连轧管机轧辊轴承的调整、维护及保养

本文介绍了应用于MPM连轧机轧辊上的四列圆锥滚子轴承的结构特性及其调整、维护、保养，旨在提高轴承的使用寿命。     

钢纤维含量对汽车摩擦材料性能的影响

通过调整摩擦材料基础配方中钢纤维的含量,采用直接混合工艺制备不同组分的摩擦材料,对其进行理化性能、力学性能、摩擦性能及制动噪音测试。结果表明:随钢纤维含量增加,摩擦材料的密度、p H值和洛氏硬度均增大,常温压缩量减小;气孔率先减小,当钢纤维含量超过21%后,气孔率增大;名义摩擦因数(μnom)先略微降低后升高,最低摩擦因数(μmin)、磨损量和噪音发生率均增加,但当钢纤维含量超过21%后,磨损量和噪音发生率明显增加。     

Recalled dream content and the maintenance of body image.

Focused on the amount of physical activity in the recalled dreams of 27 paralyzed and 29 normal men. 1 hypothesis, derived from Rorschach's work, was that dreams are kinesthetic phenomena which continuously function to maintain body image. A 2nd, alternative hypothesis was that dreams serve an emergency repair function, buttressing body image only when the latter is in flux. While no general upsurge of kinesthetic dream content was found in the paralyzed-S group, recently paralyzed men were found to have more, and long-term paralyzed men less, kinesthetic dream content than did normal men. Results support the emergency repair theory of dream function. The necessity for a 2-factor theory of dream function is considered. (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

宝钢150 t电炉出钢口维护操作实践

论述了电炉出钢口维护的一般模式,通过宝山钢铁股份有限公司150 t电炉出钢口维护模式的改进,减少了整体更换的次数,提高了出钢口内衬整体使用寿命,稳定了生产节奏,而且施工方法简单,便于操作和推广.     

Correlation of BOS process variables with dust mass formation and zinc content

Abstract

The basic oxygen steelmaking (BOS) process typically produces a dust rich in valuable iron units and often contaminated with zinc. This paper takes a look at statistical correlation and multiple regressions of process variables with the quantity of dust and the zinc mass contained in the dust. A robust inline sampling system was designed and installed to isokinetically sample the primary BOS dust slurry from a 248 m³ capacity BOS converter at Tata Steelworks Port Talbot (UK). This system was used to measure the dust mass and composition changes against time for 12 large scale trial heats and to compare with the process information data for a statistical evaluation of the variables. Statistically significant Pearson linear correlations were measured for the total dust mass produced with the iron ore and for the zinc mass contained in the dust with the addition of waste oxide briquettes (WOBs). A multiple regression analysis model showed strong associated correlations between the zinc mass contained in the dust with the galvanised scrap and WOB additions and explained 73% of the zinc mass variance.     

武钢自备车转8A转向架检修的探讨

对武钢自备车转8A转向架检修工装、工艺及现状进行分析探讨,寻找适合武钢运行条件及现状的转向架检修方法。     

烧结机头电除尘器运行和维护

根据烧结机头的工艺状况和烟尘的特点 ,详细介绍了国内烧结机头电除尘器的运行情况及存在的问题。提出了保证机头电除尘器稳定、可靠、高效运行的维护措施 ,为烧结机头电除尘器的技术改进提供了参考和借鉴。     

铜含量对铁基粉末冶金航空刹车材料摩擦磨损性能的影响

讨论了大范围内铜含量(0～30％,质量分数)对铁基粉末冶金航空刹车材料摩擦磨损性能的影响和材料的摩擦磨损机理,结果表明:不合铜时,材料的摩擦因数和磨损量均较大,磨损机理主要为粘着磨损;添加铜后,材料的摩擦因数和磨损量均有所下降,疲劳磨损为主要机理;当铜含量升高到有大量游离铜存在时,材料的摩擦因数和磨损量逐渐增加,磨损机理又主要体现为粘着磨损。     

Better discrimination of small changes in commonly encountered than in less commonly encountered auditory stimuli.

Results from 3 auditory tasks revealed that small changes made in stimuli commonly encountered in everyday life are more easily discriminated than are the same changes made in stimuli not as commonly encountered. The tasks required discrimination of a frequency difference in 1 tone of 6-tone chords or nonchords, discrimination of a duration difference in 1 note of common tunes or nontunes, and discrimination of the deletion of a band of frequencies from speech sounds played forward or backward. Different crews of college-aged listeners served in the different tasks. If future research shows this difference in discriminability to be a general property of commonly encountered stimuli-attributable to a difference in the way they are processed in the nervous system—then discrimination tests of this sort could become useful for assessing whether stimuli have made the transition from one form of processing to the other. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

含铁量高的电弧炉烟尘固体废物综合表征

进行含铁量高的电弧炉烟尘物料的固体废物鉴别时,首先应利用X射线荧光光谱(XRF)确认物料的主要成分及其质量分数、X射线衍射仪(XRD)和矿相显微镜分析物料的主要物相组成等基本理化性质指标;当物料的基本理化性质指标与含铁量高的电弧炉烟尘相同时,再利用矿相显微镜、扫描电子显微镜和激光粒度分析仪分析物料的特征性理化性质指标,包括金属铁和铁氧化物的存在形态、微粒的微观形态和粒度分布,如果至少有一个特征性指标与含铁量高的电弧炉烟尘相同,即可确定物料的产生来源为含铁量高的电弧炉烟尘;最后,根据《固体废物鉴别标准 通则》(GB 34330—2017)得出物料的固体废物鉴别结论。试验研究指出了含铁量高的电弧炉烟尘物料的三大特征性理化性质指标和固体废物鉴别流程,为含铁量高的电弧炉烟尘物料的固体废物鉴别和监管提供参考,对将其堵在国门之外具有重要意义。     

Allergen content in dust from homes and schools in northern Norway in relation to sensitization and allergy symptoms in schoolchildren

BACKGROUND: Previous studies have shown a high prevalence of atopic diseases among school children in the community of S?r-Varanger. Moreover, animal dander followed by pollen and house dust mite, were the most common allergens in skin prick tests. OBJECTIVE: To assess the allergen content in homes (living-rooms and mattresses) and classrooms of children living in an arctic area at 70 degrees. The presence of allergens in homes and schools and their relationship to atopy was of particular interest. METHODS: Dust samples from 38 homes and seven schools in northern Norway were collected by vacuum cleaning. The presence of allergens of dog, birch, timothy, Cladosporium herbarum, codfish and hen egg-white was investigated by radio-allergosorbent test (RAST) inhibition and the presence of major allergens of cat Felis domesticus (Fel d I) and house dust mites (HDM) Dermatophagoides pteronyssinus (Der p I) and Dermatophagoides farinae (Der f I) by enzyme-linked immunosorbent assay (ELISA). RESULTS: Mattresses contained significantly more dust per unit area than living-rooms and classrooms. No statistically significant differences in allergen content for dog, birch, timothy. Cladosporium, codfish and hen egg-white were seen between HDM-sensitized and non-atopic children. Most dust samples contained dog allergens with the highest allergenic activity found in living-rooms of those keeping dogs. An increased level of Fel d I was detected in only one of 38 samples from living-rooms (this family kept a cat) and in 25 of 38 samples from mattresses with ranges from 24 to 84 ng/m2. The highest concentrations were found in mattresses of children keeping cats. Increased levels (> or = 25 ng/m2) of Der p I were found only in homes and virtually only in mattresses of HDM-sensitized children. An increased level of Der f I was found in only one case, i.e. in the mattress of an HDM-sensitized child where additionally Der p I and HDMs were demonstrated microscopically. When relating Der p I to HDM-sensitization an odds ratio of more than 16 (95% CI: 1.6-394.3) was found. All extracts from living-rooms included codfish allergens. Low RAST inhibition values were detected for hen egg-white. Cladosporium, birch and timothy pollen in most samples. Furthermore, the study demonstrated that dust from schools was relatively free of allergens. CONCLUSION: Previous findings indicating that the main allergen exposure problem in this geographical area is that of pet allergens were confirmed.     

制动条件对粉末冶金航空刹车副钢对偶金相组织的影响

欧美飞机常使用的粉末冶金航空刹车副选用粉末冶金刹车材料和钢对偶材料配对作为摩擦偶以达到制动目的,而其钢对偶材料组织在使用过程中的变化一方面反映了航空刹车副所经历的刹车过程累计状况,另一方面也将影响刹车副的正常制动性能.作者研究了不同制动条件如正常着陆刹车、中止起飞、极限磨损状态中止起飞等3种条件下,粉末冶金航空刹车副钢对偶材料30CrSiMoVA的组织变化情况,并初步比较了不同组织状况下刹车副的摩擦磨损性能.研究结果表明,在3种条件下,表面均形成了塑性变形区.在正常着陆条件下,内部组织由回火索氏体转变为板条状马氏体;而在中止起飞和极限磨损状态中止起飞条件下,钢对偶材料组织则发生更为显著的变化.体现在恢复性试验中,刹车压力需求明显增大.     

Complex Processing of Wastes Generated in Chrysotile Asbestos Production

A new recycling technology has been studied in this work to produce magnesium chloride from wastes generated in chrysotile asbestos production. The steps include enrichment of raw material by sizing, leaching of magnesium with hydrochloric acid, purification of solution from impurities of iron and nonferrous metals, and the production of magnesium chloride solutions. Thermodynamic analysis shows the possibility of dissolution of magnesium compounds in the waste by hydrochloric acid. Magnesium chloride solution is subjected to hydrolytic purification from iron and nickel. Enrichment has been carried out with material particle size of 0.25 mm and liquid to solid ratio of 4:1 and leaching with 25% concentrated hydrochloric acid has been accomplished with a stoichiometric flow rate. Hydrolytic treatment was carried out at a pH 7.5–8.0. pH adjustment was carried out by magnesium oxide. Extraction of 92% of magnesium from serpentinite was achieved.     

Epithelial repair in asthma. Do the benefits of house dust mite avoidance result from proteinase avoidance?

OBJECTIVE: To describe the timing of recovery of lung function after severe acute hypoxemic respiratory failure (AHRF) in children. DESIGN: A serial observational follow-up study of clinical and lung function measurements up to 53 months after acute illness. SETTING: University pediatric intensive care unit in a national children's hospital. PATIENTS: Five critically ill children aged 5-14 years. INTERVENTIONS: None RESULTS: Clinical recovery: each patient required a 3-5 month convalescence before being able to attend full-time school because of lethargy and dyspnea. All patients developed wheeze 3-12 months after illness and four received long-term bronchodilator therapy. Lung function recovery: for both the forced vital capacity (FVC) and forced vital capacity in the first second (FEV1) four patients had abnormally low values, regaining only 60-70% of predicted values for their height and sex, and all of this improvement had occurred by 6-12 months after illness. Beyond this interval, patients remained on their same FVC and FEV1 centile. FEV1/FVC ratios were consistently within the normal range, indicating a predominantly restrictive defect. Changes in peak expiratory flow exhibited a time course of improvement similar to the other lung function tests. CONCLUSION: In children, pulmonary recovery after severe AHRF may occur for 6-12 months. A 1-year follow-up could offer a rational single point for assessment of outcome and long-term counselling of child and parents.