金刚石的石墨化及其对炸药爆轰合成超微金刚石产出率的影响

 金刚石的石墨化对于炸药爆轰过程中金刚石的产出率有重要的影响。对碳相图进行了讨论,提出采用金刚石-石墨的动力学平衡线来评价炸药爆轰过程中金刚石的石墨化。通过数值模拟,对炸药爆轰过程中金刚石的石墨化进行了分析和讨论。     

论VLW状态方程

 论述了VLW状态方程中爆轰产物分子势参数的确定；根据不同类型炸药爆轰性能参数计算结果对炸药爆轰产物碳在CJ态的相进行了分析讨论，认为不同的炸药，产物碳有石墨和金刚石两种相存在；将VLW状态方程和BKW状态方程进行了比较分析，指出了BKW状态方程与VLW状态方程的区别及其产生的原因，并给出了VLW状态方程计算含能材料（包括高能炸药、燃料空气炸药、民用炸药）的爆轰性能参数计算结果。结果表明，计算值与实验值符合较好。     

基于统计物理的爆轰产物物态方程研究

用van der Waals等效单组分流体模型和Ross硬球微扰理论软球修正模型，计算爆轰气相产物的状态方程；用石墨相、金刚石相、类石墨液相和类金刚石液相４种相态描述凝聚成分，由Gibbs自由能最小确定不同状态下的凝聚产物相态.对爆轰产物混合系统采用Gibbs自由能最小原理，通过化学平衡方程组求解炸药爆轰产物系统的平衡组分，计算结果与Becker-Kistiakowsky-Wilson (BKW)和Lennard-Jones-Devonshire结果相近.使用该理论对炸药的爆轰参数做了预言，与BKW，Jo 关键词： 爆轰产物 物态方程 化学平衡方程组     

马赫反射效应在炸药爆轰合成金刚石中的应用

 在爆轰法合成超细金刚石中，利用马赫效应提高金刚石得率。用Whitham方法计算马赫杆上的爆轰参数。实验采用中间为TNT药柱、外边包裹TNT/RDX（30/70）的装药，在爆炸罐氮气介质中爆炸，超细金刚石得率为6%，包裹盐后得率超过10%。     

马赫反应效应在炸药爆轰合成金刚石中的应用

在爆轰法合成超细金刚石中，利用马赫效应提高金刚石得率。用Ｗｈｉｔｈａｍ方法计算了马赫杆上的爆轰参数。实验采用中间为ＴＮＴ的药柱、外边包裹ＴＮＴ／ＲＤＸ（３０／７０）的装药，在爆炸罐氮气介质中爆炸，超细金刚石得率为６％，包裹盐后得率超过１０％。     

PETN炸药爆轰产物状态方程的理论研究

 采用van der Waals等效单组分流体模型和Ross硬球微扰理论软球修正模型,计算爆轰气相产物的状态方程;用石墨相、金刚石相、类石墨液相和类金刚石液相4种相态描述凝聚成分,由Gibbs自由能最小原理确定不同状态下的凝聚产物相态。对爆轰产物混合系统采用自由能最小原理,通过化学平衡方程组求解炸药爆轰产物系统的平衡组分。使用该理论计算PETN炸药Chapman-Jouguet（CJ）点的爆轰参数,其值与实验值符合得很好;同时计算了以CJ点为起始点的等熵卸载线,并与传统的Jones-Wilkins-Lee（JWL）状态方程的计算结果进行比较,发现计算的γ值是单调递减的,而JWL状态方程计算的γ值却出现了“双峰”现象。分析认为,传统的JWL状态方程给出的“双峰”变化,是由其函数形式自身决定的,并不对应实际物理过程。     

气相/凝聚炸药爆轰合成的碳包铜纳米颗粒特征

采用凝聚炸药爆轰和气相爆轰分别制备碳包铜纳米颗粒,并利用XRD,Raman和TEM等方法对合成纳米产物进行对比分析。其中凝聚炸药爆轰法以柠檬酸铜干凝胶、油酸和黑索金为原料按照一定比例配成爆炸源,在氮气的保护氛围中引爆；而气相爆轰法以乙酰丙酮铜为原料,分别以H2和O2,H2和空气为爆炸源,在负氧条件下引爆。通过XRD,Raman和TEM分析结果表明,两类爆轰法均可得到分散性良好的碳包覆铜纳米颗粒,碳壳石墨化程度较高。气相爆轰可以合成10 nm以下的纳米晶粒,而凝聚炸药爆轰合成的晶粒尺寸在20~40 nm,且存在较多空壳结构；气相爆轰产物其碳壳尺寸在2~3 nm,凝聚炸药爆轰产物其碳壳尺寸在2~5 nm。     

多壁碳纳米管的爆轰改性

为研究爆轰反应对多壁碳纳米管(MWCNTs)形貌与物相的影响,将按一定质量配比制备的MWCNTs混合炸药在密闭的反应釜内引爆,并利用透射电镜和X射线衍射仪对爆轰前、后MWCNTs的形貌与物相分别进行了表征。结果发现:MWCNTs的质量分数在30%~40%时,混合炸药能够顺利起爆,并可收集到大量的样品;爆轰反应后,MWCNTs的形貌与物相发生了巨大变化,由管状结构变成以碳片、碳棒、碳球为主的结构,并有明显的团聚现象;有少量MWCNTs依附于碳片等结构边缘;样品以不定型碳为主,其石墨化程度远低于初始MWCNTs,并随着MWCNTs质量比的增大,样品的石墨化程度增大。     

冲击引起石墨→金刚石相转变机理的探讨

 通过对冲击引起石墨转变为金刚石两种相转变模型的比较和冲击波在疏松介质中传播特性的分析,研究了在冲击波阵面内形成热斑的机制和引起原子发生异常迁移的机制,进而探讨了在冲击波阵面内,在热斑区,石墨→金刚石的相变过程,以及卸载时金刚石的石墨化过程。     

初始温度及碳源对碳纳米管气相爆轰法合成的影响

改变初始温度以及分别使用甲烷和乙炔气体作碳源时气相爆轰合成碳纳米管,研究了初始温度与不同碳源对碳纳米管的影响。利用X射线衍射(XRD)、透射电镜(TEM)、拉曼(Raman)光谱等对碳纳米管进行表征。结果表明,随着初始温度的升高,所合成的碳纳米管的产量减少且石墨化程度降低,但管壁会变得光滑且管径有所增加。当使用乙炔时,所合成的产物中没有碳纳米管,而是合成了石墨化程度较高的无定形碳,随着催化剂量的增加,产物中碳包覆颗粒增多且包覆层清晰可见,但存在结构缺陷。当初始温度在110~130 ℃时,使用甲烷气体运用气相爆轰的手段是合成碳纳米管的较佳方案。     

Synthesis mechanism and technology of ultrafine diamond from detonation

Ultrafine diamond (UFD) is a hybrid product of explosion mechanics and material science. In this paper, we established the synthesis mechanism of UFD, built the direct-simulation Monte Carlo computing method for the generation of liquid drops from free carbon through coagulation during detonation, and constructed the computing programs for explosion thermodynamics conditions and phase-transition dynamics. The synthesis and purification technology were studied systemically.     

EGR率对生物柴油颗粒纳米结构的影响

为研究同时运用废气再循环(EGR)技术和燃用生物柴油对柴油机排气颗粒纳米结构的影响,分别采集0%,15%,30% EGR率下186F柴油机燃用生物柴油时的排气颗粒,并用激光拉曼光谱仪测得颗粒光谱,使用五带法对一阶拉曼光谱进行拟合,分析拟合曲线参数,计算颗粒微晶尺寸和碳碳键长度。结果表明：EGR率为30%时,生物柴油颗粒光谱的半高宽(FWHM)最大,代表化学异相性最强并且颗粒中的物质种类最多,随着EGR率降低,半高宽逐渐减小;当EGR率从0%升高到30%,I_D/I_G逐渐增大,代表石墨化程度降低,颗粒中的石墨结构减少;同时,I_D1/I_D2从0% EGR率的8左右降低到15%和30% EGR率的4左右,代表EGR率升高,颗粒内部缺陷由空位缺陷向石墨烯边缘缺陷发展;随着EGR率升高,微晶尺寸逐渐减小,碳碳键长度基本不变。     

C60分子石墨化的研究

测量了不同激光功率照射下，在具有不同导热率的三种衬底上蒸镀膜所吸附的Ｃ６０分子的振动光谱。发现在激光功率达到８００ｍＷ时，Ｃ６０分子发生“石墨子”。对石墨化的起因做了定性分析。     

Influence of the cumulative effects of multiple laser pulses on laser-induced incandescence signals from soot

The effect of multiple laser pulses reaching soot particles before an actual laser-induced incandescence (LII) measurement is investigated in order to gain some insights on soot morphological and fine structure changes due to rapid laser heating. Soot, extracted from a premixed and a quenched diffusion flames, is flowing through a tubular cell and undergoes a variable number of pulses at different fluence. The response of soot is studied by the two-color LII technique. Transmission electron microscopy (TEM) analysis of laser-modified soot aggregates from the diffusion flame is also presented. The results indicate that even at low laser fluences a permanent soot transformation is induced causing an increase in the absorption function E(m). This is interpreted as an induced graphitization of soot particles by the laser pulse heating. At high fluences the vaporization process and a profound restructuring of soot particles affect the morphology of the aggregates. Soot from diffusion and premixed flames behaves in a similar way although this similarity occurs at different fluence levels indicating a different initial fine structure of soot particles.     

On the mechanism of the detonation of organic high explosives

This article presents a further analysis of isotopic labeling data on the mechanism of the detonation of TNT-, RDX-, and HMX-containing mixtures and on the release of free carbon from these mixtures. The distribution of carbon isotopes among the condensed explosion products and, for the first time, among the gaseous ones is considered in relation to the particle size of the mixed explosives. A sequence of main chemical reactions in the detonation wave is suggested to account for the experimental data discussed.     

Macrokinetics of the retention of condensed carbon and detonation diamond in a hermetic explosion chamber

The effect of the thermophysical parameters of a cooling medium on the macrokinetics of secondary physicochemical processes that occur in a hermetic chamber after the explosion of a solid explosive charge is studied. The yields of condensed carbon and the content of the diamond phase in it are mainly determined by the temperature of the medium in the chamber after explosion. The maximum yield of detonation diamond synthesized from a trinitrotoluene-hexogen TG50/50 alloy is equal to ～10% of the initial explosive mass and is achieved when the steady-state temperature of the medium in the chamber does not exceed T_m=550±50 K. As this temperature increases, the yield of detonation diamond decreases approximately in inverse proportion to the temperature, and, at T_m>2800 K, there is virtually no diamond phase in the explosion products. The conversion of condensed carbon due to the presence of the oxygen-containing components of the explosion products (CO₂, H₂O) begins at a temperature of the medium of above 1550±150 K. The decrease in the final energy release that is experimentally detected in calorimetric studies in the case of an explosion of solid explosives with a negative oxygen balance in an inert gaseous medium or in the case where explosives are surrounded by massive shells results from the endothermic conversion of condensed carbon, which absorbs a significant portion of the explosion energy.