检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

国地税合并与企业创新——抑制还是促进?

经济科学 2024年第3期 70-90页

作者：蔡伟贤周颖惠朱迪厦门大学经济学院

本文基于2013—2021年沪深A股上市公司数据,使用双重差分模型评估了国地税合并对企业创新的影响。研究发现:国地税合并总体上显著促进了企业创新,这一结论在进行一系列稳健性检验后依旧成立。机制和异质性分析表明,国地税合并通过征税... 详细信息

本文基于2013—2021年沪深A股上市公司数据,使用双重差分模型评估了国地税合并对企业创新的影响。研究发现:国地税合并总体上显著促进了企业创新,这一结论在进行一系列稳健性检验后依旧成立。机制和异质性分析表明,国地税合并通过征税渠道抑制了企业创新,但通过治理渠道和税收营商环境渠道促进了企业创新,且促进作用在信息透明度较低、公司治理水平较低、地区营商环境较差的企业中更为显著。进一步分析发现,国地税合并提高了企业创新质量和创新效率,兼具“提质”和“增效”双重效应。本文结论表明,统一、规范的税收征管有助于激发企业创新活力,为深化税收征管改革、建设现代化财税体系提供了经验支持。

关键词：国地税合并企业创新税收征管公司治理税收营商环境

Influence of travel speed on microstructure and mechanical properties of wire + arc additively manufactured 2219 aluminum alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2020年第2期37卷 143-153页

作者： yinghui zhou Xin Lin Nan Kang Weidong Huang Jiang Wang Zhennan Wang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design MIIT ChinaNorthwestern Polytechnical UniversityXi’an 710072China

Wire+arc additive manufacturing(WAAM)was preliminarily employed to fabricate the 2219 aluminum *** influence of the electric arc travel speed(TS)on the macro-morphology,microstructure,and mechanical properties were *** results indicated that as the electric arc TS increased,the size and the volume fraction of equiaxed grain *** high arc TS during WAAM also promoted the precipitation of theθ(Al2Cu)*** volume fractions ofθ’’andθ’phases reached maximum values when TS is 350 and 250 mm/min,*** thermal cycle facilitated the precipitation of theθ’*** addition,the micro-hardness and tensile strength of the alloy were analyzed,and the results indicated that samples fabricated at TS of 350 mm/min possessed finer equiaxed grain and exhibited higher ultimate tensile strength(273.5 MPa)and yield strength(182.9 MPa)compared to those fabricated at 250 mm/min.

关键词： Wire+arc additive manufacturing 2219 aluminum alloy Microstructure Mechanical properties

Precipitation and hot deformation behavior of austenitic heat-resistant steels: A review

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2017年第12期33卷 1448-1456页

作者： yinghui zhou Yongchang Liu Xiaosheng zhou Chenxi Liu Jianxin Yu Yuan Huang Huijun Li Wenya Li State Key Lab of Hydraulic Engineering Simulation and Safety School of Materials Science & Engineering Tianjin University School of Materials Science & Engineering Northwestern Polytechnical University Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration Shanghai Jiao Tong University

The austenitic heat resistant-steels have been considered as important candidate materials for advanced supercritical boilers, nuclear reactors, super heaters and chemical reactors, due to their favorable combination of high strength, corrosion resistance, perfect mechanical properties, workability and low *** the precipitation behavior of the steels during long-term service at elevated temperature would lead to the deterioration of mechanical properties, it is essential to clarify the evolution of secondary phases in the microstructure of the steels. Here, a summary of recent progress in the precipitation behavior and the coarsening mechanism of various precipitates during aging in austenitic steels is made. Various secondary phases are formed under service conditions, like MX carbonitrides, M_（23）C_6 carbides, Z phase, sigma phase and Laves phase. It is found that the coarsening rate of M_（23）C_6 carbides is much higher than that of MX carbonitrides. In order to understand the thermal deformation mechanism, a constitutive equation can be established, and thus obtained processing maps are beneficial to optimizing thermal processing parameters, leading to improved thermal processing properties of steels.

关键词： Austenitic steels Coarsening behavior Hot deformation Microstructure

在线全文

学校读者我要写书评

暂无评论

“学为主体”在微课教学中的体现

电气电子教学学报 2024年第1期46卷 184-186页

作者：苏丽媛周颖慧郭飞易韵陆军工程大学南京210071

“学为主体,教为主导”的教学理念已经在现代教学中得到广泛推广,但是对于以短视频为主要呈现形式的微课,由于其教学方式与传统教学有很大不同,具有不直接与学员交流的特点,教师在教学设计的全过程中往往会忽视“学为主体”的体现。因... 详细信息

“学为主体,教为主导”的教学理念已经在现代教学中得到广泛推广,但是对于以短视频为主要呈现形式的微课,由于其教学方式与传统教学有很大不同,具有不直接与学员交流的特点,教师在教学设计的全过程中往往会忽视“学为主体”的体现。因此结合现代微课的特征和教学过程,分析微课教学“学为主体”理念的必要性和体现方式,对“学为主体”教学理念在微课教学中的实践进行探索。

关键词：微课学为主体互动

CVD synthesis of nitrogen-doped graphene using urea

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2015年第10期58卷 94-99页

作者： ZHANG CanKun LIN WeiYi ZHAO ZhiJuan ZHUANG PingPing ZHAN LinJie zhou yinghui CAI WeiWei Department of Physics Laboratory of Nanoscale Condense Matter Physics and State Key Laboratory of Physical Chemistry of Solid SurfacesXiamen University

This work provides an effective low-cost synthesis and in-depth mechanistic study of high quality large-area nitrogen-doped graphene(NG) films. These films were synthesized using urea as nitrogen source and methane as carbon source, and were characterized by scanning electron microscopy(SEM), Raman spectroscopy and X-ray photoelectron spectroscopy(XPS). The N doping level was determined to be 3.72 at.%, and N atoms were suggested to mainly incorporated in a pyrrolic N configuration. All distinct Raman peaks display a shift due to the nitrogen-doping and compressive strain. The increase in urea concentration broadens the D and 2D peak's Full Width at Half Maximum(FWHM), due to the decrease of mean free path of phonons. The N-doped graphene exhibited an n-type doping behavior with a considerably high carrier mobility of about 74.1 cm2/(V s), confirmed by electrical transport measurements.

关键词： nitrogen-doped graphene chemical vapor deposition Raman spectroscopy X-ray photoemission spectroscopy

A Method of Multimodal Emotion Recognition in Video Learning Based on Knowledge Enhancement

在线全文

学校读者我要写书评

暂无评论

Computer Systems Science & Engineering 2023年第11期47卷 1709-1732页

作者： Hanmin Ye yinghui zhou Xiaomei Tao School of Information Science and Engineering Guilin University of TechnologyGuilin541004China Guangxi Key Laboratory of Embedded Technology and Intelligent System Guilin University of TechnologyGuilin541004China Guangxi Key Lab of Multi-Source Information Mining and Security Guangxi Normal UniversityGuilin541004China

With the popularity of online learning and due to the significant influence of emotion on the learning effect,more and more researches focus on emotion recognition in online *** of the current research uses the comments of the learning platform or the learner’s expression for emotion *** research data on other modalities are *** of the studies also ignore the impact of instructional videos on learners and the guidance of knowledge on *** of the need for other modal research data,we construct a synchronous multimodal data set for analyzing learners’emotional states in online learning *** data set recorded the eye movement data and photoplethysmography(PPG)signals of 68 subjects and the instructional video they *** the problem of ignoring the instructional videos on learners and ignoring the knowledge,a multimodal emotion recognition method in video learning based on knowledge enhancement is *** method uses the knowledge-based features extracted from instructional videos,such as brightness,hue,saturation,the videos’clickthrough rate,and emotion generation time,to guide the emotion recognition process of physiological *** method uses Convolutional Neural Networks(CNN)and Long Short-Term Memory(LSTM)networks to extract deeper emotional representation and spatiotemporal information from shallow *** model uses multi-head attention(MHA)mechanism to obtain critical information in the extracted deep ***,Temporal Convolutional Network(TCN)is used to learn the information in the deep features and knowledge-based ***-based features are used to supplement and enhance the deep features of physiological ***,the fully connected layer is used for emotion recognition,and the recognition accuracy reaches 97.51%.Compared with two recent researches,the accuracy improved by 8.57%and 2.11%,*** the four public data sets,our proposed method also achieves bett

关键词： Emotion recognition video learning physiological signal knowledge enhancement deep learning CNN LSTM TCN

Enhanced Raman scattering of graphene on Ag nanoislands

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2014年第11期57卷 2021-2023页

作者： HU Wei HUANG ZhiYi zhou yinghui CAI WeiWei KANG JunYong Department of Physics Xiamen University

The effect of Ag nanoislands on the Raman of graphene was investigated in this *** with that on the bare silicon wafer,Raman enhancement was observed in the graphene film that covered on Ag/Si surface with nanoscale Ag islands,which would be induced by the localized plasmon resonance in Ag *** interaction between the graphene sheet and Ag/Si substrate was further *** peak shift and line shape of Raman spectroscopy indicated a nonuniform strain distribution in the Ag/Si supported graphene film.

关键词： graphene nanostructure Raman

不同采烤方式上部烟叶外观质量及抗氧化特性分析

在线全文

学校读者我要写书评

暂无评论

烟草科技 2024年第2期57卷 37-44页

作者：刘峰峰孟霖何结望周迎辉石刚彭五星乾艳杨秀军孙福山湖北中烟工业有限责任公司武汉市430062 中国农业科学院烟草研究所山东省青岛市266000 湖北省烟草公司恩施州公司湖北省恩施州445500

为明确带茎采烤上部烟叶的品质特点及其形成机理,以云烟87为试材分析了上部烟叶带茎采烤和逐叶采烤烟叶外观质量特点、烘烤阶段干球温度关键稳温点的烟叶显微结构和抗氧化能力的差异。结果表明:(1)带茎采烤上部烟叶外观质量显著好于逐... 详细信息

为明确带茎采烤上部烟叶的品质特点及其形成机理,以云烟87为试材分析了上部烟叶带茎采烤和逐叶采烤烟叶外观质量特点、烘烤阶段干球温度关键稳温点的烟叶显微结构和抗氧化能力的差异。结果表明:(1)带茎采烤上部烟叶外观质量显著好于逐叶采烤,其颜色特征黄色面积、L^(*)值、b^(*)值较高而a^(*)值较低。(2)随着烘烤阶段的推进,在关键稳温点,带茎采烤上部烟叶组织细胞消融皱缩破坏程度滞后于逐叶采烤。(3)随着烘烤阶段的推进,烟叶细胞膜脂质过氧化物(LPO)、丙二醛(MDA)含量(质量分数)总体均呈现升高趋势,均在定色阶段46℃末达到最高,且带茎采烤上部烟叶比逐叶采烤分别降低21.02%和32.01%;烟叶过氧化氢(H_(2)O_(2))含量和超氧阴离子(O_(2)^(-)·)产生速率总体均呈现逐渐升高的趋势,且带茎采烤上部烟叶在变黄阶段均低于逐叶采烤,在定色阶段46℃末则显著提高。(4)随着烘烤阶段的推进,带茎采烤上部烟叶超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性总体高于逐叶采烤烟叶;带茎采烤上部烟叶谷胱甘肽还原酶(GR)活性呈逐步升高又降低的趋势,在变黄阶段42℃末达到最高,而逐叶采烤的烟叶GR活性呈慢-快-慢升高的趋势,在定色阶段46℃末达到最高,且变黄阶段带茎采烤上部烟叶GR活性高于逐叶采烤烟叶;带茎采烤上部烟叶总抗氧化能力(T-AOC)总体呈逐步升高的趋势,且高于逐叶采烤烟叶,在变黄阶段40℃末、定色阶段46℃末,带茎采烤与逐叶采烤上部烟叶T-AOC的差异达到显著水平。总之,带茎采烤上部烟叶的外观质量较好,这与烘烤过程中烟叶组织细胞消融破坏程度滞后和抗氧化能力较强密切相关。

关键词：烤烟上部烟叶带茎采烤外观质量显微结构抗氧化特性

Effect of Cu content on microstructure and mechanical properties of in-situ β phases reinforced Ti/Zr-based bulk metallic glass matrix composite by selective laser melting(SLM)

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第8期67卷 174-185页

作者： Xuehao Gao Xin Lin Qiaodan Yan Zihong Wang Xiaobin Yu yinghui zhou Yunlong Hu Weidong Huang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an710072China Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design MUT ChinaNorthwestern Polytechnical UniversityXi'an710072China

In this study,non-toxic in-situβphases of reinforced Ti/Zr-based bulk metallic glass matrix composites(BMGCs)of(Ti_(0.65)Zr_(0.35))100-xCux(x=5,10,15 at.%)are fabricated via selective laser *** effect of Cu content on phase formation,microstructure,and mechanical properties is *** average volume fraction and width of theβphase decreases with increasing Cu content,while a more amorphous phase and the(Ti,Zr)_(2)Cu phase *** the center zone of the molten pool,theβphase grows in the direction of the temperature gradient,and the amorphous phase distributes among theβ*** occurs using:sphere morphology(for x=5),a more continuous elongated sphere and network morphology(for x=10),and network morphology(for x=15),*** the edge zone of the molten pool,due to the smaller cooling rate and the existence of a partially molten zone,theβphase becomes coarser,and an amorphous phase forms for more continuous ***,the hardness improves significantly with increasing Cu *** crack is found for x=*** the average volume fraction of theβphase for x=5 is about 90%,the compression yield strength is 1386±64 MPa,reaching to an average level of conventionally fabricated counterparts,due to finer microstructure,and twinning and martensitic transformation of theβphase.

关键词： Metallic glass Amorphous phase βPhase Bulk metallic glass matrix composites(BMGCs) Additive manufacturing(AM) Selective laser melting(SLM)