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1

ONE-DIMENSIONAL COORDINATION POLYMERS - APPLICATIONS TO MATERIAL SCIENCE  

Microsoft Academic Search

Coordination metal complexes with one-dimensional polymeric structures\\u000a have long been investigated as materials with unusual properties.\\u000a Molecular-based ferromagnets, synthetic metallic conductors, non-linear\\u000a optical materials, and ferroelectrics represent several applications of\\u000a low-dimensional coordination polymers. It is possible to modify the bulk\\u000a magnetic, electrical, and optical properties of such materials by\\u000a tailoring the constituent molecules. This review presents recent\\u000a examples of each

CT CHEN

1993-01-01

2

A novel pentanuclear zinc coordination polymer with one-dimensional chain: Synthesis, structure and luminescent property  

NASA Astrophysics Data System (ADS)

One interesting pentanuclear zinc coordination polymer, [Zn5(OH)2(DTBA)4]n (1) (DTBA = 2,2'-dithiobisbenzoic acid) has been synthesized by hydrothermal method, and characterized by X-ray single crystal diffraction, elemental analyses, IR and TGA. The pentanuclear zinc unit exhibits pentagon configuration, which acts as secondary building unit to construct a one-dimensional chain structure by DTBA ligands. As far as we know, this kind of pentagon zinc unit is unprecedented. In addition, upon the excitation at 390 nm, the blue-fluorescence at 448 nm of the compound 1 was observed.

Li, Ya-Min; Xiao, Chang-Yu; Guo, Shao-Shuai; Li, Shu; Cui, Cai-Yan; Li, Jun-Rui

2012-11-01

3

A novel pentanuclear zinc coordination polymer with one-dimensional chain: synthesis, structure and luminescent property.  

PubMed

One interesting pentanuclear zinc coordination polymer, [Zn(5)(OH)(2)(DTBA)(4)](n) (1) (DTBA=2,2'-dithiobisbenzoic acid) has been synthesized by hydrothermal method, and characterized by X-ray single crystal diffraction, elemental analyses, IR and TGA. The pentanuclear zinc unit exhibits pentagon configuration, which acts as secondary building unit to construct a one-dimensional chain structure by DTBA ligands. As far as we know, this kind of pentagon zinc unit is unprecedented. In addition, upon the excitation at 390 nm, the blue-fluorescence at 448 nm of the compound 1 was observed. PMID:22902584

Li, Ya-Min; Xiao, Chang-Yu; Guo, Shao-Shuai; Li, Shu; Cui, Cai-Yan; Li, Jun-Rui

2012-11-01

4

Semiconductive and magnetic one-dimensional coordination polymers of Cu(II) with modified nucleobases.  

PubMed

Four new copper(II) coordination complexes, obtained by reaction of CuX2 (X = acetate or chloride) with thymine-1-acetic acid and uracil-1-propionic acid as ligands, of formulas [Cu(TAcO)2(H2O)4]·4H2O (1), [Cu(TAcO)2(H2O)2]n (2), [Cu3(TAcO)4(H2O)2(OH)2]n·4H2O (3), and [Cu3(UPrO)2Cl2(OH)2(H2O)2]n (4) (TAcOH = thymine-1-acetic acid, UPrOH = uracil-1-propionic acid) are described. While 1 is a discrete complex, 2-4 are one-dimensional coordination polymers. Complexes 2-4 present dc conductivity values between 10(-6) and 10(-9) S/cm(-1). The magnetic behavior of complex 2 is typical for almost isolated Cu(II) metal centers. Moderate-weak antiferromagnetic interactions have been found in complex 3, whereas a combination of strong and weak antiferromagnetic interactions have been found in complex 4. Quantum computational calculations have been done to estimate the individual "J" magnetic coupling constant for each superexchange pathway in complexes 3 and 4. Compounds 2-4 are the first known examples of semiconductor and magnetic coordination polymers containing nucleobases. PMID:24040754

Amo-Ochoa, Pilar; Castillo, Oscar; Gómez-García, Carlos J; Hassanein, Khaled; Verma, Sandeep; Kumar, Jitendra; Zamora, Félix

2013-10-01

5

New one-dimensional imidazole-bridged cadmium(II) coordination polymers—syntheses, crystal structures and photoluminescence  

NASA Astrophysics Data System (ADS)

Two new d 10 metal coordination polymers, [Cd(HIDC)(H 2O) 2] n ( 1) and [Cd(HIDC)(phen)] n ( 2) (H 3IDC=4,5-imidazoledicarboxylic acid, phen=1,10-phenanthroline), have been hydrothermally synthesized and characterized by elemental analysis, IR, TG, and single crystal X-ray diffraction. X-ray single-crystal structural analyses reveal that 1 is a three-dimensional (3D) network featuring one-dimensional honeycomb-like channels constructed from one-dimensional coordination chains via hydrogen bonds, while the 3D supramolecular framework of 2 is formed via ?-? stacking interactions between chains. Moreover, both of them display photoluminescent properties in the blue range at room temperature.

Wang, Xinlong; Qin, Chao; Wang, Enbo; Xu, Lin

2005-07-01

6

Coordination chemistry of 6-thioguanine derivatives with cobalt: toward formation of electrical conductive one-dimensional coordination polymers.  

PubMed

In this work we have synthetized and characterized by X-ray diffraction five cobalt complexes with 6-thioguanine (6-ThioGH), 6-thioguanosine (6-ThioGuoH), or 2'-deoxy-6-thioguanosine (2'-d-6-ThioGuoH) ligands. In all cases, these ligands coordinate to cobalt via N7 and S6 forming a chelate ring. However, independently of reagents ratio, 6-ThioGH provided monodimensional cobalt(II) coordination polymers, in which the 6-ThioG(-) acts as bridging ligand. However, for 2'-d-6-ThioGuoH and 6-ThioGuoH, the structure directing effect of the sugar residue gives rise to mononuclear cobalt complexes which form extensive H-bond interactions to generate 3D supramolecular networks. Furthermore, with 2'-d-6-ThioGuoH the cobalt ion remains in the divalent state, whereas with 6-ThioGuoH oxidation occurs and Co(III) is found. The electrical and magnetic properties of the coordination polymers isolated have been studied and the results discussed with the aid of DFT calculations, in the context of molecular wires. PMID:23594219

Amo-Ochoa, Pilar; Alexandre, Simone S; Hribesh, Samira; Galindo, Miguel A; Castillo, Oscar; Gómez-García, Carlos J; Pike, Andrew R; Soler, José M; Houlton, Andrew; Zamora, Félix; Harrington, Ross W; Clegg, William

2013-05-01

7

Two one-dimensional d¹?-metal coordination polymers based on polydentate Schiff-base ligand: synthesis, crystal structure and luminescent properties.  

PubMed

Two one-dimensional d(10)-metal coordination polymers {[AgL(H(2)O)](2)[AgL(NO(3))](2)(NO(3))(2)L(H(2)O)(2)}(n) (1) and [ZnLCl(2)](n) (2) (L=N,N'-bis-(1-pyridin-4-yl-ethylidene)-hydrazine) have been synthesized and characterized by IR, elemental analysis, TG technique, XRPD and X-ray crystallography. Polymer 1 contains two types of 1D Ag-double-chain units. Ag(1)-double-chain unit is formed by linking two adjacent Ag(1)-L-chains through face-to-face ??? interactions, while Ag(2)-double-chain unit is formed through the combination of coordinating NO(3)(-) anions bridging interactions and ??? interactions between two adjacent Ag(2)-L-chains. Free ligands interact with the adjacent Ag(1)-double-chain units and Ag(2)-double-chain units to form a 3D supramolecular structure through multiform hydrogen bonds. For polymer 2, each ligand acts as a bis-monodentate bridging ligand to bind adjacent Zn(II) centers forming a one-dimensional chain structure. Furthermore, 1D chain is held together with its neighboring ones via CH?? interactions. The luminescent properties of the polymers 1 and 2 were investigated in the solid state at room temperature. PMID:22366615

Niu, Wei-Jia; Wang, Jun-Li; Bai, Yan; Dang, Dong-Bin

2012-06-01

8

A one-dimensional silver(I) coordination polymer with saccharin and pyrazine: synthesis, crystal structure, thermal analysis, FTIR spectra, and DFT studies  

Microsoft Academic Search

A silver(I) complex of saccharinate (sac) with pyrazine (pyz), [Ag(sac)(pyz)]\\u000a n\\u000a , has been synthesized and characterized by elemental analysis, IR, thermal analysis, and single-crystal X-ray diffractometry.\\u000a The complex crystallizes orthorhombic space group Pnma with unit cell parameters of a = 13.0073(9) Å, b = 6.4907(6) Å, c = 13.4007(9) Å, V = 1131.37(15) Å3, and Z = 4. [Ag(sac)(pyz)]\\u000a n\\u000a is a one-dimensional coordination polymer, in which the sac ligand acts as a

Sevim Hamamci; Veysel T. Yilmaz; Sedat Gumus; Orhan Büyükgüngör

2008-01-01

9

One-dimensional manganese coordination polymers composed of polynuclear cluster blocks and polypyridyl linkers: structures and properties.  

PubMed

The synthesis, crystal structures and magnetic properties of five new manganese compounds are reported. These include a linear trinuclear cluster [Mn(II)(3)(O(2)CCHMe(2))(6)(dpa)(2)].2MeCN (1) (dpa = 2,2'-dipyridylamine), a tetranuclear cluster [Mn(II)(2)Mn(III)(2)O(2)(O(2)CCMe(3))(6)(bpy)(2)] (3) (bpy = 2,2'-bipyridine), and chain coordination polymers composed of cluster blocks such as Mn(3), Mn(3)O, and Mn(4)O(2) bridged by 2,2'-bipyrimidine (bpm) or hexamethylentetramine (hmta) ligands to give ([Mn(II)(3)(O(2)CCHMe(2))(6)(bpm)].2EtOH)(n) (2), [Mn(II)(2)Mn(III)(2)O(2)(O(2)CCHMe(2))(6)(bpm)(EtOH)(4)](n) (4), and (([Mn(II)Mn(III)(2)O(O(2)CCHMe(2))(6)(hmta)(2)].EtOH)(n) (5). The magnetic analysis of the compounds was achieved using a combination of vector coupling and full-matrix diagonalization methods. Susceptibility data for compound 1 was fitted using a vector coupling model to give g = 2.02(1) and 2J/k(B) = -5.38(2) K. To model the trimer chain, we used vector coupling for initial values of J(1) and then diagonalization techniques to estimate J(2) to give g = 1.98(1), 2J(1)/k(B) = -3.3(1) K and 2J(2)/k(B) = -1.0(1) K by approximating the system to a dimer of trimers. The analysis of 3 was made difficult by the mixture of polymorphs and the difficulties of a three-J model, while for 4 an analysis was not possible because of the size of the computation and the relative magnitudes of the three couplings. Compound 5 was modeled using the same techniques as 2 to give g = 1.99(1), 2J(1)/k(B) = +32.5(2) K, 2J(2)/k(B) = -16.8(1) K, and 2J(3)/k(B) = +0.4(1) K. The combination of techniques has worked well for compounds 2 and 5 and thus opens up a method of modeling complex chains. PMID:18959375

Baca, Svetlana G; Malaestean, Iurii L; Keene, Tony D; Adams, Harry; Ward, Michael D; Hauser, Jürg; Neels, Antonia; Decurtins, Silvio

2008-12-01

10

One-dimensional coordination polymers made of transition metal–nitronyl nitroxide radical with dicyanoaurate(I) bridges  

Microsoft Academic Search

Three 1-D transition metal–nitronyl nitroxide radical complexes with dicyanoaurate(I) bridges, [M(NIT3py)2][Au(CN)2]2 [NIT3py=2-(3?-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, M=Mn, Co, Zn (1–3)], were synthesized and structurally characterized. Three compounds are all isostructural in monoclinic, C2\\/c space group with Z=4. The [Au(CN)2]? anions link [M(NIT3py)2] units via ?2-bridging mode, leading to a linear coordination chain. The M(II) ion adopts a distorted octahedral geometry with four N atoms

Shu-Ping Wang; Dong-Zhao Gao; You Song; Zhan-Quan Liu; Dai-Zheng Liao; Zong-Hui Jiang; Shi-Ping Yan

2006-01-01

11

One-dimensional and two-dimensional coordination polymers from self-assembling of trinuclear triangular Cu(II) secondary building units.  

PubMed

The reactions of pyrazole (Hpz) with some copper(II) carboxylates in the presence of water yield trinuclear copper derivatives characterized by the triangular core [Cu3mu3-OH)(mu-pz)3(RCOO)2] (R = H, C2H5, C3H7). Copper(II) formate gives [Cu3(mu3-OH)(mu-pz)3(HCOO)2(Hpz)2] (1), whereas copper propionate and butyrate afford [Cu3(mu3-OH)(mu-pz)3(C2H5COO)2(EtOH)] (2) and [Cu3(mu3-OH)(mu-pz)3(C3H7COO)2(MeOH)(H2O)] (3), respectively, both containing solvent molecules coordinated to copper atoms. Magnetic susceptibilities are consistent with a single unpaired electron for each trinuclear unit of 1-3, and EPR measurements indicate that higher spin states, generated by exchange coupling between copper atoms, may be populated at room temperature. Density-functional calculations provide the description of the electronic structures of 1-3, allowing, at the same time, the assignment of their UV-vis absorption spectra. X-ray molecular structure determinations show that triangular trinuclear units of 1 are connected to each other through single formate bridges, forming one-dimensional (1D) zigzag coordination polymers, whereas in 2 and 3, two oxygen atoms of two carboxylate ions doubly bridge two copper atoms of different triangles, thus generating hexanuclear units. Moreover, in 2, two other propionate ions link together two hexanuclear units yielding a 12-membered cycle and giving rise to 1D coordination polymers. The supramolecular assemblies of 1-3 are compared to that of the previously reported trinuclear triangular copper(II) derivative [Cu3(mu3-OH)(mu-pz)3(CH3COO)2(Hpz)] (A), where a two-dimensional (2D) coordination polymer is present. The reactions of 3,5-dimethylpyrazole (Hpz) with copper(II) carboxylates in the same conditions yield 1:2 Cu(RCOO)2/Hpz adducts. PMID:16124805

Casarin, Maurizio; Corvaja, Carlo; Di Nicola, Corrado; Falcomer, Daniele; Franco, Lorenzo; Monari, Magda; Pandolfo, Luciano; Pettinari, Claudio; Piccinelli, Fabio

2005-09-01

12

Thermal, fluorescence, solution and structural studies of one-dimensional Ag I coordination polymer with Ag-Ag and Ag-? interactions  

NASA Astrophysics Data System (ADS)

[Ag 3(?-2-bpc) 3] n · n/2H 2O (2-Hbpc = biphenyl-2-carboxylic acid) ( 1), a new rarely reported Ag I one-dimensional coordination polymer with Ag-Ag and Ag-? interactions, has been synthesized, characterized by elemental analysis and IR spectroscopy and its structure determined by single-crystal X-ray diffraction. The thermal stability of compound 1 was studied by thermal gravimetric (TG) and differential thermal analyses (DTA). The single-crystal X-ray analysis of compound 1 shows that the complex consists of [Ag 3(?-2-bpc) 3] subunits containing of three different Ag environments. Solution- and solid-state luminescent spectra of the ligand 2-Hbpc and compound 1 indicate emission band with the maximum intensity at 360 and 370 nm upon excitation at 300 nm, respectively. The results of studies of the stoichiometry and formation of complex in DMF solution were found to be in support of their solid-state stoichiometry.

Akhbari, Kamran; Morsali, Ali; Zhu, Long-Guan

2008-11-01

13

A chain of changes: influence of noncovalent interactions on the one-dimensional structures of nickel(II) dicarboxylate coordination polymers with chelating aromatic amine ligands.  

PubMed

Five one-dimensional coordination polymers, Ni(BDC)(1,10-phen) (1), Ni(BDC)(2,2'-bipy).0.75H(2)BDC (2), Ni(BDC)(1,10-phen)(H(2)O) (3), Ni(BDC)(1,10-phen)(H(2)O).0.5H(2)BDC (4) and Ni(BDC)(2,2'-bipy)(H(2)O) (5) [where BDC = 1,4-benzenedicarboxylate, 2,2-bipy = 2,2'-bipyridine, and 1,10-phen = 1,10-phenanthroline] that have the same topology but markedly different geometry and packing of the chains have been synthesized by hydrothermal reactions. The results of variations of synthesis conditions and substitutions of 1,10-phenanthroline with 2,2'-bipyridine indicate that incorporation of the coordinating water molecule, which affects the degree of bending of the chain, is primarily influenced by the amine ligand size, suggesting a substantial structural role of aromatic-aromatic interactions and amine ligand steric effects. The incorporation of the guest H(2)BDC molecules was found to be favored by lower pH conditions. Crystal data: 1, monoclinic, space group P2(1)/n, a = 9.5589(6) A, b = 12.6776(8) A, c = 13.5121(9) A, beta = 95.437(1) degrees, Z = 4; 2, monoclinic, space group P2(1)/c, a = 20.532(3) A, b = 21.505(3) A, c = 18.872(3) A, beta = 93.86(1) degrees, Z = 16; 3, triclinic, space group P1, a = 8.618(3) A, b = 10.058(4) A, c = 11.353(4) A, alpha = 115.31(1) degrees, beta = 92.33(1) degrees, gamma = 94.03(1) degrees, Z = 2; 4, triclinic, space group P1, a = 9.7682(12) A, b = 10.6490(13) A, c = 11.2468(14) A, alpha = 76.685(2) degrees, beta = 65.309(2) degrees, gamma = 85.612(2) degrees, Z = 2; 5, monoclinic, space group P2(1)/c, a = 13.9683(9) A, b = 17.4489(11) A, c = 13.7737(9) A, beta = 99.12(1) degrees, Z = 8. PMID:15310214

Go, YongBok; Wang, Xiqu; Anokhina, Ekaterina V; Jacobson, Allan J

2004-08-23

14

One-dimensional copper(II) coordination polymers bridged both by ?- trans-oxamidates and phenyldicarboxylates: Synthesis, crystal structure and DNA binding studies  

Microsoft Academic Search

Two new one-dimensional copper(II) polymers with formulae of [Cu2(H2O)2(dmapox)(ipa)2]n (1) and [Cu2(H2O)2(dmapox)(tpa)2]n (2), where dmapox, ipa and tpa stand for the dianion of N,N?-bis[3-(dimethylamino)propyl]oxamide, isophthalic acid and terephthalic acid respectively, have been synthesized and characterized by elemental analysis, conductivity measurement, IR and electronic spectral studies. The crystal structures of the two complexes have been determined by X-ray single-crystal diffraction. The

Yan-Tuan Li; Zhi-Qiang Liu; Zhi-Yong Wu

2008-01-01

15

A one-dimensional double-chain coordination polymer: [Mn(C12H13NO6S)(C10H8N2)]n.  

PubMed

In the title compound, poly[[(2,2'-bipyridine-kappa(2)N,N')manganese(II)]-micro(3)-N-tosyl-L-glutamato-kappa(4)O,O':O":O"'], [Mn(tsgluo)(bipy)](n), where tsgluo is N-tosyl-L-glutamate (C(12)H(13)NO(6)S) and bipy is 2,2'-bipyridine (C(10)H(8)N(2)), the Mn atoms are octahedrally coordinated by two N atoms of one bipy ligand and by four O atoms of three tsgluo(2-) anions. The gamma-carboxyl group coordinates to the Mn(II) atom in a chelating mode, while the alpha-carboxyl group coordinates in a bidentate-bridging mode. The complex displays a one-dimensional double-chain structure. PMID:15178846

Liang, Fu-Pei; Chen, Man-Sheng; Hu, Rui-Xiang; Chen, Zi-Lu

2004-06-01

16

A one-dimensional cobalt(II) coordination polymer based on 2,4'-oxydibenzoic acid: poly[[[diaquabis[2-(4-carboxyphenoxy)benzoato-?O(1)]cobalt(II)]-?-4,4'-bipyridine-?(2)N:N'] dihydrate].  

PubMed

The reaction of CoSO4 with 2,4-oxydibenzoic acid (H2oba) and 4,4'-bipyridine (bipy) under hydrothermal condition yielded a new one-dimensional cobalt(II) coordination polymer, {[Co(C14H9O5)2(C10H8N2)(H2O)2]·2H2O}n, which was characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, magnetic properties and single-crystal X-ray diffraction. The Co(II) ions are connected by bipy ligands into infinite one-dimensional chains. The Hoba(-) ligands extend out from the two sides of the one-dimensional chain. O-H...O hydrogen bonding extends these chains into a two-dimensional supramolecular architecture. PMID:24992105

Tang, Long; Fu, Feng; Wang, Ji Jiang; Liu, Qi Rui; Zhao, Hang Hang

2014-07-15

17

Solvent-mediated crystal-to-crystal interconversion between discrete lanthanide complexes and one-dimensional coordination polymers and selective sensing for small molecules.  

PubMed

Two isostructural 1D coordination polymers {[Ln(OAc)2(H2O)(OBPT)]·3H2O}n (HOBPT = 4,6-bis(2-pyridyl)-1,3,5-triazin-2-ol, Ln = Eu(3+), 1; Tb(3+), 3) and two discrete complexes [Ln(OAc)2(DMF)2(OBPT)] (Ln = Eu(3+), 2; Tb(3+), 4) have been synthesized in H2O-MeOH or DMF solvents, respectively. Their structures were identified by powder X-ray diffraction. Single-crystal X-ray studies for complexes 1 and 2 revealed that the coordination geometries of the Eu(3+) ions are similar and can be described as a distorted tricapped trigonal prism with six oxygen atoms and three nitrogen atoms. The difference between them is that one aqua ligand and one oxygen atom from the OBPT ligand complete the coordination sphere in complex 1, whereas two DMF molecules complete the coordination sphere in complex 2. Interestingly, the solvent-mediated, reversible crystal-to-crystal transformation between them was achieved by immersing the crystalline samples in the corresponding solvent (H2O or DMF) or by exposing them to solvent vapor. Complex 1 shows a highly selective luminescence enhancement in response to DMF in comparison to that observed in response to other examined solvents such as acetone, ethyl acetate, ethanol, acetonitrile, methanol, and THF. PMID:23697967

Wu, Jin-Ji; Ye, Yu-Xin; Qiu, Ying-Yu; Qiao, Zheng-Ping; Cao, Man-Li; Ye, Bao-Hui

2013-06-01

18

Syntheses and Characterization of New Nickel Coordination Polymers with 4,4?-Dipyridylsulfide. Dynamic Rearrangements of One-Dimensional Chains Responding to External Stimuli: Temperature Variation and Guest Releases/Re-Inclusions  

PubMed Central

Crystal structures and dynamic rearrangements of one-dimensional coordination polymers with 4,4?-dipyridylsulfide (dps) have been studied. Reaction of Ni(NO3)2·6H2O with dps in EtOH yielded [Ni(dps)2(NO3)2] ·EtOH (1), which had channels filled with guest EtOH molecules among the four Ni(dps)2 chains. This coordination polymer reversibly transformed the channel structure responding to temperature variations. Immersion of 1 in m-xylene released guest EtOH molecules to yield a guest-free coordination polymer [Ni(dps)2(NO3)2] (2a), which was also obtained by treatment of Ni(NO3)2·6H2O with dps in MeOH. On the other hand, removal of the guest molecules from 1 upon heating at 130 °C under reduced pressure produced a guest-free coordination polymer [Ni(dps)2(NO3)2] (2b). Although the 2a and 2b guest-free coordination polymers have the same formula, they showed differences in the assembled structures of the one-dimensional chains. Exposure of 2b to EtOH vapor reproduced 1, while 2a did not convert to 1 in a similar reaction. Reaction of Ni(NO3)2·6H2O with dps in acetone provided [Ni(dps)(NO3)2(H2O)] ·Me2CO (4) with no channel structure. When MeOH or acetone was used as a reaction solvent, the [Ni(dps)2(NO3)2] · (guest molecule) type coordination polymer, which was observed in 1, was not formed. Nevertheless, the reaction of Ni(NO3)2·6H2O with dps in MeOH/acetone mixed solution produced [Ni(dps)2(NO3)2]·0.5(MeOH·acetone) (5), which has an isostructural Ni-dps framework to 1.

Kondo, Mitsuru; Takahashi, Hideaki; Watanabe, Hirotaka; Shimizu, Yusuke; Yamanishi, Katsunori; Miyazawa, Makoto; Nishina, Naoko; Ishida, Yutaka; Kawaguchi, Hiroyuki; Uchida, Fumio

2010-01-01

19

Syntheses, structures and magnetic properties of two one-dimensional coordination polymers of cobalt(II) and nickel(II) dicyanamide containing a tridentate N-donor Schiff base  

NASA Astrophysics Data System (ADS)

Two neutral one-dimensional coordination polymers of the type [M(L)(?1,5-dca)(dca)]n [M = Co (1), Ni (2); L = (N,N-diethyl,N'-(pyridin-2-yl)benzylidene)ethane-1,2-diamine; dca = dicyanamide] are isolated through single-pot reactions of a 1:1:2 M ratio of M(OAc)2·4H2O, L and Na(dca) in MeOH solution at room temperature and characterized on the basis of microanalyses, spectroscopic, thermal and other physicochemical results. X-ray structural study reveals that each metal(II) center in both compounds adopts a distorted octahedral geometry with an MN6 chromophore coordinated by three N atoms of the tridentate Schiff base (L) and three nitrile N atoms of one terminal and two single ?1,5 bridged dca units in a meridional alignment; each ?1,5 bridged dca unit connects other neighboring metal centers in a non-ending fashion affording a 1D chain. Variable-temperature magnetic susceptibility measurements of 1 and 2 show weak antiferromagnetic interactions among the metal centers through ?1,5 dca bridges.

Kundu, Subhasish; Roy, Subhasis; Bhar, Kishalay; Ghosh, Rajarshi; Lin, Chia-Her; Ribas, Joan; Ghosh, Barindra Kumar

2013-04-01

20

Synthesis, structure and luminescence behaviour of heptacoordinated one-dimensional coordination polymers of the type [Cd(L)(dca)] n(X) n (L = a pentadentate Schiff base; dca = dicyanamide; X = ClO4-, PF6-)  

NASA Astrophysics Data System (ADS)

Two heptacoordinated one-dimensional coordination polymers of the type [Cd(L)(dca)] n(X) n ( 1 and 2) [L = N, N'-(bis-(pyridin-2-yl)benzylidene)diethylenetriamine; dca = dicyanamide; X = ClO4- ( 1), PF6- ( 2)] have been prepared and characterized on the basis of microanalytical, spectroscopic and other physicochemical properties. Structures of 1 and 2 are solved by single crystal X-ray diffraction measurements. Structural study reveals that in both compounds each cadmium(II) center adopts a distorted pentagonal bipyramidal geometry with a CdN 7 chromophore coordinated by five N atoms of the pentadentate Schiff base and two nitrile N atoms of single bridged dca in ? 1,5 fashion. The polynuclear units in 1 are engaged in weak N-H…O and C-H…O hydrogen bondings with perchlorate ions embedded among the chains to give a 2D sheet structure. In the long-range form, the 1D polymeric chains of 2 pack through N-H…F and C-H…F hydrogen bonds with hexafluorophosphate placed in between chains resulting a 2D continuum. The complexes display intraligand 1(?-??) fluorescence in DMF solutions at room temperature.

Sarkar, Bhola Nath; Bhar, Kishalay; Chattopadhyay, Soumi; Das, Sumitra; Mitra, Partha; Ghosh, Barindra Kumar

21

Molecular nanostamp based on one-dimensional porphyrin polymers.  

PubMed

Surface design with unique functional molecules by a convenient one-pot treatment is an attractive project for the creation of smart molecular devices. We have employed a silane coupling reaction of porphyrin derivatives that form one-dimensional polymer wires on substrates. Our simple one-pot treatment of a substrate with porphyrin has successfully achieved the construction of nanoscale bamboo shoot structures. The nanoscale bamboo shoots on the substrates were characterized by atomic force microscopy (AFM), UV-vis spectra, and X-ray diffraction (XRD) measurements. The uneven and rigid nanoscale structure has been used as a stamp for constructing bamboo shoot structures of fullerene. PMID:23899272

Kanaizuka, Katsuhiko; Izumi, Atsushi; Ishizaki, Manabu; Kon, Hiroki; Togashi, Takanari; Miyake, Ryosuke; Ishida, Takao; Tamura, Ryo; Haga, Masa-aki; Moritani, Youji; Sakamoto, Masatomi; Kurihara, Masato

2013-08-14

22

Optical Nonlinearities in One-Dimensional-Conjugated Polymer Crystals  

Microsoft Academic Search

The one-dimensional electronic delocalization that results from the solid-state polymerization of diacetylenes produces a dramatic enhancement of the optical nonlinearities of these compounds. The third-order susceptibilities of the polymerized crystals reach very high values comparable to those of inorganic semiconductors.

C. Sauteret; J.-P. Hermann; R. Frey; F. Pradère; J. Ducuing; R. H. Baughman; R. R. Chance

1976-01-01

23

One-dimensional conducting polymer nanocomposites: Synthesis, properties and applications  

Microsoft Academic Search

Intrinsically conducting polymers have been studied extensively due to their intriguing electronic and redox properties and numerous potential applications in many fields since their discovery in 1970s. To improve and extend their functions, the fabrication of multi-functionalized conducting polymer nanocomposites has attracted a great deal of attention because of the emergence of nanotechnology. This article presents an overview of the

Xiaofeng Lu; Wanjin Zhang; Ce Wang; Ten-Chin Wen; Yen Wei

2011-01-01

24

One-dimensional polymer Fermi gas at zero temperature  

NASA Astrophysics Data System (ADS)

In this work we study a completely degenerated fermion gas at zero temperature employing a semi-classical approximation obtained from polymer quantum mechanics. Polymer quantum systems are quantum mechanical models quantized in a similar way as in loop quantum gravity. These models allow the study in a simplified way of the discreteness of space present in loop quantum gravity. We obtain the thermodynamic quantities modified by the polymer scale and we note that the corresponding Fermi energy is exactly the same as if one directly polymerizes the momentum pF.

Chacón-Acosta, Guillermo; Hernández, Héctor H.

2013-07-01

25

Brownian-dynamics computer simulations of a one-dimensional polymer model. I. Simple potentials  

SciTech Connect

Brownian Dynamics computer simulation results are presented on a simple one-dimensional polymer model which contains the essential features of rotational angle flexibility. Comparison is made with analytical treatments of the model.

Cook, R.; Livornese, L.L.

1982-11-01

26

A one-dimensional ladder-like six-coordinate cadmium polymer: catena-poly[bis[(S)-2-methylpiperazine-1,4-diium] [bis[trichloridocadmium(II)]-di-?3-chlorido  

PubMed

The crystal structure of the title compound {(C5H14N2)2[Cd2Cl8]}n, (I), consists of hydrogen-bonded 2-methylpiperazinediium (H2MPPA(2+)) cations in the presence of one-dimensional polymeric {[CdCl3(?3-Cl)](2-)}n anions. The Cd(II) centres are hexacoordinated by three terminal chlorides and three bridging chlorides and have a slightly distorted octahedral CdCl3(?3-Cl)3 arrangement. The alternating CdCl6 octahedra form four-membered Cd2Cl2 rings by the sharing of neighbouring Cd-Cl edges to give rise to extended one-dimensional ladder-like chains parallel to the b axis, with a Cd···Cd distance of 4.094 (2) Å and a Cd···Cd···Cd angle of 91.264 (8)°. The H2MPPA(2+) cations crosslink the [CdCl3(?3-Cl)]n chains by the formation of two N-H···Cl hydrogen bonds to each chain, giving rise to one-dimensional ladder-like H2MPPA(2+)-Cl2 hydrogen-bonded chains [graph set R4(2)(14)]. The [CdCl3(?3-Cl)]n chains are interwoven with the H2MPPA(2+)-Cl2 hydrogen-bonded chains, giving rise to a three-dimensional supramolecular network. PMID:24816010

Wu, De-Hong

2014-05-01

27

A tetrahedrally coordinated cobalt(II) aminophosphonate containing one-dimensional channels  

NASA Astrophysics Data System (ADS)

A tetrahedrally coordinated cobalt(II) phosphonate, Co(O 3PCH 2CH 2NH 2), has been synthesized using hydrothermal techniques. X-ray diffraction indicates that this material is a three-dimensional open framework with rings aligned along a single axis forming infinite one-dimensional channels. The framework decomposes just above 400 °C. Magnetic susceptibility data are consistent with weak antiferromagnetic ordering at low temperatures.

Gemmill, William R.; Smith, Mark D.; Reisner, Barbara A.

2005-09-01

28

Electron-Electron Interaction Effects in Quasi-One-Dimensional Conducting Polymers and Related Systems.  

National Technical Information Service (NTIS)

We review recent results on the role of electron-electron (e-e) interactions in quasi-one-dimensional conducting polymers and related systems. Within the Peierls-Hubbard model, the effects of both short-range (on-site U and nearest neighbor V sub 1 ) and ...

D. K. Campbell D. Baeriswyl S. Mazumdar

1986-01-01

29

Poly[[[aqua(2,2'-bipyridine-kappa2N,N')manganese(II)]-mu-croconato-kappa4O,O':O'',O'''] monohydrate]: a one-dimensional coordination polymer connected by hydrophilic-hydrophilic and lipophilic-lipophilic interactions at 135 K.  

PubMed

In the title one-dimensional coordination polymer, {[Mn(C(5)O(5))(C(10)H(8)N(2))(H(2)O)].H(2)O}(n), each Mn(II) ion is seven-coordinated by four O atoms from two croconate ligands, two N atoms from a 2,2'-bipyridine (2,2'-bipy) ligand and one O atom from an aqua ligand. The croconate ligand bridges the Mn(II) ions in a bis-bidentate chelation mode, forming an extended [Mn(C(5)O(5))](n) chain running parallel to the [001] direction, with the lipophilic 2,2'-bipy ligands lying along one side and the hydrophilic water molecules along the opposite side. Coordinated water and solvent water molecules are arranged in the hydrophilic layer, which is characterized by O-H...O hydrogen bonds between croconate ligands. Meanwhile, 2,2'-bipy ligands from adjacent chains partially overlap and exhibit pi-pi interactions to form a lipophilic layer. The hydrophilic and lipophilic layers are arranged alternately to build a layer structure. PMID:20354296

Chen, Hong-Feng; Fang, Qi; Chen, Hong-Yu; Yu, Wen-Tao; Weng, Lin-Hong

2010-04-01

30

Nonlinear optical properties of one-dimensional semiconductors and conjugated polymers  

Microsoft Academic Search

We present a detailed study of the nonlinear optical properties of one-dimensional conjugated polymers and semiconductors. The Bloch wave functions and energies and the dipole transition-matrix elements previously obtained within the tight-binding approximation by linear combination of atomic orbitals (Hückel approximation) were used to calculate the nonlinear optical susceptibilities; the expressions of the lattice were obtained by the Genkin-Mednis approach.

G. P. Agrawal; C. Cojan; C. Flytzanis

1978-01-01

31

Pseudo one-dimensional analysis of polymer electrolyte fuel cell cold-start  

SciTech Connect

This paper investigates the electrochemical kinetics, oxygen transport, and solid water formation in polymer electrolyte fuel cell (PEFC) during cold start. Following [Yo Wang, J. Electrochem. Soc., 154 (2007) B1041-B1048], we develop a pseudo one-dimensional analysis, which enables the evaluation of the impact of ice volume fraction and temperature variations on cell performance during cold-start. The oxygen profile, starvation ice volume fraction, and relevant overpotentials are obtained. This study is valuable for studying the characteristics of PEFC cold-start.

Mukherjee, Partha P [Los Alamos National Laboratory; Mukundan, Rangachary [Los Alamos National Laboratory; Borup, Rodney L [Los Alamos National Laboratory; Wang, Yun [NON LANL; Mishlera, Jeff [NON LANL

2009-01-01

32

Solitons and polarons in quasi-one dimensional conducting polymers and related materials  

SciTech Connect

In recent years it has become increasingly appreciated that fundamentally nonlinear excitations - solitons - play an essential role in an incredible variety of natural systems. These solitons, which frequently exhibit remarkable stability under interactions and perturbations, often dominate the transport, response, or structural properties of the systems in which they occur. In this article, we present an introduction to the solitons that occur in quasi-one-dimensional conducting polymers (synmetals) and related systems. The relevance of this subject to molecular electronic devices is twofold. First, many of these materials have molecular structures similar to possible prototype molecular switches. Second, to understand in detail how a molecular electronic device could work, it is essential to have a broad perspective on the nature of possible excitations in a variety of natural and synthetic molecular materials. 51 references.

Campbell, D.K.

1983-01-01

33

Theory of bipolaron lattices in quasi-one-dimensional conducting polymers  

NASA Astrophysics Data System (ADS)

We present a theory of the bipolaron lattice in the Peierls-distorted system with nondegenerate ground states. First, we obtain an exact solution for the order parameter of a bipolaron lattice in terms of the Weierstrass ? function for the continuum model of Brazovskii and Kirova. Making use of the exact solution, we determine the complete band structure of a bipolaron lattice. In addition to the conduction and valence bands, we find two bipolaron bands symmetrically located about the middle of the Peierls energy gap. We also calculate the electronic density of states and the energy of formation of a bipolaron lattice as a function of the bipolaron density nb. The chemical potential of a bipolaron determines the domain of stability of the lattice as a function of the confinement parameter ?. In the weak-coupling limit (infinite momentum cutoff ?) the bipolaron-bipolaron interaction decays as a repulsive exponential while for finite ? it decays inversely proportional to the distance and is attractive. This yields the possibility of phase separation in doped quasi-one-dimensional conducting polymers with nondegenerate ground states. For higher dopant concentrations we describe a possible first-order phase transition to a metallic phase consisting of an array of polaronlike distortions from a lattice of charged bipolarons. As well, the optical absorption spectrum of a bipolaron lattice is briefly discussed. Our results apply to cis-polyacetylene as well as to a class of heterocyclic compound polymers, namely, polypyrroles, polythiophenes, and their derivatives. Finally, we make contact with recent experiments which study the evolution of ordered phases during the electrochemical doping of polyparaphenylene by alkali atoms and indicate the possibility of a bipolaron lattice.

Saxena, Avadh; Gunton, J. D.

1987-03-01

34

Giant coercivity in a one-dimensional cobalt-radical coordination magnet.  

PubMed

A metal-radical polymer [Co(hfac)2.BPNN] showed a very large coercive field of 52 kOe (4.1 MA m-1) at 6 K, indicating that it is the hardest magnet ever reported. Above 10 K, a soft character appeared, owing to the fast dynamics of magnetization reorientation. PMID:18076178

Ishii, Norio; Okamura, Yoshitomo; Chiba, Susumu; Nogami, Takashi; Ishida, Takayuki

2008-01-01

35

Nonlinear Excitations in Quasi - One-Dimensional Conducting Polymers and Structural Phase Transitions in Two Dimensions  

NASA Astrophysics Data System (ADS)

This thesis consists of two major sections. In the first section we develop the theory of bipolaron lattices in the Peierls distorted quasi-one-dimensional (Q1D) systems with nondegenerate ground states and theoretically consider the device applications of the Q1D conducting polymers. In the second part we study structural phase transitions on semiconductor and vicinal surfaces. In the first part we obtain an exact solution for the order parameter of a bipolaron lattice in terms of the Weierstass zeta function for the continuum model of Brazovskii and Kirova. Making use of this solution, we determine the complete band structure, electronic density of states and the energy of formation of a bipolaron lattice. The possibility of a phase separation in doped conducting polymers as well as a first order phase transition to a polaronic metal is discussed. Next, we theoretically consider the possibility of fabricating Q1D devices such as Q1D p-n junctions, Q1D Schottky barriers, Q1D heterojunctions and Q1D doping superlattices. To this end, we calculate the Fermi level as a function of the Peierls gap and the doping level for those Q1D semiconductors and metals whose excitations include solitons, polarons and bipolarons, in addition to electrons and holes. The photoresponse, optical absorption coefficient and related optical and transport properties are determined. In the second section a Monte Carlo study of the structural phase transitions on the Si (100) surface for both the "(2 x 1)" and "c(2 x 2)" reconstruction families is carried out using the asymmetric dimer model. Second order phase transitions are observed at 250 K and 800 K for these two reconstruction families, respectively. Thermodynamic quantities such as specific heat and susceptibility are computed. Finally, we study structural phase transitions and diffraction on stepped and kinked vicinal surfaces. Second order transitions are identified on the ordered kinked crystal surface within the context of Landau-Lifshitz theory. The transitions are found to belong to one of the following universality classes: Ising, X-Y model with cubic anisotropy and Potts. Exact expressions for the diffraction intensity and the atomic pair correlation function are obtained. The Bragg peaks for the kinked surface are predicted to split into quadruplets.

Saxena, Avadh B.

1987-09-01

36

Electro-optic polymer/silicon hybrid slow light modulator based on one-dimensional photonic crystal waveguides  

NASA Astrophysics Data System (ADS)

An electro-optic (EO) modulator composed of EO polymer/silicon hybrid one-dimensional photonic crystal nanobeam waveguides is proposed and experimentally demonstrated. The optical field of the photonic crystal nanobeam is designed to concentrate at the nanoscale low refractive index EO polymer region. We have demonstrated enhanced EO modulation efficiencies as a result of the slower group velocity in the 100-?m-long photonic crystal nanobeam phase-shifters. The results agree well with the behavior predicted from band dispersion characteristics, indicating that EO polymer/silicon hybrid photonic crystal nanobeam waveguides are an effective platform for realizing extremely small and ultrafast EO modulators with low operational power.

Inoue, Shin-ichiro; Otomo, Akira

2013-10-01

37

A one-dimensional reaction coordinate for identification of transition states from explicit solvent P(fold)-like calculations.  

PubMed

A properly identified transition state ensemble (TSE) in a molecular dynamics (MD) simulation can reveal a tremendous amount about how a protein folds and offer a point of comparison to experimentally derived Phi(F) values, which reflect the degree of structure in these transient states. In one such method of TSE identification, dubbed P(fold), MD simulations of individual protein structures taken from an unfolding trajectory are used to directly assess an input structure's probability of folding before unfolding, and P(fold) is, by definition, 0.5 for the TSE. Other, less computationally intensive methods, such as multidimensional scaling (MDS) of the pairwise root mean-squared deviation (RMSD) matrix of the conformations sampled in a thermal unfolding trajectory, have also been used to identify the TSE. Identification of the TSE is made from the original MD simulation without the need to run further simulations. Here we present a P(fold)-like study and describe methods for identification of the TSE through the derivation of a high fidelity, bounded, one-dimensional reaction coordinate for protein folding. These methods are applied to the engrailed homeodomain. The TSE identified by this approach is essentially identical to the TSE identified previously by MDS of the pairwise RMSD matrix. However, the cost of performing P(fold), or even our reduced P(fold)-like calculations, is at least 36,000 times greater than the MDS method. PMID:17978165

Beck, David A C; Daggett, Valerie

2007-11-15

38

The Scaling Limit of Polymer Pinning Dynamics and a One Dimensional Stefan Freezing Problem  

NASA Astrophysics Data System (ADS)

We consider the stochastic evolution of a 1 + 1-dimensional interface (or polymer) in the presence of a substrate. This stochastic process is a dynamical version of the homogeneous pinning model. We start from a configuration far from equilibrium: a polymer with a non-trivial macroscopic height profile, and look at the evolution of a space-time rescaled interface. In two cases, we prove that this rescaled interface has a scaling limit on the diffusive scale (space rescaled by L in both dimensions and time rescaled by L 2 where L denotes the length of the interface) which we describe. When the interaction with the substrate is such that the system is unpinned at equilibrium, then the scaling limit of the height profile is given by the solution of the heat equation with Dirichlet boundary condition ; when the attraction to the substrate is infinite, the scaling limit is given by a free-boundary problem which belongs to the class of Stefan problems with contracting boundary, also referred to as Stefan freezing problems. In addition, we prove the existence and regularity of the solution to this problem until a maximal time, where the boundaries collide. Our result provides a new rigorous link between Stefan problems and Statistical Mechanics.

Lacoin, Hubert

2014-05-01

39

Photophysics of excitons in quasi-one-dimensional organic semiconductors: Single-walled carbon nanotubes and ? -conjugated polymers  

NASA Astrophysics Data System (ADS)

The nature of the primary photoexcitations in semiconducting single-walled carbon nanotubes (S-SWCNTs) is of strong current interest. We have studied the emission spectra of S-SWCNTs and two different ? -conjugated polymers in solutions and films, and have also performed ultrafast pump-probe spectroscopy on these systems with unprecedented spectral range from 0.1to2.6eV . The emission spectra relative to the absorption bands are very similar in S-SWCNTs and polymers, with redshifted photoluminescence in films showing exciton migration. We also found that the transient excited state spectra of both polymers and SWCNTs contain two prominent photoinduced absorption (PA) bands ( PA1 and PA2 ) that are due to photogenerated excitons; in the polymers these PA bands are correlated with a stimulated emission band, which is absent in the S-SWCNTs. In order to understand the similarities in the PA spectra we have performed theoretical calculations of excited state absorptions in ? -conjugated polymers as well as S-SWCNTs within the same correlated electron Hamiltonian. We find strong similarities in the excitonic energy spectra of these two classes of quasi-one-dimensional materials, although there exist also subtle differences such as the occurrence of dark excitons below the optical excitons in the S-SWCNTs. In the polymers PA1 is an excited state absorption from the optical exciton to a two-photon exciton that occurs below the continuum band threshold. In the S-SWCNTs PA1 occurs from both the optical exciton and the dark exciton, to final states which are close in energy and again below the continuum band threshold. PA1 therefore gives the lower limit of the binding energy of the lowest optical exciton in both ? -conjugated polymers and S-SWCNTs. The binding energy of lowest exciton that belongs to the widest S-SWCNTs with diameters ?1nm in films is 0.3-0.4eV , as determined by both experimental and theoretical methods.

Zhao, H.; Mazumdar, S.; Sheng, C.-X.; Tong, M.; Vardeny, Z. V.

2006-02-01

40

Photophysics of quasi-one-dimensional excitons in pi-conjugated polymers and semiconducting single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

In this work we studied the ultrafast dynamics of photoexcitations in pi-conjugated organic semiconductors and semiconducting single-walled carbon nanotubes (S-NTs), using a low-intensity high-repetition rate laser system in the spectral range from 0.13 to 1.05 eV, and high-intensity low-repletion rate laser system in the spectral range from 1.2 to 2.5 eV, in the time domain from 100 fs to 1 ns. We also measured cw photomodulation (PM) spectroscopy of pi-conjugated polymers and photoluminescence (PL) spectra of both polymers and isolated nanotubes. In polymers, we found that excitons are the primary photoexcitations in single polymer chains. However, polarons and polaron pairs may also be photogenerated at early time in films. We consider this process to be extrinsic in nature, namely, dependent on materials properties, temperatures, excitation photon energies, as well as the quality of films. Both annealed and unannealed thin NT films and D2O solutions of isolated NTs were investigated. Various transient photoinduced bleaching (PB) and photoinduced absorption (PA) bands were observed, which also showed photoinduced dichroism and decay together after taking into account the PB spectral shift. The PL emission shows polarization degree. We therefore conclude that the primary photoexcitations in S-NT are excitons that are confined along the NTs. Prom the average PL polarization degree and the transient polarization memory decay, we estimate the PL lifetime in isolated NTs in solution to be of the order of 500 ps, coupling with the minute PL emission quantum efficiency, which indicates weak radiative transition strength. In S-NTs and pi-polymers, the emission spectra relative to the absorption bands are very similar, as well as transient photoinduced absorption bands (PA) with a low-energy PA1 and a higher-energy PA2 in all cases. Theoretical calculations of excited state absorptions within a correlated pi-electron Hamiltonian show the same excitonic energy spectrum, illustrating the universal features of quasi-one-dimensional excitons in carbon-based pi-conjugated systems. In both cases PA1 gives the lower limit of the binding energy of the lowest optical exciton. The binding energy of lowest exciton belonging to the widest S-NTs with diameters ? 1 nm in films is 0.3-0.4 eV, as well as ˜ 0.9 eV in PPV polymers.

Sheng, Chuanxiang

41

Luminescent mechanochromic porous coordination polymers.  

PubMed

Three 2D luminescent isomeric porous coordination polymers are synthesized and characterized. Their luminescence properties can be modified by grinding and they can act as mechanochromic materials and their properties are probably related to the weak interactions of cuprophilicity and ?-? interactions. PMID:24415360

Wen, Tian; Zhou, Xiao-Ping; Zhang, De-Xiang; Li, Dan

2014-01-13

42

One-dimensional copper(II) polymer with bridging ?- trans-oxamidate and thiocyanate ligands: Synthesis, crystal structure and DNA binding studies  

Microsoft Academic Search

A new one-dimensional copper(II) polymer, [Cu4(dmapox)2(SCN)4(CH3CH2OH)2]n·2nCH3CH2OH, where dmapox is the dianion of N,N?-bis[3-(dimethylamino)propyl]oxamide, was synthesized and characterized by elemental analysis, conductivity measurement, IR and electronic spectral studies. The crystal structure of the copper(II) complex has been determined by X-ray single-crystal diffraction. The complex crystallizes in triclinic, space group P1¯ and exhibits infinite one-dimensional copper(II) polymeric chain bridged both by the

Zhi-Qiang Liu; Man Jiang; Yan-Tuan Li; Zhi-Yong Wu; Jian-Xing Yang

2009-01-01

43

An innovative method for coordinate measuring machine one-dimensional self-calibration with simplified experimental process  

NASA Astrophysics Data System (ADS)

In this paper, an innovative method for CMM (Coordinate Measuring Machine) self-calibration is proposed. In contrast to conventional CMM calibration that relies heavily on a high precision reference standard such as a laser interferometer, the proposed calibration method is based on a low-cost artefact which is fabricated with commercially available precision ball bearings. By optimizing the mathematical model and rearranging the data sampling positions, the experimental process and data analysis can be simplified. In mathematical expression, the samples can be minimized by eliminating the redundant equations among those configured by the experimental data array. The section lengths of the artefact are measured at arranged positions, with which an equation set can be configured to determine the measurement errors at the corresponding positions. With the proposed method, the equation set is short of one equation, which can be supplemented by either measuring the total length of the artefact with a higher-precision CMM or calibrating the single point error at the extreme position with a laser interferometer. In this paper, the latter is selected. With spline interpolation, the error compensation curve can be determined. To verify the proposed method, a simple calibration system was set up on a commercial CMM. Experimental results showed that with the error compensation curve uncertainty of the measurement can be reduced to 50%.

Fang, Cheng; Butler, David Lee

2013-05-01

44

An innovative method for coordinate measuring machine one-dimensional self-calibration with simplified experimental process.  

PubMed

In this paper, an innovative method for CMM (Coordinate Measuring Machine) self-calibration is proposed. In contrast to conventional CMM calibration that relies heavily on a high precision reference standard such as a laser interferometer, the proposed calibration method is based on a low-cost artefact which is fabricated with commercially available precision ball bearings. By optimizing the mathematical model and rearranging the data sampling positions, the experimental process and data analysis can be simplified. In mathematical expression, the samples can be minimized by eliminating the redundant equations among those configured by the experimental data array. The section lengths of the artefact are measured at arranged positions, with which an equation set can be configured to determine the measurement errors at the corresponding positions. With the proposed method, the equation set is short of one equation, which can be supplemented by either measuring the total length of the artefact with a higher-precision CMM or calibrating the single point error at the extreme position with a laser interferometer. In this paper, the latter is selected. With spline interpolation, the error compensation curve can be determined. To verify the proposed method, a simple calibration system was set up on a commercial CMM. Experimental results showed that with the error compensation curve uncertainty of the measurement can be reduced to 50%. PMID:23742585

Fang, Cheng; Butler, David Lee

2013-05-01

45

Universal properties of quasi-one-dimensional excitons in semiconducting single-walled carbon nanotubes and $\\\\pi$-conjugated polymers  

Microsoft Academic Search

The nature of the primary photoexcitations in semiconducting single-walled\\u000acarbon nanotubes (S-SWCNTs) is of strong current interest. We have studied the\\u000aemission spectra of S-SWCNTs and two different $\\\\pi$-conjugated polymers in\\u000asolutions and films, and have also performed ultrafast pump-probe spectroscopy\\u000aon these systems. The emission spectra relative to the absorption bands are\\u000avery similar in S-SWCNTs and polymers, with

H. Zhao; S. Mazumdar; C.-X. Sheng; Z. V. Vardeny

2005-01-01

46

Role of AAO template filling process parameters in controlling the structure of one-dimensional polymer nanoparticles.  

PubMed

Solution template wetting is a common technique used to fabricate elongated polymer nanostructures; however, the parameters controlling the resulting morphology remain unclear. The purpose of this investigation was to elucidate the effects of process variables on the types of nanostructures obtained and to understand the physical mechanisms associated with structure development. 1 wt% polystyrene-THF solutions were infiltrated into commercial and homemade anodized aluminum oxide (AAO) templates. The wetting interaction between the AAO template and the polymer solution was examined through contact angle measurements. In general, for moderate dipping times (<18 h), the morphology of the nanopolymer was rod-like at low molecular weights, while tubes were observed at high molecular weight, even at this low concentration. Nanorods were obtained for all molecular weights for extended dipping times. The data suggest that phase separated layers may grow sequentially from the pore walls and yield nanotubes if the growth is interrupted or produce nanorods for unhindered deposition over long periods. PMID:21852733

Pasquali, M; Liang, J; Shivkumar, S

2011-09-16

47

Monolayer behaviors and LB films of dihydroxo (phthalocyaninato) silicon and its polymerone-dimensional phthalocyaninato-polysiloxanes  

Microsoft Academic Search

A novel rigid-rod polymer, 2,9,16,23-tetra-tetradecanophthalocyaninato polysiloxane and its precursor dihydroxo(2,9,16,23-tetra-tetradecanophthalocyaninato) silicium were prepared. The monolayer behaviors of the compounds at the air–water interface are investigated by means of in situ Brewster angle microscopy and their corresponding ?–A isotherms. The LB films of the compounds are deposited by a horizontal dipping technique and their structures are characterized by electronic absorption spectra.

Peng-lei Chen; Dai-hua Tang; Xiao-bing Wang; Hui Chen; Ming-hua Liu; Jun-bai Li; Xin-hou Liu

2000-01-01

48

Photophysics of excitons in quasi-one-dimensional organic semiconductors: Single-walled carbon nanotubes and pi -conjugated polymers  

Microsoft Academic Search

The nature of the primary photoexcitations in semiconducting single-walled carbon nanotubes (S-SWCNTs) is of strong current interest. We have studied the emission spectra of S-SWCNTs and two different pi -conjugated polymers in solutions and films, and have also performed ultrafast pump-probe spectroscopy on these systems with unprecedented spectral range from 0.1to2.6eV . The emission spectra relative to the absorption bands

H. Zhao; S. Mazumdar; C.-X. Sheng; M. Tong; Z. V. Vardeny

2006-01-01

49

Lanthanide based coordination polymers chill, relax under magnetic field and also fluoresce.  

PubMed

Three lanthanide one-dimensional coordination polymers, obtained using Ln(3+) salts and croconate dianion, were structurally characterized. Magnetic studies reveal that the gadolinium analogue exhibits a large magnetocaloric effect while single-molecule magnet behaviour is observed in the dysprosium analogue. PMID:23715412

Goswami, Soumyabrata; Adhikary, Amit; Jena, Himanshu Sekhar; Konar, Sanjit

2013-07-21

50

How to choose one-dimensional basis functions so that a very efficient multidimensional basis may be extracted from a direct product of the one-dimensional functions: Energy levels of coupled systems with as many as 16 coordinates  

NASA Astrophysics Data System (ADS)

In this paper we propose a scheme for choosing basis functions for quantum dynamics calculations. Direct product bases are frequently used. The number of direct product functions required to converge a spectrum, compute a rate constant, etc., is so large that direct product calculations are impossible for molecules or reacting systems with more than four atoms. It is common to extract a smaller working basis from a huge direct product basis by removing some of the product functions. We advocate a build and prune strategy of this type. The one-dimensional (1D) functions from which we build the direct product basis are chosen to satisfy two conditions: (1) they nearly diagonalize the full Hamiltonian matrix; (2) they minimize off-diagonal matrix elements that couple basis functions with diagonal elements close to those of the energy levels we wish to compute. By imposing these conditions we increase the number of product functions that can be removed from the multidimensional basis without degrading the accuracy of computed energy levels. Two basic types of 1D basis functions are in common use: eigenfunctions of 1D Hamiltonians and discrete variable representation (DVR) functions. Both have advantages and disadvantages. The 1D functions we propose are intermediate between the 1D eigenfunction functions and the DVR functions. If the coupling is very weak, they are very nearly 1D eigenfunction functions. As the strength of the coupling is increased they resemble more closely DVR functions. We assess the usefulness of our basis by applying it to model 6D, 8D, and 16D Hamiltonians with various coupling strengths. We find approximately linear scaling.

Dawes, Richard; Carrington, Tucker

2005-04-01

51

Design of one-dimensional coordination networks from a macrocyclic {3d-4f} single-molecule magnet precursor linked by [W(CN)8]3- anions.  

PubMed

The outcome of 1:1 reactions of the tetranuclear 3d-4f Single Molecule Magnet (SMM) [Cu3Tb(L(Pr))(NO3)2(H2O)]NO3 (1) with (TBA)3[W(CN)8] (TBA = tri-n-butyl ammonium cation, [(n-Bu)3N-H](+)) in dimethylformamide (DMF) is dependent on the crystallization method employed: liquid-liquid diffusion of the reagents together gives {[Cu3Tb(L(Pr))W(CN)8(DMF)4]·(DMF)}n (2) whereas diethyl ether vapor diffusion into the reaction solution gives {[Cu3Tb(L(Pr))W(CN)8(DMF)3(H2O)3]·(DMF)1.5·(H2O)0.5}n (3). Both compounds are obtained as black single crystals and feature one-dimensional (1D) coordination networks (chains) of [1](3+) macrocycles linked by [W(CN)8](3-) anions. The two assemblies differ from a structural point of view. Complex 2 has a stepped arrangement with the linkers bound to the opposite faces of the macrocycle, whereas 3 has a square-wave arrangement due to the linkers binding to the same face of the macrocycle. Both compounds display an antiferromagnetic ground state below 3.5 and 2.4 K with a metamagnetic and antiferromagnetic (T, H) phase diagram for 2 and 3, respectively. Remarkably the slow dynamics of the magnetization of the [1](3+) macrocycle units is preserved in 3 while this property is quenched in 2 because of stronger intra- and interchain magnetic interactions inducing a higher critical temperature. PMID:24224842

Dhers, Sébastien; Feltham, Humphrey L C; Clérac, Rodolphe; Brooker, Sally

2013-12-01

52

A three-dimensional microporous coordination polymer with fluorescent property  

NASA Astrophysics Data System (ADS)

A microporous metal-organic coordination polymer formulated as [Cd 2(btec)(H 2O) 2]·0.8DMF (1), where btec = 1,2,4,5-benzenetetracarboxylate and DMF = N, N-dimethylformamide, has been isolated under solvothermal condition and characterized by elemental analyses, IR, thermal stability analysis, fluorescent spectrum, and single-crystal X-ray diffraction analysis. The framework in 1 possesses a three-dimensional architecture with ordered one-dimensional rhombus channels, the dimensions of channels are approximately 10 Å at the widest and 3 Å at the narrowest spacing considering the van der Waal radii of atoms in the framework running along the a-axis. Furthermore, compound 1 shows intense photoluminescent property at room temperature.

Gao, Chaoying; Liu, Shuxia; Xie, Linhua; Ren, Yuanhang; Cao, Ruige; Cao, Jianfang; Zhao, Xinyu

2008-11-01

53

Synthesis, crystal structure and magnetic properties of a one-dimensional copper(II) polymer bridged by different double end-on azide bridges  

NASA Astrophysics Data System (ADS)

A one-dimensional (1D) copper(II) complex [Cu 3(? 1,1-N 3) 6(dmp) 2] n ( 1) has been synthesized and structurally characterized. The molecular structure of 1 is constructed by trimeric [Cu 3(? 1,1-N 3) 6(dmp) 2] units formed through two double symmetric (basal-to-basal) end-on (EO) azide bridges and the trimeric units are connected further by double asymmetric (basal-to-apical) EO azide bridges, giving 1D chain-like structure. The chains of 1 are linked together by N-H⋯N azide hydrogen bonds and very weak Cu⋯N azide coordination interactions from ?-1,1,3,3-N 3 fashion to form two-dimensional (2D) supramolecular architecture. The magnetic structure can be considered as uniform 1D chain formed by linear trimeric Cu II-Cu II-Cu II units and the dominating magnetic coupling occurs within the trimeric Cu3II unit. The magnetic study shows that the compound exhibits ferromagnetic interactions with Jt = + 8.36(2) cm -1 and Jc = + 0.35(4) cm -1 for intratrimeric and intertrimeric Cu3II unit based on 1D magnetic model, respectively.

Zhang, Li-Fang; Yu, Ming-Ming; Ni, Zhong-Hai; Cui, Ai-Li; Kou, Hui-Zhong

2011-12-01

54

Modular Synthesis of Functional Nanoscale Coordination Polymers  

PubMed Central

The coordination-directed assembly of metal ions and organic bridging ligands has afforded a variety of bulk-scale hybrid materials with promising characteristics for a number of practical applications, such as gas storage and heterogeneous catalysis. Recently, so-called coordination polymers have emerged as a new class of hybrid nanomaterials. Herein, we highlight advances in the syntheses of both amorphous and crystalline nanoscale coordination polymers. We also illustrate how scaling down these materials to the nano-regime has enabled their use in a broad range of applications including catalysis, spin-crossover, templating, biosensing, biomedical imaging, and anticancer drug delivery. These results underscore the exciting opportunities of developing next-generation functional nanomaterials based on molecular components.

Lin, Wenbin; Rieter, William J.; Taylor, Kathryn M. L.

2013-01-01

55

Syntheses, structural analyses and luminescent property of four alkaline-earth coordination polymers  

NASA Astrophysics Data System (ADS)

Four alkaline-earth coordination polymers, [Ba(Pzdc)(H2O)]n (1), [Ba(Pzdc)]n (2), [AgSr(Pzdc)(NO3)(H2O)]n (3), [Ag2Ca(Pzdc)2(H2O)]n (4) (H2Pzdc=2, 3-pyrazinedicarboxylic acid) have been synthesized and characterized by single-crystal X-ray diffraction. Compounds 1 and 2 afford 2D layer networks generated by one-dimensional chains containing the [Ba2O11N] units. Compound 3 is of 2D mixed-metal coordination network formed by one-dimensional chain units, while 4 is of a 3D heterometallic framework. Interestingly, 1 and 2 can undergo reversible SCSC structural transformation upon dehydration/rehydration of coordinated water molecules. In addition, the ?-? stacking interactions dominate fluorescent properties of compounds 1 and 2.

Zhang, Sheng; Qu, Xiao-Ni; Xie, Gang; Wei, Qing; Chen, San-Ping

2014-02-01

56

Responsive lanthanide coordination polymer for hydrogen sulfide.  

PubMed

Metal organic coordination polymers have received great attention because of their flexible compositions and architecture. Here, we report the design and synthesis of a responsive lanthanide coordination polymer (LCP) for hydrogen sulfide (H2S), utilizing self-assembling of biomolecule nucleotide with luminescent terbium ion (Tb(3+)) and sensitizing silver ion (Ag(+)) in aqueous solution. LCP is highly fluorescent due to the inclusion of Ag(+) ions, which sensitized the fluorescence of Tb(3+) ions. H2S can strongly quench the fluorescence of LCP through its high affinity for Ag(+) ions. Such configurated LCP material from initial building blocks showed high sensitivity and selectivity for H2S and was applied to the determination of H2S in human serum. LCP with Tb(3+) ions also has a long fluorescence lifetime, which allows for time-resolved fluorescence assays, possessing particular advantages to probing H2S in biological systems with autofluorescence. PMID:24191713

Liu, Baoxia; Chen, Yang

2013-11-19

57

Homochiral 1D zinc-quitenine coordination polymer with a high dielectric constant.  

PubMed

Heat treatment of a solution of MeOH and water containing the quitenine ligand HQA [HQA = 6-methoxyl-(8S,9R)-cinchonan-9-ol-3-carboxylic acid] and ZnCl2 at 70 degrees C to give the one-dimensional (1D) chain coordination polymer {(HQA)(ZnCl2)(2.5H2O)}n (1). The local coordination geometry around the zinc center in 1 displays a slightly distorted tetrahedron, with the HQA ligand adopting a zwitterionic moiety similar to that found in natural amino acids. Measurements on a powdered sample of 1 reveal a strong second-harmonic-generation response of ca. 20 times larger than that for KDP (KH2PO4). Notably, measurements on the dielectric properties of 1 showed that the 1D chain coordination polymer exhibited a dipolar chain relaxation process and a high dielectric constant (epsilon0= 37.3). PMID:16780300

Tang, Yun-Zhi; Huang, Xue-Feng; Song, Yu-Mei; Hong Chan, Philip Wai; Xiong, Ren-Gen

2006-06-26

58

The One-Dimensional Random Walk  

NSDL National Science Digital Library

Created by authors Gary McGath and Paul Trunfio of Boston University's Center for Polymer Studies, this is the description and instructions for the One-Dimensional Random Walk applet. This Applet relates random coin-flipping to random motion. It strives to show that randomness (coin-flipping) leads to some sort of predictable outcome (the bell-shaped curve).

Mcgath, Gary; Trunfio, Paul

2008-12-30

59

Spontaneous emission control of CdSe/ZnS nanoparticle monolayer in polymer nanosheet waveguide assembled on a one-dimensional silver grating surface.  

PubMed

We present spontaneous emission control of a core-shell CdSe/ZnS nanoparticle array assembled with polymer ultrathin films consisting of polymer nanosheets on a silver grating substrate, which served as a unique and simple photonic cavity. The grating-coupled waveguide modes enabled 10(3) order luminescence enhancement and one-fourth spectral narrowing. The light emission from a CdSe/ZnS nanoparticle array can be controlled by tuning the film thickness of hybrid polymer nanoassemblies, which provides multiple emission performance with good tuning ability from red to green at low-power continuous wave laser excitation (??W). PMID:22260265

Mitsuishi, Masaya; Morita, Shimpei; Tawa, Keiko; Nishii, Junji; Miyashita, Tokuji

2012-02-01

60

One-Dimensional Heat Equation  

NSDL National Science Digital Library

Using Maple or Mathmatica, the learner will study the symbolic form and graphical representation of the approximate solutions of the one-dimensional heat equation with various boundary and initial conditions.

Smith, David

2002-01-12

61

Dynamic self-assembly of coordination polymers in aqueous solution.  

PubMed

The construction of supramolecular polymers has been intensively pursued because the nanostructures formed through weak non-covalent interactions can be triggered by external stimuli leading to smart materials and sensors. Self-assemblies of coordination polymers consisting of metal ions and organic ligands in aqueous solution also provide particular contributions in this area. The main motivation for developing those coordination polymers originates from the value-added combination between metal ions and ligands. This review highlights the recent progress of the dynamic self-assembly of coordination polymers that result from the sophisticated molecular design, towards fabricating stimuli-responsive systems and bio-related materials. Dynamic structural changes and switchable physical properties triggered by various stimuli are summarized. Finally, the outlook for aqueous nanostructures originated from the dynamic self-assembly of coordination polymers is also presented. PMID:24955807

Li, Wen; Kim, Yongju; Li, Jingfang; Lee, Myongsoo

2014-08-01

62

Highly birefringent cyanoaurate coordination polymers: the effect of polarizable C-X bonds (X = Cl, Br).  

PubMed

Four new coordination polymers, Mn(Clterpy)[Au(CN)(2)](2) (Clterpy = 4'-chloro-2,2';6',2''-terpyridine), Mn(Brterpy)[Au(CN)(2)](2) (Brterpy = 4'-bromo-2,2';6',2''-terpyridine), Pb(Clterpy)[Au(CN)(2)](2), and Pb(Brterpy)(mu-OH(2))(0.5)[Au(CN)(2)](2) were synthesized and structurally characterized, and their birefringence values were measured. The supramolecular structures of the two Mn(II) polymers are the same: they form one-dimensional (1D) chains of Mn(Xterpy)[Au(CN)(2)](2) units (X = Cl, Br), each having one bridging and one terminal Au(CN)(2)(-). The Pb(II) analogues form 1D polymers containing chains of Pb(Xterpy)[Au(CN)(2)](+) linked via Au(CN)(2)(-) units. Pb(Brterpy)(mu-OH(2))(0.5)[Au(CN)(2)](2) also contains a bridging water unit. In the plane of the primary crystal growth direction, the birefringence values of the four coordination polymers were found to be 0.378(19), 0.50(3), 0.38(2), and 0.26(3), respectively. The birefringence values are related to the supramolecular structures in terms of maximizing the alignment of the terpyridine-based units and the maximum off-axis positioning of the C-X bonds. With the exception of that for the Pb(Brterpy)(mu-OH(2))(0.5)[Au(CN)(2)](2) polymer, the birefringence values are either as large as or significantly larger than in the related M(2,2';6',2''-terpyridine)[Au(CN)(2)](2) systems. These polymers illustrate the utility of adding polarizable carbon-halogen bonds as a design element in highly birefringent coordination polymers. PMID:19954147

Katz, Michael J; Leznoff, Daniel B

2009-12-30

63

Novel pb and zn coordination polymers: synthesis, molecular structures, and third-order nonlinear optical properties.  

PubMed

Three novel coordination polymers [Pb(bbbm)(2)(NO(3))(2)](n) (bbbm = 1,1'-(1,4-butanediyl)bis-1H-benzimidazole) 1, [Zn(bbbt)(NCS)(2)](n) (bbbt = 1,1'-(1,4-butanediyl)bis-1H-benzotriazole) 2, and [Zn(pbbt)(NCS)(2)](n) (pbbt = 1,1'-(1,3-propylene)bis-1H-benzotriazole) 3 were synthesized and structurally characterized. Polymer 1 exhibits a two-dimensional rhombohedral grid network structure, the dimensions of the grid are 14.274 x 14.274 A, and the diagonal-to-diagonal distances are 24.809 x 14.125 A. Polymer 2 possesses a concavo-convex chain structure different from those of the known one-dimensional polymers, which are linear chain, zigzag chain, helical chain, double-stranded chain, and ladder chain. Polymer 3 exhibits a one-dimensional zigzag chain structure, and these chains were packed as an.ABAB. layered structure. The third-order nonlinear optical (NLO) properties of polymers1, 2, and 3 were determined with a 7-ns pulsed laser at 532 nm. 1 shows strong third-order NLO absorptive and refractive properties, and its alpha(2) and n(2) values were calculated to be 5.8 x 10(-)(9) m W(-)(1) and 4.67 x 10(-)(18) m(2) W(-)(1) in a 3.4 x 10(-)(4) mol dm(-)(3) DMF solution, respectively. Both 2 and 3 exhibit weaker NLO absorption and strong refractive properties, and their n(2) values are 4.53 x 10(-)(18) m(2) W(-)(1) for 2 in a 5.2 x 10(-)(4) mol dm(-)(3) DMF solution and 3.02 x 10(-)(18) m(2) W(-)(1) for 3 in a 4.35 x 10(-)(4) mol dm(-)(3) DMF solution. The chi((3)) values of 1, 2, and 3 were calculated to be 1.67 x 10(-)(11), 1.62 x 10(-)(11), and 1.08 x 10(-)(11) esu, respectively, and the values are larger than those of the reported coordination polymers. We deduce that the valence shell structures of metal ions may have some influence on the strength of NLO properties, and discuss the relationships between the crystal structures of coordination polymers and the observed NLO properties. PMID:12588169

Meng, Xiangru; Song, Yinglin; Hou, Hongwei; Fan, Yaoting; Li, Gang; Zhu, Yu

2003-02-24

64

Nanoscale coordination polymers for anticancer drug delivery  

NASA Astrophysics Data System (ADS)

This dissertation reports the synthesis and characterization of nanoscale coordination polymers (NCPs) for anticancer drug delivery. Nanoparticles have been explored in order to address the limitations of small molecule chemotherapeutics. NCPs have been investigated as drug delivery vehicles as they can exhibit the same beneficial properties as the bulk metal-organic frameworks as well as interesting characteristics that are unique to nanomaterials. Gd-MTX (MTX = methotrexate) NCPs with a MTX loading of 71.6 wt% were synthesized and stabilized by encapsulation within a lipid bilayer containing anisamide (AA), a small molecule that targets sigma receptors which are overexpressed in many cancer tissues. Functionalization with AA allows for targeted delivery and controlled release to cancer cells, as shown by enhanced efficacy against leukemia cells. The NCPs were doped with Ru(bpy)32+ (bpy = 2,2'-bipyridine), and this formulation was utilized as an optical imaging agent by confocal microscopy. NCPs containing the chemotherapeutic pemetrexed (PMX) were synthesized using different binding metals. Zr-based materials could not be stabilized by encapsulation with a lipid bilayer, and Gd-based materials showed that PMX had degraded during synthesis. However, Hf-based NCPs containing 19.7 wt% PMX were stabilized by a lipid coating and showed in vitro efficacy against non-small cell lung cancer (NSCLC) cell lines. Enhanced efficacy was observed for formulations containing AA. Additionally, NCP formulations containing the cisplatin prodrug disuccinatocisplatin were prepared; one of these formulations could be stabilized by encapsulation within a lipid layer. Coating with a lipid layer doped with AA rendered this formulation an active targeting agent. The resulting formulation proved more potent than free cisplatin in NSCLC cell lines. Improved NCP uptake was demonstrated by confocal microscopy and competitive binding assays. Finally, a Pt(IV) oxaliplatin prodrug was synthesized and incorporated in different NCPs using various binding metals. A moderate drug loading of 44.9 wt% was determined for Zr-based NCPs. This drug loading, along with a diameter less than 200 nm, make these particles promising candidates for further stabilization via lipid encapsulation.

Phillips, Rachel Huxford

65

Synthesis and characterization of coordination polymer nanoparticles as radioisotope tracers.  

PubMed

Coordination polymer nanoparticles (NPs) with gamma-emitting nuclide (Au-198), 411keV, 675keV, 822keV and 1087keV were prepared by coordination polymerization of the radioisotope Au(3+) ions and 1,4-bis(imidazole-1-ylmethyl)benzene in an aqueous solution at room temperature for 3h. Here, the radioisotope Au(3+) ions were prepared by dissolution of Au-198 foil, which was prepared by neutron irradiation from the HANARO reactor, in KCN aqueous solution. The successful synthesis of the radioisotope coordination polymer NPs with 5±0.5nm was confirmed via UV-vis spectroscopy, Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectrometry (EDXS), Thermogravimetric analysis (TGA), and Gamma spectroscopy analysis. The synthesized radioisotope coordination polymer NPs can be used as radiotracers in science, engineering, and industrial fields. PMID:24362459

Oh, Min-Seok; Jung, Sung-Hee; Choi, Seong-Ho

2014-02-01

66

Synthesis, crystal structure and luminescence properties of lanthanide coordination polymers with a new semirigid bridging thenylsalicylamide ligand  

NASA Astrophysics Data System (ADS)

Two new lanthanide coordination polymers based on a semirigid bridging thenylsalicylamide ligand {[Ln2L3(NO3)6]·(C4H8O2)2}? were obtained and characterized by elemental analysis, X-ray diffraction, IR and TGA measurements. The two compounds are isostructure and possess one dimensional trapezoid ladder-like chain built up from the connection of isolated LnO3(NO3)3 polyhedra (distorted monocapped antisquare prism) through the ligand. The photoluminescence analysis suggest that there is an efficient ligand-to-Ln(III) energy transfer in Tb(III) complex and the ligand is an efficient "antenna" for Tb(III). From a more general perspective, the results demonstrated herein provide the possibility of controlling the formation of the desired lanthanide coordination structure to enrich the crystal engineering strategy and enlarge the arsenal for developing excellent luminescent lanthanide coordination polymers.

Song, Xue-Qin; Wang, Li; Zhao, Meng-Meng; Wang, Xiao-Run; Peng, Yun-Qiao; Cheng, Guo-Quan

2013-09-01

67

Reactive Polymers: Main Chain Coordination Polymers for Air Separation.  

National Technical Information Service (NTIS)

The objective of this research program was to develop and characterize new air separation membrane materials based upon polymers with tetradentate Schiff-base/Co(II) chelates incorporated in the chain backbone. Many tetradentate Schiff-base/Co(II) chelate...

B. D. Freeman

1994-01-01

68

Homochiral coordination polymers constructed from aminocarboxylate derivates: Effect of bipyridine on the amidation reaction  

NASA Astrophysics Data System (ADS)

Using aminocarboxylate derivates (S)-N-(4-cyanobenzoic)-glutamic acid (denoted as cbg, 1a) and (S)-N-(4-nitrobenzoic)-glutamic acid (denoted as nbg, 1b) as chiral ligands, five new homochiral coordination polymers formulated as [Cu(cbg)(H2O)2]n (3), [Cu(cbop)2(4,4'-bipy)(H2O)]n (4) (cbop=(S)-N-(4-cyanobenzoic)-5-oxoproline, 4,4'-bipy=4,4'-bipyridine), {[Cu(nbop)2(4,4'-bipy)]·4H2O}n (5) (nbop=(S)-N-(4-nitrobenzoic)-5-oxoproline), {[Cd(nbop)2(4,4'-bipy)]·2H2O}n (6), and [Ni(nbop)2(4,4'-bipy)(H2O)2]n (7) have been hydrothermally synthesized and structurally characterized. Single-crystal X-ray diffraction study reveals that the original chirality of aminocarboxylate derivates is maintained in all these complexes. Complexes 3, 4, and 7 are one-dimensional infinite chain coordination polymers, while complexes 5 and 6 possess two-dimensional network structures. In situ cyclization of 1a and 1b was taken place in the formation of complexes 4-7, which may be due to the competition of 4,4'-bipyridine with chiral ligands during the coordination process. Preliminary optical behavior investigation indicates that ligands 1a, 1b, and complexes 6, 7 are nonlinear optical active.

Chen, Jianshan; Sheng, Tianlu; Hu, Shengmin; Xiang, Shengchang; Fu, Ruibiao; Zhu, Qilong; Wu, Xintao

2012-08-01

69

Preparation of silver nanostructure from silver(I) coordination polymer and fabrication of nano silver(I) bromide by reverse micelles technique  

Microsoft Academic Search

A new one-dimensional silver(I) coordination polymer, [Ag(?-bpfb)(NO3)]n (1); bpfb=N,N?-bis(4-pyridylformamide)-1,4-benzene, has been synthesized and characterized by IR, 1H NMR and 13C NMR spectroscopy. The single crystal X-ray data show that the silver(I) 1D coordination polymer grows into a three-dimensional network by hydrogen bonding and ?–? stacking interactions. Compound 1 with nanorod morphology was also prepared by sonochemical method. The cetyltrimethylammonium bromide

Zohreh Rashidi Ranjbar; Ali Morsali

2011-01-01

70

EXAFS study of some coordination polymers of copper  

NASA Astrophysics Data System (ADS)

The EXAFS spectra for (1) azelaic acid bis phenyl hydrazide, (2) azelaic acid bis 2,4 dinitro phenyl hydrazide and (3) sebacic acid bis phenyl hydrazide coordination polymers of copper were obtained using the EXAFS facility of the Daresbury Laboratory. The EXAFS analysis revealed that copper is surrounded by four nitrogen and two oxygen atoms in the first coordination shell, while the second coordination shell consists of two carbon atoms. This information suggests the octahedral geometry for the repeating units of polymeric complexes, in contrast to the square planar geometry previously proposed.

Deshpande, A. P.

1995-02-01

71

Solid-state reactivity and structural transformations involving coordination polymers.  

PubMed

This tutorial review discusses recent literature on coordination polymers and metal-organic frameworks (MOFs) that exhibit solid-state reactivity and structural transformation under various experimental conditions. Removal or exchange of solvents and guest molecules, exposure to reactive vapours, and external stimuli such as heat, light or mechanochemical force cause such structural transformations and these are often manifested by various physical properties such as colour, magnetism, luminescence, chirality, porosity, etc. due to change in coordination number and geometry, dimensionality, interpenetration, etc. More drastic transformations related to the exchange of metal ions, pillar ligands and insertion of additional ligands between the layers have also been demonstrated. The vast area of dynamic behaviour of coordination polymers and their stimuli-responsive properties have also been addressed briefly. PMID:23034597

Kole, Goutam Kumar; Vittal, Jagadese J

2013-02-21

72

Intramolecularly coordinated telluroxane clusters and polymers.  

PubMed

The stoichiometrically controlled chlorination of the diarylditelluride (8-Me(2) NC(10) H(6) Te)(2) with SO(2) Cl(2) afforded the aryltellurinyl chloride 8-Me(2) NC(10) H(6) TeCl (1) and the aryltellurium trichloride 8-Me(2) NC(10) H(6) TeCl(3) (2). Alternatively, 1 was obtained by the reaction of the aryltellurenyl diethyldithiacarbamate 8-Me(2) NC(10) H(6) Te(S(2) CNEt(2) ) with hydrochloric acid. The base hydrolysis of 2 provided the novel telluroxanes (8-Me(2) NC(10) H(6) Te)(2) OCl(4) (3), (8-Me(2) NC(10) H(6) Te)(6) O(5) Cl(8) (4), (8-Me(2) NC(10) H(6) Te)(6) O(8) Cl(2) (5), [(8-Me(2) NC(10) H(6) Te)(2) O(3) ](n) (6) and (8-Me(2) NC(10) H(6) Te)(6) O(8) (OH)(2) (7) depending on the reaction conditions applied. The reaction of 7 with ClTe(OiPr)(3) in the presence of water gave rise to the telluroxane (8-Me(2) NC(10) H(6) Te)(6) Te(2) O(12) Cl(2) (8). The crystal and molecular structures of 1-3 and 5-8 were determined by X-ray crystallography. The telluroxane clusters and polymers 6-8 hold potential as model compounds for alkali tellurite glasses (M(2) O)(x) (TeO(2) )(1-x) (M=Li, Na, K) for which no precise structural data are available. PMID:21226110

Beckmann, Jens; Bolsinger, Jens; Duthie, Andrew

2011-01-17

73

One-dimensional silicone nanofilaments.  

PubMed

A decade ago one-dimensional silicone nanofilaments (1D-SNF) such as fibres and wires were described for the first time. Since then, the exploration of 1D-SNF has led to remarkable advancements with respect to material science and surface science: one-, two- and three-dimensional nanostructures of silicone were unknown before. The discovery of silicone nanostructures marks a turning point in the research on the silicone material at the nanoscale. Coatings made of 1D-SNF are among the most superhydrophobic surfaces known today. They are free of fluorine, can be applied to a large range of technologically important materials and their properties can be modified chemically. This opens the way to many interesting applications such as water harvesting, superoleophobicity, separation of oil and water, patterned wettability and storage and manipulation of data on a surface. Because of their high surface area, coatings consisting of 1D-SNF are used for protein adsorption experiments and as carrier systems for catalytically active nanoparticles. This paper reviews the current knowledge relating to the broad development of 1D-SNF technologies. Common preparation and coating techniques are presented along with a comparison and discussion of the published coating parameters to provide an insight on how these affect the topography of the 1D-SNF or coating. The proposed mechanisms of growth are presented, and their potentials and shortcomings are discussed. We introduce all explored applications and finally identify future prospects and potentials of 1D-SNF with respect to applications in material science and surface science. PMID:24742356

Artus, Georg R J; Seeger, Stefan

2014-07-01

74

Coordination polymer gels with important environmental and biological applications.  

PubMed

Coordination Polymer Gels (CPGs) constitute a subset of solid-like metal ion and bridging organic ligand structures (similar to metal-organic frameworks) that form multi-dimensional networks through a trapped solvent as a result of non-covalent interactions. While physical properties of these gels are similar to conventional high molecular weight organic polymer gels, coordination polymer gel systems are often fully reversible and can be assembled and disassembled in the presence of additional energy (heat, sonication, shaking) to give a solution of solvated gelators. Compared to gels resulting from purely organic self-assembled low molecular weight gelators, metal ions incorporated into the fibrilar networks spanning the bulk solvent can impart CPGs with added functionalities. The solid/liquid nature of the gels allows for species to migrate through the gel system and interact with metals, ligands, and the solvent. Chemosensing, catalysis, fluorescence, and drug-delivery applications are some of the many potential uses for these dynamic systems, taking advantage of the metal ion's coordination, the organic polydentate ligand's orientation and functionality, or a combination of these properties. By fine tuning these systems through metal ion and ligand selection and by directing self-assembly with external stimuli the rational synthesis of practical systems can be envisaged. PMID:23192282

Jung, Jong Hwa; Lee, Ji Ha; Silverman, Julian R; John, George

2013-02-01

75

Homochiral nickel coordination polymers based on salen(Ni) metalloligands: synthesis, structure, and catalytic alkene epoxidation.  

PubMed

One-dimensional (1D) homochiral nickel coordination polymers [Ni(3)(bpdc)(RR-L)(2)·(DMF)](n) (2R, RR-L = (R,R)-(-)-1,2-cyclohexanediamino-N,N'-bis(3-tert-butyl-5-(4-pyridyl)salicylidene), bpdc = 4,4'-biphenyldicarboxylic acid) and [Ni(3)(bpdc)(SS-L)(2)·(DMF)](n) (2S, SS-L = (S,S)-(-)-1,2-cyclohexanediamino-N,N'-bis(3-tert-butyl-5-(4-pyridyl)salicylidene) based on enantiopure pyridyl-functionalized salen(Ni) metalloligand units NiL ((1,2-cyclohexanediamino-N,N'-bis(3-tert-butyl-5-(4-pyridyl)salicylidene))Ni(II)) have been synthesized and characterized by microanalysis, IR spectroscopy, solid-state UV-vis spectroscopy, thermogravimetric analysis (TGA), circular dichroism (CD) spectroscopy, cyclic voltammetric measurement, and powder and single crystal X-ray diffraction. Each NiL as unbridging pendant metalloligand uses one terminal pyridyl group to coordinate achiral unit (nickel and bpdc(2-)) building a helical chain, while the other pyridyl group remains uncoordinated. Both 2R and 2S contain left- and right-handed helical chains made of the achiral building blocks, while the NiL as remote external chiral source is perpendicular to the backbone of the helices. The nickel coordination polymers 2R and 2S containing unsaturated active nickel center in metalloligand NiL can be used as self-supported heterogeneous catalysts. They show catalytic activity comparable with their homogeneous counterpart in alkene epoxidation and exhibit great potential as recyclable catalysts. PMID:21332212

Huang, Yuanbiao; Liu, Tianfu; Lin, Jingxiang; Lü, Jian; Lin, Zujin; Cao, Rong

2011-03-21

76

Syntheses and characterization of two novel cadmium(II) coordination polymers derived from pyridyl substituted terpyridine and diphenate mixed ligands  

NASA Astrophysics Data System (ADS)

Two metal-organic coordination polymers, [Cd(dpa)(pytpy)]·(H 2O) 3 ( 1) and [Cd 3(dpa)(pytpy) 2(SO 4) 2]·(H 2O) 3 ( 2), have been synthesized by the reactions of 4'-(3-pyridyl)-2,2':6',2''-terpyridine (pytpy), diphenic acid (H 2dpa) with Cd(ClO 4) 2·6H 2O and CdSO 4·8/3H 2O, respectively, in the presence of base. Compound 1 is a one-dimensional helical chain, in which (dpa) 2- as bridging ligand is responsible for the formation of the main framework and pytpy as chelating ligand grafts on one side of the helical chain and forms ?-? stacking interactions with adjacent chains. This compound is further extended into a two-dimensional supramolecular framework through hydrogen bonds. Compound 2 is a one-dimensional chain simultaneously composed of bridging neutral organic ligand, bridging anionic organic ligand and bridging anionic inorganic ligand. The (dpa) 2- and sulfate anions connect Cd II atoms into neutral [Cd 3(dpa)(SO 4) 2] subunits and the trinuclear units are bridged by pytpy ligand into one-dimensional double-layer chain. This structure is further extended into two-dimensional layer architecture through face-to-face ?-? interactions.

Gou, Lei; Zhang, Bo; Hu, Huai-Ming; Chen, Xiao-Li; Wang, Bao-Cheng; Wu, Qing-Ran; Qin, Ting; Tang, Zong-Xun

2008-10-01

77

Microporous coordination polymers as efficient sorbents for air dehumidification.  

PubMed

Air drying is a widespread and critical industrial process. Removal of water from air is commonly accomplished by passage through a desiccant such as alumina; modest water capacity and energy intensive regeneration are limitations of currently used sorbents. Microporous coordination polymers (MCPs) are demonstrated here to be efficient desiccants for the dehumidification of air, and a comparison of their capacity, regenerability, and efficiency with commercial activated alumina is conducted. Complete regeneration using dry air with mild heating is achieved. The attainment of high capacity for the adsorption of water coupled to facile regeneration indicates that gas dehumidification may be an important application for MCPs. PMID:24517543

Guo, Ping; Wong-Foy, Antek G; Matzger, Adam J

2014-03-01

78

A new layered Ca-succinate coordination polymer.  

PubMed

A new layered Ca-succinate coordination polymer, poly[?(3)-succinato-calcium(II)], [Ca(C(4)H(5)O(4))](n), was synthesized by reaction of CaCl(2)·2H(2)O and succinic acid in an aqueous medium under hydrothermal microwave conditions. The structure contains infinite layers of edge-sharing calcium pentagonal-bipyramidal polyhedra forming six-membered rings connected through succinate ligands. Such an assembly of inorganic building units is unique for calcium metal-organic framework-type structures. Adjacent layers are packed into a final pseudo-three-dimensional structure through weak C-H···O hydrogen bonds. PMID:22223278

Mazaj, Matjaz; Kaucic, Venceslav; Golobic, Amalija; Logar, Natasa Zabukovec

2012-01-01

79

Pore design of two-dimensional coordination polymers toward selective adsorption.  

PubMed

We have synthesized four porous coordination polymers (PCPs) using Zn(2+), 4,4'-sulfonyldibenzoate (sdb), and four types of dinitrogen linker ligands, 1,4-diazabicyclo[2,2,2]octane (dabco), 1,4-bis(4-pyridyl)benzene (bpb), 3,6-bis(4-pyridyl)-1,2,4,5-tetrazine (bpt), and 4,4'-bipyridyl (bpy). The bent sdb ligands form a rhombic space connected by zinc paddle-wheel units to form a one-dimensional double chain, and each dinitrogen ligand linked the one-dimensional double chains. There are different assembled structures of two-dimensional sheets with the same connectivities between Zn(2+) and the organic ligands. [Zn2(sdb)2(dabco)]n (1) has a noninterpenetrated and noninterdigitated structure, [Zn2(sdb)2(bpb)]n (2) and [Zn2(sdb)2(bpt)]n (3) have interdigitated structures, and [Zn2(sdb)2(bpy)]n (4) has an interpenetrated structure. The length of the dinitrogen ligands dominated their assembled structures and flexibility, which influence the adsorption properties. The flexible frameworks of 2 and 3 provide different stepwise adsorption behaviors for CO2, CH4, C2H6, and C2H4 affected by their pore diameters and the properties of the gases. Their different adsorption properties were revealed by IR spectroscopy and X-ray analysis under a gas atmosphere. The framework of 4 possesses less flexibility and a smaller void space than the others and a negligible amount of CH4 was adsorbed; however, 4 can adsorb either C2H6 or C2H4 through the gate-opening phenomenon. Measurement of the solid-state (2)H NMR was also carried out to investigate the relationship between the framework structure and the dynamics of bpy with regard to the lower flexibility of 4. We have demonstrated a strategy to control the pore size and assembled structures toward selective adsorption properties of PCPs. PMID:23496290

Hijikata, Yuh; Horike, Satoshi; Sugimoto, Masayuki; Inukai, Munehiro; Fukushima, Tomohiro; Kitagawa, Susumu

2013-04-01

80

Spin crossover behavior in a family of iron(II) zigzag chain coordination polymers.  

PubMed

The paper reports the synthesis and detailed characterization of two new Fe(II) compounds: [Fe(pyim)(2)(bpen)](ClO(4))(2).2C(2)H(5)OH (2) and [Fe(pyim)(2)(bpe)](ClO(4))(2).C(2)H(5)OH (3) (pyim = 2-(2-pyridyl)imidazole, bpen = 1,2-bis(4-pyridyl)ethane, and bpe = 1,2-bis(4-pyridyl)ethene). Both compounds and the earlier synthesized [Fe(pyim)(2)(bpy)](ClO(4))(2).2C(2)H(5)OH (1) (bpy = 4,4'-bipyridine) form a family of one-dimensional spin crossover coordination polymers. Variable-temperature magnetic susceptibility measurements and Mössbauer spectroscopy have revealed rather gradual spin transitions centered at 176 and 198 K for 2 and 3, respectively. The fitting of magnetic properties with the regular solution model leads to the enthalpy and entropy of spin transitions and the cooperativity parameter equal to DeltaH = 12.3 kJ mol(-1), DeltaS = 68.5 J mol(-1) K(-1), Gamma = 1.80 kJ mol(-1) for 2 and DeltaH = 13.6 kJ mol(-1), DeltaS = 68.1 J mol(-1) K(-1), Gamma = 2.05 kJ mol(-1) for 3. The crystal structures of 2 and 3, resolved by X-ray diffraction at 293 K, belong to the monoclinic space group C2/c (Z = 4). Both compounds display a one-dimensional infinite zigzag-chain structure. The polymer chains are stacked into two-dimensional sheets through intermolecular pi-interactions. The crystal packing of both compounds encloses two kinds of channels in which the counter ions and ethanol molecules are inserted. The DFT calculations of binuclear fragments extracted from three polymers resulted in the energy gaps between the LS and HS states being ordered as the observed transition temperatures. The influence of bridging ligands in the studied family of compounds was found in the modulation of the energy gap between the LS and HS states, leading to different transition temperatures. PMID:17308673

Matouzenko, Galina S; Perrin, Monique; Le Guennic, Boris; Genre, Caroline; Molnár, Gábor; Bousseksou, Azzedine; Borshch, Serguei A

2007-03-01

81

Determining the coordinate dependence of some components of the cubic susceptibility tensor {chi}-hat{sub yyyy}{sup (3)}(z, {omega}, -{omega}, {omega}, {omega}) of a one-dimensionally inhomogeneous absorbing plate at an arbitrary frequency dispersion  

SciTech Connect

The possibility of unique reconstruction of the spatial profile of the cubic nonlinear susceptibility tensor component {chi}-hat{sub yyyy}{sup (3)}(z, {omega}, -{omega}, {omega}, {omega}) of a one-dimensionally inhomogeneous plate whose medium has a symmetry plane m{sub y} perpendicular to its surface is proved for the first time and the unique reconstruction algorithm is proposed. The amplitude complex coefficients of reflection and transmission (measured in some range of angles of incidence) as well as of conversion of an s-polarised plane signal monochromatic wave into two waves propagating on both sides of the plate make it possible to reconstruct the profile. These two waves result from nonlinear interaction of a signal wave with an intense plane wave incident normally on the plate. All the waves under consideration have the same frequency {omega}, and so its variation helps study the frequency dispersion of the cubic nonlinear susceptibility tensor component {chi}-hat{sub yyyy}{sup (3)}(z, {omega}, -{omega}, {omega}, {omega}). For media with additional symmetry axes 2{sub z}, 4{sub z}, 6{sub z}, or {infinity}{sub z} that are perpendicular to the plate surface, the proposed method can be used to reconstruct the profile and to examine the frequency dispersion of about one third of all independent complex components of the tensor {chi}-hat{sup (3)}. (nonlinear-optics phenomena)

Golubkov, A A [Department of Physics, Advanced Educational and Scientific Center, M. V. Lomonosov Moscow State University, Moscow (Russian Federation); Makarov, Vladimir A [International Laser Center, M. V. Lomonosov Moscow State University, Moscow (Russian Federation)

2010-12-29

82

Basic Physics of One-Dimensional Metals.  

National Technical Information Service (NTIS)

Largely nonmathematical qualitative lectures are given on the basic physics of nearly one-dimensional conductors. The main emphasis is placed on the properties of a purely one-dimensional electron gas. The effects of a real system having interchain coupli...

V. J. Emery

1976-01-01

83

(1-Butyl-4-methyl-pyridinium)[Cu(SCN)2]: a coordination polymer and ionic liquid.  

PubMed

The compound (C4C1py)[Cu(SCN)2], (C4C1py = 1-Butyl-4-methyl-pyridinium), which can be obtained from CuSCN and the ionic liquid (C4C1py)(SCN), turns out to be a new organic-inorganic hybrid material as it qualifies both, as a coordination polymer and an ionic liquid. It features linked [Cu(SCN)2](-) units, in which the thiocyanates bridge the copper ions in a ?1,3-fashion. The resulting one-dimensional chains run along the a?axis, separated by the C4C1py counterions. Powder X-ray diffraction not only confirms the single-crystal X-ray structure solution but proves the reformation of the coordination polymer from an isotropic melt. However, the materials shows a complex thermal behavior often encountered for ionic liquids such as a strong tendency to form a supercooled melt. At a relatively high cooling rate, glass formation is observed. When heating this melt in differential scanning calorimetry (DSC) and temperature-dependent polarizing optical microscopy (POM), investigations reveal the existence of a less thermodynamically stable crystalline polymorph. Raman measurements conducted at 10 and 100?°C point towards the formation of polyanionic chain fragments in the melt. Solid-state UV/Vis spectroscopy shows a broad absorption band around 18,870?cm(-1) (530?nm) and another strong one below 20,000?cm(-1) (<500?nm). The latter is attributed to the d(Cu(I))??*(SCN)-MLCT (metal-to-ligand charge transfer) transition within the coordination polymer yielding an energy gap of 2.4?eV. At room temperature and upon irradiation with UV light, the material shows a weak fluorescence band at 15,870?cm(-1) (630?nm) with a quantum efficiency of 0.90(2)?% and a lifetime of 131(2)?ns. Upon lowering the temperature, the luminescence intensity strongly increases. Simultaneously, the band around 450?nm in the excitation spectrum decreases. PMID:24644064

Spielberg, Eike T; Edengeiser, Eugen; Mallick, Bert; Havenith, Martina; Mudring, Anja-Verena

2014-04-25

84

Solid-state chemistry of metal coordination polymers  

NASA Astrophysics Data System (ADS)

The research described in this thesis centers on the investigation of the solid-state and structural chemistry of metal coordination polymers. In Chapter II, the irradiation of solid bis(trans-2-butenoato)calcium (1a) with sp{60}Co gamma-rays leads to conversion of 1a to the calcium salt of cis, trans-nepetic acid (2a) in 7.6% yield (based on recovered 1a). The structure of the acidified product 2b was established by the identity of the sp1H and sp{13}C NMR spectra with those of an authentic sample. The cyclodimerization process providing 2 exhibits several remarkable characteristics. Since recovered bis(trans-2-butenoato)calcium may be recycled, the reaction is an efficient, chemo- and stereospecific, solid-state synthesis of a small molecule using ionizing radiation. Cyclodimerization of trans-2-butenoate in solution or in the solid state is unprecedented. Nepetate 2a forms in 76% yield at 10% conversion as established by NMR, GC and GC/MS data. In order to establish whether the intermolecular orientation and distances suggest that this process might be topochemical, an X-ray structure determination was carried out on single crystals of 1. Calcium trans-2-butenoate is a two-dimensional coordination polymer. Each Casp{2+} ion occupies a site of crystallographic Csb2 symmetry; the dihedral angle between adjacent pairs of butenoate planes in this structure is 14.4sp°. Short contacts arise between pairs of 2-butenoate moieties coordinated to a single calcium ion. The product is not the diastereomer predicted from the ground-state crystal structure. A mechanism consistent with the production of the cis, trans-nepetate has been proposed. The successful characterization of reactant and product materials promises to clarify the relationship between ground-state crystal structure and product stereochemistry in radiation-induced solid-state reactions. In Chapter III and IV, the crystal structures of La, Eu, Pr, and Gd(III) complexes of the trans-cinnamate ligand are all isomorphous (space group R3c). On the other hand, Y and Er complexes of the trans-cinnamate ion and the trans-alpha-methylcinnamate ion were isomorphous; these complexes crystallized in space groups P2sb1 and P2sb1/a (a non-standard setting of space group P2sb1/c), respectively. All of the trans-cinnamate complexes are polar, linear coordination polymers, while the alpha-methylcinnamates are monomeric. (Abstract shortened by UMI.)

Cho, Tae Hyung

85

A new two-dimensional manganese(II) coordination polymer based on thiophene-3,4-dicarboxylic acid.  

PubMed

A novel manganese coordination polymer, poly[(?5-thiophene-3,4-dicarboxylato)manganese(II)], [Mn(C6H2O4S)]n, was synthesized hydrothermally using 3,4-thiophenedicarboxylate (3,4-tdc(2-)) as the organic linker. The asymmetric unit of the complex contains an Mn(2+) cation and one half of a deprotonated 3,4-tdc(2-) anion, both residing on a twofold axis. Each Mn(2+) centre is six-coordinated by O atoms of bridging/chelating carboxylate groups from five 3,4-tdc(2-) anions, forming a slightly distorted octahedron. The Mn(2+) centres are bridged by 3,4-tdc(2-) anions to give an infinite two-dimensional layer which incorporates one-dimensional Mn-O gridlike chains, and in which the 3,4-tdc(2-) anion adopts a novel hexadentate chelating and ?5-bridging coordination mode. The fully deprotonated 3,4-tdc(2-) anion exhibits unexpected efficiency as a ligand towards the Mn(2+) centres, which it coordinates through all of its carboxylate O atoms to provide the novel coordination mode. The IR spectrum of the complex is also reported. PMID:24992118

Wang, Gui Xia; Shang, Li Li; Li, Zhao Hao; Zhao, Bang Tun

2014-07-15

86

Self-assembly of fluorescent and magnetic Fe3O4@coordination polymer nanochains.  

PubMed

Fluorescent and magnetic Fe3O4@coordination polymer (Fe3O4@CP) nanochains are synthesized via a simple one-pot solvothermal reaction of magnetite (Fe3O4) and coordination polymer precursors in the presence of an external magnetic field. The shell thickness within Fe3O4@CPs was easily regulated by varying the amounts of coordination polymer precursors used during the reaction. PMID:24889781

Kim, Yoona; Choi, Young Soo; Lee, Hee Jung; Yoon, Hayoung; Kim, Young Keun; Oh, Moonhyun

2014-06-19

87

One-dimensional inverse thermoelasticity problems  

SciTech Connect

The unique solvability of two one-dimensional inverse problems on determining the coefficients of thermoelasticity equations is established; the solution algorithm for these problems is indicated and numerical calculations are given.

Bakhyshev, Sh.M. [State Pedagogical Institute, Gyandzha (Russian Federation)

1994-01-01

88

Conductivity of One-Dimensional Interacting Fermions.  

National Technical Information Service (NTIS)

Using an exactly soluble model, the decay rate of a current-carrying state of one-dimensional fermions is calculated in the presence of random scatterers at finite temperature and the dc conductivity thereby inferred. (Modified author abstract)

D. C. Mattis

1974-01-01

89

One-Dimensional Czedli-Type Islands  

ERIC Educational Resources Information Center

The notion of an island has surfaced in recent algebra and coding theory research. Discrete versions provide interesting combinatorial problems. This paper presents the one-dimensional case with finitely many heights, a topic convenient for student research.

Horvath, Eszter K.; Mader, Attila; Tepavcevic, Andreja

2011-01-01

90

Factorizations of one-dimensional classical systems  

SciTech Connect

A class of one-dimensional classical systems is characterized from an algebraic point of view. The Hamiltonians of these systems are factorized in terms of two functions that together with the Hamiltonian itself close a Poisson algebra. These two functions lead directly to two time-dependent integrals of motion from which the phase motions are derived algebraically. The systems so obtained constitute the classical analogues of the well known factorizable one-dimensional quantum mechanical systems.

Kuru, Senguel [Departamento de Fisica Teorica, Atomica y Optica, Universidad de Valladolid, 47071 Valladolid (Spain); Department of Physics, Faculty of Science, Ankara University, 06100 Ankara (Turkey); Negro, Javier [Departamento de Fisica Teorica, Atomica y Optica, Universidad de Valladolid, 47071 Valladolid (Spain)], E-mail: jnegro@fta.uva.es

2008-02-15

91

Nanoscale coordination polymers exhibiting luminescence properties and NMR relaxivity.  

PubMed

This article presents the first example of ultra-small (3-4 nm) magneto-luminescent cyano-bridged coordination polymer nanoparticles Ln0.33(3+)Gdx3+/[Mo(CN)8]3- (Ln=Eu (x=0.34), Tb (x=0.35)) enwrapped by a natural biocompatible polymer chitosan. The aqueous colloidal solutions of these nanoparticles present a luminescence characteristic of the corresponding lanthanides (5D0?7F0-4 (Eu3+) or the 5D4?7F6-2 (Tb3+)) under UV excitation and a green luminescence of the chitosan shell under excitation in the visible region. Magnetic Resonance Imaging (MRI) efficiency, i.e. the nuclear relaxivity, measurements performed for Ln0.33(3+)Gdx3+/[Mo(CN)8]3- nanoparticles show r1p and r2p relaxivities slightly higher than or comparable to the ones of the commercial paramagnetic compounds Gd-DTPA® or Omniscan® indicating that our samples may potentially be considered as a positive contrast agent for MRI. The in vitro studies performed on these nanoparticles show that they maybe internalized into human cancer and normal cells and well detected by fluorescence at the single cell level. They present high stability even at low pH and lack of cytotoxicity both in human cancer and normal cells. PMID:21258695

Chelebaeva, Elena; Larionova, Joulia; Guari, Yannick; Ferreira, Rute A S; Carlos, Luis D; Trifonov, Alexander A; Kalaivani, Thangavel; Lascialfari, Alessandro; Guérin, Christian; Molvinger, Karine; Datas, Lucien; Maynadier, Marie; Gary-Bobo, Magali; Garcia, Marcel

2011-03-01

92

Bi[NC{sub 5}H{sub 3}(CO{sub 2}){sub 2}](OH{sub 2}){sub x}F (x=1 and 2): New one-dimensional Bi-coordination materials-Reversible hydration and topotactic decomposition to {alpha}-Bi{sub 2}O{sub 3}  

SciTech Connect

Two one-dimensional bismuth-coordination materials, Bi[NC{sub 5}H{sub 3}(CO{sub 2}){sub 2}](OH{sub 2}){sub x}F (x=1 and 2), have been synthesized by hydrothermal reactions using Bi{sub 2}O{sub 3}, 2,6-NC{sub 5}H{sub 3}(CO{sub 2}H){sub 2}, HF, and water at 180 Degree-Sign C. Structures of the two materials were determined by single-crystal X-ray diffraction. Although they have different crystal structures, both Bi-organic materials shared a common structural motif, a one-dimensional chain structure consisting of Bi{sup 3+} cations and pyridine dicarboxylate linkers. Detailed structural analyses include infrared spectroscopy, thermogravimetric analysis, and reversible hydration reactions for the coordinated water molecules were reported. Also, thermal decomposition of the rod-shaped Bi[NC{sub 5}H{sub 3}(CO{sub 2}){sub 2}](OH{sub 2})F single crystals at 800 Degree-Sign C led to {alpha}-Bi{sub 2}O{sub 3} that maintained the same morphology of the original crystals. - Graphical abstract: Calcination of the Bi[NC{sub 5}H{sub 3}(CO{sub 2}){sub 2}](OH{sub 2})F single crystals at 800 Degree-Sign C results in the {alpha}-Bi{sub 2}O{sub 3} rods that maintain the original morphology of the crystals. Highlights: Black-Right-Pointing-Pointer Synthesis of one-dimensional chain Bi-organic frameworks. Black-Right-Pointing-Pointer Reversible hydration reactions of Bi[NC{sub 5}H{sub 3}(CO{sub 2}){sub 2}](OH{sub 2})F. Black-Right-Pointing-Pointer Topotactic decomposition maintaining the same morphology of the original crystals.

Jeon, Hye Rim [Department of Chemistry Education, Chung-Ang University, Seoul 156-756 (Korea, Republic of); Lee, Dong Woo [Department of Chemistry, Chung-Ang University, Seoul 156-756 (Korea, Republic of); Ok, Kang Min, E-mail: kmok@cau.ac.kr [Department of Chemistry, Chung-Ang University, Seoul 156-756 (Korea, Republic of)

2012-03-15

93

Two Cu(II) coordination polymers with single- and double-zigzag chains constructed from 4,4?-(dihydroxymethylene)dibenzoic acid  

NASA Astrophysics Data System (ADS)

Two intriguing one-dimensional coordination polymers, [Cu2(dhmdb)2(H2O)2]?6H2O (1) and Cu(dhmdb)(1,10-phen) (2), have been hydrothermally synthesized and structurally characterized through exploring a new semi-rigid V-type dicarboxylate ligand with hydroxyl groups, 4,4'-(dihydroxymethylene)dibenzoic acid (H2dhmdb). Complexes 1 and 2 display double- and single-zigzag chain structures, respectively, which further result in two-dimensional supramolecular networks by O-H⋯O hydrogen-bonds and ?⋯? stacking interactions. The network of 1 possesses one-dimensional rhombic channels along c axis with the size of about 8 × 8 Å. The phase purity and thermal stability of 1 and 2 have also been investigated.

Qin, Lan; Xu, Lan-Ping; Zhao, Wen-Na; Han, Lei

2013-08-01

94

A silver(i) coordinated phenanthroline-based polymer with high ethylene/ethane adsorption selectivity.  

PubMed

We report a non-porous silver(i) coordinated phenanthroline-based polymer, which exhibits a high ideal ethylene/ethane adsorption selectivity (15/1) and high ethylene uptake (5.0 mmol g(-1)) at ambient temperature and pressure. Both silver(i) coordination and polymer structures are important for the high uptake of ethylene. PMID:24752375

Yu, Chao; Cowan, Matthew G; Noble, Richard D; Zhang, Wei

2014-06-01

95

One dimensionality and spectroscopy in carbon nanotubes  

NASA Astrophysics Data System (ADS)

Unlike regular three-dimensional solids two of a nanotube dimensions are confined and quantized. Bulk samples consist of irregular networks of merging and splitting bundles of parallel tubes. On a local scale, nanotubes are at the same time one-dimensional crystals and two-dimensional quantum rings. They have attracted extensive studies on individual aspects in their electronic and optical properties [1]. The current contribution aims at bridging the fundamental physical concepts behind carbon nanotubes to their unique spectroscopic signatures in optical absorption, luminescence, Raman and electron energy loss spectroscopy. The aim is not to compete with the local depth of a focused review, but to briefly convey the physical concept and related spectroscopic signatures of one-dimensionality. Indirect signatures are the manifold appearances of van Hove singularities in their optical transitions. Direct probes of one-dimensionality unveil the confined momentum space, which manifests in the distinction of localized and propagating excitations.

Kramberger, C.

2013-08-01

96

Copper(I) coordination polymers of 2,2'-dipyridylamine derivatives: syntheses, structures, and luminescence.  

PubMed

Reactions of CuX (X = Br(-), I(-) or CN(-)) with various types of 2,2'-dipyridylamine (dpa) derivatives have been performed via a hydrothermal-solvothermal method and the products have been structurally characterized by X-ray crystallography. Four ligands with different coordination motifs were employed in the reactions, including angular N,N,N',N'-tetra(2-pyridyl)-2,6-pyridinediamine (tppda); linear N,N,N',N'-tetra(2-pyridyl)-1,4-phenylenediamine (tppa) and N,N,N',N'-tetra(2-pyridyl)biphenyl-4,4'-diamine (tpbpa); and star-shaped tris-[4-(2,2'-dipyridylamino)-phenyl]amine (tdpa), which yielded eight copper(I) complexes exhibiting different stoichiometries of Cu-dpa and variable coordination modes of dpa. The compound [Cu(2)(tppda)(?-I)(2)](n) (1) forms a one dimensional (1D) coordination polymer exclusively through double ?(2)-I bridges, which arranges to two dimensional (2D) metal-organic frameworks (MOFs) via the face-to-face ?···? stacking interactions from pyridyl rings. The compound [Cu(6)(tppa)(?(3)-Br)(6)](n) (2) forms a 2D network linked through multiple ?(3)-Br bridges. The compound [Cu(2)(tppa)(?-CN)(2)](n) (3) is also a 2D MOF containing 1D (CuCN)(n) chains. The compounds [Cu(tpbpa)Br](n) (4) and [Cu(4)(tpbpa)(2)(?-I)(4)](n) (5) display two different 1D assemblies: a zig-zag chain for 4 and a linear structure for 5. The compound [Cu(4)(tpbpa)(?-CN)(4)](n) (6) shows a pseudo-4,8(2) topological net, while the compound [Cu(8)(tpbpa)(?-CN)(8)](n)·2nH(2)O (7) exhibits a three-dimensional (3D) framework containing a ···PM··· double helical structure, although both of them contain (CuCN)(n) chains. The compound [Cu(2)(tdpa)(?-I)(2)](n) (8) is a zig-zag chain based on the star-shaped molecule tpda, in which one of three dpa-arms is free of coordination to metal ions. All complexes exhibit luminescence in the solid state. PMID:22415529

Ni, Jia; Wei, Kai-Ju; Min, Yuanzeng; Chen, Yaowen; Zhan, Shunze; Li, Dan; Liu, Yangzhong

2012-05-01

97

Extended information in one-dimensional maps  

NASA Astrophysics Data System (ADS)

An information theoretical structure of one-dimensional maps is investigated by regarding the maps as a “channel” rather than a “source”. Computing various mutual information numerically for one-dimensional dynamical systems, we can observe directly the movement of information as to initial conditions. One feature of information theoretical structure emerged from this computation is such that initially localized information spreads over whole system as time passes. Two groups of maps which are contrasting with each other concerning this feature exhibit a striking difference in their transmission ability of information when coupled to form a linear chain.

Matsumoto, Kenji; Tsuda, Ichiro

1987-05-01

98

Observing solitons in one dimensional magnetic systems  

SciTech Connect

Classical models of one dimensional magnetic systems show that in addition to the linear spin wave excitations, there should exist localized, large amplitude excitations, that can move along the chains while retaining their integrity. It is expected that these excitations, solitons, exist in real materials. The progress that has been made to date in observing solitons in one dimensional magnets by means of neutron scattering, and the difficulties that still remain in unambiguously identifying the soliton contributions to S(q,..omega..) are discussed.

Reiter, G.

1981-01-01

99

One-Dimensional Optical Wave Turbulence  

Microsoft Academic Search

We present a review of the latest developments in one-dimensional (1D) optical wave turbulence. We describe theory, numerics and experimental observations for a 1D optical system. This system is described by two coupled nonlinear equations, which we explore within two wave limits allowing for the expression of the evolution of the complex amplitude in a single dynamical equation. We consider

Jason Laurie; Umberto Bortolozzo; Sergey Nazarenko; Stefania Residori

2011-01-01

100

One-Dimensional Oscillator in a Box  

ERIC Educational Resources Information Center

We discuss a quantum-mechanical model of two particles that interact by means of a harmonic potential and are confined to a one-dimensional box with impenetrable walls. We apply perturbation theory to the cases of different and equal masses and analyse the symmetry of the states in the latter case. We compare the approximate perturbation results…

Amore, Paolo; Fernandez, Francisco M.

2010-01-01

101

New One-Dimensional Quantum Well Structure.  

National Technical Information Service (NTIS)

A new one dimensional quantum well structure is proposed. The structure is created by converting one side of the potential barrier of an asymmetric quantum well into a periodically indented potential. Both the electron and hole states are confined in the ...

Y. C. Chang L. L. Chang L. Esaki

1985-01-01

102

Phonon spectra in one-dimensional quasicrystals  

Microsoft Academic Search

The propagation of phonons in one-dimensional quasicrystals is investigated. We use the projection method which has been recently proposed to generate almost periodic tilings of the line. We define a natural Laplace operator on these structures, which models phonon (and also tight-binding electron) propagation. The selfsimilarity properties of the spectrum are discussed, as well as some characteristic features of the

J. M. Luck; D. Petritis

1986-01-01

103

Resistance of one-dimensional quasicrystals  

Microsoft Academic Search

One-dimensional quasiperiodic systems are often based on an inflation rule giving rise to a recursion formula on the transfer matrices. It is shown in a general setting, that the norm growth of these matrices can be evaluated. A consequence is, for instance, a purely critical regime (namely polynomial bounds in function of the sample size) for the electrical resistance, when

B. Iochum; L. Raymond; D. Testard

1992-01-01

104

The One-Dimensional Wave Equation  

NSDL National Science Digital Library

Created by Lang Moore for the Connected Curriculum Project, the purpose of this module is to study solutions of initial/boundary value problems for the one-dimensional wave equation. This is one of a much larger set of learning modules hosted by Duke University.

Moore, Lang

2010-08-19

105

One-dimensional localization with correlated disorder  

SciTech Connect

A one-dimensional tight-binding model with correlated disorder is studied. The energy dependence of the localization length and the density of states at different correlation lengths and strengths of the disorder are determined. The results show that the localization length increases with increasing correlation lengths, but in addition, a nonmonotonic energy dependence is found. The energy level statistics is also studied.

Soukoulis, C.M. (Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States)); Velgakis, M.J. (School of Engineering, Science Department, University of Patras, 26110 Patras (Greece)); Economou, E.N. (Research Center of Crete, P. O. Box 1527, 71110 Heraklion, Crete (Greece) Department of Physics, University of Crete, 71110 Heraklion, Crete (Greece))

1994-08-15

106

Mesoscopic architectures of porous coordination polymers fabricated by pseudomorphic replication  

NASA Astrophysics Data System (ADS)

The spatial organization of porous coordination polymer (PCP) crystals into higher-order structures is critical for their integration into separation systems, heterogeneous catalysts, ion/electron transport and photonic devices. Here, we demonstrate a rapid method to spatially control the nucleation site, leading to the formation of mesoscopic architecture made of PCPs, in both two and three dimensions. Inspired by geological processes, this method relies on the morphological replacement of a shaped sacrificial metal oxide used both as a metal source and as an ‘architecture-directing agent’ by an analogous PCP architecture. Spatiotemporal harmonization of the metal oxide dissolution and the PCP crystallization allowed the preservation of very fine mineral morphological details of periodic alumina inverse opal structures. The replication of randomly structured alumina aerogels resulted in a PCP architecture with hierarchical porosity in which the hydrophobic micropores of the PCP and the mesopores/macropores inherited from the parent aerogels synergistically enhanced the material’s selectivity and mass transfer for water/ethanol separation.

Reboul, Julien; Furukawa, Shuhei; Horike, Nao; Tsotsalas, Manuel; Hirai, Kenji; Uehara, Hiromitsu; Kondo, Mio; Louvain, Nicolas; Sakata, Osami; Kitagawa, Susumu

2012-08-01

107

Anion-driven conformational polymorphism in homochiral helical coordination polymers.  

PubMed

Three homochiral 3D frameworks are assembled based on periodically ordered arrays of helices built from axial chiral 3,3'-bipyridine-5,5',6,6'-tetramethyl-2,2'-dimethoxy-1,1'-biphenyl ligands and linearly coordinated Ag(I) ions. The aggregation behavior of silver salts and the ditopic ligand in solutions was investigated by a variety of techniques, including (1)H NMR, UV-vis, CD, GPC and MALDI-TOF. The cationic polymer skeleton exhibits an unprecedented conformational polymorphism in the solid-state, folding into two-, three- and four-fold helices with NO(3)(-), PF(6)(-) and ClO(4)(-) as the counteranion, respectively. The two-fold helices cross-link via argentophilic Ag-Ag interactions to form sextuple helices, which lead to a three-dimensional (3D) chiral framework. The three-fold or four-fold helices, on the other hand, self-associates in pairs to form three-dimensional tubular architectures. This anion-dependent self-assembly behavior can be rationalized by considering the sizes, geometries and binding abilities of the counteranions and subsequent chain conformation to minimize steric repulsions and maximize secondary interactions. PMID:19722622

Yuan, Guozan; Zhu, Chengfeng; Liu, Yan; Xuan, Weimin; Cui, Yong

2009-08-01

108

Mixed ligand coordination polymers with flexible bis-imidazole linker and angular sulfonyldibenzoate: Crystal structure, photoluminescence and photocatalytic activity  

NASA Astrophysics Data System (ADS)

Four ternary coordination polymers (CPs) namely, {[Ni(SDB)(BITMB)(H2O)]·H2O}n (CP1), {[Cd(SDB)(BITMB) (H2O)]·(THF)(H2O)}n (CP2), {[Zn2(SDB)2(BITMB)]·(THF)2}n (CP3) and {[Co2(SDB)2(BITMB)]·(Dioxane)3}n (CP4) composed of angular dicarboxylate SDB (4,4'-sulfonyldibenzoate) and N-donor BITMB (1,3-bis(imidazol-1-ylmethyl)-2,4,6-trimethyl benzene) have been synthesized by solvothermal reactions and characterized by single crystal X-ray diffraction and other physico-chemical techniques. CP1 possesses one-dimensional ribbon type metal-organic motifs glued together by H-bonds and ?⋯? interactions, whereas CP2-CP4, exhibit non-interpenetrated sql networks supported by weak supramolecular interactions. Structural diversity of these CPs can be attributed to the coordination geometry adopted by the metal nodes, versatile coordination modes of SDB and conformational flexibility of BITMB. Solid state luminescence properties of CP1-CP4 were explored. Photocatalytic performance of all CPs for the decomposition of metanil yellow by dilute hydrogen peroxide in the presence of visible light was also investigated. 25-83% dye removal from aqueous solutions in the presence of CP1-CP4 was observed.

Bisht, Kamal Kumar; Rachuri, Yadagiri; Parmar, Bhavesh; Suresh, Eringathodi

2014-05-01

109

Carbon dioxide (CO2) absorption behavior of mixed matrix polymer composites containing a flexible coordination polymer.  

PubMed

Mixed matrix membranes (MMMs) comprised of metal organic frameworks (MOFs) dispersed in organic polymers are popular materials under study for potential applications in gas separations. However, research on MMMs containing structurally dynamic sorbents known as flexible MOFs has only very recently appeared in the literature. The thermodynamic requirements of the structure transition between the low porosity and high porosity phases of flexible MOFs may provide a mechanism for high adsorption selectivity in these materials. A fundamental question in MMMs containing flexible MOFs is how the constraint of the polymer matrix on the intrinsic expansion of the flexible MOF particles that occurs during gas adsorption might affect the thermodynamics of this structural phase transition and influence the gas adsorption properties of the embedded MOF. To investigate the fundamental nature of this flexible MOF-polymer interface, thin films of ~20 um thickness were prepared using the flexible linear chain coordination polymer catena-bis(dibenzoylmethanato)-(4,4'bipyridyl)nickel(II) "Ni(Bpy)(DBM)(2)" embedded as 35 wt% dispersions in Matrimid®, polystyrene, and polysulfone. The adsorption of CO(2) in the polymers and embedded particles was studied using in situ ATR-FTIR spectroscopy and variable temperature volumetric CO(2) adsorption/desorption isotherms. Interestingly, no effect of the polymer matrix on the gas adsorption behavior of the embedded Ni(Bpy)(DBM)(2) particles was observed. The composite samples all showed the same threshold pressures for CO(2) absorption and desorption hysteresis associated with the structural phase change in the polymer embedded Ni(Bpy)(DBM)(2) particles as was observed in the pristine polycrystalline sample. The current results contrast those recently reported for a MMM containing the flexible MOF "NH(2)-MIL-53" where a significant increase in the threshold pressure for CO(2) adsorption associated with the structural phase change of the MOF was observed in the MMM as compared to the isolated MOF. The conflicting behaviors in these two systems are rationalized from the large differences in unit cell expansions between the two MOFs during the CO(2) adsorption process. PMID:23168045

Culp, Jeffrey T; Sui, Lang; Goodman, Angela; Luebke, David

2013-03-01

110

pH- and mol-ratio dependent formation of zinc(II) coordination polymers with iminodiacetic acid: Synthesis, spectroscopic, crystal structure and thermal studies  

SciTech Connect

Three novel zinc coordination polymers (NH{sub 4}){sub n}[Zn(Hida)Cl{sub 2}]{sub n} (1), [Zn(ida)(H{sub 2}O){sub 2}]{sub n} (2), [Zn(Hida){sub 2}]{sub n}.4nH{sub 2}O (3) (H{sub 2}ida=iminodiacetic acid) and a monomeric complex [Zn(ida)(phen)(H{sub 2}O)].2H{sub 2}O (4) (phen=1,10-phenanthroline) have been synthesized and characterized by X-ray diffraction methods. 1 and 2 form one-dimensional (1-D) chain structures, whereas 3 exhibits a three-dimensional (3-D) diamondoid framework with an open channel. The mononuclear complex 4 is extended into a 3-D supramolecular architecture through hydrogen bonds and pi-pi stacking. Interestingly, cyclic nonplanar tetrameric water clusters are observed that encapsulated in the 3-D lattice of 4. Based on {sup 1}H and {sup 13}C NMR observations, there is obvious coordination of complex 2 in solution, while 1 and 3 decompose into free iminodiacetate ligand. Monomer [Zn(ida)(H{sub 2}O){sub 3}] (5) is considered as a possible discrete species from 2. These coordination polymers can serve as good molecular precursors for zinc oxide. - Text3: Reaction of zinc salt with iminodiacetic acid afforded three new coordination polymers 1-3 and a monomer 4, which is dependent on pH value and molar ratio of the reactants.

Ni Lubin; Zhang Ronghua; Liu Qiongxin; Xia Wensheng [State Key Laboratory of Physical Chemistry of Solid Surfaces, National Engineering Laboratory for Green Chemical Productions of Alcohols-Ethers-Esters, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Wang Hongxin [Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Department of Applied Science, University of California at Davis, Davis, CA 95616 (United States); Zhou Zhaohui, E-mail: zhzhou@xmu.edu.c [State Key Laboratory of Physical Chemistry of Solid Surfaces, National Engineering Laboratory for Green Chemical Productions of Alcohols-Ethers-Esters, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Department of Applied Science, University of California at Davis, Davis, CA 95616 (United States)

2009-10-15

111

Quasi-one-dimensional disordered bipolaronic superconductor  

SciTech Connect

We investigate superconductivity in a quasi-one-dimensional bipolaron system with random potentials, treating the interchain Josephson couplings in the mean-field approximation. The model is transformed into the S = (1/2 XXZ-spin chain with random fields along the z axis and the ordering field along the x axis. Using the quantum transfer-matrix method by the Suzuki-Trotter formula, we calculate the order parameter and the rigidity as functions of the temperature, the mean strength of the random fields, and the ordering field. We obtain the two-parameter scaling laws for these quantities. We also discuss these scaling relations by using the cumulant expansion in the phase Hamiltonian. This analytical method is extended to the more general models of one-dimensional interacting electrons, and the generalized susceptibilities for various long-range orderings are discussed in the light of the scaling laws.

Nagaosa, N.

1989-02-01

112

One-dimensional nano-interconnection formation.  

PubMed

Interconnection of one-dimensional nanomaterials such as nanowires and carbon nanotubes with other parts or components is crucial for nanodevices to realize electrical contacts and mechanical fixings. Interconnection has been being gradually paid great attention since it is as significant as nanomaterials properties, and determines nanodevices performance in some cases. This paper provides an overview of recent progress on techniques that are commonly used for one-dimensional interconnection formation. In this review, these techniques could be categorized into two different types: two-step and one-step methods according to their established process. The two-step method is constituted by assembly and pinning processes, while the one-step method is a direct formation process of nano-interconnections. In both methods, the electrodeposition approach is illustrated in detail, and its potential mechanism is emphasized. PMID:23606447

Ji, Jianlong; Zhou, Zhaoying; Yang, Xing; Zhang, Wendong; Sang, Shengbo; Li, Pengwei

2013-09-23

113

New Ag(I)-containing coordination polymers generated from multidentate Schiff-base ligands.  

PubMed

The coordination chemistry of the multidentate Schiff-base ligands 2,5-bis(3-methylpyrazinyl)-3,4-diaza-2,4-hexadiene (L5) and 2,5-bis(pyrazinyl)-3,4-diaza-2,4-hexadiene (L6) with inorganic Ag(I) salts has been investigated. Six new Ag(I)-coordination polymers were prepared by solution reactions and fully characterized by infrared spectroscopy, elemental analysis, thermogravimetric analysis, and single-crystal X-ray diffraction. [Ag(L5)]ClO(4).0.5CH(3)OH (1, orthorhombic, Fdd2; a = 20.0896(11) A, b = 48.224(3) A, c = 7.8432(4) A, Z = 16), [Ag(L5)]PF(6).0.5CH(3)OH (2, orthorhombic, Fdd2; a = 20.7255(11) A, b = 46.166(2) A, c = 8.4332(4) A, Z = 16), [Ag(L5)]SbF(6).0.5CH(3)OH (3, orthorhombic, Fdd2; a = 21.5481(11) A, b = 45.196(2) A, c = 8.7331(4) A, Z = 16), and [Ag(L5)](BF(4)).0.5CH(3)OH (4, orthorhombic, Fdd2; a = 19.8897(11) A, b = 48.358(3) A, c = 7.7491(5) A, Z = 16) were obtained by combination of L5 with AgClO(4).xH(2)O, AgPF(6), AgSbF(6), and AgBF(4), respectively, in a methylene chloride/methanol mixed solvent system. Compounds 1-4 are isostructural and feature noninterpenetrating three-dimensional zeolite-like networks. [Ag(4)(L6)(4)](PF(6))(4).CHCl(3) (5, tetragonal, Pc2; a = 16.1067(3) A, b = 16.1067(3) A, c = 14.4935(5) A, Z = 2) was generated from the reaction of L6 with AgPF(6) in a chloroform/ethanol mixed solvent system. It forms with a unique one-dimensional nanometer-tube that can be considered a new polymeric motif based on the [AgN5] coordination sphere. The tubes are square with crystallographic dimensions of 10.3 x 10.0 A. The tubes are further linked together through weak interpolymer C-H...F hydrogen bonding interactions into a novel H-bonded three-dimensional network containing square tubes, in which uncoordinated PF(6)(-) counterions and chloroform guest molecules are located. Compound 6 ([Ag(mu-C(6)H(6)N(2)O)](SO(3)CF(3)), monoclinic, P2(1)/c; a = 12.3435(6) A, b = 20.3548(10) A, c = 9.0861(5) A, Z = 8) was obtained by combination of AgSO(3)CF(3) and L6 in a methylene chloride/benzene mixed solvent system. In 6, 2-acetylpyrazine, which was generated from the hydrolysis reaction of L6 in the presence of CF(3)SO(3)(-) and a small quantity of water in solvent, chelates the Ag(I) centers through the carbonyl O-donor, and the vicinal pyrazine N-donor, furthermore, uses the para-N atoms to link other Ag(I) centers into one-dimensional zigzag chains. The triflate anions link the chains into a three-dimensional network by somewhat long Ag.O contacts. PMID:15332812

Dong, Yu-Bin; Zhao, Xia; Huang, Ru-Qi; Smith, Mark D; zur Loye, Hans-Conrad

2004-09-01

114

?-Continuity Properties of One-Dimensional Quasicrystals  

Microsoft Academic Search

:  \\u000a We apply the Jitomirskaya-Last extension of the Gilbert-Pearson theory to discrete one-dimensional Schrödinger operators with\\u000a potentials arising from generalized Fibonacci sequences. We prove for certain rotation numbers that for every value of the\\u000a coupling constant, there exists an ? > 0 such that the corresponding operator has purely ?-continuous spectrum. This result\\u000a follows from uniform upper and lower bounds

David Damanik

1998-01-01

115

Renormalization of one-dimensional avalanche models  

NASA Astrophysics Data System (ADS)

We investigate a renormalization group (RG) scheme for avalanche automata introduced recently by Pietronero et al. to explain universality in self-organized criticality models. Using a modified approach, we construct exact RG equations for a one-dimensional model whose detailed dynamics is exactly solvable. We then investigate in detail the effect of approximations inherent in a practical implementation of the RG transformation where exact dynamical information is unavailable.

Hasty, Jeff; Wiesenfeld, Kurt

1997-03-01

116

Coordination Polymer: Synthesis, Spectral Characterization and Thermal Behaviour of Starch-Urea Based Biodegradable Polymer and Its Polymer Metal Complexes  

PubMed Central

A starch-urea-based biodegradable coordination polymer modified by transition metal Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) was prepared by polycondensation of starch and urea. All the synthesized polymeric compounds were characterized by Fourier transform-infrared spectroscopy (FT-IR), 1H-NMR spectroscopy, 13C-NMR spectroscopy, UV-visible spectra, magnetic moment measurements, differential scanning calorimeter (DSC), and thermogravimetric analysis (TGA). The results of electronic spectra and magnetic moment measurements indicate that Mn(II), Co(II), and Ni(II) complexes show octahedral geometry, while Cu(II) and Zn(II) complexes show square planar and tetrahedral geometry, respectively. The thermogravimetric analysis revealed that all the polymeric metal complexes are more thermally stable than the parental ligand. In addition, biodegradable studies of all the polymeric compounds were also carried out through ASTM standards of biodegradable polymers by CO2 evolution method.

Malik, Ashraf; Parveen, Shadma; Ahamad, Tansir; Alshehri, Saad M.; Singh, Prabal Kumar; Nishat, Nahid

2010-01-01

117

Designing a New Class of Electrocatalysts for Polymer Electrolyte Membrane Fuel Cells: Probing Size, Composition, and Structure Dependent Electrocatalytic Performance in High-Quality, One-Dimensional Noble Metal Nanostructures  

NASA Astrophysics Data System (ADS)

A key challenge in the practical commercialization of PEMFCs is the extremely high cost and relatively poor durability of carbon supported Pt nanoparticle (Pt NP/C) electrocatalysts utilized in both the anode and cathode half-cells. Herein, we synthesize and characterize a new class of high-quality one-dimensional noble metal nanostructures as a potentially new and promising structural paradigm for the next generation of electrocatalyst materials. Specifically, we investigate the nature of the complex interplay amongst size, chemical composition, and electrocatalytic performance in high-quality elemental and bimetallic 1D noble metal nanowire systems with an emphasis on achieving efficient and sustainable methods for catalyst preparation. In terms of nanowire dimensions and composition, an interesting and measureable size-dependent enhancement in performance emerges in the case of elemental Pt, Pd, and Pd1-xAux nanowires possessing diameters ranging from the submicron (d = ˜200 nm) to the ultrathin regime (d = ˜1 nm). In a similar context, we have considered the role of chemical composition in 1D electrocatalysts and noted significant composition-dependent enhancements in activity and durability in high-quality, bimetallic Pd1-xAux and Pd1-xPtx NWs. A key finding that is apparent from these experimental results is that widely seen behavioral trends in the composition- and size-dependent performance for 0D nanoparticle-based catalysts do not hold in the case of 1D architectures, because of the patently unique structural and electronic effects, associated with their anisotropic structures. As a culmination of our efforts to take advantage of these intrinsic structure-activity correlations, our group has developed a morphology-, size-, and composition-optimized Pd9Au NW possessing a Pt monolayer shell (PtML˜Pd9Au NWs) electrocatalyst with an ultrathin 2 nm diameter, which yielded outstanding Pt mass and platinum group metal activities of 2.56 A/mgPt and 0.64 A/mgPGM, respectively, thereby surpassing the activity of conventional state-of-the-art Pt NP/C by more than ten-fold.

Koenigsmann, Christopher

118

A statistical formulation of one-dimensional electron fluid turbulence  

NASA Technical Reports Server (NTRS)

A one-dimensional electron fluid model is investigated using the mathematical methods of modern fluid turbulence theory. Non-dissipative equilibrium canonical distributions are determined in a phase space whose co-ordinates are the real and imaginary parts of the Fourier coefficients for the field variables. Spectral densities are calculated, yielding a wavenumber electric field energy spectrum proportional to k to the negative second power for large wavenumbers. The equations of motion are numerically integrated and the resulting spectra are found to compare well with the theoretical predictions.

Fyfe, D.; Montgomery, D.

1977-01-01

119

Observation of a large magnetocaloric effect in a 2D Gd(III)-based coordination polymer.  

PubMed

A new 2D Gd(III)-based coordination polymer has close to the highest cryogenic magnetocaloric effect of any MOF reported so far. The experimental results reveal its structural features and magnetic properties. PMID:23942852

Biswas, Soumava; Adhikary, Amit; Goswami, Soumyabrata; Konar, Sanjit

2013-10-01

120

A nanosized Gd(6)Ni(3) cluster-based heterometallic coordination polymer.  

PubMed

A nanosized Gd(6)Ni(3) cluster-based two-dimensional 3d-4f heterometallic coordination polymer has been synthesized under hydrothermal conditions using a mixture of H(4)PMIDA (H(4)PMIDA = N-(phosphonomethyl) iminodiacetic acid), Gd(ClO(4))(3) and Ni(CH(3)COO)(2).4H(2)O. An electrical property investigation reveals that the coordination polymer exhibits a proton conductivity. PMID:20419190

Zhuang, Gui-Lin; Jin, Yi-Chang; Zhao, Hai-Xia; Kong, Xiang-Jian; Long, La-Sheng; Huang, Rong-Bin; Zheng, Lan-Sun

2010-04-23

121

Phonon spectra in one-dimensional quasicrystals  

SciTech Connect

The propagation of phonons in one-dimensional quasicrystals is investigated. The authors use the projection method which has been recently proposed to generate almost periodic tilings of the line. They define a natural Laplace operator on these structures which models phonon (and also tight-binding electron) propagation. The self-similarity properties of the spectrum are discussed, as well as some characteristic features of the eigenstates, which are neither extended nor localized. The long-wavelength limit is examined in more detail; it is argued that one is the lower critical dimension for this type of models.

Luck, J.M.; Petritis, D.

1986-02-01

122

Quasi-one-dimensional thermal breakage  

NASA Astrophysics Data System (ADS)

Breakage is generally understood in mechanical terms, yet nanostructures can rupture not only under external loads but also via thermal activation. Here we treat in a general framework the statistical mechanics of thermally induced breakage at the nanoscale for one-dimensional systems. We test it on a simple approximation and find that the probability of breakage controls distinct regimes, characterized by sharp crossovers and narrow peaks in the thermal fluctuations and specific heat. Our work provides predictions on clustering of new phases, of relevance in nanofabrication.

Nisoli, Cristiano; Abraham, Douglas; Lookman, Turab; Saxena, Avadh

2013-10-01

123

A one-dimensional tunable magnetic metamaterial.  

PubMed

We present experimental data on a one-dimensional super-conducting metamaterial that is tunable over a broad frequency band. The basic building block of this magnetic thin-film medium is a single-junction (rf-) superconducting quantum interference device (SQUID). Due to the nonlinear inductance of such an element, its resonance frequency is tunable in situ by applying a dc magnetic field. We demonstrate that this results in tunable effective parameters of our metamaterial consisting of 54 rf-SQUIDs. In order to obtain the effective magnetic permeability ?r,eff from the measured data, we employ a technique that uses only the complex transmission coefficient S??. PMID:24104143

Butz, S; Jung, P; Filippenko, L V; Koshelets, V P; Ustinov, A V

2013-09-23

124

Quasi-one-dimensional thermal breakage.  

PubMed

Breakage is generally understood in mechanical terms, yet nanostructures can rupture not only under external loads but also via thermal activation. Here we treat in a general framework the statistical mechanics of thermally induced breakage at the nanoscale for one-dimensional systems. We test it on a simple approximation and find that the probability of breakage controls distinct regimes, characterized by sharp crossovers and narrow peaks in the thermal fluctuations and specific heat. Our work provides predictions on clustering of new phases, of relevance in nanofabrication. PMID:24229191

Nisoli, Cristiano; Abraham, Douglas; Lookman, Turab; Saxena, Avadh

2013-10-01

125

1D Cu(II) coordination polymer derived from 2-(2-(2,4-dioxopentan-3-ylidene)hydrazinyl)benzenesulfonate chelator and pyrazine spacer  

NASA Astrophysics Data System (ADS)

Reaction of 2-(2-(2,4-dioxopentan-3-ylidene)hydrazinyl)benzenesulfonic acid (H2L) with copper(II) nitrate hydrate in the presence of pyrazine (pz) in methanol affords the coordination polymer [Cu2(?-L)2(H2O)2(?-pz)]n (1), where the bidentate pz molecule links two Cu(II) centres of two different dimeric units, giving rise to a one-dimensional chain. The dimeric unit [Cu2(?-L)2(H2O)2] consists of two distorted octahedral Cu(II) centres connected via oxygen atoms of the sulfo group of the bridging L2- ligand. The extensive hydrogen bonding between the coordinated water and pz molecules leads to the formation of a supramolecular 3D associate. Compound 1 has been characterized by elemental analysis, ESI-MS, IR spectroscopy and single-crystal X-ray diffraction analysis.

Mahmudov, Kamran T.; Haukka, Matti; Sutradhar, Manas; Mizar, Archana; Kopylovich, Maximilian N.; Pombeiro, Armando J. L.

2013-02-01

126

One dimensional spindle titanium oxide nanocrystals.  

PubMed

Anatase TiO2 nanocrystals of 10 nm were formed in aqueous solutions at 90 degrees C for 1 day. The solutions contained ammonium hexafluorotitanate (5 mM) and boric acid (15 mM). The nanocrystals connected each other to form particles of about 100-500 nm. X-ray diffraction, Raman and FT-IR analysis revealed characteristics of the nanocrystals. They had BET surface area of 68 m2/g. Furthermore, morphology was controlled to one dimensional spindle shape by change of supersaturation degree. The spindle nanocrystals of 30 nm in width and 100 nm in length were formed in low concentration solutions. They contained hexafluorotitanate of 0.5 mM and boric acid of 0.15 mM. The spindle nanocrystals had higher crystallinity compared to the above nanocrystals. BET surface area reached 88 m2/g. One dimensional structure was realized by anisotropic crystal growth along c-axis. Low supersaturation degree decreased growth speed and brought out anisotropic crystal growth. PMID:24734718

Masuda, Yoshitake; Kato, Kazumi

2014-04-01

127

Crossover from reptation to Rouse dynamics in a one-dimensional model  

NASA Astrophysics Data System (ADS)

A simple one-dimensional model is constructed for polymer motion. It exhibits the crossover from reptation to Rouse dynamics through gradually allowing hernia creation and annihilation. The model is treated by the density matrix technique which permits an accurate finite-size-scaling analysis of the behavior of long polymers.

Drzewi?ski, Andrzej; van Leeuwen, J. M. J.

2006-06-01

128

A series of Ti(IV)/Ti(III) coordination polymers: structures and surface photoelectric properties.  

PubMed

Three titanium coordination polymers, {[Ti(SO(4))(2)(H(2)O)]·0.5bipy·2H(2)O}(n)1, {[Ti1(SO(4))(2)(H(2)O)]·[Ti2(SO(4))(2)(H(2)O)]·bipy·5H(2)O}(n)2 and [Ti(tea)](n)3 (bipy=4,4'-bipyridine, H(3)tea=triethanolamine) were synthesized and characterized by IR, UV-Vis absorption spectra, TG analysis, X-ray single crystal diffraction and surface photovoltage spectroscopy (SPS). The surface photoelectric properties of titanium coordination polymers were discussed emphatically by the SPS. The results of single crystal diffraction indicate that polymers 1 and 2 possess 1D infinite structure bridged by SO(4)(2-) groups and coordinated water molecules and further connected into supramolecular structures by hydrogen bonds. Polymer 3 possesses 2D infinite structure bridged by weak sub-coordinated Ti-O bonds. The results of SPS show that there are obvious photovoltage responses in the range of 300-500 nm, which indicates that they possess photoelectric conversion ability. The SPS of three titanium polymers were analyzed comparatively. It is found that the valence of central metal ions, coordination micro-environment and kinds of coordination atoms influence the results of the SPS. The SPS is associated with UV-Vis absorption spectra. PMID:22051416

Li, Lei; Zhang, Li; Liu, Dong-Wei; Jin, Jing; Chi, Yu-Xian; Niu, Shu-Yun

2012-02-01

129

Metal ions and solvents ratio co-regulate four new magnetic coordination polymers based upon an unsymmetric tricarboxylate acid ligand.  

PubMed

Four new coordination polymers (CPs), [Co3(L)2(bib)3(EtOH)2]·2H2O (), [Mn3(L)2(bib)2(H2O)4]·4H2O (), [Ni(HL)(bib)(H2O)3] () and [Ni3(bib)4(H2O)10]·2(L)·12(H2O) (), were synthesized under solvothermal conditions with an unsymmetrical tricarboxylic acid ligand [biphenyl-3,3',5-tricarboxylic acid (H3L)] in the presence of the 1,4-bis(1H-imidazol-4-yl)benzene (bib) ligand. In compound , tricarboxylate acid ligands (H3L) link Co centers to generate two-dimensional (2D) layers which are further connected by bib ligands to exhibit a three-dimensional (3D) framework with a (4,4,5)-connected (4(2)·6(3)·8)2(4(2)·6(7)·8)2(6(4)·8·10) topology. The three-dimensional (3D) framework of is defined as a (3,3,4)-connected topology with the point symbol of (6·8(2))2(6(2)·8)2(8·10(4)·12). Compound contains a one-dimensional (1D) left-hand helix chain along the a direction and further extends into a 2D supramolecular network and a 3D supramolecular framework via hydrogen bonds. Compound displays a one-dimensional (1D) molecular ladder, which is further combined with each other through ?? stacking to extend into 2D supramolecular sheets. The supramolecular networks of and resulted from the different solvent ratios [V(H2O)-V(EtOH)] in the reaction. All the CPs are characterized by single-crystal X-ray diffraction analyses, powder X-ray diffraction (PXRD), elemental analyses, IR spectroscopy, and TGA analyses. Moreover, the weak ferromagnetic properties of and and antiferromagnetic properties of and have also been investigated. PMID:24905184

Li, Yuan-Pu; Chai, Ying; Yang, Guo-Ping; Miao, Hui-Hui; Cui, Lin; Wang, Yao-Yu; Shi, Qi-Zhen

2014-06-24

130

One-dimensional Vlasov--Maxwell equilibria  

SciTech Connect

The purpose of this paper is to show that the Vlasov equilibrium of a plasma of charged particles in an electromagnetic field is closely related to a fluid equilibrium, where only a few moments of the velocity distribution of the plasma are considered. In this fluid equilibrium the electric field should be calculated from Ohm's law, rather than the Poisson equation. In practice, only one-dimensional equilibria are treated, because the symmetry makes this case tractable. The emphasis here is on gaining a better understanding of the subject, but an alternate way of doing the calculations is suggested. It is shown that particle distributions can be found that are consistent with any reasonable electromagnetic field profile.

Greene, J.M. (General Atomics, San Diego, California 92186-9784 (United States))

1993-06-01

131

Three one-dimensional structural heating programs  

NASA Technical Reports Server (NTRS)

Two computer programs for calculating profiles in a ten-element structure consisting of up to ten materials are presented, along with a third program for calculating the mean temperature for a payload container placed in an orbiting vehicle cargo bay. The three programs are related by the sharing of a common analytical technique; the energy balance is based upon one-dimensional heat transfer. The first program, NQLDW112, assumes a non-ablating surface. NQLDW117 is very similar but allows the outermost element to ablate. NQLDW040 calculates an average temperature profile through an idealized model of the real payload cannister and contents in the cargo bay of an orbiting vehicle.

Wing, L. D.

1978-01-01

132

Collision of one-dimensional fermion clusters  

NASA Astrophysics Data System (ADS)

We study cluster-cluster collisions in one-dimensional Fermi systems with particular emphasis on the nontrivial quantum effects of the collision dynamics. We adopt the Fermi-Hubbard model and the time-dependent density-matrix renormalization-group method to simulate collision dynamics between two fermion clusters of different spin states with contact interaction. It is elucidated that the quantum effects become extremely strong with the interaction strength, leading to the transmittance being much more enhanced than expected from the semiclassical approximation. We propose a concise model as an application of the Bethe ansatz, which unveils the origin of the quantum effects and also explains the overall properties of the simulation results clearly. This model provides an intuitive perspective of the collision dynamics with contact interaction. Some potential applications, such as repeated collisions, are addressed.

Ozaki, Jun'ichi; Tezuka, Masaki; Kawakami, Norio

2012-09-01

133

One-Dimensional Photonic Crystal Superprisms  

NASA Technical Reports Server (NTRS)

Theoretical calculations indicate that it should be possible for one-dimensional (1D) photonic crystals (see figure) to exhibit giant dispersions known as the superprism effect. Previously, three-dimensional (3D) photonic crystal superprisms have demonstrated strong wavelength dispersion - about 500 times that of conventional prisms and diffraction gratings. Unlike diffraction gratings, superprisms do not exhibit zero-order transmission or higher-order diffraction, thereby eliminating cross-talk problems. However, the fabrication of these 3D photonic crystals requires complex electron-beam substrate patterning and multilayer thin-film sputtering processes. The proposed 1D superprism is much simpler in structural complexity and, therefore, easier to design and fabricate. Like their 3D counterparts, the 1D superprisms can exhibit giant dispersions over small spectral bands that can be tailored by judicious structure design and tuned by varying incident beam direction. Potential applications include miniature gas-sensing devices.

Ting, David

2005-01-01

134

One-dimensional spin-orbit interferometer  

NASA Astrophysics Data System (ADS)

We demonstrate that the combination of an external magnetic field and the intrinsic spin-orbit interaction results in nonadiabatic precession of the electron spin after transmission through a quantum point contact (QPC). We suggest that this precession may be observed in a device consisting of two QPCs situated in series. The pattern of resonant peaks in the transmission is strongly influenced by the non-Abelian phase resulting from this precession. Moreover, an unusual type of resonance which is associated with suppressed, rather than enhanced, transmission (i.e., antiresonance) emerges in the strongly nonadiabatic regime. The shift in the resonant transmission peaks is dependent on the spin-orbit interaction and therefore offers a way to directly measure these interactions in a ballistic one-dimensional system.

Li, Tommy; Sushkov, Oleg P.

2013-04-01

135

Tellurium-containing polymer micelles: competitive-ligand-regulated coordination responsive systems.  

PubMed

Nanomaterials capable of achieving tunable cargo release kinetics are of significance in a fundamental sense and various biological or medical applications. We report a competitive coordination system based on a novel tellurium-containing polymer and its ligand-regulated release manners. Tellurium was introduced to water-soluble polymers for the first time as drug delivery vehicles. The coordination chemistry between platinum and tellurium was designed to enable the load of platinum-based drugs. Through the competitive coordination of biomolecules, the drugs could be released in a controlled manner. Furthermore, the release kinetics could be modulated by the competitive ligands involved due to their different coordination ability. This tellurium-containing polymer may enrich the family of delivery systems and provide a new platform for future biomedical nanotechnologies. PMID:24605909

Cao, Wei; Gu, Yuwei; Meineck, Myriam; Li, Tianyu; Xu, Huaping

2014-04-01

136

Wavelength dependence of optical nonlinearity of terpyridine-based Zn(II)-coordinated rigid linear polymers  

NASA Astrophysics Data System (ADS)

We present the wavelength dependent optical nonlinearities of two terpyridine-based Zn(II)-coordinated rigid linear polymers. It is found that the polymers exhibit large saturable absorption behavior under resonant excitation, while strong and tunable 2-photon absorption behaviors are observed in the biological window of 700-900 nm. Interestingly, Z-scan results reveal that, the polymers also exhibit large positive nonlinear refraction at 1300 nm in the solutions even with a low concentration, accompanied by small 3-photon absorption. Our results suggest that the polymers will be promising in various photonic applications, such as mode locking, 2-photon biological imaging, and all-optical switching.

He, Tingchao; Rajwar, Deepa; Ma, Lin; Wang, Yue; Bang Lim, Zheng; Grimsdale, Andrew C.; Sun, Handong

2012-11-01

137

Highly luminescent and triboluminescent coordination polymers assembled from lanthanide ?-diketonates and aromatic bidentate O-donor ligands.  

PubMed

The reaction of hydrated lanthanide hexafluoroacetylacetonates, [Ln(hfa)(3)(H(2)O)(2)], with 1,4-disubstituted benzenes afforded a new series of one-dimensional coordination polymers [Ln(hfa)(3)(Q)](?), where Ln = Eu, Gd, Tb, and Lu and Q = 1,4-diacetylbenzene (acbz), 1,4-diacetoxybenzene (acetbz), or 1,4-dimethyltherephtalate (dmtph). X-ray single crystal analyses reveal [Ln(hfa)(3)(acbz)](?) (Ln = Eu, Gd, Tb) consisting of zigzag polymeric chains with Ln-Ln-Ln angles equal to 128°, while the arrays are more linear in [Eu(hfa)(3)(acetbz)](?) and [Eu(hfa)(3)(dmtph)](?), with Ln-Ln-Ln angles of 165° and 180°, respectively. In all structures, Ln(III) ions are 8-coordinate and lie in distorted square-antiprismatic environments. The coordination polymers are thermally stable up to 180-210 °C under a nitrogen atmosphere. Their volatility has been tested in vacuum sublimation experiments at 200-250 °C and 10(-2) Torr: the metal-organic frameworks with acetbz and dmtph can be quantitatively sublimed, while [Ln(hfa)(3)(acbz)](?) undergoes thermal decomposition. The triplet state energies of the ancillary ligands, 21,600 (acetbz), 22,840 (acbz), and 24,500 (dmtph) cm(-1), lie in an ideal range for sensitizing the luminescence of Eu(III) and/or Tb(III). As a result, all of the [Ln(hfa)(3)(Q)](?) polymers display bright red or green luminescence due to the characteristic (5)D(0) ? (7)F(J) (J = 0-4) or (5)D(4) ? (7)F(J) (J = 6-0) transitions, respectively. Absolute quantum yields reach 51(Eu) and 56(Tb) % for the frameworks built from dmtph. Thin films of [Eu(hfa)(3)(Q)](?) with 100-170 nm thickness can be obtained by thermal evaporation (P < 3 × 10(-5) Torr, 200-250 °C). They are stable over a long period of time, and their photophysical parameters are similar to those of the bulk samples so that their use as active materials in luminescent devices can be envisaged. Mixtures of [Ln(hfa)(3)(dmpth)](?) with Ln = Eu and Tb yield color-tunable microcrystalline materials from red to green. Finally, the crystalline samples exhibit strong triboluminescence, which could be useful in the design of pressure and/or damage detection probes. PMID:20849088

Eliseeva, Svetlana V; Pleshkov, Dmitry N; Lyssenko, Konstantin A; Lepnev, Leonid S; Bünzli, Jean-Claude G; Kuzmina, Natalia P

2010-10-18

138

One-dimensional magnetic inorganic-organic hybrid nanomaterials.  

PubMed

One-dimensional (1D) magnetic inorganic-organic hybrid nanomaterials bear both the intrinsic magnetic properties of the inorganic components and the functionality and responsiveness of their organic part. In this tutorial review, we first emphasize various synthetic strategies for this type of materials: (i) template-directed synthesis employs different preformed templates such as channels in solids, mesostructures self-assembled from block copolymers, cylindrical polymer brushes, 1D biological templates and other existing 1D templates; (ii) electrospinning, which provides a simple and efficient technique that can lead to a potential large-scale production; (iii) 1D conjugation of building blocks which combines the physical attraction of magnetic nanoparticles in a magnetic field with chemical crosslinking and stabilization. The properties, functions and the future trends of these materials are also briefly introduced. It is foreseeable that these hybrid materials will play more and more important roles in the ever-advancing miniaturization of functional devices. PMID:21206943

Yuan, Jiayin; Xu, Youyong; Müller, Axel H E

2011-02-01

139

One-dimensional magnetopolymeric nanostructures with tailored sizes.  

PubMed

Ultra-high aspect ratio nanofibers composed of poly(vinyl alcohol) and CoFe(2)O(4) nanoparticles (PVA/CoFe(2)O(4)) and moderate aspect ratio nanofibers composed of poly(vinyl chloride) and Fe(3)O(4) nanoparticles (PVC/Fe(3)O(4)) have been prepared. Magnetopolymeric one-dimensional (1D) nanostructures with any diameter and length can be prepared by template synthesis using anodic aluminum oxide (AAO) followed by the replication methods presented in this work. These replication methods are very effective, and allow the nanomoulding of any polymer-nanoparticle 1D composite. A first magnetic characterization of the nanostructured composites reveals a modest magnetic anisotropy. The development of magnetopolymeric nanofibers with adjusted length and diameter opens new opportunities in a wide range of applications. PMID:21825668

Martín, J; Vázquez, M; Hernández-Vélez, M; Mijangos, C

2008-04-30

140

One-dimensional magnetopolymeric nanostructures with tailored sizes  

NASA Astrophysics Data System (ADS)

Ultra-high aspect ratio nanofibers composed of poly(vinyl alcohol) and CoFe2O4 nanoparticles (PVA/CoFe2O4) and moderate aspect ratio nanofibers composed of poly(vinyl chloride) and Fe3O4 nanoparticles (PVC/Fe3O4) have been prepared. Magnetopolymeric one-dimensional (1D) nanostructures with any diameter and length can be prepared by template synthesis using anodic aluminum oxide (AAO) followed by the replication methods presented in this work. These replication methods are very effective, and allow the nanomoulding of any polymer-nanoparticle 1D composite. A first magnetic characterization of the nanostructured composites reveals a modest magnetic anisotropy. The development of magnetopolymeric nanofibers with adjusted length and diameter opens new opportunities in a wide range of applications.

Martín, J.; Vázquez, M.; Hernández-Vélez, M.; Mijangos, C.

2008-04-01

141

Cd(II) and Co(II) coordination polymers constructed from benzene-1,4-dicarboxylic acid and 2-(pyridin-3-yl)-1H-benzimidazole ligands.  

PubMed

In poly[aqua(?3-benzene-1,4-dicarboxylato-?(5)O(1),O(1'):O(1):O(4),O(4'))[2-(pyridin-3-yl-?N)-1H-benzimidazole]cadmium(II)], [Cd(C8H4O4)(C12H9N3)(H2O)]n, (I), each Cd(II) ion is seven-coordinated by the pyridine N atom from a 2-(pyridin-3-yl)benzimidazole (3-PyBIm) ligand, five O atoms from three benzene-1,4-dicarboxylate (1,4-bdc) ligands and one O atom from a coordinated water molecule. The complex forms an extended two-dimensional carboxylate layer structure, which is further extended into a three-dimensional network by hydrogen-bonding interactions. In catena-poly[[diaquabis[2-(pyridin-3-yl-?N)-1H-benzimidazole]cobalt(II)]-?2-benzene-1,4-dicarboxylato-?(2)O(1):O(4)], [Co(C8H4O4)(C12H9N3)2(H2O)2]n, (II), each Co(II) ion is six-coordinated by two pyridine N atoms from two 3-PyBIm ligands, two O atoms from two 1,4-bdc ligands and two O atoms from two coordinated water molecules. The complex forms a one-dimensional chain-like coordination polymer and is further assembled by hydrogen-bonding interactions to form a three-dimensional network. PMID:24816019

Chen, Xiao-Hua; Huang, Hua; Yang, Ming-Xing; Chen, Li-Juan; Lin, Shen

2014-05-01

142

Coordination polymer chains built from Cu(II) and adipate ions linked by hydrogen bonds to form a three-dimensional framework structure.  

PubMed

In the title compound, catena-poly[bis[(2,2'-bipyridine-?(2)N,N')(1,1,3,3-tetracyano-2-ethoxypropenido-?N)copper(II)]-?4-hexanedioato-?(6)O(1),O(1'):O(1):O(6),O(6'):O(6)], [Cu2(C9H5N4O)2(C6H8O4)(C10H8N2)2]n, the adipate (hexanedioate) dianion lies across a centre of inversion in the space group P\\overline{1}. The Cu(II) centre adopts a distorted form of axially elongated (4+2) coordination, and the Cu(II) and adipate components form a one-dimensional coordination polymer from which the 2,2'-bipyridine and 1,1,3,3-tetracyano-2-ethoxypropenide components are pendent, and where each adipate dianion is bonded to four different Cu(II) centres. The coordination polymer chains are linked into a three-dimensional framework structure by a combination of C-H...N and C-H...O hydrogen bonds, augmented by a ?-? stacking interaction. PMID:24992115

Setifi, Zouaoui; Boutebdja, Mehdi; Setifi, Fatima; Merazig, Hocine; Glidewell, Christopher

2014-07-15

143

Correlation in the one dimensional electron gas  

NASA Astrophysics Data System (ADS)

We explore the role of electron correlation in quasi one dimensional quantum wires. We consider the effects of experimental parameters on the interaction, including screening by gates and other wires as well as the strength of the confinement to one dimension. We present the results of highly accurate quantum Monte Carlo calculations of the energy of the electron gas at various densities and polarizations. This data which is available along with this dissertation allows the construction of exchange-correlation functionals suitable for density functional calculations. We present sample functionals which are valid at any given density. In the case of unscreened interactions with a long range 1/x tail there is a crossover from a liquid to a quasi Wigner crystal state as the density decreases. When this interaction is screened, quasi long range order is prevented from forming, although a significant correlation with 4kF periodicity is still present at low densities. At even lower electron density, exchange is suppressed and the electrons behave like spinless fermions. These results are also supported by calculations of the momentum resolved spin and charge excitation energies. The long wavelength portions of these spectra also are used to calculate the spin susceptibility and charge compressibility of the electron gas. Our calculations are quantitatively exact which allows us to compare with recent experiments [Steinberg et al., Phys. Rev. B 77, 113307 (2006)], by introducing an accurate model for the screening in the experiment and explicitly including the finite length of the sample in our simulations. We find that decreasing the electron density drives the system from a liquid to a state with rather strong 4kF correlations. This crossover takes place around 22 microm-1, near the density where the electron localization occurs in the experiment. The charge and spin velocities determined from the long wavelength excitation spectra are also in good agreement with the experimental findings. We argue that correlation effects play an important role at the onset of the localization transition.

Shulenburger, Luke Nathan

144

The one-dimensional nature of polyynes  

NASA Astrophysics Data System (ADS)

Carbyne is a hypothetical carbon allotrope that consists of sp-hybridized carbon atoms in an infinitely-long, one-dimensional (1-D) linear chain. Polyynes, the oligomeric cousins of carbyne, with a dense delocalized-electron framework, could offer groundbreaking electronic properties. We have studied the linear and third-order nonlinear optical properties of both triisopropylsilyl end-capped (TIPS-PY) and phenyl end-capped (p-PY) polyynes containing pure sp-hybridized carbon backbones. Analysis of the TIPS-polyyne UV-vis absorption spectra shows that the absorption gap, Eg, in these materials scales very precisely as a power-law with increasing oligomer length, n, with Eg~n-0.379+/-0.002. The phenylated polyynes show a similar trend of Eg~n-0.36+/-0.01. Ultrafast molecular second-hyperpolarizabilities, ?, were obtained in solution using 800nm, 100fs pulses in a differential optical Kerr effect (DOKE) setup. Polyyne second-hyperpolarizabilities also scale with a power-law, and, surprisingly, with exponents higher than that of any other reported oligomer system, yielding a behavior of ?~n4.3+/-0.1 and ?~n3.8+/-0.1 for the TIPS-polyynes and phenylated-polyynes, respectively. These findings contrast direct theoretical predictions that increases in gamma with increasing conjugation length for polyynes should be considerably lower than those of polyenes and polyenynes. Furthermore, the combined linear and nonlinear optical results agree with recent theoretical studies on ideal 1-D conjugated systems, suggesting that polyynes display true 1-D behavior.

Slepkov, Aaron D.; Eisler, Sara; Luu, Thanh; Elliot, Erin; Tykwinski, Rik R.; Hegmann, Frank A.

2005-08-01

145

Aggregation behaviour below the gelation threshold for metal-olefin coordination in diene polymers  

Microsoft Academic Search

This study focuses on aggregation below the gelation threshold in ternary solutions containing diene polymers, atactic 1,2-polybutadiene (PBu) or 3,4-polyisoprene (PI), and an inorganic salt, bis(acetonitrile) dichloropalladium(II). Upon mixing, effective coordination crosslinks are formed because the acetonitrile ligands of the palladium salt are displaced by olefinic pendant groups of the polymers. In all cases, the aggregation kinetics correlate with PdCl2

Francis Bossé; Pronab Das; Laurence A. Belfiore

1997-01-01

146

Engineering metal-based luminescence in coordination polymers and metal-organic frameworks.  

PubMed

The rapidly growing number of luminescent coordination polymers (CPs) and metal-organic frameworks (MOFs) illustrates high interest as well as accessibility of such materials. The interplay between inorganic and organic components in these materials offers a large number of viable luminescence processes. The enormous variability of available ligand-metal combinations opens the possibility of creating luminescence "by design", based on a proper understanding of the processes involved. Together with the multifunctionality of MOFs (e.g. porosity) further options like sensing become accessible. This tutorial review covers the main luminescence processes and focuses especially on metal-based luminescence of coordination polymers and MOFs. PMID:24077361

Heine, Johanna; Müller-Buschbaum, Klaus

2013-12-21

147

An exceptional 54-fold interpenetrated coordination polymer with 10(3)-srs network topology.  

PubMed

Entanglement is one of the most important features of coordination polymer frameworks and has attracted considerable attention due to its aesthetic and topological interest. Among entangled systems, interpenetrating frameworks represent an intriguing subset; however, there are few examples of materials containing very high levels of interpenetration. In this work a coordination polymer with 10(3)-srs topology, constructed from a star-like tridentate ligand, tri(4-imidazolylphenyl)amine, and Ag(I) ions, has been hydrothermally synthesized. It contains a record 54 interpenetrating networks. PMID:21728370

Wu, Hua; Yang, Jin; Su, Zhong-Min; Batten, Stuart R; Ma, Jian-Fang

2011-08-01

148

Iron(II) and Copper(I) Coordination Polymers:  Electrochromic Materials with and without Chiroptical Properties  

Microsoft Academic Search

The electrochemical and optical properties of films prepared from two different Fe(II) coordination polymers (TPT(FeIITPT)n(PF6)2n (TPT ) terpyridine-phenyl-terpyridine) and CTPCT(FeIICTPCT)n(PF6)2n (CTPCT ) chiral terpyridine-phenyl-chiral terpyridine)) and a coordination polymer based on Cu(I) metal centers (PDP(CuIPDP)n- (BF4)n )( PDP ) phenanthroline-dodecane-phenanthroline) have been studied. The oxidation of a PDP(CuIPDP)n- (BF4)n film coated on an indium-tin oxide (ITO) electrode by stepping the

Stefan Bernhard; Jonas I. Goldsmith; Kazutake Takada; Hector D. Abruna

2003-01-01

149

3D pillar-layered coordination polymers based on 4d-4f heterometallic assembly  

NASA Astrophysics Data System (ADS)

By control of mixed ligands with particular coordination sites, heterometallic coordination polymers, [Ln 2(H 2O) 2Ag(C 2O 4) 2(ina) 3] n (Ln = Eu ( 1), Dy ( 2), Hina = isonicotinic acid) and {[LnAg(C 2O 4)(na) 2]·2H 2O} n (Ln = La ( 3), Tb ( 4), Hna = nicotinic acid), have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR, thermogravimetric analysis (TGA), and single-crystal X-ray diffraction. These coordination polymers feature 3D pillar-layered coordination frameworks constructed from two-dimensional (2D) lanthanide-carboxylate layers and Ag(ina) or Ag(na) pillars. It is interesting that the in situ decarboxylation of pyridine-2,3-dicarboxylic acid into nicotinic acid was observed. The luminescent properties of 1 and 4 were also studied.

He, Yong-Ke; An, Hai-Yan; Han, Zheng-Bo

2009-01-01

150

Amphiphilic nanocapsules entangled with organometallic coordination polymers for controlled cargo release.  

PubMed

A class of new amphiphilic nanocapsules entangled with organometallic coordination polymers has been developed for the first time. Poly(2-(N,N-dimethyl amino)ethyl methacrylate)-b-polystyrene capped with ?-cyclodextrin (?-CD) (CD-PDMAEMA-b-PS) is first synthesized using sequent RAFT polymerization of styrene and 2-(N,N-dimethyl amino)ethyl methacrylate with xanthate modified ?-CD as chain transfer agent. The end group of ?-CD is allowed to include 4,4'-bipyridine through host-guest inclusion to yield PDMAEMA-b-PS terminated with an inclusion complex of ?-CD and bipyridine (bpy-PDMAEMA-b-PS), which is then used as surfactant to prepare emulsion droplets in toluene/water mixture. Upon addition of Ni(II), bipyridine coordinates with Ni(II) to form coordination polymers in the periphery of emulsion droplets, affording amphiphilic capsules entangled with organometallic coordination polymers, as confirmed by GPC, (1)H NMR, SEM, TEM, DLS, and so on. The organometallic coordination polymer capsules are capable of encapsulating organic cargoes. Interestingly, encapsulated cargoes can be extracted from the capsules without damaging the capsules. Such capsules are potential candidates for encapsulating and controlled release of organic cargoes. PMID:24828951

Liang, Guodong; Ni, Huan; Bao, Suping; Zhu, Fangming; Gao, Haiyang; Wu, Qing; Tang, Ben Zhong

2014-06-01

151

Selective metal substitution for the preparation of heterobimetallic microporous coordination polymers.  

PubMed

The designed synthesis of heterobimetallic microporous coordination polymers (MCPs) is reported by a strategy employing the selective replacement of a single metal in homometallic MCPs with two unique metal coordination environments: octahedral and tetrahedral. This strategy is successful in the preparation of six mixed-metal MCPs, where Co/Zn and Ni/Zn versions of MOF-4, MOF-39, and a Zn-BTEC MCP are reported. PMID:18714988

Caskey, Stephen R; Matzger, Adam J

2008-09-15

152

"Click-and-click"--hybridised 1,2,3-triazoles supported Cu(I) coordination polymers for azide-alkyne cycloaddition.  

PubMed

Two novel pyridyl and thioether hybridised 1,2,3-triazole ligands 1-(2-picolyl)-4-(2-(methylthio)-pyridine)-1H-1,2,3-triazole (L1) and 1-(4-picolyl)-4-(2-(methylthio)-pyridine)-1H-1,2,3-triazole (L2) were prepared from CuAAC click reactions. Reactions of CuI with the ligands L1 and L2 yielded two one-dimensional coordination polymers [Cu6I6(L1)2]n (1) and [Cu2I2(L2)2]n (2). Single-crystal X-ray diffraction reveals that 1 and 2 are polymeric with [Cu6I6] and [Cu2I2] respectively as building blocks. Both ligands (L1 and L2) and complexes (1 and 2) are photoluminescence active. Complexes 1 and 2 are also catalytically active towards azide-alkyne cycloaddition reactions. PMID:23695801

Jiang, Lu; Wang, Zhe; Bai, Shi-Qiang; Hor, T S Andy

2013-07-14

153

Bayesian Estimation of One Dimensional Discrete Markov Random Fields.  

National Technical Information Service (NTIS)

This document presents two deterministic algorithms for the maximum a posteriori estimation of a one dimensional, binary Markov random field from noisy observations. Extensions to other related problems, such as one dimensional signal matching, and estima...

J. L. Marroquin

1984-01-01

154

Supramolecular polymers with tunable topologies via hierarchical coordination-driven self-assembly and hydrogen bonding interfaces  

PubMed Central

A powerful strategy to obtain complex supramolecular materials is the bottom-up construction of noncovalently bound materials by hierarchical self-assembly. This assembly process involves stepwise, uniform increases to the architectural complexity of a substrate, starting from discrete precursors and growing in dimensionality through controlled reactivity to a final product. Herein, two orthogonal processes are exploited: coordination-driven self-assembly and hydrogen bonding. The former relies on the predictable formation of metal–ligand bonds wherein the directionalities of the rigid precursors used determines the structural outcome. The latter uses 2-ureido-4-pyrimidinone interfaces that are structurally robust by virtue of the quadruple hydrogen bonding that can occur between subunits. By combining these two processes into a single system, it is possible to generate hierarchical materials that preserve the attractive tunability associated with discrete supramolecular coordination complexes. For instance, the synthesis of a one-dimensional chain comprising linked metalla-rhomboids is readily adapted to a 2D cross-linked hexagonal network by simply selecting a different metal acceptor precursor as an assembly component. The specific interactions between subunits, in this case platinum(II)-pyridyl bonds and the quadruple H-bonding of ureidopyrimidinone, are unchanged, establishing a unique strategy to obtain supramolecular polymers with marked topological differences with minimal synthetic redesign. In addition, the structural rigidity imposed by the inclusion of the platinum metallacycles serves to minimize the formation of cyclic oligomers, increasing the efficacy of formation and improving the properties of the resultant materials. Furthermore, this study taps the potential of organoplatinum(II) metallacycles in materials science.

Yan, Xuzhou; Li, Shijun; Pollock, James Bryant; Cook, Timothy R.; Chen, Jianzhuang; Zhang, Yanyan; Ji, Xiaofan; Yu, Yihua; Huang, Feihe; Stang, Peter J.

2013-01-01

155

Synthesis and Structural Studies of Diorganotin(IV)-Based Coordination Polymers Bearing Silaalkylphosphonate Ligands and Their Transformation into Colloidal Domains.  

PubMed

The contribution of silaalkylphosphonic acids Me3SiCH2P(O)(OH)2 (1) and Me3SiC(CH3)2P(O)(OH)2 (2) as ligands was demonstrated for the first time by the isolation of new diorganotin(IV) phosphonates Et2Sn{OP(O)(OH)CH2SiMe3}(OSO2Me) (3), (Et2Sn)6{O3PC(CH3)2SiMe3}4(OSO2Me)4 (4), and Et2Sn(O3PCH2SiMe3) (5). X-ray crystallographic studies of 1-4 are presented. The structures of 1 and 2 adopt extended motifs by virtue of P-OH···O?P-type hydrogen bonding interactions. The molecular structure of 3 is composed of a dimer formed by bridging hydrogen phosphonate groups, while the sulfonate group appended on each tin atom acts in a ?2-bridging mode to afford the formation of one-dimensional coordination polymer featuring alternate eight-membered [-Sn-O-P-O-]2 and [-Sn-O-S-O-]2 rings. The asymmetric unit of 4 is composed of two crystallographically unique trinuclear tin phosphonate clusters with a Sn3(?3-PO3)2 core linked together by coordinative association of a ?2-sulfonate group, while the remaining sulfonates are involved in the construction of a two-dimensional self-assembly. The identity of 1-5 in solution was established by IR and multinuclear ((1)H, (13)C, (31)P, (119)Sn) NMR spectroscopy. The presence of silaalkyl group in 5 imparts unusual solubility in hydrocarbon, aromatic, and ether solvents. As a consequence, the formation of colloidal particles of 5 featuring rodlike morphology was achieved by ultrasonication of a solution in ethanol-chloroform mixture. PMID:24854068

Shankar, Ravi; Singla, Nisha; Asija, Meenal; Kociok-Köhn, Gabriele; Molloy, Kieran C

2014-06-16

156

Extending framework based on the linear coordination polymers: Alternative chains containing lanthanum ion and acrylic acid ligand  

NASA Astrophysics Data System (ADS)

One-dimensional alternative chains of two lanthanum complexes: [La( L1) 3(CH 3OH)(H 2O) 2]·5H 2O ( L1=anion of ?-cyano-4-hydroxycinnamic acid ) 1 and [La( L2) 3(H 2O) 2]·3H 2O ( L2=anion of trans-3-(4-methyl-benzoyl)-acrylic acid) 2 were synthesized and structurally characterized by single-crystal X-ray diffraction, element analysis, IR and thermogravimetric analysis. The crystal structure data are as follows for 1: C 31H 36LaN 3O 17, triclinic, P-1, a=9.8279(4) Å, b=11.8278(5) Å, c=17.8730(7) Å, ?=72.7960(10)°, ?=83.3820(10)°, ?=67.1650(10)º, Z=2, R1=0.0377, wR2=0.0746; for 2: C 33H 37LaO 14, triclinic, P-1, a=8.7174(5) Å, b=9.9377(5) Å, c=21.153(2) Å, ?=81.145(2)°, ?=87.591(2)°, ?=67.345(5)°, Z=2, R1=0.0869, wR2=0.220. 1 is a rare example of the alternative chain constructed by syn-syn and anti-syn coordination mode of carboxylato ligand arranged along the chain alternatively. La(III) ions in 2 are linked by two ?3-O bridges and four bridges (two ?2-O and two ?3-O) alternatively. Both of the linear coordination polymers grow into two- and three-dimensional networks by packing through extending hydrogen-bond network directed by ligands.

Li, Hui; Guo, Ming; Tian, Hong; He, Fei-Yue; Lee, Gene-Hsiang; Peng, Shie-Ming

2006-11-01

157

Carbon piezoresistive gauges in one-dimensional stress measurements  

NASA Astrophysics Data System (ADS)

Long rod impact experiments on 2024-T351 aluminum are presented using carbon piezoresistive gauges. The data is reduced using the one-dimensional strain calibration for carbon gauges. From the agreement between the experiments and finite-difference simulations we conclude that the one-dimensional strain calibration for carbon gauges can be used in reducing one-dimensional stress data.

Hari Manoj Simha, C.; Bless, S. J.

1996-05-01

158

Synthesis and characterization of linear cerium(IV) Schiff-base coordination polymers  

SciTech Connect

The first soluble linear Schiff-base rare earth coordination polymer, catena-poly[cerium-(4)-[mu]-N,N[prime],N[double prime],N[prime][double prime]-tetrasalicylidene (3,3[prime]-diaminobenzidinato)-O,N,N[prime],O[prime],O[double prime],N[double prime],N[prime][double prime],O[prime][double prime

Chen, H.; Cronin, J.A.; Archer, R.D. (Univ. of Massachusetts, Amherst, MA (United States). Dept. of Chemistry)

1994-04-11

159

One-dimensional lipid bilayers on carbon nanotubes: Structure and properties  

NASA Astrophysics Data System (ADS)

In this work we report design, assembly, and properties of one-dimensional lipid bilayers wrapped around polymer-coated carbon nanotubes. We propose to use this platform as a tool for interfacing nanomaterials with biological systems. We start by presenting a new general procedure for noncovalent modification of carbon nanotubes based on polyelectrolyte layer-by-layer assembly. We confirm formation of multilayer polymer structures around individual carbon nanotubes by transmission electron microscopy and confocal fluorescence microscopy, and demonstrate that sign of the outmost polymer layer controls surface properties of the multilayer assembly. We study how rigidity of a polymer chain influences its ability to adsorb onto high curvature substrates, such as carbon nanotubes. We then build the one-dimensional lipid bilayer structure by spontaneous assembly of lipid molecules in a continuous nanoshell around a template of a carbon nanotube wrapped with hydrophilic polymer cushion layers. We demonstrate that such one-dimensional lipid membranes are fluid and can heal defects, even over repeated damage-recovery cycles. Measured diffusion coefficients of lipid molecules in our polymer-supported bilayers are about 3 orders of magnitude lower than typical values for fluid lipid membranes, which we attribute to strong electrostatic polyelectrolyte-lipid interactions. To explore the potential for device integration of one-dimensional bilayers we investigate effect of polyelectrolyte multilayers on electrical properties of carbon nanotube transistors. We demonstrate that complex interaction of adsorbed species with the device substrate can produce significant and sometimes unexpected side effects on device characteristics. Finally, we fabricate transistors with suspended carbon nanotube channels and devise a method to transfer them in liquid. It allows us to assemble one-dimensional lipid membranes on carbon nanotube devices, characterize their electrical properties, and thus complete the foundation for a versatile nanobioelectronic device platform.

Artyukhin, Alexander Borisovich

160

Two different 1D-chains in the structures of the copper(I) coordination polymers based on bidentate Schiff-base building units and thiocyanate anions as bridging ligands  

Microsoft Academic Search

The reaction of the bidentate Schiff-base ligands (3,4,5-MeO-ba)2en (L1) and (4-Me-ba)2en (L2) with Cu(SCN) in CH3CN yielded two copper(I) coordination polymers [Cu(L1)(SCN)]n (1) and [Cu(L2)(SCN)]n (2), which have been characterized by elemental analyses, IR- and 1H NMR-spectroscopy, and X-ray crystallography. The non-centrosymmetric structures of both Cu(I) complexes consist of an one-dimensional polymeric chain in which copper(I) ions are bridged by

Aliakbar Dehno Khalaji; Matthias Weil; Hassan Hadadzadeh; Marzieh Daryanavard

2009-01-01

161

One-dimensional lipid bilayers on carbon nanotubes: Structure and properties  

Microsoft Academic Search

In this work we report design, assembly, and properties of one-dimensional lipid bilayers wrapped around polymer-coated carbon nanotubes. We propose to use this platform as a tool for interfacing nanomaterials with biological systems. We start by presenting a new general procedure for noncovalent modification of carbon nanotubes based on polyelectrolyte layer-by-layer assembly. We confirm formation of multilayer polymer structures around

Alexander Borisovich Artyukhin

2007-01-01

162

Synthesis and characterization of nanowire coils of organometallic coordination polymers for controlled cargo release.  

PubMed

Nanowire coils of organometallic coordination polymers have been synthesized for the first time by using the emulsion periphery polymerization technique. An amphiphilic triblock copolymer terminated with inclusion complex of ?-cyclodextrin and 4,4'-bipyridine self-assembles into oil-in-water emulsion in a toluene/water mixture. Subsequent coordination of bipyridine with Ni(II) in periphery of emulsions results in the formation of coordination polymer nanowire coils. The nanowire coils are composed of nanowires with diameter of 2 nm. Nanowire coils exhibit enhanced thermal stability in contrast to their parent triblock copolymer. Interestingly, nanowire coils are capable of encapsulating organic cargoes. Encapsulated cargoes can be selectively extracted from nanowire coils without damaging nanowire coils. Nanowire coils are potential candidates for encapsulating and controlled release of organic cargoes. PMID:24842771

Liang, Guodong; Ni, Huan; Bao, Suping; Zhu, Fangming; Gao, Haiyang; Wu, Qing

2014-06-12

163

Chemical stability and characterization of rhodium-diisocyanide coordination polymers.  

PubMed

Poly-[Rh(1,4-phenylene diisocyanide)+4/2(Cl)-] has a two-dimensional template structure, where Rh atoms are bonded by the -conjugated 1,4-phenylene diisocyanide (pdi) ligands in the x-y plane and through overlapping dz orbitals in the z direction. The more conductive metallic bonds in the z direction create anisotropy in the electrical conductivity. The anisotropy and unique geometry of poly-[Rh(pdi)+4/2(Cl)-] make it a useful test bed for examining the relationship between electrical properties and chemical stability in metal-isocyanide molecular wire systems. The bulk powder of poly-[Rh(pdi)+4/2(Cl)-] is estimated to have a room-temperature bulk conductivity of 3.4 x 10(-11) S x cm(-1), an electrical activation energy of 0.9 eV, and a dielectric constant of 7.5. In this paper, impedance spectroscopy and X-ray powder diffraction were used to show the dependence of the electrical conductivity on the metal-metal bonding of pressed bulk powders of poly-[Rh(pdi)+4/2(Cl)-]. Thermo-gravimetric analysis and X-ray photoelectron spectroscopy were used to demonstrate air sensitivity in the polymer and elucidate the mechanism of oxidative degradation. PMID:18047318

Carson, Cantwell G; Gerhardt, Rosario A; Tannenbaum, Rina

2007-12-27

164

New Ag(I)-iminophosphorane coordination polymers as efficient catalysts precursors for the MW-assisted Meyer-Schuster rearrangement of propargylic alcohols in water.  

PubMed

Treatment of the N-thiophosphorylated iminophosphorane ligands (PTA)?NP(?S)(OR)2 [PTA = 1,3,5-triaza-7-phosphaadamantane, 3a and 3b] and (DAPTA)?NP(?S)(OR)2 [DAPTA = 3,7-diacetyl-1,3,7-triaza-5-bicyclo[3.3.1]nonane, 4a and 4b] with an equimolecular amount of AgSbF6 leads to high-yield formation of the new one-dimensional coordination polymers [Ag{?(2)-N,S-(PTA)?NP(?S)(OR)2}]x[SbF6]x (5a and 5b) and [Ag{?(2)-O,S-(DAPTA)?NP(?S)(OR)2}]x[SbF6]x (6a and 6b), respectively. These new (iminophosphorane)silver(I) coordination polymers are efficient catalyst precursors for the Meyer-Schuster isomerization of both terminal and internal alkynols. Reactions proceeded in water, under aerobic conditions and using microwave irradiation as heating source, to afford the corresponding ?,?-unsaturated carbonyl compounds in excellent yields, without the addition of any cocatalyst. Remarkably, it should be noted that this catalytic system can be recycled up to 10 consecutive runs (1st cycle 45 min, 99%; 10th cycle 6 h, 97%). ESI-MS analysis of 5a in water has been carried out providing valuable insight into the monomeric active species responsible for catalytic activity in water. PMID:23675864

García-Álvarez, Joaquín; Díez, Josefina; Vidal, Cristian; Vicent, Cristian

2013-06-01

165

Virtual high throughput screening confirmed experimentally: porous coordination polymer hydration.  

PubMed

Hydrothermal stability is a pertinent issue to address for many industrial applications where percent levels of water can be present at temperatures ranging from subambient to several hundred degrees. Our objective is to understand relative stabilities of MOF materials through experimental testing combined with molecular modeling. This will enable the ultimate design of materials with improved hydrothermal stability, while maintaining the properties of interest. The tools that we have employed for these studies include quantum mechanical calculations based upon cluster models and combinatorial steaming methods whereby a steam stability map was formulated according to the relative stability of different materials. The experimental steaming method allows for high throughput screening of materials stability over a broad range of steam levels as well as in-depth investigation of structural transformations under more highly resolved conditions, while the cluster model presented here yields the correct trends in hydrothermal stability. Good agreement was observed between predicted relative stabilities of materials by molecular modeling and experimental results. Fundamental information from these studies has provided insight into how metal composition and coordination, chemical functionality of organic linker, framework dimensionality, and interpenetration affect the relative stabilities of PCP materials. This work suggests that the strength of the bond between the metal oxide cluster and the bridging linker is important in determining the hydrothermal stability of the PCP. Although the flexibility of the framework plays a role, it is not as important as the metal-linker bond strength. This demonstration of alignment between experimental and calculated observations has proven the validity of the method, and the insight derived herein insight facilitates direction in designing ideal MOF materials with improved hydrothermal stability for desired applications. PMID:19810730

Low, John J; Benin, Annabelle I; Jakubczak, Paulina; Abrahamian, Jennifer F; Faheem, Syed A; Willis, Richard R

2009-11-01

166

Variations of structures and solid-state conductivity of isomeric silver(I) coordination polymers having linear and V-shaped thiophene-centered ditriazole ligands  

NASA Astrophysics Data System (ADS)

A pair of new linear and V-shaped acceptor-donor-acceptor (A-D-A) thiophene-centered ditriazole structural isomers, i.e., 2,5-di(1H-1,2,4-triazol-1-yl)thiophene (L1) and 3,4-di(1H-1,2,4-triazol-1-yl)thiophene (L2), has been synthesized and characterized. They are used as ?2-bridging ligands to prepare a pair of silver(I) coordination polymers formulated as [Ag(L1)(NO3)]n (1) and [Ag(L2)(NO3)]n (2), which are also structural isomers at the supramolecular level. X-ray single-crystal diffraction analyses for 1 and 2 reveal that they exhibit the same one-dimensional (1D) coordination polymers but different structural architectures because of the distinguishable shape and configuration of isomeric ligands (L1 and L2) and the alterations of the coordination numbers. More interestingly, compared with the free ligands, 1D silver(I) polymeric isomers 1 and 2 show significant enhancement of solid-state conductivity to different extents (1.42×104 and 2.17×103 times), where 6.96 times' enhancement of solid-state conductivity from 1 to 2 has been observed. The formation of Ag-N coordinative bonds and the configurational discrepancy of L1 and L2 are believed to play important roles in facilitating the electron transport between molecules, which can also be supported by Density Function Theory calculations of their band gaps.

Hu, Bin; Geng, Jiao; Zhang, Lie; Huang, Wei

2014-07-01

167

New rational approximants for one-dimensional and quasi-one-dimensional Landau-Ginzburg systems  

SciTech Connect

We study in this paper a technique for extrapolating the high-temperature (weak coupling) expansions towards the strong coupling regime inside the critical region of one- and quasi-one-dimensional Landau-Ginzburg models with two degrees of freedom. This includes a bulk type-II superconductor near H/sub c/2. The procedure combines ideas from the Pade rational-approximants algorithm and from the Borel transform. In contrast to other techniques already applied to the problem, the method proposed has been devised to reproduce correctly both the weak coupling expansion and the leading behavior in the strong coupling region. This leads to systems of nonlinear equations which we have solved in a number of cases. The numerical results for the thermal quantities are compared with exact results and with previous results obtained via other techniques.

Ruggeri, G.J.

1981-02-01

168

Novel 3D bismuth-based coordination polymers: Synthesis, structure, and second harmonic generation properties  

SciTech Connect

Two new 3D bismuth containing coordination polymers are reported along with their single crystal structures and SHG properties. Compound 1: Bi{sub 2}O{sub 2}(pydc) (pydc=pyridine-2, 5-dicarboxylate), crystallizes in the monoclinic, polar space group, P2{sub 1} (a=9.6479(9) A, b=4.2349(4) A, c=11.9615(11) A, {beta}=109.587(1) Degree-Sign ), which contains Bi{sub 2}O{sub 2} chains that are connected into a 3D structure via the pydc ligands. Compound 2: Bi{sub 4}Na{sub 4}(1R3S-cam){sub 8}(EtOH){sub 3.1}(H{sub 2}O){sub 3.4} (1R3S cam=1R3S-camphoric acid) crystallizes in the monoclinic, polar space group, P2{sub 1} (a=19.0855(7) A, b=13.7706(5) A, c=19.2429(7) A, {beta}=90.701(1) Degree-Sign ) and is a true 3D coordination polymer. These are two example of SHG compounds prepared using unsymmetric ligands (compound 1) or chiral ligands (compound 2), together with metals that often exhibit stereochemically-active lone pairs, such as Bi{sup 3+}, a synthetic approach that resulted in polar, non-centrosymmetric, 3D metal-organic coordination polymer. - Graphical Abstract: Structures of two new, polar, 3D Bismuth(III)-based coordination polymers: Bi{sub 2}O{sub 2}(pydc) (compound 1), and Bi{sub 4}Na{sub 4}(1R3S-cam){sub 8}(EtOH){sub 3.1}(H{sub 2}O){sub 3.4} (compound 2). Highlights: Black-Right-Pointing-Pointer New, polar, 3D Bismuth(III)-based coordination polymers. Black-Right-Pointing-Pointer First polar bismuth-based coordination polymers synthesized via a 'hybrid' strategy. Black-Right-Pointing-Pointer Combination of stereochemically-active lone pairs and unsymmetrical or chiral ligands. Black-Right-Pointing-Pointer Synthesis of class C-SHG materials based on Kurtz-Perry categories.

Wibowo, Arief C.; Smith, Mark D. [Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, SC 29208 (United States)] [Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, SC 29208 (United States); Yeon, Jeongho; Halasyamani, P. Shiv [Department of Chemistry, University of Houston, 136 Fleming Building, Houston, TX 77204-5003 (United States)] [Department of Chemistry, University of Houston, 136 Fleming Building, Houston, TX 77204-5003 (United States); Loye, Hans-Conrad zur, E-mail: zurloye@mail.chem.sc.edu [Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, SC 29208 (United States)

2012-11-15

169

Adaptive Moving Grid Strategies for One-Dimensional Systems of Partial Differential Equations.  

National Technical Information Service (NTIS)

Recently a scheme has been proposed for choosing a moving mesh based on minimizing the time rate of change of the solution in the moving coordinates for one-dimensional systems of PDEs. In this paper we show how to apply this idea to systems where the tim...

L. R. Petzold

1987-01-01

170

One-dimensional zinc oxide nanomaterials synthesis and photovoltaic applications  

NASA Astrophysics Data System (ADS)

As humanly engineered materials systems approach the atomic scale, top-down manufacturing approaches breakdown and following nature's example, bottom-up or self-assembly methods have the potential to emerge as the dominant paradigm. Synthesis of one-dimensional nanomaterials takes advantage of such self-assembly manufacturing techniques, but until now most efforts have relied on high temperature vapor phase schemes which are limited in scalability and compatibility with organic materials. The solution-phase approach is an attractive low temperature alternative to overcome these shortcomings. To this end, this thesis is a study of the rationale solution-phase synthesis of ZnO nanowires and applications in photovoltaics. The following thesis goals have been achieved: rationale synthesis of a single ZnO nanowire on a polymer substrate without seeding, design of a wafer-scale technique to control ZnO nanowire array density using layer-by-layer polymers, determination of optimal nanowire field emitter density to maximize the field enhancement factor, design of bridged nanowires across metal electrodes to order to circumvent post-synthesis manipulation steps, electrical characterization of bridged nanowires, rationale solution-phase synthesis of long ZnO nanowires on optical fibers, fabrication of ZnO nanowire dye-sensitized solar cells on optical fibers, electrical and optical characterization of solar cell devices, comparison studies of 2-D versus 3-D nanowire dye-sensitized solar cell devices, and achievement of 6-fold solar cell power conversion efficiency enhancement using a 3-D approach. The thesis results have implications in nanomanufacturing scale-up and next generation photovoltaics.

Weintraub, Benjamin A.

171

Solid-state structural transformations and photoreactivity of 1D-ladder coordination polymers of Pb(II).  

PubMed

An attempt has been made to design double-stranded ladder-like coordination polymers (CPs) of hemidirected Pb(II) . Four CPs, [Pb(?-bpe)(O2 C-C6 H5 )2 ]?2H2 O (1), [Pb2 (?-bpe)2 (?-O2 C-C6 H5 )2 (O2 C-C6 H5 )2 ] (2), [Pb2 (?-bpe)2 (?-O2 C-p-Tol)2 (O2 C-p-Tol)2 ]? 1.5?H2 O (3) and [Pb2 (?-bpe)2 (?-O2 C-m-Tol)2 (O2 C-m-Tol)2 ] (4) (bpe=1,2-bis(4'-pyridyl)ethylene), have been synthesised and investigated for their solid-state photoreactivity. CPs 2-4, having a parallel orientation of bpe molecules in their ladder structures and being bridged by carboxylates, were found to be photoreactive, whereas CP 1 is a linear one-dimensional (1D) CP with guest water molecules aggregating to form a hydrogen-bonded 1D structure. The linear strands of 1 were found to pair up upon eliminating lattice water molecules by heating, which led to the solid-state structural transformation of photostable linear 1D CP 1 into photoreactive ladder CP 2. In the construction of the double-stranded ladder-like structures, the parallel alignment of C?C bonds in 2-4 is dictated by the chelating and ?2 -?(2) :?(1) bridging modes of the benzoate and toluate ligands. The role of solvents in the formation of such double-stranded ladder-like structures has also been investigated. A single-crystal-to-single-crystal transformation occurred when 4 was irradiated under UV light to form [Pb2 (rctt-tpcb)(?-O2 C-m-Tol)2 (O2 C-m-Tol)2 ] (5). PMID:23418063

Kole, Goutam Kumar; Peedikakkal, Abdul Malik Puthan; Toh, Belinda Mei Fang; Vittal, Jagadese J

2013-03-18

172

Novel three-dimensional coordination polymers of lanthanides with sulfate and oxydiacetic acid.  

PubMed

Three three-dimensional coordination polymers, viz. poly[[diaqua-?4-oxydiacetato-di-?4-sulfato-dipraseodymium(III)] hemihydrate], [Pr2(C4H4O5)(SO4)2(H2O)2]·0.5H2O, (I), poly[[diaquadi-?3-oxydiacetato-?3-sulfato-dineodymium(III)] 1.32-hydrate], [Nd2(C4H4O5)2(SO4)(H2O)2]·1.32H2O, (II), and poly[[diaquadi-?3-oxydiacetato-?3-sulfato-disamarium(III)] 1.32-hydrate], [Sm2(C4H4O5)2(SO4)(H2O)2]·1.32H2O, (III), were obtained by hydrothermal reactions of the respective lanthanide oxides and ZnSO4 with oxydiacetic acid (odaH2). The Nd(3+) and Sm(3+) compounds form isomorphous crystal structures in which the lanthanide cations are nine-coordinate, having a tricapped trigonal prismatic coordination. The Pr(3+) compound has an entirely different crystal structure in which two types of coordination polyhedra are observed, viz. nine-coordinate (trigonal prism) and ten-coordinate (bicapped square antiprism). The sulfate anions show various coordination modes, one of which has only rarely been observed crystallographically to date. PMID:24311500

Prasad, Thazhe Kootteri; Rajasekharan, M V

2013-12-15

173

Direct carbonization of Al-based porous coordination polymer for synthesis of nanoporous carbon.  

PubMed

Nanoporous carbon (NPC) is prepared by direct carbonization of Al-based porous coordination polymers (Al-PCP). By applying the appropriate carbonization temperature, both high surface area and large pore volume are realized for the first time. Our NPC shows much higher porosity than other carbon materials (such as activated carbons and mesoporous carbons). This new type of carbon material exhibits superior sensing capabilities toward toxic aromatic substances. PMID:22280024

Hu, Ming; Reboul, Julien; Furukawa, Shuhei; Torad, Nagy L; Ji, Qingmin; Srinivasu, Pavuluri; Ariga, Katsuhiko; Kitagawa, Susumu; Yamauchi, Yusuke

2012-02-15

174

Coordination polymers for catalysis: enhancement of catalytic activity through hierarchical structuring.  

PubMed

We utilized a novel strategy, hierarchical structuring, to enhance the catalytic activity of coordination polymers. Hierarchical Prussian white crystals with hollow structures and kinked surfaces were synthesized by using a self-aggregation and etching strategy. The hierarchical structure significantly enhanced the catalytic activity of Prussian white in the degradation of methylene blue in comparison to the non-hierarchical Prussian white crystals. PMID:24955441

Bu, Fan-Xing; Hu, Ming; Xu, Li; Meng, Qi; Mao, Gui-Yun; Jiang, Dong-Mei; Jiang, Ji-Sen

2014-07-01

175

Optimised hydrothermal synthesis of multi-dimensional hybrid coordination polymers containing flexible organic ligands  

Microsoft Academic Search

In this paper, we summarise our recent research interest in the hydrothermal synthesis and structural characterisation of multi-dimensional coordination polymers. The use of N-(phosphonomethyl)iminodiacetic acid (also referred to as H4pmida) in the literature as a versatile chelating organic ligand is briefly reviewed. This molecule plays an important role in the formation of centrosymmetric dimeric [V2O2(pmida)2]4? anionic units, which were first

Filipe A. Almeida Paz; João Rocha; Jacek Klinowski; Tito Trindade; Fa-Nian Shi; Luís Mafra

2005-01-01

176

In situ hydrothermal synthesis and structural characterization of two novel Cd II-tetrazole coordination polymers  

NASA Astrophysics Data System (ADS)

The in situ hydrothermal reactions of 4-nitrobenzonitrile with Cd(ClO 4) 2 and CdCl 2 afforded two novel Cd II-tetrazole coordination polymers, 2D network {[Cd(H 2O) 2(4-nptz) 2](H 2O) 2} n ( 1) and 1D double chains [Cd(H 2O) 2(4-nptz) 2] n ( 2). Their synthesis, solid-state structure, and XRPD patterns are reported.

Xiao, Jie; Wang, Wen-Xiang; Lin, Jin-Rui; Zhao, Hong

2009-09-01

177

Novel 3D bismuth-based coordination polymers: Synthesis, structure, and second harmonic generation properties  

NASA Astrophysics Data System (ADS)

Two new 3D bismuth containing coordination polymers are reported along with their single crystal structures and SHG properties. Compound 1: Bi2O2(pydc) (pydc=pyridine-2, 5-dicarboxylate), crystallizes in the monoclinic, polar space group, P21 (a=9.6479(9) Å, b=4.2349(4) Å, c=11.9615(11) Å, ?=109.587(1)°), which contains Bi2O2 chains that are connected into a 3D structure via the pydc ligands. Compound 2: Bi4Na4(1R3S-cam)8(EtOH)3.1(H2O)3.4 (1R3S cam=1R3S-camphoric acid) crystallizes in the monoclinic, polar space group, P21 (a=19.0855(7) Å, b=13.7706(5) Å, c=19.2429(7) Å, ?=90.701(1)°) and is a true 3D coordination polymer. These are two example of SHG compounds prepared using unsymmetric ligands (compound 1) or chiral ligands (compound 2), together with metals that often exhibit stereochemically-active lone pairs, such as Bi3+, a synthetic approach that resulted in polar, non-centrosymmetric, 3D metal-organic coordination polymer.

Wibowo, Arief C.; Smith, Mark D.; Yeon, Jeongho; Halasyamani, P. Shiv; zur Loye, Hans-Conrad

2012-11-01

178

Polymer complexes. LIII. Supramolecular coordination modes and structural of novel sulphadrug complexes  

NASA Astrophysics Data System (ADS)

Novel polymer complexes of copper(II), palladium(II), platinum(II) and cadmium(II) containing homopolymer [4-acrylamido benzene sulphonyl guanidine; (HL)] and various anions (SO 42-, CH 3COO -, NO 3-, Br - or Cl -) have been designed and carried out. Their structures were investigated by elemental analyses, spectral (IR, UV-vis, 1H NMR and ESR) and magnetic moments. The modes of interactions between the ligand and the metals were discussed, where oxygen (of O dbnd S dbnd O group) and nitrogen atom [of imino nitrogen (NH/N) of the guanidine group] are involved in chelation. The homopolymer shows two types of coordination behaviour. In mononuclear polymer complexes 4 and 6- 10, it acts as a neutral bidentate ligand chelated through the NH and O atoms, whereas in the polymer complexes 1- 3, 5 and 11, monobasic bidentate ligand is coordinated through the -N and -O atoms. The poly-chelates are of 1:1/1:2 (metal-homopolymer) stoichiometry and exhibit four coordination. On the basis of electronic spectral data and magnetic susceptibility measurement square planar geometry has been proposed. The ESR spectral data provided information about their structure on the basis Hamiltonian parameters and degree of covalency. From the electron paramagnetic resonance and spectral data, the orbital reduction factors were calculated.

Diab, M. A.; El-Sonbati, A. Z.; Mohamed, R. H.

2010-11-01

179

4,2':6',4''-Terpyridines: diverging and diverse building blocks in coordination polymers and metallomacrocycles.  

PubMed

4,2':6',4''-Terpyridine (4,2':6',4''-tpy) is one of the less well documented isomers of the well-established bis-chelating 2,2':6',2''-terpyridine. The N-donors of the outer rings in 4,2':6',4''-tpy subtend an angle of 120°, leading to a description of 4,2':6',4''-tpy as a divergent ligand. Because it typically binds metal ions through the outer N-donors only, 4,2':6',4''-tpy is an ideal linker for combination with metal nodes (often geometrically flexible d(10) ions) in coordination polymers and metallomacrocyclic complexes. The facile functionalization of terpyridines in the 4'-position allows access to a suite of 4'-X-4,2':6',4''-tpy ligands in which the 4'-substituent, X, can be selected to assist in directing the metal-ligand assembly process. This overview of recent advances in the chemistry of 4,2':6',4''-tpy and its 4'-substituted derivatives looks at relationships within a series of chiral polymers, competition between the formation of metallocyclic complexes versus polymers, and the use of extended aryl systems to encourage the formation of coordination polymers in which ?-stacking of arene domains dominates in the assembly process. Use of metal(ii) acetates is key to the formation of paddle-wheel and larger cluster nodes that direct the assembly of both predetermined and unexpected architectures. PMID:24522847

Housecroft, Catherine E

2014-05-14

180

One-dimensional modelling of `verso' laser cleaning  

Microsoft Academic Search

In this paper we present a one-dimensional model describing the verso laser cleaning technique, already experimentally tested, for particle removal from a substrate. The equation for displacement is treated for a one-dimensional case, and the temporal behaviour of the rear surface deformation is determined. Taking into account the van der Waals adhesion force and elastic deformation of a spherical particle

Francesco Bloisi; Giuseppina di Blasio; Luciano Vicari; Monica Zoncheddu

2006-01-01

181

Topological states in one dimensional solids and photonic crystals  

NASA Astrophysics Data System (ADS)

We show that the band structure of a one-dimensional solid with particle-hole symmetry may be characterized by a topological index that owes its existence to the non-trivial homotopy of the space of non-degenerate real symmetric matrices. Moreover we explicitly demonstrate a theorem linking the topological index to the existence of bound states on the surface of a semi-infinite one dimensional solid. Our analysis is a one-dimensional analogue of the analysis of topological insulators in two and three dimensions by Balents and Moore; our results may be relevant to long molecules that are the one dimensional analogue of topological insulators. We propose the realization of this physics in a one-dimensional photonic crystal. In this case the topology of the bandstructure reveals itself not as a bound surface state but as a Lorentzian feature in the time delay of light that is otherwise perfectly reflected by the photonic crystal.

Atherton, Timothy; Mathur, Harsh

2011-03-01

182

Poly[di-?-glycinato-copper(II)]: a two-dimensional coordination polymer  

PubMed Central

The title coordination polymer, [Cu(C2H4NO2)2]n, is two-dimensional and consists of a distorted octa­hedral copper coordination polyhedron with two bidentate glycine ligands chelating the metal through the O and N atoms in a trans-square-planar configuration. The two axial coordination sites are occupied by carbonyl O atoms of neighbouring glycine mol­ecules. The Cu—O distances for the axial O atoms [2.648?(2) and 2.837?(2)?Å] are considerably longer than both the Cu—O [1.9475?(17) and 1.9483?(18)?Å] and Cu—N [1.988?(2) and 1.948?(2)?Å] distances in the equatorial plane, which indicates a strong Jahn–Teller effect. In the crystal, the two-dimensional networks are arranged parallel to (001) and are linked via N—H?O hydrogen bonds, forming a three-dimensional arrangement.

Gschwind, Fabienne; Jansen, Martin

2011-01-01

183

A responsive supramolecular polymer formed by orthogonal metal-coordination and cryptand-based host-guest interaction.  

PubMed

Herein, a cation responsive linear supramolecular polymer was constructed in an orthogonal fashion by unifying the themes of coordination-driven self-assembly and cryptand-based host-guest interaction. PMID:24609282

Wei, Peifa; Xia, Binyuan; Zhang, Yanyan; Yu, Yihua; Yan, Xuzhou

2014-04-18

184

Micromolding of a Highly Fluorescent Reticular Coordination Polymer: Solvent-Mediated Reconfigurable Polymerization in a Soft Lithographic Mold  

SciTech Connect

Coordination polymerization of pyridine-based ligands and zinc or silver ions was controlled by soft lithographic micromolding in capillaries. The polymer patterns that are produced are highly fluorescent and supramolecularly structured.

Y You; H Yang; J Chung; J Kim; Y Jung; S Park

2011-12-31

185

Coordinates  

NSDL National Science Digital Library

This introduction to the labeling of points on a plane by their Cartesian coordinates can optionally be extended to coordinates in 3-dimensional space, to plane polar coordinates and to 3-dimensional polar coordinates. Students should learn to use Cartesian coordinates (x,y) for defining the position of a point in two dimensions and to use Cartesian coordinates (x,y,z) in 3-dimensional space and learn to appreciate the two ways of defining the z axis. Students should also become familiar with some of the tools and terms used by surveyors such as theodolite, azimuth, elevation, and zenith. Optional items for students familiar with trigonometry and with the theorem of Pythagoras are polar coordinates (r,f ) on the plane, Converting (r,f) to (x,y) and vice versa, at least for r, and Spherical polar coordinates (r,q, f) in 3-dimensional space.

Stern, David

186

THE COMPLEXING INTO METAL-CONTAINING GELATIN-IMMOBILIZED MATRICES AS NOVEL PERSPECTIVE METHOD OF COORDINATION POLYMERS SYNTHESIS. UNCHELATED COORDINATION POLYMERS OF NICKEL (II) AND COPPER(II) WITH DITHIOOXAMIDE  

Microsoft Academic Search

The novel unchelates coordination polymers of Ni(II) and Cu(II) with dithiooxamide have been synthesized under specific complexing conditions which have not been used in coordination chemistry before, namely into a nickel(II)- and copper(II)hexacyanoferrate(II) gelatin-immobilized matrices in contact with the aqueous solution of above organic compound.

Oleg V. Mikhailov

1997-01-01

187

A three-dimensional cadmium(II) coordination polymer: poly[[[?-4,4'-(propane-1,3-diyl)dipyridine-?(2)N:N](?-3,3'-thiodipropionato-?(3)O,O':O)cadmium(II)] monohydrate].  

PubMed

In the title coordination polymer, {[Cd(C6H8O4S)(C13H14N2)]·H2O}n, the Cd(II) atom displays a distorted octahedral coordination, formed by three carboxylate O atoms and one S atom from three different 3,3'-thiodipropionate ligands, and two N atoms from two different 4,4'-(propane-1,3-diyl)dipyridine ligands. The Cd(II) centres are bridged through carboxylate O atoms of 3,3'-thiodipropionate ligands and through N atoms of 4,4'-(propane-1,3-diyl)dipyridine ligands to form two different one-dimensional chains, which intersect to form a two-dimensional layer. These two-dimensional layers are linked by S atoms of 3,3'-thiodipropionate ligands from adjacent layers to form a three-dimensional network. PMID:24992117

Hao, Xiao Min; Chen, Gang; Gu, Chang Sheng; Liu, Ji Wei

2014-07-15

188

Spectroscopy of one-dimensionally inhomogeneous media with quadratic nonlinearity  

SciTech Connect

We present a brief review of the results of fifty years of development efforts in spectroscopy of one-dimensionally inhomogeneous media with quadratic nonlinearity. The recent original results obtained by the authors show the fundamental possibility of determining, from experimental data, the coordinate dependences of complex quadratic susceptibility tensor components of a onedimensionally inhomogeneous (along the z axis) medium with an arbitrary frequency dispersion, if the linear dielectric properties of the medium also vary along the z axis and are described by a diagonal tensor of the linear dielectric constant. It is assumed that the medium in question has the form of a plane-parallel plate, whose surfaces are perpendicular to the direction of the inhomogeneity. Using the example of several components of the tensors X{sup (2)}(z, {omega}{sub 1} {+-} {omega}{sub 2}; {omega}{sub 1}, {+-} {omega}{sub 2}), we describe two methods for finding their spatial profiles, which differ in the interaction geometry of plane monochromatic fundamental waves with frequencies {omega}{sub 1} and {omega}{sub 2}. The both methods are based on assessing the intensity of the waves propagating from the plate at the sum or difference frequency and require measurements over a range of angles of incidence of the fundamental waves. Such measurements include two series of additional estimates of the intensities of the waves generated under special conditions by using the test and additional reference plates, which eliminates the need for complicated phase measurements of the complex amplitudes of the waves at the sum (difference) frequency.

Golubkov, A A; Makarov, Vladimir A

2011-11-30

189

One dimensional time-to-explode (ODTX) in HMX spheres  

SciTech Connect

In a series of papers researchers at Lawrence Livermore National Laboratory (LLNL) have reported measurements of the time to explosion in spheres of various high explosives following a rapid, uniform increase in the surface temperature of the sphere. Due to the spherical symmetry, the time-dependent properties of the explosive (temperature, chemical composition, etc.) are functions of the radial spatial coordinate only; thus the name one-dimensional time-to-explosion (ODTX). The LLNL researchers also report an evolving series of computational modeling results for the ODTX experiments, culminating in those obtained using a sophisticated heat transfer code incorporating accurate descriptions of chemical reaction. Although the chemical reaction mechanism used to describe HMX decomposition is quite simple, the computational results agree very well with the experimental data. In addition to reproducing the magnitude and temperature dependence of the measured times to explosion, the computational results also agree with the results of post reaction visual inspection. The ODTX experiments offer a near-ideal example of a transport process (heat transfer in this case) tightly coupled with chemical reaction. The LLNL computational model clearly captures the important features of the ODTX experiments. An obvious question of interest is to what extent the model and/or its individual components (specifically the chemical reaction mechanism) are applicable to other experimental scenarios. Valid exploration of this question requires accurate understanding of (1) the experimental scenario addressed by the LLNL model and (2) details of the application of the model. The author reports here recent work addressing points (1) and (2).

Breshears, D.

1997-06-02

190

Hydrothermal synthesis of copper coordination polymers based on molybdates: Chemistry issues  

NASA Astrophysics Data System (ADS)

Crystal engineering of metal organic coordination polymers or metal organic frameworks have been attracting unprecedented efforts in the past few years due to potential applications in the area of catalysis, gas separation and storage. Hydrothermal synthesis is a popular soft chemical route employed by a number of researchers to grow suitable single crystals for unambiguous structural characterization. The structural diversity of the various solid frameworks is attributed to the choice of metal, its ability to exist in multiple oxidation states exhibiting different coordination geometry and multidentate nature of organic ligands. Polyoxomolybdate is another interesting class of inorganic materials that are potential catalysts. A contemporary theme is to develop porous solids combining the acidic properties of oligomeric molybdates integrated with first-row transition metal ions that can form coordination polymers with suitable multidentate ligands. A bottleneck to this problem is to develop reliable synthetic protocols that can produce reproducible materials with designed structural characteristics. In this paper, we present our results on the formation of self-assembled metal organic hybrid solids from acidified aqueous molybdate solution containing cupric ions and one of the multidentate organic ligands (pyrazine, 2-pyrazine carboxylic acid or isonicotinic acid). We propose a molecular mechanism to rationalize the formation of solids.

Pavani, K.; Ramanan, A.; Whittingham, M. S.

2006-08-01

191

Controlling the Dimensionality of On-Surface Coordination Polymers via Endo- or Exoligation.  

PubMed

The formation of on-surface coordination polymers is controlled by the interplay of chemical reactivity and structure of the building blocks, as well as by the orientating role of the substrate registry. Beyond the predetermined patterns of structural assembly, the chemical reactivity of the reactants involved may provide alternative pathways in their aggregation. Organic molecules, which are transformed in a surface reaction, may be subsequently trapped via coordination of homo- or heterometal adatoms, which may also play a role in the molecular transformation. The amino-functionalized perylene derivative, 4,9-diaminoperylene quinone-3,10-diimine (DPDI), undergoes specific levels of dehydrogenation (-1 H2 or -3 H2) depending on the nature of the present adatoms (Fe, Co, Ni or Cu). In this way, the molecule is converted to an endo- or an exoligand, possessing a concave or convex arrangement of ligating atoms, which is decisive for the formation of either 1D or 2D coordination polymers. PMID:24960576

Shchyrba, Aneliia; Wäckerlin, Christian; Nowakowski, Jan; Nowakowska, Sylwia; Björk, Jonas; Fatayer, Shadi; Girovsky, Jan; Nijs, Thomas; Martens, Susanne C; Kleibert, Armin; Stöhr, Meike; Ballav, Nirmalya; Jung, Thomas A; Gade, Lutz H

2014-07-01

192

A review on one-dimensional ternary germanate nanomaterials.  

PubMed

One-dimensional ternary germanate nanomaterials exhibited wide application potential in the fields of magnetic devices, photocatalysis, sensors and lithium ion batteries owing to their good magnetic, photocatalytic, electrochemical and optical properties. The article reviewed the recent progress and patents on one-dimensional ternary germanate nanomaterials. The recent progress and patents on the synthesis of ternary germanate nanowires, nanorods and nanobelts synthesized by thermal evaporation, hydrothermal method and chemical vapor deposition process were demonstrated. The experimental progress and patents on the application of one-dimensional ternary germanate nanomaterials as magnetic devices, electrochemical sensors, photocatalysis and lithium ion batteries were discussed in detail. Finally, the future development direction of one-dimensional ternary germanate nanomaterials for the synthesis and application was also discussed. PMID:23150920

Pei, Li Z; Yang, Yong; Pei, Yin Q; Xie, Yi K

2013-06-01

193

Permeability of a One-Dimensional Potential Barrier.  

National Technical Information Service (NTIS)

A numerical method is described for computing the exact permeability (tunneling probability) for any one-dimensional potential barrier. It is used to test the validity of the widely used approximate formulae for the tunneling factors for truncated parabol...

R. J. Le Roy K. A. Quickert D. J. Le Roy

1970-01-01

194

Progressive melting in confined one-dimensional C60 chains  

NASA Astrophysics Data System (ADS)

C60 fullerenes confined inside single-walled carbon nanotubes form an archetypal one-dimensional system. X-ray diffraction experiments, from room temperature to 1073 K, reveal an increasing melting phenomenon. Detailed analysis of the sawtooth peak characteristic of the fullerene organization allows the quantitative determination of fluctuations in intermolecular distances. The present results validate the predictions of one-dimensional statistical models.

Bousige, Colin; Rols, Stéphane; Paineau, Erwan; Rouzière, Stéphan; Mocuta, Cristian; Verberck, Bart; Wright, Jonathan P.; Kataura, Hiromichi; Launois, Pascale

2012-07-01

195

Elastic media with microstructure. I - One-dimensional models  

Microsoft Academic Search

One-dimensional models of elastic media possessing microstructure are studied, and a nonlocal theory of elasticity is developed. The theoretical models are classified in terms of explicit and implicit nonlocality, weak and strong nonlocality, discrete and continuous structure, simple and complex structure, approximations, and relationships to the classical model of elastic media. Subjects discussed include the one-dimensional quasi-continuum, the dispersion equation,

I. A. Kunin

1982-01-01

196

Marginal mode and stability of one-dimensional stellar systems  

NASA Astrophysics Data System (ADS)

The paper considers self-gravitating one-dimensional stellar systems governed by the coupled equations of Vlasov and Poisson. The marginal mode which is a displacement mode of the system is made completely explicit by using the Bartholomew formalism, and then it is used to show the stability of one-dimensional systems when their distribution function F depending on the energy epsilon satisfies the sufficient condition of stability dF/d epsilon less than 0.

Gillon, D.

1981-06-01

197

Quantum correlation in one-dimensional extended quantum compass model  

NASA Astrophysics Data System (ADS)

We study the correlations in the one-dimensional extended quantum compass model in a transverse magnetic field. By exactly solving the Hamiltonian, we find that the quantum correlation of the ground state of one-dimensional quantum compass model is vanishing. We show that quantum discord can not only locate the quantum critical points, but also discern the orders of phase transitions. Furthermore, entanglement quantified by concurrence is also compared.

You, W. L.

2012-02-01

198

Controlled syntheses, structures and photoluminescence of two europium coordination polymers based on 2,4-dcp (2,4-dichlorophenoxyacetate) and 4,4'-bpy (4,4'-bipyridine) ligands  

NASA Astrophysics Data System (ADS)

Two new one-dimensional europium coordination polymers, namely {[Eu(2,4-dcp)3(H2O)2]·(4,4'-bpy)(H2O)}n (1) and {[Eu(2,4-dcp)3(H2O)2]·(4,4'-bpy)1.5(H2O)2}n (2) were hydrothermally synthesized by controlling the pH of the reaction solution, and were characterized by elemental analysis, IR, TGA, powder X-ray diffraction and single crystal X-ray diffraction. Single-crystal X-ray diffraction studies indicate that the two europium coordination polymers adopt analogous linear chain structures with a {Eu2(2,4-dcp)5(H2O)4}, and a {Eu2(2,4-dcp)6(H2O)4} dimeric repeat units for 1 and 2, respectively. The europium centers of 1 and 2 are also bound to two water molecules resulting in nine-coordinate, distorted tricapped trigonal-prism and monocapped square antiprism geometries, respectively. The pyridine nitrogen atoms of the 4,4'-bpy ligands do not coordinate to the metal centers in complexes 1-2; instead, they direct the formation of 2D sheet networks via hydrogen bonding interactions. Both 1 and 2 emit the intense red characteristic luminescence of Eu3+ ion at room temperature, with long lifetimes of up to 0.8879 and 0.7571 ms, respectively.

Ma, Deyun; Lu, Kuan; Guo, Haifu; Pan, Yong; Liu, Jianqiang

2012-08-01

199

Synthesis, crystal structure, and porosity estimation of hydrated erbium terephthalate coordination polymers.  

PubMed

The reaction of the Er3+ ion with polycarboxylate ligands in gel media leads to coordination polymers exhibiting various structural types and dimensionalities. Five Er3+/1,4-benzenedicarboxylate-based coordination polymers have been obtained in such conditions. Four out of the five are new. Their crystal structures are reported and compared herein. Compound 1, namely, Er2Ter3(H2O)6, where H2Ter symbolizes the terephthalic acid, crystallizes in the space group P1 (No. 2) with a = 7.8373(10) A, b = 9.5854(2) A, c = 10.6931(2) A, alpha = 68.7770(8) degrees, beta = 70.8710(8) degrees, and gamma = 75.3330(12) degrees. It has already been reported elsewhere. The last four compounds are new. Compound 2, namely, Er2Ter3(H2O)6 x 2 H2O, crystallizes in the space group P121/a1 (No. 14) with a = 6.7429(2) A, b = 22.4913(7) A, c = 9.6575(3) A, and beta = 91.6400(18) degrees. Compound 3, namely Er2Ter3(H2O)8 x 2 H2O crystallizes in the space group P1 (No. 2) with a = 7.5391(2) A, b = 10.0533(3) A, c = 10.4578(3) A, alpha = 87.7870(10) degrees, beta = 82.5510(11) degrees, and gamma = 86.2800(16) degrees. Compound 4, namely, Er2Ter3(H2O)6 x 2 H2O crystallizes in the space group C2/c (No. 15) with a = 38.5123(13) A, b = 11.1241(4) A, c = 7.0122(2) A, and beta = 98.634(2) degrees. Compound 5, namely, Er2Ter3(H2O)6 x H2O, crystallizes in the space group P1 (No. 2) with a = 6.8776(10) A, b = 11.0420(2) A, c = 18.5675(3) A, alpha = 84.7240(6) degrees, beta = 81.8380(6) degrees, and gamma = 84.1770(8) degrees. A computational method has also been developed to evaluate the potential porosity of the coordination polymers. This method is described and then applied to the different Er2Ter3(H2O)n coordination polymers previously described. PMID:16813403

Daiguebonne, Carole; Kerbellec, Nicolas; Bernot, Kevin; Gérault, Yves; Deluzet, André; Guillou, Olivier

2006-07-10

200

Two novel 3-D coordination polymers based on isonicotinic acid: Syntheses, crystal structures and fluorescence  

NASA Astrophysics Data System (ADS)

The hydrothermal reactions of isonicotinic acid (HIso) and metal salts yielded two novel 3-D coordination polymers {[Cu 4(Iso) 4( ?3-O) 2(C 2H 5OH) 2]·2C 2H 5OH·C 2H 6N 4} n ( 1), {[Cd(Iso) 2(H 2O)]·OHCCHO} n ( 2), in which 1 was constructed from 32-membered rings and 3-D interpenetrating network of 2 from 42-membered rings. The fluorescent characterizations show the emissions at 565 nm for 1 and 440 nm for 2 possibly assigned to LMCT and IL, respectively.

Liu, Bing; Xu, Ling; Guo, Guocong

2006-03-01

201

Selective Adsorption of CO2 from Light Gas Mixtures Using a Structurally Dynamic Porous Coordination Polymer**  

SciTech Connect

The selective adsorption of CO{sub 2} from mixtures with N{sub 2}, CH{sub 4}, and N{sub 2}O in a dynamic porous coordination polymer (see monomer structure) was evaluated by ATR-FTIR spectroscopy, GC, and SANS. All three techniques indicate highly selective adsorption of CO{sub 2} from CO{sub 2}/CH{sub 4} and CO{sub 2}/N{sub 2} mixtures at 30 C, with no selectivity observed for the CO{sub 2}/N{sub 2}O system.

Kristi L. Kauffman, Jeffrey T. Culp, Andrew J. Allen, Laura Espinal, Winnie Wong-Ng, Thomas D. Brown, Angela Goodman, Mark P. Bernardo, Russel J. Pancoast, Danielle Chirdon, Christopher Matranga*

2010-01-01

202

Electronic, optical, and computational studies of a redox-active napthalenediimide-based coordination polymer.  

PubMed

The new one-dimensional coordination framework (Zn(DMF)NO3)2(NDC)(DPMNI), where NDC = 2,6-naphthalenedicarboxylate and DPMNI = N,N'-bis(4-pyridylmethyl)-1,4,5,8-naphthalenetetracarboxydiimide, which has been crystallographically characterized, exhibits two redox-accessible states due to the successive reduction of the naphthalenediimide (NDI) ligand core. Solid-state electrochemical and vis-near-IR spectroelectrochemical measurements coupled with density functional theory (DFT) calculations enabled the origins of the optical transitions in the spectra of the monoradical anion and dianion states of the material to be assigned. Electron paramagnetic resonance (EPR) spectroscopy revealed that the paramagnetic radical anion state of the DPMNI core could be accessed upon broad-spectrum white light irradiation of the material, revealing a long-lived excited state, possibly stabilized by charge delocalization which arises from extensive ?-?* stacking interactions between alternating NDC and NDI aromatic cores which are separated by a distance of 3.580(2) Å. PMID:24283401

Leong, Chanel F; Chan, Bun; Faust, Thomas B; Turner, Peter; D'Alessandro, Deanna M

2013-12-16

203

Exact solution of the one-dimensional Hubbard model with arbitrary boundary magnetic fields  

NASA Astrophysics Data System (ADS)

The one-dimensional Hubbard model with arbitrary boundary magnetic fields is solved exactly via the Bethe ansatz methods. With the coordinate Bethe ansatz in the charge sector, the second eigenvalue problem associated with the spin sector is constructed. It is shown that the second eigenvalue problem can be transformed into that of the inhomogeneous XXX spin chain with arbitrary boundary fields which can be solved via the off-diagonal Bethe ansatz method.

Li, Yuan-Yuan; Cao, Junpeng; Yang, Wen-Li; Shi, Kangjie; Wang, Yupeng

2014-02-01

204

catena-Poly[[[4-amino-3,5-bis(pyridin-2-yl)-4H-1,2,4-triazole-?(2)N(1),N(5)](dicyanamido-?N)copper(II)]-?2-dicyanamido-?(2)N:N']: coordination polymer chains linked into a bilayer by hydrogen bonds and ?-? stacking interactions.  

PubMed

In the title compound, [Cu(C2N3)2(C12H10N6)]n or [Cu(dca)2(abpt)]n, where abpt is 4-amino-3,5-bis(pyridin-2-yl)-4H-1,2,4-triazole and dca is the dicyanamide anion, the Cu(II) centre is five-coordinate with an approximately square-pyramidal geometry. One of the two dicyanamide ligands is a terminal ligand, but the other one acts as a ?1,5-bridging ligand between pairs of Cu(II) centres, so generating a one-dimensional coordination polymer. A combination of N-H···N and C-H···N hydrogen bonds, augmented by ?-? stacking interactions, links the coordination polymer chains into a bilayer structure. Comparisons are made with some related Cu(II) complexes containing dca ligands and heteroaromatic co-ligands. PMID:24705048

Setifi, Zouaoui; Setifi, Fatima; Saadi, Mohamed; Rouag, Djamil Azzeddine; Glidewell, Christopher

2014-04-01

205

Ligand effects on the structural dimensionality and antibacterial activities of silver-based coordination polymers.  

PubMed

Four Ag-based coordination polymers [Ag(Bim)] (1), [Ag2(NIPH)(HBim)] (2), [Ag6(4-NPTA)(Bim)4] (3) and [Ag2(3-NPTA)(bipy)0.5(H2O)] (4) (HBim = 1H-benzimidazole, bipy = 4,4'-bipyridyl, H2NIPH = 5-nitroisophthalic acid, H2NPTA = 3-/4-nitrophthalic acid) have been synthesized by hydrothermal reaction of Ag(i) salts with N-/O-donor ligands. Single-crystal X-ray diffraction indicated that these coordination polymers constructed from mononuclear or polynuclear silver building blocks exhibit three typical structure features from 1-D to 3-D frameworks. These compounds favour a slow release of Ag(+) ions leading to excellent and long-term antimicrobial activities, which is distinguished by their different topological structures, towards both Gram-negative bacteria, Escherichia coli (E. coli) and Gram-positive bacteria, Staphylococcus aureus (S. aureus). In addition, these compounds show good thermal stability and light stability under UV-vis and visible light, which are important characteristics for their further application in antibacterial agents. PMID:24871812

Lu, Xinyi; Ye, Junwei; Sun, Yuan; Bogale, Raji Feyisa; Zhao, Limei; Tian, Peng; Ning, Guiling

2014-07-14

206

Quantum solution for the one-dimensional Coulomb problem  

SciTech Connect

The one-dimensional hydrogen atom has been a much studied system with a wide range of applications. Since the pioneering work of Loudon [R. Loudon, Am. J. Phys. 27, 649 (1959).], a number of different features related to the nature of the eigenfunctions have been found. However, many of the claims made throughout the years in this regard are not correct--such as the existence of only odd eigenstates or of an infinite binding-energy ground state. We explicitly show that the one-dimensional hydrogen atom does not admit a ground state of infinite binding energy and that the one-dimensional Coulomb potential is not its own supersymmetric partner. Furthermore, we argue that at the root of many such false claims lies the omission of a superselection rule that effectively separates the right side from the left side of the singularity of the Coulomb potential.

Nunez-Yepez, H. N.; Salas-Brito, A. L.; Solis, Didier A. [Departamento de Fisica, Universidad Autonoma Metropolitana, Unidad Iztapalapa, Apartado Postal 55-534, Iztapalapa CP 09340 D. F. (Mexico); Departamento de Ciencias Basicas, Universidad Autonoma Metropolitana, Unidad Azcapotzalco, Apartado Postal 21-267, Coyoacan CP 04000 D. F. (Mexico); Facultad de Matematicas, Universidad Autonoma de Yucatan, Periferico Norte Tablaje C. 13615, Merida, Yucatan (Mexico)

2011-06-15

207

One-dimensional rainbow thermometry system by using slit apertures.  

PubMed

A new rainbow thermometry system by using slit apertures and a laser light sheet, called a one-dimensional rainbow thermometry (ORT) system, has been developed as an extension of global rainbow thermometry (GRT). This system is capable of one-dimensional or line measurements of the size and refractive index of droplets in the spray space, while the conventional GRT system is normally considered a typical "single-point" or "small volume" measurement method. The performance of this new system was tested and verified with both water and ethanol spray. The results show the feasibility and potential of ORT in simultaneous and one-dimensional measurement of the size and refractive index of liquid droplets, especially in the research field of spray evaporation and combustion. PMID:24487885

Wu, Xuecheng; Jiang, Haoyu; Wu, Yingchun; Song, Jin; Gréhan, Gérard; Saengkaew, Sawitree; Chen, Linghong; Gao, Xiang; Cen, Kefa

2014-02-01

208

Metal dicyanamide layered coordination polymers with cyanopyridine co-ligands: Synthesis, crystal structures and magnetism  

SciTech Connect

A series of metal dicyanamide (dca) coordination polymers combined with cyanopyridine (cypy) terminal co-ligands, namely, [Co{sub 2}(dca){sub 4}(4-cypy){sub 4}] {sub n} (1), [Cd(dca){sub 2}(4-cypy){sub 2}] {sub n} (2), [Fe(dca){sub 2}(3-cypy){sub 2}] {sub n} (3) and [Co(dca){sub 2}(3-cypy){sub 2}] {sub n} (4), have been synthesized at the ambient conditions. X-ray single crystal diffraction reveals that complexes 1-4 have similar metal-dca coordination layers in which the octahedral metal centers are connected by {mu} {sub 1,5}-dca linkers. Notably, three types of 3-D packing lattices are observed for these layered arrays. The thermal stabilities of such new crystalline materials have been studied by thermogravimetric analysis of mass loss. The magnetic properties of the Co{sup II} and Fe{sup II} complexes have been investigated and discussed in detail. A discrete mononuclear molecule [Cd(dca){sub 2}(pyom){sub 2}] (5) is also described, in which the chelated ligand O-methyl picolinimidate (pyom) arises from the addition of methanol solvent across the C{identical_to}N bond of 2-cypy. - Graphical abstract: A series of new metal dicyanamide complexes with cyanopyridine terminal co-ligands have been prepared and structurally determined by X-ray single-crystal diffraction. The magnetic properties of the Co{sup II} and Fe{sup II} layered coordination polymers are also discussed.

Du Miao [College of Chemistry and Life Science, Tianjin Normal University, Tianjin 300074 (China)]. E-mail: dumiao@public.tpt.tj.cn; Wang Qian [College of Chemistry and Life Science, Tianjin Normal University, Tianjin 300074 (China); Wang Ying [College of Chemistry and Life Science, Tianjin Normal University, Tianjin 300074 (China); Zhao Xiaojun [College of Chemistry and Life Science, Tianjin Normal University, Tianjin 300074 (China); Ribas, Joan [Departament de Quimica Inorganica, Universitat de Barcelona, Diagonal, 647, 08028-Barcelona (Spain)

2006-12-15

209

Poly[di-?-glycinato-copper(II)]: a two-dimensional coordination polymer.  

PubMed

The title coordination polymer, [Cu(C(2)H(4)NO(2))(2)](n), is two-dimensional and consists of a distorted octa-hedral copper coordination polyhedron with two bidentate glycine ligands chelating the metal through the O and N atoms in a trans-square-planar configuration. The two axial coordination sites are occupied by carbonyl O atoms of neighbouring glycine mol-ecules. The Cu-O distances for the axial O atoms [2.648?(2) and 2.837?(2)?Å] are considerably longer than both the Cu-O [1.9475?(17) and 1.9483?(18)?Å] and Cu-N [1.988?(2) and 1.948?(2)?Å] distances in the equatorial plane, which indicates a strong Jahn-Teller effect. In the crystal, the two-dimensional networks are arranged parallel to (001) and are linked via N-H?O hydrogen bonds, forming a three-dimensional arrangement. PMID:22058852

Gschwind, Fabienne; Jansen, Martin

2011-09-01

210

Oxamato-based coordination polymers: recent advances in multifunctional magnetic materials.  

PubMed

The design and synthesis of novel examples of multifunctional magnetic materials based on the so-called coordination polymers (CPs) have become very attractive for chemists and physicists due to their potential applications in nanoscience and nanotechnology. However, their preparation is still an experimental challenge, which requires a deep knowledge of coordination chemistry and large skills in organic chemistry. The recent advances in this field using a molecular-programmed approach based on rational self-assembly methods which fully exploit the versatility of the coordination chemistry of the barely explored and evergreen family of N-substituted aromatic oligo(oxamato) ligands are presented in this feature article. These exploratory studies have revealed a wide variety of interesting multifunctional magnetic materials such as optically-active chiral and luminescent magnets or dynamic porous magnets as candidates for chemical sensing. Our feeling, however, is that we have only scratched the surface of the topic and that there are many more exciting brand-new molecule-based materials waiting to be discovered. PMID:24727906

Grancha, Thais; Ferrando-Soria, Jesús; Castellano, María; Julve, Miguel; Pasán, Jorge; Armentano, Donatella; Pardo, Emilio

2014-06-19

211

In situ Oxidation of phenol and o-aminophenol in the channels of 3d-supramolecular coordination polymers  

NASA Astrophysics Data System (ADS)

The host attractive properties of supramolecular coordination polymers of the type _infty^3 [(R3Sn)3FeIII(CN)6], where R = methyl (I), n-butyl (II), and phenyl (III), afford the ability to be used as effective oxidizing reagents for phenol and o-aminophenol forming new host-guest supramolecular coordination polymers. Phenol was oxidized to 1,4-benzoquinone while o-aminophenol was oxidized to poly-o-aminophenol by the polymers I and II and to 2-aminophenoxazin-3-one by the polymer III. The oxidation products were investigated by methods of spectroscopy and high-performance liquid chromatography. The redox reactions were characterized by first-order kinetics. Moreover, mechanisms of the oxidation processes of phenol and o-aminophenol have been proposed.

Etaiw, Safaa El-Din H.; Werida, Amal H.

2010-09-01

212

One-dimensional kinematic model of preferred orientation development  

Microsoft Academic Search

The one-dimensional model to analyse the kinematics of crystallographic preferred orientation of Ribe (1989)is presented and developed further. It is argued that this approach can be applied to rotational deformations where the predominant deformation mechanism is grain boundary sliding. Two contrasting situations are distinguished. The first is where lattice rotations of opposing sense occur and there are orientations for which

Martin Casey; Allen J. McGrew

1999-01-01

213

One-dimensional conversion of color temperature in perceived illumination  

Microsoft Academic Search

This paper proposes one-dimensional conversion of color temperature in perceived illumination. It also presents the design and implementation of the method. The method is demonstrated experimentally for color temperatures in the range of 3000°K to 25000°K. The proposed method is realized by using the Xilinx Virtex FPGA XCV 2000E-6BG560

Honam Lee; Hyungjin Choi; Bonggeun Lee; Bongsoon Kang

2001-01-01

214

One-Dimensional Model of Optically Induced Thermoelastic Waves  

Microsoft Academic Search

A one-dimensional model of the generation of thermoelastic waves by light beam absorption in solids is described and solved. The exact thermal and mechanical boundary conditions are used. An analytical asymptotic solution of the problem is obtained. The relation between the maximum displacement of the second surface of the sample and the duration of the incident light pulse is determined.

J. Mozina; M. Dovc

1994-01-01

215

A quasi-one-dimensional model for cascade gasdynamic lasers  

Microsoft Academic Search

A quasi-one-dimensional model for cascade 16-µm gasdynamic lasers is developed. Based on this model, the effect of cavity parameters on the output pulse is studied. Also, a comparison with externally pumped lasers is made. It is shown that this type of 16-µm gasdynamic lasers can substitute the externally pumped lasers without encountering any difficulties.

A. R. Bahrampour; R.-M. Farrahi

2003-01-01

216

Vanishing Viscosity Method in One-Dimensional Thermoelasticity.  

National Technical Information Service (NTIS)

The vanishing viscosity method is applied to the system of conservation laws of mass, momentum, and energy for a special class of one-dimensional thermoelastic media that do not conduct heat. Two types of vanishing 'viscosity' are considered: Newtonian an...

G. Q. Chen C. M. Dafermos

1994-01-01

217

Adiabatic Oscillations of the One-Dimensional SGEMP Boundary Layer  

Microsoft Academic Search

Adiabatic oscillations of the one-dimensional SGEMP boundary layer about equilibrium are described in a fluid approximation. The solution for monoenergetic emission normal to the surface is found and compared with a computer solution. Solutions for photoelectron emission with a cosine distribution for a monoenergetic and a linear times exponential energy distribution are also found. It appears that these latter solutions

Roger Stettner

1977-01-01

218

One-Dimensional NOE Experiments Using Pulsed Field Gradients  

Microsoft Academic Search

Previously, it has been shown that the use of pulsed field gradients in one-dimensional NOE experiments results in spectra of much higher quality than it has previously been possible to record. Such high-quality spectra make it possible to measure, with complete confidence, very small NOE enhancements and also make it straightforward to measure NOE buildup curves. In this paper, the

Katherine Stott; James Keeler; Que N. Van; A. J. Shaka

1997-01-01

219

A Variational Approach to One Dimensional Phase Unwrapping  

Microsoft Academic Search

Abstract: have been developed and formulated in a discretesetting. Here we propose a variational formulation to solvethe problem. This continuous framework will allow us toimpose some constraints on the smoothness of the solutionand to implement them efficiently. This method is presentedin the one dimensional case, and will serve as a basis forfuture developments in the real 2D case.

Caroline Lacombe; Pierre Kornprobst; Gilles Aubert; Laure Blanc-féraud

2002-01-01

220

Distances on a one-dimensional lattice from noncommutative geometry  

Microsoft Academic Search

In this Letter, we continue the work of Bimonte, Lizzi and Sparano on distances on a one-dimensional lattice. We succeed in analytically proving the exact formulae for such distances. We find that the distance to an even point on the lattice is the geometrical average of the ‘predecessor’ and ‘successor’ distances to the neighbouring odd points.

E. Atzmon; Beverly Sackler

1996-01-01

221

A One-dimensional Time Dependent Cloud Model  

Microsoft Academic Search

A one-dimensional prognostic cloud model has been developed for possible use in a Cumulus Param- eterization Scheme (CPS). In this model, the nonhydrostatic pressure, entrainment, cloud microphysics, lateral eddy mixing and vertical eddy mixing are included, and their effects are discussed. The inclusion of the nonhydrostatic pressure can (1) weaken vertical velocities, (2) help the cloud de- velop sooner, (3)

Shu-Hua CHEN; Wen-Yih SUN

2002-01-01

222

Intrinsic dephasing in one-dimensional ultracold atom interferometers  

Microsoft Academic Search

Quantum phase fluctuations play a crucial role in low dimensional systems. In particular they prevent true long range phase order from forming in one dimensional condensates, even at zero temperature. Nevertheless, by dynamically splitting the condensate into two parallel decoupled tubes, a macroscopic relative phase, can be imposed on the system. This kind of setup can serve as a matter

Rafi Bistritzer; Ehud Altman

2007-01-01

223

An Efficient One-Dimensional Fractal Analysis for Iris Recognition  

Microsoft Academic Search

An iris recognition system is proposed in this paper. This system implements (a) the combination of proposed black hole search method and integro-differential operators for iris localization, (b) one-dimensional fractal analysis for feature extraction and (c) dissimilarity operator for matching. The black hole search method achieves 100% accuracy of pupil detection for both CASIA and MMU Iris databases. Experiment results

Chuan Chin Teo; Hong Tat Ewe

2005-01-01

224

One-Dimensional Ising Model with "k"-Spin Interactions  

ERIC Educational Resources Information Center

We examine a generalization of the one-dimensional Ising model involving interactions among neighbourhoods of "k" adjacent spins. The model is solved by exploiting a connection to an interesting computational problem that we call ""k"-SAT on a ring", and is shown to be equivalent to the nearest-neighbour Ising model in the absence of an external…

Fan, Yale

2011-01-01

225

On boundary controllability of one-dimensional vibrating systems  

Microsoft Academic Search

In this paper boundary controllability of one-dimensional vibrating system such as the vibrating string or the vibrating beam is studied. In particular we are concerned with the question whether it is possible to transfer a given initial state of vibration into rest within a given time such that the system stays in rest when the control is turned off. This

W. Krabs; E. Meister

1979-01-01

226

Photonic dispersion relation in a one-dimensional quasicrystal  

Microsoft Academic Search

The dispersion relation of photons transmitting through a photonic one-dimensional quasicrystal arranged in a Fibonacci sequence was observed by measuring the spectrum of the phase change of the transmitted light using a Michelson-type interferometer. The phase spectrum obtained clearly showed the self-similar structure characteristic to dispersion curves of Fibonacci lattices.

Toshiaki Hattori; Noriaki Tsurumachi; Sakae Kawato; Hiroki Nakatsuka

1994-01-01

227

PREMIXED ONE-DIMENSIONAL FLAME (PROF) CODE USER'S MANUAL  

EPA Science Inventory

The report is a user's manual that describes the problems that can be treated by the Premixed One-dimensional Flame (PROF) code. It also describes the mathematical models and solution procedures applied to these problems. Complete input instructions and a description of output ar...

228

Theory of the one-dimensional forest-fire model  

SciTech Connect

Turbulent cascade processes are studied in terms of a one-dimensional forest-fire model. A hier- archy of steady-state equations for the forests and the holes between them is constructed and solved within a mean-field closure scheme. The exact hole distribution function is found to be [ital N][sub [ital H

Paczuski, M.; Bak, P. (Department of Physics, Brookhaven National Laboratory, Upton, New York 11973 (United States))

1993-11-01

229

Irregular Dynamics of an Open One-Dimensional Mechanical System  

Microsoft Academic Search

We study the dynamics of a one-dimensional system - a network of hard spheres connected by springs. The spheres enter through an inlet with initial velocity, experience a drag force, and are pulled through an outlet. Our computer simulations show irregular dynamics, even when the average number of spheres within the chamber is small. This irregular dynamics is possibly a

Austin Gerig; Alfred Hubler

2003-01-01

230

One-Dimensional Model for Pulverized Coal Combustion and Gasification  

Microsoft Academic Search

A one-dimensional model has been developed for pulverized coal combustors and gasifiers. The model describes the response of a coal particle system to its thermal, chemical and physical environment. Moisture vaporization, coal devolatilization, heterogeneous char oxidation, gas particle interchange, radiation, gas phase oxidation, primary and secondary stream mixing, and heat losses are considered. A predictor-corrector solution technique was used to

PHILIP J. SMITH; L. DOUGLAS SMOOT

1980-01-01

231

One Dimensional Random Walk with a Partially Reflecting Barrier  

Microsoft Academic Search

In the present paper we consider the one dimensional random walk of a particle restricted by a partially reflecting barrier. The reflecting barrier is described by a coefficient of reflection $r$. The probability of finding a particle at a lattice point $m$ after $N$ steps is calculated and expressed in terms of hypergeometric functions of the $_2F_1$-type. Other theorems are

G. Lehner

1963-01-01

232

Teaching Module for One-Dimensional, Transient Conduction.  

ERIC Educational Resources Information Center

Describes a PC-based teaching module designed to instruct engineering students in transient one-dimensional conduction heat transfer analysis. The discussion considers problem formulation, nondimensionalization, discretization, numerical stability and the time-step restriction, program operation, and program verification. (MES)

Ribando, Robert J.; O'Leary, Gerald W.

1998-01-01

233

Statistical mechanics of a one-dimensional lattice gas  

Microsoft Academic Search

We study the statistical mechanics of an infinite one-dimensional classical lattice gas. Extending a result ofvan Hove we show that, for a large class of interactions, such a system has no phase transition. The equilibrium state of the system is represented by a measure which is invariant under the effect of lattice translations. The dynamical system defined by this invariant

D. Ruelle

1968-01-01

234

Quantum Correlation in One-dimensional Extend Quantum Compass Model  

Microsoft Academic Search

We study the quantum correlations in one-dimensional extended quantum compass model. We show that quantum discord can not only locate the quantum critical points, but also discern the orders of phase transitions. Furthermore, entanglement quantified by concurrence is also compared.

Wen-Long You

2011-01-01

235

Spatial Ordering Derivation for One-Dimensional Wireless Sensor Networks  

Microsoft Academic Search

Sensors can be deployed along a road or bridge to form a one-dimensional wireless sensor network where nodes have a spatial ordering. This spatial characteristic indicates relative locations for nodes and facilitates functions like object tracking and monitoring in the network. We target at deriving this ordering without attaching extra hardware to sensor nodes. In this work, we propose to

Xiaojun Zhu; Guihai Chen

2011-01-01

236

One-Dimensional Thermomechanical Constitutive Relations for Shape Memory Materials  

Microsoft Academic Search

The use of the thermoelastic martensitic transformation and its reverse transformation has recently been proposed and demonstrated for several active control ap plications. However, the present constitutive models have lacked several important funda mental concepts that are essential for many of the proposed intelligent material system ap plications such as shape memory hybrid composites.A complete, unified, one-dimensional constitutive model of

C. Liang; C. A. Rogers

1990-01-01

237

Secure communication via one-dimensional chaotic inverse systems  

Microsoft Academic Search

in chaotic secure communications, even one-dimensional discrete chaotic systems are able to provide a high level of security. This paper demonstrates that in the way of chaotic inverse system approach, a class of piecewise linear chaotic systems can provide better encryption performances than most other chaotic cryptosystems, such as uniform distribution, ?-like correlation function, sensitivity to parameter mismatch, and high

Hong Zhou; Xie-Tang Ling; Juii Yu

1997-01-01

238

Statistical properties of one-dimensional Bose gas  

SciTech Connect

The Monte Carlo method within the so-called classical field approximation is applied to one-dimensional, weakly interacting, repulsive Bose gas trapped in a harmonic potential. Equilibrium statistical properties of the condensate are calculated within a canonical ensemble. We also calculate experimentally relevant, low-order correlation functions of the whole gas.

Bienias, Przemyslaw; Pawlowski, Krzysztof; Gajda, Mariusz; RzaPzewski, Kazimierz [Center for Theoretical Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, 02-668 Warsaw (Poland); Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, 02-668 Warsaw (Poland); Center for Theoretical Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, 02-668 Warsaw, Poland and Faculty of Mathematics and Sciences, Cardinal Stefan Wyszynski University, ulica Dewajtis 5, 01-815 Warsaw (Poland)

2011-03-15

239

Variational iteration method for one dimensional nonlinear thermoelasticity  

Microsoft Academic Search

This paper applies the variational iteration method to solve the Cauchy problem arising in one dimensional nonlinear thermoelasticity. The advantage of this method is to overcome the difficulty of calculation of Adomian’s polynomials in the Adomian’s decomposition method. The numerical results of this method are compared with the exact solution of an artificial model to show the efficiency of the

N. H. Sweilam; M. M. Khader

2007-01-01

240

Two multi-dimensional frameworks constructed from zinc coordination polymers with pyridine carboxylic acids  

SciTech Connect

Two novel zinc coordination polymers [Zn{sub 2}(H{sub 2}O)L(MoO{sub 4})]{sub n} (1) and [Zn{sub 4}(PO{sub 4}){sub 2}L'(H{sub 2}O)]{sub n} (2) (H{sub 2}L=2,2'-bipyridine-6.6'-dicarboxylic acid, H{sub 2}L'=2,2'-bipyridine-4,4'-dicarboxylic acid) have been hydrothermally synthesized and characterized by elemental analyses, IR spectra, UV spectra, single-crystal X-ray diffraction and thermogravimetric analyses. Structural analyses indicate that 1 represents a 2-D sheet structure built by dimeric [Zn{sub 2}L(H{sub 2}O)]{sup 2+} units and MoO{sub 4}{sup 2-} groups whereas 2 displays an interesting 3-D framework constructed by tetranuclear zinc clusters, L'{sup 2-} ligands and PO{sub 4}{sup 3-} groups. Examination of UV spectra suggests that both 1 and 2 can stably exist in the pH range of 2.45-5.45 and 3.01-8.55 in aqueous solution, respectively. The room-temperature solid-state photoluminescence of 1 and 2 are derived from the intra-ligands {pi}-{pi}* transitions of H{sub 2}L and H{sub 2}L' ligands and the ligand-to-metal-charge-transfer transitions. - Graphical Abstract: Two new transition metal coordination polymers, namely, [Zn{sub 2}(H{sub 2}O)L{sub 1}(MoO{sub 4})]{sub n} (1), [Zn{sub 4}(PO{sub 4}){sub 2}L{sub 2}(H{sub 2}O)]{sub n} (2) (H{sub 2}L{sub 1}=2,2'-bipyridine-6,6'-dicarboxylic acid, H{sub 2}L{sub 2}=2,2'-bipyridine-4,4'-dicarboxylic acid) have been hydrothermally synthesized. 1 represents a 2-D sheet structure while 2 represents 3-D network. Highlights: {yields}Two new transition metal coordination polymers have been hydrothermally synthesized. > The two compounds have been characterized by elemental analyses, IR, UV spectra, single-crystal X-ray diffraction, thermogravimetric analyses and photoluminescence. > Compound 1 represents a 2-D sheet structure while 2 represents 3-D network.

Guo Yuanyuan; Ma Pengtao [Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004 (China); Wang Jingping, E-mail: jpwang@henu.edu.cn [Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004 (China); Niu Jingyang, E-mail: jyniu@henu.edu.cn [Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004 (China)

2011-11-15

241

Nucleon-nucleon cross sections via stochastic processes in phase space: One-dimensional scattering  

NASA Astrophysics Data System (ADS)

One-dimensional nucleon-nucleon scattering is simulated by Monte Carlo techniques in the quasiclassical approximation of the Wigner representation. Nucleons are represented by minimum wave packets of approximate nucleon radii, their linear dispersion offset by intrinsic harmonic oscillation, inducing phase space spin in the nucleon Wigner function. A representative set of points evolve in four-dimensional phase space in deterministic classical and stochastic quantum momentum jumps. In the extended space, the inter-nucleon one-pion exchange potential is defined locally by the point coordinates. By the geometric analogy, cross sections are computed from collision distances considered as impact parameters. Results from the parameter free one-dimensional simulation show reasonable agreement with empirical data in the energy range 0.01 GeV to 5 GeV.

John, Sarah

2007-07-01

242

Linear alkaline earth metal phosphinate coordination polymers: synthesis and structural characterization.  

PubMed

Reaction of alkaline earth metal salts with diphenylphosphinic acid in dimethylformamide solvent afforded four coordination polymers: [Mg3(O2PPh2)6(DMF)2]·2DMF (I), [Ca(O2PPh2)2(DMF)2] (II), [Sr(O2PPh2)2(DMF)2] (III) and [Ba(O2PPh2)2(DMF)2] (IV) (where DMF is N,N-dimethylformamide). Single-crystal X-ray diffraction revealed that all four compounds produce linear chain structures in the solid state, with the Ca, Sr and Ba forming isostructural crystals. The bulk materials were characterized by FT-IR and (1)H NMR spectroscopy and elemental analyses. PMID:24892607

Rood, Jeffrey A; Huttenstine, Ashley L; Schmidt, Zachery A; White, Michael R; Oliver, Allen G

2014-06-01

243

Fast and persistent electrocatalytic water oxidation by Co-Fe Prussian blue coordination polymers.  

PubMed

The lack of an efficient, robust, and inexpensive water oxidation catalyst (WOC) is arguably the biggest challenge for the technological development of artificial photosynthesis devices. Here we report the catalytic activity found in a cobalt hexacyanoferrate (CoHCF) Prussian blue-type coordination polymer. This material is competitive with state-of-the-art metal oxides and exhibits an unparalleled long-term stability at neutral pH and ambient conditions, maintaining constant catalytic rates for weeks. In addition to its remarkable catalytic activity, CoHCF adds the typical properties of molecule-based materials: transparency to visible light, porosity, flexibility, processability, and low density. Such features make CoHCF a promising WOC candidate for advancement in solar fuels production. PMID:23978044

Pintado, Sara; Goberna-Ferrón, Sara; Escudero-Adán, Eduardo C; Galán-Mascarós, José Ramón

2013-09-11

244

Two Novel Diamagnetic-metal Coordination Polymers of Nitronyl Nitroxide Radical Incorporating Isophthalate Bridges  

Microsoft Academic Search

Two novel coordination polymers of formula [Zn(NIT4py)2(ip)]n (1) and [Cd(NIT4py)2(ip)(H2O)]n (2) (NIT4py=2-(4?-pyridinyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide and ip=isophthalate dianion), have been synthesized\\u000a and determined by X-ray diffraction. The crystal structures of the complexes are both neutral 1-D chains. The Zn(II) ion adopts\\u000a a distorted tetrahedral geometry and the Cd(II) ion adopts a distorted pentagonal bipyramidal geometry. Each isophthalate\\u000a dianion binds two metal ions in

Shu-Ping Wang; Dong-Zhao Gao; Dai-Zheng Liao; Zong-Hui Jiang; Shi-Ping Yan

2006-01-01

245

Gas detection by structural variations of fluorescent guest molecules in a flexible porous coordination polymer  

NASA Astrophysics Data System (ADS)

The development of a new methodology for visualizing and detecting gases is imperative for various applications. Here, we report a novel strategy in which gas molecules are detected by signals from a reporter guest that can read out a host structural transformation. A composite between a flexible porous coordination polymer and fluorescent reporter distyrylbenzene (DSB) selectively adsorbed CO2 over other atmospheric gases. This adsorption induced a host transformation, which was accompanied by conformational variations of the included DSB. This read-out process resulted in a critical change in DSB fluorescence at a specific threshold pressure. The composite shows different fluorescence responses to CO2 and acetylene, compounds that have similar physicochemical properties. Our system showed, for the first time, that fluorescent molecules can detect gases without any chemical interaction or energy transfer. The host-guest coupled transformations play a pivotal role in converting the gas adsorption events into detectable output signals.

Yanai, Nobuhiro; Kitayama, Koji; Hijikata, Yuh; Sato, Hiroshi; Matsuda, Ryotaro; Kubota, Yoshiki; Takata, Masaki; Mizuno, Motohiro; Uemura, Takashi; Kitagawa, Susumu

2011-10-01

246

Synthesis and characterization of two unsquare 4-connected 2D coordination polymers with helical character  

NASA Astrophysics Data System (ADS)

Under hydrothermal conditions, two 2D coordination polymers based on methylenediisophthalic acid (H4L) and 1,2-bis(imidazole-1-ylmethyl)benzene/1,3-bis(imidazole-1-ylmethyl)benzene (o-bix/m-bix) connectors were prepared and characterized by single crystal X-ray diffraction, IR and TG analysis. The structural analysis shows that complexes 1-2 have interesting unsquare 4-connected topological nets. Complex 1 has the Schläfli symbol (32.4.62.7)2(32.62.72) with the distorted ?-W net and complex 2 has the seldom reported Schläfli symbol (3.4.5.62.7)2(3.42.52.7). Moreover, there exist 1D helical chains [M2(bix)2]? (M = NiII and CoII) in 2D chiral layer of 1 and 2D nonchiral layer of 2.

Duan, Xian-Ying; Zhao, Jun-Hong; Wei, Mei-Lin

2014-01-01

247

Assembly of two novel Lindqvist polyoxoanion-templated coordination polymers with standard honeycomb cavities  

NASA Astrophysics Data System (ADS)

Two novel polyoxometalate(POM)-templated coordination polymers: [Cu 2(phnz) 3][M 6O 19] (M = Mo for 1, W for 2; phnz = phenazine), have been hydrothermally synthesized and characterized by routine physical methods and single crystal X-ray diffraction. In the compounds, Lindqvist POMs as templates induce the [Cu 2(phnz) 3] complexes to 2D hexagonal metal-organic framework (MOF), which represents 6 3 topologies of dimensions ca. 13.515 × 13.515 × 13.515 Å. Furthermore, the 2D sheets are held together by Lindqvist POMs into 3D supramolecular networks with 1D channel, and Lindqvist POMs site in the channels. The successful syntheses and isolation of two compounds provide a novel example of the utility of POM clusters as templates for self-assembly extended framework with cavities.

Sha, Jingquan; Huang, Lin; Peng, Jun; Pang, Haijun; Tian, Aixiang; Zhang, Pengpeng; Chen, Yuan; Zhu, Min

2009-02-01

248

A novel pseudo-2D structural motif in an anionic copper(II) dicyanamide coordination polymer.  

SciTech Connect

Anionic coordination polymers of divalent first-row transition elements are promising components of multifunctional molecular materials in which electronic conduction and magnetism can coexist. We report that a tetraphenylphosphonium salt containing a copper(II) dicyanamide anion has a novel pseudo-two-dimensional anionic structure and may provide a suitable electrolyte for the electrocrystallization of charge transfer salts. This (PPh{sub 4}){sub 3}Cu{sub 4}(dca){sub 11} salt crystallizes in the monoclinic space group P2{sub 1} with lattice parameters, a = 7.1911(4) {angstrom}, = 55.050(3) {angstrom}, c = 11.7964(7) {angstrom}, {beta} = 99.166(3){sup o} and V = 4610.2(7) {angstrom}{sup 3} at T = 298 K.

Schlueter, J. A.; Manson, J. L.; Geiser, U.; Materials Science Division; Eastern Washington Univ.

2007-01-01

249

Controlled crystallization of cyano-bridged cu-pt coordination polymers with two-dimensional morphology.  

PubMed

Two-dimensional (2D) coordination polymers (CPs) have a highly accessible surface area that permits guest molecules to effectively access the micropores in the CPs. Here we report a bottom-up synthesis of 2D cyano-bridged Cu-Pt CP nanoflakes using trisodium citrate as a chelating agent, which controls the nucleation rate and the crystal growth. The lateral sizes of the CP nanoflakes are controlled by changing the amount of trisodium citrate used. We strongly believe that our method will be useful for the preparation of other types of 2D CP nanoflakes. The 2D CPs have many active sites for catalytic and electrochemical reactions, and furthermore the assembled CPs can be used as membrane filters. PMID:24719297

Zakaria, Mohamed B; Hu, Ming; Tsujimoto, Yoshihiro; Sakka, Yoshio; Suzuki, Norihiro; Kamachi, Yuichiro; Imura, Masataka; Ishihara, Shinsuke; Ariga, Katsuhiko; Yamauchi, Yusuke

2014-06-01

250

Electrical conductivity and luminescence properties of two silver(I) coordination polymers with heterocyclic nitrogen ligands  

NASA Astrophysics Data System (ADS)

The synthesis and X-ray structural characterization of two novel silver(I) coordination polymers, [Ag(NO3)(quin)]n (1) and [Ag8(HL)2(H2O)4(mpyz)]·3H2O (2) are reported, where quin=5,6,7,8-tetrahydroquinoxaline, H6L=cyclohexane-1,2,3,4,5,6-hexacarboxylic acid and mpyz=2-methyl pyrazine. The single crystal diffraction analyses showed that complex 1 is a 2D layered structure, while 2 presents a 3D polymeric architecture. In complex 2 the network is stabilized by argentophilic interactions and hydrogen bonding. Electrical conductivity of order 3×10-4 Scm-1 (1) and 1.6×10-4 Scm-1 (2) is measured on thin film specimen at room temperature. The photoluminescence and thermal properties of the complexes have also been studied.

Rana, Abhinandan; Kumar Jana, Swapan; Pal, Tanusri; Puschmann, Horst; Zangrando, Ennio; Dalai, Sudipta

2014-08-01

251

A 3D chiral porous In(III) coordination polymer with PtS topological net.  

PubMed

The solvothermal reaction of In(III) and 1,2,4,5-benzeneteracarboxylic acid with the presence of piperazine leads to the generation of a novel 3D chiral porous coordination polymer with PtS topological net. Interestingly, the resulting crystals were not a racemic mixture but enantiomeric excess, which was confirmed by the measurement of optical rotation of bulk samples using solid vibrational circular dichroism (VCD) spectra and the solid circular dichroism (CD) spectra based on large crystals from one crystallization. High-pressure CO(2) and CH(4) adsorption measurement at 298 K reveals that activated 1 can absorb 45.8 cm(3) (STP)/g CO(2) at 22 atm and 22.5 cm(3) (STP)/g CH(4) at 25 atm. PMID:21822520

Han, Zheng-Bo; Li, Bi-Ye; Ji, Jian-Wei; Du, Yi-En; An, Hai-Yan; Zeng, Ming-Hua

2011-09-28

252

A novel copper(II) coordination polymer with carboxylate and isoindol backbones of a bifunctional ligand  

NASA Astrophysics Data System (ADS)

The reaction of a bifunctional ligand, 3-(1-oxo-1,3-dihydro-isoindol-2-yl)-propionic acid (Hpda) with Cu(NO3)2?3H2O in methanol-water in the presence of NaOH at room temperature produces a novel dinuclear copper(II) coordination polymer [Cu2(pda)4]n. The complex is fully characterized in the solid state as well as in solution using various analytical techniques including single crystal X-ray diffraction study. The single crystal X-ray structure analysis reveals that the monomeric unit of complex consists of Cu2(O2CR)4 paddlewheel building unit, where the two copper centers acquire a distorted square pyramidal geometry with amide oxygen of the isoindol ring of an adjacent Hpda ligand sitting on the axial positions.

Patra, Ayan; Sen, Tamal K.; Musie, Ghezai T.; Mandal, Swadhin K.; Bera, Manindranath

2013-09-01

253

Structural optimization of interpenetrated pillared-layer coordination polymers for ethylene/ethane separation.  

PubMed

With the goal of achieving effective ethylene/ethane separation, we evaluated the gas sorption properties of four pillared-layer-type porous coordination polymers with double interpenetration, [Zn2(tp)2(bpy)]n (1), [Zn2(fm)2(bpe)]n (2), [Zn2(fm)2(bpa)]n (3), and [Zn2(fm)2(bpy)]n (4) (tp = terephthalate, bpy = 4,4'-bipyridyl, fm = fumarate, bpe = 1,2-di(4-pyridyl)ethylene and bpa = 1,2-di(4-pyridyl)ethane). It was found that 4, which contains the narrowest pores of all of these compounds, exhibited ethylene-selective sorption profiles. The ethylene selectivity of 4 was estimated to be 4.6 at 298?K based on breakthrough experiments using ethylene/ethane gas mixtures. In addition, 4 exhibited a good regeneration ability compared with a conventional porous material. PMID:24692214

Kishida, Keisuke; Horike, Satoshi; Watanabe, Yoshihiro; Tahara, Mina; Inubushi, Yasutaka; Kitagawa, Susumu

2014-06-01

254

Lipid-Coated Nanoscale Coordination Polymers for Targeted Delivery of Antifolates to Cancer Cells  

PubMed Central

Nanoscale coordination polymers (NCPs) have been demonstrated as an interesting platform for drug delivery, as they possess many advantages over small-molecule chemotherapeutics, such as high payloads, lower systemic toxicity, tunability, and enhanced tumor uptake. Existing formulations for the delivery of methotrexate (MTX), an antifolate cancer drug, have very low drug loadings. Herein, we report the incorporation of MTX as a building block in an NCP formulation with exceptionally high drug loadings (up to 79.1 wt%) and the selective delivery of the NCP to cancer cells. Encapsulation of the NCP in a functionalized lipid bilayer allows for targeted delivery and controlled release to cancer cells. A phosphor can be doped into the NCPs for monitoring particle uptake by optical imaging. The lipid-coated and anisamide-targeted NCPs have superior in vitro efficacy against acute lymphoblastic leukemia cells when compared to free drug.

Huxford, Rachel C.; deKrafft, Kathryn E.; Boyle, William S.; Liu, Demin

2013-01-01

255

Flexible Two-Dimensional Square-Grid Coordination Polymers: Structures and Functions  

PubMed Central

Coordination polymers (CPs) or metal-organic frameworks (MOFs) have attracted considerable attention because of the tunable diversity of structures and functions. A 4,4?-bipyridine molecule, which is a simple, linear, exobidentate, and rigid ligand molecule, can construct two-dimensional (2D) square grid type CPs. Only the 2D-CPs with appropriate metal cations and counter anions exhibit flexibility and adsorb gas with a gate mechanism and these 2D-CPs are called elastic layer-structured metal-organic frameworks (ELMs). Such a unique property can make it possible to overcome the dilemma of strong adsorption and easy desorption, which is one of the ideal properties for practical adsorbents.

Kajiro, Hiroshi; Kondo, Atsushi; Kaneko, Katsumi; Kanoh, Hirofumi

2010-01-01

256

A 3D porous indium(III) coordination polymer involving in-situ ligand synthesis  

SciTech Connect

The hydrothermal reaction of In{sup 3+} and 1,2,4-benzenetricarboxylic acid with the presence of piperazine leads to the generation of a novel 3D porous coordination polymer, [H{sub 3}O][In{sub 2}(btc)(bdc)(OH){sub 2}].5.5H{sub 2}O (1), (btc=1,2,4-benzenetricarboxylate, bdc=1,4-benzenedicarboxylate). Compound 1 crystallizes in orthorhombic space group Pbca with a=16.216(7) A, b=13.437(6) A, c=31.277(14) A, and Z=8. It is interesting to find that the in-situ decarboxylation reaction of 1,2,4-benzenetricarboxylate (btc) partially transformed into 1,4-benzenedicarboxylate (bdc) occurs. The 16 indium(III) centers were linked by four btc, four bdc and two mu{sub 2}-OH ligands to form a box-girder. The adjacent box-girders are further connected by the bdc and btc ligands to generate a novel porous metal-organic framework containing nanotubular open channel with a cross-section of approximately 11.5x11.3 A{sup 2}. The micropores are occupied by lattice water molecules, and the solvent-accessible volume of the unit cell was estimated to be 3658.6 A{sup 3}, which is approximately 53.7% of the unit-cell volume (6815.4 A{sup 3}). - Graphical Abstract: The hydrothermal reaction of In{sup 3+} and 1,2,4-benzenetricarboxylic acid with the presence of piperazine leads to the generation of a novel 3D porous coordination polymer, [H{sub 3}O][In{sub 2}(btc)(bdc)(OH){sub 2}].5.5H{sub 2}O, (btc=1,2,4-benzenetricarboxylate, bdc=1,4-benzenedicarboxylate).

Han Zhengbo, E-mail: ceshzb@lnu.edu.c [College of Chemistry, Liaoning University, Shenyang 110036 (China); Song Yongjuan; Ji Jianwei; Zhang Wei; Han Guangxi [College of Chemistry, Liaoning University, Shenyang 110036 (China)

2009-11-15

257

Synthesis, crystal structures and properties of a series of three-dimensional lanthanide coordination polymers with the rigid and flexible mixed dicarboxylate ligands of 1,4-benzene dicarboxylic acid and succinic acid  

NASA Astrophysics Data System (ADS)

A series of new lanthanide coordination polymers, with the formula [Ln(Suc) 0.5( p-BDC)] (Ln = Eu ( 1), Sm ( 2), Tb ( 3), Pr ( 4), Ho ( 5); H 2Suc = succinic acid; p-H 2BDC = 1,4-benzene dicarboxylic acid), have been synthesized under hydrothermal condition and all of them have been structurally characterized. X-ray diffraction analyses reveal that complexes 1- 5 are isostructural and crystallized in orthorhombic space group Pbca. One-dimensional infinite inorganic edge-sharing polyhedra chains formed by lanthanide ions and tetradentate carboxyl groups of succinic acid ligands, link to each other through the carbon atoms of succinic acid ligands and phenyl groups of the 1,4-benzene dicarboxylic acid ligands, to lead to a three-dimensional framework structure. In addition, the phase purities of the bulk samples were identified by X-ray powder diffraction. The photoluminescent properties of 1 and 3 were discussed in detail.

Wang, Chun-Guang; Xing, Yong-Heng; Li, Zhang-Peng; Li, Jing; Zeng, Xiao-Qing; Ge, Mao-Fa; Niu, Shu-Yun

2009-03-01

258

Mechanism of ultrasound scission of a silver-carbene coordination polymer.  

PubMed

Scission of a supramolecular polymer-metal complex can be carried out using collapsing cavitation bubbles created by ultrasound. Although the most plausible scission mechanism of the coordinative bonds is through mechanical force, the influence of radicals and high hot-spot temperatures on scission has to be considered. A silver(I)-N-heterocyclic carbene complex was exposed to 20 kHz ultrasound in argon, nitrogen, methane, and isobutane saturated toluene. Scission percentages were almost equal under argon, nitrogen, and methane. Radical production differs by a factor of 10 under these gases, indicating that radical production is not a significant contributor to the scission process. A model to describe the displacement of the bubble wall, strain rates, and temperature in the gas shows that critical strain rates for coil-to-stretch transition, needed for scission, are achieved at reactor temperatures of 298 K, an acoustic pressure of 1.2 × 10(5) Pa, and an acoustic frequency of 20 kHz. Lower scission percentages were measured under isobutane, which also shows lower strain rates in model simulations. The activation of the polymer-metal complexes in toluene under the influence of ultrasound occurs through mechanical force. PMID:21827184

Rooze, Joost; Groote, Ramon; Jakobs, Robert T M; Sijbesma, Rint P; van Iersel, Maikel M; Rebrov, Evgeny V; Schouten, Jaap C; Keurentjes, Jos T F

2011-09-29

259

Suppression of realgar cage degradation during complexation: formation of hybrid coordination polymers with As4S4, PAs3S3, and Cu(I) halide building blocks.  

PubMed

Realgar, As(4)S(4), reacts with Cr(CO)(5)THF under cage degradation to give As(4)S(3)·Cr(CO)(5) (1). The reverse structural change is found if solutions of 1 in CH(2)Cl(2) react with equimolar amounts of PAs(3)S(3)·W(CO)(5) and CuX (X = Cl, Br, I) in CH(3)CN under biphasic diffusion conditions. The resulting coordination polymers 2-4 contain a reconstituted realgar molecule along with the PAs(3)S(3) cage. The crystal structures of (CuX)(As(4)S(4))(PAs(3)S(3)) (X = Cl: 2; Br: 3) are characterized by one-dimensional (1D) (CuX)(As(4)S(4)) strands, which are formed by alternating As(4)S(4) cages and CuX dumbbells. Terminal PAs(3)S(3) molecules are coordinated to copper by apical phosphorus and bridging realgar through sulfur. The As(3) triangles of the resulting (CuX)(As(4)S(4))(PAs(3)S(3)) strands interact with halides of neighbored strands to give a folded three-dimensional (3D) network. The structure of (CuI)(3)(As(4)S(4))(PAs(3)S(3)) (4) contains 1D (Cu(3)I(3))(n) strands as backbones, which are bridged by sulfur atoms of two ?(1:2)-As(4)S(4) molecules while PAs(3)S(3) confines the resulting sheet. The As(3) triangles at the surface of the layers interact with iodide of the next layer to form a layered 3D network. PMID:22074415

Schwarz, Patrick; Wachter, Joachim; Zabel, Manfred

2011-12-19

260

Copper(I) thiocyanate coordination polymers with dimethylpyrazine: synthesis, crystal structures, thermal and luminescence properties  

NASA Astrophysics Data System (ADS)

The new copper(I) coordination polymers poly[(di- ?2-thiocyanato- N, S)-( ?2-2,5-dimethylpyrazine- N, N)] dicopper(I) ( I) and poly[di- ?2-thiocyanato- N, S)-( ?2-2,3-dimethyl-pyrazine- N, N)] dicopper(I) ( II) were prepared by the reaction of copper(I) thiocyanate with 2,3- and 2,5-dimethylpyrazine in acetonitrile. In all compounds different CuSCN sub-structures are found which are connected by the dimethylpyrazine ligands to multi-dimensional coordination networks. The thermal properties of all compounds were investigated using simultaneous differential thermoanalysis (DTA), thermogravimetry (TG) and mass spectrometry (MS) as well as temperature resolved X-ray powder diffraction. On heating, compound I and II loose all of the dimethylpyrazine ligands in an endothermic reaction and transform directly into copper(I) thiocyanate. Optical investigations show two excited states for both compounds in absorption and in luminescence measurements which are both, MC and LMCT in character.

Näther, Christian; Greve, Jan; Jeß, Inke; Wickleder, Claudia

2003-08-01

261

Spinons, Solitons, and Breathers in Quasi-One-Dimensional Magnets  

NASA Astrophysics Data System (ADS)

By scattering neutrons from coordination polymer magnets, we contrast the effects of a uniform and a staggered magnetic field on the quantum critical state of a spin-1/2 chain. In a partially magnetized state of copper pyrazine dinitrate (CuPzN) we find bounded spectral continua indicating that neutrons scatter from spin-1/2 quasi-particle pairs [1]. The complex boundaries including an incommensurate soft spot result from a field induced shift in the Fermi points for these quasi-particles. The measurements indicate that the magnetized state of CuPzN remains quantum critical. Copper benzoate [2] and CuCl2^.2(dimethylsulfoxide) (CDC) [3] differ from CuPzN in that there are two spins per unit cell along the spin chain. Rather than continuous spectra, we find resolution limited gapped excitations when these materials are subject to high fields. So with two spins per unit cell, an applied field can drive the spin-1/2 chain away from criticality. The explanation for this effect was provided by Affleck and Oshikawa. The alternating coordination environment induces a transverse staggered field and spinon binding. The quantum sine-Gordon model is the relevant low energy field theory and it predicts soliton and breather excitations at specific energies and wave vectors that we compare to the experiments. We shall also compare a complete measurement of the dynamic spin correlation function for CDC in a field to exact diagonalization results for a spin-1/2 chain with a staggered and uniform magnetic field [4]. [1] M. B. Stone, D. H. Reich, C. Broholm, K. Lefmann, C. Rischel, C. P. Landee, and M. M. Turnbull, Phys. Rev. Lett. 91, 037205 (2003). [2] M. Kenzelmann, Y. Chien, C. Broholm, D. H. Reich, and Y. Qiu, Phys. Rev. Lett. 93, 017204 (2004). [3] D. C. Dender, P. R. Hammar, Daniel H. Reich, C. Broholm, and G. Aeppli, Phys. Rev. Lett. 79, 1750 (1997). [4] M. Kenzelmann, C. D. Batista, Y. Chen, C. Broholm, D. H. Reich, S. Park, and Y. Qiu, Phys. Rev. B 71, 094411 (2005).

Broholm, Collin

2006-03-01

262

Probing exchange pathways in one-dimensional aggregates with super-resolution microscopy.  

PubMed

Supramolecular fibers are prominent structures in biology and chemistry. A quantitative understanding of molecular exchange pathways in these one-dimensional aggregates was obtained by a combination of super-resolution stochastic optical reconstruction microscopy and stochastic simulation. The potential of this methodology is demonstrated with a set of well-defined synthetic building blocks that self-assemble into supramolecular fibrils. Previous ensemble measurements hid all molecular phenomena underpinning monomer exchange, but the molecular pathway determined from single-aggregate studies revealed unexpected homogeneous exchange along the polymer backbone. These results pave the way for experimental investigation of the structure and exchange pathways of synthetic and natural supramolecular fibers. PMID:24786073

Albertazzi, Lorenzo; van der Zwaag, Daan; Leenders, Christianus M A; Fitzner, Robert; van der Hofstad, Remco W; Meijer, E W

2014-05-01

263

The One-Dimensional Approximation for Infiltration in Heterogeneous Soils  

NASA Astrophysics Data System (ADS)

Appendix is available with entire article on microfiche. Order from American Geophysical Union, 2000 Florida Avenue, N.W., Washington, DC 20009. Document W91-004; $2.50. Payment must accompany order. By using analytical solutions to the problem of one- and two-dimensional linearized unsteady infiltration from a strip source in a soil with saturated hydraulic conductivity varying exponentially in space, explicit criteria for the validity of the one-dimensional approximation are derived, in terms of parameters describing the soil type, the uniformity of the infiltrating source at the surface, and the soil heterogeneity. Numerical solutions for the linearized infiltration problem are developed for any variation of hydraulic conductivity in space. Extensive simulations suggest that for a sizable strip source and moderate variation of hydraulic conductivity, a set of independent neighboring soil columns represents well the multidimensional infiltration problem. The possibility of defining sufficient parameters controlling the accuracy of the one-dimensional approximation is discussed.

Protopapas, Angelos L.; Bras, Rafael L.

1991-06-01

264

Extended acoustic waves in a one-dimensional aperiodic system  

NASA Astrophysics Data System (ADS)

We numerically study the propagation of acoustic waves in a one-dimensional system with an aperiodic pseudo-random elasticity distribution. The elasticity distribution was generated by using a sinusoidal function whose phase varies as a power-law, ? ? n^{?}, where n labels the positions along the media. By considering a discrete one-dimensional version of the wave equation and a matrix recursive reformulation we compute the localization length within the band of allowed frequencies. In addition, we apply a second-order finite-difference method for both the time and spatial variables and study the nature of the waves that propagate in the chain. Our numerical data indicates the presence of extended acoustic waves with non-zero frequency for sufficient degree of aperiodicity.

Costa, A. E. B.; de Moura, F. A. B. F.

2011-02-01

265

The various architectures and properties of a series of coordination polymers tuned by the central metals.  

PubMed

Five new metal-organic coordination polymers based on the mixed ligands of a semi-rigid bis-pyridyl-bis-amide N,N'-bis(3-pyridinecarboxamide)-1,2-cyclohexane (3-bpah) and 1,4-benzenedicarboxylic acid (1,4-H2BDC), namely [Co(3-bpah)(1,4-BDC)(H2O)3] (1), [Ni(3-bpah)(1,4-BDC)(H2O)3] (2), [Cu(3-bpah)(1,4-BDC)] (3), [Zn(3-bpah)(1,4-BDC)]·H2O (4) and [Cd(3-bpah)(1,4-BDC)(H2O)] (5), have been hydrothermally synthesized and structurally characterized. Complexes 1 and 2 are isostructural and display the similar 1D infinite chains, which are further linked via hydrogen-bonding interactions to generate 3D supramolecular frameworks. Complex 3 features a 3D polymeric framework with CdSO4-like topology. Complexes 4 and 5 show two similar 2D (2,4)-connected networks with (4·8(5))(4) topology, in which the 3-bpah ligands adopt different ?2-bridging coordination modes via the ligation of two pyridyl nitrogen atoms in 4 and via the ligation of one pyridyl nitrogen and one amide oxygen atom in 5. In addition, the central metals show different coordination geometries in 4 and 5. The adjacent layers of complexes 4 and 5 are finally extended into 3D supramolecular architectures through hydrogen-bonding interactions. The effects of the central metals on the structures and properties of complexes 1-5 have been discussed. The electrochemical properties of complexes 1-3 and fluorescent sensing behaviors of 4-5 toward ethanol and nitrobenzene have been investigated in detail. PMID:24723145

Wang, Xiu-Li; Luan, Jian; Lin, Hong-Yan; Le, Mao; Liu, Guo-Cheng

2014-06-01

266

Cold Dipolar Gases in Quasi-One-Dimensional Geometries  

SciTech Connect

We analyze the physics of cold dipolar gases in quasi-one-dimensional geometries, showing that the confinement-induced scattering resonances produced by the transversal trapping are crucially affected by the dipole-dipole interaction. As a consequence, the dipolar interaction may drastically change the properties of quasi-1D dipolar condensates, even for situations in which the dipolar interaction would be completely overwhelmed by the short-range interactions in a 3D environment.

Sinha, S. [S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Kolkata 700098 (India); Santos, L. [Institut fuer Theoretische Physik, Leibniz Universitaet Hannover, Appelstr. 2, D-30167 Hannover (Germany)

2007-10-05

267

One-dimensional growth mechanism of amorphous boron nanowires  

Microsoft Academic Search

High-density of arrays of self-oriented boron nanowires grown on silicon substrates were synthesized by radio-frequency magnetron sputtering with a target of highly pure boron and boron oxide mixture using argon as the sputtering atmosphere. TEM studies show that the conventional growth mechanisms such as Frank screw-dislocation mechanism and the vapor–liquid–solid mechanisms are not suitable for the one-dimensional growth of boron

Y. Q. Wang; X. F. Duan; L. M. Cao; W. K. Wang

2002-01-01

268

Quasi-one-dimensional magnons in an intermetallic marcasite  

SciTech Connect

We present inelastic neutron scattering measurements and rst principles calculations examining the intermetallic marcasite CrSb2. The observed spin wave dispersion implies that the magnetic interactions are strongly one-dimensional with antiferromagnetic chains parallel to the crystalline c-axis. Such low-dimensional excitations are unexpected in a semiconducting intermetallic system. Moreover this material may be further interesting in that the magnetic anisotropy may enhance thermoelectric properties along particular crystallographic directions.

Stone, Matthew B [ORNL; Lumsden, Mark D [ORNL; Nagler, Stephen E [ORNL; Singh, David J [ORNL; Sales, Brian C [ORNL; Mandrus, David [ORNL

2012-01-01

269

Cosolvent-Water Displacement in One-Dimensional Soil Column  

Microsoft Academic Search

A one-dimensional flow and transport model with dynamic fluid density and viscosity terms is proposed for modeling cosolvent flushing in a water-saturated porous medium. Given knowledge of the density and viscosity functions for cosolvent-water mixtures, the model is controlled by two flow parameters (specific storage and permeability) and one transport parameter (dispersivity). Sensitivity analysis demonstrates that the model solution is

Thomas C. Harmon; Tae-Joon Kim; Brian K. Dela Barre; Constantinos V. Chrysikopoulos

1999-01-01

270

Thermalization in a one-dimensional integrable system  

SciTech Connect

We present numerical results demonstrating the possibility of thermalization of single-particle observables in a one-dimensional system, which is integrable in both the quantum and classical (mean-field) descriptions (a quasicondensate of ultracold, weakly interacting bosonic atoms are studied as a definite example). We find that certain initial conditions admit the relaxation of single-particle observables to the equilibrium state reasonably close to that corresponding to the Bose-Einstein thermal distribution of Bogoliubov quasiparticles.

Grisins, Pjotrs [Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, A-1020 Vienna (Austria); Mazets, Igor E. [Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, A-1020 Vienna (Austria); Ioffe Physico-Technical Institute, 194021 St. Petersburg (Russian Federation)

2011-11-15

271

Many-body Anderson localization in one-dimensional systems  

NASA Astrophysics Data System (ADS)

We show, using quasi-exact numerical simulations, that Anderson localization in a disordered one-dimensional potential survives in the presence of attractive interaction between particles. The localization length of the particles' center of mass—computed analytically for weak disorder—is in good agreement with the quasi-exact numerical observations using the time evolving block decimation algorithm. Our approach allows for simulation of the entire experiment including the final measurement of all atom positions.

Delande, Dominique; Sacha, Krzysztof; P?odzie?, Marcin; Avazbaev, Sanat K.; Zakrzewski, Jakub

2013-04-01

272

Radiation from one-dimensional dielectric leaky-wave antennas  

Microsoft Academic Search

Dielectric leaky-wave antennas consist of multiple dielectric layers above a ground plane, along with a simple source such as an infinite line current in the one-dimensional case. The layers act as a guiding structure for one or more leaky waves, which are responsible for producing a narrow-beam radiation pattern. Depending on the beam angle, the leaky waves may extend for

Helmut Ostner; J. Detlerfsen; David R. Jackson

1995-01-01

273

Effective Bragg conditions in a one-dimensional quasicrystal.  

PubMed

We present occurrence of the effective Bragg conditions with wide gapwidth and high reflectance in a Fibonacci superlattice, which is a typical one-dimensional quasicrystal. In the Fibonacci material, the number of effective Bragg conditions is two rather than one which appears in traditional periodic structures. Based on the effective Bragg conditions, this study proposes existence of omnidirectional, wideband and high reflectance in the quasiperiodic materials analogous to that in traditional materials. PMID:23187516

Hsueh, W J; Chang, C H; Cheng, Y H; Wun, S J

2012-11-19

274

Alpha-Continuity Properties of One-Dimensional Quasicrystals  

Microsoft Academic Search

We apply the Jitomirskaya-Last extension of the Gilbert-Pearson theory to discrete one-dimensionalSchrodinger operators with potentials arising from generalized Fibonacci sequences. We prove for certainrotation numbers that for every value of the coup ling constant, there exists an ff ? 0 such that thecorresponding operator has purely ff-continuous spectrum. This result follows from uniform upper andlower bounds for the k \\\\Delta

David Damanik

1997-01-01

275

The Cauchy Problem for a One Dimensional Nonlinear Peridynamic Model  

Microsoft Academic Search

This paper studies the Cauchy problem for a one-dimensional nonlinear peridynamic model describing the dynamic response of an infinitely long elastic bar. The issues of local well-posedness and smoothness of the solutions are discussed. The existence of a global solution is proved first in the sublinear case and then for nonlinearities of degree at most three. The conditions for finite-time

H. A. Erbay; A. Erkip; G. M. Muslu

2010-01-01

276

Image processing using one-dimensional processor arrays  

Microsoft Academic Search

The first half of this paper presents the design rationale for CNAPS, a specialized one-dimensional (1-D) processor array developed by Adaptive Solutions Inc. In this context, we discuss the problem of Amdahl's law which severely constrains special-purpose architectures. We also discuss specific architectural decisions such as the kind of parallelism, the computational precision of the processors, on-chip versus off-chip processor

DAN W. HAMMERSTROM; DANIEL P. LULICH

1996-01-01

277

Growth of one-dimensional single-crystalline hydroxyapatite nanorods  

NASA Astrophysics Data System (ADS)

A facile, effective and template/surfactant-free hydrothermal route in the presence of sodium bicarbonate was developed to synthesize highly uniform single-crystalline hydroxyapatite (HA) nanorods with the lengths of several hundred nanometers and aspect ratio up to ˜20. One dimensional (1-D) growth and aspect ratio could be controlled by hydrothermal reaction time and temperature. The longitudinal axis, also the growth direction of the nanorods, is parallel to the [001] direction of HA hexagonal crystal structure.

Ren, Fuzeng; Ding, Yonghui; Ge, Xiang; Lu, Xiong; Wang, Kefeng; Leng, Yang

2012-06-01

278

One-Dimensional Quantum Walks with One Defect  

NASA Astrophysics Data System (ADS)

The CGMV method allows for the general discussion of localization properties for the states of a one-dimensional quantum walk, both in the case of the integers and in the case of the nonnegative integers. Using this method we classify, according to such localization properties, all the quantum walks with one defect at the origin, providing explicit expressions for the asymptotic return probabilities to the origin.

Cantero, M. J.; Grünbaum, F. A.; Moral, L.; Velázquez, L.

279

Anyons in one-dimensional lattices: a photonic realization.  

PubMed

Anyons are nonlocal quasi-particles carrying fractional statistics that interpolate between bosons and fermions. Here we propose a photonic realization of anyons moving on a one-dimensional lattice, which is based on light transport in an engineered square array of optical waveguides with a helically bent axis. Our photonic simulator enables visualization of the nonlocal nature of anyons in Fock space and the persistence of correlated tunneling even in the absence of particle interaction. PMID:22660154

Longhi, Stefano; Della Valle, Giuseppe

2012-06-01

280

Quantum Phase Transition in the One-Dimensional XZ Model  

Microsoft Academic Search

We introduce a one-dimensional (1D) XZ model with alternating $\\\\sigma_i^z\\\\sigma_{i+1}^z$ and $\\\\sigma_i^x\\\\sigma_{i+1}^x$ interactions on even\\/odd bonds, interpolating between the Ising model and the quantum compass model. We present two ways of its exact solution by: ($i$) mapping to the quantum Ising models, and ($ii$) using fermions with spin 1\\/2. In certain cases the nearest neighbor pseudospin correlations change discontinuously at

Wojciech Brzezicki; Andrzej M. Oles

2008-01-01

281

Quantum phase transition in the one-dimensional compass model  

Microsoft Academic Search

We introduce a one-dimensional model which interpolates between the Ising model and the quantum compass model with frustrated pseudospin interactions sigmaizsigmai+1z and sigmaixsigmai+1x , alternating between even and\\/or odd bonds, and present its exact solution by mapping to quantum Ising models. We show that the nearest-neighbor pseudospin correlations change discontinuously and indicate divergent correlation length at the first-order quantum phase

Wojciech Brzezicki; Jacek Dziarmaga; Andrzej M. Oles

2007-01-01

282

On the Theory of Superconductivity: The One-Dimensional Case  

Microsoft Academic Search

The one-dimensional case of free electrons interacting with lattice displacements is solved by a self-consistent method. It is found that for a certain range of the interaction parameter a single sinusoidal lattice displacement is strongly excited in the lowest level of the system. Its wave-length is such as to create an energy gap in the single-electron energy spectrum with all

H. Frohlich

1954-01-01

283

Super-crystalline phase in quasi-one-dimensional conductors  

NASA Astrophysics Data System (ADS)

A model, where phase transition between the Peierls and periodic soliton wall superlattice (super-crystalline) charge-density-wave phases occur in a magnetic field, is proposed. The model accounts for the peculiarities of the phase diagram in a quasi-one-dimensional conductor (Per)2Pt(mnt)2. In the absence of a magnetic field, our model is equivalent to the exactly solvable model of Brazovskii, Dzyaloshinskii, and Kirova.

Lebed, A. G.; Wu, S.

2009-03-01

284

Threshold singularities in the one-dimensional Hubbard model  

NASA Astrophysics Data System (ADS)

We consider excitations with the quantum numbers of a hole in the one-dimensional Hubbard model below half-filling. We calculate the finite-size corrections to the energy. The results are then used to determine threshold singularities in the single-particle Green’s function for commensurate fillings. We present the analogous results for the Yang-Gaudin model (electron gas with ? -function interactions).

Essler, Fabian H. L.

2010-05-01

285

Cryptography using multiple one-dimensional chaotic maps  

NASA Astrophysics Data System (ADS)

Recently, Pareek et al. [Phys. Lett. A 309 (2003) 75] have developed a symmetric key block cipher algorithm using a one-dimensional chaotic map. In this paper, we propose a symmetric key block cipher algorithm in which multiple one-dimensional chaotic maps are used instead of a one-dimensional chaotic map. However, we also use an external secret key of variable length (maximum 128-bits) as used by Pareek et al. In the present cryptosystem, plaintext is divided into groups of variable length (i.e. number of blocks in each group is different) and these are encrypted sequentially by using randomly chosen chaotic map from a set of chaotic maps. For block-by-block encryption of variable length group, number of iterations and initial condition for the chaotic maps depend on the randomly chosen session key and encryption of previous block of plaintext, respectively. The whole process of encryption/decryption is governed by two dynamic tables, which are updated time to time during the encryption/decryption process. Simulation results show that the proposed cryptosystem requires less time to encrypt the plaintext as compared to the existing chaotic cryptosystems and further produces the ciphertext having flat distribution of same size as the plaintext.

Pareek, N. K.; Patidar, Vinod; Sud, K. K.

2005-10-01

286

Novel one-dimensional polymeric chlorocadmate sulfonium salts obtained from sulfonium ylides: Synthesis and structural characterization  

NASA Astrophysics Data System (ADS)

Protonated sulfonium ylide chlorocadmate compounds of type [(Me)2SCHC(O)CHR]+[CdCl]-(R = H(1); p-Br (2); p-Me (3); p-OMe (4); p-NO2 (5)) were prepared by the reaction of ?-keto stabilized sulfonium ylides (Me)2SCHC(O)C6H4R with CdCl2?H2O in 1:2 M ratios using methanol as solvent. Characterization of the compounds by IR, 1H- and 13C NMR spectroscopy indicated the absence of coordination of the protonated sulfonium ylide to the metal through either the carbon or oxygen atoms. The crystal structures of compounds 1 and 2 were both found to consist of organic cations, [(Me)2SCHC(O)CHR]+(R = H(1) and p-Br (2)) and infinite one-dimensional chains of formula [CdCl]n- In both structures each Cd atom is five-coordinate with square pyramidal coordination geometry.

Sabounchei, Seyyed Javad; Bagherjeri, Fateme Akhlaghi; Boskovic, Colette; Gable, Robert W.

2013-08-01

287

Ultrasound-driven preparation and pair distribution function-assisted structure solution of a copper-based layered coordination polymer.  

PubMed

Nanoparticles of a copper-based layered coordination polymer, STAM-2, have been prepared via an ultrasound mediated transformation from a layered metal-organic framework, STAM-1. The structure of the material was then solved using pair distribution function analysis to identify the structural units present and the final structural model refined against the pair distribution function data. PMID:24310447

Mohideen, M Infas; Allan, Phoebe K; Chapman, Karena W; Hriljac, Joseph A; Morris, Russell E

2014-07-21

288

Thallium I phenylsuccinic acid coordination polymer as precursor for preparation of thallium (III) oxide nano structures by direct thermal decomposition  

NASA Astrophysics Data System (ADS)

A new thallium (I) coordination polymer [Tl(PsucH)] n (PsucH = phenylsuccinic acid) has been synthesized and characterized by single crystal X-Ray analysis, elemental analysis and IR spectroscopy. The single crystal X-Ray analysis shows that this polymer is 2-D along a axis. Flower-like nanostructure thallium (III) oxide, Tl2O3 has been prepared by direct thermal decomposition of thallium (I) coordination polymer. The nanostructure was characterized by scanning electron microscopy (SEM), X-Ray powder diffraction (XRD) and IR spectroscopy. The thermal stability of the Tl2O3 nanostructure was studied by thermal gravimetric analysis and differential thermal analysis (TGA /DTA) too.

Fard, Mohammad Jaafar Soltanian; Tabaroki, Sara

2014-01-01

289

Complementary in situ reactivity of isomeric dipyridylamide precursors and its effect on dimensionality of cadmium 5-nitroisophthalate coordination polymers  

NASA Astrophysics Data System (ADS)

Hydrothermal treatment of cadmium nitrate, 5-nitroisophthalic acid (H2nip) and one of two isomeric dipyridylamides resulted in coordination polymer crystalline solids that manifested different in situ reactivity and dimensionality, as ascertained by single crystal X-ray diffraction. Hydrolysis of 3-pyridylisonicotinamide (3-pina) afforded the 3-aminopyridine (3-ampyr) ligands observed in the 1-D ladder polymer {[Cd(nip)(3-ampyr)(H2O)]?2H2O}n (1). Conversely, hydrolysis of the isomeric precursor 3-pyridylnicotinamide (3-pna) generated the monoanionic nicotinate ligands in the 2-D coordination polymer [Cd2(nip)(nic)2(H2O)2]n (2). Compound 2 displays {Cd2(OCO)2} eight-membered ring dimeric units linked into (6,3) graphite-type slab motifs. Luminescent properties of these two new materials are also presented.

O'Donovan, Megan E.; LaDuca, Robert L.

2014-07-01

290

Alfvén wave propagation and ion cyclotron interactions in the expanding solar wind: One-dimensional hybrid simulations  

Microsoft Academic Search

We carry out one-dimensional hybrid simulations of Alfvn waves propagating along the magnetic field in the presence of a mean radial spherically expanding plasma outflow, representing fast solar wind streams. The equations for particle ions of multiple species and fluid electrons are solved using the Expanding Box Model, a locally Cartesian representation of motion in spherical coordinates, in a frame

Paulett C. Liewer; Marco Velli; Bruce E. Goldstein

2001-01-01

291

A one-dimensional collisional model for plasma-immersion ion implantation  

SciTech Connect

Plasma-immersion ion implantation (also known as plasma-source ion implantation) is a process in which a target is immersed in a plasma and a series of large negative-voltage pulses are applied to it to extract ions from the plasma and implant them into the target. A general one-dimensional model is developed to study this process in different coordinate systems for the case in which the pressure of the neutral gas is large enough that the ion motion in the sheath can be assumed to be highly collisional.

Vahedi, V.; Lieberman, M.A.; Alves, M.V.; Verboncoeur, J.P.; Birdsall, C.K. (Plasma Theory and Simulation Group, University of California, Berkeley, California 94720 (US))

1991-02-15

292

Exact particle and kinetic-energy densities for one-dimensional confined gases of noninteracting fermions.  

PubMed

We propose a new method for the evaluation of the particle density and kinetic pressure profiles in inhomogeneous one-dimensional systems of noninteracting fermions, and apply it to harmonically confined systems of up to N = 1000 fermions. The method invokes a Green's function operator in coordinate space, which is handled by techniques originally developed for the calculation of the density of single-particle states from Green's functions in the energy domain. In contrast to the Thomas-Fermi approximation, the exact profiles show negative local pressure in the tails and a prominent shell structure which may become accessible to observation in magnetically trapped gases of fermionic alkali atoms. PMID:11005951

Vignolo, P; Minguzzi, A; Tosi, M P

2000-10-01

293

One-dimensional plate impact experiments on the cyclotetramethylene tetranitramine (HMX) based explosive EDC32  

NASA Astrophysics Data System (ADS)

Eight one-dimensional plate impact experiments have been performed to study both the Shock to Detonation Transition and Hugoniot state in the cyclotetramethylene tetranitramine (HMX) based explosive EDC32. The experiments covered shock pressures ranging from 0.59 to 7.5 GPa with sustained shocks, double shocks, and short pulse shocks. Experiments were instrumented with embedded magnetic particle velocity gauges. Results include; (1) wave profiles of particle velocity vs. time vs. depth in the explosive, (2) time-distance coordinates for onset of detonation vs. initial shock pressure (aka the Pop-plot), (3) a reactants Hugoniot, and (4) measurement of the Hugoniot Elastic Limit of 0.22.GPa.

Burns, Malcolm J.; Gustavsen, Richard L.; Bartram, Brian D.

2012-09-01

294

Syntheses, structures and luminescence properties of lanthanide coordination polymers with helical character  

SciTech Connect

A series of lanthanide coordination polymers, (Him){sub n}[Ln(ip){sub 2}(H{sub 2}O)]{sub n} [Ln=La(1), Pr(2), Nd(3) and Dy(4), H{sub 2}ip=isophthalic acid, im=imidazole] and [Y{sub 2}(ip){sub 3}(H{sub 2}O){sub 2}]{sub n}.nH{sub 2}O (5), have been synthesized and characterized by elemental analyses, infrared (IR), ultraviolet-visible-near infrared (UV-Vis-NIR) and single-crystal X-ray diffraction analyses. The isostructural compounds 1-4 possess 3-D structures with three different kinds of channels. Compound 5 features a 2-D network making of two different kinds of quadruple-helical chains. Compounds 2 and 3 present the characteristic emissions of Pr(III) and Nd(III) ions in NIR region, respectively. Compound 4 shows sensitized luminescence of Dy(III) ions in visible region. - Graphical abstract: A series of lanthanide coodination polymers, (Him){sub n}[Ln(ip){sub 2}(H{sub 2}O)]{sub n} [Ln=La(1), Pr(2), Nd(3) and Dy(4)] and [Y{sub 2}(ip){sub 3}(H{sub 2}O){sub 2}]{sub n}.nH{sub 2}O (5), have been reported. The isostructural compounds 1-4 possess 3-D structures with three different kinds of channels. Compound 5 displays a 2-D network making of two kinds of quadruple-helical chains. Display Omitted.

Zhou Ruisha; Cui Xiaobing; Song Jiangfeng; Xu Xiaoyu [College of Chemistry and State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun, Jilin 130021 (China); Xu Jiqing [College of Chemistry and State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun, Jilin 130021 (China)], E-mail: xjq@mail.jlu.edu.cn; Wang Tiegang [College of Chemistry and State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun, Jilin 130021 (China)

2008-08-15

295

One-Dimensional Scanning Approach to Shock Sensing  

NASA Technical Reports Server (NTRS)

Measurement tools for high speed air flow are sought both in industry and academia. Particular interest is shown in air flows that exhibit aerodynamic shocks. Shocks are accompanied by sudden changes in density, pressure, and temperature. Optical detection and characterization of such shocks can be difficult because the medium is normally transparent air. A variety of techniques to analyze these flows are available, but they often require large windows and optical components as in the case of Schlieren measurements and/or large operating powers which precludes their use for in-flight monitoring and applications. The one-dimensional scanning approach in this work is a compact low power technique that can be used to non-intrusively detect shocks. The shock is detected by analyzing the optical pattern generated by a small diameter laser beam as it passes through the shock. The optical properties of a shock result in diffraction and spreading of the beam as well as interference fringes. To investigate the feasibility of this technique a shock is simulated by a 426 m diameter optical fiber. Analysis of results revealed a direct correlation between the optical fiber or shock location and the beam s diffraction pattern. A plot of the width of the diffraction pattern vs. optical fiber location reveals that the width of the diffraction pattern was maximized when the laser beam is directed at the center of the optical fiber. This work indicates that the one-dimensional scanning approach may be able to determine the location of an actual shock. Near and far field effects associated with a small diameter laser beam striking an optical fiber used as a simulated shock are investigated allowing a proper one-dimensional scanning beam technique.

Tokars, Roger; Adamovsky, Girgory; Floyd, Bertram

2009-01-01

296

Investigation on one-dimensional physics by NMR  

SciTech Connect

Proton pulsed NMR on three complementary one-dimensional systems, Cu(pc), Ni(pc)I, and Cu(pc)I is reported. Each of these exhibits different electronic behavior: localized electrons (spin 12) of Cu(pc), free electrons in the case of Ni(Pc)I, and a coexisting system of localized electrons and free electrons in Cu(pc)I. The spin-spin relaxation times for these materials are well explained at high temperature by the second moment of the proton dipole-dipole interaction, 20 ..mu..S, and at low temperature a demagnetization effect. Measurements of the proton spin-lattice relaxation rate, T/sub 1//sup -1/, reveal that the organic insulator Cu(pc) is a highly one-dimensional spin- 12 Heisenberg system with absolute value JK/sub B/ = 0.29 K and absolute value JJ' > 6 x 10/sup 3/, where J and J' are the intrachain and interchain exchange interactions. The energy band structure of the highly one-dimensional conductor Ni(pc)I appears to change at 60 K. NMR spin-lattice relaxation-rate measurements reveal that the conduction electron density is low at the positions of protons attached to the outside carbons of the pc ring. NMR and EPR data suggest that in Cu(pc)I the indirect exchange interaction mediated by conduction electrons, 6 K, is an order of magnitude stronger than that of the direct exchange interaction between Cu/sup +2/ local moments, 0.34 K.

Lee, S.

1987-01-01

297

An encapsulated helical one-dimensional cobalt iodide nanostructure  

NASA Astrophysics Data System (ADS)

Single-walled carbon nanotubes (SWNTs) can be used as templates for the growth of low-dimensional inorganic materials whose structures and properties often differ greatly from those of the bulk. Here we describe the detailed crystallography of an entire helical one-dimensional cobalt diiodide nanostructure encapsulated within a SWNT. This material has an unprecedented twisted double tetrahedral chain structure arising from a rotation of Co2I4 units along its length. The complete nanostructure comprises two distinct regions with oppositely handed helices separated by a short disordered region. The encapsulating SWNT shows a commensurate ovoid distortion reflecting an unexpectedly strong interaction between the nanostructure and the SWNT.

Philp, Eilidh; Sloan, Jeremy; Kirkland, Angus I.; Meyer, Rüdiger R.; Friedrichs, Steffi; Hutchison, John L.; Green, Malcolm L. H.

2003-12-01

298

Boson pairs in a one-dimensional split trap  

SciTech Connect

We describe the properties of a pair of ultracold bosonic atoms in a one-dimensional harmonic trapping potential with a tunable zero-ranged barrier at the trap center. The full characterization of the ground state is done by calculating the reduced single-particle density, the momentum distribution, and the two-particle entanglement. We derive several analytical expressions in the limit of infinite repulsion (Tonks-Girardeau limit) and extend the treatment to finite interparticle interactions by numerical solution. As pair interactions in double wells form a fundamental building block for many-body systems in periodic potentials, our results have implications for a wide range of problems.

Murphy, D. S.; McCann, J. F.; Goold, J.; Busch, Th. [Department of Applied Mathematics and Theoretical Physics, Queen's University Belfast, Belfast, BT7 1NN, Northern Ireland (United Kingdom); Department of Physics, National University of Ireland, UCC, Cork (Ireland)

2007-11-15

299

Parallel solution of sparse one-dimensional dynamic programming problems  

NASA Technical Reports Server (NTRS)

Parallel computation offers the potential for quickly solving large computational problems. However, it is often a non-trivial task to effectively use parallel computers. Solution methods must sometimes be reformulated to exploit parallelism; the reformulations are often more complex than their slower serial counterparts. We illustrate these points by studying the parallelization of sparse one-dimensional dynamic programming problems, those which do not obviously admit substantial parallelization. We propose a new method for parallelizing such problems, develop analytic models which help us to identify problems which parallelize well, and compare the performance of our algorithm with existing algorithms on a multiprocessor.

Nicol, David M.

1989-01-01

300

Itinerant-electron, one-dimensional magnetic superlattices  

NASA Astrophysics Data System (ADS)

Self-consistent Hartree-Fock calculations are presented for a variety of heterogeneous systems consisting of one-dimensional arrays of itinerant paramagnets, ferromagnets, and antiferromagnets. Several aspects of the multilayers and interfaces are explored: enhancement and reduction of the local magnetic moments, magnetic coupling at the interfaces, magnetic arrangements within each film and among nonneighboring films, the global symmetry of the systems, frustration, orientation of the various moments with respect to an outside applied field, and magnetic-field-induced transitions. The various situations exhibit a rich structure and a wealth of possible magnetic effects.

Hood, Randolph Q.; Falicov, L. M.

1991-11-01

301

Analytical approach for collective diffusion: One-dimensional homogeneous lattice.  

PubMed

Diffusion of particles adsorbed on the homogeneous one-dimensional chain was investigated using a theoretical approach and kinetic Monte Carlo simulations. The concentration dependencies of the center-of-mass and Fickian diffusion coefficients have been calculated for some representative values of lateral interactions between adsorbed particles. The analytical dependencies have been compared with the numerical data. The perfect coincidence of the data obtained by the two quite different methods clearly demonstrates that the analytical expressions for the diffusion coefficients derived in the framework of the approach based on the non-equilibrium statistical operator exactly describe the particle migration in the lattice gas systems. PMID:25053311

Tarasenko, Alexander

2014-07-21

302

Phase transitions in one-dimensional steady state hydrothermal flows  

NASA Astrophysics Data System (ADS)

The paper sets out necessary conditions for the existence of a phase transition in a steady state one-dimensional vertical hydrothermal flow. The entropy inequality (reflecting the presence of capillarity) and a thermodynamical inequality at the phase boundary are combined to delineate the region of permissible flow states in the mass-energy flow plane. In particular, it is shown that for small mass flow/permeability ratios the configuration consisting of single-phase liquid lying over a vapor-dominated two-phase fluid is not stable. These and other results are discussed in the context of several field examples, including Kawah Kamojang (Indonesia) and Wairakei (New Zealand).

Young, R. M.

1996-08-01

303

One-dimensional Rydberg gas in a magnetoelectric trap.  

PubMed

We study the quantum properties of Rydberg atoms in a magnetic Ioffe-Pritchard trap which is superimposed by a homogeneous electric field. Trapped Rydberg atoms can be created in long-lived electronic states exhibiting a permanent electric dipole moment of several hundred Debye. The resulting dipole-dipole interaction in conjunction with the radial confinement is demonstrated to give rise to an effectively one-dimensional ultracold Rydberg gas with a macroscopic interparticle distance. We derive analytical expressions for the electric dipole moment and the required linear density of Rydberg atoms. PMID:17930435

Mayle, Michael; Hezel, Bernd; Lesanovsky, Igor; Schmelcher, Peter

2007-09-14

304

Zener tunneling in one-dimensional organic semiconductors  

NASA Astrophysics Data System (ADS)

Tunneling effect in one-dimensional organic semiconductors in the presence of an external electric field is studied within the framework of a tight-binding model and a nonadiabatic dynamical method. It is found that under a high electric field, electrons can transit from the valence band (VB) to the conduction band (CB), which is demonstrated to be Zener tunneling in organic semiconductors. The results also indicate a field-induced insulator-metal transition accompanied by the vanishing of the energy gap. It is found that, after the field is turned off, the Peierls phase cannot be recovered.

Liu, W.; Li, Y.; Sun, Z.; Liu, D. S.; Xie, S. J.

2008-06-01

305

Feshbach molecules in a one-dimensional optical lattice  

SciTech Connect

We present the theory of a pair of atoms in a one-dimensional optical lattice interacting via a narrow Feshbach resonance. Using a two-channel description of the resonance, we derive analytic results for the scattering states inside the continuum band and the discrete bound states outside the band. We identify a Fano resonance profile, and the survival probability of a molecule when swept through the Bloch band of scattering states by varying an applied magnetic field. We discuss how these results may be used to investigate the importance of the structured nature of the continuum in experiments.

Nygaard, N.; Piil, R.; Moelmer, K. [Lundbeck Foundation Theoretical Center for Quantum System Research, Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark)

2008-02-15

306

Lattice-induced resonances in one-dimensional bosonic systems.  

PubMed

We study the resonant effects produced when a Feshbach dimer crosses a scattering continuum band of atoms in an optical lattice. We numerically obtain the exact spectrum of two particles in a one-dimensional lattice and develop an effective atom-dimer Hamiltonian that accurately captures resonant effects. The lattice-induced resonances lead to the formation of bound states simultaneously above and below the scattering continuum and significantly modify the curvature of the dimer dispersion relation. The nature of the atom-dimer coupling depends strongly on the parity of the dimer state leading to a novel coupling in the case of negative parity dimers. PMID:21770514

von Stecher, Javier; Gurarie, Victor; Radzihovsky, Leo; Rey, Ana Maria

2011-06-10

307

Numerical computations on one-dimensional inverse scattering problems  

NASA Technical Reports Server (NTRS)

An approximate method to determine the index of refraction of a dielectric obstacle is presented. For simplicity one dimensional models of electromagnetic scattering are treated. The governing equations yield a second order boundary value problem, in which the index of refraction appears as a functional parameter. The availability of reflection coefficients yield two additional boundary conditions. The index of refraction by a k-th order spline which can be written as a linear combination of B-splines is approximated. For N distinct reflection coefficients, the resulting N boundary value problems yield a system of N nonlinear equations in N unknowns which are the coefficients of the B-splines.

Dunn, M. H.; Hariharan, S. I.

1984-01-01

308

Numerical computations on one-dimensional inverse scattering problems  

NASA Technical Reports Server (NTRS)

An approximate method to determine the index of refraction of a dielectric obstacle is presented. For simplicity one dimensional models of electromagnetic scattering are treated. The governing equations yield a second order boundary value problem, in which the index of refraction appears as a functional parameter. The availability of reflection coefficients yield two additional boundary conditions. The index of refraction by a k-th order spline which can be written as a linear combination of B-splines is approximated. For N distinct reflection coefficients, the resulting N boundary value problems yield a system of N nonlinear equations in N unknowns which are the coefficients of the B-splines.

Dunn, M. H.; Hariharan, S. I.

1983-01-01

309

Log-periodic modulation in one-dimensional random walks  

NASA Astrophysics Data System (ADS)

We have studied the diffusion of a single particle on a one-dimensional lattice. It is shown that, for a self-similar distribution of hopping rates, the time dependence of the mean-square displacement follows an anomalous power law modulated by logarithmic periodic oscillations. The origin of this modulation is due to the dependence of the diffusion coefficient on the length scale. Both the random walk exponent and the period of the modulation are analytically calculated and confirmed by Monte Carlo simulations.

Padilla, L.; Mártin, H. O.; Iguain, J. L.

2009-01-01

310

One-dimensional leakage-flow vibration instabilities  

SciTech Connect

Simple boundary conditions, pressure losses, and channel geometries necessary for the unstable, rigid-body translational vibrations of the wall of a one-dimensional leakage flow channel are identified. General expressions for the flow damping and stiffness forces acting on the vibrating channel wall are derived and specific results are given for channels with wall friction, point pressure losses, sharp-edged constrictions, and diverging or converging widths. The minimum conditions necessary for dynamic and static (divergence) instability were found to be an upstream point pressure loss and a diverging channel width with a finite length throat region, respectively. 7 refs., 2 tabs.

Mulcahy, T.M.

1987-01-01

311

Semiclassical study of the one-dimensional hydrogen molecule.  

PubMed

The hydrogen molecule, as a restricted four-body problem, is a mixed chaotic system and is studied in this work as an extension of the helium atom. Several types of one-dimensional periodic orbits have been studied for this two-fixed-center system starting from some known orbits for the one-fixed-center system (helium atom). The hydrogen molecule has been studied by means of a semiclassical formalism. The single quantization of some periodic orbits are shown. These orbits are used to form a global quantization of the hydrogen molecule. Electronic energies of this nonintegrable molecular system are obtained with nonsingle semiclassical quantization. PMID:19045468

López-Castillo, A

2008-09-01

312

Edge-localized states in quantum one-dimensional lattices  

SciTech Connect

In one-dimensional quantum lattice models with open boundaries, we find and study localization at the lattice edge. We show that edge-localized eigenstates can be found in both bosonic and fermionic systems, specifically, in the Bose-Hubbard model with on-site interactions and in the spinless fermion model with nearest-neighbor interactions. We characterize the localization through spectral studies via numerical diagonalization and perturbation theory through considerations of the eigenfunctions and through the study of explicit time evolution. We concentrate on few-particle systems, showing how more complicated edge states appear as the number of particles is increased.

Pinto, Ricardo A.; Haque, Masudul; Flach, Sergej [Max-Planck-Institut fuer Physik komplexer Systeme, Noethnitzer Str. 38, 01187 Dresden (Germany)

2009-05-15

313

Space charge effects in field emission: One dimensional theory  

NASA Astrophysics Data System (ADS)

The current associated with field emission is greatly dependent on the electric field at the emitting electrode. This field is a combination of the electric field in vacuum and the space charge created by the current. The latter becomes more important as the current density increases. Here, a study is performed using a modified classical one dimensional (1D) Child-Langmuir description that allows for exact solutions in order to characterize the contributions due to space charge. Methods to connect the 1D approach to an array of periodic three dimensional structures are considered.

Rokhlenko, A.; Jensen, K. L.; Lebowitz, J. L.

2010-01-01

314

Transverse optical mode in a one-dimensional Yukawa chain.  

PubMed

A transverse optical mode was observed in a one-dimensional Yukawa chain. Charged particles, suspended in a strongly coupled dusty plasma, were arranged in a 1D periodic structure. Particle displacement in the direction perpendicular to the chain was restored by the confining potential. The dispersion relation of phonons was measured, verifying that the optical mode has negative dispersion, with phase and group velocities that are oppositely directed. A theoretical dispersion relation is presented and compared to the experiment and a molecular dynamics simulation. PMID:14754122

Liu, Bin; Avinash, K; Goree, J

2003-12-19

315

Fast numerical method for modelling one-dimensional diffraction gratings  

SciTech Connect

Based on the generalised source method, a new method for calculating the light diffraction on one-dimensional dielectric diffraction gratings with an arbitrary profile is proposed. The method is an alternative to the widely used Fourier modal method because it possesses the same possibilities in defining different grating profiles; however, it has a significant advantage in calculating complex-shaped gratings because it requires many fewer mathematical operations. The applicability of the method is shown by comparing the calculation results by this method with the results obtained by the conventional methods of light diffraction calculation on the gratings. (laser applications and other topics in quantum electronics)

Shcherbakov, A A; Tishchenko, A V [MEPhI National Research Nuclear University, Moscow (Russian Federation)

2010-08-27

316

Tracking bacterial movements using a one-dimensional fringe system.  

PubMed

Movements of individual E. coli bacteria in solution are detected by a one-dimensional fringe system formed in the focal region of two crossed laser beams. The time modulation of the scattered light intensity is used to deduce the instantaneous speed of the bacterial motion as it enters into the focal region. A method is described as being capable of testing the isotropic speed distribution function without the complications associated with the finite size and structural effects that influence the interpretation of the conventional light-scattering spectra. PMID:19684654

Holz, M; Chen, S H

1978-05-01

317

One-dimensional magnetopolymeric nanostructures with tailored sizes  

Microsoft Academic Search

Ultra-high aspect ratio nanofibers composed of poly(vinyl alcohol) and CoFe2O4 nanoparticles (PVA\\/CoFe2O4) and moderate aspect ratio nanofibers composed of poly(vinyl chloride) and Fe3O4 nanoparticles (PVC\\/Fe3O4) have been prepared. Magnetopolymeric one-dimensional (1D) nanostructures with any diameter and length can be prepared by template synthesis using anodic aluminum oxide (AAO) followed by the replication methods presented in this work. These replication methods

J. Martín; M. Vázquez; M. Hernández-Vélez; C. Mijangos

2008-01-01

318

On the Supercritical One Dimensional Age Dependent Branching Processes  

Microsoft Academic Search

Let $\\\\{Z(t); t \\\\geqq 0\\\\}$ be a one dimensional age dependent branching process with offspring probability generating function (pgf) $h(s) \\\\equiv \\\\sum^\\\\infty_{j=0} p_js^j$ and lifetime distribution function $G(t)$ (see Section 2 for definitions). If $m(t) \\\\equiv EZ(t)$ is the mean function let $Y(t) = Z(t)\\/m(t)$. Our objective in this paper is to study the limiting behavior of the process $\\\\{Y(t);

Krishna B. Athreya

1969-01-01

319

Phase sticking in one-dimensional Josephson junction chains  

NASA Astrophysics Data System (ADS)

We studied current-voltage characteristics of long one-dimensional Josephson junction chains with Josephson energy much larger than charging energy, EJ?EC. In this regime, typical I-V curves of the samples consist of a supercurrent-like branch at low-bias voltages followed by a voltage-independent chain current branch, Ichain at high bias. Our experiments showed that Ichain is not only voltage-independent but it is also practically temperature-independent up to T=0.7TC. We have successfully model the transport properties in these chains using a capacitively shunted junction model with nonlinear damping.

Ergül, Adem; Schaeffer, David; Lindblom, Magnus; Haviland, David B.; Lidmar, Jack; Johansson, Jan

2013-09-01

320

Reflection and coalescence between independent one-dimensional Brownian paths  

Microsoft Academic Search

Take two independent one-dimensional processes as follows: (Bt,t?[0,1]) is a Brownian motion with B0=0, and (?t,t?[0,1]) has the same law as (B1?t,t?[0,1]); in other words, ?1=0 and ? can be seen as Brownian motion running backwards in time. Define (?t,t?[0,1]) as being the function that is obtained by reflecting B on ?. Then ? is still a Brownian motion. Similar

Florin Soucaliuc; Bálint Tóth; Wendelin Werner

2000-01-01

321

Quantum Criticality of Quasi-One-Dimensional Topological Anderson Insulators  

NASA Astrophysics Data System (ADS)

We present an analytic theory of quantum criticality in the quasi-one-dimensional topological Anderson insulators of class AIII and BDI. We describe the systems in terms of two parameters (g, ?) representing localization and topological properties, respectively. Surfaces of half-integer valued ? define phase boundaries between distinct topological sectors. Upon increasing system size, the two parameters exhibit flow similar to the celebrated two-parameter flow describing the class A quantum Hall insulator. However, unlike the quantum Hall system, an exact analytical description of the entire phase diagram can be given. We check the quantitative validity of our theory by comparison to numerical transfer matrix computations.

Altland, Alexander; Bagrets, Dmitry; Fritz, Lars; Kamenev, Alex; Schmiedt, Hanno

2014-05-01

322

Saturable discrete vector solitons in one-dimensional photonic lattices  

SciTech Connect

Localized vectorial modes, with equal frequencies and mutually orthogonal polarizations, are investigated both analytically and experimentally in a one-dimensional photonic lattice with defocusing saturable nonlinearity. It is shown that these modes may span over many lattice elements and that energy transfer among the two components is both phase and intensity dependent. The transverse electrically polarized mode exhibits a single-hump structure and spreads in cascades in saturation, while the transverse magnetically polarized mode exhibits splitting into a two-hump structure. Experimentally such discrete vector solitons are observed in lithium niobate lattices for both coherent and mutually incoherent excitations.

Vicencio, Rodrigo A. [Max Planck Institute of Physics of Complex Systems, D-01187 Dresden (Germany); Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Santiago (Chile); Smirnov, Eugene; Rueter, Christian E.; Kip, Detlef [Institute of Physics and Physical Technologies, Clausthal University of Technology, D-38678 Clausthal-Zellerfeld (Germany); Stepic, Milutin [Department of Optical Technologies, National Institute of Metrology, D-38116 Braunschweig, Germany (Germany); Vinca Institute of Nuclear Sciences, P.O.B. 522, 11001 Belgrade (Serbia)

2007-09-15

323

Experimental observation of one-dimensional quantum holographic imaging  

NASA Astrophysics Data System (ADS)

We report the experimental observation of quantum holographic imaging of one-dimensional object with entangled photon pairs, generated in a spontaneous parametric down-conversion process. The signal photons play both roles of ``object wave'' and ``reference wave'' in holography but are recorded by a point detector providing only encoding information, while the idler photons travel freely and are locally manipulated with spatial resolution. The holographic image is formed by the two-photon correlation measurement, although both the signal and idler beams are incoherent. Three types of quantum holography schemes are analyzed according to the detection regime of the signal photons.

Song, Xin-Bing; Xu, De-Qin; Wang, Hai-Bo; Xiong, Jun; Zhang, Xiangdong; Cao, De-Zhong; Wang, Kaige

2013-09-01

324

New universal bifurcation scenario in one-dimensional trimodal maps  

NASA Astrophysics Data System (ADS)

By means of star products and high precision numerical calculation, an abnormal phenomenon is found in period- p-tupling bifurcation processes in one-dimensional trimodal maps. A route of transition to chaos, presented by a right-associative non-normal star product, breaks the Feigenbaum's metric universality, namely, the conventional Feigenbaum's successive rates exhibit a strong divergence. To overcome the divergence, an approximate scheme of accelerating convergence is proposed; and the Feigenbaum scenario is included as a special case in the new bifurcation scenario. It will provide access to understanding non-normal star products and their corresponding renormalization.

Zhou, Zhong; Cao, Ke-Fei; Peng, Shou-Li

2008-05-01

325

Spatial stochastic resonance in one-dimensional Ising systems.  

PubMed

The one-dimensional Ising model is analytically studied in a spatially periodic and oscillatory external magnetic field using the transfer-matrix method. For low enough magnetic field intensities the correlation between the external magnetic field and the response in magnetization presents a maximum for a given temperature. The phenomenon can be interpreted as a resonance phenomenon induced by the stochastic heat bath. This "spatial stochastic resonance" is realized in the equilibrium state and not as a dynamical response to the external time-periodic driving. PMID:11970258

Néda, Z; Rusz, A; Ravasz, E; Lakdawala, P; Gade, P M

1999-10-01

326

Breakdown of Thermalization in Finite One-Dimensional Systems  

SciTech Connect

We use quantum quenches to study the dynamics and thermalization of hard core bosons in finite one-dimensional lattices. We perform exact diagonalizations and find that, far away from integrability, few-body observables thermalize. We then study the breakdown of thermalization as one approaches an integrable point. This is found to be a smooth process in which the predictions of standard statistical mechanics continuously worsen as the system moves toward integrability. We establish a direct connection between the presence or absence of thermalization and the validity or failure of the eigenstate thermalization hypothesis, respectively.

Rigol, Marcos [Department of Physics, Georgetown University, Washington, D.C. 20057 (United States)

2009-09-04

327

Polarization hydrodynamics in a one-dimensional polariton condensate  

NASA Astrophysics Data System (ADS)

We study the hydrodynamics of a nonresonantly pumped polariton condensate in a quasi-one-dimensional quantum wire taking into account the spin degree of freedom. We clarify the relevance of the Landau criterion for superfluidity in this dissipative two-component system. Two Cherenkov-like critical velocities are identified corresponding to the opening of different channels of radiation: one of (damped) density fluctuations and another of (weakly damped) polarization fluctuations. We determine the drag force exerted onto an external obstacle and propose experimentally measurable consequences of the specific features of the fluctuations of polarization.

Larré, P.-É.; Pavloff, N.; Kamchatnov, A. M.

2013-12-01

328

Numerical study of the one-dimensional quantum compass model  

NASA Astrophysics Data System (ADS)

The ground state magnetic phase diagram of the one-dimensional quantum compass model (QCM) is studied using the numerical Lanczos method. A detailed numerical analysis of the low energy excitation spectrum is presented. The energy gap and the spin-spin correlation functions are calculated for finite chains. Two kind of the magnetic long-range orders, the Néel and a type of the stripe-antiferromagnet, in the ground state phase diagram are identified. Based on the numerical analysis, the first and second order quantum phase transitions in the ground state phase diagram are identified.

Mahdavifar, S.

2010-09-01

329

Numerical study of the one-dimensional quantum compass model  

Microsoft Academic Search

The ground state magnetic phase diagram of the\\u000a one-dimensional quantum compass model (QCM) is studied using the\\u000a numerical Lanczos method. A detailed numerical analysis of the low\\u000a energy excitation spectrum is presented. The energy gap and the\\u000a spin-spin correlation functions are calculated for finite chains.\\u000a Two kind of the magnetic long-range orders, the Néel\\u000a and a type of the stripe-antiferromagnet,

Saeed Mahdavifar

2010-01-01

330

Quantum phase transition in the one-dimensional compass model  

NASA Astrophysics Data System (ADS)

We introduce a one-dimensional model which interpolates between the Ising model and the quantum compass model with frustrated pseudospin interactions ?iz?i+1z and ?ix?i+1x , alternating between even and/or odd bonds, and present its exact solution by mapping to quantum Ising models. We show that the nearest-neighbor pseudospin correlations change discontinuously and indicate divergent correlation length at the first-order quantum phase transition. At this transition, one finds the disordered ground state of the compass model with high degeneracy 2×2N/2 in the limit of N?? .

Brzezicki, Wojciech; Dziarmaga, Jacek; Ole?, Andrzej M.

2007-04-01

331

Thermoelectric properties of one-dimensional graphene antidot arrays  

NASA Astrophysics Data System (ADS)

We investigate the thermoelectric properties of one-dimensional (1D) graphene antidot arrays by nonequilibrium Green's function method. We show that by introducing antidots to the pristine graphene nanoribbon the thermal conductance can be reduced greatly while keeping the power factor still high, thus leading to an enhanced thermoelectric figure of merit (ZT). Our numerical results indicate that ZT values of 1D antidot graphene arrays can be up to unity, which means the 1D graphene antidot arrays may be promising for thermoelectric applications.

Yan, Yonghong; Liang, Qi-Feng; Zhao, Hui; Wu, Chang-Qin; Li, Baowen

2012-07-01

332

Evaluation of one dimensional analytical models for vegetation canopies  

NASA Technical Reports Server (NTRS)

The SAIL model for one-dimensional homogeneous vegetation canopies has been modified to include the specular reflectance and hot spot effects. This modified model and the Nilson-Kuusk model are evaluated by comparing the reflectances given by them against those given by a radiosity-based computer model, Diana, for a set of canopies, characterized by different leaf area index (LAI) and leaf angle distribution (LAD). It is shown that for homogeneous canopies, the analytical models are generally quite accurate in the visible region, but not in the infrared region. For architecturally realistic heterogeneous canopies of the type found in nature, these models fall short. These shortcomings are quantified.

Goel, Narendra S.; Kuusk, Andres

1992-01-01

333

Calculating Ancestors in One-Dimensional Cellular Automata  

NASA Astrophysics Data System (ADS)

One-dimensional cellular automata are dynamical systems characterized by discreteness (in space and time), determinism and local interaction. We present a procedure to calculate the ancestors for a given sequence of states, which is based on a special kind of graph called subset diagram. We use this diagram to specify subset tables for calculating ancestors which are not Garden-of-Eden sequences, hence the process is able to yield ancestors in several generations. Some examples are illustrated using the cellular automaton Rule 110 which is the most interesting automaton of two states and three neighbors.

Mora, Juan Carlos Seck Tuoh; Martínez, Genaro Juárez; McIntosh, Harold V.

334

Spontaneous rotation in one-dimensional systems of cold atoms  

NASA Astrophysics Data System (ADS)

We theoretically study harmonically trapped one-dimensional Bose gases (e.g., L7i , N23a , K39 , R87b , etc.) with multibands occupied, focusing on effects of higher-energy bands. Combining the Ginzburg-Landau theory with bosonization techniques, we predict that the repulsive interaction between higher-band bosons and the quantum fluctuation can induce the ground state with a finite angular momentum around the trapped axis. In this state, the Z2 reflection symmetry (clockwise or anticlockwise rotations) is spontaneously broken.

Tokuno, Akiyuki; Sato, Masahiro

2008-07-01

335

A series of manganese-carboxylate coordination polymers exhibiting diverse magnetic properties.  

PubMed

The hydrothermal reactions of an asymmetrical 4-(4-carboxyphenylamino)-3,5-dinitrobenzoic acid (H2cpdba), MnCl2.4H2O, or together with 2,2'-bipyridine (2,2'-bpy) or 4,4'-bipyridine (4,4'-bpy) afford three novel molecule-based magnetic coordination polymers [Mn(cpdba)]n (1), ([Mn2(cpdba)2(2,2'-bpy)2(H2O)2].H2O)n (2) and ([Mn2(cpdba)2(4,4'-bpy)].2H2O)n (3). Compound 1 has a 3D acentric coordination network containing carboxylate-bridged 1D ladder-like manganese chains with spin-canted antiferromagnetism (J = -3.51 cm(-1) for the coupling along the ladder legs, and zJ' = 0.22 cm(-1) for coupling along the ladder rungs), whereas compounds 2 and 3 crystallize in the centrosymmetric space groups P1 and C2/c, respectively. 2 exhibits a 1D chain structure, which is extended into a 3D supramolecular network by pi-pi stacking interactions, while 3 features a quite complex 3D network built up from the cpdba(2-) and 4,4'-bpy spacers as well as the carboxylate-bridged Mn(II) chains. Both 2 and 3 show weak antiferromagnetic coupling interactions (J = -0.55 cm(-1) for 2), and a field-induced spin-flop magnetic transition can also be observed in 2 at ca. 3.2 T at 2 K. PMID:18827942

Li, Wei; Jia, Hong-Peng; Ju, Zhan-Feng; Zhang, Jie

2008-10-21

336

(Bis(1,2,4-triazol-1-yl)methane)silver(I) phosphino complexes: structures and spectroscopic properties of mixed-ligand coordination polymers.  

PubMed

Adducts of the ligand bis(1,2,4-triazol-1-yl)methane (tz(2)(CH(2))) of the form AgX:tz(2)(CH(2)):ER(3):MeCN (1:1:1:x) (X = NO(3), R = Ph, E = P, As, or Sb, x = 1 or 2; X = NO(2), ClO(4), O(3)SCF(3), E = P, R = Ph, x = 0, 1 or 2; X = NO(3), ClO(4), E = P, R = cy, x = 1; X = ClO(4), E = As, R = Ph, x = 2) and AgNO(3):tz(2)(CH(2)):P(o-tolyl)(3) (2:2:1) have been synthesized and characterized in the solid state and in solution by analyses, spectral (IR, far-IR, (1)H and (13)C NMR, ESI MS data) data, and conductivity measurements. In the one-dimensional polymers (characterized by X-ray studies) AgNO(3):tz(2)(CH(2)):PPh(3):CH(3)CN (1:1:1:1), AgClO(4):tz(2)(CH(2)):PPh(3):CH(3)CN (1:1:1:2), AgNO(3):tz(2)(CH(2)):AsPh(3): CH(3)CN (1:1:1:2), and AgNO(3):tz(2)(CH(2)):SbPh(3):CH(3)CN (1:1:1:2), the silver atom can be regarded as four-coordinate, the tz(2)(CH(2)) ligands behaving as bridging groups rather than chelates, with no pair of ligands being dominant, quasi-trans, in their interactions. The AgNO(3):tz(2)(CH(2)):P(o-tolyl)(3) (2:2:1) adduct is a two-dimensional polymer containing two independent silver atoms, one four-coordinated unsymmetrically by a pair of triazolyl rings, one P(o-tolyl)(3), and a unidentate nitrate and the second by a quasi-symmetrical O(2)NO chelate and a pair of equivalent triazolyl rings. PMID:15018540

Effendy; Marchetti, Fabio; Pettinari, Claudio; Pettinari, Riccardo; Ricciutelli, Massimo; Skelton, Brian W; White, Allan H

2004-03-22

337

N-(sulfoethyl) iminodiacetic acid-based lanthanide coordination polymers: Synthesis, magnetism and quantum Monte Carlo studies  

SciTech Connect

A series of lanthanide coordination polymers have been obtained through the hydrothermal reaction of N-(sulfoethyl) iminodiacetic acid (H{sub 3}SIDA) and Ln(NO{sub 3}){sub 3} (Ln=La, 1; Pr, 2; Nd, 3; Gd, 4). Crystal structure analysis exhibits that lanthanide ions affect the coordination number, bond length and dimension of compounds 1-4, which reveal that their structure diversity can be attributed to the effect of lanthanide contraction. Furthermore, the combination of magnetic measure with quantum Monte Carlo(QMC) studies exhibits that the coupling parameters between two adjacent Gd{sup 3+} ions for anti-anti and syn-anti carboxylate bridges are -1.0 Multiplication-Sign 10{sup -3} and -5.0 Multiplication-Sign 10{sup -3} cm{sup -1}, respectively, which reveals weak antiferromagnetic interaction in 4. - Graphical abstract: Four lanthanide coordination polymers with N-(sulfoethyl) iminodiacetic acid were obtained under hydrothermal condition and reveal the weak antiferromagnetic coupling between two Gd{sup 3+} ions by Quantum Monte Carlo studies. Highlights: Black-Right-Pointing-Pointer Four lanthanide coordination polymers of H{sub 3}SIDA ligand were obtained. Black-Right-Pointing-Pointer Lanthanide ions play an important role in their structural diversity. Black-Right-Pointing-Pointer Magnetic measure exhibits that compound 4 features antiferromagnetic property. Black-Right-Pointing-Pointer Quantum Monte Carlo studies reveal the coupling parameters of two Gd{sup 3+} ions.

Zhuang Guilin, E-mail: glzhuang@zjut.edu.cn [Institute of Industrial Catalysis, College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032 (China); Chen Wulin [Institute of Industrial Catalysis, College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032 (China); Zheng Jun [Center of Modern Experimental Technology, Anhui University, Hefei 230039 (China); Yu Huiyou [Institute of Industrial Catalysis, College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032 (China); Wang Jianguo, E-mail: jgw@zjut.edu.cn [Institute of Industrial Catalysis, College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032 (China)

2012-08-15

338

One-Dimensional Shell Effects in Thin Metal Films  

NASA Astrophysics Data System (ADS)

During epitaxial growth and thermal processing of metal thin films on semiconductors, the system often self-organizes into domains or islands of preferred heights. This extra stability for specific film thicknesses has an electronic origin; confinement of the electrons in the film causes the formation of quantum-well states, which cross the Fermi level periodically as the film thickness increases. These periodic Fermi level crossings give rise to one-dimensional shell effects, akin to the shell effects associated with the periodic table. As a result, large variations in film properties are expected, including the surface energy that determines the stability and preferred heights of the film, the work function and other surface properties, and the superconducting gap and transition temperature. This talk will present highlights in recent advances on this subject, including angle-resolved photoemission measurements of the electronic structure and experimental and theoretical determinations of the amplitude, damping, period, and phase relationships of the property variations. The roles played by the substrate and the effects of phonon scattering will also be discussed. See T. Miller, M. Y. Chou, and T.-Chiang, ``Phase relations associated with one-dimensional shell effects in thin metal films,'' Phys. Rev. Lett. 102, 236803 (2009), and references therein.

Chiang, T.-C.

2010-03-01

339

Sliding regime of conduction in “one-dimensional Wigner crystal”  

NASA Astrophysics Data System (ADS)

We study theoretically transport properties of one-dimensional system of interacting electrons pinned by an impurity. Long-range Coulomb interaction in such a system is known to induce a 4kF electron density modulation characterized by extremely slow, slower than any power law, decay of the density correlations which can be described as a one-dimensional Wigner crystal. We study non-stationary regime of conduction corresponding to sliding of the 1D Wigner crystal depinned by the applied voltage. In this regime the dc current is accompanied by current oscillations with frequency f=Ibar/e. We calculate I-V curves and ac current generated by sliding. Our approach is based on the ideas of Luttinger liquid. We study also the case of magnetic impurity and show that applied voltage induces not only the electrical current, but also the spin current as well, in other words, the current becomes spin polarized. We find that a spin bias applied to the system contributes to electric current both in case of magnetic and non-magnetic impurity, and this is related to violation of the spin-charge separation at the impurity site.

Artemenko, S. N.; Shapiro, D. S.; Vakhitov, R. R.; Remizov, S. V.

2012-06-01

340

Correlation functions of one-dimensional impenetrable anyons  

NASA Astrophysics Data System (ADS)

In the last years we have witnessed the experimental realization of many one-dimensional physical systems. This has renewed the interest of theoretical physicists in computing relevant quantities for such models, which are experimental accessible. We have investigated the field-field correlation functions of a model of one-dimensional impenetrable anyons which is relevant for systems that can be realized with edges of the electron liquids in the Fractional Quantum Hall Effect (FQHE) regime. Varying the statistics parameter, the correlation functions of this model, interpolate between the ones for impenetrable bosons and free fermions. We have computed the large distance asymptotic behavior of the field-field correlator at finite temperatures solving a Riemann-Hilbert problem associated with the integrable system of nonlinear partial differential equations characterizing the correlator. As a preliminary step we have obtained a Fredholm determinant representation using two methods: the anyonic generalization of Lenard's formula and the summation of form factors. We show that the leading term of the asymptotics is oscillatory with the period of oscillation proportional with the statistics parameter. Also as the statistics parameter approaches the free fermionic point the second leading term becomes comparable in magnitude with the leading term but with opposite phase producing fermionic beats.

Patu, Ionel Ovidiu

341

Generating arbitrary one-dimensional dose profiles using rotational therapy.  

PubMed

Conformal radiation therapy can be delivered using several methods: intensity-modulated radiotherapy (IMRT) at fixed gantry angles, through the continuous gantry rotation of linac (rotational arc therapy), or by a dedicated treatment unit such as tomotherapy. The recently developed volumetric modulated arc therapy (VMAT), a form of rotational arc therapy, has attracted lots of attention from investigators to explore its capability of generating highly conformal dose to the target. The main advanced features of VMAT are the variable dose rate and gantry rotation speed. In this paper, we present a theoretical framework of generating arbitrary one-dimensional dose profiles using rotational arc therapy to further explore the new degree of freedom of the VMAT technique. This framework was applied to design a novel technique for total body irradiation (TBI) treatment, where the desired dose distribution can be simplified by a one-dimensional profile. The technique was validated using simulations and experimental measurements. The preliminary results demonstrated that the new TBI technique using either dynamic MLC only, variable dose rate only, or a combination of dynamic MLC and variable dose rate can achieve arbitrary dose distribution in one dimension, such as uniform dose to target and lower dose to critical organ. This technique does not require the use of customized compensators, nor large treatment rooms as in the conventional extended SSD technique. PMID:20924133

Zhuang, Tingliang; Wu, Qiuwen

2010-10-21

342

Bound states of dipolar bosons in one-dimensional systems  

NASA Astrophysics Data System (ADS)

We consider one-dimensional tubes containing bosonic polar molecules. The long-range dipole-dipole interactions act both within a single tube and between different tubes. We consider arbitrary values of the externally aligned dipole moments with respect to the symmetry axis of the tubes. The few-body structures in this geometry are determined as a function of polarization angles and dipole strength by using both essentially exact stochastic variational methods and the harmonic approximation. The main focus is on the three-, four- and five-body problems in two or more tubes. Our results indicate that in the weakly coupled limit the intertube interaction is similar to a zero-range term with a suitable rescaled strength. This allows us to address the corresponding many-body physics of the system by constructing a model where bound chains with one molecule in each tube are the effective degrees of freedom. This model can be mapped onto one-dimensional Hamiltonians for which exact solutions are known.

Volosniev, A. G.; Armstrong, J. R.; Fedorov, D. V.; Jensen, A. S.; Valiente, M.; Zinner, N. T.

2013-04-01

343

Dislocation-mediated melting of one-dimensional Rydberg crystals  

SciTech Connect

We consider cold Rydberg atoms in a one-dimensional optical lattice in the Mott regime with a single atom per site at zero temperature. An external laser drive with Rabi frequency {Omega} and laser detuning {Delta} creates Rydberg excitations whose dynamics is governed by an effective spin-chain model with (quasi) long-range interactions. This system possesses intrinsically a large degree of frustration resulting in a ground-state phase diagram in the ({Delta},{Omega}) plane with a rich topology. As a function of {Delta}, the Rydberg blockade effect gives rise to a series of crystalline phases commensurate with the optical lattice that form a so-called devil's staircase. The Rabi frequency {Omega}, on the other hand, creates quantum fluctuations that eventually lead to a quantum melting of the crystalline states. Upon increasing {Omega}, we find that generically a commensurate-incommensurate transition to a floating Rydberg crystal that supports gapless phonon excitations occurs first. For even larger {Omega}, dislocations within the floating Rydberg crystal start to proliferate and a second, Kosterlitz-Thouless-Nelson-Halperin-Young dislocation-mediated melting transition finally destroys the crystalline arrangement of Rydberg excitations. This latter melting transition is generic for one-dimensional Rydberg crystals and persists even in the absence of an optical lattice. The floating phase and the concomitant transitions can, in principle, be detected by Bragg scattering of light.

Sela, Eran; Garst, Markus [Institut fuer Theoretische Physik, Universitaet zu Koeln, Zuelpicher Str. 77, DE-50937 Koeln (Germany); Punk, Matthias [Physik Department, Technische Universitaet Muenchen, James-Franck-Strasse, DE-85748 Garching (Germany); Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States)

2011-08-15

344

Hydrogen peroxide stabilization in one-dimensional flow columns.  

PubMed

Rapid hydrogen peroxide decomposition is the primary limitation of catalyzed H(2)O(2) propagations in situ chemical oxidation (CHP ISCO) remediation of the subsurface. Two stabilizers of hydrogen peroxide, citrate and phytate, were investigated for their effectiveness in one-dimensional columns of iron oxide-coated and manganese oxide-coated sand. Hydrogen peroxide (5%) with and without 25 mM citrate or phytate was applied to the columns and samples were collected at 8 ports spaced 13 cm apart. Citrate was not an effective stabilizer for hydrogen peroxide in iron-coated sand; however, phytate was highly effective, increasing hydrogen peroxide residuals two orders of magnitude over unstabilized hydrogen peroxide. Both citrate and phytate were effective stabilizers for manganese-coated sand, increasing hydrogen peroxide residuals by four-fold over unstabilized hydrogen peroxide. Phytate and citrate did not degrade and were not retarded in the sand columns; furthermore, the addition of the stabilizers increased column flow rates relative to unstabilized columns. These results demonstrate that citrate and phytate are effective stabilizers of hydrogen peroxide under the dynamic conditions of one-dimensional columns, and suggest that citrate and phytate can be added to hydrogen peroxide before injection to the subsurface as an effective means for increasing the radius of influence of CHP ISCO. PMID:21700356

Schmidt, Jeremy T; Ahmad, Mushtaque; Teel, Amy L; Watts, Richard J

2011-09-25

345

Hydrogen peroxide stabilization in one-dimensional flow columns  

NASA Astrophysics Data System (ADS)

Rapid hydrogen peroxide decomposition is the primary limitation of catalyzed H 2O 2 propagations in situ chemical oxidation (CHP ISCO) remediation of the subsurface. Two stabilizers of hydrogen peroxide, citrate and phytate, were investigated for their effectiveness in one-dimensional columns of iron oxide-coated and manganese oxide-coated sand. Hydrogen peroxide (5%) with and without 25 mM citrate or phytate was applied to the columns and samples were collected at 8 ports spaced 13 cm apart. Citrate was not an effective stabilizer for hydrogen peroxide in iron-coated sand; however, phytate was highly effective, increasing hydrogen peroxide residuals two orders of magnitude over unstabilized hydrogen peroxide. Both citrate and phytate were effective stabilizers for manganese-coated sand, increasing hydrogen peroxide residuals by four-fold over unstabilized hydrogen peroxide. Phytate and citrate did not degrade and were not retarded in the sand columns; furthermore, the addition of the stabilizers increased column flow rates relative to unstabilized columns. These results demonstrate that citrate and phytate are effective stabilizers of hydrogen peroxide under the dynamic conditions of one-dimensional columns, and suggest that citrate and phytate can be added to hydrogen peroxide before injection to the subsurface as an effective means for increasing the radius of influence of CHP ISCO.

Schmidt, Jeremy T.; Ahmad, Mushtaque; Teel, Amy L.; Watts, Richard J.

2011-09-01

346

Optical parametric oscillation in one-dimensional microcavities  

NASA Astrophysics Data System (ADS)

We present a comprehensive investigation of optical parametric oscillation in resonantly excited one-dimensional semiconductor microcavities with embedded quantum wells. Such solid-state structures feature a fine control over light-matter coupling and produce a photonic/polaritonic mode fan that is exploited for the efficient emission of parametric beams. We implement an energy-degenerate optical parametric oscillator with balanced signal and idler intensities via a polarization-inverting mechanism. In this paper, we (i) precisely review the multimode photonic/polaritonic structure of individual emitters, (ii) provide a thorough comparison between experiment and theory, focusing on the power and the threshold dependence on the exciton-photon detuning, (iii) discuss the influence of inhomogeneous broadening of the excitonic transition and finite size, and (iv) find that a large exciton-photon detuning is a key parameter to reach a high output power and a high conversion efficiency. Our study highlights the predictive character of the polariton interaction theory and the flexibility of one-dimensional semiconductor microcavities as a platform to study parametric phenomena.

Lecomte, Timothée; Ardizzone, Vincenzo; Abbarchi, Marco; Diederichs, Carole; Miard, Audrey; Lemaitre, Aristide; Sagnes, Isabelle; Senellart, Pascale; Bloch, Jacqueline; Delalande, Claude; Tignon, Jerome; Roussignol, Philippe

2013-04-01

347

Assessing the inherent uncertainty of one-dimensional diffusions.  

PubMed

In this paper we assess the inherent uncertainty of one-dimensional diffusion processes via a stochasticity classification which provides an à la Mandelbrot categorization into five states of uncertainty: infra-mild, mild, borderline, wild, and ultra-wild. Two settings are considered. (i) Stopped diffusions: the diffusion initiates from a high level and is stopped once it first reaches a low level; in this setting we analyze the inherent uncertainty of the diffusion's maximal exceedance above its initial high level. (ii) Stationary diffusions: the diffusion is in dynamical statistical equilibrium; in this setting we analyze the inherent uncertainty of the diffusion's equilibrium level. In both settings general closed-form analytic results are established, and their application is exemplified by stock prices in the stopped-diffusions setting, and by interest rates in the stationary-diffusions setting. These results provide a highly implementable decision-making tool for the classification of uncertainty in the context of one-dimensional diffusions. PMID:23410302

Eliazar, Iddo; Cohen, Morrel H

2013-01-01

348

Linear scaling for quasi-one-dimensional systems  

NASA Astrophysics Data System (ADS)

Atomistic simulations that calculate the atomic interactions on the fly from an electronic structure calculation using an independent particle approximation are nowadays the most important ab initio simulation scheme. A major limiting factor of this method is the cubic scaling of the algorithms used. Recently we presented an expression for the grand canonical potential describing a system of uncorrelated fermions [F. R. Krajewski and M. Parrinello, Phys. Rev. B 71, 233105 (2005)]. We found that this expression can be evaluated within a linear scaling computational effort using Monte Carlo methods, leading to linear scaling algorithms for metals and semiconductors [F. R. Krajewski and M. Parrinello, Phys. Rev. B 73, 041105 (2006)]. We also mentioned that for one-dimensional systems the electronic structure calculation can be performed within linear scaling with a deterministic algorithm. In this work we extend this idea and show that the electronic structure problem can be solved exactly within the linear scaling computational effort for quasi-one-dimensional systems, avoiding the application of Monte Carlo techniques and the resulting noise on the electronic properties. The linear scaling scheme is applied to various types of tight binding carbon nanotubes with up to 105 atoms.

Krajewski, Florian R.; Parrinello, Michele

2006-09-01

349

Magnetic Stimulation of One-Dimensional Neuronal Cultures  

PubMed Central

Transcranial magnetic stimulation is a remarkable tool for neuroscience research, with a multitude of diagnostic and therapeutic applications. Surprisingly, application of the same magnetic stimulation directly to neurons that are dissected from the brain and grown in vitro was not reported to activate them to date. Here we report that central nervous system neurons patterned on large enough one-dimensional rings can be magnetically stimulated in vitro. In contrast, two-dimensional cultures with comparable size do not respond to excitation. This happens because the one-dimensional pattern enforces an ordering of the axons along the ring, which is designed to follow the lines of the magnetically induced electric field. A small group of sensitive (i.e., initiating) neurons respond even when the network is disconnected, and are presumed to excite the entire network when it is connected. This implies that morphological and electrophysiological properties of single neurons are crucial for magnetic stimulation. We conjecture that the existence of a select group of neurons with higher sensitivity may occur in the brain in vivo as well, with consequences for transcranial magnetic stimulation.

Rotem, Assaf; Moses, Elisha

2008-01-01

350

New insights from one-dimensional spin glasses  

NASA Astrophysics Data System (ADS)

Spin glasses are paradigmatic models that deliver concepts relevant for a variety of systems. However, despite ongoing research spanning several decades, there remain many fundamental open questions. Concepts from the solution of the mean-field model, such as ergodicity breaking, aging, ultrametricity, and the existence of an instability line at finite magnetic fields known as the Almeida-Thouless line, have been applied to realistic short-range spin-glass models as well as to fields as diverse as structural biology, computer science and financial analysis. Rigorous analytical results are difficult to obtain for spin glasses, in particular for realistic short-range systems. Therefore typical studies involve large-scale numerical simulations, as well as the use of efficient algorithms and improved model systems. It is of paramount importance to understand which properties of the mean-field solution carry over to short-range systems. The use of one-dimensional spin glasses with (diluted) power-law interactions has been instrumental in elucidating the properties of spin-glass systems. Large system sizes can be simulated, and different universality classes ranging from the mean-field to the short-range case can be probed by tuning the power-law exponent of the interactions. Recent results on spin-glass problems using the aforementioned one-dimensional model are presented with special emphasis on the existence of a spin-glass state in a field.

Katzgraber, Helmut G.

2010-03-01

351

Different dimensional coordination polymers with 4,4'-oxybis(benzoate): Syntheses, structures and properties  

NASA Astrophysics Data System (ADS)

Five transition-metal coordination polymers, namely, [Zn7Cl6(oba)4]n (1), [Cd7Cl6(oba)4]n (2), [Zn(oba)(H2O)]n (3), [Ag2(oba)]n (4) and [Co(oba)(H2O)2]n (5) (H2oba=4,4?-oxydibenzoic acid), have been achieved under hydrothermal conditions and structurally characterized by IR, elemental analyses, X-ray single-crystal diffraction and TGA. The X-ray single-crystal diffraction reveals that compounds 1 and 2 are isomorphism, featuring pillared-layer 3D motifs, in which the 2D inorganic layers (Zn6Cl7)n (or (Cd6Cl7)n) are connected by oba2- pillars. Compound 3 exhibits 1D stair-like chain and extends to a 3D network by two different interchain O-H-O hydrogen bonding interactions while compound 4 features wave chains and stretches to 2D layer by interchain Ag-O weak contacts. Compound 5 shows 2D network in which Co-chains are pillared by oba2- ligand and then forms a 3D network by four different O-H-O hydrogen bonding interactions. Furthermore, 1-4 exhibit luminescent properties at a solid state and 5 shows antiferromagnetic behavior.

Lun, Huijie; Li, Yamin; Zhang, Xudong; Yang, Jing-He; Xiao, Changyu; Xu, Yanqing; Li, Junrui

2014-07-01

352

Self-assembled nanoscale coordination polymers with trigger release properties for effective anticancer therapy.  

PubMed

Nanoscale coordination polymers (NCPs) are self-assembled from metal ions and organic bridging ligands, and can overcome many drawbacks of existing drug delivery systems by virtue of tunable compositions, sizes and shapes, high drug loadings, ease of surface modification and intrinsic biodegradability. Here we report the self-assembly of zinc bisphosphonate NCPs that carry 48±3?wt% cisplatin prodrug and 45±5?wt% oxaliplatin prodrug. In vivo pharmacokinetic studies in mice show minimal uptake of pegylated NCPs by the mononuclear phagocyte system and excellent blood circulation half-lives of 16.4±2.9 and 12.0±3.9?h for the NCPs carrying cisplatin and oxaliplatin, respectively. In all tumour xenograft models evaluated, including CT26 colon cancer, H460 lung cancer and AsPC-1 pancreatic cancer, pegylated NCPs show superior potency and efficacy compared with free drugs. As the first example of using NCPs as nanotherapeutics with enhanced antitumour activities, this study establishes NCPs as a promising drug delivery platform for cancer therapy. PMID:24964370

Liu, Demin; Poon, Christopher; Lu, Kuangda; He, Chunbai; Lin, Wenbin

2014-01-01

353

Terahertz phase contrast imaging of sorption kinetics in porous coordination polymer nanocrystals using differential optical resonator.  

PubMed

The enhancement of light-matter coupling when light is confined to wavelength scale volumes is useful both for studying small sample volumes and increasing the overall sensing ability. At these length scales, nonradiative interactions are of key interest to which near-field optical techniques may reveal new phenomena facilitating next-generation material functionalities and applications. Efforts to develop novel chemical or biological sensors using metamaterials have yielded innovative ideas in the optical and terahertz frequency range whereby the spatially integrated response over a resonator structure is monitored via the re-radiated or leaked light. But although terahertz waves generally exhibit distinctive response in chemical molecules or biological tissue, there is little absorption for subwavelength size sample and therefore poor image contrast. Here, we introduce a method that spatially resolves the differential near-field phase response of the entire resonator as a spectral fingerprint. By simultaneously probing two metallic ring resonators, where one loaded with the sample of interest, the differential phase response is able to resolve the presence of guest molecules (e.g. methanol) as they are adsorbed or released within the pores of a prototypical porous coordination polymer. PMID:24921804

Blanchard, F; Sumida, K; Wolpert, C; Tsotsalas, M; Tanaka, T; Doi, A; Kitagawa, S; Cooke, D G; Furukawa, S; Tanaka, K

2014-05-01

354

A family of 2D and 3D coordination polymers involving a trigonal tritopic linker.  

PubMed

Five new coordination polymers, namely, [Zn(2)(H(2)O)(2)(BBC)](NO(3))(DEF)(6) (DUT-40), [Zn(3)(H(2)O)(3)(BBC)(2)] (DUT-41), [(C(2)H(5))(2)NH(2)][Zn(2)(BBC)(TDC)](DEF)(6)(H(2)O)(7) (DUT-42), [Zn(10)(BBC)(5)(BPDC)(2)(H(2)O)(10)](NO(3))(DEF)(28)(H(2)O)(8) (DUT-43), and [Co(2)(BBC)(NO(3))(DEF)(2)(H(2)O)](DEF)(6)(H(2)O) (DUT-44), where BBC--4,4',4''-(benzene-1,3,5-triyl-tris(benzene-4,1-diyl))tribenzoate, TDC--2,5-thiophenedicarboxylate, BPDC--4,4'-biphenyldicarboxylate, DEF--,N-diethylformamide, were obtained under solvothermal conditions and structurally characterized. It has been shown that compounds DUT-40, DUT-41 and DUT-44 exhibit 2D layered structures with large hexagonal channels. Utilization of additional angular dicarboxylic TDC linker led to the formation of the DUT-42 compound with the structure consisting of three interpenetrated 3D networks. Using the linear co-linker dicarboxylic BPDC, DUT-43 was obtained which forms a complicated 3D architecture arising from the polycatenation of triple-layered 2D building units and 2D single layer units. The pore accessibility of the synthesized compounds in the liquid phase was proved by the adsorption of dye molecules. PMID:22293901

Hauptvogel, Ines Maria; Bon, Volodymyr; Grünker, Ronny; Baburin, Igor A; Senkovska, Irena; Mueller, Uwe; Kaskel, Stefan

2012-04-14

355

Synthesis, crystal structure and photoluminescent properties of four lanthanide 5-nitroisophthalate coordination polymers  

NASA Astrophysics Data System (ADS)

Four new lanthanide coordination polymers, [Y(Hnip)(nip)(H 2O)]·H 2O ( 1), [ Ln(Hnip)(nip)(H 2O) 2]·2H 2O [ Ln=Eu( 2), Tb( 3)] and [Y(nip) 2]·(H 24,4'-bpy) 0.5 ( 4) [5-nip=5-nitroisophthalate, 4,4'-bpy=4,4'-bipyridine], have been hydrothermally synthesized and structurally characterized. Compound 1 features novel lanthanide-carboxylate groups chains composed of three samehanded helical strands intersecting each other through hinged lanthanide atoms, and these chains are cross-linked by phenylene moieties of carboxylate ligands into a 2D layer structure. Compounds 2 and 3 are isomorphous, and contain 1D catenanelike Ln-O-C-O- Ln chains, which are interconnected by phenylene moieties into 2D layer structures. Compound 4, however, displays a 3D architecture sustained by strong hydrogen bonding interactions between the protonated 4,4'-bpy and the carboxyl oxygen atom from [Y 2(nip) 4] 2- with 2D layer structure, and 4,4'-bpy as the guest molecules exist in bilayer channel. The studies for the thermal stabilities of the four compounds show that compound 4 is more stable than other compounds. Compound 2 emits characteristic red luminescence of Eu 3+ ions at room temperature, and its luminescent lifetime and quantum efficiency has been determined.

Huang, Yan; Yan, Bing; Shao, Min

2009-04-01

356

Solvothermal synthesis of four polyoxometalate-based coordination polymers including diverse Ag(I)···? interactions.  

PubMed

Four 3D POM-based silver coordination polymers, namely, [Ag17(ptz)11(PW12O40)2]n (1), [Ag17(ptz)11(PMo12O40)2]n (2), [Ag12(ptz)6(CN)2(SiW12O40)]n (3), and [Ag19(ptz)8(H2ptz)(H3ptz)(AgP5W30O110)·7H2O]n (4), have been obtained by solvothermal reaction of AgNO3 and 5-phenyl-1H-tetrazole (Hptz) ligand in the presence of four types of polyoxometalates. Structural analysis shows that four types of Ag(I)···? interactions, m-?(1), m/p-?(2), o/m-?(2), and o/m/p-?(3), were observed in compounds 1-4, depending on the polyoxometalates used. The in situ generated CN(-) ion in compound 3 shows unprecedented mixed ? and ? bonding modes, similar to the C2(2-) ion in well-studied silver acetylides. For 4, the Na(+) ion in the Preyssler heteropolyoxoanion, [NaP5W30O110](14-), was exchanged by Ag(I) under solvothermal conditions, generating a novel [AgP5W30O110](14-) anion. In addition, the photoluminescence behavior of 1-4 was also investigated. PMID:24392969

Liang, Min-Xia; Ruan, Chan-Zi; Sun, Di; Kong, Xiang-Jian; Ren, Yan-Ping; Long, La-Sheng; Huang, Rong-Bin; Zheng, Lan-Sun

2014-01-21

357

Two coordination polymers of manganese(II) isophthalate and their preparation, structures, and magnetic properties  

SciTech Connect

Two manganese coordination polymers, [Mn{sub 2}(ip){sub 2}(dmf)]{center_dot}dmf (1) and [Mn{sub 4}(ip){sub 4}(dmf){sub 6}]{center_dot}2dmf (2) (ip=isophthalate; dmf=N,N-dimethylformamide), have been synthesized and characterized. X-ray crystal structural data reveal that compound 1 crystallizes in triclinic space group P-1, a=9.716(3) A, b=12.193(3) A, c=12.576(3) A, {alpha}=62.19(2) Degree-Sign , {beta}=66.423(17) Degree-Sign , {gamma}=72.72(2) Degree-Sign , Z=2, while compound 2 crystallizes in monoclinic space group Cc, a=19.80(3) A, b=20.20(2) A, c=18.01(3) A, {beta}=108.40(4) Degree-Sign , Z=4. Variable-temperature magnetic susceptibilities of compounds 1 and 2 exhibit overall weak antiferromagnetic coupling between the adjacent Mn(II) ions. - Graphical abstract: Three-dimensional porous and two-dimensional layered manganese isophthalates have been prepared. Magnetic susceptibility measurements exhibit overall weak antiferromagnetic interactions between the Mn(II) ions in both compounds. Highlights: Black-Right-Pointing-Pointer Two manganese isophthalates have been prepared. Black-Right-Pointing-Pointer Compound 1 adopts a three-dimensional porous structure. Black-Right-Pointing-Pointer Compound 2 adopts a two-dimensional layered structure. Black-Right-Pointing-Pointer Magnetic properties of both compounds are investigated.

Chen Jinxi, E-mail: chenjinxi@seu.edu.cn [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Wang Jingjing [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Ohba, Masaaki [Department of Chemistry, Faculty of Science, Kyushu University, Fukuoka (Japan)

2012-01-15

358

Complexes of Ag(I), Hg(I) and Hg(II) with multidentate pyrazolyl-pyridine ligands: From mononuclear complexes to coordination polymers via helicates, a mesocate, a cage and a catenate.  

PubMed

The coordination chemistry of a series of di- and tri-nucleating ligands with Ag(I), Hg(I) and Hg(II) has been investigated. Most of the ligands contain two or three N,N'-bidentate chelating pyrazolyl-pyridine units pendant from a central aromatic spacer; one contains three binding sites (2 + 3 + 2-dentate) in a linear sequence. A series of thirteen complexes has been structurally characterised displaying a wide range of structural types. Bis-bidentate bridging ligands react with Ag(I) to give complexes in which Ag(I) is four-coordinate from two bidentate donors, but the complexes can take the form of one-dimensional coordination polymers, or dinuclear complexes (mesocate or helicate). A tris-bidentate triangular ligand forms a complicated two-dimensional coordination network with Ag(I) in which Ag...Ag contacts, as well as metal-ligand coordination bonds, play a significant role. Three dinuclear Hg(I) complexes were isolated which contain an {Hg2}2+ metal-metal bonded core bound to a single bis-bidentate ligand which can span both metal ions. Also characterised were a series of Hg(II) complexes comprising a simple mononuclear four-coordinate Hg(II) complex, a tetrahedral Hg(II)4 cage which incorporates a counter-ion in its central cavity, a trinuclear double helicate, and a trinuclear catenated structure in which two long ligands have spontaneously formed interlocked metallomacrocyclic rings thanks to cyclometallation of two of the Hg(II) centres. PMID:17060986

Argent, Stephen P; Adams, Harry; Riis-Johannessen, Thomas; Jeffery, John C; Harding, Lindsay P; Clegg, William; Harrington, Ross W; Ward, Michael D

2006-11-14

359

A hydrotalcitelike Ce(III) coordination polymer pillared by Keggin anions: Synthesis, single crystal structure and photocatalysis  

Microsoft Academic Search

A new coordination polymer, H[{Ce(H2O)5}2{Ce(pdc)2(H2O)4}{Ce(pdc)3}(PW12O40)]•2H2O 1 (pdc=pyridine-2,6 -dicarboxylate), has been obtained by the hydrothermal reaction. It exhibits a 3D hydrotalcitelike structure constructed from 2D cationic [{Ce(H2O)5}2{Ce(pdc)2(H2O)4}{Ce(pdc)3}]2+ layers pillared by ?-Keggin [PW12O40]3? anions. Polymer 1 is active for photocatalytic H2 evolution under UV irradiation.

Bi-fang Meng; Wan-sheng You; Xian-feng Sun; Fan Zhang; Mei-ying Liu

2011-01-01

360

A heteropolymetallic coordination polymer containing alkaline-earth (Ae) cation, lanthanide (Ln) cation and alkali (A) cation  

Microsoft Academic Search

A heteropolymetallic coordination polymer, [Ba2Tb4Na4(pdc)10(H2O)24]·(H2O)11, H2pdc=pyridine-2,6-dicarboxylic acid, has been successfully designed, synthesized under hydrothermal condition, and characterized by elemental analysis, thermal analysis, IR spectrum, luminescence, as well as X-ray crystallography. Three different kinds of metal cations (Ae, Ln and A) could be connected simultaneously by a pdc2? ligand with coordination mode i. A fundamental block consisting of 14-membered mixed-metal Ba(II)–Tb(III)–Na(I)

Qi Shuai; Sanping Chen; Huiling Geng; Shengli Gao

361

A high activity nitrogen-doped carbon catalyst for oxygen reduction reaction derived from polyaniline-iron coordination polymer  

NASA Astrophysics Data System (ADS)

A nitrogen-doped carbon catalyst with trace iron (N/C/Fe-c, 0.54 wt.% Fe) has been prepared through pyrolysis of polyaniline (PANI)-iron coordination polymer. Electrochemical results demonstrate that N/C/Fe-c catalyst displays excellent oxygen reduction reaction (ORR) catalytic activity and shows almost the same diffusion-limited current density for ORR as Pt/C catalyst in acid media. FTIR and XPS measurements indicate that Fe3+ ions coordinate with N atoms of the PANI chains and N/C/Fe-c has a high ratio of graphitic N, which are responsible for high ORR activity.

Wang, Guanghua; Jiang, Kezhu; Xu, Mingli; Min, Chungang; Ma, Baohua; Yang, Xikun

2014-11-01

362

Relation of Water Molecule Coordination in Polar Polymers to Reverse Osmosis Desalination Efficiency.  

National Technical Information Service (NTIS)

Polymer water and salt sorption and permeabilities were measured for a series of polymers based on poly(epichlorohydrin) or on the copolymer of epichlorohydrin and ethylene oxide with various ratios of epichlorohydrin to ethylene oxide. Water and salt per...

H. Strathmann R. Devarakonda

1971-01-01

363

One-dimensional plasma photonic crystals with sinusoidal densities  

NASA Astrophysics Data System (ADS)

Properties of electromagnetic waves with normal and oblique incidence have been studied for one-dimensional plasma layers with sinusoidal densities. Wave transmittance as a function of wave frequency exhibits photonic band gaps characteristic of photonic crystals. For periodic structures, increasing collision frequency is demonstrated to lead to greater absorption, increasing the modulation factor enlarges the gap width, and increasing incidence angle can change the gap locations of the two polarizations. If a defect layer is introduced by inserting a new plasma layer in the center, a defect mode may appear within the gap. Periodic number, collision frequency, and modulation factor can affect magnitude of the defect mode. The incidence angle enables the frequency to be tuned. Defect layer thickness affects both frequency and number of defect modes. These results may provide theoretical guidance in designing tunable narrow-band filters.

Qi, L.; Shang, L.; Zhang, S.

2014-01-01

364

One-dimensional growth mechanism of amorphous boron nanowires  

NASA Astrophysics Data System (ADS)

High-density of arrays of self-oriented boron nanowires grown on silicon substrates were synthesized by radio-frequency magnetron sputtering with a target of highly pure boron and boron oxide mixture using argon as the sputtering atmosphere. TEM studies show that the conventional growth mechanisms such as Frank screw-dislocation mechanism and the vapor-liquid-solid mechanisms are not suitable for the one-dimensional growth of boron nanowires. The oxide-assisted cluster-solid mechanism for the Si and Ge crystalline nanowires is not completely suitable for our case. The vapor-cluster-solid mechanism is proposed for the well-aligned growth of the amorphous boron nanowires.

Wang, Y. Q.; Duan, X. F.; Cao, L. M.; Wang, W. K.

2002-06-01

365

One-dimensional relativistic dynamics with scaling formalism  

NASA Astrophysics Data System (ADS)

In one dimension, we investigate dynamics using special relativity only, but make no statement regarding any particular insight into the nature of the spacetime continuum. Indeed, we do away completely with any kind of formal tensor algebra or differential topology, but do incorporate scaling into our calculations. The purpose here is primarily pedagogical, as an extension to the standard undergraduate treatment of special relativity, but it is also a calculational tool, to be able to determine the motion of objects in a one-dimensional case even with accelerations and forces, without having to use the full general relativistic treatment. To illustrate this, we directly compare relativistic to Newtonian or non-relativistic motions for particularly instructive selected systems.

Asadi-Zeydabadi, Masoud; Sadun, Alberto C.

2013-01-01

366

Enhanced multiple exciton generation in quasi-one-dimensional semiconductors.  

PubMed

The creation of a single electron-hole pair (i.e., exciton) per incident photon is a fundamental limitation for current optoelectronic devices including photodetectors and photovoltaic cells. The prospect of multiple exciton generation per incident photon is of great interest to fundamental science and the improvement of solar cell technology. Multiple exciton generation is known to occur in semiconductor nanostructures with increased efficiency and reduced threshold energy compared to their bulk counterparts. Here we report a significant enhancement of multiple exciton generation in PbSe quasi-one-dimensional semiconductors (nanorods) over zero-dimensional nanostructures (nanocrystals), characterized by a 2-fold increase in efficiency and reduction of the threshold energy to (2.23 ± 0.03)E(g), which approaches the theoretical limit of 2E(g). Photovoltaic cells based on PbSe nanorods are capable of improved power conversion efficiencies, in particular when operated in conjunction with solar concentrators. PMID:21766838

Cunningham, Paul D; Boercker, Janice E; Foos, Edward E; Lumb, Matthew P; Smith, Anthony R; Tischler, Joseph G; Melinger, Joseph S

2011-08-10

367

Strongly-Refractive One-Dimensional Photonic Crystal Prisms  

NASA Technical Reports Server (NTRS)

One-dimensional (1D) photonic crystal prisms can separate a beam of polychromatic electromagnetic waves into constituent wavelength components and can utilize unconventional refraction properties for wavelength dispersion over significant portions of an entire photonic band rather than just near the band edges outside the photonic band gaps. Using a ID photonic crystal simplifies the design and fabrication process and allows the use of larger feature sizes. The prism geometry broadens the useful wavelength range, enables better optical transmission, and exhibits angular dependence on wavelength with reduced non-linearity. The properties of the 1 D photonic crystal prism can be tuned by varying design parameters such as incidence angle, exit surface angle, and layer widths. The ID photonic crystal prism can be fabricated in a planar process, and can be used as optical integrated circuit elements.

Ting, David Z. (Inventor)

2004-01-01

368

One-Dimensional Quasi-Relativistic Particle in the Box  

NASA Astrophysics Data System (ADS)

The eigenvalues and eigenfunctions of the one-dimensional quasi-relativistic Hamiltonian (-?2c2d2/dx2 + m2c4)1/2 + Vwell(x) (the Klein-Gordon square-root operator with electrostatic potential) with the infinite square well potential Vwell(x) are studied. Eigenvalues represent energies of a "massive particle in the box" quasi-relativistic model. Approximations to eigenvalues ?n are given, uniformly in n, ?, m, c and a, with error less than C1?ca-1exp(-C2?-1mca)n-1. Here 2a is the width of the potential well. As a consequence, the spectrum is simple and the nth eigenvalue is equal to (n?/2 - ?/8)?c/a + O(1/n) as n ? ?. Non-relativistic, zero mass and semi-classical asymptotic expansions are included as special cases. In the final part, some L2 and L? properties of eigenfunctions are studied.

Kaleta, Kamil; Kwa?nicki, Mateusz; Ma?ecki, Jacek

2013-09-01

369

ICARUS: A general one-dimensional heat conduction code  

NASA Astrophysics Data System (ADS)

A computer code for calculating one dimensional planar, cylindrical or spherical conduction heat transfer is described. The model can account for material phase change (solidification or melting, multiple material regions, temperature dependent material properties and time or temperature dependent boundary conditions. Finite difference techniques are used to discretize the differential equations. The resulting system of tri-diagonal equations are solved using a standard tri-diagonal reduction method. The equations are formulated so that the solution can be fully implicit, fully explicit or a user specified degree of mix. Six sample problems that compare numerical predictions to analytical solutions are discussed. Operation of the computer code and all input variables are described. Input file listings and typical edits for the six sample problems are given.

Sutton, S. B.

1984-07-01

370

One-dimensional disk model simulation for klystron design  

SciTech Connect

In 1982, one of the authors (Okazaki), of Toshiba Corporation, wrote a one-dimensional, rigid-disk model computer program <1> to serve as a reliable design tool for the 150 MW klystron development project. This is an introductory note for the users of this program. While reviewing the so-called disk programs presently available, hypotheses such as gridded interaction gaps, a linear relation between phase and position, and so on, were found. These hypotheses bring serious limitations and uncertainties into the computational results. JPNDISK was developed to eliminate these defects, to follow the equations of motion as rigorously as possible, and to obtain self-consistent solutions for the gap voltages and the electron motion. Although some inaccuracy may be present in the relativistic region, JPNDISK, in its present form, seems a most suitable tool for klystron design; it is both easy and inexpensive to use.

Yonezawa, H.; Okazaki, Y.

1984-05-01

371

Entropic topological invariant for a gapped one-dimensional system  

NASA Astrophysics Data System (ADS)

We propose an order parameter for a general one-dimensional gapped system with an open boundary condition. The order parameter can be computed from the ground state entanglement entropy of some regions near one of the boundaries. Hence, it is well defined even in the presence of arbitrary interaction and disorder. We also show that it is invariant under a finite-depth local quantum circuit, suggesting its stability against an arbitrary local perturbation that does not close the energy gap. Further, it can unambiguously distinguish a Majorana chain from a trivial chain under global fermion parity conservation. We argue that the order parameter can be, in principle, measured in an optical lattice system.

Kim, Isaac H.

2014-06-01

372

Dynamics of an impurity in a one-dimensional lattice  

NASA Astrophysics Data System (ADS)

We study the non-equilibrium dynamics of an impurity in a harmonic trap that is kicked with a well-defined quasi-momentum, and interacts with a bath of free fermions or interacting bosons in a one-dimensional lattice configuration. Using numerical and analytical techniques we investigate the full dynamics beyond linear response, which allows us to quantitatively characterize states of the impurity in the bath for different parameter regimes. These vary from a tightly bound molecular state in a strongly interacting limit to a polaron (dressed impurity) and a free particle for weak interactions, with composite behaviour in the intermediate regime. These dynamics and different parameter regimes should be readily realizable in systems of cold atoms in optical lattices.

Massel, F.; Kantian, A.; Daley, A. J.; Giamarchi, T.; Törmä, P.

2013-04-01

373

Magnons in one-dimensional k-component Fibonacci structures  

NASA Astrophysics Data System (ADS)

We have studied the magnon transmission through of one-dimensional magnonic k-component Fibonacci structures, where k different materials are arranged in accordance with the following substitution rule: Sn(k)=Sn-1(k)Sn-k(k) (n ?k=0,1,2,…), where Sn(k) is the nth stage of the sequence. The calculations were carried out in exchange dominated regime within the framework of the Heisenberg model and taking into account the RPA approximation. We have considered multilayers composed of simple cubic spin-S Heisenberg ferromagnets, and, by using the powerful transfer-matrix method, the spin wave transmission is obtained. It is demonstrated that the transmission coefficient has a rich and interesting magnonic pass- and stop-bands structures, which depends on the frequency of magnons and the k values.

Costa, C. H.; Vasconcelos, M. S.

2014-05-01

374

Globally Synchronized Oscillations in AN One-Dimensional Cellular Automaton  

NASA Astrophysics Data System (ADS)

Using a genetic algorithm a population of one-dimensional binary cellular automata is evolved to perform a computational task for which the best evolved rules cause the concentration to display a period-three oscillation. One run is studied in which the final state reached by the best evolved rule consists of a regular pattern or domain ?, plus some propagating particles. It is shown that globally synchronized period-three oscillations can be obtained if the lattice size L is a multiple of the spatial periodicity S(?) of the domain. When L=m.S(?)-1 there is a cyclic particle reaction that keeps the system in two different phases and the concentration has a temporal periodicity that depends on the lattice size. The effects of random noise on the evolved cellular automata has also been investigated.

Jiménez-Morales, Francisco; Tomassini, Marco

375

Microwave properties of nonlinear one-dimensional quasiperiodic photonic crystals  

NASA Astrophysics Data System (ADS)

The nonlinear properties of quasi-periodic photonic crystals based on the Thue-Morse and Fibonacci sequence are investigated. We address the transmission properties of waves through one dimensional symmetric Fibonacci, and Thue-Morse system i.e., a quasiperiodic structure made up of two different dielectric materials (Rogers and air), in quarter wavelength condition, presenting in the one directions. The microwave spectra are calculated by using transfer matrix method in normal incidence geometry. In our results we present the self-similar features of the spectra and we also present the microwave properties through a return map of the transmission coefficients. We extract powerfully the band gaps of quasi-periodic multilayered structures, called `pseudo band gaps' often contain resonant states, which can be considered as a manifestation of numerous defects distributed along the structure. Taken together, the above two properties provide favorable conditions for the design of an all-microwave reflector.

Trabelsi, Y.; Kanzari, M.

2012-05-01

376

Quasi-one-dimensional transport in semiconductor microstructures  

NASA Astrophysics Data System (ADS)

We describe some of the physics peculiar to electron transport in quasi-one-dimensional systems in semiconductors, with particular reference to three systems in which it has been investigated: ultra-fine free-standing wires of doped GaAs, the split-gate high-electron-mobility transistor (with and without a back-gate to vary the carrier concentration), and vertical quantum pillars fabricated from multiple-barrier heterostructure material. They are all electron waveguide structures, characterized by <=0.1 ?m feature sizes in two of the three spatial dimensions, and they all exhibit phenomena quite different from those seen in macroscopic semiconductor structures. We try to identify the subset of this physics that may be exploitable, and comment on the more general relevance of this new physics to devices.

Kelly, M. J.; Potts, A.; Hamilton, A.; Tewordt, M.; Pepper, M.; Law, V. J.; Frost, J. E. F.; Ritchie, D. A.; Jones, G. A. C.; Hasko, D. G.; Ahmed, H.

1992-01-01

377

Out-of-equilibrium one-dimensional disordered dipole chain  

NASA Astrophysics Data System (ADS)

We consider a chain of one-dimensional dipole moments connected to two thermal baths with different temperatures. The system is in nonequilibrium steady state and heat flows through it. Assuming that fluctuation of the dipole moment is a small parameter, we develop an analytically solvable model for the problem. The effect of disorder is introduced by randomizing the positions of the dipole moments. We show that the disorder leads to Anderson-like transition from conducting to a thermal insulating state of the chain. It is shown that considered chain supports both ballistic and diffusive heat transports depending on the strength of the disorder. We demonstrate that nonequilibrium leads to the emergence of the long-range order between dipoles along the chain and make the conjecture that the interplay between nonequilibrium and next-to-nearest-neighbor interactions results in the emergence of long-range correlations in low-dimensional classical systems.

Dolgikh, Anton V.; Kosov, Daniel S.

2013-07-01

378

One-dimensional photonic crystal fishbone hybrid nanocavity with nanoposts  

NASA Astrophysics Data System (ADS)

We propose and investigate a one-dimensional photonic crystal (PhC) fishbone (FB) hybrid nanocavity lying on silver substrate with a horizontal air slot. With very few PhC periods, the confined transverse-magnetic, TM10 hybrid mode concentrated within the air slot shows high quality factor over effective mode volume ratio larger than 105?-3. Most importantly, this FB hybrid nanocavity allows formation of low-index nanoposts within the air slot without significantly affecting the mode properties. These nanoposts guarantee the structural stabilities under different environmental perturbations. Furthermore, capabilities of our proposed design in serving as optical sensors and tweezers for bio-sized nanoparticles are also investigated.

Lu, Tsan-Wen; Lin, Pin-Tso; Lee, Po-Tsung

2014-05-01

379

Equilibrium properties of a one-dimensional kinetic system.  

NASA Technical Reports Server (NTRS)

One-dimensional systems of N = 500 and 250 particles in equilibrium are numerically simulated utilizing the method of molecular dynamics. Periodic boundary conditions are imposed. The classical two-body interaction potential is short range, repulsive and has a corresponding finite force. The equations of state are determined for densities both less and greater than one. Corresponding theoretical isochores are determined from models based on nearest-neighbor interactions and on a truncated virial expansion, and a comparison is made with the experimental isochores. Time independent radial distributions are constructed numerically and discussed. A change of state from a solidlike state to a fluid-gas state based on the penetrability of the particles is predicted. The transition temperatures are estimated from the radial distribution functions and the nearest-neighbor model. Self-diffusion is observed and the corresponding constants are determined from the velocity autocorrelation functions.

Williams, J. H.; Joyce, G.

1973-01-01

380

Split Fermi seas in one-dimensional Bose fluids  

NASA Astrophysics Data System (ADS)

For the one-dimensional repulsive Bose gas (Lieb-Liniger model), we study a special class of highly excited states obtained by giving a finite momentum to subgroups of particles. These states, which correspond to "splitting" the ground-state Fermi-sea-like quantum number configuration, are zero-entropy states which display interesting properties more normally associated with ground states. Using a numerically exact method based on integrability, we study these states' excitation spectrum, density correlations, and momentum distribution functions. These correlations display power-law asymptotics and are shown to be accurately described by an effective multicomponent Tomonaga-Luttinger liquid theory whose parameters are obtained from the Bethe ansatz. The nonuniversal correlation prefactors are moreover obtained from integrability, yielding a completely parameter-free fit of the correlator asymptotics.

Fokkema, T.; Eliëns, I. S.; Caux, J.-S.

2014-03-01

381

One-dimensional modeling of piping flow erosion  

NASA Astrophysics Data System (ADS)

A process called "piping", which often occurs in water-retaining structures (earth-dams, dykes, levees), involving the formation and progression of a continuous tunnel between the upstream and downstream sides, is one of the main cause of structure failure. Starting with the diphasic flow volume equations and the jump equations including the erosion processes, a simplified one-dimensional model for two-phase piping flow erosion was developed. The numerical simulation based on constant input and output pressures showed that the particle concentration can be a significant factor at the very beginning of the process, resulting in the enlargement of the hole at the exit. However, it was concluded that this influence is a secondary factor: the dilute flow assumption, which considerably simplifies the description, is relevant here. To cite this article: D. Lachouette et al., C. R. Mecanique 336 (2008).

Lachouette, Damien; Golay, Frédéric; Bonelli, Stéphane

2008-09-01

382

Nanoscale template for the growth of one-dimensional nanostructures  

NASA Astrophysics Data System (ADS)

The functionalization of the anisotropic Ag(110) surface with a self-assembled silicon nanostripe grating prior to Co deposition has been studied in situ with scanning tunneling microscopy. At room temperature, Co atoms are adsorbed on top of the silicon nanostructures. As the diffusion rate of Co into the Si nanostripes is very low at this temperature, the formation of well-organized, identical Co nanolines arranged in parallel rows is observed. Upon annealing at 100 °C, Co atoms massively diffuse into the nanostripes, leading to the destruction of the Si array. The early stages of growth at room temperature indicate that the parallel Co nanolines are coupled and display short-range interaction. Our results show that the Ag(110) surface covered with a silicon nanostripe grating can be used as a template for the growth of identical and well-ordered one-dimensional nanostructures of various materials.

Dettoni, F.; Sahaf, H.; Moyen, E.; Masson, L.; Hanbücken, M.

2011-04-01

383

Chaos in a one-dimensional compressible flow  

NASA Astrophysics Data System (ADS)

We study the dynamics of a one-dimensional discrete flow with open boundaries—a series of moving point particles connected by ideal springs. These particles flow towards an inlet at constant velocity, pass into a region where they are free to move according to their nearest neighbor interactions, and then pass an outlet where they travel with a sinusoidally varying velocity. As the amplitude of the outlet oscillations is increased, we find that the resident time of particles in the chamber follows a bifurcating (Feigenbaum) route to chaos. This irregular dynamics may be related to the complex behavior of many particle discrete flows or is possibly a low-dimensional analogue of nonstationary flow in continuous systems.

Gerig, Austin; Hübler, Alfred

2007-04-01

384

Dissipationless kinetics of one-dimensional interacting fermions  

NASA Astrophysics Data System (ADS)

We study the problem of evolution of a density pulse of one-dimensional interacting fermions with a nonlinear single-particle spectrum. We show that, despite the non-Fermi-liquid nature of the problem, nonequilibrium phenomena can be described in terms of a kinetic equation for certain quasiparticles related to the original fermions by a nonlinear transformation which decouples the left- and right-moving excitations. Employing this approach, we investigate the kinetics of the phase-space distribution of the quasiparticles and thus determine the time evolution of the density pulse. This allows us to explore a crossover from the essentially free-fermion evolution for weak or short-range interaction to hydrodynamics emerging in the case of sufficiently strong, long-range interaction.

Protopopov, I. V.; Gutman, D. B.; Oldenburg, M.; Mirlin, A. D.

2014-04-01

385

Growth of One-Dimensional MnO2 Nanostructure  

NASA Astrophysics Data System (ADS)

Large scale MnO2 nanorods were controllably synthesized from the inexpensive precursors (e.g., manganese acetate, ammonium persulfate) via a facile one-step low temperature hydrothermal strategy. The crystal phase and microscopic morphology of the as-prepared MnO2 nanorods were characterized by X-ray powder diffraction (XRD) and scanning electron microscope (SEM). Through investigating the morphology evolution of MnO2 products in the whole synthesis process, a novel growth mechanism of these MnO2 nanorods was proposed, which may be efficiently extended to other material systems as a general approach towards one-dimensional nanostructures. The obtained MnO2 nanorods may have potential applications in Li-ion batteries and supercapacitors.

Lu, Pai; Xue, Dongfeng

386

Laughlin wave function and one-dimensional free fermions  

SciTech Connect

Making use of the well-known phase-space reduction in the lowest Landau level, we show that the Laughlin wave function for the {nu}=1/{ital m} case can be obtained exactly as a coherent-state representation of a one-dimensional (1D) wave function. The 1D system consists of {ital m} copies of free fermions associated with each of the {ital N} electrons, confined in a common harmonic well potential. Interestingly, the condition for this exact correspondence is found to incorporate Jain`s parton picture. We argue that this correspondence between the free fermions and quantum Hall effect is due to the mapping of the 1D system under consideration to the Gaussian unitary ensemble in the random matrix theory.

Panigrahi, P.K.; Sivakumar, M. [School of Physics, University of Hyderabad, Hyderabad-500 134 (India)] [School of Physics, University of Hyderabad, Hyderabad-500 134 (India)

1995-11-15

387

Counter Chemotactic Flow in Quasi-One-Dimensional Path  

NASA Astrophysics Data System (ADS)

Quasi-one-dimensional bidirectional particle flow including the effect of chemotaxis is investigated through a modification of the John-Schadschneider-Chowdhury-Nishinari model. Specifically, we permit multiple lanes to be shared by both directionally traveling particles. The relation between particle density and flux is studied for several evaporation rates of pheromone, and the following results are obtained: i) in the low-particle-density range, the flux is enlarged by pheromone if the pheromone evaporation rate is sufficiently low, ii) in the high particle-density range, the flux is largest at a reasonably high evaporation rate and, iii) if the evaporation rate is at the level intermediate between the above two cases, the flux is kept small in the entire range of particle densities. The mechanism of these behaviors is investigated by observing the spatiotemporal evolution of particles and the average cluster size in the system.

Fujii, Masashi; Awazu, Akinori; Nishimori, Hiraku

2009-07-01

388

The first cyclobutane-1,2,3,4-tetracarboxylate containing metal coordination polymer with three-dimensional framework  

Microsoft Academic Search

The hydrothermal reaction of cyclobutane-1,2,3,4-tetracarboxylic acid (H4CBTC) with Cd(NO3)2·4H2O yields the first CBTC containing metal coordination polymer with three-dimensional framework [Cd2(CBTC)(H2O)2]n (1), which is characterized by single-crystal X-ray diffraction analysis, IR spectroscopy and TG analysis.

Junhua Luo; Feilong Jiang; Ruihu Wang; Maochun Hong

2004-01-01

389

Thixotropic behavior of metal-containing coordination polymers: Melt viscosity of neutral aliphatic polyesters with Zn carboxylates  

Microsoft Academic Search

The viscosity behavior of polymer melts containing complexes formed between the neutralized polyester poly(diethylene glycol-co-succinic acid) and Zn acetates is discussed. The melt viscosity of these materials increases with the concentration of metal ions, and shows strong thixotropy and shear thinning. This behavior is attributed to the formation of coordination bonds between the electron donor groups within the polyester chain,

G. Liu; B. White; I. Vancso-Szmercsanyi; G. J. Vancso

1996-01-01

390

Restraining the motion of a ligand for modulating the structural phase transition in two isomorphic polar coordination polymers.  

PubMed

A structural phase transition induced by ligand motion was found in a new polar coordination polymer: [Cu(NCS)2(4-APy)2]n (4-APy = 4-aminopyridine). Restraining such motion in an isomorphic compound [Cu(NCS)2(4-MeAPy)2]n (4-MeAPy = 4-methylaminopyridine) results in distinct phase transition behaviour. These findings provide a new clue for modulating phase transition behaviour in known materials. PMID:24805838

Wang, Bao-Ying; Xu, Wei-Jian; Xue, Wei; Lin, Rui-Biao; Du, Zi-Yi; Zhou, Dong-Dong; Zhang, Wei-Xiong; Chen, Xiao-Ming

2014-06-28

391

Unique (3,12)-connected coordination polymers displaying high stability, large magnetocaloric effect and slow magnetic relaxation.  

PubMed

Two unique 3D coordination polymers based on octahedral [Ln6] (Ln = Gd (), Dy ()) clusters as nodes were synthesized, exhibiting a novel (3,12)-connected topology with the symbol of (4(20)·6(26)·8(20))(4(3))4. The magnetic studies reveal that shows a -?Sm = 46.6 J kg(-1) K(-1), falling among the largest values known to date, and displays slow magnetic relaxation behavior. Both and have high thermal and solvent stabilities. PMID:23722625

Hou, Yin-Ling; Xiong, Gang; Shi, Peng-Fei; Cheng, Rui-Rui; Cui, Jian-Zhong; Zhao, Bin

2013-07-11

392

Topologies and solid electric conductivities of two diverse silver 4-sulfobenzoate coordination polymers controlled by uncoordination and coordination 4-aminopyridine ligands  

NASA Astrophysics Data System (ADS)

Two new diverse silver 4-sulfobenzoate coordination polymers, {[Ag(4-sb)]·(4-apyH)}n (1) and [Ag2(4-apy)(4-sb)]n (2) where 4-sb is 4-sulfobenzoate dianion and 4-apy is 4-aminopyridine, were prepared by the strategy of different ratio of starting materials and characterized by single-crystal X-ray analysis, elemental analysis, IR spectra, TG analysis, fluorescence spectra and electric conductivity. The molecular structure of 1 is made up of alternating 2-D anionic {[Ag(4-sb)]-}n layers and 4-apyH cations. Complex 2 is a 3-D structure. Both of the molecular structures are pillared architectures. To assess the relationship between structures and properties, the detail topologies of two diverse coordination polymers were analyzed. Complex 1 possesses a 3,6,6-c 3-nodal net with kgd topological layers, while 2 shows a new 4,4,8-c network. The room-temperature solid conductivity of 1 is lower than that of 2, which is controlled by the weak interactions.

Zheng, Xiao-Feng; Zhu, Long-Guan

2013-05-01

393

Novel tin supramolecular compounds and coordination polymers: Influence of aromatic dicarboxylates on the crystal structures  

NASA Astrophysics Data System (ADS)

Six tin based coordination compounds containing pyridine-2,5-dicarboxylate (pydc), terephthalate (ta), or naphthalene-2,6-dicarboxylate (ndc) ligands have been synthesized hydro-/solvo-thermally and characterized by single crystal X-ray diffraction. Compounds 1 and 2 are polymorphs with chemical composition of Sn(Hpydc) 2 and have strikingly different 1D supramolecular structures due to the different linking mode of the monoprotonated pydc ligand. Compound 1, the major phase, crystallizes in the space group P2 1/ n ( a = 16.4038(8) Å, b = 48.092(2) Å, c = 19.0217(9) Å, ? = 90.066(1)°) and compound 2, the minor phase, crystallizes in the space group P2 1/ n ( a = 9.680(3) Å, b = 12.793(4) Å, c = 12.591(4) Å, ? = 108.703(7)°). Compound 3, Sn(pydc)(DMF), crystallizes in the space group P2 1/ c ( a = 11.4932(6) Å, b = 8.4885(5) Å, c = 12.0493(6) Å, ? = 100.568(1)°,) with infinite 1D helical chains extended along the crystallographic b-axis. Compound 4, Sn 2(O)(pydc), crystallizes in the space group C2/ c ( a = 13.5948(14) Å, b = 6.6759(7) Å, c = 20.200(2) Å, ? = 90.007(2)°), and is a 3D coordination polymer that contains edge-shared Sn 4O 2 clusters arranged into 1D stair-like structures that are stacked to form small channels. Compound 5, Sn 3(O)(ta) 2, which crystallizes in the space group P ?1 ( a = 6.9436(6) Å, b = 7.1505(6) Å, c = 19.1353(16) Å, ? = 83.714(1)°, ? = 89.686(1)°, ? = 64.034(1)°) and compound 6, Sn 3(O)(ndc) 2, which crystallizes in the space group P ?1 ( a = 7.0892(10) Å, b = 7.2714(10) Å, c = 23.400(3) Å, ? = 86.699(2)°, ? = 85.914(2)°, ? = 63.423(2)°), are structurally related and form tin oxide layers consisting of bridged Sn 3O clusters, that are connected to adjacent layers by the ta and ndc ligands, respectively.

Wibowo, Arief C.; Smith, Mark D.; zur Loye, Hans-Conrad

2011-03-01

394

Single-Crystal-to-Single-Crystal Transformations in One Dimensional Ag-Eu Helical System  

SciTech Connect

Single-crystal-to-single-crystal transformation of 1-D 4d-4f coordination polymers have been investigated for the first time. It displays high selectivity for Mg2+ and can be used as magnesium ion-selective luminescent probe. More importantly, we observed the transformation of meso-helical chain to rac-helical chain as a function of temperature.

Cai, Yue-Peng; Zhout, Xiu-Xia; Zhout, Zheng-Yuan; Zhu, Shi-Zheng; Thallapally, Praveen K.; Liu, Jun

2009-07-06

395

A comparative study of coordination between host polymers and Li + ions in UV-cured gel polymer electrolytes  

Microsoft Academic Search

Crosslinked gel polymer electrolytes are prepared via free radical photo-polymerization of 1,6-hexanediol diacrylate (HDDA) or tri(ethylene glycol) diacrylate (TEGDA) with 1 M LiClO4 dissolved in a solvent mixture of ethylene carbonate (EC) and propylene carbonate (PC). TEGDA-based gel polymer electrolytes containing a polar moiety of ethylene oxide exhibit relatively high ionic conductivities over a temperature range from ?15 to 65 °C in

Nam-Soon Choi; Jung-Ki Park

2009-01-01

396

First dicyanamide-bridged spin-crossover coordination polymer: synthesis, structural, magnetic, and spectroscopic studies.  

PubMed

We report here on the synthesis and characterisation of a first iron(II) spin-crossover coordination polymer with the dca spacer ligand, having the formula [Fe(aqin)2(dca)]ClO4.MeOH (aqin=8-aminoquinoline, dca=dicyanamide), which displays a two-step complete spin transition. Variable-temperature magnetic susceptibility measurements and Mössbauer spectroscopy have revealed that the two relatively gradual steps are centred at 215 and 186 K and are separated by an inflection point at about 201 K, at which 50 % of the complex molecules undergo a spin transition. The two steps are related to the existence of two crystallographically inequivalent metal sites, as confirmed by the structural and Mössbauer studies. The crystal structure was resolved at 293 K (HS form) and 130 K (LS form). Both spin-state structures belong to the triclinic P1 space group (Z=2). The complex assumes a linear chain structure, in which the active iron(II) sites are linked to each other by anionic dicyanamide ligands acting as chemical bridges. The Fe-Fe distances through the dca ligand are 8.119(1) and 7.835(1) A in the high-spin and low-spin structures, respectively. The polymeric chains extend along a (1, 0, -1) axis and are packed in sheets, between which the perchlorate anions and methanol molecules are inserted. The complex molecules are linked together by pi-stacking interactions and H-bonding between the H-donor aqin ligands and the perchlorate ions. These structural features provide a basis for cooperative interactions in the crystal lattice. Analysis of the two-step spin-crossover character in this compound suggests that covalent interactions through the spacer ligand do not provide the main mechanism of cooperativity. PMID:17955555

Genre, Caroline; Jeanneau, Erwann; Bousseksou, Azzedine; Luneau, Dominique; Borshch, Serguei A; Matouzenko, Galina S

2008-01-01

397

Catalyst-site-controlled coordination polymerization of polar vinyl monomers to highly syndiotactic polymers.  

PubMed

This contribution reports a combined synthetic, kinetic, mechanistic, and theoretical/computational study of the recently discovered catalyst-site-controlled coordination polymerization of polar vinyl monomers [such as methyl methacrylate (MMA) and N,N-dimethylacrylamide (DMAA)] into highly syndiotactic polymers. Among the 12 C(s)-ligated ansa-cyclopentadienyl (Cp)-R(2)E(C,Si)-fluorenyl (Flu) group 4 metallocene catalyst systems examined-which varied in metal center, anion structure, bridging atom and substituents, and ligand substitution pattern-cationic ansa-metallocene ester enolate catalyst 6(+)[B(C(6)F(5))(4)](-), derived from the activation of the precatalyst [Ph(2)C(Cp)(2,7-(t)Bu(2)-Flu)]Zr[OC(O(i)Pr)=CMe(2)](2) with [Ph(3)C][B(C(6)F(5))(4)], stood out as the best catalyst in all aspects of the MMA polymerization at room temperature, including the highest activity (1554 h(-1) TOF), efficiency (98% I*), syndiotacticity (94% rr), and control (predicted number-average molecular weight and 1.14 molecular weight distribution). Kinetic and mechanistic results are consistent with a catalyst-site-controlled, monometallic coordination-addition mechanism, involving fast intramolecular addition within the catalyst-monomer complex leading to the resting eight-membered ester enolate chelate, followed by the rate-limiting ring-opening of the chelate to regenerate the active species. This work has also uncovered several unique features of this polymerization system that are in marked contrast to the propylene polymerization by analogous C(s)-ligated cationic alkyl catalysts: a constant syndiotacticity of PMMA produced over a wide polymerization temperature range (i.e., from 0 degrees C, 94% rr to 25 degrees C, 94% rr to 50 degrees C, 93% rr); insensitivity of its high activity, degree of control, and stereoselectivity to solvent polarity and structure of weakly coordinating anions; and deviation from a pure site-control mechanism at high [MMA]/[catalyst] ratios. Computational results provide theoretical support for the proposed monomer-assisted, catalyst-site epimerization, after an enantiofacial mistake, to a thermodynamically more stable resting state, which accounts for the observed higher than expected [mr] contents based on a pure site-controlled mechanism. DFT calculations rationalize why the Ph(2)C< bridged catalyst 6 exhibits higher stereoselectivity than other catalysts with the Me(2)C< or Me(2)Si< bridge: the bridge rigidity pushes the eta(3)-bound Flu ligand closer to the growing chain and the monomer, thereby increasing DeltaE(stereo) between the competing transition states for the addition of a monomer molecule to the opposite (correct and wrong) enantiofaces of the enolate growing chain. The relative polymerization activity of this catalyst series is shown to correlate with the relative energetics of the back-biting of the penultimate unit and ion-pair formation. PMID:20121281

Zhang, Yuetao; Ning, Yalan; Caporaso, Lucia; Cavallo, Luigi; Chen, Eugene Y-X

2010-03-01

398

A new three-dimensional coordination polymer of Sr(II) based on dipicolinic acid, with different coordination environments for Sr(II.).  

PubMed

A three-dimensional coordination polymer of Sr(II) based on dipicolinic acid (pydcH2) has been synthesized and characterized, namely poly[[diaquabis(?3-6-carboxypyridine-2-carboxylato)bis(?4-pyridine-2,6-dicarboxylato)tristrontium(II)] dihydrate], {[Sr3(C7H3NO4)2(C7H4NO4)2(H2O)2]·2H2O}n. The asymmetric unit consists of two unique Sr(II) centres (one of them situated on an inversion centre), two independent pydc(2-) ligands, and one coordinated and one uncoordinated water molecule. The two independent Sr(II) cations are surrounded by water and dipicolinate molecules in distorted square-antiprism and distorted tricapped trigonal prismatic geometries. The dipicolinate ligands adopt ?3- and ?4-bridging modes, linking the alkaline earth metal centres into a three-dimensional coordination framework. One dipicolinate ligand is doubly deprotonated, while the other is singly deprotonated. PMID:24898968

Soleimannejad, Janet; Derikvand, Zohreh; Koleiae, Farzaneh

2014-06-15

399

Bismuth 2,6-pyridinedicarboxylates: assembly of molecular units into coordination polymers, CO2 sorption and photoluminescence.  

PubMed

Six inorganic-organic bismuth 2,6-pyridinedicarboxylate (pdc) compounds, [Bi(2,6-pdc)(3)]·3(dma), 1, [Bi(2,6-pdc)(3)]·3(dma)·2(H(2)O), 2, [Bi(2,6-pdc)(2)(dmf)]·(dma), 3, Bi(2,6-pdc)(2,6-pdcme)(MeOH), 4, [LiBi(2,6-pdc)(3)(H(2)O)]·2(dma), 5, and Li(5)Bi(2,6-pdc)(4)(H(2)O)(2), 6 (where dma = dimethyl ammonium cation, dmf = dimethylformamide and 2,6-pdcme = 6-methyl-oxycarbonyl pyridine 2-carboxylate) have been synthesized under solvothermal conditions and their structures determined by single crystal X-ray diffraction. Compounds 1-4 have molecular structures whereas compounds 5 and 6 form one- and three-dimensional frameworks, respectively. Compounds 1 and 2, both having similar monomeric bismuth coordination units, which are connected non-covalently into a (4,4)-connected square lattice by H-bonding interactions through dma cations. Compounds 3 and 4, both have a similar dimeric bismuth coordination unit. In 3, the dimers are connected into a one-dimensional chain by H-bonding interactions through dma cations. In the partially esterified and neutral 4, there was no such H-bonding interactions due to the absence of any dma cations. Compounds 5 and 6 have a similar monomeric bismuth coordination unit to that seen in 1 and 2. In 5, the monomers are connected through lithium cations into one-dimensional chains, which further interact non-covalently by H-bonding interactions through dma cations. In the lithium-rich 6, the monomers are connected by the lithium cations and 2,6-pdc anions into a three dimensional structure with intramolecular H-bonding interactions involving the water molecules. The non-porous 5 and 6 exhibit a reasonable amount of H(2) and CO(2) sorptions, respectively. Tb(3+)- and Eu(3+)-doped and co-doped 4 and 5 emit characteristic sensitized green/red/yellow-orange luminescence. PMID:22378230

Thirumurugan, A; Li, Wei; Cheetham, Anthony K

2012-04-14

400

AC calorimetry of Quasi-one-dimensional materials  

NASA Astrophysics Data System (ADS)

There has been continuing interest in quasi-one-dimensional materials for decades. Their one-dimensional nature gives rise to many unusual properties such as spin-density waves, charge-density waves, spin-Peierls transitions, glassy behavior, and large fluctuation effects. We study these phase transitions by measuring resistance, specific heat, and Young's moduli, among other properties. We have measured the specific heat of small (˜1 mg) single crystalline flakes of alpha'-NaV2O5. The size of the peak (Deltacp ˜ R) is more than an order of magnitude greater than the value estimated from mean-field theory. The specific heat and Young's modulus anomalies are very large and sample dependent. Subsequent work has shown that NaV2O5 does not go through a spin-Peierls transition as was first thought. It is generally believed that this is a charge order phase transition, with a transformation into a spin gap singlet state We have measured the specific heat of single crystals of TSeF-TCNQ. Anomalies are observed at Ta = 28K and Tb = 33K, indicating that there are two phase transitions, presumably reflecting the separate condensation of the charge-density wave on the TSeF and TCNQ conducting chains. We built an ac Joule calorimeter to measure the specific heats of materials from 1K to 10K. Pumping on liquid helium allowed us to operate at any temperatures between 1K and 4.2K. Oscillating power was applied to the sample with a thin film resistor attached directly to the sample. The magnitude of the oscillating temperature is inversely proportional to the heat capacity when certain experimental conditions are met. We have searched for dynamic thermal effects in (TMTSF)2PF 6 by measuring its specific heat with ac calorimetry. Near its spin-density wave transition (Tc = 12K), the magnitude of the specific heat is the same as that measured in quasi static measurements, indication that there are no kinetic contributions to the specific heat at these temperatures. No anomalies are observed in a pellet of (TMTSF)2PF6 mixed with KBr at Tc or the expected "spin-density wave glass" transition (Tg ˜ 3.5K), suggesting that residual disorder in the pellet freezes in a glassy state at Tc.

Powell, David Kennedy

401

An adaptive grid algorithm for one-dimensional nonlinear equations  

NASA Technical Reports Server (NTRS)

Richards' equation, which models the flow of liquid through unsaturated porous media, is highly nonlinear and difficult to solve. Step gradients in the field variables require the use of fine grids and small time step sizes. The numerical instabilities caused by the nonlinearities often require the use of iterative methods such as Picard or Newton interation. These difficulties result in large CPU requirements in solving Richards equation. With this in mind, adaptive and multigrid methods are investigated for use with nonlinear equations such as Richards' equation. Attention is focused on one-dimensional transient problems. To investigate the use of multigrid and adaptive grid methods, a series of problems are studied. First, a multigrid program is developed and used to solve an ordinary differential equation, demonstrating the efficiency with which low and high frequency errors are smoothed out. The multigrid algorithm and an adaptive grid algorithm is used to solve one-dimensional transient partial differential equations, such as the diffusive and convective-diffusion equations. The performance of these programs are compared to that of the Gauss-Seidel and tridiagonal methods. The adaptive and multigrid schemes outperformed the Gauss-Seidel algorithm, but were not as fast as the tridiagonal method. The adaptive grid scheme solved the problems slightly faster than the multigrid method. To solve nonlinear problems, Picard iterations are introduced into the adaptive grid and tridiagonal methods. Burgers' equation is used as a test problem for the two algorithms. Both methods obtain solutions of comparable accuracy for similar time increments. For the Burgers' equation, the adaptive grid method finds the solution approximately three times faster than the tridiagonal method. Finally, both schemes are used to solve the water content formulation of the Richards' equation. For this problem, the adaptive grid method obtains a more accurate solution in fewer work units and less computation time than required by the tridiagonal method. The performance of the adaptive grid method tends to degrade as the solution process proceeds in time, but still remains faster than the tridiagonal scheme.

Gutierrez, William E.; Hills, Richard G.

1990-01-01

402

Flexible coordination polymers composed of luminescent ruthenium(II) metalloligands: importance of the position of the coordination site in metalloligands.  

PubMed

Coordination polymerization reactions between ruthenium(II) metalloligands [Ru(n,n'-dcbpy)](4-) ([nRu]; n = 4, 5; n,n'-dcbpy = n,n'-dicarboxy-2,2'-bipyridine) and several divalent metal salts in basic aqueous solutions afforded porous luminescent complexes formulated as [Mg(H2O)6]{[Mg(H2O)3][4Ru]·4H2O} (Mg2[4Ru]·13H2O), [Mg2(H2O)9][5Ru]·10H2O (Mg2[5Ru]·19H2O), {[Sr4(H2O)9][4Ru]2·9H2O} (Sr2[4Ru]·9H2O)2, {[Sr2(H2O)8][5Ru]·6H2O} (Sr2[5Ru]·14H2O), and {[Cd2(H2O)2][5Ru]·10H2O} (Cd2[5Ru]·12H2O). Single-crystal X-ray structural analyses revealed that the divalent metal ions were commonly coordinated by the carboxyl groups of the [nRu] metalloligand, forming porous frameworks with a void fraction varying from 11.4% Mg2[4Ru]·13H2O to 43.9% Cd2[5Ru]·12H2O. M2[4Ru]·nH2O showed a reversible structural transition accompanied by water and methanol vapor adsorption/desorption, while the porous structures of M2[5Ru]·nH2O were irreversibly collapsed by the removal of crystal water. The triplet metal-to-ligand charge-transfer emission energies of M2[4Ru]·nH2O were lower than those of [4Ru] in aqueous solution, whereas those of M2[5Ru]·nH2O were close to those of [5Ru] in aqueous solution. These results suggested that the position of the coordination site in the metalloligand played an important role not only on the structure of the porous framework but also on the structural flexibility involving the guest adsorption/desorption properties. PMID:24558962

Kobayashi, Atsushi; Ohba, Tadashi; Saitoh, Erika; Suzuki, Yui; Noro, Shin-ichiro; Chang, Ho-Chol; Kato, Masako

2014-03-17

403

Synthesis, structures and properties of two metal-organic coordination polymers derived from manganese(??), thiabendazole and polydentate carboxylic acids.  

PubMed

Two novel binuclear Mn(II) metal-organic coordination complexes [Mn2(TBZ)2(CDC)(C2O4)]n (1), {[Mn2(TBZ)2(BDC)(0.5)(BTC)(H2O)2]·ET}n (2), (where TBZ = thiabendazole, H2CDC = trans-1,4-cyclohexanedicarboxylic acid, H2C2O4 = oxalic acid, H3BTC = 1,3,5-benzenetricarboxylic acid, ET = ethanol, H2BDC = 1,4-benzenedicarboxylate) have been hydrothermally synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, electrochemical analysis and single crystal X-ray diffraction. The X-ray structure analysis reveals that 1 is s two-dimensional layer and 2 is s one-dimensional chain. In complex 1, it reveals 2-D layers composed of multi-(bidentate) bridging ligands (CDC and C2O4), and in 2, the coordinated BTC ligands adopt a monodentate mode and with BDC ligands adopt alternately chelating Mn1 and Mn2 bridges into 1-D chains. The 3-D structures of the two complexes are stabilized by ?-? stacking interactions and hydrogen bonds. PMID:24317523

Liang, Peng; Xia, Wen-Xiu; Tian, Wei-Man; Yin, Xian-Hong

2013-01-01

404

A copper(I)/copper(II)-salen coordination polymer as a bimetallic catalyst for three-component Strecker reactions and degradation of organic dyes.  

PubMed

A copper(i)/copper(ii)-salen coordination polymer prepared by solvothermal reactions shows prominent bimetallic catalytic activities towards three-component Strecker reactions and photodegradation of organic dyes under visible-light illumination. PMID:24440923

Hou, Yun-Long; Sun, Raymond Wai-Yin; Zhou, Xiao-Ping; Wang, Jun-Hao; Li, Dan

2014-03-01

405

Aromatic carboxylate effect on dimensionality of three bis(benzimidazole)-based cobalt(II) coordination polymers: Syntheses, structures and properties  

NASA Astrophysics Data System (ADS)

Three new metal-organic coordination polymers [Co(4-bbc)2(bbbm)] (1), [Co(3,5-pdc)(bbbm)]·2H2O (2) and [Co(1,4-ndc)(bbbm)] (3) (4-Hbbc=4-bromobenzoic acid, 3,5-H2pdc=3,5-pyridinedicarboxylic acid, 1,4-H2ndc=1,4-naphthalenedicarboxylic acid and bbbm=1,1-(1,4-butanediyl)bis-1H-benzimidazole) were hydrothermally synthesized and structurally characterized. Polymer 1 is a 1D chain formed by the bbbm ligands and CoII ions. Polymer 2 exhibits a 2D network with a (3·4·5)(32·4·5·62·74) topology. Polymer 3 possesses a 3D three-fold interpenetrating framework. The versatile structures of title polymers indicate that the aromatic carboxylates have an important influence on the dimensionality of 1-3. Moreover, the thermal stability, electrochemical and luminescent properties of 1-3 were investigated.

Zhang, Ju-Wen; Gong, Chun-Hua; Hou, Li-Li; Tian, Ai-Xiang; Wang, Xiu-Li

2013-09-01

406

Fabrication of one-dimensional organic nanomaterials and their optoelectronic applications.  

PubMed

This paper reviews the recent research and development of one-dimensional (1D) organic nanomaterials synthesized from organic semiconductors or conducting polymers and their applications to optoelectronics. We introduce synthetic methodologies for the fabrication of 1D single-crystalline organic nanomaterials and 1D multi-component organic nanostructures, and discuss their optical and electrical properties. In addition, their versatile applications in optoelectronics are highlighted. The fabrication of highly crystalline organic nanomaterials combined with their integration into nanoelectronic devices is recognized as one of the most promising strategies to enhance charge transport properties and achieve device miniaturization. In the last part of this review, we discuss the challenges and the perspectives of organic nanomaterials for applications in the next generation soft electronics, in terms of fabrication, processing, device integration, and investigation on the fundamental mechanisms governing the charge transport behaviors of these advanced materials. PMID:24749426

Yu, Hojeong; Kim, Dong Yeong; Lee, Kyung Jin; Oh, Joon Hak

2014-02-01

407

Theory of one-dimensional solitons, polarons, and multipolarons: An alternative formulation  

NASA Astrophysics Data System (ADS)

We develop an alternative formulation of the theory of solitons, polarons, and multipolarons in quasi-one-dimensional degenerate and nondegenerate conducting polymers, starting from the continuum Hamiltonian introduced by Brazovskii and Kirova. Based on a convenient real-space representation of the electron Green function in one dimension, we present a simple method of calculating the Green function and the density of states in the presence of a single soliton or polaron defect, through which we derive exact expressions for the soliton, polaron, and multipolaron excitation energies and the self-consistent gap functions for an arbitrary value of the electron-phonon coupling constant. We apply our results to cis-polyacetylene.

Kim, Kihong; Lee, Dong-Hun

2000-04-01

408

Radiative transfer in one-dimensional inhomogeneous atmospheres  

NASA Astrophysics Data System (ADS)

We use Ambartsumian's method of addition of layers to show that various problems, including the standard ones, of radiation transfer in a plane-parallel inhomogeneous atmosphere may be reduced to the solution of the Cauchy problems for linear differential equations. This allows avoiding the known difficulties arising in solving the boundary-value problems to which the classical approach leads. For the purpose of exposition, the paper deals with the simplest one-dimensional problem of multiple scattering for an atmosphere of finite optical thickness. The idea of the approach is that we start with determining the reflection and transmission coefficients of an atmosphere by solving the initial-value problem for a set of linear differential equations of the first order. After that the internal radiation field is found immediately without solving any new equation. The approach is applied to several classical problems of astrophysical interest. In particular, we evaluate the mean number of scatterings undergone by different types of photons. The transfer of radiation in an atmosphere with arbitrarily distributed internal sources is considered. Analytical solutions for these problems are obtained. Simple recursion formulas are derived to find the radiation intensity emitted by a multicomponent atmosphere. The problem of multiple scattering of radiation with partial redistribution over frequencies is discussed to demonstrate the generalization of the approach to the matrix case. The results of numerical calculations are given. All appendices are only available in electronic form at http://www.edpsciences.org

Nikoghossian, A. G.

2004-08-01

409

Characterization of Thermal Transport in One-dimensional Solid Materials  

PubMed Central

The TET (transient electro-thermal) technique is an effective approach developed to measure the thermal diffusivity of solid materials, including conductive, semi-conductive or nonconductive one-dimensional structures. This technique broadens the measurement scope of materials (conductive and nonconductive) and improves the accuracy and stability. If the sample (especially biomaterials, such as human head hair, spider silk, and silkworm silk) is not conductive, it will be coated with a gold layer to make it electronically conductive. The effect of parasitic conduction and radiative losses on the thermal diffusivity can be subtracted during data processing. Then the real thermal conductivity can be calculated with the given value of volume-based specific heat (?cp), which can be obtained from calibration, noncontact photo-thermal technique or measuring the density and specific heat separately. In this work, human head hair samples are used to show how to set up the experiment, process the experimental data, and subtract the effect of parasitic conduction and radiative losses.

Liu, Guoqing; Lin, Huan; Tang, Xiaoduan; Bergler, Kevin; Wang, Xinwei

2014-01-01

410

Geometrically induced nonlinear dynamics in one-dimensional lattices  

NASA Astrophysics Data System (ADS)

We present a lattice model consisting of a single one-dimensional chain, where the masses are interconnected by linear springs and allowed to move in a horizontal direction only, as in a monorail. In the transverse direction each mass is also attached to two other linear springs, one on each side of the mass. The ends of these springs are kept at fixed positions. The nonlinearity in the model arises from the geometric constraints imposed on the motion of the masses, as well as from the configuration of the springs, where in the transverse direction the springs are either in the extended or compressed state depending on the position of the masses. Under these conditions we show that solitary waves are present in the system. In the long wavelength limit an analytic solution for these nonlinear waves is found. Numerical integrations of the equations of motion in the full system are also performed to analyze the conditions for the existence and stability of the nonlinear waves.

Hamilton, Merle D.; de Alcantara Bonfim, O. F.

2006-03-01

411

Nonlinear energy transport in one-dimensional lattices  

NASA Astrophysics Data System (ADS)

We present a simple lattice model consisting of a one-dimensional chain, where the masses are interconnected by linear springs and allowed to move in the horizontal direction only, as in a monorail. In the transverse direction each mass is also attached to two other springs, one on each side of the mass. The ends of these springs are kept at fixed positions. The nonlinearity in the model arises from the geometric constraints imposed on the motion of the masses, as well as from the configuration of the springs. In the transverse directions the springs are either in the extended or compressed state depending on the position of the mass. Under these conditions we show that solitary waves are present in the system. In the long wavelength limit an analytical solution for these nonlinear waves is found. Numeric integrations of the equations of motion in the full system are also performed to analyze the conditions for the existence and stability of the nonlinear waves. Nonlinear supratransmission is examined and shown to exist in the model and an explanation of its mechanism is presented.

Vuppuluri, P.; Hamilton, M.; de Alcantara Bonfim, O. F.

2007-03-01

412

Correlation effects in quasi-one-dimensional quantum wires  

NASA Astrophysics Data System (ADS)

We explore the role of electron correlation in quasi-one-dimensional quantum wires as the range of the interaction potential is changed and their thickness is varied by performing exact quantum Monte Carlo simulations at various electronic densities. In the case of unscreened interactions with a long-range 1/x tail there is a crossover from a liquid to a quasi-Wigner crystal state as the density decreases. When this interaction is screened, quasi-long-range order is prevented from forming, although a significant correlation with 4kF periodicity is still present at low densities. At even lower electron concentration, exchange is suppressed and the electrons behave like spinless fermions. Finally, we study the effect of electron correlations in the double quantum wire experiment [Steinberg , Phys. Rev. B 73, 113307 (2006)] by introducing an accurate model for the screening in the experiment and explicitly including the finite length of the system in our simulations. We find that decreasing the electron density continuously drives the system from a liquid to a state with quite strong 4kF correlations. This crossover takes place around 22?m-1 , near the density where the electron localization occurs in the experiment. The charge and spin velocities are also in good agreement with the experimental findings in the proximity of the crossover. We argue that correlation effects play an important role at the onset of the localization transition.

Shulenburger, Luke; Casula, Michele; Senatore, Gaetano; Martin, Richard M.

2008-10-01

413

One-dimensional model of vapor-dominated geothermal systems  

NASA Astrophysics Data System (ADS)

A one-dimensional model of vapor-dominated geothermal systems in the natural state is developed in order to study the ranges of the heat and mass transport and flow resistance at which a system is capable of existing in the vapor-dominated state. The model consists of a near-surface condensate layer lying above a two-phase counterflow region with rising steam and descending water in a porous saturated medium. Examination of models with condensate layers several hundred meters thick and reservoir temperatures near 513 K, characteristic of real systems, reveals them to have net mass flow rate/thermal conductivity ratios less than about 2.5 x 10 to the -7th K sec-squared/cu m and permeability/thermal conductivity ratios greater than 4.5 x 10 to the -17th m sec-cubed K/kg. Application of the model to the temperature and pressure data for the main reservoir of the Kawah Kamojang geothermal system in West Java indicates a permeability/thermal conductivity ratio between 10 to the -15th and 10 to the -14th m sec-cubed K/kg, or a permeability between 4 and 40 mdarcy for a thermal conductivity of 4 J/m per sec per K. Results also require the existence of a lower permeability cap overlying the higher permeability main reservoir in order to stabilize the water layer above the steam region.

Straus, J. M.; Schubert, G.

1981-10-01

414

Directed assembly of one-dimensional functional nanostructures  

NASA Astrophysics Data System (ADS)

One-dimensional (1D) nanostructures have unique electronic, optical and mechanical properties that have attracted intense interest over the past two decades. Single wall carbon nanotubes (SWNTs) and semiconducting nanorods have long been recognized as potential candidates for future nanoelectronic applications. The small size and the fact that these nanostructures are synthesized either at high temperatures or in solution make it difficult to organize them in complex architectures, a key requirement for their exploitation. As a step toward this goal, we are developing approaches leading to the controlled and ordered arrangement of nanoobjects on lithographically patterned, chemically (or biochemically) functionalized surfaces. One approach consists in patterning metallic nanodots that serve as anchors by selective functionalization with single stranded DNA (ssDNA) or with other chemical moieties. End functionalized nanostructures are attached to the dots through DNA hybridization or through a covalent bond. A second approach consists in patterning hydrophilic regions on hydrophobic substrates. Ion-complexed nanostuctures selectively bind to the hydrophilic pattern.

Penzo, Erika; Palma, Matteo; Wang, Risheng; Wind, Shalom J.

2013-03-01

415

Fractal spectra in generalized Fibonacci one-dimensional magnonic quasicrystals  

NASA Astrophysics Data System (ADS)

In this work we carry out a theoretical analysis of the spectra of magnons in quasiperiodic magnonic crystals arranged in accordance with generalized Fibonacci sequences in the exchange regime, by using a model based on a transfer-matrix method together random-phase approximation (RPA). The generalized Fibonacci sequences are characterized by an irrational parameter ?(p,q), which rules the physical properties of the system. We discussed the magnonic fractal spectra for first three generalizations, i.e., silver, bronze and nickel mean. By varying the generation number, we have found that the fragmentation process of allowed bands makes possible the emergence of new allowed magnonic bulk bands in spectra regions that were magnonic band gaps before, such as which occurs in doped semiconductor devices. This interesting property arises in one-dimensional magnonic quasicrystals fabricated in accordance to quasiperiodic sequences, without the need to introduce some deferent atomic layer or defect in the system. We also make a qualitative and quantitative investigations on these magnonic spectra by analyzing the distribution and magnitude of allowed bulk bands in function of the generalized Fibonacci number Fn and as well as how they scale as a function of the number of generations of the sequences, respectively.

Costa, C. H. O.; Vasconcelos, M. S.; Barbosa, P. H. R.; Barbosa Filho, F. F.

2012-07-01

416

Ultrafast Phase Control in One-Dimensional Correlated Electron Systems  

NASA Astrophysics Data System (ADS)

One-dimensional (1D) correlated electron systems are good targets for the exploration of photoinduced phase transitions (PIPTs). This is because photocarrier generations and/or charge transfer (CT) excitations by lights can stimulate instabilities inherent to the 1D nature of electronic states through strong electron-electron interactions and electron(spin)-lattice interactions. In this paper, we review the ultrafast dynamics of three typical PIPTs observed in 1D correlated electron systems: 1) a photoinduced transition from a Mott insulator to a metal in a halogen-bridged Ni-chain compound, [Ni(chxn)2Br]Br2 (chxn = cyclohexanediamine); 2) a photoinduced melting of a spin-Peierls phase in an organic CT compound, K-tetracyanoquinodimethane (TCNQ); 3) a photoinduced transition between neutral (N) and ionic (I) states in an organic CT compound, tetrathiafulvalene- p-chloranil (TTF-CA). The primary dynamics of these PIPTs are discussed on the basis of the results of femtosecond pump-probe spectroscopy.

Iwai, Shinichiro; Okamoto, Hiroshi

2006-01-01

417

One-dimensional flows of an imperfect diatomic gas  

NASA Technical Reports Server (NTRS)

With the assumptions that Berthelot's equation of state accounts for molecular size and intermolecular force effects, and that changes in the vibrational heat capacities are given by a Planck term, expressions are developed for analyzing one-dimensional flows of a diatomic gas. The special cases of flow through normal and oblique shocks in free air at sea level are investigated. It is found that up to a Mach number 10 pressure ratio across a normal shock differs by less than 6 percent from its ideal gas value; whereas at Mach numbers above 4 the temperature rise is considerable below and hence the density rise is well above that predicted assuming ideal gas behavior. It is further shown that only the caloric imperfection in air has an appreciable effect on the pressures developed in the shock process considered. The effects of gaseous imperfections on oblique shock-flows are studied from the standpoint of their influence on the life and pressure drag of a flat plate operating at Mach numbers of 10 and 20. The influence is found to be small. (author)

1959-01-01

418

Controllable acoustic rectification in one-dimensional piezoelectric composite plates  

NASA Astrophysics Data System (ADS)

Theoretical studies are presented for the band structures and power transmission spectra for both symmetric and asymmetric Lamb wave modes in a one-dimensional piezoelectric composite plate consisting of piezoelectric ceramics placed periodically in epoxy by the plane wave expansion method and the harmonic response analysis method, respectively. The one-way transmission, two-way transmission, and two-way forbidden models of acoustic rectification for Lamb waves can be established in specific frequency ranges by introducing corresponding modes conversion and selection mechanisms, and the steady-state displacement fields of these models are also calculated for the proposed plate. The numerical results show that the power extinction ratio for one-way transmission model is up to 104. The piezoelectric composite plate can be switched between these models rapidly and efficiently only by applying the open-circuit and short-circuit electric boundary conditions antisymmetrically or symmetrically on the piezoelectric ceramic unit's boundaries instead of changing any geometrical structure, and the composite plate's architecture structure is also simple enough for the on-chip integration in the engineering field.

Zou, Xin-Ye; Liang, Bin; Yuan, Ying; Zhu, Xue-Feng; Cheng, Jian-Chun

2013-10-01

419

Dipolar gases in two coupled one-dimensional lattices  

NASA Astrophysics Data System (ADS)

We consider dipolar bosons in two tubes of one-dimensional lattices, where the boson filling fraction is the same in each tube and the dipoles are aligned to be maximally repulsive. In the classical limit of zero inter-site hopping, the bosons arrange themselves into an ordered crystal for any rational filling fraction, forming a complete devil's staircase like in the single tube case [1]. When we turn on hopping within each tube, we obtain a competition between the crystalline Mott phases and a superfluid of defects or solitons. However, in contrast to the single tube case [2], we find that solitons in different tubes can bind into pairs for certain topologies of the filling fraction. This provides an intriguing example of pairing that is purely driven by correlations close to a Mott insulator.[4pt] [1] P. Bak and P. Bruinsma, Phys. Rev. Lett. 49, 249 (1982)[0pt] [2] F. J. Burnell, M. M. Parish, N. R. Cooper and S. L. Sondhi, Phys. Rev. B, 80, 174519 (2009)

Bauer, Marianne; Parish, Meera

2012-02-01

420

Interaction effects in a one-dimensional constriction  

NASA Astrophysics Data System (ADS)

We have investigated the transport properties of one-dimensional (1D) constrictions defined by split-gates in high quality GaAs/AlxGa1-xAs heterostructures. In addition to the usual quantized conductance plateaus, the equilibrium conductance shows a structure close to 0.7(2e2/h), and in consolidating our previous work [K. J. Thomas et al., Phys. Rev. Lett. 77, 135 (1996)] this 0.7 structure has been investigated in a wide range of samples as a function of temperature, carrier density, in-plane magnetic field B||, and source-drain voltage Vsd. We show that the 0.7 structure is not due to transmission or resonance effects, nor does it arise from the asymmetry of the heterojunction in the growth direction. All the 1D subbands show Zeeman splitting at high B||, and in the wide channel limit the g factor is \\|g\\|~0.4, close to that of bulk GaAs. As the channel is progressively narrowed we measure an exchange-enhanced g factor. The measurements establish that the 0.7 structure is related to spin, and that electron-electron interactions become important for the last few conducting 1D subbands.

Thomas, K. J.; Nicholls, J. T.; Appleyard, N. J.; Simmons, M. Y.; Pepper, M.; Mace, D. R.; Tribe, W. R.; Ritchie, D. A.

1998-08-01

421

Defect modes in one-dimensional granular crystals  

NASA Astrophysics Data System (ADS)

We study the vibrational spectra of one-dimensional statically compressed granular crystals (arrays of elastic particles in contact) containing light-mass defects. We focus on the prototypical settings of one or two spherical defects (particles of smaller radii) interspersed in a chain of larger uniform spherical particles. We present a systematic measurement, using continuous noise, of the near-linear frequency spectrum within the spatial vicinity of the defect(s). Using this technique, we identify the frequencies of the localized defect modes as a function of the defect size and the position of the defects relative to each other. We also compare the experimentally determined frequencies with those obtained by numerical eigenanalysis and by analytical expressions based on few-site considerations. These approximate analytical expressions, based on normal-mode analysis, are found to be in excellent agreement with numerics for a wide range of mass ratios. We also observe that the experimentally measured frequencies of the localized defect modes are uniformly upshifted, compared to the numerically and theoretically predicted values.

Man, Y.; Boechler, N.; Theocharis, G.; Kevrekidis, P. G.; Daraio, C.

2012-03-01

422

One-dimensional quantum walk with a moving boundary  

SciTech Connect

Quantum walks are interesting models with potential applications to quantum algorithms and physical processes such as photosynthesis. In this paper, we study two models of one-dimensional quantum walks, namely, quantum walks with a moving absorbing wall and quantum walks with one stationary and one moving absorbing wall. For the former, we calculate numerically the survival probability, the rate of change of average position, and the rate of change of standard deviation of the particle's position in the long time limit for different wall velocities. Moreover, we also study the asymptotic behavior and the dependence of the survival probability on the initial particle's state. While for the latter, we compute the absorption probability of the right stationary wall for different velocities and initial positions of the left wall boundary. The results for these two models are compared with those obtained for the classical model. The difference between the results obtained for the quantum and classical models can be attributed to the difference in the probability distributions.

Kwek, Leong Chuan [Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543 (Singapore); National Institute of Education and Institute of Advanced Studies, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616 (Singapore); Setiawan [Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore)

2011-09-15

423

Digital noise generators using one-dimensional chaotic maps  

NASA Astrophysics Data System (ADS)

This work shows how to improve the statistical distribution of signals produced by digital noise generators designed with one-dimensional (1-D) chaotic maps. It also shows that in a digital electronic design the piecewise linear chaotic maps (PWLCM) should be considered because they do not have stability islands in its chaotic behavior region, as it occurs in the case of the logistic map, which is commonly used to build noise generators. The design and implementation problems of the digital noise generators are analyzed and a solution is proposed. This solution relates the output of PWLCM, usually defined in the real numbers' domain, with a codebook of S elements, previously defined. The proposed solution scheme produces digital noise signals with a statistical distribution close to a uniform distribution. Finally, this work shows that it is possible to have control over the statistical distribution of the noise signal by selecting the control parameter of the PWLCM and using, as a design criterion, the bifurcation diagram.

Martínez-Íonthe, J. A.; Palacios-Luengas, L.; Cruz-Irisson, M.; Díaz Méndez, J. A.; Vazquez Medina, R.

2014-05-01

424

Control of water molecule aggregations in copper 1,4-cyclohexanedicarboxylate coordination polymers containing pyridyl-piperazine type ligands  

NASA Astrophysics Data System (ADS)

A series of layered divalent copper coordination polymers containing 1,4-cyclohexanedicarboxylate and long-spanning pyridyl-piperazine type ligands exhibits greatly different co-crystallized water molecule aggregations depending on the specific ligands used. Both [Cu(t-14cdc)(4-bpmp)]n (1, t-14cdc = trans-1,4-cyclohexanedicarboxylate, 4-bpmp = bis(4-pyridylmethyl)piperazine) and {[Cu(t-14cdc)(4-bpfp)(H2O)2]·6H2O}n (2, 4-bpfp = bis(4-pyridylformyl)piperazine) possess 2D (4,4) coordination polymer grids. However 1 lacks any co-crystallized water and has pinched grid apertures, while 2 manifests infinite water tapes with T6(2)4(2) classification and rectangular grid apertures. {[Cu2(c-14cdc)2(4-bpmp)]·2H2O}n (3, c-14cdc = cis-1,4-cyclohexanedicarboxylate) has [Cu2(c-14cdc)]2 ribbons with paddlewheel dimeric units linked into 2D slabs by 4-bpmp tethers, along with isolated water molecule pairs. In contrast, {[Cu2(c-14cdc)2(4-bpfp)]·10H2O}n (4) shows a very similar underlying coordination polymer topology but entrains unique decameric water molecule clusters. The minor product {[Cu2(c-14cdcH)2(t-1,4-cdc)(4-bpfp)2(H2O)2]·2H2O}n (5) was isolated along with 4; this compound underwent some in situ cis to trans cyclohexane-dicarboxylate ligand isomerization and exhibits a ladder polymer motif.

Qiblawi, Sultan H.; LaDuca, Robert L.

2014-01-01

425

A copper(I) coordination polymer incorporation the corrosion inhibitor 1H-benzotriazole: poly[?3-benzotriazolato-?(3)N(1):N(2):N(3)-copper(I)].  

PubMed

The title complex, [Cu(C6H4N3)]n, was synthesized by the reaction of cupric nitrate, 1H-benzotriazole (BTAH) and aqueous ammonia under hydrothermal conditions. The asymmetric unit contains three crystallographically independent Cu(I) cations and two 1H-benzotriazolate ligands. Two of the Cu(I) cations, one with a linear two-coordinated geometry and one with a four-coordinated tetrahedral geometry, are located on sites with crystallographically imposed twofold symmetry. The third Cu(I) cation, with a planar three-coordinated geometry, is on a general position. Two Cu(I) cations are doubly bridged by two BTA(-) ligands to afford a noncentrosymmetric planar [Cu2(BTA)2] subunit, and two [Cu2(BTA)2] subunits are arranged in an antiparallel manner to form a centrosymmetric [Cu2(BTA)2]2 secondary building unit (SBU). The SBUs are connected in a crosswise manner via the sharing of four-coordinated Cu(I) cations, Cu-N bonding and bridging by two-coordinate Cu(I) cations, resulting in a one-dimensional chain along the c axis. These one-dimensional chains are further linked by C-H...? and weak van der Waals interactions to form a three-dimensional supramolecular architecture. PMID:24898965

Liu, Jian Jun; Li, Zuo Yin; Yuan, Xiong; Wang, Yao; Huang, Chang Cang

2014-06-15

426

Giant negative magnetoresistance in quasi-one-dimensional conductor TPP[Fe(Pc)(CN)2]2: Interplay between local moments and one-dimensional conduction electrons  

Microsoft Academic Search

We have found giant negative magnetoresistance in the one-dimensional conductor TPP[Fe(Pc)(CN)2]2 below 50 K. The reduction of the resistance is larger in the field perpendicular to the one-dimensional axis than parallel to the axis. The magnetic susceptibility shows anisotropic Curie-Weiss behavior. The experimental results suggest the interaction between the one-dimensional electron system and the local moments. The reduction of the

N. Hanasaki; H. Tajima; M. Matsuda; T. Naito; T. Inabe

2000-01-01

427

Rare configuration of tautomeric benzimidazolecarboxylate ligands in cadmium(II) and copper(II) coordination polymers  

NASA Astrophysics Data System (ADS)

Two Cd(HBimc)-based isomers, [Cd(HBimc N)(HBimc T)(H 2O)]·3.5H 2O·EtOH ( 1a·3.5H 2O·EtOH, H 2Bimc=1 H-benzimidazole-5-carboxylic acid) and [Cd(HBimc N)(HBimc T)(H 2O)] ( 1b), and two Cu(HMBimc)-based coordination polymers, [Cu(HMBimc N) 2(H 2O)]·1/2H 2O ( 2·1/2H 2O, H 2MBimc=2-methyl-1 H-benzimidazole-5-carboxylic acid) and [Cu(HMBimc T) 2]·2THF·H 2O ( 3·2THF·H 2O), were self-assembled from Cd(ClO 4) 2·6H 2O/H 2Bimc and Cu(ClO 4) 2·6H 2O/H 2MBimc systems, respectively. Compound 1a adopts a ladder-like chain structure, comprised of a hydrogen-bond-stabilized Cd 2(HBimc N) 2-metallocyclic stair and a 1D straight -(Cd-HBimc T) n- edge, whereas compound 1b exhibits a 2D (4,4)-rhombus layered structure, intercrossed by 1D -(Cd-HBimc N) n- chains and -(Cd-HBimc T) n- chains. Compound 2 shows a 1D double-stranded wave-like chain from two single-stranded wave-like -(Cu-HMBimc N) n- chains and compound 3 adopts a 2D (4,4)-topological layer structure, intercrossed by subunits of 1D -(Cu-HMBimc T) n- chains. Interestingly, a pair of tautomeric HBimc building blocks—normal ( N or HBimc N) and tautomer ( T or HBimc T)—is simultaneously included in the structures of 1a and 1b, whilst the N- and T-configured HMBimc building blocks are present as separate entities in Cu species, 2 and 3, respectively. The existence of only a tautomer ( T) mode of the benzimidazolecarboxylate-based ligand in a Cu(II) network is observed for the first time.

Wu, Jing-Yun; Yang, Ciao-Wei; Chen, Hui-Fang; Jao, Yu-Chen; Huang, Sheng-Ming; Tsai, Chiitang; Tseng, Tien-Wen; Lee, Gene-Hsiang; Peng, Shie-Ming; Lu, Kuang-Lieh

2011-07-01

428

Proton dynamics of two-dimensional oxalate-bridged coordination polymers.  

PubMed

A two-dimensional porous coordination polymer (NH4)2{HOOC(CH2)4COOH}[Zn2(C2O4)3] (abbreviated as (NH4)2(adp)[Zn2(ox)3] (adp = adipic acid, ox = oxalate)), which accommodates water molecules between the [Zn2(ox)3] layers, is highly remarked as a new type of crystalline proton conductor. In order to investigate its phase behavior and the proton conducting mechanism, we have performed adiabatic calorimetry, neutron diffraction, and quasi-elastic neutron scattering experiments on a fully hydrated sample (NH4)2(adp)[Zn2(ox)3]·3H2O with the highest proton conductivity (8 × 10(-3) S cm(-1), 25 °C, 98% RH). Its isostructural derivative K2(adp)[Zn2(ox)3]·3H2O was also measured to investigate the role of ammonium ions. (NH4)2(adp)[Zn2(ox)3]·3H2O and K2(adp)[Zn2(ox)3]·3H2O exhibit higher order transitions at 86 K and 138 K, respectively. From the magnitude of the transition entropy, the former is of an order-disorder type while the latter is of a displacive type. (NH4)2(adp)[Zn2(ox)3]·3H2O has four Debye-type relaxations and K2(adp)[Zn2(ox)3]·3H2O has two similar relaxations above each transition temperature. The two relaxations of (NH4)2(adp)[Zn2(ox)3]·3H2O with very small activation energies (?Ea < 5 kJ mol(-1)) are due to the rotational motions of ammonium ions and play important roles in the proton conduction mechanism. It was also found that the protons in (NH4)2(adp)[Zn2(ox)3]·3H2O are carried through a Grotthuss mechanism. We present a discussion on the proton conducting mechanism based on the present structural and dynamical information. PMID:25019223

Miyatsu, Satoshi; Kofu, Maiko; Nagoe, Atsushi; Yamada, Takeshi; Sadakiyo, Masaaki; Yamada, Teppei; Kitagawa, Hiroshi; Tyagi, Madhusudan; García Sakai, Victoria; Yamamuro, Osamu

2014-07-23

429

One-dimensional kinematic model of preferred orientation development  

NASA Astrophysics Data System (ADS)

The one-dimensional model to analyse the kinematics of crystallographic preferred orientation of Ribe (1989)is presented and developed further. It is argued that this approach can be applied to rotational deformations where the predominant deformation mechanism is grain boundary sliding. Two contrasting situations are distinguished. The first is where lattice rotations of opposing sense occur and there are orientations for which the rotation rate is zero. In this case a continually intensifying preferred orientation at an orientation with zero rotation rate will result. The second situation is where the rotation of the lattice is in the same sense for all orientations. Initially maxima develop in the orientation of greatest negative divergence in the lattice rotation rate function. A steady-state preferred orientation profile is possible which is the normalised inverse of the function describing lattice rotation rate vs. orientation and the maxima are at the orientations for which the lattice rotation rate is a minimum. The intensity of the preferred orientation is a function of the ratio of the greatest to least lattice rotation rates. The results are applied to a natural mylonite preferred orientation which consists of a c axis maximum in the mylonitic foliation perpendicular to the stretching lineation. It is argued that the crystal lattices rotate about a stably oriented c axis and the profile through the orientation distribution describing the probability of finding particular orientations differing by a rotation about c is inverted to give an estimate of the lattice rotation rate profile. It is found that the lattice rotates slowest when the second-order prism direction a is aligned parallel to the foliation normal and fastest when a is aligned sub-parallel to the stretching lineation.

Casey, Martin; McGrew, Allen J.

1999-03-01

430

One-dimensional itinerant interacting non-Abelian anyons  

NASA Astrophysics Data System (ADS)

We construct models of interacting itinerant non-Abelian anyons moving along one-dimensional chains. We focus on itinerant Ising (Majorana) and Fibonacci anyons, which are, respectively, related to SU(2)2 and SU(2)3 anyons and also, respectively, describe quasiparticles of the Moore-Read and Z3-Read-Rezayi fractional quantum Hall states. Following the derivation of the electronic large-U effective Hubbard model, we derive effective anyonic t-J models for the low-energy sectors. Solving these models by exact diagonalization, we find a fractionalization of the anyons into charge and (neutral) anyonic degrees of freedom—a generalization of spin-charge separation of electrons which occurs in Luttinger liquids. A detailed description of the excitation spectrum can be performed by combining spectra for charge and anyonic sectors. The anyonic sector is that of a squeezed chain of localized interacting anyons and, hence, is described by the same conformal field theory (CFT), with central charge c=1/2 for Ising anyons and c=7/10 or c=4/5 for Fibonacci anyons with antiferromagnetic or ferromagnetic coupling, respectively. The charge sector is the spectrum of a chain of hard-core bosons subject to phase shifts which coincide with the momenta of the combined anyonic eigenstates, revealing a subtle coupling between charge and anyonic excitations at the microscopic level (which we also find to be present in Luttinger liquids), despite the macroscopic fractionalization. The combined central charge extracted from the entanglement entropy between segments of the chain is shown to be 1+c, where c is the central charge of the underlying CFT of the localized anyon (squeezed) chain.

Poilblanc, Didier; Feiguin, Adrian; Troyer, Matthias; Ardonne, Eddy; Bonderson, Parsa

2013-02-01

431

High-Frequency Characteristics of One-Dimensional Carbon Nanostructures  

NASA Astrophysics Data System (ADS)

The ever increasing demand for faster and more reliable chips depends largely on the performance of on-chip interconnects. Over ten years ago, copper became the preferred metal over aluminum as the on-chip interconnects material in the most advanced silicon chip technology. However, as copper interconnects scale down, its resistivity increases exponentially due to the degrading effect of surface scattering and grain-boundary scattering. Currently, the scaled-down copper interconnects suffer from reliability concerns due to electromigration in the sub-30 nm technology regime. In order to keep up with the International Technology Roadmap for Semiconductors (ITRS), copper must be replaced. Because of their superior properties, carbon-based nanostructures are the preferred choice to replace copper in next-generation integrated circuits. The principal objective of this work is to develop a methodology to investigate the high-frequency electrical conduction in one-dimensional carbon nanostructures, in particular, carbon nanofibers (CNFs) as a potential replacement for copper in next-generation on-chips interconnects. This work is divided into four parts. First, a high-frequency test structure with low transmission is designed and fabricated, allowing capacitances less than 1fF to be measured from 0.1 to 50 GHz. Second, S-parameters from 0.1 to 50 GHz are measured for the test structure and for the test structure connected by a CNF. Third, based on this data a frequency-independent parallel-RC network that models the CNF is proposed that matches the measured S-parameters. In this model the capacitance is the only fitting parameter. Finally, an analytical approach is developed that validates the frequency-independent RC -model, whose parameters are obtained directly from measurements without fitting. This simple RC-model takes into account the effect of both the contact impedance between the signal pads and the nanofiber, as well the impedance of the nanofiber.

Madriz Flores, Francisco R.

432

One Dimensional Advancing Solidification Front in the Hydrate System  

NASA Astrophysics Data System (ADS)

We use a simplified one dimensional model to study the advancing solidification front of a methane hydrate system fed by gas from below for a laboratory scale problem. We assume the system is initially fully saturated with water, no long range transport of salt by diffusion or advection, and equal density of hydrate and liquid. We express the velocity of the solidification front as a function of the gas supply rate when hydrate formation is not limited by formation kinetics. When the hydrate formation is only limited by formation kinetics, we express the velocity of the solidification front as a function of the methane consumption rate, which is described by an Arrhenius-type equation. By comparing these two types of advancing solidification fronts, we find that the advance of the solidification front will be limited by hydrate formation kinetics if the gas supply rate is greater than 0.2 kg m-2 hour-1. Our analysis is based on the porosity of 0.4, the permeability of 10-13 m2, the temperature of 5 oC, the pressure of 7 MPa and the salinity of 3.5 wt.%. For the same settings, if the gas supply rate is less than 0.2 kg m-2 hour-1, the advancing of the solidification front will be limited by methane advection. We also compare the velocity of the solidification front with the salt diffusion transport. We find that if the gas supply rate is greater than 0.002 kg m-2 hour-1, the advancing of the solidification front will not be influenced by salt diffusion.

You, K.; Flemings, P. B.; Darnell, K.

2013-12-01

433

Few particles correlation in a one-dimensional quasiperiodic lattice  

NASA Astrophysics Data System (ADS)

During the last two decades, two of the most important discoveries in condensed matter physics have been the discovery of quasicrystals and the discovery of high-Tc ceramic superconductors. These topics have generated a large number of experimental and theoretical studies in the physics of low dimension. They have also modified some of the concepts in solid state physics. For instance, it was believed that the five-fold symmetry was incompatible with a long-range order and it was not expected that ceramic materials with a high-Tc and a short coherence length exhibit superconductivity. Therefore, it is important to revise both the spatial symmetry and the electronic correlation to identify how they affect the physical properties of materials. The study of these subjects is complex since we cannot use the reciprocal space to study quasicrystals and the electronic correlation in many-body systems has not entirely been solved. Even in one-dimensional quasiperiodic structures, the interactions between electrons have often been neglected and only few results have been obtained. In this work, we solved the cases of two and three interacting particles in a Fibonacci lattice using a real-space method, the Green function technique, the renormalized perturbation expansion method and the Hubbard model. For the case of two interacting particles an analytical solution for the pairing phase diagram was obtained using the extended Hubbard Hamiltonian. For the case of three interacting particles the binding energy was numerically calculated. The results present here are compared with those obtained for the periodic and binary lattices.

Suárez, J. R.; Vallejo, E.; Carvajal, E.; Navarro, O.

2005-07-01

434

One-dimensional overdriven detonations with branched-chain kinetics  

NASA Astrophysics Data System (ADS)

The dynamics of time-dependent, planar propagation of gaseous detonations is addressed on the basis of a three-step chemistry model that describes branched-chain processes. Relevant nondimensional parameters are the ratio of the heat release to the thermal enthalpy at the Neumann state, the nondimensional activation energies for the initiation and branching steps, the ratio of the branching time to the initiation time and the ratio of the branching time to the recombination time. The limit of strong overdrive is considered, in which pressure remains constant downstream from the leading shock in the first approximation, and the ratio of specific heats ? is taken to be near unity. A two-term expansion in the strong overdrive factor is introduced, and an integral equation is derived describing the nonlinear dynamics and exhibiting a bifurcation parameter, the reciprocal of the product of (?-1), the nondimensional heat release and the nondimensional branching activation energy, with an acoustic correction. A stability analysis shows that, depending on values of the parameters, either the mode of lowest frequency or a mode of higher frequency may be most unstable. Numerical integrations exhibit different conditions under which oscillations die, low-frequency oscillations prevail, high-frequency oscillations prevail, highly nonlinear oscillations persist, or detonation failure occurs. This type of parametric analysis is feasible because of the relative simplicity of the model, which still is more realistic than a one-step, Arrhenius chemical approximation. In particular, by addressing the limit of slow radical recombination compared with branching, explicit results are derived for the critical value of the bifurcation parameter, involving the ratio of the recombination time to the induction time. The results help to clarify the general nature of one-dimensional detonation instability and provide simplifications that can be employed in efficiently relating gaseous detonation behavior to the true underlying chemistry.

Sánchez, Antonio L.; Carretero, Manuel; Clavin, Paul; Williams, Forman A.

2001-03-01

435

Connecting wave functions at a three-leg junction of one-dimensional channels  

NASA Astrophysics Data System (ADS)

We propose a scheme to connect the wave functions on different one-dimensional branches of a three-leg junction ( Y junction). Our scheme differs from that due to Griffith [Trans. Faraday Soc. 49, 345 (1953)] in the respect that ours can model the difference in the widths of the quasi-one-dimensional channels in different systems. We test our scheme by comparing results from a doubly connected one-dimensional system and a related quasi-one-dimensional system, and we find a good agreement. Therefore our scheme may be useful in the construction of one-dimensional effective models out of (multiply connected) quasi-one-dimensional systems.

Voo, Khee-Kyun; Chen, Shu-Chuan; Tang, Chi-Shung; Chu, Chon-Saar

2006-01-01

436

One-dimensional extended defects in epitaxial graphene with metallic properties  

NASA Astrophysics Data System (ADS)

Extended one dimensional line defects with metallic electronic properties are described. These defects have been formed in epitaxial graphene on Ni(111) surfaces and are the consequence of domain boundaries between graphene-sheets occupying different registry relative to the nickel substrate. The domain boundary forms a reconstructed line defect with a repeat unit of one octagon and a pair of pentagons. All the atoms in the defect are sp^2 hybridized three-fold coordinated carbon and thus do not exhibit any dangling bonds. DFT calculations indicate that these defect lines exhibit similar flat band states at the Fermi-level as zigzag-edge states in nanoribbons. STM-imaging indicates a bright contrast surrounding these defects, which we attribute to the decaying wave function of the defect states and its associated self-doping effect in the surrounding graphene sheet. This makes this extended defect a metallic wire embedded in a perfect graphene lattice.

Lahiri, Jayeeta; Lin, You; Bozkurt, Pinar; Oleynik, Ivan; Batzill, Matthias

2010-03-01

437

Moment-Preserving SN Discretizations for the One-Dimensional Fokker-Planck Equation  

SciTech Connect

The Fokker-Planck equation: (1) Describes the transport and interactions of charged particles, (2) Many small-angle scattering collisions, (3) Asymptotic limit of the Boltzmann equation (Pomraning, 1992), and (4) The Boltzmann collision operator becomes the angular Laplacian. SN angular discretization: (1) Angular flux is collocated at the SN quadrature points, (2) The second-order derivatives in the Laplacian term must be discretized, and (3) Weighted finite-difference method preserves zeroth and first moments (Morel, 1985). Moment-preserving methods: (1) Collocate the Fokker-Planck operator at the SN quadrature points, (2) Develop several related and/or equivalent methods, and (3) Motivated by discretizations for the angular derivative appearing in the transport equation in one-dimensional spherical coordinates.

Warsa, James S. [Los Alamos National Laboratory; Prinja, Anil K. [Los Alamos National Laboratory

2012-06-14

438

Paramagnetic charge-transfer guest–host coordination polymers. Thiophene compounds encapsulated within the channels of the three-dimensional coordination polymers [(R 3 Sn) 3 Fe(CN) 6 ] n , R = Me, n Bu or Ph  

Microsoft Academic Search

Various thiophene compounds have been shown to be encapsulated and partly oxidized within the channels of the three-dimensional (3D) host coordination polymers [(R3Sn)3Fe(CN)6]n (R = Me, n-Bu or Ph) to give guest–host encapsulated systems. The structure and physical properties of these systems were studied by X-ray powder diffraction, i.r., u.v.–vis., e.p.r. spectra and magnetic measurements. Thiophene compounds do not polymerize

Moustafa Sh. Ibrahim; Amal H. Werida; Safaa El-din H. Etaiw

2003-01-01

439

Metallic state in disordered quasi-one-dimensional conductors  

NASA Astrophysics Data System (ADS)

The metallic state in conjugated polymers and single-walled carbon nanotubes is studied by dielectric spectroscopy (8-600 GHz). We have found an intriguing correlation between scattering time (?) and plasma frequency (?p):?~?-1.3p. This relation conflicts with the usually applied models that only consider disorder. Based on the observed parallels with doped semiconductors, we argue that the interchain coupling t? plays a role comparable to the doping level and that the unusual free-carrier dynamics in the metallic state can be explained when including the role of t? in the conventional models.

Martens, H. C.; Reedijk, J. A.; Brom, H. B.; Leeuw, D. M.; Menon, R.

2001-02-01

440

Hydrothermal synthesis, crystal structure, and catalytic potential of a one-dimensional molybdenum oxide/bipyridinedicarboxylate hybrid.  

PubMed

The reaction of MoO3, 2,2'-bipyridine-5,5-dicarboxylic acid (H2bpdc), water, and dimethylformamide in the mole ratio 1:1:1730:130 at 150 °C for 3 days in a rotating Teflon-lined digestion bomb leads to the isolation of the molybdenum oxide/bipyridinedicarboxylate hybrid material (DMA)[MoO3(Hbpdc)]·nH2O (1) (DMA = dimethylammonium). Compound 1 was characterized by scanning electron microscopy, FT-IR and (13)C{(1)H} CP MAS NMR spectroscopies, and elemental and thermogravimetric analyses. The solid state structure of 1 was solved and refined through Rietveld analysis of high resolution synchrotron X-ray powder diffraction data in conjunction with information derived from the above techniques. The material, crystallizing in the noncentrosymmetric monoclinic space group Pc, is composed of an anionic one-dimensional organic-inorganic hybrid polymer, ?(1)[MoO3(Hbpdc)](-), formed by corner-sharing distorted {MoO4N2} octahedra, which cocrystallizes with charge-balancing DMA(+) cations and one water molecule per metal center. In the crystal structure of 1, the close packing of individual anionic polymers, DMA(+) cations, and water molecules is mediated by a series of supramolecular contacts, namely strong (O-H···O, N(+)-H···O(-)) and weak (C-H···O) hydrogen bonding interactions, and ?-? contacts involving adjacent coordinated Hbpdc(-) ligands. The catalytic potential of 1 was investigated in the epoxidation reactions of the bioderived olefins methyl oleate (Ole) and DL-limonene (Lim) using tert-butylhydroperoxide (TBHP) as the oxygen donor and 1,2-dichloroethane (DCE) or (trifluoromethyl)benzene (BTF) as cosolvent, at 55 or 75 °C. Under these conditions, 1 acts as a source of active soluble species, leading to epoxide yields of up to 98% for methyl 9,10-epoxystearate (BTF, 75 °C, 100% conversion of Ole) and 89% for 1,2-epoxy-p-menth-8-ene (DCE, 55 °C, 95% conversion of Lim). Catalytic systems employing the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide as solvent could be effectively recycled. PMID:23531277

Amarante, Tatiana R; Neves, Patrícia; Valente, Anabela A; Paz, Filipe A Almeida; Fitch, Andrew N; Pillinger, Martyn; Gonçalves, Isabel S

2013-04-15