提出了一种应用于18 bit 20 MS/s无采保结构(SHA-Less)高精度流水线型(Pipeline)模数转换器(Analog-to-Digital Converter,ADC)的乘法数模单元(Multiplying Digital-to-Analog Converter,MDAC)。从减小电路动态、静态误差以及系统噪声...提出了一种应用于18 bit 20 MS/s无采保结构(SHA-Less)高精度流水线型(Pipeline)模数转换器(Analog-to-Digital Converter,ADC)的乘法数模单元(Multiplying Digital-to-Analog Converter,MDAC)。从减小电路动态、静态误差以及系统噪声的角度,介绍了高性能MDAC电路的设计方法。使用0.18μm CMOS工艺实现电路版图,并用Spectre和Calibre进行后仿验证。在室温条件下,输入5 MHz正弦波信号,采样频率为20 MHz,对设计的MDAC电路进行后端仿真并进行快速傅里叶变换(Fast Fourier Transform,FFT)处理,结果显示信噪比(Signal Noise Ratio,SNR)为87.32 d B,有效位数(Effective Number of Bits,ENOB)为13.97 bit,无杂散动态范围(Spurious Free Dynamic Range,SFDR)为90.53 d Bc,总谐波失真(Total Harmonic Distortion,THD)为-90.74 d B。展开更多
Objective:To investigate a new noninvasive diagnostic model for nonalcoholic fatty liver disease(NAFLD) based on features of tongue images.Methods:Healthy controls and volunteers confirmed to have NAFLD by liver ultra...Objective:To investigate a new noninvasive diagnostic model for nonalcoholic fatty liver disease(NAFLD) based on features of tongue images.Methods:Healthy controls and volunteers confirmed to have NAFLD by liver ultrasound were recruited from China-Japan Friendship Hospital between September 2018 and May 2019,then the anthropometric indexes and sampled tongue images were measured.The tongue images were labeled by features,based on a brief protocol,without knowing any other clinical data,after a series of corrections and data cleaning.The algorithm was trained on images using labels and several anthropometric indexes for inputs,utilizing machine learning technology.Finally,a logistic regression algorithm and a decision tree model were constructed as 2 diagnostic models for NAFLD.Results:A total of 720 subjects were enrolled in this study,including 432 patients with NAFLD and 288 healthy volunteers.Of them,482 were randomly allocated into the training set and 238 into the validation set.The diagnostic model based on logistic regression exhibited excellent performance:in validation set,it achieved an accuracy of 86.98%,sensitivity of 91.43%,and specificity of 80.61%;with an area under the curve(AUC) of 0.93 [95% confidence interval(CI) 0.68–0.98].The decision tree model achieved an accuracy of 81.09%,sensitivity of 91.43%,and specificity of 66.33%;with an AUC of 0.89(95% CI 0.66–0.92) in validation set.Conclusions:The features of tongue images were associated with NAFLD.Both the 2 diagnostic models,which would be convenient,noninvasive,lightweight,rapid,and inexpensive technical references for early screening,can accurately distinguish NAFLD and are worth further study.展开更多
We report herein an unprecedented N-heterocyclic carbene-catalyzed formal[3+3]annulation of ynals with N-Ts indolin-3-ones under the oxidation condition affording the functionalized pyrano[3,2-b]indol-2-ones.The alkyn...We report herein an unprecedented N-heterocyclic carbene-catalyzed formal[3+3]annulation of ynals with N-Ts indolin-3-ones under the oxidation condition affording the functionalized pyrano[3,2-b]indol-2-ones.The alkynyl acylazoliums via the combination of a carbene with ynals in the presence of oxidate proved to be the important intermediates for the success of this transformation.This method features a broad substrate scope and mild conditions,including axially chiral skeletons with suitable substitutions.展开更多
文摘提出了一种应用于18 bit 20 MS/s无采保结构(SHA-Less)高精度流水线型(Pipeline)模数转换器(Analog-to-Digital Converter,ADC)的乘法数模单元(Multiplying Digital-to-Analog Converter,MDAC)。从减小电路动态、静态误差以及系统噪声的角度,介绍了高性能MDAC电路的设计方法。使用0.18μm CMOS工艺实现电路版图,并用Spectre和Calibre进行后仿验证。在室温条件下,输入5 MHz正弦波信号,采样频率为20 MHz,对设计的MDAC电路进行后端仿真并进行快速傅里叶变换(Fast Fourier Transform,FFT)处理,结果显示信噪比(Signal Noise Ratio,SNR)为87.32 d B,有效位数(Effective Number of Bits,ENOB)为13.97 bit,无杂散动态范围(Spurious Free Dynamic Range,SFDR)为90.53 d Bc,总谐波失真(Total Harmonic Distortion,THD)为-90.74 d B。
基金Supported by the Innovation Project for Deep Integration of Artificial Intelligence and the Real Economy,the Ministry of Industry and Information Technology of the People’s Republic of China。
文摘Objective:To investigate a new noninvasive diagnostic model for nonalcoholic fatty liver disease(NAFLD) based on features of tongue images.Methods:Healthy controls and volunteers confirmed to have NAFLD by liver ultrasound were recruited from China-Japan Friendship Hospital between September 2018 and May 2019,then the anthropometric indexes and sampled tongue images were measured.The tongue images were labeled by features,based on a brief protocol,without knowing any other clinical data,after a series of corrections and data cleaning.The algorithm was trained on images using labels and several anthropometric indexes for inputs,utilizing machine learning technology.Finally,a logistic regression algorithm and a decision tree model were constructed as 2 diagnostic models for NAFLD.Results:A total of 720 subjects were enrolled in this study,including 432 patients with NAFLD and 288 healthy volunteers.Of them,482 were randomly allocated into the training set and 238 into the validation set.The diagnostic model based on logistic regression exhibited excellent performance:in validation set,it achieved an accuracy of 86.98%,sensitivity of 91.43%,and specificity of 80.61%;with an area under the curve(AUC) of 0.93 [95% confidence interval(CI) 0.68–0.98].The decision tree model achieved an accuracy of 81.09%,sensitivity of 91.43%,and specificity of 66.33%;with an AUC of 0.89(95% CI 0.66–0.92) in validation set.Conclusions:The features of tongue images were associated with NAFLD.Both the 2 diagnostic models,which would be convenient,noninvasive,lightweight,rapid,and inexpensive technical references for early screening,can accurately distinguish NAFLD and are worth further study.
基金We thank the financial support from the Program for Young Talents of Shaanxi Province(5113200043)the Fundamental Research Funds for the Central Universities.
文摘We report herein an unprecedented N-heterocyclic carbene-catalyzed formal[3+3]annulation of ynals with N-Ts indolin-3-ones under the oxidation condition affording the functionalized pyrano[3,2-b]indol-2-ones.The alkynyl acylazoliums via the combination of a carbene with ynals in the presence of oxidate proved to be the important intermediates for the success of this transformation.This method features a broad substrate scope and mild conditions,including axially chiral skeletons with suitable substitutions.
