Identifying vital nodes is one of the core issues of network science,and is crucial for epidemic prevention and control,network security maintenance,and biomedical research and development.In this paper,a new vital no...Identifying vital nodes is one of the core issues of network science,and is crucial for epidemic prevention and control,network security maintenance,and biomedical research and development.In this paper,a new vital nodes identification method,named degree and cycle ratio(DC),is proposed by integrating degree centrality(weightα)and cycle ratio(weight 1-α).The results show that the dynamic observations and weightαare nonlinear and non-monotonicity(i.e.,there exists an optimal valueα^(*)forα),and that DC performs better than a single index in most networks.According to the value ofα^(*),networks are classified into degree-dominant networks(α^(*)>0.5)and cycle-dominant networks(α^(*)<0.5).Specifically,in most degree-dominant networks(such as Chengdu-BUS,Chongqing-BUS and Beijing-BUS),degree is dominant in the identification of vital nodes,but the identification effect can be improved by adding cycle structure information to the nodes.In most cycle-dominant networks(such as Email,Wiki and Hamsterster),the cycle ratio is dominant in the identification of vital nodes,but the effect can be notably enhanced by additional node degree information.Finally,interestingly,in Lancichinetti-Fortunato-Radicchi(LFR)synthesis networks,the cycle-dominant network is observed.展开更多
A new method of using dynamic equalization technology to realize the maximum energy storage utilization was presented to overcome the influence of the disaccord among units of series super capacitor （SC） bank and en...A new method of using dynamic equalization technology to realize the maximum energy storage utilization was presented to overcome the influence of the disaccord among units of series super capacitor （SC） bank and ensure that the units could work safely. By considering in combination with the high specific power, low working voltage, wide voltage working range and noulinear external characteristics, we present constant duty ratio pulse frequency modulation mode and fuzzy control method based on state prediction in the active equalization circuit and accomplish the software and hardware design for the equalization system. The simulation analysis and experiment results of constant current muhi-cycle and variable current multi-cycle charge-discharge process verify the validity of the design.展开更多
Middle and low temperature thermal energy widely exists in the natural world and many industrial fields.Unlike fossil fuel power generation systems,the significant feature of middle and low temperature power generatio...Middle and low temperature thermal energy widely exists in the natural world and many industrial fields.Unlike fossil fuel power generation systems,the significant feature of middle and low temperature power generation systems is the temperature constraint of the heat source.Exploring the potential of the cycle within a limited temperature range is key to improve energy utilization efficiency.This study proposes the conception of supercritical organic fluid Brayton cycles (SOFBC) and evaluates the feasibility and application potential.R116,R23,R170 and N_(2)O are selected as the working fluids for cycle analysis based on their thermal properties.Then,thermodynamic models of the supercritical gas Brayton cycle based on simple regeneration and organic Rankine cycles (ORCs) have been established.According to the calculation results,the performances of regenerative Brayton cycles (RBCs) using four working fluids are better than that of CO_(2).The maximum thermal efficiencies of R116,R23,and R170 are 41.9%,20.2%,and 15.3%higher than that of CO_(2)at the highest temperature of 150℃.Even at 300℃,the corresponding values of three organic fluids are 25.6%,13.7%,and 13.7%higher than that of CO_(2).By analyzing the variations in isobaric specific heat capacity (c_(p)) of different working fluids,it is found that the c_(p) difference between the high and low pressure sides in the regenerator of CO_(2) is significantly higher than that of organic working fluids.Additionally,the performance of RBCs using R116 is better than the sub-ORC using R123 and the trans-RORC using R236fa at the same temperature range.The results can demonstrate that the SOFBC is superior in middle and low temperature power generation compared with the sCO_(2) Brayton cycle and ORCs.This study provides preliminary and rough evidence of the feasibility and potential for SOFBCs.展开更多
Al doped ZnO（AZO） films deposited on glass substrates through the atomic layer deposition（ALD）technique are investigated with various temperatures from 100 to 250 °C and different Zn ： Al cycle ratios from20...Al doped ZnO（AZO） films deposited on glass substrates through the atomic layer deposition（ALD）technique are investigated with various temperatures from 100 to 250 °C and different Zn ： Al cycle ratios from20 ： 0 to 20 ： 3. Surface morphology, structure, optical and electrical properties of obtained AZO films are studied in detail. The Al composition of the AZO films is varied by controlling the ratio of Zn ： Al. We achieve an excellent AZO thin film with a resistivity of 2.14 × 10^（-3）Ω·cm and high optical transmittance deposited at 150 °C with20 ： 2 Zn ： Al cycle ratio. This kind of AZO thin films exhibit great potential for optoelectronics device application.展开更多
基金Project supported by Yunnan Fundamental Research Projects(Grant No.202401AT070359)。
文摘Identifying vital nodes is one of the core issues of network science,and is crucial for epidemic prevention and control,network security maintenance,and biomedical research and development.In this paper,a new vital nodes identification method,named degree and cycle ratio(DC),is proposed by integrating degree centrality(weightα)and cycle ratio(weight 1-α).The results show that the dynamic observations and weightαare nonlinear and non-monotonicity(i.e.,there exists an optimal valueα^(*)forα),and that DC performs better than a single index in most networks.According to the value ofα^(*),networks are classified into degree-dominant networks(α^(*)>0.5)and cycle-dominant networks(α^(*)<0.5).Specifically,in most degree-dominant networks(such as Chengdu-BUS,Chongqing-BUS and Beijing-BUS),degree is dominant in the identification of vital nodes,but the identification effect can be improved by adding cycle structure information to the nodes.In most cycle-dominant networks(such as Email,Wiki and Hamsterster),the cycle ratio is dominant in the identification of vital nodes,but the effect can be notably enhanced by additional node degree information.Finally,interestingly,in Lancichinetti-Fortunato-Radicchi(LFR)synthesis networks,the cycle-dominant network is observed.
基金the National High Technology Research and Development Programme of China(No.2002AA001028)the Tenth Five-year Industry Item of the Tackling Key Problem of Heilongjiang Province(No.CA02A201)
文摘A new method of using dynamic equalization technology to realize the maximum energy storage utilization was presented to overcome the influence of the disaccord among units of series super capacitor （SC） bank and ensure that the units could work safely. By considering in combination with the high specific power, low working voltage, wide voltage working range and noulinear external characteristics, we present constant duty ratio pulse frequency modulation mode and fuzzy control method based on state prediction in the active equalization circuit and accomplish the software and hardware design for the equalization system. The simulation analysis and experiment results of constant current muhi-cycle and variable current multi-cycle charge-discharge process verify the validity of the design.
基金supported by Beijing Natural Science Foundation of China (Grant No.3222025)。
文摘Middle and low temperature thermal energy widely exists in the natural world and many industrial fields.Unlike fossil fuel power generation systems,the significant feature of middle and low temperature power generation systems is the temperature constraint of the heat source.Exploring the potential of the cycle within a limited temperature range is key to improve energy utilization efficiency.This study proposes the conception of supercritical organic fluid Brayton cycles (SOFBC) and evaluates the feasibility and application potential.R116,R23,R170 and N_(2)O are selected as the working fluids for cycle analysis based on their thermal properties.Then,thermodynamic models of the supercritical gas Brayton cycle based on simple regeneration and organic Rankine cycles (ORCs) have been established.According to the calculation results,the performances of regenerative Brayton cycles (RBCs) using four working fluids are better than that of CO_(2).The maximum thermal efficiencies of R116,R23,and R170 are 41.9%,20.2%,and 15.3%higher than that of CO_(2)at the highest temperature of 150℃.Even at 300℃,the corresponding values of three organic fluids are 25.6%,13.7%,and 13.7%higher than that of CO_(2).By analyzing the variations in isobaric specific heat capacity (c_(p)) of different working fluids,it is found that the c_(p) difference between the high and low pressure sides in the regenerator of CO_(2) is significantly higher than that of organic working fluids.Additionally,the performance of RBCs using R116 is better than the sub-ORC using R123 and the trans-RORC using R236fa at the same temperature range.The results can demonstrate that the SOFBC is superior in middle and low temperature power generation compared with the sCO_(2) Brayton cycle and ORCs.This study provides preliminary and rough evidence of the feasibility and potential for SOFBCs.
基金Project supported by the State Key Development Program for Basic Research of China(Nos.2011CBA00706,2011CBA00707)the Tianjin Applied Basic Research Project and Cutting-Edge Technology Research Plan(No.13JCZDJC26900)
文摘Al doped ZnO（AZO） films deposited on glass substrates through the atomic layer deposition（ALD）technique are investigated with various temperatures from 100 to 250 °C and different Zn ： Al cycle ratios from20 ： 0 to 20 ： 3. Surface morphology, structure, optical and electrical properties of obtained AZO films are studied in detail. The Al composition of the AZO films is varied by controlling the ratio of Zn ： Al. We achieve an excellent AZO thin film with a resistivity of 2.14 × 10^（-3）Ω·cm and high optical transmittance deposited at 150 °C with20 ： 2 Zn ： Al cycle ratio. This kind of AZO thin films exhibit great potential for optoelectronics device application.
