期刊文献+
共找到158,794篇文章
< 1 2 250 >
每页显示 20 50 100
RepBoTNet-CESA:An Alzheimer’s Disease Computer Aided Diagnosis Method Using Structural Reparameterization BoTNet and Cubic Embedding Self Attention
1
作者 Xiabin Zhang Zhongyi Hu +1 位作者 Lei Xiao Hui Huang 《Computers, Materials & Continua》 SCIE EI 2024年第5期2879-2905,共27页
Various deep learning models have been proposed for the accurate assisted diagnosis of early-stage Alzheimer’s disease(AD).Most studies predominantly employ Convolutional Neural Networks(CNNs),which focus solely on l... Various deep learning models have been proposed for the accurate assisted diagnosis of early-stage Alzheimer’s disease(AD).Most studies predominantly employ Convolutional Neural Networks(CNNs),which focus solely on local features,thus encountering difficulties in handling global features.In contrast to natural images,Structural Magnetic Resonance Imaging(sMRI)images exhibit a higher number of channel dimensions.However,during the Position Embedding stage ofMulti Head Self Attention(MHSA),the coded information related to the channel dimension is disregarded.To tackle these issues,we propose theRepBoTNet-CESA network,an advanced AD-aided diagnostic model that is capable of learning local and global features simultaneously.It combines the advantages of CNN networks in capturing local information and Transformer networks in integrating global information,reducing computational costs while achieving excellent classification performance.Moreover,it uses the Cubic Embedding Self Attention(CESA)proposed in this paper to incorporate the channel code information,enhancing the classification performance within the Transformer structure.Finally,the RepBoTNet-CESA performs well in various AD-aided diagnosis tasks,with an accuracy of 96.58%,precision of 97.26%,and recall of 96.23%in the AD/NC task;an accuracy of 92.75%,precision of 92.84%,and recall of 93.18%in the EMCI/NC task;and an accuracy of 80.97%,precision of 83.86%,and recall of 80.91%in the AD/EMCI/LMCI/NC task.This demonstrates that RepBoTNet-CESA delivers outstanding outcomes in various AD-aided diagnostic tasks.Furthermore,our study has shown that MHSA exhibits superior performance compared to conventional attention mechanisms in enhancing ResNet performance.Besides,the Deeper RepBoTNet-CESA network fails to make further progress in AD-aided diagnostic tasks. 展开更多
关键词 ALZHEIMER CNN structural reparameterization multi head self attention computer aided diagnosis
下载PDF
Unified Description of the Three Stable Particles in Self-Action Allows Determination of Their Relative Masses
2
作者 Yair Goldin Halfon 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2024年第1期185-196,共12页
The Dirac equation γ<sub>μ</sub>(δ<sub>μ</sub>-eA<sub>μ</sub>)Ψ=mc<sup>2</sup>Ψ describes the bound states of the electron under the action of external potentials... The Dirac equation γ<sub>μ</sub>(δ<sub>μ</sub>-eA<sub>μ</sub>)Ψ=mc<sup>2</sup>Ψ describes the bound states of the electron under the action of external potentials, A<sub>μ</sub>. We assumed that the fundamental form of the Dirac equation γ<sub>μ</sub>(δ<sub>μ</sub>-S<sub>μ</sub>)Ψ=0 should describe the stable particles (the electron, the proton and the dark-matter-particle (dmp)) bound to themselves under the action of their own potentials S<sub>μ</sub>. The new equation reveals that self energy is consequence of self action, it also reveals that the spin angular momentum is consequence of the dynamic structure of the stable particles. The quantitative results are the determination of their relative masses as well as the determination of the electromagnetic coupling constant. 展开更多
关键词 Electron in self Action Electron-Dark-Matter Particle Mass Ratio Analytic Description Dark-Matter-Particle
下载PDF
Effect of Diabetes Self-Management Education on Glycaemic Control in Sudanese Adults with Type 2 Diabetes
3
作者 Sahar Moawia Balla Elnour Tayseer Abdelmotalib Ahmed Taha +8 位作者 Haiam Abdalla Wadatalla Ziryab Zainelabdin Mohamed Elmahdi Marwah Isam Abdulmajeed Mohammedahmed Rowa Abdelmonem Sidig Hamadto Nahla Yousif Osman Mohammed Saeed Omnia Mubarak Saad Abdallah Sulafa Abdelbagi Mustafa Ahmed Hanady Abdelhameed Ahmed Mohamed Sarah Khalil Fathi Khalil 《Journal of Biosciences and Medicines》 2024年第3期316-327,共12页
Research Background: The high prevalence of diabetes in Sudan, estimated at 16%, highlights the importance of effective health education in diabetes management. Diabetes self-management education has been identified a... Research Background: The high prevalence of diabetes in Sudan, estimated at 16%, highlights the importance of effective health education in diabetes management. Diabetes self-management education has been identified as a crucial tool in enhancing the knowledge, attitudes, and abilities necessary for self-management among individuals with diabetes. Aim: To assess the impact of diabetes self-management education on medication adherence and glycemic control in Sudanese adults with type 2 diabetes before and 3 months after the DSME intervention. Method: The study was conducted in Sudan between September 2022 and March 2023, it was an interventional, one-group, pre- and post-test study that aimed to assess the impact of diabetes self-management education (DSME) on medication adherence and diabetes control in Sudanese adults with type 2 diabetes. The research was conducted in primary health care centers in six cities in Sudan and involved 244 participants. The data entry and statistical analysis were conducted using the Statistical Package for Social Sciences version 27.0. A paired t test was used for analysis. Results: The study included 244 participants, 67% of whom were males. The age mean ± SD was 48.6 ± 9.3 years, and 85.3% of participants were married. Age at onset of diabetes mean ± SD was 40.60 ± 7.81 years;44.6% had diabetes for less than 5 years;and 84.1% had a positive family history of diabetes mellitus. The levels of poor, low, and partial adherence to medication decreased by 8.2%, 4%, and 20.6%, respectively, after the intervention. The levels of good and high medication regime adherence increased by 13% and 19.8%, respectively;BMI decreased by 1.1 ± 0.73 kg/m<sup>2</sup> (p = 0.005). The fasting blood sugar decreased by 69 ± 32.9 mg/dl (p = 0.049), and the glycated hemoglobin decreased by 1.21 ± 0.28% (p = 0.001). Conclusions: The findings of this study reinforce the importance of patient education in improving glycemic control and enhancing self-management behaviors. Patient education plays a critical role in enhancing glycemic control and self-management behaviors. It is essential for healthcare providers to adopt a patient-centered approach, taking into account the individual's beliefs, attitudes, and knowledge about their illness and treatment. Overcoming these challenges necessitates a comprehensive approach, including enhancing healthcare professionals’ knowledge and communication skills, offering accessible and culturally sensitive diabetes education programs, and addressing barriers to resources and support for self-management. 展开更多
关键词 SUDAN ADHERENCE Intervention EDUCATION self-MANAGEMENT Diabetes
下载PDF
基于BERT-SELFATT-CNN模型的垃圾邮件分类方法
4
作者 龚红仿 赵富荣 罗容容 《湖南文理学院学报(自然科学版)》 CAS 2024年第2期14-18,70,共6页
针对传统垃圾邮件分类方法中使用静态词向量不能解决一词多义、长序列信息特征提取不足等问题,提出了一种基于BERT-SELFATT-CNN模型的垃圾邮件分类方法。使用动态文本表示方法BERT对邮件内容进行预训练,并生成带有上下语义信息的词向量... 针对传统垃圾邮件分类方法中使用静态词向量不能解决一词多义、长序列信息特征提取不足等问题,提出了一种基于BERT-SELFATT-CNN模型的垃圾邮件分类方法。使用动态文本表示方法BERT对邮件内容进行预训练,并生成带有上下语义信息的词向量,经过能够并行计算的自注意力机制层计算词与词之间的相似度去挖掘句子长距离信息,将生成的隐藏层向量输入到CNN网络提取向量局部特征。在中文垃圾邮件数据集上与已有模型进行对比实验,结果表明该模型在精确度、召回率和F1值上均有提高,模型训练速度也得到提升。 展开更多
关键词 垃圾邮件 BERT 自注意力层 CNN 文本分类
下载PDF
Research Progress on Self-Efficacy Level of Patients with Type 2 Diabetes Mellitus and Its Influencing Factors
5
作者 Peiling Li Juanjuan Guo 《Open Journal of Preventive Medicine》 2024年第5期79-89,共11页
Self-efficacy plays an important role in the management of type 2 diabetes mellitus (T2DM) patients, and it runs through the whole process of diabetes treatment, which is conducive to controlling and delaying the occu... Self-efficacy plays an important role in the management of type 2 diabetes mellitus (T2DM) patients, and it runs through the whole process of diabetes treatment, which is conducive to controlling and delaying the occurrence and development of complications, as well as improving the quality of life of patients. This paper mainly describes the concept of self-efficacy, the current situation of self-efficacy of diabetic patients at home and abroad, the functional aspects and their influencing factors, so as to take relevant measures on how to improve self-efficacy. It aims to provide a theoretical basis for the development of self-efficacy interventions for patients with type 2 diabetes mellitus. 展开更多
关键词 Type 2 Diabetes self-EFFICACY Influencing Factors Measures
下载PDF
Practice of Glycemic Self-Monitoring in Diabetic Patients Followed at the Endocrinology Department of Donka University Hospital in Guinea
6
作者 Mamadou Dian Mamoudou Diallo Mamadou Mansour Diallo +10 位作者 Mamadou Chérif Diallo Alpha Mamadou Diallo Kadija Dieng Abdoul Mazid Diallo Mody Abdoulaye Barry Kadidiatou Bah El’Hadj Zainoul Bah Mamadou Alpha Diallo Ibrahima Condé Ousmane Kourouma Amadou Kaké 《Open Journal of Endocrine and Metabolic Diseases》 2024年第2期33-38,共6页
Diabetes is a chronic pathology whose evolution is marked by micro and macroangiopathic complications. Optimal management can prevent the onset of complications and improve patients’ quality of life. Objectives: To d... Diabetes is a chronic pathology whose evolution is marked by micro and macroangiopathic complications. Optimal management can prevent the onset of complications and improve patients’ quality of life. Objectives: To determine the frequency of self-monitoring of blood glucose and to describe the errors found during self-monitoring in diabetic patients followed at the Endocrinology Department of Donka University Hospital in Guinea. Materials and methods: Descriptive cross-sectional study carried out between August and September 2020 involving diabetic patients followed up at the Endocrinology and Diabetology Department of the Donka National Hospital, CHU Conakry. Results: A total of 301 patients were enrolled, with an average age of 44.24 ± 21.01 years. 64.12% were female. Type 2 diabetes predominated in 64% of cases. The mean duration of diabetes was 6.14 ± 4.67 years, and 75.08% of patients lived in urban areas. Patients were on insulin in 36.21% of cases, insulin and biguanides (26.25%), hypoglycemic sulfonamide and biguanides (19.27%) and biguanides in 18.27% of cases. The frequency of self-monitoring of blood glucose was 43%, and 38% of patients made errors, notably reusing lancets (60%), not checking the expiration date (55.65%) and not washing their hands (48%). Conclusion: This study shows that self-monitoring of blood glucose is not performed by the majority of patients. Numerous errors were identified during blood glucose testing. Continued therapeutic education on the use of blood glucose meters will help empower patients and improve their quality of life. 展开更多
关键词 self-Monitoring of Blood Glucose DIABETES Conakry University Hospital
下载PDF
Decision-Making and Management of Self-Care in Persons with Traumatic Spinal Cord Injuries: A Preliminary Study
7
作者 Paul E. Plonski Jasmin Vassileva +5 位作者 Ryan Shahidi Paul B. Perrin William Carter Lance L. Goetz Amber Brochetti James M. Bjork 《Journal of Behavioral and Brain Science》 2024年第2期47-63,共17页
Patients and physicians understand the importance of self-care following spinal cord injury (SCI), yet many individuals with SCI do not adhere to recommended self-care activities despite logistical supports. Neurobeha... Patients and physicians understand the importance of self-care following spinal cord injury (SCI), yet many individuals with SCI do not adhere to recommended self-care activities despite logistical supports. Neurobehavioral determinants of SCI self-care behavior, such as impulsivity, are not widely studied, yet understanding them could inform efforts to improve SCI self-care. We explored associations between impulsivity and self-care in an observational study of 35 US adults age 18 - 50 who had traumatic SCI with paraplegia at least six months before assessment. The primary outcome measure was self-reported self-care. In LASSO regression models that included all neurobehavioral measures and demographics as predictors of self-care, dispositional measures of greater impulsivity (negative urgency, lack of premeditation, lack of perseverance), and reduced mindfulness were associated with reduced self-care. Outcome (magnitude) sensitivity, a latent decision-making parameter derived from computationally modeling successive choices in a gambling task, was also associated with self-care behavior. These results are preliminary;more research is needed to demonstrate the utility of these findings in clinical settings. Information about associations between impulsivity and poor self-care in people with SCI could guide the development of interventions to improve SCI self-care and help patients with elevated risks related to self-care and secondary health conditions. 展开更多
关键词 Spinal Cord Injury self-CARE DECISION-MAKING PARAPLEGIA Impulsive Behavior Health Care
下载PDF
Edge-Federated Self-Supervised Communication Optimization Framework Based on Sparsification and Quantization Compression
8
作者 Yifei Ding 《Journal of Computer and Communications》 2024年第5期140-150,共11页
The federated self-supervised framework is a distributed machine learning method that combines federated learning and self-supervised learning, which can effectively solve the problem of traditional federated learning... The federated self-supervised framework is a distributed machine learning method that combines federated learning and self-supervised learning, which can effectively solve the problem of traditional federated learning being difficult to process large-scale unlabeled data. The existing federated self-supervision framework has problems with low communication efficiency and high communication delay between clients and central servers. Therefore, we added edge servers to the federated self-supervision framework to reduce the pressure on the central server caused by frequent communication between both ends. A communication compression scheme using gradient quantization and sparsification was proposed to optimize the communication of the entire framework, and the algorithm of the sparse communication compression module was improved. Experiments have proved that the learning rate changes of the improved sparse communication compression module are smoother and more stable. Our communication compression scheme effectively reduced the overall communication overhead. 展开更多
关键词 Communication Optimization Federated self-Supervision Sparsification Gradient Compression Edge Computing
下载PDF
基于DCNN网络及Self-Attention-BiGRU机制的轴承剩余寿命预测
9
作者 刘森 刘美 +2 位作者 贺银超 韩惠子 孟亚男 《机电工程》 CAS 北大核心 2024年第5期786-796,共11页
深度神经网络在剩余寿命预测(RUL)领域得到了广泛的应用。传统的滚动轴承寿命预测模型存在预测精确度较低、鲁棒性较弱的问题。为了进一步提升预测模型的精确度以及鲁棒性,提出了一种融合深度卷积神经网络(DCNN)、双向门控循环单元(BiG... 深度神经网络在剩余寿命预测(RUL)领域得到了广泛的应用。传统的滚动轴承寿命预测模型存在预测精确度较低、鲁棒性较弱的问题。为了进一步提升预测模型的精确度以及鲁棒性,提出了一种融合深度卷积神经网络(DCNN)、双向门控循环单元(BiGRU)以及自注意力机制(Self-Attention)三种模块的滚动轴承剩余使用寿命预测模型。首先,利用DCNN网络对原始振动信号的时域特征、频域特征进行了提取;然后,使用不确定量化的方法对提取到的特征进行了评价和筛选,利用筛选过后的特征构建了新的替代特征集;最后,利用Self-Attention-BiGRU网络对轴承的剩余使用寿命进行了预测,并在IEEE PHM2012数据集上进行了验证。实验结果表明:相较于BiGRU、GRU和BiLSTM三种模型的预测结果,基于DCNN及Self-Attention-BiGRU方法的预测结果最优,两项误差值:平均绝对误差(MAE)、均方根误差(RMSE)最低,其中工况一的一号轴承RUL预测的MAE值相较于BiGRU、GRU以及BiLSTM网络分别下降了7.0%、7.4%和6.5%,RMSE值相较于其他三种模型分别下降了7.6%、8.4%和6.9%,预测的Score值最高,分值为0.985。通过不同数据集的划分,证明了该方法在轴承RUL预测时的强鲁棒性。实验结果验证了基于DCNN网络及Self-Attention-BiGRU模型在轴承剩余使用寿命预测中的有效性。 展开更多
关键词 滚动轴承 剩余使用寿命 双向门控循环单元 不确定量化 自注意力机制 深度卷积神经网络 预测与健康管理
下载PDF
Performance Study of a Self-Excitation Dual Stator Winding Induction Generator for Renewable Distributed Generation Systems
10
作者 Faris Hamoud Mamadou Lamine Doumbia Ahmed Cheriti 《Smart Grid and Renewable Energy》 2016年第6期197-215,共20页
Renewable power generation is a suitable technology used to deliver energy locally to customers especially in remote regions. Wind energy based on induction generator situates in a foreground position in the total ene... Renewable power generation is a suitable technology used to deliver energy locally to customers especially in remote regions. Wind energy based on induction generator situates in a foreground position in the total energy produced using renewable sources. In the last few decades, a new self- excitation generator was based on multi-stator induction strongly emerges. This article presents a systematic modelling, a detailed analysis and the performance analysis of self-excitation dual stator winding induction generator (SE-DSWIG). The modelling of the SE-DSWIG was done with taking in account the common mutual leakage inductance between stators and the magnetizing inductance, which played a principal role in the stabilization of the output voltage in the steady state. The generator feeds the end user emulated by an inductive-resistive load. In order to simulate the weather conditions’ variation, a step change of the prime mover speed was applied on the SE-DSWIG. A passive series and shunt compensator was used to mitigate the voltage sag and swell appeared in the power system due to wind variation and the lack of reactive power consumed by the inductive load. 展开更多
关键词 Magnetizing Inductance Magnetizing Current Voltage Mitigation self-excitation Passive Compensator
下载PDF
Three-Dimensional Multi-Phase Microscopic Simulation of Service Life of Recycled Large Aggregate Self-Compacting Concrete
11
作者 Jing Li Lina Gao +3 位作者 Libo Liu Liao Zhang Jianhua Zheng Jing Gao 《Journal of Materials Science and Chemical Engineering》 2024年第4期126-135,共10页
Recycled large aggregate self-compacting concrete (RLA-SCC) within multiple weak areas. These weak areas have poor resistance to chloride ion erosion, which affects the service life of RLA-SCC in the marine environmen... Recycled large aggregate self-compacting concrete (RLA-SCC) within multiple weak areas. These weak areas have poor resistance to chloride ion erosion, which affects the service life of RLA-SCC in the marine environment. A three-dimensional multi-phase mesoscopic numerical model of RLA-SCC was established to simulate the chloride ions transportation in concrete. Experiments of RLA-SCC immersing in chloride solution were carried out to verify the simulation results. The effects of recycled large aggregate (RLA) content and RLA particle size on the service life of concrete were explored. The results indicate that the mesoscopic numerical simulation results are in good agreement with the experimental results. At the same depth, the closer to the surface of the RLA, the greater the chloride ion concentration. The service life of RLA-SCC in marine environment decreases with the increase of RLA content. Compared with the service life of 20% content, the service life of 25% and 30% content decreased by 20% and 42% respectively. Increasing the particle size of RLA can effectively improve the service life of RLA-SCC in chloride environment. Compared with the service life of 50 mm particle size, the service life of 70 mm and 90 mm increased by 61% and 163%, respectively. . 展开更多
关键词 Recycled Large Aggregate self-Compacting Concrete Mesoscopic Mode Chloride Ion Diffusion Numerical Analysis
下载PDF
The Impact of Simulation Education on Self-Efficacy in Pre-Registration Nursing Students
12
作者 Ahmed A. Hakami Aisha Hussin Rabie +2 位作者 Sultan Ghormallah M. Alzahrani Faisal Mohammed Alnakhilan Khalid Awaidhalharbi 《Open Journal of Nursing》 2024年第1期51-76,共26页
This literature review primarily aims to explore and synthesise the previous studies in simulation education research conducted over the past five years related to the effects of simulation training on the self-effica... This literature review primarily aims to explore and synthesise the previous studies in simulation education research conducted over the past five years related to the effects of simulation training on the self-efficacy of undergraduate pre-registration nursing students. The second aim of this study is to explore additional outcome variables that were examined in the previous studies. Five electronic databases were searched systematically. These databases were MEDLINE, CINAHL Plus, Scopus, Embase and PsycINFO. The PICO model was employed to identify the search terms, with a thesaurus being used to provide synonyms. Reference lists of relevant articles were examined and hand searches of journals were also undertaken. The quality of each study was assessed using the Simulation Research Rubric (SRR). A total of 11 studies were included. All studies explored the impact of simulation education on undergraduate pre-registration nursing. Six studies explored nursing students’ competence and performance and two papers examined their critical thinking. Problem solving, learning motivation, communication skills and knowledge acquisition were examined once. The majority of studies indicated that simulation training has a positive impact on pre-registration nursing students’ self-efficacy and other outcome variables. Furthermore, the study results indicate that simulation training is more dependable than traditional training, and students were extremely satisfied with the simulation training. However, most of the studies included in this review had several gaps, including study design, sample size and dissimilarities between the scales used. Further research with large samples, reliable and valid instruments, and outcomes measures (such as critical thinking and transferability of skills) is required to provide better insight into the effectiveness of simulation in undergraduate nursing education. . 展开更多
关键词 Simulation Education self-EFFICACY Pre-Registration Nursing Students Clinical Skills Undergraduate Nursing Education Teaching Techniques DECISION-MAKING
下载PDF
联合Self-attention与Axial-attention的机场跑道裂缝分割 被引量:1
13
作者 李海丰 范天啸 +2 位作者 黄睿 侯谨毅 桂仲成 《郑州大学学报(理学版)》 CAS 北大核心 2023年第4期30-38,共9页
机场跑道裂缝形态多样、方向各异、长短不一且粗细不均,通常不具有统计规律。现有的各类裂缝分割算法难以在此类复杂场景中落地。针对上述问题,提出了联合self-attention与axial-attention的机场跑道裂缝分割网络(CSA-net),通过引入自... 机场跑道裂缝形态多样、方向各异、长短不一且粗细不均,通常不具有统计规律。现有的各类裂缝分割算法难以在此类复杂场景中落地。针对上述问题,提出了联合self-attention与axial-attention的机场跑道裂缝分割网络(CSA-net),通过引入自注意力模块、轴向注意力模块、可变形卷积模块,提取裂缝的局部特征和全局语义特征。通过transformer decoder还原特征图的原始尺寸,融合了不同尺度间的分割结果,保留尽可能多的细节信息,使得CSA-net有更好的分割精度。在机场跑道实拍的数据集上进行的测试表明,针对裂缝的像素级分割指标F1-score达到了78.91%,高于目前各类裂缝分割算法。 展开更多
关键词 人工智能 CSA-net 自注意力 机场跑道裂缝分割 轴向注意力 特征融合
下载PDF
Averaging Analysis of Self-Excited Motion of a Quasi-Axisymmetrical Gyrostat
14
作者 薛纭 陈立群 《Journal of Shanghai University(English Edition)》 CAS 2002年第2期125-129,共5页
The averaging analysis was carried out to study the motion of a quasi axisymmetrical gyrostat under a small magnitude self excited control torque. The common approach to investigating the problem of rigid body rot... The averaging analysis was carried out to study the motion of a quasi axisymmetrical gyrostat under a small magnitude self excited control torque. The common approach to investigating the problem of rigid body rotation under the action of a small torque known in the body frame was described. Using this approach, the problem (Grammel's problem for the case of small torque) that is maintaining the angular velocity of a quasi axisymmetrical gyrostat using a control torque quadratic in the angular velocity was solved. 展开更多
关键词 GYROSTAT self excited motion averaging method phase trajectories.
下载PDF
Saturation influence of control voltage on maglev stationary self-excited vibration 被引量:3
15
作者 李金辉 李杰 余佩倡 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第8期1954-1960,共7页
This work addresses the saturation influence of control voltage on the occurring of self-excited vibration of maglev vehicle-bridge interaction system, which greatly degrades the stability of the levitation control, d... This work addresses the saturation influence of control voltage on the occurring of self-excited vibration of maglev vehicle-bridge interaction system, which greatly degrades the stability of the levitation control, decreases the ride comfort, and restricts the cost of the whole system. Firstly, the interaction model of vehicle-bridge system is developed. Based on the interaction model, the relationship between the control voltage and vibration frequency is solved. Then, the variation of the effective direct component and fundamental harmonic are discussed. Furthermore, from the perspective of energy transmission between the levitation system and bridge, the principle underlying the self-excited vibration is explored, and the influence on the stability is discussed. Finally, in terms of the variation of the characteristic roots, the influence is analyzed further and some conclusions are obtained. This study provides a theoretical guidance for mastering the self-excited vibration problems. 展开更多
关键词 自激振动 控制电压 磁悬浮列车 饱和 相互作用模型 耦合系统 磁悬浮车 悬浮控制
下载PDF
THEORY AND EXPERIMENTAL STUDY OF THE SELF-EXCITED OSCILLATION PULSED JET NOZZLE 被引量:28
16
作者 LiaoZhenfang LiJun +3 位作者 ChenDeshu DengXiaogang TangChuanlin ZhangFenghua 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2003年第4期379-383,共5页
Comparing with usual continuous jet nozzle, the self-excited oscillationpulsed jet nozzle SEOPJN) can make jet generate a higher peak of pressure and larger scouringvolume. And it can make jet increase the effective s... Comparing with usual continuous jet nozzle, the self-excited oscillationpulsed jet nozzle SEOPJN) can make jet generate a higher peak of pressure and larger scouringvolume. And it can make jet increase the effective standoff distance, too. The basic theories of theSEOPJN are introduced. Some experimental results are shown. According to the results, using tricornbits assembled the SEOPJN to drill oil well, the ROP increases by 8 percent approx 77 percent, andthe rates of the footage for tricorn bit increases by 6.7 percent approx 44.0 percent. 展开更多
关键词 self-excited oscillation pulsed jet NOZZLE BIT Point vortex
下载PDF
Self-excited vibration problems of maglev vehicle-bridge interaction system 被引量:11
17
作者 李金辉 李杰 +1 位作者 周丹峰 余佩倡 《Journal of Central South University》 SCIE EI CAS 2014年第11期4184-4192,共9页
The self-excited vibration problems of maglev vehicle-bridge interaction system were addressed, which greatly degrades the stability of the levitation control, decreases the ride comfort, and restricts the cost of the... The self-excited vibration problems of maglev vehicle-bridge interaction system were addressed, which greatly degrades the stability of the levitation control, decreases the ride comfort, and restricts the cost of the whole system. Firstly, the coupled model containing the quintessential parts was built, and the mechanism of self-excited vibration was explained in terms of energy transmission from levitation system to bridge. Then, the influences of the parameters of the widely used integral-type proportion and derivation(PD) controller and the delay of signals on the stability of the interaction system were analyzed. The result shows that the integral-type PD control is a nonoptimal approach to solve the self-excited vibration completely. Furthermore, the differential-type PD controller can guarantee the passivity of levitation system at full band. However, the differentiation of levitation gap should be filtered by a low-pass filter due to noise of gap differentiation. The analysis indicates that a well tuned low-pass filter can still keep the coupled system stable. 展开更多
关键词 相互作用系统 自激振动 振动问题 车桥 磁浮 PD控制器 低通滤波器 悬浮控制
下载PDF
HIGH-ORDER SELF-EXCITED VIBRATION INDUCED BY DRY FRICTION BETWEEN TWO ELASTIC STRUCTURES——VIBRATION MECHANISM OF THE CHINESE CULTURE RELIC DRAGON WASHBASIN 被引量:5
18
作者 刘习军 王大钧 +3 位作者 陈予恕 张丽 黄清华 李俊宝 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2001年第4期340-347,共8页
Combining theoretical and experimental modal analyses on self-excited vibration induced by dry friction between two elastic structures, we can explain the high-order sell-excited vibration phenomenon in which water dr... Combining theoretical and experimental modal analyses on self-excited vibration induced by dry friction between two elastic structures, we can explain the high-order sell-excited vibration phenomenon in which water droplets spurt from fourteen or twelve areas of the Chinese culture relic dragon washbasin when it is rubbed with hands, and clarify the mechanism of the singular high-order self-excited vibration. The experimental modes and the practical measured results are presented for a special dragon washbasin. The theoretical results agree well with the experimental ones. 展开更多
关键词 modal analysis fluid-solid coupling self-excited vibration
下载PDF
Mechanism of the self-excited oscillation pipeline flocculator 被引量:1
19
作者 邓晓刚 《Journal of Chongqing University》 CAS 2006年第1期13-15,共3页
This paper presents the research on the dynamic mechanism of flocculation based on the characteristcs of turbulent flow. The shearing force and the centrifugal force transferred by the vortex are the main forces to ca... This paper presents the research on the dynamic mechanism of flocculation based on the characteristcs of turbulent flow. The shearing force and the centrifugal force transferred by the vortex are the main forces to cause collision of flocculated grains in water and the shearing force is the primary one. Based on this mechanism, a new type of self-excited oscillation pipeline flocculator is designed. 展开更多
关键词 絮凝作用 自激振荡 涡流 絮凝器
下载PDF
Diabetes self-management education:Benefits and challenges
20
作者 Ibironke Cecilia OJO Elizabeth Olufunmilayo OJO Simeo Kayode OLUBIYI 《Journal of Integrative Nursing》 2023年第2期93-101,共9页
Diabetes mellitus has spread throughout many nations of the world and is now a serious threat.A lack of patient self‑management has been linked to this drain on global health.The consequences of diabetic patients’poo... Diabetes mellitus has spread throughout many nations of the world and is now a serious threat.A lack of patient self‑management has been linked to this drain on global health.The consequences of diabetic patients’poor self‑management have increased a variety of complications and lengthened hospital stays.Poor information and skill acquisition have been linked to poor self‑management.Participating in a co‑operative approach known as diabetes self‑management education will help diabetes patients who want to successfully self‑manage their condition and any associated conditions.Information is one of the most important components of a diabetes management strategy.In conclusion,numerous studies have shown that patients with diabetes have poor self‑management skills and knowledge in all areas,making training in diabetes self‑management necessary to minimize the complications that may result from diabetes mellitus among the patients.This review discussed the severity of diabetes mellitus,diabetes self‑management,and the benefits and challenges of diabetes self‑management,which may aid individuals in understanding the significance of diabetes self‑management and how it relates to diabetes self‑care. 展开更多
关键词 DIABETES diabetes self‑care diabetes self‑management diabetes self‑management education and support EDUCATION
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部