The characteristics of tropical cyclone(TC) tilts under vertically varying background flows were preliminarily examined in this study based on numerical simulations with the Tropical Cyclone Model version 4(TCM4).The ...The characteristics of tropical cyclone(TC) tilts under vertically varying background flows were preliminarily examined in this study based on numerical simulations with the Tropical Cyclone Model version 4(TCM4).The tilt magnitudes presented a linearly decreasing tendency in the simulation with the environmental wind speed vertically varying throughout the troposphere and in the simulation with the vertical wind shear concentrated in the lower troposphere,while the vortex tilt showed a linearly increasing tendency in magnitude in the simulation where the vertical shear was concentrated in the upper troposphere.The change in tilt magnitude was found to be related to the evolution of the penetration depth near the eyewall.When the shear was concentrated in the lower troposphere,the vortex tended to tilt downshear right during the early integration and underwent more precession processes.When the shear was concentrated in the upper troposphere,the vortex rapidly tilted downshear left during the early simulation and vortex precession was less frequently observed.The storms simulated in all experiments were finally in downshear-left tilt equilibrium.展开更多
Compositionally undulating step-graded Al（Ga）InxAs （x = 0.05-0.52） buffers with the following InP layer were grown by metal-organic chemical vapor deposition （MOCVD） on （001） GaAs with a 15° miscut. The d...Compositionally undulating step-graded Al（Ga）InxAs （x = 0.05-0.52） buffers with the following InP layer were grown by metal-organic chemical vapor deposition （MOCVD） on （001） GaAs with a 15° miscut. The dislocation dis- tribution and tilts of the epilayers were examined using x-ray rocking curve and （004） reciprocal space maps （RSM） along two orthogonal （110） directions. The results suggested that such reverse-graded layers have different effects on a and 13 dislocations. A higher dislocation density was observed along the [ 110] direction and an epilayer tilt of - 1.43° was attained in the [1-10] direction when a reverse-graded layer strategy was employed. However, for conventional step-graded samples, the dislocation density is normally higher along the [1-10] direction.展开更多
Based on the load model of a uniform isotropic semi-infinite elastic medium,we deduced a calculation of vertical displacement and tilt and proposed a method of calculation of vertical displacements and tilts caused by...Based on the load model of a uniform isotropic semi-infinite elastic medium,we deduced a calculation of vertical displacement and tilt and proposed a method of calculation of vertical displacements and tilts caused by irregular load on the ground or underground at a certain point with two-dimensional and three-dimensional shapes. We compared the difference between the simplified model and the irregular model. Finally,the vertical displacements near the irregular load and the distribution of horizontal tilt are presented.The results show that,compared with the point simplified model,the irregular load model has certain advantages for describing the near field. The establishment of a twodimensional irregular load model can help with the calculation of the modal vector superposition after load scattering. The three-dimensional irregular load model can redistribute load through different weights given to the scattered points after the load scattering,and then obtain displacement with the vector calculation method. The results of vector superposition calculation from the scattered irregular load both in two-dimensions and three-dimensions are all convergent obviously as grids become denser,and it is shown that the calculation method is correct and feasible.展开更多
In this paper,we introduce theτ_([n])-mutations of a class of Koszul algebra and prove that for the Koszul algebra with the global dimension≤n,if its Koszul dual is an admissible(n-1)-translation algebra,then the qu...In this paper,we introduce theτ_([n])-mutations of a class of Koszul algebra and prove that for the Koszul algebra with the global dimension≤n,if its Koszul dual is an admissible(n-1)-translation algebra,then the quiver of endomorphism algebra of n-APR tilting module can be realized byτ_([n])-mutation.展开更多
Nanocrystals have emerged as cutting-edge functional materials benefiting from the increased surface and enhanced coupling of electronic states.High-resolution imaging in transmission electron microscope can provide i...Nanocrystals have emerged as cutting-edge functional materials benefiting from the increased surface and enhanced coupling of electronic states.High-resolution imaging in transmission electron microscope can provide invaluable structural information of crystalline materials,albeit it remains greatly challenging to nanocrystals due to the arduousness of accurate zone axis adjustment.Herein,a homemade software package,called SmartAxis,is developed for rapid yet accurate zone axis alignment of nanocrystals.Incident electron beam tilt is employed as an eccentric goniometer to measure the angular deviation of a crystal to a zone axis,and then serves as a linkage to calculate theαandβtilts of goniometer based on an accurate quantitative relationship.In this way,high-resolution imaging of one identical small Au nanocrystal,as well as electron beam-sensitive MIL-101 metal-organic framework crystals,along multiple zone axes,was performed successfully by using this accurate,time-and electron dose-saving zone axis alignment software package.展开更多
Aiming at the requirement for high-precision tilt monitoring in the field of structural health monitoring(SHM),this paper proposes a sensitivity-enhanced tilt sensor based on a femtosecond fiber Bragg grating(FBG).Fir...Aiming at the requirement for high-precision tilt monitoring in the field of structural health monitoring(SHM),this paper proposes a sensitivity-enhanced tilt sensor based on a femtosecond fiber Bragg grating(FBG).Firstly,structural design of the tilt sensor was conducted based on static mechanics principles.By positioning the FBG away from the beam’s neutral axis,linear strain enhancement in the FBG was achieved,thereby improving sensor sensitivity.The relationship between FBG strain,applied force,and the offset distance from the neutral axis was established,determining the optimal distance corresponding to maximum strain.Based on this optimization scheme,a prototype of the tilt sensor was designed,fabricated,and experimentally tested.Experimental results show that the FBG offset distance yielding maximum sensitivity is 4.4 mm.Within a tilt angle range of−30°to 30°,the sensor achieved a sensitivity of 129.95 pm/°and a linearity of 0.9997.Compared to conventional FBG-based tilt sensors,both sensitivity and linearity were significantly improved.Furthermore,the sensor demonstrated excellent repeatability(error<0.94%),creep resistance(error<0.30%),and temperature stability(error<0.90%).These results demonstrate the sensor’s excellent potential for SHM applications.The sensor has been successfully deployed in an underground pipeline project,conducting long-term monitoring of tilt and deformation in the steel support structures,further proving its value for engineering safety monitoring.展开更多
Known as the House in the Loire,the three-storey building looks like the victim of a flood that once swept it away,but appearances can be misleading.Walking along the Loire River,near the town of Lavau-sur-Loire,you c...Known as the House in the Loire,the three-storey building looks like the victim of a flood that once swept it away,but appearances can be misleading.Walking along the Loire River,near the town of Lavau-sur-Loire,you can see a rather unusual sight-a tilted building located right in the middle of the river.展开更多
Tilting pair is a key concept in the tilting theory.Let F be an additive subfunctor of the functor Ext_(A)^(1)(-,-).In this paper,we introduce the note of n-F-tilting pair,which is a natural generalization of n-tiltin...Tilting pair is a key concept in the tilting theory.Let F be an additive subfunctor of the functor Ext_(A)^(1)(-,-).In this paper,we introduce the note of n-F-tilting pair,which is a natural generalization of n-tilting pair in the sense of Miyahita.Some propositions and a simplified characterization on n-F-tilting pairs are given.展开更多
Observational analyses and convection-permitting simulations are conducted to study an extreme event of damaging surface winds within a bow-shaped squall line over South China.Prevailing explanations for the formation...Observational analyses and convection-permitting simulations are conducted to study an extreme event of damaging surface winds within a bow-shaped squall line over South China.Prevailing explanations for the formation of damaging surface winds were applied to investigate the detailed processes at the mature stage of a squall line in a complicated real-world scenario.It is shown that environmental vertical wind shear was adequately strong to cause a shearing vorticity,and the shearing vorticity was comparable to the baroclinic vorticity by a cold pool.The balance led to strong upward motions at the leading edge of the squall line and brought plenty of rainfall.The descending rainfall cooled the surrounding air and entrained the upper-level cold air downward to the lower level,strengthening the cold pool by excessive evaporation and melting.The cold pool accelerated the propagation speed of the squall line and caused extensive wind damage at the surface.Meanwhile,the horizontal vortex lines at the leading edge of the cold pool were lifted by frontal updrafts and tilted to form the anti-cyclonic vortex at the middle level.This maintained and intensified the rearinflow jet behind the apex of bow echo in association with a notable midlevel pressure gradient.The rear-inflow jet was then transported downward to the surface by descending condensate,leading to damaging winds there.Other factors,such as environmental flows,however,contributed less to the damaging surface winds.展开更多
Background:The risk of internal fixation failure remains relatively high in stable femoral neck fracture(FNF)(Garden I or II).Preoperative sagittal displacement of the femoral head has been proposed as a potential inf...Background:The risk of internal fixation failure remains relatively high in stable femoral neck fracture(FNF)(Garden I or II).Preoperative sagittal displacement of the femoral head has been proposed as a potential influencing factor.This study aimed to evaluate the impact of sagittal displacement on the outcomes of cannulated screw internal fixation(CSIF)in patients with stable FNF(Garden I or II)by reconstructing the axial sagittal oblique plane of the fracture using preoperative computed tomography(CT)imaging.Methods:This study included 167 patients with FNF who underwent CSIF.The sagittal tilt angle of the femoral head(STAFH)was evaluated using three-dimensional CT(3D-CT).The distribution of preoperative STAFH was analyzed,and its independent association with treatment failure was assessed.Treatment failure was defined as the need for revision surgery within 2 years postoperatively due to avascular necrosis,nonunion,or internal fixation failure.Results:Among the 167 patients,9(5.4%)exhibited anterior tilt(AT)of the femoral head,158(94.60%)presented with posterior tilt(PT).A total of 50 patients(29.9%)demonstrated excessive sagittal displacement(AT≥10°or PT≥20°).In the failure group,80.0%of patients had excessive sagittal displacement compared to 28.1%in the healed group.Excessive sagittal displacement was significantly associated with an increased risk of surgical failure(odds ratio:11.953,95%CI:3.656-39.083,p<0.05).Conclusions:In patients with Garden I or II FNF,greater preoperative sagittal displacement of the femoral head was correlated with a higher likelihood of CSIF failure.AT≥10°or PT≥20°were identified as independent predictors of CSIF failure in FNF patients.Nevertheless,these findings still require confirmation through prospective,multi-center clinical trials with large sample sizes.展开更多
Topochemical fluorination introduces significant structural distortions and emerging properties in perovskite oxides via substituting oxygen with fluorine.However,the rapid fluorination process and the similarity betw...Topochemical fluorination introduces significant structural distortions and emerging properties in perovskite oxides via substituting oxygen with fluorine.However,the rapid fluorination process and the similarity between F and O render the O/F site occupation and local lattice evolution during fluorination unclear.Here we investigated the atomic-scale O/F exchange in La2CoO4and quantified the lattice distortion of three ordered structures:La_(2)CoO_(3.5)F,La_(2)CoO_(3)F_(2),and La_(2)CoO_(2.5)F_(3)by utilizing aberration-corrected electron microscopy.Atomic-resolved elemental mapping provides direct evidence for the O/F occupancy in interstitial and apical sites.We revealed that apical F ions induce significant octahedral tilting from 178°to 165°,linearly proportional to the occupancy rate;and cause the obvious change in the fine structure O K edge,meanwhile apical O is exchanged into interstitial sites.The strong octahedral tilt leads to the in-plane elongation of the[CoO_(4)F_(2)]octahedra.These findings elucidate the atomic-scale mechanisms of the entire fluorination process and highlight the significant role of F in tuning the octahedral tilt of functional oxides.展开更多
Tilted metasurface nanostructures,with excellent physical properties and enormous application potential,pose an urgent need for manufacturing methods.Here,electric-field-driven generative-nanoimprinting technique is p...Tilted metasurface nanostructures,with excellent physical properties and enormous application potential,pose an urgent need for manufacturing methods.Here,electric-field-driven generative-nanoimprinting technique is proposed.The electric field applied between the template and the substrate drives the contact,tilting,filling,and holding processes.By accurately controlling the introduced included angle between the flexible template and the substrate,tilted nanostructures with a controllable angle are imprinted onto the substrate,although they are vertical on the template.By flexibly adjusting the electric field intensity and the included angle,large-area uniform-tilted,gradient-tilted,and high-angle-tilted nanostructures are fabricated.In contrast to traditional replication,the morphology of the nanoimprinting structure is extended to customized control.This work provides a cost-effective,efficient,and versatile technology for the fabrication of various large-area tilted metasurface structures.As an illustration,a tilted nanograting with a high coupling efficiency is fabricated and integrated into augmented reality displays,demonstrating superior imaging quality.展开更多
The inherent challenges arising from variations in user-captured viewpoints and object orientation disparities in real-world scenarios pose significant difficulties in establishing robust correspondence relationships ...The inherent challenges arising from variations in user-captured viewpoints and object orientation disparities in real-world scenarios pose significant difficulties in establishing robust correspondence relationships between image pairs.Methods based on geometric transformation estimation usually perform affine transformation of the global image for viewpoint correction,which not only increases the time complexity but also generates a large number of redundant features.To solve this problem,this paper proposes an adaptive affine transformation model(AATM)to achieve robust image matching by dividing special regions with pixel information and employing feature extraction algorithms with different granularities.First,the input image is divided into significant and non-significant regions by an adaptive algorithm.Second,for the salient region,the feature point extraction is accelerated by optimizing the longitude angle sampling algorithm and constructing the affine invariant nonlinear scale space,introducing the Hessian integral image and box filter.Then,for the non-significant region of the weak texture scene through the uniform step sampling algorithm,a dense feature description can be obtained in the weak texture scenes,so that more robust features are extracted for both significant and non-significant regions.The results of extensive experiments on two datasets show that the AATM algorithm outperforms similar algorithms in terms of the number of correctly matched pairs,elapsed time,and root mean square error(RMSE),indicating that the AATM can obtain more robust matches in scenes with large angle tilting and scale transformations.展开更多
This paper presents an innovative and effective control strategy tailored for a deregulated,diversified energy system involving multiple interconnected area.Each area integrates a unique mix of power generation techno...This paper presents an innovative and effective control strategy tailored for a deregulated,diversified energy system involving multiple interconnected area.Each area integrates a unique mix of power generation technologies:Area 1 combines thermal,hydro,and distributed generation;Area 2 utilizes a blend of thermal units,distributed solar technologies(DST),and hydro power;andThird control area hosts geothermal power station alongside thermal power generation unit and hydropower units.The suggested control system employs a multi-layered approach,featuring a blended methodology utilizing the Tilted Integral Derivative controller(TID)and the Fractional-Order Integral method to enhance performance and stability.The parameters of this hybrid TID-FOI controller are finely tuned using an advanced optimization method known as the Walrus Optimization Algorithm(WaOA).Performance analysis reveals that the combined TID-FOI controller significantly outperforms the TID and PID controllers when comparing their dynamic response across various system configurations.The study also incorporates investigation of redox flow batteries within the broader scope of energy storage applications to assess their impact on system performance.In addition,the research explores the controller’s effectiveness under different power exchange scenarios in a deregulated market,accounting for restrictions on generation ramp rates and governor hysteresis effects in dynamic control.To ensure the reliability and resilience of the presented methodology,the system transitions and develops across a broad range of varying parameters and stochastic load fluctuation.To wrap up,the study offers a pioneering control approach-a hybrid TID-FOI controller optimized via the Walrus Optimization Algorithm(WaOA)-designed for enhanced stability and performance in a complex,three-region hybrid energy system functioning within a deregulated framework.展开更多
Aiming at the paddle tilt angle of the spray-blowing agitation composite process,the four-blade stirring and blowing composite desulfurization agitator was chosen as the research object,and the computational fluid dyn...Aiming at the paddle tilt angle of the spray-blowing agitation composite process,the four-blade stirring and blowing composite desulfurization agitator was chosen as the research object,and the computational fluid dynamics numerical simulation was used to investigate the changes in flow field velocity,turbulent kinetic energy magnitude,and distribution caused by the blade tilt angle.Furthermore,the impact of blade tilt angle on the flow fragmentation behavior of individual bubbles and the coalescence process of multiple bubbles at different positions was studied.Under the same stirring and blowing process parameters,with the increase in the blade tilt angle of the agitator,the velocity of the flow field and the average turbulent kinetic energy inside the agitator decreased,and the bubble fragmentation speed decreased while the merging speed accelerated.The turbulent kinetic energy at the agitator bottom was greater when the blade tilt angle was 3.2°compared to when it was 13.2°,while the turbulent kinetic energy at the agitator upper part was relatively smaller.The results for single bubbles represented the state and trajectory of the bubble fragmentation process,and the results for multiple bubbles illustrated the state and trajectory of the bubble aggregation process.展开更多
Pressure and tilt data are jointly inverted to simultaneously map the orientation and dimensions of a hydraulic fracture.The deformation induced by a fracture under internal pressure is modeled using the distributed d...Pressure and tilt data are jointly inverted to simultaneously map the orientation and dimensions of a hydraulic fracture.The deformation induced by a fracture under internal pressure is modeled using the distributed dislocation technique.The planar fracture is represented by four quarter ellipses,joined at the center and sharing semi-axes.This configuration provides a straightforward model for characterizing asymmetric fracture geometry.The inverse problem of mapping the fracture geometry is formulated using the Bayesian probabilistic method,combining the a priori information on the fracture model with updated information from pressure and tilt data.Solving the nonlinear inverse problem is achieved by pseudo-randomly sampling the posterior probability distribution through the Markov chain Monte Carlo method.The resulting posterior probability distribution is then explored to assess uncertainty,resolution,and correlation between model parameters.Numerical experiments are conducted to verify the accuracy and validity of the proposed analysis method in mapping the fracture geometry using synthetic pressure and tilt data.展开更多
BACKGROUND Tooth defects can cause elongation of occlusal teeth,leading to insufficient repair space.The combination of dental implant restoration and orthodontic treatment of oblique adjacent teeth has a significant ...BACKGROUND Tooth defects can cause elongation of occlusal teeth,leading to insufficient repair space.The combination of dental implant restoration and orthodontic treatment of oblique adjacent teeth has a significant therapeutic effect.AIM To explore clinical efficacy,bone density,and follow-up of implant and orthodontic treatment for patients with inclined adjacent teeth.METHODS In total,98 patients with oblique adjacent teeth were randomly assigned to implant restoration combined with orthodontic treatment(group A,n=49)or to receive implant restoration alone(group B,n=49).Changes in alveolar ridge bone density and apical bone density were observed before and after treatment in the two groups.Changes in chewing function and language function were compared between the two groups of patients.Follow-up lasted for 12 mo after repair to observe any adverse reactions in the oral cavity.RESULTS The clinical effective rates of group A and group B were 97.96%and 85.71%,respectively,with group A having a higher clinical effective rate than group B.After treatment,the bone density of the alveolar ridge and apical bone in both groups decreased compared to before treatment,while the chewing and language functions improved.The changes in various indicators in group A were more significant.After treatment,the satisfaction rate of group A(97.96%)was higher than that of group B(79.59%).The incidence of adverse reactions in group A(2.04%)was lower than that in group B(24.49%).CONCLUSION The amalgamation of implant restoration and orthodontic treatment for adjacent tilted teeth demonstrates notable clinical efficacy,diminishes alveolar bone resorption,and fosters patient functional rehabilitation while exhibiting negligible adverse reactions.展开更多
The transmission line tower will be affected by bad weather and artificial subsidence caused by the foundation and other factors in the power transmission.The tower’s tilt and severe deformation will cause the buildi...The transmission line tower will be affected by bad weather and artificial subsidence caused by the foundation and other factors in the power transmission.The tower’s tilt and severe deformation will cause the building to collapse.Many small changes caused the tower’s collapse,but the early staff often could not intuitively notice the changes in the tower’s state.In the current tower online monitoring system,terminal equipment often needs to replace batteries frequently due to premature exhaustion of power.According to the need for real-time measurement of power line tower,this research designed a real-time monitoring device monitoring the transmission tower attitude tilting and foundation state based on the inertial sensor,the acceleration of 3 axis inertial sensor and angular velocity raw data to pole average filtering pre-processing,and then through the complementary filtering algorithm for comprehensive calculation of tilt angle,the system meets the demand for inclined online monitoring of power line poles and towers regarding measurement accuracy,with low cost and power consumption.The optimization multi-sensor cooperative detection and correction measured tilt angle result relative accuracy can reach 1.03%,which has specific promotion and application value since the system has the advantages of unattended and efficient calculation.展开更多
基金jointly supported by the National(Key)Basic Research and Development(973)Program of China(No.2015CB452803)the National Natural Science Foundation of China(Nos.41475058 and 41375068)+1 种基金the Open Project of the State Key Laboratory of Severe Weather(No.2016LASW-B08)the Top-notch Academic Programs Project of Jiangsu Higher Education Institutions(TAPP)
文摘The characteristics of tropical cyclone(TC) tilts under vertically varying background flows were preliminarily examined in this study based on numerical simulations with the Tropical Cyclone Model version 4(TCM4).The tilt magnitudes presented a linearly decreasing tendency in the simulation with the environmental wind speed vertically varying throughout the troposphere and in the simulation with the vertical wind shear concentrated in the lower troposphere,while the vortex tilt showed a linearly increasing tendency in magnitude in the simulation where the vertical shear was concentrated in the upper troposphere.The change in tilt magnitude was found to be related to the evolution of the penetration depth near the eyewall.When the shear was concentrated in the lower troposphere,the vortex tended to tilt downshear right during the early integration and underwent more precession processes.When the shear was concentrated in the upper troposphere,the vortex rapidly tilted downshear left during the early simulation and vortex precession was less frequently observed.The storms simulated in all experiments were finally in downshear-left tilt equilibrium.
基金Project supported by the National Natural Science Foundation of China(Grant No.61376065)
文摘Compositionally undulating step-graded Al（Ga）InxAs （x = 0.05-0.52） buffers with the following InP layer were grown by metal-organic chemical vapor deposition （MOCVD） on （001） GaAs with a 15° miscut. The dislocation dis- tribution and tilts of the epilayers were examined using x-ray rocking curve and （004） reciprocal space maps （RSM） along two orthogonal （110） directions. The results suggested that such reverse-graded layers have different effects on a and 13 dislocations. A higher dislocation density was observed along the [ 110] direction and an epilayer tilt of - 1.43° was attained in the [1-10] direction when a reverse-graded layer strategy was employed. However, for conventional step-graded samples, the dislocation density is normally higher along the [1-10] direction.
基金funded by the Earthquake Tracing Oriented Task of Monitoring and Forecasting Department of China Earthquake Administration in 2015(2015020201):the 12th“Five-year Plan”Science and Technology Support Plan of China(2012BAK19B02)
文摘Based on the load model of a uniform isotropic semi-infinite elastic medium,we deduced a calculation of vertical displacement and tilt and proposed a method of calculation of vertical displacements and tilts caused by irregular load on the ground or underground at a certain point with two-dimensional and three-dimensional shapes. We compared the difference between the simplified model and the irregular model. Finally,the vertical displacements near the irregular load and the distribution of horizontal tilt are presented.The results show that,compared with the point simplified model,the irregular load model has certain advantages for describing the near field. The establishment of a twodimensional irregular load model can help with the calculation of the modal vector superposition after load scattering. The three-dimensional irregular load model can redistribute load through different weights given to the scattered points after the load scattering,and then obtain displacement with the vector calculation method. The results of vector superposition calculation from the scattered irregular load both in two-dimensions and three-dimensions are all convergent obviously as grids become denser,and it is shown that the calculation method is correct and feasible.
文摘In this paper,we introduce theτ_([n])-mutations of a class of Koszul algebra and prove that for the Koszul algebra with the global dimension≤n,if its Koszul dual is an admissible(n-1)-translation algebra,then the quiver of endomorphism algebra of n-APR tilting module can be realized byτ_([n])-mutation.
基金supported by the National Key R&D Program of China(No.2021YFA1501002)Thousand Talents Program for Distinguished Young Scholars.X.Li thanks the National Natural Science Foundation of China(No.22309021).
文摘Nanocrystals have emerged as cutting-edge functional materials benefiting from the increased surface and enhanced coupling of electronic states.High-resolution imaging in transmission electron microscope can provide invaluable structural information of crystalline materials,albeit it remains greatly challenging to nanocrystals due to the arduousness of accurate zone axis adjustment.Herein,a homemade software package,called SmartAxis,is developed for rapid yet accurate zone axis alignment of nanocrystals.Incident electron beam tilt is employed as an eccentric goniometer to measure the angular deviation of a crystal to a zone axis,and then serves as a linkage to calculate theαandβtilts of goniometer based on an accurate quantitative relationship.In this way,high-resolution imaging of one identical small Au nanocrystal,as well as electron beam-sensitive MIL-101 metal-organic framework crystals,along multiple zone axes,was performed successfully by using this accurate,time-and electron dose-saving zone axis alignment software package.
文摘Aiming at the requirement for high-precision tilt monitoring in the field of structural health monitoring(SHM),this paper proposes a sensitivity-enhanced tilt sensor based on a femtosecond fiber Bragg grating(FBG).Firstly,structural design of the tilt sensor was conducted based on static mechanics principles.By positioning the FBG away from the beam’s neutral axis,linear strain enhancement in the FBG was achieved,thereby improving sensor sensitivity.The relationship between FBG strain,applied force,and the offset distance from the neutral axis was established,determining the optimal distance corresponding to maximum strain.Based on this optimization scheme,a prototype of the tilt sensor was designed,fabricated,and experimentally tested.Experimental results show that the FBG offset distance yielding maximum sensitivity is 4.4 mm.Within a tilt angle range of−30°to 30°,the sensor achieved a sensitivity of 129.95 pm/°and a linearity of 0.9997.Compared to conventional FBG-based tilt sensors,both sensitivity and linearity were significantly improved.Furthermore,the sensor demonstrated excellent repeatability(error<0.94%),creep resistance(error<0.30%),and temperature stability(error<0.90%).These results demonstrate the sensor’s excellent potential for SHM applications.The sensor has been successfully deployed in an underground pipeline project,conducting long-term monitoring of tilt and deformation in the steel support structures,further proving its value for engineering safety monitoring.
文摘Known as the House in the Loire,the three-storey building looks like the victim of a flood that once swept it away,but appearances can be misleading.Walking along the Loire River,near the town of Lavau-sur-Loire,you can see a rather unusual sight-a tilted building located right in the middle of the river.
基金Supported by the National Natural Science Foundation of China(Grant No.12101003)the Natural Science Foundation of Anhui Province(Grant No.2108085QA07).
文摘Tilting pair is a key concept in the tilting theory.Let F be an additive subfunctor of the functor Ext_(A)^(1)(-,-).In this paper,we introduce the note of n-F-tilting pair,which is a natural generalization of n-tilting pair in the sense of Miyahita.Some propositions and a simplified characterization on n-F-tilting pairs are given.
基金Research(2020B0301030004)National Natural Science Foundation of China(42275002)+3 种基金Natural Science Foundation of Chongqing(CSTB2022NSCQ-MSX0890)Scientific and Technological Project of Chongqing Meteorological Service(YWJSGG-202124)Key Innovation Team of China Meteorological Administration(CMA2022ZD09)Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(SML2023SP209)。
文摘Observational analyses and convection-permitting simulations are conducted to study an extreme event of damaging surface winds within a bow-shaped squall line over South China.Prevailing explanations for the formation of damaging surface winds were applied to investigate the detailed processes at the mature stage of a squall line in a complicated real-world scenario.It is shown that environmental vertical wind shear was adequately strong to cause a shearing vorticity,and the shearing vorticity was comparable to the baroclinic vorticity by a cold pool.The balance led to strong upward motions at the leading edge of the squall line and brought plenty of rainfall.The descending rainfall cooled the surrounding air and entrained the upper-level cold air downward to the lower level,strengthening the cold pool by excessive evaporation and melting.The cold pool accelerated the propagation speed of the squall line and caused extensive wind damage at the surface.Meanwhile,the horizontal vortex lines at the leading edge of the cold pool were lifted by frontal updrafts and tilted to form the anti-cyclonic vortex at the middle level.This maintained and intensified the rearinflow jet behind the apex of bow echo in association with a notable midlevel pressure gradient.The rear-inflow jet was then transported downward to the surface by descending condensate,leading to damaging winds there.Other factors,such as environmental flows,however,contributed less to the damaging surface winds.
基金supported by the National Natural Science Foundation of China(82422045).
文摘Background:The risk of internal fixation failure remains relatively high in stable femoral neck fracture(FNF)(Garden I or II).Preoperative sagittal displacement of the femoral head has been proposed as a potential influencing factor.This study aimed to evaluate the impact of sagittal displacement on the outcomes of cannulated screw internal fixation(CSIF)in patients with stable FNF(Garden I or II)by reconstructing the axial sagittal oblique plane of the fracture using preoperative computed tomography(CT)imaging.Methods:This study included 167 patients with FNF who underwent CSIF.The sagittal tilt angle of the femoral head(STAFH)was evaluated using three-dimensional CT(3D-CT).The distribution of preoperative STAFH was analyzed,and its independent association with treatment failure was assessed.Treatment failure was defined as the need for revision surgery within 2 years postoperatively due to avascular necrosis,nonunion,or internal fixation failure.Results:Among the 167 patients,9(5.4%)exhibited anterior tilt(AT)of the femoral head,158(94.60%)presented with posterior tilt(PT).A total of 50 patients(29.9%)demonstrated excessive sagittal displacement(AT≥10°or PT≥20°).In the failure group,80.0%of patients had excessive sagittal displacement compared to 28.1%in the healed group.Excessive sagittal displacement was significantly associated with an increased risk of surgical failure(odds ratio:11.953,95%CI:3.656-39.083,p<0.05).Conclusions:In patients with Garden I or II FNF,greater preoperative sagittal displacement of the femoral head was correlated with a higher likelihood of CSIF failure.AT≥10°or PT≥20°were identified as independent predictors of CSIF failure in FNF patients.Nevertheless,these findings still require confirmation through prospective,multi-center clinical trials with large sample sizes.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.52322212,52025025,5225040212474001)the National Key R&D Program of China(Grant Nos.2022YFA1403203 and 2023YFA1406300)。
文摘Topochemical fluorination introduces significant structural distortions and emerging properties in perovskite oxides via substituting oxygen with fluorine.However,the rapid fluorination process and the similarity between F and O render the O/F site occupation and local lattice evolution during fluorination unclear.Here we investigated the atomic-scale O/F exchange in La2CoO4and quantified the lattice distortion of three ordered structures:La_(2)CoO_(3.5)F,La_(2)CoO_(3)F_(2),and La_(2)CoO_(2.5)F_(3)by utilizing aberration-corrected electron microscopy.Atomic-resolved elemental mapping provides direct evidence for the O/F occupancy in interstitial and apical sites.We revealed that apical F ions induce significant octahedral tilting from 178°to 165°,linearly proportional to the occupancy rate;and cause the obvious change in the fine structure O K edge,meanwhile apical O is exchanged into interstitial sites.The strong octahedral tilt leads to the in-plane elongation of the[CoO_(4)F_(2)]octahedra.These findings elucidate the atomic-scale mechanisms of the entire fluorination process and highlight the significant role of F in tuning the octahedral tilt of functional oxides.
基金supported by National Natural Science Foundation of China(No.52025055 and 52275571)Basic Research Operation Fund of China(No.xzy012024024).
文摘Tilted metasurface nanostructures,with excellent physical properties and enormous application potential,pose an urgent need for manufacturing methods.Here,electric-field-driven generative-nanoimprinting technique is proposed.The electric field applied between the template and the substrate drives the contact,tilting,filling,and holding processes.By accurately controlling the introduced included angle between the flexible template and the substrate,tilted nanostructures with a controllable angle are imprinted onto the substrate,although they are vertical on the template.By flexibly adjusting the electric field intensity and the included angle,large-area uniform-tilted,gradient-tilted,and high-angle-tilted nanostructures are fabricated.In contrast to traditional replication,the morphology of the nanoimprinting structure is extended to customized control.This work provides a cost-effective,efficient,and versatile technology for the fabrication of various large-area tilted metasurface structures.As an illustration,a tilted nanograting with a high coupling efficiency is fabricated and integrated into augmented reality displays,demonstrating superior imaging quality.
基金Supported by the National Natural Science Foundation of China(No.61971162,61771186)the Natural Science Foundation of Heilongjiang Province(No.PL2024 F023)+1 种基金the Fundamental Scientific Research Funds of Heilongjiang Province(No.2022-KYYWF-1050)the Open Research Fund of National Mobile Communications Research Laboratory in Southeast University(No.2023D07).
文摘The inherent challenges arising from variations in user-captured viewpoints and object orientation disparities in real-world scenarios pose significant difficulties in establishing robust correspondence relationships between image pairs.Methods based on geometric transformation estimation usually perform affine transformation of the global image for viewpoint correction,which not only increases the time complexity but also generates a large number of redundant features.To solve this problem,this paper proposes an adaptive affine transformation model(AATM)to achieve robust image matching by dividing special regions with pixel information and employing feature extraction algorithms with different granularities.First,the input image is divided into significant and non-significant regions by an adaptive algorithm.Second,for the salient region,the feature point extraction is accelerated by optimizing the longitude angle sampling algorithm and constructing the affine invariant nonlinear scale space,introducing the Hessian integral image and box filter.Then,for the non-significant region of the weak texture scene through the uniform step sampling algorithm,a dense feature description can be obtained in the weak texture scenes,so that more robust features are extracted for both significant and non-significant regions.The results of extensive experiments on two datasets show that the AATM algorithm outperforms similar algorithms in terms of the number of correctly matched pairs,elapsed time,and root mean square error(RMSE),indicating that the AATM can obtain more robust matches in scenes with large angle tilting and scale transformations.
文摘This paper presents an innovative and effective control strategy tailored for a deregulated,diversified energy system involving multiple interconnected area.Each area integrates a unique mix of power generation technologies:Area 1 combines thermal,hydro,and distributed generation;Area 2 utilizes a blend of thermal units,distributed solar technologies(DST),and hydro power;andThird control area hosts geothermal power station alongside thermal power generation unit and hydropower units.The suggested control system employs a multi-layered approach,featuring a blended methodology utilizing the Tilted Integral Derivative controller(TID)and the Fractional-Order Integral method to enhance performance and stability.The parameters of this hybrid TID-FOI controller are finely tuned using an advanced optimization method known as the Walrus Optimization Algorithm(WaOA).Performance analysis reveals that the combined TID-FOI controller significantly outperforms the TID and PID controllers when comparing their dynamic response across various system configurations.The study also incorporates investigation of redox flow batteries within the broader scope of energy storage applications to assess their impact on system performance.In addition,the research explores the controller’s effectiveness under different power exchange scenarios in a deregulated market,accounting for restrictions on generation ramp rates and governor hysteresis effects in dynamic control.To ensure the reliability and resilience of the presented methodology,the system transitions and develops across a broad range of varying parameters and stochastic load fluctuation.To wrap up,the study offers a pioneering control approach-a hybrid TID-FOI controller optimized via the Walrus Optimization Algorithm(WaOA)-designed for enhanced stability and performance in a complex,three-region hybrid energy system functioning within a deregulated framework.
基金supported by the National Natural Science Foundation of China(No.51904069)the Fundamental Research Funds for the Central Universities(No.N2223026)+1 种基金the Development Fund of State Key Laboratory for Clean Utilization of Complex Nonferrous Metal Resources(No.CNMRCUKF2302)the Scientific Research Fund Project of Northeastern University at Qinhuangdao(No.XNY201808).
文摘Aiming at the paddle tilt angle of the spray-blowing agitation composite process,the four-blade stirring and blowing composite desulfurization agitator was chosen as the research object,and the computational fluid dynamics numerical simulation was used to investigate the changes in flow field velocity,turbulent kinetic energy magnitude,and distribution caused by the blade tilt angle.Furthermore,the impact of blade tilt angle on the flow fragmentation behavior of individual bubbles and the coalescence process of multiple bubbles at different positions was studied.Under the same stirring and blowing process parameters,with the increase in the blade tilt angle of the agitator,the velocity of the flow field and the average turbulent kinetic energy inside the agitator decreased,and the bubble fragmentation speed decreased while the merging speed accelerated.The turbulent kinetic energy at the agitator bottom was greater when the blade tilt angle was 3.2°compared to when it was 13.2°,while the turbulent kinetic energy at the agitator upper part was relatively smaller.The results for single bubbles represented the state and trajectory of the bubble fragmentation process,and the results for multiple bubbles illustrated the state and trajectory of the bubble aggregation process.
基金supported by the National Natural Science Foundation of China under Grant Nos.52374033 and U23A20596.
文摘Pressure and tilt data are jointly inverted to simultaneously map the orientation and dimensions of a hydraulic fracture.The deformation induced by a fracture under internal pressure is modeled using the distributed dislocation technique.The planar fracture is represented by four quarter ellipses,joined at the center and sharing semi-axes.This configuration provides a straightforward model for characterizing asymmetric fracture geometry.The inverse problem of mapping the fracture geometry is formulated using the Bayesian probabilistic method,combining the a priori information on the fracture model with updated information from pressure and tilt data.Solving the nonlinear inverse problem is achieved by pseudo-randomly sampling the posterior probability distribution through the Markov chain Monte Carlo method.The resulting posterior probability distribution is then explored to assess uncertainty,resolution,and correlation between model parameters.Numerical experiments are conducted to verify the accuracy and validity of the proposed analysis method in mapping the fracture geometry using synthetic pressure and tilt data.
基金the Review Committee of General Hospital of Central Theater Command(Approval No.05901).
文摘BACKGROUND Tooth defects can cause elongation of occlusal teeth,leading to insufficient repair space.The combination of dental implant restoration and orthodontic treatment of oblique adjacent teeth has a significant therapeutic effect.AIM To explore clinical efficacy,bone density,and follow-up of implant and orthodontic treatment for patients with inclined adjacent teeth.METHODS In total,98 patients with oblique adjacent teeth were randomly assigned to implant restoration combined with orthodontic treatment(group A,n=49)or to receive implant restoration alone(group B,n=49).Changes in alveolar ridge bone density and apical bone density were observed before and after treatment in the two groups.Changes in chewing function and language function were compared between the two groups of patients.Follow-up lasted for 12 mo after repair to observe any adverse reactions in the oral cavity.RESULTS The clinical effective rates of group A and group B were 97.96%and 85.71%,respectively,with group A having a higher clinical effective rate than group B.After treatment,the bone density of the alveolar ridge and apical bone in both groups decreased compared to before treatment,while the chewing and language functions improved.The changes in various indicators in group A were more significant.After treatment,the satisfaction rate of group A(97.96%)was higher than that of group B(79.59%).The incidence of adverse reactions in group A(2.04%)was lower than that in group B(24.49%).CONCLUSION The amalgamation of implant restoration and orthodontic treatment for adjacent tilted teeth demonstrates notable clinical efficacy,diminishes alveolar bone resorption,and fosters patient functional rehabilitation while exhibiting negligible adverse reactions.
基金This work was supported by the National Natural Science Foundation of China(Nos.62172242,51901152)Industry University Cooperation Education Program of the Ministry of Education(No.2020021680113)Shanxi Scholarship Council of China.
文摘The transmission line tower will be affected by bad weather and artificial subsidence caused by the foundation and other factors in the power transmission.The tower’s tilt and severe deformation will cause the building to collapse.Many small changes caused the tower’s collapse,but the early staff often could not intuitively notice the changes in the tower’s state.In the current tower online monitoring system,terminal equipment often needs to replace batteries frequently due to premature exhaustion of power.According to the need for real-time measurement of power line tower,this research designed a real-time monitoring device monitoring the transmission tower attitude tilting and foundation state based on the inertial sensor,the acceleration of 3 axis inertial sensor and angular velocity raw data to pole average filtering pre-processing,and then through the complementary filtering algorithm for comprehensive calculation of tilt angle,the system meets the demand for inclined online monitoring of power line poles and towers regarding measurement accuracy,with low cost and power consumption.The optimization multi-sensor cooperative detection and correction measured tilt angle result relative accuracy can reach 1.03%,which has specific promotion and application value since the system has the advantages of unattended and efficient calculation.
