bluuebunny/crossref_metadata_2025 huggingface dataset:
Minimally Invasive Approaches to Anterior Skull Base Meningiomas
Authors: Seaman Scott C. , Ali Muhammad S. , Marincovich Anthony , Li Luyuan , Walsh Jarrett E. , Greenlee Jeremy D. W.
Published: December 2020

Objective Anterior skull base meningiomas include olfactory groove, planum sphenoidale, and tuberculum sellae lesions. Traditionally, standard craniotomy approaches have been used to access meningiomas in these locations. More recently, minimally invasive techniques including supraorbital and endonasal endoscopic approaches have gained favor; however there are limited published series comparing the use of these two techniques for these meningiomas. Using our patent database, we identified patients who underwent these two approaches, and conducted a retrospective chart review to compare outcomes between these two techniques.

Methods A total of 32 patients who underwent minimally invasive approaches were identified: 20 supraorbital and 11 endoscopic endonasal. Radiographic images, presenting complaints and outcomes, were analyzed retrospectively. The safety of each approach was evaluated.

Results The mean extent of resection through a supraorbital approach was significantly greater than that of the endoscopic endonasal approach, 88.1 vs. 57.9%, respectively (p = 0.016). Overall, preoperative visual acuity and anopsia deficits were more frequent in the endonasal group that persisted postoperatively (visual acuity: p = 0.004; anopsia: p = 0.011). No major complications including cerebrospinal fluid (CSF) leaks or wound-related complications were identified in the supraorbital craniotomy group, while the endonasal group had two CSF leaks requiring lumbar drain placement. Length of stay was shorter in the supraorbital group (3.4 vs. 6.1 days, p < 0.001).

Conclusion Anterior skull base meningiomas can be successfully managed by both supraorbital and endoscopic endonasal approaches. Both approaches provide excellent direct access to tumor in carefully selected patients and are safe and efficient, but patient factors and symptoms should dictate the approach selected.
Does the Head Position Affect Neonatal Lateral Ventricular Volume?
Authors: Roy Priyanka , Lo Marcus , Bhattacharya Soume , Eagleson Roy , Fenster Aaron , de Ribaupierre Sandrine
Published: December 2020

Objective This study aimed to determine whether there are differences in the lateral ventricular volumes, measured by three-dimensional ultrasound (3D US) depending on the posture of the neonate (right and left lateral decubitus).

Study Design This was a prospective analysis of the lateral ventricular volumes of preterm neonates recruited from Victoria Hospital, London, Ontario (June 2018–November 2019). A total of 24 premature neonates were recruited. The first cohort of 18 unstable premature neonates were imaged with 3D US in their current sides providing 15 right-sided and 16 left-sided 3D US images. The neonates in the second cohort of six relatively stable infants were imaged after positioning in each lateral decubitus position for 30 minutes, resulting in 40 3D US images obtained from 20 posture change sessions. The images were segmented and the ventricle volumes in each lateral posture were compared with determine whether the posture of the head influenced the volume of the upper and lower ventricle.

Results For the first cohort who did not have their posture changed, the mean of the right and left ventricle volumes were 23.81 ± 15.51 and 21.61 ± 16.19 cm3, respectively, for the 15 images obtained in a right lateral posture and 13.96 ± 8.69 and 14.92 ± 8.77 cm3, respectively, for the 16 images obtained in the left lateral posture. Similarly, for the second cohort who had their posture changed, the mean of right and left ventricle volumes were 20.92 ± 17.3 and 32.74 ± 32.33 cm3, respectively, after 30 minutes in the right lateral posture, and 21.25 ± 18.4 and 32.65 ± 31.58 cm3, respectively, after 30 minutes in the left lateral posture. Our results failed to show a statistically significant difference in ventricular volumes dependence on posture.

Conclusion Head positioned to any lateral side for 30 minutes does not have any effect on the lateral ventricular volumes of neonates.

Key Points
Cavitation induced shear and circumferential stresses on blood vessel walls during photo-mediated ultrasound therapy
Authors: Singh Rohit , Wang Xueding , Yang Xinmai
Published: December 2020

Photo-mediated ultrasound therapy (PUT) is a novel technique using combined laser and ultrasound to generate enhanced cavitation activity inside blood vessels. The stresses produced by oscillating bubbles during PUT are believed to be responsible for the induced bio-effects in blood vessels. However, the magnitudes of these stresses are unclear. In this study, a two-dimensional axisymmetric finite element method-based numerical model was developed to investigate the oscillating bubble-produced shear and circumferential stresses during PUT. The results showed that increased stresses on the vessel wall were produced during PUT as compared with ultrasound-alone. For a 50-nm radius bubble in a 50-μm radius blood vessel, the produced circumferential and shear stresses were in the range of 100 kPa–400 kPa and 10 Pa–100 Pa, respectively, during PUT with the ultrasound frequency of 1 MHz, ultrasound amplitude of 1400 kPa–1550 kPa, and laser fluence of 20 mJ/cm2, whereas the circumferential and shear stresses produced with ultrasound-alone were less than 2 kPa and 1 Pa, respectively, using the same ultrasound parameters. In addition, the produced stresses increased when the ultrasound pressure and laser fluence were increased but decreased when the ultrasound frequency and vessel size were increased. For bubbles with a radius larger than 100 nm, however, the stresses produced during PUT were similar to those produced during ultrasound-alone, indicating the effect of the laser was only significant for small bubbles.
Observation of interacting polaronic gas behavior in Ta-doped TiO2 thin films via terahertz time-domain spectroscopy
Authors: Cheng Liang , Sarkar Tarapada , Lourembam James , Tutchton Roxanne , Motapathula M. , Zhao Daming , Zhu Jian-Xin , Venkatesan Thirumalai , Chia Elbert E. M.
Published: December 2020

Transparent conductive oxides (TCOs)—materials that have the twin desirable features of high optical transmission and electrical conductivity—play an increasingly significant role in the fields of photovoltaics and information technology. As an excellent TCO, Ta-doped anatase TiO2 shows great promise for a wide range of applications. Here, terahertz time-domain spectroscopy is used to study the complex optical conductivity σ̃ω of the TCO—heavily Ta-doped TiO2 thin films with different Ta-doping concentrations, in the frequency range of 0.3–2.7 THz and the temperature range of 10–300 K. Fitting the complex optical conductivity to a Drude-like behavior allows us to extract the temperature dependence of the effective mass, which suggests the existence of many-body large polarons. Moreover, the carrier scattering rate of Ta-doped TiO2 with different carrier concentrations agrees with the interacting polaron gas theory. Our results suggest that with increasing electron density in TiO2, the interaction between polarons is larger and electron–phonon coupling is smaller, which is beneficial for achieving high mobility and conductivity in TiO2.
High yield uniformity in pseudo-vertical diamond Schottky barrier diodes fabricated on half-inch single-crystal wafers
Authors: Hanada Takanori , Ohmagari Shinya , Kaneko Junichi H. , Umezawa Hitoshi
Published: December 2020

We fabricated diamond pseudo-vertical Schottky barrier diodes using a half-inch semi-insulative diamond (100) wafer. Most diodes exhibited a large rectifying ratio (>1010) with undetectable leakage current at a reverse bias of 5 V (0.6 MV cm−1), with only 2% of diodes exhibiting an Ohmic-like leakage current. Surface defects were observed under the Schottky barrier diode, and their impacts on electrical properties were analyzed using a Murphy model and correlation factor analysis. We found that most crystalline defects (surface hillocks) were electrically non-active and that non-epitaxial crystallites and process-related field-plate cracks were the main defects that induced a large leakage current. Schottky barrier diodes without such killer defects showed a high electric field strength of ∼5 MV cm−1.
Normalized intrinsic emittance of cold emission cathodes
Authors: Voin Miron , Schächter Levi
Published: December 2020

We determine the normalized intrinsic emittance associated with a cold emission cathode. While, in principle, we are primarily motivated by carbon nanotube (CNT) cathodes, our approach is applicable to any type of cold cathode. Its essence relies on the evaluation of the initial momentum as the particles tunnel through the Schottky–Nordheim barrier based on the spectral radiance function. Next, the momentum distribution is integrated over the geometry, providing, along with well-known Fowler–Nordheim current, an integral expression for the emittance. An analytic approximation solution shows that the normalized emittance of a single emitter is proportional to the normalized Fermi velocity βF=vF/c of the emitter material, transverse dimension of the emitter, and the square root of the applied local electric field. In the case of an array of such emitters, dependency on the latter virtually vanishes. According to our theoretical results and based on experimental data for CNT emitters available in the literature, we predict that practical cold emission cathodes may provide a normalized intrinsic emittance comparable or even superior to that of conventional photo-emission cathodes used in state-of-the-art electron sources.
Liquid-metal capillary switch for electrical power application
Authors: Zhu Xiaonan , Yang Fei , Zhao Siyuan , Wang Haoran , Niu Chunping , Rong Mingzhe
Published: December 2020

Liquid-metal (LM) electrical switches have been desired for decades to overcome intrinsic shortcomings of traditional mechanical switches equipped with solid contacts. Existing LM electrical switches, functioning via solid-liquid wetting or liquid droplet actuation, mostly focus on low current and small signal switches. In this Letter, a LM switch aiming at a power-level current switch has been proposed. A proof-of-concept prototype was fabricated via encapsulating Galinstan droplets into a silicone matrix. The device switches on a circuit when LM droplets are squeezed into a capillary channel to coalesce. The switch-off process with arc burning is realized by capillary breakup of the LM bridge and high-speed contact separation driven by a pressure difference contributed by Laplace pressure, electrical arc pressure, and atmospheric pressure. Switching off 0.5 A–5 A current under DC 220 V within 0.13–1.69 ms, the device demonstrates a high-speed current interruption ability compared to two kinds of commercial push-button switches. A high-speed camera is utilized to visualize the LM switch's current interruption process. In such a situation, the LM contacts exhibit a separation speed up to 3.85 m/s. Apart from the pressure difference, a slip layer between the LM and capillary wall also plays an important role in driving LM contacts. The LM switch has potential for applications in communication and control equipment acquiring a fast switch of the electrical power signal. This paper offers a framework for designing the LM switch dealing with intense electrical discharge.
Exact description of excitonic dynamics in molecular aggregates weakly driven by light
Authors: Janković Veljko , Mančal Tomáš
Published: December 2020

We present a rigorous theoretical description of excitonic dynamics in molecular light-harvesting aggregates photoexcited by weak-intensity radiation of arbitrary properties. While the interaction with light is included up to the second order, the treatment of the excitation–environment coupling is exact and results in an exact expression for the reduced excitonic density matrix that is manifestly related to the spectroscopic picture of the photoexcitation process. This expression takes fully into account the environmental reorganization processes triggered by the two interactions with light. This is particularly important for slow environments and/or strong excitation–environment coupling. Within the exponential decomposition scheme, we demonstrate how our result can be recast as the hierarchy of equations of motion (HEOM) that explicitly and consistently includes the photoexcitation step. We analytically describe the environmental reorganization dynamics triggered by a delta-like excitation of a single chromophore and demonstrate how our HEOM, in appropriate limits, reduces to the Redfield equations comprising a pulsed photoexcitation and the nonequilibrium Förster theory. We also discuss the relation of our formalism to the combined Born–Markov–HEOM approaches in the case of excitation by thermal light.
Characterization of an RF-driven argon plasma at atmospheric pressure using broadband absorption and optical emission spectroscopy
Authors: Nayak G. , Simeni Simeni M. , Rosato J. , Sadeghi N. , Bruggeman P. J.
Published: December 2020

Atmospheric pressure plasmas in argon are of particular interest due to the production of highly excited and reactive species enabling numerous plasma-aided applications. In this contribution, we report on absolute optical emission and absorption spectroscopy of a radio frequency (RF) driven capacitively coupled argon glow discharge operated in a parallel-plate configuration. This enabled the study of all key parameters including electron density and temperature, gas temperature, and absolute densities of atoms in highly electronically excited states. Space and time-averaged electron density and temperature were determined from the measurement of the absolute intensity of the electron-atom bremsstrahlung in the visible range. Considering the non-Maxwellian electron energy distribution function, an electron temperature (Te) of 2.1 eV and an electron density (ne) of 1.1×1019m−3 were obtained. The time-averaged and spatially resolved absolute densities of atoms in the metastable (1s5 and 1s3) and resonant (1s4 and 1s2) states of argon in the pure Ar and Ar/He mixture were obtained by broadband absorption spectroscopy. The 1s5 metastable atoms had the largest density near the sheath region with a maximum value of 8×1017m−3, while all other 1s states had densities of at most 2×1017m−3. The dominant production and loss mechanisms of these atoms were discussed, in particular, the role of radiation trapping. We conclude with comparison of the plasma properties of the argon RF glow discharges with the more common He equivalent and highlight their differences.
Hybrid continuum-molecular modeling of fluid slip flow
Authors: Shaat Mohamed
Published: December 2020

Experiments on fluid systems in micro-/nano-scale solid conveyors have shown a violation of the no-slip assumption that has been adopted by the classical fluid mechanics. To correct this mechanics for the fluid slip, various approaches have been proposed to determine the slip boundary conditions. However, these approaches have revealed contradictory results for a variety of systems, and a debate on the mechanisms and the conditions of the fluid slip/no-slip past solid surfaces is sustained for a long time. In this paper, we establish the hybrid continuum-molecular modeling (HCMM) as a general approach of modeling the fluid slip flow under the influence of excess fluid–solid molecular interactions. This modeling approach postulates that fluids flow over solid surfaces with/without slip depending on the difference between the applied impulse on the fluid and a drag due to the excess fluid–solid molecular interactions. In the HCMM, the Navier–Stokes equations are corrected for the excess fluid–solid interactions. Measures of the fluid–solid interactions are incorporated into the fluid’s viscosity. We demonstrate that the correction of the fluid mechanics by the slip boundary conditions is not an accurate approach, as the fluid–solid interactions would impact the fluid internally. To show the effectiveness of the proposed HCMM, it is implemented for the water flow in nanotubes. The HCMM is validated by an extensive comparison with over 90 cases of experiments and molecular dynamics simulations of different fluid systems. We foresee that the HCMM of the fluid slip flow will find many important implementations in fluid mechanics.
Clitic pronouns in Archaic Chinese
Authors: Djamouri Redouane , Paul Waltraud
Published: December 2020

This article provides evidence for the so far neglected existence of two clitic pronouns, yǐ
以 and yǔ
與, in Archaic Chinese (10th c. – 3rd c. BC) in immediately
verb-adjacent position: ‘yǐ/yǔ-V’. While yǔ only encodes the comitative/associative, yǐ encodes all kinds of (argument and adjunct) roles, depending on the semantics of the verb involved. We argue that the clitic pronouns
yǐ and yǔ can neither be analysed as stranded prepositions left behind after extraction
of their complement (as, e.g., in English) nor as orphan prepositions, i.e., PPs with an in situ null
pronoun as complement (as, e.g., in French). This ties in with the general ban against prepositions lacking an overt complement, observed
throughout the history of Chinese.
Optical conductivity of triple point fermions
Authors: Habibi Alireza , Farajollahpour Tohid , Jafari S A
Published: December 2020

As a low-energy effective theory on non-symmorphic lattices, we consider a generic triple point fermion Hamiltonian, which is parameterized by an angular parameter λ. We find strong λ dependence in both Drude and interband optical absorption of these systems. The deviation of the T
2 coefficient of the Drude weight from Dirac/Weyl fermions can be used as a quick way to optically distinguish the triple point degeneracies from the Dirac/Weyl degeneracies. At the particular λ = π/6 point, we find that the ‘helicity’ reversal optical transition matrix element is identically zero. Nevertheless, deviating from this point, the helicity reversal emerges as an absorption channel.
Temperature response of laser heated emissive probe materials under vacuum and free atmospheric conditions
Authors: Kanik Abha , Sarma Arun , Ghosh Joydeep , Elumalai Amarnath , Pandya Shwetang , Bhope Kedar , Manchanda Ranjana
Published: December 2020

Precise temporal and spatial knowledge of plasma potential has been a challenging task for decades. Gradient in values of plasma potential govern local electric fields providing insight into many other bulk plasma properties like particle drifts, confinement, transport barriers etc and plays a crucial role in determining stability of magnetically confined high temperature plasmas. In high temperature devices like tokamaks, plasma tends to develop edge bifurcations and results in edge transport barriers, which are a key tool for enhancing the plasma conﬁnement properties in magnetic fusion devices, which in turn requires knowledge of plasma potential. Conventional emissive probes (CEPs) in high temperature magnetically confined plasmas are not advisable owing to their inherent properties and tokamak parameters like high magnetic field, ultra-high vacuum pressure etc as well as tokamak geometry. A new type of emissive probe is becoming popular in recent times in such devices called the laser heated emissive probe (LHEP). Mostly, LaB6 and graphite are used as a LHEP tip owing to their inherent properties of thermal conductivity, low work function, high emissivity, higher lifetime etc. Similar with LaB6 in its mechanical and electrical properties, CeB6 is emerging as a promising candidate for LHEP. CeB6 is a better electron emitter than graphite and LaB6 at comparatively low power due to its lower work function. In this work, the heating dynamics of LaB6 and CeB6 heated by a CW CO2 laser with maximum power of 55 W have been reported. Theoretical and simulation models using Matlab and ANSYS have been developed to understand and explain the temperature gaining process of the probes. Simulation results are further validated by comparing them with experimentally measured data using an infrared camera.
Structural health monitoring system of construction facilities: enhanced training approach
Authors: Kats V
Published: December 2020

Structural health monitoring (SHM) of constructions under operating conditions becomes a relevant problem. When dealing with this problem the specific nature and environment conditions of the controlled facility should be considered. Therefore it is very important to continuously train the monitoring system with new data acquired from sensors. Current paper presents an approach of considering training the SHM system as training of defect evolution detection model. This method consists of four subsequent stages which allows to build and train defect evolution detection model on the acoustic emission sensor data. It includes data preparation stages (feature extraction, feature selection), outlier detection and training stage via proposed modification of the One-Class SVM anomaly detection method. Proposed approach was verified on real fuel and energy infrastructure facility. Obtained results give good grounds for utilizing the suggested approach in SHM systems with acoustic emission sensors allowing detection evolutionary defects in controlled facility which contributes to prevention of emergency situations that may have economic, social and ecological consequences.
Categorization of process names
Authors: Kholmatova Zamira
Published: December 2020

The categorization of processes according to their functionality is a key point to understand, how the user spent his or her time working with a computer. This task is not trivial due to the limited textual information available with applications. The existing approaches of this area commonly use predefined categories or clusterization techniques for applications, not processes. These techniques also do not describe the choice of these particular categories. In this paper, we describe our approach for the categorization of process names and explain, why we choose the set of categories we used. We evaluated the proposed approach on our collected data and got 81% correctly classified processes.
Data federation through on-demand queries in intelligent transport systems
Authors: Golovnin O K
Published: December 2020

The paper proposes a federated approach to data integration in intelligent transport systems when data are requested from various sources using the on-demand query technique rather than traditional approach when data are accumulated in a single storage. The proposed approach is designed to reduce the number of data manipulations, thereby increasing the processing speed and reducing the necessary computing resources. The study was carried out on synthetically generated data: 10 data sources are used; each of them consists of 650000 records. Data federation reduces the memory used by an average of 53%, while the time of virtual federal database creation is on average 71% less than the traditional integration approach implementation. The approach to data federation is designed for implementation in intelligent transport systems of a new generation, where it is required to process large amounts of data coming from various heterogeneous sources.
Au Nanoparticle Sub-Monolayers Buried between Magnetron Oxide Thin Layers
Authors: Kondrateva A , Enns Y , Komarevtsev I , Kudryashov D , Mishin M
Published: December 2020

In this work, a versatile method to increase the optical response of the oxide nanostructures is proposed. It combines a magnetron deposition of oxide matrix with the thermal deposition and aggregation of metallic nanoparticles, allowing the preparation of wide band gap oxide heterostructures with buried plasmonic Au nanoparticles. Thin layers of Si/TiO2 and Si/NiO were deposited by reactive magnetron sputtering in a 2D nanostructure, followed by 2.5 nm gold layer thermal deposition and in N2 thermal annealing at 550 °C to induce the growth of the Au nanoparticles. Then Si/TiO2/AuNP and Si/NiO/AuNP were covered with TiO2 and NiO respectively. The reflectance maximum of the LSPR band appeared at around 700 ÷ 720 nm for both heterostructures. It was demonstrated that both Si/TiO2/AuNP/TiO2 and Si/NiO/AuNP/NiO heterostructures can enhance optical response in comparison with Si/TiO2 and Si/NiO. The results obtained indicate a broad prospect of using the formed structures in the field of integrated optoelectronic devices.
Preparation of Si substrates for monolithic integration of III−V quantum dots by selective MBE growth
Authors: Fominykh N A , Sobolev M S , Ilkiv I V , Mokhov D V , Berezovskaya T N , Bouravleuv A D
Published: December 2020

A new method for nanopit formation by molecular-beam epitaxy (MBE) on different silicon substrates has been investigated. The dependence of the shape and depth of the nanopits on substrate orientation and doping type has been studied. The samples with an array of nanopits with 25 nm depth and (2-6)·108 cm−2 density for subsequent monolithic selective growth of quantum dots (QD) have been created.
1 µm range InGaPAs three-dimensional islands grown by molecular beam epitaxy
Authors: Andryushkin V V , Gladyshev A G , Babichev A V , Kolodeznyi E S , Novikov I I , Karachinsky L Ya , Nevedomskii V N , Egorov A Yu
Published: December 2020

A new technique allowing growing three-dimensional InGaPAs islands with reduced surface density by molecular beam epitaxy is proposed. The structural and optical properties of the islands have been studied depending on the InGaP layer thickness, the substrate temperature, and exposure time in the arsenic flow. The estimated island density was about 1.3 · 1010 cm−2.
Raman and AFM studies of epitaxial graphene intended for manufacturing of transistors
Authors: Eliseyev I A , Babichev A V , Lebedev S P , Dementev P A , Zubov A V , Lebedev A A , Davydov V Yu
Published: December 2020

Graphene is considered as a promising material for electronic applications. In this work, micro-Raman spectroscopy, atomic force microscopy and Kelvin-probe force microscopy are used to study three epitaxial graphene samples: two commercially-available ones and one grown using a home-made setup. The obtained data indicates significant differences in homogeneity of strain and doping level, concentration of bilayer inclusions, surface topography and surface potential. Analysis of the measurements data allows us to establish connections between the topography of the samples and their structural properties. The results of these studies will help to understand the characteristics of transistors that are to be made on the basis of the studied samples.
Aluminum nanoparticles synthesis in spark discharge for ultraviolet plasmonics
Authors: Borisov V I , Lizunova A A , Mazharenko A K , Malo D , Ramanenka A A , Shuklov I A , Ivanov V V
Published: December 2020

In this paper, we demonstrate an ability to produce aerosol metal Al nanoparticles with plasmon resonance in the ultraviolet region in a spark discharge generator in pure argon atmosphere. The sizes of the obtained primary particles with metal Al core and natural oxide shell in the range from 4 to 50 nm, which were collected in agglomerates with mean size from 190 to 260 nm, were observed. Simulation extinction spectra according to Mi theory for obtained particle ensembles were calculated. It was experimentally and theoretically found that obtained nanoparticles ensembles demonstrate the broad extinction peaks with maximum below 250 nm depending on the synthesis conditions.
Growth technology and characterization of bulk crystalline gallium oxide
Authors: Panov D I , Spiridonov V A , Zakgeim D A , Kremleva A V , Bauman D A , Romanov A E , Bougrov V E
Published: December 2020

In this paper, we study the process of growth from the melt by Chokhralsky method of bulk β-Ga2O3 crystals. The effect of different configurations of growth zones and ambient composition on resulting bulk crystal quality has been evaluated. It is shown that the vertical gradient has a great influence on the quality of the growing crystal and the stability of growth. The optical properties of obtained β-Ga2O3 crystals were investigated. The crystallographic orientation of crystal faces and the structural quality of the samples were studied with the use of XRD.
Application of carbon nanoscale materials in instrument structures sensitive to the gas atmosphere
Authors: Morozova J V , Rezvan A A , Klimin V S
Published: December 2020

This paper presents a study of a vacuum gauge with a sensitive element based on an array of carbon nanotubes. In the course of the study, a plasma chemical vapor deposition method was used, which allows one to obtain oriented CNT arrays on various substrates. A feature of this method is the use of catalytic centers. A model for calculating the parameters of the formed emission structure is constructed. The corresponding current-voltage characteristics are built. The results obtained during the study show that the vacuum gauge has a sensitivity of the order of 2.4·10−8 A/Pa, a speed of 4 seconds, at U = 20 V, and an energy consumption of 1.5 · 10−7 W.
Formation of carbon nanoscale elements of vacuum microelectronics by plasma treatment of SiC
Authors: Rezvan A A , Kots I N , Tominov R V , Klimin V S , Ageev O A
Published: December 2020

The use of focused ion beams and atomic plasma chemical etching for forming an array of field emission structures on surface of SiC substrates is considered. SF6 was used as the fluorine-containing gas. Topology of formed elements was monitored using scanning electron microscopy method at Nova NanoLab 600. Dependences of geometric parameters of formed structures (topology of tip and its depth) on emission current were determined. Dependence of change in applied voltage and generated electric field of used to study probe on emission current density is also considered.
Photoluminescence of n-InP (100) surface passivated with aqueous Na2S solution
Authors: Serov Y M , Lebedev M V , Rakhimova O V , Lvova T V , Sedova I V
Published: December 2020

Passivation of the n-InP(100) surface with an aqueous solution of sodium sulphide (Na2S) has been investigated by spectroscopic photoluminescence (PL). After sulphide treatment the PL signal intensity of InP increased significantly and this increase is dependent on duration of sulphide passivation. The correlation of the increase in the PL intensity after sulphide treatment with the variation of the solution pH in contact with InP(100) surface has been established, that expect the possibility for optimization of the passivation process by monitoring the change of the solution pH value in the course of sulphide treatment of the semiconductor.
The influence of the temperature and Ti and TiN sublayer material on carbon nanotubes growth
Authors: Rudyk N N , Il’in O I , Il’ina M V , Osotova O I , Fedotov A A
Published: December 2020

The influence of the temperature and Ti and TiN sublayer material on the height, diameter, density, and uniformity of carbon nanotubes (CNTs) growth is studied. It was found that on the TiN sublayer, CNTs form an array with a more uniform diameter distribution of CNTs than on the Ti sublayer (minimum dispersion 5.6 nm versus 8.1 nm). It is shown that for the Ti sublayer, with an increase in the growth temperature, an almost linear increase in the CNT height occurs. It was found that an increase in the CNT height is accompanied by a decrease in their diameter for both sublayers. For a given thickness of Ni, arrays with a density of 3–18 μm−2 were obtained on the Ti sublayer, and on a TiN sublayer in the range of 8–21 μm−2. The greatest uniformity of the surface distribution of CNTs is showed at 660 °C. CNT arrays on the Ti sublayer are characterized by a lower concentration of bundles than on the Ti sublayer.
Atomic layer deposition of Ruthenium on different interfaces for an advanced metallization system of ICs
Authors: Smirnova E A , Miakonkikh A V , Rogozhin A E , Rudenko K V
Published: December 2020

Nucleation effects were experimentally studied for ruthenium thin films grown by plasma-enhanced atomic layer deposition (PEALD) using O2 plasma. Bis(ethylcyclopentadienyl)ruthenium (II) (Ru(EtCp)2) was used as Ru precursor. The films with the thickness 10 nm on different underlying thin layers (interfaces), including Si, SiO2, Ta2O5, TiN, and TaN were deposited to investigate the effects of interfaces for nucleation of the Ru in ALD process. Some of the samples were previously processed in ammonia and oxygen plasma to enhance nucleation. The processes of forming barrier layers based on titanium and tantalum nitrides by plasma-enhanced atomic layer deposition were also studied. Films properties were evaluated by spectral ellipsometry, scanning electron microscopy and atomic force microscopy.
Wet chemical etching of GaN or InGaN nanowires on Si substrate for micro and nano-devises fabrication
Authors: Lendyashova V V , Kotlyar K P , Reznik R R , Berezovskaya T N , Nikitina E V , Soshnikov I P , Cirlin G E
Published: December 2020

In this work, it is experimentally shown that the etching of GaN or InGaN NWs in the KOH solution allows managing the morphology and optical properties of the nanowires array. Thinning rate of GaN nanowires is 5 times slower than the rate for InGaN nanowires along semi-polar and non-polar direction for nanowires with Ga-polar crystal structure. The diameter of the InGaN NWs decreases from 200-100 to 30-40 nm. After etching process, the intensity photoluminescence (PL) of nanowires and uniformity PL signal at all sample area increase.
Analysis of methodological errors in measuring a digital automated bio-impedance meter
Authors: Antipenko V V , Pecherskaya E A , Zinchenko T O , Melnikov O A , Fimin A V , Zaryvahina S A
Published: December 2020

The development of medical technology is an integral component of preserving the future generations health, which consists of the prevention and early diseases diagnosis using modern diagnostic measuring instruments. One such instrument is a bio-impedance analyzer (BIA). This article presents the results of modeling and metrological analysis of the BIA electrical circuit, which allowed to minimize the main relative error to 0.1%.
The study of the properties of chitosan-based composite films filled with single-walled carbon nanotubes (SWCNTs) and treated with cold atmospheric plasma
Authors: Kolbe K A , Kamalov A M , Feklistov E G , Smirnova N V , Kodolova-Chukhontseva V V , Dresvyanina E N , Dobrovolskaya I P , Vaganov G V , Yudin V E
Published: December 2020

In the work composite films based on chitosan and single-walled carbon nanotubes (0.01%, 0.1%, 0.5% and 1%) were obtained. The electrical and mechanical properties of the composite films were measured. It was shown that a film with 1% SWCNT has sufficient electrical conductivity and optimal mechanical properties for the bioactivity of a culture of human dermal fibroblasts. It has been established that treating a film in a corona discharge changes the structure of the film and increases the adhesion and proliferation of human dermal fibroblast cells.
Fluorescent Ag-Nanoclusters for Evaluation of Serum Albumin and Immunoglobulin Content in Protein Mixtures
Authors: Mizincev A V , Sych T S , Polyanichko A M , Plotnikova L V , Garifullin A D , Voloshin S V , Kononov A I
Published: December 2020

In this work we designed, synthesized and characterized luminescent metal nanoclusters (NCs) on human serum albumin (HSA) and immunoglobulins (Ig). We demonstrate that the approach developed allows one to determine the relative content of albumins and immunoglobulins in biologically relevant protein mixtures based on the luminescent properties of the NCs. Fast and inexpensive approach which allows to determine concentrations of immunoglobulins (Ig) and serum albumin (HSA) in blood serum might be useful in clinical diagnostics.
Multimodal approach to reveal the effect of light irradiation on chemical composition of lipofuscin granules of human RPE tissues
Authors: Aybush Arseny V , Gulin Alexander A , Vasin Alexander A , Dontsov Alexander E , Nadtochenko Victor A , Ostrovsky Mikhail A
Published: December 2020

The accumulation of lipofuscin (LF) in tissues is considered as one a hallmark of the aging process. Usually formed in yellow-brown pigment aggregates or granules primarily composed of lipid residues and proteins, the exact chemical composition of LF varies among tissues. LF of the retinal pigment epithelium (RPE) is known to contain byproducts of the visual cycle, including one of the fluorophores in LF bis-retinoid N-retinyl-N-retinylidene ethanolamine (A2E). The last is characterized by high photoreactivity and implicates in age-related macular degeneration. Photoinduced production of reactive oxygen species (ROS) is shown among the main modes of A2E toxicity although particular photochemistry of A2E have yet to be completely identified. In this work we study changes in chemical composition of LF granules of human RPE under light irradiation using vibrational spectroscopy (femtosecond broadband CARS) and mass-spectrometry (TOF-SIMS) approach accompanied by measurements of fluorescence properties of the LF.
Using wavelet transform to detect peaks in PCR signals
Authors: Batov Y V , Puzko D A , Petrov A I , Davydov V V , Glinushkin A P
Published: December 2020

The article of the feasibility of determining the nucleotide sequence of sequencing to Sanger is justified. The signals from a sample obtained using a DNA analyzer in which there is a nucleotide sequence are reviewed. A method for determining the sequence based on a continuous wavelet transform is proposed. The results of experimental investigations are presented.
Passive mode-locking of p-doped quantum dot semiconductor lasers
Authors: Auth D , Korenev V V , Savelyev A V , Maximov M V , Zhukov A E , Breuer S
Published: December 2020

Quantum dot based monolithic edge-emitting semiconductor lasers at 1.25 µm are ideal sources for the generation of broad optical frequency combs for optical communication applications. In this work, InAs/InGaAs quantum dot lasers with different total laser length to absorber length ratio and with different p-doping concentrations in the GaAs barrier sections are investigated experimentally in dependence on the gain injection current and absorber reverse bias voltage. A smaller mode-locking area is found for the p-doped device in dependence on the laser biasing conditions. For the undoped active region 1.3 ps short pulse widths at a pulse repetition rate of 20 GHz with a pulse-to-pulse timing jitter of 111 fs are reported for an absorber section length of 12% to the total cavity length. For an undoped and p-doped device short pulse emission between 2.5 ps and 5.5 ps is attained and a shorter absorber section length of 8% or 5%.
Temperature dependence of I-V characteristics in p-Si/MoOx and n-Si/LiF/Ta selective contacts
Authors: Maksimova A A , Baranov I A , Kudryashov A D , Gudovskikh A S
Published: December 2020

The temperature dependences of I–V characteristics of structures with selective contacts based on molybdenum oxide and lithium fluoride were explored. p-Si/MoOx and n-Si/LiF/Ta model symmetrical structures were made. It was shown that the operating current decreasing with temperature decreasing to the one of liquid nitrogen.
Changing of the dynamic characteristics of the spectral components of the InGaN-based LEDs spectrum during current tests
Authors: Frolov I V , Radaev O A , Sergeev V A
Published: December 2020

The results of the study of changes in the dynamic characteristics of various spectral components of the full electroluminescence spectrum of green LEDs based on InGaN during tests with a pulsed current of increased density are presented. It was found that there is a decrease in the radiation power of the LED after 200 hours, as well as a decrease in the frequency of modulation of electroluminescence by 3 dB. It was found that a frequency change of 3 dB in the short-wavelength components of the spectrum is much larger than the long-wavelength ones. The results obtained indicate that the process of defect formation during testing proceeds more intensively in areas of a heterostructure with a low In concentration.
The study of voltage loss reasons in GaAs solar cells with embedded InGaAs quantum dots
Authors: Salii R A , Evstropov V V , Mintairov S A , Mintairov M A , Nakhimovich M V , Shvarts M Z , Kalyuzhnyy N A
Published: December 2020

In the work the effect of the number of In0.8Ga0.2As stacked quantum dots (QDs) embedded in a single-junction GaAs solar cell (SC) on its photoelectric characteristics has been studied. A series of GaAs SC structures, which differed by a number of embedded QD layers, were grown using metalorganic vapor phase epitaxy. By analyzing the electroluminescence spectra and the current–voltage characteristics of the obtained structures the main reason for the voltage loss in SC with QDs has been established which is an increase in recombination through the QD levels with an increase the number of QD layers.
Application of selective contacts for study of silicon surface degradation
Authors: Kudryashov D A , Maksimova A A , Baranov A I , Uvarov A V , Morozov I A , Gudovskikh A S
Published: December 2020

In this work an application of selective contacts p-Si/MoOx for evaluation of silicon surface degradation is shown. Using a method of I-V measurements the effect of silicon surface degradation during SiO2 magnetron deposition was demonstrated.
Lateral mode behaviour in diode lasers based on coupled ridges
Authors: Epanchinova A A , Payusov A S , Kornyshov G O , Serin A A , Kulagina M M , Zhukov A E , Gordeev N Yu , Maximov M V
Published: December 2020

We present a study of diode lasers with two identical optically coupled ridges. Two coupled ridges were made gradually divergent to a distance of 50 μm which allowed creating three electrically isolated sections within a single laser. We carried out numerical simulations of the electromagnetic modes in the coupled ridge waveguide and calculated far-field patterns for each mode. The results are in good agreement with the experimental data. We have found that current spreading provided unwanted optical gain in the active region in between ridges and dramatically changed the structure of the lasing modes. The obtained numerical and experimental results can be used to design twin-ridge diode lasers able to operate in mode-locking regimes.
A polarization-independent highly sensitive hybrid plasmonic waveguide structure
Authors: Butt M A , Fomchenkov S A
Published: December 2020

In this paper, we proposed a novel design of a polarization-independent hybrid plasmonic waveguide. The transverse magnetic (TM) hybrid mode is confined in the low index material sandwiched between the silicon core and top gold layer whereas the transverse electric (TE) hybrid mode is supported in a narrow air gap on both sides between the silicon core and a gold layer. For sensing applications, two vital parameters such as the sensitivity of the hybrid mode (S

mode
) and evanescent field ratio (EFR) are studied which depends on the geometric parameters of the waveguide. The geometric parameters of the waveguide are optimized using the finite element method. The highest S

mode
and EFR for both polarizations is greater than 0.91 and 0.6, respectively. This study shows that polarization-independent highly sensitive refractive index sensors or evanescent field absorption gas sensors can be realized by utilizing the proposed hybrid plasmonic waveguide design.
Radially Polarized Beams Forming Using Phase-Compensated Sectorial Dichroic Plates
Authors: Degtyarev S A , Karpeev S V , Fomchenkov S A
Published: December 2020

We propose to create radially polarized beam using 8-sectorial polarizer. The manufacturing technology of such elements is based on axially symmetric discretization of the required polarization and phase distributions. This representation leads to optical elements in the form of sector plates Simulation is provided with Comsol multiphysics software. We show that the plate can create the radially polarized beam with the vortex phase.
Manufacture of optical ceramics based on two solid solutions of the AgBr – (TlBr0.46I0.54) system
Authors: Zhukova L V , Lvov A E , Salimgareev D D , Yuzhakova A A , Belousov D A , Korsakov M S
Published: December 2020

This work is devoted to the synthesis and the optical properties study of a new multicomponent heterophase ceramic based on two solid solutions of the AgBr – (TlBr0.46I0.54) system. Ceramics are transparent in the infrared range from 1.0 to 40.0 ÷ 50.0 μm, non-hygroscopic, are photo- and radiation-resistant, flexible, as a result of which various optical products are made from it by hot embossing.
Performance of an optical non-volatile Ge2Sb2Te5-based storage element
Authors: Makarov M , Sapegin A , Barabanenkov M , Italyantsev A
Published: December 2020

Considerable growth in data exchange leads to enhanced requirements for computing, storage, and transmitting devices. Promising solutions to this challenge can be found in the use of phase-change materials. This paper is devoted to evaluating the frequency response of a non-volatile storage element with optical recording and readout. The evaluation shows that it is possible to reduce the device’s operating cycle time and improve its performance.
The Simulation of Gold Nanoparticle in a TiO2 Matrix Absorption and Reflection Spectra
Authors: Enns Y , Kondrateva A , Mishin M
Published: December 2020

In this work results of a nanocomposite structures optical parameters modelling are presented. The variable parameters were: shape of nanoinclusions, matrix width and incident radiation angle. The quasiperiodic nanocomposite structures consisting of a titanium dioxide matrix and gold nanoparticles were simulated. A spectral analysis of these structures showed the nonlinear nature of the absorption and reflection spectra and influence of the nanoparticles shape on it.
Effect of tin doping on optical properties of ZnO thin films grown on glass substrate
Authors: Volkova M G , Storozhenko V Yu , Petrov V V , Bayan E M
Published: December 2020

The optical properties of synthesized zinc oxide films doped with tin in different concentrations (0-5 mol.%) were studied. X-ray diffraction revealed that the main phase of the obtained films is ZnO (wurzite). According to SEM data, the film consists of nanocrystallites, which are 10-20 nm in size. It was shown that the introduction of 0.5 mol.% tin ions leads to an increasing in the absorption of wavelengths (in the range of 300-370 nm) and a slight narrowing of the band gap.
Study of silicon nitride O-ring resonator for gas-sensing applications
Authors: Elmanova A , An P , Kovalyuk V , Golikov A , Elmanov I , Goltsman G
Published: December 2020

In this work, we experimentally studied the influence of different gaseous surroundings on silicon nitride O-ring resonator transmission. We compared the obtained results with numerical calculations and theoretical analysis and found a good agreement between them. Our results have a great potential for gas sensing applications, where a compact footprint and high efficiency are desired simultaneously.
Experimental new ultra-high-speed all-optical coherent streak-camera
Authors: Bagayev S N , Averchenko V A , Chekhonin I A , Chekhonin M A , Balmaev I M , Mekhov I B
Published: December 2020

We have experimentally studied for the first time a new operation principle of the all-optical coherent streak-camera (Rabi deflector). In the experiment, we observed an effect of significant dynamical angular deflection of a pulse of semiconductor laser during the resonant pumping of the D2 line (780.24 nm) of 87Rb vapor in the range of diffraction angles ϕ = ± 5.45°. We propose to use the Rabi deflector as an energy efficient shaper of classical and single-photon wave packets. We analyze a possibility of the Rabi deflector operation in quantum systems with feedback.