烧结钕铁硼的力学性能研究现状

分析了烧结钕铁硼呈脆性的原因，介绍了烧结钕铁硼的力学性能研究现状以及研究烧结钕铁硼力学性能的重要性。     

块状烧结钕铁硼废料的氢处理回收技术研究进展

块状烧结钕铁硼废料的主要来源包括烧结钕铁硼机加工过程中形成的边角料和各类报废产品中回收的废料。这种废料基本保持了烧结钕铁硼固有的成分和微结构,如果采用湿法冶金工艺加以回收,不仅工艺过程复杂、回收成本高,而且可能对环境造成污染。对此,不同研究者经过努力开发出了多种短流程、低成本、高效率的块状烧结钕铁硼废料的氢回收技术。本文介绍了利用氢气回收块状钕铁硼烧结废料的原理、工艺流程及当前的研究现状。     

钴含量对烧结钕铁硼居里温度及磁性能影响规律研究

与烧结钐钴磁体相比,烧结钕铁硼稀土永磁具有优异的室温磁性能和力学性能,但其居里温度较低,只有310℃左右,限制了其在耐高温磁应用领域的使用推广。钴元素部分取代钕铁硼中的铁元素可以提高钕铁硼永磁体的居里温度,传统的钴添加方式会使磁体中形成铁钴软磁相,从而造成磁体的矫顽力大大降低。本文研究了不同钴添加量对钕铁硼磁体物相、居里温度和磁性能的影响规律,结合Al、Ga、Cu等元素对钕铁硼永磁体晶界相物相结构的协同调控作用,避免了钴元素取代铁元素过程中Fe-Co软磁相的产生。本研究制备的高钴含量钕铁硼磁体矫顽力高H_cj>28kOe,居里温度T_c>450℃,剩磁温度系数|α|20℃～100℃<0.078%/℃,矫顽力温度系数|β|20℃～100℃<0.55%/℃。     

烧结钕铁硼磁性性能提升研究进展

烧结钕铁硼（Nd-Fe-B）系永磁材料,作为现今社会的主流永磁材料,因价格相对较低、应用范围广泛、磁性性能突出而被广泛应用。为满足现代科学向轻量化和小型化发展的目标,促进稀土资源综合平衡利用,企业不仅需要最大幅度降低制造成本,还要保证烧结钕铁硼磁体的各项磁性能符合社会需求。本文针对烧结钕铁硼成品的组成、各向异性、矫顽力和磁能积等磁性性能,结合现阶段主要采用晶界扩散、晶界掺杂和晶粒细化三大方式改善钕铁硼磁性性能的主流方式,通过对相关磁体磁性性能提升研究近况的分析,探索工业中提升烧结钕铁硼磁性材料磁性性能的可能性与研究方向。     

烧结钕铁硼的研究与应用进展

从配方、添加元素和制备工艺方面概述了烧结钕铁硼永磁材料的研究现状,介绍了该材料在相关领域的应用进展。通过对比分析,展望了我国烧结钕铁硼永磁材料的研究应用方向。     

低失重烧结钕铁硼磁体的研究进展

烧结钕铁硼永磁材料被发明以来,以其优越的磁性能得到了广泛的应用,目前成为永磁产业的支柱。但是其耐腐蚀性能差,大大限制了其使用范围。因此,近20多年来如何改善其抗腐蚀性能成为烧结钕铁硼材料生产和使用的重要问题。总结了烧结钕铁硼腐蚀失重的机制,制备低失重烧结钕铁硼的方法和工艺,对如何提高烧结钕铁硼磁体的耐腐蚀性,降低腐蚀失重进行了综述。从磁体成分设计和微观结构方面总结了几条提高烧结钕铁硼磁体耐蚀性的原则,其关键是对晶界相的成分和微观结构进行合理的控制。     

钕铁硼作为智能高速公路导航磁体的研究

模拟高速公路路面状况,对高、中性能4种烧结钕铁硼进行了冷、热震实验和振动实验,认为烧结钕铁硼永磁体可以作为智能高速公路导航用信号源的选材参考,且烧结钕铁硼的微观结构对信号源的稳定性有重要影响.     

烧结钕铁硼材料外磁场高温耐久测试

随着烧结钕铁硼的不断发展,其在电机上的运用也越来越广泛。烧结钕铁硼永磁材料优异的磁性能和稳定的温度性将对电机的正常运作起着至关重要的作用。本文从外磁场高温耐久这项指标评估烧结钕铁硼的性能指标。     

烧结钕铁硼永磁材料制备工艺的研究进展

对当前烧结钕铁硼永磁体制备工艺中速凝铸带、氢碎、烧结和热处理以及添加合金元素等工序进行了介绍,并对其研究进展进行综述。同时,对烧结钕铁硼永磁体行业可能的发展方向进行了展望。     

烧结钕铁硼二次资源的回收利用

本文介绍了烧结钕铁硼二次资源的产生，回收利用的研究现状及其意义。     

Distribution of elements during the formation of sintered alloys of the system W-Ni-Fe

Summary A study of the distribution of elements in tungsten-nickel-iron alloys, based on the X-ray spectral analysis of mictovolumes, demonstrated that the addition of iron to these alloys affects the mutual solubility of tungsten and nickel. Compared with tungsten-nickel alloys, those containing iron exhibit a narrower heterodiffusion front. The distribution of iron in a tungsten grain remains constant irrespective of alloy composition and more uniform in spite of its solubility, which is five times higher than that of nickel in alloys with the same proportions of elements in the binder.The information obtained on the distribution of elements between the phase constituents of these alloys and a subsequent study of the crystalline structure of these phases may provide answers to a number of questions concerning the formation of these alloys and the nature of their strength.     

Stirring the hearts of followers: Charismatic leadership as the transferal of affect.

In 2 studies, the authors found that leader charisma was positively associated with followers' positive affect and negatively associated with followers' negative affect. The authors hypothesized that leaders' positive affect, positive expression, and aroused behavior will mediate these relationships. The results of their lab study suggest that leaders' positive expression and aroused behavior mediated these relationships. A field study showed that firefighters under the command of a charismatic officer were happier than those under the command of a non-charismatic officer and that these relationships were mediated by the leader's positive affect and a tendency to express positivity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Changes of creatine kinase gene expression in rat heart post-myocardial infarction

This article analyzes social aspects in the incorporation of new information and communications technologies in public health academic institutions. To demarcate the study of these processes and demonstrate the close relationship between their social and technical aspects, the study employs concepts pertaining to "intellectual technologies" and a "critical theory of technology". Theoretical and methodological elements are identified to approach the implementation dynamics of electronic networks in public health institutions, through a discourse analysis of their social actors and the various meanings they attribute to such dynamics Considering discourse as an expression of the relations created during these implementation dynamics, the study seeks a proposal for the ways by which these relations might influence the social and technical dimensions of digital networks.     

Toward a general model of self-regulated study: An analysis of selection of items for study and self-paced study time.

People of all ages are more likely to choose to restudy items (or allocate more study time to items) that are perceived as more difficult to learn than as less difficult to learn. Existing models of self-regulated study adequately account for this inverse relation between perceived difficulty of learning and these 2 measures of self-regulated study (item selection and self-paced study). However, these models cannot account for positive relations between perceived difficulty of learning and item selection, which are demonstrated in the present investigation. Namely, in Experiments 1 and 2, the authors described conditions in which people more often selected to study items judged as less difficult than as more difficult to learn. This positive relation was not demonstrated for self-paced study, which was always negatively correlated with judged difficulty to learn. In Experiments 3 through 6, the authors explored explanations for this dissociation between item selection and self-paced study. Discussion focuses on a general model of self-regulated study that includes planning, discrepancy reduction, and working-memory constraints. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavior modification of studying through study skills advice and self-control procedures.

Investigated the efficacy of 2 behavioral self-control procedures as additions to the typical treatment for college students' study Black skills advice. A between-Ss pyramid design was used with 108 undergraduates, with the pyramid entailing combinations of self-control procedures as treatment additions to the study skills advice. The 2 control and 4 treatment groups indicate (a) family (b) no-treatment control, (c) study skills advice, (d) study skills advice plus stimulus control, (e) study skills advice plus self-monitoring, and (f) study skills advice plus stimulus control plus self-monitoring. Treatments were delivered primarily via typed handouts. In terms of course exam scores, it was predicted that self-monitoring would be an effective treatment addition to study skills advice would be superior to the control groups and that these controls would be equivalent. Results support these predictions. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Histologic and immunologic study of the testis after ligation of the vas deferens in dogs

We wanted to study the effect of bilateral ligature and section of the deferentia of 12 dogs from the histological and immunological aspects. We looked for circulating anti-sperm antibodies and anti-basal membrane of the testes antibodies at the same time as histological study to find out what happened to these lesions after epididymo-deferential anastomosis had been carried out 16 weeks later. The histological lesions (disappearance of exfoliation of the germ cells and of necrobiosis of these cells) disapperared after anastomosis. Anti-basal membrane antibodies were never found. Anti-testicular circulating auto-antibodies were never found. Anti-sperm antibodies appeared between 1 and 5 months after ligature and then disappeared a few months later. Failures to fertilise after epiddidymo-deferential anastomoses therefore do not seem to be due to these two factors.     

Age differences in the allocation of study time account for age differences in memory performance

How aging affects the utilization of monitoring in the allocation of study time was investigated by having adults learn paired associates during multiple study-test trials. During each trial, a subject paced the presentation of individual items and later judged the likelihood of recalling each item on the upcoming test; after all items had been studied and judged, recall occurred. For both age groups in Study 1, (1) people's judgments were highly accurate at predicting recall and (2) intraindividual correlations between judgments (or recall) on one trial, and study times on the next trial were negative, which suggests that subjects utilized monitoring to allocate study time. However, the magnitude of these correlations was less for older than for younger adults. Study 2 revealed that these differences were not due to age differences in forgetting. Results from both studies suggest that older adults do not utilize on-line monitoring to allocate study to the same degree as younger adults do, and that these differences in allocation contribute to age deficits in recall.     

Prevention of indwelling central venous catheter sepsis

In an attempt to decrease the incidence of central venous catheter sepsis in children with cancer, we conducted a study to evaluate the benefit of adding broad-spectrum antibiotics to the catheter "flush solution." In a prospective, placebo-controlled, double-blinded, randomized trial, 69 children with different types of malignancies were studied. The central venous catheters in these children were flushed with either the standard solution (normal saline + 100 U/ml of heparin) or the study solution (25 microgram/ml of both amikacin and vancomycin added to the standard solution). At the conclusion of the study, 64 children with a total of 67 indwelling central venous lines were assessable. The total catheter days on study were 20,700 days, with a median of 323 catheter days per patient. We documented 10 events of catheter-related infections (0.49 events/1,000 catheter days at risk). Five of these events were catheter-related sepsis (0.24 sepses/1,000 catheter days): two were fungal and three were bacterial. Due to the low incidence of catheter-related sepsis in this study, no statement regarding the prophylactic use of antibiotics could be made. The extremely low rate of catheter-related sepsis reported herein may be retrospectively attributed to continuous staff education regarding aseptic techniques in handling these catheters. Staff education is essential, and probably the most effective factor in preventing catheter-related sepsis.     

Guidelines on sodium lauryl sulfate (SLS) exposure tests. A report from the Standardization Group of the European Society of Contact Dermatitis

This report reviews the clinical and histopathological reactions caused by sodium lauryl sulfate (SLS), and the non-invasive methods that can characterize these reactions. Furthermore, SLS exposure techniques and factors that may influence the outcome of these exposures are discussed. Finally, guidelines are introduced for each exposure technique in order to have a uniform approach to SLS testing in man. Since different study aims warrant different testing conditions, we have proposed 2 categories, namely susceptibility testing and provocative testing, tailored to the aim with which the study is performed.     

Contextual effects of bilingual programs on beginning reading.

This study of 1,338 Spanish-speaking 1st graders examined contextual effects of bilingual programs on reading comprehension and the effect of language of instruction within these contexts. The study included 128 classrooms in 32 schools located in border Texas and in urban Texas and California. These classrooms used either English immersion or Spanish maintenance bilingual programs. Detailed observations of teachers' instructional language were made, sampled within the year. The analyses allowed classroom-level differences to be separated from student-level differences, and for Spanish and English passage comprehension to be considered simultaneously. While mean differences between programs were reduced for English passage comprehension, maintenance programs still outperformed immersion programs in Spanish. Results also indicated large program and locale covariance differences at the classroom level, implying important differences in how these programs operate in these locales. (PsycINFO Database Record (c) 2010 APA, all rights reserved)