Observing ferroelastic switching in Hf_(0.5)Zr_(0.5)O_(2) thin film

Hafnium zirconium oxides(HZO),which exhibit ferroelectric properties,are promising materials for nanoscale device fabrication due to their high complementary metal-oxide-semiconductor(CMOS) compatibility.In addition to piezoelectricity,ferroelectricity,and flexoelectricity,this study reports the observation of ferroelasticity using piezoelectric force microscopy(PFM) and scanning transmission electron microscopy(STEM).The dynamics of 90° ferroelastic domains in HZO thin films are investigated under the influence of an electric field.Switching of the retentive domains is observed through repeated wake-up measurements.This study presents a possibility of enhancing polarization in HZO thin films during wake-up processes.

Harmful algal bloom-forming dinofl agellate Prorocentrum donghaiense inhibits the growth and photosynthesis of seaweed Sargassum fusiformis embryos

Harmful algal bloom(HAB)is an ecological disaster to local mariculture.At present,its impact on macrophytes has not been well studied.In this study,we cultivated sexually propagated embryos of S argassum fusiformis-an edible seaweed-in Prorocentrum donghaiense suspensions at different cell densities(0,0.50×10^(5),0.75×10^(5),1.00×10^(5),and 1.50×10^(5) cells/mL)for 10 days,during which growth and photosynthetic activities of the embryos were determined,and a monocultivation was set up for comparison.Results show that the relative growth rate and photosynthetic activities of the embryos co-cultivated with P.donghaiense were inhibited mostly and significantly in the cell densities of 0.75×10^(5),1.00×10^(5),and 1.50×10^(5) cells/mL,and the inhibitory effects increased in overall with increased cell densities.The maximum relative electron transport rates(rETR max)and apparent photosynthetic efficiency(a)of co-cultivated embryos were all significantly lower than monocultivation ones on the 10 th day.Furthermore,the photosynthetic activity detected by chlorophyll-a fluorescence transient(i.e.,OJIP),the electron transport among electron transfer accepters of PSII(photosystem II)and that from PSII to PSI(photosystem I)was restricted,which is probably responsible for the decreases of rETR max andain the co-cultivated embryos.In addition,parts of the photosynthetic reaction centers of PSII in the co-cultivated embryos were inactivated.Therefore,P.donghaiense bloom could restrain the development and photosynthetic activities of S.fusiformis embryos,reduce the seedlings stock,and eventually hinder the development of S.fusiformis production industry.

Tidal water exchanges can shape the phytoplankton community structure and reduce the risk of harmful cyanobacterial blooms in a semi-closed lake

For estuaries,inland lakes play a vital role in the ecological balance under the impact of tide s.The effect of tides-induced water exchange on phytoplankton community in a semi-closed lake was studied and compared with that of an adjacent closed lake in the Oujiang River mouth in Zhejiang,East China Sea,from June 29,2020 to June 14,2021.Results show that the dominant species,abundance,dominance,and diversity of the phytoplankton species between the two lakes were significantly different.In the closed lake,cyanobacteria were the dominant species during the study period.However.in the semi-closed lake,the diversification of the dominant species was greater,and some species of diatoms and green algae became dominant.The average phytoplankton abundance in the closed lake was 6 times of that in the semi-closed lake.The average dominance of cyanobacteria in the closed lake was 0.96,and those in the semi-closed lake and the Oujiang River were 0.51 and 0.22,respectively.Cyanobacterial blooms occurred throughout the study time in the closed lake but not in the semi-closed one.Furthermore,the species diversity richness of the phytoplankton in the semi-closed lake was higher than that of the closed one,and the phytoplankton community between the closed lake and semi-closed lake could be divided into distinctly different groups based on non-metic multidimensional scaling analysis(NMDS)and analysis of similarities(ANOSIM)analysis.The salinity of the water was significantly greater and the transparency significantly smaller in the semi-closed lake than those in the closed lake.Therefore,water exchange driven by local tidal movement increased salinity and decreased transparency of water,which consequently shaped the community structures of different phytoplankton and reduced the risk of a cyanobacterial bloom outbreak in the semi-closed lake.

Adjusting the local solvation structures and hydrogen bonding networks for stable aqueous batteries with reduced cost

Exploring low-cost and effective approaches to extend the potentials of aqueous electrolytes is highly desired.Herein,it is found that the activity of H_(2)O in aqueous electrolytes could be intensively manipulated by introducing small urea and long-chain polyethylene glycol(PEG)molecules into Li TFSI-H_(2)O electrolyte systems without super salt concentration.The urea and PEG molecules could exclude partial coordinated H_(2)O out of the inner solvation shell of Li_(4) and reconstruct hydrogen-bonding network between H_(2)O and PEG molecules outside the solvation sheaths with restricted H_(2)O activity and extended electrochemical window.The bonding competitions in aqueous electrolytes and their correlation to the electrochemical performance of full cells are studied.When the occurrence probability of H_(2)O around Li_(4)is lower than 40%,stable cycling of 3.1 V LiMn_(2)O_(4)-Li_(4)Ti_(5)O_(12) full cell is achieved,showing 73%capacity retention after 200 cycles at 1 C rate in optimal electrolytes.This work provides new avenues to understand the role of H_(2)O and explore low-cost and effective approaches for the development of nextgeneration aqueous lithium-ion batteries.

Highly Aligned Ultra-Thick Gel-Based Cathodes Unlocking Ultra-High Energy Density Batteries

Increasing electrode thickness can substantially enhance the specific energy of lithium-ion batteries;however,ionic transport,electronic conductivity,and ink rheology are current barriers to adoption.Here,a novel approach using a mixed xanthan gum and locust bean gum binder to construct ultrathick electrodes is proposed to address above issues.After combining aqueous binder with single-walled carbon nanotubes(SWCNT),active material(LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)) and subsequent vacuum freeze-drying,highly aligned,and low-tortuosity structures with a porosity of ca.50%can be achieved with an average pore size of 10μm,whereby the gum binder-SWCNT-NMC811 forms vertical structures supported by tissue-like binder/SWCNT networks allowing for excellent electronic conducting phase percolation.As a result,ultra-thick electrodes with a mass loading of about 511 mg cm^(−2) and 99.5 wt%active materials have been demonstrated with a remarkable areal capacity of 79.3 mAh cm^(−2),which is the highest value reported so far.This represents a>25×improvement compared with conventional electrodes with an areal capacity of about 3 mAh cm^(−2).This route also can be expanded to other electrode materials,such as LiFePO_(4) and Li_(4)Ti_(5)O_(12),and thus opens the possibility for low-cost and sustainable ultra-thick electrodes with increased specific energy for future lithium-ion batteries.

Oxidative stress responses to cadmium in the seedlings of a commercial seaweed Sargassum fusiforme

Cadmium(Cd)is a common heavy metal pollutant in the aquatic environment,generally toxic to plant growth and leading to growth inhibition and biomass reduction.To study the oxidation resistance in Sargassum fusiforme seedlings in response to inorganic Cd stress,we cultured the seedlings under two different Cd levels:natural seawater and high Cd stress.High Cd stress significantly inhibited the seedlings growth,and darkened the thalli color.Additionally,the pigment contents,growth rate,peroxidase(POD)activity,dehydroascorbic acid(DHA)content,and glutathione reductase(GR)activity in S.fusiforme were significantly reduced by high Cd treatment.Contrarily,the Cd accumulation,Cd2+absorption rate,dark respiration/net photosynthetic rate(Rd/Pn),ascorbic acid(Vc)content,soluble protein(SP)content,glutathione(GSH),and the activities of superoxide dismutase(SOD)and catalase(CAT)of S.fusiforme under Cd treatment significantly increased compared to the control group.The decrease of malondialdehyde(MDA)was not significant.Although S.fusiforme seedlings increased the antioxidant activities of POD,SOD,Vc,and the AsA-GSH cycle to disseminate H2O2 and maintain healthy metabolism,high Cd stress caused Cd accumulation in the stem and leaves of S.fusiforme seedlings.The excessive Cd significantly restricted photosynthesis and reduced photosynthetic pigments in the seedlings,resulting in growth inhibition and deep morphological color,especially of the stems.High levels of Cd in seawater had toxic effects on commercial S.fusiforme seedlings,and risked this edible seaweed for human food.

Current diagnostic and therapeutic strategies for COVID-19

The outbreak and spread of novel coronavirus disease 2019(COVID-19) with pandemic features, which is caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2), have greatly threatened global public health. Given the perniciousness of COVID-19 pandemic, acquiring a deeper understanding of this viral illness is critical for the development of new vaccines and therapeutic options. In this review, we introduce the systematic evolution of coronaviruses and the structural characteristics of SARS-CoV-2. We also summarize the current diagnostic tools and therapeutic strategies for COVID-19.

Cyclic arginine-glycine-aspartic acid-modified red blood cells for drug delivery:Synthesis and in vitro evaluation

Red blood cells(RBCs)are an excellent choice for cell preparation research because of their biocompatibility,high drug loading,and long half-life.In this study,doxorubicin(DOX)was encapsulated with RBCs as the carrier.The biotin-avidin system binding principle was used to modify biotinylated cyclic arginine-glycine-aspartic acid(cRGD)onto RBC surfaces for accurate targeting,high drug loading,and sustained drug release.The RBC drug delivery system(DDS)was characterized,and the concentration of surface sulfur in the energy spectrum was 6.330%.The physical and chemical properties of RBC DDS were as follows:drug content,0.857 mg/mL;particle size,3339 nm;potential value,12.5 mV;and cumulative release rate,81.35%.There was no significant change in RBC morphology for up to seven days.The results of the targeting and cytotoxicity studies of RBC DDS showed that many RBCs covered the surfaces of U251 cells,and the fluorescence intensity was higher than that of MCF-7 cells.The IC50 value of unmodified drug-loaded RBCs was 2.5 times higher than that of targeted modified drug-loaded RBCs,indicating that the targeting of cancer cells produced satisfactory inhibition.This study confirms that the RBC DDS has the characteristics of accurate targeting,high drug loading,and slow drug release,which increases its likelihood of becoming a clinical cancer treatment in the future.

Transient flameout process of boron-magnesium agglomerates during combustion in oxygen-rich atmospheres

In this study,boron–magnesium agglomerates with varying mass ratios were prepared by drying a micron-sized boron–magnesium mixed suspension,and the combustion process of these agglomerates under different oxygen-rich concentrations were investigated using a laser ignition system.The test results showed that when the mass fraction of magnesium powder in boron-magnesium agglomerates exceeded a certain threshold(between 2%and 5%),flame extinction and reignition occurred after a significant reduction in the agglomerate volume during combustion.This process is referred to as the transient flameout process,which is affected by the magnesium content of the agglomerate and the oxygen concentration in the ambient atmosphere.An increase in the magnesium content or oxygen concentration makes this phenomenon more pronounced.During weakening of the flame intensity,a dark film gradually covered the particle surfaces.X-ray diffraction and elemental analyses of the cross-section and outer surface of the condensed combustion product suggested that the dark film is primarily composed of Mg-B-O ternary oxides.This film prevents direct contact between boron and oxygen,thereby inhibiting surface and gas-phase reactions and leading to the occurrence of the transient flameout phenomenon.

Preferential concentration in supersonic gas-particle two-phase transverse jets

The supersonic gas-particle two-phase transverse jet is a typical flow process in many applications,such as solid rocket scramjet.This study carried out experimental tests as well as Large Eddy Simulation(LES)to investigate the evolution process of transverse gas-particle two-phase jets in supersonic crossflow,especially focusing on the phenomena called preferential concentration.The simulation is based on the Eulerian-Lagrangian method,which successfully reproduces the characteristic phenomena observed in experiments.The particle cloud forms three different characteristic distribution patterns:tooth-like waves near the jet port,quasi-ordered structures near counter-rotating vortex pairs(CVP),and filamentous clouds in the upper part.The turbulence and small unstable shock play a suppressing role in mixing small-diameter particles,which tend to aggregate in regions of high density and low vorticity.Furthermore,it is found that there exists a specific range of particle sizes,as particles'sizes approach this specific range,the influence of compressibility of the airflow on particle distribution becomes increasingly prominent.Overall,this study shed some light on the understanding of the complex and intricate nature of the supersonic gas-particle two-phase transverse jet.

近视性屈光参差儿童青少年配戴角膜塑形镜的临床效果

目的:观察青少年近视性屈光参差配戴角膜塑形镜的临床效果。方法:回顾性自身对照研究。收集浙江大学医学院附属第二医院眼科中心从2015年12月至2017年6月之间开始配戴角膜塑形镜的患者32例,年龄8~16(11.2±2.2)岁,随访时间2年。双眼等效球镜度(SE)差值≥1.00 D,滴用睫状肌麻痹剂后的SE范围为-0.75^-6.00 D。分为高屈光度眼组(两眼中屈光度较高眼)和低屈光度眼组(两眼中屈光度较低眼),均配戴角膜塑形镜。观察双眼戴镜前以及戴镜后半年、1年、1.5年,2年的眼轴变化。数据采用配对t检验进行比较。结果:双眼眼轴差值由戴镜前的(0.46±0.24)mm下降到戴镜2年后的(0.33±0.28)mm,差异有统计学意义(t=5.038,P<0.001),高屈光度眼组戴镜2年后眼轴变化量[(0.38±0.21)mm]小于低屈光度眼组眼轴变化量[(0.51±0.26)mm],差异有统计学意义(t=6.52,P<0.001)。结论:青少年长期配戴角膜塑形镜可以减小近视性屈光参差双眼之间的眼轴差值,减少屈光参差量,可以更有效减缓近视屈光度较高眼的眼轴增长,配戴角膜塑形镜是改善屈光参差的一种有效方式。

巩膜接触镜在圆锥角膜治疗中的临床研究进展

巩膜接触镜是一种不同于传统角膜接触镜的大直径镜片,其特点是定位区在巩膜,不接触角膜,通过液体填充镜片与角膜之间的间隙,以恢复角膜的平整性。近年来,因其良好的配戴舒适性与视觉矫正功能而广泛应用于高度不规则角膜散光患者中,特别是在圆锥角膜的治疗中,已成为一项重要的治疗手段。现笔者就巩膜接触镜的设计原理及其在圆锥角膜中的治疗及临床研究进行综述。

Asymmetric interfaces and high-TC ferromagnetic phase in La_(0.67)Ca_(0.33)MnO_(3)/SrRuO_(3)superlattices

Interfacial magnetism in functional oxide heterostructures not only exhibits intriguing physical phenomena but also implies great potential for device applications.In these systems,interfacial structural and electronic reconstructions are essential for improving the stability and tunability of the magnetic properties.In this work,we constructed ultra-thinLa_(0.67)Ca_(0.33)MnO_(3)/SrRuO_(3)(SRO)layers into superlattices,which exhibited a robust ferromagnetic phase.The high Curie temperature(TC)reaches 291 K,more than 30 K higher than that of bulk LCMO.We found that the LCMO/SRO superlattices consisted of atomically-sharp and asymmetric heterointerfaces.Such a unique interface structure can trigger a sizable charge transfer as well as a ferroelectric-like polar distortion.These two interfacial effects cooperatively stabilized the high-T_(C)ferromagnetic phase.Our results could pave a promising approach towards effective control of interfacial magnetism and new designs of oxide-based spintronic devices.

Implementation for a cloud battery management system based on the CHAIN framework

An intelligent battery management system is a crucial enabler for energy storage systems with high power output,increased safety and long lifetimes.With recent developments in cloud computing and the proliferation of big data,machine learning approaches have begun to deliver invaluable insights,which drives adaptive control of battery management systems(BMS)with improved performance.In this paper,a general framework utilizing an end-edge-cloud architecture for a cloud-based BMS is proposed,with the composition and function of each link described.Cloud-based BMS leverages from the Cyber Hierarchy and Interactional Network(CHAIN)framework to provide multi-scale insights,more advanced and efficient algorithms can be used to realize the state-of-X es-timation,thermal management,cell balancing,fault diagnosis and other functions of traditional BMS system.The battery intelligent monitoring and management platform can visually present battery performance,store working-data to help in-depth understanding of the microscopic evolutionary law,and provide support for the development of control strategies.Currently,the cloud-based BMS requires more effects on the multi-scale inte-grated modeling methods and remote upgrading capability of the controller,these two aspects are very important for the precise management and online upgrade of the system.The utility of this approach is highlighted not only for automotive applications,but for any battery energy storage system,providing a holistic framework for future intelligent and connected battery management.

Effect of carbon dioxide concentration on the combustion characteristics of boron agglomerates in oxygen-containing atmospheres

In ramjet combustion chambers,carbon dioxide(CO_(2))produced by the combustion of carbonaceous fuel enters the chamber together with boron agglomerates.In order to investigate the effect of CO_(2)concentration present in an oxygen-containing atmosphere on the combustion characteristics and oxidation mechanisms of boron agglomerates,we used a laser ignition system,an X-ray diffractometer(XRD),and a thermogravimetric-differential scanning calorimetry(TG-DSC)combined thermal analysis system.Single-particle boron was tested in the laser-ignition experiments as the control group.The ignition experiment results showed that with a fixed O2 concentration of 20%,when the particle temperature reaches the melting point of boron,increasing CO_(2)content causes the combustion process of boron agglomerates to transition from single-particle molten droplet combustion to porous-particle combustion.Furthermore,XRD analysis results indicated that the condensed-phase combustion products(CCPs)of boron particles in a mixed atmosphere of O2 and CO_(2)contained B4C,which is responsible for the porous structure of the particles.At temperatures below 1200℃,the addition of CO_(2)has no obvious promotion effect on boron exothermic reaction.However,in the laser-ignition experiment,when the oxygen concentration was fixed at 20%while the CO_(2)concentration increased from 0%to 80%,the maximum temperature of boron agglomerates rose from 2434 to 2573 K,the self-sustaining combustion time of single-particle boron decreased from 396 to 169 ms,and the self-sustaining combustion time of boron agglomerates decreased from 198 to 40 ms.This study conclusively showed that adding CO_(2)to an oxygen-containing atmosphere facilitates boron reaction and consumption pathways,which is beneficial to promoting exothermic reaction of boron agglomerates at relatively high temperatures.

A preliminary observation on rod cell photobiomodulation in treating diabetic macular edema

Purpose:To evaluate the safety and effectiveness of photobiomodulation(PBM)in the treatment of diabetic macular edema(DME).Methods:It was a single-center,self-controlled prospective study.The clinical records of 12 diabetic retinopathy patients(5 males and 7 females,20 eyes in total)who were treated with PBM for DME at the Second Affiliated Hospital,Zhejiang University School of Medicine,were analyzed.The mean age was 56(26–68)years.All the participants received PBM treatment during darkness at night in no less than 5 days per week and no less than 8 h per day.In the baseline check and follow-up checks(1,2,6,10,and 12 months after the start of treatment),the best-corrected visual acuity,the thickness of the retina in the macula,and the changes of the fundus lesions were observed.Wilcoxon signed rank test was used to compare the results before and after treatment.P<0.05 was considered statistically significant.Results:No fundus complication was observed during follow-up checks.In baseline and 12-month follow-up checks,the best-corrected visual acuity was 71.75
12.47 and 79.50
10.85,maximal retinal thickness in macular area was 390.95
77.12μm and 354.13
55.03μm,average retinal thickness in macular area was 334.25
36.45μm and 314.31
33.28μm,foveal thickness was 287.00
46.79μm and 265.63
67.14μm.The best-corrected visual acuity,average retinal thickness in macular area in consecutive follow-up results except that in the 1st month showed significant difference compared with baseline results.There were significant difference between every follow-up result and baseline result of maximal retinal thickness in macular area(P<0.05).All follow-up results of foveal thickness were not significantly different(P>0.05)from the baseline result,except that in the 6th month(P?0.049).Obvious improvement could be observed in retinal fundus fluorescein angiography images.Conclusions:PBM is a safe and effective treatment of DME,which deserves further investigation.