In this paper, we investigate the entanglement dynamics of a two-qubit entangled state coupled with its noisy envi- ronment, and plan to utilize weak measurement and quantum reversal measurement to study the entanglem...In this paper, we investigate the entanglement dynamics of a two-qubit entangled state coupled with its noisy envi- ronment, and plan to utilize weak measurement and quantum reversal measurement to study the entanglement dynamics under different decoherence channels in noninertial frames. Through the calculations and analyses, it is shown that the weak measurement can prevent entanglement from coupling to the amplitude damping channel, while the system is under the phase damping and flip channels. This protection protocol cannot prevent entanglement but will accelerate the death of entanglement. In addition, if the system is in the noninertial reference frame, then the effect of weak measurement will be weakened for the amplitude damping channel. Nevertheless, for other decoherence channels, the Unruh effect does not affect the quantum weak measurement, the only exception is that the maximum value of entanglement is reduced to √2/2 of the original value in the inertial frames.展开更多
An active queue management（AQM） algorithm called MCHOKeM is presented,which is borrowed from CHOKeW that draws multi-packets at random from the buffer,the multi-packets are compared with an arriving packet and aband...An active queue management（AQM） algorithm called MCHOKeM is presented,which is borrowed from CHOKeW that draws multi-packets at random from the buffer,the multi-packets are compared with an arriving packet and abandoned if they are from the same flow.But MCHOKeM uses multiple virtual queues for different priority packets and enhances the drawing function by adjusting the maximum number of draws based on the current status of virtual queue length.The number of parameters that MCHOKeM needs to maintain is determined by the number of priority levels being supported by the router,which usually has a small limited value.In order to explain the features of MCHOKeM,an analytical model is used.A series of simulation tests to evaluate the performance are given.展开更多
Introduction:The effective dose caused by the external exposure of medical radiation workers has dramatically declined in China.By contrast,less attention has been given to internal exposure to radiation.This study ai...Introduction:The effective dose caused by the external exposure of medical radiation workers has dramatically declined in China.By contrast,less attention has been given to internal exposure to radiation.This study aimed to describe the national monitoring of the internal exposure of Chinese nuclear medicine(NM)workers from 2021 to 2023.These findings provide essential baseline data for enhancing radiation protection protocols in NM facilities and optimizing national internal exposure monitoring.Methods:All the non-military hospitals in China with an NM program were investigated.Portable gamma spectrometers were used to measure the ^(131)I activities of the thyroid of staff members at ^(131)I treatment sites.Results:A total of 998 hospitals in China had an NM program in 2023.Detectable rate(measurements above minimum detectable activity)decreased from 26.2%in 2021 to 20.1%in 2023.The proportion of measurements exceeding 1.0×10^(2) Bq decreased from 12.8%in 2021 to 10.0%in 2023.The detectable rate varied with job categories(P=0.001),with the detectable rate of cleaners being the highest.Conclusions:In China,^(131)I was detected in the thyroid of about one-fifth of the subjects working at radioiodine treatment sites.Detectable rate exhibited a slow downward trend in recent years.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11074002 and 61275119)the Doctoral Science Foundation of the Ministry of Education of China (Grant No.20103401110003)the Natural Science Research Project of the Education Department of Anhui Province,China (Grant Nos.KJ2013A205,KJ2011ZD07,and KJ2012Z309)
文摘In this paper, we investigate the entanglement dynamics of a two-qubit entangled state coupled with its noisy envi- ronment, and plan to utilize weak measurement and quantum reversal measurement to study the entanglement dynamics under different decoherence channels in noninertial frames. Through the calculations and analyses, it is shown that the weak measurement can prevent entanglement from coupling to the amplitude damping channel, while the system is under the phase damping and flip channels. This protection protocol cannot prevent entanglement but will accelerate the death of entanglement. In addition, if the system is in the noninertial reference frame, then the effect of weak measurement will be weakened for the amplitude damping channel. Nevertheless, for other decoherence channels, the Unruh effect does not affect the quantum weak measurement, the only exception is that the maximum value of entanglement is reduced to √2/2 of the original value in the inertial frames.
基金supported by the Beijing Natural Science Foundation(4102050)USFC-KOSEF Joint Research Project of China and Korea(60811140343)
文摘An active queue management（AQM） algorithm called MCHOKeM is presented,which is borrowed from CHOKeW that draws multi-packets at random from the buffer,the multi-packets are compared with an arriving packet and abandoned if they are from the same flow.But MCHOKeM uses multiple virtual queues for different priority packets and enhances the drawing function by adjusting the maximum number of draws based on the current status of virtual queue length.The number of parameters that MCHOKeM needs to maintain is determined by the number of priority levels being supported by the router,which usually has a small limited value.In order to explain the features of MCHOKeM,an analytical model is used.A series of simulation tests to evaluate the performance are given.
文摘Introduction:The effective dose caused by the external exposure of medical radiation workers has dramatically declined in China.By contrast,less attention has been given to internal exposure to radiation.This study aimed to describe the national monitoring of the internal exposure of Chinese nuclear medicine(NM)workers from 2021 to 2023.These findings provide essential baseline data for enhancing radiation protection protocols in NM facilities and optimizing national internal exposure monitoring.Methods:All the non-military hospitals in China with an NM program were investigated.Portable gamma spectrometers were used to measure the ^(131)I activities of the thyroid of staff members at ^(131)I treatment sites.Results:A total of 998 hospitals in China had an NM program in 2023.Detectable rate(measurements above minimum detectable activity)decreased from 26.2%in 2021 to 20.1%in 2023.The proportion of measurements exceeding 1.0×10^(2) Bq decreased from 12.8%in 2021 to 10.0%in 2023.The detectable rate varied with job categories(P=0.001),with the detectable rate of cleaners being the highest.Conclusions:In China,^(131)I was detected in the thyroid of about one-fifth of the subjects working at radioiodine treatment sites.Detectable rate exhibited a slow downward trend in recent years.
