Prognosis of radiotherapy for esophageal cancer in elderly patients exceeding seventy-five years old

BACKGROUND Esophageal cancer(EC)often occurs in the elderly,with approximately 33%of patients aged≥75 years at the time of diagnosis.AIM To evaluate the prognostic factors for radiotherapy(RT)in elderly patients with unresectable EC.METHODS We retrospectively analyzed the clinical characteristics,toxic reactions,and survival information of EC patients aged≥75 years who underwent intensity-modulated RT at Lu’an Hospital of Anhui Medical University between January 2016 and September 2023.Kaplan-Meier analysis was used to draw the overall survival(OS)curves,and Cox regression analysis was employed to evaluate the influence of various clinical factors on the prognosis.RESULTS A total of 139 patients were enrolled.The median follow-up time was 52.0 months.The median OS was 20.0 months.The 1-year,2-year,3-year,and 5-year OS rates were 69.8%,38.7%,28.2%,and 17.5%,respectively.Univariate analysis showed that age,radiation dose,and chemotherapy had no significant impact on prognosis.Multivariate analysis indicated that clinical stage[Ⅲ-Ⅳa vsⅠ-Ⅱ,hazard ratio(HR)=2.421,95%confidence interval(CI):1.242-4.718,P=0.009;IVb vsⅠ-Ⅱ,HR=4.222,95%CI:1.888-9.438,P<0.001),Charlson comorbidity index(CCI)(0 vs≥1,HR=1.539,95%CI:1.015-2.332,P=0.042),and nutritional risk screening 2002(NRS2002)(<3 vs≥3,HR=2.491,95%CI:1.601-3.875,P<0.001)were independent prognostic factors for OS.CONCLUSION Our results suggest that CCI and NRS2002 were independent prognostic factors of OS for unresectable elderly EC patients undergoing RT.For elderly patients with EC,full attention should be given to biological age-related indicators,such as comorbidities and nutrition,when formulating treatment protocols.These factors should be considered in future clinical practice.

Novel miR-490-3p/hnRNPA1-b/PKM2 axis mediates the Warburg effect and proliferation of colon cancer cells via the PI3K/AKT pathway

BACKGROUND Heterogeneous ribonucleoprotein A1(hnRNPA1)has been reported to enhance the Warburg effect and promote colon cancer(CC)cell proliferation,but the role and mechanism of the miR-490-3p/hnRNPA1-b/PKM2 axis in CC have not yet been elucidated.AIM To investigate the role and mechanism of a novel miR-490-3p/hnRNPA1-b/PKM2 axis in enhancing the Warburg effect and promoting CC cell proliferation through the PI3K/AKT pathway.METHODS Paraffin-embedded pathological sections from 220 CC patients were collected and subjected to immunohistochemical analysis to determine the expression of hnRNPA1-b.The relationship between the expression values and the clinicopathological features of the patients was investigated.Differences in mRNA expression were analyzed using quantitative real-time polymerase chain reaction,while differences in protein expression were analyzed using western blot.Cell proliferation was evaluated using the cell counting kit-8 and 5-ethynyl-2’-deoxyuridine assays,and cell cycle and apoptosis were detected using flow cytometric assays.The targeted binding of miR-490-3p to hnRNPA1-b was validated using a dual luciferase reporter assay.The Warburg effect was evaluated by glucose uptake and lactic acid production assays.RESULTS The expression of hnRNPA1-b was significantly increased in CC tissues and cells compared to normal controls(P<0.05).Immunohistochemical results demonstrated significant variations in the expression of the hnRNPA1-b antigen in different stages of CC,including stage I,II-III,and IV.Furthermore,the clinicopathologic characterization revealed a significant correlation between hnRNPA1-b expression and clinical stage as well as T classification.HnRNPA1-b was found to enhance the Warburg effect through the PI3K/AKT pathway,thereby promoting proliferation of HCT116 and SW620 cells.However,the proliferation of HCT116 and SW620 cells was inhibited when miR-490-3p targeted and bound to hnRNPA1-b,effectively blocking the Warburg effect.CONCLUSION These findings suggest that the novel miR-490-3p/hnRNPA1-b/PKM2 axis could provide a new strategy for the diagnosis and treatment of CC.

Geology and mineralization of the Daheishan supergiant porphyry molybdenum deposit(1.65 Bt),Jilin,China:A review

The Daheishan supergiant porphyry molybdenum deposit(also referred to as the Daheishan deposit)is the second largest molybdenum deposit in Asia and ranks fifth among the top seven molybdenum deposits globally with total molybdenum reserves of 1.65 billion tons,an average molybdenum ore grade of 0.081%,and molybdenum resources of 1.09 million tons.The main ore body is housed in the granodiorite porphyry plutons and their surrounding inequigranular granodiorite plutons,with high-grade ores largely located in the ore-bearing granodiorite porphyries in the middle-upper part of the porphyry plutons.Specifically,it appears as an ore pipe with a large upper part and a small lower part,measuring about 1700 m in length and width,extending for about 500 m vertically,and covering an area of 2.3 km^(2).Mineralogically,the main ore body consists of molybdenite,chalcopyrite,and sphalerite horizontally from its center outward and exhibits molybdenite,azurite,and pyrite vertically from top to bottom.The primary ore minerals include pyrite and molybdenite,and the secondary ore minerals include sphalerite,chalcopyrite,tetrahedrite,and scheelite,with average grades of molybdenum,copper,sulfur,gallium,and rhenium being 0.081%,0.033%,1.67%,0.001%,and 0.0012%,respectively.The ore-forming fluids of the Daheishan deposit originated as the CO_(2)-H_(2)O-NaCl multiphase magmatic fluid system,rich in CO_(2)and bearing minor amounts of CH4,N2,and H2S,and later mixed with meteoric precipitation.In various mineralization stages,the ore-forming fluids had homogenization temperatures of>420℃‒400℃,360℃‒350℃,340℃‒230℃,220℃‒210℃,and 180℃‒160℃and salinities of>41.05%‒9.8%NaCleqv,38.16%‒4.48%NaCleqv,35.78%‒4.49%NaCleqv,7.43%NaCleqv,and 7.8%‒9.5%NaCleqv,respectively.The mineralization of the Daheishan deposit occurred at 186‒167 Ma.The granites closely related to the mineralization include granodiorites(granodiorite porphyries)and monzogranites(monzogranite porphyries),which were mineralized after magmatic evolution(189‒167 Ma).Moreover,these mineralization-related granites exhibit low initial strontium content and high initial neodymium content,indicating that these granites underwent crust-mantle mixing.The Daheishan deposit formed during the Early-Middle Jurassic,during which basaltic magma underplating induced the lower-crust melting,leading to the formation of magma chambers.After the fractional crystallization of magmas,ore-bearing fluids formed.As the temperature and pressure decreased,the ore-bearing fluids boiled drops while ascending,leading to massive unloading of metal elements.Consequently,brecciated and veinlet-disseminated ore bodies formed.

Geology and mineralization of the Duobaoshan supergiant porphyry Cu-Au-Mo-Ag deposit(2.36 Mt)in Heilongjiang Province,China:A review

The reserves of the Duobaoshan porphyry Cu-Au-Mo-Ag deposit(also referred to as the Duobaoshan porphyry Cu deposit)ranks first among the copper deposits in China and 33rd among the porphyry copper deposits in the world.It has proven resources of copper(Cu),molybdenum(Mo),gold(Au),and silver(Ag)of 2.28×10^(6)t,80×10^(3)t,73 t,and 1046 t,respectively.The major characteristics of the Duobaoshan porphyry Cu deposit are as follows.It is located in a zone sandwiched by the Siberian,North China,and paleo-Pacific plates in an island arc tectonic setting and was formed by the Paleozoic mineralization and the Mesozoic mineralization induced by superposition and transformation.The metallogenic porphyries are the Middle Hercynian granodiorite porphyries.The alterations of surrounding rocks are distributed in a ring form.With silicified porphyries at the center,the alteration zones of K-feldspar,biotite,sericite,and propylite occur from inside to outside.This deposit is composed of 215 ore bodies(including 14 major ore bodies)in four mineralized zones.Ore body No.X in the No.3 mineralized zone has the largest resource reserves,accounting for more than 78%of the total reserves of the deposit.Major ore components include Cu,Mo,Au,Ag,Se,and Ga,which have an average content of 0.46%,0.015%,0.16 g/t,1.22 g/t,0.0003%,and 0.001%-0.003%,respectively.The ore minerals of this deposit primarily include pyrite,chalcopyrite,bornite,and molybdenite,followed by magnetite,hematite,rutile,gelenite,and sphalerite.The ore-forming fluids of this deposit were magmatic water in the early metallogenic stage and then the mixture of meteoric water and magmatic water at the late metallogenic stage.The ore-forming fluids experienced three stages.The ore-forming fluids of stageⅠhad a hydrochemical type of H_(2)O-CO_(2)-Na Cl,an ore-forming temperature of 375-650℃,and ore-forming pressure of 110-160 MPa.The ore-forming fluids of stageⅡhad a hydrochemical type of H_(2)O-CO_(2)-Na Cl,an ore-forming temperature of 310-350℃,and ore-forming pressure of 58-80 MPa.The ore-forming fluids of stageⅢhad a hydrochemical type of Na Cl-H_(2)O,an ore-forming temperature of 210-290℃,and ore-forming pressure of 5-12 MPa.The CuAu-Mo-Ag mineralization mainly occurred at stagesⅠandⅡ,with the ore-forming materials having a mixed crust-mantle source.The Duobaoshan porphyry Cu deposit was formed in the initial subduction environment of the Paleo-Asian Ocean Plate during the Early Ordovician.Then,due to the closure of the Mongol-Okhotsk Ocean and the subduction and compression of the Paleo-Pacific Ocean,a composite orogenic metallogenic model of the deposit was formed.In other words,it is a porphyry-epithermal copper-gold polymetallic mineralization system of composite orogeny consisting of Paleozoic island arcs and Mesozoic orogeny and extension.

SHRIMP zircon U-Pb age, fitho- and biostratigraphic analyses of the Huaiyu Domain in South China,— Evidence for a Neoproterozoic orogen, not Late Paleozoic-Early Mesozoic collision

In the last few decades, the Late Paleozoic-Early Mesozoic tectonic evolution of South China has been quite controversial. The focus of debate is on both the age of ophiolites and the Late Paleozoic-Early Mesozoic geological and geodynamic environment. The Huaiyu Domain is located in the NE part of South China and exposes numerous significant geological features that are keys to understand the tectonics of South China. In this paper, we present some new evidence on stratigraphy, petrology and SHRIMP zircon U-Pb geochronology, and together with other geological and geochemical data available in the literature, and the following conclusions are suggested： 1） The eastern Jiangnan ophiolites belt, dated at 858±11 Ma by SHRIMP zircon U-Pb method, was generated during the Neoproterozoic, but not the Late Paleozoic; 2） The sedimentary rocks associated with these oceanic rocks do not contain radiolarians but Neoproterozoic acritarchs; 3） During Permian-Early Triassic times, the Huaiyu Domain was dominantly characterized by a shallow sea depositional environment since deep sea sediments are absent; and 4） The pre-Devonian tectonics of South China has been reworked by late polyphase tectonism through the Triassic and the Cretaceous periods. A Late Paleozoic-Early Mesozoic deep marine domain floored by oceanic crust never existed in the study area. The geochronological and structural data do not comply with a Late Paleozoic-Early Mesozoic South China Ocean.

Study on neutronics design of ordered-pebble-bed fluoride-salt- cooled high-temperature experimental reactor

This paper presents a neutronics design of a 10 MW ordered-pebble-bed fluoride-salt-cooled high-temperature experimental reactor. Through delicate layout, a core with ordered arranged pebble bed can be formed,which can keep core stability and meet the space requirements for thermal hydraulics and neutronics measurements.Overall, objectives of the core include inherent safety and sufficient excess reactivity providing 120 effective full power days for experiments. Considering the requirements above, the reactive control system is designed to consist of 16 control rods distributed in the graphite reflector. Combining the large control rods worth about 18000–20000 pcm, molten salt drain supplementary means(-6980 to -3651 pcm) and negative temperature coefficient(-6.32 to -3.80 pcm/K) feedback of the whole core, the reactor can realize sufficient shutdown margin and safety under steady state. Besides, some main physical properties, such as reactivity control, neutron spectrum and flux, power density distribution, and reactivity coefficient,have been calculated and analyzed in this study. In addition, some special problems in molten salt coolant are also considered, including ~6Li depletion and tritium production.

The first mitochondrial genome for the butterfly family Riodinidae(Abisara fylloides) and its systematic implications

The Riodinidae is one of the lepidopteran butterfly families. This study describes the complete mitochondrial genome of the butterfly species Abisara fylloides, the first mitochondrial genome of the Riodinidae family. The results show that the entire mitochondrial genome of A. fylloides is 15301 bp in length, and contains 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes and a 423 bp A＋T-rich region. The gene content, orientation and order are identical to the majority of other lepidopteran insects. Phylogenetic reconstruction was conducted using the concatenated 13 protein-coding gene （PCG） sequences of 19 available butterfly species covering all the five butterfly families （Papilionidae, Nymphalidae, Peridae, Lycaenidae and Riodinidae）. Both maximum likelihood and Bayesian inference analyses highly supported the monophyly of Lycaenidae＋Riodinidae, which was standing as the sister of Nymphalidae. In addition, we propose that the riodinids be categorized into the family Lycaenidae as a subfamilial taxon.

MoS_(2) on topological insulator Bi_(2)Te_(3) thin films:Activation of the basal plane for hydrogen reduction

2H-MoS_(2) is a well-studied and promising non-noble metal electrocatalyst for heterogeneous reactions,such as the hydrogen evolution reaction(HER).The performance is largely limited by the chemically inert basal plane,which is unfavorable for surface adsorption and reactions.Herein,we report a facile method to boost the HER activities of 2H-MoS_(2) by coupling with epitaxial Bi2Te3 topological insulator films.The as-obtained MoS_(2)/Bi2Te3/SrTiO3 catalyst exhibits prominent HER catalytic activities compared to that of pure MoS_(2) structures,with a 189 mV decrease in the overpotential required to reach a current density of 10 mA cm^(−2) and a low Tafel slope of 58 mV dec−1.Theoretical investigations suggest that the enhanced catalytic activity originates from the charge redistribution at the interface between the Bi2Te3topological insulator films and the MoS_(2) layer.The delocalized sp-derived topological surface states could denote electrons to the MoS_(2) layer and activate the basal plane for hydrogen adsorption.This study demonstrates the potential of manipulating topological surface states to design high-performance electrocatalysts.

Complete mitogenome of the Painted Jezebel,Delias hyparete Linnaeus(Lepidoptera:Pieridae)and its comparison with other butterfly species

In the present study,we report the first complete mitochondrial genome(mitogenome)of the Painted Jezebel,Delias hyparete.The mitogenome of Delias hyparete is 15186 bp in length,and has typical sets of 37 genes:13 protein-coding genes(PCGs),2 ribosomal RNAs,22 transfer RNAs and a non-coding A+T-rich region.All protein-coding genes are initiated by ATN codons,except for COI,which is tentatively designated by the CGA codon,as observed in other butterfly species.A total of 10 PCGs harbored the complete termination codon TAA or TAG,while the COI,COII and ND5 genes ended at a single T residue.All 22 tRNA genes show typical clover structures,with the exception of the tRNASer(AGN)which lacks the dihydrouridine(DHU)stem and is instead replaced by a simple loop.Thirteen intergenic spacers totaling 153 bp,and 13 overlapping regions totaling 46 bp are scattered throughout the whole genome.The 377 bp long of D.hyparete A+T-rich region is not comprised of large repetitive sequences,but harbors several features characteristic of the lepidopteran insects,including the motif ATAGA followed by an 18 bp poly-T stretch,a microsatellite-like(AT)5 element preceded by the ATTTA motif,an 10 bp polyA-like stretch(AAAAATAAAA)present immediately upstream tRNAMet.

Complete mitogenome of the Painted Jezebel, Delias hyparete Linnaeus （Lepidoptera： Pieridae） and its comparison with other butterfly species

In the present study, we report the first complete mitochondrial genome （mitogenome） of the Painted Jezebel, Delias hyparete. The mitogenome ofDelias hyparete is 15 186 bp in length, and has typical sets of 37 genes： 13 protein-coding genes （PCGs）, 2 ribosomal RNAs, 22 transfer RNAs and a non-coding A＋T-rich region. All protein-coding genes are initiated by ATN codons, except for C01, which is tentatively designated by the CGA codon, as observed in other butterfly species. A total of 10 PCGs harbored the complete termination codon TAA or TAG; while the C01, C011and ND5 genes ended at a single T residue. All 22 tRNA genes show typical clover structures, with the exception of the tRNAser（AGn） which lacks the dihydrouridine （DHU） stem and is instead replaced by a simple loop. Thirteen intergenic spacers totaling 153 bp, and 13 overlapping regions totaling 46 bp are scattered throughout the whole genome. The 377 bp long olD. hyparete A＋T-rich region is not comprised of large repetitive sequences, but harbors several features characteristic of the lepidopteran insects, including the motif ATAGA followed by an 18 bp poly-T stretch, a microsatellite-like （AT）s element preceded by the ATTTA motif, an 10 bp polyA-like stretch （AAAAATAAAA） present immediately upstream tRNAMet.

Analysis and Zoning on Vulnerability of the Lightning Disaster in Guizhou Province

[ Objective] The research aimed to evaluate vulnerability of the lightning disaster in Guizhou and conduct zoning. [ Method] According to data of the lightning monitoring network and statistical data of the lightning disaster in Guizhou during 2007 -2012, by combining economy and population situations in 9 cities of Guizhou, 6 indicators were used to assess vulnerability of the lightning disasterCG lightning intensity, strong CG lightning intensity, annual average occurrence frequency of the lightning disaster, GDP per capita, population intensity and casualties frequency. By constructing principal component, determining weighing and comprehensive assessment, vulnerability grade of the lightning disaster in Guizhou was divided. [ Result] Guiyang was extremely high vulnerability zone, high vulnerability zone included Zunyi, Bijie and Liupanshui, moderate vulnerabili- ty zone included Anshun, Tongren and Qianxinan, Qiannan was low vulnerability zone, and Qiandongnan was extremely low vulnerability zone. Vulnerability distribution boundary of the lightning disaster in Guizhou was along northeast to southwest, and vulnerability of the lightning disaster gradually weakened from northwest to southeast. [ Conclusion] The research provided scientific basis for preventing lightning disaster and reducing damage of the lightning disaster.

3D hierarchical oxygen-deficient AlCoNi-(oxy)hydroxides/N-doped carbon hybrids enable efficient battery-type asymmetric supercapacitor

Polynary transition-metal layered hydroxides are promising energy materials owing to their unique architecture,impressive theoretical capacities,and adjustable compositions.Regulating the dimensional morphology and active sites/redox states are the keys to electrochemical performance enhancement.Distinguish from the reported mono-metal or binary-metal configurations,a new ternary-metal AlCoNi-LTH is coanchored onto a highly graphitized porous N-doped carbon matrix to develop superior 3D hierarchical microporous functional energy hybrids AlCoNi-LTHs/NAC.The constructed hybrids possess superior structural durability,good electrical conductivity,and rich active sites due to the strong interfacial conjunction and favorable synergistic effect between the doped porous carbon and AlCoNi nanosheets.Consequently,the AlCoNi-LTHs/NAC hybrids demonstrate high conductivity,reasonable specific surface area,and superior specific capacitance,and the assembled hybrid battery-type supercapacitor reveals an ideal energy density of 72.6 Wh kg^(-1)at a power density of 625 W kg^(-1),which is superior to the reported devices.This strategy opens a platform to rationally design polynary transition-metal layered hydroxides and their hybrids for efficient supercapacitors.

The first mitochondrial genome for the butterfly family Riodinidae(Abisara fylloides)and its systematic implications

The Riodinidae is one of the lepidopteran butterfly families.This study describes the complete mitochondrial genome of the butterfly species Abisara fylloides,the first mitochondrial genome of the Riodinidae family.The results show that the entire mitochondrial genome of A.fylloides is 15301 bp in length,and contains 13 protein-coding genes,2 ribosomal RNA genes,22 transfer RNA genes and a 423 bp A+T-rich region.The gene content,orientation and order are identical to the majority of other lepidopteran insects.Phylogenetic reconstruction was conducted using the concatenated 13 protein-coding gene(PCG)sequences of 19 available butterfly species covering all the five butterfly families(Papilionidae,Nymphalidae,Peridae,Lycaenidae and Riodinidae).Both maximum likelihood and Bayesian inference analyses highly supported the monophyly of Lycaenidae+Riodinidae,which was standing as the sister of Nymphalidae.In addition,we propose that the riodinids be categorized into the family Lycaenidae as a subfamilial taxon.

＂Ancient Life and Modern Approaches＂ —Second International Palaeontological Congress （IPC2006） Beijing, China, June 17-21, 2006

The Second International Palaeontological Congress （IPC2006）, a remarkable event known in the public media as the ＂Olympic Games of Global Palaeontologists＂, was successfully held from June 17-21, 2006 at the Peking University （PKU）, Beijing, China. Approximately 800 participants from 40 different countries attended this great event, including 403 participants from outside China. The participating countries included Argentina, Austria, Australia, Belgium, Brazil, Canada, China, Czech Republic, Denmark, Egypt, Germany, Finland, France, Hungary, India, Iran, Italy, Latvia, Lithuania, Japan, Korea, Malaysia, Mongolia, the Netherlands, New Zealand, Namibia, Norway, the Philippines, Poland, Portugal, Russia, Spain, Sweden, Switzerland, Thailand, the United States of America, the United Kingdom, the United Arab Emirates, and Viet Nam.

Sunflower-Like SrCo_(2)S_(4)@f-MWCNTs Hybrid Wrapped by Engineering N-Reduced Graphene Oxide for High Performance Dye-Sensitized Solar Cells

A novel sunflower-like nanocomposite of SrCo_(2)S_(4)nanoflakes and functionalized multiwall carbon nanotubes(f-MWCNTs)entanglement enveloped in nitrogen-reduced graphene oxide(N-RGO)is prepared by a cheap process.The unique entanglement structure of the material exhibits higher specific surface area,better electrical conductivity and other properties.This helps to reduce the transfer resistance in the photoelectric process of the battery and improve the electrochemical activity,thus increasing the photoelectric conversion efficiency of the battery.The new ternary cobalt-based sulfide material can replace platinum as the counter electrode(CE)material loaded on dye-sensitized solar cells(DSSCs).DSSCs with SrCo_(2)S_(4)@f-MWCNTs@N-RGO(SCS@f-M@N-R)as CE material show excellent photoelectric conversion efficiency(PCE,8.06%),even surpassing than that of Pt CE material(7.51%).The low cost,excellent electrocatalytic performance and simple preparation method of SCS@f-M@N-R nanomaterial provide feasibility for replacing platinum material as the CE material of DSSCs,which is of great significance and persuasion.

A New Speculative Execution Algorithm Based on C4.5 Decision Tree for Hadoop

As a distributed computing platform, Hadoop provides an effective way to handle big data. In Hadoop, the completion time of job will be delayed by a straggler. Although the definitive cause of the straggler is hard to detect, speculative execution is usually used for dealing with this problem, by simply backing up those stragglers on alternative nodes. In this paper, we design a new Speculative Execution algorithm based on C4.5 Decision Tree, SECDT, for Hadoop. In SECDT, we speculate completion time of stragglers and also of backup tasks, based on a kind of decision tree method: C4.5 decision tree. After we speculate the completion time, we compare the completion time of stragglers and of the backup tasks, calculating their differential value, and selecting the straggler with the maximum differential value to start the backup task.Experiment result shows that the SECDT can predict execution time more accurately than other speculative execution methods, hence reduce the job completion time.

Fragility crossover mediated by covalent-like electronic interactions in metallic liquids

Fragility is one of the central concepts in glass and liquid sciences,as it characterizes the extent of deviation of viscosity from Arrhenius behavior and is linked to a range of glass properties.However,the intervention of crystallization often prevents the assessment of fragility in poor glass-formers,such as supercooled metallic liquids.Hence experimental data on their compositional dependence are scarce,let alone fundamentally understood.In this work,we use fast scanning calorimetry to overcome this obstacle and systematically study the fragility in a ternary La–Ni–Al system,over previously inaccessible composition space.We observe fragility dropped in a small range with the Al alloying,indicating an alloying-induced fragility crossover.We use x-ray photoelectron spectroscopy,resistance measurements,electronic structure calculations,and DFT-based deep-learning atomic simulations to investigate the cause of this fragility drop.These results show that the fragility crossover can be fundamentally ascribed to the electronic covalency associated with the unique Al–Al interactions.Our findings provide insight into the origin of fragility in metallic liquids from an electronic structure perspective and pave a new way for the design of metallic glasses.

超长聚合物基复合材料油管力学性能的有限元计算

随着新疆塔里木油田钻井深度的不断攀升,其地壳内部岩浆的化学成分更加复杂,采油油管的长度要求也不断提高,因此对油管的耐腐蚀性能和力学性能提出了越来越高的要求。传统的金属油管由于强度不足,耐腐蚀性能差而无法满足深井采油的需求。非金属聚合物基复合材料油管因具有可调节的力学性能及高的耐磨抗蚀性能而逐渐获得青睐。另外,井深的提高迫切需要超长的聚合物基复合材料油管,然而其力学性能却很难从实验上进行测量。因此采用有限元模拟计算开展油管力学性能的优化计算与预测具有十分重要意义。本文针对10,000米超长非金属聚合物基复合材料油管,采用一维线性单元技术Pipe288,开展油管力学性能的优化与计算,实现了10,000米超长非金属聚合物基复合材料油管力学性能的计算。本文首先根据多尺度协同增强复合材料油管的结构特点,建立了一维线性单元的力学模型,利用ANSYS软件,基于Pipe288单元,建立了10,000米超长非金属聚合物基复合材料油管的有限元模型,分析了油管在不同的工况下的应力、应变和变形的分布规律,探讨了油管的力学性能和可靠性的影响因素,验证了本文的模型和方法的准确性和有效性。

Impact of shadow glass transition on crystallization in metallic glass

The stability of glass against crystallization is of importance in practical applications and theoretical understanding of the nature of glass materials.Annealing has complicated influences on glass stability.It induces either delayed or early crystallization,depending on detailed protocols and specific materials.By interrogating the thermal behaviors of twelve metallic glasses(MGs),we find that enhanced stability is correlated to another process:the so-called shadow glass transition and its evolution.Delayed crystallization can be observed when the shadow glass transition is shifted to cross the temperature of crystallization.Concurrently,the shadow glass transition evolves to an enthalpy overshoot.Molecular dynamics simulations support these findings and suggest that the suppressed string-like motion,relating to the shadow glass transition and the enthalpy overshoot,is likely the origin of the postponed nucleation ordering and enhanced glass stability.

Energy conversion materials need phonons

Phonons,as bosonic particles unaffected by the Pauli exclusion principle or the Fermi level,are fundamental to understanding the physical properties of solid materials.Their interactions with electrons and the crystal lattices significantly influence transport phenomena,such as electrical conductivity,mobility,and magneto-transport processes.