bluuebunny/crossref_metadata_2025 huggingface dataset:
Controlling photocurrent channels in scanning tunneling microscopy
Authors: Schröder Benjamin , Bunjes Ole , Wimmer Lara , Kaiser Katharina , Traeger Georg A , Kotzott Thomas , Ropers Claus , Wenderoth Martin
Published: February 2020

We investigate photocurrents driven by femtosecond laser excitation of a (sub)-nanometer tunnel junction in an ultrahigh vacuum low-temperature scanning tunneling microscope (STM). The optically driven charge transfer is revealed by tip retraction curves showing a current contribution for exceptionally large tip-sample distances, evidencing a strongly reduced effective barrier height for photoexcited electrons at higher energies. Our measurements demonstrate that the magnitude of the photo-induced electron transport can be controlled by the laser power as well as the applied bias voltage. In contrast, the decay constant of the photocurrent is only weakly affected by these parameters. Stable STM operation with photoelectrons is demonstrated by acquiring constant current topographies. An effective non-equilibrium electron distribution as a consequence of multiphoton absorption is deduced by the analysis of the photocurrent using a one-dimensional potential barrier model.
Local growth of planar rhombus tilings
Authors: Fernique Thomas , Galanov Ilya
Published: February 2020

This paper is motivated by the issue of quasicrystal growth. It describes a simple local algorithm which appears to grow an infinite family of aperiodic tilings. Starting from a seed, tiles are added one by one at randomly chosen sites. A tile is added only if there is only one way to do this so that no forbidden local configuration is created. This algorithm rapidly grows large round-shaped patterns, up to a proportion of missing tiles which can be made arbitrarily small by taking a large enough seed.
From a single slit to periodic, modulated, and quasiperiodic crystals – a physical space diffraction analysis of aperiodic systems
Authors: Strzałka Radosław , Bugański Ireneusz , Śmietańska Joanna , Wolny Janusz
Published: February 2020

Using a statistical approach to diffraction analysis, it was shown that the scale of difficulty in the analysis of the diffraction image of a one-dimensional quasicrystal is not significantly different from the analysis of the diffraction image for a single slit. In both cases we get a rectangular probability distribution, for which the Fourier transform leads to analytical expressions on the envelopes of diffraction peaks expressed by means of simple trigonometric functions (sinc). The generalization to 2d (decagonal quasicrystals) and 3d (icosahedral quasicrystals) requires more complex calculations, but conceptually, it does not significantly differ from the calculations for model one-dimensional quasicrystals.
Bias-voltage dependent STM images from the 2–fold surface of the icosahedral Ag-In-Yb quasicrystal
Authors: Burnie Dominic , Coates Sam , McGrath Ronan , Sharma Hem Raj
Published: February 2020

The 2–fold surface of the icosahedral (i-)Ag–In–Yb quasicrystal has been investigated using scanning tunnelling microscopy (STM). STM data reveals a bias-voltage dependency. At high positive bias, bright protrusions are observed. At negative bias, new protrusions appear while the size of the original protrusions decreases. The STM features at both positive and negative bias polarities can be related to atomic planes intersecting the centre of Tsai-type clusters (the building blocks of the bulk structure). The bias-dependency can be explained by a change in contribution in tunnelling current from Yb and Ag/In, as expected from density of states calculations.
Phasonic Diffusion and Self-confinement of Decagonal Quasicrystals in Hyperspace
Authors: Hielscher Johannes , Martinsons Miriam , Schmiedeberg Michael , Kapfer Sebastian C.
Published: February 2020

We introduce a novel simulation method that is designed to explore fluctuations of the phasonic degrees of freedom in decagonal colloidal quasicrystals. Specifically, we attain and characterise thermal equilibrium of the phason ensemble via Monte Carlo simulations with particle motions restricted to elementary phasonic flips. We find that, at any temperature, the random tiling ensemble is strongly preferred over the minimum phason-strain quasicrystal. Phasonic flips are the dominant carriers of diffusive mass transport in physical space. Sub- diffusive transients suggest cooperative flip behaviour on short time scales. In complementary space, particle mobility is geometrically restricted to a thin ring around the acceptance domain, resulting in self-confinement and persistent phasonic order.
Stability of particles in two-dimensional quasicrystals against phasonic perturbations
Authors: Martinsons M , Schmiedeberg M
Published: February 2020

We investigate particles in two-dimensional quasicrystalline interference patterns and present a method to determine for each particle at which phasonic displacement a phasonic flip occurs. By mapping all particles into characteristic areas of reduced phononic and phasonic displacements, we identify the particles that are close to edges of these areas and can easily flip. In contrast, the particles in the center are hardly affected by phasonic fluctuations. Our results are important e.g. for light-induced colloidal structures or cold atomic gases in laser traps. In addition, our approach can help to predict how thermal fluctuations induce phasonic flips in intrinsic quasicrystals with structures close to interference patterns.
The effects of afforestation as an adaptation option: a case study in the upper Chao Phraya River basin
Authors: Takata Kumiko , Hanasaki Naota
Published: February 2020

The risks of flood and drought have been projected to increase in many regions due to global warming. Afforestation is considered an adaptation option because it reduces flood risks by decreasing total runoff and peak river discharge, but it also exacerbates drought risks by increasing evapotranspiration. In this study, both effects of afforestation were evaluated in comparison with changes caused by climate warming from the viewpoint of an adaptation measure, using a land surface model. The upper Chao Phraya River basin was taken as a case study. The present climate was set as a base condition and future climate conditions projected by the moderate (RCP4.5) and strong (RCP8.5) warming scenarios in the middle and late 21st century were used. The effects of afforestation were much smaller than the changes caused by warming even with the extreme forest area expansion and soil property changes. The effect of afforestation that reduced runoff was marked in the wet season, whereas the effect of afforestation that increased evapotranspiration was noticeable in the dry season leading to little increase in dry-season runoff. These results indicate that both the decrease in runoff that reduces flood risks in the wet season and the increase in evapotranspiration that exacerbates drought risks in the dry season should be taken into consideration when evaluating the hydrological effects of afforestation under global warming.
Melting scenario affects the dynamics of polycyclic aromatic hydrocarbons released from snowpack
Authors: Liu Shasha , Wang Zucheng , Xu Xiaoyun
Published: February 2020

Melting snowpack can release semi-volatile organic contaminants (SVOCs) to both terrestrial and aquatic ecosystems, resulting in high ecological risk. The dynamics of polycyclic aromatic hydrocarbon (PAH) released from snowpack under controlled laboratory (intense melting) and field (melt/freeze melyting) snowmelt experiments was investigated in this study. In the laboratory: dissolved organic carbon (DOC) controlled the first flush of dissolved PAHs released from snowpack, except for napthelene, which is also affected by its solubility. The particles released early from snowpack usually contained high PAH concentrations (more than 100 μg g−1) and those released at the end contained low PAH concentrations (<20 μg g−1). The total PAH release pattern was determined by composition of all PAHs, including type 2 enrichment with a final peak and type 4 enrichment with double-peak. In field melting: all dissolved PAHs were released constantly, except naphthalene, which also showed a first flush but to a lesser extent. DOC controlled the release pattern of all detected dissolved PAHs from snowpack. High PAH concentrations were observed in particles released from snowpack at both the beginning and the end of the melting event. Concentrations of both total PAHs and PAH compositions in meltwater showed an increasing trend with melting time (from 1.3 to 4.0 μg l−1 and from 1.7 to 5.3 μg l−1 in meltwater from each of the two snowpacks), which coincided with Type 3 enrichment. Overall, our results suggest intense melting of snowpack results in the shift of some hydrophobic PAH compositions from Type 2 to Type 4 enrichment, depending on their partition coefficients. In contrast, melting with melt/freeze cycles may cause the shift of PAHs from Type 2 to Type 3 enrichment. Our study indicates changes of the melting scenarios due to global warming could affect dynamics of SVOCs released from snowpack, which is useful for risk management for water and soil quality.
Long-term ecological consequences of forest fires in the continuous permafrost zone of Siberia
Authors: Kirdyanov Alexander V , Saurer Matthias , Siegwolf Rolf , Knorre Anastasia A , Prokushkin Anatoly S , Churakova (Sidorova) Olga V , Fonti Marina V , Büntgen Ulf
Published: February 2020

Wildfires are an important factor in controlling forest ecosystem dynamics across the circumpolar boreal zone. An improved understanding of their direct and indirect, short- to long-term impacts on vegetation cover and permafrost–vegetation coupling is particularly important to predict changes in carbon, nutrient and water cycles under projected climate warming. Here, we apply dendrochronological techniques on a multi-parameter dataset to reconstruct the effect of wildfires on tree growth and seasonal permafrost thaw depth in Central Siberia. Based on annually-resolved and absolutely dated information from 19 Gmelin larch (Larix gmelinii (Rupr.) Rupr.) trees and active soil layer thickness measurements, we find substantial stand-level die-off, as well as the removal of ground vegetation and the organic layer following a major wildfire in 1896. Reduced stem growth coincides with increased δ
13C in the cellulose of the surviving trees during the first decade after the wildfire, when stomatal conductance was reduced. The next six to seven decades are characterized by increased permafrost active soil layer thickness. During this period of post-wildfire ecosystem recovery, enhanced tree growth together with positive δ
13C and negative δ
18O trends are indicative of higher rates of photosynthesis and improved water supply. Afterwards, a thinner active soil layer leads to reduced growth because tree physiological processes become limited by summer temperature and water availability. Revealing long-term effects of forest fires on active soil layer thickness, ground vegetation composition and tree growth, this study demonstrates the importance of complex vegetation–permafrost interactions that modify the trajectory of post-fire forest recovery across much of the circumpolar boreal zone. To further quantify the influence of boreal wildfires on large-scale carbon cycle dynamics, future work should consider a wide range of tree species from different habitats in the high-northern latitudes.
Research progress of modified macroporous adsorption resin in adsorption separation
Authors: Sun Tao
Published: February 2020

Macroporous adsorption resin (MAR) is widely used in molecular adsorption and material separation due to its unique porous nature, surface activity and easy modification. Although there may be multiple synergistic effects in the adsorption process, its adsorption capacity is weak, and it is difficult to meet the problem of separation and purification of complex samples. The functional modification of macroporous adsorption resin is an ideal way to improve its separation efficiency and selectivity. In this paper, recent advances in the preparation of modified macroporous adsorption resins and their application in adsorption separation are reviewed, which provides a reference for further research.
Surface/Deep Defects manipulated Fluorescence Properties and LED application of Copper Nanoclusters
Authors: Ai Lin , Li Ji , Tang Min , Chen Hsiaohsien , Meng Hong
Published: February 2020

The contribution of metal defects to the emission enhancement of Cu nanoclusters has been proposed. But the insufficient understanding of the defects luminescence mechanism limits its further effective adjustment and control to the emission color. In this work, the surface metal defects of the assembled fluorescent materials are deliberately engineered. Metal defects have effects on luminescent energy levels, which are relative to the dynamic process of exciton radiation transition and regulate the photophysical properties of the materials. Further studies demonstrate the surface metal defects possess shallow energy level and multi sublevels, broaden the emission colors. Moreover, the continuous alteration of emission color is achieved by simply adjusting the relative ratio of the surface and deep metal defects. Based on the full-color emission of copper clusters, the white light emitting diodes (WLEDs) with different color temperatures (warm, cold, and pure white) are prepared for illumination application.
Chemical Fixed Point Sealing Technology in Oil Well
Authors: Zhang Lili , Yan Haijun , Hao Huijun , Xie Gang , Wei Aijun , Wei Lili , Sun Lei , Wang Hongfeng
Published: February 2020

When most oil fields have entered high water cut stage, the distribution of oil and water is more and more complex. Profile control and water shutoff is an important technology for water control and oil stabilization. Some types of water invasion in special reservoirs such as bottom water coning or edge water propelling in horizontal wells, water invasion in micro facture and big pore carry more challenges for profile control and water shutoff technology. Beyond that this technology is also affected by the plugging agent injection’s uncertainty and migration randomness. On the basis of earlier research, this paper introduces the plugging agent formulas, technology and field application of three types of technologies which are as follows, casing channeling treatment technology, water invasion plugging technology in interlayer and water invasion in horizontal well. The three types of fixed point sealing technology can achieve the accurate injection of shutoff agent and good results had obtained in site test.
Finite element analysis of damage region of CBM well based on underbalance reconstruction technology
Authors: Bao Xitao , Yang Jiang , Yan Yifei , Yan Xiangzhen
Published: February 2020

The reserves of coalbed methane (CBM) in China are very high. But the characteristics of “three low” (low pressure, low permeability, low porosity), thin formation and shallow burial depth for the CBM reservoirs may cause problems of long production cycle and slow increase in production. For above problems, a new reconstruction method for coal bed methane formation named underbalance reconstruction was introduced. By this method, a jet generator was lowered to perforated interval. Then, with the nitrogen injected and blowout, reconstruction results of coalbed reservoir can be achieved. Considered the process of underbalance reconstruction, coalbed reservoir properties and mechanical properties of coalbed, mechanical model of coalbed methane well was built and analyzed by finite element method. Afterwards, damage area of different nitrogen injecting cycle can be characterized. And the effect of underbalance reconstruction for coal bed methane formation can be obtained. Then, parameters of reconstruction technology can be optimized and optimization scheme can be supplied for the underbalance reconstruction for coal bed methane formation.
Analysis of Disaster Gas Accumulation Characteristics in Local Area of Upper Corner Based on Entropy Variable Dissipative Structure Model
Authors: Wei Yin-shang , Liu Pei-yao , Jia Yu-quan
Published: February 2020

This paper takes the angle CO of the 1406 working face of Fengjiata Coal Mine as main research object, by combining field measurement, theoretical research and numerical simulation, to explore essence of energy dissipation during gas accumulation in the upper lag zone and seek effective governance solutions. The result shows that the irreversible process such as eddy current loss caused by the spatial morphology of the upper sag angle is an important cause of gas accumulation. Thus, a flexible inflatable airbag for mining to change local ventilation mode is proposed and designed. The numerical simulation method is used to verify the venting of the mine inflatable airbag, which helps significantly eliminate the eddy current phenomenon in the lag zone.
A Review on the Molecular Mechanism, Superiorities, Appli-cations, Limitations and Experimental Workflow of CRISPR/Cas-9 System, and the Future of Gene Engineering
Authors: Wang Xiaoke
Published: February 2020

Gene engineering has been in development since the 1970s. The appearance of CRISPR/Cas-9 system, a gene engineering technology, even brought the wave of developing to its unprecedented peak. Meanwhile, the drastic growth and maturity of CRISPR made the public, represented by popular presses, to question the integrity and rightfulness of scientists to develop and apply CRISPR system, causing intense worldwide ethical battles of humanity. However, without relative knowledge background, rational and logical judgment can be hard to make. Us-ing qualitative research techniques, this research has thoroughly reviewed previous literatures that introduced the molecular mechanism, superiorities over other technologies, applications and limitations of CRISPR/Cas-9 system in order to give comprehensible introduction for the public. Using quantitative research methods, this research investigated the attitudes came from the pub-lic and science community toward the ethical issues around the use of gene engineering tools such as CRISPR in the form of numerical comparisons. More than 50% of people stand neutral in this battle, but there were more supporters of developing gene engineering technologies in the science community than that of in the public presses, which produces a necessity for countries to call for a pause of current developments, and to assemble national leaders to have a serious discussion.
Study on mechanical properties of cemented filling materials using by low-chlorine fly ash
Authors: Shi Tengyu , Zhang Siqi , Wen Ni , Li Keqing , Wang Ke , Ba Haojing
Published: February 2020

In this study, the blast furnace slag and desulfurized gypsum were used to make cementing materials, mixed with the tailings and fluidized bed municipal solid waste incineration(MSWI) fly ash to make high performance cementing filling material. The results show that: (1) The best ratio of test is low chlorine fly ash: slag: desulfurization gypsum = 20%: 68%: 12%, the MPC of cementing material is 82%, and the cement-sand ratio is 1:4, after curing for 28 days in a standard curing box with a curing temperature of 40°C and a relative humidity of 90%, the compressive strength reaches 22.81MPa, the flow rate reaches 240 mm. (2) The maximum amount of fly ash can reach 60%, after 28 days of curing, the sample strength is 8.70 MPa, the flow rate is 220 mm, both of which meet the requirements. (3) Comparing the slag system and cement system with 60% fly ash, it was found that the strength reached 10.36 MPa after 28 days of curing, the flow rate of the cement system was 215 mm, which did not reach the self-flow standard. It is possible to provide a low cost cementing filling material containing waste incineration fly ash in future.
Alkali treatment of bamboo powder mixed polypropylene and its effect on properties
Authors: Li Chenxin , Guo Weilin , Liu Chen , Shen Taoyi , Chen Tong , Wang Lijun , Kong Linxue
Published: February 2020

Bamboo powder (BP) was treated with different concentrations of alkali solution, and modified polypropylene material of bamboo powder/polypropylene blend was prepared. Using the scanning electron microscopy (SEM) and X-ray diffractometry (XRD) to study the effects of alkali treatment and various alkali concentrations on the micro-structure and mechanical properties of the modified polypropylene. The test results illustrate that the alkali treatment can remove the amorphous cement between lignocellulose, form more fine mesh structure, and increase the surface area, which is beneficial to improve the mechanical interlock between the fiber and the polymer matrix. Thus, improving the mechanics performance of composites by this method. As the increase of alkali solution concentration, the impact strength of bamboo powder/polypropylene composites show the trend of rising up and then descending. When the concentration of sodium hydroxide is 3%, the bamboo powder/polypropylene composite material has better normal temperature impact strength. When the sodium hydroxide concentration is 9%, the bamboo powder/polypropylene composite has the optimal yield strength.
Quantitative determination of Lisinopril Dihydrate in pharmaceutical preparations by direct potentiometriy
Authors: Bozhanov S , Smerikarova M , Maslarska V
Published: February 2020

A direct potentiometric titration method was applied for determination of Lisinopril Dihydrate. The method was based on the treatment of the primary data with nonlinear regression procedure. An accessible and easy-to-use algorithm for the evaluation (quantification) of a system with acid-base properties has been developed to provide a quick and unambiguous answer for the quantitative content of Lisinopril Dihydrate. The acid-base constants of Lisinopril Dihydrate were determined in aqueous solutions (at constant ionic strength 0.2 mol/l KCl and temperature 25°C). The potentiometric method developed was validated according to ICH and shows very good accuracy and precision. The present approach can be successfully used in routine analysis of the drug in quality control laboratories.
Label-free electrochemical aptasensor for GPC3 detection based on RGO-CS-Fc/Pt NPs
Authors: Li Yuqiu , Li Wenzhan , Li Guiyin
Published: February 2020

Glypican-3 (GPC3) is a promising biomarker of early detection of hepatocellular carcinoma (HCC). Herein, an label-free electrochemical aptasensor for the detection of GPC3 was developed based on reduced graphene oxide-chitosan-ferrocene/platinum nanoparticles (RGO-CS-Fc/Pt NPs). GPC3 aptamer (GPC3-Apt) was immobilized onto the surface of the modified screen-printed carbon electrode (SPE) by RGO-CS-Fc/Pt NPs. When the GPC3 was added to the platforms of aptasensor, the specific recognition reaction between the GPC3-Apt and GPC3 produced aptamer-antigen complex and arranged on the electrode surface, which made the change of electrochemical signals of Fc obtained by differential pulse voltammetry (DPV). Hence, the calibration graph (peak current vs GPC3 concentration) can be used for quantification of GPC3. The measured peak current and GPC3 concentration have a good linearity in the range of 0.05-10.0 μg/mL, a correlation coefficient of 0.9805 and a low detection limit of 0.018 μg/mL (S/N=3). Moreover, the designed aptasensor showed good performance with excellent selectivity, acceptable reproducibility and stability. Thus, this label-free electrochemical aptasensor has promising applications for the early detection of HCC.
Low Temperature Catalytic Performance of Manganese and Cerium Complex Oxide Catalyst towards Toluene
Authors: Wang Keliang , Liu Xiuzhen , Tu Shunheng , Zhang Le , Li Wen , Jiang Chan , Ye Daiqi
Published: February 2020

A series of MnOX(X)–CeO2 complex oxide catalysts with various Mn/Ce mole ratios were prepared successfully by sol-gel method and were characterized by BET, XRD, SEM, H2-TPR and XPS techniques, and the catalytic activity towards toluene were tested. The results showed that MnOX(X)–CeO2 complex oxide catalysts presented superior low temperature catalytic activity than pure CeO2 and MnOx, MnOx(0.6)-CeO2 exhibited the highest catalytic activity with T50=125°C and T99=197°C under the condition of GHSV of 10000h−1 and toluene concentration of 100ppm. The characterization results also indicated that the catalytic activity was relavant closely with specific surface area, catalyst morphology and valence of manganese oxides. Also, MnOX(X)–CeO2 formed solid solution with fluorite structure after the introduction of manganese, and produced quantities of manganese species, atom adsorbed oxygen and crystal oxygen, which promoted the adsorption and activation of gaseous oxygen and the mobility and transfer of active oxygen.
Effect of Different Reduction Methods on the Structure of Graphene Oxide
Authors: Feng Ting , Zheng Leilei , Huang Jin , Chu Zhen , Xue Dengrong , Liu Zhongxin
Published: February 2020

The samples of graphene oxide were prepared by Hummers method, and then they were reduced and dried by different methods. The effects of different treatment methods on the graphene oxide’s morphology, size and oxygen content were analysed by IR, Roman and TEM. The results show that the reduction method of increasing temperature can effectively reduce the oxygen content of graphene oxide but increase the defect density. However, the ultrasonic cell pulveriser can effectively reduce the oxygen content of graphene oxide in the reduction process and has little effect on the defect density. Therefore, low-defect and low-oxygen reduced graphene oxide can be quickly obtained by an ultrasonic cell pulveriser.
A label free colorimetric assay for detection of sulfite root based on Cu2+
Authors: Ma Yefei , Fu Xiaofen , He Wen , Gao Xing
Published: February 2020

The reaction between sulfite and hydrogen peroxide causes the absorbance decrease, which provides the basis to determine the sulfite content that is sensitive to the absorbance change. Cu2+can catalyze the chemical reaction between hydrogen peroxide (H2O2) and the 2,2’-Azinobis-(3-ethylbenzothiazoline-6-sulphonate) (ABTS) effectively, which will cause the change of absorbance. In this paper, we presented an experiment system to study the influence of pH value, H2O2content, Cu2+content and reaction time on the reaction system. The comparison of experiment system results indicated that the optimal condition was pH value of 7.0, H2O2of 500 μM, Cu2+of 250 μM and 5 minutes reaction time. Under the optimal conditions, the absorbance (Y) and SO32-content (C) have a linear relationship Y=-861.35C+0.8923. The coefficient of determination (R2) in the linear relationship is 0.9983, which indicates a strong correspondence between C and Y. Then, the established method was used to detect the sulfite in wine. The recovery rate was between 96.01% and 106.90%, which proves this method is efficient for sulfite determination.
A stable FHD display device based on BCE IGZO TFTs
Authors: Wan G M , Ge S M , Gong C , Li S , Lin X N
Published: February 2020

In this work, the impact of the deposition process of the SiOx passivation layer on the electrical properties of the BCE IGZO TFTs has been studied. The ΔVth of the TFTs are 2.52 and -1.67 V under PBTS (60°C, 30 V) and NBITS (60°C, -30 V, 4500 nit) after 1 hour, respectively. The stability of these TFTs is verified in 32in FHD display devices, which still could display the picture properly after the 500-hour aging test at 60°C and 90% humidity. A stable FHD display device based on BCE IGZO TFTs was achieved.
Study on the preparation of suspension stabilizer for liquid accelerator
Authors: Guan Mengqin , Li Xianghe , Guo Xinqi , Jiang Zhuojun
Published: February 2020

A suspension stabilizer (P-XF) was prepared by copolymerization of acrylamide (AM), acrylic acid (AA), ammonium persulfate (APS), thioglycolic acid (TGA) and potassium hydrogen tartrate (KHT). The suspension stabilizer (P-XF), aluminum sulfate (Al2(SO4)3), p-toluenesulfonic acid (PTSA) and triethanolamine (TEA) were used to prepare a liquid accelerator (P-SN2). The test results show that compared with the liquid accelerator (P-SN1) without P-XF, P-SN2 not only can effectively shorten the setting time, but also has high stability, with a stable period of more than one year.
Simulation and application of a new type of slideway beam based on MIDAS jacking construction method
Authors: Qin LI , Gao Jian , Zhang Qiuyue
Published: February 2020

In order to ensure the continuous box girder jacking method in the process of construction safety in Jingzhou City, Mongolia and China Railway Bridge jacking construction method of process engineering background, research on continuous box girder pushing process in the first two layer 8 laminated I-beam spell 56B security control problem model in the process of construction, the slide beam. Based on the control principle of adaptive method, a finite element model of slideway beam during incremental launching is built by MIDAS, and the range of deformation and internal force of the whole structure of slipway beam is put forward during construction. Through monitoring and measuring the deformation of the slideway beam during the incremental launching process, we get the test data and compare with the theoretical value, so as to guide the safety control of the slipway beam during the pushing construction of the continuous box girder. The research results show that during the incremental launching of continuous box girder, the slideway beam can meet the requirements of deformation and internal force. The safety control technology adopted can effectively guide the engineering construction, and the method is feasible.
Description of delaminations in composite multilayered structures – comparison of numerical and experimental results for compressed plates
Authors: Muc A.
Published: February 2020

The buckling loads and the post-buckling behavior of the perfect and imperfect delaminated plate are investigated in the paper. For this purpose the concise formulations enabling to derive pre- and post-buckling behaviour of plates with embedded delaminations is presented. The computations are made using FE package NISA II and Mathematica package. Obtained results for buckling loads and the post-buckling behaviour are compared with the experimental results. The Digital Image Correlation (DIC) technique is employed to verify the uniformity and homogeneity of deformations.
The features of bimetallic Pt-Ru nanoparticles formation on the Nafion membrane for electrodes of chemical power sources
Authors: Lebedeva M V , Ragutkin A V , Antropov A P , Yashtulov N A
Published: February 2020

In this work the electrode materials on Nafion modified by bimetal platinum-ruthenium nanoparticles have been formed. The functional characteristics of the electrodes have been studied by atomic force microscopy, scanning electron microscopy and voltammetry methods. The catalytic activity of the synthesized composites in the methanol oxidation reaction at different temperatures had been investigated.
Study of the addition of the hybrid sisal fibers on the dynamic mechanical property of SFs reinforced polylactic acid (PLA) composites
Authors: Zhu Z H , Zhang N , Zhang Y , Hao M Y , Wu H W
Published: February 2020

When sisal fiber (SF) is added into polylactide (PLA) matrix, the storage modulus of PLA/SF composites increases greatly which indicate the rigidity of the composite material increases obviously. Comparing PLA composites with pure PLA, it can be found that the glass transition temperature (Tg) of PLA composites is significantly higher than that of PLA which showed the heat resistance of the PLA composites can be improved obviously because of the addition of SFs in PLA matrix. The energy storage modulus of PLA/HSFs is the highest of all PLA composites. HSFs could improve the dynamic mechanical properties of PLA composites more significantly than ASFs and USFs.
Effects Analysis of Super Surfacing Pavement Performance Using Epoxy Modified Emulsified Asphalt as Bonding Layer
Authors: Xuejun Wen , Huang Ming
Published: February 2020

A large number of studies have shown that emulsified epoxy asphalt has good cohesion and is an ideal choice for road surface treatment technology. However, after emulsification, epoxy resin needs to be emulsified and modified in a very special way to form a good combination with other structural layers in different binders. Based on super surfacing treatment technology, the combination of epoxy resin emulsification and different emulsification modification methods was discussed. Referring to the latest precision design, three bonding methods were used to bond the surface and the underlying layer. That is, no bonding layer, emulsified asphalt bonding layer and epoxy emulsified asphalt bonding layer. The pavement performance comparison test of super surface asphalt mixture was carried out. SBR-A modified emulsified asphalt and SBR-B modified emulsified asphalt were selected as the most commonly used fine surface binder. After comprehensive mix proportion design, three key indicators of wear resistance, water damage resistance and skid resistance are selected to evaluate road performance. The test process and research results show that the epoxy emulsified asphalt binder has excellent pavement performance under the design of test gradation, and has good compatibility with SBR-A modified emulsified asphalt.
Comparison of Tensile and Impact Absorption properties of Bio-Inspired Helicoidal stacked with Cross-Ply Stacked Carbon Fiber Laminate
Authors: Lim Samuel W.Y. , Beng Soh Chew , Jian Hui Shawn Lim , Ho Paul
Published: February 2020

Herrigbone structures are identified on the chitins of the Mantis shrimp. Bio-inspired helicoidal arrangement of composite layers can mimic these herringbone structures. First, the carbon composite samples are fabricated using the hand lay-up method, followed by a curing process using a hot press system. The impact absorption properties of these samples will be analyzed through a series of impact tests. The samples will also be tested for its tensile properties to compare the effect of plies arranged in helicoidal [0,45,90], [0,30,60,90] and Cross-ply orientations to form the laminate structure. The results showed that helicoidal samples have higher penetration tolerance and toughness as compared to Cross-ply samples during impact tests. It is found that the specimen with helicoidal stacking sequence has better debonding resistance and improved damage tolerance. The 6-ply helicoidal samples exhibits higher tensile strength as compared to 6-ply Cross-ply samples due to better fiber to matrix adhesion for helicoidal structure in the direction of pulling force.
Repair feasibility of SS416 stainless steel via laser aided additive manufacturing with SS410/Inconel625 powders
Authors: Weng Fei , Liu Yongfeng , Chew Youxiang , Wang Leilei , Lee Bing Yang , Bi Guijun
Published: February 2020

Laser based additive manufacturing technique has been found beneficial in fabricating complex components efficiently. In this paper, laser aided additive manufacturing with powder feeding (LAAM) was used to deposit SS410 or Inconel625 on SS416 substrate. Interfacial microstructure and mechanical properties of the deposited samples are investigated accordingly. Results indicated that deposit without obvious defects can be obtained. The interface samples exhibit comparative or slight lower tensile strength compared with the SS416 substrate. Fracture tends to occur at the SS416 side, either far from the fusion line for the SS410/SS416 sample or near the heat affected zone (HAZ) for the Inconel625/SS416 sample. Therefore, the LAAMed section are reliable enough. SS410 or Inconel625 both can be used for repair of SS416 parts.
Interlaminar fracture toughness analysis of fiber reinforced metal laminates based on APDL
Authors: Zhi Zhu Gong , Liang Zheng Chang , Sheng Xia Dong , Fa Ren Ming
Published: February 2020

Fiber Reinforced Metal Laminates (FRMLs) are widely used in modern industry because of excellent comprehensive properties. However, due to the existence of the interface, there will be delamination damage in their use process. Interface is the weakest part of fiber reinforced metal laminates. The bonding strength at the interface is determined by the fracture toughness of the interface. It is an important mechanical property index of fiber reinforced metal laminates. It is usually measured by a single cantilever beam test. In this paper, the finite element model of fiber reinforced metal laminate was constructed based parametric design language APDL of ANSYS to simulate the fracture roughness tests of FRMLs using element birth-death technology. The results show that the numerical simulation is very close to the experimental results. The numerical simulation is a very effective method to determine the interlaminar fracture toughness of fiber reinforced metal laminates.
Study on properties of sisal fiber modified foamed concrete
Authors: Liu Yunxue , Wang Zhen , Fan Zhaorong , Gu Jin
Published: February 2020

Sisal fiber modified foamed concrete was prepared with ordinary Portland cement and vegetable protein foaming agent as the base material and sisal fiber as the modifier. The distribution of fibers in the sample changes. The results show that when the fiber content is 0.75% and the fiber length is 5mm, the mechanical properties of foamed concrete are improved most obviously, and the respectively. Sisal fiber can effectively improve the shrinkage of foamed concrete. The longer sisal fiber is, the smaller the drying shrinkage of modified foamed concrete is. From the optical photos of concrete, it can be seen that at the same mixing amount (1%), fibers with lengths of 5mm and 10mm are more evenly dispersed than those with lengths of 15mm, which have little impact on the bubble holes.
Preparation and evaluation mechanical, chemical and thermal properties of hybrid jute and coir fibers reinforced bio-composites using poly-lactic acid and poly-caprolactone blends
Authors: Hossen Md. Muzammel , Feng Jianyong , Yuxiang Yin , Jiang Wenbin
Published: February 2020

Green composites using thermoplastics and thermosets got immense popularity long back when it newly introduced to the industry due to diminishing reliance on oil-based or gasoline materials, which causes numerous environmental problems. In this paper, bio-composites mechanical, chemical, thermal, and degradation properties of hybrid jute and coir fibers reinforced polylactic acid (PLA) investigated. Throughout the fabrication procedure of biocomposites, jute, and coir fibers characterized into three different categories raw, alkali-peroxide, and alkali-silane combined chemical treatments followed a design containing in a total of ten optimized samples. Jute and coir fibers were mixed with a solution of polycaprolactone (PCL) for better fiber-matrix adhesion prior to fabrication. The mechanical properties of alkali-silane treated reinforced fibers biocomposites improved compared to untreated fibers, which exhibited for fiber contents 40% an increase of respectively 32.8% by tensile strength 25.95% by tensile modulus, 24.58% by flexural strength, 23.64% by flexural modulus, and 26.08% by impact strength. Besides, moisture absorption, thickness swelling, thermal stability (TG), and surface chemistry analysis (FTIR) properties investigated, according to fiber-matrix contents ratio, hot-pressing time, temperature, and pressure to identify the effect of biocomposites due to chemical treatments. Moreover, the fiber surface effect of chemical treatments and interfacial adhesion morphologies observed using SEM. Eventually, alkali-silane combined optimized samples demonstrated the most desirable result in every aspect. In addition, a 90 days burial degradation performed to see the degradation flow of the biocomposites.
Improvement of optical properties of Mg doped ZnO by nanostructuring for applications in optoelectronics
Authors: Khuili M , Fazouan N , Abou El Makarim H , Atmani E H , Houmad M
Published: February 2020

We have studied the structural, optical, electronic and electrical properties of pure and Mg doped ZnO nanosheets compared to bulk ZnO, using the Density Functional Theory (DFT) within the Full Potential Linearized Augmented Plane Wave (FP-LAPW) formalism. The calculated band structure, total and partial densities of states show that the ZnO nanosheet have a large band gap than the other found in the bulk ZnO, which increases with increasing concentration of Mg. The absorption coefficient and optical transmittance show a red-shift after doping ZnO, whereas, the reflectivity and electrical conductivity are reduced. These good optical properties of ZnO nanosheets make it promising in optoelectronic devices, especially in solar cell application.
Thermal properties of CsPbCl3 thin films across phase transitions
Authors: Haeger Tobias , Ketterer Moritz , Bahr Johannes , Pourdavoud Neda , Runkel Manuel , Heiderhoff Ralf , Riedl Thomas
Published: February 2020

The local thermal conductivity, thermal diffusivity, and volumetric heat capacity of cesium lead chloride perovskite thin films are mapped simultaneously and with highest spatial resolution by a scanning near-field thermal microscope. Both, the 3D phase (CsPbCl3) and the 0D phase (Cs4PbCl6) are investigated. For CsPbCl3 thin films the variation of the thermal properties across the phase transitions in the range from room-temperature to 65 °C are analyzed. While the thermal conductivity at room temperature is ultra-low, a significant increase of the thermal conductivity is found for the cubic phase of CsPbCl3 (T > 46 °C). While only slight variations in the thermal conductivity are detectable for transitions from the monoclinic to the orthorhombic to the tetragonal phase, thermal diffusivity and volumetric heat capacity measurements are extremely sensitive to the amount of heat involved in the respective transition. It is shown that upon transition to the cubic phase of CsPbCl3 thin films, the relative increase of the volumetric heat capacity is significantly higher than that of the thermal conductivity. Thus, the thermal diffusivity in the cubic phase becomes notably lower in comparison to that of the respective phase at room temperature. An increase of the volumetric heat capacity had been theoretically predicted earlier but could not be confirmed in previous experimental studies. The findings of our thermal analysis are of great general importance for fundamental material research and for the thermal design of thin-film devices based on CsPbCl3 perovskites.
Morphologic and Immunocytochemical Features of High-Grade Serous Carcinoma of Ovary in Ascitic Fluid Effusion and Fine-Needle Aspiration Cytology
Authors: Bansal Akriti , Srinivasan Radhika , Rohilla Manish , Sundaram Archana , Rai Bhavana , Rajwanshi Arvind , Suri Vanita , Saha Subhash C , Gupta Nalini , Gupta Parikshaa , Dey Pranab
Published: February 2020

Objectives

High-grade serous carcinoma (HGSC) is the most common ovarian malignancy. The role of cytopathology in obtaining tissue diagnosis before institution of neoadjuvant chemotherapy (NACT) was evaluated.

Methods

All histopathology-proven HGSC specimens between 2015 and 2018 with prior cytopathologic diagnosis by ascitic fluid evaluation or fine-needle aspiration (FNA) of ovarian mass were reviewed with cell block immunocytochemistry for CK7, CK20, PAX8, WT1, and p53.

Results

Of 288 cases of HGSC, pre-NACT cytology diagnosis was established in 32% (93/288), with specific HGSC diagnoses made on ascitic fluid in 88% (82/93) and by ovarian mass FNA in 12% (11/93). The ascitic fluid showed moderate/high cellularity with papillary clusters in 76% (71/93) cases. Cell block immunocytochemistry showed tumor cells positive for CK7, PAX8, and WT1. p53 showed mutant or null-type positivity in 65% (33/51) and 33% (17/51) of cases, respectively, with 100% concordance with subsequent histopathology specimens. Poor/intermediate response to chemotherapy was shown in 75% of cases.

Conclusions

Combined assessment of cytomorphology, cell block histomorphology, and ancillary immunohistochemical testing, including PAX8, WT1, and p53, allows for specific pre-NACT diagnoses of HGSC in ascitic fluid and ovarian FNA cytology. This practice allows for initiation of chemotherapy and diminution of disease burden prior to definitive surgical therapy.
Biomedical data and computational models for drug repositioning: a comprehensive review
Authors: Luo Huimin , Li Min , Yang Mengyun , Wu Fang-Xiang , Li Yaohang , Wang Jianxin
Published: February 2020

Drug repositioning can drastically decrease the cost and duration taken by traditional drug research and development while avoiding the occurrence of unforeseen adverse events. With the rapid advancement of high-throughput technologies and the explosion of various biological data and medical data, computational drug repositioning methods have been appealing and powerful techniques to systematically identify potential drug-target interactions and drug-disease interactions. In this review, we first summarize the available biomedical data and public databases related to drugs, diseases and targets. Then, we discuss existing drug repositioning approaches and group them based on their underlying computational models consisting of classical machine learning, network propagation, matrix factorization and completion, and deep learning based models. We also comprehensively analyze common standard data sets and evaluation metrics used in drug repositioning, and give a brief comparison of various prediction methods on the gold standard data sets. Finally, we conclude our review with a brief discussion on challenges in computational drug repositioning, which includes the problem of reducing the noise and incompleteness of biomedical data, the ensemble of various computation drug repositioning methods, the importance of designing reliable negative samples selection methods, new techniques dealing with the data sparseness problem, the construction of large-scale and comprehensive benchmark data sets and the analysis and explanation of the underlying mechanisms of predicted interactions.
A hotspot atop: rivers of the Guyana Highlands hold high diversity of endemic pencil catfish (Teleostei: Ostariophysi: Siluriformes)
Authors: Hayes Malorie M , Paz Holden J , Stout Carla C , Werneke David C , Armbruster Jonathan W
Published: February 2020

The Pakaraima Mountains are an ancient mountain range along the borders of Guyana, Brazil and Venezuela. The high plateau is drained by multiple river systems in all directions. Although hypotheses have been presented for the biogeographical relationships of lowland rivers, the interconnectivity of rivers on the top of the plateau is unknown. With multiple complex rivers in a small, upland area, we predicted a high level of endemism for stream fishes and complex biogeographical relationships. We explored this with the incredibly diverse pencil catfish genus Trichomycterus. Using collections from recent expeditions to the Pakaraima Mountains of Guyana, we amplified three mitochondrial (16S, COI and Cytb) and one nuclear marker (rag2). We constructed individual gene trees and a concatenated tree to determine the placement of these taxa within the Trichomycterus of the trans-Andean/Amazonian clade. Herein, we identify six endemic lineages of Trichomycterus from the highlands of the Pakaraima Mountains. Of the identified lineages, we find two species occupying multiple basins, suggesting that Pakaraima streams either maintain connectivity or had some degree of recent connectivity.