bluuebunny/crossref_metadata_2025 huggingface dataset:
Controllable fabrication of Ag-NP-decorated porous ZnO nanosheet arrays with superhydrophobic properties for high performance SERS detection of explosives
Authors: He Xuan , Liu Yu , Liu Yi , Cui Sheng , Liu Wei , Li Zhongbo
Published: December 2019

An efficient hydrophobic condensation surface was developed and used as an ultrasensitive and stable SERS sensor based on ZnO–Ag hybrid mesoporous nanosheet (MNS) arrays for natural explosive sample detection.
A facile non-injection phosphorus-free synthesis of semiconductor nanoparticles using new selenium precursors
Authors: Prodanov Maksym , Diakov Maksym , Vashchenko Valerii
Published: December 2019

New Se-precursors enable the phosphorus-free non-injection synthesis of luminescent quantum dots and nanotetrapods as well as the injection-based synthesis of quantum rods.
Ordering self-assembly structures via intermolecular Br⋯S interactions
Authors: Hu Tianze , Wang Yujia , Dong Meiqiu , Wu Juntian , Pang Peng , Miao Xinrui , Deng Wenli
Published: December 2019

Br⋯S interactions are vital for the highly ordered self-assembled architectures of Br-DTBDT.
Surface grafted agents with various molecular lengths and photochemically active benzophenone moieties
Authors: Nordendorf Gaby , Schafforz Samuel L. , Käkel Eireen B. , Miao Shunyi , Lorenz Alexander
Published: December 2019

Homologues of benzophenone silane, a covalently graftable, photochemically active surface functionalizing agent, are investigated as surface functionalization agents for both small particles and planar substrates.
Molecular graphs and molecular conduction: the d-omni-conductors
Authors: Fowler Patrick W. , Borg Martha , Pickup Barry T. , Sciriha Irene
Published: December 2019

Graph–theoretical distance gives a complete classification of conduction behaviour of alternant and non-alternant molecular devices within the source-sink-potential model.
The effect of nanoscale friction of mesoporous carbon supported ionic liquids on the mass transfer of CO2 adsorption
Authors: Fan Pengpeng , Qiu Xiuhua , Shah Faiz Ullah , Ji Qingmin , An Rong
Published: December 2019

The nanofriction was linked with CO2 mass transfer at ionic liquid–solid interfaces, where the smaller nanofriction accelerates the CO2 adsorption.
Electronic structure and magnetic properties of the triangular nanographenes with radical substituents: a DFT study
Authors: Minkin Vladimir I. , Starikov Andrey G. , Starikova Alyona A. , Gapurenko Olga A. , Minyaev Ruslan M. , Boldyrev Alexander I.
Published: December 2019

DFT modeling of triangular polycyclic hydrocarbons bearing radicals provided insights into dependence of electronic ground states on their structural peculiarities
Model systems for screening and investigation of lithium metal electrode chemistry and dendrite formation
Authors: Kamphaus Ethan P. , Hight Karoline , Dermott Micah , Balbuena Perla B.
Published: December 2019

A simple approach based on first principles leads to investigation of the origins of dendritic growth.
The use of manganese oxide-coated sand for the removal of trace metal ions from stormwater
Authors: Charbonnet Joseph A. , Duan Yanghua , Sedlak David L.
Published: December 2019

Manganese oxide-coated sand can remove toxic metals from stormwater for years before regeneration with a mild acid. This geomedia could facilitate the use of stormwater as a water supply.
Anti-inflammatory action of two novel peptides derived from peanut worms (Sipunculus nudus) in lipopolysaccharide-induced RAW264.7 macrophages
Authors: Sangtanoo Papassara , Srimongkol Piroonporn , Saisavoey Tanatorn , Reamtong Onrapak , Karnchanatat Aphichart
Published: December 2019

Peanut worm (Sipunculus nudus Linn.) protein was hydrolyzed by three proteases and NO scavenging activity of the protein hydrolysates were evaluated.
Photochemical oxidation of benzylic primary and secondary alcohols utilizing air as the oxidant
Authors: Nikitas Nikolaos F. , Tzaras Dimitrios Ioannis , Triandafillidi Ierasia , Kokotos Christoforos G.
Published: December 2019

A mild and green photochemical protocol for the oxidation of alcohols to aldehydes and ketones was developed.
Iron-catalyzed cross-dehydrogenative coupling of indolin-2-ones with active methylenes for direct carbon–carbon double bond formation
Authors: Tan Zhi-Yu , Wu Ke-Xin , Huang Lu-Shan , Wu Run-Shi , Du Zheng-Yu , Xu Da-Zhen
Published: December 2019

A novel iron-catalyzed cross-dehydrogenative coupling of two different C(sp3)–H bonds to synthesize olefins by using air as an ideal oxidant.
Editorial: Evidence of a significant advance in green chemistry
Authors: Jessop Philip
Published: December 2019

Guidance to authors on providing evidence of a significant advance in green chemistry.
Measurements of mass-dependent Te isotopic variation by hydride generation MC-ICP-MS
Authors: Wasserman N. L. , Johnson T. M.
Published: December 2019

A new method for precise measurements of tellurium stable isotope variations by hydride generation MC-ICP-MS is presented, including a revised sample preparation scheme.
All-in-one platform for salivary cotinine detection integrated with a microfluidic channel and an electrochemical biosensor
Authors: Lee Kyungyeon , Yoon Taehee , Yang Hee-seon , Cha Sunyeong , Cheon Yong-Pil , Kashefi-Kheyrabadi Leila , Jung Hyo-Il
Published: December 2019

An all-in-one platform is presented to basically collect the human saliva and directly deliver it onto an electrochemical biosensing surface. Salivary cotinine is accurately analyzed with the aid of the meticulously developed platform.
A near infrared dye-coated silver nanoparticle/carbon dot nanocomposite for targeted tumor imaging and enhanced photodynamic therapy
Authors: Liu Rongjun , Yang Zhengmin , Zhang Liangliang , Zhao Jingjin , Hou Cheng , Zhao Shulin
Published: December 2019

A NIR dye-coated silver nanoparticle/carbon dot nano-composite (CyOH–AgNP/CD) was synthetized as a novel nanophotosensitizer for targeted tumor imaging and high-efficiency PDT. The CyOH–AgNP/CD exhibit potential for future clinical imaging-guided PDT.
Sound-driven dissipative self-assembly of aromatic biomolecules into functional nanoparticles
Authors: Bhangu Sukhvir Kaur , Bocchinfuso Gianfranco , Ashokkumar Muthupandian , Cavalieri Francesca
Published: December 2019

The out-of-equilibrium self-assembly of simple aromatic amino acid molecules is driven by high frequency ultrasound, where acoustic energy acts as a fuel to form uniform supramolecular nanostructures with multifarious optical and biological properties.
High-performance liquid chromatography associated with resonance Rayleigh scattering spectral study of the interactions of palladium(ii)–antimigraine chelates with Erythrosin B and their analytical applications
Authors: Li Shiyu , Zhang Zhongying , Peng Jingdong , Wang Xiang , Long Dengying , Xian Hong , Ni Ranxi , Peng Huanjun , Chen Jun
Published: December 2019

For the first time, a highly sensitive and selective detection technology of high-performance liquid chromatography associated with resonance Rayleigh scattering spectra (HPLC-RRS) is applied to analyze migraine drugs including zolmitriptan (ZON) and rizatriptan (RIN).
The role of iodine in the enhancement of the supercapacitance properties of HI-treated flexible reduced graphene oxide film: an experimental study with insights from DFT simulations
Authors: Kamila Swagatika , Kandasamy Manikandan , Chakraborty Brahmananda , Jena Bikash Kumar
Published: December 2019

Iodine on graphene frameworks enhances the specific capacitance towards supercapacitor applications.
A highly sensitive Ru(ii) complex-based phosphorescent probe for thiophenol detection with aggregation-induced emission characteristics
Authors: Yang Linlin , Li Lili , Li Yanping , Zheng Huimin , Song Huaxiong , Zhang Haihua , Yang Nan , Ji Liguo , Ma Nana , He Guangjie
Published: December 2019

A novel AIEE-active Ru(ii) based phosphorescent probe was designed for the detection of thiophenol in aqueous solution and on test paper.
Selective synthesis of trisubstituted pyrroles through the reactions of alkynyl Fischer carbene complexes with oxazolones
Authors: López Julio , Velazco-Cabral Iván , Rodríguez-deLeón Eloy , Villegas Gómez Clarisa , Delgado Francisco , Tamariz Joaquín , Arrieta Ana , Cossío Fernando P. , Vázquez Miguel A.
Published: December 2019

The unexpected reactivity of fluorinated oxazolones with alkynyl Fischer carbenes is reported. The loss of the –CF3 and a cascade process involving nucleophilic additions were observed.
Effective removal of uranium from aqueous solution by using novel sustainable porous Al2O3 materials derived from different precursors of aluminum
Authors: Liao Jun , Zhang Yong
Published: December 2019

Novel porous Al2O3 materials with high adsorption capacity for U(vi) were prepared via solution-freeze-drying-calcination technology.
Homogeneous coating of carbon nanotubes with tailored N-doped carbon layers for improved electrochemical energy storage
Authors: He Yi , Li Hong , Zhang Qing , He Chengen , Zhang Xiaofang , Yang Yingkui
Published: December 2019

Polyimide-derived N-doped carbon layers were coated onto carbon nanotubes for high-rate electrodes with enhanced energy storage.
Synthesis and characterization of cyclobutenedione–bithiophene π-conjugated polymers: acetal-protecting strategy for Kumada–Tamao–Corriu coupling polymerization between aryl bromide and Grignard reagents
Authors: Ohishi Tomoyuki , Sone Takuma , Oda Kohei , Yokoyama Akihiro
Published: December 2019

Donor–acceptor-type π-conjugated polymers consisting of cyclobutenedione as an acceptor and bithiophene as a donor were synthesized by Kumada–Tamao–Corriu coupling polymerization of an acetal-protected monomer.
Roadmap for cost-effective, commercially-viable perovskite silicon tandems for the current and future PV market
Authors: Sofia Sarah E. , Wang Hao , Bruno Annalisa , Cruz-Campa Jose Luis , Buonassisi Tonio , Peters Ian Marius
Published: December 2019

A techno-economic analysis of perovskite-silicon tandem solar modules is presented, outlining the most viable pathway for designing cost-effective, commercially viable tandems.
A chlorinated nonacyclic carbazole-based acceptor affords over 15% efficiency in organic solar cells
Authors: Chen Tsung-Wei , Peng Kuan-Lin , Lin You-Wei , Su Yi-Jia , Ma Ko-Jui , Hong Ling , Chang Chia-Chih , Hou Jianhui , Hsu Chain-Shu
Published: December 2019

A systematic approach involving conjugation extension and end group chlorination is capable of enhancing both JSC and PCE. Overall, the PM6:DTTC-4Cl-based device delivers a remarkable PCE of 15.42% with a VOC of 0.92 V, a JSC of 22.64 mA cm−2 and an FF of 74.04%.
Broadband emissions from Lu2Mg2Al2Si2O12:Ce3+ plate ceramic phosphors enable a high color-rendering index for laser-driven lighting
Authors: Sun Peng , Hu Pan , Liu Yongfu , Liu Shuang , Dong Rui , Jiang Jun , Jiang Haochuan
Published: December 2019

By selecting color converters by some standards, such as Lu2Mg2Al2Si2O12:Ce3+ PCP, a high color-rendering index is achieved in laser-driven lighting.
Truncated singular value decomposition for through‐the‐wall microwave imaging application
Authors: Doğu Semih , Akıncı Mehmet Nuri , Çayören Mehmet , Akduman İbrahim
Published: December 2019

We considered differential through‐the‐wall microwave imaging with different formulations of truncated singular value decomposition (TSVD) method with a non‐anechoic experiment. Previous studies employ TSVD with single transmitting/measuring antenna, while we show how to apply the TSVD in case of a moving linear transmitting/measuring antenna array. Particularly, an averaging scheme is employed for repeated measurements. Three TSVD approaches are tested: (i) TSVD on Contrast Source, (ii) TSVD on Contrast, (iii) multi frequency TSVD on Contrast. For (i), the dimension of inverted matrix is relatively low. After solving equations, a normalisation is proposed for eliminating noise. For (ii), the reconstructions get better compared to (i) since measured data for all excitations are inverted simultaneously. Nevertheless, (ii) requires more time than (i), since the inverted matrix gets larger. Finally, for (iii), to avoid additional calibration, we employ the solutions of (ii). Then, the contrasts are estimated for all frequencies and excitations simultaneously. Thus, the inverted matrix is largest for (iii), accuracy is best, computational time is longest. For testing proposed techniques, a metallic scatterer is deployed behind a wall. Results show trade‐off between accuracy and computational time for choosing the suitable inversion method. Moreover, norm type selection is assessed for each method.
Von der Wissenschaft zur evidenzbasierten Praxis
Authors: Mehrholz Jan
Published: December 2019

Nunmehr zum dritten Mal fand der internationale Kongress NeuroRehabilitation and Neural Repair dieses Jahr vom 22. bis 24. Mai 2019 im Kongresszentrum in Maastricht statt. Insgesamt wurde eine deutliche Steigerung der Teilnehmer und Aussteller erreicht: über 800 Teilnehmer aus mehr als 35 Ländern.
Chancen und Grenzen der nicht invasiven Pränataldiagnostik
Authors: Hutter Stefan , Stamm Anja
Published: December 2019

Experten-Interview | Mit einem Bluttest können Schwangere seit 2012 feststellen lassen, ob ihr Kind das Down-Syndrom haben wird. Der nicht invasive Pränataltest ist risikoärmer und kann früher erfolgen als eine Fruchtwasseruntersuchung. Der Gemeinsame Bundesausschuss hat am 19. September 2019 beschlossen, dass ein NIPT in begründeten Einzelfällen nach ärztlicher Beratung unter Verwendung einer noch zu entwickelnden Versicherteninformation als Kassenleistung eingesetzt werden kann. Pränataldiagnostiker Dr. Stefan Hutter beschreibt die Untersuchungsmethode.
Intrauterine Behandlung der Spina bifida durch offene Fetalchirurgie
Authors: Elsässer Michael , Spratte Julia , Bächli Heidi , Beedgen Bernd , Lichtenstern Christoph , Weigand Markus , Pöschl Johannes , Unterberg Andreas , Fluhr Herbert , Sohn Christof
Published: December 2019

Seit 2016 praktiziert das Universitätsklinikum Heidelberg die offene fetalchirurgische Defektdeckung der Myelomeningocele (MMC). Ein großer Vorteil der Methode gegenüber der postpartalen Behandlung ist die Reduzierung der Shunt-Pflicht und die Verbesserung der motorisch-neurologischen Funktion der Hüfte und der unteren Extremität. Dieser Beitrag beschreibt Diagnostik, Beratung und Operation anhand eines Fallbeispiels und erläutert die Möglichkeiten sowie Grenzen des Eingriffs.
Hebammenmangel in deutschen Kreißsälen – Doulas füllen die Lücke
Authors: Hartmann Melanie
Published: December 2019

Durch den Fachkräftemangel fehlen Hebammen in den Kreißsälen der Krankenhäuser, aber auch freiberufliche Hebammen sind zunehmend rar. Deshalb steht vielen Frauen nicht die Betreuung zur Verfügung, die sie sich während und nach der Geburt wünschen. Die Rolle der Doulas wird dadurch immer wichtiger. Dieser Beitrag widmet sich dem aktuellen Forschungsstand zur Bedeutung der Doulas und setzt sich mit Konflikten und Potenzialen in der Zusammenarbeit mit Hebammen auseinander.
Patient-Centered Outcomes in Critical Illness: Will My Patient Be Functionally and Cognitively Intact?
Authors: Geer Jacqueline H. , Qi Wei , Ferrante Lauren E.
Published: December 2019

Survival in the intensive care unit (ICU) has steadily increased over the past several decades; millions of patients now survive a critical illness every year. ICU survivors are at a significantly increased risk of impairments in physical function, cognitive function, and mental health. These patient-centered outcomes are among the most meaningful to patients. Landmark studies concerning treatment preferences have demonstrated that patients value functional and cognitive outcomes over mortality. In this chapter, we discuss the determinants of functional and cognitive outcomes post critical illness to address the question, “Will my ICU patient be functionally and cognitively intact?”
Translational Research in Intensive Care Unit: Novel Approaches for Drug Development and Personalized Medicine
Authors: Samanta Romit J. , Summers Charlotte
Published: December 2019

The major clinical presentations seen by critical care physicians are sepsis and acute respiratory distress syndrome (ARDS), both of which are heterogeneous clinical syndromes rather than specific diagnoses. The current diagnostic criteria provide little insight into the mechanisms underlying these heterogeneous syndromes and minimal progress has been made with regard to the development of therapies, despite many large randomized controlled trials being undertaken. This review outlines the advances made in improved characterization of critically-ill patients, using ARDS as an exemplar, and highlights the need for this improved patient characterization to be coupled with mechanistic science to develop therapies that target specific pathomechanisms.
Potential for Increased Epilepsy Awareness: Impact of Health Education Program in School on Teachers and Children
Authors: Murthy Meena Kolar Sridara , Rajaram Prakashi , Mudiyanuru Kannappa Shetty , Marimuthu P , Govindappa Lakshmana , Dasgupta Madhuporna
Published: December 2019

Background Although epilepsy is a common disorder, it is highly stigmatized. Not only public but even teachers are not free from stigmatization and cultural barriers. Under this condition, children with epilepsy are more vulnerable for stigmatization, social isolation, lack of support, and psychological and emotional problems. At the same time, there is an immediate need of literature focusing on intervention studies to change the attitudes of school teachers and children.

Materials and Methods The study was conducted with the objectives to evaluate knowledge, attitude, and practices about epilepsy among school teachers and children; provide educational training program to teachers; and check the efficacy of training program imparted by teacher and trainer.

Results Repeated measure of analysis of variance shows that knowledge (F = 1134.875, p < 0.001), attitude (F = 2429.909, p < 0.001), and practice (F = 2205.122, p < 0.001) are significantly different between pre- and posttest indicated by Pillai’s trace test. Similarly, from the Pillai’s test knowledge (F = 49.317, p < 0.001), attitude (F = 125.304, p < 0.001) and practice (F = 178.697, p < 0.001) are significantly different among the teachers, trainer imparted training group of children, and teachers imparted training group of children groups. It is seen that knowledge, attitude, and practice scores significantly differ between two time points and across three groups. Among all the groups, teachers imparted training group children had high level of practice.

Conclusion Inclusion of health education programs in the textbooks and health education schemes for teachers and school children is a crucial way to bring a change in their attitude, behavior, and practices.
Effect of Pregabalin on Postcraniotomy Pain in Patients Undergoing Supratentorial Tumor Surgery: A Randomized, Double-Blind, Placebo-Controlled Trial
Authors: Lamsal Ritesh , Mahajan Charu , Chauhan Vikas , Gupta Nidhi , Mishra Nitasha , Rath Girija Prasad
Published: December 2019

Background and Objectives Suboptimal management of postcraniotomy pain causes sympathetic and hemodynamic perturbations, leading to deleterious effects on the neurological system and overall patient outcome. Opioids are the mainstay of postoperative pain management but have various problems when given in high doses, or for prolonged durations in neurosurgical patients. The ideal method of pain control following craniotomy generally relies on a combination of various drugs. Oral pregabalin may be an attractive alternative in these patients.

Materials and Methods Sixty, American Society of Anesthesiologists class I and II patients posted for elective supratentorial craniotomy, aged 18 and 60 years, were randomly assigned into three groups of 20 each to receive oral placebo (Group A), pregabalin 75 mg (Group B), or pregabalin 150 mg (Group C) before the induction of anesthesia. At the end of the surgery, patient-controlled analgesia was started with intravenous fentanyl. Visual analog scale (VAS) score was recorded every 2 hours for 24 hours, along with total postoperative fentanyl requirement.

Results There were no differences in sex, duration of surgery or anesthesia and total intraoperative fentanyl administered among the three groups. The median postoperative VAS score (Group A—18.0, Group B—20, and Group C—22.0; p = 0.63) was similar in all the groups. However, postoperative fentanyl requirement over 24 hours was least in the group that received 150 mg pregabalin (Group A—190 μg, Group B—240 μg, and Group C—100 μg; p = 0.03).

Conclusions Even though pain scores were not significantly different, patients receiving 150 mg oral pregabalin required the least amount of postoperative opioids.
Avalanche charge generation in anhydrous glucosides excited by an external electric field
Authors: Sugimura Akihiko , Iwamoto Mitsumasa , Hashim Rauzah
Published: December 2019

Glycolipids are components of cellular membranes comprising a hydrophobic lipid tail and one or more hydrophilic sugar heads, and are widely associated with the fields of life science and biochemistry. Due to the hygroscopic nature of sugar, the dry thermotropic phases of glycolipids have fewer studies. We report on the electric charge generation in anhydrous glucosides excited by the external high electric field (∼2 MV/m). This causes a large current in the smectic A phase, but not in the isotropic phase. Its intensity is about 100 times larger than the steady state current. The generation of the current was found to be irreversible by the repetition of the field application. The large electric carrier generation is originated in the smectic A phase, possibly due to an electron avalanche breakdown mechanism caused by the collisions of electrons through the impact ionization.
Experimental investigation of co-flow jet’s airfoil flow control by hot wire anemometer
Authors: Bahrami A. , Hoseinzadeh S. , Heyns P. S. , Mirhosseini S. M.
Published: December 2019

An experimental flow control technique is given in this paper to study the jet effect on the coflow jet’s airfoil with injection and suction and compared with the jet-off condition. The airfoil is CFJ0025-065-196, and the Reynolds number based on the airfoil’s chord length is 105. To measure the turbulence components of flow, a hot wire anemometry apparatus in a wind tunnel has been used. In this paper, the effect of the average velocity and boundary layer thickness on the coflow jet’s airfoil is analyzed. The test is done for two different coflow velocities and for different angles of attack. It is also shown that, by increasing the velocity difference between the jet and the main flow, separation is delayed, and this delay can be preserved by raising coflow velocity at higher angles of attack. So, this flow control method has a good efficiency, and it is possible to reach higher numbers of lift and lower numbers of drag coefficients.
Hydrogen-gas sensing at low concentrations using extremely narrow gap palladium nanoclusters prepared by resistive spectroscopy
Authors: Nakamura N. , Ueno T. , Ogi H.
Published: December 2019

Isolated palladium nanostructures expand when they are exposed to hydrogen gas, and the gaps between them become narrower, thereby decreasing the electrical resistance. This behavior is applicable for the hydrogen-gas sensing, and several types of nanogap structures have been developed. However, the resistance change is significantly small at a low hydrogen-gas concentration because of insignificant lattice expansion. In the present study, this problem is solved by using the palladium nanoclusters with extremely narrow gaps, which is achieved by our original method, resistive spectroscopy, and hydrogen-induced structural stabilization. The nanoclusters are fabricated by interrupting deposition just before forming the continuous film, in which palladium clusters are nearly touching each other, and exposing them to hydrogen gas. In conventional studies using nanoclusters, hydrogen gas is detected through a decrease in the surface electric resistance caused by gap narrowing/closing. However, in this study, we observe an increase in the resistance when the gap distance between the cluster is extremely small, which is attributed to the restriction of electron tunneling between the palladium nanoclusters because of hydrogen adsorption on their surface. We confirm that this mechanism allows ultrahigh sensitivity hydrogen-gas sensing, achieving a limit of detection of 0.25-ppm hydrogen gas. In addition, we find that an optimized structure for the present detection mechanism is different from those in conventional sensors based on the gap-narrowing/closing mechanism.
Generative dynamic link prediction
Authors: Chen Jinyin , Lin Xiang , Jia Chenyu , Li Yuwei , Wu Yangyang , Zheng Haibin , Liu Yi
Published: December 2019

In networks, a link prediction task aims at learning potential relations between nodes to predict unknown potential linkage states. At present, most link prediction methods are used to process static networks. These methods cannot produce good prediction results for dynamic networks. However, for most dynamic networks in the real world, the vertices and links of these networks change over time. Dynamic link prediction (DLP) has attracted more attention as it can better mimic the evolution nature of the networks. Inspired by successful applications of the generative adversarial network in generating fake images, which are comparable with the real ones, we propose a novel generative dynamic link prediction (GDLP) method. Different from other DLP methods, we model the link prediction task as a network generation process. More specifically, GDLP utilizes the historical networks structure information to generate the network snapshot of next time stamp by an end-to-end deep generative model. This model contains a generator and a discriminator. The generator of GDLP is a spatiotemporal prediction model, which is responsible for generating the future networks based on the historical network snapshots, while the discriminator is a classification model to classify the generated networks and the ground-truth ones. With the two-player game training and learning strategy, GDLP is capable of accurate prediction for dynamic networks using the structural and temporal information. Experimental results validate that GDLP significantly outperforms several existing baseline methods on many types of dynamic networks, which improves the effectiveness of dynamic link prediction.
Rich diversity of crystallographic phase formation in 2D RexMo1 – xS2 (x < 0.5) alloy
Authors: Sharona H. , Vishal B. , Bhat U. , Paul A. , Mukherjee A. , Sarma S. C. , Peter S. C. , Datta R.
Published: December 2019

We report on the observation of the rich variety of crystallographic phase formation in a RexMo1 – xS2 alloy for x < 0.5. For x < 0.23, no low dimensional superstructural modulation is observed and inter cation hybridization remains discrete, forming dimers to tetramers with increasing Re concentration. For x > 0.23, superstructural modulation is observed. Depending on the Re concentrations (x = 0.23, 0.32, 0.38, and 0.45) and its distributions, various types of cation hybridization result in the rich variety of low dimensional superstructural modulation as directly revealed by high resolution transmission electron microscopy. These layered alloy systems may be useful for various energy and novel device applications.
Continuously-fed gravity currents propagating over a finite porous substrate
Authors: Venuleo Sara , Pokrajac Dubravka , Schleiss Anton J. , Franca Mário J.
Published: December 2019

We present the results of laboratory investigations of continuously-fed density currents that propagate first over a smooth horizontal bed and then over a porous substrate of limited length. Inflow discharge, initial excess density, and substrate porosities are varied. Density measurements, acquired through an image analysis technique, are performed above the porous layer simultaneously with quasi-instantaneous vertical velocity profiles. After a first phase in which the current sinks into the substrate, freshwater entrainment from the bed begins and, gradually, a mixing layer forms at the interface between the surface flow and the porous bed. Shear-driven and Rayleigh-Taylor instabilities rule the dynamics of this mixing layer. The porous boundary effects are observed in the vertical distributions of both density and velocity, especially in the near-bed region. Here, larger flow velocities are recorded over porous substrates. We argue that these are due to the presence of a longitudinal pressure gradient, which in turn is a consequence of the current mass loss. Its presence over the porous substrate is proved by the current interface longitudinal slope. However, other effects of the presence of the porous substrate, such as the relaxation of the no-slip boundary condition and the bed-normal momentum exchange, also affect the velocity field. The turbulent structure changes significantly over the porous substrate: while streamwise turbulence decreases, shear and bed-normal Reynolds stresses increase in large part of the current depth. Buoyancy instabilities further enhance the bed-normal momentum flux and, in the near-bed region, contribute to turbulent kinetic energy generation together with shear.
Jump phenomena in vortex-induced vibrations of a circular cylinder at a low Reynolds number
Authors: Shen Linwei , Sun Zhilin
Published: December 2019

The cross flow-induced vibrations of a circular cylinder at the Reynolds number of 150 are numerically investigated in a systematic manner in terms of a wide range of reduced velocity. The effect of the mass ratio on the cylinder behavior is studied, with three mass ratios, namely, 2, 10, and 50, being considered particularly in detail. The mass ratio is defined as the mass of the cylinder to the mass of the fluid it displaces. A sudden decrease in the vibration amplitude takes place at a certain value of the reduced velocity, accompanied by an abrupt increase in the lift coefficient and the vortex shedding frequency. The vortex shedding frequency at the upper end of the lock-in region is about 0.14 for all the mass ratios, which may mark the lower limit of the vortex shedding frequency at this Reynolds number. The jump phenomena may be ascribed to this limitation. Moreover, the vortex shedding frequency in the non-lock-in region varies slightly with the reduced velocity but is not approaching the Strouhal number for the stationary cylinder at the same Reynolds number. In fact, the frequency rises with the increasing mass ratio and reaches about 0.2 as the mass ratio is larger than 10. Besides, the vortex shedding mode does not remain “2S” for the mass ratio larger than 14 when the reduced velocity is increased to get into the non-lock-in region since the vortex shedding frequency is separate from the cylinder oscillation frequency.
Spatiotemporal dynamics of turbulent coaxial jet analyzed by symbolic information-theory quantifiers and complex-network approach
Authors: Kobayashi Wataru , Gotoda Hiroshi , Kandani Shuya , Ohmichi Yuya , Matsuyama Shingo
Published: December 2019

We numerically study the spatiotemporal dynamics of a turbulent coaxial jet in a model rocket engine combustor from the viewpoints of symbolic information-theory quantifiers and complex networks. The dynamic behavior of flow velocity undergoes a significant transition from a stochastic to chaotic state as the turbulent jet moves downstream. The small-world nature exists in the near field forming a stochastic state, whereas it disappears by the formation of a chaotic state in the far field. The dynamic behavior of hydrogen and oxygen concentrations in the far field also represents deterministic chaos. The simultaneous dynamic behavior with chaotic mixing forms the phase-synchronization state.
Critical concentrations of Zn and Mg for enhanced diamagnetism in Al-Zn-Mg alloys
Authors: Nishimura Katsuhiko , Matsuda Kenji , Tsuchiya Taiki , Nunomura Norio , Bendo Artenis , Isikawa Yosikazu , Imai Kosuke , Adachi Hiroki , Hutchison Wayne D.
Published: December 2019

Temperature and time dependences of the magnetization of Al-Zn-Mg alloys with varying Zn to Mg ratios (Zn/Mg = 0.25, 0.5, 1, 2, 5.5, and 9, keeping the total concentration of Zn plus Mg to be 5 at. %) were studied in the range from 10 to 310 K after various periods of natural aging. In particular, for Al1−y(Mg2Zn11)y alloys, the total concentrations of Zn and Mg were also varied from 2 to 20 at. % (y = 0.02, 0.03, 0.04, 0.05, 0.1, and 0.2). The largest time variant enhanced diamagnetism was observed for Al0.95(Mg2Zn11)0.05 as a result of solution heat treatment/quenching and natural aging. Isothermal measurements of magnetization vs time for natural aging temperatures from 260 to 300 K for Al0.95(Mg2Zn11)0.05 provided activation energies for solute clustering: 0.69 ± 0.05 eV (for stages I and II) and 0.78 ± 0.03 eV (for stages II and III). The mechanical hardness vs time at 273 K for Al0.95(Mg2Zn11)0.05 confirmed that the time variation of magnetization was related to the precipitation process of Zn/Mg/vacancy zones. Additionally, temperature dependences of the magnetization of Mg21Zn25, Mg4Zn7, MgZn2, and Mg2Zn11 were examined. The observed magnetization for the Mg-Zn compounds was found to be too small to account for the enhanced diamagnetic contributions to magnetization of Al-Zn-Mg alloys. A possible Zn-Mg-vacancy atomic arrangement responsible for the enhanced diamagnetism is discussed.
A theoretical model of the thermoelectric properties of SnSxSe1−x and how to further enhance its thermoelectric performance
Authors: Gupta Raveena , Kaur Baljinder , Carrete Jesús , Bera Chandan
Published: December 2019

Tin-based chalcogenides have a lot of potential as thermoelectric materials due to their ultralow thermal conductivity. Therefore, most reports on doped SnS focus on its power factor as the other condition for a high thermoelectric figure of merit (ZT). Here, we use the Boltzmann transport formalism to calculate both the power factor and the thermal conductivity for SnS, SnSe, and SnSxSe1−x and compare it with experimental measurements. Our theoretical model, based on a relaxation-time formalism, is in very good agreement with the reported values. We conclude that, while impurity scattering plays a major role in electron transport and, therefore, largely determines the power factor, alloy scattering is crucial for phonon transport. Specifically, alloying reduces the thermal conductivity of SnSe0.70S0.30 by a factor of ∼1.3 compared to SnSe and by a factor of ∼2 compared to SnS. This leads to ∼65% and ∼33% enhancements of ZT for p-type and n-type doping, respectively, at 800 K with respect to SnSe.
A 3D-printed microfluidic-enabled hollow microneedle architecture for transdermal drug delivery
Authors: Yeung Christopher , Chen Shawnus , King Brian , Lin Haisong , King Kimber , Akhtar Farooq , Diaz Gustavo , Wang Bo , Zhu Jixiang , Sun Wujin , Khademhosseini Ali , Emaminejad Sam
Published: December 2019

Embedding microfluidic architectures with microneedles enables fluid management capabilities that present new degrees of freedom for transdermal drug delivery. To this end, fabrication schemes that can simultaneously create and integrate complex millimeter/centimeter-long microfluidic structures and micrometer-scale microneedle features are necessary. Accordingly, three-dimensional (3D) printing techniques are suitable candidates because they allow the rapid realization of customizable yet intricate microfluidic and microneedle features. However, previously reported 3D-printing approaches utilized costly instrumentation that lacked the desired versatility to print both features in a single step and the throughput to render components within distinct length-scales. Here, for the first time in literature, we devise a fabrication scheme to create hollow microneedles interfaced with microfluidic structures in a single step. Our method utilizes stereolithography 3D-printing and pushes its boundaries (achieving print resolutions below the full width half maximum laser spot size resolution) to create complex architectures with lower cost and higher print speed and throughput than previously reported methods. To demonstrate a potential application, a microfluidic-enabled microneedle architecture was printed to render hydrodynamic mixing and transdermal drug delivery within a single device. The presented architectures can be adopted in future biomedical devices to facilitate new modes of operations for transdermal drug delivery applications such as combinational therapy for preclinical testing of biologic treatments.
Up-conversion superfluorescence induced by abrupt truncation of coherent field and plasmonic nanocavity
Authors: Hata Ryosuke , Yokoshi Nobuhiko , Ajiki Hiroshi , Ishihara Hajime
Published: December 2019

We theoretically propose a new method for generating up-converted coherent light from two-level systems (TLSs) coupled with a plasmonic nanocavity. The emission spectrum of a TLS excited by a strong laser exhibits a triplet structure called the Mollow triplet. If the lower Mollow sideband is tuned to the cavity mode energy, population inversion of a TLS occurs. When the driving laser is abruptly truncated under this condition, an up-converted photon is emitted from the TLSs. We also predict the up-converted superfluorescence from an ensemble of TLSs as a correlation effect among the excited states of the TLSs.
Equation of state for a chemically dissociative, polyatomic system: Carbon dioxide
Authors: Wu Christine J. , Young David A. , Sterne Philip A. , Myint Philip C.
Published: December 2019

A notorious challenge in high-pressure science is to develop an equation of state (EOS) that explicitly treats chemical reactions. For instance, many materials tend to dissociate at high pressures and temperatures where the chemical bonds that hold them together break down. We present an EOS for carbon dioxide (CO2) that allows for dissociation and captures the key material behavior in a wide range of pressure–temperature conditions. Carbon dioxide is an ideal prototype for the development of a wide-ranging EOS that allows for chemical-dissociation equilibria since it is one of the simplest polyatomic systems and because it is of great interest in planetary science and in the study of detonations. Here, we show that taking dissociation into account significantly improves the accuracy of the resulting EOS compared to other EOSs that either neglect chemistry completely or treat CO2 dissociation in a more rudimentary way.
A model for real time, in situ estimation of cesium coverage on metal substrate using infrared imaging under vacuum
Authors: Singh Pranjal , Bandyopadhyay Mainak
Published: December 2019

The present work is to develop an infra-red (IR) camera based in situ diagnostic tool for the determination of cesium (Cs) coverage suitable for ion source applications. Cs seeding is done to reduce the surface work function that enhances the surface assisted negative hydrogen ion production. The temporal Cs deposition on a metal surface (for, e.g., tungsten or molybdenum) follows Langmuir adsorption isotherm (LAI) kind of behavior. The surface temperature varies while the Cs deposition is reflected in the IR camera temperature measurements for a constant surface emissivity value. In this paper, a model on the relationship between Cs coverage in correlation with surface emissivity and temperature variation based on the theory of LAI is presented. A surface ionization probe (SIP) in the form of a cathode-anode assembly together with an IR camera viewing arrangement is designed to measure the Cs flux and the surface temperature simultaneously to test our model. In the present experiment, the Cs flux measurement using SIP is validated with a standard quartz crystal microbalance (QCM). The proposed model would be useful to correlate Cs coverage on plasma grid-like surface conditions under negative ion source relevant vacuum conditions.
Size-dependent static bending of flexomagnetic nanobeams
Authors: Zhang Nan , Zheng Shijie , Chen Dejin
Published: December 2019

The present paper presents a Bernoulli–Euler flexomagnetic (FM) nanobeam model, which considers the effects of flexomagneticity, piezomagneticity, and the surface elasticity. Differential control equations and corresponding magnetic boundary conditions are derived to investigate the influences of direct and converse FM couplings over the magnetic-elastic response. Size-dependent theoretical solutions for the static bending deformation of the cantilever, simply supported, and clamped nanobeams subjected to concentrated or uniformly distributed load are derived. Numerical simulations demonstrate that the flexomagneticity effect plays the role of the scale-dependent enhancement of the bending rigidity, which is independent of boundary conditions. But for the residual surface stresses, softening or stiffening the beam depends on boundary conditions.
Turbulence statistics and very-large-scale motions in decelerating open-channel flow
Authors: Zhang Peng , Duan Yanchong , Li Danxun , Hu Jiang , Li Wenjie , Yang Shengfa
Published: December 2019

This study experimentally examined the turbulent characteristics of decelerating open-channel flow based on particle imaging velocimetry measurement. The decelerating flow shows a similar velocity profile to that in uniform flow, but it exhibits greater turbulence intensity and Reynolds stress. Statistical evidence of the presence of very-large-scale motions (VLSMs) in decelerating open-channel flows was presented for the first time. The results indicate that VLSMs in decelerating flows can survive further away from the wall when compared to other wall-turbulence flows. The contribution rate of the VLSMs to the turbulent kinetic energy and the Reynolds stress in the decelerating open-channel flow is slightly lower than that in channels, boundary layers, and pipe flows.
Spin-flip excitations induced by dehydrogenation in a magnetic single-molecule junction
Authors: Wang Yu , Li Xiaoguang , Yang Jinlong
Published: December 2019

Recent scanning tunneling microscopy experiments on electron transport through iron(ii) phthalocyanine (FePc) molecules adsorbed on Au(111) surfaces have revealed that the measured differential conductance signals can be modulated through a selective dehydrogenation process [R. Li et al., Chem. Commun. 54, 9135 (2018)]. To understand the physical origin of the variation of line shapes in the measured dI/dV spectra, we employ a first-principles-based quantum transport simulation to calculate the electronic structures and transport properties in the dehydrogenated FePc/Au(111) composite system. Theoretical results indicate that the removal of eight outermost hydrogen atoms in the FePc molecule distorts the planar molecular conformation by increasing the distance between the Fe center and substrate and thus breaks the ligand field exerted on the Fe 3d orbitals. Such variations lead to a weaker coupling with the substrate along with a different local electronic configuration of the Fe center compared with that of the intact case, which is responsible for the suppression of Kondo resonance and the appearance of spin-flip excitation in the system. The simulated dI/dV plots are consistent with the experimental observations, showing the typical step features at finite bias associated with spin-flip excitations of a spin-1 quantum magnet. These findings provide important insights into the electron correlation effects modulated by the structural and chemical environment of the molecular spin center.
17O NMR as a measure of basicity of alkaline-earth oxide surfaces: A theoretical study
Authors: Maleki Farahnaz , Pacchioni Gianfranco
Published: December 2019

The surface basicity of the alkaline-earth metal oxides has been investigated by studying the properties of 17O nuclear magnetic resonance (NMR). To this end, we performed density functional theory calculations and determined the 17O chemical shift and the quadrupolar coupling constants of the regular and stepped surfaces of MO (M = Mg, Ca, Sr, and Ba) oxides. The computed average chemical shift (δisoav) for 17O NMR of bulk MgO, CaO, SrO, and BaO is 46, 301, 394, and 636 ppm, respectively, in excellent agreement with the experiment. The 17O NMR chemical shifts correlate linearly with the Madelung potential in the four oxides. Next, we considered the changes in the 17O chemical shift due to the adsorption of BR3 (R = F and OCH3) and pyrrole as probe molecules. We found that the 17O NMR signal of the O ion directly bound to the probe molecule shifts considerably compared to the clean surface. This is due to a change in the polarization of the O charge distribution due to the molecular adsorption. This change is the largest for BaO, with the strongest bond and the shortest surface-adsorbate distance, and the smallest for MgO, thus showing a direct correlation between 17O NMR and surface basicity. The 17O chemical shift of the basic site correlates linearly also with several properties of the adsorbed molecules, providing a direct measure of the surface basicity.
Laser direct printing of solder paste
Authors: Shan Yilin , Zhang Xianmin , Chen Gengchao , Li Hai
Published: December 2019

We experimentally demonstrated a laser-based approach for the maskless printing of solder paste with a predefined size and position. In this work, a 532 nm laser marking system is used to induce the formation of a solder paste bridge between the donor and acceptor substrate. After the donor is removed vertically, the bridge will rupture and a high aspect ratio voxel can be obtained on the acceptor substrate. The width and height of transferred voxels can be controlled by modifying the laser fluence. In order to find out the specific conditions for the solder paste bridge formation, we carried out transfer experiments at different gap distances and found out a bridge formation threshold. Solder paste bridges can be produced only when the gap distance is smaller than the threshold. Furthermore, the threshold can be affected by the film thickness and spot size. In this condition, a solder paste array with an average size of 100 µm and a pitch of 200 µm has been successfully transferred. Compared to conventional printing methods, the method proposed in this paper can effectively improve the transfer accuracy and reduce the production cost.