The proposed DAC consists of a unit current-cell matrix for 8MSBs and a binary-weighted array for 4LSBs,trading-off between the precision,speed,and size of the chip.In order to ensure the linearity of the DAC,a double...The proposed DAC consists of a unit current-cell matrix for 8MSBs and a binary-weighted array for 4LSBs,trading-off between the precision,speed,and size of the chip.In order to ensure the linearity of the DAC,a double Centro symmetric current matrix is designed by the Q2 random walk strategy.To achieve better dynamic performance,a latch is added in front of the current switch to change the input signal,such as its optimal cross-point and voltage level.For a 12bit resolution,the converter reaches an update rate of 300MHz.展开更多
This paper presents a 2GS/s 10bit CMOS digital-to-analog converter （DAC） that consists of two unit current-cell matrixes for 6MSBs and 4LSBs, respectively, trading off between the precision and size of the chip. Cur...This paper presents a 2GS/s 10bit CMOS digital-to-analog converter （DAC） that consists of two unit current-cell matrixes for 6MSBs and 4LSBs, respectively, trading off between the precision and size of the chip. Current mode logic （CML） is used to ensure high speed,and a double centro-symmetric current matrix is designed by the Q^2 random walk strategy in order to ensure the linearity of the DAC. The DAC occupies 2.2mm × 2.2mm of die area and consumes 790mW with a single 3.3V power supply.展开更多
The manufacturing of spiral groove structure of two-dimensional valve(2D valve)feedback mechanism has shortcomings of both high cost and time-consuming.This paper presents a novel configuration of rotary electro-mecha...The manufacturing of spiral groove structure of two-dimensional valve(2D valve)feedback mechanism has shortcomings of both high cost and time-consuming.This paper presents a novel configuration of rotary electro-mechanical converter with negative feedback mechanism(REMC-NFM)in order to replace the feedback mechanism of spiral groove and thus reduce cost of valve manufacturing.In order to rapidly and quantitative evaluate the driving and feedback performance of the REMC-NFM,an analytical model taking leakage flux,edge effect and permeability nonlinearity into account is formulated based on the equivalent magnetic circuit approach.Then the model is properly simplified in order to obtain the optimal pitch angle.FEM simulation is used to study the influence of crucial parameters on the performance of REMC-NFM.A prototype of REMC-NFM is designed and machined,and an exclusive experimental platform is built.The torque-angle characteristics,torque-displacement characteristics,and magnetic flux density in the working air gap with different excitation currents are measured.The experimental results are in good agreement with the analytical and FEM simulated results,which verifies the correctness of the analytical model.For torque-angle characteristics,the overall torque increases with both current and rotation angle,which reaches about 0.48 N·m with 1.5 A and 1.5°.While for torque-displacement characteristics,the overall torque increases with current yet decrease with armature displacement due to the negative feedback mechanism,which is about 0.16 N·m with 1.5 A and 0.8 mm.Besides,experimental results of conventional torque motor are compared with counterparts of REMC-NFM in order to validate the simplified model.The research indicates that the REMC-NFM can be potentially used as the electro-mechanical converter for 2D valves in civil servo areas.展开更多
China is an important country in iron and steel industry.Power electronics converters are widely used.For the cold rolling mills of high speed,AC-DC-AC converters should be used.In the paper,the design and the control...China is an important country in iron and steel industry.Power electronics converters are widely used.For the cold rolling mills of high speed,AC-DC-AC converters should be used.In the paper,the design and the control system of the large power three-level AC - DC - AC converter with IGCTs is investigated,and a back-to-back large power three-level AC - DC - AC converter with IGCTs has been got. With a series experiments,the performance of the converter is examined.The experiment result indicates the converter reaches the design requirement and it shows excellent performance.The converter system has been put into use safely.It is estimated that the AC - DC - AC converter system will be used in the drive systems for rolling mills in the near future.展开更多
目的分析2型糖尿病患者25-羟维生素D[25(OH)D]水平,初步了解血清25(OH)D水平与2型糖尿病患者糖化血红蛋白(HbA1c)、胰岛功能等代谢指标的相关性。方法选择新乡市第一人民医院内分泌科2020年1月至2020年12月收治的459例2型糖尿病患者为...目的分析2型糖尿病患者25-羟维生素D[25(OH)D]水平,初步了解血清25(OH)D水平与2型糖尿病患者糖化血红蛋白(HbA1c)、胰岛功能等代谢指标的相关性。方法选择新乡市第一人民医院内分泌科2020年1月至2020年12月收治的459例2型糖尿病患者为研究对象。收集患者的临床资料,包括性别、年龄、血清25(OH)D、空腹胰岛素、C肽、HbA1c、空腹血糖、餐后血糖、尿微量白蛋白、尿白蛋白肌酐比值、血钙、血尿酸(UA)、三酰甘油(TG)、总胆固醇(TCH)、低密度脂蛋白(LDL)、高密度脂蛋白(HDL)等。根据血清25(OH)D水平将患者分为充足组[n=20,25(OH)D≥30μg·L^(-1)]、不足组[n=95,20μg·L^(-1)≤25(OH)D<30μg·L^(-1)]、缺乏组[n=231,10μg·L^(-1)≤25(OH)D<20μg·L^(-1)]、严重缺乏组[n=113,25(OH)D<10μg·L^(-1)]。比较4组患者各代谢指标的差异,采用Pearson相关分析25(OH)D与各代谢指标的相关性。结果2型糖尿病患者血清25(OH)D水平为3.00~46.59(15.75±0.35)μg·L^(-1),男性患者的血清25(OH)D水平显著高于女性患者(P<0.05)。2型糖尿病患者25(OH)D缺乏的患病率为74.9%(344/459),25(OH)D缺乏主要发生在1、2、3、4、11、12月份。不足组、缺乏组和严重缺乏组患者HbA1c显著高于充足组(P<0.05),缺乏组和严重缺乏组患者HbA1c显著高于不足组(P<0.05);缺乏组和严重缺乏组患者HbA1c比较差异无统计学意义(P>0.05)。充足组与不足组、缺乏组与严重缺乏组患者空腹血糖比较差异无统计学意义(P>0.05);缺乏组和严重缺乏组患者空腹血糖显著高于充足组、不足组(P<0.05)。充足组、不足组、缺乏组患者空腹胰岛素、尿微量白蛋白、日尿白蛋白总量、尿白蛋白肌酐比值比较差异无统计学意义(P>0.05);严重缺乏组患者空腹胰岛素显著低于充足组、不足组和缺乏组,尿微量白蛋白、日尿白蛋白总量、尿白蛋白肌酐比值显著高于充足组、不足组和缺乏组(P<0.05)。4组患者的稳态模型评估的胰岛素抵抗指数(HOMA-IR)、血清白蛋白、血肌酐、餐后1 h血糖、餐后2 h血糖、餐后3 h血糖、空腹C肽、餐后1 h C肽、餐后2 h C肽、餐后3 h C肽、TG、TCH、LDL、HDL、血UA、血钙比较差异均无统计学意义(P>0.05)。Pearson相关性分析结果显示,2型糖尿病患者血清25(OH)D水平与HbA1c、尿微量白蛋白、尿白蛋白肌酐比值呈负相关(r=-0.093、-0.166、-0.157,P<0.05),与空腹胰岛素呈正相关(r=0.089,P<0.05)。2型糖尿病患者血清25(OH)D水平与空腹血糖、HOMA-IR、血清白蛋白、血肌酐、餐后1 h血糖、餐后2 h血糖、餐后3 h血糖、空腹C肽、餐后1 h C肽、餐后2 h C肽、餐后3 h C肽、TG、TCH、LDL、HDL、血UA、血钙等无相关性(P>0.05)。结论2型糖尿病患者25(OH)D缺乏与不足普遍存在,女性患者缺乏更明显。2型糖尿病患者25(OH)D水平与空腹胰岛素呈正相关,与HbA1c、尿微量白蛋白、尿白蛋白肌酐比值呈负相关,25(OH)D缺乏的2型糖尿病患者主要分布在1、2、3、4、11、12月份。展开更多
A 16 bit stereo audio novel stability fifth-order ∑△ A/D converter that consists of switched capacitor ∑△ modulators, a decimation filter, and a bandgap circuit is proposed. A method for the stabilization of a hig...A 16 bit stereo audio novel stability fifth-order ∑△ A/D converter that consists of switched capacitor ∑△ modulators, a decimation filter, and a bandgap circuit is proposed. A method for the stabilization of a high order single stage ∑△ modulator is also proposed. A new multistage comb filter is used for the front end decimation filter. The ∑△ A/D converter achieves a peak SNR of 96dB and a dynamic range of 96dB. The ADC was implemented in 0. 5μm 5V CMOS technology. The chip die area occupies only 4. 1mm × 2.4mm and dissipates 90mW.展开更多
文摘The proposed DAC consists of a unit current-cell matrix for 8MSBs and a binary-weighted array for 4LSBs,trading-off between the precision,speed,and size of the chip.In order to ensure the linearity of the DAC,a double Centro symmetric current matrix is designed by the Q2 random walk strategy.To achieve better dynamic performance,a latch is added in front of the current switch to change the input signal,such as its optimal cross-point and voltage level.For a 12bit resolution,the converter reaches an update rate of 300MHz.
文摘This paper presents a 2GS/s 10bit CMOS digital-to-analog converter （DAC） that consists of two unit current-cell matrixes for 6MSBs and 4LSBs, respectively, trading off between the precision and size of the chip. Current mode logic （CML） is used to ensure high speed,and a double centro-symmetric current matrix is designed by the Q^2 random walk strategy in order to ensure the linearity of the DAC. The DAC occupies 2.2mm × 2.2mm of die area and consumes 790mW with a single 3.3V power supply.
基金National Natural Science Foundation of China(Grant Nos.51975524,51405443)National Key Research and Development Program of China(Grant No.2019YFB2005200).
文摘The manufacturing of spiral groove structure of two-dimensional valve(2D valve)feedback mechanism has shortcomings of both high cost and time-consuming.This paper presents a novel configuration of rotary electro-mechanical converter with negative feedback mechanism(REMC-NFM)in order to replace the feedback mechanism of spiral groove and thus reduce cost of valve manufacturing.In order to rapidly and quantitative evaluate the driving and feedback performance of the REMC-NFM,an analytical model taking leakage flux,edge effect and permeability nonlinearity into account is formulated based on the equivalent magnetic circuit approach.Then the model is properly simplified in order to obtain the optimal pitch angle.FEM simulation is used to study the influence of crucial parameters on the performance of REMC-NFM.A prototype of REMC-NFM is designed and machined,and an exclusive experimental platform is built.The torque-angle characteristics,torque-displacement characteristics,and magnetic flux density in the working air gap with different excitation currents are measured.The experimental results are in good agreement with the analytical and FEM simulated results,which verifies the correctness of the analytical model.For torque-angle characteristics,the overall torque increases with both current and rotation angle,which reaches about 0.48 N·m with 1.5 A and 1.5°.While for torque-displacement characteristics,the overall torque increases with current yet decrease with armature displacement due to the negative feedback mechanism,which is about 0.16 N·m with 1.5 A and 0.8 mm.Besides,experimental results of conventional torque motor are compared with counterparts of REMC-NFM in order to validate the simplified model.The research indicates that the REMC-NFM can be potentially used as the electro-mechanical converter for 2D valves in civil servo areas.
文摘China is an important country in iron and steel industry.Power electronics converters are widely used.For the cold rolling mills of high speed,AC-DC-AC converters should be used.In the paper,the design and the control system of the large power three-level AC - DC - AC converter with IGCTs is investigated,and a back-to-back large power three-level AC - DC - AC converter with IGCTs has been got. With a series experiments,the performance of the converter is examined.The experiment result indicates the converter reaches the design requirement and it shows excellent performance.The converter system has been put into use safely.It is estimated that the AC - DC - AC converter system will be used in the drive systems for rolling mills in the near future.
文摘目的分析2型糖尿病患者25-羟维生素D[25(OH)D]水平,初步了解血清25(OH)D水平与2型糖尿病患者糖化血红蛋白(HbA1c)、胰岛功能等代谢指标的相关性。方法选择新乡市第一人民医院内分泌科2020年1月至2020年12月收治的459例2型糖尿病患者为研究对象。收集患者的临床资料,包括性别、年龄、血清25(OH)D、空腹胰岛素、C肽、HbA1c、空腹血糖、餐后血糖、尿微量白蛋白、尿白蛋白肌酐比值、血钙、血尿酸(UA)、三酰甘油(TG)、总胆固醇(TCH)、低密度脂蛋白(LDL)、高密度脂蛋白(HDL)等。根据血清25(OH)D水平将患者分为充足组[n=20,25(OH)D≥30μg·L^(-1)]、不足组[n=95,20μg·L^(-1)≤25(OH)D<30μg·L^(-1)]、缺乏组[n=231,10μg·L^(-1)≤25(OH)D<20μg·L^(-1)]、严重缺乏组[n=113,25(OH)D<10μg·L^(-1)]。比较4组患者各代谢指标的差异,采用Pearson相关分析25(OH)D与各代谢指标的相关性。结果2型糖尿病患者血清25(OH)D水平为3.00~46.59(15.75±0.35)μg·L^(-1),男性患者的血清25(OH)D水平显著高于女性患者(P<0.05)。2型糖尿病患者25(OH)D缺乏的患病率为74.9%(344/459),25(OH)D缺乏主要发生在1、2、3、4、11、12月份。不足组、缺乏组和严重缺乏组患者HbA1c显著高于充足组(P<0.05),缺乏组和严重缺乏组患者HbA1c显著高于不足组(P<0.05);缺乏组和严重缺乏组患者HbA1c比较差异无统计学意义(P>0.05)。充足组与不足组、缺乏组与严重缺乏组患者空腹血糖比较差异无统计学意义(P>0.05);缺乏组和严重缺乏组患者空腹血糖显著高于充足组、不足组(P<0.05)。充足组、不足组、缺乏组患者空腹胰岛素、尿微量白蛋白、日尿白蛋白总量、尿白蛋白肌酐比值比较差异无统计学意义(P>0.05);严重缺乏组患者空腹胰岛素显著低于充足组、不足组和缺乏组,尿微量白蛋白、日尿白蛋白总量、尿白蛋白肌酐比值显著高于充足组、不足组和缺乏组(P<0.05)。4组患者的稳态模型评估的胰岛素抵抗指数(HOMA-IR)、血清白蛋白、血肌酐、餐后1 h血糖、餐后2 h血糖、餐后3 h血糖、空腹C肽、餐后1 h C肽、餐后2 h C肽、餐后3 h C肽、TG、TCH、LDL、HDL、血UA、血钙比较差异均无统计学意义(P>0.05)。Pearson相关性分析结果显示,2型糖尿病患者血清25(OH)D水平与HbA1c、尿微量白蛋白、尿白蛋白肌酐比值呈负相关(r=-0.093、-0.166、-0.157,P<0.05),与空腹胰岛素呈正相关(r=0.089,P<0.05)。2型糖尿病患者血清25(OH)D水平与空腹血糖、HOMA-IR、血清白蛋白、血肌酐、餐后1 h血糖、餐后2 h血糖、餐后3 h血糖、空腹C肽、餐后1 h C肽、餐后2 h C肽、餐后3 h C肽、TG、TCH、LDL、HDL、血UA、血钙等无相关性(P>0.05)。结论2型糖尿病患者25(OH)D缺乏与不足普遍存在,女性患者缺乏更明显。2型糖尿病患者25(OH)D水平与空腹胰岛素呈正相关,与HbA1c、尿微量白蛋白、尿白蛋白肌酐比值呈负相关,25(OH)D缺乏的2型糖尿病患者主要分布在1、2、3、4、11、12月份。
文摘A 16 bit stereo audio novel stability fifth-order ∑△ A/D converter that consists of switched capacitor ∑△ modulators, a decimation filter, and a bandgap circuit is proposed. A method for the stabilization of a high order single stage ∑△ modulator is also proposed. A new multistage comb filter is used for the front end decimation filter. The ∑△ A/D converter achieves a peak SNR of 96dB and a dynamic range of 96dB. The ADC was implemented in 0. 5μm 5V CMOS technology. The chip die area occupies only 4. 1mm × 2.4mm and dissipates 90mW.
