Ce对Al-Ni-Zr合金的非晶形成能力及力学性能的影响

加入Ce部分取代Al84Ni10Zr6合金中的Zr,用单辊旋淬法制备Al84Ni10Zr6-xCex(x=0~6,%)合金,利用X射线衍射、差示扫描量热和纳米压痕等试验分析方法研究Ce取代Zr对Al84Ni10Zr6合金的非晶形成能力及力学性能的影响。结果表明,用Ce代Zr可有效抑制α-Al、Al3Ni等初生晶体的形成,提高合金的非晶形成能力、显微硬度和弹性模量。x=0时,Al84Ni10Zr6合金具有完全晶体结构,显微硬度和弹性模量都较低。x=1~5时,合金具有晶体+非晶复合结构,增加Ce含量,则初生晶体相减少,合金的显微硬度和弹性模量提高。x=6时,Al84Ni10Ce6合金具有完全非晶态结构,显微硬度和弹性模量最高,分别达到4.29和94.99 GPa。x≥3时,合金出现明显的玻璃转变现象,过冷液相区ΔTx为11~16 K,约化玻璃转变温度Trg为0.46~0.48。     

Nb含量对Zr55Cu30Ni5Al10块体金属玻璃热稳定性和力学性能的影响

在水冷铜坩埚中采用铜模吸铸法制备出直径Ф3 mm的(Zr0.55Al0.10Ni0.05Cu0.30)100-xNbx(x=0,2,4,6,8,10)合金试样,利用X射线衍射(XRD)、差热分析(DSC)、扫描电镜(SEM)以及准静态压缩试验方法研究了Nb含量对Zr55Cu30Ni5Al10块体金属玻璃的非晶形成能力、热稳定性、力学性能和组织的影响。研究结果表明,添加适量的Nb元素能提高Zr55Cu30Ni5Al10合金的热稳定性和非晶形成能力。当Nb含量为x=8时,合金具有最宽的过冷液相区(ΔTx=86 K)和最大的非晶形成能力(参数γ=Tx/(Tg+Tl)=0.416)。对于Zr55Cu30Ni5Al10合金,优化Nb元素掺杂量可以获得最佳的非晶形成能力和热稳定性。Nb的适量添加也有利于提高Zr55Cu30Ni5Al10块体金属玻璃的压缩断裂强度和塑性变形能力,其中x=8时,合金的压缩断裂强度和塑性应变量分别达到1877MPa和1.92%,并具有加工硬化现象。     

Al-Co-Y合金系非晶的形成及其晶化过程

利用熔体快淬法制备出了Al92-xCo8Yx（x=4,6,8,9,10）薄带,采用X射线衍射（XRD）和扫描电镜（SEM）进行结构分析,示差扫描量热仪（DSC）进行热稳定性分析。研究了Y的加入对合金的非晶形成能力的影响以及Al84Co8Y8合金薄带等温退火的晶化过程。结果表明：当Y的原子分数为8%时,合金系的非晶形成能力最好;非晶态Al84Co8Y8合金的晶化过程分为3个阶段进行,退火过程中的组织结构转变为：非晶合金→非晶基体＋初晶α-Al＋少量未知亚稳相→α-Al相＋未知亚稳相＋Al9Co2→α-Al相＋Al9Co2相＋Al3Y相。     

机械合金化MlNi_(3.55)Co_(0.75)Mn_(0.4)Al_(0.3)/Mg复合储氢合金的相结构和电化学性能

采用机械合金化法制备了MlNi3.55Co0.75Mn0.4Al0.3+x%Mg(Ml=富镧混合稀土;x=3,5,7,10)复合储氢合金。利用X射线衍射和电化学测试方法对MlNi3.55Co0.75Mn0.4Al0.3铸态合金和MlNi3.55Co0.75Mn0.4Al0.3/Mg复合合金的相结构和电化学性能进行了研究。X射线衍射结果发现,MlNi3.55Co0.75Mn0.4Al0.3合金由单一的La Ni5相组成。而MlNi3.55Co0.75Mn0.4Al0.3/Mg复合合金由La Ni5主相和小量的(La,Mg)2Ni3相组成,且合金中(La,Mg)2Ni3相的含量随镁含量x的增大而增多。此外,当复合合金中镁含量较多(x=10)时,复合合金有非晶化的趋势。电化学性能测试结果发现,当添加镁含量较少(x≤7)时,合金的最大放电容量、放电性能以及循环稳定性都好于MlNi3.55Co0.75Mn0.4Al0.3合金的相应性能,其中x=5时,合金的综合电化学性能最佳。合金电化学性能的改善得益于合金中形成恰当比例的La Ni5和(La,Mg)2Ni3相。     

微量元素Y、Ag对Cu基非晶合金玻璃形成能力的影响

采用单辊旋淬法制备了Cu50Zr42Al8,Cu46 Zr47-xAl7Yx(x=2,5),Cu43Zr42AlsAg7和Cu43Zr42Al8Ag5 Y2非晶合金薄带,利用X射线衍射和差示扫描量热分析研究了合金样品的玻璃形成能力和热稳定性.结果表明,在Cu50Zr42Al8中添加适量的Ag、Y后使得非晶合金的短程有序结构发生改变.合金Cu46Zr47-xAl7Yx(x=2,5)的过冷液相区宽度ΔTx分别比Cu50 Zr42 Al8增加了19K、30K,约化玻璃转变温度Trg从0.565分别增加到0.579和0.566,参数γ从0.402分别增加到0.418和0.420,说明Y的添加提高了非晶合金的热稳定性和玻璃形成能力.合金Cu43Zr42 Al8Ag7和Cu43Zr42Al8Ag5Y2与Cu50Zr42Al8相比,约化玻璃转变温度Trg及参数γ均有了明显的提高,达到了0.619、0.416和0.609、0.411,表明Ag的添加、Ag和Y的同时添加均提高了Cu - Zr -Al系非晶合金的玻璃形成能力,但Ag的效果更加显著.     

锆基大块非晶合金的非等温晶化动力学效应

采用非等温差示扫描量热法(DSC)研究了锆基非晶合金Zr60Al15Ni25、Zr65Al10Ni10Cu15的晶化动力学.结果显示,随着升温速率的加快,这两种非晶合金的特征温度Tg、Tx、Tp均向高温区移动,且过冷液相区逐渐加宽,表明非晶合金的玻璃化转变和晶化均具有动力学效应.分别采用Kissinger法和Ozawa法计算各非晶合金的激活能,两种方法的计算结果相近.从激活能数据得出,两种锆基非晶合金的热稳定性均较强;与非晶合金Zr60Al15Ni25相比,Zr65Al10Ni10Cu15虽较难形成玻璃化转变和开始晶化,但其晶化一旦开始则随后的过程反而更容易进行.     

Al88Ni4Y6Er2非晶合金动力学性能

采用单辊旋淬法制备了Al88Ni4Y6Er2非晶合金,用X射线衍射(XRD)、差示扫描量热(DSC)测试手段研究了Al88Ni4Y6Er2非晶合金晶化过程中的动力学性能.发现Al88Ni4Y6Er2非晶合金晶化温度Tx与升温速率φ通过Vogel-Fulcher-Tammnann公式拟合后满足非线性关系.并根据Tx10≈Tk这种近似关系,求得Al88Ni4Y6Er2非晶合金的Kauzmann温度Tk为401 K,由此推断出VFT温度T0不大于401 K.     

A_2B_7型La_(0.64)Gd_(0.2)Mg_(0.16(1+x))Ni_(3.1)Co_(0.3)Al_(0.1)储氢合金微观组织和电化学性能

以综合电化学性能较佳的低镁含量合金La0.64Gd0.2Mg0.16Ni3.1Co0.3Al0.1为基础,通过改变Mg元素含量的添加方式,用感应熔炼方法与热处理制备了La0.64Gd0.2Mg0.16(1+x)Ni3.1Co0.3Al0.1系列合金,系统研究了该条件下镁元素成分波动(Mg过量值x)对La-Mg-Ni系A2B7型合金微观结构和电化学性能的影响规律。合金相结构分析表明,合金退火组织由主相Ce2Ni7(Gd2Co7)型以及Pr5Co19型、Pu Ni3型和Ca Cu5型多相组成,随Mg过量值x增加,合金中主相Ce2Ni7型相丰度呈现先增加后减小的趋势;当Mg过量值0x≤50%时,合金组织的Ce2Ni7型主相相丰度达到81.04%~87.18%;x=0,80%时,Ce2Ni7型主相丰度减小至76.3%以下。电化学测试结果表明,随Mg过量值x增加,合金电极最大放电容量呈先增加后降低趋势,x=10%时合金具有最高电化学放电容量(384.6 m Ah·g-1);当Mg过量值x在5%~50%范围内变化时,其电极循环稳定性均保持在S100≥90%,此时镁元素成分波动变化对合金电极循环稳定性的影响不敏感。合金电极的高倍率放电性能(HRD)随Mg过量值的增加呈先增大后减小趋势,其中电极表面的电荷转移速率是影响合金电化学反应动力学性能的主要控制步骤。     

铜镍合金化及半固态处理工艺对ZrCoAl系非晶合金组织的影响

向以Zr80Co15Al5为基体的非晶合金中添加微量铜和镍,利用铜模吸铸法和半固态处理工艺制备棒状(Zr0.88Cu0.12)95-2x Al5(NiCu)x(x=1.5、2.5、3.5)非晶合金。利用SEM、XRD和光学显微镜(OM)分析研究了半固态处理工艺对非晶合金的微观组织结构、玻璃形成能力及断口形貌的影响。结果表明,在半固态处理工艺基础上对Zr80Co15Al5添加微量铜和镍后有较好的晶体形成能力。     

Co含量对La0.55Pr0.05Nd0.15Mg0.25Ni3.5-xCoxAl0.25（x=0～0.4）储氢合金电极性能的影响

采用电磁感应悬浮炉制备La0.55Pr0.05Nd0.15Mg0.25Ni3.5-xCoxAl0.25(x=0,0.1,0.2,0.3,0.4)系列合金,研究Co含量对合金的相结构、吸放氢性能和电化学性能的影响。研究结果表明,该系列合金主要由LaNi5、Nd2Ni7相组成。当Co含量大于0.2时,合金中出现La2Ni7相。压强-吸氢量-温度(Pressure-Content-Temprature)测试显示在303 K温度下,合金具有良好的吸氢性能,当x=0.4时合金的最大吸氢量为1.29(质量分数,%)。电化学测试表明:随x值变化,合金电极的最大放电容量分别为340.0(x=0.0)、346.6(x=0.1)、370.0(x=0.2)、320.0(x=0.3)和346.6(mA.h)/g(x=0.4);随Co含量增加,合金电极容量保持率不断增加,高倍率放电性能先增加后减小,循环伏安曲线、氢在合金体中的扩散系数D共同反映了合金电极的动力学特性。     

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.