Bandgap adjustment of a sandwich-like acoustic metamaterial plate with a frequency-displacement feedback control method

Several types of acoustic metamaterials composed of resonant units have been developed to achieve low-frequency bandgaps.In most of these structures,bandgaps are determined by their geometric configurations and material properties.This paper presents a frequency-displacement feedback control method for vibration suppression in a sandwich-like acoustic metamaterial plate.The band structure is theoretically derived using the Hamilton principle and validated by comparing the theoretical calculation results with the finite element simulation results.In this method,the feedback voltage is related to the displacement of a resonator and the excitation frequency.By applying a feedback voltage on the piezoelectric fiber-reinforced composite(PFRC)layers attached to a cantilever-mass resonator,the natural frequency of the resonator can be adjusted.It ensures that the bandgap moves in a frequency-dependent manner to keep the excitation frequency within the bandgap.Based on this frequency-displacement feedback control strategy,the bandgap of the metamaterial plate can be effectively adjusted,and the vibration of the metamaterial plate can be significantly suppressed.

Comparative coherence between layered and traditional semiconductors: unique opportunities for heterogeneous integration

As Moore’s law deteriorates,the research and development of new materials system are crucial for transitioning into the post Moore era.Traditional semiconductor materials,such as silicon,have served as the cornerstone of modern technologies for over half a century.This has been due to extensive research and engineering on new techniques to continuously enrich silicon-based materials system and,subsequently,to develop better performed silicon-based devices.Meanwhile,in the emerging post Moore era,layered semiconductor materials,such as transition metal dichalcogenides(TMDs),have garnered considerable research interest due to their unique electronic and optoelectronic properties,which hold great promise for powering the new era of next generation electronics.As a result,techniques for engineering the properties of layered semiconductors have expanded the possibilities of layered semiconductor-based devices.However,there remain significant limitations in the synthesis and engineering of layered semiconductors,impeding the utilization of layered semiconductor-based devices for mass applications.As a practical alternative,heterogeneous integration between layered and traditional semiconductors provides valuable opportunities to combine the distinctive properties of layered semiconductors with well-developed traditional semiconductors materials system.Here,we provide an overview of the comparative coherence between layered and traditional semiconductors,starting with TMDs as the representation of layered semiconductors.We highlight the meaningful opportunities presented by the heterogeneous integration of layered semiconductors with traditional semiconductors,representing an optimal strategy poised to propel the emerging semiconductor research community and chip industry towards unprecedented advancements in the coming decades.

Regulatory effect of salicylic acid and methyl jasmonate supplementation on ergosterol production in Hericium erinaceus mycelia

We evaluated the biomass and ergosterol content of Hericium erinaceus mycelium, and extracellular enzyme activities in H. erinaceus liquid culture following salicylic acid（SA） and methyl jasmonic acid（Me JA）supplementation. The optimal SA concentration was100 lmoláL-1, where the highest ergosterol content of 2.33 mgág-1was obtained following 6-day cultivation with100 lmoláL-1SA supplementation, and which was significantly higher than the unsupplemented control（p ／ 0.01）. Following 4-day supplementation with50 lmoláL-1Me JA, the highest ergosterol content obtained was 1.988 mgág-1, which was 25.8 % higher than the unsupplemented control. Our data indicate that SA and Me JA supplementation improves ergosterol content in H.erinaceus mycelium.

Operation Indices for Smart Power Dispatch Center Design

With the development of power systems, power grid within a control area becomes much more complicated due to increasing number of nodes and renewable energy interconnections. The role of power system control center is more critical in maintaining system reliable and security operations. Latest developed information and communication technologies provide a platform to enhance the functions and performance of power system control center. Smart power dispatch concept will be the trend of future control center development. In this paper, we start from the human factors of control center design and propose operation indices to reduce the information presented to the system operator. The operation indices will be the important criteria in situation awareness of a power grid. Past, present, future and capability states of a power grid are also proposed to provide better visions to the operator of system conditions. The basic ideas of operation indices and operation states are discussed in the paper. In the end, the design factors for a power dispatch cockpit are discussed.

Emerging probing perspective of two-dimensional materials physics:terahertz emission spectroscopy

Terahertz(THz)emission spectroscopy(TES)has emerged as a highly effective and versatile technique for investigating the photoelectric properties of diverse materials and nonlinear physical processes in the past few decades.Concurrently,research on two-dimensional(2D)materials has experienced substantial growth due to their atomically thin structures,exceptional mechanical and optoelectronic properties,and the potential for applications in flexible electronics,sensing,and nanoelectronics.Specifically,these materials offer advantages such as tunable bandgap,high carrier mobility,wideband optical absorption,and relatively short carrier lifetime.By applying TES to investigate the 2D materials,their interfaces and heterostructures,rich information about the interplay among photons,charges,phonons and spins can be unfolded,which provides fundamental understanding for future applications.Thus it is timely to review the nonlinear processes underlying THz emission in 2D materials including optical rectification,photon-drag,high-order harmonic generation and spin-to-charge conversion,showcasing the rich diversity of the TES employed to unravel the complex nature of these materials.Typical applications based on THz emissions,such as THz lasers,ultrafast imaging and biosensors,are also discussed.Step further,we analyzed the unique advantages of spintronic terahertz emitters and the future technological advancements in the development of new THz generation mechanisms leading to advanced THz sources characterized by wide bandwidth,high power and integration,suitable for industrial and commercial applications.The continuous advancement and integration of TES with the study of 2D materials and heterostructures promise to revolutionize research in different areas,including basic materials physics,novel optoelectronic devices,and chips for post-Moore’s era.

后摩尔时代芯片互连新材料及工艺革新

受高算力芯片的需求驱动,尽管摩尔定律日趋减缓,高端芯片的工艺复杂度和集成度仍在逐代增大.随着前道工艺中晶体管架构与其集成密度不断优化提升,后道工艺所涉及的芯片内互连技术挑战愈发严峻,迫切需要对互连材料与工艺进行革新.同时,高集成度的系统级3D封装也是高性能芯片的关键解决方案,其中核心的3D封装技术对芯片间互连材料与工艺不断提出新的要求.为此,本文系统探讨了后摩尔时代芯片内和芯片间多代候选互连材料及其工艺的潜力及挑战,从材料创新、工艺优化、架构突破、设计范式等多方面综合研判了未来互连技术的发展路径,并对超导互连、光互连等颠覆性互连技术做了前瞻性分析,可以预见互连材料的革新将有力推动新的芯片技术革命.

Design of single-phased magnesium alloys with typically high solubility rare earth elements for biomedical applications:Concept and proof

Rare earth elements(REEs)have been long applied in magnesium alloys,among which the mischmetal-containing WE43 alloy has already got the CE mark approval for clinical application.A considerable amount of REEs(7 wt%)is needed in that multi-phased alloy to achieve a good combination of mechanical strength and corrosion resistance.However,the high complex RE addition accompanied with multiple second phases may bring the concern of biological hazards.Single-phased Mg-RE alloys with simpler compositions were proposed to improve the overall performance,i.e.,“Simpler alloy,better performance”.The single-phased microstructure can be successfully obtained with typical high-solubility REEs(Ho,Er or Lu)through traditional smelting,casting and extrusion in a wide compositional range.A good corrosion resistance with a macroscopically uniform corrosion mode was guaranteed by the homogeneously single-phased microstructure.The bimodal-grained structure with plenty of sub-grain microstructures allow us to minimize the RE addition to<1 wt%,without losing mechanical properties.The single-phased Mg-RE alloys show comparable mechanical properties to the clinically-proven Mg-based implants.They exhibited similar in-vitro and in-vivo performances(without local or systematic toxicity in SD-rats)compared to a high purity magnesium.In addition,metal elements in our single-phased alloys can be gradually excreted through the urinary system and digestive system,showing no consistent accumulation of RE in main organs,i.e.,less burden on organs.The novel concept in this study focuses on the simplification of Mg-RE based alloys for biomedical purpose,and other biodegradable metals with single-phased microstructures are expected to be explored.

Recent progress on imaging technology and performance testing of PET/MR

Purpose Integrated positron emission tomography and magnetic resonance(PET/MR)is a multimodality imaging technology integrating PET and MR,which can reflect the anatomical structure and physiological function simultaneously.With the development of this technology,PET/MR plays an increasingly important role in clinical diagnosis and treatment.This review would demonstrate the current state of the latest advancement of PET/MR detection technology.Methods In this review,some studies of PET/MR detection technology in motion artifact correction,time of flight,noise reduction,performance testing methods,and phantoms were summarized.Results and conclusions PET/MR is advancing rapidly in imaging technology and has achieved phased achievements.The performance testing results of different models prove that the integration of PET and MR does not affect the respective performance,and the performance testing phantom for PET/MR needs further development.

Mechanistic Investigations into the Catalytic Mode of a Dehydratase Complex Involved in the Biosynthesis of Lantibiotic Cacaoidin

Dehydration of serine/threonine residues necessitates the activity of a dehydratase enzyme(domain)during the biosynthesis of RiPP.Recently,it was reported that dehydration in the thioviridamide pathway relies on a distinct dehydratase complex that showcases the activities of a phosphotransferase TvaC for serine/threonine phosphorylation and a lyase TvaD for subsequent phosphate elimination.Herein,we report that dehydration reactions in the pathway of lantibiotic cacaoidin involves a similar dehydratase complex,CaoK/CaoY.Remarkably,this dehydratase complex exhibits flexible enzymatic activity and tolerates significant variations in its substrate peptide sequence.By binding with the leader peptide(LP)sequence of precursor peptide CaoA,the dehydration reactions proceed in a directional manner from the C-terminus of the core peptide(CP)to the N-terminus,and C-terminally truncated variants of CP are acceptable.We show that fusing CaoK to CaoY in a 1:1 molar ratio enables the resulting enzyme CaoYK to exert enhanced dehydration activity.CaoK binds with the LP to improve its own solubility and to ensure the phosphate transfer activity,while CaoY functions in a manner independently of LP.This work advances our understanding of the dehydration process during cacaoidin formation,and provides useful enzymes and methods for the studies of the rapidly emerging RiPPs.

Reducing Social Media Attention Inequality in Disasters:The Role of Official Media During Rainstorm Disasters in China

Unequal social media attention can lead to potentially uneven distribution of disaster-relief funds,resulting in long-term inequality among regions after disasters.This study aimed to measure inequalities in social media attention to regions during disasters and explore the role of official media in reducing such inequality.This is performed by employing social media,official media,and official aggregated statistics regarding China's rainstorm disasters.Through a set of panel-data regressions and robustness tests,three main conclusions were drawn:(1)There were inequalities among regions regarding social media attention they received during rainstorm disasters.For disasters of the same magnitude,regions with low economic outcome per capita received less attention on social media.(2)Official media can reduce inequality in social media attention during disasters.Official media statements can encourage netizens to pay attention to disaster-stricken areas,and especially the overlooked underdeveloped areas.(3)Of all the measures taken by official media,timely,accurate,and open disclosure of disaster occurrences proved to be the most potent means of leveling the playing field in terms of social media attention;contrarily,promotional or booster-type messages proved futile in this regard.These findings revealed the vulnerabilities within social media landscapes that aff ect disaster relief response,shedding light on the role of official guidance in mitigating inequalities in social media attention during such crises.Our study advises social media stakeholders and policymakers on formulating more equitable crisis communication strategies to bridge the gap in social media attention and foster a more balanced and just relief process.

缓解花生连作障碍的根际促生菌分离及功能鉴定

【目的】长期连作障碍严重降低花生生产的产量及品质,根际促生菌可有效降解土壤中自毒化感物质、抑制植物病原菌生长及促进植物生长,从而有效缓解连作障碍问题。筛选优化具有缓解花生连作障碍能力的多功能根际益生微生物,验证其益生作用能力,为根际促生菌株在连作障碍中的应用提供理论依据及技术支持。【方法】采集连作12年地块花生根际土壤,利用以酚酸为唯一碳源的筛选培养基获得具有酚酸自毒化感物质降解及利用能力的根际促生菌,通过16S rRNA基因测序进行系统发育分析,确定根际促生菌菌株的分类地位,并验证其对植物病原菌生长抑制能力及解磷、解钾、产植物激素吲哚乙酸能力。【结果】从连作12年的花生发病土壤中获得7株可高效降解酚酸类自毒物质且降解底物多样的根际微生物菌株,经16S rRNA测序比对分别为克雷伯氏菌B02(Klebsiella sp.B02)、克雷伯氏菌B07(Klebsiella sp.B07)、克雷伯氏菌B15(Klebsiella sp.B15)、芽孢杆菌B28(Bacillus sp.B28)、不动杆菌P09(Acinetobacter sp.P09)、布鲁氏杆菌VA05(Brucella sp.VA05)、芽孢杆菌CA04(Bacillus sp.CA04)。促生实验表明,7株高效降解菌株均可以合成吲哚乙酸,3株具有固氮能力,4株菌具有解有机磷及无机磷的能力,2株菌具有解钾的能力。拮抗实验表明,2株菌可以抑制多种植物病原菌的生长,均为芽孢杆菌属。选取Bacillus sp.B28初步验证对花生种子萌发及幼苗生长的影响,结果表明根际促生菌可显著缓解酚酸对花生种子发芽的抑制,并明显促进花生幼苗的生长。【结论】获得多株具有降解酚酸类自毒化感物质、抑制植物病原菌生长及促进植物生长的多功能花生根际促生菌,更好地为根际促生菌在连作障碍治理中的有效应用提供菌株及技术支持。

CD44 and Hematologic Malignancies

The expression of CD44 was upregulated in some hematological malignancies and is associated with metastasis and prognosis. The ligation of CD44 with specific monoclonal antibodies can trigger terminal differentiation of leukemic blasts in some subtypes, so it is probable to develop an anti-CD44 based differentiation therapy in leukemia. The effects of CD44 and its monoclonal antibodies are discussed in this review. Cellular ＆ Molecular Immunology.

Predicting the degradation behavior of magnesium alloys with a diffusion-based theoretical model and in vitro corrosion testing

Magnesium alloys have shown great potential for their use in the medical device field, due to the promising biodegradability. However, it remains a challenge to characterize the degradation behavior of the Mg alloys in a quantitative manner. As such, controlling the degradation rate of the Mg alloys as per our needs is still hard, which greatly limits the practical application of the Mg alloys as a degradable biomaterial.This paper discussed a numerical model developed based on the diffusion theory, which can capture the experimental degradation behavior of the Mg alloys precisely. The numerical model is then implemented into a finite element scheme, where the model is calibrated with the data from our previous studies on the corrosion of the as-cast Mg-1 Ca and the as-rolled Mg-3 Ge binary alloys. The degradation behavior of a pin implant is predicted using the calibrated model to demonstrate the model’s capability. A standard flow is provided in a practical framework for obtaining the degradation behavior of any biomedical Mg alloys. This methodology was further verified via the comparison with enormous available experimental results. Lastly, the material parameters defined in this model were provided as a new kind of material property.

A comparative study on different multiple cropping patterns of Bupleurum chinense

Bupleurum chinense is a genuine medicinal material in Shanxi Province,and planting B.chinense is one of the main sources for local farmers to increase their income.In B.chinense cultivation,wheat-B.chinense,maize-B.chinense and soybean-B.chinense are commonly used as multiple cropping patterns.In the present study,we studied the effects of three different multiple cropping patterns on N,P and K levels of soil,photosynthetic parameters,agronomic characteristics,saikosaponin A,C and D contents,yield and economic benefits of B.chinense.The results showed that the soybean-B.chinense multiple cropping pattern was beneficial to the enrichment of N in the soil,thus promoting photosynthetic parameters,growth,saikosaponin accumulation,yield and economic benefits of B.chinense.It is suggested that soybean-B.chinense multiple cropping was an appropriate multiple cropping pattern for local cultivation of B.chinense.