磁力轴承的原理,应用及发展动向

本文对磁力轴承的历史，原理作了介绍，并列举了此类轴承的独特优点。磁力轴承的应用范围很广，对支承技术来说是一场革命。文章指出了这方面的最新发展动向。     

基于钢球振动所产生的轴承噪声数学模型

利用声学理论中的振动球源建立了，由轴承钢球振动所产生的噪声数学模型，为研究滚动轴承的降噪减振提供了理论依据。同时根据现场的试验情况，对该数学模型进行了验证，其结果是可行的。     

磁力轴承

磁力轴承是国外80年代开发的新一代轴承。由于它是非接触式轴承。因而无磨损,不需机械维护,也勿需润滑,能实现高速运转。本文就这种轴承的结构原理、工作特点以及使用中的注意事项做了具体的叙述。图6幅。     

定子定位槽对径向磁力轴承影响的研究

针对有槽不对称的定子结构，利用有限元法对径向磁力轴承的电磁场进行了仿真与计算，并分析了计算结果。提出了几种结构方面的改进措施，为径向磁力轴承进一步的结构优化设计和控制系统的设计提供了依据。     

基于LabVIEW的磁力轴承轴心轨迹监测系统

建立了磁力轴承控制与监测平台的硬件系统,基于NI公司的图形化开发软件LabVIWE开发了磁力轴承轴心轨迹监测系统.该系统可以实时在线监测磁力轴承转子在高速旋转时的轴心轨迹和5个自由度方向的位移.     

飞轮储能用磁力轴承的发展研究

飞轮电池以高比能、环境友好等优点成为国内外研究热点。特别是在磁力轴承技术获得突破之后,飞轮储能效率与寿命都得到极大的提高。详细论述了飞轮储能系统中磁力轴承的发展历史与研究现状;对比分析了永磁轴承、电磁轴承和超导磁轴承的优缺点,指出被动磁力轴承对构建经济型飞轮电池的重要性;针对飞轮电池发展的实际需求提出了目前应重点研究的方向。     

圆弧齿同步带传动噪声理论分析与试验研究

以RU型圆弧齿同步带为研究对象，通过分析啮合冲击噪声和横向振动噪声的产生机制，得到转速为影响同步带传动噪声的主要原因。在同步带振动与噪声试验台上进行转速对同步带的振动与噪声影响规律的试验研究。利用激光位移传感器和声压传感器测量啮入点处同步带传动的振动和噪声信号，得到啮入点处的噪声和振动的时域分布曲线和频域分布曲线。从噪声和振动随转速变化规律曲线可知：随着转速的增加，噪声幅值逐渐增大，振动幅值逐渐减小。研究结果为同步带传动振动与噪声的控制提供了依据。     

汽车振动噪声测试的阶次跟踪方法

汽车振动和噪声是影响舒适性的主要因素，如何采用有效的技术手段测量分析汽车的振动、噪声，日益受到人们重视。本文应用PULSE多分析系统中的阶次跟踪分析方法，测试分析了车内司机座位处振动、噪声随发动机转速变化的关系，结果发现，对于试验车在测试工况下1．5倍发动机转速时，车内振动和噪声都有一个峰值。文中通过阶次分析，对发动机运转稳定性进行了测试。为降低车内噪声和振动响应提供了分析依据和参考。     

轴承套圈端面振动引起的噪声模型的确定

利用声学理论中的典型声源结构建立了由轴承套圈端面振动所产生的噪声数学模型，为研究滚动轴承的降噪减振提供了理论依据。同时根据现场的试验情况，对该噪声模型进行了验证，其结果是可行的。     

磁力轴承主轴的特性与分析

文章介绍了用于高速切削加工的磁力轴承主轴的结构、刚度曲线及其耐磨损、低功耗、高精度、高速度等主要特性,并通过与传统的各类轴承主轴的比较,揭示出磁力轴承主轴的优良特性及其广阔的使用前景.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Rheology Feature of Simple Metal Melt

The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.     

Microstructures and Mechanical Properties of a Newly Developed Austenitic Heat Resistant Steel

The effect of heat treatment on the microstructures and mechanical properties of a newly developed austenitic heat resistant steel(named as T8 alloy) for ultra-supercritical applications have been studied. Results show that the main phases in the alloy after solution treatment are γ and primary MX. Subsequent aging treatment causes the precipitation of M_(23)C_6 carbides along the grain boundaries and a small number of nanoscale MX inside the grains. In addition, with increasing the aging temperature and time, the morphology of M_(23)C_6 carbides changes from semi-continuous chain to continuous network.Compared with a commercial HR3C alloy, T8 alloy has comparable tensile strength, but higher stress rupture strength. The dominant cracking mechanism of the alloy during tensile test at room temperature is transgranular, while at high temperature, intergranular cracking becomes the main cracking mode, which may be caused by the precipitation of continuous M_(23)C_6 carbides along the grain boundaries. Typical intergranular cracking is the dominant cracking mode of the alloy at all stress rupture tests.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

The 15th Global Foundry Sourcing Conference 2014held in Qingdao China

Organized by Suppliers China Co., Ltd and co-organized by the National Technical Committee 54 on Foundry of Standardization Administration of China, the 15th Global Foundry Sourcing Conference 2014 （hereinafter referred to as FSC 2014） was successfully held on Sep. 23rd in Grand Regency Hotel, Qingdao. More than 500 delegates from home and abroad attended this conference, including over 130 purchasers from 20 countries and 380 domestic and foreign suppliers.     

Secondary Recrystallization Behaviors of Grain-Oriented 6.5 wt% Silicon Steel Sheets Produced by Rolling and Nitriding Processes

By rolling and nitriding processes, 0.23- to 0.3-mm-thick grain-oriented 6.5 wt% silicon steel sheets were produced. The core losses of grain-oriented 6.5 wt% silicon steel at frequencies ranging from 400 Hz to 20 k Hz were lower than that of the grain-oriented 3 wt% silicon steel with the same thickness by 16.6–35.8%. The secondary recrystallization behavior was investigated by scanning electron microscopy, energy-dispersive spectroscopy, and electron backscattered diffraction. The results show that the secondary recrystallization in high-silicon steel sheets develops more completely as the nitrogen content increases after nitriding, secondary recrystallized grain sizes become larger, and the sharpness of Goss texture increases. Because more {110}116 grains in the subsurface and the central layer of the sheets have a lot of 20°–45° high-energy boundaries in addition to Goss grains, {110}116 can be the main component through selective growth during secondary recrystallization when the inhibitor quantity is not enough and inhibitor intensity is weaker. The increases in nitrogen content can increase the inhibitor intensity and hinder abnormal growth of a mount of {110}116 grains and therefore enhance the sharpness of Goss texture.     

Laser Cladded TiCN Coatings on the Surface of Titanium

Laser cladded coatings of TiCN were produced on the surface of titanium. To obtain the optimal techniques, several conditions were tested by varying the laser scanning rate. The choice of shielding gas was also studied. The cladded coatings were then evaluated from the surface mechanics point of view based on their microhardness. The microstructure of some interesting samples was investigated by optical micrographs (OM). The results showed that under the condition of fixed pulse frequency and pulse width, the laser scanning rate and the shielding gas are the main factors influencing the components of coatings. TiCN coatings were decompounded and oxidized during the cladding process in the condition of no shielding gas of N2. X-ray diffraction results indicated that the composite coatings composed of TiCN, TiC, Ti2N, and TiO2 were produced using appropriate techniques. The results indicated that the best condition in terms of the surface microhardness is obtained when the scanning rate is 1.5mm / s, the pulse frequency is 15Hz, the pulse width is 3.0ms, and N2 is chosen as the shielding gas. The microhardness of the composite coatings is about 1331kg · mm - 2, which is about 4 times that of the substrate. The optical micrographs indicated that the cladding zone is made up of TiCN, TiO2, and some interdendritic Ti, but the diffusion zone mainly consists of the dendrites phase, and the cladded depth is about 80?滋m, which is more than 2 times that of the laser nitrided sample. There were no microcracks or air bubbles in the cladded sample, which was cladded using the above optimal techniques.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

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正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis