With the rapid development and popularization of artificial intelligence technology,convolutional neural network(CNN)is applied in many fields,and begins to replace most traditional algorithms and gradually deploys to...With the rapid development and popularization of artificial intelligence technology,convolutional neural network(CNN)is applied in many fields,and begins to replace most traditional algorithms and gradually deploys to terminal devices.However,the huge data movement and computational complexity of CNN bring huge power consumption and performance challenges to the hardware,which hinders the application of CNN in embedded devices such as smartphones and smart cars.This paper implements a convolutional neural network accelerator based on Winograd convolution algorithm on field-programmable gate array(FPGA).Firstly,a convolution kernel decomposition method for Winograd convolution is proposed.The convolution kernel larger than 3×3 is divided into multiple 3×3 convolution kernels for convolution operation,and the unsynchronized long convolution operation is processed.Then,we design Winograd convolution array and use configurable multiplier to flexibly realize multiplication for data with different accuracy.Experimental results on VGG16 and AlexNet network show that our accelerator has the most energy efficient and 101 times that of the CPU,5.8 times that of the GPU.At the same time,it has higher energy efficiency than other convolutional neural network accelerators.展开更多
The Naxi of Northwest Yunnan,China use medicinal plants to treat skin conditions related to traditional lifestyles in extreme environments.However,modernization endangers both the medicinal plants used to treat skin c...The Naxi of Northwest Yunnan,China use medicinal plants to treat skin conditions related to traditional lifestyles in extreme environments.However,modernization endangers both the medicinal plants used to treat skin conditions and traditional knowledge.Therefore,investigation and documentation of the medicinal plants used and associated traditional knowledge is necessary.In this study,we conducted an ethnobotanical survey in 12 Naxi communities in Northwest Yunnan.For this purpose,we used semistructured surveys to interview 840 informants from Naxi communities.We used informant consensus factor and use frequency as quantitative indices to evaluate the importance of medicinal plant species.A total of 161 medicinal plant species belonging to 69 families were documented.The highest informant consensus factor(ICF)values were recorded for skin nourishing(ICF?0.849),frostbite and chapped skin(ICF?0.833).These skin treatments are highly related to the environment and lifestyle of Naxi communities.The main active compounds of plants used to treat skin conditions in Naxi communities are known to have skin-treating properties.This study reveals that the skin conditions treated by the Naxi are associated with traditional medicine culture and social economic development.In addition,this study uses ethnobotanical indices to explain how skin condition treatments are linked to the natural environment of Naxi communities.展开更多
The concept of eco-civilisation refers to the need for human affairs to be contained within the limits set by nature.Plants play such fundamental roles in the functioning of ecosystems and economies that due attention...The concept of eco-civilisation refers to the need for human affairs to be contained within the limits set by nature.Plants play such fundamental roles in the functioning of ecosystems and economies that due attention must be given to them for eco-civilisation to be achieved.Species are the basic functional units of the plant world and,taking a long term perspective,their conservation with their genetic diversity should be a primary objective in eco-civilisation construction.However,standard procedures used for plant conservation have met with only limited success.Therefore,plant conservationists need social allies to boost their efforts-referring to elements of society whose primary interests in eco-civilisation construction are different,but whose efforts,if successful,will bring benefits to plant conservation too.Potential allies can be identified using an ecosystem system services framework showing how benefits received from the delivery of ecosystem services overlap with those that favour conservation of plant diversity.The concept of eco-civilisation was adopted officially in China in 2014 as a principle guiding its future development.A project at Ludian,Yunnan Province,is used to show the relationships between an ecosystem services framework and a conservation initiative.展开更多
In this paper,a mode-locked Ytterbiumdoped fiber laser based on nonlinear optical loop mirror(NOLM)is proposed.The laser generates a wide-spectrum dissipative soliton resonance modelocked pulse with strong stimulated ...In this paper,a mode-locked Ytterbiumdoped fiber laser based on nonlinear optical loop mirror(NOLM)is proposed.The laser generates a wide-spectrum dissipative soliton resonance modelocked pulse with strong stimulated Raman scattering.The fiber laser is pumped forward,and the fiber ring cavity contains double-cladding Yb-doped fiber,output coupler,polarization controller,polarization independent isolator and other elements.NOLM is connected with the ring cavity by through a 3dB beam splitter and 25m single-mode fiber.The total length of the eight-shape cavity laser is about 60meters.By adjusting the intra-cavity polarization controller,a stable dissipative soliton resonance mode-locked spike pulse can be achieved.The repetition frequency of the pulse train is 3.44MHz,which is consistent with the cavity length.The 3dB bandwidth of the spectrum reaches 70.6nm,and the 10dB bandwidth is close to 147.11nm.In this experiment,dissipative soliton resonance mode-locked pulses with wide spectrum and high pulse energy are realized by a traditional modelocking method,which has wide application in many fields such as laser spectral detection and terahertz wave generation.展开更多
This study was conducted to compare the perinatal complications for newborns by In vitro fertilization with embryo transfer(IVF-ET)and natural delivery.Respectively 50 cases of the IVF-ET and 50 cases of the natural d...This study was conducted to compare the perinatal complications for newborns by In vitro fertilization with embryo transfer(IVF-ET)and natural delivery.Respectively 50 cases of the IVF-ET and 50 cases of the natural delivery were selected from Hospital of Chengde Medical University as research subjects.All the recruited cases were selected with the newborns from April,2021 to April,2022.Defining the IVF-ET as the test group,while the natural delivery as the control group to compare and analyze the perinatal situations and the incidences of complications in both the groups.This study showed that the incidences of pregnancy-induced hypertension,diabetes,multiple pregnancy,premature delivery,and cesarean section in the test group were significantly(p<0.05)higher,than the control group.In addition,the incidences of neonatal respiratory distress syndrome(NRDS)and hyperbilirubinemia of newborns in the test group were statistical(p<0.05)higher,compared to the control group.In contrast,there are no statistically significant differences in terms of hypoglycemia,pneumonia,and neonatal asphyxia incidences between the two groups(p>0.05).Interestingly,there is a significant difference(p<0.05)in the incidences of neonatal cardiac anomalies in both groups,however,no significant differences(p>0.05)were observed in terms of birth defects including hypospadias,the cleft lip and palate,polydactyly,anal atresia,and esophageal atresia in both the groups.In summary,the test tube babies of IVF-ET are more susceptible to complications in their perinatal stage compared with natural delivery newborns,therefore,during the clinical development physicians should strengthen clinical attention and take proactive healthcare management,in order to maintain the health and life of the newborns.展开更多
The effects of heat-treatment on corrosion behavior of Mg-15Gd-2Zn-0.39Zr alloys were investigated through microstructure characterization, corrosion tests, and scanning Kelvin probe force microscope(SKPFM) analysis. ...The effects of heat-treatment on corrosion behavior of Mg-15Gd-2Zn-0.39Zr alloys were investigated through microstructure characterization, corrosion tests, and scanning Kelvin probe force microscope(SKPFM) analysis. In long-term corrosion experiments, the corrosion rates of Mg-Gd-Zn-Zr alloys were mainly determined by the effects of micro-galvanic corrosion. During heat-treatment, the β-(Mg,Zn)3Gd eutectic phase in as-cast alloys transformed into a long-period stacking ordered(LPSO) phase, coupled with the precipitation of small precipitates. As heat-treatment proceeded, the local potential and the volume fraction of the LPSO phases reduced gradually compared with the eutectic phase, which resulted in a remarkable decrease of the micro-galvanic effect between the second phase and Mg matrix. As a result, the corrosion resistance of heat-treated alloys improved significantly.展开更多
High entropy alloys(HEAs) have presented potential applications in nuclear power plants owing to their novel atomic structure based high irradiation resistance. However, understanding of He-ion irradiation of HEAs is ...High entropy alloys(HEAs) have presented potential applications in nuclear power plants owing to their novel atomic structure based high irradiation resistance. However, understanding of He-ion irradiation of HEAs is still lacking. In this work, we reveal He-ion irradiation resistance of HEA CrMnFeCoNi by comparison study with a pure Ni and a 304 stainless steel(304SS). It is found that the damage structure in the three materials can be characterized with He bubbles and stacking faults/stacking fault tetrahedrons((SFs/SFTs), which show a similar depth distribution after He-ion irradiation at both RT and 450℃.Although the He bubbles have a similar size about 2nm after irradiation at RT, the He bubble sizes of the HEA, 304SS, and Ni increase to 4.0±0.9,5.3±1.0 and 6.7 ±1.0 nm after irradiation at 450℃, respectively. Moreover, the density of SFs/SFTs displays in an order of Ni < 304 SS < HEA at both RT and 450℃.The He-ion irradiation at RT causes significant hardness enhancement for the three materials, however,compared to RT, after irradiation at 450℃, the Ni presents softening, while the 304SS, especially the HEA,shows further hardening. Thus, the HEA CrMnFeCoNi possesses the smallest He bubble size, the densest SFs/SFTs, and the highest hardening, indicating the best structural stability, as well as the best He-ion irradiation resistance, which can be attributed to its low mobility of He atoms and point defects.展开更多
In this study, a visualization-based experiment was performed to measure the motion of the nanowire under a magnetic field. A simulation method based on a multiple reference frame model(MRF model) was used to calculat...In this study, a visualization-based experiment was performed to measure the motion of the nanowire under a magnetic field. A simulation method based on a multiple reference frame model(MRF model) was used to calculate fluid torque. Here, it was validated with the experimental data and theoretical results. Fluid torque of steady rotated nanowire was simulated and compared using experiment and theoretical models. The unsteady rotated condition was studied using transient simulation to compare with theory and the results showed that the acceleration of nanowire did not affect the flow field, indicating that the theoretical models based on the steady condition were still valid. The influence of solid walls on nanowire rotation was also studied here. The results showed that if the nanowire was placed close to the wall, the viscous force of wall would increase the velocity gradient around the nanowire, causing higher torque predictions. The fluid torque decreased quickly when the vertical distance between nanowire and wall exceeded 5 times the diameter of the wire.展开更多
In this paper, a composite control scheme for macro-micro dual-drive positioning stage with high accel- eration and high precision is proposed. The objective of control is to improve the precision by reducing the infl...In this paper, a composite control scheme for macro-micro dual-drive positioning stage with high accel- eration and high precision is proposed. The objective of control is to improve the precision by reducing the influence of system vibration and external noise. The positioning stage is composed of voice coil motor (VCM) as macro driver and piezoelectric actuator (PEA) as micro driver. The precision of the macro drive positioning stage is improved by the com- bined PID control with adaptive Kalman filter (AKF). AKF is used to compensate VCM vibration (as the virtual noise) and the external noise. The control scheme of the micro drive positioning stage is presented as the integrated one with PID and intelligent adaptive inverse control approach to compensate the positioning error caused by macro drive positioning stage. A dynamic recurrent neural networks (DRNN) based inverse control approach is proposed to offset the hysteresis nonlinearity of PEA. Simulations show the positioning precision of macro-micro dual-drive stage is clearly improved via the proposed control scheme.展开更多
This work presents a cost-effective and environment-friendly form-stabilized phase change material(PCM)and corresponding solar thermal application in the tankless solar water heater(TSWH).Coconut shell charcoal(CSC)as...This work presents a cost-effective and environment-friendly form-stabilized phase change material(PCM)and corresponding solar thermal application in the tankless solar water heater(TSWH).Coconut shell charcoal(CSC)as supporting material was modified by moderate oxidant of H_(2)O_(2)with different concentrations,and then sta-bilized stearic acid(SA)to prepare composite PCMs through vacuum impregnation.It found that CSC support causes a 15.70%improvement of SA loadage after treated by 15%H_(2)O_(2)due to coefficient enhancement by phys-ical interaction and surface modification.The modified CSC 15 support appears more super macropores which contribute to the impregnation of SA than non-modified CSC 0 support verifying from SEM and BET results.And the content of oxygen functional groups was increased after oxidation modification,also motivating SA stabiliza-tion by hydrogen bond interaction in XPS analysis.FTIR results proved there is no chemical reaction happened between SA and CSC.Moreover,the latent heat and phase transition temperature of the as-prepared SA/CSC 15 composite are 76.69 J g^(−1)and 52.52℃,respectively.All composites exhibit excellent thermal stability under a working temperature of 180℃and form stability during phase change.Thermal energy storage-release test within 70℃presents the composite has fast heat transfer efficiency than pure SA.The composite filled in TSWH system has 0.75 W m^(−1)K^(−1)thermal conductivity which is 2.88 times higher than that of pure SA(0.26 W m^(−1)K−1).Besides,the TSWH system with a flow rate of 0.004 kg s^(−1)could heat water effectively after sunset and the energy obtained from the thermal storage system within 1830 s testing times is about 0.15 kW h.In all,SA/CSC composite with good physical-thermo properties has potential in thermal energy storage application,especially in solar energy storage.展开更多
It is challenging to match the mutual interactions between implant and host because the biomaterials usually cannot actively adjust their performance to the changing microenvironment.Surface potential is one of the cr...It is challenging to match the mutual interactions between implant and host because the biomaterials usually cannot actively adjust their performance to the changing microenvironment.Surface potential is one of the critical factors affecting the bioactivity of biomaterials,but it is difficult to be directly controlled in vivo.Magnetic stimulation has attracted much attention due to its deep penetrability,good reliability,and convenient operability.Here,titanium dioxide(TiO_(2))nanotubes and Terfenol‐D/P(VDF‐TrFE)composite film are prepared by anodic oxidation and solution casting methods on opposite sides of a titanium sheet,respectively.Terfenol‐D magnetostrictive microparticles deform under a magnetic field,generating surface potential on the P(VDF‐TrFE)piezoelectric matrix through magneto‐electric coupling.Correspondingly,equal opposite charges are induced on the surface of TiO_(2) nanotubes.Stem cells cultured on TiO_(2) nanotubes show that cell adhesion,proliferation,and differentiation abilities can be regulated by magnetic strength,which correlates with the absorption of charged proteins.Therefore,a cascade coupling of magnetic,mechanical,electric,biochemical,and cellular effects is established.This work demonstrates the feasibility of regulating the bioactivity of biomaterials in vivo through a magnetic field.展开更多
In this paper, we present the full state hybrid projective synchronization (FSHPS) of nonautonomous chaotic systems. Based on Lyapunov stability theory, we study the FSHPS of the nonautonomous system. Numerical simula...In this paper, we present the full state hybrid projective synchronization (FSHPS) of nonautonomous chaotic systems. Based on Lyapunov stability theory, we study the FSHPS of the nonautonomous system. Numerical simulations are presented to verify that the controller is effective and feasible.展开更多
基金supported by the Project of the State Grid Corporation of China in 2022(No.5700-201941501A-0-0-00)the National Natural Science Foundation of China(No.U21B2031).
文摘With the rapid development and popularization of artificial intelligence technology,convolutional neural network(CNN)is applied in many fields,and begins to replace most traditional algorithms and gradually deploys to terminal devices.However,the huge data movement and computational complexity of CNN bring huge power consumption and performance challenges to the hardware,which hinders the application of CNN in embedded devices such as smartphones and smart cars.This paper implements a convolutional neural network accelerator based on Winograd convolution algorithm on field-programmable gate array(FPGA).Firstly,a convolution kernel decomposition method for Winograd convolution is proposed.The convolution kernel larger than 3×3 is divided into multiple 3×3 convolution kernels for convolution operation,and the unsynchronized long convolution operation is processed.Then,we design Winograd convolution array and use configurable multiplier to flexibly realize multiplication for data with different accuracy.Experimental results on VGG16 and AlexNet network show that our accelerator has the most energy efficient and 101 times that of the CPU,5.8 times that of the GPU.At the same time,it has higher energy efficiency than other convolutional neural network accelerators.
基金This study was funded by Natural Science Foundation of China(No.31670340 and No.31970357)Bio-Innovation Center of DR PLANT,Kunming Institute of Botany,Chinese Academy of Sciences.
文摘The Naxi of Northwest Yunnan,China use medicinal plants to treat skin conditions related to traditional lifestyles in extreme environments.However,modernization endangers both the medicinal plants used to treat skin conditions and traditional knowledge.Therefore,investigation and documentation of the medicinal plants used and associated traditional knowledge is necessary.In this study,we conducted an ethnobotanical survey in 12 Naxi communities in Northwest Yunnan.For this purpose,we used semistructured surveys to interview 840 informants from Naxi communities.We used informant consensus factor and use frequency as quantitative indices to evaluate the importance of medicinal plant species.A total of 161 medicinal plant species belonging to 69 families were documented.The highest informant consensus factor(ICF)values were recorded for skin nourishing(ICF?0.849),frostbite and chapped skin(ICF?0.833).These skin treatments are highly related to the environment and lifestyle of Naxi communities.The main active compounds of plants used to treat skin conditions in Naxi communities are known to have skin-treating properties.This study reveals that the skin conditions treated by the Naxi are associated with traditional medicine culture and social economic development.In addition,this study uses ethnobotanical indices to explain how skin condition treatments are linked to the natural environment of Naxi communities.
文摘The concept of eco-civilisation refers to the need for human affairs to be contained within the limits set by nature.Plants play such fundamental roles in the functioning of ecosystems and economies that due attention must be given to them for eco-civilisation to be achieved.Species are the basic functional units of the plant world and,taking a long term perspective,their conservation with their genetic diversity should be a primary objective in eco-civilisation construction.However,standard procedures used for plant conservation have met with only limited success.Therefore,plant conservationists need social allies to boost their efforts-referring to elements of society whose primary interests in eco-civilisation construction are different,but whose efforts,if successful,will bring benefits to plant conservation too.Potential allies can be identified using an ecosystem system services framework showing how benefits received from the delivery of ecosystem services overlap with those that favour conservation of plant diversity.The concept of eco-civilisation was adopted officially in China in 2014 as a principle guiding its future development.A project at Ludian,Yunnan Province,is used to show the relationships between an ecosystem services framework and a conservation initiative.
基金This work is supported by the Natural Science Foundation of Shandong Province(ZR2017MF072)and HIT Graduate Teaching Innovation Project(JGYJ-2019039).
文摘In this paper,a mode-locked Ytterbiumdoped fiber laser based on nonlinear optical loop mirror(NOLM)is proposed.The laser generates a wide-spectrum dissipative soliton resonance modelocked pulse with strong stimulated Raman scattering.The fiber laser is pumped forward,and the fiber ring cavity contains double-cladding Yb-doped fiber,output coupler,polarization controller,polarization independent isolator and other elements.NOLM is connected with the ring cavity by through a 3dB beam splitter and 25m single-mode fiber.The total length of the eight-shape cavity laser is about 60meters.By adjusting the intra-cavity polarization controller,a stable dissipative soliton resonance mode-locked spike pulse can be achieved.The repetition frequency of the pulse train is 3.44MHz,which is consistent with the cavity length.The 3dB bandwidth of the spectrum reaches 70.6nm,and the 10dB bandwidth is close to 147.11nm.In this experiment,dissipative soliton resonance mode-locked pulses with wide spectrum and high pulse energy are realized by a traditional modelocking method,which has wide application in many fields such as laser spectral detection and terahertz wave generation.
文摘This study was conducted to compare the perinatal complications for newborns by In vitro fertilization with embryo transfer(IVF-ET)and natural delivery.Respectively 50 cases of the IVF-ET and 50 cases of the natural delivery were selected from Hospital of Chengde Medical University as research subjects.All the recruited cases were selected with the newborns from April,2021 to April,2022.Defining the IVF-ET as the test group,while the natural delivery as the control group to compare and analyze the perinatal situations and the incidences of complications in both the groups.This study showed that the incidences of pregnancy-induced hypertension,diabetes,multiple pregnancy,premature delivery,and cesarean section in the test group were significantly(p<0.05)higher,than the control group.In addition,the incidences of neonatal respiratory distress syndrome(NRDS)and hyperbilirubinemia of newborns in the test group were statistical(p<0.05)higher,compared to the control group.In contrast,there are no statistically significant differences in terms of hypoglycemia,pneumonia,and neonatal asphyxia incidences between the two groups(p>0.05).Interestingly,there is a significant difference(p<0.05)in the incidences of neonatal cardiac anomalies in both groups,however,no significant differences(p>0.05)were observed in terms of birth defects including hypospadias,the cleft lip and palate,polydactyly,anal atresia,and esophageal atresia in both the groups.In summary,the test tube babies of IVF-ET are more susceptible to complications in their perinatal stage compared with natural delivery newborns,therefore,during the clinical development physicians should strengthen clinical attention and take proactive healthcare management,in order to maintain the health and life of the newborns.
基金supported by the National Key R&D Program of China(2022YFC2105501)the National Natural Science Foundation of China(32202720)+2 种基金the Agricultural Science and Technology Innovation Program(CAAS-ZDRW202304 and CAAS-ASTIPG2022-IFST-07)the Central Public-interest Scientific Institution Basal Research Fund(1610392020001)the Agricultural Science and Technology Innovation Program(ASTIP)。
基金financial support from the National Natural Science Foundation of China (Nos. 51531007 and 51771050)the National program for the Young Top-notch Professionalsthe Fundamental Research Funds for the Central Universities (N170205002)
文摘The effects of heat-treatment on corrosion behavior of Mg-15Gd-2Zn-0.39Zr alloys were investigated through microstructure characterization, corrosion tests, and scanning Kelvin probe force microscope(SKPFM) analysis. In long-term corrosion experiments, the corrosion rates of Mg-Gd-Zn-Zr alloys were mainly determined by the effects of micro-galvanic corrosion. During heat-treatment, the β-(Mg,Zn)3Gd eutectic phase in as-cast alloys transformed into a long-period stacking ordered(LPSO) phase, coupled with the precipitation of small precipitates. As heat-treatment proceeded, the local potential and the volume fraction of the LPSO phases reduced gradually compared with the eutectic phase, which resulted in a remarkable decrease of the micro-galvanic effect between the second phase and Mg matrix. As a result, the corrosion resistance of heat-treated alloys improved significantly.
基金supported financially by the "Hundred Talents Project" of Chinese Academy of Sciencesthe "Thousand Youth Talents Plan" of China+1 种基金the National Natural Science Foundation of China (Nos. 51401208 and 51771201)the Shenyang National Laboratory for Materials Science (No. 2017RP17)
文摘High entropy alloys(HEAs) have presented potential applications in nuclear power plants owing to their novel atomic structure based high irradiation resistance. However, understanding of He-ion irradiation of HEAs is still lacking. In this work, we reveal He-ion irradiation resistance of HEA CrMnFeCoNi by comparison study with a pure Ni and a 304 stainless steel(304SS). It is found that the damage structure in the three materials can be characterized with He bubbles and stacking faults/stacking fault tetrahedrons((SFs/SFTs), which show a similar depth distribution after He-ion irradiation at both RT and 450℃.Although the He bubbles have a similar size about 2nm after irradiation at RT, the He bubble sizes of the HEA, 304SS, and Ni increase to 4.0±0.9,5.3±1.0 and 6.7 ±1.0 nm after irradiation at 450℃, respectively. Moreover, the density of SFs/SFTs displays in an order of Ni < 304 SS < HEA at both RT and 450℃.The He-ion irradiation at RT causes significant hardness enhancement for the three materials, however,compared to RT, after irradiation at 450℃, the Ni presents softening, while the 304SS, especially the HEA,shows further hardening. Thus, the HEA CrMnFeCoNi possesses the smallest He bubble size, the densest SFs/SFTs, and the highest hardening, indicating the best structural stability, as well as the best He-ion irradiation resistance, which can be attributed to its low mobility of He atoms and point defects.
基金supported by the National Natural Science Foundation of China (Grant No. 50876006)the Fundamental Research Funds for the Central Universities (Grant No. 2011YJS053)
文摘In this study, a visualization-based experiment was performed to measure the motion of the nanowire under a magnetic field. A simulation method based on a multiple reference frame model(MRF model) was used to calculate fluid torque. Here, it was validated with the experimental data and theoretical results. Fluid torque of steady rotated nanowire was simulated and compared using experiment and theoretical models. The unsteady rotated condition was studied using transient simulation to compare with theory and the results showed that the acceleration of nanowire did not affect the flow field, indicating that the theoretical models based on the steady condition were still valid. The influence of solid walls on nanowire rotation was also studied here. The results showed that if the nanowire was placed close to the wall, the viscous force of wall would increase the velocity gradient around the nanowire, causing higher torque predictions. The fluid torque decreased quickly when the vertical distance between nanowire and wall exceeded 5 times the diameter of the wire.
基金partly supported by the National Natural Science Foundation of China(No.61174047)the School Basic Foundation of Northwestern Polytechnical University(No.GCKYI006)the Fundamental Research Funds for the Central Universities(No.HEUCFR1214)
文摘In this paper, a composite control scheme for macro-micro dual-drive positioning stage with high accel- eration and high precision is proposed. The objective of control is to improve the precision by reducing the influence of system vibration and external noise. The positioning stage is composed of voice coil motor (VCM) as macro driver and piezoelectric actuator (PEA) as micro driver. The precision of the macro drive positioning stage is improved by the com- bined PID control with adaptive Kalman filter (AKF). AKF is used to compensate VCM vibration (as the virtual noise) and the external noise. The control scheme of the micro drive positioning stage is presented as the integrated one with PID and intelligent adaptive inverse control approach to compensate the positioning error caused by macro drive positioning stage. A dynamic recurrent neural networks (DRNN) based inverse control approach is proposed to offset the hysteresis nonlinearity of PEA. Simulations show the positioning precision of macro-micro dual-drive stage is clearly improved via the proposed control scheme.
基金This work was supported by the National Natural Science Founda-tion of China(51874047,51504041)the Training Program for Excel-lent Young Innovators of Changsha(kq1802007)+2 种基金the Fund for Univer-sity Young Core Instructors of Hunan Provincethe Outstanding Youth Project of Hunan Provincial Department of Education(18B148)and the Hunan Province 2011 Collaborative Innovation Center of Clean Energy and Smart Grid.
文摘This work presents a cost-effective and environment-friendly form-stabilized phase change material(PCM)and corresponding solar thermal application in the tankless solar water heater(TSWH).Coconut shell charcoal(CSC)as supporting material was modified by moderate oxidant of H_(2)O_(2)with different concentrations,and then sta-bilized stearic acid(SA)to prepare composite PCMs through vacuum impregnation.It found that CSC support causes a 15.70%improvement of SA loadage after treated by 15%H_(2)O_(2)due to coefficient enhancement by phys-ical interaction and surface modification.The modified CSC 15 support appears more super macropores which contribute to the impregnation of SA than non-modified CSC 0 support verifying from SEM and BET results.And the content of oxygen functional groups was increased after oxidation modification,also motivating SA stabiliza-tion by hydrogen bond interaction in XPS analysis.FTIR results proved there is no chemical reaction happened between SA and CSC.Moreover,the latent heat and phase transition temperature of the as-prepared SA/CSC 15 composite are 76.69 J g^(−1)and 52.52℃,respectively.All composites exhibit excellent thermal stability under a working temperature of 180℃and form stability during phase change.Thermal energy storage-release test within 70℃presents the composite has fast heat transfer efficiency than pure SA.The composite filled in TSWH system has 0.75 W m^(−1)K^(−1)thermal conductivity which is 2.88 times higher than that of pure SA(0.26 W m^(−1)K−1).Besides,the TSWH system with a flow rate of 0.004 kg s^(−1)could heat water effectively after sunset and the energy obtained from the thermal storage system within 1830 s testing times is about 0.15 kW h.In all,SA/CSC composite with good physical-thermo properties has potential in thermal energy storage application,especially in solar energy storage.
基金Guangdong Basic and Applied Basic Research Foundation,Grant/Award Numbers:2021B1515120019,2019A1515011891,2015A030312004Science and Technology Projects in Guangzhou,Grant/Award Number:202102020644Opening Project of Guangdong Provincial Key Laboratory of Technique and Equipment for Macromolecular Advanced Manufacturing,Grant/Award Number:2019kfkt01。
文摘It is challenging to match the mutual interactions between implant and host because the biomaterials usually cannot actively adjust their performance to the changing microenvironment.Surface potential is one of the critical factors affecting the bioactivity of biomaterials,but it is difficult to be directly controlled in vivo.Magnetic stimulation has attracted much attention due to its deep penetrability,good reliability,and convenient operability.Here,titanium dioxide(TiO_(2))nanotubes and Terfenol‐D/P(VDF‐TrFE)composite film are prepared by anodic oxidation and solution casting methods on opposite sides of a titanium sheet,respectively.Terfenol‐D magnetostrictive microparticles deform under a magnetic field,generating surface potential on the P(VDF‐TrFE)piezoelectric matrix through magneto‐electric coupling.Correspondingly,equal opposite charges are induced on the surface of TiO_(2) nanotubes.Stem cells cultured on TiO_(2) nanotubes show that cell adhesion,proliferation,and differentiation abilities can be regulated by magnetic strength,which correlates with the absorption of charged proteins.Therefore,a cascade coupling of magnetic,mechanical,electric,biochemical,and cellular effects is established.This work demonstrates the feasibility of regulating the bioactivity of biomaterials in vivo through a magnetic field.
基金supported by the Gansu Provincial Education Department Foundation 0808-04Scientific Research Foundations of Tianshui Normal University TSA0938
文摘In this paper, we present the full state hybrid projective synchronization (FSHPS) of nonautonomous chaotic systems. Based on Lyapunov stability theory, we study the FSHPS of the nonautonomous system. Numerical simulations are presented to verify that the controller is effective and feasible.