An automatic IQ phase calibration method implemented in a 2.4GHz direct conversion receiver is proposed. It uses a delay locked loop （DLL） with a proposed quadrature phase detector to greatly reduce the phase error....An automatic IQ phase calibration method implemented in a 2.4GHz direct conversion receiver is proposed. It uses a delay locked loop （DLL） with a proposed quadrature phase detector to greatly reduce the phase error. The receiver is fabricated in a 0.18μm CMOS process. Measurements show that the IQ phase error can be calibrated within 1°,which satisfies the system requirement.展开更多
LiDAR and camera are two of the most common sensors used in the fields of robot perception,autonomous driving,augmented reality,and virtual reality,where these sensors are widely used to perform various tasks such as ...LiDAR and camera are two of the most common sensors used in the fields of robot perception,autonomous driving,augmented reality,and virtual reality,where these sensors are widely used to perform various tasks such as odometry estimation and 3D reconstruction.Fusing the information from these two sensors can significantly increase the robustness and accuracy of these perception tasks.The extrinsic calibration between cameras and LiDAR is a fundamental prerequisite for multimodal systems.Recently,extensive studies have been conducted on the calibration of extrinsic parameters.Although several calibration methods facilitate sensor fusion,a comprehensive summary for researchers and,especially,non-expert users is lacking.Thus,we present an overview of extrinsic calibration and discuss diverse calibration methods from the perspective of calibration system design.Based on the calibration information sources,this study classifies these methods as target-based or targetless.For each type of calibration method,further classification was performed according to the diverse types of features or constraints used in the calibration process,and their detailed implementations and key characteristics were introduced.Thereafter,calibration-accuracy evaluation methods are presented.Finally,we comprehensively compare the advantages and disadvantages of each calibration method and suggest directions for practical applications and future research.展开更多
CO_(2)reduction technology can promote the resource utilization of carbon and help alleviate global warming and energy supply pressure.It is an effective way to achieve energy conversion and utilization.Covalent organ...CO_(2)reduction technology can promote the resource utilization of carbon and help alleviate global warming and energy supply pressure.It is an effective way to achieve energy conversion and utilization.Covalent organic frameworks(COFs)are porous crystalline materials formed by connecting organic monomers through covalent bonds.They have the characteristics of functional diversity and rich chemical properties.Their advantages,such as high porosity,a wide range of visible light absorption,and excellent charge separation efficiency,give them good potential in CO_(2)capture,separation,and conversion.Currently,Cu is a key metal in the catalytic CO_(2)reduction reaction(CO_(2)RR)for the preparation of high-value-added chemicals.The preparation of highly stable and large-pore Cu-based COFs using COFs as an ideal sacrificial template for loading Cu can be used to develop high-performance electrocatalysts and photocatalysts.In this review,we discuss the latest advancements in this field,including the development of various Cu-based COFs and their applications as catalysts for CO_(2)RR.Here,we mainly introduce the synthesis strategies,some important characterization information,and the applications of electrocatalytic and photocatalytic CO_(2)conversion using these previously reported Cu-based COFs.展开更多
Photocatalysis is an important technology for using solar energy to produce hydrogen,convert CO_(2) to synthetic fuels,and decrease persistent pollutant.However,conventional photocatalysts have limitations,including p...Photocatalysis is an important technology for using solar energy to produce hydrogen,convert CO_(2) to synthetic fuels,and decrease persistent pollutant.However,conventional photocatalysts have limitations,including poor spectral absorption,inefficient charge separation,and structural instability under operational stress,which demand innovative durable materials with tailored electronic properties.Nanodiamond(ND)has recently been recognized as a suitable material because of its exceptional chemical stability,superior charge carrier mobility,and possible surface functionalization.While its intrinsic wide bandgap limits its response to visible-light,different methods have been demonstrated to activate its catalytic potential.Here,several emerging strategies for improving the catalytic performance of ND-based photocatalytic systems are summarized,including surface functionalization,plasmonic hybridization,heteroatom doping,and heterostructure design.And the structure-activity relationship and design principle are proposed to improve the light harvesting,charge transport,and redox kinetics for constructing high efficiency ND-based photocatalysts used in the renewable energy and environmental industries.展开更多
In data communication,limited communication resources often lead to measurement bias,which adversely affects subsequent system estimation if not effectively handled.This paper proposes a novel bias calibration algorit...In data communication,limited communication resources often lead to measurement bias,which adversely affects subsequent system estimation if not effectively handled.This paper proposes a novel bias calibration algorithm under communication constraints to achieve accurate system states of the interested system.An output-based event-triggered scheme is first employed to alleviate transmission burden.Accounting for the limited-communication-induced measurement bias,a novel bias calibration algorithm following the Kalman filtering line is developed to restrain the effect of the measurement bias on system estimation,thereby achieving accurate system state estimates.Subsequently,the Field Programmable Gate Array(FPGA)implementation of the proposed algorithm is also realized with the hope of providing fast bias calibration in practical scenarios.A simulation about a numerical example and a practical example(for gyroscope’s angular velocity bias calibration)on MATLAB is provided to demonstrate the feasibility and effectiveness of the proposed algorithm.展开更多
To synergistically recover alumina and alkali from red mud(RM),the structural stability and conversion mechanism of hydroandradite(HA)from hydrogarnet(HG)were investigated via the First-principles,XRF,XRD,PSD and SEM ...To synergistically recover alumina and alkali from red mud(RM),the structural stability and conversion mechanism of hydroandradite(HA)from hydrogarnet(HG)were investigated via the First-principles,XRF,XRD,PSD and SEM methods,and a novel hydrothermal process based on the conversion principle was finally proposed.The crystal structure simulation shows that the HA with varied silicon saturation coefficients is more stable than HG,and the HA with a high iron substitution coefficient is more difficult to be converted from HG.The(110)plane of Fe_(2)O_(3) is easier to combine with HG to form HA,and the binding energy is 81.93 kJ/mol.The effects of raw material ratio,solution concentration and hydrothermal parameters on the conversion from HG to HA were revealed,and the optimal conditions for the alumina recovery were obtained.The recovery efficiencies of alumina and Na_(2)O from the RM are 63.06%and 97.34%,respectively,and the Na_(2)O content in the treated RM is only 0.13%.展开更多
We present the preparation and measurement of the radioactive isotope^(37)Ar,which was produced using thermal neutrons from a reactor,as a calibration source for liquid xenon time projection chambers.^(37)Ar is a low-...We present the preparation and measurement of the radioactive isotope^(37)Ar,which was produced using thermal neutrons from a reactor,as a calibration source for liquid xenon time projection chambers.^(37)Ar is a low-energy calibration source with a half-life of 35.01 days,making it suitable for calibration in the low-energy region of liquid xenon dark-matter experiments.Radioactive isotope^(37)Ar was produced by irradiating ^(36)Ar with thermal neutrons.It was subsequently measured in a gaseous xenon time projection chamber(GXe TPC)to validate its radioactivity.Our results demonstrate that^(37)Ar is an effective and viable calibration source that offers precise calibration capabilities in the low-energy domain of xenon-based detectors.展开更多
Laser-induced graphene(LIG)has emerged as a versatile,sustainable material for advanced energy technologies,offering a scalable,catalyst-free,and programmable method to directly convert carbon-rich substrates into por...Laser-induced graphene(LIG)has emerged as a versatile,sustainable material for advanced energy technologies,offering a scalable,catalyst-free,and programmable method to directly convert carbon-rich substrates into porous,conductive graphene.This single-step laser writing approach enables flexible,patternable electrodes without complex post-processing.With its high conductivity,large surface area,and tunable chemistry,LIG is well-suited for diverse applications including batteries,supercapacitors,dyesensitized solar cells(DSSCs),dual cells,water-splitting electrocatalysis,and triboelectric nanogenerators(TENGs).In energy storage,LIG improves charge transport,buffer volume changes,and provides a robust framework,enhancing capacitance,cycling stability,and rate capability.Its catalytic activity is further boosted through heteroatom doping or transition-metal incorporation,achieving HER/OER performance comparable to noble metals.In DSSCs,LIG functions as a flexible,low-cost alternative to platinum counter electrodes,while in TENGs,its strong triboelectric response and mechanical durability enable integration into self-powered,wearable systems.Despite the immense recent progress in this field,challenges remain regarding the scalability,long-term operational stability,and interfacial engineering of LIGbased composites.Further exploration into multi-laser systems,substrate diversity,and synergistic composite architectures will be crucial to optimizing device performance and reliability.Nevertheless,the green,cost-efficient,rapid,and programmable synthesis of LIG poses it as a cornerstone potential building block material in the development of future sustainable and multifunctional energy systems.Throughout the review we compare fabrication strategies,summarize performance metrics against relevant benchmarks,and identifying common mechanistic advantages conferred by the laser writing process.Remaining challenges-such as scale-up,precursor diversity,long-term environmental stability,and integration into complex device architectures-are outlined alongside prospective research directions.Collectively,this review article provides an in-depth perspective on the multifunctional nature of LIG,underscoring its promise in next-generation energy storage,conversion,harvesting applications,and laying the groundwork for future research directions.展开更多
Catalytic CO_(2)-to-methanol conversion presents a synergistic approach for concurrent greenhouse gas abatement and sustainable energy carrier synthesis.Single-atom catalysts(SACs)with maximized atomic utilization,tai...Catalytic CO_(2)-to-methanol conversion presents a synergistic approach for concurrent greenhouse gas abatement and sustainable energy carrier synthesis.Single-atom catalysts(SACs)with maximized atomic utilization,tailored electronic configurations and unique metal-support interactions,exhibit superior performance in CO_(2) activation and methanol synthesis.This review systematically compares reaction mechanisms and pathways across thermal,photocatalytic and electrocatalytic systems,emphasizing structure-activity relationships governed by active sites,coordination microenvironments and support functionalities.Through case studies of representative SACs,we elucidate how metal-support synergies dictate intermediate binding energetics and methanol selectivity.A critical analysis of reaction parameters(e.g.,temperature,pressure)reveals condition-dependent catalytic behaviors in thermal system,with fewer studies in photo/electrocatalytic systems identified as key knowledge gaps.While thermal catalysis achieves industrially viable methanol yields,the scalability is constrained by energy-intensive operation and catalyst sintering.Conversely,photo/electrocatalytic routes offer renewable energy integration but suffer from inefficient charge dynamics and mass transport limitations.To address the challenges,we propose strategic research priorities on precise design of active sites,synergy of multiple technological pathways,development of intelligent catalytic systems and diverse CO_(2) feedstock compatibility.These insights establish a framework for developing next-generation SACs,offering both theoretical foundations and technological blueprints for developing carbon-negative catalytic technologies.展开更多
Two-dimensional nanofluidic membranes have garnered considerable interest due to their potential for cost-effective osmotic energy harvesting.One promising approach to enhancing ion conductivity and selectivity is the...Two-dimensional nanofluidic membranes have garnered considerable interest due to their potential for cost-effective osmotic energy harvesting.One promising approach to enhancing ion conductivity and selectivity is the incorporation of vip additives.However,the traditional host-vip configuration can undermine the structural integrity of nanochannels owing to the inconsistent size and shape of these additives.Drawing inspiration from the intricate design of biological protein channels,which utilize small amino acid molecules as vips,we have addressed this issue by incorporating glycine,a common amino acid,into a vermiculite membrane using a simple vacuum-assisted infiltration method.The resulting vermiculite-glycine membrane demonstrates 1.8 times greater ionic conductivity and twice the power density compared to pure vermiculite membranes.Analysis based on glycine content,coupled with spectroscopic examination,reveals that ion conductivity is linked to the distribution of glycine molecules across three specific sites within the membrane.This suggests that glycine molecules—whether confined in voids,adsorbed onto nanochannel surfaces,or intercalated within multilayered vermiculite nanoparticles—enhance nanofluidic ion transport by modulating surface and space charge density,as well as strengthening hydrogen bonding,electrostatic interactions,and steric effects.This work reveals the specific interactions between amino acids and vermiculite,offering a novel path for advancing nanofluidic composite membranes and highlighting critical considerations for the proposed strategy.展开更多
Conventional locking/release mechanisms often face challenges in aircraft wing separation processes,such as excessive impact loads and insufficient synchronization.These may cause structural damage to the airframe or ...Conventional locking/release mechanisms often face challenges in aircraft wing separation processes,such as excessive impact loads and insufficient synchronization.These may cause structural damage to the airframe or attitude instability,seriously compromising mission reliability.To address this engineering challenge,this paper proposes a multi-point low-impact locking/release mechanism based on the mobility model and energy conversion strategy.Through establishing a DOF constraint framework system,this paper systematically analyzes the energy transfer and conversion characteristics during the wing separation process,reveals the generation mechanism of impact loads,and conducts research on low-impact design based on energy conversion strategy.Building on this foundation,a single-point locking/release mechanism employing parallel trapezoidal key shaft structure was designed,which increases frictional contact time and reduces the energy release rate,thereby achieving low-impact characteristics.The mechanism's performance was validated through physical prototype development and systematic functional testing(including unlocking force,synchronization,and impact tests).Experimental results demonstrate:(1)Under 14 kN preload condition,the maximum unlocking force was only 92.54 N,showing a linear relationship with preload that satisfies the"strong-connection/weak-unlock"design requirement;(2)Wing separation was completed within 46 ms,with synchronization time difference among three separation mechanisms stably controlled within 12-14 ms,proving rapid and reliable operation;(3)The unlocking impact acceleration ranged between 26 and 73 g,below the 100 g design limit,confirming the effectiveness of the energy conversion strategy.The proposed low-impact locking/release mechanism design method based on energy conversion strategy resolves the traditional challenges of high impact and synchronization deficiencies.The synergistic optimization mechanism of"structural load reduction and performance improvement"provides a highly reliable technical solution for wing separable mechanisms while offering novel design insights for wing connection/separation systems engineering.展开更多
As a controllable power generation method requiring no energy storage,Ocean Thermal Energy Conversion(OTEC)technology demonstrates characteristics of abundant reserves,low pollution,and round-the-clock stable operatio...As a controllable power generation method requiring no energy storage,Ocean Thermal Energy Conversion(OTEC)technology demonstrates characteristics of abundant reserves,low pollution,and round-the-clock stable operation.The free-standing cold-water pipe(CWP)in the system withstands various complex loads during operation,posing potential failure risks.To reveal the deformation and stress mechanisms of OTEC CWPs,this study first analyzes wave particle velocity and acceleration to determine wave loads at different water depths.Based on the Euler-Bernoulli beam model,a quasi-static load calculation model for OTEC CWPs was established.The governing equations were discretized using the finite difference method,and matrix equations were solved to analyze bending deformation,bending moments,and surface stresses at discrete points along the pipe.Results indicate that water depths within 50 m represent a critical zone where wave particle velocity,acceleration,and wave loads exhibit significant variations in harmonic patterns,while beyond 50 m depth wave loads decrease linearly.Ocean currents and surface wind-driven currents substantially influence the CWP’s lateral displacement.Considering the effect of clump weights,the maximum lateral displacement occurs at 600–800 m below sea level.Utilizing large-wall-thickness high-strength pipes at the top section significantly enhances the structural safety of the CWP system.展开更多
Large-volume presses(LVPs)are widely utilized in diverse research fields—including high-pressure physics,chemistry,materials science,and Earth and planetary sciences—to investigate the physical and chemical properti...Large-volume presses(LVPs)are widely utilized in diverse research fields—including high-pressure physics,chemistry,materials science,and Earth and planetary sciences—to investigate the physical and chemical properties of materials under extreme high-pressure and hightemperature conditions.A prerequisite for achieving reproducible property measurements is the determination and control of pressure within experimental setups.However,the lack of precise pressure calibration in LVPs hinders the broader application of such devices in ultrahigh-pressure studies.This study employs a suite of standard phase transition-based pressure markers—comprising metallic conductors,semiconductors,and minerals—through both in situ and ex situ identification approaches,to establish pressure calibration curves ranging from 0.4 to>30 GPa for various types of LVP installed at the Center for High Pressure Science and Technology Advanced Research(HPSTAR),Beijing,including piston–cylinder,cubic,and multi-anvil presses.The results provide a unified and traceable pressure reference for highpressure experiments conducted at HPSTAR,while also offering technical guidance and calibration standards for other researchers utilizing similar LVP systems,thereby enabling more consistent comparison between different laboratories.This work facilitates the advancement of LVP research toward broader applications in higher-pressure regimes.展开更多
Adult neurogenesis is generally considered to be very limited;however,there is increasing evidence that this phenomenon is conserved across species.Traditionally,research has focused on identifying precursor cells,tho...Adult neurogenesis is generally considered to be very limited;however,there is increasing evidence that this phenomenon is conserved across species.Traditionally,research has focused on identifying precursor cells,those that are actively dividing or have the potential to divide.Direct evidence of adult neurogenesis has been found in rats,mice,songbirds,and nonhuman primates.In humans,while the evidence is indirect,it strongly suggests that neurogenesis also occurs during adulthood.In mammals,this active neurogenesis is preserved by radial glial progenitors,which remain in specific niches in the subventricular zone of the lateral ventricles and in the subgranular zone of the hippocampal dentate gyrus(Kumar et al.,2019).展开更多
Cuprous oxide(Cu_(2)O) is one of the most promising catalysts for electrochemical conversion of CO_(2) into value-added C_(2) products.The efficiency of CO_(2)-to-C_(2) conversion is highly dependent on the Cu_(2)O cr...Cuprous oxide(Cu_(2)O) is one of the most promising catalysts for electrochemical conversion of CO_(2) into value-added C_(2) products.The efficiency of CO_(2)-to-C_(2) conversion is highly dependent on the Cu_(2)O crystal plane orientation and the corresponding adsorbed ^(*)CO species.Herein,we constructed high-index crystal planes(311) in Cu_(2)O(CO-Cu_(2)O) via a facile self-selective CO-induced strategy under a CO atmosphere,which was verified by high-resolution transmission electron microscopy(HR-TEM) and atomic force microscopy(AFM) results.By exploiting the high surface energy of the high index crystal planes,^(*)CO species are stabilized in CO-Cu_(2)O during CO_(2)RR,resulting in exceptional catalytic performance for CO_(2)-to-C_(2)products.In situ infrared spectroscopy revealed that both atop-type(^(*)CO_(atop)) and hollow-type(^(*)CO_(hollow)) adsorption of ^(*)CO species occurred on the CO-Cu_(2)O.The asymmetric C-C coupling energy barrier between ^(*)CO_(atop) and ^(*)CO_(hollow) in(311) crystal plane decreases by 47.8 % compared to the symmetric coupling of ^(*)CO_(atop) in conventional(100) crystal planes.Consequently,the Faradaic efficiency of C_(2) products generated with CO-Cu_(2)O was increased by as high as 100 % compared to that with pristine Cu_(2)O.展开更多
Methanol,a crucial C1 intermediate,bridges traditional fossil-based chemical processes with emerging sustainable catalytic technologies by serving as both a versatile hydrogenation product from CO/CO_(2)and an active ...Methanol,a crucial C1 intermediate,bridges traditional fossil-based chemical processes with emerging sustainable catalytic technologies by serving as both a versatile hydrogenation product from CO/CO_(2)and an active intermediate for hydrocarbon synthesis.Despite significant progress in methanol-to-hydrocarbon(MTH)conversion,a comprehensive understanding of reaction mechanisms remains essential to enhance catalyst design and industrial applicability.This review critically synthesizes recent advances in mechanistic insights related to methanol conversion and methanol-mediated catalytic processes.Firstly,we systematically outline key reaction pathways involved in initial carbon–carbon(C–C)bond formation through direct and indirect mechanisms,emphasizing significant breakthroughs from spectroscopic analyses and theoretical calculations.Subsequently,we highlight the autocatalytic characteristics and dual-cycle mechanisms underlying MTH processes,critically evaluating the roles of zeolite structures,pore sizes,topology,and acidity in governing product selectivity and catalyst stability.Additionally,we discuss cutting-edge developments in tandem catalytic systems employing methanol as a pivotal intermediate for CO_(x)hydrogenation,emphasizing the transferable mechanistic principles and catalytic insights.Finally,we identify future research directions,including elucidating precise hydrocarbon pool(HCP)intermediates,optimizing zeolite structures through computational-guided design,and developing robust catalytic systems leveraging advanced characterization methods and artificial intelligence.By integrating multidisciplinary approaches from catalytic science,materials engineering,and reaction engineering,this review provides actionable guidance towards rational design and optimization of advanced catalytic systems for efficient methanol conversion processes.展开更多
Accurate calibration of surgical instruments and ultrasound probes is essential for achieving high precision in image guided minimally invasive procedures.However,existing methods typically treat the calibration of th...Accurate calibration of surgical instruments and ultrasound probes is essential for achieving high precision in image guided minimally invasive procedures.However,existing methods typically treat the calibration of the needle tip and the ultrasound probe as two independent processes,lacking an integrated calibration mechanism,which often leads to cumulative errors and reduced spatial consistency.To address this challenge,we propose a joint calibration model that unifies the calibration of the surgical needle tip and the ultrasound probe within a single coordinate system.The method formulates the calibration process through a series of mathematical models and coordinate transformation models and employs a gradient descent based optimization to refine the parameters of these models.By establishing and iteratively optimizing a template coordinate system through modeling of constrained spherical motion,the proposed joint calibration model achieves submillimeter accuracy in needle tip localization.Building upon this,an N line based calibration model is developed to determine the spatial relationship between the probe and the ultrasound image plane,resulting in an average pixel deviation of only 1.2373 mm.Experimental results confirm that this unified modeling approach effectively overcomes the limitations of separate calibration schemes,significantly enhancing both precision and robustness,and providing a reliable computational model for surgical navigation systems that require high spatial accuracy without relying on ionizing radiation.展开更多
The quest for sustainable energy solutions has intensified the search for alternative feedstocks that can supplement or replace fossil fuels. Obtaining fuels or chemicals through the conversion of renewable biomass is...The quest for sustainable energy solutions has intensified the search for alternative feedstocks that can supplement or replace fossil fuels. Obtaining fuels or chemicals through the conversion of renewable biomass is a promising candidate [1,2]. Some noblemetal-based (e.g., Pt, Pd and Rh) catalysts exhibit significant catalytic activity to the conversion reaction of these biomass.展开更多
Quantum dots(QDs)can modulate the solar spectrum through the down-conversion mechanism to better match the spectral response of solar cells.Following previous work,this paper first tested the response of QD solar cell...Quantum dots(QDs)can modulate the solar spectrum through the down-conversion mechanism to better match the spectral response of solar cells.Following previous work,this paper first tested the response of QD solar cells to specific monochromatic light,and found that QDs can effectively improve the photoelectric conversion efficiency(PCE)in the ultraviolet(UV)band by comparison.Then the photoelectric properties of the QD solar cells are tested under the air-mass 1.5(AM1.5)and air-mass 0(AM0)spectra.The experimental results show that because the absorption band of QDs is in the UV region,the space solar cells in the AM0 spectrum can obtain better PCE after coating QDs.The research results show the technical route of space solar cells with down-conversion mechanism,and put forward an important direction for the application of space solar photovoltaic(PV)technology,and have a good application prospect.展开更多
Diamond combines many unique properties,including high stability,strong optical dispersion,excellent mechanical strength,and outstanding thermal conductivity.Its structure,surface groups,and electrical conductivity ar...Diamond combines many unique properties,including high stability,strong optical dispersion,excellent mechanical strength,and outstanding thermal conductivity.Its structure,surface groups,and electrical conductivity are also tunable,increasing its functional versatility.These make diamond and its related materials,such as its composites,highly promising for various applications in energy fields.This review summarizes recent advances and key achievements in energy storage and conversion,covering electrochemical energy storage(e.g.,batteries and supercapacitors),electrocatalytic energy conversion(e.g.,CO_(2)and nitrogen reduction reactions),and solar energy conversion(e.g.,photo-(electro)chemical CO_(2)and nitrogen reduction reactions,and solar cells).Current challenges and prospects related to the synthesis of diamond materials and the technologies for their energy applications are outlined and discussed.展开更多
文摘An automatic IQ phase calibration method implemented in a 2.4GHz direct conversion receiver is proposed. It uses a delay locked loop （DLL） with a proposed quadrature phase detector to greatly reduce the phase error. The receiver is fabricated in a 0.18μm CMOS process. Measurements show that the IQ phase error can be calibrated within 1°,which satisfies the system requirement.
基金Supported by Beijing Natural Science Foundation(Grant No.L241012)the National Natural Science Foundation of China(Grant No.62572468).
文摘LiDAR and camera are two of the most common sensors used in the fields of robot perception,autonomous driving,augmented reality,and virtual reality,where these sensors are widely used to perform various tasks such as odometry estimation and 3D reconstruction.Fusing the information from these two sensors can significantly increase the robustness and accuracy of these perception tasks.The extrinsic calibration between cameras and LiDAR is a fundamental prerequisite for multimodal systems.Recently,extensive studies have been conducted on the calibration of extrinsic parameters.Although several calibration methods facilitate sensor fusion,a comprehensive summary for researchers and,especially,non-expert users is lacking.Thus,we present an overview of extrinsic calibration and discuss diverse calibration methods from the perspective of calibration system design.Based on the calibration information sources,this study classifies these methods as target-based or targetless.For each type of calibration method,further classification was performed according to the diverse types of features or constraints used in the calibration process,and their detailed implementations and key characteristics were introduced.Thereafter,calibration-accuracy evaluation methods are presented.Finally,we comprehensively compare the advantages and disadvantages of each calibration method and suggest directions for practical applications and future research.
文摘CO_(2)reduction technology can promote the resource utilization of carbon and help alleviate global warming and energy supply pressure.It is an effective way to achieve energy conversion and utilization.Covalent organic frameworks(COFs)are porous crystalline materials formed by connecting organic monomers through covalent bonds.They have the characteristics of functional diversity and rich chemical properties.Their advantages,such as high porosity,a wide range of visible light absorption,and excellent charge separation efficiency,give them good potential in CO_(2)capture,separation,and conversion.Currently,Cu is a key metal in the catalytic CO_(2)reduction reaction(CO_(2)RR)for the preparation of high-value-added chemicals.The preparation of highly stable and large-pore Cu-based COFs using COFs as an ideal sacrificial template for loading Cu can be used to develop high-performance electrocatalysts and photocatalysts.In this review,we discuss the latest advancements in this field,including the development of various Cu-based COFs and their applications as catalysts for CO_(2)RR.Here,we mainly introduce the synthesis strategies,some important characterization information,and the applications of electrocatalytic and photocatalytic CO_(2)conversion using these previously reported Cu-based COFs.
文摘Photocatalysis is an important technology for using solar energy to produce hydrogen,convert CO_(2) to synthetic fuels,and decrease persistent pollutant.However,conventional photocatalysts have limitations,including poor spectral absorption,inefficient charge separation,and structural instability under operational stress,which demand innovative durable materials with tailored electronic properties.Nanodiamond(ND)has recently been recognized as a suitable material because of its exceptional chemical stability,superior charge carrier mobility,and possible surface functionalization.While its intrinsic wide bandgap limits its response to visible-light,different methods have been demonstrated to activate its catalytic potential.Here,several emerging strategies for improving the catalytic performance of ND-based photocatalytic systems are summarized,including surface functionalization,plasmonic hybridization,heteroatom doping,and heterostructure design.And the structure-activity relationship and design principle are proposed to improve the light harvesting,charge transport,and redox kinetics for constructing high efficiency ND-based photocatalysts used in the renewable energy and environmental industries.
基金support from the National Natural Science Foundation of China(Grant Nos.U2330206,U2230206,62173068)Sichuan Science and Technology Program(Grants Nos.2024NSFSC1483,2024ZYD0156,2023NSFC1962,DQ202412).
文摘In data communication,limited communication resources often lead to measurement bias,which adversely affects subsequent system estimation if not effectively handled.This paper proposes a novel bias calibration algorithm under communication constraints to achieve accurate system states of the interested system.An output-based event-triggered scheme is first employed to alleviate transmission burden.Accounting for the limited-communication-induced measurement bias,a novel bias calibration algorithm following the Kalman filtering line is developed to restrain the effect of the measurement bias on system estimation,thereby achieving accurate system state estimates.Subsequently,the Field Programmable Gate Array(FPGA)implementation of the proposed algorithm is also realized with the hope of providing fast bias calibration in practical scenarios.A simulation about a numerical example and a practical example(for gyroscope’s angular velocity bias calibration)on MATLAB is provided to demonstrate the feasibility and effectiveness of the proposed algorithm.
基金the financial support from the National Key R&D Program of China(No.2022YFC2904405)the National Natural Science Foundation of China(Nos.22078055,51774079)。
文摘To synergistically recover alumina and alkali from red mud(RM),the structural stability and conversion mechanism of hydroandradite(HA)from hydrogarnet(HG)were investigated via the First-principles,XRF,XRD,PSD and SEM methods,and a novel hydrothermal process based on the conversion principle was finally proposed.The crystal structure simulation shows that the HA with varied silicon saturation coefficients is more stable than HG,and the HA with a high iron substitution coefficient is more difficult to be converted from HG.The(110)plane of Fe_(2)O_(3) is easier to combine with HG to form HA,and the binding energy is 81.93 kJ/mol.The effects of raw material ratio,solution concentration and hydrothermal parameters on the conversion from HG to HA were revealed,and the optimal conditions for the alumina recovery were obtained.The recovery efficiencies of alumina and Na_(2)O from the RM are 63.06%and 97.34%,respectively,and the Na_(2)O content in the treated RM is only 0.13%.
基金supported by National Key R&D grant from the Ministry of Science and Technology of China(Nos.2021YFA1601600,2023YFA1606200)National Science Foundation of China(Nos.12090062,12105008)the Major State Basic Research Development Program of China.
文摘We present the preparation and measurement of the radioactive isotope^(37)Ar,which was produced using thermal neutrons from a reactor,as a calibration source for liquid xenon time projection chambers.^(37)Ar is a low-energy calibration source with a half-life of 35.01 days,making it suitable for calibration in the low-energy region of liquid xenon dark-matter experiments.Radioactive isotope^(37)Ar was produced by irradiating ^(36)Ar with thermal neutrons.It was subsequently measured in a gaseous xenon time projection chamber(GXe TPC)to validate its radioactivity.Our results demonstrate that^(37)Ar is an effective and viable calibration source that offers precise calibration capabilities in the low-energy domain of xenon-based detectors.
文摘Laser-induced graphene(LIG)has emerged as a versatile,sustainable material for advanced energy technologies,offering a scalable,catalyst-free,and programmable method to directly convert carbon-rich substrates into porous,conductive graphene.This single-step laser writing approach enables flexible,patternable electrodes without complex post-processing.With its high conductivity,large surface area,and tunable chemistry,LIG is well-suited for diverse applications including batteries,supercapacitors,dyesensitized solar cells(DSSCs),dual cells,water-splitting electrocatalysis,and triboelectric nanogenerators(TENGs).In energy storage,LIG improves charge transport,buffer volume changes,and provides a robust framework,enhancing capacitance,cycling stability,and rate capability.Its catalytic activity is further boosted through heteroatom doping or transition-metal incorporation,achieving HER/OER performance comparable to noble metals.In DSSCs,LIG functions as a flexible,low-cost alternative to platinum counter electrodes,while in TENGs,its strong triboelectric response and mechanical durability enable integration into self-powered,wearable systems.Despite the immense recent progress in this field,challenges remain regarding the scalability,long-term operational stability,and interfacial engineering of LIGbased composites.Further exploration into multi-laser systems,substrate diversity,and synergistic composite architectures will be crucial to optimizing device performance and reliability.Nevertheless,the green,cost-efficient,rapid,and programmable synthesis of LIG poses it as a cornerstone potential building block material in the development of future sustainable and multifunctional energy systems.Throughout the review we compare fabrication strategies,summarize performance metrics against relevant benchmarks,and identifying common mechanistic advantages conferred by the laser writing process.Remaining challenges-such as scale-up,precursor diversity,long-term environmental stability,and integration into complex device architectures-are outlined alongside prospective research directions.Collectively,this review article provides an in-depth perspective on the multifunctional nature of LIG,underscoring its promise in next-generation energy storage,conversion,harvesting applications,and laying the groundwork for future research directions.
基金supported by the National Natural Science Foundation of China(No.52300170).
文摘Catalytic CO_(2)-to-methanol conversion presents a synergistic approach for concurrent greenhouse gas abatement and sustainable energy carrier synthesis.Single-atom catalysts(SACs)with maximized atomic utilization,tailored electronic configurations and unique metal-support interactions,exhibit superior performance in CO_(2) activation and methanol synthesis.This review systematically compares reaction mechanisms and pathways across thermal,photocatalytic and electrocatalytic systems,emphasizing structure-activity relationships governed by active sites,coordination microenvironments and support functionalities.Through case studies of representative SACs,we elucidate how metal-support synergies dictate intermediate binding energetics and methanol selectivity.A critical analysis of reaction parameters(e.g.,temperature,pressure)reveals condition-dependent catalytic behaviors in thermal system,with fewer studies in photo/electrocatalytic systems identified as key knowledge gaps.While thermal catalysis achieves industrially viable methanol yields,the scalability is constrained by energy-intensive operation and catalyst sintering.Conversely,photo/electrocatalytic routes offer renewable energy integration but suffer from inefficient charge dynamics and mass transport limitations.To address the challenges,we propose strategic research priorities on precise design of active sites,synergy of multiple technological pathways,development of intelligent catalytic systems and diverse CO_(2) feedstock compatibility.These insights establish a framework for developing next-generation SACs,offering both theoretical foundations and technological blueprints for developing carbon-negative catalytic technologies.
基金supported by the National Natural Science Foundation of China(Grant No.22479097)the Shanghai Science and Technology Committee(Grant Nos.23ZR1433000)the National High-Level Talent Program for Young Scholars,the Start-up Fund(F.S.)from Shanghai Jiao Tong University,China.We also acknowledge the SJTU Instrument Analysis Centre for the measurements.
文摘Two-dimensional nanofluidic membranes have garnered considerable interest due to their potential for cost-effective osmotic energy harvesting.One promising approach to enhancing ion conductivity and selectivity is the incorporation of vip additives.However,the traditional host-vip configuration can undermine the structural integrity of nanochannels owing to the inconsistent size and shape of these additives.Drawing inspiration from the intricate design of biological protein channels,which utilize small amino acid molecules as vips,we have addressed this issue by incorporating glycine,a common amino acid,into a vermiculite membrane using a simple vacuum-assisted infiltration method.The resulting vermiculite-glycine membrane demonstrates 1.8 times greater ionic conductivity and twice the power density compared to pure vermiculite membranes.Analysis based on glycine content,coupled with spectroscopic examination,reveals that ion conductivity is linked to the distribution of glycine molecules across three specific sites within the membrane.This suggests that glycine molecules—whether confined in voids,adsorbed onto nanochannel surfaces,or intercalated within multilayered vermiculite nanoparticles—enhance nanofluidic ion transport by modulating surface and space charge density,as well as strengthening hydrogen bonding,electrostatic interactions,and steric effects.This work reveals the specific interactions between amino acids and vermiculite,offering a novel path for advancing nanofluidic composite membranes and highlighting critical considerations for the proposed strategy.
文摘Conventional locking/release mechanisms often face challenges in aircraft wing separation processes,such as excessive impact loads and insufficient synchronization.These may cause structural damage to the airframe or attitude instability,seriously compromising mission reliability.To address this engineering challenge,this paper proposes a multi-point low-impact locking/release mechanism based on the mobility model and energy conversion strategy.Through establishing a DOF constraint framework system,this paper systematically analyzes the energy transfer and conversion characteristics during the wing separation process,reveals the generation mechanism of impact loads,and conducts research on low-impact design based on energy conversion strategy.Building on this foundation,a single-point locking/release mechanism employing parallel trapezoidal key shaft structure was designed,which increases frictional contact time and reduces the energy release rate,thereby achieving low-impact characteristics.The mechanism's performance was validated through physical prototype development and systematic functional testing(including unlocking force,synchronization,and impact tests).Experimental results demonstrate:(1)Under 14 kN preload condition,the maximum unlocking force was only 92.54 N,showing a linear relationship with preload that satisfies the"strong-connection/weak-unlock"design requirement;(2)Wing separation was completed within 46 ms,with synchronization time difference among three separation mechanisms stably controlled within 12-14 ms,proving rapid and reliable operation;(3)The unlocking impact acceleration ranged between 26 and 73 g,below the 100 g design limit,confirming the effectiveness of the energy conversion strategy.The proposed low-impact locking/release mechanism design method based on energy conversion strategy resolves the traditional challenges of high impact and synchronization deficiencies.The synergistic optimization mechanism of"structural load reduction and performance improvement"provides a highly reliable technical solution for wing separable mechanisms while offering novel design insights for wing connection/separation systems engineering.
基金funded by Nansha District Science and Technology Project(Grant Number.2024ZD008)funded by China Geological Survey(Grant number:No.DD20230066,DD20242659).
文摘As a controllable power generation method requiring no energy storage,Ocean Thermal Energy Conversion(OTEC)technology demonstrates characteristics of abundant reserves,low pollution,and round-the-clock stable operation.The free-standing cold-water pipe(CWP)in the system withstands various complex loads during operation,posing potential failure risks.To reveal the deformation and stress mechanisms of OTEC CWPs,this study first analyzes wave particle velocity and acceleration to determine wave loads at different water depths.Based on the Euler-Bernoulli beam model,a quasi-static load calculation model for OTEC CWPs was established.The governing equations were discretized using the finite difference method,and matrix equations were solved to analyze bending deformation,bending moments,and surface stresses at discrete points along the pipe.Results indicate that water depths within 50 m represent a critical zone where wave particle velocity,acceleration,and wave loads exhibit significant variations in harmonic patterns,while beyond 50 m depth wave loads decrease linearly.Ocean currents and surface wind-driven currents substantially influence the CWP’s lateral displacement.Considering the effect of clump weights,the maximum lateral displacement occurs at 600–800 m below sea level.Utilizing large-wall-thickness high-strength pipes at the top section significantly enhances the structural safety of the CWP system.
基金supported by the National Science Foundation of China(Grant Nos.U1530402 and U1930401).
文摘Large-volume presses(LVPs)are widely utilized in diverse research fields—including high-pressure physics,chemistry,materials science,and Earth and planetary sciences—to investigate the physical and chemical properties of materials under extreme high-pressure and hightemperature conditions.A prerequisite for achieving reproducible property measurements is the determination and control of pressure within experimental setups.However,the lack of precise pressure calibration in LVPs hinders the broader application of such devices in ultrahigh-pressure studies.This study employs a suite of standard phase transition-based pressure markers—comprising metallic conductors,semiconductors,and minerals—through both in situ and ex situ identification approaches,to establish pressure calibration curves ranging from 0.4 to>30 GPa for various types of LVP installed at the Center for High Pressure Science and Technology Advanced Research(HPSTAR),Beijing,including piston–cylinder,cubic,and multi-anvil presses.The results provide a unified and traceable pressure reference for highpressure experiments conducted at HPSTAR,while also offering technical guidance and calibration standards for other researchers utilizing similar LVP systems,thereby enabling more consistent comparison between different laboratories.This work facilitates the advancement of LVP research toward broader applications in higher-pressure regimes.
文摘Adult neurogenesis is generally considered to be very limited;however,there is increasing evidence that this phenomenon is conserved across species.Traditionally,research has focused on identifying precursor cells,those that are actively dividing or have the potential to divide.Direct evidence of adult neurogenesis has been found in rats,mice,songbirds,and nonhuman primates.In humans,while the evidence is indirect,it strongly suggests that neurogenesis also occurs during adulthood.In mammals,this active neurogenesis is preserved by radial glial progenitors,which remain in specific niches in the subventricular zone of the lateral ventricles and in the subgranular zone of the hippocampal dentate gyrus(Kumar et al.,2019).
基金the financial support from the National Natural Science Foundation of China (Nos.U23A20677,22022610 and 52400137)"Pioneer" and "Leading Goose" R&D Program of Zhejiang (Nos.2022C03146 and 2023C03017)+2 种基金China Postdoctoral Science Foundation (No.2024T170805)Zhejiang Provincial Natural Science Foundation of China (No.LDT23E06015B06)the support of the Research Computing Center in College of Chemical and Biological Engineering at Zhejiang University for assistance with the calculations。
文摘Cuprous oxide(Cu_(2)O) is one of the most promising catalysts for electrochemical conversion of CO_(2) into value-added C_(2) products.The efficiency of CO_(2)-to-C_(2) conversion is highly dependent on the Cu_(2)O crystal plane orientation and the corresponding adsorbed ^(*)CO species.Herein,we constructed high-index crystal planes(311) in Cu_(2)O(CO-Cu_(2)O) via a facile self-selective CO-induced strategy under a CO atmosphere,which was verified by high-resolution transmission electron microscopy(HR-TEM) and atomic force microscopy(AFM) results.By exploiting the high surface energy of the high index crystal planes,^(*)CO species are stabilized in CO-Cu_(2)O during CO_(2)RR,resulting in exceptional catalytic performance for CO_(2)-to-C_(2)products.In situ infrared spectroscopy revealed that both atop-type(^(*)CO_(atop)) and hollow-type(^(*)CO_(hollow)) adsorption of ^(*)CO species occurred on the CO-Cu_(2)O.The asymmetric C-C coupling energy barrier between ^(*)CO_(atop) and ^(*)CO_(hollow) in(311) crystal plane decreases by 47.8 % compared to the symmetric coupling of ^(*)CO_(atop) in conventional(100) crystal planes.Consequently,the Faradaic efficiency of C_(2) products generated with CO-Cu_(2)O was increased by as high as 100 % compared to that with pristine Cu_(2)O.
基金the Inner Mongolia Natural Science Foundation(2023ZD05,2025JQ028,2025MS02001)the National Natural Science Foundation of China(22278238,22238004)+3 种基金the National Key Research and Development Program of China(2024YFE0211400)the Major Science and Technology Program of Inner Mongolia Autonomous Region(20212120326)the“Elite Talents Revitalize Inner Mongolia”Initiative–Tier-1 Talent Team(202410)the Ordos Science and Technology Breakthrough(JBGS2024003),and Ordos Laboratory for their financial support.
文摘Methanol,a crucial C1 intermediate,bridges traditional fossil-based chemical processes with emerging sustainable catalytic technologies by serving as both a versatile hydrogenation product from CO/CO_(2)and an active intermediate for hydrocarbon synthesis.Despite significant progress in methanol-to-hydrocarbon(MTH)conversion,a comprehensive understanding of reaction mechanisms remains essential to enhance catalyst design and industrial applicability.This review critically synthesizes recent advances in mechanistic insights related to methanol conversion and methanol-mediated catalytic processes.Firstly,we systematically outline key reaction pathways involved in initial carbon–carbon(C–C)bond formation through direct and indirect mechanisms,emphasizing significant breakthroughs from spectroscopic analyses and theoretical calculations.Subsequently,we highlight the autocatalytic characteristics and dual-cycle mechanisms underlying MTH processes,critically evaluating the roles of zeolite structures,pore sizes,topology,and acidity in governing product selectivity and catalyst stability.Additionally,we discuss cutting-edge developments in tandem catalytic systems employing methanol as a pivotal intermediate for CO_(x)hydrogenation,emphasizing the transferable mechanistic principles and catalytic insights.Finally,we identify future research directions,including elucidating precise hydrocarbon pool(HCP)intermediates,optimizing zeolite structures through computational-guided design,and developing robust catalytic systems leveraging advanced characterization methods and artificial intelligence.By integrating multidisciplinary approaches from catalytic science,materials engineering,and reaction engineering,this review provides actionable guidance towards rational design and optimization of advanced catalytic systems for efficient methanol conversion processes.
基金Support by Sichuan Science and Technology Program[2023YFSY0026,2023YFH0004].
文摘Accurate calibration of surgical instruments and ultrasound probes is essential for achieving high precision in image guided minimally invasive procedures.However,existing methods typically treat the calibration of the needle tip and the ultrasound probe as two independent processes,lacking an integrated calibration mechanism,which often leads to cumulative errors and reduced spatial consistency.To address this challenge,we propose a joint calibration model that unifies the calibration of the surgical needle tip and the ultrasound probe within a single coordinate system.The method formulates the calibration process through a series of mathematical models and coordinate transformation models and employs a gradient descent based optimization to refine the parameters of these models.By establishing and iteratively optimizing a template coordinate system through modeling of constrained spherical motion,the proposed joint calibration model achieves submillimeter accuracy in needle tip localization.Building upon this,an N line based calibration model is developed to determine the spatial relationship between the probe and the ultrasound image plane,resulting in an average pixel deviation of only 1.2373 mm.Experimental results confirm that this unified modeling approach effectively overcomes the limitations of separate calibration schemes,significantly enhancing both precision and robustness,and providing a reliable computational model for surgical navigation systems that require high spatial accuracy without relying on ionizing radiation.
文摘The quest for sustainable energy solutions has intensified the search for alternative feedstocks that can supplement or replace fossil fuels. Obtaining fuels or chemicals through the conversion of renewable biomass is a promising candidate [1,2]. Some noblemetal-based (e.g., Pt, Pd and Rh) catalysts exhibit significant catalytic activity to the conversion reaction of these biomass.
基金supported by the Science&Technology Development Fund of Tianjin Education Commission for Higher Education(No.2022KJ133).
文摘Quantum dots(QDs)can modulate the solar spectrum through the down-conversion mechanism to better match the spectral response of solar cells.Following previous work,this paper first tested the response of QD solar cells to specific monochromatic light,and found that QDs can effectively improve the photoelectric conversion efficiency(PCE)in the ultraviolet(UV)band by comparison.Then the photoelectric properties of the QD solar cells are tested under the air-mass 1.5(AM1.5)and air-mass 0(AM0)spectra.The experimental results show that because the absorption band of QDs is in the UV region,the space solar cells in the AM0 spectrum can obtain better PCE after coating QDs.The research results show the technical route of space solar cells with down-conversion mechanism,and put forward an important direction for the application of space solar photovoltaic(PV)technology,and have a good application prospect.
基金西南大学中央高校基本科研业务费项目(SWU-KT22030)重庆市教育委员会科学技术研究项目(KJQN202300205)Deutsche Forschungsgemeinschaft(DFG,German Research Foundation,457444676).
文摘Diamond combines many unique properties,including high stability,strong optical dispersion,excellent mechanical strength,and outstanding thermal conductivity.Its structure,surface groups,and electrical conductivity are also tunable,increasing its functional versatility.These make diamond and its related materials,such as its composites,highly promising for various applications in energy fields.This review summarizes recent advances and key achievements in energy storage and conversion,covering electrochemical energy storage(e.g.,batteries and supercapacitors),electrocatalytic energy conversion(e.g.,CO_(2)and nitrogen reduction reactions),and solar energy conversion(e.g.,photo-(electro)chemical CO_(2)and nitrogen reduction reactions,and solar cells).Current challenges and prospects related to the synthesis of diamond materials and the technologies for their energy applications are outlined and discussed.
