bluuebunny/crossref_metadata_2025 huggingface dataset:
Porphyrin-based systems containing polyaromatic fragments: decoupling the synergistic effects in aromatic-porphyrin-fullerene systems
Authors: Ferrero Sergio , Barbero Héctor , Miguel Daniel , García-Rodríguez Raúl , Álvarez Celedonio M.
Published: October 2020

Designed molecule for decoupling the synergistic supramolecular effects in aromatic-porphyrin-fullerene host–guest systems.
Resonance-assisted/impaired anion–π interaction: towards the design of novel anion receptors
Authors: Du Juan , Wang Changwei , Yin Shiwei , Wang Wenliang , Mo Yirong
Published: October 2020

Substituents alter the electron density distribution in benzene in various ways, depending on their electron withdrawing and donating capabilities, as summarized by the empirical Hammett equation.
Correction: Individual control of singlet lifetime and triplet yield in halogen-substituted coumarin derivatives
Authors: Oberhofer Katrin E. , Musheghyan Mikayel , Wegscheider Sebastian , Wörle Martin , Iglev Eleonora D. , Nikolova Rositca D. , Kienberger Reinhard , Petkov Petko St. , Iglev Hristo
Published: October 2020

Correction for ‘Individual control of singlet lifetime and triplet yield in halogen-substituted coumarin derivatives’ by Katrin E. Oberhofer et al., RSC Adv., 2020, 10, 27096–27102, DOI: 10.1039/D0RA05737A.
Tuning fullerene miscibility with porphyrin-terminated P3HTs in bulk heterojunction blends
Authors: Seibers Zach D. , Collier Graham S. , Hopkins Benjamin W. , Boone Evan S. , Le Thinh P. , Gomez Enrique D. , Kilbey S. Michael
Published: October 2020

Porphyrin-terminated P3HTs represent an example of molecular engineering, where π-stacking interactions with the porphyrin enhance fullerene miscibility in BHJ blends.
Destabilization of LiBH4 by the infusion of Bi2X3 (X = S, Se, Te): an in situ TEM investigation
Authors: Pal Pratibha , Kumari Pooja , Wang Yongming , Isobe Shigehito , Kumar Manoj , Ichikawa Takayuki , Jain Ankur
Published: October 2020

The addition of chalcogenides destabilized LiBH4 efficiently and the lowest onset temperature was found to be 75 °C for LiBH4–50 wt% bulk Bi2S3. The detailed mechanism associated with this destabilization is proposed herein.
Efficient photocatalytic CO2 reduction mediated by transitional metal borides: metal site-dependent activity and selectivity
Authors: Shi Li , Wang Pei , Wang Qi , Ren Xiaohui , Ichihara Fumihiko , Zhou Wei , Zhang Hongwei , Izumi Yasuo , Cao Ben , Wang Shengyao , Chen Hao , Ye Jinhua
Published: October 2020

Transitional metal borides Ni3B, Co3B and Fe2B can serve as effective and low-cost cocatalysts to boost photocatalytic CO2 reduction performances.
Unveiling interfacial dynamics and structural degradation of solid electrolytes in a seawater battery system
Authors: Lee Chanhee , Wi Tae-Ung , Go Wooseok , Rahman Muhammad Fahmi , McDowell Matthew T. , Kim Youngsik , Lee Hyun-Wook
Published: October 2020

The interfacial dynamics of the NASICON solid electrolyte/aqueous media/catalysts can provide insights into the stability of the solid electrolyte via investigation of different current densities and pH values.
N-Doped carbon coating enhances the bifunctional oxygen reaction activity of CoFe nanoparticles for a highly stable Zn–air battery
Authors: Liu Qi , Liu Xu , Xie Ying , Sun Fanfei , Liang Zhijian , Wang Lei , Fu Honggang
Published: October 2020

3D nanosheets consisting of N-doped carbon conglutinated CoFe alloy nanoparticles have been constructed, in which the N-doped carbon can enhance the bifunctional oxygen reaction for a high-performance Zn–air battery.
Two-phase anion exchange synthesis: multiple passivation for highly efficient and stable CsPbCl3 nanocrystals
Authors: Lv Wenzhen , Xu Mingchuan , Ge Lei , Zhu Xun , Hong Junxian , Huang Wei , Chen Runfeng
Published: October 2020

Through Two-phase anion exchange method, CsPbCl3 NCs is prepared with well-maintained cube morphology and high photoluminescence quantum yields of about 95%.
Secure and communications‐efficient collaborative prognosis
Authors: Dhada Maharshi , Jain Amit Kumar , Herrera Manuel , Perez Hernandez Marco , Parlikad Ajith Kumar
Published: October 2020

Collaborative prognosis is a technique that is used to enable assets to improve their ability to predict failures by learning from the failures of similar other assets. This is typically made possible by enabling the assets to communicate with each other. The key enabler of current collaborative prognosis techniques is that they require assets to share their sensor data and failure information between each other, which might be a major constraint due to commercial sensitivities, especially when the assets belong to different companies. This study uses federated learning to address this issue and examines whether this technique will enable collaborative prognosis while ensuring sensitive operational data is not shared between organisational boundaries. An example implementation is demonstrated for the prognosis of a simulated turbofan fleet, where federated averaging algorithm is used as an alternative for the data exchange step. Its performance is compared with a conventional collaborative prognosis that involves failure data exchange. The results confirm that federated averaging retains the performance of conventional collaborative prognosis while eliminating the exchange of failure data within assets. This removes a critical hindrance in industrial adoption of collaborative prognosis, thus enhancing the potential of predictive maintenance.
Helios spacecraft data revisited: detection of cometary meteoroid trails by following in situ dust impacts
Authors: Krüger Harald , Strub Peter , Sommer Max , Altobelli Nicolas , Kimura Hiroshi , Lohse Ann-Kathrin , Grün Eberhard , Srama Ralf
Published: October 2020

Context. Cometary meteoroid trails exist in the vicinity of comets, forming a fine structure of the interplanetary dust cloud. The trails consist predominantly of the largest cometary particles (with sizes of approximately 0.1 mm–1 cm), which are ejected at low speeds and remain very close to the comet orbit for several revolutions around the Sun. In the 1970s, two Helios spacecraft were launched towards the inner Solar System. The spacecraft were equipped with in situ dust sensors which measured the distribution of interplanetary dust in the inner Solar System for the first time. Recently, when re-analysing the Helios data, a clustering of seven impacts was found, detected by Helios in a very narrow region of space at a true anomaly angle of 135 ± 1°, which the authors considered as potential cometary trail particles. However, at the time, this hypothesis could not be studied further.

Aims. We re-analyse these candidate cometary trail particles in the Helios dust data to investigate the possibility that some or all of them indeed originate from cometary trails and we constrain their source comets.

Methods. The Interplanetary Meteoroid Environment for eXploration (IMEX) dust streams in space model is a new and recently published universal model for cometary meteoroid streams in the inner Solar System. We use IMEX to study the traverses of cometary trails made by Helios.

Results. During ten revolutions around the Sun, the Helios spacecraft intersected 13 cometary trails. For the majority of these traverses the predicted dust fluxes are very low. In the narrow region of space where Helios detected the candidate dust particles, the spacecraft repeatedly traversed the trails of comets 45P/Honda-Mrkos-Pajdušáková and 72P/Denning-Fujikawa with relatively high predicted dust fluxes. The analysis of the detection times and particle impact directions shows that four detected particles are compatible with an origin from these two comets. By combining measurements and simulations we find a dust spatial density in these trails of approximately 10−8–10−7 m−3.

Conclusions. The identification of potential cometary trail particles in the Helios data greatly benefited from the clustering of trail traverses in a rather narrow region of space. The in situ detection and analysis of meteoroid trail particles which can be traced back to their source bodies by spacecraft-based dust analysers provides a new opportunity for remote compositional analysis of comets and asteroids without the necessity to fly a spacecraft to or even land on those celestial bodies. This provides new science opportunities for future missions like DESTINY+ (Demonstration and Experiment of Space Technology for INterplanetary voYage with Phaethon fLyby and dUst Science), Europa Clipper, and the Interstellar Mapping and Acceleration Probe.
An observational argument against accretion in magnetars
Authors: Doroshenko V. , Santangelo A. , Suleimanov V. F. , Tsygankov S. S.
Published: October 2020

The phenomenology of anomalous X-ray pulsars is usually interpreted within the paradigm of very highly magnetized neutron stars, also known as magnetars. According to this paradigm, the persistent emission of anomalous X-ray pulsars (AXPs) is powered by the decay of the magnetic field. However, an alternative scenario in which the persistent emission is explained through accretion is also discussed in literature. In particular, AXP 4U 0142+61 has been suggested to be either an accreting neutron star or a white dwarf. Here, we rule out this scenario based on the observed X-ray variability properties of the source. We directly compare the observed power spectra of 4U 0142+61 and of two other magnetars, 1RXS J170849.0−400910 and 1E 1841−045 with that of the X-ray pulsar 1A 0535+262, and of the intermediate polar GK Persei. In addition, we include a bright young radio pulsar PSR B1509-58 for comparison. We show that, unlike accreting sources, no aperiodic variability within the expected frequency range is observed in the power density spectrum of the magnetars and the radio pulsar. Considering that strong variability is an established feature of all accreting systems from young stellar objects to super-massive black holes and the absence of the variability reports from other magnetars, we conclude that our results also indicate that magnetars, in general, are not powered by accretion.
Walnut diversity and breeding in Kyrgyzstan
Authors: Mamadzhanov Davlet , Kenzhebaev Sovet
Published: October 2020

The article provides information about the form diversity and selection of walnuts in the natural walnut forests of Kyrgyzstan. In walnutfruit forests, there is a wide variety of forms of walnut and other wild fruit species. The species and intraspecific diversity of wild fruit trees and shrubs allows selecting the best forms for creating highly productive plantations in various forest conditions in order to obtain high yields of nuts and other fruits. Methods of selection and criteria for selecting the best forms of walnuts are described.
Influence of sucrose concentration in the culture medium on the condition of the photosynthetic apparatus of grapes cultured in vitro
Authors: Sundyreva Maria , Rebrov Anton , Mishko Alisa
Published: October 2020

An influence of different sucrose concentrations in the culture media on the photosynthetic parameters, photosynthetic apparatus related genes expression, oxidative processes and acclimation of grape plants cultured in vitro was examined in this article. An increase of the sucrose concentration in the culture media resulted in a reduced expression of several photosynthetic genes. The most effective functioning of the photosynthetic apparatus was discovered by a decreased amount of surcose in culture media. An increase of the sucrose concentration in the culture media disrupts pigments synthesis, particularly carotenoids, which can be a cause of the secondary oxidative stress formation and grape plants growth reduction during acclimation.
Effect of environmental conditions and genotype on nectar secretion in sunflower (Helianthus annuusL.)
Authors: Chabert Stan , Sénéchal Christopher , Fougeroux André , Pousse Jérémy , Richard Fabien , Nozières Emma , Geist Olivier , Guillemard Vincent , Leylavergne Solenne , Malard Constance , Benoist Alexandre , Carré Gabriel , Caumes Édith , Cenier Charlotte , Treil Alain , Danflous Sébastien , Vaissière Bernard E.
Published: October 2020

The sunflower crop provides an important honey flow for beekeepers. In France, beekeepers observed a decrease in honey yield from this crop these past years compared to the 1980s–1990s. They suspect the new cultivars to be less productive in nectar compared to the older ones, but no data is available to support this, and it is known that climate conditions have a strong impact on nectar secretion. This study aimed to explore the effect of abiotic environmental conditions on nectar secretion in sunflower, as well the range of variation of this secretion in a sample of current cultivars. Thirty-four current sunflower hybrid cultivars were sampled in test plots for their nectar secretion under varying conditions of temperature, air humidity and soil moisture. Air humidity controlled the sugar concentration of nectar, and thus its volume. To study nectar secretion independently from this effect, analyses subsequently focused on nectar sugar mass per floret. The nectar sugar mass increased with temperature up to an optimum of 32 °C, while the variation range of soil water tension was not sufficient to detect an effect on nectar sugar mass. This varied by up to 100% among the 34 cultivars (from 101 to 216 μg sugar per staminate floret in average), with a similar range to those reported in the literature for older cultivars. Likewise, oleic cultivars, a new type introduced since the early 2000s, were found to secrete the same amounts of nectar as linoleic cultivars, an older conventional type. The more self-fertile cultivars also showed no reduction in nectar secretion. Finally, we tested the method that measures the nectar gross secretion rate in one hybrid, and we observed that this hybrid secreted in average 28 μg sugar per hour per staminate floret. The potential benefits of this method were discussed.
The Electron Proton Helium INstrument as an example for a Space Weather Radiation Instrument
Authors: Kühl Patrick , Heber Bernd , Gómez-Herrero Raúl , Malandraki Olga , Posner Arik , Sierks Holger
Published: October 2020

The near-Earth energetic particle environment has been monitored since the 1970’s. With the increasing importance of quantifying the radiation risk for, e.g. for the human exploration of the Moon and Mars, it is essential to continue and further improve these measurements. The Electron Proton Helium INstrument (EPHIN) on-board SOHO continually provides these data sets to the solar science and space weather communities since 1995. Here, we introduce the numerous data products developed over the years and present space weather related applications. Important design features that have led to EPHINs success as well as lessons learned and possible improvements to the instrument are also discussed with respect to the next generation of particle detectors.
How to Capture the Bleeding Phenotype in FXI-Deficient Patients
Authors: Bertaggia Calderara Debora , Zermatten Maxime G. , Aliotta Alessandro , Alberio Lorenzo
Published: October 2020

Factor XI (FXI) is a serine protease involved in the propagation phase of coagulation and in providing clot stability. Several mutations in the F11 gene lead to FXI deficiency, a rare mild bleeding disorder. Current laboratory methods are unable to assess bleeding risk in FXI-deficient patients, because the degree of bleeding tendency does not correlate with plasma FXI activity as measured by routine coagulometric aPTT–based assays. Bleeding manifestations are highly variable among FXI-deficient patients and FXI replacement therapy can be associated with an increased thrombotic risk. A correct evaluation of the patient hemostatic potential is crucial to prevent under- or overtreatment. In recent years, different research groups have investigated the use of global coagulation assays as alternative for studying the role of FXI in hemostasis and identifying the clinical phenotype of FXI deficiency. This brief review article summarizes the main features of coagulation factor XI and its deficiency and resumes the principle axes of research and methods used to investigate FXI functions.
Effects of a Multicomponent Herbal Extract on the Course of Subclinical Ketosis in Dairy Cows – a Blinded Placebo-controlled Field-study
Authors: Durrer Manuela , Mevissen Meike , Holinger Mirjam , Hamburger Matthias , Graf-Schiller Sandra , Mayer Philipp , Potterat Olivier , Bruckmaier Rupert , Walkenhorst Michael
Published: October 2020

A blinded placebo-controlled multi-center on-farm trial was conducted in dairy cows with subclinical ketosis to investigate effects of a multicomponent herbal extract. Blood ketone levels were measured weekly in early lactating cows from 16 Swiss herds. Cows were subclassified based on their initial blood-β-hydroxybutyrate levels (≥ 1.0 [KET-low, 84 cows] and > 1.2 mmol/L [KET-high, 39 cows]) and randomly distributed to 3 groups treated orally with herbal extract containing Camellia sinensis, Cichcorium intybus, Gentiana lutea, Glycyrrhiza glabra, Taraxacum officinale, Trigonella foenum-graecum, and Zingiber officinale, sodium propionate, or placebo twice a day for 5 days. Milk yield, milk acetone, blood-β-hydroxybutyrate, glucose, nonesterified fatty acids, gamma-glutamyl transferase, and glutamate dehydrogenase were analyzed over 2 wk. Linear mixed effect models were used for data analysis. No effects were found for nonesterifed fatty
acids, gamma-glutamyl transferase, and glucose. Significantly higher glutamate dehydrogenase (29.71 U/L) values were found in herbal extract-treated animals compared to sodium propionate on day 7 (22.33 U/L). By trend, higher blood-β-hydroxybutyrate levels (1.36 mmol/L) were found in the placebo group of KET-high-cows on day 14 compared to the sodium propionate group (0.91 mmol/L). Milk yields of all treatment groups increased. Milking time and treatment showed a significant interaction for milk acetone: sodium propionate led to an immediate decrease, whereas herbal extracts resulted in a milk acetone decrease from day 7 on, reaching significantly lower milk acetone on day 14 (3.17 mg/L) when compared to placebo (4.89 mg/L). In conclusion, herbal extracts and sodium propionate are both likely to improve subclinical ketosis in dairy cows, however, by different modes of action.
Evaluation of Ground Reaction Forces and Limb Symmetry Indices Using Ground Reaction Forces Collected with One or Two Plates in Dogs Exhibiting a Stifle Lameness
Authors: Pettit Elizabeth M. , Sandberg Gabriella S. , Volstad Nicola J. , Norton Megan M. , Budsberg Steven C.
Published: October 2020

Objective The aim of the study was to evaluate the efficiency and consistency in the collection of ground reaction forces using one or two force plates from dogs with stifle lameness.

Animals Twenty-two client-owned dogs with unilateral stifle lameness were used.

Methods In a prospective study design, data were collected at a single time point using both one- and two-plate collection methods. Ground reaction forces collected included peak vertical force, vertical impulse and associated symmetry indices. Additionally, time required to obtain valid trials and the total number of trials were also recorded for both one-plate and two-plate collections. Linear mixed models were used to analyse differences in peak vertical force, vertical impulse and symmetry indices between the collection methods. A paired-T test was used to compare trial number and time of trial collection. The significance threshold was p < 0.05.

Results It took significantly longer to collect valid trials using one-plate both in time (16.1 ± 8.0 minutes vs, 8.0 ± 4.3 minutes with two plates) and number of trials (33.8 ± 14.8 trials vs. 16.4 ± 8.8 trials with two plates) (p < 0.0001). There was no difference in peak vertical force or vertical impulse data between collection methods. Neither the peak vertical force symmetry indices nor the vertical impulse symmetry indices were significantly different between one- and two-plate collection techniques.

Conclusion The total time and number of trials needed to collect valid trials in dogs with stifle lameness were minimized through the use of two force plates. However, there was no significant difference in the ground reaction force or symmetry index values collected between the two systems.
Type 2 Endoleak Management
Authors: Chen James X. , Stavropoulos S. William
Published: October 2020

Type 2 endoleaks are the most common endoleak type following endovascular aneurysm repair. The natural history of these endoleaks can vary, with some demonstrating a self-limited or indolent course, while others can contribute to aneurysm sac enlargement and rupture. A variety of embolization techniques, including transarterial catheterization and direct sac puncture techniques, have been developed for the treatment of type 2 endoleaks. In this article, the authors review the indications, techniques, and outcomes of current treatment strategies for type 2 endoleaks.
Open Surgical Repair of Abdominal Aortic Aneurysms Maintains a Pivotal Role in the Endovascular Era
Authors: Blackstock Christopher D. , Jackson Benjamin M.
Published: October 2020

Since the advent of endovascular aortic repair (EVAR) nearly three decades ago, there has been a paradigm shift in the treatment of the abdominal aortic aneurysm (AAA) to favor EVAR due to its reduced operative mortality, less invasive nature, and faster recovery times. However, more recently there has been an accumulation of data from large meta-analyses and randomized clinical trials revealing that EVAR has no survival benefit after approximately 2 years and is associated with substantially higher rates of reintervention and aneurysm rupture in the long term. These findings call into question the durability of EVAR compared with open aortic repair and emphasize the need for surgeons to remain competent with open aortic surgery in the modern era. This article will provide comprehensive review of a large body of literature comparing endovascular repair to open aortic surgery for the management of AAAs, and it will offer an overview of the open surgical repair technique for AAAs.
Influence of Different Pigment Incorporation Methods on the Sorption and Solubility of Medical Silicones
Authors: Nobrega Adhara Smith , de Moraes Melo Neto Clóvis Lamartine , de Magalhães Bertoz André Pinheiro , de Melo Moreno André Luiz , Goiato Marcelo Coelho
Published: October 2020

Objective The aim of this study is to verify the influence of three pigment incorporation methods (conventional, mechanical, and industrial) on the sorption and solubility of the MDX4-4210 and A-2186 silicones.

Materials and Methods The groups formed were based on the silicones used (A-2186 and MDX4-4210), intrinsic pigments (pink, bronze, and black), and pigment incorporation methods (conventional, mechanical, and industrial). The dimensions of all samples were 45-mm diameter (ø) × 1-mm thickness. Readings were taken initially and after 1,008 hours of aging.

Statistical Analysis Three-way analysis of variance and the Tukey's test were performed (α = 0.05).

Results For sorption and solubility, there was no difference between the incorporation methods for the A-2186 silicone, regardless of the pigment used (p > 0.05). For pink MDX4-4210, the industrial and mechanical methods showed higher values of sorption compared with the conventional method (p < 0.05). For bronze MDX4-4210, the industrial method showed a higher sorption value compared with the conventional and mechanical methods (p < 0.05). For black MDX4-4210, there was no difference between incorporation methods based on sorption (p > 0.05). For pink MDX4-4210, the mechanical method showed a higher solubility value compared with the industrial and conventional methods (p < 0.05). For black MDX4-4210 and bronze MDX4-4210, there was no statistically significant difference between incorporation methods based on solubility (p > 0.05).

Conclusion Based on sorption and solubility, for the A-2186 silicone, the conventional, mechanical, and industrial methods of pigment incorporation were equivalent. For the MDX4-4210 silicone, its results of sorption and solubility were varied, and further studies are recommended.
Safety of Prescribing Statins in Childhood Dyslipidemia
Authors: Al-Alaili Mohammed Khaled , Abdi Abdikarim Mohamed , Basgut Bilgen
Published: October 2020

Hyperlipidemia is on the rise in pediatrics, leading to early coronary artery disease complications. Familial hypercholesterolemia is an important risk factor, with the homozygous subtype being more dangerous, yet less prevalent than the heterozygous subtype. Statins are shown to be an effective treatment in this population. This systematic review will emphasize the safety of such drug class in pediatrics, while taking into consideration the latest cholesterol guideline. Cochrane Library, Clinicaltrials.gov, and PubMed were reviewed systematically in June 2019 and rechecked in November 2019 for the past 5 years with keywords like child, safety, hyperlipidemia, and statins, which resulted in nine randomized clinical trials. In short, statins are shown to be intermediately effective—median decrease of low-density lipoprotein cholesterol was 32% achieving the target of < 160 mg/dL in 67% of patients—in lowering lipid levels yet preventing early complications. They are also considered safely tolerated in most cases, even when taken for extended periods, but still not evidently permissible for children below 8 years old, which was the average age of all participants in the trials. Statins should not be given generally for pediatrics of less than 8 years old, in contrast to what was mentioned in the American Heart Association guideline (0–19 age range), since there is no evidence supporting their safety within this age group.
Factors Affecting Quality of Life among Post-Stroke Patients in the Sub-Himalayan Region
Authors: Ahmed Tarannum , Tamanna  , Kumar Rajesh , Bahurupi Yogesh
Published: October 2020

Background Stroke is one of the most debilitating conditions contributing to significant disability and death globally. Identifying risk factors for quality of life (QoL) will enable to improve home-based rehabilitation in post-stroke phase.

Objective This study was aimed to identify the risk factors of QoL in stroke patients in the sub-Himalayan region.

Materials and Methods A cross-sectional hospital-based study assessed the QoL among stroke patients within a week after the onset of acute stroke and then re-evaluated at 3 months. World Health Organization QoL-BREF, Beck Depression Inventory, the Barthel Index, and Montreal Cognitive Assessment (MOCA) were used to seek data on QoL, depression, cognitive, and functional dependence status, respectively. Appropriate statistics were used to compute the results.

Results In total, 129 stroke patients recruited, out of which 102 returned to a 3-month follow-up. QoL, MOCA, disability index, and depression score were compared using Wilcoxon Singed-rank test. In multivariate analysis, depression and disability together predicted 60% of the variance for physical QoL (p < 0.0001). Similarly, poststroke depression and disability together predicted 61% of the variance for psychological QoL (p < 0.0001) in stroke patients.

Conclusion Findings indicated that depression and disability are leading risk factors of QoL in stroke patients. Early identification of poststroke depression and functional dependence status is, therefore, essential to devise screening procedure and to develop targeted intervention to improve rehabilitation outcomes.
Reifegradmodelle: Ist der Klinikeinkauf wirklich erfolgreicher, wenn er auf höheren Entwicklungsstufen agiert?
Authors: Rolf Philipp , Schlüchtermann Jörg
Published: October 2020

Wenn Kosten eingespart werden sollen, ist insbesondere der Klinikeinkauf gefordert. Dafür braucht es jedoch passende Strukturen und ein Management, das den Einkauf aktiv zu einem Werttreiber entwickelt. Kliniken sollten sowohl den IST-Zustand ihres Einkaufs kennen als auch einen möglicherweise geeigneteren SOLL-Zustand identifizieren können. Hierbei können Reifegradmodelle helfen.
Solvent dependence of photophysical and photochemical behaviors of thioxanthen-9-one
Authors: Chen Lin , Wang Lei , Zheng Min , Wang Lin
Published: October 2020

The photophysical and photochemical behaviors of thioxanthen-9-one (TX) in different solvents have been studied using nanosecond transient absorption spectroscopy. A unique absorption of the triplet state 3TX* is observed, which involves two components, 3nπ* and 3ππ* states. The 3ππ* component contributes more to the 3TX* when increasing the solvent polarity. The self-quenching rate constant ksq of 3TX* is decreased in the order of CH3CN, CH3CN/CH3OH (1:1), and CH3CN/H2O (1:1), which might be caused by the exciplex formed from hydrogen bond interaction. In the presence of diphenylamine (DPA), the quenching of 3TX* happens efficiently via electron transfer, producing the TX·− anion and DPA·+ cation radicals. Because of insignificant solvent effects on the electron transfer, the electron affinity of the 3nπ* state is proved to be approximately equal to that of the 3ππ* state. However, a solvent dependence is found in the dynamic decay of TX·– anion radical. In the strongly acid aqueous acetonitrile (pH=3.0), a dynamic equilibrium between protonated and unprotonated TX is definitely observed. Once photolysis, 3TXH+* is produced, which contributes to the new band at 520 nm.
Collapse of four-arm stars polyelectrolyte brushes under an electric field in the presence of trivalent salt coions
Authors: Ji Yu , Wang Shao-yun , Tong Chao-hui
Published: October 2020

Langevin dynamics simulations were conducted to study the collapse of grafted partially charged 4-arm star chains onto the oppositely charged grafting electrode in the presence of trivalent salt coions. Simulation results reveal that the average charge fraction of the grafted star chains and the salt concentration play critical roles in the competitive adsorption of charged monomers and trivalent salt coions onto the oppositely charged electrode. For grafted star chains with relatively high charge fraction, charged monomers are the dominant species collapsing on the oppositely charged electrode with the emergence of charge reversal on the grafting electrode. At a low charge fraction such that the total amount of charges on a grafted star molecule is comparable to that of a trivalent salt coion, trivalent salt coions absorb more strongly onto the electrode than grafted stars even at very low salt concentration. It is found that at relatively low charge fraction of star chains, the addition of trivalent salt coions does not lead to charge overcompensation of the surface charges on the grafting electrode. The stretching of star brushes under an electric field in the presence of trivalent salt coions was also briefly investigated.
A novel silicon etching method using vapor of tetramethylammonium hydroxide solution
Authors: He Jian , Zhao Yue-fang , Xu Fang-liang , Zhao Dong-yang , Hou Xiao-juan , Chou Xiu-jian
Published: October 2020

Silicon bulk etching is an important part of micro-electro-mechanical system (MEMS) technology. In this work, a novel etching method is proposed based on the vapor from tetramethy-lammonium hydroxide (TMAH) solution heated up to boiling point. The monocrystalline silicon wafer is positioned over the solution surface and can be anisotropically etched by the produced vapor. This etching method does not rely on the expensive vacuum equipment used in dry etching. Meanwhile, it presents several advantages like low roughness, high etching rate and high uniformity compared with the conventional wet etching methods. The etching rate and roughness can reach 2.13 µm/min and 1.02 nm, respectively. Furthermore, the diaphragm structure and Al-based pattern on the non-etched side of wafer can maintain intact without any damage during the back-cavity fabrication. Finally, an etching mechanism has been proposed to illustrate the observed experimental phenomenon. It is suggested that there is a water thin film on the etched surface during the solution evaporation. It is in this water layer that the ionization and etching reaction of TMAH proceed, facilitating the desorption of hydrogen bubble and the enhancement of molecular exchange rate. This new etching method is of great significance in the low-cost and high-quality micro-electromechanical system industrial fabrication.
Dissociative electron attachment to carbon dioxide
Authors: Wu Bin , Wang Xu-dong , Gao Xiao-fei , Li Hao , Tian Shan Xi
Published: October 2020

Our experimental progresses on the reaction dynamics of dissociative electron attachment (DEA) to carbon dioxide (CO2) are summarized in this review. First, we introduce some fundamentals about the DEA dynamics and provide an epitome about the DEAs to CO2. Second, the experimental technique developments are described, in particular, on the high-resolution velocity map imaging apparatus in which we put a lot of efforts during the past two years. Third, our findings about the DEA dynamics of CO2 are surveyed and briefly compared with the others’ work. At last, we give a perspective about the applications of the DEA studies and highlight the inspirations in the production of molecular oxygen on Mars and the catalytic transformations of CO2.
Characterization of a time-resolved electron microscope with a Schottky field emission gun
Authors: Olshin Pavel K. , Drabbels Marcel , Lorenz Ulrich J.
Published: October 2020

The rapid growth of the field of time-resolved and ultrafast electron microscopy has been accompanied by the active development of new instrumentation. Recently, time-resolved microscopes equipped with a field emission gun have been introduced, demonstrating great potential for experiments that benefit from the high brightness and coherence of the electron source. Here, we describe a straightforward design of a time-resolved transmission electron microscope with a Schottky field emission gun and characterize its performance. At the same time, our design gives us the flexibility to alternatively operate the instrument as if it was equipped with a flat metal photocathode. We can, thus, effectively choose to sacrifice brightness in order to obtain pulses with vastly larger numbers of electrons than from the emitter if for a given application the number of electrons is a crucial figure of merit. We believe that our straightforward and flexible design will be of great practical relevance to researchers wishing to enter the field.
Measurements and modeling of ion divergence from a gridded inertial electrostatic confinement device using laser induced fluorescence
Authors: Ranson Nicholas , Pigeon Valentin , Claire Nicolas , Khachan Joe
Published: October 2020

Inertial electrostatic confinement (IEC) is a method of confining and heating a plasma at benchtop scales to sufficient energies for nuclear fusion to occur. Ion velocity and flow direction were measured in an IEC discharge using laser induced fluorescence (LIF) on argon ions. A cathode of two parallel rings, with a common axis of symmetry, resulted in predominant discharge beams, otherwise known as microchannels, along this axis. The device was operated in the abnormal glow discharge regime where both current and voltage increase monotonically, replicating a conventional high voltage IEC device. It was found that argon ions accelerated and flowed outward from the midpoint between the rings along the axis; we have labeled this ion motion as being divergent. The predominant direction of ion flow in the discharge is opposite to the conventional ion focus model, where the discharge at the cathode center is assumed to be the result of ion flow toward it from outside of the cathode. An ion sheath model is shown to produce a virtual anode at the axial midpoint between the rings. The model also shows that ions within the virtual anode are accelerated outward with a spatial velocity profile that replicates those measured using LIF.
Cavitation bubble collapse between parallel rigid walls with the three-dimensional multi-relaxation time pseudopotential lattice Boltzmann method
Authors: Peng Haonan , He Xiaolong , Zhang Jianmin , Wang Yurong
Published: October 2020

Studying the flow characteristics of bubbles in a narrow gap is an important problem related to bearing cavitation and gas–liquid two-phase flow. In this paper, we present a modified three-dimensional multi-relaxation-time pseudo-potential model for large density ratio multiphase phenomena. The accuracy of the model is verified by the Maxwell construction, Laplace law, and Rayleigh–Plesset equation. The influence of the force scheme parameter and the dimensionless relaxation time on the thermodynamic consistency of the model is analyzed. The results show that the three-dimensional lattice Boltzmann pseudo-potential model proposed in this paper has good numerical stability in simulating multiphase phenomena. Furthermore, the cavitation bubble collapse process between parallel rigid walls is simulated by the proposed model. The collapse process obtained by the present method agrees well with the experimental result. The different orientations for the bubble to the wall exert a significant influence on the variation of the pressure field, velocity field, and evolution of maximum pressure and micro-jet velocity. During the cavitation bubble collapse process, the pressure and the velocity at the collapse point will increase instantaneously, and the orientation for the bubble to the wall is a key factor to determine the collapsed form of the cavitation bubble. The results verified the practicability of the addressed model to study the collapse of three-dimensional cavitation bubbles in the presence of parallel rigid walls.
Correlation between the step–terrace structure and the nitrogen doping variation observed on the (0001¯) facet of 4H-SiC crystals
Authors: Yokomoto Kaito , Yabu Masahiro , Hashiguchi Takato , Ohtani Noboru
Published: October 2020

The variation in nitrogen doping concentration on the (0001¯) facet of 4H-SiC single crystals grown by the physical vapor transport (PVT) growth method was investigated using Raman scattering microscopy. The observed variation was well correlated with the terrace-width variation in the step–terrace structure on the facet; regions with unevenly distributed terrace-widths always showed a lower nitrogen concentration compared to those having evenly distributed terrace-widths. It was revealed by low-energy electron channeling contrast imaging that in lower nitrogen concentration regions, terraces with two dangling bonds per silicon atom at the step riser in the step-down direction always became wider. On the basis of these experimental results, the nitrogen incorporation kinetics during PVT growth of 4H-SiC crystals was discussed.
Intrinsic thermal interfacial resistance measurement in bonded metal–polymer foils
Authors: Rajagopal Manjunath C. , Man Timothy , Agrawal Adreet , Kuntumalla Gowtham , Sinha Sanjiv
Published: October 2020

Heat conduction through bonded metal–polymer interfaces often limits the overall heat transfer in electronic packaging, batteries, and heat recovery systems. To design the thermal circuit in such systems, it is essential to measure the thermal interfacial resistance (TIR) across ∼1 µm to 100 µm junctions. Previously reported TIR of metal–polymer junctions utilize ASTM E1530-based two-block systems that measure the TIR by applying pressure across the interface through external heating and cooling blocks. Here, we report a novel modification of the ASTM-E1530 technique that employs integrated heaters and sensors to provide an intrinsic TIR measurement of an adhesively bonded metal–polymer junction. We design the measurement technique using finite element simulations to either passively suppress or actively compensate the lateral heat diffusion through the polymer, which can minimize the systematic error to ≲5%. Through proof-of-concept experiments, we report the TIR of metal–polymer interfaces made from DuPont’s Pyralux double-side copper-clad laminates, commonly used in flexible printed circuit boards. Our TIR measurement errors are <10%. We highlight additional sources of errors due to non-idealities in the experiment and discuss possible ways to overcome them. Our measurement technique is also applicable to interfaces that are electrically insulating such as adhesively joined metal–metal junctions and sputter-coated or welded metal–polymer junctions. Overall, the technique is capable of measuring TIR ≳10−5 m2 KW−1 in bonded metal–polymer foils and can be tailored for in situ measurements in flexible electronics, circuit packaging, and other hybrid metal–polymer systems.
Measurements of ion velocity distributions in a large scale laser-produced plasma
Authors: Dorst R. S. , Heuer P. V. , Schaeffer D. B. , Constantin C. G. , Niemann C.
Published: October 2020

Laser-produced plasma velocity distributions are an important, but difficult quantity to measure. We present a non-invasive technique for measuring individual charge state velocity distributions of laser-produced plasmas using a high temporal and spectral resolution monochromator. The novel application of this technique is its ability to detect particles up to 7 m from their inception (significantly larger than most laboratory plasma astrophysics experiments, which take place at or below the millimeter scale). The design and assembly of this diagnostic is discussed in terms of maximizing the signal to noise ratio, maximizing the spatial and temporal resolution, and other potential use cases. The analysis and results of this diagnostic are demonstrated by directly measuring the time-of-flight velocity of all ion charge states in a laser produced carbon plasma.
The rate of development of atomic mixing and temperature equilibration in inertial confinement fusion implosions
Authors: Haines Brian M. , Shah R. C. , Smidt J. M. , Albright B. J. , Cardenas T. , Douglas M. R. , Forrest C. , Glebov V. Yu. , Gunderson M. A. , Hamilton C. , Henderson K. , Kim Y. , Lee M. N. , Murphy T. J. , Oertel J. A. , Olson R. E. , Patterson B. M. , Randolph R. B. , Schmidt D.
Published: October 2020

The MARBLE project is a novel inertial confinement fusion platform for studying the development of atomic mixing and temperature equilibration in inertial confinement fusion implosions and their impact on thermonuclear burn. Experiments involve the laser-driven implosion of capsules filled with deuterated engineered foams whose pores are filled with a gaseous mixture of hydrogen and tritium. By varying the size of the foam pores, we can study the timescale of the development of atomic mix relative to the development of thermal equilibrium between species. In contrast, previous separated reactant experiments have only provided information on the total amount of mix mass. We report on the series of MARBLE experiments [first reported in Haines et al., Nat. Commun. 11, 544 (2020)] performed on the University of Rochester's OMEGA laser facility and detailed and highly resolved three-dimensional radiation-hydrodynamic simulations of the implosions. In both the experimental and simulation results, we observe that the reactants do not achieve thermal equilibrium during the course of the implosion except in atomically mixed regions—i.e., that atomic mixing develops faster than thermal equilibration between species. The results suggest that ion temperature variations in the mixture are at least as important as reactant concentration variations for determining the fusion reaction rates.
An efficient and accurate model for water with an improved non-bonded potential
Authors: Mohebifar Mohamad , Rowley Christopher N.
Published: October 2020

A molecular mechanical model for liquid water is developed that uses a physically motivated potential to represent Pauli repulsion and dispersion instead of the standard Lennard-Jones potential. The model has three atomic sites and a virtual site located on the ∠HOH bisector (i.e., a TIP4P-type model). Pauli-repulsive interactions are represented using a Buckingham-type exponential decay potential. Dispersion interactions are represented by both C6/r6 and C8/r8 terms. This higher order C8 dispersion term has been neglected by most force fields. The ForceBalance code was used to define parameters that optimally reproduce the experimental physical properties of liquid water. The resulting model is in good agreement with the experimental density, dielectric constant, enthalpy of vaporization, isothermal compressibility, thermal expansion coefficient, diffusion coefficient, and radial distribution function. A graphical processing unit-accelerated implementation of this improved non-bonded potential can be employed in OpenMM without modification by using the CustomNonBondedForce feature. The efficient and automated parameterization of these non-bonded potentials provides a rational strategy to define a new molecular mechanical force field that treats repulsion and dispersion interactions more rigorously without major modifications to the existing simulation codes or a substantially larger computational cost.
Controlling x-ray flux in hohlraums using burnthrough barriers
Authors: Trickey William , Owen Joseph , Ridgers Christopher , Pasley John
Published: October 2020

A technique for controlling x-ray flux in hohlraums is presented. In indirect drive inertial confinement fusion (ICF), the soft x-rays arriving at the spherical fuel capsule are required to have a specific temporal profile and high spatial uniformity in order to adequately compress and ignite the fuel. Conventionally, this is achieved by modifying the external driver, the hohlraum geometry, and the sites of interaction between the two. In this study, a technique is demonstrated which may have utility in a number of scenarios, both related to ICF and otherwise, in which precise control over the x-ray flux and spatial uniformity are required. X-ray burnthrough barriers situated within the hohlraum are shown to enable control of the flux flowing to an x-ray driven target. Control is achieved through the design of the barrier rather than by modification of the external driver. The concept is investigated using the one-dimensional (1D) radiation hydrodynamics code HYADES in combination with a three-dimensional (3D) time-dependent view-factor code.
Theoretical studies of equilibrium beta limit in LHD plasmas
Authors: Suzuki Y. , Watanabe K. Y. , Sakakibara S.
Published: October 2020

This study deals with the equilibrium beta limit for high-beta plasmas of the Large Helical Device using a 3D equilibrium calculation code, HINT, which is an initial value solver based on the relaxation method without an assumption of nested flux surfaces. For the finite beta equilibrium, due to the nonlinear 3D equilibrium response, the flux surface breaking begins, and the magnetic field line becomes stochastic in the peripheral region. However, although the magnetic axis shifts until the conventional theoretical beta limit, the separatrix limiting the equilibrium does not appear in the plasma core. For the high beta equilibrium, breaking of the force balance begins in the strongly stochastized region. To keep the force balance in that region, the pressure gradient decreases and the fixed profile is relaxed. As a result, the volume averaged beta, which is equivalent to the plasma stored energy, saturates, although the peak beta increases. The beta value, where the force balance begins breaking in the inside of the stochastic region, is proposed as a new index of the equilibrium beta limit for the typical heliotron-type stellarator. According to this new index of the equilibrium beta limit, the achieved beta value in the experiment of the Large Helical Device is still lower than the equilibrium beta limit. This suggests that if the heating power can be increased, the achieved beta value may still increase.