Simultaneous wireless information and power transfer for relay assisted energy harvesting network

The simultaneous wireless information and power transfer in an energy harvesting system is investigated, where a relay is self-sustained by harvesting radio-frequency (RF) energy from the transmitter and multiple user devices are distributed according to a homogeneous Poisson point process. A joint time switching and power splitting protocol for relay-assisted transmission is proposed, in which each time slot is split into two stages. In the first stage, the relay utilizes a portion of received RF signal power for energy harvesting and the remaining power for information processing. In the second stage, information is delivered from the relay to its closest destination node with the harvested energy. The outage probability, network throughput and energy efficiency are derived and analyzed in closed form. On this basis, the optimal power splitting and time switching ratio which maximizes network throughput is obtained. Simulation results are also provided to validate our theoretical analysis.     

Towards a Light Weight Routing Security in IoT Using Non-cooperative Game Models and Dempster–Shaffer Theory

Wireless Personal Communications - The internet of things (IoT) has become an emerging technology owing to the rapidly increasing number of devices and their connectivity to the internet. Routing...     

Boosting Infrared Light Harvesting by Molecular Functionalization of Metal Oxide/Polymer Interfaces in Efficient Hybrid Solar Cells

Hybrid solar cells based on light absorbing semiconducting polymers infiltrated in nanocrystalline TiO₂ electrodes, have emerged as an attractive concept, combining benefits of both low material and processing costs with well controlled nano‐scale morphology. However, after over ten years of research effort, power conversion efficiencies remain around 0.5%. Here, a spectroscopic and device based investigation is presented, which leads to a new optimization route where by functionalization of the TiO₂ surface with a molecular electron acceptor promotes photoinduced electron transfer from a low‐band gap polymer(poly[2,6‐(4,4‐bis‐(2‐ethylhexyl)‐4H‐cyclopenta[2,1‐b;3,4‐b0]dithiophene)‐alt‐4,7‐(2,1,3‐benzothiadia‐zole)] (PCPDTBT) to the metal oxide. This boosts the infrared response and the power conversion efficiency to over 1%. As a further step, by “co‐functionalizing” the TiO₂ surface with the electron acceptor and an organic dye‐sensitizer, panchromatic spectral photoresponse is achieved in the visible to near‐IR region. This novel architecture at the heterojunction opens new material design possibilities and represents an exciting route forward for hybrid photovoltaics.     

基于异频切换负载均衡算法研究与实现

在商用LTE基站系统中,小区之间存在业务量不均衡的情况,特别是热点区域,某些小区处于高负载状态,为了均衡小区的业务负载,引入了移动负载均衡(MLB)技术。选择合适用户(UE)切换到相邻低负载小区,从而有效地提高了整体网络资源效率和吞吐量,同时也能增强用户的性能体验。提出了一种以用户的RSRP和邻区PRB利用率为参数,基于UE业务量的异频切换负载均衡算法,选择出适量的UE切换到目标邻区中,从而达到网络负载均衡。根据实际基站调试结果表明,该算法能够快速精确地切换特定业务量的UE,明确了要卸载的业务量,并且提升了网络吞吐量和UE吞吐量。     

Microstructure and residual stress distribution of similar and dissimilar electron beam welds – Maraging steel to medium alloy medium carbon steel

The influence of parent metal heat treatment condition on the residual stress distribution in dissimilar metal welds of maraging steel to quenched and tempered medium alloy medium carbon steel has been investigated. It has been observed that the residual stress distribution would be more compressive if the maraging steel is in soft condition. This is attributed to stress absorbing nature of highly yielding soft maraging steel.     

Flexural creep of long fiber-reinforced thermoplastic composites: Effect of processing-dependent fiber variables on creep response

Flexural creep properties were studied as a function of fiber weight fraction and processing-induced fiber alignment in extrusion/compression-molded, long fiber-reinforced thermoplastic (LFT) nylon 6/6, polypropylene, and high-density polyethylene and their 10 wt.% and 40 wt.% E-glass fiber reinforced LFT composites. The residual fiber lengths and probability distribution parameters were near-equal, regardless of the initial fiber length and processing. Creep compliances decreased with increasing fiber weight fraction, and clear influence of fiber alignment was found in model parameters. Processing-induced fiber alignment imaged using X-ray radiography, was correlated with the creep compliances of strategically sectioned specimens, and tested as per ASTM D-2990. Longitudinal fibers aided in lowering the creep compliance, and the range in compliance decreased with lower preferential fiber alignment. Creep compliances from flexural creep tests and dynamic mechanical analysis/static creep tests were combined using time–temperature–stress superposition (TTSSP) to construct long-term master curves that correlated closely with long-term tests.     

Correction to: Enhanced critical current density of ex situ MgB2 via control of Mg assisted sintering

Journal of Materials Science: Materials in Electronics -     

Heavy metal accumulation in vegetables irrigated with water from different sources

The present study was carried out to assess levels of different heavy metals like iron, manganese, copper and zinc, in vegetables irrigated with water from different sources. The results indicated a substantial build-up of heavy metals in vegetables irrigated with wastewater. The range of various metals in wastewater-irrigated plants was 116–378, 12–69, 5.2–16.8 and 22–46 mg/kg for iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn), respectively. The highest mean levels of Fe and Mn were detected in mint and spinach, whereas the levels of Cu and Zn were highest in carrot. The present study highlights that both adults and children consuming vegetables grown in wastewater-irrigated soils ingest significant amount of these metals. However, the values of these metals were below the recommended maximum tolerable levels proposed by the [Joint FAO/WHO Expert Committee on Food Additives (1999). Summary and conclusions. In 53rd Meeting, Rome, June 1–10, 1999]. However, the regular monitoring of levels of these metals from effluents and sewage, in vegetables and in other food materials is essential to prevent excessive build-up of these metals in the food chain.     

大孔树脂固定化磷脂酶A1及其用于菜籽油脱胶工艺的优化

选择8种大孔树脂对磷脂酶A1进行固定化,结果表明,离子交换树脂D001的固定化效果最好,其优化的最佳条件为缓冲液pH5.0、酶添加量1.5mL/g、固定化时间4h,在该条件下获得的固定化酶活力为665.8U/g。将固定化酶用于菜籽油脱胶实验,经响应面优化确定最优脱胶条件为固定化酶添加量1.8g/kg、反应时间3.6h、反应温度51℃、反应pH5.5,在此条件下得到的脱胶油中磷含量为5.82mg/kg。将固定化酶重复脱胶5次后,仍保留初始酶活力的47.9%,脱胶油中磷含量为9.78mg/kg。     

Effect of superfine grinding on properties of <Emphasis Type="Italic">Vaccinium bracteatum</Emphasis> Thunb leaves powder

Vaccinium bracteatum Thunb, have been widely used in various traditional medicines and food products. The narrow and uniform particle size distribution in V. bracteatum Thunb leaves (VBTL) can be achieved through a new emerging type of foodstuff processing and superfine grinding. The VBTL powders were subjected to four particle sizes as followed: 300–125, 125–75, 75–40, and <40 μm. The VBTL powders were observed to be with smaller size and bulk density, greater surface area, tapped density and the angle of repose. Water solubility index, water holding capacity and total flavonoid extraction increased slightly with the decrease in particle size. Differential scanning calorimetry showed that the VBTL exhibiting particle size of <40 μm had the lowest peak temperature; whereas, powder with a particle size of 125–300 μm displayed the largest endothermic enthalpy. Our results of the properties of VBTL superfine powder supplied the basis for VBTL in potential industrial applications of foods.