采用高能球磨法制备Cu质量分数为8％的Mo-Cu纳米复合粉末,研究了过程控制剂对复合粉末形貌特征的影响.利用扫描电子显微镜(SEM)分析手段对复合粉末的形貌特征进行分析.结果表明,球磨后复合粉末形貌呈现层片状;在相同的球磨参数条件下,添加过程控制剂硬脂酸(SA)和液体酒精,球磨颗粒间的团聚倾向变小,团聚颗粒尺寸较小,并且添加表面活性剂酒精的团聚粒度比添加硬脂酸(SA)的粒度更小且更均匀.

采用高能球磨法制备Mo-8wt％Cu纳米复合粉末,研究了球磨转速对复合粉末特性的影响.利用XRD、比表面积分析仪、激光粒度分析仪等分析手段对复合粉末的特性和晶粒尺寸和晶格畸变进行了测定.结果 表明,在相同的球磨条件下,随球磨转速的增大,粉末比表面积增大,费氏粒度减小,钼晶粒尺寸减小,晶格畸变增大;随球磨转速的增大,复合粉末表面活性增大,颗粒间的团聚倾向增大.

分析研究了电炉生产16MnCr5渗碳钢中非金属夹杂物的类型、组成、外形和分布.结果 表明:钢中存在CaO、Al2O3、MnO、Cr2O3、FeO、SiO2、MnS、M(C、N)和AlN等非金属夹杂物,其中以氧化物夹杂Al2O3为主,对性能产生的影响也较为严重;采用铝深脱氧工艺,可显著降低钢中w(T.O)和w(S)含量,同时非金属夹杂物总量也会达到较低水平.

Mo-8wt%Cu nanocomposite powders were fabricated by mechanical alloying, and full density alloy was obtained via liquid-phase sintering and post-treatment process.The microstructure of Mo-8wt%Cu alloy was investigated by scanning electron microscope (SEM), and the effects of process parameters on relative density, tensile strength and elongation were studied.The results indicate that the relative density of Mo-Cu alloy is 98.6% after sintering at 1 250 ℃ for 30 min, and its microstructure is composite network.The full density of Mo-Cu alloy can be obtained when specimens are treated through deformation strengthening process of rotating forging and hydrostatic extrusion.The tensile strength and elongation rate are 576 MPa and 5.8%, respectively, when hydrostatic extrusion deformation degree is 40%.

Heat shock proteins (Hsps) are common molecular chaperones present in all plants that accumulate in response to abiotic stress. Small heat shock proteins (sHsps) play important roles in alleviating diverse abiotic stresses, especially heat stress. However, very little is known about the MsHsp20 gene family in the wild apple Malus sieversii, a precious germplasm resource with excellent resistance characteristics. In this study, 12 putative M. sieversii Hsp20 genes were identified from RNA-Seq data and analyzed in terms of gene structure and phylogenetic relationships. A new Hsp20 gene, MsHsp16.9, was cloned and its function studied in response to stress. MsHsp16.9 expression was strongly induced by heat, and transgenic Arabidopsis plants overexpressing MsHsp16.9 displayed improved heat resistance, enhanced antioxidant enzyme activity, and decreased peroxide content. Overexpression of MsHsp16.9 did not alter the growth or development under normal conditions, or the hypersensitivity to exogenous ABA. Gene expression analysis indicated that MsHsp16.9 mainly modulates the expression of proteins involved in antioxidant enzyme synthesis, as well as ABA-independent stress signaling in 35S:MsHsp16.9-L11. However, MsHsp16.9 could activate ABA-dependent signaling pathways in all transgenic plants. Additionally, MsHsp16.9 may function alongside AtHsp70 to maintain protein homeostasis and protect against cell damage. Our results suggest that MsHsp16.9 is a protein chaperone that positively regulates antioxidant enzyme activity and ABA-dependent and independent signaling pathway to attenuate plant responses to severe stress. Transgenic plants exhibited luxuriant growth in high temperature environments.

采用机械合金化法制备Mo-10％Cu超细复合粉末,研究了球料比对复合粉末特性的影响.利用SEM、XRD、比表面积分析仪、激光粒度分析仪等分析手段对复合粉末的特性和形貌进行了表征和观察.结果表明,在相同的球磨条件下,随球料比的增大,粉末比表面积增大,粒度变小,晶粒尺寸减小,晶格畸变增大;随球料比的增大,复合粉末颗粒之间的团聚倾向加大.

After carburizing,quenching and tempering,the carbon concentration and hardness of 16 Mn Cr5 steel present gentle decreasing from the surface to the center without sudden change.The microstructure of carburized layer and center,depth of carburized layer,surface hardness and impact energy satisfy the technique requirements of some type camshaft.

The new developments of CeO2-based electrolytes are reviewed,especially the enhanced mechanism of ionic conductivity of doubled doping and CeO2-based composite electrolyte,and the development trends of CeO2-based electrolytes are proposed.

It has been widely shown that polyploidization can result in changes in cytosine methylation. However, little is known regarding how cytosine methylation changes in polyploids development, especially in polyploid trees. In this study, we investigated drifting changes of DNA methylation status at 5′-CCGG sites in the apical bud, young and mature leaf tissues of triploid black poplar ( Populus. euramericana ) with methylation-sensitive amplification polymorphism (MSAP) and assessed the expression of multiple DNA methyltransferases (MTases) and DNA demethylase during different developmental stages. MSAP analysis detected methylation levels at CG and CNG sites of diploid tissues reduced during development from bud to leaves, while for the triploid, methylation at CNG sites increased during development, but levels of methylation at CG sites first decreased in young leaves before increasing in mature leaves. MTase genes related to CG or CNG methylation were respectively preferential in different triploid tissues with high CG or CNG methylation levels. High expression of DNA demethylase was observed in tissue with high demethylation trends. These finding suggest CG and CNG methylation and their related enzymes are involved with different biological functions and networks of gene regulation in different developmental stages of triploid.

Research progress in composite electrolyte materials for intermediate-to-low temperature solid oxide fuel cell(SOFC)was introduced.The structure design,preparation,enhanced mechanism of conductivity and performance of single cell of Y doped ZrO2/insulator,doped CeO2/insulator,doped CeO2/inorganic salt and proton conductor based composite electrolyte materials were mainly reviewed.The possibility,existed problems and development trend of nanocomposite electrolyte materials applied in intermediate-to-low temperature SOFC were pointed out.

Adenine-induced chronic renal failure(CRF) rats was constructed as animal model and detected the change of TGF-β1 expression in the renal cortex of rats by the method of FQ-PCR and IHC.Thirty male Wistar rats were randomly assigned to the following groups: Normal Control Group(n=10),Pathological Control Group(PCG)(n=10) and Uremic Clearance Granules Treatment Group(UCG)(n=10).During first 6 weeks,rats in PCG and UCG were induced by gastric gavage of adenine(250 mg kg-1/d).During second 6 weeks,rats in UCG were treated with 2 mL solution of Uremic Clearance Granules.The rats were sacrificed at week 12.Blood urea nitrogen and serum creatinine levels were measured.mRNA expressions of transforming growth factor beta 1 and its downstream gene in the kidney tissue were assessed by RT-PCR,protein expressions of transforming growth factor beta 1 in the kidney tissue were assessed by immunohistochemistry.The results showed that(1) TGF-β1、CTGF、α-SMA、FN、Col-Ⅰ、Col-Ⅳ and PAI-1 mRNA levels in UCG was evidently lower than PCG(P<0.05) and(2) renal cortex TGF-β1 protein expression reduced from(3.81±0.08) to(1.86±0.09),with P<0.05 showing significant difference.Uremic Clearance Granule may ameliorate chronic renal failure in adenine-induced CRF rats.This effect of uremic clearance granule on CRF is probably related to suppressing overexpression of TGF-β1、CTGF、α-SMA、FN、Col-Ⅰ、Col-Ⅳ and PAI-1 mRNA and TGF-β1 protein in renal tissue.

Mo-8wt%Cu nano powders were fabricated by mechanical alloying,and the dense alloys were obtained via the liquid-phase sintering and post-treatment process.The microstructure of Mo-8wt%Cu alloy were investigated by scanning electron microscope(SEM),and the effects of process parameters on the density,tensile strength,the elongation and grain size were studied.The results indicate that the relative density of alloy is 98.6% after sintering at 1250℃ for 30 min,and its microstructure is composite network.The full density of Mo-Cu alloy is achieved when specimens are treated through hydrostatic extrusion transformation processes.The tensile strength is 576MPa,and the elongation is 5.8% when hydrostatic extrusion transformation degree is 40%.

The chromosomes(2n=2x=38) of Populus are composed of one pairs of large and 17 pairs small similar chromosomes at the morphological level.Three probes(18S-5.8S-25S rDNA,5S rDNA and Arabidposis-type telomere repeats) were located on the chromosomes of the seven Populus species which belong to the five Populus sections(Leuce,Aigeiros,Tacamahaca,Leucoides,Turanga),by using the multicolor fluorescence in situ hybridization(M-FISH).The rDNA locus and measuring data according to the chromosomes end displayed by the telomere hybridization fluorescence were applied to discriminate of the similar chromosomes and karyotype in decreasing order.The two 18S-5.8S-25S rDNA sits were observed in the Populus species except of P.euphratica where only one was identified.The major 18S-28S rDNA site was on the former chromosome.One 5S rDNA site was characterized in all seven.The satellites were observed in the seven Populus species and colocated with the 18S-28S rDNA sites.The multicolor FISH will be useful for identifying the chromosomes and karyotyping,and it can provide more information about difference among the species at the cytogenentic level.

Abstract Triploidy is a widespread phenomenon in cultivated and natural breeding plants and it can confer some growth advantages. Here, we analyzed genome-wide gene expression in triploid Populus euramericana (black poplar) using the Affymetrix poplar microarray to detect any possible correlation between triploid vigor and a unique gene expression profile. Among the 38,400 transcripts that were detected in triploid poplar, 1,564 and 2,015 genes were up- or downregulated, respectively, compared with the diploid. The majority of the upregulated genes in the triploid were associated with carbon and nitrogen metabolism, especially lignin and secondary metabolism. Other genes upregulated in the triploid included genes involved in sugar transport, and brassinosteroid (BR) and auxin metabolism. Downregulated genes were mostly related to the assembly and biosynthesis of ribosomes and the nucleosome macromolecular complex. The results suggested that BR and auxin levels were crucial in controlling sugar transport, photosynthesis and cell wall biosynthesis. Downregulated genes were associated with chromatin regulation in the triploid. The information from this analysis could provide an insight into the vigor of triploid poplar.

Mo-3wt%Cu and Mo-10wt%Cu composite powders was processed by using a technology of mechanical alloying for a range of milling times up 50 h. An analysis was made on the micrograph and character of Mo-Cu composite powders by SEM and XRD, and solubility of Cu in Mo was studied by thermodynamic method. The results indicate that ultrafine and very homogeneous composite powders can be fabricated by using a technology of mechanical alloying, average crystallite size was about 80 nm; from thermodynamic balance, increasing solubility of Cu in Mo through crystal refinement can be expressed by numerical simulation.

To investigate whether DNA hypomethylation is present in rats with chronic renal fairlure and to assess the possible sequence fragments related to the DNA hypomethylation, adenine-induced Chronic Renal Failure(CRF) rat as animal model was constructed and detected the change of Hcy concentration in the serum of rats by the method of HPLC.The extent and pattern of methylation in the genome from the cortex of kidney of CRF rats were analyzed by the technique of methylation-sensitive amplified polymorphism(MSAP).The results showed that:(1) Concentration of Hcy in the serum of CRF rats raised up to(16.64±1.57)μmol/L,compared to(10.56±1.20)μmol/L under normal conditions,with P<0.05 showing significant difference.(2) Methylation rate in the genome from the cortex of kidney of CRF rats reduced to(38.43±3.27)%,compared to(41.95±1.94)%under normal conditions, with P<0.05 showing significant difference.(3) Differentially-methylated fragments involved many genes including several genes related to methyltransferase.The results suggest CRF rats suffer from hyperhomocysteinemia and the pattern of methylation in the genome changes significantly.

Mo-3wt%Cu ultrafine composite powder was prepared by mechanical alloying process,systematic investigeation were carried out on the structural change.Surfacial characteristic and thermal stability of the Mo-3wt%Cu high energy milled powders using a combination of X-ray powder diffraction,brunauer-emmett-teller(BET)nitrogen adsorption technique and differential thermal analysis assited by DTA.The experimental results showed that ball-milled could produce an ultrafine composite powedrs in which large lattice distortion,supersolidus solution and solubility extension of Mo in phase were occurred due to the fast diffusion induced by high density of lattice defects and nanograin boundaries.BET results provide a further evidence that milling led the specific surface area of powedrs surface meso pore,pore size to decrease and micro pores to produce.

The methylation-sensitive amplification polymorphism(MSAP)is used to analyze the levels and patterns of methylation in Yali pear autopolyploid(Pyrus.bretschneideri Rehd. cv.'Yali').We select twenty-two primers combinations to reveal the cytosine methylation polymorphism among the autopolyploid(2×,3×,4×).And it amount to 954 sites from 100 to 500 bp on the gel electrophoresis.It is suggested that the identified sites of diploid,triploid and tetraploid is 831,886 and 852,and the percentage of total methylation sites of the three autopolyploid is 15.5%,20.0%,16.8%respectively.Fully methylation rate of them is 9.7%, 11.9%,9.7%.The percentage of the same cytosine methylation patterns among the autopolyploid is 69.2%,and the different patterns is 5.5%.The rate that one autopolyploid methylation patterns is identical to another is 25.4%.And 41.4%of methylation cytosine patterns in the offspring(triploid)differ from that of the parents(diploid and tetraploid).

Polyploidization is known to accompany altered DNA methylation in higher plants, which plays an important role in gene expression regulation and maintaining genome stability. While the characteristics of DNA methylation in different polyploid plants are still to be elucidated; here, status of genomic DNA methylation in a series of diploid, triploid, and tetraploid annual herbaceous plants (watermelon and Salvia) and woody perennials (pear, Poplar, and loquat) were explored by methylation-specific amplified polymorphism analysis. The results indicated that levels of DNA methylation in triploid watermelon and Salvia were lower than their diploid parents. In triploid Poplar and pear, higher levels of DNA methylation were detected, and no significant difference was observed between triploid and tetraploid in all tested materials. Further data analysis suggested that about half of the total detected sites underwent changes of DNA methylation patterns in triploid watermelons and Salvia, as well as an obvious trend towards demethylation. However, the changes of DNA methylation patterns in three triploid woody perennials were only 17.54-33.40%. This implied that the characteristics of DNA methylation are significantly different during the polyploidization of different plant species. Furthermore, the results suggested that the level of DNA methylation was nonlinearly related to the ploidy level, and triploid plants displayed more interesting DNA methylation status. The characteristics and possible functions of DNA methylation in different ploidy series are further discussed.