基于ANN的喷射沉积ZA35合金热挤压工艺优化研究

采用人工神经网络的方法,研究了挤压比、挤压比压和挤压温度对喷射沉积ZA35合金力学特性的影响,建立了喷射沉积ZA35合金热挤压工艺的人工神经网络模型。模型的输入参数为挤压比、挤压比压和挤压温度,输出参数为合金的抗拉强度和伸长率,该模型可以预测ZA35合金在不同热挤压工艺参数下的力学特性,也可以优化热挤压工艺参数。模型结果与实验结果吻合良好,推荐喷射沉积ZA35合金热挤压工艺参数:挤压比压为430 MPa,挤压比为12,挤压温度为260℃。     

热挤压对喷射沉积TiCp/ZA35复合材料力学性能的影响

采用热挤压对喷射沉积TiCp/ZA35复合材料进行致密化处理,分析挤压比压、挤压温度、挤压比及挤压速率对复合材料力学性能的影响。结果表明:热挤压后,TiCp/ZA35复合材料中反应生成的增强相TiC颗粒在晶界和晶内分布均较均匀,组织中析出MnAl6强化相,相对密度提高;当挤压比压为430 MPa,温度为285℃,挤压比为12,速率为8 mm/s时,挤压后复合材料的抗拉强度为485.0 MPa、伸长率为9.53%。     

挤压比压对喷射沉积ZA35-3.5Mn合金组织及力学性能的影响

利用喷射沉积工艺制备ZA35-3.5Mn合金,研究挤压比压对其微观组织及力学性能的影响。结果表明:挤压比压由400 MPa升至460 MPa,锭坯合金晶粒逐渐细小,挤压比压再升高,合金组织变粗大,挤压后合金中析出富锰相。随着挤压比压的增加,抗拉强度、硬度及伸长率增加,当挤压比压为460 MPa,综合力学性能达到最大,挤压比压继续增加,抗拉强度和硬度略上升,而伸长率明显下降。     

喷射沉积Mg-9Al-4.5Ca合金的显微组织和力学性能研究

通过金相显微镜、X射线衍射仪、扫描电镜、拉伸试验机对喷射沉积工艺制备的Mg-9Al-4.5Ca锭坯沉积态和挤压态的显微组织、相组成与力学性能进行研究。结果表明:喷射沉积Mg-9Al-4.5Ca合金的组织较常规铸态细小,经热挤压加工后组织进一步细化,沉积态合金的组织为等轴晶,晶粒度为3～5μm;沉积坯的相组成为α-Mg、Al2Ca、Mg2Ca、Ca2Mg6Zn3和MgZn2,经热挤压后相组成转变为α-Mg、Al2Ca、Mg2Ca、Mg17Al12和MgZn2;合金挤压态的力学性能较常规变形镁合金MB7有显著提高,抗拉强度、屈服强度、延伸率分别为470MPa、390MPa、8%。合金的强化机制主要为细晶强化,固溶强化和弥散强化。     

Ni及热处理对ZA35合金阻尼性能的影响

研究合金元素Ni和热处理对ZA35合金组织和阻尼性能的影响。结果表明:0.3%Ni使ZA35合金组织细化,二次枝晶臂间距减小,热处理后出现粒状组织;ZA35合金的内耗随温度升高而增加,随测试频率升高而下降,在测试频率为1 Hz、温度为140℃,ZA35合金的内耗达到0.076;测试温度为140℃,ZA35-0.3%Ni合金阻尼较ZA35合金增加12.1%,热处理后阻尼较ZA35合金增加25.8%。     

高耐腐蚀Mg合金制造技术

日本专利JP2006 16664中公布了一种具有高耐腐蚀性能的Mg合金制造工艺。这种M合金材料是以Mg合金切削屑为原料,经过压制和热挤压（在常压下进行,挤压温度573—723K,挤压比25—400）处理后制成的。     

喷射沉积Mg-Al-Ca-Zn镁合金力学性能研究

采用喷射沉积加热挤压成形方法制备Mg-Al-Ca-Zn镁合金,使用SEM、TEM等技术对其组织和力学性能进行研究。结果表明:喷射沉积挤压态镁合金组织均匀、晶粒细小,合金中存在大量细小的第二相;沉积挤压态合金抗拉强度可达到425 MPa,延伸率为3%,细晶强化是其主要强化机制;时效处理对喷射沉积挤压态合金抗拉强度无明显影响,但会降低高合金化合金的延伸率,固溶时效处理会降低合金抗拉强度,但可提高低合金化合金的延伸率。     

时效时间对ZA35-1.35Si-0.3Zr合金组织及电化学性能的影响

用金相显微镜、XRD、扫描电镜以及电化学工作站,研究不同时效时间对ZA35-1.35Si-0.3Zr合金组织和电化学性能的影响。结果表明:固溶时效处理可以有效减小ZA35-1.35Si-0.3Zr合金晶粒尺寸,提高其电化学性能;时效时间为6 h时,合金晶粒尺寸最小,第二相数量明显增多且颗粒细小、分布均匀;在6 h时效时间下合金的电化学性能最好,腐蚀电流密度比铸态ZA35-1.35Si-0.3Zr合金降低71.9%;时效处理ZA35-1.35Si-0.3Zr合金在质量分数为3.5%的NaCl溶液中电化学性能增强的主要原因是合金的容抗弧变大,极化电阻增加,腐蚀速率降低。     

钨合金穿甲弹芯变形缺陷的产生形式和形成力学分析

在分析高比重钨合金弹芯挤压变形缺陷产生形式的基础上,利用钨合金变形体塑性区内的速度场分布,推导了变形钨合金弹芯形成内部破裂和表面破裂条件的力学判据,并绘制了两种变形缺陷的力学判据曲线图.试验结果表明,该力学判据将为合理制定液力挤压变形工艺参数、设计优化工模具结构、预测挤压变形缺陷和提高挤压制品质量提供重要的理论依据.     

双向挤压与螺旋复合变形有限元分析

以AZ31镁合金为研究对象,对双向挤压与螺旋复合变形模型进行工艺参数的数值模拟运算,分析工艺条件对AZ31镁合金在成型过程中等效应变和挤压力的影响。结果表明:双向挤压与螺旋复合变形可显著提高坯料变形过程的等效应变,随着挤压比的增加、挤压温度和挤压速度的升高,坯料所获得的等效应变值显著升高,双向挤压与螺旋复合变形AZ31镁合金的等效应变值可高达3.2。工艺条件的有限元分析为镁合金在双向挤压与螺旋复合变形的实际生产应用提供了重要参考价值。     

Nitrosation and Nitration of Tetraacetyldibenzylhexaazaisowurtzitane

Tetraacetyldibenzylhitane (TADBIW) was subjected to debenzylation by nitrosating with inorganic materials available commercially to synthesize tetraacetyldinitrosohexaazaisowurtzitane (TADNSIW). TADNSIW was purified, and its structure was determined by FTIR, 1H NMR, MS and element analysis. The debenzylation reaction of TADBIW gave quantitative benzaldehyde as a by-product. This indicates that the reaction produces an imine cation as an intermediate. Hexanitrohexaazaisowurtzitane (HNIW) was prepared from unpurified TADNSIW with the yield over 96.0 % and the purity more than 98.0 %. And the mechanism of the reaction from TADNSIW to HNIW is proposed to be oxidation of nitroso and nitration of acetyl on the molecule of TADNSIW, This reaction system involved is simple, and the reaction can complete within a short time and under mild conditions. The product can be easily to separate and the waste disposed readily.     

A Robust Algorithm for Watermarking 2D Vector Maps with Low Shape-Distortions

The technique of watermarking has been introduced into 2D vector maps for many potential applications such as protecting the copyright of important GIS （geographical information system） data and tracing the data source of military maps. In most previous works, although the validity of the map data could be preserved during the embedding procedure, the shape-distortions of the map elements are usually neglected which would tend to degrade the invisibility of the watermarking schemes. A shape-preserving algorithm for watermarking 2D vector maps is presented in this paper. A 1D distance sequence extracted from the original map is adopted as the cover data instead of 2D coordinates. A watermark bit is represented by changing the distributions of the cover data. The embedding procedure induces lower shape-distortions than in former works. Experimental results indicate better invisibility of the proposed scheme, as well as its robustness to certain attacks such as map simplification, interpolation, additive noise and most geometric transforms.     

Open Rule-setting System Applied to Conceptual Design of Engines

Open rule-setting method advanced in this paper concentrates on providing designers of engines with a convenient way to express their design innovations and develop the expected prototypes in the early CAD stage, and constitute effective models for the following analysis process of CAE and CAPP. The problems arisen in the process of conceptual design with the traditional experience-based development method are analyzed. Based on those analyses, open rule-setting method is presented and some associated technical problems are discussed. The functional framework of open rule-setting system was built as software engineering methods. The speciality of the engine product as a kind of complex product and the requirement of the engine product based on its structural particularity to rule-setting system are considered carefully. A demonstration is supplied to illustrate how the open rule-setting method enhances the efficiency and quality of the engine conceptual design.     

Research on Linux Network Device Driver

By analyzing the working principle of Linux network device driver, discussing the Linux network driver structure and its key technologies, the general network driver structure and its design methodologies in Linux system are summarized. Through modifying the network device driver of Linux device driver 3rd version snull, c and improving the COW technology, the Zero-Copy technology in Linux （kernel version 2.6.11 ） is implemented. In the end, the success test tells us that the thorough analysis of network device driver is the foundation of many applications, and it also provides a certain improvement to a lot of real applications, even to military application development.     

Improvement and Experiment of the Reamer in Vibra Cutter Against Wave Edge of Titanium Sheet Alloy Parts

By analyzing the influencing factors of part quality making of sheet alloy of titanium by vibra cutter, the shape of upper reamer is set as cylinder and wedge-shaped form, and the lower reamer as plain and hemicycle form, and its main structural parameters are defined as well. Then it is validated further that such improved vibra cutter reamer can be used to process curve-edged parts of titanium alloy sheet. The experimental result shows that the titanium alloy sheet parts processed by above equipment have no sharpen angles for convex parts and evident crevasse of concave-edged part. In summary, such improvement can eliminate the free-waved edge and improve the manufacture quality of titanium alloy sheet parts greatly.     

Experimental Study on the Small Flyer Initiating Behavior of Fine-grained Explosives

The initiating behavior of fine-grained explosives by small flyer is studied. The diameter of small flyer in this device is 1 ram. The test results indicate that the granularity of explosives has great effect on its flyer initiating sensitivity.The flyer initiating sensitivity of the fine-grained explosives is higher and the critical initiating energy is lower than that of common explosives. For common explosive, the flyer initiating sensitivity increases as the density is reduced. But for the fine-grained explosive, the test results are exactly opposite.     

Algorithm for Multi-laser-target Tracking Based on Clustering Fusion

Multi-laser-target tracking is an important subject in the field of signal processing of laser warners. A clustering method is applied to the measurement of laser warner, and the space-time fusion for measurements in the same cluster is accomplished. Real-time tracking of multi-laser-target and real-time picking of multi-laser-signal are introduced using data fusion of the measurements. A prototype device of the algorithm is built up. The results of experiments show that the algorithm is very effective.     

Robust Graded Sliding Mode Tracking Control for Low Speed Spinning Ballistic Missiles

The nonlinear dynamic model of spinning ballistic missiles is established during the first boosting phase of the missile. Based on the conventional backstepping sliding mode control and the assumption of a two time-scale separation of missile dynamics, a graded sliding mode controller is designed with two sub-sliding surfaces which have invariability to external disturbances and parameter perturbations, and a matrix which comprises three first order low pass filters is introduced to prevent ＂explosion of terms＂. Owing to the upper bounds of the uncertainties are difficult to obtain in advance, adaptive laws are introduced to estimate the values of the uncertainties in real-time. Eventually, the numerical simulation results given to show the proposed controller can ensure the steady flight of missiles.     

A Study on the Estimation of Aeroheating upon the Warhead Nose at Supersonic Speed

An expression for estimating the aeroheating on a warhead nose at different supersonic speeds is proposed by incorporating CFD （computational fluid dynamics） and the least-square method. Compared with the traditional estimation formula, the expression is more accurate, convenient and can be used in the optimized design of warheads. The error from the result obtained in the test of a ball cartridge flight is less than 3 %. It satisfies the engineering requirements.     

Influence of Installing Error on the Surface Shape Precision of the Axial Symmetry Aspheric Workpiece in Lapping

A method to calculate the surface shape error, which is caused by the installing error between the workpiece and the lapping tool in the process of form lapping, is proposed. The mathematical model which the installing translation error influences on the workpiece surface shape error is established. The changing rule of the error is simulated through the calculating example of the paraboloid workpiece. The results indicate that the surface shape error of the workpiece is increasing with the increase of the installing translation error, it is also increasing gradually along the center point of the curve surface to the edge, and the influence is severer to the curve surface with great curvature than that of the small curvature when the translation error is the same.