检索结果-南通市图书馆

Ferroelectricity Induced by Oxygen Vacancies in Rhombohedral ZrO_(2) Thin Films

Energy & Environmental materials 2024年第1期7卷 229-237页

作者： Veniero Lenzi José P.B.Silva Břetislav Šmíd Vladimir matoín cosmin.m.istrate Corneliu Ghica Judith L.macmanus-Driscoll Luís marques Physics Center of minho and Porto Universities(CF-Um-UP) University of MinhoCampus de Gualtar 4710-057Braga Portugal Laboratory of Physics for materials and Emergent Technologies LapMETUniversity of Minho4710-057Braga Portugal Department of Surface and Plasma Science Faculty of Mathematics and PhysicsCharles UniversityV Holešovičkách 218000Prague 8 Czech Republic National Institute of materials Physics 105 bis Atomistilor 077125Magurele Romania Department of materials Science and metallurgy 27 Charles Babbage Rd.Cambridge CB3 OFSUK

Rhombohedral phase Hf_(x)Zr_(1.x)O_(2)(HZO,x from 0 to 1)films are promising for achieving robust ferroelectric polarization without the need for an initial wake-up pre-cycling,as is normally the case for the more commonly studied orthorhombic ***,a large spontaneous polarization observed in rhombohedral films is not fully understood,and there are also large discrepancies between experimental and theoretical *** this work,in rhombohedral ZrO_(2)thin films,we show that oxygen vacancies are not only a key factor for stabilizing the phase,but they are also a source of ferroelectric polarization in the *** is shown experimentally through the investigation of the structural properties,chemical composition and the ferroelectric properties of the films before and after an annealing at moderate temperature(400℃)in an oxygen environment to reduce the V_(o)concentration *** experimental work is supported by density functional theory(DFT)calculations which show that the rhombohedral phase is the most stable one in highly oxygen defective ZrO_(2)*** DFT calculations also show that V_(o)contribute to the ferroelectric *** findings reveal the importance of V_(o)for stabilizing rhombohedral ZrO_(2)thin films with superior ferroelectric properties.

关键词： charged defects ferroelectric polarization rhombohedral phase stability zirconia

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

An in vitro demonstration of a passive,acoustic metamaterial as a temperature sensor with mK resolution for implantable applications

引用

microsystems & Nanoengineering 2024年第1期10卷 41-54页

作者： Lucrezia maini Vicente Genovés Roman Furrer Nikola Cesarovic Christofer Hierold cosmin Roman micro-and Nanosystems Department of Mechanical and Process EngineeringETH ZurichTannenstrasse 38092 ZurichSwitzerland. Translational Cardiovascular Technology Department of Health Science and TechnologyETH ZurichLeopold-Ruzicka-Weg 48093 ZurichSwitzerland. Transport at Nanoscale Interfaces Swiss Federal Laboratories for Materials Science and TechnologyEMPAÜberlandstrasse 1298600 DübendorfSwitzerland Department of Cardiothoracic and Vascular Surgery Deutsches Herzzentrum der Charite(DHZC)13353 BerlinGermany

Wireless medical sensors typically utilize electromagnetic coupling or ultrasound for energy transfer and sensor *** transfer and management is a complex aspect that often limits the applicability of implantable sensor *** this work,we report a new passive temperature sensing scheme based on an acoustic metamaterial made of silicon embedded in a polydimethylsiloxane *** to other approaches,this concept is implemented without additional electrical components in situ or the need for a customized receiving unit.A standard ultrasonic transducer is used for this demonstration to directly excite and collect the reflected *** metamaterial resonates at a frequency close to a typical medical value(5 mHz)and exhibits a high-quality *** the design features of the metamaterial with the high-temperature sensitivity of the polydimethylsiloxane matrix,we achieve a temperature resolution of 30 *** value is below the current standard resolution required in infrared thermometry for monitoring postoperative complications(0.1 K).We fabricated,simulated,in vitro tested,and compared three acoustic sensor designs in the 29-43℃(~302-316 K)temperature *** this concept,we demonstrate how our passive metamaterial sensor can open the way toward new zero-power smart medical implant concepts based on acoustic interrogation.

关键词： passive resolution utilize

来源：

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

An artificial neural network based deep collocation method for the solution of transient linear and nonlinear partial differential equations

引用

Frontiers of Structural and Civil Engineering 2024年第8期18卷 1296-1310页

作者： Abhishek mISHRA cosmin ANITESCU Pattabhi Ramaiah BUDARAPU Sundararajan NATARAJAN Pandu Rang VUNDAVILLI Timon RABCZUK School of mechanical Sciences Indian Institute of TechnologyBhubaneswar 752050India Institute of Structural mechanics Bauhaus University of WeimarWeimar 99423Germany Department of mechanical Engineering Indian Institute of Technology MadrasChennai 600036India

A combined deep machine learning(DmL)and collocation based approach to solve the partial differential equations using artificial neural networks is *** developed method is applied to solve problems governed by the Sine–Gordon equation(SGE),the scalar wave equation and *** methods are studied:one is a space-time formulation and the other is a semi-discrete method based on an implicit Runge–Kutta(RK)time *** methodology is implemented using the Tensorflow framework and it is tested on several numerical *** on the results,the relative normalized error was observed to be less than 5%in all cases.

关键词： collocation method artificial neural networks deep machine learning Sine-Gordon equation transient wave equation dynamic scalar and elasto-dynamic equation Runge-Kutta method

来源：

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

Effect of Extending Voluntary Waiting Period on Health of Holstein Friesian Dairy Cows

引用

Open Journal of Veterinary medicine 2024年第6期14卷 124-136页

作者： Găvan Constantin Șonea cosmin Research Department Agriculture Research and Development Station imnic Craiova Romania University of Agronomical Sciences and Veterinary medicine Bucharest Bucureti Romania

The aim of this of this experimental study to investigate the effect of 3 voluntary waiting periods (VWP) on health of dairy cows. A total of 100 lactations of 100 Holstein Friesian cows with high milk production (average 9.442 ± 620 kg) were randomly (based on the ear tags digits of cows) distributed to 1 to 3 experimental groups with VWP of 50 (VWPG50;n = 32), 100 (VWPG100;n = 34) or 150 days (VWPG150;n = 34). Observations relating to diseases of the cows were made by the farm veterinarian and research personnel. Were defined eight disease: puerperal fever, retained fetal membranes, displaced abomasum, metritis, clinical ketosis, clinical mastitis, ovarian cysts, and claw diseases. The experimental days (ED) were from 4 days in milk (DIm) to 100 days after the next calving. The experiment was managed at Dairy Research Farm ?imnic-Craiova January 2018 to December 2022. A clear set of clinical signs were used to define a case at the diseases without the need for laboratory confirmation. Values of Lactational incidence risk (LIR) median postpartum days at diagnosis and pairwise comparison of proportion between VWPs were calculated. LIR for puerperal fiver, retained fetal membranes, displaced abomasum, clinical ketosis, clinical mastitis, ovarian cysts and claw disease were 4;5;2;8;8;and 4% respectively. Numerically, cows with VWP of 100 and150 days had more disease cases compared with VWP of 50 days. The differences between experimental groups of cows regarding proportions of cows with disease cases were not statistically significant. Any of the eight disorders reported in this study was analyzed independently to other health problems. For all enrolled cows (n = 100) VWP was extended until 100 or 150 days postpartum with no effect on the lactational incidence risk for the eight disorders analyzed.

关键词： Voluntary Waiting Period Dairy Cow Health Lactation Disorders Lactation Incidence Risk for Cow Diseases

来源：

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

Postnatal Total Serum Protein Concentration Influences the Health and Growth Parameters of Preweaned Female Holstein Friesian Calves

引用

Journal of Agricultural Science and Technology(A) 2024年第1期14卷 19-30页

作者： Găvan Constantin Șonea cosmin Research Department Agriculture Research and Development StationȘimnicCraiovaDolj 200721Romania University of Agronomical Sciences and Veterinary medicine of Bucharest Bucharest 011464Romania

This study focuses on the effect of the total serum protein(TSP)concentrations at 3 days after birth on the health and growth parameters of preweaned female Holstein Friesian calves.A total of 165 female calves were enrolled and evaluated for morbidity which included diarrhea(D),respiratory disease(Rd)and omphalitis(O).Also,calves with more than one disorder in the same time were recorded as *** weight(BW)was determined at birth,30 and 60 days of *** samples were taken at 3 days after birth and TSP was determined using a digital Brix *** statistical analysis all female calves based on TSP concentration were grouped into 3 categories:1-TSP≥6.2 g/dL,2-TSP 5.8-6.1 g/dL,and 3-TSPmphalitis(O)was 16.96%,7.88%and 4.85%respectively,in calves with one disorder and 6.06%in calves with D+Rd,3.64%in calves with Rd+O,3.03%in calves with O+D,and 3.64%in calves with D+Rd+*** the TSP concentration in calves decreased from≥6.2 g/dL tomale calves with one disorder and with more than one *** female calves with fair to poor immunity(category 3-TSPmore likely(OR 6.28,95%CI 2.91-13.5,p valuempared with female calves with excellent immunity(category 1-TSP≥6.2 g/dL).Also BW and average daily gain(ADG)at 30 and 62 days of life decreased as TSP concentrations *** female calves with TSP≥6.2 g/dL at 3 days of life had the greatest BW at 30 and 62 days of age(51.8 kg and 77.1 kg respectively)compared with female calves with TSPmoreover,starter feed intake during the first 30 days of life,31 to 62 days of life and 1 to 62 days of life was greater in female calves with excellent immunity(TSP≥6.2 g/dL)than female calves with good immunity(TSP 5.8-6.1 g/dL)o

关键词： Immunity categories diarrheal disease respiratory disease omphalitis disease multiple morbidity calf starter feed

来源：

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

Highly efficient fiber to Si waveguide free-form coupler for foundry-scale silicon photonics

引用

Photonics Research 2024年第5期12卷 1055-1066页

作者： LUIGI RANNO JIA Xu BRIAN SIA cosmin POPESCU DREW WENINGER SAmUEL SERNA SHAOLIANG YU LIONEL C.KImERLING ANURADHA AGARWAL TIAN GU JUEJUN HU Department of materials Science&Engineering Massachusetts Institute of TechnologyCambridgeMassachusetts 02139USA Centre for micro-&Nano-Electronics(CmNE) Nanyang Technological UniversitySingapore 639798Singapore Department of Physics Photonics and Optical EngineeringBridgewater State UniversityBridgewaterMassachusetts 02324USA Zhejiang Laboratory Hangzhou 311100China materials Research Laboratory Massachusetts Institute of TechnologyCambridgeMassachusetts 02139USA

As silicon photonics transitions from research to commercial deployment,packaging solutions that efficiently couple light into highly compact and functional sub-micrometer silicon waveguides are imperative but remain *** 220 nm silicon-on-insulator(SOI)platform,poised to enable large-scale integration,is the most widely adopted by foundries,resulting in established fabrication processes and extensive photonic component *** development of a highly efficient,scalable,and broadband coupling scheme for this platform is therefore of paramount *** two-photon polymerization(TPP)and a deterministic free-form micro-optics design methodology based on the Fermat’s principle,this work demonstrates an ultraefficient and broadband 3-D coupler interface between standard SmF-28 single-mode fibers and silicon waveguides on the 220 nm SOI *** coupler achieves a low coupling loss of 0.8 dB for the fundamental TE mode,along with 1 dB bandwidth exceeding 180 *** broadband operation enables diverse bandwidthdriven applications ranging from communications to ***,the 3-D free-form coupler also enables large tolerance to fiber misalignments and manufacturing variability,thereby relaxing packaging requirements toward cost reduction capitalizing on standard electronic packaging process flows.

关键词： fiber waveguide enable

来源：

维普期刊数据库

同方期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Frequency-dependent viscoelasticity effects on the wave attenuation performance of multi-layered periodic foundations

引用

Applied mathematics and mechanics(English Edition) 2024年第3期45卷 407-424页

作者： m.SAFI m.VAKILIFARD m.J.mAHmOODI Faculty of Civil Water&Environmental EngineeringShahid Beheshti UniversityTehran ***Iran Faculty of mechanical and Energy Engineering Shahid Beheshti UniversityTehran ***Iran

In this paper,layered periodic foundations(LPFs)are numerically examined for their responses to longitudinal and transverse modes in the time and frequency *** different unit-cells,i.e.,2-layer,4-layer,and 6-layer unit-cells,comprising concrete/rubber,concrete/rubber/steel/rubber,and concrete/rubber/steel/rubber/lead/rubber materials,respectively,are taken into ***,the viscoelasticity behavior of the rubber is modeled with two factors,i.e.,a frequency-independent(FI)loss factor and a linear frequency-dependent(FD)loss *** the extraction of the complex dispersion curves and the identification of the band gaps(BGs),the simulations of wave transmission in the time and frequency domains are performed using the COmSOL *** parametric studies evaluate the effects of the rubber viscoelasticity models on the dispersion curves and the wave transmission for the longitudinal and transverse *** results show that considering the rubber viscoelasticity enhances the wave attenuation ***,the transverse-mode damping is more sensitive to the viscoelasticity model than its longitudinal *** 6-layer unit-cell LPF exhibits the lowest BG,ranging from 4.8 Hz to 6.5 Hz.

关键词： layered metamaterial periodic foundation complex dispersion curve wave transmission diagram

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Engineering of efficient visible light photocatalysts:Ti_(1-x+y)Cu_(x)La_(y)O_(2)(x=0.03;y=0,0.005,0.01) compositions

引用

Journal of Rare Earths 2024年第3期42卷 497-505,I0003页

作者： S.m.Yakout A.m.Youssef Inorganic Chemistry Department National Research Centre(NRC)El Buhouth StDokkiCairo12622Egypt

In dye-photocatalysis, widening the wavelengths absorption range of catalysts as well as aborting the recombination of the photoexcited charge carriers(electrons-holes pairs) are of paramount *** the current study, we report the photocatalytic characteristics of four compositions composed of TiO_(2),Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders for two harmful dyes(Congo red and methylene blue). The X-ray diffraction technique verified the configuration of mixed anatase and rutile phases in pure TiO_(2)and Ti_(0.97)Cu_(0.03)O_(2)powders while Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders possess anatase phase only. The changes of the band gap structure and dimensions of the unit cell volume of TiO_(2)confirm the substitution of Ti^(4+)sites by Cu^(2+)and La^(3+)ions. Remarkable widening of wavelengths absorption with formation of long absorption tails were found in TiO_(2)(3.13 e V) through insertion of La^(3+)plus Cu^(2+)ions. Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)samples exhibit a visible light band gap of 2.3 and 2.7 e V, respectively. Based on SEm images, incorporation of Cu^(2+)and La^(3+)ions influences the surface morphology of TiO_(2). The resulting Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders present enhanced photocatalytic activity towards Congo red dye degradation compared to pure one under natural solar spectrum. The best Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)catalyst exhibits superior photocatalytic activity of 96% for 10 ppm CR dye in 20 min as well as above average photocatalytic efficiency of 63% for 30 ppm CR dye in 120 min. As well, it showed acceptable photodegradation activity of 52% for 30 ppm mB solution in 140 min of sunlight irradiation. The heightened photodegradation efficiency of Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)catalyst can be clarified in terms of higher ch

关键词： Semiconductor TiO_(2) Rare earths Congo red methylene blue Solar spectrum Photodegradation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Nonlinear dynamic modeling of planar moving Timoshenko beam considering non-rigid non-elastic axial effects

引用

Applied mathematics and mechanics(English Edition) 2024年第3期45卷 479-496页

作者： m.ABBASI GAVARI m.R.HOmAEINEZHAD Faculty of mechanical Engineering K.N.Toosi University of TechnologyTehran 19991-43344Iran

Due to the importance of vibration effects on the functional accuracy of mechanical systems,this research aims to develop a precise model of a nonlinearly vibrating single-link mobile flexible *** manipulator consists of an elastic arm,a rotary motor,and a rigid carrier,and undergoes general in-plane rigid body motion along with elastic transverse *** accurately model the elastic behavior,Timoshenko’s beam theory is used to describe the flexible arm,which accounts for rotary inertia and shear deformation *** applying Newton’s second law,the nonlinear governing equations of motion for the manipulator are derived as a coupled system of ordinary differential equations(ODEs)and partial differential equations(PDEs).Then,the assumed mode method(Amm)is used to solve this nonlinear system of governing equations with appropriate shape *** assumed modes can be obtained after solving the characteristic equation of a Timoshenko beam with clamped boundary conditions at one end and an attached mass/inertia at the *** addition,the effect of the transverse vibration of the inextensible arm on its axial behavior is *** the axial rigidity,the effect makes the rigid body dynamics invalid for the axial behavior of the ***,numerical simulations are conducted to evaluate the performance of the developed model,and the results are compared with those obtained by the finite element *** comparison confirms the validity of the proposed dynamic model for the *** to the mentioned features,this model can be reliable for investigating the system’s vibrational behavior and implementing vibration control algorithms.

关键词： planar moving Timoshenko beam non-rigid non-elastic axial effect as-sumed mode method(Amm) nonlinear motion analysis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Free vibration and buckling analysis of polymeric composite beams reinforced by functionally graded bamboo fbers

引用

Applied mathematics and mechanics(English Edition) 2024年第3期45卷 543-562页

作者： H.m.FEIZABAD m.H.YAS Department of mechanical Engineering Razi UniversityKermanshah ***Iran

Natural fibers have been extensively researched as reinforcement materials in polymers on account of their environmental and economic advantages in comparison with synthetic fibers in the recent *** fibers are renowned for their good mechanical properties,abundance,and short cycle *** beams are one of the fundamental structural components and are susceptible to mechanical loads in engineering applications,this paper performs a study on the free vibration and buckling responses of bamboo fiber reinforced composite(BFRC)beams on the elastic *** different functionally graded(FG)layouts and a uniform one are the considered distributions for unidirectional long bamboo fibers across the *** elastic properties of the composite are determined with the law of *** Hamilton’s principle,the governing equations of motion are *** generalized differential quadrature method(GDQm)is then applied to the equations to obtain the *** achieved outcomes exhibit that the natural frequency and buckling load values vary as the fiber volume fractions and distributions,elastic foundation stiffness values,and boundary conditions(BCs)and slenderness ratio of the beam ***,a comparative study is conducted between the derived analysis outcomes for BFRC and homogenous polymer beams to examine the effectiveness of bamboo fibers as reinforcement materials,demonstrating the significant enhancements in both vibration and buckling responses,with the exception of natural frequencies for cantilever beams on the Pasternak foundation with the FG-◇fiber ***,the obtained analysis results of BFRC beams are also compared with those for carbon nanotube reinforced composite(CNTRC)beams found in the literature,indicating that the buckling loads and natural frequencies of BFRC beams are lower than those of CNTRC beams.

关键词： bamboo fiber free vibration buckling analysis functionally graded(FG)beam elastic foundation generalized differential quadrature method(GDQm)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：