检索结果-南通市图书馆

Chinese Physics B 2024年第2期33卷 108-114页

作者： U.S.mahabaleshwar G.P.Vanitha L.m.Pérez Emad h.Aly I.Pop Department of Studies in mathematics Davangere UniversityShivagangothriDavangereIndia Departamento de f´ısica FACIUniversidad de Tarapac´aCasilla 7DAricaChile Department of mathematics Faculty of EducationAin Shams UniversityRoxyCairoEgypt Department of mathematics Babes-Bolyai University400084 Cluj-NapocaRomania

We report on the magnetohydrodynamic impact on the axisymmetric flow of Al_(2)O_(3)/Cu nanoparticles suspended in h_(2)O past a stretched/shrinked *** the use of partial differential equations and the corresponding thermophysical characteristics of nanoparticles,the physical flow process is *** resultant nonlinear system of partial differential equations is converted into a system of ordinary differential equations using the suitable similarity *** transformed differential equations are solved *** of the magnetic parameter,solid volume fraction and stretching/shrinking parameter on momentum and temperature distribution have been analyzed and interpreted *** skin friction and Nusselt number were also *** addition,existence of dual solution was deduced for the shrinking sheet and unique solution for the stretching ***,Al_(2)O_(3)/h_(2)O nanofluid flow has better thermal conductivity on comparing with Cu/h_(2)O ***,it was found that the first solutions of the stream are stable and physically realizable,whereas those of the second ones are unstable.

关键词： magnetohydrodynamic nanofluid stretching/shrinking sheet axisymmetric flow analytical solution suction/injection

Effect of radiative loss mechanisms on fIR thermometric parameters of Nd^(3+)-doped lithium tellurite glasses

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第7期42卷 1250-1257,I0002页

作者： C.Y.morassuti A.P.L Silva L.A.O.Nunes S.m.Lima L.h.C.Andrade Optical and Photothermal Spectroscopy Group(GEOf) Center for Studies in Natural Resources(CERNA)State University of Mato Grosso do Sul(UEMS)C.P.351DouradosMSBrazil Renato Archer Information Technology Center Dom Pedro I Highway(SP-65)Km 1436-Chácaras Campos dos AmaraisCampinasSPBrazil Institute of Physics of São Carlos University of São PauloSão CarlosSPBrazil

Nd^(3+)-doped tellurite glasses are promising materials for thermometers based on the fluorescence intensity ratio(fIR)***,at high Nd^(3+)concentrations,energy transfer(ET)processes such as optical reabsorption and cross-relaxation can affect the Nd^(3+)emission,which has been little explored in the ***,the present work investigated the use of Nd^(3+)-doped tellurite glass(samples doped with Nd^(3+)at 0.2 mol%,0.5 mol%,2.0 mol%,and 4.0 mol%)in fluorescence thermometers,in the temperature range from 299 to 371 *** results indicate a strong dependence of the fIR parameters on the Nd^(3+)concentration,due to changes in the emission band profiles caused by optical reabsorption of the Nd^(3+)emissions and cross-relaxation processes.A decrease of the relative sensitivity of the ratio^(4)f_(5/2)→^(4)I_(9/2)/^(4)f_(3/2)→^(4)I_(9/2)is observed for samples doped with higher amounts of Nd^(3+).The maximum relative sensitivity at 299 K is 3.00%/K,which is the highest value among the reported Nd^(3+)ions.

关键词： Nd^(3+)-doped tellurite glass fluorescence intensity ratio Optical thermometry Judd-Ofelt Rare earths

Comparative analysis of microstructure,mechanical,and corrosion properties of biodegradable mg-3Y alloy prepared by selective laser melting and spark plasma sintering

在线全文

学校读者我要写书评

暂无评论

Journal of magnesium and Alloys 2024年第4期12卷 1496-1510页

作者： P.minárik m.Zemková S.Šašek J.Dittrich m.Knapek f.Lukáˇc D.Koutný J.Jaroš R.Král faculty of mathematics and Physics Charles UniversityKe Karlovu 5Praha 12116Czech Republic Research Centre University ofŽilinaUniverzitná8215/1Žilina 01026Slovakia Institute of Plasma Physics of the Czech Academy of Sciences Za Slovankou 1782/318200 Praha 8Czech Republic Institute of machine and Industrial Design Brno University of TechnologyTechnická2896/2Brno 61669Czech Republic

This work explored possibilities of biodegradable magnesium alloy mg-3Y preparation by two modern powder metallurgy techniques–spark plasma sintering(SPS)and selective laser melting(SLm).The powder material was consolidated by both methods utilising optimised parameters,which led to very low porosity(∼0.3%)in the SLm material and unmeasurably low porosity in the SPS *** main aim of the study was the thorough microstructure characterisation and interrelation between the microstructure and the functional properties,such as mechanical strength,deformability,and corrosion *** materials showed comparable strength of∼110 mPa in tension and compression and relatively good deformability of∼9%and∼21%for the SLm and SPS materials,*** corrosion resistance of the SPS material in 0.1 m NaCl solution was superior to the SLm one and comparable to the conventional extruded *** digital image correlation during loading and the cross-section analysis of the corrosion layers revealed that the residual porosity and large strained grains have the dominant negative effect on the functional properties of the SLm *** the other hand,one of the primary outcomes of this study is that the SPS consolidation method is very effective in the preparation of the W3 biodegradable alloy,resulting in material with convenient mechanical and degradation properties that might find practical applications.

关键词： magnesium Yttrium Powder metallurgy microstructure mechanical strength Corrosion resistance

Ultrafast magneto-optical dynamics in nickel(111)single crystal studied by the integration of ultrafast reflectivity and polarimetry probes

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第3期33卷 65-69页

作者：匡皓余军潇陈洁 h.E.Elsayed-Ali 李润泽 Peter m.Rentzepis School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China Center for Transformative Science ShanghaiTech UniversityShanghai 201210China Center for Ultrafast Science and Technology Key Laboratory for Laser Plasmas (Ministry of Education)Collaborative Innovation Center of IFSA (CICIFSA)School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Department of Electrical and Computer Engineering Old Dominion UniversityNorfolkVirginia 23529USA Department of Electrical and Computer Engineering Texas A&M UniversityCollege StationTexas 77843USA

With the integration of ultrafast reflectivity and polarimetry probes,we observed carrier relaxation and spin dynamics induced by ultrafast laser excitation of Ni(111)single *** carrier relaxation time within the linear excitation range reveals that electron-phonon coupling and dissipation of photon energy into the bulk of the crystal take tens of *** the other hand,the observed spin dynamics indicate a longer time of about 120 *** further understand how the lattice degree of freedom is coupled with these dynamics may require the integration of an ultrafast diffraction probe.

关键词： ultrafast spin dynamics non-equilibrium dynamics multi-probe

Telomeric DNA breaks in human induced pluripotent stem cells trigger ATR-mediated arrest and telomerase-independent telomere damage repair

在线全文

学校读者我要写书评

暂无评论

Journal of molecular Cell Biology 2024年第3期16卷 46-60页

作者： Katrina N.Estep John W.Tobias Rafael J.fernandez Brinley m.Beveridge f.Brad Johnson Department of Pathology and Laboratory medicine University of PennsylvaniaPhiladelphiaPA 19104USA Quantiative Biosciences Merck&Co.Inc.West PointPA 19486USA Penn Genomic Analysis Core University of PennsylvaniaPhiladelphiaPA 19104USA

Although mechanisms of telomere protection are well-defined in differentiated cells,how stem cells sense and respond to telomere dysfunction,in particular telomeric double-strand breaks(DSBs),is poorly ***,we report the DNA damage signaling,cell cycle,and transcriptome changes in human induced pluripotent stem cells(iPSCs)in response to telomere-internal *** engineer human iPSCs with an inducible TRf1-fokI fusion protein to acutely induce DSBs at *** this model,we demonstrate that TRf1-fokI DSBs activate an ATR-dependent DNA damage response,which leads to p53-independent cell cycle arrest in *** CRISPR–Cas9 to cripple the catalytic domain of telomerase reverse transcriptase,we show that telomerase is largely dispensable for survival and lengthening of TRf1-fokI-cleaved telomeres,which instead are effectively repaired by robust homologous recombination(hR).In contrast to hR-based telomere maintenance in mouse embryonic stem cells,where hR causes ZSCAN4-dependent extension of telomeres beyond their initial lengths,hR-based repair of telomeric breaks is sufficient to maintain iPSC telomeres at a normal length,which is compatible with sustained survival of the cells over several days of TRf1-fokI *** findings suggest a previously unappreciated role for hR in telomere maintenance in telomerase-positive iPSCs and reveal distinct iPSC-specific responses to targeted telomeric DNA damage.

关键词： telomeres telomerase alternative lengthening of telomeres pluripotent stem cells DNA damage double-strand breaks

Trauma to the solid abdominal organs:The missed dark box of colonoscopy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2024年第7期30卷 624-630页

作者： mohamed h Emara Usama mazid yasmine A Elshaer mahmoud A Elkerdawy Dilaver farooq malik Aya m mahros Department of hepatology Gastroenterologyand Infectious DiseasesKafrelsheikh UniversityKafr-Elshikh 33516Egypt Department of medicine Alyousif HospitalAlkhobar 31952Saudi Arabia

Colonoscopy is an integral part of the lower bowel care and is generally considered a potentially safe diagnostic and therapeutic procedure performed as a daycare outpatient *** is associated with different complications that are not limited to adverse events related to the bowel preparation solutions used,the sedatives used,but to the procedure related as well including bleeding and *** to the extra-luminal abdominal organs during colonoscopy are uncommon,however,serious complications related to the procedure have been reported infrequently in the *** threatening injuries to the spleen,liver,pancreas,mesentery,and urinary bladder have been reported as early as in *** injuries should not be overlooked by clinicians and *** increasing abdominal pain,abdominal distension,and hemodynamic instability in absence of rectal bleeding should raise the possibility of severe organ *** and hepatic injury following colonoscopy are usually serious and may be life *** conservative management may help,yet they usually need interventional radiology or surgical *** pancreatitis following colonoscopy is usually mild and is mostly managed *** mechanism of abdominal organ injuries during colonoscopy is not fully understood,however many risk factors have been identified,which can be classified as-organ related,procedure related,and local abdominal *** colonoscopy and prior intra-abdominal adhesions are probably the most relevant risk factors for these *** lateral position,avoidance of looping and excessive force during the procedure would probably reduce the risk of such injuries.

关键词： Colonoscopy Pancreatitis Trauma Complications Adhesions

Phase composition,conductivity,and sensor properties of cerium-doped indium oxide

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano materials Science 2024年第2期6卷 193-200页

作者： m.I.Ikim G.N.Gerasimov V.f.Gromov O.J.Ilegbusi L.I.Trakhtenberg N.N.Semenov federal Research Center for Chemical Physics of RAS MoscowRussia University of Central florida OrlandoFLUSA moscow Institute of Physics and Technology(State University) DolgoprudnyMoscow RegionRussia Lomonosov moscow State University MoscowRussia

The hydrothermal synthesis of In_(2)O_(3)and CeO_(2)–In_(2)O_(3)is investigated as well as the properties of sensor layers based on these *** the synthesis of In_(2)O_(3),intermediate products In(Oh)_(3)and InOOh are formed,which are the precursors of stable cubic(c-In_(2)O_(3))and metastable rhombohedral(rh-In_(2)O_(3))phases,respectively.A transition from c-In_(2)O_(3)to rh-In_(2)O_(3)is observed with the addition of CeO_(2).The introduction of cerium into rh-In_(2)O_(3)results in a decrease in the sensor response to hydrogen,while it increases in composites based on c-In_(2)O_(3).The data on the sensor activity of the composites correlate with XPS results in which CeO_(2)causes a decrease in the concentrations of chemisorbed oxygen and oxygen vacancies in rh-In_(2)O_(3).The reverse situation is observed in composites based on c-In_(2)O_(3).Compared to In_(2)O_(3)and CeO_(2)–In_(2)O_(3)obtained by other methods,the synthesized composites demonstrate maximum response to h_(2)at low temperatures by 70–100℃,and have short response time(0.2–0.5 s),short recovery time(6–7 s),and long-term stability.A model is proposed for the dependence of sensitivity on the direction of electron transfer between In_(2)O_(3)and CeO_(2).

关键词： Cerium oxide Indium oxide Nanocomposite hydrothermal method Cubic phase Rhombohedral phase Sensor response Conductivity hydrogen Response/recovery time

Design of a Novel Exoskeleton with Passive magnetic Spring Self-locking and Spine Lateral Balancing

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2024年第1期21卷 236-255页

作者： Jhon f.Rodríguez-León Betsy D.m.Chaparro-Rico Daniele Cafolla francesco Lago Eduardo Castillo-Castañeda Giuseppe Carbone Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada Unidad Querétaro MecatronicaInstituto Politécnico NacionalCerro Blanco 14176090 Colinas del CimatarioQuerétaroMexico Department of mechanical Energy and Management EngineeringUniversity of CalabriaVia P.Bucci Cubo 46 C87036 RendeItaly faculty of Science and Engineering Department of Computer ScienceSwansea UniversitySwanseaUK CESTER University of Cluj-NapocaCluj-NapocaRomania

This paper proposes a new upper-limb exoskeleton to reduce worker physical *** proposed design is based on a novel PRRRP(P-Prismatic;R-Revolute)kinematic chain with 5 passive Degrees of freedom(Dof).Utilizing a magnetic spring,the proposed mechanism includes a specially designed locking mechanism that maintains any desired task *** proposed exoskeleton incorporates a balancing mechanism to alleviate discomfort and spinal torsional effects also helping in limb weight *** paper reports specific models and simulations to demonstrate the feasibility and effectiveness of the proposed *** experimental characterization is performed to validate the performance of the mechanism in terms of forces and physical strain during a specific application consisting of ceiling-surface drilling *** obtained results preliminarily validate the engineering feasibility and effectiveness of the proposed exoskeleton in the intended operation task thereby requiring the user to exert significantly less force than when not wearing it.

关键词： Assistive mechanism Exoskeleton Locking mechanism Bionic robot

Role of marine natural products in the development of antiviral agents against SARS‑CoV‑2:potential and prospects

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

marine Life Science & Technology 2024年第2期6卷 280-297页

作者： D.P.Nagahawatta N.m.Liyanage Thilina U.Jayawardena h.h.A.C.K.Jayawardhana Seong‑hun Jeong hyung‑Jun Kwon You‑Jin Jeon Department of marine Life Sciences Jeju National UniversityJeju 690-756Republic of Korea Department of Chemistry Biochemistry and PhysicsUniversitédu QuébecàTrois-RivièresTrois-RivièresQC G8Z 4M3Canada marine Science Institute Jeju National UniversityJeju 63333Republic of Korea functional Biomaterial Research Center Korea Research Institute of Bioscience and BiotechnologyJeongeup-siRepublic of Korea

A novel coronavirus,known as severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),has surfaced and caused global concern owing to its ***-CoV-2 is the causative agent of coronavirus disease 2019;however,it was only discovered at the end of the year and was considered a pandemic by the World health ***,the develop-ment of novel potent inhibitors against SARS-CoV-2 and future outbreaks is urgently *** naturally occurring bioactive substances have been studied in the clinical setting for diverse *** intricate infection and replication mechanism of SARS-CoV-2 offers diverse therapeutic drug targets for developing antiviral medicines by employing natural products that are safer than synthetic *** natural products(mNPs)have received increased attention in the development of novel drugs owing to their high diversity and ***,this review article investigates the infection and replication mechanisms,including the function of the SARS-CoV-2 genome and ***,we highlighted anti-SARS-CoV-2 therapeutic intervention efforts utilizing mNPs and predicted SARS-CoV-2 inhibitor design.

关键词： SARS-CoV-2 marine natural products Drug targets Inhibitors

A hybrid machine-learning model for solar irradiance forecasting

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 2024年第1期8卷 100-110页

作者： Ameera m.Almarzooqi maher maalouf Tarek h.m.El-fouly Vasileios E.Katzourakis mohamed S.El moursi Constantinos V.Chrysikopoulos Department of Industrial and Systems Engineering Khalifa UniversityAbu DhabiPO Box 127788UAE Electrical Engineering and Computer Science Department Khalifa University Abu DhabiUAE Department of Civil Infrastructure and Environmental Engineering Khalifa UniversityAbu DhabiPO Box 127788UAE School of Chemical and Environmental Engineering Technical University of CreteChaniaGreece

Nowcasting and forecasting solar irradiance are vital for the optimal prediction of grid-connected solar photovoltaic(PV)power *** plants face operational challenges and scheduling dispatch difficulties due to the fluctuating nature of their power *** the generation capacity within the electric grid increases,accurately predicting this output becomes increasingly essential,especially given the random and non-linear characteristics of solar irradiance under variable weather *** study presents a novel prediction method for solar irradiance,which is directly in correlation with PV power output,targeting both short-term and medium-term forecast *** proposed hybrid framework employs a fast trainable statistical learning technique based on the truncated-regularized kernel ridge regression *** proposed method excels in forecasting solar irradiance,especially during highly intermittent weather periods.A key strength of our model is the incorporation of multiple historical weather parameters as inputs to generate accurate predictions of future solar irradiance values in its scalable *** evaluated the performance of our model using data sets from both cloudy and sunny days in Seattle and medford,USA and compared it against three forecasting models:persistence,modified 24-hour persistence and least *** on three widely accepted statistical performance metrics(root mean squared error,mean absolute error and coefficient of determination),our hybrid model demonstrated superior predictive accuracy in varying weather conditions and forecast horizons.

关键词： solar power generation kernel ridge regression hybrid model forecasting