A low-temperature superconducting quantum interference device(low-Tc SQUID)can improve the depth of exploration.However,a low-Tc SQUID may lose its lock owing to oscillations in the current or the occurrence of spikes...A low-temperature superconducting quantum interference device(low-Tc SQUID)can improve the depth of exploration.However,a low-Tc SQUID may lose its lock owing to oscillations in the current or the occurrence of spikes when the transmitter is switched off.If a low-Tc SQUID loses its lock,it becomes impossible for the low-Tc SQUID TEM system to function normally and stably for a long period of time.This hinders the practical use of the system.In field experiments,the transmitting current is accurately measured,the voltage overshoot and current spike data are recorded,and the gradient of the primary magnetic field at the center of the transmitting loop is calculated.After analyzing the results of field experiments,it was found that when the gradient of the primary magnetic field far exceeds the slew rate of a low-Tc SQUID,the low-Tc SQUID loses its lock.Based on the mechanisms of the transmitting oscillation,an RC serial and multi-parallel capacity snubber circuit used to suppress such oscillation is proposed.The results of simulation and field experiments show that,when using a 100 m×100 m transmitting loop,the gradient of the primary magnetic field is suppressed from 101.4 to 2.4 mT/s with a transmitting current of 40 A,and from 29.6 to 1.4 mT/s with a transmitting current of 20 A.Therefore,it can be concluded that the gradient of the primary magnetic field is below the slew rate of a low-Tc SQUID after adopting the proposed RC serial and multi-parallel capacity snubber circuit.In conclusion,the technique proposed in this paper solves the problem of a lost lock of a low-Tc SQUID,ensuring that the low-Tc SQUID TEM system functions stably for a long period of time,and providing technical assurance for ground TEM exploration at an additional depth.展开更多
为了将绝热CMOS电路嵌入到传统电路系统中替代耗能较大的部件,本文研究并设计绝热CMOS电路和传统CMOS电路两者之间的接口电路:传统CMOS到绝热CMOS(Traditional CMOS to Adiabatic CMOS,TC/AC)的接口电路、绝热CMOS到传统CMOS(Adiabatic ...为了将绝热CMOS电路嵌入到传统电路系统中替代耗能较大的部件,本文研究并设计绝热CMOS电路和传统CMOS电路两者之间的接口电路:传统CMOS到绝热CMOS(Traditional CMOS to Adiabatic CMOS,TC/AC)的接口电路、绝热CMOS到传统CMOS(Adiabatic CMOS to Traditional CMOS,AC/TC)的接口电路。这样传统CMOS电路可以通过TC/AC接口电路来驱动绝热CMOS电路,绝热CMOS电路可以通过AC/TC接口电路来驱动传统CMOS电路,从而可以利用具低功耗特性的绝热CMOS电路来降低整个电路系统的功耗,增强绝热CMOS电路的实用性。最后计算机模拟验证了TC/AC接口电路和AC/TC接口电路逻辑功能的正确性。展开更多
通过对传统CMOS与绝热CMOS接口电路的研究,在分析传统CMOS信号和绝热信号的时序关系的基础上提出了三种传统CMOS到绝热CMOS(Traditional CMOS to Adiabatic CMOS,TC/AC)接口电路的设计方案,实现了将传统CMOS信号到绝热信号的转变。最后H...通过对传统CMOS与绝热CMOS接口电路的研究,在分析传统CMOS信号和绝热信号的时序关系的基础上提出了三种传统CMOS到绝热CMOS(Traditional CMOS to Adiabatic CMOS,TC/AC)接口电路的设计方案,实现了将传统CMOS信号到绝热信号的转变。最后HSPICE模拟验证了所设计的三种TC/AC接口电路逻辑功能的正确性。展开更多
基金Project(XDB 0420200)supported by Strategy Priority Research Program(B)of China
文摘A low-temperature superconducting quantum interference device(low-Tc SQUID)can improve the depth of exploration.However,a low-Tc SQUID may lose its lock owing to oscillations in the current or the occurrence of spikes when the transmitter is switched off.If a low-Tc SQUID loses its lock,it becomes impossible for the low-Tc SQUID TEM system to function normally and stably for a long period of time.This hinders the practical use of the system.In field experiments,the transmitting current is accurately measured,the voltage overshoot and current spike data are recorded,and the gradient of the primary magnetic field at the center of the transmitting loop is calculated.After analyzing the results of field experiments,it was found that when the gradient of the primary magnetic field far exceeds the slew rate of a low-Tc SQUID,the low-Tc SQUID loses its lock.Based on the mechanisms of the transmitting oscillation,an RC serial and multi-parallel capacity snubber circuit used to suppress such oscillation is proposed.The results of simulation and field experiments show that,when using a 100 m×100 m transmitting loop,the gradient of the primary magnetic field is suppressed from 101.4 to 2.4 mT/s with a transmitting current of 40 A,and from 29.6 to 1.4 mT/s with a transmitting current of 20 A.Therefore,it can be concluded that the gradient of the primary magnetic field is below the slew rate of a low-Tc SQUID after adopting the proposed RC serial and multi-parallel capacity snubber circuit.In conclusion,the technique proposed in this paper solves the problem of a lost lock of a low-Tc SQUID,ensuring that the low-Tc SQUID TEM system functions stably for a long period of time,and providing technical assurance for ground TEM exploration at an additional depth.
文摘目的探讨肥胖少年的臂-踝脉搏波速度(brachial-ankle pulse wave velocity,BaPWV),与诱发心血管疾病发生的血生化指标的相关性。方法在北京市海淀区选取165例14~17岁的肥胖少年,男90例,女75例,测量体重、身高、血压后,计算BMI,采用动脉硬化检测仪测量臂-踝脉搏波速度(BaPWV),同时检测空腹血生化指标。分析BaPWV与肥胖相关指标,以及心血管疾病危险因素中血生化指标的关系。结果过度肥胖组的BaPWV,与总胆固醇(total cholesterol,TC)、低密度胆固醇(low density lipoprotein cholesterol,LDL-C)、三酰甘油(triglyceride,TG)呈正相关关系;与体重、体质指数(body mass index,BMI)、收缩压呈正相关关系。按照BaPWV测量值分组,BaPWV增高组(高于正常范围,>P_(95))的BaPWV,与总胆固醇(TC)、低密度胆固醇(LDL-C)呈正相关关系;与年龄、体重、体重指数(BMI)呈正相关关系。BaPWV增高与暴露于过度肥胖(BMI>P_(50))之间关联强度的比值比OR=2.159,OR的95%可信区间为1.011~4.613。说明过度肥胖会使BaPWV高于正常范围(>P_(95))的危险度增加2.159倍。结论总胆固醇(TC)和低密度胆固醇(LDL-C),与过度肥胖(BMI>P_(50)),以及BaPWV高于正常范围(>P_(95))有正相关性。过度肥胖会使BaPWV高于正常范围(>P_(95))的危险度增加。
文摘为了将绝热CMOS电路嵌入到传统电路系统中替代耗能较大的部件,本文研究并设计绝热CMOS电路和传统CMOS电路两者之间的接口电路:传统CMOS到绝热CMOS(Traditional CMOS to Adiabatic CMOS,TC/AC)的接口电路、绝热CMOS到传统CMOS(Adiabatic CMOS to Traditional CMOS,AC/TC)的接口电路。这样传统CMOS电路可以通过TC/AC接口电路来驱动绝热CMOS电路,绝热CMOS电路可以通过AC/TC接口电路来驱动传统CMOS电路,从而可以利用具低功耗特性的绝热CMOS电路来降低整个电路系统的功耗,增强绝热CMOS电路的实用性。最后计算机模拟验证了TC/AC接口电路和AC/TC接口电路逻辑功能的正确性。
文摘通过对传统CMOS与绝热CMOS接口电路的研究,在分析传统CMOS信号和绝热信号的时序关系的基础上提出了三种传统CMOS到绝热CMOS(Traditional CMOS to Adiabatic CMOS,TC/AC)接口电路的设计方案,实现了将传统CMOS信号到绝热信号的转变。最后HSPICE模拟验证了所设计的三种TC/AC接口电路逻辑功能的正确性。
