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膦基复合催化剂高效催化二氧化碳合成环状碳酸酯 被引量:1
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作者 张贺明 孟婵 +2 位作者 董丽 苏倩 成卫国 《过程工程学报》 CAS CSCD 北大核心 2023年第7期987-994,共8页
二氧化碳(CO_(2))既是造成温室效应的主要气体,也是一种重要的C1资源,CO_(2)资源化利用是全球战略目标和研究热点,以CO_(2)与环氧化合物为原料合成环状碳酸酯是其高效高值化利用的主要途径。为解决以往催化剂体系存在的催化剂稳定性差... 二氧化碳(CO_(2))既是造成温室效应的主要气体,也是一种重要的C1资源,CO_(2)资源化利用是全球战略目标和研究热点,以CO_(2)与环氧化合物为原料合成环状碳酸酯是其高效高值化利用的主要途径。为解决以往催化剂体系存在的催化剂稳定性差、催化活性低、催化剂制备复杂等问题,本研究以高稳定性的氧膦化合物与过渡金属盐进行复配,通过调控过渡金属盐和氧膦化合物的比例,形成不同配比的二元复合催化体系,优选了最佳过渡金属盐和最佳比例(三丁基氧膦与溴化锌摩尔比为2:1,即[2Bu3PO-ZnBr2]),考察了催化剂用量、CO_(2)压力、反应时间、反应温度的影响,在最佳反应条件下(130℃,3 h,3 MPa),环氧丙烷(PO)的转化率可达92%。通过相关表征揭示了膦基复合催化体系与反应物之间的相互作用,提出了可能的催化机理。[2Bu3PO-ZnBr2]催化体系在循环使用5次后,依然能够保持高催化活性。本研究提出的膦基二元复合催化体系可为催化剂设计和CO_(2)利用提供思路。 展开更多
关键词 二氧化碳 环加成反应 环状碳酸酯
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Interaction Between Memory Load and Experimental Design on Brain Connectivity and Network Topology 被引量:1
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作者 heming zhang Xin Di +3 位作者 Bart Rypma Hang Yang Chun Meng Bharat Biswal 《Neuroscience Bulletin》 SCIE CAS CSCD 2023年第4期631-644,共14页
The conventional approach to investigating functional connectivity in the block-designed study usually concatenates task blocks or employs residuals of task activation.While providing many insights into brain function... The conventional approach to investigating functional connectivity in the block-designed study usually concatenates task blocks or employs residuals of task activation.While providing many insights into brain functions,the block design adds more manipulation in functional network analysis that may reduce the purity of the blood oxygenation level-dependent signal.Recent studies utilized one single long run for task trials of the same condition,the so-called continuous design,to investigate functional connectivity based on task functional magnetic resonance imaging.Continuous brain activities associated with the single-task condition can be directly utilized for task-related functional connectivity assessment,which has been examined for working memory,sensory,motor,and semantic task experiments in previous research.But it remains unclear how the block and continuous design influence the assessment of task-related functional connectivity networks.This study aimed to disentangle the separable effects of block/continuous design and working memory load on task-related functional connectivity networks,by using repeated-measures analysis of variance.Across 50 young healthy adults,behavioral results of accuracy and reaction time showed a significant main effect of design as well as interaction between design and load.Imaging results revealed that the cingulo-opercular,fronto-parietal,and default model networks were associated with not only task activation,but significant main effects of design and load as well as their interaction on intra-and inter-network functional connectivity and global network topology.Moreover,a significant behavior-brain association was identified for the continuous design.This work has extended the evidence that continuous design can be used to study task-related functional connectivity and subtle brain-behavioral relationships. 展开更多
关键词 Working memory Functional connectivity Network topology Block design Continuous design Memory load
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Facial Expression Enhances Emotion Perception Compared to Vocal Prosody:Behavioral and fMRI Studies 被引量:1
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作者 heming zhang Xuhai Chen +4 位作者 Shengdong Chen Yansong Li Changming Chen Quanshan Long Jiajin Yuan 《Neuroscience Bulletin》 SCIE CAS CSCD 2018年第5期801-815,共15页
Facial and vocal expressions are essential modalities mediating the perception of emotion and social communication.Nonetheless,currently little is known about how emotion perception and its neural substrates differ ac... Facial and vocal expressions are essential modalities mediating the perception of emotion and social communication.Nonetheless,currently little is known about how emotion perception and its neural substrates differ across facial expression and vocal prosody.To clarify this issue,functional MRI scans were acquired in Study 1,in which participants were asked to discriminate the valence of emotional expression(angry,happy or neutral)from facial,vocal,or bimodal stimuli.In Study 2,we used an affective priming task(unimodal materials as primers and bimodal materials as target)and participants were asked to rate the intensity,valence,and arousal of the targets.Study 1 showed higher accuracy and shorter response latencies in the facial than in the vocal modality for a happy expression.Whole-brain analysis showed enhanced activation during facial compared to vocal emotions in the inferior temporal-occipital regions.Region of interest analysis showed a higher percentage signal change for facial than for vocal anger in the superior temporal sulcus.Study 2 showed that facial relative to vocal priming of anger had a greater influence on perceived emotion for bimodal targets,irrespective of the target valence.These findings suggest that facial expression is associated with enhanced emotion perception compared to equivalent vocal prosodies. 展开更多
关键词 FMRI Emotion perception Facial expres-sion Vocal prosody MODALITY
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Insight into the CO2 photoreduction mechanism over 9-hydroxyphenal-1-one(HPHN) carbon quantum dots
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作者 Zhengyan Zhao heming zhang +4 位作者 Xuedan Song Yantao Shi Duanhui Si Hongjiang Li Ce Hao 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2021年第1期269-276,I0009,共9页
Converting CO2 to carbon-containing fuels is an effective approach to relieving energy shortages.Carbon quantum dots(CQDs) have shown distinct properties and attracted tremendous interest in CO2 reduction.Herein,we re... Converting CO2 to carbon-containing fuels is an effective approach to relieving energy shortages.Carbon quantum dots(CQDs) have shown distinct properties and attracted tremendous interest in CO2 reduction.Herein,we report a joint experimental-computational mechanistic study of photoreduction CO2 to CO on the model catalyst 9-hydroxyphenal-1-one(HPHN) CQDs with known structure.Our theoretical calculations reveal that the rate-determining step is COOH·formation,which is closely related to the proton and electron transfer induced by hydrogen bonding in the excited state.According to the calculated volcano plot,the solution we proposed is addition Zn^(2+) ions.The active center changed from the hydroxyl oxygen atom to the Zn atom and the barrier of the COOH·formation step is noticeably decreased when Zn^(2+) ions are added.It is further confirmed by the experimental data that the activity of CO2 reduction increases 2.9 times when Zn^(2+) ions are added. 展开更多
关键词 CO2 reduction DFT study Reaction mechanism Hydrogen bonding Excited state
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Frontier molecular orbital weighted model based networks for revealing organic delayed fluorescence efficiency
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作者 Zhaoming He Hai Bi +3 位作者 Baoyan Liang Zhiqiang Li heming zhang Yue Wang 《Light: Science & Applications》 2025年第3期800-810,共11页
Free of noble-metal and high in unit internal quantum efficiency of electroluminescence,organic molecules with thermally activated delayed fluorescence(TADF)features pose the potential to substitute metal-based phosph... Free of noble-metal and high in unit internal quantum efficiency of electroluminescence,organic molecules with thermally activated delayed fluorescence(TADF)features pose the potential to substitute metal-based phosphorescence materials and serve as the new-generation emitters for the mass production of organic light emitting diodes(OLEDs)display.Predicting the function of TADF emitters beyond classic chemical synthesis and material characterization experiments remains a great challenge.The advances in deep learning(DL)based artificial intelligence(Al)offer an exciting opportunity for screening high-performance TADF materials through efficiency evaluation.However,data-driven material screening approaches with the capacity to access the excited state properties of TADF emitters remain extremely difficult and largely unaddressed.nspired by the fundamental principle that the excited state properties of TADF molecules are strongly dependent on their D-A geometric and electronic structures,we developed the Electronic Structure-lnfused Network(ESIN)for TADF emitter screening.Designed with capacities of accurate prediction of the photoluminescence quantum yields(PLQYs)of TADF molecules based on elemental molecular geometry and orbital information and integrated with frontier molecular orbitals(FMOs)weightbased representation and modeling features,ESIN is a promising interpretable tool for emission efficiency evaluation and moleculardesign of TADF emitters. 展开更多
关键词 chemical synthesis NETWORKS material characterization experiments weighted model thermally activated delayed fluorescence tadf features electroluminescenceorganic molecules organic light emitting diodes oleds displaypredicting deep l
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BOM-BASED DESIGN KNOWLEDGE REPRESENTATION AND REASONING FOR COLLABORATIVE PRODUCT DEVELOPMENT 被引量:5
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作者 Gongzhuang Peng Huachao Mao +1 位作者 Hongwei Wang heming zhang 《Journal of Systems Science and Systems Engineering》 SCIE EI CSCD 2016年第2期159-176,共18页
Modem product development becomes increasingly collaborative and integrated, which raises the need for effectively and efficiently sharing and re-using design knowledge in a distributed and collaborative environment. ... Modem product development becomes increasingly collaborative and integrated, which raises the need for effectively and efficiently sharing and re-using design knowledge in a distributed and collaborative environment. To address this need, a framework is developed in this research to support design knowledge representation, retrieval, reasoning and fusion, which takes account of structural, functional and behavioral data, various design attributes and knowledge reasoning cases. Specifically, a multi-level knowledge representation based on the Base Object Model (BOM) is proposed to enable knowledge sharing using Web services technologies. On this basis, a multi-level knowledge reuse method is developed to support the retrieval, matching and assembly of knowledge records. Due to the tree structure of BOM, both depth-first and breadth-first searching strategies are employed in the retrieval algorithm while a novel measure is proposed to evaluate similarity. Moreover, a method based on the D-S evidence theory is developed to enable knowledge fusion and thus support effective decision-making. The framework has been implemented and integrated into an HLA-based simulation platform on which the development of a missile simulation example is conducted. It is demonstrated in the case study that the proposed framework and methods are useful and effective for design knowledge representation and reuse. 展开更多
关键词 Complex product development multi-level knowledge reuse knowledge fusion Base Object Model D-S evidence theory
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Chromosome-scale genomes provide new insights into subspecies divergence and evolutionary characteristics of the giant panda 被引量:2
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作者 Xuanmin Guang Tianming Lan +28 位作者 Qiu-Hong Wan Yan Huang Hong Li Mingchun zhang Rengui Li Zhizhong zhang Yinghu Lei Ling zhang heming zhang Desheng Li Xiaoping Li Haimeng Li Yan Xu Maiju Qiao Daifu Wu Keyi Tang Pengpeng Zhao Jian-Qing Lin Sunil KumarSahu Qiqi Liang Wenkai Jiang Danhui zhang Xun Xu Xin Liu Michael Lisby Huanming Yang Karsten Kristiansen Huan Liu Sheng-Guo Fang 《Science Bulletin》 SCIE EI CSCD 2021年第19期2002-2013,M0004,共13页
Extant giant pandas are divided into Sichuan and Qinling subspecies.The giant panda has many speciesspecific characteristics,including comparatively small organs for body size,small genitalia of male individuals,and l... Extant giant pandas are divided into Sichuan and Qinling subspecies.The giant panda has many speciesspecific characteristics,including comparatively small organs for body size,small genitalia of male individuals,and low reproduction.Here,we report the most contiguous,high-quality chromosomelevel genomes of two extant giant panda subspecies to date,with the first genome assembly of the Qinling subspecies.Compared with the previously assembled giant panda genomes based on short reads,our two assembled genomes increased contiguity over 200-fold at the contig level.Additional sequencing of 25 individuals dated the divergence of the Sichuan and Qinling subspecies into two distinct clusters from 10,000 to 12,000 years ago.Comparative genomic analyses identified the loss of regulatory elements in the dachshund family transcription factor 2(DACH2)gene and specific changes in the synaptotagmin 6(SYT6)gene,which may be responsible for the reduced fertility of the giant panda.Positive selection analysis between the two subspecies indicated that the reproduction-associated IQ motif containing D(IQCD)gene may at least partly explain the different reproduction rates of the two subspecies.Furthermore,several genes in the Hippo pathway exhibited signs of rapid evolution with giant panda-specific variants and divergent regulatory elements,which may contribute to the reduced inner organ sizes of the giant panda. 展开更多
关键词 Giant panda Chromosome-level genome Divergence time Reduced fertility Inner organ size
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Simulation-oriented model reuse in cyber-physical systems: A method based on constrained directed graph
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作者 Wenzheng Liu heming zhang +2 位作者 Chao Tang Shuangfei Wu Hongguang Zhu 《International Journal of Modeling, Simulation, and Scientific Computing》 EI 2022年第2期91-110,共20页
Modeling and Simulation of Cyber-Physical Systems(MSCPS)is demanding in terms of immediate response to dynamic and complex changes of CPS.Simulation-oriented model reuse can be used to build a whole CPS model by reusi... Modeling and Simulation of Cyber-Physical Systems(MSCPS)is demanding in terms of immediate response to dynamic and complex changes of CPS.Simulation-oriented model reuse can be used to build a whole CPS model by reusing developed models in a new sim-ulation application,which avoid repeated modeling and thus reduce the redevelopment of submodels.Model composition,one of the important methods,enables model reuse by selecting and adopting diversified integration solutions of simulation components to meet the requirements of simulation application systems.In this paper,a real-time model integration approach for global CPS modeling is proposed,which reuses devel-oped submodels by compositing submodel nodes.Specifically,a constrained directed graph of submodels for the whole system which can meet the simulation requirements is constructed by reverse matching.Submodel properties,including co-simulation distance between submodel nodes,reuse benefit and simulation performance of model nodes,are quantified.Based on the properties,the model-integrated solution for the whole CPS simulation is retrieved throughout the model constrained digraph by the Genetic Algo-rithm(GA).In the experiment,the proposed method is applied to a typical model integrated computing scenario containing multiple model-integration solutions,among which the Pareto optimal solutions are retrieved.Results show that the effectiveness of the model integration method proposed in this paper is verified. 展开更多
关键词 CPS model reuse model composition co-simulation distance multi-objective genetic algorithm
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Knowledge-driven material design platform based on the whole-process simulation and modeling
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作者 Gongzhuang Peng Tie Li +2 位作者 Xiang Zhai Wenzheng Liu heming zhang 《International Journal of Modeling, Simulation, and Scientific Computing》 EI 2022年第2期1-15,共15页
In order to realize the agility,collaboration and visualization of alloy material devel-opment process,a product development platform based on simulation and modeling technologies is established in this study.In this ... In order to realize the agility,collaboration and visualization of alloy material devel-opment process,a product development platform based on simulation and modeling technologies is established in this study.In this platform,the whole-process simulation module builds multi-level simulation models based on metallurgical mechanisms from the production line level,the thermo-mechanical coupling field level and the microstructure evolution level.The design knowledge management module represents the multi-source heterogeneous material design knowledge through ontology model,including customers’requirement knowledge,material component knowledge,process design knowledge and quality inspection knowledge,and utilizes the case-based reasoning approach to reuse the knowledge.The data-driven modeling module applies machine learning algorithms to mine the relationships between product mechanical properties,material components,and process parameters from historical samples,and utilizes multi-objective optimiza-tion algorithms to find the optimal combination of process parameters.Application of the developed platform in actual steel mills shows that the proposed method helps to improve the efficiency of product design process. 展开更多
关键词 Product development knowledge-based engineering multi-scale simulation performance prediction model
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A comprehensive survey on multimodal sentiment analysis:Techniques,models,and applications
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作者 heming zhang 《Advances in Engineering Innovation》 2024年第7期47-52,共6页
Multimodal sentiment analysis(MSA)is an evolving field that integrates information from multiple modalities such as text,audio,and visual data to analyze and interpret human emotions and sentiments.This review provide... Multimodal sentiment analysis(MSA)is an evolving field that integrates information from multiple modalities such as text,audio,and visual data to analyze and interpret human emotions and sentiments.This review provides an extensive survey of the current state of multimodal sentiment analysis,highlighting fundamental concepts,popular datasets,techniques,models,challenges,applications,and future trends.By examining existing research and methodologies,this paper aims to present a cohesive understanding of MSA,Multimodal sentiment analysis(MSA)integrates data from text,audio,and visual sources,each contributing unique insights that enhance the overall understanding of sentiment.Textual data provides explicit content and context,audio data captures the emotional tone through speech characteristics,and visual data offers cues from facial expressions and body language.Despite these strengths,MSA faces limitations such as data integration challenges,computational complexity,and the scarcity of annotated multimodal datasets.Future directions include the development of advanced fusion techniques,real-time processing capabilities,and explainable AI models.These advancements will enable more accurate and robust sentiment analysis,improve user experiences,and enhance applications in human-computer interaction,healthcare,and social media analysis.By addressing these challenges and leveraging diverse data sources,MSA has the potential to revolutionize sentiment analysis and drive positive outcomes across various domains. 展开更多
关键词 Multimodal Sentiment Analysis Natural Language Processing Emotion Recognition Data Fusion Techniques Deep Learning Models
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