检索结果-南通市图书馆

Pyrolysis of olive residue/low density polyethylene mixture：Part Ⅰ Thermogravimetric kinetics

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

燃料化学学报 2008年第6期36卷 672-678页

作者： ABOULKAS A e1 HARFI K el BOUADILI A Laboratoire de Recherche sur la Reactivites des Materiaux et l Optimisation des Procedes ＂ReMATOP＂ Departement de chimie Faculte des Sciences Semlalia Universite Cadi Ayyad BP 2390 40001 Marrakech Maroc departement de chimie Faculte polydisciplinaire de Beni-Mellal Universite Sultan Moulay Slimane BP 592 23000 Beni-Mellal Maroc Laboratoire de Chimie Organique et Analytique Departement de chimie Faculte des Sciences et Techniques de Beni-Mellal Universite Sultan Moulay Slimane BP 523 23000 Beni-Mellal Maroc

This paper demonstrates the thermal pyrolysis of olive residue,low density polyethylene(LDPe) and olive residue/LDPe mixture in an inert atmosphere of N2 using thermogravimetric analysis(TGA).Measurements were carried out in the temperature range 300K^973K at heating rates of 2K/min,10K/min,20K/min and 50K/*** on the results obtained,three temperature regimes were selected for studying the non-isothermal kinetics of olive residue/LDPe *** first two were dominated by the olive residue pyrolysis,while the third was linked to the LDPe pyrolysis,which occurred at much higher *** between the experimental and calculated TG/DTG profiles were considered as a measurement of the extent of interactions occurring on *** maximum degradation temperatures of each component in the mixture were higher than those the individual components;thus an increase in thermal stability was *** kinetic parameters associated with thermal degradation were determined using Friedman isoconversional method.

关键词：高温分解反应低密度聚乙烯动力学 LDPe

Occurrence mechanism of silicate and aluminosilicate minerals in Sarcheshmeh copper flotation concentrate

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2009年第5期16卷 494-499页

作者： H.R.Barkhordari1 e.Jorjani1 A.eslami M.Noaparast Mining engineering department Science and Research BranchIslamic Azad UniversityPoonakHesarakTehranIran R&D Division-Sarcheshmeh Copper Complex RafsanjanIran School of Mining engineering University College of EngineeringUniversity of TehranTehranIran

The Sarcheshmeh copper flotation circuit is producing 5× 10^4 t copper concentrate per month with an averaging grade of 28% Cu in rougher, cleaner and recleaner stages. In recent years, with the increase in the open pit depth, the content of aluminosilicate minerals increased in plant feed and subsequently in flotation concentrate. It can motivate some problems, such as unwanted consumption of reagents, decreasing of the copper concentrate grade, increasing of Al2O3 and SiO2 in the copper concentrate, and needing a higher temperature in the smelting process. The evaluation of the composite samples related to the most critical working period of the plant shows that quartz, illite, biotite, chlorite, orthoclase, albeit, muscovite, and kaolinite are the major Al2O3 and SiO2 beating minerals that accompany chalcopyrite, chalcocite, and covellite minerals in the plant feed. The severe alteration to clay minerals was a general rule in all thin sections that were prepared from the plant feed. Sieve analysis of the flotation concentrate shows that Al2O3 and SiO2 bearing minerals in the flotation concentrate can be decreased by promoting the size reduction from 53 to 38 μm. Interlocking of the Al2O3 and SiO2 bearing minerals with chalcopyrite and chalcocite is the occurrence mechanism of silicate and aluminosilicate minerals in the flotation concentrate. The dispersed form of interlocking is predominant.

关键词： copper aluminosilicate silicate flotation

Discrimination between demodex folliculorum(Acari:demodicidae) isolates from China and Spain based on mitochondrial cox1 sequences

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2013年第9期14卷 829-836页

作者： Ya-e ZHAO Jun-xian MA Li HU Li-ping WU Manuel de ROJAS department of Immunology and Pathogen Biology Xi'an Jiaotong University College of Medicine department of Microbiology and Parasitology Faculty of PharmacyUniversity of Sevilla

For a long time,classification of demodex mites has been based mainly on their hosts and phenotypic characteristics.A new subspecies of demodex folliculorum has been proposed,but not ***,cox1 partial sequences of nine isolates of three demodex species from two geographical sources(China and Spain) were studied to conduct molecular identification of *** showed that the mitochondrial cox1 fragments of five *** isolates from the facial skin of Chinese individuals were 429 bp long and that their sequence identity was 97.4%.The average sequence divergence was 1.24% among the five Chinese isolates,0.94% between the two geographical isolate groups(China(5) and Spain(1)),and 2.15% between the two facial tissue sources(facial skin(6) and eyelids(1)).The genetic distance and rate of third-position nucleotide transition/transversion were 0.0125,2.7(3/1) among the five Chinese isolates,0.0094,3.1(3/1) between the two geographical isolate groups,and 0.0217,4.4(3/1) between the two facial tissue *** trees showed that *** from the two geographical isolate groups did not form sister clades,while those from different facial tissue sources *** to the molecular characteristics,it appears that subspecies differentiation might not have occurred and that *** isolates from the two geographical sources are of the same ***,population differentiation might be occurring between isolates from facial skin and eyelids.

关键词： demodex folliculorum cox1 partial sequences Divergence Genetic relationship Phylogenetic tree

Numerical Modelling and experimental Investigation of Microse-gregation in Al-4.45 wt pct Cu:effect of dendrite Joining

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2005年第5期21卷 753-758页

作者： H.B.Dongdepartment of engineering, University of leicester, leicester, le1 7RH, UK department of engineering University of Leicester Leicester LE1 7RH United Kingdom

A numerical model Alloy/M has been applied to investigate the microsegregation in Al-4.45 wt pct Cu alloy. The calculated data were compared with the experimental measurements for samples solidified at different cooling rates. Discrepancies in solute concentration occur between the experimental observations and calculated results. Reasons for the discrepancies were discussed, and the effect of dendrite joining at a later stage of solidification on the microsegregation was investigated. Calculations that have included this effect showed a better fit with experimental results.

关键词： Microsegregation Numerical modelling dendrite growth Aluminium alloy dendrite joining

A New Fractional Model for the Falling Body Problem

在线全文

学校读者我要写书评

暂无评论

Chinese Physics letters 2017年第2期34卷 1-3页

作者： A.ebaid B.Masaedeh e.e1-Zahar department of Mathematics Faculty of ScienceTabuk UniversityP.O.Box 741Tabuk 71491Kingdom of Saudi Arabia department of Mathematics Faculty of Sciences and HumanitiesPrince Sattam Bin Abdulaziz UniversityA1kharj11942Kingdom of Saudi Arabia department of Basic engineering Science Faculty of EngineeringShebin El-Kom32511Menofia UniversityEgypt

Recently, a conformable fractional derivative has been proposed to calculate the derivative of non-integer order of time functions. It has been shown that this new fractional derivative definition obeys many advantages over the preceding definitions. For mathematical models in applied sciences and to preserve the dimensionality of the physical quantities, an auxiliary parameter （~r） which has the dimension of seconds should be implemented in the fractional derivative definition. We obtain analytic solutions for the resulting conformable fractional differential equations describing the vertical velocity and the height of the falling body. It is shown that the dimensions of velocity and height are always correct without any restrictions on the auxiliary parameter cr which contradicts with the results in the literature when applying the Caputo definition to the same problem. This may open the door for many future works either to describe the role of such an auxiliary parameter or to derive a more suitable definition for the fractional derivative.

关键词： A New Fractional Model for the Falling Body Problem

A TRUST-ReGION ALGORITHM FOR SOLVING MINI-MAX PROBleM

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2018年第6期36卷 776-791页

作者： Bothina e1-Sobky Abdallah Abotahoun department of Mathematics Alexandria University Alexandria Egypt

In this paper, we propose an algorithm for solving inequality constrained mini-max optimization problem. In this algorithm, an active set strategy is used together with mul- tiplier method to convert the inequality constrained mini-max optimization problem into unconstrained optimization problem. A trust-region method is a well-accepted technique in constrained optimization to assure global convergence and is more robust when they deal with rounding errors. One of the advantages of trust-region method is that it does not require the objective function of the model to be convex. A global convergence analysis for the proposed algorithm is presented under some conditions. To show the efficiency of the algorithm numerical results for a number of test problems are reported.

关键词： Mini-max problem Active-set Multiplier method Trust-region Global con-vergence

Differentiation profile of brain tumor stem cells:a comparative study with neural stem cells

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

Cell Research 2006年第12期16卷 909-915页

作者： Quan Bin Zhang~1 Xiao Yan Ji~1 Qiang Huang~1 Jun Dong~1 Yu de Zhu~1 Qing Lan~1 Neurosurgical department and Brain Tumor Research Laboratory,Second Affiliated Hospital of Suzhou Universiry,Suzhou 215004,China Neurosurgical department and Brain Tumor Research Laboratory Second Affiliated Hospital of Suzhou University Suzhou China

Understanding of the differentiation profile of brain tumor stem cells (BTSCs),the key ones among tumor cell popula-tion,through comparison with neural stem cells(NSCs)would lend insight into the origin of glioma and ultimately yieldnew approaches to fight this intractable ***,we cultured and purified BTSCs from surgical glioma specimensand NSCs from human fetal brain tissue,and further analyzed their cellular biological behaviors,especially their differ-entiation *** expected,NSCs differentiated into mature neural phenotypes. In the same differentiation condition,however,BTSCs exhibited distinguished ***,cells grew flattened and attached for the first week,but gradually aggregated and reformed floating tumor sphere *** the corresponding period,the expressionrate of undifferentiated cell marker CD 133 and nestin in BTSCs kept decreasing,but 1 week later,they regained ascend-ing ***,the differentiated cell markers GFAP and β-tubulinⅢ showed an expression change inverse tothat of undifferentiated cell *** together,BTSCs were revealed to possess a capacity to resist differentiation,which actually represents the malignant behaviors ofglioma.

关键词： brain tumor stem cell neural stem cell differentiation

Impact of the association between elevated oestradiol and low testosterone levels on erectile dysfunction severity

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2013年第4期15卷 492-496,I0007-I0008页

作者： Ahmed I e1-Sakka department of Urology Suez Canal University 41111 Ismailia Egypt and AI-Noor Specialist Hospital Makkah PO Box 6251 Saudi Arabia

Our aim was to assess the impact of the association between elevated oestradiol （e2） and low testosterone （T） levels on erectile dysfunction （eD） severity. A total of 614 male patients with eD and a normal or low T level in association with normal or elevated e2 levels were enrolled. Patients underwent routine laboratory investigations in addition to measurements of total T, total e2, follicle-stimulating hormone （FSH）, luteinizing hormone （LH） and prolactin. We compared the responses to the erectile function domain, Q3 （achieving erection） and Q4 （maintaining erection） of the International Index for erectile Function （IIeF） score in patients with the following： normal T and e2 levels; low T level; low T level and elevated e2 level; and elevated e2 level. Of the patients included, 449 （73.1%） had normal T and e2 levels, 110 （17.9%） had a low T level, 36 （5.9%） had a low T level and an elevated e2 level, and 19 （3.1%） had an elevated e2 level. Increased eD severity was significantly associated with low T levels, elevated e2 levels, and both a low T level and an elevated e2 level. Additionally, the mean values of the eF-domain, Q3 and Q4 were significantly lower in patients with both a low T level and an elevated e2 level compared to patients with any condition alone. In conclusion, a low T level had the primary effect on erectile function; however, a concomitantly elevated e2 level had an additive impairment effect.

关键词： erectile dysfunction (eD) hypogonadism testosterone oestradiol

Lightweight Al-Nb-Ti-V-Cr high entropy alloys with high hardness and enhanced mechanical properties via doping Co

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

China Foundry 2025年

作者： Fang-dong Xu de-zhi Chen Rui-run Chen Bin Gan Jing-yue Yu National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of Technology Suzhou Laboratory

To develop high-hardness and high-strength lightweight high entropy alloys （LHeAs）,a series of CoxAlNbTiVCr alloys were *** phase constitution,distribution,and crystal structure of the Laves phase in alloys can be altered by adjusting the composition of HeAs,which in turn influences their mechanical *** Nb Ti VCr （x=0,0.5,1,1.5,and 2,atomic ratio percentage） LHeAs were designed and prepared to characterize the microstructure and tailor the mechanical *** introduction of Co changes the microstructure of LHeAs from a single B2 structure to a mixture dendrite structure,which consists of B2 phase,C14 and C15 Laves *** the C14 and C15 Laves phases exhibit coupled *** parameters including mixing enthalpy (ΔHmix),valence electron concentration （VeC）,atomic radius size （δ）,mixing entropy （ΔS）,and electronegativity difference （Δχ） are used to predict the formation of B2 and Laves phase in *** the Co content increases from 0 to 1.5at.%,Laves phase volume fraction gradually increases,which leads to an enhancement in the compressive strength from 1,520.8 MPa to 1,844.4 ***1.5Al Nb Ti VCr alloy exhibits the maximum Vickers hardness of 699.4 *** improvement of mechanical properties mainly originates from solid solution strengthening and second phase strengthening.

关键词：