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Effects of zinc on χ-Fe_(5)C_(2) for carbon dioxide hydrogenation to olefins:Insights from experimental and density function theory calculations

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Chinese Journal of Chemical Engineering 2023年第2期54卷 206-214页

作者： Xianglin Liu Minjie Xu Chenxi Cao zixu yang Jing Xu State Key Laboratory of Chemical Engineering East China University of Science and TechnologyShanghai 200237China Maoming Branch R&D Institute SINOPECMaoming 525000China Key Laboratory of Smart Manufacturing in Energy Chemical Process Ministry of EducationEast China University of Science and TechnologyShanghai 200237China

Production of light olefins from CO_(2), the primary greenhouse gases, is of great importance to mitigate the adverse effects of CO_(2) emission on environment and to supply the value-added products from nonpetroleum resource. However, development of robust catalyst with controllable selectivity and stability remains a challenge. Herein, we report that Zn-promoted Fe catalyst can boost the stable and selective production of light olefins from CO_(2). Specifically, the Zn-promoted Fe exhibits a highly stable activity and olefin selectivity over 200 h time-on-stream compared to the unpromoted Fe catalyst, primarily owing to the preservation of active χ-Fe_(5)C_(2) phase. Structural characterizations of the spent catalysts suggest that Zn substantially regulates the content of iron carbide on the surface and suppresses the reoxidation of bulk iron carbide during the reaction. DFT calculations confirm that adsorption of surface carbon atoms and graphene-like carbonaceous species are not thermochemically favored on Zn-promoted Fe catalyst. Carbon deposition by CAC coupling reactions of two surface carbon atoms and dehydrogenation of CH intermediate are also inhibited. Furthermore, the effects of Zn on antioxidation of iron carbide were also investigated. Zn favored the hydrogenation of surface adsorbed oxygen atoms to H_(2)O and the desorption of H_(2)O, which reduces the possibility of surface carbide being oxidized by the chemisorbed oxygen.

关键词： Reaction engineering χ-Fe_(5)C_(2) Zn promoter Carbon dioxide Hydrogenation Density function theory

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吉林大学学报（医学版） 2024年第1期50卷 198-207页

作者：杨紫煦苏畅王波元刘冲李明贺吉林大学口腔医院口腔颌面外科吉林长春130021 吉林大学第二医院口腔科吉林长春130022

目的:筛选头颈部鳞状细胞癌(HNSCC)差异预后乳酸代谢相关基因(LRGs),构建HNSCC的LRGs预后模型,并阐明其潜在的作用机制。方法 :由癌症基因组图谱(TCGA)数据库和基因表达综合(GEO)数据库获取HNSCC基因表达及临床数据,由GeneCards数据库... 详细信息

目的:筛选头颈部鳞状细胞癌(HNSCC)差异预后乳酸代谢相关基因(LRGs),构建HNSCC的LRGs预后模型,并阐明其潜在的作用机制。方法 :由癌症基因组图谱(TCGA)数据库和基因表达综合(GEO)数据库获取HNSCC基因表达及临床数据,由GeneCards数据库中获取LRGs,采用R软件筛选HNSCC的LRGs。采用单因素Cox回归分析得到预后相关基因,基于预后相关LRGs鉴定出2种不同亚型,采用Kaplan-Meier (K-M)曲线分析比较2组患者预后,采用CIBERSORT算法进行2组患者间的免疫相关分析。采用多因素Cox回归分析和LASSO回归分析构建预后模型,采用受试者工作特征曲线(ROC)和K-M生存曲线评估LRGs与HNSCC患者生存和预后的关系。采用GSE27020、GSE41613和GSE65858数据集验证预后模型。基于风险评分进行分组,并进行免疫相关分析和肿瘤相关评分分析。结果:通过TCGA数据库从HNSCC样本中差异分析筛选出1 196个LRGs,单因素Cox回归分析筛选出27个差异表达基因(DEGs)与HNSCC患者预后相关,根据预后相关基因鉴定出2种不同的LRGs亚型(分组1和分组2),K-M生存曲线显示分组2患者总生存期(OS)明显高于分组1,分组2患者免疫细胞浸润水平明显高于分组1。多因素Cox回归分析和LASSO回归分析筛选出9个LRGs,包括次黄嘌呤磷酸核糖基转移酶1 (HPRT1)、淀粉样蛋白前体蛋白(APP)、糖原磷酸化酶(PYGL)、尿激酶型纤溶酶原激活物(PLAU)、大麻素受体2(CNR2)、斯钙素2(STC2)、核苷酸结合寡聚化结构域样受体1 (NLRP1)、整合素连接激酶(ILK)和叉头框蛋白B1 (FOXB1),构建预后模型,K-M曲线和ROC曲线显示上述9个基因表达水平与HNSCC患者生存和预后有关联,且均具有良好的1、 2和3年生存预测作用,ROC曲线下面积(AUC)均大于0.650,且预后模型的预后预测作用在GSE27020、GSE41613和GSE65858数据集中得到验证。根据风险评分分类的患者具有可区分的免疫状态。结论:基于生物信息学方法筛选出的HNSCC差异表达LRGs与HNSCC患者生存和预后有关联,由9个LRGs构建的预后模型可预测HNSCC患者的生存情况和治疗反应。

关键词：头颈部鳞状细胞癌乳酸代谢免疫浸润生物信息学 LASSO回归分析

State Estimation of Drive-by-Wire Chassis Vehicle Based on Dual Unscented Particle Filter Algorithm

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 99-113页

作者： zixu Wang Chaoning Chen Quan Jiang Hongyu Zheng Chuyo Kaku State Key Laboratory of Automotive Simulation and Control Jilin UniversityChangchun 130022China Jiangsu Chaoli Electric Co.Ltd. Zhenjiang 212321China

Accurate vehicle dynamic information plays an important role in vehicle driving ***,due to the characteristics of high mobility and multiple controllable degrees of freedom of drive-by-wire chassis vehicles,the current mature application of traditional vehicle state estimation algorithms can not meet the requirements of drive-by-wire chassis vehicle state *** paper proposes a state estimation method for drive-by-wire chassis vehicle based on the dual unscented particle filter algorithm,which make full use of the known advantages of the four-wheel drive torque and steer angle parameters of the drive-by-wire chassis *** the dual unscented particle filter algorithm,two unscented particle filter transfer information to each other,observe the vehicle state information and the tire force parameter information of the four wheels respectively,which reduce the influence of parameter uncertainty and model parameter changes on the estimation accuracy during *** performance with the dual unscented particle filter algorithm,which is analyzed in terms of the time-average square error,is superior of the unscented Kalman filter *** effectiveness of the algorithm is further verified by driving simulator *** this paper,a vehicle state estimator based on dual unscented particle filter algorithm was proposed for the first time to improve the estimation accuracy of vehicle parameters and states.

关键词： Drive-by-wire chassis vehicle Vehicle state estimation Dual unscented particle filter Tire force estimation Unscented particle filter

Reheat effect on the improvement in efficiency of the turbine driven by pulse detonation

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Defence Technology（防务技术） 2024年第1期31卷 200-210页

作者： Junyu Liu Zhiwu Wang zixu Zhang Junlin Li Weifeng Qin Jingjing Huang School of Power and Energy Northwestern Polytechnical UniversityXi’an 710072China Shenzhen Research Institute of Northwestern Polytechnical University Shenzhen 518057China Mechanical Engineering College Xi’an Shiyou UniversityXi’an 710065China

Due to the strong unsteadiness of pulse detonation,large flow losses are generated when the detonation wave interacts with the turbine blades,resulting in low turbine *** that the flow losses are dissipated into the gas as heat energy,some of them can be recycled during the expansion process in subsequent stages by the reheat effect,which should be helpful to improve the detonationdriven turbine *** this into account,this paper developed a numerical model of the detonation chamber coupled with a two-stage axial turbine,and a stoichiometric hydrogen-air mixture was *** improvement in turbine efficiency attributable to the reheat effect was calculated by comparing the average efficiency of the stages with the efficiency of the two-stage *** research indicated that the first stage was critical in suppressing the flow unsteadiness caused by pulse detonation,which stabilized the intake condition of the second stage and consequently allowed much of the flow losses from the first stage to be recycled,so that the efficiency of the two-stage turbine was *** a 95%confidence level,the efficiency improvement was stable at 4.5%—5.3%,demonstrating that the reheat effect is significant in improving the efficiency of the detonation-driven turbine.

关键词： Pulse detonation turbine engine Hydrogen detonation Turbine efficiency Reheat effect Multi-cycle detonation

Manipulation of the PdAu-PdAuO_(x)interface on Pd-Au bimetallic catalysts for the direct synthesis of hydrogen peroxide

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Chinese Chemical Letters 2023年第11期34卷 195-201页

作者： Jixuan Zhang Pengfei Tian Aihao Xu Like Ouyang zixu yang Jing Xu State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China Key Laboratory of Pressure Systems and Safety Ministry of EducationEast China University of Science and TechnologyShanghai 200237China Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology School of Chemistry and Chemical EngineeringGuangxi UniversityNanning 530004China College of Chemical Engineering Sichuan UniversityChengdu 610065China

Direct synthesis of H_(2)O_(2)from H_(2) and O_(2)via heterogeneous catalysis is an environmentally friendly and atomically economic alternative to the traditional anthraquinone oxidation(AO)*** the electronic and geometric structures of the active metals to break the current limitations of hydrogenation rate and H_(2)O_(2)selectivity is a promising and challenging *** this study,a series of Pd-Au bimetallic catalysts supported on TiO_(2)with a metal loading of 3.0 wt%and a constant Pd/Au molar ratio(Pd:Au=2:1)were *** catalysts were reduced in H_(2) at different temperatures(473,573 and 673 K),and their catalytic activity for the direct H_(2)O_(2)synthesis were evaluated at 283 K and 0.1MPa.H_(2) reduced Pd-Au catalysts exhibited superior performance in direct H_(2)O_(2)*** maximum H_(2)O_(2)selectivity of 87.7%and H_(2)O_(2)yield of 3116.4 mmol h^(−1) gPd^(−1) were achieved over the Pd_(2.0)Au_(1.0)-573 catalyst with a H_(2) conversion of 12.8%.The tailored local chemical environment caused by H_(2) reduction creates a balanced ratio of Pd0 and PdO_(x) sites,thus improving the selectivity towards H_(2)O_(2).This work developed an effective strategy for fabrication of highly active and stable Pd-based H_(2)O_(2)synthesis catalysts with high H_(2)O_(2)yield.

关键词： H_(2)O_(2)synthesis Bimetallic catalysts Palladium particle size Pd^(0)/Pd^(2+)ratio Structure-performance relationship

Representation of the Stratospheric Circulation in CRA-40 Reanalysis:The Arctic Polar Vortex and the Quasi-Biennial Oscillation

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Advances in Atmospheric Sciences 2024年第5期41卷 894-914页

作者： zixu WANG Shirui YAN Jinggao HU Jiechun DENG Rongcai REN Jian RAO Key Laboratory of Meteorological Disaster Ministry of Education(KLME)Joint International Research Laboratory of Climate and Environment Change(ILCEC)Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)Nanjing University of Information Science&TechnologyNanjing 210044China Key Laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric SciencesLanzhou UniversityLanzhou 730000China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

The representation of the Arctic stratospheric circulation and the quasi-biennial oscillation(QBO)during the period 1981–2019 in a 40-yr Chinese global reanalysis dataset(CRA-40)is evaluated by comparing two widely used reanalysis datasets,ERA-5 and ***-40 demonstrates a comparable performance with ERA-5 and MERRA-2 in characterizing the winter and spring circulation in the lower and middle Arctic ***,differences in the climatological polar-mean temperature and polar night jet among the three reanalyses are within±0.5 K and±0.5 m s^(–1),*** onset dates of the stratospheric sudden warming and stratospheric final warming events at 10 hPa in CRA-40,together with the dynamics and circulation anomalies during the onset process of warming events,are nearly identical to the other two reanalyses with slight *** contrast,the CRA-40 dataset demonstrates a deteriorated performance in describing the QBO below 10 hPa compared to the other two reanalysis products,manifested by the larger easterly biases of the QBO index,the remarkably weaker amplitude of the QBO,and the weaker wavelet power of the QBO *** pronounced biases are mainly concentrated in the period 1981–98 and largely reduced by at least 39%in 1999–***,particular caution is needed in studying the QBO based on *** three reanalyses exhibit greater disagreement in the upper stratosphere compared to the lower and middle stratosphere for both the polar region and the tropics.

关键词： CRA-40 ERA-5 MERRA-2 Arctic stratosphere the QBO

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采用表示分离自编码器的任意说话人语音转换

通信学报 2024年第2期45卷 162-172页

作者：简志华章子旭杭州电子科技大学通信工程学院浙江杭州310018

针对非平行语料库下任意说话人之间的语音转换存在语言内容信息和说话人个性特征难以分离,从而导致语音转换的性能不佳的问题,提出了一种采用表示分离自编码器的语音转换方法RSAE-VC。该方法将语音信号的说话人个性特征视为时不变,而将... 详细信息

针对非平行语料库下任意说话人之间的语音转换存在语言内容信息和说话人个性特征难以分离,从而导致语音转换的性能不佳的问题,提出了一种采用表示分离自编码器的语音转换方法RSAE-VC。该方法将语音信号的说话人个性特征视为时不变,而将内容信息视为时变,利用编码器中的实例归一化和激活引导层将两者进行分离,再由解码器将源语音的内容信息与目标语音的个性特征进行合成,从而生成转换后的语音。实验结果表明,RSAE-VC在梅尔倒谱距离上比现有的AGAIN-VC转换方法平均降低了3.11%,在基音频率均方根误差上降低了2.41%,MOS分和ABX值分别提升了5.22%和8.45%。RSAE-VC方法通过自内容损失进行约束使语音更好地保留内容信息,通过自说话人损失将说话人个性特征更好地从语音中分离,可以确保说话人个性特征尽少地遗留在内容信息中,从而提高语音转换性能。

关键词：语音转换表示分离自适应实例归一化自内容损失自说话人损失

Fresh-Keeping Decision and Coordination of Fresh Agricultural Product Supply Chain Considering Carbon Cap-and-Trade under Different Dominance

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Journal of Systems Science and Systems Engineering 2024年第1期33卷 30-51页

作者： yang yang Guanxin Yao China Institute for Agricultural Equipment Industrial Development Jiangsu UniversityZhenjiang212013China Jiangsu Modern Logistics Research Base Yangzhou UniversityYangzhou225009China

In the context of low carbon,this paper discussed the impact of the carbon cap-and-trade policy on the fresh-keeping decision-making of two-echelon fresh agricultural product supply chains under different dominance,and designed cost-sharing contracts to coordinate the supply chain of fresh agricultural products dominated by suppliers and retailers *** results showed that:dominance has no effect on the fresh-keeping decision and total revenue of fresh agricultural product supply chain,but it affects the internal income distribution,and dominance does not always bring more benefits;the implementation of carbon cap-and-trade reduces the fresh-keeping decision-making of fresh agricultural products supply chain and reduces the free-rider income of followers;the role of higher carbon trading price is twofold,which not only brings about the speculation of leading enterprises,but also promotes the application of low-carbon technologies;consumers’high preference for freshness,low-cost and high-efficiency low-carbon technology are all conducive to improving the fresh-keeping efforts and benefits of the supply chain;cost-sharing contracts can coordinate the supply chain of fresh agricultural products.

关键词： Dominant power carbon cap-and-trade policy fresh agricultural product supply chain fresh-keeping decision-making

Overview of radar detection methods for low altitude targets in marine environments

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Journal of Systems Engineering and Electronics 2024年第1期35卷 1-13页

作者： yang Yong yang Boyu School of Electronic Science National University of Defense TechnologyChangsha 410073China

In this paper,a comprehensive overview of radar detection methods for low-altitude targets in maritime environments is presented,focusing on the challenges posed by sea clutter and multipath *** performance of the radar detection methods under sea clutter,multipath,and combined conditions is categorized and summarized,and future research directions are outlined to enhance radar detection performance for low-altitude targets in maritime environments.

关键词： radar sea clutter multipath scattering detection low altitude target