温度对CVD制备Ti-Si-C涂层中Ti_3SiC_2形成规律的影响

采用TiCl4-CH3SiCl3-H2-Ar反应体系,低压化学气相共沉积(LPCVD)Ti-Si-C三元体系涂层。采用XRD、SEM、EDS和EPMA分析在1 100~1 250℃不同温度下制备的涂层物相组成和形貌结构。结果表明:1 100℃时形成TiC涂层,无Ti3SiC2相;1 150~1250℃时形成TiC与Ti3SiC2复合涂层。当沉积温度为1 200℃时,Ti3SiC2晶粒沿?104?方向择优生长,而在1150℃和1 250℃沉积时,择优取向不明显。1150℃时涂层为多孔细柱和颗粒堆积嵌合结构,当温度为1 200~1250℃时,涂层分为两层,内层过渡层为柱状晶结构,主要成分为TiC;外层为TiC相与Ti3SiC2相复合的板条错堆状结构。     

沉积温度和碳纳米管对CVD SiC涂层微观形貌的影响

以三氯甲基硅烷(CH3SiCl3)为前驱体,采用化学气相沉积法(Chemical vapor deposition,CVD),在原位生长有碳纳米管(Carbon nanotubes,CNTs)的C/C复合材料表面制备SiC涂层。用扫描电镜(SEM)和X射线能谱仪(EDS)观察和分析涂层微观形貌及成份。研究沉积温度(1 000~1 150℃)对SiC涂层的表面、截面以及SiC颗粒的微观形貌的影响。结果表明:在1 000℃下反应时,得到晶须状SiC;沉积温度为1 050℃时涂层平整、致密;沉积温度提高到1 100℃时,涂层粗糙,致密度下降;1 150℃下形成类似岛状组织,SiC颗粒团聚长大,涂层粗糙,并有很多裂纹和孔洞,致密度低。对涂层成份和断口形貌研究表明,基体和涂层之间有1个过渡区,SiC涂层和基体之间结合良好。     

低Ca/P比溶液电沉积羟基磷灰石涂层

电沉积羟基磷灰石涂层具有工艺简单、过程易控制、适于在复杂表面制备厚度均匀涂层的特点.沉积液的Ca/P比直接影响涂层中的物相组成与涂层形貌.作者采用电沉积与后续热处理相结合的工艺,用低Ca/P比溶液在金属钛表面沉积羟基磷灰石(HA)涂层.利用X射线衍射仪、透射电镜和扫描电镜分析涂层中物相组成及后续热处理对涂层中物相和涂层形貌的影响.结果表明:随电压与温度的升高,涂层中羟基磷灰石含量增加;空气中500℃热处理后,涂层基本转化为羟基磷灰石,其Ca/P比约为1.61;热处理前,涂层由块状和条状物质组成;热处理后,涂层形貌并未改变,它由纳米颗粒的HA凝聚烧结而成.     

平行电极表面磁场对电沉积钴-镍镀层的影响

在硫酸盐体系中电沉积钴-镍合金, 采用X射线能谱分析和扫描电镜研究pH值、阴极电流密度以及外加平行于阴极表面磁场对镀层组成、表面形貌的影响. 发现增大电流密度或者pH, 钴-镍合金的沉积速率增大、所得镀层中的钴含量减少, 镀层表面的晶粒粒径增大. 外加平行于电极表面的磁场可以略微提高沉积速率和电流效率以及使所得镀层表面均匀, 晶粒细小. 采用X射线衍射研究在镀液pH 3.0下阴极电流密度和外加磁场对所得镀层结构的影响. 结果表明, 电沉积钴-镍合金镀层呈六方密堆积（hcp）的（100）和（110）晶面择优取向;外加平行于电极表面的磁场可以促进（110）晶面择优生长和抑制（002）晶面择优生长.     

C/C复合材料硅化物涂层形貌及结构

采用料浆烧结法在1450℃温度下烧结制备了C／C复合材料硅化物高温抗氧化涂层，通过XRD和SEM分析涂层结构及相组成，并对涂层形成机理及涂层氧化前后的结构和形貌变化进行了研究。结果表明：在C／C复合材料表面生成了以MoSi：为主、含部分SiC的两相硅化物主体层，同时在主体层和基体间生成SiC过渡层，保证了涂层与基体的良好结合；涂层在1500℃下氧化生成SiOz玻璃膜，阻挡了氧向基体内部的扩散；氧化过程中Si元素的扩散导致涂层内部微裂纹增多，同时SiC过渡层厚度增加。     

化学气相沉积ZrO_2涂层的表面微观形貌演变

采用ZrCl4-CO2-H2-Ar体系,在不同温度或氢气流量条件下采用常压化学气相沉积法(APCVD)通过不同沉积流程在C/C样品表面制备ZrO2涂层。用X射线衍射分析仪(XRD)和扫描电镜(SEM)分析涂层的物相组成和形貌特征。结果表明:随沉积温度升高,ZrO2涂层表面形貌由小颗粒堆积态向大尺寸多晶转变;氢气流量为0时,只在局部区域出现了少量ZrO2,当氢气流量为400mL/min时,ZrO2涂层晶粒尺寸较大且晶体学平面特征最明显;在氢气流量为800mL/min时沉积出现了副产物ZrC与C;在氢气流量为1600mL/min时,出现沉积副产物ZrC;连续沉积时,得到的ZrO2涂层为山峰状形貌。     

CVD温度对钽涂层组成、显微组织及形貌的影响

利用TaCl2-H2-HCl反应体系,采用冷壁式化学气相沉积法(CVD)在钼基体表面沉积钽涂层。通过X射线衍射仪、金像显微镜及扫描电镜等手段,对不同沉积温度下钽涂层的组成、组织及形貌进行了研究。结果表明:在1000～1300℃范围内,钽沉积层的相组成无变化,而对择优生长有一定影响;钽沉积层晶粒尺寸随沉积温度的升高而增大;钽沉积层表面颗粒呈金字塔形多面体且随沉积温度的升高而增大。     

高温热蒸发法在金刚石表面镀覆SiO_2的形貌与形成机理

采用高温热蒸发法在金刚石表面镀覆SiO_2,用扫描电镜(SEM)、X线衍射(XRD)和能谱分析对SiO_2的形貌与物相组成进行观察与分析,研究SiO_2晶体的生长机制。结果表明,在较低温度下(1 300℃)金刚石表面生成SiC和SiO_2颗粒,无法形成涂层。温度升高到1 400℃时,金刚石表面形成许多由C,Si,O元素组成的细小蝌蚪状组织。当温度升高到1 500℃时,金刚石表面镀覆良好的Si-O涂层,Si-O涂层上有许多SiO_2晶粒、微米棒与晶须。SiO_2晶体的生长机制为:首先在金刚石表面沉积一层Si-O涂层,然后在该涂层上析出SiO_2颗粒,在SiO_2颗粒上进一步形成新的SiO_2颗粒和晶须。     

Ar气流量对石墨表面CVD TaC涂层生长与表面形貌的影响

用C3H6作为碳源气,Ar作为稀释气体和载气,TaCl5为钽源,采用化学气相沉积法(chemical vapor deposition,CVD)在高纯石墨表面制备TaC涂层。采用X射线衍射(XRD)和扫描电镜(SEM)等对涂层进行表征,研究1 000℃下稀释气体(Ar)流量对TaC涂层成分、织构及表面形貌的影响。结果表明:随着稀释气体流量增大,表面均匀性和光滑度提高,晶粒尺寸减小,晶体择优取向降低,沉积速率减小,涂层中C含量增多。当稀释气体流量为100 mL/min时,TaC涂层晶粒尺寸与沉积速率分别为32.5 nm和0.60μm/h;而当稀释气体流量增大到600 mL/min时,涂层晶粒尺寸与沉积速率分别下降到21 nm和0.25μm/h。     

PVD溅射电流对SiC纤维表面Ti_3Al涂层组织结构的影响

采用磁控溅射物理气相沉积(PVD)法在SiC纤维表面进行Ti3Al涂层的制备,研究了该过程中PVD溅射电流对Ti3Al涂层组织结构的影响规律。通过X射线衍射(XRD)、扫描电子显微镜(SEM)和原子力显微镜(AFM)对Ti3Al涂层的沉积率、组成物相、晶粒大小、组织结构和表面形貌等进行了观察与分析。研究结果表明,磁控溅射PVD法制得的Ti3Al涂层组成物相与靶材一致,但涂层生长择优取向发生了变化。随着溅射电流的增大,Ti3Al涂层沉积率提高,平均晶粒尺寸增大。此外,涂层的微观形貌为柱状晶组织,但随着溅射电流的增加,涂层表面因粒子溅射辐照温度的升高而升温,同时晶粒边界出现迁移,涂层生长由V型柱状晶生长向等轴柱状晶生长转变,最后形成致密组织。涂层粗糙度的变化与涂层晶粒尺寸和微观结构有关,因此Ti3Al涂层表面粗糙度随着溅射电流增加呈现出先增大后减小的规律。     

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。     

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.     

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.