The relationships of crystal type, crystallization speed, purity, grain size and shape of rare earth carbonate with precipitation and crystallization conditions are very important for the production of rare earth carb...The relationships of crystal type, crystallization speed, purity, grain size and shape of rare earth carbonate with precipitation and crystallization conditions are very important for the production of rare earth carbonate with high efficiency, high quality and low cost. It is necessary for us for further understand the crystallization process mechanism and the factors effect on the crystallization. In the present paper, the crystallization characteristic, composition and crystal phase type of yttrium carbonates or ammonium yttrium carbonates precipitated from yttrium chloride solution using ammonium bicarbonate as precipitant were determined by chemical analysis, X ray powder diffraction and the pH situ determination. It was found that the crystal phase type was dominated by the feed molar ratio of ammonium bicarbonate to yttrium chloride, and the crystallization speed and the crystal composition were also influenced by temperature, feed manner and aging period etc. When precipitating and aging under lower temperature, crystallization is easy to take place in the high feed molar ratio zone, and when increasing temperature, crystallization will take place both in lower and higher feed molar ratio zones. The results show that spherical yttrium carbonate with tengerite type crystal phase can be formed within the temperature 30～70℃ when feed molar ratio of ammonium bicarbonate to yttrium chloride is less than 4, and that a rhombus flake crystal, which possesses the composition of ammonium yttrium quasi double carbonate and a new XRD pattern, is formed when the feed molar ratio is over 4. Their compositions can be represented as (NH4)aY(CO3)b(OH)c·nH2O, a< 1, 1< b< 2, c=3+a-2b. A fine crystal of ammonium yttrium double carbonate with the formula of (NH4)Y(CO3)2·H2O can also be obtained as using an enough amount of ammonium bicarbonate and aging enough time.展开更多
Methoxybenzaldehyde is prepared from the addition-hydrolysis reaction of p-CH 3OC 6H 4MgBr with 1,3-disubstituted benzimidazolium salt. The reaction mechanism is discussed. 1,3-Dialkyl has little influence on the yield.
目的：探索热线心理咨询接线员的言语反应类型及其使用特点。方法：采用定性研究中的类属分析法，选取8份通话时长在30～50 min 的热线心理咨询录音资料，进行逐字稿誊录，对得到的1202个有意义单元进行分析归类。结果：问候性反应、设...目的：探索热线心理咨询接线员的言语反应类型及其使用特点。方法：采用定性研究中的类属分析法，选取8份通话时长在30～50 min 的热线心理咨询录音资料，进行逐字稿誊录，对得到的1202个有意义单元进行分析归类。结果：问候性反应、设置性反应、倾听性反应、跟进性反应和影响性反应是热线心理咨询接线员5类言语反应核心类属。5类言语反应核心类属共包括24项概念类属。接线员均使用了上述5种言语反应类型，倾听性反应与跟进性反应的使用频率最多。在热线心理咨询的开始阶段，接线员主要使用问候性反应和设置性反应；在问题描述阶段，接线员主要使用倾听性反应和跟进性反应；在问题分析阶段，接线员的影响性反应会激增；在结束阶段，接线员主要使用问候性反应和设置性反应。结论：热线心理咨询接线员的言语反应类型包括 5类核心类属和24项概念类属。倾听性反应与跟进性反应在热线心理咨询中的使用频率最多。接线员在咨询的不同阶段，根据助人意图的不同，使用了不同的言语反应类型。展开更多
文摘The relationships of crystal type, crystallization speed, purity, grain size and shape of rare earth carbonate with precipitation and crystallization conditions are very important for the production of rare earth carbonate with high efficiency, high quality and low cost. It is necessary for us for further understand the crystallization process mechanism and the factors effect on the crystallization. In the present paper, the crystallization characteristic, composition and crystal phase type of yttrium carbonates or ammonium yttrium carbonates precipitated from yttrium chloride solution using ammonium bicarbonate as precipitant were determined by chemical analysis, X ray powder diffraction and the pH situ determination. It was found that the crystal phase type was dominated by the feed molar ratio of ammonium bicarbonate to yttrium chloride, and the crystallization speed and the crystal composition were also influenced by temperature, feed manner and aging period etc. When precipitating and aging under lower temperature, crystallization is easy to take place in the high feed molar ratio zone, and when increasing temperature, crystallization will take place both in lower and higher feed molar ratio zones. The results show that spherical yttrium carbonate with tengerite type crystal phase can be formed within the temperature 30～70℃ when feed molar ratio of ammonium bicarbonate to yttrium chloride is less than 4, and that a rhombus flake crystal, which possesses the composition of ammonium yttrium quasi double carbonate and a new XRD pattern, is formed when the feed molar ratio is over 4. Their compositions can be represented as (NH4)aY(CO3)b(OH)c·nH2O, a< 1, 1< b< 2, c=3+a-2b. A fine crystal of ammonium yttrium double carbonate with the formula of (NH4)Y(CO3)2·H2O can also be obtained as using an enough amount of ammonium bicarbonate and aging enough time.
文摘Methoxybenzaldehyde is prepared from the addition-hydrolysis reaction of p-CH 3OC 6H 4MgBr with 1,3-disubstituted benzimidazolium salt. The reaction mechanism is discussed. 1,3-Dialkyl has little influence on the yield.
文摘目的：探索热线心理咨询接线员的言语反应类型及其使用特点。方法：采用定性研究中的类属分析法，选取8份通话时长在30～50 min 的热线心理咨询录音资料，进行逐字稿誊录，对得到的1202个有意义单元进行分析归类。结果：问候性反应、设置性反应、倾听性反应、跟进性反应和影响性反应是热线心理咨询接线员5类言语反应核心类属。5类言语反应核心类属共包括24项概念类属。接线员均使用了上述5种言语反应类型，倾听性反应与跟进性反应的使用频率最多。在热线心理咨询的开始阶段，接线员主要使用问候性反应和设置性反应；在问题描述阶段，接线员主要使用倾听性反应和跟进性反应；在问题分析阶段，接线员的影响性反应会激增；在结束阶段，接线员主要使用问候性反应和设置性反应。结论：热线心理咨询接线员的言语反应类型包括 5类核心类属和24项概念类属。倾听性反应与跟进性反应在热线心理咨询中的使用频率最多。接线员在咨询的不同阶段，根据助人意图的不同，使用了不同的言语反应类型。
