Electronic Correlation and Pseudogap-Like Behavior of High-Temperature Superconductor La_(3)Ni_(2)O_(7)

High-temperature superconductivity(HTSC)remains one of the most challenging and fascinating mysteries in condensed matter physics.Recently,superconductivity with transition temperature exceeding liquid-nitrogen temperature is discovered in La_(3)Ni_(2)O_(7) at high pressure,which provides a new platform to explore the unconventional HTSC.In this work,using high-resolution angle-resolved photoemission spectroscopy and ab initio calculation,we systematically investigate the electronic structures of La_(3)Ni_(2)O_(7) at ambient pressure.Our experiments are in nice agreement with ab initio calculations after considering an orbital-dependent band renormalization effect.The strong electron correlation effect pushes a flat band of d_(z^(2))𝑧2 orbital component below the Fermi level(E_(F)),which is predicted to locate right at E_(F) under high pressure.Moreover,the d_(x^(2)−y^(2)) band shows pseudogap-like behavior with suppressed spectral weight and diminished quasiparticle peak near E_(F).Our findings provide important insights into the electronic structure of La_(3)Ni_(2)O_(7),which will shed light on understanding of the unconventional superconductivity in nickelates.

Pressure-Tunable Large Anomalous Hall Effect in Ferromagnetic Metal LiMn_(6)Sn_(6)

Recently, giant intrinsic anomalous Hall effect(AHE) has been observed in the materials with kagome lattice.Here, we systematically investigate the influence of high pressure on the AHE in the ferromagnet LiMn_(6)Sn_(6) with clean Mn kagome lattice. Our in situ high-pressure Raman spectroscopy indicates that the crystal structure of LiMn_(6)Sn_(6) maintains a hexagonal phase under high pressures up to 8.51 GPa. The anomalous Hall conductivity(AHC) σ_(xy)^(A) remains around 150 Ω^(-1)·cm^(-1), dominated by the intrinsic mechanism. Combined with theoretical calculations, our results indicate that the stable AHE under pressure in Li Mn_(6)Sn_(6) originates from the robust electronic and magnetic structure.

SlMYB72 affects pollen development by regulating autophagy in tomato

The formation and development of pollen are among the most critical processes for reproduction and genetic diversity in the life cycle of f lowering plants.The present study found that SlMYB72 was highly expressed in the pollen and tapetum of tomato f lowers.Downregulation of SlMYB72 led to a decrease in the amounts of seeds due to abnormal pollen development compared with wild-type plants.Downregulation of SlMYB72 delayed tapetum degradation and inhibited autophagy in tomato anther.Overexpression of SlMYB72 led to abnormal pollen development and delayed tapetum degradation.Expression levels of some autophagy-related genes(ATGs)were decreased in SlMYB72 downregulated plants and increased in overexpression plants.SlMYB72 was directly bound to ACCAAC/ACCAAA motif of the SlATG7 promoter and activated its expression.Downregulation of SlATG7 inhibited the autophagy process and tapetum degradation,resulting in abnormal pollen development in tomatoes.These results indicated SlMYB72 affects the tapetum degradation and pollen development by transcriptional activation of SlATG7 and autophagy in tomato anther.The study expands the understanding of the regulation of autophagy by SlMYB72,uncovers the critical role that autophagy plays in pollen development,and provides potential candidate genes for the production of male-sterility in plants.

食管黏膜白色苔藓样病变是早期食管癌及癌前病变ESD术后切缘阳性的危险因素

目的:探讨早期食管癌及癌前病变合并白色苔藓样病变患者临床、内镜及组织病理学特征。方法:回顾性分析2017年9月至2021年8月于四川省南充市川北医学院附属医院行内镜黏膜下剥离术(endoscopic submucosal dissection,ESD)治疗且术后病理诊断为早期食管癌及癌前病变患者资料。共198例患者纳入研究,通过内镜下判断是否合并白色苔藓样病变,分为2组,分析其临床、内镜及组织病理学特征有无差异。结果:198例早期食管癌及癌前病变患者中有119例合并白色苔藓样病变,并与ESD术后切缘阳性有关(P=0.032)。ESD术后标本切缘阳性34例,进一步行多因素分析,发现合并有白色苔藓样病变(P=0.036)、病变累计管周范围(>3/4管周,P<0.001)、术后病理(黏膜内癌以下,P=0.002)、病变浸润深度(M3以下,P<0.001)是早期食管癌及癌前病变患者ESD术后切缘阳性的独立危险因素。结论:早期食管癌及癌前病变合并白色苔藓样病变患者ESD术后切缘阳性风险性增加;病变累计管周范围>3/4管周、病变浸润深度是切缘阳性的独立危险因素。

Seismic attenuation in the lower mantle beneath Northeast China constrained from short-period reflected core phases at short epicentral distances

The thermal structure of the lower mantle plays a key role in understanding the dynamic processes of the Earth's evolution and mantle convection.Because intrinsic attenuation in the lower mantle is highly sensitive to temperature,determining of the attenuation of the lower mantle could help us determine its thermal state.We attempted to constrain the attenuation of the lower mantle by measuring the amplitude ratios of p to ScP on the vertical component and s to ScS on the tangential component at short epicentral distances for seismic wave data from deep earthquakes in Northeast China.We calculated the theoretical amplitude ratios of p to ScP and s to ScS by using ray theory and the axial-symmetric spectral element method AxiSEM,as well as by considering the effects of radiation patterns,geometrical spreading,and ScP reflection coefficients.By comparing the observed amplitude ratios with the synthetic results,we constrained the quality factors as Qα≈3,000 and Qβ≈1,300 in the lower mantle beneath Northeast China,which are much larger than those in the preliminary reference Earth model(PREM)model of Qα~800 and Qβ~312.We propose that the lower mantle beneath Northeast China is relatively colder than the average mantle,resulting in weaker intrinsic attenuation and higher velocity.We estimated the temperature of the lower mantle beneath Northeast China as approximately 300–700 K colder than the global average value.

Pressure-Induced Topological and Structural Phase Transitions in an Antiferromagnetic Topological Insulator

Recently,natural van der Waals heterostructures of(MnBi2 Te4)m(Bi2 Te3)n have been theoretically predicted and experimentally shown to host tunable magnetic properties and topologically nontrivial surface states.We systematically investigate both the structural and electronic responses of MnBi2 Te4 and MnBi4 Te7 to external pressure.In addition to the suppression of antiferromagnetic order,MnBi2 Te4 is found to undergo a metalsemiconductor-metal transition upon compression.The resistivity of MnBi4 Te7 changes dramatically under high pressure and a non-monotonic evolution of p(T)is observed.The nontrivial topology is proved to persist before the structural phase transition observed in the high-pressure regime.We find that the bulk and surface states respond differently to pressure,which is consistent with the non-monotonic change of the resistivity.Interestingly,a pressure-induced amorphous state is observed in MnBi2 Te4,while two high-pressure phase transitions are revealed in MnBi4 Te7.Our combined theoretical and experimental research establishes MnBi2 Te4 and MnBi4 Te7 as highly tunable magnetic topological insulators,in which phase transitions and new ground states emerge upon compression.

Electronic structure and spatial inhomogeneity of iron-based superconductor FeS

Iron-based superconductor family FeX(X=S,Se,Te)has been one of the research foci in physics and material science due to their record-breaking superconducting temperature(FeSe film)and rich physical phenomena.Recently,FeS,the least studied Fe X compound(due to the difficulty in synthesizing high quality macroscopic crystals)attracted much attention because of its puzzling superconducting pairing symmetry.In this work,combining scanning tunneling microscopy and angle resolved photoemission spectroscopy(ARPES)with sub-micron spatial resolution,we investigate the intrinsic electronic structures of superconducting FeS from individual single crystalline domains.Unlike FeTe or FeSe,FeS remains identical tetragonal structure from room temperature down to 5 K,and the band structures observed can be well reproduced by our ab-initio calculations.Remarkably,mixed with the 1×1 tetragonal metallic phase,we also observe the coexistence of √5×√5 reconstructed insulating phase in the crystal,which not only helps explain the unusual properties of FeS,but also demonstrates the importance of using spatially resolved experimental tools in the study of this compound.

妊娠中期贫血对新生儿体格发育指标的影响分析

目的研究妊娠中期贫血对新生儿体格发育指标的影响。方法选取2019年1月—2019年10月在本院分娩的单胎无其它并发症及合并症的产妇382例作为研究对象,入院待产时回顾性收集妊娠中期血常规结果,分娩后立即测量新生儿出生体重和身长,并计算体质指数。所有数据采用SPSS软件进行统计学分析。结果贫血组孕妇所分娩新生儿的体重(2730.47±183.94 g vs 3366.78±306.98 g)、身长(48.49±1.39 cm vs 50.64±1.37 cm)以及出生孕周(38.56±1.35周vs 39.38±0.98周)均小于对照组(均P<0.05),而两组的体质指数(BMI)无统计学差异(20.99±4.64 kg/m^(2) vs 20.98±4.52 kg/m^(2),P>0.05)。贫血孕妇早产及低体重儿的发生率均高于正常孕妇(均为10.59%vs 0%,P<0.05)。妊娠中期血红蛋白水平与出生体重及身长均存在正相关(r值分别为0.331和0.377,均P<0.05)。结论妊娠中期贫血是早产和低出生体重儿的危险因素,新生儿出生体重和身长与母体血红蛋白浓度存在正相关。

Electronic structure and spin–orbit coupling in ternary transition metal chalcogenides Cu_(2)TlX_(2)(X = Se, Te)

Ternary transition metal chalcogenides provide a rich platform to search and study intriguing electronic properties. Using angle-resolved photoemission spectroscopy and ab initio calculation, we investigate the electronic structure of Cu_(2)TlX_(2)(X = Se, Te), ternary transition metal chalcogenides with quasi-two-dimensional crystal structure. The band dispersions near the Fermi level are mainly contributed by the Te/Se p orbitals. According to our ab-initio calculation, the electronic structure changes from a semiconductor with indirect band gap in Cu_(2)TlSe_(2) to a semimetal in Cu_(2)TlTe_(2), suggesting a band-gap tunability with the composition of Se and Te. By comparing ARPES experimental data with the calculated results, we identify strong modulation of the band structure by spin–orbit coupling in the compounds. Our results provide a ternary platform to study and engineer the electronic properties of transition metal chalcogenides related to large spin–orbit coupling.

Exploration of Waterproofness of Concrete and Alkali-Aggregate Using Hydrophobic Impregnation and Coating

Part of the tunnel spoil can not be used for concrete due to alkali aggregate reaction(AAR).Water is an indis-pensable condition for AAR,so separating the alkali-aggregate from water is of great benefit to controlling the AAR.This paper investigates the modification of concrete and aggregate by hydrophobic impregnation and organic coating and then evaluates their waterproof and me chanical properties by dynamic contact angle(DCA),ultrasonic wave velocity,scanning electron microscope(SEM),nuclear magnetic resonance(NMR),and so on.For waterproofness,hydrophobic impregnation and organic coating can both improve the waterproof-ness of concrete and aggregate.The organic coating is suitable for aggregate because it wrap aggregate well.And aggregate coated by PVA can improve the interfacial transition zone(ITZ).For mechanical properties,both mate-rials will weaken the strength of the interface.Furthermore,concrete made by aggregate with organic coating shows plastic deformation and has a good correlation with the film thickness,a plastic estimation model based on flm thickness is proposed.This paper evaluates the waterproof of concrete and aggregate and finds plastic con-crete with good aggregate waterproofness which provides a new idea for the application of alkali aggregate in see-page control facilities of water conservancy projects.

Measurement of electronic structure in van der Waals ferromagnet Fe_(5-x)GeTe_(2)

As a van der Waals ferromagnet with high Curie temperature,Fe_(5-x)GeTe_(2) has attracted tremendous interests recently.Here,using high-resolution angle-resolved photoemission spectroscopy(ARPES),we systematically investigated the electronic structure of Fe_(5-x)GeTe_(2) crystals and its temperature evolution.Our ARPES measurement reveals two types of band structures from two different terminations with slight kz evolution.Interestingly,across the ferromagnetic transition,we observed the merging of two split bands above the Curie temperature,suggesting the band splitting due to the exchange interaction within the itinerant Stoner model.Our results provide important insights into the electronic and magnetic properties of Fe_(5-x)GeTe_(2) and the understanding of magnetism in a two-dimensional ferromagnetic system.

Quantum Oscillations in Noncentrosymmetric Weyl Semimetal SmAlSi

As a new type of quantum state of matter hosting low energy relativistic quasiparticles,Weyl semimetals(WSMs)have attracted significant attention for scientific community and potential quantum device applications.In this study,we present a comprehensive investigation of the structural,magnetic,and transport properties of noncentrosymmetric RAl Si(R=Sm,Ce),which have been predicted to be new magnetic WSM candidates.Both samples exhibit nonsaturated magnetoresistance,with about 900%and 80%for Sm Al Si and Ce Al Si,respectively,at temperature of 1.8 K and magnetic field of 9 T.The carrier densities of Sm Al Si and Ce Al Si exhibit remarkable change around magnetic transition temperatures,signifying that the electronic states are sensitive to the magnetic ordering of rare-earth elements.At low temperatures,Sm Al Si reveals prominent Shubnikov–de Haas oscillations associated with the nontrivial Berry phase.High-pressure experiments demonstrate that the magnetic order is robust and survival under high pressure.Our results would yield valuable insights into WSM physics and potentials in applications to next-generation spintronic devices in the RAl Si(R=Sm,Ce)family.

Analysis of the False Alarm Fault in Antenna-servo System of Weather Radar

A false alarm fault frequently appeared in antenna-servo system of the CINRAD/SA weather radar of Shanwei in the second half of 2011, so possible reasons for the false alarm fault were listed firstly using method of exhaustion, and then the main reason was determined using exclusive method. That is, the fault was closely related to the signal transmission channel from the antenna mount to servo system in RDA cabinet. After ex- amining questionable nodes in the transmission channels of the alarm signal, we found that the false alarm fault might result from the interference of a burr in the temperature sensing circuit of the elevation motor. In actual operation, a filter capacitor was connected with the corresponding pin in the upper optical board to screen the interference of a burr, thereby successfully eliminating the false alarm fault in antenna-servo system of the CIN- RAD/SA radar of Shanwei.

Multi-omics revealed the mechanism of feed efficiency in sheep by the combined action of the host and rumen microbiota

This study was conducted to investigate potential regulatory mechanisms of feed efficiency(FE)in sheep by linking rumen microbiota with its host by the multi-omics analysis.One hundred and ninety-eight hybrid female sheep(initial body weight=30.88±4.57 kg;4-month-old)were selected as candidate sheep.Each test sheep was fed in an individual pen for 60 days,and the residual feed intake(RFI)was calculated.The ten candidate sheep with the highest RFI were divided into the Low-FE group,and the ten with the lowest RFI were divided into the High-FE group,all selected for sample collection.The RFI,average daily gain and average daily feed intake were highly significantly different between the two experimental groups(P<0.05).Compared with Low-FE group,the insulin-like growth factor-1 and very low-density lipoprotein in serum and the propionate in rumen significantly increased in High-FE group(P<0.01),but the acetate:propionate ratio in rumen significantly decreased in High-FE group(P=0.034).Metagenomics revealed Selenomonas ruminantium,Selenomonas sp.and Faecalibacterium prausnitzii were key bacteria,and increased abundance of the genes encoding the enzymes for cellulose degradation and production of propionate in High-FE group.The results of proteomics and section showed the rumen papilla length and expression of carbonic anhydrase and Na^(+)/K^(+)-ATPase were significantly higher in High-FE group(P<0.05).On the other hand,the acetyl-CoA content significantly increased in the liver of High-FE group(P=0.002).The relative expression levels of insulin-like growth factor-1 and apolipoprotein A4 genes were significantly up-regulated in the liver of High-FE group(P<0.05),but relative expression level of monoacylglycerol O-acyltransferase 3 gene was significantly down-regulated(P=0.037).These findings provide the mechanism by which the collaborative interaction between rumen microbiota fermentation and host uptake and metabolism of fermentation products impacts feed efficiency traits in sheep.

Multi-omic Analyses Shed Light on The Genetic Control of High-altitude Adaptation in Sheep

Sheep were domesticated in the Fertile Crescent and then spread globally,where they have been encountering various environmental conditions.The Tibetan sheep has adapted to high altitudes on the Qinghai-Tibet Plateau over the past 3000 years.To explore genomic variants associated with high-altitude adaptation in Tibetan sheep,we analyzed Illumina short-reads of 994 whole genomes representing∼60 sheep breeds/populations at varied altitudes,PacBio High fidelity(HiFi)reads of 13 breeds,and 96 transcriptomes from 12 sheep organs.Association testing between the inhabited altitudes and 34,298,967 variants was conducted to investigate the genetic architecture of altitude adaptation.Highly accurate HiFi reads were used to complement the current ovine reference assembly at the most significantly associatedβ-globin locus and to validate the presence of two haplotypes A and B among 13 sheep breeds.The haplotype A carried two homologous gene clusters:(1)HBE1,HBE2,HBB-like,and HBBC,and(2)HBE1-like,HBE2-like,HBB-like,and HBB;while the haplotype B lacked the first cluster.The high-altitude sheep showed highly frequent or nearly fixed haplotype A,while the low-altitude sheep dominated by haplotype B.We further demonstrated that sheep with haplotype A had an increased hemoglobin–O_(2) affinity compared with those carrying haplotype B.Another highly associated genomic region contained the EGLN1 gene which showed varied expression between high-altitude and low-altitude sheep.Our results provide evidence that the rapid adaptive evolution of advantageous alleles play an important role in facilitating the environmental adaptation of Tibetan sheep.

Kagome晶格补偿型半金属Ni_(3)In_(2)S_(2)创纪录的高迁移率和极大磁电阻现象

具有Kagome晶格的晶体有很多有趣的性质,包括受挫磁阻、电荷有序、拓扑态、超导和关联现象.为了在电子学和自旋电子学应用中实现高性能Kagome晶格化合物,需要对能带结构仔细调整.本文采用输运测量、角分辨光电子能谱和从头计算等方法研究了Kagome晶格晶体Ni_(3)In_(2)S_(2)的电子结构.输运测量表明,Ni_(3)In_(2)S_(2)是一种在Kagome晶格材料中具有创纪录的高载流子迁移率(空穴和电子迁移率分别约为8683和7356 cm^(2)V^(-1)S^(-1))和极大磁电阻(在2 K和13 T时为15,518%)的补偿半金属.Ni在Kagome晶格中的3d电子导致的非直接带隙、小的电子/空穴口袋和大的带宽的能带结构特征很好地解释了这些特殊的性质.这项工作表明,晶体场和掺杂是优化Kagome晶格晶体输运特性的关键因素.我们的工作为Kagome晶格半金属在电子学和自旋电子学方面的应用提供了材料基础和优化路径.

拓扑异质结(PbSe)_(5)(Bi_(2)Se_(3))_(6)高压诱导超导电性研究

最近,天然异质结(PbSe)_(5)(Bi_(2)Se_(3))_(6)在理论上预测并实验证实为拓扑绝缘体.本文通过高压原位量子调控在(PbSe)_(5)(Bi_(2)Se_(3))_(6)中成功引入超导电性.当压力增加到10 GPa时,超导电性突然出现,T_(c)约为4.6 K,随后T_(c)急剧下降.值得注意的是,当进一步施加压力到30 GPa以上时,出现了一种新的超导态,且T_(c)直到本实验最高压力仍未饱和.结合XRD和拉曼光谱,我们认为(PbSe)_(5)(Bi_(2)Se_(3))_(6)中两个超导态的出现与压力诱导的结构相变有关.拓扑异质结压力下出现新的量子态,为进一步研究拓扑和超导的关系提供了一个良好的平台.

Phase Transformation in Al/Zn Multilayers during Mechanical Alloying

In this work,mechanical alloying of the alternating stacked pure Al and Zn thin foils was accomplished via high-pressure torsion(HPT).In the alloyed Al-Zn system,an exotic phase transformation from hexagonal close-packed(HCP)to face-centered cubic(FCC)was identified.The atomic-scale evolution process and underlying mechanism of phase transformation down to atomic scale are provided by molecular dynamics simulation and high-resolution transmission electron microscopy.The HCP→FCC phase transformation was attributed to the sliding of Shockley partial dislocations generated at the Al-Zn grain boundaries,which resulted in an[2110][011]and(0001)/(111)orientation relationship between the two phases.This work provides a new approach for the in-depth study of the solid phase transformation of Al-Zn alloys and also shed lights on understanding the mechanical properties of the HPT processed Al-Zn alloys.

ABE-induced PDGFD start codon silencing unveils new insights into the genetic architecture of sheep fat tails

Sheep is an important livestock species raised globally to produce meat,milk,wool,and other by-products.During the Neolithic Revolution,sheep were domesticated in the Fertile Crescent of Southwest Asia around 10,000 years ago(Chessa et al.,2009).

Professional Development of County-level Physical Education Teachers from the Perspective of the New Curriculum Standards:A Case Study of Huaiji County

Using methods such as questionnaire survey and literature review,a survey was conducted on the professional development of physical education teachers in Huaiji County under the background of the new curriculum standards.The research results found that physical education teachers in Huaiji County have a relatively good distribution structure in terms of teaching experience,age,and education level,but the gender ratio and professional title ratio need to be improved.In terms of professional competence,teachers have shown good performance in teaching implementation ability,but there is still room for improvement in teaching design ability.A certain proportion of teachers still express dissatisfaction with professional title promotion,hardware configuration satisfaction,salary and benefits,and school reward mechanisms.Based on this,this study proposes some measures to improve the professional development level of county-level physical education teachers,such as enhancing teachers teaching design and implementation abilities,strengthening the cultivation of technical action demonstration abilities,improving hardware configuration satisfaction and teaching effectiveness reflection level,strengthening guidance and support for teachers professional development,and enhancing the promotion and implementation of post employment training.