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Composite topological nodal lines penetrating the Brillouin zone in orthorhombic AgF_(2)

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npj Computational Materials 2019年第1期5卷 694-701页

作者： Dexi Shao Huaiqiang Wang Tong Chen Pengchao Lu Qinyan gu Li sheng Dingyu xing Jian Sun National Laboratory of Solid State Microstructures and Department of Physics Nanjing University210093 NanjingChina Collaborative Innovation Center of Advanced Microstructures 210093 NanjingChina

It has recently been found that nonsymmorphic symmetries can bring many exotic band ***,based on symmetry analysis,we predict that materials with time-reversal symmetry in the space group of Pbca(No.61)possess rich symmetry-enforced band crossings,including nodal surfaces,fourfold degenerate nodal lines and hourglass Dirac loops,which appear in triplets as ensured by the cyclic permutation *** take Pbca AgF_(2) as an example in real systems and studied its band structures with ab initio ***,in the absence of spin-orbit coupling(SOC),besides the above-mentioned band degeneracies,this system features a nodal chain and a nodal armillary sphere penetrating the Brillouin zone(BZ).While with SOC,we find a new configuration of the hourglass Dirac loop/chain with the feature traversing the BZ,which originates from the splitting of a Dirac loop confined in the ***,guided by the bulk-surface correspondence,we calculated the surface states to explore these bulk nodal *** evolution of these interesting nodal phenomena traversing the BZ under two specific uniaxial strains is also discussed.

关键词： nodal symmetry Brillouin

Peculiar early-type galaxies with central star formation

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Research in Astronomy and Astrophysics 2012年第5期12卷 485-499页

作者： Chong Ge Qiu-sheng gu School of Astronomy and Space Science Nanjing University Nanjing 210093 China Key Laboratory of Modern Astronomy and Astrophysics Nanjing University Ministry of Education Nanjing 210093 China

Early-type galaxies （ETGs） are very important for understanding the formation and evolution of galaxies. Recent observations suggest that ETGs are not simply old stellar spheroids as we previously thought. Widespread recent star formation, cool gas and dust have been detected in a substantial fraction of ETGs. We make use of the radial profiles of 9 - r color and the concentration index from the Sloan Digital Sky Survey database to pick out 31 peculiar ETGs with central blue cores. By analyzing the photometric and spectroscopic data, we suggest that the blue cores are caused by star formation activities rather than the central weak active galactic nucleus. From the results of stellar population synthesis, we find that the stellar population of the blue cores is relatively young, spreading from several Myr to less than one Gyr. In 14 galaxies with H I observations, we find that the average gas fraction of these galaxies is about 0.55. The bluer galaxies show a higher gas fraction, and the total star forma- tion rate （SFR） correlates very well with the H I gas mass. The star formation history of these ETGs is affected by the environment, e.g. in the denser environment the H I gas is less and the total SFR is lower. We also discuss the origin of the central star formation of these early-type galaxies.

关键词： galaxies elliptical and lenticular cD- galaxies: peculiar - galaxies evolution

Fault Tree Analysis of Dust Suppression Mechanism in a Spray System with Wetting Agent

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Journal of Central South University 2000年第3期12卷 117-123页

作者： WU Chao gu De-sheng College of Resources Environmental and Civil EngineeringCentral South UniversityChangsha 410083China

By using the fault tree analysis in reliability theory as the systematical analysis approach, the dust suppression mechanism in a spray system with wetting agent is shown in a logic tree and some graphical models. From these diagrams, all factors related to the spray system and their cause and effect relationship can be seen clearly. Based on the built logic tree, several mathematical models and new ideas for expressing the dust suppressing efficiency in the spray system are put forward. The significance of all factors related to the efficiency of suppressing dust is qualitatively described. Furthermore, the new concepts, such as, the effective reaction time between dust particle and droplet, the expansion phenomenon of laden dust droplet, the functions of volatile and the relative size distribution efficiency of wetting agent are presented. All this richenes the existing mechanism of dust abatement by spraying wetting agent. At last, several problems that need to be further investigated are also suggested in the paper.

关键词： coal dust spray system wetting agent fault tree analysis mechanism efficiency approaches

Cohomology groups of a new class of Kadison-Singer algebras

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Science China Mathematics 2024年第3期67卷 593-606页

作者： guangyu An xing Cheng Jun sheng School of Mathematics and Data Science Shaanxi University of Science and TechnologyXi’an 710021China

Let N be a maximal discrete nest on an infinite-dimensional separable Hilbert space H,ξ=∑^(∞)_(n=1)en/2n be a separating vector for the commutant N',E_(ξ)be the projection from H onto the subspace[Cξ]spanned by the vectorξ,and Q be the projection from K=H⊕H⊕H onto the closed subspace{(η,η,η)^(T):η∈H}.Suppose that L is the projection lattice generated by the projections(E_(ξ) 0 0 0 0 0 0 0 0),{(E 0 0 0 0 0 0 0 0):E∈N},(I 0 0 0 I 0 0 0 0) and *** show that L is a Kadison-Singer lattice with the trivial ***,we prove that every n-th bounded cohomology group H~n(AlgL,B(K))with coefficients in B(K)is trivial for n≥1.

关键词： Kadison-Singer algebra Kadison-Singer lattice derivation cohomology group

High Efficiency Dust Scrubbers for Continuous Miner in Underground Mines

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Journal of Central South University 2000年第4期12卷 205-211页

作者： WU Chao gu De-sheng College of Resources Environment and Civil EngineeringCentral South UniversityChangsha 410083China

Based on the experimental data by a full scale test model and the relevant existing achievements, four new concepts of group dust scrubbers were designed in the paper. The new dust scrubbers consist of two to four common dust separators in series: wet fan, wet Venturi and foam filter bed. Wetting and foaming agents are used to increase the efficiency of dust separation. High efficiency is not required for each part of the group dust scrubbers, but the whole system has a high working reliability. All parts of the group dust scrubbers have the most suitable separating efficiency for different size and concentration of dust particles in airflow, according to their technical features. Four group dust scrubbers have a high efficiency from 94.4% to 99.7% for separating respirable dust at a rational cost.

关键词： group dust scrubber foaming agent wetting agent wet-fan scrubber wet-Venturi scrubber foam filter bed continuous miner underground mine

Microstructural evolution and mechanical properties of 55NiCrMoV7 hot-work die steel during quenching and tempering treatments

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Advances in Manufacturing 2021年第4期9卷 520-537页

作者： xing-sheng Yu Chuan Wu Ru-xing Shi Ya-Sha Yuan Luoyang CITIC HIC Casting&Forging Co. LtdLuoyang 471039HenanPeople’s Republic of China National-Local Joint Engineering Laboratory of Intelligent Manufacturing Oriented Automobile Die&Mould Tianjin University of Technology and EducationTianjin 300222People’s Republic of China CITIC Heavy Industries Co. LtdLuoyang 471039HenanPeople’s Republic of China

55NiCrMoV7 hot-work die steel is mainly used to manufacture heavy forgings in the fields of aerospace and *** study aims to clarify the effects of heat treatment on the microstructural evolution and mechanical properties of the steel,in order to find out an optimal heat treatment scheme to obtain an excellent balance of strength,ductility and *** steel was quenched at temperature from 790℃ to 910℃ followed by tempering treatments of 100–650℃ for 5 *** mechanical property tests were carried out by tensile,impact toughness and *** microscope(OM),scanning electron microscope(SEM)and transmission electron microscope(TEM)were used to observe the austenite grains,lath martensite,carbides and fracture *** results show that the quenching temperature mainly influences the austenite grain size and the volume fraction of undissolved carbides(UCs),while the tempering temperature mainly influences the size and morphology of the martensite with a body centered cubic(BCC)and the carbides with a face centered cubic(FCC).The mechanical properties of the steel,including yield and tensile strength,ductility,impact toughness and hardness,get an excellent balance at a quenching range of 850–870*** the tempering temperature increases,the yield and tensile strength and hardness decrease,while the ductility and impact toughness *** variation trends can be further verified by fracture SEM observation and *** with a macro-micro coupled finite element(MMFE)modeling technique,the cooling rate,microstructural evolution and yield strength of the steel were predicted and compared with the tested data.

关键词： Hot-work die steel Microstructural evolution Mechanical properties Heat treatment Macro-micro coupled modeling and simulation

Photometric redshifts of galaxies from SDSS and 2MASS

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Chinese Journal of Astronomy and Astrophysics 2009年第4期9卷 390-400页

作者： Tao Wang Jia-sheng Huang Qiu-sheng gu Department of Astronomy Nanjing University Nanjing 210093 China Harvard-Smithsonian Center for Astrophysics 60 Garden Street Cambridge MA 02138

In order to find the physical parameters which determine the accuracy of pho- tometric redshifts, we compare the spectroscopic and photometric redshifts （photo-z＇s） for a large sample of -80000 SDSS-2MASS galaxies. Photo-z＇s in this paper are estimated by using the artificial neural network photometric redshift method （ANNz）. For a subset of -40000 randomly selected galaxies, we find that the photometric redshift recovers the spectroscopic redshift distribution very well with rms of 0.016. Our main results are as follows：（1） Using magnitudes directly as input parameters produces more accurate photo-z＇s than using colors; （2） The inclusion of 2MASS （J, H, Ks） bands does not improve photo-z＇s significantly, which indicates that near infrared data might not be important for the low-redshift sample; （3） Adding the concentration index （essentially the steepness of the galaxy brightness profile） as an extra input can improve the photo-z＇s estimation up to -10 percent; （4） Dividing the sample into early- and late-type galaxies by using the concentration index, normal and abnormal galaxies by using the emission line flux ratios, and red and blue galaxies by using color index （g - r）, we can improve the accuracy of photo-z＇s significantly; （5） Our analysis shows that the outliers （where there is a big difference between the spectroscopic and photometric redshifts） are mainly correlated with galaxy types, e.g., most outliers are late-type （blue） galaxies.

关键词： galaxies distances and redshifts-methods statistical-techniques pho-tometric

Inheritance of Powdery Mildew Resistance in Cucumber (Cucumis sativus L.) and Development of an AFLP Marker for Resistance Detection

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Agricultural Sciences in China 2007年第11期6卷 1336-1342页

作者： ZHANG Su-qin gu xing-fang ZHANG sheng-ping ZOU Zhi-rong Institute of Vegetables and Flowers Chinese Academy of Agricultural Sciences Beijing 100081 P.R.China Agricultural College Guizhou University Guiyang 550025 P.R.China College of Horticulture Northwest A ＆ F University Yangling 712100 P.R.China

Cucumber powdery mildew is one of the most destructive diseases of cucumber throughout the world. In the present study, inheritance of powdery mildew resistance in three crosses, and linkage of resistance with amplified fragment length polymorphism （AFLP） markers are studied to formulate efficient strategies for breeding cultivars resistant to powdery mildew. The joint analysis of multiple generations and AFLP technique has been applied in this study. The best model is the one with two major genes, additive, dominant, and epistatic effects, plus polygenes with additive, dominant, and epistatic effects （E-l-0 model）. The heritabilities of the major genes varied from 64.26% to 97.82%, and susceptibility was incompletely dominant for the two major genes in the three crosses studied. The additive effects of the two major genes and the dominant effect of the second major gene were high, and the epistatic effect of the additive-dominant between the two major genes was the highest in cross I . In cross II, the absolute value of the additive effect, dominant effect, and potential ratio of the first major gene were far higher than those of the second major gene, and the epistatic effect of the additive-additive was the highest. The genetic parameters of the two major genes in cross III were similar to those in cross II. Correlation and regression analyses showed that marker E25/M63-103 was linked to a susceptible gene controlling powdery mildew resistance. The marker could account for 19.98% of the phenotypic variation. When the marker was tested on a diverse set of 29 cucumber lines, the correlation between phenotype and genotype was not significant, which suggested cultivar specialty of gene expression or different methods of resistance to powdery mildew. The target DNA fragment was 103 bp in length, and only a small part was found to be homologous to DNA in the other species evaluated, which indicated that it was unique to the cucumber genome.

关键词： cucumber (Cucumis sativus L.) powdery mildew resistance inheritance amplified fragment lengthpolymorphism (AFLP) molecular marker

Self-corrosion, electrochemical and discharge behavior of commercial purity Al anode via Mn modification in Al-air battery

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Rare Metals 2021年第12期40卷 3501-3511页

作者： guo-sheng Peng Jun Huang Yi-Cheng gu guang-sheng Song School of Materials Science and Engineering Anhui University of TechnologyMa’anshan 243002China Key Laboratory of Green Manufacturing and Surface Technology of Advanced Metal Materials Ministry of EducationAnhui University of TechnologyMa'anshan 243002China

The self-corrosion, electrochemical and discharge behavior of commercial purity Al anode via Mn modification in Al-air battery was studied by the hydrogen evolution, weight loss, electrical conductivity, electrochemical and discharge tests. Results show that the synergetic effects of the dissolved Mn and Mn-modifying Al_(3)Fe intermetallic decrease the weight loss and inhibit the hydrogen evolution of commercial purity Al in Na OH solution when minor Mn is introduced. However, more Mn addition leads to the formation of Al_6Mn intermetallic,which has little effect on the weight loss, but accelerates the hydrogen evolution. Mn introduction plays a positive role in activating Al anodes, resulting in a decrease in the anodic polarization and an increase in the discharge voltage. Among all the commercial purity Al-x Mn anodes, 0.1 wt% Mn addition exhibits the best discharge efficiency for Al-air battery.

关键词： Commercial purity Al Mn addition Corrosion Electrochemical activity Discharge behavior