太钢第二炼钢厂顶底复吹转炉工艺生产实践

太钢第二炼钢厂通过引进钢铁研究总院的“长寿复吹转炉炼钢工艺技术”,将2号、3号顶吹氧气转炉改造为顶底复吹转炉。总结阐述了改造后复吹转炉终点碳氧积、脱磷、脱碳、造渣和吹炼等各项工艺的研究。     

国内外转炉炼钢技术的新进展

回顾了转炉炼钢三次技术进步的历程,叙述了转炉炼钢工艺技术的开发、分类及主要冶金特点,介绍了世界复吹转炉工艺技术的应用情况,提出相关钢厂应研发少渣炼钢工艺、复吹转炉高效吹炼技术和吹炼终点动态控制的三项建议.     

转炉炼钢熔池碳含量动态变化研究

通过引入炉气分析仪采集的实测数据,用碳指数模型描绘熔池内碳含量实时变化趋势,并用修正后的碳积分模型计算转炉吹炼过程的总脱碳量,以对碳含量的动态变化和终点出钢情况做出预报.在机理分析的基础上,利用三阶段脱碳曲线的后期变化趋势建立碳指数实时和终点预报模型,同时对碳积分计算公式加以修正,得到冶炼全程的脱碳率计算模型.仿真结果表明,碳指数及碳积分模型直接用于指导转炉炼钢生产具有一定的参考价值,在一定程度上可以取代炉气分析仪的使用.     

减少渣量的转炉工艺研究与实践

通过对转炉前期倒渣时机和吹炼工艺参数的研究,开发了一种减少渣量的转炉炼钢工艺.该工艺的转炉吹炼过程分2个阶段,分别是脱磷期和脱碳期,脱磷期结束后倒除部分富磷渣,然后进行小渣量脱碳,吹炼终点保留脱碳渣用以下一炉脱磷.实践结果表明:与常规冶炼工艺相比,减少渣量操作工艺的转炉石灰消耗由26 kg/t降至17 kg/t以下,轻烧白云石消耗由13kg/t减少到9 kg/t以下,降低了转炉生产成本;吹炼终点钢水w(P)控制在0.0080％～0.018 2％,平均为0.012 6％.     

基于副枪控制的转炉终点预测模型

利用转炉吹炼末期脱碳指数方程、热平衡和热力学方程分别建立了转炉终点碳、温度、磷和锰的预报模型.终点碳质量分数预报误差为±0.015%的命中率达到87.6%;转炉终点目标w(C)=0.03%时,温度误差范围±10 ℃的比率为85.4%;模型预报钢中w(Mn)误差在±0.02%、w(P) 误差在±0.003%范围的比率分别达到了87.0%和81.2%.建立的预报模型具有较高的精度,实现了转炉终点碳、温度、残锰和磷的同时预报,为提高转炉的终点控制命中率、减少补吹的次数、实现直接出钢打下良好的基础.     

基于投掷式探头的转炉终点自动控制技术的应用

利用投掷式探头模拟副枪进行钢水测量,同时改进静、动态模型,实现了100 t转炉无副枪、无烟气分析自动炼钢技术。应用结果表明,终点双命中率提高到90.82%,补吹率由投运前的平均28.3%减少到6.76%,金属消耗降低,吹炼过程平稳,喷溅减少。同时还建立了终点低磷的吹炼模型,转炉的脱磷率达90%以上,平均出钢磷质量分数控制在0.010%~0.015%左右。     

转炉炼钢生产技术的发展

总结了近几年国内铁水脱硫预处理、转炉复合吹炼与炉外精炼等主要炼钢生产工艺技术的进步.分析讨论了目前国内炼钢生产中存在的主要技术问题.进一步提出国内炼钢生产应研究开发少渣冶炼工艺、复吹转炉高效吹炼技术和吹炼终点动态控制技术等项重大共性技术.     

氧气顶吹转炉智能控制策略的研究

在全面分析转炉炼钢生产特点的基础上,建立了神经元网络的预报模型和控制模型,并且将炼钢的终点温度和终点碳含量作为控制目标值,计算氧气的补吹量和冷却剂的补入量,进而实现转炉炼钢的终点控制。从计算机仿真结果看,终点温度和终点碳含量仿真精度高,控制策略有效。     

转炉炼钢模型脱碳系数的研究

分析了承钢150 t转炉炼钢动态控制模型的理论基础,引入了脱碳系数,研究了脱碳系数与液面高度、底吹流量和造渣量的关系,提出通过脱碳系数的调整可实现炼钢模型与终点碳含量的精确控制。     

基于函数型数字孪生模型的转炉炼钢终点碳控制技术

由于转炉冶炼过程中的热力学和动力学反应复杂,副枪控制模型和传统的烟气分析模型存在很大的局限性,导致了转炉冶炼终点碳含量的预测精度偏低,是实现智能炼钢的主要技术瓶颈. 针对上述问题,提出了基于烟气分析的炼钢过程函数型数字孪生模型. 首先,利用烟气分析得到连续监测的实时数据,以此来实时监控转炉熔池内钢水的碳氧反应状态; 然后,根据熔池反应所处的不同阶段,利用函数型数据分析方法建立吹炼前期和吹炼后期的函数型预测模型; 在此基础上,按照吹炼前期和吹炼后期这两个阶段来分别自动修正模型中的系数函数,从而能在复杂的实际工况条件下完成对熔池碳含量的准确预测. 通过260 t氧气转炉的工业应用实例,证实函数型数字孪生模型具有良好的自学习和自适应能力,对异常冶炼状态具有良好的鲁棒性,可以实现全过程的熔池碳含量动态预测,终点碳质量分数在± 0. 02% 范围内的命中率为95%. 利用函数型数字孪生模型在拉碳阶段对钢水中碳含量的预测值来控制终吹点. 更为重要的是,在保证入炉原料成分、温度、质量等参数稳定的前提下,采用该模型可以有望取消基于副枪的停吹取样步骤,从而降低生产成本,提高产品质量和生产效率,具有广泛的工业应用前景.      

Voices of fear and anxiety and sadness and depression: The effects of speech rate and loudness on fear and anxiety and sadness and depression.

Two studies investigated the role of expressive vocal behavior (specifically, speech rate and loudness) in fear and anxiety and in sadness and depression. In the 1st study, participants spoke about personally experienced fear and anxiety-arousing and neutral events using 3 different voice styles: fast and loud, normal, and slow and soft. In the 2nd study, participants spoke about personally experienced sad or depressing and neutral events using the same 3 voice styles. In both studies, the participants' highest levels of subjective affective and cardiovascular (CV) arousal occurred when they spoke about the emotional events in a mood-congruent voice style: fast and loud in the case of fear and anxiety, and slow and soft in the case of sadness or depression. Mood-incongruent voice styles canceled the heightened levels of CV arousal normally associated with these negative emotions. The voice-style manipulation had no significant effect on the participants' levels of CV arousal during the neutral discussions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sexuality and aging--usual and successful

BACKGROUND: As aging research increasingly reflects an effort to dissociate true time-driven changes from those that can be improved, sexuality in later life remains largely unexplored. Several problems are evident. There is a lack of normative data, a lack of a conceptual framework relating to the biology, psychology, and sociology of sex, and an attitudinal resistance that obscures the entire topic. METHODS: We conducted a three-part instructional series on major topics involved with sexuality and aging. We surveyed our group of attendees (n 158, average age 68 for males, 65 for females) before and after the series. RESULTS: A remarkably robust sex life was evidenced by both the men and the women, even until advanced old age. Yet, a substantially decreased involvement was reported from 10 years earlier. Despite current activities, people of both sexes wished they were participating even more than they currently were. Impotency was identified as the major negative feature for the men; relationship problems were for the women. A questionnaire 6 months after the series reported improved sexual attitudes, but no change in sexual activities from the earlier survey. CONCLUSION: Sexuality is a major quality-of-life issue which persists into old age. Our study showed that the usual sexual practices reported by our group were not considered by them to be ideal. The intervention of this instructional series provided improved sexual attitudes but not performance. Additional studies are encouraged.     

Spondylolysis and spondylolisthesis and sports

Spondylolysis and spondylolisthesis occur predominantly in the lower lumbar spine. Besides congenital defects such as predisposition of spondylolysis the correlation between competitive sports activities and an increased incidence of spondylolysis is proved. In early stages, complete healing can be achieved by conservative treatment (abstinence from sports activities for 3 months, orthesis). Persistence of pain, neurologic symptoms and progression of vertebral slipping are indications for operative treatment (reconstruction of the isthmus, dorso-ventral spondylodesis). The exercise tolerance depends on the extent of instability, progression of vertebral slipping and clinical symptoms. The limits of exercise tolerance vary among the individual athletes and require the decision of the physician. Backstroke swimming, abdominal and back muscle strengthening exercises, and types of sport involving smooth movements are advisable. Sports education in school is possible without restriction in patients with stable spondylolysis and in those with spondylolisthesis without unfavourable concomitant factors.     

Synthesis and analysis of mixed chlorinated-fluorinated dibenzo-p-dioxins and dibenzofurans and assessment of formation and occurrence of the fluorinated and chlorinated-fluorinated dibenzo-p-dioxins and dibenzofurans

Despite the use of multimodal therapy, higher-grade glioma is still uniformly fatal in the adult population. There is a considerable difference between the length of survival in each given patient, even within the same tumor type and malignancy grade group, suggesting that there are factors that might differentially influence outcome. To identify such factors, 107 patients with anaplastic or malignant glioma were retrospectively investigated. Clinical parameters and paraclinical data on the p53, mdm2, and EGFR genes at the DNA or protein level were evaluated by univariate analysis and Cox proportional hazards regression modeling. Kaplan-Meier survival estimation demonstrated that immunohistochemical positivity for mdm2 protein in patients with anaplastic astrocytoma or with glioblastoma multiforme was associated with a shorter survival time (p = 0.02). P53 gene mutations and immunopositivity for the epidermal growth factor receptor (EGFR) protein were not significantly related to poor prognosis. The Cox proportional hazards model revealed immunohistochemical positivity for p53, mdm2, or for both of them, the presence of postoperative irradiation, and the extent of surgical resection of tumor to be variables significantly associated with prolonged survival. EGFR overexpression, age over 60 years, and Karnofsky performance score below 40 points did not significantly shorten survival time. In conclusion, the present study identified immunohistochemically detected mdm2-protein overexpression as a statistically significant negative prognostic parameter in patients bearing anaplastic or malignant glioma. Association analysis of variables revealed a possible correlation between mdm2 and p53, which is also consistent with the biological interaction mode of both proteins in vivo.     

Larks and owls and health, wealth, and wisdom

OBJECTIVE: To test the validity of Benjamin Franklin's maxim "early to bed and early to rise makes a man healthy, wealthy, and wise." DESIGN: Cross sectional analysis of sleeping patterns in a nationally representative group of elderly people, and longitudinal investigation of mortality. SETTING: Eight areas in Britain (five in England, two in Scotland, and one in Wales). SUBJECTS: 1229 men and women aged 65 and over who in 1973-4 had taken part in a survey funded by the Department of Health and Social Security and for whom data on sleeping patterns, health, socioeconomic circumstances, and cognitive function had been recorded. MAIN OUTCOME MEASURES: Self reported income, access to a car, standard of accommodation, performance on a test of cognitive function, state of health and mortality during 23 years of follow up. RESULTS: 356 people (29%) were defined as larks (to bed before 11 pm and up before 8 am) and 318 (26%) were defined as owls (to bed at or after 11 pm and up at or after 8 am). There was no indication that larks were richer than those with other sleeping patterns. On the contrary, owls had the largest mean income and were more likely to have access to a car. There was also no evidence that larks were superior to those with other sleeping patterns with regard to their cognitive performance or their state of health. Both larks and owls had a slightly reduced risk of death compared with the rest of the study sample, but this was accounted for by the fact that they spent less time in bed at night. In the study sample as a whole, longer periods of time in bed were associated with increased mortality. After adjustment for age, sex, the presence of illness, and other risk factors, people who spent 12 or more hours in bed had a relative risk of death of 1.7 (1.2 to 2.5) compared with those who were in bed for 9 hours. The lowest risk occurred in people who spent 8 hours in bed (adjusted relative risk 0.8; 0.7 to 1.0). CONCLUSION: These findings do not support Franklin's claim. A "late to bed and late to rise" lifestyle does not seem to lead to socioeconomic, cognitive, or health disadvantage, but a longer time spent in bed may be associated with increased mortality.     

Craniometaphyseal and craniodiaphyseal dysplasia, head and neck manifestations and management

Mechanical allodynia (MA) following hand injury is a well-documented clinical problem. The purpose of this pilot study was to examine the relationship between hand MA and the upper limb tension test (ULTT). The ULTT mechanically stresses the neural structures from the C5/6/7 neural foramina to the median nerve distally. This study examined 29 subjects with unilateral hand MA before and after a 2-week neural self-mobilization programme. There was a significant difference between the subjects' affected and unaffected sides when tested using the ULTT, both in reproduction of symptoms and in reduced range of motion of the ULTT. Following the self-mobilization program, there was an improvement in the range of the ULTT, and subjects reported a reduction in their symptoms. Complete recovery was not obtained in all cases. The results of this study suggest that the ULTT is a useful tool both in assessment and treatment of subjects with hand MA.     

Intralesional and topical chemotherapy and immunotherapy

This article covers the principles and applications of radiation therapy in horses. The goal in treating tumors by irradiation is tumor control with minimum treatment complications. Various treatment techniques are available to achieve this goal. The prognosis depends on many factors such as the extent and location of the tumor, tumor type and tumor cell proliferation. Radiation therapy is a very effective treatment modality for equine tumors but logistical reasons limit its impact in equine oncology.