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161.
传统的烧结法,经850℃、980℃预烧和1000℃-1125℃烧结制备了CaCu3Ti4O12巨介电常数陶瓷.通过X射线衍射(XRD)对体系进行了结晶性能和形貌测试,用阻抗分析仪对试样在50—300K范围内的介电性能进行了测试.研究结果表明:CaCu3Ti4O12的介电常数直接受材料的结晶程度、晶粒大小及致密度控制.通过改善预烧粉末先驱体的结晶程度、提高材料的晶粒尺寸和致密度、改善烧结样品的结晶程度可以获得性能优良的材料.结晶完整,晶粒尺寸大及致密度高的CaCu3Ti4O12在较大的温区范围具有高的介电常数. 相似文献
162.
实施用科研加快建设合格本科院校的战略举措 总被引:1,自引:0,他引:1
根据从专科转向建设本科院校的实践,本文首先讨论了科研在高校中的作用,接着阐述了科研工作的层次性特点,然后简述了用科研手段来加快由专科向本科转变步伐的可行性,最后就如何实施此项战略举措开展了较深入的探讨。所以,本文可能对于丰富在专科基础上快速建设合格本科院校的理论与实践具有意义。 相似文献
163.
对新硼试剂3-甲氧基-甲亚胺H与硼显色反应体系研究结果表明,在pH=5的醋酸-醋酸铵缓冲体系中,硼与3-甲氧基-甲亚胺H在常温下形成2:3的黄绿色配合物,配合物稳定24h以上,λmax=410nm,ε550=6.82×104cm·mol-1·L-1,硼含量在0~2.5μg/25mL范围符合比耳定律. 相似文献
164.
中国手机媒体发展前景分析 总被引:3,自引:0,他引:3
匡文波 《南京邮电大学学报(社会科学版)》2006,8(3):19-23
分析了日本I-MODE取得巨大成功的原因和不足之处,指出无论是从技术上还是从企业模式上,手机媒体在中国的发展都不可能直接拷贝I-MODE模式,只能以I-MODE为借鉴。中国电信发展迅速,手机媒体在中国现阶段发展的重点是手机短信,手机短信市场巨大,但在发展中也存在着一些问题,主要有虚假与不良信息传播、侵犯个人隐私、信息垃圾、信息安全等。然而可以预见,随着3G在中国的逐渐普及以及相关法规的完善,手机媒体将实现网络化、宽带化,将带来一个巨大的媒体市场。 相似文献
165.
尚靖 《天津市财贸管理干部学院学报》2004,6(3):43-47
当今的世界是网络的世界,数以万计的人们通过互联网来传递信息,实现办公。因此,如何保证网络的安全成为人们日益关注的问题。IPSec就是在IPV4数据包结构上增加的一种网络安全性服务,使网络实现了安全通讯。 相似文献
166.
167.
针对当前Pro/E软件教学中的问题,提出将3D打印技术引入课程教学,以增强教学效果。给出了3D打印与Pro/E软件教学相结合的过程,并给出产品建模及3D打印教学的实例。实施结果表明,将3D打印技术引入到Pro/E课程,能提高学生学习兴趣,使学生掌握从产品设计建模到手板制作所需的各项技能。 相似文献
168.
Reforming against all odds: Multi‐pillar pension systems in the Czech Republic and Romania 下载免费PDF全文
Attempts to replace pay‐as‐you‐go pension schemes with private funded systems came to a halt in Central and Eastern Europe after 2005. However, more recently, the region has witnessed two belated reformers: the Czech Republic and Romania. Both countries decided to partially privatize pensions despite the rising tide of evidence concerning the challenges associated with the policy. We argue that while part of the domestic political elite remained supportive of private funded pensions, the difficulties experienced by earlier reformers and reduced support from International Financial Institutions led to the adoption of small funded pension pillars. Such cautious attempts at privatization might become more common in the future as large reforms have proven politically unsustainable. 相似文献
169.
Bernard H. Casey 《International social security review》2014,67(1):27-48
As part of their strategy for economic and monetary union, European governments committed themselves to fiscal discipline – particularly by placing limits on annual deficits and on public debt. Subsequently, and as they sought to respond to the “current crisis”, they embraced the view that only if public finances were kept under control would sustainable recovery be possible. Rules of fiscal governance were strengthened. To help them meet these rules, the governments of many member States of the European Union made changes to their pension systems or to funds they had established specifically to pay the costs of population ageing. The intention was not to cut retirement benefits or to improve the efficiency of the relevant pension schemes and institutions. Rather, it was to free up resources immediately. Funded pension schemes and pension funds were treated like “piggy banks” that were raided when times became hard. Moreover, the policies pursued succeeded in meeting their objectives only because the system of national accounts according to which outcomes are judged does not recognize the way in which most of the fiscal gains are matched by future fiscal liabilities. 相似文献
170.
This paper simulates the distributional impact of the Russian personal income tax (PIT) following the flat tax reform of 2001 using data from the Russian Longitudinal Monitoring Survey. I decompose the change in the distribution of net income into a direct (tax) effect and an indirect effect. The indirect effect is further decomposed into evasion and productivity effects using existing estimates of these respective elasticities. As expected, the direct tax effect increased net income inequality. Changes in the pre-tax distribution (indirect effect), on the other hand, had a large negative impact on inequality thus leading to an overall decline in net income inequality. I also find that the tax-induced evasion response increased reported net income inequality while reducing consumption inequality. To the extent that consumption approximates actual income, these results demonstrate that the flat tax reform had a much smaller effect on actual income inequality than on reported income inequality. More importantly, relative to non-tax factor, the reform had little overall effect on income inequality. This suggests that objection to flatter tax schedules on the grounds of income inequality is mostly misguided, especially in transitional countries with high levels of evasion. 相似文献