退火温度对Fe74Al4Sn2P10C2B4Si4非晶磁粉芯性能的影响

对Fe74Al4Sn2P10C2B4Si4非晶磁粉芯退火温度进行了研究,发现采用60min的退火时间,随着退火温度的变化,磁粉芯电感及品质因数在不同温度阶段表现出各自的特性.从室温至300℃之间,磁粉芯性能随着温度的升高缓慢改善,在此区间磁粉芯磁导率提高约47%;当温度在300～400℃之间,磁粉芯性能随着退火温度的升高显著改善,在此区间磁粉芯磁导率提高76%;当退火温度在400～440℃之间,磁粉芯磁导率及1MHz以下品质因数达到最大值;当退火温度接近初始晶化温度468℃时,磁粉芯在1MHz以上具有较好的综合性能.     

金属磁粉芯绝缘包覆工艺的发展研究

金属磁粉芯是以金属软磁粉末为原料,经绝缘包覆、加压成型和热处理等工艺处理后制备的软磁复合材料,其中绝缘包覆工艺是制备金属磁粉芯的关键技术。通过介绍金属磁粉芯有机、无机、有机-无机复合包覆工艺,对比磷酸、氧化物、铁氧体等包覆工艺对磁粉芯性能的影响,展望了包覆工艺技术的发展方向,为磁粉芯包覆工艺的研究和发展提供参考。     

退火工艺对Fe-Si-Ni-Al-Ti磁粉芯性能的影响

采用气雾化技术并结合模压成形方法制备Fe-3Si-2Ni-0.5Al-2Ti磁粉芯,通过热分析仪、X射线衍射仪、电子探针以及软磁交流测量装置表征和分析了绝缘包覆剂的热稳定性、磁粉芯的相组成、碳氧含量及磁性能,并探讨退火温度、升温速率、保温时间对磁粉芯性能的影响。结果表明:随退火温度由180℃升高至280℃,磁粉芯的矫顽力下降,磁导率增大,损耗降低;但进一步升高至380℃时,磁粉芯性能下降。升温速率过快(3℃/min)或过慢(1℃/min),均不利于磁粉芯性能的提高,较佳升温速率为2℃/min。当保温时间由60 min延长至90 min时,磁粉芯的矫顽力下降、有效磁导率增大、损耗降低;但进一步延长保温时间(150 min)对磁粉芯性能的改善并不明显。     

粉末冶金工艺对纯铁磁粉芯力学性能的影响

在铁粉中添加耐热型树脂粘结剂,通过球磨使铁粉颗粒表面包覆一层均匀的绝缘膜,再利用模压和热处理制备纯铁磁粉芯,研究球磨工艺对铁粉形貌和粒径的影响,分析压制压力、热处理工艺以及粘结剂含量对纯铁磁粉芯力学性能的影响。结果表明,在转速400 r/min、球料质量比15:1、球磨时间10 h的条件下可将粉末研磨成适合于制备铁磁粉芯的鳞片状铁粉,平均粒径为100μm;在粘结剂总含量2.65%、压制压力1 200 MPa、压坯在N2保护气氛下500℃保温1 h条件下,获得的磁粉芯力学性能最佳,抗压强度达到502.98 MPa。     

粘结剂含量对粘结NdFeB磁体磁性能和抗压强度的影响

用环氧树脂粘结剂制备了NdFeB粘结磁体,探讨了粘结剂含量对粘结磁体磁性能和抗压强度的影响规律及机理.当粘结剂含量为1%(质量分数,下同)时,磁粉不能完全被包覆、粘结,磁体密度、磁性能和抗压强度低;当粘结剂含量为5%时,粘结剂体积分数大,稀释了磁体的磁性能,多余的粘结剂也使磁体抗压强度降低.粘结剂含量为2.5%时磁体具有较佳的性能:剩磁Br=0.616T;内禀矫顽力Hcj=784kA/m;最大磁能积(BH)m=58kJ/m3;抗压强度为236MPa.     

退火温度对Fe74A14Sn2P10C2B4Si4非晶磁粉芯性能的影响

对Fe74A14Sn2P10C2B4Si。非晶磁粉芯退火温度进行了研究，发现采用60min的退火时间，随着退火温度的变化，磁粉芯电感及品质因数在不同温度阶段表现出各自的特性。从室温至300℃之间，磁粉芯件能随着温度的升高缓慢改善，在此区间磁粉芯磁导串提高约47％；当温度在300～400℃之间，磁粉芯性能随着遐火温度的升高显著改善，在此区间磁粉芯磁导率提高76％；当退火温度在400～44012之间，磁粉芯磁导率及1M比以下品质因数达到最大值；当退火温度接近初始品化温度468℃时，磁粉芯住1MHz以上具有较好的综合性能。     

高性能Fe-Si软磁粉芯的制备及性能研究

以Fe-6.5Si粉末为基粉、多组分无机氧化物作为粘结剂,通过温压成形、热处理制得Fe-Si软磁粉芯。分别使用扫描电子显微镜、振动磁强计对样品的密度、微观形貌以及磁性能等进行了测试分析。结果表明:粘结剂的含量、温压压力、温压温度对Fe-Si软磁粉芯的性能都会产生影响,在压制温度150℃、压制压力为900MPa时,粘结剂含量为1.5%(质量分数)的Fe-Si生坯密度可以达到6.34g/cm3,经过720℃氩气气氛下热处理后密度可达到6.58g/cm3,饱和磁感应强度为1.26T,矫顽力为0.81 kA·m-1。     

轧膜成形制备W-Cu层状功能梯度材料及其性能研究

以W粉和电解Cu粉为原料,聚乙烯醇缩丁醛(PVB)为粘结剂,通过有机基轧膜工艺制备出3种组成的单层生坯(Cu质量分数分别为25%、50%、75%),再叠层共轧,制备出了具有不同粘结剂含量的W-Cu层状梯度材料生坯,之后在H2气氛中烧结,获得了W-Cu层状梯度材料,考察了粘结剂含量与制备工艺条件对材料显微组织和性能的影响。结果表明,通过单层轧制、叠层共轧共烧可以制得层状梯度W-Cu复合材料;粘结剂含量对W-Cu层状梯度材料的致密度和性能有着明显的影响。当粘结剂质量分数为6%时,轧膜坯有较好的成形性,且成形坯的孔隙率较低;所得多层生坯经1 150℃烧结后相对密度达93.11%;所得梯度W-Cu材料有良好的物理、力学性能。     

非晶Fe74Al4Sn2P10C2B4Si4与Fe17Ni81Mo2 复合磁粉芯的性能研究

采用水雾化方法分别制备Fe74Al4Sn2P10C2B4Si4非晶粉末和Fe17Ni81Mo2粉末,再将两种粉末混合制备复合磁粉芯,对复合磁粉芯的性能进行了研究.通过混合可以得到品质因数较高、电感频率特性较好的复合磁粉芯,并且随着混合比例的变化,可以获得一系列具有连续磁性能的磁粉芯.当非晶粉末比例在50%(质量分数,下同)以下,随着非晶粉末质量百分比的增大,复合磁粉芯性能的变化速度较快;当非晶粉末比例达到50%以上,随着非晶粉末质量百分比的增大,复合磁粉芯性能的变化速度较慢.分析认为,复合磁粉芯性能的变化规律与Fe17Ni81Mo2粉末及非晶粉末特性及其在磁粉芯中的作用有关.     

钛注射成形用催化脱脂型喂料的制备与性能研究

针对钛粉末注射成形用催化脱脂型喂料,设计和优化了粘结剂的成分配比及粉末装载量,研究了催化脱脂型粘结剂组元不同配比喂料的流变性能,分析了时间和温度对粘结剂的脱除效率的影响,考察了钛烧结件致密度和碳氧含量的变化。实验结果表明:粘结剂各组元配比为m(POM)∶m(HDPE)∶m(EVA)∶m(SA)∶m(M)=86∶5∶5∶2∶2,=44%时,钛喂料的流变性能最好,其综合模塑性指数为2.25 m2/N·s·K,SEM结果显示钛粉末和粘结剂分布均匀。在120℃催化脱脂6小时,脱除率为78%。钛件经1 180℃真空烧结,致密度为94.8%,其C、O含量分别为0.24%和0.70%。     

超细WC-Co硬质合金的磁性能和金相分析

介绍了超细WC-Co硬质合金的磁性能和金相,对它们之间的关系和作用进行了比较分析,认为磁性能和金相是超细WC-Co硬质合金质量控制的重要检测方法。     

五氯化钼

简单介绍了五氯化钼的应用、化学性能和物理性能.     

LF炉精炼渣冶金性能的研究现状

主要从精炼渣组分对其发泡性能和脱硫性能的影响二个方面综述了精炼渣的研究现状，展望了精炼渣的发展前景和方向，为今后精炼渣的研究和使用提供依据和参考。     

V含量对TaVCN复合膜微结构、力学性能和摩擦磨损性能的影响

采用多靶磁控溅射技术,制备一系列不同V含量的TaVCN复合膜。利用X射线衍射仪、纳米压痕仪和高温摩擦磨损仪研究该复合膜的微结构、力学性能和摩擦磨损性能。结果表明, TaVCN复合膜为面心立方和底心斜方的双相结构。随V含量增加,复合膜的硬度先升高后降低,当V原子分数为26.85%时,复合膜的硬度达到最大值,为31.7 GPa。室温下随V含量增加,复合膜的摩擦因数和磨损率均先减小后增大,V原子分数为32.60%时,摩擦因数达到最小值,为0.213;V原子分数为26.85%时,磨损率达到最小值,为2.1×10?7 mm2/N。随温度升高,复合膜的摩擦因数逐渐减小,磨损率逐渐增大。并对不同温度下 TaVCN 和 TaCN 复合膜的摩擦磨损性能进行了讨论。     

Review of the historical, empirical, and theoretical status of the von Restorff phenomenon.

The major purpose of the review was to examine theoretical and empirical properties of the von Restorff phenomenon. A selection of studies that preceded the von Restorff article demonstrated that isolating an item by making it more vivid than the rest of the list yielded a positive influence on learning that item. Subsequent studies in a variety of contexts have been quite consistent in confirming that isolation facilitates learning of the isolated item. This review attempts to indicate some of the specific features and influences of the von Restorff effect. The final section of the article presents theoretical discussions and suggested attempts to explain the isolation effect. (2 p. ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nd-doped ZnO as a multifunctional nanomaterial

Chemically synthesised ZnO and Nd-doped ZnO nanoparticles were investigated for structural, optical, magnetic properties along with photocatalytic activity. Transmission electron microscopy measurement was performed on the undoped and doped ZnO nanoparticles. Compared to the undoped ZnO, Nd-doped ZnO nanoparticles showed enhanced photoluminescent and ferromagnetic properties. The Nd-doped ZnO nanoparticles also showed improved photocatalytic properties compared with the undoped ZnO nanoparticles. Furthermore, the effect of UV light irradiation was studied with thermoluminescence (TL) and photoluminescence (PL) measurement techniques. It was found that in case of Nd-doped ZnO nanoparticles TL intensity increased while the green emission in PL spectra decreased with UV-light irradiation. This was attributed to the production of more surface defects on UV irradiation on Nd-doping.     

Effect of Nd2O3 doping on the electrical properties of Ba0.96Ca0.04Ti0.90Sn0.10O3 ceramics

The Ba_(0.96)Ca_(0.04)Ti_(0.90)Sn_(0.10)O_3-xNd_2 O_3(x = 0-0.08%) ceramics were prepared via traditional solid-state sintering method. The influences of Nd3+ substitution on the phase structure, dielectric properties,piezoelectric and ferroelectric properties of the ceramics were investigated. All the samples possess pure BaTiO_3-type perovskite structure. MPB with orthorhombic and tetragonal phase coexist at around x = 0.03-0.04. Nd~(3+) doping decreases both Tc and T_(O-T) to lower temperature. All the samples exhibit an intermediate state with the coexistence of ferroelectric and diffuse relaxor ferroelectric behavior with the addition of Nd~(3+). The electric properties of the ceramics were optimized at x = 0.03 with d33, K_p, ε_r and P_r values of 545 pC/N, 51.9%, 24,412 and 10.74 μC/cm~2.     

30万,60万千瓦汽轮机紧固件用高温合金的研究

本文研究了GH26合金成分中最佳碳钛含量,抗应力松弛性能、抗蠕变性能和抗应力腐蚀性能,合金组织和在使用温度下长时时效后组织稳定性。合金制作的紧固螺栓和汽封弹簧片等部件已用于国产首台引进60万千瓦汽轮机组上。     

Modeling the Mechanical Behavior of Lung Tissue at the Microlevel

This paper is concerned with the development of a computational model of pulmonary alveoli against the background of ventilator-induced lung injuries. In order to quantify mechanical stimulation of alveolar tissue during artificial respiration, a detailed constitutive model of alveolar septa and an approach to consider interfacial phenomena is needed. For that purpose, a polyconvex hyperelastic material model formerly developed for arteries is adopted for pulmonary alveoli. Information about tissue morphology is inherently integrated into the constitutive model, therefore, establishing a connection between structure and function of the different septal constituents. Structural and interfacial dynamics are directly coupled at the alveolar surface. In order to take into account the complex behavior of surface active agents covering alveoli, a constitutive model considering dynamical changes of surface energy is employed.     

Influence of alloying elements and grain refiner on microstructure,mechanical and wear properties of Mg-Al-Zn alloys

In the present investigation, the effects of alloying elements (Sn, Pb) and grain refiner (Ag, Zr) on microstructure, mechanical and wear properties of as-cast Mg-Al-Zn alloys were studied. The alloys were prepared through melting-casting route under a protective atmosphere and cast into a permanent mould. The microstructure of the base alloy consisted of α-Mg, Mg₁₇Al₁₂ continuous eutectic phase at the grain boundary and Mg-Zn phase was distributed within the grains. Addition of Sn and Pb suppressed the formation of continuous Mg₁₇Al₁₂ eutectic phase and formed Pb enriched Mg₂Sn precipitates at the grain boundary as well as inside the grain. The Ag and Zr addition to Mg-Al-Zn-Sn-Pb alloy suppressed the Mg₁₇Al₁₂ phase formation and refined the grains leading to improve mechanical properties. Addition of Sn, Pb and grain refiner (Ag, Zr) significantly enhanced the tensile strength and elongation but reduced hardness. The Ag addition imparted best tensile properties, where ultimate tensile strength (UTS) and elongation are 205?MPa and 8.0%, respectively. The fracture surfaces were examined under SEM which revealed cleavage facets and dimple formation. Therefore, the cleavage fracture and dimple rupture were considered as the dominant fracture mechanisms for developed Mg alloys. The cumulative volume loss of Mg alloys increased with sliding distance and applied load. The coefficient of friction decreased with sliding distance. The microscopic observation, analysis of the wear surface and coefficient of friction revealed that the wear mechanism of developed Mg alloys changes from abrasion oxidation to delamination wear.