The chaotic motion behavior of the rectangular conductive thin plate that is simply supported on four sides by airflow andmechanical external excitation in a magnetic field is studied.According to Kirchhoff’s thin pl...The chaotic motion behavior of the rectangular conductive thin plate that is simply supported on four sides by airflow andmechanical external excitation in a magnetic field is studied.According to Kirchhoff’s thin plate theory,considering geometric nonlinearity and using the principle of virtualwork,the nonlinearmotion partial differential equation of the rectangular conductive thin plate is deduced.Using the separate variable method and Galerkin’s method,the system motion partial differential equation is converted into the general equation of the Duffing equation;the Hamilton system is introduced,and the Melnikov function is used to analyze the Hamilton system,and obtain the critical surface for the existence of chaos.The bifurcation diagram,phase portrait,time history response and Poincarémap of the vibration system are obtained by numerical simulation,and the correctness is demonstrated.The results showthatwhen the ratio of external excitation amplitude to damping coefficient is higher than the critical surface,the system will enter chaotic state.The chaotic motion of the rectangular conductive thin plate is affected by different magnetic field distributions and airflow.展开更多
American foreign policies have observed guiding principles of democracy, yet an overemphasis on political values leads to more conflicts than mutual understandings in today's world. Therefore, this paper proposes tha...American foreign policies have observed guiding principles of democracy, yet an overemphasis on political values leads to more conflicts than mutual understandings in today's world. Therefore, this paper proposes that exploring diplomatic implications of "women's work" provides new insights into cultural values of the Four Freedomsmmajor pillars supporting modern American liberalism. This paper foregrounds the domestic and diplomatic significance of "women's work" by analyzing women's contributions as laborers at home, in the labor force, and in American consumer society. As American women participated in the paid labor force and took up most consumptive activities, women outside America also worked hard to provide food and care for families. This paper argues that a more comprehensive definition of"women's work" is not only indispensable for the development of American industry, consumer society, and the expansion of marketplace, but integrates a system of dualisms separating wage labor and housework, or divisions between spheres of men and women. Moreover, investigations into hidden values of women's work alleviate worries arising from information revolution and economic globalization. Moreover, placing women's work in perspective enables diplomats to see through factors leading to international hostilities, to reduce conflicts arising from information revolution and economic globalization, and to understand America's soft power pertinently.展开更多
With the development of network technology and information technology, electronic commerce as a new business model wiht itsnew trading ideas-+, In changing the traditional business structure,but also gradually changi...With the development of network technology and information technology, electronic commerce as a new business model wiht itsnew trading ideas-+, In changing the traditional business structure,but also gradually changing people’s shopping patterns and consumptionpatterns,Online shopping has become the preferred way of shopping.Changes in consumption patterns will inevitably lead to new problems inthe process of consumption,and the development speed of the problem in sync with the development speed of network economy,as far as therenewal speed of laws and regulations is concerned,this asymmetric development is bound to bring great inconvenience to the consumer rights innetwork transactions.In this paper, from the angle of legal protection,the protection of consumer rights and interests in network transactions areexpounded,analysis of the current situation and reasons of the consumers’ rights and interests are infringed upon in the network transaction,learnfrom the experience of foreign consumer rights and interests protection,In order to put forward effective suggestions on the system constructionof the protection of consumer rights and interests.展开更多
The Professor's House presents the readers pictures with striking consumer culture characteristics. With abundant goods of sign values, conspicuous consumption, swelling-desire-stimulating power and the individual...The Professor's House presents the readers pictures with striking consumer culture characteristics. With abundant goods of sign values, conspicuous consumption, swelling-desire-stimulating power and the individuals' efforts to construct their identities through consumption as dominant features, consumer culture exerts negative and even devastating effects on the characters in the novel. Theories of ecocriticism shed new lights on the interpretation of consumerism reflected in the novel, especially on analyzing how the consumer culture makes the characters suffer from split personality, alienation from nature, society, and even from themselves and their spiritual ecology.展开更多
Conductivities tomography with the interactions of magnetic field, electrical field, and ultrasound field is presented in this paper. We utilize a beam of ultrasound in scanning mode instead of the traditional ultraso...Conductivities tomography with the interactions of magnetic field, electrical field, and ultrasound field is presented in this paper. We utilize a beam of ultrasound in scanning mode instead of the traditional ultrasound field generated by point source. Many formulae for the reconstruction of conductivities are derived from the voltage signals detected by two electrodes arranged somewhere on tissue's surface. In a forward problem, the numerical solutions of ultrasound fields generated by the piston transducer are calculated using the angular spectrum method and its Green's function is designed approximately in far fields. In an inverse problems, the magneto-acousto-electrical voltage signals are proved to satisfy the wave equations if the voltage signals are extended to the whole region from the boundary locations of transducers. Thus the time-reversal method is applied to reconstructing the curl of the reciprocal current density. In addition, a least square iteration method of recovering conductivities from reciprocal current densities is discussed.展开更多
The conductance of pyrite-bearing laminated and dispersed shaly sands is not well understood and resistivity models for pyrite-bearing shaly sands are nonexistent. Thus, we first synthesize clean pyrite-matrix samples...The conductance of pyrite-bearing laminated and dispersed shaly sands is not well understood and resistivity models for pyrite-bearing shaly sands are nonexistent. Thus, we first synthesize clean pyrite-matrix samples, and quartz-matrix samples with variable laminated shale, dispersed shale, and pyrite content and then perform petrophysics experiments to assess the effect of pyrite content on the conductivity of pyrite-bearing shaly sands. Second, based on the differences in conductivity and conduction pathways and geometries because of the variable composition of the pyrite-bearing laminated and dispersed shaly sands, we divide the shaly sands into their components, i.e., laminated shale, quartz grains, pyrite grains, hydrocarbon, dispersed shale, microscopic capillary water, and mobile water. A generalized resistivity model is proposed to describe the conductivity of pyrite- bearing laminated and dispersed shaly sands, based on the combined conductivity differential equation and generalized Archie equation. In the generalized resistivity model, the conductivity differential equation is used to describe the conductivity of dispersed inclusions in a host, whereas the generalized Archie equation is used to describe the conductivity of two conducting phases. Moreover, parallel conductance theory is used to describe the conductivity of dispersed shaly sands and laminated shale. Theoretical analysis suggests that the proposed model satisfies the physical constraints and the model and experimental results agree. The resistivity and resistivity index of shaly sands decrease with increasing conductivity and pyrite. Finally, the accuracy of the resistivity model is assessed based on experimental data from 46 synthetic core samples with different oil saturation. The model can describe the conductivity of clean pyrite-matrix samples, and quartz-matrix samples with different volumes of laminated shale, dispersed shale, and pyrite. An accurate saturation model of pyrite-bearing laminated and dispersed shaly sands is thus obtained and the log data interpretation in complex shaly sands can improve with the proposed model.展开更多
Five kinds of molybdovanadophosphoric acids H_7[P_2Mo_(17)VO_(62)],H_8[P_2Mo_(16)·V_2O_(62)],H_9 [P_2Mo_(15)V_3O_(62)],H_8[P_2Mo_(14)V_4O_(61)(H_2O)]and H_9[P_2Mo_(13)V_5O_(61)(H_2O)]have been synthesized.Their p...Five kinds of molybdovanadophosphoric acids H_7[P_2Mo_(17)VO_(62)],H_8[P_2Mo_(16)·V_2O_(62)],H_9 [P_2Mo_(15)V_3O_(62)],H_8[P_2Mo_(14)V_4O_(61)(H_2O)]and H_9[P_2Mo_(13)V_5O_(61)(H_2O)]have been synthesized.Their protop conductivities(C) have been measured.The effects of three main factors (frequency,hydration numbers,temperature)on the conductivity have been investigated.In some degree,heteropoly compounds with different structures give a different conductivity.展开更多
AIM: To investigate the effect of tetramethylpyrazine (TMP), an active compound from Ligustium Wollichii Franchat, on electrolyte transport across the distal colon of rodents and the mechanism involved.METHODS: Th...AIM: To investigate the effect of tetramethylpyrazine (TMP), an active compound from Ligustium Wollichii Franchat, on electrolyte transport across the distal colon of rodents and the mechanism involved.METHODS: The short-circuit current (Isc) technique in conjunction with pharmacological agents and specific inhibitors were used in analyzing the electrolyte transport across the distal colon of rodents. The underlying cellular signaling mechanism was investigated by radioimmunoassay analysis (RIA) and a special mouse model of cystic fibrosis.RESULTS: IMP stimulated a conoentration-dependent rise in ISCl, which was dependent on both Cl^- and HCO3^-, and inhibited by apical application of diphenylamine-2,2'-dicarboxylic acid (DPC) and glibenclamide, but resistant to 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid disodium salt hydrate (DIDS). Removal of Na^+ from basolateral solution almost completely abolished the Isc response to TMP, but it was insensitive to apical Na^+ replacement or apical Na^+ channel blocker, amiloride. Pretreatment of colonic mucosa with BAPTA-AM, a membrane-permeable selective Ca2+ chelator, did not significantly alter the TMP-induced Iso No additive effect of forskolin and 3-isobutyl-l-methylxanthine ([BMX) was observed on the TMP-induced Isc, but it was significantly reduced by a protein kinase A inhibitor, H89.RIA results showed that TMP (1 mmol/L) elicited a significant increase in cellular cAMP production, which was similar to that elicited by the adenylate cyclase activator, forskolin (10μmol/L). The TMP-elicited Isc as well as forskolin- or IBMX-induced Isc were abolished in mice with homozygous mutation of the cystic fibrosis transmembrane conductance regulator (CFTR) presenting defective CFTR functions and secretions.CONCLUSION: TMP may stimulate cAMP-dependent and CFTR-mediated Cl^- and HCO3^- secretion. This may have implications in the future development of alternative treatment for constipation.展开更多
A series of aluminium-containing α-type hydrated zirconium hydrogen phosphates,Zr_(1-x)Alx (H_(1+x/2)PO_4 )_2 with x=0-0.06,were hydrothermally synthesized and characterizedby means of X-ray diffraction,differential ...A series of aluminium-containing α-type hydrated zirconium hydrogen phosphates,Zr_(1-x)Alx (H_(1+x/2)PO_4 )_2 with x=0-0.06,were hydrothermally synthesized and characterizedby means of X-ray diffraction,differential thermal analysis and thermogravimetric analysis.The proton conductivity,1.2×10 ̄(-4) S·cm ̄(-1)at 180℃ was found in Zr_(0.98)Al_(0.02)(H_(1.01)PO_4)_2·H_2O.Humidity-sensing measurements were carried out at 120℃ and 140℃ respectively.Even a limited substitution of Al for Zr can enhance both proton conductivity and humidity sensitivity.展开更多
Lithium metal has gained extensive attention as the most ideal candidate for next-generation battery anode owing to the ultrahigh specific capacity and the lowest electrochemical potential.However,uncontrollable dendr...Lithium metal has gained extensive attention as the most ideal candidate for next-generation battery anode owing to the ultrahigh specific capacity and the lowest electrochemical potential.However,uncontrollable dendrite growth and huge volume variation extremely restrict the future deployment of lithium metal batteries.Herein,we report metal chalcogenide SnSSe with unique nanoplate stacking structure as a robust substrate for stable Li metal anode.During the initial Li plating process,lithiophilic Li_(22)Sn_(5) alloy and Li_(2)S/Li_(2)Se sites are obtained via in-situ electrochemical reaction of Li metal and SnSSe.Density functional theory(DFT)calculation demonstrates that the formed Li_(2)S/Li_(2)Se achieves low Li diffusion energy barrier,ensuring rapid Li~+migration.Li_(22)Sn_(5) alloy provides strong nucleation sites,promoting uniform Li nucleation.Furthermore,in-situ optical microscopy analysis suggests that the synthesized effect fundamentally inhibits lithium dendrite growth.Consequently,SnSSe modified Cu foil delivered an ultralow nucleation overpotential,superior cycling stability with 450 cycles(Coulombic efficiency,>98%),and excellent plating/stripping behavior over 2200 h at 0.5 mA cm^(-2).Moreover,the brilliant reversible cycles and rate capability were also realized in Li@SnSSe//LiFePO_(4)(LFP)full cell,shedding light on the feasibility of SnSSe for stable and dendrite-free lithium metal anode.展开更多
To study the variation pattern of aero conductivity of different porous media under low pressure conditions, three kinds of media are selected. These include sandy clay loam, fine sand, and medium sand, and air us flu...To study the variation pattern of aero conductivity of different porous media under low pressure conditions, three kinds of media are selected. These include sandy clay loam, fine sand, and medium sand, and air us fluid to conduct soil column ventilation tests. Pressure at both ends of the colruns is measured under different ventilation flow rates during testing. The test results show that the aero conductivity, solved by Darcy's law, is not a coustant. It is a variable, which increases first when air flow velocity is less than 0. 258 7 cm/s for sandy clay loam, 0. 637 3 cm/s for fine sand and then decreases when air flow velocity is bigger than that with the increase of the ventilation flow rate when the medium is determined. By analyzing various factors that influence the flow resistance, the reasons for variation in aero conductivity are found us follows: first, the change of pore structure results in better ventilation; second, the relatiouship hetwcen pressure head loss and air flow velocity is nonlinear, and it is beyond the condition of the Iminar flow domain to which Darcy' s law can he applied, when the air flow rate increases to a certain value and the flow velocity is in the transition range to turbulent flow.展开更多
We present a semi-analytic method to study the electronic conductance of a lengthy armchair honeycomb nanoribbon in the presence of vacancies, defects, or impurities located at a small part of it. For this purpose, we...We present a semi-analytic method to study the electronic conductance of a lengthy armchair honeycomb nanoribbon in the presence of vacancies, defects, or impurities located at a small part of it. For this purpose, we employ the Green's function technique within the nearest neighbor tight-binding approach. We first convert the Hamiltonian of an ideal semiinfinite nanoribbon to the Hamiltonian of some independent polyacetylene-like chains. Then, we derive an exact formula for the self-energy of the perturbed part due to the existence of ideal parts. The method gives a fully analytical formalism for some cases such as an infinite ideal nanoribbon and the one including linear symmetric defects. We calculate the transmission coefficient for some different configurations of a nanoribbon with special width including a vacancy, edge geometrical defects, and two electrical impurities.展开更多
This work provides a method to explore the transport property of the electrolyte aqueous solutions with one or two ionic liquids, especially focus on their electrical conductivity. The conductivities were measured for...This work provides a method to explore the transport property of the electrolyte aqueous solutions with one or two ionic liquids, especially focus on their electrical conductivity. The conductivities were measured for the ternary systems Na Cl–[C6mim][Cl](1-hexyl-3-methylimidazolium chloride)–H2O, [C6mim][BF4]–[C6mim][Cl]–H2O,Na NO3–[C6mim][BF4](1-hexyl-3-methylimidazolium tetrafluoroborate)–H2O, and [C4mim][BF4](1-butyl-3-methylimidazolium tetrafluoroborate)–[C6mim][BF4]–H2O, and their binary subsystems NaN O3–H2O, NaC l–H2O,[C6mim][BF4]–H2O, [C6mim][Cl]–H2O, and [C4mim][BF4]–H2O, respectively. The conductivities of the ternary systems were also determined using generalized Young's rule and semi-ideal solution theory in terms of the data of their binary solutions. The comparison showed that the two simple equations provide good predictions for conductivity of mixed electrolyte solutions and the mixed ionic liquid solutions based on the conductivity of their binary subsystems.展开更多
The hydraulic conductivity of saturated clays is commonly determined either directly by monitoring water flux or indirectly based on Terzaghi’s consolidation equation.Similar results are generally obtained from the t...The hydraulic conductivity of saturated clays is commonly determined either directly by monitoring water flux or indirectly based on Terzaghi’s consolidation equation.Similar results are generally obtained from the two methods,but sometimes a significant difference can be observed,in particular for expansive soils.In this study,the hydraulic conductivities determined by the two methods are first compared based on existing data in the literature.The indirect method is then revisited attempting to explain the difference identified.A modified effective stress,considering physico-chemical interaction between face-to-face oriented particles,is finally introduced to better describe the compressibility of expansive clays and to further improve the indirect method in determining hydraulic conductivity of such soils in the low-compressibility zone.Extra tests were performed on Gaomiaozi(GMZ)bentonite slurry and the results obtained allowed the modified indirect method to be verified.展开更多
The Earth’s core is composed of iron,nickel,and a small amount of light elements(e.g.,Si,S,O,C,N,H and P).The thermal conductivities of these components dominate the adiabatic heat flow in the core,which is highly co...The Earth’s core is composed of iron,nickel,and a small amount of light elements(e.g.,Si,S,O,C,N,H and P).The thermal conductivities of these components dominate the adiabatic heat flow in the core,which is highly correlated to geodynamo.Here we review a large number of studies on the electrical and thermal conductivity of iron and iron alloys and discuss their implications on the thermal evolution of the Earth’s core.In summary,we suggest that the Wiedemann-Franz law,commonly used to convert the electrical resistivity to thermal conductivity for metals and alloys,should be cautiously applied under extremely high pressure-temperature(P-T)conditions(e.g.,Earth’s core)because the Lorentz number may be P-T dependent.To date,the discrepancy in the thermal conductivity of iron and iron alloys remains between those from the resistivity measurements and the thermal diffusivity modeling,where the former is systematically larger.Recent studies reconcile the electrical resistivity by first-principles calculation and direct measurements,and this is a good start in resolving this discrepancy.Due to an overall higher thermal conductivity than previously thought,the inner core age is presently constrained at~1.0 Ga.However,light elements in the core would likely lower the thermal conductivity and prolong the crystallization of the inner core.Meanwhile,whether thermal convection can power the dynamo before the inner core formation depends on the amounts of the proper light elements in the core.More works are needed to establish the thermal evolution model of the core.展开更多
基金funded by the Anhui Provincial Natural Science Foundation(Grant No.2008085QE245)the Natural Science Research Project of Higher Education Institutions in Anhui Province(2022AH040045)the Project of Science and Technology Plan of Department of Housing and Urban-Rural Development of Anhui Province(2021-YF22).
文摘The chaotic motion behavior of the rectangular conductive thin plate that is simply supported on four sides by airflow andmechanical external excitation in a magnetic field is studied.According to Kirchhoff’s thin plate theory,considering geometric nonlinearity and using the principle of virtualwork,the nonlinearmotion partial differential equation of the rectangular conductive thin plate is deduced.Using the separate variable method and Galerkin’s method,the system motion partial differential equation is converted into the general equation of the Duffing equation;the Hamilton system is introduced,and the Melnikov function is used to analyze the Hamilton system,and obtain the critical surface for the existence of chaos.The bifurcation diagram,phase portrait,time history response and Poincarémap of the vibration system are obtained by numerical simulation,and the correctness is demonstrated.The results showthatwhen the ratio of external excitation amplitude to damping coefficient is higher than the critical surface,the system will enter chaotic state.The chaotic motion of the rectangular conductive thin plate is affected by different magnetic field distributions and airflow.
文摘American foreign policies have observed guiding principles of democracy, yet an overemphasis on political values leads to more conflicts than mutual understandings in today's world. Therefore, this paper proposes that exploring diplomatic implications of "women's work" provides new insights into cultural values of the Four Freedomsmmajor pillars supporting modern American liberalism. This paper foregrounds the domestic and diplomatic significance of "women's work" by analyzing women's contributions as laborers at home, in the labor force, and in American consumer society. As American women participated in the paid labor force and took up most consumptive activities, women outside America also worked hard to provide food and care for families. This paper argues that a more comprehensive definition of"women's work" is not only indispensable for the development of American industry, consumer society, and the expansion of marketplace, but integrates a system of dualisms separating wage labor and housework, or divisions between spheres of men and women. Moreover, investigations into hidden values of women's work alleviate worries arising from information revolution and economic globalization. Moreover, placing women's work in perspective enables diplomats to see through factors leading to international hostilities, to reduce conflicts arising from information revolution and economic globalization, and to understand America's soft power pertinently.
文摘With the development of network technology and information technology, electronic commerce as a new business model wiht itsnew trading ideas-+, In changing the traditional business structure,but also gradually changing people’s shopping patterns and consumptionpatterns,Online shopping has become the preferred way of shopping.Changes in consumption patterns will inevitably lead to new problems inthe process of consumption,and the development speed of the problem in sync with the development speed of network economy,as far as therenewal speed of laws and regulations is concerned,this asymmetric development is bound to bring great inconvenience to the consumer rights innetwork transactions.In this paper, from the angle of legal protection,the protection of consumer rights and interests in network transactions areexpounded,analysis of the current situation and reasons of the consumers’ rights and interests are infringed upon in the network transaction,learnfrom the experience of foreign consumer rights and interests protection,In order to put forward effective suggestions on the system constructionof the protection of consumer rights and interests.
文摘The Professor's House presents the readers pictures with striking consumer culture characteristics. With abundant goods of sign values, conspicuous consumption, swelling-desire-stimulating power and the individuals' efforts to construct their identities through consumption as dominant features, consumer culture exerts negative and even devastating effects on the characters in the novel. Theories of ecocriticism shed new lights on the interpretation of consumerism reflected in the novel, especially on analyzing how the consumer culture makes the characters suffer from split personality, alienation from nature, society, and even from themselves and their spiritual ecology.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51137004,51277169,and 61271424)
文摘Conductivities tomography with the interactions of magnetic field, electrical field, and ultrasound field is presented in this paper. We utilize a beam of ultrasound in scanning mode instead of the traditional ultrasound field generated by point source. Many formulae for the reconstruction of conductivities are derived from the voltage signals detected by two electrodes arranged somewhere on tissue's surface. In a forward problem, the numerical solutions of ultrasound fields generated by the piston transducer are calculated using the angular spectrum method and its Green's function is designed approximately in far fields. In an inverse problems, the magneto-acousto-electrical voltage signals are proved to satisfy the wave equations if the voltage signals are extended to the whole region from the boundary locations of transducers. Thus the time-reversal method is applied to reconstructing the curl of the reciprocal current density. In addition, a least square iteration method of recovering conductivities from reciprocal current densities is discussed.
基金This work was supported by the National Natural Science Foundation of China (No. 41274110), and the Northeast Petroleum University Innovation Foundation for Postgraduate (No. YJSCX2016-003NEPU).
文摘The conductance of pyrite-bearing laminated and dispersed shaly sands is not well understood and resistivity models for pyrite-bearing shaly sands are nonexistent. Thus, we first synthesize clean pyrite-matrix samples, and quartz-matrix samples with variable laminated shale, dispersed shale, and pyrite content and then perform petrophysics experiments to assess the effect of pyrite content on the conductivity of pyrite-bearing shaly sands. Second, based on the differences in conductivity and conduction pathways and geometries because of the variable composition of the pyrite-bearing laminated and dispersed shaly sands, we divide the shaly sands into their components, i.e., laminated shale, quartz grains, pyrite grains, hydrocarbon, dispersed shale, microscopic capillary water, and mobile water. A generalized resistivity model is proposed to describe the conductivity of pyrite- bearing laminated and dispersed shaly sands, based on the combined conductivity differential equation and generalized Archie equation. In the generalized resistivity model, the conductivity differential equation is used to describe the conductivity of dispersed inclusions in a host, whereas the generalized Archie equation is used to describe the conductivity of two conducting phases. Moreover, parallel conductance theory is used to describe the conductivity of dispersed shaly sands and laminated shale. Theoretical analysis suggests that the proposed model satisfies the physical constraints and the model and experimental results agree. The resistivity and resistivity index of shaly sands decrease with increasing conductivity and pyrite. Finally, the accuracy of the resistivity model is assessed based on experimental data from 46 synthetic core samples with different oil saturation. The model can describe the conductivity of clean pyrite-matrix samples, and quartz-matrix samples with different volumes of laminated shale, dispersed shale, and pyrite. An accurate saturation model of pyrite-bearing laminated and dispersed shaly sands is thus obtained and the log data interpretation in complex shaly sands can improve with the proposed model.
文摘Five kinds of molybdovanadophosphoric acids H_7[P_2Mo_(17)VO_(62)],H_8[P_2Mo_(16)·V_2O_(62)],H_9 [P_2Mo_(15)V_3O_(62)],H_8[P_2Mo_(14)V_4O_(61)(H_2O)]and H_9[P_2Mo_(13)V_5O_(61)(H_2O)]have been synthesized.Their protop conductivities(C) have been measured.The effects of three main factors (frequency,hydration numbers,temperature)on the conductivity have been investigated.In some degree,heteropoly compounds with different structures give a different conductivity.
基金Supported by the Innovation and Technology Fund of Hong Kong, China
文摘AIM: To investigate the effect of tetramethylpyrazine (TMP), an active compound from Ligustium Wollichii Franchat, on electrolyte transport across the distal colon of rodents and the mechanism involved.METHODS: The short-circuit current (Isc) technique in conjunction with pharmacological agents and specific inhibitors were used in analyzing the electrolyte transport across the distal colon of rodents. The underlying cellular signaling mechanism was investigated by radioimmunoassay analysis (RIA) and a special mouse model of cystic fibrosis.RESULTS: IMP stimulated a conoentration-dependent rise in ISCl, which was dependent on both Cl^- and HCO3^-, and inhibited by apical application of diphenylamine-2,2'-dicarboxylic acid (DPC) and glibenclamide, but resistant to 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid disodium salt hydrate (DIDS). Removal of Na^+ from basolateral solution almost completely abolished the Isc response to TMP, but it was insensitive to apical Na^+ replacement or apical Na^+ channel blocker, amiloride. Pretreatment of colonic mucosa with BAPTA-AM, a membrane-permeable selective Ca2+ chelator, did not significantly alter the TMP-induced Iso No additive effect of forskolin and 3-isobutyl-l-methylxanthine ([BMX) was observed on the TMP-induced Isc, but it was significantly reduced by a protein kinase A inhibitor, H89.RIA results showed that TMP (1 mmol/L) elicited a significant increase in cellular cAMP production, which was similar to that elicited by the adenylate cyclase activator, forskolin (10μmol/L). The TMP-elicited Isc as well as forskolin- or IBMX-induced Isc were abolished in mice with homozygous mutation of the cystic fibrosis transmembrane conductance regulator (CFTR) presenting defective CFTR functions and secretions.CONCLUSION: TMP may stimulate cAMP-dependent and CFTR-mediated Cl^- and HCO3^- secretion. This may have implications in the future development of alternative treatment for constipation.
文摘A series of aluminium-containing α-type hydrated zirconium hydrogen phosphates,Zr_(1-x)Alx (H_(1+x/2)PO_4 )_2 with x=0-0.06,were hydrothermally synthesized and characterizedby means of X-ray diffraction,differential thermal analysis and thermogravimetric analysis.The proton conductivity,1.2×10 ̄(-4) S·cm ̄(-1)at 180℃ was found in Zr_(0.98)Al_(0.02)(H_(1.01)PO_4)_2·H_2O.Humidity-sensing measurements were carried out at 120℃ and 140℃ respectively.Even a limited substitution of Al for Zr can enhance both proton conductivity and humidity sensitivity.
基金financially supported by the National Natural Science Foundation of China(52074113,22005091,and 22005092)the Hunan University Outstanding Youth Science Foundation(531118040319)+5 种基金the Science and Technology Innovation Program of Hunan Province(2021RC3055)the Changsha Municipal Natural Science Foundation(kq2014037)the CITIC Metals Ningbo Energy Co.Ltd.(H202191380246)the Chongqing Talents:Exceptional Young Talents Project(CQYC202105015)the Shenzhen Virtual University Park Basic Research Project of Free exploration(2021Szvup036)financially supported by the Graduate Research and Innovation Projects of Hunan Province(QL20210088)。
文摘Lithium metal has gained extensive attention as the most ideal candidate for next-generation battery anode owing to the ultrahigh specific capacity and the lowest electrochemical potential.However,uncontrollable dendrite growth and huge volume variation extremely restrict the future deployment of lithium metal batteries.Herein,we report metal chalcogenide SnSSe with unique nanoplate stacking structure as a robust substrate for stable Li metal anode.During the initial Li plating process,lithiophilic Li_(22)Sn_(5) alloy and Li_(2)S/Li_(2)Se sites are obtained via in-situ electrochemical reaction of Li metal and SnSSe.Density functional theory(DFT)calculation demonstrates that the formed Li_(2)S/Li_(2)Se achieves low Li diffusion energy barrier,ensuring rapid Li~+migration.Li_(22)Sn_(5) alloy provides strong nucleation sites,promoting uniform Li nucleation.Furthermore,in-situ optical microscopy analysis suggests that the synthesized effect fundamentally inhibits lithium dendrite growth.Consequently,SnSSe modified Cu foil delivered an ultralow nucleation overpotential,superior cycling stability with 450 cycles(Coulombic efficiency,>98%),and excellent plating/stripping behavior over 2200 h at 0.5 mA cm^(-2).Moreover,the brilliant reversible cycles and rate capability were also realized in Li@SnSSe//LiFePO_(4)(LFP)full cell,shedding light on the feasibility of SnSSe for stable and dendrite-free lithium metal anode.
基金This paper is supported by the National Natural Science Foundation ofChina(No.40272107)and the Key Research Fund of Ministry of Edu-cation of China(No.104012).
文摘To study the variation pattern of aero conductivity of different porous media under low pressure conditions, three kinds of media are selected. These include sandy clay loam, fine sand, and medium sand, and air us fluid to conduct soil column ventilation tests. Pressure at both ends of the colruns is measured under different ventilation flow rates during testing. The test results show that the aero conductivity, solved by Darcy's law, is not a coustant. It is a variable, which increases first when air flow velocity is less than 0. 258 7 cm/s for sandy clay loam, 0. 637 3 cm/s for fine sand and then decreases when air flow velocity is bigger than that with the increase of the ventilation flow rate when the medium is determined. By analyzing various factors that influence the flow resistance, the reasons for variation in aero conductivity are found us follows: first, the change of pore structure results in better ventilation; second, the relatiouship hetwcen pressure head loss and air flow velocity is nonlinear, and it is beyond the condition of the Iminar flow domain to which Darcy' s law can he applied, when the air flow rate increases to a certain value and the flow velocity is in the transition range to turbulent flow.
文摘We present a semi-analytic method to study the electronic conductance of a lengthy armchair honeycomb nanoribbon in the presence of vacancies, defects, or impurities located at a small part of it. For this purpose, we employ the Green's function technique within the nearest neighbor tight-binding approach. We first convert the Hamiltonian of an ideal semiinfinite nanoribbon to the Hamiltonian of some independent polyacetylene-like chains. Then, we derive an exact formula for the self-energy of the perturbed part due to the existence of ideal parts. The method gives a fully analytical formalism for some cases such as an infinite ideal nanoribbon and the one including linear symmetric defects. We calculate the transmission coefficient for some different configurations of a nanoribbon with special width including a vacancy, edge geometrical defects, and two electrical impurities.
基金Supported by the National Natural Science Foundation of China(51066004)the Scientific Research Project of Higher Education Institutions of Inner Mongolia(NJZY14172)the Innovation Fund of Inner Mongolia Science and Technology(2011NCL060)
文摘This work provides a method to explore the transport property of the electrolyte aqueous solutions with one or two ionic liquids, especially focus on their electrical conductivity. The conductivities were measured for the ternary systems Na Cl–[C6mim][Cl](1-hexyl-3-methylimidazolium chloride)–H2O, [C6mim][BF4]–[C6mim][Cl]–H2O,Na NO3–[C6mim][BF4](1-hexyl-3-methylimidazolium tetrafluoroborate)–H2O, and [C4mim][BF4](1-butyl-3-methylimidazolium tetrafluoroborate)–[C6mim][BF4]–H2O, and their binary subsystems NaN O3–H2O, NaC l–H2O,[C6mim][BF4]–H2O, [C6mim][Cl]–H2O, and [C4mim][BF4]–H2O, respectively. The conductivities of the ternary systems were also determined using generalized Young's rule and semi-ideal solution theory in terms of the data of their binary solutions. The comparison showed that the two simple equations provide good predictions for conductivity of mixed electrolyte solutions and the mixed ionic liquid solutions based on the conductivity of their binary subsystems.
基金support of the European Commission by the Marie Sk1odowska-Curie Actions HERCULES Towards Geohazards Resilient Infrastructure Under Changing Climates(Grant No.H2020-MSCA-RISE-2017-778360)Shanghai Pujiang Talent Program(Grant No.18PJ1410200)。
文摘The hydraulic conductivity of saturated clays is commonly determined either directly by monitoring water flux or indirectly based on Terzaghi’s consolidation equation.Similar results are generally obtained from the two methods,but sometimes a significant difference can be observed,in particular for expansive soils.In this study,the hydraulic conductivities determined by the two methods are first compared based on existing data in the literature.The indirect method is then revisited attempting to explain the difference identified.A modified effective stress,considering physico-chemical interaction between face-to-face oriented particles,is finally introduced to better describe the compressibility of expansive clays and to further improve the indirect method in determining hydraulic conductivity of such soils in the low-compressibility zone.Extra tests were performed on Gaomiaozi(GMZ)bentonite slurry and the results obtained allowed the modified indirect method to be verified.
基金financial support from the National Natural Science Foundation of China(Grant Nos.41804082 and 41873073)the Special Research Assistant Funding Program provided by the Chinese Academy of Sciences。
文摘The Earth’s core is composed of iron,nickel,and a small amount of light elements(e.g.,Si,S,O,C,N,H and P).The thermal conductivities of these components dominate the adiabatic heat flow in the core,which is highly correlated to geodynamo.Here we review a large number of studies on the electrical and thermal conductivity of iron and iron alloys and discuss their implications on the thermal evolution of the Earth’s core.In summary,we suggest that the Wiedemann-Franz law,commonly used to convert the electrical resistivity to thermal conductivity for metals and alloys,should be cautiously applied under extremely high pressure-temperature(P-T)conditions(e.g.,Earth’s core)because the Lorentz number may be P-T dependent.To date,the discrepancy in the thermal conductivity of iron and iron alloys remains between those from the resistivity measurements and the thermal diffusivity modeling,where the former is systematically larger.Recent studies reconcile the electrical resistivity by first-principles calculation and direct measurements,and this is a good start in resolving this discrepancy.Due to an overall higher thermal conductivity than previously thought,the inner core age is presently constrained at~1.0 Ga.However,light elements in the core would likely lower the thermal conductivity and prolong the crystallization of the inner core.Meanwhile,whether thermal convection can power the dynamo before the inner core formation depends on the amounts of the proper light elements in the core.More works are needed to establish the thermal evolution model of the core.