The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform
Noritaka Mizuno - One of the best experts on this subject based on the ideXlab platform.
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reduction induced highly selective uptake of cesium ions by an Ionic Crystal based on silicododecamolybdate
Angewandte Chemie, 2016Co-Authors: Saori Seino, Ryosuke Kawahara, Noritaka Mizuno, Sayaka Uchida, Yoshiyuki OgasawaraAbstract:Cation adsorption and exchange has been an important topic in both basic and applied chemistry relevant to materials synthesis and chemical conversion, as well as purification and separation. Selective Cs+ uptake from aqueous solutions is especially important because Cs+ is expensive and is contained in radioactive wastes. However, the reported adsorbents incorporate Rb+ as well as Cs+, and an adsorbent with high selectivity toward Cs+ has not yet been reported. Highly selective uptake of Cs+ by an Ionic Crystal (etpyH)2[Cr3O(OOCH)6(etpy)3]2[α-SiMo12O40]⋅3 H2O (etpy =4-ethylpyridine) is described. The compound incorporated up to 3.8 mol(Cs+) mol(s)−1 (where s=solid) by cation-exchange with etpyH+ and reduction of silicododecamolybdate with ascorbic acid. The amount of Cs+ uptake was comparable to that of Prussian blue, which is widely recognized as a good Cs+ adsorbent. Moreover, other alkali-metal and alkaline-earth-metal cations were almost completely excluded (<0.2 mol mol(s)−1).
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a functional mesoporous Ionic Crystal based on polyoxometalate
Dalton Transactions, 2016Co-Authors: Ryosuke Kawahara, Kazuma Niinomi, Junko N Kondo, Mitsuhiro Hibino, Noritaka Mizuno, Sayaka UchidaAbstract:A mesoporous Ionic Crystal is synthesized with a polyoxometalate and a macrocation with polar cyano groups. The compound possesses one-dimensional mesopores with an opening of 3.0 × 2.0 nm. The compound shows high proton conductivity and catalytic activity, which are due to the water molecules in the mesopores.
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Highly Selective Sorption of Small Unsaturated Hydrocarbons by Nonporous Flexible Framework with Silver Ion
Journal of the American Chemical Society, 2008Co-Authors: Sayaka Uchida, Ryosuke Kawamoto, Hanae Tagami, Yoshinao Nakagawa, Noritaka MizunoAbstract:Ag2[Cr3O(OOCC2H5)6(H2O)3]2[α-SiW12O40] [1] is a nonporous flexible Ionic Crystal composed of 2D-layers of polyoxometalates ([α-SiW12O40]4−) and macrocations ([Cr3O(OOCC2H5)6(H2O)3]+) stacking along the b-axis. The silver ions are located in the vicinity of the oxygen atoms of the polyoxometalates. The sorption amounts of small unsaturated hydrocarbons such as ethylene, propylene, n-butene, acetylene, and methyl acetylene into 1 are comparable to or larger than 1.0 mol mol−1 and large hystereses are observed, while those of paraffins and larger unsaturated hydrocarbons are smaller than the adsorption on the external surface (
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channel selective independent sorption and collection of hydrophilic and hydrophobic molecules by cs2 cr3o oocc2h5 6 h2o 3 2 α siw12o40 Ionic Crystal
Journal of the American Chemical Society, 2006Co-Authors: Chunjie Jiang, Sayaka Uchida, Aldes Lesbani, Ryosuke Kawamoto, Noritaka MizunoAbstract:An Ionic Crystal of Cs2[Cr3O(OOCC2H5)6(H2O)3]2[α-SiW12O40]·4H2O 1a with hydrophilic and hydrophobic channels has been designed and successfully synthesized. The guest-free phase 1b sorbs dichloromethane and water in the hydrophobic and hydrophilic channels, respectively. The rate and equilibrium amount of the dichloromethane sorption into the hydrophobic channel and those of water into the hydrophilic channel were independent of each other. The sorption properties can be applied to the channel-selective sorption and collection of hydrophobic (dichloromethane) and hydrophilic (water) molecules from the mixture.
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amphiphilic guest sorption of k2 cr3o oocc2h5 6 h2o 3 2 α siw12o40 Ionic Crystal
Journal of the American Chemical Society, 2005Co-Authors: Ryosuke Kawamoto, Sayaka Uchida, Noritaka MizunoAbstract:An Ionic Crystal K2[Cr3O(OOCC2H5)6(H2O)3]2[α-SiW12O40]·3H2O (1a) is synthesized by the complexation of a Keggin-type polyoxometalate of [α-SiW12O40]4- with K+ and a macrocation of [Cr3O(OOCC2H5)6(H2O)3]+. Compound 1a possesses both hydrophilic and hydrophobic channels in the Crystal lattice. The 3 mol mol-1 of the water of Crystallization in 1a resides in the hydrophilic channel. The water of Crystallization is removed by the evacuation at 303 K to form the guest-free phase 1b with small changes in the lattice lengths (±0.2 A). The water sorption profile is reproduced by the single rate constant. Therefore, the water sorbed probably resides in the hydrophilic channel. Compound 1b sorbs various kinds of polar organic molecules, and the amounts of ≤C3 alcohols are comparable to or larger than that of water, while chlorocarbons with no hydrogen-bonding ability and nonpolar molecules are excluded. Thus, 1b showed the amphiphilic sorption property. The states of the polar organic molecules sorbed in 1b have be...
Sayaka Uchida - One of the best experts on this subject based on the ideXlab platform.
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reduction induced highly selective uptake of cesium ions by an Ionic Crystal based on silicododecamolybdate
Angewandte Chemie, 2016Co-Authors: Saori Seino, Ryosuke Kawahara, Noritaka Mizuno, Sayaka Uchida, Yoshiyuki OgasawaraAbstract:Cation adsorption and exchange has been an important topic in both basic and applied chemistry relevant to materials synthesis and chemical conversion, as well as purification and separation. Selective Cs+ uptake from aqueous solutions is especially important because Cs+ is expensive and is contained in radioactive wastes. However, the reported adsorbents incorporate Rb+ as well as Cs+, and an adsorbent with high selectivity toward Cs+ has not yet been reported. Highly selective uptake of Cs+ by an Ionic Crystal (etpyH)2[Cr3O(OOCH)6(etpy)3]2[α-SiMo12O40]⋅3 H2O (etpy =4-ethylpyridine) is described. The compound incorporated up to 3.8 mol(Cs+) mol(s)−1 (where s=solid) by cation-exchange with etpyH+ and reduction of silicododecamolybdate with ascorbic acid. The amount of Cs+ uptake was comparable to that of Prussian blue, which is widely recognized as a good Cs+ adsorbent. Moreover, other alkali-metal and alkaline-earth-metal cations were almost completely excluded (<0.2 mol mol(s)−1).
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a functional mesoporous Ionic Crystal based on polyoxometalate
Dalton Transactions, 2016Co-Authors: Ryosuke Kawahara, Kazuma Niinomi, Junko N Kondo, Mitsuhiro Hibino, Noritaka Mizuno, Sayaka UchidaAbstract:A mesoporous Ionic Crystal is synthesized with a polyoxometalate and a macrocation with polar cyano groups. The compound possesses one-dimensional mesopores with an opening of 3.0 × 2.0 nm. The compound shows high proton conductivity and catalytic activity, which are due to the water molecules in the mesopores.
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Highly Selective Sorption of Small Unsaturated Hydrocarbons by Nonporous Flexible Framework with Silver Ion
Journal of the American Chemical Society, 2008Co-Authors: Sayaka Uchida, Ryosuke Kawamoto, Hanae Tagami, Yoshinao Nakagawa, Noritaka MizunoAbstract:Ag2[Cr3O(OOCC2H5)6(H2O)3]2[α-SiW12O40] [1] is a nonporous flexible Ionic Crystal composed of 2D-layers of polyoxometalates ([α-SiW12O40]4−) and macrocations ([Cr3O(OOCC2H5)6(H2O)3]+) stacking along the b-axis. The silver ions are located in the vicinity of the oxygen atoms of the polyoxometalates. The sorption amounts of small unsaturated hydrocarbons such as ethylene, propylene, n-butene, acetylene, and methyl acetylene into 1 are comparable to or larger than 1.0 mol mol−1 and large hystereses are observed, while those of paraffins and larger unsaturated hydrocarbons are smaller than the adsorption on the external surface (
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channel selective independent sorption and collection of hydrophilic and hydrophobic molecules by cs2 cr3o oocc2h5 6 h2o 3 2 α siw12o40 Ionic Crystal
Journal of the American Chemical Society, 2006Co-Authors: Chunjie Jiang, Sayaka Uchida, Aldes Lesbani, Ryosuke Kawamoto, Noritaka MizunoAbstract:An Ionic Crystal of Cs2[Cr3O(OOCC2H5)6(H2O)3]2[α-SiW12O40]·4H2O 1a with hydrophilic and hydrophobic channels has been designed and successfully synthesized. The guest-free phase 1b sorbs dichloromethane and water in the hydrophobic and hydrophilic channels, respectively. The rate and equilibrium amount of the dichloromethane sorption into the hydrophobic channel and those of water into the hydrophilic channel were independent of each other. The sorption properties can be applied to the channel-selective sorption and collection of hydrophobic (dichloromethane) and hydrophilic (water) molecules from the mixture.
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amphiphilic guest sorption of k2 cr3o oocc2h5 6 h2o 3 2 α siw12o40 Ionic Crystal
Journal of the American Chemical Society, 2005Co-Authors: Ryosuke Kawamoto, Sayaka Uchida, Noritaka MizunoAbstract:An Ionic Crystal K2[Cr3O(OOCC2H5)6(H2O)3]2[α-SiW12O40]·3H2O (1a) is synthesized by the complexation of a Keggin-type polyoxometalate of [α-SiW12O40]4- with K+ and a macrocation of [Cr3O(OOCC2H5)6(H2O)3]+. Compound 1a possesses both hydrophilic and hydrophobic channels in the Crystal lattice. The 3 mol mol-1 of the water of Crystallization in 1a resides in the hydrophilic channel. The water of Crystallization is removed by the evacuation at 303 K to form the guest-free phase 1b with small changes in the lattice lengths (±0.2 A). The water sorption profile is reproduced by the single rate constant. Therefore, the water sorbed probably resides in the hydrophilic channel. Compound 1b sorbs various kinds of polar organic molecules, and the amounts of ≤C3 alcohols are comparable to or larger than that of water, while chlorocarbons with no hydrogen-bonding ability and nonpolar molecules are excluded. Thus, 1b showed the amphiphilic sorption property. The states of the polar organic molecules sorbed in 1b have be...
Richard Friesner - One of the best experts on this subject based on the ideXlab platform.
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a self consistent charge embedding methodology for ab initio quantum chemical cluster modeling of Ionic solids and surfaces application to the 001 surface of hematite α fe2o3
Journal of Physical Chemistry B, 2002Co-Authors: E R Batista, Richard FriesnerAbstract:To ab initio simulate an Ionic Crystal using a cluster of atoms, one must surround that cluster with point charges. These point charges add the effect of the electrostatic potential of the rest of the Crystal on the electronic structure of the quantum cluster. The value of the point charges has to be chosen to reproduce the Crystal field in the region of the cluster. In this work, a method to compute the necessary point charges is presented. The algorithm to choose the point charges is an extension of the one presented by Derenzo et al. [J. Chem. Phys. 2000, 112, 2074]. The method consists of a self-consistent loop, fitting in each iteration the value of the point charges to reproduce the electrostatic field, calculated from the quantum simulation, in the region of the cluster. This method was then applied to the study of the (001) basal surface of hematite, α-Fe2O3. As the cluster size is systematically increased, it is shown that to fully converge the electrostatic effect on the electronic structure of ...
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A self-consistent charge-embedding methodology for ab initio quantum chemical cluster modeling of Ionic solids and surfaces: Application to the (001) surface of hematite (alpha-Fe2O3)
Journal of Physical Chemistry B, 2002Co-Authors: E R Batista, Richard FriesnerAbstract:To ab initio simulate an Ionic Crystal using a cluster of atoms, one must surround that cluster with point charges. These point charges add the effect of the electrostatic potential of the rest of the Crystal on the electronic structure of the quantum cluster. The value of the point charges has to be chosen to reproduce the Crystal field in the region of the cluster. In this work, a method to compute the necessary point charges is presented. The algorithm to choose the point charges is an extension of the one presented by Derenzo et al. [J. Chem. Phys. 2000, 112, 2074]. The method consists of a self-consistent loop, fitting in each iteration the value of the point charges to reproduce the electrostatic field, calculated from the quantum simulation, in the region of the cluster. This method was then applied to the study of the (001) basal surface of hematite, alpha-Fe2O3. As the cluster size is systematically increased, it is shown that to fully converge the electrostatic effect on the electronic structure of the cluster, clusters of the order of 60 atoms are necessary. As a convergence parameter for the cluster to the bulk behavior, we used the ionization energy of the cluster. In the limit of an infinite cluster, we obtained the work function of hematite to be 5.6 eV.
E R Batista - One of the best experts on this subject based on the ideXlab platform.
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a self consistent charge embedding methodology for ab initio quantum chemical cluster modeling of Ionic solids and surfaces application to the 001 surface of hematite α fe2o3
Journal of Physical Chemistry B, 2002Co-Authors: E R Batista, Richard FriesnerAbstract:To ab initio simulate an Ionic Crystal using a cluster of atoms, one must surround that cluster with point charges. These point charges add the effect of the electrostatic potential of the rest of the Crystal on the electronic structure of the quantum cluster. The value of the point charges has to be chosen to reproduce the Crystal field in the region of the cluster. In this work, a method to compute the necessary point charges is presented. The algorithm to choose the point charges is an extension of the one presented by Derenzo et al. [J. Chem. Phys. 2000, 112, 2074]. The method consists of a self-consistent loop, fitting in each iteration the value of the point charges to reproduce the electrostatic field, calculated from the quantum simulation, in the region of the cluster. This method was then applied to the study of the (001) basal surface of hematite, α-Fe2O3. As the cluster size is systematically increased, it is shown that to fully converge the electrostatic effect on the electronic structure of ...
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A self-consistent charge-embedding methodology for ab initio quantum chemical cluster modeling of Ionic solids and surfaces: Application to the (001) surface of hematite (alpha-Fe2O3)
Journal of Physical Chemistry B, 2002Co-Authors: E R Batista, Richard FriesnerAbstract:To ab initio simulate an Ionic Crystal using a cluster of atoms, one must surround that cluster with point charges. These point charges add the effect of the electrostatic potential of the rest of the Crystal on the electronic structure of the quantum cluster. The value of the point charges has to be chosen to reproduce the Crystal field in the region of the cluster. In this work, a method to compute the necessary point charges is presented. The algorithm to choose the point charges is an extension of the one presented by Derenzo et al. [J. Chem. Phys. 2000, 112, 2074]. The method consists of a self-consistent loop, fitting in each iteration the value of the point charges to reproduce the electrostatic field, calculated from the quantum simulation, in the region of the cluster. This method was then applied to the study of the (001) basal surface of hematite, alpha-Fe2O3. As the cluster size is systematically increased, it is shown that to fully converge the electrostatic effect on the electronic structure of the cluster, clusters of the order of 60 atoms are necessary. As a convergence parameter for the cluster to the bulk behavior, we used the ionization energy of the cluster. In the limit of an infinite cluster, we obtained the work function of hematite to be 5.6 eV.
Teng-ming Chen - One of the best experts on this subject based on the ideXlab platform.
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Fabrication of a Highly Stable White Light-Emitting Diode With Multiple-Layer Colloidal Quantum Dots
IEEE Journal of Selected Topics in Quantum Electronics, 2017Co-Authors: Li-ann Ke, Teng-ming Chen, Yu-ze Chen, Yu-lun ChuehAbstract:A hybrid design by combination of colloidal quantum dots and a traditional light-emitting diode is demonstrated to realize a high-quality white source. The cadmium telluride quantum dots are wrapped in the sodium chloride Ionic Crystal to prevent from environmental corrosion. Three different colors (red, yellow, and green) are picked to provide a better color rendering capability. The single color layer sequence in the package can be properly designed to obtain the best spectrum output. A stable (over 1500 h of continuous operation) and high color rendering index (>92) quantum dot white light-emitting diode can be demonstrated.
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Highly Stable and Efficient Hybrid Quantum Dot Light-Emitting Diodes
IEEE Photonics Journal, 2015Co-Authors: Yin-han Chen, Zong-yi Tu, Teng-ming ChenAbstract:A highly efficient and reliable hybrid quantum dot (QD) light-emitting diode (LED) is demonstrated and analyzed. The CdTe colloidal QDs are embedded in the sodium chloride (NaCl) Ionic Crystal to prevent external wear. The GaN-based ultraviolet (UV) LED is used as the excitation source. The mixture of colloidal QD/NaCl composite and polymer can be filled inside the standard LED package and optically pumped by the UV LED. Two different filling layer designs are fabricated simultaneously for comparative study. Due to extra scattering brought by the sodium chloride grains, the resultant photon conversion efficiency (PCE) can be as high as 72.6% at the medium current level. For the long-term stability assessment, two different UV pumping intensities were set up: One is equivalent to 111 mW/cm 2, and the other is 906 mW/cm 2. With this encapsulation, the stability of the colloidal QD light output over time can be improved, and a prolonged lifetime of 6488 h can be demonstrated under the continuous UV aging condition.
