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Multi-stability involved mixed bursting within the coupled pre-Btzinger complex neurons 被引量:2
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作者 王子剑 段利霞 曹秦禹 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第7期227-233,共7页
Neurons in the pre-B6tzinger complex within the mammalian brain stem play important roles in the generation of respiratory rhythms. Experimental observations show that some neurons can exhibit novel mixed bursting act... Neurons in the pre-B6tzinger complex within the mammalian brain stem play important roles in the generation of respiratory rhythms. Experimental observations show that some neurons can exhibit novel mixed bursting activities. In this paper, based on a mathematical model proposed by Butera, we show how the mixed bursting activities depend on the potassium current in the coupled pre-Botzinger complex. Using fast-slow decomposition and bifurcation analysis, we investigate the dynamics of mixed bursting, as well as the mechanisms of transition between different mixed bursting patterns. We find that mixed bursting involves different bistability, and it is the transition state of two types of regular burstings. 展开更多
关键词 pre-Botzinger complex fast-slow decomposition BIFURCATION mixed bursting
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Synthesis of Cu-Doped Mixed-Phase TiO_2 with the Assistance of Ionic Liquid by Atmospheric-Pressure Cold Plasma
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作者 詹志彬 底兰波 +1 位作者 张秀玲 李燕春 《Plasma Science and Technology》 SCIE EI CAS CSCD 2016年第5期494-499,共6页
An atmospheric-pressure dielectric barrier discharge (DBD) gas-liquid cold plasma was employed to synthesize Cu-doped TiO~ nanoparticles in an aqueous solution with the assistance of [C2MIM]BF4 ionic liquid (IL) a... An atmospheric-pressure dielectric barrier discharge (DBD) gas-liquid cold plasma was employed to synthesize Cu-doped TiO~ nanoparticles in an aqueous solution with the assistance of [C2MIM]BF4 ionic liquid (IL) and using air as the working gas. The influences of the discharge voltage, IL and the amount of copper nitrite were investigated. X-ray diffraction, N2 adsorption-desorption measurements and UV-Vis spectroscopy were adopted to characterize the samples. The results showed that the specific surface area of TiO2 was promoted with Cu-doping (from 57.6 m^2.g^-1 to 106.2 m^2.g^-1 with 3% Cu-doping), and the content of anatase was increased. Besides, the band gap energy of TiO~ with Cu-doping decreased according to the UV-Vis spec- troscopy test. The 3%Cu-IL-TiO2 samples showed the highest eificiency in degrading methylene blue (MB) dye solutions under simulated sunlight with an apparent rate constant of 0.0223 min-1, which was 1.2 times higher than that of non-doped samples. According to the characterization results, the reasons for the high photocatalytic activity were discussed. 展开更多
关键词 dielectric barrier discharge (DBD) gas-liquid cold plasma atmospheric pres-sure mixed-phase Ti02 Cu-doped
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预混合和预沉积MIEX-超滤处理含藻水的膜污染控制
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作者 马聪 张萌 +1 位作者 王冠英 王亮 《天津工业大学学报》 CAS 北大核心 2024年第1期42-49,共8页
为了降低超滤处理含藻水的膜污染,探究了预混合和预沉积磁性离子交换树脂(MIEX)超滤处理含藻水的膜污染控制。对实验过程中的总阻力、可逆阻力及不可逆阻力进行分析,并使用扫描电子显微镜、三维荧光光谱、不可逆污染组分及超滤过滤模型... 为了降低超滤处理含藻水的膜污染,探究了预混合和预沉积磁性离子交换树脂(MIEX)超滤处理含藻水的膜污染控制。对实验过程中的总阻力、可逆阻力及不可逆阻力进行分析,并使用扫描电子显微镜、三维荧光光谱、不可逆污染组分及超滤过滤模型对膜污染机理进行探究。结果表明:在相同投加量下,预沉积MIEX比预混合MIEX膜污染的控制更好,最大预沉积量为235.2 mL/m^(2)时,膜污染控制最好,此时预沉积MIEX的总阻力、可逆阻力和不可逆阻力分别比预混合MIEX的相应值低52.7%、65.7%和50.1%;蛋白质均是造成2种投加方式不可逆阻力的主要原因;随着预混合投加量的增加,滤饼层厚度从4.82 m降低至4.07 m,滤饼层内藻细胞及胞外有机物(EOM)含量降低;在预沉积MIEX中,随着沉积量的增加,沉积层形态发生变化,当沉积量最大时,沉积层拦截较多藻细胞和EOM,形成明显的藻类滤饼层。 展开更多
关键词 超滤 磁性离子交换树脂 含藻水 膜污染 预混合 预沉积
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A novel thermoregulated phosphine ligand used for the Rh-catalyzed hydroformylation of mixed C_(11-12) olefins in aqueous/organic biphasic system 被引量:2
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作者 Zhi Jiang Ji,Jing Yang Jiang,Yan Hua Wang State Key Laboratory of Fine Chemicals,Dalian University of Technology,Dalian 116012,China 《Chinese Chemical Letters》 SCIE CAS CSCD 2010年第5期515-518,共4页
A novel thermoregulated phosphine ligand PhP(CHCHO)CH(n=22) was synthesized and used for the Rh-catalyzed hydroformylation of mixed Colefins in aqueous/organic biphasic system.Under the optimized conditions,pressure =... A novel thermoregulated phosphine ligand PhP(CHCHO)CH(n=22) was synthesized and used for the Rh-catalyzed hydroformylation of mixed Colefins in aqueous/organic biphasic system.Under the optimized conditions,pressure =5 MPa (H:CO=1:1),phosphine/Rh =13(molar ratio),reaction time =6 h and temperature =130℃,the conversion of Colefins and the yield of aldehyde are 99%and 94%,respectively.The catalyst retained in aqueous phase can be easily separated from the product-containing organic phase by simple phase separation and the catalytic activity remains almost constant after four consecutive cycles. 展开更多
关键词 Thermoregulated phosphine ligand mixed C11-12 olefins HYDROFORMYLATION RHODIUM
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Synergistic Effect in Mixed Capillary Gas Chromatographic Stationap Phases Containing Heptakis(2,3,6-tri-o-pentyl)-β-cyclodextrin and Dibenzo-18-crown-6 被引量:1
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作者 Li Ming YUAN Ruo Nong FU +3 位作者 Xue Xian CHEN Shi Hong GUl Rong Ji DAI (Chemistry Department of Yunnan Normal University.Kunming 650092)(Department of Chemical Engineering.Beijing institute of Technology,BEijing 100081)(Solar Energy Research Institute ofyunna 《Chinese Chemical Letters》 SCIE CAS CSCD 1999年第3期223-226,共4页
used-silical capillary columns containing heptakis(2、3、6-tri-o-pentyl)-β-cyclodextrinand dibenzo-18-crown-6 were prepared.By studying the selectivity of mixed stationary phases forsome solute pairs.as well a... used-silical capillary columns containing heptakis(2、3、6-tri-o-pentyl)-β-cyclodextrinand dibenzo-18-crown-6 were prepared.By studying the selectivity of mixed stationary phases forsome solute pairs.as well as comparing with the heptakis(2.3、6-tri-O-pentyl)-β-cyclodextrin and thedibenzo-18-crown-6 used as individual stationary phase、the synergistic effects were observed.These effects were affected by the column temperature.mixed ratio and linear velocity of carrier gas. 展开更多
关键词 Gas chromatography mixed stationary phase synergistic effect heptakis(2.3.6-tri-o-pentyl)-β-cyclodextrin DIBENZO-18-CROWN-6
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Ce_xTi_(1-x)O_2 Mixed Oxides Supported CuO Catalyst for NO Reduction by CO 被引量:1
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作者 楼莉萍 蒋晓原 +3 位作者 陈英旭 吕光烈 周仁贤 郑小明 《Journal of Rare Earths》 SCIE EI CAS CSCD 2003年第3期331-336,共6页
Ce x Ti 1- x O 2 mixed oxides of different mole ratios ( x =0, 0.1, 0.2~0.9, 1.0) were prepared by co precipitation of TiCl 4 with Ce(NO 3) 3 and then loaded with different amounts of CuO. The effe... Ce x Ti 1- x O 2 mixed oxides of different mole ratios ( x =0, 0.1, 0.2~0.9, 1.0) were prepared by co precipitation of TiCl 4 with Ce(NO 3) 3 and then loaded with different amounts of CuO. The effects of CuO on NO+CO reaction were investigated, and the structure and reductive properties of various CuO/Ce x Ti 1- x O 2 were characterized by the methodologies of BET, TPR and XRD. The results show that different Ce/Ti mole ratios and calcination temperatures induce changes of structure and reductive properties of the Ce x Ti 1- x O 2 mixed oxides. When x =0.1~0.5, amorphous CeTi 2O 6 phase mainly forms at 650 ℃ compared to the formation of CeTi 2O 6 which crystallizes at 800 ℃. When x >0.6, some TiO 2 enters the CeO 2 lattice and a CeO 2 TiO 2 solid solution is formed. The activity of 6%CuO/Ce x Ti 1- x O 2 calcined at 650 ℃ is largely affected by the x values, which is the highest when x =0.3, 0.4 and 0.9. The NO conversion reaches 70% at a reaction temperature of 150 ℃. By comparison, the x values have little effect on the activity of 6%CuO/Ce x Ti 1- x O 2 calcined at 800 ℃ . There are strong interactions between CuO and CeTi 2O 6, i.e., formation of the CeTi 2O 6 phase shifts the CuO reduction peak temperature from 380 to 200 ℃, and CuO, in turn, shifts the CeTi 2O 6 reduction peak temperature from 600 to 300 ℃. 展开更多
关键词 catalitic chemistry Ce x Ti 1- x O 2 mixed oxides CuO/Ce x Ti 1- x O 2 catalysts CeTi 2O 6 phase NO+CO reaction activity rare earths
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On the Mixed Propagator Approach to ρ-ω Mixing
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作者 YAN Mu-Lin JIANG Ji-Hao WANG Xiao-Jun 《Communications in Theoretical Physics》 SCIE CAS CSCD 2002年第8期195-199,共5页
The mixed propagator (MP) approach to ρ-ω mixing is discussed. It is found that under the pole-approximation assumption the results of MP approach is not compatible both with the effective Lagrangian theory andwith ... The mixed propagator (MP) approach to ρ-ω mixing is discussed. It is found that under the pole-approximation assumption the results of MP approach is not compatible both with the effective Lagrangian theory andwith the experiment measurement criterion. To overcome these inconsistent, we propose a new MP approach in whichthe physical states of ρ and ω are determined by the requirement of experimental measurement to meson resonance. Interms of this new MP approach, the EM pion form factor Fπ and form factors of ρo →π0γ and of ω→πo γ are derived.The results of Fπ are in good agreement with data. The form factor of ρo →π0γ exhibits a hidden charge-asymmetryenhancement effect which agrees with the prediction of the effective Lagrangian theory. 展开更多
关键词 ISOSPIN breaking VMD ρ-ω mixing DECAY of vector MESONS
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MIXED MODE SCC OF 18-8 STAINLESS STEEL IN BOILING 42% MgCl_2 SOLUTION
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作者 GAO Hua CAO Weijie ZHOU Deqi WANG Ruizhen Shanghai University of Engineering Science,Shanghai,China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1992年第8期104-109,共6页
A series of mixed mode tests were carried out on 18-8 stainless steel in boiling 42% MgCl_2 solution.The results show that for any K_Ⅱ/K_Ⅰ ratio,the SCC direction coin- cides well with the crack tip maximum normal s... A series of mixed mode tests were carried out on 18-8 stainless steel in boiling 42% MgCl_2 solution.The results show that for any K_Ⅱ/K_Ⅰ ratio,the SCC direction coin- cides well with the crack tip maximum normal stress plane,while the SCC resistance of the material reduces as the ratio of K_Ⅱ/K_Ⅰ increases.The experimental results were discussed in the light of anode dissolving mechanism and the effect of mixed mode loading on crack tip stress and strain.It is concluded that for fracture analysis if mixed mode cracks were simply taken into account as mode Ⅰ cracks,and only mode Ⅰ testing results as mode Ⅰ fracture criter- ion were employed,it may not be safe. 展开更多
关键词 18-8 stainless steel stress corrosion mixed mode
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Effect of Calcination Temperature on Structure and O_2 Desorption Properties of Ce_xPr_(1-x)O_(2-δ) Mixed Oxides
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作者 闫宗兰 石军 +2 位作者 步雅璠 赵鹏英 王谌 《Journal of Rare Earths》 SCIE EI CAS CSCD 2007年第S2期35-39,共5页
A series of CexPr1-xO2-δ (x=0, 0.5, 0.9, 1.0) mixed oxide calcined at different temperatures were synthesized by sol-gel method and characterized by Raman, XRD and O2-TPD techniques. When x=0.9, only a cubic phase Ce... A series of CexPr1-xO2-δ (x=0, 0.5, 0.9, 1.0) mixed oxide calcined at different temperatures were synthesized by sol-gel method and characterized by Raman, XRD and O2-TPD techniques. When x=0.9, only a cubic phase CeO2 is observed. When x=0.5, the compound was combined by Pr6O11 and CeO2 mixed oxides. For CexPr1-xO2-δ (x=0.5, 0.9)samples 465 cm-1 Raman peak is attributed to the Raman active F2g mode of CeO2. The broad peak at about 570 cm-1 can be linked to lattice defects resulting in oxygen vacancies. The crystallite size of the samples increased as increasing the calcined temperature. But the increased value of Ce0.9Pr0.1O2-δ and Ce0.5Pr0.5O2-δ is smaller than single CeO2 and Pr6O11 obviously. It reveals that the insertion of Pr atom into the ceria lattice could enhance the sintering resistance and thermal stability of the mixed oxides. Calcination temperatures had great effect on the peak intensity for CeO2 but less effect on Ce0.8Pr0.2O2-δ in Raman spectra, and it may be caused by the colors transformation of the mixed oxides. The result of O2-TPD experiment indicates that the formation of solid solution has elevation the stabilization and thermal stability of the mixed oxides. 展开更多
关键词 CexPr1-xO2-δ mixed oxides O2-TPD rare earths
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HBV PreS2+S/IFN-α融合基因真核表达载体的构建及其表达 被引量:3
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作者 陈红梅 白雪帆 +3 位作者 潘蕾 李光玉 韦三华 黄长形 《中国病毒学》 CSCD 2002年第4期312-314,共3页
构建含HBVPrdS2 +S和IFN α融合基因的真核表达载体pcDNA3.1.S2S/IFN α并在真核细胞中进行表达。应用重叠延伸剪切技术 (splicingbyoverlappingextension ,简称SOE)经两次PCR获得嵌合基因片段S2S/IFN α ,回收后直接克隆到 pcDNA3.1V5 ... 构建含HBVPrdS2 +S和IFN α融合基因的真核表达载体pcDNA3.1.S2S/IFN α并在真核细胞中进行表达。应用重叠延伸剪切技术 (splicingbyoverlappingextension ,简称SOE)经两次PCR获得嵌合基因片段S2S/IFN α ,回收后直接克隆到 pcDNA3.1V5 /HisTOPOTA克隆载体 ,得到真核重组载体pcDNA3.1.S2S/IFN α。然后用脂质体法转染VeroE6细胞。对重组载体进行了限制性酶切及PCR鉴定 ,证明连接正确 ;经间接免疫荧光检测证实该重组载体能在真核细胞中表达插入的外源性基因编码的融合蛋白。真核表达载体pcDNA3.1.S2S/IFN α的成功构建及在VeroE6细胞中的有效表达 。 展开更多
关键词 HBV preS2+S/INF-α融合基因 真核表达载体 乙型肝炎病毒 Α-干扰素 基因表达
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基于Monte Carlo模拟的Mixed Logit模型求解研究 被引量:1
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作者 张羽祥 赵胜川 《交通标准化》 2009年第1期112-115,共4页
Mixed Logit模型因能有效地避免其他离散选择模型的限制而被广泛地运用于交通领域,但由于它概率形式的非封闭性而导致了复杂的求解过程。从理论上证明利用Monte Carlo模拟方法求解Mixed Logit模型具有一定的合理性,并给出具体的求解步骤... Mixed Logit模型因能有效地避免其他离散选择模型的限制而被广泛地运用于交通领域,但由于它概率形式的非封闭性而导致了复杂的求解过程。从理论上证明利用Monte Carlo模拟方法求解Mixed Logit模型具有一定的合理性,并给出具体的求解步骤,可有效简化Mixed Logit模型的求解过程。 展开更多
关键词 mixed LOGIT模型 MONTE CARLO模拟 牛顿-拉普松算法
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一种基于停止-转发MIX的统计型攻击
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作者 徐红云 刘京 李孟杰 《小型微型计算机系统》 CSCD 北大核心 2010年第11期2217-2221,共5页
为了增强匿名系统的匿名性,更好地保护用户的通信隐私,基于停止-转发MIX提出一种新的统计型攻击算法.算法将攻击者的连续观察时间划分成t个周期,每个周期统计MIX节点输出信息包的接收者集合,称之为一个观察集合,获得t个观察集合后,采用... 为了增强匿名系统的匿名性,更好地保护用户的通信隐私,基于停止-转发MIX提出一种新的统计型攻击算法.算法将攻击者的连续观察时间划分成t个周期,每个周期统计MIX节点输出信息包的接收者集合,称之为一个观察集合,获得t个观察集合后,采用概率统计、集合运算等方法,确定目标发送者的接收者集合.指出采用填充包技术防御该攻击时,可以增加攻击所需的观察集合数,降低攻击的有效性. 展开更多
关键词 数据隐私 网络安全 匿名系统 停止-转发mix 统计型攻击
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Preβ-1高密度脂蛋白与心血管疾病关系的研究进展 被引量:1
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作者 李凤芹 聂宏刚 刘友斌 《中国心血管病研究》 CAS 2019年第1期5-8,12,共5页
动脉粥样硬化是心血管疾病重要的病理生理基础,延缓和防治动脉粥样硬化对于减少和降低心血管疾病的发病率及病死率具有重要意义。高密度脂蛋白(high density lipoprotein,HDL)通过参与介导胆固醇逆向转运(reverse cholesterol transport... 动脉粥样硬化是心血管疾病重要的病理生理基础,延缓和防治动脉粥样硬化对于减少和降低心血管疾病的发病率及病死率具有重要意义。高密度脂蛋白(high density lipoprotein,HDL)通过参与介导胆固醇逆向转运(reverse cholesterol transport,RCT)在抗动脉粥样硬化的形成和进展中发挥了重要作用。Preβ-1高密度脂蛋白(prebeta-1 high density lipoprotein,Preβ-1HDL)作为HDL的一种亚类,是外周细胞移出胆固醇的最初接受体,直接参与了RCT的起始步骤,并在随后的胆固醇酯化及转运中起着重要作用。本文就Preβ-1HDL的结构、代谢及其与心血管疾病的关系作一简要综述。 展开更多
关键词 preβ-1高密度脂蛋白 胆固醇逆转运 动脉粥样硬化 心血管疾病
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耦合pre-B tzinger复合体神经元中混合簇放电的多时间尺度动力学分析 被引量:4
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作者 马芬 段利霞 +2 位作者 梁桐桐 梁王娟 赵勇 《动力学与控制学报》 2020年第2期82-90,共9页
Pre-B tzinger复合体是新生哺乳动物呼吸节律起源的关键部位,是呼吸节律产生的中枢.本文以pre-B tzinger复合体中两个耦合的神经元为研究对象,并考虑钙离子动力学的耦合神经元模型.利用多时间尺度动力学、快慢尺度分解和分岔分析,研究... Pre-B tzinger复合体是新生哺乳动物呼吸节律起源的关键部位,是呼吸节律产生的中枢.本文以pre-B tzinger复合体中两个耦合的神经元为研究对象,并考虑钙离子动力学的耦合神经元模型.利用多时间尺度动力学、快慢尺度分解和分岔分析,研究混合簇同步放电模式及其产生机制,并研究了耦合神经元同相和反相簇放电类型及其同步转迁.结果表明钙离子的周期性波动对混合簇放电模式的产生有极大的影响,钙离子波动导致的时间尺度变化及分岔曲线相对位置的改变是混合簇放电产生的主要原因.本文的研究对认识pre-B tzinger中大规模网络的动力学有着重要的意义,为进一步探索呼吸节律的产生机制提供了一些有益的思考和见解. 展开更多
关键词 pre-B tzinger复合体 混合簇放电 快慢分析 多时间尺度 分岔
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The role of surface waves in the ocean mixed layer 被引量:13
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作者 QIAO Fangli YANG Yongzeng XIA Changshui YUAN Yeli 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2008年第3期30-37,共8页
Previously, most ocean circulation models have overlooked the role of the surface waves. As a result, these models have produced insufficient vertical mixing, with an under - prediction of the ,nixing layer (ML) dep... Previously, most ocean circulation models have overlooked the role of the surface waves. As a result, these models have produced insufficient vertical mixing, with an under - prediction of the ,nixing layer (ML) depth and an over - prediction of the sea surface temperature (SST), particularly during the summer season. As the ocean surface layer determines the lower boundary conditions of the atmosphere, this deficiency has severely limited the performance of the coupled ocean - atmospheric models and hence the climate studies. To overcome this shortcoming, a new parameterization for the wave effects in the ML model that will correct this systematic error of insufficient mixing. The new scheme has enabled the mixing layer to deepen, the surface excessive heating to be corrected, and an excellent agreement with observed global climatologic data. The study indicates that the surface waves are essential for ML formation, and that they are the primer drivers of the upper ocean dynamics; therefore, they are critical for climate studies. 展开更多
关键词 wave - induced mixing ocean circulation model mixing layer
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Numerical simulations of compressible mixing layers with a discontinuous Galerkin method 被引量:6
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作者 Xiao-Tian Shi Jun Chen +2 位作者 Wei-Tao Bi Chi-Wang Shu Zhen-Su She 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2011年第3期318-329,共12页
Discontinuous Galerkin(DG) method is known to have several advantages for flow simulations,in particular,in fiexible accuracy management and adaptability to mesh refinement. In the present work,the DG method is deve... Discontinuous Galerkin(DG) method is known to have several advantages for flow simulations,in particular,in fiexible accuracy management and adaptability to mesh refinement. In the present work,the DG method is developed for numerical simulations of both temporally and spatially developing mixing layers. For the temporally developing mixing layer,both the instantaneous fiow field and time evolution of momentum thickness agree very well with the previous results. Shocklets are observed at higher convective Mach numbers and the vortex paring manner is changed for high compressibility. For the spatially developing mixing layer,large-scale coherent structures and self-similar behavior for mean profiles are investigated. The instantaneous fiow field for a three-dimensional compressible mixing layer is also reported,which shows the development of largescale coherent structures in the streamwise direction. All numerical results suggest that the DG method is effective in performing accurate numerical simulations for compressible shear fiows. 展开更多
关键词 Compressible mixing layer - Discontinuous Galerkin method . Self-similarity . Coherent structure
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耦合pre-Bötzinger复合体中放电模式的动力学分析
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作者 齐会如 段利霞 徐浩 《动力学与控制学报》 2022年第2期22-35,共14页
混合簇放电是实验中发现的一种特殊的放电活动,其特点是在每个周期内有两种或多种不同类型的短簇放电模式,涉及极为复杂的动力学特征.运用相平面分析、快慢分析、ISI(峰峰间期)分岔序列、单参数和双参数分岔分析等方法,探究了pre-Bö... 混合簇放电是实验中发现的一种特殊的放电活动,其特点是在每个周期内有两种或多种不同类型的短簇放电模式,涉及极为复杂的动力学特征.运用相平面分析、快慢分析、ISI(峰峰间期)分岔序列、单参数和双参数分岔分析等方法,探究了pre-Bötzinger复合体中钙激活的非特异性阳离子电导(g_(CAN))和SERCA泵(V_(SERCA))对放电模式,特别是混合簇放电模式的影响.从动力学的角度给出了钙浓度呈周期波动时参数V_(SERCA)的取值范围,并解释了g_(CAN)对pre-Bötzinger复合体放电活动产生的影响及其转迁的机制.结果表明非特异性阳离子电导和V_(SERCA)会影响神经元的簇放电类型,且会引起混合簇放电的产生. 展开更多
关键词 pre-Bötzinger复合体 混合簇放电 分岔 快慢分析
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耦合Pre-Botzinger复合体神经元中混合簇放电模式的研究
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作者 王子剑 马芬 梁桐桐 《动力系统与控制》 2018年第3期154-161,共8页
Pre-B?tzinger复合体是新生哺乳动物呼吸节律起源的关键部位,是呼吸节律产生的中枢。本文以pre-B?tzinger复合体中两个耦合的神经元为研究对象,并考虑钙离子动力学的耦合神经元模型。利用快慢动力学和分岔分析,研究混合簇同步放电模式... Pre-B?tzinger复合体是新生哺乳动物呼吸节律起源的关键部位,是呼吸节律产生的中枢。本文以pre-B?tzinger复合体中两个耦合的神经元为研究对象,并考虑钙离子动力学的耦合神经元模型。利用快慢动力学和分岔分析,研究混合簇同步放电模式及其产生机制。结果表明钙离子的周期性波动对混合簇放电模式的产生有极大的影响,钙离子的波动及分岔曲线相对位置的改变是混合簇放电产生的主要原因. 展开更多
关键词 呼吸系统 pre-Botzinger复合体 混合簇放电 分岔
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Peierls stress for <110>{001} mixed dislocation in SrTiO_3 within framework of constrained path approximation
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作者 Xiaozhi Wu Shaofeng Wang RuipingLiu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2010年第3期425-432,共8页
The core structure of (110){001} mixed disloca- tion in perovskite SrTiO3 is investigated with the modified two-dimensional Peierls-Nabarro dislocation equation con- sidering the discreteness effect of crystals. The... The core structure of (110){001} mixed disloca- tion in perovskite SrTiO3 is investigated with the modified two-dimensional Peierls-Nabarro dislocation equation con- sidering the discreteness effect of crystals. The results show that the core structure of mixed dislocation is independent of the unstable energy in the (100) direction, but closely related to the unstable energy in the (110) direction which is the direction of total Burgers vector of mixed dislocation. Furthermore, the ratio of edge displacement to screw one nearly equals to the tangent of dislocation angle for differ- ent unstable energies in the (110) direction. Thus, the con- strained path approximation is effective for the (110){001} mixed dislocation in SrTiO3 and two-dimensional equation can degenerate into one-dimensional equation that is only related to the dislocation angle. The Peierls stress for (110) {001 } dislocations can be expediently obtained with the one-dimensional equation and the predictive values for edge, mixed and screw dislocations are 0.17, 0.22 and 0.46 GPa, respectively. 展开更多
关键词 Peierls stress - mixed dislocation SRTIO3
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Effect of Al Addition on Properties of Al_2O_3-SiC-C Dry Ramming Mixes for BF Trough
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作者 WANG Zhanmin WANG Qiang CAO Xiying 《China's Refractories》 CAS 2008年第3期1-5,共5页
Aluminium powders were introduced to Al2O3-SiC-C dry ramming mixes in order to improve sintering properties and oxidation resistance according to their service conditions and installation methods. Properties such as b... Aluminium powders were introduced to Al2O3-SiC-C dry ramming mixes in order to improve sintering properties and oxidation resistance according to their service conditions and installation methods. Properties such as bulk density, porosity, modulus of rupture, crushing strength and hot modulus of rupture as a function of aluminium addition were investigated in the present work. The microstructure and thermodynamics for the heat treated specimens were also analyzed. The results show that as aluminium addition increasing, the bulk density of the specimen treated at 220℃ tends to decrease and the apparent porosity increases, the strength of the specimens treated at 1100℃ and 1450℃ increases markedly, the bulk density tends to increase, apparent porosity and linear shrinkage decrease. The HMOR at 1400℃ is enhanced from 1.0 MPa to 3.5 MPa with 3% aluminium. Aluminium is served as sintering agent and anti-oxidant and it will react with CO and CO2 forming Al2O3 , which is helpful to enhance the strength, densify the structure and improve the overall properties. 展开更多
关键词 Al2O3 - SiC - C Dry ramming mixes BF Trough Oxidation resistance
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