Effect of Post Annealing on the Microstructure and Magnetic Properties of NdFeB/α-Fe/NdFeB Thin Films

A series of nanocomposite thin films, composed of Nd2Fe14B and α-Fe, has been prepared by DC-magnetron sputtering combined ion beam sputtering onto Si (100) substrates. The effects of post annealing on the microstructure and magnetic properties of [NdFeB/α-Fe/NdFeB]-type thin films have been investigated. The X-ray diffraction (XRD) study showed that annealing of the films for 30min at temperatures 550,600,650,700℃ resulted in the appearance of diffraction peaks, characteristic for Nd2Fe14B tetragonal structure, α-Fe and Nd2O3 phases. The investigation using the Vibrating Sample Magnetometer (VSM) with a maximum applied field of 2 T indicated that with the increase of the annealing temperature, the magnetic properties of the multilayer films were improved and reached peak value at 650℃ (Hci=41.72kA·m-1, Mr/Ms=0.4, (BH)max=30.35kJ·m-3), after which the magnetic properties were decreased greatly. Along with the increase of the thickness of α-Fe layer from Tα-Fe16nm, the coercivity Hci, saturation magnetization Ms, and remanence ratio Mr/Ms all declined. As the Atomic Force Microscope (AFM) indicated, after being annealed at 650℃ for 30min, the sample was showed fine surface morphology with grain size 60nm≤dα-Fe≤80nm and 100nm≤dNdFeB≤150nm.     

喷气客机涡轮风扇发动机的振动诊断与改进

通过动态分析和现场测试对一喷气客机的发动机振动作出诊断，发现涡轮叶轮的变柔导致其极转动惯量显著下降，因而改变发动机的动态特性，使其临界转速接近飞机的巡航转速，产生不应有的振动和噪声。文章提出了具体改进方案，已为研制单位采用。     

电脉冲快速退火对铁基非晶合金性能的影响

采用大电流交流脉冲对非晶Ｆｅ７８Ｂ１３Ｓｉ９合金进行了去应力退火。初步探讨了电脉冲加热对加热速率和该合金内应力释放、退火脆化以及最终软磁性影响的基本规律。结果表明：电脉冲加热可以得到远高于常规退火的加热速率，选择合适工艺参数可使非晶合金内应力释放９０％，软磁性（Ｈ＿ｃ和Ｂ＿ｓ）达常规退火后的９５％以上，与此同时使合金的延性（断裂应变ε＿ｆ）维持在０．９以上，从而有望实现非晶合金磁性与延性的合理配合。     

三脉冲不等强度激光片光源的研制及应用

本文报道了最近研制成功三脉冲不等强度调Q红宝石激光片光源系统.利用小颗粒对片光源90°方向的散射光对动态颗粒场进行高速摄影,从底片中能够精确直观地判断微小颗粒的瞬时分布、运动方向、速度和加速度情况.     

百色盆地林蓬浅层稠油油藏热采开发的可行性研究

百色盆地林蓬油藏为一浅、薄、低产、低渗的普通稠油构造油藏。通过对油藏特征、原油热物性、热采数值模拟初步分析及热米开发经济效益的初步评价，认为林蓬油藏利用我国现有的热采技术投入开发具有可行性，并提出了具体实施方案和工作意见．     

Current ISI and monitoring technologies in European energy industries

This paper reviews available information on the state of practice of inservice material property monitoring performed in European energy industries. Current practice includes a range of standard nondestructive testing and monitoring methods, improved remote sampling and surveillance specimen testing, and new monitoring techniques which are emerging from ongoing development programs. These new technologies include ultrasonic, positron annihilation, neutron diffraction, and magnetic techniques.     

Accurate Depth of Field Simulation in Real Time

We present a new post processing method of simulating depth of field based on accurate calculations of circles of confusion. Compared to previous work, our method derives actual scene depth information directly from the existing depth buffer, requires no specialized rendering passes, and allows easy integration into existing rendering applications. Our implementation uses an adaptive, two‐pass filter, producing a high quality depth of field effect that can be executed entirely on the GPU, taking advantage of the parallelism of modern graphics cards and permitting real time performance when applied to large numbers of pixels.     

A Survey on the Numerics and Computations for the Landau-Lifshitz Equation of Micromagnetism

The Landau-Lifshitz (LL)equation of micromagnetism governs rich variety of the evolution of magnetization patterns in ferromagnetic media. This is due to the complexity of physical quantities appearing in the LL equation. This complexity causes also an interesting mathematical properties of the LL equation: nonlocal character for some quantities,nonconvex side-constraints, strongly nonlinear terms. These effects influence also the numerical approximations. In this work, recent developments on the approximation of weak solutions, together with the overview of well-known methods for strong solutions,are addressed. Author is supported by the Fund for Scientific Research - Flanders FWO (Belgium).     

升平气田产能预测方法

依据升平气田的试井资料，建立了气井产能与压差之间的二次项产能方程。运用此方程可以预测升平气田的单井产能，并且建立了压差平方与kh值相关的气田综合产能方程。当求得气田的平均kh值后，利用该方法可以求得气田的平均产能或生产压差。