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一、前言爆轰波速度和爆轰波压力是爆轰学领域中常见的两个参数。爆轰波速度的测量从导特利斯法到电探针或光扫描方法建立以来,数十年中基本未出现反复,以此为依据的早期爆轰理论研究,曾取得较好的进展。爆轰波压力测量已有40年历史,自本世纪50年代起爆压测量方法公布以来,地尔用自由面速度测量爆压的数据已得到公认,但至目前各国实验室已公布的测量数据却极不相同,疑点很多。近年来与C-J理论和Z-N-D模型相矛盾的事实出现后,导 相似文献
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针对水平环状流液膜厚度沿周向分布的不对称性 ,用 5组双平行电导探针测量了水平管内气液环状流沿周向的瞬态液膜厚度 ,得到了平均液膜厚度沿周向的分布规律 .分析了液膜向上输送的机理 .为更为准确地预测液膜厚度 ,综合考虑了扰动波抽吸作用机理、气体二次流机理及液滴沉降和携带机理 ;通过量级比较和应力平衡的方法 ,提出了一个预测液膜厚度沿周向分布的理论模型 .数值模拟结果表明预测值与实验测量结果符合较好 相似文献
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一、前言爆轰波速度和爆轰波压力是爆轰学领域中常见的两个参数。爆轰波速度的测量从导特利斯法到电探针或光扫描方法建立以来,数十年中基本未出现反复,以此为依据的早期爆轰理论研究,曾取得较好的进展。爆轰波压力测量已有40年历史,自本世纪50年代起爆压测量方法公布以来,地尔用自由面速度测量爆压的数据已得到公认,但至目前各国实验室已公布的测量数据却极不相同,疑点很多。近年来与C—J理论和Z-N-D模型相矛盾的事实出现后,导致爆压测量的理论依据发生动摇,感到爆压测量中问题很多。当前爆轰波压力尚没有很好的测量方法,这是需要进一步解决的问题。在美国第四届爆轰会议上,戴维斯曾根据麦德和克雷格试验结果,提出了Z—N-D模型已不实用的观点。此后,国际上展开了讨论,国内爆轰学界不少同志也已就此问题进行研究和发表文章、本文拟就爆轰波C-J压力测量中存在的问题进行探讨。 相似文献
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《粘接》2021,48(10)
针对现有量子点影像探针存在荧光性质不可控、生物毒性强的问题,本研究结合现有的CuInS量子点探针,研究制备出一种掺杂Zn离子可简易合成的ZCIS/ZnS量子点纳米探针,并通过改进其水溶性,得到一种可直接应用于医学肿瘤影像的改进ZCIS/ZnS量子点纳米探针。为提高该量子点纳米探针的靶向性,研究根据EDC偶联的原理,通过将改进ZCIS/ZnS量子点纳米探针与cRGD多肽进行偶联,得到ZCIS/ZnS-cRGD量子点纳米探针,并从结构形态、细胞毒性和离体荧光3个方面重点评估了该量子点纳米探针,并通过实验论证了其有效性和实用性。实验结果证明,本研究制备的ZCIS/ZnS-cRGD量子点纳米探针是一种有效的肿瘤靶向探针,可用于实际肿瘤靶向检测。 相似文献
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从R3 克隆中提取并纯化流行性出血热R2 2 株M片段cDNA ,用光敏生物素标记而制备出生物素化的cDNA探针。用此探针与R2 2 株、76 118株及R3 克隆进行斑点杂交 ,均出现阳性杂交信号 ,而与仙台病毒、鼠肺炎病毒及BALB/c小鼠肝细胞、Vero E6细胞和SP2 / 0细胞杂交均为阴性。探针的灵敏度为 2 5pg目的核酸。用此探针测定了来自 9个单位 12株人用鼠源性杂交瘤细胞和 7个单抗制剂均为阴性。该结果与血清学检验结果一致 相似文献
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稳态荧光探针研究Guerbet醇聚氧乙烯醚羧酸钠的聚集行为 总被引:6,自引:3,他引:3
以芘为荧光探针、二苯甲酮为猝灭剂,用稳态荧光探针法测定了合成的4种具有支链结构的Guerbet醇聚氧乙烯醚羧酸钠的临界胶束浓度和胶团的聚集数.结果表明,用稳态荧光探针法得到的临界胶束浓度(CMC)数值与表面张力法相差不大.结合临界胶束浓度、胶束微环境的极性和胶束聚集数的变化规律,推测了这类表面活性剂形成的胶束聚集体的结构形态. 相似文献
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分析了压力波动信号互相关求液塞速度存在的不足,引入了差压波动分析法,明确了液塞到达和离开上、下游测压点的时刻与差压波动信号起峰点及落峰点位置的关系;分析了电导探针信号、差压信号和压力信号互相关所求得的相关速度的含义,指出差压互相关得到的是液塞运动速度,电导探针信号互相关得到的是液塞速度与液膜段界面波速度的平均值,压力信号互相关得到的相关速度具有随机性;明确了差压信号脉冲宽度为液塞从传感器上游测压点运动到下游测压点的时间间隔,脉冲宽度与液塞速度的乘积为液塞长度与差压传感器间距之和.最后,按照上述方法分类,把空气-水、柴油和机械油的试验数据的分析结果与文献中报道的液塞速度和长度数据进行了对比,结果吻合得很好. 相似文献
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The transport properties of ionic liquids (ILs) are crucial properties in view of their applications in electrochem-ical devices. One of the most important advantages of ILs is that their chemical–physical properties and conse-quently their bulk performances can be well tuned by optimizing the chemical structures of their ions. This will require elucidating the structural features of the ions that fundamentally determine the characteristics of the nanostructures and the viscosities of ILs. Here we showed for the first time that the“rigidity”, the order, and the compactness of the three-dimensional ionic networks generated by the anions and the cation head groups determine the formation and the sizes of the nanostructures in the apolar domains of ILs. We also found that the properties of ionic networks are governed by the conformational flexibility and the symmetry of the anion and/or the cation head group. The thermal stability of the nanostructures of ILs was shown to be con-trolled by the sensitivity of the conformational equilibrium of the anion to the change of temperature. We showed that the viscosity of ILs is strongly related to the symmetry and the flexibility of the constitute ions rather than to the size of the nanostructures of ILs. Therefore, the characteristics of the nanostructures and the viscosities of ILs, especially the thermal stability of the nanostructures, can be fine-tuned by tailoring the symmetry and the conformational flexibility of the anion. 相似文献
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Investigation of the effects of fatty acids on the compressive strength of the concrete and the grindability of the cement 总被引:1,自引:0,他引:1
In cement industry, a great energy consumption has been observed during grinding of clinker. To reduce this consumption, some waste products have been used as grinding aids.In this investigation, the effects of sunflower oil (SO), oleic acid (OA), stearic acid (SA), myristic acid (MA) and lauric acid (LA) on the fineness and strength of the cement have been examined. These aids were added into clinker in certain ratios based on the cement clinker weight and the grinding has been done for a definite time at the same condition.All of the fatty acids used increased the fineness as compared with the cement without the grinding additives. SO and OA decreased the strength significantly, LA decreased it to a lesser extent and SA increased it definitely according to the common cement. But MA did not alter the strength of the cement as much as SA. In addition, the covering of the balls influences the grinding of cement clinker unfavourably. 相似文献
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Polyurethaneureas (PUU), which were synthesized from 4,4′-diphenylmethane diisocyanate (MDI), poly(ethylene glycol) (PEG), and 3,5-diaminobanzoic acid (DABA), were used as polyelectrolytes in this study. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) were used to monitor the effect of the various kinds of PEG on the changes in morphology of PUU electrolytes corresponding to the concentration of lithium perchlorate (LiClO4) dopants. The results of DSC and FT-IR indicate the Li+ ions coordinate with the soft and hard segments. Additionally, the crystallinity of the PEG soft segment and the ordered hydrogen-bonded urea carbonyl groups decreased with increasing salt concentration. Impedance spectroscopy (IS) measurements show that the PUU electrolyte with the high phase separation degree has the high ionic conductivity. The hard-segment Tg and the soft-segment Tm influence the conductivity behavior of polyelectrolytes with increasing measurement temperature. 相似文献
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In spinning basalt fibres, the drafting force is in the same range as in spinning of glass fibres. The effect of the drafting
force can not be considered in the calculation for the strength and rigidity of the bottom of the spinneret.
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Translated from Khimicheskie Volokna, No. 5, pp. 47–50, September–October, 2007. 相似文献
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组合凹模的应力分析是一个非常复杂的问题,对其进行精确分析是解决模具寿命的关键。本文采用有限元分析软件Ansys对转子的组合凹模进行了分析,为转子组合凹模的优化设计提供了依据。 相似文献
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以气煤、肥煤、焦煤、瘦煤为样煤,进行了样煤的粉碎、有机溶剂溶胀和硝酸氧化处理,考察了处理后煤样中的药用腐植酸得率。结果表明,吡啶和N,N-二甲基吡咯烷酮是溶胀较好的溶剂;样煤粉碎后,随着粒度的减小,煤的溶胀率增加;粒度粉碎至200目的气、肥煤经吡啶溶胀和硝酸氧化后,煤样的药用腐植酸得率可达到73.0%和71.4%,而经甲醇溶胀和硝酸氧化的200目气煤药用腐植酸得率为56.4%和58.4%。实验结果表明,煤样经过溶胀和硝酸氧化处理,对药用腐植酸的提取有促进作用。 相似文献
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Igor G. Medvedev 《Electrochimica acta》2008,53(22):6545-6558
Effect of the density of the electronic states at the valence orbital of the bridge redox molecule on the dependence of the tunnel current on the overvoltage and on the width at half maximum of the current-overvoltage curve is studied. A number of the approximate expressions for the density of states, the tunnel current and the width are obtained in the fully adiabatic limit for different particular cases. It is shown that at small values of the coupling of the electronic levels of the electrodes with the valence orbital of the redox molecule and the small values of the bias voltage two regions of the reorganization Gibbs energy exist with different dependence of the width on the reorganization Gibbs energy. The results of calculations of the density of states, the tunnel current and the width are presented and used for the interpretation of the experimental data [N.G. Tao, Phys. Rev. Lett. 76 (1996) 4066, I. Visoly-Fisher, K. Daie, Y. Terazono, C. Herrero, F. Fungo, L. Otero, E. Durantini, J.J. Silber, L. Sereno, D. Gust, T.A. Moore, A.L. Moore, S.M. Lindsay, PNAS 103 (2006) 8686]. 相似文献