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Achieving uniform dispersion of nanofillers in a polymer matrix, particularly for incompatible compounds, remains a formidable challenge. In this study, thermally reduced graphene oxide (TrGO) sheets were effectively dispersed within a nonpolar polypropylene (PP) matrix using a two-step approach, leveraging the Friedel–Crafts reaction catalyzed by AlCl 3. The results showed that the size and number of TrGO aggregates were significantly reduced after AlCl 3 treatment. The thermo-oxidative stability in terms of oxidation induction time (OIT) of the PP/TrGO(Al) composite further improved by 2 times when 0.1 wt% TrGO was added to the PP matrix compared with that of the samples without AlCl 3 treatment. The improved thermo-oxidative stability and mechanical properties of PP/TrGO(Al) can be attributed to its superior radical scavenging efficiency, oxygen barrier effect, and effective load transfer afforded by the excellent dispersion of TrGO. This research highlights a pioneering methodology for enhancing both the dispersion of TrGO in a nonpolar polymer matrix and the thermo-oxidative resilience of the resultant composites. [Display omitted] • TrGO sheets were well-dispersed in PP matrix by using a two-step method through Friedel-Crafts reaction. • The thermo-oxidative stability of PP/TrGO(Al) composite were further improved due to the improvement of TrGO dispersion. • This can be attributed to the radical scavenging ability and oxygen-barrier effect of well-dispersed TrGO. [ABSTRACT FROM AUTHOR]

• Constant compressive stress promoted the fracture of polysulfide and disulfide bonds. • Reactive sulfur-containing side (RSS) groups were formed under compressive stress. • RSS groups could participate in re-crosslinking reactions in the presence of heat. • RSS groups increased the hysteresis loss of NR under deformation. The evolution process of the crosslinking structure in sulfur-cured natural rubber (NR) under the combined effect of compressive stress and temperature was investigated using a homemade constant-stress device. The aged NR samples were characterized by infrared spectroscopy, chemical probe method, differential scanning calorimetry, and mechanical analysis. The results revealed that compressive stress promoted the breakage of sulfur bonds (mainly low-energy ones) between NR chains, leading to a decline in crosslink density and an increase in mesh size. According to the Arrhenius equation, a compressive stress of 1.78 MPa reduced the apparent activation energy for the breakage of polysulfide bonds from 56.3 kJ/mol to 48.2 kJ/mol, resulting in a 14.4% decrease. The sulfur-containing side groups formed after the breakage of polysulfide bonds not only participated in post-crosslinking reactions after stress release but also increased the hysteresis loss of NR under large deformation. [ABSTRACT FROM AUTHOR]

Recently, great breakthroughs in natural gas exploration have been achieved in the Nanpu Sag, Bohai Bay Basin, eastern China; however, the genetic type and formation mechanisms of the gas are still unclear, impeding further exploration. Chemical and isotopic compositions were investigated to determine the origins for the gas. Three groupings of the natural gases are recognized: oil-type gas, coal-type gas, and mixed-source gas. The oil-type gases are relatively depleted in 13 C (δ 13 C 1 < −43‰); δ 13 C 2 < −29‰ and low wetness (0.60–0.89). The coal-type gases are enriched in 13 C (δ 13 C 1 > −40‰; δ 13 C 2 > −28‰) with higher wetness (0.80–0.95). The third grouping of gases exhibits intermediate molecular and isotopic values. Most of the gases in the shallow layers of the No. 1 and 4 structural belts have δ 13 C values similar to those of underlying gases and display evidence for microbial alteration. Primary cracking of kerogen is responsible for the generation of most of this gas. Pyrolysis of the source rocks combined with maturity estimations revealed that the relatively shallow oil-type gas was derived primarily from Oligocene and Eocene (Ed 3 –Es 1 ) source rocks bearing Type I–II 1 kerogen, whereas the coal-type gas was generated from the Eocene (Es 2+3 ) source rocks containing II 2 –III kerogen. We concluded that the kerogen type and maturity of the source rocks and the activity of source-connecting faults primarily controlled the distribution of the different gases. We suggest that there is significant deep gas potential in the Nanpu Sag, perhaps even over the whole Bohai Bay Basin, that would be prospective for further deep gas exploration in the area. [ABSTRACT FROM AUTHOR]

Three new oxidovanadium(V) complexes with formula [VOLL′] (L = L 1 = N ′-(2-hydroxy-4-methoxybenzylidene)-4-hydroxybenzohydrazide for 1 , L = L 2 = N ′-(3-ethoxy-2-hydroxybenzylidene)pivalohydrazide for 2 , L = L 3 = 2-bromo- N ′-(3-ethoxy-2-hydroxybenzylidene)benzohydrazide for 3 , L′ = ethylmaltol), have been prepared. The complexes have been characterized by physico-chemical methods and single crystal X-ray determination. The V atom in each complex is coordinated by the NOO donor atoms of L, the OO donor atoms of L′, and one oxido group, forming octahedral coordination. The complexes were administered intragastrically to both normal and alloxan-diabetic mices for two weeks. The biological activity results show that the complexes at doses of 10.0 and 20.0 mg V·kg −1 , can significantly decrease the blood glucose level in alloxan-diabetic mices, but the blood glucose level in the treated normal mices was not altered. [ABSTRACT FROM AUTHOR]

The wear damage and aging behavior of natural rubber (NR) nanocomposites are very complex under severe conditions (high load, high-speed wear, or ablation). Little is known about the influence of strong interfacial friction on the high-temperature aging mechanism in the internal of NR nanocomposites. In this study, a set of UMT-TriboLab wear tester was used to study the wear and aging of NR nanocomposites, and to reveal their influence on the internal aging of specimens under severe conditions. Sliding wear tests were carried out with rubber-metal tribopair using a Block-on-Ring configuration. Different from mild wear conditions, the wear mechanism of NR nanocomposites under severe conditions experienced a transition from abrasive wear to adhesive wear. The viscous film formed by the degradation products on the wear surface was found to strongly affect the subsequent wear and aging behavior (wear weight loss, friction coefficient, temperature rise, etc.) of specimens. Layer-by-layer analysis showed that the heat diffusion caused by surface wear resulted in noticeable post-crosslinking in the internal layer of specimens while the oxidation reaction was limited to occur only on the specimen surface. • The wear behavior of NR blocks was studied under high loads and high speeds. • The specimen surface underwent serious mechanical and oxidative degradation. • Viscous films formed at interface strongly affected the wear and aging behavior. • Diffusion of frictional heat led to post-crosslinking in the internal layer. [ABSTRACT FROM AUTHOR]

A novel apodization technique of writing a sampled Bragg grating is presented for the first time in the paper, which uses an amplitude mask with variable duty cycle and a phase mask. This technique only needs a one-process-exposure instead of two-process-exposure to write an apodized sampled Bragg grating. The numerical simulation has been implemented and the experimental results show that this technique is efficient in reducing the side lobes in the spectrum reflection and the group delay ripples. [Copyright &y& Elsevier]

In this paper, a new implementation of the double exposure method for fabricating apodized fiber Bragg gratings by controlling the parameters of rotation stage and the number of UV-shots is presented. As a result, the average refractive index is kept nearly constant along the Bragg grating, and various apodized fiber Bragg grating with high reflectivity and high side lobe suppression ratio have been fabricated in single-mode hydrogen-loaded photosensitive fiber . The achieved side-lobe suppression ratio is larger than 25 dB. [Copyright &y& Elsevier]

Properly designed sampling function of a sampled Bragg grating can produce an equivalent chirp profile within reflection bands with non-zero Fourier orders. This method has the advantage that various equivalent chirp profiles can be achieved while the phase mask used in the fabrication process needs not to have any chirp. The principle of this method is demonstrated by the fabrication of a sampled fiber Bragg grating with a linear equivalent chirp profile using a uniform-period phase mask. [Copyright &y& Elsevier]

This paper discusses the impairment of bandwidth cutoff and group delay jump effects to eye opening penalty of chirped sampled Bragg grating dispersion compensator at 10 and 40 Gb/s theoretically. Both analytical and numerical simulation results show that bandwidth cutoff effect is the main reason for deterioration of eye opening penalty, while group delay jump effect is negligible. Cascaded transmission simulations also show that bandwidth cutoff effect does not cause the penalty deterioration apparently when span number increases. [Copyright &y& Elsevier]

• As a natural antioxidant, NRCs improved the thermo-oxidative stability of NR. • NRCs promoted the formation of mono- and disulfide bonds during vulcanization. • More monosulfide bonds were formed during the aging of vulcanized SHANR. • SHANR showed high thermal/mechanical stability against aging. Non-rubber components (NRCs) in natural rubber (NR), including proteins, phospholipids, fatty acids, etc., determine to a large extent the structure and properties of NR. In this study, the effects of NRCs on the network structure and thermo-oxidative aging behavior of unvulcanized and vulcanized NR were investigated. NRCs were found to form physically crosslinked networks in the unvulcanized NR and acted as a natural antioxidant to scavenge free radicals, which contributed to improved thermo-oxidative stability of the unvulcanized NR. Swell analysis, chemical probe analysis (DPPH), and XPS results showed that the NRCs accelerated the vulcanization reaction and increased the crosslink density, and promoted the formation of more mono- and disulfide bonds during vulcanization. When aged at high temperatures, more monosulfide bonds were formed in the vulcanized rubber with high contents of NRCs by cleaving and rearranging the poly- and disulfide bonds. NRCs were also found to increase the activation energy of thermal degradation and led to the better mechanical stability of vulcanized NR against thermal oxidation. [ABSTRACT FROM AUTHOR]

A novel fiber grating structure is proposed for the purpose of dispersion compensation. This kind of grating can be produced with a large chirp parameter and period sampled distribution along the grating length. There are multiple channels in the wide bandwidth and each channel has totally different dispersion and bandwidth. The dispersion compensation effect of this special designed grating is verified through system simulation. [Copyright &y& Elsevier]

We have developed and demonstrated a novel technique to manufacture large bandwidth grating with a nearly arbitrary transmittivity profile. The technique is based upon scanning the large chirped phase mask and controlling of the reflective index modulation distribution along the grating length. [Copyright &y& Elsevier]

We propose a novel solution for linearly tunable polarization mode dispersion (PMD) compensation by sampled Bragg gratings fabricated with uniform-period phase masks. This all-fiber PMD compensation technique is cost-effective and flexible in designing the differential group delay (DGD) profile. Based on numerical simulations, the efficiency of this PMD compensator is assessed for the 10 Gb/s NRZ transmission system with large DGD. With this compensator, a significant improvement can be achieved in the eye pattern of the received signal. [Copyright &y& Elsevier]

• The quarter-wavelength-shifted DFB laser is firstly reported to generate optical chaos. • Two paths of complex optical chaotic signals with a bandwidth above 10 GHz are simultaneously generated using just one laser diode. • A parallel physical random number generator (Ph-RNG) with a bit rate of 1.04 Tbps/channel is realized. We propose and experimentally demonstrate a parallel physical random number generator (Ph-RNG) based on a single quarter-wavelength-shifted distributed feedback laser (QWS-DFB LD). Though simply connecting the two output ports of the QWS-DFB LD to form a cross-coupled perturbation, we simultaneously produce two paths of complex optical chaotic signals with a bandwidth above 10 GHz. Furthermore, a dual-channel Ph-RNG with a bit rate of order terabit per second (Tbps) is implemented by combining a multi-bit extraction method. Final results show that our generated physical random numbers can successfully pass standard benchmark tests for randomness. [ABSTRACT FROM AUTHOR]

Terrestrial oils and rock extracts from the Nanpu Sag (Huanghua Depression, Bohai Bay Basin, China) were characterized by negative-ion electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and gas chromatography mass spectrometry (GC-MS). Molecular composition of neutral nitrogen and acidic oxygen compounds, mainly by N 1 , O 1 , and O 2 species were investigated in the samples. Increases in relative abundance and molecular condensation degree of oxygen-containing compounds and a decrease in the carbon number range of N 1 species were observed with the changes of kerogen from Type I to III for both the source rock extracts and the relevant oils, which indicates the influence of source input and discrimination potential. We also observed an apparent increase in the condensation degree and a decrease in the carbon number of the N 1 , O 1 and N 1 O 1 species with increasing maturity. The carbon numbers and double bond equivalent (DBE) values of the N 1 and N 1 O 1 species in the extracts showed a positive relationship (an approximately linear distribution) during thermal evolution. These results indicate that thermal maturity has a crucial influence on the composition. The relative abundance ratios of N 1 and O 1 species with specific DBE values and carbon number ranges, C 16–20 /C 21–50 -DBE 12 -N 1 , C 20–24 /C 25–50 -DBE 15 -N 1 , C 11–15 /C 16–27 -DBE 4 -O 1 , DBE 12 /DBE 9 -N 1 , and DBE 8–9 /DBE 4 -O 1 are proposed as thermal maturity indicators for the evaluation of mature and post-mature source materials. A strong primary migration fractionation effect on the heteroatom compounds was also observed, implying that these compounds can be used as migration auxiliary proxies. [ABSTRACT FROM AUTHOR]

Abstract: The phase-shifted distributed feedback (DFB) semiconductor laser with linearly chirped grating based on reconstruction equivalent chirp (REC) technique is theoretically analyzed and experimentally demonstrated for the first time. The asymmetric property of the lasing spectrum is analyzed according to the normalized threshold gain, and the different spectra from each facet of the laser are compared. Due to the low cost and fabrication flexibility, REC technique provides a promising way for the future practical applications of DFB lasers with chirped gratings. [Copyright &y& Elsevier]

Passivity of carbon steel was examined in saturated Ca(OH) 2 solution with different alternating temperatures. The results showed that the Fe3+/Fe2+ and OH-/O2- ratios decreased, and donor density in the passive film increased with the amplitude of temperature alternation. Cracks were observed in the film when the sample experienced a higher amplitude of temperature change. Passive films on the samples in 20–50 °C and 20–60 °C alternating temperature solution were less stable than those of their counterparts in 40 °C and 50 °C solution, respectively. Furthermore, a model was proposed to explain the degradation of passive films under alternating temperature. • Passive film formed at 20–50 and 20–60 °C was less stable and protective than that formed at 40 and 50 °C, respectively. • Temperature change with the amplitude of 20 °C can't while 40 °C can cause cracks in the passive film on carbon steel. • Cracks caused by high-amplitude temperature change cannot be re-passivated in a short time. [ABSTRACT FROM AUTHOR]

Abstract: A simple fiber ring laser is used for sensing based on beat frequency demodulation. Because of the absence of a mode selecting device, the mode spacings between multi-longitudinal modes in the laser can be large. Therefore, the beat frequency signals with high frequency are generated, and the high sensitivities will be achieved. In the experiment, six different beat frequency signals are studied and compared in strain sensing. Their sensitivities are in good agreement with theoretical predictions. The signal-to-noise ratios, 3-dB bandwidths, maximum measureable strains, stabilities, and their measurement accuracies are also measured and discussed. The fiber ring laser sensor system proposed is robust and cost-effective. [Copyright &y& Elsevier]

Abstract: A λ/4 phase-shifted distributed feedback (DFB) semiconductor laser with a preformed chirped grating used to compensate the spatial hole burning (SHB) induced index change is proposed and analyzed. It shows that compared with the three phase shifted DFB laser which is known for its good performance to eliminate SHB, the proposed SHB compensated laser has better single longitudinal mode property, narrower spectral linewidth and better dynamic characteristics. [Copyright &y& Elsevier]