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1.
拟带宽 Toeplitz 系统的秩 1 修正算法   总被引:2,自引:0,他引:2       下载免费PDF全文
本文以带宽Toeplitz系统的快速并行解法为基础,通过建立秩1的修正格式讨论了拟带宽Toeplitz系统的一种快速并行算法,其串行运算量为9nh+O(h).设p为处理机台数,当p≤n时,并行运算量为 ;当p=3n时,运算量为2h ̄2log2n+O(1),其中h表示拟带宽宽度。  相似文献   

2.
本文研究了溶胶-凝胶(Sol-gel)法制备碳纤维三维编织物增强氧化铝(Al2O3)基复合材料的成型工艺及其力学性能,研究了两种主要起始物Al(NO3)3、AlCl3配制的氧化铝溶胶对复合材料成型工艺和力学性能的影响。分别以Al(NO3)3和AlCl3为起始物,制备得到Ⅰ#、I#复合材料。研究表明,以Al(NO3)3为起始物配制的溶胶粘度较小,利于材料的致密化。经过溶胶浸渍、凝胶、裂解13个周期后,Ⅰ#材料的密度和室温三点弯曲强度分别为1.86g/cm3和145.2MPa,而II#材料的密度和室温三点弯曲强度分别为1.63g/cm3和104.1MPa,材料均呈典型的韧性断裂模式。用扫描电子显微镜(SEM)观察试样的断口形貌,发现断口表面有大量的纤维拔出,纤维表现了较好的增韧效果。  相似文献   

3.
讨论了平面系统x=-6+δx+ψ(x)「a+bh(x)」,y=x^2n0-1(n∈N)的极限环存在性,唯一性与不存在性。  相似文献   

4.
本文对二甲苯溶剂中MeSiHCl2 和甲醇的反应产物Me (OMe)2SiH 及MeSi(OMe)3 作了红外和核磁共振分析, 结果表明: 以红外谱图中Si-H 和苯环吸收带作为含量分析谱带, 采用比例法, 借助工作曲线,可确定反应产物的含量。亦可以通过对各组分处于不同化学位移下质子的核磁共振分析,采用归一化法,经过换算测定反应产物混合液中各组份含量。两种测定方法均简便快捷, 并对两法的测定结果作了分析比较。  相似文献   

5.
本文用对甲氧基苯酚、正溴丁烷、聚甲醛为原料, 经醚化, 双氯甲基化和碱性消除反应, 合成出长链共轭且可溶的聚(2甲氧基5丁氧基)亚苯基亚乙烯,用 I R 和1 H N M R 表征了中间体和聚合物的结构,并测定了聚合物的伏—安特性曲线。  相似文献   

6.
用固态反应法按分子式YBa2Cu2.7Ag0.3O7-δ(简称YBCAO)制备了样品,利用X射线衍射,R-T曲线及扫描电镜SEM研究了Ag对于YBCO超导性能的影响。实验结果表明:晶粒得以细化,YBCO超导性能的稳定性有所增强。本文对结果进行了讨论。  相似文献   

7.
合成了新发光试剂N-异鲁米诺,并对其化学发光性能进行了研究。在NaHCO-3NaOH 冲溶液中,H2O2浓度为0.1mol/L,CMIL浓度为0.088-2.5mmol/L,邻氯苯亚基丙二腈的发光强度不受CMIL浓度的影响。  相似文献   

8.
建立了用DS2,50%DS2水溶液(V/V),Na2CO3水溶液对VX消毒后的样品处理与制备的方法,比较了“氯化氢/甲醇除胺法”和“水中止除胺法”2种中止反应的特点。用气相色谱-质谱法进行了消毒后产物的分析与鉴定。并探讨了3种消毒剂与VX反应机理。  相似文献   

9.
通过Zn与Cu(NO_3)_2溶液反应的实验分析,提出了研究和全面认识置换反应的思路。对中学化学教师继续教育中实验教学应解决的问题进行了讨论。  相似文献   

10.
如果图G是n个顶点的直径为2的最小图,Zoltan Furedi证明了当n>n0时,E(G)≤[n^2/4].本文研究的是他由此提出的一个猜测,证明了在k=2,3,条件加强的情况下,猜测成立,并讨论了上述猜测不成立的情形。  相似文献   

11.
用1,4-二氯甲基-2,5-二甲基苯和1,4-二氯甲基-2-甲氧基-5-辛氧基苯共聚合成了一种可溶的聚对苯乙炔的衍生物,对共聚物结构进行了红外光谱、核磁共振氢谱表征  相似文献   

12.
设u、v是两个固定顶点,用b条内部互不相交且长度均为a的道路连接u、v所得到的图用Pa,b表示.Kathiresan证实P2r,2m-1(r,m均为任意正整数)是优美的,且猜想除了(a,b)=(2r+1,4s+2)外,所有的Pa,b都是优美的.杨元生已证实P2r+1,2m-1是优美的.本文证明P3,4m是优美图,从而当a=3时Kathiresan猜想成立.  相似文献   

13.
系统地研究了双钙钛矿结构氧化物Sr2FeMo1-xNbxO6中Mo位的Nb替代效应,发现Nb替代Mo可强烈抑制Sr2FeMoO6的金属导电性,并大大提高掺杂样品的电阻值和庞磁电阻特性,在5K下,Sr2FeMo0.6Nb0.4O6的庞磁电阻分别达到23%(1T)和31%(3T),在室温下,Sr2FeMo0.75Nb0.25O6的磁电阻分别达到4%(1T)和6%(3T).  相似文献   

14.
Heterocyclic skeleton (Azoles) and different energetic groups containing high performing explosives are highly emerged in recent years to meet the challenging requirements of energetic materials in both military and civilian applications with improved performance. For this purpose tetrazole (Azole) is identified as an attractive heterocyclic backbone with energetic functional groups nitro (-NO2), nitrato (-ONO2), nitrimino (-NNO2), and nitramino (–NH–NO2) to replace the traditionally used high performing explosives. The tetrazole based compounds having these energetic functional groups demonstrated advanced energetic performance (detonation velocity and pressure), densities, and heat of formation (HOF) and became a potential replacement of traditional energetic compounds such as RDX. This review presents a summary of the recently reported nitro-tetrazole energetic compounds containing poly-nitro, di/mono-nitro, nitrato/nitramino/nitrimino, bridged/bis/di tetrazole and nitro functional groups, describing their preparation methods, advance energetic properties, and further applications as high-performing explosives, especially those reported in the last decade. This review aims to provide a fresh concept for designing nitro-tetrazole based high performing explosives together with major challenges and perspectives.  相似文献   

15.
在合成中间体二(4-叔丁基苯基)羟乙酮基础上,进一步合成了双(1,2-二(4-叔丁基苯基)-1,2-二硫代双烯)镍络合物(DYE-02),利用核磁共振氢谱、红外光谱和元素分析等方法对中间体及DYE-02的结构进行了表征,并研究了DYE-02自身的光稳定性能及其对菁染料(Cy7)的光稳定作用.结果表明,与双(1,2-二苯基-1,2-二硫代双烯)镍络合物(DYE-01)相比,苯环上引入叔丁基后,DYE-02的最大近红外吸收波长在885nm,发生明显的红移,具备更好的自身光稳定性,并且能明显提高菁染料的光稳定性.  相似文献   

16.
To explore the effect of different positions and number of pyrrolidine bound to the carbon cage on the stabilization effect of fulleropyrrolidine derivatives to nitrocellulose (NC)/nitroglycerine (NG), we synthesized N-(4-methoxy) phenylpyrrolidine-C60 and four different of bis(N-(4-methoxy) phenylpyrrolidine)-C60 compounds through Prato reaction. Their structures were characterized by UV–vis, 1H NMR, 13C NMR, high-resolution mass spectroscopy, and single-crystal X-ray diffraction. Their stabilization effect to NC/NG were investigated using differential scanning calorimetry, methyl violet, vacuum stabilization effect, weight loss, and accelerating rate calorimeter tests. The results indicated these compounds had excellent stabilization effect to NC/NG. The stabilization effect of the fulleropyrrolidine bisadducts to NC/NG is significantly better than that of fulleropyrrolidine monoadduct and C60. Moreover, the position where pyrrolidine binds to fullerene in fulleropyrrolidine bisadducts is different, and its stabilization effect to NC is also different. The stabilization effect order of different bisadduct isomers to nitrocellulose is as follows: e-edge > trans-2> cis-2> trans-3. Electron paramagnetic resonance (EPR) and FT-IR were used to study the stabilization mechanism of fulleropyrrolidine derivatives to NC/NG. The EPR results also show that fulleropyrrolidine bisadducts with different addition sites have different abilities to absorb nitroxide, and their ability is better than that of the monoadduct and C60, which is consistent with the results of stabilization effect performance test.  相似文献   

17.
《防务技术》2020,16(3):705-711
In this study, based on two attractive energetic compounds pentazole (PZ) and tetraazacubane (TAC), a new family of high energy and high nitrogen compounds pentazolyltetraazacubanes were designed. Then, a different number of NH2 or NO2 groups were introduced into the system to further adjust the property. The structures, properties, and the structure-property relationship of designed molecules were investigated theoretically. The results showed that all nine designed compounds have extremely high heat of formation (HOF, 1226-2734 kJ/mol), good density (1.73–1.88 g/cm3), high detonation velocity (8.30–9.35 km/s), high detonation pressure (29.8–39.7 GPa) and acceptable sensitivity (ΔV: 41-87 Å3). These properties could be effectively positive adjusted by replacing one or two PZ rings by NH2 or/and NO2 groups, especially for the energy and sensitivity performance, which were increased and decreased obviously, respectively. As a result, two designed pentazolyltetraazacubanes were predicted to have higher energy and lower sensitivity than the famous high energy compound in use 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane, while two others have better combination property than 1,3,5-Trinitro-1,3,5-triazacyclohexane. In all, four new pentazolyltetraazacubanes with good combination performance were successfully designed by combining PZ with TAC, and the further property adjustment strategy of introducing a suitable amount of NH2/NO2 groups into the system. This work may help develop new cage energetic compounds.  相似文献   

18.
用四球机试验评价了所合成的有机钼化合物极压抗磨性能 .讨论了钼的化合价与有机钼化合物的极压抗磨性能的关系 .发现对黄原酸硫氧钼和硫代磷酸硫氧钼两类有机钼化合物均是含六价钼化合物的载荷性能最好 ;六价钼比五价钼化合物的反应活性高 ,可在更低的浓度下表现出最佳的抗磨效果 ;钼的化合价不影响硫代磷酸硫氧钼在基础油中的理化性能 .  相似文献   

19.
本文把长为N=N_1N_2(N_1为奇数)的离散Hartley变换(DHT)分解成N_1个长N_2的DHT及一些附加运算,附加运算也可以变成N_2个长N_1的DHT。由此得到计算它的一种MIMD并行算法,若用N_1台处理机并行计算,只需(?)个乘法步和(?)个加法步,这里M(N_2)和A(N_2)分别表示计算一个长N_2的DHT所需的乘法数及加法数。并行机的有效利用率接近于1。  相似文献   

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