bluuebunny/crossref_metadata_2025 huggingface dataset:
Lactate Dehydrogenase Prior to Transarterial Hepatic Chemoperfusion Predicts Survival and Time to Progression in Patients with Uveal Melanoma Liver Metastases
Authors: Ludwig Johannes , Haubold Johannes , Heusner Till-Alexander , Bauer Sebastian , Siveke Jens T. , Richly Heike , Wetter Axel , Umutlu Lale , Theysohn Jens M.
Published: December 2020

Purpose To assess serum lactate dehydrogenase (LDH) as a pretreatment prognostic factor in patients with uveal melanoma liver metastases treated with transarterial hepatic chemoperfusion (THC).

Materials and Methods 56 patients (48 % male, median age: 63.5 years) underwent a median of 4 THC sessions. Kaplan-Meier for median overall survival (OS) and time to hepatic progression (TTP; 95 %CI) in months and Cox proportional hazards model for uni- (UVA) & multivariate analyses (MVA) for hazard ratio (HR) evaluation were calculated.

Results The median OS was 9.4 months. The pretreatment LDH value before 1st THC was the strongest OS predictor with 19.8 months for normal (≦ 280 units per liter (U/L)), 9.7 for intermediate (> 280–< 1000 U/L), and 3.84 months for high (≧ 1000 U/L) LDH. LDH significantly predicted a median TTP with 8 months, 4 months, and 1 month for normal, intermediate, and high LDH, respectively. UVA revealed intermediate (16.5) and high (77.3) LDH, bilirubin > the upper limit of normal (ULN) (2.89), alkaline phosphatase > 1.5 ULN (6.8), leukocytes > ULN (4.2), gamma-glutamyl transferase (GGT) > ULN (7), extrahepatic metastases (1.8) and liver lesions ≥ 5 cm (3.6) as significant predictors for worse OS. MVA confirmed intermediate (5) and high (27.1) LDH, bilirubin (5.7), GGT (2.9), and tumor size ≥ 5 cm (3.7) as significant independent predictors for worse OS. Patients with decreasing vs. increasing LDH > 10 % between 1st and 2nd THC (median: 38 days) survived longer (14.6 vs. 4.3 months) and progressed later (7 months vs. 1 month).

Conclusion Elevated pretreatment serum LDH is an essential and robust OS and TTP predictor, potentially allowing for the identification of patients benefiting most from transarterial hepatic chemoperfusion.

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Short-term Prophylaxis for Delivery in Pregnant Women with Hereditary Angioedema with Normal C1-Inhibitor
Authors: Moraes Caroline Guth de Freitas Batista de , Mikami Liya Regina , Ferrari Lilian Pereira , Pesquero João Bosco , Chong-Neto Herberto José , Rosario Filho Nelson Augusto
Published: December 2020

Objective To verify the efficacy of short-term prophylaxis for vaginal or cesarean section childbirth with plasma-derived C1-inhibitor concentrate in pregnant women. They should have hereditary angioedema (HAE) and normal plasma C1-inhibitor.

Methods Case report of pregnant women diagnosed with HAE with normal C1-inhibitor who had been treated with intravenous C1-inhibitor concentrate for prophylaxis of angioedema attacks when hospitalized for delivery. The exon 9 of the Factor 12 (F12) genotyping gene was performed by automatic sequencing in all patients.

Results Three cases of pregnant women with HAE with normal serum level of C1-inhibitor are reported. The genetic test detected the presence of a pathogenic mutation in the F12 gene. Deliveries occurred uneventfully and patients had no HAE symptoms in the following 72 hours.

Conclusion C1-inhibitor concentrate could be useful to prevent angioedema attacks during and after delivery.
Sociodemographic and Clinical-pathological Study of Molecular Subtitles of Breast Carcinoma in a Reference Unit of Maranhão
Authors: Reis Ana Paula Almeida Miranda , Teixeira Cecilma Miranda de Sousa , Medeiros Adriano Rêgo Lima de , Chaves Karlla Zolinda Cantão , Albuquerque Camila Rosa de , Melo Mateus Rufino
Published: December 2020

Objective To evaluate the distribution of the main sociodemographic and clinical-pathological characteristics in women with breast cancer according to the molecular profile by immunohistochemistry.

Methods A cross-sectional, retrospective, analytical and quantitative study was performed, with an analysis of 137 medical records from January 2015 to December 2018 of women attending the High Complexity in Oncology Unit of the city of Imperatriz, state of Maranhão, Brazil. The immunohistochemical profile of tumors based on the estrogen and progesterone receptor, Human Epidermal growth factor Receptor-type 2 (HER2) overexpression and Ki67 cell proliferation index was defined, from which six molecular subtypes were determined: luminal A, luminal B-HER2 negative, luminal B-HER2 positive, triple negative, overexpression of HER2 and inconclusive.

Results A total of 52.6% of the patients were postmenopausal, mean age 52.1 years old, brown (56.2%), had a schooling level < 9 years (40%), staging > IIB (52.6%) and 23.4% had metastasis. Invasive ductal carcinoma accounted for 84.7%, tumor size was 2 to 5 cm (48.9%), with lymph node involvement (56.2%), axillary lymphadenectomy in 67.2%, and mastectomy in 73.7% of the patients. The most frequent molecular subtype was the luminal B-HER2 negative (36.5%), and the luminal A subtype showed characteristics of better prognosis when compared with the others.

Conclusion It was concluded that in the association of molecular subtypes with sociodemographic and clinical-pathological characteristics, there were no statistically significant results obtained, except for complementary therapy, referring to hormone therapy, and there was a high index of metastasis at diagnosis, which was a worrying factor and indicative of failures in the screening and early diagnosis of this population.
Update on Thrombocytopenia in Pregnancy
Authors: Subtil Simone Filipa Carrasqueira , Mendes Jorge Miguel Bastos , Areia Ana Luísa Fialho de Amaral , Moura José Paulo Achando Silva
Published: December 2020

Thrombocytopenia, defined as platelet count < 150,000 mm3, is frequently diagnosed by obstetricians since this parameter is included in routine surveillance during pregnancy, with an incidence of between 7 and 12%. Therefore, decisions regarding subsequent examination and management are primordial. While most of the cases are due to physiological changes, as gestational thrombocytopenia, other causes can be related to severe conditions that can lead to fetal or maternal death. Differentiating these conditions might be challenging: they can be pregnancy-specific (pre-eclampsia/HELLP syndrome [hemolysis, elevated liver enzymes, low platelets]), or not (immune thrombocytopenia purpura, thrombotic thrombocytopenic purpura or hemolytic uremic syndrome). Understanding the mechanisms and recognition of symptoms and signs is essential to decide an adequate line of investigation. The severity of thrombocytopenia, its etiology and gestational age dictates different treatment regimens.
The birds and the Bedes: Race, gender, and sexuality in Bede’s In Cantica Canticorum
Authors: Wade Erik
Published: December 2020

This article argues that Bede – like modern intersectional analysis – believed that identity categories cannot be disentangled or understood in isolation. In Bede’s commentary on the Song of Songs, skin color, gender, and religious identity intermix with metaphors of sexuality. These categories coalesce in a monumental lesson on how to read. Bede claims that reading the Song literally – perceiving Black skin, eroticism, gender confusion – means reading like a Jew and prevents readers from seeing the feminine, metaphorical level below the masculine, carnal level. This article suggests that intersectional analysis is akin to much medieval thought rather than being an anachronistic imposition on a historical text. Intersectional analysis can lay bare how medieval theologians saw identity categories as interwoven and interdependent, even while the theologians themselves entrenched hierarchies of race, gender, sexuality, and religious difference. For Bede, Christian interpretation is a continual process of moving from a literal outside (Black, masculine, carnal, sexual) to a metaphorical inside (beautiful, feminine, allegorical, chaste, reproductive). Once inside, however, we – like the bird passing through the hall – must return once again to the outside in an endless movement between layers that echoes theological processes of rumination and blurs the divide between the contemplative and the active life.
Application of a drift compensation low-level radio frequency system based on time-multiplexing pick-up/reference signals
Authors: Lin Zhenyang , Du Yingchao , Huang Gang , Xu Yilun , Huang Wenhui , Tang Chuanxiang
Published: December 2020

The high accuracy, low drift low-level radio frequency (LLRF) system is essential for the long-term stability of the accelerator RF and the acquirement of low emittance, high intensity electron beams. A time-multiplexing pick-up/reference signal based LLRF system is proposed to deal with the component temperature related phase drift and has been deployed and applied at the Xi’an Gamma-ray Light Source (XGLS) injector. The long term dual-receiver out-of-loop stability experiments with a continuous wave laser based phase reference distribution system (PRDS) show that the LLRF system can achieve ∼40 fs Root-Mean-Square (rms) phase accuracy and 51 fs/52 fs peak–peak drift (in 7 days/17 h with the high power RF system, respectively) while the reference phase varies both ∼30 ps. An ∼4 h beam-based experiment has also been conducted to evaluate the overall performance of the whole XGLS timing and synchronization system, which shows that the PRDS, LLRF system, high power RF system, and laser oscillator laser-RF synchronization system can keep long-term phase stability.
Effects of electrode gap on radio-frequency discharge characteristics with a hollow electrode
Authors: He Liuliang , He Feng , Ouyang Jiting , Dou Wenna
Published: December 2020

In this paper, the effects of electrode gap on the discharge characteristics in low-pressure argon radio frequency (RF) discharge with a hollow electrode were investigated by a two-dimensional particle-in-cell/MCC model. The results show that the time-averaged electric field, electron density, sheath potential drop, and sheath thickness change with the increasing electrode gap. It is also found that the electron density varies non-monotonically with the electrode gap increasing from 4 to 12 mm due to the different intensities of the hollow cathode effect (HCE) and electron heating at different electrode gaps. The axial sheath at the bottom of the hollow electrode is found to determine the depth of the plasma in the hole and can significantly modulate the intensities of the HCE and electron heating. With the reducing electrode gap, the hole of the hollow electrode is eventually filled with the sheath, and the bulk plasma region is compressed. The results indicate that a small electrode gap is not beneficial to obtain large area plasma with high density outside the hole. Altering the electrode gap can tailor the spatial distribution of the plasma in the RF discharge with a hollow electrode and obtain an optimal electron density.
Theoretical investigations of structural, electronic, and physical properties of Rb2BX6 (B = Ti, Se, Pd; X = F, Cl, Br, I) double perovskites
Authors: Du Xue , He Dafang , Liu Yuqing , Cheng Nanpu
Published: December 2020

Using the density functional theory prediction, we investigate the structural, elastic, electronic, optical, and vibrational properties of B- and X-dependent double perovskites Rb2BCl6 (B = Ti, Se, Pd) and Rb2PdX6 (X = F, Cl, Br, I) in this work. They are indirect bandgap semiconductors. For Rb2BCl6, the top valence bands are dominated by Cl-3p states and the bottom conduction bands by Ti-4d/Se-5p/Pd-5d states. For Rb2PdX6, the top valance bands are formed by X-p (F-2p, Cl-3p, Br-4p, and I-5p) states, and the bottom conduction bands are mainly composed of Pd-5d states. The high values of imaginary dielectric functions, high absorption coefficients, and low reflection coefficients indicate that Rb2BCl6 (B = Ti, Se, Pd) and Rb2PdX6 (X = F, Cl, Br, I) double perovskites are potential lead-free photoelectric materials. In addition, Rb2PdX6 (X = Br, I) double perovskites have the potential to be used in photovoltaic applications as they have broad optical absorption in the visible light range and dynamic stability under 400 K. The lattice vibrations of Rb2PdF6, examined as an example, show that the high-frequency vibration modes (T1u, T2g, Eg, and A1g) are derived from PdF62− clusters, while the low-frequency vibration modes (T2g and T1u) are contributed by Rb atoms.
AlGaN-based deep ultraviolet light emitting diodes with magnesium delta-doped AlGaN last barrier
Authors: Wang Tien-Yu , Lai Wei-Chih , Sie Syuan-Yu , Chang Sheng-Po , Wu Yuh-Renn , Chiou Yu-Zung , Kuo Cheng-Huang , Sheu Jinn-Kong
Published: December 2020

A magnesium delta-doped AlGaN last barrier (MDDLB) was introduced in the structure of deep ultraviolet light emitting diodes (DUV LEDs) to improve their light output power. The MDDLB effectively improved hole injection efficiency and increased the hole concentration at the last AlGaN well of DUV LEDs. It also raised the potential barrier for electron transport from multiple quantum wells to the p-side. Therefore, it reduced overflow of electrons into the p-side of DUV LEDs. These phenomena improved light emitting efficiency of DUV LEDs with the MDDLB. In addition, the current crowding effect was suppressed by the MDDLB in DUV LEDs. Therefore, the 350 mA-light output power of DUV LEDs with the MDDLB was approximately 30% larger than that of DUV LEDs without the MDDLB. Furthermore, the largest light output power of DUV LEDs with the MDDLB was 55 mW, which was approximately 46% larger than that of DUV LEDs without the MDDLB. The suppressed current crowding effect by the MDDLB also reduced efficiency droops of DUV LEDs with the MDDLB. Therefore, efficiency droops of DUV LEDs decreased from 64% to 55% when the MDDLB was introduced.
Effective mass of heavy, light, and spin split-off band electron and hole g-factor in cubic perovskite materials
Authors: Ompong David , Inkoom Godfred , Singh Jai
Published: December 2020

Analytical expressions for the effective mass of heavy, light, and spin split-off electrons are obtained by diagonalizing the k⋅p Hamiltonian for cubic perovskite crystal structures and used to calculate these in nine perovskite materials. An expression for the effective hole g-factor is also derived and calculated in these perovskites. The calculated effective mass of heavy electrons ranges from 1.619 m0 to 0.201 m0, of light electrons from 0.357 m0 to 0.146 m0, and of spin split-off electrons from 0.584 m0 to 0.169 m0. It is found that Cl- and Pb-based perovskite materials have larger heavy, light, and spin split-off electron effective masses. It is also found that the effective g-factor increases with the atomic size, from Cl to I, for the series CsSnX3(X=Cl,Br,I).
Mapping the growth of p-type GaN layer under Ga-rich and N-rich conditions at low to high temperatures by plasma-assisted molecular beam epitaxy
Authors: Sadaf Sharif Md. , Tang Haipeng
Published: December 2020

We present a detailed study of Mg acceptor, p-type doping of GaN grown by plasma-assisted molecular beam epitaxy in both Ga-rich and N-rich conditions at low (∼580 °C) to high growth temperatures (∼740 °C). A growth map is constructed using results from a broad range of growth conditions, which shows the dependence of Mg incorporation and surface roughness on the III/V ratio and growth temperatures. Detailed secondary ion mass spectroscopy and atomic force microscopy studies confirmed that N-rich conditions are favorable for significantly higher Mg-incorporation efficiency (∼80%), whereas the Ga-rich growth condition is preferable for achieving a smooth surface morphology (root mean square roughness: ∼1–2 nm) with poor Mg incorporation. The room temperature Hall measurement confirms that the hole concentration in the range of ∼7 × 1017 to 2 × 1019 cm−3 can be achieved in Ga-rich and N-rich conditions, respectively, at a fixed Mg flux depending on the growth conditions. Our detailed study provides a proper guideline for realizing an efficient Mg-doped GaN layer and is applicable, in principle, to different nitride-based electronic and photonic devices.
Looped carbon nanotube fibers as cathodes with giant field enhancement factors
Authors: Dall'Agnol F. F. , de Assis T. A. , Fairchild S. B. , Ludwick J. , Tripathi G. , Cahay M.
Published: December 2020

Structures with a sharp apex amplify an applied macroscopic field, FM, substantially and generate significant field electron emission (FE). The apex barrier field, Fa, is related to FM by the apex field enhancement factor (aFEF), γa≡Fa/FM. In this Letter, we provide a theoretical explanation for extremely high-effective FEFs (104 ≲ γeff ≲ 105) recently extracted from an orthodoxy theory analysis of the emission current–voltage characteristics of looped carbon nanotube (CNT) fibers, making them promising candidates for FE applications. In this work, we found a dependence of γa on the geometrical parameters for an isolated conductive looped CNT fiber, modeled via the finite element technique. The aFEF of looped CNT fibers is found to scale as γa=2+[hf/rfiber][ln (2h/rfiber)]−1, where f≡1+θ[rfiber/b]α[ln (2h/rfiber)−1], in which h is the height of a looped fiber standing on an emitter plate, b is its base length, rfiber is the radius of the fiber, and θ and α are fitting parameters that have a nonlinear dependence on the scaling parameter h/b. Our results show that the scaling law predicts that 10  ≲ γa ≲ 100 for looped CNT fibers with parameters: 10 μm ≤rfiber≤ 100 μm, 0.4 ≤h/b≤ 2, and d/h≥1, where d is the distance between the apex of the looped fiber and the anode. However, scanning electron microscopy images reveal the presence of microfibrils protruding from the looped CNT fiber surface close to its apex. We show that the modeling of a combined two-stage structure (looped CNT fiber + fibrils) leads to aFEF values in excellent agreement with an orthodoxy theory analysis of FE experiments performed on these fibers.
Effects of surface morphological structure of a brown alga miyeok (Undaria pinnatifida) on sustainable drag reduction
Authors: Lee Sang Joon , Heo Seongkwang , Yoon Gun Young , Seo Eunseok , Choi Woorak
Published: December 2020

Liquid-infused surfaces are a promising passive technique for frictional drag reduction. However, their practical application is limited by the easy depletion of the lubricant infused in the surface by external forces. Miyeok contains mucus on its surface, which induces a sustainable slippery surface under flow conditions. In this study, the effect of the surface morphological structures of miyeok on slippery characteristics was examined. The surface of miyeok has bump-like microstructures and tiny pores of mucilage gland cells with a re-entrant inlet configuration. A replica model of the miyeok surface was fabricated by adopting a molding process using polydimethylsiloxane. The miyeok replica model was dipped into a silicone oil solution to obtain a slippery surface property. The surface structures of fresh miyeok and the replica were checked by comparing their scanning electron microscopy images. A replica of a kelp surface was also fabricated by employing the same method. The heights of the surface microstructures of the miyeok replica were more uniform than those of the kelp replica. The sustainable drag reduction effect of the replica models’ surfaces was assessed by a sessile drop method. The liquid-infused miyeok replica surface (LIMRS) showed better sustainability than other surfaces. The slippery properties of the LIMRS were examined by measuring slip length and pressure drop. The drag reduction rates measured by the two methods were approximately 24% and 19%. The present results would be helpful for understanding the effects of the surface structure of natural miyeok on sustainable drag reduction and developing a biomimetic sustainable drag-reducing surface.
High temperature metamaterial terahertz quantum detector
Authors: Jeannin Mathieu , Bonazzi Thomas , Gacemi Djamal , Vasanelli Angela , Suffit Stéphan , Li Lianhe , Davies Alexander Giles , Linfield Edmund , Sirtori Carlo , Todorov Yanko
Published: December 2020

We demonstrate a high-temperature performance quantum detector of Terahertz (THz) radiation based on three-dimensional metamaterial. The metamaterial unit cell consists of an inductor-capacitor (LC) resonator laterally coupled with antenna elements. The absorbing region, consisting of semiconductor quantum wells, is contained in the strongly ultra-subwavelength capacitors of the LC structure. The high radiation loss of the antenna allows strongly increased collection efficiency for the incident THz radiation, while the small effective volume of the LC resonator allows intense light-matter coupling with a reduced electrical area. As a result, our detectors operate at much higher temperatures than conventional quantum well detectors demonstrated so far.
Polarization spectroscopy for quantitative analysis of atmospheric CO2 and air plasma flows
Authors: Meindl A. , Loehle S. , Fasoulas S.
Published: December 2020

This article demonstrates the feasibility of polarization spectroscopy as a diagnostic tool for quantitative analysis of atmospheric pressure plasma conditions. Atmospheric pressure air and CO2 plasma flows created in a microwave-powered plasma torch are investigated. A detailed line-by-line simulation approach is employed to interpret the polarization spectra recorded in the resonator of the plasma torch. The line-by-line code for the simulation of polarization spectroscopy of O2 Schumann–Runge has been developed and verified with measurements in atmospheric pressure O2 plasma for a previous study. In this study, this simulation code for O2 absorption is used to model the polarization spectra measured in CO2 plasma and determine the inner energy distribution of the molecules for the first time. The resulting vibrational and rotational temperatures are Tvib=6115K and Trot=2660K. In order to simulate measurements in air plasma, the line-by-line code is extended to enable two-species modeling using O2 Schumann–Runge as well as NOγ absorption. The new two-species simulation approach allows for the determination of the relative number density nO2/nNO=1500±100. This paper clearly demonstrates the value of polarization spectroscopy as a quantitative measurement technique for atmospheric pressure plasma applications.
Experimental study on the trajectory of projectile water entry with asymmetric nose shape
Authors: Shi Yao , Hua Yang , Pan Guang
Published: December 2020

In this study, we investigated the water entry trajectory characteristics of a projectile with an asymmetric nose shape at different initial impact velocities and impact angles experimentally. With high speed photography, the water entry cavities and projectile motions were captured to obtain the trajectory curve and the attitude angle of the projectile. Compared to the projectile with a flat nose shape, the experimental results presented that the trajectory of the projectiles with asymmetrical nose shapes shows obvious deflection during the water entry process, and the deflection amplitude of the trajectory increases as the cut angle decreases under the same water entry conditions. It is found that the change trend of the projectile’s attitude angle is the almost same under different impact angle conditions. In addition, for the same type of asymmetric nose shape, the trajectory deflection increases with the increase in impact velocity. Finally, a theoretical model of the water entry trajectory was established to predict the projectile motion and trajectory of the projectile with an asymmetric nose shape before the tail-slap process. We compared the experimental data with the calculated results, and the theoretical calculation gave a good approximation with the experimental results. The maximum error of the displacements between the theoretical results and the experimental results is only 3.25%.
Orientation-dependent band offsets between (AlxGa1−x)2O3 and Ga2O3
Authors: Mu Sai , Peelaers H. , Zhang Y. , Wang M. , Van de Walle Chris G.
Published: December 2020

Band alignments between Al2O3 and Ga2O3 are investigated for four different orientations [(100), (010), (001), and (2¯01)] using density functional theory with a hybrid functional. By comparing with explicit interface calculations, we confirm that alignments can be reliably extracted from slab calculations that take atomic relaxation and strain into account. The presence of pseudomorphic strain shifts the average electrostatic potential as well as the band edges. Tensile strain in Al2O3 is found to lower the conduction band; the absolute deformation potential is calculated to be −9.5 eV for Al2O3 and −9.1 eV for Ga2O3. Our results show that the largest conduction-band offset will occur at a pseudomorphic (AlxGa1−x)2O3/Ga2O3 interface with the (100) orientation, allowing us to estimate the density of the two-dimensional electron gas in a modulation-doped field-effect transistor.
Talking about ‘victims’, ‘survivors’ and ‘battered women’: how labels affect the perception of women who have experienced intimate partner violence (‘Víctimas’, ‘supervivientes’ y ‘mujeres maltratadas’: cómo influyen las etiquetas en la percepción de las mujeres que han sufrido violencia por parte de sus parejas)
Authors: Romero-Sánchez Mónica , Skowronski Marika , Bohner Gerd , Megías Jesús L.
Published: December 2020

Two studies addressed effects of the labels ‘victim’, ‘battered woman’ and ‘survivor’ on the perception of women who have experienced intimate partner violence (IPV). Spanish undergraduates provided free associations (Study 1; N = 54) and completed semantic differentials (Study 2; N = 142) regarding the labels. Results showed that the term ‘survivor’ evoked more positive associations and ratings than both ‘victim’ and ‘battered woman’, which did not differ from each other. At the same time, however, when asked directly, participants rated ‘survivor’ as the least appropriate term. These seemingly opposing findings replicate research on the terms’ use in sexual aggression. Results were independent of individuals’ acceptance of myths about IPV or knowing a woman who has experienced IPV. Implications for the use of specific language when communicating about IPV are discussed.
People at risk of social exclusion: mental health, structural-economic factors and sociocultural factors (Personas en riesgo de exclusión social: salud mental, factores económico-estructurales y socio-culturales)
Authors: Villegas Crisstel , Ibabe Izaskun , Arnoso Ainara
Published: December 2020

The concept of social exclusion is complex, as it is a multidimensional and dynamic process. The objective of this study is to identify the clinical profile of people at risk of social exclusion, to analyse gender differences with respect to the Jehoel-Gijsbers and Vrooman model of social exclusion and to obtain a predictive model of mental health problems. To do so, the Instrument to Assess Social Exclusion of the Basque Social Services System was applied to a sample of 597 people at risk of social exclusion in the Basque Country. Regarding the results, 84% of the participants showed some signs of a more or less severe mental disorder. Females showed a better sociocultural situation than males, although their income level was lower. The predictive models of health problems, the sociocultural dimension and functional autonomy were the most salient factors. Mental health services should be integrated into psychosocial intervention programmes in order to provide comprehensive care and promote social inclusion.
Integrated Low Noise Amplifier with Capacitive Shunt Feedback Impedance Matching for Radio Astronomy
Authors: Bimana Abadahigwa , Sinha Saurabh
Published: December 2020

The noise performance of integrated low noise amplifiers (LNAs) is impaired by on-chip inductors owing to their low-quality factor, especially when inductors are used in the signal path at the input, such as for the inductively degenerated common-emitter amplifier. The inductively degenerated common-emitter configuration is largely used in LNA design, owing mainly to its ability to achieve impedance and noise matching simultaneously. This paper proposes an LNA configuration that achieves impedance matching and noise matching simultaneously without an inductor in the input signal path, owing to capacitive feedback and transistor sizing. Only the resistive component of the optimum noise resistance is matched to the source resistance. The impact of the mismatch due to the reactive component to the noise figure is reduced by the ratio G

s
/R

n
. A technique initially developed for the broadband matching of a single-layer microstrip patch antenna is used for the output matching network. Using a 130 nm silicon–germanium heterojunction bipolar transistor process, simulation results indicate a noise figure of 2.3 dB, a gain of 26 dB and S
11 and S
22 that are better than −12 dB at 1.42 GHz. This frequency corresponds to the 21 cm hydrogen line. This novel multi-stage LNA can be used for the detection of electromagnetic radiation from neutral hydrogen atoms from space in radio astronomy and the proposed design methodology can be generalized to LNAs.
Realizing high efficiency 532 nm laser by optimizing the mode- and impedance-matching
Authors: Yao Wenxiu , Wang Qingwei , Tian Long , Li Ruixin , Shi Shaoping , Wang Jinrong , Wang Yajun , Zheng Yaohui
Published: December 2020

Increasing the conversion efficiency of second harmonic generation (SHG) is an area of interest in research. We report a high-efficiency 532 nm laser generation, with a conversion efficiency of 94.04 ± 0.115% from the pump depletion of 98.1% ± 0.1%, by accurately quantifying the round-trip loss and the transmissivity of the input mirror using our proposed scheme. The optimal conversion efficiency of the cavity-enhanced frequency doubling process is independent of the waist and is determined by the pump depletion, round-trip loss, and transmissivity of the input mirror. These results show that the cavity-enhanced frequency doubling process is not necessary to set the focusing parameter at the optimal single-pass conversion. These results provide a guide for future research on high-efficiency SHG.
Universal statistics of Fisher information in deep neural networks: mean field approach*
Authors: Karakida Ryo , Akaho Shotaro , Amari Shun-ichi
Published: December 2020

The Fisher information matrix (FIM) is a fundamental quantity to represent the characteristics of a stochastic model, including deep neural networks (DNNs). The present study reveals novel statistics of FIM that are universal among a wide class of DNNs. To this end, we use random weights and large width limits, which enables us to utilize mean field theories. We investigate the asymptotic statistics of the FIM’s eigenvalues and reveal that most of them are close to zero while the maximum eigenvalue takes a huge value. Because the landscape of the parameter space is defined by the FIM, it is locally flat in most dimensions, but strongly distorted in others. Moreover, we demonstrate the potential usage of the derived statistics in learning strategies. First, small eigenvalues that induce flatness can be connected to a norm-based capacity measure of generalization ability. Second, the maximum eigenvalue that induces the distortion enables us to quantitatively estimate an appropriately sized learning rate for gradient methods to converge.
H2 controller design on engine rotor rotation
Authors: C A Ramírez V , Grisales-Noreña L F , Montoya O D
Published: December 2020

This article exposes the implementation of the H2 controller, which is rare in the literature because it is a more robust control and not only errors but also disturbances that can affect the dynamics of the control system are considered. The deduction of the equations for the continuous and discrete case is shown, which is little identified in this type of controllers and finally the implementation of said control over the rotation angle of the rotor of a motor is exposed, which is of great utility and importance. in electrical power systems for the generation and service of energy.
Problem of the P-Stockings applied to the location of facilities
Authors: Mesa F , Devia D , Ospina R
Published: December 2020

One of the problems derived from the overcrowding of cities and industry is the location of optimal facilities, these types of problems suffer from the problem of dimensionality themselves. In the following article, the problem is formulated in a mathematical way and it is approached from a metaheuristic epistemology which is the only methodology for now to find local optimum, since these optimization problems are still open in the scientific literature because they are considered problems of nondeterministic polynomial time. The explored technique is that of genetic algorithms which uses the classical theory of evolution to formulate and solve optimization problems.
Characterization of error sources in an inertial unit using Allan variance and nonlinear parameter adjustment
Authors: Hernandez W A , Castillo-Corredor J S , Ramos-Cifuentes J A , Fuentes F , Castañeda L F
Published: December 2020

Locating in space is essential for devices that perform navigation. currently inertial measurement units have been developed to allow navigation, however, this type of sensors present different errors in measurements. They have different errors that appear and accumulate when measurements advance. For this reason, the characterization of the error sources presented in sensor BNO055 is performed; data is acquired using a Raspberry Pi and Allan’s variance method was used for data analysis. A parameter fit is made in the error equation using the Levenberg-Marquardt numerical method a method commonly used in experimental physics.
Modeling of thermal and gas dynamic processes in additive shell and tube heat exchangers
Authors: Pugachuk A S , Fominyh N K , Gavrilova Yu A
Published: December 2020

As part of a gas microturbine engine development, a number of new heat exchanger flow channels, which are produced by using additive technologies, are considered. Geometric three-dimensional models of several heat exchanger elements (with internal, external and combined finning – 3 and 6 rows of ribs, spade spiral of three sizes) are created. Also a mathematical modeling of heat carriers in their flow channels is carried out, taking into account heat transfer through the walls. The analysis of calculated thermohydraulic parameters, namely the heat power and pressure losses, is realized. The spade shape of the heat exchanger element allows intensifying heat exchange (comparable to a 3-fin pipe). It has lower hydraulic resistance compared to 6-fin pipes. It has been found that the change in a standard size of spade spiral pipes does not affect their heat exchange characteristics. The disadvantage of pipes with internal fins is a rapid increase of hydraulic resistance during the operation due to a deposition of microturbine exhaust gases soot.
Tracer visualization of vortex breakdown patterns in confined and unconfined flows
Authors: Skripkin S G , Tsoy M A , Naumov I V
Published: December 2020

Current work deals with the study of swirling laminar flows in confined and unconfined flows in order to identify common patterns considering the phenomenon of vortex breakdown. Two types of vortex breakdown patterns are created: spiral and bubble. To catch the main flow features the modern tracer visualization technique adapted to experimental conditions is used. Measurements of velocity distributions are conducted via two-component LDA system. This work also confirms some ideas proposed by (Jones et al. 2015) about generalization of vortex breakdown conditions in different geometries.
Heat exchange in the back lip cavity of the large solid-propellant rocket motor
Authors: Benderskyi B Ya , Chernova A A
Published: December 2020

Issues of numerical modeling of spatial gas dynamics and heat exchange in the back lip cavity of the combustion chamber of a large solid-propellant rocket motor (SRM) are considered. Topological features of the flow structure and thermophysical parameters near the nozzle cap in the back lip cavity are analyzed. Distribution of the heat transfer coefficient over the nozzle bottom surface in the back lip cavity is obtained by the radial coordinate. The obtained dependences fairly correlate with the known experimental data.
Computational and experimental study of 3D flow near the cube immersed in the turbulent free convection boundary layer on a vertical heated plate
Authors: Chumakov Yu S , Levchenya A M , Smirnov E M
Published: December 2020

Results of a coordinated computational and experimental study of time-averaged velocity and temperature fields in the vicinity of an adiabatic cube that is inserted into the turbulent free convection vertical-plate boundary layer are presented. The numerical simulation was based on the steady-state RANS approach using the k-ω SST turbulence model and a version of the differential Reynolds stress model (DRSM). The hot-wire technique was used for velocity measurements, simultaneously with temperature measurements by an accompanied “cold” wire. Two turbulence models produced similar vortex flow structures near the obstacle; however some important quantitative distinctions were observed. The velocity value profiles predicted for the middle vertical plane showed generally a good accordance with the hot-wire measurements carried out in this plane, especially in the DRSM case.
Experimental and numerical study of gravitational sedimentation of the polydisperse water-in-oil emulsion
Authors: Valliullina V I , Mullayanov A I , Musin A A , Kireev V N , Kovaleva L A
Published: December 2020

Experimental and numerical studies of the process of gravitational deposition of a polydisperse water-in-oil emulsion are carried out. The dynamics of emulsion deposition is determined based on the results of digital image processing. Histograms of the size distribution of emulsion droplets at different sampling depths during deposition are obtained. A comparative analysis of numerical and experimental data is performed.
An experimental study of the integral characteristics of the intrachannel liquid film suction in a turbine stator blades cascade
Authors: Gribin V G , Tishchenko V A , Popov V V , Tishchenko A A , Gavrilov I Yu , Alekseev R A
Published: December 2020

This paper presents the results of an experimental study of the integral characteristics of the intrachannel liquid film suction in a flat cascade of turbine stator blades. Two slots for removing the liquid film from the interblade channel were arranged on the pressure surface of the stator blade. The experiments were carried out with initial steam wetness y
0 = 3 ÷ 9.5 % and theoretical Mach number downstream the cascade M
lt = 0.6 ÷ 0.78. The operation mode of the moisture removal system was determined by the relative pressure drop on the moisture-removing slots and varied over a wide range. The investigations were carried out for both the operation of the moisture-removing slots one at a time and the combined suction of the liquid film simultaneously through both slots. The measurement system used in the experiments allowed separately determining the mass flow rates of steam and liquid removed from the interblade channel. The obtained integral characteristics served to evaluate the influence of various factors on the efficiency of the intrachannel moisture removal system. Based on the analysis of the research results, recommendations on the design and operation of intrachannel moisture removal systems have been formulated.
Increasing the heat dissipation of an evaporator in the refrigeration system
Authors: Sazhin I A
Published: December 2020

The article considers the possibility of increasing the heat transfer of the evaporator of the refrigeration unit. The methods of Kutateladze-Sorokin, Baker, Baggs and Brill are used to diagnose the flow regimes of R-22, R-134a, R-600a refrigerants at gas contents from 0.7 to 0.95. The values of the Nusselt criterion, the heat transfer coefficient in the selected sections of the evaporator pipe are calculated. The results are consistent with known data. An example of changing the thickness of a liquid film of a refrigerant is considered to increase the heat transfer of the evaporator of a refrigeration unit.
Influence of the gravitational field variability on convective heat and mass transfer and on the free surface
Authors: Fedyushkin A I
Published: December 2020

The article is devoted to the influence of non-constancy of the earth’s gravitational field on fluid hydrodynamics and heat-mass transfer. The structure of convective fluid flow in a square cavity with lateral heated under constant and a variable on space gravity field. The changing diagonal symmetry of structure of convective flow and its effect on the distributions of temperature and concentration are considered. The results of modeling a problem of non-stationary flow of water with a free surface in a horizontal two-phase layer with an instantaneous change the acceleration of gravity from a constant g
0 to variable g(x) = g
0
x are presented. The nature of the wave change of the free surface of water with overturning, bursts of waves during intensive non-stationary flow in the horizontal layer caused by the changing of gravity from constant to variable is shown.
Thermal expansion of ice based gas hydrates
Authors: Belosludov V R , Zhdanov R K , Gets K V , Bozhko Y Y , Subbotin O S
Published: December 2020

This work aims at studying thermal expansion of ice Ih based gas hydrates that play important role in self-preservation effect of classical gas hydrates. Linear thermal expansion of ice Ih based hydrogen hydrates are calculated using a very effective statistical thermodynamic model of gas hydrates developed by the authors of this work. Molecular structures of all studied systems are obtained by MD simulations, and all parameters required by the model are obtained by using Quasiharmonic Lattice Dynamic approach. In accordance with our calculations, introduction of hydrogen into the system not only significantly affects the unit cell parameter of ice, but also increases linear thermal expansion and makes it comparable to the classical gas hydrates such as CH4, CO2, etc.
An experimental study of the evaporation rate of nanofluid droplets with SiO2 nanoparticles
Authors: Bochkareva E M , Miskiv N B , Nazarov A D , Terekhov V V , Terekhov V I
Published: December 2020

In this work, experimental data are presented on the evaporation rate of suspended droplets of distilled water and distilled water with the addition of nano particles of silicon dioxide during evaporation in an air stream with a low blowing rate. The measurements were carried out at Reynolds numbers calculated from the relative flow velocity Re <10. The evaporation rate of suspended droplets of distilled water and nanofluid was compared.
Experimental study of the motion and form of the vapor bubble floating in the annular channel at subatmospheric pressure
Authors: Dekhtyar R A , Ovchinnikov V V
Published: December 2020

An experimental study was made of the dynamics of a vapor bubble floating up in an annular channel at subatmospheric pressure. A vapor bubble was formed after boiling of an overheated degassed liquid in an annular channel formed by two tubes with diameter of 25 mm and 16 mm. The study shows that the dynamics of the vapor cavity during the ascent of vapor bubble in an annular channel has qualitative difference from the dynamics of gas bubble and has much in common with the dynamics of Taylor vapor bubble floating in a small round tube. One of the features of the behavior of the vapor cavity in the annular gap is that in the pulsation mode at the collapse stage, it can disintegrate into several parts.
Theoretical study of the self-preservation effect in CF4 gas hydrates
Authors: Zhdanov R K , Gets K V , Bozhko Y Y , Subbotin O S , Belosludov V R
Published: December 2020

This work studies thermodynamic properties of CF4 gas hydrates using the statistical thermodynamic model of inclusion compounds, developed in our laboratory and closely associated with Quasiharmonic Lattice Dynamic (QLD) and Molecular Dynamic Simulation (MD). Thermal expansion coefficient of CF4 gas hydrate is calculated at different hydrate composition. The thermal expansion coefficient is shown to be lesser than the thermal expansion coefficient of CH4 hydrates, but larger than ice Ih, that still indicates the presence of the self-preservation effect. The thermal expansion coefficient is very sensitive to the composition of the hydrate and can vary in a wide range. The same is true for the hydrate lattice parameter as well; it is shown that at certain conditions it may be even less than for hypothetical empty hydrate structure. The self-preservation effect may be applied for many aspects related to CF4 compound, especially for storage and transportation purposes in producing semiconductor electronics.
Influence of structural and phase composition on mechanical characteristics of laser welded joints of aluminium-lithium alloys
Authors: Malikov A G , Orishich A M
Published: December 2020

The paper presents the analysis of the structural and phase composition by the methods of electronic microscopy, X-ray diffraction analysis and synchrotronic radiation of the laser welded joints for the Al-Li alloys of the systems Al-Cu-Li and Al-Mg-Li without and after the post thermal treatment. It is shown that during the welding, strengthening phases dilute in the solid solution of the welded joint, and, in the case of Al-Cu-Li alloys, they concentrate over the dendrite boundary. The optimal post heat treatment restores the structural phase composition and mechanical properties of the weld.
The calculation of lean mixture burning in model combustors with flow swirling
Authors: Maiorova A I , Vasilyev A Yu , Sokolova E I
Published: December 2020

The testing of various turbulence models was conducted when calculating separated swirling flows. For burning simulation, a simple phenomenological model is presented. The model takes into account the gas swirling effect on the velocity of flame propagation. The developed technique is applied to the calculation of the burn-out of a lean mixture in model combustion chambers with three-tier swirlers. It is shown that the reversed organization of combustion with outside ignition is more efficient than the scheme with inside ignition. In the calculations, the mutual swirling of the flows behind the swirlers was varied and its effect on the burn-out rate of the mixture was considered.
Study on the pyrolysis of different coal in atmospheres of argon, carbon dioxide, and steam
Authors: Slyusarskiy K V , Kadchik D Yu , Asilbekov A K
Published: December 2020

The pyrolysis process is fundamental in many deep coal utilization technologies. The comparison of conversion of three different types of coal was carried out utilizing thermal analysis in the atmosphere of argon, carbon dioxide, and steam within the temperature range from ambient temperature to 1000°C. The anthracite, bituminous coal, and lignite of Siberian deposits were studied. It was found that within the temperature range of 20-700°C for bituminous coal and lignite, and within 20-800°C for anthracite, the differences between mass loss rate in inert medium and other studied samples were insignificant. While flue gases (from fossil fuels burnt with low excess air ratio) in general consist of carbon dioxide and steam. Thus, they could be used for the pyrolysis of studied fuels within the mentioned temperature ranges.