Objective:To observe the clinical effect of articular cavity injection combined with bite splint therapy for the treatment of anterior disc displacement without reduction(ADDWoR).Methods:The research subjects for this...Objective:To observe the clinical effect of articular cavity injection combined with bite splint therapy for the treatment of anterior disc displacement without reduction(ADDWoR).Methods:The research subjects for this study were 30 patients with ADDWoR treated in the temporomandibular joint specialist outpatient clinic from November 2018 to November 2019,with a disease duration of 1 to 6 months.The treatment group was treated with an articular cavity injection of sodium hyaluronate+bite splint.The control group was treated with a simple articular cavity injection of sodium hyaluronate.The two groups were followed up once every 2 weeks to evaluate the treatment effect and observe the clinical efficacy of the two groups.Statistical analysis was carried out using SPSS 24.0.t-test and general linear regression analysis were carried out to compare the data of both groups,andχ^(2)-test and binary logistic regression analysis were performed for pain index comparison.Results:There was no significant difference in terms of the efficacy of the treatment received by both groups.The mouth opening and joint pain of patients in both groups were significantly improved after treatment(P<0.001).Conclusion:Articular cavity injection of sodium hyaluronate and occlusal splint therapy are both effective and safe methods for treating ADDWoR.展开更多
Anterior repositioning splint(ARS)therapy is considered one of the most effective therapies for treating disc displacement-related temporomandibular disorders(TMDs),which account for a large proportion of TMD cases.Ow...Anterior repositioning splint(ARS)therapy is considered one of the most effective therapies for treating disc displacement-related temporomandibular disorders(TMDs),which account for a large proportion of TMD cases.Owing to the wide application of this therapy,the exact mechanism of remission has increasingly drawn attention.Given that practitioners have different views on ARS therapy,its indications are broadened,and operating methods diverged.This review attempts to provide an overview of ARS therapy and helps practitioners establish indications and suitable operating methods.Representative views in the past 10 years were summarised,and conclusions were drawn as follows:The mechanism of ARS therapy is mainly attributed to internal derangement correction,improvement of stress distribution and recently reported joint remodeling.It has an evident effect in the short term,and the most prevalent operating methods are protruding the mandible to the edge-to-edge position and wearing the ARS for 24 hours daily for 3-6 months.However,long-term stability is not optimal,and thus indications should be selected carefully.Notably,most of the clinical studies in this field are case analyses with low-quality evidence.Well-designed RCTs are required to further validate relevant theories.展开更多
Posterior disc displacement of the temporomandibular joint is rare. We present a unique treatment method and magnetic resonance (MR) images of this condition. The patient was a 43-year-old male with a chief complaint ...Posterior disc displacement of the temporomandibular joint is rare. We present a unique treatment method and magnetic resonance (MR) images of this condition. The patient was a 43-year-old male with a chief complaint of abnormal occlusion. Regarding the present status, there was no occlusion on the right side. No temporomandibular joint pain, myalgia, or clicking were observed while mouth opening. On MR images, the posterior disc displacement without reduction on the right was observed and it was assumed that occlusal abnormality was due to this condition. We treated him with the following methods. After injection into the superior articular cavity with 2% lidocaine, a sodium hyaluronate preparation was injected followed by intermaxillary traction applied using rubber. The recovery of occlusion was confirmed in follow-up at 5 days after treatment. In the 13th days, the intermaxillary traction was removed. On MR images, the right disc condition was changed to anterior disc displacement with reduction. We consider our treatment methods are effective for this clinical condition.展开更多
In the case of reverse drag of normal faulting, the displacement and horizontal extension are determined based on the established equations for the three mechanisms: rigid body, vertical shear and inclined shear. Ther...In the case of reverse drag of normal faulting, the displacement and horizontal extension are determined based on the established equations for the three mechanisms: rigid body, vertical shear and inclined shear. There are three sub-cases of basal detachment for the rigid body model: horizontal detachment, antithetic detachment and synthetic detachment. For the rigid body model, the established equations indicate that the total displacement on the synthetic base (D<sub>t2</sub>) is the largest, that on the horizontal base (D<sub>t1</sub>) is moderate, and that on the antithetic base (D<sub>t3</sub>) is the smallest. On the other hand, the value of (D<sub>t1</sub>) is larger than the displacement for the vertical shear (D<sub>t4</sub>). The value of (D<sub>t1</sub>) is larger than or less than the displacement for the inclined shear (D<sub>t5</sub>) depending on the original fault dip δ<sub>0</sub>, bedding angle θ, and the angle of shear direction β. For all original parameters, the value of D<sub>t5</sub> is less than the value of D<sub>t4</sub>. Also, by comparing three rotation mechanisms, we find that the inclined shear produces largest extension, the rigid body model with horizontal detachment produces the smallest extension, and the vertical shear model produces moderate extension.展开更多
The copper disc casting machine is core equipment for producing copper anode plates in the copper metallurgy industry.The copper disc casting machine casting package motion curve(CPMC) is significant for precise casti...The copper disc casting machine is core equipment for producing copper anode plates in the copper metallurgy industry.The copper disc casting machine casting package motion curve(CPMC) is significant for precise casting and efficient production.However,the lack of exact casting modeling and real-time simulation information severely restricts dynamic CPMC optimization.To this end,a liquid copper droplet model describes the casting package copper flow pattern in the casting process.Furthermore,a CPMC optimization model is proposed for the first time.On top of this,a digital twin dual closed-loop self-optimization application framework(DT-DCS) is constructed for optimizing the copper disc casting process to achieve self-optimization of the CPMC and closed-loop feedback of manufacturing information during the casting process.Finally,a case study is carried out based on the proposed methods in the industrial field.展开更多
A gas puff imaging(GPI)diagnostic has been developed and operated on EAST since 2012,and the time-delay estimation(TDE)method is used to derive the propagation velocity of fluctuations from the two-dimensional GPI dat...A gas puff imaging(GPI)diagnostic has been developed and operated on EAST since 2012,and the time-delay estimation(TDE)method is used to derive the propagation velocity of fluctuations from the two-dimensional GPI data.However,with the TDE method it is difficult to analyze the data with fast transient events,such as edge-localized mode(ELM).Consequently,a method called the spatial displacement estimation(SDE)algorithm is developed to estimate the turbulence velocity with high temporal resolution.Based on the SDE algorithm,we make some improvements,including an adaptive median filter and super-resolution technology.After the development of the algorithm,a straight-line movement and a curved-line movement are used to test the accuracy of the algorithm,and the calculated speed agrees well with preset speed.This SDE algorithm is applied to the EAST GPI data analysis,and the derived propagation velocity of turbulence is consistent with that from the TDE method,but with much higher temporal resolution.展开更多
The estimation of residual displacements in a structure due to an anticipated earthquake event has increasingly become an important component of performance-based earthquake engineering because controlling these displ...The estimation of residual displacements in a structure due to an anticipated earthquake event has increasingly become an important component of performance-based earthquake engineering because controlling these displacements plays an important role in ensuring cost-feasible or cost-effective repairs in a damaged structure after the event.An attempt is made in this study to obtain statistical estimates of constant-ductility residual displacement spectra for bilinear and pinching oscillators with 5%initial damping,directly in terms of easily available seismological,site,and model parameters.None of the available models for the bilinear and pinching oscillators are useful when design spectra for a seismic hazard at a site are not available.The statistical estimates of a residual displacement spectrum are proposed in terms of earthquake magnitude,epicentral distance,site geology parameter,and three model parameters for a given set of ductility demand and a hysteretic energy capacity coefficient in the case of bilinear and pinching models,as well as for a given set of pinching parameters for displacement and strength at the breakpoint in the case of pinching model alone.The proposed scaling model is applicable to horizontal ground motions in the western U.S.for earthquake magnitudes less than 7 or epicentral distances greater than 20 km.展开更多
The electrochemical CO_(2) reduction reaction(CO_(2)RR) to controllable chemicals is considered as a promising pathway to store intermittent renewable energy. Herein, a set of catalysts based on copper-nitrogendoped c...The electrochemical CO_(2) reduction reaction(CO_(2)RR) to controllable chemicals is considered as a promising pathway to store intermittent renewable energy. Herein, a set of catalysts based on copper-nitrogendoped carbon xerogel(Cu-N-C) are successfully developed varying the copper amount and the nature of the copper precursor, for the efficient CO_(2)RR. The electrocatalytic performance of Cu-N-C materials is assessed by a rotating ring-disc electrode(RRDE), technique still rarely explored for CO_(2)RR. For comparison, products are also characterized by online gas chromatography in a H-cell. The as-synthesized Cu-NC catalysts are found to be active and highly CO selective at low overpotentials(from -0.6 to -0.8 V vs.RHE) in 0.1 M KHCO_(3), while H_(2) from the competitive water reduction appears at larger overpotentials(-0.9 V vs. RHE). The optimum copper acetate-derived catalyst containing Cu-N_(4) moieties exhibits a CO_(2)-to-CO turnover frequency of 997 h^(-1) at -0.9 V vs. RHE with a H_(2)/CO ratio of 1.8. These results demonstrate that RRDE configuration can be used as a feasible approach for identifying electrolysis products from CO_(2)RR.展开更多
AIM:To compare superficial and deep vascular properties of optic discs between crowded discs and controls using optical coherence tomography angiography(OCT-A).METHODS:Thirty patients with crowded discs,and 47 control...AIM:To compare superficial and deep vascular properties of optic discs between crowded discs and controls using optical coherence tomography angiography(OCT-A).METHODS:Thirty patients with crowded discs,and 47 control subjects were enrolled in the study.One eye of each individual was included and OCT-A scans of optic discs were obtained in a 4.5×4.5 mm^(2) rectangular area.Radial peripapillary capillary(RPC)density,peripapillary retinal nerve fiber layer(pRNFL)thickness,cup volume,rim area,disc area,cup-to-disc(c/d)area ratio,and vertical c/d ratio were obtained automatically using device software.Automated parapapillary choroidal microvasculature(PPCMv)density was calculated using MATLAB software.When the vertical c/d ratio of the optic disc was absent or small cup,it was considered as a crowded disc.RESULTS:The mean signal strength index of OCT-A images was similar between the crowded discs and control eyes(P=0.740).There was no difference in pRNFL between the two groups(P=0.102).There were no differences in RPC density in whole image(P=0.826)and peripapillary region(P=0.923),but inside disc RPC density was higher in crowded optic discs(P=0.003).The PPCMv density in the inner-hemisuperior region was also lower in crowded discs(P=0.026).The pRNFL thickness was positively correlated with peripapillary RPC density(r=0.498,P<0.001).The inside disc RPC density was negatively correlated with c/d area ratio(r=-0.341,P=0.002).CONCLUSION:The higher inside disc RPC density and lower inner-hemisuperior PPCMv density are found in eyes with crowded optic discs.展开更多
Introduction: Lumbar disc herniation (LDH) refers to the rupture of the fibrous annulus of the intervertebral discs. Lumbar curvature may lead to the occurrence of lumbar disc degeneration. Fear of movement may worsen...Introduction: Lumbar disc herniation (LDH) refers to the rupture of the fibrous annulus of the intervertebral discs. Lumbar curvature may lead to the occurrence of lumbar disc degeneration. Fear of movement may worsen their disc herniation and cause further pain and injury. LDH conditions impact the individuals’ quality of life, to explore the relationship between lumbar curve, muscle strength, fear of movement and functional disability among patients with LDH. Methods: An electronic search was conducted on PubMed, Medline, Science Direct, Springerlink, Google Scholar and a hand search from reference lists was reviewed. Publications were included in human studies, patients 25 - 85 years of age, original studies and published in English language journals from January 2002 to December 2023. Result: In total, 64 articles were researched through the online search engines, and 9 papers were found through manual searches of reference lists. As a result, a total of 11 articles were included for the purpose of this review. The comprehensive analysis revealed the presence of eight cross-sectional studies, two retrospective studies and one experimental study. A minimum of 25 participants and a maximum of 360 participants were included. Ten studies included both genders, only one studies included healthy adults and patients with LDH but these studies didn’t mention gender. Results showed that the factors influencing LDH can be categorized into non-modifiable factors, such as gender, age, height or others. Modifiable factors included increased BMI, DM, smoking, alcohol, employment status, lifestyle and health problems or psychology. Conclusion: Females with greater VASC may be at risk of LDH. The lumbar extensor muscles indicated a localized disc herniation or nerve root pathology in patients with LDH. The fear of movement may lead to psychological consequences and reduce functional disability among patients with LDH.展开更多
An extended displacement discontinuity method (EDDM) is proposed to analyze the stress wave propagation in jointed viscoelastic rock mass (VRM).The discontinuities in a rock mass are divided into two groups.The primar...An extended displacement discontinuity method (EDDM) is proposed to analyze the stress wave propagation in jointed viscoelastic rock mass (VRM).The discontinuities in a rock mass are divided into two groups.The primary group with an average geometrical size larger than or in the same order of magnitude of wavelength of a concerned stress wave is defined as "macro-joints",while the secondary group with a high density and relatively small geometrical size compared to the wavelength is known as "micro-defects".The rock mass with micro-defects is modeled as an equivalent viscoelastic medium while the macro-joints in the rock mass are modeled explicitly as physical discontinuities.Viscoelastic properties of a micro-defected sedimentary rock are obtained by longitudinally impacting a cored long sedimentary rod with a pendulum.Wave propagation coefficient and dynamic viscoelastic modulus are measured.The EDDM is then successfully employed to analyze the wave propagation across macro-joint in VRM.The effect of the rock viscosity on the stress wave propagation is evaluated by comparing the results of VRM from the presented EDDM with those of an elastic rock mass (ERM) from the conventional displacement discontinuity method (CDDM).The CDDM is a special case of the EDDM under the condition that the rock viscosity is ignored.Comparison of the reflected and transmitted waves shows that the essential rock viscosity has a significant effect on stress wave attenuation.When a short propagation distance of a stress wave is considered,the results obtained from the CDDM approximate to the EDDM solutions,however,when the propagation distance is sufficiently long relative to the wavelength,the effect of rock viscosity on the stress wave propagation cannot be ignored.展开更多
An efficient time stepping procedure is proposed to treat the system describing compressible miscible displacement in a porous medium by employing a mixed finite element method to approximate the pressure and the flui...An efficient time stepping procedure is proposed to treat the system describing compressible miscible displacement in a porous medium by employing a mixed finite element method to approximate the pressure and the fluid velocity and a standard Galerkin method to approximate the concentration. An extension of the Darcy velocity along Gauss lines is used in the evaluation of the coefficients in the Galerkin procedure for the concentration. These results show that the total algorithm has the superconvergence property of the fluid velocity.展开更多
The present research is focused on the numerical crack coalescence analysis of the micro-cracks and cracks produced during the cutting action of TBM disc cutters. The linear elastic fracture mechanics(LEFM) concepts a...The present research is focused on the numerical crack coalescence analysis of the micro-cracks and cracks produced during the cutting action of TBM disc cutters. The linear elastic fracture mechanics(LEFM) concepts and the maximum tangential stress criterion are used to investigate the micro crack propagation and its direction underneath the excavating discs. A higher order displacement discontinuity method with quadratic displacement discontinuity elements is used to estimate the stress intensity factors near the crack tips. Rock cutting mechanisms under single and double type discs are simulated by the proposed numerical method.The main purposes of the present modeling are to simulate the chip formation process of indented rocks by single and double discs.The effects of specific disc parameters(except speed) on the thrust force Ft, the rolling force Fr, and the specific energy ES are investigated. It has been shown that the specific energy(energy required to cut through a unit volume of rock) of the double disc is less than that of the single disc. Crack propagation in rocks under disc cutters is numerically modeled and the optimum ratio of disc spacing S to penetration depth Pd(i.e. S/Pd ratio) of about 10 is obtained, which is in good agreement with the theoretical and experimental results cited in the literature.展开更多
The higher order displacement discontinuity method(HODDM) utilizing special crack tip elements has been used in the solution of linear elastic fracture mechanics(LEFM) problems. The paper has selected several example ...The higher order displacement discontinuity method(HODDM) utilizing special crack tip elements has been used in the solution of linear elastic fracture mechanics(LEFM) problems. The paper has selected several example problems from the fracture mechanics literature(with available analytical solutions) including center slant crack in an infinite and finite body, single and double edge cracks, cracks emanating from a circular hole. The numerical values of Mode Ⅰ and Mode Ⅱ SIFs for these problems using HODDM are in excellent agreement with analytical results(reaching up to 0.001% deviation from their analytical results). The HODDM is also compared with the XFEM and a modified XFEM results. The results show that the HODDM needs a considerably lower computational effort(with less than 400 nodes) than the XFEM and the modified XFEM(which needs more than 10000 nodes) to reach a much higher accuracy. The proposed HODDM offers higher accuracy and lower computation effort for a wide range of problems in LEFM.展开更多
Background The urokinase plasminogen activator system is believed to play an important role in degradation of the extracellular matrix associated with cartilage and bone destruction; however its precise roles in tempo...Background The urokinase plasminogen activator system is believed to play an important role in degradation of the extracellular matrix associated with cartilage and bone destruction; however its precise roles in temporomandibular disorders have not yet been clarified. The aims of this study were to investigate the gene expression of fibrinolytic factors urokinase plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) in the articular cartilage of rabbit temporomandibular joint (TMJ) with disc displacement (DD) and to probe the relationship between fibrinolytic activity and cartilage remodeling. Methods Disc displacement of right joints was performed in 36 of 78 rabbits under investigation. The animals were sacrificed at 4 days and 1, 2, 4, 8 and 12 weeks after surgery, respectively. The right joints of these animals were harvested and processed for the examination of mRNA expression of uPA and PAI-1 in articular cartilage using in situ hybridization techniques. Results The expression of uPA and PAI-1 was co-expressed weakly in the chondrocytes from transitive zone to hypertrophic zone and mineralized zone, while no hybridizing signals were shown in proliferative zone and superficial zone in control rabbits. The most striking was the up-regulation of uPA and PAI-1 mRNA in 4-day rabbits postoperatively at the onset of cartilage degeneration. The strongest hybridizing signals for uPA and PAI-1 were seen in 2-week rabbits postoperatively. After 2 weeks, the expression of uPA and PAI-1 began to decrease and reached nearly normal level at 12 weeks. Conclusions The expression of the uPA/PAI-1 system coincides with the pathological changes in condylar cartilage after DD. The uPA/PAI-1 system may be one of the essential mediators in articular cartilage remodeling.展开更多
Recently,a disruptive idea was reported about the discovery of a new type of battery named Liquid Displacement Battery(LDB)comprising liquid metal electrodes and molten salt electrolyte.This cell featured a novel conc...Recently,a disruptive idea was reported about the discovery of a new type of battery named Liquid Displacement Battery(LDB)comprising liquid metal electrodes and molten salt electrolyte.This cell featured a novel concept of a porous electronically conductive faradaic membrane instead of the traditional ion-selective ceramic membrane.LDBs are attractive for stationary storage applications but need mitigation against self-discharge.In the instant battery chemistry,Li|LiCl-PbCl_(2)|Pb,reducing the diffusion coefficient of lead ions can be a way forward and a solution can be the addition of Pb O to the electrolyte.The latter acts as a supplementary barrier and complements the function of the faradaic membrane.The remedial actions improved the cell’s coulombic efficiency from 92%to 97%without affecting the voltage efficiency.In addition,the limiting current density of a 500 m Ah cell increased from 575 to 831 m A cm;and the limiting power from 2.53 to 3.66 W.Finally,the effect of Pb O on the impedance and polarization of the cell was also studied.展开更多
A method for topological optimization of structures with discrete variables subjected to dynamic stress and displacement constraints is presented. By using the quasi_static method, the structure optimization problem u...A method for topological optimization of structures with discrete variables subjected to dynamic stress and displacement constraints is presented. By using the quasi_static method, the structure optimization problem under dynamic stress and displacement constraints is converted into one subjected to static stress and displacement constraints. The comprehensive algorithm for topological optimization of structures with discrete variables is used to find the optimum solution.展开更多
The degenerative disease of the intervertebral disc is nowadays an important health problem,which has still not been understood and solved adequately.The vertebral endplate is regarded as one of the vital elements in ...The degenerative disease of the intervertebral disc is nowadays an important health problem,which has still not been understood and solved adequately.The vertebral endplate is regarded as one of the vital elements in the structure of the intervertebral disc.Its constituent cells,the chondrocytes in the endplate,may also be involved in the process of the intervertebral disc degeneration and their role is central both under physiological and pathological conditions.They main functions include a role in homeostasis of the extracellular environment of the intervertebral disc,metabolic support and nutrition of the discal nucleus and annulus beneath and the preservation of the extracellular matrix.Therefore,it is understandable that the cells in the endplate have been in the centre of research from several viewpoints,such as development,degeneration and growth,reparation and remodelling,as well as treatment strategies.In this article,we briefly review the importance of vertebral endplate,which are often overlooked,in the intervertebral disc degeneration.展开更多
文摘Objective:To observe the clinical effect of articular cavity injection combined with bite splint therapy for the treatment of anterior disc displacement without reduction(ADDWoR).Methods:The research subjects for this study were 30 patients with ADDWoR treated in the temporomandibular joint specialist outpatient clinic from November 2018 to November 2019,with a disease duration of 1 to 6 months.The treatment group was treated with an articular cavity injection of sodium hyaluronate+bite splint.The control group was treated with a simple articular cavity injection of sodium hyaluronate.The two groups were followed up once every 2 weeks to evaluate the treatment effect and observe the clinical efficacy of the two groups.Statistical analysis was carried out using SPSS 24.0.t-test and general linear regression analysis were carried out to compare the data of both groups,andχ^(2)-test and binary logistic regression analysis were performed for pain index comparison.Results:There was no significant difference in terms of the efficacy of the treatment received by both groups.The mouth opening and joint pain of patients in both groups were significantly improved after treatment(P<0.001).Conclusion:Articular cavity injection of sodium hyaluronate and occlusal splint therapy are both effective and safe methods for treating ADDWoR.
文摘Anterior repositioning splint(ARS)therapy is considered one of the most effective therapies for treating disc displacement-related temporomandibular disorders(TMDs),which account for a large proportion of TMD cases.Owing to the wide application of this therapy,the exact mechanism of remission has increasingly drawn attention.Given that practitioners have different views on ARS therapy,its indications are broadened,and operating methods diverged.This review attempts to provide an overview of ARS therapy and helps practitioners establish indications and suitable operating methods.Representative views in the past 10 years were summarised,and conclusions were drawn as follows:The mechanism of ARS therapy is mainly attributed to internal derangement correction,improvement of stress distribution and recently reported joint remodeling.It has an evident effect in the short term,and the most prevalent operating methods are protruding the mandible to the edge-to-edge position and wearing the ARS for 24 hours daily for 3-6 months.However,long-term stability is not optimal,and thus indications should be selected carefully.Notably,most of the clinical studies in this field are case analyses with low-quality evidence.Well-designed RCTs are required to further validate relevant theories.
文摘Posterior disc displacement of the temporomandibular joint is rare. We present a unique treatment method and magnetic resonance (MR) images of this condition. The patient was a 43-year-old male with a chief complaint of abnormal occlusion. Regarding the present status, there was no occlusion on the right side. No temporomandibular joint pain, myalgia, or clicking were observed while mouth opening. On MR images, the posterior disc displacement without reduction on the right was observed and it was assumed that occlusal abnormality was due to this condition. We treated him with the following methods. After injection into the superior articular cavity with 2% lidocaine, a sodium hyaluronate preparation was injected followed by intermaxillary traction applied using rubber. The recovery of occlusion was confirmed in follow-up at 5 days after treatment. In the 13th days, the intermaxillary traction was removed. On MR images, the right disc condition was changed to anterior disc displacement with reduction. We consider our treatment methods are effective for this clinical condition.
文摘In the case of reverse drag of normal faulting, the displacement and horizontal extension are determined based on the established equations for the three mechanisms: rigid body, vertical shear and inclined shear. There are three sub-cases of basal detachment for the rigid body model: horizontal detachment, antithetic detachment and synthetic detachment. For the rigid body model, the established equations indicate that the total displacement on the synthetic base (D<sub>t2</sub>) is the largest, that on the horizontal base (D<sub>t1</sub>) is moderate, and that on the antithetic base (D<sub>t3</sub>) is the smallest. On the other hand, the value of (D<sub>t1</sub>) is larger than the displacement for the vertical shear (D<sub>t4</sub>). The value of (D<sub>t1</sub>) is larger than or less than the displacement for the inclined shear (D<sub>t5</sub>) depending on the original fault dip δ<sub>0</sub>, bedding angle θ, and the angle of shear direction β. For all original parameters, the value of D<sub>t5</sub> is less than the value of D<sub>t4</sub>. Also, by comparing three rotation mechanisms, we find that the inclined shear produces largest extension, the rigid body model with horizontal detachment produces the smallest extension, and the vertical shear model produces moderate extension.
基金supported in part by the National Major Scientific Research Equipment of China (61927803)the National Natural Science Foundation of China Basic Science Center Project (61988101)+1 种基金Science and Technology Innovation Program of Hunan Province (2021RC4054)the China Postdoctoral Science Foundation (2021M691681)。
文摘The copper disc casting machine is core equipment for producing copper anode plates in the copper metallurgy industry.The copper disc casting machine casting package motion curve(CPMC) is significant for precise casting and efficient production.However,the lack of exact casting modeling and real-time simulation information severely restricts dynamic CPMC optimization.To this end,a liquid copper droplet model describes the casting package copper flow pattern in the casting process.Furthermore,a CPMC optimization model is proposed for the first time.On top of this,a digital twin dual closed-loop self-optimization application framework(DT-DCS) is constructed for optimizing the copper disc casting process to achieve self-optimization of the CPMC and closed-loop feedback of manufacturing information during the casting process.Finally,a case study is carried out based on the proposed methods in the industrial field.
基金supported by the National Magnetic Confinement Fusion Energy R&D Program of China(Nos.2022YFE03030001,2022YFE03020004 and 2022YFE 03050003)National Natural Science Foundation of China(Nos.12275310,11975275,12175277 and 11975271)+2 种基金the Science Foundation of Institute of Plasma Physics,Chinese Academy of Sciences(No.DSJJ-2021-01)the Collaborative Innovation Program of Hefei Science Center,Chinese Academy of Sciences(No.2021HSC-CIP019)the Users with Excellence Program of Hefei Science Center,Chinese Academy of Sciences(Nos.2021HSC-UE014 and 2021HSCUE012)。
文摘A gas puff imaging(GPI)diagnostic has been developed and operated on EAST since 2012,and the time-delay estimation(TDE)method is used to derive the propagation velocity of fluctuations from the two-dimensional GPI data.However,with the TDE method it is difficult to analyze the data with fast transient events,such as edge-localized mode(ELM).Consequently,a method called the spatial displacement estimation(SDE)algorithm is developed to estimate the turbulence velocity with high temporal resolution.Based on the SDE algorithm,we make some improvements,including an adaptive median filter and super-resolution technology.After the development of the algorithm,a straight-line movement and a curved-line movement are used to test the accuracy of the algorithm,and the calculated speed agrees well with preset speed.This SDE algorithm is applied to the EAST GPI data analysis,and the derived propagation velocity of turbulence is consistent with that from the TDE method,but with much higher temporal resolution.
文摘The estimation of residual displacements in a structure due to an anticipated earthquake event has increasingly become an important component of performance-based earthquake engineering because controlling these displacements plays an important role in ensuring cost-feasible or cost-effective repairs in a damaged structure after the event.An attempt is made in this study to obtain statistical estimates of constant-ductility residual displacement spectra for bilinear and pinching oscillators with 5%initial damping,directly in terms of easily available seismological,site,and model parameters.None of the available models for the bilinear and pinching oscillators are useful when design spectra for a seismic hazard at a site are not available.The statistical estimates of a residual displacement spectrum are proposed in terms of earthquake magnitude,epicentral distance,site geology parameter,and three model parameters for a given set of ductility demand and a hysteretic energy capacity coefficient in the case of bilinear and pinching models,as well as for a given set of pinching parameters for displacement and strength at the breakpoint in the case of pinching model alone.The proposed scaling model is applicable to horizontal ground motions in the western U.S.for earthquake magnitudes less than 7 or epicentral distances greater than 20 km.
基金Grant PID2020-115848RB-C21 "STORELEC" projectTED2021-129694B-C22 "DEFY-CO2" project funded by MCIN/AEI/10.13039/501100011033+3 种基金LMP253_ (2)1 project funded by Gobierno de AragónGrant IJC2019-041874-I funded by the MCIN/AEI/10.13039/501100011033CSIC for her JAE Intro ICU 2021-ICB-04 grantthe Y2020/EMT-6419 "CEOTRES" project funded by the Comunidad Autonoma de Madrid。
文摘The electrochemical CO_(2) reduction reaction(CO_(2)RR) to controllable chemicals is considered as a promising pathway to store intermittent renewable energy. Herein, a set of catalysts based on copper-nitrogendoped carbon xerogel(Cu-N-C) are successfully developed varying the copper amount and the nature of the copper precursor, for the efficient CO_(2)RR. The electrocatalytic performance of Cu-N-C materials is assessed by a rotating ring-disc electrode(RRDE), technique still rarely explored for CO_(2)RR. For comparison, products are also characterized by online gas chromatography in a H-cell. The as-synthesized Cu-NC catalysts are found to be active and highly CO selective at low overpotentials(from -0.6 to -0.8 V vs.RHE) in 0.1 M KHCO_(3), while H_(2) from the competitive water reduction appears at larger overpotentials(-0.9 V vs. RHE). The optimum copper acetate-derived catalyst containing Cu-N_(4) moieties exhibits a CO_(2)-to-CO turnover frequency of 997 h^(-1) at -0.9 V vs. RHE with a H_(2)/CO ratio of 1.8. These results demonstrate that RRDE configuration can be used as a feasible approach for identifying electrolysis products from CO_(2)RR.
文摘AIM:To compare superficial and deep vascular properties of optic discs between crowded discs and controls using optical coherence tomography angiography(OCT-A).METHODS:Thirty patients with crowded discs,and 47 control subjects were enrolled in the study.One eye of each individual was included and OCT-A scans of optic discs were obtained in a 4.5×4.5 mm^(2) rectangular area.Radial peripapillary capillary(RPC)density,peripapillary retinal nerve fiber layer(pRNFL)thickness,cup volume,rim area,disc area,cup-to-disc(c/d)area ratio,and vertical c/d ratio were obtained automatically using device software.Automated parapapillary choroidal microvasculature(PPCMv)density was calculated using MATLAB software.When the vertical c/d ratio of the optic disc was absent or small cup,it was considered as a crowded disc.RESULTS:The mean signal strength index of OCT-A images was similar between the crowded discs and control eyes(P=0.740).There was no difference in pRNFL between the two groups(P=0.102).There were no differences in RPC density in whole image(P=0.826)and peripapillary region(P=0.923),but inside disc RPC density was higher in crowded optic discs(P=0.003).The PPCMv density in the inner-hemisuperior region was also lower in crowded discs(P=0.026).The pRNFL thickness was positively correlated with peripapillary RPC density(r=0.498,P<0.001).The inside disc RPC density was negatively correlated with c/d area ratio(r=-0.341,P=0.002).CONCLUSION:The higher inside disc RPC density and lower inner-hemisuperior PPCMv density are found in eyes with crowded optic discs.
文摘Introduction: Lumbar disc herniation (LDH) refers to the rupture of the fibrous annulus of the intervertebral discs. Lumbar curvature may lead to the occurrence of lumbar disc degeneration. Fear of movement may worsen their disc herniation and cause further pain and injury. LDH conditions impact the individuals’ quality of life, to explore the relationship between lumbar curve, muscle strength, fear of movement and functional disability among patients with LDH. Methods: An electronic search was conducted on PubMed, Medline, Science Direct, Springerlink, Google Scholar and a hand search from reference lists was reviewed. Publications were included in human studies, patients 25 - 85 years of age, original studies and published in English language journals from January 2002 to December 2023. Result: In total, 64 articles were researched through the online search engines, and 9 papers were found through manual searches of reference lists. As a result, a total of 11 articles were included for the purpose of this review. The comprehensive analysis revealed the presence of eight cross-sectional studies, two retrospective studies and one experimental study. A minimum of 25 participants and a maximum of 360 participants were included. Ten studies included both genders, only one studies included healthy adults and patients with LDH but these studies didn’t mention gender. Results showed that the factors influencing LDH can be categorized into non-modifiable factors, such as gender, age, height or others. Modifiable factors included increased BMI, DM, smoking, alcohol, employment status, lifestyle and health problems or psychology. Conclusion: Females with greater VASC may be at risk of LDH. The lumbar extensor muscles indicated a localized disc herniation or nerve root pathology in patients with LDH. The fear of movement may lead to psychological consequences and reduce functional disability among patients with LDH.
文摘An extended displacement discontinuity method (EDDM) is proposed to analyze the stress wave propagation in jointed viscoelastic rock mass (VRM).The discontinuities in a rock mass are divided into two groups.The primary group with an average geometrical size larger than or in the same order of magnitude of wavelength of a concerned stress wave is defined as "macro-joints",while the secondary group with a high density and relatively small geometrical size compared to the wavelength is known as "micro-defects".The rock mass with micro-defects is modeled as an equivalent viscoelastic medium while the macro-joints in the rock mass are modeled explicitly as physical discontinuities.Viscoelastic properties of a micro-defected sedimentary rock are obtained by longitudinally impacting a cored long sedimentary rod with a pendulum.Wave propagation coefficient and dynamic viscoelastic modulus are measured.The EDDM is then successfully employed to analyze the wave propagation across macro-joint in VRM.The effect of the rock viscosity on the stress wave propagation is evaluated by comparing the results of VRM from the presented EDDM with those of an elastic rock mass (ERM) from the conventional displacement discontinuity method (CDDM).The CDDM is a special case of the EDDM under the condition that the rock viscosity is ignored.Comparison of the reflected and transmitted waves shows that the essential rock viscosity has a significant effect on stress wave attenuation.When a short propagation distance of a stress wave is considered,the results obtained from the CDDM approximate to the EDDM solutions,however,when the propagation distance is sufficiently long relative to the wavelength,the effect of rock viscosity on the stress wave propagation cannot be ignored.
文摘An efficient time stepping procedure is proposed to treat the system describing compressible miscible displacement in a porous medium by employing a mixed finite element method to approximate the pressure and the fluid velocity and a standard Galerkin method to approximate the concentration. An extension of the Darcy velocity along Gauss lines is used in the evaluation of the coefficients in the Galerkin procedure for the concentration. These results show that the total algorithm has the superconvergence property of the fluid velocity.
文摘The present research is focused on the numerical crack coalescence analysis of the micro-cracks and cracks produced during the cutting action of TBM disc cutters. The linear elastic fracture mechanics(LEFM) concepts and the maximum tangential stress criterion are used to investigate the micro crack propagation and its direction underneath the excavating discs. A higher order displacement discontinuity method with quadratic displacement discontinuity elements is used to estimate the stress intensity factors near the crack tips. Rock cutting mechanisms under single and double type discs are simulated by the proposed numerical method.The main purposes of the present modeling are to simulate the chip formation process of indented rocks by single and double discs.The effects of specific disc parameters(except speed) on the thrust force Ft, the rolling force Fr, and the specific energy ES are investigated. It has been shown that the specific energy(energy required to cut through a unit volume of rock) of the double disc is less than that of the single disc. Crack propagation in rocks under disc cutters is numerically modeled and the optimum ratio of disc spacing S to penetration depth Pd(i.e. S/Pd ratio) of about 10 is obtained, which is in good agreement with the theoretical and experimental results cited in the literature.
文摘The higher order displacement discontinuity method(HODDM) utilizing special crack tip elements has been used in the solution of linear elastic fracture mechanics(LEFM) problems. The paper has selected several example problems from the fracture mechanics literature(with available analytical solutions) including center slant crack in an infinite and finite body, single and double edge cracks, cracks emanating from a circular hole. The numerical values of Mode Ⅰ and Mode Ⅱ SIFs for these problems using HODDM are in excellent agreement with analytical results(reaching up to 0.001% deviation from their analytical results). The HODDM is also compared with the XFEM and a modified XFEM results. The results show that the HODDM needs a considerably lower computational effort(with less than 400 nodes) than the XFEM and the modified XFEM(which needs more than 10000 nodes) to reach a much higher accuracy. The proposed HODDM offers higher accuracy and lower computation effort for a wide range of problems in LEFM.
文摘Background The urokinase plasminogen activator system is believed to play an important role in degradation of the extracellular matrix associated with cartilage and bone destruction; however its precise roles in temporomandibular disorders have not yet been clarified. The aims of this study were to investigate the gene expression of fibrinolytic factors urokinase plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) in the articular cartilage of rabbit temporomandibular joint (TMJ) with disc displacement (DD) and to probe the relationship between fibrinolytic activity and cartilage remodeling. Methods Disc displacement of right joints was performed in 36 of 78 rabbits under investigation. The animals were sacrificed at 4 days and 1, 2, 4, 8 and 12 weeks after surgery, respectively. The right joints of these animals were harvested and processed for the examination of mRNA expression of uPA and PAI-1 in articular cartilage using in situ hybridization techniques. Results The expression of uPA and PAI-1 was co-expressed weakly in the chondrocytes from transitive zone to hypertrophic zone and mineralized zone, while no hybridizing signals were shown in proliferative zone and superficial zone in control rabbits. The most striking was the up-regulation of uPA and PAI-1 mRNA in 4-day rabbits postoperatively at the onset of cartilage degeneration. The strongest hybridizing signals for uPA and PAI-1 were seen in 2-week rabbits postoperatively. After 2 weeks, the expression of uPA and PAI-1 began to decrease and reached nearly normal level at 12 weeks. Conclusions The expression of the uPA/PAI-1 system coincides with the pathological changes in condylar cartilage after DD. The uPA/PAI-1 system may be one of the essential mediators in articular cartilage remodeling.
基金financially supported by the research unit of Group Sadoway Laboratory,Department of Materials Science and Engineering,Massachusetts Institute of Technology,77 Massachusetts Avenue,Cambridge,MA,02139-4307,United Statesthe Portuguese Foundation for Science and Technology(FCT)for his Ph.D.scholarship(PD/BD/128041/2016)+2 种基金financially supported by the Base Funding(UIDB/00511/2020)of the Laboratory for Process Engineering,Environment,Biotechnology and Energy–LEPABEfunded by national funds through the FCT/MCTES(PIDDAC)continuous support from MIT Portugal Program。
文摘Recently,a disruptive idea was reported about the discovery of a new type of battery named Liquid Displacement Battery(LDB)comprising liquid metal electrodes and molten salt electrolyte.This cell featured a novel concept of a porous electronically conductive faradaic membrane instead of the traditional ion-selective ceramic membrane.LDBs are attractive for stationary storage applications but need mitigation against self-discharge.In the instant battery chemistry,Li|LiCl-PbCl_(2)|Pb,reducing the diffusion coefficient of lead ions can be a way forward and a solution can be the addition of Pb O to the electrolyte.The latter acts as a supplementary barrier and complements the function of the faradaic membrane.The remedial actions improved the cell’s coulombic efficiency from 92%to 97%without affecting the voltage efficiency.In addition,the limiting current density of a 500 m Ah cell increased from 575 to 831 m A cm;and the limiting power from 2.53 to 3.66 W.Finally,the effect of Pb O on the impedance and polarization of the cell was also studied.
文摘A method for topological optimization of structures with discrete variables subjected to dynamic stress and displacement constraints is presented. By using the quasi_static method, the structure optimization problem under dynamic stress and displacement constraints is converted into one subjected to static stress and displacement constraints. The comprehensive algorithm for topological optimization of structures with discrete variables is used to find the optimum solution.
文摘The degenerative disease of the intervertebral disc is nowadays an important health problem,which has still not been understood and solved adequately.The vertebral endplate is regarded as one of the vital elements in the structure of the intervertebral disc.Its constituent cells,the chondrocytes in the endplate,may also be involved in the process of the intervertebral disc degeneration and their role is central both under physiological and pathological conditions.They main functions include a role in homeostasis of the extracellular environment of the intervertebral disc,metabolic support and nutrition of the discal nucleus and annulus beneath and the preservation of the extracellular matrix.Therefore,it is understandable that the cells in the endplate have been in the centre of research from several viewpoints,such as development,degeneration and growth,reparation and remodelling,as well as treatment strategies.In this article,we briefly review the importance of vertebral endplate,which are often overlooked,in the intervertebral disc degeneration.
