Downhole working conditions of sucker rod pumping wells are automatically identified on a computer from the analysis of dynamometer cards. In this process, extraction of feature parameters and pattern classification a...Downhole working conditions of sucker rod pumping wells are automatically identified on a computer from the analysis of dynamometer cards. In this process, extraction of feature parameters and pattern classification are two key steps. The dynamometer card is firstly divided into four parts which include different production information according to the ＂four point method＂ used in actual oilfield production, and then the moment invariants for pattern recognition are extracted. An improved support vector machine （SVM） method is used for pattern classification whose error penalty parameter C and kernel function parameter g are optimally chosen by the particle swarm optimization （PSO） algorithm. The simulation results show the method proposed in this paper has good classification results.展开更多
The ROD baffle heat exchanger can slightly enhance the shell side heat transfer coefficient with the significant reduction of pressure, loss due to the shell side fluid flowing longitudinally through tube bundle, whic...The ROD baffle heat exchanger can slightly enhance the shell side heat transfer coefficient with the significant reduction of pressure, loss due to the shell side fluid flowing longitudinally through tube bundle, which leads to the reduction of the manufacture and running cost and in some cases to the dimensions reduction of the heat exchangers. Because of the complexities of fluid dynamics equations and the structure of heat exchangers, few theoretical researches have been accomplished to specify the shell side characteristics of the ROD baffle heat exchanger. A unit duct model in the shell side of the longitudinal flow type heat exchanger has been developed based on suitable simplification. A numerical analysis on shell side of the ROD baffle heat exchanger has been carried out at constant wall temperature to obtain the characteristics of heat transfer and pressure drop. The numerical results show that the ROD baffles placed vertically and horizontally in the unit duct continue to shear and comminute the streamline flow when the fluid crosses over the ROD-baffles, and change the fluid flow directions, and then the continuity and stability of the fluid axe destroyed. The effect of disturbing flow can promote fluid turbulent intensity and effectively enhance heat transfer. The numerical analyses can provide the theoretical bases for optimizing the structure of ROD baffle heat exchanger and improving its performance.展开更多
One novel metal-organic framework [Cu2（L）（μ3-OH）]n（1, H3L = [1,1＇：3＇,1＇＇-terphenyl]-4,4＇＇,5＇-tricarboxylic acid） has been synthesized and characterized by single-crystal powder X-ray diffraction, IR and...One novel metal-organic framework [Cu2（L）（μ3-OH）]n（1, H3L = [1,1＇：3＇,1＇＇-terphenyl]-4,4＇＇,5＇-tricarboxylic acid） has been synthesized and characterized by single-crystal powder X-ray diffraction, IR and thermogravimetric analyses. Complex 1 crystallizes in orthorhombic crystal system, space group Pbca with a = 21.573（19）, b = 5.404（5）, c = 33.78（3） ？, C21H（12）O7Cu2, Mr = 503.39, V = 3938（6） A^3, Z = 8, Dc = 1.698 g·cm^-3, μ = 2.202 mm^-1, F（000） = 2016, 1.531〈θ〈25.009°, λ（Mo Kα） = 0.71073 A, T = 293（2） K, the final R = 0.0448 and wR = 0.1002. The structure of complex 1 is a three-dimensional（3D） framework based on infinite rod-shaped secondary building units and can be simplified as kgd topology. The gas adsorption measurements for N2, CO2, H2O, CH3OH and CH3CH2OH have been done. Fortunately, the selective sorption of CO2 over N2 was found at 195 K.展开更多
A series of main chain liquid crystal aromatic copolyesters with X-shaped and rod-shaped mesogenic units were synthesized via solution condensation polymerizations of 4,4'-(alpha,omega-octanedioyloxy)-dibenzoyl di...A series of main chain liquid crystal aromatic copolyesters with X-shaped and rod-shaped mesogenic units were synthesized via solution condensation polymerizations of 4,4'-(alpha,omega-octanedioyloxy)-dibenzoyl dichlorides with 2,5-bis(p-octanoxy benzoyloxy)-hydroquinone and diphenol. All of the copolyesters showed thermotropic liquid crystalline behaviors through observations using DSC, polarized microscopy and X-ray diffraction. The melting point (T-m) and the isotropization temperature (T-i) change regularly with varying the content of diphenol unit in the copolymers.展开更多
随着电力系统对灵活性资源需求的增加,核电作为一种稳定、可控的清洁能源未来在电力系统中不可避免要承担调峰的任务。在调度需求下,主蒸汽阀门开度的频繁变化对一回路冷却剂平均温度等参数产生了一定程度的扰动,而反应堆冷却剂平均温...随着电力系统对灵活性资源需求的增加,核电作为一种稳定、可控的清洁能源未来在电力系统中不可避免要承担调峰的任务。在调度需求下,主蒸汽阀门开度的频繁变化对一回路冷却剂平均温度等参数产生了一定程度的扰动,而反应堆冷却剂平均温度控制系统中的功率失配通道难以满足快速控制的要求。为了提高堆机协调中反应堆调节的快速响应能力,降低主蒸汽阀门开度变化对一回路冷却剂平均温度等参数的扰动,依据大型压水堆(Pressurized Water Reactor,PWR)核电机组的模型,在传统的R棒控制系统的基础上引入以汽轮机负荷为输入信号的前馈环节。一方面,采用理论推导方法,在合理简化R棒控制系统的基础上,借助梅逊公式精确计算前馈环节传递函数;另一方面,采用粒子群算法,依托MATLAB与Simulink之间数据交互,直接对前馈环节传递函数中的待定参数进行寻优。最后,在80%工况下引入±5%、±10%和±20%的负荷阶跃,仿真结果表明:6种负荷阶跃工况下,理论推导的前馈环节让一回路冷却剂温度和主蒸汽压力调节时间缩短53.7%⁓89.6%,波动降22.8%⁓100%;粒子群优化算法计算的前馈环节使调节时间优化64.4%⁓95.3%,波动降23.4%⁓100%。由两种方法得出的前馈环节引入到R棒控制系统中均能有效大幅提升一回路平均温度与主蒸汽压力的调节速度,降低其波动性。所提出的理论计算方法与粒子群优化算法的结果相近,且具有计算成本低、操作简便的优势,在工程中更具应用价值。展开更多
基金support from the Key Project of the National Natural Science Foundation of China (61034005)Postgraduate Scientific Research and Innovation Projects of Basic Scientific Research Operating Expenses of Ministry of Education (N100604001)
文摘Downhole working conditions of sucker rod pumping wells are automatically identified on a computer from the analysis of dynamometer cards. In this process, extraction of feature parameters and pattern classification are two key steps. The dynamometer card is firstly divided into four parts which include different production information according to the ＂four point method＂ used in actual oilfield production, and then the moment invariants for pattern recognition are extracted. An improved support vector machine （SVM） method is used for pattern classification whose error penalty parameter C and kernel function parameter g are optimally chosen by the particle swarm optimization （PSO） algorithm. The simulation results show the method proposed in this paper has good classification results.
文摘The ROD baffle heat exchanger can slightly enhance the shell side heat transfer coefficient with the significant reduction of pressure, loss due to the shell side fluid flowing longitudinally through tube bundle, which leads to the reduction of the manufacture and running cost and in some cases to the dimensions reduction of the heat exchangers. Because of the complexities of fluid dynamics equations and the structure of heat exchangers, few theoretical researches have been accomplished to specify the shell side characteristics of the ROD baffle heat exchanger. A unit duct model in the shell side of the longitudinal flow type heat exchanger has been developed based on suitable simplification. A numerical analysis on shell side of the ROD baffle heat exchanger has been carried out at constant wall temperature to obtain the characteristics of heat transfer and pressure drop. The numerical results show that the ROD baffles placed vertically and horizontally in the unit duct continue to shear and comminute the streamline flow when the fluid crosses over the ROD-baffles, and change the fluid flow directions, and then the continuity and stability of the fluid axe destroyed. The effect of disturbing flow can promote fluid turbulent intensity and effectively enhance heat transfer. The numerical analyses can provide the theoretical bases for optimizing the structure of ROD baffle heat exchanger and improving its performance.
基金Supported by the Natural Science Foundation of Shandong Province(No.ZR2016BL01)the Talent Introduction Project of Dezhou University(No.320116)
文摘One novel metal-organic framework [Cu2（L）（μ3-OH）]n（1, H3L = [1,1＇：3＇,1＇＇-terphenyl]-4,4＇＇,5＇-tricarboxylic acid） has been synthesized and characterized by single-crystal powder X-ray diffraction, IR and thermogravimetric analyses. Complex 1 crystallizes in orthorhombic crystal system, space group Pbca with a = 21.573（19）, b = 5.404（5）, c = 33.78（3） ？, C21H（12）O7Cu2, Mr = 503.39, V = 3938（6） A^3, Z = 8, Dc = 1.698 g·cm^-3, μ = 2.202 mm^-1, F（000） = 2016, 1.531〈θ〈25.009°, λ（Mo Kα） = 0.71073 A, T = 293（2） K, the final R = 0.0448 and wR = 0.1002. The structure of complex 1 is a three-dimensional（3D） framework based on infinite rod-shaped secondary building units and can be simplified as kgd topology. The gas adsorption measurements for N2, CO2, H2O, CH3OH and CH3CH2OH have been done. Fortunately, the selective sorption of CO2 over N2 was found at 195 K.
基金The work was supported by the National Natural Science Foundation of China.
文摘A series of main chain liquid crystal aromatic copolyesters with X-shaped and rod-shaped mesogenic units were synthesized via solution condensation polymerizations of 4,4'-(alpha,omega-octanedioyloxy)-dibenzoyl dichlorides with 2,5-bis(p-octanoxy benzoyloxy)-hydroquinone and diphenol. All of the copolyesters showed thermotropic liquid crystalline behaviors through observations using DSC, polarized microscopy and X-ray diffraction. The melting point (T-m) and the isotropization temperature (T-i) change regularly with varying the content of diphenol unit in the copolymers.
文摘随着电力系统对灵活性资源需求的增加,核电作为一种稳定、可控的清洁能源未来在电力系统中不可避免要承担调峰的任务。在调度需求下,主蒸汽阀门开度的频繁变化对一回路冷却剂平均温度等参数产生了一定程度的扰动,而反应堆冷却剂平均温度控制系统中的功率失配通道难以满足快速控制的要求。为了提高堆机协调中反应堆调节的快速响应能力,降低主蒸汽阀门开度变化对一回路冷却剂平均温度等参数的扰动,依据大型压水堆(Pressurized Water Reactor,PWR)核电机组的模型,在传统的R棒控制系统的基础上引入以汽轮机负荷为输入信号的前馈环节。一方面,采用理论推导方法,在合理简化R棒控制系统的基础上,借助梅逊公式精确计算前馈环节传递函数;另一方面,采用粒子群算法,依托MATLAB与Simulink之间数据交互,直接对前馈环节传递函数中的待定参数进行寻优。最后,在80%工况下引入±5%、±10%和±20%的负荷阶跃,仿真结果表明:6种负荷阶跃工况下,理论推导的前馈环节让一回路冷却剂温度和主蒸汽压力调节时间缩短53.7%⁓89.6%,波动降22.8%⁓100%;粒子群优化算法计算的前馈环节使调节时间优化64.4%⁓95.3%,波动降23.4%⁓100%。由两种方法得出的前馈环节引入到R棒控制系统中均能有效大幅提升一回路平均温度与主蒸汽压力的调节速度,降低其波动性。所提出的理论计算方法与粒子群优化算法的结果相近,且具有计算成本低、操作简便的优势,在工程中更具应用价值。
