本文研究了旋磁铁氧体材料在不同条件下(磁化状态,大块材料和离散的阵列形式)对低频电磁波的吸收性能以及铁氧体基元间的耦合作用对吸收带宽的影响.研究结果表明,通过旋磁铁氧体在吸波材料中的结构设计可以实现对低频电磁波的高效吸收....本文研究了旋磁铁氧体材料在不同条件下(磁化状态,大块材料和离散的阵列形式)对低频电磁波的吸收性能以及铁氧体基元间的耦合作用对吸收带宽的影响.研究结果表明,通过旋磁铁氧体在吸波材料中的结构设计可以实现对低频电磁波的高效吸收.文中4 mm大块薄层旋磁铁氧体反射率的–10 d B频点能低至0.48 GHz,并可以通过调整偏置磁场的大小或者离散铁氧体基元的大小灵活地改变共振频率.引入不同尺寸的基元形成的多谐振峰及其相互的耦合可以有效拓展–10 d B带宽,并且这种展宽作用在不同的磁化状态下都是有效的.当采用横向偏置场700 Oe时,两基元吸波材料–10 d B带宽可达单个基元各自作用带宽之和的105.7%.展开更多
Background:The main purpose of this article is to explore the differences between mild-to-moderate acute stroke patients with hyperhomocysteine and similar patients with normal homocysteine in risk factors,cerebral ar...Background:The main purpose of this article is to explore the differences between mild-to-moderate acute stroke patients with hyperhomocysteine and similar patients with normal homocysteine in risk factors,cerebral arterial stenosis,neurological deficit,cognitive function impairment.The subjects included gender,body mass index,whether to combine hypertension,blood glucose level,blood lipid,national institutes of health stroke scale(NIHSS)score,whether to combine cerebral arterial stenosis and Montreal cognitive assessment scores.Method:Twentyseven mild-to-moderate acute stroke patients with hyperhomocysteinemia(NIHSS score≤15 points)and 34 mildto-moderate acute stroke patients without hyperhomocysteinemia were admitted in the past year as the research objects.N=27 stroke patients with hyperhomocysteine were set as the experimental group,and N=34 patients without hyperhomocysteine were set as the control group.A retrospective study of clinical data from both groups of patients was conducted.Compare the data of the 2 groups of patients with differences in the above study data,and then explore the specific impact of hyperhomocysteinemia on the above experimental indicators.Results:(1)NIHSS scores of patients in the experimental group were higher than those in the control group,and the difference was statistically significant(P<0.05).(2)The incidence of cerebrovascular stenosis(including intracranial and extracranial arteries)in the experimental group was significantly higher than that in the control group,and the difference was statistically significant(P<0.05).(3)The degree of cognitive impairment in the experimental group was significantly higher than that in the control group,with a statistically significant difference(P<0.05).(4)The proportion of male patients in the study group was significantly higher than that in the control group(P<0.05).(5)The level of homocysteine in the experimental group was positively correlated with NIHSS score(r=0.602,P<0.05)and negatively correlated with Montreal cognitive assessment score(r=−0.551,P<0.05).Conclusion:Mildto-moderate stroke patients with hyperhomocysteinemia are more likely to have severe neurological deficits,and most patients will be associated with more severe intracranial arterial and extracranial arterial stenosis.Mild-tomoderate stroke patients with high homocysteine are more likely to develop cognitive impairment.Finally,high homocysteine levels were associated with neurological impairment and cognitive impairment.Therefore,clinically,patients with acute stroke and hyperhomocysteinemia should be actively treated with hypohomocysteine,and it is recommended to improve cerebrovascular evaluation(computed tomography angiography or magnetic resonance angiography)for hospitalized patients even with hemorrhagic stroke.Stroke patients with hyperhomocysteinemia should be given more aggressive treatment(ischemic stroke patients should be given more optimized antithrombotic therapy,hemorrhagic stroke patients should be given more aggressive dehydrating cranial pressure reduction,et al.).Finally,brain protectants and cognitive function improvement therapy can be given in advance to prevent cognitive function deterioration.展开更多
文摘本文研究了旋磁铁氧体材料在不同条件下(磁化状态,大块材料和离散的阵列形式)对低频电磁波的吸收性能以及铁氧体基元间的耦合作用对吸收带宽的影响.研究结果表明,通过旋磁铁氧体在吸波材料中的结构设计可以实现对低频电磁波的高效吸收.文中4 mm大块薄层旋磁铁氧体反射率的–10 d B频点能低至0.48 GHz,并可以通过调整偏置磁场的大小或者离散铁氧体基元的大小灵活地改变共振频率.引入不同尺寸的基元形成的多谐振峰及其相互的耦合可以有效拓展–10 d B带宽,并且这种展宽作用在不同的磁化状态下都是有效的.当采用横向偏置场700 Oe时,两基元吸波材料–10 d B带宽可达单个基元各自作用带宽之和的105.7%.
文摘Background:The main purpose of this article is to explore the differences between mild-to-moderate acute stroke patients with hyperhomocysteine and similar patients with normal homocysteine in risk factors,cerebral arterial stenosis,neurological deficit,cognitive function impairment.The subjects included gender,body mass index,whether to combine hypertension,blood glucose level,blood lipid,national institutes of health stroke scale(NIHSS)score,whether to combine cerebral arterial stenosis and Montreal cognitive assessment scores.Method:Twentyseven mild-to-moderate acute stroke patients with hyperhomocysteinemia(NIHSS score≤15 points)and 34 mildto-moderate acute stroke patients without hyperhomocysteinemia were admitted in the past year as the research objects.N=27 stroke patients with hyperhomocysteine were set as the experimental group,and N=34 patients without hyperhomocysteine were set as the control group.A retrospective study of clinical data from both groups of patients was conducted.Compare the data of the 2 groups of patients with differences in the above study data,and then explore the specific impact of hyperhomocysteinemia on the above experimental indicators.Results:(1)NIHSS scores of patients in the experimental group were higher than those in the control group,and the difference was statistically significant(P<0.05).(2)The incidence of cerebrovascular stenosis(including intracranial and extracranial arteries)in the experimental group was significantly higher than that in the control group,and the difference was statistically significant(P<0.05).(3)The degree of cognitive impairment in the experimental group was significantly higher than that in the control group,with a statistically significant difference(P<0.05).(4)The proportion of male patients in the study group was significantly higher than that in the control group(P<0.05).(5)The level of homocysteine in the experimental group was positively correlated with NIHSS score(r=0.602,P<0.05)and negatively correlated with Montreal cognitive assessment score(r=−0.551,P<0.05).Conclusion:Mildto-moderate stroke patients with hyperhomocysteinemia are more likely to have severe neurological deficits,and most patients will be associated with more severe intracranial arterial and extracranial arterial stenosis.Mild-tomoderate stroke patients with high homocysteine are more likely to develop cognitive impairment.Finally,high homocysteine levels were associated with neurological impairment and cognitive impairment.Therefore,clinically,patients with acute stroke and hyperhomocysteinemia should be actively treated with hypohomocysteine,and it is recommended to improve cerebrovascular evaluation(computed tomography angiography or magnetic resonance angiography)for hospitalized patients even with hemorrhagic stroke.Stroke patients with hyperhomocysteinemia should be given more aggressive treatment(ischemic stroke patients should be given more optimized antithrombotic therapy,hemorrhagic stroke patients should be given more aggressive dehydrating cranial pressure reduction,et al.).Finally,brain protectants and cognitive function improvement therapy can be given in advance to prevent cognitive function deterioration.
