OBJECTIVE The inhibitory effect of active ingredients of Tripterygium wilfordii Hook.F.(TWHF)(celastrol,triptolide,triptonide,wilforlide A,wilforgine and wilforine)on human carboxylester⁃ase 1(CES1)and CES2 was detect...OBJECTIVE The inhibitory effect of active ingredients of Tripterygium wilfordii Hook.F.(TWHF)(celastrol,triptolide,triptonide,wilforlide A,wilforgine and wilforine)on human carboxylester⁃ase 1(CES1)and CES2 was detected to investigate the herb-drug interactions(HDIs)of TWHF.METHODS Human liver microsomes catalysed hydrolysis of 2-(2-benzoyl-3-methoxyphenyl)benzothi⁃azole(BMBT)and fluorescein diacetate(FD)were used as the probe reaction to phenotype the activity of CES1 and CES2,respectively.The residual activities of CES1 and CES2 were detected by ultrahigh performance liquid chromatography(UPLC)after intervention with celastrol,triptolide,triptonide,wilforlide A,wilforgine and wilforine(100μmol·L^(-1)).Kinetics analysis,involving half inhibitory concentra⁃tion(IC_(50)),inhibition type and kinetic parameter(Ki),and in vitro-in vivo extrapolation(IVIVE),was carried out to predict the HDIs between these compounds and CES-metabolizing drugs.Molecular docking was performed to analyze the ligand-enzyme interaction.RESULTS Out of the six main con⁃stituents of TWHF,only celastrol exhibited strong inhibition towards both CES1 and CES2,with the inhibitory rates of 97.45%(P<0.05)and 95.62%(P<0.05),respectively.The IC_(50)was 9.95 and 4.02 mol·L^(-1),respectively,and the types of inhibition were all non-competitive inhibition.Based on the kinetics analysis,the Ki values were calculated to be 5.10 and 10.55μmol·L^(-1)for the inhibition of celastrol on CES1 and CES2,respectively.IVIVE indicated that celastrol might disturb the metabolic hydrolysis of clinical drugs in vivo by inhibiting CES1.Molecular docking results showed that hydrogen bonds and hydrophobic contacts contributed to the interaction of celastrol and CESs.CONCLUSION The inhibitory effect of celastrol on CES1 and CES2 might cause HDIs with clinical drugs hydrolysed by CESs.展开更多
The physical properties and chemical components of three oil samples extracted from Illicium verum Hook. f. by steam distillation （SD）, solvent extraction （SE） and supercritical fluid extraction （SFE） were compa...The physical properties and chemical components of three oil samples extracted from Illicium verum Hook. f. by steam distillation （SD）, solvent extraction （SE） and supercritical fluid extraction （SFE） were compared with one another and analyzed by Gas Chromatography-Mass Spectrometry （GC-MS）. The quality parameters of star anise essential oil from SFE were close to that of those came from SD and SE. Although the extraction yield of star anise by SFE （9.2 %） was close to the value from SE （9.3%）, it was yet higher than that came from SD （8.2%）. For sensory evaluation, however, three oils were significantly different. The odor and taste of the products from SFE and SE were generally more natural and vivid than that came from distilled oil. The volatile compound revealed that significant differences of the composition existed in the distilled oil and the oleoresins prepared by SFE and SE.展开更多
Volatile oil was extracted from Illicium Verum Hook. f. by using steam distillation. 41 kinds of compounds were separated and identified by GC/MS, and their relative contents were determined by normalization method. A...Volatile oil was extracted from Illicium Verum Hook. f. by using steam distillation. 41 kinds of compounds were separated and identified by GC/MS, and their relative contents were determined by normalization method. Among 41 identified compounds, there are 14 hydrocarbon components and 22 oxygenated hydrocarbon derivatives, and a small amount of nitrogenous compounds. The main component is anethole, accoun ting for 76.23%, and the other components such as anisyl acetone, anisaldehyde, p allylanisole, p cumic aldehyde and p allylpen take up more than 10%.展开更多
[Objectives]To optimize the ultrasonic-assisted extraction process for total flavonoids in Primula sikkimensis Hook.[Methods]The effects of ethanol volume fraction,extraction time,extraction temperature,ultrasonic tim...[Objectives]To optimize the ultrasonic-assisted extraction process for total flavonoids in Primula sikkimensis Hook.[Methods]The effects of ethanol volume fraction,extraction time,extraction temperature,ultrasonic time and solid-to-liquid ratio on the yield of total flavonoids were investigated by single factor method,and the extraction process for total flavonoids in P.sikkimensis was optimized by Box-Behnken experimental design.[Results]The optimal extraction process for total flavonoids in P.sikkimensis was ethanol volume fraction 45%,extraction time 29 min,extraction temperature 80℃,solid-to-liquid 1∶40(g/mL)and ultrasonic time 10 min.Under such conditions,the average yield of total flavonoids in P.sikkimensis was 3.09%.[Conclusions]The optimized extraction process is simple and feasible,and is expected to provide a reference for the extraction of total flavonoids in P.sikkimensis.展开更多
A new diterpenoid was isolated from the ethanolic extract of the dried root bark of Tripterygium wilfordii Hook.f. It is the first example of abietane diterpenoid glycoside isolated from Tripterygium wilfordii Hook.f...A new diterpenoid was isolated from the ethanolic extract of the dried root bark of Tripterygium wilfordii Hook.f. It is the first example of abietane diterpenoid glycoside isolated from Tripterygium wilfordii Hook.f. Its structure was identified to be 11-O-b-D-glucopyranosyl- neotriptophenolide based on spectral methods.展开更多
Safety of a compound Lonicera rupicola Hook. f. et & Thomson injection was evaluated by local irritation experiments including conjunctiva,skin and muscle irritant experiments,and the effect on weight gain was stu...Safety of a compound Lonicera rupicola Hook. f. et & Thomson injection was evaluated by local irritation experiments including conjunctiva,skin and muscle irritant experiments,and the effect on weight gain was studied. The results showed that the compound L. rupicola Hook. f. et & Thomson injection had no irritation to rabbit eyes and weak irritation to rabbit ears,and had relatively strong irritation to the leg muscles of the mice. Its metabolism in mice had no abnormal toxicity.展开更多
SD Twenty adult male rats were equally divided into a contro1 and an experimcntal group.GTW,10 mg/kg per day,was given to the experimental rats through gastric gavage 6 days a week for 8 weeks.To the control rats,the ...SD Twenty adult male rats were equally divided into a contro1 and an experimcntal group.GTW,10 mg/kg per day,was given to the experimental rats through gastric gavage 6 days a week for 8 weeks.To the control rats,the same amount of vehicle was given The animals were sacrificed when they became infertile and the fol1owing parameters of the testis and epididymis were examined:l)DNA(Feulgen′s method),2)RNA(Brachet′s tech-uique),3)LDH-X(Lojda′s method),4)ATPase(Wachstein′s procedure),5)Succinate dehydrc-genase(SDH,Pearson's method),6)Non-specific esterase(NSE,Lojda's technique)and 7)PAS reaction.Routine examination of the epididymal spermatozoa was also carried out.展开更多
Objective:The objective of this study was to investigate the effect of glycosides of Tripterygium wilfordii Hook.F(GTW)on bone erosion in collagen-induced arthritis(CIA)rats and osteoclastogenesis.Materials and Method...Objective:The objective of this study was to investigate the effect of glycosides of Tripterygium wilfordii Hook.F(GTW)on bone erosion in collagen-induced arthritis(CIA)rats and osteoclastogenesis.Materials and Methods:The effects of GTW on bone destruction were assessed through hematoxylin and eosin analyses and tartrate-resistant acid phosphatase(TRAP)staining.In vitro,TRAP staining,F-actin,and quantitative polymerase chain reaction assays were used to evaluate the inhibitory effects of GTW on osteoclast differentiation.In addition,Western blot,immunohistochemistry,and immunofluorescence staining techniques were employed to explore the mechanisms of GTW by determining the expression of interleukin-8(IL-8),C-X-C motif chemokine receptor 2(CXCR2),nuclear factor of activated T cells 1(NFATc1),and p65.Results:GTW slowed the onset of arthritis and reduced arthritis scores.Our mechanistic studies demonstrated that GTW reduced the number of osteoclasts in rats with CIA and significantly suppressed receptor activator of nuclear factor kappa-B ligand-induced osteoclast differentiation,as evidenced by a decrease in TRAP-positive cells,alterations in F-actin rings,and modulation of osteoclast-specific gene expression.The inhibition of IL-8,CXCR2,NFATc1,and p65 activation by GTW was observed in both CIA rats and osteoclasts.Conversely,the introduction of IL-8 into the osteoclast culture system mitigated the effects of GTW on osteoclast differentiation.Conclusions:Our findings suggest that GTW suppressed osteoclastogenesis and bone loss by inhibiting the IL-8/CXCR2 signaling pathway.These results offer valuable insights into the potential therapeutic role of GTW in rheumatoid arthritis and lay the groundwork for future clinical applications.展开更多
BACKGROUND Hook of hamate fractures occur either due to repetitive stress from gripping sports(e.g.,golf,tennis,and baseball),leading to fatigue fracture,or as a result of trauma from falls or other injuries.The recom...BACKGROUND Hook of hamate fractures occur either due to repetitive stress from gripping sports(e.g.,golf,tennis,and baseball),leading to fatigue fracture,or as a result of trauma from falls or other injuries.The recommended treatment involves the excision of bone fragments to facilitate athletes’early return to sports;excision surgery is also performed in trauma cases.However,some patients prefer nonsurgical treatment options,and conservative treatment should be considered.AIM To present a case series of 16 patients conservatively treated for hook of hamate fractures.METHODS This study included 16(11 males and 5 females;right side,6 cases;left side,10)patients who desired conservative treatment and could be followed-up until bone union was achieved.The average age of the patients was 49.6(range:24-72)years.The average time from injury to consultation was 4.3(range:0.2-21.4)weeks.The treatment involved 4 weeks of casting from the forearm to the metacarpophalangeal joint,followed by 8 weeks of splint fixation of the wrist.Follow-up computed tomography scans were performed every 4 weeks.RESULTS Bone union was achieved in all patients.The average duration of casting was 3.7(range:0-5)weeks and that of splint fixation thereafter was 8.6(range:0-28)weeks.The patients did not exhibit joint contractures or range of motion restrictions due to prolonged immobilization.CONCLUSION Conservative treatment with external fixation may be an option for hook of hamate fractures.展开更多
This editorial critically evaluates the landmark study by Tanaka and Yoshii,which demonstrated a 100%union rate with conservative management of hamate hook fractures,challenging the historical preference for surgical ...This editorial critically evaluates the landmark study by Tanaka and Yoshii,which demonstrated a 100%union rate with conservative management of hamate hook fractures,challenging the historical preference for surgical intervention.In contrast to Scheufle et al’s report of 90%-100%failure rates with early surgical approaches,Tanaka and Yoshii’s protocol achieved universal healing despite delayed diagnoses in 25%of cases.Central to this success is the systematic inte-gration of high-resolution computed tomography for early diagnosis and dynamic monitoring of trabecular bone regeneration,significantly reducing missed dia-gnoses and guiding personalized immobilization timelines.The patient-centered strategy—allowing temporary splint removal during low-risk activities—balanced fracture stability with joint mobility preservation,avoiding post-treatment stiff-ness.However,limitations such as small sample size(n=16),selection bias,and insufficient long-term functional data(e.g.,grip strength,return-to-sport metrics)underscore the need for comparative trials.Emerging trends,including adjunct therapies like low-intensity pulsed ultrasound and biologics(e.g.,teriparatide),are proposed to accelerate healing while minimizing immobilization risks.This work redefines conservative fracture management paradigms,emphasizing in-novation without compromising efficacy.Overall,this assessment deepens our understanding of the conservative management of hook fractures and provides evidence-based insights for improved clinical decision-making.展开更多
The hook formation mechanism in continuously cast slabs of ultra-low carbon steel was analyzed in detail through numerical calculations and experimental observations using optical microscopy,and its distribution chara...The hook formation mechanism in continuously cast slabs of ultra-low carbon steel was analyzed in detail through numerical calculations and experimental observations using optical microscopy,and its distribution characteristics were determined.Numerical simulations confirmed that the freezing–overflow mechanism is the primary cause of hook formation.They also revealed that the freezing event occurs unpredictably,while the overflow event takes place during the positive strip time.The average pitch of oscillation marks(OMs)on the slab surface was 8.693 mm,while the theoretical pitch was 8.889 mm,with a difference of approximately 2%.This discrepancy primarily results from varying degrees of overflow,which affects the morphology of the OMs and the positions of their deepest points.Notably,this result further confirmed that the freezing and overflow in the meniscus were indeed caused by the periodic oscillation of the mold.Higher superheat hindered hook formation,leading to a negative correlation between the hook depth distribution around the slab and the temperature distribution within the mold.Therefore,the depth of the corner hook was greater than that of other positions,which was caused by the intensified cooling effect of the corner.Moreover,key factors influencing hook development were analyzed,providing insights into transient fluid flow and heat transfer characteristics within the mold.Transient fluid flow and heat transfer contributed to the randomness and tendency of hook formation.This randomness was reflected in the varying angles of the hooks,whereas the tendency was evident in the negative correlation between superheat and hook length.Based on the randomness and tendency of hook formation and its profile characteristics,a new method for controlling hook depth based on“sine law”is proposed.展开更多
During the continuous casting process of low carbon steel,the solidified hook formed in the mold has great effects on the surface quality of the cast slab.Some factory experiments have been conducted to investigate th...During the continuous casting process of low carbon steel,the solidified hook formed in the mold has great effects on the surface quality of the cast slab.Some factory experiments have been conducted to investigate the microscopic characteristics and reveal the influence of process parameters on solidified hooks.The depth of the hooks showed a positive correlation with the deflection angle,length,and oscillation mark(OM)depth,which indicates that the OM depth can serve as an approximate indicator for evaluating the depth of the solidified hooks.On the wide and narrow faces of the cast slab,the depth of the solidified hooks and the temperature distribution in the mold show opposite trends,with lower depths of solidified hooks at positions with higher temperatures.In addition,the influence of process parameters on solidified hooks was analyzed.With the increase in superheat,not only the depth of solidified hooks gradually decreases,but also the ratio of depression-typed marks increases.Increasing casting speed and decreasing immersion depth of the submerged entry nozzle will both lead to a decrease in the depth of the solidified hook.展开更多
文摘OBJECTIVE The inhibitory effect of active ingredients of Tripterygium wilfordii Hook.F.(TWHF)(celastrol,triptolide,triptonide,wilforlide A,wilforgine and wilforine)on human carboxylester⁃ase 1(CES1)and CES2 was detected to investigate the herb-drug interactions(HDIs)of TWHF.METHODS Human liver microsomes catalysed hydrolysis of 2-(2-benzoyl-3-methoxyphenyl)benzothi⁃azole(BMBT)and fluorescein diacetate(FD)were used as the probe reaction to phenotype the activity of CES1 and CES2,respectively.The residual activities of CES1 and CES2 were detected by ultrahigh performance liquid chromatography(UPLC)after intervention with celastrol,triptolide,triptonide,wilforlide A,wilforgine and wilforine(100μmol·L^(-1)).Kinetics analysis,involving half inhibitory concentra⁃tion(IC_(50)),inhibition type and kinetic parameter(Ki),and in vitro-in vivo extrapolation(IVIVE),was carried out to predict the HDIs between these compounds and CES-metabolizing drugs.Molecular docking was performed to analyze the ligand-enzyme interaction.RESULTS Out of the six main con⁃stituents of TWHF,only celastrol exhibited strong inhibition towards both CES1 and CES2,with the inhibitory rates of 97.45%(P<0.05)and 95.62%(P<0.05),respectively.The IC_(50)was 9.95 and 4.02 mol·L^(-1),respectively,and the types of inhibition were all non-competitive inhibition.Based on the kinetics analysis,the Ki values were calculated to be 5.10 and 10.55μmol·L^(-1)for the inhibition of celastrol on CES1 and CES2,respectively.IVIVE indicated that celastrol might disturb the metabolic hydrolysis of clinical drugs in vivo by inhibiting CES1.Molecular docking results showed that hydrogen bonds and hydrophobic contacts contributed to the interaction of celastrol and CESs.CONCLUSION The inhibitory effect of celastrol on CES1 and CES2 might cause HDIs with clinical drugs hydrolysed by CESs.
基金Supported by the Science and Technology Key Project of Guangxi Province (0424008-1C)
文摘The physical properties and chemical components of three oil samples extracted from Illicium verum Hook. f. by steam distillation （SD）, solvent extraction （SE） and supercritical fluid extraction （SFE） were compared with one another and analyzed by Gas Chromatography-Mass Spectrometry （GC-MS）. The quality parameters of star anise essential oil from SFE were close to that of those came from SD and SE. Although the extraction yield of star anise by SFE （9.2 %） was close to the value from SE （9.3%）, it was yet higher than that came from SD （8.2%）. For sensory evaluation, however, three oils were significantly different. The odor and taste of the products from SFE and SE were generally more natural and vivid than that came from distilled oil. The volatile compound revealed that significant differences of the composition existed in the distilled oil and the oleoresins prepared by SFE and SE.
基金ScienceFoundationofEducationforHunanProvince (No .0 0C32 4 )
文摘Volatile oil was extracted from Illicium Verum Hook. f. by using steam distillation. 41 kinds of compounds were separated and identified by GC/MS, and their relative contents were determined by normalization method. Among 41 identified compounds, there are 14 hydrocarbon components and 22 oxygenated hydrocarbon derivatives, and a small amount of nitrogenous compounds. The main component is anethole, accoun ting for 76.23%, and the other components such as anisyl acetone, anisaldehyde, p allylanisole, p cumic aldehyde and p allylpen take up more than 10%.
基金Supported by Project of Sichuan College of Traditional Chinese Medicine(18ZRYB04).
文摘[Objectives]To optimize the ultrasonic-assisted extraction process for total flavonoids in Primula sikkimensis Hook.[Methods]The effects of ethanol volume fraction,extraction time,extraction temperature,ultrasonic time and solid-to-liquid ratio on the yield of total flavonoids were investigated by single factor method,and the extraction process for total flavonoids in P.sikkimensis was optimized by Box-Behnken experimental design.[Results]The optimal extraction process for total flavonoids in P.sikkimensis was ethanol volume fraction 45%,extraction time 29 min,extraction temperature 80℃,solid-to-liquid 1∶40(g/mL)and ultrasonic time 10 min.Under such conditions,the average yield of total flavonoids in P.sikkimensis was 3.09%.[Conclusions]The optimized extraction process is simple and feasible,and is expected to provide a reference for the extraction of total flavonoids in P.sikkimensis.
文摘A new diterpenoid was isolated from the ethanolic extract of the dried root bark of Tripterygium wilfordii Hook.f. It is the first example of abietane diterpenoid glycoside isolated from Tripterygium wilfordii Hook.f. Its structure was identified to be 11-O-b-D-glucopyranosyl- neotriptophenolide based on spectral methods.
基金Supported by Project of Science and Technology Department of Sichuan Province,China(2016KZ0007)Innovative Scientific Research Project for Postgraduates of Southwest Minzu University(CX2018SZ44)
文摘Safety of a compound Lonicera rupicola Hook. f. et & Thomson injection was evaluated by local irritation experiments including conjunctiva,skin and muscle irritant experiments,and the effect on weight gain was studied. The results showed that the compound L. rupicola Hook. f. et & Thomson injection had no irritation to rabbit eyes and weak irritation to rabbit ears,and had relatively strong irritation to the leg muscles of the mice. Its metabolism in mice had no abnormal toxicity.
文摘SD Twenty adult male rats were equally divided into a contro1 and an experimcntal group.GTW,10 mg/kg per day,was given to the experimental rats through gastric gavage 6 days a week for 8 weeks.To the control rats,the same amount of vehicle was given The animals were sacrificed when they became infertile and the fol1owing parameters of the testis and epididymis were examined:l)DNA(Feulgen′s method),2)RNA(Brachet′s tech-uique),3)LDH-X(Lojda′s method),4)ATPase(Wachstein′s procedure),5)Succinate dehydrc-genase(SDH,Pearson's method),6)Non-specific esterase(NSE,Lojda's technique)and 7)PAS reaction.Routine examination of the epididymal spermatozoa was also carried out.
基金supported by the National Natural Science Foundation of China(82330124,81974526,and 81873068)Natural Science Foundation of Beijing Municipality(7192139)。
文摘Objective:The objective of this study was to investigate the effect of glycosides of Tripterygium wilfordii Hook.F(GTW)on bone erosion in collagen-induced arthritis(CIA)rats and osteoclastogenesis.Materials and Methods:The effects of GTW on bone destruction were assessed through hematoxylin and eosin analyses and tartrate-resistant acid phosphatase(TRAP)staining.In vitro,TRAP staining,F-actin,and quantitative polymerase chain reaction assays were used to evaluate the inhibitory effects of GTW on osteoclast differentiation.In addition,Western blot,immunohistochemistry,and immunofluorescence staining techniques were employed to explore the mechanisms of GTW by determining the expression of interleukin-8(IL-8),C-X-C motif chemokine receptor 2(CXCR2),nuclear factor of activated T cells 1(NFATc1),and p65.Results:GTW slowed the onset of arthritis and reduced arthritis scores.Our mechanistic studies demonstrated that GTW reduced the number of osteoclasts in rats with CIA and significantly suppressed receptor activator of nuclear factor kappa-B ligand-induced osteoclast differentiation,as evidenced by a decrease in TRAP-positive cells,alterations in F-actin rings,and modulation of osteoclast-specific gene expression.The inhibition of IL-8,CXCR2,NFATc1,and p65 activation by GTW was observed in both CIA rats and osteoclasts.Conversely,the introduction of IL-8 into the osteoclast culture system mitigated the effects of GTW on osteoclast differentiation.Conclusions:Our findings suggest that GTW suppressed osteoclastogenesis and bone loss by inhibiting the IL-8/CXCR2 signaling pathway.These results offer valuable insights into the potential therapeutic role of GTW in rheumatoid arthritis and lay the groundwork for future clinical applications.
文摘BACKGROUND Hook of hamate fractures occur either due to repetitive stress from gripping sports(e.g.,golf,tennis,and baseball),leading to fatigue fracture,or as a result of trauma from falls or other injuries.The recommended treatment involves the excision of bone fragments to facilitate athletes’early return to sports;excision surgery is also performed in trauma cases.However,some patients prefer nonsurgical treatment options,and conservative treatment should be considered.AIM To present a case series of 16 patients conservatively treated for hook of hamate fractures.METHODS This study included 16(11 males and 5 females;right side,6 cases;left side,10)patients who desired conservative treatment and could be followed-up until bone union was achieved.The average age of the patients was 49.6(range:24-72)years.The average time from injury to consultation was 4.3(range:0.2-21.4)weeks.The treatment involved 4 weeks of casting from the forearm to the metacarpophalangeal joint,followed by 8 weeks of splint fixation of the wrist.Follow-up computed tomography scans were performed every 4 weeks.RESULTS Bone union was achieved in all patients.The average duration of casting was 3.7(range:0-5)weeks and that of splint fixation thereafter was 8.6(range:0-28)weeks.The patients did not exhibit joint contractures or range of motion restrictions due to prolonged immobilization.CONCLUSION Conservative treatment with external fixation may be an option for hook of hamate fractures.
文摘This editorial critically evaluates the landmark study by Tanaka and Yoshii,which demonstrated a 100%union rate with conservative management of hamate hook fractures,challenging the historical preference for surgical intervention.In contrast to Scheufle et al’s report of 90%-100%failure rates with early surgical approaches,Tanaka and Yoshii’s protocol achieved universal healing despite delayed diagnoses in 25%of cases.Central to this success is the systematic inte-gration of high-resolution computed tomography for early diagnosis and dynamic monitoring of trabecular bone regeneration,significantly reducing missed dia-gnoses and guiding personalized immobilization timelines.The patient-centered strategy—allowing temporary splint removal during low-risk activities—balanced fracture stability with joint mobility preservation,avoiding post-treatment stiff-ness.However,limitations such as small sample size(n=16),selection bias,and insufficient long-term functional data(e.g.,grip strength,return-to-sport metrics)underscore the need for comparative trials.Emerging trends,including adjunct therapies like low-intensity pulsed ultrasound and biologics(e.g.,teriparatide),are proposed to accelerate healing while minimizing immobilization risks.This work redefines conservative fracture management paradigms,emphasizing in-novation without compromising efficacy.Overall,this assessment deepens our understanding of the conservative management of hook fractures and provides evidence-based insights for improved clinical decision-making.
基金financially supported by the National Natural Science Foundation of China(No.52174306)the Fundamental Research Funds for the Central Universities(Nos.N2225023 and N2425006)the Basic Research Projects of Liaoning Provincial Department of Education(No.LJ212410148027)。
文摘The hook formation mechanism in continuously cast slabs of ultra-low carbon steel was analyzed in detail through numerical calculations and experimental observations using optical microscopy,and its distribution characteristics were determined.Numerical simulations confirmed that the freezing–overflow mechanism is the primary cause of hook formation.They also revealed that the freezing event occurs unpredictably,while the overflow event takes place during the positive strip time.The average pitch of oscillation marks(OMs)on the slab surface was 8.693 mm,while the theoretical pitch was 8.889 mm,with a difference of approximately 2%.This discrepancy primarily results from varying degrees of overflow,which affects the morphology of the OMs and the positions of their deepest points.Notably,this result further confirmed that the freezing and overflow in the meniscus were indeed caused by the periodic oscillation of the mold.Higher superheat hindered hook formation,leading to a negative correlation between the hook depth distribution around the slab and the temperature distribution within the mold.Therefore,the depth of the corner hook was greater than that of other positions,which was caused by the intensified cooling effect of the corner.Moreover,key factors influencing hook development were analyzed,providing insights into transient fluid flow and heat transfer characteristics within the mold.Transient fluid flow and heat transfer contributed to the randomness and tendency of hook formation.This randomness was reflected in the varying angles of the hooks,whereas the tendency was evident in the negative correlation between superheat and hook length.Based on the randomness and tendency of hook formation and its profile characteristics,a new method for controlling hook depth based on“sine law”is proposed.
基金the financial support of National Key Research and Development Plan(No.2021YFB3702000)National Natural Science of China(Nos.52074076,52174306 and U20A20272)Fundamental Research Funds for the Central Universities(Nos.N2225023 and N2425006).Author information。
文摘During the continuous casting process of low carbon steel,the solidified hook formed in the mold has great effects on the surface quality of the cast slab.Some factory experiments have been conducted to investigate the microscopic characteristics and reveal the influence of process parameters on solidified hooks.The depth of the hooks showed a positive correlation with the deflection angle,length,and oscillation mark(OM)depth,which indicates that the OM depth can serve as an approximate indicator for evaluating the depth of the solidified hooks.On the wide and narrow faces of the cast slab,the depth of the solidified hooks and the temperature distribution in the mold show opposite trends,with lower depths of solidified hooks at positions with higher temperatures.In addition,the influence of process parameters on solidified hooks was analyzed.With the increase in superheat,not only the depth of solidified hooks gradually decreases,but also the ratio of depression-typed marks increases.Increasing casting speed and decreasing immersion depth of the submerged entry nozzle will both lead to a decrease in the depth of the solidified hook.
