检索结果-南通市图书馆

Finite Element Simulation of Flexible Roll Forming with Supplemented Material Data and the Experimental Verification

引用

Chinese Journal of Mechanical Engineering 2016年第2期29卷 342-350页

作者： yan Yu WANG Haibo LI qiang GUAN yanzhi School of Mechanical and Material Engineerin North China University of Technology

Flexible roll forming is a promising manufacturing method for the production of variable cross section products. Considering the large plastic strain in this forming process which is much larger than that of uniform deformation phase of uniaxial tensile test, the widely adopted method of simulating the forming processes with non-supplemented material data from uniaxial tensile test will certainly lead to large error. To reduce this error, the material data is supplemented based on three constitutive models. Then a finite element model of a six passes flexible roll forming process is established based on the supplemented material data and the original material data from the uniaxial tensile test. The flexible roll forming experiment of a B pillar reinforcing plate is carried out to verify the proposed method. Final cross section shapes of the experimental and the simulated results are compared. It is shown that the simulation calculated with supplemented material data based on Swift model agrees well with the experimental results, while the simulation based on original material data could not predict the actual deformation accurately. The results indicate that this material supplement method is reliable and indispensible, and the simulation model can well reflect the real metal forming process. Detailed analysis of the distribution and history of plastic strain at different positions are performed. A new material data supplement method is proposed to tackle the problem which is ignored in other roll forming simulations, and thus the forming process simulation accuracy can be greatly improved.

关键词： 3D Flexible roll forming constitutive model material data supplementation finite element method experiment verification

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Speech Enhancement Using Multi-channel Post-Filtering with Modified Signal Presence Probability in Reverberant Environment

引用

Chinese Journal of Electronics 2016年第3期25卷 512-519页

作者： WANG Xiaofei GUO yanmeng FU qiang yan Yonghong Key Laboratory of Speech Acoustics and Content Understanding Institute of AcousticsChinese Academy of Sciences

In this paper, a multi-channel post-filtering approach in reverberant environment based on detection and estimation scheme is presented. A modified Signal presence probability(SPP), which is in consideration of reverberation, is proposed with a novel estimator Direct-toreverberate ratio(DRR) to adapt to distant-talking *** is known a key estimator to instruct the updating of transient noise or residual directional interference and form gain function in the time-frequency domain, consequently a new desired signal detection scheme is proposed to improve its accuracy. Appropriate spectral enhancement technique is applied to the noisy speech signal taking advantage of the modified SPP estimator. The proposed multi-channel post-filtering is tested in different nonstationary noisy and reverberant environments. Experimental results show that it achieves considerable improvement on signal preservation of the desired speech with more noise reduction over the comparative algorithms.

关键词： Speech enhancement Multi-channel post-filtering Reverberation robust Signal detection

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

A novel molecular mechanism for nitrated α-synuclein-induced cell death

引用

Journal of Molecular Cell Biology 2011年第4期3卷 239-249页

作者： yanying Liu Min qiang yan Wei Rongqiao He State Key Laboratory of Brain and Cognitive Sciences Institute of BiophysicsChinese Academy of Sciences15 Datun RoadChaoyang DistrictBeijing 100101China Key Laboratory of Mental Health Institute of PsychologyChinese Academy of Sciences15 Datun RoadChaoyang DistrictBeijing 100101China

Although previous studies have demonstrated the involvement of nitrated a-synuclein in neurodegenerative disorders(synucleinopathies),the effects of nitrated α-synuclein and the molecular mechanisms underlying its toxicity are still *** the present study,nitrated α-synuclein with four 3-nitrotyrosines(Tyr^(39),Tyr^(125),Tyr^(133),and Tyr^(136))was obtained non-enzymatically by incubation with *** nitrated protein existed as a mixture of monomers,dimers,and polymers in *** nitrated a-synuclein could induce cell death in a time-and concentration-dependent manner when SH-SY5Y cells(a human neuroblastoma cell line)were incubated with the dimers and *** with anti-integrin α5β1 antibody partially rescued the SH-SY5Y cells from the cell *** blotting and immunoprecipitation revealed that the nitrated protein bound to integrin on the cell *** of nitric oxide(NO)and calcium-independent inducible NO synthase(iNOS)activity increased during the initial stages of the *** expression of phosphorylated focal adhesion kinase(FAK)decreased in the ***,an increase in caspase 3 activity was observed in SH-SY5Y *** results demonstrate that activation of iNOS and inhibition of FAK may both be responsible for the cell death induced by nitrated α-*** data suggest that the cytotoxicity of nitrated a-synuclein is mediated via an integrin-iNOS/-FAK signaling pathway,and that the nitration of α-synuclein plays a role in neuronal degeneration.

关键词： nitric oxide nitration neuronal death toxicity focal adhesion kinase calcium-independent inducible nitric oxide synthase

来源：

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

Dinosaur-associated Poaceae epidermis and phytoliths from the Early Cretaceous of China

引用

National Science Review 2018年第5期5卷 721-727页

作者： yan Wu Hai-Lu You Xiao-qiang Li Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences Institute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of Sciences CAS Center for Excellence in Life and Paleoenvironment College of Earth Sciences University of Chinese Academy of Sciences

Grasses(Poaceae) are human’s most important crop plants and among the most important extant clades of vascular plants. However, the origin and early evolution of grasses are controversial, with estimated ages from molecular dating ranging between 59 and 129 Ma(million years ago). Here we report the discovery of basalmost grasses from the late Early Cretaceous(Albian, 113-101 Ma) of China based on microfossils(silicified epidermal pieces and phytoliths) extracted from a special structure along the dentition of a basal hadrosauroid(duck-billed dinosaur). Thus, this discovery represents the earliest known grass fossils, and is congruent with previous estimations on grass origin and early evolution calibrated by oldest known fossil grasses, highlighting the role of fossils in molecular dating. This discovery also indicates deep-diverging grasses probably gained broad distribution across both Laurasian and Gondwanan continents during the Barremian(129-125 Ma).

关键词： Poaceae dinosaur phytolith epidermis Early Cretaceous

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

The Fulde-Ferrell-Larkin-Ovchinnikov states in s and d-wave superconductor with spin-dependent bandwidth imbalance on square lattice

引用

Science China(Physics,Mechanics & Astronomy) 2016年第1期59卷 92-97页

作者： Yong-Hui Wang Qing-qiang Meng yan Chen Department of Physics and State Key Laboratory of Surface Physics Fudan UniversityShanghai 200433China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093China

We study numerically the phase diagram for s and d-wave fermionic superftuidity/superconductivity with spin-dependent band- width imbalance on a two-dimensional square-lattice. We also investigate the spontaneous space symmetry breaking states at low temperatures by solving the Bogoliubov-de Gennes equations. It is found that, the spatial configuration of the order parameter, both the uni-directional Fulde-Ferrell-Larkin-Ovchinnikov （FFLO） states and the two-dimensional FFLO state may show up in the presence of finite spin-dependent bandwidth imbalance. Moreover, we calculate the spectra of local density of states, and the experimental proposals of observing such FFLO states are therefore suggested.

关键词： FFLO state superconductivity superfluidity

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Science and Technology Backyard: A novel approach to empower smallholder farmers for sustainable intensification of agriculture in China

引用

Journal of Integrative Agriculture 2019年第8期18卷 1657-1666页

作者： JIAO Xiao-qiang ZHANG hong-yan MA Wen-qi WANG Chong LI Xiao-lin ZHANG Fu-suo Center for Resources Environment and Food Security Department of Plant Nutrition/Key Laboratory of Plant-Soil InteractionsMinistry of Education China Agricultural University Beijing 100193 P.R.China College of Resources and Environment Science Hebei Agricultural University Baoding 071001 P.R.China

Sustainable feeding of the growing population in China without ecological destabilization is a grand challenge. In this populous country where agriculture is dominated by smallholder farming, developing innovative technology and translating scientific knowledge into action for smallholder farmers is a crucial step in addressing this challenge. Here, we present a novel approach for technology innovation and dissemination to achieve sustainable intensification in the fields of smallholder farmers. The Science and Technology Backyard(STB) is a hub in a rural area that links knowledge with practices to promote technology innovation and exchange. In this study, the framework and functions of STB are introduced, and the key implications for sustainable intensification across millions of smallholder farmers are explicitly stated:(i) develop innovative technology based on stated demands of farmers;(ii) disseminate technology by innovative social service models though combined top-down approaches with bottom-up measures to enable smallholders in rural areas. This paper provides a perspective on transformation of small-scale agriculture toward sustainable intensification in China and useful knowledge applicable to other developing countries.

关键词： smallholder farmers sustainable intensification technology innovation technology transfer Science and Technology Backyard

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A novel diffusion model considering curvature radius at the bonding interface in a titanium/steel explosive clad plate

引用

International Journal of Minerals,Metallurgy and Materials 2015年第9期22卷 956-965页

作者： Hai-tao Jiang qiang Kang Xiao-qian yan National Engineering Research Center for Advanced Rolling Technology University of Science and Technology Beijing China Railway Materials Technologies Company Limited

This article introduces an element diffusion behavior model for a titanium/steel explosive clad plate characterized by a typical curved interface during the heat-treatment process. A series of heat-treatment experiments were conducted in the temperature range from 750℃ to 950℃, and the effects of heat-treatment parameters on the microstructural evolution and diffusion behavior were investigated by optical microscopy, scanning electron microscopy, X-ray diffraction analysis, and electron-probe microanalysis. Carbon atoms within the steel matrix were observed to diffuse toward the titanium matrix and to aggregate at the bonding interface at 850℃ or lower; in contrast, when the temperature exceeded 850℃, the mutual diffusion of Ti and Fe occurred, along with the diffusion of C atoms, resulting in the for- marion of Ti-Fe intermetallics （Fe2Ti/FeTi）. The diffusion distances of C, Ti, and Fe atoms increased with increasing heating temperature and/or holding time. On the basis of this diffusion behavior, a novel diffusion model was proposed. This model considers the effects of various factors, including the curvature radius of the curved interface, the diffusion coefficient, the heating temperature, and the holding rime. The experimental results show good agreement with the calculated values. The proposed model could clearly provide a general prediction of the elements＇ diffusion at both straight and curved interfaces.

关键词： explosive bonding metal cladding diffusion models interfaces heat treatment

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Elucidation of the structure, antioxidant, and interfacial properties of flaxseed proteins tailored by microwave treatment

引用

Journal of Integrative Agriculture 2023年第5期22卷 1574-1589页

作者： YU Xiao DUAN Zi-qiang QIN Xiao-peng ZHU Ying-ying HUANG Feng-hong PENG Deng-feng BAI yan-hong DENG Qian-chun Oil Crops Research Institute Chinese Academy of Agricultural Sciences/Hubei Key Laboratory of Lipid Chemistry and Nutrition/Key Laboratory of Oilseeds ProcessingMinistry of Agriculture and Rural AffairsWuhan 430062P.R.China College of Food and Bioengineering Zhengzhou University of Light Industry/Henan Key Laboratory of Cold Chain Food Quality and Safety ControlZhengzhou 450002P.R.China

The microwave treatment is commonly applied to flaxseed to release nutrients, inactivate enzymes, remove cyanogens,and intensify flavors. The current study aimed to explore the influences of microwave exposure on the antioxidant and interfacial properties of flaxseed protein isolates(FPI), focusing on the altering composition and molecular *** results showed that after microwave exposure(700 W, 1–5 min), more compact assembly of storage proteins and subsequent permeation by membrane fragments of oil bodies occurred for cold-pressing flaxseed flours. Moreover, the particle sizes of FPI was progressively reduced with the decrement ranged from 37.84 to 60.66%(P<0.05), whereas the zeta potential values initially decreased and then substantially recovered during 1–5 min of microwave exposure. The conformation unfolding, chain cross-linking, and depolymerization were sequentially induced for FPI based on the analysis of fluorescence emission spectra, secondary structure, and protein subunit profiles, thereby affecting the dispersion or aggregation properties between albumin and globulin fractions in FPI. Microwave exposure retained specific phenolic acids and superior in vitro antioxidant activities of FPI. The inferior gas–water interface absorption and the loose/porous assembly structure were observed for the foams prepared by FPI, concurrent with obviously shrinking foaming properties upon microwave exposure. Improving oil–water interface activities of FPI produced the emulsion droplets with descending sizes and dense interface coating, which were then mildly destabilized due to the lipid leakage and weakened rheological behavior with microwave exposure extended to 5 min. Our findings elucidated that microwave treatment could tailor the application functionality of protein fractions in flaxseed based on their in situ structural remodeling.

关键词： microwave exposure flaxseed protein isolates antioxidant activities interfacial properties composition structure

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Median arcuate ligament syndrome complicated with gallbladder stones:A case report

引用

World Journal of Clinical Cases 2023年第32期11卷 7881-7887页

作者： Jun-qiang Dang Qing-qiang Wang yan-Ling yang Lin Shang Qi-Tian Bian hong-Jun Xiang Department of Hepatobiliary Surgery Xi’an Daxing HospitalXi’an 710016Shaanxi ProvinceChina Department of Hepatobiliary and Pancreatic Surgery Xijing HospitalAir Force Medical UniversityXi’an 710032Shaanxi ProvinceChina

BACKGROUND Median arcuate ligament syndrome(MALS)is a rare disease caused by compression of the celiac trunk artery by the median arcuate ligament(MAL).It can cause symptoms of postprandial abdominal pain,weight loss,and nausea and *** SUMMARY A 55-year-old woman was admitted due to abdominal pain,nausea and *** admission,the patient presented with epigastric pain that worsened after eating,without signs of peritoneal *** tomography angiography of the upper abdomen showed compression of the proximal segment of the abdominal trunk,local luminal stenosis with angular“fishhook”changes,which changed significantly during forceful inspiration and expiration;gallbladder stones;and multiple cysts in the *** duplex ultrasonography showed that peak systolic velocity was 352 cm/*** diagnosis of MALS was confirmed,an arch ligament release procedure was *** has no specific symptoms and can be misdiagnosed as other abdominal *** of MALS should be improved to avoid *** commonly used treatment option is MAL release and resection of the peripheral ganglion of the celiac trunk *** The diagnosis and treatment of MALS must be individualized,and MAL release is effective and provides immediate symptomatic relief.

关键词： Median arcuate ligament syndrome Celiac artery compression syndrome Operative decompression Case report

来源：

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

Automatic modulation recognition of radio fuzes using a DR2D-based adaptive denoising method and textural feature extraction

引用

Defence Technology（防务技术） 2024年第4期34卷 328-338页

作者： yangtian Liu Xiaopeng yan qiang Liu Tai An Jian Dai Science and Technology on Electromechanical Dynamic Control Laboratory School of Mechatronical EngineeringBeijing Institute of TechnologyBeijing 100081China China Research and Development Academy of Machinery Equipment Beijing 100089China

The identification of intercepted radio fuze modulation types is a prerequisite for decision-making in interference ***,the electromagnetic environment of modern battlefields is complex,and the signal-to-noise ratio(SNR)of such environments is usually low,which makes it difficult to implement accurate recognition of radio *** solve the above problem,a radio fuze automatic modulation recognition(AMR)method for low-SNR environments is ***,an adaptive denoising algorithm based on data rearrangement and the two-dimensional(2D)fast Fourier transform(FFT)(DR2D)is used to reduce the noise of the intercepted radio fuze intermediate frequency(IF)***,the textural features of the denoised IF signal rearranged data matrix are extracted from the statistical indicator vectors of gray-level cooccurrence matrices(GLCMs),and support vector machines(SVMs)are used for *** DR2D-based adaptive denoising algorithm achieves an average correlation coefficient of more than 0.76 for ten fuze types under SNRs of-10 d B and above,which is higher than that of other typical *** trained SVM classification model achieves an average recognition accuracy of more than 96%on seven modulation types and recognition accuracies of more than 94%on each modulation type under SNRs of-12 d B and above,which represents a good AMR performance of radio fuzes under low SNRs.

关键词： Automatic modulation recognition Adaptive denoising Data rearrangement and the 2D FFT(DR2D) Radio fuze

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：