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Covalent Organic Frameworks with trans-Dimensionally Vinylene-linked π-Conjugated Motifs

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Chemical Research in Chinese Universities 2022年第2期38卷 382-395页

作者： BI Shuai MENG Fancheng zhang zixing WU Dongqing zhang Fan School of Chemistry and Chemical Engineering Shanghai Jiao Tong UniversityShanghai 200240P.R.China

Vinylene-linked covalent organic frameworks(COFs) are a class of promising porous organic materials that feature fully π-conjugated structures, high crystallinity, permanent porosity, ultrahigh chemical stability, and extraordinary optoelectronic properties. Over the past 5 years, this kind of material has been witnessed rapid development either in chemical synthesis or in potential applications. In this review, we summarize the chemistry to synthesize vinylene-linked COFs, especially the synthetic strategies involving activation of aryl methyl groups for condensation reaction. We then scrutinize the state-of-the-art development in properties and functions of this kind of COFs. Our own opinions on the further development of the vinylene-linked COFs are also presented for discussion.

关键词： Covalent organic framework(COF) Vinylene linkage Stability π-Conjugated structure Semiconducting property

Age-hardening characteristic of an Al-Zn-Mg-Cu alloy produced by spray deposition

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Rare Metals 2007年第2期26卷 163-168页

作者： WANG Feng XIONG Baiqing zhang Yongan ZHU Baohong LIU Hongwei zhang Zhihui WANG zixing State Key Laboratory for Fabrication and Processing of Nonferrous Metals Beijing General Research Institute for Nonferrous Metals Beijing 100088 China

Al-10.8Zn-2.8Mg-1.9Cu alloy was synthesized by spray atomization and deposition technique. GP zones and age-hardening process in the alloy were investigated using high-resolution electron microscopy （HREM）, selected area diffraction （SAD）, and differential scanning calorimetry （DSC） analysis. The results indicated that spray deposition process accelerated the aging kinetics of the alloy at an aging temperature of 120℃, thereby reducing the peak aging time to 16 h. GPⅠ and GPⅡ are the two types of zones that are major precipitates for the alloy under peak-aged condition. The precipitation sequence for the alloy is also discussed.

关键词： aluminium alloy precipitation GP zone spray deposition

Deep Scalogram Representations for Acoustic Scene Classification

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IEEE/CAA Journal of Automatica Sinica 2018年第3期5卷 662-669页

作者： Zhao Ren Kun Qian zixing zhang Vedhas Pandit Alice Baird Bjorn Schuller ZD.B Chair of Embedded Intelligence for Health Care and Wellbeing University of Augsburg Germany Machine Intelligence and Signal Processing Group Technische Universitat Munchen Group on Language Audio and Music (GLAM) Imperial College London UK IEEE

Spectrogram representations of acoustic scenes have achieved competitive performance for acoustic scene classification. Yet, the spectrogram alone does not take into account a substantial amount of time-frequency information. In this study, we present an approach for exploring the benefits of deep scalogram representations, extracted in segments from an audio stream. The approach presented firstly transforms the segmented acoustic scenes into bump and morse scalograms, as well as spectrograms; secondly, the spectrograms or scalograms are sent into pre-trained convolutional neural networks; thirdly,the features extracted from a subsequent fully connected layer are fed into(bidirectional) gated recurrent neural networks, which are followed by a single highway layer and a softmax layer;finally, predictions from these three systems are fused by a margin sampling value strategy. We then evaluate the proposed approach using the acoustic scene classification data set of 2017 IEEE AASP Challenge on Detection and Classification of Acoustic Scenes and Events(DCASE). On the evaluation set, an accuracy of 64.0 % from bidirectional gated recurrent neural networks is obtained when fusing the spectrogram and the bump scalogram, which is an improvement on the 61.0 % baseline result provided by the DCASE 2017 organisers. This result shows that extracted bump scalograms are capable of improving the classification accuracy,when fusing with a spectrogram-based system.

关键词： Acoustic scene classification(ASC) (bidirectional) gated recurrent neural networks((B) GRNNs) convolutional neural networks(CNNs) deep scalogram representation spectrogram representation

Improvement of Stress-rupture Life for Modified-HR6W Austenitic Stainless Steel

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Journal of Materials Science & Technology 2011年第11期27卷 1059-1064页

作者： Shiyun Cui zixing zhang Yulai Xu Jun Li Xueshan Xiao Changchun Zhu Institute of Materials Shanghai University Shanghai 200072 China Baoshan Iron ＆ Steel Co. Ltd. Shanghai 200940 China

Stress-rupture life of HR6W austenitic stainless steel modified with B and Mg additions was measured, and the microstructures were analyzed by optical microscopy, X-ray diffraction, scanning electron microscopy and transmission electron microscopy equipped with energy dispersive spectroscopy. The results indicated that the enhancement of the stress-rupture life was mainly due to the precipitation with B in the elemental form at the grain boundaries, and the improvement of the form of carbides at grain boundaries and the removal of O and S elements by addition of Mg. The micro-alloying elements have a beneficial effect on stress-rupture life of the modified-HR6W austenitic stainless steel at high temperature.

关键词： HR6W Micro-alloying Stress-rupture life Microstructure

The role of watermelon caffeic acid O-methyltransferase (ClCOMT1) in melatonin biosynthesis and abiotic stress tolerance

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Horticulture Research 2021年第1期8卷 2937-2948页

作者： Jingjing Chang Yanliang Guo Jingyi Yan zixing zhang Li Yuan Chunhua Wei Yong zhang Jianxiang Ma Jianqiang Yang Xian zhang Hao Li State Key Laboratory of Crop Stress Biology for Arid Areas College of HorticultureNorthwest A&F UniversityYanglingShaanxiChina State Key Laboratory of Vegetable Germplasm Innovation TianjinChina

Melatonin is a pleiotropic signaling molecule that regulates plant growth and responses to various abiotic *** last step of melatonin synthesis in plants can be catalyzed by caffeic acid O-methyltransferase(COMT),a multifunctional enzyme reported to have N-acetylserotonin O-methyltransferase(ASMT)activity;however,the ASMT activity of COMT has not yet been characterized in nonmodel plants such as watermelon(Citrullus lanatus).Here,a total of 16 putative O-methyltransferase(ClOMT)genes were identified in *** them,ClOMT03(Cla97C07G144540)was considered a potential COMT gene(renamed ClCOMT1)based on its high identities(60.00–74.93%)to known COMT genes involved in melatonin biosynthesis,expression in almost all tissues,and upregulation under abiotic *** ClCOMT1 protein was localized in the *** of ClCOMT1 significantly increased melatonin contents,while ClCOMT1 knockout using the CRISPR/Cas-9 system decreased melatonin contents in watermelon *** results suggest that ClCOMT1 plays an essential role in melatonin biosynthesis in *** addition,ClCOMT1 expression in watermelon was upregulated by cold,drought,and salt stress,accompanied by increases in melatonin *** of ClCOMT1 enhanced transgenic Arabidopsis tolerance against such abiotic stresses,indicating that ClCOMT1 is a positive regulator of plant tolerance to abiotic stresses.

关键词： methyltransferase COMT stress

Self-attention transfer networks for speech emotion recognition

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Virtual Reality & Intelligent Hardware 2021年第1期3卷 43-54页

作者： Ziping ZHAO Keru Wang Zhongtian BAO zixing zhang Nicholas CUMMINS Shihuang SUN Haishuai WANG Jianhua TAO Björn WSCHULLER College of Computer and Information Engineering Tianjin Normal UniversityTianjin 300387China GLAM-Group on Language Audio&MusicImperial College LondonSW72AZUK Chair of Embedded Intelligence for Health Care and Wellbeing University of Augsburg86159Germany Department of Biostatistics and Health Informatics IoPPNKing's College LondonLondonSE58AFUK Department of Computer Science and Engineering Fairfield University 06824USA National Laboratory of Pattern Recognition CASIABeijing 100190China

Background A crucial element of human-machine interaction,the automatic detection of emotional states from human speech has long been regarded as a challenging task for machine learning *** vital challenge in speech emotion recognition(SER)is learning robust and discriminative representations from *** machine learning methods have been widely applied in SER research,the inadequate amount of available annotated data has become a bottleneck impeding the extended application of such techniques(e.g.,deep neural networks).To address this issue,we present a deep learning method that combines knowledge transfer and self-attention for SER ***,we apply the log-Mel spectrogram with deltas and delta-deltas as ***,given that emotions are time dependent,we apply temporal convolutional neural networks to model the variations in *** further introduce an attention transfer mechanism,which is based on a self-attention algorithm to learn long-term *** self-attention transfer network(SATN)in our proposed approach takes advantage of attention transfer to learn attention from speech recognition,followed by transferring this knowledge into *** evaluation built on Interactive Emotional Dyadic Motion Capture(IEMOCAP)dataset demonstrates the effectiveness of the proposed model.

关键词： Speech emotion recognition Attention transfer Self-attention Temporal convolutional neural networks(TCNs)

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变比为2的升压型开关电容变换器研究

中国电机工程学报 2017年第10期37卷 2963-2970页

作者：蔡慧包莅庭张子省由甲川中国计量大学机电工程学院浙江省杭州市310018

研究一种变比为2的升压型开关电容变换器。该变换器基于开关电容原理,不含磁性元件,具有体积小、重量轻和功率密度高的特点。开关元件的脉宽调制控制驱动方式和电路拓扑简单。给出了升压型变换器的工作过程和控制驱动方式,在考虑寄生参... 详细信息

研究一种变比为2的升压型开关电容变换器。该变换器基于开关电容原理,不含磁性元件,具有体积小、重量轻和功率密度高的特点。开关元件的脉宽调制控制驱动方式和电路拓扑简单。给出了升压型变换器的工作过程和控制驱动方式,在考虑寄生参数的情况下,针对开关电容变换器提出一种新的分析方法,通过暂态建模,得到变换器等效内阻的数学模型和稳态变比的解析分析;给出变换器性能与电路参数之间的函数关系和变换器设计原则;根据得到的设计原则进行了变换器参数设计。相关的实验结果表明了理论分析的正确性。

关键词：开关电容变换器升压变换器交-交变换暂态分析

大气颗粒物滤膜中极性有机物在线衍生装置的设计与应用

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色谱 2022年第1期40卷 100-106页

作者：张晗廖旭魏来张子兴任红云张娴中国科学院城市环境研究所环境与健康重点实验室福建厦门361021

设计制作了一套用于气相色谱-质谱(GC-MS)分析极性有机物的在线衍生装置,并将其应用于大气颗粒物样品中极性有机物的检测。将大气颗粒物滤膜样品置于GC-MS进样口,通过使用套针组件,匀速引入气态衍生试剂N-甲基-N-(三甲基硅烷)三氟乙酰胺... 详细信息

设计制作了一套用于气相色谱-质谱(GC-MS)分析极性有机物的在线衍生装置,并将其应用于大气颗粒物样品中极性有机物的检测。将大气颗粒物滤膜样品置于GC-MS进样口,通过使用套针组件,匀速引入气态衍生试剂N-甲基-N-(三甲基硅烷)三氟乙酰胺(MSTFA),使其在衬管内于310℃下与待测物接触,10 min即可完成硅烷化在线反应。反应过程中,色谱柱箱保持低温,衍生产物得以在柱头保留,反应完成后色谱柱箱程序升温,使衍生产物直接进行后续分离检测。应用在线衍生装置建立有机酸分析方法,获得了一元酸、二元酸、芳香酸、醇等极性有机物的检测信息,涵盖了大气化学分析常见的大部分目标化合物。该方法检出限为0.02~0.53 mg/L,线性相关系数为0.976~0.996,日内、日间RSD为0.27%~7.28%,适用于批量大气环境样品检测。与传统离线衍生技术相比,本装置使衍生反应处于高温惰性气体氛围,排除空气中水分对衍生试剂的损耗和衍生产物降解风险,反应稳定、效率高;固体滤膜上有机物进行热解吸的同时完成在线衍生,样品需求量小,操作简单,零有机试剂污染,并有望应用于醇类、酚类等多种极性有机化合物的分析。此外,该装置搭建简单,可模块化设计,适用于不同品牌气相色谱仪,具有商业化推广前景。

关键词：气相色谱质谱硅烷化反应在线衍生极性有机物大气颗粒物装置

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阻尼填充墙钢框架抗震性能试验研究

建筑结构学报 2018年第S1期39卷 71-78页

作者：邹祖银李少强朱占元张自兴常淑珍四川农业大学土木工程学院四川都江堰611830 四川农业大学村镇建设防灾减灾四川省高等学校工程研究中心四川都江堰611830 国网四川省电力公司绵阳供电公司四川绵阳621000

为研究带阻尼填充墙钢框架的抗震性能,设计了足尺的阻尼填充墙钢框架、普通填充墙钢框架试件和空钢框架试件各1榀,对试件进行了低周反复荷载试验。对比分析了不同试件在低周反复荷载作用下的破坏现象、滞回性能、骨架曲线、刚度退化和... 详细信息

为研究带阻尼填充墙钢框架的抗震性能,设计了足尺的阻尼填充墙钢框架、普通填充墙钢框架试件和空钢框架试件各1榀,对试件进行了低周反复荷载试验。对比分析了不同试件在低周反复荷载作用下的破坏现象、滞回性能、骨架曲线、刚度退化和耗能能力等。试验结果表明:阻尼填充墙钢框架在相同的荷载作用下墙体的开裂程度比普通填充墙的轻,墙体开裂荷载有一定提高;耗能砂浆和阻尼层起到耗散地震能量的作用,阻尼填充墙钢框架具有良好的位移延性;相对于普通填充墙钢框架墙体形成的“X”剪切裂缝,阻尼填充墙钢框架的墙体裂缝被阻尼层隔断,改变了填充墙的破坏模式;耗能砂浆和阻尼层改变了填充墙的内力分布和裂缝开展方式,提高了阻尼填充墙钢框架的抗震性能。因此,耗能砂浆和阻尼层对填充墙钢框架的受力模式、滞回性能、延性等抗震性能有利,可作为结构设计时参考应用。

关键词：钢框架砌体填充墙耗能砂浆阻尼层拟静力试验抗震性能