N-(4-Carboxy-phenyl)-3,5-di-t-butyl-4-hydroxy-benzamide (2) possesses structural prerequisite for cell differentiation inducing activity, which constitutes the therapeutic basis of all trans retinoic acid (ATRA) ...N-(4-Carboxy-phenyl)-3,5-di-t-butyl-4-hydroxy-benzamide (2) possesses structural prerequisite for cell differentiation inducing activity, which constitutes the therapeutic basis of all trans retinoic acid (ATRA) and analogues for the treatment of cancer and dermatosis. In addition to the similarity of the disposition of functional groups with ATRA, 2 shows a conformational equivalence to ATRA in terms of molecular shape, size, as well as the spatial arrangement of functional groups. However, the N methylated compound (3) is devoid of the activity. It owes the biological behavior to the conformational difference, because of the steric interference between N methyl group and the hydrogen atom of a phenyl ring. X ray crystallography, UV, and NMR were performed to investigate the difference.展开更多
A systematic analysis of the polymeric Mach-Zehnder rib waveguide is presented based on the calculation and optimization. The simulation is carried out with the Effective Index Method (EIM) and two-dimensional (2-D) F...A systematic analysis of the polymeric Mach-Zehnder rib waveguide is presented based on the calculation and optimization. The simulation is carried out with the Effective Index Method (EIM) and two-dimensional (2-D) Finite Difference Beam Propagation Method (FD-BPM). The large refractive index step between the consecutive polymer layers is reduced by using EIM and thus the precision of the calculation is ensured. The important param- eters of the waveguide such as Y-junction angle and the separation gap are discussed and their relationships with the optical power propagation and the loss characteristics are investigated in this paper. The total loss of the opti- mized structure is 0.258 dB.展开更多
Using ethylene glycol as solvent and reductant, CuCl2-2H2O, (NH2)2CS and self-prepared GaCl3 as the starting materials, CuGaS2 nanostrucutures were synthesized on a large scale at 220℃. Powder X-ray diffraction. tr...Using ethylene glycol as solvent and reductant, CuCl2-2H2O, (NH2)2CS and self-prepared GaCl3 as the starting materials, CuGaS2 nanostrucutures were synthesized on a large scale at 220℃. Powder X-ray diffraction. transmission electron microscopy, field-emission scanning electron microscope, high-resolution transmission electron microscopy" and X-ray" photoelectron spectroscopy were used to characterize the products. It demonstrated the evolution of the CuGaS2 particles from spherical assemblies to flowerlike morphology, over time, at 220℃. Simultaneously, we elucidated the specific roles of reaction temperature, reaction time and solvent in the formation of the final CuGaS2 nanostructures. A possible formation mechanism of CuGaS2 nanostrucutures was also discussed. The room temperature photoluminescence spectrum showed blue-shift and an increase of intensity, with a decrease in the sizes of CuGaS2 particles.展开更多
Nanoparticles of pure and Cu/Ag-doped CdS and ZnS have been synthesized via chemical bath deposition without using any capping or toxic reagents.The synthesis was carried out through a simple and less expensive green ...Nanoparticles of pure and Cu/Ag-doped CdS and ZnS have been synthesized via chemical bath deposition without using any capping or toxic reagents.The synthesis was carried out through a simple and less expensive green method.The XRD result shows that both pure CdS and ZnS and their doped derivatives are of high crystalline with hexagonal packing structure.The average crystalline size of all nanoparticles was calculated using Debye-Scherrer formula.The crystalline size of nanoparticles of pure samples varied with that of the doped sample.The average crystalline sizes of all nanoparticles are found to be in the range of 5.5-2.2 nm for CdS(from pure to doped) and 4.3-3.4 nm for ZnS,respectively.The band gap values obtained from UV-visible spectra are in the range of 3.5-2.1 e V for CdS and 3.3-2.7 e V for ZnS derivatives,respectively.The FTIR spectral data give characteristic peaks for Cd—S,Cu—S,Ag—S and Zn—S bonds and confirm the formation of respective nanoparticles.The peaks corresponding to the microstructural formation are also observed.The FE-SEM images show the granular morphological structure for all the samples.The agglomeration size of the samples in the range of 10-50 nm for CdS:Cu and 50-100 nm for ZnS:Cu is observed.展开更多
Photocatalysis driven by near-infrared(NIR)light is of scientific and technological interest for ex-ploiting solar energy.In this study,we demonstrate a facile hydrothermal process to synthesize core-shell nanoparti...Photocatalysis driven by near-infrared(NIR)light is of scientific and technological interest for ex-ploiting solar energy.In this study,we demonstrate a facile hydrothermal process to synthesize core-shell nanoparticles combining upconversion nanoparticles(UCNPs)and alloyed ZnxCwhich can be excited using NIR or visible light.Morphologies,phase,and chemical composition have been investigated using field-emission scanning electron microscopy,transmission electron mi-croscopy,X-ray diffraction analysis,and atomic absorption spectroscopy.Moreover,we found that amorphous TiO2 layers existing in the final samples play an important role in formation ofyolk-shell nanoparticles,which bind the as-prepared ZnxCnanoparticlescan be tuna-ble by adjusting the amount of the Cd and Zn source compounds.The photochemical reduction of Cr(Ⅵ)in water has been performed to study the photocatalytic performance under irradiation by NIR light or a simulated solar light,showing efficient photoreduction and Cr(Ⅵ)removal over the/TiO2 yolk-shell nanoparticles.The as-prepared UCNPs@ZnxC/TiO2 nanoparticles show excellent production of hydroxyl radicals,which are responsible for the photochemical reduction of Cr(Ⅵ)to Cr(Ⅲ).This study will provide an alternative strategy for en-vironmental wastewater treatment,making full use of solar energy.展开更多
By varying concentration of PEG1000 as a structure-directing agent,mesoporous alumina with excellent textural properties was synthesized.The prepared mesoporous alumina displays high thermal stability,as shown by its ...By varying concentration of PEG1000 as a structure-directing agent,mesoporous alumina with excellent textural properties was synthesized.The prepared mesoporous alumina displays high thermal stability,as shown by its textural properties at different calcination temperatures of 600-850 °C.Characterization by SEM and TEM revealed that the added PEG surfactant induced the formation of petal-like alumina.XRD results clarified that all samples were amorphous and their peaks were around the peaks of γ-alumina.N_2 adsorption-desorption analysis showed that the prepared mesoporous alumina,if with PEG1000 in hydrolysis of aluminum isopropoxide,had excellent textural properties with large specific surface area,high pore volume and suitable pore size.The petal-like structure existing in the alumina samples improved their textural parameters,and the role and influential mechanism of PEG1000 were analyzed.展开更多
Ion conductive membranes(ICMs)are frequently used as separators for energy conversion and storage technologies of fuel cells,flow battery,and hydrogen pump,because of their good ion-selective conduction and low electr...Ion conductive membranes(ICMs)are frequently used as separators for energy conversion and storage technologies of fuel cells,flow battery,and hydrogen pump,because of their good ion-selective conduction and low electronic conductivity.Firstly,this feature article reviews the recent studies on the development of new nonfluorinated ICMs with low cost and their macro/micro-structure control.In general,these new nonfluorinated ICMs have lower conductivity than commercial perfluorinated ones,due to their poor ion transport channels.Increasing ion exchange capacity(IEC)would create more continuous hydrophilic channels,thus enhancing the conductivity.However,high IEC also expands the overall hydrophilic domains,weakens the interaction between polymer chains,enhances the mobility of polymer chains,and eventually induces larger swelling.The micro-scale expansion and macro-scale swelling of the ICMs with high IEC could be controlled by limiting the mobility of polymer chains.Based on this strategy,some ef ficient techniques have been developed,including covalent crosslinking,semi-interpenatrating polymer network,and blending.Secondly,this review introduces the optimization of macro/microstructure of both perfluorinated and nonfluorinated ICMs to improve the performance.Macro-scale multilayer composite is an ef ficient way to enhance the mechanical strength and the dimensional stability of the ICMs,and could also decrease the content of per fluorosulfonic acid resin in the membrane,thereby reducing the cost of the perfluorinated ICMs.Long side chain,multiple functionalization,small molecule inducing micro-phase separation,electrospun nano fiber,and organic–inorganic hybrid could construct more ef ficient ion transport channels,improving the ion conductivity of ICMs.展开更多
A theoretical basis of optimally designed BRAQWET is pr esented. The optimum parameters of MgZnSSe/ZnSe BRAQWET are obtained by the ca lculation of band-structure according to the depletion approximation.
The solvo―thermal technique is used for the synthesis of [Mn(en)_3]Te_4 (I).The crystal structure has been determined by single crystal X―ray diffraction techniques. Thecrystal belongs to the monoclinic, space group...The solvo―thermal technique is used for the synthesis of [Mn(en)_3]Te_4 (I).The crystal structure has been determined by single crystal X―ray diffraction techniques. Thecrystal belongs to the monoclinic, space group p2_1/c with unit cell:a = 0. 846 1(1), b=1.5653(2),c=1.426 9(2) nm, α = 90°, β=91. 37(1) (3)°, γ=90°, V=1. 889 3(4) nm^3, and Z=4. The resultsshow that the structure contains a linear chain Zintl anion, [Te_4 ]^(2-) and a complex cation,[Mn(en)_3l^(2+). Optical studies have been performed on the powder sample of I, suggesting that thecompound is a semiconductor with a band gap of 0. 73 eV. The semiconductor properties for MnQ_2(Q=S, Se, Te) and [Mn(en)_3]Te_4 have been discussed by molecular orbital theory.展开更多
Background The mitochondrial Na^+/Ca^2+ exchanger, NCLX, plays an important role in the balance between Ca2. influx and efflux across the mitochondrial inner membrane in endothelial ceils. Mitochondrial metabolism i...Background The mitochondrial Na^+/Ca^2+ exchanger, NCLX, plays an important role in the balance between Ca2. influx and efflux across the mitochondrial inner membrane in endothelial ceils. Mitochondrial metabolism is likely to be affected by the activity of NCLX because Ca^2+ activates several enzymes of the Krebs cycle. It is currently believed that mitochondria are not only centers of energy produc- tion but are also important sites of reactive oxygen species (ROS) generation and nucleotide-binding oligomerization domain receptor 3 (NLRP3) inflammasome activation. Methods & Results This study focused on NCLX function, in rat aortic endothelial cells (RAECs), induced by glucose. First, we detected an increase in NCLX expression in the endothelia of rats with diabetes mellitus, which was induced by an injection of streptozotocin. Next, colocalization of NCLX expression and mitochondria was detected using confocal analysis. Suppression of NCLX expression, using an siRNA construct (siNCLX), enhanced mitochondrial Ca^2+ influx and blocked efflux induced by glucose. Unexpectedly, silencing of NCLX expression induced increased ROS generation and NLRP3 inflammasome activation. Conclusions These findings suggest that NCLX affects glucose-dependent mitochondrial Ca^2+ signaling, thereby regulating ROS generation and NLRP3 in- flammasome activation in high glucose conditions. In the early stages of high glucose stimulation, NCLX expression increases to compensate in order to self-protect mitochondrial maintenance, stability, and function in endothelial cells.展开更多
Aluminum doped hydroxyapatite (HA:AI3 +) nanopowders were successfully prepared via a simple and efficient one-pot mechanochemical route. The effects of dopant loading on phase compositions and structural features...Aluminum doped hydroxyapatite (HA:AI3 +) nanopowders were successfully prepared via a simple and efficient one-pot mechanochemical route. The effects of dopant loading on phase compositions and structural features were assessed by Rietveld analysis. The XRD-Rietveld refinement revealed the stabilization of HA in hexagonal structure for all the samples. The sharpness and intensity of the apatite-derived XRD peaks decreased as the dopant content increased to 10% due to the increase in lattice imperfections and mechanically induced amorphization. The incorpo- ration of A13 + into the HA lattice decreased the unit cell parameters. From the FfiR measurements, the representing bands of apatite were identified in all cases. The mechanosynthesized nanopowders consisted of nanospheroids with an average size of 44 - 20 nm and therefore are promising for bone tissue regeneration.展开更多
Ni-Ce0.8Sm.2O.9 (Ni-SDC) cermet was selected as anode material for reduced temperature (800℃) solid oxide fuel cells in this study. The influence of NiO powder fabrication methods for Ni-SDC cermets on the electr...Ni-Ce0.8Sm.2O.9 (Ni-SDC) cermet was selected as anode material for reduced temperature (800℃) solid oxide fuel cells in this study. The influence of NiO powder fabrication methods for Ni-SDC cermets on the electrode performance was investigated so that the result obtained can be applied to make high-quality anode. Three kinds of NiO powder were synthesized with a fourth kind being available in the market. Four types of anode precursors were fabricated with these NiO powders and Ce0.8Sm.2O.9 (SDC), and then were reduced to anode wafers for sequencing measurement. The electrical conductivity of the anodes was measured and the effect ofmicrostructure was investigated. It was found that the anode electrical conductivity depends strongly on the NiO powder morphologies, microstructure of the cermet anode and particle sizes, which are decided by NiO powder preparation technique. The highest electrical conductivity is obtained for anode cermets with NiO powder synthesized by NiCO3-2Ni(OH)2-4H2O or Ni(NO3)2-6H2O decomposition technique.展开更多
Grooved gate structure Metal-Oxide-Semiconductor (MOS) device is consideredas the most promising candidate used in deep and super-deep sub-micron region, for it cansuppress hot carrier effect and short channel effect ...Grooved gate structure Metal-Oxide-Semiconductor (MOS) device is consideredas the most promising candidate used in deep and super-deep sub-micron region, for it cansuppress hot carrier effect and short channel effect deeply. Based on the hydrodynamic energytransport model, using two-dimensional device simulator Medici, the relation between structureparameters and hot carrier effect immunity for deep-sub-micron N-channel MOSFET's is studiedand compared with that of counterpart conventional planar device in this paper. The examinedstructure parameters include negative junction depth, concave corner and effective channel length.Simulation results show that grooved gate device can suppress hot carrier effect deeply even indeep sub-micron region. The studies also indicate that hot carrier effect is strongly influencedby the concave corner and channel length for grooved gate device. With the increase of concavecorner, the hot carrier effect in grooved gate MOSFET decreases sharply, and with the reducingof effective channel length, the hot carrier effect becomes large.展开更多
As global issues become more prominent and complex, various actors in the international community are strengthening global governance through systems of international cooperation. Different international actors have d...As global issues become more prominent and complex, various actors in the international community are strengthening global governance through systems of international cooperation. Different international actors have different identities, responsibilities and roles in international institutions due to their comprehensive strengths. They are roughly divided into three types: followers, supporters and leaders. Since the founding of the People's Republic of China in 1949, its process of participation in international institutions and global governance has been obviously staged.In recent years, China has actively participated in various major international activities and carried out a series of diplomatic activities at home, which further demonstrates its involvement from a single participant to both a leader and a participant. In the existing traditional, modified and innovative international institutions, China is essentially playing a dual role, namely the roles of participant and supporter, the supporter and reformer, and the supporter and leader.展开更多
MBE growth of ZnS_xSe_1-x thin films on ITO coated glass substrate s were carried o ut using ZnS and Se sources with the substrate temperature ranging from 270℃ to 330℃. The XRD θ/2θ spectra resulted from these...MBE growth of ZnS_xSe_1-x thin films on ITO coated glass substrate s were carried o ut using ZnS and Se sources with the substrate temperature ranging from 270℃ to 330℃. The XRD θ/2θ spectra resulted from these films indicated that the as-gro wn polycrystalline ZnS_xSe_1-x thin films had a preferred orientat ion along the (1 11) planes. The evaluated crystal sizes as deduced from the FWHM of the XRD laye r peaks showed strong growth temperature dependence, with the optimized temperat ure being about 290℃. Both AFM and TEM measurements of these thin films also in dicated a similar growth temperature dependence. High quality ZnS_xSe_1- x thin fil m grown at the optimized temperature had the smoothest surface with lowest RMS v alue of 1.2 nm and TEM cross-sectional micrograph showing a well defined column ar structure.展开更多
Solid sorbents adsorption is considered as one of the potential options for CO2 capture process. CO2 adsorption on MCM-68 (Si/AI ratio 22) sorbent material was investigated. MCM-68 was synthesized using N,N,N',N'-...Solid sorbents adsorption is considered as one of the potential options for CO2 capture process. CO2 adsorption on MCM-68 (Si/AI ratio 22) sorbent material was investigated. MCM-68 was synthesized using N,N,N',N'-tetraethylbicyclo [2.2.2] oct-7-ene-2,3:5,6-dipyrrolidinium diiodide (TEBOP^2+(I^+)2) as a structure-directing agent (SDA). CO2 adsorption capacity on MCM-68 sorbent was measured at a broad temperature window i.e. 60 ℃, 300 ℃ and at 400 ℃. The presence of ordered mesoporous structure, high surface area (456 me/g) and high thermal stability (TGA analysis up to 900℃) in MCM-68 are thought to be to be advantageous for the CO2 adsorption in broad temperature window.展开更多
Organic polymer solar cells (OSCs) and organic-inorganic hybrid perovskite solar cells (PSCs) have achieved notable progress over the past several years. A central topic in these fields is exploring electronically...Organic polymer solar cells (OSCs) and organic-inorganic hybrid perovskite solar cells (PSCs) have achieved notable progress over the past several years. A central topic in these fields is exploring electronically efficient, stable and effective hole-transporting layer (HTL) materials. The goal is to enhance hole-collection ability, reduce charge recombination, increase built-in voltage, and hence improve the performance as well as the device stability. Transition metal oxides (TMOs) semiconductors such as NiOx, CuOx, CrOx, MoOx, WO3, and V2O5, have been widely used as HTLs in OSCs. These TMOs are naturally adopted into PSC as HTLs and shows their importance. There are similarities, and also differences in applying TMOs in these two types of main solution processed solar cells. This concise review is on the recent developments of transition metal oxide HTL in OSCs and PSCs. The paper starts from the discussion of the cation valence and electronic structure of the transition metal oxide materials, followed by analyzing the structure-property relationships of these HTLs, which we attempt to give a systematic introduction about the influences of their cation valence, electronic structure, work ftmction and film property on device performance.展开更多
文摘N-(4-Carboxy-phenyl)-3,5-di-t-butyl-4-hydroxy-benzamide (2) possesses structural prerequisite for cell differentiation inducing activity, which constitutes the therapeutic basis of all trans retinoic acid (ATRA) and analogues for the treatment of cancer and dermatosis. In addition to the similarity of the disposition of functional groups with ATRA, 2 shows a conformational equivalence to ATRA in terms of molecular shape, size, as well as the spatial arrangement of functional groups. However, the N methylated compound (3) is devoid of the activity. It owes the biological behavior to the conformational difference, because of the steric interference between N methyl group and the hydrogen atom of a phenyl ring. X ray crystallography, UV, and NMR were performed to investigate the difference.
基金the foundation for Advance ResearchProgram of Weapon Equipment, China (Grant No.02040105DZ02).
文摘A systematic analysis of the polymeric Mach-Zehnder rib waveguide is presented based on the calculation and optimization. The simulation is carried out with the Effective Index Method (EIM) and two-dimensional (2-D) Finite Difference Beam Propagation Method (FD-BPM). The large refractive index step between the consecutive polymer layers is reduced by using EIM and thus the precision of the calculation is ensured. The important param- eters of the waveguide such as Y-junction angle and the separation gap are discussed and their relationships with the optical power propagation and the loss characteristics are investigated in this paper. The total loss of the opti- mized structure is 0.258 dB.
文摘Using ethylene glycol as solvent and reductant, CuCl2-2H2O, (NH2)2CS and self-prepared GaCl3 as the starting materials, CuGaS2 nanostrucutures were synthesized on a large scale at 220℃. Powder X-ray diffraction. transmission electron microscopy, field-emission scanning electron microscope, high-resolution transmission electron microscopy" and X-ray" photoelectron spectroscopy were used to characterize the products. It demonstrated the evolution of the CuGaS2 particles from spherical assemblies to flowerlike morphology, over time, at 220℃. Simultaneously, we elucidated the specific roles of reaction temperature, reaction time and solvent in the formation of the final CuGaS2 nanostructures. A possible formation mechanism of CuGaS2 nanostrucutures was also discussed. The room temperature photoluminescence spectrum showed blue-shift and an increase of intensity, with a decrease in the sizes of CuGaS2 particles.
文摘Nanoparticles of pure and Cu/Ag-doped CdS and ZnS have been synthesized via chemical bath deposition without using any capping or toxic reagents.The synthesis was carried out through a simple and less expensive green method.The XRD result shows that both pure CdS and ZnS and their doped derivatives are of high crystalline with hexagonal packing structure.The average crystalline size of all nanoparticles was calculated using Debye-Scherrer formula.The crystalline size of nanoparticles of pure samples varied with that of the doped sample.The average crystalline sizes of all nanoparticles are found to be in the range of 5.5-2.2 nm for CdS(from pure to doped) and 4.3-3.4 nm for ZnS,respectively.The band gap values obtained from UV-visible spectra are in the range of 3.5-2.1 e V for CdS and 3.3-2.7 e V for ZnS derivatives,respectively.The FTIR spectral data give characteristic peaks for Cd—S,Cu—S,Ag—S and Zn—S bonds and confirm the formation of respective nanoparticles.The peaks corresponding to the microstructural formation are also observed.The FE-SEM images show the granular morphological structure for all the samples.The agglomeration size of the samples in the range of 10-50 nm for CdS:Cu and 50-100 nm for ZnS:Cu is observed.
基金supported by the National Natural Science Foundation of China (21471043, 51603059, 31501576)~~
文摘Photocatalysis driven by near-infrared(NIR)light is of scientific and technological interest for ex-ploiting solar energy.In this study,we demonstrate a facile hydrothermal process to synthesize core-shell nanoparticles combining upconversion nanoparticles(UCNPs)and alloyed ZnxCwhich can be excited using NIR or visible light.Morphologies,phase,and chemical composition have been investigated using field-emission scanning electron microscopy,transmission electron mi-croscopy,X-ray diffraction analysis,and atomic absorption spectroscopy.Moreover,we found that amorphous TiO2 layers existing in the final samples play an important role in formation ofyolk-shell nanoparticles,which bind the as-prepared ZnxCnanoparticlescan be tuna-ble by adjusting the amount of the Cd and Zn source compounds.The photochemical reduction of Cr(Ⅵ)in water has been performed to study the photocatalytic performance under irradiation by NIR light or a simulated solar light,showing efficient photoreduction and Cr(Ⅵ)removal over the/TiO2 yolk-shell nanoparticles.The as-prepared UCNPs@ZnxC/TiO2 nanoparticles show excellent production of hydroxyl radicals,which are responsible for the photochemical reduction of Cr(Ⅵ)to Cr(Ⅲ).This study will provide an alternative strategy for en-vironmental wastewater treatment,making full use of solar energy.
基金Supported by the National Basic Research Program of China(Y419012198)the National Natural Science Foundation of China(No.91534125)
文摘By varying concentration of PEG1000 as a structure-directing agent,mesoporous alumina with excellent textural properties was synthesized.The prepared mesoporous alumina displays high thermal stability,as shown by its textural properties at different calcination temperatures of 600-850 °C.Characterization by SEM and TEM revealed that the added PEG surfactant induced the formation of petal-like alumina.XRD results clarified that all samples were amorphous and their peaks were around the peaks of γ-alumina.N_2 adsorption-desorption analysis showed that the prepared mesoporous alumina,if with PEG1000 in hydrolysis of aluminum isopropoxide,had excellent textural properties with large specific surface area,high pore volume and suitable pore size.The petal-like structure existing in the alumina samples improved their textural parameters,and the role and influential mechanism of PEG1000 were analyzed.
基金Supported by the National Science Fund for Distinguished Young Scholars of China(Grant No.21125628)the Major National Scienti fic Instrument Development Project(Grant No.21527812)+3 种基金the National Natural Science Foundation of China(Grant Nos.21406031 and 21476044)the State Key Laboratory of Fine Chemicals(KF1507)the Fundamental Research Funds for the Central Universities(Grant Nos.DUTPJ14RC(3)003)State Key Laboratory of fine chemicals(Panjin)project(Grant No.JH2014009)
文摘Ion conductive membranes(ICMs)are frequently used as separators for energy conversion and storage technologies of fuel cells,flow battery,and hydrogen pump,because of their good ion-selective conduction and low electronic conductivity.Firstly,this feature article reviews the recent studies on the development of new nonfluorinated ICMs with low cost and their macro/micro-structure control.In general,these new nonfluorinated ICMs have lower conductivity than commercial perfluorinated ones,due to their poor ion transport channels.Increasing ion exchange capacity(IEC)would create more continuous hydrophilic channels,thus enhancing the conductivity.However,high IEC also expands the overall hydrophilic domains,weakens the interaction between polymer chains,enhances the mobility of polymer chains,and eventually induces larger swelling.The micro-scale expansion and macro-scale swelling of the ICMs with high IEC could be controlled by limiting the mobility of polymer chains.Based on this strategy,some ef ficient techniques have been developed,including covalent crosslinking,semi-interpenatrating polymer network,and blending.Secondly,this review introduces the optimization of macro/microstructure of both perfluorinated and nonfluorinated ICMs to improve the performance.Macro-scale multilayer composite is an ef ficient way to enhance the mechanical strength and the dimensional stability of the ICMs,and could also decrease the content of per fluorosulfonic acid resin in the membrane,thereby reducing the cost of the perfluorinated ICMs.Long side chain,multiple functionalization,small molecule inducing micro-phase separation,electrospun nano fiber,and organic–inorganic hybrid could construct more ef ficient ion transport channels,improving the ion conductivity of ICMs.
文摘A theoretical basis of optimally designed BRAQWET is pr esented. The optimum parameters of MgZnSSe/ZnSe BRAQWET are obtained by the ca lculation of band-structure according to the depletion approximation.
文摘The solvo―thermal technique is used for the synthesis of [Mn(en)_3]Te_4 (I).The crystal structure has been determined by single crystal X―ray diffraction techniques. Thecrystal belongs to the monoclinic, space group p2_1/c with unit cell:a = 0. 846 1(1), b=1.5653(2),c=1.426 9(2) nm, α = 90°, β=91. 37(1) (3)°, γ=90°, V=1. 889 3(4) nm^3, and Z=4. The resultsshow that the structure contains a linear chain Zintl anion, [Te_4 ]^(2-) and a complex cation,[Mn(en)_3l^(2+). Optical studies have been performed on the powder sample of I, suggesting that thecompound is a semiconductor with a band gap of 0. 73 eV. The semiconductor properties for MnQ_2(Q=S, Se, Te) and [Mn(en)_3]Te_4 have been discussed by molecular orbital theory.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 81173625, 81373458) Thanks for the kind help of Dr. Wang (Pulmonary Division, Boston Children's Hospital, MA, USA), who was extremely helpful in the revision of the language.
文摘Background The mitochondrial Na^+/Ca^2+ exchanger, NCLX, plays an important role in the balance between Ca2. influx and efflux across the mitochondrial inner membrane in endothelial ceils. Mitochondrial metabolism is likely to be affected by the activity of NCLX because Ca^2+ activates several enzymes of the Krebs cycle. It is currently believed that mitochondria are not only centers of energy produc- tion but are also important sites of reactive oxygen species (ROS) generation and nucleotide-binding oligomerization domain receptor 3 (NLRP3) inflammasome activation. Methods & Results This study focused on NCLX function, in rat aortic endothelial cells (RAECs), induced by glucose. First, we detected an increase in NCLX expression in the endothelia of rats with diabetes mellitus, which was induced by an injection of streptozotocin. Next, colocalization of NCLX expression and mitochondria was detected using confocal analysis. Suppression of NCLX expression, using an siRNA construct (siNCLX), enhanced mitochondrial Ca^2+ influx and blocked efflux induced by glucose. Unexpectedly, silencing of NCLX expression induced increased ROS generation and NLRP3 inflammasome activation. Conclusions These findings suggest that NCLX affects glucose-dependent mitochondrial Ca^2+ signaling, thereby regulating ROS generation and NLRP3 in- flammasome activation in high glucose conditions. In the early stages of high glucose stimulation, NCLX expression increases to compensate in order to self-protect mitochondrial maintenance, stability, and function in endothelial cells.
基金Supported by the National Science Foundation(PREM center for interfaces,DMR-1205670)the Robert A.Welch Foundation(Al-0045)
文摘Aluminum doped hydroxyapatite (HA:AI3 +) nanopowders were successfully prepared via a simple and efficient one-pot mechanochemical route. The effects of dopant loading on phase compositions and structural features were assessed by Rietveld analysis. The XRD-Rietveld refinement revealed the stabilization of HA in hexagonal structure for all the samples. The sharpness and intensity of the apatite-derived XRD peaks decreased as the dopant content increased to 10% due to the increase in lattice imperfections and mechanically induced amorphization. The incorpo- ration of A13 + into the HA lattice decreased the unit cell parameters. From the FfiR measurements, the representing bands of apatite were identified in all cases. The mechanosynthesized nanopowders consisted of nanospheroids with an average size of 44 - 20 nm and therefore are promising for bone tissue regeneration.
文摘Ni-Ce0.8Sm.2O.9 (Ni-SDC) cermet was selected as anode material for reduced temperature (800℃) solid oxide fuel cells in this study. The influence of NiO powder fabrication methods for Ni-SDC cermets on the electrode performance was investigated so that the result obtained can be applied to make high-quality anode. Three kinds of NiO powder were synthesized with a fourth kind being available in the market. Four types of anode precursors were fabricated with these NiO powders and Ce0.8Sm.2O.9 (SDC), and then were reduced to anode wafers for sequencing measurement. The electrical conductivity of the anodes was measured and the effect ofmicrostructure was investigated. It was found that the anode electrical conductivity depends strongly on the NiO powder morphologies, microstructure of the cermet anode and particle sizes, which are decided by NiO powder preparation technique. The highest electrical conductivity is obtained for anode cermets with NiO powder synthesized by NiCO3-2Ni(OH)2-4H2O or Ni(NO3)2-6H2O decomposition technique.
基金Supported by the National Defense Preresearch Fund Program(No.99J8.1.1.DZD132)
文摘Grooved gate structure Metal-Oxide-Semiconductor (MOS) device is consideredas the most promising candidate used in deep and super-deep sub-micron region, for it cansuppress hot carrier effect and short channel effect deeply. Based on the hydrodynamic energytransport model, using two-dimensional device simulator Medici, the relation between structureparameters and hot carrier effect immunity for deep-sub-micron N-channel MOSFET's is studiedand compared with that of counterpart conventional planar device in this paper. The examinedstructure parameters include negative junction depth, concave corner and effective channel length.Simulation results show that grooved gate device can suppress hot carrier effect deeply even indeep sub-micron region. The studies also indicate that hot carrier effect is strongly influencedby the concave corner and channel length for grooved gate device. With the increase of concavecorner, the hot carrier effect in grooved gate MOSFET decreases sharply, and with the reducingof effective channel length, the hot carrier effect becomes large.
文摘As global issues become more prominent and complex, various actors in the international community are strengthening global governance through systems of international cooperation. Different international actors have different identities, responsibilities and roles in international institutions due to their comprehensive strengths. They are roughly divided into three types: followers, supporters and leaders. Since the founding of the People's Republic of China in 1949, its process of participation in international institutions and global governance has been obviously staged.In recent years, China has actively participated in various major international activities and carried out a series of diplomatic activities at home, which further demonstrates its involvement from a single participant to both a leader and a participant. In the existing traditional, modified and innovative international institutions, China is essentially playing a dual role, namely the roles of participant and supporter, the supporter and reformer, and the supporter and leader.
文摘MBE growth of ZnS_xSe_1-x thin films on ITO coated glass substrate s were carried o ut using ZnS and Se sources with the substrate temperature ranging from 270℃ to 330℃. The XRD θ/2θ spectra resulted from these films indicated that the as-gro wn polycrystalline ZnS_xSe_1-x thin films had a preferred orientat ion along the (1 11) planes. The evaluated crystal sizes as deduced from the FWHM of the XRD laye r peaks showed strong growth temperature dependence, with the optimized temperat ure being about 290℃. Both AFM and TEM measurements of these thin films also in dicated a similar growth temperature dependence. High quality ZnS_xSe_1- x thin fil m grown at the optimized temperature had the smoothest surface with lowest RMS v alue of 1.2 nm and TEM cross-sectional micrograph showing a well defined column ar structure.
文摘Solid sorbents adsorption is considered as one of the potential options for CO2 capture process. CO2 adsorption on MCM-68 (Si/AI ratio 22) sorbent material was investigated. MCM-68 was synthesized using N,N,N',N'-tetraethylbicyclo [2.2.2] oct-7-ene-2,3:5,6-dipyrrolidinium diiodide (TEBOP^2+(I^+)2) as a structure-directing agent (SDA). CO2 adsorption capacity on MCM-68 sorbent was measured at a broad temperature window i.e. 60 ℃, 300 ℃ and at 400 ℃. The presence of ordered mesoporous structure, high surface area (456 me/g) and high thermal stability (TGA analysis up to 900℃) in MCM-68 are thought to be to be advantageous for the CO2 adsorption in broad temperature window.
基金supported by the Project of Strategic Importance provided by The Hong Kong Polytechnic University(1-ZE29)the Natural Science Foundation of Hubei Province(2014CFB275)+2 种基金the Special(2016T90724,2014T70735)and General(2015M572187,2013M531737)Postdoctoral Science Foundation of Chinathe National High Technology Research and Development Program(2015AA050601)the National Natural Science Foundation of China(61376013,91433203,11674252)
文摘Organic polymer solar cells (OSCs) and organic-inorganic hybrid perovskite solar cells (PSCs) have achieved notable progress over the past several years. A central topic in these fields is exploring electronically efficient, stable and effective hole-transporting layer (HTL) materials. The goal is to enhance hole-collection ability, reduce charge recombination, increase built-in voltage, and hence improve the performance as well as the device stability. Transition metal oxides (TMOs) semiconductors such as NiOx, CuOx, CrOx, MoOx, WO3, and V2O5, have been widely used as HTLs in OSCs. These TMOs are naturally adopted into PSC as HTLs and shows their importance. There are similarities, and also differences in applying TMOs in these two types of main solution processed solar cells. This concise review is on the recent developments of transition metal oxide HTL in OSCs and PSCs. The paper starts from the discussion of the cation valence and electronic structure of the transition metal oxide materials, followed by analyzing the structure-property relationships of these HTLs, which we attempt to give a systematic introduction about the influences of their cation valence, electronic structure, work ftmction and film property on device performance.