检索结果-南通市图书馆

Chinese Chemical Letters 2013年第3期24卷 195-198页

作者： abolfazl Ziarati Javad Safaei-Ghomi Sahar Rohani Department of Organic Chemistry Faculty of ChemistryUniversity of KashanKashan 51167Islamic Republic of Iran

An efficient and multicomponent method has been developed for the synthesis of functionalized tricarboxamides at room temperature using CuI nanoparticles as catalyst. This method involved fivecomponent coupling reactions of Meldrum＇s acid, isocyanides with aromatic aldehydes and amines at room temperature. Atom economy, wide range of products, excellent yields in short time and mild reaction conditions are some of the important features of this protocol. Notably, this catalyst could be recycled and reused for several times without significantly decreasing the catalytic activity.

关键词： TricarboxamidesCopper iodide nanoparticlesMulticomponent reactionsReusable catalyst

On the accuracy of higher order displacement discontinuity method(HODDM) in the solution of linear elastic fracture mechanics problems

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2016年第11期23卷 2941-2950页

作者： abolfazl Abdollahipour Mohammad Fatehi Marji Alireza Yarahmadi Bafghi Javad Gholamnejad Faculty of Mining and Metallurgical Engineering Yazd University

The higher order displacement discontinuity method(HODDM) utilizing special crack tip elements has been used in the solution of linear elastic fracture mechanics(LEFM) problems. The paper has selected several example problems from the fracture mechanics literature(with available analytical solutions) including center slant crack in an infinite and finite body, single and double edge cracks, cracks emanating from a circular hole. The numerical values of Mode Ⅰ and Mode Ⅱ SIFs for these problems using HODDM are in excellent agreement with analytical results(reaching up to 0.001% deviation from their analytical results). The HODDM is also compared with the XFEM and a modified XFEM results. The results show that the HODDM needs a considerably lower computational effort(with less than 400 nodes) than the XFEM and the modified XFEM(which needs more than 10000 nodes) to reach a much higher accuracy. The proposed HODDM offers higher accuracy and lower computation effort for a wide range of problems in LEFM.

关键词： accuracy higher order displacement discontinuity method LEFM mode Ⅰ stress intensity factor mode Ⅱ stress intensity factor

Multi-objective energy management of island microgrids with D-FACTS devices considering clean energy, storage systems and electric vehicles

在线全文

学校读者我要写书评

暂无评论

Clean Energy 2023年第5期7卷 1046-1057页

作者： Mahyar Moradi Mohamad Hoseini Abardeh Mojtaba vahedi Nasrin Salehi Azita Azarfar Department of Electrical Engineering Shahrood BranchIslamic Azad UniversityShahroodIran Department of Basic Sciences Shahrood BranchIslamic Azad UniversityShahroodIran

The development of microgrids is progressing due to intelligent load demands,clean energy,batteries and electric *** presence of such systems in microgrids causes power balance inconsistency,leading to increased power losses and deviation in *** this pa-per,a mixed-integer non-linear programming model is proposed for modelling island microgrid energy management considering smart loads,clean energy resources,electric vehicles and ***,a flexible distributed AC transmission system device is proposed to prevent voltage deviation and reduce power losses.A scenario-based multi-objective function has been proposed to decrease energy losses and voltage deviations and energy outages of clean energy resources,reduce emissions from fossil-fired distributed generation and finally decrease load outages to reduce the vulnerability of the islanded *** the proposed mixed-integer non-linear model and the high number of variables and constraints,a modified evolutionary algorithm based on particle swarm optimization has been proposed to solve the proposed model,which can be more efficient than other algorithms to achieve global optimal *** model presented is implemented on a 33-node island microgrid and the results illustrate that the proposed algorithm and model are effective in reducing energy losses and voltage deviation,as well as reducing the vulnerability of the *** simulation results demonstrate that the proposed approach can lead to significant improvements in the performance of the ***,the ap-proach can result in a 27%reduction in losses,a 6%reduction in pollution and a 31%improvement in ***,the approach allows maximum utilization of renewable energy sources,making it a promising solution for sustainable energy management.

关键词： microgrid D-FACTS clean energy battery electric vehicles evolutionary algorithm

Co-optimization of integrated energy systems in the presence of renewable energy,electric vehicles,power-to-gas systems and energy storage systems with demand-side management

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Clean Energy 2023年第2期7卷 426-435页

作者： Mahroo Sattar Mahmoud Samiei Moghaddam Azita Azarfar Nasrin Salehi Mojtaba vahedi Department of Electrical Engineering Shahrood BranchIslamic Azad UniversityShahroodIran Department of Electrical Engineering Damghan BranchIslamic Azad UniversityDamghanIran Department of Basic Sciences Shahrood BranchIslamic Azad UniversityShahroodIran

With the widespread penetration of renewable energy sources and energy storage systems,the problem of energy management has received increasing *** of the systems that network owners consider today is the power-to-gas(P2G)*** system causes surplus electricity generated from renewable energy resources or batteries in the network to be converted into gas and sold to the gas *** reasons for the existence of gas distributed generation resources and P2G systems cause the two power and gas networks to *** management and profit making considering these two networks,as a co-optimization of integrated energy systems,is a topic that has been discussed in this study to achieve the best optimal *** the production of renewable energy resources and the purchase price of energy are uncertain,a scenario-based method has been chosen for ***-side management is also one of the important problems in optimal operation of the electricity network,which can have a significant impact on reducing peak load and increasing *** this paper,a mixed-integer quadratic programming model for co-optimization of electric distribution and gas networks in the presence of distributed generation resources,P2G systems,storage facilities,electric vehicles and demand-side management is *** 33-bus distribution network is intended to analyse the proposed *** results of different scenarios show the efficiency of the proposed *** key points are deduced from the obtained results:(i)demand-side management is able to reduce the peak load of the network,(ii)the presence of renewable resources and batteries can cause the network to convert excess electricity into gas and sell it to the gas network in the market and(iii)distributed generation can reduce the purchase of energy from the upstream network and cause a 36% reduction in the cost function.

关键词： optimization linear programming integrated systems power-to-gas scenario-based model electricity distribution

Mechanochemical leaching of chalcopyrite concentrate by sulfuric acid

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 Minerals,Metallurgy and Materials 2016年第4期23卷 380-388页

作者： Farhad Khorramshahi Mohammadabad Sina Hejazi Jalil Vahdati khaki abolfazl Babakhani Materials and Metallurgical Engineering Department Faculty of Engineering Ferdowsi University of Mashhad Materials and Metallurgical Engineering Department Faculty of Engineering University of Tehran

This study aimed to introduce a new cost-effective methodology for increasing the leaching efficiency of chalcopyrite concentrates at ambient temperature and pressure. Mechanical activation was employed during the leaching（mechanochemical leaching） of chalcopyrite concentrates in a sulfuric acid medium at room temperature and atmospheric pressure. High energy ball milling process was used during the leaching to provide the mechanochemical leaching condition, and atomic absorption spectroscopy and cyclic voltammetry were used to determine the leaching behavior of chalcopyrite. Moreover, X-ray diffraction and scanning electron microscopy were used to characterize the chalcopyrite powder before and after leaching. The results demonstrated that mechanochemical leaching was effective; the extraction of copper increased significantly and continuously. Although the leaching efficiency of chalcopyrite was very low at ambient temperature, the percentages of copper dissolved in the presence of hydrogen peroxide（H2O2） and ferric sulfate（Fe2（SO4）3） after 20 h of mechanochemical leaching reached 28% and 33%, respectively. Given the efficiency of the developed method and the facts that it does not require the use of an autoclave and can be conducted at room temperature and atmospheric pressure, it represents an economical and easy-to-use method for the leaching industry.

关键词： chalcopyrite mechanical activation mechanochemical leaching sulfuric acid cyclic voltammetry

Facile synthesis, morphology and structure of Dy_2O_3 nanoparticles through electrochemical precipitation

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2016年第8期35卷 637-642页

作者： Taher Yousefi Meisam Torab-Mostaedi abolfazl Aghaei Hossein Ghasemi-Mobtaker Nuclear Fuel Cycle Research School Nuclear Science and Technology Research Institute

The aim of this research was to introduce a new, facile and simple method for synthesis of Dy203 nanostructures at room temperature. For the first time, galvanostatic electrodeposition was used to synthesize Dy203 particles, and the influence of the current density on the structure and morphology of the product was studied. The samples were characterized by X-ray diffraction （XRD）, transmission electron microscopy （TEM） and Brunauer-Emmett-Teller （BET）. The results show that the current density has little effect on the chemical composi- tion but great effect on the structure and morphology of the samples. The average size of the particles decreases as the applied current density increases. The grain size of as- prepared samples decreases from 500 to 70 nm when the current density increases from 0.5 to 6.0 ***-a. To obtain oxide product, the as-prepared samples were heat- treated at 1,000 ℃. The results show that the heat-treated samples have smaller particles. The XRD results show that the similar patterns are observed in the samples synthesized at different current densities, and the only difference from the JCPDS card is the ratio of peak intensities. With the increase in the current density, a decrease in the current efficiency is observed.

关键词： Dy203 Nanoparticle Electrodeposition Nanostructures Rare earth

Impact of an educational intervention on medical records documentation

在线全文

学校读者我要写书评

暂无评论

World Journal of Emergency Medicine 2018年第2期9卷 136-140页

作者： Hojat Sheikhmotahar vahedi Minasadat Mirfakhrai Elnaz Vahidi Morteza Saeedi Emergency Medicine Research Center Emergency Medicine Department Shariati Hospital Tehran University of Medical Sciences Emergency Medicine Department Shariati Hospital Tehran University of Medical Sciences

BACKGROUND: Inaccurate and incomplete documentation can lead to poor treatment and medicolegal consequences. Studies indicate that teaching programs in this field can improve the documentation of medical records. The study aimed to evaluate the effect of an educational workshop on medical record documentation by emergency medicine residents in the emergency ***: An interventional study was performed on 30 residents in their first year of training emergency medicine(PGY1), in three tertiary referral hospitals of Tehran University of Medical Sciences. The essential information that should be documented in a medical record was taught in a 3-day-workshop. The medical records completed by these residents before the training workshop were randomly selected and scored(300 records), as was a random selection of the records they completed one(300 records) and six months(300 records) after the ***: Documentation of the majority of the essential items of information was improved significantly after the workshop. In particular documentation of the patients' date and time of admission, past medical and social history. Documentation of patient identity, requests for consultations by other specialties, first and final diagnoses were 100% complete and accurate up to 6 months of the ***: This study confirms that an educational workshop improves medical record documentation by physicians in training.

关键词： Medical records documentation Emergency Medicine First degree residents

Reducing Labor Anxiety with Auriculotherapy:A Randomized Clinical Trial Study

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Integrative Medicine 2022年第5期28卷 440-444页

作者： Katayon Vakilian Mehrnoush Ghaemmaghami Narges Sheikhganbari Fatemeh Shabani Masoomeh vahedi Department of Midwifery School of MedicineTraditional and Complementary Medicine Research CenterArak University of Medical SciencesArak(***)Iran Medical School Arak University of Medical SciencesArak(***)Iran Nursing-Midwifery School Iran University of Medical SciencesTehran(***)Iran

Objectives:To investigate the effect of auriculotherapy on reducing labor ***:In this randomized clinical trial,166 nulliparous pregnant women admitted to the Labor Ward of Izadi Hospital in Qom,Iran were included and assigned to two groups by randomized block *** the intervention group(83 cases),auriculotherapy in"Shenmen,Thalamic,Zero,Brain,and Brain stem"was performed in dilatations of 4,6 and 8 cm,between the contractions for 30 s in both ears at interval 1 *** the control group received routine *** Spielberger Inventory were completed pre-and ***:The auriculotherapy was effective to reduce anxiety state in the intervention group compared to the control group(P=0.001).The score of state anxiety in the intervention group reduced for 7.0,8.0 and 11.0 U in 4,6,and 8 cm dilatations after the *** score of trait anxiety in the intervention group reduced for 3.8,4.0 and 8.3 U in 4,6,and 8 cm dilatations after the *** was no significant difference of delivery mode and newborns’weight and Apgar score between groups(P>0.05).No adverse postpartum outcome such as hemorrhage has been observed in both ***:Since most women are anxious during labor,it seems that auriculotherapy can be an easy and safe method to reduce labor anxiety.(Trial registration ***20121230011944 n4)

关键词： auriculotherapy childbirth pain anxiety

Sensitivity analysis of energy inputs and economic evaluation of pomegranate production in Iran

在线全文

学校读者我要写书评

暂无评论

Information Processing in Agriculture 2018年第1期5卷 114-123页

作者： Mehdi Esmailpour Troujeni Mehdi Khojastehpour Adel vahedi Bagher Emadi Department of Biosystems Engineering Ferdowsi University of MashhadMashhadIran Agricultural Engineering Research Institute(AERI) Agricultural Research Education and Extension Organization(AREEO)KarajIran

The aim of this research was to investigate the energy use and costs of pomegranate production in Behshahr city(Mazandaran province)of *** required data were gathered by questionnaire and face to face interviews with 83 pomegranate ***-Douglas model and sensitivity analysis were employed for energy flows modeling of the production *** total energy inputs and energy output of production were determined to be 11195.06 and 13276.56 MJ ha1,and two inputs of diesel fuel and chemical fertilizers with the shares of 45.81 and 23.47%,were the highest energy consumers for pomegranate *** use efficiency,energy productivity and net energy were 1.18,2081.50 MJ ha1 and 0.62 kg MJ1,*** results of Cobb-Douglas model showed that the effect of the energy inputs including human labor,biocides,chemical fertilizers,farmyard manure,electricity and water for irrigation on pomegranates yield were positive,while the effects of diesel fuel and agricultural machinery were negative on the pomegranate *** sensitivity analysis results of energy inputs showed that with the increase of one MJ in the energy input of water for irrigation and chemical fertilizers,the yield was increased to 3.12 and 1.42 kg,*** with the increase of one MJ in diesel fuel and agricultural machinery inputs,the yield was decreased to 0.67 and 0.47 kg,*** fuel as the most used energy input in the production accounted for 0.85%of variable costs and the benefit to cost ratio was determined to be 5.57.

关键词： Benefit to cost Cobb-Douglas Energy modeling Energy pattern Pomegranate

Numerical simulation of fatigue crack propagation in heterogeneous geomaterials under varied loads using displacement discontinuity method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2023年第3期15卷 702-716页

作者： Rezvan Alizadeh Mohammad Fatehi Marji abolfazl Abdollahipour Mehdi Pourghasemi Sagand Department of Mining and Metallurgical Engineering Faculty of EngineeringYazd UniversityYazdIran School of Mining Engineering College of EngineeringUniversity of TehranTehranIran

Heterogeneous brittle geomaterials are highly susceptible to cyclic *** contain inherent flaws and cracks that grow under fatigue loads and lead to *** study presents a numerical model for analyzing fatigue in these materials based on the two-dimensional(2D)boundary element method and linear elastic fracture *** process is formulated by coupling the displacement discontinuity method with the incorporation technique of dissimilar regions and the governing equations of *** heterogeneous media are assumed to consist of materials with different properties,and the interfaces are assumed to be completely *** addition,the domains include multiple cracks exposed to constant and variable amplitude cyclic *** stress intensity factor is a crucial parameter in fatigue analysis,which is determined using the displacement field around crack *** incremental crack growth scheme is applied to calculating the fatigue *** growth rate values are employed to estimate the length of crack extension when there are multiple *** interaction between cracks is considered,which also includes the coalescence ***,various structures under different cyclic loads are examined to evaluate the accuracy of this *** results demonstrate the efficiency of the proposed approach in modeling fatigue crack growth and life *** behavior of life curves for the heterogeneous domain was as *** curves illustrate the breakpoints caused by utilizing discrete incremental life *** these points,the trend of the curves changed with the material properties and fatigue characteristics of the new material around the crack tips.

关键词： Fatigue life Crack coalescence Interface Incorporation technique Variable amplitude loading