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Influence of carbon content on wear resistance and wear mechanism of Mn13Cr2 and Mn18Cr2 cast steels

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China Foundry 2015年第1期12卷 39-47页

作者： Ding-shan Lu Zhong-yi Liu Wei Li Zhao Liao Hui Tian Jian-zhong xian Department of Materials Science and Engineering Jinan University Engineering Research Center of Wear Resistant Materials Jinan University Guangxi Great Wall Mining Machinery Equipment Manufacturing Company

By means of impact abrasion tests, micro-hardness tests, and worn surface morphology observation via SEM, a comparison research based upon different impact abrasive wear conditions was conducted in this research to study the influence of different carbon contents(1.25 wt.%, 1.35 wt.%, and 1.45 wt.%) on the wear resistance and wear mechanism of water-quenched Mn13Cr2 and Mn18Cr2 cast steels. The research results show that the wear resistance of the Mn18Cr2 cast steel is superior to that of the Mn13Cr2 cast steel under the condition of the same carbon content and different impact abrasive wear conditions because the Mn18Cr2 cast steel possesses higher worn work hardening capacity as well as a more desirable combination of high hardness and impact toughness than that of the Mn13Cr2 cast steel. When a 4.5 J impact abrasive load is applied, the wear mechanism of both steels is that plastic deformation fatigue spalling and micro-cutting coexist, and the former dominates. When the carbon content is increased, the worn work hardening effect becomes increasingly dramatic, while the wear resistance of both steels decreases, which implies that an increase in impact toughness is beneficial to improving the wear resistance under severe impact abrasive wear conditions. Under the condition of a 1.0 J impact abrasive load, the wear mechanism of both steels is that plastic deformation fatigue spalling and micro-cutting coexist, and the latter plays a leading role. The worn work hardening effect and wear resistance intensify when the carbon content is increased, which implies that a higher hardness can be conducive to better wear resistance under low impact abrasive condition.

关键词： high manganese steel carbon content water-quenched hardness-toughness combination wear-resistance wear mechanism

Mulching with plastic film improved the root quality of summersown sweet potato(Ipomoea batatas(L).Lam.)in northern China

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Journal of Integrative Agriculture 2019年第5期18卷 982-991页

作者： HOU Fu-yun DONG Shun-xu XIE Bei-tao ZHANG Hai-yan LI ai-xian WANG Qing-mei Crop Research Institute Shandong Academy of Agricultural Sciences/Scientific Observation and Experimental Station of Tuber and Root Crops in Huang-Huai-Hai RegionMinistry of Agriculture and Rural Affairs

The root quality of sweet potato cultivated during the summer season is poor in northern China;thus,this study was conducted to determine whether root quality could be improved through mulching with plastic film(MPF).The effect of MPF on root starch and its composition,the activity of starch synthesis enzymes,and other quality-related parameters were investigated in two purple flesh sweet potato cultivars,Jishu 18 and Ayamurasaki(Aya).The results indicated that root dry matter,anthocyanin content,adenosine triphosphate(ATP),and starch content were higher in both cultivars under the MPF treatment than those under the control *** root adenosine diphosphate glucose pyrophosphorylase/uridine diphosphate glucose pyrophosphorylase(ADPGPPase/UDPGPPase)activity and adenosine triphosphatease(ATPase)activity were increased using ***,under the MPF treatment,the amylose content,soluble sugar content,and granule-bound synthase(GBSS)activity increased in Jishu 18 but decreased in Aya,and the amylopectin content,protein content,and soluble starch synthase(SSS)activity decreased in Jishu 18 but increased in ***,MPF seems benifit to improve the quality of sweet potato,but the effects of this treatment condition may be dependent on the cultivar.

关键词： mulching with plastic film summer-sown sweet potato root quality starch

Attachment of tyrosinase on mixed self-assembled monolayers for the construction of electrochemical biosensor

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Chinese Chemical Letters 2010年第10期21卷 1239-1242页

作者： Xue Ping Ji xian Rui Li Na Wang Rui Xing Ni Xiao Hong Liu Hua ai Xiong Department of Medical Chemistry Hebei Medical University Shijiazhuang 050017 China

A mixed self-assembled monolayers （SAMs） of thioctic acid （T-COOH） and thioctic acid amide （T-NH2） were used to immobilize tyrosinase for fabricating biosensor. The results showed that the mixed SAMs prepared from solution at the ratio of 1：4 provided an excellent microenvironment for enzymatic reaction between tyrosinase and substrate. The biosensor exhibited a fast response and high sensitivity for sensing substrate.

关键词： Biosensor Tyrosinase Catechol Self-assembled monolayers Gold electrode

Globals of Completely Regular Monoids

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Communications in Mathematical Research 2015年第3期31卷 222-228页

作者： Wu Qian-qian Gan ai-ping Du xian-kun College of Mathematics and Information Science Jiangxi Normal University

An element of a semigroup S is called irreducible if it cannot be expressedas a product of two elements in S both distinct from itself. In this paper we showthat the class C of all completely regular monoids with irre... 详细信息

关键词： completely regular monoid irreducible element power semigorup

Role and recruitment of Th9 cells in liver cirrhosis patients

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Asian Pacific Journal of Tropical Biomedicine 2016年第4期6卷 330-334页

作者： shan-Yu Qin Jia-Xu Wang Mei Chen xian-Wen Yang Hai-Xing Jiang Department of Gastroenterology the First Affiliated Hospital of Guangxi Medical University

Objective:To investigate the role of T helper 9(Th9) cells in liver cirrhosis(LC) patients and whether chemokine receptor type 6(CCR6)/chemokine ligand 20(CCL20) axis is involving in the recruitment of Th9 cells into ***:Peripheral blood and liver tissue from 30 LC patients and 18 normal controls were *** frequency of Th9 cells and CCR4,CCR6 in the peripheral blood was tested by flow *** interleukin(IL)-9 and CCL20 levels were tested by enzyme-linked immunosorbent *** staining was used to detect a-smooth muscle actin,CCR6 and CCL20 expression in liver ***:The frequency of Th9 cells in LC patients was significantly increased compared with controls(P < 0.05).The serum IL-9 level and CCL20 level increased markedly in LC patients compared with controls(P < 0.05),and IL-9 was positively correlated to Th9 cells and ***,the frequency of Th9 cells was correlated to prothrombin time,total bilirubin level,hyaluronic acid and type IV collagen in LC *** also found that Th9 cells in LC patients expressed higher frequency of CCR4+,CCR6+(P < 0.05).Compared with normal controls,the expression of CCR6 and CCL20 in LC tissue were significantly elevated(P < 0.05).The expression of a-smooth muscle actin was correlated to the CCR6 and CCL20 in liver tissue of LC ***:This study suggests that Th9 cells may participate in the pathogenesis of LC,and the recruitment of Th9 cells into liver tissue might be through CCL20/CCR6 axis.

关键词： Th9 cells Cirrhosis Interleukins-9 CCR6/CCL20 axis

Effect of pressurizing speed on filling behavior of gradual expansion structure in low pressure casting of ZL205A alloy

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China Foundry 2018年第4期15卷 276-282页

作者： shan-guang Liu Chuan-biao Luo Guo-ai Li Wen-lin Gao Zheng Lu Sheng-long Dai Beijing Institute of Aeronautical Materials Beijing 100095China

The mold filling behavior of gradual expansion structure in low pressure casting was studied by two phase flow model using the Volume of Fluid method, and was verified by water simulation with a Plexiglas mold. To get smooth mold filling process and provide a guide for the pressurizing speed design in the producing practice, the mathematical model with the pressurizing speed, expansion angle and height of the gradual expansion structure was established. For validation experiments, ZL205 A alloy castings were produced under two different pressurizing speeds. Weibull probability plots were used to assess the fracture mechanisms under different pressurizing speeds. Mechanical properties of ZL205 A alloy were applied to assess the entrainment of oxide film. The results show that the filling process of a gradual expansion structure in a low pressure casting can be divided into the spreading stage and filling stage by gate velocity. The gate velocity continues to increase in the gradual expansion structure, and increases with the increase of pressurizing speed or expansion angle. Under the effect of the falling fluid raised by the jet flow along the sidewall, the fluid velocity decreases in the jet zone from ingate to free surface. As such, oxide film entrainment does not occur when the gate velocity is greater than the critical velocity, andthe gate velocity no longer reflects the real state of the free surface. The scatter of the mechanical properties is strongly affected by the entrainment of oxide films.

关键词： low pressure casting two phase flow water simulation oxide film ZL205A alloy

Dispersal patterns of Reeves's pheasant based on genetic and behavioral evidence

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Current Zoology 2024年第4期70卷 480-487页

作者： Shuai Lu xian Hou shan Tian Zhengxiao Liu Yunqi Wang Ting Jin Jianqiang Li Pengcheng Wang Jiliang Xu School of Ecology and Nature Conservation Beijing Forestry UniversityBeijing 100083China State Key Laboratory of Efficient Production of Forest Resources Bejing Forestry UniversityBeijing 100083China Jiangsu Key Laboratory for Biodiversity and Biotechnology College of Life SciencesNanjing Normal UniversityNanjing 210o23China

Dispersal is an important life history trait that plays a crucial role in avoiding *** the dispersal pattern of a threatened species facilitates conservation *** species of Galliformes are forest-dwelling terrestrial birds with a weak dispersal ability and high conservation ***,little is known about the dispersal behavior and dispersal pattern of Galliformes species such as Reeves's pheasant Syrmaticus reevesi,a globally vulnerable species endemic to ***,we integrated behavioral and genetic analyses to inves-tigate the dispersal pattern of Reeves's *** results revealed that both females and males would disperse,although the overall dispersal pattern was more likely to be ***'s pheasant population had a low level of genetic diversity and a mild level of *** low genetic diversity was resulted from fragmented habitat,and male-biased dispersal may reduce the opportunity of *** research indicated that sex-biased dispersal patterns may be a behavioral mechanism adopted by wildlife to avoid inbreeding inafragmented habitat.

关键词： animal behavior dispersal Gallformes genetic diversity satellite tracking.

Lamellar aspect-ratio and thickness-dependent strength-ductility synergy in pure nickel during in-situ micro-tensile loading

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Journal of Materials Science & Technology 2023年第26期157卷 89-97页

作者： Zi-Meng Wang Yun-Fei Jia Kai-shang Li Yong Zhang Jia-Dong Cai xian-Cheng Zhang Hiroyuki Hirakata shan-Tung Tu Key Laboratory of Pressure Systems and Safety Ministry of EducationSchool of Mechanical and Power EngineeringEast China University of Science and TechnologyShanghai 200237China Department of Mechanical Engineering and Science Kyoto UniversityKyoto daigaku-katsuraNishikyo-kuKyoto 615-8540Japan

In order to overcome the trade-offbetween strength and ductility in traditional metallic materials,the gradient lamellar structure was fabricated through an ultrasound-aided deep rolling technique in pure Ni with high stacking fault energy after heat *** gradient lamellar Ni was successively di-vided into three ***-situ micro-tensile tests were performed in different regions to reveal the corresponding microscopic mechanical *** characterization techniques were adopted to explore the effects of microstructural parameters and defects on mechanical *** work demonstrates that the micro-tensile sample with small lamellar thickness and large aspect ratio possesses excellent strength and ductility when the loading direction is parallel to the long side of lamellar grain *** finding is helpful to the design of metallic material microstructure with superior com-prehensive *** one hand,the reason for high strength is that the strength increases with the decrease of lamellar thickness according to the Hall-Petch ***,initial dislocation density also participates in the strengthening *** the other hand,the deformation mechanisms include dislocation slip,grain rotation,and the effects of grain boundaries on dislocations,jointly contributing to good ductility.

关键词： Lamella In-situ micro-tensile test Strength-ductility synergy Aspect ratio Grain rotation

Single Nucleotide Polymorphism (SNP) Analysis of orexin Gene 5' Regulatory Region in Chinese Indigenous Cattle Populations

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Agricultural Sciences in China 2011年第8期10卷 1273-1279页

作者： ZHANG ai-ling ZHANG Li ZHANG Liang-zhi LAN xian-yong ZHANG Cun-lei ZHANG Cun-fang CHEN Hong Shaanxi Key Laboratory of Molecular Biology for Agriculture College of Animal Science and TechnologyNorthwest A＆F UniversityYangling 712100P.R.China Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding College of Animal ScienceSouth China Agricultural UniversityGuangzhou 510642P.R.China Agricultural College Guangdong Ocean UniversityZhanjiang 524000P.R.China College of Life Sciences Xuzhou Normal UniversityXuzhou 221000P.R.China

Orexin is an important neuropeptide that influences livestock＇s appetite and food intake and is closely related with livestock＇s growth and *** variations in the orexin gene 5＇ regulatory region might have an influence on the gene *** on the hypothesis,five overlapped fragments including 1 794 bp of orexin gene 5＇ regulatory region were investigated for single nucleotide polymorphisms （SNPs） by PCR-SSCP and DNA sequencing in three indigenous cattle populations.A total of five SSCP patterns observed revealed ten SNPs in the *** SSCP patterns genotypes （A and B） were exhibited in O-2 fragment and three （A,B and C） were found in O-5 fragment.O-2 contained four SNPs,viz.,-583 TC,-479 CT,-474 AT,and-451 *** another lous O-5,six SNPs were identified （-1 610 CG,-1 585 GA,-1 550 TC,-1 548 AC,-1 438 CT,and-1 431 CA）.Seven SNPs were found in transcription factor binding sites and four out of them existed in the core *** SNPs at-479,-474 and-451 did not change the putative recognition core sequences of their *** the mutation at-583 changed the binding sequence of EVI1 into NFA and created one new binding site for ZFHX *** three populations,the frequencies of A,B and C genotypes of O-2 were 0.2367,0.4842 and 0.2791,*** the A pattern of O-5 was preponderant （0.7549） and the other B pattern was not （0.2451）.But the frequencies of different SSCP variants varied across three cattle populations.B genotype in O-2 had significant associations to body weight （BW） and daily weight gain （DWG） in Nanyang cattle 6-and 12-mon aged and might serve as one potential candidate genetic marker for growth and development.

关键词： orexin gene promoter SNP cattle