Cu_(64)Zr_(36)非晶合金粉末的高温氧化行为

通过气体雾化法制备Cu_(64)Zr_(36)非晶合金粉末。采用XRD、DSC、TGA、SEM和TEM等测试手段研究Cu_(64)Zr_(36)非晶合金粉末在内部因素(粉末粒径)和外部因素(氧化温度和氧化时间)影响下的高温氧化行为。分析非晶合金粉末的氧化动力学、氧化物组成、表面形貌和显微组织演变。实验结果表明,Cu_(64)Zr_(36)非晶合金粉末氧化后表面形成多层氧化物,氧化层主要成分为t-ZrO_(2)、m-ZrO_(2)、Cu_2O和CuO。氧化动力学遵循双级抛物线速率定律。氧化过程以O离子向内扩散和Cu离子向外扩散控制。热力学分析表明,随着粉末粒径的减小,氧化反应的吉布斯自由能变大,导致粒径更小的粉末氧化更为迅速且完全。

急性重症胰腺炎

急性重症胰腺炎是急性胰腺炎中最凶险的一种类型,常导致多器官功能衰竭和全身炎症反应综合征。近年来,急性重症胰腺炎发病率逐渐增加,且死亡率较高,早期的诊断和治疗对于降低急性重症胰腺炎患者的死亡风险尤为重要。本文就近年来急性重症胰腺炎诊断和治疗中的最新研究进展作一综述。

Techno-economic assessment of a chemical looping splitting system for H2 and CO Co-generation

The natural gas(NG)reforming is currently one of the low-cost methods for hydrogen production.However,the mixture of H2 and CO_(2) in the produced gas inevitably includes CO_(2) and necessitates the costly CO_(2) separation.In this work,a novel double chemical looping involving both combustion(CLC)and sorption-enhanced reforming(SE-CLR)was proposed towards the co-production of H2 and CO(CLC-SECLRHC)in two separated streams.CLC provides reactant CO_(2) and energy to feed SECLRHC,which generates hydrogen in a higher purity,as well as the calcium cycle to generate CO in a higher purity.Techno-economic assessment of the proposed system was conducted to evaluate its efficiency and economic competitiveness.Studies revealed that the optimal molar ratios of oxygen carrier(OC)/NG and steam/NG for reforming were recommended to be 1.7 and 1.0,respectively.The heat integration within CLC and SECLRHC units can be achieved by circulating hot OCs.The desired temperatures of fuel reactor(FR)and reforming reactor(RR)should be 850
C and 600
C,respectively.The heat coupling between CLC and SECLRHC units can be realized via a jacket-type reactor,and the NG split ratio for reforming and combustion was 0.53:0.47.Under the optimal conditions,the H2 purity,the H2 yield and the CH4 conversion efficiency were 98.76%,2.31 mol mol-1 and 97.96%,respectively.The carbon and hydrogen utilization efficiency respectively were 58.60% and 72.45%in terms of the total hydrogen in both steam and NG.The exergy efficiency of the overall process reached 70.28%.In terms of the conventional plant capacity(75 × 103 t y^(-1))and current raw materials price(2500$t^(-1)),the payback period can be 6.2 years and the IRR would be 11.5,demonstrating an economically feasible and risk resistant capability.

液力推力器花键联接结构优化设计

液力推力器具有水力柔性加压的特点,广泛应用于钻压不易施加的水平井、大位移延伸井等。液力推力器在工作时,关键部件花键联接结构的磨损较为严重,失效率高。针对该问题,笔者充分考虑芯轴所受轴向压力、径向压力、扭矩和位移载荷等多种因素作用,建立了花键联接结构瞬态接触的有限元模型。借助正交试验法设计实验方案,开展了花键联接结构的齿数、齿根圆角和内圆直径3个关键结构参数对其性能的敏感性分析。最后建立花键联接结构参数优化的数学模型,并采用SQR算法对数学模型进行优化。结果表明,优化模型相比初始模型有效降低了响应量数值,其综合指标值降低约24.9%。该研究为液力推力器的设计提供了理论依据。

Construction of a high-density genetic linkage map and identification of flowering-related QTL in erect milkvetch(Astragalus adsurgens)

Erect milkvetch(Astragalus adsurgens)is a perennial legume forage crop with economic and ecological value in livestock grazing and soil-erosion control in arid and semiarid areas worldwide.Genomic information and molecular tools to support breeding and research in the species are limited.The objectives of this investigation were to map its genome using DNA markers and to identify quantitative trait loci(QTL)in the species.An F1 mapping population of 250 plants was developed from a cross between two parents with differing flowering-related traits.A high-density genetic linkage map containing 4821 markers on eight linkage groups(LGs)with a total genetic length of 1395 cM and a mean interval of 0.29 cM between adjacent markers was constructed with SLAF-seq technology.Comparative genomic analyses revealed the highest genome sequence similarity(8.71%)between erect milkvetch and Medicago truncatula,followed by Glycine max(7.65%),Cicer arietinum(7.53%),and Lupinus angustifolius(5.21%).A total of 64 significant QTL for flowering-related traits on six LGs were detected,accounting for 9.38 to 19.1%of the associated phenotype variation.Five and 48 key candidate genes for floret number and inflorescence length were identified based on the Glycyrrhiza uralensis genome.These candidate genes were involved in ubiquitination/degradation,pollen development,cell division,cytokinin biosynthetic process,and plant flowering.These findings shed light on the regulation of flowering traits in erect milkvetch and provide genomic resources for future molecular breeding of the crop.

Preparation of tungsten-particle-reinforced Zr-based bulk metallic glass composites by two-step spark plasma sintering:microstructure evolution,densification mechanism and mechanical properties

A new two-step spark plasma sintering(TSS)process with low-temperature pre-sintering and high-temperature final sintering has been successfully applied to prepare the tungsten-particle(Wp)-reinforced bulk metallic glass composites(Wp/BMGCs).Compared to normal spark plasma sintering(NS),the densification rate and relative density of Wp/BMGCs can be improved by selecting TSS with appropriate sintering pressure in the low temperature pre-sintering stage.However,the compressive strength and plastic strain of 30%Wp/BMGCs prepared by TSS are both higher than those of the samples prepared by NS.The TSS process can significantly enhance the compressive strength of 30%Wp/BMGCs by 12%and remarkably increase the plastic strain by 50%,while the trend is completely opposite for 50%Wp/BMGCs.Quasi-in situ experiments and finite element simulations reveal that uneven temperature distribution among particles during low-temperature pre-sintering causes local overheating at contact points between particles,accelerating formation of sintering neck between particles and plastic deformation of Wp.When the volume fraction of Wp is low,TSS can improve the interface bonding between particles by increasing the number of sintering necks.This makes the fracture mode of Wp/BMGCs being predominantly transgranular fracture.However,as the volume fraction of Wp increases,the adverse effects of Wp plastic deformation are becoming more and more prominent.The aggregated Wp tends to form a solid"cage structure"that hinders the bonding between particles at the interface;correspondingly,the fracture behavior of Wp/BMGCs is mainly dominated by intergranular fracture.Additionally,reducing the sintering pressure during the low-temperature pre-sintering stage of TSS has been shown to effectively decrease plastic deformation in Wp,resulting in a higher degree of densification and better mechanical properties.

Chloroplast immunity: A cornerstone of plant defense

Increasing evidence supports the notion that pattern-recognition-receptor-mediated immunity goes beyond plasma membrane-to-nucleus signaling.With the findings of the pathways linking plasma membrane and chloroplasts and the functions of stromules and perinuclear chloroplast clustering(PCC)in plant defense,chloroplast immunity has emerged as a cornerstone of plant defense and a target of plant pathogens.

SUMOylation-modified Pelota-Hbs1 RNA surveillance complex restricts the infection of potyvirids in plants

RNA quality control nonsense-mediated decay is involved in viral restriction in both plants and animals.However,it is not known whether two other RNA quality control pathways,nonstop decay and no-go decay,are capable of restricting viruses in plants.Here,we show that the evolutionarily conserved Pelota–Hbs1 complex negatively regulates infection of plant viruses in the family Potyviridae(termed potyvirids),the largest group of plant RNA viruses that accounts for more than half of the viral crop damage worldwide.Pelota enables the recognition of the functional G1-2A6-7 motif in the P3 cistron,which is conserved in almost all potyvirids.This allows Pelota to target the virus and act as a viral restriction factor.Furthermore,Pelota interacts with the SUMO E2-conjugating enzyme SCE1 and is SUMOylated in planta.Blocking Pelota SUMOylation disrupts the ability to recruit Hbs1 and inhibits viral RNA degradation.These findings reveal the functional importance of Pelota SUMOylation during the infection of potyvirids in plants.

Plant and animal positive-sense single-stranded RNA viruses encode small proteins important for viral infection in their negative-sense strand

Positive-sense single-stranded RNA(+ssRNA)viruses,the most abundant viruses of eukaryotes in nature,require the synthesis of negative-sense RNA(-RNA)using their genomic(positive-sense)RNA(+RNA)as a template for replication.Based on current evidence,viral proteins are translated via viral+RNAs,whereas-RNA is considered to be a viral replication intermediate without coding capacity.Here,we report that plant and animal+ssRNA viruses contain small open reading frames(ORFs)in their-RNA(reverse ORFs[rORFs]).Using turnip mosaic virus(TuMV)as a model for plant+ssRNA viruses,we demonstrate that small proteins encoded by rORFs display specific subcellularlocalizations,and confirm the presence of rORF2 in infected cells through mass spectrometry analysis.The protein encoded by TuMV rORF2 forms punctuate granules that are localized in the perinuclear region and co-localized with viral replication complexes.The rORF2 protein can directly interact with the viral RNA-dependent RNA polymerase,and mutation of rORF2 completely abolishes virus infection,whereas ectopic expression of rORF2 rescues the mutant virus.Furthermore,we show that several rORFs in the-RNA of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)have the ability to suppress type l interferon production and facilitate the infection of ve-sicular stomatitis virus.In addition,we provide evidence that TuMV might utilize internal ribosome entry sites to translate these small rORFs.Taken together,these findings indicate that the-RNA of+ssRNA vi-ruses can also have the coding capacity and that small proteins encoded therein play critical roles in viral infection,revealing a viral proteome larger than previously thought.

Systematic analysis of distinct flow characteristics and underlying microstructural evolution mechanisms of a novel fine-grained P/M nickel-based superalloy during isothermal compression

Isothermal forging(IF)is an effective method for forming difficult-to-deform materials like P/M superalloys.Understanding the isothermal compression microstructural evolution mechanism of a novel P/M s-peralloy provides the basis for its optimized IF planning.In this study,the isothermal compression tests of a novel fine-grained P/M nickel-based superalloy were carried out at 1000-1150℃with strain rates of 0.001-0.01 s^(−1).The results indicated that the alloy exhibits three distinct flow characteristics:continuous softening after reaching the peak stress,near-steady superplastic flow,and discontinuous hardening,corresponding to different strain rate sensitivity exponent(m)values.Varied microstructural evolution mechanisms,including grain boundary sliding(GBS),dynamic recrystallization(DRX),and grain growth,are dominated in different m-value domains.Meanwhile,different roles of primaryγ’play in microstruc-tural evolution were clarified.A moderate fraction of primaryγ’with 8.5%-14.2%can well coordinate the GBS and hinder excessive grain growth at a high m value domain(m>0.4).When 0.2<m<0.4,the role of the primaryγ’is changed to promote dislocation accumulation,accelerating the nucleation of DRXed grains.As the primaryγ’is dissolved at 1150℃,obvious grain growth was observed after compression.Work hardening effect by overgrown grains competed with DRX softening results in the discontinuous rising stress.

Recent progress in high-entropy metallic glasses

High-entropy metallic glass(HEMG)is a new type of metallic material with high-entropy alloy-like com-position and amorphous structure,which render HEMGs unusual glass formation behaviors and unique properties.In recent years,fast research progress has been witnessed on the HEMGs,and thus a sys-tematic review is required.In this review,we first introduce the concept of the HEMGs and summarize the developed HEMGs.Then,the glass-forming ability of the HEMGs is discussed,and the general rules are proposed.Focusing on the thermal stability of HEMGs,the effect of entropy on the energy states of HEMGs and the crystallization behavior of HEMGs are discussed.Finally,the mechanical,magnetic,cat-alytic and other properties of HEMGs are presented,and the advantages and disadvantages of HEMGs are shown.This review can function as a quick guideline for overviewing the HEMG field.

Zr-Ti系高熵非晶合金研究进展

高熵非晶合金是指由5种及5种以上元素(近)等原子比组成,符合无序致密堆积的结构特点,且在非晶形成过程中满足热力学、动力学及结构条件的合金.高熵非晶合金兼具高熵合金的成分特征和非晶合金的结构特征,具有优异的综合性能,有作为结构功能材料的潜力.本文以Zr-Ti系高熵非晶合金为例阐述其发展现状,首先总结高熵非晶合金的成分设计思路和晶化行为,然后介绍高熵非晶合金的力学、耐磨、耐腐蚀、热氧化、热塑性成形等性能,最后展望高熵非晶合金的发展前景与前沿研究方向.

Thermoplastic micro-formability of TiZrHfNiCuBe high entropy metallic glass

High entropy metallic glasses（MGs） have attracted tremendous attentions owing to high entropy that benefits the probing of new MG-forming systems. However, the micro-formability of high entropy MGs is lack of investigation in comparison with these conventional MG counterparts, which is crucial to the development of this kind of metallic alloys. In this work, the thermoplastic mciro-formability of TiZrHfNiCuBe high entropy MG was systemically investigated. Time-Temperature-Transformation（TTT）curve was first constructed based on isothermal crystallization experiments, which provides thermoplastic processing time of the supercooled high entropy MGs. By comparison with the deformation map,Newtonian flow was found beneficial to the thermoplastic formability. While the thermoplastic forming becomes arduous with reducing mould size to tens micrometer, because of the strong supercooled TiZrHfNiCuBe high entropy MG（fragility = 27）. Fortunately, the micro-formability of TiZrHfNiCuBe high entropy MG could be improved by vibration loading, as demonstrated by finite-element-method simulation. Our findings not only systemically evaluate the thermoplastic micro-formability of high entropy MG, but also provide fundamental understanding of the phenomenon.

The novel C5 protein from tomato yellow leaf curl virus is a virulence factor and suppressor of gene silencing

Tomato yellow leaf curl virus(TYLCV)is known to encode 6 canonical viral proteins.Our recent study revealed that TYLCV also encodes some additional small proteins with potential virulence functions.The fifth ORF of TYLCV in the complementary sense,which we name C5,is evolutionarily conserved,but little is known about its expression and function during viral infection.Here,we confirmed the expression of the TYLCV C5 by analyzing the promoter activity of its upstream sequences and by detecting the C5 protein in infected cells by using a specific custom-made antibody.Ectopic expression of C5 using a potato virus X(PVX)vector resulted in severe mosaic symptoms and higher virus accumulation levels followed by a burst of reactive oxygen species(ROS)in Nicotiana benthamiana plants.C5 was able to effectively suppress local and systemic post-transcriptional gene silencing(PTGS)induced by single-stranded GFP but not double-stranded GFP,and reversed the transcriptional gene silencing(TGS)of GFP.Furthermore,the mutation of C5 in TYLCV inhibited viral replication and the development of disease symptoms in infected plants.Transgenic overexpression of C5 could complement the virulence of a TYLCV infectious clone encoding a dysfunctional C5.Collectively,this study reveals that TYLCV C5 is a pathogenicity determinant and RNA silencing suppressor,hence expanding our knowledge of the functional repertoire of the TYLCV proteome.

Tomato yellow leaf curl virus V3 protein traffics along microfilaments to plasmodesmata to promote virus cell-to-cell movement

Dear Editor,Plant viruses spread from the initially infected cells to adjacent cells through plasmodesmata(PD) to complete their successful infections in host plants.This cell-to-cell movement requires specific viral protein(s),known as movement protein(s)(MP).Generally,virus MPs can bind to nucleic acids and modify PD size exclusion limit(Schoelz et al.,2011).Geminiviruses are DNA viruses that cause devastating losses to food crops worldwide,and encode 4–8 classical viral proteins(Gong et al.,2021;Hu et al.,2020.

Do right PLS and do PLS right: A critical review of the application of PLS-SEM in construction management research

Partial least squares structural equation modeling(PLS-SEM)is a modern multivariate analysis technique with a demonstrated ability to estimate theoretically established cause-effect relationship models.This technique has been increasingly adopted in construction management research over the last two decades.Accordingly,a critical review of studies adopting PLS-SEM appears to be a timely and valuable endeavor.This paper offers a critical review of 139 articles that applied PLS-SEM from 2002 to 2019.Results show that the misuse of PLS-SEM can be avoided.Critical issues related to the application of PLS-SEM,research design,model development,and model evaluation are discussed in detail.This paper is the first to highlight the use and misuse of PLS-SEM in the construction management area and provides recommendations to facilitate the future application of PLS-SEM in this field.

Effect of cryogenic cycling on mechanical properties of ZrTiCuNiBe bulk metallic glass

The effect of deep cryogenic cycle treatment(DCT)on Zr_(41.2)Ti_(13.8)Cu_(12.5)Ni_(10)Be_(22.5)(Vit-1)bulk metallic glass(BMG)prepared from high-purity raw materials was investigated.After DCT,no obvious rejuvenation of the samples was detected.With an increasing number of cryogenic cycles,the hardness of the samples first decreased and then increased,the room-temperature compression plasticity first increased and then generally remained unchanged,and the impact toughness underwent almost no obvious change.The absence of rejuvenation was attributed to the high fragility index(47-50)and high glass forming ability(GFA)of the material.As lower purity of the raw materials is expected in practical applications,DCT of Vit-1 BMG prepared from low-purity raw materials was also performed.After DCT,the samples prepared with the lower-purity raw materials were clearly rejuvenated,and the room-temperature mechanical properties improved significantly.Both the compression plasticity and impact toughness reached peak values after 5 cryogenic cycles.The initial impurities(including Y and O)had a complex and comprehensive effect on the deformation mechanism of the BMG during DCT.Our findings indicate that the structural heterogeneity,fragility index,and GFA of the BMG alter the effect of DCT.

A case of Landau-Kleffner syndrome with SLC26A4-related hearing impairment

Background:Landau-Kleffner syndrome(LKS)is an acquired aphasia and electroencephalogram(EEG)abnormalities mainly in temporoparietal areas.SLC26A4 mutations can cause hearing loss associated with enlarged vestibular aqueduct(EVA).Case presentations:We report a case of LKS in a 5-year-old boy with non-syndromic EVA due to homozygous mutations of c.919-2A>G(IVS7-2A>G)in SLC26A4.He had normal language development before 2 years old.At the age of 2.5 years,he was admitted to the hospital due to remarkable language delay,and diagnosed with hearing loss with EVA.The seizures started at 4.4 years of age and EEG recording showed electrical status epilepticus during sleep(ESES)with a posterior-temporal predominance.He received cochlear implantation in the right ear at 4.7 years of age,which improved his hearing and language skills.The nocturnal focal motor seizures recurred at 4.9 years of age.Then a remarkable inability to respond to calls and reduction in spontaneous speech were noticed.He was treated with methylprednisolone at 5 years old,which controlled the seizures,suppressed ESES,and remarkably improved the language ability.The absence of seizures maintained until the last follow-up at 5.3 years of age,with further improvements in EEG recording and language ability.Conclusions:The co-existence of LKS and hearing loss caused by SLC26A4 mutations increases the difficulty of LKS diagnosis,especially in the presence of hearing loss and impaired language skills.EEG discharges predominantly in temporoparietal areas,the occurrence of ESES,and language improvement after antiepileptic medications are potential indicators for LKS diagnosis.