检索结果-南通市图书馆

Effect　of　Ballistic-Type　Hot　Atom　Adsorption　Mechanism　on　the　Phase　Diagram　of　Monomer　Dimer　CO-O2　Surface　Catalytic　Reaction：　A　Monte　Carlo　Simulation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2004年第6期21卷 1171-1174页

作者： M.Khalid K.M.khan A.u.Qaisrani Q.N.Malik DepartmentofPhysics GomalUniversityDeraIsmailKhanPakistan NuclearPhysicsDivision PakistanInstituteofNuclearScienceandTechnology(PINSTECH)P.O.NiloreIslamabadPakistan

We investigate the effect of the ballistic mechanism on the phase diagram using a square surface. While using this mechanism whenever an O2 molecule hits a randomly vacant selected site, the molecule breaks up into atomic form and then executes a ballistic flight. The paths of the two oxygen atoms are taken exactly to be opposite to each other, ***-parallel, and the ranges of the atoms are taken to be equal, *** may fly up to 1 or 1.414 or 2 of the atomic spacing from the site of impact. four cases have been studied on the basis of the range of hot atoms. The range of the hot oxygen atoms executing a ballistic flight might be up to the first nearest neighbourhood (1 atomic spacing from the site of impact), the second nearest neighbourhood (1.414 atomic spacing from the site of impact), the third nearest neighbourhood (2 atomic spacing from the site of impact), known as cases a, b, and c, respectively, while for case d the range of the oxygen atoms executing the ballistic flight might be up to 1 atomic spacing or 1.414 atomic spacing or 2 atomic spacing from the site of impact. The steady reactive window is observed and the continuous transition disappears. As soon as the CO partial pressure departs from zero, the production of CO2 is observed, which clearly verifies the experimental observation.

关键词： Oxygen

Optimization of gob ventilation boreholes design in longwall mining

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2020年第6期30卷 811-817页

作者： Saqib Ahmad Saki Jürgen f.Brune Muhammad usman khan university of Engineering and Technology Lahore Lahore 54890Pakistan Colorado School of Mines GoldenCO 80401USA

Gob ventilation boreholes(GVBs)are widely used for degasification in *** coal *** on geological conditions,30–50%of methane can be recovered from longwall gob using GVBs.A NIOSH funded research at the Colorado School of Mines confirmed that GVBs can efficiently reduce methane at the ***,GVBs can also draw some fresh air from the face and create explosive gas zones(EGZs).Explosive gas mixtures may be formed in gob areas due to the increased ingress of oxygen from *** is critical to identify the locations for GVBs for maximizing extraction of methane and minimizing hazards of *** study analyzes the effect of operating parameters and design of GVB on methane extraction,EGZs formation,and face and tailgate methane *** extraction,formation of EGZs,and concentration of methane in working areas are significantly impacted by various *** factors include the distance of work face and tailgate from GVBs,diameter of GVBs,vacuum pressure of wellhead,GVB distance from the roof of the coal seam,and number of operating GVBs in a *** fluid dynamics(CfD)evaluations suggest optimal design and operating parameters of GVBs that can contribute to maximum benefits with minimum risks.

关键词： Longwall mining Explosive gas zones Computational fluid dynamics Gob ventilation boreholes

Structural and dielectric properties of doped ferrite nanomaterials suitable for microwave and biomedical applications

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2015年第5期25卷 419-424页

作者： Imran Sadiq Shahzad Naseem Muhammad Naeem Ashiq M.A.khan Shanawer Niaz M.u.Rana Centre of Excellence in Solid State Physics University of the Punjab Institute of Chemical Sciences Bahauddin Zakariya University Department of Physics BUITEMS 4. Department of Physics University of Sargodha

The sol-gel auto-combustion method was adopted to synthesize nanomaterials of single-phase X-type hexagonal ferrites with the composition of Sr;Gd;Ni;fe;Cd;O;（x=0.00,0.02,0.04,0.06,0.08,0.10 and y = 0,0.1,0.2,0.3,0.4,0.5）.The structural properties were carried out by XRD analysis and the lattice parameters show variation with the doping of *** average particle size measured by TEM was in the range of 8-10 nm which is beneficial in obtaining suitable signal-to-noise ratio in recording media and biomedical *** room temperature resistivity enhanced with the increase of the dopant *** increase in resistivity indicates that the synthesized materials can be considered good for the formation of the multilayer chip inductors（MLCIs） as well as for the reduction of eddy current *** dielectric constant decreased with the increase in the frequency which is the general reported trend of the hexagonal ferrites and can be explained on the basis of Koop’s theory and Maxwell-Wagner *** abnormal dielectric behavior indicates the formation of small polarons in the *** maximum value of tangent loss at low frequencies reflects the application of these materials in medium frequency devices（Mf）.

关键词： Sol–gel Nanocrystalline materials Thermal properties Electrical properties Dielectric properties

Slip flow of MHD Casson fluid in an inclined channel with variable transport properties

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2020年第9期72卷 21-38页

作者： K V Prasad Hanumesh Vaidya C Rajashekhar Sami ullah khan G Manjunatha J u Viharika Department of Mathematics Vijayanagara Sri Krishnadevaraya UniversityVinayaka NagarBallari-583105KarnatakaIndia Bhaskaracharya Study Chair Karnataka State Akkamahadevi Women's UniversityVijayapuraKarnatakaIndia Department of Mathematics COMSTAS University IslamabadSahiwal Campus 54000Pakistan Department of Mathematics Manipal Institute of TechnologyManipal Academy of Higher EducationManipalKarnataka576104-India

Due to the instructive role of the peristaltic phenomenon in the human body, interests have been developed in recent years towards peristaltic transport with various thermo-physical *** current investigation reveals the effects of the magnetic field and variable transport properties on the peristaltic transport of a Casson fluid slip flow through an inclined *** coupled partial differential equations regulate the fluid flow. Through the perturbation method, the momentum and energy equations are solved for small values of variable viscosity and thermal conductivity, and the closed-form solution is obtained for mass transfer. The impact on physiological quantities of related parameters of interest is evaluated and discussed via graphs. The results obtained for the current flow represent some interesting behaviors which have applications in the biomedical field.

关键词： velocity slip thermal slip concentration slip variable viscosity yield stress

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

在线全文

学校读者我要写书评

暂无评论

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

Discrete time dynamics of a SIRD reinfection model

在线全文

学校读者我要写书评

暂无评论

International Journal of Biomathematics 2023年第5期16卷 49-70页

作者： f.f.Eshmatov u.u.Jamilov Kh.O.Khudoyberdiev 221 School 33Feruza Street 100124 TashkentUzbekistan V.I.Romanovskiy Institute of Mathematics uzbekistan Academy of Sciences 9 University Street100174 TashkentUzbekistan AKfA university 264National Park Street Barkamol MFYYangiabad VillageQibray District 111221 Tashkent RegionUzbekistan National university of uzbekistan 4 University Street100174 TashkentUzbekistan

This paper deals with a discrete-time dynamical system generated by a modified susceptible-infected-recovered-dead model(SIRD model;nonlinear operator)in threedimensional *** introduce a novel approach that incorporates the SIRD model with the quadratic stochastic operator(QSO)that allows for real-time *** basic reproductive number Ro is *** describe the set of fixed points of the operator and demonstrate that all fixed points are ***,we study the asymptotical behavior of the trajectories of this system and show that SIRD operators havea regularity property.

关键词： Modeling quadratic stochastic operator regular operator

Plasmid mediated multiple antibiotic resistance in Escherichia coli isolated from community acquired infection of urinary tract in Aligarh Hospital

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Medicine 2008年第2期1卷 12-15页

作者： Asad u khan Saeedut Zafar Ali Mohammed S Zaman Interdisciplinary Biotechnology unit A.M.U.Aligarh 202002India

This study was to investigate the current trends of multiple drug resistance in bacteria against antibiotics for the proper empirical *** isolates were collected from community-acquired infection of urinary tract patients in Aligarh India from March 1999 to August *** susceptibility test was performed,using the disc diffusion method followed by plasmid isolation by the method of Kado and *** experiments were performed by the method of Lederberg and *** study revealed that this infection was more common in young *** strains of *** isolated during the course of study were found to show multiple antibiotic resistance which was further characterized as plasmid-borne drug *** study shows that *** may be one of the important causative agents of urinary tract infection(uTI) in young women.

关键词： plasmid drug resistance uTI

Wavelet analysis of stagnation point flow of non-Newtonian nanofluid

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2019年第8期40卷 1211-1226页

作者： M.HAMID M.uSMAN R.u.HAQ4 Z.H.khan Wei WANG School of Mathematical Sciences Peking UniversityBeijing 100871China BIC-ESAT College of EngineeringPeking UniversityBeijing 100871China State Key Laboratory for Turbulence and Complex Systems Department of Mechanics and Engineering SciencePeking UniversityBeijing 100871China Department of Electrical Engineering Bahria UniversityIslamabad 44000Pakistan State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource & HydropowerSichuan UniversityChengdu 610065China Key Laboratory of Advanced Reactor Engineering and Safety Ministry of Education Tsinghua UniversityBeijing 100084China

The wavelet approach is introduced to study the influence of the natural convection stagnation point flow of the Williamson fluid in the presence of thermophysical and Brownian motion effects. The thermal radiation effects are considered along a permeable stretching surface. The nonlinear problem is simulated numerically by using a novel algorithm based upon the Chebyshev wavelets. It is noticed that the velocity of the Williamson fluid increases for assisting flow cases while decreases for opposing flow cases when the unsteadiness and suction parameters increase, and the magnetic effect on the velocity increases for opposing flow cases while decreases for assisting flow cases. When the thermal radiation parameter, the Dufour number, and Williamson’s fluid parameter increase, the temperature increases for both assisting and opposing flow cases. Meanwhile, the temperature decreases when the Prandtl number increases. The concentration decreases when the Soret parameter increases, while increases when the Schmidt number increases. It is perceived that the assisting force decreases more than the opposing force. The findings endorse the credibility of the proposed algorithm, and could be extended to other nonlinear problems with complex nature.

关键词： Williamson nanofluid heat and mass transfer stagnation point flow assisting and opposing flow Chebyshev wavelet method

Optimization Study of Pulsed DC Nitrogen-Hydrogen Plasma in the Presence of an Active Screen Cage

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2014年第5期16卷 460-464页

作者： A.SAEED A.W.khan f.JAN H.u.SHAH M.ABRAR M.ZAKA-uI-ISLAM M.KHALID M.ZAKAuLLAH National Centre for Physics Quaid-i-Azam University Campus Islamabad Department of Physics Gomal University Department of Physics Quaid-i-Azam University Department of Physics Hazara University Mansehra Department of Physics Faculty of ScienceUniversity of Jazan

A glow discharge plasma nitriding reactor in the presence of an active screen cage is optimized in terms of current density,filling pressure and hydrogen concentrations using optical emission spectroscopy（OES）.The samples of AISI 304 are nitrided for different treatment times under optimum *** treated samples were analyzed by X-ray diffraction（XRD） to explore the changes induced in the crystallographic *** XRD pattern confirmed the formation of iron and chromium nitrides arising from incorporation of nitrogen as an interstitial solid solution in the iron lattice.A Vickers microhardness tester was used to evaluate the surface hardness as a function of treatment time（h）.The results showed clear evidence of improved surface hardness and a substantial amount of decrease in the treatment time compared with the previous work.

关键词： optical diagnostics plasma nitriding austenitic stainless steel