电压调控磁各向异性磁隧道结(voltage controlled magnetic anisotropy magnetic tunnel junction, VCMA-MTJ)作为磁随机存储器(magnetic random access memory, MRAM)的核心器件,具有读写速度快、功耗低、与CMOS工艺相兼容等优点,现已...电压调控磁各向异性磁隧道结(voltage controlled magnetic anisotropy magnetic tunnel junction, VCMA-MTJ)作为磁随机存储器(magnetic random access memory, MRAM)的核心器件,具有读写速度快、功耗低、与CMOS工艺相兼容等优点,现已得到国内外学者的广泛关注.然而随着VCMA-MTJ尺寸不断缩小、MRAM存储容量不断增大,工艺偏差对MTJ性能的影响变得越来越显著,甚至会引起VCMA-MTJ电路的读写错误.本文在充分考虑磁控溅射薄膜生长工艺中自由层厚度偏差(γtf)、氧化势垒层厚度偏差(γtox)以及离子束刻蚀工艺中由侧壁再沉积层引入的刻蚀工艺稳定因子(α)偏差影响的情况下,给出了基于工艺偏差的VCMA-MTJ电学模型,并将该模型应用到VCMA-MTJ读写电路中,研究了工艺偏差对上述电路读写错误率的影响.结果表明:当γtf≥13%, γtox≥11%时, VCMA-MTJ将无法实现磁化状态的有效切换;当α≤0.7时, VCMA-MTJ磁化方向的进动过程变得不稳定.进一步地, VCMA-MTJ电路的读错误率和写错误率也将随着工艺偏差的增大而增大.研究表明,通过增大外加电压(Vb)和减小外加电压脉冲宽度(tpw)可有效降低VCMA-MTJ电路的写错误率,增大电路的读驱动电压(Vdd)可有效降低VCMA-MTJ电路的读错误率.展开更多
目的探讨磁刺激神经调控治疗运动发育迟缓患儿的效果。方法选取2017年1月—2020年3月该院收治的100例运动发育迟缓患儿,按照随机数字表法分为两组,每组50例。对照组采用传统康复治疗,研究组采用磁刺激神经调控治疗。比较两组患儿的临床...目的探讨磁刺激神经调控治疗运动发育迟缓患儿的效果。方法选取2017年1月—2020年3月该院收治的100例运动发育迟缓患儿,按照随机数字表法分为两组,每组50例。对照组采用传统康复治疗,研究组采用磁刺激神经调控治疗。比较两组患儿的临床疗效、运动功能及发育情况。结果研究组的临床治疗总有效率为96.00%,高于对照组的80.00%,差异有统计学意义(P<0.05)。治疗后,两组的88项粗大运动功能评分量表(gross motor function measure,GMFM-88)各项评分均高于同组治疗前,且研究组的GMFM各项评分均高于对照组,组间差异有统计学意义(P<0.05)。治疗后,两组的各项Gesell发育诊断量表评分均高于同组治疗前,且研究组的各项Gesell发育诊断量表评分均高于对照组,组间差异有统计学意义(P<0.05)。结论采用磁刺激神经调控治疗运动发育迟缓患儿,可有效改善其运动功能,促进患儿发育,疗效确切。展开更多
Objectives Partial hepatectomy induces a rapid transformation within the remnant liver, prompting a wave of hepatocyte mitosis which abates when the lost cell mass has been recovered. The mechanism of co-ordinated con...Objectives Partial hepatectomy induces a rapid transformation within the remnant liver, prompting a wave of hepatocyte mitosis which abates when the lost cell mass has been recovered. The mechanism of co-ordinated control of metabolism and maintenance of function during this period of dynamic change is incompletely understood. Furthermore, the biochemical basis of growth regulation in the regenerating liver has not been well defined. We have studied human liver regeneration using in vivo 31-phosphorus magnetic resonance spectroscopy (31 P MRS). This non-invasive technique allows assay of high-energy phosphate compounds and also of phospholipid metabolites thought to be involved in cellular renewal processes.Methods Five patients undergoing liver resection were studied. Hepatic metabolism was evaluated using 31P MRS before surgery and on postoperative days 2,4,6 and 14. Estimation of liver volume by magnetic resonance imaging and blood sampling for biochemistry were performed at the same time points.Results We found that the regenerative response following loss of liver parenchyma produced a reversible decline in energy state which necessitated compensatory adjustments in liver synthetic and excretory (unctions. Volume regain was associated with alterations in phospholipid metabolism, which normalized when the hepatic growth spurt was completed.Conclusion These observations indicate that modulation of hepatocyte energy economy is necessary for the integrated recovery of liver cell mass and function. We propose that deficient hepatic energy production may explain the mechanism of liver failure after hepatectomy, and suggest that in vivo measurement of liver metabolism may provide a rational basis for the development and evaluation of hepatic support strategies.展开更多
Recently, artificial intelligence technique is increasingly receiving attention in solving complex and practical problem and they are widely applying in electrical machine domain. The authors consider also the direct ...Recently, artificial intelligence technique is increasingly receiving attention in solving complex and practical problem and they are widely applying in electrical machine domain. The authors consider also the direct torque control （DTC） as an alternative to conventional methods of control by pulse width modulation （PWM） and by Field oriented control （FOC）, so the application of the DTC based on artificial intelligence can show more advantages and simplified control algorithms with high performance. For this reason, the objectives of this paper can be divided into two parts, the first part is to apply neural networks and fuzzy logic techniques to the DTC control in the presence of a loop speed control comparing to the conventional regulators （as PI） to show the feasibility of these approaches, the second part is to further improve the performance of the neural network by using a neural-fuzzy regulator which combine the advantages of two techniques. Simulation results confirm the validity of the proposed techniques.展开更多
Vehicle height and leveling control of electronically controlled air suspension(ECAS) still poses theoretical challenges for researchers that have not been adequately addressed in prior research. This paper investigat...Vehicle height and leveling control of electronically controlled air suspension(ECAS) still poses theoretical challenges for researchers that have not been adequately addressed in prior research. This paper investigates the design and verification of a new controller to adjust the vehicle height and to regulate the roll and pitch angles of the vehicle body(leveling control) during the height adjustment procedures. A nonlinear mechanism model of the vehicle height adjustment system is formulated to describe the dynamic behaviors of the system. By using mixed logical dynamical(MLD) approach, a novel control strategy is proposed to adjust the vehicle height by controlling the on-off statuses of the solenoid valves directly. On this basis, a correction algorithm is also designed to regulate the durations of the on-off statuses of the solenoid valves based on pulse width modulated(PWM) technology, thus the effective leveling control of the vehicle body can be guaranteed. Finally, simulations and vehicle tests results are presented to demonstrate the effectiveness and applicability of the proposed control methodology.展开更多
文摘目的探讨磁刺激神经调控治疗运动发育迟缓患儿的效果。方法选取2017年1月—2020年3月该院收治的100例运动发育迟缓患儿,按照随机数字表法分为两组,每组50例。对照组采用传统康复治疗,研究组采用磁刺激神经调控治疗。比较两组患儿的临床疗效、运动功能及发育情况。结果研究组的临床治疗总有效率为96.00%,高于对照组的80.00%,差异有统计学意义(P<0.05)。治疗后,两组的88项粗大运动功能评分量表(gross motor function measure,GMFM-88)各项评分均高于同组治疗前,且研究组的GMFM各项评分均高于对照组,组间差异有统计学意义(P<0.05)。治疗后,两组的各项Gesell发育诊断量表评分均高于同组治疗前,且研究组的各项Gesell发育诊断量表评分均高于对照组,组间差异有统计学意义(P<0.05)。结论采用磁刺激神经调控治疗运动发育迟缓患儿,可有效改善其运动功能,促进患儿发育,疗效确切。
文摘Objectives Partial hepatectomy induces a rapid transformation within the remnant liver, prompting a wave of hepatocyte mitosis which abates when the lost cell mass has been recovered. The mechanism of co-ordinated control of metabolism and maintenance of function during this period of dynamic change is incompletely understood. Furthermore, the biochemical basis of growth regulation in the regenerating liver has not been well defined. We have studied human liver regeneration using in vivo 31-phosphorus magnetic resonance spectroscopy (31 P MRS). This non-invasive technique allows assay of high-energy phosphate compounds and also of phospholipid metabolites thought to be involved in cellular renewal processes.Methods Five patients undergoing liver resection were studied. Hepatic metabolism was evaluated using 31P MRS before surgery and on postoperative days 2,4,6 and 14. Estimation of liver volume by magnetic resonance imaging and blood sampling for biochemistry were performed at the same time points.Results We found that the regenerative response following loss of liver parenchyma produced a reversible decline in energy state which necessitated compensatory adjustments in liver synthetic and excretory (unctions. Volume regain was associated with alterations in phospholipid metabolism, which normalized when the hepatic growth spurt was completed.Conclusion These observations indicate that modulation of hepatocyte energy economy is necessary for the integrated recovery of liver cell mass and function. We propose that deficient hepatic energy production may explain the mechanism of liver failure after hepatectomy, and suggest that in vivo measurement of liver metabolism may provide a rational basis for the development and evaluation of hepatic support strategies.
文摘Recently, artificial intelligence technique is increasingly receiving attention in solving complex and practical problem and they are widely applying in electrical machine domain. The authors consider also the direct torque control （DTC） as an alternative to conventional methods of control by pulse width modulation （PWM） and by Field oriented control （FOC）, so the application of the DTC based on artificial intelligence can show more advantages and simplified control algorithms with high performance. For this reason, the objectives of this paper can be divided into two parts, the first part is to apply neural networks and fuzzy logic techniques to the DTC control in the presence of a loop speed control comparing to the conventional regulators （as PI） to show the feasibility of these approaches, the second part is to further improve the performance of the neural network by using a neural-fuzzy regulator which combine the advantages of two techniques. Simulation results confirm the validity of the proposed techniques.
基金supported by the National Natural Science Foundation of China(Grant Nos.51375212,61403172&51305167)Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)Key Research and Development Program of Jiangsu Province(Grant No.BE2016149)
文摘Vehicle height and leveling control of electronically controlled air suspension(ECAS) still poses theoretical challenges for researchers that have not been adequately addressed in prior research. This paper investigates the design and verification of a new controller to adjust the vehicle height and to regulate the roll and pitch angles of the vehicle body(leveling control) during the height adjustment procedures. A nonlinear mechanism model of the vehicle height adjustment system is formulated to describe the dynamic behaviors of the system. By using mixed logical dynamical(MLD) approach, a novel control strategy is proposed to adjust the vehicle height by controlling the on-off statuses of the solenoid valves directly. On this basis, a correction algorithm is also designed to regulate the durations of the on-off statuses of the solenoid valves based on pulse width modulated(PWM) technology, thus the effective leveling control of the vehicle body can be guaranteed. Finally, simulations and vehicle tests results are presented to demonstrate the effectiveness and applicability of the proposed control methodology.
