To extend the service life of the upper checker bricks in the regenerator of glass furnaces with petroleum coke as fuel,the corrosion resistance of magnesia-chrome and alumina-chrome bricks with the similar apparent p...To extend the service life of the upper checker bricks in the regenerator of glass furnaces with petroleum coke as fuel,the corrosion resistance of magnesia-chrome and alumina-chrome bricks with the similar apparent porosity was systematically researched.The results show that the Cr2O3 content and the microstructure present significant effects on the corrosion resistance.The molten corrosion reagent forms silicate and vanadate phases with low melting points between MgO crystals in magnesia-chrome bricks,and the volume strain generated by the melting and solidification process leads to the cracking and spalling of refractories,which intensifies the corrosion process.The encapsulation of alumina particles by alumina-chrome solid solutions in alumina-chrome bricks avoids contact with the low melting point liquid phases and improves the corrosion resistance of refractories.展开更多
In this article, researches on improvement of 1RX regenerator used in cleaning processes of cotton ginning enterprises were carried out. The effect of changing the parameters of the new working body—rubber-plate drum...In this article, researches on improvement of 1RX regenerator used in cleaning processes of cotton ginning enterprises were carried out. The effect of changing the parameters of the new working body—rubber-plate drum and machine inlet on the efficiency of cotton separation was studied in the research, and the maximum level of efficiency of separation was determined. In this paper work, the main factors affecting the efficient operation of the regenerator were identified, their value limits were determined, and research was conducted using the mathematical planning method. As a result, effective operation of the improved 1RX cotton regenerator was observed at the value of the given factors, that is, the separation efficiency was 99.5%, the cleaning efficiency was higher than 88.7%, and the amount of seed cotton in the waste was reduced lower than 2.5%.展开更多
The quantitative investigation of parameters in the renegerator is essential for the optimization of thermoacoustic devices, while the majority of the previous research only considered parameters of the working field,...The quantitative investigation of parameters in the renegerator is essential for the optimization of thermoacoustic devices, while the majority of the previous research only considered parameters of the working field, working gas and the hydraulic radius. Based on the linear thermoacoustic theory, this paper extracts a normalized parameter for low-amplitude conditions, which is called the regenerator operation factor. By extracting the regenerator operation factor and relative hydraulic radius, the influence of frequency on the efficiency can be controlled and offset. It can be found that thermoacoustic devices with different frequencies can perform the same efficiency by adjusting the radius in proportion to the axial length.Finally, this paper synthetically optimizes the dimension of the thermoacoustic regenerator by taking the regenerator operation factor, relative hydraulic radius and acoustic field parameter as variables. Conclusions in this paper are of great significance for explaining the best working conditions of engines and directing the miniaturization and optimal design of thermoacoustic devices.展开更多
The special subject 'research on life prediction technology of important in-service pressure' mainly analyzes the failure mechanism of large-sized important and criticalin-service pressure vessels under the ac...The special subject 'research on life prediction technology of important in-service pressure' mainly analyzes the failure mechanism of large-sized important and criticalin-service pressure vessels under the action of working medium and investigates safety assessmentand life prediction technology with a view to enhance the operation reliability of in-servicepressure vessels in China. Based on a series of accident investigation and test & measuringresearch, the cause of cracking of catalytic regenerator is analyzed and the in-line non-destructiveexamination method and failure prevention measures for the cracking of catalytic regenerator areproposed.展开更多
A parameter perturbation for the unsteady-state heat-transfer characteristics of honeycomb regenerator is presented. It is limited to the cases where the storage matrix has a small wall thickness so that no temperatur...A parameter perturbation for the unsteady-state heat-transfer characteristics of honeycomb regenerator is presented. It is limited to the cases where the storage matrix has a small wall thickness so that no temperature variation in the matrix perpendicular to the flow direction is considered. Starting from a two-phase transient thermal model for the gas and storage matrix, an approximate solution for regenerator heat transfer process is derived using the multiple-scale method for the limiting case where the longitudinal heat conduction of solid matrix is far less than the convective heat transfer between the gas and the solid. The regenerator temperature profiles are expressed as Taylor series of the coefficient of solid heat conduction item in the model. The analytical validity is shown by comparing the perturbation solution with the experiment and the numerical solution. The results show that it is possible for the perturbation to improve the effectiveness and economics of thermal research on regenerators.展开更多
In mammalian species, including humans, spinal cord in- jury (SCI) leads to permanent disability. A major cause of disability after SCI is the failure of axotomized descending axons to regenerate across the trauma z...In mammalian species, including humans, spinal cord in- jury (SCI) leads to permanent disability. A major cause of disability after SCI is the failure of axotomized descending axons to regenerate across the trauma zone and to reconnect to they appropriate targets distal to the site of injury. Cur- renfly, major research efforts are devoted to find new ways of promoting the regrowth of damaged descending axons. However, activation of axonal regrowth will depend on the survival of the axotomized descending brain neurons.展开更多
A new method was proposed to directly measure the effective resistance and distinguish the porous frequency in the regenerator of the microminiature thermoacoustic refrigerator. Measured results were compared with the...A new method was proposed to directly measure the effective resistance and distinguish the porous frequency in the regenerator of the microminiature thermoacoustic refrigerator. Measured results were compared with the flux gain factor and transmission loss of the real system. The results show that the agreement between the range of the porous frequency and frequency of the system is good, the method can be used to predict the porous frequency of the regenerator in production.展开更多
A renovation project of miniaturization and high efficiency is provided for the hot blast stove .The experimental data tested feasibility of the new-type swirl flow hot blast stove. The normal and hot state experiment...A renovation project of miniaturization and high efficiency is provided for the hot blast stove .The experimental data tested feasibility of the new-type swirl flow hot blast stove. The normal and hot state experiments have been done through changing the angle of gas entering into the regenerator. Factors influencing pressure drop have been studied and analyzed. The experimental results can be formulated in the form of the Ergun equation. The regression equation is obtained. And two modified coefficients are offered to the regenerator pressure drop of the new-type swirl flow hot blast stove.展开更多
An active thermo-acoustic network model of regenerator which is a key component to accomplish the con-version between thermal-and acoustic power in thermo-acoustic system has been established in this paper. The experi...An active thermo-acoustic network model of regenerator which is a key component to accomplish the con-version between thermal-and acoustic power in thermo-acoustic system has been established in this paper. The experiment was carried out to quantify the network. A method called least square is employed in order to identify the H matrix describing the system. The results obtained here show that the active thermo-acoustic network can reliably depict the characteristics of a thermo-acoustic system.展开更多
Real time phase regeneration is necessary for degraded phase modulation format optical communication systems. A regenerator based on the discrimitive gain effect of a semiconductor optical amplifier was proposed in re...Real time phase regeneration is necessary for degraded phase modulation format optical communication systems. A regenerator based on the discrimitive gain effect of a semiconductor optical amplifier was proposed in recent years. In this paper, for this type of regenerator, its optimal working condition is found by solving the dynamic equations which describe the variance of the optical field and carrier density in the semiconductor optical amplifier by the finite difference method. The results show that the optimal improvement of signal Q factor can reach more than 2.2 dB.展开更多
In order to control the heat saturation time, the temperature field of the regenerators of high temperature air combustion (HTAC) technology after reheating furnace was studied. A one-dimensional unsteady mathematic...In order to control the heat saturation time, the temperature field of the regenerators of high temperature air combustion (HTAC) technology after reheating furnace was studied. A one-dimensional unsteady mathematical model was established and discretized through finite difference method. The relationship between the heat saturation time and some factors was determined through the calculation of a program developed by language C. The heat saturation time decreases with the increase of heat convection coefficient, however, the increase of heat capacity, density and radius of regenerator all increase the heat saturation time approximately linearly.展开更多
During long-term use,the clay checker bricks for regenerators of coke ovens on gas side react with the impurities containing Fe and K20,causing foaming,softening and deformation,which is not only related with the impu...During long-term use,the clay checker bricks for regenerators of coke ovens on gas side react with the impurities containing Fe and K20,causing foaming,softening and deformation,which is not only related with the impurity content and properties of the clay checker bricks,but also related with the type and the composition of the dust in the gas.After long term use,the clay checker bricks of coke ovens on air side have relative lower impurities containing Fe and K20.The inferior clay checker bricks,with high impurity content and high porosity,are easy to pulverize and deteriorate due to the oxidationreduction reaction with the iron oxide and the gas.The gas quality shall be concerned for long service life of the coke oven regenerators.展开更多
An approach for the simulation and optimization of continuous catalyst-regenerative process of reforming is proposed in this paper.Compared to traditional method such as finite difference method,the orthogonal colloca...An approach for the simulation and optimization of continuous catalyst-regenerative process of reforming is proposed in this paper.Compared to traditional method such as finite difference method,the orthogonal collocation method is less time-consuming and more accurate,which can meet the requirement of real-time optimization(RTO).In this paper,the equation-oriented method combined with the orthogonal collocation method and the finite difference method is adopted to build the RTO model for catalytic reforming regenerator.The orthogonal collocation method was adopted to discretize the differential equations and sequential quadratic programming(SQP)algorithm was used to solve the algebraic equations.The rate constants,active energy and reaction order were estimated,with the sum of relative errors between actual value and simulated value serving as optimization objective function.The model can quickly predict the fields of component concentration,temperature and pressure inside the regenerator under different conditions,as well as the real-time optimized conditions for industrial reforming regenerator.展开更多
Regenerator checkerwork for glass melting furnaces should have high resistance against thermal stress and chemical attack,high mechanical stability,high efficiency to recover the heat from waste gas and low tendency f...Regenerator checkerwork for glass melting furnaces should have high resistance against thermal stress and chemical attack,high mechanical stability,high efficiency to recover the heat from waste gas and low tendency for clogging.This article reviews the innovation of the regenerator checkerwork from the past decades.The state of the art for optimised material choice and optimised checker shapes will be reported.展开更多
In order to provide a novel and more effective alternative to the commonly used relay protection testing device that outputs only the sinusoidal testing signals, the concept of fault waveform regenerator is proposed i...In order to provide a novel and more effective alternative to the commonly used relay protection testing device that outputs only the sinusoidal testing signals, the concept of fault waveform regenerator is proposed in this paper, together with its hardware structure and software flow chart. Fault waveform regenerator mainly depends on its power amplifiers (PAs) to regenerate the fault waveforms recorded by digital fault recorder (DFR). To counteract the PA’s inherent nonlinear distortions, a digital closed-loop modification technique that is different from the predistortion technique is conceived. And the experimental results verify the effectiveness of the fault waveform regenerator based on the digital closed-loop modification technique.展开更多
The catalyst regeneration process running under the partial oxidation mode in traditional fluid catalytic cracking(FCC)units needs a carbon monoxide(CO)boiler to burn the flue gas,resulting in a large volume of CO_(2)...The catalyst regeneration process running under the partial oxidation mode in traditional fluid catalytic cracking(FCC)units needs a carbon monoxide(CO)boiler to burn the flue gas,resulting in a large volume of CO_(2) emissions.In this study,the performance of a set of industrial serial-type FCC regenerators and the changes in flue gas composition were analyzed by establishing a model of the regenerators and the flue gas energy recovery section.Considering the value of utilizing CO,based on the simulation,this paper proposes two schemes for maximizing CO content in the flue gas of regenerators.The two sets of optimal process operating parameters were obtained using a genetic algorithm.Compared with the original process,the CO contents of flue gas in the two optimized processes increased to 6.6%and 12.5%,CO_(2) emissions were reduced by 48.4%and 96.7%,and the costs of CO production were 0.57$/m^(3) and 0.84$/m^(3),respectively.展开更多
Phase and amplitude regeneration are necessary for degraded differential phase-shift keying communication sys- tems. This paper proposes a regenerator based on semiconductor optical amplifier for differential phase-sh...Phase and amplitude regeneration are necessary for degraded differential phase-shift keying communication sys- tems. This paper proposes a regenerator based on semiconductor optical amplifier for differential phase-shift keying signals. The key regeneration mechanism is theoretically analysed. The effectiveness of semiconductor optical amplifier based regenerator is demonstrated by comparing the bit error rate and eye diagrams before and after regeneration for 40-Cbit/s differential phase-shift keying 1080-km transmission systems. The results show that regeneration effects are very well. Bit error rate is tess than 10-12 with the regenerator.展开更多
Regenerators play a vital role in enhancing the overall performance of Stirling engines.Hence,this paper performed an energy and exergy analysis to elucidate the significance of regenerator characteristics concerning ...Regenerators play a vital role in enhancing the overall performance of Stirling engines.Hence,this paper performed an energy and exergy analysis to elucidate the significance of regenerator characteristics concerning system performance,contributing to the optimal regenerator’s design and selection.The relationship between regenerator structure,regenerator exergy destruction,and output power,thermal efficiency,and exergy efficiency for Stirling engines was established by integrating the thermal model of Stirling engines with a mathematical model of regenerators.In contrast to cross-flow and parallel-flow regenerators,a novel concept of inclined-flow regenerators,featuring a matrix surface inclined in the direction of gas flow,was developed to achieve higher and more balanced engine output power and energy utilization efficiency.A comprehensive investigation was conducted into the effects of matrix structure types and regenerator geometries on the performance of both regenerators and engines.The results reveal that,following structural optimization,Stirling engines equipped with the inclined-flow regenerator demonstrate a substantial 16.6%,38.3%,and 37.2%increase in power output,thermal efficiency,and exergy efficiency,respectively,compared to those equipped with cross-flow regenerators.In contrast,when compared to engines fitted with parallel-flow regenerators,they experience a 13.5%reduction in power output but achieve remarkable enhancements of 45.4%and 36.7%in thermal and exergy efficiency,respectively.This study introduces new insights into selecting regenerator structures for enhancing the output performance of Stirling engines.展开更多
Injuries caused by trauma and neurodegenerative diseases can damage the peripheral nervous system and cause functional deficits.Unlike in the central nervous system,damaged axons in peripheral nerves can be induced to...Injuries caused by trauma and neurodegenerative diseases can damage the peripheral nervous system and cause functional deficits.Unlike in the central nervous system,damaged axons in peripheral nerves can be induced to regenerate in response to intrinsic cues after reprogramming or in a growth-promoting microenvironment created by Schwann cells.However,axon regeneration and repair do not automatically result in the restoration of function,which is the ultimate therapeutic goal but also a major clinical challenge.Transforming growth factor(TGF)is a multifunctional cytokine that regulates various biological processes including tissue repair,embryo development,and cell growth and differentiation.There is accumulating evidence that TGF-βfamily proteins participate in peripheral nerve repair through various factors and signaling pathways by regulating the growth and transformation of Schwann cells;recruiting specific immune cells;controlling the permeability of the blood-nerve barrier,thereby stimulating axon growth;and inhibiting remyelination of regenerated axons.TGF-βhas been applied to the treatment of peripheral nerve injury in animal models.In this context,we review the functions of TGF-βin peripheral nerve regeneration and potential clinical applications.展开更多
Macrophages play an important role in peripheral nerve regeneration,but the specific mechanism of regeneration is still unclear.Our preliminary findings indicated that neutrophil peptide 1 is an innate immune peptide ...Macrophages play an important role in peripheral nerve regeneration,but the specific mechanism of regeneration is still unclear.Our preliminary findings indicated that neutrophil peptide 1 is an innate immune peptide closely involved in peripheral nerve regeneration.However,the mechanism by which neutrophil peptide 1 enhances nerve regeneration remains unclear.This study was designed to investigate the relationship between neutrophil peptide 1 and macrophages in vivo and in vitro in peripheral nerve crush injury.The functions of RAW 264.7 cells we re elucidated by Cell Counting Kit-8 assay,flow cytometry,migration assays,phagocytosis assays,immunohistochemistry and enzyme-linked immunosorbent assay.Axonal debris phagocytosis was observed using the CUBIC(Clear,Unobstructed Brain/Body Imaging Cocktails and Computational analysis)optical clearing technique during Wallerian degeneration.Macrophage inflammatory factor expression in different polarization states was detected using a protein chip.The results showed that neutrophil peptide 1 promoted the prolife ration,migration and phagocytosis of macrophages,and CD206 expression on the surfa ce of macrophages,indicating M2 polarization.The axonal debris clearance rate during Wallerian degeneration was enhanced after neutrophil peptide 1 intervention.Neutrophil peptide 1 also downregulated inflammatory factors interleukin-1α,-6,-12,and tumor necrosis factor-αin invo and in vitro.Thus,the results suggest that neutrophil peptide 1 activates macrophages and accelerates Wallerian degeneration,which may be one mechanism by which neutrophil peptide 1 enhances peripheral nerve regeneration.展开更多
基金support from the National Natural Science Foundation of China(U20A20239)the Key Research and Development Project of Hubei Province,China(2022BAA032).
文摘To extend the service life of the upper checker bricks in the regenerator of glass furnaces with petroleum coke as fuel,the corrosion resistance of magnesia-chrome and alumina-chrome bricks with the similar apparent porosity was systematically researched.The results show that the Cr2O3 content and the microstructure present significant effects on the corrosion resistance.The molten corrosion reagent forms silicate and vanadate phases with low melting points between MgO crystals in magnesia-chrome bricks,and the volume strain generated by the melting and solidification process leads to the cracking and spalling of refractories,which intensifies the corrosion process.The encapsulation of alumina particles by alumina-chrome solid solutions in alumina-chrome bricks avoids contact with the low melting point liquid phases and improves the corrosion resistance of refractories.
文摘In this article, researches on improvement of 1RX regenerator used in cleaning processes of cotton ginning enterprises were carried out. The effect of changing the parameters of the new working body—rubber-plate drum and machine inlet on the efficiency of cotton separation was studied in the research, and the maximum level of efficiency of separation was determined. In this paper work, the main factors affecting the efficient operation of the regenerator were identified, their value limits were determined, and research was conducted using the mathematical planning method. As a result, effective operation of the improved 1RX cotton regenerator was observed at the value of the given factors, that is, the separation efficiency was 99.5%, the cleaning efficiency was higher than 88.7%, and the amount of seed cotton in the waste was reduced lower than 2.5%.
基金Project supported by the National Natural Science Foundation of China (Grant No. 51925605)。
文摘The quantitative investigation of parameters in the renegerator is essential for the optimization of thermoacoustic devices, while the majority of the previous research only considered parameters of the working field, working gas and the hydraulic radius. Based on the linear thermoacoustic theory, this paper extracts a normalized parameter for low-amplitude conditions, which is called the regenerator operation factor. By extracting the regenerator operation factor and relative hydraulic radius, the influence of frequency on the efficiency can be controlled and offset. It can be found that thermoacoustic devices with different frequencies can perform the same efficiency by adjusting the radius in proportion to the axial length.Finally, this paper synthetically optimizes the dimension of the thermoacoustic regenerator by taking the regenerator operation factor, relative hydraulic radius and acoustic field parameter as variables. Conclusions in this paper are of great significance for explaining the best working conditions of engines and directing the miniaturization and optimal design of thermoacoustic devices.
基金important scientech problemtackling subject foundation under the state 9th 5-year plan(no.96-918-02-04).
文摘The special subject 'research on life prediction technology of important in-service pressure' mainly analyzes the failure mechanism of large-sized important and criticalin-service pressure vessels under the action of working medium and investigates safety assessmentand life prediction technology with a view to enhance the operation reliability of in-servicepressure vessels in China. Based on a series of accident investigation and test & measuringresearch, the cause of cracking of catalytic regenerator is analyzed and the in-line non-destructiveexamination method and failure prevention measures for the cracking of catalytic regenerator areproposed.
基金Item Sponsored by High Technology Research Development Program of China(2005AA001020,2001AA514013)
文摘A parameter perturbation for the unsteady-state heat-transfer characteristics of honeycomb regenerator is presented. It is limited to the cases where the storage matrix has a small wall thickness so that no temperature variation in the matrix perpendicular to the flow direction is considered. Starting from a two-phase transient thermal model for the gas and storage matrix, an approximate solution for regenerator heat transfer process is derived using the multiple-scale method for the limiting case where the longitudinal heat conduction of solid matrix is far less than the convective heat transfer between the gas and the solid. The regenerator temperature profiles are expressed as Taylor series of the coefficient of solid heat conduction item in the model. The analytical validity is shown by comparing the perturbation solution with the experiment and the numerical solution. The results show that it is possible for the perturbation to improve the effectiveness and economics of thermal research on regenerators.
文摘In mammalian species, including humans, spinal cord in- jury (SCI) leads to permanent disability. A major cause of disability after SCI is the failure of axotomized descending axons to regenerate across the trauma zone and to reconnect to they appropriate targets distal to the site of injury. Cur- renfly, major research efforts are devoted to find new ways of promoting the regrowth of damaged descending axons. However, activation of axonal regrowth will depend on the survival of the axotomized descending brain neurons.
基金Project supported by the Postdoctoral Science Foundation of Central South University
文摘A new method was proposed to directly measure the effective resistance and distinguish the porous frequency in the regenerator of the microminiature thermoacoustic refrigerator. Measured results were compared with the flux gain factor and transmission loss of the real system. The results show that the agreement between the range of the porous frequency and frequency of the system is good, the method can be used to predict the porous frequency of the regenerator in production.
文摘A renovation project of miniaturization and high efficiency is provided for the hot blast stove .The experimental data tested feasibility of the new-type swirl flow hot blast stove. The normal and hot state experiments have been done through changing the angle of gas entering into the regenerator. Factors influencing pressure drop have been studied and analyzed. The experimental results can be formulated in the form of the Ergun equation. The regression equation is obtained. And two modified coefficients are offered to the regenerator pressure drop of the new-type swirl flow hot blast stove.
文摘An active thermo-acoustic network model of regenerator which is a key component to accomplish the con-version between thermal-and acoustic power in thermo-acoustic system has been established in this paper. The experiment was carried out to quantify the network. A method called least square is employed in order to identify the H matrix describing the system. The results obtained here show that the active thermo-acoustic network can reliably depict the characteristics of a thermo-acoustic system.
基金Project supported by the Scientific Fund for Chinese Universities (Grant No. BUPT 2011RC009)
文摘Real time phase regeneration is necessary for degraded phase modulation format optical communication systems. A regenerator based on the discrimitive gain effect of a semiconductor optical amplifier was proposed in recent years. In this paper, for this type of regenerator, its optimal working condition is found by solving the dynamic equations which describe the variance of the optical field and carrier density in the semiconductor optical amplifier by the finite difference method. The results show that the optimal improvement of signal Q factor can reach more than 2.2 dB.
文摘In order to control the heat saturation time, the temperature field of the regenerators of high temperature air combustion (HTAC) technology after reheating furnace was studied. A one-dimensional unsteady mathematical model was established and discretized through finite difference method. The relationship between the heat saturation time and some factors was determined through the calculation of a program developed by language C. The heat saturation time decreases with the increase of heat convection coefficient, however, the increase of heat capacity, density and radius of regenerator all increase the heat saturation time approximately linearly.
文摘During long-term use,the clay checker bricks for regenerators of coke ovens on gas side react with the impurities containing Fe and K20,causing foaming,softening and deformation,which is not only related with the impurity content and properties of the clay checker bricks,but also related with the type and the composition of the dust in the gas.After long term use,the clay checker bricks of coke ovens on air side have relative lower impurities containing Fe and K20.The inferior clay checker bricks,with high impurity content and high porosity,are easy to pulverize and deteriorate due to the oxidationreduction reaction with the iron oxide and the gas.The gas quality shall be concerned for long service life of the coke oven regenerators.
基金This work was supported by the Science and Technology Development Project of SINOPEC,China(No.319026).
文摘An approach for the simulation and optimization of continuous catalyst-regenerative process of reforming is proposed in this paper.Compared to traditional method such as finite difference method,the orthogonal collocation method is less time-consuming and more accurate,which can meet the requirement of real-time optimization(RTO).In this paper,the equation-oriented method combined with the orthogonal collocation method and the finite difference method is adopted to build the RTO model for catalytic reforming regenerator.The orthogonal collocation method was adopted to discretize the differential equations and sequential quadratic programming(SQP)algorithm was used to solve the algebraic equations.The rate constants,active energy and reaction order were estimated,with the sum of relative errors between actual value and simulated value serving as optimization objective function.The model can quickly predict the fields of component concentration,temperature and pressure inside the regenerator under different conditions,as well as the real-time optimized conditions for industrial reforming regenerator.
文摘Regenerator checkerwork for glass melting furnaces should have high resistance against thermal stress and chemical attack,high mechanical stability,high efficiency to recover the heat from waste gas and low tendency for clogging.This article reviews the innovation of the regenerator checkerwork from the past decades.The state of the art for optimised material choice and optimised checker shapes will be reported.
文摘In order to provide a novel and more effective alternative to the commonly used relay protection testing device that outputs only the sinusoidal testing signals, the concept of fault waveform regenerator is proposed in this paper, together with its hardware structure and software flow chart. Fault waveform regenerator mainly depends on its power amplifiers (PAs) to regenerate the fault waveforms recorded by digital fault recorder (DFR). To counteract the PA’s inherent nonlinear distortions, a digital closed-loop modification technique that is different from the predistortion technique is conceived. And the experimental results verify the effectiveness of the fault waveform regenerator based on the digital closed-loop modification technique.
文摘The catalyst regeneration process running under the partial oxidation mode in traditional fluid catalytic cracking(FCC)units needs a carbon monoxide(CO)boiler to burn the flue gas,resulting in a large volume of CO_(2) emissions.In this study,the performance of a set of industrial serial-type FCC regenerators and the changes in flue gas composition were analyzed by establishing a model of the regenerators and the flue gas energy recovery section.Considering the value of utilizing CO,based on the simulation,this paper proposes two schemes for maximizing CO content in the flue gas of regenerators.The two sets of optimal process operating parameters were obtained using a genetic algorithm.Compared with the original process,the CO contents of flue gas in the two optimized processes increased to 6.6%and 12.5%,CO_(2) emissions were reduced by 48.4%and 96.7%,and the costs of CO production were 0.57$/m^(3) and 0.84$/m^(3),respectively.
基金supported by the Scientific Fund for Chinese Universities (Grant No. BUPT 2009RC0413)the National "863" High Technology Projects (Grant No. 2009AA01Z224)
文摘Phase and amplitude regeneration are necessary for degraded differential phase-shift keying communication sys- tems. This paper proposes a regenerator based on semiconductor optical amplifier for differential phase-shift keying signals. The key regeneration mechanism is theoretically analysed. The effectiveness of semiconductor optical amplifier based regenerator is demonstrated by comparing the bit error rate and eye diagrams before and after regeneration for 40-Cbit/s differential phase-shift keying 1080-km transmission systems. The results show that regeneration effects are very well. Bit error rate is tess than 10-12 with the regenerator.
基金supported by the National Natural Science Foundation of China(Grant No.51736004).
文摘Regenerators play a vital role in enhancing the overall performance of Stirling engines.Hence,this paper performed an energy and exergy analysis to elucidate the significance of regenerator characteristics concerning system performance,contributing to the optimal regenerator’s design and selection.The relationship between regenerator structure,regenerator exergy destruction,and output power,thermal efficiency,and exergy efficiency for Stirling engines was established by integrating the thermal model of Stirling engines with a mathematical model of regenerators.In contrast to cross-flow and parallel-flow regenerators,a novel concept of inclined-flow regenerators,featuring a matrix surface inclined in the direction of gas flow,was developed to achieve higher and more balanced engine output power and energy utilization efficiency.A comprehensive investigation was conducted into the effects of matrix structure types and regenerator geometries on the performance of both regenerators and engines.The results reveal that,following structural optimization,Stirling engines equipped with the inclined-flow regenerator demonstrate a substantial 16.6%,38.3%,and 37.2%increase in power output,thermal efficiency,and exergy efficiency,respectively,compared to those equipped with cross-flow regenerators.In contrast,when compared to engines fitted with parallel-flow regenerators,they experience a 13.5%reduction in power output but achieve remarkable enhancements of 45.4%and 36.7%in thermal and exergy efficiency,respectively.This study introduces new insights into selecting regenerator structures for enhancing the output performance of Stirling engines.
基金supported by the National Natural Science Foundation of China,Nos.31971277 and 31950410551(both to DY)。
文摘Injuries caused by trauma and neurodegenerative diseases can damage the peripheral nervous system and cause functional deficits.Unlike in the central nervous system,damaged axons in peripheral nerves can be induced to regenerate in response to intrinsic cues after reprogramming or in a growth-promoting microenvironment created by Schwann cells.However,axon regeneration and repair do not automatically result in the restoration of function,which is the ultimate therapeutic goal but also a major clinical challenge.Transforming growth factor(TGF)is a multifunctional cytokine that regulates various biological processes including tissue repair,embryo development,and cell growth and differentiation.There is accumulating evidence that TGF-βfamily proteins participate in peripheral nerve repair through various factors and signaling pathways by regulating the growth and transformation of Schwann cells;recruiting specific immune cells;controlling the permeability of the blood-nerve barrier,thereby stimulating axon growth;and inhibiting remyelination of regenerated axons.TGF-βhas been applied to the treatment of peripheral nerve injury in animal models.In this context,we review the functions of TGF-βin peripheral nerve regeneration and potential clinical applications.
基金supported by the National Natural Science Foundation of China,No.32371048(to YK)the Peking University People’s Hospital Research and Development Funds,No.RDX2021-01(to YK)the Natural Science Foundation of Beijing,No.7222198(to NH)。
文摘Macrophages play an important role in peripheral nerve regeneration,but the specific mechanism of regeneration is still unclear.Our preliminary findings indicated that neutrophil peptide 1 is an innate immune peptide closely involved in peripheral nerve regeneration.However,the mechanism by which neutrophil peptide 1 enhances nerve regeneration remains unclear.This study was designed to investigate the relationship between neutrophil peptide 1 and macrophages in vivo and in vitro in peripheral nerve crush injury.The functions of RAW 264.7 cells we re elucidated by Cell Counting Kit-8 assay,flow cytometry,migration assays,phagocytosis assays,immunohistochemistry and enzyme-linked immunosorbent assay.Axonal debris phagocytosis was observed using the CUBIC(Clear,Unobstructed Brain/Body Imaging Cocktails and Computational analysis)optical clearing technique during Wallerian degeneration.Macrophage inflammatory factor expression in different polarization states was detected using a protein chip.The results showed that neutrophil peptide 1 promoted the prolife ration,migration and phagocytosis of macrophages,and CD206 expression on the surfa ce of macrophages,indicating M2 polarization.The axonal debris clearance rate during Wallerian degeneration was enhanced after neutrophil peptide 1 intervention.Neutrophil peptide 1 also downregulated inflammatory factors interleukin-1α,-6,-12,and tumor necrosis factor-αin invo and in vitro.Thus,the results suggest that neutrophil peptide 1 activates macrophages and accelerates Wallerian degeneration,which may be one mechanism by which neutrophil peptide 1 enhances peripheral nerve regeneration.