Slipped capital femoral epiphysis(SCFE)is a hip disorder that predominantly affects adolescents.The primary pathological change involves the displacement of the femoral head epiphysis from its normal position at the g...Slipped capital femoral epiphysis(SCFE)is a hip disorder that predominantly affects adolescents.The primary pathological change involves the displacement of the femoral head epiphysis from its normal position at the growth plate toward the metaphysis of the femoral neck.This condition can result in hip pain,abnormal gait,and even avascular necrosis of the femoral head,significantly impacting the quality of life in adolescents.Currently,the exact etiology of SCFE remains unclear;however,evidence suggests that risk factors include endocrine disorders,metabolic conditions,and genetic diseases.Endocrine disorders encompass hypothyroidism,growth hormone abnormalities,hypogonadism,and obesity-related hormonal imbalances.Metabolic conditions involve obesity,vitamin D deficiency or rickets,and renal osteodystrophy.Genetic diseases include mutations in the COL2A1 gene,aromatase deficiency,and Prader-Willi syndrome.This review summarizes various medical conditions associated with SCFE and elucidates potential molecular mechanisms from abnormal chondrocyte function in the growth plate,hormonal imbalances and inflammatory/metabolic factors in SCFE based on relevant literature,aim to provide evidence for the prevention and treatment of SCFE.展开更多
The traditional treatment of the hip with a slip of the capital femoral epiphysis has been an in situ fixation using a single screw.This has the sanctity of a long term result.Recent literature stresses the outcomes o...The traditional treatment of the hip with a slip of the capital femoral epiphysis has been an in situ fixation using a single screw.This has the sanctity of a long term result.Recent literature stresses the outcomes of failure to restore the upper femoral alignment and on the basis of the poor results makes a plea for capital realignment.This being a recent development,it lacks the support of long term follow up and it remains to be seen if this is a better alternative of managing displaced and unstable slipped capital femoral epiphysis.The authors look at some of the available literature on the subject to highlight these controversies and their implications for orthopedic surgeons.Other controversies pertain to contralateral fixation,duration of immobilization and amount of weight bearing after an in situ fixation.展开更多
AIM: To analyze the surgical results of a slipped medial rectus muscle(MRM) after hang back recession surgery for esotropia.METHODS: Twenty-one patients who underwent reexploration for diagnosed slipped muscle after h...AIM: To analyze the surgical results of a slipped medial rectus muscle(MRM) after hang back recession surgery for esotropia.METHODS: Twenty-one patients who underwent reexploration for diagnosed slipped muscle after hang back recession surgery were included in this retrospective study. Dynamic magnetic resonance imaging was performed to identify the location of the slipped muscle.Ocular motility was evaluated with assessment with prism and cover test in gaze at cardinal positions. The operations were performed by the same consultant.Intraoperative forced duction test was performed under general anesthesia. The empty sheath of the slipped MRM was resected and the muscle was advanced to the original insertion site in all patients.RESULTS: The average age of 21 patients who had consecutive exotropia with a slipped MRM at the time of presentation was 17.4±5.4y(5-50y). The average duration between the first operation and the diagnosis of the slipped muscle was 25mo(12 to 36mo). The mean follow up after the corrective surgery was 28 mo. The mean preoperative adduction limitation in the field of action of the slipped muscle was-2.26(ranging from-1 to-4). All patients had full adduction postoperatively.CONCLUSION: The diagnosis of the slipped muscle should be confirmed during the strabismus surgery. The slipped muscle may be caused due to insufficient suture and excessive rubbing of the eye. When divergent strabismus is observed after the recession of the MRM, a slipped muscle should be considered in the differential diagnosis.展开更多
BACKGROUND Slipped capital femoral epiphysis(SCFE)occurs in adolescents and has an incidence of around 10 per 100000 children.Children presenting with a unilateral SCFE are 2335 times more likely to develop a contrala...BACKGROUND Slipped capital femoral epiphysis(SCFE)occurs in adolescents and has an incidence of around 10 per 100000 children.Children presenting with a unilateral SCFE are 2335 times more likely to develop a contralateral SCFE than the general population.Prognostic factors that have been suggested to increase the risk of contralateral slip include a younger patient,an underlying endocrine disorder,growth hormone use and a higher radiographic posterior sloping angle.However,there is still much debate on the advantages and disadvantages of prophylactic fixation of the unaffected side in an otherwise healthy patient.AIM To investigate the risk rate of contralateral SCFE and assess the(dis)advantages of prophylactic fixation of the contralateral hip.METHODS A systematic literature search was performed in the Embase,Medline,Web of Science Core Collection and Cochrane databases.Search terms included‘slipped capital femoral epiphysis,’‘fixation,’‘contralateral,’and derivatives.The eligibility of the acquired articles was independently assessed by the authors and additional relevant articles were included through cross-referencing.Publications were considered eligible for inclusion if they presented data about otherwise healthy children with primarily unilateral SCFE and the outcomes of prophylactically pinning their unaffected side,or about the rates of contralateral slips and complications thereof.The study quality of the included articles was assessed independently by the authors by means of the methodological index for non-randomized studies criteria.RESULTS Of 293 identified unique publications,we included 26 studies with a total of 12897 patients.1762 patients(14%)developed a subsequent symptomatic contralateral slip.In addition,38%of patients developed a subsequent slip on the contralateral side without experiencing clinical symptoms.The most outspoken advantage of prophylactic fixation of the contralateral hip in the literature is prevention of an(asymptomatic)slip,thus reducing the increased risk of avascular necrosis(AVN),cam morphology and osteoarthritis.Disadvantages include an increased risk of infection,AVN,peri-implant fractures,loss of fixation as well as migration of hardware and morphologic changes as a consequence of growth guidance.These risks,however,appeared to only occur incidentally and were usually mild compared to the risks involved with an actual SCFE.CONCLUSION The advantages of prophylactic pinning of the unaffected side in otherwise healthy patients with unilateral SCFE seem to outweigh the disadvantages.The final decision for treatment remains to be patient-tailored.展开更多
BACKGROUND Currents trends in pediatric orthopaedics has seen an increase in surgeries being successfully completed in an outpatient setting.Two recent examples include slipped capital femoral epiphysis(SCFE)and Bloun...BACKGROUND Currents trends in pediatric orthopaedics has seen an increase in surgeries being successfully completed in an outpatient setting.Two recent examples include slipped capital femoral epiphysis(SCFE)and Blount’s disease.Surgical indications are well-studied for each pathology,but to our knowledge,there is an absence in literature analyzing safety and efficacy of inpatient vs outpatient management of either condition.We believed there would be no increase in adverse outcomes associated with outpatient treatment of either conditions.AIM To investigate whether outpatient surgery for SCFE and Blount’s disease is associated with increased risk of adverse outcomes.METHODS The 2015-2017 American College of Surgeons National Surgical Quality Improvement Program Pediatric Registries were used to compare patient characteristics,rates of complications,and readmissions between outpatient and inpatient surgery for SCFE and Blount’s disease.RESULTS Total 1788 SCFE database entries were included,30%were performed in an outpatient setting.In situ pinning was used in 98.5%of outpatient surgeries and 87.8%of inpatient surgeries(P<0.0001).Inpatients had a greater percent of total complications than outpatients 2.57%and 1.65%respectively.Regarding Blount’s disease,outpatient surgeries constituted 41.2%of the 189 procedures included in our study.The majority of inpatients were treated with a tibial osteotomy,while the majority of outpatients had a physeal arrest(P<0.0001).Complications were encountered in 7.4%of patients,with superficial surgical site infections and wound dehiscence being the most common.1.6%of patients had a readmission.No differences in complication and readmission risks were found between inpatients and outpatients.CONCLUSION The current trend is shifting towards earlier discharges and performing procedures in an outpatient setting.This can be safely performed for a large portion of children with SCFE and Blount’s disease without increasing the risk of complications or readmissions.Osteotomies are more commonly performed in an inpatient setting where monitoring is available.展开更多
Introduction: Slipped capital femoral epiphysis (SCFE) is a common hip disorder in adolescents. The most serious complication is avascular necrosis (AVN), which has lasting sequelae. The objective of this study was to...Introduction: Slipped capital femoral epiphysis (SCFE) is a common hip disorder in adolescents. The most serious complication is avascular necrosis (AVN), which has lasting sequelae. The objective of this study was to determine the rate of AVN in stable slips. Method: We reviewed retrospectively all the children treated for SCFE between 2004 and 2008 at Princess Margaret Hospital. Results: Of a total of 67 patients, 51 (76%) were stable slips and 16 (24%) unstable. Avascular necrosis developed in 3 patients with stable slip (5.9%) and in 6 with unstable slip (37.5%). There was no statistically significant association found between AVN and age, weight, slip severity, pin position, number of pins used, experience of the surgeon or side affected. Those with stable presentations can develop AVN2, males are more likely and the possibility of developing AVN increases as the time from presentation to operation increased. Conclusion: AVN can occur in stable slips without joint penetration. This combined with male sex and increased time to operation, increases the risk of AVN.展开更多
Pseudomyogenic hemangioendothelioma is a rare, recently described neoplasm that usually presents as multifocal lesions in a single extremity. The disease has demonstrated a high propensity for infiltrative growth and ...Pseudomyogenic hemangioendothelioma is a rare, recently described neoplasm that usually presents as multifocal lesions in a single extremity. The disease has demonstrated a high propensity for infiltrative growth and local recurrence but limited metastatic potential. Variations of histological appearance and immunohistochemical signatures have been described, but typically involve spindle or polygonal cells with nuclear atypia and neutrophilic infiltration. Here we present a case report of an 8-year-old female who presented with hip pain that was initially diagnosed and managed as a slipped capital femoral epiphysis (SCFE). Subsequent evaluation led to the diagnosis of pseudomyogenic hemangioendothelioma of bone. Due to the degree of osseous destruction, described patterns of local recurrence, and metastatic potential of this neoplasm, a wide resection with endoprosthetic reconstruction of the proximal femur was performed. This case highlights the importance of due diligence in the diagnoses of SCFE and bone tumors in young patients with abnormalities of the proximal femur, including consideration of the need for biopsy.展开更多
Rock fractures or faults could be reactivated by the thermal stress generated during the decay process of the high-level radioactive waste in deep geological repositories(DGRs).Understanding thermoshearing behavior an...Rock fractures or faults could be reactivated by the thermal stress generated during the decay process of the high-level radioactive waste in deep geological repositories(DGRs).Understanding thermoshearing behavior and its influencing factors are important for the long-term performance assessment of DGRs.We designed multistage mechanical(M)shear tests and thermomechanical(TM)shear tests on three 100 mm-cubic granite specimens,each containing a single inclined sawcut fracture with distinct microroughness of 8-15μm.M test results have shown that the static friction coefficient of the granite fracture decreases in proportion to the increase in the logarithm of the loading rate within the range of 1-15 kPa/s.For the given heating and boundary conditions,thermal loading rate,i.e.,thermal stress increment with heating time,is measured to be around 1 kPa/s in the fractured granite.Thermoshearing can be well predicted by the linear Mohr-Coulomb failure envelope deduced from M shear tests employing a loading rate that is comparable with the thermal loading rate.The granite fractures exhibited two distinct slip patterns during the mechanical shearing,i.e.,stick-slip observed in the smooth fracture and stable sliding in the relatively rough surface.In contrast,the mechanical loading rate(1-15 kPa/s)investigated in this study appears to not influence the slip pattern.Unlike those in M shear tests,thermoshearing in both smooth and relatively rough fractures show stable sliding with a very slow peak velocity of around 0.002μm/s.展开更多
The trade-offbetween strength and ductility remains a persistent obstacle in the development of advanced structural materials.In the present study,a novel dual-heterogeneous structure with a bimodal grain distribution...The trade-offbetween strength and ductility remains a persistent obstacle in the development of advanced structural materials.In the present study,a novel dual-heterogeneous structure with a bimodal grain distribution in both ferrite and austenite phases was fabricated via cold rolling and partial recrystallization annealing on solution-treated 2205 duplex stainless steel(DSS).The processed steel exhibited superior mechanical properties,with the yield strength increasing from 586 MPa to 903 MPa,and the ultimate tensile strength from 796 MPa to 1082 MPa,while maintaining a high total elongation of 35.3%.Based on in-situ electron backscatter diffraction(EBSD)and scanning electron microscope(SEM)analyses,the microstructural deformation behavior and strengthening mechanisms of the dual-heterostructured 2205 DSS were elucidated.The outstanding combination of strength and ductility was ascribed to the synergistic effects of grain refinement,dislocation strengthening,and hetero-deformation induced(HDI)strengthening.Moreover,the high ductility in DSS was attributed to the coactivation of cross-slip systems in ferrite{110}and{112}along with the single-slip systems in austenite{111}.These findings provide a new strategy for the design and development of high-strength and ultra-high-strength DSSs.展开更多
A complex geological environment with faults can be encountered in the process of coal mining.Fault activation can cause instantaneous structure slipping,releasing a significant amount of elastic strain energy during ...A complex geological environment with faults can be encountered in the process of coal mining.Fault activation can cause instantaneous structure slipping,releasing a significant amount of elastic strain energy during underground coal mining.This would trigger strong rockburst disasters.To understand the occurrence of fault-slip induced rockbursts,we developed a physical model test system for fault-slip induced rockbursts in coal mine drifts.The boundary energy storage(BES)loading apparatus and bottom rapid retraction(BRR)apparatus are designed to realize energy compensation and continuous boundary stress transfer of the surrounding rocks for instantaneous fault slip,as well as to provide space for the potential fault slip.Taking the typical fault-slip induced rockburst in the Xinjulong Coal Mine,China,as the background,we conducted a model test using the test system.The deformation and stress in the rock surrounding the drift and the support unit force during fault slip are analyzed.The deformation and failure characteristics and dynamic responses of drifts under fault-slip induced rockbursts are obtained.The test results illustrate the rationality and effectiveness of the test system.Finally,corresponding recommendations and prospects are proposed based on our findings.展开更多
As coal mining depth increases,the combined effects of high stress,mining stress,and fault structures make dynamic impact hazards more frequent.The reproduction of dynamic impact phenomena is basis for studying their ...As coal mining depth increases,the combined effects of high stress,mining stress,and fault structures make dynamic impact hazards more frequent.The reproduction of dynamic impact phenomena is basis for studying their occurrence patterns and control mechanisms.Physical simulation test represents an efficacious methodology.However,there is currently a lack of simulation devices that can effectively simulate two types of dynamic impact phenomena,including high stress and fault slip dynamic impact.To solve aforementioned issues,the physical simulation test system for dynamic impact in deep roadways developed by authors is employed to carry out comparative tests of high stress and fault slip dynamic impact.The phenomena of high stress and fault slip dynamic impact are reproduced successfully.A comparative analysis is conducted on dynamic phenomena,stress evolution,roadway deformation,and support force.The high stress dynamic impact roadway instability mode,which is characterized by the release of high energy accompanied by symmetric damage,and the fault slip dynamic impact roadway instability mode,which is characterized by the propagation of unilateral stress waves accompanied by asymmetric damage,are clarified.On the basis,the differentiated control concepts for different types of dynamic impact in deep roadways are proposed.展开更多
Purpose–This study aims to propose a cooperative adhesion control method for trains with multiple motors electric locomotives.The method is intended to optimize the output torque of each motor,maximize the utilizatio...Purpose–This study aims to propose a cooperative adhesion control method for trains with multiple motors electric locomotives.The method is intended to optimize the output torque of each motor,maximize the utilization of train adhesion within the total torque command,reduce the train skidding/sliding phenomenon and achieve optimal adhesion utilization for each axle,thus realizing the optimal allocation of the multi-motor electric locomotives.Design/methodology/approach–In this study,a model predictive control(MPC)-based cooperative maximum adhesion tracking control method for multi-motor electric locomotives is presented.Firstly,train traction system with multiple motors is constructed in accordance with Newton’s second law.These equations include the train dynamics equations,the axle dynamics equations,and the wheel-rail adhesion coefficient equations.Then,a new MPC-based multi-axle adhesion co-optimization method is put forward.This method calculates the optimal output torque through real-time iteration based on the known reference slip speed to achieve multi-axle co-optimization under different circumstances.Findings–This paper presents a MPC system designed for the cooperative control of multi-axle adhesion.The results indicate that the proposed control system is able to optimize the adhesion of multiple axles under numerous different conditions and achieve the optimal power distribution based on the reduction of train skidding/sliding.Originality/value–This study presents a novel cooperative adhesion tracking control scheme.It is designed for multi-motor electric locomotives,which has rarely been studied before.And simulations are carried out in different conditions,including variable surfaces and motor failing.展开更多
The deformation and fracture of a third-generation single crystal superalloy during in-situ tension at room temperature were investigated at multiple scales by scanning electron microscope,electron back-scattered diff...The deformation and fracture of a third-generation single crystal superalloy during in-situ tension at room temperature were investigated at multiple scales by scanning electron microscope,electron back-scattered diffractometer,and transmission electron microscope to reveal the deformation and fracture mechanism during tension.The proportion of low angle boundaries(LABs)with angles from 2.5°to 5.5°increases during tension.The change in LABs is particularly pronounced after elongation over 7%.The initiation of microcracks is caused by{111}<110>slip systems.After initiation,the crack size along the stress direction increases whereas the size extension along slip systems is suppressed.The fracture mode of the alloy is quasi-cleavage fracture and the slip lines near the fracture are implicit at room temperature.展开更多
The high-cycle fatigue fracture characteristics and damage mechanism of nickel-based single crystal superalloys at 850℃ was investigated.The results indicate that high-cycle fatigue cracks in single crystal superallo...The high-cycle fatigue fracture characteristics and damage mechanism of nickel-based single crystal superalloys at 850℃ was investigated.The results indicate that high-cycle fatigue cracks in single crystal superalloys generally originate from defect locations on the subsurface or interior of the specimen at 850℃.Under the condition of stress ratio R=0.05,as the fatigue load decreases,the high-cycle fatigue life gradually increases.The high-cycle fatigue fracture is mainly characterized by octahedral slip mechanism.At high stress and low lifespan,the fracture exhibits single or multiple slip surface features.Some fractures originate along a vertical small plane and then propagate along the{111}slip surface.At low stress and high lifespan,the fracture surface tend to alternate and expand along multiple slip planes after originating from subsurface or internal sources,exhibiting characteristics of multiple slip planes.Through electron backscatter diffraction and transmission electron microscope analysis,there is obvious oxidation behavior on the surface of the high-cycle fatigue fracture,and the fracture section is composed of oxidation layer,distortion layer,and matrix layer from the outside to the inside.Among them,the main components of the oxidation layer are oxides of Ni and Co.The distortion layer is mainly distributed in the form of elongated or short rod-shaped oxides of Al,Ta,and W.The matrix layer is a single crystal layer.Crack initiation and propagation mechanism were obtained by systematical analysis of a large number of highcycle fatigue fractures.In addition,the stress ratio of 0.05 is closer to the vibration mode of turbine blades during actual service,providing effective guidance for the study of failure and fracture mechanisms of turbine blades.展开更多
The present work reports characteristics of dislocation slip behavior in an equi-atomic HfNbTiZr refractory medium entropy alloy(RMEA)and its systematic comparison with pure niobium(Nb).Fully-recrystallized specimens ...The present work reports characteristics of dislocation slip behavior in an equi-atomic HfNbTiZr refractory medium entropy alloy(RMEA)and its systematic comparison with pure niobium(Nb).Fully-recrystallized specimens were fabricated by cold rolling and subsequent annealing,and uniaxial tensile deformation was applied at room temperature.Slip trace morphologies on the surfaces of the tensile-deformed ma-terials were quantitatively characterized,and the so-calledψand x relationships of the observed slip traces were evaluated by a newly developed method for polycrystalline specimens.Wavy slip traces were observed in most grains in the pure Nb.They consisted of low-indexed slip planes,such as{110},and{112},and high-indexed(or undetermined)slip planes.Some straight slip traces persisting on the low-indexed slip planes were also found in the pure Nb.In contrast,straight slip traces were dominant in the RMEA.The straight slip traces in the RMEA were not parallel to particular slip planes but mostly distributed along the maximum shear stress plane(MSSP),indicating that frequent cross slip in very short intervals occurred.Large deviations of slip planes from the MSSP in a few grains of the RMEA were attributed to the slip transfer from neighboring grains as a characteristic of polycrystalline materi-als.Frequent cross slip in short intervals,attributed to homogeneous slip resistance distribution for screw dislocations in the RMEA originating from the chemical heterogeneity on an atomic scale,was proposed as a novel mechanism responsible for the unique slip behavior and macroscopic deformation behavior.展开更多
The grain-scale tension-compression(T-C)asymmetric slip behavior and geometrically necessary dislocation(GND)density in an aged and twin-free Mg-10Y sheet were statistically studied using slip trace analysis and elect...The grain-scale tension-compression(T-C)asymmetric slip behavior and geometrically necessary dislocation(GND)density in an aged and twin-free Mg-10Y sheet were statistically studied using slip trace analysis and electron backscatter diffraction(EBSD)analysis.A significantly asymmetric slip activity,i.e.,higher tensile slip activity and proportion of non-basal slip,was manifested.Prismatic〈a〉(37.1%)and basal〈a〉(27.6%)slips dominated the tensile deformation,followed by pyramidalⅡ〈c+a〉slip(20.0%).While during compression,basal〈a〉slip(61.9%)was the most active slip mode,and only 6.9% pyramidalⅡ〈c+a〉slip was observed.The critical resolved shear stress(CRSS)ratio was estimated based on~800 sets of the identified slip traces,which suggested that the CRSS_(pyrⅡ)/CRSS_(bas)for compression was~3 times than that of tension.The pyramidalⅡ〈c+a〉slip was more active when the slip plane was under tension than under compression,which was consistent with the calculated asymmetric CRSS_(pyrⅡ)/CRSS_(bas).The activity of multiple slip,cross slip and slip transfer,as well as the GND density were also T-C asymmetric.This work thoughtfully demonstrated the T-C asymmetric slip behavior and plastic heterogeneity in Mg alloys which was believed to be responsible for the macroscopic T-C asymmetry when twinning was absent.The present statistical results are valuable for validating and/or facilitating crystal plasticity simulations.展开更多
Quantitative studies on the interseismic and coseismic deformation characteristics and analysis of the interplay between the seismogenic fault and neighboring faults are crucial for understanding the kinematic feature...Quantitative studies on the interseismic and coseismic deformation characteristics and analysis of the interplay between the seismogenic fault and neighboring faults are crucial for understanding the kinematic features and assessing potential seismic hazards. In this study, the interseismic and coseismic deformation of the 2023 Jishishan M_(S)6.2 earthquake(JSSEQ), including the strain rate field, the slip rates,and locking depths of the seismogenic fault during the interseismic period, were obtained. Moreover, the coseismic slip distribution and geometric attributes of the seismogenic fault were further examined.Finally, the potential earthquake hazard in the vicinity was identified by analyzing the Coulomb failure stress changes(ΔCFS). Before the JSSEQ, the maximum shear and dilatational strain rates near the epicenter were significantly lower, and the seismogenic fault was strongly coupled with thrust and dextral strike-slip motion. The maximum displacement of GNSS stations is about 25 mm, about 11 km southwest of the epicenter. The ascending and descending observations reveal a significantly thrustdominated movement, with maximum line of sight displacements of 78 and 83 mm, respectively.Comparing two coseismic slip distribution results and previous studies, it is considered that the east dipping seismogenic fault is more reasonable. The coseismic fault slip took place at a depth of 7.1-13.2 km, with a maximum slip of 0.43 m and a moment magnitude of 6.1. The earthquake resulted in noticeable stress loading on the southeastern end of the Lajishan north margin fault zone and the Lajishan south margin fault zone, as well as the western end of the West Qinling fault zone, which should be given more attention in future.展开更多
This work investigated the effects of grain size(GS)on individual slip mode activities and the corresponding Hall-Petch coefficients in a rolled basal-textured pure Mg sheet under uniaxial tension using statistical sl...This work investigated the effects of grain size(GS)on individual slip mode activities and the corresponding Hall-Petch coefficients in a rolled basal-textured pure Mg sheet under uniaxial tension using statistical slip trace analysis and electron backscatter diffraction.The studied regions covered a total of 1150 grains,in which 136 sets of slip traces were identified and analyzed in detail.The basalslip always dominated the deformation,whose frequencies decreased(from 81.0%to 62.5%)with increasing GS(from 10 to 85μm).The prismaticslip activity increased from 10.8%(10μm)to 27.5%(85μm),while that for pyramidal II<c+a>slip was almost constant.Critical resolved shear stress(CRSS)ratios were estimated based on the identified slip activity statistics,and then the Hall-Petch coefficients(k)of individual slip modes were calculated.The k value for prismaticslip(194 MPa·μm^(1/2))was lower than that for pyramidal II<c+a>slip(309 MPa·μm^(1/2)),which implies that pyramidal II<c+a>slip was more GS sensitive.Twinning activity exhibited a positive correlation with GS,though it remained limited partly due to the unfavorable loading direction.The macroscopic Hall-Petch relationship was divided into two regions,i.e.,the k value(753 MPa·μm^(1/2))for the coarse-grain region(30-85μm)was significantly larger than that(118 MPa·μm^(1/2))of the fine-grain region(10-30μm),which could be attributed to the transition of predominant deformation mechanisms from slip to slip combined twinning with increasing GS.This work provides detailed and quantitative experimental data of the GS effects on individual slip activities of Mg and provides new insights into the Hall-Petch relationship for individual slip modes.展开更多
基金Supported by the Science Project of Hunan Provincial Healthy Commission,No.20230844.
文摘Slipped capital femoral epiphysis(SCFE)is a hip disorder that predominantly affects adolescents.The primary pathological change involves the displacement of the femoral head epiphysis from its normal position at the growth plate toward the metaphysis of the femoral neck.This condition can result in hip pain,abnormal gait,and even avascular necrosis of the femoral head,significantly impacting the quality of life in adolescents.Currently,the exact etiology of SCFE remains unclear;however,evidence suggests that risk factors include endocrine disorders,metabolic conditions,and genetic diseases.Endocrine disorders encompass hypothyroidism,growth hormone abnormalities,hypogonadism,and obesity-related hormonal imbalances.Metabolic conditions involve obesity,vitamin D deficiency or rickets,and renal osteodystrophy.Genetic diseases include mutations in the COL2A1 gene,aromatase deficiency,and Prader-Willi syndrome.This review summarizes various medical conditions associated with SCFE and elucidates potential molecular mechanisms from abnormal chondrocyte function in the growth plate,hormonal imbalances and inflammatory/metabolic factors in SCFE based on relevant literature,aim to provide evidence for the prevention and treatment of SCFE.
文摘The traditional treatment of the hip with a slip of the capital femoral epiphysis has been an in situ fixation using a single screw.This has the sanctity of a long term result.Recent literature stresses the outcomes of failure to restore the upper femoral alignment and on the basis of the poor results makes a plea for capital realignment.This being a recent development,it lacks the support of long term follow up and it remains to be seen if this is a better alternative of managing displaced and unstable slipped capital femoral epiphysis.The authors look at some of the available literature on the subject to highlight these controversies and their implications for orthopedic surgeons.Other controversies pertain to contralateral fixation,duration of immobilization and amount of weight bearing after an in situ fixation.
文摘AIM: To analyze the surgical results of a slipped medial rectus muscle(MRM) after hang back recession surgery for esotropia.METHODS: Twenty-one patients who underwent reexploration for diagnosed slipped muscle after hang back recession surgery were included in this retrospective study. Dynamic magnetic resonance imaging was performed to identify the location of the slipped muscle.Ocular motility was evaluated with assessment with prism and cover test in gaze at cardinal positions. The operations were performed by the same consultant.Intraoperative forced duction test was performed under general anesthesia. The empty sheath of the slipped MRM was resected and the muscle was advanced to the original insertion site in all patients.RESULTS: The average age of 21 patients who had consecutive exotropia with a slipped MRM at the time of presentation was 17.4±5.4y(5-50y). The average duration between the first operation and the diagnosis of the slipped muscle was 25mo(12 to 36mo). The mean follow up after the corrective surgery was 28 mo. The mean preoperative adduction limitation in the field of action of the slipped muscle was-2.26(ranging from-1 to-4). All patients had full adduction postoperatively.CONCLUSION: The diagnosis of the slipped muscle should be confirmed during the strabismus surgery. The slipped muscle may be caused due to insufficient suture and excessive rubbing of the eye. When divergent strabismus is observed after the recession of the MRM, a slipped muscle should be considered in the differential diagnosis.
文摘BACKGROUND Slipped capital femoral epiphysis(SCFE)occurs in adolescents and has an incidence of around 10 per 100000 children.Children presenting with a unilateral SCFE are 2335 times more likely to develop a contralateral SCFE than the general population.Prognostic factors that have been suggested to increase the risk of contralateral slip include a younger patient,an underlying endocrine disorder,growth hormone use and a higher radiographic posterior sloping angle.However,there is still much debate on the advantages and disadvantages of prophylactic fixation of the unaffected side in an otherwise healthy patient.AIM To investigate the risk rate of contralateral SCFE and assess the(dis)advantages of prophylactic fixation of the contralateral hip.METHODS A systematic literature search was performed in the Embase,Medline,Web of Science Core Collection and Cochrane databases.Search terms included‘slipped capital femoral epiphysis,’‘fixation,’‘contralateral,’and derivatives.The eligibility of the acquired articles was independently assessed by the authors and additional relevant articles were included through cross-referencing.Publications were considered eligible for inclusion if they presented data about otherwise healthy children with primarily unilateral SCFE and the outcomes of prophylactically pinning their unaffected side,or about the rates of contralateral slips and complications thereof.The study quality of the included articles was assessed independently by the authors by means of the methodological index for non-randomized studies criteria.RESULTS Of 293 identified unique publications,we included 26 studies with a total of 12897 patients.1762 patients(14%)developed a subsequent symptomatic contralateral slip.In addition,38%of patients developed a subsequent slip on the contralateral side without experiencing clinical symptoms.The most outspoken advantage of prophylactic fixation of the contralateral hip in the literature is prevention of an(asymptomatic)slip,thus reducing the increased risk of avascular necrosis(AVN),cam morphology and osteoarthritis.Disadvantages include an increased risk of infection,AVN,peri-implant fractures,loss of fixation as well as migration of hardware and morphologic changes as a consequence of growth guidance.These risks,however,appeared to only occur incidentally and were usually mild compared to the risks involved with an actual SCFE.CONCLUSION The advantages of prophylactic pinning of the unaffected side in otherwise healthy patients with unilateral SCFE seem to outweigh the disadvantages.The final decision for treatment remains to be patient-tailored.
文摘BACKGROUND Currents trends in pediatric orthopaedics has seen an increase in surgeries being successfully completed in an outpatient setting.Two recent examples include slipped capital femoral epiphysis(SCFE)and Blount’s disease.Surgical indications are well-studied for each pathology,but to our knowledge,there is an absence in literature analyzing safety and efficacy of inpatient vs outpatient management of either condition.We believed there would be no increase in adverse outcomes associated with outpatient treatment of either conditions.AIM To investigate whether outpatient surgery for SCFE and Blount’s disease is associated with increased risk of adverse outcomes.METHODS The 2015-2017 American College of Surgeons National Surgical Quality Improvement Program Pediatric Registries were used to compare patient characteristics,rates of complications,and readmissions between outpatient and inpatient surgery for SCFE and Blount’s disease.RESULTS Total 1788 SCFE database entries were included,30%were performed in an outpatient setting.In situ pinning was used in 98.5%of outpatient surgeries and 87.8%of inpatient surgeries(P<0.0001).Inpatients had a greater percent of total complications than outpatients 2.57%and 1.65%respectively.Regarding Blount’s disease,outpatient surgeries constituted 41.2%of the 189 procedures included in our study.The majority of inpatients were treated with a tibial osteotomy,while the majority of outpatients had a physeal arrest(P<0.0001).Complications were encountered in 7.4%of patients,with superficial surgical site infections and wound dehiscence being the most common.1.6%of patients had a readmission.No differences in complication and readmission risks were found between inpatients and outpatients.CONCLUSION The current trend is shifting towards earlier discharges and performing procedures in an outpatient setting.This can be safely performed for a large portion of children with SCFE and Blount’s disease without increasing the risk of complications or readmissions.Osteotomies are more commonly performed in an inpatient setting where monitoring is available.
文摘Introduction: Slipped capital femoral epiphysis (SCFE) is a common hip disorder in adolescents. The most serious complication is avascular necrosis (AVN), which has lasting sequelae. The objective of this study was to determine the rate of AVN in stable slips. Method: We reviewed retrospectively all the children treated for SCFE between 2004 and 2008 at Princess Margaret Hospital. Results: Of a total of 67 patients, 51 (76%) were stable slips and 16 (24%) unstable. Avascular necrosis developed in 3 patients with stable slip (5.9%) and in 6 with unstable slip (37.5%). There was no statistically significant association found between AVN and age, weight, slip severity, pin position, number of pins used, experience of the surgeon or side affected. Those with stable presentations can develop AVN2, males are more likely and the possibility of developing AVN increases as the time from presentation to operation increased. Conclusion: AVN can occur in stable slips without joint penetration. This combined with male sex and increased time to operation, increases the risk of AVN.
文摘Pseudomyogenic hemangioendothelioma is a rare, recently described neoplasm that usually presents as multifocal lesions in a single extremity. The disease has demonstrated a high propensity for infiltrative growth and local recurrence but limited metastatic potential. Variations of histological appearance and immunohistochemical signatures have been described, but typically involve spindle or polygonal cells with nuclear atypia and neutrophilic infiltration. Here we present a case report of an 8-year-old female who presented with hip pain that was initially diagnosed and managed as a slipped capital femoral epiphysis (SCFE). Subsequent evaluation led to the diagnosis of pseudomyogenic hemangioendothelioma of bone. Due to the degree of osseous destruction, described patterns of local recurrence, and metastatic potential of this neoplasm, a wide resection with endoprosthetic reconstruction of the proximal femur was performed. This case highlights the importance of due diligence in the diagnoses of SCFE and bone tumors in young patients with abnormalities of the proximal femur, including consideration of the need for biopsy.
基金supported by the International Collaborative Research Program(fundamental research,2021-2023)funded by Korea Institute of Civil Engineering and Building Technology(KICT).
文摘Rock fractures or faults could be reactivated by the thermal stress generated during the decay process of the high-level radioactive waste in deep geological repositories(DGRs).Understanding thermoshearing behavior and its influencing factors are important for the long-term performance assessment of DGRs.We designed multistage mechanical(M)shear tests and thermomechanical(TM)shear tests on three 100 mm-cubic granite specimens,each containing a single inclined sawcut fracture with distinct microroughness of 8-15μm.M test results have shown that the static friction coefficient of the granite fracture decreases in proportion to the increase in the logarithm of the loading rate within the range of 1-15 kPa/s.For the given heating and boundary conditions,thermal loading rate,i.e.,thermal stress increment with heating time,is measured to be around 1 kPa/s in the fractured granite.Thermoshearing can be well predicted by the linear Mohr-Coulomb failure envelope deduced from M shear tests employing a loading rate that is comparable with the thermal loading rate.The granite fractures exhibited two distinct slip patterns during the mechanical shearing,i.e.,stick-slip observed in the smooth fracture and stable sliding in the relatively rough surface.In contrast,the mechanical loading rate(1-15 kPa/s)investigated in this study appears to not influence the slip pattern.Unlike those in M shear tests,thermoshearing in both smooth and relatively rough fractures show stable sliding with a very slow peak velocity of around 0.002μm/s.
基金supported by the National Natural Science Foundation of China(Nos.U1960115 and U21A20116)the Fundamental Research Funds for the Central Universities(No.N232405-10)Special thanks are due to the instrumental and data analysis from Analytical and Testing Center,Northeastern University.
文摘The trade-offbetween strength and ductility remains a persistent obstacle in the development of advanced structural materials.In the present study,a novel dual-heterogeneous structure with a bimodal grain distribution in both ferrite and austenite phases was fabricated via cold rolling and partial recrystallization annealing on solution-treated 2205 duplex stainless steel(DSS).The processed steel exhibited superior mechanical properties,with the yield strength increasing from 586 MPa to 903 MPa,and the ultimate tensile strength from 796 MPa to 1082 MPa,while maintaining a high total elongation of 35.3%.Based on in-situ electron backscatter diffraction(EBSD)and scanning electron microscope(SEM)analyses,the microstructural deformation behavior and strengthening mechanisms of the dual-heterostructured 2205 DSS were elucidated.The outstanding combination of strength and ductility was ascribed to the synergistic effects of grain refinement,dislocation strengthening,and hetero-deformation induced(HDI)strengthening.Moreover,the high ductility in DSS was attributed to the coactivation of cross-slip systems in ferrite{110}and{112}along with the single-slip systems in austenite{111}.These findings provide a new strategy for the design and development of high-strength and ultra-high-strength DSSs.
基金support from the National Natural Science Foundation of China (Grant Nos.51927807,42077267 and 42277174).
文摘A complex geological environment with faults can be encountered in the process of coal mining.Fault activation can cause instantaneous structure slipping,releasing a significant amount of elastic strain energy during underground coal mining.This would trigger strong rockburst disasters.To understand the occurrence of fault-slip induced rockbursts,we developed a physical model test system for fault-slip induced rockbursts in coal mine drifts.The boundary energy storage(BES)loading apparatus and bottom rapid retraction(BRR)apparatus are designed to realize energy compensation and continuous boundary stress transfer of the surrounding rocks for instantaneous fault slip,as well as to provide space for the potential fault slip.Taking the typical fault-slip induced rockburst in the Xinjulong Coal Mine,China,as the background,we conducted a model test using the test system.The deformation and stress in the rock surrounding the drift and the support unit force during fault slip are analyzed.The deformation and failure characteristics and dynamic responses of drifts under fault-slip induced rockbursts are obtained.The test results illustrate the rationality and effectiveness of the test system.Finally,corresponding recommendations and prospects are proposed based on our findings.
基金supported by the National Natural Science Foundation of China(Nos.U24A2088,42177130,42277174,and 42477166).
文摘As coal mining depth increases,the combined effects of high stress,mining stress,and fault structures make dynamic impact hazards more frequent.The reproduction of dynamic impact phenomena is basis for studying their occurrence patterns and control mechanisms.Physical simulation test represents an efficacious methodology.However,there is currently a lack of simulation devices that can effectively simulate two types of dynamic impact phenomena,including high stress and fault slip dynamic impact.To solve aforementioned issues,the physical simulation test system for dynamic impact in deep roadways developed by authors is employed to carry out comparative tests of high stress and fault slip dynamic impact.The phenomena of high stress and fault slip dynamic impact are reproduced successfully.A comparative analysis is conducted on dynamic phenomena,stress evolution,roadway deformation,and support force.The high stress dynamic impact roadway instability mode,which is characterized by the release of high energy accompanied by symmetric damage,and the fault slip dynamic impact roadway instability mode,which is characterized by the propagation of unilateral stress waves accompanied by asymmetric damage,are clarified.On the basis,the differentiated control concepts for different types of dynamic impact in deep roadways are proposed.
基金supported by Scientific Research Projects of China Association of Metros(CAMET-KY-2022039)State Key Laboratory of Traction and Control System of EMU and Locomotive(2023YJ386).
文摘Purpose–This study aims to propose a cooperative adhesion control method for trains with multiple motors electric locomotives.The method is intended to optimize the output torque of each motor,maximize the utilization of train adhesion within the total torque command,reduce the train skidding/sliding phenomenon and achieve optimal adhesion utilization for each axle,thus realizing the optimal allocation of the multi-motor electric locomotives.Design/methodology/approach–In this study,a model predictive control(MPC)-based cooperative maximum adhesion tracking control method for multi-motor electric locomotives is presented.Firstly,train traction system with multiple motors is constructed in accordance with Newton’s second law.These equations include the train dynamics equations,the axle dynamics equations,and the wheel-rail adhesion coefficient equations.Then,a new MPC-based multi-axle adhesion co-optimization method is put forward.This method calculates the optimal output torque through real-time iteration based on the known reference slip speed to achieve multi-axle co-optimization under different circumstances.Findings–This paper presents a MPC system designed for the cooperative control of multi-axle adhesion.The results indicate that the proposed control system is able to optimize the adhesion of multiple axles under numerous different conditions and achieve the optimal power distribution based on the reduction of train skidding/sliding.Originality/value–This study presents a novel cooperative adhesion tracking control scheme.It is designed for multi-motor electric locomotives,which has rarely been studied before.And simulations are carried out in different conditions,including variable surfaces and motor failing.
文摘The deformation and fracture of a third-generation single crystal superalloy during in-situ tension at room temperature were investigated at multiple scales by scanning electron microscope,electron back-scattered diffractometer,and transmission electron microscope to reveal the deformation and fracture mechanism during tension.The proportion of low angle boundaries(LABs)with angles from 2.5°to 5.5°increases during tension.The change in LABs is particularly pronounced after elongation over 7%.The initiation of microcracks is caused by{111}<110>slip systems.After initiation,the crack size along the stress direction increases whereas the size extension along slip systems is suppressed.The fracture mode of the alloy is quasi-cleavage fracture and the slip lines near the fracture are implicit at room temperature.
基金National Science and Technology Major Project(J2019-VI-0022-0138)。
文摘The high-cycle fatigue fracture characteristics and damage mechanism of nickel-based single crystal superalloys at 850℃ was investigated.The results indicate that high-cycle fatigue cracks in single crystal superalloys generally originate from defect locations on the subsurface or interior of the specimen at 850℃.Under the condition of stress ratio R=0.05,as the fatigue load decreases,the high-cycle fatigue life gradually increases.The high-cycle fatigue fracture is mainly characterized by octahedral slip mechanism.At high stress and low lifespan,the fracture exhibits single or multiple slip surface features.Some fractures originate along a vertical small plane and then propagate along the{111}slip surface.At low stress and high lifespan,the fracture surface tend to alternate and expand along multiple slip planes after originating from subsurface or internal sources,exhibiting characteristics of multiple slip planes.Through electron backscatter diffraction and transmission electron microscope analysis,there is obvious oxidation behavior on the surface of the high-cycle fatigue fracture,and the fracture section is composed of oxidation layer,distortion layer,and matrix layer from the outside to the inside.Among them,the main components of the oxidation layer are oxides of Ni and Co.The distortion layer is mainly distributed in the form of elongated or short rod-shaped oxides of Al,Ta,and W.The matrix layer is a single crystal layer.Crack initiation and propagation mechanism were obtained by systematical analysis of a large number of highcycle fatigue fractures.In addition,the stress ratio of 0.05 is closer to the vibration mode of turbine blades during actual service,providing effective guidance for the study of failure and fracture mechanisms of turbine blades.
基金supported by the Elements Strategy Initiative for Structural Materials(ESISM,No.JPMXP0112101000)the JSP EIG CONCERT-Japan(No.JPMJSC21C6)+5 种基金the Grant-in-Aid for Scientific Research on Innovative Area“High Entropy Alloys”(Nos.JP18H05455 and JP18H05451)the Grant-in-Aid for Scientific Re-search(A)(Nos.JP20H00306 and JP23H00234)the Grant-in-Aid for Research Activity Start-up(No.JP21K20487)the Grant-in-Aid for Early-Career Scientists(No.JP22K14501)the Grant-in-Aid for JSPS Research Fellow(No.JP18J20766)supported by China Scholarship Council(CSC),China.
文摘The present work reports characteristics of dislocation slip behavior in an equi-atomic HfNbTiZr refractory medium entropy alloy(RMEA)and its systematic comparison with pure niobium(Nb).Fully-recrystallized specimens were fabricated by cold rolling and subsequent annealing,and uniaxial tensile deformation was applied at room temperature.Slip trace morphologies on the surfaces of the tensile-deformed ma-terials were quantitatively characterized,and the so-calledψand x relationships of the observed slip traces were evaluated by a newly developed method for polycrystalline specimens.Wavy slip traces were observed in most grains in the pure Nb.They consisted of low-indexed slip planes,such as{110},and{112},and high-indexed(or undetermined)slip planes.Some straight slip traces persisting on the low-indexed slip planes were also found in the pure Nb.In contrast,straight slip traces were dominant in the RMEA.The straight slip traces in the RMEA were not parallel to particular slip planes but mostly distributed along the maximum shear stress plane(MSSP),indicating that frequent cross slip in very short intervals occurred.Large deviations of slip planes from the MSSP in a few grains of the RMEA were attributed to the slip transfer from neighboring grains as a characteristic of polycrystalline materi-als.Frequent cross slip in short intervals,attributed to homogeneous slip resistance distribution for screw dislocations in the RMEA originating from the chemical heterogeneity on an atomic scale,was proposed as a novel mechanism responsible for the unique slip behavior and macroscopic deformation behavior.
基金supported by the National Natural Science Foundation of China(No.52171125)the Sichuan Science and Technology Program(No.2024NSFSC0193)。
文摘The grain-scale tension-compression(T-C)asymmetric slip behavior and geometrically necessary dislocation(GND)density in an aged and twin-free Mg-10Y sheet were statistically studied using slip trace analysis and electron backscatter diffraction(EBSD)analysis.A significantly asymmetric slip activity,i.e.,higher tensile slip activity and proportion of non-basal slip,was manifested.Prismatic〈a〉(37.1%)and basal〈a〉(27.6%)slips dominated the tensile deformation,followed by pyramidalⅡ〈c+a〉slip(20.0%).While during compression,basal〈a〉slip(61.9%)was the most active slip mode,and only 6.9% pyramidalⅡ〈c+a〉slip was observed.The critical resolved shear stress(CRSS)ratio was estimated based on~800 sets of the identified slip traces,which suggested that the CRSS_(pyrⅡ)/CRSS_(bas)for compression was~3 times than that of tension.The pyramidalⅡ〈c+a〉slip was more active when the slip plane was under tension than under compression,which was consistent with the calculated asymmetric CRSS_(pyrⅡ)/CRSS_(bas).The activity of multiple slip,cross slip and slip transfer,as well as the GND density were also T-C asymmetric.This work thoughtfully demonstrated the T-C asymmetric slip behavior and plastic heterogeneity in Mg alloys which was believed to be responsible for the macroscopic T-C asymmetry when twinning was absent.The present statistical results are valuable for validating and/or facilitating crystal plasticity simulations.
基金funded by the National Natural Science Foundation of China (Grant No. 42204008)the National Key Research and Development Program of China (No. 2022YFC3003703)the Scientific Research Project Coordinating Fund of the First Monitoring and Application Center, China Earthquake Administration (No. FMC2022014)
文摘Quantitative studies on the interseismic and coseismic deformation characteristics and analysis of the interplay between the seismogenic fault and neighboring faults are crucial for understanding the kinematic features and assessing potential seismic hazards. In this study, the interseismic and coseismic deformation of the 2023 Jishishan M_(S)6.2 earthquake(JSSEQ), including the strain rate field, the slip rates,and locking depths of the seismogenic fault during the interseismic period, were obtained. Moreover, the coseismic slip distribution and geometric attributes of the seismogenic fault were further examined.Finally, the potential earthquake hazard in the vicinity was identified by analyzing the Coulomb failure stress changes(ΔCFS). Before the JSSEQ, the maximum shear and dilatational strain rates near the epicenter were significantly lower, and the seismogenic fault was strongly coupled with thrust and dextral strike-slip motion. The maximum displacement of GNSS stations is about 25 mm, about 11 km southwest of the epicenter. The ascending and descending observations reveal a significantly thrustdominated movement, with maximum line of sight displacements of 78 and 83 mm, respectively.Comparing two coseismic slip distribution results and previous studies, it is considered that the east dipping seismogenic fault is more reasonable. The coseismic fault slip took place at a depth of 7.1-13.2 km, with a maximum slip of 0.43 m and a moment magnitude of 6.1. The earthquake resulted in noticeable stress loading on the southeastern end of the Lajishan north margin fault zone and the Lajishan south margin fault zone, as well as the western end of the West Qinling fault zone, which should be given more attention in future.
基金supported by the National Natural Science Foundation of China(No.52171125)the Sichuan Science and Technology Program(No.2024NSFSC0193).
文摘This work investigated the effects of grain size(GS)on individual slip mode activities and the corresponding Hall-Petch coefficients in a rolled basal-textured pure Mg sheet under uniaxial tension using statistical slip trace analysis and electron backscatter diffraction.The studied regions covered a total of 1150 grains,in which 136 sets of slip traces were identified and analyzed in detail.The basalslip always dominated the deformation,whose frequencies decreased(from 81.0%to 62.5%)with increasing GS(from 10 to 85μm).The prismaticslip activity increased from 10.8%(10μm)to 27.5%(85μm),while that for pyramidal II<c+a>slip was almost constant.Critical resolved shear stress(CRSS)ratios were estimated based on the identified slip activity statistics,and then the Hall-Petch coefficients(k)of individual slip modes were calculated.The k value for prismaticslip(194 MPa·μm^(1/2))was lower than that for pyramidal II<c+a>slip(309 MPa·μm^(1/2)),which implies that pyramidal II<c+a>slip was more GS sensitive.Twinning activity exhibited a positive correlation with GS,though it remained limited partly due to the unfavorable loading direction.The macroscopic Hall-Petch relationship was divided into two regions,i.e.,the k value(753 MPa·μm^(1/2))for the coarse-grain region(30-85μm)was significantly larger than that(118 MPa·μm^(1/2))of the fine-grain region(10-30μm),which could be attributed to the transition of predominant deformation mechanisms from slip to slip combined twinning with increasing GS.This work provides detailed and quantitative experimental data of the GS effects on individual slip activities of Mg and provides new insights into the Hall-Petch relationship for individual slip modes.
