Based on a new perspective of industry chain and selecting monthly data from February2006to December2015,this paper chooses eight Chinese industrial sectors to construct a SVAR model reflecting internal relationships ...Based on a new perspective of industry chain and selecting monthly data from February2006to December2015,this paper chooses eight Chinese industrial sectors to construct a SVAR model reflecting internal relationships among metal chains,analyzes the direct effects and indirect effects of international metal prices on output of various links in metal chains,then it investigates the main transmission path of international metal price shocks through decomposing the inflation pressure sources in metal chains.The results show that international metal price shocks not only affect industrial output in a direct way,but also indirectly affect the growth of output through the increased pressure on industrial inflation and then triggering a tightening of monetary policy implementation.Affected by factors such as the lack of market demand and the price transmission mechanism blocking,the direct effects of international metal price shocks mainly impact the upstream and midstream industry,while the downstream industry is mainly affected by indirect effects;in addition,the international metal price shocks have spillover effects on the industrial inflation,and transmit along the industry chain from upstream to downstream,and their strength weakens in sequence.展开更多
In order to minimize the energy consumption in the discovery of the routing path, this paper introduces a novel concept of effective transmission (ET) that ensures each forwarding node is not only farther from the s...In order to minimize the energy consumption in the discovery of the routing path, this paper introduces a novel concept of effective transmission (ET) that ensures each forwarding node is not only farther from the source node, but also nearer to the destination node with respect to its sender, An energ-aware routing protocol based on ET is proposed. It enables the energy consumption for each hop to be the least for the transmission. The simulation results show the routing protocol is effective in the performance of energy consumption comparing with some other routing protocols.展开更多
BACKGROUND: Some studies suggest that the long-term potentiation (LTP) of synaptic transmission may be the basis for the neural synaptic plasticity of hippocampus, but can be evoked by various factors including ele...BACKGROUND: Some studies suggest that the long-term potentiation (LTP) of synaptic transmission may be the basis for the neural synaptic plasticity of hippocampus, but can be evoked by various factors including electroacupuncture. OBJECTIVE: To observe the effect of electroacupuncture on the activities of basic synaptic transmission in dentate gyrus of hippocampus and the changes of high frequency stimulation (HFS) induced activity of synaptic transmission in cerebral ischemic injured rats. DESIGN: A randomized control trial.SETTING: Shenzhen Hospital of Traditional Chinese Medicine affiliated to Guangzhou University of Traditional Chinese Medicine. MATERIALS: Sixty healthy male Wistar rats, weighing 150-250 g, were provided by the Experimental Animal Center of Guangzhou University of Traditional Chinese Medicine. The experiment began after adaptation of environment for 1 week under standard experimental environment. The main experimental instruments included the programming electrical acupuncture apparatus (PCEA, product of the Institute of Acupuncture and Meridians, Anhui College of Traditional Chinese Medicine) and multichannel physiologic recorder (RM-86, Nihon Konden). METHODS: The experiment was carried out in Guangzhou University of Traditional Chinese Medicine between July 2003 and July 2004. ①Embedding of brain electrodes: In reference of the Pellegrino's rat brain atlas, the bipolar electrode stimulator was embedded into the perforant path (PP) anterior to the entorhinal area with location coordinates of AP 7.5 mm, L 4.2 mm and H 3.0 mm, that is, 7.5 mm posterior to the anterior fontanelle, 4.2 mm laterally on the right side and 3.0 mm under the subcortex. The subcortex recorder electrode coordinates are AP 3.8 mm, L 2.5 mm and H 3.5 mm, located in the granular cell layer of the unilateral dentate gyrus (DG) of hippocampus, at the site of which an opening with the diameter of 1.5 mm was drilled for the purpose of embedding of the stimulating and recording electrodes, and at the site by mild adjusting the positions of these electrodes where maximal population spike (PS) was recorded, fastened the electrodes at last. ② The 60 rats were randomized into two major groups, namely, fundamental stimulation (FS) group (basic group) and high frequency stimulation (HFS) group. Each group was further divided into three subgroups respectively: Sham-operated subgroup (n=10): only exposed bilateral common carotid arteries without blocking their blood flow; Cerebral ischemia model subgroup (n=10): exposing bilateral common carotid arteries and blocking their blood flow; Ischemia plus electroacupuncture subgroup (n=10): blocked blood flow of bilateral common carotid arteries and received electroacupuncture. The electroacupuncture acupoints were the points of Du meridian, including Baihui (GV20), Dazhui (GV14), and points of Pen meridian, including Qihai (CV6) and Guanyuan (CV4). ③ Process of electroacupuncture: All the rats underwent testing stimulation (1/30 Hz frequency and 0.1 ms breadth) at 30 minutes before modeling, PS values were recorded as the indexes of the excitation of DG granular cell population, and the data were input to computer for data analysis. During the experiment, the intensity of stimulation was kept stable by adopting 1/2 the value of stimulation intensity that could induce maximal PS amplitude. In the basic group, PS were recorded for 120 minutes after modeling, and among the rats in the electroacupuncture group, PS was recorded at 10 minutes before and 60 minutes after blocking blood flow in the carotid artery during continuous electrical acupuncture. In the HFS group, HFS was given immediately after modeling, PS were recorded for 180 minutes at 10 minutes after HFS was given in the sham-operated group and model group, rats in the electroacupuncture group were treated with electroacupuncture for 60 minutes at 30 minutes after HFS was given, and PS was recorded for 180 minutes after 10 minutes. LTP was triggered by HFS and PS values were determined and recorded through measuring stimulations respectively 0, 10, 30, 60, 120 and 180 minutes after the evokes.④ Methods for expressing the level of synaptic transmission: Each testing stimulus provoked one PS, and 10 successive amplitude values (V/mV) were averaged relevant to a certain time cut. The averaged PS of 6 time cuts at 30 minutes before modeling was made as basal synaptic transmission level as control. Synaptic transmission at each time cut was expressed as: p=( Vdifferentime cut / Vbasal) × 100%. MAIN OUTCOME MEASURES: The differences of synaptic transmission level were compared among the subgroups in the basic group after models also among the subgroups in the HFS group after HFS.RESULTS: All the 60 rats were involved in the analysis of results. ① Comparison of synaptic transmission level at different time cut after modeling and the effect of electroacupuncture in the subgroups of the basic group: The synaptic transmission level in the sham-operated subgroup had no significant change within 120 minutes (P 〉 0.05). The synaptic transmission levels at 10, 30 and 60 minutes in the model subgroup were obviously lower than those in the sham-operated group [(60±7)%, (90±3)%, (93±4)%; (100±5)%, (102±6)%, (105±7)%, P 〈 0.05-0.01]. With the prolongation of time for ischemia/reperfusion, the synaptic transmission level gradually ascended to the normal level, and those at 90 and 120 minutes were close to those in the sham-operated group (P 〉 0.05). In the subgroup of electroacupuncture, the synaptic transmission levels at 10, 30, 60, 90 and 120 minutes were obviously higher than those in the model subgroup [(93±5)%, (106±10)%, (123±16)%, (145±20)%, (168±25)%; (96±7)%, (98±8)%, P 〈 0.05-0.01].② Comparison of synaptic transmission level at different time cut after HFS and the effect of electroacupuncture in the groups: In the sham-operated group, the synaptic transmission level after HFS increased significantly, and maintained without decrease within 180 minutes. In the model group, the synaptic transmission level at 0, 10, 30, 60, 120 and 180 minutes after HFS were obviously lower than those in the sham-operated group [(60±7)%, (95±9)%, (138±11)%, (141±13)%, (140±13)%, (138±15)%; (100±6)%, (182±21)%, (179±18)%, (177±18)%, (175±23)%, (178±24)%, P 〈 0.01]. The synaptic transmission level at 60, 120 and 180 minutes after HFS in the electroacupuncture group were close to those in the sham-operated group (P 〉 0.05), those at 120 and 180 minutes after HFS in the electroacupuncture group were obviously higher than those in the model group [(171±22)%, (181±25)%, P 〈 0.05-0.01]. CONCLUSION: Electroacupuncture could enhance the basic activity of synaptic transmission in the dentate gyros of hippocampus in cerebral ischemic injury in rats. Electroacupuncture has obvious LTP effect on the activity of synaptic transmission induced by HFS.展开更多
Based on time series data of RMB exchange rate and urban-rural income, this paper makes an empirical study for the influence of RMB exchange rate fluctuation on urban-rural income by utilizing rolling regression model...Based on time series data of RMB exchange rate and urban-rural income, this paper makes an empirical study for the influence of RMB exchange rate fluctuation on urban-rural income by utilizing rolling regression model through direct and indirect transmission mechanisms. According to the results, the transmission effect of RMB exchange rate fluctuation on urban-rural income has features of incompleteness and asymmetry. Moreover, RMB appreciation will help to reduce the urban-rural income gap. Therefore, this paper suggests that the Chinese economy should accelerate the course of transforming mode, adjusting structure and promoting development under the new normal. Meanwhile, reform of RMB exchange rate mechanism should be promoted, living standard of residents must be improved, and the urban-rural income gap should be reduced.展开更多
In the context of global carbon neutrality,new energy vehicle promotion(NEVP)has become an important means of reducing carbon emissions.This paper constructs a theoretical model and uses panel data on NEVP in 21 count...In the context of global carbon neutrality,new energy vehicle promotion(NEVP)has become an important means of reducing carbon emissions.This paper constructs a theoretical model and uses panel data on NEVP in 21 countries from 2012 to 2018 to empirically examine the green effect of NEVP.The results indicate the following:(1)NEVP significantly reduces greenhouse gases emissions,and the green effect can be transmitted and diffused through a direct path.(2)Replacing fuel-fired vehicles and accelerating the end-of-life vehicle scrapping process significantly conducted the green effect,and aggravating traffic congestion was not statistically significant.(3)The transmission mechanism of the green effect is regulated by regional economic heterogeneity.In regions with better development of fuel-fired vehicles,the transmission of the green effect is subject to the elimination of fuel-fired vehicles and traffic congestion governance,and the transmission efficiency is low.However,regions with a relatively weak fuel-fired automobile industry foundation show a strong“advantage of backwardness”,and the green effect is more prominent.This means that global NEVP should be further accelerated to achieve the green effect and the goal of global carbon neutrality.展开更多
Deep synthesis technology is an emerging artificial intelligence technology.There have been a large number of audio and video contents based on deep synthesis technology spreading in the Internet.In this paper,we take...Deep synthesis technology is an emerging artificial intelligence technology.There have been a large number of audio and video contents based on deep synthesis technology spreading in the Internet.In this paper,we take the deep synthetic videos on YouTube platform as the research object,and investigate the factors influencing the propagation effect of deep synthetic videos by establishing an ordered probit model.It is found that the effect of deep synthesized video transmission of YouTube platform is mainly influenced by factors such as the video type,video duration,influence of publishers and forms of fraud.In addition,the comparative analysis of ordinary video and in-depth synthesized video reveals that both the video transmission effect are significantly affected by the video type,video duration and the influence of publishers.展开更多
Using numerical simulations, the nonlinear transmission performance of polarization-division-multiplexed quadrature-phase-shift-keying (PDM-QPSK) coherent systems is studied. It is found that inter-channel cross-pol...Using numerical simulations, the nonlinear transmission performance of polarization-division-multiplexed quadrature-phase-shift-keying (PDM-QPSK) coherent systems is studied. It is found that inter-channel cross-polarization modulation (XPolM) induced nonlinear polarization scattering can significantly degrade the transmission performance of PDM-QPSK coherent systems and change the perspective of dispersion management in optical coherent transmission systems. Some techniques to mitigate nonlinear polarization scattering in dispersion-managed PDM coherent transmission systems are discussed, including the use of time-interleaved return-to-zero (RZ) PDM formats, the use of periodic-group-delay PGD dispersion compensators, and the judicious addition of some polarization-mode-dispersion (PMD) in the transmission link. It is shown that if nonlinear polarization scattering can be well mitigated, a polarization multiplexed optical coherent transmission system with dispersion management could perform better than that without it.展开更多
PPM encoded Gaussian pulse sequence shows more immunity than non-PPM schemes on optical fiber intra-channel nonlinearity and demonstrated by a numerical study of IXPM and IFWM effects deploying on 100Gb/s single chann...PPM encoded Gaussian pulse sequence shows more immunity than non-PPM schemes on optical fiber intra-channel nonlinearity and demonstrated by a numerical study of IXPM and IFWM effects deploying on 100Gb/s single channelsystem.展开更多
We report on the effects of the polarization-dependent loss (PDL) on the polarization-multiplexed system. The result shows that the PDL of 0.9 dB could cause 1-dB power penalty. Unlike PMD, the effect of PDL was not d...We report on the effects of the polarization-dependent loss (PDL) on the polarization-multiplexed system. The result shows that the PDL of 0.9 dB could cause 1-dB power penalty. Unlike PMD, the effect of PDL was not dependent on the transmission speed.展开更多
The effects of optical losses oil a directly-modulated radio-over-fiber (RoF) system used for distributed antenna networks are determined. The results show that with a properly designed bidirectional amplifier, the ...The effects of optical losses oil a directly-modulated radio-over-fiber (RoF) system used for distributed antenna networks are determined. The results show that with a properly designed bidirectional amplifier, the RoF link can tolerate over 20 and 16 dB of optical losses for down- and up-links, respectively. Simulation results are also consistent with the experimental data. These findings can contribute to tile design of RoF distributed antenna systems with different topologies.展开更多
In summary,the interval uncertainty is introduced to the acoustic metamaterial with Helmholtz resonators.And then,new descriptions(the conservative approximation,the unsafe approximation and the approximation precisio...In summary,the interval uncertainty is introduced to the acoustic metamaterial with Helmholtz resonators.And then,new descriptions(the conservative approximation,the unsafe approximation and the approximation precision)on uncertainties of physical properties of this interval acoustic metamaterial are defined.Lastly,an optimization model for this interval acoustic metamaterial is proposed.The organization of this paper is listed as follows.The acoustic transmission line method(ATLM)for an acoustic metamaterial with Helmholtz resonators is described in Section 2.In Section3,uncertain analysis of the interval acoustic metamaterial is presented.In Section 4,optimization model of the interval acoustic metamaterial is proposed.The discussion on optimization results is shown in Section 5.In section 6,some conclusions are given.展开更多
GaSb is the most suitable substrate in the epitaxial growth of mixed semiconductors of GaSb system.In this work,Te-doped GaSb bulk crystals with different doping concentration have been annealed at 550℃ for100 h in a...GaSb is the most suitable substrate in the epitaxial growth of mixed semiconductors of GaSb system.In this work,Te-doped GaSb bulk crystals with different doping concentration have been annealed at 550℃ for100 h in ambient antimony.The annealed samples have been studied by Hall effect measurement,infrared(IR)optical transmission,Glow discharge mass spectroscopy(GDMS) and photoluminescence(PL) spectroscopy.After annealing,Te-doped GaSb samples exhibit a decrease of carrier concentration and increase of mobility,along with an improvement of below gap IR transmission.Native acceptor related electrical compensation analysis suggests a formation of donor defect with deeper energy level.The mechanism of the variation of the defect and its influence on the material properties are discussed.展开更多
基金Projects(71633006,71573282)supported by the National Natural Science Foundation of China
文摘Based on a new perspective of industry chain and selecting monthly data from February2006to December2015,this paper chooses eight Chinese industrial sectors to construct a SVAR model reflecting internal relationships among metal chains,analyzes the direct effects and indirect effects of international metal prices on output of various links in metal chains,then it investigates the main transmission path of international metal price shocks through decomposing the inflation pressure sources in metal chains.The results show that international metal price shocks not only affect industrial output in a direct way,but also indirectly affect the growth of output through the increased pressure on industrial inflation and then triggering a tightening of monetary policy implementation.Affected by factors such as the lack of market demand and the price transmission mechanism blocking,the direct effects of international metal price shocks mainly impact the upstream and midstream industry,while the downstream industry is mainly affected by indirect effects;in addition,the international metal price shocks have spillover effects on the industrial inflation,and transmit along the industry chain from upstream to downstream,and their strength weakens in sequence.
基金Supported by the National Natural Science Foun-dation of China (60572049) the Natural Science Foundation ofHubei Province of China (2005ABA264)
文摘In order to minimize the energy consumption in the discovery of the routing path, this paper introduces a novel concept of effective transmission (ET) that ensures each forwarding node is not only farther from the source node, but also nearer to the destination node with respect to its sender, An energ-aware routing protocol based on ET is proposed. It enables the energy consumption for each hop to be the least for the transmission. The simulation results show the routing protocol is effective in the performance of energy consumption comparing with some other routing protocols.
文摘BACKGROUND: Some studies suggest that the long-term potentiation (LTP) of synaptic transmission may be the basis for the neural synaptic plasticity of hippocampus, but can be evoked by various factors including electroacupuncture. OBJECTIVE: To observe the effect of electroacupuncture on the activities of basic synaptic transmission in dentate gyrus of hippocampus and the changes of high frequency stimulation (HFS) induced activity of synaptic transmission in cerebral ischemic injured rats. DESIGN: A randomized control trial.SETTING: Shenzhen Hospital of Traditional Chinese Medicine affiliated to Guangzhou University of Traditional Chinese Medicine. MATERIALS: Sixty healthy male Wistar rats, weighing 150-250 g, were provided by the Experimental Animal Center of Guangzhou University of Traditional Chinese Medicine. The experiment began after adaptation of environment for 1 week under standard experimental environment. The main experimental instruments included the programming electrical acupuncture apparatus (PCEA, product of the Institute of Acupuncture and Meridians, Anhui College of Traditional Chinese Medicine) and multichannel physiologic recorder (RM-86, Nihon Konden). METHODS: The experiment was carried out in Guangzhou University of Traditional Chinese Medicine between July 2003 and July 2004. ①Embedding of brain electrodes: In reference of the Pellegrino's rat brain atlas, the bipolar electrode stimulator was embedded into the perforant path (PP) anterior to the entorhinal area with location coordinates of AP 7.5 mm, L 4.2 mm and H 3.0 mm, that is, 7.5 mm posterior to the anterior fontanelle, 4.2 mm laterally on the right side and 3.0 mm under the subcortex. The subcortex recorder electrode coordinates are AP 3.8 mm, L 2.5 mm and H 3.5 mm, located in the granular cell layer of the unilateral dentate gyrus (DG) of hippocampus, at the site of which an opening with the diameter of 1.5 mm was drilled for the purpose of embedding of the stimulating and recording electrodes, and at the site by mild adjusting the positions of these electrodes where maximal population spike (PS) was recorded, fastened the electrodes at last. ② The 60 rats were randomized into two major groups, namely, fundamental stimulation (FS) group (basic group) and high frequency stimulation (HFS) group. Each group was further divided into three subgroups respectively: Sham-operated subgroup (n=10): only exposed bilateral common carotid arteries without blocking their blood flow; Cerebral ischemia model subgroup (n=10): exposing bilateral common carotid arteries and blocking their blood flow; Ischemia plus electroacupuncture subgroup (n=10): blocked blood flow of bilateral common carotid arteries and received electroacupuncture. The electroacupuncture acupoints were the points of Du meridian, including Baihui (GV20), Dazhui (GV14), and points of Pen meridian, including Qihai (CV6) and Guanyuan (CV4). ③ Process of electroacupuncture: All the rats underwent testing stimulation (1/30 Hz frequency and 0.1 ms breadth) at 30 minutes before modeling, PS values were recorded as the indexes of the excitation of DG granular cell population, and the data were input to computer for data analysis. During the experiment, the intensity of stimulation was kept stable by adopting 1/2 the value of stimulation intensity that could induce maximal PS amplitude. In the basic group, PS were recorded for 120 minutes after modeling, and among the rats in the electroacupuncture group, PS was recorded at 10 minutes before and 60 minutes after blocking blood flow in the carotid artery during continuous electrical acupuncture. In the HFS group, HFS was given immediately after modeling, PS were recorded for 180 minutes at 10 minutes after HFS was given in the sham-operated group and model group, rats in the electroacupuncture group were treated with electroacupuncture for 60 minutes at 30 minutes after HFS was given, and PS was recorded for 180 minutes after 10 minutes. LTP was triggered by HFS and PS values were determined and recorded through measuring stimulations respectively 0, 10, 30, 60, 120 and 180 minutes after the evokes.④ Methods for expressing the level of synaptic transmission: Each testing stimulus provoked one PS, and 10 successive amplitude values (V/mV) were averaged relevant to a certain time cut. The averaged PS of 6 time cuts at 30 minutes before modeling was made as basal synaptic transmission level as control. Synaptic transmission at each time cut was expressed as: p=( Vdifferentime cut / Vbasal) × 100%. MAIN OUTCOME MEASURES: The differences of synaptic transmission level were compared among the subgroups in the basic group after models also among the subgroups in the HFS group after HFS.RESULTS: All the 60 rats were involved in the analysis of results. ① Comparison of synaptic transmission level at different time cut after modeling and the effect of electroacupuncture in the subgroups of the basic group: The synaptic transmission level in the sham-operated subgroup had no significant change within 120 minutes (P 〉 0.05). The synaptic transmission levels at 10, 30 and 60 minutes in the model subgroup were obviously lower than those in the sham-operated group [(60±7)%, (90±3)%, (93±4)%; (100±5)%, (102±6)%, (105±7)%, P 〈 0.05-0.01]. With the prolongation of time for ischemia/reperfusion, the synaptic transmission level gradually ascended to the normal level, and those at 90 and 120 minutes were close to those in the sham-operated group (P 〉 0.05). In the subgroup of electroacupuncture, the synaptic transmission levels at 10, 30, 60, 90 and 120 minutes were obviously higher than those in the model subgroup [(93±5)%, (106±10)%, (123±16)%, (145±20)%, (168±25)%; (96±7)%, (98±8)%, P 〈 0.05-0.01].② Comparison of synaptic transmission level at different time cut after HFS and the effect of electroacupuncture in the groups: In the sham-operated group, the synaptic transmission level after HFS increased significantly, and maintained without decrease within 180 minutes. In the model group, the synaptic transmission level at 0, 10, 30, 60, 120 and 180 minutes after HFS were obviously lower than those in the sham-operated group [(60±7)%, (95±9)%, (138±11)%, (141±13)%, (140±13)%, (138±15)%; (100±6)%, (182±21)%, (179±18)%, (177±18)%, (175±23)%, (178±24)%, P 〈 0.01]. The synaptic transmission level at 60, 120 and 180 minutes after HFS in the electroacupuncture group were close to those in the sham-operated group (P 〉 0.05), those at 120 and 180 minutes after HFS in the electroacupuncture group were obviously higher than those in the model group [(171±22)%, (181±25)%, P 〈 0.05-0.01]. CONCLUSION: Electroacupuncture could enhance the basic activity of synaptic transmission in the dentate gyros of hippocampus in cerebral ischemic injury in rats. Electroacupuncture has obvious LTP effect on the activity of synaptic transmission induced by HFS.
文摘Based on time series data of RMB exchange rate and urban-rural income, this paper makes an empirical study for the influence of RMB exchange rate fluctuation on urban-rural income by utilizing rolling regression model through direct and indirect transmission mechanisms. According to the results, the transmission effect of RMB exchange rate fluctuation on urban-rural income has features of incompleteness and asymmetry. Moreover, RMB appreciation will help to reduce the urban-rural income gap. Therefore, this paper suggests that the Chinese economy should accelerate the course of transforming mode, adjusting structure and promoting development under the new normal. Meanwhile, reform of RMB exchange rate mechanism should be promoted, living standard of residents must be improved, and the urban-rural income gap should be reduced.
文摘In the context of global carbon neutrality,new energy vehicle promotion(NEVP)has become an important means of reducing carbon emissions.This paper constructs a theoretical model and uses panel data on NEVP in 21 countries from 2012 to 2018 to empirically examine the green effect of NEVP.The results indicate the following:(1)NEVP significantly reduces greenhouse gases emissions,and the green effect can be transmitted and diffused through a direct path.(2)Replacing fuel-fired vehicles and accelerating the end-of-life vehicle scrapping process significantly conducted the green effect,and aggravating traffic congestion was not statistically significant.(3)The transmission mechanism of the green effect is regulated by regional economic heterogeneity.In regions with better development of fuel-fired vehicles,the transmission of the green effect is subject to the elimination of fuel-fired vehicles and traffic congestion governance,and the transmission efficiency is low.However,regions with a relatively weak fuel-fired automobile industry foundation show a strong“advantage of backwardness”,and the green effect is more prominent.This means that global NEVP should be further accelerated to achieve the green effect and the goal of global carbon neutrality.
文摘Deep synthesis technology is an emerging artificial intelligence technology.There have been a large number of audio and video contents based on deep synthesis technology spreading in the Internet.In this paper,we take the deep synthetic videos on YouTube platform as the research object,and investigate the factors influencing the propagation effect of deep synthetic videos by establishing an ordered probit model.It is found that the effect of deep synthesized video transmission of YouTube platform is mainly influenced by factors such as the video type,video duration,influence of publishers and forms of fraud.In addition,the comparative analysis of ordinary video and in-depth synthesized video reveals that both the video transmission effect are significantly affected by the video type,video duration and the influence of publishers.
文摘Using numerical simulations, the nonlinear transmission performance of polarization-division-multiplexed quadrature-phase-shift-keying (PDM-QPSK) coherent systems is studied. It is found that inter-channel cross-polarization modulation (XPolM) induced nonlinear polarization scattering can significantly degrade the transmission performance of PDM-QPSK coherent systems and change the perspective of dispersion management in optical coherent transmission systems. Some techniques to mitigate nonlinear polarization scattering in dispersion-managed PDM coherent transmission systems are discussed, including the use of time-interleaved return-to-zero (RZ) PDM formats, the use of periodic-group-delay PGD dispersion compensators, and the judicious addition of some polarization-mode-dispersion (PMD) in the transmission link. It is shown that if nonlinear polarization scattering can be well mitigated, a polarization multiplexed optical coherent transmission system with dispersion management could perform better than that without it.
文摘PPM encoded Gaussian pulse sequence shows more immunity than non-PPM schemes on optical fiber intra-channel nonlinearity and demonstrated by a numerical study of IXPM and IFWM effects deploying on 100Gb/s single channelsystem.
文摘We report on the effects of the polarization-dependent loss (PDL) on the polarization-multiplexed system. The result shows that the PDL of 0.9 dB could cause 1-dB power penalty. Unlike PMD, the effect of PDL was not dependent on the transmission speed.
基金supported by the National "863" Program of China(No.2011AA010306)the National "973" Program of China(No.2012CB315705)+2 种基金the National Natural Science Foundation of China(Nos.61107058,61120106001,60932004,61001121,and 60837004)the Beijing Excellent Doctoral Thesis Project(No.YB20101001301)the Cooperation Project between Province and Ministries(No.2011A090200025)
文摘The effects of optical losses oil a directly-modulated radio-over-fiber (RoF) system used for distributed antenna networks are determined. The results show that with a properly designed bidirectional amplifier, the RoF link can tolerate over 20 and 16 dB of optical losses for down- and up-links, respectively. Simulation results are also consistent with the experimental data. These findings can contribute to tile design of RoF distributed antenna systems with different topologies.
基金supported by National Natural Science Foundation of China(Grant Nos.11402083&11572121)Independent Research Project of State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body in Hunan University(Grant No.51375002)Fundamental Research Funds for the Central Universities,Collaborative Innovation Center of Intelligent New Energy Vehicle,and the Hunan Collaborative Innovation Center of Green Automobile
文摘In summary,the interval uncertainty is introduced to the acoustic metamaterial with Helmholtz resonators.And then,new descriptions(the conservative approximation,the unsafe approximation and the approximation precision)on uncertainties of physical properties of this interval acoustic metamaterial are defined.Lastly,an optimization model for this interval acoustic metamaterial is proposed.The organization of this paper is listed as follows.The acoustic transmission line method(ATLM)for an acoustic metamaterial with Helmholtz resonators is described in Section 2.In Section3,uncertain analysis of the interval acoustic metamaterial is presented.In Section 4,optimization model of the interval acoustic metamaterial is proposed.The discussion on optimization results is shown in Section 5.In section 6,some conclusions are given.
基金Project supported by the National Natural Science Foundation of China(Nos.61474104,61504131)
文摘GaSb is the most suitable substrate in the epitaxial growth of mixed semiconductors of GaSb system.In this work,Te-doped GaSb bulk crystals with different doping concentration have been annealed at 550℃ for100 h in ambient antimony.The annealed samples have been studied by Hall effect measurement,infrared(IR)optical transmission,Glow discharge mass spectroscopy(GDMS) and photoluminescence(PL) spectroscopy.After annealing,Te-doped GaSb samples exhibit a decrease of carrier concentration and increase of mobility,along with an improvement of below gap IR transmission.Native acceptor related electrical compensation analysis suggests a formation of donor defect with deeper energy level.The mechanism of the variation of the defect and its influence on the material properties are discussed.