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HEAT-RESISTANT,PYRIDINE-BASED POLYAMIDES CONTAINING ETHER AND ESTER UNITS WITH IMPROVED SOLUBILITY

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Chinese Journal of Polymer Science 2010年第1期28卷 29-37页

作者： hassan Ebadi Shahram Mehdipour-Ataei Islamic Azad University of Shahreza P.O.Box 81145-311 ShahrezaIsfahanIran Iran Polymer and Petrochemical Institute P.O.Box 14965/115 TehranIran

A diamine containing ether and ester units, as basic monomer for the preparation of polyamides, was prepared via three consecutive reactions. Nucleophilic substitution reaction of 1,4-dihydroxy benzene with 4-nitrobenzoyl chloride produced 4-hydroxyphenyl 4-nitrobenzoate （HPNB）. Reduction of nitro groups to amino groups using Fe and HC1 resulted in preparation of 4-hydroxyphenyl 4-aminobenzoate （HPAB）. The diamine was synthesized through nucleophilic substitution reaction of HPAB with 2,6-dichloropyridine. The precursors and diamine were fully characterized by common methods, and the diamine was polycondensed with different diacid chlorides in the presence of an acid scavenger to prepare new polyamides. The polyamides were characterized, and their physical properties including thermal stability and behavior, inherent viscosity and solubility were studied.

关键词： Polyamide Polycondensation Diamine Ester Ether.

Nonsingular terminal sliding mode approach applied to synchronize chaotic systems with unknown parameters and nonlinear inputs

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Chinese Physics B 2012年第6期21卷 107-116页

作者： Mohammad Pourmahmood Aghababa hassan Feizi Electrical Engineering Department Urmia University of TechnologyUrmiaIran Department of Mathematics Mamaghan BranchIslamic Azad UniversityMamaghanIran

This paper deals with the design of a novel nonsingular terminal sliding mode controller for finite-time synchro-nization of two different chaotic systems with fully unknown parameters and nonlinear inputs. We propose a novel nonsingular terminal sliding surface and prove its finite-time convergence to zero. We assume that both the master＇s and the slave＇s system parameters are unknown in advance. Proper adaptation laws are derived to tackle the unknown parameters. An adaptive sliding mode control law is designed to ensure the existence of the sliding mode in finite time. We prove that both reaching and sliding mode phases are stable in finite time. An estimation of convergence time is given. Two illustrative examples show the effectiveness and usefulness of the proposed technique. It is worthwhile noticing that the introduced nonsingular terminal sliding mode can be applied to a wide variety of nonlinear control problems.

关键词： nonsingular terminal sliding mode finite-time synchronization uncertain parameter,nonlinear input

Mass and performance optimization of an airplane wing leading edge structure against bird strike using Taguchi-based grey relational analysis

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Chinese Journal of Aeronautics 2016年第4期29卷 934-944页

作者： hassan Pahange Mohammad Hossein Abolbashari Department of Mechanical Engineering Ferdowsi University of Mashhad Department of Mechanical Engineering Lean Production Engineering Research Center Ferdowsi University of Mashhad

Collisions between birds and aircraft are one of the most dangerous threats to flight safety. In this study, smoothed particles hydrodynamics(SPH) method is used for simulating the bird strike to an airplane wing leading edge structure. In order to verify the model, first, experiment of bird strike to a flat aluminum plate is simulated, and then bird impact on an airplane wing leading edge structure is investigated. After that, considering dimensions of wing internal structural components like ribs, skin and spar as design variables, we try to minimize structural mass and wing skin deformation simultaneously. To do this, bird strike simulations to 18 different wing structures are made based on Taguchi’s L18 factorial design of experiment. Then grey relational analysis is used to minimize structural mass and wing skin deformation due to the bird strike. The analysis of variance(ANOVA) is also applied and it is concluded that the most significant parameter for the performance of wing structure against impact is the skin thickness. Finally, a validation simulation is conducted under the optimal condition to show the improvement of performance of the wing structure.

关键词： Bird strike Grey relational analysis Multi-objective optimization Smooth particle hydrody namics(SPH) Wing leading edge structure

InGaN/GaN laser diode characterization and quantum well number effect

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Chinese Optics Letters 2009年第3期7卷 226-230页

作者： S.M.Thahab H.Abu hassan Z.hassan Nano-Optoelectronics Research and Technology Laboratory School of PhysicsUniversiti Sains Malaysia

The effect of quantum well number on the quantum efficiency and temperature characteristics of In- GaN/GaN laser diodes （LDs） is determined and investigated. The 3-nm-thick In0.13Ca0.87N wells and two 6-am-thick GaN barriers are selected as an active region for Fabry-Perot （FP） cavity waveguide edge emitting LD. The internal quantum efficiency and internal optical loss coefficient are extracted through the simulation software for single, double, and triple InGaN/GaN quantum wells. The effects of device temperature on the laser threshold current, external differential quantum efficiency （DQE）, and output wavelength are also investigated. The external quantum efficiency and characteristic temperature are improved significantly when the quantum well number is two. It is indicated that the laser structures with many quantum wells will suffer from the inhomogeneity of the carrier density within the quantum well itself which affects the LD performance.

关键词： Computer software Efficiency Fabry Perot interferometers Quantum well lasers Semiconductor lasers Semiconductor quantum wells

N^1,N^2-Bis[1-(2-hydroxyphenyl)methylidene]ethanedihydrazide as a neutral ionophore for preparation of a new Ho^(3+) PVC-membrane sensor

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Chinese Chemical Letters 2011年第6期22卷 701-704页

作者： hassan Ali Zamani Department of Applied Chemistry Quchan branch Islamic Azad University

N^1,N^2-Bis[1-（2-hydroxyphenyl）methylidene]ethanedihydrazide（MEH） was used as new compound which plays the role of an excellent ion carrier in the fabrication of a Ho（Ⅲ） membrane *** electrode shows a good selectivity for Ho（Ⅲ） ion with respect to most common cations including alkali,alkaline earth,transition and heavy metal *** electrode has a wide linear dynamic range from 1.0×10^（-6） to 1.0×10^（-2） mol/L with a Nernstian slope of 19.8±0.3 mV per decade and a low detection limit of 5.8×10^（-7） mol/L in the pH range of 2.5-9.8,while the response time was rapid（10 s）.The suggested sensor was applied to the determination of Ho（Ⅲ） ions in tap water and river water samples.

关键词： Ion-selective electrode Potentiometry Sensor PVC membrane

Fabrication of a Ho^(3+)-PVC membrane sensor based on N-phenyl-2-(thiophen-2-ylmethylene)hydrazinecarbothioamide for determination of holmium ions

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Chinese Chemical Letters 2011年第2期22卷 201-204页

作者： hassan Ali Zamani Department of Applied Chemistry Quchan BranchIslamic Azad UniversityQuchanIran

In this research,a new poly（vinyl chloride）（PVC） membrane sensor for Ho^3＋ ion based on N-phenyl-2-（thiophen-2- ylmethylene）hydrazinecarbothioamide（PHC） as an ionophore was *** sensor demonstrated good selectivity and sensitivity towards the holmium ion in comparison with variety of cations,including alkali,alkaline earth,transition and heavy metal *** effect of membrane composition and pH on the response properties of the electrode was *** detail,the suggested sensor exhibited a Nernstian behavior（with a slope of 20.4±0.3 mV decade^-1） in the range of 1.0×10^-6 to 1.0×10^-2 mol/L with a detection limit of 6.2×10^-7 mol/*** response time was relatively quick in the whole concentration range（～5 s）.The sensor usage was found to be at least 10 weeks in a pH range of *** was successfully applied in determination of fluoride ions in mouth wash preparations.

关键词： Sensor PVC membrane Ion-selective electrode Potentiometry

Erbium(Ⅲ) PVC membrane sensor based on N-(benzyloxycarbonyloxy)succinimide as a new neutral ionophore

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Chinese Chemical Letters 2011年第3期22卷 346-349页

作者： hassan Ali Zamani Department of Applied Chemistry Quchan BranchIslamic Azad UniversityQuchanIran

In this study,a new Er^3＋ sensor based on N-（benzyloxycarbonyloxy）succinimide（BCS） as a neutral carrier has been constructed. The sensor exhibits potential linear response with a Nernstian slope of 20.5±0.4 mV/decade in the concentration range of 1.0×10^-6to 1.0×10^-2mol/L of Er^3＋.It has a very short response time（10 s）,detection limit of 6.3×10^-7 mol/L and a good selectivity relative to a wide variety of other metal ions including common alkali,alkaline earth,heavy,and transition metal *** can be used in the pH range of 2.5-10.6 without any considerable divergence in *** proposed sensor was successfully applied for the recovery of Er^3＋ ions spiked in tap and river water samples.

关键词： Sensor Potentiometry Ion-selective electrode PVC membrane

Development of Machine Learning Regression Models for Predicting the Performance of Nanofibrous Scaffolds for Skin Tissue Engineering

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生物组学研究杂志(英文) 2024年第3期7卷 97-104页

作者： Salem Dina Ahmed Moharam Mohamed Hussein Hashem esraa Mamdouh Computer Engineering Department Misr University for Science and Technology (MUST University)th of October Egypt Communication Engineering Department Misr University for Science and Technology (MUST University)th of October Egypt Biomedical Engineering Department Misr University for Science and Technology (MUST University)th of October Egypt

Tissue engineering is a branch of regenerative medicine that harnesses biomaterials and stem cells to utilize the body’s natural healing responses to regenerate tissue and organs. Skin components can be rebuilt by safeguarding their structure and function with the help of advanced scaffold manufacturing techniques. It is important to combine medical concerns with the vast explosion of artificial intelligence concepts to preserve human life and improve health. Currently, machine learning can make reliable contributions to critical decision-making in a wide range of applications. Regression machine learning models rely on correlations, associations, and other relationships between a dependent variable and a group of features. The main objective of this research was to study the effects of applying machine learning techniques on the performance of nanoscaffolds. A regression tree, a random forest, AdaBoost, and a gradient boosting algorithm were applied to the dataset and clustering data. By comparing our proposed models with the relevant studies to verify each machine learning model’s optimal performance, the AdaBoost technique was shown to have the highest accuracy (98.58%, 99.6%, 98.51%, and 98.85%), with a mean absolute percentage error of 1.41% and anR2 value of 0.999, which indicates a strong correlation between the predicted and actual values for the whole dataset and all subgroups.

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Aerodynamic investigation of twist angle variation based on wing smarting for a flying wing

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Chinese Journal of Aeronautics 2021年第2期34卷 201-216页

作者： Ruhollah KARIMI KELAYEH Mohammad hassan DJAVARESHKIAN Department of Mechanical Engineering Ferdowsi University of MashhadMashhadIran

In this paper, the effects of twist angle variation on aerodynamic coefficients and flow field on the wing with wing smarting approach are studied using numerical simulation. The simulation was performed using incompressible Reynolds-Averaged Navier-Stokes(RANS) equations based on the two-equation k-x Shear Stress Transport(SST) turbulent model for flow speed30 m/s and a Reynolds number of 69000. Investigations have been carried out for several twist angles and at a specific range of angles of attack. The twist applied is the type of geometric twist(wash-out), which is linearly distributed along the span. The test case is a lambda-shaped tailless aircraft with a wing fracture on the trailing edge, and a sweep angle 56°. The results show that with increasing twist angle, the aerodynamic efficiency improves over a wide range of angles of attack,but at 0° angle of attack it will decrease significantly. By increasing the angle of attack, the effect of twist on the flow field and aerodynamic coefficients will gradually decrease;hence, at a certain amount of angle of attack, the effect of twist will stop, that angle is called the neutral brink *** stability analysis shows that by growing the twist angle, the conditions required for longitudinal stability are satisfied, and the pitch-up phenomenon will be delayed.

关键词： Aerodynamics Flying wing Twist Wing smarting Numerical simulation