高频燃烧红外吸收法测定氮化硅铁中碳

称取0.2g样品,置于预先盛有(0.300±0.005)g锡粒的坩埚内,覆盖(0.400±0.005)g纯铁和(2.000±0.005)g钨粒进行分析,建立了高频燃烧红外吸收法测定氮化硅铁中碳含量的分析方法。实验中,考虑到氮化硅铁标准样品较少,故选择由0.04g氮化硅标准样品JCRM R008和0.16g纯铁标准样品GBW 01148a混合配制的氮化硅铁合成校准试样(w(C)=0.025 7%)与氮化硅铁标准样品GSB 03-2469-2008(w(C)=0.35%)来绘制校准曲线。方法中碳的线性范围为0.025%~0.35%,检出限为0.000 45%。由0.10g氮化硅标准样品JCRM R008和0.10g纯铁标准样品GBW 01148a混合配制氮化硅铁合成样品1,以及由0.08g氮化硅铁标准样品GSB 03-2469-2008和0.12g氮化硅标准样品JCRM R006混合配制氮化硅铁合成样品2,采用实验方法对其中碳进行测定,测定值与认定值基本一致。采用实验方法对氮化硅铁实际样品中的碳进行测定,所得结果的相对标准偏差(RSD,n=6)为1.2%~1.7%。     

硅铁冶炼反应机理探讨

一、概述要深入了解硅铁炉内的主要物理化学过程,认清炉内不同区带分别进行哪些反应,从而创造这些反应进行的条件,充分利用炉内各区带的物质和热量,必须进一步研究冶炼时从炉料变化到液体硅铁形成全过程的模     

氮化硅铁对无水炮泥性能影响的研究

根据无水炮泥的基本配合比,分别用不同比例的氮化硅铁替代其中的刚玉作基质料,在埋炭条件下经110℃×24 h,900℃×2 h处理,以及在通氮气条件下经1500℃×2 h煅烧后,分别检测和分析了试样的物理性能。结果显示,试样的烘干强度最大,中温强度最低,高温强度介于两者之间。随着氮化硅铁含量从4%递增到12%,试样经过1500℃高温处理后,其常温耐压强度和抗折强度均呈递增趋势,当氮化硅铁含量为10%时达到最大值,体积密度则呈下降趋势,同时试样的抗渣渗透性能和抗渣侵蚀性能得到了提高,试样的钻孔开口时间逐渐缩短。     

氮化硅铁及其在耐火材料中的应用

氮化硅铁是近年来高温材料领域的新型复相材料,主要由氮化硅和硅铁合金组成。自20世纪70年代以来,氮化硅铁作为高炉用炮泥材料取得了良好的使用效果,但其制备成本过高制约了进一步的发展。20世纪90年代,北京科技大学无机非金属结构材料研究室利用闪速燃烧合成技术实现了氮化硅铁高性价比的大规模产业化制备,大大推动了氮化硅铁材料的研究与应用,在铁钩浇注料等领域取得了良好的使用效果。本文介绍了氮化硅铁的制备、结构及性能,分析了闪速燃烧合成氮化硅铁的工艺原理,总结了氮化硅铁在不同应用环境下的使用性能,以及目前的应用状况,并展望了氮化硅铁材料的研究方向及其潜在的应用领域。     

高氯酸脱水重量法测定氮化硅铁中硅含量

采用高氯酸脱水重量法测定氮化硅铁中的硅含量。将氮化硅铁试样用过氧化钠-碳酸钠混合熔剂熔解,经盐酸酸化,加高氯酸冒烟,硅酸脱水,沉淀于950℃马弗炉灼烧至恒重;加入硫酸、氢氟酸处理,使硅转化成四氟化硅逸出,再灼烧至恒重,根据酸处理前后两次的质量差计算硅的质量分数。实验结果表明,该测定方法简单易行,可使试样溶解完全,测定精密度和准确度都很高,能够满足使用要求。     

FeSi75铁合金显微结构与氮化性能的研究

利用XRD、SEM和EDS等手段对氮化硅铁合成原料FeSi75的物相及显微结构进行了分析。结果表明，合金中的主要物相单质硅以网状结构存在，铁元素只存在于ξ相熔体及少量的FeSi2中，且镶嵌于硅结晶的网状结构中。破碎后ξ相颗粒尺寸较小，分布均匀，这种结构和特性有利于FeSi75氮化反应的进行，并用热力学进行了证明，从而为FeSi75成为氮化硅铁的合成原料提供了理论依据。     

竖式中频炉加工氮化钒VN16技术研究

研究了利用竖式中频炉加工氮化钒VN16产品的技术。通过对氮化钒合成过程中的反应机理、反应条件等试验分析,结合工业化试验,实现了利用竖式中频炉将VN12以低成本加工成VN16产品,使氮化钒产品达到了增值的目标。     

氮化硅铁中氮的测定方法

在硅钢研制、冶炼时,需分析氮化硅铁中的总氮量。目前钢铁中氮的分析方法,一般采用酸法。但用酸法测定氮化硅铁中的总氮量,试样分解不完全,不能定量地测定氮的总量。为解决这个问题,我们参照上海硅酸盐研究所的"氮化硅中氮和硅的测定方法"一文(发表干"分析化学"1973年第1期),进行了一系列的条件试验     

多膛炉钼焙烧常见料脊现象的探究

钼精矿在多膛炉氧化焙烧过程中物料会发生料脊现象，粘附在耙臂和耙齿上，严重时造成死炉，影响正常生产。结合理论基础和现场生产工艺对多膛炉焙烧时炉内料脊的分层现象做了分析，总结出焙烧过程中炉内产生的料脊形状，并分析探讨各种料脊产生的原因，最终提出防止料脊形成的措施和方法。     

高炉炮泥中氮化物的组成与结构分析

为了改善高炉炮泥的烧结性能,提高其抗侵蚀能力,在炮泥配料中加入了氮化硅或氮化硅铁。对加人氮化物的炮泥组成与结构以及氮化物的作用机理进行了分析。结果表明：氮化硅存在由氮氧化物转化为氧化物的反应过程,而氮化硅铁则氧化为硅铁的氧化物。氮化物的氧化过程伴随着结构致密化反应,能减缓碳的氧化,从而改善炮泥的耐用性能。     

The structure of intraindividual value change.

Values are assumed to be relatively stable during adulthood. Yet, little research has examined value stability and change, and there are no studies on the structure of value change. On the basis of S. H. Schwartz’s (1992) value theory, the authors propose that the structure of intraindividual value change mirrors the circumplexlike structure of values so that conflicting values change in opposite directions and compatible values change in the same direction. Four longitudinal studies, varying in life contexts, time gaps, populations, countries, languages, and value measures, supported the proposed structure of intraindividual value change. An increase in the importance of any one value is accompanied by slight increases in the importance of compatible values and by decreases in the importance of conflicting values. Thus, intraindividual changes in values are not chaotic, but occur in a way that maintains Schwartz’s value structure. Furthermore, the greater the extent of life-changing events, the greater the value change found, whereas age was only a marginal negative predictor of value change when life events were taken into account. Implications for the structure of personality change are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Personality change as a result of an experimental change of environmental conditions.

To what extent can personality change, when it occurs, be understood in terms of effect of specific environmental conditions? In a large clerical organization, two experimental groups were created and subjected for more than a year to different programs of control. A paper-and-pencil questionnaire designed specifically to measure 26 personality trends to which each of the programs had some degree of relevance was administered near the beginning of the experimental period and about a year later at the end." The two programs "were seen to have profound effects on the subjects' attitudes toward the company and satisfactions in it." A table of before-after correlations and incidence of change is presented. "Twelve changes in the predicted direction prove significant at the .05 level of confidence. Six changes significant at the .05 level occur in a direction opposite to that predicted… . Although somewhat ambiguous, the data seem to indicate that measurable change can be effected by a persisting change in environmental conditions." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extent of opinion change as a function of amount of change advocated.

"Three different degrees of change in opinion were advocated by communications presented in such a way as to be independent of the recipient's own position." Communications advocating most extreme change had the greatest influence, those advocating moderate change had the next greatest influence, and those advocating the smallest change had the least influence. At the same time the ratio of change produced to that advocated declined, average amounts of change being 58%, 62%, and 88%, respectively, of the amount of change advocated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prévention, détection et traitement de l'information persuasive en situation de peur.

Evidence from psychological research has shown the importance of fear on attitude and/or behaviour change. Study 1 showed that fear appeal messages that produce high levels of fear are more effective with health prevention responses than with detection responses, and that this effect is reverse with messages that produce low levels of fear. Study 2 showed that for high fear arousal, interventions such as objective processing (vs. imagery processing) enhance persuasion by reducing the need to avoid the message. Low fear arousal increases persuasion for detection responses. Interventions such as objective processing (vs. imagery processing) interferes with persuasion by reducing persuasion. These variables must be taken into account if one wants to set up an effective fear-persuasive communication campaign. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of uncertainty in cognitive change.

Cognitive change was hypothesized to be related to level of S's feeling of uncertainty. Judgments of a photographic stimulus under varying conditions of feedback and quality of stimulus were elicited. The results indicated that change in judgment (cognitive change) is associated with change in level of uncertainty, and the conditions of cognitive change were similar to the Lewinian conceptualization of social change. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Review of Psychotherapeutic change: An alternative approach to meaning and measurement.

Reviews the book, Psychotherapeutic change: An alternative approach to meaning and measurement by Alvin R. Mahrer (1985). This small and unpretentious volume is a welcome addition to the growing number of recent publications in the field of psychotherapy research that emphasize the need for innovative and more dynamic and functional conceptualizations of the meaning and measurement of psychotherapeutic change. Despite (or perhaps because of) its provocative content, Psychotherapeutic Change is an enjoyable book to read. Mahrer's style of writing is engaging, clear, and free of the customary clinical jargon. Also refreshing is the fact that the material throughout the book comes straight from the concerns of a practitioner. Although the reader may not always agree with the author and may be annoyed by the occasional repetitiveness of some ideas, this book will prove to be a source of stimulating ideas for students, clinicians, and researchers of psychotherapy alike. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual marking and visual change.

Five experiments investigated the types of changes that disrupt the preview effect--the benefit gained in difficult search tasks from presenting some distractors earlier in time. A shape change with or without an overall luminance change at the location of an old item was found to disrupt the preview effect, whereas an equivalent luminance change alone or an isoluminant color change was not disruptive. Results suggest that (a) relatively low-level visual changes may not be sufficient to abolish the benefit, (b) the benefit most likely occurs through inhibition applied to locations within a location master map, and (c) inhibition need not be applied to surface features of objects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

When change in the self is mistaken for change in the world.

The authors examined whether and when changes in the self lead to mistaken assessments that the world has changed. Survey data revealed that: personal changes in respondents (e.g., parenthood, financial change) were positively correlated with their assessments of various social changes (e.g., crime rates, freedom). Experimental data provided converging evidence. Experimentally induced change in knowledge influenced participants' perceptions of change in an author's writing style from one decade to the next (Study 3). Bringing self-change to participants' attention attenuated their judgments of change in the world when they had sufficient cognitive resources to consider how such self-changes might affect their perceptions (Studies 4-6). Discussion highlights how such misattributions of change contribute to the pervasive belief in societal decline. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Engagement et persuasion par la peur: Vers une communication engageante dans le domaine de la santé.

Evidence from psychological research has shown the importance of fear on attitude and/or behavior change. The experiment hereby quoted tests the influence of commitment (high vs. low) on an attempt of persuasive message for a forthcoming effect, that is, after reading an antialcohol message to subjects. The idea consists in inducing alcohol consumers toward modifying their attitude and behavioral intentions toward alcohol. As expected, the high committed drinkers (i.e., regular drinkers) resist persuasion (on the level of both attitude and intention). The low committed drinkers (i.e., occasional drinkers) do not resist persuasion but adopt further on a more favorable attitude toward alcohol. The drinkers who had read a strongly threatening, yet at the same time strongly reassuring, message express the strongest intention to reduce their alcohol consumption. Results are described with reference to Witte's (1998) extended parallel process model. A new perspective is presented at the end of our paper, that is, toward a "committing communication." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

3000t热矫直机辊系更换的优化与改造

分析辊系更换现状,查找影响辊系更换效率的因素,通过系统地优化辊系更换方案,提升辊系更换效率,大幅缩短了换辊时间。