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Acta Geologica Sinica(English Edition) 2023年第1期97卷 163-175页

作者： Natasha khan Awais ALI Salahudin KHUrSHEED Kashif ALI Muhammad saeed Department of Earth Sciences Abbottabad University of Science and TechnologyHavelian 22500Khyber PakhtunkhwaPakistan National Centre of Excellence in Geology University of PeshawarPeshawar 25130Pakistan

The Tortonian–Calabrian strata of Offshore Makran(Pakistan)is investigated for the purpose of reservoir *** stratigraphy and petrophysics indicate that the Neogene sediments have tight reservoir potential with porosities in the range of 3%–9%and 40%–50%water *** mineralogical cross plots indicate a mixed lithology with an abundance of dolomite and calcite,together with minor quartz content and *** seismic interpretation demonstrates medium–high amplitude reflection patterns,mud diapirs coupled with onlapping strata and the occurrence of bottom simulating reflectors(BSrs).The BSrs are characterized by diminished amplitude,low continuity and exhibiting acoustic blanking *** high formation pressure results indicate overpressure zones,suggesting the occurrence of overpressured shales in the Jal *** presence of mud diapirs and gas chimneys are the result of tectonic forces acting at the junction of the Arabian,Indian and Eurasian plates,whereas,BSrs prove the existence of gas charged sediments supporting the formation of mud diapirism in the *** is concluded that the high rates of sedimentation during the Neogene are likely to have contributed to the development of the high formation *** mud weights,casing policies,pore pressure transients and geophysical inversion studies will help alleviate drilling risks in future exploration strategies.

关键词： seismic reservoirs overpressure Neogene Makran

Carbon nanotube cuprous oxide composite based pressure sensors

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Chinese Physics B 2012年第1期21卷 329-333页

作者： Kh.S.Karimov Muhammad Tariq saeed Chani Fazal Ahmad Khalid Adam khan rahim khan GIK Institute of Engineering Sciences and Technology Topi 23640District SwabiPakistan Physical Technical Institute of Academy of Sciences Rudaki Ave.33Dushanbe 734025Tajikistan

In this paper, we present the design, the fabrication, and the experimental results of carbon nanotube （CNT） and Cu20 composite based pressure sensors. The pressed tablets of the CNT Cu20 composite are fabricated at a pressure of 353 MPa. The diameters of the multiwalled nanotubes （MWNTs） are between 10 nm and 30 nm. The sizes of the Cu20 micro particles are in the range of 3-4 μm. The average diameter and the average thickness of the pressed tablets are 10 mm and 4.0 mm, respectively. In order to make low resistance electric contacts, the two sides of the pressed tablet are covered by silver pastes. The direct current resistance of the pressure sensor decreases by 3.3 times as the pressure increases up to 37 kN/m^2. The simulation result of the resistance-pressure relationship is in good agreement with the experimental result within a variation of ±2%.

关键词： carbon nanotubes Cu20 micro-powder pressure sensor simulation

Competitive role of nitrogen functionalities of N doped GO and sensitizing effect of Bi_(2)O_(3)QDs on TiO_(2)for water remediation

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Journal of Environmental Sciences 2021年第10期33卷 107-119页

作者： Saima Noor Shamaila Sajjad Sajjad Ahmed khan Leghari Cristina Flox saeed Ahmad International Islamic University Islamabad 44000Pakistan Department of Chemistry and Materials Science Aalto UniversityEspoo 16100Fl-00076Finland Pakistan Institute of Engineering and Applied Sciences Islamabad 44000Pakistan Department of Applied Physics Aalto UniversityEspoo 15100Fl-00076Finland

The promising solar irradiated photocatalyst by pairing of bismuth oxide quantum dots(BQDs)doped TiO_(2)with nitrogen doped graphene oxide(NGO)nanocomposite(NGO/BQDs-TiO_(2))was *** was used for degradation of organic pollutants like 2,4-dichlorophenol(2,4-DCP)and stable dyes,*** B and Congo red.X-ray diffraction(XrD)profile of NGO showed reduction in oxygenic functional groups and restoring of graphitic crystal *** characteristic diffraction peaks of TiO_(2)and its composites showed crystalline anatase TiO_(2).Morphological images represent spherical shaped TiO_(2)evenly covered with BQDs spread on NGO *** surface linkages of NO-O-Ti,C-O-Ti,Bi-O-Ti and vibrational modes are observed by Fourier transform infrared spectroscopy(FTIr)and raman *** and NGO modified TiO_(2)results into red shifting in visible region as studied in diffused reflectance spectroscopy(DrS).NGO and BQDs in TiO_(2)are linked with defect centers which reduced the recombination of free charge carriers by quenching of photoluminescence(PL)intensities.X-ray photoelectron spectroscopy(XPS)shows that no peak related to C-O in NGO/BQDs-TiO_(2)is *** indicated that doping of nitrogen into GO has reduced some oxygen functional *** functionalities in NGO and photosensitizing effect of BQDs in ternary composite have improved photocatalytic activity against organic *** byproducts during photo degradation process of 2,4-DCP were studied through high performance liquid chromatography(HPLC).Study of radical scavengers indicated that O_(2)^(·-) has significant role for degradation of 2,*** investigations propose that fabricated nanohybrid architecture has potential for degradation of environmental pollutions.

关键词： Bi_(2)O_(3)quantum dots Nitrogen doped graphene oxide Nitrogen defects TiO_(2) 2,4-Dichlorophenol Water treatment

Fault-tolerant Deadbeat Model Predictive Current Control for a Five-phase PMSM with Improved SVPWM

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Chinese Journal of Electrical Engineering 2021年第3期7卷 111-123页

作者： Suleman saeed Wenxiang Zhao Huanan Wang Tao Tao Faisal khan School of Electrical and Information Engineering Jiangsu UniversityZhenjiang 212013China Department of Electrical and Computer Engineering COMSATS University IslamabadAbbottabad CampusAbbottabad 22060Pakistan

The main drawbacks of traditional finite set model predictive control are high computational load,large torque ripple,and variable switching frequency.A less complex deadbeat(DB)model predictive current control(MPCC)with improved space vector pulse-width modulation(SVPWM)under a single-phase open-circuit fault is *** proposed method predicts the reference voltage vector in the a-β subspace by employing the deadbeat control principle on the machine predictive model;thus,the exhaustive exploration procedure is avoided to relieve the computational *** perform the constant switching frequency operation and achieve better steady-state performance,a modified SVPWM strategy is developed with the same conventional structure,which modulates the reference voltage *** new approach is based on a redesigned and adjusted post-fault virtual voltage vector space distribution that eliminates the y-axis harmonic components in the x-y subspace and ensures the generation of symmetrical PWM ***,the combined merits of the DB,MPCC,and SVPWM methods are *** verify the effectiveness of the proposed control scheme,comparative experiments are performed on a five-phase permanent magnet synchronous motor(PMSM)drive system.

关键词： Five-phase fault-tolerant permanent magnet deadbeat model predictive control space vector modulation

Development and Validation of a Liquid Chromatographic Method for the Determination of Leflunomide： Application to in vitro Drug Metal Interactions

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Chinese Journal of Chemistry 2011年第9期29卷 1933-1938页

作者： Sultana, Najma Muhammad, saeed Arayne khan, Moona Mehboob Nawaz, Muhammd United Biotechnologies Karachi 75290 Pakistan Jinnah Medical and Dental College Karachi Pakistan Department of Chemistry College of Science UAE University A1-Ain P.O. Box 17551 UAE

Leflunomide is a leading drug for the treatment of rheumatoid arthritis. The principle aim of this study was to develop and validate an rP-HPLC method for the determination of leflunomide in bulk and pharmaceutical dosage form using diclofenac sodium as an internal standard. For this purpose, chromatography was accomplished on a Purospher Start, C18 （5 μm, 12.5 cm×0.46 cm） column at ambient temperature. Methanol ： water （80 ： 20, V/V） solvent system was selected as mobile phase, the pH of which was adjusted to 3.4 by ortho-phosphoric acid and de- livered at a flow rate of 1.2 mLomin-1. Seperation of leflunomide and diclofenac sodium was carried out on a Purospher Start, C18 equipped with a UV-visible detector at 248 nm. The suitability of the method for the quantita- tive determination of the drugs is proven by validation in accordance with the requirements laid down by the Inter- national Conference on Harmonization （ICH） guidelines. The method was accurate （99.55%--100.03%）, specific, linear （r2〉0.999） and precise （intra-day precision 0.023%--0.93% and inter-day precision 0.26%--0.944%） in the range of 0.5--20 μg·mL^-1. The minimum limit of detection and quantification in pharmaceutical formulation were 0.05 and 0.15 μ***^-1, respectively. Thus the proposed method is simple, accurate, reproducible and suitable for the routine analysis of leflunomide in pharmaceutical formulations and was applied to study in vitro drug-metal interactions.

关键词： leflunomide liquid chromatography analytical method in vitro interaction metal

Detecting abrupt change in land cover in the eastern Hindu Kush region using Landsat time series(1988-2020)

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Journal of Mountain Science 2022年第6期19卷 1699-1716页

作者： saeed A.khan Kim A.VANSELOW Oliver SASS Cyrus SAMIMI Department of Earth Sciences University of Bayreuth95447 BayreuthGermany Institute of Geography Friedrich-Alexander-University of Erlangen-Nürnberg91058 ErlangenGermany Bayreuth Centre of Ecology and Environmental research University of Bayreuth95448 BayreuthGermany

Land cover change in the semi-arid environment of the eastern Hindu Kush region is driven by anthropogenic activities and environmental change impacts. Natural hazards, such as floods presumably influenced by climatic change, cause abrupt change of land cover. So far, little research has been conducted to investigate the spatiotemporal aspects of this abrupt change in the valleys. In order to explore the abrupt change in land cover and floods as its possible drivers in the eastern Hindu Kush, a semi-arid mountain region characterized by complex terrain, vegetation variation, and precipitation seasonality, we analyzed long-term Landsat image time series from 1988 to 2020 using Breaks For Additive Seasonal and Trend(BFAST). Overall, BFAST effectively detected abrupt change by using Landsat-derived Modified Soil Adjusted Vegetation Index(MSAVI). The results of our study indicate that approximately 95% of the study area experienced at least one abrupt change during 1988-2020. The years 1991, 1995, 1998, 2007, and 2016 were detected as the peak years, with the peaks occurring in different seasons. The annual trend of abrupt change is decreasing for the study area. The seasonality of abrupt change at the catchment level shows an increasing trend in the spring season for the southern catchments of Panjkora and Swat. The spatial distribution patterns show that abrupt change is primarily concentrated in the floodplains indicating that flooding is the primary driver of the land cover change in the region. We also demonstrated the accurate detection of past flood events(2015) based on the two case examples of Ayun, rumbur, and Kalash valleys. The detection of the flood events was verified by fieldwork and historical high-resolution Google Earth imagery. Finally, our study provides an example of applying Landsat time series in a dry mountain region to detect abrupt changes in land cover and analyze impact of natural hazards such as floods.

关键词： Land cover change Floods Natural hazards BFAST Chitral Pakistan

General Solution for Unsteady Natural Convection Flow with Heat and Mass in the Presence of Wall Slip and ramped Wall Temperature

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Communications in Theoretical Physics 2019年第6期71卷 647-657页

作者： saeed Ullah Jan Sami Ul Haq Syed Inayat Ali Shah Ilyas khan Muhammad Atif khan Faculty of Mathematics and Statistics Ton Duc Thang UniversityHo Chi Minh CityVietnam Department of Mathematics Islamia College UniversityPeshawar25000Pakistan Department of Mathematics Kohat University of Science&TechnologyKohat26000Pakistan

This work is focused on the effect of heat and mass transfer with unsteady natural convection flow of viscous fluid along with ramped wall temperature under the assumption of the slip wall condition at the boundary. Analytical solutions are obtained by using Laplace transformation to the non-dimensional set of governing equations containing velocity, temperature and concentration. Moreover, the expression for skin-friction is derived by differentiating the analytical solutions of fluid velocity. Numerical tables for Skin-friction, Sherwood number and Nusselt-number are examined. For the physical aspects of the flow, we use various values of involved physical parameters such as Prandtl number(Pr), slip parameter(η), Schmidt number(Sc), buoyancy ratio parameter(N), Sherwood number(Sh), and time(t). Additionally, the general solutions are plotted graphically and a comprehensive theoretical section of numerical discussions is included.

关键词： slip boundary condition heat and mass transfer skin-friction

Energy-Efficient Scheduling for a Cognitive IoT-Based Early Warning System

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Computers, Materials & Continua 2022年第6期71卷 5061-5082页

作者： saeed Ahmed Noor Gul Jahangir.khan Junsu Kim Su Min Kim Department of Electronics Engineering Korea Polytechnic UniversitySiheung15073Korea Mirpur University of Science and Technology Mirpur10250Pakistan Department of Electronics University of PeshawarPeshawar25120Pakistan Sarhad University of Science and Information Technology Peshawar25000Pakistan

Flash floods are deemed the most fatal and disastrous natural hazards globally due to their prompt onset that requires a short prime time for emergency *** Internet of things(CIoT)technologies including inherent characteristics of cognitive radio(Cr)are potential candidates to develop a monitoring and early warning system(MEWS)that helps in efficiently utilizing the short response time to save lives during flash ***,most CIoT devices are battery-limited and thus,it reduces the lifetime of the *** tackle these problems,we propose a CIoTbased MEWS to slash the fatalities of flash *** extend the lifetime of the MEWS by conserving the limited battery energy of CIoT sensors,we formulate a resource assignment problem for maximizing energy *** solve the problem,at first,we devise a polynomial-time heuristic energyefficient scheduler(EES-1).However,its performance can be unsatisfactory since it requires an exhaustive search to find local optimum values without consideration of the overall network energy *** enhance the energy efficiency of the proposed EES-1 scheme,we additionally formulate an optimization problem based on a maximum weight matching bipartite ***,we additionally propose a Hungarian algorithm-based energy-efficient scheduler(EES-2),solvable in polynomial *** simulation results show that the proposed EES-2 scheme achieves considerably high energy efficiency in the CIoT-based MEWS,leading to the extended lifetime of the MEWS without loss of throughput performance.

关键词： Flash floods internet of things cognitive radio early warning system network lifetime energy efficiency

Behavioral effects of a four-wing attractor with circuit realization: a cryptographic perspective on immersion

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Communications in Theoretical Physics 2020年第12期72卷 35-70页

作者： Najeeb Alam khan Muhammad Ali Qureshi Tooba Hameed saeed Akbar Saif Ullah Department of Mathematics University of KarachiKarachi 75270Pakistan Department of Physics University of KarachiKarachi 75270Pakistan Department of Mathematics Government College UniversityLahore 54000Pakistan

In this paper,we propose an innovative chaotic system,combining fractional derivative and sinehyperbolic nonlinearity with circuit *** study of this system is conducted via an analog circuit simulator,using two anti-parallel semiconductor diodes to provide hyperbolic sine nonlinearity,and to function as operational *** multi-stability of the system is also enhanced with the help of multi-equilibrium points for distinct real orders of *** system explores the generation of a four-wing attractor in different phases,both numerically and *** changing the input parameters of the system,different graphs are generated for current flow in state,phase,and space,to confirm the precision of the fractional order derivatives.A reasonable simulation shows that the deliberate circuit provides effective chaos in terms of speed and accuracy,which is comensurate with the numerical *** nonlinear chaotic behavior is utilized to encrypt sound(.wav),images(.jpg),and animated(.gif)data which are a major requirement for the security of communication *** proposed circuit performs chaos and cryptographic tasks with high-effective analog computation,and constitutes a novel approach to this area of research.

关键词： multi-wing attractors hyperbolic sine circuit realization encryption

Evolution of heart transplant donor characteristics in the 21st century: A United States single center’s experience

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World Journal of Transplantation 2024年第3期14卷 22-29页

作者： Alexander M Spring Christiana Gjelaj Shivank Madan Snehal r Patel Omar saeed Sandhya Murthy Yogita rochlani Daniel B Sims Sasha Vukelic Stephen J Forest Jamil F Borgi Daniel J Goldstein Ulrich P Jorde Montefiore-Einstein Center for Heart and Vascular Care Montefiore Medical CenterAlbert Einstein College of MedicineBronxNY 10467United States Division of Cardiothoracic Surgery Tulane UniversityNew OrleansLA 70112United States

Despite a record setting number of heart transplants performed annually,the national donor shortage continues to plague transplant teams across the United *** we describe the barriers to adaptation of numerous“non-traditional”orthotopic heart transplant donor characteristics including donors with hepatitis C virus,those meeting criteria for donation after cardiac death,donors with coronavirus disease 19 infection,donors with the human immunodeficiency virus,and grafts with left ventricular systolic *** center’s objective was to increase our transplant volume by expanding our donor pool from“traditional”donors to these“non-traditional”*** detail how medical advances such as certain laboratory studies,pharmacologic interventions,and organ care systems have allowed our center to expand the donor pool thereby increasing transplantation volume without adverse effects on outcomes.

关键词： Orthotopic heart transplantation Hepatitis C virus COVID-19 Left ventricular systolic dysfunction Human immunodeficiency virus Donation after cardiac death