In this paper,a novel NH_(3)/CO_(2)ejector-cascade refrigeration system with regenerator is proposed,which can recycle the waste heat at the outlet of the compressor.After establishing the mathematical model of the sy...In this paper,a novel NH_(3)/CO_(2)ejector-cascade refrigeration system with regenerator is proposed,which can recycle the waste heat at the outlet of the compressor.After establishing the mathematical model of the system,the theoretical energy and exergy analysis are carried out and compared with the conventional cascade refrigeration system.It is concluded that compared with the conventional cascade refrigeration system,the novel ejector-cascade refrigeration system with regenerator has the advantages of less power consumption of the compressor,less component exergy destruction,high system performance,and is more suitable for working at a lower temperature.Under the working conditions studied in this paper,compared with the conventional cascade refrigeration system,the COP of the novel ejector-cascade refrigeration system with regenerator is increased by9.58%;the exergy efficiency is increased by 9.50%,and the optimal evaporation temperature is about-45℃.展开更多
The rapid development of information technology has fueled an ever-increasing demand for ultrafast and ultralow-en-ergy-consumption computing.Existing computing instruments are pre-dominantly electronic processors,whi...The rapid development of information technology has fueled an ever-increasing demand for ultrafast and ultralow-en-ergy-consumption computing.Existing computing instruments are pre-dominantly electronic processors,which use elec-trons as information carriers and possess von Neumann architecture featured by physical separation of storage and pro-cessing.The scaling of computing speed is limited not only by data transfer between memory and processing units,but also by RC delay associated with integrated circuits.Moreover,excessive heating due to Ohmic losses is becoming a severe bottleneck for both speed and power consumption scaling.Using photons as information carriers is a promising alternative.Owing to the weak third-order optical nonlinearity of conventional materials,building integrated photonic com-puting chips under traditional von Neumann architecture has been a challenge.Here,we report a new all-optical comput-ing framework to realize ultrafast and ultralow-energy-consumption all-optical computing based on convolutional neural networks.The device is constructed from cascaded silicon Y-shaped waveguides with side-coupled silicon waveguide segments which we termed“weight modulators”to enable complete phase and amplitude control in each waveguide branch.The generic device concept can be used for equation solving,multifunctional logic operations as well as many other mathematical operations.Multiple computing functions including transcendental equation solvers,multifarious logic gate operators,and half-adders were experimentally demonstrated to validate the all-optical computing performances.The time-of-flight of light through the network structure corresponds to an ultrafast computing time of the order of several picoseconds with an ultralow energy consumption of dozens of femtojoules per bit.Our approach can be further expan-ded to fulfill other complex computing tasks based on non-von Neumann architectures and thus paves a new way for on-chip all-optical computing.展开更多
The occurrence of cardiovascular events is one of the important causes of death and disability in the nation.The ischemia and hypoxia of myocardial cells caused by coronary atherosclerosis,intravascular stenosis or my...The occurrence of cardiovascular events is one of the important causes of death and disability in the nation.The ischemia and hypoxia of myocardial cells caused by coronary atherosclerosis,intravascular stenosis or myocardial infarction leads to cell damage,necrosis and apoptosis,leading to Myocardial fibrosis affects cardiac function and the quality of life of patients.Reducing myocardial cell apoptosis,inhibiting myocardial fibrosis and promoting myocardial cell regeneration are of great significance for maintaining the normal shape and function of the heart.With the progress of research,scientists have discovered that the Hippo pathway plays an important role in the repair and regeneration of myocardial cells.This article reviews the regulatory effects and mechanisms of the various factors in the Hioop signaling pathway in the repair and regeneration of cardiomyocytes.展开更多
Spinal cord injury（SCI）is one of the most common causes of paralysis worldwide because the loss of neurons and axons causes permanent neurological deficits which could have influences on quality of life of patients,...Spinal cord injury（SCI）is one of the most common causes of paralysis worldwide because the loss of neurons and axons causes permanent neurological deficits which could have influences on quality of life of patients,their family,and society.The complex pathophysiology of SCI,especially the secondary injury cascade,blocks complete recovery after SCI（Dumont et al.,2001）.展开更多
Based on solving the couple mode equation numerically, the characterization of the signal power on the gate power was analyzed. And the relationship of the tolerance of the grating period and the bulk temperature on t...Based on solving the couple mode equation numerically, the characterization of the signal power on the gate power was analyzed. And the relationship of the tolerance of the grating period and the bulk temperature on the interaction length was analyzed.展开更多
We propose a novel optical signal regeneration system based on wavelength converters by use of cross gain modulation in cascaded semiconductor optical amplifiers. The nonlinearity in optical input/output characteristi...We propose a novel optical signal regeneration system based on wavelength converters by use of cross gain modulation in cascaded semiconductor optical amplifiers. The nonlinearity in optical input/output characteristics and eye opening using NRZ signal were archived.展开更多
基金supported by National Natural Science Foundation of China(No.51976095)the Taishan Scholar Program of Shandong(No.tsqn201812073)。
文摘In this paper,a novel NH_(3)/CO_(2)ejector-cascade refrigeration system with regenerator is proposed,which can recycle the waste heat at the outlet of the compressor.After establishing the mathematical model of the system,the theoretical energy and exergy analysis are carried out and compared with the conventional cascade refrigeration system.It is concluded that compared with the conventional cascade refrigeration system,the novel ejector-cascade refrigeration system with regenerator has the advantages of less power consumption of the compressor,less component exergy destruction,high system performance,and is more suitable for working at a lower temperature.Under the working conditions studied in this paper,compared with the conventional cascade refrigeration system,the COP of the novel ejector-cascade refrigeration system with regenerator is increased by9.58%;the exergy efficiency is increased by 9.50%,and the optimal evaporation temperature is about-45℃.
基金financial supports from the National Key Research and Development Program of China(2018YFB2200403)National Natural Sci-ence Foundation of China(NSFC)(61775003,11734001,91950204,11527901,11604378,91850117).
文摘The rapid development of information technology has fueled an ever-increasing demand for ultrafast and ultralow-en-ergy-consumption computing.Existing computing instruments are pre-dominantly electronic processors,which use elec-trons as information carriers and possess von Neumann architecture featured by physical separation of storage and pro-cessing.The scaling of computing speed is limited not only by data transfer between memory and processing units,but also by RC delay associated with integrated circuits.Moreover,excessive heating due to Ohmic losses is becoming a severe bottleneck for both speed and power consumption scaling.Using photons as information carriers is a promising alternative.Owing to the weak third-order optical nonlinearity of conventional materials,building integrated photonic com-puting chips under traditional von Neumann architecture has been a challenge.Here,we report a new all-optical comput-ing framework to realize ultrafast and ultralow-energy-consumption all-optical computing based on convolutional neural networks.The device is constructed from cascaded silicon Y-shaped waveguides with side-coupled silicon waveguide segments which we termed“weight modulators”to enable complete phase and amplitude control in each waveguide branch.The generic device concept can be used for equation solving,multifunctional logic operations as well as many other mathematical operations.Multiple computing functions including transcendental equation solvers,multifarious logic gate operators,and half-adders were experimentally demonstrated to validate the all-optical computing performances.The time-of-flight of light through the network structure corresponds to an ultrafast computing time of the order of several picoseconds with an ultralow energy consumption of dozens of femtojoules per bit.Our approach can be further expan-ded to fulfill other complex computing tasks based on non-von Neumann architectures and thus paves a new way for on-chip all-optical computing.
基金National Natural Science Foundation of China Regional Fund Project(No.81960861)National Natural Science Foundation of China Regional Fund Project(No.81460712)Guangxi Key Scientific RESEARCH and Development Program Project Subject(No.Guike AB19110006)。
文摘The occurrence of cardiovascular events is one of the important causes of death and disability in the nation.The ischemia and hypoxia of myocardial cells caused by coronary atherosclerosis,intravascular stenosis or myocardial infarction leads to cell damage,necrosis and apoptosis,leading to Myocardial fibrosis affects cardiac function and the quality of life of patients.Reducing myocardial cell apoptosis,inhibiting myocardial fibrosis and promoting myocardial cell regeneration are of great significance for maintaining the normal shape and function of the heart.With the progress of research,scientists have discovered that the Hippo pathway plays an important role in the repair and regeneration of myocardial cells.This article reviews the regulatory effects and mechanisms of the various factors in the Hioop signaling pathway in the repair and regeneration of cardiomyocytes.
文摘Spinal cord injury（SCI）is one of the most common causes of paralysis worldwide because the loss of neurons and axons causes permanent neurological deficits which could have influences on quality of life of patients,their family,and society.The complex pathophysiology of SCI,especially the secondary injury cascade,blocks complete recovery after SCI（Dumont et al.,2001）.
文摘Based on solving the couple mode equation numerically, the characterization of the signal power on the gate power was analyzed. And the relationship of the tolerance of the grating period and the bulk temperature on the interaction length was analyzed.
文摘We propose a novel optical signal regeneration system based on wavelength converters by use of cross gain modulation in cascaded semiconductor optical amplifiers. The nonlinearity in optical input/output characteristics and eye opening using NRZ signal were archived.
