MXene Hollow Spheres Supported by a C–Co Exoskeleton Grow MWCNTs for Efficient Microwave Absorption

High-performance microwave absorption(MA) materials must be studied immediately since electromagnetic pollution has become a problem that cannot be disregarded. A straightforward composite material, comprising hollow MXene spheres loaded with C–Co frameworks, was prepared to develop multiwalled carbon nanotubes(MWCNTs). A high impedance and suitable morphology were guaranteed by the C–Co exoskeleton, the attenuation ability was provided by the MWCNTs endoskeleton, and the material performance was greatly enhanced by the layered core–shell structure. When the thickness was only 2.04 mm, the effective absorption bandwidth was 5.67 GHz, and the minimum reflection loss(RLmin) was-70.70 d B. At a thickness of 1.861 mm, the sample calcined at 700 ℃ had a RLmin of-63.25 d B. All samples performed well with a reduced filler ratio of 15 wt%. This paper provides a method for making lightweight core–shell composite MA materials with magnetoelectric synergy.

漂浮式光伏关键部件耐候性研究综述

为了解决能源需求和环境保护的压力,漂浮式水面光伏被提出作为解决方案。近海海域具有广阔的空间,提供了充足的布设场所,因此海上漂浮式光伏成为研究的热点。评估光伏关键部件的耐候性对确保近海漂浮式光伏系统的可靠性和持久性至关重要。近年来已出现了一些试验性水上光伏发电项目,显示出漂浮式光伏系统在水域中的潜力。然而,近海环境的湿度、海风、盐雾等因素对光伏关键部件的性能和寿命产生不利影响,因此评估光伏关键部件的耐候性能尤为重要。目前关于水上光伏的研究内容还较为有限,但各国已开始推动该技术的研究和应用。这些研究成果有助于促进近海漂浮式光伏的可持续发展,推进清洁能源的应用和环境保护。

Wellbore-heat-transfer-model-based optimization and control for cooling downhole drilling fluid

To address the two critical issues of evaluating the necessity of implementing cooling techniques and achieving real-time temperature control of drilling fluids underground in the current drilling fluid cooling technology,we first established a temperature and pressure coupled downhole heat transfer model,which can be used in both water-based and oil-based drilling fluid.Then,fourteen factors,which could affect wellbore temperature,were analyzed.Based on the standard deviation of the downhole temperature corresponding to each influencing factor,the influence of each factor was quantified.The influencing factors that can be used to guide the drilling fluid's cooling technology were drilling fluid thermal conductivity,drilling fluid heat capacity,drilling fluid density,drill strings rotation speed,pump rate,viscosity,ROP,and injection temperature.The nondominated sorting genetic algorithm was used to optimize these six parameters,but the optimization process took 182 min.Combining these eight parameters'influence rules with the nondominated sorting genetic algorithm can reduce the optimization time to 108 s.Theoretically,the downhole temperature has been demonstrated to increase with the inlet temperature increasing linearly under quasi-steady states.Combining this law and PID,the downhole temperature can be controlled,which can reduce the energy for cooling the surface drilling fluid and can ensure the downhole temperature reaches the set value as soon as possible.

Provenance of colorless and brown volcanic glass in late Pleistocene tephra layers in the Western Philippine Sea

Tephra layers in the western Philippine Sea,characterized by abundant volcanic glass shards,may provide crucial evidence on the eruption history of volcanoes and tectonic evolution of the western Pacific.A 220-ka sediment core from the Benham Rise in the western Philippine Sea offers new insights into the provenance of four intercalated tephra layers(T1–T4,in chronological order)containing either colorless or brown glass shards.Relative to primitive mantle,all glass shards are enriched in large-ion lithophile elements,such as Rb,Cs,and Pb,and depleted in high field-strength elements,such as Th,Nb,and Ta,indicating a subduction-related origin.The colorless glass shards are characterized by high SiO_(2)(>78%)and light rare earth element(LREE)contents as well as high La/Sm ratios(>9),low FeO and MgO contents(<1%),low Sr/Y(<15)and high Ba/Th ratios(>100),pointing to a rhyolitic composition and a medium-K calc-alkaline serial affinity.In contrast,the brown glass shards are characterized by lower SiO_(2)(<63%)and LREE contents,higher FeO,MgO,and CaO contents,lower La/Sm(<6)and Ba/Th(<75),and similar Sr/Y ratios(<15),indicating derivation from medium to high-K calc-alkaline andesite magma.Brown glass shards from layers T3(152 ka)and T4(172 ka)were correlated with volcanic deposits from the Taal and Laguna Caldera in the Maccolod Corridor,respectively,while the colorless glass shards from layers T1(36.5 ka)and T2(61.2 ka)were likely sourced from the Irosin Caldera in the Bicol Arc.Establishing the provenance of late Pleistocene tephra layers in the western Philippine Sea is helpful to complement a Philippine volcanic history and establish a regional tephrochronostratigraphy.

基于石墨涂层传热技术制备界面冶金结合泡沫铝夹芯板

提出一种通过石墨涂敷处理(GCT)泡沫铝夹芯板(AFS)前驱体来提高其在粉末冶金发泡过程中传热效率的新方法。研究不同传热方法的升温和膨胀特征以及对泡孔结构和抗弯性能的影响。结果表明,前驱体在采用GCT后,升温速度增加近2倍,这提高了AFS的膨胀率、改善了泡孔尺寸均匀性和外部面板形态。此外,在发泡后期阶段具有更加平稳的升温速率,这有助于提高泡孔圆度,并减少泡壁内微孔缺陷。这些改变使AFS的弯曲强度和吸能性能得以显著提高。值得注意的是,因为热传递速率不受板幅尺寸的影响,GCT技术在大尺寸AFS的生产中具有巨大潜力。

Interpenetrating network-reinforced gel polymer electrolyte for ultra-stable lithium−iodine batteries

Li-I_(2) batteries have attracted much interest due to their high capacity,exceptional rate performance,and low cost.Even so,the problems of unstable Li anode/electrolyte interface and severe polyiodide shuttle in Li-I_(2) batteries need to be tackled.Herein,the interfacial reactions on the Li anode and I_(2) cathode have been effectively optimized by employing a well-designed gel polymer electrolyte strengthened by cross-linked Ti-O/Si-O(GPETS).The interpenetrating network-reinforced GPETS with high ionic conductivity(1.88×10^(-3)S cm^(-1)at 25℃)and high mechanical strength endows uniform Li deposition/stripping over 1800 h(at 1.0mA cm^(-2),with a plating capacity of 3.0mAh cm^(-2)).Moreover,the GPETS abundant in surface hydroxyls is capable of capturing soluble polyiodides at the interface and accelerating their conversion kinetics,thus synergistically mitigating the shuttle effect.Benefiting from these properties,the use of GPETS results in a high capacity of 207 mAh g^(-1)(1 C)and an ultra-low fading rate of 0.013%per cycle over 2000 cycles(5 C).The current study provides new insights into advanced electrolytes for Li-I_(2) batteries.

Research progress of CO_(2) capture and mineralization based on natural minerals

Natural minerals,such as kaolinite,halloysite,montmorillonite,attapulgite,bentonite,sepiolite,forsterite,and wollastonite,have considerable potential for use in CO_(2) capture and mineralization due to their abundant reserves,low cost,excellent mechanical prop-erties,and chemical stability.Over the past decades,various methods,such as those involving heat,acid,alkali,organic amine,amino sil-ane,and ionic liquid,have been employed to enhance the CO_(2) capture performance of natural minerals to attain high specific surface area,a large number of pore structures,and rich active sites.Future research on CO_(2) capture by natural minerals will focus on the full utiliza-tion of the properties of natural minerals,adoption of suitable modification methods,and preparation of composite materials with high specific surface area and rich active sites.In addition,we provide a summary of the principle and technical route of direct and indirect mineralization of CO_(2) by natural minerals.This process uses minerals with high calcium and magnesium contents,such as forsterite(Mg_(2)SiO_(4)),serpentine[Mg_(3)Si_(2)O(OH)_(4)],and wollastonite(CaSiO_(3)).The research status of indirect mineralization of CO_(2) using hydro-chloric acid,acetic acid,molten salt,and ammonium salt as media is also introduced in detail.The recovery of additives and high-value-added products during the mineralization process to increase economic benefits is another focus of future research on CO_(2) mineralization by natural minerals.

Cath-KP,a novel peptide derived from frog skin,prevents oxidative stress damage in a Parkinson’s disease model

Parkinson’s disease(PD)is a neurodegenerative condition that results in dyskinesia,with oxidative stress playing a pivotal role in its progression.Antioxidant peptides may thus present therapeutic potential for PD.In this study,a novel cathelicidin peptide(Cath-KP;GCSGRFCNLF NNRRPGRLTLIHRPGGDKRTSTGLIYV)was identified from the skin of the Asiatic painted frog(Kaloula pulchra).Structural analysis using circular dichroism and homology modeling revealed a uniqueαββconformation for Cath-KP.In vitro experiments,including free radical scavenging and ferric-reducing antioxidant analyses,confirmed its antioxidant properties.Using the 1-methyl-4-phenylpyridinium ion(MPP^(+))-induced dopamine cell line and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced PD mice,Cath-KP was found to penetrate cells and reach deep brain tissues,resulting in improved MPP^(+)-induced cell viability and reduced oxidative stress-induced damage by promoting antioxidant enzyme expression and alleviating mitochondrial and intracellular reactive oxygen species accumulation through Sirtuin-1(Sirt1)/Nuclear factor erythroid 2-related factor 2(Nrf2)pathway activation.Both focal adhesion kinase(FAK)and p38 were also identified as regulatory elements.In the MPTP-induced PD mice,Cath-KP administration increased the number of tyrosine hydroxylase(TH)-positive neurons,restored TH content,and ameliorated dyskinesia.To the best of our knowledge,this study is the first to report on a cathelicidin peptide demonstrating potent antioxidant and neuroprotective properties in a PD model by targeting oxidative stress.These findings expand the known functions of cathelicidins,and hold promise for the development of therapeutic agents for PD.

Evaluating short-term and long-term liver fibrosis improvement in hepatitis C patients after DAA treatment

Despite achieving a high cure rate with the direct-acting antivirals(DAAs)in hepatitis C treatment,further research is needed to identify additional benefits of the DAA therapy.The current study evaluated liver fibrosis improvement in 848 hepatitis C patients treated with DAAs,who also achieved sustained virologic response.By the fibrosis-4(FIB-4)index,patients were categorized based on their baseline fibrosis levels,and the improvement in fibrosis was analyzed in both short-term(9-26 weeks)and long-term(≥36 weeks)follow-up.The results showed a significant decrease in the FIB-4 index,indicating an improvement in liver fibrosis,in 63.0%and 67.6%of the patients during the short-term and long-term follow-up,respectively.Short-term improvement was associated with factors including ribavirin usage,blood cholinesterase levels,alanine transaminase levels,albumin levels,and the baseline FIB-4 index,while long-term improvement was associated with factors such as aspartate transaminase levels,total protein level,and the baseline FIB-4 index.The current study emphasizes the importance of continuous assessment and post-treatment monitoring of liver fibrosis,which will provide crucial insights for enhancing patient care in hepatitis C management.

纯铜在湿热海洋大气环境空调外机内部初期腐蚀行为研究

本文采用扫描电子显微镜、电化学测试、傅里叶红外光谱等分析测试手段研究了现场实证实验空调外机内部环境中,铜暴露不同时间后的腐蚀行为和腐蚀机理。结果表明空调外机内部服役环境的严酷度明显小于外部自然大气环境。样品铜暴露7~11个月之后,铜表面致密的保护性腐蚀产物Cu_(2)O发生转变,导致样品表面腐蚀产物的保护性下降,样品的腐蚀速率呈现先下降后升高的趋势。

基于高分子参考材料透光率变化的环境应力测试装置及方法研究

不同地区的太阳辐照、气温和湿度等环境因素对产品的综合作用影响,即为综合环境应力。对于材料老化领域,综合环境应力的精准量化测量,是开展环境试验以及进行材料及产品性能设计的前提和基础。本文通过设计一种基于高分子参考材料透光率变化的环境应力测试装置,可以连续测量高分子材料透光率变化,以此量化评定环境应力。

气体辅助对PLA/TPU/GF复合材料3D打印性能的影响

熔融沉积成型(FDM)是一种应用比较广泛的快速成型工艺,但生产出的热塑性产品存在力学性能差的问题。将气体辅助挤出与FDM技术相结合,利用高温高压气体对打印件表层进行瞬间加热促进层间黏结,从而提高制件的机械强度。制备了热塑性聚氨酯(TPU)和玻璃纤维(GF)共混改性聚乳酸(PLA)3D打印材料,对比了PLA改性前后流变性能的变化。分别研究了不同气体辅助参数,如气体温度、气体流量及气体压力对FDM制件拉伸性能和冲击性能影响。结果表明:GF和TPU改性的PLA相对于纯PLA非牛顿性更强,流变性能有所提升,有助于3D打印成型。在气体辅助条件下,FDM 3D打印成型的制件强度较无气体辅助时均有所提升,最高可提升116.1%。不同气体参数对FDM制件力学性能影响规律不同,其中气体流量对制件性能影响最大。综合考虑,当气体温度、体积流量及压力分别为250℃、0.8 L/min、0.4 MPa时,制件成型性能最佳。

基于图神经网络的实体对齐表示学习方法比较研究

实体对齐是知识融合的一个重要步骤,其目的在于识别不同知识图谱中的等价实体。为准确判断出对等的实体,现有方法首先进行表示学习,将实体映射到低维向量空间中,接着通过向量间的相似度推断实体的等价性。而近期实体对齐的相关工作也大都聚焦于表示学习方法的改进上。为了能够更好地理解这些模型的机理,挖掘有价值的设计思路,并为后续的优化改进工作提供参考,对实体对齐表示学习方法进行了研究综述。首先基于现有方法,提出了一个通用的表示学习框架,并用该框架对几个具有代表性的工作进行了归纳概括以及分析解构。接着通过实验对这些工作进行了对比分析,并对框架中各个模块的常见方法进行了比较。根据实验结果,总结了各种方法的优劣,并提出了使用建议。最后初步讨论了大规模语言模型与知识图谱对齐融合的可行性,并分析了存在的问题以及潜在的挑战。

Expert Consensus on Nutritional Support for Children with Congenital Heart Disease(2023 Edition)

The second edition of the expert consensus on pediatric nutrition was formed based on a global update of pedia-tric nutrition guidelines or consensus worldwide,the management of congenital heart disease,and the results of multi-center clinical nutrition research for congenital heart disease following thefirst Chinese consensus edition of 2016.The consensus was also shaped by the results of three discussion sessions and two questionnaires con-ducted by the 13-member collaboration group.This process was informed by both clinical guidelines and expert consensus.The quality of literature,both in English and Chinese,and the level of recommendations were evaluated using the Grading of Recommendations Assessment,Development,and Evaluations(GRADE)system.

空调换热器在海洋环境条件下服役的大气腐蚀仿真

为解决海洋环境下空调换热器会发生严重腐蚀,进而影响空调换热器的性能。提出一种大气腐蚀仿真方法来分析和预测海洋环境条件以及空调换热器的工况条件对其腐蚀状况的影响。从材料参数的获取、模型的创建、边界条件的设置,介绍了空调换热器在海洋环境条件下服役的大气腐蚀仿真过程;提供了利用人工加速环境实验箱来验证仿真模型准确度的方法。通过该仿真结果可观察到空调换热器主要发生腐蚀的位置及样貌,获得相关腐蚀数据,并且可分析出影响空调换热器腐蚀的主要因素以及改善方法。

Ferroelectricity of hafnium oxide-based materials:Current status and future prospects from physical mechanisms to device applications

The finding of the robust ferroelectricity in HfO_(2)-based thin films is fantastic from the view point of both the fundamentals and the applications.In this review article,the current research status of the future prospects for the ferroelectric HfO_(2)-based thin films and devices are presented from fundamentals to applications.The related issues are discussed,which include:1)The ferroelectric characteristics observed in HfO_(2)-based films and devices associated with the factors of dopant,strain,interface,thickness,defect,fabrication condition,and more;2)physical understanding on the observed ferroelectric behaviors by the density functional theory(DFT)-based theory calculations;3)the characterizations of microscopic and macroscopic features by transmission electron microscopes-based and electrical properties-based techniques;4)modeling and simulations,5)the performance optimizations,and 6)the applications of some ferroelectric-based devices such as ferroelectric random access memory,ferroelectric-based field effect transistors,and the ferroelectric tunnel junction for the novel information processing systems.

Impairment of rigidity sensing caused by mutant TP53 gain of function in osteosarcoma

Osteosarcoma(OS)is the most common primary malignant pediatric bone tumor and is characterized by high heterogeneity.Studies have revealed a wide range of phenotypic differences among OS cell lines in terms of their in vivo tumorigenicity and in vitro colony-forming abilities.However,the underlying molecular mechanism of these discrepancies remains unclear.The potential role of mechanotransduction in tumorigenicity is of particular interest.To this end,we tested the tumorigenicity and anoikis resistance of OS cell lines both in vitro and in vivo.We utilized a sphere culture model,a soft agar assay,and soft and rigid hydrogel surface culture models to investigate the function of rigidity sensing in the tumorigenicity of OS cells.Additionally,we quantified the expression of sensor proteins,including four kinases and seven cytoskeletal proteins,in OS cell lines.The upstream core transcription factors of rigidity-sensing proteins were further investigated.We detected anoikis resistance in transformed OS cells.The mechanosensing function of transformed OS cells was also impaired,with general downregulation of rigidity-sensing components.We identified toggling between normal and transformed growth based on the expression pattern of rigidity-sensing proteins in OS cells.We further uncovered a novel TP53 mutation(R156P)in transformed OS cells,which acquired gain of function to inhibit rigidity sensing,thus sustaining transformed growth.Our findings suggest a fundamental role of rigidity-sensing components in OS tumorigenicity as mechanotransduction elements through which cells can sense their physical microenvironment.In addition,the gain of function of mutant TP53 appears to serve as an executor for such malignant programs.

基础有机化学中几类经典有机反应的改进创新

介绍了几类经典有机反应的改进创新,包括Brosted酸催化的炔烃水合反应、无氨Birch还原反应、碘仿反应合成酰胺、基于自活化循环的Beckmann重排反应、芳基重氮盐的双分子脱氮偶联反应等。这些反应与基础有机化学密切相关,并且主要是国内科研团队取得的创新成果,体现了我国学者在学科发展中所做出的重要贡献。希望对这些反应的总结能够对丰富和拓展基础有机化学的教学内容有所帮助,同时也为有机化学课程思政教育尤其是爱国主义教育提供新的素材。

分离格栅视觉诱发电位与蓝黄视野检查诊断开角型青光眼的性能比较

目的:评估分离格栅视觉诱发电位(IC-VEP)在诊断开角型青光眼中的表现,并将其与蓝黄色视野检查法(B/YP)和光学相干断层扫描(OCT)进行比较。方法:通过回顾性分析,对来自中国的101例受试者(正常组35例;早期青光眼30例,中晚期青光眼患者36例)分别进行IC-VEP、蓝黄色视野检查和OCT等检查。计算IC-VEP、视野检查法和OCT对检测青光眼的敏感度以及这三种方法之间的一致性,以评估其临床表现。结果:早期POAG组的IC-VEP、蓝黄色视野检查和OCT的敏感度分别为70.00%、70.00%、63.33%。在中晚期POAG组中,IC-VEP、OCT和蓝黄色视野检查的敏感度分别为86.11%、88.89%、91.67%。其中IC-VEP的特异性为91.43%。IC-VEP的结果与OCT和蓝黄色视野测试高度一致(kappa:0.721~1.000,P<0.05)。结论:作为视觉功能的客观检查手段,IC-VEP可用于青光眼的早期诊断,也可用于监测可疑青光眼患者的RGC功能。

Deformation response of roof in solid backfilling coal mining based on viscoelastic properties of waste gangue

Solid backfill mining(SBM)is a form of green mining,the core of which is to control and minimize the deformation and movement of strata above longwall coal mines.Establishing a mechanical model that can reliably describe roof deformation by considering the viscoelastic properties of waste gangue is important as it assists in improving mine designs and reducing the environmental impact on the surface.In this paper,the time-dependent deformation characteristics of gangue under different stress levels were obtained by using lateral confinement compression,that reliably represents the compaction of goaf.The viscoelastic foundation model for gangue mechanical response is different from the traditionally used elastic foundation model,as it considers the time factor and viscoelasticity.A mechanical model using a thin plate on a fractional viscoelastic foundation was established,and the roof deflection,bending moment,time-dependent,viscous and other characteristics of SBM were included and analyzed.Compared with the existing elastic foundation model,the proposed fractional order viscoelastic foundation model has higher accuracy with laboratory data.The plate deflection increases by 50.9%and the bending moment increases by 37.9%after 100 days,which the elastic model would not have been able to predict.