The conventional acoustic logging interpretation method, which is based on vertical wells that penetrate isotropic formations, is not suitable for horizontal and deviated wells penetrating anisotropic formations. This...The conventional acoustic logging interpretation method, which is based on vertical wells that penetrate isotropic formations, is not suitable for horizontal and deviated wells penetrating anisotropic formations. This unsuitability is because during horizontal and deviated well drilling, cuttings will splash on the well wall or fall into the borehole bottom and form a thin bed of cuttings. In addition, the high velocity layers at different depths and intrinsic anisotropy may affect acoustic logging measurements. In this study, we examine how these factors affect the acoustic wave slowness measured in horizontal and deviated wells that are surrounded by an anisotropic medium using numerical simulation. We use the staggered-grid finite difference method in time domain （FDTD） combined with hybrid-PML. First, we acquire the acoustic slowness using a simulated array logging system, and then, we analyze how various factors affect acoustic slowness measurements and the differences between the effects of these factors. The factors considered are high-velocity layers, thin beds of cuttings, dipping angle, formation thickness, and anisotropy. The simulation results show that these factors affect acoustic wave slowness measurements differently. We observe that when the wavelength is much smaller than the distance between the borehole wall and high velocity layer, the true slowness of the formation could be acquired. When the wavelengths are of the same order （i.e., in the near-field scenarios）, the geometrical acoustics theory is no longer applicable. Furthermore, when a thin bed of cuttings exists at the bottom of the borehole, Fermat＇s principle is still applicable, and true slowness can be acquired. In anisotropic formations, the measured slowness changes with increments in the dipping angle. Finally, for a measurement system with specific spacing, the slowness of a thin target layer can be acquired when the distance covered by the logging tool is sufficiently long. Based on systematical simulations with different dipping angles and anisotropy in homogenous TI media, slowness estimation charts are established to quantitatively determine the slowness at any dipping angle and for any value of the anisotropic ratio. Synthetic examples with different acoustic logging tools and different elastic parameters demonstrate that the acoustic slowness estimation method can be conveniently applied to horizontal and deviated wells in TI formations with high accuracy.展开更多
The equilibrium equations and the functional for tubing buckling in arbitrary straight wells are derived. The entire buckling process of tubing in deviated wells is analyzed for the first time by utilizing the finite ...The equilibrium equations and the functional for tubing buckling in arbitrary straight wells are derived. The entire buckling process of tubing in deviated wells is analyzed for the first time by utilizing the finite element method. The effects of gravity and torques on the buckling are included in the analyses and the calculated results are well compared with existing solutions. It is shown that the buckling only occurs at the lower portion of the tubing where the axial load is the largest, and the contact force of the well, the bending moment of the tubing and the buckling displacement of this portion vary periodically. The buckling spreads upwards from the bit with the increase of axial load. There is no buckling at the upper portion of the tubing where the bending moment is zero. And the contact force of this section increases only slightly with the increase of the axial load. With the increase of the deviation angle, the length of buckling portion and buckling displacement amplitude decrease, the contact force increases with the increase of load at the upper portion and its amplitude decreases at the lower buckling section, the bending moment remains zero at the upper portion and its amplitude decreases at the lower buckling portion. The buckling displacement increases with the increase of the torque, but the increment is very small.展开更多
Dynamic performance on solids flow with water in deviated tubing is essential for the reliability of pump and normal operation of horizontal and directional wells.Compared with coal-water flow in vertical tubing and s...Dynamic performance on solids flow with water in deviated tubing is essential for the reliability of pump and normal operation of horizontal and directional wells.Compared with coal-water flow in vertical tubing and sand-oil flow with high production in deviated tubing,solids deposition with water shows obvious non-symmetric distributions in deviated tubing from simulations and experiments.The mathematical model of two phase flow was developed under coupling conditions of deviated tubing,low flow rate and viscosity based on the kinetic theory of granular flow and first-order discrete scheme.The results show that solid-water stratified flow in deviated tubing can be divided into two zones of suspension bed and the moving bed throughout the flow field.The solid flowing velocity with water is negative and particles slide down at the bottom of moving bed zone.The process of solids flow with water in deviated tubing will produce pressure loss and consume the kinetic energy.The thickness of deposited layer and the flowing velocity of solids flow downward with water at the moving bed zone enhance with the decreased inlet flow rate and the increased particle size,tubing inside diameter(ID)and inclination angle.Solids are easier into suspension from the upper part of moving bed zone to suspension bed zone and more solid particles flow with water towards the tubing outlet with the increase of inlet flowing velocity.The decision is made to reduce the screen width,tubing ID and inclination angle to maintain to be greater than critical deposition velocity in order to prevent solids settling.And it provides the theoretical basis and technical reserves for solid control and offers an effective approach to enhance tubing cleaning in deviated strings.展开更多
Deviated nasal septum is a frequently occurring condition that can cause nasal obstruction in an individual. It may result in permanent changes in the nasal and sinus mucosa because of altered ventilation of the nasal...Deviated nasal septum is a frequently occurring condition that can cause nasal obstruction in an individual. It may result in permanent changes in the nasal and sinus mucosa because of altered ventilation of the nasal cavity. The present study makes an attempt to review its incidence and its associated pathology. Our study involves two groups of patients with 100 patients in each group. The first group consists of patients who are having nasal obstruction as a chief complaint and have deviated nasal septum. The second group consists of patients with either ear or throat complaints without any nasal symptoms, but were noted to have deviation of nasal septum on examination. An analysis was made to determine whether any particular type of deviation is more prone to develop pathology than other types. Our study shows that an “S” shaped deviation is more prone to be associated with ear, nose and throat pathology.展开更多
Background: Over the years, an optimal surgical method for septorhinoplasty in deviated nose as a challenging problem was the one of common interest of plastic surgeon;the purpose of this study is to compare outcomes ...Background: Over the years, an optimal surgical method for septorhinoplasty in deviated nose as a challenging problem was the one of common interest of plastic surgeon;the purpose of this study is to compare outcomes of open and closed methods of septorhinoplasty in patients with deviated noses. Methods: Through a prospective study, we selected seventy patients with deviated nose. Based on their deviation severity, they underwent open or closed septorhinoplasty. Patients were evaluated for deviation angles of nasal bony and cartilage components, nasal projection, nasolabial angle, nasofacial angle, and nasofrontal angle;for which three standard photos were captured pre and postoperatively. Finally the outcomes were analyzed according to their surgical methods. Results: Closed septorhinoplasty could grant a mean 11 degrees correction to nasal bony component and a mean 8.6 degrees correction to cartilage component. That’s while open septorhinoplasty could bring a mean 19.5 degrees deviation correction to the bony component and a mean 12.5 degrees deviation correction to the cartilage component. Cosmetic angles were not improved significantly after the surgery, maybe because of complicated deformities our series of patients had. Conclusion: Open septorhinoplasty resulted in better cosmetic and functional outcomes than the closed method.展开更多
Objective To summarize the experiences of treating secondary,cartilaginous oblique deviated noses and explore an effective technique to improve the clinical efficacy. Methods Through open approach,anterior and inferio...Objective To summarize the experiences of treating secondary,cartilaginous oblique deviated noses and explore an effective technique to improve the clinical efficacy. Methods Through open approach,anterior and inferior margin of quadrangular cartilage was展开更多
A 2.5-dimensional method in frequency wave-number domain is developed to investigate the mode waves in a deviated borehole penetrating a transversely isotropic formation. The phase velocity dispersion characteristics ...A 2.5-dimensional method in frequency wave-number domain is developed to investigate the mode waves in a deviated borehole penetrating a transversely isotropic formation. The phase velocity dispersion characteristics of the fast and slow flexural mode waves excited by a dipole source are computed accurately at various deviation angles for both hard and soft formations. The sensitivities of the flexural mode waves to all elastic constants in a transversely isotropic formation are calculated. Numerical results show that, for a soft formation, the fast flexural mode wave is dominated by c66 at high deviation angles and low frequencies, while the slow flexural mode wave is dominated by c44 at the same conditions. Waveforms in time domain are also presented to support the conclusions.展开更多
We investigate the effect of particle shape on the transportation mechanism in well-drilling using a three-dimensional model that couples computational fluid dynamics （CFD） with the discrete element method （DEM）. ...We investigate the effect of particle shape on the transportation mechanism in well-drilling using a three-dimensional model that couples computational fluid dynamics （CFD） with the discrete element method （DEM）. This numerical method allows us to incorporate the fluid-particle interactions （drag force, contact force, Saffman lift force, Magnus lift force, buoyancy force） using momentum exchange and the non-Newtonian behavior of the fluid. The interactions of particle-particle, particle-wall, and particle-drill pipe are taken into account with the Hertz-Mindlin model. We compare the transport of spheres with non-spherical particles （non-smooth sphere, disc, and cubic） constructed via the multi- sphere method for a range of fluid inlet velocities and drill pipe inclination angles. The simulations are carried out for laboratory-scale drilling configurations. Our results demonstrate good agreement with published experimental data. We evaluate the fluid-particle flow patterns, the particle velocities, and the particle concentration profiles. The results reveal that particle sphericity plays a major role in the fluid-solid interaction. The traditional assumption of an ideal spherical particle may cause inaccurate results.展开更多
In the paper"A numerical investigation of the acoustic mode waves in a deviated borehole penetrating a transversely isotropic formation"by Liu et al.[1]numerical experiments are reported for a dipole sonic l...In the paper"A numerical investigation of the acoustic mode waves in a deviated borehole penetrating a transversely isotropic formation"by Liu et al.[1]numerical experiments are reported for a dipole sonic logging scenario with a deviated borehole penetrating a VTI anisotropic medium.In such a situation it is important to clearly define the meaning of group and phase velocities as this has led to much confusion in the literature as discussed by Miller,Horne and Walsh[2].展开更多
In this paper,we present local functional law of the iterated logarithm for Cs?rg?-Révész type increments of fractional Brownian motion.The results obtained extend works of Gantert[Ann.Probab.,1993,21(2):104...In this paper,we present local functional law of the iterated logarithm for Cs?rg?-Révész type increments of fractional Brownian motion.The results obtained extend works of Gantert[Ann.Probab.,1993,21(2):1045-1049]and Monrad and Rootzén[Probab.Theory Related Fields,1995,101(2):173-192].展开更多
Land surface temperature(LST)is the key variable in land-atmosphere interaction,having an important impact on weather and climate forecasting.However,achieving consistent analysis of LST and the atmosphere in assimila...Land surface temperature(LST)is the key variable in land-atmosphere interaction,having an important impact on weather and climate forecasting.However,achieving consistent analysis of LST and the atmosphere in assimilation is quite challenging.This is because there is limited knowledge about the cross-component background error covariance(BEC)between LST and atmospheric state variables.This study aims to clarify whether there is a relationship between the error of LST and atmospheric variables,and whether this relationship varies spatially and temporally.To this end,the BEC coupled with atmospheric variables and LST was constructed(LST-BEC),and its characteristics were analyzed based on the 2023 mei-yu season.The general characteristics of LST-BEC show that the LST is mainly correlated with the atmospheric temperature and the correlation decreases gradually with a rise in atmospheric height,and the error standard deviation of the LST is noticeably larger than that of the low-level atmospheric temperature.The spatiotemporal characteristics of LST-BEC on the heavy-rain day and light-rain day show that the error correlation and error standard deviation of LST and low-level atmospheric temperature and humidity are closely related to the weather background,and also have obvious diurnal variations.These results provide valuable information for strongly coupled land-atmosphere assimilation.展开更多
To address the issue of coordinated control of multiple hydrogen and battery storage units to suppress the grid-injected power deviation of wind farms,an online optimization strategy for Battery-hydrogen hybrid energy...To address the issue of coordinated control of multiple hydrogen and battery storage units to suppress the grid-injected power deviation of wind farms,an online optimization strategy for Battery-hydrogen hybrid energy storage systems based on measurement feedback is proposed.First,considering the high charge/discharge losses of hydrogen storage and the low energy density of battery storage,an operational optimization objective is established to enable adaptive energy adjustment in the Battery-hydrogen hybrid energy storage system.Next,an online optimization model minimizing the operational cost of the hybrid system is constructed to suppress grid-injected power deviations with satisfying the operational constraints of hydrogen storage and batteries.Finally,utilizing the online measurement of the energy states of hydrogen storage and batteries,an online optimization strategy based on measurement feedback is designed.Case study results show:before and after smoothing the fluctuations in wind power,the time when the power exceeded the upper and lower limits of the grid-injected power accounted for 24.1%and 1.45%of the total time,respectively,the proposed strategy can effectively keep the grid-injected power deviations of wind farms within the allowable range.Hydrogen storage and batteries respectively undertake long-term and short-term charge/discharge tasks,effectively reducing charge/discharge losses of the Battery-hydrogen hybrid energy storage systems and improving its operational efficiency.展开更多
Accuracy allocation is crucial in the accuracy design of machining tools.Current accuracy allocation methods primarily focus on positional deviation,with little consideration for tool direction deviation.To address th...Accuracy allocation is crucial in the accuracy design of machining tools.Current accuracy allocation methods primarily focus on positional deviation,with little consideration for tool direction deviation.To address this issue,we propose a geometric error cost sensitivity-based accuracy allocation method for five-axis machine tools.A geometric error model consisting of 4l error components is constructed based on homogeneous transformation matrices.Volumetric points with positional and tool direction deviations are randomly sampled to evaluate the accuracy of the machine tool.The sensitivity of each error component at these sampling points is analyzed using the Sobol method.To balance the needs of geometric precision and manufacturing cost,a geometric error cost sensitivity function is developed to estimate the required cost.By allocating error components affecting tool direction deviation first and the remaining components second,this allocation scheme ensures that both deviations meet the requirements.We also perform numerical simulation of a BC-type(B-axis and C-axis type)five-axis machine tool to validate the method.The results show that the new allocation scheme reduces the total geometric error cost by 27.8%compared to a uniform allocation scheme,and yields the same positional and tool direction machining accuracies.展开更多
The implementation of long-term shelterbelt programs in the middle reaches of the Yellow River(MRYR),China not only has improved the overall ecological environment,but also has led to the changes of land use pattern,c...The implementation of long-term shelterbelt programs in the middle reaches of the Yellow River(MRYR),China not only has improved the overall ecological environment,but also has led to the changes of land use pattern,causing carbon storage exchanges.However,the relationship between carbon storage and land use change in the MRYR is not concerned,which results in the uncertainty in the simulation of carbon storage in this area.Land use changes directly affect the carbon storage capacity of ecosystems,and as an indicator reflecting the overall state of land use,land use degree has an important relationship with carbon storage.In this study,land use data and the integrated valuation of ecosystem services and trade-offs(InVEST)model were used to assess the trends in land use degree and carbon storage in the MRYR during 1980-2020.The potential impact index and the standard deviation ellipse(SDE)algorithm were applied to quantify and analyze the characteristics of the impact of land use changes on carbon storage.Subsequently,land use transitions that led to carbon storage variations and their spatial variations were determined.The results showed that:(1)the most significant periods of carbon storage changes and land use transitions were observed during 1990-1995 and 1995-2020,with the most changed areas locating in the east of Fenhe River and in northwestern Henan Province;(2)the positive impact of land use degree on carbon storage may be related to the environmental protection measures implemented along the Yellow River,while the negative impact may be associated with the expansion of construction land in plain areas;and(3)the conversion of other land use types to grassland was the primary factor affecting carbon storage changes during 1980-2020.In future land use planning,attention should be given to the direction of grassland conversion,and focus on reasonably limiting the development of construction land.To enhance carbon storage,it will be crucial to increase the area of high-carbon-density land types,such as forest land and grassland under the condition that the area of permanent farmland does not decrease.展开更多
In this paper,large deviations principle(LDP)and moderate deviations principle(MDP)of record numbers in random walks are studied under certain conditions.The results show that the rate functions of LDP and MDP are dif...In this paper,large deviations principle(LDP)and moderate deviations principle(MDP)of record numbers in random walks are studied under certain conditions.The results show that the rate functions of LDP and MDP are different from those of weak record numbers,which are interesting complements of the conclusions by Li and Yao[1].展开更多
In this paper we study the Freidlin-Wentzell's large deviation principle for the following nonlinear fractional stochastic heat equation driven by Gaussian noise∂/∂tu^(ε)=D_(δ)^(α)(t,x)+√εσ(u^(ε)(t,x))W(t,x...In this paper we study the Freidlin-Wentzell's large deviation principle for the following nonlinear fractional stochastic heat equation driven by Gaussian noise∂/∂tu^(ε)=D_(δ)^(α)(t,x)+√εσ(u^(ε)(t,x))W(t,x),(t,x)∈[0,T]×R,where D_(δ)^(α)is a nonlocal fractional differential operator and W is the Gaussian noise which is white in time and behaves as a fractional Brownian motion with Hurst index H satisfying 3-α/4<H<1/2,in the space variable.The weak convergence approach plays an important role.展开更多
In this paper,based on the structure-behavior coupling paradigm,we propose the concept of deviation of central town to describe the geography-market distance between farmers and the central regional town.Using the sur...In this paper,based on the structure-behavior coupling paradigm,we propose the concept of deviation of central town to describe the geography-market distance between farmers and the central regional town.Using the survey data from farmers in a poverty-stricken village in Western China,the impact of deviation of central town on farmers'livelihood strategies is analyzed.The results indicate that farmers exhibit spatial heterogeneity in their livelihood strategies.Those with low deviation show a strong inclination towards working in urban areas,while those with high deviation tend to integrate into rural industries.The deviation of central town influences farmers'livelihood strategies through the information effect,which is also affected by the level of rural infrastructure and public services,labor force structure and assistance policies.The obtained results are expected to provide guidance for promoting the integration of farmers into the urban-rural economic cycle based on sustainable livelihoods and connecting poverty alleviation with rural revitalization.展开更多
Reconstructing three-dimensional(3D)shapes from a single image remains a significant challenge in computer vision due to the inherent ambiguity caused by missing or occluded shape information.Previous studies have pre...Reconstructing three-dimensional(3D)shapes from a single image remains a significant challenge in computer vision due to the inherent ambiguity caused by missing or occluded shape information.Previous studies have predominantly focused on mesh models supervised by multi-view silhouettes.However,such methods are limited in reconstructing fine details.In this study,a 3D mesh model is predicted from a single image,leveraging depth consistency and without requiring viewpoint pose annotations.The model effectively learns strong shape priors that preserve finer structures and accurately predicts view poses from"correlation-supervised"viewpoints.Additionally,standard deviation and Laplacian losses were employed to regulate mesh edge distribution,resulting in more precise reconstructions.Differentiable renderer functions were derived from the 3D mesh to generate depth maps.Compared to conventional approaches,the proposed method provided superior representation of subtle structures.When applied to both synthetic and real-world datasets,the model outperformed existing methods in view-based 3D reconstruction tasks.展开更多
Load deviations between the output of ultra-supercritical(USC)coal-fired power units and automatic generation control(AGC)commands can adversely affect the safe and stable operation of these units and grid load dispat...Load deviations between the output of ultra-supercritical(USC)coal-fired power units and automatic generation control(AGC)commands can adversely affect the safe and stable operation of these units and grid load dispatching.Data-driven diagnostic methods often fail to account for the imbalanced distribution of data samples,leading to reduced classification performance in diagnosing load deviations in USC units.To address the class imbalance issue in USC load deviation datasets,this study proposes a diagnostic method based on the multi-label natural neighbor boundary oversampling technique(MLNaNBDOS).The method is articulated in three phases.Initially,the traditional binary oversampling strategy is improved by constructing a binary multi-label relationship for the load deviations in coal-fired units.Subsequently,an adaptive adjustment of the oversampling factor is implemented to determine the oversampling weight for each sample class.Finally,the generation of new instances is refined by dynamically evaluating the similarity between new cases and natural neighbors through a random factor,ensuring precise control over the instance generation process.In comparisons with nine benchmark methods across three imbalanced USC load deviation datasets,the proposed method demonstrates superior performance on several key evaluation metrics,including Micro-F1,Micro-G-mean,and Hamming Loss,with average values of 0.8497,0.9150,and 0.1503,respectively.These results substantiate the effectiveness of the proposed method in accurately diagnosing the sources of load deviations in USC units.展开更多
基金supported by National Natural Science Foundation of China(No.41204094)Science Foundation of China University of Petroleum,Beijing(No.2462015YQ0506)
文摘The conventional acoustic logging interpretation method, which is based on vertical wells that penetrate isotropic formations, is not suitable for horizontal and deviated wells penetrating anisotropic formations. This unsuitability is because during horizontal and deviated well drilling, cuttings will splash on the well wall or fall into the borehole bottom and form a thin bed of cuttings. In addition, the high velocity layers at different depths and intrinsic anisotropy may affect acoustic logging measurements. In this study, we examine how these factors affect the acoustic wave slowness measured in horizontal and deviated wells that are surrounded by an anisotropic medium using numerical simulation. We use the staggered-grid finite difference method in time domain （FDTD） combined with hybrid-PML. First, we acquire the acoustic slowness using a simulated array logging system, and then, we analyze how various factors affect acoustic slowness measurements and the differences between the effects of these factors. The factors considered are high-velocity layers, thin beds of cuttings, dipping angle, formation thickness, and anisotropy. The simulation results show that these factors affect acoustic wave slowness measurements differently. We observe that when the wavelength is much smaller than the distance between the borehole wall and high velocity layer, the true slowness of the formation could be acquired. When the wavelengths are of the same order （i.e., in the near-field scenarios）, the geometrical acoustics theory is no longer applicable. Furthermore, when a thin bed of cuttings exists at the bottom of the borehole, Fermat＇s principle is still applicable, and true slowness can be acquired. In anisotropic formations, the measured slowness changes with increments in the dipping angle. Finally, for a measurement system with specific spacing, the slowness of a thin target layer can be acquired when the distance covered by the logging tool is sufficiently long. Based on systematical simulations with different dipping angles and anisotropy in homogenous TI media, slowness estimation charts are established to quantitatively determine the slowness at any dipping angle and for any value of the anisotropic ratio. Synthetic examples with different acoustic logging tools and different elastic parameters demonstrate that the acoustic slowness estimation method can be conveniently applied to horizontal and deviated wells in TI formations with high accuracy.
文摘The equilibrium equations and the functional for tubing buckling in arbitrary straight wells are derived. The entire buckling process of tubing in deviated wells is analyzed for the first time by utilizing the finite element method. The effects of gravity and torques on the buckling are included in the analyses and the calculated results are well compared with existing solutions. It is shown that the buckling only occurs at the lower portion of the tubing where the axial load is the largest, and the contact force of the well, the bending moment of the tubing and the buckling displacement of this portion vary periodically. The buckling spreads upwards from the bit with the increase of axial load. There is no buckling at the upper portion of the tubing where the bending moment is zero. And the contact force of this section increases only slightly with the increase of the axial load. With the increase of the deviation angle, the length of buckling portion and buckling displacement amplitude decrease, the contact force increases with the increase of load at the upper portion and its amplitude decreases at the lower buckling section, the bending moment remains zero at the upper portion and its amplitude decreases at the lower buckling portion. The buckling displacement increases with the increase of the torque, but the increment is very small.
基金funded by National Natural Science Foundation of China(Grant No.52074161)National Science and Technology Major Project of China(Grant No.2016ZX05065-001)+2 种基金Taishan Scholar Project of Shandong Province(Grant No.tsqn202211177)Shandong Provincial Plan for Introduction and Cultivation of Young Pioneers in Colleges and Universities(Grant No.2021-QingChuang-30613019)Natural Science Foundation of Shandong Province(Grant No.ZR2022ME173).
文摘Dynamic performance on solids flow with water in deviated tubing is essential for the reliability of pump and normal operation of horizontal and directional wells.Compared with coal-water flow in vertical tubing and sand-oil flow with high production in deviated tubing,solids deposition with water shows obvious non-symmetric distributions in deviated tubing from simulations and experiments.The mathematical model of two phase flow was developed under coupling conditions of deviated tubing,low flow rate and viscosity based on the kinetic theory of granular flow and first-order discrete scheme.The results show that solid-water stratified flow in deviated tubing can be divided into two zones of suspension bed and the moving bed throughout the flow field.The solid flowing velocity with water is negative and particles slide down at the bottom of moving bed zone.The process of solids flow with water in deviated tubing will produce pressure loss and consume the kinetic energy.The thickness of deposited layer and the flowing velocity of solids flow downward with water at the moving bed zone enhance with the decreased inlet flow rate and the increased particle size,tubing inside diameter(ID)and inclination angle.Solids are easier into suspension from the upper part of moving bed zone to suspension bed zone and more solid particles flow with water towards the tubing outlet with the increase of inlet flowing velocity.The decision is made to reduce the screen width,tubing ID and inclination angle to maintain to be greater than critical deposition velocity in order to prevent solids settling.And it provides the theoretical basis and technical reserves for solid control and offers an effective approach to enhance tubing cleaning in deviated strings.
文摘Deviated nasal septum is a frequently occurring condition that can cause nasal obstruction in an individual. It may result in permanent changes in the nasal and sinus mucosa because of altered ventilation of the nasal cavity. The present study makes an attempt to review its incidence and its associated pathology. Our study involves two groups of patients with 100 patients in each group. The first group consists of patients who are having nasal obstruction as a chief complaint and have deviated nasal septum. The second group consists of patients with either ear or throat complaints without any nasal symptoms, but were noted to have deviation of nasal septum on examination. An analysis was made to determine whether any particular type of deviation is more prone to develop pathology than other types. Our study shows that an “S” shaped deviation is more prone to be associated with ear, nose and throat pathology.
文摘Background: Over the years, an optimal surgical method for septorhinoplasty in deviated nose as a challenging problem was the one of common interest of plastic surgeon;the purpose of this study is to compare outcomes of open and closed methods of septorhinoplasty in patients with deviated noses. Methods: Through a prospective study, we selected seventy patients with deviated nose. Based on their deviation severity, they underwent open or closed septorhinoplasty. Patients were evaluated for deviation angles of nasal bony and cartilage components, nasal projection, nasolabial angle, nasofacial angle, and nasofrontal angle;for which three standard photos were captured pre and postoperatively. Finally the outcomes were analyzed according to their surgical methods. Results: Closed septorhinoplasty could grant a mean 11 degrees correction to nasal bony component and a mean 8.6 degrees correction to cartilage component. That’s while open septorhinoplasty could bring a mean 19.5 degrees deviation correction to the bony component and a mean 12.5 degrees deviation correction to the cartilage component. Cosmetic angles were not improved significantly after the surgery, maybe because of complicated deformities our series of patients had. Conclusion: Open septorhinoplasty resulted in better cosmetic and functional outcomes than the closed method.
文摘Objective To summarize the experiences of treating secondary,cartilaginous oblique deviated noses and explore an effective technique to improve the clinical efficacy. Methods Through open approach,anterior and inferior margin of quadrangular cartilage was
基金supported by the National Natural Science Foundation of China(Grant No.11134011)the National R&D Projects for Key Scientific Instruments(Grant No.ZDYZ2012-1-07)the"12th Five-Year Plan"Period for Informatization Project in Supercomputing Key Demonstration,Chinese Academy of Sciences(Grant No.XXH12503-02-02-2(07))
文摘A 2.5-dimensional method in frequency wave-number domain is developed to investigate the mode waves in a deviated borehole penetrating a transversely isotropic formation. The phase velocity dispersion characteristics of the fast and slow flexural mode waves excited by a dipole source are computed accurately at various deviation angles for both hard and soft formations. The sensitivities of the flexural mode waves to all elastic constants in a transversely isotropic formation are calculated. Numerical results show that, for a soft formation, the fast flexural mode wave is dominated by c66 at high deviation angles and low frequencies, while the slow flexural mode wave is dominated by c44 at the same conditions. Waveforms in time domain are also presented to support the conclusions.
文摘We investigate the effect of particle shape on the transportation mechanism in well-drilling using a three-dimensional model that couples computational fluid dynamics （CFD） with the discrete element method （DEM）. This numerical method allows us to incorporate the fluid-particle interactions （drag force, contact force, Saffman lift force, Magnus lift force, buoyancy force） using momentum exchange and the non-Newtonian behavior of the fluid. The interactions of particle-particle, particle-wall, and particle-drill pipe are taken into account with the Hertz-Mindlin model. We compare the transport of spheres with non-spherical particles （non-smooth sphere, disc, and cubic） constructed via the multi- sphere method for a range of fluid inlet velocities and drill pipe inclination angles. The simulations are carried out for laboratory-scale drilling configurations. Our results demonstrate good agreement with published experimental data. We evaluate the fluid-particle flow patterns, the particle velocities, and the particle concentration profiles. The results reveal that particle sphericity plays a major role in the fluid-solid interaction. The traditional assumption of an ideal spherical particle may cause inaccurate results.
文摘In the paper"A numerical investigation of the acoustic mode waves in a deviated borehole penetrating a transversely isotropic formation"by Liu et al.[1]numerical experiments are reported for a dipole sonic logging scenario with a deviated borehole penetrating a VTI anisotropic medium.In such a situation it is important to clearly define the meaning of group and phase velocities as this has led to much confusion in the literature as discussed by Miller,Horne and Walsh[2].
基金Supported by NSFC(Nos.11661025,12161024)Natural Science Foundation of Guangxi(Nos.2020GXNSFAA159118,2021GXNSFAA196045)+2 种基金Guangxi Science and Technology Project(No.Guike AD20297006)Training Program for 1000 Young and Middle-aged Cadre Teachers in Universities of GuangxiNational College Student's Innovation and Entrepreneurship Training Program(No.202110595049)。
文摘In this paper,we present local functional law of the iterated logarithm for Cs?rg?-Révész type increments of fractional Brownian motion.The results obtained extend works of Gantert[Ann.Probab.,1993,21(2):1045-1049]and Monrad and Rootzén[Probab.Theory Related Fields,1995,101(2):173-192].
基金sponsored by the National Natural Science Foundation of China[grant number U2442218]。
文摘Land surface temperature(LST)is the key variable in land-atmosphere interaction,having an important impact on weather and climate forecasting.However,achieving consistent analysis of LST and the atmosphere in assimilation is quite challenging.This is because there is limited knowledge about the cross-component background error covariance(BEC)between LST and atmospheric state variables.This study aims to clarify whether there is a relationship between the error of LST and atmospheric variables,and whether this relationship varies spatially and temporally.To this end,the BEC coupled with atmospheric variables and LST was constructed(LST-BEC),and its characteristics were analyzed based on the 2023 mei-yu season.The general characteristics of LST-BEC show that the LST is mainly correlated with the atmospheric temperature and the correlation decreases gradually with a rise in atmospheric height,and the error standard deviation of the LST is noticeably larger than that of the low-level atmospheric temperature.The spatiotemporal characteristics of LST-BEC on the heavy-rain day and light-rain day show that the error correlation and error standard deviation of LST and low-level atmospheric temperature and humidity are closely related to the weather background,and also have obvious diurnal variations.These results provide valuable information for strongly coupled land-atmosphere assimilation.
基金Supported by State Grid Zhejiang Electric Power Co.,Ltd.Science and Technology Project Funding(No.B311DS230005).
文摘To address the issue of coordinated control of multiple hydrogen and battery storage units to suppress the grid-injected power deviation of wind farms,an online optimization strategy for Battery-hydrogen hybrid energy storage systems based on measurement feedback is proposed.First,considering the high charge/discharge losses of hydrogen storage and the low energy density of battery storage,an operational optimization objective is established to enable adaptive energy adjustment in the Battery-hydrogen hybrid energy storage system.Next,an online optimization model minimizing the operational cost of the hybrid system is constructed to suppress grid-injected power deviations with satisfying the operational constraints of hydrogen storage and batteries.Finally,utilizing the online measurement of the energy states of hydrogen storage and batteries,an online optimization strategy based on measurement feedback is designed.Case study results show:before and after smoothing the fluctuations in wind power,the time when the power exceeded the upper and lower limits of the grid-injected power accounted for 24.1%and 1.45%of the total time,respectively,the proposed strategy can effectively keep the grid-injected power deviations of wind farms within the allowable range.Hydrogen storage and batteries respectively undertake long-term and short-term charge/discharge tasks,effectively reducing charge/discharge losses of the Battery-hydrogen hybrid energy storage systems and improving its operational efficiency.
基金supported by the Key R&D Program of Zhejiang Province(Nos.2023C01166 and 2024SJCZX0046)the Zhejiang Provincial Natural Science Foundation of China(Nos.LDT23E05013E05 and LD24E050009)the Natural Science Foundation of Ningbo(No.2021J150),China.
文摘Accuracy allocation is crucial in the accuracy design of machining tools.Current accuracy allocation methods primarily focus on positional deviation,with little consideration for tool direction deviation.To address this issue,we propose a geometric error cost sensitivity-based accuracy allocation method for five-axis machine tools.A geometric error model consisting of 4l error components is constructed based on homogeneous transformation matrices.Volumetric points with positional and tool direction deviations are randomly sampled to evaluate the accuracy of the machine tool.The sensitivity of each error component at these sampling points is analyzed using the Sobol method.To balance the needs of geometric precision and manufacturing cost,a geometric error cost sensitivity function is developed to estimate the required cost.By allocating error components affecting tool direction deviation first and the remaining components second,this allocation scheme ensures that both deviations meet the requirements.We also perform numerical simulation of a BC-type(B-axis and C-axis type)five-axis machine tool to validate the method.The results show that the new allocation scheme reduces the total geometric error cost by 27.8%compared to a uniform allocation scheme,and yields the same positional and tool direction machining accuracies.
基金funded by the National Natural Science Foundation of China(52079103)the Outstanding Youth Science Fund of Xi'an University of Science and Technology(2024YQ2-02).
文摘The implementation of long-term shelterbelt programs in the middle reaches of the Yellow River(MRYR),China not only has improved the overall ecological environment,but also has led to the changes of land use pattern,causing carbon storage exchanges.However,the relationship between carbon storage and land use change in the MRYR is not concerned,which results in the uncertainty in the simulation of carbon storage in this area.Land use changes directly affect the carbon storage capacity of ecosystems,and as an indicator reflecting the overall state of land use,land use degree has an important relationship with carbon storage.In this study,land use data and the integrated valuation of ecosystem services and trade-offs(InVEST)model were used to assess the trends in land use degree and carbon storage in the MRYR during 1980-2020.The potential impact index and the standard deviation ellipse(SDE)algorithm were applied to quantify and analyze the characteristics of the impact of land use changes on carbon storage.Subsequently,land use transitions that led to carbon storage variations and their spatial variations were determined.The results showed that:(1)the most significant periods of carbon storage changes and land use transitions were observed during 1990-1995 and 1995-2020,with the most changed areas locating in the east of Fenhe River and in northwestern Henan Province;(2)the positive impact of land use degree on carbon storage may be related to the environmental protection measures implemented along the Yellow River,while the negative impact may be associated with the expansion of construction land in plain areas;and(3)the conversion of other land use types to grassland was the primary factor affecting carbon storage changes during 1980-2020.In future land use planning,attention should be given to the direction of grassland conversion,and focus on reasonably limiting the development of construction land.To enhance carbon storage,it will be crucial to increase the area of high-carbon-density land types,such as forest land and grassland under the condition that the area of permanent farmland does not decrease.
基金supported by the National Natural Science Foundation of China(Grant No.11671145)the Science and Technology Commission of Shanghai Municipality(Grant No.18dz2271000).
文摘In this paper,large deviations principle(LDP)and moderate deviations principle(MDP)of record numbers in random walks are studied under certain conditions.The results show that the rate functions of LDP and MDP are different from those of weak record numbers,which are interesting complements of the conclusions by Li and Yao[1].
基金Partially supported by NSFC(No.11701304)the K.C.Wong Education Foundation。
文摘In this paper we study the Freidlin-Wentzell's large deviation principle for the following nonlinear fractional stochastic heat equation driven by Gaussian noise∂/∂tu^(ε)=D_(δ)^(α)(t,x)+√εσ(u^(ε)(t,x))W(t,x),(t,x)∈[0,T]×R,where D_(δ)^(α)is a nonlocal fractional differential operator and W is the Gaussian noise which is white in time and behaves as a fractional Brownian motion with Hurst index H satisfying 3-α/4<H<1/2,in the space variable.The weak convergence approach plays an important role.
文摘In this paper,based on the structure-behavior coupling paradigm,we propose the concept of deviation of central town to describe the geography-market distance between farmers and the central regional town.Using the survey data from farmers in a poverty-stricken village in Western China,the impact of deviation of central town on farmers'livelihood strategies is analyzed.The results indicate that farmers exhibit spatial heterogeneity in their livelihood strategies.Those with low deviation show a strong inclination towards working in urban areas,while those with high deviation tend to integrate into rural industries.The deviation of central town influences farmers'livelihood strategies through the information effect,which is also affected by the level of rural infrastructure and public services,labor force structure and assistance policies.The obtained results are expected to provide guidance for promoting the integration of farmers into the urban-rural economic cycle based on sustainable livelihoods and connecting poverty alleviation with rural revitalization.
基金Supported by National Key Research and Development Program of China(Grant No.2024YFB3409800)Postdoctoral Fellowship Program of CPSF of China(Grant No.GZB20240940)China Postdoctoral Science Foundation(Grant Nos.2025T181108,2024M764127)。
文摘Reconstructing three-dimensional(3D)shapes from a single image remains a significant challenge in computer vision due to the inherent ambiguity caused by missing or occluded shape information.Previous studies have predominantly focused on mesh models supervised by multi-view silhouettes.However,such methods are limited in reconstructing fine details.In this study,a 3D mesh model is predicted from a single image,leveraging depth consistency and without requiring viewpoint pose annotations.The model effectively learns strong shape priors that preserve finer structures and accurately predicts view poses from"correlation-supervised"viewpoints.Additionally,standard deviation and Laplacian losses were employed to regulate mesh edge distribution,resulting in more precise reconstructions.Differentiable renderer functions were derived from the 3D mesh to generate depth maps.Compared to conventional approaches,the proposed method provided superior representation of subtle structures.When applied to both synthetic and real-world datasets,the model outperformed existing methods in view-based 3D reconstruction tasks.
基金supported by the National Natural Science Foundation of China(Grant No.62173050)Shenzhen Municipal Science and Technology Innovation Committee(Grant No.KCXFZ20211020165004006)+3 种基金Natural Science Foundation of Hunan Province of China(Grant No.2023JJ30051)Hunan Provincial Graduate Student Research Innovation Project(Grant No.QL20230214)Major Scientific and Technological Innovation Platform Project of Hunan Province(2024JC1003)Hunan Provincial University Students’Energy Conservation and Emission Reduction Innovation and Entrepreneurship Education Center(Grant No.2019-10).
文摘Load deviations between the output of ultra-supercritical(USC)coal-fired power units and automatic generation control(AGC)commands can adversely affect the safe and stable operation of these units and grid load dispatching.Data-driven diagnostic methods often fail to account for the imbalanced distribution of data samples,leading to reduced classification performance in diagnosing load deviations in USC units.To address the class imbalance issue in USC load deviation datasets,this study proposes a diagnostic method based on the multi-label natural neighbor boundary oversampling technique(MLNaNBDOS).The method is articulated in three phases.Initially,the traditional binary oversampling strategy is improved by constructing a binary multi-label relationship for the load deviations in coal-fired units.Subsequently,an adaptive adjustment of the oversampling factor is implemented to determine the oversampling weight for each sample class.Finally,the generation of new instances is refined by dynamically evaluating the similarity between new cases and natural neighbors through a random factor,ensuring precise control over the instance generation process.In comparisons with nine benchmark methods across three imbalanced USC load deviation datasets,the proposed method demonstrates superior performance on several key evaluation metrics,including Micro-F1,Micro-G-mean,and Hamming Loss,with average values of 0.8497,0.9150,and 0.1503,respectively.These results substantiate the effectiveness of the proposed method in accurately diagnosing the sources of load deviations in USC units.
