共查询到20条相似文献,搜索用时 434 毫秒
1.
《中国稀土学报》2021,(4)
针对稀土电解槽阳极腐蚀消耗速率快、有效使用时间缩短、残余浪费量大等问题,以8 kA稀土电解槽为研究对象,分析不同时刻阳极电解腐蚀下的变化特征及阳极更换顺序对其腐蚀消耗的影响,以阳极及其不同更换顺序进行电解腐蚀模拟仿真分析,结合实际生产过程阳极腐蚀情况进行对比,找出阳极的腐蚀规律及改善阳极更换顺序。结果表明:阳极腐蚀消耗结果与实际生产中阳极的消耗情况基本吻合,说明在稀土电解槽的电解过程中,阳极上端和下端厚度消耗前期均快于后期,且下端消耗大于上端,液面下端阳极长度消耗则后期快于前期,同时验证了采用阳极对角更换顺序可以有效提高阳极的利用率和延长阳极的更换周期。 相似文献
2.
3.
4.
5.
《中国稀土学报》2015,(6)
通过混合物模型和阳极气泡聚并与破裂模型的耦合求解,引入标准湍流模型,利用流体力学计算软件FLUENT对稀土电解槽内阳极气泡进行数值仿真模拟,并对比分析了不同时间、不同阳极电流密度和不同极距下阴阳两极间的气泡对槽内流体速度场和槽内含气率分布的影响及规律。由计算结果分析可知:稀土电解槽阴阳两极间中上部区域和电解槽槽底区域表现出对称涡旋流动;阳极电流密度相同时,局部涡旋流动随电解时间逐渐增强、径向含气率逐渐增加,并且在电解后期阳极气泡表现出了聚并和破裂的运动状态;电流的增大使槽内流体的湍流强度增强、气泡的聚并和破裂加强;槽内流体的湍流强度和有效热导率在不同阳极电流密度下的分布曲线均呈现4个单峰分布;当阳极电流密度为1.5 A·cm~(-2)时,槽内流体的湍流强度和有效热导率分布较好;极距和阳极电流密度最合适匹配数值分别为82.5 mm和1.5 A·cm~(-2)。 相似文献
6.
7.
《中国稀土学报》2016,(3)
针对6 k A新型Ce电解槽结构,采用数值模拟软件建立该电解槽的电场模型。模拟了在阴、阳极高度相差一定的情况下,同时改变阴、阳极的插入深度从而分析电解槽内电场的变化情况。研究表明:随着阴、阳极插入深度的不断变化,电解槽内部电流密度和槽电压也随之发生变化,阴、阳极插入深度逐渐增加,槽电压逐渐降低,电解槽底部的电压差增加,但电流密度值却逐渐减小,产生热量也会降低,阴、阳极插入深度减少,槽电压越来越高,电解过程中由电流产生的热量就会逐渐增加,电流效率却逐渐降低,因此通过模拟后发现最佳的阴极插入深度约为0.290 m,阳极高度约为0.250 m。通过对电场的模拟,为Ce电解槽开发设计具有很重要的意义。 相似文献
8.
9.
电解过程中阳极的消耗会使电极尺寸和形状发生变化,进而对电场分布产生影响。利用有限元分析软件ANSYS建立了传统6 kA上插阴阳极式稀土电解槽的3D模型,分别研究了电解过程中阳极呈均匀消耗和非均匀消耗两种形态对电场分布的影响。结果表明,随着阳极炭块消耗量的增加,电极下方电压等势线分布呈现下移趋势,且电场强度不断增加;阳极非均匀消耗时槽电压要比均匀消耗高出130 mV左右,非均匀消耗电场强度比均匀消耗电场强度的增加量呈先增加后减小趋势,在阳极消耗26 mm时增加量达到最大值,为10.45 V·m~(-1)。根据电场仿真的结果,在阳极消耗达到50 mm时进行阳极的更换较为合理,并建议在该电解条件下使阳极保持均匀消耗更有利于电解槽的稳定性。 相似文献
10.
11.
Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives. 相似文献
12.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion. 相似文献
13.
N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%). 相似文献
14.
Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones. 相似文献
15.
In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates. 相似文献
16.
Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described. 相似文献
17.
用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在. 相似文献
18.
19.
Jona Mirnik Eva Pušavec Kirar Sebastijan Ričko Uroš Grošelj Amalija Golobič Franc Požgan Bogdan Štefane Jurij Svete 《Tetrahedron》2017,73(24):3329-3337
A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu0 as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than CuI in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT). 相似文献
20.
George E. Magoulas Thomas Garnelis Constantinos M. Athanassopoulos Dionissios Papaioannou George Mattheolabakis Konstantinos Avgoustakis Dimitra Hadjipavlou-Litina 《Tetrahedron》2012,68(35):7041-7049
(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C60, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine. 相似文献