bluuebunny/crossref_metadata_2025 huggingface dataset:
Flux Transfer Event Showers at Mercury: Dependence on Plasma β and Magnetic Shear and Their Contribution to the Dungey Cycle
Authors: Sun W. J. , Slavin J. A. , Smith A. W. , Dewey R. M. , Poh G. K. , Jia X. , Raines J. M. , Livi S. , Saito Y. , Gershman D. J. , DiBraccio G. A. , Imber S. M. , Guo J. P. , Fu S. Y. , Zong Q. G. , Zhao J. T.
Published: October 2020

Mercury's flux transfer event (FTE) showers are dayside magnetopause crossings accompanied by large numbers (≥10) of magnetic flux ropes (FRs). These shower events are common, occurring during 52% (1,953/3,748) of the analyzed crossings. Shower events are observed with magnetic shear angles (θ) from 0° to 180° across the magnetopause and magnetosheath plasma β from 0.1 to 10 but are most prevalent for high θ and low plasma β. Individual FR duration correlates positively, while spacing correlates negatively, with θ and plasma β. FR flux content and core magnetic field intensity correlate negatively with plasma β, but they do not correlate with θ. During shower intervals, FRs carry 60% to 85% of the magnetic flux required to supply Mercury's Dungey cycle. The FTE showers and the large amount of magnetic flux carried by the FTE‐type FRs appear quite different from observations at Earth and other planetary magnetospheres visited thus far.
Electrical Conductivity of Aqueous Magnesium Sulfate at High Pressure and Low Temperature With Application to Ganymede's Subsurface Ocean
Authors: Pan Yilong , Yong Wenjun , Secco Richard A.
Published: October 2020

Ganymede has strong evidence of a subsurface ocean primarily composed of MgSO4. We conducted experimental measurements of the electrical conductivity of aqueous MgSO4 at 200–1,200 MPa and 243–295 K in a multianvil press, simulating the high‐pressure and low‐temperature (HPLT) conditions of Ganymede's subsurface ocean. A numerical model is proposed with logσ =  − 3.1605+940.931/T+0.8986logc+2logΛ0 − log(5Λ0+2695c1/2), where σ is electrical conductivity in S/m, T is temperature in K, c is molar concentration in mol/L, and Λ0 is limiting equivalent conductance in S·cm2·equiv−1. We used this model to generate electrical conductivity curves up to 500 km deep in Ganymede and found that the values are lower than previously predicted. Our novel experimental methods demonstrate access to the HPLT environment of liquid samples that expands our ability for experimental simulation of icy ocean worlds in the outer solar system.
Barrier for the Eastward Propagation of Madden‐Julian Oscillation Over the Maritime Continent: A Possible New Mechanism
Authors: Zhang Lei , Han Weiqing
Published: October 2020

The Madden‐Julian Oscillation (MJO) is the dominant intraseasonal variability of the tropical troposphere. Many MJOs originate from the tropical Indian Ocean and propagate into the Pacific via the Maritime Continent (MC). However, 30–50% of the MJO stalls over the MC, while its cause remains unclear. Here, we find that a new interbasin coupled phenomenon dubbed “Warm Pool Dipole” (WPD), which is associated with out‐of‐phase sea surface temperature anomalies (SSTAs) in the southeast Indian Ocean and the western central tropical Pacific, may play an important role in controlling the MJO propagation. During the positive WPD, ~67% of the MJO is stalled over the MC, whereas none is stalled during its negative phase. It is the SSTAs at both poles of the WPD together that produce these effects. The results are robust to cross–data set differences and supported by model experiments, although the small observational sample size limits their level of statistical significance.
Statistical Evidence for EMIC Wave Excitation Driven by Substorm Injection and Enhanced Solar Wind Pressure in the Earth's Magnetosphere: Two Different EMIC Wave Sources
Authors: Chen Huayue , Gao Xinliang , Lu Quanming , Tsurutani Bruce T. , Wang Shui
Published: October 2020

Substorm injection and solar wind dynamic pressure have long been considered as two main drivers of electromagnetic ion cyclotron (EMIC) wave excitation, but clear observational evidence is still lacking. With Van Allen Probes data from 2012–2017, we have investigated the roles of the two EMIC wave drivers separately, by using time‐modified AE+ and
. Both the occurrence rate and magnetic amplitude of waves significantly increase with the enhancement of each index. During large AE+, EMIC waves are mainly generated in the dusk sector (16 ≤ MLT ≤ 20) and near the magnetic equator (|MLAT| < 10°). This is presumably due to substorm‐injected protons drifting from midnight sector to the plasmaspheric bulge. While during large
, EMIC waves mainly occur in the noon sector (9 ≤ MLT ≤ 15). But there exist higher‐latitude (10° < |MLAT| < 20°) source regions besides equatorial source, possibly due to the minimum B regions. Our results provide strong observational support to existing generation mechanisms of EMIC waves in the Earth's magnetosphere.
Seasonal Forecasts of the Exceptional Northern Hemisphere Winter of 2020
Authors: Lee Simon H. , Lawrence Zachary D. , Butler Amy H. , Karpechko Alexey Y.
Published: October 2020

The winter of 2019–2020 was dominated by an extremely strong stratospheric polar vortex and positive tropospheric Arctic Oscillation (AO). Here, we analyze forecasts from six different prediction systems contributing to the C3S seasonal forecast database. Most performed very strongly, with consistently high skill for January–March 2020 from forecasts launched through October–December 2019. Although the magnitude of the anomalies was underestimated, the performance of most prediction systems was extremely high for a positive AO winter relative to the common hindcast climate. Ensemble members which better predicted the extremely strong stratospheric vortex better predicted the extreme tropospheric state. We find a significant relationship between forecasts of the anomalous midlatitude tropospheric wave pattern in early winter, which destructively interfered with the climatological stationary waves and the strength of the stratospheric vortex later in the winter. Our results demonstrate a strong interdependence between the accuracy of stratospheric vortex and AO forecasts.
Observations of the Size Distribution of Frazil Ice in an Ice Shelf Water Plume
Authors: Frazer Eamon K. , Langhorne Pat J. , Leonard Greg H. , Robinson Natalie J. , Schumayer Dániel
Published: October 2020

The size distribution of frazil ice is currently unconstrained in ice shelf cavity modeling. Here we observe the time‐dependent behavior of the number and size of frazil ice particles in an Ice Shelf Water plume. A novel acoustic scattering inversion was used to infer frazil ice crystal diameters, assuming a log‐normal distribution. Observation sites were on land‐fast sea ice approximately 13 and 33 km from the front of the McMurdo Ice Shelf, Antarctica. The water column from the ice‐water interface to 30 m below mean sea level was monitored over 3 weeks in November of 2016 and 2017. At 15 m below sea level the mean frazil crystal diameter was ∼1 mm. Fractional ice volume, derived from frazil crystal size and number density, correlates with in situ supercooling (up to 50 mK at 15 m below sea level). The data presented here provide valuable input for model initiation and evaluation.
Excitation of Oxygen Ion Cyclotron Harmonic Waves in the Inner Magnetosphere: Hybrid Simulations
Authors: Liu Kaijun , Min Kyungguk , Feng Bolu , Wang Yan
Published: October 2020

Hybrid simulations are carried out to investigate the excitation of oxygen ion cyclotron harmonic waves observed in the inner magnetosphere. The simulations show that these waves can be excited by energetic oxygen ions of a ring‐like velocity distribution. The excited waves have properties consistent with observations, but their nearly perpendicular propagation disagrees with the quasi‐parallel propagation from the singular value decomposition (SVD) analysis reported earlier. By performing the same SVD analysis on the simulated waves in a three‐dimensional simulation, it is demonstrated that the superposition of multiple waves with different azimuthal angles can cause the commonly used SVD analysis of wave propagation to yield incorrectly small wave normal angles. In addition, the results show that the enhanced waves scatter oxygen ions mainly along v⊥ through cyclotron resonance. The waves may also scatter energetic radiation belt electrons through bounce resonance and transit time scattering, similar to fast magnetosonic waves.
How Does the Melting Impact Charge Separation in Squall Line? A Bin Microphysics Simulation Study
Authors: Xu Liangtao , Xue Lulin , Geresdi Istvan
Published: October 2020

A new electrification and discharge model was developed based on a two‐moment bin microphysical scheme coupled with the Weather Research and Forecasting (WRF) model. Based on the electrical model, the role of the noninductive charging mechanism associated with the melting processes of both snow and graupel (rimed particles) in the charge structure formation in the stratiform region of an organized convective system was examined. Our results showed that the snow melting charging mechanism forms a substantial positive charge layer near and below 0°C isotherm in the stratiform region of a squall line. It was also found that the graupel melting charging process mostly enhanced the positive charge layer in the convective region with little impact in the stratiform region. The in situ charging of noninductive collisional and melting processes and the charge transportation from the convective core all contribute to the charge structure formation in the stratiform region of a squall line.
Single-cell individualized electroporation with real-time impedance monitoring using a microelectrode array chip
Authors: Zhang Zhizhong , Zheng Tianyang , Zhu Rong
Published: October 2020

The ability to precisely deliver molecules into single cells while maintaining good cell viability is of great importance to applications in therapeutics, diagnostics, and drug delivery as it is an advancement toward the promise of personalized medicine. This paper reports a single-cell individualized electroporation method with real-time impedance monitoring to improve cell perforation efficiency and cell viability using a microelectrode array chip. The microchip contains a plurality of sextupole-electrode units patterned in an array, which are used to perform in situ electroporation and real-time impedance monitoring on single cells. The dynamic recovery processes of single cells under electroporation are tracked in real time via impedance measurement, which provide detailed transient cell states and facilitate understanding the whole recovery process at the level of single cells. We define single-cell impedance indicators to characterize cell perforation efficiency and cell viability, which are used to optimize electroporation. By applying the proposed electroporation method to different cell lines, including human cancer cell lines and normal human cell lines individually, optimum stimuli are determined for these cells, by which high transfection levels of enhanced green fluorescent protein (EGFP) plasmid into cells are achieved. The results validate the effectiveness of the proposed single-cell individualized electroporation/transfection method and demonstrate promising potential in applications of cell reprogramming, induced pluripotent stem cells, adoptive cell therapy, and intracellular drug delivery technology.
Inkjet printing-based fabrication of microscale 3D ice structures
Authors: Zheng Fengyi , Wang Zhongyan , Huang Jiasheng , Li Zhihong
Published: October 2020

This study proposed a method for fabricating 3D microstructures of ice without a supporting material. The inkjet printing process was performed in a low humidity environment to precisely control the growth direction of the ice crystals. In the printing process, water droplets (volume = hundreds of picoliters) were deposited onto the previously formed ice structure, after which they immediately froze. Different 3D structures (maximum height = 2000 µm) could be formed by controlling the substrate temperature, ejection frequency and droplet size. The growth direction was dependent on the landing point of the droplet on the previously formed ice structure; thus, 3D structures could be created with high degrees of freedom.
The effects of inhibition of fatty acid amide hydrolase (FAAH) by JNJ-42165279 in social anxiety disorder: a double-blind, randomized, placebo-controlled proof-of-concept study
Authors: Schmidt Mark E. , Liebowitz Michael R. , Stein Murray B. , Grunfeld Jennifer , Van Hove Ilse , Simmons W. Kyle , Van Der Ark Peter , Palmer James A. , Saad Ziad S. , Pemberton Darrel J. , Van Nueten Luc , Drevets Wayne C.
Published: October 2020

JNJ-42165279 is a selective inhibitor of fatty acid amide hydrolase (FAAH), the enzyme responsible for the degradation of fatty acid amides (FAA) including anandamide (AEA), palmitoylethanolamide (PEA), and N-oleoylethanolamide (OEA). We assessed the efficacy, safety, tolerability, pharmacokinetics, and pharmacodynamics of treatment with JNJ-42165279 in subjects with social anxiety disorder (SAD). This was a multicenter, double-blind, placebo-controlled study randomizing subjects to 12 weeks of treatment with either JNJ-42165279 (25 mg daily) or placebo (PBO). The primary endpoint was the change in the Liebowitz Social Anxiety Scale (LSAS) total score from baseline to end of study. Secondary endpoints included the Hamilton Anxiety Scale (HAM-A), Hamilton Depression Rating Scale (HDRS17), and the Clinical Global Impression-Improvement (CGI-I). Samples were collected for plasma concentration of AEA, PEA, OEA, and JNJ-42165279. A total of 149 subjects were enrolled with a mean baseline LSAS total score of 102.6 (SD 16.84). The mean change from baseline (SD) in LSAS total score at week 12 was numerically greater for JNJ-42165279: −29.4 (27.47) compared to PBO: −22.4 (23.57) but not significant. The percentage of subjects with ≥30% improvement from baseline in the LSAS total score was significantly higher for JNJ-42165279 (42.4%) compared to PBO (23.6%) (p value = 0.04). The percentage of subjects with a CGI-I score of much or very much improved was also significantly higher for JNJ-42165279 (44.1%) than for PBO (23.6%) (p value = 0.02). The drug was well tolerated. JNJ-42165279 appears to elicit an anxiolytic effect in subjects with SAD although trough concentrations with 25 mg once daily appeared to be insufficient to completely inhibit FAAH activity which may have led to suboptimal efficacy. ClinicalTrials.gov Identifier: NCT02432703.
Notch3 contributes to T-cell leukemia growth via regulation of the unfolded protein response
Authors: Giuli Maria Valeria , Diluvio Giulia , Giuliani Eugenia , Franciosa Giulia , Di Magno Laura , Pignataro Maria Gemma , Tottone Luca , Nicoletti Carmine , Besharat Zein Mersini , Peruzzi Giovanna , Pelullo Maria , Palermo Rocco , Canettieri Gianluca , Talora Claudio , d’Amati Giulia , Bellavia Diana , Screpanti Isabella , Checquolo Saula
Published: October 2020

Unfolded protein response (UPR) is a conserved adaptive response that tries to restore protein homeostasis after endoplasmic reticulum (ER) stress. Recent studies highlighted the role of UPR in acute leukemias and UPR targeting has been suggested as a therapeutic approach. Aberrant Notch signaling is a common feature of T-cell acute lymphoblastic leukemia (T-ALL), as downregulation of Notch activity negatively affects T-ALL cell survival, leading to the employment of Notch inhibitors in T-ALL therapy. Here we demonstrate that Notch3 is able to sustain UPR in T-ALL cells, as Notch3 silencing favored a Bip-dependent IRE1α inactivation under ER stress conditions, leading to increased apoptosis via upregulation of the ER stress cell death mediator CHOP. By using Juglone, a naturally occurring naphthoquinone acting as an anticancer agent, to decrease Notch3 expression and induce ER stress, we observed an increased ER stress-associated apoptosis. Altogether our results suggest that Notch3 inhibition may prevent leukemia cells from engaging a functional UPR needed to compensate the Juglone-mediated ER proteotoxic stress. Notably, in vivo administration of Juglone to human T-ALL xenotransplant models significantly reduced tumor growth, finally fostering the exploitation of Juglone-dependent Notch3 inhibition to perturb the ER stress/UPR signaling in Notch3-dependent T-ALL subsets.
Differential sensitivity of acute myeloid leukemia cells to daunorubicin depends on P2X7A versus P2X7B receptor expression
Authors: Pegoraro Anna , Orioli Elisa , De Marchi Elena , Salvestrini Valentina , Milani Asia , Di Virgilio Francesco , Curti Antonio , Adinolfi Elena
Published: October 2020

Acute myeloid leukemia (AML) is a common adult leukemia often arising from a preexistent myelodysplastic syndrome (MDS). High mortality rates of AML are caused by relapse and chemoresistance; therefore, we analyzed the role of P2X7 receptor (P2X7R) splice variants A and B in AML progression and response to chemotherapy. The expression of P2X7RA and P2X7RB was investigated in samples obtained from MDS and AML untreated subjects or AML patients in relapse or remission after chemotherapy. Both P2X7RA and P2X7RB were overexpressed in AML versus MDS suggesting a disease-promoting function. However, in relapsing patients, P2X7RA was downmodulated, while P2X7RB was upmodulated. Treatment with daunorubicin (DNR), one of the main chemotherapeutics for AML, upregulated P2X7RB expression while reducing P2X7RA mRNA in AML blasts. Interestingly, DNR administration also caused ATP release from AML blasts suggesting that, following chemotherapy, activation of the receptor isoforms via their agonist will be responsible for the differential survival of blasts overexpressing P2X7RA versus P2X7RB. Indeed, AML blasts expressing high levels of P2X7RA were more prone to cell death if exposed to DNR, while those overexpressing P2X7RB were more vital and even protected against DNR toxicity. These data were reproducible also in HEK-293 cells separately expressing P2X7RA and B. P2X7RA facilitation of DNR toxicity was in part due to increased uptake of the drug inside the cell that was lost upon P2X7RB expression. Finally, in an AML xenograft model administration of DNR or the P2X7R antagonist, AZ10606120 significantly reduced leukemic growth and coadministration of the drugs proved more efficacious than single treatment as it reduced both P2X7RA and P2X7RB levels and downmodulated c-myc oncogene. Taken together, our data suggest P2X7RA and P2X7RB as potential prognostic markers for AML and P2X7RB as a therapeutic target to overcome chemoresistance in AML relapsing patients.
Quasi-solid-state dye-sensitized indoor photovoltaics with efficiencies exceeding 25%
Authors: Liu I.-Ping , Cho Yu-Syuan , Teng Hsisheng , Lee Yuh-Lang
Published: October 2020

Quasi-solid-state dye-sensitized indoor photovoltaics fabricated using polymer blend electrolytes, judicious cosensitization and polymeric catalysts show efficiencies beyond 25% under 1000-lux artificial lighting.
Coronavirus and Homo Sapiens
Authors: Natarajan Pooja , Kanchi Muralidhar , Gunaseelan Vikneswaran , Sigamani Alben , Harmon James , Belani Kumar
Published: October 2020

The Spanish influenza pandemic of 1918 globally claimed death between 50 and 100 million lives. In India, it was referred to as “The Bombay Fever,” and accounted for a fifth of the global death toll at that time. The current outbreak of the novel coronavirus disease 2019 (COVID-19), a new human-infecting beta coronavirus, has demonstrated that the size of an organism does not reflect on its ability to affect almost an entire human population. COVID-19, first detected in December 2019 in Wuhan, China, that spread rapidly worldwide. In humans, this disease ranged from flu-like symptoms to severe acute hypoxic respiratory failure. By appearance, this virus closely related to two bat-derived severe acute respiratory syndrome (SARS) coronaviruses. Although bats were likely the original host, animals sold at the Huanan seafood market in Wuhan might have been the intermediate host that enabled the emergence of the virus in humans. Under the electron microscope, the severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) virus grips its receptor tighter than the virus behind the SARS outbreak in 2003 to 2004. The viral particle docks onto the angiotensin-converting enzyme 2 (ACE2) receptor and initiates viral entry. This review discusses the various aspects of the SARS-CoV-2 virus, its structure, pathophysiology, mechanism of interaction with human cells, virulence factors, and drug involved in the treatment of the disease.
Influence of Body Temperature on Bispectral Index-Guided Anesthetic Management in Off-Pump Coronary Artery Bypass Grafting
Authors: Kanchi Muralidhar , Nair Priya , Manjunath Rudresh , Belani Kumar
Published: October 2020

Background Perioperative hypothermia is not uncommon in surgical patients due to anesthetic-induced inhibition of thermoregulatory mechanisms and exposure of patients to cold environment in the operating rooms. Core temperature reduction up to 35°C is often seen in off-pump coronary artery bypass graft (OP-CABG) surgery. Anesthetic depth can be monitored by using bispectral (BIS) index. The present study was performed to evaluate the influence of mild hypothermia on the anesthetic depth using BIS monitoring and correlation of BIS with end-tidal anesthetic concentration at varying temperatures during OP-CABG.

Materials and Methods In a prospective observational study design in a tertiary care teaching hospital, patients who underwent elective OP-CABG under endotracheal general anesthesia, were included in the study. Standard technique of anesthesia was followed. BIS, nasopharyngeal temperature, and end-tidal anesthetic concentration of inhaled isoflurane was recorded every 10 minutes. The BIS was adjusted to between 45 and 50 during surgery.

Results There were 40 patients who underwent OP-CABG during the study period. The mean age was 51.2 ± 8.7 years, mean body mass index 29.8 ± 2.2, and mean left ventricular ejection fraction was 55.4 ± 4.2%. Anesthetic requirement as guided by BIS between 45 and 50 correlated linearly with core body temperature (r = 0.999; p < 0.001). The mean decrease in the body temperature at the end of 300 minutes was 2.2°C with a mean decrease in end-tidal anesthetic concentration of 0.29%. The reduction in end-tidal anesthetic concentration per degree decrease in temperature was 0.13%. None of the patients reported intraoperative recall.

Conclusion In this study, BIS monitoring was used to guide the delivery concentration of inhaled anesthetic using a targeted range of 45 to 50. BIS monitoring allowed the appropriate reduction of anesthetic dosing requirements in patients undergoing OP-CABG without risk of awareness. There was a significant reduction in anesthetic requirements associated with reduction of core temperature. The routine use of BIS is recommended in OP-CABG to titrate anesthetic requirement during occurrence of hypothermia and facilitate fast-track anesthesia in this patient population.
The local co-evolution of firms and governments in the Information Age
Authors: Lundan Sarianna , Cantwell John
Published: October 2020

The governance structures of the value-creating activities of MNEs have evolved towards more networked forms that are geographically highly concentrated and involve partnering with diverse actors. The experimentation that takes place within these corporate networks has a parallel on the government side, where subnational governments, and particularly cities as hubs of economic activity, have increased their profile and level of cooperative activity. We argue that engagement in these partnerships is an essential way in which firms and governments co-evolve and create the basis for sustainable economic growth in the Information Age. While the origins of this collaborative form of governance reside in the increasing knowledge intensity of value creation, its implications go far beyond MNE value creation and capture, extending to issues of global governance such as climate change and sustainable development goals. We examine the implications of this process of co-evolution both in terms of the costs of developing the requisite corporate capabilities as well as the legitimacy of these efforts as part of a deliberative democracy.
Combined Properties of Al/Ni Reactive Multilayer Films During High-Rate Heating Using a Pulse of Current
Authors: Wang Yao , Guo Fei , Zhou Qin , Jiang Hongchuan , Li Yong , Wang Liang
Published: October 2020

We use pulses of current to investigate the combined properties of Al/Ni multilayer films under high-rate heating by measuring current-voltage waveforms and the flyer velocity. Explosion occurs earlier in the Al/Ni multilayer foil than in the Al and Ni films, suggesting that the addition of Al/Ni affects the electrical exploding process, which is not controlled solely by resistance. The experiments indicates that the differences between the physical properties of the Al and Ni films is a factor to causing higher plasma electron temperature and absorb more electrical energy than the single Al or Ni film. The flyer velocity of the Al/Ni multilayer film is much lower than that of the Al film due to the high adiabatic index of Ni.
Study on Annealing Effect of Fe51.6Co34.4Hf7B6Cu1 Amorphous Alloy
Authors: Zhang Yanhui , Guo Jiaqi
Published: October 2020

Microwave absorbing materials have a wide range of applications in both military and civil areas. Fe-based amorphous alloys have superior soft magnetic properties, which possess high permeability and high saturation magnetization. The studies on Fe-based amorphous materials have a high theoretical and practical value. In this article, the effect of different temperatures treatments on Fe51.6Co34.4Hf7B6Cu1 amorphous alloy prepared by melt-spun technique is investigated. The traces of crystalline phase are precipitated from the treated sample. The volume percentages of crystalline phase are 2.1% and 7.4% in the annealed samples at 200 °C and 300 °C, respectively. The microwave absorption performance of the microcrystalline samples after isothermal heat treatment is better than the other.
Determination of Fe in Graphene by Inductively Coupled Plasma Optical Emission Spectrometer
Authors: Lu Yi , Gong Chen , Wu Lijun , Liu Hongchao , Guo Guojian
Published: October 2020

The Fe in graphene was determined by inductively coupled plasma optical emission spectroscopy. The effects of digestion temperature, digestion system, analyzing spectral line, RF power, peristaltic pump flow rate, and working gas flow rate on the measurement results were investigated respectively. The results show that the best digestion effect appear when the digestion temperature is 550 °C and the digestion system is 3ml hydrochloric acid combined with 1ml nitric acid. The most stable and reliable test results obtained when the analyzing spectral line is 259.941 nm, the RF power is 1400W, the peristaltic pump flow rate is 50r/min, the atomizing gas flow rate is 0.8L/min, and the auxiliary gas flow rate is 1.0L/min. The detection limit of the measurement result is 0.029mg/L, the relative standard deviation (n=6) is between 2.5% and 3.2%, and the recovery is between 96.3% and 108.2%.
Transient Bending Vibration of a Piezoelectric Semiconductor Nanofiber under a Harmonic Shear Force
Authors: Liang Yuxing
Published: October 2020

A harmonic shear end force induced the transient bending vibration is analyzed in a cantilevered n-type ZnO nanofiber. Based on the mechanical movement equation, continuity condition of current density and charge equation of electrostatics, the theoretical analysis is carried out by a one-dimensional model. The evolution of the deflection and perturbation of the electron concentration caused by the harmonic end force are calculated. Numerical results show that the vibration period of the piezoelectric semiconductor fiber is about twice that of the harmonic force, which referenced to design the nanosensors and nanogenerators.
Analysis of Potential and Electron Density Behaviour in Extremely Scaled Si and InGaAs MOSFETs Applying Monte Carlo Simulations
Authors: Islam Aynul , Aynul Anika Tasnim , Kalna Karol
Published: October 2020

Scaling of Silicon and InGaAs MOSFETs of a 25 nm gate length till shortest gate length of 5 nm, simulated this nano-device by Monte Carlo (MC) with quantum corrections. The transistors are scaled-down only in lateral dimensions in order to study electron transport approaching a ballistic limit along the scaled channel following experimental works. These MC simulations are able to give detailed insight into physical behaviour of electron velocity, electron density, and potential in relation to the drive current. We found that electron peak velocity increases during the scaling in Si MOSFETs till the 10 nm gate length and then dramatically declines due to a strong long-range Coulomb interaction among the source and the drain [16]. This effect is not observed in the equivalent InGaAs MOSFETs in which electron peak velocity exhibits double peak which steadily increases during the scaling [16]. However, the increasing of current in the equivalent InGaAs MOSFETs is moderate, by about 24 %, by comparing of current in the Si MOSFETs of 74 % delivered by 5 nm channel transistor.
Novel Responsive Controllable Solidification Plugging Agent to Overcome Lost Circulation Problems in Long Open Hole Intervals
Authors: Li Long , Yin Da , Hao Weiwei
Published: October 2020

A new type of responsive controllable solidification plugging agent (RCSP) for long open hole intervals was developed, and the sealing characteristics were evaluated. RCSP had the characteristics of rapid water loss, high filter-cake consistency and good residence capacity. The experimental results indicated that the maximum pressure-bearing capacities of plugged zones in 5 mm and 10 mm slotted templets are 16.6 MPa and 11 MPa, respectively. So RCSP is an effective plugging agent for strengthening wellbore stability. RCSP is appropriate for sealing wide range of fracture sizes. Using RCSP-based plugging mud to address lost circulation problems in troublesome thief zones is a very powerful and economical approach. In the future, RCSP might hold great promise to resolve lost circulation problems in multiple leakage zones in long open hole sections.
The Corrosion Behaviour of Amorphous Metal Fiber Compared With That of Stainless Steel Fiber
Authors: Wu Zhongwang , Jia Yuwei , Jin Zili , Ren Huiping , Ni Xiaojun
Published: October 2020

Amorphous metal fiber exhibits high corrosion resistance, excellent mechanical properties and is good material for reinforcing concrete matrix. To compare with the corrosion behaviour of amorphous metal fiber and stainless steel fiber, the corrosion resistance was investigated by electrochemical polarization in 0.5 M H2SO4, 0.1 M FeCl3 and 3.5 wt% NaCl solutions, respectively. The results show that amorphous metal fiber exhibits more superior corrosion resistance than that of stainless steel fiber. The amorphous metal fiber has excellent pitting corrosion resistance in 3.5 wt% NaCl solution, and the stainless steel fiber is susceptible to pitting corrosion. The amorphous metal fiber is spontaneously passivated in 0.1 M FeCl3 solutions, and the stainless steel fiber doesn’t form passivation.
Investigation on Impact Induced Damage in Boron Carbide with Simultaneous X-ray Imaging and Diffraction
Authors: Zhou Lijiang , Xu Songlin , Peng Weicai
Published: October 2020

The macro-scale mechanical behaviors of materials under impact can be dominated by the meso and micro-scale deformation mechanisms and cracking patterns. In combination with the X-ray imaging and diffraction techniques, impact tests are performed on boron carbide (B4C) ceramic bulks with two different porosities by a miniature split Hopkinson pressure bar (SHPB). After a transient quasi-elastic deformation process, catastrophic failure occurs in the high-porosity bulk, with a weak failure strength. Abundant tensile and shear cracks nucleate in the low porosity bulk, but cannot connect into a cracks network due to the high adhesive force, and finally the dissociative failure occurs with several main cracks penetrating. By analyzing the diffraction peak splitting phenomenon, the extent of shear deformation is quantitatively characterized to be 60-70% of the compression deformation. The damage extent is expressed by the voids volume induced by cracks. The macroscopic stress increment of B4C bulk under impact can be expressed by a function of the damage extent evolution.
Preparation and Parameters Measurement of Magnetic Fluid
Authors: Hao Ruican , Liu Huagang , Wang Shang
Published: October 2020

Magnetic fluid is a liquid nano-size magnetic material which has unique properties such as flowability, paramagnetism, and magnetic permeability. The composition of magnetic fluid was introduced. The preparation devices were collected and listed. The preparation of magnetic particles was made by chemical coprecipitation. The particles were coated with surfactant in the experiment. Then the coated particles were added in the base carrier fluid according to the procedure of preparation. Magnetic fluid was prepared by chemical coprecipitation. The parameters of magnetic fluid were measured for kinds of engineering applications. The magnetism of magnetic fluid is one of the most important parameters, which was measured and displayed. The saturated magnetism should be increased for more applications.
Effects of Temperature and Strain Rate on Mechanical Behaviour of Laser Rapid Forming Ti-6Al-4V Alloy
Authors: Xiang Wenli , Shu Xinzhu , Sun Kun
Published: October 2020

Using the electronic universal test machine, the high temperature split Hopkinson bar and the gleeble-1500 thermal simulator, the room temperature quasi-static compression experiment, room temperature dynamic compression experiment, high temperature dynamic compression experiment and the high temperature quasi-static compression experiment on corresponding cylindrical samples of Laser Rapid Forming Ti-6Al-4V(LRF TC4) titanium alloy have been conducted, respectively. And effects of the temperature and strain rate on mechanical behavior of LRF TC4 alloy have been investigated. It is showed that, whether quasi-static compression or high strain rate compression, the strength of LRF TC4 decreases and the plasticity increases at the high temperature. Under the high temperature quasi-static compression, LRF TC4 still has the strain strengthening effects at 400°C, the flow stress changes steadily in the stage of the plastic deformation at 500°C and the strength of LRF TC4 dropped drastically when the temperature goes beyond 500°C. Under the high temperature and high strain rate, the flow stress changes steadily in the plastic deformation stage due to dual function of both strain rate strengthening and temperature softening and adiabatic temperature rise within the sample reduced with the increase of the deforming temperature. Under the coupling function of high temperature and high strain rate, the effect of strain-rate strengthening is weaker than the effect of temperature softening.
Effect of Microstructure on the Johnson-Cook Constitutive Model Parameters of Ti-6Al-4V Alloy
Authors: Ren Yu , Ma Yuantong , Pan Qiyun
Published: October 2020

Constitutive models are widely used to predict the mechanical behavior of materials. In this research, the Johnson-Cook (J-C) constitutive model parameters of Ti-6Al-4V (Ti64) alloy with different microstructural details were fitted based on the mechanical properties over a broad range of strain rates and temperatures. The results indicate that the microstructural details have a significant effect on the mechanical properties and the J-C model parameters of Ti64. The five material parameters (A, B, n, C, m) in J-C model of Ti64 exhibit completely different varying trends as a function of the equiaxed primary α-phase volume fraction and α-platelet thickness. These changes in J-C model parameters of Ti64 can be attributed to the effect of microstructural details on the dislocation nucleation and motion under different deformation conditions.
The Application of Grouting Sealing Material in the Treatment of Pavement Reflective Cracking
Authors: Liang Hao , Song Xiaojin , Jiang Feng , Wei Hui
Published: October 2020

Grouting sealing technique was applied for the treatment of pavement reflective cracking in HengDe expressway and the treatment effect which evaluated by the portable falling weight deflectometer was demonstrated in this paper. Analysis considers that grouting sealing technique could effectively improve the bearing capacity of the pavement where distress happened by reducing the deflections of the pavement up to 5%-25%.
Reliable Resistive Switching Behaviour of Ag/Ta2O5/Al2O3/p++-Si Memory Device
Authors: Tian Wei , Ilyas Nasir , Li Dongyang , Li Chunmei , Jiang Xiangdong , Li Wei
Published: October 2020

In this article, we demonstrate a resistive switching memory device based on a very simple bilayer structure of Ag/Ta2O5/Al2O3/p++-Si. As compared to a single-layer based device of Ag/Ta2O5/p++-Si, a uniform bistable resistive switching behaviour with on/off ratio over 104 demonstrates that the Ag/Ta2O5/Al2O3/p++-Si device could be a promising candidate for the memory device, in which the total resistance could also be adjusted by modifying the applied electric field. In the low voltage sweeping region, gradual increase and/or decrease in resistance can also be observed, indicating that an analog type of switching behaviour similar to the first demonstrated memristor device has also been observed in the newly made device. This study could open up new ways for the design of multi-functional devices which are promising for memory and neuromorphic computing applications.
Study on the Influence of the Migration of Heavy Metals in 50Cr15MoV Kitchen Knives
Authors: Chen Jiaxin , Chen Yuan , Lin Hehai
Published: October 2020

25 batches of 50Cr15MoV kitchen knives were analyzed by chemical composition analysis, surface roughness testing, corrosion resistance testing, metallographic examination, scanning electron microscopy. The results show that:(1) there is no linear relationship between the heavy metal migration of 50Cr15MoV kitchen knives and its corresponding element content, and there is no correlation between the heavy metal migration and the surface roughness; (2) The heavy metal migration of kitchen knives is significantly correlated with corrosion resistance, and the heavy metal migration is positively correlated with the corrosion points in statistics; (3) The heavy metal migration of the kitchen knives with the same material of 50Cr15MoV varies greatly, which is closely related to the microstructure of the kitchen knives. The morphology and distribution of carbide microstructure and the heat treatment process of products have great influence on the heavy metal migration of kitchen knives.
Memristive Behaviour of Ag-doped-HfO2 Thin Films Prepared by Magnetron Sputtering
Authors: Chen Pengyu , Ilyas Nasir , Li Chunmei , Li Dongyang , Jiang Xiangdong , Li Wei
Published: October 2020

The bipolar resistive switching is suitable for the applications of information storage, logical operation and neuromorphic computation. This paper reports the bipolar resistive switching behaviour in HfO2:Ag-based memristive device. Under DC sweeps, the Ag/HfO2:Ag/p++-Si device showed a uniform bipolar resistive switching feature with a resistance ratio of ~15. Moreover, in the low voltage sweeping region, the device showed analog resistive switching behaviour with gradual SET and gradual RESET characteristics. It is suggested that the formation/rupture of Ag-filament is crucial in the resistive switching, and the gradual changes in resistance might have resulted from the dissolution of Ag atoms from active Ag top electrode (TE) rather than only from local migration of Ag atoms inside the dielectric layer. This new memristor structure with the analog resistive switching is expected for the future application of memristor as a nonvolatile memory and neuromorphic computing.
Penetration Behavior of Wp/Zr-based Amorphous Matrix Composite
Authors: Su Xiaohong , Hu Huie , Kong Xiaodong , Deng Jingxin
Published: October 2020

The penetration ability and penetration behavior of 50% Wp/Zr41.2Ti13.8Cu12.5Ni10Be22.5 amorphous matrix composite were studied through penetration test and microtopography observation. It is concluded that: the composite projectile shows self-sharpening behavior when penetrating 30CrMnMo steel target and 6061 aluminum target, especially after penetration of the aluminum target, the phenomenon of self-sharpening is obvious. 50% W particles added greatly improves the penetration performance of the composite. In the process of high-speed collision between the composite projectile and the target, the high temperature causes the amorphous alloy Zr41.2Ti13.8Cu12.5Ni10Be22.5 with low melting point to melt and cover on the surface of the crater.
Electrical Behavior against Current Impulse in ZnO Varistor Ceramics with SiO2 Addition
Authors: Wang Bowen , Fang Zhen , Fu Zhiyao , Peng Yongjing
Published: October 2020

SiO2 addition effect on electrical behaviour against current impulse in the ZnO varistors was investigated. SiO2 acts as a controller in ZnO grain growth, decreasing the grain size of ZnO from 8.87 to 5.86 μm, which in turn results in an increase in breakdown voltage E1mA
from 192.77 to 252.57 V/mm. SiO2 has a significant influence on the current energy withstand capability and impulse aging characteristics. The results indicated that the SiO2 content was optimized at 1.5 mol%, exhibiting the best energy withstand capability of 332.03J/cm3 and clamping ratio of 1.71.
Reviews on Interfacial Properties of the Carbon Fiber Reinforced Polymer Composites
Authors: Liu Fangbiao , Wang Danyong , Liu Juncong , Wei Huazhen , Zhang Haiyun , Xu Jingli , Li Shuhu , Qin Zhenming , Wang Ronghui , Jia Huamin , Zhang Jianqin
Published: October 2020

The bonding state between the carbon fiber and the polymer directly affects the properties of carbon fiber reinforced polymer composites (CFRP), which is influenced by the surface structural characteristics of carbon fiber (CF). The surface of CF is composed of tightly packed graphite crystallites lacking active carbon atoms, which results in low surface energy of CF and weak interfacial performance of CFRP. The interfacial properties can be evaluated indirectly through macro-mechanical properties, and can also be characterized by micromechanical testing methods. In order to improve the interfacial combination between the carbon fiber and the polymer, it is usually to modify the interface of CFRP, which mainly includes carbon fiber surface functionalization, carbon fiber surface coating and introduction of micro-nano enhancement phase. In this paper, researches on the interfacial properties of CFRP were reviewed, and the existing problems and the future research focus were also discussed.
Mix Design and Strength Properties of Full Iron Tailings Concrete
Authors: Duan Yajing , Sun Jianheng , Dun Chenyang , Guo Yao , Ma Xinxin , Yang Mingjing
Published: October 2020

In this paper, the iron tailings powder, iron tailings sand and iron tailings gravel in Qian’an city are used to replace fly ash, river sand and gravel respectively as admixture, fine and coarse aggregates of concrete. Through mix design, the high-fluidity concrete with strength grade C25, C30 and slump of 180~200mm is prepared. The compressive strength of all kinds of concrete with iron tailings powder as admixture can meet the requirements of the corresponding strength grade. The basic strength properties of full iron tailings concrete are more prominent in all kinds of concrete with iron tailings powder as admixture, and are the closest to that of fly ash concrete.
Selective Recognition of Fe3+ by a Simple Schiff Base Chemosensor
Authors: Liu Zhilian , Wang Mengqi , Liu Hui , Liu Wei , Zhang Qiang , Wang Xiaoyan , Zhao Hao , Dai Xinran , Deng Ziwei , Chen Pingping , Min Gao , Yuan Mengting , Wang Tengfei , Zhang Shuxiang
Published: October 2020

A simple and easily synthesized Schiff base chemosensor 1 was prepared by the one-step condensation reaction of 3-acetyl-4-hydroxycoumarin and 1-naphthylamine. The metal ion recognition ability of the chemosensor was measured by UV-Vis spectrophotometer. It demonstrated that its absorbance at 327 nm enhanced upon addition of Fe3+ significantly. The absorption intensities at 327 nm fitted good linear relation (R
2=0.9928) to Fe3+ concentration in DMF. 1 is able to recognize Fe3+ selectively over other ions. The synthesized chemosensor 1 would be useful to detect Fe3+ qualitatively and quantitatively.
Study on Hydration Resistance of MgAlON Composites
Authors: Guo Yanqin , Ji Zhe
Published: October 2020

Selected Aggregate, matrix and a small amount of sintering aids as raw materials. Mixed raw materials evenly, Sintered in high temperature nitriding furnace. Two test samples series of hydration resistance were made. Measured the pH value of the hydration samples, the content of nitrogen before and after hydration; drawn the change curve of pH value; calculated the weight change rate of samples before and after hydration; detected the phase composition of block sample before and after hydration. The results show that: under the same process conditions, the hydration resistance of MgAlON composite with spinel as aggregate is better than that of MgAlON composite with magnesia as aggregate. Compared with the sample of the same aggregate, the hydration resistance of the alumina based sample is better than that of the bauxite based sample. The phase composition of samples is almost unchanged before and after hydration, The reason for hydration is mainly due to the hydration of a small amount of AlN in the sample. The hydration resistance of MgAlON composites is much better than that of AlN composite.
Study on Wear-resistant Surfacing Flux Cored Wire for Shield Machine Hob
Authors: Su Banghe , Sun Junshen , Xu Hu , Jiao Enli , Zuo Zengmin
Published: October 2020

The hob is an important tool for the shield machine, which improves its wear resistance and is of great significance for extending its life and improving the reliability of the shield machine. Based on the working condition of the hob, Ni-Cr-B-Fe surfacing flux-cored wire was designed. The effects of Ni and B content on the microstructure and properties of deposited metal were studied by XRD and SEM. Optimize Ni and B content to provide technical data. The powder 40%Ni-10%Cr-50%Fe-B alloy flux-cored wire studied was used for hob surfacing, which significantly improved its wear resistance.
Study on the Seismic Behavior of Eccentrically Braced Steel Frames of Replaceable Shear Links With Web Opening
Authors: Li Tong , Shi Qiang , Wang Xinwu , Ye Chongyang
Published: October 2020

The replaceable energy-dissipating beam is convenient for post-earthquake repair and reinforcement or direct replacement. A quasi-static test study of an eccentrically supported steel frame with replaceable energy dissipating beam sections was performed, and the hysteretic performance and failure mode of the eccentrically supported steel frame with replaceable energy dissipative beam sections were obtained. Based on the test results, the structure of the energy dissipating beam segment was improved, and a number of K-shaped eccentric support frame finite element models for the web opening ratios of different energy dissipating beam segments were established. Nonlinear numerical analysis was performed on its hysteretic performance. The research shows that the finite element analysis is in good alignment with the test results. The opening of the web in the energy-consuming beam segment can effectively reduce the stress level of the frame beam and ensure that large plastic deformation occurs within the energy-consuming beam segment. With the increase of the opening ratio, the ultimate bearing capacity, initial stiffness and energy consumption of the frame have all shown a downward trend. The research provides a basis for the seismic design of similar structures and can guide the design of related projects.