Based on the state-of-the-art studies of solar-soil source heat pump compound system, operation patterns of solar-soil compound system were analyzed, particularly the advantages of parallel operation pattern. It is fo...Based on the state-of-the-art studies of solar-soil source heat pump compound system, operation patterns of solar-soil compound system were analyzed, particularly the advantages of parallel operation pattern. It is found that parallel operation pattern is better for solar-soil compound system. Furthermore, the heat balance issue of solar-soil compound system was emphatically analyzed from four aspects, which were annual analysis of heating and cooling load, the heat exchange of ground heat exchanger, capacity determination of solar-assisted heat sottrce and heat balance calculation of solar-soil compound system. Moreover, annual rate of heat balance in a solar-soil source heat pump compound system was calculated with a case study. It is shown that the annual heat unbalance ratio is 19%, which is less than 20%. As a result, the practical solar-soil compound system can basically maintain the heat balance of soil.展开更多
To weaken the nonlinear coupling influence among the variables in the speed and tension system of reversible cold strip mill, a compound control(CC) strategy based on invariance principle was proposed. Firstly, invari...To weaken the nonlinear coupling influence among the variables in the speed and tension system of reversible cold strip mill, a compound control(CC) strategy based on invariance principle was proposed. Firstly, invariance principle was used to realize static decoupling between the speed and tension of reversible cold strip mill. Then, considering the influence caused by the time variation of steel coil radius and rotational inertia of the left and right coilers, as well as the uncertainties, a CC strategy that is composed of extended state observer(ESO) and global sliding mode control(GSMC) with backstepping adaptive was proposed,which further realized dynamic decoupling and coordination control for the speed and tension system. Theoretical analysis shows that the resulting closed-loop system is global bounded stable. Finally, the simulation was carried out on the speed and tension system of a 1422 mm reversible cold strip mill by using the actual data, and through the comparison of the other control strategies, validity of the proposed CC strategy was shown by the results.展开更多
This paper focuses on the adaptive detection of range and Doppler dual-spread targets in non-homogeneous and nonGaussian sea clutter.The sea clutter from two polarimetric channels is modeled as a compound-Gaussian mod...This paper focuses on the adaptive detection of range and Doppler dual-spread targets in non-homogeneous and nonGaussian sea clutter.The sea clutter from two polarimetric channels is modeled as a compound-Gaussian model with different parameters,and the target is modeled as a subspace rangespread target model.The persymmetric structure is used to model the clutter covariance matrix,in order to reduce the reliance on secondary data of the designed detectors.Three adaptive polarimetric persymmetric detectors are designed based on the generalized likelihood ratio test(GLRT),Rao test,and Wald test.All the proposed detectors have constant falsealarm rate property with respect to the clutter texture,the speckle covariance matrix.Experimental results on simulated and measured data show that three adaptive detectors outperform the competitors in different clutter environments,and the proposed GLRT detector has the best detection performance under different parameters.展开更多
A solar-water compound source heat pump for radiant floor heating (SWHP-RFH) experimental system was introduced and analyzed. The SWHP-RFH system mainly consists of 11.44 m2 vacuum tube solar collector,1 000 L water t...A solar-water compound source heat pump for radiant floor heating (SWHP-RFH) experimental system was introduced and analyzed. The SWHP-RFH system mainly consists of 11.44 m2 vacuum tube solar collector,1 000 L water tank assisted 3 kW electrical heater,a water source heat pump,the radiant floor heating system with cross-linked polyethylene (PE-X) of diameter 20 mm,temperature controller and solar testing system. The SWHP-RFH system was tested from December to February during the heating season in Beijing,China under different operation situations. The test parameters include the outdoor air temperature,solar radiation intensity,indoor air temperature,radiation floor average surface temperature,average surface temperature of the building envelope,the inlet and outlet temperatures of solar collector,the temperature of water tank,the heat medium temperatures of heat pump condenser side and evaporator side,and the power consumption includes the water source heat pump system,the solar source heat pump system,the auxiliary heater and the radiant floor heating systems etc. The experimental results were used to calculate the collector efficiency,heat pump dynamic coefficient of performance (COP),total energy consumption and seasonal heating performance during the heating season. The results indicate that the performance of the compound source heat pump system is better than that of the air source heat pump system. Furthermore,some methods are suggested to improve the thermal performance of each component and the whole SWHP-RFH system.展开更多
A simulation calculation model for the solubility of insoluble compound MmAa in complex system was established.According to coordination equilibrium principle,relevant dissociation reaction,complexation reaction,self-...A simulation calculation model for the solubility of insoluble compound MmAa in complex system was established.According to coordination equilibrium principle,relevant dissociation reaction,complexation reaction,self-complexation reaction and protonation reaction during insoluble compound dissolving were considered and then the mass balance equations about solubility calculation were obtained.In the case analysis,the solubility of silver chloride in ammonia system was obtained by simulation calculation,and curved surface charts of thermodynamic equilibrium about the total concentration of silver ions,pH and concentration of ammonia ions were drawn correspondingly.The results show that under the conditions of room temperature and 6 mol/L ammonia concentration,the calculated solubility value of silver chloride(34 g/L) is close to the actual value(31 g/L),demonstrating that this model is suitable for solubility calculation of insoluble compound MmAa in the complex system.展开更多
Here we present a simple yet effective gas chromatography-mass spectrometry(GC-MS)identification approach for the detection of heteroatom-containing compounds(HACCs)in petroleum fractions.The MS/AMDIS(Automated Mass S...Here we present a simple yet effective gas chromatography-mass spectrometry(GC-MS)identification approach for the detection of heteroatom-containing compounds(HACCs)in petroleum fractions.The MS/AMDIS(Automated Mass Spectral Deconvolution and Identification System)program was used to identify parts per million(ppm)HACC concentrations in petroleum fractions in place of traditional techniques(extraction and standard injection).Polycyclic aromatic sulfur heterocycles(S-PAHs)were used as model compounds to confirm the validity of the AMDIS identifiers,which were compared with extracted results using the off-line X-calibur software.AMDIS was able to identify ppm concentrations of S-PAHs in oil condensate.There was good agreement between experimental and AMDIS identification results for S-PAHs in oil condensate.AMDIS was also used to detect nitrogen-containing compounds(NCCs)and alkylphenols in oil condensate.Our results confirmed the presence of 2-methylbenzothiazole,carbazole,and 2,4-ditertbutyl phenol.In a crude oil sample,AMDIS identification of m/z=191 biomarkers wa s consistent with empirical results.Therefore,AMDIS can help to reduce the number of experimental steps in identification protocols.展开更多
Aimed at the problem of classification of non-hydrocarbons of crude oil, the theoretical standpoint that the polarity of a compound depends on the whole structure and composition of molecule instead of a kind of heter...Aimed at the problem of classification of non-hydrocarbons of crude oil, the theoretical standpoint that the polarity of a compound depends on the whole structure and composition of molecule instead of a kind of heteroatom or its functional group was presented. A method was established for the systematically structural identification of nitric compounds in crude oil. The pre-fractionation of a crude oil sample into 7 fractions was performed by di- adsorption column chromatography with neutral aluminum oxide and silica gel. Subsequently, the individual components were obtained by using capillary column gas chromatography, and the types of compounds were detected by a mass spectrometer. In combination with a chemometric resolution, the compounds of fraction were further identified. This method can relieve the difficulty of classical analysis in identifying those species with very low contents or without being completely separated. The structures of 168 nitric compounds in a crude oil sample were determined by this method.展开更多
Nitrogen-rich heterocyclic energetic compounds(NRHECs)and their salts have witnessed widespread synthesis in recent years.The substantial energy-density content within these compounds can lead to potentially dangerous...Nitrogen-rich heterocyclic energetic compounds(NRHECs)and their salts have witnessed widespread synthesis in recent years.The substantial energy-density content within these compounds can lead to potentially dangerous explosive reactions when subjected to external stimuli such as electrical discharge.Therefore,developing a reliable model for predicting their electrostatic discharge sensitivity(ESD)becomes imperative.This study proposes a novel and straightforward model based on the presence of specific groups(-NH_(2) or-NH-,-N=N^(+)-O^(-)and-NNO_(2),-ONO_(2) or-NO_(2))under certain conditions to assess the ESD of NRHECs and their salts,employing interpretable structural parameters.Utilizing a comprehensive dataset comprising 54 ESD measurements of NRHECs and their salts,divided into 49/5 training/test sets,the model achieves promising results.The Root Mean Square Error(RMSE),Mean Absolute Error(MAE),and Maximum Error for the training set are reported as 0.16 J,0.12 J,and 0.5 J,respectively.Notably,the ratios RMSE(training)/RMSE(test),MAE(training)/MAE(test),and Max Error(training)/Max Error(test)are all greater than 1.0,indicating the robust predictive capabilities of the model.The presented model demonstrates its efficacy in providing a reliable assessment of ESD for the targeted NRHECs and their salts,without the need for intricate computer codes or expert involvement.展开更多
In this study,the morphology and ultrastructure of the compound eye of L.lewisii were investigated using scanning electron microscopy(SEM),transmission electron microscopy(TEM),microcomputed tomography(μCT),and 3D re...In this study,the morphology and ultrastructure of the compound eye of L.lewisii were investigated using scanning electron microscopy(SEM),transmission electron microscopy(TEM),microcomputed tomography(μCT),and 3D reconstruction.The compound eye of L.lewisii was of the apposition type,with an average of 121.88±7.64 ommatidia in males and 119.00±4.71 ommatidia in females.Each ommatidium was composed of a biconvex cornea,an acone consisting of four cone cells,eight retinular cells along with the rhabdom,two primary pigment cells,and numerous secondary pigment cells.The open type of rhabdom in L.lewisii consists of six peripheral rhabdomeres contributed by the six peripheral retinular cells(R1~R6)and two vertically attached central rhabdomeres contributed by R7 and R8 respectively.The orientation of microvilli suggested a weak sensitivity to polarized light perception.展开更多
基金Project(50838009) supported by the National Natural Science Foundation of ChinaProject(2010DFA72740-05) supported by the International Science & Technology Cooperation Program of China
文摘Based on the state-of-the-art studies of solar-soil source heat pump compound system, operation patterns of solar-soil compound system were analyzed, particularly the advantages of parallel operation pattern. It is found that parallel operation pattern is better for solar-soil compound system. Furthermore, the heat balance issue of solar-soil compound system was emphatically analyzed from four aspects, which were annual analysis of heating and cooling load, the heat exchange of ground heat exchanger, capacity determination of solar-assisted heat sottrce and heat balance calculation of solar-soil compound system. Moreover, annual rate of heat balance in a solar-soil source heat pump compound system was calculated with a case study. It is shown that the annual heat unbalance ratio is 19%, which is less than 20%. As a result, the practical solar-soil compound system can basically maintain the heat balance of soil.
基金Project(61074099)supported by the National Natural Science Foundation of ChinaProject(LJRC013)supported by Cultivation Program for Leading Talent of Innovation Team in Colleges and Universities of Hebei Province,ChinaProject(B705)supported by Doctor Foundation of Yanshan University,China
文摘To weaken the nonlinear coupling influence among the variables in the speed and tension system of reversible cold strip mill, a compound control(CC) strategy based on invariance principle was proposed. Firstly, invariance principle was used to realize static decoupling between the speed and tension of reversible cold strip mill. Then, considering the influence caused by the time variation of steel coil radius and rotational inertia of the left and right coilers, as well as the uncertainties, a CC strategy that is composed of extended state observer(ESO) and global sliding mode control(GSMC) with backstepping adaptive was proposed,which further realized dynamic decoupling and coordination control for the speed and tension system. Theoretical analysis shows that the resulting closed-loop system is global bounded stable. Finally, the simulation was carried out on the speed and tension system of a 1422 mm reversible cold strip mill by using the actual data, and through the comparison of the other control strategies, validity of the proposed CC strategy was shown by the results.
基金supported by the National Natural Science Foundation of China(62371382,62071346)the Science,Technology&Innovation Project of Xiong’an New Area(2022XAGG0181)the Special Funds for Creative Research(2022C61540)。
文摘This paper focuses on the adaptive detection of range and Doppler dual-spread targets in non-homogeneous and nonGaussian sea clutter.The sea clutter from two polarimetric channels is modeled as a compound-Gaussian model with different parameters,and the target is modeled as a subspace rangespread target model.The persymmetric structure is used to model the clutter covariance matrix,in order to reduce the reliance on secondary data of the designed detectors.Three adaptive polarimetric persymmetric detectors are designed based on the generalized likelihood ratio test(GLRT),Rao test,and Wald test.All the proposed detectors have constant falsealarm rate property with respect to the clutter texture,the speckle covariance matrix.Experimental results on simulated and measured data show that three adaptive detectors outperform the competitors in different clutter environments,and the proposed GLRT detector has the best detection performance under different parameters.
基金Project(2006BAJ03A06) supported by National Science and Technology Pillar Program During 11th Five-Year Plan
文摘A solar-water compound source heat pump for radiant floor heating (SWHP-RFH) experimental system was introduced and analyzed. The SWHP-RFH system mainly consists of 11.44 m2 vacuum tube solar collector,1 000 L water tank assisted 3 kW electrical heater,a water source heat pump,the radiant floor heating system with cross-linked polyethylene (PE-X) of diameter 20 mm,temperature controller and solar testing system. The SWHP-RFH system was tested from December to February during the heating season in Beijing,China under different operation situations. The test parameters include the outdoor air temperature,solar radiation intensity,indoor air temperature,radiation floor average surface temperature,average surface temperature of the building envelope,the inlet and outlet temperatures of solar collector,the temperature of water tank,the heat medium temperatures of heat pump condenser side and evaporator side,and the power consumption includes the water source heat pump system,the solar source heat pump system,the auxiliary heater and the radiant floor heating systems etc. The experimental results were used to calculate the collector efficiency,heat pump dynamic coefficient of performance (COP),total energy consumption and seasonal heating performance during the heating season. The results indicate that the performance of the compound source heat pump system is better than that of the air source heat pump system. Furthermore,some methods are suggested to improve the thermal performance of each component and the whole SWHP-RFH system.
基金Project(2007CB613604) supported by the National Basic Research Program of China
文摘A simulation calculation model for the solubility of insoluble compound MmAa in complex system was established.According to coordination equilibrium principle,relevant dissociation reaction,complexation reaction,self-complexation reaction and protonation reaction during insoluble compound dissolving were considered and then the mass balance equations about solubility calculation were obtained.In the case analysis,the solubility of silver chloride in ammonia system was obtained by simulation calculation,and curved surface charts of thermodynamic equilibrium about the total concentration of silver ions,pH and concentration of ammonia ions were drawn correspondingly.The results show that under the conditions of room temperature and 6 mol/L ammonia concentration,the calculated solubility value of silver chloride(34 g/L) is close to the actual value(31 g/L),demonstrating that this model is suitable for solubility calculation of insoluble compound MmAa in the complex system.
文摘Here we present a simple yet effective gas chromatography-mass spectrometry(GC-MS)identification approach for the detection of heteroatom-containing compounds(HACCs)in petroleum fractions.The MS/AMDIS(Automated Mass Spectral Deconvolution and Identification System)program was used to identify parts per million(ppm)HACC concentrations in petroleum fractions in place of traditional techniques(extraction and standard injection).Polycyclic aromatic sulfur heterocycles(S-PAHs)were used as model compounds to confirm the validity of the AMDIS identifiers,which were compared with extracted results using the off-line X-calibur software.AMDIS was able to identify ppm concentrations of S-PAHs in oil condensate.There was good agreement between experimental and AMDIS identification results for S-PAHs in oil condensate.AMDIS was also used to detect nitrogen-containing compounds(NCCs)and alkylphenols in oil condensate.Our results confirmed the presence of 2-methylbenzothiazole,carbazole,and 2,4-ditertbutyl phenol.In a crude oil sample,AMDIS identification of m/z=191 biomarkers wa s consistent with empirical results.Therefore,AMDIS can help to reduce the number of experimental steps in identification protocols.
文摘Aimed at the problem of classification of non-hydrocarbons of crude oil, the theoretical standpoint that the polarity of a compound depends on the whole structure and composition of molecule instead of a kind of heteroatom or its functional group was presented. A method was established for the systematically structural identification of nitric compounds in crude oil. The pre-fractionation of a crude oil sample into 7 fractions was performed by di- adsorption column chromatography with neutral aluminum oxide and silica gel. Subsequently, the individual components were obtained by using capillary column gas chromatography, and the types of compounds were detected by a mass spectrometer. In combination with a chemometric resolution, the compounds of fraction were further identified. This method can relieve the difficulty of classical analysis in identifying those species with very low contents or without being completely separated. The structures of 168 nitric compounds in a crude oil sample were determined by this method.
文摘Nitrogen-rich heterocyclic energetic compounds(NRHECs)and their salts have witnessed widespread synthesis in recent years.The substantial energy-density content within these compounds can lead to potentially dangerous explosive reactions when subjected to external stimuli such as electrical discharge.Therefore,developing a reliable model for predicting their electrostatic discharge sensitivity(ESD)becomes imperative.This study proposes a novel and straightforward model based on the presence of specific groups(-NH_(2) or-NH-,-N=N^(+)-O^(-)and-NNO_(2),-ONO_(2) or-NO_(2))under certain conditions to assess the ESD of NRHECs and their salts,employing interpretable structural parameters.Utilizing a comprehensive dataset comprising 54 ESD measurements of NRHECs and their salts,divided into 49/5 training/test sets,the model achieves promising results.The Root Mean Square Error(RMSE),Mean Absolute Error(MAE),and Maximum Error for the training set are reported as 0.16 J,0.12 J,and 0.5 J,respectively.Notably,the ratios RMSE(training)/RMSE(test),MAE(training)/MAE(test),and Max Error(training)/Max Error(test)are all greater than 1.0,indicating the robust predictive capabilities of the model.The presented model demonstrates its efficacy in providing a reliable assessment of ESD for the targeted NRHECs and their salts,without the need for intricate computer codes or expert involvement.
文摘In this study,the morphology and ultrastructure of the compound eye of L.lewisii were investigated using scanning electron microscopy(SEM),transmission electron microscopy(TEM),microcomputed tomography(μCT),and 3D reconstruction.The compound eye of L.lewisii was of the apposition type,with an average of 121.88±7.64 ommatidia in males and 119.00±4.71 ommatidia in females.Each ommatidium was composed of a biconvex cornea,an acone consisting of four cone cells,eight retinular cells along with the rhabdom,two primary pigment cells,and numerous secondary pigment cells.The open type of rhabdom in L.lewisii consists of six peripheral rhabdomeres contributed by the six peripheral retinular cells(R1~R6)and two vertically attached central rhabdomeres contributed by R7 and R8 respectively.The orientation of microvilli suggested a weak sensitivity to polarized light perception.
