Layered Structural PBAT Composite Foams for Efficient Electromagnetic Interference Shielding

The utilization of eco-friendly,lightweight,high-efficiency and high-absorbing electromagnetic interference(EMI)shielding composites is imperative in light of the worldwide promotion of sustainable manufacturing.In this work,magnetic poly(butyleneadipate-coterephthalate)(PBAT)microspheres were firstly synthesized via phase separation method,then PBAT composite foams with layered structure was constructed through the supercritical carbon dioxide foaming and scraping techniques.The merits of integrating ferroferric oxideloaded multi-walled carbon nanotubes(Fe3O4@MWCNTs)nanoparticles,a microcellular framework,and a highly conductive silver layer have been judiciously orchestrated within this distinctive layered configuration.Microwaves are consumed throughout the process of“absorption-reflection-reabsorption”as much as possible,which greatly declines the secondary radiation pollution.The biodegradable PBAT composite foams achieved an EMI shielding effectiveness of up to 68 dB and an absorptivity of 77%,and authenticated favorable stabilization after the tape adhesion experiment.

Shell characterization and effects on cavity volume of wild Jinjiang oyster Crassostrea ariakensis in different estuaries of China

Jinjiang oyster Crassostrea ariakensis,a species with economic and ecological value,is distributed along the estuaries and coasts of East Asia.With the decline in natural resources,the conservation and aquaculture of this species is urgent.However,studies characterizing their shell shape remain scarce.We investigated the morphological differences in the shells of wild Jinjiang oysters from six populations(Qinzhou,Shanghai,Nantong,Qingdao,and Binzhou hard or muddy bottom)along the coast of China.The color of the shell and adductor muscle scar showed associations with temperature gradient along its geographical distribution.Oyster shape was defined by shell height to shell length ratio,and the ratio varies among geographic locations of the populations.They were found nearly round(Qinzhou and Nantong populations),oval(Qingdao and Binzhou populations),or water-droplet-shaped(Shanghai population).Binzhou populations living on muddy substrates are more elongated than those on hard substrate.In addition,we developed a method to measure the cavity volume in oysters.Correlation and path analysis showed that shell height significantly influenced cavity volume.The synergistic effect of the two factors(the height,length,and width of the shell in pairs)on the cavity volume resulted in differences between northern and southern groups:samples from the southern group(Qinzhou and Shanghai)showed correlation between shell height and shell width,while those from the northern group(Nantong,Qingdao,and Binzhou)showed correlation between shell height and shell length.All populations showed significant correlation between shell height and cavity height,and shell length and cavity length,while the correlation between shell width and cavity width was minimal,which may have been resulted from uneven shell thickness.The linear equation for shell height and cavity volume under different ratios of shell height to length was obtained.In this study,we determined that shell height has the most influence on cavity volume,and specific cavity volume fitting linear equations are given for different shell types,which may provide a reference for future oyster breeding for shell shaping.

Resting-state connectivity in the default mode network and insula during experimental low back pain

Functional magnetic resonance imaging studies have shown that the insular cortex has a signif- icant role in pain identification and information integration, while the default mode network is associated with cognitive and memory-related aspects of pain perception. However, changes in the functional connectivity between the defauk mode network and insula during pain remain unclear. This study used 3.0 T functional magnetic resonance imaging scans in 12 healthy sub- jects aged 24.8 ± 3.3 years to compare the differences in the functional activity and connectivity of the insula and default mode network between the baseline and pain condition induced by intramuscular injection of hypertonic saline. Compared with the baseline, the insula was more functionally connected with the medial prefrontal and lateral temporal cortices, whereas there was lower connectivity with the posterior cingulate cortex, precuneus and inferior parietal lobule in the pain condition. In addition, compared with baseline, the anterior cingulate cortex exhibited greater connectivity with the posterior insula, but lower connectivity with the anterior insula, during the pain condition. These data indicate that experimental low back pain led to dysfunction in the connectivity between the insula and default mode network resulting from an impairment of the regions of the brain related to cognition and emotion, suggesting the impor- tance of the interaction between these regions in pain processing.

Defect passivation by nontoxic biomaterial yields 21% efficiency perovskite solar cells

Defect passivation is one of the most important strategies to boost both the efficiency and stability of perovskite solar cells(PSCs).Here,nontoxic and sustainable forest-based biomaterial,betulin,is first introduced into perovskites.The experiments and calculations reveal that betulin can effectively passivate the uncoordinated lead ions in perovskites via sharing the lone pair electrons of hydroxyl group,promoting charge transport.As a result,the power conversion efficiencies of the p-i-n planar PSCs remarkably increase from 19.14%to 21.15%,with the improvement of other parameters.The hydrogen bonds of betulin lock methylamine and halogen ions along the grain boundaries and on the film surface and thus suppress ion migration,further stabilizing perovskite crystal structures.These positive effects enable the PSCs to maintain 90%of the initial efficiency after 30 days in ambient air with 60%±5%relative humidity,75%after 300 h aging at 85℃,and 55%after 250 h light soaking,respectively.This work opens a new pathway for using nontoxic and low-cost biomaterials from forest to make highly efficient and stable PSCs.

Surface Passivation and Energetic Modification Suppress Nonradiative Recombination in Perovskite Solar Cells

Surface passivation via post-treatment is an important strategy for improving power conversion efficiency and operational stability of perovskite solar cells.However,so far the interaction mechanisms between passivating additive and perovskite are not well understood.Here,we report the atomic-scale interaction of surface passivating additive 2,2-difluoroethylammonium bromine(2FEABr)on the MAPbI_(3).It is found that the bulky 2FEA+cations tend to distribute at film surface,while the Br−anions diffuse from surface into bulk.A combination of 19F,207Pb,and 2H solid-state NMR further reveal the Br−anions’partial substitution for the I−sites,the restricted motion of partial MA+cations,and the firmed perovskite lattices,which would improve charge transport and stability of the perovskite films.Optical spectroscopy and ultraviolet photoelectron spectroscopy demonstrate that the 2FEABr induced surface passivation and energetic modification suppress the nonradiative recombination loss.These findings enable the efficiency of the p-i-n structured PSC significantly increasing from 19.44 to 21.06%,accompanied by excellent stability.Our work further establishes more knowledge link between passivating additive and PSC performance.

Progress in Research on the Impacts of Global Climate Change on Winter Ski Tourism

滑雪旅游上的全球气候变化的影响，重重地取决于气候条件，逐渐地获得了海外的担心。这篇论文系统地通过以前的研究的广泛的合成总结了相关研究想法，使用的技术方法，和获得的成就。而且，在最近的研究的主要缺点和限制被削尖以便为我们的中国调查者介绍一本有用参考书。它显示温暖的未来气候将引起 skiable 区域的损失，在许多低高度和低纬度滑雪板滑雪季节和滑雪来宾的锋利的落下弄短求助。论文最后强调未来研究应该对加强学科交差的合作给予特别注意并且在旅游流动上关于导致气候的环境变化的影响考虑更多的因素。在计划的未来滑雪胜地和管理，全球气候变化的可能的影响应该被考虑。引证杨， J. ，和 C。苍白， 2010：在关于冬季滑雪旅游的关于全球气候变化的影响的研究进行。副词。Clim。变化物件， 1， doi：10.3724/SP .J.1248.2010.00055。

Investigating the reason for high FF from ternary organic solar cells

Organic solar cells(OSCs)have attracted huge attention because of their unique merits[1−3].In last few years,thanks to the design of new materials and device engineering,the power conversion efficiencies(PCEs)of OSCs have surpassed 18%[4−8].The PM6:Y6 cells are efficient binary cells,offering high PCEs over 16%[9−11].The high performance originates from the efficient free charge generation and the ground state dipole field at the donor-acceptor interface that promotes the exciton dissociation[12].

Dynamic performance and energy efficiency of reflective and insulative composite coating on building exterior wall

Reflective and insulative composite coatings are a new energy-saving material with high solar reflectance and extremely low thermal conductivity for buildings.The optimization and impact of high solar reflectance and low thermal conductivity on the insulating capacity of walls remain uncertain.This work investigates the dynamic thermal performance and energy efficiency of a reflective and insulative composite coating in regions with hot summer and warm winter.A simplified thermal resistance-heat capacitance model of an exterior building wall is established to predict thermal performance.The dynamic temperature and heat flow of the wall are predicted to reduce heat loss through the interior surface of the wall and compared to the conventional coating.The specific impact of the thermal conductivity and solar reflectance of the coating on the heat loss is further investigated to minimize heat loss of the wall.This research shows that the composite coating shows better performance on adjusting outdoor climate change than the other coating.Compared with cement,it reduces the maximum temperature of the exterior surface of the wall by 7.45°C,and the heat loss through the interior surface of the wall by 38%.The heat loss is reduced with the increase of solar reflectance and the reduction of thermal conductivity.The results can provide a useful reference and guidance for the application of reflective and insulative composite coating on building exterior wall to promote their energy-saving use on building envelopes.

AICellCounter:A Machine Learning-Based Automated Cell Counting Tool Requiring Only One Image for Training

Dear Editor,To decipher brain functions,brain cells are generally prelabeled and then imaged using a high-resolution confocal system,and manual or automatic counting methods are widely used in the quantitative and semiquantitative analysis of these confocal images.Therefore,cell counting becomes a bottleneck in efficient analysis because manual counting is laborious and time-consuming.Therefore,an accurate and user-friendly automated cell counting tool is needed for biological researchers.

Sharp interface direct forcing immersed boundary methods： A summary of some algorithms and applications

Body-fitted mesh generation has long been the bottleneck of simulating fluid flows involving complex geometries. Immersed boundary methods are non-boundary-conforming methods that have gained great popularity in the last two decades for their simplicity and flexibility, as well as their non-compromised accuracy. This paper presents a summary of some numerical algori- thms along the line of sharp interface direct forcing approaches and their applications in some practical problems. The algorithms include basic Navier-Stokes solvers, immersed boundary setup procedures, treatments of stationary and moving immersed bounda- ries, and fluid-structure coupling schemes. Applications of these algorithms in particulate flows, flow-induced vibrations, biofluid dynamics, and free-surface hydrodynamics are demonstrated. Some concluding remarks are made, including several future research directions that can further expand the application regime of immersed boundary methods.

A sharp interface approach for cavitation modeling using volume-of-fluid and ghost-fluid methods

This paper describes a novel sharp interface approach for modeling the cavitation phenomena in incompressible viscous flows. A one-field formulation is adopted for the vapor-liquid two-phase flow and the interface is tracked using a volume of fluid（VOF） method. Phase change at the interface is modeled using a simplification of the Rayleigh-Plesset equation. Interface jump conditions in velocity and pressure field are treated using a level set based ghost fluid method. The level set function is constructed from the volume fraction function. A marching cubes method is used to compute the interface area at the interface grid cells. A parallel fast marching method is employed to propagate interface information into the field. A description of the equations and numerical methods is presented. Results for a cavitating hydrofoil are compared with experimental data.

Prefrontal cortical circuits in anxiety and fear:an overview

Pathological anxiety is among the most difficult neuropsychiatric diseases to treat pharmacologically,and it represents a major societal problem.Studies have implicated structural changes within the prefrontal cortex(PFC)and functional changes in the communication of the PFC with distal brain structures in anxiety disorders.Treatments that affect the activity of the PFC,including cognitive therapies and transcranial magnetic stimulation,reverse anxiety-and fear-associated circuit abnormalities through mechanisms that remain largely unclear.While the subjective experience of a rodent cannot be precisely determined,rodent models hold great promise in dissecting well-conserved circuits.Newly developed genetic and viral tools and optogenetic and chemogenetic techniques have revealed the intricacies of neural circuits underlying anxiety and fear by allowing direct examination of hypotheses drawn from existing psychological concepts.This review focuses on studies that have used these circuit-based approaches to gain a more detailed,more comprehensive,and more integrated view on how the PFC governs anxiety and fear and orchestrates adaptive defensive behaviors to hopefully provide a roadmap for the future development of therapies for pathological anxiety.

Cooling load characteristics of indoor spaces conditioned by decoupled radiant cooling unit with low radiant temperature

Decoupled radiant cooling units(DRCUs)are capable of increasing the cooling capacity without increasing condensation risks even using a much lower cooling temperature than conventional radiant cooling units(CRCUs).However,it is unclear whether DRCUs using low radiant cooling temperature will increase the cooling load of the conditioned indoor spaces.In this study,the cooling load characteristics of a thermal chamber conditioned by a DRCU was investigated through developing a steady-state analysis model suitable for both DRCUs and CRCUs.The total/radiative heat flux,as well as the heat exchange with a thermal manikin and walls were analysed under different surface temperatures of DRCUs.The effect of the emissivity of the thermal chamber’external wall on the cooling load was also investigated.Results indicated that the cooling load under the DRCU was slightly smaller than that under the CRCU when the same operative environment was created.Decreasing the infrared emissivity of the exterior wall’s inner surface could lead to a significant decrease in the cooling load for both the DRCU and CRCU.By decreasing the wall emissivity from 0.9 to 0.1,the total cooling load of the DRCU can be decreased by 8.4%and the heat gain of the exterior wall decreased by 21.6%.This study serves as a reference for developing the analysis model and understanding the load characteristics when DRCUs are used to create the thermal environment for indoor spaces.