Toroidal dipole induced transparency for core-shell nanoparticles

We investigate the scattering properties of spherical nanoparticles by employing a Cartesian multipole expansion method which has incorporated radiating toroidal multipoles. It is shown that toroidal dipoles, which are negligible under long-wavelength approximations, can be excited within high-permittivity dielectric nanoparticles and significantly influence the scattering profile in the optical regime. We further reveal that the scattering transparencies of core-shell plasmonic nanoparticles can be classified into two categories: i) the trivial transparency with no effective multipole excitations within the particle, and ii) the non-trivial one induced by the destructive interferences of induced electric and toroidal multipoles. The incorporation of toroidal moments offers new insights into the study into nanoparticle scattering in both the near- and far-fields, which may shed new light to many related applications, such as biosensing, nanoantennas, photovoltaic devices and so on.Comment: 15 pages and 3 figure

Market expansion, state intervention and wage differentials between economic sectors in urban China : a multilevel analysis

This work was supported by the National Natural Science Foundation of China (41501151, 41329001); the China Ministry of Education (11JJDZH006); the National Key Technology R&D Program (2012BAI32B07); and the Research Centre for Urban and Regional Development, Hong Kong Institute of Asia-Pacific Studies. This research is also supported by the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning.The rising earnings inequality in China has sparked a heated debate on the socioeconomic outcomes of market transformation. While a large body of literature has focussed on the temporal trend of wage inequality during the reform period, much less attention has been devoted to the structural causes of regional variations in sectoral wage differentials. Using a micro-data sample from the 2005 one percent population sample survey and multilevel methods, this article examines the geographic variability of wage differentials between economic sectors in urban China, with a particular focus on the combination effects of market expansion and state intervention. The results indicate that sectoral wage differentials vary substantially across regions, and that market expansion interacts with state intervention to reconfigure earnings outcomes. Specifically, prefectures located in the interior region tend to exhibit a large wage premium for the state sectors, while prefectures located in the coastal region tend to display a wage advantage of the foreign-invested sector. The wage gap between the state and non-state sectors is smaller in areas with diversified ownership; openness to foreign investment increases the relative wages of foreign-invested-sector employees; stringent government regulation of industries increases the wage gap between the state monopoly sector and the non-monopoly sector; and strong redistributive power increases the wage premium for the public service sector over other sectors. Our findings suggest the necessity to take into account contextually constituted and locally specific wage-setting mechanisms when studying China’s wage inequality.Publisher PDFPeer reviewe

Invisible nanowires with interfering electric and toroidal dipoles

By studying the scattering of normally incident plane waves by a single nanowire, we reveal the indispensable role of toroidal multipole excitation in multipole expansions of radiating sources. It is found that for both p-polarized and s-polarized incident waves, toroidal dipoles can be effectively excited within homogenous dielectric nanowires in the optical spectrum regime. We further demonstrate that the plasmonic core–shell nanowires can be rendered invisible through destructive interference of the electric and toroidal dipoles, which may inspire many nano-wire-based light–matter interaction studies, and incubate biological and medical applications that require non-invasive detections and measurements

Epidemiological analysis of hydrometra and its predictive value in gynecological tumors

IntroductionHydrometra is a common gynecological disease, especially in postmenopausal women. However, its epidemiology, harmfulness, and value in predicting gynecological tumors have not been clearly elucidated.MethodsIn this study, the prevalence rate of and risk factors for hydrometra were investigated in 3,903 women who underwent screening for gynecological diseases at Zhoupu Hospital in Shanghai from 1 January to 31 December 2021. In addition, pathological distribution of hydrometra and its predictive value in gynecological tumors were studied in another 186 patients in whom hydrometra was diagnosed sonographically at Zhoupu Hospital, from 1 January 2020 to 31 December 2021, and who underwent hysteroscopy and postoperative pathological examination.ResultsThe observed prevalence rate of hydrometra was 10.86%, which was higher than the prevalence of other gynecological diseases. Univariate and multivariate analysis indicated that advanced age (OR 1.11) and vaginitis (OR 3.18) were independent risk factors for hydrometra. Among 186 patients with a sonographic diagnosis of uterine fluid, simple hydrometra accounted for 34.41% of cases, inflammation accounted for 16.23%, and hematometra accounted for 2.15%, while gynecological tumors accounted for 5.91%. Moreover, univariate and multivariate analysis indicated that a higher body mass index (>23.92 kg/m2), greater hydrometra volume (i.e., distance between the two layers of endometrium>4.75 mm), and abnormal vaginal bleeding were high-risk predictive factors for gynecological tumors.DiscussionIn conclusion, hydrometra is a common disease, and is a risk factor for endometrial cancer and cervical cancer, especially in patients with higher hydrometra volume, higher BMI, and abnormal vaginal bleeding. It is necessary to pay more attention to hydrometra

Visualizing the Zhang-Rice singlet, molecular orbitals and pair formation in cuprate

The parent compound of cuprates is a charge-transfer-type Mott insulator with strong hybridization between the Cu $3d_{\mathrm x^2-y^2}$ and O $2p$ orbitals. A key question concerning the pairing mechanism is the behavior of doped holes in the antiferromagnetic (AF) Mott insulator background, which is a prototypical quantum many-body problem. It was proposed that doped hole on the O site tends to form a singlet, known as Zhang-Rice singlet (ZRS), with the unpaired Cu spin. But experimentally little is known about the properties of a single hole and the interplay between them that leads to superconductivity. Here we use scanning tunneling microscopy to visualize the electronic states in hole-doped $\mathrm{Ca_2CuO_2Cl_2}$, aiming to establish the atomic-scale local basis for pair formation. A single doped hole is shown to have an in-gap state and a clover-shaped spatial distribution that can be attributed to a localized ZRS. When the dopants are close enough, they develop delocalized molecular orbitals with characteristic stripe- and ladder-shaped patterns, accompanied by the opening of a small gap around the Fermi level ($E_{\mathrm F}$). With increasing doping, the molecular orbitals proliferate in space and gradually form densely packed plaquettes, but the stripe and ladder patterns remain nearly the same. The low-energy electronic states of the molecular orbitals are intimately related to the local pairing properties, thus play a vitally important role in the emergence of superconductivity. We propose that the Cooper pair is formed by two holes occupying the stripe-like molecular orbital, while the attractive interaction is mediated by the AF spin background