The rotating packed bed （RPB） with split packing is a novel gas-liquid contactor, which intensifies the mass transfer processes controlled by gas-side resistance. To assess its efficacy, the mass transfer characteri...The rotating packed bed （RPB） with split packing is a novel gas-liquid contactor, which intensifies the mass transfer processes controlled by gas-side resistance. To assess its efficacy, the mass transfer characteristics with adjacent rings in counter-rotation and co-rotation modes in a split packing RPB were studied experimentally. The physical absorption system NH3-H2O was used for characterizing the gas volumetric mass transfer coeffi- cient （kyae） and the effective inteffacial area （ae） was determined by chemical absorption in the CO2-NaOH sys- tem. The variation in kyae and ae with the operating conditions is also investigated. The experimental results indicated that kyae and ae for counter-rotation of the adjacent packing rings in the split packing RPB were higher than those for co-rotation, and both counter-rotation and co-rotation of the split packing RPB were superior over conventional RPBs under the similar ooerating conditions.展开更多
Dynamic performance is important to the controlling and monitoring of the organic Rankine cycle(ORC) system so to avoid the occurrence of unwanted conditions. A small scale waste heat recovery system with organic Rank...Dynamic performance is important to the controlling and monitoring of the organic Rankine cycle(ORC) system so to avoid the occurrence of unwanted conditions. A small scale waste heat recovery system with organic Rankine cycle was constructed and the dynamic behavior was presented. In the dynamic test, the pump was stopped and then started. In addition, there was a step change of the flue gas volume flow rate and the converter frequency of multistage pump, respectively. The results indicate that the working fluid flow rate has the shortest response time, followed by the expander inlet pressure and the expander inlet temperature.The operation frequency of pump is a key parameter for the ORC system. Due to a step change of pump frequency(39.49-35.24 Hz),the expander efficiency and thermal efficiency drop by 16% and 21% within 2 min, respectively. Besides, the saturated mixture can lead to an increase of the expander rotation speed.展开更多
The uplink achievable rate of massive multiple-input-multiple-output(MIMO) systems, where the low-resolution analog-to-digital converters(ADCs) are assumed to equip at the base station(BS), is investigated in this pap...The uplink achievable rate of massive multiple-input-multiple-output(MIMO) systems, where the low-resolution analog-to-digital converters(ADCs) are assumed to equip at the base station(BS), is investigated in this paper. We assume that only imperfect channel station information is known at the BS. Then a new MMSE receiver is designed by taking not only the Gaussian noise, but also the channel estimation error and quantizer noise into account. By using the Stieltjes transform of random matrix, we further derive a tight asymptotic equivalent for the uplink achievable rate with proposed MMSE receiver. We present a detailed analysis for the number of BS antennas through the expression of the achievable rates and validate the results using numerical simulations. It is also shown that we can compensate the performance loss due to the low-resolution quantization by increasing the number of antennas at the BS.展开更多
The aim of the study was to characterize humus system of natural and artificial products. Humus systems from leonardite, lignite biotransformed with Trichoderma sp. （Plantagra）, plant materials after pyrolisis （cha...The aim of the study was to characterize humus system of natural and artificial products. Humus systems from leonardite, lignite biotransformed with Trichoderma sp. （Plantagra）, plant materials after pyrolisis （charcoal） and composts are compared. Humus systems are characterized by Kononova-Belchikova＇s method, and heavy metals content was measured by atomic absorption spectroscopy （AAS）. Humic acids from the International Humic Substances Society （IHSS） collection are the standards for humus substances quality of compared products. Data obtained for leonardite indicate that the studied substances from factory, Izmir, Turkey contain humic acids over 94%. Compared to the standard, heavy metals content in these materials demonstrate high amounts. Organic carbon content in the composts is very low compared to the leonardite materials and IHSS collection, where the heavy metals content is lower. Biotransformed lignite is characterized with lower content of organic carbon, but humic acids are with high degree of humification. Results obtained show that the fourth studied humus systems may be used in agriculture on base of the high humic acids content. It is recommended to measure heavy metals content before applying the materials in agriculture.展开更多
The heat storage solar Stirling generator referred in this paper is a power conversion unit integrating sunlight receiver, regenerative chamber, Stirling engine and generator, which increases a heat storage function r...The heat storage solar Stirling generator referred in this paper is a power conversion unit integrating sunlight receiver, regenerative chamber, Stirling engine and generator, which increases a heat storage function relative to similar power conversion units. This power conversion unit adopts invention patents authorized in China in recent years to apply to dish solar Stirling thermal power system, and it will be sure to become a principal part of future energy internet and the optimal technical route of CSP （concentrating solar power）. The trough system rests on that Stirling generator substitutes the steam turbine to desalt seawater by remaining heat during power generation. Accordingly, the tower system will be rejected.展开更多
A finite-time tracking control scheme is proposed in this paper based on the terminal sliding mode principle for motor servo systems with unknown nonlinear dead-zone inputs.By using the differential mean value theorem...A finite-time tracking control scheme is proposed in this paper based on the terminal sliding mode principle for motor servo systems with unknown nonlinear dead-zone inputs.By using the differential mean value theorem,the dead-zone is represented as a time-varying system and thus the inverse compensation approach is avoided.Then,an indirect terminal sliding mode control(ITSMC)is developed to guarantee the finite-time convergence of the tracking error and to overcome the singularity problem in the traditional terminal sliding mode control.In the proposed controller design,the unknown nonlinearity of the system is approximated by a simple sigmoid neural network,and the approximation error is diminished by employing a robust term.Comparative experiments on a turntable servo system are conducted to show the superior performance of the proposed method.展开更多
基金the National Natural Science Foundation of China(21376229,21206153)
文摘The rotating packed bed （RPB） with split packing is a novel gas-liquid contactor, which intensifies the mass transfer processes controlled by gas-side resistance. To assess its efficacy, the mass transfer characteristics with adjacent rings in counter-rotation and co-rotation modes in a split packing RPB were studied experimentally. The physical absorption system NH3-H2O was used for characterizing the gas volumetric mass transfer coeffi- cient （kyae） and the effective inteffacial area （ae） was determined by chemical absorption in the CO2-NaOH sys- tem. The variation in kyae and ae with the operating conditions is also investigated. The experimental results indicated that kyae and ae for counter-rotation of the adjacent packing rings in the split packing RPB were higher than those for co-rotation, and both counter-rotation and co-rotation of the split packing RPB were superior over conventional RPBs under the similar ooerating conditions.
基金Project(2009Gk2009)supported by the Science and Technology Department Funds of Hunan Province,ChinaProject(12C0379)supported by the Scientific Research Fund of Hunan Province,ChinaProject(13QDZ04)supported by the Scientific Research Foundation for Doctors of Xiang Tan University,China
文摘Dynamic performance is important to the controlling and monitoring of the organic Rankine cycle(ORC) system so to avoid the occurrence of unwanted conditions. A small scale waste heat recovery system with organic Rankine cycle was constructed and the dynamic behavior was presented. In the dynamic test, the pump was stopped and then started. In addition, there was a step change of the flue gas volume flow rate and the converter frequency of multistage pump, respectively. The results indicate that the working fluid flow rate has the shortest response time, followed by the expander inlet pressure and the expander inlet temperature.The operation frequency of pump is a key parameter for the ORC system. Due to a step change of pump frequency(39.49-35.24 Hz),the expander efficiency and thermal efficiency drop by 16% and 21% within 2 min, respectively. Besides, the saturated mixture can lead to an increase of the expander rotation speed.
基金supported by the Beijing Natural Science Foundation under Grant No. L172030the Beijing Municipal Natural Science Foundation under Grant No. 4174102+2 种基金NSFC Project under Grants No. 61471027the National Natural Science Foundation of China under Grant No. 61701017 and Grant No. 61601018the Open Research Fund through the National Mobile Communications Research Laboratory, Southeast University, under Grant No. 2017D01
文摘The uplink achievable rate of massive multiple-input-multiple-output(MIMO) systems, where the low-resolution analog-to-digital converters(ADCs) are assumed to equip at the base station(BS), is investigated in this paper. We assume that only imperfect channel station information is known at the BS. Then a new MMSE receiver is designed by taking not only the Gaussian noise, but also the channel estimation error and quantizer noise into account. By using the Stieltjes transform of random matrix, we further derive a tight asymptotic equivalent for the uplink achievable rate with proposed MMSE receiver. We present a detailed analysis for the number of BS antennas through the expression of the achievable rates and validate the results using numerical simulations. It is also shown that we can compensate the performance loss due to the low-resolution quantization by increasing the number of antennas at the BS.
文摘The aim of the study was to characterize humus system of natural and artificial products. Humus systems from leonardite, lignite biotransformed with Trichoderma sp. （Plantagra）, plant materials after pyrolisis （charcoal） and composts are compared. Humus systems are characterized by Kononova-Belchikova＇s method, and heavy metals content was measured by atomic absorption spectroscopy （AAS）. Humic acids from the International Humic Substances Society （IHSS） collection are the standards for humus substances quality of compared products. Data obtained for leonardite indicate that the studied substances from factory, Izmir, Turkey contain humic acids over 94%. Compared to the standard, heavy metals content in these materials demonstrate high amounts. Organic carbon content in the composts is very low compared to the leonardite materials and IHSS collection, where the heavy metals content is lower. Biotransformed lignite is characterized with lower content of organic carbon, but humic acids are with high degree of humification. Results obtained show that the fourth studied humus systems may be used in agriculture on base of the high humic acids content. It is recommended to measure heavy metals content before applying the materials in agriculture.
文摘The heat storage solar Stirling generator referred in this paper is a power conversion unit integrating sunlight receiver, regenerative chamber, Stirling engine and generator, which increases a heat storage function relative to similar power conversion units. This power conversion unit adopts invention patents authorized in China in recent years to apply to dish solar Stirling thermal power system, and it will be sure to become a principal part of future energy internet and the optimal technical route of CSP （concentrating solar power）. The trough system rests on that Stirling generator substitutes the steam turbine to desalt seawater by remaining heat during power generation. Accordingly, the tower system will be rejected.
基金supported by the Scientific Research Foundation of the Education Department of Zhejiang Province,China under Grant No.Y201329260the Natural Science Foundation of Zhejiang Province,China under Grant No.LZ12E07003the National Natural Science Foundation of China under Grant No.51207139
文摘A finite-time tracking control scheme is proposed in this paper based on the terminal sliding mode principle for motor servo systems with unknown nonlinear dead-zone inputs.By using the differential mean value theorem,the dead-zone is represented as a time-varying system and thus the inverse compensation approach is avoided.Then,an indirect terminal sliding mode control(ITSMC)is developed to guarantee the finite-time convergence of the tracking error and to overcome the singularity problem in the traditional terminal sliding mode control.In the proposed controller design,the unknown nonlinearity of the system is approximated by a simple sigmoid neural network,and the approximation error is diminished by employing a robust term.Comparative experiments on a turntable servo system are conducted to show the superior performance of the proposed method.
