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Contact Stress Reliability Analysis Model for Cylindrical Gear with Circular Arc Tooth Trace Based on an Improved Metamodel

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 593-619页

作者： Qi Zhang Zhixin Chen Yang Wu Guoqi Xiang guang Wen Xuegang Zhang Yongchun Xie guangchun Yang School of Intelligent Manufacturing&Automobile Chengdu Industrial Vocational Technical CollegeChengdu610218China School of Intelligent Manufacturing Panzhihua UniversityPanzhihua617000China School of Electrical Engineering Chengdu Industry and Trade CollegeChengdu601165China School of Mechanical Engineering Sichuan UniversityChengdu601165China Chengdu Technological University Chengdu611730China

Although there is currently no unified standard theoretical formula for calculating the contact stress of cylindrical gears with a circular arc tooth trace(referred to as CATT gear),a mathematical model for determining the contact stress of CATT gear is essential for studying how parameters affect its contact stress and building the contact stress limit state equation for contact stress reliability *** this study,a mathematical relationship between design parameters and contact stress is formulated using the *** enhance the model’s accuracy,we propose a new hybrid algorithm that merges the genetic algorithm with the Quantum Particle Swarm optimization algorithm,leveraging the strengths of ***,the“parental inheritance+self-learning”optimization model is used to fine-tune the KrigingMetamodel’s *** this,amathematicalmodel for calculating the contact stress of Variable Hyperbolic Circular-Arc-Tooth-Trace(VH-CATT)gears using the optimized Kriging model was *** then examined how different gear parameters affect the VH-CATT gears’contact *** simulation results show:(1)Improvements in R2,RMSE,and RMAE.R2 rose from0.9852 to 0.9974(a 1.22%increase),nearing 1,suggesting the optimized Kriging Metamodel’s global error is ***,RMSE dropped from3.9210 to 1.6492,a decline of 57.94%.The global error of the GA-IQPSO-Kriging algorithm was also reduced,with RMAE decreasing by 58.69%from 0.1823 to 0.0753,showing the algorithm’s enhanced *** a comparison of ten experimental groups selected randomly,the GA-IQPSO-Kriging and FEM-based contact analysis methods were used to measure contact *** revealed a maximum error of 12.11667 MPA,which represents 2.85%of the real value.(2)Several factors,including the pressure angle,tooth width,modulus,and tooth line radius,are inversely related to contact *** descending order of their impact on the contact stress is:tooth line radius>modulus

关键词： CATT gear contact stress finite element method metamodel hybrid algorithm influencing factors

Study on How to Improve Tourism English Major Students’English Communicative Ability in Higher vocational college

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Journal of Literature and Art Studies 2024年第8期14卷 726-729页

作者： SHEN Hua-ying School of Digital and Cultural Tourism Sichuan Vocational and Technical CollegeSuining 629000China

Tourism English Major students’English communicative ability is very important for students’to promote professional *** is necessary for students to improve the commnunicative ability and It is one of the teachers’... 详细信息

关键词： communicative ability professional skills cultivate

Exposure to ephedrine attenuates Th1/Th2 imbalance underlying OVA-induced asthma through airway epithelial cell-derived exo-somal lnc-TRPM2-AS

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Chinese Journal of Natural Medicines 2024年第6期22卷 530-540页

作者： HU Yan WANG Mengqing XIE Jing JIAO Luojia DING Yi LUO Yinhe Department of Pediatrics The First Hospital of Hunan University of Chinese MedicineChangsha 410007China Hunan University of Chinese Medicine Changsha 410208China Department of Rehabilitation Medical CollegeChangsha Civil Affairs Vocational and Technical CollegeChangsha 410004Hunan ProvinceChina Teaching and Research Office of Chinese and Western Combination Hunan University of Chinese MedicineChangsha 410208China

Although various anti-inflammatory medications,such as ephedrine,are employed to manage cough-variant asthma,their underlying mechanisms are yet to be fully *** studies suggest that exosomes derived from airway epithelial cells(AECs)contain components like messenger RNAs(mRNAs),micro-RNAs(miRNAs),and long noncoding RNA(lncRNA),which play roles in the occurrence and progression of airway *** study investigates the influence of AEC-derived exosomes on the efficacy of ephedrine in treating cough-variant *** established a mouse model of asthma and measured airway resist-ance and serum inflammatory cell ***-time polymerase chain reaction(RT-qPCR),Western blotting,and enzyme-linked im-munosorbent assay(ELISA)analyses were used to assess gene and protein expression *** were isolated and *** immunoprecipitation(RIP)and RNA pull-down assays were conducted to examine the interaction between hnRNPA2B1 and *** the ovalbumin(OVA)-challenged mouse model,ephedrine treatment reduced inflammatory responses,air-way resistance,and Th1/Th2 cell *** from OVA-treated AECs showed elevated levels of lnc-TRPM2-AS1,which were diminished following ephedrine *** exosomal lnc-TRPM2-AS1 mediated the Th1/Th2 imbalance in CD4^(+)T cells,with its packaging into exosomes being facilitated by *** study unveils a novel mechanism by which ephedrine ameli-orates OVA-induced CD4^(+)T cell imbalance by suppressing AEC-derived exosomal *** findings could provide a theoretical framework for using ephedrine in asthma treatment.

关键词： Asthma Ephedrine Exosomal lnc-TRPM2-AS1 Th1/Th2 imbalance HnRNPA2B1 Airway epithelial cells

Effect of rare earth on primary carbides in H13 die steel and their addition method:a review

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Journal of Iron and Steel Research International 2024年第3期31卷 531-551页

作者： Jing-feng Wang Lin-zhu Wang Chao-yi Chen Xiang Wang Fei Zhao School of Materials and Metallurgy Guizhou UniversityGuiyang 550025GuizhouChina Zhengzhou Railway vocational and technical college Zhengzhou 450000HenanChina Guizhou Provincial University Key Laboratory of High Performance Battery Materials Guizhou UniversityGuiyang 550025GuizhouChina Shougang Guiyang Special Steel Co. Guiyang 550005GuizhouChina

Larger-sized primary carbides lead to stress concentration during the application of H13 hot-work die steel,resulting in microcracks and fatigue *** earth was usually added to modify the carbides and *** existing literature is reviewed on the effect of rare earth on primary carbides in H13 steel.A comprehensive review on the effect of rare earth on the characteristics of primary carbides,i.e.,number,size,morphology,and thermal stability in H13 steel,was *** precipitation mechanism and nucleation of primary carbides with rare earth were *** position and form of rare earth in steel and their effects on alloying elements segregation were *** addition techniques of rare earth in H13 steel were compared,and the prospects for other uncommon rare earth and emerging technology were *** on the current references,it can be known that adding rare earth facilitated refined and dispersed primary *** size of primary carbides would be reduced,and their morphology would be improved because the rare earth inclusions formed in H13 steel can act as nucleation cores forγ-Fe orδ-Fe,refining the dendritic ***,the number of primary carbides at grain boundaries would be significantly ***,rare earth had little impact on thermal *** nucleation of primary carbides tended to be inhibited due to the modification of inclusions by rare earth which were likely to be nucleation cores for primary *** earth had been reported to affect the mechanism and process of primary carbide ***,the addition of rare earth can inhibit the segregation of alloying elements and carbon diffusion by ***,laboratory experiments and theoretical calcu-lations need to be conducted to study the states and evolution of rare earth steels.

关键词： Rare earth H13 die steel Primary carbide Nucleation Dendritic structure

A Railway Fastener Inspection Method Based on Abnormal Sample Generation

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Computer Modeling in Engineering & Sciences 2024年第4期139卷 565-592页

作者： Shubin Zheng Yue Wang Liming Li Xieqi Chen Lele Peng Zhanhao Shang Higher vocational and technical college Shanghai University of Engineering ScienceShanghai200437China School of Urban Railway Transportation Shanghai University of Engineering ScienceShanghai201620China Shanghai Engineering Research Centre of Vibration and Noise Control Technologies for Rail Transit Shanghai University of Engineering ScienceShanghai201620China

Regular fastener detection is necessary to ensure the safety of ***,the number of abnormal fasteners is significantly lower than the number of normal fasteners in real *** supervised inspectionmethods have insufficient detection ability in cases of imbalanced *** solve this problem,we propose an approach based on deep convolutional neural networks(DCNNs),which consists of three stages:fastener localization,abnormal fastener sample generation based on saliency detection,and fastener state ***,a lightweight YOLOv5s is designed to achieve fast and precise localization of fastener ***,the foreground clip region of a fastener image is extracted by the designed fastener saliency detection network(F-SDNet),combined with data augmentation to generate a large number of abnormal fastener samples and balance the number of abnormal and normal ***,a fastener inspection model called Fastener ResNet-8 is constructed by being trained with the augmented fastener *** show the effectiveness of our proposed method in solving the problem of sample imbalance in fastener *** and quantitative comparisons show that the proposed F-SDNet outperforms other state-of-the-art methods in clip region extraction,reaching MAE and max F-measure of 0.0215 and 0.9635,*** addition,the FPS of the fastener state inspection model reached 86.2,and the average accuracy reached 98.7%on 614 augmented fastener test sets and 99.9%on 7505 real fastener datasets.

关键词： Railway fastener sample generation inspection model deep learning

Research advances in enhanced coal seam gas extraction by controllable shock wave fracturing

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International Journal of Coal Science & Technology 2024年第3期11卷 1-31页

作者： Chaojun Fan Hao Sun Sheng Li Lei Yang Bin Xiao Zhenhua Yang Mingkun Luo Xiaofeng Jiang Lijun Zhou college of Mining Liaoning Technical UniversityFuxin123000China college of Safety Science and Engineering Liaoning Technical UniversityFuxin123000China Energy Business Department Shanxi Lu’an Chemical GroupChangzhi046200China

With the continuous increase of mining in depth,the gas extraction faces the challenges of low permeability,great ground stress,high temperature and large gas pressure in coal *** controllable shock wave(CSW),as a new method for enhancing permeability of coal seam to improve gas extraction,features in the advantages of high efficiency,eco-friendly,and low *** order to better utilize the CSW into gas extraction in coal mine,the mechanism and feasibility of CSW enhanced extraction need to be *** this paper,the basic principles,the experimental tests,the mathematical models,and the on-site tests of CSW fracturing coal seams are reviewed,thereby its future research directions are *** on the different media between electrodes,the CSW can be divided into three categories:hydraulic effect,wire explosion and excitation of energetic materials by detonating *** the process of propagation and attenuation of the high-energy shock wave in coal,the shock wave and bubble pulsation work together to produce an enhanced permeability effect on the coal *** stronger the strength of the CSW is,the more cracks created in the coal is,and the greater the length,width and area of the cracks *** repeated shock on the coal seam is conducive to the formation of complex network fracture system as well as the reduction of coal seam strength,but excessive shock frequency will also damage the coal structure,resulting in the limited effect of the enhanced gas *** the influence of ground stress,the crack propagation in coal seam will be *** difference of horizontal principal stress has a significant impact on the shape,propagation direction and connectivity of the CSW induced *** permeability enhancement effect of CSW is affected by the breakage degree of coal *** shock wave is absorbed by the broken coal,which may hinder the propagation of CSW,resulting in a poor effect of permeability *** arranging two a

关键词： Controllable shock wave Permeability enhancement Gas extraction Basic principle Experimental test Mathematical models On-site test

Efficacy and safety of perioperative therapy for locally resectable gastric cancer:A network meta-analysis of randomized clinical trials

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World Journal of Gastrointestinal Oncology 2024年第3期16卷 1046-1058页

作者： Zi-Yu Kuang Qian-Hui Sun Lu-Chang Cao Xin-Yi Ma Jia-Xi Wang Ke-Xin Liu Jie Li Graduate college Beijing University of Traditional Chinese MedicineBeijing 100029China Oncology Department Guang’anmen HospitalChina Academy of Chinese Medical SciencesBeijing 100053China

BACKGROUND Gastric cancer(GC)is the fifth most commonly diagnosed malignancy worldwide,with over 1 million new cases per year,and the third leading cause of cancer-related *** To determine the optimal perioperative treatment regimen for patients with locally resectable *** A comprehensive literature search was conducted,focusing on phase II/III randomized controlled trials(RCTs)assessing perioperative chemotherapy and chemoradiotherapy in treating locally resectable *** R0 resection rate,overall survival(OS),disease-free survival(DFS),and incidence of grade 3 or higher nonsurgical severe adverse events(SAEs)associated with various perioperative regimens were analyzed.A Bayesian network meta-analysis was performed to compare treatment regimens and rank their *** Thirty RCTs involving 8346 patients were included in this *** XELOX plus neoadjuvant radiotherapy and neoadjuvant CF were found to significantly improve the R0 resection rate compared with surgery alone,and the former had the highest probability of being the most effective option in this *** plus adjuvant FLOT was associated with the highest probability of being the best regimen for improving *** to limited data,no definitive ranking could be determined for *** nonsurgical SAEs,FLO has emerged as the safest treatment *** This study provides valuable insights for clinicians when selecting perioperative treatment regimens for patients with locally resectable *** studies are required to validate these findings.

关键词： Gastric cancer Perioperative treatment Network meta-analysis Efficacy and safety

Construction of a Virtual Simulation Practice Teaching System of the Chemical Industry Under the Background of Integration of Production and Education

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Journal of Contemporary Educational Research 2024年第5期8卷 103-109页

作者： Lixia Wang Liu Guojun Branch Jiangsu United Vocational and Technical College ChangzhouChangzhou 213000Jiangsu ProvinceChina

With the development of the integration of production and education,chemical engineering and technology education is facing many new challenges and *** construction of a chemical virtual simulation practice teaching system under the background of integration of production and education aims to improve students’learning efficiency and innovation ability with the help of virtual simulation technology,so as to meet the needs of future industrial *** paper discusses the significance of the construction of the system,analyzes the difficulties and challenges that may be encountered in the construction process,and evaluates the effective strategies to strengthen the construction of the *** the introduction of virtual simulation technology,students can improve their practical skills and innovation ability,and better adapt to the development needs of industrialization and informatization.

关键词： Integration of production and education Chemical virtual simulation practice Teaching system

Design and optimization of the seed conveying system for belt-type highspeed corn seed guiding device

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International Journal of Agricultural and Biological Engineering 2024年第2期17卷 123-131页

作者： Yifei Li Wenqi Zhou Chengcheng Ma Zhaohua Feng Jinwu Wang Shujuan Yi Song Wang college of Engineering Northeast Agricultural UniversityHarbin 150030China college of Engineering Heilongjiang Bayi Agricultural UniversityDaqing 163000HeilongjiangChina Agricultural Engineering Department Qitaihe Vocational Technician CollegeQitaihe 154600HeilongjiangChina

Seeding is an important part of improving corn ***,seed guide tubes are mostly used as transport *** the existing seed guide tubes cannot meet the requirements or achieve the goal of fixing the seed falling trajectory.A seed collision phenomenon occurs ***,in response to the problems that the seeds and seed guide tube collide or bounce under high speed operation,which results in a lower sowing qualification rate and poor spacing uniformity,a seed receiving and conveying system comprising a belt-type high-speed corn seed guiding device was designed and optimized,to meet the needs of high-speed precision sowing operations and improve the spacing *** factors affecting the seed conveying performance were obtained by analyzing the mechanical properties of the seeds at various movement *** factors were the number of seed cavities between adjacent seeds,the forward speed,the height from the ground,and the installation *** factor simulation experiments were conducted by selecting the paddle spacing as the test factor and using the pass rate,reseeding rate,omission rate and coefficient of variation as the evaluation indexes to investigate the influence of the paddle spacing on the seed guide performance of the device and further determine the structural parameters of the paddle *** rotation combination tests of three factors and five levels were also conducted through bench *** the test outcomes were *** results indicated that the best results were obtained when the number of seed cavity intervals between adjacent seeds was 5.16,the installation angle was 79.40°,and the height from the ground was 31.84 *** this time,the qualified rate was 98.49%,the repeated sowing rate was 0.48%,the missed sowing rate was 1.03%,and the coefficient of variation was 6.80%.Experiments were used to validate the optimization results,and all of the obtained index data satisfied the criteria for accurate

关键词： corn high-speed sowing belt-type seed guide device test