A new method for the determination of utratrace silver(I) by near field thermal lens spectrometry has been developed. This method is based on the silver(I) catalyzed discoloring reaction of bromocresol green oxidized...A new method for the determination of utratrace silver(I) by near field thermal lens spectrometry has been developed. This method is based on the silver(I) catalyzed discoloring reaction of bromocresol green oxidized by sodium persulphate in the presence of a, a-bipy as activator and Triton X-100 as sensitizer. The linear range of this method is 0~1.6 ng穖L-1 of silver. The detection limit is 2?0-2 ng穖L-1. The method has been applied to the determination of silver in lead power and photographic paper with satisfactory results.展开更多
Intertrochanteric fractures have become a severe public health problem in elderly patients.Proximal femoral nail anti-rotation(PFNA)is a commonly used intramedullary fixation device for unstable intertrochanteric frac...Intertrochanteric fractures have become a severe public health problem in elderly patients.Proximal femoral nail anti-rotation(PFNA)is a commonly used intramedullary fixation device for unstable intertrochanteric fractures.Pelvic perforation by cephalic screw is a rare complication.We reported an 84-year-old female who fell at home and sustained an intertrochanteric fracture.The patient underwent surgery with PFNA as the intramedullary fixation device.Routine postoperative examination revealed medial migration of the helical blade that eventually caused pelvic perforation.We performed a cemented total hip arthroplasty as the savage procedure.At the latest follow-up of 12 months after total hip arthroplasty,the patient had no pain or loosening of the prosthesis in the left hip.Pelvic perforation should be considered when choosing PFNA as the intramedullary fixation device,especially in patients with severe osteoporosis wherein the helical blade can be easily inserted during the operation.The lack of devices to avoid oversliding of the helical blade in PFNA is an unreported cause of this complication and should be considered in such cases.展开更多
Traditionally,the friction force has been the benchmark for quantifying energy dissipation in frictional phenomena.In this study,we introduce an atomic chain friction model that illuminates the conversion of kinetic e...Traditionally,the friction force has been the benchmark for quantifying energy dissipation in frictional phenomena.In this study,we introduce an atomic chain friction model that illuminates the conversion of kinetic energy into potential energy through interfacial forces.The energy dissipation process is characterized by the release of partial potential energy in the form of phonons,quantifiable by a frictional damping coefficient.We have determined that this damping coefficient is significantly influenced by the intrinsic dynamic properties of the friction system.To expand on this foundation,we formulate an advanced phononic friction model that accurately predicts the friction forces measured using an atomic force microscope(AFM).Our model reveals that energy dissipation is caused by vibrations occurring both parallel and perpendicular to the sliding motion.These findings profoundly enhance our understanding of the basic mechanics of friction and open new avenues for innovative strategies for the active management and reduction of energy dissipation in diverse mechanical systems.展开更多
With the aim of guaranteeing the interests and health of tourists,this study comprehensively evaluates the suitability of the environment in different cities in China for tourism by considering the impacts of climate,...With the aim of guaranteeing the interests and health of tourists,this study comprehensively evaluates the suitability of the environment in different cities in China for tourism by considering the impacts of climate,vegetation and environmental factors on health.The Universal Thermal Climate Index(UTCI),total precipitation(PREC),Vegetation Leaf Area Index(LAI),concentration of particulate matter with a diameter of less than 2.5μm(PM2.5),and the downward UV radiation at the surface(UVB)are used as indices.In addition,the Delphi–AHP–TOPSIS algorithm is introduced and is used for the comprehensive evaluation of the environmental suitability of 684 cities in China for tourism in 2019.It is found that Chinese cities vary greatly in terms of the suitability of their environments for tourism.Among the factors that affect the environmental suitability,the LAI is important,with an increase in the LAI generally being advantageous.In contrast,an increase in the PM2.5 concentration is a key factor that limits the environmental suitability of an area.Thus,urban landscaping and control of the atmospheric quality are essential and effective ways of improving the suitability of the environment of cities in China for tourists.展开更多
文摘A new method for the determination of utratrace silver(I) by near field thermal lens spectrometry has been developed. This method is based on the silver(I) catalyzed discoloring reaction of bromocresol green oxidized by sodium persulphate in the presence of a, a-bipy as activator and Triton X-100 as sensitizer. The linear range of this method is 0~1.6 ng穖L-1 of silver. The detection limit is 2?0-2 ng穖L-1. The method has been applied to the determination of silver in lead power and photographic paper with satisfactory results.
基金National Key R&D Program of China,2018YFF0301103,The funding body will support the publication fees without affecting the diagnosis and treatment of the patient and the writing of the manuscript.
文摘Intertrochanteric fractures have become a severe public health problem in elderly patients.Proximal femoral nail anti-rotation(PFNA)is a commonly used intramedullary fixation device for unstable intertrochanteric fractures.Pelvic perforation by cephalic screw is a rare complication.We reported an 84-year-old female who fell at home and sustained an intertrochanteric fracture.The patient underwent surgery with PFNA as the intramedullary fixation device.Routine postoperative examination revealed medial migration of the helical blade that eventually caused pelvic perforation.We performed a cemented total hip arthroplasty as the savage procedure.At the latest follow-up of 12 months after total hip arthroplasty,the patient had no pain or loosening of the prosthesis in the left hip.Pelvic perforation should be considered when choosing PFNA as the intramedullary fixation device,especially in patients with severe osteoporosis wherein the helical blade can be easily inserted during the operation.The lack of devices to avoid oversliding of the helical blade in PFNA is an unreported cause of this complication and should be considered in such cases.
基金the National Natural Science Foundation of China(Nos.52127811,52035003,51575104,51705074,52175161,and T2321002)the Natural Science Foundation of Jiangsu Province(No.BK20222005)for financial supportthe Southeast University“Zhongying Young Scholars”Project.
文摘Traditionally,the friction force has been the benchmark for quantifying energy dissipation in frictional phenomena.In this study,we introduce an atomic chain friction model that illuminates the conversion of kinetic energy into potential energy through interfacial forces.The energy dissipation process is characterized by the release of partial potential energy in the form of phonons,quantifiable by a frictional damping coefficient.We have determined that this damping coefficient is significantly influenced by the intrinsic dynamic properties of the friction system.To expand on this foundation,we formulate an advanced phononic friction model that accurately predicts the friction forces measured using an atomic force microscope(AFM).Our model reveals that energy dissipation is caused by vibrations occurring both parallel and perpendicular to the sliding motion.These findings profoundly enhance our understanding of the basic mechanics of friction and open new avenues for innovative strategies for the active management and reduction of energy dissipation in diverse mechanical systems.
基金funded by Beijing Social Science Fund[grant number 20GLC064]It was also supported by a grant from the State Key Laboratory of Resources and Environmental Information System,CAS+5 种基金the National Natural Science Foundation of China[grant number 71673015/G031031]the National Natural Science Foundation of China[grant number 42071199]Research on coupling mechanism and collaborative optimization of tourism industry evolution and ecological security in ice and snow tourism destinationsthe 2020 National Social Science Fund Art Major Project of China(the International Comparative Study on National Cultural Park Policy)[grant number 20ZD02]Beijing International Studies University’s 2020 Youth Academic Talents Program(Research on hourly tourism suitability prediction of tourism cities based on big data and remote sensing technology),the 2020 New Teaching Staff’s Scientific Research Sailing Plan(Study on dynamic assessment of haze population exposure risk in tourism cities)[grant number KYQH20A011]National Social Science Fund Project:Research on the coordination mechanism between heritage protection and tourism utilization of National Cultural Park[grant number 21bh157].
文摘With the aim of guaranteeing the interests and health of tourists,this study comprehensively evaluates the suitability of the environment in different cities in China for tourism by considering the impacts of climate,vegetation and environmental factors on health.The Universal Thermal Climate Index(UTCI),total precipitation(PREC),Vegetation Leaf Area Index(LAI),concentration of particulate matter with a diameter of less than 2.5μm(PM2.5),and the downward UV radiation at the surface(UVB)are used as indices.In addition,the Delphi–AHP–TOPSIS algorithm is introduced and is used for the comprehensive evaluation of the environmental suitability of 684 cities in China for tourism in 2019.It is found that Chinese cities vary greatly in terms of the suitability of their environments for tourism.Among the factors that affect the environmental suitability,the LAI is important,with an increase in the LAI generally being advantageous.In contrast,an increase in the PM2.5 concentration is a key factor that limits the environmental suitability of an area.Thus,urban landscaping and control of the atmospheric quality are essential and effective ways of improving the suitability of the environment of cities in China for tourists.
