LED and Phototransistor Simulation

Optoelectronics (e.g., light-emitting diodes, photodetectors) is one of the most widely used fields nowadays. But it is still necessary to improve their characteristics for using in general lighting. In this chapter, the heterostructure conductivity type, impurity and indium atoms influence on the LEDs and phototransistor characteristics are investigated by computer simulation. It was found that current-voltage characteristic and quantum efficiency depend on impurity and indium atoms change a lot. By varying impurity and indium atom concentration, controlling their distribution in InGaN and AlGaP heterostructure LEDs and photodetector characteristics can be improved

Physics case for an LHCb Upgrade II - Opportunities in flavour physics, and beyond, in the HL-LHC era

The LHCb Upgrade II will fully exploit the flavour-physics opportunities of the HL-LHC, and study additional physics topics that take advantage of the forward acceptance of the LHCb spectrometer. The LHCb Upgrade I will begin operation in 2020. Consolidation will occur, and modest enhancements of the Upgrade I detector will be installed, in Long Shutdown 3 of the LHC (2025) and these are discussed here. The main Upgrade II detector will be installed in long shutdown 4 of the LHC (2030) and will build on the strengths of the current LHCb experiment and the Upgrade I. It will operate at a luminosity up to 2×1034 cm−2s−1, ten times that of the Upgrade I detector. New detector components will improve the intrinsic performance of the experiment in certain key areas. An Expression Of Interest proposing Upgrade II was submitted in February 2017. The physics case for the Upgrade II is presented here in more depth. CP-violating phases will be measured with precisions unattainable at any other envisaged facility. The experiment will probe b → sl+l−and b → dl+l− transitions in both muon and electron decays in modes not accessible at Upgrade I. Minimal flavour violation will be tested with a precision measurement of the ratio of B(B0 → μ+μ−)/B(Bs → μ+μ−). Probing charm CP violation at the 10−5 level may result in its long sought discovery. Major advances in hadron spectroscopy will be possible, which will be powerful probes of low energy QCD. Upgrade II potentially will have the highest sensitivity of all the LHC experiments on the Higgs to charm-quark couplings. Generically, the new physics mass scale probed, for fixed couplings, will almost double compared with the pre-HL-LHC era; this extended reach for flavour physics is similar to that which would be achieved by the HE-LHC proposal for the energy frontier

LHCb upgrade software and computing : technical design report

This document reports the Research and Development activities that are carried out in the software and computing domains in view of the upgrade of the LHCb experiment. The implementation of a full software trigger implies major changes in the core software framework, in the event data model, and in the reconstruction algorithms. The increase of the data volumes for both real and simulated datasets requires a corresponding scaling of the distributed computing infrastructure. An implementation plan in both domains is presented, together with a risk assessment analysis

Multidifferential study of identified charged hadron distributions in ZZ-tagged jets in proton-proton collisions at s=\sqrt{s}=13 TeV

Jet fragmentation functions are measured for the first time in proton-proton collisions for charged pions, kaons, and protons within jets recoiling against a $Z$ boson. The charged-hadron distributions are studied longitudinally and transversely to the jet direction for jets with transverse momentum 20 $< p_{\textrm{T}} < 100$ GeV and in the pseudorapidity range $2.5 < \eta < 4$. The data sample was collected with the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.64 fb$^{-1}$. Triple differential distributions as a function of the hadron longitudinal momentum fraction, hadron transverse momentum, and jet transverse momentum are also measured for the first time. This helps constrain transverse-momentum-dependent fragmentation functions. Differences in the shapes and magnitudes of the measured distributions for the different hadron species provide insights into the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb public pages

Study of the B−→Λc+Λˉc−K−B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} decay

The decay $B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-}$ is studied in proton-proton collisions at a center-of-mass energy of $\sqrt{s}=13$ TeV using data corresponding to an integrated luminosity of 5 $\mathrm{fb}^{-1}$ collected by the LHCb experiment. In the $\Lambda_{c}^+ K^{-}$ system, the $\Xi_{c}(2930)^{0}$ state observed at the BaBar and Belle experiments is resolved into two narrower states, $\Xi_{c}(2923)^{0}$ and $\Xi_{c}(2939)^{0}$, whose masses and widths are measured to be $$m(\Xi_{c}(2923)^{0}) = 2924.5 \pm 0.4 \pm 1.1 \,\mathrm{MeV}, \\ m(\Xi_{c}(2939)^{0}) = 2938.5 \pm 0.9 \pm 2.3 \,\mathrm{MeV}, \\ \Gamma(\Xi_{c}(2923)^{0}) = \phantom{000}4.8 \pm 0.9 \pm 1.5 \,\mathrm{MeV},\\ \Gamma(\Xi_{c}(2939)^{0}) = \phantom{00}11.0 \pm 1.9 \pm 7.5 \,\mathrm{MeV},$$ where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt $\Lambda_{c}^{+} K^{-}$ sample. Evidence of a new $\Xi_{c}(2880)^{0}$ state is found with a local significance of $3.8\,\sigma$, whose mass and width are measured to be $2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV}$ and $12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}$, respectively. In addition, evidence of a new decay mode $\Xi_{c}(2790)^{0} \to \Lambda_{c}^{+} K^{-}$ is found with a significance of $3.7\,\sigma$. The relative branching fraction of $B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-}$ with respect to the $B^{-} \to D^{+} D^{-} K^{-}$ decay is measured to be $2.36 \pm 0.11 \pm 0.22 \pm 0.25$, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb public pages

Measurement of the ratios of branching fractions R(D∗)\mathcal{R}(D^{*}) and R(D0)\mathcal{R}(D^{0})

The ratios of branching fractions $\mathcal{R}(D^{*})\equiv\mathcal{B}(\bar{B}\to D^{*}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}\to D^{*}\mu^{-}\bar{\nu}_{\mu})$ and $\mathcal{R}(D^{0})\equiv\mathcal{B}(B^{-}\to D^{0}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(B^{-}\to D^{0}\mu^{-}\bar{\nu}_{\mu})$ are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb${ }^{-1}$ of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode $\tau^{-}\to\mu^{-}\nu_{\tau}\bar{\nu}_{\mu}$. The measured values are $\mathcal{R}(D^{*})=0.281\pm0.018\pm0.024$ and $\mathcal{R}(D^{0})=0.441\pm0.060\pm0.066$, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is $\rho=-0.43$. Results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb public pages

The development of an interactive database for assessing the ecological and geomorphic state of aquatic ecosystems

The paper discusses the basic principles of using geoinformation technologies to study relief-forming processes and the ecological state of aquatic ecosystems. The object of the study is the territory of the city of Sevastopol within the valleys of the Chernaya, Kacha and Belbek rivers. To conduct environmental monitoring, it is proposed to use field and chemical-analytical methods. According to the data obtained, information and analytical maps with a geodatabase are produced. Creation of an information and analytical map with a database using GIS toolkit makes it possible to identify factors influencing the deformation of the river bed and changes in the ecological state of aquatic ecosystems. The proposed technology for monitoring the study area allows saving data, using them in projects, and supplementing these data as new information becomes available

Роль ортезування в разі ушкодження передньої схрещеної зв’язки

The use of orthoses and braces in patients with damage to the anterior cruciate ligament and post-arthroscopic re­construction is a fairly widespread phenomenon.Objective: to determine the effectiveness of the application of orthoses of various structures in patients with anterior cruciate liga­ment injury using hardware-software baseometric complex.Methods: 50 patients with anterior cruciate ligament damage and 50 healthy volunteers were screened. Bazometric study with the help of the hardware-software baseometric complex (baseometer) KE 03191680.010-2005 of the UkrNII prosthesis production was carried out without a latch and using 4 types of knee joint fasteners. The parameters of two-stops stand­ing on the base-platform were analyzed: load distribution (%) of the total body mass between the lower extremities, incapacitability, displacement of the general pressure center in the fron­tal and sagittal planes, and the rotation of the general pressure center.Results: in patients with injuries of anterior cruciate ligament, a significant prevalence of body mass distribution for the intact lower limb was found to be significant (73.3 ± 2.8) and (26.7 ± 1.6) %, respectively; the weight bearing factor was 0.36 ± 0.4; displacement of the general CT in the frontal plane — (11.5 ± 1.1) mm; in the sagital — (7.2 ± 1.0) mm; rotating angle of the general pressure center — (7.8 ± 1.2)°. Under the condi­tions of the use of fixators, depending on their type, a tendency to reduce the asymmetry of the body weight distribution between the limbs is determined.Conclusions: as a result of the survey of healthy volunteers, the main indicators of the two-limb stand­ing on the base-platform were obtained. The analysis of base­line rates of patients with anterior cruciate ligament injury showed a significant deviation compared with the group of volunteers. Among the studied designs of knee joint fixation de­vices, the knee joint with a two-axis hinge was most functionally suitable. It allows the maximum correction and improvement of biomechanical indicators of statics and fatigue of the injured limb.Применение ортезов и брейсов у пациентов с повреждением передней крестообразной связки (ПКС) и после артроскопической реконструкции — довольно распространенное явление.Цель: определить эффективность применения ортезов различных конструкций у пациентов с повреждением ПКС с помощью аппаратно-программного базометричного комплекса.Методы: обследовано 50 пациентов с повреждением ПКС и 50 здоровых добровольцев. Базометричне исследования с помощью аппаратно-программного базометричного комплекса (базометра) КЭ 03191680.010-2005 производства УкрНИИ протезирования произведено без фиксатора и с использованием 4 видов фиксаторов коленного сустава. Анализировали параметры двухопорного стояния на базометричний платформе: распределение нагрузки (%) от общей массы тела между нижними конечностями, коэффициент опороспособности, смещение общего центра давления (ЦД) в передней и сагиттальной плоскостях, ротацию ЦД.Результаты: у пациентов с повреждением ПКС выявлено достоверное преобладание распределения массы тела на интактную нижнюю конечность по сравнению с травмированной — (73,3 ± 2,8) и (26,7 ± 1,6) % соответственно; коэффициент опороспособности равен 0,36 ± 0,4; смещение общего ЦД во фронтальной плоскости — (11,5 ± 1,1) мм; в сагиттальной — (7,2 ± 1,0) мм; угол ротации ЦД — (7,8 ± 1,2)°. В условиях применения фиксаторов в зависимости от их вида определена тенденция к уменьшению асимметрии распределения массы тела пациента между конечностями.Выводы: в результате обследования группы здоровых волонтеров получены основные показатели двухопорного стояния на базометричний платформе. Анализ базометричних показателей пациентов с повреждением ПКС показал значительное их отклонение по сравнению с группой волонтеров. Среди изученных конструкций фиксаторов коленного сустава наиболее функционально пригодным оказался наколенник с двухосным шарниром. Он позволяет максимально скорректировать и улучшить биомеханические показатели статики и опороспособность травмированной конечности.Застосування ортезів і брейсів у пацієнтів із ушкодженням передньої схрещеної зв’язки (ПСЗ) і після артроскопічної реконструкції — досить поширене явище.Мета: визначити ефективність застосування ортезів різних конструкцій у пацієнтів із ушкодженням ПСЗ за допомогою апаратно-про­грамного базометричного комплексу.Методи: обстежено 50 пацієнтів із ушкодженням ПСЗ і 50 здорових волонтерів. Базометричне дослідження за допомогою апаратно-програмного базометричного комплексу (базометра) КЕ 03191680.010-2005 виробництва УкрНДІ протезування проведено без фіксатора і з використанням 4 видів фіксаторів колінного суглоба. Аналізували параметри двохопорного стояння на базометричній платформі: розподіл навантаження (%) від загальної маси тіла між нижніми кінцівками, коефіцієнт опороспроможності, зміщення загального центра тиску (ЦТ) у фронтальній і сагітальній площинах, ротацію ЦТ.Результати: у пацієнтів із ушкодженням ПСЗ виявлено достовірне превалювання розподілу маси тіла на інтактну нижню кінцівку порівняно з травмованою — (73,3 ± 2,8) і (26,7 ± 1,6) % відповідно; коефіцієнт опороспроможності дорівнював 0,36 ± 0,4; зміщення загального ЦТ у фронтальній площині — (11,5 ± 1,1) мм; у сагітальній — (7,2 ± 1,0) мм; кут ротації ЦТ — (7,8 ± 1,2)°. За умов застосування фіксаторів залежно від їх виду визначено тенденцію до зменшення асиметрії розподілу маси тіла пацієнта між кінцівками.Висновки: у результаті обстеження групи здорових волонтерів отримані основні показники двохопорного стояння на базометричній платформі. Аналіз базометричних показників пацієнтів із ушкодженням ПСЗ показав значне їх відхилення порівняно з групою волонтерів. Серед вивчених конструкцій фіксаторів колінного суглоба найбільш функціонально придатним виявився наколінник із двовісним шарніром. Він дає змогу максимально скоригувати і поліпшити біомеханічні показники статики й опороспроможність травмованої кінцівки

Study of degradation of photovoltaic cells based on A3B5 nanoheterostructures under ionizing radiation

Solar radiation is a practically inexhaustible and environmentally friendly source of energy. Solar panels are classified as devices very sensitive to radiation. Therefore, the problem of creating radiation-resistant solar panels is quite acute. In operation, solar batteries (SB) are exposed to hard corpuscular radiation (radiation belts, solar and cosmic radiation), resulting in the structure of accumulated violations leading to a gradual deterioration of their electrical characteristics. We have conducted experimental studies of single-degradation characteristics of solar cells (SE) based on GaAs with Ge substrate due to the structural damage produced by irradiation with fast neutrons and electrons and step-by-step irradiation with fast neutrons and electrons at different fluences. Before and after each set of neutron and electron fluence we have measured light current–voltage characteristics (CVC) and photosensitivity spectra of the AOC. We have determined the following parameters from the measured CVC: the fault current, the open circuit voltage, the maximum coefficient of performance (COP) (ratio of maximum power to the product of the flux density of solar energy and the cell area) and the fill factor (the ratio of maximum power to the product of the short-circuit current and voltage idling)