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1.
对用无压浸渗法制备高体积分数的SiC/Al复合材料的浸渗过程进行了分析。结果表明:温度在900~1100℃之间变化时,随着温度的升高浸渗深度增加;充分的浸渗时间可提高界面的润湿性,促使铝合金液顺利浸渗;Mg量为10%时浸渗能顺利进行;N2作为保护气氛,不但可以防止氧化,而且可以促进铝合金液对SiC颗粒的浸渗。  相似文献   

2.
高硅碱浸渣提铟   总被引:4,自引:2,他引:4  
碱浸渣是碱熔-浸出提绪后的铟渣,含铟量和含硅量较高,采用常规酸浸时会产生硅胶而难以过滤.分别用高温高酸浸出、硫酸化焙烧-浸出和预处理-浸出方法对高硅碱浸渣提铟进行研究.研究结果表明:这3种方法都能解决过滤难的问题,但采用预处理-浸出方法时铟的回收率最高.采用预处理-浸出提锢方法,即碱浸渣经过特殊处理后用硫酸浸出,在液固比为5 : 1,硫酸初始质量浓度为120~150 g/L,温度为80~90℃时搅拌浸出2.0 h,铟的浸出率高达95%.采用萃取-置换方法从浸出液中提取ω(In)>98%的粗锢,经电解精练制得了ω(In)>99.99%的精铟;从碱渣到粗铟,铟的直收率为90%.  相似文献   

3.
节节麦-小麦双倍体的合成、形态及细胞学稳定性   总被引:1,自引:1,他引:0  
对节节麦×小麦杂种胚愈伤组织再生植株的细胞学观察表明,胚再生植株染色体数目稳定(2n=28),杂种胚培养植株和胚再生植株花粉母细胞中期染色体构型平均分别为15.30Ⅰ+6.35Ⅱ和15.40Ⅰ+6.28Ⅱ. 杂种F1自交不孕,与小麦回交结实率0.88%,F1花粉可染率为2.30%. 利用改良浸根法对杂种F1加倍处理,加倍率为80%. 节节麦-小麦双倍体穗形偏向小麦,后代染色体数目2n=40~59,其花分母细胞减数分裂中期Ⅰ存在6~7个单价体、20~21二价体、1~2个多价体. 两个组合的双倍体平均结实率为73.33%、67.19%,单株最高结实率可达93.8%. 通过连续选择,可选育出结实率较高、稳定的节节麦-小麦双倍体或部分双倍体.  相似文献   

4.
以单官能度单体、双官能度单体、多官能度单体、引发剂、阻聚剂等原料制备了热固型有机浸渗密封剂,考察了上述组分对热固型有机浸渗密封剂的固化凝胶时间、固化后胶棒硬度等性能的影响。结果表明:热固型有机浸渗密封剂中m(单官能度单体)∶m(双官能度单体)∶m(多官能度单体)为13.8∶5.0∶2.8情况下,引发剂和阻聚剂占总质量的0.75%和0.1%时,具有最佳性能,在此组分比例下热固型有机浸渗密封剂聚合反应平均活化能Ea为(101.6±8)kJ/mol。  相似文献   

5.
介绍制麦塔工程中锥底浸麦层这一特种结构层施工特点,着重介绍其工艺流程组织,构件定位,模板支设,钢筋预应力筋安装,预埋件安装,预应力筋张拉,为此类工程施工提供借鉴。  相似文献   

6.
从柑桔皮中提取香精油的技术研究   总被引:12,自引:0,他引:12  
报导了从柑桔皮中提取香精油的水蒸汽蒸馏法和浸提法的研究结果,考察各种因素对出油率和香精油质量的影响.结果表明:不同品种的柑桔皮不宜混用;加入氯化钠可提高出油率和产品质量;若应浸提法,则用己烷作溶剂效果较好;香精油的主要成份为烯  相似文献   

7.
本文通过动物实验方法研究了麦胚油的预防高胆固醇血症及抗衰老营养价值。实验结果表明:1)以麦胚油做为饲料的脂肪来源可以满足实验动物的正常生理需要;2)麦胚油较等量的豆油或棕榈油有利于脂肪成分在动物体内的代谢;3)对实验性致高胆固醇血症动物模型,麦胚油对其具有较显著的预防作用;4)麦胚油能够有效延缓机体器官的老化,具有明显的抗衰老作用。实验结果提示,做为一种新型食物资源,麦胚油对于特殊生理状态,具有重要的营养价值及较大的开发价值。  相似文献   

8.
热浸镀铝、铝-锌-硅钢板的耐高温抗氧化性能   总被引:1,自引:0,他引:1  
采用熔剂法热浸镀铝、镀铝-锌-硅钢材在 1 000℃下进行了高温氧化实验。结果表明,两种热浸镀钢材的氧化增量随着浸镀温度的升高和时间的增加(即合金层厚度增厚)而减少。当合金层厚度达 120 μm 以上的镀铝钢材,其高温氧化增量几乎不随氧化时间的增加而增大。在浸镀温度、时间相同的条件下,浸镀铝比浸镀铝-锌-硅钢材的氧化增量显著少,即耐高温氧化性能好。  相似文献   

9.
为了解麦秸秆生物炭和稻壳灰作为土壤改良材料对黏性土耕作性能的影响,将两者分别按照体积比为10%、20%和30%加入上海黏性土中,采用室内试验的方法研究两种混合土的稠度指数和击实性能.试验结果表明:稻壳灰和麦秸秆生物炭均可以改善上海黏性土的稠度指数和击实性能,增加土壤的疏松度,提高持水能力;当施加量为20%时,改良效果最好;总体来说,麦秸秆生物炭的改良效果要优于稻壳灰.研究结果为资源回收利用提供理论依据和数据支撑,是对绿色农业健康经济发展的有益探索.  相似文献   

10.
以价廉易得的氟苯和戊二酸为原料,经傅-克反应、酰胺化、酮的还原、偶联和环合等数步反应合成依折麦布,总收率为7.5%.其中,用KRED238全细胞酮还原酶直接还原化合物5的羰基获得了具有S构型的羟基化合物中间体6,该步反应的收率为95%,(S)-羟基de值95.68%,还原反应的立体选择性高.该结果证实了生物催化技术应用于依折麦布合成中的可行性,为依折麦布绿色不对称合成工艺的发展提供了新的思路.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

14.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

15.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

16.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
19.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

20.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

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