This paper employs a velocity plus displacement（V＋D）-based equivalent force control（EFC） method to solve the velocity/displacement difference equation in a real-time substructure test. This method uses type 2 fee...This paper employs a velocity plus displacement（V＋D）-based equivalent force control（EFC） method to solve the velocity/displacement difference equation in a real-time substructure test. This method uses type 2 feedback control loops to replace mathematical iteration to solve the nonlinear dynamic equation. A spectral radius analysis of the amplification matrix shows that the type 2 EFC-explicit, Newmark-β method has beneficial numerical characteristics for this method. Its stability limit of Ω = 2 remains unchanged regardless of the system damping because the velocity is achieved with very high accuracy during simulation. In contrast, the stability limits of the central difference method using direct velocity prediction and the EFC-average acceleration method with linear interpolation are shown to decrease with an increase in system damping. In fact, the EFC-average acceleration method is shown to change from unconditionally stable to conditionally stable. We also show that if an over-damped system with a damping ratio of 1.05 is considered, the stability limit is reduced to Ω =1.45. Finally, the results from an experiment with a single-degree-of-freedom structure installed with a magneto-rheological（MR） damper are presented. The results demonstrate that the proposed method is able to follow both displacement and velocity commands with moderate accuracy, resulting in improved test performance and accuracy for structures that are sensitive to both velocity and displacement inputs. Although the findings of the study are promising, additional test data and several further improvements will be required to draw general conclusions.展开更多
Introduction:Rotatory chair testing has been used to evaluate horizontal canal function.Frequently used tests include sinusoidal harmonic acceleration test(SHAT)and velocity step test(VST).Objectives:Assessment of age...Introduction:Rotatory chair testing has been used to evaluate horizontal canal function.Frequently used tests include sinusoidal harmonic acceleration test(SHAT)and velocity step test(VST).Objectives:Assessment of age effect on the SHAT and VST and assessment of test-retest reliability of the parameters of those two tests.Methods:A prospective study was performed on 100 subjects with no ear or vestibular complaints and normal vestibular evaluation.They were divided into two groups;Group A:below 50 years of age and Group B:50 years of age or above.SHAT was presented at frequencies 0.02,0.04,0.08,0.16,0.32,0.64 Hz with a peak velocity of 60°/s.VST was performed using a maximum velocity of 100°/s with acceleration and deceleration of 200°/s2.Thirty subjects were tested twice to assess reliability.Results:Study participants ranged in age from 20 to 67 years.Regarding group A,the mean age was30.92±7.31 and 55.36±4.61 for group B.No significant differences were found in SHAT parameters between the two groups.As well,there was no significant difference in VST per-rotatory time constant,however,post-rotatory time constant was significantly longer for Group B(P value<0.05).Intraclass correlation coefficient(ICC)values showed moderate to good reliability(ICC 0.5800.818)for SHAT parameters for the lower frequencies and indicated moderate reliability for VST time constant(ICC 0.5090.652).Conclusions:Age has no significant effect on the parameters of SHAT and VST.Test-retest reliability is generally good for both tests.展开更多
The basic technology and properties of the brake blocks made of modified needle-like wollastonite and fibrous sepiolite were intensively researched.The impact strengthes and fixed velocity friction of the brake blocks...The basic technology and properties of the brake blocks made of modified needle-like wollastonite and fibrous sepiolite were intensively researched.The impact strengthes and fixed velocity friction of the brake blocks prepared by different recipes were tested. The testing results show that it is feasible for needle-like wollastonite and fibrous sepiolite to take the place of asbestos as the reinforced materials of friction materials.The braking effect of the brake blocks is the best when the ratio of the needle-like wollastonite to the fibrous sepiolite was 1∶6.展开更多
No shale-rock physical model has been established in the observation coordinate system.To this end,this paper carried out anisotropic wave velocity tests on shale rock and compared the Thomsen,Daley,and Berryman solut...No shale-rock physical model has been established in the observation coordinate system.To this end,this paper carried out anisotropic wave velocity tests on shale rock and compared the Thomsen,Daley,and Berryman solutions to characterize anisotropic acoustic wave velocity.Finally,the Daley solution was selected.Based on basic rock physical models,such as SCA and DEM methods,and combined with the Daley solution,an anisotropic shale-rock physical model was established in the observation coordinate system and applied in Well B1 in the Luzhou area,Sichuan Basin.Our research conclusions were as follows:1.for the samples from the same core,the P-wave velocities in three directions were in the order VP11>VP45>VP33,shear wave velocity VS11 was the largest,but VS33 and VS45 did not follow the law of Vs33>Vs45 for some samples;2.the Daley solution,which not only considers the accuracy requirements but also has a complete expression of P-,SV-,and SH-waves,is most suitable for characterization of anisotropic wave velocity in this study area;3.the rock physical model constructed in the observation coordinate system has high accuracy,in which the absolute value of the relative error of the P-wave slowness was between 0%and 5.05%(0.55%on average),and that of shear-wave slowness was between 0%and 6.05%(0.59%on average);4.the acoustic waves recorded in Well B1 in the observation coordinate system were very different from those in the constitutive coordinate system.The relative difference of the P-wave was between 6.76%and 30.84%(14.68%on average),and that of the S-wave was between 7.00%and 23.44%(13.99%on average).The acoustic slowness measured in the observation coordinate system,such as in a deviated well or a horizontal well section,must be converted to the constitutive coordinate system before it can be used in subsequent engineering applications;5.the anisotropic shale-rock physical model built in the observation coordinate system proposed in this paper can provide basic data and guidance for subsequent pore pressure prediction,geomechanical modeling,and fracturing stimulation design for deviated and horizontal wells.展开更多
Objective:To observe the preventive and treatment effects of warming needle therapy on peripheral neuropathy after albumin-bound paclitaxel plus cisplatin chemotherapy.Methods:Eighty patients who received albumin-boun...Objective:To observe the preventive and treatment effects of warming needle therapy on peripheral neuropathy after albumin-bound paclitaxel plus cisplatin chemotherapy.Methods:Eighty patients who received albumin-bound paclitaxel plus cisplatin chemotherapy after being diagnosed with cancer were divided into an observation group and a control group using the simple random allocation table method,with 40 cases in each group.The control group received methylcobalamin dispersible tablets via oral administration,and the observation group received warming needle therapy.They were observed for the incidence of chemotherapy-induced peripheral neuropathy(CIPN),Levi’s specific sensory neurotoxicity grading,brief pain inventory(BPI)score,nerve conduction velocities of the limbs,and traditional Chinese medicine(TCM)symptom scores before treatment,at the 21st day of the first cycle of chemotherapy(D1),and the 21st day of the second chemotherapy cycle(D2).The clinical efficacy was assessed at D2.Results:The incidence of CIPN was 92.5%in the control group,higher than 75.0%in the observation group(P<0.05).At D2,the number of people graded 0 on Levi’s specific sensory neurotoxicity grading was larger in the observation group than in the control group,and the number of those graded 2 was smaller in the observation group(P<0.05);the observation group had a higher markedly effective rate than the control group(P<0.05).At D2,the BPI general score,BPI pain intensity score,and BPI pain interference score significantly dropped in the observation group compared to those before treatment(P<0.05).At D1,the motor nerve conduction velocity(MNCV)and sensory nerve conduction velocity(SNCV)of the limbs decreased in both groups compared to those before treatment;at D2,the MNCV and SNCV increased in the two groups compared to D1 and were higher in the observation group than in the control group(P<0.05).At D1,the TCM symptom scores increased in both groups compared to those before treatment,and the observation group was lower than the control group in comparing the scores of numbness in the extremities and poor appetite(P<0.05).At D2,the observation group showed decreases in all TCM symptom scores compared to D1 except for the scores of nausea and vomiting and poor appetite(P<0.05),while the control group had no significant changes in the TCM symptom scores compared to D1(P>0.05);the observation group was lower than the control group in comparing each symptom score(P<0.05).There were no significant adverse reactions in either group over the study period.Conclusion:Compared to oral administration of methylcobalamin dispersible tablets,warming needle therapy shows certain strengths in managing CIPN after albumin-bound paclitaxel plus cisplatin chemotherapy,and it can better improve chemotherapy-induced gastrointestinal reactions.展开更多
基金Scientific Research Fund of the Institute of Engineering Mechanics,CEA under Grant No.2016B09,2017A02 and 2016A06the National Natural Science Foundation of China under Grant No,51378478,51408565,51678538 and 51161120360the National ScienceTechnology Support Plan Projects(2016YFC0701106)
文摘This paper employs a velocity plus displacement（V＋D）-based equivalent force control（EFC） method to solve the velocity/displacement difference equation in a real-time substructure test. This method uses type 2 feedback control loops to replace mathematical iteration to solve the nonlinear dynamic equation. A spectral radius analysis of the amplification matrix shows that the type 2 EFC-explicit, Newmark-β method has beneficial numerical characteristics for this method. Its stability limit of Ω = 2 remains unchanged regardless of the system damping because the velocity is achieved with very high accuracy during simulation. In contrast, the stability limits of the central difference method using direct velocity prediction and the EFC-average acceleration method with linear interpolation are shown to decrease with an increase in system damping. In fact, the EFC-average acceleration method is shown to change from unconditionally stable to conditionally stable. We also show that if an over-damped system with a damping ratio of 1.05 is considered, the stability limit is reduced to Ω =1.45. Finally, the results from an experiment with a single-degree-of-freedom structure installed with a magneto-rheological（MR） damper are presented. The results demonstrate that the proposed method is able to follow both displacement and velocity commands with moderate accuracy, resulting in improved test performance and accuracy for structures that are sensitive to both velocity and displacement inputs. Although the findings of the study are promising, additional test data and several further improvements will be required to draw general conclusions.
文摘Introduction:Rotatory chair testing has been used to evaluate horizontal canal function.Frequently used tests include sinusoidal harmonic acceleration test(SHAT)and velocity step test(VST).Objectives:Assessment of age effect on the SHAT and VST and assessment of test-retest reliability of the parameters of those two tests.Methods:A prospective study was performed on 100 subjects with no ear or vestibular complaints and normal vestibular evaluation.They were divided into two groups;Group A:below 50 years of age and Group B:50 years of age or above.SHAT was presented at frequencies 0.02,0.04,0.08,0.16,0.32,0.64 Hz with a peak velocity of 60°/s.VST was performed using a maximum velocity of 100°/s with acceleration and deceleration of 200°/s2.Thirty subjects were tested twice to assess reliability.Results:Study participants ranged in age from 20 to 67 years.Regarding group A,the mean age was30.92±7.31 and 55.36±4.61 for group B.No significant differences were found in SHAT parameters between the two groups.As well,there was no significant difference in VST per-rotatory time constant,however,post-rotatory time constant was significantly longer for Group B(P value<0.05).Intraclass correlation coefficient(ICC)values showed moderate to good reliability(ICC 0.5800.818)for SHAT parameters for the lower frequencies and indicated moderate reliability for VST time constant(ICC 0.5090.652).Conclusions:Age has no significant effect on the parameters of SHAT and VST.Test-retest reliability is generally good for both tests.
文摘The basic technology and properties of the brake blocks made of modified needle-like wollastonite and fibrous sepiolite were intensively researched.The impact strengthes and fixed velocity friction of the brake blocks prepared by different recipes were tested. The testing results show that it is feasible for needle-like wollastonite and fibrous sepiolite to take the place of asbestos as the reinforced materials of friction materials.The braking effect of the brake blocks is the best when the ratio of the needle-like wollastonite to the fibrous sepiolite was 1∶6.
基金supported by the Post Doctoral Project of Southwest Oil and Gas Field Research on Geomechanics and Effective Fracturing Factors of Deep Shale” (No. 20210302-31)the Scientific Research Project of Southwest Oil and Gas Field Branch “Geological Engineering Integration of Well Block Yang101”。
文摘No shale-rock physical model has been established in the observation coordinate system.To this end,this paper carried out anisotropic wave velocity tests on shale rock and compared the Thomsen,Daley,and Berryman solutions to characterize anisotropic acoustic wave velocity.Finally,the Daley solution was selected.Based on basic rock physical models,such as SCA and DEM methods,and combined with the Daley solution,an anisotropic shale-rock physical model was established in the observation coordinate system and applied in Well B1 in the Luzhou area,Sichuan Basin.Our research conclusions were as follows:1.for the samples from the same core,the P-wave velocities in three directions were in the order VP11>VP45>VP33,shear wave velocity VS11 was the largest,but VS33 and VS45 did not follow the law of Vs33>Vs45 for some samples;2.the Daley solution,which not only considers the accuracy requirements but also has a complete expression of P-,SV-,and SH-waves,is most suitable for characterization of anisotropic wave velocity in this study area;3.the rock physical model constructed in the observation coordinate system has high accuracy,in which the absolute value of the relative error of the P-wave slowness was between 0%and 5.05%(0.55%on average),and that of shear-wave slowness was between 0%and 6.05%(0.59%on average);4.the acoustic waves recorded in Well B1 in the observation coordinate system were very different from those in the constitutive coordinate system.The relative difference of the P-wave was between 6.76%and 30.84%(14.68%on average),and that of the S-wave was between 7.00%and 23.44%(13.99%on average).The acoustic slowness measured in the observation coordinate system,such as in a deviated well or a horizontal well section,must be converted to the constitutive coordinate system before it can be used in subsequent engineering applications;5.the anisotropic shale-rock physical model built in the observation coordinate system proposed in this paper can provide basic data and guidance for subsequent pore pressure prediction,geomechanical modeling,and fracturing stimulation design for deviated and horizontal wells.
文摘Objective:To observe the preventive and treatment effects of warming needle therapy on peripheral neuropathy after albumin-bound paclitaxel plus cisplatin chemotherapy.Methods:Eighty patients who received albumin-bound paclitaxel plus cisplatin chemotherapy after being diagnosed with cancer were divided into an observation group and a control group using the simple random allocation table method,with 40 cases in each group.The control group received methylcobalamin dispersible tablets via oral administration,and the observation group received warming needle therapy.They were observed for the incidence of chemotherapy-induced peripheral neuropathy(CIPN),Levi’s specific sensory neurotoxicity grading,brief pain inventory(BPI)score,nerve conduction velocities of the limbs,and traditional Chinese medicine(TCM)symptom scores before treatment,at the 21st day of the first cycle of chemotherapy(D1),and the 21st day of the second chemotherapy cycle(D2).The clinical efficacy was assessed at D2.Results:The incidence of CIPN was 92.5%in the control group,higher than 75.0%in the observation group(P<0.05).At D2,the number of people graded 0 on Levi’s specific sensory neurotoxicity grading was larger in the observation group than in the control group,and the number of those graded 2 was smaller in the observation group(P<0.05);the observation group had a higher markedly effective rate than the control group(P<0.05).At D2,the BPI general score,BPI pain intensity score,and BPI pain interference score significantly dropped in the observation group compared to those before treatment(P<0.05).At D1,the motor nerve conduction velocity(MNCV)and sensory nerve conduction velocity(SNCV)of the limbs decreased in both groups compared to those before treatment;at D2,the MNCV and SNCV increased in the two groups compared to D1 and were higher in the observation group than in the control group(P<0.05).At D1,the TCM symptom scores increased in both groups compared to those before treatment,and the observation group was lower than the control group in comparing the scores of numbness in the extremities and poor appetite(P<0.05).At D2,the observation group showed decreases in all TCM symptom scores compared to D1 except for the scores of nausea and vomiting and poor appetite(P<0.05),while the control group had no significant changes in the TCM symptom scores compared to D1(P>0.05);the observation group was lower than the control group in comparing each symptom score(P<0.05).There were no significant adverse reactions in either group over the study period.Conclusion:Compared to oral administration of methylcobalamin dispersible tablets,warming needle therapy shows certain strengths in managing CIPN after albumin-bound paclitaxel plus cisplatin chemotherapy,and it can better improve chemotherapy-induced gastrointestinal reactions.
