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A New Method to Calculate the Degree of Electromagnetic Impedance Matching in One-Layer Microwave Absorbers

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Chinese Physics Letters 2012年第3期29卷 247-250页

作者： MA Zhi CAO Chen-Tao liu qing-fang WANG Jian-Bo Key Laboratory for Magnetism and Magnetic Materials of Ministry of Education Lanzhou UniversityLanzhou 730000

A delta-function method is proposed to quantitatively evaluate the electromagnetic impedance matching *** electromagnetic parameters ofα-Fe/Fe_(3)B/Y_(2)O_(3)nanocomposites are applied to calculate the matching degree by the *** with reflection loss and quarter-wave principle theory,the method accurately reveals the intrinsic mechanism of microwave transmission and reflection properties.A possible honeycomb structure with promising high-performance microwave absorption,devised according to the method,is also proposed.

关键词： properties method matching

Enhanced Giant Magnetoimpedance Effect in Rapid Heat-Treated Fe-Based Amorphous Ribbons

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Chinese Physics Letters 2013年第3期30卷 150-153页

作者： ZHANG Yi DONG Juan FENG Er-Xi LUO Cai-Qin liu qing-fang WANG Jian-Bo Institute of Applied Magnetics Key Laboratory for Magnetism and Magnetic Materials of the Ministry of EducationLanzhou UniversityLanzhou 730000

An enhanced giant magnetoimpedance(GMI)effect of Fe-based amorphous ribbons is obtained by rapid heat *** structural investigations on the ribbon reveal the presence of two phases,i.e.a fine grained Fe3Si phase and a residual amorphous phase on rapid heat *** soft magnetic property is improved by rapid heat treatment;the crystal size and grain size of Fe_(3)Si *** maximum magnetoimpedance ratio obtained in the present study is 81%at 10 MHz,and the optimized heat-treated rate is 200℃/*** GMI curves are observed after the simultaneous rapid heat treatment and magnetic field *** suggests that tailoring of the nanocrystalline microstructures induced by optimum rapid heat treatment conditions can result in an excellent GMI effect.

关键词： grain treatment amorphous

3-D NUMERICAL STUDY OF LAMINAR AND TURBULENT FLOW INSIDE A 90-DEG-BEND SQUARE AND FLAT DUCT

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Journal of Hydrodynamics 1992年第4期4卷 97-108页

作者： liu qing-chao Chai fang-Kun Chen Zhen-xi Institute of Water Conservancy and Hydroelectric Power Research,Beijing 100044,P.R.China

With the application of body-fitted coordinate method and the standard k-epsilon equations,the rtumericat sotution to the averaged N-S equations is *** and turbu- tent flows inside a 90-Deg-Bent duct are studied,yield... 详细信息

关键词： 3—D laminar flow turbulent flow

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我的母亲刘清扬

回族研究 2005年第2期 163-174页

作者：刘方清中央编译局北京100032

1973年秋的一天,我突然接到中央专案组通知,让我去探视在监内的母亲.自1968年2月母亲在'文革'期间被抓走,我们已经6年没有见面了.母亲出了什么事?病了?还是……?我怀着忐忑不安的心情,赶到专案组指定的地点(复兴医院东侧的一个小楼),好... 详细信息

1973年秋的一天,我突然接到中央专案组通知,让我去探视在监内的母亲.自1968年2月母亲在'文革'期间被抓走,我们已经6年没有见面了.母亲出了什么事?病了?还是……?我怀着忐忑不安的心情,赶到专案组指定的地点(复兴医院东侧的一个小楼),好不容易才等到探视时间.一辆小车推着一个白发苍苍、双腿瘫软、面庞浮肿、目光呆滞的老人.

关键词：母亲刘清 “文革”期间 1973年 1968年专案组中央地点

Recurrent atrial tachycardia and atrial fribrillation after circumferential pulmonary vein ablation:What’s the difference?

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Chinese Medical Journal 2005年第21期118卷 1773-1778页

作者： liu Xing-peng LONG De-yong DONG Jian-zeng liu Xiao-qing fang Dong-ping HAO Peng MA Chang-sheng Department of Cardiology Beijing Anzhen Hospital Capital University of Medical Science Beijing 100029 China

Background Recurrent atrial tachyarrhythmia （ATa） after circumferential pulmonary vein ablation （CPVA） includes atrial tachycardia （AT） and atrial fribrillation （AF）. However, whether there are some differences in clinical course and mechanisms between the recurrent AT and the recurrent AF remained unclear. This study was conducted to investigate the incidence, mechanism, clinical course of the recurrent AT and AF in patients under *** One hundred and thirty consecutive patients （M/F = 95/35 ） with highly symptomatic ano multiple antiarrhythmic drugs （AADs） refractory paroxysmal （ n = 91 ） or persistent （ n = 39 ） AF were included. The ablation protocol consisted solely of two continuous circular lesions around the ipsilateral pulmonary veins （PV） guided by CARTO system. The endpoint of CPVA is PV isolation. For patients with recurrent ATa within 2 months after the initial procedure, cardioversion with direct current was attempted if the ATa lasted for more than 24 hours. A repeat ablation procedure was performed only for patients with AADs refractory recurrent ATa and at least followed up for 2 months after the initial *** Within 2 months after the initial procedure, 52 patients （40. 0% ） had experienced episodes of symptomatic recurrent ATa. Among them, 23 patients （44.2%） with recurred AT alone （AT group ）, 14 patients （26.9%） with recurred AF alone （AF group）, and 15 patients （28.8%） with recurred AT and AF （AT plus AF group）. The delayed cure rate （65.2%） in AT group was significant higher than that in AF group （21.4%, P〈0.05） and AF plus AT group （26.7%, P 〈0.05）. A repeat ablation was performed in 21 patients, including 6 patients with recurrent AT alone, 8 patients with recurrent AF alone, and 7 patients with recurrent AF plus AT. The mean number of PV gaps was 1.2 ± 0. 4 in AT group, which was significantly lower than that in AF group （2.6 ± 0. 7, P 〈 0.05） and AF plus AT group （2.0 ± 0.6, P 〈 0.05）. Delayed cure rate and number of PV

关键词： atrial fibrillation catheter ablation pulmonary vein

A novel chromatic dispersion 16/64-QAM system based on histogram monitoring technique for asynchronous amplitudehistogram

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Optoelectronics Letters 2013年第3期9卷 229-232页

作者： YAN Li-juan ZHU Bo liu Guo-qing HU fang-ren Department of Optical Information Technology Nanjing University of Posts and Telecommunications Nanjing210046 China

A novel chromatic dispersion （CD） monitoring technique based on asynchronous amplitude histogram （AAH） for higher order modulation formats is proposed in this paper. Without demodulating the signal, in the monitoring scheme, the received signal is sampled asynchronously, and thus clock information and high-speed sampling units are unnecessary, resulting in low cost and high reliability. Simulations of CD monitoring technique for non-return-to-zero/return-to-zero （NRZ/RZ） 16- and 64-quadrature amplitude modulation （QAM） systems with different optical signal-to- noise ratios （OSNRs） and duty cycles are investigated, and the tolerance of the scheme is also discussed. Simulation results show that the presented CD monitoring technique with high sensitivity can be applied to monitor the residual CD of a transmission link in the next-generation optical networks.

关键词： QAM系统监测技术异步采样直方图色散正交幅度调制信号噪声比下一代光网络

天山北坡城市群PM_(2.5)浓度时空分布特征及影响因素分析

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环境科学 2024年第3期45卷 1315-1327页

作者：王相男张喆刘方青新疆大学地理与遥感科学学院乌鲁木齐830046 新疆大学绿洲生态自治区重点实验室乌鲁木齐830046 智慧城市与环境建模自治区普通高校重点实验室乌鲁木齐830046

针对天山北坡城市群开展PM_(2.5)浓度时空分布特征和影响因素分析,对区域经济建设和环境保护具有积极的意义.通过地理加权回归(GWR)模型,利用MCD19A2气溶胶产品结合气象因子,反演得到天山北坡城市群2015~2021年3~11月的PM_(2.5)浓度时... 详细信息

针对天山北坡城市群开展PM_(2.5)浓度时空分布特征和影响因素分析,对区域经济建设和环境保护具有积极的意义.通过地理加权回归(GWR)模型,利用MCD19A2气溶胶产品结合气象因子,反演得到天山北坡城市群2015~2021年3~11月的PM_(2.5)浓度时空分布,继而实现变化趋势和影响因素分析.结果如下:(1)研究区PM_(2.5)浓度高值主要分布在天山北麓和古尔班通古特沙漠之间的绿洲城市群地带,呈现“四周低,中间高”和“西低东高”的空间分布特征,2015~2021年研究区的ρ(PM_(2.5))年均值为16.98μg·m^(-3),高值主要聚集在乌鲁木齐市市区部分,并向昌吉市和阜康市延伸递减;ρ(PM_(2.5))月均值分布规律与年均一致,但存在季节差异,表现为:秋季(20.32μg·m^(-3))>春季(18.25μg·m^(-3))>夏季(12.47μg·m^(-3)),春季和冬季聚集现象会更明显;(2)研究区PM_(2.5)浓度年均值在2015~2021年呈现下降趋势,3~10月均值同样表现为下降趋势,仅11月表现为略有升高;从PM_(2.5)浓度变化趋势空间分布分析,下降集中在主要城市市区部分,尤其是乌鲁木齐市市区部分及其周边地区减少幅度最大,变化最为剧烈;(3)研究区气温、气压与PM_(2.5)浓度呈现正相关效应,而相对湿度,风速,大气边界层高度,降水量与PM_(2.5)浓度呈现负相关效应;各因子影响程度从高向低排列为:大气边界层高度>相对湿度>气压>气温>风速>降水量.

关键词：地理加权回归(GWR)模型天山北坡城市群时空分布特征变化趋势影响因素分析

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膨胀土堑坡雨季失稳的突变模型

重庆交通大学学报（自然科学版） 2009年第2期28卷 255-258页

作者：刘清芳长沙理工大学交通运输学院湖南长沙410076

以受结构面的控制膨胀土堑坡滑坡失稳为例,考虑降雨条件下,滑面介质的应变软化和水致弱化,提出了一个简单的考虑吸水膨胀的力学模型,并利用突变理论分析其失稳破坏的力学机制。在突变分析中,通过尖点突变模型,分析了刚度比、含水量等因... 详细信息

以受结构面的控制膨胀土堑坡滑坡失稳为例,考虑降雨条件下,滑面介质的应变软化和水致弱化,提出了一个简单的考虑吸水膨胀的力学模型,并利用突变理论分析其失稳破坏的力学机制。在突变分析中,通过尖点突变模型,分析了刚度比、含水量等因素对滑坡的触发作用。结果表明:滑坡的演化过程是内外部因素共同作用的结果,降雨导致结构面介质膨胀软化的原因属于外部的触发因素。在膨胀土堑坡的加固防护中,应当充分地考虑水的治理。

关键词：尖点突变应变软化水致弱化刚度比柔性支挡结构

Preparation of FeCoNi medium entropy alloy from Fe^(3+)-Co^(2+)-Ni^(2+)solution system

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 92-101页

作者： Zongyou Cheng qing Zhao Mengjie Tao Jijun Du Xingxi Huang Chengjun liu Key Laboratory for Ecological Metallurgy of Multimetallic Mineral(Ministry of Education) Northeastern UniversityShenyang 110819China School of Metallurgy Northeastern UniversityShenyang 110819China Engineering Research Center of Frontier Technologies for Low-carbon Steelmaking(Ministry of Education) Shenyang 110819China

In recent years,medium entropy alloys have become a research hotspot due to their excellent physical and chemical *** controlling reasonable elemental composition and processing parameters,the medium entropy alloys can exhibit similar properties to high entropy alloys and have lower *** this paper,a FeCoNi medium entropy alloy precursor was prepared via sol-gel and coprecipitation methods,respectively,and FeCoNi medium entropy alloys were prepared by carbothermal and hydrogen *** phases and magnetic properties of FeCoNi medium entropy alloy were *** showed that FeCoNi medium entropy alloy was produced by carbothermal and hydrogen reduction at 1500℃.Some carbon was detected in the FeCoNi medium entropy alloy prepared by carbothermal *** alloy prepared by hydrogen reduction was uniform and showed a relatively high ***,the hydrogen reduction product exhibited better saturation magnetization and lower coercivity.

关键词： medium entropy alloy sol-gel co-precipitation carbothermal hydrogen reduction