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Machine Learning Application for Prediction of Sapphire Crystals Defects 被引量:1
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作者 Yulia Vladimirovna Klunnikova Maxim Vladimirovich Anikeev +1 位作者 Alexey Vladimirovich Filimonov ravi kumar 《Journal of Electronic Science and Technology》 CAS CSCD 2020年第1期1-9,共9页
We investigate the impact of different numbers of positive and negative examples on machine learning for sapphire crystals defects prediction. We obtain the models of crystal growth parameters influence on the sapphir... We investigate the impact of different numbers of positive and negative examples on machine learning for sapphire crystals defects prediction. We obtain the models of crystal growth parameters influence on the sapphire crystal growth. For example, these models allow predicting the defects that occur due to local overcooling of crucible walls in the thermal node leading to the accelerated crystal growth. We also develop the prediction models for obtaining the crystal weight, blocks, cracks, bubbles formation, and total defect characteristics. The models were trained on all data sets and later tested for generalization on testing sets, which did not overlap the training set.During training and testing, we find the recall and precision of prediction, and analyze the correlation among the features. The results have shown that the precision of the neural network method for predicting defects formed by local overcooling of the crucible reached 0.94. 展开更多
关键词 DEFECTS MACHINE LEARNING SAPPHIRE CRYSTALS
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汽车行业加速产品创新流程的技术——CAE技术 被引量:2
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作者 ravi kumar 苏喜兰 《CAD/CAM与制造业信息化》 2002年第7期14-16,共3页
关键词 汽车行业 产品创新流程 CAE 计算机仿真
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Herbal remedies,vaccines and drugs for dengue fever:Emerging prevention and treatment strategies
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作者 Rinku Rozera Surajpal Verma +2 位作者 ravi kumar Anzarul Haque Anshul Attri 《Asian Pacific Journal of Tropical Medicine》 SCIE CAS 2019年第4期147-152,共6页
Dengue fever is a disease that is caused by five dengue virus(DENV) serotypes. It is endemic in more than 128 countries. Millions of people are affected by this disease. But still, there is no specific treatment avail... Dengue fever is a disease that is caused by five dengue virus(DENV) serotypes. It is endemic in more than 128 countries. Millions of people are affected by this disease. But still, there is no specific treatment available till now to combat it. Some of the preventive measures using plant extracts showed certain promising ovicidal activity against Aedes aegypti. There are some vaccines as preventive measure and antiviral agents to cure the dengue fever, which are under clinical trials but their results have not been reported or approved yet. Dengvaxia is the only licensed vaccine to prevent dengue fever in some South American countries, but it is not approved by other regulatory authorities worldwide. Scientific research has been going on to find a permanent cure for dengue fever, but till now, no successful invention has been done. There are some general treatments for dengue patient by employing analgesics and fluid replacement; however, specific treatment is needed to overcome the lethal effect of dengue fever. Since this disease has affected millions of people and not much invention has been made in this field; therefore, advancement in dengue therapy is required for the safety and well-being of dengue patients. Herein we collectively describe the different chemotherapeutics agents, alternative methods like vaccines and antiviral agents to prevent and cure this lethal disease. Furthermore, the future perspective for the treatment of dengue is discussed in this review. 展开更多
关键词 DENGUE FEVER Plant EXTRACTS Vaccines and ANTIVIRAL agents
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Magnetizations and magneto-transport properties of Ni-doped PrFeO_3 thin films
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作者 Feroz A.Mir S.K.Sharma ravi kumar 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第4期608-615,共8页
The present study reports the magnetizations and magneto-transport properties of PrFel_xNixO3 thin films grown by pulsed laser ablation technique on LaA103 snbstrates. From DC M/H plots of these films, weak ferromagne... The present study reports the magnetizations and magneto-transport properties of PrFel_xNixO3 thin films grown by pulsed laser ablation technique on LaA103 snbstrates. From DC M/H plots of these films, weak ferromagnetism or ferrimagnetism behaviors are observed. With Ni substitution, reduction in saturation magnetization is also seen. With Ni doping, variations in saturation field (Hs), coercive field (Hc), Weiss temperature (0), and effective magnetic moment (Pelf) are seen. A small change of magnetoresitance with application of higher field is observed. Various essential parameters like density of state (Nf) at Fermi level, Mott's characteristic temperature (To), and activation energy (Ea) in the presence of and in the absence of magnetic field are calculated. The present observed magnetic properties are related to the change of Fe-O bond length (causing an overlap between the oxygen p orbital and iron d orbital) and the deviation of the Fe-O-Fe angle from 180~. Reduction of magnetic domain after Ni doping is also explored to explain the present observed magnetic behavior of the system. The influence of doping on various transport properties in these thin films indicates a distortion in the lattice structure and single particle band width, owing to stress-induced reduction in unit cell volume. 展开更多
关键词 thin films magnetization FERROMAGNETISM FERRIMAGNETISM magneto-transport and distortion
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Processing and characterization of polymer precursor derived silicon oxycarbide ceramic foams and compacts 被引量:1
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作者 Srinivasan NEDUNCHEZHIAN ravindran SUJITH ravi kumar 《Journal of Advanced Ceramics》 SCIE CAS 2013年第4期318-324,共7页
This work focused on the fabrication of silicon oxycarbide ceramic(SiOC)foams as well as dense compacts using poly(hydridomethylsiloxane)(PHMS)as a polymer precursor.The room-temperature cross-linking of PHMS was achi... This work focused on the fabrication of silicon oxycarbide ceramic(SiOC)foams as well as dense compacts using poly(hydridomethylsiloxane)(PHMS)as a polymer precursor.The room-temperature cross-linking of PHMS was achieved by the addition of 1,4-diazabicyclo[2.2.2]octane(DABCO)with the release of hydrogen gas as a by-product.This resulted in self-blowing of the polymer precursor at room temperature and thereby offered the possibility of producing SiOC foams without the need of any external blowing agents.We also reported the fabrication of crack-free silicon oxycarbide compacts by cold compaction and pyrolysis route using polyvinyl alcohol(PVA)as a processing additive.Cylindrical-shaped pellets were pyrolysed at 1300℃in argon atmosphere with a ceramic yield of approximately 85%.Increased resistance to phase separation and crystallization up to 1400℃was attributed to the presence of large volume fraction of free carbon in the material which was confirmed by Raman spectroscopy. 展开更多
关键词 silicon oxycarbide FOAMS 1 4-diazabicyclo[2.2.2]octane(DABCO) self-blown polymer poly(hydridomethylsiloxane)(PHMS)
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Transition-metal catalyzed asymmetric reactions under continuous flow from 2015 to early 2020 被引量:4
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作者 Jingyuan Liao Shilong Zhang +7 位作者 Zesheng Wang Xiao Song Dongliang Zhang ravi kumar Jian Jin Peng Ren Hengzhi You Fen-Er Chen 《Green Synthesis and Catalysis》 2020年第2期121-133,共13页
During last two decades,transition-metal catalyzed asymmetric reactions under continuous flow system have attracted a widespread attention.With its prominent advantages including higher safety and efficiency,precise c... During last two decades,transition-metal catalyzed asymmetric reactions under continuous flow system have attracted a widespread attention.With its prominent advantages including higher safety and efficiency,precise control,better heat/mass transfer,easier scale-up and better sustainability,it has impressed both the academia and related industries.However,comparing with the prosperous development of transition-metal catalyzed asymmetric reactions in batch,utilization of this type of chemistry under continuous flow is still at an early stage.To inspire more potential industrial application and further studies of this chemistry in flow,this review sum-marized the recent advances of transition-metal catalyzed asymmetric reactions under continuous flow.Moreover,we further discussed the encountered challenges including reactor engineering,catalyst design,catalyst deacti-vation,pressure drop,clogging,side reactions etc.,as well as their corresponding solutions and achievements in this mini-review. 展开更多
关键词 Transition-metal catalyst ASYMMETRIC Continuous flow Carbon-carbon bond formation HYDROGENATION Carbon-heteroatom bond formation Oxidation
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扭带式换热器水热关联的机器学习辅助建模
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作者 Jyoti Prakash Panda Bipin kumar +2 位作者 Anil kumar Patil Manoj kumar ravi kumar 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2023年第1期148-157,共10页
本文介绍了机器学习(ML)算法在带扭带插件的换热器传热关联(如努塞尔数和摩擦系数)建模中的应用.采用换热器在不同雷诺数(Re)、扭转比(t)、穿孔率(p)和不同扭带数(n)下的实验数据进行相关建模.在数据驱动的代理建模中使用了三种机器学... 本文介绍了机器学习(ML)算法在带扭带插件的换热器传热关联(如努塞尔数和摩擦系数)建模中的应用.采用换热器在不同雷诺数(Re)、扭转比(t)、穿孔率(p)和不同扭带数(n)下的实验数据进行相关建模.在数据驱动的代理建模中使用了三种机器学习算法:多项式回归(PR)、随机森林(RF)和人工神经网络(ANN).为了保证模型的通用性,对ML模型的超参数进行了优化,分析了不同ML算法的性能参数(如R 2和MAE).结果表明,在不同的测试数据集上,人工神经网络对传热系数的预测优于PR和RF的预测.基于本文分析内容,对未来数据驱动的传热关联建模工作和类似研究提出了建议. 展开更多
关键词 机器学习 数据驱动 测试数据集 辅助建模 多项式回归 超参数 穿孔率
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