微米级铝颗粒热氧化特性

利用同步热分析技术,以10 K·min~(-1)的加热速率将3种微米铝粉从室温加热至1110℃,分析获得的热重-微商热重-差热分祈曲线,并通过Satava-Sestak积分法计算得到氧化反应的动力学参数及最可几机理函数;利用扫描电镜(SEM)、X射线衍射(XRD)对不同阶段的氧化产物进行观察分析。结果表明,粒径越小的铝粉,越容易被氧化,其氧化程度也越深。微米铝粉的氧化过程可分为三个阶段:阶段Ⅰ,温度低于550℃,反应非常缓慢,Al颗粒表面的无定形氧化铝层缓慢生长;阶段Ⅱ,550~670℃,氧化层由无定形氧化铝向γ-Al_2O_3转变,新形成的γ-Al_2O_3层不能在Al颗粒表面形成一个连续完整的外壳,裸露的Al与氧气接触,因此在阶段Ⅱ开始时,氧化速率迅速增大,当γ-Al_2O_3层完全覆盖Al核后,氧化速率迅速降低;阶段Ⅲ,670~1110℃,在内部熔融态Al受热体积膨胀及氧化铝由γ-Al_2O_3向α-Al_2O_3转变引起表面积收缩的共同作用下,颗粒表面氧化壳层产生裂缝或破碎,活性Al释放,氧化反应非常剧烈,最终生成稳定的α-Al_2O_3。粒径越小的Al粉,其氧化反应的表观活化能越低,反应越容易进行;3种样品的热氧化反应均符合边界控制模型函数R3:G(α)=G(α)=1-(1-α)~(1/3),温度适用范围550~1110℃。     

锆粉对高氯酸钾热分解反应的影响

为研究平均粒径1μm的锆粉(Zr)对高氯酸钾(KClO_4)各步热分解反应的影响,通过X射线光电子能谱(XPS)和热重分析(TG/DTG)研究了纯KClO_4和质量比为50∶50的Zr/KClO_4两种体系的热分解过程。XPS结果表明,锆粉的加入促进了KClO_4第一步热分解生成KClO_3的可逆反应平衡向右移动。利用线性拟合方法求解了两步热分解过程的动力学三因子,计算结果表明,加入小粒径锆粉后第一步热分解的活化能降低,指前因子增大,最可几机理函数由G(α)=[-ln(1-α)]~(3/4)变为G(α)=-ln(1-α),热爆炸临界温度由587.7℃降至516.9℃;第二步热分解活化能升高,指前因子不变,最可几机理函数均为G(α)=-ln(1-α)。因此,锆粉的加入促进了KClO_4的第一步热分解,增加了反应的活性位点,使反应更易进行,提高了反应速率,但同时锆粉表面被氧化为氧化锆,作为惰性物质掺杂于KClO_4和KClO_3之间,使得第二步热分解的表观活化能升高,但其不参与反应,不改变反应机理     

HNF的热分解动力学和热安全性

为了解硝仿肼(HNF)的热分解动力学和热安全性,用真空安定性试验(VST)、差示扫描量热法(DSC)和热重法(TG)研究了HNF的热分解特性。根据HNF在升温速率为5,10,15,20℃·min-1时的DSC曲线的峰温和TG曲线的分解深度(α),分别用Kissinger法和Ozawa法计算了HNF热分解反应的表观活化能(Ek和Ea)和指前因子(Ak)、提出了描述HNF放热分解过程的动力学方程。计算了HNF热分解反应的热力学参数(活化自由能ΔG’,活化焓ΔH’和活化熵ΔS’)和HNF的热安全性参数(自发火温度Tbpo和自加速分解温度TSADT)。结果表明,HNF的放气量为0.41 m L·g-1,不超过2 m L·g-1的标准,显示HNF有良好的热安定性。HNF吸热熔融后的放热分解反应过程可分两个阶段。Ek=257.10 k J·mol-1,Ak=1.74×1033s-1,ΔG’=103.37 k J·mol-1、ΔH’=253.82 k J·mol-1,ΔS’=380.78 J·K-1·mol-1,Tbpo=400.28 K和TSADT=395.10 K。放热分解反应的动力学方程可描述为:对α=0.20~0.65的第一阶段dα/dt=kf(α)=Ae-ERT f(α)=5.14×1021×(1-α)[-ln(1-α)]12 exp(-1.81×104/T)对α=0.65~0.80的第二阶段dα/dt=kf(α)=Ae-ERT f(α)=3.30×1014×(1-α)[-ln(1-α)]-1exp(-1.33×104/T)     

机械球磨法制备纳米晶Zr粉及其燃烧性能

通过机械球磨法对微米Zr粉进行晶粒细化,采用X射线粉末衍射法分析了球磨时间对Zr粉的物相、晶粒尺寸及晶格应变大小的影响;采用扫描电镜和激光粒度分析仪对Zr粉形貌、粒径分布进行了表征,并研究了Zr粉球磨时间对Zr/KClO_4烟火剂光辐射时间特性的影响。结果表明:随着球磨时间的延长,Zr粉的颗粒尺寸先减小后增大,而晶粒尺寸则持续减小,同时晶格应变逐渐增大:当球磨时间为8 h时,Zr粉的粒径分布最均匀、平均粒径最小(0.8μm),晶粒尺寸为81.7 nm;球磨时间增加到20 h后,Zr粉的颗粒尺寸略有增大,但晶粒尺寸减小到最小值(15.4 nm)。对原料Zr粉进行球磨处理后,Zr/KClO_4烟火剂的光辐射时间缩短,球磨时间为8 h时,相比使用原料Zr粉的烟火剂,样品的光辐射时间(17 ms)缩短了32%,表明烟火剂燃烧速率的显著增加,并且峰值辐射强度增大。     

聚四氟乙烯基铝活性材料的热化学反应特性

为获得聚四氟乙烯（PTFE）基铝（Al）活性材料的热化学反应性能,开展包含不同Al粒径的PTFE基Al活性材料在不同升温速率下的热化学反应实验。采用湿混工艺制备包含50 nm和10 μm两种Al粒径的PTFE基Al活性材料,并利用差示扫描量热法与热重分析法分析它们在10 ℃/min、 15 ℃/min、20 ℃/min、30 ℃/min升温速率下的热化学反应行为。结果表明：在10~ 30 ℃/min升 温速率中,包含纳米Al颗粒的PTFE基Al试样都发生了反应放热,而包含微米Al颗粒的PTFE基Al试样在小于900 ℃时并未与PTFE分解产物发生反应; Al颗粒的加入会对PTFE的热分解起到一定催化作用;对于Al粒径为50 nm的PTFE基Al活性材料,随着升温速率的增大,反应放热峰的峰值温度不断向高温区移动（由10 ℃/min的578.9 ℃移动到30 ℃/min时的608.5 ℃）,单 位放热量逐渐增多（由10 ℃/min升温速率下的331.6 J/g升高到30 ℃/min升温速率下的641.3 J/g）;研究结果对PTFE基Al活性材料的工程化应用具有参考意义。     

锆粉粒径对锆/高氯酸钾混合点火药热分解性能的影响

通过热重(TG)和差示扫描量热(DSC)实验研究了锆粉粒径对锆/高氯酸钾混合含能体系热分解性能的影响。DSC显示,纯高氯酸钾主要存在3个吸热峰,最后1个峰前有1个小肩峰。加入1μm锆粉后,高氯酸钾中间的吸热峰裂分为1个小吸热峰和1个放热峰,同时使最后1个吸热峰前的肩峰消失,峰形也变得更加尖锐。相比1μm锆粉,-200目(约74μm)锆粉只改变了高氯酸钾的最后1个峰形。运用Kissinger法和Ozawa法计算活化能,发现小粒径锆粉的加入使高氯酸钾的活化能降低了40k J·mol-1,而大粒径锆粉却使其活化能增加了超过1倍。显然,1μm锆粉具有更高的反应活性,其催化效果更明显。     

高能碳氢燃料的热氧化动力学研究

采用TG-DSC同步热分析仪在氩气气氛下研究了挂式四氢双环戊二烯(exo-THDCP)的热解性能。用不同升温速率的PDSC曲线进一步考察了氧气氛围下exo-THDCP的热氧化性能。结果表明,在高压氧气下exo-THDCP在温度高于380.53℃时将会发生氧化分解反应,反应过程可认为是单步反应。分别用Popescu法、FWO法和KAS法计算获得了exo-THDCP的热氧化分解动力学参数,确定反应机理函数为Avrami-Erofeev方程(n=3/4)。3种方法得到的活化能数值具有良好的一致性,活化能与指前因子之间存在动力学补偿效应。     

非平衡态Al/PTFE反应材料制备及其热性能

用机械合金化方法制备了Al-Ni-Ti-Zr非平衡态合金粉末。将制备的Al基非平衡态合金粉末与聚四氟乙烯(PTFE)微米粉混合压制制备了非平衡态Al-Ni-Ti-Zr/PTFE反应材料。采用X射线衍射仪(XRD)和扫描电镜(SEM)表征了球磨过程中粉末的相组成和形貌特征。利用高分辨透射电子显微镜(HRTEM)和选区电子衍射(SAED)分析了球磨后合金粉末的相结构。利用差示扫描量热法(DSC)分析了非平衡态Al/PTFE反应材料的热行为。结果表明:通过机械合金化方法可以制备出Al基非平衡态合金粉末。存在弥散在Al基非晶基体中的纳米级微晶岛状区域。在升温速率10 K·min~(-1)、空气气氛下,非平衡态Al/PTFE反应材料的反应峰值温度为495℃,放热峰积面积为1775 J·g~(-1)。连续升温条件下,非平衡态Al/PTFE反应材料的放热反应具有典型的动力学特征,通过Kissinger法计算的反应活化能E_c为309.1 kJ·mol~(-1)。     

Al/Zr/KClO4点火药的低湿热老化机制

为了研究铝粉/锆粉/高氯酸钾(Al/Zr/KClO₄)点火药的低湿热老化机制,将Al/Zr/KClO₄点火药在85,71,60℃和50℃下分别进行加速老化,利用热分析技术、X射线光电子能谱(XPS)、扫描电镜-X射线能谱(SEM-EDS)分析了低湿条件下Al/Zr/KClO₄点火药热分解性能和表面元素与形貌随着温度和时间的变化。结果表明,在加速老化时,随着老化时间的增加,KClO₄晶体表面部分分子降解生成KClO₃和KCl,Zr表面在热的作用下进一步氧化生成ZrO₂,Al未见明显变化,同时,各组分表面形貌未发生变化。Al/Zr/KClO₄点火药热分解活化能和热焓值随着老化时间的增加呈现下降趋势,与未老化的点火药相比,85℃老化160 d活化能降低了29.57 kJ·mol^-1,热焓值降低了160 J·g^-1。以反应速率、热焓值、各组分表面元素参量拟合获得了点火药老化机理函数,发现反应速率、Z...     

GI-920炸药的热分解动力学研究

根据PETN和GI-920炸药在升温速率分别为5,10,20 K·min-1的DSC-TG曲线,对PETN和GI-920炸药的热分解过程进行了研究,用Ozawa法和非线性等转化率积分法获得PETN和GI-920炸药热分解动力学参数和机理函数.结果表明,PETN与GI-920炸药的热分解机理属随机成核和随后生长.在不同升温速率的TG曲线上,GI-920炸药热失重开始温度大致相同.GI-920炸药DSC曲线呈现一个吸热熔化峰和一个放热分解峰,130 ℃以下有良好的热稳定性.GI-920炸药热分解的活化能、指前因子和机理函数分别为156.02 kJ·mol-1、1.934×1017 s-1、f(α)=4/3(1-α)[-ln(1-α)](1)/(4),热分解动力学方程为: dα/dt=2.579×1017×(1-α)[-ln(1-α)](1)/(4)exp(-(1.876×104)/(T)).     

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.     

Method for Measuring Velocity of Warhead Fragments Based on Photoelectric Detection

For measuring velocity and impacting position of single fragment of warhead, a non-contact measuring method is proposed, in which a six-light-screen array, a position indicator, a multi-channel chronograph and a computer are used.The principle of measurement is described. The key device of the system is a light screen array sensor which consists of six light screens allocated with certain geometrical parameters. When the fragment flies through the light screen array, the time of passing through each of the screens is recorded by the multi-channel chronograph. According to the time data and the geometrical parameters of the array, the velocity vector and the location of the fragment can be calculated immediately. The presented method can be used to locate the fragment and to measure the real velocity on its flying direction. It can also be used to measure the velocity of a fragment swarm after the system is engineered further.     

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.     

数码电子雷管中影响点火头性能因素分析

阐述了数码电子雷管中,点火药剂细结晶三硝基间苯二酚铅（LTNR）的制备工艺;从点火药剂的种类、加入黏合剂的质量分数、桥丝直径、点火头的电阻值、防潮漆的蘸涂等方面对点火头性能的影响因素进行了探讨;通过震动试验、并联起爆试验、延期精度检测与考核,试验结果表明：一次性合成的细结晶LTNR是制造数码电子雷管点火头较为理想的点火药剂,按技术要求生产的点火头性能指标能够满足行业标准要求。     

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.     

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.