基于ICGA的雷达与雷达干扰一体化信号的优化设计

现代雷达与雷达干扰一体化系统中一体化信号的优化设计对整个系统性能发挥具有深远意义。结合伪随机信号特点,运用时空混沌系统构造伪随机二相序列,并在分析一体化信号设计原则的基础上建立了一体化二相序列的优化模型,将基于自适应排序选择策略的混沌遗传算法应用于求解序列优化模型,给出了具体的解算步骤,并进行了实例仿真。仿真结果表明改进的混沌遗传算法有效地解决了雷达与雷达干扰一体化信号优化设计问题,得到了性能良好的一体化信号。     

在线操作员培训仿真系统在大型炼化一体化项目中的应用

随着石化装置工艺技术日益复杂,对工艺操作人员的技能要求也越来越高。为尽可能地提高操作人员的技能水平,自20世纪90年代和21世纪初以来,OTS得到了越来越广泛的应用。在详细介绍仿真技术的发展历史、OTS的发展趋势、分析不同项目对OTS的需求及技术要求的基础上,从OTS的技术方案制订、设计和工程实施等几个方面描述了OTS项目实施的全过程及其所取得良好的实际应用效果。但在OTS的整个生命周期中,OTS的项目实施和开工初期的操作工培训应用仅仅只是一个开始,要想充分发挥OTS的作用,还必须在精心维护的基础上不断开发其在生产方案优化和先进控制等方面的功能。     

大型石化项目全厂自动化实施策略的选取

随着石化项目的大型化、一体化和智能化,对于大型石化项目的全厂自动化已普遍采用框架性协议项目实施策略。介绍并比较了几种不同的全厂自动化项目实施策略的合同特点、优缺点和实施内容,并在选取理由、工作范围、供货范围和实际项目实施的成功经验和不足的基础上重点推荐了MICC策略,希望能给后续的全厂自动化项目实施的技术和管理人员提供有益帮助。     

C/C复合材料抗氧化技术(Ⅱ)

讨论了C/C复合材料氧化的机制及其抗氧化途径的理论依据和具体方法;重点综述了涂层抗氧化的研究现状、制备方法、制备涂层的关键问题及典型的抗氧化涂层,指出该研究领域应加强的研究方向.     

铸渗复合涂层对铝铸件表面硬度的影响

在铸渗过程中,采用复合涂层增强铝合金铸件表面的硬度.试验表明,复合涂料中的Cr、Al2O3和WC粉均能有效提高铸件表面硬度,碳纤维粉是一种新型材料,它与石墨具有相似的润滑性,同时能显著增强铸件的表面硬度;浇注温度是重要的工艺参数,适当提高浇注温度,有利于铸渗层的形成和表面硬度的提高.     

Microstructure and Mechanical Properties of C/C-ZrC-SiC Composites Fabricated by Reactive Melt Infiltration with Zr,Si Mixed Powders

To meet the increasing demand for advanced materials capable of operation over 2000℃for future thermal protection systems application,C/C—ZrC—SiC composites were fabricated by reactive melt infiltration(RMI) with Zr,Si mixed powders as raw materials.The structural evolution and formation mechanism of the C/C—ZrC -SiC composites were discussed,and the mechanical property of the as-prepared material was investigated by compression test.The results showed that after the RMI process,a special structure with ZrC-SiC multi-coating as outer layer and ZrC-SiC-PyC ceramics as inner matrix was formed.ZrC and SiC rich areas were formed in the composites and on the coating surface due to the formation of Zr-Si intermetallic compounds in the RMI process.Mechanical tests showed that the average compression strength of the C/C-ZrC-SiC composites was 133.86 MPa,and the carbon fibers in the composites were not seriously damaged after the RMI process.     

日本草在南方红壤山边沟果园套种适应性研究

通过对南方红壤山边沟果园套种日本草适应性的研究,发现新开山边沟果园4月套种日本草扦插苗当年的6月分萌数可达6条,8月可达16条,第二年的7月能达11.4条;当年6月干草量可达5 308 kg/hm2,8月达8 523 kg/hm2,比套种百喜草分别低2.61%、13.78%,种植第二年7月达17 333 kg/hm2,比百喜草增加8.33%;当年6月草层厚度可达25 cm,比百喜草低19.35%,当年8月达49 cm,种植第二年7月达46 cm,分别比百喜草高6.52%、2.2%;当年6月覆盖率可达55%,比百喜草低15.38%,当年8月达100%,比百喜草高2.04%,种植第二年7月与百喜草一样达100%;套种日本草当年土壤流失率比裸地减少79.41%,同时能有效改善果园的生态环境.     

Preparation and characterization of SO42-/TiO2 and S2O82-/TiO2 catalysts

Nanosized solid superacids SO₄ ²⁻/TiO₂ and S₂O₈ ²⁻/TiO₂, as well as MCM-41-supported SO₄ ²⁻/ZrO₂, were prepared. Their structures, acidities, and catalytic activities were investigated and compared using XRD, N₂ adsorption-desorption, and in situ FTIR-pyridine adsorption, as well as an evaluation reaction with pseudoionone cyclization. The results showed that SO₄ ²⁻/TiO₂ and S₂O₈ ²⁻/TiO₂ possess not only nanosized particles with diameters < 7.0 nm, a BET surface greater than 140 cm²/g and relatively regular mesostructures with pores around 4.0 nm, but also a pure anatase phase and strong acidity. Different from the Lewis acid nature of SO₄ ²⁻/ZrO₂/MCM-41, SO₄ ²⁻/TiO₂ and S₂O₈ ²⁻/TiO₂ exhibit mainly Bronsted acidities. The strongest Bronsted acid sites were produced on SO₄ ²⁻/TiO₂ promoted with H₂SO₄, while Lewis acid sites on S₂O₈ ²⁻/TiO₂ even stronger than those on SO₄ ²⁻/ZrO₂/MCM-41 were generated when persulfate solution was used as sulfating agent. Because of their distinct acid natures, SO₄ ²⁻/TiO₂ and S₂O₈ ²⁻/TiO₂ exhibited catalytic activities for the cyclization of pseudoionone that were much higher than that of SO₄ ²⁻/ZrO₂/MCM-41. It can be concluded that the existence of more Br?nsted acid sites was favorable for proton participation in the cyclization reaction. Translated from Journal of Chemical Engineering of Chinese Universities, 2006, 20(2): 239–244 [译自: 高校化学工程学报]     

Mechanical properties of B4C–CrB2 binary eutectic composites prepared by arc-melting

B₄C–CrB₂ composites were prepared by arc-melting using B₄C and CrB₂ powders as raw materials. The eutectic composition of B₄C–CrB₂ system was 30B₄C–70CrB₂ (mol%) with a labyrinth-like irregularly layered eutectic microstructure, composed of B₄C phase about 1–2 μm in thickness dispersing in CrB₂ matrix, much smaller than raw powders. The interface of the eutectic composite was well bonded, and there were edge dislocations at the interface to alleviate the interface mismatch. The eutectic temperature of B₄C–CrB₂ composites was approximately 2200 K. At the eutectic composition, the B₄C–CrB₂ composites showed the maximum Vickers hardness (24.6 GPa) and fracture toughness (4.3 MPa m^1/2) at room temperature.     

新型干法水泥生产线中电石渣掺量与节能效果

随着合肥水泥研究设计院(以下简称"我院")高掺量电石渣新型干法水泥生产线的研制成功,其显著的经济效益和环境效益,促使该成果得到了迅速的推广.但推广中每个厂都要面对的问题就是:电石渣到底该掺多少综合效果才最佳.本文就电石渣掺量及节能效果进行分析,供设计和实际生产参考.