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高炉铁水沟浇注料的抗渣性及耐冲刷性是延长铁水沟使用寿命的重要手段。以刚玉、Si C、α-Al2O3微粉和球状沥青为主要原料,制备了铁水沟浇注料,主要研究碳化硅对浇注料物理性能,尤其是抗渣性的影响。结果表明:在碳化硅加入量不变的情况下,粒度越小,材料的抗氧化性能和烧后强度均提高,认为320目的碳化硅较为合适;粒度相同时,碳化硅加入量不同对材料性能产生影响,认为加入10%的碳化硅能够得到适宜的物理性能和良好的抗渣性能。 相似文献
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反射炉采用高铝碳化硅不烧砖,使用寿命有较大的提高。高铝碳化硅不烧砖具有良好的耐高温性和耐冲刷性,具有良好的热震稳定性和烧后产生微膨胀性能,并且生产工艺简单,可降低成本、节约能耗、提高效率、提高效益、扩大使用范围。 相似文献
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高文义 《有色金属材料与工程》2006,27(2):27-31
碳化硅砖和碳化硅砖与普通碳砖复合侧块,在上世纪末期我国铝电解槽上开始推广应用。使用后各厂家普遍发现碳化硅砖及碳化硅砖与普通碳块复合侧块均出现不同程度的断裂、上抬和脱落现象,该文对断裂、上抬和脱落原因进行了分析,并提出了改进措施。 相似文献
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仲钨酸铵中钠,钾析出条件及机理研究 总被引:1,自引:0,他引:1
以现代化学结晶理论为依据,研究了APT结晶过程中钠、钾的析出规律。结果表明,提高钨酸铵溶液起始WO_3浓度、降低APT结晶率、提高结晶温度和缩短时间,降低搅拌强度均能不同程度地降低钠,钾含量。降低结晶器比面积能较大程度地降低APT中钾含量。洗涤对减少钠含量较有效。试验条件下测得钾的有效分配比C_s/C_l=0.18~0.55,钠的有效分配比C_s/C_l=0.016~0.059。 相似文献
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《山东冶金》2016,(6)
以莫来石、红柱石为主要原料,加入不同含量的氮化硅、碳化硅细粉,探讨了添加氮化硅对莫来石碳化硅材料性能的影响。结果表明:在1 450℃下制备的材料的显气孔率基本维持在15%左右,体积密度在2.45 g/cm~3左右,烧后线变化率相差不大,高温抗折强度和荷重软化温度也分别能够达到29.8 MPa和1 560℃,都表现出了较高的水准,且基本不受氮化硅加入量的影响;添加氮化硅能够提高材料的抗热震性能,但材料的常温耐压强度随着氮化硅含量的增加呈降低趋势;材料在烧结过程中,氮化硅和碳化硅均发生了氧化并在材料表面形成一层黄褐色氧化产物,其主要为玻璃相;在材料的截面出现致密层,且致密层的厚度随着氮化硅含量的增加而减小。 相似文献
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《稀有金属》2015,(4)
以碳化硅微粉作为原料,并选用Al2O3、高岭土和Mg O作为烧结助剂,同时选用羧甲基纤维素钠(CMC)、聚丙烯酰胺(PAM)和可溶性淀粉作为添加剂,通过有机泡沫浸渍法制备出莫来石/碳化硅复相泡沫陶瓷材料。研究了不同原料组成、不同烧结温度等工艺参数对所制备的莫来石/碳化硅复相泡沫陶瓷物相组成、微观结构的影响,同时对莫来石/碳化硅复相泡沫陶瓷的孔隙率、力学性能进行了测试。研究结果表明:莫来石/碳化硅复相泡沫陶瓷的微观结构控制主要受碳化硅含量的影响,随着碳化硅含量的增加,莫来石/碳化硅复相泡沫陶瓷的孔隙率有明显的降低,但抗压强度随之提高;随着烧结温度的提高,孔棱的致密度增加,抗压强度亦显著提高;莫来石/碳化硅复相泡沫陶瓷的最佳烧结温度为1600℃,陶瓷粉料中最佳的Si C含量为35%。在1600℃烧结温度下,碳化硅的含量为35%时,获得了孔隙率为76.19%和抗压强度为4.63 MPa的莫来石/碳化硅复相泡沫陶瓷。 相似文献
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TA Solokhina LS Shevchenko IuV Se?ku EG Rytik LV Besedina TS Veshchugina 《Canadian Metallurgical Quarterly》1998,98(6):42-46
Usage of quality of life of psychiatric patients' relatives as the parameter of estimation of the quality of psychiatric care is considered. By means of standard questionnaire elaborated by the authors as well as by means of both individual and group conversations the quality of life was analyzed in 40 relatives which lived together with psychiatric patients. Different spheres of their life and difficulties (financial, social-psychologic, production) were examined in families with such patients. The defects of psychiatric care that had direct influence on the quality of life of the psychiatric patients' relatives are outlined. 相似文献
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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. 相似文献
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显微维氏硬度测量不确定度评定 总被引:1,自引:0,他引:1
对显微维氏硬度测量不确定度进行评定,建立了不确定度计算的数学模型,确定了影响实验结果的各项因素,计算出了各因素的标准不确定度,得出结果的扩展不确定度,并给出最终测量结果的表达式。 相似文献
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G Steinbach 《Canadian Metallurgical Quarterly》1997,110(7-8):247-250
Totally negative results of epidemiological investigation of random samples do not prove the absence of the infection as the pathogen may be restricted to only a few animals in the herd for a long time. The statement "absence of infection" is critical for such situations. The question is raised, whether the statement "absence of infection" should be generally avoided. Classification of herds and flocks according to the prevalence of the pathogen would be more valid for the implementation of control measures. 相似文献
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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) 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