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Position Dependent Spontaneous Emission Spectra of a Λ-Type Atomic System Embedded in a Defective Photonic Crystal

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Communications in Theoretical Physics 2012年第1期57卷 115-122页

作者： S.roshan Entezar Faculty of Physics University of TabrizTabrizIran

We investigate the position dependent spontaneous emission spectra of a A-type three-level atom with one transition coupled to the free vacuum reservoir and the other one coupled to a double-band photonic band gap reservoir with a defect mode in the band gap. It is shown that, for the atom at the defect location, we have a two-peak spectrum with a wide dark line due to the strong coupling between the atom and the defect mode. While, when the atom is far from the defect location （or in the absence of the defect mode）, the spectrum has three peaks with two dark lines due to the coupling between the atom and the photonic band gap reservoir with the largest density of states near the band edges. On the other hand, we have a four-peak spectrum for the atom at the space in between. Moreover, the average spontaneous emission spectra of the atoms uniformly embedded in high dielectric or low dielectric regions are described. It is shown that the atoms embedded in high （low） dielectric regions far from the defect location, effectively couple to the modes of the lower （upper） photonic band. However, the atoms embedded in high dielectric or low dielectric regions at the defect location, are coupled mainly to the defect modes. While, the atoms uniformly embedded in high （low） dielectric regions with a normal distance from the defect location, are coupled to both of defect and lower （upper） photonic band modes.

关键词： spontaneous emission defective photonic crystal dark line three-level atom

Regenerative engineering and bionic limbs

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Rare Metals 2015年第3期34卷 143-155页

作者： roshan James Cato T.Laurencin Institute for Regenerative Engineering University of Connecticut Health Center Raymond and Beverly Sackler Center for Biological Physical and Engineering SciencesUniversity of Connecticut Health Center Department of Orthopaedic Surgery University of Connecticut Health Center Connecticut Institute for Clinical and Translational Science Department of Chemical Materials and Biomolecular EngineeringUniversity of Connecticut

Amputations of the upper extremity are severely debilitating, current treatments support very basic limb movement, and patients undergo extensive physiotherapy and psychological counseling. There is no prosthesis that allows the amputees near normal function. With increasing number of amputees due to injuries sustained in accidents, natural calamities, and international conflicts, there is a growing requirement for novel strategies and new discov- eries. Advances have been made in technological, material, and in prosthesis integration where researchers are now exploring artificial prosthesis that integrate with the residual tissues and function based on signal impulses received from the residual nerves. Efforts are focused on challenging experts in different disciplines to integrate ideas and tech- nologies to allow for the regeneration of injured tissues,recording on tissue signals and feedback to facilitate responsive movements and gradations of muscle force. A fully functional replacement and regenerative or integrated prosthesis will rely on interface of biological process with robotic systems to allow individual control of movement such as at the elbow, forearm, digits, and thumb in the upper extremity. Regenerative engineering focused on the regen- eration of complex tissue and organ systems will be realized by the cross-fertilization of advances over the past 30 years in the fields of tissue engineering, nanotechnology, stem cell science, and developmental biology. The convergence of toolboxes crated within each discipline will allow interdis- ciplinary teams from engineering, science, and medicine to realize new strategies, mergers of disparate technologies, such as biophysics, smart bionics, and the healing power of the mind. Tackling the clinical challenges, interfacing the biological process with bionic technologies, engineering biological control of the electronic systems, and feedback will be the important goals in regenerative engineering over the next

关键词： Bionic Electrical stimulation Regenerativeengineering Muscle Nerve Prosthetic

Performance evaluation of nanofluid-based minimum quantity lubrication grinding of Ni-Cr alloy under the influence of CuO nanoparticles

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Advances in Manufacturing 2021年第4期9卷 580-591页

作者： roshan Lal Virdi Sukhpal Singh Chatha Hazoor Singh Department of Mechanical Engineering Punjabi UniversityPatialaIndia Yadavindra College of Engineering Guru Kashi Punjabi University CampusTalwandi SaboIndia

In machining processes,researchers are actively engaged in exploring minimum quantity lubrication(MQL)as a possible alternative to traditional flood cooling owing to economic and ecological *** search for ecologically safe lubricants has attracted the attention of scientists looking to use vegetable oil as a *** nanofluid MQL technique with biodegradable oils as the base is a relatively new method with the potential to replace mineral *** the present study,the grinding of Inconel-718 alloy was investigated using nanofluid MQL(NFMQL)with biodegradable oils as the *** are composed by dispersing 0.5%(mass fraction)and 1%(mass fraction)of CuO nanoparticles in vegetable *** surface morphology,G-ratio,forces,and grinding energy were examined under pure MQL,NFMQL,and dry and flood lubrication *** experimental results indicated that the nanofluid MQL significantly improved the machining *** to the polishing and rolling effect of nanoparticles on the tool work interface,a surface finish under a 0.5%(mass fraction)nanofluid was found to be better than pure MQL-dry and flood lubrication *** NFMQL technique with 1%(mass fraction)CuO nanoparticles with palm oil as the base helped in achieving a better evacuation of chips from the grinding zone,leading to a better surface finish with a high material removal rate along with less energy consumption compared to flood and dry grinding.

关键词： Minimum quantity lubrication(MQL) Nanoparticles Grinding Vegetable oils Inconel-718 alloy

Analysis of frequency shifting in seismic signals using Gabor-Wigner transform

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Earthquake Engineering and Engineering Vibration 2015年第4期14卷 715-724页

作者： roshan Kumar P.Sumathi Ashok Kumar Deaprtment of Earthquake Engineering IIT Roorkee Deaprtment of Electrical Engineering IIT Roorkee

A hybrid time-frequency method known as Gabor-Wigner transform (GWT) is introduced in this paper for examining the time-frequency patterns of earthquake damaged buildings. GWT is developed by combining the Gabor transform (GT) and Wigner-Ville distribution (WVD). GT and WVD have been used separately on synthetic and recorded earthquake data to identify frequency shifting due to earthquake damages, but GT is prone to windowing effect and WVD involves ambiguity function. Hence to obtain better clarity and to remove the cross terms (frequency interference), GT and WVD are judiciously combined and the resultant GWT used to identify frequency shifting. Synthetic seismic response of an instrumented building and real-time earthquake data recorded on the building were investigated using GWT. It is found that GWT offers good accuracy for even slow variations in frequency, good time-frequency resolution, and localized response. Presented results confirm the efficacy of GWT when compared with GT and WVD used separately. Simulation results were quantified by the Renyi entropy measures and GWT shown to be an adequate technique in identifying localized response for structural damage detection.

关键词： time-frequency distribution seismic signals cross-term interference Gabor transform Wigner- Ville distribution Gabor-Wigner transform

Dye reduction-based electron-transfer activity monitoring assay for assessing microbial electron transfer activity of microbial fuel cell inocula

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Journal of Environmental Sciences 2020年第10期32卷 171-177页

作者： Kartik S.Aiyer roshan Rai B.S.Vijayakumar Department of Biosciences Sri Sathya Sai Institute of Higher LearningPrasanthi NilayamPuttaparthiAndhra Pradesh-515134India

Microbial fuel cells (MFC) utilize microbes as catalysts to convert chemical energy to *** used for MFC operation must therefore contain active microbial *** dye reduction-based electron-transfer activity monitoring (DREAM) assay was employed to evaluate different inocula used in MFCs for their microbial bioelectrical *** assay utilizes the redox property of Methylene Blue to undergo color change from blue to colorless state upon microbial *** extent of Methylene Blue reduction was denoted as the DREAM assay *** assay was initially performed on a microbial culture along with the growth curve and estimation of colony forming units (CFUs).DREAM coefficient correlated to the CFU/m L obtained over time as growth *** assay was then extended to water samples (domestic sewage,lake and a man-made pond) serving as inocula in *** wastewater gave the highest DREAM coefficient (0.300±0.05),followed by pond (0.224±0.07) and lake (0.157±0.04) water *** density obtained conformed to the DREAM coefficient values,with the three samples generating power densities of 46.45±5.1,36.12±3.2 and 25.08±4.3 m W/m^2 *** have also studied the role of addition of various carbon sources and their concentrations towards improving the sensitivity of the *** DREAM assay is a rapid,easy-to-perform and cost-effective method to assess inocula for their suitability as anolytes in terms of electron transfer potential in MFCs.

关键词： Dye reduction Electron transfer Methylene Blue Microbial fuel cell Wastewater

Borehole deformation based in situ stress estimation using televiewer data

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第9期15卷 2475-2481页

作者： Hamid roshan Danqi Li Ismet Canbulat Klaus Regenauer-Lieb School of Minerals and Energy Resources Engineering University of New South WalesSydneyNSW2052Australia WA School of Mines MineralsEnergy and Chemical EngineeringCurtin UniversityPerthWA6102Australia

The knowledge of in situ stress is critical in safe and optimised extraction of minerals and energy *** situ stresses are either measured directly(***)or estimated indirectly(*** breakouts).Borehole breakout analysis for in situ stress estimation is considered a relatively simple and cost-efficient *** technique,however,poses certain limitations such as complexities with progressive formation of breakouts and it requires inputs such as rock failure parameters that are not often *** a result,significant effort has been made to develop new indirect methods for in situ stress *** deformation analysis using four-arm caliper has been recently proposed for in situ stress estimation and has shown promising *** this study,we demonstrate a new methodology that analyses the borehole televiewer data with the technique of borehole deformation analysis to estimate the in situ stresses through a field case *** advantages and challenges of using borehole televiewer data for stress estimation based on borehole deformation analysis are discussed and the best practice to obtain the reliable results is *** limitations of using fourarm caliper and borehole deformation analysis for in situ stress estimation are also discussed and it is shown how televiewer data can overcome such ***,the in situ stress results obtained from televiewer data and borehole deformation analysis are compared with independent in situ stress measurements to show the robustness and reliability of the proposed methodology.

关键词： In situ stress Borehole deformation Televiewer Elastic properties Downhole logging

Joint Time-Frequency Analysis of Seismic Signals:A Critical Review

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Structural Durability & Health Monitoring 2018年第2期12卷 65-83页

作者： roshan Kumar Wei Zhao Vikash Singh Miami College of Henan University Henan475000China Yokohama University 24000Japan

This paper presents an evaluation of time-frequency methods for the analysis of seismic *** of the present work is to describe,how the frequency content of the signal is changing in *** theoretical basis of short time Fourier transform,Gabor transform,wavelet transform,S-transform,Wigner distribution,Wigner-Ville distribution,Pseudo Wigner-Ville distribution,Smoothed Pseudo Wigner-Ville distribution,Choi-William distribution,Born-Jordan Distribution and cone shape distribution are *** strengths and weaknesses of each technique are verified by applying them to a particular synthetic seismic signal and recorded real time earthquake data.

关键词： Time-frequency distribution Seismic signals Cross-term interference Autoterm Gabor transform Wigner-Ville distribution

The role of gut microbiota in the gut-brain axis:current challenges and perspectives

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Protein & Cell 2013年第6期4卷 403-414页

作者： Xiao Chen roshan D’Souza Seong-Tshool Hong BDRD Research Institute JINIS Biopharmaceuticals Inc948-9 DunsanBongdongWanjuChonbuk 565-902South Korea Department of Microbiology and Genetics and Institute for Medical Science Chonbuk National University Medical SchoolJeonju 561-712South Korea

Brain and the gastrointestinal(GI)tract are intimately con-nected to form a bidirectional neurohumoral communica-tion *** communication between gut and brain,knows as the gut-brain axis,is so well established that the functional status of gut is always related to the condi-tion of *** researches on the gut-brain axis were traditionally focused on the psychological status affecting the function of the GI ***,recent evidences showed that gut microbiota communicates with the brain via the gut-brain axis to modulate brain development and behavioral *** recent fi ndings on the new role of gut microbiota in the gut-brain axis implicate that gut microbiota could associate with brain functions as well as neurological diseases via the gut-brain *** elucidate the role of gut microbiota in the gut-brain axis,precise identification of the composition of microbes constituting gut microbiota is an essential ***,identifi cation of microbes constituting gut microbiota has been the main technological challenge currently due to massive amount of intestinal microbes and the diffi culties in culture of gut *** methods for identifi ca-tion of microbes constituting gut microbiota are depend-ent on omics analysis methods by using advanced high tech ***,we review the association of gut microbiota with the gut-brain axis,including the pros and cons of the current high throughput methods for identi-fi cation of microbes constituting gut microbiota to eluci-date the role of gut microbiota in the gut-brain axis.

关键词： gut microbiota the gut-brain axis central nervous system high throughput methods next-generation sequencings

Watershed classification by remote sensing indices： A fuzzy c-means clustering approach

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Journal of Mountain Science 2017年第10期14卷 2053-2063页

作者： Bahram CHOUBIN Karim SOLAIMANI Mahmoud HABIBNEJAD roshan Arash MALEKIAN Department of Watershed Management Sari University of Agricultural Sciences and Natural Resources P.O. Box 737 Sari Iran Department of Reclamation of Arid and Mountainous Regions University of Tehran Karaj 31585-3314 Iran

Determining the relatively similar hydrological properties of the watersheds is very crucial in order to readily classify them for management practices such as flood and soil erosion control. This study aimed to identify homogeneous hydrological watersheds using remote sensing data in western Iran. To achieve this goal, remote sensing indices including SAVI, LAI, NDMI, NDVI and snow cover, were extracted from MODIS data over the period 2000 to 2015. Then, a fuzzy method was used to clustering the watersheds based on the extracted indices. A fuzzy c-mean(FCM) algorithm enabled to classify 38 watersheds in three homogeneous *** optimal number of clusters was determined through evaluation of partition coefficient, partition entropy function and trial and error. The results indicated three homogeneous regions identified by the fuzzy c-mean clustering and remote sensing product which are consistent with the variations of topography and climate of the study area. Inherently,the grouped watersheds have similar hydrological properties and are likely to need similar management considerations and measures.

关键词： Karkheh watershed Fuzzy c-means clustering Watershed classification Homogeneous sub-watersheds