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文中对用Zn空心阴极灯作光源测定Cu与Cu空心阴极灯测定Cu,用Cd空心阴极灯作光源测定Ag与Ag空心阴极灯测定Ag,用Ca空心阴极灯作光源测定Mg与Mg空心阴极灯测定Mg,进行了比较实验研究。通过实验发现,可以用Zn空心阴极灯代替Cu空心阴极灯测定Cu,用Cd空心阴极灯代替Ag空心阴极灯测定Ag,用Ca空心阴极灯代替Mg空心阴极灯测定Mg;其测定检出限相近、精密度高。用国家地球化学标准样品GBW0 7401(GSS-1)、GBW0 7311(GSD-11)进行验证,其准确度较好。 相似文献
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通过对真空炉双层空心轴工作的受力分析及研究,发现双层空心轴在工作过程中承受静载荷的同时主要承受弯矩和扭矩的作用,从而找到了双层空心轴断裂的原因。在满足双层空心轴的强度、刚度和使用性能要求的前堤下,提出了解决措施。 相似文献
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本文讨论了空心微粉铁、铜基复合材料的组织和性能。试验结果初步表明,空心微粉铁、铜基复合材料的力学性能优于基体材料的力学性能,为空心微粉复合材料的开发应用开辟了一个新领域。 相似文献
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本文讨论了空心微粉铁、铜基复合材料的组织和性能。试验结果初步表明,空心微粉铁、铜基复合材料的力学性能优于基体材料的力学性能,为空心微粉复合材料的开发应用开辟了一个新领域。 相似文献
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空心微珠热碱液活化化学镀银 总被引:1,自引:0,他引:1
将空心微珠在HF和NaF的缓冲液中进行粗化处理,然后用75℃热碱液活化,再以甲醛为还原剂,在空心微珠表面化学镀银。通过扫描电镜(SEM),X射线能量色散谱仪(EDS)和X射线衍射(XRD)对所得复合粉体的表面形貌、成分以及镀层与空心微珠的结合强度进行研究与分析,并探讨pH值对沉积效果的影响。结果表明:粗化处理可增大空心微珠的表面粗糙度,从而提高Ag+的形核能力,所得镀层完整、致密。镀液pH升高,包裹层更完整、致密,且银层增厚。在pH=12.9的条件下,可实现银层对空心微珠均匀、致密的包裹,得到镀层结合强度较高、银层较厚、银晶粒尺寸为23.3nm的银包空心微珠复合粉体。 相似文献
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K Ohta M Nishi M Ueda S Ohyama T Matsubara T Takahashi T Nakajima 《Canadian Metallurgical Quarterly》1998,99(9):589-594
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. 相似文献
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A Dragni? 《Canadian Metallurgical Quarterly》1977,24(2):167-175
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. 相似文献
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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。 相似文献
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A Duquette S Kérouac BK Sandhu P Saulnier L Lachance 《Canadian Metallurgical Quarterly》1997,22(2):257-278
The purpose of this study was to verify a model of relationships between psychosocial factors and health for 8066 francophone nurses working in geriatric care in Québec. A random sample of 1990 subjects was drawn and a participation rate of 77.9% and 55% was obtained for the two-time study taken twelve months apart. Based on the theory of Maddi and Kobasa (1984), the model was reproduced for the two-time periods with the aid of structural equations. The analyses showed that three variables exert a direct influence on psychological distress: professional burnout, occupational stressors and hardiness. Also, variables have a direct effect on burnout: listed in order of importance, these are hardiness, occupational stressors, work support, active strategies of coping and employment status. In dealing with the work stressors, the nurses who are hardy make use of active strategies of coping and look for support form their colleagues. The results of the study help to better understand the psychological and social resources that best favor adaptation of working women in highly demanding work environments. The fallout of the study converges towards the quality of life of helping professionals and towards the cost and quality of health and social services. 相似文献
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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". 相似文献
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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. 相似文献
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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。 相似文献