Fe_(83)Ga_(17)La_x合金的磁致伸缩性能及组织研究

用真空电弧熔炼法制备Fe_(83)Ga_(17)La_x(x=0,0.2,0.4,0.6,0.8)铸态合金,采用震动样品磁强计、透射电镜、能量分散光谱仪、光学显微镜和自制磁致伸缩测量设备研究不同La含量对Fe_(83)Ga_(17)合金磁性能以及组织结构的影响。结果表明,添加La明显增加了合金的磁致伸缩性能,其中Fe_(83)Ga_(17)La_(0.2)的磁致伸缩系数最高可达210×10~(-6)。La易在晶界处富集,随着La含量增加,合金晶粒尺寸逐渐减小。La有助于合金沿100取向的晶粒增多。     

首次报道PrFe2稀土合金中的巨磁致伸缩以及自旋再取向等效应

南京大学唐绍龙教授课题组唐妍梅博士利用稳态强磁场实验装置(SHMFF)的X射线衍射仪设备(XRD),开展了具有立方Laves相结构的PrFe2合金研究并取得了新的进展,首次报道了PrFe2稀土合金中的巨磁致伸缩以及自旋再取向等效应。理论预言,具有Laves相的PrFe2合金在低温(0K)下具有5600 ppm的磁致伸缩效应,具有潜在的应用价值。但     

Tb0.3Dy0.7(Fe1-xAlx)1.95合金显微组织及低磁场的磁致伸缩性能研究

研究了Al添加量变化对Tb0.3Dy0.7(Fe1-xAlx)1.95合金显微组织、磁致伸缩系数的影响.结果发现,随着Al添加量的增加,晶体显微组织中的析出物增加;在一定的磁场强度下,磁致伸缩系数随Al添加量而变化,当磁场强度低于40kA/m时,磁致伸缩系数随Al添加量的变化曲线出现一峰值,当磁场强度高于40kA/m时,磁致伸缩系数随Al添加量的增加而降低.     

合金成分对Tb_xDy_(1-x)Fe_(1.91)磁致伸缩性能影响的研究

为了研究TbDyFe合金成分的变化对合金磁致伸缩性能的影响,采用真空感应熔炼炉制备四种Tb_xDy_(1-x)Fe_(1.91)(x=0.22、0.27、0.3、0.35)合金棒,然后取铸态性能较好的试棒真空定向凝固,将定向凝固后的试棒进行真空热处理,测试合金棒的磁致伸缩性能,分析合金中的组织取向,研究材料中的显微组织。研究表明,在低磁场下x=0.27的试样比其他三组实验得到的样品的磁致伸缩性能好,高磁场下x=0.3的样品磁致伸缩性能好而且"jump"效应明显,且定向凝固后的不同取向组织比例对试样的磁致伸缩性能影响很大。组织中的大尺寸富稀土相的产生对合金磁致伸缩性能影响很大。铸态性能较好的Tb_(0.27)Dy_(0.73)Fe_(1.91)合金,在真空环境下热处理后,稀土元素氧化烧损较多,磁致伸缩性能下降剧烈。合金基体主要的相为RFe_2与RFe_3耦合相,烧损导致合金的成分偏离,造成包晶RFe_2相和初生RFe_3相的耦合生长。     

微量稀土元素Tb、La掺杂对Fe-Al合金结构和磁致伸缩性能的影响

为了研究微量稀土元素Tb和La掺杂对Fe81Al19合金结构和磁致伸缩性能的影响及影响机制,采用真空电弧熔炼法制备了Fe81Al19、Fe81Al19La0.1和Fe81Al19Tb0.1三种铸态合金。用X射线衍射仪(XRD)和扫描电镜联合能谱仪(SEM/EDS)分析了合金的微结构。用振动样品磁强计(VSM)和磁致伸缩测量仪测试了合金的磁性能和磁致伸缩系数。结果表明,Fe81Al19合金由单一的bcc结构A2相组成,而掺杂稀土后的Fe81Al19Tb0.1和Fe81Al19La0.1合金均由bcc结构的A2主相和少量富稀土相组成。稀土Tb和La的掺杂使Fe81Al19合金沿<100>晶向择优取向,且Fe81Al19Tb0.1合金择优取向更加明显。此外,三种合金的磁化功大小排序为:Fe81Al19Tb0.1> Fe81Al19La0.1> Fe81Al19。表明稀土元素掺杂导致Fe-Al合金具有更大的磁晶各向异性,且Tb的掺杂效果更加明显。磁致伸缩系数测试表明,与Fe81Al19合金相比,稀土掺杂合金的磁致伸缩系数明显增大,而且Fe81Al19Tb0.1合金的磁致伸缩系数增大的更加明显,大约是Fe81Al19合金的3.2倍,为86×10^-6。稀土掺杂合金磁致伸缩系数增大的原因主要源于掺杂稀土使Fe-Al合金沿<100>晶向择优取向和稀土导致合金具有高磁晶各向异性。     

Tb0.3Dy0.7(Fe1-xAlx)1.95合金显微组织及低磁场的磁致伸缩性能研究

研究了Al添加量变化对Tb0.3Dy0.7(Fe1-xAlx)1.95合金显微组织、磁致伸缩系数的影响。结果发现,随着Al添加量的增加,晶体显微组织中的析出物增加;在一定的磁场强度下,磁致伸缩系数随Al添加量而变化,当磁场强度低于40kA/m时,磁致伸缩系数随Al添加量的变化曲线出现一峰值,当磁场强度高于40kA/m时,磁致伸缩系数随Al添加量的增加而降低。     

Tb对Fe81Ga19快淬合金薄带组织和磁致伸缩性能的影响

利用快淬甩带方法制备了Fe81Ga19Tbx(x=0,0.2,0.4,0.6)合金薄带,研究了合金薄带的显微组织结构和磁致伸缩性能。实验结果表明,Fe-Ga-Tb合金薄带的显微组织及磁致伸缩性能与合金的成分密切相关,合金薄带基体为Fe(Ga)无序固溶相体。Fe81Ga19Tb0.2合金的磁致伸缩系数最大,达到-1320×10-6,且薄带厚度方向[100]择优取向,Tb在晶界处富集。     

激光多普勒准静态法测量磁致伸缩系数

提出了一种利用激光多普勒测量磁致伸缩系数的方法,理论分析了激光多普勒测量磁致伸缩系数的工作原理,设计了铁镓合金棒材的测试系统.对铁镓合金棒(Galfenol)的准静态磁致伸缩系数进行测量.结果显示,该方法所获得应变与出厂数据符合较好,在10 Hz驱动电流下获得铁镓合金棒的动态变化曲线.该测量方法具有以下优势:(1)能够实现非接触测量;(2)可以测量铁镓合金棒端面任意点的应变情况;(3)测量结果准确度较高;(4)测量操作简单.      

金属玻璃(Fe_(1-x)Co_x)_(78)Si_(10)B_(12)的磁致伸缩随退火的变化

研究了金属玻璃(Fe_(1-x)Co_x)_(78)Si_(10)B_(12)(x=0,0.1,0.5,0.7,0.9和1)的饱和磁致伸缩常数λ_s随退火的变化。在晶化之前,退火对x≥0.9的合金的λ_s影响很小,其余合金的λ_s可提高(1.5～4.8)×10~(-6);初期晶化的退火使λ_s向相应多晶Fe_(1-x)Co_x的中场磁致伸缩值靠近。     

真空烧结温度对WC-TiC-TaC-Co硬质合金组织和性能的影响

采用高能球磨、真空烧结工艺制备WC-13(TiC+TaC)-8Co-1(VC+Cr3C2)硬质合金,研究了不同烧结温度对WC-TiC-TaC-Co硬质合金微观组织、力学性能和磁性能的影响。结果表明,提高烧结温度有利于提高合金的致密度,但是过高的烧结温度会导致晶粒长大,使合金致密度下降;合金的硬度、抗弯强度和矫顽力随着真空烧结温度的提高先增大后减小;相对磁饱和强度随着烧结温度的升高呈现下降的趋势;1 400℃烧结的合金综合性能较好,合金的相对密度99.6%、抗弯强度1 992 MPa,硬度92.3 HRA,矫顽力34.3 k A/m,相对磁饱和强度为76.5%。     

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。     

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。     

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.     

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。     

Effect of antibiotics of chemotaxis of human leukocytes

The effect of 20 different antibiotics on chemotaxis by human neutrophils was studied. Human leukocytes incubated with chloramphenicol, rifampin, sodium fusidate, and tetracyclines in vitro showed markedly depressed migration. The mechanisms by which these antibiotics affect leukotaxis are discussed.