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The HOBr + HO2 reaction in the absence of water has three different channels for the abstraction of H to generate the corresponding products.

The r-N-GDY filter can be switched between a high-flux “open” state (up to 81.8 L per cm2 per day per MPa) and a “closed” state (4% along the ZZ-direction) by applying tensile strain along different directions, yielding a highly tunable nanopore interface.

The oxidation mechanism of CH3CHCO initiated by OH is systematically studied using quantum theoretical methods. According to thermodynamic research, the dominant channel is the addition of CH3CHCO with OH generating C-IM1 (CH3CHOHCO) and C-IM2 (CH3CHCOOH), and then dissociate to the dominant products P1 (CH3CHO + CO) from C-IM1 with the lowest barrier. The rate constants for CH3CHCO + OH → C-IM1 → P1/CH3CHCO + OH → C-IM2 channels are computed through RRKM theory at 200–2000 K. The obtained overall rate constant at 298 K (7.60 × 10−11 cm3 molecule−1 s−1) is well consistent with the reported experimental value. The atmospheric lifetime of CH3CHCO is estimated to be around 1.83 h.

1,2,3-Trimethylbenzene (1,2,3-TMB) is an important volatile organic compound (VOC) present in petroleum wastewater and the atmosphere. This compound can be degraded by OH radicals via abstraction, addition and substitution mechanisms. Results show that the addition mechanism is dominant and H-abstraction is subdominant, while methyl abstraction and substitution mechanisms are negligible in the gas and aqueous phases. Moreover, H-abstraction products undergo further reactions with O

Two salt cocrystals, C

The widespread coronavirus disease 2019 (COVID-19) has been declared a global health emergency. As one of the most important targets for antibody and drug developments, the Spike RBD-ACE2 interface has received extensive attention. Here, using molecular dynamics simulations, we explicitly analyzed the energetic features of the RBD-ACE2 complex of both SARS-CoV and SARS-CoV-2. Despite the high structural similarity, the binding strength of SARS-CoV-2 to the ACE2 receptor is estimated to be -16.35 kcal mol-1 stronger than that of SARS-CoV. Energy decomposition analyses identified three binding patches in SARS-CoV-2 RBD and eleven key residues (F486, Y505, N501, Y489, Q493, L455, etc.), which are believed to be the main targets for drug development. The dominating forces arise from van der Waals attractions and dehydration of these residues. Compared with SARS-CoV, we found seven mutational sites (K417, L455, A475, G476, E484, Q498 and V503) on SARS-CoV-2 that unexpectedly weakened the RBD-ACE2 binding. Interestingly, the E484 site is recognized to be the most repulsive residue at the RBD-ACE2 interface, indicating that from the energy point of view, a mutation of E484 would be beneficial to RBD-ACE2 binding. This is in line with recent findings that it is mutated by lysine (E484K mutation) in the rapidly spreading variants of COVID-19 belonging to the B.1.351 and P.1 lineages. In addition, this mutation is reported to cause virus neutralization escapes from highly neutralizing COVID-19 convalescent plasma. Thus, further efforts are required to probe its functional relevance. Overall, our results present a systematic understanding of the energetic binding features of SARS-CoV-2 RBD with the ACE2 receptor, which can provide a valuable insight for the design of SARS-CoV-2 drugs and identification of cross-active antibodies.

As one of the volatile organic compounds (VOCs) in the environment, 1,2,4,5-tetramethylbenzene (1,2,4,5-TeMB) present in oily wastewater, and it can occur substitution, abstraction, and addition reactions with OH radicals in the atmosphere and wastewater. Electrostatic potential (ESP) and average local ionization energy (ALIE) prediction indicate that H atoms from CH

The influence of a single water molecule on the BrO + HO2 hydrogen extraction reaction has been explored by taking advantage of CCSD(T)/aug-cc-pVTZ//B3LYP/6-311++G(d,p) method. The reaction in the absence of water have two distinct kinds of H-extraction channels to generate HOBr + O2 and HBr + O3, and the channel of generation of HOBr + O2 occupied the BrO + HO2 reaction. The rate coefficient of the most feasible channel for the BrO + HO2 reaction in the absence of water is estimated to be 1.44 ´ 10-11 cm3 molecule-1 s-1 at 298.15 K, which is consistent with the experiment. The introduction of water made the reaction more complex, but the products are unchanged. Four distinct channels, beginning with HO2…H2O with BrO, H2O…HO2 with BrO, BrO…H2O with HO2, H2O…BrO with HO2 are researched. The most feasible channels, stemming from H2O…HO2 with BrO, and BrO…H2O with HO2, are much slower than the reaction of BrO + HO2 without water, respectively. Thus, the existence of water molecule takes a negative catalytic role for BrO + HO2 reaction.

The potential energy surface for the CH2CCl + O2 reaction has been investigated by using the CCSD(T)/cc-pVTZ//B3LYP/6-311++G(d,p) method. Two type reaction mechanisms have been located. The H-abstraction of CH2CCl by O2 generates CHCCl + HO2 surmounting a 20.86 kcal/mol barrier. The addition between O2 and CH2CCl proceeds to an intermediate CH2CClO2 (IM1t and IM1c) without a barrier, which can further dissociate or isomerize to various products with the complicated processes. The temperature and pressure dependence rate constants for the CH2CCl + O2 reaction were computed by means of multi-channel RRKM-TST theory. Moreover, TDDFT calculations imply that IM1t, IM1c, IM2, IM4, IM5t, and IM5c will photolyze under the sunlight.

The singlet and triplet potential energy surfaces of the HO2 with CF2ClO2 reaction have been probed at the BMC-CCSD/cc-pVTZ level according to the B3LYP/6-311++G(d,p) level obtained geometrical structure. On the singlet PES, the association/dissociation, direct H- abstraction, and SN2 displacement mechanisms have been taken into account. On the triplet PES, SN2 displacement and indirect H- abstraction reaction mechanisms have been investigated and the H- abstraction channel makes more contribution to the CF2ClO2 with HO2 reaction. The rate constants have been computed at 10−10 to 1010 atm and 200–3000 K by RRKM-TST theory. The results show that at T ≤ 600 K, the generation of IM1 (CF2ClO4H) by collisional deactivation is dominant pathway; at high temperatures, the production of P8 (CF2ClOOH + O2(3Σ)) becomes predominate. The predicted data for CF2ClO2 + HO2 agrees closely with available experimental value. Moreover, OH radicals act as inhibitors in the CF2ClOOH→CF2O + HOCl and CF2ClOOH→CFClO + HOF reactions. The dominant products for the reaction of CF2ClOOH + OH are CF2ClO2 + H2O.

CCSD(T)//B3LYP calculations of the potential energy surfaces (PESs) are associated with the rate constants and branch ratio of products using the RRKM (Rice–Ramsperger–Kassel–Marcus) theories to research the mechanism and product distribution of the CHBr2O2 with ClO reaction. The RRKM-computed theory reveals that IM1 (CHBr2OOOCl) are estimated to stable at T ≤ 500 K; the generating P1 (CBr2O + HO2 + Cl) was the primary product at T > 500 K. The lifetimes of CHBr2O2 in the presence of ClO are predicted to 27.8 h. Time-dependent density functional theory (TDDFT) calculations suggest that IM1 (CHBr2OOOCl), IM2 (CHBr2OOClO), and IM3 (CHBr2OClO2) will photolyze under the sunlight.

A global and systematic theoretical research on the singlet and triplet potential energy surfaces (PESs) of the CH2ClO2/CHCl2O2 with ClO reactions are done at the CCSD(T)//B3LYP level and accompanied with RRKM computations to forecast the mechanism and distribution of products. The simulation results revealed that, on the singlet PES, products P1 (CHClO + HO2 + Cl)/P1 (CCl2O + HO2 + Cl) from IM1 (CH2ClOOOCl)/IM1 (CHCl2OOOCl) are forecasted to the primary products of the CH2ClO2/CHCl2O2 + ClO reactions, which are initiated by the oxygen atom of ClO radical addition to the terminal-O atom of CH2ClO2/CHCl2O2 barrierlessly, while other product channels contribute less to the whole reactions owing to higher barriers. Two other isomers, including IM2 (CH2ClOOClO) and IM3 (CH2ClOClO2) for the CH2ClO2 + ClO reaction, and three other isomers, including IM2 (CHCl2OOClO), IM3 (CHCl2OClO2), and IM4 (CHCl2ClO3) for the CHCl2O2 + ClO reaction, could be produced as less significant products. RRKM calculations presented that the initial adducts IM1 (CH2ClOOOCl)/IM1 (CHCl2OOOCl) are the primary products at T

The reaction between CFCl2CH2O2 radicals and ClO was studied using the B3LYP and CCSD(T) methods associated with the 6-311++G(d,p) and cc-pVTZ basis sets, and subsequently RRKM-TST theory was used to predict the thermal rate constants and product distributions. On the singlet PES, the dominant reaction is the addition of the ClO oxygen atom to the terminal-O of CFCl2CH2O2 to generate adduct IM1 (CFCl2CH2OOOCl), and then dissociation to final products P1 (CFCl2CHO + HO2 + Cl) occurs. RRKM theory is employed to calculate the overall and individual rate constants over a wide range of temperatures and pressures. It is predicted that the collision-stabilized IM1 (CFCl2CH2OOOCl) dominates the reaction at 200–500 K (accounting for about 60–100%) and the dominant products are P1 (CFCl2CHO + HO2 + Cl). The yields of the other products are very low and insignificant for the title reaction. The total rate constants exhibit typical “falloff” behavior. The pathways on the triplet PES are less competitive than that on the singlet PES. The calculated overall rate constants are in good agreement with the experimental data. The atmospheric lifetime of CFCl2CH2O2 in ClO is around 2.04 h. TD-DFT calculations imply that IM1 (CFCl2CH2OOOCl), IM2 (CFCl2CH2OOClO) and IM3 (CFCl2CH2OClO2) will photolyze under sunlight.

The singlet and triplet potential energy surfaces for the CH2BrO2 + ClO reaction are studied at the CCSD(T)/cc-pVTZ//B3LYP/6-311++G(d,p) level. CH2BrO2 is revealed to react with ClO through two kinds of mechanisms on the triplet potential energy surface (PES), namely, SN2 displacement and H-abstraction, and the production of P3 (CHBrO2 + HOCl) via H-abstraction is the dominant channel. Addition/elimination and SN2 displacement mechanisms exist on the singlet PES and are more complicated. The RRKM calculations of the mechanism and product distribution in the CH2BrO2 + ClO reaction show that the stabilization of IM1 (CH2BrOOOBr) is dominant at T ≤ 600 K, while the pathway of producing P1 (CHBrO + HO2 + Cl) occupies the entire reaction at T > 600 K. The total rate constants are independent of pressure, while the individual rate constants are sensitive to pressure. The lifetime of CH2BrO2 in the presence of ClO is estimated to be 20.27 h. Moreover, time-dependent density functional theory (TDDFT) calculations suggest that IM1 (CH2BrOOOCl), IM2 (CH2BrOOClO) and IM3 (CH2BrOClO2) will photolyze under the sunlight.

The COVID-19 pandemic caused by SARS-CoV-2 has been declared a global health crisis. The development of anti-SARS-CoV-2 drugs heavily depends on the systematic study of the critical biological processes of key proteins of coronavirus among which the main proteinase (M

Known organophosphorus pesticides are used widely in agriculture to improve the production of crops. Based on the literature, the degradation of some organophosphorus pesticides was studied theoretically. However, the mechanisms and variation of toxicity during the degradation of mevinphos and monocrotophos are still unclear in the environment, especially in wastewater. In this study, the reaction mechanisms for the degradation of the two representative organophosphorus pesticides (i.e., mevinphos and monocrotophos) in presence of OH radicals in the atmosphere and water are proposed using quantum chemical methods wB97-XD/6-311 + +G(3df,2pd)//wB97-XD/6-311 + +G(d,p). Result shows that the dominant channel is OH-addition to the C atom in CC bond with energy barriers being 15.6 and 14.7 kJ/mol, in the atmosphere and water, respectively, for mevinphos. As for monocrotophos, H-abstraction from NH group via barriers of 8.2 and 10.6 kJ/mol is more feasible in both the atmosphere and water. Moreover, the subsequent reactions of the major products in the atmosphere with NO and O

The potential-energy surfaces of the amino radical (NH2) with IO reaction have been studied at the CCSD(T)/cc-pVTZ//MP2/6-311++G(d,p) level. Two kinds of pathways are revealed, namely H-abstraction...

The potential energy surface for the reaction of O(3P) with CH2 = CHCH2F has been studied at the CCSD(T)//M06-2X level of theory. Three different reaction entrances were revealed, namely, terminal-C addition, central-C addition, and H(or F)-abstraction, leading to CH2OCHCH2F (IM1), CH2CHOCH2F (IM2) and HO + C3H4I (OF + C3H5), respectively. The corresponding activation barriers are 3.04 (TS1), 3.71 (TS2), 7.06 (h-TS1), 12.68 (h-TS2), 14.04 (h-TS3) and 63.58 kcal/mol (F-TS1) kcal/mol. Several conceivable decomposition and isomerization channels were also examined for IM1 and IM2. The total and individual rate constants were calculated by using Multichannel RRKM and TST theory over a wide range of temperatures (200−3000 K) and pressures(10−14–1014 Torr).The branching ratios indicate that IM1 is the major product at 200–800 K. The production of P1 (CH2FCHCHO + H)via H-elimination from IM1 becomes dominant at high temperatures.

The degradation reactions of propylamino and dipropylamino radicals in the presence of NO, NO

The O(

4-(2-Methoxyethyl) phenol (MEP) is an significant methoxypheolic compound, which has been shown to play an important role in the formation of secondary organic aerosols(SOA). The present work focuses on the gas-phase oxidation mechanism and kinetics of MEP and OH radical by the density functional theory (DFT). Energetically favourable reaction channels and feasible products were identified. The initial reactions of MEP with OH radical have two different channels: OH addition and H abstraction. Subsequent reaction schemes of main intermediates in the presence of O2 and NOx are investigated using quantum chemical methods at M06-2X/6-311++G(3df,2p)//M06-2X/6-311+G(d,p) level. Ketene, Phenyldiketones and nitrophenol compounds are demonstrated to be possible oxidation products. The total rate constant(1.69×10-11 cm3 molecule-1 s-1) and individual rate constant are calculated using the traditional transition state (TST) theory at 298K and 1atm. The lifetime of MEP is estimated to be 16.4 hours, which provides a comprehensive explanation for atmospheric oxidation pathway of MEP and shows MEP would be removed by OH radical in the atmosphere.

The recommendation algorithm has been applied in many fields and achieved pretty results in recent years. The personas for a large number of dispatchers in the power system are an indispensable step in the process of intelligent recommendation. In order to recommend dispatchers of different levels according to different operation scenarios, the aim of dispatcher personas is the classification of business level. In this paper, we focused on constructing dispatcher personas of Chinese power system. Unlike of the previous research work, we used convolutional neural network(CNN) to create dispatcher personas. The contributions of this paper are reflected in the following aspects: 1. dataset were built automatically based on internal data; 2. a CNN text classifier were trained to construct the dispatcher personas; 3. the effectiveness of the model is proved by experiments on real data. The experimental results show that the method proposed in the paper is superior to the baseline method and the average accuracy is 96%.

4-(2-Methoxyethyl) phenol (MEP) is an significant methoxypheolic compound, which has been shown to play an important role in the formation of secondary organic aerosols(SOA). The present work focuses on the gas-phase oxidation mechanism and kinetics of MEP and OH radical by the density functional theory (DFT). Energetically favourable reaction channels and feasible products were identified. The initial reactions of MEP with OH radical have two different channels: OH addition and H abstraction. Subsequent reaction schemes of main intermediates in the presence of O2 and NOx are investigated using quantum chemical methods at M06-2X/6-311++G(3df,2p)//M06-2X/6-311+G(d,p) level. Ketene, Phenyldiketones and nitrophenol compounds are demonstrated to be possible oxidation products. The total rate constant(1.69×10-11 cm3 molecule-1 s-1) and individual rate constant are calculated using the traditional transition state (TST) theory at 298K and 1atm. The lifetime of MEP is estimated to be 16.4 hours, which provides a comprehensive explanation for atmospheric oxidation pathway of MEP and shows MEP would be removed by OH radical in the atmosphere.

The gas-phase reaction between CFCl2O2 and ClO was researched by means of quantum chemical methods. B3LYP method with the 6-311++G(d,p) basis set was used to obtain the geometric parameters of all stationary points including in the CFCl2O2 + ClO reaction. The singlet and triplet potential energy surfaces were characterized at the CCSD(T)/6-311++G(2d,2p)//B3LYP/6-311++G(d,p) level. Addition/elimination and SN2 displacement reaction mechanisms were identified on the singlet PES, and only substituent reaction mechanism was located on the triplet PES. The dominant reaction takes place on the singlet PES, and the major pathways are CFCl2O2 + ClO → IM1 (CFCl2OOOCl) → IM2 (CFCl2OOClO) → IM3 (CH3OClO2) → P6 (CFClO + (ClO)2). RRKM theory was used to calculate rate constants, which is consistent with the experimental data. The atmospheric lifetime of CFCl2O2 in ClO is around 8.84 h. TD-DFT computations imply that IM1 (CFCl2OOOCl), IM2 (CFCl2OOClO), and IM3 (CFCl2OClO2) will photolyze under the sunlight.

The reaction between CFCl

The singlet and triplet potential energy surfaces for the CH2BrO2• + •Cl reaction have been researched theoretically. All of the probable reaction routes were investigated by using B3LYP and G3(MP2...

Based on electrochemiluminescence resonance energy transfer (ERET) from Ru(bpy)

The singlet and triplet potential energy surfaces of the HO

Intelligent multi-turn dialogue classification uses the whole text as input to predict tags. As one of the most popular research topics in dialogue system, intelligent multi-turn dialogue classification has important research significance in academia and industry. In this paper, we focus on removing redundant information from dialogue text. Multi-turn dialogue classification is essentially a text classification problem. We selects Bert as the core model of multi-turn dialogue classification in view of its strong learning and redundancy removing ability. However, Bert limits the length of its input to 512 and the length of dialogues often exceeds 512. A long text segmentation method based on resampling is presented to solve the problem of input length limitation. The resampling mechanism can also further remove the redundant information in multi-turn dialogues. Experimental results show that the proposed method outperforms all the baselines and achieves an F1 of 53.91%.

Dimetridazole (DMZ) and ornidazole (ONZ) have been widely used to treat anaerobic and protozoal infections. The residues of DMZ/ONZ persist in the water environment. The mechanisms and kinetics of hydroxyl-initiated oxidation, the primary DMZ/ONZ degradation method, were evaluated by quantum chemical methods.·OH-induced degradation of DMZ and ONZ shared many mechanistic and kinetic characteristics. The most feasible degradation pathway involved forming OH-imidazole adducts and NO2. The OH-imidazole adducts were subsequently degraded into double·OH imidazole intermediates. The rate coefficients for·OH degradation of DMZ and ONZ were 4.32 × 109 M−1 s−1 and 4.42 × 109 M−1 s−1 at 298 K, respectively. The lifetimes of DMZ and ONZ treated with·OH at concentrations of 10−9–10−18 mol L−1 at 298 K were τDMZ = 0.231–2.31 × 108 s and τONZ = 0.226–2.26 × 108 s, respectively. Toxicity assessment showed that the first degradation products of DMZ and ONZ exhibited enhanced aquatic toxicity, whereas most of the secondary degradation products were not harmful to aquatic organisms. Some of transformation products were still developmental toxicant or mutagenicity positive.

The degradation reactions of propylamino and dipropylamino radicals in the presence of NO, NO2 and O2 were investigated at the CCSD(T)/6–311++G (2d, 2p)//B3LYP/6–311++G (d,p) levels of theory. Result indicates that nitrosamines, nitramines, nitroso-oxy compounds and imines can be formed at atmosphere. Time dependent density functional theory (TDDFT) calculation shows that nitrosamines and nitroso-oxy compounds can photolyze under sunlight, while nitramines cannot undergo photolysis in the daytime. Moreover, the ecotoxicity assessment result implies that the degradation of propyl-substituted amines by OH radicals, NO and NO2 will reduce their toxicity to fish, daphnia and green algae in the aquatic environment.

The reaction of acetaldehyde with methoxy radical has been investigated theoretically by means of quantum chemistry methods at the BMC-QCISD//B3LYP/6-311+G(d,p) level. The title reaction included three manners, namely, H-abstraction, C-addition-elimination, and C-addition-isomerization-elimination. Based on our calculated results, the formation of adduct IM1 is not a nucleophilic addition reaction, but a π addition reaction. Rice–Ramsperger–Kassel–Marcus-transition state theory calculations are carried out for the total and individual rate constants of the determinant channels over a wide range of temperatures and pressures. The major products for the title reaction are CH3CO and CH3OH. The calculated rate constant (8.73 × 10−15 cm3 molecule−1 s−1) agrees well with the experimental value (k1 = 8.30 × 10−15 cm3 molecule−1 s−1 and 4.23 × 10−15 cm3 molecule−1 s−1).

The mechanism and kinetic for the reaction of Pyrrole + O(3P) has been investigated using CCSD(T)//M06-2X method with multichannel RRKM-TST calculation. On the triplet surface, four product channels corresponding to α-C-addition, β-C-addition, N-addition and direct H-abstraction have been characterized for the first time. The rate constants and branching ratios for twelve product channels are calculated. It is predicted that the total rate coefficients vary with temperature, and exhibit strong positive temperature dependence. Moreover, the total rate coefficients are independence pressure. On the singlet surface, the atomic oxygen can easily add to the C C double bond or the N atom of Pyrrole forming intermediate s-IM1or s-IM2; both approaches were found to be barrierless. It is indicated that the singlet reaction exhibits a marked difference from the triplet reaction. This calculation is useful to simulate experimental investigations of the Pyrrole + O reaction in the singlet surface.