不锈钢换热器失效分析

用原子吸收光谱分析了失效构件的化学成分,用X射线衍射技术分析了腐蚀产物的相成分,用SEM和金相显微镜分析了失效构件的断口形貌。分析结果表明,不锈钢换热器失效的原因是由氯离子引起的应力腐蚀开裂所致。     

低压燃油分配管稳压器开裂分析及改进

从尺寸对比、化学成分、金相分析、X-Ray分析等方面对燃油分配管稳压器Damper失效原因进行了分析,介绍了常用检测开裂的方法。提出了改进措施,成功地杜绝了因Damper焊缝位置不当导致的泄漏失效再次发生。     

化学镀镍换热器管束腐蚀破裂失效分析

针对化学镀镍换热器管束腐蚀破裂进行分析,采用XRD物相分析、EDS成分分析、力学性能测试、金相显微组织分析、SEM微观形貌分析、电化学测试等手段,分析了管束破裂的原因。结果表明,管柬外表面镍磷镀层局部发生破坏后对碳钢管束基体的加速电偶腐蚀是管束发生破裂的主要原因。     

不锈钢退火酸洗线引带断裂原因分析及防控措施

针对不锈钢退火酸洗线发生引带断裂事故，对断裂试样进行宏观检测、化学成分检测、金相分析和扫描电镜分析，发现J4侧因奥氏体晶界析出的铁素体相和出现沿晶裂纹是断带的根本原因，并提出了相应的防控措施。     

托板螺母冲压开裂原因分析

由0Cr17Ni5Mo3沉淀硬化不锈钢制造的托板螺母零件,在冲压拉伸成型过程中,在进行第一次及第二次冲压拉伸时零件发生开裂,大约有30%零件发生开裂.利用扫描电子显微镜、光学显微镜以及化学成分和力学性能的测试手段,对材料和断口进行深入研究,并开展了模拟试验.结果表明:裂纹是由于材料中的σ相引起的;最后确定了合适的固溶工...     

马氏体相变对304不锈钢点蚀发展过程的影响

采用模拟闭塞电池法和交流阻抗法研究了奥氏体304不锈钢形变诱发马氏体相变对点蚀发展过程中化学和电化学行为的影响。结果表明，随着马氏体含量的增加，闭塞区溶液pH值下降得更快，Cl^-迁入闭塞区的量更多。马氏体相的存在增强了材料的电化学活性，既减小了点蚀发展过程中钝化膜孔隙内的欧姆电阻，又减小了孔隙内的反应极化电阻，从而促进了点蚀发展。     

J4不锈钢及化学镀Ni-P和Ni-Cu-P镀层在液-固两相流中的冲刷腐蚀行为

用质量损失法系统研究了不同温度(25和50℃)和不同冲刷速率(0.63—1.88 m/s)下,J4不锈钢、Ni-P和Ni-Cu-P合金镀层,及对比材料316L不锈钢在液-固两相流(20%H_2SO_4+20 g/L Al_2O_3)中的冲刷腐蚀行为,结果表明:不锈钢和镀层的抗冲刷腐蚀性能由高到低依次为镀态Ni-Cu-P,镀态Ni-P,热处理态Ni-Cu P,316 L,J4,提高两相流介质温度均使它们的冲刷腐蚀速率增大。316L不锈钢在25℃液-固两相流介质中的冲刷腐蚀速率分别为镀态Ni-Cu P,镀态Ni-P和热处理态Ni-Cu-P镀层的8.5倍,8倍和2.6倍以上,而在50℃下分别为392倍,80倍和14.8倍以上;J4不锈钢在25和50℃液-固两相流介质中的冲刷腐蚀速率分别为316L不锈钢的28倍和13倍以上,在25和50℃,J4不锈钢分别为选择性腐蚀和均匀腐蚀,而316L不锈钢均为轻微选择性腐蚀,Ni-P和Ni-Cu-P合金镀层均为均匀腐蚀。     

白云鄂博矿含氟烧结料对高铬铸铁篦条失效行为的影响

利用扫描电镜(SEM)观察白云鄂博矿烧结用失效高铬铸铁篦条的表面氧化膜形貌,进行成分能谱分析(EDS),测定氧化膜中氟含量,结合X射线衍射(XRD)对氧化膜进行物相分析,分析含氟烧结料用高铬铸铁篦条的失效机理.结果表明,在高温运行中,烧结料的F、S、Na、K等使篦条基材产生腐蚀,篦条腐蚀膜中结构疏松的Na2SO4、K2...     

镁合金金属型高铝矾土涂料阻燃性的研究

研究了镁合金金属型高铝矾土涂料的阻燃性。结果表明,合金液和高铝矾土容易在模具浇道处发生化学反应而导致涂料失效,反应产物为Mg2Al3和Mg2Si。阻燃剂可以减弱镁合金液与高铝矾土的反应,涂料的使用时间随着阻燃剂的增加而延长,试验中阻燃剂的最佳加入量为6%。     

黄柏提取物对Aβ1-42诱导的海马神经细胞的影响

目的：探讨黄柏提取物对Aβ1-42诱导的海马神经细胞的影响及分子机制。方法：分离培养海马神经细胞，将其分为对照组、模型组、模型+黄柏低、中、高浓度组、模型+si-NC组、模型+si-X失活的特异性转录本（XIST）组、模型+黄柏高浓度+pcDNA组、模型+黄柏高浓度+pcDNA-XIST组。MTT检测细胞存活率；流式细胞术检测细胞周期和细胞凋亡；Western blot法检测Cleaved-caspase3蛋白表达；RT-qPCR检测XIST表达水平。结果：模型组细胞存活率、S期细胞比例降低，G0-G1期细胞比例、XIST表达水平、凋亡率、Cleaved-caspase3表达水平升高（P<0.05）。不同浓度黄柏提取物处理及抑制XIST表达后，细胞存活率、S期细胞比例升高，G0-G1期细胞比例、XIST表达水平、凋亡率、Cleaved-caspase3表达水平降低（P<0.05）。过表达XIST减弱了黄柏提取物对Aβ1-42诱导的海马神经细胞增殖、凋亡的影响。 结论：黄柏提取物抑制Aβ1-42诱导的海马神经细胞凋亡，可能与下调XIST相关。     

Mechanism and prediction of failure of diamond films deposited on various substrates by HFCVD

Diamond films were deposited on the WC-Co cemented carbide and Si3N4 ceramic cutting tool substrates by hot-filament-assisted chemical vapour deposition. The adherence property of diamond films was estimated using the critical load (Pcr) in the indentation test. The adhesive strength of diamond films is related to the intermediate layer between the film and the substrate. Poor adhesion of diamond films to polished cemented carbide substrate is owing to the formation of graphite phase in the interface. The adhesion of diamond films deposited on acid etched cemented carbide substrate is improved, and the peeling-off of the films often happens in the loosen layer of WC particles where the cobalt element is nearly removed. The diamond films' adhesion to cemented carbide substrate whose surface layer is decarbonizated is strengthened dramatically because WC phase forms by reaction between the deposited carbon and tungsten in the surface layer of substrates during the deposition of diamond, which results in chemical combination in the film-substrate interface. The adhesion of diamond films to silicon nitride substrate is the firmest due to the formation of chemical combination of the SiC intermediate layer in the interfaces. In the piston-turning application, the diamond-coated Si3N4 ceramic and the cemented carbide cutting tools usually fail in the form of collapsing of edge and cracking or flaking respectively. They have no built-up edge(BUE) as long as coating is intact.As it wears through, BUE develops and the cutting force on it increases 1 - 3 times than that prior to failure. This can predict the failure of diamond-coated cutting tools.     

System Nd-Pd-O: Phase diagram and thermodynamic properties of oxides using a solid-state cell with advanced features

An isothermal section of the phase diagram for the system Nd-Pd-O at 1350 K has been established by equilibration of samples representing 13 different compositions and phase identification after quenching by optical and scanning electron microscopy, x-ray diffraction, and energy dispersive analysis of x-rays. The binary oxides PdO and NdO were not stable at 1350 K. Two ternary oxides Nd₄PdO₇ and Nd₂Pd₂O₅ were identified. Solid and liquid alloys, as well as the intermetallics NdPd₃ and NdPd₅, were found to be in equilibrium with Nd₂O₃. Based on the phase relations, three solidstate cells were designed to measure the Gibbs energies of formation of PdO and the two ternary oxides. An advanced version of the solid-state cell incorporating a buffer electrode was used for high-temperature thermodynamic measurements. The function of the buffer electrode, placed between reference and working electrodes, was to absorb the electrochemical flux of the mobile species through the solid electrolyte caused by trace electronic conductivity. The buffer electrode prevented polarization of the measuring electrode and ensured accurate data. Yttria-stabilized zirconia was used as the solid electrolyte and pure oxygen gas at a pressure of 0.1 MP a as the reference electrode. Electromotive force measurements, conducted from 950 to 1425 K, indicated the presence of a third ternary oxide Nd₂PdO₄, stable below 1135 (±10) K. Additional cells were designed to study this compound. The standard Gibbs energy of formation of PdO (†_f G ⁰) was measured from 775 to 1125 Kusing two separate cell designs against the primary reference standard for oxygen chemical potential. Based on the thermodynamic information, chemical potential diagrams for the system Nd-Pd-O were also developed.     

蒸发器盘管的腐蚀失效分析

采用化学元素分析、金属离子分析、X射线荧光分析，结果表明，腐蚀失效的盘管材质符合20^#钢的标准成分，蒸发器盘管局部失效穿孔，原因是铜离子与氧极化剂共同作用所致。     

Einfluß von Heißgasatmosphären auf Zeitstandverhalten und Gefüge einer mit Beschichtung versehenen Nickelbasislegierung

Influence of hot gas atmospheres on creep rupture behaviour and structure of coated nickel base alloys Al- and AlCr-coatings on nickel base super alloys show precipitations of a brittle phase after exposure to hot combustion gases. The precipitations are localized mainly in the transient area between coating and base material. Apart from this appearance cracks originating in the coating can be observed, propagating at right angle to the surface. Due to that failure in the coating no increase of the life time of coated materials can be observed compared with uncoated materials. This can be stated under the conditions of creep rupture tests in still hot air as well as in the stream of JP 4 combustion gases. Microanalytical investigations yield a close connection between the failure of the coating and the formation of needle shaped precipitations – mainly Cr-carbides – in the interface area of coating and base material. Auger analytical investigations and chemical analyses reveal distinct concentrations of nitrogen in the needle shaped area. The investigations revealed that the failure of the coating is mainly caused by the high content of nitrogen in the hot gases.     

吴茱萸碱体外抗肿瘤作用

目的:研究吴茱萸碱(evodiamine, Evo)的体外抑瘤谱, 并初步探讨其抗肿瘤的作用机制。方法:MTT 法测定Evo 对肿瘤细胞的生长抑制情况;采用光镜和电镜观察Evo 对人肺腺癌细胞SPCA 1形态的影响;流式细胞术检测Evo 对SPC-A 1细胞的抑制作用和细胞周期的影响。结果:Evo对SPC-A 1等10种肿瘤细胞有选择性的生长抑制作用, 5 μg/mL 的Evo 处理后, 细胞变圆, 体积变小, 分泌颗粒增多, 细胞折光性下降, 大部分细胞脱壁。透射电镜下可见细胞表面微绒毛消失、核染色质浓集、边聚, 核碎裂, 并可见凋亡小体;流式细胞仪检测Evo 作用后, G0G1期和S 期细胞减少, 大量细胞停滞在G₂/M 期, 凋亡细胞增多。结论:Evo 选择性的抑制肿瘤细胞的生长, 引起SPCA 1细胞典型的凋亡形态学改变并使细胞停滞于G₂/M 期, 其机制可能与诱导细胞凋亡和周期阻滞有关。     

胃瘤安不同组方对人胃癌SGC-7901增殖、细胞周期和凋亡的影响

目的: 通过观察胃瘤安(全方、三棱莪术方、无三棱莪术方)小、中、大3个剂量作用于人胃癌SGC-7901细胞24、48 h,探讨其对胃癌细胞的生长抑制作用及细胞周期和凋亡的影响,并对3种组方的胃瘤安进行比较。方法: 用RPMI1640 培养液对人胃癌细胞SGC-7901进行传代培养,采用MTT法检测胃瘤安不同组方对SGC-7901的生长抑制作用,采用流式细胞术检测胃瘤安不同组方对SGC-7901细胞凋亡及周期的影响。结果: 胃瘤安3种不同组方均可抑制SGC-7901细胞增殖;3种不同组方的胃瘤安均可促进正常的SGC-7901细胞凋亡,细胞周期分析提示胃瘤安(全方)、胃瘤安(无三棱、莪术)将细胞SGC-7901阻滞于S期,胃瘤安(三棱、莪术)将SGC-7901细胞阻滞于G₀ /G₁期,效应均呈浓度和时间依赖性。结论: 胃瘤安3种不同组方均能抑制人胃癌SGC-7901细胞的增殖,可将细胞阻滞在S和G₀/G₁期,其中以胃瘤安(全方)、胃瘤安(无三棱、莪术)效果最为明显。     

氨甲蝶呤对映体对肺癌A549细胞的生长抑制作用研究

摘要 目的 研究氨甲喋呤对映体对肺癌A549细胞的生长抑制作用。方法 倒置相差显微镜观察加入MTX对映体后细胞形态变化,应用MTT法检测MTX对映体对A549细胞的生长抑制作用,应用流式细胞术分析细胞周期分布及凋亡率的变化。 结果 倒置相差显微镜观察加入MTX对映体后细胞形态发生明显变化,MTT法检测表明两种MTX对映体抑制A549细胞的生长呈剂量与时间依赖性,L-（+）-MTX对A549细胞的抑制作用明显强于D-（-）-MTX。流式细胞检测发现两种MTX对映体药物对A549细胞的细胞周期和凋亡具有明显干扰作用。 结论 MTX对映体对A549细胞的作用明显具有手性差异,L-（+）-MTX对A549细胞的抑制作用明显强于D-（-）-MTX。关键词：氨甲蝶呤,对映体,A549细胞,增殖,凋亡     

Microstructure of Sm2Co17 magnets and its influence on coercivity

Sm(CobklFe0.197Cu0.049Zr0.026)7.5 magnet with Hci of 2105 kA/m and β18-200℃ of - 0.17 % /℃ was made by sintering processing. The magnet has uniform celluler structure. The cell interior is a rhombohedarl 2 : 17 phase,and the boundary is a hexagonal 1 : 5 phase. The average cell size is 93 nm and the cell boundary thickness is 20 nm.The cells are enriched in Fe, and the cell boundaries are enriched in Cu. More Cu-riched 1 : 5 cell boundary phase would be helpful to obtain a higher coercivity and lower temperature coefficient. White secondary phase mainly consisting of Sm can decrease the coercivity of the magnets, but the closely paralleled grooves can increase coercivity.     

吉祥草中甾体皂苷RCE-4对人宫颈癌Caski细胞Ras/Erk和p16/cyclinD1/CDK4通路的影响

目的: 研究吉祥草中甾体皂苷RCE-4影响Ras/Erk和p16/cyclinD1/CDK4信号通路促进Caski细胞凋亡的作用机制。方法: 体外培养人宫颈癌Caski细胞株，用RCE-4作为处理因素，MTT法检测细胞增殖活力；流式细胞术检测细胞周期分布；Real-time PCR检测p16、cyclinD1和CDK4 mRNA表达水平；Western blot检测Ras/Erk信号通路总蛋白和磷酸化蛋白表达水平。 结果: RCE-4呈剂量依赖性抑制Caski细胞增殖，其作用24 h的IC50值为12.33 μmol/L；升高G0/G1期细胞比例，降低S期细胞比例；抑制Ras、p-Raf、p-Mek1/2和p-Erk1/2蛋白表达，降低p-Raf/Raf、p-Mek1/2/Mek1/2和p-Erk1/2/Erk1/2比值，上调p16的mRNA表达，下调cyclinD1和CDK4的mRNA表达。 结论: RCE-4可抑制Caski细胞的增殖，诱导细胞在G0/G1期阻滞，其诱导作用与其抑制Ras/Erk和p16/cyclinD1/CDK4信号通路激活有关。     

某电厂汽轮机20Cr1Mo1VNbTiB钢汽门螺栓开裂失效分析

针对某电厂汽轮机用20Cr1Mo1VNbTiB钢高压调速汽门螺栓和中压联合汽门螺栓开裂原因进行了失效分析。分析结果表明:两螺栓样品的化学成分及硬度均符合相关标准要求。两螺栓样品的显微组织局部存在混晶现象,且组织中存在大量大块硬脆的第二相—MC相。组织中大块的硬脆MC相可以作为裂纹形核点,会增加裂纹萌生几率,加速材料裂纹扩展,增加材料开裂失效倾向。该析出相具有较高硬度和高稳定性,热处理难以将其消除,通常在冶炼过程中形成,应加强冶炼工艺管控,避免出现大量大块硬脆的MC相。