We present here a series of perylene diimide(PDI)based isomeric conjugated polymers for the application as efficient electron acceptors in all-polymer solar cells(all-PSCs).By copolymerizing PDI monomers with 1,4-diet...We present here a series of perylene diimide(PDI)based isomeric conjugated polymers for the application as efficient electron acceptors in all-polymer solar cells(all-PSCs).By copolymerizing PDI monomers with 1,4-diethynylbenzene(para-linkage)and 1,3-diethynylbenzene(meta-linkage),isomeric PDI based conjugated polymers with parallel and non-parallel PDI units inside backbones were obtained.It was found that para-linked conjugated polymer(PA)showed better solubility,strongerπ-πstacking,more favorable blend morphology,and better photovoltaic performance than those of meta-linked conjugated polymers(PM)did.Device based on PTB7-Th:PA(PTB7-Th:poly{4,8-bis[5-(2-ethylhexyl)-thiophen-2-yl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)-carbonyl]thieno[3,4-b]thiophene-4,6-diyl})showed significantly enhanced photovoltaic performance than that of PTB7-Th:MA(3.29%versus 0.92%).Moreover,the photovoltaic performance of these polymeric acceptors could be further improved via a terpolymeric strategy.By copolymerizing a small amount of meta-linkages into PA,the optimized terpolymeric acceptors enabled to enhance photovoltaic performance with improved the short-circuit current density(Jsc)and fill factor(FF),resulting in an improved power conversion efficiency(PCE)of 4.03%.展开更多
Mixed symmetry states are studied in the framework of the neutron-proton interacting boson model. It is found that some of the mixed symmetry states with moderate high spins change very fast with respect to the Majora...Mixed symmetry states are studied in the framework of the neutron-proton interacting boson model. It is found that some of the mixed symmetry states with moderate high spins change very fast with respect to the Majorana interaction. Under certain conditions, they become the yrast state or yrare state. These states are difficult to decay and become very stable. This study suggests that a possible new mode of isomers may exist due to the special nature in their proton and neutron degrees of freedom.展开更多
Two isomeric metal-organic frameworks(MOFs) with 2-dimensional(2D) and 3-dimensional(3D) topologies both comprised of Cu(Ⅱ) and OTf(OTf = trifluoromethanesulfonate) ions were synthesized and characterized.The CO_2,CH...Two isomeric metal-organic frameworks(MOFs) with 2-dimensional(2D) and 3-dimensional(3D) topologies both comprised of Cu(Ⅱ) and OTf(OTf = trifluoromethanesulfonate) ions were synthesized and characterized.The CO_2,CH_4 and N_2 adsorption properties of the two isomeric MOFs were investigated from 263 K to 298 K at0.1 MPa.The results showed that the 2D MOF exhibited a higher selectivity for CO_2 from CO_2/CH_4 and CH_4from CH_4/N_2 compared to the 3D MOF,even though it possessed a lower surface area and pore volume.The higher adsorption heats of gases on the 2D MOF inferred the strong adsorption potential energy in the layered MOFs.Dynamic separation experiments using CO_2/CH_4 and CH_4/N_2 mixtures on the two MOFs proved that the2 D MOF had a longer elution time than the 3D MOF as well as better separation abilities.展开更多
Two new isomeric Au complexes, Au（PPh3）（bmt）, have been synthesized via the reaction of Au（PPh3）CI with 2-benzimidazolethiol （Hbmt） in dichloromethane （CH2Cl2） solution. Their crystal structures were determi...Two new isomeric Au complexes, Au（PPh3）（bmt）, have been synthesized via the reaction of Au（PPh3）CI with 2-benzimidazolethiol （Hbmt） in dichloromethane （CH2Cl2） solution. Their crystal structures were determined by elemental analysis and single-crystal X-ray diffraction studies. Complex 1 crystallizes in the monoclinic system, space group C2/c with a = 19.589（2）, b = 21.1368（15）, c = 23.424（2） A, β = 108.346（4）°, V= 9206.1（14） A3, Mr = 1216.85, Dc = 1.756 g/cm3, μ = 6.566 mm^-1, F（000） = 4704, Z = 8, the final R = 0.0563 and wR = 0.1028 for 8125 reflections with I 〉 2σ（I）. Complex 2 crystallizes in the monoclinic system, space group P21/n with a = 9.627（3）, b = 21.384（8）, c = 22.308（8） A, β = 92.068（6）°, V= 4590（3） A3, Mr = 1216.85, Dc = 1.761 g/cms, μ = 6.585 mm^-1, F（000） = 2352, Z = 4, the final R = 0.0500 and wR = 0.0883 for 10477 reflections with I 〉 2σ（i）. X-ray diffraction studies reveal that complexes 1 and 2 both feature a 1D chain along the a axis.展开更多
In an attempt to synthesize an indole derivative,methyl 5-nitro-1H-indole-2-carb-oxylate,an isomeric change of methyl 2-[2-（4-nitrophenyl） hydrazono] propanoate from E to Z geometry was observed.The two isomers were...In an attempt to synthesize an indole derivative,methyl 5-nitro-1H-indole-2-carb-oxylate,an isomeric change of methyl 2-[2-（4-nitrophenyl） hydrazono] propanoate from E to Z geometry was observed.The two isomers were determined by single-crystal X-ray diffraction analysis.The Z isomer is stabilized in a six-membered ring conformation constructed by an intramolecular hydrogen bond.This isomeric change added a branched pathway in the mechanism of Fischer indole synthesis.展开更多
On the basis of Hauser-Feshbach theory and some approximations,parametrized formulae of isomeric cross section ratio including two adjustableparameters for(n,t)reaction at 14.6MeV are derived.By fitting these formulae...On the basis of Hauser-Feshbach theory and some approximations,parametrized formulae of isomeric cross section ratio including two adjustableparameters for(n,t)reaction at 14.6MeV are derived.By fitting these formulae to theavailable measured data,parameters are obtained and the systematic behaviour of theisomeric cross section ratio are studied.The isomeric cross section ratio predicted by thepresent work is in good agreement with the limited measured data.展开更多
The^(nat)Mo(γ,xnp)^(95m,g)Nb photonuclear reaction was studied using the electron beam from the NSC KIPT linear accelerator LUE-40.The experiment was performed using the activation and off-lineγ-ray spectrometric te...The^(nat)Mo(γ,xnp)^(95m,g)Nb photonuclear reaction was studied using the electron beam from the NSC KIPT linear accelerator LUE-40.The experiment was performed using the activation and off-lineγ-ray spectrometric technique.The experimental isomeric yield ratio(IR)was determined for the reaction products^(95m,g)Nb at the bremsstrahlung end-point energy E_(γmax)range of 38-93 MeV.The obtained values of IR are in satisfactory agreement with the results of other studies and extend the range of previously known data.The theoretical values of the yields Y_(m,g)(E_(γmax))and the IR for the isomeric pair^(95m,g)Nb from the^(nat)Mo(γ,xnp)reaction were calculated using the partial cross-sectionsσ(E)from the TALYS1.95 code for six different level density models.For the investigated range of E_(γmax),the theoretical dependence of IR on energy was confirmed-the IR smoothly increases with increasing energy.The comparison showed a noticeable difference(more than 3.85 times)in the experimental IR relative to all theoretical estimates.展开更多
The photoneutron reaction^(18)Ta(y,3m)(178m,g)Ta was investigated with the beam from the NSC KIPT electron linear accelerator LUE-40.The measurements were performed using the residual y-activity method.The bremsstrahl...The photoneutron reaction^(18)Ta(y,3m)(178m,g)Ta was investigated with the beam from the NSC KIPT electron linear accelerator LUE-40.The measurements were performed using the residual y-activity method.The bremsstrahlung flux-averaged cross sections((E_(γmax))>.(r(E_(γmax))>m.<r(E_(γmax))g and the isomerie ratio of the re-action products d(E_(γmax))were measured.The theoretical values of the averaged cross-sections and isomeric ratio were calculated using the partial cross-sections from the TALYS1.95 code for different level density models LD 1-6..The obtained experimental d(E_(γmax))agree with the data in the lterature,but differ from the theoretical values in ab-solute magnitude and the behavior of the energy dependence.A comparison of the determined averaged cross-sec-tions with the calculated cross sections showed the best agreement for the case of the LD 5 model.展开更多
The isomeric structures, isomerization and decomposition of silylenoids H(2)SiMX (MX=KF, KCl, LiBr, NaBr and KBr) have been investigated by ab initio molecular orbital theory. These silylenoids have four kinds of very...The isomeric structures, isomerization and decomposition of silylenoids H(2)SiMX (MX=KF, KCl, LiBr, NaBr and KBr) have been investigated by ab initio molecular orbital theory. These silylenoids have four kinds of very similar equilibrium structures. The three-membered ring and p-complex structures should be stable and experimentally detectable. The lifetime of sigma-complex and tetrahedral structures would be very short and experimentally undetectable.展开更多
It remains elusive to realize the distinct catalysis of isomeric catalysts because it becomes challenging to identify structural isomers in the polydisperse nanoparticles.Herein we investigate catalysis of two geometr...It remains elusive to realize the distinct catalysis of isomeric catalysts because it becomes challenging to identify structural isomers in the polydisperse nanoparticles.Herein we investigate catalysis of two geometric isomers for 36-gold-atom nanoclusters with different Au cores arrangements but the same thiolate ligands,thereby providing access to isomer catalysts readily participate in a desired reaction.Compared to the Au_(36)(SR)_(24)with a one-dimensional(1D)layout of Au4 tetrahedral units,the Au_(36)(SR)_(24)with a two-dimensional(2D)layout of Au4 tetrahedral units is more effective for the intramolecular hydroamination of alkyne.Our study suggests that the exposed Au sties of the two Au_(36)(SR)_(24)catalysts favor different reaction intermediates and pathways.The intramolecular H transfer leads to intermediates with the C-N and with C=N for the 1D and 2D Au_(36)(SR)_(24)respectively,and hence the different on-site and off-site pathways for the successive reaction steps account for the different performances of the two Au_(36)(SR)_(24)catalysts.展开更多
In this work two isomeric semi-rigid multi-carboxylate ligands 3,5-bi(3-carboxyphenoxy)benzoic acid(3-H_3BCP), 3,5-bi(4-carboxyphenoxy)benzoic acid(4-H_(3)BCP) and two rigid ligands(bis-triazole 4-(4-(4H-1,2,4-triazol...In this work two isomeric semi-rigid multi-carboxylate ligands 3,5-bi(3-carboxyphenoxy)benzoic acid(3-H_3BCP), 3,5-bi(4-carboxyphenoxy)benzoic acid(4-H_(3)BCP) and two rigid ligands(bis-triazole 4-(4-(4H-1,2,4-triazol-4-yl)phenyl)-4 H-1,2,4-triazole(L^(1)), 2-(1H-pyrazol-3-yl)pyrazine(L^(2))) have been employed to react with Cd(Ⅱ) salts under similar solvothermal reactions. Two novel Cd(Ⅱ) mixed-ligand coordination polymers, namely, {[Cd_3(3-BCP)_(2)(L^(1))]·3H_(2)O}n(1) and [Cd(4-HBCP)(L^(2))]_n(2), have been isolated. 1 displays a rare 2D cluster-based network while 2 displays a 3D supramolecular network through weak interactions. Solid-state luminescent properties and thermal analyses of 1 and 2 also have been determined, indicating strong fluorescent emissions and good thermal stabilities. Different coordination modes of two semi-rigid multi-carboxylate ligands and L^(1) and L^(2) also have been briefly discussed, which also reveal the great potential in the construction of these novel mixed-ligand luminescent frameworks with diverse structural motifs and unique functional properties.展开更多
Electrolytes hold the key to realizing reliable zinc(Zn)anodes.Divergent organic molecules have been proven effective in stabilizing Zn anodes;however,irrational comparisons exist due to the uncontrolled molecular wei...Electrolytes hold the key to realizing reliable zinc(Zn)anodes.Divergent organic molecules have been proven effective in stabilizing Zn anodes;however,irrational comparisons exist due to the uncontrolled molecular weights and functional group amounts.In this work,two“isomeric molecules”:1,2-dimethoxyethane(DME)and 1-methoxy-2-propanol(PM),with identical molecular weights but different functional groups,have been studied as co-solvents in electrolytes,which have delivered distinct electrochemical performance.Experimental and simulative study indicates the dipole moment induced by the hydroxyl groups in PM(higher molecular polarity than ether groups in DME)reconstructs the space charge region,enhances the concentration of Zn^(2+)in the vicinity of Zn anodes,and in-situ derives different solid electrolyte interphase(SEI)models and electrode-electrolyte interfaces,resulting in exceptional cycling stability.Remarkably,the Zn||Cu cell with PM worked over 2000 cycles with high Coulombic efficiency(CE)of 99.7%.The Zn||Zn symmetric cell cycled over 2000 h at 1 mA·cm^(−2),and showed excellent stability at an ultrahigh current density of 10 mA·cm^(−2)and capacity of 20 mAh·cm^(−2)over 200 h(depth of discharge,DOD of 70%).The Zn||sodium vanadate pouch cell with a high mass loading of 6.3 mg·cm^(−2)and a high capacity of 24 mAh demonstrates superior cyclability after 570 h.This work can be a good starting point to provide reliable guidance on electrolyte design for practical aqueous Zn batteries.展开更多
The isomeric ratio of^(184m,g)Re and the half-life of^(184g)Re were measured in the ^(185)Re(n,2n)^(184)Re reaction at 14.8 MeV,and the uncertainty was discussed in detail.The measurements were performed using the act...The isomeric ratio of^(184m,g)Re and the half-life of^(184g)Re were measured in the ^(185)Re(n,2n)^(184)Re reaction at 14.8 MeV,and the uncertainty was discussed in detail.The measurements were performed using the activation method implemented for a rhenium sample using the K-400 neutron generator at the Chinese Academy of Engineering Physics(CAEP).Isomeric state and ground state nuclei of ^(184)Re were identified by their γ-ray spectra.To eliminate the effect of the γ-ray emitted from the isomer on the counting of the ground state characteristic peaks,the isomeric ratio of^(184m,g)Re was calculated to be 0.29±0.11 according to the neutron activation cross-section formula.This result is consistent with previous data within the uncertainty and can be used to determine parameters that characterize the dependence of the level density on the excitation energy and angular momentum.Through exponential function fitting and a detailed discussion of the uncertainty evaluation,the half-life of^(184g)Re was determined as 35.43±0.16 d,which is consistent with the currently recommended value;however,the uncertainty assessment of the latter was barely documented.In addition,this study indicates that the half-life of the ground state can be obtained by eliminating the contamination of γ-rays emitted from the isomer,which provides the possibility of determining the half-lives of nuclides containing isomers.展开更多
The Pleurotus florida is recognized as a medicinal and edible mushroom and the present study intends to reveal the active isomeric molecules from this mushroom.The P.florida was cultivated using different nutrient sup...The Pleurotus florida is recognized as a medicinal and edible mushroom and the present study intends to reveal the active isomeric molecules from this mushroom.The P.florida was cultivated using different nutrient supplements:groundnut husk,maize powder,horse gram powder and coconut oil-cake powder.Horse gram supplement showed the higher mushroom yield and henceit was used for the cultivation of P.florida.Methanolic extract of P.florida was found to be efficient in antioxidant activity among ethanol,aqueous,ethyl acetate and hexane extracts.The bioactive fraction 3-methoxy-4-hydroxy cinnamic acid(PF5)was isolated and purified from the methanolic extract of P.florida by column chromatography,thin layer chromatography(TLC)and gas chromatography-mass spectrum(GC-MS)and further it was characterized by Nuclear magnetic resonance(NMR).The PF5 was tested for its DPPH and reducing power assays,and the IC_(50) values were found to be 21.7μg/mL and 105μg/mL,respectively.We found that the cytotoxic effect of 3-methoxy-4-hydroxy cinnamic acid was tested against the lung cancer cell line using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT),sulphorodamine B(SRB)and trypan blue assays which exhibited a higher cytotoxic effect(CTC_(50),645μg/mL).These results suggested that 3-methoxy-4-hydroxy cinnamic acid from P.florida could be explored as a novel and potent natural antioxidant and cancer preventive agent,alternative to existing synthetic molecules.展开更多
As Internet of Things(IoT)applications expand,Mobile Edge Computing(MEC)has emerged as a promising architecture to overcome the real-time processing limitations of mobile devices.Edge-side computation offloading plays...As Internet of Things(IoT)applications expand,Mobile Edge Computing(MEC)has emerged as a promising architecture to overcome the real-time processing limitations of mobile devices.Edge-side computation offloading plays a pivotal role in MEC performance but remains challenging due to complex task topologies,conflicting objectives,and limited resources.This paper addresses high-dimensional multi-objective offloading for serial heterogeneous tasks in MEC.We jointly consider task heterogeneity,high-dimensional objectives,and flexible resource scheduling,modeling the problem as a Many-objective optimization.To solve it,we propose a flexible framework integrating an improved cooperative co-evolutionary algorithm based on decomposition(MOCC/D)and a flexible scheduling strategy.Experimental results on benchmark functions and simulation scenarios show that the proposed method outperforms existing approaches in both convergence and solution quality.展开更多
The m/z of characteristic ion of the mass spectra of the dichlorocarbene of dodecen-1-ols was used as a parameter to locate the position of double bond in these isomers by a new formula.
Two novel Sn(Ⅱ) supramolecular isomeric frameworks,with the identical formula of {(NH2Me2)2[Sn(BDC)(SO4)]}n,Sn-CP-1-α(1) and Sn-CP-1-β(2)(H2BDC=terephthalic acid) were synthesized under solvothermal condition and f...Two novel Sn(Ⅱ) supramolecular isomeric frameworks,with the identical formula of {(NH2Me2)2[Sn(BDC)(SO4)]}n,Sn-CP-1-α(1) and Sn-CP-1-β(2)(H2BDC=terephthalic acid) were synthesized under solvothermal condition and fully characterized by single crystal X-ray diffraction(SCXRD),Fourier transform infrared spectroscopy(FTIR),ultraviolet-visible spectroscopy(UVVis),elemental analyses,and thermogravimetric analysis(TGA).Interestingly,the structures of 1 and 2 are governed by the temperature of the reaction,suggesting a temperature-induced supramolecular isomerism.The supramolecular isomers are primarily caused by the different bridging alignments of SO42–.Compounds 1 and 2 display 2 D layer and 3 D framework with different topologies,non-interpenetrated 44-sql and two-fold interpenetrated 4-connected dia topology,respectively.Due to Lewis acid properties of coordinatively unsaturated Sn(Ⅱ) sites in CPs,they have been utilized as heterogeneous catalyst for the cyanosilylation of aldehydes with an excellent conversion yield over 99% under solvent-free conditions.展开更多
Inspired by the recent experimental identification of the new isomer with a half-life of （620±150） ns in the very neutron-rich nucleus 180SZr, we apply the projected shell model with axially-deformed bases to d...Inspired by the recent experimental identification of the new isomer with a half-life of （620±150） ns in the very neutron-rich nucleus 180SZr, we apply the projected shell model with axially-deformed bases to discuss possible shapes near the ground state and the nature of the isomer. The structure of the new isomer is investigated by restricting the calculation to prolate and oblate shapes. It is shown that the isomer can be understood as a K-isomer. Meanwhile, the calculation predicts more low-lying high-K configurations, which may be confirmed by future experiments,展开更多
In this paper, based on the two-potential approach combining with the isospin dependent nuclear potential, we systematically compare the α preformation probabilities of odd-A nuclei between nuclear isomeric states an...In this paper, based on the two-potential approach combining with the isospin dependent nuclear potential, we systematically compare the α preformation probabilities of odd-A nuclei between nuclear isomeric states and ground states. The results indicate that during the process of α particle preforming, the low lying nuclear isomeric states are similar to ground states. Meanwhile, in the framework of single nucleon energy level structure, we find that for nuclei with nucleon number below the magic numbers, the α preformation probabilities of high-spin states seem to be larger than low ones. For nuclei with nucleon number above the magic numbers, the α preformation probabilities of isomeric states are larger than those of ground states.展开更多
The proliferation of adulterated health foods and beverages in the market demands a comprehensive analytical strategy to identify the adulterants,particularly those of isomeric phosphodiesterase 5(PDE5)inhibitors.An i...The proliferation of adulterated health foods and beverages in the market demands a comprehensive analytical strategy to identify the adulterants,particularly those of isomeric phosphodiesterase 5(PDE5)inhibitors.An instant coffee premix(ICP)purchased from an online retailer was flagged for suspected adulteration through PDE5 inhibition assay.The ICP was then analysed using suspected-target and non-targeted screenings of a liquid chromatography-quadrupole time-of-flight mass spectrometry.Based on these findings,a PDE5 inhibitor initially assigned as compound X was isolated from the ICP by employing a liquid chromatography-diode array detection before its structural elucidation with liquid chromatography-ultraviolet(LC-UV)spectroscopy and nuclear magnetic resonance(NMR)spectroscopy.The suspected-target screening matched the protonated molecule([MþH]þ)precursor ion of compound X at m/z 499.2310 with two suspected analytes that are structural isomers of one another.The fragmentation patterns of compound X were comparable to those analogues in the dithiocarbodenafil group through the non-targeted screening.These findings,complemented by the LC-UV and NMR spectroscopy data,together with the chromatographic separation of related structural isomers,conclude the identity of compound X.To our best knowledge,this is the first study to report the presence of 3,5-dimethylpiperazinyl-dithiodesmethylcarbodenafil in an ICP sample.展开更多
基金financially supported by the Ministry of Science and Technology of China (No. 2014CB643501)the National Natural Science Foundation of China (Nos. 21634004 and 51403070)+1 种基金the Foundation of Guangzhou Science and Technology Project (No. 201707020019)Zhi-Cheng Hu thanks the financial support from China Postdoctoral Science Foundation (No. 2017M622684)
文摘We present here a series of perylene diimide(PDI)based isomeric conjugated polymers for the application as efficient electron acceptors in all-polymer solar cells(all-PSCs).By copolymerizing PDI monomers with 1,4-diethynylbenzene(para-linkage)and 1,3-diethynylbenzene(meta-linkage),isomeric PDI based conjugated polymers with parallel and non-parallel PDI units inside backbones were obtained.It was found that para-linked conjugated polymer(PA)showed better solubility,strongerπ-πstacking,more favorable blend morphology,and better photovoltaic performance than those of meta-linked conjugated polymers(PM)did.Device based on PTB7-Th:PA(PTB7-Th:poly{4,8-bis[5-(2-ethylhexyl)-thiophen-2-yl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)-carbonyl]thieno[3,4-b]thiophene-4,6-diyl})showed significantly enhanced photovoltaic performance than that of PTB7-Th:MA(3.29%versus 0.92%).Moreover,the photovoltaic performance of these polymeric acceptors could be further improved via a terpolymeric strategy.By copolymerizing a small amount of meta-linkages into PA,the optimized terpolymeric acceptors enabled to enhance photovoltaic performance with improved the short-circuit current density(Jsc)and fill factor(FF),resulting in an improved power conversion efficiency(PCE)of 4.03%.
文摘Mixed symmetry states are studied in the framework of the neutron-proton interacting boson model. It is found that some of the mixed symmetry states with moderate high spins change very fast with respect to the Majorana interaction. Under certain conditions, they become the yrast state or yrare state. These states are difficult to decay and become very stable. This study suggests that a possible new mode of isomers may exist due to the special nature in their proton and neutron degrees of freedom.
基金Supported by National Natural Science Foundation of China(No.21136007,No.51302184)the National Research Fund for Fundamental Key Projects(No.2014CB260402)
文摘Two isomeric metal-organic frameworks(MOFs) with 2-dimensional(2D) and 3-dimensional(3D) topologies both comprised of Cu(Ⅱ) and OTf(OTf = trifluoromethanesulfonate) ions were synthesized and characterized.The CO_2,CH_4 and N_2 adsorption properties of the two isomeric MOFs were investigated from 263 K to 298 K at0.1 MPa.The results showed that the 2D MOF exhibited a higher selectivity for CO_2 from CO_2/CH_4 and CH_4from CH_4/N_2 compared to the 3D MOF,even though it possessed a lower surface area and pore volume.The higher adsorption heats of gases on the 2D MOF inferred the strong adsorption potential energy in the layered MOFs.Dynamic separation experiments using CO_2/CH_4 and CH_4/N_2 mixtures on the two MOFs proved that the2 D MOF had a longer elution time than the 3D MOF as well as better separation abilities.
基金supported by the Youth Science Foundation of Jining University(2009QNKJ07)
文摘Two new isomeric Au complexes, Au（PPh3）（bmt）, have been synthesized via the reaction of Au（PPh3）CI with 2-benzimidazolethiol （Hbmt） in dichloromethane （CH2Cl2） solution. Their crystal structures were determined by elemental analysis and single-crystal X-ray diffraction studies. Complex 1 crystallizes in the monoclinic system, space group C2/c with a = 19.589（2）, b = 21.1368（15）, c = 23.424（2） A, β = 108.346（4）°, V= 9206.1（14） A3, Mr = 1216.85, Dc = 1.756 g/cm3, μ = 6.566 mm^-1, F（000） = 4704, Z = 8, the final R = 0.0563 and wR = 0.1028 for 8125 reflections with I 〉 2σ（I）. Complex 2 crystallizes in the monoclinic system, space group P21/n with a = 9.627（3）, b = 21.384（8）, c = 22.308（8） A, β = 92.068（6）°, V= 4590（3） A3, Mr = 1216.85, Dc = 1.761 g/cms, μ = 6.585 mm^-1, F（000） = 2352, Z = 4, the final R = 0.0500 and wR = 0.0883 for 10477 reflections with I 〉 2σ（i）. X-ray diffraction studies reveal that complexes 1 and 2 both feature a 1D chain along the a axis.
基金Supported by the Natural Science Foundation of Fujian Province (No. 2006 F5058)Fuzhou University (No. XRC-0527)
文摘In an attempt to synthesize an indole derivative,methyl 5-nitro-1H-indole-2-carb-oxylate,an isomeric change of methyl 2-[2-（4-nitrophenyl） hydrazono] propanoate from E to Z geometry was observed.The two isomers were determined by single-crystal X-ray diffraction analysis.The Z isomer is stabilized in a six-membered ring conformation constructed by an intramolecular hydrogen bond.This isomeric change added a branched pathway in the mechanism of Fischer indole synthesis.
文摘On the basis of Hauser-Feshbach theory and some approximations,parametrized formulae of isomeric cross section ratio including two adjustableparameters for(n,t)reaction at 14.6MeV are derived.By fitting these formulae to theavailable measured data,parameters are obtained and the systematic behaviour of theisomeric cross section ratio are studied.The isomeric cross section ratio predicted by thepresent work is in good agreement with the limited measured data.
文摘The^(nat)Mo(γ,xnp)^(95m,g)Nb photonuclear reaction was studied using the electron beam from the NSC KIPT linear accelerator LUE-40.The experiment was performed using the activation and off-lineγ-ray spectrometric technique.The experimental isomeric yield ratio(IR)was determined for the reaction products^(95m,g)Nb at the bremsstrahlung end-point energy E_(γmax)range of 38-93 MeV.The obtained values of IR are in satisfactory agreement with the results of other studies and extend the range of previously known data.The theoretical values of the yields Y_(m,g)(E_(γmax))and the IR for the isomeric pair^(95m,g)Nb from the^(nat)Mo(γ,xnp)reaction were calculated using the partial cross-sectionsσ(E)from the TALYS1.95 code for six different level density models.For the investigated range of E_(γmax),the theoretical dependence of IR on energy was confirmed-the IR smoothly increases with increasing energy.The comparison showed a noticeable difference(more than 3.85 times)in the experimental IR relative to all theoretical estimates.
文摘The photoneutron reaction^(18)Ta(y,3m)(178m,g)Ta was investigated with the beam from the NSC KIPT electron linear accelerator LUE-40.The measurements were performed using the residual y-activity method.The bremsstrahlung flux-averaged cross sections((E_(γmax))>.(r(E_(γmax))>m.<r(E_(γmax))g and the isomerie ratio of the re-action products d(E_(γmax))were measured.The theoretical values of the averaged cross-sections and isomeric ratio were calculated using the partial cross-sections from the TALYS1.95 code for different level density models LD 1-6..The obtained experimental d(E_(γmax))agree with the data in the lterature,but differ from the theoretical values in ab-solute magnitude and the behavior of the energy dependence.A comparison of the determined averaged cross-sec-tions with the calculated cross sections showed the best agreement for the case of the LD 5 model.
基金Project supported by the National Natural Science Fundaion of China.
文摘The isomeric structures, isomerization and decomposition of silylenoids H(2)SiMX (MX=KF, KCl, LiBr, NaBr and KBr) have been investigated by ab initio molecular orbital theory. These silylenoids have four kinds of very similar equilibrium structures. The three-membered ring and p-complex structures should be stable and experimentally detectable. The lifetime of sigma-complex and tetrahedral structures would be very short and experimentally undetectable.
基金supports from Fundamental Research Funds for the Central Universities,Programs for high-level entrepreneurial and innovative talents introduction of Jiangsu Province,and Scientific and Technological Innovation Foundation of Shunde Graduate School of USTB(No.BK19BE024).
文摘It remains elusive to realize the distinct catalysis of isomeric catalysts because it becomes challenging to identify structural isomers in the polydisperse nanoparticles.Herein we investigate catalysis of two geometric isomers for 36-gold-atom nanoclusters with different Au cores arrangements but the same thiolate ligands,thereby providing access to isomer catalysts readily participate in a desired reaction.Compared to the Au_(36)(SR)_(24)with a one-dimensional(1D)layout of Au4 tetrahedral units,the Au_(36)(SR)_(24)with a two-dimensional(2D)layout of Au4 tetrahedral units is more effective for the intramolecular hydroamination of alkyne.Our study suggests that the exposed Au sties of the two Au_(36)(SR)_(24)catalysts favor different reaction intermediates and pathways.The intramolecular H transfer leads to intermediates with the C-N and with C=N for the 1D and 2D Au_(36)(SR)_(24)respectively,and hence the different on-site and off-site pathways for the successive reaction steps account for the different performances of the two Au_(36)(SR)_(24)catalysts.
基金Scientific Research Project of Tianjin Education Commission(2018KJ250)National Natural Science Foundation of China(21501196)。
文摘In this work two isomeric semi-rigid multi-carboxylate ligands 3,5-bi(3-carboxyphenoxy)benzoic acid(3-H_3BCP), 3,5-bi(4-carboxyphenoxy)benzoic acid(4-H_(3)BCP) and two rigid ligands(bis-triazole 4-(4-(4H-1,2,4-triazol-4-yl)phenyl)-4 H-1,2,4-triazole(L^(1)), 2-(1H-pyrazol-3-yl)pyrazine(L^(2))) have been employed to react with Cd(Ⅱ) salts under similar solvothermal reactions. Two novel Cd(Ⅱ) mixed-ligand coordination polymers, namely, {[Cd_3(3-BCP)_(2)(L^(1))]·3H_(2)O}n(1) and [Cd(4-HBCP)(L^(2))]_n(2), have been isolated. 1 displays a rare 2D cluster-based network while 2 displays a 3D supramolecular network through weak interactions. Solid-state luminescent properties and thermal analyses of 1 and 2 also have been determined, indicating strong fluorescent emissions and good thermal stabilities. Different coordination modes of two semi-rigid multi-carboxylate ligands and L^(1) and L^(2) also have been briefly discussed, which also reveal the great potential in the construction of these novel mixed-ligand luminescent frameworks with diverse structural motifs and unique functional properties.
基金We acknowledge the financial support from the Open Research Fund of Songshan Lake Materials Laboratory(No.2021SLABFN04)the National Natural Science Foundation of China(Nos.22005207 and U20A20249)the Regional Innovation and Development Joint Fund,and the Science and Technology Program of Guangdong Province of China(No.2022A0505030028).
文摘Electrolytes hold the key to realizing reliable zinc(Zn)anodes.Divergent organic molecules have been proven effective in stabilizing Zn anodes;however,irrational comparisons exist due to the uncontrolled molecular weights and functional group amounts.In this work,two“isomeric molecules”:1,2-dimethoxyethane(DME)and 1-methoxy-2-propanol(PM),with identical molecular weights but different functional groups,have been studied as co-solvents in electrolytes,which have delivered distinct electrochemical performance.Experimental and simulative study indicates the dipole moment induced by the hydroxyl groups in PM(higher molecular polarity than ether groups in DME)reconstructs the space charge region,enhances the concentration of Zn^(2+)in the vicinity of Zn anodes,and in-situ derives different solid electrolyte interphase(SEI)models and electrode-electrolyte interfaces,resulting in exceptional cycling stability.Remarkably,the Zn||Cu cell with PM worked over 2000 cycles with high Coulombic efficiency(CE)of 99.7%.The Zn||Zn symmetric cell cycled over 2000 h at 1 mA·cm^(−2),and showed excellent stability at an ultrahigh current density of 10 mA·cm^(−2)and capacity of 20 mAh·cm^(−2)over 200 h(depth of discharge,DOD of 70%).The Zn||sodium vanadate pouch cell with a high mass loading of 6.3 mg·cm^(−2)and a high capacity of 24 mAh demonstrates superior cyclability after 570 h.This work can be a good starting point to provide reliable guidance on electrolyte design for practical aqueous Zn batteries.
基金Supported by the National Natural Science Foundation of China(11975113)。
文摘The isomeric ratio of^(184m,g)Re and the half-life of^(184g)Re were measured in the ^(185)Re(n,2n)^(184)Re reaction at 14.8 MeV,and the uncertainty was discussed in detail.The measurements were performed using the activation method implemented for a rhenium sample using the K-400 neutron generator at the Chinese Academy of Engineering Physics(CAEP).Isomeric state and ground state nuclei of ^(184)Re were identified by their γ-ray spectra.To eliminate the effect of the γ-ray emitted from the isomer on the counting of the ground state characteristic peaks,the isomeric ratio of^(184m,g)Re was calculated to be 0.29±0.11 according to the neutron activation cross-section formula.This result is consistent with previous data within the uncertainty and can be used to determine parameters that characterize the dependence of the level density on the excitation energy and angular momentum.Through exponential function fitting and a detailed discussion of the uncertainty evaluation,the half-life of^(184g)Re was determined as 35.43±0.16 d,which is consistent with the currently recommended value;however,the uncertainty assessment of the latter was barely documented.In addition,this study indicates that the half-life of the ground state can be obtained by eliminating the contamination of γ-rays emitted from the isomer,which provides the possibility of determining the half-lives of nuclides containing isomers.
文摘The Pleurotus florida is recognized as a medicinal and edible mushroom and the present study intends to reveal the active isomeric molecules from this mushroom.The P.florida was cultivated using different nutrient supplements:groundnut husk,maize powder,horse gram powder and coconut oil-cake powder.Horse gram supplement showed the higher mushroom yield and henceit was used for the cultivation of P.florida.Methanolic extract of P.florida was found to be efficient in antioxidant activity among ethanol,aqueous,ethyl acetate and hexane extracts.The bioactive fraction 3-methoxy-4-hydroxy cinnamic acid(PF5)was isolated and purified from the methanolic extract of P.florida by column chromatography,thin layer chromatography(TLC)and gas chromatography-mass spectrum(GC-MS)and further it was characterized by Nuclear magnetic resonance(NMR).The PF5 was tested for its DPPH and reducing power assays,and the IC_(50) values were found to be 21.7μg/mL and 105μg/mL,respectively.We found that the cytotoxic effect of 3-methoxy-4-hydroxy cinnamic acid was tested against the lung cancer cell line using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT),sulphorodamine B(SRB)and trypan blue assays which exhibited a higher cytotoxic effect(CTC_(50),645μg/mL).These results suggested that 3-methoxy-4-hydroxy cinnamic acid from P.florida could be explored as a novel and potent natural antioxidant and cancer preventive agent,alternative to existing synthetic molecules.
基金supported by Youth Talent Project of Scientific Research Program of Hubei Provincial Department of Education under Grant Q20241809Doctoral Scientific Research Foundation of Hubei University of Automotive Technology under Grant 202404.
文摘As Internet of Things(IoT)applications expand,Mobile Edge Computing(MEC)has emerged as a promising architecture to overcome the real-time processing limitations of mobile devices.Edge-side computation offloading plays a pivotal role in MEC performance but remains challenging due to complex task topologies,conflicting objectives,and limited resources.This paper addresses high-dimensional multi-objective offloading for serial heterogeneous tasks in MEC.We jointly consider task heterogeneity,high-dimensional objectives,and flexible resource scheduling,modeling the problem as a Many-objective optimization.To solve it,we propose a flexible framework integrating an improved cooperative co-evolutionary algorithm based on decomposition(MOCC/D)and a flexible scheduling strategy.Experimental results on benchmark functions and simulation scenarios show that the proposed method outperforms existing approaches in both convergence and solution quality.
基金Project supported by the National Natural Science Foundation of China (No. 29575190) and the Foundation of Bioorganee and Molecular Engineering Laboratory.
文摘The m/z of characteristic ion of the mass spectra of the dichlorocarbene of dodecen-1-ols was used as a parameter to locate the position of double bond in these isomers by a new formula.
基金supported by the National Natural Science Foundation of China(21822107,21571115,21827801,21671172)the Natural Science Foundation of Shandong Province(JQ201803,ZR2017MB061,ZR2017ZF003)+2 种基金the Taishan Scholar Project of Shandong Province of China(tsqn201812003)the Qilu Youth Scholar Funding of Shandong University and the Fundamental Research Funds of Shandong University(104.205.2.5)the State Key Laboratory of Pollution Control and Resource Reuse Foundation(PCRRF18019)
文摘Two novel Sn(Ⅱ) supramolecular isomeric frameworks,with the identical formula of {(NH2Me2)2[Sn(BDC)(SO4)]}n,Sn-CP-1-α(1) and Sn-CP-1-β(2)(H2BDC=terephthalic acid) were synthesized under solvothermal condition and fully characterized by single crystal X-ray diffraction(SCXRD),Fourier transform infrared spectroscopy(FTIR),ultraviolet-visible spectroscopy(UVVis),elemental analyses,and thermogravimetric analysis(TGA).Interestingly,the structures of 1 and 2 are governed by the temperature of the reaction,suggesting a temperature-induced supramolecular isomerism.The supramolecular isomers are primarily caused by the different bridging alignments of SO42–.Compounds 1 and 2 display 2 D layer and 3 D framework with different topologies,non-interpenetrated 44-sql and two-fold interpenetrated 4-connected dia topology,respectively.Due to Lewis acid properties of coordinatively unsaturated Sn(Ⅱ) sites in CPs,they have been utilized as heterogeneous catalyst for the cyanosilylation of aldehydes with an excellent conversion yield over 99% under solvent-free conditions.
基金supported by the National Natural Science Foundation of China(Grant Nos.11305059,11275067,11135005,11275068 and 11475062)the National Program on Key Basic Research Project(Grant No.2013CB834401)the Open Project Program of State Key Laboratory of Theoretical Physics,Institute of Theoretical Physics,Chinese Academy of Sciences(Grant No.Y5KF141CJ1)
文摘Inspired by the recent experimental identification of the new isomer with a half-life of （620±150） ns in the very neutron-rich nucleus 180SZr, we apply the projected shell model with axially-deformed bases to discuss possible shapes near the ground state and the nature of the isomer. The structure of the new isomer is investigated by restricting the calculation to prolate and oblate shapes. It is shown that the isomer can be understood as a K-isomer. Meanwhile, the calculation predicts more low-lying high-K configurations, which may be confirmed by future experiments,
基金Supported by National Natural Science Foundation of China(11205083)Construct Program of Key Discipline in Hunan Province+3 种基金Rearch Foundation of Education Bureau of Hunan Province,China(15A159)Natural Science Foundation of Hunan Province,China(2015JJ3103,2015JJ2123)Innovation Group of Nuclear and Particle Physics in USCHunan Provincial Innovation Foundation for Postgraduate(CX2015B398)
文摘In this paper, based on the two-potential approach combining with the isospin dependent nuclear potential, we systematically compare the α preformation probabilities of odd-A nuclei between nuclear isomeric states and ground states. The results indicate that during the process of α particle preforming, the low lying nuclear isomeric states are similar to ground states. Meanwhile, in the framework of single nucleon energy level structure, we find that for nuclei with nucleon number below the magic numbers, the α preformation probabilities of high-spin states seem to be larger than low ones. For nuclei with nucleon number above the magic numbers, the α preformation probabilities of isomeric states are larger than those of ground states.
文摘The proliferation of adulterated health foods and beverages in the market demands a comprehensive analytical strategy to identify the adulterants,particularly those of isomeric phosphodiesterase 5(PDE5)inhibitors.An instant coffee premix(ICP)purchased from an online retailer was flagged for suspected adulteration through PDE5 inhibition assay.The ICP was then analysed using suspected-target and non-targeted screenings of a liquid chromatography-quadrupole time-of-flight mass spectrometry.Based on these findings,a PDE5 inhibitor initially assigned as compound X was isolated from the ICP by employing a liquid chromatography-diode array detection before its structural elucidation with liquid chromatography-ultraviolet(LC-UV)spectroscopy and nuclear magnetic resonance(NMR)spectroscopy.The suspected-target screening matched the protonated molecule([MþH]þ)precursor ion of compound X at m/z 499.2310 with two suspected analytes that are structural isomers of one another.The fragmentation patterns of compound X were comparable to those analogues in the dithiocarbodenafil group through the non-targeted screening.These findings,complemented by the LC-UV and NMR spectroscopy data,together with the chromatographic separation of related structural isomers,conclude the identity of compound X.To our best knowledge,this is the first study to report the presence of 3,5-dimethylpiperazinyl-dithiodesmethylcarbodenafil in an ICP sample.
