延长倾动炉稀氧燃烧炉寿命的研究及应用

贵冶倾动炉稀氧燃烧技术的应用,使得炉内温度呈现明显的梯度分布,造成烧嘴区、渣线区、精炼侧风管区、加料门周围区域耐火砖损耗加剧。通过对燃烧器改进、工艺参数优化、风管位置调整、渣线区喷补等措施,使得炉况好转,从而达到延长倾动炉炉寿命的目的。     

转炉超音速氧枪喷头磨损后的吹炼特性变化

 转炉氧枪喷头会随枪龄的增加发生不同程度的侵蚀,为了探究氧枪喷头侵蚀程度对超音速气体射流吹炼特性的影响,建立了120 t转炉及超音速氧枪的三维全尺寸几何模型,研究了氧枪喷头不同磨损角度对气体射流特性、熔池速度及壁面侵蚀的影响。发现随着磨损角度增加,射流速度衰减加快,射流核心区长度缩短,同一等速线长度缩短,射流中心最大速度和最大速度点距中心距离增大。射流动压衰减速度随磨损角度增加而加快,磨损角度由0增至20°,距喷头端面1.5 m处最大动压减小了14.84%,14 000 Pa等压线包围面积由0.038 m2减小至0.002 m2。钢液面处高速区面积随着磨损角度增加而减小,死区面积随着磨损角度增加而增大。熔池纵截面高速区域主要分布在冲击凹坑和底吹元件附近,低速区域主要分布在熔池底部,死区主要分布在熔池底部中心和炉壁下部区域。当熔池深度小于0.6 m时,顶吹气流对熔池的搅拌起主要作用,磨损角度增加,熔池搅拌能力变弱,熔池横截面高速区面积减小,低速区和死区面积增大;当熔池深度大于0.6 m时,底吹气流对熔池搅拌起主要作用,高速区面积基本不变。渣-金作用区域和底吹流股附近流体湍动能较大、壁面剪切应力较为集中,该部位耐火材料侵蚀严重。熔池壁面附近流体湍动能和壁面剪切力随磨损角度增加而降低,转炉炉衬侵蚀速度减小。     

不同型号镁碳砖对抗富钒钢渣侵蚀性能的影响

目前,提钒转炉采用镁碳砖作为炉衬,评估不同型号镁碳砖的侵蚀速率以及损毁机理对提高提钒转炉寿命具有重要的实用价值。在电阻炉条件下,采用静态抗渣方法模拟6种镁碳砖侵蚀情况,探讨镁碳砖抗富钒钢渣侵蚀及其机理。结果表明,MT-C12B、MT-C14A试样受熔渣冲刷、侵蚀后减薄较少,其中MT-C12B试样侵蚀面积所占比例为2.98%,MT-C14A试样侵蚀面积所占比例为2.74%。从试样侵蚀情况显微结构看,MT-C12B试样的脱碳层深度最小,对镁碳砖性能影响较小,为提钒转炉最优选择。6种镁碳砖侵蚀机理基本一致,镁碳砖中的石墨与钢渣中的V₂O₃、Cr₂O₃、FeO反应生成金属相,造成MgO颗粒的裸露,渣中V₂O₃随熔渣进入脱碳层并与在此处的MgO反应,在镁碳砖表面形成含钒尖晶石相(MgV₂O₄);另外,液态渣相中的SiO₂、CaO等与MgO颗粒反应生成新的低熔点液渣相,进而完成方镁石的溶解过程。含钒尖晶...     

热应力对高炉炉缸和炉底侵蚀的影响

为了探讨热应力对不同材质构成的高炉炉缸砖衬的破坏作用,在计算温度场的基础上,应用热弹性理论和有限元法对高炉炉缸进行应力分布计算。计算结果表明：在用具有不同的导热性能和力学性能的耐火材料砌筑的炉缸内存在着应力集中现象,这是导致高炉炉缸破损的主要原因之一。     

南钢1号高炉炉衬侵蚀原因分析

南京钢铁厂一号高炉在1984年11月17日大修后投产开炉。炉容300m~3。至1987年的下半年炉基温度就超过650℃,几次加钒钛料护炉,对炉基温度及炉缸水温差上升有所控制,1989年元月进行了不换炉衬的中修,开炉后炉基温度继续回升,1989年6月炉身上     

鞍钢高炉炉缸异常侵蚀的原因及对策探析

对鞍钢近年来高炉炉缸破损调查情况进行了阐述。从炉缸侵蚀的状况来看,铁水环流、炭砖应力破坏、化学氧化侵蚀和炭素胶泥的质量不合格是鞍钢高炉炉缸异常侵蚀的主要原因。另外,基于对炉衬侵蚀原因和特征的分析,提出了应从设计、制造与施工、烘炉、开炉和日常生产操作等方面采取有措施,以延长高炉炉缸使用寿命。     

钙处理低合金高强钢连铸过程中塞棒侵蚀机理及其改进

针对钙处理低合金高强钢浇铸过程中塞棒的异常侵蚀问题,通过对塞棒基质层和侵蚀层进行成分分析、物相分析以及元素分布观察,并进行热力学计算分析,探究了塞棒的侵蚀机理,并提出了相应的改进措施.结果表明,钢液中过量的钙与塞棒耐火材料中的Al2 O3、SiO2在塞棒界面反应生成CaO,进而与塞棒耐火材料中的Al2 O3、SiO2反...     

关于11号高炉长寿达标的几个问题

11号高炉改造性大修后投产以来,炉体侵蚀严重,相当于长寿(10年)高炉3年的侵蚀量,其原因主要是①炉况、热制度波动,不能形成稳定的渣皮,使保护层或粘附物脱落而产生“热震”,导致耐火材料因热应力引起断裂、剥落;②冷却系统的冷却效率低;③炉墙热负荷过大或控制不当。因此,应当采取相应措施加以维护,减少高炉操作的波动因素,开发并应用高炉长寿技术,加强综合治理等等。这样,11号高炉的长寿化目标是完全可以达到的。     

水泥回转窑及其内衬的侵蚀

介绍了水泥回转窑的发展及其工艺特点,以及对其内衬材料的要求.针对回转窑不同内衬材料,详细分析了杂质元素、化合物对耐火材料的侵蚀作用.     

浅谈“卷草沟—杉木箐”平坑混凝土侵蚀原因及其处理

本文结合矿山实例,对坑道衬砌加固混凝土的侵蚀原因、侵蚀来源以及处理原则及方法进行了分析与探讨。对于如何防止混凝土侵蚀现象的发生、发展,维护坑道安全提出了一些具体措施。     

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.     

Quality of life of relatives of mental patients

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.     

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。     

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.     

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。     

Stability of hydrophobic nuclei of protein molecules depending of the degree of packing

The values of free energies for the formation of hydrophobic cores with different degree of packing of nonpolar side chains have been calculated. It has been shown that the difference between the values of free energy for tightly packed cores inaccessible to water solvent molecules and the values of free energies for less tightly packed hydrophobic cores whose surface is in contact with the water solvent, is 50-60 kJ/mol and coincides with the value of the enzyme free energy change during its interaction with the substrate.     

Synthesis of algorithms of control over the process of decomposition of nickel tetracarbonyl

Construction of an automated control system over the process of decomposition of nickel tetracarbonyl is considered. Confidence intervals of the obtained first-order and second-order models are analyzed. A model is described that allows one to compensate for the influence of perturbing factors and mutual influence of control effects on neighboring regions. Based on the algorithm presented, it is possible to construct an adaptive system of automated control over the process of decomposition of nickel tetracarbonyl.     

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.