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AZ31镁合金激光焊件的力学性能和应力腐蚀行为(英文)

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Transactions of Nonferrous metals Society of China 2011年第1期21卷 1-8页

作者： p.B.srinivasan S.RIEKEHR C.BLAWERT W.DIETZEL m.KO AK Institute of materials Research GKSS-Forschungszentrum Geesthacht GmbH Geesthacht D-21502Germany

采用Nd-YAG激光对AZ31 Hp镁合金进行激光自熔焊接。显微组织分析表明,使用或不使用填料(焊料)AZ61镁合金得到的激光焊接接头的平均晶粒尺寸大约为12μm,显微硬度和拉伸强度与母材相近。然而,慢应变速率拉伸表明,在ASTm D1384溶液中两种... 详细信息

采用Nd-YAG激光对AZ31 Hp镁合金进行激光自熔焊接。显微组织分析表明,使用或不使用填料(焊料)AZ61镁合金得到的激光焊接接头的平均晶粒尺寸大约为12μm,显微硬度和拉伸强度与母材相近。然而,慢应变速率拉伸表明,在ASTm D1384溶液中两种焊接接头的抗应力腐蚀性能比母材略差。可观察到应力腐蚀裂纹在焊缝金属萌生并向热影响区(HAZ)扩展。然而,在以AZ61镁合金为填料(焊料)获得的焊接接头中,观察到裂纹起源及扩展出现在热影响区(HAZ)。在慢应变速率拉伸试验中,由于试样表面暴露在腐蚀环境中,在氢氧化镁/氧化镁层形成局部损伤,从而导致应力腐蚀裂纹的生成。

关键词：镁合金激光焊接显微组织力学性能慢应变速率拉伸应力腐蚀裂纹断面分析

单层和双层二硫化钼化学气相沉积生长的动力学蒙特卡罗模拟研究（英文）

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物理化学学报 2019年第10期35卷 1119-1127页

作者：陈帅高峻峰 srinivasan Bharathi m. 张永伟新加坡科技研究局高性能计算研究院

通过化学气相沉积方法,可控合成所需层数的二硫化钼仍然是一个挑战。因此,建立一个能够定量预测单层和多层二硫化钼生长的理论模型,并为实验制备提供指导,是十分必要的。在本文中,我们建立了一个动力学蒙特卡罗模型,来预测单层和双层二... 详细信息

通过化学气相沉积方法,可控合成所需层数的二硫化钼仍然是一个挑战。因此,建立一个能够定量预测单层和多层二硫化钼生长的理论模型,并为实验制备提供指导,是十分必要的。在本文中,我们建立了一个动力学蒙特卡罗模型,来预测单层和双层二硫化钼的化学气相沉积生长。首先,我们提出了第一层和第二层的生长速率受吸附原子浓度分布的控制,以及紧凑三角形二硫化钼的生长过程为扭结成核和传播。其中,原子浓度是由吸附原子流量,吸附原子的有效寿命,生长温度,边的单位长度能量,单层和双层的单位面积结合能,成核准则决定的。扭结成核和传播是由锯齿边和扶手边附加原子所需的能量势垒决定的。然后,我们采用热力学理论准则对这些参数进行了标定。通过标定的动力学蒙特卡罗模型,我们发现第二层的生长速率与第一层的尺寸有很强的依赖性。随着第一层尺寸增加,第二层的生长速率呈单调递减趋势,甚至在第一层达到某个尺寸时,第二层的生长会被抑制。此外,我们还分析了不同生长温度和吸附原子流量下,双层二硫化钼的尺寸和形貌演化。在双层二硫化钼的整个生长过程中,第一层和第二层的形貌保持紧凑三角形,验证了扭结成核和传播模型的正确性。模拟结果表明,生长温度的升高或吸附原子流量的降低,促进了双层二硫化钼的生长,这与已报导的实验结果相吻合。生长温度升高使得第二层二硫化钼边缘的吸附原子浓度,随着远离第二层边缘的吸附原子浓度降低而相应降低,促进了双层二硫化钼的生长。同样,吸附原子流量降低减小了基体上的吸附原子浓度,降低了第一层远离边缘和靠近边缘的吸附原子浓度差,从而减缓了第一层的生长。第一层的生长减慢,减缓了第二层远离边缘和靠近边缘的吸附原子浓度差减小到零,从而促进双层二硫化钼的生长。为了更好地指导实验,我们进一步构建了双层二硫化钼生长的相图,可通过控制生长温度和吸附原子流量来实现或阻止双层二硫化钼的生长。因此,本工作不仅揭示了单层和双层二硫化钼生长所需的实验条件,而且为可控合成所需层数的二硫化钼提供了详细指导。

关键词：二硫化钼单层生长双层生长化学气相沉积动力学蒙特卡罗

Thermophoresis and Brownian motion effects on boundary layer flow of nanofluid in presence of thermal stratification due to solar energy

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Applied mathematics and mechanics(English Edition) 2012年第6期33卷 765-780页

作者： N.ANBUCHEZHIAN K.srinivasan K.CHANDRASEKARAN R.KANDASAmY Department of mechanical Engineering Sri Guru Institute of Technology Department of mechanical Engineering Anna University Department of mechanical Engineering R.M.K.Engineering College Research Centre for Computational mathematics Faculty of ScienceTechnology and Human DevelopmentUniversiti Tun Hussein Onn Malaysia

The problem of laminar fluid flow, which results from the stretching of a vertical surface with variable stream conditions in a nanofluid due to solar energy, is in- vestigated numerically. The model used for the nanofluid incorporates the effects of the Brownian motion and thermophoresis in the presence of thermal stratification. The sym- metry groups admitted by the corresponding boundary value problem are obtained by using a special form of Lie group transformations, namely, the scaling group of transfor- mations. An exact solution is obtained for the translation symmetrys, and the numerical solutions are obtained for the scaling symmetry. This solution depends on the Lewis number, the Brownian motion parameter, the thermal stratification parameter, and the thermophoretic parameter. The conclusion is drawn that the flow field, the temperature, and the nanoparticle volume fraction profiles are significantly influenced by these param- eters. Nanofluids have been shown to increase the thermal conductivity and convective heat transfer performance of base liquids. Nanoparticles in the base fluids also offer the potential in improving the radiative properties of the liquids, leading to an increase in the efficiency of direct absorption solar collectors.

关键词： solar radiation Brownian motion nanofluid thermophoresis thermalstratification

Effects of gadolinium addition on the microstructure and mechanical properties of mg–9Al alloy

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International Journal of minerals,metallurgy and materials 2017年第8期24卷 901-908页

作者： Lavish Kumar Singh Alok Bhadauria Amirthalingam srinivasan Uma Thanu Subramonia pillai Bellambettu Chandrasekhara pai Department of metallurgical and materials Engineering Indian Institute of Technology Kharagpur materials Science and Technology Division National Institute for Interdisciplinary Science and Technology

This research aims to study the significance of Gd addition(0wt%–2wt%) on the microstructure and mechanical properties of mg–9Al alloy. The effect of Gd addition on the microstructure was investigated via X-ray diffraction(XRD), optical microscopy, scanning electron microscopy(SEm), and transmission electron microscopy(TEm). The mg–9Al alloy contained two phases, α-mg and β-mg_(17)Al_(12). Alloying with Gd led to the emergence of a new rectangular-shaped phase, Al_2Gd. The grain size also decreased marginally upon Gd addition. The ultimate tensile strength and microhardness of mg–9Al alloy increased by 23% and 19%, respectively, upon 1.5wt% Gd addition. We observed that, although mg–9Al–2.0Gd alloy exhibited the smallest grain size(181 μm) and the highest dislocation density(5.1 × 10^(10) m^(-2)) among the investigated compositions, the mg–9Al–1.5Gd alloy displayed the best mechanical properties. This anomalous behavior was observed because the Al_2Gd phase was uniformly distributed and present in abundance in mg–9Al–1.5Gd alloy, whereas it was coarsened and asymmetrically conglomerated in mg–9Al–2.0Gd.

关键词： magnesium rare earth alloying gadolinium microstructure mechanical properties

In silico prediction of monovalent and chimeric tetravalent vaccines for prevention and treatment of dengue fever

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The Journal of Biomedical Research 2018年第3期32卷 222-236页

作者： Vijayakumar Subramaniyan Ramesh Venkatachalam prabhu srinivasan manogar palani Computational phytochemistry Laboratory p.G. and Research Department of Botany and microbiology A.V.V.M. Sri Pushpam College (Autonomous)

Reverse vaccinology method was used to predict the monovalent peptide vaccine candidate to produce antibodies for therapeutic purpose and to predict tetravalent vaccine candidate to act as a common vaccine to cover all the dengue virus serotypes. Envelope（E）-proteins of DENV-1-4 serotypes were used for vaccine prediction using NCBI,Uniprot/Swissprot, Swiss-prot viewer, VaxiJen V2.0, TmHmm, BCpREDS, propred-1, propred and mHC pred. Eproteins of DENV-1-4 serotypes were identified as antigen from which T cell epitopes, through B cell epitopes, were predicted to act as peptide vaccine candidates. Each selected T cell epitope of E-protein was confirmed to act as vaccine and to induce complementary antibody against particular serotype of dengue virus. Chimeric tetravalent vaccine was formed by the conjugation of four vaccines, each from four dengue serotypes to act as a common vaccine candidate for all the four dengue serotypes. It can be justifiably concluded that the monovalent 9-mer T cell epitope for each DENV serotype can be used to produce specific antibody against dengue virus and a chimeric common tetravalent vaccine candidate to yield a comparative vaccine to cover any of the four dengue virus serotype. This vaccine is expected to be highly immunogenic against dengue fever.

关键词： dengue serotypes dengue virus vaccine E-proteins mHC Ⅰ and Ⅱ

An Efficient Sound and Data Steganography Based Secure Authentication System

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Computers, materials & Continua 2021年第4期67卷 723-751页

作者： Debajit Datta Lalit Garg Kathiravan srinivasan Atsushi Inoue G.Thippa Reddy m.praveen Kumar Reddy K.Ramesh Nidal Nasser School of Computer Science and Engineering Vellore Institute of Technology(VIT)Vellore632014India Faculty of Information and Communication Technology University of MaltaMsidaMSD2080Malta School of Information Technology and Engineering Vellore Institute of Technology(VIT)Vellore632014India Department of Information Systems&Business Analytics Eastern Washington UniversitySpokaneWA99202USA Department of Computer Science Karnataka State Akkamahadevi Women’s UniversityVijayapuraIndia College of Engineering Alfaisal UniversityRiyadh1153Saudi Arabia

The prodigious advancements in contemporary technologies have also brought in the situation of unprecedented ***,the pin-based security system is an inadequate mechanism for handling such a *** reason is that hackers use multiple strategies for evading security systems and thereby gaining access to private *** research proposes to deploy diverse approaches for authenticating and securing a connection amongst two devices/gadgets via sound,thereby disregarding the pins’manual ***,the results demonstrate that the proposed approaches outperform conventional pin-based authentication or QR authentication ***,a random signal is encrypted,and then it is transformed into a wave file,after which it gets transmitted in a short burst via the device’s ***,the other device/gadget captures these audio bursts through its microphone and decrypts the audio signal for getting the essential data for ***,this model requires two devices/gadgets with speakers and a microphone,and no extra hardware such as a camera,for reading the QR code is *** first module is tested with realtime data and generates high scores for the widely accepted accuracy metrics,including precision,Recall,F1 score,entropy,and mutual information(mI).Additionally,this work also proposes a module helps in a secured transmission of sensitive data by encrypting it over images and other *** steganographic module includes two-stage encryption with two different encryption algorithms to transmit data by embedding inside a *** encryption algorithms and their combinations are taken for this system to compare the resultant file *** these systems engender high accuracies and provide secure connectivity,leading to a sustainable communication ecosystem.

关键词： Cyber-attacks signals privacy security organization encryption decryption authentication effective communication steganography

Rainfall partitioning in young clonal plantations Eucalyptus species in a subtropical environment,and implications for water and forest management

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International Soil and Water Conservation Research 2021年第3期9卷 474-484页

作者： Decio Oscar Cardoso Ferreto Josémiguel Reichert Rosane Barbosa Lopes Cavalcante Raghavan srinivasan Soils Department Universidade Federal de Santa Maria(UFSM).Avenida Romima 1000Santa MariaRSBrazil Instituto Tecnoldgico Vale.Rua Boaventura da Silva 955UmarizalBelemPABrazil Department of Ecology and Conservation Biology Texas A&M University(TAMU)534 John Kimbrough Blvd.Room 305College StationTXUSA

Different canopy characteristics of industrial eucalyptus may lead to differences in water evaporation and availability to *** study aims to understand rainfall partitioning in a young clonal plantation(age of 2-4.5 years)of three eucalyptus species by relating tree parameters:diameter at breast height,total height,and leaf area *** measured rainfall,throughfall,stemflow and litter interception,along with the tree *** eucalyptus trees had rainfall interception varying between 22 mm(for 178 mm of rainfall)and 42 mm(for 87 mm of te rainfall),throughfall between 106 mm(for 186 mm of rainfall)and 44 mm(for 74 mm of rainfall),and stemflow between 0.5 mm(for 92 mm of rainfall)and 1.4 mm(for 24 mm of rainfall).For the three species,rainfall interception varied between 12 and 48%,throughfall between 57 and 90%,and stemflow between 0.3 and 5.4%.The coefficient of determination between interception and rainfall was 0.76,indicating interception depends on other variables,possibly including antecedent rainfall,rainfall intensity,and *** decreased with a reduction in leaf area index caused by eucalyptus *** *** had 0.75 mm of throughfall per 1 mm of rainfall,whereas in *** and E saligna,these ratios were 0.71 and 0.68,*** in *** and *** had a higher positive relationship with the diameter at breast height of the trees,whereas in *** the highest relationship was with the *** results contribute to establishing management strategies,such as choosing suitable eucalyptus species to local climate,and to improve the synchronization of crop-demand versus soil-water-supply while maintaining streamflow to fulfill ecological and production needs.

关键词： Water balance Blue-green water Forest hydrology Rainfall interception Rainfall throughfall

Simulated mRI Artifacts:Testing machine Learning Failure modes

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Biomedical Engineering Frontiers 2022年第1期3卷 437-452页

作者： Nicholas C.Wang Douglas C.Noll Ashok srinivasan Johann Gagnon-Bartsch michelle m.Kim Arvind Rao Department of Computational medicine and Bioinformatics University of MichiganUSA Department of Biomedical Engineering University of MichiganUSA Department of Radiology University of MichiganUSA Department of Radiology Division of NeuroradiologyUniversity of MichiganUSA Rogel Cancer Center University of MichiganUSA Frankel Cardiovascular Center University of MichiganUSA Department of Statistics University of MichiganUSA Department of Radiation Oncology University of MichiganUSA

*** types of mRI artifacts,including acquisition and preprocessing errors,were simulated to test a machine learning brain tumor segmentation model for potential failure ***-world medical deployments of machine learning algorithms are less common than the number of medical research papers using machine *** of the gap between the performance of models in research and deployment comes from a lack of hard test cases in the data used to train a *** failure modes were simulated for a pretrained brain tumor segmentation model that utilizes standard mRI and used to evaluate the performance of the model under *** simulated mRI artifacts consisted of motion,susceptibility induced signal loss,aliasing,field inhomogeneity,sequence mislabeling,sequence misalignment,and skull stripping *** artifact with the largest effect was the simplest,sequence mislabeling,though motion,field inhomogeneity,and sequence misalignment also caused significant performance *** model was most susceptible to artifacts affecting the FLAIR(fluid attenuation inversion recovery)***,these simulated artifacts could be used to test other brain mRI models,but this approach could be used across medical imaging applications.

关键词： utilize stripping susceptibility

50种中药甲醇提取物对嗜水气单胞菌的体外抑菌及抗生物膜活性的评价

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药物评价研究 2023年第1期46卷 64-71页

作者：傅钰瑛陈小萌 srinivasan Ramanathan 李珍刘柱林向民福建船政交通职业学院安全与环境学院福建福州350007 福建农林大学生命科学学院福建省农业生态过程与安全监控重点实验室福建福州350002 漳州卫生职业技术学院福建漳州363000 海南大学生命与药物学院分子生物实验室海南海口570228

目的评价50种中药甲醇提取物对嗜水气单胞菌的体外抑菌效果以及抗生物膜生成活性。方法采取甲醇浸提的方法制备中药甲醇提取物,计算提取率;利用多功能酶标仪检测600 nm处的吸光度(A600)值测定各提取物(0.1、0.2、0.4、0.8、1.6、3.2 m... 详细信息

目的评价50种中药甲醇提取物对嗜水气单胞菌的体外抑菌效果以及抗生物膜生成活性。方法采取甲醇浸提的方法制备中药甲醇提取物,计算提取率;利用多功能酶标仪检测600 nm处的吸光度(A600)值测定各提取物(0.1、0.2、0.4、0.8、1.6、3.2 mg·mL^(-1))作用16 h对嗜水气单胞菌的抑菌率;结晶紫染色法结合多功能酶标仪测定各提取物的抗生物膜活性。结果苏木、白芍、侧柏叶等32种中药甲醇提取物对嗜水气单胞菌抑菌效果明显,其中苏木甲醇提取物的抑菌效果最显著,最大抑菌率达95.56%,起效质量浓度为0.1 mg·mL^(-1);石菖蒲、大青叶、广藿香等20种中药甲醇提取物明显抑制嗜水气单胞菌生物被膜的生成,其中白芍的最大抑制率达96.78%。结论夏枯草、野菊花、大青叶、赤芍、石菖蒲、地肤子、连翘、苏木、肉桂、女贞子、白芍、甘草、肉豆蔻、鸡血藤、乌药、莪术、侧柏叶17种中药对嗜水气单胞菌同时具有抑菌和抑制生物膜生长活性。

关键词：中药嗜水气单胞菌体外抑菌抗菌活性抗生物膜活性苏木白芍