检索结果-南通市图书馆

Dirac-like cone-based electromagnetic zero-index metamaterials

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2021年第11期10卷 2048-2066页

作者： Yang Li c.t.chan Eric Mazur State Key Laboratory of Precision Measurement technology and Instrument Department of Precision InstrumentTsinghua UniversityBeijingChina Department of Physics Hong Kong University of Science and TechnologyKowloonHong KongChina John A.Paulson School of Engineering and Applied Sciences Harvard UniversityCambridgeMAUSA

Metamaterials with a Dirac-like cone dispersion at the center of the Brillouin zone behave like an isotropic and impedance-matched zero refractive index material at the Dirac-point *** metamaterials can be realized in the form of either bulk metamaterials with efficient coupling to free-space light or on-chip metamaterials that are efficiently coupled to integrated photonic *** materials enable the interactions of a spatially uniform electromagnetic mode with matter over a large area in arbitrary *** unique optical property paves the way for many applications,including arbitrarily shaped high-transmission waveguides,nonlinear enhancement,and phase mismatch-free nonlinear signal generation,and collective emission of many *** review summarizes the Dirac-like cone-based zero-index metamaterials’fundamental physics,design,experimental realizations,and potential applications.

关键词： index collective realization

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

非晶硅薄膜的镍诱导横向晶化工艺及其特性

Journal of Semiconductors 2001年第1期22卷 57-60页

作者：秦明 VincentM.c.poon 东南大学微电子中心南京210096 香港科技大学电子与电机工程系

报道了镍诱导非晶硅薄膜的晶化技术 ,探讨了镍诱导晶化机理 .详细调查了诱导晶化时间和温度对晶化速率的影响 ,并用 Raman、AFM和 tEM等测试了材料的特性 .实验结果发现用该方法可以获得较大晶粒的多晶 ;在晶化温度为 6 2 5℃左右时晶... 详细信息

报道了镍诱导非晶硅薄膜的晶化技术 ,探讨了镍诱导晶化机理 .详细调查了诱导晶化时间和温度对晶化速率的影响 ,并用 Raman、AFM和 tEM等测试了材料的特性 .实验结果发现用该方法可以获得较大晶粒的多晶 ;在晶化温度为 6 2 5℃左右时晶体横向晶化速率最高 .如要获得较长的晶体。

关键词：镍诱导非晶硅薄膜横向晶化工艺

Influences of residual stress and micro-deformation on microstructures and mechanical properties for ti-6.5Al-3.5Mo-1.5Zr-0.3Si alloy produced by laser powder bed fusion

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & technology 2021年第16期75卷 174-183页

作者： c.c.Zhang H.L.Wei t.t.Liu L.Y.Jiang t.Yang W.H.Liao National Joint Engineering Research center of Nc Forming technology and Equipment School of Mechanical EngineeringNanjing University of Science and TechnologyNanjing 210094China

Laser powder bed fusion(LPBF)yields unique advantages during the fabrication of titanium *** the present work,ti-6.5 Al-3.5 Mo-1.5 Zr-0.3 Si alloy specimens with excellent mechanical performances were fabricated by *** as-built specimens displayed relatively high strength and ductility under modest volume energy densities(VEDs),whereas they manifested high strength with low ductility under high *** investigate the key reason of this phenomenon,the specimens were designed with two VEDs ranges of 60 J/mm^(3) and 85 J/mm^(3).Special attention was paid to the influences of residual stress and micro-deformation on microstructures and mechanical properties for the first *** results indicated that the residual stresses and relative density of the 60 J/mm^(3) range specimens were higher than that of the 85 J/mm3 range *** multiplication and dislocation movement promoted by the residual stress were hindered by the initialα’phase grain boundary(prior-α’GB),leading to the formation ofα’metastable *** mean tensile strength and elongation of the 60 J/mm^(3) range specimens were 1248.1 MPa and 12.3%,respectively,whereas the corresponding values for the 85 J/mm^(3) range specimens were 1405.3 MPa,5.0%,*** deformation,the strength and ductility of the specimens were first improved by lamellar structures generated from prior-α’phases,and then effectively enhanced by the interaction between the{10–12}twins and ***,pores significantly reduced the ductility;hence,high VED specimens with large twins and numerous large pores increased the strength and reduce the ductility.

关键词： Laser powder bed fusion ti-6.5Al-3.5Mo-1.5Zr-0.3Si alloy Residual stress twin Mechanical properties

A correlation between pulse diagnosis of human body and health monitoring of structures

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2004年第1期3卷 117-125页

作者： c.c.chang Henry t.Y.Yang Department of civil Engineering Hong Kong University of Science and TechnologyHong Kong Department of Mechanical and Environmental EngineeringUniversity of California Department of Mechanical and Environmental Engineering University of California

the concept of health monitoring is a key aspect of the field of medicine that has been practiced for a long time. A commonly used diagnostic and health monitoring practice is pulse diagnosis, which can be traced back approximately five thousand years in the recorded history of china. With advances in the development of modern technology, the concept of health monitoring of a variety of engineering structures in several applications has begun to attract widespread attention. Of particular interest in this study is the health monitoring of civil structures. It seem natural, and even beneficial, that these two health-monitoring methods, one as applies to the human body and the other to civil structures, should be analyzed and compared. In this paper, the basic concepts and theories of the two monitoring methods are first discussed. Similarities are then summarized and commented upon. It is hoped that this correlation analysis may help provide structural engineers with some insights into the intrinsic concept of using pulse diagnosis in human health monitoring, which may of be some benefit in the development of modern structural health monitoring methods.

关键词： human health monitoring pulse diagnosis structural health monitoring vibration-based techniques local detection techniques

Pushover analysis of reinforced concrete frames considering shear failure at beam-column joints

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2013年第3期12卷 373-383页

作者： Y.c.Sung t.K.Lin c.c.Hsiao M.c.Lai Bridge Division Center for Research on Earthquake EngineeringTaipei University of Technology (NTUT) chiao tung University taipei University of technology (NtUt)

Since most current seismic capacity evaluations of reinforced concrete （Rc） frame structures are implemented by either static pushover analysis （PA） or dynamic time history analysis, with diverse settings of the plastic hinges （PHs） on such main structural components as columns, beams and walls, the complex behavior of shear failure at beam-column joints （BcJs） during major earthquakes is commonly neglected. this study proposes new nonlinear PA procedures that consider shear failure at BcJs and seek to assess the actual damage to Rc structures. Based on the specifications of FEMA-356, a simplified joint model composed of two nonlinear cross struts placed diagonally over the location of the plastic hinge is established, allowing a sophisticated PA to be performed. to verify the validity of this method, the analytical results for the capacity curves and the failure mechanism derived from three different full-size Rc frames are compared with the experimental measurements. By considering shear failure at BcJs, the proposed nonlinear analytical procedures can be used to estimate the structural behavior of Rc frames, including seismic capacity and the progressive failure sequence of joints, in a precise and effective manner.

关键词： Rc frame beam-column joint pushover analysis capacity curve plastic hinge performance-based seismic evaluation

Improvising the Self-Healing capabilities of concrete Using Different Pozzolanic Materials and crystalline Admixtures

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of technology(Materials Science) 2022年第3期37卷 429-439页

作者： A Ravitheja t chandra Sekhara Reddy c Sashidhar SVR Engineering college AyyalurNandyalKurnoolAndhra PradeshIndia civil Engineering G Pulla Reddy Engineering CollegeKurnoolAPIndia Jawaharlal Nehru technological University AnantapurIndia

to analyse the self-healing capacities in terms of mechanical performance of the pozzolanic materials,such as,fly ash,metakaolin and silica fume and crystalline ***-cracked concrete cubes with about 0.05 mm width were exposed to four different environmental conditions at different exposure times in order to determine the effect of temperature and water availability on the self-healing *** the exposure,the control and tested concrete cubes were evaluated for regained strength,void reduction,corrosion inhibition,damp proofing,relative impermeability and *** samples with SF10cA have better cementitious filling and low percentage of voids and water absorption.

关键词： crystalline admixtures pozzolanic materials self-healing

Evolution of systemic therapy of advanced hepatocellular carcinoma

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2008年第42期14卷 6437-6441页

作者： thomas Yau Pierre chan Richard Epstein Ronnie t poon Department of Medicine Queen Mary Hospital Department of Surgery Queen Mary Hospital

Hepatocellular carcinoma (Hcc) commonly occurs in hepatitis B endemic areas, especially in Asian countries. Hcc is highly refractory to cytotoxic chemotherapy. this resistance is partly related to its tumor biology, pharmacokinetic properties, and both intrinsic and acquired drug resistance. there is no convincing evidence thus far that systemic chemotherapy improves overall survival in advanced Hcc patients. Other systemic approaches, such as hormonal therapy and immunotherapy, have also disappointing results. Recently, encouraging results have been shown in using sorafenib in the treatment of advanced Hcc patients. In this review, we concisely summarize the evolution of developments in the systemic therapy of advanced Hcc.

关键词： Advanced hepatocellular carcinoma chemotherapy Doxorubicin Sorafenib

Process development for the direct solvent extraction of nickel and cobalt from nitrate solution:aluminum,cobalt,and nickel separation using cyanex 272

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

International Journal of Minerals,Metallurgy and Materials 2017年第1期24卷 37-46页

作者： Zela t.Ichlas Don c.lbana Leaching and Separation technologies Group Department of Mining Engineering and Metallurgical EngineeringWA School of MinesCurtin UniversityKalgoorlieWA 6430Australia

A direct solvent extraction（DSX） process for purifying nickel and cobalt from the nitric acid leach solution of nickel laterite ores was conceived and experimentally probed. the proposed process consists of two solvent extraction（SX） steps but with only one extractant - bis（2,4,4-trimethylpentyl）phosphinic acid（cyanex？ 272） - used in both steps. the first extraction step involved the removal of aluminum and zinc, whereas the second extraction step involved the separation of cobalt along with manganese from nickel. the experimental results showed essentially quantitative removal of aluminum（〉97%） and zinc（〉99%） in a single extraction stage using 20vol% cyanex 272 at pH 2.1. Some cobalt（32%） and manganese（55%） were co-extracted but were easily scrubbed out completely from the loaded organic phase using dilute sulfuric acid at pH ≤ 1.38. cobalt and manganese in the first extraction raffinate were extracted completely in four extraction stages at staggered pH values of 4.0, 4.4, 4.5, and 4.0 in the first, second, third, and fourth stages, respectively, using also 20vol% cyanex 272. A small amount of nickel（up to 6.6%） was co-extracted but was easily scrubbed out completely with dilute sulfuric acid at pH 2.0. A flow diagram showing the input and output conditions and the metals separated under the deduced optimum conditions is presented.

关键词： solvent extraction aluminum cobalt nickel nickel laterite ores

Bounds on the clique-transversal number of regular graphs

在线全文

学校读者我要写书评

暂无评论

Science china Mathematics 2008年第5期51卷 851-863页

作者： cHENG t.c.E Department of Logistics the Hong Kong Polytechnic University

A clique-transversal set D of a graph G is a set of vertices of G such that D meets all cliques of G. the clique-transversal number, denoted τ c (G), is the minimum cardinality of a clique-transversal set in G. In this paper we present the bounds on the clique-transversal number for regular graphs and characterize the extremal graphs achieving the lower bound. Also, we give the sharp bounds on the clique-transversal number for claw-free cubic graphs and we characterize the extremal graphs achieving the lower bound.

关键词： graph regular graph claw-free cubic graph clique-transversal set clique-transversal number 05c65 05c69 05c75