检索结果-南通市图书馆

THEORY AND APPLICATION OF WAVELET ANALYSIS INSTRUMENT LIBRARY

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2006年第3期19卷 464-467页

作者： bo lin qin Shuren LIU Xiaofeng College of Mechanical Engineenng Chongqing University Chongqing 400044 China

Some new theory and algorithms on wavelet analysis are proposed, including continuous wavelet transform （CWT）, discrete wavelet transform （DWT）, wavelet package transform （WPT）, wavelet denosing and mother wavelet selection, etc. Using the component-based hierarchy mode, the platform for virtual instrument （VI） is constructed, and the functions such as data sampling, data analysis and data present, etc are provided. Subsequently, the wavelet analysis library is designed and developed. The library consists of expert system, experienced database, development platform and abundant wavelet analysis functional module, which together implement general and special wavelet analysis in the field of mechanical engineering, energy source, transportation and biomedicine, etc. Finally, the wavelet analysis virtual instrument library is applied to detect fault called engine knock. Experimental result indicates that the wavelet analysis virtual instrument library can efficiently solve the engineering problem such as detecting engine knock.

关键词： Wavelet analysis Virtual instrument library Engine knock

IMPROVED METHOD FOR HILBERT INSTANTANEOUS FREQUENCY ESTIMATION

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2007年第6期20卷 94-98页

作者： bo lin LIU Xiaofeng qin Shuren College of Mechanical Engineering Chongqing University Chongqing 400044 China

In the mechanical fault detection and diagnosis field, it is more and more important to analyze the instantaneous frequency （IF） character of complex vibration signal. The improved IF estimation method is put forward aiming at the shortage of traditional Hilbert transform. It is based on Hilbert transform in wavelet domain. With the help of relationship between the real part and the imaginary part obtained from the complex coefficient of continuous wavelet transform or the analyti- cal signal reconstructed in wavelet packet decomposition, the instantaneous phase function of the subcomponent is extracted. In order to improve the precise of IF estimated out, some means such as linear regression, adaptive filtering, resampling are applied into the instantaneous phase obtained, then, the central differencing operator is used to get desired IF. Simulation results with synthetic and gearbox fault signals are included to illustrate the proposed method.

关键词： Instantaneous frequency Hilbert transform Wavelet transform linear regression Adaptive filtering Resampling

Effect of trigger system on experimental dispersion characteristics of active surface wave testing

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2024年第2期23卷 311-318页

作者： lin Shibin Jeramy C.Ashlock Zhu Liming qin Zexiang Li bo Zhu Xingji Zhai Changhai State Key Laboratory of Precision Blasting Jianghan UniversityWuhan 430056China Hubei Key Laboratory of Blasting Engineering Jianghan UniversityWuhan 430056China Department of Civil Construction&Environmental EngineeringIowa State UniversityAmesIA 50010USA Wuhan Airport Road Development Co. Ltd.Wuhan 430065China School of Civil and Environmental Engineering Harbin Institute of TechnologyShenzhen 518055China Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of TechnologyHarbin 150090China Key Lab of Smart Prevention and Mitigation of Civil Engineering Disaster of the Ministry of Industry and Information Technology Harbin Institute of TechnologyHarbin 150090China

A trigger system is typically employed in active seismic testing to trigger and synchronize multichannel surface wave data *** effect of the trigger system on the dispersion image of surface waves is empirically known to be negligible,however,theoretical explanation regarding the effect of the trigger system is *** study systematically examines the theory for surface wave dispersion analysis and proves that the effect of the trigger system on a dispersion image is negligible via a solid theoretical ***,based on the new theoretical explanation,an alternative method that uses only the relative phase difference between sensors to extract dispersion characteristics with better conceptual clarity is *** active surface wave testing cases are considered to validate the theory and *** results indicate that(1)an accurate trigger system is not necessary for surface wave data acquisition,and(2)it is unnecessary to assume that the impact point is the generation point of the surface waves for the experimental dispersion analysis.

关键词： site investigation surface waves data acquisition dispersion

Text Difficulty Study:Do Machines Behave the Same as Humans Regarding Text Difficulty?

在线全文

学校读者我要写书评

暂无评论

Machine Intelligence Research 2024年第2期21卷 283-293页

作者： bowen Chen Xiao Ding Yi Zhao bo Fu Tingmao lin Bing qin Ting Liu Research Center for Social Computing and Information Retrieval Harbin Institute of TechnologyHarbin 150001China Fundamental Technology Center China Construction Bank Financial Technology Co.Ltd.Beijing 100033China

With the emergence of pre-trained models,current neural networks are able to give task performance that is comparable to ***,we know little about the fundamental working mechanism of pre-trained models in which we do not know how they approach such performance and how the task is solved by the *** example,given a task,human learns from easy to hard,whereas the model learns ***,difficulty-insensitive learning leads to great success in natural language processing(NLP),but little attention has been paid to the effect of text difficulty in *** propose a human learning matching index(HLM Index)to investigate the effect of text *** results show:1)LSTM gives more human-like learning behavior than ***,UID-Superlinear gives the best evaluation of text difficulty among four text difficulty *** nine tasks,some tasks’performance is related to text difficulty,whereas others are not.2)Model trained on easy data performs best in both easy and medium test data,whereas trained on hard data only performs well on hard test data.3)Train the model from easy to hard,leading to quicker convergence.

关键词： Cognition inspired natural language processing psycholinguistics explainability text difficulty curriculum learning

Effect of aflibercept combined with triamcinolone acetonide on aqueous humor growth factor and inflammatory mediators in diabetic macular edema

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2024年第2期17卷 297-303页

作者： De-Shuang Li Hong-Xia Liao Jing-lin Zhang bo qin Shenzhen Aier Eye Hospital Aier Eye HospitalJinan UniversityShenzhen 518031Guangdong ProvinceChina Guangzhou Aier Eye Hospital Jinan UniversityGuangzhou 510040Guangdong ProvinceChina

AIM:To investigate the efficacy of aflibercept combined with sub-tenon injection of triamcinolone acetonide(TA)in treating diabetic macular edema(DME)and to examine changes in growth factors and inflammatory mediator levels in aqueous humor after ***:Totally 67 DME patients(67 eyes)and 30 cataract patients(32 eyes)were enrolled as the DME group and the control group,*** DME group was divided into the aflibercept group(34 cases)and the aflibercept combined with TA group(combined group,33 cases).The aqueous humor of both groups was collected during the study *** aqueous levels of vascular endothelial growth factor(VEGF),monocyte chemoattractant protein-1(MCP-1),interleukin-6(IL-6),interleukin-8(IL-8),and interleukin-1β(IL-1β)were detected using a microsphere suspension array technology(Luminex 200TM).Aqueous cytokines,best-corrected visual acuity(BCVA),central macular thickness(CMT),and complications before and after treatment were compared between the aflibercept group and combined ***:The concentrations of VEGF,MCP-1,IL-6,and IL-8 in the aqueous humor were significantly higher in the DME group than those of the control group(all P0.05).CONCLUSION:The cytokines VEGF,MCP-1,IL-6,and IL-8 in the aqueous humor of DME patients are significantly *** and aflibercept combined with TA have good efficacy in DME patients,can effectively reduce CMT,improve the patient’s vision,and have high *** combined with TA can quickly downregulate the aqueous humor cytokines and help to relieve macular edema ***,the long-term eff

关键词： diabetic macular edema aqueous humor cytokines aflibercept triamcinolone acetonide

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

On Depolymerization

CCS Chemistry 2024年第2期6卷 297-312页

作者： bo qin Xi Zhang College of Chemistry and Chemical Engineering Hunan UniversityChangsha 410082 Department of Chemistry Tsinghua UniversityBeijing 100084

Polymers have become an essential part of modern life and the global economy on account of their costeffectiveness and versatile ***,most postconsumer polymer wastes are unrecycled,leading to environmental pollution and resource ***,as an efficient chemical recycling approach,holds great promise in establishing a circular polymer *** this review,we attempt to highlight recent and significant advancements in depolymerization *** key research topics are discussed:(1)depolymerization of commodity polymers to produce reusable monomers and high-value chemicals;(2)depolymerization of intrinsically depolymerizable *** is anticipated that this review will reflect the present status and future trends of this rapidly evolving realm of depolymerization.

关键词： depolymerization chemical recycling sustainable polymers circular polymer economy catalysis dynamic covalent chemistry

Transcriptomic analysis reveals the effects of maternal exposure to bisphenol AF on hypothalamic development in male neonatal mice

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第7期141卷 304-313页

作者： lin Lv Yuanyuan Li Xuanyue Chen Zhanfen qin State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China

Fragmented data suggest that bisphenol AF(BPAF),a chemical widely used in a variety of products,might have potential impacts on the ***,we employed male neonatal mice following maternal exposure to explore the effects of low-dose BPAF on hypothalamic development by *** found that maternal exposure to approximately 50μg/(kg·day)BPAF from postanal day(PND)0 to PND 15 altered the hypothalamic transcriptome,primarily involving the pathways and genes associated with extracellular matrix(ECM)and intercellular adhesion,neuroendocrine regulation,and neurological *** RNA analysis confirmed the changes in the expression levels of concerned ***,we further revealed that low-dose BPAF posed a stimulatory impact on pro-opiomelanocortin(POMC)neurons in the arcuate nucleus of the hypothalamus and induced the browning of inguinal white adipose *** findings indicate that developmental exposure to low-dose BPAF could interfere with hypothalamic development and thereby lead to alterations in the ***,5000μg/(kg·day)BPAF caused slighter,non-significant or even inverse alterations than the low dose of 50μg/(kg·day),displaying a dose-independent *** observations suggest that the the dose-independent effects of BPAF might be associated with oxidative stress and inflammatory responses caused by the high ***,our study highlights a risk of low-dose BPAF to human neuroendocrine regulation and metabolism.

关键词： Bisphenol AF Hypothalamus Transcriptomic alteration Pro-opiomelanocortin(POMC)neurons White adipose tissue browning

Mulberry leaf supplementation inhibits skatole deposition by regulating gut microbiota and upregulating liver cytochrome P4501A1 expression in finishing pigs

在线全文

学校读者我要写书评

暂无评论

Animal Nutrition 2024年第1期16卷 34-44页

作者： Yuqing Sun Xiaoming Men Tianbao lin bo Deng Shi Zhong Jinxi Huo Kaipeng qin Zhiqiang Lv Ziwei Xu Yougui Li Institute of Sericulture and Tea Zhejiang Academy of Agricultural Sciences298 Deshengzhong RoadShangchengHangzhou 310021China Institute of Animal Husbandry and Veterinary Science Zhejiang Academy of Agricultural Sciences298 Deshengzhong RoadShangchengHangzhou 310021China

Skatole,a strong fecal odor substance,is generated through microbial degradation of tryptophan in the animal *** easily accumulates in adipose tissue and affects meat *** this study,the effect of mulberry leaf supplementation on skatole in finishing pigs was *** a 35-day trial,20 finishing pigs(barrows and gilts)were fed with a basal diet or basal diet with 6%mulberry *** performance of the pigs(n=10)was automatically recorded by a performance-testing feeder system and 8 pigs in each treatment were slaughtered and sampled for the remaining *** and short-chain fatty acids were detected using HPLC and gas chromatography,*** microbiota were analyzed using 16S r RNA gene *** metabolomics analysis of feces and serum was performed with UHPLC-MS/*** major cytochrome P450(CYP)enzymes that catalyze skatole degradation in the liver were tested by using RT-PCR and Western *** of major bioactive compounds in mulberry leaves on the CYP genes were verified in the hepatic cell line Hep G2 in an in vitro test(n=3).In finishing pigs,mulberry leaf supplementation had no significant effect on the average daily gain,average daily feed intake,and feed conversion ratio(P>0.05),but reduced skatole levels in feces,serum,and backfat(P<0.05),and increased acetic acid levels in feces(P=0.027).Mulberry leaf supplementation decreased the relative abundance of the skatole-producing bacteria Megasphaera and Olsenella(P<0.05).Indole-3acetic acid,the intermediate that is essential for skatole production,was significantly reduced in feces by mulberry leaf supplementation(P<0.05)and was positively correlated with skatole content in feces(P=0.004).In pigs treated with mulberry leaves,liver CYP1A1 expression was increased(P<0.05)and was negatively correlated with skatole content in backfat(P=0.045).The in vitro test demonstrated that mulberry leaf polyphenols and polysaccharides could directly stimulate CYP1A1 expression in

关键词： Pig Skatole Mulberry leaf Microbiota Cytochrome P450

Enhanced Sensing Mechanism Based on Shifting an Exceptional Point

在线全文

学校读者我要写书评

暂无评论

Research 2024年第3期6卷 285-292页

作者： Xuan Mao Guo-qing qin Hao Zhang bo-Yang Wang Dan Long Gui-qin Li Gui-Lu Long Department of Physics State Key Laboratory of Low-Dimensional Quantum PhysicsTsinghua UniversityBeijing 100084China Beijing Institute of Radio Measurement The Second Academy of China Aerospace Science and Industry Corporation(CASIC)Beijing 100854China Purple Mountain Laboratories Nanjing 21111China Frontier Science Center for Quantum Information Beijing 100084China Beijing Academy of Quantum Information Sciences Beijing 100193China

Non-Hermitian systems associated with exceptional points (EPs) are expected to demonstrate a giant response enhancement for various sensors. The widely investigated enhancement mechanism based on diverging from an EP should destroy the EP and further limits its applications for multiple sensing scenarios in a time sequence. To break the above limit, here, we proposed a new enhanced sensing mechanism based on shifting an EP. Different from the mechanism of diverging from an EP, our scheme is an EP nondemolition and the giant enhancement of response is acquired by a slight shift of the EP along the parameter axis induced by perturbation. The new sensing mechanism can promise the most effective response enhancement for all sensors in the case of multiple sensing in a time sequence. To verify our sensing mechanism, we construct a mass sensor and a gyroscope with concrete physical implementations. Our work will deepen the understanding of EP-based sensing and inspire designing various high-sensitivity sensors in different physical systems.

关键词： mechanism shifting exceptional