Reduced graphene oxide modified melamine sponges filling with paraffin for efficient solar-thermal conversion and heat management

A novel type of reduced graphene oxide(rGO)modified melamine sponges(rGS)filling with paraffin(rGS-pf)is developed for efficient solar-thermal conversion and heat management.The microstructures,filling and holding capacity of paraffin in porous rGS,solar-thermal energy conversion and energy harvesting efficiency of the prepared rGS-pf have been investigated systematically.The content of rGO nanosheets coated on the skeletons of rGS-pf is only 0.11%,while the loading content of paraffin in the rGS-pf is as high as 97.53%.Based on the solar-thermal conversion property of rGO nanosheets in the rGS-pf and the heat storage ability of paraffin in the rGS-pf,the proposed rGS-pf provides excellent performance for heat management.The efficiency of solar-thermal conversion could reach up to 92.5%.The thermo-regulation provided by the proposed rGS-pf is real-time,repeatable and long-term stable.The results in this study provide valuable guidance for developing functional materials for efficient solarthermal conversion and heat management.

Heat Management System for Long-term Continuous Observation of Electronic Instrumentation in Deep Earth

Deep penetration into the Earth’s interior and direct monitoring of weak changes in physical fields and their cumulative processes and effects in the deep Earth can enhance the identification of deep Earth targets and deepen the degree of knowledge of the details of the deep Earth structure and deep processes(Moskvitch,2014),which is important for promoting the development of Earth system science.

Measurement of cryoelectronics heating using a local quantum dot thermometer in silicon

Silicon technology offers the enticing opportunity for monolithic integration of quantum and classical electronic circuits.However,the power consumption levels of classical electronics may compromise the local chip temperature and hence affect the fidelity of qubit operations.In the current work,a quantum-dot-based thermometer embedded in an industry-standard silicon fieldeffect transistor(FET)was adopted to assess the local temperature increase produced by an active FET placed in close proximity.The impact of both static and dynamic operation regimes was thoroughly investigated.When the FET was operated statically,a power budget of 45 nW at 100-nm separation was found,whereas at 216μm,the power budget was raised to 150μW.Negligible temperature increase for the switch frequencies tested up to 10 MHz was observed when operating dynamically.The current work introduced a method to accurately map out the available power budget at a distance from a solid-state quantum processor,and indicated the possible conditions under which cryoelectronics circuits may allow the operation of hybrid quantum-classical systems.

Progress and key challenges in catalytic combustion of lean methane

As a primary type of clean energy,methane is also the second most important greenhouse gas after CO_(2)due to the high global warming potential.Large quantities of lean methane(0.1–1.0 vol%)are emitted into the atmosphere without any treatment during coal mine,oil,and natural gas production,thus leading to energy loss and greenhouse effect.In general,it is challenging to utilize lean methane due to its low concentration and flow instability,while catalytic combustion is a vital pathway to realize an efficient utilization of lean methane owing to the reduced emissions of polluting gases(e.g.,NOxand CO)during the reaction.In particular,to efficiently convert lean methane,it necessitates both the designs of highly active and stable heterogeneous catalysts that accelerate lean methane combustion at low temperatures and smart reactors that enable autothermal operation by optimizing heat management.In this review,we discuss the in-depth development,challenges,and prospects of catalytic lean methane combustion technology in various configurations,with particular emphasis on heat management from the point of view of material design combined with reactor configuration.The target is to describe a framework that can correlate the guiding principles among catalyst design,device innovation and system optimization,inspiring the development of groundbreaking combustion technology for the efficient utilization of lean methane.

Research on a simulated 60 kW PEMFC cogeneration system for domestic application

The electrical and thermal performances of a simulated 60 kW Proton Exchange Membrane Fuel Cell (PEMFC) cogeneration system are first analyzed and then strategies to make the system operation stable and efficient are developed. The system configuration is described first, and then the power response and coordination strategy are presented on the basis of the electricity model. Two different thermal models are used to estimate the thermal performance of this cogeneration system, and heat management is discussed. Based on these system designs, the 60 kW PEMFC cogeneration system is analyzed in detail. The analysis results will be useful for further study and development of the system.

Investigation of heat sink of endothermic hydrocarbon fuels

Endothermic hydrocarbon fuels are advanced coolants for high-temperature structures of spacecraft. No data of tested-cooling-ability of endothermic fuels have been broadly discussed in literature. In this work a high-temperature flow calorimeter was designed, and the cooling capacity of six different hydrocarbon fuels were measured. Experimental results showed that these hydrocarbon fuels have capacity for cooling high-temperature structures, and that the cooling capacity of fuel N-1 can reach 3.15 M J/kg, which can nearly satisfy the requirement of thermal management for a Mach 3 cruise aircraft, whose heat sink requirement is about 3.5 M J/kg. The endothermic velocity of hydrocarbon fuels was also measured by the calorimeter.

Robust,Breathable and Flexible Smart Textiles as Multifunctional Sensor and Heater for Personal Health Management

Smart textiles with high sensitivity and rapid response for various external stimuli have gained tremendous attentions in human healthcare monitoring,personal heat management,and wearable electronics.However,the current smart textiles only acquire desired signal passively,regularly lacking subsequent on-demand therapy actively.Herein,a robust,breathable,and flexible smart textiles as multi-function sensor and wearable heater for human health monitoring and gentle thermotherapy in real time is constructed.The composite fiber as strain sensor(CFY@PU)was fabricated via warping carbon fiber yarns(CFY)onto polyurethane fibers(PU),which endowed composite fiber with high conductivity,excellent sensitivity(GF=76.2),and fantastic dynamic durability(7500 cycles)in strain sensing.In addition,CFY@PU can detect various degrees of human movements such as elbow bending,swallowing and pulse,which can provide effective information for disease diagnosis.More surprisingly,weaving CFY@PU into a fabric can assemble highly sensitive pressure sensor for remote communication and information encryption.Warping CFY onto Kevlar would obtain temperature-sensitive composite fiber(CFY@Kevlar)as temperature sensor and wearable heater for on-demand thermotherapy,which provided unique opportunities in designing smart textiles with ultrahigh sensitivity,rapid response,and great dynamic durability.

Nano-enabled solar driven-interfacial evaporation:Advanced design and opportunities

Solar-driven interfacial evaporation(SDIE)is emerging as a promising pathway to solving the worldwide water shortage and water pollution.Nanomaterials(e.g.,plasmonic metals,inorganic/organic semiconductors,and carbon nanomaterials)and related nanochemistry have attracted increasing attention for the solar-to-vapor process in terms of broadband absorption,electronic structure adjustment,and surface/interface chemistry manipulation.Furthermore,the assembly of nanomaterials can contribute to the mass transfer,heat management,and enthalpy regulation of water during solar evaporation.To date,numerous nano-enabled materials and structures have been developed to improve the solar absorption,heat management(i.e.,heat confinement and heat transfer),and water management(i.e.,activation,evaporation,and replenishment).In this review,we focus on a systematical summary about the composition and structure engineering of nanomaterials in SDIE,including size and morphology effects,nanostructure optimizations,and structure-property relationship decoupling.This review also surveys recent advances in nanochemistry(e.g.,preparation chemistry and structural chemistry)deployed to conceptual design of nanomaterials.Finally,the key challenges and future perspectives of nanomaterials for solar evaporation are overviewed.This review aims at providing guidance for the design and construction of nanomaterials for high-efficiency SDIE on the basis of the aspects of materials science and chemical engineering.

Fiber‑Shaped Fluidic Pumps for Wearable Applications

Soft fluidic devices are important for wearable applications involving mass and heat transfer.Based on charge injection electrohydrodynamics,a fluidic fiber pump made of polyurethane and copper wires has been reported to show outstanding performances in terms of pressure,flow rate and power density.Its flexible fiber shape allows integration compatible with textiles,opening new possibilities in the ever-growing field of wearable technology.