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2018-12-19 04:35發(fā)布了問(wèn)答
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蒸餾器的花露蒸取
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2018-11-28 21:17發(fā)布了問(wèn)答
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誰(shuí)有關(guān)于燃燒學(xué)的書籍？跪求?。。。。。。。?！越多越好！?。?！
- 發(fā)一下pdf或是百度云... 發(fā)一下pdf 或是百度云 展開
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2018-11-14 18:00發(fā)布了問(wèn)答
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哪位英語(yǔ)高手幫幫忙，翻譯英語(yǔ)文章！謝謝1
- 英語(yǔ)高手，謝謝了！ThecatalystsupportwasimpregnatedwithacetonesolutionofRuCl3.nH2Ouptorutheniumcontentof4w%，understirringfor6h.Afterconcentrationinarotaryevaporator，theobt... 英語(yǔ)高手，謝謝了！
The catalyst support was impregnated with acetone solution of RuCl3.nH2O up to ruthenium content of 4 w%， under stirring for 6 h. After concentration in a rotary evaporator， the
obtained material was dried in air at 383 K overnight and subjected to preliminary reduction with a 1N2/3H2 stream at 698 K， and then cooled in 1N2/3H2 atmosphere. The potassium promoter was introduced by incipient wet impregnation with KNO3 solution at room temperature with molar ratio of K+ /Ru = 5/1. After stirring for 6 h and infusing for 24 h， the samples were dried in a rotary evaporator at 343K and then dried in the air
at 383K for 12 h. The ammonia synthesis activities of the catalysts with about 35-60 meshes were evaluated by 1N2/3H2 flow of 2100 mL/h at 0.2 MPa from 623 K to 773 K. The
amount of effluent ammonia was determined by titration method.
As we can see from the Table 1， under the same reaction conditions， the catalyst K-Ru/Mg(Al)O exhibited the highest activity， 38.42 mL NH3?h-1?g-1 at 673K， 3 times
more active than K-Ru/MgO， 12.88 mL NH3?h-1?g-1 at 748K. This means that selection of supports takes great effects on the activity of catalysts. The ammonia synthesis activity of
different supports are K-Ru/Mg(Al)O > K-Ru/Mg-Al-Ca(1) > K-Ru/Mg-Al-Ca(2) > K-Ru/Al2O3 > K-Ru/CaO > K-Ru/MgO. The combinatorial supports showed higher activity than single
supports. However， the sequence of temperature corresponding to the highest activity is just opposite to that of the activity. The optimal temperature for K-Ru/Mg(Al)O， 673K， is
the lowest of all， on the contrary， that of K-Ru/MgO is the highest， 748K. The Mg(Al)O has a larger surface area of 140.95 m2?g-1 ， similar to γ-Al2O3， 110-180 m2?g-1 . The other
two combinational supports have little surface areas but higher activities than Al2O3. It suggested that the activity of the catalyst is influenced not only by the dispersion of Ru
crystals but also by the crystal structure of the supports.
Table 1 Ammonia synthesis activities and BET surface areas
Catalyst Optimal activity Highest activity Surface area of support
temperature(K) (NH3/mL?h-1?g-1) (m2?g-1)
K-Ru/MgO 748 12.88
K-Ru/Al2O3 698 23.79
K-Ru/CaO 723 23.22
K-Ru/Mg(Al)O 673 38.42 140.95
K-Ru/Mg-Al-Ca(1) 698 30.75 29.10
K-Ru/Mg-Al-Ca(2) 698 26.12 14.69
Acknowledgments
This work was supported by the NNSF of China (20273053， 20023001 and 29933040)， the 973
Programming (001CB108906) and the NSF of Fujian province (E0310001).
References
1. C. J. H. Jacobsen， S. Dahl， P. L. Hansen et al.， J. Mol. Catal. A， 2000， 163， 19.
2. F. Cavani， F. Trifiro， A. Vaccari， Catal. Today， 1991， 11， 173. 展開
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2017-09-14 02:02發(fā)布了問(wèn)答
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進(jìn)分子蒸餾的樣品需要什么前處理
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2016-08-15 03:42發(fā)布了問(wèn)答
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純凈水是純凈物嗎？
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2016-04-21 21:40發(fā)布了問(wèn)答
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臺(tái)式循環(huán)水真空泵背后的進(jìn)出水口什么作用
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2015-04-04 17:41發(fā)布了問(wèn)答
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唐朝到底有沒有劍南春
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2013-11-07 11:03發(fā)布了問(wèn)答
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【求助】納米二氧化硅溶解在乙醇里，怎么干燥
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2013-03-31 20:29發(fā)布了問(wèn)答
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活性水和純凈水有什么區(qū)別嗎？
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2011-07-11 19:13發(fā)布了問(wèn)答
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求黃芩提取物的具體提取方法，水提還是醇提，說(shuō)具體點(diǎn)，可以加分哦
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2011-01-20 05:31發(fā)布了問(wèn)答
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威士忌一般都用什么做的？小麥嗎？
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2009-10-05 21:18發(fā)布了問(wèn)答
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旋轉(zhuǎn)蒸發(fā)儀先轉(zhuǎn)動(dòng)還是先減壓？
- 使用時(shí)，是應(yīng)該先讓蒸發(fā)瓶轉(zhuǎn)起來(lái)再減壓，還是先靜止減壓再讓蒸發(fā)瓶轉(zhuǎn)？這二者有區(qū)別嗎？... 使用時(shí)，是應(yīng)該先讓蒸發(fā)瓶轉(zhuǎn)起來(lái)再減壓，還是先靜止減壓再讓蒸發(fā)瓶轉(zhuǎn)？這二者有區(qū)別嗎？ 展開
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2008-11-24 09:14發(fā)布了問(wèn)答
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涂裝行業(yè)專業(yè)英語(yǔ)：純水洗和直噴水洗怎么翻譯成英文？
- 純水洗，我看到了pure laundering和washed pure哪個(gè)對(duì)啊？
直噴水洗怎么翻譯呢？急求？謝謝~
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2008-02-15 07:23發(fā)布了問(wèn)答
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純水.凈水.活水.三者的區(qū)別，飲用對(duì)人體的好壞
- 純水.凈水.活水.三者的區(qū)別，飲用對(duì)人體的好壞
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