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铸造 1990年第6期39卷 41-43页

作者： r.prasad 夏仁凯

本文介绍了用超声技术测定铸铁的一些参数及评价其质量。就连续铸造而言,已用超声C型扫描技术测定铸坯的枝晶结构,这是控制连续铸造凝固过程的重要手段之一。

关键词：铸件质量测定超声波技术

PULPING STUDIES OF WHEAT STrAW USING SODA AND SODA -ANTHrAQUINONE PrOCESSES

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PULPING STUDIES OF WHEAT STRAW USING SODA AND SODA -ANTHRAQU...

relativistic electron acceleration by surface plasma waves excited with high intensity laser pulses

1988国际非木材纤维制浆造纸会议

作者： rAVI MOHAN r.prasad r.YADAV A.K.rAY Institute of Paper Technology Saharanpur-247001 INDIA Institute of Paper Technology Saharanpur-247001 INDIA Institute of Paper Technology Saharanpur-247001 INDIA Institute of Paper Technology Saharanpur-247001 INDIA

＜正＞Soda-Anthraquinone process,a non-sulphur pulping process of fibrous materials,involves soda cooking in presence of small amount of Anthraquinone or its derivatives. This results in improved yield with less rejects without affecting any quality of *** though the effect of Anthraquinone on pulping of hard and softwood are extensively reported in literature, the information on non-woody fibres,specially for Wheat straw are extremely limited. As Wheat straw is now increasingly used in. Indian mills,it will be of immense potential to elucidate the optimal parameters in pulping of Wheat straw from operational point of these *** no correlations are available between input and output variables or kinetics of soda/soda-Anthraquinone pulping of Wheat straw. An attempt has been made in this present investigation to identify the effect of different pulping parameters on the degree of cooking of Wheat straw experimentally in the laboratory. The range of all possible input and output variables are examined in the light of normal industrial operation in terms of delignification. Based on the data Important kinetic parameters such as H-factor,specific reaction rate,and activation energy are evaluated for both soda and soda-Anthraquinone pulping *** pulp properties like screened yield, rejects,residual lignin,fibre fractionation,unbleached pulp-strength properties are also evaluated From detailed experimental studies,the main conclusions can be drawn as follows: The addition of Anthraquinone brings about 4-5 percent increase in yield,a significant decrease of Kappa number and lignin . content of pulp but no appreciable change in pentosan content. 10-13 percent active alkali might be taken as optimum for wheat straw *** optimum time and temperature at the bulk delignification stage for straw pulping are found to be 2 hours and 393K respectively with approximately 88 percent delignification. 423K with 1 hour cooking time can also be proper operationa

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High Power Laser Science and Engineering 2020年第2期8卷 40-49页

作者： X.M.Zhu r.prasad M.Swantusch B.Aur A.A.Andreev O.Willi M.Cerchez Institut fur Laser und Plasmaphysik Heinrich-Heine-Universität DüsseldorfUniversitätsstr.1Düusseldorf40225Germany National Astronomical Observatories/Nanjing Institute of Astronomical Optics and Technology Chinese Academy of SciencesNanjing 210042China CAS Key Laboratory of Astronomical Optics and Technology Nanjing Institute of Astronomical Optics and TechnologyNanjing 210042China Saint Petersburg State University 7-9 Universitetskaya Nab.Saint Petersburg199034Russia ELI-ALPS Dugonics ter.13H 6722SzegedHungary

The process of high energy electron acceleration along the surface of grating targets(GTs)that were irradiated by a relativistic,high-contrast laser pulse at an intensity I=2.5×10^20 W/cm^2 was *** experimental results demonstrate that for a GT with a periodicity twice the laser wavelength,the surface electron flux is more intense for a laser incidence angle that is larger compared to the resonance angle predicted by the linear *** electron beam with a peak charge of∼2.7 nC/sr,for electrons with energies>1.5 MeV,was *** simulations carried out with parameters similar to the experimental conditions also show an enhanced electron flux at higher incidence angles depending on the preplasma scale length.A theoretical model that includes ponderomotive effects with more realistic initial preplasma conditions suggests that the laser-driven intensity and preformed plasma scale length are important for the acceleration *** predictions closely match the experimental and computational results.

关键词： laser-driven electron sources relativistic plasmas structured targets surface electrons

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可持续的地表自然资源管理

中国水土保持 2002年第7期 15-16页

作者： B.L.Gajja J.C.Tiwari r.prasad Central Arid Zone research Institute Central Soil Salinity Research Institure Jodhpur342003Karnal(India)132001

Fabrication of micrometre-sized periodic gratings in free-standing metallic foils for laser-plasma experiments

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High Power Laser Science and Engineering 2022年第1期10卷 17-31页

作者： C.C.Gheorghiu M.Cerchez E.Aktan r.prasad F.Yilmaz N.Yilmaz D.Popa O.Willi V.Leca Extreme Light Infrastructure-Nuclear Physics Horia Hulubei National Institute for Physics and Nuclear Engineering077125 MagureleRomania Institut fur Laser-und Plasmaphysik Heinrich-Heine-Universitat40225 DiisseldorfGermany

Engineered targets are expected to play a key role in future high-power laser experiments calling for joined, extensive knowledge in materials properties, engineering techniques and plasma physics. In this work, we propose a novel patterning procedure of self-supported 10 μm thick Au and Cu foils for obtaining micrometre-sized periodic gratings as targets for high-power laser applications. Accessible techniques were considered, by using cold rolling, electronbeam lithography and the Ar-ion milling process. The developed patterning procedure allows efficient control of the grating and foil surface on large area. Targets consisting of patterned regions of 450 μm × 450 μm, with 2 μm periodic gratings, were prepared on 25 mm × 25 mm Au and Cu free-standing foils, and preliminary investigations of the microtargets interacting with an ultrashort, relativistic laser pulse were performed. These test experiments demonstrated that,in certain conditions, the micro-gratings show enhanced laser energy absorption and higher efficiency in accelerating charge particle beams compared with planar thin foils of similar thickness.

关键词： laser driven plasmas on structured targets metallic foils micro-grating patterned targets

The distribution of parotid gland neoplasms in a veteran population

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World Journal of Otorhinolaryngology-Head and Neck Surgery 2021年第4期7卷 285-290页

作者： Adnan S.Hussaini Navin r.prasad Edina Paal Eshetu A.Tefera Sonya Malekzadeh Jessica H.Maxwell MedStar Georgetown University Hospital Department of OtolaryngologyHead and Neck SurgeryWashingtonDCUSA Georgetown University School of Medicine WashingtonDCUSA Washington DC Veterans Affairs Medical Center WashingtonDCUSA The George Washington University Department of PathologyWashington DCUSA MedStar Health research Institute-Department of Biostatistics and Biomedical Informatics HyattsvilleMDUSA

Objective:Salivary gland tumors account for 6%-8%of head and neck neoplasms with the parotid gland as the most common primary *** adenomas(PA)are considered the most common benign parotid gland neoplasms,followed by Warthin tumors(WT).The goal of this study was to investigate the distribution of parotid gland neoplasms among a United States veteran ***:retrospective chart ***:Washington DC Veterans Affairs Medical ***:Veterans who underwent fine needle aspiration(FNA)for a parotid gland mass from 2000 to 2018 were *** records were reviewed for gender,age,tobacco use,surgery date,and pathology *** outcome measures:Changes in the distribution of parotid neoplasms and tobacco use over an 18-year ***:Of 141 patients with parotid gland masses,86.5%(n=122)were benign,9.9%(n=14)were malignant,and 3.5%(n=5)were *** benign tumors,WT accounted for the majority at 51.6%,followed by PA at 40.2%.When stratified by decade(2000-2009 and 2010-2018),the proportion of WT compared to all other benign and malignant neoplasms increased from 31.6%to 53.6%,whereas the proportion of PA decreased from 36.8%to 33.3%.The rate of tobacco use was unchanged at approximately 32.0%among our cohort from 2000 to ***:Among our cohort of veteran patients,WT was the most common benign parotid tumor and has increased in incidence over the last two decades despite an unchanged smoking rate.

关键词： Parotid neoplasm Warthin tumor Pleomorphic adenoma Tobacco Head and neck cancer Veteran

Design of Power System Stabilizer for DFIG-based Wind Energy Integrated Power Systems Under Combined Influence of PLL and Virtual Inertia Controller

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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 524-534页

作者： Balakrushna Sahu Bibhu prasad Padhy Department of Electrical Engineering Indian Institute of Technology RoparPunjab140001India

Wind energy systems (WESs) based on doubly-fed induction generators (DFIGs) have enormous potential for meeting the future demands related to clean energy. Due to the low inertia and intermittency of power injection, a WES is equipped with a virtual inertial controller (VIC) to support the system during a frequency deviation event. The frequency deviation measured by a phase locked loop (PLL) installed on a point of common coupling (PCC) bus is the input signal to the VIC. However, a VIC with an improper inertial gain could deteriorate the damping of the power system, which may lead to instability. To address this issue, a mathematical formulation for calculating the synchronizing and damping torque coefficients of a WES-integrated single-machine infinite bus (SMIB) system while considering PLL and VIC dynamics is proposed in this paper. In addition, a power system stabilizer (PSS) is designed for wind energy integrated power systems to enhance electromechanical oscillation damping. A small-signal stability assessment is performed using the infinite bus connected to a synchronous generator of higher-order dynamics integrated with a VIC-equipped WES. Finally, the performance and robustness of the proposed PSS is demonstrated through time-domain simulation in SMIB and nine-bus test systems integrated with WES under several case studies.

关键词： Doubly-fed induction generator(DFIG) virtual inertia controller(VIC) phase locked loop(PLL) small-signal analysis synchronizing/damping torque synchronous generator power system stabilizer(PSS)

A Pair of Pseudo-differential Operators Involving Index Whittaker Transform in L_(2)^(a) (r_(+);m_(a)(x)dx)

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Acta Mathematica Sinica,English Series 2024年第6期40卷 1420-1430页

作者： Jeetendrasingh MAAN Akhilesh prasad Department of Mathematics and Computing Indian Institute of Technology(Indian School of Mines)Dhanbad-826004India

Pseudo-differential operators(PDO)Q(x,L_(a,x))and Q(x,L_(a,x))involving the index Whittaker transform are *** for these operators in Hilbert space L_(2)^(a)(r+;m_(a)(x)dx)are obtained.A symbol classΩis *** product an... 详细信息

关键词： Pseudo-differential operator index Whittaker transform confluent hypergeometric functions Hilbert space

Design of a Multi-Stage Ensemble Model for Thyroid Prediction Using Learning Approaches

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Intelligent Automation & Soft Computing 2024年第1期39卷 1-13页

作者： M.L.Maruthi prasad r.Santhosh Department of Computer Science and Engineering Faculty of EngineeringKarpagam Academy of Higher EducationCoimbatoreTamil NaduIndia

This research concentrates to model an efficient thyroid prediction approach,which is considered a baseline for significant problems faced by the women *** major research problem is the lack of automated model to attain earlier *** existing model fails to give better prediction ***,a novel clinical decision support system is framed to make the proper decision during a time of *** stages are followed in the proposed framework,which plays a substantial role in thyroid *** steps include i)data acquisition,ii)outlier prediction,and iii)multi-stage weight-based ensemble learning process(MS-WEL).The weighted analysis of the base classifier and other classifier models helps bridge the gap encountered in one single classifier *** classifiers aremerged to handle the issues identified in others and intend to enhance the prediction *** proposed model provides superior outcomes and gives good quality prediction *** simulation is done in the MATLAB 2020a environment and establishes a better trade-off than various existing *** model gives a prediction accuracy of 97.28%accuracy compared to other models and shows a better trade than others.

关键词： Thyroid machine learning pre-processing classification prediction rate

A novel control strategy of a variable-speed doubly-fed-induction-generator-based wind energy conversion system

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CLEAN ENErGY 2024年第1期8卷 153-170页

作者： Mohapatra, Shibani prasad Dash, Pradipta Kishore Siksha O Anusandhan Deemed Univ Dept Elect Engn Bhubaneswar 751030 Odisha India Siksha O Anusandhan Deemed Univ Multidisciplinary Res Cell Bhubaneswar 751030 Odisha India

This paper aims to address the issue of control of a variable-speed wind turbine based on doubly-fed induction generators. In this work, an effort is made to extract the maximum efficiency from a doubly-fed induction generator-based variable-speed wind turbine by controlling the rotor current. In the first step, a maximum power point tracking technique is used to extract the maximum power from the turbine. Then a stator-flux-oriented vector control strategy is employed to control the rotor-side current. Subsequently, a grid voltage vector-oriented control strategy is used to control the grid-side system of the grid-connected generator. Considering the nonlinearity and parameter uncertainty of the system, an active disturbance rejection controller with a sliding-mode-based extended-state observer is developed for the above-mentioned control strategies. Furthermore, the stability of the controller is tested and the performance of the controller is compared with the classical proportional-integral controller based on disturbance rejection, robustness and tracking capability in a highly non-linear wind speed variation scenario. Modelling, control and comparison are conducted in the MATLAB (r)/Simulink (r) environment. Finally, a real-time hardware set-up is presented using the dSPACE ds-1104 r&D processing board to validate the control scheme. From the result of the experiments, it is seen that the proposed controller takes 10-15 control cycles to settle to its steady-state values, depending on the control loop, whereas the conventional proportional-integral controller takes 60-75 control cycles. As a result, the settling time for the proposed control scheme is shorter than that of the proportional-integral controller. The maximum efficiency is extracted from a doubly-fed induction generator-based variable-speed wind turbine by controlling the rotor current. A maximum power point tracking technique is used in combination with a stator-flux-oriented vector control strate

关键词： doubly-fed induction generator variable-speed wind turbine vector control active disturbance rejection controller stability analysis NONLINEAr CONTrOL DFIG TUrBINE