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排序方式: 共有797条查询结果,搜索用时 15 毫秒
22.
Qulan Zhou Qinxin Zhao Guangjie Zhou Huiqing Wang Tongmo Xu Shien Hui 《Frontiers of Energy and Power Engineering in China》2010,4(3):436-442
The effect of primary air fraction ƒ
1, outer secondary air swirl strength and excess oxygen coefficient on the combustion characteristics of petroleum coke, Hejin
lean coal and Shenmu soft coal are researched on a one-dimensional furnace using a dual channel swirl burner. The results
show that with the increase in primary air fraction ƒ
1, the NO
x
emission concentrations of both Hejin lean coal and petroleum coke increase, and the combustion worsens in the earlier stage,
but the burn-out rate of Shenmu soft coal is improved. The NO
x
emission concentration obtains a minimum value with an increase in ƒ
1. The ignition and burn-out rate of petroleum coke and Shenmu soft coal are optimal when Ωdl is minimum and Ωdl= 0.87, respectively. However, both the NO
x
emission concentration of petroleum coke and Shenmu soft coal are minimum when Ωdl= 1.08. The increase in excess oxygen coefficient delays the ignition of petroleum coke, worsens the combustion condition
and increases the NO
x
emission concentration, but it greatly decreases the NO
x
emission concentration of Shenmu soft coal. 相似文献
23.
Kiyoaki Imoto Kohshin Takahashi Takahiro Yamaguchi Teruhisa Komura Jun-ichi Nakamura Kazuhiko Murata 《Solar Energy Materials & Solar Cells》2003,79(4):459-469
Here, we reported that a new carbon electrode prepared with an activated carbon was superior to a Pt sputtered electrode as the counter electrode of dye-sensitized solar cells. The photovoltaic performance was largely influenced by the roughness factor of carbon electrode. The open-circuit voltage increased by about 60 mV using the carbon counter electrode compared to the Pt counter electrode because of positive shift of the formal potential for I3−/I− couple. 相似文献
24.
Shinji Fukuda Kazuhiko Shimada Noriya Izu Hiroyuki Miyazaki Shoji Iwakiri Kiyoshi Hirao 《Journal of Materials Science: Materials in Electronics》2018,29(14):11688-11698
We observed crack generation and structural changes in electroless nickel–phosphorus (Ni–P) plating layers formed on copper-metalized silicon nitride substrates both during thermal cycling from ? 40 to 250 °C and during storage (not cycling) at 250 °C in order to investigate the effect of the phosphorus contents on crack generation and growth in the Ni–P platings. The used platings contained phosphorus at three different contents: 2.1 wt% [Ni–P(low)], 6.5 wt% [Ni–P(med)], and 10.9 wt% [Ni–P(high)]. The generation time and the amount of cracks were strongly dependent on their phosphorus contents. More cracks appeared after thermal cycling than after storage at 250 °C. In Ni–P(low), cracks were generated after 200 thermal cycles, whereas no cracks were observed even after 250 h of storage at 250 °C. In Ni–P(med) and Ni–P(high), both during thermal cycling and storage at 250 °C, cracks formed during or after crystallization of the amorphous layers. These results suggest that the primary factors affecting the generation of cracks in electroless Ni–P platings are crystallization of the Ni–P platings and repeated changes in thermal stress. 相似文献
25.
Ru Shien TAN Tuan Amran TUAN ABDULLAH Anwar JOHARI Khairuddin MD ISA 《Frontiers in Energy》2020,14(3):545
Presently, the global search for alternative renewable energy sources is rising due to the depletion of fossil fuel and rising greenhouse gas (GHG) emissions. Among alternatives, hydrogen (H2) produced from biomass gasification is considered a green energy sector, due to its environmentally friendly, sustainable, and renewable characteristics. However, tar formation along with syngas is a severe impediment to biomass conversion efficiency, which results in process-related problems. Typically, tar consists of various hydrocarbons (HCs), which are also sources for syngas. Hence, catalytic steam reforming is an effective technique to address tar formation and improve H2 production from biomass gasification. Of the various classes in existence, supported metal catalysts are considered the most promising. This paper focuses on the current researching status, prospects, and challenges of steam reforming of gasified biomass tar. Besides, it includes recent developments in tar compositional analysis, supported metal catalysts, along with the reactions and process conditions for catalytic steam reforming. Moreover, it discusses alternatives such as dry and autothermal reforming of tar. 相似文献
26.
27.
Okihashi M Kitagawa Y Akutsu K Obana H Hori S 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2002,43(6):389-393
Residues of 17 pesticides in agricultural products were determined by LC/MS with an atmospheric pressure chemical ionization (APCI) interface in both positive and negative ion modes. Pesticides were extracted with acetonitrile, and the extracts were cleaned-up with a primary and secondary amine (PSA) mini-column eluted with acetone-hexane (1:1). Rice, orange and potato were spiked with the 17 pesticides at 0.1 microgram/g and analyzed by the proposed method. The average recoveries of these pesticides usually ranged from 70 to 98% and the relative standard deviations were usually around 10%. These results suggested that LC/MS with APCI could be used to determine the residue levels of the 17 pesticides in these crops. 相似文献
28.
Denoising and copy attacks resilient watermarking by exploitingprior knowledge at detector 总被引:2,自引:0,他引:2
Watermarking with both oblivious detection and high robustness capabilities is still a challenging problem. In this paper, we tackle the aforementioned problem. One easy way to achieve blind detection is to use denoising for filtering out the hidden watermark, which can be utilized to create either a false positive (copy attack) or false negative (denoising and remodulation attack). Our basic design methodology is to exploit prior knowledge available at the detector side and then use it to design a "nonblind" embedder. We prove that the proposed scheme can resist two famous watermark estimation-based attacks, which have successfully cracked many existing watermarking schemes. False negative and false positive analyses are conducted to verify the performance of our scheme. The experimental results show that the new method is indeed powerful. 相似文献
29.
Qingwei Fan Shien Hui Qulan Zhou Qinxin Zhao Tongmo Xu 《Frontiers of Chemical Science and Engineering》2010,4(4):404-410
The residual gas and remained raw gas in dual gas resources polygeneration system are quite complex in components (mainly CH4, CO, and H2), and these results to the distinguished differences in combustion reaction. Experimental investigations on basic combustion characteristics of syngas referred above are conducted on a laboratory-scale combustor with flame temperature and flue gas composition measured and analyzed. Primary air coefficient (PA), total air coefficient (TA), and components of the syngas (CS) are selected as key factors, and it is found that PA dominates mostly the ignition of syngas and NO x formation, while TA affects the flue gas temperature after high temperature region and NO x formation trend to be positive as H2/CO components increase. The results provide references for industrial utilization. 相似文献
30.