The Casimir energy of massive scalar field with hybrid （Diriehlet-Neumann） boundary condition is calculated. In order to regularize the model, the typical methods named as mode summation method and Green＇s function...The Casimir energy of massive scalar field with hybrid （Diriehlet-Neumann） boundary condition is calculated. In order to regularize the model, the typical methods named as mode summation method and Green＇s function method are used respectively. It is found that the regularized zero-point energy density depends on the scalar field＇s mass. When the field is massless, the result is consistent with previous literatures.展开更多
To further test whether polynitriprismanes are capable of being potential high energy density materials （HEDMs）, extensive theoretical calculations were carried out to investigate on a series of polynitrotriprisman...To further test whether polynitriprismanes are capable of being potential high energy density materials （HEDMs）, extensive theoretical calculations were carried out to investigate on a series of polynitrotriprismanes （PNNPs）： C6H6-.（NO2）. （n=1-6） Heats of formation （HOFs）, strain energies （SE）, and disproportionation energy （DE） were obtained using B3LYP/6-311＋G（2df, 2p）//B3LYP/6-31G＊ method by designing different isodesmic reactions, respectively. Detonation properties of PNNPs were obtained by the well-known KAMLET-JACOBS equations, using the predicted densities （p） obtained by Monte Carlo method and HOFs. It is found that they increase as the number of nitro groups n varies from 1 to 6, and PNNPs with n〉4 have excellent detonation properties The relative stability and the pyrolysis mechanism of PNNPs were evaluated by the calculated bond dissociation energy （BDE）. The comparison of BDE suggests that rupturing the C--C bond is the trigger for thermolysis of PNNPs. The computed BDE for cleavage of C--C bond （88.5 kJ/mol） further demonstrates that only the hexa-nitrotriprismane can be considered to be the target of HEDMs.展开更多
Modulating the oxidation states of transition metal species has been regarded as a promising strategy to tune the redox activity and achieve more active sites in electrode materials.In this work,a unique three-dimensi...Modulating the oxidation states of transition metal species has been regarded as a promising strategy to tune the redox activity and achieve more active sites in electrode materials.In this work,a unique three-dimensional(3D)honeycomb-like cobalt sulfide(Co_(x)S_(y))network organized by cross-linked nanosheets(Co_(x)S_(y)-T NSs)was prepared via a simple triethanolamine(TEOA)-assisted self-templating strategy.Interestingly,it has been found for the first time that the introduction of TEOA in the reaction effectively increases the ratio of high-valence Co^(3+)in the final product.Benefiting from the synergetic effect of the tailored high-valence Co^(3+)with the 3D network structure,the Co_(x)S_(y)-T NS electrode exhibits a maximum specific capacity of 351 mA h g^(-1)(2635 F g^(-1))at 5 A g^(-1)as well as excellent cycling stability.Furthermore,with the solid-state asymmetric supercapacitor(ASC)constructed based on the Co_(x)S_(y)-T NSs and activated carbon(AC)electrodes,a high energy density up to 81.62 W h kg^(-1)has been achieved at the power density of 0.81 kW kg^(-1)and 96.2%capacitance is preserved after 7000 cycles,indicating robust cycling stability.This result highlights the simple approach of simultaneously tailoring highvalence metal species and constructing 3D network structure toward high-performance electrode materials for energy storage and conversion.展开更多
In this paper,we report a high-performance selfsupported supercapacitor electrode composed of a cracked bark-shaped Ni-Co-Mn ternary metallic sulfide(NiCoMnS4)nanostructure on carbon cloth prepared by a simple one-ste...In this paper,we report a high-performance selfsupported supercapacitor electrode composed of a cracked bark-shaped Ni-Co-Mn ternary metallic sulfide(NiCoMnS4)nanostructure on carbon cloth prepared by a simple one-step hydrothermal process and subsequent electrochemical treatment.The electrode delivers a high specific discharge capacity of up to 2470.4 F g^(-1) at 1 A g^(-1) and high rate performances of1635.6 F g^(-1) at 10 A g^(-1) and 910.2 F g^(-1) even at 32 A g^(-1).Cycling tests indicate that NiCoMnS_(4) could maintain >91.1% of its initial capacity and nearly 100% Coulombic efficiency over10,000 cycles at 8 A g^(-1).An aqueous asymmetric supercapacitor assembled with NiCoMnS_(4) as the cathode,activated carbon as the anode,and 1 mol L^(-1) KOH as the electrolyte delivers an energy density of 68.2 W h kg^(-1)at 850.1 W kg^(-1) and capacity retention of 92.5% after 10,000 cycles at 4 A g^(-1).Given the excellent performance and simple material preparation of our proposed device,this study provides a valuable foundation for the development of self-supported metallic sulfide-based electrodes with high electrochemical properties for potential application in aqueous asymmetric supercapacitors.展开更多
Polaron induced double electron in a quantum dot is investigated using the exact diagonalization techniques and the compact density-matrix approach. The dependence of nonlinear optical processes on the incident photon...Polaron induced double electron in a quantum dot is investigated using the exact diagonalization techniques and the compact density-matrix approach. The dependence of nonlinear optical processes on the incident photon energies and the polaronic effect are brought out. The linear, third order non-linear optical absorption coefficients and the refractive index changes of singlet and triplet states as a function of photon energy are obtained with and without the inclusion of polaronic effect. It is found that the geometrical confinement and the effect of polaron have great influence on the optical properties of dots.展开更多
The uneven deposition of lithium(Li) on current collectors causes serious dendrite growth and volume expansion. Commercial foamed copper(Cu) current collectors are unsuitable for Li anodes because of their large volum...The uneven deposition of lithium(Li) on current collectors causes serious dendrite growth and volume expansion. Commercial foamed copper(Cu) current collectors are unsuitable for Li anodes because of their large volume and mass and lithiophobic nature. Herein, a three-dimensional(3 D) copper@tin(Cu@Sn) nanocone current collector with small volume, light weight, and lithiophilic nature was prepared by a simple electrodeposition method. The synergy of the nanoconical structure and lithiophilic Sn promotes the even deposition of Li and effectively inhibits the formation of Li dendrites. The resultant half batteries exhibit high Coulombic efficiency of 97.6% after 100 cycles at 1 mA cm^(-2), and the symmetrical Li battery demonstrates a prolonged lifespan of over 600 h at 1 mA cm^(-2). The full battery based on organic liquid electrolyte with LiFePO_(4) also exhibits a long lifespan of 550 cycles with high capacity retention of 95.1% at 1 C.Moreover, 3 D Cu@Sn nanocone-based solid-state batteries exhibit excellent electrochemical performance and show no decay after 500 cycles at 1 C. Our work provides a strategy for fabricating 3 D current collectors for high-energy-density Li metal batteries.展开更多
基金supported by National Natural Science Foundation of China under Grant Nos.10773002 and 10875012the National Fundamental Research Program of China under Grant No.2003CB716302
文摘The Casimir energy of massive scalar field with hybrid （Diriehlet-Neumann） boundary condition is calculated. In order to regularize the model, the typical methods named as mode summation method and Green＇s function method are used respectively. It is found that the regularized zero-point energy density depends on the scalar field＇s mass. When the field is massless, the result is consistent with previous literatures.
基金Projects(2006DFA41090,2007DFA40680) supported by the International Cooperation Project on Traditional Chinese Medicines of Ministry of Science and Technology of ChinaProject(20475066) supported by the National Natural Science Foundation of China
文摘To further test whether polynitriprismanes are capable of being potential high energy density materials （HEDMs）, extensive theoretical calculations were carried out to investigate on a series of polynitrotriprismanes （PNNPs）： C6H6-.（NO2）. （n=1-6） Heats of formation （HOFs）, strain energies （SE）, and disproportionation energy （DE） were obtained using B3LYP/6-311＋G（2df, 2p）//B3LYP/6-31G＊ method by designing different isodesmic reactions, respectively. Detonation properties of PNNPs were obtained by the well-known KAMLET-JACOBS equations, using the predicted densities （p） obtained by Monte Carlo method and HOFs. It is found that they increase as the number of nitro groups n varies from 1 to 6, and PNNPs with n〉4 have excellent detonation properties The relative stability and the pyrolysis mechanism of PNNPs were evaluated by the calculated bond dissociation energy （BDE）. The comparison of BDE suggests that rupturing the C--C bond is the trigger for thermolysis of PNNPs. The computed BDE for cleavage of C--C bond （88.5 kJ/mol） further demonstrates that only the hexa-nitrotriprismane can be considered to be the target of HEDMs.
基金the National Natural Science Foundation of China(21671173)Zhejiang Provincial Ten Thousand Talent Program(2017R52043)。
文摘Modulating the oxidation states of transition metal species has been regarded as a promising strategy to tune the redox activity and achieve more active sites in electrode materials.In this work,a unique three-dimensional(3D)honeycomb-like cobalt sulfide(Co_(x)S_(y))network organized by cross-linked nanosheets(Co_(x)S_(y)-T NSs)was prepared via a simple triethanolamine(TEOA)-assisted self-templating strategy.Interestingly,it has been found for the first time that the introduction of TEOA in the reaction effectively increases the ratio of high-valence Co^(3+)in the final product.Benefiting from the synergetic effect of the tailored high-valence Co^(3+)with the 3D network structure,the Co_(x)S_(y)-T NS electrode exhibits a maximum specific capacity of 351 mA h g^(-1)(2635 F g^(-1))at 5 A g^(-1)as well as excellent cycling stability.Furthermore,with the solid-state asymmetric supercapacitor(ASC)constructed based on the Co_(x)S_(y)-T NSs and activated carbon(AC)electrodes,a high energy density up to 81.62 W h kg^(-1)has been achieved at the power density of 0.81 kW kg^(-1)and 96.2%capacitance is preserved after 7000 cycles,indicating robust cycling stability.This result highlights the simple approach of simultaneously tailoring highvalence metal species and constructing 3D network structure toward high-performance electrode materials for energy storage and conversion.
基金supported by the National Natural Science Foundation of China(61376068,11304132,11304133 and11504147)the Fundamental Research Funds for the Central Universities(lzujbky-2017-178 and lzujbky-2017-181)。
文摘In this paper,we report a high-performance selfsupported supercapacitor electrode composed of a cracked bark-shaped Ni-Co-Mn ternary metallic sulfide(NiCoMnS4)nanostructure on carbon cloth prepared by a simple one-step hydrothermal process and subsequent electrochemical treatment.The electrode delivers a high specific discharge capacity of up to 2470.4 F g^(-1) at 1 A g^(-1) and high rate performances of1635.6 F g^(-1) at 10 A g^(-1) and 910.2 F g^(-1) even at 32 A g^(-1).Cycling tests indicate that NiCoMnS_(4) could maintain >91.1% of its initial capacity and nearly 100% Coulombic efficiency over10,000 cycles at 8 A g^(-1).An aqueous asymmetric supercapacitor assembled with NiCoMnS_(4) as the cathode,activated carbon as the anode,and 1 mol L^(-1) KOH as the electrolyte delivers an energy density of 68.2 W h kg^(-1)at 850.1 W kg^(-1) and capacity retention of 92.5% after 10,000 cycles at 4 A g^(-1).Given the excellent performance and simple material preparation of our proposed device,this study provides a valuable foundation for the development of self-supported metallic sulfide-based electrodes with high electrochemical properties for potential application in aqueous asymmetric supercapacitors.
文摘Polaron induced double electron in a quantum dot is investigated using the exact diagonalization techniques and the compact density-matrix approach. The dependence of nonlinear optical processes on the incident photon energies and the polaronic effect are brought out. The linear, third order non-linear optical absorption coefficients and the refractive index changes of singlet and triplet states as a function of photon energy are obtained with and without the inclusion of polaronic effect. It is found that the geometrical confinement and the effect of polaron have great influence on the optical properties of dots.
基金supported by the National Natural Science Foundation of China (51771094 and 21835004)the National Key R&D Program of China (2016YFB0901500)+1 种基金the Ministry of Education of China (B12015 and IRT13R30)Tianjin Natural Science Foundation (18JCZDJC31500)。
文摘The uneven deposition of lithium(Li) on current collectors causes serious dendrite growth and volume expansion. Commercial foamed copper(Cu) current collectors are unsuitable for Li anodes because of their large volume and mass and lithiophobic nature. Herein, a three-dimensional(3 D) copper@tin(Cu@Sn) nanocone current collector with small volume, light weight, and lithiophilic nature was prepared by a simple electrodeposition method. The synergy of the nanoconical structure and lithiophilic Sn promotes the even deposition of Li and effectively inhibits the formation of Li dendrites. The resultant half batteries exhibit high Coulombic efficiency of 97.6% after 100 cycles at 1 mA cm^(-2), and the symmetrical Li battery demonstrates a prolonged lifespan of over 600 h at 1 mA cm^(-2). The full battery based on organic liquid electrolyte with LiFePO_(4) also exhibits a long lifespan of 550 cycles with high capacity retention of 95.1% at 1 C.Moreover, 3 D Cu@Sn nanocone-based solid-state batteries exhibit excellent electrochemical performance and show no decay after 500 cycles at 1 C. Our work provides a strategy for fabricating 3 D current collectors for high-energy-density Li metal batteries.
