Large-scale Google Street View Images for Urban Change Detection

Urbanization has entered a new phase characterized by urban changes occurring at a micro-scale and “under the roof”, as opposed to external modifications. These changes, known as urban retrofitting, involve the incorporation of novel technologies or features into pre-existing systems to promote sustainability. Given the limitations of remote sensing images in identifying such urban changes, novel tools need to be developed for detecting urban retrofitting. In this study, we first build a pipeline to collect large-scale time-series urban street view images from Google Street View in Mecklenburg County, North Carolina. And we examine the feasibility of utilizing the acquired dataset to detect diverse forms of urban retrofitting, including re-building, re-greening and re-capital

Growing Business in Live Commerce: A Tripartite Perspective and Product Heterogeneity

Live streaming becomes an important channel helping organizations and individual sellers boost their sales. Our research takes an integrated perspective and examines the simultaneous influences of streamers-, consumers-, and products-related factors on sales volume in live commerce. We apply multiple linear regression to analyze a panel data set collected from Taobao live in Double 11, 2020, which contained 34,925 product sales records. We find that streamers’ social capital, consumers’ engagement, and products’ live demonstration all significantly contribute to product sales volume. In addition, product heterogeneity matters in live commerce such that the effects of streamers’ social capital and products’ live demonstration on sales volume work only for experience products (not for search products) and for the products with less popular brands (not for the products with popular brands). Our research offers comprehensive insights for both researchers and practitioners on how to grow business in live commerce

NMR Study of Ba8Cu5SixGe41-x Clathrate Semiconductors

We have performed 63Cu, 65Cu, and 137Ba NMR on Ba8Cu5SixGe41-x, a series of intermetallic clathrates known for their potential as thermoelectric materials, in order to investigate the electronic behavior of the samples. The spectra and spin - lattice relaxation times were measured at 77 K and 290 K for the entire composition range 0 <= x <= 41. Magnetic and quadrupole shifts and relaxation rates of the Cu NMR data were extracted, and thereby carrier-induced metallic contributions identified. The observed shifts change in a nonlinear way with increasing Si substitution: from x = 0 to about 20 the shifts are essentially constant, while approaching x = 41 they increase rapidly. At the same time, Ba NMR data indicate greater Ba-site participation in the conduction band in Ba8Cu5Si41 than in Ba8Cu5Ge41. The results indicate surprisingly little change in electronic features vs. Si content for most of the composition range, while Ba8Cu5Si41 exhibits enhanced hybridization and a more metallic framework than Ba8Cu5Ge41.Robert A. Welch Foundation, Grant No. A-1526. Austrian Science Fund, FWF project TRP 176-N22

Quenching a Weyl-Kondo semimetal by magnetic field

With the advent of topology in electronic materials the number of predicted quantum phases has literally exploded. Most of them, however, still await firm experimental identification. In strongly correlated electron systems, scanning their low-temperature phase diagrams by varying a nonthermal control parameter has been instrumental in delineating phases defined by a Landau order parameter. Here we show that this approach is versatile also for strongly correlated topological phases. We use Hall effect measurements to probe how the time reversal symmetry invariant Weyl-Kondo semimetal Ce$_3$Bi$_4$Pd$_3$ transforms under magnetic-field tuning. We detect an intriguing two-stage transition, which we associate with an annihilation of the Weyl nodes, making the system more insulating, and a consecutive transition to a heavy fermion metal phase. We expect our work to stimulate tuning studies in related systems, thereby advancing the much needed identification of organizing principles for strongly correlated electronic topology.Comment: 4 figures, 19 page

Anti-icing property of bio-inspired micro-structure superhydrophobic surfaces and heat transfer model

Ice accumulation is a thorny problem which may inflict serious damage even disasters in many areas, such as aircraft, power line maintenance, offshore oil platform and locators of ships. Recent researches have shed light on some promising bio-inspired anti-icing strategies to solve this problem. Inspired by typical plant surfaces with super-hydrophobic character such as lotus leaves and rose petals, structured superhydrophobic surface are prepared to discuss the anti-icing property. 7075 Al alloy, an extensively used materials in aircrafts and marine vessels, is employed as the substrates. As-prepared surfaces are acquired by laser processing after being modified by stearic acid for 1 h at room temperature. The surface morphology, chemical composition and wettability are characterized by means of SEM, XPS, Fourier transform infrared (FTIR) spectroscopy and contact angle measurements. The morphologies of structured as-prepared samples include round hump, square protuberance and mountain-range-like structure, and that the as-prepared structured surfaces shows an excellent superhydrophobic property with a WCA as high as 166 ± 2°. Furthermore, the anti-icing property of as-prepared surfaces was tested by a self-established apparatus, and the crystallization process of a cooling water on the sample was recorded. More importantly, we introduced a model to analyze heat transfer process between the droplet and the structured surfaces. This study offers an insight into understanding the heat transfer process of the superhydrophobic surface, so as to further research about its unique property against ice accumulation

On the constitution and thermodynamic modeling of the phase diagrams Nb-Mn and Ta-Mn

The constitution of the two phase diagrams Nb-Mn and Ta-Mn has been determined from light optical and transmission and scanning electron microscopy (LOM, TEM and SEM) with energy dispersive (EDX) as well as wavelength dispersive (WDX) X-ray spectroscopy, X-ray powder (XPD) and single crystal diffraction (XSCD), differential thermal analysis (DTA) and/or differential scanning calorimetry (DSC). The Laves phases NbMn2 and TaMn2 are the only binary compounds in these systems. High-temperature differential thermal analyses revealed congruent melting for NbMn2 with T,(NbMn2) = 1515 +/- 15 degrees C, whereas TaMn2 melts incongruently with T-m(TaMn2)= 1797 +/- 40 degrees C close to a depleted peritectic reaction. Both Laves phases engage in eutectic reactions l (Mn) + Nb(Ta)Mn-2 (T-eut = 1220 +/- 10 degrees C at 4.9 at% Nb and T-eut = 1234 +/- 10 degrees C at 0.7 at% Ta, respectively). NbMn2 also forms a eutectic with (Nb): l (Nb) + NbMn2 at T-eut = 1493 +/- 15 degrees C and 53.2 at% Nb. Mn shows remarkably large maximum solid solubilities of 19.4 at% Mn in (Nb) as well as of 21.3 at% Mn in (Ta). Detailed atom site distribution has been established for the Laves phases by means of temperature dependent X-ray single crystal data (both C14 - MgZn2-type). Combined data from XPD, EDX/WDX and SEM microstructure indicate that for both Laves phases extended homogeneity regions exist: Nb1+xMn2+x (62.5-73.0 at% Mn at 950 degrees C: -0.19 <= x <= 1.125) and Ta1+xMn2-x (59.5-68.5 at % Mn: -0.055 <= x <= 1.215). Density functional theory (DFT) calculations favor Nb(Ta)/Mn antisite occupation rather than defects. The phases, "NbMn" and "TaMn", adopted earlier in the literature as binary system inherent compounds, were shown (TEM, WDX electron microprobe data and X-ray Rietveld refinements) to be oxygen stabilized phases of the Ti4Ni2O type (so-called eta(eta)-phases) with modified Nb(Ta)/Mn site substitution to comply with the formula Nb(Ta)(3-x)Mn3+xO1-y (defect eta-W3Fe3C-type). From magnetic susceptibility and magnetization measurements, both oxide stabilized eta phases eta-Nb3Mn3O1-y and eta-Ta3Mn3O1-y were found to order ferromagnetically below T-c similar to 77 K, but the Laves phases NbMn2, TaMn2 reveal weakly temperature dependent paramagnetism. No trace of the rhombohedral kyphase (W6Fe7-type) has been encountered in our investigation of the two binary phase diagrams. Thermodynamic and transport properties (specific heat, electrical resistivity and magnetic susceptibility/magnetization) classify the Laves phases with metallic behavior whilst mechanical properties (elastic moduli from DFT and nanoindentation as well as hardness and thermal expansion) group both Laves phases among rather hard and brittle intermetallics. Based on (i) the experimentally derived constitution of the Nb-Mn and Ta-Mn systems, and (ii) on new own DFT data of the energy of formation of the Laves phases, a CALPHAD (CALculation of PHAse Diagrams) calculation of both systems was made providing a complete set of optimized thermodynamic data. Furthermore, the DFT calculations provided information on the instability of the eta-Ta3Mn3 structure and the atom-site specific stabilization effect of oxygen.Web of Science865art. no. 15871

Viral neutralization by antibody-imposed physical disruption

中和抗体是机体抵御病毒入侵的一类免疫球蛋白，也是疫苗发挥作用的主要效应分子。目前已知的中和抗体作用机制，主要包括阻断病毒-细胞相互作用和介导免疫调理作用。最近我校夏宁邵教授团队研究结果揭示了一种由抗体诱导病毒原位崩解的中和新机制。该研究首次揭示了抗体的直接物理碰撞中和机制，并提出诱导这类中和抗体的方法，有助于病毒保护性抗体和疫苗设计，适用于多种病原体，而不仅限于戊型肝炎病毒。分子疫苗学和分子诊断学国家重点实验室夏宁邵教授、李少伟教授和顾颖副教授为该论文的共同通讯作者，郑清炳博士、硕士生蒋婕、博士生何茂洲和郑子峥副教授为共同第一作者。In adaptive immunity, organisms produce neutralizing antibodies (nAbs) to eliminate invading pathogens. Here, we explored whether viral neutralization could be attained through the physical disruption of a virus upon nAb binding. We report the neutralization mechanism of a potent nAb 8C11 against the hepatitis E virus (HEV), a nonenveloped positive-sense single-stranded RNA virus associated with abundant acute hepatitis. The 8C11 binding flanks the protrusion spike of the HEV viruslike particles (VLPs) and leads to tremendous physical collision between the antibody and the capsid, dissociating the VLPs into homodimer species within 2 h. Cryo-electron microscopy reconstruction of the dissociation intermediates at an earlier (15-min) stage revealed smeared protrusion spikes and a loss of icosahedral symmetry with the capsid core remaining unchanged. This structural disruption leads to the presence of only a few native HEV virions in the ultracentrifugation pellet and exposes the viral genome. Conceptually, we propose a strategy to raise collision-inducing nAbs against single spike moieties that feature in the context of the entire pathogen at positions where the neighboring space cannot afford to accommodate an antibody. This rationale may facilitate unique vaccine development and antimicrobial antibody design.This research was supported by grants from the Natural Science Foundation of Fujian Province (Grant 2017J07005), the National Science and Technology Major Project of Infectious Diseases (Grant 2018ZX10101001-002), and the National Natural Science Foundation of China (Grants 81871247, 81991490, and 81571996).国家自然科学基金重大项目、海峡联合项目和面上项目、福建省自然科学杰出青年基金、国家传染病科技重大专项等资助了该项研究