检索结果-南通市图书馆

Science Bulletin 2018年第20期63卷 1332-1337页

作者： Zhibin Shao Zongyuan Zhang Hui Yuan Haigen Sun Yan Cao Xin Zhang Shaojian Li Habakubaho Gedeon Tao Xiang Qi-Kun Xue Minghu Pan School of Physics Huazhong University of Science and TechnologyWuhan 430074China Institute of Physics Chinese Academy of ScienceBeifing 100190China Collaborative Innovation Center of Quantum Matter Beijing 100084China State Key Laboratory of Low-Dimensional Quantum Physics Tsinghua UniversityBejiing 100084China

Recent experimental and theoretical studies of single-layer FeSe film grown on SrTiO_3 have revealed interface enhanced superconductivity, which opens up a pathway to promote the superconducting transition temperature. Here, to investigate the role of SrTiO_3 substrate in epitaxial superconducting film, we grew a conventional superconductor b-Sn(bulk T_c～ 3.72 K) onto SrTiO_3 substrate by molecular beam epitaxy. By employing scanning tunneling microscope and spectroscopic measurements, an enhanced Tcof 8.2 K is found for epitaxial b-Sn islands, deduced by fitting the temperature dependence of the gap values using the BCS formula. The observed interfacial charge injection and enhanced electron–phonon coupling are responsible for this Tcenhancement. Moreover, the critical field of 8.3 T exhibits a tremendous increase due to the suppression of the vortex formation. Therefore, the coexistence of enhanced superconductivity and high critical field of Sn islands demonstrates a feasible and effective route to improve the superconductivity by growing the islands of conventional superconductors on perovskite-type titanium oxide substrates.

关键词： Sn islands/SrTiO3 Interface-enhanced superconductivity Molecular beam epitaxy scanning tunneling microscope scanning tunneling spectroscopy

scanning tunneling microscopic investigation on morphology of magnetic Weyl semimetal YbMnBi2

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2019年第7期28卷 87-90页

作者： Zhen Zhu Dong Yan Xiao-Ang Nie Hao-Ke Xu Xu Yang Dan-Dan Guan Shiyong Wang Yao-Yi Li Canhua Liu Jun-Wei Liu Hui-Xia Luo Hao Zheng Jin-Feng Jia Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education) Shenyang National Laboratory for Materials Science School of Physics and Astronomy Shanghai Jiao Tong University Shanghai 200240China Department of Physics National Sun Yat-Sen University. Guangzhou 510275 China Collaborative Innovation Center of Advanced Microstructures. Nanjing University Nanjing 210093 China Tsung-Dao Lee Institute Shanghai Jiao Tong University Shanghai 200240China Hong Kong University of Science and Technology Hong Kong China

YbMnBi2 is a recently discovered time-reversal-symmetry breaking type-Ⅱ Weyl ***, as a representation of the new category of topological matters, the scanning tunneling microcopy(STM) results on such important material are still ***, we report the STM investigations on the morphology of vacuum cleaved single crystalline YbMnBi2 samples.A hill and valley type of topography is observed on the YbMnBi2 surface, which is consistent with the non-layer nature of its crystal *** of STM images yields the information of the index of the vicinal *** results here lay a playground of future atomic scale research on YbMnBi2.

关键词： Weyl semimetal topological insulator scanning tunneling microscopy

scanning Mode Application of Neutron-Gamma Analysis for Soil Carbon Mapping

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2019年第3期29卷 334-343页

作者： Aleksandr KAVETSKIY Galina YAKUBOVA Nikolay SARGSYAN Clyde WIKLE Stephen A. PRIOR Henry Allen TORBERT Bryan A. CHIN United States Department of Agriculture-Agricultural Research Service (USDA-ARS) National Soil Dynamics Laboratory Auburn AL 36832 (USA) Auburn University Detection and Food Safety Center Samuel Ginn College of Engineering Auburn AL 36849 (USA)

Soil carbon mapping is extremely useful in assessing the effect of land management practices on soil carbon storage. Applications of neutron-gamma analysis in scanning mode for mapping of soil carbon are discussed. A Global Positioning System(GPS) device and softwares required to simultaneously acquire gamma signals and geographical positions during scanning operations were added to an existing measurement system. The reliability of soil carbon measurements in scanning mode was demonstrated to be in agreement with results acquired from static mode. The error analysis indicated that scanning measurements can be conducted with the same accuracy as static measurements in approximately one fourth the time. To obtain results suitable for mapping analogous to traditional chemical analyses(i.e.,± 0.5 in weight percent or ± 0.5 w%), scanning time over a given site should be ca. 15 min using the current measurement system configuration. Based on this measurement time, a reasonable towing speed of 3–5 km h^-1, the necessity for complete site coverage during scanning, the number of sites(within the surveyed field), and the required total measurement time can be estimated. Soil carbon measurements for 28 field sites(total area ca. 2.5 ha) were conducted in ca. 8 h. Based on acquired data,a soil carbon distribution map was constructed utilizing various softwares. The surveyed field area included an asphalt road that had carbon readings higher than the surrounding land. The clarity with which these carbon-rich zones were delineated on the constructed map represents evidence supporting the veracity of this method. Neutron-gamma analysis technology can greatly facilitate timely construction of soil carbon maps.

关键词： ArcGIS Google Earth Pro IGOR scanning technology soil carbon distribution map soil carbon storage

Fast radial scanning probe system on KTX

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2020年第4期22卷 97-104页

作者： Tijian DENG Tao LAN Mingsheng TAN Junfeng ZHU Jie WU Hangqi XU Chen CHEN Yolbarsop ADIL Sen ZHANG Jiaren WU Yiming ZU Wenzhe MAO Hong LI Jinlin Xie Ahdi LIU Zixi LIU Zhengwei WU Hai WANG Xiaohui WEN Haiyang ZHOU Zian WEI Chijin XIAO Weixing DING Ge ZHUANG Wandong LIU KTX Laboratory and Department of Engineering and Applied Physics University of Science and Technology of ChinaHefei 230026People's Republic of China Plasma Physics Laboratory University of SaskatchewanSaskatoonSK S7N 5E2Canada

A fast radial scanning probe system was constructed for the Keda Torus eXperiment(KTX)to measure the profiles of boundary plasma parameters such as floating potential,electron density,temperature,transport fluxes,*** scanning probe system is driven by slow and fast motion mechanisms,corresponding to the stand-by movement of a stepping motor and the fast scanning movement of a high-torque servo-motor,*** fast scanning,the scanner drives the probe radially up to 20 cm at a maximum velocity of 4.0 m s-1.A noncontact magnetic grating ruler with a high spatial resolution of 5μm is used for the displacement *** scanning probe can reach the center of plasmas *** comparison of plasma floating potential profiles obtained by a fixed radial rake probe and the single scanning probe suggests that the high-speed scanning probe system is reliable for measuring edge plasma parameter profiles on the KTX device.

关键词： radial scanning probe high-speed movement noncontact magnetic grating ruler

A whispering-gallery scanning microprobe for Raman spectroscopy and imaging

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2023年第11期12卷 2402-2410页

作者： Wenbo Mao Yihang Li Xuefeng Jiang Zhiwen Liu Lan Yang Department of Electrical and Systems Engineering Washington UniversitySt LouisMO 63130USA Department of Electrical Engineering Pennsylvania State UniversityUniversity ParkPA 16802USA

Optical whispering-gallery-mode microsensors are a promising platform for many applications,such as biomedical monitoring,magnetic sensing,and vibration ***,like many other micro/nanosensors,they cannot simultaneously have two critical properties–ultrahigh sensitivity and large detection area,which are desired for most sensing ***,we report a novel scanning whispering-gallery-mode microprobe optimized for both features and demonstrate enhanced Raman spectroscopy,providing high-specificity information on molecular fingerprints that are important for numerous sensing *** the superiorities of whispering-gallery modes and nanoplasmonics,the microprobe exhibits a two-orders-of-magnitude sensitivity improvement over traditional plasmonics-only enhancement;this leads to molecular detection demonstrated with stronger target signals but less optical power required than surface-enhanced-Raman-spectroscopy ***,the scanning microprobe greatly expands the effective detection area and realizes two-dimensional micron-resolution Raman imaging of molecular *** versatile and ultrasensitive scanning microprobe configuration will thus benefit material characterization,chemical imaging,and quantum-enhanced sensing.

关键词： microprobe scanning spectroscopy

Equalization of Ti 6Al 4V alloy welded joint by scanning electron beam welding

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

中国有色金属学会会刊：英文版 1999年第3期9卷 535-540页

作者： Chen Xiaofeng(陈晓风) Han Zhong(韩忠) Lou Xinfang(楼新芳) Hu Chuanshun(胡传顺) Sun Changyi(孙长义) Chinese Acad Sci Inst Met Res Shenyang 110015 Peoples R China

The equalization of Ti 6Al 4V alloy welded joint with base metal on corrosion resistance, strength and ductility was studied. The solidification microstructure is transformed from 650 μm columnar grains to 100 μm equiaxed grains by scanning electron beam welding. The anodic polarization curve of 150 μm equiaxed grains coincides with that of base metal. Equal corrosion resistance between weld metal and base metal was obtained. Uniform microstructure and solute distribution are the basis of equalization. Corrosion rate of weld with 150 μm equiaxed grains is the lowest, 2.45 times lower than that of 650 μm columnar grains. Weld strength is 98% as much as that of base metal, yield strength ratio is 99.5%, which is 3.6% higher than that of base metal.

关键词： scanning electron beam welding titanium alloy welding equalizationDocument code: A

Battlefield dynamic scanning and staring imaging system based on fast steering mirror

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2019年第1期30卷 37-56页

作者： CHANG Tianqing WANG Quandong ZHANG Lei HAO Na DAI Wenjun Department of Weapon and Control Army Academy of Armored Forces Center for Assessment and Demonstration Research Academy of Military Sciences Department of Science Research Army Academy of Armored Forces

This paper presents the design of an experimental battlefield dynamic scanning and staring imaging system based on a fast steering mirror(FSM), which is capable of real-time monitoring of hot targets and wide-area reconnaissance of hot regions. First,the working principle and working sequence of the FSM are briefly analyzed. The mathematical model of the FSM system is built by modeling its dynamic and electrical properties, and the rationality of the model is validated by means of model identification. Second,the influence of external sources of disturbance such as the carrier and moment on the control precision of the FSM is effectively suppressed by the jointly controlling of proportional integral(PI)and disturbance observer(DOB), thus realizing a high precision and strong robustness control of the FSM system. Then, this paper designs an experimental prototype and introduces a special optical structure to enable the infrared camera to share the FSM with the visible light camera. Finally, the influence of the velocity difference between the mirror of the FSM and the rotating platform on the imaging quality of the system is experimentally analyzed by using the image sharpness evaluation method based on point sharpness. A good dynamic scanning and staring imaging result is achieved when the velocity of these two components correspond.

关键词： fast steering mirror (FSM) dynamic scanning and staring backscanning compensation disturbance observer (DOB) point sharpness.

Probing non-polarizable liquid/liquid interfaces using scanning ion conductance microscopy

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2020年第3期63卷 411-418页

作者： Yaxiong Gu Ye Chen Yifan Dong Junjie Liu Xianhao Zhang Mingzhi Li Yuanhua Shao Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

The study of microscopic structure of a liquid/liquid interface is of fundamental importance due to its close relation to the thermodynamics and kinetics of interfacial charge transfer *** this article,the microscopic structure of a non-polarizable water/nitrobenzene(W/NB)interface was evaluated by scanning ion conductance microscope(SICM).Using SICM with a nanometer-sized quartz pipette filled with an electrolyte solution as the probe,the thickness of this type of W/NB interface could be measured at sub-nanometer scale,based on the continuous change of ionic current from one phase to another *** effects for thicknesses of the non-polarizable W/NB interfaces with different electrolyte concentrations,the Galvani potentials at the interface and the applied potentials on the probe were measured and systematically *** experimental setups,that is an organic phase up and an aqueous down,and a reverse version,were employed to acquire the approach *** data were compared with those of an ideal polarizable interface under the similar experimental conditions,and several characteristics of non-polarizable interfaces were *** thickness of a non-polarizable interface increases with the decrease of electrolyte concentration and the increase of applied potential,which is similar to the situation of a polarizable liquid/liquid *** also find that the Galvani potential across a non-polarizable interface can also influence the interfacial thickness,this phenomenon is difficult to observe when using polarizable *** importantly,by the comparison of two kinds of liquid/liquid interfaces,we experimentally proved that much more excess ions are gathered in the space charge layer of non-polarizable interfaces than in that of polarizable *** results are consistent with the predictions of molecular dynamic simulations and X-ray reflectivity measurements.

关键词： micro/nano pipettes scanning ion conductance microscopy microstructure of a non-polarizable liquid/liquid interface

Resolution and contrast enhancement of laser-scanning multiphoton microscopy using thulium-doped upconversion nanoparticles

在线全文

学校读者我要写书评

暂无评论

Nano Research 2019年第12期12卷 2933-2940页

作者： Alexey B.Kostyuk Artem D.Vorotnov Andrey V.Ivanov Arthur B.Volovetskiy Aleksandr V.Kruglov Lyudmila M.Sencha Liuen Liang Evgenii L.Guryev Vladimir A.Vodeneev Sergey M.Deyev Yiqing Lu Andrei V.Zvyagin Lobachevsky State University of Nizhny Novgorod Nizhny Novgorod 603950Russia Center of Biomedical Engineering Institute of Molecular MedicineSechenov UniversityMoscow 119991Russia ARC Centre of Excellence"Nanoscale BioPhotonics" Department of Physics and AstronomyMacquarie UniversitySydney 2109Australia Institute ofBioorganic Chemistry Russian Academy of SciencesMoscow 117997Russia

High-contrast optical imagi ng is achievable using phosphoresce nt labels to suppress the short-lived background due to the optical backscatterand autofluoresce ***,the long-lived phosphorescence is generally incompatible with high-speed laser-scan ning imaging ***,we show that upc on versi on nan oparticles of structure NaYF4:Yb co-doped with 8%Tm(8T-UCNP)in combi nation with a commerciallaser-scanning multiphoton microscopy are uniquely suited for labeling biological systems to acquire high-resolution images with the enhancedcon *** comparison with many phosphoresce nt labels,the 8T-UCNP emission lifetime of-15μs affords rapid image ***-order optical nonlinearity of the 8T-UCNP(n=4,as confirmed experimentally and theoretically)afforded pushing the resolution limitattain able with UCNPs to the *** contrast enha nceme nt was achieved by suppressing the backgro und using(i)ban dpassspectral filtering of the narrow emission peak of 8T-UCNP at 455-nm,and(ii)time-gating implemented with a time-correlated single-photon counting system that demonstrated the contrast enhancement of>2.5-fold of polyethyle neimine-coated 8T-UCNPs take n up by huma nbreast adeno carcinoma cells *** a result,discrete 8T-UCNP nan oparticles became clearly observable in the freshly excised splee ntissue of laboratory mice 15-min post in trave nous injectio n of an 8T-UCNP *** dem on strated approach paves the way forhigh-contrast,high-resoluti on,and high-speed multiphot on microscopy in challe nging envir onments of i ntense autofluorescence,exogenous staining,and turbidity,as typically occur in intravital imaging.

关键词： upconversion nanoparticles autofluorescence time-gated imaging scanning microscopy time-correlated single photon counting

MEMS-in-the-lens architecture for a miniature high-NA laser scanning microscope

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

Light(Science & Applications) 2019年第1期8卷 665-675页

作者： Tianbo Liu Milind Rajadhyaksha David L.Dickensheets Electrical and Computer Engineering Department Montana State UniversityBozemanMT 59715USA Dermatology Department Memorial Sloan Kettering Cancer CenterNew YorkNY 10022USA

Laser scanning microscopes can be miniaturized for in vivo imaging by substituting optical microelectromechanical system(MEMS)devices in place of larger *** emergence of multifunctional active optical devices can support further miniaturization beyond direct component replacement because those active devices enable diffraction-limited performance using simpler optical system *** this paper,we propose a catadioptric microscope objective lens that features an integrated MEMS device for performing biaxial scanning,axial focus adjustment,and control of spherical *** MEMS-in-the-lens architecture incorporates a reflective MEMS scanner between a low-numerical-aperture back lens group and an aplanatic hyperhemisphere front refractive element to support high-numerical-aperture *** implemented this new optical system using a recently developed hybrid polymer/silicon MEMS three-dimensional scan mirror that features an annular aperture that allows it to be coaxially aligned within the objective lens without the need for a beam *** optical performance of the active catadioptric system is simulated and imaging of hard targets and human cheek cells is demonstrated with a confocal microscope that is based on the new objective lens design.

关键词： scanning scanner mirror