Ultrasonic technologies. Physical effects and modern industrial applications

The use of the energy of ultrasonic vibrations in technological processes has found wide industrial application, covering almost all industries, from electronics, instrumentation and ending with mechanical engineering. Powerful ultrasonic vibrations in liquid media cause a number of physical effects in them, which are widely used in various fields of technology. Most of the physical processes occurring in powerful ultrasonic fields are non-linear. The use of ultrasonic technologies makes it possible to carry out a technological effect on the surface layers of materials, which ensures formation of required properties and possibility of creating contact joints in solid phase

Solderability assessment of galvanic coatings in electronics

The problem of providing high-quality soldered joints during the assembly and installation of electronic products draws attention to the use of effective methods for controlling the solderabil-ity of electronic components and func-tional coatings of parts. The solderabil-ity of electroplated coatings used in electronics was studied by two meth-ods: evaluating the spreading of a dosed drop of solder and the wetting force by molten solder. The criteria for evaluating the solderability of coatings are systematized and refined

A new determination of \alpha_s from hadronic \tau\ decays

We present a new framework for the extraction of the strong coupling from hadronic \tau decays through finite-energy sum rules. Our focus is on the small, but still significant non-perturbative effects that, in principle, affect both the central value and the systematic error. We employ a quantitative model in order to accommodate violations of quark-hadron duality, and enforce a consistent treatment of the higher-dimensional contributions of the Operator Product Expansion to our sum rules. Using 1998 OPAL data for the non-strange isovector vector and axial-vector spectral functions, we find the n_f=3 values \alpha_s(m_\tau^2)=0.307+-0.019 in fixed-order perturbation theory, and 0.322+-0.026 in contour-improved perturbation theory. For comparison, the original OPAL analysis of the same data led to the values 0.324+-0.014 (fixed-order) and 0.348+-0.021 (contour-improved).Comment: 31 pages, 7 figures, revtex, version accepted for publication, minor changes, reference adde

Hole Formation in Semiconductor Materials by Laser Microprocessing

The process of laser formation of microholes in semiconductor substrates using an EM-4452-1 laser-processing unit with a pulse repetition frequency of a picosecond laser from 10 to 300 kHz at a radiation energy up to 10 μJ is investigated. The combination of high-speed movements of the laser beam by the galvanoscanner system and precise positioning of the processed material increases the efficiency of laser microprocessing and expands the functional capabilities of the equipment

Air-guided photonic-crystal-fiber pulse-compression delivery of multimegawatt femtosecond laser output for nonlinear-optical imaging and neurosurgery

Cataloged from PDF version of article.Large-core hollow photonic- crystal fibers (PCFs) are shown to enable a fiber-format air-guided delivery of ultrashort infrared laser pulses for neurosurgery and nonlinear-optical imaging. With an appropriate dispersion precompensation, an anomalously dispersive 15-mu m-core hollow PCF compresses 510-fs, 1070-nm light pulses to a pulse width of about 110 fs, providing a peak power in excess of 5 MW. The compressed PCF output is employed to induce a local photodisruption of corpus callosum tissues in mouse brain and is used to generate the third harmonic in brain tissues, which is captured by the PCF and delivered to a detector through the PCF cladding. (C) 2012 American Institute of Physics

Формирование отверстий в кремниевой подложке 3D-электронного модуля лазерным излучением

Laser  heating  is  a  promising  method  for  through-silicon-via  (TSV)  formation  in  assembling  highdensity 3D electronic modules due to its high specific energy and local heating ability. Using laser radiation for the formation of TSV makes it possible to reduce its diameter, indirectly increases the density of elements in 3D electrical  modules.  Laser  system  selection  depends  on  the  physical  and  mechanical  properties  of  the processed materials and on the technical requirements for laserprocessing. The reflectivity of most materials increases with the laser wavelength. It was found that with an increase in the initial temperature of the substrate, the  TSV  taper  becomes  larger.  Simulation  was  performed  in  COMSOL  Multiphysics 5.6  to  conduct  thermal distribution during TSV laser formation. By modeling thermal fields in the COMSOL Multiphysics 5.6 software for  laser  processing  of  silicon  substrates  and  experimental  studies,  the  parameters  of  laser  radiation  have been optimized  to  obtain  a  minimum  hole  taper  coefficient  in  the  substrates  of  3D  electronic  modules. The optimal  duration of  exposure  to  laser radiation  with a  wavelength of 10.64 microns  is  less  than  2 s with holes taper 0.1–0.2.Лазерный нагрев является перспективным методом формирования отверстий в кремниевых подложках  при  сборке  3D-электронных  модулей  с  высокой  плотностью  выводов  из-за  его  высокой удельной  энергии  и  способности  локального  нагрева.  Применение  лазерного  излучения  для формирования  отверстий  в  кремнии  дает  возможность  уменьшения  их диаметра,  косвенно  повышает плотность  элементов  в  3D-электронных  модулях.  Выбор  лазерной  системы  зависит  от  физико-механических  свойств  обрабатываемых  материалов  и  от  технических требований,  предъявляемых к лазерной  обработке.  Отражательная  способность  большинства  материалов  возрастает  с  увеличением длины волны лазерного излучения. Установлено, что с повышением начальной температуры кремниевой подложки конусообразность отверстий в ней становится больше. Выполнено моделирование в COMSOL Multiphysics 5.6 для проведения теплового распределения при лазерной  прошивке  отверстий  в кремниевой подложке. Моделированием тепловых полей в программном пакете COMSOL Multiphysics 5.6 при лазерной обработке кремниевых подложек и экспериментальнымиисследованиями оптимизированы параметры лазерного излучения для получения минимальной конусообразности отверстий в подложках 3D-электронных  модулей.  Оптимальная  длительность  воздействия  лазерного  излучения  с  длиной  волны 10,64 мкм составляет не более 2 с при конусообразности отверстий 0,1–0,2

ПРОГНОЗИРОВАНИЕ МАКСИМАЛЬНО ДОПУСТИМЫХ ПОТЕНЦИАЛОВ РАЗРЯДОВ СТАТИЧЕСКОГО ЭЛЕКТРИЧЕСТВА И ИХ ВЛИЯНИЕ НА ДИОДЫ ШОТТКИ

The forecasting technique of admissible potentials of the static electricity categories of positive and negative polarity with voltage to 15 kV on structures of diodes Shottki with the guard ring is offered.Предложена методика прогнозирования допустимых потенциалов разрядов статического электричества положительной и отрицательной полярности с напряжением до 15 кВ на структуры диодов Шоттки с охранным кольцом

Low-energy constants and condensates from the tau hadronic spectral functions

Diogo Boito, Maarten Golterman, Matthias Jamin, Kim Maltman, and Santiago Peri

The Physics of Hadronic Tau Decays

Hadronic tau decays represent a clean laboratory for the precise study of quantum chromodynamics (QCD). Observables (sum rules) based on the spectral functions of hadronic tau decays can be related to QCD quark-level calculations to determine fundamental quantities like the strong coupling constant, parameters of the chiral Lagrangian, |V_us|, the mass of the strange quark, and to simultaneously test the concept of quark-hadron duality. Using the best available measurements and a revisited analysis of the theoretical framework, the value alpha_s(m_tau) = 0.345 +- 0.004[exp] +- 0.009[theo] is obtained. Taken together with the determination of alpha_s(m_Z) from the global electroweak fit, this result leads to the most accurate test of asymptotic freedom: the value of the logarithmic slope of 1/alpha_s(s) is found to agree with QCD at a precision of 4%. In another approach, the tau spectral functions can be used to determine hadronic quantities that, due to the nonperturbative nature of long-distance QCD, cannot be computed from first principles. An example for this is the contribution from hadronic vacuum polarization to loop-dominated processes like the anomalous magnetic moment of the muon. This article reviews the measurements of nonstrange and strange tau spectral functions and their phenomenological applications.Comment: 89 pages, 32 figures; final version accepted for publication by Reviews of Modern Physic