排序方式： 共有39条查询结果，搜索用时 15 毫秒
1.
纳米晶体二氧化钛非水体系合成和光催化性能 总被引：1，自引：0，他引：1
钛酸丁酯和乙酐在低于100℃非水状态下生成非晶钛氧聚合物，经焙烧得到纳米二氧化钛晶体，焙烧失重46．55％，在314℃～389℃之间失去表面有机基团，389℃～405℃之间转化为锐钛矿型晶体。XRD和TEM研究了晶体颗粒的袁征。用苯胶的光催化降解评价了非水合成的纳米晶体二氧化钛的光催化活性。 相似文献
2.
采用高温固相法，自废旧锂离子电池中回收制备LiAlO2，并采用XRD方法表征了LiAlO2的物相成份。结果表明，900℃培烧2h制备的LiCoO2与Al箔按化学计量比n（Li）：n（A1）=4：5混合均匀后，再在800℃培烧2h后制备的LiAlO2的晶形结构较好。 相似文献
3.
烤烟新品系DL02选育及特征特性研究 总被引：2，自引：0，他引：2
DL02是大理州烟草公司烟叶技术中心种子站于2002年在弥渡县密址镇的红花大金元示范田中选育出的变异株经多年培育而成的烤烟新品系。与当地主栽品种红花大金元相比，DL02的苗期生长势、大田期生长势、生长整齐度、抗病性、产量、产值、上等烟比例、级指、均价、烘烤特性、色素含量及生理抗性指标等11个方面，均优于亲本红花大金元。显现超亲现象。具有更加优良的特性，值得生产中试用。 相似文献
4.
积雪是冰冻圈最重要的组成部分,影响着大气环流和区域水量平衡,对气候变化十分敏感。本文基于2000—2019年MODIS/Terra积雪产品数据,探讨了青藏高原近20年积雪的年内、年际和季节性时空特征及其变化趋势。结果表明：①2000—2019年青藏高原积雪以短期积雪为主,积雪期在1个月及以下时间段内的积雪空间分布范围最广,占积雪总面积的72.91%;积雪期越长,多年平均积雪率（SCR）越高,SCR呈高原四周山脉高,而羌塘高原、江河源区、柴达木-黄湟高中盆地等地低的特点。②2000—2019年积雪面积呈反复的先波动增加再波动减少,距平变化率在-15.97%~11.52%之间。横断山区、帕米尔高原以及羌塘高原大部分地区的SCR呈明显减少趋势;高原四周极大/大起伏高山/极高山区、江河源丘状高山原和江河上游中/大起伏高山区的SCR呈显著增加趋势。③年内积雪面积呈双峰型周期变化趋势,3月和11月达到峰值,8月达到谷值,与该区域多年平均气温、降水等气候因子的年内周期性变化相反。青藏高原冬季积雪分布最广,秋季和春季积雪范围次之,夏季积雪范围最小;2000—2019年,青藏高原东部和南部冬季积雪显著增加、秋季和春季积雪显著减少,青藏高原整体夏季积雪显著减少。④近20年,青藏高原积雪与气温、降水的相关程度均较强,积雪覆盖范围与气温呈负相关关系,与降水呈正相关关系。研究结果有助于掌握青藏高原冰雪融水变化情况,对区域水量平衡和气候变化有重要指示作用。 相似文献
5.
Although age is not supposed to be a criterion for the award of the Nobel Prize, it is commonly believed that it does play a role. Indeed, econometric evidence in this paper also suggests such a role. However, the paper finds that, if there is a preference for older Nobel candidates, this is introduced during the nomination process. The paper actually finds that the Nobel Committee does not favor older nominees and that, if anything, it seems to partially offset the age premium introduced by the nominators. 相似文献
6.
以钛酸丁酯、四丁基氢氧化铵、硝酸铈为原料,采用溶胶一凝胶法合成C—Ce—TiO2光催化剂,经XRD、UV—Vis—DRS表征,在9W日光灯照射下光催化降解农药。结果表明：随着碳掺杂量的增加,微晶粒径减小、禁带能隙降低、对农药的光催化活性增大。 相似文献
7.
金属氧化物沉积法制备钛酸铋钠陶瓷的研究 总被引：1，自引：1，他引：0
张寅 《山东教育学院学报》2008,23(4):75-78
金属氧化物沉积法（MOD）成功地制备了Bi1/22Na1/2TiO3（NBT）基无铅压电陶瓷,样品的X射线衍射（XRD）结果显示其具有较好的结晶性,XRD指标化后的结果表明,晶胞参数的变化,在室温下是赝立方相。通过测量不同退火条件下陶瓷表观密度,得到NBT陶瓷采用MOD法的最大密度可在烧结温度约为1150℃左右。 相似文献
8.
The use of university-industry collaboration in the innovation process is viewed as a major driver of firm competitiveness. The organizational dynamics underlying successful external relationships, however, remain poorly understood. Using longitudinal case studies of 15 innovation projects, we examine how firms with varying degrees of experience in collaborating with universities and public research organizations rely on different social capital dimensions to achieve successful collaborations. We find that experienced firms establish external collaborations on the basis of cognitive social capital, but this basis is reinforced by relational social capital over time. Conversely, less experienced firms initially base their university collaborations on relational social capital, which is reinforced by cognitive social capital over time. Based on these findings, we theorize on the interplay of different dimensions of social capital in university-industry collaborations over time. Our study has important implications for the management of collaborative innovation projects. In particular, it provides guidance to enable less experienced firms to develop successful collaborations with university partners. 相似文献
9.
GM(1,1) and GM(1,1) rolling models derived from grey system theory were estimated using time-series data from projection studies by National Center for Education Statistics (NCES). An out-of-sample forecasting competition between the two grey prediction models and exponential smoothing used by NCES was conducted for education expenditure and school enrollment under the assumption that grey prediction was as promising as NCES's forecasting technique in dealing with univariate time-series data while some other determinants of the variables under examination were excluded. The purpose of this study, therefore, was to verify that the GM(1,1), and GM(1,1) rolling models would provide forecasts that were at least as accurate as the NCES's approach to extrapolating education expenditure and school enrollment. The findings revealed that the forecasting efficiency of GM(1,1) rolling model was superior to exponential smoothing and GM(1,1) model. The results can offer valuable insights and provide a basis for further research in model building for short-term estimation on educational statistics. 相似文献
10.
随着无线网络技术的普及,在有线校园网基础上扩展无线网络已成为组建无线校园网的主流技术之一。简要介绍了IEEE802.11标准协议与无线网络互联设备,阐述无线校园网的实现原则及设计方案,最后结合滁州职业技术学院的实际情况设计了一个无线校园网络的可行方案。 相似文献