低压化成铝箔磷酸处理的研究与应用

对铝电解电容器低压化成箔作表面磷酸处理,研究了磷酸浓度、温度和作用时间对铝箔比容和耐水合升压时间的影响,优化最佳工艺条件,明显提高了铝电解电容器低压化成箔的性能,并应用于生产线.     

Low sputter damage of metal single crystalline surfaces investigated with medium energy ion scattering spectroscopy

It was observed clearly that the sputter damage due to Ar⁺ ion bombardment on metal single crystalline surfaces is extremely low and the local surface atomic structure is preserved, which is totally different from semiconductor single crystalline surfaces. Medium energy ion scattering spectroscopy (MEIS) shows that there is little irradiation damage on the metal single crystalline surfaces such as Pt(111), Pt(100), and Cu(111), in contrast to the semiconductor Si(100) surfaces, for the ion energy of 3–7 keV even above 10¹⁶–10¹⁷ ions/cm² ion doses at room temperature. However, low energy electron diffraction (LEED) spots became blurred after bombardment. Transmission Electron Microscopy (TEM) studies of a Pt polycrystalline thin film showed formation of dislocations after sputtering. Complementary MEIS, LEED and TEM data show that on sputtered single-crystal metal surfaces, metal atoms recrystallize at room temperature after each ion impact. After repeated ion impacts, local defects accumulate to degrade long range orders.     

铝箔力学性能的实验研究

铝箔已被广泛应用于电子工业,现又被用作锂电池正极集流体,因而对于铝箔的力学性能要求也在不断提高。通过表征和研究铝箔的力学性能(弹性模量、屈服强度、断裂强度等),能够为铝箔相关技术的可靠性研究提供必要的数据支持和理论指导,从而使铝箔得到合理和可靠的使用。本文运用微拉伸、纳米压痕和动态力学分析(DMA)实验,分别研究了不同厚度的H18态和O态铝箔的力学性能。结果表明两者的弹性模量均约为30GPa,仅为块材的一半;H18态铝箔材料的断裂强度要明显强于块材,而O态铝箔材料的断裂强度则明显小于块材;此外,H18态铝箔材料的屈服强度明显大于块材,O态铝箔材料的屈服强度与块材相仿。并且,随着厚度的增加,H18态铝箔材料的延伸率显著增大,但是仍远小于块材。通过扫描电子显微镜(SEM)对铝箔材料断裂形貌进行微观分析,发现铝箔的拉伸断裂方式为脆性断裂。     

涂碳铝箔对磷酸铁锂电池性能影响研究

本文研究了使用涂碳铝箔作为正极集流体磷酸铁锂电池的性能。研究对比了使用普通铝箔和涂层铝箔的10 Ah软包磷酸铁锂电池的主要性能。研究表明：使用涂层铝箔不但可以提高磷酸铁锂材料的粘结性,而且使用导电涂层可以有效降低正极材料和集流体的接触内阻,从而减小电池内阻,提高电池倍率性能。与使用普通铝箔作为集流体相比,通过使用涂碳铝箔可以使得电池的内阻降低65%左右,但是,磷酸铁锂正极材料的克容量却偏低约5~10 mAh·g^-1,首次效率也偏低4%左右;在快速放电15C倍率下,使用涂碳铝箔的电芯比使用普通铝箔容量提高约15%左右,10C放电倍率下,平台增加0.3~0.4 V;使用涂碳铝箔电芯的常温自放电率较高,但容量恢复率也较高;550周循环下,使用涂碳铝箔可以使得电池的循环性能提高约1%。而在电池低温性能方面,使用涂碳铝箔对低温性能并无改善。     

Folded tandem ion accelerator facility at trombay

The folded tandem ion accelerator (FOTIA) project at BARC has been commissioned. The analysed carbon beams of 40 nA(3⁺) and 25 nA(4⁺), at terminal voltage of 2.5 MV with N₂ + CO₂ as insulating gas, were obtained. The beams were characterized by performing the Rutherford back scattering (RBS) on gold, tin and iron targets. The beam energy of 12.5 MeV for ¹²C⁴⁺ was consistent with the terminal voltage of 2.5 MV. The N₂ + CO₂ mixture is being replaced by SF₆ gas in order to achieve 6 MV on the terminal. In this paper, some of the salient features of the FOTIA and its present status are discussed.     

Modeling the capacity of a novel flow-energy harvester

The performance of a new type of flow energy harvester based on oscillating foils is investigated through numerical modeling by using two methods, a 2D thin-plate model and a 3D nonlinear boundary-element model. The fluid–structure interaction problem involved in the dynamics of a heaving/pitching foil coupled with an actuation/energy harvesting system in this device is examined. The 2D analysis allows us to simulate dynamics of the flapping-foil system over a large range of parameters and to identify areas of special interests (e.g., high energy output or high efficiency). In the vicinity of these areas the 3D model can accurately predict the performance of the system. By examining the power extraction capacity and efficiency of the system at various geometric, mechanical, and kinematic parameters, the optimal performance of the system is determined. In addition, the performance is found to be enhanced by the presence of a solid ground, as well as the thickness of the foil (at certain frequencies).     

三级GEM气体探测器性能的实验研究

GEM探测器是一种新型微型气体探测器(Micro-Pattern Gas Detector), 在粒子物理实验及低能X射线成像系统中有着较大的应用前景. 文章研制了一种适用于低能X射线成像和带电粒子径迹测量的三级GEM气体探测器. 使用放射源⁵⁵Fe对其气体放大特性、电荷传输效率及能量分辨本领等性能进行了实验研究, 重点研究了传输区电场对气体有效增益和能量分辨本领的影响. 实验结果表明, 三级GEM探测器的暗电流和噪声较小, 有效增益能够达到10⁵以上并稳定地工作, 对5.9keV的X射线能量分辨率可达24%, 传输区电场强度大于3000V/(cm.atm)时, 能量分辨率基本稳定在30%左右.     

A simple post-accelerator foil stripper assembly for atomic collision experiments

A multiple foil holder for use in ultra high vacuum (UHV) environment as a post accelerator ion stripper has been designed and fabricated. It is used to produce beams of an ion in different charge states at a given energy from a 14 MV pelletron accelerator. These ions are required in several types of atomic collision experiments. The assembly is tested with³²S ions at various energies.     

The texture of electrodeposited iron foils

The texture of electro-deposited iron foils was measured. It was observed that a {110} fibre texture developed in these deposited iron foils. When a sufficiently strong magnetic field was applied along the deposit layer during the deposition process, a {110}〈001〉 texture developed from the initially formed {110} fibre texture, with the 〈001〉 axis parallel to the magnetic field. An attempt has been made to explain the texture development and the effect of the applied magnetic field in the deposition process.