Oxidative Molecular Layer Deposition Tailoring Eco-Mimetic Nanoarchitecture to Manipulate Electromagnetic Attenuation and Self-Powered Energy Conversion

Advanced electromagnetic devices,as the pillars of the intelligent age,are setting off a grand transformation,redefining the structure of society to present pluralism and diversity.However,the bombardment of electromagnetic radiation on society is also increasingly serious along with the growing popularity of"Big Data".Herein,drawing wisdom and inspiration from nature,an eco-mimetic nanoarchitecture is constructed for the first time,highly integrating the advantages of multiple components and structures to exhibit excellent electromagnetic response.Its electromagnetic properties and internal energy conversion can be flexibly regulated by tailoring microstructure with oxidative molecular layer deposition(oMLD),providing a new cognition to frequency-selective microwave absorption.The optimal reflection loss reaches≈−58 dB,and the absorption frequency can be shifted from high frequency to low frequency by increasing the number of oMLD cycles.Meanwhile,a novel electromagnetic absorption surface is designed to enable ultra-wideband absorption,covering almost the entire K and Ka bands.More importantly,an ingenious self-powered device is constructed using the eco-mimetic nanoarchitecture,which can convert electromagnetic radiation into electric energy for recycling.This work offers a new insight into electromagnetic protection and waste energy recycling,presenting a broad application prospect in radar stealth,information communication,aerospace engineering,etc.

Adoption of Improved Biomass Cook Stoves: Case Study of Baringo and West Pokot Counties in Kenya

Biomass cookstove improvement has been a global active research area for many decades and has resulted into much progress towards cleaner and more efficient energy conversion cooking devices. Irrespective of the perfection and development of improved cookstoves, many households in Kenya are still using three stone cookstoves. In Baringo County, 71.8% used three stone cookstoves. The focus of research needs to change towards adoption of improved cook stoves. A cross-sectional survey was conducted in rural, peri-urban and urban households regarding current cookstoves types in relation to fuel use categorized as improved and un-improved in Baringo and West Pokot counties. Biomass was the primary fuel in the two counties used in the form of firewood and charcoal at average of 70% and 26% respectively. The main un-improved cookstoves in the two counties were three stone and metallic jiko. The two were commonly used in Baringo County with 28.5% of the households using metallic stove. Whereas in West Pokot, Chepkube was the main cookstove used for cooking at 47.8% seconded by improved three stone at 36.6%. The use of un-improved cookstove was popular in Baringo County at 77.6% while infamous in West Pokot County at 21.7%. The results showed that West Pokot County is more conscious to energy related issues unlike Baringo County. The difference in dynamic of the two Counties in terms of land ownership, access to biofuel, social groupings, availability of cookstove installers and improved jikos could be the reason.

Ferromagnetic resonance frequency shift model of laminated magnetoelectric structure tuned by electric field

Based on Smith-Beljers theory and classical laminate theory, an explicit model is proposed for the ferromagnetic resonance （FMR） frequency shift of a stress-mediumed laminated magnetoelectric structure tuned by an electric field. This model can effectively predict the experimental phenomenon that the FMR frequency increases under a parallel magnetic field and decreases under a perpendicular magnetic field when the electric field ranges from - 10 kV/m to 10 kV/m. Besides, this theory further shows that the FMR frequency increases monotonically as the angle between the direction of the external magnetic field and the outside normal direction of the laminated structure increases, and the frequency will increase as great as 7 GHz. In addition, when the angle reaches a certain critical value, the external electric field fails to tune the FMR frequency. When the angle is above the critical value, the increase of the electric field induces the FMR frequency to increase, and the opposite scenario happens when it is below the critical value. When the angle is 90~ （parallel magnetic field）, the FMR frequency is the most sensitive to the change of the electric field.

Integrated solar capacitors for energy conversion and storage

Solar energy is one of the most popular clean energy sources and is a promising alternative to fulfill the increasing energy demands of modem society. Solar cells have long been under intensive research attention for harvesting energy from sunlight with a high power-conversion efficiency and low cost. However, the power outputs of photovoltaic devices suffer from fluctuations due to the intermittent instinct of the solar radiation. Integrating solar cells and energy- storage devices as self-powering systems may solve this problem through the simultaneous storage of the electricity and manipulation of the energy output. This review the research progress in the integration of new-generation solar cells with supercapacitors, with emphasis on the structures, materials, performance, and new design features. The current challenges and future prospects are discussed with the aim of expanding research and development in this field.

Two-dimensional Janus van der Waals heterojunctions:A review of recent research progresses

Two-dimensional Jamus van der Waals(vdW)heterojunctions,referring to the junction containing at least one Janus material,are found to exhibit tuneable electronic structures,wide light adsorption spectra,controllable contact resistance,and sufficient redox potential due to the intrinsic polarization and unique interlayer coupling.These novel structures and properties are promising for the potential applications in eleetronics and energy conversion devices.To provide a comprehensive picture about the research progress and guide the following investigations,here we summarize their fundamental properties of different types of two-dimensional Janus vdW heterostruct ures including electronic struc-ture,interface contact and optical properties,and discuss the potential applications in electronics and energy conversion devices.The further challenges and possible research directions of the novel heterojunctions are discussed at the end of this review.