BACKGROUND Early identification of severe/critical coronavirus disease 2019(COVID-19)is crucial for timely treatment and intervention.Chest computed tomography(CT)score has been shown to be a significant factor in the...BACKGROUND Early identification of severe/critical coronavirus disease 2019(COVID-19)is crucial for timely treatment and intervention.Chest computed tomography(CT)score has been shown to be a significant factor in the diagnosis and treatment of pneumonia,however,there is currently a lack of effective early warning systems for severe/critical COVID-19 based on dynamic CT evolution.AIM To develop a severe/critical COVID-19 prediction model using a combination of imaging scores,clinical features,and biomarker levels.METHODS This study used an improved scoring system to extract and describe the chest CT characteristics of COVID-19 patients.The study also took into consideration the general clinical indicators such as dyspnea,oxygen saturation,alternative lengthening of telomeres(ALT),and androgen suppression treatment(AST),which are commonly associated with severe/critical COVID-19 cases.The study employed lasso regression to evaluate and rank the significance of different disease characteristics.RESULTS The results showed that blood oxygen saturation,ALT,IL-6/IL-10,combined score,ground glass opacity score,age,crazy paving mode score,qsofa,AST,and overall lung involvement score were key factors in predicting severe/critical COVID-19 cases.The study established a COVID-19 severe/critical early warning system using various machine learning algorithms,including XGBClassifier,Logistic Regression,MLPClassifier,RandomForestClassifier,and AdaBoost Classifier.The study concluded that the prediction model based on the improved CT score and machine learning algorithms is a feasible method for early detection of severe/critical COVID-19 evolution.CONCLUSION The findings of this study suggest that a prediction model based on improved CT scores and machine learning algorithms is effective in detecting the early warning signals of severe/critical COVID-19.展开更多
We propose a low-cost and high-damage-threshold phase control system that employs a piezoelectric ceramic transducer modulator controlled by a stochastic parallel gradient descent algorithm. Efficient phase locking of...We propose a low-cost and high-damage-threshold phase control system that employs a piezoelectric ceramic transducer modulator controlled by a stochastic parallel gradient descent algorithm. Efficient phase locking of two fiber amplifiers is demonstrated. Experimental results show that energy encircled in the target pinhole is increased by a factor of 1.76 and the visibility of the fringe pattern is as high as 90% when the system is in close-loop. The phase control system has potential in phase locking of large-number and high-power fiber laser endeavors.展开更多
In a recent paper [Yan F L et al. Chin.Phys.Lett. 25(2008)1187], a quantum secret sharing the protocol between multiparty and multiparty with single photons and unitary transformations was presented. We analyze the ...In a recent paper [Yan F L et al. Chin.Phys.Lett. 25(2008)1187], a quantum secret sharing the protocol between multiparty and multiparty with single photons and unitary transformations was presented. We analyze the security of the protocol and find that a dishonest participant can eavesdrop the key by using a special attack. Finally, we give a description of this strategy and put forward an improved version of this protocol which can stand against this kind of attack.展开更多
The existing theory of decoy-state quantum cryptography assumes that the dark count rate is a constant, but in practice there exists fluctuation. We develop a new scheme of the decoy state, achieve a more practical ke...The existing theory of decoy-state quantum cryptography assumes that the dark count rate is a constant, but in practice there exists fluctuation. We develop a new scheme of the decoy state, achieve a more practical key generation rate in the presence of fluctuation of the dark count rate, and compare the result with the result of the decoy-state without fluctuation. It is found that the key generation rate and maximal secure distance will be decreased under the influence of the fluctuation of the dark count rate.展开更多
A thin TiO2 layer inserted in a phase change memory (PCM) cell to form a deep sub-micro bottom electrode (DBE) is proposed and its electro-thermal characteristics are investigated with the three-dimensional finite...A thin TiO2 layer inserted in a phase change memory (PCM) cell to form a deep sub-micro bottom electrode (DBE) is proposed and its electro-thermal characteristics are investigated with the three-dimensional finite element analysis. Compared with the conventional PCM cell with a SiN stop layer, the reset threshold current of the PCM cell with the TiO2 layer is reduced from 1.8 mA to 1.2 mA and the ratio of the amorphous resistance and crystalline resistive increases from 65 to 100. The optimum thickness of the TiO2 layer and the optimum height of DBE are 10nm and 200nm, respectively. Therefore, the PCM cell with the TiO2 layer can decrease the programming power consumption and increase heating efficiency. The TiO2 film is a better candidate for the SiN film in the PCM cell structure to prepare DBE and to reduce programming power in the reset operation.展开更多
We recently proposed a flexible quantum secure direct communication protocol [Chin. Phys. Lett. 23 (2006) 3152]. By analyzing its security in the perfect channel from the aspect of quantum information theory, we fin...We recently proposed a flexible quantum secure direct communication protocol [Chin. Phys. Lett. 23 (2006) 3152]. By analyzing its security in the perfect channel from the aspect of quantum information theory, we find that an eavesdropper is capable of stealing all the information without being detected. Two typical attacks are presented to illustrate this point. A solution to this loophole is also suggested and we show its powerfulness against the most general individual attack in the ideal case. We also discuss the security in the imperfect case when there is noise and loss.展开更多
基金Supported by National Natural Science Foundation of China,No.81900641the Research Funding of Peking University,BMU2021MX020 and BMU2022MX008。
文摘BACKGROUND Early identification of severe/critical coronavirus disease 2019(COVID-19)is crucial for timely treatment and intervention.Chest computed tomography(CT)score has been shown to be a significant factor in the diagnosis and treatment of pneumonia,however,there is currently a lack of effective early warning systems for severe/critical COVID-19 based on dynamic CT evolution.AIM To develop a severe/critical COVID-19 prediction model using a combination of imaging scores,clinical features,and biomarker levels.METHODS This study used an improved scoring system to extract and describe the chest CT characteristics of COVID-19 patients.The study also took into consideration the general clinical indicators such as dyspnea,oxygen saturation,alternative lengthening of telomeres(ALT),and androgen suppression treatment(AST),which are commonly associated with severe/critical COVID-19 cases.The study employed lasso regression to evaluate and rank the significance of different disease characteristics.RESULTS The results showed that blood oxygen saturation,ALT,IL-6/IL-10,combined score,ground glass opacity score,age,crazy paving mode score,qsofa,AST,and overall lung involvement score were key factors in predicting severe/critical COVID-19 cases.The study established a COVID-19 severe/critical early warning system using various machine learning algorithms,including XGBClassifier,Logistic Regression,MLPClassifier,RandomForestClassifier,and AdaBoost Classifier.The study concluded that the prediction model based on the improved CT score and machine learning algorithms is a feasible method for early detection of severe/critical COVID-19 evolution.CONCLUSION The findings of this study suggest that a prediction model based on improved CT scores and machine learning algorithms is effective in detecting the early warning signals of severe/critical COVID-19.
文摘We propose a low-cost and high-damage-threshold phase control system that employs a piezoelectric ceramic transducer modulator controlled by a stochastic parallel gradient descent algorithm. Efficient phase locking of two fiber amplifiers is demonstrated. Experimental results show that energy encircled in the target pinhole is increased by a factor of 1.76 and the visibility of the fringe pattern is as high as 90% when the system is in close-loop. The phase control system has potential in phase locking of large-number and high-power fiber laser endeavors.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60873191, 60903152 and 60821001, the SRFDP under Grant No 200800131016, Beijing Nova Program under Grant No 2008B51, Key Project of the Ministry of Education of China under Grant No 109014, China Postdoctoral Science Foundation under Grant No 20090450018, Fujian Provincial Natural Science Foundation under Grant No 2008J0013, and the Foundation of Fujian Education Bureau under Grant No 3A08044.
文摘In a recent paper [Yan F L et al. Chin.Phys.Lett. 25(2008)1187], a quantum secret sharing the protocol between multiparty and multiparty with single photons and unitary transformations was presented. We analyze the security of the protocol and find that a dishonest participant can eavesdrop the key by using a special attack. Finally, we give a description of this strategy and put forward an improved version of this protocol which can stand against this kind of attack.
基金Supported by the National Natural Science Foundation of China under Grant No 10504042.
文摘The existing theory of decoy-state quantum cryptography assumes that the dark count rate is a constant, but in practice there exists fluctuation. We develop a new scheme of the decoy state, achieve a more practical key generation rate in the presence of fluctuation of the dark count rate, and compare the result with the result of the decoy-state without fluctuation. It is found that the key generation rate and maximal secure distance will be decreased under the influence of the fluctuation of the dark count rate.
基金Supported by the National Basic Research Program of China (2007CB935400 and 2006CB302700), the National High Technology Research and Development Program of China (2008AA031402), Science and Technology Council of Shanghai (0752nm013, 07QA14065, 07SA08, 08DZ2200700, 08JC1421700), the National Nature Science Foundation of China (60776058), and Chinese Academy of Sciences (083YQA1001)
文摘A thin TiO2 layer inserted in a phase change memory (PCM) cell to form a deep sub-micro bottom electrode (DBE) is proposed and its electro-thermal characteristics are investigated with the three-dimensional finite element analysis. Compared with the conventional PCM cell with a SiN stop layer, the reset threshold current of the PCM cell with the TiO2 layer is reduced from 1.8 mA to 1.2 mA and the ratio of the amorphous resistance and crystalline resistive increases from 65 to 100. The optimum thickness of the TiO2 layer and the optimum height of DBE are 10nm and 200nm, respectively. Therefore, the PCM cell with the TiO2 layer can decrease the programming power consumption and increase heating efficiency. The TiO2 film is a better candidate for the SiN film in the PCM cell structure to prepare DBE and to reduce programming power in the reset operation.
文摘We recently proposed a flexible quantum secure direct communication protocol [Chin. Phys. Lett. 23 (2006) 3152]. By analyzing its security in the perfect channel from the aspect of quantum information theory, we find that an eavesdropper is capable of stealing all the information without being detected. Two typical attacks are presented to illustrate this point. A solution to this loophole is also suggested and we show its powerfulness against the most general individual attack in the ideal case. We also discuss the security in the imperfect case when there is noise and loss.