共查询到20条相似文献，搜索用时 46 毫秒
1.
晁拥军 《温州职业技术学院学报》2001,1(2):38-39
本通过对渗硼层显微组织和性能的分析及渗硼后试件耐磨性的试验，研究了自保护膏剂渗硼及复合热处理工艺对工件耐磨性的影响。结论是：自保护膏剂渗硼后，进行不同温度复合热处理，表面高硬度的硼化组织与不同种类的基体组织结合，所表现出的耐磨性是不同的。 相似文献
2.
TiAl基合金的密度低、强度高、高温蠕变性能好,在航空航天、汽车、船舶领域有着广泛的应用.但是TiAl基合金在一些特殊介质中如酸、盐溶液中容易被腐蚀,为了解决此问题,常常需要对其进行一定的表面处理.本文对TiA基合金进行双层辉光等离子铌碳复合渗处理渗技术,对复合渗后试样(记作TiAl-Nb-C)合金层组织成分进行分析,同时,研究其在不同腐蚀介质中的电化学腐蚀行为,绘制阳极极化曲线,并和原TiAl基材的腐蚀极化曲线进行比较分析. 相似文献
3.
耿在丹 《河南广播电视大学学报》1997,(4)
不同原始组织对渗硼层深度的影响耿在丹提要：本文研究了不同原始组织对渗硼层深度的影响规律，确定了较佳的原始组织，并对不同原始组织影响渗硼的机理进行了初步探讨。关键词：渗硼，原始组织，渗层深度。１引言渗硼是改善金属材料表面性能的一种行之有效的方法，其适用... 相似文献
4.
李海斌张晓波石林爽张曼婷 《福建工程学院学报》2021,(4):360-364
采用固体渗剂包埋渗法对Ti-6Al-4V钛合金进行硼-稀土共渗处理,并利用超声振动空蚀机研究分析试样在去离子水中的空蚀性能。结果表明,硼-稀土共渗在Ti-6Al-4V合金表面获得均匀致密的表面渗层。表面渗层具有很高的显微硬度,与基体冶金结合,其主要由TiB2、TiB化合物层和B原子固溶于α-Ti的扩散层构成。稀土元素La的添加,提高渗硼效率,使试样表面渗层厚度增加,显微硬度显著提高,材料的抗空蚀性能得到显著改善。 相似文献
5.
《赣南师范学院学报》2014,(3):34-36
首先对铸态AZ91D镁合金进行固溶处理,然后通过直径φ6mm、φ10mm和φ20mm的钢球对其进行表面机械研磨强变形处理.采用光学显微镜(OM)、透射电镜(TEM)以及高分辨透射电镜(HRTEM)等表征了AZ91D镁合金表面强变形微观结构.结果表明:表面机械研磨处理后,AZ91D镁合金组织发生明显变化,表层最细晶粒尺寸可达20 nm,变形层组织呈梯度变化,钢球直径对表层机械研磨处理试样组织影响明显,小径钢球晶粒细化效果不明显,大径钢球则不能覆盖整个处理表面. 相似文献
6.
本文以安全阀中提动阀(材料CCr15)为研究对象,就其经淬火回火、渗硼、渗钒、钒硼共渗等不同工艺热处理后的耐磨性进行了试验比较,并结合组织、性能对它们的磨损过程进行了初步探讨。 相似文献
7.
本文讨论了稀土元素对模具钢渗硼的一些影响,渗硼后显微硬度的分布规律,表明了渗硼后工件表面有着极高的硬度,良好的耐磨性。稀土元素的加入对催渗作用的影响存在着一个最佳值。 相似文献
8.
亚表面损伤的精确表征有助于全面掌握光学元件研磨后的亚表面损伤特征,是确定后续抛光时间和加工程序、提高研磨加工效率的切实依据.该文首先从目前比较常见的几种亚表面损伤测试技术出发,简要阐述各种测试技术的实验原理,综合实验结果分析了各种方法对亚表面损伤表征的研究状况,并对截面法在K9光学玻璃亚表面损伤方面的应用进行了实验对比研究,对比分析了研磨粒径与裂纹最大深度间的关系. 相似文献
9.
李春波 《赤峰学院学报(自然科学版)》2013,(23):99-100
系统论述了稀土复合渗硼的最新研究进展,分析了渗硼的热力学基础,稀土渗硼的机理研究,稀土复合共渗以及渗硼零件的组织与性能研究。为以后的进一步研究具有重要的指导意义． 相似文献
10.
应用光学显微镜、显微硬度计和分析天平，研究了45钢在固体硼铬稀土共渗后的组织和性能。结果表明：硼铬稀土共渗改善了渗层组织，而且温度、保温时间、稀土浓度的变化对渗层组织都有较大的影响。 相似文献
11.
罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
12.
Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
13.
Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F. 相似文献
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15.
陈美曦 《山东教育学院学报》2008,23(2):103-107
Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language. 相似文献
16.
邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
17.
《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
19.
Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
20.
Anton Franks 《English in Education》1999,33(2):39-49
This paper looks at the way drama works to bring a model of an arts curriculum into reality. He also shows how drama is valuable when discussed as a separate, autonomous subject in the school curriculum as opposed to one subsumed within English. He argues for a view of the arts and gives an example of a sequence of work in an English GCSE class based around Arthur Miller's play View from the Bridge. From this he draws out several strands about the relationship of the drama curriculum to the individual students and teachers, the school, and to culture. He also emphasises the primacy of performance in drama education. 相似文献