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Chinese Journal of Aeronautics 2023年第5期36卷 33-40页

作者： Jörg SCHLÜTER Dan ZHAO abhishek SARKAR School of Engineering Deakin UniversityWaurn Ponds 3216Australia College of Engineering University of CanterburyChristchurch 8041New Zealand School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingapore

A better understanding of the mixing behavior of excited turbulent mixing layers is critical to a number of aerospace *** studies of excited turbulent mixing layers focused on single frequency excitation or the excitation with fundamental and its second harmonic *** is a lack of detailed studies on applying low and higher frequency *** this study,we have performed large-eddy simulations of periodically excited turbulent mixing *** excitation consists of a fundamental frequency and its third *** have used phase-averaging to identify the vortex structure and strength in the mixing layer,and we have studied the vortex *** different vortex paring mechanisms are observed depending on the phase shift between the two excitation *** influence of these two mechanisms on the mixing of a passive scalar is also *** is found that exciting the mixing layer with these low and high frequencies has initially an adverse influence on the mixing process;however,it improves the mixing further downstream of the splitter plate with the excitation using a phase shift ofΔφ=πshowing the best mixing *** present works shed lights on the fundamental vortex dynamics,and has great potential for aeronautical,automotive and combustion engineering applications.

关键词： Flow control Flow excitation Large eddy simulations Turbulent mixing layer Vortex dynamics

Advances in endobariatrics:past,present,and future

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Gastroenterology Report 2023年第1期11卷 140-150页

作者： abhishek Shenoy Allison R.Schulman Division of Gastroenterology and Hepatology University of MichiganMichigan MedicineAnn ArborMIUSA Department of Surgery University of MichiganMichigan MedicineAnn ArborMIUSA

The obesity epidemic in the USA and worldwide is well documented and continues to *** metabolic and bariatric therapies may offer a less invasive approach than surgical *** article will review advances in endobariatrics over the last several decades,addressing the past and current state of bariatric and metabolic *** and Drug Administration-cleared devices and interventions currently under investigation are described including gastric devices,gastric remodeling procedures,small-bowel devices,duodenal ablation,as well as procedures to address weight regain after bariatric *** studies evaluating gastric and duodenal combination therapy,adjunctive pharmacotherapy,as well as individualized precision-health algorithms are underway.

关键词： metabolic devices endoscopic sleeve gastroplasty obesity endobariatrics bariatric therapy

Performance analysis and design of MIMO-OFDM system using concatenated forward error correction codes

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Journal of Central South University 2017年第6期24卷 1322-1343页

作者： Arun Agarwal Saurabh N.mehta PhD Scholar School of Electrical EngineeringDepartment of Information TechnologyAMET UniversityTamil NaduChennai 603112India Department of Electronics and Telecommunication Engineering Vidyalankar Institute of TechnologyMumbai-400037MaharashtraIndia

This work investigates the performance of various forward error correction codes, by which the MIMO-OFDM system is deployed. To ensure fair investigation, the performance of four modulations, namely, binary phase shift keying(BPSK), quadrature phase shift keying(QPSK), quadrature amplitude modulation(QAM)-16 and QAM-64 with four error correction codes(convolutional code(CC), Reed-Solomon code(RSC)+CC, low density parity check(LDPC)+CC, Turbo+CC) is studied under three channel models(additive white Guassian noise(AWGN), Rayleigh, Rician) and three different antenna configurations(2×2, 2×4, 4×4). The bit error rate(BER) and the peak signal to noise ratio(PSNR) are taken as the measures of performance. The binary data and the color image data are transmitted and the graphs are plotted for various modulations with different channels and error correction codes. Analysis on the performance measures confirm that the Turbo + CC code in 4×4 configurations exhibits better performance.

关键词： bit error rate (BER) convolutional code (CC) forward error correction peak signal to noise ratio (PSNR) Turbo code

Preparation,crystallization,microstructure and dielectric properties of lead bismuth titanate borosilicate glass ceramics

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Journal of Advanced Ceramics 2014年第3期3卷 194-206页

作者： Chandkiram RGAUTAM abhishek MADHESHIYA Ranabrata MAZUMDER Advanced Glass and Glass Ceramic Research Laboratory Department of PhysicsUniversity of LucknowLucknow 226007India Department of Ceramic Engineering National Institute of TechnologyRouerkela 769008India

Various bulk and transparent glasses were prepared by rapid melt quenching technique in the glass system 55[(Pb_(x)Bi_(1-x))TiO_(3)]-44[2Si_(O)2B_(2)O_(3)]-La2O3(x=0-0.7).The X-ray diffraction(XRD)studies of the glass samples confirmed the amorphous *** differential thermal analyses(DTA)were carried out from room temperature to 900℃with a heating rate of 10℃/*** DTA patterns of the samples showed one or more exothermic sharp peaks shifting towards lower temperature side with increasing concentration of bismuth oxide(BiO).On the basis of DTA results,the solid solution of bismuth titanum oxide(Bi_(2)Ti_(2)O_(7))/lead bismuth titanium oxide(Pb3Bi4Ti6O21)was precipitated in borosilicate glassy matrix as a major *** glasses were subjected to 4 h and 8 h heat treatment schedules to convert into glass *** analysis of these glass ceramic samples showed that the major crystalline phase of the entire glass ceramic samples with 0≤x≤0.5 is found to have cubic crystal structure,while it is tetragonal for glass ceramic sample with x=*** scanning electron microscopy(SEM)micrographs indicated the uniform distribution of Bi_(2)Ti_(2)O_(7)and Pb3Bi4Ti6O21 crystallites in the glassy matrix.

关键词： lead bismuth titanate differential thermal analysis(DTA) crystallization scanning electron microscopy(SEM) dielectric behavior

Numerical Analysis of Phase Change and Container Materials for Thermal Energy Storage in the Storage Tank of Solar Water Heating System

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Journal of Thermal Science 2024年第2期33卷 408-421页

作者： SINGH Shailendra ANAND abhishek SHUKLA Amritanshu SHARMA Atul Non-Conventional Energy Laboratory Rajiv Gandhi Institute of Petroleum TechnologyJais Amethi229304India

This study evaluates the effectiveness of phase change materials(PCMs) inside a storage tank of warm water for solar water heating(SWH) system through the theoretical simulation based on the experimental model of *** et *** model is explained by five fundamental equations for the calculation of various parameters like the effectiveness of PCMs,the mass of hot water,total heat content,and duration of *** study simulated eleven PCMs to analyze their effectiveness like Sodium hydrogen phosphate dodecahydrate(SHPD),OM 37,N-Eicosane(NE),Lauric acid(LA),Paraffin wax(PW),OM 48,Paraffin wax C_(20-33)(PW-C20-33),Sodium acetate trihydrate(SAT),Palmitic acid(PA),Myristic acid(MA),and Stearic acid(SA).Among all PCMs,the SHPD has found the highest value of effectiveness factor of ***,it is the most recommended PCM for the storage tank of the SWH *** study also includes the melt fraction analysis of all enumerated PCMs corresponding to container materials of stainless steel,glass,aluminum mixed,tin,aluminum,and *** melt fraction analysis is performed by making a coding program in the FORTRAN programming *** the analysis,copper container material is found to have high melting rate for all PCMs so it is superior to other container materials.

关键词： theoretical model solar water heating system phase change material effectiveness factor melt fraction

Microsurgical varicocelectomy： a review

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Asian Journal of Andrology 2013年第1期15卷 56-60页

作者： Akanksha mehta Marc Goldstein Department of Urology and Center for Male Reproductive Medicine and Surgery Weill Cornell Medical College New York NY 10021 USA

Varicocelectomy is the most commonly performed surgical procedure for the treatment of male infertility. Although several different techniques for varicocele repair have been described in the literature, microsurgical varicocelectomy performed through a subinguinal or inguinal incision is recognized as the gold-standard approach for varicocelectomy, due to high success rates with minimal complications. Standard indications for varicocelectomy include palpable varicocele（s）, with one or more abnormal semen parameters, and, for the couple trying to conceive, in the setting of normal or correctable female infertility. However, varicocele repair is often recommended and undertaken for reasons other than infertility, including low serum testosterone, testicular pain, testicular hypotrophy and poor sperm DNA quality. This article reviews the technical aspects of microsurgical varicocelectomy, and its indications in adults and adolescents.

关键词： DNA fragmentation hypogonadism infertility microsurgical varicocelectomy orchalgia varicocele repair

Anti-arthritis activity of roots of Hemidesmus indicus ***.(Anantmul)in rats

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Asian Pacific Journal of Tropical Medicine 2012年第2期5卷 130-135页

作者： Alka mehta Neeraj K Sethiya Chetan mehta GB Shah Pharmacy Department Faculty of Technology and Engineering KalabhavanThe M.S.University of BarodaVadodara 390002(Gujarat)India Radiology Department SSG Hospital and Medical CollegeVadodara-390001(Gujarat)India KBIPER Gandhinagar-382023(Gujarat).India

Objective:To investigate the protective effects of hydroalcoholic and its fractions from roots of Hemidesmus indicus on arthritis in in vitro models of ***:Preliminary phytochemical analysis and thin-layer chromoatography were performed to analyze constituents of hydroalcoholic extract and its three fraction namely ethyl acetate fraction,chloroform fraction and residual fraction of mot of Hemidesmus *** rats models were established by Complete Freund’s *** parameters including paw edema,body weight,arthritic index,erythrocyte sedimentation rate,serum rheumatoid factor,serum C-reactive protein,serum nitrite level,and histopathology of synovial joints were *** was taken as positive ***:Rats treated with hydroalcoholic extract(450 mg/kg,p.o.),ethyl acetate (75 mg/kg,p.o.),chloroform(60 mg/kg,p.o) and residual fractions(270 mg/kg,p.o.),showed significant decrease in physical and biochemical parameters compared with arthritic model rats. Hydroalcoholic extract and its ethyl acetate fraction of Hemidesmus indicus showed significantly higher anti-arthritic activity than chloroform and residual *** analysis demonstrated that both of hydroalcoholic extract and its ethyl acetate fraction had comparable anti-arthritic activity with ***:The present study suggests that Hemidesmus indicus has protective activity against arthritis and the activity might be attributed to presence of terpenoid in hydroalcoholic extract,as well as in ethyl acetate fraction.

关键词： Arthritic Index Hemidesmus indicus Anti-inflammatory Phenolic Terpenoids

Effects of defects on the electronic properties of WTe_2 armchair nanoribbons

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Journal of Semiconductors 2014年第11期35卷 10-15页

作者： Bahniman Ghosh abhishek Gupta Bhupesh Bishnoi Microelectronics Research Center 10100Burnet RoadBldg.160University of Texas at AustinAustinTX78758USA Department of Electrical Engineering Indian Institute of Technology Kanpur

We have investigated the electronic properties of WTe2 armchair nanoribbons with defects. WTe2 nanoribbons can be categorized depending on the edge structure in two types： armchair and zigzag. WTe2 in its bulk form has an indirect band gap but nanoribbons and nanosheets of WTe2 have direct band gaps. Interestingly, the zigzag nanoribbon is metallic while the armchair nanoribbons are semiconducting. Thus they can find applications in device fabrication. Therefore, it is very important to study the effect of defects on the electronic properties of the armchair nanoribbons as these defects can impair the device properties and characteristics. We have considered defects such as： vacancy, rough edge, wrap, ripple and twist in this work. We report the band gap variation with these defects. We have also studied the change in band gap and total energy with varying degrees of wrap, ripple and twist.

关键词： electronic property WTe2 armchair nanoribbons defects

Laser Heated Emissive Probes Design and Development under National Fusion Program and Potential Measurement

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Chinese Physics Letters 2014年第12期31卷 74-78页

作者： mehta Payal SARMA Arun GHOSH Joydeep Venus International College of Technology Gandhinagar Gujarat India School of Advanced Sciences VIT University Chennai Vandalur-Kelambakkam Road Chennai 600127 India Institute for Plasma Research Bhat Gandhinagar 382428 Gujarat India

Emissive probes are the tools for the direct deter- mination of the plasma potential ~PL and they deliver a more reliable measure of φPL compared to the indi- rect measurements with cold Langmuir probes. The emissive probe works on the principle of compensating the well-known asymmetry of the I-V characteristic of a single cold Langmuir probe by an electron emission current from the probe into the plasma. In an ideal case, the saturated value of floating potential V（А,em） of a highly emissive probe should equal the plasma potential. A conventional emissive probe usu- ally consists of a loop of tungsten wire heated by an electric current passing through it. These conven- tional emissive probes containing an electric current- heated metal wire loop suffer a huge drawback when it comes to their lifetime. The metal wire used in these probes evaporates and subsequently breaks when heated with high current, leading to frequent replacements of these wires. When used in ultra high vacuum （UHV） plasma systems, frequent replacement of these wires requires frequent vacuum breaks in the plasma systems. In many plasma systems espe- cially in magnetized toroidal hot plasmas like toka- maks, where determination of the electric fields leads to a great deal of useful information, frequent breaking of the vacuum is impossible for changing the filament of the emissive probes. Hence, along with the other drawbacks of the conventional emissive probes such as limited emission current, bending in a magnetic field makes their use impractical in these plasma systems. The most suitable alternative is the emissive probes heated by a focused infra-red laser. Due to them having several advantages over the conventional emis- sive probes, laser heated emissive probes （LHEPs） are found to have more and more uses in plasma systems. The advantages of the LHEP are： longer lifetime （no filament breaking issues）, attainment of higher tem- perature without melting or evaporation and thus higher emissivi

关键词： Laser Heated Emissive Probes Design and Development un

Modeling phase equilibria of semiclathrate hydrates of CH_4,CO_2 and N_2 in aqueous solution of tetra-n-butyl ammonium bromide

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Journal of Natural Gas Chemistry 2012年第4期21卷 459-465页

作者： abhishek Joshi Prathyusha Mekala Jitendra S.Sangwai Petroleum Engineering Program Department of Ocean EngineeringIndian Institute of Technology MadrasChennai-600 036India

Semiclathrate hydrates of tetra-n-butyl ammonium bromide （TBAB） offer potential solution for gas storage, transportation, separation of flue gases and CO2 sequestration. Models for phase equilibria for these systems have not yet been developed in open literatures and thus require urgent attention. In this work, the first attempt has been made to model phase equilibria of semiclathrate hydrates of CH4, CO2 and N2 in aqueous solution of TBAB. A thermodynamic model for gas hydrate system as proposed by Chen and Guo has been extended for semiclathrate hydrates of gases in aqueous solution of TBAB. A correlation for the activity of water relating to the system temperature, concentration of TBAB in the system and the nature of guest gas molecule has been proposed. The model results have been validated against available experimental data on phase equilibria of semiclathrate hydrate systems of aqueous TBAB with different gases as guest molecule. The extended Chen and Guo＇s model is found to be suitable to explain the promotion effect of TBAB for the studied gaseous system such as, methane, carbon dioxide and nitrogen as a guest molecule. Additionally, a correlation for the increase in equilibrium formation temperature （hydrate promotion temperature, ATp） of semiclathrate hydrate system with respect to pure gas hydrate system has been developed and applied to semiclathrate hydrate of TBAB with several gases as guest molecules. The developed correlation is found to predict the promotion effect satisfactorily for the system studied.

关键词： gas hydrate phase equilibria semiclathrate hydrate tetra-n-butyl ammonium bromide (TBAB)