The density functional theory （DFT） is the most popular method for evaluating bond dis- sociation enthalpies （BDEs） of most molecules. Thus, we are committed to looking for alternative methods that can balance the...The density functional theory （DFT） is the most popular method for evaluating bond dis- sociation enthalpies （BDEs） of most molecules. Thus, we are committed to looking for alternative methods that can balance the computational cost and higher precision to the best for large systems. The performance of DFT, double-hybrid DFT, and high-level com- posite methods are examined. The tested sets contain monocyclic and polycyclic aromatic molecules, branched hydrocarbons, small inorganic molecules, etc. The results show that the mPW2PLYP and G4MP2 methods achieve reasonable agreement with the benchmark val- ues for most tested molecules, and the mean absolute deviations are 2.43 and 1.96 kcal/mol after excluding the BDEs of branched hydrocarbons. We recommend the G4MP2 is the most appropriate method for small systems （atoms number≤20）; the double-hybrid DFT methods are advised for large aromatic molecules in medium size （20≤atoms number≤50）, and the double-hybrid DFT methods with empirical dispersion correction are recommended for long-chain and branched hydrocarbons in the same size scope; the DFT methods are ad- vised to apply for large systems （atoms number〉50）, and the M06-2X and B3P86 methods are also favorable. Moreover, the differences of optimized geometry of different methods are discussed and the effects of basis sets for various methods are investigated.展开更多
We report the performance of the first self-aligned InP/InGaAs double heterojunction bipolar transistor （DHBT） produced in China. The device has a 2μm × 12μm U-shaped emitter area and demonstrates a peak comm...We report the performance of the first self-aligned InP/InGaAs double heterojunction bipolar transistor （DHBT） produced in China. The device has a 2μm × 12μm U-shaped emitter area and demonstrates a peak common-emitter DC current gain of over 300,an offset voltage of 0. 16V,a knee voltage of 0.6V,and an open-base breakdown voltage of about 6V. The HBT exhibits good microwave performance with a current gain cutoff fre- quency of 80GHz and a maximum oscillation frequency of 40GHz. These results indicate that this InP/InGaAs DHBT is suitable for low-voltage, low-power, and high-frequency applications.展开更多
A novel face recognition method based on fusion of spatial and frequency features was presented to improve recognition accuracy. Dual-Tree Complex Wavelet Transform derives desirable facial features to cope with the v...A novel face recognition method based on fusion of spatial and frequency features was presented to improve recognition accuracy. Dual-Tree Complex Wavelet Transform derives desirable facial features to cope with the variation due to the illumination and facial expression changes. By adopting spectral regression and complex fusion technologies respectively, two improved neighborhood preserving discriminant analysis feature extraction methods were proposed to capture the face manifold structures and locality discriminatory information. Extensive experiments have been made to compare the recognition performance of the proposed method with some popular dimensionality reduction methods on ORL and Yale face databases. The results verify the effectiveness of the proposed method.展开更多
Cobalt-based oxides,with high abundance,good stability and excellent catalytic performance,are regarded as promising photocatalysts for artificial photosynthetic systems to alleviate foreseeable energy shortages and g...Cobalt-based oxides,with high abundance,good stability and excellent catalytic performance,are regarded as promising photocatalysts for artificial photosynthetic systems to alleviate foreseeable energy shortages and global warming.Herein,for the first time,a series of novel spongy porous CDs@CoOx materials were synthesized to act as an efficient and stable bifunctional photocatalyst for water oxidation and CO2 reduction.Notably,the preparation temperatures visibly influence the morphologies and photocatalytic performances of the CDs@CoOx.Under the optimal conditions,a maximum O2 yield of 40.4% and pretty apparent quantum efficiency(AQE)of 58.6% at 460 nm were obtained over CDs@CoOx-300 for water oxidation.Similarly,the optimized sample CDs@CoOx-300 manifests significant enhancement on the CO2-to-CO conversion with a high selectivity of 89.3% and CO generation rate of 8.1μmol/h,which is superior to most previous cobalt-based catalysts for CO2 reduction.The composite CDs@CoOx-300 not only exposes more active sites but also facilitates electron transport,which results in excellent photocatalytic activity.In addition,the boosted photocatalytic behavior is attributed to the synergistic effect between CoOx and CDs,which was verified by the photocatalytic activity control experiments and electrochemical characterization.The work offers a novel strategy to fabricate a high performance bifunctional photocatalyst for water oxidation and CO2 reduction.展开更多
We report a facile way to prepare sulfur(S) doped Ni4/5 Fe1/5-layered double hydroxide(LDH) electrocatalysts for oxygen evolution reaction(OER). The influence of S doping amount on the OER activity of the resulted Ni ...We report a facile way to prepare sulfur(S) doped Ni4/5 Fe1/5-layered double hydroxide(LDH) electrocatalysts for oxygen evolution reaction(OER). The influence of S doping amount on the OER activity of the resulted Ni Fe-LDHs was studied and the optimal surface S content was ca. 0.43 at%. The developed S-doped Ni Fe-LDH exhibits excellent OER catalyst activity in 1.0 M KOH with overpotential of only 257 m V at the current density of 10 m A cm^-2. Moreover, the catalyst could maintain high activity after 30 h stability test. The high activity of the S-doped Ni Fe-LDH catalysts may originate from the synergistic effect between S and the Fe sites. This work provides a simple but efficient way to improve the OER performance of transition metal oxides/(oxy)hydroxides.展开更多
Exploring highly efficient electrochemical water splitting catalysts has recently attracted extensive research interest from both fundamental researches and practical applications.Transition metal‐based layered doubl...Exploring highly efficient electrochemical water splitting catalysts has recently attracted extensive research interest from both fundamental researches and practical applications.Transition metal‐based layered double hydroxides(LDHs)have been proved to be one of the most efficient materials for oxygen evolution reaction(OER),however,still suffered from low conductivity and sluggish kinetics for hydrogen evolution reaction(HER),which largely inhibited the overall water splitting efficiency.To address this dilemma,enormous approaches including doping regulation,intercalation tuning and defect engineering are therefore rationally designed and developed.Herein,we focus on the recent exciting progress of LDHs hybridization with other two‐dimensional(2D)materials for water splitting reactions,not barely for enhancing OER efficiency but also for boosting HER activity.Particularly,the structural features,morphologies,charge transfer and synergistic effects for the heterostructure/heterointerface that influence the electrocatalytic performance are discussed in details.The hybrid 2D building blocks not only serve as additional conductivity and structural supported but also promote electron transfer at the interfaces and further enhance the electrocatalytic performance.The construction and application of the nanohybrid materials will guide a new direction in developing multifunctional materials based on LDHs,which will contribute to energy conversion and storage.展开更多
Novel hydrophilic NaYF4:Yb^3+,Tm^3+@NaGdF4:Ce^3+,Eu^3+double-jacket microtubes(DJMTs)with upconversion/downconversion dual-mode luminescence were designed and prepared through epitaxial growth of NaGdF4:Ce^3+,Eu^3+she...Novel hydrophilic NaYF4:Yb^3+,Tm^3+@NaGdF4:Ce^3+,Eu^3+double-jacket microtubes(DJMTs)with upconversion/downconversion dual-mode luminescence were designed and prepared through epitaxial growth of NaGdF4:Ce^3+,Eu^3+shell onto the NaYF4:Yb^3+,Tm^3+microtube via poly(acrylic acid)(PAA)mediated hydrothermal method.It is demonstrated that PAA ligand played an important role in guiding the direct growth of NaGdF4:Ce^3+,Eu^3+shell onto the surface of NaYF4:Yb^3+,Tm^3+parent microtubes.The growth of NaGdF4:Ce^3+,Eu^3+shell experienced a crystal phase transition fromβ-NaGdF4 andβ-NaYF4 mixture toβ-NaYF4@NaGdF4 composite crystal,and morphology evolution from mixture ofβ-NaGdF4:Ce^3+,Eu^3+nanorods andβ-NaYF4:Yb^3+,Tm^3+microtubes to NaYF4:Yb^3+,Tm^3+@NaGdF4:Ce^3+,Eu^3+DJMTs.The formation mechanism of DJMTs was the dissolution−renucleation ofβ-NaGdF4:Ce^3+,Eu^3+nanorods and the growth ofβ-NaGdF4:Ce^3+,Eu^3+shell via the classical Ostwald ripening mechanism.The as-prepared DJMTs could exhibit blue upconversion and red downconversion luminescence,which was further made into environmentally benign luminescent inks for creating highly secured and fluorescent-based anti-counterfeiting patterns via inkjet printing.展开更多
Bisphenols containing long aliphatic hydrocarbon side chains were synthesized by the condensation of phenol with aldehyde or ketone in the presence of heteropolyacid. Their structures were characterized by IR, 1H NMR,...Bisphenols containing long aliphatic hydrocarbon side chains were synthesized by the condensation of phenol with aldehyde or ketone in the presence of heteropolyacid. Their structures were characterized by IR, 1H NMR, 13C NMR and element analysis. The experiment results show that when heteropolyacid was used as a catalyst, these bisphenols were obtained in high selectivity and high yields.展开更多
Efficacious regulation of the geometric and electronic structures of carbon nanomaterials via the introduction of defects and their synergy is essential to achieving good electrochemical performance.However,the guidel...Efficacious regulation of the geometric and electronic structures of carbon nanomaterials via the introduction of defects and their synergy is essential to achieving good electrochemical performance.However,the guidelines for designing hybrid materials with advantageous structures and the fundamental understanding of their electrocatalytic mechanisms remain unclear.Herein,superfine Pt and PtCu nanoparticles supported by novel S,N‐co‐doped multi‐walled CNT(MWCNTs)were prepared through the innovative pyrolysis of a poly(3,4‐ethylenedioxythiophene)/polyaniline copolymer as a source of S and N.The uniform wrapping of the copolymer around the MWCNTs provides a high density of evenly distributed defects on the surface after the pyrolysis treatment,facilitating the uniform distribution of ultrafine Pt and PtCu nanoparticles.Remarkably,the Pt_(1)Cu_(2)/SN‐MWCNTs show an obviously larger electroactive surface area and higher mass activity,stability,and CO poisoning resistance in methanol oxidation compared to Pt/SN‐MWCNTs,Pt/S‐MWCNTs,Pt/N‐MWCNTs,and commercial Pt/C.Density functional theory studies confirm that the co‐doping of S and N considerably deforms the CNTs and polarizes the adjacent C atoms.Consequently,both the adsorption of Pt1Cu2 onto the SN‐MWCNTs and the subsequent adsorption of methanol are enhanced;in addition,the catalytic activity of Pt_(1)Cu_(2)/SN‐MWCNTs for methanol oxidation is thermodynamically and kinetically more favorable than that of its CNT and N‐CNT counterparts.This work provides a novel method to fabricate high‐performance fuel cell electrocatalysts with highly dispersed and stable Pt‐based nanoparticles on a carbon substrate.展开更多
Some more new sulfur compounds bearing heterocyclic systems mainly 2-thioxo-1,3,4-thiadiazinone derivatives 2-7 and 3-thioxo-1,2,4-triazole derivatives 9 have been synthetic via alkylation, acylation and condensation ...Some more new sulfur compounds bearing heterocyclic systems mainly 2-thioxo-1,3,4-thiadiazinone derivatives 2-7 and 3-thioxo-1,2,4-triazole derivatives 9 have been synthetic via alkylation, acylation and condensation of dithioic formic acid hydrazide 1 through ring closure reactions with α,β-bi functional groups compounds. Most of the obtained target showed a highly activity towards some microbial in compare with two references antibiotics, Pipercillin and Mycostatine. The structures of the products have been established from their elemental and spectral analysis.展开更多
In order to solve the problem of using new nozzle is proposed in fire rescue robot. middle or low water pressure to form fine water mist, a Existing water mist nozzles are basically used for high pressure and in large...In order to solve the problem of using new nozzle is proposed in fire rescue robot. middle or low water pressure to form fine water mist, a Existing water mist nozzles are basically used for high pressure and in large size, complex structure and poor low pressure atomization effect in comparison with requirement of snake-like fire rescue robots. On the basis of comprehensive typical spray noz- zles, a direct spiral double helix converging nozzle （DSDHCN） is proposed, which has the advanta- ges of small volume, light weight, simple structure, and convenient installation. To make the spray nozzle have good performance, and meet the requirements of more efficient fire extinguishing, a nu- merical study is carried out to analyze the internal and external full flow field of nozzle. A gas-liquid two-phase flow is applied to simulate the external full flow field of nozzle with VOF model in fluent software. The simulation results show the real situation of water flow out of the atomization nozzle and the water jet trajectory. Some simulations about middle or low water pressure direct spiral double he- lix converging optimized nozzle have been done in 30bar pressure. The simulation results show that the optimized nozzle structure not only makes the spray droplets have a good cone angle, but also have a sufficient axial velocity,which proves the structure rationality of the proposed optimized nozzle.展开更多
Methylene-bis[benzobicyclo(diaza-diphenyl) stannoxide,C_(41)H_(34)N_4O_4Sn_2·1/2C_6H_6],Mr=923.19,m.p.126-127℃,triclinic,P1,a=9.780(4),b=14.485(2),c=15.122(6),α=74. 95(3),β=72.21(3),γ=82.68(2)°,V=1967(1)...Methylene-bis[benzobicyclo(diaza-diphenyl) stannoxide,C_(41)H_(34)N_4O_4Sn_2·1/2C_6H_6],Mr=923.19,m.p.126-127℃,triclinic,P1,a=9.780(4),b=14.485(2),c=15.122(6),α=74. 95(3),β=72.21(3),γ=82.68(2)°,V=1967(1) Z=2,Dx=1.56 g/cm￣3, MoKα(λ=0.71073),μ=13.20 cm-1,F(000)=922;final R=0.045, Rw=0.046 for 3637 observed reflections(I≥3σ(I)).The title compound is a bimetallo-heterocyclic complex prepared by condensation.Each tin atom has a trigonal bipyramidal coordination with two oxygen atoms occupying the axial positions.展开更多
The title compound 4, 5-bis ( 2,-dinitrophenylthio )-1, 3-dithiole-2-thione [C3S5(C6H3N2O4)2] crystallizes in the orthogonal system, space group P212121,with a=10. 134(3) , b=20. 488(4), c=9. 656(3)A , V=2005. 1 A3, D...The title compound 4, 5-bis ( 2,-dinitrophenylthio )-1, 3-dithiole-2-thione [C3S5(C6H3N2O4)2] crystallizes in the orthogonal system, space group P212121,with a=10. 134(3) , b=20. 488(4), c=9. 656(3)A , V=2005. 1 A3, D_c=1. 76 g/cm￣3 , Z=4, M.=530. 56, λ=0. 71069 A, F(000)= 1072 , μ=6.1 cm￣(-1), T=296K.Final R= 0. 038, R.= 0. 045 for 1799 reflections with I≥3.5σ(I). In this nonplanar neutral molecule both nitrobenzol rings are approximately perpendicular to the dithiole ring with an asymmetric configuration.展开更多
基金supported by the National Natural Science Foundation of China(91223202)International Science&Technology Cooperation Program of China(2011DFA73410)+1 种基金Tsinghua University Initiative Scientific Research Program,China(20101081907)National Key Basic Research Program of China(973)(2011CB013102)~~
文摘The density functional theory （DFT） is the most popular method for evaluating bond dis- sociation enthalpies （BDEs） of most molecules. Thus, we are committed to looking for alternative methods that can balance the computational cost and higher precision to the best for large systems. The performance of DFT, double-hybrid DFT, and high-level com- posite methods are examined. The tested sets contain monocyclic and polycyclic aromatic molecules, branched hydrocarbons, small inorganic molecules, etc. The results show that the mPW2PLYP and G4MP2 methods achieve reasonable agreement with the benchmark val- ues for most tested molecules, and the mean absolute deviations are 2.43 and 1.96 kcal/mol after excluding the BDEs of branched hydrocarbons. We recommend the G4MP2 is the most appropriate method for small systems （atoms number≤20）; the double-hybrid DFT methods are advised for large aromatic molecules in medium size （20≤atoms number≤50）, and the double-hybrid DFT methods with empirical dispersion correction are recommended for long-chain and branched hydrocarbons in the same size scope; the DFT methods are ad- vised to apply for large systems （atoms number〉50）, and the M06-2X and B3P86 methods are also favorable. Moreover, the differences of optimized geometry of different methods are discussed and the effects of basis sets for various methods are investigated.
文摘We report the performance of the first self-aligned InP/InGaAs double heterojunction bipolar transistor （DHBT） produced in China. The device has a 2μm × 12μm U-shaped emitter area and demonstrates a peak common-emitter DC current gain of over 300,an offset voltage of 0. 16V,a knee voltage of 0.6V,and an open-base breakdown voltage of about 6V. The HBT exhibits good microwave performance with a current gain cutoff fre- quency of 80GHz and a maximum oscillation frequency of 40GHz. These results indicate that this InP/InGaAs DHBT is suitable for low-voltage, low-power, and high-frequency applications.
基金National Natural Science Foundation of China(No.61004088)Key Basic Research Foundation of Shanghai Municipal Science and Technology Commission,China(No.09JC1408000)
文摘A novel face recognition method based on fusion of spatial and frequency features was presented to improve recognition accuracy. Dual-Tree Complex Wavelet Transform derives desirable facial features to cope with the variation due to the illumination and facial expression changes. By adopting spectral regression and complex fusion technologies respectively, two improved neighborhood preserving discriminant analysis feature extraction methods were proposed to capture the face manifold structures and locality discriminatory information. Extensive experiments have been made to compare the recognition performance of the proposed method with some popular dimensionality reduction methods on ORL and Yale face databases. The results verify the effectiveness of the proposed method.
文摘Cobalt-based oxides,with high abundance,good stability and excellent catalytic performance,are regarded as promising photocatalysts for artificial photosynthetic systems to alleviate foreseeable energy shortages and global warming.Herein,for the first time,a series of novel spongy porous CDs@CoOx materials were synthesized to act as an efficient and stable bifunctional photocatalyst for water oxidation and CO2 reduction.Notably,the preparation temperatures visibly influence the morphologies and photocatalytic performances of the CDs@CoOx.Under the optimal conditions,a maximum O2 yield of 40.4% and pretty apparent quantum efficiency(AQE)of 58.6% at 460 nm were obtained over CDs@CoOx-300 for water oxidation.Similarly,the optimized sample CDs@CoOx-300 manifests significant enhancement on the CO2-to-CO conversion with a high selectivity of 89.3% and CO generation rate of 8.1μmol/h,which is superior to most previous cobalt-based catalysts for CO2 reduction.The composite CDs@CoOx-300 not only exposes more active sites but also facilitates electron transport,which results in excellent photocatalytic activity.In addition,the boosted photocatalytic behavior is attributed to the synergistic effect between CoOx and CDs,which was verified by the photocatalytic activity control experiments and electrochemical characterization.The work offers a novel strategy to fabricate a high performance bifunctional photocatalyst for water oxidation and CO2 reduction.
文摘We report a facile way to prepare sulfur(S) doped Ni4/5 Fe1/5-layered double hydroxide(LDH) electrocatalysts for oxygen evolution reaction(OER). The influence of S doping amount on the OER activity of the resulted Ni Fe-LDHs was studied and the optimal surface S content was ca. 0.43 at%. The developed S-doped Ni Fe-LDH exhibits excellent OER catalyst activity in 1.0 M KOH with overpotential of only 257 m V at the current density of 10 m A cm^-2. Moreover, the catalyst could maintain high activity after 30 h stability test. The high activity of the S-doped Ni Fe-LDH catalysts may originate from the synergistic effect between S and the Fe sites. This work provides a simple but efficient way to improve the OER performance of transition metal oxides/(oxy)hydroxides.
文摘Exploring highly efficient electrochemical water splitting catalysts has recently attracted extensive research interest from both fundamental researches and practical applications.Transition metal‐based layered double hydroxides(LDHs)have been proved to be one of the most efficient materials for oxygen evolution reaction(OER),however,still suffered from low conductivity and sluggish kinetics for hydrogen evolution reaction(HER),which largely inhibited the overall water splitting efficiency.To address this dilemma,enormous approaches including doping regulation,intercalation tuning and defect engineering are therefore rationally designed and developed.Herein,we focus on the recent exciting progress of LDHs hybridization with other two‐dimensional(2D)materials for water splitting reactions,not barely for enhancing OER efficiency but also for boosting HER activity.Particularly,the structural features,morphologies,charge transfer and synergistic effects for the heterostructure/heterointerface that influence the electrocatalytic performance are discussed in details.The hybrid 2D building blocks not only serve as additional conductivity and structural supported but also promote electron transfer at the interfaces and further enhance the electrocatalytic performance.The construction and application of the nanohybrid materials will guide a new direction in developing multifunctional materials based on LDHs,which will contribute to energy conversion and storage.
基金Project(51874129)supported by the National Natural Science Foundation of ChinaProjects(2018JJ3115,2019JJ60049)supported by the Science Foundation of Hunan Province,ChinaProjects(19B153,19B158)supported by the Scientific Research Fund of Hunan Provincial Education Department,China。
文摘Novel hydrophilic NaYF4:Yb^3+,Tm^3+@NaGdF4:Ce^3+,Eu^3+double-jacket microtubes(DJMTs)with upconversion/downconversion dual-mode luminescence were designed and prepared through epitaxial growth of NaGdF4:Ce^3+,Eu^3+shell onto the NaYF4:Yb^3+,Tm^3+microtube via poly(acrylic acid)(PAA)mediated hydrothermal method.It is demonstrated that PAA ligand played an important role in guiding the direct growth of NaGdF4:Ce^3+,Eu^3+shell onto the surface of NaYF4:Yb^3+,Tm^3+parent microtubes.The growth of NaGdF4:Ce^3+,Eu^3+shell experienced a crystal phase transition fromβ-NaGdF4 andβ-NaYF4 mixture toβ-NaYF4@NaGdF4 composite crystal,and morphology evolution from mixture ofβ-NaGdF4:Ce^3+,Eu^3+nanorods andβ-NaYF4:Yb^3+,Tm^3+microtubes to NaYF4:Yb^3+,Tm^3+@NaGdF4:Ce^3+,Eu^3+DJMTs.The formation mechanism of DJMTs was the dissolution−renucleation ofβ-NaGdF4:Ce^3+,Eu^3+nanorods and the growth ofβ-NaGdF4:Ce^3+,Eu^3+shell via the classical Ostwald ripening mechanism.The as-prepared DJMTs could exhibit blue upconversion and red downconversion luminescence,which was further made into environmentally benign luminescent inks for creating highly secured and fluorescent-based anti-counterfeiting patterns via inkjet printing.
基金Supported by the National Natural Science Foundation of China(No.5 94 6 30 0 1)
文摘Bisphenols containing long aliphatic hydrocarbon side chains were synthesized by the condensation of phenol with aldehyde or ketone in the presence of heteropolyacid. Their structures were characterized by IR, 1H NMR, 13C NMR and element analysis. The experiment results show that when heteropolyacid was used as a catalyst, these bisphenols were obtained in high selectivity and high yields.
文摘Efficacious regulation of the geometric and electronic structures of carbon nanomaterials via the introduction of defects and their synergy is essential to achieving good electrochemical performance.However,the guidelines for designing hybrid materials with advantageous structures and the fundamental understanding of their electrocatalytic mechanisms remain unclear.Herein,superfine Pt and PtCu nanoparticles supported by novel S,N‐co‐doped multi‐walled CNT(MWCNTs)were prepared through the innovative pyrolysis of a poly(3,4‐ethylenedioxythiophene)/polyaniline copolymer as a source of S and N.The uniform wrapping of the copolymer around the MWCNTs provides a high density of evenly distributed defects on the surface after the pyrolysis treatment,facilitating the uniform distribution of ultrafine Pt and PtCu nanoparticles.Remarkably,the Pt_(1)Cu_(2)/SN‐MWCNTs show an obviously larger electroactive surface area and higher mass activity,stability,and CO poisoning resistance in methanol oxidation compared to Pt/SN‐MWCNTs,Pt/S‐MWCNTs,Pt/N‐MWCNTs,and commercial Pt/C.Density functional theory studies confirm that the co‐doping of S and N considerably deforms the CNTs and polarizes the adjacent C atoms.Consequently,both the adsorption of Pt1Cu2 onto the SN‐MWCNTs and the subsequent adsorption of methanol are enhanced;in addition,the catalytic activity of Pt_(1)Cu_(2)/SN‐MWCNTs for methanol oxidation is thermodynamically and kinetically more favorable than that of its CNT and N‐CNT counterparts.This work provides a novel method to fabricate high‐performance fuel cell electrocatalysts with highly dispersed and stable Pt‐based nanoparticles on a carbon substrate.
文摘Some more new sulfur compounds bearing heterocyclic systems mainly 2-thioxo-1,3,4-thiadiazinone derivatives 2-7 and 3-thioxo-1,2,4-triazole derivatives 9 have been synthetic via alkylation, acylation and condensation of dithioic formic acid hydrazide 1 through ring closure reactions with α,β-bi functional groups compounds. Most of the obtained target showed a highly activity towards some microbial in compare with two references antibiotics, Pipercillin and Mycostatine. The structures of the products have been established from their elemental and spectral analysis.
基金Supported by the National Natural Science Foundation of China(No.61105086)Self-Planned Task(SKLRS-2010-MS-12)of State Key Laboratory of Robotics and System(HIT)Hubei Province Natural Science Foundation(No.2010CDB03405)
文摘In order to solve the problem of using new nozzle is proposed in fire rescue robot. middle or low water pressure to form fine water mist, a Existing water mist nozzles are basically used for high pressure and in large size, complex structure and poor low pressure atomization effect in comparison with requirement of snake-like fire rescue robots. On the basis of comprehensive typical spray noz- zles, a direct spiral double helix converging nozzle （DSDHCN） is proposed, which has the advanta- ges of small volume, light weight, simple structure, and convenient installation. To make the spray nozzle have good performance, and meet the requirements of more efficient fire extinguishing, a nu- merical study is carried out to analyze the internal and external full flow field of nozzle. A gas-liquid two-phase flow is applied to simulate the external full flow field of nozzle with VOF model in fluent software. The simulation results show the real situation of water flow out of the atomization nozzle and the water jet trajectory. Some simulations about middle or low water pressure direct spiral double he- lix converging optimized nozzle have been done in 30bar pressure. The simulation results show that the optimized nozzle structure not only makes the spray droplets have a good cone angle, but also have a sufficient axial velocity,which proves the structure rationality of the proposed optimized nozzle.
文摘Methylene-bis[benzobicyclo(diaza-diphenyl) stannoxide,C_(41)H_(34)N_4O_4Sn_2·1/2C_6H_6],Mr=923.19,m.p.126-127℃,triclinic,P1,a=9.780(4),b=14.485(2),c=15.122(6),α=74. 95(3),β=72.21(3),γ=82.68(2)°,V=1967(1) Z=2,Dx=1.56 g/cm￣3, MoKα(λ=0.71073),μ=13.20 cm-1,F(000)=922;final R=0.045, Rw=0.046 for 3637 observed reflections(I≥3σ(I)).The title compound is a bimetallo-heterocyclic complex prepared by condensation.Each tin atom has a trigonal bipyramidal coordination with two oxygen atoms occupying the axial positions.
文摘The title compound 4, 5-bis ( 2,-dinitrophenylthio )-1, 3-dithiole-2-thione [C3S5(C6H3N2O4)2] crystallizes in the orthogonal system, space group P212121,with a=10. 134(3) , b=20. 488(4), c=9. 656(3)A , V=2005. 1 A3, D_c=1. 76 g/cm￣3 , Z=4, M.=530. 56, λ=0. 71069 A, F(000)= 1072 , μ=6.1 cm￣(-1), T=296K.Final R= 0. 038, R.= 0. 045 for 1799 reflections with I≥3.5σ(I). In this nonplanar neutral molecule both nitrobenzol rings are approximately perpendicular to the dithiole ring with an asymmetric configuration.
