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
目的探讨金匮肾气丸联合维生素D钙片治疗2型糖尿病性骨质疏松症(T2DOP)的临床疗效,以及对患者血清骨转换标志物、白细胞介素-1β(IL-1β)、基质金属蛋白酶-9(MMP-9)、超氧化物歧化酶(SOD)水平的影响。方法选择该院2021年1月至2022年10...目的探讨金匮肾气丸联合维生素D钙片治疗2型糖尿病性骨质疏松症(T2DOP)的临床疗效,以及对患者血清骨转换标志物、白细胞介素-1β(IL-1β)、基质金属蛋白酶-9(MMP-9)、超氧化物歧化酶(SOD)水平的影响。方法选择该院2021年1月至2022年10月收治的84例T2DOP患者作为研究对象,按随机数字表法将患者分为观察组(42例)和对照组(42例)。观察组采用金匮肾气丸联合维生素D钙片治疗,对照组单用维生素D钙片治疗,治疗24周后比较两组临床疗效。治疗前后检测两组患者第1~4腰椎(L 1~4)、股骨颈的骨密度(BMD),并对两组患者进行疼痛视觉模拟量表(VAS)评分。治疗前后检测两组患者的糖代谢指标[空腹血糖(FPG)、餐后2 h血糖(2 h PG)、糖化血红蛋白(HbA1c)]、血清骨转换标志物{25羟基维生素D[25(OH)D]、β-胶原特殊序列(β-Crosslaps)、总Ⅰ型胶原氨基端延长肽(Total-P1NP)、骨钙素N端中分子片段(N-MID)}以及IL-1β、MMP-9、SOD水平。统计两组不良反应发生情况。结果观察组总有效率为95.24%,明显高于对照组的76.19%(P<0.05)。治疗后,两组L 1~4 BMD以及血清25(OH)D、Total-P1NP、N-MID、SOD水平均高于治疗前(P<0.05),VAS评分、FPG、2 h PG、HbA1c以及血清β-Crosslaps、IL-1β、MMP-9水平均低于治疗前(P<0.05)。治疗后,观察组L 1~4 BMD以及血清25(OH)D、Total-P1NP、N-MID、SOD水平均高于对照组(P<0.05),VAS评分、FPG、2 h PG、HbA1c以及血清β-Crosslaps、IL-1β、MMP-9水平均低于对照组(P<0.05)。两组不良反应总发生率比较,差异无统计学意义(P>0.05)。结论金匮肾气丸联合维生素D钙片治疗T2DOP能有效调节患者血清骨转换标志物、IL-1β、MMP-9、SOD水平,改善糖代谢与骨代谢,提高临床疗效。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
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.
文摘目的探讨金匮肾气丸联合维生素D钙片治疗2型糖尿病性骨质疏松症(T2DOP)的临床疗效,以及对患者血清骨转换标志物、白细胞介素-1β(IL-1β)、基质金属蛋白酶-9(MMP-9)、超氧化物歧化酶(SOD)水平的影响。方法选择该院2021年1月至2022年10月收治的84例T2DOP患者作为研究对象,按随机数字表法将患者分为观察组(42例)和对照组(42例)。观察组采用金匮肾气丸联合维生素D钙片治疗,对照组单用维生素D钙片治疗,治疗24周后比较两组临床疗效。治疗前后检测两组患者第1~4腰椎(L 1~4)、股骨颈的骨密度(BMD),并对两组患者进行疼痛视觉模拟量表(VAS)评分。治疗前后检测两组患者的糖代谢指标[空腹血糖(FPG)、餐后2 h血糖(2 h PG)、糖化血红蛋白(HbA1c)]、血清骨转换标志物{25羟基维生素D[25(OH)D]、β-胶原特殊序列(β-Crosslaps)、总Ⅰ型胶原氨基端延长肽(Total-P1NP)、骨钙素N端中分子片段(N-MID)}以及IL-1β、MMP-9、SOD水平。统计两组不良反应发生情况。结果观察组总有效率为95.24%,明显高于对照组的76.19%(P<0.05)。治疗后,两组L 1~4 BMD以及血清25(OH)D、Total-P1NP、N-MID、SOD水平均高于治疗前(P<0.05),VAS评分、FPG、2 h PG、HbA1c以及血清β-Crosslaps、IL-1β、MMP-9水平均低于治疗前(P<0.05)。治疗后,观察组L 1~4 BMD以及血清25(OH)D、Total-P1NP、N-MID、SOD水平均高于对照组(P<0.05),VAS评分、FPG、2 h PG、HbA1c以及血清β-Crosslaps、IL-1β、MMP-9水平均低于对照组(P<0.05)。两组不良反应总发生率比较,差异无统计学意义(P>0.05)。结论金匮肾气丸联合维生素D钙片治疗T2DOP能有效调节患者血清骨转换标志物、IL-1β、MMP-9、SOD水平,改善糖代谢与骨代谢,提高临床疗效。
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.
