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1.
本较系统地研究了镍钼合金的电镀条件对镀层的化学组成,表面结构和析氢催化活性的影响。镀层中的钼含量和催化活性随镀液中钼含量的增加而增加。在较低pH值下电镀得到的镍钼合金具有较佳的析氢电催化活性。在lmol/L NaOH溶液,40℃和100mA/cm^2电解条件下,析氢过电位约为122mV.用X光电子能谱和扫描电镜分别分析了镀层的表面元素价态和表面结构组织。  相似文献   

2.
电镀条件对镍钼合金镀层结构组织和催化活性的影响   总被引:2,自引:0,他引:2  
本文较系统地研究了镍钼合金的电镀条件对镀层的化学组成、表面结构和析氢催化活性的影响。镀层中的钼含量和催化活性随镀液中钼含量的增加而增加。在较低pH值下电镀得到的镍钼合金具有较佳的析氢电催化活性。在1mol/LNaOH溶液,40℃和100mA/cm2电解条件下,析氢过电位约为122mV。用X光电子能谱和扫描电镜分别分析了镀层的表面元素价态和表面结构组织。  相似文献   

3.
锌镍合金镀层的组成与相结构的关系   总被引:2,自引:3,他引:2  
用X射线衍射等方法,研究了从碱性镀液电沉积的锌镍合金镀层的化学组成与相结构,晶粒尺寸,显微硬度的关系。结果表明,随着合金镀层中镍含量的提高,合金镀层由η和r-相共存转变为只有r-相;镀层的织构相应地由六方结构的(100)择优面转变为立方结构的(330)择优面。η-和r-相的晶粒尺寸随镀层镍含量的提高而降低;只有r-相时,晶粒尺寸降低更为显著。镀层的显微硬度当镍含量为9.0wt.%时呈现一极小点。  相似文献   

4.
本文采用酸性化学镀镍-磷合金镀液,通过改变还原剂浓度,制备一系列不同磷含量Ni—P合金镀层,研究磷含量对镀层性能的影响。表明镀层耐蚀性、硬度等性能与磷含量有直接关系。  相似文献   

5.
化学镀镍硼合金镀层组织形态及其形成机制   总被引:1,自引:0,他引:1  
基于化学镀镍硼合金镀层的组织形态和成分、结构.探讨了镍硼合金镀层的沉积规律.分析表明,镀层在侧向和纵向上的相对沉积速度快慢是影响镀层组织形态的关键因素.柱状组织的形成原因是由于纵向沉积速度相对较快,该组织镀层含镍量相对较高,结构是非晶晶态混合结构;圆粒状组织是在侧向、纵向沉积速度较接近的条件下形成的,其成分中硼的含量相对较高,镀层结构趋于完全非晶态.  相似文献   

6.
研究了化学复合镀Ni-P-B4C合金镀液的组成、工艺和镀层性能,研究的结果表明,镀液中的B4C微粒含量在10-15g.l^-1时,能获得性能较好的镀层,且具有特别高的硬度。  相似文献   

7.
化学复合镀Ni——P—SiC合金的研究   总被引:1,自引:0,他引:1  
研究了化学复合镀Ni-P-SiC合金镀液组成、工艺和镀层性能。研究的结果表明,镀液中SiC微粒含量为10-15g.l^-1时,可得到性能较好、具有很高硬度的复合镀层。  相似文献   

8.
电镀法制取镍硼合金镀层的研究   总被引:5,自引:1,他引:4  
研究了用电镀法制取镍硼合金的可能性。其电镀液是借鉴某种化学镀液的成分,并加入适当的稳定剂配制而成。文中较详细地研究了镀液组成和电流密度等因素对镀层含硼量沉积速度和电流效率的影响,从中得出了较适宜的镀液组成和电镀条件。在此条件下,可得到外观较好,含硼量为3%左右的镍硼合金镀层,其沉积速度为11 ̄15μm/h,电流效率大于50%。  相似文献   

9.
研究了化学镀Ni-Cu-P合金的工艺,对镀液的稳定性和镀层的性能进行分析研究,获得含Ni83.31%、Cu4.08%、P8.59%均匀无针孔的的镀层;镀层的结合力、耐蚀性良好;经热处理后镀层的硬镀达到993.4HV。  相似文献   

10.
采用高速电镀实验装置强制电解液湍流运动,在高电流密度下,对简单硫酸盐体系中Zn-Ni合金电沉积规律进行了研究,证明Zn-Ni共沉积为异常共沉积,镀液中[NI]/[Ni+Zn]比及电流密度增加,镀层镍含量上升;镀液流速增加,镍含量下降。确定了高速电镀该合金工艺。  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.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
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   

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.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  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.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

19.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

20.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

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