国内外高炉炼铁技术的进步

本文叙述了近年来国内外高炉炼铁技术的进步,其主要表现在高炉沿着大型化、高效化、自动化方向前进;重视原料工作;发展高炉(?)控制技术(包括无钟炉顶结构和控制技术和矿焦技术和矿焦混装布料技术),(?)行“五高一低”的冶炼技术等等。     

承钢1260m~3高炉低成本冶炼研究

高炉冶炼过程中的入炉焦比和燃料比高低是衡量高炉能否获得优良技术经济指标的重要参数,本文以承钢1~#高炉(1260m~3)为研究对象,根据高炉的实际生产现状,分析研究降低承钢高炉入炉焦比的途径,论述高炉操作、技术管理与节焦降耗之间的关系。从生产数据出发,对承钢高炉节焦降耗情况进行对比分析,通过不断优化操作制度,探索出承钢高炉节焦降耗的操作技术,使承钢高炉人炉焦比大幅度的降低,为企业带来巨大的经济效益。     

浅谈高炉中心加焦

通过对鞍钢１１号高炉中心加焦前后生产指标的对比，论述了中心加焦技术的理论依据和作用，并结合１１号高炉的实际指出了实施中心加焦技术应注意的问题。     

高炉中心加焦

本文论述了高炉中心加焦的一般原理,着重介绍了塔拉索夫钟式炉顶中心加焦技术和扎波罗什钢厂高炉中心加焦的生产实践。     

高炉脱湿鼓风技术

高炉鼓风中由于湿度是不断波动的,会对高炉操作及顺行带来影响.采用脱湿鼓风技术可以稳定鼓风中的水分含量,使高炉操作稳定、顺行,达到节焦、增产的效果,并为提高喷煤量创造了条件.介绍了适合采用脱湿鼓风的高炉生产条件以及脱湿方法的选择和节焦增产的效果.     

高炉中心加焦模拟试验

本文论述了高炉中心加焦模拟试验,试验以1:1的模型试验,测定了焦炭中心落点的高度和炉料的落下轨迹,中心加焦溜槽设计问题,并预测包钢2号高炉,采用中心加焦技术可增产2％。     

锰铁高炉采用脱湿鼓风效果探讨

本文在概述国内外生铁高炉脱湿鼓风技术发展和脱湿鼓风对高炉冶炼影响的基础上,根据新余锰铁高炉生产实践,对脱湿鼓风节焦增产效果进行了分析计算。结果表明:按3座255m~3锰铁高炉在二、三季度(脱湿期)脱湿10.19g/m~3计算,全年节焦、增产、提高锰铁质量所获得的经济效益约为1500万元,效果十分显著。脱湿鼓风是该厂锰铁高炉技术进步发展方向之一。     

焦炭质量的供需差距及提高焦炭质量的途径

分析了高炉大型化和富氧喷煤技术对焦炭质量的及现有焦质量的差距,将焦冷态强度和热态强度辩证统一起来研究其在高炉冶炼中的工作特性。从焦炭生产的各个环节出发,探讨了提高焦质量的途径。     

特大型高炉先进技术应用及实践

介绍了山东钢铁特大型高炉所采取的先进技术,包括:紧凑型铁钢界面技术、高炉组联合矿焦槽技术、高炉长寿综合技术、新型自然风冷主沟技术、特大型顶燃式热风炉技术、高炉煤气全干法布袋除尘技术及煤气输灰技术、炉顶均压煤气回收技术等。同时对1#、2#高炉生产实践进行简要说明。     

八钢5号高炉使用冶金三级焦冶炼生产实践

通过八钢5号高炉使用冶金三级焦冶炼,对高炉操作制度及关键操作参数的选择,以及近三个月生产实践,指出八钢5号无料钟高炉在大量使用冶金三级焦的条件下,采用适当的装料制度,合适的炉温、炉渣碱度控制,强化炉外管理,高炉也能达到改善技术经济指标,长期稳定和顺行,降低吨铁成本的目的。     

Neurogenic inflammation in the gastrointestinal tract of the rat

To estimate the risk of repeat low birthweight deliveries among women whose first child was very low birthweight (less than 1500 g), a retrospective cohort of women who had their first and second children in Washington state between 1984 and 1991 was studied. After adjustment for potential confounding factors, a woman whose first infant was very low birthweight experienced an 11.5-fold increased risk of delivering a low birthweight (less than 2500 g) second infant (relative risk 11.5, 95% confidence interval 5.4 to 24.4). Women with a very low birthweight first infant also had a significantly increased risk of repeat very low birthweight infant (p < 0.0001). Women with a previous very low birthweight delivery are at increased risk of repeat low and very low birthweight infants. This high-risk group may benefit from education regarding recurrence risk and modification of factors associated with low birthweight, as well as good prenatal care.     

Q175低碳低硅冷加工用拉丝线材的试制开发

介绍了低碳低硅冷加工用拉丝线材的化学成分、生产工艺设计及新产品开发。试制结果表明:Q175冷加工用拉丝线材化学成分设计合理,以铁水预脱硫—100 t顶底复合吹炼转炉冶炼—底吹氩、喂线—方坯连铸(150 mm×150 mm)—高速线材控轧控冷生产的Q175冷加工用拉丝线材,其产品质量、性能完全满足文具等五金制品企业的拉丝、冷加工等要求。     

Restraining the Golem: Boosting performance by changing the interpretation of low scores.

The Golem effect is the negative impact on subordinates' performance that results from low leader expectations toward them. The effects of low expectations were studied experimentally by preventing the natural formation of low expectations toward individuals who had obtained low test scores in some units and by refraining from doing so in other units. Randomly selected squad leaders (n?=?17) were led to believe that low scores on a physical fitness test were not indicative of subordinates' ineptitude. Control squad leaders (n?=?17) were not told how to interpret the test scores. Two posttests showed that low-scoring personnel in the experimental squads improved more than those in the control squads, maintained the difference, rated their squad leaders more favorably, and were more satisfied, but they were not significantly more anxious. The potential for low scores on valid tests to produce unintended Golem effects is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Community studies of the health service implications of low back pain

STUDY DESIGN: Retrospective study using primary care physician case notes and a self-report questionnaire on the same randomly selected population sample. OBJECTIVES: To assess the prevalence, management, and outcomes of low back pain in the community, comparing, in the same random sample of registered patients, self-report questionnaire data and primary care physicians' records. SUMMARY OF BACKGROUND DATA: The financial and resource implications of low back pain are extensive. Data on consultations, investigations, and the management of low back pain are fragmentary and there are no comparisons estimating prevalence from case notes and self-report. METHODS: A retrospective study of prevalence, management, referral, and outcome covering the previous 12 months was carried out in three general practices using case notes and a self-report postal questionnaire on a sample of 900 patients over 18 years. RESULTS: Lifetime prevalence of low back pain was 62%. Annual prevalence was 48%, with 16% reporting low back pain at the time of report. Twenty-four percent consulted their primary care physician for low back pain, of whom 17% were referred to a hospital specialist. The annual consultation rate of patients with low back pain was similar to the rate for patients with chronic conditions. The activities of daily living were restricted in less than half, with few taking sick leave. The general health status of those reporting recent low back pain was significantly lower than those not reporting low back pain. Most felt that low back pain was self-limiting and would not consult health professionals for future episodes. There were substantial discrepancies between case notes recorded at consultation with the primary care physician and self-report regarding consultation and investigations. CONCLUSIONS: Prevalence rates were comparable with those reported in other studies. The significant discrepancies between data sources suggest patient recall bias or underrecording in case notes. The low consultation rate, time off, and day-to-day disability indicate that most episodes are self-limiting.     

Effect of RE Elements on the Morphology of Carbides and the Impact Fatigue Properties of the Low Cr White Cast Iron

An apparatus of zone melting unidirectional solidification with a steep temperature gradient andan impact fatigue tester were used.The effect of RE elements on the morphology of carbides and the impactfatigue properties of the low Cr white cast iron were investigated.Experimental results showed that the modi-fying effect of RE elements was remarkable on the M3C carbides.With the addition of RE elements in thelow Cr iron,a lot of plate-like carbides were transformed into lath-like and rod-like ones.The higher thecontent of RE elements was,the more was the fraction of the lath-like and rod-like carbides.In the low Crwhite cast iron,the RE modifying agent can efficiently increase the impact fatigue resistance and decrease thecrack growth rate and delay the time of incipient cracking.With the increase of the content of RE elements inthe low Cr cast iron,the impact fatigue resistance increased greatly and the crack growth rate decreased rap-idly.     

Differential developmental fates of the two calcium currents in early embryos of the ascidian Ciona intestinalis

Two voltage-dependent calcium currents have been described in unfertilized eggs of the ascidian Ciona intestinalis: a low threshold, slowly activating current, and a high threshold fast one. According to the classical criteria for classification of calcium currents, they both share some of the features of L-like and T-like currents. We have studied these two calcium currents further by measuring their sensitivity to permeant ions, temperature and inhibitors. Both currents were sensitive to relatively high concentrations of nitrendipine, which was a selective blocker of the low threshold channel. The lanthanide ion gadolinium was a potent blocker of the low threshold current, and cadmium preferentially inhibited the high threshold current. The two calcium currents were regulated in a different manner after fertilization. The density of the high threshold current remained relatively constant, while the low threshold current was lost by the time of first cleavage. This loss following fertilization is similar to the loss of a low threshold sodium current in fertilized eggs of the ascidian Boltenia villosa. Block of the cell cycle with various compounds did not prevent loss of the low threshold calcium current. This observation adds weight to the hypothesis that a loss of excitability is a general property of early development. We conclude that fertilization can differentially modulate channel populations before first cleavage. The mechanism by which this occurs in the ascidian embryo has yet to be discovered.     

Influence of sex roles on the manifestation of leadership.

Investigated situational factors influencing the manifestation of dominance (Do) by pairing 80 undergraduates high and low on the CPI Do scale and having them interact in tasks in which 1 had to lead and the other follow. In experiments using a masculine industrial task and a sexually neutral clerical task, the following S pairs were studied: high and low Do men (Group 1), high Do men and low Do women (Group 2), high Do women and low Do men (Group 3), high and low Do women (Group 4). Assumption of leadership by the high Do women in Group 3 was significantly lower in both studies. This was attributed to sex role conflict inhibiting the manifestation of Do. Analyses of the decision-making process support this interpretation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of the synchronization of the degradation of dietary crude protein and organic matter and feeding frequency on ruminal fermentation and flow of digesta in the abomasum of dairy cows

Four Holstein cows in midlactation were equipped with ruminal and abomasal cannulas and used to study the effect of synchronized degradation of crude protein (CP) and organic matter (OM) and feeding frequency on digestion and outflow of nutrients. A 4 x 4 Latin square design was used. Diets were arranged in a 2 x 2 factorial design; the four diets contained high ruminally degradable OM and high ruminally degradable CP, high ruminally degradable OM and low ruminally degradable CP, low ruminally degradable OM and high ruminally degradable CP, and low ruminally degradable OM and low ruminally degradable CP. In each period, cows were fed four times daily from d 1 to 14 and two times daily from d 15 to 28. Mean daily ruminal ammonia N concentration was reduced by high ruminally degradable OM, low ruminally degradable CP, and twice daily feeding. Fluctuation in ruminal ammonia N was lower when cows were fed four times daily than when cows were fed twice daily. Plasma urea N concentrations were lower for cows fed diets that were high in ruminally degradable CP. Higher CP flow in the abomasum was found for cows fed the diet containing high ruminally degradable OM and low ruminally degradable CP. Microbial dry matter and CP flow to the abomasum were higher for cows fed twice daily than for cows fed four times daily. Flow of OM in the abomasum was not altered by concentrations of ruminally degradable OM or CP. These results suggest that the available energy in the rumen (ruminally degradable OM) is the most limiting factor for ruminal N utilization under our experimental conditions. Use of these data may improve the prediction of plasma urea N.     

Troglitazone increases the resistance of low density lipoprotein to oxidation in healthy volunteers

The oxidative modification of low density lipoprotein is of importance in atherogenesis. Antioxidant supplementation has been shown, in published work, to increase low density lipoprotein resistance to oxidation in both healthy subjects and diabetic subjects; in animal studies a contemporary reduction in atherogenesis has been demonstrated. Troglitazone is a novel oral antidiabetic drug which has similarities in structure with vitamin E. The present study assessed the effect of troglitazone 400 mg twice daily for 2 weeks on the resistance of low density lipoprotein to oxidation in healthy male subjects. Ten subjects received troglitazone and ten received placebo in a randomised, placebo-controlled, parallel-group design. The lag phase (a measure of the resistance of low density lipoprotein to oxidation) was determined by measurement of fluorescence development during copper-catalysed oxidative modification of low density lipoprotein. The lag phase was increased by 27 % (p < 0.001) at week 1 and by 24% (p < 0.001) at week 2 in the troglitazone treated group compared with the placebo group. A number of variables known to influence the resistance of low density lipoprotein to oxidation were measured. They included macronutrient consumption, plasma and lipoprotein lipid profile, alpha-tocopherol, beta-carotene levels in low density lipoprotein, low density lipoprotein particle size, mono and polyunsaturated fatty acid content of low density lipoprotein and pre-formed low density lipoprotein hydroperoxide levels in low density lipoprotein. Troglitazone was associated with a significant reduction in the amount of pre-formed low density lipoprotein lipid hydroperoxides. At weeks 1 and 2, the low density lipoprotein hydroperoxide content was 17% (p < 0.05) and 18% (p < 0.05) lower in the troglitazone group compared to placebo, respectively. In summary the increase in lag phase duration in the troglitazone group appeared to be due to the compound's activity as an antioxidant and to its ability to reduce the amount of preformed low density lipoprotein lipid hydroperoxides. This antioxidant activity could provide considerable benefit to diabetic patients where atherosclerosis accounts for the majority of total mortality.