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Numerical investigation into the effect of b.ckfilling on coal p.llar strength in highwall mining

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International Journal of Mining Science and Technology 2018年第2期28卷 281-286页

作者： Mo S. Canb.lat I. Zhang C. Oh J. Shen b. Hagan p. School of Mining Engineering The University of New South Wales CSIRO Energy QCAT1 Technology Court

This p.p.r attemp.s to quantify the effect of b.ckfilling on p.llar strength in highwall mining using numerical modelling. Calib.ation against the new emp.rical strength formula for highwall mining was conducted to ob.ain the material p.rameters used in the numerical modelling. With the ob.ained coal strength p.rameters, three sets of b.ckfill p.op.rties were investigated. The results reveal that the b.havior of p.llars varies with the typ. and amount of b.ckfill as well as the p.llar width to mining height ratio(w/h). In case of cohesive b.ckfill, generally 75% b.ckfill shows a significant increase in p.ak strength, and the increase in p.ak strength is more p.onounced for the p.llars having lower w/h ratios. In case of noncohesive b.ckfill, the changes in b.th the p.ak and residual strengths with up.to 92% b.ckfill are negligib.e while the residual strength constantly increases after reaching the p.ak strength only when 100%b.ckfill is p.aced. b.sed on the modelling results, different b.ckfilling strategies should b. considered on a case b. case b.sis dep.nding on the typ. of b.ckfill availab.e and desired p.llar dimension.

关键词： Highwall mining b.ckfill Coal p.llar Strength Numerical modelling

Effects of sonication amp.itude on the microstructure and mechanical p.op.rties of AZ91E magnesium alloy

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Journal of Magnesium and Alloys 2022年第12期10卷 3397-3405页

作者： p.Emadi b.Andilab.C.Ravindran Centre for Near-net-shap. p.ocessing of Materials Ryerson University350 Victoria StreetTorontoON M5B 2K3 Canada

Light metals are gaining increased attention due to ecological sustainab.lity concerns and strict emission regulations. Magnesium(Mg)is one such metal that has the p.tential to rep.ace high density comp.nents, which can reduce emissions through lightweighting. However,the mechanical p.op.rties of Mg alloys must b. imp.oved for them to b.come viab.e candidates for structural ap.lications. To this end, the current study examines the effect of sonication vib.ational amp.itude on the microstructure and mechanical p.op.rties of AZ91E Mg *** molten alloys were sub.ected to ultrasonic treatment at a frequency of 20 kHz, 180 s of p.ocessing time and vib.ational amp.itudes ranging from 1.25 to 15 μm. The resultant castings were characterized using op.ical microscop., scanning electron microscop. and tensile testing. It was found that sonication with amp.itudes up.to 7.5 μm was ab.e to effectively refine the secondary p.ases of the alloy. Similar trends were ob.erved for grain size and yield strength. The refinement in microstructure was likely caused b. the finer grain size and cavitation induced undercooling of the liquid metal. In addition, it was also noted that even the lowest level of amp.itude(1.25 μm) was ab.e to increase the density, imp.ove the ultimate tensile strength and ductility of the castings. The tensile strength and ductility were thought to have b.en enhanced b. ultrasonic degassing and refinement in microstructure, while the yield strength was imp.oved through the Hall-p.tch effect. The results from this study p.ovided a b.sis for op.imizing the sonication p.ocess and p.omoting its use in industry. As a result, Mg alloys imp.oved through ultrasonic p.ocessing have the p.tential to rep.ace higher density comp.nents, with consequent energy efficiency and environmental and ecological b.nefits.

关键词： Magnesium Casting and solidification Ultrasonic p.ocessing Vib.ational amp.itude Grain refinement Mechanical p.op.rties

Echocardiograp.ic p.edictors and associated outcomes of multip.e vegetations in infective endocarditis:A p.lot study

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World Journal of Cardiology 2024年第6期16卷 318-328页

作者： Ajay Kumar Mishra Kannu b.nsal Ib.agim Al-Seykal p.adnya b.b.attad Anu Anna George Anil Jha Nitish Sharma Jennifer Sargent Mark J Kranis Division of Cardiology Saint Vincent HospitalWorcesterMA 01608United States Dep.rtment of Internal Medicine Saint Vincent HospitalWorcesterMA 01608United States Dep.rtment of Medicine Division of CardiologySaint Vincent HospitalWorcesterMA 01608United States Division of Cardiovascular Medicine Saint Vincent HospitalWorcesterMA 01608United States

b.CKGROUND Infective endocarditis(IE)is a life-threatening infection with an annual mortality of 40%.Emb.lic events rep.rted in up.to 80%of *** of>10 mm size are associated with increased emb.lic events and p.or *** is a p.ucity of literature on the association of multip.e vegetations with *** To study the echocardiograp.ic(ECHO)features and outcomes associated with the p.esence of multip.e *** In this retrosp.ctive,single-center,cohort study p.tients diagnosed with IE were recruited from June 2017 to June 2019.A total of 84 p.tients were diagnosed to have IE,of whom 67 with vegetation were *** demograp.ic,clinical,lab.ratory,and ECHO p.rameters were *** that were studied included recurrent admission,emb.lic p.enomenon,and *** Twenty-three(34%)p.tients were noted to have multip.e vegetations,13(56.5%)were male and 10(43.5%)were *** mean age of these p.tients was ***(35%)had a p.ior ep.sode of *** features of moderate to severe valvular regurgitation[odds ratio(OR)=4],p.esence of p.cemaker lead(OR=4.8),imp.ired left ventricle(LV)relaxation(OR=4),and elevated p.lmonary artery systolic p.essure(p.Sp.(OR=2.2)are associated with higher odds of multip.e *** these moderate to severe valvular regurgitation(p.0.028),p.cemaker lead(p.0.039)and imp.ired relaxation(p.0.028)were statistically *** p.tients were noted to have an increased association of recurrent admissions(OR=3.6),recurrent b.cteremia(OR=2.4),emb.lic p.enomenon(OR=2.5),intensive care unit stay(OR=2.8),hyp.tension(OR=2.1),surgical intervention(OR=2.8)and device removal(OR=4.8).Of this device removal(p.0.039)and recurrent admissions(p.0.017)were statistically *** This study highlights the associations of ECHO p.edictors and outcomes in p.tients with IE having multip.e *** features of moderate to severe regurgitation,p.esence of p.cemaker lead,imp.i

关键词： Endocarditis Echocardiograp.y Vegetations p.edictors Outcome

Jatonik p.lyherb.l mixture induced rat liver MMp. p.re op.ning in normal Wistar rat:In vitro and in vivo studies

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Chinese Herb.l Medicines 2024年第1期16卷 113-120页

作者： Olab.nri p.Folashade Ib.ahim Damilare b.yenle Tolulop. A.Oyedeji Fiyinfoluwa Demilade Ojeniyi Adisa Ayob.mi Damilare Leonard O.Ehigie Adeola Folasade Ehigie Memb.ane b.ochemistry and b.op.ysics Research Lab.ratory Department of BiochemistryLadoke Akintola University of TechnologyOgbomoso 210214Nigeria Comp.tational b.ology/Drug Discovery Lab.ratory Department of BiochemistryLadoke Akintola University of TechnologyOgbomoso 210214Nigeria College of Health Sciences Crescent University AbeokutaAbeokuta 111105Nigeria Dep.rtment of b.ochemistry University of LagosLagos 101017Nigeria

Ob.ective:To assess acute toxicity,the in vitro and in vivo effects of methanol and ethyl acetate extracts(JME and JEE)of Jatonik p.lyherb.l mixture on some mitochondria-related p.rameters and their effect on the activity of some liver ***:Acute toxicity of JME and JEE was determined using Lorke’s *** vitro and in vivo op.ning of the mitochondrial memb.ane p.rmeab.lity transition p.re(MMp. p.re)was sp.ctrop.otometrically *** of malondialdehyde(MDA)as an index of lip.d p.roxidation and the activity of mitochondrial ATp.se was evaluated in vitro and in vivo and the effect of JME and JEE on the activity of liver enzymes such as alkaline p.osp.atase(ALp.,asp.rtate and alanine aminotransferase(AST and ALT)and gamma-glutamyl transferase(GGT)was also ***:JME had an LD_(50) of 3808 mg/kg b.w whereas JEE had an LD_(50) greater than 5000 mg/kg *** *** the rats have b.en fed with b.th extracts,a p.otomicrograp. of a p.ece of liver tissue showed no ap.arent symp.oms of *** the in vitro and in vivo studies,b.th extracts p.omp.ed intact mitochondria to op.n their MMp. *** comp.red to the control,lip.d p.roxide p.oduct release and ATp.se activity were significantly increased(p.0.05)in vitro and in *** activities of AST,ALT,and GGT were all reduced at 50 mg/kg when treated with JME,b.t the activity of AST was considerab.y enhanced when treated with JEE(p.0.05).The results revealed that b.th JME and JEE of the Jatonik p.lyherb.l mixture had low toxicity,p.ofound MMp.p.re induction,and enhanced ATp.se activity,b.t an increased MDA ***:Jatonik extracts may b. a p.omising target for drug develop.ent in diseases where there is dysregulation of ap.p.osis,however,further studies are needed to b.tter clarify the molecular mechanism involved in these p.enomena.

关键词： acute toxicity Ageratum conyzoides Linn. ap.p.osis Hunteria umb.llate(K.Schum.)Hallier f. Lep.dium meyenii Walp. mitochondrial ATp.se mitochondrial lip.d p.roxidation mitochondrial memb.ane p.rmeab.lity transition p.re p.lyherb.l mixture Xylop.a aethiop.ca(Dunal)A.Rich

From statistical analysis to p.ocess op.imization during cladding using a Nd:YAG laser

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China Welding 2022年第4期31卷 7-22页

作者：亚伟 p.thiraj b. 于兴华 University of Twente Faculty of Engineering TechnologyDepartment of Mechanics of SolidsSurfaces&Systems(MS3)EnschedeP.O.Box 2177500 AEThe Netherlands Materials innovation institute(M2i) DelftP.O.Box 50082600 GAThe Netherlands b.ijing Institute of Technology Chongqing Innovation Centre Chongqing 401120China School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China

Ap.lication of statistical methods to op.imize the p.ocess p.rameters was achieved b. emp.oying full factorial design of exp.riments,which was accomp.ished b. cladding using step.ise ramp.d laser *** correlations b.tween clad geometry and dilution(clad characteristics)and the main p.ocess p.rameters laser p.wer(p.(l)),cladding sp.ed(v_(c)),the p.wder feed rate(m)were ob.ained through ap.lication of variance analysis technique(ANOVA).The ob.ained correlations b.tween the main p.ocessing p.rameters and the clad characteristics are discussed and a statistical model was *** desirab.lity investigations using the develop.d statistical model were p.rformed b. considering the clad geometry,asp.ct ratio,dilution and *** p.rameters for cladding Stellite 6 on AISI 420 steel sub.trate and for cladding Nucalloy 488V on S355 J2 steel sub.trate were *** op.imal p.ocessing p.rameters can b. ap.lied to clad other materials with similar chemical comp.sitions.

关键词： laser cladding statistical model p.ocess op.imization clad geometry dilution p.wder efficiency

Theoretical Study of b.nzothiazole and Its Derivatives: Molecular Structure, Sp.ctroscop.c p.op.rties, Nb., MEp.and TD-DFT Analyses

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Journal of Materials Science and Chemical Engineering 2024年第3期12卷 31-50页

作者： Konaté Ab.oulaye b.dé Affoué Lucie Ouattara Lamoussa Koné Soleymane b.mb. Kafoumb. Lab.ratory of Constitution and Reaction of Matter University Félix Houphou&#235t-Boigny Abidjan Ivory Coast Dep.rtment of Marine Sciences University of San-Pedro San-Pedro Ivory Coast Lab.ratory of Thermodynamics and p.ysico-Chemistry of Environment University Nangui Abrogoua Abidjan Ivory Coast

b.nzothiazole (b.H) and its derivatives are organic molecules with b.ologic actions. b.cause of their many ap.lications, they are p.oduced on a massive scale and used in a numb.r of environmental comp.rtments. Their discharge into water p.oduces environmental p.ob.ems, exp.sing our environment to p.b.ic health p.ob.ems. A solution that can contrib.te to their deterioration is b.coming a necessity. For this reason, a concep.ual analysis of the reactivity of b.nzothiazole and four of its comp.unds was undertaken in order to investigate certain asp.cts of their b.odegradab.lity. A theoretical investigations of the comp.unds studied were conducted in the gas and water p.ases with the most widely used density functional theory method, b.cke-3-p.rameter-Lee-Yang-p.rr (b.LYp. with 6-31G+ (d, p. b.sis. Reactivity study calculated glob.l indices of reactivity revealed that 2-SCH3_b.H is the most reactive. Dip.le moment values analysis reveals that 2-NH2_b.H is the most solub.e in water, while the lip.p.ilicity shows that 2-NH2_b.H is the most hydrop.ilic comp.und. Thermodynamic p.rameters values reflect that reactions are resp.ctively exothermic and sp.ntaneous. b. analyzing an Electrostatic Molecular p.tential (EMp. map. researchers can p.np.int reactive sites on a molecule and anticip.te its reactivity. This assessment is further enhanced b. incorp.rating glob.l and local reactivity descrip.ors. Additionally, an exp.oration of frontier molecular orb.tals offers valuab.e insights into the molecule’s charge transfer characteristics. Moreover, a comb.ned examination of internal and external molecular interactions unveils hyp.rconjugative interactions arising from charge delocalization, as elucidated through natural b.nd orb.tal (Nb.) analysis.

关键词： b.nzothiazole Reactivity DFT/b.LYp Stab.lity TD-DFT

Scalar resonant frequencies and Hawking effect of an f(R) glob.l monop.le

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Chinese p.ysics C 2017年第9期41卷 138-145页

作者： H. S. Vieira J. p. Morals Graca V. b. b.zerra Institute of Cosmology Department of Physics and Astronomy Tufts University Medford Massachusetts 02155 USA Dep.rtamento de Fisica Universidade Federal da Parafba Caixa Postal 5008 CEP 58051-970 Joao Pessoa PB Brazil Instituto de Fisica Universidade Federal do Parana Curitiba PR Brazil

Massive scalar fields are considered in with a glob.l monop.le in f（R） gravity. The exact b.ckground is ob.ained and is given in terms of the Heun functions to study the Hawking radiation and the gravitational field p.oduced b. a Schwarzschild b.ack hole solution of the radial p.rt of the Klein-Gordon equation in this general Heun functions. We ap.ly the p.op.rties of the general the resonant frequencies of scalar p.rticles.

关键词： massive scalar field general Heun function b.ack hole radiation energy level

Significance of Transients in Soil Temp.rature Series

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p.dosp.ere 2007年第6期17卷 766-775页

作者： X. ZHOU N. p.RSAUD D. p. b.LESKY R. b. CLARK Dep.rtment of Crop.＆ Soil Sciences The Pennsylvania State University State College Pennsylvania 16802 （USA） Dep.rtment of Crop.＆ Soil Environmental Sciences Virginia Polytechnic Institute and State University Blacksburg Virginia 24061 （USA） USDA//ARS//AFSRC 1224 Airport Road Beaver West Virginia 25813 （USA）

The p.imary ob.ective of this study was to investigate the imp.ct of ob.ervation scale on the estimation of soil thermal *** are usually filtered out and ignored when classical Fourier ap.roaches are used to deconstruct and model temp.rature time *** was hyp.thesized that examination of such transients may b. more imp.rtant in identifying and quantifying short-term p.rturb.tions in internal soil heat transfer induced b. agronomic disturb.nces. Data-logged temp.ratures were collected at 10-minute intervals from thermistor p.ob.s installed at 10 and 25 cm dep.hs in isolated areas of two grassed *** p.ot(6T)had b.en treated twice with 6 Mg ha^(-1)comp.sted turkey litter as *** other p.ot(Np.)was fertilized at the same time with Np. *** methods were used to analyze the series to ob.ain ap.arent soil thermal diffusivity(D-value)at various time *** sup.orted the hyp.thesis that short-term differences in internal soil heat transfer b.tween the 6T and Np. p.ots were more manifest and effectively cap.ured b. estimated D-values calculated from the monthly and daily p.rtial *** 6T p.ot had higher soil organic matter content than the Np. p.ot and had lower ap.arent soil thermal *** soil temp.rature amp.itudes, required to calculate the mean D-values from p.rtial series,were more effectively ob.ained using a temp.rature change rate *** more commonly used Fourier analysis tended to b. effective for this p.rp.se when the p.rtial series reasonab.y p.esented well-defined diurnal p.tterns of increasing and decreasing temp.ratures.

关键词：土壤温度变化傅立叶分析有机物质热扩散

On the Average Numb.r of Unitary Factors of Finite Ab.lian Group. (Ⅱ)

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Acta Mathematica Sinica,English Series 2000年第4期16卷 549-554页

作者： Wenguang Zhai Dep.rtment of Mathematics, Shandong Normal University. Jinan 250014. p. b. China Dep.rtment of Mathematics Shandong Normal University Jinan 250014 P. R. China

Let t（G） b. the numb.r of unitary factors of finite ab.lian group.G. In this p.p.r we p.ove T（x）=∑(G≤（）t（G） =main terms+O(x(（1+2k）/（3+4k）for any exp.nent p.ir （k, 1/2+2K）. which imp.oves on the exp.nen... 详细信息

Let t（G） b. the numb.r of unitary factors of finite ab.lian group.G. In this p.p.r we p.ove T（x）=∑b.(b.G≤（）t（G） =main terms+O(xp.(p.（1+2k）/（3+4k）for any exp.nent p.ir （k, 1/2+2K）. which imp.oves on the exp.nent 9/25 ob.ained b. Xiaodong Cao and the author.

关键词： Unitary factor Finite Ab.lian group Exp.nential sum Divisor p.ob.em