The reactions of anionic zirconium oxide clusters ZrxOy- with C2H6 and C4H10 are investi-gated by a time of flight mass spectrometer coupled with a laser vaporization cluster source.Hydrogen containing products Zr2O5H...The reactions of anionic zirconium oxide clusters ZrxOy- with C2H6 and C4H10 are investi-gated by a time of flight mass spectrometer coupled with a laser vaporization cluster source.Hydrogen containing products Zr2O5H- and Zr3O7H- are observed after the reaction. Den-sity functional theory calculations indicate that the hydrogen abstraction is favorable in the reaction of Zr2O5- with C2H6, which supports that the observed Zr2O5H- and Zr3O7H- are due to hydrogen atom abstraction from the alkane molecules. This work shows a newpossible pathway in the reaction of zirconium oxide cluster anions with alkane molecules.展开更多
Pentachlorophenol, a widespread environmental pollutant that is possibly carcinogenic to humans, is metabolically oxidized to tetrachloroquinone （TCBQ） which can result in DNA damage. We have investigated the photoc...Pentachlorophenol, a widespread environmental pollutant that is possibly carcinogenic to humans, is metabolically oxidized to tetrachloroquinone （TCBQ） which can result in DNA damage. We have investigated the photochemical reaction dynamics of TCBQ with two pyrimidine type nucleobases （thymine and uracil） upon UVA （355 ran） excitation using the technique of nanosecond time-resolved laser flash photolysis. It has been found that 355 nm excitation populates TCBQ molecules to their triplet state 3TCBQ＊, which are highly reactive towards thymine or uracil and undergo two parallel reactions, the hydrogen abstraction and electron transfer, leading to the observed photoproducts of TCBQH. and TCBQ.- in transient absorption spectra. The concomitantly produced nucleobase radicals and radical cations are expected to induce a series of oxidative or strand cleavage damage to DNA afterwards. By characterizing the photochemical hydrogen abstraction and electron transfer reactions, our results provide potentially important molecular reaction mechanisms for understanding the carcinogenic effects of pentachlorophenol and its metabolites TCBQ.展开更多
International Journal of Minerals,Metallurgy and Materials is dedicated to the publication and the dissemination of original research articles(and occasional invited reviews)in the fields of Minerals,Metallurgy and Ma...International Journal of Minerals,Metallurgy and Materials is dedicated to the publication and the dissemination of original research articles(and occasional invited reviews)in the fields of Minerals,Metallurgy and Materials.It is covered by EI Compendex,SCI Expanded,Chemical Abstract,etc.展开更多
The Chinese Journal of Natural Medicines(CJNM,ISSN 2095-6975),founded in 2003 and sponsored by China Pharmaceutical University,is a peer-reviewed journal published monthly in print by Science Press and online by Elsev...The Chinese Journal of Natural Medicines(CJNM,ISSN 2095-6975),founded in 2003 and sponsored by China Pharmaceutical University,is a peer-reviewed journal published monthly in print by Science Press and online by Elsevier.CJNM is currently indexed in Science Citation Index Expanded(SCIE),MEDLINE,BIOSIS Previews,BIOSIS Toxicology,CAB Abstracts.展开更多
In the context of modern software development characterized by increasing complexity and compressed development cycles,traditional static vulnerability detection methods face prominent challenges including high false ...In the context of modern software development characterized by increasing complexity and compressed development cycles,traditional static vulnerability detection methods face prominent challenges including high false positive rates and missed detections of complex logic due to their over-reliance on rule templates.This paper proposes a Syntax-Aware Hierarchical Attention Network(SAHAN)model,which achieves high-precision vulnerability detection through grammar-rule-driven multi-granularity code slicing and hierarchical semantic fusion mechanisms.The SAHAN model first generates Syntax Independent Units(SIUs),which slices the code based on Abstract Syntax Tree(AST)and predefined grammar rules,retaining vulnerability-sensitive contexts.Following this,through a hierarchical attention mechanism,the local syntax-aware layer encodes fine-grained patterns within SIUs,while the global semantic correlation layer captures vulnerability chains across SIUs,achieving synergistic modeling of syntax and semantics.Experiments show that on benchmark datasets like QEMU,SAHAN significantly improves detection performance by 4.8%to 13.1%on average compared to baseline models such as Devign and VulDeePecker.展开更多
The mechanisms and kinetics of the gas phase reactions that the hydrogen atom in formyl fluoride （FCHO） abstracted by OH in the presence of water, formic acid （FA）, or sulfuric acid （SA） are theoretically invest...The mechanisms and kinetics of the gas phase reactions that the hydrogen atom in formyl fluoride （FCHO） abstracted by OH in the presence of water, formic acid （FA）, or sulfuric acid （SA） are theoretically investigated at the CCSD（T）/6-311＋＋G（3df, 3pd）//MO6-2X/6- 311＋＋G（3df, 3pd） level of theory. The calculated results show that the barriers of the transition states involving catalysts are lowered to -2.89, -6.25, and -7.76 kcal/mol from 3.64 kcal/mol with respect to the separate reactants, respectively, which reflects that those catalysts play an important role in reducing the barrier of the hydrogen abstraction reaction of FCHO with OH. Additionally, using conventional transition state theory with Eckart tun- neling correction, the kinetic data demonstrate that the entrance channel X…FCHO＋OH （X=H2O, FA, or SA） is significantly more favorable than the pathway X…OH＋FCHO. More- over, the rate constants of the reactions of FCHO with OH radical with H2O, FA, or SA introduced are computed to be smaller than that of the naked OH＋FCHO reaction because the concentration of the formed X…FCHO or X…OH complex is quite low in the atmosphere.展开更多
针对现有视频摘要算法以及摘要评价方法未能充分考虑工业智能终端所感知的视频数据特点以及工业智能感知相关应用需求,改写了代表性与多样性两种评价约束,基于此,结合DWConv(Depthwise Convolution)与ConvLSTM(Convolutional Long Short...针对现有视频摘要算法以及摘要评价方法未能充分考虑工业智能终端所感知的视频数据特点以及工业智能感知相关应用需求,改写了代表性与多样性两种评价约束,基于此,结合DWConv(Depthwise Convolution)与ConvLSTM(Convolutional Long Short-Term Memory)设计了一种混合双向多层的工业视频摘要方案。该方案由全局粗粒度特征提取、局部细粒度特征提取、反馈更新以及以查询为驱动的特征融合这4部分组成。为应对工业数据高冗余性、感知的视频噪声大等特点,围绕着ConvLSTM与注意力机制搭建全局特征提取模块;为充分提取视频数据的时空特性,结合注意力机制与DB-DWConvLSTM构建局部特征提取模块;针对工业数据具有的周期性与局部稳定性,借助残差网络思想,设计了融合DWConv反馈模块;为了更加凸显关键帧特征,便于更好的筛选关键帧,研究以查询驱动的特征融合模块。为验证方案的有效性与可行性,将该方案在TVSum与SumMe两个数据集上进行分析验证。实验结果表明:该方案在交叉验证、消融实验以及对比分析中都有着较好的性能。展开更多
基金This work was supported by the Chinese Academy of Sciences （Hundred Talents Fund）, the National Natural Science Foundation of China （No.20703048 and No.20803083）, and the Center of Molecular Science Foundation of Institute of Chemistry, Chinese Academy of Sciences （No.CMS-LX200902）.
文摘The reactions of anionic zirconium oxide clusters ZrxOy- with C2H6 and C4H10 are investi-gated by a time of flight mass spectrometer coupled with a laser vaporization cluster source.Hydrogen containing products Zr2O5H- and Zr3O7H- are observed after the reaction. Den-sity functional theory calculations indicate that the hydrogen abstraction is favorable in the reaction of Zr2O5- with C2H6, which supports that the observed Zr2O5H- and Zr3O7H- are due to hydrogen atom abstraction from the alkane molecules. This work shows a newpossible pathway in the reaction of zirconium oxide cluster anions with alkane molecules.
基金This work was supported by the National Natural Science Foundation of China （No.20903104, No.2107320L and No.20733005） and the Chinese Academy of Sciences.
文摘Pentachlorophenol, a widespread environmental pollutant that is possibly carcinogenic to humans, is metabolically oxidized to tetrachloroquinone （TCBQ） which can result in DNA damage. We have investigated the photochemical reaction dynamics of TCBQ with two pyrimidine type nucleobases （thymine and uracil） upon UVA （355 ran） excitation using the technique of nanosecond time-resolved laser flash photolysis. It has been found that 355 nm excitation populates TCBQ molecules to their triplet state 3TCBQ＊, which are highly reactive towards thymine or uracil and undergo two parallel reactions, the hydrogen abstraction and electron transfer, leading to the observed photoproducts of TCBQH. and TCBQ.- in transient absorption spectra. The concomitantly produced nucleobase radicals and radical cations are expected to induce a series of oxidative or strand cleavage damage to DNA afterwards. By characterizing the photochemical hydrogen abstraction and electron transfer reactions, our results provide potentially important molecular reaction mechanisms for understanding the carcinogenic effects of pentachlorophenol and its metabolites TCBQ.
文摘International Journal of Minerals,Metallurgy and Materials is dedicated to the publication and the dissemination of original research articles(and occasional invited reviews)in the fields of Minerals,Metallurgy and Materials.It is covered by EI Compendex,SCI Expanded,Chemical Abstract,etc.
文摘The Chinese Journal of Natural Medicines(CJNM,ISSN 2095-6975),founded in 2003 and sponsored by China Pharmaceutical University,is a peer-reviewed journal published monthly in print by Science Press and online by Elsevier.CJNM is currently indexed in Science Citation Index Expanded(SCIE),MEDLINE,BIOSIS Previews,BIOSIS Toxicology,CAB Abstracts.
基金supported by the research start-up funds for invited doctor of Lanzhou University of Technology under Grant 14/062402。
文摘In the context of modern software development characterized by increasing complexity and compressed development cycles,traditional static vulnerability detection methods face prominent challenges including high false positive rates and missed detections of complex logic due to their over-reliance on rule templates.This paper proposes a Syntax-Aware Hierarchical Attention Network(SAHAN)model,which achieves high-precision vulnerability detection through grammar-rule-driven multi-granularity code slicing and hierarchical semantic fusion mechanisms.The SAHAN model first generates Syntax Independent Units(SIUs),which slices the code based on Abstract Syntax Tree(AST)and predefined grammar rules,retaining vulnerability-sensitive contexts.Following this,through a hierarchical attention mechanism,the local syntax-aware layer encodes fine-grained patterns within SIUs,while the global semantic correlation layer captures vulnerability chains across SIUs,achieving synergistic modeling of syntax and semantics.Experiments show that on benchmark datasets like QEMU,SAHAN significantly improves detection performance by 4.8%to 13.1%on average compared to baseline models such as Devign and VulDeePecker.
文摘The mechanisms and kinetics of the gas phase reactions that the hydrogen atom in formyl fluoride （FCHO） abstracted by OH in the presence of water, formic acid （FA）, or sulfuric acid （SA） are theoretically investigated at the CCSD（T）/6-311＋＋G（3df, 3pd）//MO6-2X/6- 311＋＋G（3df, 3pd） level of theory. The calculated results show that the barriers of the transition states involving catalysts are lowered to -2.89, -6.25, and -7.76 kcal/mol from 3.64 kcal/mol with respect to the separate reactants, respectively, which reflects that those catalysts play an important role in reducing the barrier of the hydrogen abstraction reaction of FCHO with OH. Additionally, using conventional transition state theory with Eckart tun- neling correction, the kinetic data demonstrate that the entrance channel X…FCHO＋OH （X=H2O, FA, or SA） is significantly more favorable than the pathway X…OH＋FCHO. More- over, the rate constants of the reactions of FCHO with OH radical with H2O, FA, or SA introduced are computed to be smaller than that of the naked OH＋FCHO reaction because the concentration of the formed X…FCHO or X…OH complex is quite low in the atmosphere.
文摘针对现有视频摘要算法以及摘要评价方法未能充分考虑工业智能终端所感知的视频数据特点以及工业智能感知相关应用需求,改写了代表性与多样性两种评价约束,基于此,结合DWConv(Depthwise Convolution)与ConvLSTM(Convolutional Long Short-Term Memory)设计了一种混合双向多层的工业视频摘要方案。该方案由全局粗粒度特征提取、局部细粒度特征提取、反馈更新以及以查询为驱动的特征融合这4部分组成。为应对工业数据高冗余性、感知的视频噪声大等特点,围绕着ConvLSTM与注意力机制搭建全局特征提取模块;为充分提取视频数据的时空特性,结合注意力机制与DB-DWConvLSTM构建局部特征提取模块;针对工业数据具有的周期性与局部稳定性,借助残差网络思想,设计了融合DWConv反馈模块;为了更加凸显关键帧特征,便于更好的筛选关键帧,研究以查询驱动的特征融合模块。为验证方案的有效性与可行性,将该方案在TVSum与SumMe两个数据集上进行分析验证。实验结果表明:该方案在交叉验证、消融实验以及对比分析中都有着较好的性能。
