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In wireless rechargeable sensors (WRSNs), the system is vulnerable to be attacked by malware. Because of the distributed network structure of WRSNs, the malware attack has great influence on the security system of WRSNs. With the variability in malware, the problem of decryption and coding errors will lead to the malware mutating. In this paper, there are two problems to be solved, including the malware mutation and the charging delay in WRSNs. The malware mutation state and the low-energy state are introduced. Firstly, three different equilibrium solutions of the mutation model are given. Then, the local stability is proven by the characteristic equation, and the system will be stabilized at different equilibrium solutions when the base reproductive number is different. With the condition of charging delay, the bifurcation phenomenon is investigated by using the Hopf bifurcation theory. Furthermore, to improve the security of WRSNs and decrease the control cost, the Pontryagin's Maximum principle is applied to obtain an optimal control scheme under mutation and charging delay. Finally, the numerical simulation is applied by Matlab to confirm this model. The simulation results show that the mutation malware can be controlled when the delay is less than the maximum threshold. [ABSTRACT FROM AUTHOR]

Absorption tomography plays a crucial role in quantitatively imaging temperature and absolute concentration in combustion. However, there is scarce research on the tomography of OH radicals, which are significant for combustion diagnostics. This study presented a new tomography method to image OH radicals, termed ultraviolet broadband absorption tomography (UV-BAT). Three strategies were proposed to solve the nonlinear problem in UV-BAT tomography, namely all-spectra fitting, weak-absorption approximation, and multi-temperature approximation. The proposed UV-BAT method was applied for OH imaging in methane/air axisymmetric laminar Bunsen flames with different equivalence ratios (ϕ = 0.9, 1.0, and 1.1). The reconstructed OH distributions showed distinctive structures of Bunsen flames including premixed and diffusion flame areas. The accuracy of the UV-BAT method was validated by comparing tomography results with computational fluid dynamics (CFD) simulations using the USC-Mech II mechanism, demonstrating good agreement in two-dimensional (2D) temperature and OH concentration distributions. This novel method offers new opportunities for tomographic reconstruction of free radicals such as OH and temperature in small-scale flames. Novelty and significance This study demonstrated a novel tomography imaging method using ultraviolet broadband absorption spectroscopy to reconstruct temperature and radical concentration in combustion. This method possesses high sensitivity to free radicals and employs compact and inexpensive equipment, making it one of the most viable methods for realizing free radical absorption tomography. The 2D imaging of OH radicals using this method based on axisymmetric absorption tomography was accomplished for the first time. In conclusion, this study enriched the diagnostic methods of flame radicals based on absorption spectroscopy and provided new ideas for small-scale temperature tomography. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mid-infrared line strengths and line shape parameters in the CO 2 ν 3 band were measured behind reflected shock waves up to 2500 K. • Ar- and N 2 – broadening and shift coefficients were obtained up to J = 90. • Line strengths agree well with the HITEMP database at high temperatures. • The Double Power Law (DPL) model was used to fit line shape parameters at high temperatures. Line strengths and line shape parameters of Ar- and N 2 -perturbed CO 2 R-branch transitions (82 ≤ J ″ ≤ 90) in the ν 3 fundamental band were measured in a shock tube from 730 K to 2500 K and pressure below 1.13 atm using laser absorption spectroscopy (LAS). The retrieved absorption curves were fitted with the Voigt and the quadratic speed-dependent Voigt (qSDV) profiles to obtain the line strengths, broadening, and shift coefficients. Line strengths were compared to values in HITEMP, HITRAN2020, and Ames2021 databases, and the HITEMP shows the best agreement with the measured results. Ar- and N 2 -broadening and shift coefficients were regressed into the power law and the double power law form to study the temperature dependence of the targeted lines. The speed-dependence parameter a w was temperature-dependent. The J -dependence of the derived broadening and shift coefficients was discussed. The results of this work will aid the development of the absorption model in the far-wing region and the design of CO 2 LAS sensors for high-temperature measurement. [ABSTRACT FROM AUTHOR]

• Combined a shock tube with a laser absorption system for the combustion diagnostics for ammonia/large hydrocarbons. • The NH 3 , H 2 O, and NO time-histories were simultaneously measured during ammonia/n-heptane and ammonia/isooctane mixtures. • Detailed kinetics analyses were performed and the rate constants of key reactions were updated to improve model performances. Adding highly active fuels with ammonia is a compromising way to increase the mixture's reactivity. However, there are very few studies blending ammonia with large hydrocarbons, such as n-heptane and isooctane. In this study, the NH 3 , NO, and H 2 O time-histories were simultaneously measured during the oxidation of ammonia/n-heptane and ammonia/isooctane mixtures (equivalence ratio ϕ ∼ 1.2) in a shock tube. For the ammonia/n-heptane mixture, a reduced kinetics model, the Wang 2023 model, shows the best predictions in terms of the mixture reactivity and the H 2 O production but underpredicts the NO plateau. For the ammonia/isooctane mixture, the CRECK_TPRF_Alcohols_NOx (CRECK) model is the only available kinetics model containing ammonia and isooctane mechanisms. The CRECK model captures the H 2 O plateau but underpredicts the ammonia/isooctane mixture reactivity and the NO plateau. Detailed analyses are conducted based on the Wang 2023 and CRECK models. Rate-of-production (ROP) analyses reveal that: the consumption or formation pathways of the three species in the two models are basically the same but the magnitudes of the ROPs are quite different, especially for the NO formation; the reaction of ethylene or propylene with NH 2 radical in the Wang 2023 model also contributes significantly to the NH 3 consumption but they are not considered in the CRECK model. Sensitivity analyses show that: H + O 2 = O + OH is the most promoting reaction for both mixtures and models; however, several reactions show strong effects in one mixture while having little effect in another mixture, or even playing an opposite effect. After modifying or adding some key reactions, the Wang 2023 and CRECK models get significantly improved in predicting the species' time-history during the oxidation of the ammonia/n-heptane or ammonia/isooctane mixture. [ABSTRACT FROM AUTHOR]

In order to research kinetics properties of hydrogen-enriched n-butane mixtures, this study measured the ignition delay time of nC 4 H 10 /H 2 mixtures in shock tube tests and time-resolved CO 2 concentrations during combustion process by combining laser absorption diagnostics. The experimental data were compared with numerical predictions from three kinetic mechanisms, and the modified NUIG Mech shows improved performances in predicting ignition delay time and time-resolved CO 2 concentrations. Higher nC 4 H 10 :H 2 ratio led to lower reactivities because the main combustion happens after the oxidation of nC 4 H 10. Lean mixtures (ϕ = 0.5) ignites significantly faster than stoichiometric mixtures. It is possible to adjust ratios of nC 4 H 10 to H 2 in fuel mixture to fit the combustor design because of the varying combustion characteristics. The CO 2 formation occurs after complete oxidation of nC 4 H 10 with the primary sources being small molecules or radicals. Reaction path analyses show that nearly half of the CO 2 is formed through the reaction CO + OH = CO 2 + H. [ABSTRACT FROM AUTHOR]

The temperature and multi-species concentration distributions, including NH, OH, NO, and NH 3 , are of great importance to the research on ammonia/methane combustion mechanisms. However, there is scarce research simultaneously measuring these parameters in atmospheric-pressure ammonia/methane flames. In this work, we proposed a measurement method based on the ultraviolet broadband absorption spectroscopy (BAS) to realize the simultaneous measurement of temperature and multiple species concentrations for the first time (absolute concentrations for OH, NH, and NO, and relative concentrations for NH 3). Due to the strong absorption of the electronic transitions in the ultraviolet range, the proposed method offers low detection limits for concentration measurements. Taking NH radicals as an example, the detection limit is as low as 31 ppb at 1700 K. High sensitivity for temperature measurements is also achieved due to the multi-line spectra of OH broadband absorption. Moreover, a fitting strategy was proposed to separate the NO and NH 3 spectra near 225 nm, enabling a simultaneous determination of both species. We established an optical system based on the proposed BAS method with a spatial resolution of approximately 0.1 mm to perform spatially resolved measurements of temperature and multiple species on atmospheric ammonia/methane/air flames. The ammonia/methane flames were investigated at different equivalence ratios (0.9, 1.0, and 1.1) and different ammonia mole fractions in fuels (10%, 30%, and 50%). As investigated, NH and NH 3 concentrations increased linearly with increasing ammonia mole fractions, while OH and NO concentrations decreased in similar trends with increasing equivalence ratios. The experimentally measured temperature and multi-species concentrations were compared with computational fluid dynamics (CFD) simulations using the mechanism of the CRECK modeling group. Good agreements were achieved in absolute values, spatial profiles, and variations with equivalence ratios and ammonia mole fractions. • BAS was used to measure multiple species (NH, OH, NO, and NH 3) for the first time. • A low detection limit (SNR = 1) of 31 ppb was achieved for the trace NH radical. • OH BAS has high sensitivity to temperature due to the multi-line spectra. • NO and NH 3 can be simultaneously measured by separating their absorbances. • The experimentally measured distributions agreed well with CFD simulations. [ABSTRACT FROM AUTHOR]

In this paper, a novel framework of sparse kernel learning for support vector data description (SVDD) based anomaly detection is presented. By introducing 0-1 control variables to original features in the input space, sparse feature selection for anomaly detection is modeled as a mixed integer programming problem. Due to the prohibitively high computational complexity, it is relaxed into a quadratically constrained linear programming (QCLP) problem. The QCLP problem can then be practically solved by using an iterative optimization method, in which multiple subsets of features are iteratively found as opposed to a single subset. However, when a nonlinear kernel such as Gaussian radial basis function kernel, associated with an infinite-dimensional reproducing kernel Hilbert space (RKHS) is used in the QCLP-based iterative optimization, it is impractical to find optimal subsets of features due to a large number of possible combinations of the original features. To tackle this issue, a feature map called the empirical kernel map, which maps data points in the input space into a finite space called the empirical kernel feature space (EKFS), is used in the proposed work. The QCLP-based iterative optimization problem is solved in the EKFS instead of in the input space or the RKHS. This is possible because the geometrical properties of the EKFS and the corresponding RKHS remain the same. Now, an explicit nonlinear exploitation of the data in a finite EKFS is achievable, which results in optimal feature ranking. Comprehensive experimental results on three hyperspectral images and several machine learning datasets show that our proposed method can provide improved performance over the current state-of-the-art techniques. [ABSTRACT FROM PUBLISHER]

A small-sized meta-basic rock system is discovered in Qilongwuru Gully of Central Qiangtang's Shuanghu region and contains a meta-basalt and garnet-bearing plagioclase amphibolite. The zircon U/Pb age of this meta-basalt by SHRIMP analysis is 463.3±4.7 Ma, suggesting that this lava formed in the Middle Ordovician, and is consistent with that of the meta-basic rocks in the Taoxing Lake and Guoganjianian Mountain ophiolite found in the Qiangtang plate. As this lava system bears similar geochemistry to N-MORB, it might be a component of ophiolite that represents the trail of the extinction of the Proto-Tethys, suggesting that the formation of Proto-Tethys oceanic basin in the Longmu Co-Shuanghu suture zone could date as far back as to the Middle Ordovician. Isotopic geochemical analysis indicates that the magma source area consists of both depleted mantle (DM) and enriched mantle (EMII) end members and bears Dupal anomaly, similar to that of the Paleo-Tethys in the Neo-Tethys represented by the Yarlung-Tsangpo suture zone, the Paleo-Tethys represented by the Changning-Menglian suture zone, and the Paleo-Tethys in Sanjiang region. This suggests that they have inherited the attribute of the Proto-Tethys mantle domain, and the Longmu Co-Shuanghu suture zone may be a representative of the northern boundary of Gondwana. [ABSTRACT FROM AUTHOR]

Abstract: The NF-κB is best known for its role in inflammation. Here we show that constitutive NF-κB activity in cancer cells promotes the biosynthesis of redox scavenger glutathione (GSH), which in turn confers resistance to oxidative stress. Inhibition of NF-κB significantly decreases GSH in several lines of human leukemia and prostate cancer cells possessing high or moderate NF-κB activities. Concomitantly, NF-κB inhibition by pharmacological and molecular means sensitizes “NF-κB positive” cancer cells to chemically-induced oxidative stress and death. We propose that inhibition of NF-κB can reduce intracellular GSH in “NF-κB-positive” cancers thereby improving the efficacy of oxidative stress-based anti-cancer therapy. [ABSTRACT FROM AUTHOR]

Abstract: Plasma in the air is successfully induced by a free-oscillated Nd:YAG laser pulse with a peak power of 102–3 W. The initial free electrons for the cascade breakdown process are from the ablated particles from the surface of a heated coal target, likewise induced by the focused laser beam. The laser field compensates the energy loss of the plasma when the corresponding temperature and the images are investigated by fitting the experimental spectra of B 2∑+ → X 2∑+ band of CN radicals in the plasma with the simulated spectra and a 4-frame CCD camera. The electron density is estimated using a simplified Kramer formula. As this interaction occurs in a gas mixture of hydrogen and oxygen, the formation and development of the plasma are weakened or restrained due to the chaining branch reaction in which the OH radicals are accumulated and the laser energy is consumed. Moreover, this laser ignition will initiate the combustion or explosion process of combustible gas and the minimum ignition energy is measured at different initial pressures. The differences in the experimental results compared to those induced by a nanosecond Q-switched laser pulse with a peak power of 106–8 W are also discussed. [Copyright &y& Elsevier]

Objectives: Tracheobronchial Talaromyces marneffei (T. marneffei) infections among HIV-infected patients are rare. To improve understanding, we analyzed the clinical features, immune mechanisms, treatment, and prognosis of these patients. Methods: We collected clinical information from HIV-positive patients with talaromycosis admitted to the Fourth People's Hospital of Nanning from January 2015 to June 2022. Patients who presented with culture and/or histopathological proof of tracheobronchial T. marneffei infection were included. Results: A total of 108 patients with respiratory infections who underwent bronchoscopy were enrolled. Seven patients with tracheobronchial T. marneffei infection, all of whom were men with a median age of 48 years (range 39–50 years), were analyzed. Cough, sputum, fever, and weight loss were the most common symptoms. The total white blood cell count was normal or decreased, and all lymphocyte counts were decreased. All patients had reduced CD4+ T-cell counts, with values less than 50 cells/µL. The chest CT imaging signs included patchy signals or large areas of exudation, bronchial stenosis and occlusion. This was different from the lack of bronchial involvement. Endoscopically, the trachea and bronchial mucosa showed congestion, edema, surface attachment, nodules, lumen stenosis, obstruction, etc. T. marneffei spores were found via bronchial mucosal pathology in all 7 patients. Five patients were initially treated with intravenous infusion of amphotericin B for 2 weeks, followed by oral itraconazole capsules (200 mg) twice daily, and two patients were initially treated with itraconazole. Six patients were remission, and 1 died. Conclusions: The clinical features of trachea invasion and nontracheal invasion are not unique, but chest CT reveals manifestations such as masses, solid shadows, and bronchial stenosis/obstruction. Bronchoscopy should be performed if possible, and the presence or absence of trachea T. marneffei infection should be confirmed. Antiviral therapy combined with antifungal therapy can improve patient prognosis. [ABSTRACT FROM AUTHOR]

Virus spreading problems in wireless rechargeable sensor networks (WSNs) are becoming a hot topic, and the problem has been studied and discussed in recent years. Many epidemic spreading models have been introduced for revealing how a virus spreads and how a virus is suppressed. However, most of them assumed the sensors are not rechargeable sensors. In addition, most of existing works do not consider virus mutation problems. This paper proposes a novel epidemic model, including susceptible, infected, variant, low-energy and dead states, which considers the rechargeable sensors and the virus mutation factor. The stability of the proposed model is first analyzed by adopting the characteristic equation and constructing Lyapunov functions methods. Then, an optimal control problem is formulated to control the virus spread and decrease the cost of the networks by applying Pontryagin's maximum principle. Finally, all of the theoretical results are confirmed by numerical simulation. [ABSTRACT FROM AUTHOR]

• Gas temperature and OH mole fraction in CH4/air premixed flat flames were simultaneously measured by UV BAS. • The measured results from BAS were compared with those from TDLAS and CFD, and good agreements were obtained. • Compared with TDLAS, BAS has the distinct advantages of lower OH detection limits and higher temperature sensitivity. • The advantages of BAS was analyzed theoretically and shown in experiments. We report temperature and hydroxyl (OH) concentration measurements in methane/air premixed flat flames based on ultraviolet (UV) broadband absorption spectroscopy (BAS) of the OH electronic transitions ( X 2 Π - A 2 Σ + ). The temperature and OH mole fraction distributions were obtained at different heights above the burner for various equivalence ratios (ϕ = 0.6, 0.7, 0.8, 0.93, and 1.06). The results agreed well with computational fluid dynamics (CFD) simulations using the AramcoMech 1.3 skeletal mechanism, which verifies the BAS measurement accuracy. For stable flames (ϕ = 0.6, 0.7, and 0.8), the root-mean-square differences above the flat flames were all less than 16 K for the temperature and 150 ppm for the OH mole fraction. The BAS results also agreed with tunable diode laser absorption spectroscopy (TDLAS) measurements with a root-mean-square temperature difference of 31.5 K. Experimental and theoretical analysis demonstrates that the UV BAS OH detection limit is more than two orders of magnitude lower than that for infrared (IR) TDLAS, and the OH BAS temperature sensitivity is much higher than that for most line pairs in TDLAS measurements. These advantages make the UV BAS method an accurate method for combustion diagnostics, with more accurate temperature and OH concentration than IR TDLAS. [ABSTRACT FROM AUTHOR]

• The ignition delay times and time-resolved CO 2 concentration during combustion of iC 4 H 10 /H 2 mixtures were measured. • The measured data were compared with predictions from three mechanisms. • Sensitivity analyses, butane oxidation and CO 2 formation paths were performed. • A comparison between nC 4 H 10 /H 2 mixtures and iC 4 H 10 /H 2 mixtures was presented. This study measured the ignition delay times of iC 4 H 10 /H 2 mixtures in shock-tube experiments at 1310–1450 K and time-resolved CO 2 concentrations by combining tunable diode laser absorption spectroscopy. The aim was to determine the performance of using isobutane as additive in changing hydrogen reactivity. The measured data were compared with predictions based on the three mechanism, namely, AramcoMech 2.0, Hychem model and CRECK mechanism. Results showed that data obtained using AramcoMech 2.0 best agreed with the measured data. Formation-path analyses demonstrated that the three mechanism provided different isobutane oxidation and CO 2 formation paths at the selected time point. This study did further comparisons between n-butane and isobutane as additives to check the performance of butane and its isomer in changing hydrogen-enriched-fuel reactivity. Adding isobutane was found to prolong the ignition delay times of hydrogen-enriched mixtures more evidently than adding the same amount of n-butane. Isobutane showed similar initial oxidation as n-butane but had fewer channels through direct unimolecular decomposition. CO 2 formation-path analyses based on AramcoMech 2.0 demonstrated that CO + OH = CO 2 + H occupies a higher proportion in CO 2 formation channels during n-butane combustion than during isobutane combustion at the selected time point. [ABSTRACT FROM AUTHOR]

• WM-DAS method was adopted to enhance the noise rejection and improve the measurement accuracy of the spectroscopic parameters with high signal-noise ratio. • An improved experimental strategy was used in our experiments, including a new designed heated static cell to achieve better gas impermeability and temperature uniformity, and a reference light path to eliminate the effect of ambient gas and inherent fluctuation of laser intensity. • The spectroscopic parameters of 8 H 2 O transitions near 1.39 μm were measured using various lineshape models to validate the accuracy of WM-DAS method and the improved experimental strategy. The wavelength modulation-direct absorption spectroscopy (WM-DAS) was used to measure the spectroscopic parameters for 8 H 2 O absorption transitions near 1.39 μm at 300–900 K. A reference light path was introduced to eliminate the effect of ambient gas and inherent fluctuation of laser intensity. Experimental results at high temperatures for the transition at 7185.597 cm−1 showed that the WM-DAS enhanced noise rejection by extracting the characteristic frequencies of modulated laser intensity. The SNR was enhanced to 1800 for the peak absorbance of 20% and remained 380 around the peak absorbance of only 0.5% by using this method, showing its huge potential in situ gas sensing in harsh engineering fields. The Voigt, Rautian, Galatry and quadratic speed-dependent Voigt profiles were used to recover the absorbance and determine the best-fit spectroscopic parameters and their temperature dependence. The measured N 2 -broadening coefficients compare well with the available values listed in the HITRAN/HITEMP database. The Dicke narrowing and speed-dependent coefficients were also determined with analyses of the uncertainties in these measured parameters. [ABSTRACT FROM AUTHOR]

The absorbance is of great importance in the tunable diode laser absorption spectroscopy (TDLAS) as it contains information of both gas properties and spectroscopic parameters. A novel, calibration-free wavelength modulation-direct absorption spectroscopy (WM-DAS) is proposed and experimentally verified in this two-part paper. This method combines the capability of absorbance measurement from DAS and the advantages of enhanced noise rejection and high sensitivity from WMS. In this Part I, we focus on the full theoretical basis and procedures of this method from the following three aspects: the high-accuracy characterizations of laser frequency and intensity, noise rejection ability by extracting the characteristic spectra through the fast Fourier transform (FFT) of the light intensity, and the simultaneous fitting strategy for both baseline and absorbance. The preliminary validation experiment of CO transition at 4300.6999 cm−1 in a static gas cell shows the high accuracy of the proposed method. [ABSTRACT FROM AUTHOR]

Following the theoretical work in Part I, in this experimental study, the robustness, temporal resolution, and the narrow scan performance of the proposed wavelength modulation-direct absorption spectroscopy (WM-DAS) method are experimentally validated in a high-temperature tube furnace. The electromagnetic and other random-frequency noises can be effectively eliminated by extracting the characteristic spectra of the light intensity. The performance of WM-DAS with modulation frequencies from 0.1 to 100 kHz and scan indexes from 3.3 to 11.1 are also investigated at atmospheric pressure. The proposed method produces accurate line profile and high SNR over 500 consistently even with a weak absorption. As for real applications, the spectral line parameters of CO at 4300.6999 cm−1 including the collisional broadening, Dicke narrowing, and their dependence on temperature are measured. Furthermore, the high-speed measurement (1 ms) of the temperature and CO concentration of a McKenna flat flame are demonstrated. [ABSTRACT FROM AUTHOR]

The linestrengths and the self- and N 2 - broadening coefficients for 6 absorption transitions of C 2 H 4 located at v 5+ v 9 near 1.625 μm were measured using wavelength modulation direct absorption spectroscopy (WM-DAS) at 300–700 K. The Rautian and Voigt profiles were used to recover the absorbance and calculate the best-fit spectroscopic parameters and their temperature dependence. The transitions 6140.060 and 6140.405 cm−1 with less overlap between neighboring spectral lines were recommended to be used to measure C 2 H 4 concentrations and temperatures. The C 2 H 4 concentrations at 20 kPa and 1 atm were measured using the measured linestrength of the C 2 H 4 transitions. The results show good agreement within 6.7% between the measured concentrations and the actual concentrations (0.5% ˜ 100%) at 20 kPa. However, they only compare well within 5.3% for concentrations less than 20% at atmospheric pressure due to the severe overlap among neighboring spectral lines. [ABSTRACT FROM AUTHOR]

Highlights • Linestrengths and temperature-dependent lineshape self-parameters were measured for 8 CO 2 transitions near 1.43 µm from 300 to 1000 K. • Voigt, Rautian, Galatry and speed-dependent Voigt profiles are used to recover the absorbance and obtain self-spectroscopic parameters for CO 2. • The self-Dicke narrowing coefficients and self-speed-dependent coefficients were measured to account for the Dicke narrowing and speed-dependent effects in pure CO 2. • The 8 transitions exhibited linestrengths and self-broadening and narrowing coefficients that decreased with increasing temperature. Abstract Linestrengths, self-broadening and narrowing coefficients for 8 absorption transitions of CO 2 near 1.43 µm were measured using the wavelength modulation direct absorption spectroscopy (WM-DAS) at 300–1000 K and 5–20 kPa. The SNR was enhanced to 1500 for the peak absorbance around 5% at room temperature and remains at 550 for the peak absorbance around 1% at high temperatures by use of the WM-DAS method. The Voigt, Rautian, Galatry and quadratic speed-dependent Voigt profiles were used to recover the absorbance and retrieve the best-fit spectroscopic parameters and their temperature dependence. The quadratic speed-dependent Voigt profile was found to give the best combination of accuracy and robust lineshape parameters. The measured linestrengths and self-broadening coefficients compare well with the available values listed in the HITRAN/HITEMP database. The self-narrowing coefficients were also determined for GP, RP and qSDVP with analyses of the uncertainties in these spectroscopic parameters. [ABSTRACT FROM AUTHOR]

• The thermal decomposition of fire-extinguishing agent CF 3 I in high-temperature oxidizing environments was studied by experimental and theoretical methods. • The effects of initial concentration, temperature, and residence time on the decomposition rate were investigated. • The kinetics of thermal decomposition was calculated using the Arrhenius equation in which activation energy E a is 15.18 kJ/mol and pre-exponential factor (A) is 13.87s−1. • The reaction of CF 3 I in an oxidizing environment at high temperatures is with singlet oxygen. • O 2 participates in the thermal decomposition reaction and promotes the decomposition of CF 3 I. CF 3 I, as a novel "Halon" replacement fire-extinguishing agent, has the characteristics of low fire-extinguishing concentration, high efficiency, and safety. However, there are still some gaps in its thermal decomposition studies when it is released into the high-temperature fire, so the thermal decomposition of CF 3 I in oxidizing environments was studied to simulate its diffusive decomposition. The decomposition of CF 3 I was demonstrated to be accelerated by O 2 through experiments in the temperature range of 100°C-800°C in air and N 2 atmosphere. The effects of initial concentration, temperature, and residence time on the decomposition rate of CF 3 I and decomposition characteristics were investigated by tube furnace simulation. The kinetics of thermal decomposition was calculated using the Arrhenius equation in which activation energy E a is 15.18 kJ/mol and pre-exponential factor (A) is 13.87s−1. Additionally, the thermal decomposition products were examined by GC-MS and FTIR. The experimental results showed that the pyrolysis gas products were mainly CF 4 , C 2 F 6 , and CF 2 O. Using quantum chemistry and density flooding theory (DFT) calculations, it was concluded that the main decomposition pathway was the reaction of CF 3 I with singlet oxygen. The reaction pathway of the thermal decomposition of CF 3 I under a high-temperature fire oxidation environment was proposed based on the products. [Display omitted] [ABSTRACT FROM AUTHOR]

The article presents chemical equations for the article "Palladium-Catalyzed Suzuki Cross-Coupling of Arylhydrazines via C?N Bond Cleavage" by Z. Peng and others, published in the periodical "Journal of Organic Chemistry" in 2014.

Emissions from mobile sources and stationary sources contribute to atmospheric pollution in China, and its components, which include ultrafine particles (UFPs), volatile organic compounds (VOCs), and other reactive gases, such as NH 3 and NO x , are the most harmful to human health. China has released various regulations and standards to address pollution from mobile and stationary sources. Thus, it is urgent to develop online monitoring technology for atmospheric pollution source emissions. This study provides an overview of the main progress in mobile and stationary source monitoring technology in China and describes the comprehensive application of some typical instruments in vital areas in recent years. These instruments have been applied to monitor emissions from motor vehicles, ships, airports, the chemical industry, and electric power generation. Not only has the level of atmospheric environment monitoring technology and equipment been improving, but relevant regulations and standards have also been constantly updated. Meanwhile, the developed instruments can provide scientific assistance for the successful implementation of regulations. According to the potential problem areas in atmospheric pollution in China, some research hotspots and future trends of atmospheric online monitoring technology are summarized. Furthermore, more advanced atmospheric online monitoring technology will contribute to a comprehensive understanding of atmospheric pollution and improve environmental monitoring capacity. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: An intense orange-reddish-emitting phosphor, Eu2+ doped Ba2LiB5O10 was prepared by solid-state reactions. The excitation spectrum showed a broad band from 250nm to 400nm with an intense peak at 322nm. Under the excitation of 322nm, the emission band showed one large broad band peaking at about 590nm with full width at half maximum of 128nm, which corresponds to the 4f 65d 1→4f 7 transition of Eu2+. The critical quenching concentration of Eu2+ in Ba2LiB5O10:Eu2+ phosphor was about 3mol%. The corresponding concentration quenching mechanism was verified to be a dipole–dipole interaction. The value of the critical transfer distance was calculated to be about 19Å. The CIE coordinate (x, y) did not change from the value (0.54, 0.35) observed for 3mol% of Eu2+ when Eu2+ concentration was changed. [Copyright &y& Elsevier]

An optical sensor was developed for simultaneous detection of sulfur dioxide (SO2) and sulfur trioxide (SO3) at elevated temperatures using a quantum cascade laser (QCL) spectrometer. The SO2/SO3 concentrations and the SO2 conversions were measured during the heterogeneous catalytic reaction with S-101 intermediate-temperature vanadium catalysts at pressures of 3–20 kPa and temperatures of 550–1000 K. The SO2 spectra in the ν3 band and the SO3 spectra in the ν3 + ν4 band near 7.16 µm at elevated temperatures were well resolved in the strongly overlapping spectra by measuring the SO2 and SO3 high-temperature individual absorption spectra that were extended from room-temperature spectra in the HITRAN database. A SO2/SO3 separation unit was designed to extract and measure the remaining SO2 after conversion at room temperature, with the results comparing well with the optically measured concentrations in the high-temperature catalytic reactions. The system was then used to investigate the pressure and temperature dependencies of the heterogeneous conversions of SO2. SO3 was first detected at temperatures higher than 590 K with the SO2 conversion increasing to 92% at 797 K and then decreasing to less than 3% at 1014 K. The measured conversions show a logarithmic growth with increasing pressures at each temperature. The difference between the measured heterogeneous conversion and the theoretical conversion calculated using a thermodynamic model was also analyzed. [ABSTRACT FROM AUTHOR]

• Combined a shock tube with a laser absorption system for the combustion diagnostics. • Temperature, CO, CO 2 , H 2 O, NH 3 , and NO time-histories were simultaneously measured during ammonia/oxygenated hydrocarbons. • Kinetics models are detailly analyzed and improved by updating the rate constants of some reactions. Blending ammonia with highly active fuels (hydrogen, hydrocarbons, oxygenated hydrocarbons, etc.) has been identified as an efficient way to improve the mixture's reactivity. In this study, the temperature, CO, CO 2 , H 2 O, NH 3 , and NO time-histories were measured simultaneously during the oxidation of ammonia/ethanol and ammonia/diethyl ether (DEE) blends (equivalence ratio ϕ ∼ 1.2) using mid-infrared laser absorption spectroscopy behind reflected shock waves. Various models (ten for ammonia/ethanol and three for ammonia/DEE) were selected to perform the simulation and compared with the measurements. The predictions are very different for both mixtures, among which the CRECK model was selected to perform discussion and kinetics analyses for the ammonia/ethanol mixture and the Shrestha 2022 model was selected for the ammonia/DEE mixture. The CRECK model performs well in predicting the temperature rise/plateau, H 2 O formation rate/plateau, CO consumption rate/plateau, and CO 2 formation rate. However, it underpredicts the CO formation rate and slightly overpredicts the CO 2 plateau and NH 3 consumption rate; for the NO time-history, the CRECK model well captures the rapid NO formation but underpredicts the near-equilibrium NO concentration and gives an unnormal initial NO production. The Shrestha 2022 model accurately predicts the plateaus of temperature and H 2 O, but significantly underpredicts the reactivity of the ammonia/DEE mixture and overpredicts the near-equilibrium NO concentration. According to the kinetics analyses, key reactions affecting the species' time-histories were selected. Fourteen reactions in the CRECK model and eight reactions in the Shrestha 2022 model were updated by the reported data or estimations to improve the predictions. However, discrepancies still exist, which are mainly located in the CO formation and NH 3 consumption rates. Further effort should mainly focus on these two aspects, as well as the interactions between oxygenated hydrocarbons and ammonia at high temperatures. [ABSTRACT FROM AUTHOR]

The Phapon gold deposit, located in northern Laos, is a unique large-scale gold deposit in Luang Prabang-Loei metallogenic belt. It is hosted in the Lower Permian limestone and controlled by a NE-trending ductile-brittle fault system. There are three types of primary ore including auriferous calcite vein type, disseminated type, and breccia type, and the first two are important in the Phapon gold deposit. Based on fluid inclusion petrography and microthermometry, three types of primary fluid inclusions including type 1 liquid-rich aqueous, type 2 vapor-rich aqueous and type 3 daughter mineral-bearing aqueous were identified in hydrothermal calcite grains. The ore-forming fluids are normally homogeneous, as indicated by the widespread type 1 inclusions with identical composition. The coexistence of type 1 and type 2 inclusions, showing similar final homogenization temperature but different compositions, indicate that fluid immiscibility did locally take place in both two types of ores. The results of microthermometry and H-O isotopes geochemistry indicate that there are little differences on ore-fluid geochemistry between the auriferous calcite vein-type and disseminated type ores. The oreforming fluids are characterized by medium-low temperatures (157—268 °C) and low salinity (1.6 wt.%-9.9 wt.% NaCl eq.). It is likely to have a metamorphic-dominant mixed source, which could be associated with dehydration and decarbonisation of Lower Permian limestone and Middle-Upper Triassic sandstones during the dynamic metamorphism. The fluid-wallrock interaction played a major role, and the locally occurred fluid-immiscible processes played a subordinate role in gold precipitation. Combined with the regional and ore deposit geology, and ore-fluid geochemistry, we suggest that the Phapon gold deposit is best considered to be a member of the epizonal orogenic deposit class. [ABSTRACT FROM AUTHOR]

An integrated study of zircon U-Pb geochronology and petrochemistry, together with zircon Lu-Hf isotopes, has been carried out on the basaltic-andesitic tuff and volcanic breccia from the Nam Hang Formation and andesitic tuff from the Muang-Nan Formation in the Xaignabouli area, which had been mapped as the Permian-Early Triassic on the 1 : 1 000 000 geological map or Late Carboniferous on the 1 : 200 000 geological maps. Zircon U-Pb dating of three samples yielded weighted mean ages of 235±2.6, 232±1.4 and 278±2.8 Ma, respectively, suggesting a Late Triassic origin for the Nam Hang Formation and an Early Permian origin for the Muang-Nan Formation. Geochemically, they are characterized by depletions in HFSEs (e.g., Nb, Ta, Ti) and high LILE/HFSE ratios, and they have positive zircon εHf(t) values of 8.7-15.9, which exhibits the continental arc volcanic affinity and partial melting of subducting oceanic slab in the magma source. Combined with spatial occurrence of the volcanic rock and existing geochronological and geochemical data, we suggest that the Xaignabouli-Luang Prabang volcanic belt can be linked to the Loei-Phetchabun belt. The Permian-Triassic volcanic rocks in this belt might be a product of the Nan back-arc basin eastward subduction. [ABSTRACT FROM AUTHOR]

Ammonia (NH 3) is a promising hydrogen carrier and carbon-free fuel, which can be synthesized using renewable energy and has attracted increasing attention from both academic and industrial communities. This study selected six absorption lines and developed a laser absorption diagnostics system that can simultaneously measure the temperature, CO, CO 2 , H 2 O, NH 3 , and NO time-histories during the oxidation of CH 4 /H 2 /NH 3 and C 2 H 4 /NH 3 mixtures (equivalence ratio ϕ ≈ 1.2) behind reflected shock waves. Since the fuels were highly diluted to reduce the nonideal effects and heat release behind reflected shock waves, the maximum NO mole fraction was only ∼0.2% and led to a small absorption (< 2.0%). Therefore. the wavelength modulation spectroscopy (WMS-2 f /1 f) was used for the NO time-history measurements while the other species were measured using fixed-wavelength absorption spectroscopy. A total of thirteen kinetics models were used to interpret the measurements. The main differences between the model predictions and measured data lie in two aspects: the mixture reactivities and the NO production. Generally speaking, for both CH 4 /H 2 /NH 3 and C 2 H 4 /NH 3 mixtures, the Glarborg model performs the best in predicting the temperature and species time-histories but the differences still exist. The high-quality experimental data support further analyses and improvements. Detailed kinetics analyses based on the Glarborg 2018 model were performed. It indicates that H + O 2 = O + OH is the most sensitive and promoting reaction for both mixtures, followed by the H-abstraction reactions of H 2 and C 2 H 4. Conversely, the H-abstraction reactions of CH 4 and NH 3 impede oxidation due to competition with promoting reactions for reactants (H, OH, or O). Moreover, subsequent reactions involving the produced CH 3 or C 2 H 3 radicals also have significant effects on oxidation. The reactions affecting the NO plateau were also selected as the basis to optimize the predicted NO plateau. Although updating the rate constants of some key reactions improved model performance for both mixtures, discrepancies still exist, particularly for the C 2 H 4 /NH 3 mixture. [ABSTRACT FROM AUTHOR]

Ratios of the 2nd and 1st harmonics at the line center are very sensitive to absorbance, but not to line profiles when the modulation index is set to 0.94. Based on this characteristic, we proposed a method which uses the 1st and 2nd harmonics to measure the absolute absorbance, and then obtain gas pressure and concentration. Some transitions of CO and HO molecules near 6980 cm are selected to verify this method. The satisfactory agreement between measurement results and theoretical values validates the proposed method. [ABSTRACT FROM AUTHOR]

Ammonia (NH 3) is a promising carbon-free fuel for carbon neutrality that has recently received increasing attention. However, NO x emissions are one of the main problems for NH 3 or NH 3 -blended combustion. This study used nitromethane (CH 3 NO 2) as a nitric oxide precursor to study NH 3 /NO interactions at high temperatures. The temperature, CO, CO 2 , NO, and NH 3 time-histories were measured simultaneously during the pyrolysis and oxidation (equivalence ratios ϕ = 2.0 and 1.0) of CH 3 NO 2 and CH 3 NO 2 /NH 3 mixtures behind reflected shock waves using mid-infrared laser absorption spectroscopy to analyze the NH 3 /NO interactions. The measurements were used to validate and evaluate seven kinetic models which gave very different predictions for the different mixtures, among which the Glarborg et al. (2018) and Shang et al. (2020) models agreed best with the temperature, NO, and NH 3 measurements. The measured CO and CO 2 time-histories are shown in the Supplementary Material. Both mechanisms accurately capture the temperature plateau while the main difference is the temperature increase during oxidation. The NO formation rate and plateau concentrations during CH 3 NO 2 pyrolysis are better predicted by the Shang model than by the Glarborg model. Both mechanisms capture the NO formation rate for CH 3 NO 2 oxidation with ϕ = 2.0 but underestimate it for ϕ = 1.0. With NH 3 , the Glarborg model better predicts the NO removal during CH 3 NO 2 /NH 3 pyrolysis. However, both mechanisms underestimate the NO formation rate and maximum but overestimate the NO removal rate and NH 3 consumption for CH 3 NO 2 /NH 3 oxidation. Rate-of-production and sensitivity analyses show that: for the NO formation, CH 3 + NO 2 = CH 3 O + NO and NO 2 + H = NO + OH are the primary pathways and CH 3 NO 2 (+ M) = CH 3 + NO 2 (+ M) is the most sensitive reaction. NH 3 + OH = NH 2 + H 2 O contributes the most to the NH 3 consumption during CH 3 NO 2 /NH 3 pyrolysis, while NH 3 + H = NH 2 + H 2 and NH 3 + O = NH 2 + OH are increasingly important at oxidation condition. NH 2 + NO = N 2 + H 2 O and NH 2 + NO = NNH + OH are the most important reactions for the NO reduction with NH 3 existing. The rate constants of some key reactions were revised to improve the predictions. [ABSTRACT FROM AUTHOR]

As a carbon-free fuel, NH 3 has been considered as a potential and promising alternative energy carrier in the future transportation system. This study simultaneously measured the temperature and NH 3 -concentration time histories during the oxidation processes of the shock-heated NH 3 /H 2 mixtures by combining laser absorption techniques. The v " = 0, P8 and v " = 1, R21 lines in the fundamental vibrational band of CO were selected for temperature time-history measurements. Nine transition lines in the v 2 fundamental vibrational band of NH 3 near 8.91 µm were selected for NH 3 -concentration time-history measurements. The temperature- and pressure-dependent NH 3 absorption cross-section highly diluted in argon was measured at 1000–2200 K and 0.8–3.9 bar, respectively. The time-dependent temperature and NH 3 concentration were then measured and compared with the predictions based on four mechanisms (Mathieu & Petersen, 2015; Glarborg et al., 2018; Wang et al., 2020; Shrestha et al., 2021). The four mechanisms were substantially slow in predicting the NH 3 -concentration time histories for the stoichiometric NH 3 /H 2 mixtures. The Glarborg et al. mechanism and the Shrestha et al. mechanism showed very good agreements with the experiments for the fuel-rich NH 3 /H 2 mixtures, especially in predicting the NH 3 -concentration time-history profiles in the burnout state. Comprehensive kinetics analyses illustrated that the NH 3 addition evidently changed the mixture reactivity and formation and consumption processes of H and OH radicals. This study updated the rate coefficients of NH 3 + OH = NH 2 + H 2 O in the Glarborg et al. mechanism and the modified mechanism showed improved performances in predicting the NH 3 -concentration profiles. [ABSTRACT FROM AUTHOR]

The temperature, CO, and CO 2 time-histories for the fuel-rich (equivalence ratio ϕ = 1.2 and 2.0) oxidation of n-heptane/diethyl ether/O 2 /argon mixtures were measured simultaneously in a shock tube using laser absorption spectroscopy. Two transition lines (v " = 0, P8, 4.73 μm and v " = 1, R21, 4.56 μm) in the CO fundamental band were selected to simultaneously measure the temperature and CO time-histories. One transition line in the CO 2 fundamental band (v 3 "= 0, R88, 4.18 μm) was used for the CO 2 time-history measurements, with its absorption cross-section measured at 1240 – 2600 K and 0.7 – 3.8 bar. A kinetic model was then developed that combined the NUI Galway 1.1 mechanism and the DEE sub-mechanism (Sakai et al. 2017). All the measured data were compared with predictions based on the proposed mechanism and the Zeng et al. (2017) mechanism. Both mechanisms accurately predicted the near-equilibrium/plateau temperatures for ϕ = 2.0 and CO for ϕ = 1.2. However, for ϕ = 1.2, both mechanisms slightly overpredict the near-equilibrium temperature and CO 2. For ϕ = 2.0, the presented mechanism better predicts the CO plateau concentrations while the Zeng et al. (2017) mechanisms are better in predicting CO 2 plateau concentrations. The predictions were less accurate for the temperature rise and CO/CO 2 -evolution processes. The predictions were also less accurate for specific equivalence ratios and blending ratios of n-heptane and diethyl ether. Rate-of-production analyses showed that HCO + M = H + CO + M is the primary pathway for producing CO and CO + OH = CO 2 + H is the primary pathway for producing CO 2 for the conditions in this manuscript. Sensitivity analyses show that the most sensitive reaction is H + O 2 = OH + O , with some reactions related to AXC 3 H 5 and CH 3 CHO also influencing the CO and CO 2 time-histories. Modifying the rate constants of the specific reactions reduces the differences between the predicted and measured results, but discrepancies still exist and the mechanisms need to be further improved. [ABSTRACT FROM AUTHOR]

A novel methodology for the creating C-P bond via the oxidative coupling of a wide range of arylboronic acids with various H-phosphine oxides in the presence of palladium catalyst under dry air as the green oxidant is described. [ABSTRACT FROM AUTHOR]

Abstract: The novel white emitting phosphors Ba3Y1−x (PO4)3:xDy3+ have been synthesized by conventional solid-state reaction. The structure of the compound was confirmed by the XRD technique. Under the excitation of 348nm, the peaks of the emission spectra of Dy3+ ions are located at 486nm (blue), 575nm (yellow) and 668nm (red) corresponding to the magnetic dipole 4F9/2–6H15/2 transition, the electric dipole 4F9/2–6H13/2 transition and 4F9/2–6H11/2 transition. Concentration quenching occurs when the Dy3+ concentration is beyond 8mol%. The critical transfer distance is calculated to be about 18.98Å and the major concentration self-quenching mechanism of Ba3Y(PO4)3:Dy3+ is the dipole–dipole interaction. The chromaticity coordinates (x=0.3475, y=0.3815) of the as-obtained Ba3Y(PO4)3:Dy3+ phosphors are very close to the “ideal white” (x=0.33, y=0.33). The research results indicate that the Ba3Y1−x (PO4)3:xDy3+ phosphor may be a promising single-component phosphor in the field of solid state lighting in lamp industry. [Copyright &y& Elsevier]

A novel and efficient Ni-catalyzed coupling of a wide range of arylboronic acids with H-phosphites, H-phosphinate esters, and H-phosphine oxides has been developed, providing a general and powerful tool for the synthesis of various aryl-phosphorus compounds, especially for valuable triarylphosphine oxides, in good to excellent yield. This protocol is the first Ni-catalyzed C–P bond-forming reaction between arylboronic acids and P(O)H compounds. [ABSTRACT FROM AUTHOR]

N-phosphorylation labeling was utilized to analyze the low molecular weight compounds by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). A wide range of natural amino acids and short peptides was successfully analyzed by MALDI-TOF MS without matrix background interferences. The N-phosphorylation labeling reaction was carried out easily within 30 min in a one-pot reaction under mild reaction conditions. The phosphoryl derivatization reaction is a global labeling approach with high selectivity and high specificity with targeting only on the N-terminal and ε-amino group of Lys. The incorporation of a neutral phosphoryl group with high gas-phase affinity of protons not only improves the ionization efficiency of target molecules and simultaneously decreases the ion suppression effects in MALDI-TOF MS analysis, but also greatly reduces or eliminates the matrix background interferences by suppressing the matrix signals and increasing the molecular weight of the targeted compounds. By applying the N-phosphorylation labeling approach, many amino acids could be detected in serum samples by using MALDI-TOF MS. [ABSTRACT FROM AUTHOR]

In this paper, we report an integrated study of trace element, U-Pb age and Hf isotopic composition of zircons from alkali feldspar granites, granodiorites and diorite enclaves in a recently discovered ring complex at Lianghe in western Yunnan, China. The granitoids showed identical U-Pb ages of 127, 115 and 122 Ma, from felsic to mafic, but had different zircon trace elements and Hf isotopic compositions. Trace element content decreased with a gradual increase in ɛ( t) values of −9.1 to −5.4, −4.5 to 0, and 3.6 to 6.2, respectively. Results indicate that changes in zircon trace elements generally correlate with changes in Hf isotope signatures within single samples and among various granitoids. These relationships reflect the mixing of felsic and mafic magmas. Evidence indicates that depleted mantle-derived mafic magma underplating caused ancient crustal melting, and then formed large-scale granites in Lianghe during the Early Cretaceous. These granodiorites were formed mainly by the mixing of mafic magma and granitic magma. [ABSTRACT FROM AUTHOR]

In this paper, we report an integrated study of U-Pb age and Hf isotope compositions of zircons from biotite plagioclase gneiss at Lianghe in western Yunnan. The zircons preserved inherited core and rim texture. Igneous zircon grains and rims yielded a weighted mean 206Pb/238U age of 120.4±1.7 Ma, their εHf (120 Ma) values were mainly negative ranging from -13.9 to -10.7, with Hf model ages between 1.9 Ga and 2.0 Ga, some zircons had positive εHf (120 Ma) values ranging from 0.2 to 2.1. The inherited cores showed the wide variations in the U-Pb age of 375-1315 Ma. One of them showed the εHf (506 Ma) value of -4.2, it was similar to the gray gneiss of old crust, which εHf (500 Ma) values were negative ranging from -4.5 to -3.3. Combining geological feature and geochemical data, we concluded that the protolith of biotite plagioclase gneiss was old crust-derived tonalitic magma during the early Cretaceous. [ABSTRACT FROM AUTHOR]

1 Linestrength, temperature-dependent self-broadening and narrowing parameters of 10 CH 4 transitions near 7.16 µm were measured over a temperature range of 290 - 1050 K. 2 The self-pressure-shift coefficient was found to change signs from negative to positive with increasing temperature and the Frost's formula fit well its temperature dependence. 3 Several weak transitions excluded from the HITEMP database were observed at elevated temperatures with the line positions given in this work. Absorption lineshapes for 10 CH 4 transitions in the v 2 and v 4 band were measured at high-resolution in a thermodynamically-controlled optical cell using a quantum cascade laser near 7.16 µm. Linestrength, self-broadening, -narrowing, pressure-shift coefficients and their temperature dependence were recorded over a temperature and pressure range of 290–1050 K and 3–80 kPa, respectively. Voigt, Rautian, speed-dependent Voigt profiles were least-squares fit to the measured absorption spectra to determine the best-fit lineshape parameters. Significant collisional-narrowing and speed-dependent effects were observed but no line mixing behaviour was found in pure CH 4 at the experimental conditions. The self-pressure-shift coefficients were found to change signs from negative to positive with increasing temperature and the Frost's formula fit well their temperature dependence for the studied transitions. The measured spectra provided tests of the CH 4 line lists near 1397 cm−1 released in HITEMP 2020 and the recorded spectroscopic parameters compared well with the values in the database. Several weak transitions excluded from the HITEMP database were observed at elevated temperatures with the line positions given here. The analyses of uncertainties in all the measured spectroscopic parameters were also demonstrated in this work. [ABSTRACT FROM AUTHOR]

This study used shock tube and laser absorption spectroscopy to simultaneously measure temperature and CO-concentration time-histories behind reflected shock waves during the pyrolysis and ultra-fuel-rich oxidation of ethanol, diethyl ether, n-heptane, and isooctane. Two transition lines (v " = 0, P8 and v " = 1, R21) in the fundamental vibrational band of CO were selected for temperature and CO-concentration measurements. The temperature simulated based on the measured pressure as inputs agreed well with the measured temperature. The temperature calculated based on the measured pressure and isentropic relationship cannot reveal the real thermodynamic states inside the shock tube for the research in this study. This study compared the measured CO concentration with predictions from several mechanisms. The simulated data agreed well with the measured data only in the limited temperature range. Evident deviations were found between the measured and the simulated data. CO sensitivity analyses were performed to highlight the key reactions influencing CO formation. It was found that: C 2 H 5 OH = CH 3 + CH 2 OH and C 2 H 5 OH = C 2 H 4 + H 2 O dominate the CO formation process during ethanol pyrolysis and ultra-fuel-rich oxidation; C 4 H 10 O (+ M) = C 2 H 5 + C 2 H 5 O (+ M) and C 4 H 10 O + H = C 4 H 9 O + H 2 exert the most evident effects on CO formation during diethyl ether pyrolysis and ultra-fuel-rich oxidation; the selected mechanisms show different reactions influencing CO formation during n-heptane ultra-fuel-rich oxidation; H + O 2 = O + OH and C 2 H 3 (+ M) = C 2 H 2 + H (+ M) show competing behaviors in influencing CO formation during isooctane ultra-fuel-rich oxidation. This study updated rate constant of certain reactions to improve the mechanism performance in predicting CO-formation processes. Further research is necessary to update the rate coefficients for the above-mentioned reactions and improve mechanism performance. [ABSTRACT FROM AUTHOR]

• Absorption line shapes and spectroscopic parameters of the H 2 O transition at 7299.431 cm and the CO transition at 4297.705 cm were measured in perturbers Ar, and He. • The nonlinear pressure dependence of the velocity-changing rates and the speed-dependent coefficients with the corresponding ratios were analyzed by both experiments and simulation. • The Dicke narrowing and speed dependent effects were analyzed and compared in different binary systems. Wavelength modulation-direct absorption spectroscopy (WM-DAS) has been used to measure the absorption line shapes of the H 2 O transition at 7299.431 cm − 1 and the CO transition at 4297.705 cm − 1 perturbed by Ar, N 2 and He. The foreign-gas broadening, narrowing and pressure-shift parameters were determined from various lineshape models at pressures from 1 to 100 kPa. The measured N 2 -broadening coefficients are the largest among the three perturbers and the measured N 2 - and Ar-pressure-shift coefficients are both negative while that for He is positive. The nonlinear pressure dependence of the velocity-changing rates for the Galatry and Rautian profiles and the speed-dependent coefficients for Speed-dependent Voigt profile were all observed for the 6 binary systems. The measured velocity-changing rates were all larger than the corresponding dynamic friction coefficients in H 2 O -Ar/ N 2 /He while smaller than those in CO-Ar/ N 2 /He. The narrowing parameters were also retrieved and compared by taking both the Dicke narrowing and speed dependent effects into account. The partially Correlated quadratic Speed-dependent Hard-Collision profile was simulated and fit by the other simplified profiles to further validate the nonlinear behaviour of the narrowing parameters, which is consistent with the measured results. [ABSTRACT FROM AUTHOR]

The traditional SIRS virus propagation model is used to analyze the malware propagation behavior of wireless rechargeable sensor networks (WRSNs) by adding a new concept: the low-energy status nodes. The SIRS-L model has been developed in this article. Furthermore, the influence of time delay during the charging behavior of the low-energy status nodes needs to be considered. Hopf bifurcation is studied by discussing the time delay that is chosen as the bifurcation parameter. Finally, the properties of the Hopf bifurcation are explored by applying the normal form theory and the center manifold theorem. [ABSTRACT FROM AUTHOR]

With the development of wireless rechargeable sensor networks (WRSNs), many scholars began to attach attention to network security under the spread of viruses. This paper mainly studies a novel low-energy-status-based model SISL (Susceptible, Infected, Susceptible, Low-Energy). The conversion process from low-energy nodes to susceptible nodes is called charging. It is noted that the time delay of the charging process in WRSNs should be considered. However, the charging process and its time delay have not been investigated in traditional epidemic models in WRSNs. Thus, the model SISL is proposed. The basic reproduction number, the disease-free equilibrium point, and the endemic equilibrium point are discussed here. Meanwhile, local stability and global stability of the disease-free equilibrium point and the endemic equilibrium point are analyzed. The addition of the time-delay term needs to be analyzed to determine whether it affects the stability. The intervention treatment strategy under the optimal control is obtained through the establishment of the Hamiltonian function and the application of the Pontryagin principle. Finally, the theoretical results are verified by simulations. [ABSTRACT FROM AUTHOR]

With the rapid development of science and technology, the application of wireless sensor networks (WSNs) is more and more widely. It has been widely concerned by scholars. Viruses are one of the main threats to WSNs. In this paper, based on the principle of epidemic dynamics, we build a SEIR propagation model with the mutated virus in WSNs, where E nodes are infectious and cannot be repaired to S nodes or R nodes. Subsequently, the basic reproduction number R0, the local stability and global stability of the system are analyzed. The cost function and Hamiltonian function are constructed by taking the repair ratio of infected nodes and the repair ratio of mutated infected nodes as optimization control variables. Based on the Pontryagin maximum principle, an optimal control strategy is designed to effectively control the spread of the virus and minimize the total cost. The simulation results show that the model has a guiding significance to curb the spread of mutated virus in WSNs. [ABSTRACT FROM AUTHOR]

• The Loei Fold Belt contains Late Carboniferous (304–299 Ma) basaltic and andesitic tuffaceous rocks and Late Triassic (224–236 Ma) andesite and rhyolite. • The Late Carboniferous and Late Triassic volcanic rocks were formed in a back-arc basin and continental arc setting respectively. • Magmatic events in the Loei Fold Belt occurred in four periods: Ordovician-Silurian, Late Devonian-Middle Permian, Early-Middle Triassic and Late Triassic. • The Nan belt and Luang Prabang-Loei belt were connected in a back-arc basin during Late Devonian to Carboniferous. The Loei Fold Belt is one of the most significant tectonic and metallogenic belts in the Indochina Block. However, origin and tectonic significance of volcanic rocks in several volcanic belts of this fold belt remain ambiguous. In this paper, we present new petrochemical data, zircon U-Pb ages and Lu-Hf isotopic data for volcanic rocks from the Loei Fold Belt in northwestern Laos. The basaltic and andesitic tuffaceous rocks have Late Carboniferous zircon U-Pb ages (304 ± 2.1 Ma and 299 ± 1.8 Ma respectively), and display both MORB-like and arc-like geochemical signatures. Zircon Lu-Hf isotopic analyses give highly positive ε Hf (t) values of 8.99–14.24, indicative of a metasomatic mantle source which formed in a back-arc basin environment. On the other hand, the andesite and rhyolite samples have zircon U-Pb ages ranging from 236 Ma to 224 Ma, erupted during the Late Triassic, and formed in a continental margin arc setting (e.g., enrichment of LREE, depletion in Nb-Ta, Sr, and positive ε Hf (t) values of 9.87–12.25). With a synthesis of available geochronological, petrochemical and isotopic data, magmatic events in the Loei Fold Belt occurred in four periods: Ordovician-Silurian (450–400 Ma), Late Devonian-Middle Permian (ca. 361–265 Ma), Early-Middle Triassic (250–237 Ma) and Late Triassic (ca. 236–200 Ma), with peaks in Triassic and Carboniferous. Accordingly, we propose a tectonic-magmatic evolution model for the Loei Fold Belt. The Luang Prabang-Loei belt was a spreading back-arc basin during the Late Devonian-Middle Permian, and connected with the Nan back-arc basin. The basin expanded to its largest extent in the Permian period and started subduction in the earliest Triassic; the successive subduction did not terminate until the Late Triassic. [ABSTRACT FROM AUTHOR]

A wide-range, calibration-free tunable diode laser spectrometer is established by combining wavelength modulation and direct absorption spectroscopy (WM-DAS) with continuous wave cavity ringdown spectroscopy (CW-CRDS). This spectrometer combines the benefits of absolute concentration measurements, wide range, and high speed, using WM-DAS with enhanced noise reduction in CW-CRDS. The accurate baseline ringdown time, τ0, is calculated by the absorption peak (measured by WM-DAS) and the ringdown time containing gas absorption information (measured by CW-CRDS at the center wavelength of the spectral line). The gas concentration is obtained without measuring τ0 in real time, thus, greatly improving the measuring speed. A WM-DAS/CW-CRDS spectrometer at 1.57 μm for CO detection was assembled for experimental validation of the multiplexing scheme over a concentration ranging from 4 ppm to 1.09% (0.1 MPa, 298 K). The measured concentration of CO at 6374.406 cm−1 shows that the dynamic range of this tunable diode laser absorption spectrometer is extendable up to five orders of magnitude and the corresponding precision is improved. The measurement speed of this spectrometer can extend up to 10 ms, and the detection limit can reach 35 ppb within 25 s. [ABSTRACT FROM AUTHOR]

Shock tube is an effective tool to study the reaction dynamic. As a key parameter, the accuracy measurement of ignition delay time depends on the pressure plateau sustained time. Helium is the most frequently used as driver gas in the shock tube related study. To seek a wider scope of driver gas, H2 was attempted in this paper. The driver capability of H2 and He was compared by theory analysis and experiment, respectively. In addition, to acquire a longer test time, H2/CO2 as driver gas was adopted to test the tailoring condition. Using a 1‐D ideal shock tube assumption, the driver gas tailoring curve is calculated. Results show that the driver capability of H2 is obviously stronger than that of He gas and H2/CO2 group driver gas performs as well as He/N2 group driver gas. The pressure plateau sustained time can extend to 11 ms under tailoring condition by H2/CO2 mixture driving. Furthermore, the comparison of H2‐based and He‐based driver gas models shows no obvious impact on ignition delay measurement. Hence, using H2 as driver gas is more economic because of its cheaper price than He, and it can reduce the experiment risk because of the relative lower diaphragm burst pressure. However, the adverse result is that the vacuum time turns more than one third longer compared with non‐H2 driving mode. [ABSTRACT FROM AUTHOR]

The article highlights the steps of chemical reactions involved in cross-coupling of arylboronic acids.