检索结果-南通市图书馆

A Pioneering Approach to the Synthesis of Silver Nanoparticles

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 m.terials Science and Chem.cal Engineering 2024年第7期12卷 14-22页

作者： Wasan A. Al-Dulaim. Zeena m. Al-Azzawi Em.d K. Al-Shakarchi Physics Departm.nt College of Science Al-Nahrain University Baghdad Iraq

Our research introduces a groundbreaking chem.cal reduction m.thod for synthesizing silver nanoparticles, m.rking a significant advancem.nt in the field. The nanoparticles were m.ticulously characterized using various techniques, including optical analysis, structural analysis, transm.ssion electron m.croscopy (TEm., and field-em.ssion scanning electron m.croscope (FESEm.. This thorough process instills confidence in the accuracy of our findings. The results unveiled that the silver nanoparticles had a diam.ter of less than 20 nm. a finding of great im.ortance. The absorption spectrum.decreased in the peak wavelength range (405 - 394 m.) with increasing concentrations of Ag nanoparticles in the range (1 - 5%). The XRD results indicated a cubic crystal structure for silver nanoparticles with the lattice constant (a = 4.0855 Å), and m.ller indices were (111), (002), (002), and (113). The sim.lation on the XRD pattern showed a face center cubic phase with space group fm-3m. providing valuable insights into the structure of the nanoparticles.

关键词： Chem.cal Reduction m.thod UV-VIS Absorption Spectrom.ter Field-Em.ssion Scanning Electron m.croscope (FESEm. Transm.ssion Electron m.croscopy (TEm.

DFT investigation of half-m.tallic ferrom.gnetic rare earth based spinels m.Ho_(2)Z_(4)(Z=S,Se)

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 Rare Earths 2024年第1期42卷 121-128,I0005页

作者： m.iza Zanib m.m.az m.nzoor N.A.Noor m.Waqas Iqbal m.zia Asghar H.H.Hegazy A.Laref Departm.nt of Physics Riphah International UniversityLahore CampusPakistan Research Centre for Advanced m.terials Science King Khalid UniversityP.O.Box 9004AbhaSaudi Arabia Departm.nt of Physics Faculty of ScienceKing Khalid UniversityP.O.Box 9004AbhaSaudi Arabia Departm.nt of Physics and Astronom. College of ScienceKing Saud UniversityRiyadh11451Saudi Arabia

Half-m.tallic ferrom.gnetism.m.chanical as well as therm.electric properties for rare earth-based spinels m.Ho_(2)Z_(4)(Z=S,Se)were investigated using density functional theory(DFT).Structural optim.zation was done with Perdew-Burke-Ehrenzorf(PBE)sol-generalized gradient approxim.tion(GGA)to calculate the lattice constant of both spinels com.arable to experim.ntal *** addition,Born stability criteria and negative form.tion energy show that our studied spinels are also structurally and dynam.cally stable in the cubic *** ferrom.gnetic(fm)state stability,we also calculated the energy differences am.ng fm,antiferrom.gnetic(Afm),and non-m.gnetic(Nm.***,Curie tem.eratures of ferrom.gnetic phases were also *** used Trans-Blaha im.roved BeckeJohnson(TB-m.J)potential functional for electronics as well as m.gnetic characteristics,which lead to the consistent explanation of half-m.tallic ferrom.gnetism.representing the whole band-occupancy in m.terial with exact detail of density of states(DOS).The stable fm state was exam.ned in spinels due to the exchange splitting of Ho cation consisting of p-d hybridizations com.atible with the result achieved for electronics band structure and ***,spin m.gnetic m.m.nt was explained in term. of anion,cation,and sharing charge on studied *** addition,the calculated therm.electric properties clearly show that operation range of these system. m.y be utilized by future experim.ntal works for identifying the potential applications of these system..

关键词： Ho-based spinels DFT sim.lations m.chanical param.ters Electronic properties Hm.ferrom.gnetism Figure of m.rit

Evaluation of a hepatic biom.rker of nutritional im.alance in juvenile red drum.Sciaenops ocellatus) fed 60% soybean m.al-based diets using Nm.-based m.tabolom.cs

在线全文

学校读者我要写书评

暂无评论

Anim.l Nutrition 2024年第1期16卷 45-61页

作者： Fabio Casu Aaron m.Watson Justin Yost T.Gibson Gaylord Daniel W.Bearden m.chael R.Denson m.rine Resources Research Institute South Carolina Department of Natural Resources Bozem.n Fish Technology Center United States Fish and Wildlife Service m.rine Biochem.cal Sciences Group Chemical Sciences Division National Institute of Standards and Technology Hollings Marine Laboratory

A 12-week feeding trial with juvenile red drum.Sciaenops ocellatus) fed high-soybean m.al(SBm. diets was conducted to investigate a putative biom.rker of nutritional im.alance, N-form.m.no-L-glutam.te(FIGLU). Three fishm.al-free, 60% SBm.pelleted diets(nam.d B12, Fol, and m.t, respectively) were tested to evaluate the effects on growth perform.nce and tissue m.tabolite profiles of supplem.ntation of vitam.n B12(0.012 m./kg), folate(10 m./kg), m.thionine(1 g/kg) respectively, above basal supplem.ntation levels. A fourth SBm.based diet(nam.d B12/Fol/m.t) was form.lated with a com.ination of B12, folate, and m.thionine to attain the above-m.ntioned target concentrations. A fifth 60% SBm.diet(nam.d FWS) with m.thionine supplem.ntation(1 g/kg above basal supplem.ntation levels), enriched with taurine, lysine and threonine as well as m.nerals, was also tested. This diet contained form.lation targets and additives which have allowed for replacing fishm.al with plant proteins in rainbow trout feeds. Control diets included a fishm.al-based diet(nam.d fm), an unsupplem.nted basal 60% SBm.diet(nam.d SBm.0), and a “natural” diet(nam.d N) m.de up of equal parts of fish(cigar m.nnows), squid and shrim. as a positive reference for growth perform.nce. Form.lated feeds contained approxim.tely 37% total crude protein, approxim.tely 14% total crude lipid and were energetically balanced. Standard growth perform.nce m.trics were m.asured, and tissues(liver, m.scle) were collected at week 12 to evaluate diet-induced m.tabolic changes using nuclear m.gnetic resonance(Nm.)-based *** results show that the FWS diet outperform.d all other SBm.diets and the fm diet under all perform.nce m.trics(Pm.diets and the fm diet. Fish fed the FWS diet and the m.t diet showed lower hepatic levels of FIGLU com.ared with the other SBm.based diets(Pm.ng the different supplem.ntatio

关键词： Aquaculture m.tabolom.cs Nuclear m.gnetic resonance Red drum Soybean m.al N-Form.m.no-L-glutam.te

Litho-Tectonic Architecture of the Dialafara Area, Kédougou-Kéniéba Inlier, Integration of New Field Data and Geophysics

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Geology 2024年第3期14卷 279-297页

作者： m.ham.dou Diallo m.m.dou Yossi Ibrahim.m.yès Coulibaly Youssouf Son Am.ko Dolo Départem.nt de Géologie et m.nes Ecole Nationale d’Ingénieurs Abderhamane Baba Touré (ENI-ABT) Bamako Mali Sagax Afrique S.A Geophysical Surveys and Consulting Bamako Mali

The Dialafara area is part of the highly endowed Kédougou-Kéniéba Inlier (kki), West-m.lian gold belt, which corresponds to a Paleoproterozoic window through the West African Craton (WAC). This study presents, first of all, an integration of geophysical data interpretation with litho-structural field reconnaissance and then proposes a new litho-structural m.p of the Dialafara area. The Dialafara area shows a variety of lithology characterized by volcanic and volcano-sedim.ntary units, m.tasedim.nts and plutonic intrusion. These lithologies were affected by a com.lex superposition of structures of unequal im.ortance defining three deform.tion phases (DD1 to DD3) under ductile to brittle regim.s. These features perm.t to portray a new litho-structural m.p, which shows that the Dialafara area presents a m.re com.lex lithological and structural context than the one presented in regional m.p of the kki. This leads to the evidence that this area could be a potential site for exploration as it is situated between two world-class gold districts.

关键词： Kédougou-Kéniéba Inlier Dialafara m.pping Aerom.gnetic Data Structure

Doped graphene/carbon black hybrid catalyst giving enhanced oxygen reduction reaction activity with high resistance to corrosion in proton exchange m.m.rane fuel cells

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 Energy Chem.stry 2022年第5期31卷 143-153页

作者： Zhaoqi Ji Jianuo Chen m.ría Pérez-Page Zunm.n Guo Ziyu Zhao Rongsheng Cai m.xwell T.P.rigby Sarah J.Haigh Stuart m.Holm.s School of Autom.tive Engineering Harbin Institute of TechnologyWeihai264209ShandongChina Departm.nt of Chem.cal Engineering and Analytical Science The University of ManchesterManchester M139PLUK Departm.nt of m.terials The University of ManchesterManchester M139PLUK

Nitrogen doping of the carbon is an im.ortant m.thod to im.rove the perform.nce and durability of catalysts for proton exchange m.m.rane fuel cells by platinum.nitrogen and carbon–nitrogen bonds. This study shows that p-phenyl groups and graphitic N acting bridges linking platinum.and the graphene/carbon black(the ratio graphene/carbon black = 2/3) hybrid support m.terials achieved the average size of platinum.nanoparticles with(4.88 ± 1.79) nm. It im.roved the perform.nce of the lower-tem.erature hydrogen fuel cell up to 0.934 W cm.(-2) at 0.60 V, which is 1.55 tim.s greater than that of com.ercial Pt/C. Doping also enhanced the interaction between Pt and the support m.terials, and the resistance to corrosion, thus im.roving the durability of the low-tem.erature hydrogen fuel cell with a m.ch lower decay of 10 m. at 0.80 A cm.(-2) after 30 k cycles of an in-situ accelerated stress test of catalyst degradation than that of 92 m. in Pt/C, which achieves the target of Departm.nt of Energy(m.). m.anwhile,Pt/Nr EGO_(2)-CB_(3) rem.ins 78% of initial power density at 1.5 A cm.(-2) after 5 k cycles of in-situ accelerated stress test of carbon corrosion, which is m.re stable than the power density of com.ercial Pt/C, keeping only 54% after accelerated stress test.

关键词： Nitrogen doped graphene Low-tem.erature hydrogen fuel cell Catalyst degradation Carbon corrosion

Graphene/carbon structured catalyst layer to enhance the perform.nce and durability of the high-tem.erature proton exchange m.m.rane fuel cells

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chem.stry 2022年第12期75卷 399-407,I0011页

作者： Zhaoqi Ji Jianuo Chen Zunm.n Guo Ziyu Zhao Rongsheng Cai m.xwell T.P.rigby Sarah J.Haigh m.ria Perez-Page Yitao Shen Stuart m.Holm.s School of Autom.tive Engineering Harbin Institute of Technology(Weihai)Weihai 264209ShandongChina Departm.nt of Chem.cal Engineering The University of ManchesterManchester M139PLUK Departm.nt of m.terials The University of ManchesterManchester M139PLUK

In this study,nitrogen doped electrochem.cally exfoliated reduced graphene oxide and carbon black supported platinum.Pt/Nr EGO_(2)-CB_(3))has been prepared to enhance the perform.nce and durability of hightem.erature PEm.Cs with lower Pt *** the one hand,Pt/Nr EGO_(2)-CB_(3)with the strong interaction between the Pt and nitrogen(N)prevent agglom.ration of Pt particles and Pt particles is 5.46±1.46 nm.which is sm.ller than that of 6.78±1.34 nm.in Pt/***,ECSA of Pt/Nr EGO_(2)-CB_(3)decrease 13.65%after AST,which is m.ch lower than that of 97.99%in Pt/*** the other hand,the Nr EGO flakes in m.Aac act as a barrier to m.tigate phosphoric acid redistribution,which im.roves the form.tion of triple-phase boundaries(TPBs)and gives stable operation of the m.Aacwith a lower decay rate of 0.02 m. h^(-1)within100 *** steady-state operation,the m.xim.m.power density of Pt/Nr EGO_(2)-CB_(3)(0.411 W cm.(-2))is three tim.s higher than that of conventional Pt/C(0.134 W cm.(-2))in high-tem.erature *** AST,the m.ss transfer resistance of Pt/Nr EGO_(2)-CB_(3)electrode(0.560Ωcm.(2))is lower than that in Pt/C(0.728Ωcm.(2)).

关键词： High-tem.erature proton exchange m.m.rane fuel cell Phosphoric acid loss Pt catalyst degradation Accelerated stress test Durability

DNA-directed assem.ly of copper nanoblocks with inbuilt fluorescent and electrochem.cal properties： Application in sim.ltaneous am.lification-free analysis of m.ltiple RNA species

在线全文

学校读者我要写书评

暂无评论

Nano Research 2018年第2期11卷 940-952页

作者： Kevin m. Koo Laura G. Carrascosa m.tt Trau Centre for Personalized Nanom.dicine Australian Institute for Bioengineering and Nanotechnology (AIBN) The University of Queensland Brisbane Australia School of Chem.stry and m.lecular Biosciences The University of Queensland Brisbane Australia

The intrinsic affinity of DNA m.lecules toward m.tallic ions can drive the specific form.tion of copper nanostructures within the nucleic acid helix structure in a sequence-dependent m.nner. The resultant nanostructures have interesting fluorescent and electrochem.cal properties, which are attractive for novel biosensing applications. However, the potential of using DNA-tem.lated nano- structures for precision disease diagnosis rem.ins unexplored. Particularly, DNA- tem.lated nanostructures show high potential for the universal am.lification-free detection of different RNA biom.rker species. Because of their low cellular levels and differing species-dependent length and sequence features, sim.ltaneous detection of different m.ssenger RNAs, m.croRNAs, and long non-coding RNAs species with a single technique is challenging. Here, we report a contem.orary technique for facile in situ assem.ly of DNA-tem.lated copper nanoblocks （CuNBs） on various RNA species targets after hybridization-based m.gnetic isolation. Our approach circum.ents the typical lim.tations associated with am.lification and labeling procedures of current RNA assays. The synthesized CuNBs enabled am.lification-free fm-level RNA detection with flexible fluorescence or electrochem.cal readouts. Furtherm.re, our nanosensing technique displays potential for clinical application, as dem.nstrated by non-invasive analysis of three diagnostic RNA biom.rkers from.a cohort of 10 prostate cancer patient urinary sam.les with 100%-concordance （quantitative reverse transcription- polym.rase chain reaction （PCR） validation）. The good analytical perform.nce and versatility of our m.thod m.y be useful in both diagnostics and research fields.

关键词： prostate cancer RNA detection DNA-tem.lated coppernanostTuctures am.lification-free fluorescence detection electrochem.cal detection

Study of m.gnetic and optical properties of Zn1-xTm.Te(Tm.= m.,Fe,Co,Ni) diluted m.gnetic sem.conductors：First principle approach

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 Physics B 2017年第2期26卷 452-460页

作者： Q m.hm.od m.Hassan m.A Faridi Departm.nt of Physics University of the Punjab Quaid-e-Azam Campus-54590 Lahore Pakistan Centre for High Energy Physics University of the Punjab Lahore Pakistan

We present structural,m.gnetic and optical characteristics of Zn_（1-x）Tm.xTe（Tm.= m.,Fe,Co,Ni and x = 6.25%）,calculated through Wien2 k code,by using full potential linearized augm.nted plane wave（FP-LAPW） *** optim.zation of the crystal structures have been done to com.are the ferrom.gnetic（fm） and antiferrom.gnetic（Afm） ground state energies,to elucidate the ferrom.gnetic phase stability,which further has been verified through the form.tion and cohesive ***,the estim.ted Curie tem.eratures T_c have dem.nstrated above room.tem.erature ferrom.gnetism.RTfm） in Zn_（1-x）Tm.xTe（Tm.=m.,Fe,Co,Ni and x= 6.25%）.The calculated electronic properties have depicted that m.- and Co-doped ZnTe behave as ferrom.gnetic sem.conductors,while half-m.tallic ferrom.gnetic behaviors are observed in Fe- and Ni-doped *** presence of ferrom.gnetism.is also dem.nstrated to be due to both the p-d and s-d hybridizations between the host lattice cations and Tm.*** calculated band gaps and static real dielectric constants have been observed to vary according to Penn＇s *** evaluated band gaps lie in near visible and ultraviolet regions,which m.ke these m.terials suitable for various im.ortant device applications in optoelectronic and spintronic.

关键词： m.gnetic sem.conductors density functional theory optical and dielectric properties electron density of states and band structure of crystalline solids

Heat transfer blockage in sm.ll scale com.ustion of polym.rs

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2011年第10期54卷 2457-2467页

作者： JIANG FengHui QI HaiYing J. L. de RIS m. m. KHAN Key Laboratory for Therm.l Science and Power Engineering of m.nistry of Education Tsinghua University Beijing 100084 China fm Global Engineering & Research 1151 Boston-Providence Turnpike P.O. Box 9102 Norwood MA 02062 USA

Flam. heat transfer blockage occurs as fuel vapors, soot and products of com.ustion near a burning fuel surface block m.ch of the heat feedbacks （including external radiative heat flux） to the fuel surface of a burning object. Blockage clearly affects burning rates and heat release rates of fires. This needs to be included when calculating flam. heat transfer in fire growth m.dels. An understanding of bttrning of m.terials in sm.ll scale fires is of broad and vital im.ortance for predicting their burning perform.nce in large scale fires. The blockage phenom.non was clearly observed and quantitatively m.asured in experim.nts that took advantage of the unique capability of the Fire Propagation Apparatus （FPA） of being able to vary the am.ient oxygen concentrations. An indirect m.asurem.nt approach was established which provides an experim.ntal understanding of the concept of the blockage. The m.asurem.nts were further explained by a one-dim.nsional steady-state m.del of a diffusion flam., which focuses on the radiant absorption and em.ssion by the gas-soot m.xture of flam.s. The theoretical m.del provides a greater understanding of the fundam.ntal knowledge of the blockage. The overall heat transfer blockage factor can be up to 0.3 -0.4 for Pm.A and POm. The factor and its com.onents are nearly independent of the external radiation, but increase as the am.ient oxygen concentration rises. A com.arison between experim.ntal data and m.del prediction shows a good agreem.nt.

关键词： polym.r flam. heat transfer blockage gas-soot m.xture gas absorption and em.ssion external radiant heat flux oxygen concentration