摘要：A square-shaped heat flux cloak and a square-shaped heat flux concentrator have been designed the- oretically according to the invariance symmetry of steady state thermal conductive equation. The direction of heat flux in these devices can be modulated as desired. Using the method of coordinate transformation, the inhomogeneous and anisotropic thermal conductivity in the transformation region have been acquired. Two-dimensional finite element simulations were performed to confirm the theoretical results.

摘要：The self-dissipation and attenuation capacity of materials play an important role in realizing efficient electromagnetic absorption,in this case,the roles of macroscopic composition and micro-structure should be emphasized simultaneously in the reasonable design of microwave *** that,Fe_(3)N alloy embedded in two-dimensional porous carbon composites were fabricated via facile sol-gel and sacrificial template ***,the magnetic/dielectric materials combination and porous structure introduction are conductive to the optimization of impedance matching property,as result of the enhancement of microwave absorption *** addition,sufficient magnetic loss capacity,strong conductivity as well as polarization attenuation bring about the outstanding microwave absorbing performance with an effective absorption bandwidth of 6.76 GHz and a minimum reflection loss value of-65.6 d *** is believed that this work not only lay a foundation to achieve microwave response materials in a wide frequency range,but also emphasize the significant role of the component selection and structural design.

摘要：Solid oxide fuel cells(SOFCs)have attracted a great deal of interest because they have the highest efficiency without using any noble metal as catalysts among all the fuel cell ***,traditional SOFCs suffer from having a higher volume,current leakage,complex connections,and difficulty in gas *** solve these problems,Rolls-Royce has fabricated a simple design by stacking cells in series on an insulating porous support,resulting in the tubular segmented-in-series solid oxide fuel cells(SIS-SOFCs),which achieved higher output *** work systematically reviews recent advances in the structures,preparation methods,perform-ances,and stability of tubular SIS-SOFCs in experimental and numerical ***,the challenges and future development of tubular SIS-SOFCs are also *** findings of this work can help guide the direction and inspire innovation of future development in this field.

摘要：Wind machines have been increasingly applied to prevent frost damage through airflow disturbance in tea fields and *** impeller is the most important component of the ***,there are few studies on customized impeller design or airflow disturbance *** objective of this study was to design a new impeller for frost protection wind machines based on reverse engineering and CFD *** characteristic parameters of an impeller include blade cross-section shape,installation angle,sweep angle,hub ratio and blade *** optimal combination of the above parameters was obtained through the simulation of the impeller’s aerodynamic *** tests were conducted in a tea field to evaluate airflow disturbance performance of the designed *** result shows that at a certain rotation speed and rotation diameter,the optimal combination of impeller parameters was:single arc cross-section ofϕ2400 mm,installation angle of 15°,sweep angle of 87°,hub ratio of 0.3 and blade number of 4,of which the impeller could achieve the highest usage of 0.56,the least consumed power of 1.363 kW and more uniform distribution of surface pressure on the windward *** with other commercial frost protection wind machines,the maximum airflow velocity of the developed impeller was higher at 12 m in front of *** probability of airflow velocity above 3.0 m/s within 30 min was the highest(71.7%),indicating its improvement of airflow *** swing the new impeller could cover an effective area of 300 m2,which was similar to that of the commercial ones.

摘要：Acoustic one-way manipulations have recently attracted significant attention due to the deep implications in many diverse fields such as biomedical imaging and ***,the previous mechanisms of asymmetric manipulation of airborne sound need to use elaborate heavyweight structures and only work in certain frequency *** propose a mechanism for designing an ultra-lightweight and optically transparent structure with asymmetric transmission property for normally incident plane *** of fabricating solids into complicated artificial structures with limited bandwidth and heavy asymmetric shape which allows the incident plane wave weight,we simply use xenon to fill a spatial region of to pass along one direction while reflecting the reversed wave regardless of *** demonstrate both analytically and numerically its effectiveness of producing highly-asymmetric transmission within an ultra-broad *** design offers new possibility for the design of one-way devices and may have far-reaching impact on various scenarios such as noise control.

摘要：Aiming to investigate the mix design of eco-friendly UHPC with supplementary cementitious materials and coarser aggregates, we comprehensively studied the workability, microstructure, porosity, compressive strength, flexural strength, and Young’s modulus of UHPC. Relationship between compressive strength and Young’s modulus was obtained eventually. It is found that the compressive strength, flexural strength, and Young’s modulus of UHPC increase by 19.01%, 10.81%, and 5.99%, respectively, when 40 wt% cement is replaced with supplementary cementitious materials. The relationship between compressive strength and Young’s modulus of UHPC is an exponential form.

摘要：p-Menthane type monoterpene derivatives were identified as bio-based compounds with high herbicidal activities. In order to search novel p-menthane type monoterpene derivatives in good performance, a series of novel cis-p-menthane type Schiff base derivatives were designed and synthesized. All target products were easily available novel compounds and characterized by FT-IR,^1H NMR,^13 C NMR and ESI＋-MS. Their pre-emergence herbicidal activities against annual ryegrass were evaluated. The bioassays indicated that most of the target compounds displayed excellent herbicidal activities in pre-emergence treatment.

摘要：Interfacial solar steam generation is an efficient water evaporation technology which has promising applications in desalination,sterilization,water purification and treatment.A common component of evaporator design is a thermal-insulation support placed between the photothermal evaporation surface and bulk *** configuration,common in 2-dimensional(2 D)evaporation systems,minimizes heat loss from evaporation surface to bulk water,thus localizing the heat on the evaporation surface for efficient *** design is subsequently directly adopted for 3-dimensional(3 D)evaporators without any consideration if it is ***,unlike 2 D solar evaporators,the 3 D evaporators can also harvest additional energy(other than solar light)from the air and bulk water to enhance evaporation *** this scenario,the use of thermal insulator support is not proper since it will hinder energy extraction from ***,the traditional 3 D evaporator configuration was completely redesigned by using a highly thermally conductive material,instead of a thermal insulator,to connect evaporation surfaces and the bulk *** higher evaporation rates were achieved by this strategy,owing to the rapid heat transfer from the bulk water to the evaporation *** and outdoor tests both confirmed that evaporation performance could be significantly improved by substituting a thermal insulator with thermally conductive *** findings will redirect the future design of 3 D photothermal evaporators.

摘要：How nonlinear joints affect the response of large space structures is an important problem to *** this paper,a multi-harmonic equivalent modeling method is presented to establish a frequency-domain model of planar repetitive structures with nonlinear ***,at the local level,the nonlinear joint is modeled by the multi-harmonic describing function *** element of the hybrid beam is obtained by the dynamic condensation of the beam-joint ***,at the global level,the displacement-equivalence method is used to model the multi-harmonic Euler continuum beam equivalent to the planar repetitive ***,the pseudo-arc-length continuation method is applied to track the multi-harmonic trajectory of ***,an experiment is conducted to validate the correctness of the modeling method,considering the effect of hanging rope and air *** the numerical studies,several simulation results indicate the similarity of response between a single-degree-of-freedom system with a single nonlinear joint and the system of the planar repetitive structure with a large number of nonlinear ***,the component of higher-order harmonics is shown to be important for predicting the resonance frequencies and amplitudes.

摘要：Interfacial solar-steam generation is a promising and cost-effective technology for both desalination and wastewater *** process uses a photothermal evaporator to absorb sunlight and convert it into heat for water *** solar-steam generation can be somewhat inefficient due to energy losses via conduction,convection and ***,efficient energy management is crucial for optimizing the performance of solar-steam ***,via elaborate design of the configuration of photothermal materials,as well as warm and cold evaporation surfaces,performance in solar evaporation was significantly *** was achieved via a simultaneous reduction in energy loss with a net increase in energy gain from the environment,and recycling of the latent heat released from vapor condensation,diffusive reflectance,thermal radiation and convection from the evaporation ***,by using the new strategy,an evaporation rate of 2.94 kg m^-2 h^-1,with a corresponding energy efficiency of solar-steam generation beyond theoretical limit was achieved.