X100管线钢断口分层机理分析

根据X100管线钢断口分层现象,对该钢圆棒形及板形拉伸试样断口及不同温度下冲击试样断口进行宏观观察、显微分析、金相观察和EBSD织构分析。结果表明,随拉伸试样形状及尺寸的变化,裂纹分层现象趋势不同,随冲击试验温度降低,裂纹趋势加剧,裂纹的萌生以及扩展受晶界的限制。EBSD织构分析表明,沿{113}〈110〉方向,在一定微区存在较强的织构,促进了断口分层的产生。     

试样缺口形状及加工精度对冲击功的影响

用示波冲击试验技术对V型、U型两种缺口试样的示波曲线进行了分析。结果表明,试样缺口形状尺寸及加工精度,对裂纹形成功有很大影响,是改变冲击功的根本原因。而裂纹扩展功由试验温度和材质因素决定,不受缺口形状尺寸及加工精度的约束。示波冲击试验可以比较直观地反映材料的断裂过程。     

打击速度对冲击性能的影响

用德国生产的PW15／30示波冲击试验机对小尺寸辅助试样作了一系列不同温度／不同速度的试验，研究了不同的打击速度（即冲击能量）对冲击吸收功Ak值的影响及其对裂纹形成功A1和裂纹扩展功Ap的影响。     

应用示波冲击法研究Q960钢焊接热模拟冲击韧性

利用示波冲击方法对Q960钢的焊接热模拟冲击韧性展开研究。对不同热输入下峰值温度分别为1 300℃、1 100℃和850℃的焊接热模拟试样进行了示波冲击和组织检验。结果表明:峰值温度为1 300℃时,热模拟试样的组织以马氏体为主,峰值温度为1 100℃和850℃时,热模拟试样的组织以贝氏体为主;峰值温度为1 300℃时,热模拟试样的裂纹扩展功Wp随焊接热输入的增加先升高后降低,峰值温度为1 100℃和850℃时,热模拟试样的裂纹扩展功Wp随焊接热输入的增加呈现降低的趋势。     

X70管线钢的断裂韧性

对不同厚度和裂纹初始长度的X70管线钢三点弯曲试样进行了不同试验温度下的断裂韧性试验。试验和分析结果表明：随着试验温度降低，试样的破坏方式由韧性破坏向脆性破坏转换不同厚度试样的破坏断口均产生分层裂纹，分层裂纹的大小和数量与试样厚度有关，分层裂纹的位置与试验温度和裂纹初始长度有关；对于试验温度较低的脆性断裂，试样在破坏时产生的分层裂纹距主裂纹根部有一定距离，分层裂纹宽度较小且未充分张开，对厚度效应影响较小。对于试验温度较高时的韧性断裂，分层裂纹首先出现在主裂纹根部，试样破坏时分层裂纹宽度较大且充分张开，减小了试样的有效厚度。高强度、高韧性的X70管线钢由于分层裂纹的产生，其力学性能与具有普通强度和韧性的钢材的力学性能存在着明显的差异，普通金属材料的韧性试验方法和材料评价方法已不再适用，必须考虑管道壁厚、缺陷大小和环境温度的综合作用。     

示波冲击试验技术的研究

介绍了示波冲击试验技术及其用于评价材料的动态断裂韧性方面的试验研究结果。采用了对变形速率不敏感的铝合金试样的静弯曲曲线与动态的示波冲击曲线的对比,较准确地标定了示波冲击曲线图中的载荷坐标,并且对14MnMONbB,12CrNi3MoV和12CrNi5MoV等三个低合金高强度钢进行了系统的示波冲击试验,研究不同缺口形状的冲击试样、试验温度对示波图形的影响。结果表明:用预裂纹试样能够比较直观地反映材料的断裂韧性;随着试验温度的降低其裂纹扩展功不断下降。     

Q345E钢棒材低温冲击功的研究

研究了单独铝微合金化Q345E钢Φ20mm棒材普通轧制工艺和控制控冷轧制工艺在不同温度下的冲击功、强度变化,并对试样的晶粒度和金相组织进行了分析。采用控轧控冷的轧制生产工艺,可使Q345E棒材轧态的晶粒度细化至9.5级,-40℃冲击功达到120J以上,达到了标准的要求,降低了生产成本,提高了钢材的市场竞争力。     

影响S460M钢板韧性的因素分析

根据韶钢生产S460M钢板的冲击功分布情况,分析了典型冲击功不合格试样的断口形貌及微观组织。结果表明:由于成分设计及生产工艺制定不合理,导致钢板中心偏析严重,厚度方向晶粒差异较大,越往中心晶粒越粗大。晶粒粗大且分布不均匀致使晶间结合力减弱,裂纹扩展阻力变小,最终导致钢板韧性变差。     

轧制工艺对气瓶钢板示波冲击性能的影响

应用示波冲击试验测量了不同终轧温度下HP295钢板在系列温度下的冲击韧性，测量了冲击断口试样的横向扩张量，利用扫描电镜分析了示波冲击断口形貌，结果表明，终轧温度提高，钢的韧脆转变温度提高，钢的冲击韧性下降，裂纹扩展功下降，示波冲击温度越低，终轧温度对韧性的影响越显著，冲击韧性与冲击断口的横向扩张量和断口的形貌具有较好的对应关系。     

X120管线钢回火过程中断口分离问题研究

针对一种高强度X120管线钢高温回火条件下出现的夏比冲击试样断口分离现象。利用扫描电镜、透射电镜及冲击试验机等,从磷、硼、锰等元素的偏析,晶界处第二相如碳化物、合金析出物等的析出及长大角度进行讨论分析。研究结果表明：随回火温度升高,断口分离加剧,分离平均长度及数量增加。夏比冲击功降幅达60％;断口分离先于主断口形成,导致试验钢表面能增加,刚度、主断口裂纹形成功及裂纹扩展功下降;磷、硼、锰等元素在晶界偏聚引起的回火脆性导致分离裂纹产生,夹杂物对分离起促进作用,尺寸较大的第二相弱化了晶界强度。     

Characterization of a second member of the sentrin family of ubiquitin-like proteins

Sentrin is a novel ubiquitin-like protein that can be conjugated to other proteins in a manner analogous to ubiquitination. Two additional cDNA sequences that encode proteins highly homologous to sentrin have been reported to GenBankTM. It is not known whether these sentrin-like proteins could also function as protein modifiers. In this report, a second member of the sentrin family was characterized in detail. Sentrin-2 is a 95-amino acid polypeptide that is 46% identical and 66% homologous to sentrin-1. Northern blot analysis showed that the sentrin-2 message was expressed in all tissues, but was barely detectable in the liver and placenta. The ability of sentrin-2 to conjugate to other proteins was tested by expressing hemagglutinin epitope-tagged sentrin-2 in COS cells. Western blot analysis showed that sentrin-2 could be transferred to other proteins in a pattern similar to that of sentrin-1 conjugation and had similar C-terminal processing. We further showed that both sentrin-1 and sentrin-2 could covalently modify RanGAP1, a Ran GTPase-activating protein critically involved in nuclear transport. Immunocytochemical analysis showed that sentrin-2 derivatives were highly enriched in the nucleus. Taken together, our results demonstrate that sentrin-2 is another protein modifier for the sentrinization pathway.     

Toward an Understanding of the Determinants of Anger.

Research bearing on several popular conceptions of the major determinants of anger arousal indicates that the particular appraisals often identified as causes of anger frequently only serve to affect the intensity of the anger that is generated. Research into effects of physical pain or other physically unpleasant conditions or involving social stresses suggests that decidedly aversive conditions are a major spur to anger. Experiments are also reviewed showing that anger-related muscular movements can also lead to anger-related feelings, memories, cognitions, and autonomic responses. Alternative explanations for the findings are discussed. The authors urge emotion theorists to widen their methodology and analyses so that they give careful, detailed attention to the many different factors that can influence anger. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biochemical analysis of airway aspirates of newborns

We measured contents of tracheobronchial and alveolar components contained in the newborn airway aspirates (NAA) obtained from 54 healthy newborns, with bronchoalveolar lavage fluid (BALF) and bronchial lavage fluid (BLF) from healthy adults, and with mucoid sputum from adults with chronic bronchitis as controls. Fucose (a parameter of tracheobronchial mucus mucoprotein) and tryptase activity were used as tracheobronchial components, and pulmonary surfactant apoprotein A (SP-A) as an alveolar component. The ratio of the content of each component to that of total protein (TP) was compared among NAA, BLF, BALF, and the mucoid sputum. The SP-A/TP ratio in the NAA was similar to that in BLF but 1/24 of that in BALF. The fucose/TP ratio in NAA was about 1/2 of that in BLF and about 6 times higher than that in BALF. The tryptase/TP ratio in NAA was about twice that in BLF and about 80 times that in BALF. The ratios of the above components to TP in the mucoid sputum were closer to those in NAA and BLF than those in BALF. These results suggest that NAA contain both tracheobronchial and alveolar components, and their contents of the formers are larger than those of the latters, and that NAA may be useful for diagnosing pathologic conditions in the airway of newborns, and for comparing the biological defence mechanism between newborns and adults.     

Visual assessment of the accuracy of retrospective registration of MR and CT images of the brain

In a previous study we demonstrated that automatic retrospective registration algorithms can frequently register magnetic resonance (MR) and computed tomography (CT) images of the brain with an accuracy of better than 2 mm, but in that same study we found that such algorithms sometimes fail, leading to errors of 6 mm or more. Before these algorithms can be used routinely in the clinic, methods must be provided for distinguishing between registration solutions that are clinically satisfactory and those that are not. One approach is to rely on a human observer to inspect the registration results and reject images that have been registered with insufficient accuracy. In this paper, we present a methodology for evaluating the efficacy of the visual assessment of registration accuracy. Since the clinical requirements for level of registration accuracy are likely to be application dependent, we have evaluated the accuracy of the observer's estimate relative to six thresholds: 1-6 mm. The performance of the observers was evaluated relative to the registration solution obtained using external fiducial markers that are screwed into the patient's skull and that are visible in both MR and CT images. This fiducial marker system provides the gold standard for our study. Its accuracy is shown to be approximately 0.5 mm. Two experienced, blinded observers viewed five pairs of clinical MR and CT brain images, each of which had each been misregistered with respect to the gold standard solution. Fourteen misregistrations were assessed for each image pair with misregistration errors distributed between 0 and 10 mm with approximate uniformity. For each misregistered image pair each observer estimated the registration error (in millimeters) at each of five locations distributed around the head using each of three assessment methods. These estimated errors were compared with the errors as measured by the gold standard to determine agreement relative to each of the six thresholds, where agreement means that the two errors lie on the same side of the threshold. The effect of error in the gold standard itself is taken into account in the analysis of the assessment methods. The results were analyzed by means of the Kappa statistic, the agreement rate, and the area of receiver-operating-characteristic (ROC) curves. No assessment performed well at 1 mm, but all methods performed well at 2 mm and higher. For these five thresholds, two methods agreed with the standard at least 80% of the time and exhibited mean ROC areas greater than 0.84. One of these same methods exhibited Kappa statistics that indicated good agreement relative to chance (Kappa > 0.6) between the pooled observers and the standard for these same five thresholds. Further analysis demonstrates that the results depend strongly on the choice of the distribution of misregistration errors presented to the observers.     

Improving the lives of millions of school children.

R. Fulghum (1993) contended that all he really needed to know, he learned in kindergarten. This finding does not generalize to predoctoral-postdoctoral education and school-based action researchers. After 20 years, the author's current aspiration is to collaborate with others to disseminate research-based social and emotional learning programs that improve the lives of millions of school children. High-quality graduate and postdoctoral training inspired this commitment. However, realistically speaking, ongoing early- and midcareer training are needed to achieve it. This author describes 2 sets of advanced learning experiences that strongly affected his current activities. He draws implications from these experiences to encourage more support for the early- and midcareer training of school-based action researchers. The address also highlights several priorities that midcareer scientists should address to advance the positive impact that psychology has on the lives of children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Identification of two minor subunits in the pilus of Haemophilus influenzae

Haemophilus influenzae type b (Hib) organisms produce pili, which mediate attachment to human cells and are multimeric structures composed of a 24-kDa subunit called pilin or HifA. Although pili from other organisms contain additional proteins accessory to pilin, no structural components other than pilin have been identified in Hib pili. Previous analysis of a Hib pilus gene cluster, however, suggested that two genes, hifD and hifE, may encode additional pilus subunits. To determine if hifD and hifE encode pilus components, the genes were overexpressed in Escherichia coli and the resulting proteins were purified and used to raise polyclonal antisera. Antisera raised against C-terminal HifD and HifE fragments reacted with H. influenzae HifD and HifE proteins, respectively, on Western immunoblots. Western immunoblot analysis of immunoprecipitated Hib pili demonstrated that HifD and HifE copurified with pili. In enzyme-linked immunosorbent assays, antisera raised against a recombinant HifE protein that contained most of the mature protein reacted more to piliated Hib than to nonpiliated Hib or to a mutant containing a hifE gene insertion. Immunoelectron microscopy confirmed that the HifE antiserum bound to pili and demonstrated that the antiserum bound predominantly to the pilus tips. These data indicate that HifD and HifE are pilus subunits. Adherence inhibition studies demonstrated that the HifE antiserum completely blocked pilus-mediated hemagglutination, suggesting that HifE mediates pilus adherence.     

Quantitative analysis of the immunopotency of genetically transfected dendritic cells

Dendritic cells (DCs) instruct and activate a naive immune system to mount a response toward foreign proteins. Therefore, it has been hypothesized that an ideal vaccine strategy would be to directly introduce genes encoding antigens into DCs. To test this strategy quantitatively, we have compared the immune response elicited by a genetically transfected DC line to that induced by a fibroblast line, or standard genetic immunization. We observe that a single injection of 500-1,000 transfected DCs can produce a response comparable to that of standard genetic immunization, whereas fibroblasts, with up to 50-fold greater transfection efficiency, were less potent. We conclude that transfection of a small number of DCs is sufficient to initiate a wide variety of immune responses. These results indicate that targeting genes to DCs will be important for controlling and augmenting the immunological outcome in genetic immunization.     

Test of the mention theory of irony.

Argues that the traditional theory of irony, which assumes that an ironist uses a figurative meaning opposite to the literal meaning of the utterance, is inadequate and presents an alternative theory that assumes that the ironist mentions the literal meaning of the utterance and expresses an attitude toward it. The 2 theories make testable predictions about the conditions under which irony is perceived: The mention theory requires antecedent material for the ironist to mention, whereas the standard theory does not. A reading comprehension test, given to 24 undergraduates, involved anecdotes that satisfied the traditional criterion for irony but could include or omit antecedents for echoic mention. Results support the mention theory of irony in that Ss did not perceive a plausible nonnormative utterance to be ironic unless it echoed some antecedent use. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)