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1.
建立了适用于链烷烃类系统的过热极限的动力学计算方法。采用发展的动态液滴技术,测定了正戊烷与正庚烷,正辛烷、正壬烷二元混合物的过热极限温度。实验结果表明,过热极限温度随外压的增加而升高,且过热极限温度与外压基本呈线性关系,与组分的摩尔分数也基本呈线性关系。  相似文献   

2.
The subsolidus phase relations were determined experimentally in the system MgO-ZnO-SiO2 at 1.0 GPa and 1 200℃, by use of the high-pressure apparatus "piston-cylinder". The results showed characteristics of the phases assemblage different from that in similar ternary systems. It is impossible to form complete Mg2SiO4-Zn2SiO4 olivine and Mg2Si2O6-Zn2Si2O6 pyroxene solid solution. This is controlled by the properties of Zn2+ with an outer layer of electron (Ar)3d10, different from others transition metal ions, like Fe2+ , Ni2+ , Co2+ .  相似文献   

3.
采用国产DS6×800T铰链式六面顶压机技术,对过渡金属TaB粉末进行了高温高压烧结,并采用金刚石菱形压痕法对TaB维氏硬度进行了测量.在加载负荷为29.4N时,烧结压力为4GPa,烧结温度分别为900和1100℃时,测试得到TaB陶瓷的硬度分别为7.7±0.4和10.5±0.7GPa.说明在同一压力条件下,温度越高致密性越好,通过阿基米德法,计算得到了TaB的相对密度为13.5g/cm3.  相似文献   

4.
Chen J  Weidner DJ  Vaughan MT 《Nature》2002,419(6909):824-826
The Earth's lower mantle consists mainly of (Mg,Fe)SiO3 perovskite and (Mg,Fe)O magnesiowüstite, with the perovskite taking up at least 70 per cent of the total volume. Although the rheology of olivine, the dominant upper-mantle mineral, has been extensively studied, knowledge about the rheological behaviour of perovskite is limited. Seismological studies indicate that slabs of subducting oceanic lithosphere are often deflected horizontally at the perovskite-forming depth, and changes in the Earth's shape and gravity field during glacial rebound indicate that viscosity increases in the lower part of the mantle. The rheological properties of the perovskite may be important in governing these phenomena. But (Mg,Fe)SiO3 perovskite is not stable at high temperatures under ambient pressure, and therefore mechanical tests on (Mg,Fe)SiO3 perovskite are difficult. Most rheological studies of perovskite have been performed on analogous materials, and the experimental data on (Mg,Fe)SiO3 perovskite are limited to strength measurements at room temperature in a diamond-anvil cell and microhardness tests at ambient conditions. Here we report results of strength and stress relaxation measurements of (Mg(0.9)Fe(0.1))SiO3 perovskite at high pressure and temperature. Compared with the transition-zone mineral ringwoodite at the same pressure and temperature, we found that perovskite is weaker at room temperature, which is consistent with a previous diamond-anvil-cell experiment, but that perovskite is stronger than ringwoodite at high temperature.  相似文献   

5.
6.
高温高压条件下甲烷和二氧化碳溶解度试验   总被引:1,自引:1,他引:1  
根据不同温度和压力条件下测得的甲烷和二氧化碳两种气体在碳酸氢钠型水中的溶解度数据,对两种气体的溶解度与温度、压力及地层水矿化度之间的关系进行研究。结果表明:在地层水中的溶解机制不同,导致两种气体的溶解度值随温度、压力条件的变化具有不同的演变特征;综合前人低温(小于90℃)测试的溶解度数据,可将甲烷溶解度与温度之间的演变关系划分为缓慢递减(0~80℃)、快速递增(80~150℃)和缓慢递增(大于150℃)3个阶段;二氧化碳溶解度随温度的升高而逐渐降低,随压力升高而逐渐增大,其溶解与析离能力受压力影响更为明显;实际地层中,两种气体间溶解度的差异演变影响了天然气的空间分布。  相似文献   

7.
CO2环境介质下16Mn钢的高温高压腐蚀性能   总被引:1,自引:0,他引:1  
利用高温高压釜,通过失重法、SEM、XRD以及电子探针微观结构分析等方法,对16Mn钢在3种不同高温条件下以及1 MPa分压的饱和CO2环境介质中的腐蚀性能进行研究.结果表明,在60、90、120℃下,16Mn钢发生严重的CO2腐蚀,表现出高的腐蚀速率,且伴有不同程度的点蚀、条状腐蚀特征.随着温度的升高,腐蚀速率呈下降再上升的趋势,90℃时最小,各温度下表面都生成了Fe3C为主的腐蚀产物膜。研究发现,Cl-为点蚀的"激发剂",并且在点蚀坑内富集,导致局部Cl-浓度差不同,形成电偶腐蚀,促进点蚀发生;腐蚀过程显示CO2腐蚀的局部腐蚀特征是各种因素相互作用的结果.  相似文献   

8.
Chandra P  Coleman P  Mydosh JA  Tripathi V 《Nature》2002,417(6891):831-834
When matter is cooled from high temperatures, collective instabilities develop among its constituent particles that lead to new kinds of order. An anomaly in the specific heat is a classic signature of this phenomenon. Usually the associated order is easily identified, but sometimes its nature remains elusive. The heavy fermion metal URu(2)Si(2) is one such example, where the order responsible for the sharp specific heat anomaly at T(0) = 17 K has remained unidentified despite more than seventeen years of effort. In URu(2)Si(2), the coexistence of large electron electron repulsion and antiferromagnetic fluctuations leads to an almost incompressible heavy electron fluid, where anisotropically paired quasiparticle states are energetically favoured. Here we develop a proposal for the nature of the hidden order in URu(2)Si(2). We show that incommensurate orbital antiferromagnetism, associated with circulating currents between the uranium ions, can account for the local fields and entropy loss observed at the 17 K transition. We make detailed predictions for the outcome of neutron scattering measurements based on this proposal, so that it can be tested experimentally.  相似文献   

9.
本文报道了2-氯-3-氨基-4-甲基吡啶的液相色谱分析方法。选用PROOIGY—ODS(3)为固定相,甲醇-水(70:30)为流动相。样品的变异系数为2.81%,平均回收率为97.61%,标准偏差小于0.29,线性相关系数为0.9942。  相似文献   

10.
通过对二硅炔(Si2H2)单线态进行G2(MP2)结构分析,发现了一个连接平衡构型Ⅳ和Ⅱ的新过渡态,计算表明,双桥构型Ⅶ是最稳定的单线态构型,但次稳构型Ⅳ异构为Ⅶ要跨过64.75kJ/mol的较高势垒,因此Ⅶ和Ⅳ是参与化学反应的两种基本构型。  相似文献   

11.
本文利用分子动力学方法和有效经验对势模型对MgO高温高压下的物态方程进行了研究,发现分子动力学方法得到的MgO岩盐结构的摩尔体积(温度范围:300-2000 K,压力范围:0~100 GPa)和实验结果吻合;另外,基于势模型的可靠性预测了300-2000K和0~100 GPa的温压范围内MgO岩盐结构的P-V-T关系,并对两种势模型计算结果进行了比较研究.计算得到的高温高压下MgO物态方程在地球物理学具有重要的参考价值.  相似文献   

12.
TiN在高压下结构稳定性的研究   总被引:1,自引:0,他引:1  
本实验利用金刚石压砧和同步辐射X衍射技术对TiN在高压下的行为进行了研究.通过实验获得的数据分析了TiN体积压缩曲线.结果表明:在0.45.4GPa的压力范围内,TiN样品的体积随着压强的增加曲线变化比较平滑,TiN没有发生相变.同时,通过三阶的Birch-Murnaghan状态方程,得出了TiN样品在相应的静水压下的体弹模量为B0=195=4.6GPa,一阶导数B’0固定为4.  相似文献   

13.
14.
高效液相色谱法在化妆品检测中的应用   总被引:1,自引:0,他引:1  
化妆品中对人体皮肤有害物质的含量会影响个人的皮肤健康,常用的检测手段——高效液相色谱法(HPLC)。对HPLC在化妆品检测中的应用进行了概述,对该方法的优缺点进行了总结,为以后在化妆品检测的应用提供参考。  相似文献   

15.
Multiple liquid crystal phases of DNA at high concentrations   总被引:3,自引:0,他引:3  
T E Strzelecka  M W Davidson  R L Rill 《Nature》1988,331(6155):457-460
DNA packaging in vivo is very tight, with volume concentrations approaching 70% w/v in sperm heads, virus capsids and bacterial nucleoids. The packaging mechanisms adopted may be related to the natural tendency of semi-rigid polymers to form liquid crystalline phases in concentrated solutions. We find that DNA forms at least three distinct liquid crystalline phases at concentrations comparable to those in vivo, with phase transitions occurring over relatively narrow ranges of DNA concentration. A weakly birefringent, dynamic, 'precholesteric' mesophase with microscopic textures intermediate between those of a nematic and a true cholesteric phase forms at the lowest concentrations required for phase separation. At slightly higher DNA concentrations, a second mesophase forms which is a strongly birefringent, well-ordered cholesteric phase with a concentration-dependent pitch varying from 2 to 10 micron. At the highest DNA concentrations, a phase forms which is two-dimensionally ordered and resembles smectic phases of thermotropic liquid crystals observed with small molecules.  相似文献   

16.
以工业应用成熟的PV型高效旋风分离器为基础,从改善分离器的强度入手,对PV型分离器顶部及进气口等部位的结构进行改造,提出了一种拱顶、直切入口、升气管偏心的新型旋风分离器.介绍了新型分离器与PV型的冷模对比性能试验、分离效率与压降计算及其在粉煤灰熔聚流化床气化、聚丙烯聚合反应装置中的应用.结果表明,新型分离器结构强度和分离性能优良,适合在高温、高压工况下应用.  相似文献   

17.
高温高压旋风分离器的性能及其应用   总被引:1,自引:0,他引:1  
以工业应用成熟的PV型高效旋风分离器为基础,从改善分离器的强度入手,对PV型分离器顶部及进气口等部位的结构进行改造,提出了一种拱顶、直切入口、升气管偏心的新型旋风分离器。介绍了新型分离器与PV型的冷模对比性能试验、分离效率与压降计算及其在粉煤灰熔聚流化床气化、聚丙烯聚合反应装置中的应用。结果表明,新型分离器结构强度和分离性能优良,适合在高温、高压工况下应用。  相似文献   

18.
根据混合物体积相加原理,由已知单质组分铁和钕(摩尔比分别为72.32%和26.68%)的Hugoniot数据计算出强磁材料钕铁硼在19 GPa~78 GPa压力范围内的状态方程.计算结果表明,理论计算结果与冲击压缩实验数据符合得很好.D-u关系的平均计算误差为±2.30%,P-V关系的平均计算误差为±9.12%.这表明本文基于Gruneisen模型导出的计算方法,在给定压力区间对钕铁硼这类金属间化合物是适用的;并且有理由预言该算法也适用于其它固体混合物及化合物的高压物态方程研究.  相似文献   

19.
The minimization of non-equilibrium plasma source at high pressure   总被引:2,自引:0,他引:2  
The density of plasma produced by atmospheric non-equilibrium plasma source is the function of energy dissipation rate in ionization electric field and gas particles momentum. The experiment shows that the plasma density highly rises with the increasing of energy dissipation rate and gas particles momentum. When the energy dissipation rate of activation field is 2.18 Wh/m^3 and the average gas particles momentum is 109×10^-22 g· m/s, the air throughput of plasma source whose volume is only 2.5 cm^3 can be up to 12 m^3/h and the density of plasma can be up to 10^10 cm^-3. The research can develop a method of producing minitype plasma source which is low energy consumption but high ion concentration used for chemical industry, environmental engineering and military.  相似文献   

20.
液-液相转移催化法合成5-邻氯苯基-2-呋喃甲酸芳酯   总被引:1,自引:0,他引:1  
在液-液相转移催化条件下,合成了15个5-邻氯苯基-2-呋喃甲酸芳酯,并通过红外光谱和元素分析确定了其结构  相似文献   

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