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81.
82.
本文分析了液滴在不互溶的液相介质中上升汽化时的传热和传质,导出了数模,进行了数值求解,获知在泡滴与液相接触的汽液边界处温度下降和浓度升高,存在着溶液的过冷(或过饱和)边界层。实验结果与数模计算结果表明,该模型能够较好地预測液滴汽化的整体特性。 相似文献
83.
The size effect of optical properties of the polycrystalline Ge/Si films prepared by pulse laser deposition (PLD) is investigated
by photoluminescence (PL) and photocurrent (PC) spectra. The size of Ge nanocrystals is precisely controlled by the pulsed
deposition time and then observed by the atomic force microscopy (AFM). The average size of Ge nanocrystals is about 2, 5
and 25 nm for 1, 2 and 3 min deposited sample, respectively. The size effect on optical properties of Ge nanocrystals has
been analyzed by photoluminescence (PL) and photocurrent (PC) spectra. The PL peaks shift from 0.799 eV for 1 min to 0.762 eV
for 3 mins; at the same time, the photocurrent peaks of the films sharply changes from 0.781 eV to 0.749 eV, the shifts of
PL and PC are contributed to the quantum size effect of Ge nanocrystals. 相似文献
84.
Liu Jun-min Zhang Chen Liu Shi 《Frontiers of Electrical and Electronic Engineering in China》2006,1(3):330-333
A new positioning method in mobile networks is presented. Based on the data fusion technology, it processes multi-layer information
fusion for the location estimates achieved by the Chan algorithm, which increases mobile positioning accuracy effectively
by only using measured difference of arriving (TDOA) signals. The method is simple and practical, especially when the location
estimates are corrupted by the non-line-of-sight (NLOS) error. It not only has high positioning accuracy, but also reduces
the location failure probability. Results from computer simulation show that the proposed method is effective in various environments.
__________
Translated from Journal of Dalian University of Technology, 2005, 45(1): 138–141 (in Chinese) 相似文献
85.
卷枝毛霉γ-亚麻酸高产菌株的选育 总被引:2,自引:0,他引:2
对卷枝毛霉(Mucor circinelloides)3.2208进行紫外诱变,采用苏丹黑染色和TTC酶活法进行初筛,摇瓶发酵测定相关指标进行复筛,获得1株γ-亚麻酸(γ-linolenic acid,GLA)产率比出发菌株显著提高的突变株M3,经培养,M3菌体细胞收率为15.20 g/L,油脂含量为20.10%,油脂产率为3.65 g/L,GLA含量占菌体油脂总脂肪酸的17.28%,产率达630.72 mg/L. 相似文献
86.
Transparent La2Hf2O7 (LHO) ceramics were, for the first time, successfully fabricated from combustion-synthesized powders. Nanosized La2Hf2O7 powders were obtained through combustion reaction, using glycine or EDTA as a fuel. The as-made powders were isostatically pressed at 180 MPa and then sintered at 1850 °C for 6 h in hydrogen atmosphere. The resulting ceramics have high optical transmittance. 相似文献
87.
低压省煤器在电站锅炉中的应用 总被引:1,自引:0,他引:1
针对排烟损失大的问题,某些电厂在电除尘器出口加装低压省煤器,用来加热凝结水或热网补水,从而吸收烟气热量,实际测试结果表明,对于节能降耗和保证安全运行均起到了重要作用。 相似文献
88.
Response of seasonal vegetation development to climatic variations in eastern central Asia 总被引:9,自引:0,他引:9
Meteorological records show that central Asia has experienced one of the strongest warming signals in the world over the last 30 years. The objective of this study was to examine the seasonal vegetation response to the recent climatic variation on the Mongolian steppes, the third largest grassland in the world. The onset date of green-up for central Asia was estimated using time-series analysis of advanced very high resolution radiometer (AVHRR) normalized difference vegetation index (NDVI) biweekly composite data collected between January 1982 and December 1991. Monthly precipitation and mean temperature data (1982-1990) were acquired from 19 meteorological stations throughout the grasslands of the eastern Mongolian steppes in China. Our results showed that while the taiga forest north of the Mongolian steppes (>50°N) experienced an earlier onset of green-up during the study period, a later onset was observed at the eastern and northern edges of the Gobi Desert (40°N-50°N). Responses of different vegetation types to climatic variability appeared to vary with vegetation characteristics and spring soil moisture availability of specific sites. Plant stress caused by drought was the most significant contributor to later vegetation green-up as observed from satellite imagery over the desert steppe. Areas with greater seasonal soil moisture greened up earlier in the growing season. Our results suggested that water budget limitations determine the pattern of vegetation responses to atmospheric warming. 相似文献
89.
跨时间序列关联规则分析的高效处理算法 总被引:1,自引:0,他引:1
多元金融时间序列之间是互相影响的。该文就跨时间序列的关联规则挖掘提出一种新方法:ES-Apriori,此方法通过减少数据库扫描次数,优化内存分配,能够高效地分析多元时间序列之间的关联规则。试验表明,用此方法分析中国证券市场的股票时间序列非常有效。 相似文献
90.
DPMAS:一种多主体系统设计方法 总被引:1,自引:0,他引:1
提出一种多主体系统设计方法DPMAS。首先,该方法以对象作为主体实现的基础,以UML作为基本的建模语言,保证了与面向对象方法的延续性。同时,该方法提供了新的图来表示多主体系统中的知识模型和主体间交互模型,并对UML符号进行了一些改进以表示主体特有的概念。 相似文献