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排序方式: 共有451条查询结果,搜索用时 31 毫秒
1.
The oxidation behavior in air at 973 K of theaustenitic stainless steels 18Cr8Ni and17Cr-2.5Ni-10.5Mn-2Cu-0.17N (low-nickel content), wasstudied in a thermobalance. The steels were heated fromroom temperature up to 973K at 10 K min-1, oxidizedfor 80 hr and then cooled to room temperature at 80 Kmin-1. The two steels had the same weightgains, 0.18 mg cm-2, which is equivalent tooxidation layers about 1.15 m theoretical thickness. In both cases, thegeneral shapes of the WS-1 (mgcm-2) curves vs. t (hours) were parabolic,but X-ray diffraction of the oxidized surfaces, surfaceand crosssection optical microscopy and SEM observations and EDSmicroanalysis show important differences betweenthem. 相似文献
2.
研究为在炼油污水的CAST工艺的主反应区中 ,通过恰当控制pH值和DO(污水中溶解氧含量 )值 ,可以使硝化与反硝化反应同步进行 ,在去除COD ,BOD的同时 ,也可提高其脱氮效果 ,从而得出DO的最佳值为 0 .8mg/L ,pH为 7.3~ 7.7之间。 相似文献
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4.
Gary Allenby Kathy Dodgson Paul Harper Adel Kassam Michael Leam Ian Dale Elaine Sullivan 《Journal of The Association for Laboratory Automation》2001,6(5):48
Advances in the field of automation have meant hitherto complex manual cell-based assays can now be automated. These improvements have brought significant enhancements in throughput, data fidelity and consistency, and allowed a reallocation of constrained resources.Building upon these improvements, we have linked our automated cell-based screening system, Assay Platform™, to Activity Base (IDBS), a software package designed to automate the analysis of HTS data. Customisation of this package has resulted in software that can identify ‘active’ compounds and re-pick them ‘on the fly’ from the original compound plates for triplicate re-testing without operator intervention.Based on an operator initially defining ‘normal’ parameters for assay activity in Activity Base, combined with an automated quality control software module that checks data fidelity, wells containing ‘active’ compounds can be re-picked and re-tested at the end of an automated screening run. Automating cell-based assays has significantly improved productivity, and, with the synergism of Activity Base, has given us greater power to complete each screening run and report ‘active’ compounds to Chemistry more rapidly. This article presents our approach to the automation of cell-based Fluorescent Imaging Plate Reader (FLIPR) screening together with automated active re-test confirmation using Activity Base. 相似文献
5.
交替缺氧/好氧CAST处理低ρ_(COD)/ρ_(TN)生活污水的脱氮研究 总被引:1,自引:0,他引:1
以低ρCOD/ρTN生活污水为处理对象,在连续和分段2种进水方式下分析了交替缺氧/好氧循环式活性污泥法工艺的脱氮性能及曝气需求量,并研究了分段进水方式下pH、ρDO和氧化还原电位(oxidation reduction potential,ORP)的变化规律.结果表明,连续进水方式下,系统TN平均去除率75.1%,系统因长期低负荷运行而发生污泥膨胀,污泥容积指数(sludge volume index,SVI)平均值为229 mL/g,同时,曝气量升至0.56 m3/h时,才能使NH4+-N去除率大于99%;采用分段进水方式时,系统TN平均去除率可提高至81.5%,污泥沉降性能良好,并且曝气量降至0.24 m3/h时,系统NH 4+-N去除率仍大于99%,节省了运行费用.此外,当采用分段进水时,反应区内的pH值、ρDO和ORP值曲线有较明显的变化规律,并与反应区内污染物浓度的变化有着较好的相关性. 相似文献
6.
低水温、低有机负荷条件下CAST工艺城市污水处理厂的启动调试及活性污泥培养 总被引:1,自引:0,他引:1
目的为北方城市污水处理的CAST工艺在冬季进水温度低和有机负荷低的条件下进行启动调试及活性污泥培养驯化提供经验,促进该工艺在寒冷地区的推广应用.方法采用接种法培养活性污泥,通过控制曝气量以减少曝气过程中的热量损失.结果在冬季进水温度低和有机负荷低的条件下,采用接种法培养驯化活性污泥20d就能完成污泥培养驯化,满足污水处理要求,使出水达到了设计标准.结论北方城市污水处理的CAST工艺在冬季启动调试及活性污泥培养时,采用接种法培养活性污泥能够克服有机负荷低的缺点,控制曝气量能够减少进水热量的损失,避免进水温度降低.为微生物的生长创造了条件,提高了污水处理效果. 相似文献
7.
《Materials Science & Technology》2013,29(3):399-402
AbstractThe microstructure of a multiphase NiAl-33.5Cr-0.5Zr intermetallic alloy was examined by SEM with energy dispersive spectroscopy and TEM. The tensile creep behaviour of the hot isostatically pressed NiAl-33.5Cr-0.5Zr alloy was studied. The results of the creep test indicated that all of the creep curves under the present test have similar characteristics: a short primary creep stage, a dominant tertiary creep stage, and nearly identical creep strains (~45%). The apparent stress exponent and the apparent activation energy were analysed and discussed. The mechanism of the creep deformation was also analysed by the observation of TEM. 相似文献
8.
《粉末冶金学》2013,56(4):315-321
AbstractLow porosity powder metallurgy compacts have been manufactured from treated elemental iron and cobalt powders sintered at 1150°C under an H2(g) atmosphere. Their microstructures consist of an interconnected mixed oxide network which encapsulates both the iron and cobalt phases. The production technique employed is an innovative process termed reacto-thermitic sintering (RTS), which leads to near full density and near net shape parts utilising conventional uniaxial compaction and mesh belt furnace practices. The RTS technique relies on microscale exothermic reaction between small quantities of added elemental Al and oxides present on the surface of the bulk powder, together with the bulk powder itself. This results in the production of a transient liquid phase which freezes rapidly and consolidates the compact without slumping. In order to generate an interconnected mixed oxide network, experiments were designed such that the Al powder reacts with the cobalt and the surface of the iron powder which is artificially doped with Fe and Cr oxides.Differential thermal analysis (DTA) and energy balance calculations revealed that the Al and the oxide coating reaction does not proceed directly. Instead the main contribution to the exothermic process is the reaction between Al and Co/Fe. The system does not exhibit true RTS behaviour and the interconnected network of mixed Al, Cr, and Fe oxides is created by subsequent reaction of Co-Al and Fe-Al intermetallics with the artificial Fe-Cr oxide coating on the Fe. The microstructure obtained exhibits negligible porosity with the metallic particles on the whole fully encapsulated by the oxide. 相似文献
9.
AbstractMetaliron powders of well controlled size and morphology were synthesised by thermal decomposition under hydrogen of precipitated ferrous oxalates. Green compacts were prepared by uniaxial pressing of metal powders at 290 MPa. The bending green strengths of compacts were measured.The precipitation of β-FeC2O4.2H2O oxalate from ammonium oxalate gives rise to the formation of spherical particles by aggregation ofelongated grains. Thermal decomposition of this oxalate from 400 to 500°C under hydrogen permits metal iron particles with a rough surface to be obtained. Decomposition occurring above 500°C induces a smoothness of the particle surface. Metal particles synthesised at 500°C show both surface roughness and micrometer sized primary grains.This specific microstructure has allowed the highest value ofcompact green strength (31·7 MPa) to be obtained.Acicular shaping of the β-FeC2O4.2H2O particles precipitated from oxalic acid involves, after decomposition, an increase in the surface roughness and shape irregularity of the metal particles, owing to an entanglement of the elementary grains. An exceptional value (about 60 MPa) for the metal compact green strength was thus obtained for this type of powder. 相似文献
10.
《粉末冶金学》2013,56(4):345-349
AbstractFatigue crack propagation rates under plane strain conditions have been investigated for three PM low alloy steels consolidated to high densities by rotary compaction followed by sintering and heat treatment. It is shown that the densities and properties are intermediate between those of pressed and sintered materials and of powder forged materials. Threshold stress intensities compare satisfactorily with those for wrought counterparts, but resistances to crack growth are inferior to those of wrought steels. Possible reasons for the properties of the rotary compacted materials are considered in the light of their microstructures and the behaviour of other PM materials. 相似文献