Land-use changes in coastal wetlands have led to a worldwide degradation of marine coastal ecosystems and a loss of the ecological services they provide. Ecological offsetting is a popular strategy and an effective mi...Land-use changes in coastal wetlands have led to a worldwide degradation of marine coastal ecosystems and a loss of the ecological services they provide. Ecological offsetting is a popular strategy and an effective mitigation measure for ecosystems that have been degraded, damaged, or destroyed and is critical for habitats where natural recovery is hindered. However, the current understanding of the theory and practice of ecological offsetting for coastal wetlands is extremely limited in many developing countries. We conducted a review of ecological offsetting for coastal wetlands projects and studies in China in 1979–2017 to explore the application and limitations of ecological offsetting theory. It was found that China's coastal ecological offsetting regime has recently entered a rapidly developing stage, with an increasing number of different types of offsetting projects conducted, but theoretical research lags behind practical applications. Considerable governmental, social, technological and ethical challenges remain to resolve. Coastal ecological offsetting schemes have been inconsistent in meeting conservation objectives or preventing net losses because of the challenges of ensuring they are fully consistent in practice(mainly in-kind offsets) and theory(mainly out-of-kind offsets). Ecological offsetting projects were primarily implemented by government, developers, and non-profit organizations. The available funding of coastal ecological offsetting projects is insufficient, which makes ecological offsetting a risky operation. Therefore, we propose strategies for improvement that integrate the consideration of theoretical and practical challenges in the offsetting process, while providing a scientific basis and directional guidance for the future practice of biodiversity conservation and environmental management.展开更多
Resale price maintenance(RPM) exerts both positive and negative influences on the market competition.Such duality and the consequent difficulties in presenting evidence have often become highly controversial issues in...Resale price maintenance(RPM) exerts both positive and negative influences on the market competition.Such duality and the consequent difficulties in presenting evidence have often become highly controversial issues in anti-monopoly law enforcement.We found that in reality,effects of jump-dealing and RPM can offset each other.This paper systematically proposed the offsetting theory of jump-dealing and RPM,and analyzed their policy implications for anti price monopoly,thus providing some simple principles and methods to the law enforcement against vertical price monopoly.This will not only reduce the possible "superfluous actions " in current law enforcement,but also help avoid compounded mistakes due to difficulties of enforcement.展开更多
Biodiversity offsetting plays a crucial role in managing the impacts of development on natural habitats. Developers, conservation groups, governments and financial institutions have used biodiversity offsetting to des...Biodiversity offsetting plays a crucial role in managing the impacts of development on natural habitats. Developers, conservation groups, governments and financial institutions have used biodiversity offsetting to design measurable conservation actions to compensate for significant residual adverse biodiversity impacts arising from development. However, the concepts and methodologies of biodiversity offsetting have rarely been systematically reviewed, and best practices are still lacking. This hinders the development and applications of this field, and makes it difficult for new researchers to learn, develop, and apply biodiversity offsetting. This paper aims to review research progress on biodiversity offsetting during the period of 1992 to 2019. We mainly used bibliometric analysis and social network analysis methods to expose the topic diversity, development and promotion of this research field, and assess collaboration among biodiversity offsetting scholars. Our research identified 1190 records, and revealed that the total number of publications increased rapidly since 2002. The most productive journal, country, and author were Biological Conservation, USA, and Dr. Maron M of University of Queensland, respectively. Co-author analysis identified that the 23 authors most relevant to biodiversity offsetting were involved in a collaboration network. And they were mainly from 30 countries in a collaboration network, and the authors from USA, Australia and the United Kingdom have the most cooperation, which mainly driven by policy related to biodiversity offsetting. Our review shows that biodiversity offsetting research is at an early stage of rapid development with topically diverse and collaborative science domains. The majority of studies focus on terrestrial environments, which makes the implementation of aquatic ecosystem is more difficult. Theoretical problems and the implications of research evolution and social network in biodiversity offsetting are discussed, and further development of the theory and methodologies of biodiversity offsetting and management was recommend.展开更多
Piecewise linear systems are prevalent in engineering practice,and can be categorized into symmetric and asymmetric piecewise linear systems.Considering that symmetry is a special case of asymmetry,it is essential to ...Piecewise linear systems are prevalent in engineering practice,and can be categorized into symmetric and asymmetric piecewise linear systems.Considering that symmetry is a special case of asymmetry,it is essential to investigate the broader model,namely the asymmetric piecewise linear system.The traditional averaging method is frequently used for studying nonlinear systems,particularly symmetric piecewise linear systems,with the harmonic response of the oscillator serving as a key prerequisite for calculating steady-state solutions.However,asymmetric systems inherently exhibit nonharmonic,asymmetric responses,rendering the traditional averaging method inapplicable.To overcome this limitation,this paper introduces an improved averaging method tailored for an oscillator characterized by asymmetric gaps and springs.Unlike the traditional method,which assumes a purely harmonic response,the improved averaging method redefines the system response as a superposition of a direct current(DC)term and a first harmonic component.Herein,the DC term can be regarded as the offset induced by model asymmetry.Furthermore,the DC term is treated as a slow variable function of time,with its time derivative assumed to be zero when calculating the steady-state solution,akin to the amplitude and phase in the traditional averaging method.Numerical validation demonstrates that the responses computed in both time and frequency domains with the improved averaging method exhibit greater accuracy compared with those derived from the traditional method.Leveraging these improved results,the study also examines the parameter effect,stability,and bifurcation phenomena within the amplitude-frequency responses.展开更多
The tiered geosynthetic-reinforced soil (GRS) walls have been increasingly applied in the high and steep retaining soil structures. However, very little is known about the design method for the tiered GRS wall in prac...The tiered geosynthetic-reinforced soil (GRS) walls have been increasingly applied in the high and steep retaining soil structures. However, very little is known about the design method for the tiered GRS wall in practice. This study is aimed at proposing an upper-bound stability analysis method of a tiered GRS wall. The proposed method was firstly validated by the existing results from the centrifuge test and the numerical method, and then a parametric study was performed to investigate the effects of the cohesionless backfill friction angle φ1 and the wall geometric parameters including the offset distance, the total wall height, the batter angle δ, the number of tiers n, and wall height ratio of adjacent tiers on the dimensionless equivalent earth pressure coefficient KT. The analysis results demonstrated that as the φ1 increases, the shear strength of backfill is enhanced and thus the KT or the total reinforcement tensile force decreases, and the KT decreases with the increase of the offset distance at the initial stage and then becomes stable when it reaches a certain critical value. For a fixed offset distance, the KT or the total reinforcement tensile force decreases with the increase of the δ. For the two-tiered GRS walls having the offset distance less than the critical value, the wall with the smaller wall height ratio has a larger KT. Further, the variation of the location of the critical failure surfaces of tiered GRS walls was presented in this study with the variation of the φ1 and the wall geometry.展开更多
Due to the neglect of the retrieval of communication parameters(including the symbol rate,the symbol timing offset,and the carrier frequency),the existing non-cooperative communication mode recognizers suffer from the...Due to the neglect of the retrieval of communication parameters(including the symbol rate,the symbol timing offset,and the carrier frequency),the existing non-cooperative communication mode recognizers suffer from the generality ability degradation and severe difficulty in distinguishing a large number of modulation modes,etc.To overcome these drawbacks,this paper proposes an efficient communication mode recognizer consisting of communication parameter estimation,the constellation diagram retrieval,and a classification network.In particular,we define a 2-D symbol synchronization metric to retrieve both the symbol rate and the symbol timing offset,whereas a constellation dispersity annealing procedure is devised to correct the carrier frequency accurately.Owing to the accurate estimation of these crucial parameters,high-regularity constellation maps can be retrieved and thus simplify the subsequent classification work.Numerical results show that the proposed communication mode recognizer acquires higher classification accuracy,stronger anti-noise robustness,and higher applicability of distinguishing multiple types,which presents the proposed scheme with vast applicable potentials in non-cooperative scenarios.展开更多
Artificial intelligence(AI)is transforming the tourism industry and affecting on natural ecology,making it more environmentally friendly,efficient and personalized.In 2025,AI technologies are being actively implemente...Artificial intelligence(AI)is transforming the tourism industry and affecting on natural ecology,making it more environmentally friendly,efficient and personalized.In 2025,AI technologies are being actively implemented to reduce the carbon footprint,optimize resources,and improve the travel experience.Here are the key applications of AI in environmentally sustainable smart tourism:AI in smart tourism is not just a technological trend,but a necessity for the sustainable development of the industry.Paper analyses personalized and green travel experience and smart tourism.AI-based applications(Google ARCore)allow tourists to get information about attractions without paper booklets.Virtual tours reduce the need for physical travel by reducing the carbon footprint.Platforms offer routes with minimal impact on nature(for example,hiking trails instead of car tours).Tourists can offset their carbon footprint through AI tools by financing tree planting.The introduction of AI solutions allows combining economic benefits with environmental responsibility,creating a future where travel becomes safer for the planet.Paper confirms idea about sustainable tourism development in developing countries and focus on premium ecotourism.Instead of mass tourism,AI helps promote unique destinations(safaris,diving,ethnographic tours),which increases income with less environmental damage.Smart cities with AI-driven transport and energy-saving solutions make tourism more sustainable.展开更多
This paper investigates the influence of the spanwise-distributed trailing-edge camber morphing on the dynamic stall characteristics of a finite-span wing at Re=2×10^(5).The mathematical model of the spanwise-dis...This paper investigates the influence of the spanwise-distributed trailing-edge camber morphing on the dynamic stall characteristics of a finite-span wing at Re=2×10^(5).The mathematical model of the spanwise-distributed trailing-edge camber morphing is established based on Chebyshev polynomials,and the deformed wing surface is modeled by a spline surface according to the rib's morphing in the chordwise direction.The Computational Fluid Dynamics(CFD)method is adopted to obtain flow-field results and aerodynamic forces.The SST-γmodel is introduced and the overset mesh technique is adopted.The numerical results show that the spanwisedistributed trailing-edge morphing obviously changes the aerodynamic and energy transfer characteristics of the dynamic stall.Especially when the phase difference between the trailing-edge motion and the wing pitch is-π/2,the interaction between the three-dimensional(3-D)Leading-Edge Vortex(LEV)and Trailing-Edge Vortex(TEV)is strengthened,and the work done by the aerodynamic force turns negative.This indicates that the trailing-edge deformation has the potential to suppress the oscillation amplitude of stall flutter.We also found that as the trailing-edge camber morphing varies more complexly along the spanwise direction,the suppression effect decreases accordingly.展开更多
Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)is considered to be the most potential light-absorbing material to replace CuInGaSe_(2)(CIGS),but the actual photoelectric conversion efficiency of such cells is much lower than that of CIG...Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)is considered to be the most potential light-absorbing material to replace CuInGaSe_(2)(CIGS),but the actual photoelectric conversion efficiency of such cells is much lower than that of CIGS.One of the reasons is the high recombination rate of carriers at the interface.In this paper,in order to reduce the carrier recombination,a new solar cell structure with double absorber layers of Al-doped ZnO(AZO)/intrinsic(i)-ZnO/CdS/CZTS_(x1)Se_(1−x1)(CZTSSe_(1))/CZTS_(x2)Se_(1−x2)(CZTSSe_(2))/Mo was proposed,and the optimal conduction band offsets(CBOs)of CdS/CZTSSe_(1) interface and CZTSSe_(1)/CZTSSe_(2) interface were determined by changing the S ratio in CZTSSe_(1) and CZTSSe_(2),and the effect of thickness of CZTSSe_(1) on the performance of the cell was studied.The efficiencies of the optimized single and double absorber layers reached 17.97%and 23.4%,respectively.Compared with the single absorber layer structure,the proposed structure with double absorber layers has better cell performance.展开更多
In-loop filters have been comprehensively explored during the development of video coding standards due to their remarkable noise-reduction capabilities.In the early stage of video coding,in-loop filters,such as the d...In-loop filters have been comprehensively explored during the development of video coding standards due to their remarkable noise-reduction capabilities.In the early stage of video coding,in-loop filters,such as the deblocking filter,sample adaptive offset,and adaptive loop filter,were performed separately for each component.Recently,cross-component filters have been studied to improve chroma fidelity by exploiting correlations between the luma and chroma channels.This paper introduces the cross-component filters used in the state-ofthe-art video coding standards,including the cross-component adaptive loop filter and cross-component sample adaptive offset.Crosscomponent filters aim to reduce compression artifacts based on the correlation between different components and provide more accurate pixel reconstruction values.We present their origin,development,and status in the current video coding standards.Finally,we conduct discussions on the further evolution of cross-component filters.展开更多
Absorption imaging is a fundamental technique for quantitatively extracting information from ultracold atom experiments.Since ultracold^(6)Li atoms are prepared and detected under high magnetic fields,the suitable det...Absorption imaging is a fundamental technique for quantitatively extracting information from ultracold atom experiments.Since ultracold^(6)Li atoms are prepared and detected under high magnetic fields,the suitable detuning of the probe light can reach the GHz level compared to zero-field imaging.Therefore,based on the energy level structure of^(6)Li atoms and the requirements of subsequent experiments,we design a high-field imaging system with a large frequency range and good robustness,starting from the rationality of the optical layout design and employing offset locking techniques.This imaging system covers the entire crossover region from Bose–Einstein condensate to Bardeen–Cooper–Schrieffer(BEC–BCS)and realizes free switching between zero-field and high-field imaging.Additionally,by introducing a proportionality coefficient to correct for the intensity fluctuations of the probe light,we mitigate its disturbance on the statistical measurement of particle numbers in the experiment.This work not only provides a design reference for other quantum gas experiments requiring absorption imaging under strong bias magnetic fields,but also serves as an important reference for improving the imaging performance.展开更多
The surface velocity is one of the most important characteristics of glaciers.Monitoring and mapping glacier movements are of great significance for the studies of sea-level rise,glacier mass balance and dynamics,glob...The surface velocity is one of the most important characteristics of glaciers.Monitoring and mapping glacier movements are of great significance for the studies of sea-level rise,glacier mass balance and dynamics,global warming,and the management of freshwater resources.It is also essential for the early warnings of hazards caused by ice avalanches.SAR imaging geodesy has been developed for measuring glacier velocity,especially the pixel-offset tracking method.This paper introduces some basic concepts of glaciology and principles of various SAR imaging geodesy methods,with a detailed presentation about the developments in the applications of the pixel-offset tracking method.Finally,the challenges and future prospects of SAR imaging geodesy in glacier monitoring are discussed.展开更多
AIM:To compare the visual and optical outcomes following femtosecond laser in situ keratomileusis(FS-LASIK)using an aberration neutral profile with asymmetric offset(AO)and pupil center(PC)treatments.METHODS:In this r...AIM:To compare the visual and optical outcomes following femtosecond laser in situ keratomileusis(FS-LASIK)using an aberration neutral profile with asymmetric offset(AO)and pupil center(PC)treatments.METHODS:In this randomized double-blind clinical trial study,48(24 cases)and 38 eyes(19 cases)underwent myopic astigmatism and hyperopic astigmatism LASIK.One eye of each individual was randomly assigned to AO centration and the fellow eye underwent the PC-centered method.The clinical outcomes including uncorrected visual acuity(UCVA),best-corrected visual acuity(BCVA),safety and efficacy indexes,subjective spherical equivalent(SE)and corneal high-order aberrations(HOAs)were measured at baseline and 6mo postoperatively.RESULTS:In the myopic group,the mean preoperative SE and astigmatism were-4.12±0.87(-2.88 to-6.00)diopter(D)and-0.88±0.79(0 to-2.75)D,respectively.In the hyperopic group,the mean preoperative SE and astigmatism were 0.93±0.59(-0.25 to 2.25)D and-0.73±1.00(0 to-4.25)D,respectively.At 6mo postoperatively,the safety and efficacy indexes were similar for centration in myopic and hyperopic LASIK groups.In the myopic group,significant changes were found in horizontal trefoil(P=0.041)and oblique trefoil(P=0.031)in favor of AO centration treatment.CONCLUSION:Femtosecond-LASIK is a safe and efficacious procedure for treatment of myopic and hyperopic astigmatism.AO-centered and PC-centered approaches provide similar visual and refractive outcomes.Myopic astigmatism LASIK with AO centration leads to slightly better corneal aberration outcomes.展开更多
Attempts to remove environmentally harmful materials in mass production industries are always a major issue and draw attention if the substitution guarantees a chance to lower fabrication cost and to improve device pe...Attempts to remove environmentally harmful materials in mass production industries are always a major issue and draw attention if the substitution guarantees a chance to lower fabrication cost and to improve device performance,as in a wide bandgap Zn_(1-x)Mg_(x)O(ZMO)to replace the CdS buffer in Cu(In_(1-x),Ga_(x))Se_(2)(CIGSe)thin-film solar cell structure.ZMO is one of the candidates for the buffer material in CIGSe thin-film solar cells with a wide and controllable bandgap depending on the Mg content,which can be helpful in attaining a suitable conduction band offset.Hence,compared to the fixed and limited bandgap of a CdS buffer,a ZMO buffer may provide advantages in V_(oc) and J_(sc) based on its controllable and wide bandgap,even with a relatively wider bandgap CIGSe thin-film solar cell.In addition,to solve problems with the defect sites at the ZMO/CIGSe junction interface,a few-nanometer ZnS layer is employed for heterojunction interface passivation,forming a ZMO/ZnS buffer structure by atomic layer deposition(ALD).Finally,a Cd-free all-dry-processed CIGSe solar cell with a wider bandgap(1.25 eV)and ALD-grown buffer structure exhibited the best power conversion efficiency of 19.1%,which exhibited a higher performance than the CdS counterpart.展开更多
This paper proposes a virtual position-offset injection based permanent magnet temperature estimation approach for permanent magnet synchronous machines(PMSMs). The concept of virtual position-offset injection is math...This paper proposes a virtual position-offset injection based permanent magnet temperature estimation approach for permanent magnet synchronous machines(PMSMs). The concept of virtual position-offset injection is mathematically transforming the machine model to a virtual frame with a position-offset. The virtual frame temperature estimation model is derived to calculate the permanent magnet temperature(PMT) directly from the measurements with computation efficiency. The estimation model involves a combined inductance term, which can simplify the establishment of saturation compensation model with less measurements. Moreover, resistance and inverter distorted terms are cancelled in the estimation model, which can improve the robustness to the winding temperature rise and inverter distortion. The proposed approach can achieve simplified computation in temperature estimation and reduced memory usage in saturation compensation. While existing model-based approaches could be affected by either the need of resistance and inverter information or complex saturation compensation. Experiments are conducted on the test machine to verify the proposed approach under various operating conditions.展开更多
Existing mobile robots mostly use graph search algorithms for path planning,which suffer from relatively low planning efficiency owing to high redundancy and large computational complexity.Due to the limitations of th...Existing mobile robots mostly use graph search algorithms for path planning,which suffer from relatively low planning efficiency owing to high redundancy and large computational complexity.Due to the limitations of the neighborhood search strategy,the robots could hardly obtain the most optimal global path.A global path planning algorithm,denoted as EDG*,is proposed by expanding nodes using a well-designed expanding disconnected graph operator(EDG)in this paper.Firstly,all obstacles are marked and their corners are located through the map pre-processing.Then,the EDG operator is designed to find points in non-obstruction areas to complete the rapid expansion of disconnected nodes.Finally,the EDG*heuristic iterative algorithm is proposed.It selects the candidate node through a specific valuation function and realizes the node expansion while avoiding collision with a minimum offset.Path planning experiments were conducted in a typical indoor environment and on the public dataset CSM.The result shows that the proposed EDG*reduced the planning time by more than 90%and total length of paths reduced by more than 4.6%.Compared to A*,Dijkstra and JPS,EDG*does not show an exponential explosion effect in map size.The EDG*showed better performance in terms of path smoothness,and collision avoidance.This shows that the EDG*algorithm proposed in this paper can improve the efficiency of path planning and enhance path quality.展开更多
Based on the three-dimensional elastic-plastic finite element analysis of the 8"(203.2 mm)drill collar joint,this paper studies the mechanical characteristics of the pin and box of NC56 drill collar joints under ...Based on the three-dimensional elastic-plastic finite element analysis of the 8"(203.2 mm)drill collar joint,this paper studies the mechanical characteristics of the pin and box of NC56 drill collar joints under complex load conditions,as well as the downhole secondary makeup features,and calculates the downhole equivalent impact torque with the relative offset at the shoulder of internal and external threads.On the basis of verifying the correctness of the calculation results by using measured results in Well GT1,the prediction model of the downhole equivalent impact torque is formed and applied in the first extra-deep well with a depth over 10000 m in China(Well SDTK1).The results indicate that under complex loads,the stress distribution in drill collar joints is uneven,with relatively higher von Mises stress at the shoulder and the threads close to the shoulder.For 203.2 mm drill collar joints pre-tightened according to the make-up torque recommended by American Petroleum Institute standards,when the downhole equivalent impact torque exceeds 65 kN·m,the preload balance of the joint is disrupted,leading to secondary make-up of the joint.As the downhole equivalent impact torque increases,the relative offset at the shoulder of internal and external threads increases.The calculation results reveal that there exists significant downhole impact torque in Well SDTK1 with complex loading environment.It is necessary to use double shoulder collar joints to improve the impact torque resistance of the joint or optimize the operating parameters to reduce the downhole impact torque,and effectively prevent drilling tool failure.展开更多
Adults requiring total hip arthroplasty(THA)for childhood disorder sequelae present with shortening,limp,pain,and altered gait.THA,which can be particularly challenging due to altered anatomy,requires careful planning...Adults requiring total hip arthroplasty(THA)for childhood disorder sequelae present with shortening,limp,pain,and altered gait.THA,which can be particularly challenging due to altered anatomy,requires careful planning,assessment,and computed tomography evaluation.Preoperative templating is essential to establish the appropriate acetabular and femoral size.Information regarding neck length and offset is needed to ensure the proper options are available at THA.Hip centre restoration must be planned preoperatively and achieved intraoperatively with appropriate exposure,identification,and stable fixation with optimum-size components.Identifying the actual acetabular floor is essential as changes include altered anatomy,distortion of the margins and version changes.Proximal femur changes include anatomical variation,decreased canal diameter,cortical thickness,changes in anteversion,and metaphyseal and diaphyseal mismatch.Preoperative assessment should consist of limb assessment for variations due to prior surgical procedures.Evaluation of the shortening pattern with the relationship of the lesser trochanter to the teardrop would help identify and plan for subtrochanteric shortening osteotomy,especially in high-riding hips.The surgical approach must ensure adequate exposure and soft tissue release to achieve restoration of the anatomical hip centre.The femoral components may require modularity to enable restoration of anteversion and optimum fixation.展开更多
The levered-dual response(LEDAR)Coulomb-damped system attains near resonant vibration isolation by differential preloads/offsets in linear springs.It takes the advantages of both the preloads/offsets in linear springs...The levered-dual response(LEDAR)Coulomb-damped system attains near resonant vibration isolation by differential preloads/offsets in linear springs.It takes the advantages of both the preloads/offsets in linear springs and the guiderail friction for realizing different levels of vibration isolation.The isolation capacities are investigated on the strategies with both the horizontal and vertical guiderails,with the horizontal rail only,and without guiderails.The compressive preloads generally result in the consumption of most of the initial excitation energy so as to overcome the potential threshold.The isolation onsets at the frequency ratio of 1∓0.095 on the left-hand side(LHS)and the right-hand side(RHS)of the lever are relative to the load plate connector.The observed near resonant isolation thus makes the LEDAR system a candidate for the isolation of the mechanical systems about resonance while opening a path for simultaneous harvesterisolation functions and passive functions at extreme frequencies.展开更多
基金Under the auspices of the Chinese Academy of Engineering Advisory Project(No.2018-XZ-14-03)Key Project of National Natural Science Foundation of China(No.51639001)National Key Basic Research Program of China(No.2013CB430406)
文摘Land-use changes in coastal wetlands have led to a worldwide degradation of marine coastal ecosystems and a loss of the ecological services they provide. Ecological offsetting is a popular strategy and an effective mitigation measure for ecosystems that have been degraded, damaged, or destroyed and is critical for habitats where natural recovery is hindered. However, the current understanding of the theory and practice of ecological offsetting for coastal wetlands is extremely limited in many developing countries. We conducted a review of ecological offsetting for coastal wetlands projects and studies in China in 1979–2017 to explore the application and limitations of ecological offsetting theory. It was found that China's coastal ecological offsetting regime has recently entered a rapidly developing stage, with an increasing number of different types of offsetting projects conducted, but theoretical research lags behind practical applications. Considerable governmental, social, technological and ethical challenges remain to resolve. Coastal ecological offsetting schemes have been inconsistent in meeting conservation objectives or preventing net losses because of the challenges of ensuring they are fully consistent in practice(mainly in-kind offsets) and theory(mainly out-of-kind offsets). Ecological offsetting projects were primarily implemented by government, developers, and non-profit organizations. The available funding of coastal ecological offsetting projects is insufficient, which makes ecological offsetting a risky operation. Therefore, we propose strategies for improvement that integrate the consideration of theoretical and practical challenges in the offsetting process, while providing a scientific basis and directional guidance for the future practice of biodiversity conservation and environmental management.
基金phase-wise achievement of the project B-T-C Paradigm and Application of "Jump-dealing"(Project No.:71272190)funded by the National Natural Science Foundation of China,headed by Professor Yu Li,vice president of Tianjin University of Finance and Economics,director of Center for Economic Analysis of Law and Policy Evaluation and member of Expert Advisory Board of the State Council Anti-monopoly Commission of China
文摘Resale price maintenance(RPM) exerts both positive and negative influences on the market competition.Such duality and the consequent difficulties in presenting evidence have often become highly controversial issues in anti-monopoly law enforcement.We found that in reality,effects of jump-dealing and RPM can offset each other.This paper systematically proposed the offsetting theory of jump-dealing and RPM,and analyzed their policy implications for anti price monopoly,thus providing some simple principles and methods to the law enforcement against vertical price monopoly.This will not only reduce the possible "superfluous actions " in current law enforcement,but also help avoid compounded mistakes due to difficulties of enforcement.
基金Under the auspices of National Natural Science Foundation of China(No.U1901212,51639001)Fund for Innovative Research Group of the National Natural Science Foundation of China(No.51721093)National Key R&D Program of China(No.2017YFC0404505)。
文摘Biodiversity offsetting plays a crucial role in managing the impacts of development on natural habitats. Developers, conservation groups, governments and financial institutions have used biodiversity offsetting to design measurable conservation actions to compensate for significant residual adverse biodiversity impacts arising from development. However, the concepts and methodologies of biodiversity offsetting have rarely been systematically reviewed, and best practices are still lacking. This hinders the development and applications of this field, and makes it difficult for new researchers to learn, develop, and apply biodiversity offsetting. This paper aims to review research progress on biodiversity offsetting during the period of 1992 to 2019. We mainly used bibliometric analysis and social network analysis methods to expose the topic diversity, development and promotion of this research field, and assess collaboration among biodiversity offsetting scholars. Our research identified 1190 records, and revealed that the total number of publications increased rapidly since 2002. The most productive journal, country, and author were Biological Conservation, USA, and Dr. Maron M of University of Queensland, respectively. Co-author analysis identified that the 23 authors most relevant to biodiversity offsetting were involved in a collaboration network. And they were mainly from 30 countries in a collaboration network, and the authors from USA, Australia and the United Kingdom have the most cooperation, which mainly driven by policy related to biodiversity offsetting. Our review shows that biodiversity offsetting research is at an early stage of rapid development with topically diverse and collaborative science domains. The majority of studies focus on terrestrial environments, which makes the implementation of aquatic ecosystem is more difficult. Theoretical problems and the implications of research evolution and social network in biodiversity offsetting are discussed, and further development of the theory and methodologies of biodiversity offsetting and management was recommend.
基金Project supported by the National Natural Science Foundation of China(Nos.12272242 and U1934201)。
文摘Piecewise linear systems are prevalent in engineering practice,and can be categorized into symmetric and asymmetric piecewise linear systems.Considering that symmetry is a special case of asymmetry,it is essential to investigate the broader model,namely the asymmetric piecewise linear system.The traditional averaging method is frequently used for studying nonlinear systems,particularly symmetric piecewise linear systems,with the harmonic response of the oscillator serving as a key prerequisite for calculating steady-state solutions.However,asymmetric systems inherently exhibit nonharmonic,asymmetric responses,rendering the traditional averaging method inapplicable.To overcome this limitation,this paper introduces an improved averaging method tailored for an oscillator characterized by asymmetric gaps and springs.Unlike the traditional method,which assumes a purely harmonic response,the improved averaging method redefines the system response as a superposition of a direct current(DC)term and a first harmonic component.Herein,the DC term can be regarded as the offset induced by model asymmetry.Furthermore,the DC term is treated as a slow variable function of time,with its time derivative assumed to be zero when calculating the steady-state solution,akin to the amplitude and phase in the traditional averaging method.Numerical validation demonstrates that the responses computed in both time and frequency domains with the improved averaging method exhibit greater accuracy compared with those derived from the traditional method.Leveraging these improved results,the study also examines the parameter effect,stability,and bifurcation phenomena within the amplitude-frequency responses.
基金financially supported by the National Natural Science Foundation of China(Grants Nos.41877255,and 52078182).
文摘The tiered geosynthetic-reinforced soil (GRS) walls have been increasingly applied in the high and steep retaining soil structures. However, very little is known about the design method for the tiered GRS wall in practice. This study is aimed at proposing an upper-bound stability analysis method of a tiered GRS wall. The proposed method was firstly validated by the existing results from the centrifuge test and the numerical method, and then a parametric study was performed to investigate the effects of the cohesionless backfill friction angle φ1 and the wall geometric parameters including the offset distance, the total wall height, the batter angle δ, the number of tiers n, and wall height ratio of adjacent tiers on the dimensionless equivalent earth pressure coefficient KT. The analysis results demonstrated that as the φ1 increases, the shear strength of backfill is enhanced and thus the KT or the total reinforcement tensile force decreases, and the KT decreases with the increase of the offset distance at the initial stage and then becomes stable when it reaches a certain critical value. For a fixed offset distance, the KT or the total reinforcement tensile force decreases with the increase of the δ. For the two-tiered GRS walls having the offset distance less than the critical value, the wall with the smaller wall height ratio has a larger KT. Further, the variation of the location of the critical failure surfaces of tiered GRS walls was presented in this study with the variation of the φ1 and the wall geometry.
文摘Due to the neglect of the retrieval of communication parameters(including the symbol rate,the symbol timing offset,and the carrier frequency),the existing non-cooperative communication mode recognizers suffer from the generality ability degradation and severe difficulty in distinguishing a large number of modulation modes,etc.To overcome these drawbacks,this paper proposes an efficient communication mode recognizer consisting of communication parameter estimation,the constellation diagram retrieval,and a classification network.In particular,we define a 2-D symbol synchronization metric to retrieve both the symbol rate and the symbol timing offset,whereas a constellation dispersity annealing procedure is devised to correct the carrier frequency accurately.Owing to the accurate estimation of these crucial parameters,high-regularity constellation maps can be retrieved and thus simplify the subsequent classification work.Numerical results show that the proposed communication mode recognizer acquires higher classification accuracy,stronger anti-noise robustness,and higher applicability of distinguishing multiple types,which presents the proposed scheme with vast applicable potentials in non-cooperative scenarios.
基金financed as part of the project“Development of a methodology for instrumental base formation for analysis and modeling of the spatial socio-economic development of systems based on internal reserves in the context of digitalization”(FSEG-2023-0008).
文摘Artificial intelligence(AI)is transforming the tourism industry and affecting on natural ecology,making it more environmentally friendly,efficient and personalized.In 2025,AI technologies are being actively implemented to reduce the carbon footprint,optimize resources,and improve the travel experience.Here are the key applications of AI in environmentally sustainable smart tourism:AI in smart tourism is not just a technological trend,but a necessity for the sustainable development of the industry.Paper analyses personalized and green travel experience and smart tourism.AI-based applications(Google ARCore)allow tourists to get information about attractions without paper booklets.Virtual tours reduce the need for physical travel by reducing the carbon footprint.Platforms offer routes with minimal impact on nature(for example,hiking trails instead of car tours).Tourists can offset their carbon footprint through AI tools by financing tree planting.The introduction of AI solutions allows combining economic benefits with environmental responsibility,creating a future where travel becomes safer for the planet.Paper confirms idea about sustainable tourism development in developing countries and focus on premium ecotourism.Instead of mass tourism,AI helps promote unique destinations(safaris,diving,ethnographic tours),which increases income with less environmental damage.Smart cities with AI-driven transport and energy-saving solutions make tourism more sustainable.
基金co-supported by the National Natural Science Foundation of China(No.12472332)。
文摘This paper investigates the influence of the spanwise-distributed trailing-edge camber morphing on the dynamic stall characteristics of a finite-span wing at Re=2×10^(5).The mathematical model of the spanwise-distributed trailing-edge camber morphing is established based on Chebyshev polynomials,and the deformed wing surface is modeled by a spline surface according to the rib's morphing in the chordwise direction.The Computational Fluid Dynamics(CFD)method is adopted to obtain flow-field results and aerodynamic forces.The SST-γmodel is introduced and the overset mesh technique is adopted.The numerical results show that the spanwisedistributed trailing-edge morphing obviously changes the aerodynamic and energy transfer characteristics of the dynamic stall.Especially when the phase difference between the trailing-edge motion and the wing pitch is-π/2,the interaction between the three-dimensional(3-D)Leading-Edge Vortex(LEV)and Trailing-Edge Vortex(TEV)is strengthened,and the work done by the aerodynamic force turns negative.This indicates that the trailing-edge deformation has the potential to suppress the oscillation amplitude of stall flutter.We also found that as the trailing-edge camber morphing varies more complexly along the spanwise direction,the suppression effect decreases accordingly.
基金supported by the Science and Technology Innovation Development Program(No.70304901).
文摘Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)is considered to be the most potential light-absorbing material to replace CuInGaSe_(2)(CIGS),but the actual photoelectric conversion efficiency of such cells is much lower than that of CIGS.One of the reasons is the high recombination rate of carriers at the interface.In this paper,in order to reduce the carrier recombination,a new solar cell structure with double absorber layers of Al-doped ZnO(AZO)/intrinsic(i)-ZnO/CdS/CZTS_(x1)Se_(1−x1)(CZTSSe_(1))/CZTS_(x2)Se_(1−x2)(CZTSSe_(2))/Mo was proposed,and the optimal conduction band offsets(CBOs)of CdS/CZTSSe_(1) interface and CZTSSe_(1)/CZTSSe_(2) interface were determined by changing the S ratio in CZTSSe_(1) and CZTSSe_(2),and the effect of thickness of CZTSSe_(1) on the performance of the cell was studied.The efficiencies of the optimized single and double absorber layers reached 17.97%and 23.4%,respectively.Compared with the single absorber layer structure,the proposed structure with double absorber layers has better cell performance.
基金supported in part by National Science Foundation of China under Grant No.62031013PCL-CMCC Foundation for Science and Innovation under Grant No.2024ZY1C0040+1 种基金New Cornerstone Science Foundation for the Xplorer PrizeHigh performance Computing Platform of Peking University。
文摘In-loop filters have been comprehensively explored during the development of video coding standards due to their remarkable noise-reduction capabilities.In the early stage of video coding,in-loop filters,such as the deblocking filter,sample adaptive offset,and adaptive loop filter,were performed separately for each component.Recently,cross-component filters have been studied to improve chroma fidelity by exploiting correlations between the luma and chroma channels.This paper introduces the cross-component filters used in the state-ofthe-art video coding standards,including the cross-component adaptive loop filter and cross-component sample adaptive offset.Crosscomponent filters aim to reduce compression artifacts based on the correlation between different components and provide more accurate pixel reconstruction values.We present their origin,development,and status in the current video coding standards.Finally,we conduct discussions on the further evolution of cross-component filters.
基金supported by the National Natural Science Foundation of China(Grant Nos.92365208 and 11920101004)the National Key Research and Development Program of China(Grant Nos.2021YFA0718300 and 2021YFA1400900).
文摘Absorption imaging is a fundamental technique for quantitatively extracting information from ultracold atom experiments.Since ultracold^(6)Li atoms are prepared and detected under high magnetic fields,the suitable detuning of the probe light can reach the GHz level compared to zero-field imaging.Therefore,based on the energy level structure of^(6)Li atoms and the requirements of subsequent experiments,we design a high-field imaging system with a large frequency range and good robustness,starting from the rationality of the optical layout design and employing offset locking techniques.This imaging system covers the entire crossover region from Bose–Einstein condensate to Bardeen–Cooper–Schrieffer(BEC–BCS)and realizes free switching between zero-field and high-field imaging.Additionally,by introducing a proportionality coefficient to correct for the intensity fluctuations of the probe light,we mitigate its disturbance on the statistical measurement of particle numbers in the experiment.This work not only provides a design reference for other quantum gas experiments requiring absorption imaging under strong bias magnetic fields,but also serves as an important reference for improving the imaging performance.
文摘The surface velocity is one of the most important characteristics of glaciers.Monitoring and mapping glacier movements are of great significance for the studies of sea-level rise,glacier mass balance and dynamics,global warming,and the management of freshwater resources.It is also essential for the early warnings of hazards caused by ice avalanches.SAR imaging geodesy has been developed for measuring glacier velocity,especially the pixel-offset tracking method.This paper introduces some basic concepts of glaciology and principles of various SAR imaging geodesy methods,with a detailed presentation about the developments in the applications of the pixel-offset tracking method.Finally,the challenges and future prospects of SAR imaging geodesy in glacier monitoring are discussed.
基金Supported by Noor Ophthalmology Research Center.
文摘AIM:To compare the visual and optical outcomes following femtosecond laser in situ keratomileusis(FS-LASIK)using an aberration neutral profile with asymmetric offset(AO)and pupil center(PC)treatments.METHODS:In this randomized double-blind clinical trial study,48(24 cases)and 38 eyes(19 cases)underwent myopic astigmatism and hyperopic astigmatism LASIK.One eye of each individual was randomly assigned to AO centration and the fellow eye underwent the PC-centered method.The clinical outcomes including uncorrected visual acuity(UCVA),best-corrected visual acuity(BCVA),safety and efficacy indexes,subjective spherical equivalent(SE)and corneal high-order aberrations(HOAs)were measured at baseline and 6mo postoperatively.RESULTS:In the myopic group,the mean preoperative SE and astigmatism were-4.12±0.87(-2.88 to-6.00)diopter(D)and-0.88±0.79(0 to-2.75)D,respectively.In the hyperopic group,the mean preoperative SE and astigmatism were 0.93±0.59(-0.25 to 2.25)D and-0.73±1.00(0 to-4.25)D,respectively.At 6mo postoperatively,the safety and efficacy indexes were similar for centration in myopic and hyperopic LASIK groups.In the myopic group,significant changes were found in horizontal trefoil(P=0.041)and oblique trefoil(P=0.031)in favor of AO centration treatment.CONCLUSION:Femtosecond-LASIK is a safe and efficacious procedure for treatment of myopic and hyperopic astigmatism.AO-centered and PC-centered approaches provide similar visual and refractive outcomes.Myopic astigmatism LASIK with AO centration leads to slightly better corneal aberration outcomes.
基金conducted under the framework of the research and development program of the Korea Institute of Energy Research(C4-2412 and C4-2413)supported by the National Research Foundation of Korea(grant number 2022M3J1A1063019)funded by the Ministry of Science and ICT.
文摘Attempts to remove environmentally harmful materials in mass production industries are always a major issue and draw attention if the substitution guarantees a chance to lower fabrication cost and to improve device performance,as in a wide bandgap Zn_(1-x)Mg_(x)O(ZMO)to replace the CdS buffer in Cu(In_(1-x),Ga_(x))Se_(2)(CIGSe)thin-film solar cell structure.ZMO is one of the candidates for the buffer material in CIGSe thin-film solar cells with a wide and controllable bandgap depending on the Mg content,which can be helpful in attaining a suitable conduction band offset.Hence,compared to the fixed and limited bandgap of a CdS buffer,a ZMO buffer may provide advantages in V_(oc) and J_(sc) based on its controllable and wide bandgap,even with a relatively wider bandgap CIGSe thin-film solar cell.In addition,to solve problems with the defect sites at the ZMO/CIGSe junction interface,a few-nanometer ZnS layer is employed for heterojunction interface passivation,forming a ZMO/ZnS buffer structure by atomic layer deposition(ALD).Finally,a Cd-free all-dry-processed CIGSe solar cell with a wider bandgap(1.25 eV)and ALD-grown buffer structure exhibited the best power conversion efficiency of 19.1%,which exhibited a higher performance than the CdS counterpart.
基金supported in part by the National Natural Science Foundation of China under Grant 52105079 and 62103455。
文摘This paper proposes a virtual position-offset injection based permanent magnet temperature estimation approach for permanent magnet synchronous machines(PMSMs). The concept of virtual position-offset injection is mathematically transforming the machine model to a virtual frame with a position-offset. The virtual frame temperature estimation model is derived to calculate the permanent magnet temperature(PMT) directly from the measurements with computation efficiency. The estimation model involves a combined inductance term, which can simplify the establishment of saturation compensation model with less measurements. Moreover, resistance and inverter distorted terms are cancelled in the estimation model, which can improve the robustness to the winding temperature rise and inverter distortion. The proposed approach can achieve simplified computation in temperature estimation and reduced memory usage in saturation compensation. While existing model-based approaches could be affected by either the need of resistance and inverter information or complex saturation compensation. Experiments are conducted on the test machine to verify the proposed approach under various operating conditions.
基金Supported by National Key Research and Development Program of China(Grant No.2022YFB4700402).
文摘Existing mobile robots mostly use graph search algorithms for path planning,which suffer from relatively low planning efficiency owing to high redundancy and large computational complexity.Due to the limitations of the neighborhood search strategy,the robots could hardly obtain the most optimal global path.A global path planning algorithm,denoted as EDG*,is proposed by expanding nodes using a well-designed expanding disconnected graph operator(EDG)in this paper.Firstly,all obstacles are marked and their corners are located through the map pre-processing.Then,the EDG operator is designed to find points in non-obstruction areas to complete the rapid expansion of disconnected nodes.Finally,the EDG*heuristic iterative algorithm is proposed.It selects the candidate node through a specific valuation function and realizes the node expansion while avoiding collision with a minimum offset.Path planning experiments were conducted in a typical indoor environment and on the public dataset CSM.The result shows that the proposed EDG*reduced the planning time by more than 90%and total length of paths reduced by more than 4.6%.Compared to A*,Dijkstra and JPS,EDG*does not show an exponential explosion effect in map size.The EDG*showed better performance in terms of path smoothness,and collision avoidance.This shows that the EDG*algorithm proposed in this paper can improve the efficiency of path planning and enhance path quality.
基金Supported by the National Natural Science Foundation of China(52174003,52374008).
文摘Based on the three-dimensional elastic-plastic finite element analysis of the 8"(203.2 mm)drill collar joint,this paper studies the mechanical characteristics of the pin and box of NC56 drill collar joints under complex load conditions,as well as the downhole secondary makeup features,and calculates the downhole equivalent impact torque with the relative offset at the shoulder of internal and external threads.On the basis of verifying the correctness of the calculation results by using measured results in Well GT1,the prediction model of the downhole equivalent impact torque is formed and applied in the first extra-deep well with a depth over 10000 m in China(Well SDTK1).The results indicate that under complex loads,the stress distribution in drill collar joints is uneven,with relatively higher von Mises stress at the shoulder and the threads close to the shoulder.For 203.2 mm drill collar joints pre-tightened according to the make-up torque recommended by American Petroleum Institute standards,when the downhole equivalent impact torque exceeds 65 kN·m,the preload balance of the joint is disrupted,leading to secondary make-up of the joint.As the downhole equivalent impact torque increases,the relative offset at the shoulder of internal and external threads increases.The calculation results reveal that there exists significant downhole impact torque in Well SDTK1 with complex loading environment.It is necessary to use double shoulder collar joints to improve the impact torque resistance of the joint or optimize the operating parameters to reduce the downhole impact torque,and effectively prevent drilling tool failure.
文摘Adults requiring total hip arthroplasty(THA)for childhood disorder sequelae present with shortening,limp,pain,and altered gait.THA,which can be particularly challenging due to altered anatomy,requires careful planning,assessment,and computed tomography evaluation.Preoperative templating is essential to establish the appropriate acetabular and femoral size.Information regarding neck length and offset is needed to ensure the proper options are available at THA.Hip centre restoration must be planned preoperatively and achieved intraoperatively with appropriate exposure,identification,and stable fixation with optimum-size components.Identifying the actual acetabular floor is essential as changes include altered anatomy,distortion of the margins and version changes.Proximal femur changes include anatomical variation,decreased canal diameter,cortical thickness,changes in anteversion,and metaphyseal and diaphyseal mismatch.Preoperative assessment should consist of limb assessment for variations due to prior surgical procedures.Evaluation of the shortening pattern with the relationship of the lesser trochanter to the teardrop would help identify and plan for subtrochanteric shortening osteotomy,especially in high-riding hips.The surgical approach must ensure adequate exposure and soft tissue release to achieve restoration of the anatomical hip centre.The femoral components may require modularity to enable restoration of anteversion and optimum fixation.
基金partially supported by the Nottingham Ningbo China Beacons of Excellence Research and Innovation Institute (No. I01211200001)LDS 2023 Educational Foundation of The University of Nottingham Ningbo China (No. E06221200002)
文摘The levered-dual response(LEDAR)Coulomb-damped system attains near resonant vibration isolation by differential preloads/offsets in linear springs.It takes the advantages of both the preloads/offsets in linear springs and the guiderail friction for realizing different levels of vibration isolation.The isolation capacities are investigated on the strategies with both the horizontal and vertical guiderails,with the horizontal rail only,and without guiderails.The compressive preloads generally result in the consumption of most of the initial excitation energy so as to overcome the potential threshold.The isolation onsets at the frequency ratio of 1∓0.095 on the left-hand side(LHS)and the right-hand side(RHS)of the lever are relative to the load plate connector.The observed near resonant isolation thus makes the LEDAR system a candidate for the isolation of the mechanical systems about resonance while opening a path for simultaneous harvesterisolation functions and passive functions at extreme frequencies.
