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Evolution of plasma parameters in an Ar-n2/He inductive plasma source with magnetic pole enhancement

Plasma Science and Technology 2017年第2期19卷 34-42页

作者： Maria YOunuS n u rehman M SHAFIQ M nAEEM M ZAKA-uL-ISLAM M ZAKAuLLAH Department of Physics Plasma Physics LaboratoryQuaid-i-Azam University45320 IslamabadPakistan Plasma Physics Laboratory Department of PhysicsCOMSATS Institute of Information Technology44000 IslamabadPakistan Department of Physics Faculty of ScienceJazan University114 JazanSaudi Arabia

Magnetic pole enhanced inductively coupled plasmas （MaPE-ICPs） are a promising source for plasma-based etching and have a wide range of material processing applications. In the present study Langmuir probe and optical emission spectroscopy were used to monitor the evolution of plasma parameters in a MaPE-ICP Ar-na/He mixture plasma. Electron density （ne） and temperature （Te）, excitation temperature （Texc）, plasma potential （Vp）, skin depth （6） and the evolution of the electron energy probability function （EEPF） are reported as a function of radiofrequency （RF） power, pressure and argon concentration in the mixture. It is observed that ne increases while Te decreases with increase in RF power and argon concentration in the mixture. The emission intensity of the argon line at 750.4 nm is also used to monitor the variation of the ‘high-energy tail＇ of the EEPF with RF power and gas pressure. The EEPF has a ‘bi-Maxwellian＇ distribution at low RF powers and higher pressure in a pure n2 discharge. However, it evolves into a ‘Maxwellian＇ distribution at RF powers greater than 70 W for pure n2, and at 50 W for higher argon concentrations in the mixture. The effect of argon concentration on the temperatures of two electron groups in the ‘bi-Maxwellian＇ EEPF is examined. The temperature of the low-energy electron group TL shows a decreasing trend with argon addition until the ‘thermalization＇ of the two temperatures occurs, while the temperature of high-energy electrons Ta decreases continuously.

关键词： MaPE-ICP Langmuir probe OES EEPF

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Trace-Rare-Gas Optical Emission Spectroscopy of nitrogen Plasma Generated at a Frequency of 13.56 MHz

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Plasma Science and Technology 2011年第2期13卷 208-212页

作者： n.u.rehman F.u.KHAn S.nASEER G.MuRTAZA S.S.HuSSAIn I.AHMAD M.ZAKAuLLAH Department of Physics COMSATS Institute of Information Technology Department of Physics Gomal University Department of Physics Peshawar University Department of Physics Quaid-i-Azam University

Optical emission spectroscopic measurement of trace rare gas is carried out to determine the density of nitrogen （n） atom, in a nitrogen plasma, as a function of filling pressure and RF power applied. 2% of argon, used as an actinometer, is mixed with nitrogen. In order to normalize the changes in the excitation cross section and electron energy distribution function at different operational conditions, the Ar-I emission line at 419.83 nm is used, which is of nearly the same excitation efficiency coefficient as that of the nitrogen emission line at 493.51 nm. It is observed that the emission intensity of the selected argon and atomic nitrogen lines increases with both pressure and RF power, as does the nitrogen atomic density.

关键词： optical actinometry n atomic density EEDF RF plasma

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Parametric Regression Approach for Gompertz Survival Times with Competing Risks

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Communications on Applied Mathematics and Computation 2022年第4期4卷 1175-1190页

作者： H.rehman n.Chandra Department of Statistics Ramanujan School of Mathematical SciencesPondicherry UniversityPuducherry 605014India

Regression models play a vital role in the study of data regarding survival of *** Cox proportional hazards model for regression analysis has been frequently used in sur-vival *** survival studies,it is also possible that survival time may occur with multiple occurrences of event or competing *** situation of competing risks arises when there are more than one mutually exclusive causes of death(or failure)for the person(or subject).In this paper,we developed a parametric regression model using Gompertz distribution via the Cox proportional hazards model with competing *** discussed point and interval estimation of unknown parameters and cumulative cause-specific hazard function with maximum-likelihood method and Bayesian method of *** Bayes estimates are obtained based on non-informative priors and symmetric as well as asym-metric loss *** observe the finite sample behaviour of the proposed model under both estimation procedures,we carried out a Monte Carlo simulation *** demon-strate our methodology,we also included real data analysis.

关键词： Competing risks Regression model Cause-specific hazard Gompertz distribution Parametric model Bayesian estimation MCMC algorithm

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Diurnal changes in bacterial communities in oxic surface and hypoxic middle seawater layers of the Changjiang River Estuary

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Acta Oceanologica Sinica 2021年第4期40卷 92-106页

作者： Yan Huang Lei Yuan Yingping Fan Habib u rehman Jakhrani Jianxin Wang Marine Microorganism Ecological&Application Laboratory Zhejiang Ocean UniversityZhoushan 316022China

The Changjiang River Estuary(CRE)in the East China Sea suffers from seasonal hypoxia in *** vertical distributions and seasonal changes of microbial communities in the CRE were well ***,little is known about the diurnal changes of bacterial communities in the hypoxic zone of the ***,16 S rRnA gene analysis was used to explore the changes of bacterial communities in the oxic surface and hypoxic middle seawater layers during 24 h in the *** differences between the hypoxic and oxic layers were observed:the phyla Cyanobacteria,Bacteroidetes and Acidimicrobiia were enriched in the oxic layer,whereas the phylum SAR406 and the class Deltaproteobacteria were more abundant in the hypoxic *** addition,some subtle diurnal variations of the bacterial relative abundance were found in both two *** relative abundance of Synechococcus increased at night,and this change was more obvious in the hypoxic *** similar trend was also found in some phototrophic and several heterotrophic bacteria,such as Rhodobacteraceae,OM60 and *** relative abundances peaked at 16:00 in the oxic layer,while the relative abundances peaked at around 7:00 and decreased until 13:00 in the hypoxic ***,the results of the present study suggest that some photosynthetic bacteria and several heterotrophic bacteria have similar diurnal variations implying the light and physicochemical heterogeneity in the course of a day are important for bacterial diurnal changes in the CRE.

关键词： bacterial communities diurnal changes hypoxic zone the Changjiang River Estuary

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Structural and Electronic Properties of Lutetium Doped Germanium Clusters LuGen^((+/0/-))(n=6~19):A Density Functional Theory Investigation

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Chinese Journal of Structural Chemistry 2022年第3期41卷 155-165,I0011页

作者： YAnG Zhao-Feng CAO Zhen-Zhu Aziz u rehman YAnG Ju-Cai School of Chemical Engineering Inner Mongolia University of Technologyand Inner Mongolia Key Laboratory of Theoretical and Computational Chemistry SimulationHohhot 010051China School of Energy and Power Engineering Inner Mongolia University of TechnologyHohhot 010051China

Structural growth mechanism,energetics,and electronic properties of cationic,neutral,and anionic lutetium doped germanium cluster LuGen^((+/0/-))(n=6~19)were comprehensively studied by the ABCluster unbiased global search technique with a hybrid density functional theory *** to the experimental PES,the anion evolution of structure can be clearly defined as four-phase:from the adsorbed to the link structure,then to the half cage motif,and finally to the endohedral *** results revealed that the LuGe16-as Frank-Kasper structure with high symmetry of Td can greatly enhance the *** structures have shown thermodynamic stability and appropriate energy *** materials are suitable *** approaches,including quasi-spherical geometry with closed-shell model,aromaticity,uV-Vis spectra,density of states(DOS)and partial density of states(PDOS)were applied to further support the results.

关键词： lutetium doped germanium clusters the ground state structure density functional theory electronic property

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Trace element geochemistry and stable isotopic(δ^(13)C andδ^(15)n)records of the Paleocene coals,Salt Range,Punjab,Pakistan

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International Journal of Mining Science and Technology 2022年第3期32卷 551-561页

作者： noshin Masood Tehseen Zafar Karen A.Hudson-Edwards Hafiz u.rehman Abida Farooqi Environmental Geochemistry Laboratory Department of Environmental SciencesFaculty of Biological SciencesQuaid-i-Azam UniversityPO 45320Pakistan Institute of Geochemistry Chinese Academy of SciencesGuiyang 550081China Institute of Geology University of the PunjabLahore 54590Pakistan Environment&Sustainability Institute and Camborne School of Mines University of ExeterTR109EZUK Graduate School of Sciences and Engineering Kagoshima UniversityKagoshima 890-0065Japan

The Paleocene coals of the Salt Range in the Punjab Province of Pakistan have great economic potential;however,their trace element and stable isotopic characteristics have not been studied in detail except for a few sporadic *** this study,a total of 59 coal samples of which 14 are obtained from open cast mines have been investigated for elemental composition andδ^(13)C-δ^(15)n isotopic *** contents of trace elements such as Co,Cr,Cu,Pb,Sr,Th,u,V,and Zn are 7.4,41.7,11.2,12.5,90.2,4.0,1.9,128,and 31.1 mg/kg,*** values,when compared with the World Coal Clarke values,were relatively higher in low-rank coals in comparison with Clarke values for brown ***,As(20.4 mg/kg),Co(6.6 mg/kg),Cr(22.4 mg/kg),Cu(^(13).3 mg/kg),Pb(19.2 mg/kg),Sr(^(15)4.7 mg/kg),Th(2.5 mg/kg),V(47.8 mg/kg),and Zn(75.1 mg/kg)were significantly higher in the sub-bituminous to bituminous coals of the Salt *** analysis,based on X-ray diffraction and energy dispersive X-ray spectroscopy,revealed that the studied samples contain illite,kaolinite calcite,gypsum,pyrite,and *** affinity with organic and inorganic phases of coals calculated by an indirect statistical approach indicated a positive association of ash content with Ag,Al,Co,Cr,Cs,Cu,Mn,P,Rb,Pb,Th,u,and V,suggesting the presence of inorganic components in studied ***,As,Fe,Sr,and Zn exhibit negative correlations that imply their association with the organic ***δ^(13)C andδ^(15)n isotopic range and average−24.94‰to−25.86‰(−25.41‰)and−2.77‰to 3.22‰(0.96‰),respectively,reflecting 3C type modern terrestrial vegetation were common in the palaeomires of studied coal *** addition,the trivial variations of 0.92‰and 0.45‰among^(13)C and^(15)n values can be attributed to water level fluctuations and plant assemblies.

关键词： Coal Salt Range Pakistan Geochemistry Trace elements δ^(13)C andδ^(15)n isotopes

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non Planar Electrostatic Solitary Wave Structures in negative Ion Degenerate Plasma

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Chinese Physics Letters 2011年第4期28卷 148-151页

作者： S.Hussain n.Akhtar Saeed-ur-rehman Theoretical Plasma Physics Division PINSTECHNiloreIslamabad Department of Physics and Applied Mathematics PIEAS NiloreIslamabad

Theoretical and numerical studies are performed for quantum ion acoustic solitons in planar and non-planar geometries in an unmagnetized homogenous plasma consisting of warm positive and negative ions with nonthermal electrons.A deformed Korteweg de Vries(DKdV)equation is derived by using the reductive perturbation *** numerical solution to the DKdV equation indicates that the quantum parameter,temperatures of positive ions,temperture of negative ions and electron density blatantly influence the propagation speed and the structure of quantum ion acoustic *** geometrical effects on the structure of quantum ion acoustic wave are *** is shown that the amplitude and propagation speed in spherical geometry is larger as compared to cylinderical and planar geometries for different values of the above-mentioned parameters.

关键词： method quantum planar

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The effect of positive/negative ion on the dust grain charging process in a Vasyliunas-Cairns (VC)-distributed dusty plasma system

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Plasma Science and Technology 2019年第6期21卷 58-62页

作者： n AHMAD A A ABID Y AL-HADEETHI M n S QuRESHI Saqib rehman Department of Engineering and Applied Physics University of Science and Technology of China Hefei 230026 People's Republic of China CAS Key Laboratory of Geospace Environment Department of Geophysics and Planetary ScienceUniversity of Science and Technology of China Hefei 230026 People's Republic of China Department of Physics Faculty of Sciences King Abdulaziz Unniversity Jeddah 21589 Saudi Arabia Department of Physics GC University Lahore 54000 Pakistan Department of Chemical Physics University of Science and Technology of China Hefei 230026People's Republic of China

Charging mechanism of dust particles has been considered as a growing research area in dusty plasma physics because of its exciting *** this paper,we consider a low-temperature non-equilibrium multispecies plasma model,which consists of Vasyliunas-Caims (VC) distributed electrons,negative/positive streaming ions,and negatively-charged dust grains to explain the charging mechanism of dust *** main theme of this work is to derive expressions of currents for negatively-charged dust grains (considering an equilibrium state position) in the plasma environment comprised of electrons and positive/negative streaming ions using the VC distribution *** proposed model shows that the dust grain surface potential is significantly affected by different plasma parameters such as the negative ion streaming velocity (Sn),positive ion streaming velocity (Si),spectral indices of VC distribution,negative ion charging state (Zn),positive ion charging state (Zi),and negative ion number density (ρ).

关键词： dust grain surface potential vasyliunas-cairns power law velocity distribution function multi species plasma

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Synergy and translation of allogenic bone marrow stem cells after photodynamic treatment of rheumatoid arthritis with tetra sulfonatophenyl porphyrin and TiO2 nanowhiskers

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nano Research 2016年第11期9卷 3305-3321页

作者： Fawad u. rehman Chunqiu Zhao Changyu Wu Xiaoqi Li Hui Jiang Matthias Selke Xuemei Wang State Key Laboratory of Bioelectronics School of Biological Science and Medical Engineering Southeast University Nanjing 210096 China Department of Chemistry and Biochemistry California State University Los Angeles CA 90032 USA nanjing Foreign Language School Nanjing 210096 China

Rheumatoid arthritis （RA） etiology and amelioration remains a challenge in modern therapeutics. Herein, we explored the synergistic effect of allogenic bone marrow stem cell （BMSC） translation and photodynamic treatment of RA with tetra sulfonatophenyl porphyrin （TSPP） and TiO2 nanocomposites as a new strategy for RA theranostics. The translation of BMSCs with miRnAs into infected joints in long bones post-photodynamic therapy is helpful for treating and understanding RA pathophysiology. We observed that allogenic BMSC translation combined with TSPP-TiO2 nanocomposites can significantly （p 〈 0.01） lower the concentrations of serum biomarkers （tumor necrosis factor-α and interleukin-17） in a collagen induced arthritis （CIA） murine model, both in vitro and in vivo, as well as improve other parameters such as arthritis score, BMSC count, complete blood count, and numbers of platelets, red blood cells, and white blood cells. Moreover, a fluorescent TSPP in the feet or long bones and X-ray bioimaging of RA joints revealed the clinical efficacy of BMSCs combined with TSPP-TiO2 nanocomposites. Microarray data analysis illustrated that rnomir-375-3p and rno-mir-196b-3p were up-regulated by approximately 100-fold in the BMSCs of ameliorated RA post-photodynamic therapy with TSPP-TiO2 nanocomposites. Our study not only suggests a new approach for RA theranostics, but also helps in understanding RA pathophysiology.

关键词： rheumatoid arthritis allogenic bone marrowstem cells (BMSCs) tetra sulfonatophenyl porphyrin (TSPP)-TiO2nanocomposites photodynamic treatment miRnAs

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Radioactive contents and background doses from northern alluvial sediment plains between rivers Ravi and Chenab,Pakistan

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nuclear Science and Techniques 2016年第4期27卷 127-134页

作者： Abdul Jabbar Khalid Khan Tania Jabbar Muhammad Rafique S.u.rehman Waheed Arshed Muhammad Dilband Health Physics Division Pakistan Institute of Nuclear Science and Technology (PINSTECH) Department of Physics University of Azad Jammu and Kashmir Muzaffarbad Department of Medical Physics Nuclear Medicine Oncology and Radiotherapy Institute (NORI)

Radiometric analysis of soil samples, collected from northern alluvial sediment plains between rivers Ravi and Chenab, has been carried out. Activity concentrations of^(226) Ra,^(232)Th,^(40) K and the artificial radionuclide^(137) Cs were estimated by using high-purity germanium detector. Subsequent values of activity concentrations were used to find terrestrial absorbed dose rate and annual effective doses received by resident of area. The mean radioactivity levels of^(226) Ra,^(232)Th,^(40) K and^(137)Cs were found to be 45.0 ± 1.3,59.6 ± 2.8, 613.8 ± 20.0 and 4.0 ± 0.2 Bq kg^(-1), respectively. Terrestrial absorbed dose rate and annual effective dose received by public were found to be 85.1 n Gy h^(-1)and0.5 m Sv, respectively. The activity concentrations of^(226) Ra,^(232)Th,^(40) K and^(137)Cs and resulting doses obtained for the current study were compared with data available in the literature and with international standards.

关键词：年有效剂量冲积平原平原河流放射性含量巴基斯坦泥沙 137Cs 226Ra

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