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91.
Properties of β-connected spaces 总被引:1,自引:0,他引:1
Many characterizations of semipreconnected (=β-connected) spaces are obtained by Aho and Nieminen [2]. In this paper, we obtain
further characterizations of semipreconnected spaces. We introduce β-separated and βs-connected sets and by using these sets we obtain several properties of β-connected subspaces.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
92.
Mandana Samari Kermani Ned Djilali Saeed Jafari Ebrahim Jahanshahi Javaran 《Journal of Dispersion Science and Technology》2018,39(6):777-791
The dynamics and rheology of particles in a Newtonian fluid subjected to shear are simulated using Lattice Boltzmann Method. A computationally-efficient Smoothed Profile Method is used to resolve fluid-solid interactions, and the Lennard-Jones inter-particle potential is implemented to account for inter-particle forces. The use of a bi-periodic computational domain with Lees-Edward boundary conditions allows simulation for systems consisting of a large number of particles under shear. The method is validated for single and dual particle problems and an analysis is performed for multi-particle problems under a range of shear rates and particle fractions. The introduction of particle-particle interactions, which are physically important in many engineering processes, is found to have a considerable impact on the dynamics, agglomeration and rheology. The total stress exhibits high unsteadiness primarily due to the solid component contribution, at higher particle fractions. The simulations underscore the complex interplay between shear, interparticle forces and agglomeration and the complex dependencies of the rheological properties. 相似文献
93.
A fast and accurate analytical method, which uses commercially available adsorbents (Tenax TA, Carbotrap B and C, and Carbosieve S-III), was developed for the sampling and determination of aromatic hydrocarbons, chloroaromatic compounds, and 2,3,7,8-tetrachlorodibenzo-p-dioxin. The breakthrough volume data show that Carbotrap C has a good capacity for compounds of high molecular weight, whereas Carbosieve S-III and Tenax TA are efficient for volatile compounds. The organic components are thermally desorbed and transferred to a gas chromatograph/mass spectrometer. Importantly, thermal desorption avoids conventional solvent extraction procedures and also allows reuse of adsorbent tubes. Preliminary results for recovery of analytes from tubes packed with single adsorbent prove that a single-adsorbent bed is not capable of sampling a wide range of compounds. The best method to obtain the desired collection and desorption properties is to use adsorbent tubes containing several different materials. The results of optimization studies are summarized. 相似文献
94.
The interaction of Fenitrothion with DNA has been studied using the voltammetric and spectroscopic methods. An irreversible reduction was concluded from the CV data of Fenitrothion. The values of (αn)f=1.91 and (αn)b=2.06 were measured and the reduction process of Fenitrothion was performed with 4 electrons. By using non‐linear regression analysis of CV data, the binding constant, binding site size, and diffusion coefficient for free Fenitrothion (Df) and DNA‐Fenitrothion (Db) were calculated as: 1.03×104, 1.204, 5.2×10?4 and 1.72×10?5, respectively. Also the voltammetric, spectroscopic, thermodynamic and activation energy of DNA‐Fenitrothion complex revealed that the mode of interaction might be partial‐intercalative and complex formation is entropy favored. 相似文献
95.
Sohrab Behnia Amin Jafari Farzan Ghalichi Ashkan Bonabi 《Central European Journal of Physics》2008,6(2):211-222
In this paper, the finite-element method (FEM) simulation of ultrasound brain surgery is presented. The overheating problem
of the post-target bone, which is one of the limiting factors for a successful ultrasound brain surgery, is considered. In
order to decrease bone heating, precise choices of frequency, focal pressure, and scanning path are needed. The effect of
variations in the mentioned scanning parameters is studied by means of the FEM. The resulting pressure and temperature distributions
of a transdural ultrasound brain surgery are simulated by employing the FEM for solving the Helmholtz and bioheat equations
in the context of a two-dimensional MRI-based brain model. Our results show that for a suitable value of the frequency, an
increase in focal pressure leads to a decrease in the required duration of the treatment and is associated with less heating
of the surrounding normal tissue. In addition, it is shown that at a threshold focal pressure, the target temperature reaches
toxic levels whereas the temperature rise in the bone is minimal. Wave reflections from sinus cavities, which result in constructive
interference with the incoming waves, are one of the reasons for overheating of the bone and can be avoided by choosing a
suitable scanning path.
相似文献
96.
Mohammad Saraji Narges Mehrafza Ali Akbar Hajialiakbari Bidgoli Mohammad Taghi Jafari 《Journal of separation science》2012,35(19):2637-2644
A method was established for the determination of desipramine in biological samples using liquid–liquid–liquid microextraction followed by in‐syringe derivatization and gas chromatography–nitrogen phosphorus detection. The extraction method was based on the use of two immiscible organic solvents. n‐Dodecane was impregnated in the pores of the hollow fiber and methanol was placed inside the lumen of the fiber as the acceptor phase. Acetic anhydride was used as the reagent for the derivatization of the analyte inside the syringe barrel. Parameters that affect the extraction efficiency (composition of donor and acceptor phase, ionic strength, sample temperature, and extraction time) as well as derivatization efficiency (amount of acetic anhydride and reaction time and temperature) were investigated. The limit of detection was 0.02 μg/L with intra and interday RSDs of 2.6 and 7.7%, respectively. The linearity of the method was in the range of 0.2–20 μg/L (r2 = 0.9986). The method was successfully applied to determine desipramine in human plasma and urine. 相似文献
97.
Esmaeil Jafari 《Russian Journal of Electrochemistry》2021,57(6):663-670
Russian Journal of Electrochemistry - Corrosion resistance is one of the essential factors in metal selection and can be enhanced greatly by coatings. The corrosion resistance of the electroless... 相似文献
98.
Jafari Mohammad Farajollahi Amir Gazori Heshmatollah 《Journal of Thermal Analysis and Calorimetry》2021,144(1):167-178
Journal of Thermal Analysis and Calorimetry - In the present study, a new swirling flow generator is studied which aims to enhance the convective heat transfer rate in a heat exchanger tube. This... 相似文献
99.
Safa Raziyeh Soltani Goharrizi Ataallah Jafari Saeed Jahanshahi Javaran Ebrahim 《Journal of Thermal Analysis and Calorimetry》2021,144(6):2497-2514
Journal of Thermal Analysis and Calorimetry - In the present study, double-diffusive mixed convection related to the heat and mass transfer of the solid particles dissolution in a shear flow was... 相似文献
100.
Morphine and noscapine were determined using corona discharge ion mobility spectrometry. The detection limits were 5.6 × 10−11 and 6.7 × 10−11 g for morphine and noscapine, respectively. The linear dynamic ranges of the calibration plots for the compounds were about three orders of magnitude. The method has also been successfully applied for simultaneous determination of the compounds using the standard addition method. 相似文献