Cavity dumping of an injection-locked free-electron laser

This letter reports cavity dumping of an electrostatic-accelerator-driven free-electron laser (FEL) while it is injection-locked to a frequency-stabilized 240 GHz solid-state source. Cavity dumping enhances the FEL output power by a factor of $\sim$8, and abruptly cuts off the end of the FEL pulse. The cavity-dumped, injection-locked FEL output is used in a 240 GHz pulsed electron spin resonance (ESR) experiment.Comment: 8 pages including 3 figure

Sub-MHz Linewidth at 240 GHz from an Injection-Locked Free-Electron Laser

Radiation from an ultra-stable 240 GHz solid-state source has been injected, through an isolator, into the cavity of the University of California Santa Barbara (UCSB) MM-wave free-electron laser (FEL). High-power FEL emission, normally distributed among many of the cavity's longitudinal modes, is concentrated into the single mode to which the solid state source has been tuned. The linewidth of the FEL emission is 0.5 MHz, consistent with the Fourier transform limit for the 2 microsecond pulses. This demonstration of frequency-stable, ultra-narrow-band FEL emission is a critical milestone on the road to FEL-based pulsed electron paramagnetic resonance spectroscopy.Comment: 3 pages including 3 figure

Essays on asset pricing and financial regulation

I show that when the banking sector’s assets comprise large excess reserves and loans, jointly determined capital regulation and interest-on-excess-reserves (IOER) policies provide welfare gains. In general equilibrium, falling IOER is associated with a proportional fall in deposit rate only when IOER is above the zero bound. This leads to a faster fall in the bank’s interest expenses than its interest incomes. Given any lending level, lower net interest expenses enhance bank solvency. Nonetheless, the risk-weighted capital regulation remains unchanged and hence becomes socially costly. I show that jointly determined policies achieve welfare gains by loosening the capital requirement and lowering IOER to expand the credit flow, while bank failure likelihood remains constant. Conversely, lowering IOER below the zero bound is associated with a nonresponsive deposit rate that leads to growing net interest expenses and worsening bank solvency. In that case, I show that a stricter capital constraint together with a lower IOER provide social value. The aftermath of the financial crisis inherited heightened economic uncertainty and low productivity. These features prompted the banking sectors across the developed economies to rely heavily on excess reserves offered by the central banks despite the negative nominal IOER policy rate. Nonetheless, the negative relationship between the overall interest expenses of the banking sector with the IOER around the zero lower bound further exacerbates the over-reliance on excess reserves particularly when rates are negative. Financial regulator faces a trade-off between the costly failure of an under-capitalized banking system and costs generated by interconnections between interest expenses on oversized excess reserves and government guarantees to depositors. I show that first, the risk-weighted optimal capital regulation exhibits a negative correlation with the IOER policy rate, and second present a socially optimal financial regulation that balances the social gains of negative IOER rate, generated by reduced over-reliance on idle reserves, against its social costs, generated by the increased default likelihood of the banking institutions.Open Acces

Excitonic Dynamical Franz-Keldysh Effect

The Dynamical Franz-Keldysh Effect is exposed by exploring near-bandgap absorption in the presence of intense THz electric fields. It bridges the gap between the DC Franz- Keldysh effect and multi-photon absorption and competes with the THz AC Stark Effect in shifting the energy of the excitonic resonance. A theoretical model which includes the strong THz field non-perturbatively via a non-equilibrium Green Functions technique is able to describe the Dynamical Franz-Keldysh Effect in the presence of excitonic absorption.Comment: 4 pages in revtex with 5 figures included using epsf. Submitted to Physical Review Letter

Phimosis post-circumcisi: Laporan Kasus

keywords: preputium, kuman anerob, vibrio, spirochete

SISTEM PAKAR DENGAN MENGGUNAKAN METODE DEMPSTER SHAFER UNTUK MENDETEKSI JENIS PERILAKU ABNORMAL ADHD (ATTENTION DEFICIT HYPERACTIVITY DISORDER) PADA ANAK

Minimnya pengetahuan publik tentang perilaku abnormal berakibat perilaku-perilaku abnormal yang ada dan tampak sering dipahami secara keliru, bahkan tidak jarang penyandang perilaku abnormal diperlakukan secara tidak manusiawi. Salah satu bentuk perilaku abnormal tersebut adalah ADHD (Attention Deficit Hyperactivity Disorder) atau gangguan pemusatan perhatian pada anak. Pada penelitian ini, sistem pakar untuk mendeteksi jenis perilaku ADHD memberikan kesimpulan tentang jenis penyakit yang diderita dan tingkat keyakinannya. Digunakan metode Dempster Shafer sebagai metode untuk menghitung nilai kepercayaan atas gejala-gejala yang dipilih pasien. Dengan cara membandingkan setiap nilai bobot dari 2 gejala awal yang dipilih untuk seterusnya dibandingkan dengan nilai bobot gejala-gejala lain, sehingga menghasilkan gejala baru yang mengaju kepada suatu penyakit disertai dengan nilai keyakinannya. Sistem ini diimplementasikan dengan menggunakan bahasa pemograman Microsoft Visual Basic.Net dan dengan menggunakan database Microsoft Access 2013. Hasil pengujian dengan persentase sebesar 85% menunjukkan bahwa sistem pakar ini mampu mendeteksi jenis perilaku ADHD (Attention Deficit Hyperactivity Disorder) yang diderita anak disertai dengan nilai keyakinan Dempster Shafer

Free vibration analysis of sandwich plates with compressible core in contact with fluid

In this paper, the extended higher-order sandwich plate's theory (EHSAPT) is used to analyze the free vibration of the sandwich plate with compressible core and different boundary conditions in contact with fluid. First-order shear deformation theory is adopted for the top and bottom face sheets, while the in-plane and transverse displacements of the core are considered to be cubic and quadratic functions of the transverse coordinate, respectively. A single series is considered with two-variable orthogonal polynomials as a set of admissible functions satisfying the boundary conditions. Besides, the fluid is considered to be irrotational, inviscid and incompressible. By taking into account the boundary conditions and compatibility conditions, the fluid velocity potential is acquired. The natural frequencies of the system are calculated by the Rayleigh-Ritz method. An excellent accuracy is obtained between the results in the available literature and the present method. Finally, the effects of various parameters including boundary conditions, side-to-thickness ratio, thickness of the core to thickness of the face sheets ratio, face sheet to core flexural modulus ratio, dimensions of the container, and aspect ratios on the natural frequencies of the sandwich plate are presented and discussed in detail