Understanding the charge/discharge mechanism of batteries plays an important role in the development of high-performance systems,but extremely complicated reactions are involved.Because these complex phenomena are als...Understanding the charge/discharge mechanism of batteries plays an important role in the development of high-performance systems,but extremely complicated reactions are involved.Because these complex phenomena are also bottlenecks for the establishment of all-sol id-state batteries(ASSB),we conducted multi-scale analysis using combined multi-measurement techniques,to directly observe charge/discharge reactions at hierarchical scales for the oxide-type ASSB using Na as the carrier cation.In particular,all of measurement techniques are applied to cross-section ASSB in the same cell,to complementarily evaluate the elemental distributions and structural changes.From Operando scanning electron microscopy-energy-dispersive X-ray spectroscopy,the Na concentration in the electrode layers changes on the micrometer scale under charge/discharge reactions in the first cycle.Furthermore,Operando Raman spectroscopy reveal changes in the bonding states at the atomic scale in the active material,including changes in reversible structural changes.After cycling the ASSB,the elemental distributions are clearly observed along with the particle shapes and can reveal the Na migration mechanism at the nanometer scale,by time-of-flight secondary ion mass spectrometry.Therefore,this study can provide a fundamental and comprehensive understanding of the charge/discharge mechanism by observing reaction processes at multiple scales.展开更多
Series of mixed metal oxides were synthesized by gel-combustion method and their catalytic activities for soot oxidation were investigated. The catalysts were M-Ce-Zr （M = Mn, Cu, Fe, K, Ba, Sr）, and χK-20Mn-Ce-Zr...Series of mixed metal oxides were synthesized by gel-combustion method and their catalytic activities for soot oxidation were investigated. The catalysts were M-Ce-Zr （M = Mn, Cu, Fe, K, Ba, Sr）, and χK-20Mn-Ce-Zr （χ= 0, 5, 10, 20）, they were characterized by XRD, SEM, TPR and BET surface area techniques. The results of soot temperature programmed oxidation （TPO） in an O2 oxidizing atmosphere indicate that K-Ce-Zr has the highest catalytic activity for soot oxidation under loose contact condition, due to enhancement of the soot and catalyst contacts. On the other hand, under a tight contact condition, Mn-Ce-Zr and Cu-Ce-Zr nano-composites have high activities for soot oxidation and lower the soot TPO peak temperatures by about 280 and 270℃, respectively, as compared to non-catalytic soot oxidation. Furthermore, the addition of up to 10 wt.% potassium oxides into Mn-Ce-Zr increases its catalytic activity and further reduces the soot TPO peak temperature by about 40℃ under loose contact condition.展开更多
Quantum manipulation of macroscopic mechanical systems is of great interest in both fundamental physics and ap- plications ranging from high-precision metrology to quantum information processing. For these purposes, a...Quantum manipulation of macroscopic mechanical systems is of great interest in both fundamental physics and ap- plications ranging from high-precision metrology to quantum information processing. For these purposes, a crucial step is to cool the mechanical system to its quantum ground state. In this review, we focus on the cavity optomechanical cooling, which exploits the cavity enhanced interaction between optical field and mechanical motion to reduce the thermal noise. Recent remarkable theoretical and experimental efforts in this field have taken a major step forward in preparing the mo- tional quantum ground state of mesoscopic mechanical systems. This review first describes the quantum theory of cavity optomechanical cooling, including quantum noise approach and covariance approach; then, the up-to-date experimental progresses are introduced. Finally, new cooling approaches are discussed along the directions of cooling in the strong coupling regime and cooling beyond the resolved sideband limit.展开更多
The structural and magnetic properties of the synthesized pure and functionalized CoFe2O4magnetic nanoparticles(NPs) are studied by analyzing the results from the x-ray diffraction(XRD), transmission electron microsco...The structural and magnetic properties of the synthesized pure and functionalized CoFe2O4magnetic nanoparticles(NPs) are studied by analyzing the results from the x-ray diffraction(XRD), transmission electron microscopy(TEM), FT–IR spectroscopy, thermogravimetry(TG), and vibrating sample magnetometer(VSM). To extract the structure and lattice parameters from the XRD analysis results, we first apply the pseudo-Voigt model function to the experimental data obtained from XRD analysis and then the Rietveld algorithm is used in order to optimize the model function to estimate the true intensity values. Our simulated intensities are in good agreement with the experimental peaks, therefore, all structural parameters such as crystallite size and lattice constant are achieved through this simulation. Magnetic analysis reveals that the synthesized functionalized NPs have a saturation magnetization almost equal to that of pure nanoparticles(PNPs). It is also found that the presence of the turmeric causes a small reduction in coercivity of the functionalized NPs in comparison with PNP. Our TGA and FTIR results show that the turmeric is bonded very well to the surface of the NPs. So it can be inferred that a nancomposite(NC) powder of turmeric and nanoparticles is produced. As an application, the anti-arsenic characteristic of turmeric makes the synthesized functionalized NPs or NC powder a good candidate for arsenic removal from polluted industrial waste water.展开更多
Broadband waveguiding through light-emitting strips directly written in a blank lithium fluoride crystal with a femtosecond laser is reported. Light guiding was observed at several optical wavelengths, from blue, 458 ...Broadband waveguiding through light-emitting strips directly written in a blank lithium fluoride crystal with a femtosecond laser is reported. Light guiding was observed at several optical wavelengths, from blue, 458 nm, to near-infrared, at 155nm. Visible photoluminescence spectra of the optically active F2 and F33 color centers produced by the fs laser writing process were measured. The wavelength-dependent refractive index increase was estimated to be in the order of 10-3-10-4 in the visible and near-infrared spectral intervals, which is consistent with the stable formation of point defects in LiF.展开更多
1.Introduction Grain boundaries(GBs)in polycrystalline materials exhibit unique atomic structures due to the lattice disorder,resulting in properties that are distinct from the bulk[1-5].Doping foreign atoms in the GB...1.Introduction Grain boundaries(GBs)in polycrystalline materials exhibit unique atomic structures due to the lattice disorder,resulting in properties that are distinct from the bulk[1-5].Doping foreign atoms in the GBs has become one of the most popular strategies for modifying material properties,such as grain growth behaviors,microstructures,and mechanical properties in polycrystals[6-12].These dopants typically diffuse along the GBs at elevated temper-atures and ultimately segregate to preferred GB atomic sites to modify the structures of the GBs[13-15].Consequently,GB seg-regation of dopants has gained significant interests,and a funda-mental understanding of the origin of GB segregation phenomena is crucial for the rational design of materials with unprecedented properties.展开更多
The magmatic arcs in the north-west region of Pakistan comprises of numerous volcanic and plutonic bodies of different ages and compositions evolved during the subduction of the Neo- Tethys Ocean under the Eurasian su...The magmatic arcs in the north-west region of Pakistan comprises of numerous volcanic and plutonic bodies of different ages and compositions evolved during the subduction of the Neo- Tethys Ocean under the Eurasian supercontinent. This study focusses on the examination of the granitoids of the Kohistan batholith (a part of Kohistan-Ladakh Island Arc;KLIA) and the Khunjerab pluton, concentrating on their petrological traits, mineral chemistry, in-situ zircon U-Pb geochronology, and whole-rock major and trace element geochemistry. According to zircon U-Pb dating, the Kohistan batholith granitoid was emplaced around 91.7 ± 0.3 Ma, while zircons of the Khunjerab pluton yield ages of 106.4 ± 0.4 Ma and 106.4 ± 1.0 Ma. All the samples from both magmatic units have calcic to calc-alkaline (Na_(2)O + K_(2)O: 3.6–10.6 wt.% and SiO_(2): 60–73 wt.%), metaluminous to peraluminous properties (Aluminum Saturation Index (ASI): 0.9–1.2). Notably, Nb, Ta, and Ti show depletion, while large ion lithophile elements like Cs, Rb, and K have been enriched. Additionally, we find that SiO_(2) and P_(2)O_(5) have a negative correlation while Rb and Th have a positive correlation, which confirm an I-type arc magmatism. Together with the published literature, TEM analysis, and thermal modelling, our zircon U-Pb results point to a period of continuous magmatic activity from the Late Jurassic to the Late Cretaceous (between 150 Ma and 91 Ma) in the Kohistan Island arc region while the Khunjerab pluton (part of Karakorum block/Eurasian plate) experienced widespread magmatism around 120 Ma to 106 Ma. With SiO_(2) concentrations ranging from 67.5–73.3 wt.% and 60–71.4 wt.% and relatively low alkali (Na_(2)O + K_(2)O) contents between 3.6–10.6 wt.% and 5.1–7.4 wt.% in the Kohistan batholith and Khunjerab pluton respectively, showing clear signs of acidity. The whole rock as well as the mineral geochemical analysis and the elevated water contents (8–10 wt.% and 3.1–3.5 wt.%) inferred from amphibole and biotite chemistry respectively, indicates that the Kohistan batholith was most likely formed through partial melting of a (hydrous) magma originating from a more or less altered metasomatized mantle wedge. Likewise, the Khunjerab pluton whole rock geochemistry also indicates its origin through partial melting of magma originating from an altered metasomatized mantle wedge. This study also shows that both units are not only different in terms of the nature of magmatism but also in terms of their ages i.e., continental arc magmatism occurred in the Khunjerab (Karakoram) block in the middle Cretaceous (106 Ma) while island arc magmatism occurred on the Kohistan side in the late Cretaceous (91 Ma). Further, this study also investigate why multi-grain U-Pb zircon dating is necessary for studying magmatic rocks by using transmission electron microscopy.展开更多
Ground state cooling of massive mechanical objects remains a difficult task restricted by the unresolved mechanical sidebands. We propose an optomechanically-induced-transparency cooling scheme to achieve ground state...Ground state cooling of massive mechanical objects remains a difficult task restricted by the unresolved mechanical sidebands. We propose an optomechanically-induced-transparency cooling scheme to achieve ground state cooling of mechanical motion without the resolved sideband condition in a pure optomechanical system with two mechanical modes coupled to the same optical cavity mode. We show that ground state cooling is achievable for sideband resolution ωm/k as low as - 0.003. This provides a new route for quantum manipulation of massive macroscopic devices and high-precision measurements.展开更多
Optical solitons—stable waves balancing delicately between nonlinearities and dispersive effects—have advanced the field of ultrafast optics and dynamics,with contributions spanning from supercontinuum generation to...Optical solitons—stable waves balancing delicately between nonlinearities and dispersive effects—have advanced the field of ultrafast optics and dynamics,with contributions spanning from supercontinuum generation to soliton fission,optical event horizons,Hawking radiation and optical rogue waves,among others.Here,we investigate picojoule soliton dynamics in silicon slow-light,photonic-bandgap waveguides under the influence of Drude-modeled,free-carrier-induced nonlinear effects.Using real-time and single-shot amplified dispersive Fourier transform spectroscopy simultaneously with high-fidelity cross-correlation frequency resolved optical gating at femtojoule sensitivity and femtosecond resolution,we examine the soliton stability limits,the soliton dynamics including free-carrier quartic slow-light scaling and acceleration,and the Drude electron–hole plasma-induced perturbations in the Cherenkov radiation and modulation instability.Our real-time single-shot and time-averaged cross-correlation measurements are matched with our detailed theoretical modeling,examining the reduced group velocity free-carrier kinetics on solitons at the picojoule scale.展开更多
A first-principles-based computational tool for simulating phonons of magnetic random solid solutions including thermal magnetic fluctuations is developed.The method takes fluctuations of force constants due to magnet...A first-principles-based computational tool for simulating phonons of magnetic random solid solutions including thermal magnetic fluctuations is developed.The method takes fluctuations of force constants due to magnetic excitations as well as due to chemical disorder into account.The developed approach correctly predicts the experimentally observed unusual phonon hardening of a transverse acoustic mode in Fe–Pd an Fe–Pt Invar alloys with increasing temperature.This peculiar behavior,which cannot be explained within a conventional harmonic picture,turns out to be a consequence of thermal magnetic fluctuations.The proposed methodology can be straightforwardly applied to a wide range of materials to reveal new insights into physical behaviors and to design materials through computation,which were not accessible so far.展开更多
Concentrations of intrinsic and extrinsic point defects in crystalline materials with a bandgap are typically calculated in a constant-μapproach from defect formation energies based on density functional theory.In th...Concentrations of intrinsic and extrinsic point defects in crystalline materials with a bandgap are typically calculated in a constant-μapproach from defect formation energies based on density functional theory.In this work,calculations of thermal and charge equilibria among point defects are extended to a constant-N approach.The two approaches for point-defect equilibria are comparatively demonstrated in the application to Mg_(2)Si doped with Li,Na,and Ag,which is a lightweight and environmentally friendly thermoelectric candidate material.Our results reveal the systematic behavior of defect and carrier concentrations.The dopant atoms form interstitial defects at similar concentrations to substitutional defects at the Mg sites,resulting in significantly reduced free-carrier concentrations compared to the expected values.The developed procedures could be utilized to find an optimal avenue for achieving higher carrier concentrations,e.g.,with regard to annealing temperature and the concentration of dopant atoms,in various semiconductors and insulators.展开更多
Martensitic transformation with good structural compatibility between parent and martensitic phases are required for shape memory alloys(SMAs)in terms of functional stability.In this study,first-principles-based mater...Martensitic transformation with good structural compatibility between parent and martensitic phases are required for shape memory alloys(SMAs)in terms of functional stability.In this study,first-principles-based materials screening is systematically performed to investigate the intermetallic compounds with the martensitic phases by focusing on energetic and dynamical stabilities as well as structural compatibility with the parent phase.The B2,D0_(3),and L2_(1) crystal structures are considered as the parent phases,and the 2H and 6M structures are considered as the martensitic phases.In total,3384 binary and 3243 ternary alloys with stoichiometric composition ratios are investigated.It is found that 187 alloys survive after the screening.Some of the surviving alloys are constituted by the chemical elements already widely used in SMAs,but other various metallic elements are also found in the surviving alloys.The energetic stability of the surviving alloys is further analyzed by comparison with the data in Materials Project Database(MPD)to examine the alloys whose martensitic structures may cause further phase separation or transition to the other structures.展开更多
In recent years,there has been increased interest in the use of nanostructures in various industries,such as the food,textile,pharmaceutical,electronics,and chemical industries.Most of these applications require a pro...In recent years,there has been increased interest in the use of nanostructures in various industries,such as the food,textile,pharmaceutical,electronics,and chemical industries.Most of these applications require a proper preparation of specific nanomaterials.In this study,we characterized silver nanoparticles(AgNPs)stabilized with polyvinylpyrrolidone and prepared in aqueous suspensions using dynamic light scattering,atomic force microscopy,and transmission electron microscopy.We aimed to compare the influence of different AgNP preparation procedures,specifically autoclaving,sonication,and a combination of both,on the agglomeration of these nanoparticles.Additionally,the toxicity of the NPs after the selected sterilization methods toward the EA.hy926 endothelial cell line was determined using trypan blue labeling,2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide(XTT)tetrazolium salt reduction tests,and the 3-[4,5-dimethylthiazol-2yl]-2,5-diphenyltetrazolium bromide(MTT)tetrazolium bromide test.Based on the obtained results,we concluded that cells exposed to AgNPs after sonication had similar viability values above 80%across all cellular viability tests.Conversely,the cellular viability values of the EA.hy926 cell line exposed to the autoclaved AgNP solutions differed.From the XTT tests,we observed a falsely determined cellular viability value above 100%with a simultaneous increase in the XTT-measured absorbance for the cellular medium after autoclaving.However,the other viability tests showed a cellular viability value below 25%.The results prove the importance of selecting an appropriate method for measuring cell viability,especially for cells exposed to previously sterilized nanomaterials.展开更多
We investigate the ultrafast nonlinear phenomena of picosecond chirped non-ideal hyperbolic secant pulse evolution in silicon photonic nanowire waveguides with sum frequency generation cross-correlation frequencyresol...We investigate the ultrafast nonlinear phenomena of picosecond chirped non-ideal hyperbolic secant pulse evolution in silicon photonic nanowire waveguides with sum frequency generation cross-correlation frequencyresolved optical gating and nonlinear Schrodinger equation modeling. Pulse broadening and spectral blue shifts are observed experimentally, and they show remarkable agreements with numerical predictions. Nonlinear losses dominate the pulse broadening and limit the spectral bandwidth broadening induced by self-phase modu- lation. The initial chirp results in noticeable bandwidth compression and aggravation of blue shifts in the pres- ence of nonlinear losses, whereas it plays a negligible role in the output pulse temporal intensity distribution.展开更多
基金This article is based on results obtained from a project,Grant JPNP14004,commissioned by the New Energy and Industrial Technology Development Organization(NEDO)。
文摘Understanding the charge/discharge mechanism of batteries plays an important role in the development of high-performance systems,but extremely complicated reactions are involved.Because these complex phenomena are also bottlenecks for the establishment of all-sol id-state batteries(ASSB),we conducted multi-scale analysis using combined multi-measurement techniques,to directly observe charge/discharge reactions at hierarchical scales for the oxide-type ASSB using Na as the carrier cation.In particular,all of measurement techniques are applied to cross-section ASSB in the same cell,to complementarily evaluate the elemental distributions and structural changes.From Operando scanning electron microscopy-energy-dispersive X-ray spectroscopy,the Na concentration in the electrode layers changes on the micrometer scale under charge/discharge reactions in the first cycle.Furthermore,Operando Raman spectroscopy reveal changes in the bonding states at the atomic scale in the active material,including changes in reversible structural changes.After cycling the ASSB,the elemental distributions are clearly observed along with the particle shapes and can reveal the Na migration mechanism at the nanometer scale,by time-of-flight secondary ion mass spectrometry.Therefore,this study can provide a fundamental and comprehensive understanding of the charge/discharge mechanism by observing reaction processes at multiple scales.
文摘Series of mixed metal oxides were synthesized by gel-combustion method and their catalytic activities for soot oxidation were investigated. The catalysts were M-Ce-Zr （M = Mn, Cu, Fe, K, Ba, Sr）, and χK-20Mn-Ce-Zr （χ= 0, 5, 10, 20）, they were characterized by XRD, SEM, TPR and BET surface area techniques. The results of soot temperature programmed oxidation （TPO） in an O2 oxidizing atmosphere indicate that K-Ce-Zr has the highest catalytic activity for soot oxidation under loose contact condition, due to enhancement of the soot and catalyst contacts. On the other hand, under a tight contact condition, Mn-Ce-Zr and Cu-Ce-Zr nano-composites have high activities for soot oxidation and lower the soot TPO peak temperatures by about 280 and 270℃, respectively, as compared to non-catalytic soot oxidation. Furthermore, the addition of up to 10 wt.% potassium oxides into Mn-Ce-Zr increases its catalytic activity and further reduces the soot TPO peak temperature by about 40℃ under loose contact condition.
基金Project supported by the National Basic Research Program of China(Grant No.2013CB328704)the National Natural Science Foundation of China(Grant Nos.11004003,11222440,and 11121091)+1 种基金the Research Fund for the Doctoral Program of Higher Education of China(Grant No.20120001110068)the Scholarship Award for Excellent Doctoral Student granted by Ministry of Education,China
文摘Quantum manipulation of macroscopic mechanical systems is of great interest in both fundamental physics and ap- plications ranging from high-precision metrology to quantum information processing. For these purposes, a crucial step is to cool the mechanical system to its quantum ground state. In this review, we focus on the cavity optomechanical cooling, which exploits the cavity enhanced interaction between optical field and mechanical motion to reduce the thermal noise. Recent remarkable theoretical and experimental efforts in this field have taken a major step forward in preparing the mo- tional quantum ground state of mesoscopic mechanical systems. This review first describes the quantum theory of cavity optomechanical cooling, including quantum noise approach and covariance approach; then, the up-to-date experimental progresses are introduced. Finally, new cooling approaches are discussed along the directions of cooling in the strong coupling regime and cooling beyond the resolved sideband limit.
基金supported by the University of Guilanthe Iran Nanotechnology Initiative Council
文摘The structural and magnetic properties of the synthesized pure and functionalized CoFe2O4magnetic nanoparticles(NPs) are studied by analyzing the results from the x-ray diffraction(XRD), transmission electron microscopy(TEM), FT–IR spectroscopy, thermogravimetry(TG), and vibrating sample magnetometer(VSM). To extract the structure and lattice parameters from the XRD analysis results, we first apply the pseudo-Voigt model function to the experimental data obtained from XRD analysis and then the Rietveld algorithm is used in order to optimize the model function to estimate the true intensity values. Our simulated intensities are in good agreement with the experimental peaks, therefore, all structural parameters such as crystallite size and lattice constant are achieved through this simulation. Magnetic analysis reveals that the synthesized functionalized NPs have a saturation magnetization almost equal to that of pure nanoparticles(PNPs). It is also found that the presence of the turmeric causes a small reduction in coercivity of the functionalized NPs in comparison with PNP. Our TGA and FTIR results show that the turmeric is bonded very well to the surface of the NPs. So it can be inferred that a nancomposite(NC) powder of turmeric and nanoparticles is produced. As an application, the anti-arsenic characteristic of turmeric makes the synthesized functionalized NPs or NC powder a good candidate for arsenic removal from polluted industrial waste water.
文摘Broadband waveguiding through light-emitting strips directly written in a blank lithium fluoride crystal with a femtosecond laser is reported. Light guiding was observed at several optical wavelengths, from blue, 458 nm, to near-infrared, at 155nm. Visible photoluminescence spectra of the optically active F2 and F33 color centers produced by the fs laser writing process were measured. The wavelength-dependent refractive index increase was estimated to be in the order of 10-3-10-4 in the visible and near-infrared spectral intervals, which is consistent with the stable formation of point defects in LiF.
基金supported by the Grant-in-Aid for Scientific Research(S)(No.JP22H04960)Grant-in-Aid for Scientific Research on Innovative Areas(No.JP19H05788)+1 种基金Grants-in-Aid for Early-Career Scientists(No.JP22K14463)from the Japan Society for the Promotion of Science(JSPS)supported by the Advanced Research Infrastructure for Materials and Nanotechnology Japan(No.JPMXP1223UT0054)by the Ministry of Education,Culture,Sports,Science and Technology(MEXT).
文摘1.Introduction Grain boundaries(GBs)in polycrystalline materials exhibit unique atomic structures due to the lattice disorder,resulting in properties that are distinct from the bulk[1-5].Doping foreign atoms in the GBs has become one of the most popular strategies for modifying material properties,such as grain growth behaviors,microstructures,and mechanical properties in polycrystals[6-12].These dopants typically diffuse along the GBs at elevated temper-atures and ultimately segregate to preferred GB atomic sites to modify the structures of the GBs[13-15].Consequently,GB seg-regation of dopants has gained significant interests,and a funda-mental understanding of the origin of GB segregation phenomena is crucial for the rational design of materials with unprecedented properties.
基金funded by the Higher Education Commission of Pakistan under the Faculty Development Program for the Khushal Khan Khattak University,Karak,Pakistan with grant No.386-388/PC/PAB/KKKUK/21Partial funds are provided by the University of Vienna,Austria.
文摘The magmatic arcs in the north-west region of Pakistan comprises of numerous volcanic and plutonic bodies of different ages and compositions evolved during the subduction of the Neo- Tethys Ocean under the Eurasian supercontinent. This study focusses on the examination of the granitoids of the Kohistan batholith (a part of Kohistan-Ladakh Island Arc;KLIA) and the Khunjerab pluton, concentrating on their petrological traits, mineral chemistry, in-situ zircon U-Pb geochronology, and whole-rock major and trace element geochemistry. According to zircon U-Pb dating, the Kohistan batholith granitoid was emplaced around 91.7 ± 0.3 Ma, while zircons of the Khunjerab pluton yield ages of 106.4 ± 0.4 Ma and 106.4 ± 1.0 Ma. All the samples from both magmatic units have calcic to calc-alkaline (Na_(2)O + K_(2)O: 3.6–10.6 wt.% and SiO_(2): 60–73 wt.%), metaluminous to peraluminous properties (Aluminum Saturation Index (ASI): 0.9–1.2). Notably, Nb, Ta, and Ti show depletion, while large ion lithophile elements like Cs, Rb, and K have been enriched. Additionally, we find that SiO_(2) and P_(2)O_(5) have a negative correlation while Rb and Th have a positive correlation, which confirm an I-type arc magmatism. Together with the published literature, TEM analysis, and thermal modelling, our zircon U-Pb results point to a period of continuous magmatic activity from the Late Jurassic to the Late Cretaceous (between 150 Ma and 91 Ma) in the Kohistan Island arc region while the Khunjerab pluton (part of Karakorum block/Eurasian plate) experienced widespread magmatism around 120 Ma to 106 Ma. With SiO_(2) concentrations ranging from 67.5–73.3 wt.% and 60–71.4 wt.% and relatively low alkali (Na_(2)O + K_(2)O) contents between 3.6–10.6 wt.% and 5.1–7.4 wt.% in the Kohistan batholith and Khunjerab pluton respectively, showing clear signs of acidity. The whole rock as well as the mineral geochemical analysis and the elevated water contents (8–10 wt.% and 3.1–3.5 wt.%) inferred from amphibole and biotite chemistry respectively, indicates that the Kohistan batholith was most likely formed through partial melting of a (hydrous) magma originating from a more or less altered metasomatized mantle wedge. Likewise, the Khunjerab pluton whole rock geochemistry also indicates its origin through partial melting of magma originating from an altered metasomatized mantle wedge. This study also shows that both units are not only different in terms of the nature of magmatism but also in terms of their ages i.e., continental arc magmatism occurred in the Khunjerab (Karakoram) block in the middle Cretaceous (106 Ma) while island arc magmatism occurred on the Kohistan side in the late Cretaceous (91 Ma). Further, this study also investigate why multi-grain U-Pb zircon dating is necessary for studying magmatic rocks by using transmission electron microscopy.
基金supported by the National Basic Research Program of China(Grant Nos.2013CB328704 and 2013CB921904)the National Natural Science Foundation of China(Grant Nos.11474011,11222440 and 61435001)+1 种基金the Research Fund for the Doctoral Program of Higher Education of China(Grant No.20120001110068)the Optical Radiation Cooling and Heating in Integrated Devices Program of Defense Advanced Research Projects Agency(Grant No.C11L10831)
文摘Ground state cooling of massive mechanical objects remains a difficult task restricted by the unresolved mechanical sidebands. We propose an optomechanically-induced-transparency cooling scheme to achieve ground state cooling of mechanical motion without the resolved sideband condition in a pure optomechanical system with two mechanical modes coupled to the same optical cavity mode. We show that ground state cooling is achievable for sideband resolution ωm/k as low as - 0.003. This provides a new route for quantum manipulation of massive macroscopic devices and high-precision measurements.
基金support is from the Office of Naval Research with grant N00014-14-1-0041UESTC Young Faculty Award ZYGX2015KYQD051+2 种基金the 111 project(B14039)funding from NSFC Grant 61070040funding from AFOSR Young Investigator Award with grant FA9550-15-1-0081.
文摘Optical solitons—stable waves balancing delicately between nonlinearities and dispersive effects—have advanced the field of ultrafast optics and dynamics,with contributions spanning from supercontinuum generation to soliton fission,optical event horizons,Hawking radiation and optical rogue waves,among others.Here,we investigate picojoule soliton dynamics in silicon slow-light,photonic-bandgap waveguides under the influence of Drude-modeled,free-carrier-induced nonlinear effects.Using real-time and single-shot amplified dispersive Fourier transform spectroscopy simultaneously with high-fidelity cross-correlation frequency resolved optical gating at femtojoule sensitivity and femtosecond resolution,we examine the soliton stability limits,the soliton dynamics including free-carrier quartic slow-light scaling and acceleration,and the Drude electron–hole plasma-induced perturbations in the Cherenkov radiation and modulation instability.Our real-time single-shot and time-averaged cross-correlation measurements are matched with our detailed theoretical modeling,examining the reduced group velocity free-carrier kinetics on solitons at the picojoule scale.
基金Funding by the Ministry of Education,Culture,Sports,Science,and Technology(MEXT)Japan,through Elements Strategy Initiative for Structural Materials(ESISM)of Kyoto University+4 种基金by the Japan Society for the Promotion of Science(JSPS)KAKENHI Grant-in-Aid for Young Scientist(B)(Grant No.16K18228)by the European Research Council under the EU’s 7th Framework Programme(FP7/2007-2013)/ERC Grant agreement 290998the Grant-in-Aid for Scientific Research on Innovative Areas Nano Informatics(Grant No.25106005)from the Japan Society for the Promotion of Science(JSPS)by the Deutsche Forschungsgemeinschaft(DFG)for the scholarship KO 5080/1-1by the DFG for their funding within the priority programme SPP 1599.
文摘A first-principles-based computational tool for simulating phonons of magnetic random solid solutions including thermal magnetic fluctuations is developed.The method takes fluctuations of force constants due to magnetic excitations as well as due to chemical disorder into account.The developed approach correctly predicts the experimentally observed unusual phonon hardening of a transverse acoustic mode in Fe–Pd an Fe–Pt Invar alloys with increasing temperature.This peculiar behavior,which cannot be explained within a conventional harmonic picture,turns out to be a consequence of thermal magnetic fluctuations.The proposed methodology can be straightforwardly applied to a wide range of materials to reveal new insights into physical behaviors and to design materials through computation,which were not accessible so far.
基金T.O.acknowledges partial support by a Grant-in-Aid for Scientific Research(C)(Grant Number 21K04648)Grant-in-Aid for Scientific Research on Innovative Areas(Grant Number 19H05792)from the Japan Society for the Promotion of Science(JSPS).
文摘Concentrations of intrinsic and extrinsic point defects in crystalline materials with a bandgap are typically calculated in a constant-μapproach from defect formation energies based on density functional theory.In this work,calculations of thermal and charge equilibria among point defects are extended to a constant-N approach.The two approaches for point-defect equilibria are comparatively demonstrated in the application to Mg_(2)Si doped with Li,Na,and Ag,which is a lightweight and environmentally friendly thermoelectric candidate material.Our results reveal the systematic behavior of defect and carrier concentrations.The dopant atoms form interstitial defects at similar concentrations to substitutional defects at the Mg sites,resulting in significantly reduced free-carrier concentrations compared to the expected values.The developed procedures could be utilized to find an optimal avenue for achieving higher carrier concentrations,e.g.,with regard to annealing temperature and the concentration of dopant atoms,in various semiconductors and insulators.
基金supported by Grant-in-Aid for Scientific Research(A)and Grant-in-Aid for Scientific Research on Innovative Areas“Nano Informatics”(Grant No.25106005)from the Japan Society for the Promotion of Science(JSPS)Support program for starting up innovation hub on Materials research by Information Integration”Initiative from Japan Science and Technology Agency+2 种基金Grant-in-Aid for International Research Fellow of JSPS(Grant No.2604376)and JSPS fellowshipsGrant-in-Aid for Young Scientist(B)of JSPS(Grant No.16K18228)Funding by the Ministry of Education,Culture,Sports,Science and Technology(MEXT),Japan,through Elements Strategy Initiative for Structural Materials(ESISM)of Kyoto University,is also gratefully acknowledged.
文摘Martensitic transformation with good structural compatibility between parent and martensitic phases are required for shape memory alloys(SMAs)in terms of functional stability.In this study,first-principles-based materials screening is systematically performed to investigate the intermetallic compounds with the martensitic phases by focusing on energetic and dynamical stabilities as well as structural compatibility with the parent phase.The B2,D0_(3),and L2_(1) crystal structures are considered as the parent phases,and the 2H and 6M structures are considered as the martensitic phases.In total,3384 binary and 3243 ternary alloys with stoichiometric composition ratios are investigated.It is found that 187 alloys survive after the screening.Some of the surviving alloys are constituted by the chemical elements already widely used in SMAs,but other various metallic elements are also found in the surviving alloys.The energetic stability of the surviving alloys is further analyzed by comparison with the data in Materials Project Database(MPD)to examine the alloys whose martensitic structures may cause further phase separation or transition to the other structures.
基金financed by The National Science Centre,project title:“The influence of selected nanoparticles on the elastic properties of endothelial cells evaluated using atomic force microscopy”,agreement No.2017/26/D/ST4/00918.
文摘In recent years,there has been increased interest in the use of nanostructures in various industries,such as the food,textile,pharmaceutical,electronics,and chemical industries.Most of these applications require a proper preparation of specific nanomaterials.In this study,we characterized silver nanoparticles(AgNPs)stabilized with polyvinylpyrrolidone and prepared in aqueous suspensions using dynamic light scattering,atomic force microscopy,and transmission electron microscopy.We aimed to compare the influence of different AgNP preparation procedures,specifically autoclaving,sonication,and a combination of both,on the agglomeration of these nanoparticles.Additionally,the toxicity of the NPs after the selected sterilization methods toward the EA.hy926 endothelial cell line was determined using trypan blue labeling,2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide(XTT)tetrazolium salt reduction tests,and the 3-[4,5-dimethylthiazol-2yl]-2,5-diphenyltetrazolium bromide(MTT)tetrazolium bromide test.Based on the obtained results,we concluded that cells exposed to AgNPs after sonication had similar viability values above 80%across all cellular viability tests.Conversely,the cellular viability values of the EA.hy926 cell line exposed to the autoclaved AgNP solutions differed.From the XTT tests,we observed a falsely determined cellular viability value above 100%with a simultaneous increase in the XTT-measured absorbance for the cellular medium after autoclaving.However,the other viability tests showed a cellular viability value below 25%.The results prove the importance of selecting an appropriate method for measuring cell viability,especially for cells exposed to previously sterilized nanomaterials.
基金This research was supported by the National Natural Science Foundation of China （NSFC） under Grant No. 61070040, 61108089, 61205087 and 61107005. We thank James F. McMillan and Jangjun Zheng for their help when performing some of the measurements in Optical Nanostructures Laboratory in Columbia University.
文摘We investigate the ultrafast nonlinear phenomena of picosecond chirped non-ideal hyperbolic secant pulse evolution in silicon photonic nanowire waveguides with sum frequency generation cross-correlation frequencyresolved optical gating and nonlinear Schrodinger equation modeling. Pulse broadening and spectral blue shifts are observed experimentally, and they show remarkable agreements with numerical predictions. Nonlinear losses dominate the pulse broadening and limit the spectral bandwidth broadening induced by self-phase modu- lation. The initial chirp results in noticeable bandwidth compression and aggravation of blue shifts in the pres- ence of nonlinear losses, whereas it plays a negligible role in the output pulse temporal intensity distribution.
