Pitting corrosion resistance of La added 316L stainless steel in simulated body fluids

Lanthanum (La), a rare earth element with anticoagulative and antiphlogistic function, was added into the medical grade 316L stainless steel in order to improve its biocompatibility. The corrosion resistance of the La added 316L steel in two different simulated body fluids, simulated blood plasma and Hank's solution, was evaluated. The result showed that the addition of La in the steel could largely affect the corrosion behavior of the steel. The steel with 0.01% La showed the widest passive region and the best resistance to pitting attack, within the addition range of La from 0.01% to 0.08%. The corrosion resistance improvement of La added 316L stainless steel is probably due to the effect of La on the purification of the steel, the modification of inclusions, and the passive film formation in the simulated body fluids.     

Facile synthesis of ordered nanocrystalline alumina thin films with tunable mesopore structures

Mesoporous alumina layers have attracted attention for their potential use in ultrafiltration of salts, as a heterogeneous catalyst support, an adsorbent in environmental cleanup, and in petroleum refinement. The ability to control the fast hydrolysis rate of the inorganic precursors using simple and inexpensive routes is important for that potential to be realized. Herein, we introduce a novel and facile route to synthesize mesoporous alumina thin films from the combination of inexpensive and commercially available copolymer with aluminum chloride or nitrate (salts) in an EtOH–surfactant–NH₃ · H₂O–salts (EsNs) system through the evaporation-induced self-assembly (EISA) method. Mesoporous alumina layers obtained utilizing the EsNs system have ordered and tunable pore structures. The ability to easily control the mesophases of the alumina layers within a short time provides distinct advantages over previously reported synthesis procedures. Most importantly, we demonstrate that the binding of surfactant and NH₃ · H₂O for the formation of hydrogen bond between them in the EsNs system controls the fast hydrolysis rate of the inorganic species. This allows for the synthesis of nanocrystalline alumina layers via the aluminum oxo-clusters’ assembly with the surfactant. Such simple route may be applied in the synthesis of other non-silica mesostructured oxides.     

利用射线路径反演层状介质速度的方法

本文根据欧拉方程对于连续层状介质进行了方程推导，得出一个波传播的射线路径公式，利用中 公式导出了ＶＳＰ资料处理中的速度反演公式。     

电流变体特性及电流变体应用器件的进展

本文详细评述了电流变体(ERF)材料的组成、工作机理及其流变力学性能,提出以Bingham塑性体来近似描述电流变体的流变特性,综述了电流变体在智能材料、汽车离合器、液压阀门等器件中的应用,给出了含电流变体的双层智能复合材料梁单层、双层加电状态对其振动特性的影响,设计了含电流变体的主动控制式减振器,并对其在外加电场作用下的减振性能进行了评价。     

高炉冲渣水在采暖工程中的应用

随着我国经济的迅速发展,能源消耗不断增加,节约能源、降低能源消耗势在必行,余热利用是节约能源的一个重要环节,冶金行业高炉冲渣水作为采暖热媒可以节约大量能源。     

电力系统动态过程的柔性自校正仿真方法

电力系统动态过程仿真的效率和数值稳定性常常受到刚性的困扰。通过对非线性动态系统刚性特征的分析和再思考指出：刚性时空分布的局部性为柔性化提供了基础。其次，文中提出了自适应柔性分组策略和具有自校正积分措施的变量组协调策略。通过对变量组别划分、相对步长因子调整、最小积分步长调整3种自适应策略的统一处理,可以动态地控制变量组别的变化和积分步长的调整，在保证精度的前提下放开了较慢变量的步长，避免了传统方法所有变量采用相同步长进行积分导致计算效率低下的缺陷，克服了现有变量分组方法难以做到同时自适应调整多个控制参量的不足，使计算效率得到了显著提高。     

双马来酰亚胺基体树脂的改性研究

本文报道用改性物B改善双马来酰亚胺/二胺预聚物溶解性的实验研究.结果表明,改性后的双马来酰亚胺/二胺基体树脂在低沸点、低毒性溶剂如丙酮中具有良好的溶解性,并且有足够的均相期,为湿法制作预浸料创造了有利条件.同时对树脂的固化反应、耐热稳定性及其复合材料在高温条件下(150℃、200℃)的层间剪切性能进行了研究.     

反射补偿式光纤位移传感器的理论分析

概述了反射式光纤传感器的发展。讨论了这类光纤传感器理论分析中所采用的纤端出射光场光强径向均匀分布的假设。给出了纤端出射场的光通量分布函数,并以全光路补偿反射式光纤探头为例,建立了补偿机理的理论分析方法,给出了传感特性调制函数的解析表达式。最后,简要分析了这类光纤传感器的温度稳定性问题。     

Distributed multi-join query processing in data grids

Query processing in data grids is a difficult issue due to the heterogeneous, unpredictable and volatile behaviors of the grid resources. Applying join operations on remote relations in data grids is a unique and interesting problem. However, to the best of our knowledge, little is done to date on multi-join query processing in data grids. An approach for processing multi-join queries is proposed in this paper. Firstly, a relation-reduction algorithm for reducing the sizes of operand relations is presented in order to minimize data transmission cost among grid nodes. Then, a method for scheduling computer nodes in data grids is devised to parallel process multi-join queries. Thirdly, an innovative method is developed to efficiently execute join operations in a pipeline fashion. Finally, a complete algorithm for processing multi-join queries is given. Analytical and experimental results show the effectiveness and efficiency of the proposed approach.     

Effects of P2O5 and sintering temperature on microstructure and mechanical properties of lithium disilicate glass-ceramics

This paper investigates the effect of P₂O₅ content and sintering temperature on the microstructure of lithium disilicate glass-ceramics and analyzes the relation between microstructure and mechanical properties. Specimens were prepared by hot-pressing technology, adding 1.0–4.0 mol% P₂O₅ (G1P, G2P, G3P and G4P). Lithium disilicate (Li₂Si₂O₅), lithium metasilicate (Li₂SiO₃) and lithium orthophosphate (Li₃PO₄) crystalline phases were detected. The morphology of Li₂Si₂O₅ crystals transformed from rod-shaped to needle-like and the mechanical properties inevitably decreased. Additionally, G1P and G2P were prepared by hot-pressing technology with sintering temperatures ranging 780–840 °C. The results showed that sintering temperature had no significant effect on the crystalline phases and microstructure. The optimal mechanical performances (flexural strength 290 MPa; fracture toughness 3.3 MPa m^1/2) were obtained with 1 mol% P₂O₅ and a sintering temperature of 820 °C.