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甲氧头孢中间体7-MAC的合成工艺改进 被引量:5
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作者 刘沫毅 杨琰 +1 位作者 刘宏林 王文峰 《化学试剂》 CAS CSCD 北大核心 2009年第2期146-148,共3页
以7-ACA为原料制备7β-氨基-3-(1-甲基-1H-四唑-5-硫甲基)-3-头孢烯-4-羧酸,并以二苯甲酮为原料经过两步反应制备二苯重氮甲烷,然后再经过二苯甲基保护、缩合、氧化、加成以及取代等5步反应制备了标题化合物。通过核磁共振氢谱确证其化... 以7-ACA为原料制备7β-氨基-3-(1-甲基-1H-四唑-5-硫甲基)-3-头孢烯-4-羧酸,并以二苯甲酮为原料经过两步反应制备二苯重氮甲烷,然后再经过二苯甲基保护、缩合、氧化、加成以及取代等5步反应制备了标题化合物。通过核磁共振氢谱确证其化学结构,总收率为32.3%(以7-ACA为基准)。该方法原料易得,操作简单,收率稳定,具有工业化的价值。 展开更多
关键词 甲氧头孢菌素 7-ACA 二苯重氮甲烷 过氧化镍 7-MAC
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Effect of hydrogen peroxide concentration on surface properties of Ni-Cr alloys
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作者 何美凤 王浩 +2 位作者 江鸿 赵素 潘登 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第5期1353-1358,共6页
The effect of concentration of hydrogen peroxide (H2O2) on the surface properties of Ni-Cr alloys was studied. Surface roughness and surface morphology of Ni-Cr alloys were evaluated by surface profiler and scanning... The effect of concentration of hydrogen peroxide (H2O2) on the surface properties of Ni-Cr alloys was studied. Surface roughness and surface morphology of Ni-Cr alloys were evaluated by surface profiler and scanning electron microscopy after being immersed in different concentrations of H2O2 for 112 h. Surface corrosion products of Ni-Cr alloys were analyzed by photoelectron spectrograph after being immersed in 0% and 30% H2O2. The order of increasing surface roughness of Ni-Cr alloys after being immersed in different concentrations of H2O2 was 0〈3.6%〈10%〈30%. As the concentration of hydrogen peroxide increased, the surface roughness of Ni-Cr alloys increased and the surface morphology showed different degrees of corrosion. According to the XPS results, the corrosion products formed on the outmost surface layer of the studied samples are Ni(OH)2 and BeO. 展开更多
关键词 hydrogen peroxide (H2O2) dental Ni-Cr alloys surface roughness surface morphology surface corrosion products
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Experimental study by online measurement of the precipitation of nickel hydroxide: Effects of operating conditions 被引量:2
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作者 Weiwei E Jingcai Cheng +1 位作者 Chao Yang Zaisha Mao 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2015年第5期860-867,共8页
The objective of this work is using the online measurement method to study the process of precipitation of nickel hydroxide in a single-feed semi-batch stirred reactor with an internal diameter ofD = 240mm. The effect... The objective of this work is using the online measurement method to study the process of precipitation of nickel hydroxide in a single-feed semi-batch stirred reactor with an internal diameter ofD = 240mm. The effects of impeller speed, impeller type, impeller diameter and feed location on the mean particle size d43 and particle size distribution (PSD) were investigated, d43 and PSD were measured online using a Malvern Insitec Liquid Pro- cess Sizer every 20 s. It was found that d43 varied between 13 kwh and 26 lain under different operating conditions, and it decreased with increasing impeller diameter. When feeding at the off-bottom distance of D/2 under lower impeller speeds, d43 was significantly smaller than that at D/3. PSDs were slightly influenced by operating conditions. 展开更多
关键词 Nickel hydroxide Precipitation Particle size distribution Online measurement Stirred tank Mixing
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