检索结果-南通市图书馆

Friction-stir-welded overaged 7020-T6 alloy joint: an investigation on the effect of rotational speed on the microstructure and mechanical properties

在线全文

学校读者我要写书评

暂无评论

International Journal of minerals,metallurgy and materials 2019年第5期26卷 622-633页

作者： m.alipour Behzadi Khalil ranjbar r.Dehmolaei E.Bagherpour materials Science and Engineering Department Faculty of Engineering Shahid Chamran University of Ahvaz Department of mechanical Engineering Doshisha University

Commercial A7020-T6 plates in the overaged state were subjected to friction stir welding with four different tool rotational speeds of 500, 710, 1000, and 1400 r/min and a single traverse feed rate of 40 mm/min. The resultant changes in the welding heat input, microstructure, and the mechanical properties of the joints were investigated. The changes were related to the processes of growth, dissolution, and re-formation of precipitates. The precipitate evolution was examined by differential scanning calorimetry, and the microstructural analysis was conducted using optical, scanning, and transmission electron microscopes. The results showed that the grain size in the stirred zone(SZ) decreased substantially compared with the base metal, but increased with tool rotational speed because of the rise in temperature. We found that the width of the heat-affected zone increased with tool rotational speed. The hardness and the tensile strength in the SZ increased with increasing heat input compared with the base metal in the overaged condition. This recovery in mechanical properties of the joints can be attributed to the dissolution and re-formation of precipitates in the SZ and the thermomechanically affected zone. This process is referred to as an "auto-aging treatment."

关键词： A7020-T6 overaged friction stir welding precipitates rotational speed heat input auto-aging

Improving Plasma Confinement by Controlling Hard X-ray

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2016年第11期33卷 67-70页

作者： N.Hasanvand m.r.riazifar r.alipour S.meshkani m.Ghoranneviss Plasma Physics research Center Science and Research BranchIslamic Azad University

Since runaway electrons and magnetohydrodynamics activity can contribute to serious damage and energy losses in tokamaks, the effect of an external electric field on runaway electrons and hard x-ray spectra is investigated. Parameters such as the plasma current, the hard x-ray photons count and the mean energy of runaway electrons are measured. Positive and negative voltages of 300 V are applied at lOms after the plasma initiation （while the plasma is forming）, at 15ms （while the plasma is stable） and at 20ms （while the plasma is fading away） to attain the most effective time of applying the external electric field. The number of hard x-ray photons has the most changes in the range of O-200 keV when the external electric fields are applied. Also in the duration of 20-30ms of plasma the greatest number of hard x-ray spectra is detected. When the external electric fields are applied, the mean energy of runaway electrons reduces significantly, especially at 15 ms （while the plasma is stab/e）.

关键词： of is that as on in Improving Plasma Confinement by Controlling Hard X-ray by

INVESTIGATION OF THE THICKNESS VArIABILITY AND mATErIAL HETErOGENEITY EFFECTS ON FrEE VIBrATION OF THE VISCOELASTIC CIrCULAr PLATES

在线全文

学校读者我要写书评

暂无评论

Acta mechanica Solida Sinica 2013年第1期26卷 83-98页

作者： m.Shariyat A.A.Jafari m.m.alipour Faculty of mechanical Engineering K.N.Toosi University of Technology

The present study deals with free vibration analysis of variable thickness viscoelastic circular plates made of heterogeneous materials and resting on two-parameter elastic foundations in addition to their edge conditions. It is assumed that the viscoelastic material properties vary in the transverse and radial directions simultaneously. The complex modulus approach is employed in conjunction with the elastic-viscoelastic correspondence principle to obtain the solution. The governing equations are solved by means of a power series solution. Finally, a sensitivity analysis including evaluation of effects of various edge conditions, thickness variations, coefficients of the elastic foundation, and material loss factor and heterogeneity on the natural frequencies and modal loss factors is accomplished.

关键词： viscoelastic variable thickness circular plate natural frequencies elastic foundation material heterogeneity power series solution

SEmI-ANALYTICAL SOLUTION FOr FrEE VIBrATION OF THICK FUNCTIONALLY GrADED PLATES rESTED ON ELASTIC FOUNDATION WITH ELASTICALLY rESTrAINED EDGE

在线全文

学校读者我要写书评

暂无评论

Acta mechanica Solida Sinica 2011年第4期24卷 340-354页

作者： m.Shaban m.m.alipour Faculty of mechanical Engineering Islamic azad University Parand Branch

This paper deals with free vibration analysis of functionally graded thick circular plates resting on the Pasternak elastic foundation with edges elastically restrained against translation and *** equations are obtained based on the first order shear deformation theory（FSDT） with the assumption that the mechanical properties of plate materials vary continuously in the thickness direction.A semi-analytical approach named differential transform method is adopted to transform the differential governing equations into algebraic recurrence *** eigenvalue equation for free vibration analysis is solved for arbitrary boundary *** between the obtained results and the results from analytical method confirms an excellent accuracy of the present ***,comprehensive studies on the FG plates rested on elastic foundation are *** effects of parameters,such as thickness-to-radius,material distribution,foundation stiffness parameters,different combinations of constraints at edges on the frequency,mode shape and modal stress are also investigated.

关键词： free vibration thick circular plates two-parameter elastic foundation elasticallyrestrained edges

Design adaptations in a large and deep urban excavation: Case study

在线全文

学校读者我要写书评

暂无评论

Journal of rock mechanics and Geotechnical Engineering 2019年第2期11卷 389-399页

作者： Amir alipour Abolfazl Eslami Department of Civil and Environmental Engineering Amirkabir University of Technology

In this paper, design, re-design, and performance of a long-standing very deep excavation, which was originally planned to depth of 38 m, are presented. Over-digging was not planned in the original design,thus the reassessment was performed. Two main topics were followed: deepening to increase the maximum depth of an existent excavation from 38 m to 42.5 m, and feasibility for upgrading a predesigned support system from temporary to permanent support system. The geological investigations in the project site illustrated a type of stiff and cemented coarse-grained alluvium. An observational approach with additional geotechnical investigations and in situ tests was applied. Back analyses of stability of an unsupported access ramp, as well as deformation monitoring of walls, were used in order to review geotechnical design parameters that represent the full-scale behavior of the ground. Additional nails and soldier piles together with building mat foundation were implemented as a complementary lateral support in the retaining system. From an engineering point of view, by assuming a corrosion rate of 0.065 mm/a for existent rebars, according to chemical and electrical resistivity tests, the long-term performance of the revised retaining system was verified by static and pseudo-dynamic ultimate limit state analyses. Performance monitoring during the construction shows that the measured deformation is in the lower limit of the prediction.

关键词： Deep excavation Field observations In situ tests Support system Adaptive design Inverse analysis

molecular detection of Leishmania isolated from Cutaneous leishmaniasis patients in Jask County,Hormozgan Province,Southern Iran,2008

在线全文

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical medicine 2012年第7期5卷 514-517页

作者： Koroush Azizi Aboozar Soltani Hamzeh alipour Department of medical Entomology Schools of Health and NutritionShiraz University of Medical SciencesShirazIran Deparment of medical Entomology and Vector Control School of Public HealthTehran University of Medical SciencesTehranIran

Objective:To investigate on patients leishmanial infections in Jask ***: Impression smears were prepared from patients in 2008,all,were chequed for leishmanial infection by microscopy and molecular *** *** was extracted using Proteinase K and Phenol/Chloroform/Isoamyl alcohol *** variable segment on minicircles of kineloplasl DIVA was amplified via a Nested-PCr technique using species-specific primers(LIN r4-LIN 17 -Lin 19).results:A total of 40 smears were prepared from 20 patients,from which,eight samples (40%) were positive for leishman body by microscopic method,while,18 samples(90%) were positive,*** parasite was identified as Leishmania major(L major).Conclusions: Zoonotic or rural cutaneous leishmaniasis is endemic in Jask County whose pathogen is L *** assays using specific primers are very accurate and more sensitive and specific than microscopy which is time consuming and needs master mieroscopists.

关键词： Zoonotic Cutaneous Leishmaniasis Leishmania major Nested PCr Jask Iran

Isolating sorbicilin-producing fungi from Darband cave and evaluating the sorbicilin biomedical applications

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Studies in Fungi 2020年第1期5卷 103-112页

作者： Zareshahi F Abolmaali SH Darvish alipour Astaneh SH Asghari A Dep.for Biotechnology Faculty of BiotechnologySemnan UniversityIran Dep.for Biology Faculty of Basic ScienceSemnan UniversityIran Dep.for Chemistry Faculty of ChemistrySemnan UniversityIran

To evaluate the potential of fungi from Darband cave,Semnan,Iran,for valuable antibacterial and anticancer agents,molecular screening was done against polyketides(PKS);the source for numerous diverse secondary *** were isolated from soil and *** antibacterial activity of the isolates was studied against indicator bacteria by well diffusion agar method,and analyzed by PCr for PKS *** positive strains were compared for toxicity against indicators and A549 *** of antibacterial agents was investigated in 26 days followed by partial purification of the *** layer chromatography(TLC)and High Performance Liquid Chromatography(HPLC)analyses were done to reveal the nature of the toxin(s).The isolates exhibited the antimicrobial activity against Staphylococcus aureus,Bacillus cereus,and Bacillus *** isolates selected for further studies based on the yellow culture broth,the presence of PKS,and antibacterial *** strains were identified as Penicillium chrysogenum using 18s rDNA *** yellow culture,87%identity of the PKS 12/PKS 13,the results of HPLC,and the toxic effects against certain bacteria and A549 cells confirmed the production of the sorbicillinoid in *** strains;DDFCC170 and *** partially-purified antibacterial-anticancer agents named as AnBa170 and AnBa186 exhibited bactericide effect on *** and *** compounds killed A549 cells with an IC_(50) value of 0.25μm and 0.22μm ***170 and AnBa186 are attractive for pharmaceutical *** on the literature,the cytotoxicity of sorbicillinoids against tumor cells and bacteria is related to their oxidation capacity.

关键词： Antibacterial Penicillium chrysogenum PKS Sorbicillin

Hydrogeochemistry of seasonal variation of Urmia Salt Lake

维普期刊数据库评论

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 Journal Of Geochemistry 2006年第B08期25卷 193-194页

作者： Samad alipour Geology Dept Urmia University Urmia Iran

Treatment of moderate to severe keratoconus with 6-mm Intacs SK

在线全文

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2012年第4期5卷 513-516页

作者： Sasan Niknam mehrdad Shamshiri Seyed Sahabaldin Shahrzad Abbas alipour mohammad Bagher rajabi mohammad Taher rajabi Cornea Unit Dr Khodadoust Eye HospitalShiraz Iran Department of Ophthalmology Dr. Khodadoust Eye HospitalShiraz Iran Department of Ophthalmology Khalili HospitalShiraz Iran Department of Epidemiology and Statistics Faculty of Nutrition and HealthShiraz Iran Department of Ophthalmology Eye Research Center Farabi Eye Hospital Tehran University of Medical SciencesTehran Iran

·AIm:To evaluate the effect of Intacs SK corneal ring segment implant for treatment of patients with moderate to severe keratoconus, who have clear central cornea and cannot tolerate contact lens. ·mETHODS:In this prospective, non-comparative, intervent- ional case series study performed in Dena Hospital, Shiraz, Iran, thirty-seven eyes of thirty-six patients with moderate to severe keratoconus, clear central cornea, and contact lens intolerance were enrolled and underwent Intacs SK corneal ring segment implantation. Preoperatively, uncorrected distance visual acuity (UCDVA), best-corrected distance visual acuity (BCDVA), central corneal thickness(CCT) and average keratometry (Av-K) were measured and compared with post-operative results at one week, one month, three months, and six months. ·rESULTS:mean preoperative UCDVA and BCDVA were (1.32±0.31) logmAr and (1.07±0.27) logmAr, respectively. Av-K was (52.13±0.39)D, and the CCT was (432±39.5)μm. Post-operative examinations showed a clinically significant improvement in both UCDVA and BCDVA (P re was also a significant effect based on the time of assessment on both UCDVA and BCDVA and both parameters had a continuous improvement during the follow-up period. Three months after operation there was a statistical significant reduction of Av-K (P =0.0001), but there were no significant changes in CCT (P =0.149). ·CONCLUSION:Intacs SK corneal ring segment implants seem to be a safe and effective treatment option for patients who have keratoconus, clear central cornea, and contact lens intolerance.

关键词： keratoconus Intacs myopia