Improving creep strength of the fine-grained heat-affected zone of novel 9Cr martensitic heat-resistant steel via modified thermo-mechanical treatment

The infamous type Ⅳ failure within the fine-grained heat-affected zone (FGHAZ) in G115 steel weldments seriously threatens the safe operation of ultra-supercritical (USC) power plants.In this work,the traditional thermo-mechanical treatment was modified via the replacement of hot-rolling with cold rolling,i.e.,normalizing,cold rolling,and tempering (NCT),which was developed to improve the creep strength of the FGHAZ in G115 steel weldments.The NCT treatment effectively promoted the dissolution of preformed M_(23)C_(6)particles and relieved the boundary segregation of C and Cr during welding thermal cycling,which accelerated the dispersed reprecipitation of M_(23)C_(6) particles within the fresh reaustenitized grains during post-weld heat treatment.In addition,the precipitation of Cu-rich phases and MX particles was promoted evidently due to the deformation-induced dislocations.As a result,the interacting actions between precipitates,dislocations,and boundaries during creep were reinforced considerably.Following this strategy,the creep rupture life of the FGHAZ in G115 steel weldments can be prolonged by 18.6%,which can further push the application of G115 steel in USC power plants.

碱性聚合物电解质膜的表面锥形阵列结构提升燃料电池性能

燃料电池作为一种清洁高效的能量转换装置,被认为是构建未来社会可再生能源结构的关键一环。不同于质子交换膜燃料电池(PEMFC),碱性聚合物电解质燃料电池(APEFC)的出现使非贵金属催化剂的使用成为可能,因而受到了日益广泛的关注和研究。APEFC的关键结构是膜电极,主要由聚合物电解质膜和阴阳极(含催化层、气体扩散层)组成,膜电极是电化学反应发生的场所,其优劣直接决定着电池性能的好坏。因此,基于现有的碱性聚合物电解质及催化剂体系,如何构筑更加优化的膜电极结构,使APEFC发挥出更高的电池性能是亟待开展的研究。本文首先通过模板法在碱性聚合物电解质膜的表面构建出有序的锥形阵列,再将具有阵列结构的一侧作为阴极来构筑膜电极,同时,作为对比,制备了由无阵列结构的聚合物电解质膜构筑而成的膜电极,最后对基于两种不同膜电极的APEFC的电化学性能进行了对比研究。实验结果表明,锥形阵列结构可以将APEFC的峰值功率密度由1.04 W·cm^(−2)显著提高到1.48 W·cm^(−2),这主要归因于在APEFC的阴极侧具有锥形阵列结构的聚合物电解质膜的亲水性的提升和催化剂电化学活性面积的增加。本工作为碱性聚合物电解质燃料电池的膜电极结构设计与优化提供了新思路。

Valley-dependent topological edge states in plasma photonic crystals

Plasma photonic crystals designed in this paper are composed of gas discharge tubes to control the flow of electromagnetic waves.The band structures calculated by the finite element method are consistent with the experimental results which have two distinct attenuation peaks in the ranges of 1-2.5 GHz and 5-6 GHz.Electromagnetic parameters of the plasma are extracted by the Nicolson-Ross-Weir method and effective medium theory.The measured electron density is between 1×1011 cm-3 and1×1012 cm-3,which verifies the correctness of the parameter used in the simulation,and the collision frequency is near 1.5×1010 Hz.As the band structures are corroborated by the measured scattering parameters,we introduce the concept of photonic topological insulator based on the quantum Valley Hall effect into the plasma photonic crystal.A valley-dependent plasma photonic crystal with hexagonal lattice is constructed,and the phase transition of the valley K(K’)occurs by breaking the spatial inversion symmetry.Valley-spin locked topological edge states are generated and excited by chiral sources.The frequency of the non-bulk state can be dynamically regulated by the electron density.This concept paves the way for novel,tunable topological edge states.More interestingly,the Dirac cone is broken when the electron density increases to 3.1×1012 cm-3,which distinguishes from the methods of applying a magnetic field and changing the symmetry of the point group.

癌症发生发展中的表观遗传学研究

癌症是由细胞恶性增殖和扩散引发的一类复杂疾病,解析其致病机制是人类目前面临的重大挑战之一。表观遗传学机制对维持基因特定的表达模式和生命个体的正常发育生长至关重要。表观遗传图谱的紊乱如组蛋白修饰、DNA/RNA甲基化和染色质三维构象的变化等均能在一定程度上干扰正常基因的表达和功能,进而诱导癌症等多种疾病的发生发展。为促进对表观遗传学在癌症中作用机制的理解,本文概述了表观遗传学研究内容,聚焦其与癌症发生发展之间的关联,同时展望了表观遗传学在癌症临床诊治中的应用。

Copper‐doped zinc sulfide nanoframes with three‐dimensional photocatalytic surfaces for enhanced solar driven H_(2) production

Solar‐to‐chemical energy conversion is perceived as one of the most potential solutions to the current energy and environmental crisis,yet requires major scientific endeavors on the development of efficient and sustainable photocatalysts.Remolding the composition and morphology of a semiconductor jointly for the purpose of improving photocatalysis efficiency remains challenging.Herein,we rationally fabricated Cu‐doped ZnS nanoframes via a simple conjunct strategy of substitutional doping,chemical acidic etching,and sulfidation,aiming at enhancing the light utilization and charge separation/transfer efficiency for solar‐light‐driven hydrogen generation.Cu‐doped zeolitic imidazolate framework‐8(ZIF‐8)rhombic dodecahedrons are transformed to hollow Cu‐ZIF‐8 nanoframes converted to Cu‐ZnS nanoframes with three‐dimensional photocatalytic active surfaces via anisotropic chemical etching,which is further converted to Cu‐ZnS nanoframes.By combining the merits of optimal heteroatom doping and frame‐like open architecture,the obtained 1%Cu‐doped ZnS nanoframe exhibits high photocatalytic activity under solar light irradiation with improved hydrogen production rate up to 8.30 mmol h^(–1) g^(–1) and excellent stability in the absence of cocatalysts,which is significantly improved in comparison with those of the bare ZnS and Cu‐ZnS with different morphologies.This work inspired by merging the merits of metal doping and anisotropic chemical etching may shed light on the rational design and fabrication of advanced photocatalysts.

Pitfalls of acid leaching method for determining organic and inorganic carbon contents in marine sediments

Organic and inorganic carbon contents of marine sediments are important to reconstruct marine productivity,global carbon cycle, and climate change. A proper method to separate and determine organic and inorganic carbons is thus of great necessity. Although the best method is still disputable, the acid leaching method is widely used in many laboratories because of its ease-of-use and high accuracy. The results of the elemental analysis of sediment trap samples reveal that organic and inorganic carbon contents cannot be obtained using the acid leaching method, causing an infinitely amplified error when the carbon content of the decarbonated sample is 12%±1% according to a mathematical derivation. Acid fumigation and gasometric methods are used for comparison, which indicates that other methods can avoid this problem in organic carbon analysis. For the first time, this study uncovers the pitfalls of the acid leaching method, which limits the implication in practical laboratory measurement, and recommends alternative solutions of organic/inorganic carbon determination in marine sediments.

SPBD:Streamlining Big-Data Processing in Cloud Environments

Many applications, such as those in genomics, are designed for one machine. This is not problematic if the input data set is small and can fit into the memory of a single powerful machine. However, the application and its algorithms are limited by the capacity and per- formance of the machine （the application cannot run in parallel）. A single machine cannot handle very large data sets. In recent research, cloud computing and MapReduce have been used together to store and process big data. There are three main steps in handling data in the cloud： 1） the user uploads the data, 2） the data is processed, and 3） results are returned. When the size of the data reaches a certain scale, transmission time becomes the dominant factor; however, most research to date has only been focused on reducing the processing time. Also, it is generally assumed that the data is already stored in the cloud. This assumption does not hoht because many organizations now store their data locally. In this paper, we propose SPBD （pronounced ＂speed ＂） to minimize overall user wait time. We abstract overall processing time as an optimization problem and derive the optimal solution. When evaluated on our private cloud platform, SPBD is shown to reduce user wait time by up to 34% for a traditional WordCount application and up to 31% for a metagenomic application.

Heating of multi-species upflowing ion beams observed by Cluster on March 28, 2001

Cluster satellites observed three successive outflowing ion beams on 28 March, 2001. It is generally accepted that these ion beams, composed of H^+, He^+, and O^+ ions, with three inverted-V structures in their energy spectra, are produced by acceleration through U-shaped potential structures. By eliminating the background ion population and employing Maxwelling fitting, we find that ions coming from the center of the potential structure have higher temperature than those from the flanks. Higher temperature of O^+ and He+compared to that of H^+ indicates that heavy ions are preferentially heated; we further infer that the heating efficiencies of O^+ and He^+ ions differ between the center and edges of the U-shaped potential structures. Estimation based on pitch angle observations shows that heating may also occur at an altitude above the upper boundary of the auroral acceleration region(AAR), where these beams are generally thought to be formed.

<i>N</i>-Order Fixed Point Theory for N-Order Generalized Meir-Keeler Type Contraction in Partially Ordered Metric Spaces

This paper concerns N-order fixed point theory in partially ordered metric spaces. For the sake of simplicity, we start our investigations with the tripled case. We define tripled generalized Meir-Keeler type contraction which extends the definition of [Bessem Samet, Coupled fixed point theorems for a generalized Meir-Keeler contraction in partially ordered metric spaces, Nonlinear Anal. 72 (2010), 4508-4517]. We then discuss the existence and uniqueness of tripled fixed point theorems in partially ordered metric spaces. For general cases, we generalized our results to the N-order case. The results will promote the study of N-order fixed point theory.

Observations of the solar corona during the total solar eclipse on 21 August 2017

The Sun’s tenuous outer atmosphere,the corona,emits only about one-millionth as much light as the solar surface.In ancient times the corona was observed by human beings only during total solar eclipses,when the strong emission of visible light from the photosphere was completely blocked by the Moon.In 1931,

A New Global Asymptotic Stability Result of Delayed Neural Networks via Nonsmooth Analysis

In the paper, we obtain new sufficient conditions ensuring existence, uniqueness, and asymptotic stability of the equilibrium point for delayed neural network via nonsmooth analysis, which makes use of the Lipschitz property of the functions. Based on this tool of nonsmooth analysis, we first obtain a couple of general results concerning the existence and uniqueness of the equilibrium point. Then we drive some new sufficient conditions ensuring global asymptotic stability of the equilibrium point. Finally, there are the illustrative examples feasibility and effectiveness of our results. Throughout our paper, the activation function is a more general function which has a wide application.

Development of Chinese herbal medicine for sensorineural hearing loss

According to the World Health Organization’s world report on hearing,nearly 2.5 billion people worldwide will suffer from hearing loss by 2050,which may contribute to a severe impact on individual life quality and national economies.Sensorineural hearing loss(SNHL)occurs commonly as a result of noise exposure,aging,and ototoxic drugs,and is pathologically characterized by the impairment of mechanosensory hair cells of the inner ear,which is mainly triggered by reactive oxygen species accumulation,inflammation,and mitochondrial dysfunction.Though recent advances have been made in understanding the ability of cochlear repair and regeneration,there are still no effective therapeutic drugs for SNHL.Chinese herbal medicine which is widely distributed and easily accessible in China has demonstrated a unique curative effect against SNHL with higher safety and lower cost compared with Western medicine.Herein we present trends in research for Chinese herbal medicine for the treatment of SNHL,and elucidate their molecular mechanisms of action,to pave the way for further research and development of novel effective drugs in this field.

Restoring cellular calcium homeostasis to rescue ER stress by 1,2-bis(2-aminophenoxy)ethane-N,N,N’,N’-tetraacetic acid acetoxymethyl ester-loaded lipid-mPLGA hybrid-nanoparticles for acute kidney injury therapy

Early pathogenesis of ischemia-reperfusion(I/R)-induced acute kidney injury(AKI)is dominated by intracellular calcium overload,which induces oxidative stress,intracellular energy metabolism disorder,inflammatory activation,and a series of pathologic cascaded reactions that are closely intertwined with self-amplifying and interactive feedback loops,ultimately resulting in cell damage and kidney failure.Currently,most nanomedicines originate from the perspective of antioxidant stress,which can only quench existing reactive oxide species(ROS)but cannot prevent the continuous production of ROS,resulting in insufficient efficacy.As a safe and promising drug,BAPTA-AM is hydrolyzed into BAPTA by intracellular esterase upon entering cells,which can rapidly chelate with overloaded Ca^(2+),restoring intracellular calcium homeostasis,thus inhibiting ROS regeneration at the source.Here,we designed a KTP-targeting peptide-modified yolk-shell structure of liposome–poly(ethylene glycol)methyl ether-block-poly(L-lactide-co-glycolic)(mPLGA)hybrid nanoparticles(<100 nm),with the characteristics of high encapsulation rate,high colloid stability,facile modification,and prolonged blood circulation time.Once the BA/mPLGA@Lipo-KTP was targeted to the site of kidney injury,the cholesteryl hemisuccinate(CHEMS)in the phospholipid bilayer,as an acidic cholesterol ester,was protonated in the simulated inflammatory slightly acidic environment(pH 6.5),causing the liposomes to rupture and release the BA/mPLGA nanoparticles,which were then depolymerized by intracellular esterase.The BAPTA-AM was diffused and hydrolyzed to produce BAPTA,which can rapidly cut off the malignant loop of calcium overload/ROS generation at its source,blocking the endoplasmic reticulum(ER)apoptosis pathway(ATF4–CHOP–Bax/Bcl-2,Casp-12–Casp-3)and the inflammatory pathway(TNF-α–NF-κB–IL-6 axes),thus alleviating pathological changes in kidney tissue,thereby inhibiting the expression of renal tubular marker kidney injury molecule 1(Kim-1)(reduced by 82.9%)and also exhibiting prominent anti-apoptotic capability(TUNEL-positive ratio decreased from 40.2%to 8.3%),significantly restoring renal function.Overall,this research holds huge potential in the treatment of I/R injury-related diseases.

Development of Mixed Insulation Oil as Alternative Liquid Dielectric:A Review

Use of traditional mineral oil(MO)as a liquid insulation in transformers has spanned more than 130 years.However,MO has poor heat resistance,a low ignition point,and is a non-renewable resource,which does not meet development requirements for high-performance and environmentally friendly insulation oil.Consequently,researchers have explored alternatives such as natural ester(NE)and synthetic ester(SE)oils,as well as mixed insulation oils.Mixed insulating oil is a blend of diverse insulating oil types,with optimal performance achieved by adjusting proportions of base oils.This article summarizes the innovative achievements and development of mixed insulation oil in terms of development of mixed ratio,basic physical chemical properties,electrical properties,thermal stability,and application including operation and maintenance technology.Through these efforts,this article aims to provide recommendations for future development of mixed insulating oils to advance liquid dielectric research based on enhancement mechanisms.

Copper-based nanomaterials as peroxidase candidates for intelligent colorimetric detection and antibacterial applications

With natural polyphenol compound tannic acid(TA)as the ingredient,copper tannate(CuTA)nanolayer material was formed by self-assembly under the conditions of heating and copper ion.Copper ion and tannic acid could coordinate to form Cu-O-C structure which was similar to the Fe-N-C structure of natural heme enzymes.In addition,the obtained CuTA nanomaterial possessed excellent peroxidase-like catalytic activity and stability.Based on this excellent enzymatic activity,CuTA nanomaterials could be used for colorimetric detection of hydrogen peroxide with a smartphone and decomposition of organic dyes.Based on the structural characteristics and catalytic activity,the copper tannate nanozymes could also serve as potential antibacterial reagents to effectively inhibit the growth of gram-negative and positive bacteria in a low hydrogen peroxide level.This work may promote the exploration of novel peroxidase mimetics and broaden the applications of nanozymes.

Microstructure-ionisation potential relationship analysis for understanding the molecular ionisation difference of natural esters during the impulse discharge via DFT calculation

Understanding the impulse discharge behaviour of natural ester(NE)is crucial for its safe application in high-voltage transformers.The ionisation potential(IP)of triglycerides plays a significant role in the process of molecular ionisation during impulse discharge for NE.The correlation coefficients between molecular size,frontier orbital,electrostatic potential,polarity,and IP were analysed.And the quantitative microstructure-IP model for triglycerides were built,which revealed that IP is strongly related to the highest occupied molecular orbital(HOMO)energy EHM,as well as the average value of positive electrostatic potential V_(p)(t),the average value of negative electrostatic potential V_(p)(-),and the surface area of negative electrostatic potential S(-).The HOMO and negative electrostatic potentials of saturated triglycerides are predominantly linked to the carbonyl O atoms.Conversely,in unsaturated triglycerides,the influence of C=C double bonds on HOMO and negative electrostatic potentials is more pronounced.Therefore,the IP of unsaturated NE with C=C bonds is lower than that of saturated NE,rendering it more susceptible to ionisation under a strong electric field which is unfavourable for impulse breakdown voltage.The structure-property correlation analysis is valuable for understanding ionisation mechanism during the impulse discharge breakdown of NE at the microscopic level.

In Situ Electrochemical Transmission Electron Microscopy for Sodium-Ion Batteries

Sodium-ion batteries(SIBs)possess promising application prospects for large-scale energy storage systems due to the abundance of sodium ions as a resource and their low cost.Development of advanced SIBs requires a clear understanding of the structures and kinetic/dynamic processes occurring in the cells during the charging/discharging process.In situ transmission electron microscopy(TEM)is a powerful tool for direct visualization of the phase transitions as well as morphological and structural evolutions of the electrodes during the electrochemical reaction process.Herein,we summarize the state-of-the-art in situ TEM studies on SIBs with a specific focus on real-time observations of the electrochemical behavior of battery materials.This review emphasizes the necessity of in situ TEM to elucidate fundamental issues regarding the reaction mechanism,phase transformation,structural evolution,and performance degradation of SIBs.Finally,critical challenges and emerging opportunities for in situ TEM research about SIBs are discussed.

Mapping Multi-factor-mediated Chromatin Interactions to Assess Dysregulation of Lung Cancer-related Genes

Studies on the lung cancer genome are indispensable for developing a cure for lung cancer.Whole-genome resequencing,genome-wide association studies,and transcriptome sequencing have greatly improved our understanding of the cancer genome.However,dysregulation of longrange chromatin interactions in lung cancer remains poorly described.To better understand the three-dimensional(3D)genomic interaction features of the lung cancer genome,we used the A549 cell line as a model system and generated high-resolution chromatin interactions associated with RNA polymerase II(RNAPII),CCCTC-binding factor(CTCF),enhancer of zeste homolog 2(EZH2),and histone 3 lysine 27 trimethylation(H3K27me3)using long-read chromatin interaction analysis by paired-end tag sequencing(ChIA-PET).Analysis showed that EZH2/H3K27me3-mediated interactions further repressed target genes,either through loops or domains,and their distributions along the genome were distinct from and complementary to those associated with RNAPII.Cancer-related genes were highly enriched with chromatin interactions,and chromatin interactions specific to the A549 cell line were associated with oncogenes and tumor suppressor genes,such as additional repressive interactions on FOXO4 and promoter–promoter interactions between NF1 and RNF135.Knockout of an anchor associated with chromatin interactions reversed the dysregulation of cancer-related genes,suggesting that chromatin interactions are essential for proper expression of lung cancer-related genes.These findings demonstrate the 3D landscape and gene regulatory relationships of the lung cancer genome.

Chronic Pulmonary Artery Stenosis:Time to Think as a Disease Entity

Chronic pulmonary artery stenosis(CPAS)is characterized by a reduction or complete obstruction of the cross-sectional area of the pulmonary artery owing to various causes.The condition exhibits similar pathophysiological progress,leading to pulmonary hypertension(PH),reduced physical endurance,right heart failure,and death.Although CPAS is often regarded as a subgroup of PH,it can manifest independently for an extended duration before the onset of PH and can significantly impact patient quality of life.It may therefore be more appropriate to consider PH as pathophysiological progression of CPAS,thereby recognizing CPAS as a distinct disease entity.

中国六省份居民对营养成分表认知情况与预包装食品购买行为的关联研究

目的分析中国六省份居民营养成分表认知情况与预包装食品购买行为之间的关联。方法采用多阶段抽样方法,于2020年7月至2021年3月在我国西部地区(四川)、东部地区(广东、江苏、北京)、中部地区(河南)、东北地区(黑龙江)抽取3002名18~70岁成年人为研究对象。通过问卷调查,收集研究对象的人口学特征、营养成分表认知情况、不同类型预包装食品购买频率等信息;采用多因素二分类logistic回归模型分析营养成分表认知情况与预包装食品购买行为的关联。结果3002名研究对象年龄为(42.3±13.4)岁,其中女性占63.8%(1914名);知道、会阅读、能理解营养成分表的比例依次为66.7%、49.8%、30.7%;每周购买≥1次预包装食品占56.6%(1699名)。多因素logistic回归分析结果显示,调整相关混杂因素后,与知道但不会阅读营养成分表者相比,知道且会阅读者每周购买≥1次11类预包装食品的可能性较高(均P<0.05)。与阅读但不能理解营养成分表者相比,阅读且能理解者每周购买≥1次11类预包装食品的可能性较低(均P<0.05)。结论居民对营养成分表认知情况与预包装食品购买行为存在关联。