添加微量锆、铒对铸造Al-8.25Zn-2.4Mg-2.3Cu合金组织与力学性能的影响

采用光学显微镜、扫描电镜和X射线衍射等方法研究了微量Er和压元素对Al-8.25Zn-2.4Mg-2.3Cu合金铸锭组织的细化作用及其细化机制,同时考察了微合金化元素对试验合金力学性能的影响.结果表明:单独添加Zr对Al-8.25Zn-2.4Mg-2.3Cu合金铸锭组织有一定的细化作用,而复合添加Zr和Er则对Al-8.25Zn-2.4Mg-2.3Cu合金铸锭组织产生强烈的细化效果,分析表明其细化效应与合金凝固过程中Al8Cu4Er相、Al3Er相和Al3Zr等复合质点的析出及微量元素在凝固界面前沿的富集有关.经过T6处理,Al-8.25Zn-2.4Mg-2.3Cu-0.18Zr-0.40E哈金的抗拉强度σb为600 MPa;延伸率达到8%.与7075合金相比,试验合金的强度与塑性均获得大幅度提高.     

Mg-6Al-1Zn-Y镁合金组织及力学性能的研究

在Mg-6Al-1Zn合金的基础上添加不同质量分数的Y（分别为0％，0．5％，0．9％，1．4％），制备了4种实验合金，研究了Y的添加对合金组织性能的影响。通过X射线衍射、金相显微镜、扫描电镜、电子探针等手段分析了Mg-6Al-1Zn合金添加Y后组织结构的变化。研究结果表明，添加了不同含量Y的合金中都出现了一种新相Al2Y相。随着Y含量的增加，Al2Y相数量增多而Mg17Al 12相则减少。Y能细化合金铸态及挤压态显微组织，其细化作用在添加了0．9％Y的镁合金中尤为明显。铸态合金室温拉伸试验表明：该合金具有最佳的综合力学性能。当Y含量添加至1．4％时，Al2Y相变得粗大且出现团聚现象而导致了拉伸性能的下降。经过挤压后，合金的力学性能大幅度上升。     

微量钪(Sc)对5A01合金性能与显微组织的影响

研究了在5A01合金基础上添加0．2％Sc和0．3％Sc后合金的显微组织、力学性能、腐蚀性能及焊接性能。结果表明，微量Sc的加入，初生Al3Sc或Al3（Sc，Zr）粒子可成为有效的非均质晶核，大大地细化合金的铸态晶粒，次生Al3Sc或Al3（Sc，Zr）粒子，能有效地钉轧位错和亚晶界，稳定亚结构并强烈抑制合金的再结晶。因此，加入Sc后的试验合金基体及焊接强度提高，腐蚀性能和焊接性能与5A01合金相当甚至更好。     

退火对Al-Mg-Mn-Zr-Er合金冷轧板组织与性能的影响

制备了Al-6.0Mg-0.7Mn-0.1Zr-0.3Er合金冷轧板材,并对板材进行了不同退火温度和不同退火时间的退火试验,测试退火处理后的合金显微硬度,并采用TEM对合金显微形貌进行分析.结果表明:合金在低于250℃退火时,主要发生回复现象,合金再结晶起始温度为250℃,再结晶终了温度为325℃,且在175℃长时间退火合金易于沿胞状组织的胞壁析出Al3Mg2相.合金中复合添加Er和Zr形成细小弥散的Al3 (Er,Zr)质点,与基体共格,可钉扎位错,稳定亚结构,阻碍亚晶长大及晶界的迁移,从而抑制合金的再结晶,提高合金的热稳定性.     

添加微量稀土元素对Sn-Ag-Cu系无铅焊料性能的影响

以Sn-3．0Ag-0．5Cu（质量分数，％）焊料为母合金，探讨了微量稀土元素Ce、Er、Y和Sc对Sn—Ag—Cu合金物理性能、润湿性能以及力学性能的影响。试验结果表明：稀土元素对焊料的性能有不同的影响，添加微量Ce元素可以更好地改善焊料综合性能。     

Nd对Mg-11Li-3Al-2Zn-0.2Zr合金组织、力学性能及腐蚀行为的影响

研究稀土Nd对均匀化态Mg-11Li-3Al-2Zn-0.2Zr合金组织、力学性能及腐蚀行为的影响.通过真空感应熔炼制备镁锂合金铸锭, 经均匀化处理(280 ℃, 24 h)得到均匀化态Mg-11Li-3Al-2Zn-xNd-0.2Zr(x=0, 0.5, 1.0, 1.5)合金.采用XRD和SEM分析合金的显微组织, 并对合金进行拉伸试验和断口分析.采用电化学法和析氢失重法研究合金在3.5 %NaCl溶液中的腐蚀行为.结果表明:Mg-11Li-3Al-2Zn-0.2Zr合金主要含有β-Li、AlLi、MgLi₂Al相, Nd的加入使合金中形成NdAl3相.随着Nd含量的增加, 合金的强度和塑性呈先增大后降低的趋势. Mg-11Li-3Al-2Zn-1Nd-0.2Zr合金表现出较优的力学性能, 其抗拉强度和延伸率相对于Mg-11Li-3Al-2Zn-0.2Zr合金分别提高了28.8 %和51.3 %.稀土Nd的添加使合金的耐蚀性能提高.      

Al-4.9Zn-1.6Mg-0.4Mn-0.1Zr-xEr合金时效行为研究

采用金相(OM)、透射电镜(TEM)及能谱分析(EDS)、硬度测试的方法研究了单级与双级时效热处理制度对Al-4.9Zn-1.6Mg-0.4Mn-0.1Zr-xEr合金板材硬度和显微组织的影响.结果表明,添加Er元素后合金中形成了纳米级的A13(Zr,Er)相,可以强烈地钉扎位错,细化再结晶晶粒.无论单级时效还是双级时效,Er元素的添加均可以提高合金的硬度,加快合金的时效硬化速率,使合金达到硬度峰值的时间缩短,但Er含量对提高合金硬度的影响不大.同时,晶界处出现的第二相颗粒析出带得到消除,合金中存在明显的沉淀无析出带.此外,Er元素可以促进Zn,Mg元素的固溶,而析出的A13(Zr,Er)颗粒又可以促进MgZn2相的析出.     

微量Nd和Sc对A1-6．5Mg-0．5Mn合金组织及力学性能的影响

采用拉伸力学性能测试、扫描电镜及透射电镜观察等手段研究了微量Nd和Sc对Al-6．5Mg-0．5Mn合金的显微组织及力学性能的影响。结果表明：分别单独添加Nd,Sc使合金的抗拉强度均有所提高;同时添加Nd和Sc可使合金的抗拉强度、屈服强度分别提高65MPa、55MPa,但合金的伸长率有所降低;合金中晶界上形成含Nd或Sc的化合物,这些化合物钉扎亚晶界、从而抑制合金的再结晶晶粒的形成。     

合金成分和挤压工艺对5A02合金棒材组织和力学性能的影响

研究了复合添加微量元素Zr和Er对5A02合金棒材组织及力学性能的影响,优化制定了合金的化学成分及挤压工艺。试验结果表明,添加的主合金元素Mg、Mn含量在标准范围的中低限,可将合金挤压棒材R状态的抗拉强度控制在225MPa以下;复合添加微量元素Zr和Er,能够明显降低5A02合金挤压棒材的粗晶环深度;优化制定的挤压工艺,可显著提高生产效率。     

高强高阻尼Mg-Zr系合金的研究(Ⅱ)——热挤压及退火对Mg-Zr-(Ca/Y)合金组织和性能的影响

研究了三种Mg-Zr系阻尼合金（Mg-0．6Zr．Mg-0．6Zr-0．3Ca，Mg-0．6Zr0．3Ca-0．1Y）住热挤压及退火后组织和性能的变化。结果表明：合金在热挤压过程中晶粒明显细化．使力学性能得到提高。三种合金在铸态下，其阻尼性能随应变振幅的增加而不断提高；经过热挤压后，阻尼性能明显下降，且几乎与应变振幅无关；挤压后的退火处理又使合金阻尼性能有所增大．但与铸态时仍存在一定差距。在各处理状态下，Mg-0．6Zr-0．3Ca和Mg-0．6Zr-0．3Ca-0．1Y合金的力学性能明显高于Mg-0．6Zr合金，而阻尼性能在铸态下与Mg-0．6Zr合金相差不大，但经热挤压和退火后有较大差距。三种合金阻尼性能随处理状态的变化可用Granato-Liicke值错模型解释。     

转炉炉壳热应力分析

根据实际转炉建立实体模型。以有限元为手段,考虑了炉衬和炉壳材料的物性参数随温度变化的特点和炉衬与炉壳之间膨胀间隙,计算了转炉炉壳在温度载荷和炉衬膨胀压力同时作用下的热应力。所得结果可为转炉炉壳设计提供依据。     

The effect of amount of possession of the trait of hostility on accuracy of perception of hostility in others.

Some theories of personality hold that an individual's perception of others is influenced by his own personality characteristics; more specifically, that a trait of low social value will be projected more into others, and that insight into the possession of these characteristics reduces this distortion. These 2 hypotheses were tested by having a group of college students rate each other (including themselves) on degree of friendliness or hostility. Agreement with group rating about self yielded the insight score. In general, the hypotheses were supported; the "friendly" Ss were most accurate in their perception of others, and insight was positively associated with accurate perception. From Psyc Abstracts 36:04:4HL16M. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of rates of infection of two methods of emergency ventricular drainage

The rates of infection of two methods of external ventricular drainage in use at Atkinson Morley's Hospital--namely, (a) percutaneous drainage with Rickham reservoirs and (b) tunnelled ventriculostomies--were compared in this retrospective review. Percutaneous drainage of CSF with Rickham reservoirs was associated with a 27% rate of infection as identified by positive microbiological cultures; tunnelled ventriculostomy catheters had a 10% infection rate. The difference in the infection rate between the two methods was statistically significant (P < 0.015). Other variables examined, including the age and sex of the patients and the reasons for ventricular drainage, were not associated with an increased rate of infection. Most infections from either method were caused by a coagulase negative staphylococcus. The average duration of ventricular drainage before identification of positive cultures was 5.7 days for Rickham reservoirs and 6.0 days for ventriculostomies.     

浅析《野草》的版画特征

鲁迅先生一生热爱美术作品,对版画中木刻兴趣尤甚.<野草>作为其"写心之作",亦呈现出一些与木刻版画一致的审美特征:一是具有木刻版画的色彩特征,多对比、多冷色,有阴郁的美感;二是具有木刻版画的力度特征,环境描写、人物刻画处处刀锋毕现,遒劲有力,有一种"力之美".     

四辊破碎机车刀架的改造

针对四辊破碎机车刀架车削中存在的几个问题,详细介绍了电动车刀架的结构和工作原理,建立主要设计参数的数学表达式,并进行适当的分析。改造后,这种电动车刀架运行平稳、可靠、方便、省力,取得了预期的效果。     

Results of treatment of cancer of the cardia

Cancer of the cardia is traditionally discussed with cardiac cancer of the lower portion of the esophagus and upper gastric cancer invading the esophagus, and the specific characteristics of cancer of the cardia have never been clearly defined. We reviewed the outcome of 172 patients with adenocarcinoma of the cardia who had undergone radical surgery between 1949 and 1994 in the Division of Gastrointestinal Surgery of the Cancer Institute Hospital. The centers of the tumors were located within 2 cm above and below the boundary between the esophagus and the stomach, and their longitudinal diameter was less than 8 cm. We divided the patients into an early period (1949-1979; n = 79) and a late period (1980-1994; n = 93), and focused on the historical transition. There were no differences in patient gender or histology between the two periods. However, the late period was associated with fewer cases of esophageal invasion and shorter longitudinal diameter, as the age of the population advanced. The number of advanced cancers such as the localized and infiltrative type had decreased, and early cancer and early clinical stage had become more common, but despite the fact that the number of early cancers had increased, extended dissection, such as thoracic and paraaortic lymph node dissection, was performed more frequently. By clinical stage, the long-term outcome markedly improved in Stage I patient in the late period, and tended to improve in Stage II and III patients. This appears to have been attributable to the prevention of micrometastasis by extended dissection, although the number of early cancers is another major potential cause. There were no differences in the outcome of Stage IV patients between the two periods, and further advances in multimodality therapy must be awaited. The range of resection is basically proximal gastrectomy, and if there are adequate indications, the prognosis is favorable. In view of the status of lymphatic flow and lymph node metastasis, and long-term results, lateroaortic lymph node dissection is important. Since the number of early cancer patients has been increasing, if intraabdominal recurrence is prevented, intrathoracic lymph node dissection will contribute greatly to the outcome of such patients.     

焦炭热性能指标意义浅析

通过对焦炭在高炉内的历程及其变化规律的剖析,阐述焦炭热性能指标的意义,形象地把焦炭在高炉内的损耗分为三部分(M1,M2,M3)。指出M2对焦比及焦炭价格有一定的指导作用。     

Comparison of the results of surgical and conservative treatment of fractures of the diaphysis of the tibia

In this paper is treated the fundamental problematic of the fracture of the diaphysis of the tibia and the therapeutic results after the conservative and operative treatment are confronted. Among 518 patients with 433 open fractures and 35 with closed fractures of the diaphysis of the tibia, successful treatment of more 2/3 was obtained in the period from 1968 to 1972. Following our casuistics and literature, whose results are similar, we find out that the average total treatment of the osteosynthesis of the fracture of the diaphysis was shortened for 2,5 months depending upon the type and the localisation of the fracture. Apolied methods of the operative and conservative and conservative treatment in relation to the velocity of the medical cure as well as to the extreme anatomical-functional results are analised. We noticed that osteosynthesis, made by the intermedullary nail and the extension of the canals or by a small AO table, by the achieved stability makes conditions of immediate motions and an early rehabilitation. Because of that it gives the best functional results.