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1.
Mo-Cu合金研究方法进展   总被引:1,自引:0,他引:1  
Mo-Cu材料具有高导热系数和低热膨胀系数及良好的耐热性,因此被广泛用于封接材料、电触头材料和散热器材料.阐述了制备Mo-Cu材料常用的工艺方法及其特点.针对Mo-Cu材料应用的性能要求,概述了制备工艺,指出了制备高致密度Mo-Cu材料并改进其性能是今后的发展方向和研究重点.  相似文献   

2.
Mo-Cu复合材料具有可调控的热膨胀系数、良好的导电导热性能、优异的耐高温性,广泛应用于电触头、电子封装、热沉材料等领域。目前国内外Mo-Cu复合材料制备方法主要有熔渗法、粉末冶金法、液相烧结法等。近年来相关研究学者基于复合粉末原料设计、制备工艺调控及后处理工艺进行Mo-Cu复合材料制备技术的探究,采用激光烧结成型技术、热轧复合技术等方法制备了高致密度、性能优异的Mo-Cu复合材料,为Mo-Cu复合材料制备提供了新思路、新方法,但相关研究技术不够成熟,限制了Mo-Cu复合材料规模化制备与应用,Mo-Cu复合材料未来的研究方向主要是工业化制备性能优异的Mo-Cu复合材料。  相似文献   

3.
烧结参数对钼-铜合金组织和性能的影响   总被引:1,自引:1,他引:0  
通过扫描电子显微镜对合金的微观组织进行了观察,重点对Mo-Cu合金的烧结工艺进行了研究,分析了影响Mo-Cu合金致密度及组织性能的影响因素.结果表明:本试验制备的Mo-Cu合金可获得99%的致密度及优良的组织和性能,为制备高性能的Mo-Cu合金提供参考依据.  相似文献   

4.
通过扫描电镜、透射电镜及X射线衍射等对Mo-Cu复合粉末的粉末形貌、合金化程度及烧结后合金组织结构进行分析,研究了高能球磨后Mo-Cu材料的显微组织及其与陶瓷热膨胀性能匹配的关系。结果表明,采用高能球磨机械合金化和氢气气氛烧结工艺制备的Mo-Cu复合材料,相对密度在98%以上,在室温至700℃热膨胀系数与陶瓷差值在8%。  相似文献   

5.
Mo-Cu合金片的制备及性能研究   总被引:1,自引:0,他引:1  
Mo-Cu合金具有高的导热系数和低的热膨胀系数,被广泛用作热沉材料和电子封装材料.本文对Mo-30Cu合金片的轧制工艺进行了探索,用该工艺制备出了性能优良的Mo-30Cu合金片.  相似文献   

6.
活化元素Ni对Mo-Cu合金性能的影响   总被引:5,自引:0,他引:5  
采用机械活化法制粉、低温烧结和致密化处理工艺,制备了活化元素Ni含量不同的Mo-Cu合金。通过金相组织观察,以及对密度、电阻率、热导率和热膨胀系数测试,研究了Ni的质量分数w(Ni)对Mo-Cu合金的致密性、膨胀系数、导热和导电性能的影响。结果表明:Ni的添加将使Mo-Cu合金的烧结致密化温度降低;Mo-Cu合金热膨胀系数的变化与Al2O3陶瓷的相应变化很接近,但导电和导热性能较差。其显微组织为细小均匀的网络结构,是一种与Al2O3陶瓷很匹配的电子封接材料。  相似文献   

7.
MO-Cu合金的开发和研究进展   总被引:7,自引:0,他引:7  
Mo-Cu合金具有高的热导率和低的线胀系数,被广泛用作热深材料和电子封装材料.本文综述了Mo-Cu合金的基本性能、制备方法、应用和国内外的最新研究进展,概述了其致密化方法,并对其目前存在的问题进行了探讨.  相似文献   

8.
通过自行设计的试验装置以及独特的加料系统,制备了具有连续梯度的Mo/Cu复合材料。经过样品截面体视图、金相组织、能谱扫描、密度、硬度、电导率、热导率等一系列检测分析表明,样品不但在厚度方向上Mo-Cu质量百分含量具有连续梯度,且没有明显的Mo-Cu结合界面,而且各种物理性能也存在着明显的梯度变化。这说明本文制备的样品符合连续梯度功能材料的要求,具有良好的应用前景。  相似文献   

9.
本文以开发Fe-FeAl2O4金属陶瓷材料为目标,针对氧化物陶瓷的高强度、高硬度等性能和金属合金优良的导电性能和机械性能,采用粉末冶金的方法制备出以金属铁为基体,同时添加铁铝尖晶石为陶瓷相的金属陶瓷材料.本文探讨了铁基金属陶瓷材料的制备,研究了烧结温度对于特定比例下的金属陶瓷材料的性能的影响.对不同温度下的试样进行了导热系数、抗折强度的测试,采用SEM、XRD等方法研究试样微观结构与温度的关系.结果表明:在1 200℃温度下的试样,其各方面性能均优于其他温度,从而确定了最佳的烧结温度.  相似文献   

10.
概述了国内外真空开关用触头材料概况,介绍了Mo-Cu(Ag)等几种触头材料的化学成分、性能和应用,并提出了触头材料的发展方向。  相似文献   

11.
12.
Two studies investigated the role of expressive vocal behavior (specifically, speech rate and loudness) in fear and anxiety and in sadness and depression. In the 1st study, participants spoke about personally experienced fear and anxiety-arousing and neutral events using 3 different voice styles: fast and loud, normal, and slow and soft. In the 2nd study, participants spoke about personally experienced sad or depressing and neutral events using the same 3 voice styles. In both studies, the participants' highest levels of subjective affective and cardiovascular (CV) arousal occurred when they spoke about the emotional events in a mood-congruent voice style: fast and loud in the case of fear and anxiety, and slow and soft in the case of sadness or depression. Mood-incongruent voice styles canceled the heightened levels of CV arousal normally associated with these negative emotions. The voice-style manipulation had no significant effect on the participants' levels of CV arousal during the neutral discussions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

13.
Despite the use of multimodal therapy, higher-grade glioma is still uniformly fatal in the adult population. There is a considerable difference between the length of survival in each given patient, even within the same tumor type and malignancy grade group, suggesting that there are factors that might differentially influence outcome. To identify such factors, 107 patients with anaplastic or malignant glioma were retrospectively investigated. Clinical parameters and paraclinical data on the p53, mdm2, and EGFR genes at the DNA or protein level were evaluated by univariate analysis and Cox proportional hazards regression modeling. Kaplan-Meier survival estimation demonstrated that immunohistochemical positivity for mdm2 protein in patients with anaplastic astrocytoma or with glioblastoma multiforme was associated with a shorter survival time (p = 0.02). P53 gene mutations and immunopositivity for the epidermal growth factor receptor (EGFR) protein were not significantly related to poor prognosis. The Cox proportional hazards model revealed immunohistochemical positivity for p53, mdm2, or for both of them, the presence of postoperative irradiation, and the extent of surgical resection of tumor to be variables significantly associated with prolonged survival. EGFR overexpression, age over 60 years, and Karnofsky performance score below 40 points did not significantly shorten survival time. In conclusion, the present study identified immunohistochemically detected mdm2-protein overexpression as a statistically significant negative prognostic parameter in patients bearing anaplastic or malignant glioma. Association analysis of variables revealed a possible correlation between mdm2 and p53, which is also consistent with the biological interaction mode of both proteins in vivo.  相似文献   

14.
BACKGROUND: As aging research increasingly reflects an effort to dissociate true time-driven changes from those that can be improved, sexuality in later life remains largely unexplored. Several problems are evident. There is a lack of normative data, a lack of a conceptual framework relating to the biology, psychology, and sociology of sex, and an attitudinal resistance that obscures the entire topic. METHODS: We conducted a three-part instructional series on major topics involved with sexuality and aging. We surveyed our group of attendees (n 158, average age 68 for males, 65 for females) before and after the series. RESULTS: A remarkably robust sex life was evidenced by both the men and the women, even until advanced old age. Yet, a substantially decreased involvement was reported from 10 years earlier. Despite current activities, people of both sexes wished they were participating even more than they currently were. Impotency was identified as the major negative feature for the men; relationship problems were for the women. A questionnaire 6 months after the series reported improved sexual attitudes, but no change in sexual activities from the earlier survey. CONCLUSION: Sexuality is a major quality-of-life issue which persists into old age. Our study showed that the usual sexual practices reported by our group were not considered by them to be ideal. The intervention of this instructional series provided improved sexual attitudes but not performance. Additional studies are encouraged.  相似文献   

15.
Spondylolysis and spondylolisthesis occur predominantly in the lower lumbar spine. Besides congenital defects such as predisposition of spondylolysis the correlation between competitive sports activities and an increased incidence of spondylolysis is proved. In early stages, complete healing can be achieved by conservative treatment (abstinence from sports activities for 3 months, orthesis). Persistence of pain, neurologic symptoms and progression of vertebral slipping are indications for operative treatment (reconstruction of the isthmus, dorso-ventral spondylodesis). The exercise tolerance depends on the extent of instability, progression of vertebral slipping and clinical symptoms. The limits of exercise tolerance vary among the individual athletes and require the decision of the physician. Backstroke swimming, abdominal and back muscle strengthening exercises, and types of sport involving smooth movements are advisable. Sports education in school is possible without restriction in patients with stable spondylolysis and in those with spondylolisthesis without unfavourable concomitant factors.  相似文献   

16.
OBJECTIVE: To test the validity of Benjamin Franklin's maxim "early to bed and early to rise makes a man healthy, wealthy, and wise." DESIGN: Cross sectional analysis of sleeping patterns in a nationally representative group of elderly people, and longitudinal investigation of mortality. SETTING: Eight areas in Britain (five in England, two in Scotland, and one in Wales). SUBJECTS: 1229 men and women aged 65 and over who in 1973-4 had taken part in a survey funded by the Department of Health and Social Security and for whom data on sleeping patterns, health, socioeconomic circumstances, and cognitive function had been recorded. MAIN OUTCOME MEASURES: Self reported income, access to a car, standard of accommodation, performance on a test of cognitive function, state of health and mortality during 23 years of follow up. RESULTS: 356 people (29%) were defined as larks (to bed before 11 pm and up before 8 am) and 318 (26%) were defined as owls (to bed at or after 11 pm and up at or after 8 am). There was no indication that larks were richer than those with other sleeping patterns. On the contrary, owls had the largest mean income and were more likely to have access to a car. There was also no evidence that larks were superior to those with other sleeping patterns with regard to their cognitive performance or their state of health. Both larks and owls had a slightly reduced risk of death compared with the rest of the study sample, but this was accounted for by the fact that they spent less time in bed at night. In the study sample as a whole, longer periods of time in bed were associated with increased mortality. After adjustment for age, sex, the presence of illness, and other risk factors, people who spent 12 or more hours in bed had a relative risk of death of 1.7 (1.2 to 2.5) compared with those who were in bed for 9 hours. The lowest risk occurred in people who spent 8 hours in bed (adjusted relative risk 0.8; 0.7 to 1.0). CONCLUSION: These findings do not support Franklin's claim. A "late to bed and late to rise" lifestyle does not seem to lead to socioeconomic, cognitive, or health disadvantage, but a longer time spent in bed may be associated with increased mortality.  相似文献   

17.
The constructs of intelligence and ego-resiliency are discussed. The personality implications of "pure intelligence" and "pure ego-resilience" were identified. Intelligence (IQ) was indexed by the Wechsler Adult Intelligence Scale-Revised (WAIS—R) and ego-resiliency by an inventory scale. Residual scores measuring "pure intelligence" and "pure ego-resilience" were correlated with the items of the observer based California Q-sort, used to describe participants. Persons relatively high on ego-resilience tend to be more competent and comfortable in the "fuzzier" interpersonal world; persons defined primarily by raw IQ tend to be effective in the "clearer" world of structured work but tend also to be uneasy with affect and less able to realize satisfying human connections. Gender differences exist in the relations of ego-resilience and intelligence and in their adaptive relevance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

18.
Investigated the effects of modeling and corrective feedback on the conservation of equalities and inequalities, with items spanning 3 stimulus dimensions (length, number, and 2-dimensional space). Ss were 48 kindergartners (24 boys, 24 girls). Brief observation of a model, briefer correction training (joining positive feedback with verbal rule provision), and the combination of observation and correction were all successful in producing learning and, without further training, transfer and retention of conservation. Unlike the controls (who also never correctly answered any equality items), the trained experimental Ss gave evidence of spontaneously generalizing their new learning to a task that required nonverbal behavior to manifest conservation. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

19.
根据深云立交桥梁的检测结果,对该桥目前的整体状况、工作状态,及其使用情况做出综合评价,对桥的病害原因进行了分析,并提出合理的加固方案。  相似文献   

20.
众所周知,国际单位制物质的量采用摩尔(mol)表示,近几年出版的给排水专业书籍,为了与国际单位制接轨,逐渐将摩尔的使用频率不断提高,被给排水技术人员广泛应用的新版给排水设计手册,将表示物质浓度的单位“当量/升”或“毫克当量/升”.改为mol/l或mmol/l,虽然编者对其基本单元定义作了说明,但在实际运用上仍会出现误解,  相似文献   

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