检索结果-南通市图书馆

International Journal of Mining Science and Technology 2013年第5期23卷 717-724页

作者： Aghajani Shahrivar Alireza Soltani Goharrizi Ataallah Ebrahimzadeh Gheshlaghi Majid Sarafi Amir Razmirad mohammad Abdollahi hadi Department of Chemical Engineering University of Shahid Bahonar School of Mining Engineering College of EngineeringUniversity of Tehran

This study discussed the application of response surface methodology(RSM)and central composite rotatable design(CCRD)for modeling and optimization of the influence of some operating variables on the performance of a lab scale thickener for dewatering of tailing in the flotation *** thickener operating variables,namely feed flowrate,solid percent,flocculant dosage and feedwell height were changed during the tests based on *** ranges of values of the thickener variables used in the design were a feed flowrate of 9–21 L/min,solid percent of 8%–20%,flocculant dosage of 1.25–4.25 g/t and feedwell height of 16–26 cm.A total of 30 thickening tests were conducted using lab scale thickener on flotation tailing obtained from the Sarcheshmeh copper mine,*** underflow solid percent and bed height were expressed as functions of four operating parameters of *** values were found to be in good agreement with experimental values(R2values of 0.992 and 0.997 for underflow solid percent and bed height,respectively).This study has shown that the RSM and CCRD could effciently be applied for the modeling of thickener for dewatering of flotation tailing.

关键词： Response surface methodology Central composite rotatable design Modeling Thickener

Dispersion compensation using high-positive dispersive optical fibers

在线全文

学校读者我要写书评

暂无评论

Chinese Optics Letters 2017年第3期15卷 64-68页

作者： Mohammand hadi Farokh Marvasti mohammad Reza Pakravan Electrical Engineering Department Sharif University of Technology Tehran 113658639 Iran

The common and traditional method for optical dispersion compensation is concatenating the transmitting optical fiber by a compensating optical fiber having a high-negative dispersion coefficient. In this Letter, we take the opposite direction and show how an optical fiber with a high-positive dispersion coefficient is used for dispersion compensation. Our optical dispersion compensating structure is the optical implementation of an iterative algorithm in signal processing. The proposed dispersion compensating system is constructed by cascading a number of compensating sub-systems, and its compensation capability is improved by increasing the number of embedded sub-systems. We also show that the compensation capability is a trade-off between the transmission length and bandwidth. We use the simulation results to validate the performance of the introduced dispersion compensating module. Photonic crystal fibers with high-positive dispersion coefficients can be used for constructing the proposed optical dispersion compensating module.

关键词： Dispersion compensation using high-positive dispersive optical fibers high

Simultaneous determination of cysteamine and folic acid in pharmaceutical and biological samples using modified multiwall carbon nanotube paste electrode

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2012年第2期23卷 237-240页

作者： Ali Taherkhani Hassan Karimi-Maleh Ali A.Ensafi hadi Beitollahi Ahmad Hosseini mohammad A.Khalilzadeh Hassan Bagheri Department of Physics Takestan Branchlslamic Azad UniversityTakestanlran Department of Chemistry Majlesi BranchIslamic Azad UniversityIsfahanIran Environment Department Research Institute of Environmental SciencesInternational Center for ScienceHigh Technology and Environmental SciencesKermanIran Department of Chemistry Qaemshahr BranchIslamic Azad UniversityQaemshahrlran Department of Chemistry Takestan Branchlslamic Azad UniversityTakestanlran

A carbon paste electrode（CPE） chemically modified with multiwall carbon nanotubes and ferrocene（FC） was used as a selective electrochemical sensor for the simultaneous determination of trace amounts of cysteamine（CA） and folic acid（FA）.This modified electrode showed very efficient electrocatalytic activity for the anodic oxidation of *** peak current of differential pulse voltammograms of CA and FA increased linearly with their concentration in the ranges of 0.7-200μmol/L CA and 5.0- 700μmol/L *** detection limits for CA and FA were 0.3μmol/L and 2.0μmoI/L,*** diffusion coefficient（D） and transfer coefficient（α） of CA were also *** conditions are sufficient to allow determination of CA and FA both individually and simultaneously.

关键词： Cysteamine Folic acid Carbon nanotube paste electrode Voltammetry

Modeling and optimization of low-grade Mn bearing ore leaching using response surface methodology and central composite rotatable design

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2012年第9期22卷 2295-2305页

作者： Dariush AZIZI Sied Ziaedin SHAFAEI mohammad NOAPARAST hadi ABDOLLAHI School of Mining University College of EngineeringUniversity of TehranTehranIran

The application of leaching process to extracting Mn from a low-grade manganese ore was investigated using a software based design of experiments. Four main parameters, i.e. sulfuric acid concentration, oxalic acid concentration, time and temperature were considered in a central composite response surface design. The recoveries of Mn and Fe were selected as response of design. The optimum conditions under which the Mn and Fe recoveries were the highest and the time and temperature were the lowest were determined using statistical analysis and analysis of variance （ANOVA）. The results showed that Mn and Fe recoveries were 93.44% and 15.72% under the optimum condition, respectively. Also, sulfuric acid concentration was the most effective parameter affecting the process. The amounts of sulfuric and oxalic acid were obtained to be 7% and 42.50 g/L in optimum condition and the best time and temperature were 65 min and 63 ℃.

关键词： response surface methodology leaching manganese optimization modeling

Optimal design and applicability of electric power steering system for automotive platform

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2019年第4期26卷 839-851页

作者： Abolfazl KHALKHALI mohammad Hassan SHOJAEEFARD Masoud DAHMARDEH hadi SOTOUDEH Automotive Simulation and Optimal Design Research Laboratory School of Automotive EngineeringIran University of Science and Technology

The ongoing need for better fuel economy and lower exhaust pollution of vehicles has increased the employment of electric power steering(EPS)in *** design of EPS for a product family reduces the development and fabrication costs *** this paper,the TOPSIS method along with the NSGA-Ⅱis employed to find an optimum family of EPS for an automotive platform.A multi-objective optimization problem is defined considering road feel,steering portability,RMS of Ackerman error,and product family penalty function(PFPF)as the conflicting objective *** results for the single objective optimization problems and the ones for the multi-objective optimization problem,as well as two suggested trade-off design points are presented,compared and *** the two suggested points,performance at one objective function is deteriorated by about 1%,while the commonality is increased by 20%–40%,which shows the effectiveness of the proposed method in first finding the non-dominated design points and then selecting the trade-off among the obtained *** results indicate that the obtained trade-off points have superior performance within the product family with maximum number of common parts.

关键词： product family optimization optimal platform design NSGA-Ⅱ TOPSIS electric power steering

Can Campylobacter jejuni play a role in development of celiac disease? A hypothesis

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2007年第35期13卷 4784-4785页

作者： Behnam Sabayan Farzaneh Foroughinia mohammad hadi Imanieh Student Research Center of Shiraz University of Medical Sciences ShirazIran Gastrohepatology Research Center Department of PediatricsShiraz University of Medical SciencesShirazIran

Celiac disease （CD） is an entropathy with malabsortive condition in which an allergic reaction to the cereal grain-protein （gluten） causes small intestine rnucosal injury. CD is a multifactorial disorder in which both genetic and environmental factors contribute to the disease development. Mechanisms have been described to explain the pathology of CD. T cells specific for multiple gluten peptides are found in virtually all patients. Generation of such a broad T cell response may be a prerequisite for disease development. CD is associated with multiple extraintestinal presentations, including neurological deficits. Recent studies have shown a significant correlation between anti-ganglioside antibodies and neurological disorders in patients with underlying CD. Gangliosides are glycosphingolipids which are abundant in nervous system and in other tissues including gastrointestinal tract. It is not known what triggers the release of anti-ganglioside antibodies in people with gluten sensitivity. But, the mechanism is likely to involve the intestinal immune system response to ingested gliadin, a component of wheat gluten. Studies showed that mechanisms different from gluten exposure may be implicated in antibody formation, and other environmental factors may also exist. In addition, considering the fact that genetic predisposition dysregulating mucosal immune responses in the presence of certain environmental triggers like gastrointestinal infections may be strong etiological factors for developing chronic intestinal inflammation including CD, the hypothesis raised in our mind that antiganglioside antibody formation in CD may play a role not only in development of neurological complications in celiac patients, but also in development of CD itself. As presence of Campylobacter jejuni in other diseases with antigangliosides antibody formation has been established, we propose the possible role of Campylobacter jejuni in development of CD in association with other genetic and

关键词： Celiac disease Gangliosides Campylobacter jejuni Molecular mimicry

Metformin alleviates cholestasis-associated nephropathy through regulating oxidative stress and mitochondrial function

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Liver Research 2021年第3期5卷 171-180页

作者： mohammad Mehdi Ommati Hamidreza mohammadi Khadijeh Mousavi Negar Azarpira Omid Farshad Reyhaneh dehghani Asma Najibi Sedigheh Kamran Hossein Niknahad Reza Heidari College of Life Sciences Shanxi Agricultural UniversityTaiguShanxiChina Pharmaceutical Sciences Research Center Shiraz University of Medical SciencesShirazIran Department of Pharmacology and Toxicology School of PharmacyShiraz University of Medical SciencesShirazIran Transplant Research Center Shiraz University of Medical SciencesShirazIran Department of Chemistry Payame Noor UniversityTehranIran

Background and aim:Cholestasis-associated renal injury or cholemic nephropathy(CN)is a serious clinical *** studies mentioned that oxidative stress and mitochondrial impairment play a role in *** is no specific pharmacological intervention for *** is an anti-diabetic drug administered for *** the other hand,novel pharmacological properties have emerged for this *** effect of metformin on oxidative stress parameters has been well-recognized in different experimental *** has also been found that metformin positively affected mitochondrial *** current study aimed to evaluate the effects of metformin in an animal model of ***:Rats underwent bile duct ligation(BDL)and were treated with metformin(250 and 500 mg/kg)for 14 consecutive *** weeks after the BDL operations,urine,serum,and kidney samples were collected and ***:Markers of oxidative stress,including reactive oxygen species(ROS)formation,lipid peroxida-tion,protein carbonylation,depleted antioxidant capacity,and decreased glutathione(GSH)levels were detected in BDL ***,mitochondrial indices,including adenosine triphosphate(ATP)level,dehydrogenase activity,mitochondrial membrane potential,and mitochondrial permeability,were impaired in the kidney of cholestatic *** histopathological alterations in cholestatic animals included tubular degeneration and interstitial inflammation,cast formation,and *** was found that metformin significantly alleviated oxidative stress and improved mitochondrial indices in the kidney of cholestatic *** histopathological alterations were also mitigated in metformin-treated ***:Metformin could be a candidate for managing *** nephroprotective role of metformin is primarily associated with its effects on oxidative stress parameters and mitochondrial function.

关键词： Metformin Bile acids Cholestasis Cirrhosis Oxidative stress Mitochondrial function Energy crisis Cholemic nephropathy(CN) Renal failure

Optimal Control Strategy for a Fully Determined HIV Model

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Intelligent Control and Automation 2010年第1期1卷 15-19页

作者： mohammad Shirazian mohammad hadi Farahi Department of Applied Mathematics Ferdowsi University of Mashhad The Center of Excellence in Modeling and Computations in Linear and Nonlinear Systems Ferdowsi University of Mashhad

This paper shows how mathematical methods can be implemented to formulate guidelines for clinical testing and monitoring of HIV/AIDS disease. First, a mathematical model for HIV infection is presented which the measurement of the CD4+T cells and the viral load counts are needed to estimate all its parameters. Next, through an analysis of model properties, the minimal number of measurement samples is obtained. In the sequel, the effect of Reverse Transcriptase enzyme Inhibitor (RTI) on HIV progression is demonstrated by using a control function. Also the total cost of treatment by this kind of drugs has been minimized. The numerical results are obtained by a numerical method in discretization issue, called AVK.

关键词： HIV/AIDS Mathematical Modeling System Identification Control Theory Immunotherapy

H pylori infection among 1000 southern Iranian dyspeptic patients

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2006年第34期12卷 5479-5482页

作者： Mahmood Reza Hashemi mohammad Rahnavardi Bavand Bikdeli Mohsen dehghani Zahedani Department of Gastroenterology Hormozgan University of Medical Sciences Bandarabbas Artesh University of Medical Sciences Tehran Iran Educational Development Center Artesh University of Medical Sciences Tehran Iran Department of Pathology Bandarabbas University of Medical Sciences Bandarabbas Iran

AIM: To describe the frequency of H pylori infection among 1000 southern Iranian dyspeptic patients. METHODS: A prospective study was performed in a referral hospital in south of Iran from 1999 to 2005. One thousand dyspeptic patients (518 males, mean ± SD age of 49.12 ± 12.82 years) consecutively underwent upper gastrointestinal endoscopy. Multiple gastric antral biopsy samples were taken from all patients for rapid urease test and histopathologic examination (96.9% satisfactory samples). Patients were considered H pylori-infected if one or both tests were positive. RESULTS: Six hundred and seventy-one patients (67.1%, 95% confidence interval [CI]: 64.2%-70.0%) were H pylori-infected. H pylori positivity was significantly more frequent in patients with peptic ulcer disease (PUD) than in those with non-ulcer dyspepsia (P < 0.001). Male-to-female ratio for duodenal and gastric ulcers was 2.7:1 and 1.5:1, respectively. Moreover, the duodenal- to-gastric ulcer ratio was 1.95:1. The frequency of H pylori infection among those with endoscopic diagnosis of gastritis, duodenal ulcer, gastric ulcer, and normal mucosa was 70.1% (398/568), 86.2% (150/174), 71.9% (64/89), and 33.5% (54/161), respectively. H pylori infection, male sex, and older age were independently associated with PUD in multivariate analysis. H pylori positivity was associated with chronic gastritis, and chronic active gastritis with odds ratios of 34.21 (95% CI: 12.19%-96.03%) and 81.21 (95% CI: 28.85%-228.55%), respectively. CONCLUSION: H pylori and PUD are highly frequent in dyspeptic patients from south of Iran. H pylori is a cardinal risk factor for chronic active or inactive gastritis.

关键词： Dyspepsia H pylori Iran

Experimental Study on Improved Engineered Cementitious Composite Using Local Material

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Materials Sciences and Applications 2018年第3期9卷 315-329页

作者： Fariborz Nateghi-A mohammad Hossein Ahmadi Ayoub dehghani International Institute of Earthquake Engineering and Seismology Tehran Iran Persian Gulf University Boushehr Iran

Engineered Cementitious Composite (ECC) is a cement based material with ultra-high ductility and strength in tension. This material is a kind of highperformance fiber-reinforced cementitious composite materials (HPFRCCs) reinforced with short fibers and characterized by tight multiple cracking. These characteristics of ECC make it applicable to increase the capacity and the ductility of structural elements so that structural design is economic and sustainable. This paper presents an extended evaluation of Improved Engineered Cementitious Composites (IECC) for the use in the strengthening of masonry in filled reinforced concrete frames. IECC is a mixture of cement, fly ash, water, sand, quartz powder and poly-vinyl alcohol fibers with a better quality of tensile strain rather than common ECC. Two types of fine sand and quartz powder used in this study as filler to improve ECC behavior. Also, to show the effect of fly ash on IECC properties, five different mixtures were considered with various fly ash ratios. Different mixtures of IECC using fine aggregates produced in Iran were selected to find out how the aggregates and fly ash would affect IECC performance. The results show that the optimized mixture has the best characteristics including tensile strength and strain. Also, three-dimensional diagrams were used to compare the properties of different mixtures of IECC more effectively and to represent the influence of the range of fly ash ratios so that it can be opted based on design objectives such as ECC properties, costs and structural parameters and demands. These diagrams show the behavior of IECC which its fly ash content ratio in the binder is 50% to 67%.

关键词： Improved Engineered Cementitious Composites Optimization Experimental Study Local Material