The sliding chairs are important components that support the switch rail conversion in the railway turnout.Due to the harsh environmental erosion and the attack from the wheel vibration,the failure rate of the sliding...The sliding chairs are important components that support the switch rail conversion in the railway turnout.Due to the harsh environmental erosion and the attack from the wheel vibration,the failure rate of the sliding chairs accounts for up to 10%of the total failure number in turnout.However,there is little research carried out in the existing literature to diagnose the deterioration states of the sliding chairs.To fill out this gap,by utilizing the images containing the sliding chairs,we propose an improved You Only Look Once version 7(YOLOv7)to identify the state of the sliding chairs.Specifically,to meet the challenge brought by the small inter-class differences among the sliding chair states,we first integrate the Convolutional Block Attention Module(CBAM)into the YOLOv7 backbone to screen the information conducive to state identification.Then,an extra detector for a small object is customized into the YOLOv7 network in order to detect the small-scale sliding chairs in images.Meanwhile,we revise the localization loss in the objective function as the Efficient Intersection over Union(EIoU)to optimize the design of the aspect ratio,which helps the localization of the sliding chairs.Next,to address the issue caused by the varying scales of the sliding chairs,we employ K-means++to optimize the priori selection of the initial anchor boxes.Finally,based on the images collected from real-world turnouts,the proposed method is verified and the results show that our method outperforms the basic YOLOv7 in the state identification of the sliding chairs with 4%improvements in terms of both mean Average Precision@0.5(mAP@0.5)and F1-score.展开更多
Using a sample of Chinese family firms listed from 1999 to 2014, we investigate the relationship between non-family leadership and firm performance. We find that firms with a non-family member as board chair perform s...Using a sample of Chinese family firms listed from 1999 to 2014, we investigate the relationship between non-family leadership and firm performance. We find that firms with a non-family member as board chair perform significantly worse than firms whose chair belongs to the family. Moreover, we show that the underperformance of nonfamily-chair firms is more pronounced when firms are under weaker outside monitoring and when the controlling families care less about family business longevity. The negative effect of a non-family chair is robust to a variety of endogeneity tests. We also dismiss alternative explanations other than concern for reputation. Overall, our empirical results suggest that the social norms regarding family reputation are important in shaping the controlling shareholders＇ expropriation incentives and firm performance.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 development of insertion-type anodes is the key to designing“rocking chair”zinc-ion batteries.However,there is rare report on high mass loading anode with high performances.Here,{001}-oriented Bi OCl nanosheets ...The development of insertion-type anodes is the key to designing“rocking chair”zinc-ion batteries.However,there is rare report on high mass loading anode with high performances.Here,{001}-oriented Bi OCl nanosheets with Sn doping are proposed as a promising insertion-type anode.The designs of cross-linked CNTs conductive network,{001}-oriented nanosheet,and Sn doping significantly enhance ion/electron transport,proved via experimental tests and theoretical calculations(density of states and diffusion barrier).The H^(+)/Zn^(2+)synergistic co-insertion mechanism is proved via ex situ XRD,Raman,XPS,and SEM tests.Accordingly,this optimized electrode delivers a high reversible capacity of 194 m A h g^(-1)at 0.1 A g^(-1)with a voltage of≈0.37 V and an impressive cyclability with 128 m A h g^(-1)over 2500 cycles at 1 A g^(-1).It also shows satisfactory performances at an ultrahigh mass loading of 10 mg cm^(-2).Moreover,the Sn-Bi OCl//MnO_(2)full cell displays a reversible capacity of 85 m A h g^(-1)at 0.2 A g^(-1)during cyclic test.展开更多
For the past six decades,Uganda and China have enjoyed remarkable bilateral relations and Uganda being recently elected to chair G77+China mechanism is set to drive the relationship to even greater heights.That’s acc...For the past six decades,Uganda and China have enjoyed remarkable bilateral relations and Uganda being recently elected to chair G77+China mechanism is set to drive the relationship to even greater heights.That’s according to Uganda’s First Deputy Prime Minister Rebecca Kadaga,who made the remarks recently while speaking at an event to mark the 74th anniversary of the founding of the People’s Republic of China.In response,the charge d’affaires at the Chinese Embassy in Uganda,Fan Xuecheng,toasted the long-standing friendship between the peoples of China and Uganda.展开更多
目的研究星状神经节阻滞对肩关节镜手术沙滩椅位脑血流动力学改变的影响。方法取择期行沙滩椅位肩关节镜手术患者40例,随机分为治疗组T组和对照组C组各20例,T组术前行超声引导下SGB,对比两组患者术中生命体征、BIS值、脑氧合饱和度(rSO_...目的研究星状神经节阻滞对肩关节镜手术沙滩椅位脑血流动力学改变的影响。方法取择期行沙滩椅位肩关节镜手术患者40例,随机分为治疗组T组和对照组C组各20例,T组术前行超声引导下SGB,对比两组患者术中生命体征、BIS值、脑氧合饱和度(rSO_(2))、不同时段大脑中动脉血流频谱图像、术后7 d ULCA评分、MMSE评分、RBANS总分,将两组数据进行统计学处理分析。结果T组比C组患者术中生命体征变化波动较小,差异有统计学意义(P<0.05)。不同时段rSO_(2)基本保持在相同水平,差异无统计学意义(P>0.05);T组患者大脑中动脉血流流速比C组要低,但血管内径要大,根据公式得出T组患者在不同时间段血流量都要比C组同时段的多,比较差异有统计学意义(P<0.05)。两组术后7 d ULCA评分、MMSE评分、RBANS总分对比T组明显较高,差异有统计学意义(P<0.05)。结论对沙滩椅位行肩关节镜手术的患者术前实施星状神经阻滞术具有增加脑血供及脑保护作用且对患者术后关节功能恢复有良好的促进作用,有临床推广实用价值。展开更多
基金supported by the National Key R&D Program of China(2021YFF0501102)the National Natural Science Foundation of China(52372308,U2368202,U1934219,52202392,52022010,U22A2046,52172322,and 62271486).
文摘The sliding chairs are important components that support the switch rail conversion in the railway turnout.Due to the harsh environmental erosion and the attack from the wheel vibration,the failure rate of the sliding chairs accounts for up to 10%of the total failure number in turnout.However,there is little research carried out in the existing literature to diagnose the deterioration states of the sliding chairs.To fill out this gap,by utilizing the images containing the sliding chairs,we propose an improved You Only Look Once version 7(YOLOv7)to identify the state of the sliding chairs.Specifically,to meet the challenge brought by the small inter-class differences among the sliding chair states,we first integrate the Convolutional Block Attention Module(CBAM)into the YOLOv7 backbone to screen the information conducive to state identification.Then,an extra detector for a small object is customized into the YOLOv7 network in order to detect the small-scale sliding chairs in images.Meanwhile,we revise the localization loss in the objective function as the Efficient Intersection over Union(EIoU)to optimize the design of the aspect ratio,which helps the localization of the sliding chairs.Next,to address the issue caused by the varying scales of the sliding chairs,we employ K-means++to optimize the priori selection of the initial anchor boxes.Finally,based on the images collected from real-world turnouts,the proposed method is verified and the results show that our method outperforms the basic YOLOv7 in the state identification of the sliding chairs with 4%improvements in terms of both mean Average Precision@0.5(mAP@0.5)and F1-score.
文摘Using a sample of Chinese family firms listed from 1999 to 2014, we investigate the relationship between non-family leadership and firm performance. We find that firms with a non-family member as board chair perform significantly worse than firms whose chair belongs to the family. Moreover, we show that the underperformance of nonfamily-chair firms is more pronounced when firms are under weaker outside monitoring and when the controlling families care less about family business longevity. The negative effect of a non-family chair is robust to a variety of endogeneity tests. We also dismiss alternative explanations other than concern for reputation. Overall, our empirical results suggest that the social norms regarding family reputation are important in shaping the controlling shareholders＇ expropriation incentives and firm performance.
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.
基金supported by the Natural Science Foundation of China (52102312,51672234,and 52072325)the Natural Science Foundation of Hunan Province of China (2021JJ40528)+2 种基金the China Postdoctoral Science Foundation (2020M682581)the Macao Young Scholars Program (AM2021011)the College Student Innovation and Entrepreneurship Training Program (S202210530051)。
文摘The development of insertion-type anodes is the key to designing“rocking chair”zinc-ion batteries.However,there is rare report on high mass loading anode with high performances.Here,{001}-oriented Bi OCl nanosheets with Sn doping are proposed as a promising insertion-type anode.The designs of cross-linked CNTs conductive network,{001}-oriented nanosheet,and Sn doping significantly enhance ion/electron transport,proved via experimental tests and theoretical calculations(density of states and diffusion barrier).The H^(+)/Zn^(2+)synergistic co-insertion mechanism is proved via ex situ XRD,Raman,XPS,and SEM tests.Accordingly,this optimized electrode delivers a high reversible capacity of 194 m A h g^(-1)at 0.1 A g^(-1)with a voltage of≈0.37 V and an impressive cyclability with 128 m A h g^(-1)over 2500 cycles at 1 A g^(-1).It also shows satisfactory performances at an ultrahigh mass loading of 10 mg cm^(-2).Moreover,the Sn-Bi OCl//MnO_(2)full cell displays a reversible capacity of 85 m A h g^(-1)at 0.2 A g^(-1)during cyclic test.
文摘For the past six decades,Uganda and China have enjoyed remarkable bilateral relations and Uganda being recently elected to chair G77+China mechanism is set to drive the relationship to even greater heights.That’s according to Uganda’s First Deputy Prime Minister Rebecca Kadaga,who made the remarks recently while speaking at an event to mark the 74th anniversary of the founding of the People’s Republic of China.In response,the charge d’affaires at the Chinese Embassy in Uganda,Fan Xuecheng,toasted the long-standing friendship between the peoples of China and Uganda.
文摘目的研究星状神经节阻滞对肩关节镜手术沙滩椅位脑血流动力学改变的影响。方法取择期行沙滩椅位肩关节镜手术患者40例,随机分为治疗组T组和对照组C组各20例,T组术前行超声引导下SGB,对比两组患者术中生命体征、BIS值、脑氧合饱和度(rSO_(2))、不同时段大脑中动脉血流频谱图像、术后7 d ULCA评分、MMSE评分、RBANS总分,将两组数据进行统计学处理分析。结果T组比C组患者术中生命体征变化波动较小,差异有统计学意义(P<0.05)。不同时段rSO_(2)基本保持在相同水平,差异无统计学意义(P>0.05);T组患者大脑中动脉血流流速比C组要低,但血管内径要大,根据公式得出T组患者在不同时间段血流量都要比C组同时段的多,比较差异有统计学意义(P<0.05)。两组术后7 d ULCA评分、MMSE评分、RBANS总分对比T组明显较高,差异有统计学意义(P<0.05)。结论对沙滩椅位行肩关节镜手术的患者术前实施星状神经阻滞术具有增加脑血供及脑保护作用且对患者术后关节功能恢复有良好的促进作用,有临床推广实用价值。
