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Two-dimensional investigation of characteristic parameters and their gradients for the self-generated electric and magnetic fields of laser-induced zirconium plasma

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Plasma Science and Technology 2024年第5期26卷 138-155页

作者： Tayyaba SAJID shazia bashir Mahreen AKRAM Maira RAZZAQ Khaliq MAHMOOD Centre for Advanced Studies in Physics Institute of PhysicsGovernment College University LahoreLahore 54000Pakistan Department of Physics Institute of PhysicsGovernment College University LahoreLahore 54000Pakistan

Two-dimensional diagnosis of laser-induced zirconium(Zr)plasma has been experimentally performed using the time-of-flight method by employing Faraday cups in addition to electric and magnetic *** characteristic parameters of laser-induced Zr plasma have been evaluated as a function of different laser irradiances ranging from 4.5 to 11.7 GW cm-2 at different axial positions of 1–4 cm with a fixed radial distance of 2 cm.A well-supporting correlation between the plume parameters and the laser-plasma-produced spontaneous electric and magnetic(E and B)fields was *** measurements of the characteristic parameters and spontaneously induced fields were observed to have an increasing trend with the increasing laser ***,when increasing the spatial distance in both the axial and radial directions,the plasma parameters(electron/ion number density,temperature and kinetic energy)did not show either continuously increasing or decreasing trends due to various kinetic and dynamic processes during the spatial evolution of the ***,the E and B fields were observed to be always diffusing away from the *** radial component of electron number densities remained higher than the axial number density component,whereas the axial ion number density at all laser irradiances and axial distances remained higher than the radial ion number *** higher axial self-generated electric field(SGEF)values than radial SGEF values are correlated with the effective charge-separation mechanism of electrons and *** generation of a self-generated magnetic field is observed dominantly in the radial direction at increasing laser irradiance as compared to the axial one due to the deflection of fast-moving electrons and the persistence of two-electron temperature on the radial axis.

关键词： Faraday cup axial and radial expansion space-charge effect laser-induced zirconium plasma two-electron temperature distribution self-generated electric and magnetic fields

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Effect of fluence and ambient environment on the surface and structural modification of femtosecond laser irradiated Ti

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Chinese Physics B 2016年第1期25卷 789-795页

作者： Umm-i-Kalsoom shazia bashir Nisar Ali M Shahid Rafique Wolfgang Husinsky Chandra S R Nathala Sergey V Makarov Narjis Begum Institute for Applied Physics Vienna University of TechnologyViennaAustria Centre for Advanced Studies in Physics GC University LahorePakistan Department of Physics The University of LahorePala'stan Department of Basic Sciences and Humanities University of Engineering and Technology FasalabadPakistan Department of Physics University of Engineering and Technology LahorePakistan P.N.Lebedev Physics Institute RAS MoscowRussia Department of Physics COMSATS Institute of Information and TechnologyIslamabadPakistan

Under certain conditions, ultrafast pulsed laser interaction with matter leads to the formation of self-organized conical as well as periodic surface structures （commonly reffered to as, laser induced periodic surface structures, LIPSS）. The purpose of the present investigations is to explore the effect of fsec laser fluence and ambient environments （Vacuum ＆ 02） on the formation of LIPSS and conical structures on the Ti surface. The surface morphology was investigated by scanning electron microscope （SEM）. The ablation threshold with single and multiple （N = 100） shots and the existence of an incubation effect was demonstrated by SEM investigations for both the vacuum and the 02 environment. The phase analysis and chemical composition of the exposed targets were performed by x-ray diffraction （XRD） and energy dispersive x-ray spectroscopy （EDS）, respectively. SEM investigations reveal the formation of LIPSS （nano ＆ micro）. FFT d-spacing calculations illustrate the dependence of periodicity on the fluence and ambient environment. The periodicity of nano-scale LIPSS is higher in the case of irradiation under vacuum conditions as compared to 02. Furthermore, the 02 environment reduces the ablation threshold. XRD data reveal that for the 02 environment, new phases （oxides of Ti） are formed. EDS analysis exhibits that after irradiation under vacuum conditions, the percentage of impurity element （A1） is reduced. The irradiation in the 02 environment results in 15% atomic diffusion of oxygen.

关键词： LIPSS ablation threshold incubation coefficient structural modification

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Femtosecond laser induced nanostructuring of zirconium in liquid confined environment

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Chinese Physics B 2017年第1期26卷 310-319页

作者： Nisar Ali shazia bashir Umm-i-Kalsoom M.Shahid Rafique Narjis Begum Wolfgang Husinsky Ali Ajami Chandra S.R.Natahala Laser Laboratories Institute for Applied Physics Vienna University of Technology 1040 Vienna Austria Department of Basic Sciences and Humanities University of Engineering and Technology Lahore Faisalabad Campus Faisalabad Pakistan Laser Laboratories Centre for Advanced Studies m Physics GC University 1-Church Road Lahore Pakistan Department of Physics GC University Kachehri Road Lahore Pakistan Department of Physics Riphah International University Islamahad (Lahore Campus) Lahore Pakistan Department of Physics University of Engineering and Technology Lahore Pakistan Department of Physics COMSATS Institute of Information Technology Islamabad Pakistan

The surface, structural, and mechanical properties of zirconium after irradiation with Ti： sapphire laser（800 nm, 30 fs,1 k Hz） have been investigated. The zirconium targets were exposed for a varying number of laser pulses ranging from 500 to 2000 at a fixed fluence of 3.6 J/cm^2 corresponding to an intensity of 1.2×10^14W/cm^2 in ambient environments of deionized water and propanol. A scanning electron microscope（SEM） was employed to investigate the surface morphology of the irradiated zirconium. The SEM analysis shows the formation of various kinds of features including nanoscale laser induced periodic surface structures（LIPSS）, sponge like surface structure, flakes, conical structures, droplets, pores, and cavities. The energy dispersive x-ray spectroscopy（EDS） analysis exhibits the variation in chemical composition along with an enhanced diffusion of oxygen under both ambient conditions. The crystal structure and phase analyses of the exposed targets were explored by x-ray diffraction（XRD） and Raman spectroscopy techniques, respectively. The XRD analysis confirms the presence of various phases of zirconium hydride and zirconia after ablation in both de-ionized water and propanol. However, excessive hydrides are formed in the case of propanol. The Raman analysis supports the EDS and XRD results. It also reveals the presence of oxides（zirconia） after irradiation in both de-ionized water and propanol *** chemical reactivity of zirconium was significantly improved in the presence of liquids which were accountable for the growth of novel phases and modification in the chemical composition of the irradiated Zr. A nanohardness tester was employed to measure the nanohardness of the laser treated targets. The initial increase and then decrease in nanohardness was observed with an increase in the number of laser pulses in the de-ionized water environment. In the case of propanol,a continuous decrease in hardness was observed.

关键词： ambient environments periodic structure crystallinity synthesis

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Laser-assisted ablation and plasma formation of titanium explored by LIBS,QCM, optical microscopy and SEM analyses along with mechanical modifications under different pressures of Ar and Ne

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Plasma Science and Technology 2023年第3期25卷 181-192页

作者： Maryam RIAZ shazia bashir Asma HAYAT Zarish NAZ Centre for Advanced Studies in Physics GC University Lahore

This study deals with the investigation of Nd:YAG laser-assisted ablation and plasma formation of Ti at irradiance of 0.85 GW cm-2 under Ar and Ne environment at various pressures ranging from 10-120 ***-induced breakdown spectroscopy is used to evaluate plasma parameters,whereas quartz crystal microbalance is used for ablation yield *** crater depth is evaluated by optical *** surface features are explored by scanning electron microscope(SEM) analysis and the micro-hardness is measured by a Vickers hardness *** is observed that the plasma parameters are higher in Ar than in Ne,and are strongly correlated with the ablation yield,ablation depth,surface features and hardness of laser-ablated *** parameters increase with increasing the pressure of environmental gases,attain their maxima at 40 Torr for Ar and at 60 Torr for ***,they show a decreasing trend up till a maximum pressure of 120 *** maximum value of the electron temperature(Te) is5480 K,number density(ne) is 1.46 × 1018 cm-3,ablation depth is 184 μm,ablation yield is3.9 × 1015 atoms/pulse and hardness is 300 HV in the case of Ar *** analysis reveals the growth of surface features,such as cones,ridges and pores,whose appearance is more distinct in Ar than Ne and is attributed to temperature,pressure and density gradients along with recoil pressure of the Ti plasma.

关键词： ablation plasma electron temperature electron density laser-induced breakdown spectroscopy surface structures

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Modification in Cu-Zn Alloy Properties by 2 MeV Ni<sup>+</sup>Ions Irradiation

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Materials Sciences and Applications 2018年第3期9卷 330-344页

作者： Shahbaz Ahmad shazia bashir Daniel Yousaf Mian Ahsan Ali Department of Physics University of Sargodha Lahore Campus Lahore Pakistan Center for Advanced Studies in Physics Government College University Lahore Pakistan

We investigate the effects of 2 MeV Ni+ ion beam irradiation with various fluence ranging from 15 × 1011 to 60 × 1014 ions/cm2 on the surface, structural and mechanical properties of Cu-Zn alloy. The modification in target properties after irradiation is confirmed by using various characterization techniques viz. SEM, XRD, UTM and Vickers micro-hardness tester. The SEM results illustrate the formation of nano sized craters with different diameters. Their average diameter decreases from 190 nm to 90 nm by increasing ion fluence. The XRD analysis of irradiated targets reveals that Ni+ ion irradiation enhances the growth of (111) phase and its peak position varies due to ion induced tensile stresses in target matrix. Tensile and Vickers micro-hardness tests verify the mechanical properties of Cu-Zn alloy reduce monotonically upon irradiation. Various mechanisms such as generation, recombination, augmentation and annihilation of ion induced defects are responsible for this reduction. Understanding the relationships between various modified properties of irradiated target is essential for growing new advanced material by irradiation.

关键词： Ion Irradiation Mechanical Properties Ion Fluence Frenkel Defects Crystallite Size

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Surface Analysis Correlated with Structural and Mechanical Properties of Laser Irradiated Brass

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Materials Sciences and Applications 2015年第1期6卷 23-32页

作者： Shahbaz Ahmad shazia bashir Daniel Yousaf Nisar Ali Tousif Hussain Center for Advanced Studies in Physics Government College University Lahore Pakistan

Brass targets were irradiated with various laser pulses of Excimer laser ranging from 1200 to 3000 for constant fluence of 3.4 J/cm2 in oxygen atmosphere (100 Torr). The surface morphology and crystallographic analyses were performed by using Scanning Electron Microscope (SEM) and X-Ray Diffractometer (XRD). SEM analysis reveals the formation of laser-induced micro-sized cavities, bumps, cones and wave-like ridges with non-uniform shape and density distribution. These features are formed for all number of pulses;however with increasing number of pulses from 1200 to 2400, the density of cavities decreases whereas, the wave-like ridges become more pronounced and bump-formation is vanished. For maximum number of 3000 shots, the appearance of cones and wave-like ridges becomes diffusive, whereas the density and size of cavities increase again. XRD analysis demonstrates that no new phases are formed in irradiated brass. However, the change in peak intensity along with lower and higher angle shifting is observed which is attributed to generation of laser induced stresses. The Yield Stress (YS), Ultimate Tensile Strength (UTS) as well as Microhardness increase monotonically with increasing number of laser pulses.

关键词： Laser Pulses Surface Morphology Mechanical Properties Crystallographic Alteration

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Energy and flux measurements of laser-induced silver plasma ions by using Faraday cup

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Plasma Science and Technology 2021年第8期23卷 188-198页

作者： Muhammad Usman Aslam BHATTI shazia bashir Asma HAYAT Khaliq MAHMOOD Rana AYUB Mubashir JAVED Muhammad Shahzad KHAN Centre for Advanced Studies in Physics(CASP) GC UniversityLahore 54000Pakistan

Silver(Ag)plasma has been generated by employing Nd:YAG laser(532 nm,6 ns)laser *** energy and flux of ions have been evaluated by using Faraday cup(FC)using time of flight(TOF)*** dual peak signals of fast and slow Ag plasma ions have been *** energy and flux of fast and slow ions tend to increase with increasing irradiance from 7 GW cm-2 to 17.9 GW cm-2 at all distances of FC from the target *** a decreasing trend of energies and flux of ions has been observed with increasing distance of FC from the *** maximum value of flux of the fast component is21.2×10^(10) cm^(-2),whereas for slow ions the maximum energy and flux values are 8.8 keV,8.2×10^(10) cm^(-2) *** the analysis of plume expansion dynamics,the angular distribution of ion flux measurement has also been *** overall analysis of both spatial and angular distributions of Ag ions revealed that the maximum flux of Ag plasma ions has been observed at an optimal angle of~15°.In order to confirm the ion acceleration by ambipolar field,the self-generated electric field(SGEF)measurements have also been performed by electric probe;these SGEF measurements tend to increase by increasing laser *** maximum value of 232 V m^(-1) has been obtained at a maximum laser irradiance of 17.9 GW cm^(-2).

关键词： laser ablation laser-induced plasma ions Faraday cup time of flight measurements self-generated electric field angular distribution

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A New Scheme of the ARA Transform for Solving Fractional-Order Waves-Like Equations Involving Variable Coefficients

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工程与科学中的计算机建模(英文) 2024年第1期138卷 761-791页

作者： Yu-Ming Chu Sobia Sultana shazia Karim Saima Rashid Mohammed Shaaf Alharthi Department of Mathematics Huzhou UniversityHuzhou313000China Department of Mathematics Imam Mohammad Ibn Saud Islamic UniversityRiyadh11461Saudi Arabia Department of Basic Sciences and Humanities UET LahoreFaisalabad Campus54800Pakistan Department of Mathematics Government College UniversityFaisalabad38000Pakistan Department of Mathematics and Statistics College of ScienceTaif UniversityP.O.Box 11099Taif21944Saudi Arabia

The goal of this research is to develop a new,simplified analytical method known as the ARA-residue power series method for obtaining exact-approximate solutions employing Caputo type fractional partial differential equations(PDEs)with variable ***-transform is a robust and highly flexible generalization that unifies several existing *** key concept behind this method is to create approximate series outcomes by implementing the ARA-transform and Taylor’s *** process of finding approximations for dynamical fractional-order PDEs is challenging,but the ARA-residual power series technique magnifies this challenge by articulating the solution in a series pattern and then determining the series coefficients by employing the residual component and the limit at infinity *** approach is effective and useful for solving a massive class of fractional-order *** appealing implementations are taken into consideration to demonstrate the effectiveness of the projected technique in creating solitary series findings for the governing equations with variable ***,several visualizations are drawn for different fractional-order *** that,the estimated findings by the proposed technique are in close agreement with the exact ***,statistical analyses further validate the efficacy,dependability and steady interconnectivity of the suggested ARA-residue power series approach.

关键词： ARA-transform Caputo fractional derivative residue-power seriesmethod analytical solutions statistical analysis

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An Improved Lung Cancer Segmentation Based on Nature-Inspired Optimization Approaches

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Computer Modeling in Engineering & Sciences 2024年第2期138卷 1051-1075页

作者： shazia Shamas Surya Narayan Panda Ishu Sharma Kalpna Guleria Aman Singh Ahmad Ali AlZubi Mallak Ahmad AlZubi Chitkara University Institute of Engineering and Technology Chitkara UniversityRajpuraPunjab140401India Higher Polytechnic School Universidad Europea del AtlánticoC/Isabel Torres 21Santander39011Spain Department of Engineering Universidad Internacional IberoamericanaAreciboPR00613USA Uttaranchal Institute of Technology Uttaranchal UniversityDehradunUttarakhand248007India Computer Science Department King Saud UniversityRiyadhSaudi Arabia Faculty of Medicine Jordan University of Science and TechnologyIrbidJordan

The distinction and precise identification of tumor nodules are crucial for timely lung cancer diagnosis andplanning intervention. This research work addresses the major issues pertaining to the field of medical imageprocessing while focusing on lung cancer Computed Tomography (CT) images. In this context, the paper proposesan improved lung cancer segmentation technique based on the strengths of nature-inspired approaches. Thebetter resolution of CT is exploited to distinguish healthy subjects from those who have lung cancer. In thisprocess, the visual challenges of the K-means are addressed with the integration of four nature-inspired swarmintelligent techniques. The techniques experimented in this paper are K-means with Artificial Bee Colony (ABC),K-means with Cuckoo Search Algorithm (CSA), K-means with Particle Swarm Optimization (PSO), and Kmeanswith Firefly Algorithm (FFA). The testing and evaluation are performed on Early Lung Cancer ActionProgram (ELCAP) database. The simulation analysis is performed using lung cancer images set against metrics:precision, sensitivity, specificity, f-measure, accuracy,Matthews Correlation Coefficient (MCC), Jaccard, and *** detailed evaluation shows that the K-means with Cuckoo Search Algorithm (CSA) significantly improved thequality of lung cancer segmentation in comparison to the other optimization approaches utilized for lung cancerimages. The results exhibit that the proposed approach (K-means with CSA) achieves precision, sensitivity, and Fmeasureof 0.942, 0.964, and 0.953, respectively, and an average accuracy of 93%. The experimental results prove thatK-meanswithABC,K-meanswith PSO,K-meanswith FFA, andK-meanswithCSAhave achieved an improvementof 10.8%, 13.38%, 13.93%, and 15.7%, respectively, for accuracy measure in comparison to K-means segmentationfor lung cancer images. Further, it is highlighted that the proposed K-means with CSA have achieved a significantimprovement in accuracy, hence can be utilized by resea

关键词： Lesion lung cancer segmentation medical imaging meta-heuristic Artificial Bee Colony(ABC) Cuckoo Search Algorithm(CSA) Particle Swarm Optimization(PSO) Firefly Algorithm(FFA) segmentation

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Is it necessary to stop glucagon-like peptide-1 receptor agonists prior to endoscopic procedure? A retrospective study

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World Journal of Gastroenterology 2024年第26期30卷 3221-3228页

作者： Haider Ghazanfar Nismat Javed Abeer Qasim Franklin Sosa Faryal Altaf shazia Khan Jaydeep Mahasamudram Abhilasha Jyala Sameer Datta Kandhi Dongmin Shin Nikhitha Mantri Haozhe Sun Siddarth Hanumanthu Harish Patel Jasbir Makker Bhavna Balar Anil Dev Sridhar Chilimuri Division of Gastroenterology Department of Internal MedicineBronxCare Health SystemIcahn School of Medicine at Mount SinaiBronxNY 10457United States Department of Internal Medicine BronxCare Health SystemIcahn School of Medicine at Mount SinaiBronxNY 10457United States

BACKGROUND Glucagon-like peptide-1 receptor agonists(GLP-1 RA)are effective in diabetes and obesity,reducing hyperglycemia by increasing insulin release and delaying gastric ***,they can cause gastroparesis,raising concerns about aspiration during *** guidelines advise discontinuing GLP-1 RA before surgery to reduce the risk of pulmonary *** To evaluate the effect of GLP-1 RAs on gastric residual contents during endosco-pic *** A retrospective chart review at BronxCare Health System,New York,from January 2019 to October 2023,assessed gastric residue and aspiration in GLP-1 RA patients undergoing endoscopic *** groups were compared based on dietary status before the *** included demographics,symptoms of gastroparesis,opiate use,hemoglobin A1c,GLP-1 agonist indication,endo-scopic details,and aspiration *** SPSS was used for analysis,cal-culating means,standard deviations,and applying Pearson’s chi-square and t-tests for associations,with P<0.05 as being *** During the study,306 patients were included,with 41.2%on a clear liquid/low residue diet and 58.8%on a regular diet before *** patients(63.1%)were male,with a mean age of 60±12 *** majority(85.6%)were on GLP-1 RAs for diabetes,and 10.1%reported digestive symptoms before *** those on a clear liquid diet,1.5%had residual food at endoscopy compared to 10%on a regular diet,which was statistically significant(P=0.03).Out of 31 patients with digestive symptoms,13%had residual food,all from the regular diet group(P=0.130).No complications were reported during or after the *** The study reflects a significant rise in GLP-1 RA use for diabetes and obesity.A 24-hour liquid diet seems safe for endoscopic procedures without *** with upper gastrointestinal symptoms might have a higher residual food risk,though not statistically *** research is needed

关键词： Glucagon-like peptide-1 agonists Gastroparesis Endoscopic procedures Residual food Complications

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