bluuebunny/crossref_metadata_2025 huggingface dataset:
Nano vs. bulk rutile TiO2:N,F in Z-scheme overall water splitting under visible light
Authors: Miyoshi Akinobu , Kato Kosaku , Yokoi Toshiyuki , Wiesfeld Jan J. , Nakajima Kiyotaka , Yamakara Akira , Maeda Kazuhiko
Published: June 2020

Nitrogen/fluorine-codoped rutile TiO2 nanoparticles worked more efficiently as a water oxidation photocatalyst in visible-light Z-scheme water splitting than a bulk analogue.
Tuning electrochemical and transport processes to achieve extreme performance and efficiency in solid oxide cells
Authors: Park Beom-Kyeong , Scipioni Roberto , Zhang Qian , Cox Dalton , Voorhees Peter W. , Barnett Scott A.
Published: June 2020

A new SOC that utilizes a very thin GDC/YSZ bi-layer electrolyte, support with enhanced porosity, and electrode surface modification via PrOx and GDC nanocatalysts pushes the limits of cell polarizations, exceeding fuel cell power density ∼3 W cm−2 and electrolysis current density ∼4 A cm−2.
A graphene oxide-aided triple helical aggregation-induced emission biosensor for highly specific detection of charged collagen peptides
Authors: Sun Xiuxia , Qiao Yan , Li Wenhua , Sui Yiyao , Ruan Yiyan , Xiao Jianxi
Published: June 2020

A graphene oxide-aided triple helical aggregation-induced emission biosensor provides a highly specific sensing platform for charged collagen peptides.
Exploring the inner environment of protein hydrogels with fluorescence spectroscopy towards understanding their drug delivery capabilities
Authors: Nandi Ramesh , Yucknovsky Anna , Mazo Manuel M. , Amdursky Nadav
Published: June 2020

Time-resolved fluorescence have used to explore the inner surface and solvation dynamics within protein hydrogels assisting in rationalizing their drug binding and release capabilities.
Gradient porous PNIPAM-based hydrogel actuators with rapid response and flexibly controllable deformation
Authors: Liu Jian , Xu Weizhong , Kuang Zhongwen , Dong Pengli , Yao Youxing , Wu Huaping , Liu Aiping , Ye Fangmin
Published: June 2020

Gradient PNIPAM-based intelligent hydrogels with bidirectional bending properties can realize flexibly controllable deformation and activity as soft actuators.
Continuous dry–wet spinning of white, stretchable, and conductive fibers of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) and ATO@TiO2 nanoparticles for wearable e-textiles
Authors: Gao Chunxia , He Sisi , Qiu Longbin , Wang Mingxu , Gao Jiefeng , Gao Qiang
Published: June 2020

Stretchable electronic textiles are urgently called for due to the emergence of next generation wearable electronics that can undergo various mechanical deformations that exist almost everywhere in our daily lives.
Near-infrared absorbing pyrrolopyrrole aza-BODIPY-based donor–acceptor polymers with reasonable photoresponse
Authors: Feng Ru , Sato Narumi , Nomura Mayuka , Saeki Akinori , Nakanotani Hajime , Adachi Chihaya , Yasuda Takuma , Furuta Hiroyuki , Shimizu Soji
Published: June 2020

Designing near-infrared (NIR) absorbing donor–acceptor (D–A) polymers with photoresponse beyond 900 nm has remained a challenge in the area of organic photovoltaics (OPV) owing to the limited kinds of strong electron acceptors.
Synthesis of nonlinear optical chromophores with isophorone-derived bridges for enhanced thermal stability and electro-optic activity
Authors: Liu Fenggang , Mo Songmin , Zhai Zhaofen , Peng Meishan , Wu Shuangke , Li Chunling , Yu Canwen , Liu Jianpeng
Published: June 2020

In this work, we developed a series of nonlinear optical chromophoresJ1–J4with the same julolidinyl-based donor and tricyanovinyldihydrofuran acceptor with different modified isophorone-derived bridges.
Carbon dot-dispersed hexabutyloxytriphenylene discotic mesogens: structural, morphological and charge transport behavior
Authors: Mahesh Pruthvi , Shah Asmita , Swamynathan K. , Singh Dharmendra Pratap , Douali Redouane , Kumar Sandeep
Published: June 2020

Triphenylene core-grafted 2,3,6,7,10,11-hexabutyloxytriphenylene (HAT4) discotic mesogens were synthesized and their composite matrices have been prepared by dispersing different concentrations of carbon dots (C-dots).
Revealable photonic prints with oppositely responsive polymers for improved visual sensing
Authors: Jia Lizhen , Li Miaomiao , Jiang Lixin , Gao Haoqiang , Tan Haiying , Peng Bolun , Xu Jiangping , Zhang Lianbin , Zhu Jintao
Published: June 2020

Revealable photonic prints are achieved by patterning photonic hydrogels with two oppositely pH responsive polymers. The shifting of colors in the patterned and background regions in the opposite directions improves the visibility for pH-sensing.
The conversion of nanocellulose into solvent-free nanoscale liquid crystals by attaching long side-arms for multi-responsive optical materials
Authors: Cheng Qiaoyun , Chen Pan , Ye Dongdong , Wang Junmei , Song Guangjie , Liu Junjie , Chen Zhiquan , Chen Lingyun , Zhou Qi , Chang Chunyu , Zhang Lina
Published: June 2020

Solvent-free nanoscale liquid crystals, featuring nanocellulose as the stiff core and long side-arms as the soft shell, showed unique flowability and responsiveness.
Identification of an unknown frameshift variant of NOG in a Han Chinese family with proximal symphalangism
Authors: Yuan Zhuang-Zhuang , Yu Fang , Jin Jie-Yuan , Jiao Zi-Jun , Tang Ju-Yu , Xiang Rong
Published: June 2020

Proximal symphalangism (SYM1) is an autosomal dominant disorder manifested by ankylosis of the proximal interphalangeal joints of fingers, carpal and tarsal bone fusion, and conductive hearing loss in some cases. Herein, we clinically diagnosed a Chinese patient with fusions of the bilateral proximal interphalangeal joints in the 2–5 digits without conductive hearing loss. Family history investigation revealed that his mother and grandfather also suffered from SYM1. Whole exome sequencing was performed to detect the genetic lesion of the family. The candidate gene variants were validated by Sanger sequencing. By data filtering, co-segregation analysis and bioinformatics analysis, we highly suspected that an unknown heterozygous frameshift variant (c.635_636insG, p.Q213Pfs*57) in NOG was responsible for the SYM1 in the family. This variant was predicted to be deleterious and resulted in a prolonged protein. This finding broadened the spectrum of NOG mutations associated with SYM1 and contributed to genetic diagnosis and counseling of families with SYM1.
BMP9 exhibits dual and coupled roles in inducing osteogenic and angiogenic differentiation of mesenchymal stem cells
Authors: Xiao Haozhuo , Wang Xiaoyu , Wang Claire , Dai Guangming , Zhu Zhenglin , Gao Shengqiang , He Baicheng , Liao Junyi , Huang Wei
Published: June 2020

Bone morphogenetic protein (BMP) 9 (BMP9) is one of most potent BMPs in inducing osteogenic differentiation of mesenchymal stem cells (MSCs). Recently, evidence has shown that osteogenesis and angiogenesis are coupled, however, it is unclear whether BMP9 induces MSC differentiation into endothelial-like cells and further promotes blood vessel formation. In the present study, we explored the potential of BMP9-induced angiogenic differentiation of MSCs, and the relationship between BMP9-induced osteogenic and angiogenic differentiation of MSCs. Osteogenic activities and angiogenic differentiation markers were analyzed at mRNA and protein levels. In vivo osteogenic and angiogenic differentiation of MSCs were tested by the ectopic bone formation model. We identified that adenoviral vectors effectively transduced in immortalized mouse embryonic fibroblasts (iMEFs) and expressed BMP9 with high efficiency. We found that BMP9 induces early and late osteogenic differentiation, and it up-regulated osteogenic marker expression in MSCs. Meanwhile, BMP9 induces angiogenic differentiation of MSCs via the expression of vascular endothelial growth factor a (VEGFa) and CD31 at both mRNA and protein levels. CD31-positive cells were also increased with the stimulation of BMP9. The ectopic bone formation tests found that BMP9-induced trabecular bone formation was coupled with the expression of blood vessel formation markers and sinusoid capillary formation. These findings suggest that BMP9 exhibits dual and coupled roles in inducing osteogenic and angiogenic differentiation of MSCs.
Spanish Pediatric Picture Identification Test
Authors: Mendel Lisa Lucks , Pousson Monique A. , Bass Johnnie K. , Coffelt Jordan Alyse , Morris Melanie , Lane Kati A.
Published: June 2020

Purpose

The purpose of this study was to construct and validate a recorded word recognition test for monolingual Spanish-speaking children utilizing a picture board and a picture-pointing task.

Design

The Spanish Pediatric Picture Identification Test was developed and validated in this study. Test construction steps included (a) producing new digital recordings of word lists created by Comstock and Martin (1984) using a bilingual Spanish–English female, (b) obtaining list equivalency, (c) creating digitally illustrated pictures representing the word lists, (d) validating the pictures using monolingual Spanish-speaking and bilingual Spanish–English children, and (e) re-establishing list equivalency and obtaining performance–intensity functions using a picture-pointing task with monolingual Spanish-speaking children and bilingual Spanish–English adults.

Results

Normative data for three Spanish word recognition lists were established. Performance–intensity functions at sensation levels from 0 to 40 dB SL in 8-dB steps were obtained, establishing list equivalency for Lists 1, 2, and 3.

Conclusions

The Spanish Pediatric Picture Identification Test was developed and validated as a picture-pointing task for word recognition with monolingual Spanish-speaking children. The two validated channel recordings include an English translation for ease of testing by clinicians lacking Spanish language skills. Future validation will be conducted with bilingual Spanish–English children with normal hearing and with hearing loss.
Intraoperative Awakening from Endotracheal General Anesthesia for Brain Mapping with Tracheal Tube In Situ
Authors: Bithal Parmod K. , Abdalla Shahenda S. , Jan Ravees , Ward Vandan D.
Published: June 2020

Awake craniotomy (AC) is indicated to excise a lesion close to an eloquent area of the brain. Success of this procedure depends upon the patient’s active participation during the awake phase of the surgery, especially for brain mapping. Occasionally, a patient may refuse to remain awake during the surgical procedure and demand general anesthesia (GA). A 27-year-old male with uncontrolled seizures from recurrent brain tumor near motor area refused to consent for AC citing his past unpleasant experience; so, the decision to administer GA was taken. To avoid straining/coughing on tracheal tube, his airway was anesthetized with transtracheal xylocaine, bilateral superior laryngeal nerve block, and inflation of tracheal tube cuff with xylocaine. GA was maintained with sevoflurane, infusion of fentanyl, and rocuronium. To awaken him, anesthetics were discontinued and rocuronium antagonized with sugammadex. Intravenous lignocaine and midazolam were administered to supress cough reflex and produce amnesia, respectively. He tolerated the entire duration of 30 minutes of brain mapping with electrocorticography and neurological testing comfortably. Upon completion of brain mapping, GA was reintroduced and the lesion excised. The surgical outcome was good with no neurological deficit. When interviewed postoperatively, the patient had no recall of the awake phase.
Associations between Features of External Ventricular Drain Management, Disposition, and Shunt Dependence
Authors: Engel Corey , Faulkner Amanda L. , Van Wyck David W. , Zomorodi Ali R. , King Nicolas K. Kam , Williamson Taylor Rachel A. , Hailey Claire E. , Umeano Odera A. , McDonagh David L. , Li Yi-Ju , James Michael L. ,   for the Duke Critical Care Outcomes Research Endeavors (C-CORE) group
Published: June 2020

Background In the United States, nearly 25,000 patients annually undergo percutaneous ventriculostomy for the management of increased intracranial pressure with little consensus on extraventricular drain management. To characterize relationships between external ventricular drain management, permanent ventriculoperitoneal shunt placement, and hospital disposition, we hypothesized that patients requiring extended drainage would have greater association with ventriculoperitoneal shunt placement and unfavorable disposition.

Methods Adult patients admitted to the Duke University Hospital Neuroscience Intensive Care Unit between 2008 and 2010 with extraventricular drains were analyzed. A total of 115 patient encounters were assessed to determine relative impact of age, sex, days of extraventricular placement, weaning attempts, cerebrospinal fluid drainage volumes, Glasgow Coma Scale, and physician’s experience on disposition at discharge and ventriculoperitoneal shunt placement. Univariate logistic regression was first used to test the effect of each variable on the outcome, followed by backward selection to determine a final multivariable logistic regression. Variables in the final model meeting p < 0.05 were declared as significant factors for the outcome.

Results Increased extraventricular drain duration (odds ratio [OR] = 1.17, confidence interval [CI] = 1.05–1.30, p = 0.0049) was associated with ventriculoperitoneal shunt placement, while older age (OR = 1.05, CI = 1.02–1.08, p = 0.0027) and less physician extraventricular drain management experience (OR = 4.04, CI = 1.67–9.79, p = 0.0020) were associated with unfavorable disposition.

Conclusion In a small cohort, exploratory analyses demonstrate potentially modifiable factors are associated with important clinical outcomes. These findings warrant further study to refine how such factors affect patient outcomes.
Management of Portal and Mesenteric Venous Thrombosis
Authors: Turkeltaub Joshua A. , Kriss Michael
Published: June 2020

Portal vein thrombosis is a rare condition seen in the general population, though is more prevalent in certain populations with thrombophilia as well as in patients with cirrhosis. Because morbidity and mortality can be significant with portal vein thrombosis, diagnosis and appropriate management are crucial. In noncirrhotic patients, untreated portal vein thrombosis can result in mesenteric ischemia and complications of portal hypertension. In cirrhosis, portal vein thrombosis is often incidentally found on routine screening imaging, and the treatment outside of transplant candidates is more controversial. In this review, we will outline risk factors for portal vein thrombosis, discuss indications for treatment, and evaluate both pharmacological and endovascular treatment options, highlighting unique clinical considerations dependent on the presence or absence of cirrhosis.
Exposure to Anticholinergic Medications in Pediatric Severe Sepsis and Feasibility of Delirium Screening
Authors: Madden Kate , Callif Charles G. , Tasker Robert C.
Published: June 2020

In sepsis, anticholinergic dysregulation may result in encephalopathy or delirium during severe illness, either as a result of central inflammation or because of exposure to medications with anticholinergic activity. In this retrospective study, we determined the magnitude of anticholinergic drug exposure in 75 children with severe sepsis. We found that exposure over the first 5 days was high—median (interquartile range) daily anticholinergic drug scale score 4 (2–5)—and associated with higher vasoactive scores and death. We conclude that anticholinergic drug exposure is significant in severe sepsis, which means it may be a modifiable factor that should be studied further.
Management of Refractory Epilepsy
Authors: Singh Rajveer , Chakravarty Kamalesh , Baishya Jitupam , Goyal Manoj K. , Kharbanda Parampreet
Published: June 2020

Drug refractory epilepsy, defined as a failure of adequate trials of two (or more) tolerated, appropriately chosen, and appropriately used antiepileptic drug (AED) regimens (whether administered as monotherapies or in combination) to achieve freedom from seizures, affects approximately 30% of patients with new-onset epilepsy. Persistent epileptic seizures in these patients, in addition to having deleterious effects on health, are also associated with psychosocial, behavioral, cognitive, and financial consequences. Despite availability of several new drugs, response to therapy remains poor in most of drug refractory cases. Also despite several ongoing treatment trials, ideal combination of AEDs remains to be identified. Careful attention to ruling out alternative diagnoses, optimal selection of AEDs, rational use of combination therapy, as well as attention to patient-specific factors, such as poor compliance and drug abuse, remain cornerstone of therapy. In view of poor response to polytherapy, if possible, surgical intervention should be contemplated early. In future, development of new drugs with better efficacy and tolerability and minimal drug interactions, as well as better nonpharmacological therapeutic techniques, will help in managing these patients better.
Bandgap-tunable device realized by ternary plasma photonic crystals arrays
Authors: Zhang Weidong , Wang Haitao , Zhao Xiaolin , Lan Weixia
Published: June 2020

We reported a bandgap-tunable device with ternary plasma photonic crystals (PPCs), achieving tunable bandgap for controlling the propagation of free-space electromagnetic waves from 11.5 GHz to 14.5 GHz. The device is designed as a square crystal structure composing ternary PPCs arrays. Both simulation and experimental results indicate that the transmission of the electromagnetic waves can be controlled by changing the plasma frequency, dielectric constant, and structure spacing in the device, realizing the dynamic adjustment of photonic bandgap bandwidth and center frequency. In addition, the plasma frequency was measured, which is consistent with the simulation results. Our strategy can be applied to design a variety of devices, including reconfigurable antennas, plasma lenses, and military-developed stealth equipment.
Geometric optimization of plasmonic nanostructure arrays on MWIR HgCdTe (MCT)
Authors: Vanamala Nagendrababu , Santiago Kevin C. , Das Naresh C. , Hargrove S. Keith
Published: June 2020

Mercury Cadmium Telluride (MCT) is a primary absorber material used in most infrared (IR) detection technologies. Our previous studies show that the optical absorbance profile of MCT in the mid-infrared region can be enhanced by 13% under ambient conditions via integrating periodic Indium Tin Oxide (ITO) nanostructures. Here, we focus on the geometrical parameterization and optimization of ITO nanostructure arrays. We simulate several types of geometries, their corresponding effective absorption profiles, E-field distribution, and optimal geometric parameters. This work may lead to improved light collection and absorption edge engineering, as MCT continues to be the material of choice in IR detection architectures.
Exploring the light-induced dynamics in solvated metallogrid complexes with femtosecond pulses across the electromagnetic spectrum
Authors: Naumova Maria A. , Kalinko Aleksandr , Wong Joanne W. L. , Alvarez Gutierrez Sol , Meng Jie , Liang Mingli , Abdellah Mohamed , Geng Huifang , Lin Weihua , Kubicek Katharina , Biednov Mykola , Lima Frederico , Galler Andreas , Zalden Peter , Checchia Stefano , Mante Pierre-Adrien , Zimara Jennifer , Schwarzer Dirk , Demeshko Serhiy , Murzin Vadim , Gosztola David , Jarenmark Martin , Zhang Jianxin , Bauer Matthias , Lawson Daku Max Latevi , Khakhulin Dmitry , Gawelda Wojciech , Bressler Christian , Meyer Franc , Zheng Kaibo , Canton Sophie E.
Published: June 2020

Oligonuclear complexes of d4–d7 transition metal ion centers that undergo spin-switching have long been developed for their practical role in molecular electronics. Recently, they also have appeared as promising photochemical reactants demonstrating improved stability. However, the lack of knowledge about their photophysical properties in the solution phase compared to mononuclear complexes is currently hampering their inclusion into advanced light-driven reactions. In the present study, the ultrafast photoinduced dynamics in a solvated [2 × 2] iron(II) metallogrid complex are characterized by combining measurements with transient optical-infrared absorption and x-ray emission spectroscopy on the femtosecond time scale. The analysis is supported by density functional theory calculations. The photocycle can be described in terms of intra-site transitions, where the FeII centers in the low-spin state are independently photoexcited. The Franck–Condon state decays via the formation of a vibrationally hot high-spin (HS) state that displays coherent behavior within a few picoseconds and thermalizes within tens of picoseconds to yield a metastable HS state living for several hundreds of nanoseconds. Systematic comparison with the closely related mononuclear complex [Fe(terpy)2]2+ reveals that nuclearity has a profound impact on the photoinduced dynamics. More generally, this work provides guidelines for expanding the integration of oligonuclear complexes into new photoconversion schemes that may be triggered by ultrafast spin-switching.
Kinetic investigation of N2 flowing DC discharges
Authors: Levaton Jacques , Klein Aloisio Nelmo , Amorim Jayr
Published: June 2020

Nitrogen flowing DC discharges were generated between two side-armed electrodes in a drift tube. The discharges operated at gas residence times (t) of ∼4 × 10−4 s, reduced electric fields (E/N) between 90 and 118 Td, and electron densities (ne) between 1010 and 1011 cm−3. A kinetic numerical model was elaborated to study the discharge kinetics. The model calculates the densities of 18 electronic states of nitrogen in the discharge, including the 45 vibrational levels of the N2(X1Σ+g) molecules, as functions of the gas residence time. The model is employed to describe the density profiles of neutral and excited atomic and molecular species, and nitrogen ions, along with the N2(X1Σ+g) vibrational distributions for our experimental conditions. The N2(X1Σ+g) vibrational and gas temperatures, E/N, ne, and the N2(B3Πg), N2(C3Πu), and N2+(B2Σ+u) relative densities were measured in the discharge by optical emission spectroscopy and double probes. The experimental determined gas temperature (Tg), electron density, and reduced electric field were used in the calculations of the electron energy distribution function and reaction rate constants. The vibrational temperature (Tv) and excited species densities measured were compared to the calculated values from the model. Although much attention has been devoted to the study of nitrogen DC discharges in the last few years, this work presents for the first time the N+ – N4+ and N2+(B2Σ+u) ion density distribution together with the densities of 13 atomic and molecular nitrogen states as functions of the discharge gas residence time and N2(X1Σ+g) vibrational distributions calculated for experimental conditions of low pressure DC discharges operating at short residence times.
Solvated iron metallogrid complex exhibits reversible photocycle
Authors: Liebendorfer Adam
Published: June 2020

Measurement with transient optical infrared absorption and X-ray emission spectroscopy reveal independent intra-site transitions, pointing toward future use in advanced light-driven reactions.
Interactions with charged surfaces affect antibody behavior
Authors: Bandari Anashe
Published: June 2020

When charged nanocarriers are used to deliver medication, it is important to ensure their interactions with the body’s proteins do not lead to adverse effects.
Experiment and simulation of the characteristics and mechanisms of self-oscillations in parallel-plate glow discharges
Authors: He Shoujie , Zhao Jianxun , Ha Jing , Zhang Xiaoxian , Zhang Xiwang , Bao Huiling , Li Qing
Published: June 2020

This paper presents experimental results of the characteristics appearance and the mechanism of self-oscillation in a parallel-plate glow discharge with argon as the discharge gas at 266 Pa. The cathode and anode are molybdenum plates with a diameter of 3 cm. The distance between the electrodes is 1 cm. Discharge average voltage and current vary between 300 V and 500 μA, respectively. Light emission from the electrode gap is measured by a charge coupled device camera and argon spectra are recorded of emission lines at 650–800 nm. Results show that self-oscillations exist in the negative differential resistance region in the static V–I curve. An obvious negative differential resistance also can be observed in the dynamic of the V–I curve for the self-oscillations. The appearance and disappearance of the self-oscillating phenomenon are companied with an obvious change in all of the discharge current, discharge images, and electron excited temperature. It can be determined that the self-oscillation is a mode transition between low-current stage of Townsend discharge and high-current stage of glow discharge. The frequency range of self-oscillations starts with 0.4 k Hz up to 24 k Hz in dependence of the average discharge current and the external capacitors. When the self-oscillation disappears, the luminescence shows a significant radial contraction, the electron excitation temperature rise obviously. The frequency of oscillations exhibits a substantial linear increase with the average discharge current and decreases with the increase in the external capacitance from 0 pF up to 250 pF. A resistance–capacitance circuit model is used to simulate the self-oscillation discharge in this experimental glow discharge. Results show that the waveforms simulated by this circuit model are well consistent with those obtained experimentally at different average discharge currents and external parallel capacitances. The equivalent plasma resistance decreases with an increase in the average discharge current. The theory of charge and discharge of a capacitor provides good insights into the characteristics and mechanism of self-oscillations in parallel-plate discharges.
Effect of nano-SiO2 hybridization of PDMS substrate on strain mismatch of flexible electronic film
Authors: Chen Cheng , Gu Wanghang , Chen Rui , Zhao Hanwei , Liu Bing , Ji Hongwei
Published: June 2020

We optimize a flexible electronic composite film by hybridizing the polydimethylsiloxane (PDMS) substrate with hydrophobic nano-SiO2 particles. We then detect the mismatch strain from experiments based on the digital-image correlation method and explore the effect of the substrate nano-SiO2 mass fraction on the strain mismatch over a wide temperature range. The strain mismatch coefficient (SMC) is proposed to better evaluate the degree of strain mismatch between the metal interconnect and the hybrid substrate. Experimental results show that pure PDMS results in relatively large temperature-induced SMC values than nano-SiO2 hybridized substrates and hybridization of nano-SiO2 particles significantly decreases the film SMC value. At a constant temperature, e.g., 20 °C, the SMC value is observed to decrease as the mass fraction of nano-SiO2 in the flexible substrate increases, which turns to be the lowest SMC value as the content of nano-SiO2 reaches 8 wt. %. Finally, by testing the degree of interconnect buckling using atomic force microscopy, our experimental results are verified.
The effect of external electric fields on silicon with superconducting gallium nano-precipitates
Authors: Thorgrimsson Brandur , McJunkin Thomas , MacQuarrie E. R. , Coppersmith S. N. , Eriksson M. A.
Published: June 2020

Motivated by potential transformative applications of nanoelectronic circuits that incorporate superconducting elements and by the advantages of integrating these elements in a silicon material platform, we investigate the properties of the superconductivity of silicon ion implanted with gallium. Here, we measure 40 different samples and explore both a variety of preparation methods (yielding both superconducting and non-superconducting samples) and the reproducibility of one of the preparation methods yielding superconducting samples. While we find agreement with the existing literature that superconducting effects are visible in this system, we also find that this superconductivity is not influenced by voltages applied to a top gate. The superconductivity in this material system is not gateable for applied electric fields as large as 8 MV/cm. We also present results of scanning transmission electron microscopy imaging of some of the same samples for which we report electronic characterization. In agreement with the existing literature, we find that the presence of Ga precipitates is essential for the presence of a superconducting transition in these samples. However, we also find evidence for large inhomogeneities in this system, which we discuss in connection with the lack of gateability we report here.
Atomically flat HfO2 layer fabricated by mild oxidation HfS2 with controlled number of layers
Authors: Wang Y. Y. , Huang S. M. , Yu K. , Jiang J. , Liang Y. , Zhong B. , Zhang H. , Kan G. F. , Quan S. F. , Yu J.
Published: June 2020

In this work, homogeneous surface oxidation of hafnium disulfide (HfS2) is achieved by an extremely simple thermal treatment, i.e., mild oxidization in air. Due to the high thermal stability of hafnium dioxide (HfO2), atomically flat HfO2 is formed on top of unoxidized HfS2 and unlimited layer-by-layer oxidation is observed. The thickness of HfO2 can be controlled by oxidation temperature and time. The HfO2 layer fabricated by the oxidation of HfS2 is smooth and atomically flat with roughness comparable to that of pristine HfS2. Growth of a high-quality, uniform, atomically flat oxide film on top of semiconductor is the first step for the fabrication of field effect transistors and metal-insulator-semiconductor devices. Thus, our results will facilitate the future fabrication of HfO2 films with atomic-scale thickness.
Introducing adaptive cold atmospheric plasma: The perspective of adaptive cold plasma cancer treatments based on real-time electrochemical impedance spectroscopy
Authors: Lin Li , Hou Zichao , Yao Xiaoliang , Liu Yi , Sirigiri Jagadishwar R. , Lee Taeyoung , Keidar Michael
Published: June 2020

Following the understanding of the cold atmospheric plasma jet control, the optimization of plasma parameters for biomedical applications has become an important area of research in the field of plasma-based cancer treatment. A real-time feedback signal is usually required by a control algorithm, such as a self-adaptive plasma jet, which is designed to automatically self-optimize its parameters to adapt to a variety of biomedical applications and situations. In this paper, we introduce the potential of replacing the cell viability or cell stress assay with electrochemical impedance spectroscopy (EIS) to provide a real-time feedback signal for a model predictive control (MPC) method aided by machine learning. The EIS frequency is in the kHz to GHz regime. Therefore, the MPC method is not only designed for minimizing the cancer cell viability, but also considered to optimize cell membrane behaviors and other chemical species dialing. Since these signals are in the range of GHz, we introduce alternatives for the impedance analyzer to measure the impedance spectrum, including a Fabry–Pérot resonator and one of its scanning-array variations.
Oxide 2D electron gases as a reservoir of defects for resistive switching
Authors: Miron Dror , Cohen-Azarzar Dana , Hoffer Barak , Baskin Maria , Kvatinsky Shahar , Yalon Eilam , Kornblum Lior
Published: June 2020

A non-volatile resistive switching device is demonstrated, utilizing a 2D electron gas (2DEG) between a SrTiO3 substrate and an amorphous Al2O3 layer. A large resistance window is observed, and its origin is discussed. We pinpoint the role of the oxide interface in enabling the resistive switching behavior. The switching mechanism is proposed to be of filamentary type that is formed inside the Al2O3 layer, the result of oxygen vacancies that are driven from the interface into the insulating Al2O3 under high electric fields. These results highlight the concept of memristive devices where the 2DEG serves both as the back electrode and as the source of defects necessary for resistive switching, providing a simple and scalable process for future devices.
Accurate measurement of in-plane thermal conductivity of layered materials without metal film transducer using frequency domain thermoreflectance
Authors: Qian Xin , Ding Zhiwei , Shin Jungwoo , Schmidt Aaron J. , Chen Gang
Published: June 2020

Measuring anisotropic thermal conductivity has always been a challenging task in thermal metrology. Although recent developments of pump–probe thermoreflectance techniques such as variable spot sizes, offset pump–probe beams, and elliptical beams have enabled the measurement of anisotropic thermal conductivity, a metal film transducer enabled for the absorption of the modulated pump laser beam and the detection of the thermoreflectance signal. However, the existence of the transducer would cause in-plane heat spreading, suppressing the measurement sensitivity to the in-plane thermal conductivity. In addition, the transducer film also adds complexity to data processing, since it requires careful calibration or fitting to determine extra parameters such as the film thickness and conductivity, and interface conductance between the transducer and the sample. In this work, we discussed the methodology for measuring in-plane thermal conductivity of layered semiconductors and semimetals without any transducer layer. We show that the removal of transducer results in the dominantly large sensitivity to in-plane thermal conductivity compared with other parameters, such as cross-plane thermal conductivity and the absorption depth of the laser beams. Transducerless frequency-domain thermoreflectance (FDTR) measurements are performed on three reference layered-materials, highly ordered pyrolytic graphite, molybdenum disulfide (MoS2), and bismuth selenide (Bi2Se3) and demonstrated using the analytical thermal model that the measured in-plane thermal conductivity showed much-improved accuracy compared with conventional FDTR measurement with a transducer.
Impact of fluorine doping on solution-processed In–Ga–Zn–O thin-film transistors using an efficient aqueous route
Authors: Miyakawa Masashi , Nakata Mitsuru , Tsuji Hiroshi , Iino Hiroaki , Fujisaki Yoshihide
Published: June 2020

Simple and facile solution-processed thin-film transistors (TFTs) using metal-oxide semiconductors are promising for producing large-area electronics. To achieve a high-performance solution-processed metal-oxide TFT at a low processing temperature, simple fluorine doping was performed for obtaining a solution-processed metal-oxide semiconductor through efficient metal aqua complexation. The TFTs fabricated using conventional IGZO and fluorine-doped IGZO (IGZO:F) precursors were evaluated. The IGZO:F fabricated TFT demonstrated higher mobility, better switching characteristics, and enhanced overall TFT performance. This simple, low-temperature fluorine doping technique improved the solution-processed TFT for future scalable and low-cost TFTs.
How woodpecker protects its brain from concussion during pecking compared with chicken and pigeon
Authors: Li Yang , Zhang Wei , Meng Qing Ling , Jiang Gang , Wu Cheng Wei
Published: June 2020

Head injury has become a threat to human life in transportation accidents, construction. and sports. However, woodpeckers can avoid injuring their brain during high velocity and frequency pecking. To reveal the underlying secret, the pecking process of woodpeckers is simulated and compared with that of chickens and pigeons to study the stress wave propagation in their head. The pecking data of live chickens and pigeons are simultaneously obtained from the force sensor and the high-speed video system. The morphological information of the three birds’ heads is also investigated using Micro Computed Tomography (Micro-CT) scanning. The results show that the woodpecker has the highest skull volume fraction and beak length fraction, which could potentially increase its head structural strength and provide more space to dissipate impact stress. The finite element head models of the woodpecker, chicken, and pigeon are established based on the micro-CT images and performed pecking process simulations. The simulated results suggest that the stress wave propagates through both the upper-beak and lower-beak of the woodpecker to ensure the enough structural strength in order to overcome the fierce impact. On the other hand, the structural strength requirement of the chicken and pigeon is not as high as the woodpecker due to their lower pecking intensity. Setting the stouter lower-beak of the chicken and the pigeon as the primary wave propagation path not only ensures their head safety but also avoids direct impact to their brain. The biomechanical design of the bird’s heads, setting a special propagation path for the stress wave, may inspire new approaches to improve and design impact resistance equipment.
Comparison of underwater electrical wire explosions with large and small capacitors charged to a same energy
Authors: Li Liuxia , Qian Dun , Liu Zhigang , Zou Xiaobing , Wang Xinxin
Published: June 2020

In order to investigate the effect of the current rise rate on the underwater electrical wire explosion (UEWE), two pulsed sources were used. One pulsed power source used an energy-storage capacitor of 1 μF while the other used a 200 μF capacitor. These two capacitors were charged to the same energy. The ratio of the current rise rate was about 11 for the UEWEs using these two pulsed sources at the same stored energy. In addition to the rise rate of the current, the wire resistance played an important role in affecting the energy deposition when it was comparable or even lower than the circuit resistance. The experimental results indicated that different capacitors may also lead to different discharge modes, even under the same energy storage and using the same size copper wire. It was found that the deposition energy, deposition power, the deposition ratio, and the discharge mode may influence the shock wave.
Optical fiber interferometer application for high electron density measurements on compact torus plasmas
Authors: Zhang Sen , Chen Chen , Lan Tao , Ding Weixing , Zhuang Ge , Mao Wenzhe , Lan Shijie , Wu Jie , Xu Hangqi , Deng Tijian , Zhu Junfeng , Wu Jiaren , Zu Yiming , Kong Defeng , Zhang Shoubiao , Yao Yuan , Wei Zian , Liu Zixi , Zhou Haiyang , Wang Hai , Wen Xiaohui , Liu Ahdi , Xie Jinlin , Li Hong , Xiao Chijin , Liu Wandong
Published: June 2020

An optical fiber Mach–Zehnder interferometer at a wavelength of 1.55 µm has been developed for measurements of high electron density on compact torus (CT) plasmas with a high time resolution of 0.1 µs and high phase resolution of 6.4 × 10−4 rad. To improve density measurement accuracy, the phase noise of the interferometer has been investigated in detail and optimized. In the bench test, the interferometer was calibrated using a piezoelectric ceramic actuator with known stroke. Initial results on CT plasma show that the optical fiber interferometer provides reliable density measurements at two spatial locations and the bulk velocity of plasma can be determined by the method of time of flight.
Experiment research of post-arc current and cathode spots distribution in medium-high frequency vacuum arc
Authors: Liu Liming , Yuan Zhao , Liu Shan , Chen Lixue , He Junjia , Pan Yuan
Published: June 2020

In this paper, the breaking process of the vacuum circuit breakers is briefly described, and the main factors that influence the post-arc process are analyzed. Based on the detachable vacuum interrupter, the experimental platform of AC breaking is built, and the experiments of the post-arc current measurement and cathode spot observation are completed. The voltage and current during the period of current zero are measured, and the images of cathode spots during the arcing process are obtained. The experimental results show that at the same frequency, the post-arc current Ipac and the post-arc charge Qpac increase with the increase in didtcz(didt at current zero). Under the same conditions of didtcz, Ipac and Qpac decrease with the increase in frequency, but both are unchanged with frequency when the frequency is high enough. With the increase in current frequency, the distribution diameter of cathode spots decreases under the condition of the same didtcz value. According to the characteristics of cathode spot distribution, the metal vapor density under different conditions is calculated. Comparing the calculation results of metal vapor with the experimental results of post-arc current, the concept of metal vapor ionization is put forward. An ionization process of metal vapor after the current zero crossing occurs. The ionization of metal vapor will cause an increase in the number of electrons after the current zero crossing, which affects Ipac, Qpac, and sheath growth.
High filling rate digital PCR through-hole array chip with double independent S-shaped flow channels
Authors: Gao Xu , Li Jinze , Li Chuanyu , Zhang Zhiqi , Zhang Wei , Yao Jia , Guan Ming , Guo Zhen , Li Chao , Zhou Lianqun
Published: June 2020

Sample digital technology is a powerful method for absolute quantification of target molecules such as nucleic acids and proteins. The excellent sample stability and mass production capability has enabled the development of microwell array-based sample digitizing methods. However, in current microwell array chips, samples are loaded by the liquid scraping method, which requires complex manual operation and results in a low filling rate and limited hole filling uniformity. Here, we perform sample loading of a through-hole array chip by a microfluidics-driven method and design a double independent S-shaped flow channels sandwiched through-hole array chip. Because of the capillary force and capillary burst pressure, the sample flowing in the channel can be trapped into through-holes, but cannot flow through the other side. Via air flow and displacement of the remaining sample in the channel, the sample can be partitioned consistently, with zero surplus sample residue in the channel. We evaluated the actual performance of the sample-loading process: the chip enables 99.10% filling rate of 18 500 through-holes, with a grayscale coefficient of variation value of 6.03% determined from fluorescence images. In performing digital polymerase chain reaction on chip, the chip demonstrates good performance for the absolute quantification of target DNA. The simple and robust design of our chip, with excellent filling rate and microsample uniformity, indicates potential for use in a variety of sample digitization applications.
Effect of additives on the growth of HKUST-1 crystals synthesized by microfluidic chips with concentration gradient
Authors: Wu Qirui , Wang Xiaohong , Liu Jinfeng , Wu Jinbo , Zhang Yuan , Zhao Lijuan , Wen Weijia , Gong Xiuqing
Published: June 2020

Metal-organic frameworks (MOFs) have attracted considerable attention as novel nanoporous materials that combine the properties of organic and inorganic porous materials. HKUST-1 is one of the most well-developed and representative MOFs with wide applications in gas storage and separation, adsorption, and capture. In this study, we used microfluidics, an advanced technique of manipulation of small fluid volumes in microscale or even nanoscale channels, to investigate the effect of sodium dodecyl sulfate (SDS) on the growth of HKUST-1 crystals. We directly observed the morphological evolution of HKUST-1 crystals through droplet arrays with the SDS concentration gradient. The morphology of HKUST-1 evolved from cubic to cuboctahedron and finally to octahedron with increasing SDS concentration. The study results demonstrated the important role played by anions in solution in the structural regulation of HKUST-1.
Suppression of nano-hydride growth on Nb(100) due to nitrogen doping
Authors: Veit R. Darren , Farber Rachael G. , Sitaraman Nathan S. , Arias Tomas A. , Sibener S. J.
Published: June 2020

Niobium superconducting radio frequency (SRF) cavities enable the operation of modern superconducting accelerator facilities. These cavities do not approach the theoretical performance limits of Nb due to the deleterious effects of surface defects and chemical inhomogeneities such as Nb hydrides. Nitrogen doping is known to consistently increase the cavity performance and inhibit Nb hydride growth, but a comprehensive understanding of Nb hydride growth and suppression is not yet realized. Scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS), and density functional theory (DFT) calculations presented herein elucidate the real-time, nanoscale structural and electronic evolution of undoped, hydrogen doped, and hydrogen and nitrogen doped Nb(100) due to the growth and suppression of Nb nano-hydrides. DFT calculations in agreement with the experimental data found unique near-surface phases stabilized upon dopant incorporation. The experimental STM and STS results and DFT calculations reported herein provide the first in situ and real-time nanoscale visualization and characterization of the effects of nitrogen doping on Nb hydride suppression and growth. Such information allows for further optimization of nitrogen doping procedures and advances in the performance of SRF materials for next-generation SRF-based accelerators and free electron lasers.
Bioinspired snapping-claw apparatus to study hydrodynamic cavitation effects on the corrosion of metallic samples
Authors: Godínez F. A. , Mayén-Mondragón R. , Guzmán J. E. V. , Chávez O. , Gavaises M. , Montoya R.
Published: June 2020

A creative low-cost and compact mechanical device that mimics the rapid closure of the pistol shrimp claw was used to conduct electrochemical experiments, in order to study the effects of hydrodynamic cavitation on the corrosion of aluminum and steel samples. Current–time curves show significant changes associated with local variations in dissolved O2 concentration, cavitation-induced erosion, and changes in the nature of the surface corrosion products.
Injection-seeded backward terahertz-wave parametric oscillator
Authors: Takida Yuma , Nawata Kouji , Minamide Hiroaki
Published: June 2020

Engineered quasi-phase-matching in a periodically poled nonlinear crystal has enabled backward optical parametric oscillators, where a pump photon is down-converted to counterpropagating signal and idler photons without an optical cavity. Here, we demonstrate an injection-seeded backward terahertz-wave parametric oscillator (BW-TPO) based on a slant-strip-type periodically poled lithium niobate crystal. A continuous-wave single-frequency laser is used in the BW-TPO pumped by sub-nanosecond 1064.4-nm pulses to provide an injection seed beam for the forward-propagating idler wavelength at 1065.7 nm, resulting in over a 1000-fold enhancement in backward-propagating 0.335-THz output energy, a 63% reduction of the oscillation threshold, and a quantum conversion efficiency as high as 47%. Thanks to the unique advantage of cavity-less oscillation, these improvements and stable operation in the BW-TPO are achieved without any stabilization control of either seed or oscillation modes. Our results show that such an injection-seeded BW-TPO is promising as a compact, efficient, and robust THz-wave source for a wide variety of applications.
Self-reduction derived nickel nanoparticles in CdS/Ni(OH)2 heterostructure for enhanced photocatalytic hydrogen evolution
Authors: Wang Xiaoning , Zhang Xiaofei , Gao Wenqiang , Sang Yuanhua , Wang Yanmin , Liu Hong
Published: June 2020

Nickel-based materials have been used in electrochemical water splitting and as a co-catalyst to effectively improve photocatalytic activity. However, the mechanism of the catalytic effect on hydrogen evolution of NiO and Ni(OH)2 needs further investigation because of the high risk in self-reduction with photo-induced electrons. In this work, the self-reduction of Ni2+ was confirmed during the photocatalytic H2 evolution in the CdS/Ni(OH)2 hybrid materials. Meanwhile, in situ formed metallic Ni plays an important role in the increase in the catalytic activity. Fortunately, only a few photo-induced electrons participate in the reduction of Ni2+ in CdS/Ni(OH)2 hybrid materials. The existence of metallic Ni would prevent more Ni2+ from self-reduction. The synergistic effect of Ni(OH)2 and metallic Ni contributes to the improvement of H2 evolution of CdS nanorods.