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Fluidization characteristics of different sizes of quartz particles in the fluidized bed

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Petroleum Science 2016年第3期13卷 584-591页

作者： Zi-Jian Wang Jun Tang chun-xi lu State Key Laboratory of Heavy Oil Processing China University of Petroleum(Beijing)

Fluidization characteristics of quartz particles with different sizes are experimentally investigated in a fluidized bed with an inner diameter of 300 mm and height of 8250 *** show that the average solid holdup increases with the increase in superficial gas velocity and the decrease in initial solid holdup in the dense zone of the fluidized *** average cross-sectional solid holdup decreases with increasing bed height and superficial gas *** bed expansion coefficient increases with the increase in superficial gas velocity and the decrease in solid *** of average solid holdup,average cross-sectional solid holdup and bed expansion coefficient are also established and *** correlations can provide guidelines for better understanding of the fluidization characteristics.

关键词： Fluidization characteristic Solid holdup Axial average section solid holdup Bed expansion coefficient

Experimental study on the particle flow patterns in a cyclone dipleg with a trickle valve

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Petroleum Science 2020年第3期17卷 822-837页

作者： Chao-Yu Yan Guo-Gang Sun Jian-Yi Chen Yao-Dong Wei chun-xi lu Beijing Key Laboratory of Process Fluid Filtration and Separation College of Mechanical and Transportation EngineeringChina University of Petroleum-BeijingChangpingBeijing 102249People's Republic of China State Key Laboratory of Heavy Oil Processing College of Chemical Engineering and EnvironmentChina University of Petroleum-BeijingChangpingBeijing 102249People's Republic of China

An experimental apparatus including a dipleg and a trickle valve was established to simulate the operation of a suspended dipleg-trickle valve system of cyclone used in fluid catalytic cracking(FCC)*** flow regimes in the dipleg and the discharge modes in the trickle valve were studied by combining the observation of experimental phenomena with the analysis of transient pressure *** results show that the flow regimes in the dipleg have two types-the dilute–dense phase coexisting falling flow and the dilute falling ***,the trickle valve also has two discharge modes-the intermittent periodic dumping discharge and the continuous trickling *** power spectrum density of pressure fluctuation displays that the gas–solids flow in the dipleg-trickle valve system is characterized by a low-frequency *** coherence coefficient explains the origin and propagation of pressure fluctuation in the ***,a map describing the flow regimes and discharge modes related to the operation parameters was proposed,which can provide a helpful guidance for the operation of cyclone dipleg-trickle valve system in FCC unit.

关键词： Cyclone dipleg Trickle valve Flow regime Discharge mode Pressure fluctuation

Cross-subcarrier precoder design for massive MIMO-OFDM downlink with symplectic optimization

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Science China(Information Sciences) 2025年

作者： Yu-Xuan ZHANG An-An lu xiang-Gen xiA xi-Qi GAO National Mobile Communications Research Laboratory Southeast University Purple Mountain Laboratories Department of Electrical and Computer Engineering University of Delaware

We propose a cross-subcarrier precoder design(CSPD) for massive multiple-input multiple-output(MIMO) orthogonal frequency division multiplexing(OFDM) downlink. This work aims to significantly improve the channel estimation and signal detection performance by enhancing the smoothness of the frequency domain effective channel. This is accomplished by designing a few vectors known as the transform domain precoding vectors(TDPVs), which are then transformed into the frequency domain to generate the precoders for a set of subcarriers. To combat the effect of channel aging, the TDPVs are optimized under imperfect channel state information(CSI). The optimal precoder structure is derived by maximizing an upper bound of the ergodic weighted sum-rate(WSR) and utilizing the a posteriori beam-based statistical channel model(BSCM). To avoid the large-dimensional matrix inversion, we propose an algorithm with symplectic optimization. Simulation results indicate that the proposed cross-subcarrier precoder design significantly outperforms conventional methods.

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Deciphering Water Oxidation Catalysts:The Dominant Role of Surface Chemistry over Reconstruction Degree in Activity Promotion

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Nano-Micro Letters 2025年第3期17卷 340-354页

作者： Li An Jianyi Li Yuanmiao Sun Jiamin Zhu Justin Zhu Yeow Seow Hong Zhang Nan Zhang Pinxian xi * Zhichuan JXu chun‑Hua Yan State Key Laboratory of Applied Organic Chemistry Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu ProvinceFrontiers Science Center for Rare IsotopesCollege of Chemistry and Chemical EngineeringLanzhou UniversityLanzhou 730000People’s Republic of China School of Materials Science and Engineering Nanyang Technological UniversitySingapore 639798Singapore Faculty of Materials Science and Energy Engineering Institute of Technology for Carbon NeutralityShenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055People’s Republic of China Key Laboratory of Electromagnetic Materials and Devices National Center for International Research On Photoelectric and Energy MaterialsSchool of Materials and EnergyElectron Microscopy CenterYunnan UniversityKunming 650091People’s Republic of China State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization Baotou Research Institute of Rare EarthsBaotou 014030People’s Republic of China Beijing National Laboratory for Molecular Sciences State Key Laboratory of Rare Earth Materials Chemistry and ApplicationsPKU‑HKU Joint Laboratory in Rare Earth Materials and Bioinorganic ChemistryPeking UniversityBeijing 100871People’s Republic of China

Water splitting hinges crucially on the availability of electrocatalysts for the oxygen evolution *** surface reconstruction has been widely observed in perovskite catalysts,and the reconstruction degree has been often correlated with the activity ***,a systematic study on the roles of Fe substitution in activation of perovskite LaNiO_(3)is *** substituting Fe content influences both current change tendency and surface reconstruction ***_(0.9)Fe_(0.1)O_(3)is found exhibiting a volcano-peak intrinsic activity in both pristine and reconstructed among all substituted perovskites in the LaNi_(1-x)Fe_(x)O_(3)(x=0.00,0.10,0.25,0.50,0.75,1.00)*** reconstructed LaNi_(0.9)Fe_(0.1)O_(3)shows a higher intrinsic activity than most reported NiFe-based ***,density functional theory calculations reveal that Fe substitution can lower the O 2p level,which thus stabilize lattice oxygen in LaNi0.9Fe0.1O3 and ensure its long-term ***,it is vital interesting that activity of the reconstructed catalysts relied more on the surface chemistry rather than the reconstruction *** effect of Fe on the degree of surface reconstruction of the perovskite is decoupled from that on its activity enhancement after surface *** finding showcases the importance to customize the surface chemistry of reconstructed catalysts for water oxidation.

关键词： Oxygen evolution reaction Perovskite oxides Doping Activation and reconstruction

The Citron homology domain of MAP4Ks improves outcomes of traumatic brain injury

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Neural Regeneration Research 2025年第11期20卷 3233-3244页

作者： xiaoling Zhong Wenjiao Tai Meng-lu Liu Shuaipeng Ma Tianjin Shen Yuhua Zou chun-Li Zhang Department of Molecular Biology University of Texas Southwestern Medical CenterDallasTXUSA Hamon Center for Regenerative Science and Medicine University of Texas Southwestern Medical CenterDallasTXUSA Peter O’Donnell Jr.Brain Institute University of Texas Southwestern Medical CenterDallasTXUSA

The mitogen-activated protein kinase kinase kinase kinases(MAP4Ks)signaling pathway plays a pivotal role in axonal regrowth and neuronal degeneration following *** targeting this pathway is beneficial to brain injury remains *** this study,we showed that adeno-associated virus-delivery of the Citron homology domain of MAP4Ks effectively reduces traumatic brain injury-induced reactive gliosis,tauopathy,lesion size,and behavioral *** inhibition of MAP4Ks replicated the ameliorative effects observed with expression of the Citron homology ***,the Citron homology domain acted as a dominant-negative mutant,impeding MAP4K-mediated phosphorylation of the dishevelled proteins and thereby controlling the Wnt/β-catenin *** findings implicate a therapeutic potential of targeting MAP4Ks to alleviate the detrimental effects of traumatic brain injury.

关键词： adeno-associated virus Citron homology Citron homology domain gene therapy mitogen-activated protein kinase kinase kinase kinases traumatic brain injury

Ni-catalyzed cross-electrophile alkyl-alkyl coupling reactions

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Science China Chemistry 2025年

作者： Li-Xu You Lan Tian chun-Ling Guo Shun-xi Li Yu-Cheng Liu Yu-Long Li Wei Shu College of Chemistry and Environmental Engineering Key Laboratory of Green Catalysis of Higher Education Institutes of Sichuan Sichuan University of Science and Engineering Guangming Advanced Research Institute Shenzhen Grubbs Institute Department of Chemistry and Guangdong Provincial Key Laboratory of Catalysis Southern University of Science and Technology

Introducing saturated carbon-carbon bonds into organic molecules significantly increases the three-dimensional configuration,thus altering the physical and chemical properties as well as the functions of molecules. Transition-metal-catalyzed carboncarbon cross-couplings represent one of the most straightforward, efficient and modular alternatives to build saturation in a single step. However, the efficient construction of alkyl-alkyl bonds remains a formidable challenge due to the precise manipulation of multiple alkyl metallic intermediates as well as associated competitive side reactions and selectivity control. Over the past years, Ni-catalyzed cross-coupling under reductive conditions has gained more and more attention for alkyl-alkyl crosscoupling partially attributing to the low-valent state of metal centers under reducing conditions, which suppresses the competitive β-hydride elimination process, thus facilitating the formation of alkyl-alkyl bonds. In this review, the initiative and progress of Ni-catalyzed cross-electrophile alkyl-alkyl cross-coupling, including the efforts in racemic and enantioselective formation of alkyl-alkyl bonds, have been summarized and discussed. Moreover, the challenges and further opportunities in this area have also been discussed.

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托氟啶固体脂质纳米粒的制备及其小鼠体内药动学

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中国新药与临床杂志 2009年第3期28卷 185-190页

作者：白帆刘春喜戴璐萍刘亮张娜山东大学药学院山东济南250012

目的制备托氟啶(TFu)固体脂质纳米粒(TFu-SLN),并对其进行理化性质评价和小鼠体内药动学研究。方法HPLC法测定体内外TFu的含量;用薄膜分散法制备TFu-SLN;透射电镜观察纳米粒形态;激光粒度分析仪测定其粒径、粒度分布和zeta电位;以TFu50... 详细信息

目的制备托氟啶(TFu)固体脂质纳米粒(TFu-SLN),并对其进行理化性质评价和小鼠体内药动学研究。方法HPLC法测定体内外TFu的含量;用薄膜分散法制备TFu-SLN;透射电镜观察纳米粒形态;激光粒度分析仪测定其粒径、粒度分布和zeta电位;以TFu50%乙腈溶液为对照,采用动态膜透析法分别考察TFu-SLN在磷酸盐缓冲液(pH7.4)、人工胃液(pH1.2)、人工肠液(pH6.8)以及人工胃液2h后转入人工肠液中至48h的体外释药情况;以TFu水混悬液组为对照,考察小鼠口服TFu-SLN后药动学性质。结果所制备的TFu-SLN呈球形或类球形,平均粒径为(156.5±s0.5)nm,zeta电位为(-30±4)mV,平均包封率为(84±4)%,平均载药量为(2.1±0.9)%。体外释放结果表明将TFu制成固体脂质纳米粒可明显延缓药物释放的时间。小鼠口服TFu-SLN相对于口服TFu水混悬液的生物利用度为209%。结论薄膜分散法制备的TFu固体脂质纳米粒包封率较高,具有一定的缓释能力,生物利用度较高,对促进难溶性药物口服具有一定意义。

关键词：抗肿瘤药药动学生物利用度托氟啶固体脂质纳米粒薄膜分散法

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北京和东北地区雷暴与太阳活动的关系

空间科学学报 1986年第1期 52-59页

作者：庄洪春吕锡从中国科学院空间物理研究所中国科学院空间物理研究所

太阳活动对于大气电性能可能会产生影响,而大气电性能在雷暴形成过程中可能会起着重要作用.因此,太阳活动对于大气电性能的影响,最终将有可能影响到雷暴的形成.本文用1957年到1978年北京地区和东北地区的10个气象站的13000多个雷暴资料... 详细信息

太阳活动对于大气电性能可能会产生影响,而大气电性能在雷暴形成过程中可能会起着重要作用.因此,太阳活动对于大气电性能的影响,最终将有可能影响到雷暴的形成.本文用1957年到1978年北京地区和东北地区的10个气象站的13000多个雷暴资料,用时序迭加法分析了雷暴数与太阳磁扇形界面通过、太阳耀斑及太阳黑子11年周期变化等的关系.结果表明,有些年分的雷暴数当行星际磁场方向由指向太阳变为离开太阳的磁扇形界面扫过地球时有相关影响,在界面通过前后3天内或7天后雷暴数明显增大.从季节来看,上半年的界面通过比下半年的界面通过对雷暴的影响大.在各种太阳耀斑分类统计分析中,看到出现在日面上西区特别是西一区(0°-30°)的耀斑对雷暴的影响显著.雷暴数与太阳黑子11年周期变化则没有很显著的相关关系.

关键词：太阳活动大气电行星际磁场磁扇形周期变化日面气象台站地球时扫过统计分析

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智能语音导游器的设计与实现

信息技术与信息化 2004年第4期 21-23页

作者：唐启鹏周求湛杨熙春卢昊吉林大学通信学院长春130022

本文提出了一种智能语音导游器的设计方案。相对于其他导游器 ,该导游器改善了已有导游器不智能 ,操作不方便 ,语音存储量小等问题。阐述了其工作原理 ,详细介绍了各个模块的组成与实现 ,并给出了系统工作的软件框图和各个模块的硬件连... 详细信息

本文提出了一种智能语音导游器的设计方案。相对于其他导游器 ,该导游器改善了已有导游器不智能 ,操作不方便 ,语音存储量小等问题。阐述了其工作原理 ,详细介绍了各个模块的组成与实现 ,并给出了系统工作的软件框图和各个模块的硬件连线图。

关键词：智能语音导游器条形码 MP3 FLASH芯片