bluuebunny/crossref_metadata_2025 huggingface dataset:
Pathway-based network modeling finds hidden genes in shRNA screen for regulators of acute lymphoblastic leukemia
Authors: Wilson Jennifer L. , Dalin Simona , Gosline Sara , Hemann Michael , Fraenkel Ernest , Lauffenburger Douglas A.
Published: June 2016

We construct a pathway de novo for microenvironment-specific genetic regulators of acute lymphoblastic leukemia using RNAi screening, and mRNA data.
System optimization for determination of cobalt in biological samples by ICP-OES using photochemical vapor generation
Authors: Coutinho de Jesus Honerio , Grinberg Patricia , Sturgeon Ralph E.
Published: May 2016

An optimized photochemical vapor generation (PVG) approach for efficient synthesis of volatile cobalt species is described.
Arginine side-chain modification that occurs during copper-catalysed azide–alkyne click reactions resembles an advanced glycation end product
Authors: Conibear Anne C. , Farbiarz Karine , Mayer Rupert L. , Matveenko Maria , Kählig Hanspeter , Becker Christian F. W.
Published: June 2016

An adduct of dehydroascorbate with arginine forms during copper-catalysed azide–alkyne click reactions and resembles an advanced glycation end product.
A prototype reversible polymersome-stabilized H2S photoejector operating under pseudophysiological conditions
Authors: Tron A. , Peyret A. , Thevenot J. , Bofinger R. , Lecommandoux S. , McClenaghan N. D.
Published: June 2016

Polymersome capsules are shown to solubilise photolabile hydrosulfide-containing (2), as well as hydroxylated (1), malachite green derivatives in their leuco-forms in aqueous buffer solution.
Facile synthesis of diverse transition metal oxide nanoparticles and electrochemical properties
Authors: Zhang Hao , Wang Xiaofeng , Chen Chengcheng , An Cuihua , Xu Yanan , Dong Yanying , Zhang Qiuyu , Wang Yijing , Jiao Lifang , Yuan Huatang
Published: May 2016

Four diverse metal oxide nanoparticles are synthesized successfully and CoO nano-cubes show excellent electrochemical properties.
Controllable synthesis of VO2(D) and their conversion to VO2(M) nanostructures with thermochromic phase transition properties
Authors: Song Zhengdong , Zhang Liangmiao , Xia Fang , Webster Nathan A. S. , Song Jingchao , Liu Bin , Luo Hongjie , Gao Yanfeng
Published: June 2016

VO2(M) nanostructures with lower thermochromic phase transition temperature and narrower thermal hysteresis width were synthesized by a hydrothermal-calcination method, making them suitable candidates for smart windows.
Controlled synthesis of concentration gradient LiNi0.84Co0.10Mn0.04Al0.02O1.90F0.10 with improved electrochemical properties in Li-ion batteries
Authors: Chen Weihua , Li Yanyang , Zhao Juanjuan , Yang Feifei , Zhang Jianmin , Shi Qiuzhi , Mi Liwei
Published: June 2016

Ion exchange method is adopted to design the concentration gradient materials for Li-ion batteries.
Energy storage performance of Vn+1Cn monolayer as electrode material studied by first-principles calculations
Authors: Bai Lina , Yin Haitao , Zhang Xitian
Published: June 2016

Vn+1Cn monolayer is a promising candidate for electrode materials, due to high conductivity, large cation storage capabilities, and high-rate performance during the charging/discharging process.
Synthesis, characterization, organic compound degradation activity and antimicrobial performance of g-C3N4sheets customized with metal nanoparticles-decorated TiO2nanofibers
Authors: Adhikari Surya Prasad , Awasthi Ganesh Prasad , Lee Joshua , Park Chan Hee , Kim Cheol Sang
Published: June 2016

Here, we discuss for the first time a simple and direct approach to fabricate multifunctional silver nanoparticles decorated porous TiO2nanofibers interpolated on a thin and large g-C3N4sheet using a electrospinning–calcination process.
CO2 chemisorption in Li2CuO2 microstructurally modified by ball milling: study performed with different physicochemical CO2 capture conditions
Authors: Lara-García Hugo A. , Ramírez-Moreno Margarita J. , Ortiz-Landeros José , Pfeiffer Heriberto
Published: June 2016

Lithium cuprate (Li2CuO2) was obtained by a solid state reaction and a subsequent ball milling process. Then, the samples were characterized (structurally and microstructurally) and evaluated as CO2 captors.
Conductivity of composite membrane-based poly(ether-ether-ketone) sulfonated (SPEEK) nanofiber mats of varying thickness
Authors: Reyes-Rodriguez J. L. , Solorza-Feria O. , García-Bernabé A. , Giménez E. , Sahuquillo O. , Compañ V.
Published: May 2016

Nanofiber mats of SPEEK70wt%–PVB30wt%(polyvinyl butyral)-based composite membranes were prepared by varying the electrospinning time in order to obtain mats with different thicknesses.
Cu1.5Mn1.5O4spinel: a novel anode material for lithium-ion batteries
Authors: Quan Jingbin , Mei Lin , Ma Zheng , Huang Jichun , Li Decheng
Published: May 2016

A facile spray drying method has been developed for the synthesis of Cu1.5Mn1.5O4, a novel material for lithium-ion batteries, which exhibits excellent cyclic retention.
Aqueous chemical solution deposition of spinel Cu1.5Mn1.5O4 single layer films for solar selective absorber
Authors: Ma Pengjun , Geng Qingfen , Gao Xianghu , Yang Shengrong , Liu Gang
Published: June 2016

Herein, non-toxic, ample, and cheap water served as the solvent to dissolve Cu and Mn nitrate, chelating agent, and wetting agent, where a long-term stable sol solution could be easily obtained.
In situ study on the charge/discharge of nanocrystalline Li2C2 as a new cathode material
Authors: Li Yurong , Song Xiaoyan , Tang Fawei , Hou Chao , He Jiangtao , Wang Haibin , Liu Xuemei
Published: May 2016

The nanocrystalline Li2C2 has a high initial discharge capacity of 352 mA h g−1 and is promising as a new alloy-type cathode material.
Does halloysite behave like an inert carrier for doxorubicin?
Authors: Li Linlin , Fan Hailong , Wang Le , Jin Zhaoxia
Published: May 2016

Thermogravimetric analysis-mass spectrometry revealed more details of the interaction between doxorubicin and halloysite surface.
Novel synthesised flavone derivatives provide significant insight into the structural features required for enhanced anti-proliferative activity
Authors: Ravishankar Divyashree , Watson Kimberly A. , Greco Francesca , Osborn Helen M. I.
Published: June 2016

Synthesis and antiproliferative evaluation of a library of 76 methoxy and hydroxy flavones, and their 4-thio analogues showed that the novel thioflavones15fand16fexhibit 7–46 fold greater anti-proliferative potency than the natural flavone chrysin (2d).
Highly efficient removal of trace level dieldrin from water resources utilizing a cerasomal strategy
Authors: Feng Shanshan , Ma Fang , Liu Renfa , Li Shouzhu , Li Xiaoda , Jin Yushen , Fu Guanglei , Yue Xiuli
Published: May 2016

In this work, a novel cerasomal removal strategy for persistent organic pollutants (POPs) from water resources is proposed for the first time using the synchronous cerasome-forming process of an organic–inorganic composite lipid to capture and remove POPs.
Room temperature, air crystallized perovskite film for high performance solar cells
Authors: Dubey Ashish , Kantack Nicholas , Adhikari Nirmal , Reza Khan Mamun , Venkatesan Swaminathan , Kumar Mukesh , Khatiwada Devendra , Darling Seth , Qiao Qiquan
Published: May 2016

Room temperature growth and crystallization of perovskite nanorod films in ambient air without the use of thermal annealing was reported for high performance solar cells.
Novel donor–acceptor polymers containing o-fluoro-p-alkoxyphenyl-substituted benzo[1,2-b:4,5-b′]dithiophene units for polymer solar cells with power conversion efficiency exceeding 9%
Authors: Wang Ning , Chen Weichao , Shen Wenfei , Duan Linrui , Qiu Meng , Wang Junyi , Yang Chunming , Du Zhengkun , Yang Renqiang
Published: May 2016

A PCE of 9.02% for a two-dimensional polymer as donor applied in solar cells was obtained without any additive treatment.
Quinoxaline–thiophene based thick photovoltaic devices with an efficiency of ∼8%
Authors: Li Yuxiang , Ko Seo-Jin , Park Song Yi , Choi Hyosung , Nguyen Thanh Luan , Uddin Mohammad Afsar , Kim Taehyo , Hwang Sungu , Kim Jin Young , Woo Han Young
Published: May 2016

Three types of quinoxaline–thiophene based photovoltaic polymers were synthesized by considering the backbone coplanarityviaside-chain spacing and intrachain non-covalent coulombic interactions.
Ni–Co sulfide nanoboxes with tunable compositions for high-performance electrochemical pseudocapacitors
Authors: Xu Yangyang , Gao Xuehui , Chu Wenya , Li Quanguo , Li Tianjun , Liang Chengdu , Lin Zhan
Published: June 2016

We present facile syntheses of hollow Ni–Co sulfide nanoboxes with tunable compositions, i.e., NiCo2S4 and Ni2CoS4, as electrode materials for high-performance electrochemical pseudocapacitors, which are superior those of most of the Ni–Co sulfide electrodes reported before.
Adiponectin promotes VEGF-C-dependent lymphangiogenesis by inhibiting miR-27b through a CaMKII/AMPK/p38 signaling pathway in human chondrosarcoma cells
Authors: Huang Chun-Yin , Chang An-Chen , Chen Hsien-Te , Wang Shih-Wei , Lo Yuan-Shun , Tang Chih-Hsin
Published: June 2016

Chondrosarcoma is the second most frequently occurring type of bone malignancy characterized by distant metastatic propensity. Vascular endothelial growth factor-C (VEGF-C) is the major lymphangiogenic factor, and makes crucial contributions to tumour lymphangiogenesis and lymphatic metastasis. Adiponectin is a protein hormone secreted predominantly by differentiated adipocytes. In recent years, adiponectin has also been indicated as facilitating tumorigenesis, angiogenesis and metastasis. However, the effect of adiponectin on VEGF-C regulation and lymphangiogenesis in chondrosarcoma has remained largely a mystery. In the present study, we have shown a clinical correlation between adiponectin and VEGF-C, as well as tumour stage, in human chondrosarcoma tissues. We further demonstrated that adiponectin promoted VEGF-C expression and secretion in human chondrosarcoma cells. The conditioned medium from adiponectin-treated cells significantly induced tube formation and migration of human lymphatic endothelial cells. In addition, adiponectin knock down inhibited lymphangiogenesis in vitro and in vivo. We also found that adiponectin-induced VEGF-C is mediated by the calmodulin-dependent protein kinase II (CaMKII), AMP-activated protein kinase (AMPK) and p38 signaling pathway. Furthermore, the expression of miR-27b was negatively regulated by adiponectin via the CaMKII, AMPK and p38 cascade. The present study is the first to describe the mechanism of adiponectin-promoted lymphangiogenesis by up-regulating VEGF-C expression in chondrosarcomas. Thus, adiponectin could serve as a therapeutic target in chondrosarcoma metastasis and lymphangiogenesis.
Addressing Communicative Participation in Treatment Planning for Adults: A Survey of U.S. Speech-Language Pathologists
Authors: Torrence Janaki M. , Baylor Carolyn R. , Yorkston Kathryn M. , Spencer Kristie A.
Published: June 2016

Purpose

In speech-language pathology, there is increasing attention on participation-focused interventions to optimize participation in valued life roles. The purpose of this study was to investigate how speech-language pathologists (SLPs) in the United States address life participation in therapy programs, as well as their opinions regarding barriers and facilitators to participation-focused intervention.

Method

An online questionnaire presented case scenarios for aphasia, dysarthria, and laryngectomy to 66 SLPs who have worked with adults. SLPs were asked to write goals and describe therapy activities for the scenarios. The final section of the questionnaire was an open-ended question regarding barriers and facilitators to participation-focused intervention.

Results

Many SLPs addressed participation in their rationales for therapy; 50% of goals had a participation-focused rationale. However, the goals, activities, and outcomes measures typically focused more on impairment and skill performance. Only 8% of goals specifically referenced participation. Although many SLPs stated that participation-focused intervention is important, they identified many barriers to implementation including time and productivity constraints, limits of clinical settings, and documentation challenges.

Conclusions

There is potential for gaps between SLPs' participation-focused rationale for therapy and activities or outcomes measures that often do not include participation elements. SLPs are interested in participation-focused treatment resources.
Enhanced beam selection for multi‐user mm‐wave massive MIMO systems
Authors: Chen Jiaxuan , Zhao Peiyao , Wang Zhaocheng , Quan Jinguo
Published: May 2016

In millimetre wave (mm‐wave) communications, hybrid precoding is preferred which uses much less number of RF chains compared with the number of antenna elements. The conventional method selects the beamforming vectors at base station (BS) and the combining vectors at user equipments (UEs) to maximise the received signal power. However, in some specific scenarios, when UEs have strong and highly correlated paths, referred to as collided UEs, they might share the same beamforming vector at the BS leading to severe inter‐user interference. An enhanced beam selection algorithm is proposed to eliminate the severe inter‐user interference by reselecting the beamforming/combining vector pairs for the collided UEs. Simulation results demonstrate that the proposed scheme could increase the achievable rates of the collided UEs under sparse mm‐wave wireless channels.
Predictive over‐current protection scheme for step‐down DC–DC converter with emulated current mode control
Authors: Wang Langyuan , Zhao Menglian , Wu Xiaobo , Zhu Zhijie
Published: June 2016

A novel over‐current protection scheme for stepping down DC–DC converter with emulated current mode control is introduced. The proposed over‐current protection scheme overcomes an inherent lack of emulated current mode control, and can realise fast response and smooth control to over‐current events. The sample–hold technique is employed to generate adaptive reference for predictive current limit threshold. The scheme is verified by simulation and fabricated in 0.18 µm bipolar‐CMOS‐double‐diffused metal‐oxide‐semiconductor (DMOS) process.
Ambiguity function of Inmarsat BGAN signal for radar application
Authors: Lyu Xiaoyong , Stove Andrew , Gashinova Marina , Cherniakov Mikhail
Published: June 2016

The Inmarsat Broadband Global Area Network (BGAN) L‐band downlink signal from a radar viewpoint is studied. The signal is modelled and its ambiguity function (AF) is analysed and the AF is compared with that of the real recorded signal. It is shown that the AF of a single Inmarsat channel has an interference floor of −40 dB for 80 ms integration time. The AF of the Inmarsat BGAN signal is improved by combining multiple frequency channels with channel overlap.
Contrast enhancement using entropy‐based dynamic sub‐histogram equalisation
Authors: Parihar Anil Singh , Verma Om Prakash
Published: June 2016

This study presents a new contrast‐enhancement approach called entropy‐based dynamic sub‐histogram equalisation. The proposed algorithm performs a recursive division of the histogram based on the entropy of the sub‐histograms. Each sub‐histogram is divided recursively into two sub‐histograms with equal entropy. A stopping criterion is proposed to achieve an optimum number of sub‐histograms. A new dynamic range is allocated to each sub‐histogram based on the entropy and number of used and missing intensity levels in the sub‐histogram. The final contrast‐enhanced image is obtained by equalising each sub‐histogram independently. The proposed algorithm is compared with conventional as well as state‐of‐the‐art contrast‐enhancement algorithms. The quantitative results for a large image data set are statistically analysed using a paired t‐test. The quantitative and visual assessment shows that the proposed algorithm outperforms most of the existing contrast‐enhancement algorithms. The proposed algorithm results in natural‐looking, good contrast images with almost no artefacts.
Structural vibration quantification of micro wind turbine‐building system using a novel finite element analysis
Authors: Ren Bo
Published: June 2016

For turbine generated building vibration used in wind power industry, estimation of excitation/contact force at the connecting point between turbine and building structure is one of main concerns for Lab simulation of turbine. However, the Lab simulation method aiming at achieving both accurate simulation of working environment of turbine and the corresponding vibration level prediction/quantification of building response is not available so far. The direct force measurement method was investigated and found to be practically impossible in terms of operational accessibility. A method for indirectly determining interface contact force is proposed for Lab simulated, motor replaced, free stand wall mounted building vibration prediction. Power supply for driving the turbine and rotational speed automatic control of turbine for Lab simulation were determined by the proposed method. Furthermore, the establishments of suitable finite element models with their validation achieved good prediction results within acceptable error scales.
Ultrathin‐body tunnelling FET using a trench structure
Authors: Wang Ying , Wang Yan‐fu , Sun Ling‐ling , Xue Wei , Cao Fei
Published: June 2016

An ultrathin‐channel trench single gate tunnelling field‐effect transistor (trench SG‐TFET) with a 5 nm channel thickness is proposed and investigated. Trench SG‐TFETs demonstrate a higher ION (∼8 times), a steeper sub‐threshold swing (SS) (average SS of 46.2 mV/decade and point SS of 21.8 mV/decade), and a higher ION/IOFF current ratio (∼10 times) as compared with the conventional SG‐TFET at VDS = 0.4 V and temperature of 300 K. Also by using intrinsic region in drain, it has a strong immunity to short‐channel effects in extremely scaled trench SG‐TFETs. The proposed trench SG‐TFET seems to be attractive for future energy‐efficient circuit applications.
A pumping lemma for flip-pushdown languages
Authors: Kostolányi Peter
Published: June 2016

Flip-pushdown automata are pushdown automata with an extra ability to reverse the contents of the pushdown store. A generalisation of the pumping lemma for context-free languages is presented, which applies to the families of languages accepted by flip-pushdown automata with k pushdown flips, for an arbitrary constant k. The presented result gives rise to a new technique for disproving existence of flip-pushdown automata with a constant number of flips, which is significantly simpler compared to methods used for this purpose so far.
Decision algorithms for Fibonacci-automatic Words, I: Basic results
Authors: Mousavi Hamoon , Schaeffer Luke , Shallit Jeffrey
Published: June 2016

We implement a decision procedure for answering questions about a class of infinite words that might be called (for lack of a better name) “Fibonacci-automatic”. This class includes, for example, the famous Fibonacci word f = f0f1f2··· = 01001010··· , the fixed point of the morphism 0 → 01 and 1 → 0. We then recover many results about the Fibonacci word from the literature (and improve some of them), such as assertions about the occurrences in f of squares, cubes, palindromes, and so forth.
Porsche-Consulting-Studie: „Mancher hält Digitalisierung für Hype“
Authors: Kucera Martin
Published: May 2016

Porsche Consulting hat 60 Top-Manager deutscher Krankenhäuser online zum Thema Lean Hospital befragt. Im Gespräch mit kma erläutert Studienleiter Roman Hipp, warum es bei der Umsetzung an vielen Stellen hakt.
Software-Entwickler Comed: We are Family
Authors: Mau Jens
Published: May 2016

Familienbetriebe kommen gegen die Großen oft nicht an, immer häufiger fehlt ein Nachfolger. Ganz anders sieht es bei Comed aus, die jetzt 30-jähriges Jubiläum feiern.
Severe Thrombotic Complications in Congenital Afibrinogenemia: A Pathophysiological and Management Dilemma
Authors: Santoro Cristina , Massaro Fulvio , Venosi Salvatore , Capria Saveria , Baldacci Erminia , Foà Roberto , Mazzucconi Maria
Published: June 2016

Congenital afibrinogenemia (CA) is a disease characterized by a complex pathophysiology, involving both the procoagulant and fibrinolytic systems, as well as platelet activity. Although hemorrhagic diathesis represents the most frequent clinical presentation of this disorder, severe thrombotic events can occur. It is not yet clear if these events are strictly related to the disease itself or to the fibrinogen replacement therapy. Different hypotheses on the pathophysiological mechanisms have been proposed. It is well known that fibrinogen/fibrin has a role in the downregulation of thrombin generation in plasma. In the absence of circulating fibrinogen, this “antithrombin” activity is missing and plasma thrombin levels rise; this excess of thrombin could promote clotting of the infused fibrinogen, initiating the thrombotic process. Furthermore, the observation of impaired plasmin generation in the plasma of CA patients has raised the hypothesis of a fibrinolytic system deficiency. We report the case of a CA male patient who at the age of 36 years experienced an arterial thrombosis in his left lower limb. Despite an aggressive medical treatment with low-molecular-weight heparin, fibrinolytic and antiplatelet agents, the arterial thrombosis progressed to the obstruction of the whole left arterial district and the patient underwent the amputation of the left lower limb. This case demonstrates the complexity of pathophysiology and clinical management of a “so-called” bleeding disorder as CA.
Prophylaxis in von Willebrand Disease: Coming of Age?
Authors: Saccullo Giorgia , Makris Mike
Published: June 2016

Although in most cases von Willebrand disease (VWD) is a mild disorder, a subgroup of patients experience frequent bleeding. In contrast to severe hemophilia in which prophylaxis is the accepted standard of care, this is less frequently used in VWD. Most type 1 VWD patients can be adequately managed with episodic desmopressin and tranexamic acid. In patients with more severe disease, especially those with type 3 VWD, joint bleeds, epistaxis, menorrhagia, and gastrointestinal bleeding are problematic and usually require treatment with von Willebrand factor/factor VIII (VWF/FVIII) concentrate. While in the past these patients were managed with on-demand VWF/FVIII concentrate, several recent reports have demonstrated the value of prophylactic treatment. Despite some uncertainties about the economic impact of treatment of severe VWD, prophylaxis with VWF concentrate should now be considered as the standard of care for the more severe end of the spectrum of affected individuals. The recent introduction of recombinant VWF concentrate is likely to improve the acceptability of prophylaxis in VWD.
Reproducibility of the cutoff probe for the measurement of electron density
Authors: Kim D. W. , You S. J. , Kwon J. H. , You K. H. , Seo B. H. , Kim J. H. , Yoon J.-S. , Oh W. Y.
Published: June 2016

Since a plasma processing control based on plasma diagnostics attracted considerable attention in industry, the reproducibility of the diagnostics using in this application has become a great interest. Because the cutoff probe is one of the potential candidates for this application, knowing the reproducibility of the cutoff probe measurement becomes quit important in the cutoff probe application research. To test the reproducibility of the cutoff probe measurement, in this paper, a comparative study among the different cutoff probe measurements was performed. The comparative study revealed remarkable result: the cutoff probe has a great reproducibility for the electron density measurement, i.e., there are little differences among measurements by different probes made by different experimenters. The discussion including the reason for the result was addressed via this paper by using a basic measurement principle of cutoff probe and a comparative experiment with Langmuir probe.
Scaling law for bubbles rising near vertical walls
Authors: Dabiri Sadegh , Bhuvankar Pramod
Published: June 2016

This paper examines the rising motion of a layer of gas bubbles next to a vertical wall in a liquid in the presence of an upward flow parallel to the wall to help with the understanding of the fluid dynamics in a bubbly upflow in vertical channels. Only the region near the wall is simulated with an average pressure gradient applied to the domain that balances the weight of the liquid phase. The upward flow is created by the rising motion of the bubbles. The bubbles are kept near the wall by the lateral lift force acting on them as a result of rising in the shear layer near the wall. The rise velocity of the bubbles sliding on the wall and the average rise velocity of the liquid depend on three dimensionless parameters, Archimedes number, Ar, Eötvös number, Eo, and the average volume fraction of bubbles on the wall. In the limit of small Eo, bubbles are nearly spherical and the dependency on Eo becomes negligible. In this limit, the scaling of the liquid Reynolds number with Archimedes number and the void fraction is presented. A scaling argument is presented based on viscous dissipation analysis that matches the numerical findings. Viscous dissipation rates are found to be high in a thin film region between the bubble and the wall. A scaling of the viscous dissipation and steady state film thickness between the bubble and the wall with Archimedes number is presented.
Tunable angle absorption of hyperbolic metamaterials based on plasma photonic crystals
Authors: Jiao Zheng , Ning Renxia , Xu Yuan , Bao Jie
Published: June 2016

We present the design of a multilayer structure of hyperbolic metamaterials based on plasma photonic crystals which composed of two kinds of traditional dielectric and plasma. The relative permittivity of hyperbolic metamaterials has been studied at certain frequency range. The absorption and reflection of the multilayer period structure at normal and oblique incident have been investigated by the transfer matrix method. We discussed that the absorption is affected by the thickness of material and the electron collision frequency γ of the plasma. The results show that an absorption band at the low frequency can be obtained at normal incident angle and another absorption band at the high frequency can be found at a large incident angle. The results may be applied by logical gate, stealth, tunable angle absorber, and large angle filter.
A numerical approach for the direct computation of flows including fluid-solid interaction: Modeling contact angle, film rupture, and dewetting
Authors: Mahady K. , Afkhami S. , Kondic L.
Published: June 2016

In this paper, we present a computationally efficient method for including fluid-solid interactions into direct numerical simulations of the Navier–Stokes equations. This method is found to be as powerful as our earlier formulation [K. Mahady et al., “A volume of fluid method for simulating fluid/fluid interfaces in contact with solid boundaries,” J. Comput. Phys. 294, 243 (2015)], while outperforming the earlier method in terms of computational efficiency. The performance and efficacy of the presented method are demonstrated by computing contact angles of droplets at equilibrium. Furthermore, we study the instability of films due to destabilizing fluid-solid interactions, and discuss the influence of contact angle and inertial effects on film breakup. In particular, direct simulation results show an increase in the final characteristic length scales when compared to the predictions of a linear stability analysis, suggesting significant influence of nonlinear effects. Our results also show that emerging length scales differ, depending on a number of physical dimensions considered.
An unstructured mesh arbitrary Lagrangian-Eulerian unsteady incompressible flow solver and its application to insect flight aerodynamics
Authors: Su Xiaohui , Cao Yuanwei , Zhao Yong
Published: June 2016

In this paper, an unstructured mesh Arbitrary Lagrangian-Eulerian (ALE) incompressible flow solver is developed to investigate the aerodynamics of insect hovering flight. The proposed finite-volume ALE Navier-Stokes solver is based on the artificial compressibility method (ACM) with a high-resolution method of characteristics-based scheme on unstructured grids. The present ALE model is validated and assessed through flow passing over an oscillating cylinder. Good agreements with experimental results and other numerical solutions are obtained, which demonstrates the accuracy and the capability of the present model. The lift generation mechanisms of 2D wing in hovering motion, including wake capture, delayed stall, rapid pitch, as well as clap and fling are then studied and illustrated using the current ALE model. Moreover, the optimized angular amplitude in symmetry model, 45°, is firstly reported in details using averaged lift and the energy power method. Besides, the lift generation of complete cyclic clap and fling motion, which is simulated by few researchers using the ALE method due to large deformation, is studied and clarified for the first time. The present ALE model is found to be a useful tool to investigate lift force generation mechanism for insect wing flight.
Dynamic colloidal assembly pathways via low dimensional models
Authors: Yang Yuguang , Thyagarajan Raghuram , Ford David M. , Bevan Michael A.
Published: May 2016

Here we construct a low-dimensional Smoluchowski model for electric field mediated colloidal crystallization using Brownian dynamic simulations, which were previously matched to experiments. Diffusion mapping is used to infer dimensionality and confirm the use of two order parameters, one for degree of condensation and one for global crystallinity. Free energy and diffusivity landscapes are obtained as the coefficients of a low-dimensional Smoluchowski equation to capture the thermodynamics and kinetics of microstructure evolution. The resulting low-dimensional model quantitatively captures the dynamics of different assembly pathways between fluid, polycrystal, and single crystals states, in agreement with the full N-dimensional data as characterized by first passage time distributions. Numerical solution of the low-dimensional Smoluchowski equation reveals statistical properties of the dynamic evolution of states vs. applied field amplitude and system size. The low-dimensional Smoluchowski equation and associated landscapes calculated here can serve as models for predictive control of electric field mediated assembly of colloidal ensembles into two-dimensional crystalline objects.
Toward a W4-F12 approach: Can explicitly correlated and orbital-based ab initio CCSD(T) limits be reconciled?
Authors: Sylvetsky Nitai , Peterson Kirk A. , Karton Amir , Martin Jan M. L.
Published: June 2016

In the context of high-accuracy computational thermochemistry, the valence coupled cluster with all singles and doubles (CCSD) correlation component of molecular atomization energies presents the most severe basis set convergence problem, followed by the (T) component. In the present paper, we make a detailed comparison, for an expanded version of the W4-11 thermochemistry benchmark, between, on the one hand, orbital-based CCSD/AV{5,6}Z + d and CCSD/ACV{5,6}Z extrapolation, and on the other hand CCSD-F12b calculations with cc-pVQZ-F12 and cc-pV5Z-F12 basis sets. This latter basis set, now available for H–He, B–Ne, and Al–Ar, is shown to be very close to the basis set limit. Apparent differences (which can reach 0.35 kcal/mol for systems like CCl4) between orbital-based and CCSD-F12b basis set limits disappear if basis sets with additional radial flexibility, such as ACV{5,6}Z, are used for the orbital calculation. Counterpoise calculations reveal that, while total atomization energies with V5Z-F12 basis sets are nearly free of BSSE, orbital calculations have significant BSSE even with AV(6 + d)Z basis sets, leading to non-negligible differences between raw and counterpoise-corrected extrapolated limits. This latter problem is greatly reduced by switching to ACV{5,6}Z core-valence basis sets, or simply adding an additional zeta to just the valence orbitals. Previous reports that all-electron approaches like HEAT (high-accuracy extrapolated ab-initio thermochemistry) lead to different CCSD(T) limits than “valence limit + CV correction” approaches like Feller-Peterson-Dixon and Weizmann-4 (W4) theory can be rationalized in terms of the greater radial flexibility of core-valence basis sets. For (T) corrections, conventional CCSD(T)/AV{Q,5}Z + d calculations are found to be superior to scaled or extrapolated CCSD(T)-F12b calculations of similar cost. For a W4-F12 protocol, we recommend obtaining the Hartree-Fock and valence CCSD components from CCSD-F12b/cc-pV{Q,5}Z-F12 calculations, but the (T) component from conventional CCSD(T)/aug’-cc-pV{Q,5}Z + d calculations using Schwenke’s extrapolation; post-CCSD(T), core-valence, and relativistic corrections are to be obtained as in the original W4 theory. W4-F12 is found to agree slightly better than W4 with ATcT (active thermochemical tables) data, at a substantial saving in computation time and especially I/O overhead. A W4-F12 calculation on benzene is presented as a proof of concept.
VESPA: The vibrational spectrometer for the European Spallation Source
Authors: Fedrigo Anna , Colognesi Daniele , Bertelsen Mads , Hartl Monika , Lefmann Kim , Deen Pascale P. , Strobl Markus , Grazzi Francesco , Zoppi Marco
Published: June 2016

VESPA, Vibrational Excitation Spectrometer with Pyrolytic-graphite Analysers, aims to probe molecular excitations via inelastic neutron scattering. It is a thermal high resolution inverted geometry time-of-flight instrument designed to maximise the use of the long pulse of the European Spallation Source. The wavelength frame multiplication technique was applied to provide simultaneously a broad dynamic range (about 0-500 meV) while a system of optical blind choppers allows to trade flux for energy resolution. Thanks to its high flux, VESPA will allow the investigation of dynamical and in situ experiments in physical chemistry. Here we describe the design parameters and the corresponding McStas simulations.
Reactions of substituted benzene anions with N and O atoms: Chemistry in Titan’s upper atmosphere and the interstellar medium
Authors: Wang Zhe-Chen , Bierbaum Veronica M.
Published: June 2016

The likely existence of aromatic anions in many important extraterrestrial environments, from the atmosphere of Titan to the interstellar medium (ISM), is attracting increasing attention. Nitrogen and oxygen atoms are also widely observed in the ISM and in the ionospheres of planets and moons. In the current work, we extend previous studies to explore the reactivity of prototypical aromatic anions (deprotonated toluene, aniline, and phenol) with N and O atoms both experimentally and computationally. The benzyl and anilinide anions both exhibit slow associative electron detachment (AED) processes with N atom, and moderate reactivity with O atom in which AED dominates but ionic products are also formed. The reactivity of phenoxide is dramatically different; there is no measurable reaction with N atom, and the moderate reactivity with O atom produces almost exclusively ionic products. The reaction mechanisms are studied theoretically by employing density functional theory calculations, and spin conversion is found to be critical for understanding some product distributions. This work provides insight into the rich gas-phase chemistry of aromatic ion-atom reactions and their relevance to ionospheric and interstellar chemistry.
A cryogen-free low temperature scanning tunneling microscope capable of inelastic electron tunneling spectroscopy
Authors: Zhang Shuai , Huang Di , Wu Shiwei
Published: June 2016

The design and performance of a cryogen-free low temperature scanning tunneling microscope (STM) housed in ultrahigh vacuum (UHV) are reported. The cryogen-free design was done by directly integrating a Gifford-McMahon cycle cryocooler to a Besocke-type STM, and the vibration isolation was achieved by using a two-stage rubber bellow between the cryocooler and a UHV-STM interface with helium exchange gas cooling. A base temperature of 15 K at the STM was achieved, with a possibility to further decrease by using a cryocooler with higher cooling power and adding additional low temperature stage under the exchange gas interface. Atomically sharp STM images and high resolution dI/dV spectra on various samples were demonstrated. Furthermore, we reported the inelastic tunneling spectroscopy on a single carbon monoxide molecule adsorbed on Ag(110) surface with a cryogen-free STM for the first time. Being totally cryogen-free, the system not only saves the running cost significantly but also enables uninterrupted data acquisitions and variable temperature measurements with much ease. In addition, the system is capable of coupling light to the STM junction by a pair of lens inside the UHV chamber. We expect that these enhanced capabilities could further broaden our views to the atomic-scale world.
Stability and natural frequency of nonspherical mode of an encapsulated microbubble in a viscous liquid
Authors: Liu Yunqiao , Wang Qianxi
Published: June 2016

The dynamics of encapsulated microbubbles (EMBs) subject to an ultrasound wave have wide and important medical applications, including sonography, drug delivery, and sonoporation. The nonspherical shape oscillation of an EMB, termed as shape modes, is one of the core mechanisms of these applications and therefore its natural frequency is a fundamentally important parameter. Based on the linear stability theory, we show that shape modes of an EMB in a viscous Newtonian liquid are stable. We derive an explicit expression for the natural frequency of shape modes, in terms of the equilibrium radius of an EMB, and the parameters of the external liquid, coating, and internal gases. The expression is validated by comparing to the numerical results obtained from the dynamic equations of shape modes of an EMB. The natural frequency of shape modes shifts appreciably due to the viscosity of the liquid, and this trend increases with the mode number. The significant viscous effects are due to the no-slip condition for the liquid flow at the surface of an EMB. Our results show that when subject to an acoustic wave, the shape instability for an EMB is prone to appear if 2ωk/ωd = n, where ωk is the natural frequency of shape modes, ωd is the driving frequency of the acoustic wave, and n is a natural number. The effects of viscosity on the natural frequency is thus critical in setting the driving frequency of ultrasound to avoid or activate shape modes of EMBs, which should be considered in the applications of medical ultrasound.
Many-body interaction and deformation of the atomic electron shells in the lattice dynamics of compressed atomic cryocrystals
Authors: Troitskaya E. P. , Gorbenko Ie. Ie. , Pilipenko E. A.
Published: June 2016

The lattice dynamics of compressed atomic cryocrystals are based on ab initio quantum-mechanical theories of deformable and polarizable atoms (Tolpygo model), while taking into account the many-body interaction. The parameters of the three-particle interaction and deformation of the atomic electron shells, which are calculated in terms of the overlap integrals of atomic orbitals and their derivatives, have the same order of magnitude thus demonstrating that they must be considered in tandem. Accounting for the deformation effects of the electron shells in the dipole approximation when calculating phonon frequencies leads to a “softening” of the longitudinal modes at points L and X, for an entire series of Ne-Xe crystals, and of the transverse modes in the directions Σ and Λ for Xe, under high compression. It is shown that it impossible to adequately reproduce the observed deviation from the Cauchi relation δ(p) for compressed atomic cryocrystals, without accounting for the deformation of electron shells of atoms in a quadrupole approximation. The inputs from a three-particle and quadrupole interaction for Ne, Kr, and Xe crystals are mutually compensated, which provides a weak dependence on pressure for δ(p). We found a good agreement between the calculated phonon frequencies, Birch and Fuchs elastic moduli, the deviation from the Cauchi relation for the total number of Ne-Xe crystals in a wide range of pressures, and existing experiments.
Thermal and quantum phase slips in niobium-nitride nanowires based on suspended carbon nanotubes
Authors: Masuda Kohei , Moriyama Satoshi , Morita Yoshifumi , Komatsu Katsuyoshi , Takagi Tasuku , Hashimoto Takayuki , Miki Norihisa , Tanabe Takasumi , Maki Hideyuki
Published: May 2016

Superconducting nanowires have attracted considerable attention due to their unique quantum-mechanical properties, as well as their potential as next-generation quantum nanodevices, such as single-photon detectors, phase-slip (PS) qubits, and other hybrid structures. In this study, we present the results of one-dimensional (1D) superconductivity in nanowires fabricated by coating suspended carbon nanotubes with a superconducting thin niobium nitride (NbN) film. In the resistance-temperature characteristic curves, hallmarks of 1D superconductivity with PS events are observed with unconventional negative magnetoresistance. We also confirm that a crossover occurs between thermal and quantum PSs as the temperature is lowered.
Three-dimensional nanostructures on Ge/Si(100) wetting layers: Hillocks and pre-quantum dots
Authors: Ramalingam Gopalakrishnan , Floro Jerrold A. , Reinke Petra
Published: May 2016

The annealing of sub-critical Ge wetting layers (WL < 3.5 ML) initiates the formation of 3D nanostructures, whose shape and orientation is determined by the WL thickness and thus directly related to the strain energy. The emergence of these nanostructures, hillocks and pre-quantum dots, is studied by scanning tunneling microscopy. A wetting layer deposited at 350 °C is initially rough on the nanometer length-scale and undergoes a progressive transformation and smoothening during annealing at T < 460 °C when vacancy lines and the 2xn reconstruction are observed. The metastable Ge WL then collapses to form 3D nanostructures whose morphology is controlled by the WL thickness: first, the hillocks, with a wedding cake-type structure where the step edges run parallel to the ⟨110⟩ direction, are formed from thin wetting layers, while {105}-faceted structures, called pre-quantum dots (p-QDs), are formed from thicker layers. The wetting layer thickness and thus the misfit strain energy controls the type of structure. The crossover thickness between the hillock and p-QDs regime is between 1.6 and 2.1 ML. The hillocks have larger lateral dimensions and volumes than p-QDs, and the p-QDs are exceptionally small quantum dots with a lower limit of 10 nm in width. Our work opens a new pathway to the control of nanostructure morphology and size in the elastically strained Ge/Si system.
Electrical and electroluminescent characterization of nanometric multilayers of SiOX/SiOY obtained by LPCVD including non-normal emission
Authors: Alarcón-Salazar J. , Zaldívar-Huerta I. E. , Aceves-Mijares M.
Published: June 2016

This work describes the analysis and fabrication by Low Pressure Chemical Vapor Deposition of two light-emitting capacitors (LECs) constituted by nanometric multilayers of silicon-rich oxide. For both structures, seven layers were used: three light emitting layers with 6% silicon excess and four conductive layers with 12% silicon excess for one LEC and the other with 14% silicon excess. Both LECs were annealed at 1100 °C. Both multilayers demonstrate a substantially improved photoluminescent response compared to single emitting layers. A dielectric constant of 4.1 and a trap density of 1016 cm−3 were obtained from capacitance-voltage curves. Analysis of current-voltage and electroluminescence-voltage (EL-V) characteristics indicates that EL initiates under the space-charge-limited current mechanism, and the required voltage to turn on the emission is 38 V which is the trap-free limit voltage. However, EL increases exponentially under the impact ionization and trap-assisted tunneling conduction mechanisms. The electroluminescence spectra for both multilayers show two emission peaks centered in 450 and 700 nm attributed to oxygen defects. Also, the LEC non-normal emission was measured and it behaves like a Lambertian optical source. Both multilayers obtain the values of efficiency in the order of 10−6 which is in good agreement with the values reported in the literature.
Accurate measurement of Seebeck coefficient
Authors: Liu Jian , Zhang Yacui , Wang Zhen , Li Maokui , Su Wenbin , Zhao Minglei , Huang Shengli , Xia Shengqing , Wang Chunlei
Published: June 2016

In this work, it was investigated how to measure Seebeck coefficient accurately. The offset voltages, between the specimen and measurement wires, might influence the results measured significantly and should be eliminated during measuring process. They do not depend on temperature difference but on temperature and include two parts: the intrinsic component related to the materials and the random one related to the contact. The inversion method could eliminate the offset voltages more accurately than the traditional differential methods, and thus measure Seebeck coefficient more accurately. The accuracy of Seebeck coefficient measurement could be further improved by performing a proper temperature difference, optimizing temperature control, and using an electromagnetic screen. The most accurate results were obtained with a standard deviation of 0.06 μV/K, measured under temperature difference of 1 K, temperature variation of 0.002 K, and with an iron electromagnetic screen.
Scanning thermal microscopy based on a quartz tuning fork and a micro-thermocouple in active mode (2ω method)
Authors: Bontempi Alexia , Nguyen Tran Phong , Salut Roland , Thiery Laurent , Teyssieux Damien , Vairac Pascal
Published: June 2016

A novel probe for scanning thermal microscope using a micro-thermocouple probe placed on a Quartz Tuning Fork (QTF) is presented. Instead of using an external deflection with a cantilever beam for contact detection, an original combination of piezoelectric resonator and thermal probe is employed. Due to a non-contact photothermal excitation principle, the high quality factor of the QTF allows the probe-to-surface contact detection. Topographic and thermal scanning images obtained on a specific sample points out the interest of our system as an alternative to cantilevered resistive probe systems which are the most spread.
Chaotic micromixer utilizing electro-osmosis and induced charge electro-osmosis in eccentric annulus
Authors: Feng Huicheng , Wong Teck Neng , Che Zhizhao , Marcos
Published: June 2016

Efficient mixing is of significant importance in numerous chemical and biomedical applications but difficult to realize rapidly in microgeometries due to the lack of turbulence. We propose to enhance mixing by introducing Lagrangian chaos through electro-osmosis (EO) or induced charge electro-osmosis (ICEO) in an eccentric annulus. The analysis reveals that the created Lagrangian chaos can achieve a homogeneous mixing much more rapidly than either the pure EO or the pure ICEO. Our systematic investigations on the key parameters, ranging from the eccentricity, the alternating time period, the number of flow patterns in one time period, to the specific flow patterns utilized for the Lagrangian chaos creation, present that the Lagrangian chaos is considerably robust. The system can obtain a good mixing effect with wide ranges of eccentricity, alternating time period, and specific flow patterns utilized for the Lagrangian chaos creation as long as the number of flow patterns in one time period is two. As the electric field increases, the time consumption for homogenous mixing is reduced more remarkably for the Lagrangian chaos of the ICEO than that of the EO.