Soft,body conformable electronics for thermoregulation enabled by kirigami

The application of thermoelectric devices(TEDs)for personalized thermoregulation is attractive for saving energy while balancing the quality of life.TEDs that directly attach to human skin remarkably minimized the energy wasted for cooling the entire environment.However,facing the extreme dynamic geometry change and strain of human skin,conventional TEDs cannot align with the contour of our bodies for the best thermoregulation effect.Hence,we designed a kirigami-based wearable TED with excellent water vapor permeability,flexibility,and conformability.Numerical analysis and experimental results reveal that our product can withstand various types of large mechanical deformation without circuit rupture.The stated outcome and proposed facile approach not only reinforce the development of wearable TEDs but also offer an innovative opportunity for different electronics that require high conformability.

Au-Ag alloy nanoparticles with tunable cavity for plasmon-enhanced photocatalytic H2 evolution

Au-Ag alloy nanoparticles with different cavity sizes have great potential for improving photocatalytic performance due to their tunable plasmon effect.In this study,galvanic replacement was combined with co-reduction with the reaction kinetics processes regulated to rapidly synthesize Au-Ag hollow alloy nanoparticles with tunable cavity sizes.The position of the localized surface plasmon resonance(LSPR)peak could be effectively adjusted between 490 nm and 713 nm by decreasing the cavity size of the Au-Ag hollow nanoparticles from 35 nm to 20 nm.The plasmon-enhanced photocatalytic H2 evolution of alloy nanoparticles with different cavity sizes was investigated.Compared with pure P25(TiO2),intact and thin-shelled Au-Ag hollow nanoparticles(HNPs)-supported photocatalyst exhibited an increase in the photocatalytic H2 evolution rate from 0.48μmol h^−1 to 4μmol h^−1 under full-spectrum irradiation.This improved photocatalytic performance was likely due to the plasmon-induced electromagnetic field effect,which caused strong photogenerated charge separation,rather than the generation of hot electrons.

Model predictive control of rigid spacecraft with two variable speed control moment gyroscopes

In this paper, an attitude maneuver control problem is investigated for a rigid spacecraft using an array of two variable speed control moment gyroscopes （VSCMGs） with gimbal axes skewed to each other. A mathematical model is constructed by taking the spacecraft and the gyroscopes together as an integrated system, with the coupling interaction between them considered. To overcome the singular issues of the VSCMGs due to the conventional torque-based method, the first-order derivative of gimbal rates and the second-order derivative of the rotor spinning velocity, instead of the gyroscope torques, are taken as input variables. Moreover, taking external disturbances into account, a feedback control law is designed for the system based on a method of nonlinear model predictive control （NMPC）. The attitude maneuver can be realized fast and smoothly by using the proposed controller in this paper.

Mass production of Li Fe PO_4/C energy materials using Fe–P waste slag

To effectively solve the agglomeration problems in the solid state reaction process,pre-adding glucose is adopted to the synthesis of Li Fe PO4/C energy materials using Fe–P waste slag. The average particle grain size of Li FeP O4/C decreases,and the impurities in Li Fe PO4/C composites reduce to a great extent. It makes great sense to the mass industrial production. The optimum synthesis conditions determined in this work are based on the orthogonal experiments. The samples synthesized in a scale of 500 g exhibit high purity,excellent electrochemical performance,high reaction activity,good reversibility,and low polarization level.The discharge capacities are 145,134,117,and 102 m Ah/g at the current densities of 0.1 C,0.2 C,0.5 C and1 C,respectively. This work puts forward a practical suggestion for mass producing environmental benign and low cost Li FeP O4/C as cathode materials of lithium ion batteries.

Thin,soft,skin-integrated electronics for real-time and wireless detectionof uricacid in sweat

Wearable sweat sensors are gaining significant attention due to their unparalleled potential for noninvasive health monitoring.Sweat,as a kind of body fluid,contains informative physiological indicators that are related to personalized health status.Advances in wearable sweat sampling and routing technologies,flexible,and stretchable materials,and wireless digital technologies have led to the development of integrated sweat sensors that are comfortable,flexible,light,and intelligent.Herein,we report a flexible and integrated wearable device via incorporating a microfluidic system and a sensing chip with skin-integrated electronic format toward in-situ monitoring of uric acid(UA)in sweat that associates with gout,cardiovascular,and renal diseases.The microfluidic system validly realizes the real-time capture perspiration from human skin.The obtained detection range is 5-200μM and the detection limit is 1.79μM,which offers an importance diagnostic method for clinical relevant lab test.The soft and flexible features of the constructed device allows it to be mounted onto nearly anywhere on the body.We tested the sweat UA in diverse subjects and various body locations during exercise,and similar trends were also observed by using a commercial UA assay kit.

Environmentally benign chitosan as reductant and supporter for synthesis of Ag/AgCI/chitosan composites by one-step and their photocatalytic degradation performance under visible-light irradiation

A novel Ag/AgCl/chitosan composite photocatalyst was successfully prepared by a simple one-step method. During this progress, environmentally benign chitosan not only served as reductant to reduce Ag＋ to Ag0 species, but also acted as supporter for Ag/AgCI nanoparticles. XRD, SEM, EDX, UV-vis DRS and XPS were employed to characterize the as-prepared simples. SEM images of Ag/AgCI/chitosan composites revealed that Ag/AgCI nanoparticles were successfully loaded onto chitosan without obvious aggregation. All Ag/AgCI/chitosan composites exhibited efficient photocatalytic activity for the degradation of rhodamine B （RhB） under visible-light irradiation. The result of photocatalytic degradation experiment indicated that 20% of the mass ratio of AgCI to chitosan was the optimum, and after 40 min photocatalytic reaction, the degradation rate reached about 96%.

A novel black TiO2/ZnO nanocone arrays heterojunction on carbon cloth for highly efficient photoelectrochemical performance

ZnO nanocone arrays(NCAs)decorated with black TiO2 nanoparticles(BTiO2 NPs)were uniformly anchored on the surface of carbon cloth(CC)directly by a simply electrochemical deposition method.Thus a novel B-TiO2 NPs/ZnO NCAs-CC hierarchical heterostructure was formed.It displayed superior performance and achieved a higher photocurrent over 0.4 mA·cm^-2 before the onset of the dark current,attributed to the separation of the photogenerated electron-hole pair.Based on the B-TiO2 NPs/ZnO NCAs-CC heterostructure,the catalyst was fabricated for promoting the separation of charge carriers.Moreover,the introduction of Ti^3+ and oxygen vacancies on the surface of TiO2 NPs expanded the absorption band edge and enhanced the electrical conductivity as well as the charge transportation on the catalytic surface.It indicates that the B-TiO2 NPs/ZnO NCAs-CC composite is beneficial to the improvement of the photoelectrochemical(PEC)activity.