Conic singularities metrics with prescribed scalar curvature: a priori estimates for normal crossing divisors

The purpose of this paper is to prove the a priori estimates for constant scalar curvature Kaehler metrics with conic singularities along normal crossing divisors. The zero order estimates are proved by a reformulated version of Alexandrov's maximum principle. The higher order estimates follow from Chen-Cheng's frame work, equipped with new techniques to handle the singularities. Finally, we extend these estimates to the twisted equations

Tungsten disulfide-gold nanohole hybrid metasurfaces for nonlinear metalens in the visible region

Recently, nonlinear hybrid metasurface comes into an attractive new concept in the research of nanophotonics and nanotechnology. It is composed of semiconductors with an intrinsically large nonlinear susceptibility and traditional plasmonic metasurfaces, offering opportunities for efficiently generating and manipulating nonlinear optical responses. A high second-harmonic generation (SHG) conversion efficiency has been demonstrated in the mid-infrared region by using multi-quantum-well (MQW) based plasmonic metasurfaces. However, it has yet to be demonstrated in the visible region. Here we present a new type of nonlinear hybrid metasurfaces for the visible region, which consists of a single layer of tungsten disulfide (WS2) and a phased gold nanohole array. The results indicate that a large SHG susceptibility of ~0.1 nm/V at 810 nm is achieved, which is 2~3 orders of magnitude larger than that of typical plasmonic metasurfaces. Nonlinear metalenses with the focal lengths of 30 {\mu}m, 50 {\mu}m and 100 {\mu}m are demonstrated experimentally, providing a direct evidence for both generating and manipulating SH signals based on the nonlinear hybrid metasurfaces. It shows great potential applications in designing of integrated, ultra-thin, compacted and efficient nonlinear optical devices, such as frequency converters, nonlinear holography and generation of nonlinear optical vortex beam

Implementasi Kontrol Integritas E-kiosk untuk Pengamanan Sistem Pemungutan Suara secara Elektronik (E-VOTING)

Pemungutan suara dalam pemilu di Indonesia masih dilakukan secara manual, yaitu menggunakan media kertas. Dalam sistem tersebut, terjadi risiko kesalahan yang tinggi dalam penghitungan suara mengingat surat suara yang diproses terbilang banyak. Selain itu, rawan terjadi kecurangan terhadap jumlah suara demi memenangkan kelompok atau golongan tertentu. Akibatnya, pelaksanaan pemilu menjadi tidak sesuai dengan asas yang berlaku dan hasilnya tidak akurat. Untuk mengatasinya, dirancanglah sistem pemungutan suara yang lebih modern, yang disebut dengan sistem pemungutan suara secara elektronik (e-voting)