Low power efficiency is a deficiency in traditional Orthogonal Frequency Division Multiplexing （OFDM） systems. To counter this problem, a new wireless transmission technology based on Zero-Padding Carrier Interferom...Low power efficiency is a deficiency in traditional Orthogonal Frequency Division Multiplexing （OFDM） systems. To counter this problem, a new wireless transmission technology based on Zero-Padding Carrier Interferometry OFDM （ZP-CI/OFDM） is proposed. In a ZP-CI/OFDM system, transmission symbols are spread to all OFDM subcarriers via carrier interferometry codes. This reduces the Peak-to-Average Power Ratio （PAPR） that traditional OFDM suffers and also exploits frequency diversity gain. By zero-padding at the transmitter, advanced receiver technologies can be adopted for ZP-CI/OFDM so that frequency diversity gain can be further utilized and the power efficiency of the system is improved.展开更多
With the continuous improvement of photovoltaic efficiency in the organic photovoltaic(OPV),interface engineering has emerged as a pivotal issue in their practical deployment.Currently,the robust crystallinity of smal...With the continuous improvement of photovoltaic efficiency in the organic photovoltaic(OPV),interface engineering has emerged as a pivotal issue in their practical deployment.Currently,the robust crystallinity of small molecule electron transport layers(ETLs)and the poor film-forming abilities of conjugated polymer ETLs are a huge obstacle in this field.Herein,an innovative and efficient nonconjugated polymer ETL,namely PNDI-SO,which contains polar cationic segments for solubility and conjugated units for efficient charge transport in stable OPV cells,is reported.Endowed with suitable energy levels and excellent electron extraction capabilities,PNDI-SO-based OPV cells attain a power conversion efficiency(PCE)of 18.54%.Furthermore,compared with conventional OPV cells utilizing PFN-Br or PDINN,PNDI-SO substantially enhances long-term stability under continuous illumination,evidenced by a T80 lifetime(signifying retention of 80% of initial performance)exceeding 1250 h.Notably,through scanning electron microscope,we verified that PNDI-SO achieves a harmonious balance between film-forming ability and charge transport properties for ETL,enabling the blade-coating OPV based on PBDB-TF:BTP-eC9 to achieve a PCE of 17.47%.These results suggest the potential of PNDI-SO as a promising interface material for industrial printing applications in OPV fabrication.展开更多
This study investigates the Maximum Power Point Tracking(MPPT)control method of offshore windphotovoltaic hybrid power generation system with offshore crane-assisted.A new algorithm of Global Fast Integral Sliding Mod...This study investigates the Maximum Power Point Tracking(MPPT)control method of offshore windphotovoltaic hybrid power generation system with offshore crane-assisted.A new algorithm of Global Fast Integral Sliding Mode Control(GFISMC)is proposed based on the tip speed ratio method and sliding mode control.The algorithm uses fast integral sliding mode surface and fuzzy fast switching control items to ensure that the offshore wind power generation system can track the maximum power point quickly and with low jitter.An offshore wind power generation system model is presented to verify the algorithm effect.An offshore off-grid wind-solar hybrid power generation systemis built in MATLAB/Simulink.Compared with other MPPT algorithms,this study has specific quantitative improvements in terms of convergence speed,tracking accuracy or computational efficiency.Finally,the improved algorithm is further analyzed and carried out by using Yuankuan Energy’s ModelingTech semi-physical simulation platform.The results verify the feasibility and effectiveness of the improved algorithm in the offshore wind-solar hybrid power generation system.展开更多
A low power high performance Delta-Sigma modulator for portable measurement applications is presented. To reduce power consumption while maintaining high performance, a fully feedforward architecture with a comprehens...A low power high performance Delta-Sigma modulator for portable measurement applications is presented. To reduce power consumption while maintaining high performance, a fully feedforward architecture with a comprehensive system-level design is implemented. As a key building block, a novel power efficient current mirror operational transconductance amplifier (OTA) with a fast-settling less-error switched-capacitor common-mode feedback (SC CMFB) circuit is introduced, and the effects of both gain nonlinearity and 1/f noise of OTA are discussed. A new method to determine the voltage gain of an OTA is also proposed. The bottom terminal parasitic effect of poly-insulator-poly (PIP) capacitors is considered. About an extra 20% of capacitance is added to the total capacitance load. A power and area efficient resonator is adopted to realize a coefficient of 1/90 for 50% power and 75% area reduction compared with conventional designs. The chip is implemented in a low cost 0.35 μm complementary metal oxide semiconductor (CMOS) process. The total power consumption is 20 μW with a 1.5 V supply, and the measured dynamic range (DR) is 95 dB over a 1 kHz bandwidth. Experimental results show that a high figure-of-merit (FOM) is achieved for the designed modulator in comparison with those from the literature.展开更多
The analysis and design of a semi-passive radio frequency identification（RFID） tag is presented.By studying the power transmission link of the backscatter RFID system and exploiting a power conversion efficiency mod...The analysis and design of a semi-passive radio frequency identification（RFID） tag is presented.By studying the power transmission link of the backscatter RFID system and exploiting a power conversion efficiency model for a multi-stage AC-DC charge pump,the calculation method for semi-passive tag＇s read range is proposed.According to different read range limitation factors,an intuitive way to define the specifications of tag＇s power budget and backscatter modulation index is given.A test chip is implemented in SMIC 0.18μm standard CMOS technology under the guidance of theoretical analysis.The main building blocks are the threshold compensated charge pump and low power wake-up circuit using the power triggering wake-up mode.The proposed semi-passive tag is fully compatible to EPC C1G2 standard.It has a compact chip size of 0.54 mm^2,and is adaptable to batteries with a 1.2 to 2.4 V output voltage.展开更多
A polymeric nanopore membrane with selective ionic transport has been proposed as a potential device to convert the chemical potential energy in salinity gradients to electrical power. However, its energy conversion e...A polymeric nanopore membrane with selective ionic transport has been proposed as a potential device to convert the chemical potential energy in salinity gradients to electrical power. However, its energy conversion efficiency and power density are often limited due to the challenge in reliably controlling the size of the nanopores with the conventional chemical etching method. Here we report that without chemical etching, polyimide （PI） membranes irradiated with GeV heavy ions have negatively charged nanopores, showing nearly perfect selectivity for cations over anions, and they can generate electrical power from salinity gradients. We further demonstrate that the power generation efficiency of the PI membrane approaches the theoretical limit, and the maximum power density reaches 130m W/m2 with a modified etching method, outperforming the previous energy conversion device that was made of polymeric nanopore membranes.展开更多
Considering that perfect channel state information(CSI) is difficult to obtain in practice,energy efficiency(EE) for distributed antenna systems(DAS) based on imperfect CSI and antennas selection is investigated in Ra...Considering that perfect channel state information(CSI) is difficult to obtain in practice,energy efficiency(EE) for distributed antenna systems(DAS) based on imperfect CSI and antennas selection is investigated in Rayleigh fading channel.A novel EE that is defined as the average transmission rate divided by the total consumed power is introduced.In accordance with this definition,an adaptive power allocation(PA) scheme for DAS is proposed to maximize the EE under the maximum transmit power constraint.The solution of PA in the constrained EE optimization does exist and is unique.A practical iterative algorithm with Newton method is presented to obtain the solution of PA.The proposed scheme includes the one under perfect CSI as a special case,and it only needs large scale and statistical information.As a result,the scheme has low overhead and good robustness.The theoretical EE is also derived for performance evaluation,and simulation result shows the validity of the theoretical analysis.Moreover,EE can be enhanced by decreasing the estimation error and/or path loss exponents.展开更多
All polymer solar cells(all-PSCs)promise mechanically-flexible and morphologically-stable organic photovoltaics and have aroused increased interests very recently.However,due to their disorderly conformation structure...All polymer solar cells(all-PSCs)promise mechanically-flexible and morphologically-stable organic photovoltaics and have aroused increased interests very recently.However,due to their disorderly conformation structures within the photoactive film,inefficient charge generation and carrier transport are observed which lead to inferior photovoltaic performance compared to smaller molecular acceptor-based photovoltaics.Here,by diluting PM6 with a cutting-edge polymeric acceptor PY-IT and diluting PY-IT with PM6 or D18,donor-dominating or acceptor-dominating heterojunctions were prepared.Synchrotron X-ray and multiple spectrometer techniques reveal that the diluted heterojunctions receive increased structural order,translating to enhanced carrier mobility,improved exciton diffusion length,and suppressed non-radiative recombination loss during the power conversion.As the results,the corresponding PM6+1%PY-IT/PY-IT+1%D18 and PM6+1%PY-IT/PY-IT+1%PM6 devices fabricated by layer-by-layer deposition received superior power conversion efficiency(PCE)of 19.4%and 18.8%respectively,along with enhanced operational lifetimes in air,outperforming the PCE of 17.5%in the PM6/PY-IT reference device.展开更多
Due to a series of challenges such as low-orbit maintenance of satellites, the air-breathing electric propulsion has got widespread attention. Commonly, the radio frequency ion thruster is favored by low-orbit mission...Due to a series of challenges such as low-orbit maintenance of satellites, the air-breathing electric propulsion has got widespread attention. Commonly, the radio frequency ion thruster is favored by low-orbit missions due to its high specific impulse and efficiency. In this paper, the power transfer efficiency of the radio frequency ion thruster with different gas compositions is studied experimentally, which is obtained by measuring the radio frequency power and current of the antenna coil with and without discharge operation. The results show that increasing the turns of antenna coils can effectively improve the radio frequency power transfer efficiency, which is due to the improvement of Q factor. In pure N_2 discharge,with the increase of radio frequency power, the radio frequency power transfer efficiency first rises rapidly and then exhibits a less steep increasing trend. The radio frequency power transfer efficiency increases with the increase of gas pressure at relatively high power, while declines rapidly at relatively low power. In N_(2)/O_(2) discharge, increasing the N_(2) content at high power can improve the radio frequency power transfer efficiency, but the opposite was observed at low power. In order to give a better understanding of these trends, an analytic solution in limit cases is utilized, and a Langmuir probe was employed to measure the electron density. It is found that the evolution of radio frequency power transfer efficiency can be well explained by the variation of plasma resistance, which is related to the electron density and the effective electron collision frequency.展开更多
Self-assembled monolayers(SAMs)have recently emerged as excellent hole transport materials in inverted perovskite solar cells(PSCs)owing to their ability to minimize parasitic absorption,regulate energy level alignmen...Self-assembled monolayers(SAMs)have recently emerged as excellent hole transport materials in inverted perovskite solar cells(PSCs)owing to their ability to minimize parasitic absorption,regulate energy level alignment,and passivate perovskite defects.Herein,we design and synthesize a novel dimethyl acridinebased SAM,[2-(9,10-dihydro-9,9-dimethylacridine-10-yl)ethyl]phosphonic acid(2PADmA),and employ it as a hole-transporting layer in inverted PSCs.Experimental results show that the 2PADmA SAM can modulate perovskite crystallization,facilitate carrier transport,passivate perovskite defects,and reduce nonradiative recombination.Consequently,the 2PADmA-based device achieves an enhanced power conversion efficiency(PCE)of 24.01%and an improved fill factor(FF)of 83.92%compared to the commonly reported[2-(9H-carbazol-9-yl)ethyl]phosphonic acid(2PACz)-based control device with a PCE of 22.32%and FF of 78.42%,while both devices exhibit comparable open-circuit voltage and short-circuit current density.In addition,2PADmA-based devices exhibit outstanding dark storage and thermal stabilities,retaining approximately~98%and 87%of their initial PCEs after 1080 h of dark storage and 400 h of heating at 85°C,respectively,both considerably superior to the control device.展开更多
With the accelerated growth of the Internet of Things(IoT),real-time data processing on edge devices is increasingly important for reducing overhead and enhancing security by keeping sensitive data local.Since these d...With the accelerated growth of the Internet of Things(IoT),real-time data processing on edge devices is increasingly important for reducing overhead and enhancing security by keeping sensitive data local.Since these devices often handle personal information under limited resources,cryptographic algorithms must be executed efficiently.Their computational characteristics strongly affect system performance,making it necessary to analyze resource impact and predict usage under diverse configurations.In this paper,we analyze the phase-level resource usage of AES variants,ChaCha20,ECC,and RSA on an edge device and develop a prediction model.We apply these algorithms under varying parallelism levels and execution strategies across key generation,encryption,and decryption phases.Based on the analysis,we train a unified Random Forest model using execution context and temporal features,achieving R2 values up to 0.994 for power and 0.988 for temperature.Furthermore,the model maintains practical predictive performance even for cryptographic algorithms not included during training,demonstrating its ability to generalize across distinct computational characteristics.Our proposed approach reveals how execution characteristics and resource usage interacts,supporting proactive resource planning and efficient deployment of cryptographic workloads on edge devices.As our approach is grounded in phase-level computational characteristics rather than in any single algorithm,it provides generalizable insights that can be extended to a broader range of cryptographic algorithms that exhibit comparable phase-level execution patterns and to heterogeneous edge architectures.展开更多
In recent years, the research advancements have high-lighted the critical role of the A-site cation in determining the optoelectronic and physicochemical properties of organicinorganic lead halide perovskites. Mixed-c...In recent years, the research advancements have high-lighted the critical role of the A-site cation in determining the optoelectronic and physicochemical properties of organicinorganic lead halide perovskites. Mixed-cation perovskites(MCPs) have been extensively used as absorber thin films in perovskite solar cells(PSCs), achieving high power conversion efficiencies(PCE) over 26%^([1, 2]).展开更多
Trap-assisted charge recombination is one of the primary limitationsof restricting the performance of organic solar cells. However, effectivelyreducing the presence of traps in the photoactive layer remains challengin...Trap-assisted charge recombination is one of the primary limitationsof restricting the performance of organic solar cells. However, effectivelyreducing the presence of traps in the photoactive layer remains challenging.Herein, wide bandgap polymer donor PTzBI-dF is demonstrated as an effectivemodulator for enhancing the crystallinity of the bulk heterojunction active layerscomposed of D18 derivatives blended with Y6, leading to dense and orderedmolecular packings, and thus, improves photoluminescence quenching properties.As a result, the photovoltaic devices exhibit reduced trap-assisted charge recombinationlosses, achieving an optimized power conversion efficiency of over 19%.Besides the efficiency enhancement, the devices comprised of PTzBI-dF as athird component simultaneously attain decreased current leakage, improved chargecarrier mobilities, and suppressed bimolecular charge recombination, leading toreduced energy losses. The advanced crystalline structures induced by PTzBI-dFand its characteristics, such as well-aligned energy level, and complementaryabsorption spectra, are ascribed to the promising performance improvements.Our findings suggest that donor phase engineering is a feasible approach to tuning the molecular packings in the active layer, providingguidelines for designing effective morphology modulators for high-performance organic solar cells.展开更多
Strategic design of solid additives for regulating molecular aggregation and crystallinity in organic photovoltaic systems is crucial for enhancing device efficiency and stability.Herein,we introduce 3,5-dibromoanisol...Strategic design of solid additives for regulating molecular aggregation and crystallinity in organic photovoltaic systems is crucial for enhancing device efficiency and stability.Herein,we introduce 3,5-dibromoanisole(DBA),a volatile solid additive synergistically integrating halogen and alkoxy functionalities,to optimize the PM6:Y6 active layer.DBA simultaneously interacts with both PM6 and Y6,promoting face-on molecular orientation and fibrillar network formation.Consequently,DBA-treated devices achieve a power conversion efficiency(PCE)of 18.34%,with a short-circuit current density(J_(SC))of 28.24 mA·cm^(–2) and a fill factor(FF)of 78.6%,surpassing the control device(PCE=17.13%).Notably,the DBA additive exhibits exceptional stability and demonstrates broad applicability across multiple material systems.This study establishes a universal framework for designing multifunctional solid additives,paving the way for scalable,high-efficiency organic solar cells(OSCs).展开更多
The Shockley-Queisser(S-Q)model sets a theoretical limit on the power conversion efficiency(PCE)of single-junction solar cells at around 33%.Recently,a PCE of 50%-60%was achieved for the first time in n-type singlejun...The Shockley-Queisser(S-Q)model sets a theoretical limit on the power conversion efficiency(PCE)of single-junction solar cells at around 33%.Recently,a PCE of 50%-60%was achieved for the first time in n-type singlejunction Si solar cells by inhibiting light conversion to heat at low temperatures.Understanding these new observations opens tremendous opportunities for designing solar cells with even higher PCE to provide efficient and powerful energy sources for cryogenic devices and outer and deep space explorations.展开更多
The rapid advancement of metal halide perovskites can be attributed to their exceptional optoelectronic properties and facile solution processing technique.Noteworthy strides have been achieved in the realm of perovsk...The rapid advancement of metal halide perovskites can be attributed to their exceptional optoelectronic properties and facile solution processing technique.Noteworthy strides have been achieved in the realm of perovskite solar cells(PSCs),with a certified power conversion efficiency(PCE)escalating to 26.7%over the course of a decade,positioning them as promising contenders for next-generation photovoltaic technologies[1].However,the formation of crystal defects,including anion/cation vacancies,Pb–I antisite defects,and uncoordinated Pb^(2+),along the surface and grain boundaries(GBs)of perovskite layers during the solution processing stage poses a significant challenge,compromising the photoelectric performance and stability of PSCs.展开更多
In this research highlight,recent significant advances with hot-assisted blade-coating or air knife-assisted blade-coating of different perovskite compositions with bandgaps ranging from 1.3 eV to 1.9 eV(i.e.widebandg...In this research highlight,recent significant advances with hot-assisted blade-coating or air knife-assisted blade-coating of different perovskite compositions with bandgaps ranging from 1.3 eV to 1.9 eV(i.e.widebandgap or small-bandgap perovskites with mixed cations and anions,2D/3D perovskites,Pb/Sn binary perovskites,and all-inorganic perovskites)for single-junction or tandem PSCs are discussed,with an emphasis on elucidating the distinct ink formulation engineering strategies,crystal growth mechanisms,crystallization kinetics,and optoelectronic properties of the different perovskite compositions.展开更多
Current high power load simulators are generally incapable of obtaining both high loading performance and high energy efficiency. Simulators with high energy efficiency are used to simulate static-state load, and thos...Current high power load simulators are generally incapable of obtaining both high loading performance and high energy efficiency. Simulators with high energy efficiency are used to simulate static-state load, and those with high dynamic performance typically have low energy efficiency. In this paper, the variants of secondary control（VSC） with power recovery are developed to solve this problem for loading hydraulic driving devices that operate under variable pressure, unlike classical secondary control（CSC） that operates in constant pressure network. Hydrostatic secondary control units are used as the loading components, by which the absorbed mechanical power from the tested device is converted into hydraulic power and then fed back into the tested system through 4 types of feedback passages（FPs）. The loading subsystem can operate in constant pressure network, controlled variable pressure network, or the same variable pressure network as that of the tested device by using different FPs. The 4 types of systems are defined, and their key techniques are analyzed, including work principle, simulating the work state of original tested device, static operation points, loading performance, energy efficiency, and control strategy, etc. The important technical merits of the 4 schemes are compared, and 3 of the schemes are selected, designed, simulated using AMESim and evaluated. The researching results show that the investigated systems can simulate the given loads effectively, realize the work conditions of the tested device, and furthermore attain a high power recovery efficiency that ranges from 0.54 to 0.85, even though the 3 schemes have different loading performances and energy efficiencies. This paper proposes several loading schemes that can achieve both high dynamic performance and high power recovery efficiency.展开更多
The rational design of polymer acceptors with strong and broad absorption is critical to improve photovoltaic performance.In this work,a new polymer acceptor PY9-T based on heptacyclic benzotriazole(Y9-C16)as a buildi...The rational design of polymer acceptors with strong and broad absorption is critical to improve photovoltaic performance.In this work,a new polymer acceptor PY9-T based on heptacyclic benzotriazole(Y9-C16)as a building block and thiophene unit as the linking unit was synthesized,which exhibited a low bandgap(1.37 eV)and a high extinction coefficient of the neat film(1.44×10^(5) cm^(−1)).When PY9-T was blended with the wide bandgap polymer donor PBDB-T,the all-polymer solar cells(APSCs)showed a high power conversion efficiency(PCE)of 10.45%with both high open circuit voltage of 0.881 V and short-circuit current density of 19.82 mA/cm^(2).In addition,APSCs based on PY9-T show good thermal stability,as evidenced by slight changes morphologies when annealed at 100℃.These results suggest that Y9-C16 provides a new building block to develop efficient and stable polymer acceptors.展开更多
The self-assembly process for compatible functional layers of devices is a simple,feasible,and energy-saving strategy.In mesoporous perovskite solar cells(PSCs),compact and scaffold TiO_(2) films generally function as...The self-assembly process for compatible functional layers of devices is a simple,feasible,and energy-saving strategy.In mesoporous perovskite solar cells(PSCs),compact and scaffold TiO_(2) films generally function as the hole-blocking and electron-transporting layers,respectively.However,both of these layers are usually generated through a high-temperature annealing process.Here,we deposited TiO_(2) compact films through a room-temperature self-assembly process as effective hole-blocking layers for PSCs.The thickness of TiO_(2) compact films can be easily controlled by the deposition time.Through the optimization of TiO_(2) compact films(80 nm),the power conversion efficiency(PCE)of mesoporous PSCs without and with hole conductor layers increases up to 10.66%and 17.95%,respectively.Notably,an all-low-temperature planar PSC with the self-assembled TiO_(2) layer exhibits a PCE of 16.41%.展开更多
基金supported by the National Natural Science Foundation of China under Grant No.61071102
文摘Low power efficiency is a deficiency in traditional Orthogonal Frequency Division Multiplexing （OFDM） systems. To counter this problem, a new wireless transmission technology based on Zero-Padding Carrier Interferometry OFDM （ZP-CI/OFDM） is proposed. In a ZP-CI/OFDM system, transmission symbols are spread to all OFDM subcarriers via carrier interferometry codes. This reduces the Peak-to-Average Power Ratio （PAPR） that traditional OFDM suffers and also exploits frequency diversity gain. By zero-padding at the transmitter, advanced receiver technologies can be adopted for ZP-CI/OFDM so that frequency diversity gain can be further utilized and the power efficiency of the system is improved.
基金the National Natural Science Foundation of China(52303218 and 52303222)the China Postdoctoral Science Foundation(2022M720314)+1 种基金the Natural Science Foundation of Fujian Province(2023J01403)the Beijing Postdoctoral Science Foundation(2023-zz-101)for funding。
文摘With the continuous improvement of photovoltaic efficiency in the organic photovoltaic(OPV),interface engineering has emerged as a pivotal issue in their practical deployment.Currently,the robust crystallinity of small molecule electron transport layers(ETLs)and the poor film-forming abilities of conjugated polymer ETLs are a huge obstacle in this field.Herein,an innovative and efficient nonconjugated polymer ETL,namely PNDI-SO,which contains polar cationic segments for solubility and conjugated units for efficient charge transport in stable OPV cells,is reported.Endowed with suitable energy levels and excellent electron extraction capabilities,PNDI-SO-based OPV cells attain a power conversion efficiency(PCE)of 18.54%.Furthermore,compared with conventional OPV cells utilizing PFN-Br or PDINN,PNDI-SO substantially enhances long-term stability under continuous illumination,evidenced by a T80 lifetime(signifying retention of 80% of initial performance)exceeding 1250 h.Notably,through scanning electron microscope,we verified that PNDI-SO achieves a harmonious balance between film-forming ability and charge transport properties for ETL,enabling the blade-coating OPV based on PBDB-TF:BTP-eC9 to achieve a PCE of 17.47%.These results suggest the potential of PNDI-SO as a promising interface material for industrial printing applications in OPV fabrication.
基金supported by the 2022 Sanya Science and Technology Innovation Project,China(No.2022KJCX03)the Sanya Science and Education Innovation Park,Wuhan University of Technology,China(Grant No.2022KF0028)the Hainan Provincial Joint Project of Sanya Yazhou Bay Science and Technology City,China(Grant No.2021JJLH0036).
文摘This study investigates the Maximum Power Point Tracking(MPPT)control method of offshore windphotovoltaic hybrid power generation system with offshore crane-assisted.A new algorithm of Global Fast Integral Sliding Mode Control(GFISMC)is proposed based on the tip speed ratio method and sliding mode control.The algorithm uses fast integral sliding mode surface and fuzzy fast switching control items to ensure that the offshore wind power generation system can track the maximum power point quickly and with low jitter.An offshore wind power generation system model is presented to verify the algorithm effect.An offshore off-grid wind-solar hybrid power generation systemis built in MATLAB/Simulink.Compared with other MPPT algorithms,this study has specific quantitative improvements in terms of convergence speed,tracking accuracy or computational efficiency.Finally,the improved algorithm is further analyzed and carried out by using Yuankuan Energy’s ModelingTech semi-physical simulation platform.The results verify the feasibility and effectiveness of the improved algorithm in the offshore wind-solar hybrid power generation system.
基金supported by the National Natural Science Foundation of China (No. 60906012)the Analog Devices Inc. (ADI)
文摘A low power high performance Delta-Sigma modulator for portable measurement applications is presented. To reduce power consumption while maintaining high performance, a fully feedforward architecture with a comprehensive system-level design is implemented. As a key building block, a novel power efficient current mirror operational transconductance amplifier (OTA) with a fast-settling less-error switched-capacitor common-mode feedback (SC CMFB) circuit is introduced, and the effects of both gain nonlinearity and 1/f noise of OTA are discussed. A new method to determine the voltage gain of an OTA is also proposed. The bottom terminal parasitic effect of poly-insulator-poly (PIP) capacitors is considered. About an extra 20% of capacitance is added to the total capacitance load. A power and area efficient resonator is adopted to realize a coefficient of 1/90 for 50% power and 75% area reduction compared with conventional designs. The chip is implemented in a low cost 0.35 μm complementary metal oxide semiconductor (CMOS) process. The total power consumption is 20 μW with a 1.5 V supply, and the measured dynamic range (DR) is 95 dB over a 1 kHz bandwidth. Experimental results show that a high figure-of-merit (FOM) is achieved for the designed modulator in comparison with those from the literature.
基金Project supported by the Ministry of Science & Technology of China(No.2008BAI55B07)the State Key Laboratory of ASIC and System,Fudan University,China(No.09MS009).
文摘The analysis and design of a semi-passive radio frequency identification（RFID） tag is presented.By studying the power transmission link of the backscatter RFID system and exploiting a power conversion efficiency model for a multi-stage AC-DC charge pump,the calculation method for semi-passive tag＇s read range is proposed.According to different read range limitation factors,an intuitive way to define the specifications of tag＇s power budget and backscatter modulation index is given.A test chip is implemented in SMIC 0.18μm standard CMOS technology under the guidance of theoretical analysis.The main building blocks are the threshold compensated charge pump and low power wake-up circuit using the power triggering wake-up mode.The proposed semi-passive tag is fully compatible to EPC C1G2 standard.It has a compact chip size of 0.54 mm^2,and is adaptable to batteries with a 1.2 to 2.4 V output voltage.
基金Supported by the National Natural Science Foundation of China under Grant No 11335003
文摘A polymeric nanopore membrane with selective ionic transport has been proposed as a potential device to convert the chemical potential energy in salinity gradients to electrical power. However, its energy conversion efficiency and power density are often limited due to the challenge in reliably controlling the size of the nanopores with the conventional chemical etching method. Here we report that without chemical etching, polyimide （PI） membranes irradiated with GeV heavy ions have negatively charged nanopores, showing nearly perfect selectivity for cations over anions, and they can generate electrical power from salinity gradients. We further demonstrate that the power generation efficiency of the PI membrane approaches the theoretical limit, and the maximum power density reaches 130m W/m2 with a modified etching method, outperforming the previous energy conversion device that was made of polymeric nanopore membranes.
基金partially supported by the National Natural Science Foundation of China(61571225,61271255,61232016,U1405254)the Open Foundation of Jiangsu Engineering Center of Network Monitoring(Nanjing University of Information Science and Technology)(Grant No.KJR1509)+2 种基金the PAPD fundthe CICAEET fundShenzhen Strategic Emerging Industry Development Funds(JSGG20150331160845693)
文摘Considering that perfect channel state information(CSI) is difficult to obtain in practice,energy efficiency(EE) for distributed antenna systems(DAS) based on imperfect CSI and antennas selection is investigated in Rayleigh fading channel.A novel EE that is defined as the average transmission rate divided by the total consumed power is introduced.In accordance with this definition,an adaptive power allocation(PA) scheme for DAS is proposed to maximize the EE under the maximum transmit power constraint.The solution of PA in the constrained EE optimization does exist and is unique.A practical iterative algorithm with Newton method is presented to obtain the solution of PA.The proposed scheme includes the one under perfect CSI as a special case,and it only needs large scale and statistical information.As a result,the scheme has low overhead and good robustness.The theoretical EE is also derived for performance evaluation,and simulation result shows the validity of the theoretical analysis.Moreover,EE can be enhanced by decreasing the estimation error and/or path loss exponents.
基金supported by the Key Research and Development Program of Hubei Province(2023BAB116)the National Natural Science Foundation of China(52203238,52273196,52073221)the Fundamental Research Funds for the Central Universities of China(WUT:2021III016JC).
文摘All polymer solar cells(all-PSCs)promise mechanically-flexible and morphologically-stable organic photovoltaics and have aroused increased interests very recently.However,due to their disorderly conformation structures within the photoactive film,inefficient charge generation and carrier transport are observed which lead to inferior photovoltaic performance compared to smaller molecular acceptor-based photovoltaics.Here,by diluting PM6 with a cutting-edge polymeric acceptor PY-IT and diluting PY-IT with PM6 or D18,donor-dominating or acceptor-dominating heterojunctions were prepared.Synchrotron X-ray and multiple spectrometer techniques reveal that the diluted heterojunctions receive increased structural order,translating to enhanced carrier mobility,improved exciton diffusion length,and suppressed non-radiative recombination loss during the power conversion.As the results,the corresponding PM6+1%PY-IT/PY-IT+1%D18 and PM6+1%PY-IT/PY-IT+1%PM6 devices fabricated by layer-by-layer deposition received superior power conversion efficiency(PCE)of 19.4%and 18.8%respectively,along with enhanced operational lifetimes in air,outperforming the PCE of 17.5%in the PM6/PY-IT reference device.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12005031 and 12275041)the Natural Science Fund from the Interdisciplinary Project of Dalian University(Grant No.DLUXK-2023-QN-001)。
文摘Due to a series of challenges such as low-orbit maintenance of satellites, the air-breathing electric propulsion has got widespread attention. Commonly, the radio frequency ion thruster is favored by low-orbit missions due to its high specific impulse and efficiency. In this paper, the power transfer efficiency of the radio frequency ion thruster with different gas compositions is studied experimentally, which is obtained by measuring the radio frequency power and current of the antenna coil with and without discharge operation. The results show that increasing the turns of antenna coils can effectively improve the radio frequency power transfer efficiency, which is due to the improvement of Q factor. In pure N_2 discharge,with the increase of radio frequency power, the radio frequency power transfer efficiency first rises rapidly and then exhibits a less steep increasing trend. The radio frequency power transfer efficiency increases with the increase of gas pressure at relatively high power, while declines rapidly at relatively low power. In N_(2)/O_(2) discharge, increasing the N_(2) content at high power can improve the radio frequency power transfer efficiency, but the opposite was observed at low power. In order to give a better understanding of these trends, an analytic solution in limit cases is utilized, and a Langmuir probe was employed to measure the electron density. It is found that the evolution of radio frequency power transfer efficiency can be well explained by the variation of plasma resistance, which is related to the electron density and the effective electron collision frequency.
基金National Natural Science Foundation of China(Grant Nos.51925206,52302052)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0450301)+1 种基金Yunnan Provincial Science and Technology Project at Southwest United Graduate School(Grant No.202302AO370013)Huacai Solar Co.,Ltd.
文摘Self-assembled monolayers(SAMs)have recently emerged as excellent hole transport materials in inverted perovskite solar cells(PSCs)owing to their ability to minimize parasitic absorption,regulate energy level alignment,and passivate perovskite defects.Herein,we design and synthesize a novel dimethyl acridinebased SAM,[2-(9,10-dihydro-9,9-dimethylacridine-10-yl)ethyl]phosphonic acid(2PADmA),and employ it as a hole-transporting layer in inverted PSCs.Experimental results show that the 2PADmA SAM can modulate perovskite crystallization,facilitate carrier transport,passivate perovskite defects,and reduce nonradiative recombination.Consequently,the 2PADmA-based device achieves an enhanced power conversion efficiency(PCE)of 24.01%and an improved fill factor(FF)of 83.92%compared to the commonly reported[2-(9H-carbazol-9-yl)ethyl]phosphonic acid(2PACz)-based control device with a PCE of 22.32%and FF of 78.42%,while both devices exhibit comparable open-circuit voltage and short-circuit current density.In addition,2PADmA-based devices exhibit outstanding dark storage and thermal stabilities,retaining approximately~98%and 87%of their initial PCEs after 1080 h of dark storage and 400 h of heating at 85°C,respectively,both considerably superior to the control device.
基金supported in part by the National Research Foundation of Korea(NRF)(No.RS-2025-00554650)supported by the Chung-Ang University research grant in 2024。
文摘With the accelerated growth of the Internet of Things(IoT),real-time data processing on edge devices is increasingly important for reducing overhead and enhancing security by keeping sensitive data local.Since these devices often handle personal information under limited resources,cryptographic algorithms must be executed efficiently.Their computational characteristics strongly affect system performance,making it necessary to analyze resource impact and predict usage under diverse configurations.In this paper,we analyze the phase-level resource usage of AES variants,ChaCha20,ECC,and RSA on an edge device and develop a prediction model.We apply these algorithms under varying parallelism levels and execution strategies across key generation,encryption,and decryption phases.Based on the analysis,we train a unified Random Forest model using execution context and temporal features,achieving R2 values up to 0.994 for power and 0.988 for temperature.Furthermore,the model maintains practical predictive performance even for cryptographic algorithms not included during training,demonstrating its ability to generalize across distinct computational characteristics.Our proposed approach reveals how execution characteristics and resource usage interacts,supporting proactive resource planning and efficient deployment of cryptographic workloads on edge devices.As our approach is grounded in phase-level computational characteristics rather than in any single algorithm,it provides generalizable insights that can be extended to a broader range of cryptographic algorithms that exhibit comparable phase-level execution patterns and to heterogeneous edge architectures.
基金financially supported by the National Natural Science Foundation of China (52462032, 62274018, 52462031)Natural Science Foundation of Yunnan Province (202501AT070353, 202101BE070001-049)+2 种基金the Xinjiang Construction Corps Key Areas of Science and Technology Research Project (2023AB029)the Tianchi Talent Program of Xinjiang Uygur Autonomous Region (2024, Jiangzhao Chen)the Key Project of Chongqing Overseas Students Returning to China Entrepreneurship and Innovation Support Plan (cx2023006)。
文摘In recent years, the research advancements have high-lighted the critical role of the A-site cation in determining the optoelectronic and physicochemical properties of organicinorganic lead halide perovskites. Mixed-cation perovskites(MCPs) have been extensively used as absorber thin films in perovskite solar cells(PSCs), achieving high power conversion efficiencies(PCE) over 26%^([1, 2]).
基金support from the National Natural Science Foundation of China(62275057)the Guangxi Natural Science Foundation(2023GXNSFFA026004 and 2022GXNSFDA035066)+2 种基金the Innovation Project of Guangxi Graduate Education(YCBZ2024034)Natural Science Foundation of Ningbo under grant(2022J149)Natural Science Foundation of Ningbo under grant(2022A-230-G)
文摘Trap-assisted charge recombination is one of the primary limitationsof restricting the performance of organic solar cells. However, effectivelyreducing the presence of traps in the photoactive layer remains challenging.Herein, wide bandgap polymer donor PTzBI-dF is demonstrated as an effectivemodulator for enhancing the crystallinity of the bulk heterojunction active layerscomposed of D18 derivatives blended with Y6, leading to dense and orderedmolecular packings, and thus, improves photoluminescence quenching properties.As a result, the photovoltaic devices exhibit reduced trap-assisted charge recombinationlosses, achieving an optimized power conversion efficiency of over 19%.Besides the efficiency enhancement, the devices comprised of PTzBI-dF as athird component simultaneously attain decreased current leakage, improved chargecarrier mobilities, and suppressed bimolecular charge recombination, leading toreduced energy losses. The advanced crystalline structures induced by PTzBI-dFand its characteristics, such as well-aligned energy level, and complementaryabsorption spectra, are ascribed to the promising performance improvements.Our findings suggest that donor phase engineering is a feasible approach to tuning the molecular packings in the active layer, providingguidelines for designing effective morphology modulators for high-performance organic solar cells.
基金support from the National Natural Science Foundation of China(52303259,52373176)Open Cooperation Foundation of the Department of Chemical Science of Henan University.
文摘Strategic design of solid additives for regulating molecular aggregation and crystallinity in organic photovoltaic systems is crucial for enhancing device efficiency and stability.Herein,we introduce 3,5-dibromoanisole(DBA),a volatile solid additive synergistically integrating halogen and alkoxy functionalities,to optimize the PM6:Y6 active layer.DBA simultaneously interacts with both PM6 and Y6,promoting face-on molecular orientation and fibrillar network formation.Consequently,DBA-treated devices achieve a power conversion efficiency(PCE)of 18.34%,with a short-circuit current density(J_(SC))of 28.24 mA·cm^(–2) and a fill factor(FF)of 78.6%,surpassing the control device(PCE=17.13%).Notably,the DBA additive exhibits exceptional stability and demonstrates broad applicability across multiple material systems.This study establishes a universal framework for designing multifunctional solid additives,paving the way for scalable,high-efficiency organic solar cells(OSCs).
基金support from the National Natural Science Foundation of China(Grant Nos.52371197,51671139).
文摘The Shockley-Queisser(S-Q)model sets a theoretical limit on the power conversion efficiency(PCE)of single-junction solar cells at around 33%.Recently,a PCE of 50%-60%was achieved for the first time in n-type singlejunction Si solar cells by inhibiting light conversion to heat at low temperatures.Understanding these new observations opens tremendous opportunities for designing solar cells with even higher PCE to provide efficient and powerful energy sources for cryogenic devices and outer and deep space explorations.
基金supported by the Science,Technology,Innovation Commission of Shenzhen Municipality(GJHZ20220913143204008)Postdoctoral Research Project Funding in Shaanxi Province.
文摘The rapid advancement of metal halide perovskites can be attributed to their exceptional optoelectronic properties and facile solution processing technique.Noteworthy strides have been achieved in the realm of perovskite solar cells(PSCs),with a certified power conversion efficiency(PCE)escalating to 26.7%over the course of a decade,positioning them as promising contenders for next-generation photovoltaic technologies[1].However,the formation of crystal defects,including anion/cation vacancies,Pb–I antisite defects,and uncoordinated Pb^(2+),along the surface and grain boundaries(GBs)of perovskite layers during the solution processing stage poses a significant challenge,compromising the photoelectric performance and stability of PSCs.
基金the financial supports from the National Key R&D Program of China(2019YFB1503200)the GDUPS(2016)+4 种基金the NSF of Guangdong Province(2019B1515120050)the Fundamental Research Funds for the Central Universities(19lgjc07)the financial support from the Guangdong Basic and Applied Basic Research Foundation(2019A1515110770)National Key Research and Development Program of China(2017YFA0206600)National Natural Science Foundation of China(51773045,21772030,51922032,21961160720)for financial support
文摘In this research highlight,recent significant advances with hot-assisted blade-coating or air knife-assisted blade-coating of different perovskite compositions with bandgaps ranging from 1.3 eV to 1.9 eV(i.e.widebandgap or small-bandgap perovskites with mixed cations and anions,2D/3D perovskites,Pb/Sn binary perovskites,and all-inorganic perovskites)for single-junction or tandem PSCs are discussed,with an emphasis on elucidating the distinct ink formulation engineering strategies,crystal growth mechanisms,crystallization kinetics,and optoelectronic properties of the different perovskite compositions.
文摘Current high power load simulators are generally incapable of obtaining both high loading performance and high energy efficiency. Simulators with high energy efficiency are used to simulate static-state load, and those with high dynamic performance typically have low energy efficiency. In this paper, the variants of secondary control（VSC） with power recovery are developed to solve this problem for loading hydraulic driving devices that operate under variable pressure, unlike classical secondary control（CSC） that operates in constant pressure network. Hydrostatic secondary control units are used as the loading components, by which the absorbed mechanical power from the tested device is converted into hydraulic power and then fed back into the tested system through 4 types of feedback passages（FPs）. The loading subsystem can operate in constant pressure network, controlled variable pressure network, or the same variable pressure network as that of the tested device by using different FPs. The 4 types of systems are defined, and their key techniques are analyzed, including work principle, simulating the work state of original tested device, static operation points, loading performance, energy efficiency, and control strategy, etc. The important technical merits of the 4 schemes are compared, and 3 of the schemes are selected, designed, simulated using AMESim and evaluated. The researching results show that the investigated systems can simulate the given loads effectively, realize the work conditions of the tested device, and furthermore attain a high power recovery efficiency that ranges from 0.54 to 0.85, even though the 3 schemes have different loading performances and energy efficiencies. This paper proposes several loading schemes that can achieve both high dynamic performance and high power recovery efficiency.
基金Project(21875286)supported by the National Natural Science Foundation of China。
文摘The rational design of polymer acceptors with strong and broad absorption is critical to improve photovoltaic performance.In this work,a new polymer acceptor PY9-T based on heptacyclic benzotriazole(Y9-C16)as a building block and thiophene unit as the linking unit was synthesized,which exhibited a low bandgap(1.37 eV)and a high extinction coefficient of the neat film(1.44×10^(5) cm^(−1)).When PY9-T was blended with the wide bandgap polymer donor PBDB-T,the all-polymer solar cells(APSCs)showed a high power conversion efficiency(PCE)of 10.45%with both high open circuit voltage of 0.881 V and short-circuit current density of 19.82 mA/cm^(2).In addition,APSCs based on PY9-T show good thermal stability,as evidenced by slight changes morphologies when annealed at 100℃.These results suggest that Y9-C16 provides a new building block to develop efficient and stable polymer acceptors.
基金financially supported by the National Natural Science Foundation of China(No.52172205)。
文摘The self-assembly process for compatible functional layers of devices is a simple,feasible,and energy-saving strategy.In mesoporous perovskite solar cells(PSCs),compact and scaffold TiO_(2) films generally function as the hole-blocking and electron-transporting layers,respectively.However,both of these layers are usually generated through a high-temperature annealing process.Here,we deposited TiO_(2) compact films through a room-temperature self-assembly process as effective hole-blocking layers for PSCs.The thickness of TiO_(2) compact films can be easily controlled by the deposition time.Through the optimization of TiO_(2) compact films(80 nm),the power conversion efficiency(PCE)of mesoporous PSCs without and with hole conductor layers increases up to 10.66%and 17.95%,respectively.Notably,an all-low-temperature planar PSC with the self-assembled TiO_(2) layer exhibits a PCE of 16.41%.
