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141.
La(C7H5O3)2·(C9H6NO)的合成及热化学研究 总被引:1,自引:0,他引:1
研究由七水氯化镧与水杨酸、8-羟基喹啉反应合成镧与水杨酸、8-羟基喹啉多元混合配合物,并对该配合物进行表征.测定该合成反应的标准摩尔反应焓以及配合物的标准摩尔生成焓.通过红外光谱、元素分析、摩尔电导率、差热热重分析以及化学分析等方法来确定配合物的组成.应用溶解量热法分别测定了七水氯化镧、水杨酸、8-羟基喹啉和配合物在298.15 K、混合量热溶剂(VDMFVEtOHVHClO4=110.5)中的标准摩尔溶解焓.通过设计热化学循环,根据盖斯定律计算了合成反应的标准摩尔反应焓以及配合物的标准摩尔生成焓.该配合物的分子式是La(C7H5O3)283;(C9H6NO).各物质的溶解焓分别为△sH(I○)mLaCl383;7H2O(s),298.15 K]=-96.45±0.18 kJ83;mol-1,△sH(I○)m[2 C7H6O3(s),298.15 K]=14.99±0.17 kJ83;ml-1,△SH(I○)m[C9H7NO(s),298.15 K]=-3.86±0.06kJ83;mdl-1及△S(I○)m[La(C7H5O3)283;(C9H6NO)(s),298.15K]=-117.78±0.11kJ83;mol-1.反应LaCl383;7H2O(s)+2C7H6O3(s)+C9H7NO(s)=La(C7H5O3)283;(C9H6NO)(s)+3HCl(g)+7H2O(1)的标准摩尔反应焓为91.57±0.33 kJ83;mol-1.La(C7H5O3)283;(C9H7NO)(s)的标准摩尔生成焓为△sH(I○)m[La(C7H5O3)283;(C9H6NO)(s),298.15 K]=-2076.5±3.9 kJ83;mol-1. 相似文献
142.
Microstructures of spinodal phases in Cu-15Ni-8Sn alloy 总被引:1,自引:0,他引:1
YanhuiWang MingpuWang BinHong 《北京科技大学学报(英文版)》2005,12(3):243-247
The microstructures of spinodal phases in Cu-15Ni-8Sn alloy were studied by TEM. It was found that when the alloy is completely in a as-quenched state, spinodal decomposition is quick. Ordering appears after spinodal decomposition. The ordered phase with DO22 structure has three variants obtained from coarsening spinodal structure. The reason of ordering appeared after spinodal decomposition is that the content of solute atoms needed by ordering is higher than the average, which can be reached by the composition fluctuation of spinodal decomposition. It was speculated that the morphology of the ordered phase is needle-like. 相似文献
143.
研究了在氢气氛下机械球磨铸态Nd8Fe86B6合金, 使Nd-Fe-B合金发生歧化反应, 随后在一定温度下进行真空脱氢处理, 并通过粉末压制成形制备纳米双相稀土永磁体. 利用X射线衍射 (XRD)、透射电镜(TEM)、以及原子力显微镜(AFM)等测试手段, 对球磨过程中合金粉末吸氢岐化反应以及脱氢过程中相变及粉末形貌进行分析观察. 实验结果表明, Nd8Fe86B6合金中Nd2Fe14B相发生了吸氢并歧化反应, 球磨20h后获得了晶粒大小为10nm左右的Nd2H5、 FeB和α-Fe歧化组织, 氢化及岐化反应对粉末颗粒细化效果明显, 球磨20h后大部分颗粒尺寸约为70nm, 经过真空脱氢处理后颗粒尺寸约为135nm. 研究得出, 对球磨20h并在700℃下进行脱氢再结合处理获得的粉末进行室温下压制成形, 获得了晶粒组织约为25nm左右的复相组织, 通过振动样品磁强计(VSM)测得压制磁体的磁性能最高为 Br=0.72T, Hci=553kA/m, (BH)m=92.5kJ/m3. 相似文献
144.
The inclusion of an expander with work recovery provides two advantages for transcritical CO2 refrigeration cycles: the COP is improved and the exhaust pressure of the main compressor is lowered. Several designs of expanders have been proposed for this application and some prototypes have been tested already. In our laboratory a three-stage expander has been developed, which replaces the throttle valve of the normal refrigeration cycle and expands into the two-phase region. For optimum integration into the overall system it is proposed to install a vapour-liquid separator between the second and third stage of expansion. The vapour is guided back to the third expander stage whereas the liquid is supplied to the cooling stations via thermostatic or electronic expansion valves. 相似文献
145.
H.B. Nahor N. Scheerlinck P. Verboven J. Van Impe B.M. Nicolaï 《International Journal of Refrigeration》2005,28(4):471
In this paper, a controlled atmosphere storage model, developed earlier, is validated using an industrial CA cool storage facility with stepwise product loading strategy. The proposed combined continuous and discrete CA cool storage simulation model was able to represent the step response transients and continuous events, with accuracy less than the observed variability or at best with accuracy level as set by the measurement instrument. Moreover, the handling of discrete/continuous events enabled the implementation of practical operational procedures and to investigate their implication on plant performance/design and directly on the product quality. The model is a valid working model for design and optimization of CA cool storage facilities both with respect to plant performance and final quality of the stored product. 相似文献
146.
W. Wang Z. Ma Y. Jiang Y. Yang S. Xu Z. Yang 《International Journal of Refrigeration》2005,28(5):3611
This paper reports a double-stage coupled heat pumps (DSCHP) heating system, which couples air source heat pump (ASHP) and water source heat pump (WSHP) together. The system is presented for the first time in open literature with the objective to improve the working condition and heating performance of the ASHP under cold environment. A practical project in Beijing firstly installed this system and field test has been performed for one month. The test results indicate that the DSCHP system can be smoothly and efficiently used for heating in cold regions. Compared with the traditional ASHP heating system, the operating characteristics of the DSCHP heating system are greatly improved, demonstrating that the system can offer considerable application potential in cold regions. 相似文献
147.
Temperature–entropy (T–s) diagrams have the unique capability of being able to quantify processes in terms of both the first and second laws of thermodynamics. Although use of generalised T–s diagrams has been made to indicate or represent generalised absorption cycles, with the exception for NH3/water systems, these diagrams have not been specifically tailored to scale to quantify LiBr/water systems. The main barrier for this is that the diagram needs to represent the necessary properties of both the refrigerant (water) and of the solution (LiBr/water). This paper describes the use of the T–s diagram of water extended with additional curves to represent real and ideal LiBr/water absorption cycles. An explanation is provided on several methods available, including details of the thermodynamic justification of the method that was used, to construct the extended diagrams. Finally, the extended T–s diagram is provided with the representation of a real single-effect LiBr/water absorption refrigeration cycle. This should prove to be a valuable tool for design and research engineers to study and optimise LiBr/water chillers. 相似文献
148.
High quality Tl2Ba2CaCu2O8 (Tl-2212) superconducting thin films are prepared on both sides of 2 in. LaAlO3(0 0 1) substrates by off-axis magnetron sputtering and post-annealing process. XRD measurements show that these films possess pure Tl-2212 phase with C-axis perpendicular to the substrate surface. The thickness unhomogeneity of the whole film on the 2 in. wafer is less than 5%. The superconducting transition temperatures Tcs of the films are around 105 K. At zero applied magnetic field, the critical current densities Jcs of the films on both sides of the wafer were measured to be above 2 × 106 A/cm2 at 77 K. The microwave surface resistance Rs of film was as low as 350 μΩ at 10 GHz and 77 K. In order to test the suitability of Tl-2212 thin films for passive microwave devices, 3-pole bandpass filters have been fabricated from double-sided Tl-2212 films on LaAlO3 substrates. 相似文献
149.
150.