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61.
The selective surface oxidation of the Ti-stabilized interstitial free (Ti-IF) and dual phase (DP) steel during recrystallization annealing at 820 °C under the variety of exposure time and composition of protective H2-N2 atmosphere at low dew point (−40 °C) was examined. It was found that Mn, Al, Si and Cr oxides are formed in all cases, but higher Mn and Si concentration in DP steel leads to an increase in a density of coarse nonwettable MnSiO3 particles. An increase in annealing time enhances surface coverage with oxides, while increased H2 content in gas atmosphere results in less coverage with external oxides improving the wettability. The influence of the stronger reducing atmosphere is more exhibit on Ti-IF steel where after 120 s of annealing in 15vol.%H2-85vol.%N2 atmosphere the wetting angle θ stabilized to a value of the order of 6°. The presence of surface BN and the TiN particles also affects the full surface coverage by external oxides. 相似文献
62.
Silvia Nappini Danil W. Boukhvalov Gianluca D'Olimpio Libo Zhang Barun Ghosh Chia‐Nung Kuo Haoshan Zhu Jia Cheng Michele Nardone Luca Ottaviano Debashis Mondal Raju Edla Jun Fuji Chin Shan Lue Ivana Vobornik Jory A. Yarmoff Amit Agarwal Lin Wang Lixue Zhang Federica Bondino Antonio Politano 《Advanced functional materials》2020,30(22)
By means of theory and experiments, the application capability of nickel ditelluride (NiTe2) transition‐metal dichalcogenide in catalysis and nanoelectronics is assessed. The Te surface termination forms a TeO2 skin in an oxygen environment. In ambient atmosphere, passivation is achieved in less than 30 min with the TeO2 skin having a thickness of about 7 Å. NiTe2 shows outstanding tolerance to CO exposure and stability in water environment, with subsequent good performance in both hydrogen and oxygen evolution reactions. NiTe2‐based devices consistently demonstrate superb ambient stability over a timescale as long as one month. Specifically, NiTe2 has been implemented in a device that exhibits both superior performance and environmental stability at frequencies above 40 GHz, with possible applications as a receiver beyond the cutoff frequency of a nanotransistor. 相似文献
63.
Ivana Vobornik Anan Bari Sarkar Libo Zhang Danil W. Boukhvalov Barun Ghosh Lesia Piliai Chia-Nung Kuo Debashis Mondal Jun Fujii Chin Shan Lue Mykhailo Vorokhta Huaizhong Xing Lin Wang Amit Agarwal Antonio Politano 《Advanced functional materials》2021,31(52):2106101
The emergence of Dirac semimetals has stimulated growing attention, owing to the considerable technological potential arising from their peculiar exotic quantum transport related to their nontrivial topological states. Especially, materials showing type-II Dirac fermions afford novel device functionalities enabled by anisotropic optical and magnetotransport properties. Nevertheless, real technological implementation has remained elusive so far. Definitely, in most Dirac semimetals, the Dirac point lies deep below the Fermi level, limiting technological exploitation. Here, it is shown that kitkaite (NiTeSe) represents an ideal platform for type-II Dirac fermiology based on spin-resolved angle-resolved photoemission spectroscopy and density functional theory. Precisely, the existence of type-II bulk Dirac fermions is discovered in NiTeSe around the Fermi level and the presence of topological surface states with strong (≈50%) spin polarization. By means of surface-science experiments in near-ambient pressure conditions, chemical inertness towards ambient gases (oxygen and water) is also demonstrated. Correspondingly, NiTeSe-based devices without encapsulation afford long-term efficiency, as demonstrated by the direct implementation of a NiTeSe-based microwave receiver with a room-temperature photocurrent of 2.8 µA at 28 GHz and more than two orders of magnitude linear dynamic range. The findings are essential to bringing to fruition type-II Dirac fermions in photonics, spintronics, and optoelectronics. 相似文献
64.
The paper presents a phenomenological model, which accounts for the observed similarity between change in the imaginary electrical impedance maximum (IIM) during the cure of a commercial epoxy system, RTM6, and the cure reaction rate data collected by differential scanning calorimetry (DSC) experiments on the same resin. The model is developed by analysing the information content of dielectric cure monitoring signals and calorimetric cure monitoring signals under both isothermal and non-isothermal cure conditions. The absolute values of the coefficients in the model equation are shown to be indicative of the relative effects of the polymerisation reaction and of the temperature on the dielectric signal. The information presented here strengthens the suggestion that on-line dielectric measurements may be used to quantify the degree of cure in thermosetting resins in real time. 相似文献
65.
Ketonization of Proline Residues in the Peptide Chains of Actinomycins by a 4‐Oxoproline Synthase 下载免费PDF全文
Dr. Siamak Semsary Dr. Ivana Crnovčić Ronja Driller Dr. Joachim Vater Dr. Bernhard Loll Dr. Ullrich Keller 《Chembiochem : a European journal of chemical biology》2018,19(7):706-715
X‐type actinomycins (Acms) contain 4‐hydroxyproline (Acm X0) or 4‐oxoproline (Acm X2) in their β‐pentapeptide lactone rings, whereas their α ring contains proline. We demonstrate that these Acms are formed through asymmetric condensation of Acm half molecules (Acm halves) containing proline with 4‐hydroxyproline‐ or 4‐oxoproline‐containing Acm halves. In turn, we show—using an artificial Acm half analogue (PPL 1) with proline in its peptide chain—their conversion into the 4‐hydroxyproline‐ and 4‐oxoproline‐containing Acm halves, PPL 0 and PPL 2, in mycelial suspensions of Streptomyces antibioticus. Two responsible genes of the Acm X biosynthetic gene cluster of S. antibioticus, saacmM and saacmN, encoding a cytochrome P450 monooxygenase (Cyp) and a ferredoxin were identified. After coexpression in Escherichia coli, their gene products converted PPL 1 into PPL 0 and PPL 2 in vivo as well as in situ in permeabilized cell of the transformed E. coli strain in conjunction with the host‐encoded ferredoxin reductase in a NADH (NADPH)‐dependent manner. saAcmM has high sequence similarity to the Cyp107Z (Ema) family of Cyps, which can convert avermectin B1 into its keto derivative, 4′′‐oxoavermectin B1. Determination of the structure of saAcmM reveals high similarity to the Ema structure but with significant differences in residues decorating their active sites, which defines saAcmM and its orthologues as a distinct new family of peptidylprolineketonizing Cyp. 相似文献
66.
p-Nitrophenol removal by combination of powdered activated carbon adsorption and ultrafiltration - comparison of different operational modes 总被引:1,自引:0,他引:1
Ultrafiltration is classified as a low-pressure membrane technology which effectively removes particulate matter and microorganisms and to a certain extent dissolved organic matter (15-25%) and colour. The technology has been optimized and is becoming competitive compared to conventional processes for larger scale plant capacities. In combination with activated carbon it is an effective barrier regarding the removal of synthetic organic chemicals. Growing interest in ultrafiltration raises the question of better usage of the adsorption capacity of powdered activated carbon (PAC) used in combination with this low-pressure membrane technique. This paper presents a pilot plant study of different PAC dosing procedures within a combined hybrid membrane IN/OUT process for removal of p-nitrophenol (PNP) from water (c(0)=1mg/L) under real case conditions (e.g. usage of the same module for the whole duration of the experiment, backwashing with permeate water, no separate saturation of the membrane with substance without presence of carbon). p-Nitrophenol was chosen as an appropriate test substance to assess the efficiency of different operation modes. Dead-end and cross-flow filtration were compared with respect to different PAC dosing procedures: continuous dosing into a continuously stirred tank reactor (CSTR) in front of the module and direct dosing into the pipe in front of the module (continuous, single-pulse and multi-pulse dosing). There was no advantage in cross-flow mode over dead-end referring to PNP concentration in the permeate. Relating to the carbon dosing procedure, the best results were obtained for continuous PAC addition. The option of dosing directly into the pipe has the advantage of no additional tank being necessary. In the case of single-pulse dosing, the formation of a carbon layer on the membrane surface was assumed and an LDF model applied for a simplified estimation of the "breakthrough behaviour" in the thus formed "PAC filter layer". 相似文献
67.
Soil gas radon, indoor radon and gamma dose rate in CZ: contribution to geostatistical methods for European atlas of natural radiations 总被引:1,自引:0,他引:1
A comparison of Czech indoor radon data, soil gas radon dataand gamma dose rate was performed on the data sets of 92 276indoor radon measurements in existing dwellings (National RadiationProtection Institute – NRPI), database of 9500 test sitesof soil gas radon measurements (Czech Geological Survey –CGS) georeferenced to levels of gamma dose rate map. Three methodswere used for the study of soil gas Rn–indoor Rn relationship:(1) based on the vectorised point soil gas and indoor data relatedto vectorised areas of gammadose rate, (2) vectorised soil gas–indoordata based on vectorised geological units and (3) soil gas andindoor data related to grid squares 10 x 10 km2. The first andsecond methods seem to express the closer correlation comparedwith the third one, however the correlation using the thirdmethod is influenced by the representativeness of data valuein the square of 100 km2 area. On the other hand, the thirdmethod can be used for the overview coverage of the continentalareas with lack of input information. 相似文献
68.
Abazović ND Montone A Mirenghi L Janković IA Comor MI 《Journal of nanoscience and nanotechnology》2008,8(2):613-618
In this study, nitrogen-doped titanium dioxide (TiO2) powders were synthesized in two ways: by heating of titanium hydroxide with urea and by direct hydrolysis of titanium tetraisopropoxide (TTIP) with ammonium hydroxide. The samples were characterized by structural (XRD), analytical (XPS), optical (UV/Vis absorption/reflection and Raman spectroscopy) and morphological (SEM, TEM) techniques. The characterization suggested that the doped materials have anatase crystalline form without any detectable peaks that correspond to dopants. The absorption threshold of titanium dioxide was moved in the visible range of optical spectrum from 3.2 eV to 2.20 eV. Particle sizes of synthesized powders were obtained from XRD measurements and from TEM data ranging from 6-20 nm. XPS and Raman spectroscopy were used for detection of nitrogen in doped samples. 相似文献
69.
Dragana Fabris Ivana Karmeli Hasan Muharemovi Tomislav Sajko Mia Jurilj Slavica Poto
ki Ruer Novak
eljka Vukeli 《International journal of molecular sciences》2021,22(16)
Gangliosides serve as antitumor therapy targets and aberrations in their composition strongly correlate with tumor growth and invasiveness. Anaplastic ganglioglioma is a rare, poorly characterized, malignant neuronal–glial tumor type. We present the first comparative characterization of ganglioside composition in anaplastic ganglioglioma vs. peritumoral and healthy brain tissues by combining mass spectrometry and thin-layer chromatography. Anaplastic ganglioglioma ganglioside composition was highly distinguishable from both peritumoral and healthy tissue despite having five to six times lower total content. Ten out of twelve MS-identified ganglioside classes, defined by unique glycan residues, were represented by a large number and considerable abundance of individual species with different fatty acid residues (C16–C24) in ceramide portions. The major structurally identified class was tumor-associated GD3 (>50%) with 11 species; GD3 (d18:1/24:0) being the most abundant. The dominant sphingoid base residue in ganglioside ceramides was sphingosine (d18:1), followed by eicosasphingosine (d20:1). The peritumoral tissue ganglioside composition was estimated as normal. Specific ganglioside composition and large variability of ganglioside ceramide structures determined in anaplastic ganglioglioma demonstrate realistic ganglioside expression patterns and correspond to the profile of high-grade malignancy brain tumors. 相似文献
70.
We show what we believe to be a novel way to use silicon in infrared radio communication as a suitable material for the realization of optical diffusers in the range of 850-1600 nm. A crystalline silicon wafer is made porous by means of electrochemical etching. The porous silicon produced is optically characterized, and measurements report a high reflectance in the band of interest. We also study the angular distribution of diffused radiation by the porous silicon surface at different angles of incident radiation. Measurements show that radiation diffuses in a quasi-Lambertian manner, confirming the good performance of this material as an incident radiation diffuser. 相似文献