energy generation has become crucial for fulfilling present energy requirements. For this purpose, the development of cheap, scalable, efficient, and reliable catalysts is essential. Carbon‐based heteroatom‐doped, 3D, and mesoporous electrodes are very promising as catalysts for electrochemical energy conversion and storage. Various carbon allotropes doped with a variety of heteroatoms can be utilized for cost‐effective mass production of electrode materials. 3D porous carbon electrodes provide multiple advantages, such as large surface area, maximized exposure to active sites, 3D conductive pathways for efficient electron transport, and porous channels to facilitate electrolyte diffusion. However, it is challenging to synthesize and functionalize isotropic 3D carbon structures. Here, various synthesis processes of 3D porous carbon materials are summarized to understand how their physical and chemical properties together with heteroatom doping dictate the electrochemical catalytic performance. Prospects of attractive 3D carbon structural materials for energy conversion and efficient integrated energy systems are also discussed. 相似文献
This article presents a novel framework for the multi-objective optimization of offshore renewable energy mooring systems using a random forest based surrogate model coupled to a genetic algorithm. This framework is demonstrated for the optimization of the mooring system for a floating offshore wind turbine highlighting how this approach can aid in the strategic design decision making for real-world problems faced by the offshore renewable energy sector. This framework utilizes validated numerical models of the mooring system to train a surrogate model, which leads to a computationally efficient optimization routine, allowing the search space to be more thoroughly searched. Minimizing both the cost and cumulative fatigue damage of the mooring system, this framework presents a range of optimal solutions characterizing how design changes impact the trade-off between these two competing objectives. 相似文献
Functional van der Waals heterojunctions of transition metal dichalcogenides are emerging as a potential candidate for the basis of next‐generation logic devices and optoelectronics. However, the complexity of synthesis processes so far has delayed the successful integration of the heterostructure device array within a large scale, which is necessary for practical applications. Here, a direct synthesis method is introduced to fabricate an array of self‐assembled WSe2/MoS2 heterostructures through facile solution‐based directional precipitation. By manipulating the internal convection flow (i.e., Marangoni flow) of the solution, the WSe2 wires are selectively stacked over the MoS2 wires at a specific angle, which enables the formation of parallel‐ and cross‐aligned heterostructures. The realized WSe2/MoS2‐based p–n heterojunction shows not only high rectification (ideality factor: 1.18) but also promising optoelectrical properties with a high responsivity of 5.39 A W?1 and response speed of 16 µs. As a feasible application, a WSe2/MoS2‐based photodiode array (10 × 10) is demonstrated, which proves that the photosensing system can detect the position and intensity of an external light source. The solution‐based growth of hierarchical structures with various alignments could offer a method for the further development of large‐area electronic and optoelectronic applications. 相似文献
To explore the potential of aporphine alkaloids, a novel series of functionalized aporphine analogues with alkoxy (OCH3, OC2H5, OC3H7) functional groups at C1/C2 of ring A and an acyl (COCH3 and COPh) or phenylsulfonyl (SO2Ph and SO2C6H4‐3‐CH3) functionality at the N6 position of ring B of the aporphine scaffold were synthesized and evaluated for their arachidonic acid (AA)‐induced antiplatelet aggregation inhibitory activity and 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) free‐radical‐scavenging antioxidant activity, with acetylsalicylic acid and ascorbic acid as standard references, respectively. The preliminary structure–activity relationship related to AA‐induced platelet aggregation inhibitory activity results showed that the aporphine analogues 1‐[1,2,9,10‐tetramethoxy‐6a,7‐dihydro‐4H‐dibenzo[de,g]quinolin‐6(5H)‐yl]ethanone and 1‐[2‐(benzyloxy)‐1,9,10‐trimethoxy‐6a,7‐dihydro‐4H‐dibenzo[de,g]quinolin‐6(5H)‐yl]ethanone to be the best compounds of the series. Moreover, the DPPH free‐radical‐scavenging antioxidant activity results demonstrated that the aporphine analogues 1,2,9,10‐tetramethoxy‐6‐(methylsulfonyl)‐5,6,6a,7‐tetrahydro‐4H‐dibenzo[de,g]quinoline, 2‐ethoxy‐1,9,10‐trimethoxy‐6‐(methylsulfonyl)‐5,6,6a,7‐tetrahydro‐4H‐dibenzo[de,g]quinoline, 1‐ethoxy‐2,9,10‐trimethoxy‐6‐(methylsulfonyl)‐5,6,6a,7‐tetrahydro‐4H‐dibenzo[de,g]quinoline, 2,9,10‐trimethoxy‐6‐(methylsulfonyl)‐1‐propoxy‐5,6,6a,7‐tetrahydro‐4H‐dibenzo[de,g]quinoline, and 1‐(benzyloxy)‐2,9,10‐trimethoxy‐6‐(methylsulfonyl)‐5,6,6a,7‐tetrahydro‐4H‐dibenzo[de,g]quinoline were the best compounds of the series. Moreover, in silico molecular docking simulation studies of the active analogues were also performed. 相似文献
Electronic transport through ruthenium-based redox-active organometallic molecules is measured by self-assembling diruthenium(III) tetra(2-anilinopyridinate)-di(4-thiolphenylethynyl) (trans-Ru2(ap)4(C'CC6H4S-)2 (A) and trans- Ru2(ap)4((C'CC6H4)2S-)2 (B) molecules in nanogap molecular junctions. Voltage sweeps at a high scan rate show low bias current peaks (at +/-0.35 +/- 0.05 V for A and +/-0.27 +/- 0.05 V for B), which change to plateaus in slow bias scans and a second conductance peak at approximately +/-1.05 +/- 0.15 V. The peaks/plateaus are not observed in the return bias sweeps, possibly due to charge storage in the molecules. The energy states for the molecular orbitals of these molecules as estimated from the conductance peaks are in close agreement with the respective energy values from voltammetric measurements in solution. 相似文献