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1

One-dimensional Coordination Polymer as New Precursor for Preparation of Fe 2 O 3 Nanoparticles  

Microsoft Academic Search

A Fe(II) one-dimensional coordination polymer, [Fe(pyterpy)2](SCN)2.MeOH (1), which pyterpy is 4?-(4-Pyridyl)-2,2?:6?,2?-terpyridine, has been synthesized by using branched tube and characterized by\\u000a elemental analysis, X-ray powder diffraction (XRD) and IR spectroscopy. Iron(III) oxide nano-particles were obtained by thermolysis\\u000a of compound 1 in oleic acid (surfactant) at 286C under air atmosphere. The Fe2O3 nano-particles were characterized by XRD and scanning electron microscopy.

Azadeh MehraniAli Morsali; Ali Morsali

2

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]n4H2O (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; Gmez-Garca, Carlos J; Hassanein, Khaled; Verma, Sandeep; Kumar, Jitendra; Zamora, Flix

2013-09-16

3

A one-dimensional copper coordination polymer containing both dicyanamide and 1,10-phenanthroline ligands.  

PubMed

The crystal structure of catena-poly[[[acetato(1,10-phenanthroline-kappa(2)N,N')copper(II)]-micro-dicyanamido-kappa(2)N(1):N(5)] trihydrate], [[Cu(C(2)H(3)O(2))(C(2)N(3))(C(12)H(8)N(2))].3H(2)O](n), consists of a zigzag chain formed by the polymer [Cu(CH(3)COO)(dca)(phen)](n) (phen is 1,10-phenanthroline and dca is dicyanamide), with three water molecules per repeat unit of the polymer. The Cu(II) atom has a slightly distorted square-pyramidal coordination environment consisting of two N atoms of the phen ligand, two nitrile N atoms of different dca ligands, one of them axial, and one O atom of the acetate anion. The compound forms a one-dimensional chain using dca as an end-to-end bridging ligand. Non-covalent interactions, pi-pi stacking and hydrogen bonding mediate the bundling of the polymer chains into a three-dimensional structure, with the water molecules playing an important role in the hydrogen bonding. PMID:14605401

Wu, A-Qing; Cai, Li-Zhen; Chen, Wen-Tong; Guo, Guo-Cong; Huang, Jin-Shun

2003-10-31

4

A novel one-dimensional acentric copper(I) coordination polymer with second-harmonic generation response  

Microsoft Academic Search

The reaction of N,N-(2-pyridyl)(4-pyridylmethyl)amine with [Cu(MeCN)2(PPh3)2]ClO4 in the presence of THF affords a novel one-dimensional copper(I) coordination polymer {[Cu(PPh3)(N,N-(2-pyridyl)(4-pyridylmethyl)amine)](ClO4)}n (1), which crystallizes in an noncentrosymmetric space group and displays strong second-harmonic generation (SHG) response.

Xue-Feng Huang; Yong-Hua Li; Qian Wu; Qiong Ye; Ren-Gen Xiong

2005-01-01

5

Synthesis of designed conductive one-dimensional coordination polymers of Ni(II) with 6-mercaptopurine and 6-thioguanine.  

PubMed

Calculations performed with the goal of designing suitable electrical conductive [M(6-MP)(2)](n) (M = transition metal, 6-MP = 6-mercaptopurinato) one-dimensional coordination polymers suggested that metal ions such as Ni(II) could provide suitable materials. In this work, direct hydrothermal reactions between 6-mercaptopurine (6-MPH) and the analogous 6-thioguanine (6-ThioGH) with NiSO(4).6H(2)O yield the compounds [Ni(6-MP)(2)](n).2nH(2)O [1] and [Ni(6-ThioG)(2)](n).2nH(2)O [2]. The X-ray structures confirm that both compounds present similar structures based on one-dimensional chains in which the deprotonated nucleobases act as the bridging ligands connecting the metal ions by short distances. Electrical measurements at room temperature confirm the conductor character of both coordination polymers. The small differences found in these measurements have been rationalized with the help of density functional theory calculations. Preliminary adsorption studies on surfaces for 1 have allowed characterization of single chains on mica and graphite. The results obtained suggest the potential use of coordination polymers on nanomaterials for molecular electronics. PMID:19624141

Amo-Ochoa, Pilar; Castillo, Oscar; Alexandre, Simone S; Welte, Lorena; de Pablo, Pedro J; Rodrguez-Tapiador, Maria Isabel; Gmez-Herrero, Julio; Zamora, Flix

2009-08-17

6

Syntheses, crystal structures and properties of three one-dimensional coordination polymers generated from flexible bipyridyl ligands  

NASA Astrophysics Data System (ADS)

Three new interesting coordination polymers, [Cu2(?-4,4?-bpp)(OAc)4]n (1), [Cu(?-3,3?-bpp)(SCN)2]n (2) and [Zn(?-4,4?-bpp)2(dca)20.5H2O]n (Hdca=dicyanamide) (3) have been synthesized and structurally characterized. Compounds 1 3 consist of different one-dimensional zigzag chains arising from the different positions of donor atoms (4,4?-bpp or 3,3?-bpp). Thermogravimetric analyses show that the three compounds have very similar thermal behaviors and are stable up to about 270 C. Compound 3 exhibits a blue luminescence with the emission maximum at ca. 457 nm upon excitation at 370 nm which is assigned to the intraligand emission from 4,4?-bpp ligand.

Gong, Ya-Qiong; Wang, Rui-Hu; Zhou, You-Fu; Lin, Zheng-Zhong; Hong, Mao-Chun

2005-09-01

7

Synthesis and crystal structure of a one-dimensional coordination polymer of nickel(II) with 4 ?-(imidazol-1-ylmethyl)benzoate anion  

Microsoft Academic Search

A one-dimensional (1D) coordination polymer, [NiII(imbz)2(H2O)2]n1 [imbz?=4?-(imidazol-1-ylmethyl)benzoate anion] was synthesized by treatment of Ni(CH3COO)24H2O with piperidinium salt of 4?-(imidazol-1-ylmethyl)benzoic acid 2, and characterized by X-ray crystallography. The thermogravimetric analysis (TGA) and magnetic property of the compound 1 are also reported.

Jian Fan; Yan-An Zhang; Taka-aki Okamura; Zhi-Hong Zou; Norikazu Ueyama; Wei-Yin Sun

2001-01-01

8

Two one-dimensional d?-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

2012-02-01

9

Coordination-directed one-dimensional coordination polymers generated from a new oxadiazole bridging ligand and HgX2 (X=Cl, Br and I).  

PubMed

A new 1,3,4-oxadiazole bridging bent organic ligand, 2,5-bis{5-methyl-2-[(4-pyridyl)methoxy]phenyl}-1,3,4-oxadiazole, C(28)H(24)N(4)O(3), L, has been used to create three novel one-dimensional isomorphic coordination polymers, viz. catena-poly[[[dichloridomercury(II)]-?-2,5-bis{5-methyl-2-[(4-pyridyl)methoxy]phenyl}-1,3,4-oxadiazole] methanol monosolvate], {[HgCl(2)(C(28)H(24)N(4)O(3))]CH(3)OH}(n), catena-poly[[[dibromidomercury(II)]-?-2,5-bis{5-methyl-2-[(4-pyridyl)methoxy]phenyl}-1,3,4-oxadiazole] methanol monosolvate], {[HgBr(2)(C(28)H(24)N(4)O(3))]CH(3)OH}(n), and catena-poly[[[diiodidomercury(II)]-?-2,5-bis{5-methyl-2-[(4-pyridyl)methoxy]phenyl}-1,3,4-oxadiazole] methanol monosolvate], {[HgI(2)(C(28)H(24)N(4)O(3))]CH(3)OH}(n). The free L ligand itself adopts a cis conformation, with the two terminal pyridine rings and the central oxadiazole ring almost coplanar [dihedral angles = 5.994 (7) and 9.560 (6)]. In the Hg(II) complexes, however, one of the flexible pyridylmethyl arms of ligand L is markedly bent and helical chains are obtained. The Hg(II) atom lies in a distorted tetrahedral geometry defined by two pyridine N-atom donors from two L ligands and two halide ligands. The helical chains stack together via interchain ?-? interactions that expand the dimensionality of the structure from one to two. The methanol solvent molecules link to the complex polymers through O-HN and O-HO hydrogen bonds. PMID:21633149

Yang, Rui; Ma, Jian Ping; Huang, Ru Qi; Dong, Yu Bin

2011-05-13

10

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), b=6.4907(6), c=13.4007(9), V=1131.37(15)3, 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 Bykgngr

2008-01-01

11

A one-dimensional ABX3-type coordination polymer: catena-poly[benzyltrimethylammonium [tri-?-chlorido-cadmium(II)  

PubMed

The crystal structure of the title novel one-dimensional ABX3-type organic-inorganic hybrid complex {(C10H16N)[CdCl3]}n, (I), consists of benzyltrimethylammonium (Me3BzN(+)) cations and one-dimensional anionic {[Cd(?-Cl)3](-)}? chains. Each Cd(II) centre is hexacoordinated by bridging chloride ligands, giving a slightly distorted octahedral Cd(?-Cl)6 arrangement. The octahedra are linked by two opposite shared faces, giving rise to an almost perfectly linear anionic {[Cd(?-Cl)3](-)}? chain in the a-axis direction. Me3BzN(+) cations located in the inter-chain spaces balance the charge. Noncovalent static attracting forces (Coulombic and van der Waals forces) and nonclassical C-HCl hydrogen-bond interactions stabilize the crystal structure. PMID:23629898

Wu, De-Hong; Jin, Lei

2013-04-11

12

Three-Dimensional Porous Cd(II) Coordination Polymer with Large One-Dimensional Hexagonal Channels: High Pressure CH(4) and H(2) Adsorption Studies.  

PubMed

A new porous and hydrothermally stable three-dimensional (3D) coordination polymer {[Cd(bpydb)]6H(2)O}(n) (1) has been synthesized under solvothermal condition from a new rigid ligand 4,4'-(4,4'-bipyridine-2,6-diyl) dibenzoic acid (H(2)bpydb) and Cd(NO(3))(2)6H(2)O. Single crystal X-ray analysis shows that 1 has a 5-connected 4(4)6(6) vma net with one-dimensional (1D) hexagonal channels filled with water molecules. Integrity of the framework is maintained upon removal of the water molecules by heating to result in a porous framework. Low pressure N(2) and high pressure H(2) and CH(4) sorption studies along with water adsorption studies were performed on this framework. PMID:21142118

Sharma, Manish K; Senkovska, Irena; Kaskel, Stefan; Bharadwaj, Parimal K

2010-12-13

13

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

PubMed

Two new one-dimensional copper(II) polymers with formulae of [Cu(2)(H(2)O)(2)(dmapox)(ipa)(2)](n) (1) and [Cu(2)(H(2)O)(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 structures of 1 and 2 consist of one-dimensional copper(II) coordination polymeric chain constructed both by the bis-tridentate trans-dmapox and bis-monodentate phenyldicarboxylate bridging ligands. In the two complexes, the environment around the copper(II) atoms can be described as distorted square-pyramid and the Cu...Cu separations through mu-trans-dmapox and phenyldicarboxylato bridging ligands are 5.245(5) A and 8.212(3) A for 1, 5.237(8) A and 11.171(1) A for 2, respectively. The binding properties of the two copper(II) polymers with herring sperm DNA (HS-DNA) have been investigated by using absorption and emission spectral and electrochemical techniques and viscometry. The results show that the two copper(II) complexes interact with the HS-DNA in the mode of intercalation with the intrinsic binding constants of 1.22(+/-0.2)x10(4)M(-1) and 1.45(+/-0.3)x10(4)M(-1) for 1 and 2, respectively. PMID:18620754

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

2008-06-08

14

Mixed-valent cobalt spin clusters: a hexanuclear complex and a one-dimensional coordination polymer comprised of alternating hepta- and mononuclear fragments.  

PubMed

Reactions between Co(OAc)2 and 2-amino-2-methyl-1,3-propanediol (ampdH2) afford a hexanuclear complex [Co6(H2O)(MeOH)(OAc)6(ampd)4] (1) and a one-dimensional coordination polymer comprised of discrete heptanuclear complexes covalently bound to mononuclear Co centers [Co8(H2O)2(OAc)7(ampd)6]n (2). While 1 is obtained under ambient reaction conditions, the formation of 2 requires solvothermal methods. Both products have been characterized crystallographically and found to be mixed-valent, containing divalent and trivalent Co centers. Down to 30 K, the variable-temperature magnetic susceptibility data of 1 and 2 are dominated by the single-ion properties of high-spin Co(II) centers with distorted-octahedral coordination geometries. Below this temperature, the effect of intramolecular ferromagnetic exchange interactions becomes apparent. The ferromagnetic coupling in 1 has been analyzed in terms of an anisotropic exchange model, and inelastic neutron scattering data are consistent with the proposed model. Although the structure of 2 precludes a quantitative interpretation, the magnetic data suggest ferromagnetic exchange within the heptanuclear unit and negligible interactions along the chain between the hepta- and mononuclear fragments. PMID:17054354

Alley, Kerwyn G; Bircher, Roland; Waldmann, Oliver; Ochsenbein, Stefan T; Gdel, Hans U; Moubaraki, Boujemaa; Murray, Keith S; Fernandez-Alonso, Felix; Abrahams, Brendan F; Boskovic, Colette

2006-10-30

15

One-Dimensional Cobalt(II) and Zinc(II) Succinato Coordination Polymers with Nicotinamide: Synthesis, Structural, Spectroscopic, Fluorescent and Thermal Properties  

Microsoft Academic Search

Cobalt(II) and zinc(II) succinato (suc) coordination polymers with nicotinamide (nia), {[Co(?-suc)(H2O)2(nia)2]2H2O}\\u000a n\\u000a (1) and {[Zn(?-suc)(H2O)2(nia)2]2H2O}\\u000a n\\u000a (2) have been synthesized and characterized by elemental analyses, magnetic moments, IR and TG-DTA. Single-crystal X-ray analyses\\u000a of 1 and 2 reveal that these complexes are isostructural and crystallize in triclinic space group $$ P\\\\bar{1}.$$ Complexes 1 and 2 are 1-D coordination polymers, in

Selcuk Demir; Veysel T. Yilmaz; Fatih Yilmaz; Orhan Buyukgungor

2009-01-01

16

catena-Poly[[di-?2-aqua-hexaaquabis(?3-4-oxidopyridine-2,6-dicarboxylato)trimanganese(II)] trihydrate]: a new one-dimensional coordination polymer based on a trinuclear Mn(II) complex of chelidamic acid.  

PubMed

4-Hydroxypyridine-2,6-dicarboxylic acid (chelidamic acid, hypydc[H]H2) reacts with MnCl22H2O in the presence of piperazine in water to afford the title complex, {[Mn3(C7H2NO5)2(H2O)8]3H2O}n or {[Mn3(hypydc)2(H2O)8]3H2O}n. This compound is a one-dimensional coordination polymer, with the twofold symmetric repeat unit containing three metal centres. Two different coordination geometries are observed for the two independent Mn(II) metal centres, viz. a distorted pentagonal bipyramid and a distorted octahedron. The 4-oxidopyridine-2,6-dicarboxylate anions and two of the water molecules act as bridging ligands. The zigzag-like geometry of the coordination polymer is stabilized by hydrogen bonds. O-H...O and C-H...O hydrogen bonds and water clusters consolidate the three-dimensional network structure. PMID:24096503

Mirzaei, Masoud; Eshtiagh-Hosseini, Hossein; Karrabi, Zahra; Notash, Behrouz

2013-09-28

17

One-dimensional copper polymers with pentadentate diazine ligands  

Microsoft Academic Search

One-dimensional copper(II) polymers [(Cu4L2)(NO3)4]n (1) and [(Cu4L2)Cl4]n (2) (H2L=salicylaldehyde-2-pyridinecarboxyl-hydrazone) were achieved via self-assembly. The Cu?Cu separations were ca. 2.90 and 4.75 for the phenoxide oxygen bridged pair and the NN bridged pair with antiferromagnetic spin exchanges between Cu(II) ions.

Yan Bai; Dongbin Dang; Xin Cao; Chunying Duan; Qingjin Meng

2006-01-01

18

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)24H2O, 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

19

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

2013-07-30

20

Synthesis, crystal structure, and catalytic properties of a one-dimensional nickel(II) polymer  

Microsoft Academic Search

The title complex [Ni2(C10H9N3)2(C14H8O5)2]\\u000a n\\u000a , which has an inversion center, midway between two Ni(II) atoms forms a one-dimensional polymer bridged by 4,4?-oxydibenzoate\\u000a ligands with a NiNi separation of 14.4705(11) . The Ni(II) atom is six-coordinated by two N atoms of a bis(2-pyridyl)amine\\u000a ligand and four O atoms from two 4,4?-oxydibenzoate ligands, to form a distorted octahedron coordination geometry and

H. Zhong; H. L. Xie; S. H. Duan; M. Li

2009-01-01

21

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

22

One-dimensional reaction coordinates for diffusive activated rate processes in many dimensions.  

PubMed

For multidimensional activated rate processes controlled by diffusive crossing of a saddle point region, we show that a one-dimensional reaction coordinate can be constructed even when the diffusion anisotropy is arbitrary. The rate constant, found using the potential of mean force along this coordinate, is identical to that predicted by the multidimensional Kramers-Langer theory. This reaction coordinate minimizes the one-dimensional rate constant obtained using a trial reaction coordinate and is orthogonal to the stochastic separatrix, the transition state that separates reactants from products. PMID:15638670

Berezhkovskii, Alexander; Szabo, Attila

2005-01-01

23

One-dimensional nanowire assembly based on oriented polymer nanofibers  

Microsoft Academic Search

We develop a simple method for the parallel assembly of nanowires (NWs) based on oriented polymer nanofiber films. The nanowires dispersed in solution are aligned at the central space of parallel nanochannels formed by the well-oriented nanofibers as a result of the capillarity. Then, a general contact printing is used to realize the transfer of the nanowires from the donor

Shancheng Yan; Zhongdang Xiao; Dong Hu; Jiansheng Wu

2011-01-01

24

Brownian-Dynamics Computer Simulations of a One-Dimensional Polymer Model. I. Simple Potentials.  

National Technical Information Service (NTIS)

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. (ERA citation 08:01030...

R. Cook L. L. Livornese

1982-01-01

25

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

NASA Astrophysics Data System (ADS)

A tetrahedrally coordinated cobalt(II) phosphonate, Co(O3PCH2CH2NH2), 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

26

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

SciTech Connect

A tetrahedrally coordinated cobalt(II) phosphonate, Co(O{sub 3}PCH{sub 2}CH{sub 2}NH{sub 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 deg. C. Magnetic susceptibility data are consistent with weak antiferromagnetic ordering at low temperatures.

Gemmill, William R. [Department of Chemistry, James Madison University, Harrisonburg, VA 22807 (United States); Smith, Mark D. [Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208 (United States); Reisner, Barbara A. [Department of Chemistry, James Madison University, Harrisonburg, VA 22807 (United States)]. E-mail: reisneba@jmu.edu

2005-09-15

27

Reaction coordinates, one-dimensional Smoluchowski equations, and a test for dynamical self-consistency  

NASA Astrophysics Data System (ADS)

We propose a method for identifying accurate reaction coordinates among a set of trial coordinates. The method applies to special cases where motion along the reaction coordinate follows a one-dimensional Smoluchowski equation. In these cases the reaction coordinate can predict its own short-time dynamical evolution, i.e., the dynamics projected from multiple dimensions onto the reaction coordinate depend only on the reaction coordinate itself. To test whether this property holds, we project an ensemble of short trajectory swarms onto trial coordinates and compare projections of individual swarms to projections of the ensemble of swarms. The comparison, quantified by the Kullback-Leibler divergence, is numerically performed for each isosurface of each trial coordinate. The ensemble of short dynamical trajectories is generated only once by sampling along an initial order parameter. The initial order parameter should separate the reactants and products with a free energy barrier, and distributions on isosurfaces of the initial parameter should be unimodal. The method is illustrated for three model free energy landscapes with anisotropic diffusion. Where exact coordinates can be obtained from Kramers-Langer-Berezhkovskii-Szabo theory, results from the new method agree with the exact results. We also examine characteristics of systems where the proposed method fails. We show how dynamical self-consistency is related (through the Chapman-Kolmogorov equation) to the earlier isocommittor criterion, which is based on longer paths.

Peters, Baron; Bolhuis, Peter G.; Mullen, Ryan G.; Shea, Joan-Emma

2013-02-01

28

Universal reduction of effective coordination number in the quasi-one-dimensional Ising model  

NASA Astrophysics Data System (ADS)

Critical temperature of quasi-one-dimensional general-spin Ising ferromagnets is investigated by means of the cluster Monte Carlo method performed on infinite-length strips, L? or LL? . We find that in the weak interchain coupling regime the critical temperature as a function of the interchain coupling is well-described by a chain mean-field formula with a reduced effective coordination number, as the quantum Heisenberg antiferromagnets recently reported by Yasuda [Phys. Rev. Lett. 94, 217201 (2005)]. It is also confirmed that the effective coordination number is independent of the spin size. We show that in the weak interchain coupling limit the effective coordination number is, irrespective of the spin size, rigorously given by the quantum critical point of a spin- 1/2 transverse-field Ising model.

Todo, Synge

2006-09-01

29

Flexible and transferable one-dimensional photonic crystals based on polymer infiltrated nanoparticle multilayers  

NASA Astrophysics Data System (ADS)

Herein we present a series of self standing, flexible and transferable one-dimensional photonic crystal obtained through infiltration of a polymer solution in a porous stack prepared by alternating deposition of layers of TiO2 and SiO2 nanoparticles. Since the mesostructure is uniformly filled by the polymer, it is possible to lift off the hybrid multilayers using an adequate thermal treatment to obtain a multifunctional material that combines the optical properties of the periodic nanoporous multilayer and the structural and physic-chemical characteristics of the polymer used. The use of these hybrid 1DPCs as flexible interference filters, or as 1DPC to any kind of substrate is demonstrated.

Calvo, Mauricio E.; Mguez, Hernn

2010-04-01

30

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

31

Infrared phonon anomaly of one-dimensional metallic peanut-shaped C60 polymer  

NASA Astrophysics Data System (ADS)

The infrared (IR) phonon properties of one-dimensional (1D) metallic peanut-shaped C60 polymers, which exhibit an energy gap below 60 K [Y. Toda et al., Appl. Phys. Lett. 92, 094102 (2008)] that is similar to the Peierls transition of quasi-1D metallic materials, have been examined in the temperature range of 30-300 K by high-resolution in-situ IR spectroscopy. We observed an IR phonon anomaly in which two new IR modes appear at 50 K and become increasingly anomalous with decreasing temperature in a similar manner as phase phonons associated with charge density waves in quasi-1D condensates.

Onoe, J.; Takashima, A.; Toda, Y.

2010-12-01

32

Electron-electron interaction effects in quasi-one-dimensional conducting polymers and related systems  

SciTech Connect

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 long-range (V/sub j/, jgreater than or equal to 2) are examined, the former using quantum Monte Carlo and the latter with exact diagonalization of finite size systems and analytic arguments. We also discuss optical absorption properties in the presence of electronic correlation, focusing on the weak and strong coupling limits.

Campbell, D.K.; Baeriswyl, D.; Mazumdar, S.

1986-01-01

33

An Angular Leakage Correction for Modeling a Hemisphere, Using One-Dimensional Spherical Coordinates  

SciTech Connect

A radially dependent, angular leakage correction was applied to a one-dimensional, multigroup neutron diffusion theory computer code to accurately model hemispherical geometry. This method allows the analyst to model hemispherical geometry, important in nuclear criticality safety analyses, with one-dimensional computer codes, which execute very quickly. Rapid turnaround times for scoping studies thus may be realized. This method uses an approach analogous to an axial leakage correction in a one-dimensional cylinder calculation. The two-dimensional Laplace operator was preserved in spherical geometry using a leakage correction proportional to 1/r{sup 2}, which was folded into the one-dimensional spherical calculation on a mesh-by-mesh basis. Hemispherical geometry is of interest to criticality safety because of its similarity to piles of spilled fissile material and accumulations of fissile material in process containers. A hemisphere also provides a more realistic calculational model for spilled fissile material than does a sphere.

Schwinkendorf, K.N.; Eberle, C.S. [Fluor Federal Services (United States)

2003-01-15

34

Semitransparent polymer solar cells with one-dimensional (WO3/LiF)N photonic crystals  

NASA Astrophysics Data System (ADS)

One-dimensional (WO3/LiF)N photonic crystals (1DPCs) are deposited on the Ag cathode of the semitransparent polymer solar cells to improve the efficiency of the device. The 1DPCs with 8 pair of WO3/LiF act as distributed reflectors within the photonic bandgap. Then, power conversion efficiency of 2.58% is achieved and there is an improvement of 26.3% in the efficiency when compared with that of the conventional device without the 1DPCs. The average transmittance of the device with 8 pair of WO3/LiF is almost zero in 400-600 nm wavelength range. It means that the light is absorbed sufficiently in the active layer. The enhanced light absorption results in efficiency improvement remarkably.

Yu, Wenjuan; Shen, Liang; Long, Yongbing; Guo, Wenbin; Meng, Fanxu; Ruan, Shengping; Jia, Xu; Ma, Hongshi; Chen, Weiyou

2012-10-01

35

Multiple time scale dynamics of distance fluctuations in a semiflexible polymer: a one-dimensional generalized Langevin equation treatment.  

PubMed

Time-dependent fluctuations in the distance x(t) between two segments along a polymer are one measure of its overall conformational dynamics. The dynamics of x(t), modeled as the coordinate of a particle moving in a one-dimensional potential well in thermal contact with a reservoir, is treated with a generalized Langevin equation whose memory kernel K(t) can be calculated from the time-correlation function of distance fluctuations C(t) identical with x(0)x(t). We compute C(t) for a semiflexible continuum model of the polymer and use it to determine K(t) via the GLE. The calculations demonstrate that C(t) is well approximated by a Mittag-Leffler function and K(t) by a power-law decay on time scales of several decades. Both functions depend on a number of parameters characterizing the polymer, including chain length, degree of stiffness, and the number of intervening residues between the two segments. The calculations are compared with the recent observation of a nonexponential C(t) and a power law K(t) in the conformational dynamics within single molecule proteins [Min et al., Phys. Rev. Lett. 94, 198302 (2005)]. PMID:16351313

Debnath, Pallavi; Min, Wei; Xie, X Sunney; Cherayil, Binny J

2005-11-22

36

Coordinate Bethe ansatz for the one-dimensional SU(n) Hubbard model with open boundary conditions  

Microsoft Academic Search

The one-dimensional (1D) SU(n) Hubbard model with open boundary condition is solved by using the coordinate Bethe ansatz method. The energy and integrable boundary conditions are obtained. At the same time, the corresponding Bethe ansatz equations are achieved by diagonalizing the inhomogeneous transfer matrix of the open SU(2n-2) XXX vertex model. When n=2, our result comes back to that of

Guang-Liang Li; Rui-Hong Yue; Kang-Jie Shi

2001-01-01

37

Determining the response of infinite, one-dimensional, non-uniform periodic structures by substructuring using waveshape coordinates  

NASA Astrophysics Data System (ADS)

A method is presented for determining the wavenumbers, waveshapes and point receptances for an infinite, one-dimensional, non-uniform periodic structure with distributed periodic attachments or supports. The approach is based on a general theory of harmonic wave propagation in one-dimensional periodic systems. Ill-conditioning was previously reported as an impediment to applying the theory to problems of practical importance. In this paper ill-conditioning problems are overcome and a method of substructuring using waveshape coordinates is presented that dramatically improves computational efficiency. The accuracy and generality of the new method are tested by comparing computed and measured receptances for a typical TGV railway track with UIC60 rail, rail pad, ballast and concrete sleepers. The computed results are found to correlate well with measured data.

Brown, G. P.; Byrne, K. P.

2005-10-01

38

The discontinuous PetrovGalerkin method for one-dimensional compressible Euler equations in the Lagrangian coordinate  

NASA Astrophysics Data System (ADS)

In this paper, a PetrovGalerkin scheme named the RungeKutta control volume (RKCV) discontinuous finite element method is constructed to solve the one-dimensional compressible Euler equations in the Lagrangian coordinate. Its advantages include preservation of the local conservation and a high resolution. Compared with the RungeKutta discontinuous Galerkin (RKDG) method, the RKCV method is easier to implement. Moreover, the advantages of the RKCV and the Lagrangian methods are combined in the new method. Several numerical examples are given to illustrate the accuracy and the reliability of the algorithm.

Zhao, Guo-Zhong; Yu, Xi-Jun; Guo, Peng-Yun

2013-05-01

39

Particle-in-a-box model of one-dimensional excitons in conjugated polymers  

Microsoft Academic Search

A simple two-particle model of excitons in conjugated polymers is proposed as an alternative to usual highly computationally demanding quantum chemical methods. In the two-particle model, the exciton is described as an electron-hole pair interacting via Coulomb forces and confined to the polymer backbone by rigid walls. Furthermore, by integrating out the transverse part, the two-particle equation is reduced to

Thomas G. Pedersen; Per M. Johansen; Henrik C. Pedersen

2000-01-01

40

Anomalous enhancement in the infrared phonon intensity of a one-dimensional uneven peanut-shaped C60 polymer  

NASA Astrophysics Data System (ADS)

A one-dimensional (1D) uneven peanut-shaped C60 polymer formed from electron-beam (EB)-induced polymerization of C60 molecules showed an anomalous increase in two characteristic infrared (IR) peak intensities, which are respectively due to the radial and tangential motion of the 1D polymer, when compared to the IR peaks of pristine C60 films. This anomaly was analyzed on the basis of the vibrational van Hove singularity (VHS), using an extended thin-shell elastic model fully considering the effects of periodic radius modulation inherent to the 1D uneven peanut-shaped C60 polymer. We succeeded in explaining the enhancement in the tangential peak intensity by VHS, whereas the origin to cause that in the radial peak intensity is still unclear.

Onoe, J.; Takashima, A.; Ono, S.; Shima, H.; Nishii, T.

2012-05-01

41

Ultrafast all-optical switching in one-dimensional semiconductor-polymer hybrid nonlinear photonic crystals with relaxing Kerr nonlinearity  

NASA Astrophysics Data System (ADS)

The achievement of ultrafast all-optical switching on chip is a fundamental issue of all-optical integration. A feasible and promising method for this is to combine semiconductor photonic crystals with highly nonlinear polymer materials to form the hybrid nonlinear photonic crystal. In this paper we numerically investigate the femtosecond dynamic response of all-optical switching based on the effect of band gap edge shift in one-dimensional (1D) semiconductor-polymer hybrid nonlinear photonic crystal (NPC) structures. Taking into account the Kerr relaxation time of the polymer and semiconductor materials simultaneously, the introduction of highly nonlinear polymer materials with femtosecond relaxation time can realize all-optical switching in the femtosecond range in spite of the low response speed of the semiconductor materials. The physical origin is the large and ultrafast response Kerr nonlinearity of the polymer materials and this is proved by examining the dependence of switching time on the relaxation speed of the polymer materials. The results can be extended to 2D and 3D NPC structures.

Meng, Zi-Ming; Qin, Fei; Li, Zhi-Yuan

2012-06-01

42

One-dimensional localization effects in three-dimensional structures of highly-conducting polymers  

Microsoft Academic Search

Starting with a model of weakly overlapping metallic chains we developed a transport theory for degenerate electrons in an irregular structure of fibril-form polymers. The anisotropy of intrafibril kinetic characteristics is enhanced by highly anisotropic scattering by dopants. Therefore, in spite of the weak backward impurity scattering, the 1d localization effects can be profound on an intrinsic level. The kinetic

V. N. Prigodin

1997-01-01

43

First-principles calculations of the vibrational spectra of one-dimensional C60 polymers  

NASA Astrophysics Data System (ADS)

The vibrational properties of several C60 dimers belonging to the Stone-Wales rearrangement sequence [described by E. Osawa and K. Honda, Full. Sci. Technol. 4, 939 (1996)], along with a trimer and a tetramer isomer are investigated by tight-binding and density functional calculations. The IR absorption bands found by Onoe, Nakayama, Aono and Hara [Appl. Phys. Lett. 82, 595 (2003)] in the spectra of electron-beam irradiated C60 films are explained and attributed mainly to surface vibrations located in the waist region of the considered polymers. The features of the Raman spectra are also discussed and related to experimental spectra of photopolymerized C60 .

Beu, Titus A.; Onoe, Jun

2006-11-01

44

An RKDG finite element method for the one-dimensional inviscid compressible gas dynamics equations in a Lagrangian coordinate  

NASA Astrophysics Data System (ADS)

In this paper, RungeKutta Discontinuous Galerkin (RKDG) finite element method is presented to solve the one-dimensional inviscid compressible gas dynamic equations in a Lagrangian coordinate. The equations are discretized by the DG method in space and the temporal discretization is accomplished by the total variation diminishing RungeKutta method. A limiter based on the characteristic field decomposition is applied to maintain stability and non-oscillatory property of the RKDG method. For multi-medium fluid simulation, the two cells adjacent to the interface are treated differently from other cells. At first, a linear Riemann solver is applied to calculate the numerical flux at the interface. Numerical examples show that there is some oscillation in the vicinity of the interface. Then a nonlinear Riemann solver based on the characteristic formulation of the equation and the discontinuity relations is adopted to calculate the numerical flux at the interface, which suppresses the oscillation successfully. Several single-medium and multi-medium fluid examples are given to demonstrate the reliability and efficiency of the algorithm.

Zhao, Guo-Zhong; Yu, Xi-Jun; Zhang, Rong-Pei

2013-02-01

45

Wells Dawson anion, a useful building block to construct one-dimensional chain as a chelate ligand coordinating with transition metal cations  

NASA Astrophysics Data System (ADS)

Two composite compounds, [{Cu(PPD)2}(As2W18O60)]2H2PPD14H2O 1 (PPD = p-phenylenediamine) and [Cu4(Hen)2As2W18O68]4H2en18H2O 2 (en = ethylenediamine) have been prepared under mild hydrothermal conditions with difference in pH values of the initial reaction solutions and structurally characterized by single-crystal X-ray diffraction. Compound 1 exhibits a one-dimensional chain constructed from Wells Dawson anions and Cu(II) coordination complex. It is the first example of a one-dimensional chain based on Wells Dawson anions that act as chelate ligands to coordinate with transition metal. Compound 2 is constructed from trivacant Keggin polyanions linked through tetrameric copper unit, which coordinates with organonitrogen ligands.

Fan, Linlin; Wang, Enbo; Li, Yangguang; An, Haiyan; Xiao, Dongrong; Wang, Xinlong

2007-09-01

46

The competition between CDW and SDW in quasi-one-dimensional organic magnetic polymer with interchain coupling interaction  

NASA Astrophysics Data System (ADS)

Based on a theoretical model proposed for interchain-coupled quasi-one-dimensional organic magnetic polymer, the effects of the interchain couplings and electron electron interactions on the charge density wave (CDW) and spin density wave (SDW) that exist in the system are studied. It is found that the amplitude of the SDW along the main chain will decrease with increasing of the oscillatory term of the interchain couplings in the system, which is unfavorable to the ferromagnetic ground state of the system. Moreover, with different interchain couplings, there will all exist a critical value of the inter-site electron electron Coulomb repulsion, and at this value, the system will experience a transformation from strong SDW state to strong CDW one, which will weaken the mediating function of the antiferromagnetic SDW along the main chain. As a result, the ferromagnetic correlation intensity between the spins of the side radicals will be affected and consequently the stability of the ferromagnetic state in the system will be weakened.

Zhao, L.; Gong, K.; Wang, J.

2007-09-01

47

Static fluctuations of a thick one-dimensional interface in the 1+1 directed polymer formulation: numerical study.  

PubMed

We study numerically the geometrical and free-energy fluctuations of a static one-dimensional (1D) interface with a short-range elasticity, submitted to a quenched random-bond Gaussian disorder of finite correlation length ?>0 and at finite temperature T. Using the exact mapping from the static 1D interface to the 1+1 directed polymer (DP) growing in a continuous space, we focus our analysis on the disorder free energy of the DP end point, a quantity which is strictly zero in the absence of disorder and whose sample-to-sample fluctuations at a fixed growing time t inherit the statistical translation invariance of the microscopic disorder explored by the DP. Constructing a new numerical scheme for the integration of the Kardar-Parisi-Zhang evolution equation obeyed by the free energy, we address numerically the time and temperature dependence of the disorder free-energy fluctuations at fixed finite ?. We examine, on one hand, the amplitude D[over ?](t) and effective correlation length ?[over ?](t) of the free-energy fluctuations and, on the other hand, the imprint of the specific microscopic disorder correlator on the large-time shape of the free-energy two-point correlator. We observe numerically the crossover to a low-temperature regime below a finite characteristic temperature T(c)(?), as previously predicted by Gaussian variational method computations and scaling arguments and extensively investigated analytically in [Phys. Rev. E 87, 042406 (2013)]. Finally, we address numerically the time and temperature dependence of the roughness B(t), which quantifies the DP end point transverse fluctuations, and we show how the amplitude D[over ?](?)(T,?) controls the different regimes experienced by B(t)-in agreement with the analytical predictions of a DP toy model approach. PMID:23848695

Agoritsas, Elisabeth; Lecomte, Vivien; Giamarchi, Thierry

2013-06-17

48

Static fluctuations of a thick one-dimensional interface in the 1+1 directed polymer formulation: Numerical study  

NASA Astrophysics Data System (ADS)

We study numerically the geometrical and free-energy fluctuations of a static one-dimensional (1D) interface with a short-range elasticity, submitted to a quenched random-bond Gaussian disorder of finite correlation length ?>0 and at finite temperature T. Using the exact mapping from the static 1D interface to the 1+1 directed polymer (DP) growing in a continuous space, we focus our analysis on the disorder free energy of the DP end point, a quantity which is strictly zero in the absence of disorder and whose sample-to-sample fluctuations at a fixed growing time t inherit the statistical translation invariance of the microscopic disorder explored by the DP. Constructing a new numerical scheme for the integration of the Kardar-Parisi-Zhang evolution equation obeyed by the free energy, we address numerically the time and temperature dependence of the disorder free-energy fluctuations at fixed finite ?. We examine, on one hand, the amplitude Dt and effective correlation length ?t of the free-energy fluctuations and, on the other hand, the imprint of the specific microscopic disorder correlator on the large-time shape of the free-energy two-point correlator. We observe numerically the crossover to a low-temperature regime below a finite characteristic temperature Tc(?), as previously predicted by Gaussian variational method computations and scaling arguments and extensively investigated analytically in [Phys. Rev. E1539-375510.1103/PhysRevE.87.042406 87, 042406 (2013)]. Finally, we address numerically the time and temperature dependence of the roughness B(t), which quantifies the DP end point transverse fluctuations, and we show how the amplitude D?(T,?) controls the different regimes experienced by B(t)in agreement with the analytical predictions of a DP toy model approach.

Agoritsas, Elisabeth; Lecomte, Vivien; Giamarchi, Thierry

2013-06-01

49

Laser Action Based on Electrically Controllable Defect Mode in One-Dimensional Photonic Crystal Containing Conducting Polymer and Liquid Crystal Defect Layers  

Microsoft Academic Search

Electrical tuning of the wavelength of a defect mode lasing in a one-dimensional photonic crystal has been demonstrated using a conducting polymer as an active emission layer and a nematic liquid crystal as an electrically tunable defect layer in the periodic structure. Lasing wavelength is widely tuned upon applying the electric field, which follows a defect mode shift due to

Ryotaro Ozaki; Yuko Matsuhisa; Masanori Ozaki; Katsumi Yoshino

2005-01-01

50

Coordination polymers containing ferrocene backbone. Synthesis, structure and electrochemistry.  

PubMed

The reaction of 1,1'-ferrocenedicarboxylic acid (LH(2)) with bis(triphenyltin) oxide afforded a molecular heterobimetallic compound [(Ph(3)Sn)(2)L]. In the latter the two carboxylate units of [L](2-) are involved in an anisobidentate chelating coordination mode to two triphenyl tin units. The reaction of LH(2) with trimethyltin hydroxide or bis(tri-n-butyltin) oxide afforded 2D-coordination polymers [(Me(3)Sn)(2)L](n) and [(n-Bu(3)Sn)(2)L](n) which are formed as a result of anisobidentate bridging coordination action of the two carboxylate units of [L](2-). Interestingly the 2D-coordination polymers contain 24-membered macrocycles each of which is comprised of four trialkyl tin units. The coordination unsaturation of [(Ph(3)Sn)(2)L] can be utilized to form coordination polymers. Accordingly the reaction of LH(2) with bis(triphenyltin) oxide in the presence of ditopic nitrogen ligands such as 4,4'-bipyridine, 4,4'-trimethylenebipyridine or 4,4'-vinylenebipyridine afforded one-dimensional coordination polymers which contain in their backbone three distinct structural components viz., two triorganotin units, a ferrocenyl unit and a bridging nitrogen ligand unit. The coordination polymers, however, do not retain their structural integrity in solution and fall apart to their monomeric units. Electrochemical studies on these hybrid orgaonotin/ferrocene systems reveal that most of them exhibit a single quasi-reversible oxidation peak. PMID:20179864

Chandrasekhar, Vadapalli; Thirumoorthi, Ramalingam

2010-01-28

51

Failure of one-dimensional Smoluchowski diffusion models to describe the duration of conformational rearrangements in floppy, diffusive molecular systems: A case study of polymer cyclization  

NASA Astrophysics Data System (ADS)

Motivated by recent experimental efforts to measure the duration of individual folding/unfolding transitions in proteins and RNA, here we use simulations to study the duration of a simple transition mimicking an elementary step in biopolymer folding: the closure of a loop in a long polymer chain. While the rate of such a transition is well approximated by a one-dimensional Smoluchowski model that views the end-to-end distance dynamics of a polymer chain as diffusion governed by the one-dimensional potential of mean force, the same model fails rather dramatically to describe the duration of such transitions. Instead, the latter timescale is well described by a model where the chain ends diffuse freely, uninfluenced by the average entropic force imposed by the polymer chain. The effective diffusion coefficient then depends on the length scale of the loop closure transition. Our findings suggest that simple one-dimensional models, when applied to estimate the duration of reactive events in complex molecular systems, should be used with caution.

Cheng, Ryan R.; Makarov, Dmitrii E.

2011-02-01

52

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

53

Porphyrin coordination polymer nanospheres and nanorods  

SciTech Connect

A porphyrin coordination polymer nanostructure comprising a network of pyridyl porphyrin molecules and coordinating metal ions coordinatively bound through the pyridyl groups. In some embodiments, the porphyrins are metalloporphyrins. A variety of nanostructures are formed by the network polymer, including nanospheres, polygonal nanostructures, nanorods, and nanofibers, depending on a variety of factors including coordination metal ion, porphyrin type, metal of the metalloporphyrin, and degree of agitation during nanostructure formation. Reduction of coordinating metal ions may be used to form metal nanoparticles on the coordination polymer nanostructure.

Wang, Zhongchun; Shelnutt, John A.; Medforth, Craig J.

2012-12-04

54

In situ infrared spectroscopic and density-functional studies of the cross-linked structure of one-dimensional C60 polymer  

NASA Astrophysics Data System (ADS)

We have examined the infrared (IR) spectra of electron-beam (EB) irradiated C60 films, using in situ IR spectroscopy in the temperature range of 60-300 K. The irradiation-time evolution of the IR spectra shows that two highly intense new peaks finally appear around 565 and 1340 cm-1 when the EB-induced C60 polymerization was saturated. To determine the cross-linked structure of the polymer explicitly, we have compared the IR spectra with theoretical spectra obtained from the cross-linked structure of all C120 stable isomers derived from the general Stone-Wales (GSW) rearrangement, using first-principles density-functional calculations. Since each C120 isomer has the same cross-linked structure as that of its corresponding one-dimensional (1D) C60 polymer, the IR modes obtained from the cross-linked structure of C120 are close to those obtained from the corresponding 1D polymer. Comparison between the experimental and theoretical IR spectra suggests that the 1D peanut-shaped C60 polymer has a cross-linked structure roughly similar to that of the P08 peanut-shaped C120 isomer.

Takashima, A.; Onoe, J.; Nishii, T.

2010-08-01

55

In situ infrared spectroscopic and density-functional studies of the cross-linked structure of one-dimensional C{sub 60} polymer  

SciTech Connect

We have examined the infrared (IR) spectra of electron-beam (EB) irradiated C{sub 60} films, using in situ IR spectroscopy in the temperature range of 60-300 K. The irradiation-time evolution of the IR spectra shows that two highly intense new peaks finally appear around 565 and 1340 cm{sup -1} when the EB-induced C{sub 60} polymerization was saturated. To determine the cross-linked structure of the polymer explicitly, we have compared the IR spectra with theoretical spectra obtained from the cross-linked structure of all C{sub 120} stable isomers derived from the general Stone-Wales (GSW) rearrangement, using first-principles density-functional calculations. Since each C{sub 120} isomer has the same cross-linked structure as that of its corresponding one-dimensional (1D) C{sub 60} polymer, the IR modes obtained from the cross-linked structure of C{sub 120} are close to those obtained from the corresponding 1D polymer. Comparison between the experimental and theoretical IR spectra suggests that the 1D peanut-shaped C{sub 60} polymer has a cross-linked structure roughly similar to that of the P08 peanut-shaped C{sub 120} isomer.

Takashima, A.; Onoe, J. [Department of Nuclear Engineering and Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, O-okayama, Meguro, Tokyo 152-8550 (Japan); Nishii, T. [Technology Development Center, Electric Power Development Co., Ltd. (J-Power), Chigasaki, Kanagawa 253-0041 (Japan)

2010-08-15

56

Structure and electronic properties of the nanopeapods-One dimensional C{sub 60}O polymer encapsulated in single-walled carbon nanotubes  

SciTech Connect

The structure-property relationship of the nanopeapods-one dimensional (1D) C{sub 60}O polymer encapsulated in single-walled carbon nanotubes (SWCNTs)-is studied by means of the self-consistent field crystal orbital method. The calculations show that the nearest distance between the two constituents is within Van der Waals interaction scope in the most stable two peapods. The SWCNT sizes affect not only the stability but also the electronic structures of the peapods. The peapods with larger tube diameters keep the semiconductive and metallic properties of the corresponding pristine SWCNTs. These combination systems are stiffer than the corresponding SWCNTs due to larger Young's moduli. The magnitude order of the calculated mobility of charge carriers is in the range of 10{sup 2}-10{sup 5} cm{sup 2} V{sup -1} s{sup -1} for the peapods, indicating that the combined systems may be good high-mobility electronic materials. - Graphical abstract: Formation of the novel peapod-1D C{sub 60}O polymer encapsulated inside single-walled carbon nanotube. Highlights: Black-Right-Pointing-Pointer Several novel peapods encapsulating one dimensional C{sub 60}O polymers are constructed. Black-Right-Pointing-Pointer Interwall distance of the two most stable peapods is in the Van der Waals scope. Black-Right-Pointing-Pointer All peapods studied are stiffer than the corresponding SWCNTs. Black-Right-Pointing-Pointer These peapods have high mobilies-in the order of 10{sup 2}-10{sup 5} cm{sup 2} V{sup -1} s{sup -1}.

Qiao Weiye [College of Chemistry, Beijing Normal University, Beijing 100875 (China); Li Xinqian [Institute for Materials Chemistry and Engineering and International Research Center for Molecular Systems, Kyushu University, Fukuoka 819-0395 (Japan); Bai Hongcun; Zhu Ying [College of Chemistry, Beijing Normal University, Beijing 100875 (China); Huang Yuanhe, E-mail: yuanhe@bnu.edu.cn [College of Chemistry, Beijing Normal University, Beijing 100875 (China)

2012-02-15

57

Coordination Polymers as Possible Organic Semiconductors.  

National Technical Information Service (NTIS)

The purpose of this research was to prepare organometallic coordination polymers that might prove of value as semiconductors. Arguments proposed earlier suggested that organic semiconductors could be useful only if they are (a) completely conjugated; (b) ...

M. J. S. Dewar

1966-01-01

58

Topology, chirality and interpenetration in coordination polymers.  

PubMed

This Viewpoint turns back the clock to 1998 when a contribution by Carlucci, Ciani, Macchi and Proserpio (Chem. Commun., 1998, 1837-1838) addressed the existence of multiple properties in coordination polymer networks and the use of topology for classifying network connectivity, thereby serving as a presage of the exponential growth in the field of coordination polymers that continues unabated to this day. PMID:24030700

Zhang, Shi-Yuan; Zhang, Zhenjie; Zaworotko, Michael J

2013-09-26

59

Azide-bridged one-dimensional Mn(III) polymers: effects of side group of Schiff base ligands on structure and magnetism.  

PubMed

By changing ancillary tetradentate Schiff base ligands (L), two new one-dimensional azide-bridged manganese(III) coordination complexes [MnIII(L)(mu1,3-N3)]n [L = 5-Fsalen (1), 5-OCH3 (2); salen = N,N'-bis(salicylidene)-1,2-diaminoethane] as well as a mononuclear complex [MnIII(salophen)(N3)] (3) [salophen = N,N'-bis(salicylidene)-o-phenylenediamine] have been successfully obtained. All of them have been structurally and magnetically characterized. In the structures of 1-3 each MnIII ion is in a distorted octahedral geometry with an obvious Jahn-Teller effect, where the tetradentate L ligands all bind in the equatorial mode, whereas in the axial direction, the N3- ion acts as an end-to-end bridge in 1 and 2 while a terminal group in 3 with a methanol molecule at the other end. Magnetic characterization shows that the mu1,3-bridging azide ion proves to mainly transmit antiferromagnetic interaction between MnIII ions, but these three complexes exhibit various magnetic behaviors at low temperatures. Noteworthily, complex 2 behaves as a weak ferromagnet with a relatively large coercive field of 2.3 kOe, much larger than the value reported previously. PMID:18031035

Yuan, Mei; Zhao, Fei; Zhang, Wen; Wang, Zhe-Ming; Gao, Song

2007-11-22

60

One Dimensional Collision Model  

NSDL National Science Digital Library

The One Dimensional Collision model allows the user to collide two objects and investigate whether momentum and/or kinetic energy are conserved in the collision process. To keep things simple, we'll confine ourselves to collisions along a single line. Special cases include the completely inelastic case, in which the objects stick together after the collision, as well as the completely elastic case, in which kinetic energy is conserved. The One Dimensional Collision was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_Collisions1D.jar file will run the program if Java is installed.

Duffy, Andrew

2010-04-28

61

One-Dimensionality and Whiteness  

ERIC Educational Resources Information Center

|This article is a theoretical discussion that links Marcuse's concept of one-dimensional society and the Great Refusal with critical race theory in order to achieve a more robust interrogation of whiteness. The author argues that in the context of the United States, the one-dimensionality that Marcuse condemns in "One-Dimensional Man" is best

Calderon, Dolores

2006-01-01

62

Metal Coordination Polymers as Potential High-Energy Lithographic Resists.  

National Technical Information Service (NTIS)

Over the past few years we have developed a number of linear coordination polymers which have interesting properties. One type of study has centered on polymers which would provide sensitive lithographic resists based on the fact that the photoelectric ef...

P. V. West R. D. Archer V. J. Tramontano V. O. Ochaya W. Cumming

1989-01-01

63

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

2012-01-23

64

Two Picolinamide-Based Zn(II) Coordination Polymers: Syntheses, Structures, and Catalytic Activities  

Microsoft Academic Search

Two picolinamide-based zinc(II) coordination polymers {[Zn(SO4)(3-bpit) (CH3OH)2]2CH3OH}n (1)(3-bpit = N,N-bis(3-pyridylformyl)imidazolidine-2-thione) and [Zn(SCN)2(4-bpit)]n (2) (4-bpit = N,N-bis(4-pyridylformyl)imidazolidine -2-thione) have been synthesized and structurally characterized. In complexes 1 and 2, the picolinamide-based ligands, 3-bpit and 4-bpit, function as bridging bidentate mode, leading to polymeric structures. Complex 1 is a two-dimensional coordination polymer while 2 exhibits a one-dimensional chain structure. The hydrolysis of

Linke Li; Hongchang Yao; Jingjing Zhao; Zhihui Yang; Hongwei Hou

2012-01-01

65

Coordination Polymers Constructed from alkoxo-bridged nodes and exo-bidentate Ligands  

NASA Astrophysics Data System (ADS)

Three new coordination polymers have been obtained by using alkoxo-bridged copper(II) complexes as nodes, and exo-bidentate ligands as spacers (bis(4-pyridyl)ethane, bpeta, bis(4-pyridyl)propane, bpp, and pyrazine, pyr): [Cu2(pa)2(C2H5OH)2(bpeta)](BF4)21; [Cu4(pa)4(bpp)4(ClO4)2](ClO4)22H2O 2; [Cu2(mea)2(pyr)2](CF3SO3)23 (pa stands for the anion of propanolamine, and mea for the one of monoethanolamine). The crystallographic investigation of the three compounds reveals one-dimensional coordination polymers in 1 and 2, and grid-like layers in 3.

Marin, Geanina; Kravtsov, Victor; Simonov, Yurii A.; Tudor, Violeta; Lipkowski, Janusz; Andruh, Marius

2006-08-01

66

Synthesis and magneto-structural correlation of a new maleato bridged copper(II) coordination polymer  

Microsoft Academic Search

A one-dimensional (1-D) copper(II) coordination polymer [Cu(maleate)(2,2?-bipyridyl)]\\u000a n\\u000a ?2H2O has been synthesised. Single crystal X-ray diffraction study reveals that maleate ion bridges two adjacent copper(II) centres\\u000a along the chain in a synanti fashion. A complete cryomagnetic investigation of the title complex correlates well with the distorted square pyramidal geometry\\u000a of the central copper(II) ion and bridging nature of the maleate.

Shyamapada Shit; Joy Chakraborty; Anamika Das; Glenn P. A. Yap; M. S. El. Fallah; Samiran Mitra

2007-01-01

67

Formation process and electron-beam incident energy dependence of one-dimensional uneven peanut-shaped C60 polymer studied using in situ high-resolution infrared spectroscopy and density-functional calculations  

NASA Astrophysics Data System (ADS)

A 3 kV electron-beam irradiation of a C60 film gives rise to formation of one-dimensional (1D) uneven peanut-shaped C60 polymer with a cross-linked structure close to that of the P08 C120 stable isomer obtained from the general Stone-Wales rearrangement. In this study, we examined the evolution of infrared (IR) spectra of C60 films with respect to electron beam (EB) irradiation time, using in situ high-resolution IR spectroscopy and first-principles density-functional calculations, and found semi-quantitatively that the 1D uneven peanut-shaped C60 polymer is formed via intermediate polymers with a cross-linkage close to that of P04 and P06 C120 isomers obtained from GWS rearrangement. In addition, we examined the dependence of EB-induced C60 polymerization on an incident energy of EB in the range 3-7 kV. IR spectra obtained for 5 and 7 kV EB irradiation of C60films showed the same product as for 3 kV EB irradiation. However, when 5 and 7 kV EBs continued to irradiate C60 films for a long time after the polymer formation, the 1D peanut-shaped polymer did not proceed to become 1D polymers with a more coalesced linkage than that of the P08 one but was destroyed to become amorphous carbons.

Takashima, Akito; Nishii, Toshiaki; Onoe, Jun

2012-12-01

68

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

NASA Astrophysics Data System (ADS)

Two Cu(II) coordination polymers were synthesized with a new semi-rigid V-type dicarboxylate ligand with hydroxyl groups.Complexes 1 and 2 display double- and single-zigzag chain structures, respectively.The framework of 1 possesses one-dimensional rhombic channels.Complexes 1 and 2 exhibit moderate thermal stabilities.

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

2013-08-01

69

One-dimensional cobalt and zinc complexes involving in situ reaction of ethylenediamine and acetonitrile to form imidazoline ligand  

Microsoft Academic Search

The solvothermal treatment of cobalt nitrate (or zinc acetate), ethylenediamine and dicarboxylate in acetonitrile produced two one-dimensional coordination polymers [Co(mimz)2(ox)]n (1) and [Zn(mimz)2(ip)]n (2) (mimz = 2-methylimidazoline, ox=oxalate, ip=isophthalate) which ligand involving in situ formation of imidazoline ligand by cycloaddition reaction of ethylenediamine and acetonitrile.

Zheng-Ming Hao; Xian-Ming Zhang

2006-01-01

70

Synthesis and structure of an unprecedented supramolecular bridged-hydroxyl manganese(III)-lithium(I) coordination polymer [Mn IIIL(OH) 2Li I] n through both intermolecular hydrogen bonds and ?? stacking interactions  

Microsoft Academic Search

An unprecedented linear supramolecular manganese(III)-lithium(I) coordination polymer, [MnIIIL(OH)2LiI]n, has been prepared and structurally characterized. The polymer is a one-dimensional infinite Mn(III)OLi(I) chain supramolecular structure formed by intermolecular OHO and OHCl hydrogen bonds and ?? stacking of neighboring benzene rings.

Wen-Kui Dong; Chun-Yu Zhao; Yin-Xia Sun; Xiao-Lu Tang; Xue-Ni He

2009-01-01

71

One-Dimensional Anharmonic Oscillator.  

National Technical Information Service (NTIS)

We have obtained, in a closed form, the energy levels of a one-dimensional anharmonic oscillator (a.o.) ax sup 2 + beta x sup 4 using the 1st order of the so-called modified perturbation theory (MPT) as well as WKB method. The calculations were performed ...

G. N. Afanas'ev A. G. Gal'perin

1986-01-01

72

Crystal structures and luminescent properties of lanthanide nitrate coordination polymers with structurally related amide type bridging podands  

NASA Astrophysics Data System (ADS)

A one-dimensional linear chain coordination polymer [ErLI(NO3)3(CH3CO2Et)]n (LI=1,2-bis{[(2'-furfurylaminoformyl)phenoxyl]methyl}benzene) and a one-dimensional zig-zag coordination polymer {[TbLII(NO3)3(H2O)](H2O)}n (LII=1,2-bis{[2'-(2-pyridylmethylaminoformyl)phenoxyl]methyl}benzene) were assembled by two structurally related bridging podands LI and LII which have uniform skeleton and different terminal groups. In {[TbLII(NO3)3(H2O)](H2O)}n, the neutral chains were linked by the hydrogen bonding interactions between the free and coordinated water molecules from two different directions to interpenetrate into a 3D supramolecular structure. At the same time, the luminescent properties of the solid Tb(III) nitrate complexes of these podands were investigated at room temperature. The lowest triplet state energy levels T1 of the podands LI and LII indicate that the triplet state energy levels of the antennae are both above the lowest excited resonance level of 5D4 of Tb3+ ion. Thus the absorbed energy could be transferred from ligands to the central Tb3+ ions. And the influence of the hydrogen bonding on the luminescence efficiencies of the coordination polymers was also discussed.

Wang, Qing; Yan, Xuhuan; Zhang, Hongrui; Liu, Weisheng; Tang, Yu; Tan, Minyu

2011-01-01

73

Anions behaviors for the dimensionalities of coordination polymers based on poly(imidazole) ligands  

NASA Astrophysics Data System (ADS)

To explore the influence for the dimensionalities of coordination polymers, in presence of different anions with different behaviors, three new coordination polymers with different dimensionalities have been prepared by reacting M2+ (M = Zn or Co) with two structurally related rod-like poly(imidazole) ligands, 1,4-bis(benzoimidazol-1-yl)-phenyl (L1) and 1,4-bis(imidazol-1-yl)-phenyl (L2). Such three new coordination polymers with different architectures, [Zn(L1)(NO3)2]n (1), {[Zn(L2)2]2BF42HCCl32H2O}n (2) and [Co(L2)(SO4)]n (3), have been determined by single-crystal X-ray diffraction analysis and characterized by elemental analysis, and IR analysis. Complex 1 is alternative linked by octahedral Zn centers and the ligand L1 to exhibit a one-dimensional (1D) chain structure. However, complexes 2 and 3 both present layered structures contain a similar -L(ligand)-M(metal)-L-M- chain motifs that found in complex 1. In complex 2, each Zn(II) ion is coordinated by four different L2 to form a undulated sheet. Complex 3 also present a undulated sheet structure, however, they were connected by the SO42- group and the L2 ligands, different from only of the L2 ligands in complex 2. The result indicates that the different anions behaviors could be the great influence on the degree of dimensionality of coordination polymers.

Pan, Qinhe; Ma, Hong; Li, Zuo-Xi; Hu, Tong-Liang

2012-03-01

74

Crystal structures and luminescent properties of lanthanide nitrate coordination polymers with structurally related amide type bridging podands  

SciTech Connect

A one-dimensional linear chain coordination polymer [ErL{sup I}(NO{sub 3}){sub 3}(CH{sub 3}CO{sub 2}Et)]{sub n} (L{sup I}=1,2-bis{l_brace}[(2'-furfurylaminoformyl)phenoxyl]methyl{r_brace}benzene) and a one-dimensional zig-zag coordination polymer {l_brace}[TbL{sup II}(NO{sub 3}){sub 3}(H{sub 2}O)].(H{sub 2}O){r_brace}{sub n} (L{sup II}=1,2-bis{l_brace}[2'-(2-pyridylmethylaminoformyl)phenoxyl]methyl{r_brace}benzene) were assembled by two structurally related bridging podands L{sup I} and L{sup II} which have uniform skeleton and different terminal groups. In {l_brace}[TbL{sup II}(NO{sub 3}){sub 3}(H{sub 2}O)].(H{sub 2}O){r_brace}{sub n}, the neutral chains were linked by the hydrogen bonding interactions between the free and coordinated water molecules from two different directions to interpenetrate into a 3D supramolecular structure. At the same time, the luminescent properties of the solid Tb(III) nitrate complexes of these podands were investigated at room temperature. The lowest triplet state energy levels T{sub 1} of the podands L{sup I} and L{sup II} indicate that the triplet state energy levels of the antennae are both above the lowest excited resonance level of {sup 5}D{sub 4} of Tb{sup 3+} ion. Thus the absorbed energy could be transferred from ligands to the central Tb{sup 3+} ions. And the influence of the hydrogen bonding on the luminescence efficiencies of the coordination polymers was also discussed. -- Graphical Abstract: Two one-dimensional lanthanide coordination polymers were assembled by two structurally related bridging podands, and the effects of the structures on luminescent properties of the solid Tb(III) nitrate complexes were investigated. Display Omitted Research highlights: > Two structurally related amide type bridging ligands were designed and synthesized. > Two one dimensional lanthanide nitrate coordination polymers were obtained. > The structure effects on luminescent properties of the terbium complexes were discussed.

Wang, Qing; Yan, Xuhuan; Zhang, Hongrui; Liu, Weisheng [Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Tang, Yu, E-mail: tangyu@lzu.edu.c [Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China); Tan, Minyu [Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000 (China)

2011-01-15

75

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

76

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

77

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

78

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

79

Tunable selectivity of lanthanide ion exchange within a coordination polymer.  

PubMed

The exchange of lanthanide(III) ions (Ln(3+)) between a solution and a coordination polymer (CP) formed by cerium(III) or samarium(III) ion and an organophosphorous ligand has been studied. The CPs exhibit distinctive Ln(3+) affinity that varies with a small change in its framework, depending on the central Ln(3+). PMID:23842409

Tasaki-Handa, Yuiko; Ooi, Kenta; Tanaka, Mikiya; Wakisaka, Akihiro

2013-01-01

80

On the Laws of Polycoordination and New Coordination Polymers.  

National Technical Information Service (NTIS)

It was found possible to obtain coordination polymers by polyrecombination (4.4'-bis(acetoacetyl) phenyl ether + Be); by the reaction of ethers with terminal acetoacetate groups having metallic derivatives (diacetate acetones of N-xylyleneglycol and di-(b...

V. V. Korshak S. V. Vinogradova V. A. Artemova T. M. Babchintser S. A. Pavlova

1964-01-01

81

One Dimensional Magnetic Dichalcogenide Nanostructures  

NASA Astrophysics Data System (ADS)

The transition metal dichalcogenides are a class of layered 2D materials with a rich variety of electron and, with doping, magnetic characteristics. They are structurally akin to graphite and, like their carbon based analogs, can be induced to form various low dimensional nanostructures. One dimensional forms are of particular interest, with the dichalcogenides forming nanometer scale tapes, rods, or hollow tubes. Given the novel properties of the bulk analogs of these materials, these 1D nanostructures could provide novel pathways for studying the effects of dimensional confinement. However, one aspect of the macroscopic systems that has not been repeated for the 1D nanostructures is the ability to dope the nanostructures with magnetic ions. By modifying the synthesis process, we have been able to overcome this obstacle to create highly 1D dichalcogenide structures with spin-glass like or ferromagnetic ground states. We hope to extend this technique to be able to create a variety of such nanostructures to explore how quantum size effects can alter the base magnetic properties of these materials.

Kidd, Timothy; O'Shea, Aaron; Shand, Paul; Strauss, Laura

2011-11-01

82

Neutron Scattering from a Coordination Polymer Spin-1/2 Ladder  

NASA Astrophysics Data System (ADS)

Charge and spin dynamics in Heisenberg spin 1/2 ladders have attracted much attention because of their possible relevance to high-TC superconductivity. Coordination polymer magnets are excellent systems in which to explore quantum magnetism. However, several previous coordination polymers thought to be spin ladders have turned out to contain alternating spin chains or dimers coupled in two or three dimensions. Here we investigate another possible spin ladder system Cu(Quinoxaline)Br2, in which neutral Cu2Br4 dimers appear linked to adjacent dimers by bridging quinoxaline molecules along the monoclinic b axis. Inelastic neutron scattering measurements were carried out on a powder sample. The singular onset of magnetic scattering above a finite gap, ?=1.9 meV, in the spectrum indicates that the material is magnetically one-dimensional. Consideration of the crystal structure suggests that Cu(Quinoxaline)Br2 in that case should be a spin ladder system. We also calculated the one-triplon contribution to the inelastic magnetic scattering by the method of continuous unitary transformation. The excellent agreement with the experimental data supports that conclusion. Final confirmation that Cu(Quinoxaline)Br2 is a spin ladder will require single crystal neutron scattering experiments.

Hong, Tao; Turnbull, M. M.; Schmidt, K. P.; Qiu, Y.; Broholm, C.

2005-03-01

83

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

2012-10-03

84

Syntheses, crystal structures and thermal properties of six coordination polymers based on 2-(p-methylphenyl)-imidazole dicarboxylate.  

PubMed

Through solvothermal reactions of 2-(p-methylphenyl)-1H-imidazole-4,5-dicarboxylic acid (p-MePhH3IDC) with transition-metal ions, six coordination polymers [Pb2(p-MePhHIDC)(p-MePhH2IDC)2(phen)2]n (phen = 1,10-phenanthroline) (), [Pb(p-MePhH2IDC)2]n (), [Cd3(p-MePhHIDC)2(p-MePhH2IDC)2(H2O)2]n (), {[Cd(p-MePhHIDC)(H2O)]4H2O}n (), {[Cd2(p-MePhHIDC)2(4,4'-bipy)]4H2O}n (4,4'-bipy = 4,4'-bipyridine) () and [Mn3(p-MePhHIDC)2(p-MePhH2IDC)2(4,4'-bipy)]n () have been synthesized successfully. X-ray single-crystal analyses show that polymers have rich structural chemistry ranging from one-dimensional (), two-dimensional () to three-dimensional polymers (, , and ). In these polymers, the p-MePhH3IDC ligand shows flexible coordination modes tuned by different synthetical conditions, including the addition of coligands, temperature, pH value and so on. Furthermore, the polymers have been investigated by solid-state ultraviolet spectra and thermogravimetric analyses. PMID:23982821

Zhang, Yu; Yuan, Pengfei; Zhu, Yanyan; Li, Gang

2013-10-01

85

Microporous coordination polymers as selective sorbents for liquid chromatography.  

PubMed

We evaluate the potential of microporous coordination polymers (MCPs) to act as the stationary phase in liquid chromatographic separations. MCPs derived from carboxylates coordinated to copper (HKUST-1) and zinc (MOF-5) were studied. The shape and size selective separation of organic compounds including benzene, ethylbenzene, styrene, naphthalene, anthracene, phenanthrene, pyrene, 1,3,5-triphenylbenzene, and 1,3,5-tris(4-bromophenyl)benzene was performed, and in most cases excellent separation was achieved based on a combination of molecular sieving and adsorption effects. PMID:19754060

Ahmad, Rashid; Wong-Foy, Antek G; Matzger, Adam J

2009-10-20

86

Coordination polymer of zinc based on chiral non-racemic trans-N,N?-bis-(2-hydroxy-1-naphthalidehydene)-(1R,2R)-cyclohexa-nediamine: Synthesis, crystal structure, novel coordinational models and anticancer activity  

Microsoft Academic Search

Chiral Schiff base trans-N,N?-bis-(2-hydroxy-1-naphthalidehydene)-(1R,2R)-cyclohexanediamine C28H26N2O2 (H2L) and its chiral coordination polymer [Zn(H2L)Cl2]n were prepared and characterized by infrared spectroscopy, elemental analyses and single-crystal X-ray diffraction analysis. X-ray crystallography showed that the proton transfer of phenolic hydroxyl occurred in the chiral ligand and the complex. The chiral ligand demonstrates a one-dimensional helix chain. The Zn(II) ion is four-coordinated by two oxygen

Shuangyu Bi; Aidong Wang; Caifeng Bi; Yuhua Fan; Yan Xiao; Shanbin Liu; Qiang Wang

87

Lanthanide-polyphosphonate coordination polymers combining catalytic and photoluminescence properties.  

PubMed

A rapid, mild and high-yield microwave synthesis of 1D isotypical [Ln(H4bmt)(H5bmt)(H2O)2]3H2O coordination polymers is presented. The La(3+)-based material is highly active as a heterogeneous catalyst in the methanolysis of styrene oxide at nearly room temperature. Eu(3+)- and Tb(3+)-doped materials are very effective UV-to-visible light converters. PMID:23752868

Vilela, Srgio M F; Firmino, Ana D G; Mendes, Ricardo F; Fernandes, Jos A; Ananias, Duarte; Valente, Anabela A; Ott, Holger; Carlos, Lus D; Rocha, Joo; Tom, Joo P C; Paz, Filipe A Almeida

2013-07-21

88

Increased dimensionalities of zinc-diphenic acid coordination polymers by simultaneous or subsequent addition of neutral bridging ligands.  

PubMed

Three coordination polymers containing zinc and diphenic acid (H2dpa) were synthesised by solvothermal reaction. Zn(dpa)(H2O) is a one-dimensional coordination polymer that consists of parallel ladder-like chains. One carboxylate group of the diphenic acid coordinates two zinc atoms forming a dinuclear unit which composes the steps of the ladder. The other carboxylate connects to a zinc atom in the next step of the ladder. The fourth coordination site at the zinc atom is occupied by water. Attempts to crosslink the chains by replacing the water molecule with the neutral ligands triethylenediamine (dabco) or 4,4'-bipyridyl lead to the compounds Zn2(dpa)2(dabco) and Zn(dpa)(4,4'-bpy). Their structures can be rationalised as being derived from action of the neutral ligand on Zn(dpa)(H2O), and while they are most conveniently prepared in a one-pot synthesis, it is also possible to obtain them by exposing Zn(dpa)(H2O) to the respective neutral ligand. Zn2(dpa)2(dabco) is a layered two-dimensional coordination polymer in which dinculear zinc carboxylate paddle wheel units and the dabco ligand form infinite linear chains. The chains are interconnected by the dpa unit. The structure of Zn(dpa)(4,4'-bpy) consists of two identical interpenetrating three-dimensional networks. In the network, helical Zn(dpa) chains are interconnected by the rigid 4,4'-bipyridine ligand. Thermogravimetric analysis indicates a high thermal stability of this coordination polymer with decomposition occurring in the range 350-450 degrees C. This is complemented by X-ray thermodiffractometry that indicates a phase transition at 337 degrees C and the final loss of crystallinity at 427 degrees C. The room temperature phase expands drastically along one axis and contracts along the other two axes on heating. PMID:16402145

Dietzel, Pascal D C; Blom, Richard; Fjellvg, Helmer

2005-10-27

89

A one-dimensional coordination polymer of 5-[(imidazol-1-yl)methyl]benzene-1,3-dicarboxylic acid with Cu(II) cations.  

PubMed

5-[(Imidazol-1-yl)methyl]benzene-1,3-dicarboxylic acid (H2L) was synthesized and the dimethylformamide- and dimethylacetamide-solvated structures of its adducts with Cu(II), namely catena-poly[[copper(II)-bis[?-3-carboxy-5-[(imidazol-1-yl)methyl]benzoato

Patra, Ranjan; Goldberg, Israel

2013-03-06

90

Interactive simulation of one-dimensional flexible parts  

Microsoft Academic Search

In this paper, we present a system for simulating one dimensional flexible parts such as cables or hoses. The modeling of bending and torsion follows the Cosserat model. For this purpose we use a generalized spring-mass system and describe its configuration by a care- fully chosen set of coordinates. Gravity and contact forces as well as the forces responsible for

Johannes Gutenberg

91

Self-assembly of Two Cobalt(II) Coordination Polymers with 1,2,4,5-benzenetetracarboxylate and 1,3-bi(4-pyridyl)propane Ligands  

Microsoft Academic Search

Two cobalt(II) coordination polymers [Co(H2O)2(H2btec) (bpp)2]n (1) and {[Co2(H2O)4(bpp)3(btec)] 4H2O}n (2) were synthesized under ambient conditions with 1,2,4,5-benzenetetracarboxylic acid (btec) and 1,3-bi(4-pyridyl)propane (bpp) as mixed ligands. Complex 1 is characteristic of one-dimensional chains bridged by H2btec ligands, the terminal bpp ligands complete the coordination sphere of the cobalt atoms and are further hydrogen-bonded to neighboring chains via OH

Ying-Tao Ren; Yin-Xue Zhi; Jun Hu; Yue-Qing Zheng

2010-01-01

92

Porous coordination polymer with flexibility imparted by coordinatively changeable lithium ions on the pore surface.  

PubMed

Solvothermal reactions of equimolar zinc acetate, lithium acetate, and 1,3,5-benzenetricarboxylic acid (H(3)btc) in different mixed solvents yielded isostructural three-dimensional frameworks [LiZn(btc)(cG)].lG [cG and lG denote coordinated and lattice guests, respectively; cG = (nmp)(0.5)(H(2)O)(0.5), lG = (EtOH)(0.5) (1a); cG = H(2)O, lG = EtOH (1b); nmp = N-methyl-2-pyrrolidone] with one-dimensional channels occupied by guest molecules and solvent-coordinated, extrusive Li(+) ions. Thermogravimetry analyses and powder X-ray diffraction measurements revealed that both 1a and 1b can lose all lattice and coordinated guests to form a desolvated phase [LiZn(btc)] (MCF-27, 1) and almost retains the original framework structure. Gas adsorption measurements on 1 confirmed its permanent porosity but suggested a structural transformation from 1a/1b to 1. It is noteworthy that only 1a can undergo a single-crystal to single-crystal (SCSC) transformation into 1 upon desolvation. The crystal structure of 1 revealed that the Li(+) ions were retracted into the channel walls via complementary coordination to the carboxylate oxygen atoms in the framework rather than being exposed on the pore surface. Single-crystal X-ray diffraction analyses were also performed for N(2)- and CO(2)-loaded samples of 1, revealing that the framework remained unchanged when the gases were adsorbed. Although the gas molecules could not be modeled, the residue electrons inside the channels demonstrated that the retracted Li(+) ions still behave as the primary interacting site for CO(2) molecules. Nevertheless, solvent molecules such as H(2)O can readily compete with the framework oxygen atom to retrieve the extrusive Li(+) ions, accompanying the reverse structural transformation, i.e., from 1 to 1a/1b. PMID:20050697

Xie, Lin-Hua; Lin, Jian-Bin; Liu, Xiao-Min; Wang, Yu; Zhang, Wei-Xiong; Zhang, Jie-Peng; Chen, Xiao-Ming

2010-02-01

93

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

SciTech Connect

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)(H{sub 2}O){sub 2}]{sub n} (3), [Cu(cbop){sub 2}(4,4 Prime -bipy)(H{sub 2}O)]{sub n} (4) (cbop=(S)-N-(4-cyanobenzoic)-5-oxoproline, 4,4 Prime -bipy=4,4 Prime -bipyridine), {l_brace}[Cu(nbop){sub 2}(4,4 Prime -bipy)]{center_dot}4H{sub 2}O{r_brace}{sub n} (5) (nbop=(S)-N-(4-nitrobenzoic)-5-oxoproline), {l_brace}[Cd(nbop){sub 2}(4,4 Prime -bipy)]{center_dot}2H{sub 2}O{r_brace}{sub n} (6), and [Ni(nbop){sub 2}(4,4 Prime -bipy)(H{sub 2}O){sub 2}]{sub 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 Prime -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. - Graphical abstract: Using aminocarboxylate derivates as chiral ligands, five new homochiral coordination polymers possessing second harmonic generation activities have been hydrothermally synthesized. Highlights: Black-Right-Pointing-Pointer Two new chiral aminocarboxylate derivates were firstly synthesized. Black-Right-Pointing-Pointer Five new homochiral metal organic complexes were obtained hydrothermally based on these ligands. Black-Right-Pointing-Pointer Intramolecular amidation was taken place on the aminocarboxylate derivates during the formation of these complexes. Black-Right-Pointing-Pointer In situ amidation may be due to the impact of 4,4 Prime -bipyridine. Black-Right-Pointing-Pointer The homochiral complexes are nonlinear optical active.

Chen Jianshan; Sheng Tianlu; Hu Shengmin; Xiang Shengchang; Fu Ruibiao; Zhu Qilong [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Wu Xintao, E-mail: wxt@fjirsm.ac.cn [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

2012-08-15

94

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

2013-03-15

95

Exactly solvable one-dimensional inhomogeneous models  

Microsoft Academic Search

We present a simple way of constructing one-dimensional inhomogeneous models (random or quasiperiodic) which can be solved exactly. We treat the example of an Ising chain in a varying magnetic field, but our procedure can easily be extended to other one-dimensional inhomogeneous models. For all the models we can construct, the free energy and its derivatives with respect to temperature

B. Derrida; J. Peyrire

1986-01-01

96

One-dimensional structures of zinc(II) and cobalt(II) coordination complexes [Zn(NCS) 2(PPz)] n and [CoCl 2(PPz)] n (PPz=piperazine)  

Microsoft Academic Search

The reaction of Zn(NO3)26H2O with PPz hexahydrate (PPz=piperazine) and NH4SCN in CH3OH afforded the complex [Zn(NCS)2(PPz)]n (1). The reaction of CoCl26H2O with PPz in CH3OH afforded the complex [CoCl2(PPz)]n (2). The PPz ligand in 1 is coordinated to the metal centers through both nitrogen atoms to form a 1-D zigzag-chain structure and the distorted tetrahedral coordination geometry at each zinc

Maw-Cherng Suen; Tai-Chiun Keng; Ju-Chun Wang

2002-01-01

97

Structure and magnetic properties of a new iron(II) citrate coordination polymer.  

PubMed

The new compound [Fe(H2cit)(H2O)]n (NICS-2) is the first neutral ferrous citrate carboxylate that has been synthesized up to now. The iron citrate coordination polymer was hydrothermally synthesized and the structure was solved using single-crystal X-ray diffraction. It crystallizes in an orthorhombic space group P212121 (No. 19), with a = 5.9470?(4), b = 10.4021?(5), c = 13.5773?(7)?, V = 839.91?(8)?(3), Z = 4. Its structure consists of one-dimensional chains of corner-sharing Fe(II)O6 octahedra that are additionally cross-linked with citrate ligands. Chains are additionally stabilized into a pseudo-three-dimensional structure by hydrogen bonds. The measurement of magnetic properties revealed that the magnetic moment is almost constant above 100?K (?eff = 5.1?B), but decreases rapidly below this temperature most probably due to the appearance of weak antiferromagnetic interactions between Fe atoms. Additionally, analysis of Mossbauer spectra confirmed the presence of divalent Fe atoms in the structure. Thermogravimetrical and X-ray high-temperature diffraction analyses showed the thermal stability of the material up to 548?K. PMID:24056358

Birsa ?eli?, Tadeja; Jagli?i?, Zvonko; Lazar, Karoly; Zabukovec Logar, Nataa

2013-09-19

98

New 4,5-dichlorophthalhydrazidate-bridged chained coordination polymers  

NASA Astrophysics Data System (ADS)

The hydrothermal self-assemblies of Pb2+/Cd2+ salt, 4,5-dichlorophthalic acid (dcpha), N2H4H2O together with 1,10-phenanthrolineH2O (phen) or 2,2?-bipyridine (bpy) generated two new monoacylhydrazidate-bridged 1-D chained coordination polymers [Pb2(DCPTH)4(phen)2] 1 and [Cd3(DCPTH)2(dcph)2(bpy)2] 2 (DCPTH=4,5-dichlorophthalhydrazidate, dcph=4,5-dichlorophthalate). The monoacylhydrazidate ligand DCPTH originated from the hydrothermal in situ acylation reaction between dcpha and N2H4H2O. In compound 1, two types of coordination modes for DCPTH are found, which link alternately the Pb(II) centers into a 1-D chain structure of compound 1 with ancillary phen molecules. In compound 2, DCPTH and dcph as the mixed bridges extend the Cd(II) centers into a 1-D chain structure of compound 2 with auxiliary bpy molecules. DCPTH in compound 2 shows a different coordination mode from those observed in compound 1.Graphical abstractBy applying the in situ acylation reaction between 4,5-diclorophthalic acid and N2H4H2O, two 4,5-dichlorophthalhydrazidate-bridged chained compounds [Pb2(DCPTH)4(phen)2] and [Cd3(DCPTH)2(dcph)2(bpy)2] (4,5-dichlorophthalhydrazidate=DCPTH, and dcph=4,5-dichlorophthalate) were hydrothermally synthesized. Display Omitted

Jin, Juan; Wu, Di; Jia, Ming-Jun; Peng, Yu; Yu, Jie-Hui; Wang, Yu-Chang; Xu, Ji-Qing

2011-03-01

99

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

100

Mechanical Properties of One-Dimensional Nanostructures  

Microsoft Academic Search

The elastic mechanical properties of one-dimensional nanostructures are considered, with an emphasis on the use of contact-resonance\\u000a atomic force microscopy methods to determine elastic moduli. Various methods used to determine elastic moduli of one-dimensional\\u000a nanostructures are reviewed before detailed consideration of the experimental and analytical methods used in contact-resonance\\u000a atomic force microscopy As direct applications of contact-resonance atomic force microscopy

Gheorghe Stan; Robert F. Cook

2010-01-01

101

New 4,5-dichlorophthalhydrazidate-bridged chained coordination polymers  

SciTech Connect

The hydrothermal self-assemblies of Pb{sup 2+}/Cd{sup 2+} salt, 4,5-dichlorophthalic acid (dcpha), N{sub 2}H{sub 4}.H{sub 2}O together with 1,10-phenanthroline.H{sub 2}O (phen) or 2,2'-bipyridine (bpy) generated two new monoacylhydrazidate-bridged 1-D chained coordination polymers [Pb{sub 2}(DCPTH){sub 4}(phen){sub 2}] 1 and [Cd{sub 3}(DCPTH){sub 2}(dcph){sub 2}(bpy){sub 2}] 2 (DCPTH=4,5-dichlorophthalhydrazidate, dcph=4,5-dichlorophthalate). The monoacylhydrazidate ligand DCPTH originated from the hydrothermal in situ acylation reaction between dcpha and N{sub 2}H{sub 4}.H{sub 2}O. In compound 1, two types of coordination modes for DCPTH are found, which link alternately the Pb(II) centers into a 1-D chain structure of compound 1 with ancillary phen molecules. In compound 2, DCPTH and dcph as the mixed bridges extend the Cd(II) centers into a 1-D chain structure of compound 2 with auxiliary bpy molecules. DCPTH in compound 2 shows a different coordination mode from those observed in compound 1. -- Graphical abstract: By applying the in situ acylation reaction between 4,5-diclorophthalic acid and N{sub 2}H{sub 4}.H{sub 2}O, two 4,5-dichlorophthalhydrazidate-bridged chained compounds [Pb{sub 2}(DCPTH){sub 4}(phen){sub 2}] and [Cd{sub 3}(DCPTH){sub 2}(dcph){sub 2}(bpy){sub 2}] (4,5-dichlorophthalhydrazidate=DCPTH, and dcph=4,5-dichlorophthalate) were hydrothermally synthesized. Display Omitted Research highlights: > In this article, we first reported the preparations and structural characterization of two examples of 4,5-dichlorophthalhydrazidate-bridged chained coordination polymers [Pb{sub 2}(DCPTH){sub 4}(phen){sub 2}] 1 and [Cd{sub 3}(DCPTH){sub 2}(dcph){sub 2}(bpy){sub 2}] 2. 4,5-dichlorophthalhydrazidate derived from the hydrothermal in situ acylation reactions between 4,5-dichlorophthalic acid and N{sub 2}H{sub 4}.H{sub 2}O. > In this article, a simple method to judge whether the polycarboxylic acid precursors have acylated into the acylhydrazidate ligands is introduced. > In this article, DFT calculations were carried out on the excited electronic states of the compounds, the fluorescence emission properties of the compounds have been better understood. > this article, by the structural characterization of the obtained monoacylhydrazidate-containing compounds, the character of the monoacylhydrazidate ligands has been further understood.

Jin, Juan [College of Chemistry and State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130023 (China); Wu, Di [State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, Jilin 130023 (China); Jia, Ming-Jun [Key Laboratory of Surface and Interface Chemistry of Jilin Province, College of Chemistry, Jilin University, Qianjin Road 2699, Changchun 130012 (China); Peng, Yu [College of Chemistry and State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130023 (China); Yu, Jie-Hui, E-mail: jiehuiyu@yahoo.com.c [College of Chemistry and State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130023 (China); State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing, Jiangsu 210093 (China); Wang, Yu-Chang [College of Chemistry and State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130023 (China); Xu, Ji-Qing, E-mail: xjq@mail.jlu.edu.c [College of Chemistry and State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130023 (China)

2011-03-15

102

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

103

Synthesis, structure, and photoluminescent properties of metal-organic coordination polymers assembled with bithiophenedicarboxylic acid.  

PubMed

Four novel metal-organic coordination polymers with the formulas Mn(3)(btdc)(3)(DMF)(4) (1), Co(btdc)(DMF)(3) (2), Zn(btdc)(DMF)(3) (3), and Zn(btdc)(4,4'-bpy)(0.5) (4), where H(2)btdc = 2,2'-bithiophene-5,5'-dicarboxylic acid, DMF = N,N'-dimethylformamide, and 4,4'-bpy = 4,4'-bipyridine, have been successfully synthesized. Crystal 1 with Mn(2+) as the cation features a three-dimensional (3D) infinite framework built from trimanganese clusters, and crystals 2 and 3 with Co(2+) and Zn(2+), respectively, as the cation both have one-dimensional zigzag polymeric coordination chains. Crystal 4 synthesized using a mixture of 4,4'-bpy and H(2)btdc exhibits a triply interpenetrating 3D framework built from a dizinc paddlewheel second building unit with a distorted primitive cubic single net. The results of UV/vis spectra indicate that metal binding does not disturb the detailed electronic structure of the ligand. We also demonstrate that Zn(2+) can greatly enhance the luminescence emission of the H(2)btdc ligand, and the emission intensity of crystal 4 is almost 20 times higher than that of the free H(2)btdc ligand. Steady-state and time-resolved spectroscopic measurement reveal that the more rigid environment of the btdc ligand can stabilize the highly excited long-lived states in metal-organic frameworks (MOFs), which thus greatly changes the emission properties of MOFs. PMID:21395253

Zhao, Jiao; Wang, Xiu-Li; Shi, Xin; Yang, Qi-Hua; Li, Can

2011-03-11

104

A framework for predicting surface areas in microporous coordination polymers.  

PubMed

A predictive tool termed the linker to metal cluster (LiMe) ratio is introduced as a method for understanding surface area in microporous coordination polymers (MCPs). Calibrated with geometric accessible surface area computations, the LiMe ratio uses molecular weight of building block components to indicate the maximum attainable surface area for a given linker and metal cluster combination. MOF-5 and HKUST-1 are used as prototypical structures to analyze MCPs with octahedral M(4)O(CO(2)R)(6) and paddlewheel M(2)(CO(2)R)(4) metal clusters. Insight into the effects of linker size, geometry, number of coordinating groups, and framework interpenetration is revealed through the LiMe ratio analysis of various MCPs. Experimental surface area deviation provides indication that a material may suffer from incomplete guest removal, structural collapse, or interpenetration. Because minimal data input are required, the LiMe ratio surface area analysis is suggested as a quick method for experimental verification as well as a guide for the design of new materials. PMID:20143886

Schnobrich, Jennifer K; Koh, Kyoungmoo; Sura, Kush N; Matzger, Adam J

2010-04-20

105

Syntheses and structures of metal tetrazole coordination polymers.  

PubMed

Two salts and seven copper(I/II) and silver(I) coordination polymers containing tetrazolyl ligands have been hydro(solvo)thermal synthesized by metal salts, NaN3 and various nitriles generated via [2 + 3] cycloaddition reactions of organonitriles and sodium azide. The study also shows that in some cases the azide can play a dual role in the in situ syntheses of metal tetrazole complexes, namely, starting material for tetrazole ligand and co-ligand in the tetrazole-based coordination complexes. Compounds and are simple salts of ammonium and sodium 5-methyltetrazolate. Compound has a 3-D framework with intersecting channel and unprecedented (4(9).6(6)) topology constructed from mixed-valent Cu8 clusters. Compounds and are isomorphous, and have 3-D organic-inorganic frameworks constructed by [M2(mtta)]+ (Hmtta = 5-methyltetrazole) ribbon and [M2(N3)]+ (M = Cu, Ag) layer two types of structural motifs, which contains an mu(4)-1,1,1,3 azide. Compound is a 3-D four-connected chiral complex with (4(2).8(4))(Cu)(4(2).8(2).10(2))(tta) topology. The structure of consists of 2-D three-connected layers that are linked by ligand-unsupported Ag(I)...Ag(I) interactions to form a 3-D supramolecular array. Compound shows a 3-D chiral framework containing tetrahedrally and linearly coordinated Ag(I) ions and mu3- and mu4-two types of 5-propyltetrazolate. Compound has a 2-D layered structure formed by linkage of [Ag(tetrazolyl)] ribbons via C-C and N-Ag bonds. Magnetic measurement confirmed that there are two Cu(II) ions and six Cu(I) ions per Cu8 unit consistent with a mixed-valent Cu(I,II) complex. PMID:16802034

Zhang, Xian-Ming; Zhao, Yan-Fei; Wu, Hai-Shun; Batten, Stuart R; Ng, Seik Weng

2006-04-06

106

One-dimensional Gromov minimal filling problem  

NASA Astrophysics Data System (ADS)

The paper is devoted to a new branch in the theory of one-dimensional variational problems with branching extremals, the investigation of one-dimensional minimal fillings introduced by the authors. On the one hand, this problem is a one-dimensional version of a generalization of Gromov's minimal fillings problem to the case of stratified manifolds. On the other hand, this problem is interesting in itself and also can be considered as a generalization of another classical problem, the Steiner problem on the construction of a shortest network connecting a given set of terminals. Besides the statement of the problem, we discuss several properties of the minimal fillings and state several conjectures. Bibliography: 38 titles.

Ivanov, Alexandr O.; Tuzhilin, Alexey A.

2012-05-01

107

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

108

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

109

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

2012-03-14

110

Solid-state aggregation of metallacyclophane-based Mn(II)Cu(II) one-dimensional ladders.  

PubMed

Two distinct one-dimensional (1) and two-dimensional (2) mixed-metal-organic polymers have been synthesized by using the "complex-as-ligand" strategy. The structure of 1 consists of isolated ladderlike Mn(II)(2)Cu(II)(2) chains separated from each other by neutral Mn(II)(2) dimers, whereas 2 possesses an overall corrugated layer structure built from additional coordinative interactions between adjacent Mn(II)(2)Cu(II)(2) ladders. Interestingly, 1 and 2 show overall ferri- and antiferromagnetic behavior, respectively, as a result of their distinct crystalline aggregation in the solid state. PMID:22708797

Ferrando-Soria, Jess; Grancha, Thais; Pasn, Jorge; Ruiz-Prez, Catalina; Caadillas-Delgado, Laura; Journaux, Yves; Julve, Miguel; Cano, Joan; Lloret, Francesc; Pardo, Emilio

2012-06-18

111

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

112

Haptic interaction with one-dimensional structures  

Microsoft Academic Search

One-dimensional structures are very important for simulating a variety of slender objects such as ropes, hair, wires, cables or tubes. Because of their practical relevance, an increasing number of dynamic simulation methods have been proposed during the last years. However, interaction techniques have not followed this evolution. Hence, we propose to combine the recent advances in the computation of physically

Ugo Bonanni; Petr Kmoch; Nadia Magnenat-thalmann

2009-01-01

113

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

114

The One-Dimensional Heat Equation  

NSDL National Science Digital Library

Created by Lang Moore for the Connected Curriculum Project, the purpose of this module is to study the symbolic form and graphical representation of the approximate solutions of the one-dimensional heat equation with various boundary and initial conditions. This is one within a much larger set of learning modules hosted by Duke University.

Moore, Lang

2010-05-03

115

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

116

One-dimensional bigyrotropic magnetic photonic crystals  

NASA Astrophysics Data System (ADS)

Electromagnetic wave propagation in a one-dimensional magnetic photonic crystal (MPC) made of bigyrotropic magnetic yttrium-iron garnet and nonmagnetic gadolinium-gallium garnet is theoretically investigated using the 44 transfer matrix method. Band gaps in the electromagnetic spectrum are numerically obtained and appear to depend on the helicity and direction of light propagation through the MPC.

Lyubchanskii, I. L.; Dadoenkova, N. N.; Lyubchanskii, M. I.; Shapovalov, E. A.; Lakhtakia, A.; Rasing, Th.

2004-12-01

117

Nanoscale coordination polymers exhibiting luminescence properties and NMR relaxivity  

NASA Astrophysics Data System (ADS)

This article presents the first example of ultra-small (3-4 nm) magneto-luminescent cyano-bridged coordination polymer nanoparticles Ln0.333+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 Ln0.333+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.This article presents the first example of ultra-small (3-4 nm) magneto-luminescent cyano-bridged coordination polymer nanoparticles Ln0.333+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 Ln0.333+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. Electronic supplementary information (ESI) available: TEM images and size distribution histograms, IR and emission spectra, diffraction pattern and HRTEM coupled EDX analysis. See DOI: 10.1039/c0nr00709a

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

2011-03-01

118

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

119

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 materials 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

120

Functional One-Dimensional Lipid Bilayers on Carbon Nanotube Templates  

SciTech Connect

We present one-dimensional (1-D) lipid bilayer structures that integrate carbon nanotubes with a key biological environment-phospholipid membrane. Our structures consist of lipid bilayers wrapped around carbon nanotubes modified with a hydrophilic polymer cushion layer. Despite high bilayer curvature, the lipid membrane maintains its fluidity and can sustain repeated damage-recovery cycles. We also present the first evidence of spontaneous insertion of pore-forming proteins into 1-D lipid bilayers. These structures could lead to the development of new classes of biosensors and bioelectronic devices.

Artyukhin, A; Shestakov, A; Harper, J; Bakajin, O; Stroeve, P; Noy, A

2004-07-23

121

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

2012-11-02

122

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

2013-04-19

123

Different geometrical arrangements in carboxylate coordination polymers of flexible dicarboxylic acid  

SciTech Connect

Dicarboxylate coordination polymers (1-5) of Mn(II), Ni(II), Cu(II), Zn(II) and Cd(II), respectively, derived from (7-carboxymethoxy-naphthalen-2-yloxy)-acetic acid (L{sub 1}H{sub 2}) are synthesized and characterized. Depending on the coordination sites around the metal centers and coordination mode of the ligand, dimensionality of these polymers varies. The dicarboxylates adopt three spatial orientations: in-plane linear coordination, out-of-plane cis coordination and out-of-plane trans coordination mode. Both the cis and trans out-of-plane coordination modes are found to exist only if the ancillary ligand pyridine is coordinated to the metal ion. When the aquoligand coordinates the in-plane linear coordination mode of L{sub 1} predominates. The coordination polymers 4 and 5 show photoluminescence in solution. The dicarboxylate of (5-carboxymethoxy-naphthalen-1-yloxy)-acetic acid (L{sub 2}H{sub 2}) does not form coordination polymer under ambient conditions, but prefers to remain as uncoordinated anion providing hydrophobic confinement to hexa-aquometal(II) cation. Compound 3 crystallizes in P2{sub 1} space group and it shows broadband ultra-violet fluorescence centered at 352.9 nm on focusing 632.8 nm He:Ne laser. - Graphical abstract: Different geometrical arrangements in coordination polymers derived from (7-carboxymethoxy-naphthalen-2-yloxy)-acetic acid of metal ions Mn(II), Ni(II), Cu(II), Zn(II) and Cd(II) are presented. The (5-carboxymethoxy-naphthalen-1-yloxy)-acetic acid led to hexa-aquo cadmium(II) dicarboxylate. Highlights: > Structural and spectroscopic characterizations of five dicarboxylate coordination polymers of (7-carboxymethoxy-naphthalen-2-yloxy)-acetic acid with different metal ions are presented. > Different geometrical arrangements of coordination polymers stabilized in solid state are described. > Photoluminescence properties of the polymers are shown. > NLO property of a copper coordination polymer is described.

Deka, Himangshu; Sarma, Rupam [Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781 039, Assam (India); Kumari, Satchi; Khare, Alika [Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781 039, Assam (India); Baruah, Jubaraj B., E-mail: juba@iitg.ernet.in [Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781 039, Assam (India)

2011-07-15

124

A novel 1D silver(I) coordination polymer constructed from indol-3-butyric acid: Synthesis, crystal structure and natural bond orbital analysis by DFT  

NASA Astrophysics Data System (ADS)

A novel one-dimensional Ag(I) coordination polymer with formula [Ag(IBA)]n(1) (IBA = indol-3-butyric acid) has been synthesized and structurally characterized by infrared spectroscopy (IR), elemental analysis and single crystal X-ray diffraction techniques. X-ray crystallographic study revealed that 1 crystallizes in monoclinic space group C2/c with unit cell parameters of a = 25.6863(7) , b = 7.5837(2) , c = 10.9065(3) , ? = 103.296(2), V = 2067.61(10) 3 and shows 1D wave-like one-dimensional coordination polymer. In the crystal structure, 1D chains are formed by Ag2:L2 dimers connected by argentophilic Ag⋯Ag interactions. The adjacent 1D polymeric chains are further assembled by hydrogen bond (NH⋯O), Ag⋯C, Ag⋯?, CH⋯? and weak ?⋯? interactions into a three-dimensional framework. The complex also exhibits the intermolecular pseudo-agostic (IPA) interaction (C-H⋯Ag). The spontaneous formation of the 1D assembly of complex 1 was investigated with density functional theory (DFT) method.

Zorlu, Yunus; Can, Hatice

2013-04-01

125

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

126

Quasi-one-dimensional scattering in a discrete model  

SciTech Connect

We study quasi-one-dimensional scattering of one and two particles with short-range interactions on a discrete lattice model in two dimensions. One of the directions is tightly confined by an arbitrary trapping potential. We obtain the collisional properties of these systems both at finite and zero Bloch quasimomenta, considering as well finite sizes and transversal traps that support a continuum of states. This is made straightforward by using the exact ansatz for the quasi-one-dimensional states from the beginning. In the more interesting case of genuine two-particle scattering, we find that more than one confinement-induced resonances appear due to the nonseparability of the center-of-mass and relative coordinates on the lattice. This is done by solving its corresponding Lippmann-Schwinger-like equation. We characterize the effective one-dimensional interaction and compare it with a model that includes only the effect of the dominant, broadest resonance, which amounts to a single-pole approximation for the interaction coupling constant.

Valiente, Manuel; Moelmer, Klaus [Lundbeck Foundation Theoretical Center for Quantum System Research, Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark)

2011-11-15

127

Quasi-one-dimensional scattering in a discrete model  

NASA Astrophysics Data System (ADS)

We study quasi-one-dimensional scattering of one and two particles with short-range interactions on a discrete lattice model in two dimensions. One of the directions is tightly confined by an arbitrary trapping potential. We obtain the collisional properties of these systems both at finite and zero Bloch quasimomenta, considering as well finite sizes and transversal traps that support a continuum of states. This is made straightforward by using the exact ansatz for the quasi-one-dimensional states from the beginning. In the more interesting case of genuine two-particle scattering, we find that more than one confinement-induced resonances appear due to the nonseparability of the center-of-mass and relative coordinates on the lattice. This is done by solving its corresponding Lippmann-Schwinger-like equation. We characterize the effective one-dimensional interaction and compare it with a model that includes only the effect of the dominant, broadest resonance, which amounts to a single-pole approximation for the interaction coupling constant.

Valiente, Manuel; Mlmer, Klaus

2011-11-01

128

Tuning the entanglement of coordination polymers by controlling the steric hindrance of organic linkers  

NASA Astrophysics Data System (ADS)

Two entangled coordination polymers have been synthesized and characterized.The ligands' steric hindrance to the formation of entangled framework was evaluated.The luminescent properties of these compounds were investigated at room temperature.

Guo, Xianmin; Guo, Huadong; Zou, Hengye; Qi, Yanjuan; Liu, Chunming

2013-07-01

129

One dimensional-two phase particulate flow  

SciTech Connect

A computer model, originally developed by Crowe at Washington State University, which predicts the velocity of solid particles entrained in a one-dimensional gas stream, is modified to improve its accuracy and extend the range of velocity prediction. The program is also used to demonstrate the effects that initial particle velocity and particle concentration have on velocity predictions. The accuracy of the model is confirmed by comparing the theoretical predictions with experimentally measured velocities of particles varying in size, shape and density. For all cases where test data could be measured accurately, the theoretical predictions are shown to be in good agreement with the average experimental values.

Kleist, D.M.

1977-09-01

130

One-dimensional model for mud flows  

NASA Astrophysics Data System (ADS)

A transient, one-dimensional model for dynamic flood routing of mud flows is presented. The governing equations of mass and momentum conservation incorporate laminar flow resistance effects and utilize a power law expression to represent the cross-sectional geometry of the channel. The equations are solved by the method of characteristics on fixed time lines and program execution is performed on a micro-computer. Numerical results are compared with published experimental data for a laminar flow, dambreak problem of a viscous oil.

Schamber, D. R.; MacArthur, R. C.

1985-10-01

131

A one-dimensional tunable magnetic metamaterial  

NASA Astrophysics Data System (ADS)

We present experimental data on a one-dimensional superconducting 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 SQUIDs. In order to obtain the effective magnetic permeability from the measured data, we employ a technique that uses only the complex transmission coefficient S21.

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

2013-09-01

132

Bosonizing one-dimensional cold atomic gases  

NASA Astrophysics Data System (ADS)

We present results for the long-distance asymptotics of correlation functions of mesoscopic one-dimensional systems with periodic and open (Dirichlet) boundary conditions, as well as at finite temperature in the thermodynamic limit. The results are obtained using Haldane's harmonic-fluid approach (also known as 'bosonization'), and are valid for both bosons and fermions, in weakly and strongly interacting regimes. The harmonic-fluid approach and the method of computing the correlation functions using conformal transformations are explained in great detail. As an application relevant to one-dimensional systems of cold atomic gases, we consider the model of bosons interacting with a zero-range potential. The Luttinger-liquid parameters are obtained from the exact solution by solving the Bethe-ansatz equations in finite-size systems. The range of applicability of the approach is discussed, and the prefactor of the one-body density matrix of bosons is fixed by finding an appropriate parametrization of the weak-coupling result. The formula thus obtained is shown to be accurate, when compared with recent diffusion Monte Carlo calculations, within less than 10%. The experimental implications of these results for Bragg scattering experiments at low and high momenta are also discussed.

Cazalilla, M. A.

2004-04-01

133

Determination of tetracycline in milk by using nucleotide/lanthanide coordination polymer-based ternary complex.  

PubMed

The meta-organic coordination polymers have been emerged as fascinating nanomaterials because of their tunable nature. In this work, we employed lanthanide coordination polymer self-assembled from adenosine monophosphate (AMP) and europium ion (Eu(3+)) as receptor reagent and citrate (Cit) as ancillary ligand to construct a fluorescent sensor for the detection of tetracycline (Tc) in milk. The co-coordination of Cit and Tc with Eu(3+) on the surface of the coordination polymer AMP/Eu leads to the formation of ternary complex which emitted strong fluorescence due to the removal of coordinated water molecules and an intramolecular energy transfer from Tc to Eu(3+). The fluorescent intensity of Eu(3+) displayed a good linear response to Tc concentrations in the range of 0.1-20?M with a detection limit of 60nM. This method was successfully applied to determine the levels of Tc in milk, which is the first application of coordination polymer as a fluorescent sensor in real sample. Compared with other Eu(3+)-based fluorescent methods for Tc detection, the presented method allows simple, direct analysis of Tc without requiring special reaction media or complicated prepreparation processes. This straightforward strategy could be extended to the preparation of other lanthanide coordination polymer-based fluorescent probes for applications in biosensing, imaging, drug delivery, and so on. PMID:23907076

Tan, Hongliang; Ma, Chanjiao; Song, Yonghai; Xu, Fugang; Chen, Shouhui; Wang, Li

2013-07-17

134

One-dimensional Van Hove polaritons  

NASA Astrophysics Data System (ADS)

We study the light-matter coupling of microcavity photons and an interband transition in a one-dimensional (1D) nanowire. Due to the Van Hove singularity in the density of states, resulting in a resonant character of the absorption line, the achievement of strong coupling becomes possible even without the formation of a bound state of an electron and a hole. The calculated absorption in the system and corresponding energy spectrum reveal anticrossing behavior characteristic of the formation of polariton modes. In contrast to the case of conventional exciton polaritons, the formation of 1D Van Hove polaritons will not be restricted to low temperatures and can be realized in any system with a singularity in the density of states.

Arnardottir, K. B.; Kyriienko, O.; Portnoi, M. E.; Shelykh, I. A.

2013-03-01

135

One-dimensional dynamic microslip friction model  

NASA Astrophysics Data System (ADS)

A one-dimensional dynamic microslip friction model, including the damper inertia, is presented in this paper. An analytical approach is developed to obtain the steady-state solution of the resulting nonlinear partial differential equations when subjected to harmonic excitation. In the proposed approach, according to the excitation frequency, a single mode of the system is considered in the steady-state solution for simplicity; consequently, phase difference among spatially distributed points is neglected. Three types of normal load distributions, resulting in distinct stick slip transitions along the contact interface, are studied. The resulting hysteresis curves and the associated Fourier coefficients are obtained and compared with each other. An equivalent point contact friction model is established and compared with the proposed microslip model, illustrating the effects of partial slip in the contact interface for low amplitude or high normal load applications.

Cigeroglu, Ender; Lu, Wangming; Menq, Chia-Hsiang

2006-05-01

136

One dimensional M5-brane intersections  

SciTech Connect

We study one-dimensional intersections of M5 branes with M5 and M2 branes. On the worldvolume of the M5-brane, such an intersection appears as a string soliton. We study this worldvolume theory in two different regimes: (1) Where the world-volume theory is formulated in flat space and (2) where the world-volume theory is studied in the supergravity background produced by a stack of M5 (or M2) branes. In both cases, we study the corresponding string solitons, and find the most general BPS configuration consistent with the fraction of supersymmetries preserved. We argue that M5 and M2 brane intersections leave different imprints on the world-volume theory of the intersecting probe brane, although geometrically they appear to be similar.

Fayyazuddin, Ansar [Department of Physics and Astronomy, Tufts University, Medford, Massachusetts 02155 (United States); Department of Physics, Stockholm University, Box 6730, S-113 85 Stockholm (Sweden); Husain, Tasneem Zehra [Department of Physics, Stockholm University, Box 6730, S-113 85 Stockholm (Sweden); Jefferson Physical Laboratory, Harvard University, Cambridge, Massachusetts (United States); Jatkar, Dileep P. [Jefferson Physical Laboratory, Harvard University, Cambridge, Massachusetts (United States); Harish-Chandra Research Institute, Chhatnag Road, Jhusi, Allahabad, 211019 (India)

2005-05-15

137

Aperiodicity in one-dimensional cellular automata  

SciTech Connect

Cellular automata are a class of mathematical systems characterized by discreteness (in space, time, and state values), determinism, and local interaction. A certain class of one-dimensional, binary site-valued, nearest-neighbor automata is shown to generate infinitely many aperiodic temporal sequences from arbitrary finite initial conditions on an infinite lattice. The class of automaton rules that generate aperiodic temporal sequences are characterized by a particular form of injectivity in their interaction rules. Included are the nontrivial linear'' automaton rules (that is, rules for which the superposition principle holds); certain nonlinear automata that retain injectivity properties similar to those of linear automata; and a wider subset of nonlinear automata whose interaction rules satisfy a weaker form of injectivity together with certain symmetry conditions. A technique is outlined here that maps this last set of automata onto a linear automaton, and thereby establishes the aperiodicity of their temporal sequences. 12 refs., 3 figs.

Jen, E.

1990-01-01

138

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 S21. PMID:24104143

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

2013-09-23

139

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

140

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

141

Neutron scattering from a coordination polymer quantum paramagnet  

NASA Astrophysics Data System (ADS)

Inelastic neutron scattering measurements are reported for a powder sample of the spin- 1/2 quantum paramagnet Cu(quinoxaline)Br2 . Magnetic neutron scattering is identified above an energy gap of 1.9meV . Analysis of the sharp spectral maximum at the onset indicates that the material is magnetically quasi-one-dimensional. Consideration of the wave vector dependence of the scattering and polymeric structure further identifies the material as a two-legged spin- 1/2 ladder. Detailed comparisons of the data to various models of magnetism in this material based on the single-mode approximation and the continuous unitary transformation are presented. The latter theory provides an excellent account of the data with leg exchange J?=2.0meV and rung exchange J?=3.3meV .

Hong, T.; Kenzelmann, M.; Turnbull, M. M.; Landee, C. P.; Lewis, B. D.; Schmidt, K. P.; Uhrig, G. S.; Qiu, Y.; Broholm, C.; Reich, D.

2006-09-01

142

Local li coordination and ionic transport in methacrylate-based gel polymer electrolytes.  

PubMed

The local Li cation coordination motifs and the interactions between the hosting methacrylate-based polymer membrane and the liquid electrolyte [1?M LiPF6 in ethylene carbonate (EC)/dimethyl carbonate (DMC)] are studied by employing liquid and solid-state NMR spectroscopy. At low temperatures, two different coordination modes for Li cations are identified with the help of dipolar-based solid-state NMR techniques, one of which is the exclusive coordination by DMC molecules, while the other is a co-coordination by the polymer and DMC molecules. At room temperature, Li cations are found to be extremely mobile, coordinated by EC and DMC molecules as well as the copolymer, as found by liquid-state NMR spectroscopy. PMID:23959813

Voigt, Nadine; Isken, Philipp; Lex-Balducci, Alexandra; van Wllen, Leo

2013-08-20

143

Luttinger Theorem in One Dimensional Metals  

NASA Astrophysics Data System (ADS)

In one dimension (1D), the low energy physics is described by the Luttinger Liquid Theory (LLT). One of the characterizing features of the LLT is that the one-particle Green's function has a branch cut singularity instead of simple pole. Spin and charge are separated and propagate with different velocities. Experimentally, 1D physics have been observed in the quasi-one dimensional organic conductors. Recent proposals suggest that the essential physics of the high temperature superconducting cooper-oxides is a two dimensional version of the 1D LLT. In 1960 Luttinger proved a theorem, using a Fermi-like Green's function, stating that the volume of the Fermi surface is unchanged when the interactions are turned on and that the momentum distribution function has a discontinuity at the Fermi momentum of the noninteracting system. We show how this theorem is modified in a generic 1D model, namely the Tomonaga-Luttinger model and demonstrate the validity of the generalized version of the theorem. We discuss the implications for the high temperature superconductors.

Blagoev, Krastan B.; Bedell, Kevin S.

1997-03-01

144

Curly-curly, loop-loop: homoleptic metal(ii) complexes of pyridinecarbaldehyde 4'-(2,2':6',2''-terpyridyl)hydrazones and their coordination polymers.  

PubMed

The ligands 4-, 3- and 2-pyridinecarbaldehyde 4'-(2,2':6',2''-terpyridyl)hydrazone (, and ) have been prepared and characterized. In the homoleptic iron(ii) and ruthenium(ii) complexes, the nitrogen donor atoms of the pendant pyridine rings subtend an obtuse angle ( approximately 155 degrees ) at the metal centre, thus providing an expanded ligand, which can be used for the assembly one-dimensional coordination polymers with an undulating backbone. Protonation of the pendant pyridine rings in [FeL(2)](2+) (L = , , ) or [RuL(2)](2+) (L = , ) leads to a colour change from purple to blue, or red to pink, respectively, as the MLCT band shifts to a lower energy. The structural data for [Fe(H)()][PF(6)](3).3.5MeCN.2.5H(2)O (where [H](+) is the monoprotonated ligand) show that the [Fe(H)()](3+) cations form one-dimensional chains supported by N(py)HN(py) hydrogen bonds and that the undulating chains pack to give a porous material, with channels that accommodate the anions and solvent molecules. A single-crystal X-ray diffraction determination of {[Fe(NCS)(2)(Ru()(2))(2)][Fe(2)(NCS)(6)(OEt)(2)(EtOH)(2)][NCS](2).4EtOH.H(2)O}(n) reveals that pairs of [Ru()(2)](2+) cations connect {Fe(NCS)(2)} units to give a one-dimensional polymer comprising of linked metallamacrocycles. PMID:19153622

Beves, Jonathon E; Constable, Edwin C; Housecroft, Catherine E; Kepert, Cameron J; Neuburger, Markus; Price, David J; Schaffner, Silvia; Zampese, Jennifer A

2008-10-16

145

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

PubMed Central

Three novel zinc coordination polymers (NH4)n[Zn(Hida)Cl2]n (1), [Zn(ida)(H2O)2]n (2), [Zn(Hida)2]n4nH2O (3) (H2ida = iminodiacetic acid) and a monomeric complex [Zn(ida)(phen)(H2O)]2H2O (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 ?-? stacking. Interestingly, cyclic nonplanar tetrameric water clusters are observed that encapsulated in the 3-D lattice of 4. Based on 1H and 13C NMR observations, there is obvious coordination of complex 2 in solution, while 1 and 3 decompose into free iminodiacetate ligand. Monomer [Zn(ida)(H2O)3] (5) is considered as a possible discrete species from 2. These coordination polymers can serve as good molecular precursors for zinc oxide.

Ni, Lu-Bin; Zhang, Rong-Hua; Liu, Qiong-Xin; Xia, Wen-Sheng; Wang, Hongxin; Zhou, Zhao-Hui

2009-01-01

146

Tuning the self-assembly and luminescence properties of lanthanide coordination polymers by ligand design.  

PubMed

Two new structure-related tripodal ligands featuring salicylamide pendant arms, 1,3,5-tris{[(2'-furfurylaminoformyl)phenoxyl]methyl}-2,4,6-trimethylbenzene (L(I)) and 1,1,1-tris{[(2'-furfurylaminoformyl)phenoxyl]methyl}ethane (L(II)) have been designed and synthesized with the ultimate aim of self-assembling lanthanide polymers with interesting luminescent properties. Among two series of Ln(III) nitrate complexes (Ln = Pr, Nd, Sm, Eu, Gd, Tb or Dy) which have been characterized by elemental analyses, XRD, TGA and IR spectra, three new coordination polymers have been determined by X-ray diffraction analysis. The coordination polymer type {[Ln(NO(3))(3)(L(I))].nH(2)O}(n) possesses an unusual ladderlike double chain which can be further connected through pi-pi stacking interactions constructing a three-dimensional supramolecular structure. In contrast, the coordination polymer type {[Ln(NO(3))(3)(L(II))].nCH(3)OH}(n) displays a (3,3)-connected puckered two-dimensional net with 4.8(2) topological notation. The photophysical properties of the Sm, Eu, Tb and Dy complexes at room temperature are investigated. The present work substantiates the claim that the supramolecular structure as well as the luminescent properties of the coordination polymer can be tuned by varying either the backbone group or the terminal group of the organic ligand. PMID:18594707

Song, Xue-Qin; Liu, Wei-Sheng; Dou, Wei; Zheng, Jiang-Rong; Tang, Xiao-Liang; Zhang, Hong-Rui; Wang, Da-Qi

2008-05-09

147

[Ni(HF2)(3-Clpy)4]BF4 (py = pyridine): evidence for spin exchange along strongly distorted FHF- bridges in a one-dimensional polymeric chain.  

PubMed

[Ni(HF(2))(3-Clpy)(4)]BF(4) (py = pyridine) is a simple one-dimensional (1D) coordination polymer composed of compressed NiN(4)F(2) octahedra that form chains with bridging HF(2)(-) ligands. In spite of significant distortion of the HF(2)(-) bridge, a quasi-1D antiferromagnetic (AFM) behavior was observed with J(FHF) = 4.86 K. PMID:22746404

Manson, Jamie L; Baldwin, Adora G; Scott, Brian L; Bendix, Jesper; Del Sesto, Rico E; Goddard, Paul A; Kohama, Yoshimitsu; Tran, Hope E; Ghannadzadeh, Saman; Singleton, John; Lancaster, Tom; Mller, Johannes S; Blundell, Stephen J; Pratt, Francis L; Zapf, Vivien S; Kang, Jinhee; Lee, Changhoon; Whangbo, Myung-Hwan; Baines, Christopher

2012-06-29

148

"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

2013-05-21

149

A one-dimensional organic-inorganic hybrid based on the bimolecular {l_brace}[Cu(en)][CuSiWO]{r_brace}⁸⁻ polyoxometalate  

Microsoft Academic Search

A one-dimensional coordination polymer [Cu(en)][Cu(en)(HO)]{l_brace}[Cu(en)][CuSiWO]{r_brace}.4.5HO (en=ethylenediamine), which represents the first example of one-dimensional organic-inorganic hybrid based on the bimolecular Keggin polyoxometalates {l_brace}[Cu(en)][CuSiWO]{r_brace}⁸⁻ has been hydrothermally synthesized and characterized by elemental analyses, IR, TG and single crystal X-ray diffraction. Crystal data: CHCuNO{sub 84.5}SiW, monoclinic, P2\\/c, a=18.8126(3), b=23.0896(4), c=26.0711(4) A, β=96.3790(10){sup o}, V=11254.5(3) A³, T=293(2) K; Z=4, μ=23.983 mm⁻¹, R =0.0628, wR

Wang Jingping; Du Xiaodi; Niu Jingyang

2007-01-01

150

Synthesis and crystal structure of a two-dimensional silver(I)-hexamethylenetetramine coordination polymer ( hmt )  

Microsoft Academic Search

A novel two-dimensional coordination polymer [Ag(3-hexamethylenetetramine)(H2O)](BF4) was synthesized and characterized by X-ray crystallography. It crystallized in the orthorhombic space group Pnnm with a = 15.561(7) ?, b = 10.754(5) ?, c = 6.514(3) ?, and Z = 4. Each Ag center is four-coordinated in a slightly distorted tetrahedral geometry. The structure consists of 2D wavy layers of hexagonal units; these

L.-Y. Kong; Z.-H. Zhang; W.-Y. Sun; T.-A. Okamura; N. Ueyama

2005-01-01

151

The effect of pH on the dimensionality of coordination polymers.  

PubMed

Hydrothermal reactions of simple alkaline salts or their hydroxides with 3,5-pyrazoledicarboxylic acid (H(3)pdc) yielded seven new compounds. At a lower pH level three one-dimensional structures [Ca(Hpdc)(H(2)O)(4)].2H(2)O (1), [Ca(Hpdc)(H(2)O)(4)].H(2)O (2), and [Ba(H(2)pdc)(2)(H(2)O)(4)].2H(2)O (6) were obtained by evaporation of the solutions resulting from hydro(solvo)thermal reactions of MCl(2) (M = Ca, Ba) with H(3)pdc in water (1, 6) or in water/Et(3)N (2) at 150 degrees C for 3 days. Crystal structures of 1 and 2 contain zigzag chains of metal centers bridged by a single Hpdc(2-) ligand, whereas structure 6 consists of linear chains of metal centers bridged by two H(2)pdc(-) ligands. A dimer molecule [Sr(H(3)pdc)(H(2)pdc)(2)(H(2)O)(3)](2).2(H(3)pdc).4H(2)O (4) was obtained from a similar hydrothermal reaction using Sr(ClO(4))(2).6H(2)O instead of MCl(2). This compound contains [2+2] metallomacrocycles. At higher pH levels (pH = 4-6), the three-dimensional polymers [M(Hpdc)(H(2)O)] (Ca 3, Sr 5, Ba 7 ) were isolated by reactions of MCl(2) (M = Ca, Sr, Ba) with H(3)pdc in water/Et(3)N or in M(OH)(2) (M = Ca, Sr, Ba) with H(3)pdc in water under hydro(solvo)thermal conditions (150 degrees C, 3 days). Calcium and strontium are seven- and nine-coordinated in 3 and 5, respectively; barium is nine- and ten-coordinated in 7. It was observed that the increase in pH resulted in a higher connectivity level of ligands, which in turn leads to a higher dimensionality of the crystal structures. The correlation between the structures and pH values will be discussed. Crystal data: for 1, monoclinic, space group P2(1)/n (No. 14), with a = 8.382(2), b = 12.621(3), c = 11.767(2) A, beta = 98.91(3) degrees, Z = 4; for 2, 3, and 5, monoclinic, space group P2(1)/c (No. 14), Z = 4, a = 7.711(2), b = 15.574(3), c = 9.341(2) A, beta = 96.73(3) degrees, Z = 4 (2), a = 6.616(1), b = 12.654(3), c = 8.782(2) A, beta = 103.65(3) degrees, Z = 4 (3), a = 9.213(2), b = 12.088(3), c = 6.196(2) A, beta = 98.96(3) degrees (5); for 4 and 7, triclinic, space group P1 (No. 2), with a = 11.263(2), b = 11.460(3), c = 12.904(2) A, alpha = 71.54(3), beta = 98.96(3), gamma = 89.03(3) degrees, Z = 1 (4), a = 7.107(1), b = 9.780(2), c = 11.431(2) A, alpha = 74.69(3), beta = 73.39(3), gamma = 85.29(3) degrees, Z = 2 (7); for 6, monoclinic, space group C2/c (No. 15), with a = 20.493(4), b = 6.708(1), c = 15.939(3) A, beta = 123.56(3) degrees, Z = 4. PMID:11300829

Pan, L; Frydel, T; Sander, M B; Huang, X; Li, J

2001-03-12

152

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

PubMed

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. PMID:24019475

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

2013-09-09

153

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

154

Systematic formation of multilayered core-shell microspheres through the multistep growth of coordination polymers.  

PubMed

Hybrid materials: The multistep growth of various coordination polymers has been demonstrated to induce formation of well-defined multilayered core-shell structures. Composition of these structures can be fine-tuned by altering the sequence of the multistep-growth process (see scheme). PMID:23589388

Son, Juhee; Lee, Hee Jung; Oh, Moonhyun

2013-04-15

155

Programmed crystallization via epitaxial growth and ligand replacement towards hybridizing porous coordination polymer crystals.  

PubMed

Hybridized porous coordination polymers (PCPs) are synthesized through epitaxial growth or ligand replacement. Whereas epitaxial growth on the core crystal leads to a sandwich type PCP, ligand replacement near the surface of core crystal results in a core-shell type PCP. PMID:23612878

Hirai, Kenji; Chen, Kebi; Fukushima, Tomohiro; Horike, Satoshi; Kondo, Mio; Louvain, Nicolas; Kim, Chiwon; Sakata, Yoko; Meilikhov, Mikhail; Sakata, Osami; Kitagawa, Susumu; Furukawa, Shuhei

2013-04-23

156

Heterotopic silver-NHC complexes: from coordination polymers to supramolecular assemblies.  

PubMed

New coordination polymers based on different combinations of silver atoms and pyridyl-substituted N-heterocyclic carbene moieties are described. The addition of Zn(ii) templates leads to Ag-Zn supramolecular assemblies via selective ZnN interactions; a process that can be reverted. PMID:20445922

Rubio, Miguel; Siegler, Maxime A; Spek, Anthony L; Reek, Joost N H

2010-05-05

157

A novel 2-D coordination polymer constructed from high-nuclearity waist drum-like pure Ho48 clusters.  

PubMed

A novel 2-D coordination polymer constructed from high nuclearity nanosized Ho48 clusters was synthesised and structurally characterized using single-crystal X-ray analysis. The Ho48 cluster core with a charming waist drum-like structure was templated by CO3(2-) ions, and bridged by Ho-N bonds to get a 2-D coordination polymer. PMID:23784519

Chen, Lei; Guo, Jiu-Yu; Xu, Xiao; Ju, Wei-Wei; Zhang, Deng; Zhu, Dun-Ru; Xu, Yan

2013-09-26

158

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

Garca-lvarez, Joaqun; Dez, Josefina; Vidal, Cristian; Vicent, Cristian

2013-05-15

159

Fabrication of a PANI/CPs composite material: a feasible method to enhance the photocatalytic activity of coordination polymers.  

PubMed

To improve the photocatalytic activity of a coordination polymer in the visible light region, polyaniline (PANI) was loaded onto its surface through a facile in situ chemical oxidation polymerization process. The resulting PANI loaded coordination polymer composite materials with excellent stability exhibit significantly higher photocatalytic activities than the pure coordination polymer photocatalyst on the degradation of methyl orange (MO) under visible light irradiation. This enhancement can be ascribed to the introduction of PANI on the surface of the coordination polymer, which leads to efficient separation of photogenerated electron-hole pairs as well as a significant expansion of the photoresponse region. Finally, we discussed the influence of acidity on the morphology and photocatalytic activity of the composite material. An optimal condition to obtain the PANI loaded coordination polymer composite material with excellent photocatalytic activity has been obtained. PMID:23340946

Xu, Xin-Xin; Cui, Zhong-Ping; Qi, Ji; Liu, Xiao-Xia

2013-01-22

160

Solution of One-Dimensional Problem in Nonlinear Theory of Elasticity with Structured Shock Wave. (Abstract Only).  

National Technical Information Service (NTIS)

A system of wave propagation equations through an isotropic elastic medium is formulated in Euler variables as a one-dimensional nonlinear problem of elasticity in a rectangular Cartesian system of coordinates, assuming that both the velocity function and...

A. A. Burenin Y. A. Rossikhin

1990-01-01

161

Reaction controlled assemblies of polyoxotungstates (-molybdates) and coordination polymers.  

PubMed

To investigate the influence of reaction conditions on the compound structures, five polyoxometalate (POM)-supported inorganic-organic hybrid compounds, [Cu(I)(3)(L(1))(4)][PW(12)O(40)] (1), [Cu(I)(3)(L(1))(4)][PMo(12)O(40)] (2), [Cu(I)(3)(L(1))(4)][PW(12)O(40)] (3), [Cu(I)(3)(L(1))(3)][PW(12)O(40)] (4), and [Cu(I)(3)(L(2))(3)][PMo(12)O(40)] (5) [L(1) = 1,4-bis(pyrazol-1-ylmethyl)benzene, L(2) = 4,4'-bis(pyrazol-1-ylmethyl)biphenyl], were hydrothermally synthesized by tuning the reactant species and molar ratio and reaction temperature and were characterized by elemental analysis, IR spectroscopy, PXRD, XPS, electrochemistry, SPS, and X-ray crystallography. Compounds 1 and 2 were synthesized in the isostructural state at 150 degrees C, in which L(1) ligands link Cu(I) ions, generating a cationic 2D 6(3) (hcb) skeleton {[Cu(3)(L(1))(4)](3+)}(n)-like sheet that further connects with POM anions, forming a neutral 2D (3,4)-connected network with a Schlafli symbol of (5(3))(2)(5(4);8(2)). In contrast, compound 3 was synthesized at a relatively lower reaction temperature (130 degrees C) than that for the synthesis of 1 and 2, which exhibits a similar 2D sheet-like cationic skeleton with 1 and 2. Interestingly, the POM anions do not coordinate with the cationic moieties in 3. Compounds 4 and 5 were synthesized with a relatively lower reactant molar ratio in comparison with that for the synthesis of 1-3, in which the cationic coordination moieties all present 1D chain-like structures. Compound 4 exhibits a 3D (3,4)-connected sqc74 framework with a Schlafli symbol of (6;8(2))(6(4);8;10) formed by the POM anions linking {[Cu(3)(L(1))(3)](3+)}(n) cationic chains. In comparison to 4, compound 5 shows a 3D supramolecular framework, which is formed by POM anions and {[Cu(3)(L(2))(3)](3+)}(n) cationic chains via hydrogen bonds. The structural difference of compounds 1-5 indicates that the reaction conditions perform a crucial influence on the structures of this series. The electrochemical properties of 2 and 5 and the SPS responses of 3-5 suggest that these compounds can be used as potential electrocatalytic or photocatalytic framework materials. In addition, EFISPS curves indicate that 3-5 possess the n-type semiconductor characteristic. PMID:20550186

Hou, Guangfeng; Bi, Lihua; Li, Bao; Wu, Lixin

2010-07-19

162

Multifunctionality of Organometallic Quinonoid Metal Complexes: Surface Chemistry, Coordination Polymers, and Catalysts.  

PubMed

Quinonoid metal complexes have potential applications in surface chemistry, coordination polymers, and catalysts. Although quinonoid manganese tricarbonyl complexes have been used as secondary building units (SBUs) in the formation of novel metal-organometallic coordination networks and polymers, the potentially wider applications of these versatile linkers have not yet been recognized. In this Account, we focus on these diverse new applications of quinonoid metal complexes, and report on the variety of quinonoid metal complexes that we have synthesized. Through the use of [(?(6)-hydroquinone)Mn(CO)3](+), we are able to modify the surface of Fe3O4 and FePt nanoparticles (NPs). This process occurs either by the replacement of oleylamine with neutral [(?(5)-semiquinone)Mn(CO)3] at the NP surface, or by the binding of anionic [(?(4)-quinone)Mn(CO)3](-) upon further deprotonation of [(?(5)-semiquinone)Mn(CO)3] at the NP surface. We have demonstrated chemistry at the intersection of surface-modified NPs and coordination polymers through the growth of organometallic coordination polymers onto the surface modified Fe3O4 NPs. The resulting magnetic NP/organometallic coordination polymer hybrid material exhibited both the unique superparamagnetic behavior associated with Fe3O4 NPs and the paramagnetism attributable to the metal nodes, depending upon the magnetic range examined. By the use of functionalized [(?(5)-semiquinone)Mn(CO)3] complexes, we attained the formation of an organometallic monolayer on the surface of highly ordered pyrolitic graphite (HOPG). The resulting organometallic monolayer was not simply a random array of manganese atoms on the surface, but rather consisted of an alternating "up and down" spatial arrangement of Mn atoms extending from the HOPG surface due to hydrogen bonding of the quinonoid complexes. We also showed that the topology of metal atoms on the surface could be controlled through the use of quinonoid metal complexes. A quinonoid rhodium complex showed catalytic activity in Suzuki-Miyaura type reaction. As a result of the excellent stability of the homogeneous catalyst [(quinone)Rh(COD)](-) in water, we also successfully demonstrated catalyst recycling in 1,2- and 1,4-addition reactions. The compound [(quinone)Ir(COD)](-) showed significantly poorer catalytic activity in 1,4-addition reactions. Following upon the excellent coordination ability of the quinonoid rhodium complexes to metal centers, we synthesized organometallic coordination polymer nanocatalysts and silica gel-supported quinonoid rhodium catalysts, the latter using a surface sol-gel technique. The resulting heterogeneous catalysts showed activity in the stereospecific polymerization of phenylacetylene. PMID:23745596

Kim, Sang Bok; Pike, Robert D; Sweigart, Dwight A

2013-06-01

163

Novel lanthanidetransition-metal coordination polymer materials: Crystal engineering challenges and a ligand-directed assembly strategy  

Microsoft Academic Search

The challenge on lanthanidetransition-metal (LnM) coordination polymer crystals and a corresponding ligand-directed assembly strategy of crystal engineering were studied. The multifunctional isonicotinate with mixed donor sites was selected as the directing ligand to link lanthanide and transition-metal ions on the basis of the coordination nature of both different types of metal ions. A new three-dimensional (3D) LnM heterometallic coordination polymer

Wanyan Xiao; Xiaojun Gu; Dongfeng Xue

2009-01-01

164

Nature of one-dimensional excitons in polysilanes  

NASA Astrophysics Data System (ADS)

One-dimensional (1D) exciton states have been studied by nonlinear optical spectroscopy on organosilicon polymer polysilanes (PS's). From systematic variation of the linear and nonlinear optical spectra upon changing the backbone conformation, the following two characteristic exciton parameters have been evaluated; the ratio \\|?(3)\\|/? of the modulus of third-order nonlinear optical susceptibility \\|?(3)\\| to the absorption coefficient ? and the energy difference ?E12 between the lowest and second lowest exciton energies E1 and E2, which are theoretically related, respectively, to the Bohr radius and to the binding energy of excitons. It was found that \\|?(3)\\|/? increases, whereas ?E12 remains almost unchanged, with increasing valence and conduction-band widths. These features cannot be accounted for either by the Wannier- or Frenkel-type exciton model. From analysis by a unified 1D exciton model, it has been concluded that the 1D excitons in PS's represent a unique system having an intermediate character in between the Frenkel- and Wannier-exciton regimes, where the on-site Coulomb (or exchange) interactions play a crucial role in determining the characteristic exciton structures as observed.

Hasegawa, T.; Iwasa, Y.; Koda, T.; Kishida, H.; Tokura, Y.; Wada, S.; Tashiro, H.; Tachibana, H.; Matsumoto, M.

1996-10-01

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

Synthesis, crystal structures and luminescent properties of two 4d-4f Ln-Ag heterometallic coordination polymers based on anion template  

SciTech Connect

Two new 4d-4f Ln-Ag heterometallic coordination polymers, {l_brace}[Ln{sub 3}Ag{sub 5}(IN){sub 10}(H{sub 2}O){sub 7}].4(ClO{sub 4}).4(H{sub 2}O){r_brace}{sub n} (Ln=Eu (1) and Sm (2), HIN=isonicotinic acid), have been synthesized under hydrothermal conditions by reactions of Ln{sub 2}O{sub 3}, AgNO{sub 3}, HIN and HClO{sub 4}, and characterized by elemental analysis, IR, thermal analysis and single-crystal X-ray diffraction. It is proved that HClO{sub 4} not only adjusts the pH value of the reaction mixture, but also acts as anion template. The structure determination reveals that 1 and 2 are isostructural and feature a novel two-dimensional (2D) layered hetrometallic structure constructed from one-dimensional Ln-carboxylate chains and pillared Ag(IN){sub 2} units. The 2D layers are further interlinked through Ag...Ag and Ag...O(ClO{sub 4}{sup -}) multiple weak interactions, which form a rare Ag-ClO{sub 4} ribbon in lanthanide-transition metal coordination polymers, to give rise to a three-dimensional supramolecular architecture. Moreover, the luminescent properties of these two compounds have also been investigated at room temperature. -- Graphical abstract: Two new anion-templated 2D 4d-4f Ln-Ag heterometallic coordination polymers based on novel lanthanide-carboxylate chains and pillared Ag(IN){sub 2} units, {l_brace}[Ln{sub 3}Ag{sub 5}(IN){sub 10}(H{sub 2}O){sub 7}].4(ClO{sub 4}).4(H{sub 2}O){r_brace}{sub n} (Ln=Eu (1) and Sm (2), HIN=isonicotinic acid), have been hydrothermally synthesized and structurally characterized. 1 and 2 exhibit good luminescent properties. Display Omitted Research highlights: > Two 2D Eu (Sm)-Ag coordination polymers templated by perchlorate anion have been synthesized. > Polymers consist of novel 1D lanthanide-carboxylate chains. > In both structures, there are rare Ag...Ag and Ag...O(ClO{sub 4}{sup -}) multiple weak interactions. > Both compounds exhibit good luminescent properties.

Fan, Le-Qing, E-mail: lqfan@hqu.edu.c [Institute of Materials Physical Chemistry, and the Key Laboratory for Functional Materials of Fujian Higher Education, Huaqiao University, Quanzhou, Fujian 362021 (China); Chen, Yuan [Institute of Materials Physical Chemistry, and the Key Laboratory for Functional Materials of Fujian Higher Education, Huaqiao University, Quanzhou, Fujian 362021 (China); Wu, Ji-Huai, E-mail: jhwu@hqu.edu.c [Institute of Materials Physical Chemistry, and the Key Laboratory for Functional Materials of Fujian Higher Education, Huaqiao University, Quanzhou, Fujian 362021 (China); Huang, Yun-Fang [Institute of Materials Physical Chemistry, and the Key Laboratory for Functional Materials of Fujian Higher Education, Huaqiao University, Quanzhou, Fujian 362021 (China)

2011-04-15

167

A novel coordination polymer with dicyanamide ligand: multi-dimensional architecture stabilized by hydrogen bonding  

Microsoft Academic Search

A novel dicyanamide (dca) complex, [Cu(pn)(dca)2]n (pn=1,2-diaminopropane), was synthesized and characterized. X-ray diffraction analysis reveals that the title complex crystallizes in the monoclinic space group C2\\/c with a=12.436(5)A?,b=8.395(3)A?,c=20.747(8)A?,?=96.662(6), Z=8, and R1=0.0476, wR2=0.1094. The complex exhibits one-dimensional zigzag chain structure constructed by ?1,5-dca bridges. The coordination geometry around the copper atom was a distorted square-pyramid. The spectroscopic and magnetic properties have

Xiao-Yan Chen; Peng Cheng; Bin Zhao; Shi-Ping Yan; Dai-Zheng Liao; Zong-Hui Jiang

2003-01-01

168

Coordination steric effect of N, N-dimethylformamide, N, N-dimethylacetamide and N-methyl-2-pyrrolidone on the assembly of coordination polymers  

Microsoft Academic Search

Three coordination polymers 1, 2 and 3 have been synthesized in DMF (N,N-dimethylformamide), DMA (N,N-dimethylacetamide) and NMP (N-methyl-2-pyrrolidone), respectively. In 1, DMF solvent molecule coordinates to zinc ion as an ancillary ligand, and 1D chain structure is obtained. 2 and 3 are isostructural, in which solvent molecules, DMA and NMP, do not coordinate to zinc ions, and 1D double stranded

Hui-Min Li; Shi-Yao Yang; Jian-Wei Wang; La-Sheng Long; Rong-Bing Huang; Lan-Sun Zheng

2010-01-01

169

SUSY-hierarchy of one-dimensional reflectionless potentials  

SciTech Connect

A class of one-dimensional reflectionless potentials is studied. It is found that all possible types of the reflectionless potentials can be combined into one SUSY-hierarchy with a constant potential. An approach for determination of a general form of the reflectionless potential on the basis of construction of such a hierarchy by the recurrent method is proposed. A general integral form of interdependence between superpotentials with neighboring numbers of this hierarchy, opening a possibility to find new reflectionless potentials, is found and has a simple analytical view. It is supposed that any possible type of the reflectionless potential can be expressed through finite number of elementary functions (unlike some presentations of the reflectionless potentials, which are constructed on the basis of soliton solutions or are shape invariant in one or many steps with involving scaling of parameters, and are expressed through series). An analysis of absolute transparency existence for the potential which has the inverse power dependence on space coordinate (and here tunneling is possible), i.e., which has the form V (x) = {+-} {alpha}/ vertical bar x-x{sub 0} vertical bar{sup n} (where {alpha} and x{sub 0} are constants, n is natural number), is fulfilled. It is shown that such a potential can be reflectionless at n = 2 only. A SUSY-hierarchy of the inverse power reflectionless potentials is constructed. Isospectral expansions of this hierarchy are analyzed.

Maydanyuk, Sergei P. [Institute for Nuclear Research, National Academy of Sciences of Ukraine prosp. Nauki, 47, Kiev-28, 03680 (Ukraine)]. E-mail: maidan@kinr.kiev.ua

2005-04-01

170

Chelating Schiff base assisted azide-bridged Mn(II), Ni(II) and Cu(II) magnetic coordination polymers.  

PubMed

Four new Mn(II), Ni(II) and Cu(II) coordination polymers [Mn2(L1)(?(1,1)-N3)2(?(1,3)-N3)2]n (1), [Ni(L2)2(?(1,3)-N3)]n(ClO4)n (2), [Cu(L3)(?(1,1)-N3)(N3)]n (3) and [Cu(L4)(?(1,1)-N3)2]n (4) (L1 = N,N?-bis(2-pyridylmethylene)ethane-1,2-diamine, L2 = N-(2-pyridylmethylene)methylamine, L3 = N-(2-pyridylmethylene)-3-pyridylamine, L4 = N-(2-pyridylmethylene)-tbutylamine) have been synthesized and characterized by single-crystal X-ray analysis and magnetic measurements. Complex 1 indicates a stoichiometry-dependent structural change (based on Mn:L1:N3 = 2:1:4 molar ratio) and consists of two-dimensional (2-D) (4,4) net layers, in which Mn(II) centers are co-bridged by single end-to-end (EE), double end-on (EO) azide and chelate-bridging L1 ligands. Complex 2 shows a single EE azide-bridged one-dimensional (1-D) Ni(II) chain. Complexes 3 and 4 indicate single EO and double EO azide-bridged 1-D Cu(II) chains, respectively. Complex 1 exhibits weak ferromagnetism due to its intra-layer spin-canting with T(c) = 20 K. Complex 2 shows an unusual intra-chain ferromagnetic coupling and spin-canting behaviour. Both complexes 3 and 4 exhibit intra-chain antiferromagnetic interactions. Magneto-structural parameters for these related complexes were also discussed. PMID:23007857

Bai, Shi-Qiang; Fang, Chen-Jie; He, Zheng; Gao, En-Qing; Yan, Chun-Hua; Hor, T S Andy

2012-11-21

171

Hydrogen-bond-directing effect in the ionothermal synthesis of metal coordination polymers.  

PubMed

Four new cobalt coordination polymers, (EMIm)[Co2(TMA-H)2(44bpy)3]Br 1, (EMIm)[Co(TMA-H)(44bpy)2](44bpy)Br 2, (EMIm)[Co(TMA)(Im-H)]3 and (EMIm)2[Co(TMA)2(TED-H2)] 4, were prepared from 1-ethyl-3-methyl imidazolium bromide (EMIm-Br). All the compounds have similar two-dimensional cobalt trimesate (TMA) coordination layers but different three-dimensional supramolecular architectures that contain one of three potentially ditopic amines, 4,4'-bipyridine (44bpy), imidazole (Im-H) and triethylenediamine (TED). Two-fold interpenetration of hydrogen-bonding networks was found for 1, 2 and 4. The coordination layers of 1 and 2 are neutral while 3 and 4 have anionic molecular assemblies. The use of organic amines, that act as supramolecular bridging ligands, introduces hydrogen-bond-directing effects in the ionothermal synthesis of metal coordination polymers. Hydrogen bonding helps to align the packing between the coordination layers and control the formation of 3D supramolecular networks. In 1, hydrogen bonds between the ionic species within the channels direct the alignment of non-directional electrostatic interactions between EMIm+ and Br(-) ions, which is a rare case of a hydrogen-bond-templating effect of ionic liquids in ionothermal synthesis. PMID:18648702

Lin, Zhuojia; Li, Yang; Slawin, Alexandra M Z; Morris, Russell E

2008-06-06

172

A new microporous structure constructed by a lanthanide-carboxylate coordination polymer  

Microsoft Academic Search

A novel microporous structure constructed by a lanthanide-carboxylate coordination polymer of [Nd(C8H5NO4)1.5(H2O)2]2H2O is reported. Nd3+ ion is in the distorted square anti-prism coordination environment. Both carboxyl groups of each ligand link Nd3+ ions in the same fashion to engender the open-framework structure along Y-axis. Pendant groups in microporous structure join guest water molecules via hydrogen bond.

Hai Tao Xu; Neng Wu Zheng; Xiang Lin Jin; Ru Yi Yang; Zheng Quan Li

2003-01-01

173

Ligand-directed metal(II) coordination polymers: Unusual disorder, and photoluminescence  

Microsoft Academic Search

2,6-Dimethyl-4-phenylpyridine-3,5-dicarboxylic acid (H2mppdc, H2L) is firstly employed in coordination chemistry. Two metal-organic coordination polymers with a general formula of M2L2(4,4?-bpy)x(H2O)4?2x (M=Zn or Co, x=1 or 2) are assembled from H2L, 4,4?-bipyridine, zinc and cobalt salt under hydrothermal conditions, and characterized by single-crystal X-ray diffraction analyses. Of the crystal structures of title compounds, L ligands, limited in the environment from 4,4?-bipyridine,

Kun-Lin Huang

2008-01-01

174

Periodicity versus Chaos in One-Dimensional Dynamics  

Microsoft Academic Search

We survey recent results in one-dimensional dynamics and, as an application, we derive rigorous basic dynamical facts for two standard models in population dynamics, the Ricker and the Hassell families. We also informally discuss the concept of chaos in the context of one-dimensional discrete time models. First we use the model case of the quadratic family for an informal exposition.

Hans Thunberg

2001-01-01

175

End-to-end Dicyanamido-bridged Heteronuclear Cu(II)\\/Na(I) Coordination Polymers: Synthesis, Electrochemical, and Magnetic Properties  

Microsoft Academic Search

A dicyanamido-bridged polymeric complex formulated as [NaCu2(dca)2(salpn)2]n (1) (dca = dicyanamide anion, H2salpn = N, N-bis (salicylaldehyde)propylenediimine Schiff base) has been synthesized and characterized systematically. The complex 1 forms the single end-to-end (-) dicyanamido-bridged one dimensional (1D) infinite chain, and the sodium cations ligated by the dca ion ligands display a 1D zigzag chain array, where the diverse coordination fashions

Xun Feng; Xin-Ge Shi; Li-Ya Wang; Cheng Zhi Xie; Qian-Qian Sun; Peng-Peng Lei

2010-01-01

176

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

Microsoft Academic Search

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 (PPh4)3Cu4(dca)11 salt crystallizes in the monoclinic

John A. Schlueter; Jamie L. Manson; Urs Geiser

2007-01-01

177

1D sodium ditetrazole coordination polymer obtained through in situ hydrothermal ligand synthesis  

Microsoft Academic Search

Hydrothermal treatment of ZnCl2, 1,4-dicyanoethylene, NaN3, and water in the presence of NaOH at ca. 130 C unexpectedly but welcomingly offers colorless crystals of the compound 1. To the best of our knowledge, 1 is the first ditetrazole coordination polymer containing sodium synthesized through in situ hydrothermal 2+3 cycloaddition reaction between cyano and azide groups.

Xue-Feng Huang; Yu-Mei Song; Qian Wu; Qiong Ye; Xiong-Bin Chen; Ren-Gen Xiong; Xiao-Zeng You

2005-01-01

178

Novel Zn(II) ladder-like coordination polymer constructed from designed ferrocenyl ligand  

Microsoft Academic Search

Reaction of Zn(NO3)26H2O with 3-(4-carboxylphenylamino)-1-ferrocenyl-2-butylen-1-one (HL) and 4,4?-bipyridine (4,4?-bipy) in methanol solution resulted in a novel ladder-like coordination polymer {[Zn2L2(?2-L)2(4,4?-bipy)2]MeOH}n (1). Its crystal structure, thermal and electrochemical properties are presented.

Hai Fang Zhang; Zi Feng Li; Gang Li; Li Peng Wang; Jia Bin Li; Guang Jian Mei

2008-01-01

179

Low-dimensional porous coordination polymers based on 1,2-bis(4-pyridyl)hydrazine: from structure diversity to ultrahigh CO2/CH4 selectivity.  

PubMed

Solvothermal reactions of metal salts, benzenedicarboxylic acids, and 4,4'-azopyridine (azpy) in different conditions produced four coordination polymers, namely, [Zn(3)(bdc)(3)(bphy)(3)]2DMF10H(2)O (3; H(2)bdc = 1,4-benzenedicarboxylic acid, bphy = 1,2-bis(4-pyridyl)hydrazine, and DMF = N,N-dimethylformamide), [Ni(bdc)(bphy)]DMF3.5H(2)O (4), [Zn(nipa)(bphy)]EtOH (5; H(2)nipa = 5-nitroisophthalic acid), and [CoBr(bdc)(0.5)(bphy)]2DMAH(2)O (6; DMA = N,N-dimethylacetamide), in which the azpy ligand was in situ reduced. Structural determination reveals that 3-5 consist of the same metal/ligand ratio and similar coordination modes, as well as similar two-dimensional square-grid networks, but differ from their packing/interpenetration modes. 3 consists of alternately arranged single layers and interweaved double layers. Single layers in 4 directly stack in an offset fashion, while 5 is constructed of interdigitated double layers. 6 is a one-dimensional ladderlike structure, which could be regarded as that half of the bridging benzenedicarboxylate ligands in 3-5 are replaced by monodentate bromide ions. Interestingly, the crystal structures of these low-dimensional coordination polymers contain considerable solvent-accessible voids. Thermogravimetric curves, powder X-ray diffraction, and gas sorption experiments were used to study the potential porosity of these structures, which indicated that they can all reversibly desorb and adsorb solvent molecules. In particular, 4 showed gated sorption behavior and high CO(2)/CH(4) selectivity because of its flexible structure. PMID:22564113

Liu, Xiao-Min; Lin, Rui-Biao; Zhang, Jie-Peng; Chen, Xiao-Ming

2012-05-07

180

Hardening transition in a one-dimensional model for ferrogels.  

PubMed

We introduce and investigate a coarse-grained model for quasi one-dimensional ferrogels. In our description the magnetic particles are represented by hard spheres with a magnetic dipole moment in their centers. Harmonic springs connecting these spheres mimic the presence of a cross-linked polymer matrix. A special emphasis is put on the coupling of the dipolar orientations to the elastic deformations of the matrix, where a memory effect of the orientations is included. Although the particles are displaced along one spatial direction only, the system already shows rich behavior: as a function of the magnetic dipole moment, we find a phase transition between "soft-elastic" states with finite interparticle separation and finite compressive elastic modulus on the one hand, and "hardened" states with touching particles and therefore diverging compressive elastic modulus on the other hand. Corresponding phase diagrams are derived neglecting thermal fluctuations of the magnetic particles. In addition, we consider a situation in which a spatially homogeneous magnetization is initially imprinted into the material. Depending on the strength of the magneto-mechanical coupling between the dipole orientations and the elastic deformations, the system then relaxes to a uniaxially ferromagnetic, an antiferromagnetic, or a spiral state of magnetization to minimize its energy. One purpose of our work is to provide a largely analytically solvable approach that can provide a benchmark to test future descriptions of higher complexity. From an applied point of view, our results could be exploited, for example, for the construction of novel damping devices of tunable shock absorbance. PMID:23742515

Annunziata, Mario Alberto; Menzel, Andreas M; Lwen, Hartmut

2013-05-28

181

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

182

Distributed feedback lasing from a composite poly(phenylene vinylene)-nanoparticle one-dimensional photonic crystal.  

PubMed

Nanoparticle one-dimensional photonic crystals exhibit intense, broadband reflectivity coupled with a unique mesoporosity. The latter property allows for infiltration of the one-dimensional photonic crystal with functional materials, such as emitting polymers, which in turn can lead to the fabrication of composites whereby the emitter's emission can be modulated by the photon density of states of the photonic crystal. We exploit this interaction in order to produce efficient distributed feedback lasing from a composite poly(phenylene vinylene)-infiltrated nanoparticle one-dimensional photonic crystal. PMID:19842702

Puzzo, Daniel P; Scotognella, Francesco; Zavelani-Rossi, Margherita; Sebastian, Maria; Lough, Alan J; Manners, Ian; Lanzani, Guglielmo; Tubino, Riccardo; Ozin, Geoffrey A

2009-12-01

183

One-dimensional Nel walls under applied external fields  

NASA Astrophysics Data System (ADS)

We present a detailed analysis of one-dimensional Nel walls in thin uniaxial ferromagnetic films in the presence of an in-plane applied external field in the direction normal to the easy axis. Within the reduced one-dimensional thin film model, we formulate a non-local variational problem whose minimizers are given by one-dimensional Nel wall profiles. We prove existence, uniqueness (up to translations and reflections), regularity, strict monotonicity and the precise asymptotics of the decay of the minimizers in the considered variational problem.

Chermisi, Milena; Muratov, Cyrill B.

2013-11-01

184

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

185

Electron Transport in Some One-Dimensional Metal Complex Semiconductors.  

National Technical Information Service (NTIS)

The subject of one dimensional electronic interactions in transition metal complexes has been treated in several other papers in this volume, with particular emphasis on systems which exhibit 'metallic' properties. The main purpose of this paper is to dev...

L. V. Interrante

1975-01-01

186

Global Existence and Asymptotics in One-Dimensional Nonlinear Viscoelasticity.  

National Technical Information Service (NTIS)

In this paper we survey recent results concerning global existence and decay of smooth solutions of certain quasilinear hyperbolic Volterra equations which provide models for the motion of one-dimensional viscoelastic solid of the Boltzmann type. We also ...

W. J. Hrusa J. A. Nohel

1983-01-01

187

A Controlled Experiment with One-Dimensional Interpolation.  

National Technical Information Service (NTIS)

The performances of various one-dimensional interpolation schemes are evaluated using mean square errors of the point-wise estimates of the function values and component-wise estimates of the power spectrum. The schemes of interpolation considered include...

C. H. Yang

1974-01-01

188

One-dimensional random lasing in a single organic nanofiber.  

PubMed

One-dimensional light amplification in individual p-sexiphenyl nanofibers is investigated. The influence of fiber morphology on light propagation properties is studied via optical and atomic force microscopy. Isolated nanofibers are shown to yield low-threshold random laser emission in the deep blue. Model calculations of coherent light propagation in one-dimensional random media qualitatively reproduce the experimental results. Implications for photonic nanosensors are briefly discussed. PMID:16853817

Quochi, Francesco; Cordella, Fabrizio; Mura, Andrea; Bongiovanni, Giovanni; Balzer, Frank; Rubahn, Horst-Gnter

2005-11-24

189

Directed Assembly of One-Dimensional Nanostructures into Functional Networks  

Microsoft Academic Search

One-dimensional nanostructures, such as nanowires and nanotubes, represent the smallest dimension for efficient transport of electrons and excitons and thus are ideal building blocks for hierarchical assembly of functional nanoscale electronic and photonic structures. We report an approach for the hierarchical assembly of one-dimensional nanostructures into well-defined functional networks. We show that nanowires can be assembled into parallel arrays with

Yu Huang; Xiangfeng Duan; Qingqiao Wei; Charles M. Lieber

2001-01-01

190

Dynamical studies of a one-dimensional quasy-crystal  

Microsoft Academic Search

The dynamical properties of a one-dimensional quasicrystal with the structure of a complex Penrose chain, which consists of two different interpenetrating Penrose chains, are investigated. The one-dimensional quasicrystals are found to have a self-similar sequence distribution of states in its vibration spectrum, and both extended states and weakly localized states among its vibration modes. A comparison of the present study

Lei Chen; Gen-You Hu; Rui-Bao Tao

1986-01-01

191

Preparation and characterization of lanthanide-azo-dye coordination polymers and polymer thin films via layer-by-layer depositions.  

PubMed

A series of tartrazine-lanthanide dye compounds has been synthesized and characterized. Structural studies reveal that the light rare-earth elements La, Ce, Pr and Nd form coordination compounds with tartrazine ligands in a 1:1 ratio and result in 1-D 'fish-bone' chain-like structures having uncoordinated organosulfonate groups on each side of the chain. However, reactions of tartrazine and heavy rare-earth elements Ho, Er, Tm and Yb, in the presence of auxiliary 1,10-phenanthroline, give new 1-D coordination polymers in which uncoordinated organosulfonate groups are located on the same side of the chains. The tartrazine ligands display similar but slightly different coordination modes in both types of structures and the 1,10-phenanthroline plays a vital role in the formation of heavy rare-earth dye compounds. Based on the knowledge of their structures, the light rare-earth dye compounds were utilized to assemble with positively-charged PEI into multilayer thin films by means of layer-by-layer depositions. The as-synthesized thin films showed enhanced stability and consistency on solid surfaces. PMID:20944840

Han, Li-Wei; L, Jian; Liu, Tian-Fu; Gao, Shui-Ying; Cao, Rong

2010-10-13

192

A facile route for preparing a mesoporous palladium coordination polymer as a recyclable heterogeneous catalyst.  

PubMed

To overcome the separation difficulty of the palladium-based homogeneous catalyst, the palladium complex can be anchored on various supports such as silica, polymers and nanoparticles. For the same purpose, we describe a general and facile method to immobilize palladium bis(phosphine) complexes on the basis of the technique widely used for metal-organic framework (MOF) synthesis, yielding a mesoporous coordination polymer palladium-CP1. Although palladium complexes are generally not stable enough to allow further manipulation, we succeeded in preparation of a palladium coordination polymer without by-product Pd clusters or nanoparticles. The fresh palladium-CP1 catalyst exhibits a yield close to 55% for tolane at room temperature and 24 h in Sonogashira coupling of iodobenzene and phenylacetylene, as compared with a yield of 89% for its homogeneous counterpart [Pd(PPh(3))(2)Cl(2)]. Furthermore, this catalyst is stable enough to be reused more than four times with no Pd and Zn leaching. Therefore this new immobilization method offers great promise for the produce of recyclable palladium heterogeneous catalysts with higher activity and higher thermal and chemical stability in the future. PMID:22382505

Zhang, Siyong; Liu, Qinghua; Shen, Ming; Hu, Bingwen; Chen, Qun; Li, Hexing; Amoureux, Jean-Paul

2012-03-01

193

Lanthanide coordination polymer nanoparticles for sensing of mercury(II) by photoinduced electron transfer.  

PubMed

The metal-organic coordination polymers at the nanoscale have emerged as attractive nanomaterials due to their tunable nature. In this work, we for the first time prepared an adenine-based lanthanide coordination polymer nanoparticle (CPNP) with fluorescence sensing function. This kind of CPNP was composed of adenine, terbium ion (Tb(3+)), and dipicolinic acid (DPA) as an auxiliary linking molecule that can sensitize the fluorescence of Tb(3+). The fluorescence of the CPNPs is very weak due to the existence of photoinduced electron transfer (PET) from adenine to DPA, which prevents the intramolecular energy transfer from DPA to Tb(3+), leading to the quench of fluorescence of the CPNPs. In the presence of Hg(2+), however, significant enhancement in the fluorescence of CPNPs was observed because of the suppression of the PET process by the coordination of Hg(2+) with adenine. As a kind of Hg(2+) nanosensor, the CPNPs exhibit excellent selectivity and ultrahigh sensitivity up to the 0.2 nM detection limit. The CPNPs also possess an approximately millisecond-scale-long fluorescence lifetime due to the inclusion of Tb(3+) ions. We envision that the CPNPs could find great potential applications in ultrasensitive time-resolved fluorometric assays and biomedical imaging in the future owing to their long emission lifetimes, excellent dispersion, and stability in aqueous solution. PMID:23121519

Tan, Hongliang; Liu, Baoxia; Chen, Yang

2012-11-09

194

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

195

Control of Crystal Structure and Magnetism in Copper(II) Fluoride Based Coordination Polymers  

NASA Astrophysics Data System (ADS)

Whereas magnetic copper (II) halide (halide = chloride or bromide) coordination polymers have been frequently studied, the copper(II) fluoride analogs have been much less investigated. This is due in part to synthetic challenges associated with solubility and reactivity. In analogy to cuprates, Cu-F-Cu linkages are expected to provide strong magnetic superexchange. The magnetic structure of such systems can be tuned by choice of ancillary ligand. Herein, we describe the use of various pyridines, diazines, and triazoles that have the ability to define the structural and magnetic dimensionality. Hydrogen bonding to the fluoride ligand provides an additional opportunity for designing molecule-based materials through a `crystal-engineering' approach. Competition for intermolecular interactions frequently enables stimuli responsive behavior, including pressure-induced phase transitions. This will be illustrated for the CuF2(H2O)2(pyrazine) coordination polymer and the five-coordinate CuF2(H2O)2(3-chloropyridine) molecular solid. The use of new synthetic methods, including the use of high pressure, will be described. Subtle changes in reaction conditions leads to significant changes in structural and magnetic properties.

Schlueter, John; Lapidus, Saul; Manson, Jamie

2013-03-01

196

Coordination  

NSDL National Science Digital Library

Coordination is an organized working together of muscles and groups of muscles aimed at bringing about a purposeful movement such as walking or standing. Coordination involves timing and concentration.

Olivia Worland (Purdue University;Biological Sciences)

2008-06-06

197

ONE-DIMENSIONAL MARGINALS OF OPERATOR STABLE LAWS AND THEIR DOMAINS OF ATTRACTION  

Microsoft Academic Search

Operator stable laws are the weak limits of ane normalized partial sums of i.i.d. random vectors. It is known that the one-dimensional marginals of operator stable laws need not be stable, or even attracted to a stable law. In this paper we show that for any operator stable law, there exists a basis in which the marginals along every coordinate

Mark M. Meerschaert; Hans-Peter Scheer

1998-01-01

198

Synthesis, structures, and magnetic properties of metal-coordination polymers with benzenepentacarboxylate linkers.  

PubMed

Three hybrid organic-inorganic coordination polymers with benzenepentacarboxylate (BPCA) linkers, [Co3(C6H(COO)5)(OH)(H2O)3] (1-Co), [Zn3(C6H(COO)5)(OH)(H2O)3] (2-Zn), and [Co5(C6H(COO)5)2(H2O)12].(H2O)12 (3-Co), were synthesized hydrothermally and were characterized structurally and magnetically. 1-Co and 2-Zn are isostructural [C2/c; Z=8; 1-Co, a=19.5350(6) A, b=10.4494(4) A, and c=13.2353(5) A, beta=97.2768(8) degrees; 2-Zn, a=19.5418(9) A, b=10.3220(10) A, and c=13.4660(10) A, beta=98.455(10) degrees] with three-dimensional structures that contain [M6] secondary building units bridged by BPCA ligands. A different cobalt-based compound, 3-Co, forms at lower pH and lower reaction temperature. Its structure [P21/c; Z=2; a=12.6162(2) A, b=11.3768(2) A, and c=15.3401(3) A, beta=91.539(1) degrees] is a more loosely packed framework with free (noncoordinated) carboxylic groups pointing at water-filled cavities in the framework. The magnetic phase diagram of 1-Co established through detailed magnetic measurements shows a metamagnetic transition below TN=3.8 K. The less-packed compound 3-Co, on the other hand, remains paramagnetic above 1.9 K. The three compounds are the first examples of coordination polymers with benzenepentacarboxylate linkers and fill the gap of coordination polymers involving benzenepolycarboxylate linkers of the general type C6H6-n(COOH)n, where n=2-6. PMID:18095675

Wang, Xin-Yi; Sevov, Slavi C

2007-12-21

199

Spontaneous resolution of a mixed-ligand nickel(II) coordination polymer with achiral precursors.  

PubMed

Metal-center-driven spontaneous resolution of a chiral coordination polymer, [Ni(SDB)(BIX)](n) (1), from achiral precursors has been probed by single-crystal X-ray diffraction and circular dichroism spectroscopy. Enantiomorphs 1P and 1M showed a parallel interpenetrated 2D ? 3D chiral framework with (8(2).10) topology. Switching of the metal center under the same reaction parameters resulted in isostructural achiral and noninterpenetrating (4,4) grid-type sql networks [M(SDB)(BIX)](n), where M = Co(II), Zn(II), and Cd(II) for 2-4, respectively. PMID:22937770

Bisht, Kamal Kumar; Suresh, Eringathodi

2012-08-31

200

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

201

Syntheses, crystal structures and magnetic properties of three copper(II) coordination polymers with the flexible ligand 1,2-bis(1,2,4-triazol-1-yl)ethane or 1,2-bis(imidazol-1-yl)ethane  

NASA Astrophysics Data System (ADS)

In order to investigate the influence of the flexibility of the ligand molecules and the coordination counter anions on the architecture of coordination polymers, three new copper(II) coordination polymers [Cu(bte)2(dca)2]n (1), [Cu(bte)(NCS)2]n (2) and [Cu(bim)(NCS)2]n (3) were synthesized using the flexible five-membered heterocyclic ligands 1,2-bis(1,2,4-triazol-1-yl)ethane (bte), 1,2-bis(imidazol-1-yl)ethane (bim) and the anion ligands dicyanamide (dca) and thiocyanate. They are characterized by elemental analysis, IR, thermogravimetric analysis and X-ray diffraction analysis. The X-ray diffraction analysis shows that complexes 1, 2 and 3 form the one-dimensional double-stranded chain, linear chain and zigzag chain structures, respectively. The magnetic properties for complexes 1, 2 and 3 have also been studied.

Ding, Jiangang; Ge, Haiyan; Zhang, Yumei; Li, Baolong; Zhang, Yong

2006-01-01

202

Coronates, spherical containers, bowl-shaped surfaces, porous 1D-, 2D-, 3D-metallo-coordination polymers, and metallodendrimers.  

PubMed

Supramolecular coordination cages and polymers bear exceptional advantages over their organic counterparts. They are available in one-pot reactions and in high yields and display physical properties that are generally inaccessible with organic species. Moreover, their weak, reversible, noncovalent bonding interactions facilitate error checking and self-correction. This review emphasizes the achievements in supramolecular coordination container as well as polymer chemistry initiated by serendipity and their materialization based on rational design. The recognition of similarities in the synthesis of different supramolecular assemblies allows prediction of potential structures in related cases. The combination of detailed symmetry considerations with the basic rules of coordination chemistry has only recently allowed for the design of rational strategies for the construction of a variety of nanosized spherical containers, bowls, 1D-, 2D-, and 3D-coordination polymers with specified size and shape. PMID:22160460

Saalfrank, Rolf W; Scheurer, Andreas

2012-01-01

203

pH-dependent assembly of 0D to 3D Keggin-based coordination polymers: structures and catalytic properties.  

PubMed

Four Keggin-based coordination polymers, namely, {[Cu2(4,4'-bpy)(4,4'-Hbpy)4(H2O)4](SiW12O40)2(H2O)4}n (1), {[Cu2(4,4'-bpy)(4,4'-Hbpy)6(SiW12O40)3](4,4'-Hbpy)2(H2O)7}n (2), {[Cu2(mu2-H2O)2(4,4'-bpy)3(SiW12O40)](H2O)6}n (3) and {[Cu2(mu2-OH)(4,4'-bpy)3(SiW12O40)(H2O)] [Cu2(mu2-O)(4,4'-bpy)4(H2O)2]0.5 x (H2O)3}n (4) (4,4'-bpy = 4,4'-bipyridine) were prepared through the hydrothermal reaction of silicotungstic acid, copper(II) nitrate and 4,4'-bipyridine under different pH conditions. Coordination polymers 1 and 2, which exhibit 0D and 1D structures respectively, were prepared at pH = 3.5. At pH = 5.5, a 2D coordination polymer 3 was obtained. Increasing the pH of the reaction to 8.5 led to a 3D coordination polymer 4. The structural diversities of 1-4 reveal that the pH value of the reaction plays a key role in the assembly of POM-based coordination polymers. Investigation of the catalytic properties of 1-4 for the oxidation of ethylbenzene indicates that the catalytic activity of the coordination polymers is closely related to the protonated extent of 4,4'-bpy in the coordination polymers. PMID:19859606

Yu, Fan; Kong, Xiang-Jian; Zheng, Yun-Yun; Ren, Yan-Ping; Long, La-Sheng; Huang, Rong-Bin; Zheng, Lan-Sun

2009-09-18

204

Faraday patterns in coupled one-dimensional dipolar condensates  

NASA Astrophysics Data System (ADS)

We study Faraday patterns in quasi-one-dimensional dipolar Bose-Einstein condensates with parametrically driven dipolar interactions. We show that in the presence of a roton minimum in the excitation spectrum, the emergent Faraday waves differ substantially in two- and one-dimensional geometries, providing a clear example of the key role of confinement dimensionality in dipolar gases. Moreover, Faraday patterns constitute an excellent tool to study nonlocal effects in polar gases, as we illustrate with two parallel quasi-one-dimensional dipolar condensates. Nonlocal interactions between the condensates give rise to an excitation spectrum characterized by symmetric and antisymmetric modes, even in the absence of hopping. We show that this feature, absent in nondipolar gases, results in a critical driving frequency at which a marked transition occurs between correlated and anticorrelated Faraday patterns in the two condensates. Interestingly, at this critical frequency, the emergent Faraday pattern stems from a spontaneous symmetry-breaking mechanism.

?akomy, Kazimierz; Nath, Rejish; Santos, Luis

2012-08-01

205

Integration of intrinsic proton conduction and guest-accessible nanospace into a coordination polymer.  

PubMed

We report the synthesis and characterization of a coordination polymer that exhibits both intrinsic proton conductivity and gas adsorption. The coordination polymer, consisting of zinc ions, benzimidazole, and orthophosphate, exhibits a degree of flexibility in that it adopts different structures before and after dehydration. The dehydrated form shows higher intrinsic proton conductivity than the original form, reaching as high as 1.3 10(-3) S cm(-1) at 120 C. We found that the rearranged conduction path and liquid-like behavior of benzimidazole molecules in the channel of the framework afforded the high proton conductivity. Of the two forms of the framework, only the dehydrated form is porous to methanol and demonstrates guest-accessible space in the structure. The proton conductivity of the dehydrated form increases by 24 times as a result of the in situ adsorption of methanol molecules, demonstrating the dual functionality of the framework. NMR studies revealed a hydrogen-bond interaction between the framework and methanol, which enables the modulation of proton conductivity within the framework. PMID:23829398

Umeyama, Daiki; Horike, Satoshi; Inukai, Munehiro; Kitagawa, Susumu

2013-07-18

206

Precise electrochemical control of ferromagnetism in a cyanide-bridged bimetallic coordination polymer.  

PubMed

Magnetic coordination polymers can exhibit controllable magnetism by introducing responsiveness to external stimuli. This report describes the precise control of magnetism of a cyanide-bridged bimetallic coordination polymer (Prussian blue analogue: PBA) through use of an electrochemical quantitative Li ion titration technique, i.e., the galvanostatic intermittent titration technique (GITT). K(0.2)Ni[Fe(CN)(6)](0.7)4.7H(2)O (NiFe-PBA) shows Li ion insertion/extraction reversibly accompanied with reversible Fe(3+)/Fe(2+) reduction/oxidation. When Li ion is inserted quantitatively into NiFe-PBA, the ferromagnetic transition temperature T(C) gradually decreases due to reduction of paramagnetic Fe(3+) to diamagnetic Fe(2+), and the ferromagnetic transition is completely suppressed for Li(0.6)(NiFe-PBA). On the other hand, T(C) increases continuously as Li ion is extracted due to oxidation of diamagnetic Fe(2+) to paramagnetic Fe(3+), and the ferromagnetic transition is nearly recovered for Li(0)(NiFe-PBA). Furthermore, the plots of T(C) as a function of the amount of inserted/extracted Li ion x are well consistent with the theoretical values calculated by the molecular-field approximation. PMID:22978515

Mizuno, Yoshifumi; Okubo, Masashi; Kagesawa, Koichi; Asakura, Daisuke; Kudo, Tetsuichi; Zhou, Haoshen; Oh-ishi, Katsuyoshi; Okazawa, Atsushi; Kojima, Norimichi

2012-09-14

207

Model system for a one-dimensional magnetic photonic crystal.  

PubMed

We fabricate and characterize one-dimensional magnetic (rather than dielectric) photonic crystals for the first time. Our model system is a one-dimensional periodic lattice of gold-wire pairs. Each pair can be viewed as a magnetic coil with two slits and represents a "magnetic atom." Strong coupling between the resulting magnetic-dipole resonance and the Bragg resonance is accomplished by an adjacent dielectric slab waveguide, giving rise to an avoided crossing at near-infrared wavelengths. Our experimental findings are in excellent agreement with theory. PMID:17026307

Linden, S; Decker, M; Wegener, M

2006-08-25

208

Random registry shifts in quasi-one-dimensional adsorbate systems  

SciTech Connect

The apparent contradiction of one-dimensional adsorbate chains on Si(111) having a 3x2 unit cell and yet a 3x1 diffraction pattern is resolved for the example of Ba/Si(111)-(3x2). Random registry shifts between adsorbate chains are observed in tunneling microscopy, with very short interchain correlation lengths. Fourier analysis provides a natural explanation for a pseudo-(3x1) diffraction pattern. Within density-functional theory such registry shifts can occur with essentially negligible energy cost, leading to entropy-driven, virtually perfect disorder. Substrate states of high symmetry and one-dimensional character are inferred to promote this phenomenon.

Schafer, J.; Erwin, S.C.; Hansmann, M.; Song, Z.; Rotenberg, E.; Kevan, S.D.; Hellberg, C.S.; Horn, K.

2003-02-18

209

Equilibration of a one-dimensional quantum liquid  

NASA Astrophysics Data System (ADS)

We review some of the recent results on equilibration of one-dimensional quantum liquids. The low-energy properties of these systems are described by the Luttinger liquid theory, in which the excitations are bosonic quasiparticles. At low temperatures, the relaxation of the gas of excitations toward full equilibrium is exponentially slow. In electronic Luttinger liquids, these relaxation processes involve backscattering of electrons and give rise to interesting corrections to the transport properties of one-dimensional conductors. We focus on the phenomenological theory of the equilibration of a quantum liquid and obtain an expression for the relaxation rate in terms of the excitation spectrum.

Matveev, K. A.

2013-09-01

210

Adiabaticity and Localization in One-Dimensional Incommensurate Lattices  

SciTech Connect

We experimentally investigate the role of localization on the adiabaticity of loading a Bose-Einstein condensate into a one-dimensional optical potential comprised of a shallow primary lattice plus one or two perturbing lattice(s) of incommensurate period. We find that even a very weak perturbation causes dramatic changes in the momentum distribution and makes adiabatic loading of the combined lattice much more difficult than for a single period lattice. We interpret our results using a band-structure model and the one-dimensional Gross-Pitaevskii equation.

Edwards, E. E.; Beeler, M.; Hong, Tao; Rolston, S. L. [Joint Quantum Institute and Department of Physics, University of Maryland, National Institute of Standards and Technology, College Park, Maryland 20742 (United States)

2008-12-31

211

Adiabaticity and localization in one-dimensional incommensurate lattices.  

PubMed

We experimentally investigate the role of localization on the adiabaticity of loading a Bose-Einstein condensate into a one-dimensional optical potential comprised of a shallow primary lattice plus one or two perturbing lattice(s) of incommensurate period. We find that even a very weak perturbation causes dramatic changes in the momentum distribution and makes adiabatic loading of the combined lattice much more difficult than for a single period lattice. We interpret our results using a band-structure model and the one-dimensional Gross-Pitaevskii equation. PMID:19437625

Edwards, E E; Beeler, M; Hong, Tao; Rolston, S L

2008-12-31

212

Normal and generalized Bose condensation in traps: One dimensional examples  

Microsoft Academic Search

We prove the following results. (i) One-dimensional Bose gases which interact\\u000avia unscaled integrable pair interactions and are confined in an external\\u000apotential increasing faster than quadratically undergo a complete generalized\\u000aBose-Einstein condensation (BEC) at any temperature, in the sense that a\\u000amacroscopic number of particles are distributed on a o(N)number of one-particle\\u000astates. (ii) In a one dimensional harmonic

Andras Suto

2003-01-01

213

Interference of parametrically driven one-dimensional ultracold gases  

SciTech Connect

We theoretically analyze interference patterns of parametrically driven one-dimensional ultracold atomic gases. By modulating the interaction strength periodically in time, we propose to excite collective modes in a pair of independent one-dimensional gases at energies corresponding to the drive frequency. The excited collective modes lead to spatial oscillations in the correlations of the interference pattern, which can be analyzed to obtain the sound velocity of the collective modes. We discuss both bosonic and fermionic systems and how such experiments could be used to probe spin-charge separation.

Pielawa, Susanne [Physics Department, Harvard University, Cambridge, Massachusetts 02138 (United States)

2011-01-15

214

Metalation studies of 3- and 4-pyridyloxycyclophosphazenes: metallamacrocycles to coordination polymers.  

PubMed

Pyridyloxy cyclophosphazenes, spiro-N3P3(O2C12H8)(O-C5H4N-3)4 (L1), dispiro-N3P3(O2C12H8)2(O-C5H4N-3)2 (L2) and dispiro-N3P3(O2C12H8)2(O-C5H4N-4)2 (L3) were prepared and characterized. The crystal structure of L1 was determined which showed that the cyclophosphazene ring is planar. The reaction of L1 with anhydrous copper(II) chloride or silver nitrate afforded L2M4 metallamacrocycles [{L1}2{ClCu(?-Cl)2CuCl}]28CHCl3 (3) and [{L1}2{(DMF)0.5(NO3)0.5Ag}2{Ag(?2-(O)NO2)(H2O)}2]{?-[NO3]}CH3OH (4) respectively. The molecular structure of 3 reveals that two CuCl2 dimers are bridged to each other in a complex metallamacrocycle that involves four metal ions and two ligands. The molecular structure of 4 is similar to that of 3 except for the presence of weak argentophilic interactions between the two Ag(I) centers. Also, a nitrate anion, which is trapped in the centre of the tetrameric assembly, assists in holding two Ag(I) ions together and 4 serves as a single source precursor for silver nanoparticles. The reaction L1 with ZnCl2 and Cd(NO3)24H2O afforded the 1D-coordination polymers [{L1}{ZnCl2}2]n2nCH3OH2nH2O (5) and [{L1}2{Cd(CH3OH)2(NO3)2}2{Cd(NO3)2(H2O)}]n3nCH3OH3nH2O (6) respectively. While in 5 the 20-membered macrocycles are inter-connected directly, in 6 they are bridged by a Cd(II) connector. The reaction of L2 with CoCl2 afforded the 1D-coordination polymer [{L2}2{CoCl2}]n2nCHCl3 (7) which also contains interconnected 20-membered metallamacrocycles. On the other hand, the reaction of L2 with CuCl2 afforded [{L2}2{ClCu(?-Cl)}2]n2nCHCl3nH2O (8) which is a 1D-coordination polymer that contains {ClCu(?-Cl)2CuCl} units. The reaction of L3 with CuCl2 and Cd(NO3)24H2O afforded [{L3}2{CuCl2}]nnDMF (9) and [{L3}2{Cd(NO3)2}]nnCHCl3nCH2Cl2nH2O (10) respectively. While 9 is a 2D-coordination polymer containing 48-membered metallamacrocycles, 10 is a 1D-coordination polymer containing interconnected 24-membered metallamacrocycles which possess spirocyclic cadmium ions as nodes. PMID:23478470

Chandrasekhar, Vadapalli; Narayanan, Ramakirushnan Suriya

2013-05-14

215

Localized cell stimulation by nitric oxide using a photoactive porous coordination polymer platform.  

PubMed

Functional cellular substrates for localized cell stimulation by small molecules provide an opportunity to control and monitor cell signalling networks chemically in time and space. However, despite improvements in the controlled delivery of bioactive compounds, the precise localization of gaseous biomolecules at the single-cell level remains challenging. Here we target nitric oxide, a crucial signalling molecule with site-specific and concentration-dependent activities, and we report a synthetic strategy for developing spatiotemporally controllable nitric oxide-releasing platforms based on photoactive porous coordination polymers. By organizing molecules with poor reactivity into polymer structures, we observe increased photoreactivity and adjustable release using light irradiation. We embed photoactive polymer crystals in a biocompatible matrix and achieve precisely controlled nitric oxide delivery at the cellular level via localized two-photon laser activation. The biological relevance of the exogenous nitric oxide produced by this strategy is evidenced by an intracellular change in calcium concentration, mediated by nitric oxide-responsive plasma membrane channel proteins. PMID:24158008

Diring, Stphane; Wang, Dan Ohtan; Kim, Chiwon; Kondo, Mio; Chen, Yong; Kitagawa, Susumu; Kamei, Ken-Ichiro; Furukawa, Shuhei

2013-10-25

216

1D + 1D ? 1D polyrotaxane, 2D + 2D ? 3D interpenetrated, and 3D self-penetrated divalent metal terephthalate bis(pyridylformyl)piperazine coordination polymers.  

PubMed

Divalent metal coordination polymers containing terephthalate (tere) and bis(4-pyridylformyl)piperazine (bpfp) show diverse and interesting two-dimensional (2D) interpenetrated, three-dimensional (3D) self-penetrated, or one-dimensional (1D) polyrotaxane topological features. Isostructural {[M(tere)(bpfp)(H(2)O)(2)]4H(2)O}(n) phases (1, Zn; 2, Co) exhibit mutually inclined 2D + 2D ? 3D interpenetration of gridlike layers. {[Cd(4)(tere)(4)(bpfp)(3)(H(2)O)(2)]8H(2)O}(n) (3) possesses a novel 3,4,8-connected trinodal self-penetrated network with (4.6(2))(2)(4(2)6(16)8(7)10(3))(4(2)6(4))(2) topology. [Zn(2)Cl(2)(tere)(bpfp)(2)](n) (4) is the first example of a 1D + 1D ? 1D polyrotaxane coordination polymer, to the best of our knowledge. Metal coordination geometry plays a crucial role in dictating the overall dimensionality in this system. Thermal decomposition behavior and luminescent properties of the d(10) configuration metal derivatives are also presented herein. PMID:21776990

Wang, Curtis Y; Wilseck, Zachary M; LaDuca, Robert L

2011-07-21

217

Image simulator for one-dimensional synthetic aperture microwave radiometer  

Microsoft Academic Search

Calibration for a one-dimensional synthetic aperture microwave radiometer is critical. Phase and amplitude calibration of the visibility samples must be carried out to compensate for system bias before measurement. This bias mainly comes from the un-uniform characteristics and the couplings between the receiving channels. To take into account this problem, a numerical image retrieving method is considered using an intermediate

Wu Qiong; Liu Hao; Wu Ji

2004-01-01

218

Modeling and perception of deformable one-dimensional objects  

Microsoft Academic Search

Recent advances in the modeling of deformable one-dimensional objects (DOOs) such as surgical suture, rope, and hair show significant promise for improving the simulation, perception, and manipulation of such objects. An important application of these tasks lies in the area of medical robotics, where robotic surgical assistants have the potential to greatly reduce surgeon fatigue and human error by improving

Shervin Javdani; Sameep Tandon; Jie Tang; James F. O'Brien; Pieter Abbeel

2011-01-01

219

Kinetic Instabilities in the Growth of One Dimensional Molecular Nanostructures  

Microsoft Academic Search

We develop a theory for the growth of one dimensional (1D) chains stabilized by anisotropic interactions, such as hydrogen bonding. Molecular chains are nucleated, grow, and may then undergo a kinetically driven transition to a two dimensional morphology. Kinetic Monte Carlo simulations show that extended 1D growth occurs between two temperature limits determined by two distinct kinetic instabilities. The limiting

J. Ben Taylor; Peter H. Beton

2006-01-01

220

Transient wave propagation in a one-dimensional poroelastic column  

Microsoft Academic Search

Summary Biot's theory of porous media governs the wave propagation in a porous, elastic solid infiltrated with fluid. In this theory, a second compressional wave, known as the slow wave, has been identified. In this paper, Biot's theory is applied to a one-dimensional continuum. Despite the simplicity of the geometry, an exact solution of the full model, and a detailed

M. Schanz; A. H.-D. Cheng

2000-01-01

221

SIMPLE ONE-DIMENSIONAL TRANSPORT CODE FOR MAGNETIZED TARGET FUSION  

SciTech Connect

A one-dimensional (in space) time-dependent simulation code is development to study the transport of energy and particles in a field reversed configuration (FRC) plasma that is undergoing radial contraction. This contraction is due to an imploding metallic liner, which is treated through a boundary condition.

STEFANO MIGLUIOLO - MIT

1999-10-30

222

One-dimensional extended Hubbard model in the atomic limit  

Microsoft Academic Search

We present the exact solution of the one-dimensional extended Hubbard model in the atomic limit within the Green's function and equations of motion formalism. We provide a comprehensive and systematic analysis of the model by considering all the relevant response and correlation functions as well as thermodynamic quantities in the whole parameters space. At zero temperature we identify four phases

F. Mancini

2008-01-01

223

Local Pair Correlations in One-Dimensional Bose Gases  

SciTech Connect

We measure photoassociation rates in one-dimensional Bose gases, and so determine the local pair correlation function over a wide range of coupling strengths. As bosons become more strongly coupled, we observe a tenfold decrease in their wave function overlap, thus directly observing the fermionization of bosons.

Kinoshita, Toshiya; Wenger, Trevor; Weiss, David S. [Department of Physics, The Pennsylvania State University, 104 Davey Lab, University Park, Pennsylvania, 16802 (United States)

2005-11-04

224

The Long Decay Model of One-Dimensional Projectile Motion  

ERIC Educational Resources Information Center

|This article introduces a research study on student model formation and development in introductory mechanics. As a point of entry, I present a detailed analysis of the Long Decay Model of one-dimensional projectile motion. This model has been articulated by Galileo ("in De Motu") and by contemporary students. Implications for instruction are

Lattery, Mark Joseph

2008-01-01

225

Numerical Computation of One-Dimensional Unsteady Flow in Channels.  

National Technical Information Service (NTIS)

A numerical technique used in gasdynamics is here applied to the solution of one-dimensional unsteady flows in channels using the shallow water theory. Its most important feature is the explicit treatment of imbedded bores generated in the flow by coalesc...

M. Pandolfi

1973-01-01

226

The Long Decay Model of One-Dimensional Projectile Motion  

Microsoft Academic Search

This article introduces a research study on student model formation and development in introductory mechanics. As a point\\u000a of entry, I present a detailed analysis of the Long Decay Model of one-dimensional projectile motion. This model has been\\u000a articulated by Galileo (in De Motu) and by contemporary students. Implications for instruction are discussed.

Mark Joseph Lattery

2008-01-01

227

The Long Decay Model of One-Dimensional Projectile Motion  

Microsoft Academic Search

This article introduces a research study on student model formation and development in introductory mechanics. As a point of entry, I present a detailed analysis of the Long Decay Model of one-dimensional projectile motion. This model has been articulated by Galileo (in De Motu) and by contemporary students. Implications for instruction are discussed.

Mark Joseph Lattery

2008-01-01

228

Analysis of paper pressing : the saturated one-dimensional case  

Microsoft Academic Search

We derive a one-dimensional model that describes pressing of water saturated paper in the press-section of the paper ma- chine. The model involves two nonlinear diffusion equations which are coupled across an internal boundary. Existence and uniqueness as a number of qualitative properties are demonstrated. Further, computational results for some concrete cases are discussed. 1 Introduction and motivation In paper

D Bezanovic; Duijn van CJ; E. F. Kaasschieter

2006-01-01

229

Segregation in a one-dimensional model of interacting species  

Microsoft Academic Search

We investigate segregation and spatial organization in a one-dimensional system of N competing species forming a cyclic food chain. For N < 5, the system organizes into single-species domains, with an algebraically growing average size. For N = 3 and N = 4, the domains are correlated and they organize into \\\\superdomains\\

L. Frachebourg; P. L. Krapivsky; E. Ben-Naim

230

Generalized approach to one-dimensional internal gas dynamics  

NASA Astrophysics Data System (ADS)

A general investigation is presented dealing with one-dimensional internal compressible flow accounting for internal friction, changes in duct area and potential energy, and considering energy transfer as heat and shaft work. The appropriate generalized equation can be applied to a specific case such as isentropic nozzle flow, Fanno flow, or Rayleigh flow to obtain the usual gas dynamic relations.

Scesa, S.

231

Reflection properties of one dimensional plasma photonic crystal  

NASA Astrophysics Data System (ADS)

In this paper band structure and reflection properties of on one-dimensional plasma photonic crystal (PPC) containing alternate layers of dielectric and micro-plasma have been presented. For the purpose of computation, transfer matrix method has been used. It is found that width of the forbidden band gap(s) can be increased by increasing the thickness of plasma layers.

Kumar, Arun; Khundrakpam, Pinky; Sharma, Priyanka

2013-06-01

232

Time Correlation Study of a One Dimensional Gravitating System  

Microsoft Academic Search

The past three decades have seen several groups investigate the dynamics of one dimensional self gravitating systems using both theoretical and numerical means. As of yet no one has come to any satisfactory conclusions concerning the existence of possible equilibrium states, and the time scale on which they may be approached. This simple gravitational system consists of parallel sheets of

Kenneth R. Yawn; Bruce N. Miller

1999-01-01

233

Approximate Approaches to the One-Dimensional Finite Potential Well  

ERIC Educational Resources Information Center

|The one-dimensional finite well is a textbook problem. We propose approximate approaches to obtain the energy levels of the well. The finite well is also encountered in semiconductor heterostructures where the carrier mass inside the well (m[subscript i]) is taken to be distinct from mass outside (m[subscript o]). A relevant parameter is the mass

Singh, Shilpi; Pathak, Praveen; Singh, Vijay A.

2011-01-01

234

NUMERICAL CALCULATION OF PRECURSOR FIELDS IN ONE DIMENSIONAL PHOTONIC CRYSTAL  

Microsoft Academic Search

The presence of superluminal (in excess of the speed of light in vacuum) or negative group velocities in passive or active Lorentzian medium, one-dimensional photonic crys- tal (1DPC), undersized waveguide, and other structures has been theoretically predicted and experimentally observed. While due to the temporal or structural dispersions the group velocity in these media is abnormal, it has been ar-

Reza Safian; Costas D. Sarris; Mohammad Mojahedi

235

Gravitational force in an infinite one-dimensional Poisson distribution  

Microsoft Academic Search

We consider the statistical properties of the gravitational field F in an infinite one-dimensional homogeneous Poisson distribution of particles using an exponential cutoff of the pair interaction to control and study the divergences which arise. Deriving an exact analytic expression for the probability density function (PDF) P(F) , we show that it is badly defined in the limit in which

Andrea Gabrielli; Michael Joyce

2010-01-01

236

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...

237

Detecting Natural ``Plateaus'' in One-Dimensional Patterns  

Microsoft Academic Search

A method of detecting natural ``plateaus'' (equals maximal intervals of approximately constant value) in a one-dimensional pattern is described. The method is based on examining neighborhoods of each point having a range of sizes; rejecting neighborhoods of each size for which the standard deviation (of pattern values over the neighborhood) is not a local minimum; and further rejecting any neighborhood

Andrew F. Blumenthal; Larry S. Davis; Azriel Rosenfeld

1977-01-01

238

Study of the disordered one-dimensional contact process  

Microsoft Academic Search

New theoretical and numerical analysis of the one-dimensional contact pro- cess with quenched disorder are presented. We derive new scaling relations, different from their counterparts in the pure model, which are valid not only at the critical point but also away from it due to the presence of generic scale invariance. All the proposed scaling laws are verified in numerical

Raffaele Cafiero; Andrea Gabrielli; Miguel A. Munoz

239

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

240

Friedel-Type Oscillations in One-Dimensional Antiferromagnetic Insulators.  

National Technical Information Service (NTIS)

An impurity spin in one-dimensional spin-half X-Y and antiferromagnetic Heisenberg models is shown to induce decaying spatial oscillations of magnetization for finite magnetic field. In zero field there are no oscillations but only decay. Since these syst...

G. Baskaran

1978-01-01

241

Power-Law Localization in One-Dimensional Random Potentials.  

National Technical Information Service (NTIS)

The energy spectrum of particle in a one-dimensional Kronig-Penney of length L is studied. The transfer matrix approach is used to calculate the transmission coefficient T. In particular it is found that at certain isolated energies the states are not exp...

A. Brezini M. Sebbani F. Behilil

1985-01-01

242

A difference characteristic for one-dimensional deterministic systems  

NASA Astrophysics Data System (ADS)

A numerical characteristic for one-dimensional deterministic systems reflecting its higher order difference structure is introduced. The comparison with Lyapunov exponent is given. A difference analogy for Eggleston theorem as well as an estimate for Hausdorff dimension of the difference attractor, formulated in terms of the new characteristic is proved.

Shahverdian, A. Yu.; Apkarian, A. V.

2007-06-01

243

One-dimensional models for blood flow in arteries  

Microsoft Academic Search

In this paper a family of one-dimensional nonlinear systems which model the blood pulse propagation in compliant arteries is presented and investigated. They are obtained by averaging the Navier-Stokes equation on each section of an arterial vessel and using simplified models for the vessel compliance. Different differential operators arise depending on the simplifications made on the structural model. Starting from

Luca Formaggia; Daniele Lamponi; Alfio Quarteroni

2003-01-01

244

Global Orbit Patterns for One Dimensional Dynamical Systems  

Microsoft Academic Search

In this article, we study the behaviour of discrete one-dimensional dynamical systems associated to functions on finite sets. We formalise the global orbit pattern formed by all the periodic orbits (gop) as the ordered set of periods when the initial value thumbs the finite set in the increasing order. We are able to predict, using closed formulas, the number of

Rene Lozi; Clarisse Fiol

2009-01-01

245

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

246

Consolidation and Rebound Processes in One-Dimensional Porous columns  

Microsoft Academic Search

The present paper analyzes the consolidation and rebound processes of one-dimensional porous columns as they relate to petroleum production operations. Darcy's law and its implication for a mobile matriare discussed. The specific problem considered is the shrinkage or expansion of a porous system to a single step function change in pressure at the base of the column, which may be

R. Raghavan

1974-01-01

247

Conservation laws in the one-dimensional Hubbard model  

Microsoft Academic Search

We examine the nature, number, and interrelation of conservation laws in the one-dimensional Hubbard model. In previous work by Shastry [Phys. Rev. Lett. 56, 1529 (1986); 56, 2334 (1986); 56, 2453 (1986); J. Stat. Phys. 50, 57 (1988)], who studied the model on a large but finite number of lattice sites (Na), only Na+1 conservation laws, corresponding to Na+1 operators

J. M. Carmelo; T. Prosen; D. K. Campbell

2001-01-01

248

Dynamics of Excitations in a One-Dimensional Bose Liquid  

SciTech Connect

We show that the dynamic structure factor of a one-dimensional Bose liquid has a power-law singularity defining the main mode of collective excitations. Using the Lieb-Liniger model, we evaluate the corresponding exponent as a function of the wave vector and the interaction strength.

Khodas, M.; Glazman, L. I. [William I. Fine Theoretical Physics Institute and School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Pustilnik, M. [School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Kamenev, A. [School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

2007-09-14

249

The Long Decay Model of One-Dimensional Projectile Motion  

NASA Astrophysics Data System (ADS)

This article introduces a research study on student model formation and development in introductory mechanics. As a point of entry, I present a detailed analysis of the Long Decay Model of one-dimensional projectile motion. This model has been articulated by Galileo (in De Motu) and by contemporary students. Implications for instruction are discussed.

Lattery, Mark Joseph

2008-08-01

250

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

251

Pyridine-2,4-dicarboxylate: a versatile building block for the preparation of functional coordination polymers.  

PubMed

The hydrothermal reaction of the pyridine-2,4-dicarboxylate (2,4-pdc) dianion with various 3d metal(II) cations resulted in the formation of a series of one-, two- and three-dimensional coordination polymers with varied network topologies. 2,4-pdc reacted directly with MnCI2 or FeCl2 in water at 200 degrees C under mild basic conditions to give a dense three-dimensional polymer, [M(2,4-pdc)] (M = Mn, 1a; M = Fe, 1b), which supports a highly-connected three-dimensional magnetic exchange lattice. Both 1a and 1b undergo antiferromagnetic ordering and the latter Fe(II)-containing material exhibited spin-canting behavior below 6.5 K. Reaction of 2,4-pdc with CoCl2 under identical conditions gave an unusual zigzag chain polymer, [Co4(2,4-pdc)4(OH2)10] (2), that has large amounts of coordinated H2O. The magnetism of 2 based on isolated Co(II) dimers was modeled using a modified van Vleck approach. Adjustment of the reaction pH resulted in the formation of additional Co(II)-containing materials with strongly contrasting structures: at lower pH in the presence of oxalic acid, the same reaction components gave a protonated molecular species, [Co(2,4-pdcH)2(OH2)2]. 2H2O (3); at higher pH in the presence of excess hydroxide, a highly porous, three-dimensional material was obtained, [Co3(micro3-OH)2(2,4-pdc)2] x 9H2O (4a). 4a contains cobalt hydroxide chains, whose magnetic behavior has been studied in detail by neutron diffraction. A Ni(II)-containing analogue was also prepared using NiCI2 (4b), which shows weak antiferromagnetic coupling. Attempts to obtain a Zn(II)-based analogue of the porous material 4 gave instead a unique coordination material, [Zn(micro2-OH)2(2,4-pdc)] (5), which contains uncommon zinc hydroxide bridging modes. PMID:20352809

Humphrey, Simon M; Weldon, Gerald F; Wood, Paul T

2010-01-01

252

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

253

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

SciTech Connect

The hydrothermal reactions of isonicotinic acid (HIso) and metal salts yielded two novel 3-D coordination polymers {l_brace}[Cu{sub 4}(Iso){sub 4}({mu} {sub 3}-O){sub 2}(C{sub 2}H{sub 5}OH){sub 2}].2C{sub 2}H{sub 5}OH.C{sub 2}H{sub 6}N{sub 4}{r_brace} {sub n} (1), {l_brace}[Cd(Iso){sub 2}(H{sub 2}O)].OHCCHO{r_brace} {sub 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 [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)]. E-mail: bliu_1203@yahoo.com.cn; Xu Ling [Department of Chemistry, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Guo Guocong [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

2006-03-15

254

Rare Earth coordination polymers with zeolite topology constructed from 4-connected building units.  

PubMed

A series of rare earth coordination polymers, M(BTC)(DMF)(DMSO) (M = Tb (1), Ho (2), Er (3), Yb (4), Y (5)), with zeolite ABW topology have been synthesized under mild conditions. They exhibit the same three-dimensional (3D) architecture and crystallize in monoclinic symmetry space group P2(1)/n. Their structures are built up from inorganic and organic 4-connected building units, whose vertex symbols are 4.4.6.6.6.8. The building units link to each other to generate approximate 5 x 8 angstroms2 channels along the [100] direction. The luminescent and magnetic properties of these compounds are investigated, and the results reveal that they could be anticipated to be potential antiferromagnetic and fluorescent materials. PMID:16676967

Guo, Xiaodan; Zhu, Guangshan; Li, Zhongyue; Chen, Yan; Li, Xiaotian; Qiu, Shilun

2006-05-15

255

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

256

Modular design of domain assembly in porous coordination polymer crystals via reactivity-directed crystallization process.  

PubMed

The mesoscale design of domain assembly is crucial for controlling the bulk properties of solids. Herein, we propose a modular design of domain assembly in porous coordination polymer crystals via exquisite control of the kinetics of the crystal formation process. Employing precursors of comparable chemical reactivity affords the preparation of homogeneous solid-solution type crystals. Employing precursors of distinct chemical reactivity affords the preparation of heterogeneous phase separated crystals. We have utilized this reactivity-directed crystallization process for the facile synthesis of mesoscale architecture which are either solid-solution or phase-separated type crystals. This approach can be also adapted to ternary phase-separated type crystals from one-pot reaction. Phase-separated type frameworks possess unique gas adsorption properties that are not observed in single-phasic compounds. The results shed light on the importance of crystal formation kinetics for control of mesoscale domains in order to create porous solids with unique cooperative functionality. PMID:22816727

Fukushima, Tomohiro; Horike, Satoshi; Kobayashi, Hirokazu; Tsujimoto, Masahiko; Isoda, Seiji; Foo, Maw Lin; Kubota, Yoshiki; Takata, Masaki; Kitagawa, Susumu

2012-08-06

257

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

258

Synthesis, crystal structures, and luminescence properties of carboxylate based rare-earth coordination polymers.  

PubMed

Rare-earth coordination polymers or lanthanide-organic frameworks with hitherto unreported crystal structures have been obtained on the basis of the "light" lanthanides Pr, Nd, Sm, and Eu in combination with terephthalic acid and using a slightly altered literature synthesis procedure. Rietveld refinement has shown that powder XRD patterns of such compounds are largely dominated by the positions of the heavy elements, pointing to isostructural networks for all four terephthalate-based materials. An in-depth luminescence study has been performed on the reported MOFs, showing rare praseodymium and samarium emission in the visible spectrum, aside from the strong europium luminescence and the near-infrared emission from both a terephthalate and 2,5-pyridinedicarboxylate based neodymium-MOF. PMID:23078525

Decadt, Roel; Van Hecke, Kristof; Depla, Diederik; Leus, Karen; Weinberger, David; Van Driessche, Isabel; Van Der Voort, Pascal; Van Deun, Rik

2012-10-18

259

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

260

Influence of steric hindrance of organic ligand on the structure of Keggin-based coordination polymer.  

PubMed

Five Keggin-based 3D coordination polymers, namely, [Cu3(pz)3(PW12O40)] (pz = pyrazine) (1), [Cu3(2,3-Me2pz)3(PW12O40)] (2,3-Me2pz = 2,3-dimethylpyrazine) (2), [Cu2(2,5-Me2pz)(1.5)(2,5-HMe2pz)(PW12O40)] (2,5-Me2pz = 2,5-dimethylpyrazine) (3), [Cu3(2,3-Me2pz)3(PMo12O40)] (4), and [Ag3(pz)3(PW12O40)].0.5H2O (5), were synthesized and structurally characterized. Crystal data are as follows: trigonal, space group R3c, a = 18.4070(14) angstroms, c = 22.544(3) angstroms, gamma = 120 degrees, and Z = 6 for 1; orthorhombic, space group Pccn, a = 16.599(2) angstroms, b = 20.470(3) angstroms, c = 14.3757(18) angstroms, and Z = 4 for 2; triclinic, space group P1, a = 10.667(2) angstroms, b = 11.147(2) angstroms, c = 20.207(4) angstroms, alpha = 90.983(4) degrees, beta = 108.128(3) degrees, gamma = 92.150(4) degrees, and Z = 2 for 3; orthorhombic, space group Pccn, a = 16.450(3) angstroms, b = 20.170(4) angstroms, c = 14.244(3) angstroms, and Z = 4 for 4; and rhombohedral, space group R32, a = 18.2047(13) angstroms, c = 23.637(3) angstroms, gamma = 120 degrees, and Z = 6 for 5. Their structural differences were investigated using crystal structure analysis, revealing that the influence of steric hindrance of organic ligand on the structures of Keggin-based coordination polymers is realized through changing the number of metal-organic units surrounding the POM anion. PMID:16676962

Ren, Yan-Ping; Kong, Xiang-Jian; Hu, Xiang-Yang; Sun, Meng; Long, La-Sheng; Huang, Rong-Bin; Zheng, Lan-Sun

2006-05-15

261

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

SciTech Connect

Four new lanthanide coordination polymers, [Y(Hnip)(nip)(H{sub 2}O)].H{sub 2}O (1), [Ln(Hnip)(nip)(H{sub 2}O){sub 2}].2H{sub 2}O [Ln=Eu(2), Tb(3)] and [Y(nip){sub 2}].(H{sub 2}4,4'-bpy){sub 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{sub 2}(nip){sub 4}]{sup 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{sup 3+} ions at room temperature, and its luminescent lifetime and quantum efficiency has been determined. - Graphical abstract: Four lanthanide 5-nitroisophthalate coordination polymers have been hydrothermally prepared and resent different structures and thermal stabilities and photoluminescence properties.

Huang Yan [Department of Chemistry, Tongji University, Shanghai 200092 (China); Yan Bing, E-mail: byan@tongji.edu.c [Department of Chemistry, Tongji University, Shanghai 200092 (China); State Key Lab of Coordination Chemistry, Nanjing University, Nanjing 210093 (China); Shao Min [Department of Chemistry, College of Science, Shanghai University, Shanghai 200444 (China)

2009-04-15

262

The one-dimensional Coulomb lattice fluid capacitor.  

PubMed

The one-dimensional Coulomb lattice fluid in a capacitor configuration is studied. The model is formally exactly soluble via a transfer operator method within a field theoretic representation of the model. The only interactions present in the model are the one-dimensional Coulomb interaction between cations and anions and the steric interaction imposed by restricting the maximal occupancy at any lattice site to one particle. Despite the simplicity of the model, a wide range of intriguing physical phenomena arise, some of which are strongly reminiscent of those seen in experiments and numerical simulations of three-dimensional ionic liquid based capacitors. Notably, we find regimes where over-screening and density oscillations are seen near the capacitor plates. The capacitance is also shown to exhibit strong oscillations as a function of applied voltage. It is also shown that the corresponding mean-field theory misses most of these effects. The analytical results are confirmed by extensive numerical simulations. PMID:22897305

Dmery, Vincent; Dean, David S; Hammant, Thomas C; Horgan, Ronald R; Podgornik, Rudolf

2012-08-14

263

Thermodynamics of strongly correlated one-dimensional Bose gases  

NASA Astrophysics Data System (ADS)

We investigate the thermodynamics of one-dimensional (1D) Bose gases in the strongly correlated regime. To this end, we prepare ensembles of independent 1D Bose gases in a two-dimensional optical lattice and perform high-resolution in situ imaging of the column-integrated density distribution. Using an inverse Abel transformation we derive effective one-dimensional line-density profiles and compare them to exact theoretical models. The high resolution allows for a direct thermometry of the trapped ensembles. The knowledge about the temperature enables us to extract thermodynamic equations of state such as the phase-space density, the entropy per particle, and the local pair-correlation function.

Vogler, Andreas; Labouvie, Ralf; Stubenrauch, Felix; Barontini, Giovanni; Guarrera, Vera; Ott, Herwig

2013-09-01

264

Dynamics of one-dimensional Kerr cavity solitons.  

PubMed

We present an experimental observation of an oscillating Kerr cavity soliton, i.e., a time-periodic oscillating one-dimensional temporally localized structure excited in a driven nonlinear fiber cavity with a Kerr-type nonlinearity. More generally, these oscillations result from a Hopf bifurcation of a (spatially or temporally) localized state in the generic class of driven dissipative systems close to the 1 : 1 resonance tongue. Furthermore, we theoretically analyze dynamical instabilities of the one-dimensional cavity soliton, revealing oscillations and different chaotic states in previously unexplored regions of parameter space. As cavity solitons are closely related to Kerr frequency combs, we expect these dynamical regimes to be highly relevant for the field of microresonator-based frequency combs. PMID:23572006

Leo, Franois; Gelens, Lendert; Emplit, Philippe; Haelterman, Marc; Coen, Stphane

2013-04-01

265

One-dimensional Si nanolines in hydrogenated Si(001)  

NASA Astrophysics Data System (ADS)

We present a detailed study of the structural and electronic properties of a self-assembled silicon nanoline embedded in the H-terminated silicon (001) surface, known as the Haiku stripe. The nanoline is a perfectly straight and defect free endotaxial structure of huge aspect ratio; it can grow micrometre long at a constant width of exactly four Si dimers (1.54 nm). Another remarkable property is its capacity to be exposed to air without suffering any degradation. The nanoline grows independently of any step edges at tunable densities, from isolated nanolines to a dense array of nanolines. In addition to these unique structural characteristics, scanning tunnelling microscopy and density functional theory reveal a one-dimensional state confined along the Haiku core. This nanoline is a promising candidate for the long sought after electronic solid-state one-dimensional model system to explore the fascinating quantum properties emerging in such reduced dimensionality. Phys. Rev. B, 84, 035328 (2011)

Franois, Bianco; Kster, Sigrun A.; Owen, James G. H.; Renner, Christoph; Bowler, David R.

2012-02-01

266

Entanglement vs. gap for one-dimensional spin systems  

SciTech Connect

We study the relationship between entanglement and spectral gap for local Hamiltonians in one dimension. The area law for a one-dimensional system states that for the ground state, the entanglement of any interval is upper-bounded by a constant independent of the size of the interval. However, the possible dependence of the upper bound on the spectral gap {Delta} is not known, as the best known general upper bound is asymptotically much larger than the largest possible entropy of any model system previously constructed for small {Delta}. To help resolve this asymptotic behavior, we construct a family of one-dimensional local systems for which some intervals have entanglement entropy which is polynomial in 1/{Delta}, whereas previously studied systems had the entropy of all intervals bounded by a constant times log(1/{Delta}).

Hastings, Matthew [Los Alamos National Laboratory; Aharonov, Dorit [HEBREW UNIV; Gottesman, Daniel [PERIMETER INSTITUTE

2008-01-01

267

Assessing the inherent uncertainty of one-dimensional diffusions  

NASA Astrophysics Data System (ADS)

In this paper we assess the inherent uncertainty of one-dimensional diffusion processes via a stochasticity classification which provides an 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.

Eliazar, Iddo; Cohen, Morrel H.

2013-01-01

268

Two-step approach to one-dimensional anharmonic oscillators  

Microsoft Academic Search

We propose a two-step approach to one-dimensional anharmonic oscillators. A generalized coherent-state ansatz is introduced for the first step. A theorem of Wick's ordering and a Bogoliubov transformation are used to simplify the derivation. This is shown to be equivalent to the Hartree approximation. In the second step, standard diagonalization is used for the transformed Hamiltonian. The method yields a

Chen-Shiung Hsue; J. L. Chern

1984-01-01

269

Statistics of resonances in one-dimensional continuous systems  

Microsoft Academic Search

We study the average density of resonances (DOR) of a disordered one-dimensional continuous open system. The disordered system\\u000a is semi-infinite, with white-noise random potential, and it is coupled to the external world by a semi-infinite continuous\\u000a perfect lead. Our main result is an integral representation for the DOR which involves the probability density function of\\u000a the logarithmic derivative of the

Joshua Feinberg

2009-01-01

270

Few interacting fermions in a one-dimensional harmonic trap  

NASA Astrophysics Data System (ADS)

We study spin-1/2 fermions, interacting via a two-body contact potential, in a one-dimensional harmonic trap. Applying exact diagonalization, we investigate their behavior at finite interaction strength and discuss the role of the ground-state degeneracy which occurs for sufficiently strong repulsive interaction. Even low temperature or a completely depolarizing channel may then dramatically influence the system's behavior. We calculate level occupation numbers as signatures of thermalization, and we discuss the mechanisms to break the degeneracy.

Sowi?ski, Tomasz; Grass, Tobias; Dutta, Omjyoti; Lewenstein, Maciej

2013-09-01

271

Localization in a Quasi-Periodic One Dimensional System  

Microsoft Academic Search

We study mobility edges and Anderson-like localization in a disorder-free, one-dimensional quasi-periodic system. In particular, we study a bichromatic sinusoidal lattice potential where a primary periodic lattice is perturbed by a secondary lattice with a period that is incommensurate with that of the primary lattice. This interesting potential admits both extended and localized states without the presence of disorder. We

John Biddle; Donald Priour; Sankar Das Sarma

2009-01-01

272

Two-state one-dimensional spinless Fermi gas  

SciTech Connect

The two-state, one-dimensional, spinless Fermi gas (Falicov-Kimball model) is studied exactly by numerical calculation and perturbation theory. Rigorous results are presented for small interaction strength and (restricted) coherent and incoherent phase diagrams are calculated for two specific examples. The numerical calculations are extrapolated to provide a qualitative picture of the complete solution. The result includes a fractal structure in which the ground-state changes discontinuously as a function of the parameters.

Freericks, J.K.; Falicov, L.M. (Department of Physics, University of California at Berkeley, Berkeley, California 94720 (USA) Materials and Chemical Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (USA))

1990-02-01

273

Bosonic Hard-Rods in One Dimensional Optical Lattices  

NASA Astrophysics Data System (ADS)

Diffusion Monte Carlo simulations on the subject of bosonic hard rods trapped in one dimensional optical lattices are presented. The existence of Mott Insulator phases for integer fillings is deduced from the behavior of the energy per particle as a function of the density. The analysis of the pair distribution functions and structure factors suggest the existence of fluid-like phases for shallow optical lattices that evolve to solid-like arrangements when the confinement is deep enough.

de Soto, F.; Gordillo, M. C.

2013-05-01

274

Quasi-One-Dimensional Modeling of Hydrogen Fuelled Scramjet Combustors  

Microsoft Academic Search

A computationally efficient, quasi-one-dimensional supersonic combustion ramjet (scramjet) propulsion model has been produced to be used in hypersonic system design studies. The model uses a series of ordinary differential equations, solved using a 4th order Runga-Kutta method, to describe the gas dynamics within the scramjet duct. Additional models for skin friction and wall heat transfer are also included. The equations

Cristian Birzer

275

Statistical properties of one-dimensional attractive Bose gas  

NASA Astrophysics Data System (ADS)

Using the classical field approximation we present the first study of statistical properties of one-dimensional Bose gas with attractive interaction. The canonical probability distribution is generated with the help of a Monte Carlo method. This way we obtain not only the depletion of the condensate with growing temperature but also its fluctuations. The most important is our discovery of a reduced coherence length, the phenomenon observed earlier only for the repulsive gas, known as quasicondensation.

Bienias, P.; Paw?owski, K.; Gajda, M.; Rz??ewski, K.

2011-10-01

276

Quasi-one-dimensional magnons in an intermetallic marcasite.  

PubMed

We present inelastic neutron scattering measurements and first principles calculations examining the intermetallic marcasite CrSb(2). 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, we observe a clear anisotropic thermal conductivity indicating that the magnetic anisotropy enhances thermoelectric properties along particular crystallographic directions. PMID:22680752

Stone, M B; Lumsden, M D; Nagler, S E; Singh, D J; He, J; Sales, B C; Mandrus, D

2012-04-20

277

Integrable Kondo impurities in one-dimensional extended Hubbard models  

Microsoft Academic Search

Three kinds of integrable Kondo problems in one-dimensional extended Hubbard models are studied by means of the boundary graded quantum inverse scattering method. The boundary K matrices depending on the local moments of the impurities are presented as a nontrivial realization of the graded reflection equation algebras acting in a (2salpha+1)-dimensional impurity Hilbert space. Furthermore, these models are solved using

Huan-Qiang Zhou; Xiang-Yu Ge; Jon Links; Mark D. Gould

2000-01-01

278

On the Thermal Properties of Frohlich's One-Dimensional Superconductor  

Microsoft Academic Search

Frohlich has shown that a one-dimensional metal, at absolute zero, can exhibit certain of the properties of a superconductor when the interaction between the lattice vibrations and the electrons is sufficiently strong. The self-consistent method used by him is extended to finite temperatures, and the specific heat is calculated. It is shown that the model exhibits a second-order transition at

C. G. Kuper

1955-01-01

279

Quasi-one-dimensional steady-state cavitating nozzle flows  

Microsoft Academic Search

Quasi-one-dimensional cavitating nozzle flows are considered by employing a homogeneous bubbly liquid flow model. The nonlinear dynamics of cavitating bubbles is described by a modified Rayleigh Plesset equation that takes into account bubble\\/bubble interactions by a local homogeneous mean-field theory and the various damping mechanisms by a damping coefficient, lumping them together in the form of viscous dissipation. The resulting

C. F. Delale; G. H. Schnerr; J. Sauer

2001-01-01

280

Si(557)Ag: A metallic quasi-one-dimensional system  

Microsoft Academic Search

A quasi-one-dimensional (1D) system was fabricated by adsorbing one-fifth of a monolayer of Ag onto a Si(557) surface. Structural investigations performed with electron diffraction and scanning tunneling microscopy provided evidence of a midterrace row of Si adatoms with 2 periodicity along [110] , parallel to the step edges. A similar feature is also found in the Si(557)-Au system. Period doubling

J. A. Lipton-Duffin; A. G. Mark; J. M. MacLeod; A. B. McLean

2008-01-01

281

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

282

One-dimensional nanostructures for electronic and optoelectronic devices  

Microsoft Academic Search

One-dimensional (1-D) nanostructures have been the focus of current researches due to their unique physical properties and\\u000a potential applications in nanoscale electronics and optoelectronics. They address and overcome the physical and economic limits\\u000a of current microelectronic industry and will lead to reduced power consumption and largely increased device speed in next\\u000a generation electronics and optoelectronics. This paper reviews the recent

Guozhen Shen; Di Chen

2010-01-01

283

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

284

Thermodynamics of histories for the one-dimensional contact process  

Microsoft Academic Search

The dynamical activity K(t) of a stochastic process is the number of times it changes configuration up to time t. It was recently argued that (spin) glasses are at a first-order dynamical transition where histories of low and high activity coexist. We study this transition in the one-dimensional contact process by weighting its histories with exp(sK(t)). We determine the phase

Jef Hooyberghs; Carlo Vanderzande

2010-01-01

285

Fast Integration of One-Dimensional Boundary Value Problems  

NASA Astrophysics Data System (ADS)

Two-point nonlinear boundary value problems (BVPs) in both unbounded and bounded domains are solved in this paper using fast numerical antiderivatives and derivatives of functions of L2(-?, ?). This differintegral scheme uses a new algorithm to compute the Fourier transform. As examples we solve a fourth-order two-point boundary value problem (BVP) and compute the shape of the soliton solutions of a one-dimensional generalized Korteweg-de Vries (KdV) equation.

Campos, Rafael G.; Ruiz, Rafael Garca

2013-11-01

286

Recent progress in studies of one-dimensional gravitating systems  

Microsoft Academic Search

We review the results of recent investigations of the dynamics of one-dimensional gravitational systems carried out at Texas\\u000a Christian University. Two types of systems are considered: (1) parallel mass sheets of infinite spatial extent and (2) concentric,\\u000a spherically symmetric, irrotational mass shells confined between two rigid spherical barriers. By studying the kinetic energy\\u000a equipartition of a sheet system consisting of

Bruce N. Miller; Kenneth R. Yawn; V. Youngkins

287

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

288

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

289

Analysis of one-dimensional Helmholtz equation with PML boundary  

Microsoft Academic Search

In this paper, the linear conforming finite element method for the one-dimensional Brenger's PML boundary is investigated and well-posedness of the given equation is discussed. Furthermore, optimal error estimates and stability in the L2 or H1-norm are derived under the assumption that h, h2?2 and h2?3 are sufficiently small, where h is the mesh size and ? denotes a fixed

Taeyoung Ha; Imbunm Kim

2007-01-01

290

Semiclassical analysis of level widths for one-dimensional potentials  

NASA Astrophysics Data System (ADS)

We present a semiclassical study of level widths for a class of one-dimensional potentials in the presence of an ohmic environment. Using a semiclassical approach for the dipole matrix element we obtain the level widths within the golden rule approximation. For potentials with an asymptotic power-law behavior, which may in addition be limited by an infinite wall, we find a universal result: The level widths are proportional to the corresponding quantum number.

Ingold, Gert-Ludwig; Jalabert, Rodolfo A.; Richter, Klaus

2001-02-01

291

One-dimensional coagulation: Scaling and phase-separation dynamics  

Microsoft Academic Search

A simulation of a one-dimensional coagulating system of droplets with mass-dependent diffusion coefficients is presented. The total droplet density is shown to decay as t-1\\/3 and the density of droplets of mass l decays as exp(-ct1\\/3\\/l) in the long-time limit. Simple kinetic arguments are derived which predict these results. The scaling behavior and the similarity to phase-separation dynamics is investigated.

J. A. Marqusee

1987-01-01

292

Boundary Conditions in One-dimensional Tunneling Junction  

NASA Astrophysics Data System (ADS)

The tunneling effect is first characterized in quantum mechanics. However, the mathematical analysis for the tunneling effect is so complicated. In the conventional sense, the WKB analysis is useful to analyze such effect. Here, we consider the mathematical analysis for the tunneling effect in the one-dimensional Schrdinger system from the viewpoint of functional analysis. From the rigorous analysis, we obtain the interference pattern of the tunneling particle.

Shikano, Yutaka; Hirokawa, Masao

2011-07-01

293

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

294

Synthesis and applications of one-dimensional semiconductors  

Microsoft Academic Search

Nanoscale inorganic materials such as quantum dots (0-dimensional) and one-dimensional (1D) structures, such as nanowires, nanobelts and nanotubes, have gained tremendous attention within the last decade. Among the huge variety of 1D nanostructures, semiconducting nanowires have gained particular interest due to their potential applications in optoelectronic and electronic devices. Despite the huge efforts to control and understand the growth mechanisms

Sven Barth; Francisco Hernandez-Ramirez; Justin D. Holmes; Albert Romano-Rodriguez

2010-01-01

295

Conservation laws in the one-dimensional Hubbard model  

Microsoft Academic Search

We examine the nature, number, and interrelation of conservation laws in the one-dimensional Hubbard model. In previous work by Shastry [Phys. Rev. Lett. 56, 1529 (1986); 56, 2334 (1986); 56, 2453 (1986); J. Stat. Phys. 50, 57 (1988)], who studied the model on a large but finite number of lattice sites (N{sub a}), only N{sub a}+1 conservation laws, corresponding to

J. M. P. Carmelo; T. Prosen; D. K. Campbell

2001-01-01

296

Structure and magnetic properties of heterometallic coordination carboxylate polymers with cobalt and lithium atoms  

SciTech Connect

Reactions between lithium pivalate and cobalt coordination polymers [Co{sub 5}(OH{sub 2})(OH)(Piv){sub 9})L{sup 1}){sub 4}]{sub n} (I) and [Co{sub 2}(OH{sub 2})(Piv){sub 4}(L{sup 2}){sub 2}]{sub n} (II), where Piv-is the pivalate anion, L{sup 1} is pyrazine, and L{sup 2} is pyrimidine, result in new heterometallic polymers {l_brace}[Li{sub 2}Co{sub 2}(Piv){sub 6}(L{sup 1}){sub 2}]{sub 2}MeCN{r_brace}{sub n} (III), {l_brace}[Li{sub 2}Co{sub 2}(Piv){sub 6}(L{sup 2})]{sub 0.5}MeCN{r_brace}{sub n} (IV), and [Li{sub 2}Co{sub 2}(Piv){sub 6}(L{sup 2}){sub 2}]{sub n} (V). The resulting compounds contain tetra-nuclear {l_brace}Li{sub 2}Co{sub 2}(Piv){sub 6}{r_brace} fragments connected by neutral bridging ligands (pyrazine or pyrimidine) into layer structures. Crystal structures III-V are determined, and the magnetic properties of III and IV are studied.

Evstifeev, I. E.; Kiskin, M. A., E-mail: mkiskin@igic.ras.ru [Russian Academy of Sciences, Kurnakov Institute of General and Inorganic Chemistry (Russian Federation); Bogomyakov, A. S. [Russian Academy of Sciences, International Tomography Center, Siberian Branch (Russian Federation); Sidorov, A. A.; Novotortsev, V. M.; Eremenko, I. L. [Russian Academy of Sciences, Kurnakov Institute of General and Inorganic Chemistry (Russian Federation)

2011-09-15

297

Three-dimensional metal azide coordination polymers with amino carboxylate coligands: synthesis, structure, and magnetic properties.  

PubMed

The reaction of M(II) ions with azido ligands in the presence of different amino carboxylic acids gave four three-dimensional metal-azido coordination polymers, [Mn(3,5-daba)(N(3))](n) (1), [Cd(3,5-daba)(N(3))](n) (2; 3,5-daba = 3,5-diaminobenzoate), [Mn(4-aba)(N(3))](n) (3; 4-aba = 4-aminobenzoate), and [Cu(2)(gly)(2)(N(3))(2)](n) (4; gly = glycinate), which display different topological structures. Polymers 1 and 2 present 4,6-connected 3D networks with different Schlafli symbols. However, 3 and 4 feature an unprecedented trinodal 3,6-connected network with the Schlafli symbol (4(2).6)(4.6(2))(4(3).6(6).8(6)) and an unusual 4-connected 3D net with the Lonsdaleite (hexagonal diamond) topology, respectively. Magnetic susceptibility measurements revealed dominant antiferromagnetic couplings for 1 and 3 and an overall dominant ferromagnetic coupling for 4, which presents metamagnetic behavior with a magnetic phase transition at a critical temperature of 6 K and a transition field of ca. 6030 Oe. The results demonstrate that the EE azido and syn-anti carboxylato bridges in our cases induce an antiferomagnetic interaction, and the anti-anti carboxylato bridge in 4 mediates a ferromagnetic interaction. The magnetic interaction through the EO azido bridge in 3 and 4 has a dependence on the value of the M-N-M bond angle. PMID:19382812

Chen, Zi-Lu; Jiang, Chun-Fang; Yan, Wei-Hong; Liang, Fu-Pei; Batten, Stuart R

2009-06-01

298

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

299

Inversion of one-dimensional scattering data using Prony's method  

SciTech Connect

A one-dimensional configuration is the simplest geometry to invert, yet it has practical application to such problems as scattering from inhomogeneous half spaces and propagation on nonuniform transmision lines. Whether the medium parameters vary continuously or discretely with position, the problem's numerical description can usually be developed in finite-difference approximation. As such, the scattered and transmitted fields can be represented as exponential series, whose exponents are related to the electrical thicknesses of the layers which make up the model. If the exponents or poles are derivable from field data, then the inverse problem is formally solvable. This paper considers application of Prony's method, a procedure for obtaining the poles of exponential signals, to such one-dimensional problems. Analysis of both time-domain and frequency-domain data is studied. The effects of the medium characteristics, number of layers, and other factors are examined. It is concluded that Prony's method has merit for certain classes of one-dimensional inverse problems.

Miller, E.K.; Lager, D.L.

1982-01-01

300

One-dimensional crystal with a complex periodic potential  

SciTech Connect

A one-dimensional crystal model is constructed with a complex periodic potential. A wave function solution for the crystal model is derived without relying on Bloch functions. The new wave function solution of this model is shown to correspond to the solution for the probability amplitude of a two-level system. The energy discriminant is evaluated using an analytic formula derived from the probability amplitude solution, and based on an expansion parameter related to the energy and potential amplitude. From the wave function energy discriminant the crystal band structure is derived and related to standard energy bands and gaps. It is also shown that several of the properties of the two-level system apply to the one-dimensional crystal model. The two-level system solution which evolves in time is shown to manifest as a spatial configuration of the one-dimensional crystal model. The sensitivity of the wave function probability density is interpreted in the context of the new solution. The spatial configuration of the wave function, and the appearance of a long wavelength in the wave function probability density is explained in terms of the properties of Bessel functions.

Boyd, John K.

2001-01-01

301

1D coordination polymers with polychalcogenides as linkers between metal atoms  

NASA Astrophysics Data System (ADS)

The reactions of zinc metal with elemental selenium and selenium/sulfur mixtures in liquid ammonia or methylamine under solvothermal conditions in closed glass ampoules at 50 C lead within some days specifically to [Zn(NH3)2Se4]n (1), [Zn(MeNH2)2Se4]n (2), [Zn(NH3)2Se2.23S1.77]n (3). From MnCl2, Rb2Se and excess Se in n-butylamine [Mn(nBuNH2)4Se6]n (4) is obtained after prolonged reaction time at ambient temperature. The compounds are sensitive towards air and loss of NH3 or the amine ligands. The crystal structures were determined by single crystal diffraction at low temperatures. As a common structural feature, all compounds represent 1D coordination polymers with polychalcogenide chains as linkers between the metal atoms and consist of infinite [M-Chm-]n chains (M=Zn, Mn; Chm=Se4, (S/Se)4, Se6). The Zn central atoms in 1-3 have tetrahedral coordination with two amine ligands, the Mn atoms in 4 have octahedral coordination with four amine ligands and cis position of the two Se atoms. Raman spectra of 1-3 show the stretching mode vibrations of the Ch4 groups. The observation of S-S, S-Se, and Se-Se vibration bands in the spectrum of 3 indicates the presence of mixed S/Se polyanions. An optical band gap of 1.86(5) eV was determined for 2 by diffuse reflectance spectroscopy.

Kysliak, Oleksandr; Beck, Johannes

2013-07-01

302

A soft copper(II) porous coordination polymer with unprecedented aqua bridge and selective adsorption properties.  

PubMed

Herein, the synthesis, crystal structure, and full characterization of a new soft porous coordination polymer (PCP) of ([Cu(2)(dmcapz)(2)(OH(2))]DMF(1.5))(n) (1) formulation, which is easily obtained in the reaction of CuX(2) (X = Cl, NO(3)) salts with 3,5-dimethyl-4-carboxypyrazole (H(2)dmcapz) is present. Compound 1 shows a copper(II) dinuclear secondary building unit (SBU), which is supported by two pyrazolate bridges and an unprecedented H(2)O bridge. The dinuclear SBUs are further bridged by the carboxylate ligands to build a diamondoid porous network. The structural transformations taking place in 1 framework upon guest removal/uptake has been studied in detail. Indeed, the removal of the bridging water molecules gives rise to a metastable evacuated phase (1?b) that transforms into an extremely stable porous material (1?c) after freezing at liquid-nitrogen temperature. The soaking of 1?c into water allows the complete and instantaneous recover of the water-exchanged material (1?a'). Remarkably, 1?b and 1?c materials possess structural bistability, which results in the switchable adsorptive functions. Therefore, the gas-adsorption properties of both materials have been studied by means of single-component gas adsorption isotherms as well as by variable-temperature pulse-gas chromatography. Both materials present permanent porosity and selective gas-adsorption properties towards a variety of gases and vapors of environmental and industrial interest. Moreover, the flexible nature of the coordination network and the presence of highly active convergent open metal sites confer on these materials intriguing gas-adsorption properties with guest-triggered framework-breathing phenomena being observed. The plasticity of Cu(II) metal center and its ability to form stable complexes with different coordination numbers is at the origin of the structural transformations and the selective-adsorption properties of the studied materials. PMID:22933314

Quartapelle Procopio, Elsa; Fukushima, Tomohiro; Barea, Elisa; Navarro, Jorge A R; Horike, Satoshi; Kitagawa, Susumu

2012-08-30

303

Guest responsivity of a two-dimensional coordination polymer incorporating a cholesterol-based co-ligand.  

PubMed

To implement specific guest responsivity, a hydrophobic cholesterol-based co-ligand, cholest-5-en-3-yl-4-isonicotinate (Cholpy), was incorporated into a two-dimensional Hofmann-type Co(ii)Ni(ii) coordination polymer. The chemically programmed structure successfully demonstrated the unique guest response with remarkable chromatic changes. PMID:23877189

Kajitani, Kazuki; Koshiyama, Tomomi; Hori, Akihiro; Ohtani, Ryo; Mishima, Akio; Torikai, Kohei; Ebine, Makoto; Oishi, Tohru; Takata, Masaki; Kitagawa, Susumu; Ohba, Masaaki

2013-07-23

304

Synthesis, Magnetic Susceptibility, and Spectroscopic Properties of Single- and Mixed-Valence Iron Oxalate, Squarate, and Dihydroxybenzoquinone Coordination Polymers.  

National Technical Information Service (NTIS)

Magnetic susceptibility data for several Fe(II) coordination polymers containing oxalate or squarate dianions are reported in the temperature range 4.2-300 K. Low temperature magnetism of Fe(C2O4)(H2O)2 is dominated by intrachain ordering near 32 K follow...

J. T. Wrobleski D. B. Brown

1979-01-01

305

The role of IAEA in coordinating research and transferring technology in radiation chemistry and processing of polymers  

Microsoft Academic Search

The IAEA has been playing a significant role in fostering developments in radiation technology in general and radiation processing of polymers in particular, among its Member States (MS) and facilitate know-how\\/technology transfer to developing MS. The former is usually achieved through coordinated research projects (CRP) and thematic technical meetings, while the latter is mainly accomplished through technical cooperation (TC) projects.

M. Haji-Saeid; M. H. Sampa; N. Ramamoorthy; O. Gven; A. G. Chmielewski

2007-01-01

306

Bringing an "old" biological buffer to coordination chemistry: new 1D and 3D coordination polymers with [Cu(4)(Hbes)(4)] cores for mild hydrocarboxylation of alkanes.  

PubMed

New water-soluble 1D and 3D Cu(II)/Na coordination polymers 1-3 bearing unprecedented [Cu(4)(Hbes)(4)] cores have been easily generated by aqueous-medium self-assembly and fully characterized, thus opening up the use of the common biological buffer H(3)bes, (HO(3)SCH(2)CH(2))N(CH(2)CH(2)OH)(2), in synthetic coordination chemistry. Apart from representing the first isolated and structurally characterized coordination compounds derived from H(3)bes, 1-3 show a remarkable promoting effect in the mild aqueous-medium hydrocarboxylation, by CO and H(2)O, of gaseous alkanes (C(3)H(8) and n-C(4)H(10)) to the corresponding carboxylic acids, which are obtained in up to 95% yields based on the alkane. PMID:20545321

Kirillov, Alexander M; Coelho, Jaime A S; Kirillova, Marina V; da Silva, M Ftima C Guedes; Nesterov, Dmytro S; Gruenwald, Katrin R; Haukka, Matti; Pombeiro, Armando J L

2010-07-19

307

Quantum and Thermal Effects of Dark Solitons in a One-Dimensional Bose Gas  

SciTech Connect

We numerically study the imprinting and dynamics of dark solitons in a bosonic atomic gas in a tightly confined one-dimensional harmonic trap both with and without an optical lattice. Quantum and thermal fluctuations are synthesized within the truncated Wigner approximation in the quasicondensate description. We track the soliton coordinates and calculate position and velocity uncertainties. We find that the phase fluctuations lower the classically predicted soliton speed and seed instabilities. Individual runs show interactions of solitons with sound waves, splitting, and disappearing solitons.

Martin, A. D.; Ruostekoski, J. [School of Mathematics, University of Southampton, Southampton SO17 1BJ (United Kingdom)

2010-05-14

308

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

309

The advantage of reversible coordination polymers in producing visible light sensitized Eu(iii) emissions over EDTA via excluding water from the coordination sphere.  

PubMed

In this paper, we report on the impact of the structure of ligands on the luminescence enhancement of Eu(iii) by directly exciting Eu(iii) with visible light in aqueous media. Upon replacing the water molecules that coordinated around a Eu(3+) ion with a ditopic ligand 1,11-bis(2,6-dicarboxypyridin-4-yloxy)-3,6,9-trioxaundecane (L2EO4) or ethylenediaminetetraacetic acid disodium salt (EDTA), significant luminescence can be obtained. L2EO4 may occupy all 9 coordinating sites of a Eu(3+) ion at proper L2EO4/Eu ratios, whereas EDTA only occupies 6 of them with 3 sites left for water at various EDTA/Eu ratios. These coordinated water molecules quench the fluorescence of EDTA-Eu complexes drastically so that the luminescence is about 30 times lower than that of the L2EO4-Eu system. Furthermore, the negatively charged L2EO4/Eu = 3/2 coordinated complex can be further transformed into coordination 'polymers' by mixing with a positively charged block polyelectrolyte, which forms electrostatic micelles with further enhanced luminescence. The emission of the EDTA-Eu complex is not influenced by the addition of polymers due to the formation of stable small 1?:?1 EDTA-Eu complex which doesn't change with increasing concentration. Our work points out that the L2EO4-Eu system is superior to the EDTA-Eu system in creating visible light sensitized Eu(iii) luminescence, and the emission of Eu(iii) can be indeed significantly enhanced to an applicable level by excluding all the water molecules in the coordination sphere of Eu(iii). PMID:23965918

Xu, Limin; Jing, Yuyang; Feng, Liangzhu; Xian, Zhaoyang; Yan, Yun; Liu, Zhuang; Huang, Jianbin

2013-08-22

310

Synthesis, crystal structures and characterization of four coordination polymers based on 5-amino-2,4,6-triiodoisophthalic acid  

SciTech Connect

One homochiral 1D coordination polymer [Cu(ATIBDC)(2,2'-bipy)].3H{sub 2}O.CH{sub 3}OH (1) and three achiral 1D coordination polymers: [Cd(ATIBDC)(2,2'-bipy)(H{sub 2}O)].3H{sub 2}O (2), [Cd(ATIBDC)(phen)(H{sub 2}O)].4H{sub 2}O (3), and [Mn(ATIBDC)(phen){sub 2}].5H{sub 2}O (4) have been synthesized and characterized (H{sub 2}ATIBDC=5-amino-2,4,6-triiodoisophthalic acid, 2,2'-bipy=2,2'-bipyridine, and phen=1,10-phenanthroline). Extended high dimensional network architectures are further constructed with the help of weak secondary interactions, such as hydrogen bonding, aromatic stacking, and halogen bonding (C-I..{pi} and C-I...N/O). Complex 1 crystallizes in the monoclinic system with chiral space group P2(1) and exhibits a right-handed 2{sub 1} helical chain structure. The homochirality of 1 was confirmed by CD spectrum. Interestingly, two new configurations of decameric water cluster are found in 3 and 4. The acyclic tetrameric cluster (H{sub 2}O){sub 3}(CH{sub 3}OH) in 1 and (H{sub 2}O){sub 4} in 2 array into highly ordered helical infinite chains. Thermal stabilities of all the complexes have been studied. Solid state fluorescent properties of the Cd(II) complexes have been explored. -- Graphical abstract: The synthesis, crystal structures and characterization of one 1D homochiral coordination polymer and three achiral 1D coordination polymers with 5-amino-2,4,6-triiodoisophthalic acid (H{sub 2}ATIBDC) are reported. Display Omitted highlights: > Four 1D coordination polymers with 5-amino-2,4,6-triiodoisophthalate are reported. > The halogen bonds play important roles in the supramolecular assembly. > Solid state fluorescent properties of the Cd(II) complexes are explored.

Zhang Koulin, E-mail: klzhang@yzu.edu.c [Key Laboratory of Environmental Material and Environmental Engineering of Jiangsu Province, College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002 (China); Chang Yan; Zhang Jingbo [Key Laboratory of Environmental Material and Environmental Engineering of Jiangsu Province, College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002 (China); Yuan Limin [Test and Analysis Center, Yangzhou University, Yangzhou 225002 (China); Deng Ye; Diao Guowang [Key Laboratory of Environmental Material and Environmental Engineering of Jiangsu Province, College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002 (China); Ng, Seik Weng [Department of Chemistry, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2011-05-15

311

Assembly of a phospho-molybdic Wells-Dawson-based silver coordination polymer derived from Keggin polyoxoanion cluster.  

PubMed

A 2D Wells-Dawson-based silver(I) coordination polymer was achieved based on silver-Schiff base building blocks and [P(2)Mo(18)O(62)](6-) clusters using AgNO(3), N,N'-bis(furan-2-ylmethylene)hydrazine and Keggin [PMo(12)O(40)](3-) as original materials at room temperature. It is structurally characterized by IR spectroscopy, (31)P NMR, XRPD, thermogravimetric (TG) analyses and X-ray crystallography. The structure of 1 exhibits a novel crystalline 2D coordination polymer constructed by the coordination interaction between the Wells-Dawson polyoxoanion [P(2)Mo(18)O(62)](6-) and Ag-L species. The luminescent property of 1 in the solid state is investigated. PMID:23027404

Dang, Dong-Bin; An, Bing; Bai, Yan; Niu, Jing-Yang

2012-10-02

312

Quantum quench in an atomic one-dimensional Ising chain.  

PubMed

We study nonequilibrium dynamics for an ensemble of tilted one-dimensional atomic Bose-Hubbard chains after a sudden quench to the vicinity of the transition point of the Ising paramagnetic to antiferromagnetic quantum phase transition. The quench results in coherent oscillations for the orientation of effective Ising spins, detected via oscillations in the number of doubly occupied lattice sites. We characterize the quench by varying the system parameters. We report significant modification of the tunneling rate induced by interactions and show clear evidence for collective effects in the oscillatory response. PMID:23952393

Meinert, F; Mark, M J; Kirilov, E; Lauber, K; Weinmann, P; Daley, A J; Ngerl, H-C

2013-07-31

313

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.

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

2013-09-01

314

Efficient thermodynamic description of multicomponent one-dimensional Bose gases  

SciTech Connect

We present a method of obtaining nonlinear integral equations characterizing the thermodynamics of one-dimensional multicomponent gases interacting via a {delta}-function potential. In the case of the repulsive two-component Bose gas we obtain a simple system of two nonlinear integral equations, allowing for an efficient numerical implementation, in contrast with the infinite number of coupled equations obtained by employing the thermodynamic Bethe ansatz. Our technique makes use of the quantum transfer matrix and the fact that, in a certain continuum limit, multicomponent gases can be obtained from appropriate anisotropic spin chains.

Kluemper, Andreas [Fachbereich C Physik, Bergische Universitaet Wuppertal, DE-42097 Wuppertal (Germany); Patu, Ovidiu I. [Fachbereich C Physik, Bergische Universitaet Wuppertal, DE-42097 Wuppertal (Germany); Institute for Space Sciences, Bucharest-Magurele RO-077125 (Romania)

2011-11-15

315

A one-dimensional basic oscillator model of the vircator  

NASA Astrophysics Data System (ADS)

A one-dimensional model of the virtual cathode oscillator (vircator) is proposed keeping only the essential physical processes. The basic model consists of a radiating charge in an oscillating electric field. Using parameters from (realistic) particle-in-cell simulations such as the charge Q and amplitude E1 of the oscillating electric field, the model correctly predicts the amplitude of virtual cathode oscillation and the power radiated. The basic model is then extended to incorporate beam-cavity interaction and the resonance effect.

Biswas, Debabrata

2009-06-01

316

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

317

Fractional calculus in one-dimensional isotropic thermo-viscoelasticity  

NASA Astrophysics Data System (ADS)

A new fractional relaxation operator is derived using the methodology of fractional calculus. The governing coupled fractional differential equations in the frame of the thermo-viscoelasticity with fractional order heat transfer are applied to the one-dimensional problem with heat sources. Laplace transform and state space techniques are used to get the solution. According to the numerical results and its graphs, conclusion about the new theory of thermo-viscoelasticity has been constructed. The theories of coupled thermo-viscoelasticity and of generalized thermo-viscoelasticity with one relaxation time follow as limit cases.

Ezzat, Magdy A.; El-Karamany, Ahmed S.; El-Bary, Alaa A.; Fayik, Mohsen A.

2013-07-01

318

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

319

One-dimensional metal oxide nanostructures for heterogeneous catalysis  

NASA Astrophysics Data System (ADS)

Metal oxides are of paramount importance in heterogeneous catalysis as either supports or active phases. Controlled synthesis of one-dimensional (1D) metal oxide nanostructures has received enormous attention in heterogeneous catalysis due to the possibility of tailoring the properties of metal oxides by tuning their shapes, sizes, and compositions. This feature article highlights recent advances in shape controlled synthesis of 1D metal oxide nanostructures and their applications in heterogeneous catalysis, with the aim of introducing new insights into the heterogeneous catalyst design.

Zhang, Qian; Wang, Hsin-Yi; Jia, Xinli; Liu, Bin; Yang, Yanhui

2013-07-01

320

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

321

Numerical Simulations of One-dimensional Microstructure Dynamics  

SciTech Connect

Results of numerical simulations of one-dimensional wave propagation in microstructured solids are presented and compared with the corresponding results of wave propagation in given layered media. A linear microstructure model based on Mindlin theory is adopted and represented in the framework of the internal variable theory. Fully coupled systems of equations for macro-motion and microstructure evolution are rewritten in the form of conservation laws. A modification of wave propagation algorithm is used for numerical calculations. It is shown how the initial microstructure model can be improved in order to match the results obtained by both approaches.

Berezovski, M.; Berezovski, A.; Engelbrecht, J. [Centre for Nonlinear Studies, Institute of Cybernetics at Tallinn University of Technology, Akadeemia tee 21, 12618 Tallinn (Estonia)

2010-05-21

322

Conductance Distributions in Quasi-One-Dimensional Disordered Wires  

NASA Astrophysics Data System (ADS)

A detailed analysis of the distribution of conductances P(g) of quasi-one-dimensional disordered wires in the metal-insulator crossover is presented. P(g) obtained from a Monte Carlo solution of the Dorokhov, Mello, Pereyra, and Kumar (DMPK) scaling equation is in full agreement with ``tight-binding'' numerical calculations of bulk disordered wires. Perturbation theory is shown to be valid even for mean dimensionless conductances of the order of 1. In the crossover regime <~1, P(g) presents a sharp feature at g=1 which is different from that observed in surface disordered wires.

Froufe-Prez, L. S.; Garca-Mochales, P.; Serena, P. A.; Mello, P. A.; Senz, J. J.

2002-11-01

323

One-Dimensional Rydberg Gas in a Magnetoelectric Trap  

SciTech Connect

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.

Mayle, Michael [Theoretische Chemie, Physikalisch-Chemisches Institut, Universitaet Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany); Hezel, Bernd [Physikalisches Institut, Universitaet Heidelberg, Philosophenweg 12, D-69120 Heidelberg (Germany); Lesanovsky, Igor [Institut fuer Theoretische Physik, Universitaet Innsbruck, A-6020 Innsbruck (Austria); Schmelcher, Peter [Theoretische Chemie, Physikalisch-Chemisches Institut, Universitaet Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany); Physikalisches Institut, Universitaet Heidelberg, Philosophenweg 12, D-69120 Heidelberg (Germany)

2007-09-14

324

Accuracy of differential sensitivity for one-dimensional shock problems  

SciTech Connect

The technique called Differential Sensitivity has been applied to the system of Eulerian continuum mechanics equations solved by a hydrocode. Differential Sensitivity uses forward and adjoint techniques to obtain output response sensitivity to input parameters. Previous papers have described application of the technique to two-dimensional, multi-component problems. Inaccuracies in the adjoint solutions have prompted us to examine our numerical techniques in more detail. Here we examine one-dimensional, one material shock problems. Solution accuracy is assessed by comparison to sensitivities obtained by automatic differentiation and a code-based adjoint differentiation technique. {copyright} {ital 1998 American Institute of Physics.}

Henninger, R.J.; Maudlin, P.J.; Rightley, M.L. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

1998-07-01

325

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

326

Self-healing of fractured one-dimensional brittle nanostructures  

NASA Astrophysics Data System (ADS)

Recent experiments have shown that fractured GaAs nanowires can heal spontaneously inside a transmission electron microscope. Here we perform molecular-dynamics simulations to investigate the atomic mechanism of this self-healing process. As the distance between two fracture surfaces becomes less than 1.0?nm, a strong surface attraction is generated by the electrostatic interaction, which results in Ga-As re-bonding at the fracture site and restoration of the nanowire. The results suggest that self-healing might be prevalent in ultrathin one-dimensional nanostructures under near vacuum conditions.

Wang, J.; Lu, C.; Wang, Q.; Xiao, P.; Ke, F. J.; Bai, Y. L.; Shen, Y. G.; Wang, Y. B.; Liao, X. Z.; Gao, H. J.

2012-04-01

327

The stability of one-dimensional stellar systems  

NASA Astrophysics Data System (ADS)

One-dimensional stellar systems which are described by a distribution function which depends on the system energy are demonstrated to be monotonically decreasing, with the changes in the distribution function with respect to changes in the energy always having a negative value. A necessary condition for the stability is analytically defined, with the second variation of the equilibrium potential formulated by the Poisson equation, with respect to the x-plane, also having a negative value. The condition is obtained by means of the water-bag model of Feix et al. (1971).

Gillon, D.

1982-10-01

328

Noise diagnostics using one-dimensional quantum cellular automata  

NASA Astrophysics Data System (ADS)

We study propagation of correlated errors during quantum simulation due to global pulse errors. Our model system consists of a one dimensional alternating array of two distinct species (or subspaces) of atoms distributed in n lattice sites with a nearest neighbor Ising-type interaction. Time evolution is generated according to a set of quantum cellular automata (QCA) rules which can be implemented through application of global control pulses on either species. We characterize the fidelity for generating entangled states and discuss how to use the system as a sensitive detector of environmental noise. We discuss how to build an architecture suitable for ensemble QCA experiments using a two-dimensional optical lattice.

Kim, Young Soon; Davidson, Matthew; Brennen, Gavin; Williams, Carl

2005-05-01

329

Quantum mechanics of graphene with a one-dimensional potential  

SciTech Connect

Electron states in graphene with a one-dimensional potential have been studied. An approximate solution has been obtained for a small angle between vectors of the incident electron momentum and potential gradient. Exactly solvable problems with a potential of the smoothened step type U(x) Utanh(x/a) and a potential with a singularity U(x) = -U/(|x| + d) are considered. The transmission/reflection coefficients and phases for various potential barriers are determined. A quasi-classical solution is obtained.

Miserev, D. S. [Novosibirsk State University (Russian Federation); Entin, M. V., E-mail: entin@isp.nsc.ru [Russian Academy of Sciences, Institute of Semiconductor Physics, Siberian Branch (Russian Federation)

2012-10-15

330

One-dimensional hybrid nanostructures with light-controlled properties.  

PubMed

One-dimensional organic-inorganic nanostructure has gained extensive attention among photo and photoelectronic applications. Organic and inorganic (metal or semiconductor) nanowires that could, through bottom-up fabrication, as well as template directed synthesis, enable diverse applications in nanoscale electronics and photoelectronics. In comparison, semiconductor organic-inorganic hybrid nanowires have initiated a growing aspect due to their improved photoelectronic and photovoltaic devices as well as light-controlled properties. The motivation of this perspective is to describe the fundamental principles and photonic applications on hybrid nanowires, in which synthesis and light-controlled properties of hybrid organic-inorganic semiconductor nanowires was highlighted. PMID:19672487

Liu, Xiaofeng; Li, Yuliang

2009-04-20

331

Weakly interacting Bose gas in the one-dimensional limit.  

PubMed

We prepare a chemically and thermally one-dimensional (1D) quantum degenerate Bose gas in a single microtrap. We introduce a new interferometric method to distinguish the quasicondensate fraction of the gas from the thermal cloud at finite temperature. We reach temperatures down to kT?0.5??(?) (transverse oscillator eigenfrequency ?(?)) when collisional thermalization slows down as expected in 1D. At the lowest temperatures the transverse-momentum distribution exhibits a residual dependence on the line density n(1D), characteristic for 1D systems. For very low densities the approach to the transverse single-particle ground state is linear in n(1D). PMID:21231675

Krger, P; Hofferberth, S; Mazets, I E; Lesanovsky, I; Schmiedmayer, J

2010-12-28

332

One-dimensional zinc phosphates with linear chain structure  

Microsoft Academic Search

Three one-dimensional zinc phosphates, [C5N2H14][Zn(HPO4)2], I, [C10N4H26][Zn(HPO4)2].2H2O II, and [C4N2H6]2[Zn(HPO4)], III, have been prepared employing hydro\\/solvothermal methods in the presence of organic amines. While I and II consist of linear chains of corner-shared four-membered rings, III is a polymeric wire where the amine molecule is directly bonded to the metal center. The wire, as well as the chain in these

Ayi A Ayi; S. Neeraj; Amitava Choudhury; Srinivasan Natarajan; C. N. R Rao

2001-01-01

333

One-dimensional inverse scattering and spectral problems  

Microsoft Academic Search

Inverse scattering and spectral one-dimensional problems are discussed\\u000asystematically in a self-contained way. Many novel results, due to the author\\u000aare presented. The classical results are often presented in a new way. Several\\u000ahighlights of the new results include:\\u000a Analysis of the invertibility of the steps in the Gel'fand-Levitan and\\u000aMarchenko inversion procedures, Theory of the inverse problem with I-function

Alexander G. Ramm

2003-01-01

334

Adiabatic pumping in the quasi-one-dimensional triangle lattice  

NASA Astrophysics Data System (ADS)

We analyze the properties of the quasi-one-dimensional triangle lattice emphasizing the occurrence of flat bands and band touching via the tuning of the lattice hopping parameters and on-site energies. The spectral properties of the infinite system will be compared with the transmission through a finite piece of the lattice with attached semi-infinite leads. Furthermore, we investigate the adiabatic pumping properties of such a system: Depending on the transmission through the lattice, this results in nonzero integer charge transfers or transfers that increase linearly with the lattice size.

Schulze, Michael; Bercioux, Dario; Urban, Daniel F.

2013-01-01

335

Statistical properties of one-dimensional random lasers.  

PubMed

Statistical properties of a laser based on a one-dimensional disordered superlattice open at one side are studied numerically. The passive normal modes of the system are determined using the Feshbach projection technique. It is found that the mode competition due to the spacial hole burning leads to a saturation of the number of lasing modes with increasing pump rate. It is also responsible for nonmonotonic dependence of intensities of lasing modes as functions of pumping. Computed distributions of spectral spacing and intensity statistics are in qualitative agreement with experimental results. PMID:19257422

Zaitsev, Oleg; Deych, Lev; Shuvayev, Vladimir

2009-01-30

336

One-dimensional model for the fractional quantum Hall effect  

NASA Astrophysics Data System (ADS)

A simple one-dimensional model is proposed, in which N spinless repulsively interacting fermions occupy M>N degenerate states. It is argued that the energy spectrum and the wavefunctions of this system strongly resemble the spectrum and wavefunctions of 2D electrons in the lowest Landau level (the problem of the Fractional Quantum Hall Effect). In particular, Laughlin-type wavefunctions describe ground states at filling factors v = N/M = 1/q, q odd.. Within this model the complimentary wavefunction for v=1?1/q is found explicitly, and extremely simple ground state wavefunctions for arbitrary odd-denominator filling factors are proposed.

Dyakonov, M. I.

2013-08-01

337

One-dimensional quasi-relativistic particle in the box  

Microsoft Academic Search

Two-term Weyl-type asymptotic law for the eigenvalues of one-dimensional quasi-relativistic Hamiltonian (-h^2 c^2 d^2\\/dx^2 + m^2 c^4)^(1\\/2) + V_well(x) (the Klein-Gordon square-root operator with electrostatic potential) with the infinite square well potential V_well(x) is given: the n-th eigenvalue is equal to (n pi\\/2 - pi\\/8) h c\\/a + O(1\\/n), where 2a is the width of the potential well. Simplicity of

Kamil Kaleta; Mateusz Kwasnicki; Jacek Malecki

2011-01-01

338

One-dimensional neutron imager for the Sandia Z facility.  

PubMed

A multiinstitution collaboration is developing a neutron imaging system for the Sandia Z facility. The initial system design is for slit aperture imaging system capable of obtaining a one-dimensional image of a 2.45 MeV source producing 5x10(12) neutrons with a resolution of 320 microm along the axial dimension of the plasma, but the design being developed can be modified for two-dimensional imaging and imaging of DT neutrons with other resolutions. This system will allow us to understand the spatial production of neutrons in the plasmas produced at the Z facility. PMID:19044511

Fittinghoff, David N; Bower, Dan E; Hollaway, James R; Jacoby, Barry A; Weiss, Paul B; Buckles, Robert A; Sammons, Timothy J; McPherson, Leroy A; Ruiz, Carlos L; Chandler, Gordon A; Torres, Jos A; Leeper, Ramon J; Cooper, Gary W; Nelson, Alan J

2008-10-01

339

Devil's staircase in a one-dimensional mapping  

NASA Astrophysics Data System (ADS)

We give a one-dimensional mapping which is a simple example that the periodic orbits show an arithmetic furcation as a function of a parameter characterizing the mapping. The mapping is a piecewise linear function which consists of three parts, that is, a line with slope 1, a line with slope 0 and a line with slope a>1. When the frequency is defined by the ratio of the number of times of visiting the lines with slope a and with slope 0 within a period to the period, the frequency takes on the elements of Farey's set and behaves as a complete devil's staircase as a function of a parameter.

Horiguchi, T.; Morita, T.

1984-07-01

340

Magnetic field induced order in quasi-one-dimensional systems  

NASA Astrophysics Data System (ADS)

We investigate possible ordered phases in a magnetic field in quasi-one-dimensional conductors (Q1D). Long ago [I.E. Dzyaloshinskii, E.I. Kats, JETP 28 (1969) 178] we found that sufficiently strong external magnetic field leads to instability of the Fermi state with an arbitrarily weak repulsion between the particles. In the present communication we generalize this idea and provide more details to assign a physical meaning to such a state. We show that without umklapp processes the found instability corresponds to antiferromagnetic (spin density wave) order, whereas umklapp processes favor to Cooper pairing.

Dzyaloshinskii, I. E.; Kats, E. I.

2012-06-01

341

Numerical analysis for one-dimensional Cauchy singular integral equations  

NASA Astrophysics Data System (ADS)

The paper presents a selection of modern results concerning the numerical analysis of one-dimensional Cauchy singular integral equations, in particular the stability of operator sequences associated with different projection methods. The aim of the paper is to show the main ideas and approaches, such as the concept of transforming the question of the stability of an operator sequence into an invertibility problem in a certain Banach algebra or the concept of certain scales of weighted Besov spaces to prove convergence rates of the sequence of the approximate solutions. Moreover, computational aspects, in particular the construction of fast algorithms, are discussed.

Junghanns, Peter; Silbermann, Bernd

2000-12-01

342

Majorana fermion exchange in quasi-one-dimensional networks  

NASA Astrophysics Data System (ADS)

Heterostructures of spin-orbit coupled materials with s-wave superconductors are thought to be capable of supporting zero-energy Majorana bound states. Such excitations are known to obey non-Abelian statistics in two dimensions, and are thus relevant to topological quantum computation (TQC). In a one-dimensional system, Majorana states are localized to phase boundaries. In order to bypass the constraints of one dimension, a wire network may be created, allowing the exchange of Majoranas by way of junctions in the network. Alicea have proposed such a network as a platform for TQC, showing that the Majorana bound states obey non-Abelian exchange statistics even in quasi-one-dimensional systems. Here we show that the particular realization of non-Abelian statistics produced in a Majorana wire network is highly dependent on the local properties of individual wire junctions. For a simply connected network, the possible realizations can be characterized by the chirality of individual junctions. There is in general no requirement for junction chiralities to remain consistent across a wire network. We show how the chiralities of different junctions may be compared experimentally and discuss the implications for TQC in Majorana wire networks.

Clarke, David J.; Sau, Jay D.; Tewari, Sumanta

2011-07-01

343

Hydrogen peroxide stabilization in one-dimensional flow columns  

NASA Astrophysics Data System (ADS)

Rapid hydrogen peroxide decomposition is the primary limitation of catalyzed H2O2 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

344

Constraint and gauge shocks in one-dimensional numerical relativity  

SciTech Connect

We study how different types of blowups can occur in systems of hyperbolic evolution equations of the type found in general relativity. In particular, we discuss two independent criteria that can be used to determine when such blowups can be expected. One criteria is related to the so-called geometric blowup leading to gradient catastrophes, while the other is based upon the ODE-mechanism leading to blowups within finite time. We show how both mechanisms work in the case of a simple one-dimensional wave equation with a dynamic wave speed and sources, and later explore how those blowups can appear in one-dimensional numerical relativity. In the latter case we recover the well known 'gauge shocks' associated with Bona-Masso-type slicing conditions. However, a crucial result of this study has been the identification of a second family of blowups associated with the way in which the constraints have been used to construct a hyperbolic formulation. We call these blowups 'constraint shocks' and show that they are formulation specific, and that choices can be made to eliminate them or at least make them less severe.

Reimann, Bernd [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A.P. 70-543, Mexico D.F. 04510 (Mexico); Max Planck Institut fuer Gravitationsphysik, Albert Einstein Institut, Am Muehlenberg 1, 14476 Golm (Germany); Alcubierre, Miguel; Nunez, Dario [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A.P. 70-543, Mexico D.F. 04510 (Mexico); Gonzalez, Jose A. [Institute for Gravitational Physics and Geometry, Penn State University, University Park, Pennsylvania 16802 (United States)

2005-03-15

345

Inverse determination of thermal conductivity for one-dimensional problems  

SciTech Connect

Two finite difference procedures are presented for the inverse determination of the thermal conductivity in a one-dimensional heat conduction domain. The thermal conductivity is reconstructed from the inverse analysis based on the assumption that the temperature measurements are either available continuously over the entire domain or at discrete grid points. The convergence and stability of the computational algorithms are investigated. It is concluded that both procedures are first-order accurate methods. A comparison of the exact thermal conductivity with the one estimated was made to confirm the validity of the numerical procedures. The close agreement between the two results confirms that the proposed finite difference techniques are effective procedures for the inverse determination of thermal conductivity in a one-dimensional heat conduction domain. The methods are applicable for linear and nonlinear spatially - as well as temperature-dependent thermal conductivities. Additionally, the special feature of the present techniques is that a priori knowledge of the functional form for the thermal conductivity is not mandatory. 25 refs.

Lam, T.T.; Yeung, W.K. [Aerospace Corp, El Segundo, CA (United States)

1995-04-01

346

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

347

One dimensional global and local solution for ICRF heating  

SciTech Connect

A numerical code GLOSI [Global and Local One-dimensional Solution for Ion cyclotron range of frequencies (ICRF) heating] is developed to solve one-dimensional wave equations resulting from the use of radio frequency (RF) waves to heat plasmas. The code uses a finite difference method. Due to its numerical stability, the code can be used to find both global and local solutions when imposed with appropriate boundary conditions. Three types of boundary conditions are introduced to describe wave scattering, antenna wave excitation, and fixed tangential wave magnetic field. The scattering boundary conditions are especially useful for local solutions. The antenna wave excitation boundary conditions can be used to excite fast and slow waves in a plasma. The tangential magnetic field boundary conditions are used to calculate impedance matrices, which describe plasma and antenna coupling and can be used by an antenna code to calculate antenna loading. These three types of boundary conditions can also be combined to describe various physical situations in RF plasma heating. The code also includes plasma thermal effects and calculates collisionless power absorption and kinetic energy flux. The plasma current density is approximated by a second-order Larmor radius expansion, which results in a sixth-order ordinary differential equation.

Wang, C.Y.; Batchelor, D.B.; Jaeger, E.F.; Carter, M.D.

1995-02-01

348

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

2011-06-07

349

Generating arbitrary one-dimensional dose profiles using rotational therapy  

NASA Astrophysics Data System (ADS)

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.

Zhuang, Tingliang; Wu, Qiuwen

2010-10-01

350

Relationship between channel and sorption properties in coordination polymers with interdigitated structures.  

PubMed

Porous coordination polymers constructed from Zn(2+) and isophthalate with linear bipyridyl-type ligands were synthesized. [Zn(ip)(bpb)](n) (CID-21; ip=isophthalate, bpb=1,4-bis(4-pyridyl)benzene), [Zn(ip)(bpt)](n) (CID-22; bpt=3,6-bis(4-pyridyl)-1,2,4,5-tetrazine), and [Zn(ip)(bpa)](n) (CID-23; bpa=1,4-bis(4-pyridyl)acetylene) all have interdigitated structures of layers and similar void volumes (?27%). In these compounds, 1D bottleneck-type channels run along the perpendicular direction of the layer stacking and their properties are strongly dominated by the dipyridyl linker ligands. Because of the difference in packing of 2D layers, CID-21 and CID-22 have relatively rigid porous structures, whereas CID-23 has greater flexibility, as indicated by the results of powder X-ray diffraction studies. The micropores of CID-22 surrounded by tetrazine moieties adsorb polar molecules, such as methanol and water. The higher affinity of CID-22 for water than CID-21 is supported by a theoretical study. The 1D channel of CID-23 is wider than that of the other two compounds, which enables the incorporation of aromatic molecules. This is because the shape of the bpa linker ligand generates a wider pore diameter (8.6 ). Only CID-23 can adsorb a benzene molecule and the isotherm of benzene has a gate-opening-type profile. This offers proof of the guest accommodation process through large structural transformation from a nonporous to a porous structure. The flexibility and restricted pore space of CID-23, at 298 K, allows only benzene, but not cyclohexane, to enter the channels. The porous structure exhibits clear selectivity for these similar guests. The incorporation of an elongated dipyridyl linker ligand in the 2D coordination layers provides a strategy for the design of microporous compounds with different flexibilities, microporous environments, and separation abilities. PMID:21433150

Hijikata, Yuh; Horike, Satoshi; Sugimoto, Masayuki; Sato, Hiroshi; Matsuda, Ryotaro; Kitagawa, Susumu

2011-03-23

351

Construction of a series of coordination polymers from three imidazole-based multi-carboxylate ligands.  

PubMed

2-Carboxylphenyl, 3-carboxylphenyl and 4-carboxylphenyl groups were introduced into the 2-position of imidazole-4,5-dicarboxylate system, respectively, obtaining three multi-functional ligands 2-(2-carboxylphenyl)-1H-imidazole-4,5-dicarboxylic acid (o-CPhH4IDC), 2-(3-carboxylphenyl)-1H-imidazole-4,5-dicarboxylic acid (m-CPhH4IDC) and 2-(4-carboxylphenyl)-1H-imidazole-4,5-dicarboxylic acid (p-CPhH4IDC). Then the three organic ligands are employed to react with Sr(ii) and Cd(ii) ions. Subsequently, five 3D or 2D polymers, [Sr(o-CPhH2IDC)]n (), [Sr3(m-CPhHIDC)2(H2O)3]n (), [Sr(p-CPhH2IDC)(H2O)]n (), [Cd(o-CPhH2IDC)(H2O)2]n () and {[Cd3(m-CPhHIDC)2(H2O)8]2H2O}n (), have been hydro(solvo)thermally synthesized and structurally characterized. Compound is a (5,5)-connected 3D structure with unique "H-shape" channels. Three kinds of coordination environments around the Sr atoms are exhibited in compound . Both compounds and contain unusual irregular cages. Compound displays a (4,6)-connected 3D porous framework composed of right-handed helices connected by p-CPhH2IDC(2-) anions. Both compounds and present net-like layer structures. These various architectures demonstrate the versatile coordination abilities of the three imidazole-based multi-carboxylate ligands. PMID:23945991

Guo, Beibei; Li, Li; Wang, Yang; Zhu, Yanyan; Li, Gang

2013-09-18

352

A series of Zn-4f heterometallic coordination polymers and a zinc complex containing a flexible mixed donor dicarboxylate ligand.  

PubMed

A new zinc compound, together with a corresponding series of Zn-4f heterometallic coordination polymers, namely, [Zn(H2PBDA)(PBDA)]n (1), {[Ln2(PBDA)22H2O] [Zn2(PBDA)2Cl2]}n [H2PBDA = 3-(pyridin-3-yl-oxy) benzene-1,2-dicarboxylic acid, and Ln = Pr(2), Nd(3), Eu(4), Gd(5), Dy(6), Ho(7), Er(8)] have been hydrothermally synthesized and characterized systematically. Polymers 2-8 feature two-dimensional (2D) 4,4 networks, containing the original 1D heterometallic double stranded chains composed of [Ln2Zn2(PBDA)2] entities. The extensive hydrogen bonding and ?-? stacking interactions were observed to stabilize the extended architectures. The luminescence emission spectra of the polymers vary depending on the lanthanide(III) ion present. Informative magnetic susceptibility measurements show that the same carboxylate bridging fashion of the PBDA ligand results in the different magnetic properties occurring within the heterometallic coordination polymers. In addition, polymer 6 exhibits an interesting slow magnetic relaxation behavior at lower temperatures. PMID:23549773

Feng, Xun; Feng, Yu-Quan; Liu, Lang; Wang, Li-Ya; Song, Hong-Liang; Ng, Seik-Weng

2013-06-01

353

One-dimensional assembly of silica nanospheres: effects of nonionic block copolymers.  

PubMed

The effects of polymers on the one-dimensional assembly of silica nanospheres (SNSs) in the liquid phase are systematically investigated using nonionic poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (abbreviated as PEO-PPO-PEO) triblock copolymers with varying hydrophilic-lipophilic balance (HLB) values. Scanning electron microscopy is employed for morphological observations of the polymer-mediated assemblies of SNSs on the basis of which the optimal pH for 1D assembly (pH(1D)) is determined. To clarify the polymers' effects on the 1D assembly of SNSs, the relationships between pH(1D) and polymers' HLB values, the numbers of hydrophilic EO and hydrophobic PO units, and the relative ratio of N(PO)/N(EO) are examined. Zeta potential measurements are conducted to investigate the electrostatic repulsion among the SNSs in the presence of block copolymers. It is found that the relative hydrophilicity of the block copolymers greatly affects the balance of interactions in the 1D assembly of SNSs. Block copolymers with large HLB values promote the 1D assembly of SNSs under near-neutral pH conditions, whereas the block copolymers with small HLB values promote 1D assembly under basic pH conditions. Therefore, the 1D assembly of SNSs is achieved over an extensive pH range (7.5-9.5) through the employment of block copolymers of different hydrophilic and hydrophobic block lengths. PMID:22934598

Zhou, Shujun; Sakamoto, Takeshi; Wang, Junzheng; Sugawara-Narutaki, Ayae; Shimojima, Atsushi; Okubo, Tatsuya

2012-09-07

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; Grnker, Ronny; Baburin, Igor A; Senkovska, Irena; Mueller, Uwe; Kaskel, Stefan

2012-01-31

355

An unusual 3D coordination polymer based on bridging interactions of the nucleobase adenine.  

PubMed

The first 3D coordination polymer containing a nucleobase as a bridging ligand, [[Cu2(mu-ade)4(H2O)2][Cu(ox)(H2O)]2 x approximately 14H2O]n (1), has been synthesized by reaction of adenine (Hade) with a basic solution of K2[Cu(ox)2] x 2H2O (ox = oxalato dianion). Compound 1 crystallizes in the trigonal space group R3 with a = b = 31.350(1) angstroms, c = 14.285(1) angstroms, V = 12158.7(10) angstroms3, and Z = 9. X-ray analysis shows a covalent 3D network in which the copper(II) centers are bridged by tridentate mu-N3,N7,N9 adeninate ligands. The compound has relatively large, nanometer-sized tubes associated with the self-assembly process directed solely by metal-ligand interactions. The covalent 3D framework remains intact upon removal of the guest water molecules trapped in the nanotubes. Magnetic measurements indicate an overall antiferromagnetic behavior of the compound. PMID:15257577

Garca-Tern, Juan P; Castillo, Oscar; Luque, Antonio; Garca-Couceiro, Urko; Romn, Pascual; Lezama, Luis

2004-07-26

356

Synthesis and characterization of the mixed ligand coordination polymer CPO-5  

NASA Astrophysics Data System (ADS)

The synthesis and crystal structures of a novel coordination polymer and its high-temperature variant are described. The as-synthesized material (CPO-5-as), of composition Zn(4,4'-bipyridine)(4,4'-biphenyldicarboxylate).3H2O, crystallizes in the triclinic space group P-1 (No. 2) with a=11.0197(2), b=14.2975(3), c=7.6586(1), ?=95.9760(9), ?=108.026(1), ?=91.373(1) and V=1139.16(4)3. CPO-5-as is composed of tetrahedral zinc centers that are connected by the organic linkers to give five independent, interpenetrating diamond networks. In the structure, there is additional space for channels that are filled with three water molecules. These water molecules can be removed, leading to an anhydrous variant at 130oC. CPO-5-130, of composition Zn(4,4'-bipyridine)(4,4'-biphenyldicarboxylate), crystallizes in the triclinic space group P-1 (No. 2) with a=11.1844(6), b=14.0497(7), c=7.7198(3), ?=96.917(2), ?=109.527(2), ?=89.115(3) and V=1134.6(1)3. The structure of the five interpenetrating networks is virtually unchanged after the dehydration resulting in CPO-5-130 being a porous structure with an estimated free volume of 19.8%.

Kongshaug, Kjell Ove; Fjellvg, Helmer

2003-11-01

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

Effect of humidity on the performance of microporous coordination polymers as adsorbents for CO2 capture.  

PubMed

The CO(2)-capture performance of microporous coordination polymers of the M/DOBDC series (where M = Zn, Ni, Co, and Mg; DOBDC = 2,5-dioxidobenzene-1,4-dicarboxylate) was evaluated under flow-through conditions with dry surrogate flue gas (5/1 N(2)/CO(2)). The CO(2) capacities were found to track with static CO(2) sorption capacities at room temperature, with Mg/DOBDC demonstrating an exceptional capacity for CO(2) (23.6 wt %). The effect of humidity on the performance of Mg/DOBDC was investigated by collecting N(2)/CO(2)/H(2)O breakthrough curves at relative humidities (RHs) in the feed of 9, 36, and 70%. After exposure at 70% RH and subsequent thermal regeneration, only about 16% of the initial CO(2) capacity of Mg/DOBDC was recovered. However, in the case of Ni/DOBDC and Co/DOBDC, approximately 60 and 85%, respectively, of the initial capacities were recovered after the same treatment. These data indicate that although Mg/DOBDC has the highest capacity for CO(2), under the conditions used in this study, Co/DOBDC may be a more desirable material for deployment in CO(2) capture systems because of the added costs associated with flue gas dehumidification. PMID:21488612

Kizzie, Austin C; Wong-Foy, Antek G; Matzger, Adam J

2011-04-13

359

Syntheses, structures, and properties of multidimensional lithium coordination polymers based on aliphatic carboxylic acids.  

PubMed

Three lithium coordination polymers, [Li4(H2O)2(EDTA)] (1), [Li4(H2O)4(BTCA)] (2), and (H2NMe2)2[Li2(H2O)2(BTCA)] (3) (H4EDTA = ethylenediaminetetraacetic acid, H4BTCA = 1,2,3,4-butane tetracarboxylic acid, H2NMe2 = dimethyl amine), have been synthesized by reacting lithium salts with aliphatic carboxylic acids using a solvothermal method. The structures of all the three complexes have been determined by single crystal X-ray diffraction studies. The single crystal structure analysis revealed that complex 1 has a three-dimensional framework, whereas complex 2 has 2D sheets and complex 3 has 1D chains. In addition, these lithium complexes contain various inorganic motifs with a tetramer in 1 and 2, and discrete tetrahedra in 3 and have further been connected through organic ligands to construct multidimensional structures. Further, the electrochemical properties of complexes 13 have been studied to evaluate these compounds as electrode materials for lithium ion batteries with discharge capacities of around 100 mA h g(-1) in the first thirty cycles. PMID:23235699

Cheng, Pei-Chi; Lin, Wei-Cheng; Tseng, Feng-Shuen; Kao, Ching-Che; Chang, Ting-Guang; Senthil Raja, Duraisamy; Liu, Wei-Ren; Lin, Chia-Her

2013-02-28

360

Porous coordination polymers as novel sorption materials for heat transformation processes.  

PubMed

Porous coordination polymers (PCPs)/metal-organic frameworks (MOFs) are inorganic-organic hybrid materials with a permanent three-dimensional porous metal-ligand network. PCPs or MOFs are inorganic-organic analogs of zeolites in terms of porosity and reversible guest exchange properties. Microporous water-stable PCPs with high water uptake capacity are gaining attention for low temperature heat transformation applications in thermally driven adsorption chillers (TDCs) or adsorption heat pumps (AHPs). TDCs or AHPs are an alternative to traditional air conditioners or heat pumps operating on electricity or fossil fuels. By using solar or waste heat as the operating energy TDCs or AHPs can significantly help to minimize primary energy consumption and greenhouse gas emissions generated by industrial or domestic heating and cooling processes. TDCs and AHPs are based on the evaporation and consecutive adsorption of coolant liquids, preferably water, under specific conditions. The process is driven and controlled by the microporosity and hydrophilicity of the employed sorption material. Here we summarize the current investigations, developments and possibilities of PCPs/MOFs for use in low-temperature heat transformation applications as alternative materials for the traditional inorganic porous substances like silica gel, aluminophosphates or zeolites. PMID:23945102

Janiak, Christoph; Henninger, Stefan K

2013-01-01

361

Hydrothermal Synthesis, Crystal Structure and Electrochemical Behavior of 2d Hybrid Coordination Polymer  

NASA Astrophysics Data System (ADS)

A novel metal-organic coordination polymer [Cu(phen)(L)0.5(H2O)]n (H4L = (N,N?-5,5?-bis(isophthalic acid)-p-xylylenediamine, and phen = 1,10-phenanthroline) has been hydrothermally synthesized and characterized by elemental analysis, IR, TGA, and single-crystal X-ray diffraction. The crystallographic data show that the title compound crystallizes in monoclinic space group P21/n with a = 10.682(2), b = 15.682(3), c = 11.909(2) , ? = 91.39(3), V = 1994.3(7) 3, C24H17CuN3O5, Mr = 490.95, Dc = 1.635 g/cm3, F(000) = 1004, Z = 4, ?(MoK?) = 1.141 mm-1, the final R = 0.0418 and wR = 0.0983 for 3578 observed reflections (I > 2?(I)). The structural analyses reveal that the title compound exhibits shows a 2D layer structure, which are further linked by hydrogen bonding interactions to form a three-dimensional supramolecular network. In addition, the thermal stability and electrochemical behavior of title compound has been studied. CCDC: 900413.

Fan, Weiqiang; Zhu, Lin; Shi, Weidong; Chen, Fuxiao; Bai, Hongye; Song, Shuyan; Yan, Yongsheng

2013-06-01

362

Photophysical studies of europium coordination polymers based on a tetracarboxylate ligand.  

PubMed

Reaction of europium sulfate octahydrate with p-terphenyl-3,3?,5,5?-tetracarboxylic acid (H4ptptc) in a mixed solvent system has afforded three new coordination polymers formulated as {[Eu(ptptc)0.75(H2O)2]0.5DMF1.5H2O}n (1), {[Me2H2N]2 [Eu2(ptptc)2(H2O)(DMF)]1.5DMF7H2O}n (2), and {[Eu(Hptptc)(H2O)4]0.5DMFH2O}n (3). Complex 1 exhibits a three-dimensional (3D) metal-organic framework based on {Eu2(?2-COO)2(COO)4}n chains, complex 2 shows a 3D metal-organic framework constructed by [Eu2(?2-COO)2(COO)6](2-) dimetallic subunits, and complex 3 features a 2D layer architecture assembling to 3D framework through ?? interactions. All complexes exhibit the characteristic red luminescence of Eu(III) ion. The triplet state of ligand H4ptptc matches well with the emission level of Eu(III) ion, which allows the preparation of new optical materials with enhanced luminescence properties. The luminescence properties of these complexes are further studied in terms of their emission quantum yields, emission lifetimes, and the radiative/nonradiative rates. PMID:23773050

Gai, Yan-Li; Jiang, Fei-Long; Chen, Lian; Bu, Yang; Su, Kong-Zhao; Al-Thabaiti, Shaeel A; Hong, Mao-Chun

2013-06-17

363

Two-step approach to one-dimensional anharmonic oscillators  

SciTech Connect

We propose a two-step approach to one-dimensional anharmonic oscillators. A generalized coherent-state ansatz is introduced for the first step. A theorem of Wick's ordering and a Bogoliubov transformation are used to simplify the derivation. This is shown to be equivalent to the Hartree approximation. In the second step, standard diagonalization is used for the transformed Hamiltonian. The method yields a clear physical picture and is capable of producing accurately all the low-lying energy levels in a single diagonalization. Asymptotic expansions for the energy levels are easily obtained. The connection with a pure quartic oscillator is pointed out and as a by-product no calculation is necessary in that model. We also include cubic couplings and apply the method successfully for the two-well oscillator.

Hsue, C.; Chern, J.L.

1984-02-15

364

Exact semiclassical expansions for one-dimensional quantum oscillators  

SciTech Connect

A set of rules is given for dealing with WKB expansions in the one-dimensional analytic case, whereby such expansions are not considered as approximations but as exact encodings of wave functions, thus allowing for analytic continuation with respect to whichever parameters the potential function depends on, with an exact control of small exponential effects. These rules, which include also the case when there are double turning points, are illustrated on various examples, and applied to the study of bound state or resonance spectra. In the case of simple oscillators, it is thus shown that the Rayleigh{endash}Schr{umlt o}dinger series is Borel resummable, yielding the exact energy levels. In the case of the symmetrical anharmonic oscillator, one gets a simple and rigorous justification of the Zinn-Justin quantization condition, and of its solution in terms of {open_quotes}multi-instanton expansions.{close_quotes} {copyright} {ital 1997 American Institute of Physics.}

Delabaere, E. [UMR CNRS J. A. Dieudonne No. 6621, University of Nice, 06108 Nice Cedex 2 (France); Dillinger, H.; Pham, F. [University of Nice, Department of Maths, UMR CNRS J.A. Dieudonne No. 6621, 06108 Nice Cedex 2 (France)

1997-12-01

365

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

366

Efficient algorithm for approximating one-dimensional ground states  

NASA Astrophysics Data System (ADS)

The density-matrix renormalization-group method is very effective at finding ground states of one-dimensional (1D) quantum systems in practice, but it is a heuristic method, and there is no known proof for when it works. In this article we describe an efficient classical algorithm which provably finds a good approximation of the ground state of 1D systems under well-defined conditions. More precisely, our algorithm finds a matrix product state of bond dimension D whose energy approximates the minimal energy such states can achieve. The running time is exponential in D, and so the algorithm can be considered tractable even for D, which is logarithmic in the size of the chain. The result also implies trivially that the ground state of any local commuting Hamiltonian in 1D can be approximated efficiently; we improve this to an exact algorithm.

Aharonov, Dorit; Arad, Itai; Irani, Sandy

2010-07-01

367

One-dimensional planar hydrodynamic theory of shock ignition  

SciTech Connect

A one-dimensional planar compressible-piston-like model is used to investigate the basic physics behind shock-ignition inertial confinement fusion implosions. We discuss the theoretical limit set by rarefaction waves on the maximum hot-spot pressure achievable through conventional compression. Three ignitor shock techniques are presented to mitigate the effects of rarefaction waves, enhance the stagnation hot-spot pressure, and improve the ignition conditions. Elimination of rarefaction waves can lead to an {approx}80% increase in peak implosion pressures, while implosions augmented with ignitor shocks are shown to increase the peak pressures by a factor of {approx}4. These techniques are then discussed and the optimal energy ratio between the initial shell kinetic energy and the ignitor pulse energy is given.

Nora, R.; Betti, R. [Fusion Science Center and Laboratory for Laser Energetics, Physics and Astronomy, University of Rochester, Rochester, New York 14623 (United States)

2011-08-15

368

Wigner quantization of some one-dimensional Hamiltonians  

NASA Astrophysics Data System (ADS)

Recently, several papers have been dedicated to the Wigner quantization of different Hamiltonians. In these examples, many interesting mathematical and physical properties have been shown. Among those we have the ubiquitous relation with Lie superalgebras and their representations. In this paper, we study two one-dimensional Hamiltonians for which the Wigner quantization is related with the orthosymplectic Lie superalgebra osp(1|2). One of them, the Hamiltonian ?=x?p?, is popular due to its connection with the Riemann zeros, discovered by Berry and Keating on the one hand and Connes on the other. The Hamiltonian of the free particle, ?f=p?2/2, is the second Hamiltonian we will examine. Wigner quantization introduces an extra representation parameter for both of these Hamiltonians. Canonical quantization is recovered by restricting to a specific representation of the Lie superalgebra osp(1|2).

Regniers, G.; van der Jeugt, J.

2010-12-01

369

Scale dependent partitioning of one-dimensional aperiodic set diffraction  

NASA Astrophysics Data System (ADS)

We give a multiresolution partition of pure point parts of diffraction patterns of one-dimensional aperiodic sets. When an aperiodic set is related to the Golden Ratio, denoted by tau, it is well known that the pure point part of its diffractive measure is supported by the extension ring of tau, denoted by mathbb{Z}[tau]. The partition we give is based on the formalism of the so called tau-integers, denoted by mathbb{Z}_tau. The set of tau-integers is a selfsimilar set obeying mathbb{Z}_tau/tau^{j-1}subsetmathbb{Z}_tau/tau^j subset mathbb{Z}_tau/tau^{j + 1} subsetmathbb{Z}[tau], jinmathbb{Z}. The pure point spectrum is then partitioned with respect to this Russian doll like sequence of subsets mathbb{Z}_tau/tau^j. Thus we deduce the partition of the pure point part of the diffractive measure of aperiodic sets.

Elkharrat, A.

2004-06-01

370

Entangling Qubits in a One-Dimensional Harmonic Oscillator  

NASA Astrophysics Data System (ADS)

We present a method for generating entanglement between qubits associated with a pair of particles interacting in a one-dimensional harmonic potential. By considering the effect of the interaction on the energy spectrum of the system, we show that, under certain approximations, a ``power-of-SWAP" operation is performed on the initial two-qubit quantum state without requiring any time-dependent control. Initialization errors and deviations from our approximation are shown to have a negligible effect on the final state. Using a GPU-accelerated iteration scheme to find numerical solutions to the two-particle time-dependent Schr"odinger equation, we demonstrate that it is possible to generate maximally entangled Bell states between the two qubits with high fidelity for a range of possible interaction potentials.

Owen, Edmund; Dean, Matthew; Barnes, Crispin

2012-02-01

371

One-dimensional planar hydrodynamic theory of shock ignition  

NASA Astrophysics Data System (ADS)

A one-dimensional planar compressible-piston-like model is used to investigate the basic physics behind shock-ignition inertial confinement fusion implosions. We discuss the theoretical limit set by rarefaction waves on the maximum hot-spot pressure achievable through conventional compression. Three ignitor shock techniques are presented to mitigate the effects of rarefaction waves, enhance the stagnation hot-spot pressure, and improve the ignition conditions. Elimination of rarefaction waves can lead to an ~80% increase in peak implosion pressures, while implosions augmented with ignitor shocks are shown to increase the peak pressures by a factor of ~4. These techniques are then discussed and the optimal energy ratio between the initial shell kinetic energy and the ignitor pulse energy is given.

Nora, R.; Betti, R.

2011-08-01

372

Luminescent one-dimensional nanostructures of perylene bisimides.  

PubMed

Perylene bisimides form a unique class of organic semiconductors, in this investigation two symmetrical perylene bisimides caped with 1-butyl (B-PTCDI) and 4,4-diethoxybutyl (DB-PTCDI) have been synthesized and characterized. The compounds self-assembled as a network of nanobelts and nanorods in the solution based self-assembly process. Morphologies of these self-assembled structures were characterized by optical, fluorescence, scanning and transmission electronic microscopic techniques. One-dimensional self-assemblies of B-PTCDI and DB-PTCDI molecules are due to the strong ?-? stacking ability of perylene core and assistance given by the side chains and solvent. Observed molecular self-assembly and electronic properties of the molecules. The observed self-assembly was supported by molecular modeling studies using density functional theory. PMID:23743040

Boobalan, G; Imran, P K M; Nagarajan, S

2013-05-15

373

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

374

Negative refraction in one-dimensional photonic crystals  

NASA Astrophysics Data System (ADS)

Photonic crystals are artificial structures that have periodic dielectric components with different refractive indices. Under certain conditions, they abnormally refract the light, a phenomenon called negative refraction. Here, we discuss recent theoretical and simulation results that showed that negative refraction could be present near the low frequency edge of at least the second, fourth and sixth bandgaps of a lossless one-dimensional photonic crystals (1DPC) structure. That is, negative refraction is a multiband phenomenon. We also discuss the negative refraction correctness condition that gives the angular region where negative refraction occurs. We compare two current negative refraction theoretical models with recent experimental results. In order to succeed, an output refraction correction is utilized. The correction uses Snell's law and an effective refractive index based on two effective dielectric constants. We found good agreement between experiment and both theoretical models in the negative refraction zone.

Lugo, J. E.; Doti, Rafael; Faubert, J.

375

One-dimensional three-body problem via symbolic dynamics.  

PubMed

Symbolic dynamics is applied to the one-dimensional three-body problem with equal masses. The sequence of binary collisions along an orbit is expressed as a symbol sequence of two symbols. Based on the time reversibility of the problem and numerical data, inadmissible (i.e., unrealizable) sequences of collisions are systematically found. A graph for the transitions among various regions in the Poincare section is constructed. This graph is used to find an infinite number of periodic sequences, which implies an infinity of periodic orbits other than those accompanying a simple periodic orbit called the Schubart orbit. Finally, under reasonable assumptions on inadmissible sequences, we prove that the set of admissible symbol sequences forms a Cantor set. (c) 2000 American Institute of Physics. PMID:12779414

Tanikawa, Kiyotaka; Mikkola, Seppo

2000-09-01

376

Loschmidt echo in one-dimensional interacting Bose gases  

SciTech Connect

We explore Loschmidt echo in two regimes of one-dimensional interacting Bose gases: the strongly interacting Tonks-Girardeau (TG) regime, and the weakly interacting mean-field regime. We find that the Loschmidt echo of a TG gas decays as a Gaussian when small (random and time independent) perturbations are added to the Hamiltonian. The exponent is proportional to the number of particles and the magnitude of a small perturbation squared. In the mean-field regime the Loschmidt echo shows richer behavior: it decays faster for larger nonlinearity, and the decay becomes more abrupt as the nonlinearity increases; it can be very sensitive to the particular realization of the noise potential, especially for relatively small nonlinearities.

Lelas, K.; Seva, T.; Buljan, H. [Faculty of Electrical Engineering Mechanical Engineering and Naval Architecture, University of Split, Rudjera Boskovica BB, 21000 Split (Croatia); Department of Physics, University of Zagreb, Bijenicka c. 32, 10000 Zagreb (Croatia)

2011-12-15

377

Quantum criticality of a one-dimensional attractive Fermi gas  

SciTech Connect

We obtain an analytical equation of state for one-dimensional strongly attractive Fermi gases for all parameter regimes in current experiments. From the equation of state, we derive universal scaling functions that control whole thermodynamical properties in quantum critical regimes and illustrate the physical origin of quantum criticality. It turns out that the critical properties of the system are described by those of free fermions and those of mixtures of fermions with masses m and 2m. We also show how these critical properties of bulk systems can be revealed from the density profile of trapped Fermi gases at finite temperatures and can be used to determine the T=0 phase boundaries without any arbitrariness.

Guan Xiwen; Ho, Tin-Lun [Department of Theoretical Physics, Research School of Physics and Engineering, Australian National University, Canberra, ACT 0200 (Australia); Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States)

2011-08-15

378

Weakly Interacting Bose Gas in the One-Dimensional Limit  

SciTech Connect

We prepare a chemically and thermally one-dimensional (1D) quantum degenerate Bose gas in a single microtrap. We introduce a new interferometric method to distinguish the quasicondensate fraction of the gas from the thermal cloud at finite temperature. We reach temperatures down to kT{approx_equal}0.5({h_bar}/2{pi}){omega}{sub perpendicular} (transverse oscillator eigenfrequency {omega}{sub perpendicular}) when collisional thermalization slows down as expected in 1D. At the lowest temperatures the transverse-momentum distribution exhibits a residual dependence on the line density n{sub 1D}, characteristic for 1D systems. For very low densities the approach to the transverse single-particle ground state is linear in n{sub 1D}.

Krueger, P.; Lesanovsky, I. [Midlands Ultracold Atom Research Centre (MUARC), School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Hofferberth, S. [Harvard-MIT Center for Ultracold Atoms, Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States); Mazets, I. E. [Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, 1020 Vienna (Austria); Ioffe Physico-Technical Institute, 194021 St. Petersburg (Russian Federation); Schmiedmayer, J. [Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, 1020 Vienna (Austria)

2010-12-31

379

Entanglement dynamics in one-dimensional quantum cellular automata  

SciTech Connect

Several proposed schemes for the physical realization of a quantum computer consist of qubits arranged in a cellular array. In the quantum circuit model of quantum computation, an often complex series of two-qubit gate operations is required between arbitrarily distant pairs of lattice qubits. An alternative model of quantum computation based on quantum cellular automata (QCA) requires only homogeneous local interactions that can be implemented in parallel. This would be a huge simplification in an actual experiment. We find some minimal physical requirements for the construction of unitary QCA in a one-dimensional Ising spin chain and demonstrate optimal pulse sequences for information transport and entanglement distribution. We also introduce the theory of nonunitary QCA and show by example that nonunitary rules can generate environment assisted entanglement.

Brennen, Gavin K.; Williams, Jamie E. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8423 (United States)

2003-10-01

380

Correlation lengths of the repulsive one-dimensional Bose gas  

NASA Astrophysics Data System (ADS)

We investigate the large-distance asymptotic behavior of the static density-density and field-field correlation functions in the one-dimensional Bose gas at finite temperature. The asymptotic expansions of the Bose gas correlators are obtained performing a specific continuum limit in the similar low-temperature expansions of the longitudinal and transversal correlation functions of the XXZ spin chain. In the lattice system the correlation lengths are computed as ratios of the largest and next-largest eigenvalues of the XXZ spin chain quantum transfer matrix. In both cases, lattice and continuum, the correlation lengths are expressed in terms of solutions of Yang-Yang type [C. N. Yang and C. P. Yang, J. Math. Phys.JMAPAQ0022-248810.1063/1.1664947 10, 1151 (1969)] nonlinear integral equations which are easily implementable numerically.

P?u, Ovidiu I.; Klmper, Andreas

2013-09-01

381

Dipolar gases in coupled one-dimensional lattices.  

PubMed

We consider dipolar bosons in two tubes of one-dimensional lattices, where the dipoles are aligned to be maximally repulsive and the particle filling fraction is the same in each tube. In the classical limit of zero intersite hopping, the particles arrange themselves into an ordered crystal for any rational filling fraction, forming a complete devil's staircase like in the single tube case. Turning on hopping within each tube then gives rise to a competition between the crystalline Mott phases and a liquid of defects or solitons. However, for the two-tube case, we find that solitons from 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. PMID:23004615

Bauer, Marianne; Parish, Meera M

2012-06-18

382

Charge Order Fluctuations in one-dimensional silicides  

SciTech Connect

Metallic nanowires are of great interest as interconnects in future nanoelectronic circuits. They also represent important systems for understanding the complexity of electronic interactions and conductivity in one-dimension. We have fabricated exceptionally long and uniform YSi2 nanowires via self-assembly of yttrium atoms on Si(001). The thinnest wires represent one of the closest realizations of the isolated Peierls chain, exhibiting van-Hove type singularities in the one- dimensional density of states and charge order fluctuations below 150 K. The structure of the wire was determined though a detailed comparison of scanning tunneling microscopy data and first-principles calculations. Sporadic broadenings of the wires' cross section imply the existence of a novel metal-semiconductor junction whose electronic properties are governed by the finite- size- and temperature-scaling of the charge ordering correlation.

Zeng, C. [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Kent, Paul R [ORNL; Kim, Tae Hwan [ORNL; Li, An-Ping [ORNL; Weitering, Harm H [ORNL

2008-01-01

383

Efficient algorithm for approximating one-dimensional ground states  

SciTech Connect

The density-matrix renormalization-group method is very effective at finding ground states of one-dimensional (1D) quantum systems in practice, but it is a heuristic method, and there is no known proof for when it works. In this article we describe an efficient classical algorithm which provably finds a good approximation of the ground state of 1D systems under well-defined conditions. More precisely, our algorithm finds a matrix product state of bond dimension D whose energy approximates the minimal energy such states can achieve. The running time is exponential in D, and so the algorithm can be considered tractable even for D, which is logarithmic in the size of the chain. The result also implies trivially that the ground state of any local commuting Hamiltonian in 1D can be approximated efficiently; we improve this to an exact algorithm.

Aharonov, Dorit; Arad, Itai; Irani, Sandy [School of Computer Science and Engineering, Hebrew University, Jerusalem (Israel); School of Computer Science, Tel-Aviv University, Tel-Aviv (Israel); Computer Science Department, University of California, Irvine, California (United States)

2010-07-15

384

Bandgap characteristics of one-dimensional plasma photonic crystal  

NASA Astrophysics Data System (ADS)

When two pump laser pulses intersect in an underdense plasma, plasma Bragg grating (PBG) is induced by the slow-varying ponderomotive force [Z. M. Sheng et al., Appl. Phys. B: Lasers Opt. 77, 673 (2003)]. Such a PBG can be considered as a one-dimensional (1D) plasma photonic crystal (PPC). Here the bandgap characteristic of 1D PPC composed of plasma layers of different densities is investigated theoretically and numerically. It is found that when the maximum density is lower than the critical density of the pump laser, there is only one normal-incidence bandgap. When the maximum density is higher than the critical density of the pump laser, high-order bandgaps are found. The theoretical results are verified by 1D particle-in-cell simulations.

Yin, Yan; Xu, Han; Yu, M. Y.; Ma, Yan-Yun; Zhuo, Hong-Bin; Tian, Cheng-Lin; Shao, Fu-Qiu

2009-10-01

385

Capillary condensation in one-dimensional irregular confinement.  

PubMed

A lattice-gas model with heterogeneity is developed for the description of fluid condensation in finite sized one-dimensional pores of arbitrary shape. Mapping to the random-field Ising model allows an exact solution of the model to be obtained at zero-temperature, reproducing the experimentally observed dependence of the amount of fluid adsorbed in the pore on external pressure. It is demonstrated that the disorder controls the sorption for long pores and can result in H2-type hysteresis. Finite-temperature Metropolis dynamics simulations support analytical findings in the limit of low temperatures. The proposed framework is viewed as a fundamental building block of the theory of capillary condensation necessary for reliable structural analysis of complex porous media from adsorption-desorption data. PMID:23944446

Handford, Thomas P; Prez-Reche, Francisco J; Taraskin, Sergei N

2013-07-30

386

Dynamic correlation functions in one-dimensional quasicondensates  

SciTech Connect

We calculate the static and dynamic single-particle correlation functions in one-dimensional (1D) trapped Bose gases and discuss experimental measurements that can directly probe such correlation functions. Using a quantized hydrodynamic theory for the low-energy excitations, we calculate both the static and dynamic single-particle correlation functions for a 1D Bose gas that is a phase-fluctuating quasicondensate. For the static (equal-time) correlation function, our approximations and results are equivalent to those of Petrov, Shlyapnikov, and Walraven. The Fourier transform of the static single-particle correlation function gives the momentum distribution, which can be measured using Doppler-sensitive Bragg scattering experiments on a highly elongated Bose gas. We show how a two-photon Raman out-coupling experiment can measure the characteristic features of the dynamic or time-dependent single-particle correlation function of a 1D Bose quasicondensate.

Luxat, D.L.; Griffin, A. [Department of Physics, University of Toronto, Toronto, Ontario, M5S 1A7 (Canada)

2003-04-01

387

Fractionalization of itinerant anyons in one-dimensional chains.  

PubMed

We construct models of interacting itinerant non-Abelian anyons moving along one-dimensional chains, focusing, in particular, on itinerant Ising anyon chains, and 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 (non-Abelian) anyonic degrees of freedom--a generalization of spin-charge separation of electrons which occurs in Luttinger liquids. A detailed description of the excitation spectrum by combining spectra for charge and anyonic sectors requires 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. PMID:23003180

Poilblanc, Didier; Troyer, Matthias; Ardonne, Eddy; Bonderson, Parsa

2012-05-14

388

Design optimization of one-dimensional photonic crystal waveguide  

NASA Astrophysics Data System (ADS)

The proposed one-dimensional photonic crystal waveguide structure can be optimized in three steps as outlined below. At first the imaginary part of the Bloch wavevector inside the 1D PC can be made maximum so that the evanescent light field decays most rapidly and thus the confinement factor of a guided mode becomes maximized when the waveguide is completed. This condition uniquely defines the thickness of two layers in 1D PC. Secondly, the omnidirectional mirror condition can be further enforced for the 1D PC to achieve complete inhibition of light escape in the vertical direction. This can be done by ensuring that for a given frequency the point, (?, ?n0/c), on TM lightline falls in the forbidden bandgap. Lastly, the thickness of the centerguiding layer can be uniquely determined for given frequency and propagation constant, considering structural symmetry and phase matching condition between lights outgoing from and incoming to the guiding layer.

I, Jae-Soong; Park, Yeonsang; Jeon, Heonsu

2003-07-01

389

One dimensional simulations of transients in heavy ion injectors  

SciTech Connect

A fast-running time-dependent one-dimensional particle code has been developed to simulate transients in both electrostatic quadrupole and electrostatic column heavy-ion injectors. Two-dimensional effects are incorporated through the use of an approximation to the transverse part of the Laplacian operator. Longitudinal electric fields are solved on a mesh. An external circuit is coupled to the column, and the effect of the beam on the circuit is modeled. Transients such as initial current spikes, space-charge de-bunching, and beam loading of the circuit, are simulated. Future directions for the code include introduction of envelope and centroid equations to provide beam radius and displacement information and the modeling of secondary electron currents arising from beam-spill.

Barnard, J.J.; Caporaso, G.J. [Lawrence Livermore National Lab., CA (US); Yu, S.S.; Eylon, E. [Lawrence Berkeley Lab., CA (US)

1993-05-11

390

ETBFCT: a solver for one-dimensional transport equations  

SciTech Connect

A robust numerical technique for solving a wide class of one-dimensional transport-dominated problems is presented. The method is a finite-difference technique called flux-corrected transport (FCT) that preserves stability without sacrificing accuracy by exploiting the property of positivity. The specific algorithm, ETBFCT, developed by Boris at the Naval Research Laboratory, has been vectorized for execution on the Cray Computer. A single call to ETBFCT solving a transport equation on a 100 node mesh typically takes less than 0.001 cpu second on the Cray. ETBFCT has been modularized to be used as a library routine. The methodology and theory of FCT is discussed, enabling the potential user to make an informed judgment as to the usefulness of the method. The routines comprising the FCT algorithm and the mechanics for their use are then described. Finally, two example transport problems are solved to illustrate the use of ETBFCT. Fortran listings of the algorithm are included.

Gross, R.J.; Baer, M.R.

1985-10-01

391

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

392

Wigner quantization of some one-dimensional Hamiltonians  

SciTech Connect

Recently, several papers have been dedicated to the Wigner quantization of different Hamiltonians. In these examples, many interesting mathematical and physical properties have been shown. Among those we have the ubiquitous relation with Lie superalgebras and their representations. In this paper, we study two one-dimensional Hamiltonians for which the Wigner quantization is related with the orthosymplectic Lie superalgebra osp(1|2). One of them, the Hamiltonian H=xp, is popular due to its connection with the Riemann zeros, discovered by Berry and Keating on the one hand and Connes on the other. The Hamiltonian of the free particle, H{sub f}=p{sup 2}/2, is the second Hamiltonian we will examine. Wigner quantization introduces an extra representation parameter for both of these Hamiltonians. Canonical quantization is recovered by restricting to a specific representation of the Lie superalgebra osp(1|2).

Regniers, G.; Van der Jeugt, J. [Department of Applied Mathematics and Computer Science, Ghent University, Krijgslaan 281-S9, B-9000 Gent (Belgium)

2010-12-15

393

Diffusive radiation in one-dimensional Langmuir turbulence.  

PubMed

We calculate spectra of radiation produced by a relativistic particle in the presence of one-dimensional Langmuir turbulence which might be generated by a streaming instability in the plasma, in particular, in the shock front or at the shock-shock interactions. The shape of the radiation spectra is shown to depend sensitively on the angle between the particle velocity and electric field direction. The radiation spectrum in the case of exactly transverse particle motion is degenerate and similar to that of spatially uniform Langmuir oscillations. In the case of oblique propagation, the spectrum is more complex, it consists of a number of power-law regions and may contain a distinct high-frequency spectral peak. The emission process considered is relevant to various laboratory plasma settings and for astrophysical objects as gamma-ray bursts and collimated jets. PMID:17677604

Fleishman, G D; Toptygin, I N

2007-07-10

394

Slow-light transmission in one-dimensional periodic structures  

SciTech Connect

We have analyzed the transmission properties of pulses through one-dimensional periodic structures in order to systematically explore the best conditions to achieve the maximum delay with the minimum possible distortion. In the absence of absorption and no layer variation, the transmission coefficient t{sub N} can be well approximated by a sum of Lorentzian resonances. The ratio between their width {Gamma}{sub r} and their separation {Delta}{omega}{sub r} is a crucial parameter to characterize the distortion of the transmitted pulse. For typical values of the parameters used in telecommunications and high index of refraction contrasts n{sub 2}/n{sub 1}, the distortion of the transmitted pulse is unacceptably large for frequencies near the edge of the transmission window. We estimate fractional delays achievables in terms of the central frequency used and the pulse bandwidth.

Barco, O. del; Ortuno, M. [Departamento de Fisica-CIOyN, Universidad de Murcia (Spain)

2010-02-15

395

A Reduced Order, One Dimensional Model of Joint Response  

SciTech Connect

As a joint is loaded, the tangent stiffness of the joint reduces due to slip at interfaces. This stiffness reduction continues until the direction of the applied load is reversed or the total interface slips. Total interface slippage in joints is called macro-slip. For joints not undergoing macro-slip, when load reversal occurs the tangent stiffness immediately rebounds to its maximum value. This occurs due to stiction effects at the interface. Thus, for periodic loads, a softening and rebound hardening cycle is produced which defines a hysteretic, energy absorbing trajectory. For many jointed sub-structures, this hysteretic trajectory can be approximated using simple polynomial representations. This allows for complex joint substructures to be represented using simple non-linear models. In this paper a simple one dimensional model is discussed.

DOHNER,JEFFREY L.

2000-11-06

396

One-dimensional photonic crystals as selective back reflectors  

NASA Astrophysics Data System (ADS)

Using the solgel technology and dip-coating method involving the deposition of silica layers and titania layers, we have fabricated symmetrical structures with one-dimensional photonic crystals on both sides of glass substrates. For the structure with five bilayers (SiO2/TiO2) we have obtained the maximum reflectance of 0.967 for the wavelength ?r=493nm and full width at half maximum of the main reflectance peak of FWHM=185nm. The fabricated structures have been analyzed theoretically with the application of the transfer matrix 22 method, allowing for complex refraction indexes for the component layers. The paper presents the applied theoretical model and the discussion involving the calculated and experimental results. Good agreement between the calculation and experimental results has been obtained. The elaborated photonic structures can be applied in solar light concentrators for photovoltaic systems.

Gondek, Ewa; Karasi?ski, Pawe?

2013-06-01

397

One-dimensional ballistic transport with FLAPW Wannier functions  

NASA Astrophysics Data System (ADS)

We present an implementation of the ballistic Landauer-Bttiker transport scheme in one-dimensional systems based on density functional theory calculations within the full-potential linearized augmented plane-wave (FLAPW) method. In order to calculate the conductance within the Green's function method, we map the electronic structure from the extended states of the FLAPW calculation to Wannier functions, which constitute a minimal localized basis set. Our approach benefits from the high accuracy of the underlying FLAPW calculations, allowing us to address the complex interplay of structure, magnetism, and spin-orbit coupling and is ideally suited to study spin-dependent electronic transport in one-dimensional magnetic nanostructures. To illustrate our approach, we study ballistic electron transport in nonmagnetic Pt monowires with a single stretched bond including spin-orbit coupling, and in ferromagnetic Co monowires with different collinear magnetic alignment of the electrodes with the purpose of analyzing the magnetoresistance when going from tunneling to the contact regime. We further investigate spin-orbit scattering due to an impurity atom. We consider two configurations: a Co atom in a Pt monowire and vice versa. In both cases, the spin-orbit induced band mixing leads to a change of the conductance upon switching the magnetization direction from along the chain axis to perpendicular to it. The main contribution stems from ballistic spin scattering for the magnetic Co impurity in the nonmagnetic Pt monowire, and for the Pt scatterer in the magnetic Co monowire from the band formed from states with dxy and dx2-y2 orbital symmetry. We quantify this effect by calculating the ballistic anisotropic magnetoresistance, which displays values up to as much as 7% for ballistic spin scattering and gigantic values of around 100% for the Pt impurity in the Co wire. In addition, we show that the presence of a scatterer can reduce as well as increase the ballistic anisotropic magnetoresistance.

Hardrat, Bjrn; Wang, Neng-Ping; Freimuth, Frank; Mokrousov, Yuriy; Heinze, Stefan

2012-06-01

398

A novel mixed ligand coordination polymer of copper(II): Synthesis, characterisation and magneto-structural correlation  

Microsoft Academic Search

A novel 1D coordination chain polymer {[Cu2(pydc)2(1,10-phen)(H2O)2]3H2O}n (pydc=pyridine-2,3-dicarboxylate, 1,10-phen=1,10-phenantroline) has been synthesised and characterised by elemental analysis, FT-IR spectrum, thermal analysis and variable temperature magnetic susceptibility studies. Single crystal X-ray diffraction measurement of the complex shows two Cu(II) centres are in distorted square pyramidal geometry. The complex shows very interesting hydrogen bonding modes involving the lattice and coordinated water molecules

Shyamapada Shit; Joy Chakraborty; Soma Sen; Guillaume Pilet; Cdric Desplanches; Samiran Mitra

2008-01-01

399

Synthesis, crystal structure, and properties of a double-helical zinc(II) coordination polymer with Ozagrel drug.  

PubMed

By the reaction of Zn(OAc)(2)2H(2)O with Ozagrel, (E)-3-(4-((1H-imidazol-1-yl)methyl)phenyl)acrylic acid (Himpaa), a novel coordination polymer [Zn(impaa)(2)](n)(1) was synthesized and was characterized by IR, elemental analysis, single-crystal X-ray diffraction analysis, photoluminescence spectroscopy, and thermogravimetric and differential thermal analysis. The four-coordinate Zn(II) ions are linked into 1D double-helical chain by the deprotonated impaa(-), which is extended into a 3D supramolecular structure through intermolecular C-HO hydrogen bonds. PMID:22078079

Yang, Wei-Chun; Zheng, Zhe-Bo; Sun, Hao-Ling; Wang, Ke-Zhi

2011-10-20

400

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

401

Tube-type coordination polymers: two- and four-silver(I)-mediated linear networking of calix[4]arene tetracarboxylates.  

PubMed

Two calix[4]arene tetracarboxylates, [calix[4]arene tetraacetate (K(4)CTA) and calix[4]arene tetrabenzoate (K(4)CTB)] as their potassium salts, have been prepared. Employing these as precursors, two Ag(I) coordination polymers incorporating calix[4]arene units have been successfully prepared and their X-ray crystal structures have been determined. In these, the CTA and CTB derivatives are linearly bound to two and four silver atoms, respectively, to generate unusual tubular nanostructures. A comparative NMR study was undertaken to investigate the nature of the metal ion blocking of the tube as observed in the CTA-derived structure. The thermal properties for both coordination polymers were also examined. PMID:22017628

Park, Ki-Min; Lee, Eunji; Park, Chul Soon; Lee, Shim Sung

2011-10-21

402

Novel synthetic approach to creating PtCo alloy nanoparticles by reduction of metal coordination nano-polymers.  

PubMed

PtCo alloy nanoparticles with different metal elemental ratios (Pt/Co = 0.9, 1.6, 2.9, and 3.6) were prepared by a novel synthetic approach, using the transformation reaction of platinum(IV)/cobalt tetracyanoplatinate metal coordination nano-polymers (Pt(II)-CN-Pt(IV)/Co)via a H2 gas-phase reduction. PMID:16193136

Yamada, Mami; Maesaka, Masayuki; Kurihara, Masato; Sakamoto, Masatomi; Miyake, Mikio

2005-09-07

403

Syntheses and Crystal Structures of Cobalt(II) and Nickel(II) Coordination Polymers with 3-Aminobenzoic Acid Ligand  

Microsoft Academic Search

Two coordination polymers, (ML2)n (M = Co (1), Ni (2), L = 3-aminobenzoic acid anion), were synthesized by hydrothermal reaction, and their crystal structures were determined by X-ray diffraction analysis. Both compounds crystallize in monoclinic, space group P21\\/n with a = 8.8029(8), b = 4.5297(4), c = 15.2002(14) , ? = 105.6280(10), C14H12CoN2O4, Mr = 331.19, Z = 2, V

WEI You-Huan; TAN An-Zhi; CHEN Zi-Lu; LIANG Fu-Pei; HU Rui-Xiang

404

In situ generation of functionality in a reactive haloalkane-based ligand for the design of new porous coordination polymers.  

PubMed

Herein, we report new porous coordination polymers (PCPs) via a facile synthetic approach called "in situ generation of functionality in the ligand". Upon a synthetic process of PCPs, a neutral (-CH2OH) or a cationic functionality (-CH2-[4,4'-bipyridine](+)) was generated on a isophthalate ligand from a reactive haloalkane (-CH2Br) moiety, affording two new PCPs. The PCPs have two-dimensional layered structures with large potential solvent-accessible voids for CO2 adsorption. PMID:24016100

Kanoo, Prakash; Matsuda, Ryotaro; Sato, Hiroshi; Li, Liangchun; Jeon, Hyung Joon; Kitagawa, Susumu

2013-09-09

405

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

406

Series of mixed uranyl-lanthanide (Ce, Nd) organic coordination polymers with aromatic polycarboxylates linkers.  

PubMed

Three series of mixed uranyl-lanthanide (Ce or Nd) carboxylate coordination polymers have been successfully synthesized by means of a hydrothermal route using either conventional or microwave heating methods. These compounds have been prepared from mixtures of uranyl nitrate, lanthanide nitrate together with phthalic acid (1,2), pyromellitic acid (3,4), or mellitic acid (5,6) in aqueous solution. The X-ray diffraction (XRD) single-crystal revealed that the phthalate complex (UO(2))(4)O(2)Ln(H(2)O)(7)(1,2-bdc)(4)NH(4)xH(2)O (Ln = Ce(1), Nd(2); x = 1 for 1, x = 0 for 2), is based on the connection of tetranuclear uranyl-centered building blocks linked to discrete monomeric units LnO(2)(H(2)O)(7) via the organic species to generate infinite chains, intercalated by free ammonium cations. The pyromellitate phase (UO(2))(3)Ln(2)(H(2)O)(12)(btec)(3)5H(2)O (Ce(3), Nd(4)) contains layers of monomeric uranyl-centered hexagonal and pentagonal bipyramids linked via the carboxylate arms of the organic molecules. The three-dimensionality of the structure is ensured by the connection of remaining free carboxylate groups with isolated monomeric units LnO(2)(H(2)O)(7). The network of the third series (UO(2))(2)(OH)Ln(H(2)O)(7)(mel)5H(2)O (Ce(5), Nd(6)) is built up from dinuclear uranyl units forming layers through connection with the mellitate ligands, which are further linked to each other through discrete monomers LnO(3)(H(2)O)(6). The thermal decomposition of the various coordination complexes led to the formation of mixed uranium-lanthanide oxide, with the fluorite-type structure at 1500 C (for 1, 2) or 1400 C for 3-6. Expected U/Ln ratio from the crystal structures were observed for compounds 1-6. PMID:22931214

Mihalcea, Ionut; Volkringer, Christophe; Henry, Natacha; Loiseau, Thierry

2012-08-29

407

Synthesis, characterization and photoluminescence properties of two new europium(III) coordination polymers with 3D open framework  

NASA Astrophysics Data System (ADS)

The 3D open framework coordination polymers, [Eu2(fum)3(H2O)4]n3nH2O (1, fum=fumaric acid) and [Eu(pdc)(Hpdc)]n (2, pdc=pyridine-2,5-dicarboxylic acid) have been synthesized via hydrothermal procedure. Their molecular structures were determined by single-crystal X-ray diffraction analysis. Polymer 1 adopts a 3D microporous structure filled with disordered free water molecules which interact by hydrogen bonds with terminal water bound to the metal centers. IR spectroscopy, TGA and powder X-ray diffraction analysis revealed that the remarkable dehydration rehydration process of open-framework 1 is completely reversible. Polymer 2 forms a 3D framework composed of 2D grid-like inorganic subnetworks and pdc ligands as linkers. This solid is highly stable up to 405 C. The solid-state photoluminescence measurements exhibited red light-emitting characteristic of two europium(III) coordination polymers. Moreover, the anhydrous products were found to be more strongly fluorescent and be of longer lifetime.

Zhang, Guoqi; Wang, Qian; Qian, Yan; Yang, Guoqiang; Shi Ma, Jin

2006-08-01

408

Synthesis of nanostructured materials by using metal-cyanide coordination polymers and their lithium storage properties.  

PubMed

Herein, we demonstrate a novel and simple two-step process for preparing LiCoO2 nanocrystals by using a Prussian blue analogue Co3[Co(CN)6]2 as a precursor. The resultant LiCoO2 nanoparticles possess single crystalline nature and good uniformity with an average size of ca. 360 nm. The unique nanostructure of LiCoO2 provides relatively shorter Li(+) diffusion pathways, thus facilitating the fast kinetics of electrochemical reactions. As a consequence, high reversible capacity, excellent cycling stability and rate capability are achieved with these nanocrystals as cathodes for lithium storage. The LiCoO2 nanocrystals deliver specific capacities of 154.5, 135.8, 119, and 100.3 mA h g(-1) at 0.2, 0.4, 1, and 2 C rates, respectively. Even at a high current density of 4 C, a reversible capacity of 87 mA h g(-1) could be maintained. Importantly, a capacity retention of 83.4% after 100 cycles is achieved at a constant discharge rate of 1 C. Furthermore, owing to facile control of the morphology and size of Prussian blue analogues by varying process parameters, as well as the tailored design of multi-component metal-cyanide hybrid coordination polymers, with which we have successfully prepared porous Fe2O3@NixCo3-xO4 nanocubes, one of the potential anode materials for lithium-ion batteries, such a simple and scalable approach could also be applied to the synthesis of other nanomaterials for energy storage devices. PMID:24071706

Nie, Ping; Shen, Laifa; Luo, Haifeng; Li, Hongsen; Xu, Guiyin; Zhang, Xiaogang

2013-09-26

409

The role of IAEA in coordinating research and transferring technology in radiation chemistry and processing of polymers  

NASA Astrophysics Data System (ADS)

The IAEA has been playing a significant role in fostering developments in radiation technology in general and radiation processing of polymers in particular, among its Member States (MS) and facilitate know-how/technology transfer to developing MS. The former is usually achieved through coordinated research projects (CRP) and thematic technical meetings, while the latter is mainly accomplished through technical cooperation (TC) projects. Coordinated research projects encourage research on, and development and practical application of, radiation technology to foster exchange of scientific and technical information. The technical cooperation (TC) programme helps Member States to realize their development priorities through the application of appropriate radiation technology. The IAEA has implemented several coordinated research projects (CRP) recently, including one on-going project, in the field of radiation processing of polymeric materials. The CRPs facilitated the acquisition and dissemination of know-how and technology for controlling of degradation effects in radiation processing of polymers, radiation synthesis of stimuli-responsive membranes, hydrogels and absorbents for separation purposes and the use of radiation processing to prepare biomaterials for applications in medicine. The IAEA extends cooperation to well-known international conferences dealing with radiation technology to facilitate participation of talented scientists from developing MS and building collaborations. The IAEA published technical documents, covering the findings of thematic technical meetings (TM) and coordinated research projects have been an important source of valuable practical information.

Haji-Saeid, M.; Sampa, M. H.; Ramamoorthy, N.; Gven, O.; Chmielewski, A. G.

2007-12-01

410

Validation and Comparison of One-Dimensional Graound Motion Methodologies  

SciTech Connect

Both point- and finite-source stochastic one-dimensional ground motion models, coupled to vertically propagating equivalent-linear shear-wave site response models are validated using an extensive set of strong motion data as part of the Yucca Mountain Project. The validation and comparison exercises are presented entirely in terms of 5% damped pseudo absolute response spectra. The study consists of a quantitative analyses involving modeling nineteen well-recorded earthquakes, M 5.6 to 7.4 at over 600 sites. The sites range in distance from about 1 to about 200 km in the western US (460 km for central-eastern US). In general, this validation demonstrates that the stochastic point- and finite-source models produce accurate predictions of strong ground motions over the range of 0 to 100 km and for magnitudes M 5.0 to 7.4. The stochastic finite-source model appears to be broadband, producing near zero bias from about 0.3 Hz (low frequency limit of the analyses) to the high frequency limit of the data (100 and 25 Hz for response and Fourier amplitude spectra, respectively).

B. Darragh; W. Silva; N. Gregor

2006-06-28

411

Excited states of quasi-one-dimensional hexagonal quantum antiferromagnets  

NASA Astrophysics Data System (ADS)

We investigate the excited states of the quasi-one-dimensional quantum antiferromagnets on hexagonal lattices, including the longitudinal modes based on the magnon-density waves. A model Hamiltonian with a uniaxial single-ion anisotropy is first studied by a spin wave theory based on the one-boson method; the ground state thus obtained is employed for the study of the longitudinal modes. The full energy spectra of both the transverse modes (i.e., magnons) and the longitudinal modes are obtained as functions of the nearest-neighbor coupling and the anisotropy constants. We have found two longitudinal modes due to the noncollinear nature of the triangular antiferromagnetic order, similar to that of the phenomenological field theory approach by Affleck. The excitation energy gaps due to the anisotropy and the energy gaps of the longitudinal modes without anisotropy are then investigated. We then compare our results for the longitudinal energy gaps at the magnetic wave vectors with the experimental results for several antiferromagnetic compounds with both integer and noninteger spin quantum numbers, and we find good agreement after the higher-order contributions are included in our calculations.

Merdan, M.; Xian, Y.

2013-05-01

412

One-dimensional dynamics of nano-scale oxidation  

NASA Astrophysics Data System (ADS)

A continuum model is proposed to describe the process of scanned probe oxidation in the presence of a thin water layer on the surface of a substrate. The model describes the electric field and ion transport in both the liquid and the oxide layers and incorporates the reaction mechanism at the substrate/oxide interface. Further, the influence of the space charge due to ions trapped near the substrate/oxide interface is taken into account. Separation of time scales for the chemical reactions and ion transport as well as the asymptotic limit in terms of a small aspect ratio of the oxide layer are used to reduce the complex system of partial differential equations to a one-dimensional system of ordinary differential equations. The analytical solution of the reduced system results in the evolution equation for the oxide thickness. Numerical simulations of the evolution equation predict features of oxide growth that qualitatively agree with the experimental observations. A parametric study is conducted to determine the influence of the key operating and material parameters on the thickness of the oxide, the electric field, and ion concentration in the system.

Orians, A.; Clemons, C. B.; Golovaty, D.; Young, G. W.

2006-08-01

413

Biosensing with one-dimensional photonic bandgap structure  

NASA Astrophysics Data System (ADS)

The optical properties of photonic bandgap (PBG) structures are highly sensitive to the geometry and refractive index. This makes PBG structures a good host for sensor applications. The binding of target species inside the PBG structure changes the refractive index of the material, which can be detected by monitoring the optical response of the device. One-dimensional PBG biosensors based on porous silicon (PSi) have been fabricated. The device is a microcavity, made of a symmetry breaking PSi layer (defect layer) inserted between two PSi Bragg mirrors. Narrow resonances are introduced in the photoluminescence and reflectance spectra. The large internal surface of the sensor is functionalized for the capture of target biological materials. When the sensor is exposed to the target, binding to the internal surface increases the effective optical thickness of the microcavity and thus causes a red shift of the optical spectrum. The sensor's sensitivity is determined by the morphology and geometry of the device. We will present the details of the materials science, sensor fabrication and optimization, and also describe experiments performed with biological targets.

Ouyang, Huimin; DeLouise, Lisa A.; Christophersen, Marc; Miller, Benjamin L.; Fauchet, Philippe M.

2004-10-01

414

One-dimensional kinetic model for the RIGEL code  

SciTech Connect

In the advanced PIUS design, certain transients such as the ingress of boron-free water into the core are characterized by a shifting axial power shape. Therefore, to be able to simulate such transients more accurately, a one-dimensional kinetic core model has been added to RIGEL, which is the main plant transient analysis tool for PIUS, thus replacing the original point-kinetic representation. In RIGEL, a direct approach is undertaken whereby the core axial nodes are treated similarly to the adjacent fluid nodes with average nodal flux defined at the cell centers, in analogy to pressure, for instance, and the neutron current defined at the coupling junctions, in analogy to fluid flow. A full flux representation is used. The jacobian approach and the direct analogy in treating both neutronic and thermal-hydraulic state variables allow the axial core model to fit rather easily and efficiently into the RIGEL numerics with no need for the separation approximation implied in the quasi-static method. Since the RIGEL solution is based on an efficient sparse matrix algorithm, the improved accuracy does not come at a significant additional computational cost.

Methanani, M. (ABB Atom, Vaesteras (Sweden))

1992-01-01

415

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

416

Bosonization of strongly interacting one-dimensional electrons.  

SciTech Connect

Strong repulsive interactions in a one-dimensional electron system suppress the exchange coupling J of electron spins to a value much smaller than the Fermi energy E{sub F}. The conventional theoretical description of such systems based on the bosonization approach and the concept of Tomonaga-Luttinger liquid is applicable only at energies below J. In this paper, we develop a theoretical approach valid at all energies below the Fermi energy, including a broad range of energies between J and E{sub F}. The method involves bosonization of the charge degrees of freedom, while the spin excitations are treated exactly. We use this technique to calculate the spectral functions of strongly interacting electron systems at energies in the range J << {var_epsilon} << E{sub F}. We show that in addition to the expected features at the wave vector k near the Fermi point k{sub F}, the spectral function has a strong peak centered at k=0. Our theory also provides analytical description of the spectral function singularities near 3k{sub f} (the 'shadow band' features).

Matveev, K. A.; Furusaki, A.; Glazman, L. I.; Materials Science Division; RIKEN; Univ. Minnesota

2007-10-01

417

Critical behavior of a one-dimensional diffusive epidemic process  

SciTech Connect

We investigate the critical behavior of a one-dimensional diffusive epidemic propagation process by means of a Monte Carlo procedure. In the model, healthy (A) and sick (B) individuals diffuse on a lattice with diffusion constants D{sub A} and D{sub B}, respectively. According to a Wilson renormalization calculation, the system presents a second-order phase transition between a steady reactive state and a vacuum state, with distinct universality classes for the cases D{sub A}=D{sub B} and D{sub A}{lt}D{sub B}. A first-order transition has been conjectured for D{sub A}{gt}D{sub B}. In this work we perform a finite size scaling analysis of order parameter data at the vicinity of the critical point in dimension d=1. Our results show no signature of a first-order transition in the case of D{sub A}{gt}D{sub B}. A finite size scaling typical of second-order phase transitions fits well the data from all three regimes. We found that the correlation exponent {nu}=2 as predicted by field-theoretical arguments. Estimates for {beta}/{nu} are given for all relevant regimes.

Fulco, U. L.; Messias, D. N.; Lyra, M. L.

2001-06-01

418

Dynamics in the one-dimensional extended ionic Hubbard model.  

PubMed

We investigate single-particle spectral densities and dynamical charge and spin structure factors of the one-dimensional extended ionic Hubbard model in the band insulator regime by using the perturbative continuous unitary transformations method. The one-body staggered potential is considered as the unperturbed part and the hopping term, on-site electron-electron interaction, and the nearest-neighbor repulsive interaction are treated as the perturbations. The excitation spectrum of this model was determined in a previous work (Hafez and Jafari 2010 Eur. Phys. J. B 78 323). It was shown that when the intersite interaction is off, there are two antibound state modes and one bound state mode in the singlet channel and two bound state modes in the triplet channel, while for finite values of intersite interaction two bound state modes were found in each channel. Our results for dynamical charge and spin structure factors indicate that only one of two bound/antibound state modes can be probed by electron-energy-loss spectroscopy and inelastic neutron scattering experiments. PMID:21628789

Hafez, Mohsen; Abolhassani, M R

2011-06-01

419

One-dimensional extended Hubbard model in the atomic limit.  

PubMed

We present the exact solution of the one-dimensional extended Hubbard model in the atomic limit within the Green's function and equations of motion formalism. We provide a comprehensive and systematic analysis of the model by considering all the relevant response and correlation functions as well as thermodynamic quantities in the whole parameters space. At zero temperature we identify four phases in the plane (U,n) ( U is the on-site potential and n is the filling) and relative phase transitions as well as different types of charge ordering. These features are endorsed by investigating at T=0 the chemical potential and pertinent local correlators, the particle and double occupancy correlation functions, the entropy, and by studying the behavior in the limit T-->0 of the charge and spin susceptibilities. A detailed study of the thermodynamic quantities is also presented at finite temperature. This study evidences that a finite-range order persists for a wide range of the temperature, as shown by the behavior of the correlation functions and by the two-peak structure exhibited by the charge susceptibility and by the entropy. Moreover, the equations of motion formalism, together with the use of composite operators, allows us to exactly determine the set of elementary excitations. As a result, the density of states can be determined and a detailed analysis of the specific heat allows for identifying the excitations and for ascribing its two-peak structure to a redistribution of the charge density. PMID:18643230

Mancini, F; Mancini, F P

2008-06-16

420

Transition-event durations in one-dimensional activated processes  

NASA Astrophysics Data System (ADS)

Despite their importance in activated processes, transition-event durations-which are much shorter than first passage times-have not received a complete theoretical treatment. The authors therefore study the distribution ?b(t) of durations of transition events over a barrier in a one-dimensional system undergoing overdamped Langevin dynamics. The authors show that ?b(t) is determined by a Fokker-Planck equation with absorbing boundary conditions and obtain a number of results, including (i) the analytic form of the asymptotic short-time transient behavior, which is universal and independent of the potential function; (ii) the first nonuniversal correction to the short-time behavior leading to an estimate of a key physical time scale; (iii) following previous work, a recursive formulation for calculating, exactly, all moments of ?b based solely on the potential function-along with approximations for the distribution based on a small number of moments; and (iv) a high-barrier approximation to the long-time (t-->?) behavior of ?b(t). The authors also find that the mean event duration does not depend simply on the barrier-top frequency (curvature) but is sensitive to details of the potential. All of the analytic results are confirmed by transition-path-sampling simulations implemented in a novel way. Finally, the authors discuss which aspects of the duration distribution are expected to be general for more complex systems.

Zhang, Bin W.; Jasnow, David; Zuckerman, Daniel M.

2007-02-01

421

Nonequilibrium electronic transport in a one-dimensional Mott insulator  

SciTech Connect

We calculate the nonequilibrium electronic transport properties of a one-dimensional interacting chain at half filling, coupled to noninteracting leads. The interacting chain is initially in a Mott insulator state that is driven out of equilibrium by applying a strong bias voltage between the leads. For bias voltages above a certain threshold we observe the breakdown of the Mott insulator state and the establishment of a steady-state elec- tronic current through the system. Based on extensive time-dependent density-matrix renormalization-group simulations, we show that this steady-state current always has the same functional dependence on voltage, independent of the microscopic details of the model and we relate the value of the threshold to the Lieb-Wu gap. We frame our results in terms of the Landau-Zener dielectric breakdown picture. Finally, we also discuss the real-time evolution of the current, and characterize the current-carrying state resulting from the breakdown of the Mott insulator by computing the double occupancy, the spin structure factor, and the entanglement entropy.

Heidrich-Meisner, F. [Institut fur Physikalische Chemie der RWTH; Gonzalez, Ivan [Universidad de Santiago de Compostela; Al-Hassanieh, K. A. [Los Alamos National Laboratory (LANL); Feiguin, A. E. [University of Wyoming, Laramie; Rozenberg, M. J. [Universite Paris Sud, Orsay, France; Dagotto, Elbio R [ORNL

2010-01-01

422

Electronic effects of defects in one-dimensional channels  

NASA Astrophysics Data System (ADS)

As electronic devices shrink to the one-dimensional limit, unusual device physics can result, even at room temperature. Nanoscale conductors like single-walled carbon nanotubes (SWNTs) are particularly useful tools for experimentally investigating these effects. Our characterization of point defects in SWNTs has focused on these electronic consequences. A single scattering site in an otherwise quasi-ballistic SWNT introduces resistance, transconductance, and chemical sensitivity, and here we investigate these contributions using a combination of transport and scanning probe techniques. The transport measurements determine the two-terminal contributions over a wide range of bias, temperature, and environmental conditions, while the scanning probe work provides complementary confirmation that the effects originate at a particular site along the conduction path in a SWNT. Together, the combination proves that single point defects behave like scattering barriers having Poole-Frenkel transport characteristics. The Poole-Frenkel barriers have heights of 10 - 30 meV and gate-dependent widths that grow as large as 1 ?m due to the uniquely poor screening in one dimension. Poole-Frenkel characteristics suggest that the barriers contain at least one localized electronic state, and that this state primarily contributes to conduction under high bias or high temperature conditions. Because these localized states vary from one device to another, we hypothesize that each might be unique to a particular defect's chemical type.

Fuller, Elliot J.; Pan, Deng; Corso, Brad L.; Gul, O. Tolga; Collins, Philip G.

2013-09-01

423

One-dimensional simulation of lanthanide isotachophoresis using COMSOL.  

PubMed

Electrokinetic separations can be used to quickly separate rare earth metals to determine their forensic signature. In this work, we simulate the concentration and separation of trivalent lanthanide cations by isotachophoresis. A one-dimensional simulation is developed using COMSOL v4.0a, a commercial finite element simulator, to represent the isotachophoretic separation of three lanthanides: lanthanum, terbium, and lutetium. The binding ligand chosen for complexation with the lanthanides is ?-hydroxyisobutyric acid (HIBA) and the buffer system includes acetate, which also complexes with the lanthanides. The complexes formed between the three lanthanides, HIBA, and acetate are all considered in the simulation. We observe that the presence of only lanthanide:HIBA complexes in a buffer system with 10 mM HIBA causes the slowest lanthanide peak (lutetium) to split from the other analytes. The addition of lanthanide:acetate complexes into the simulation of the same buffer system eliminates this splitting. Decreasing the concentration of HIBA in the buffer to 7 mM causes the analyte stack to migrate faster through the capillary. PMID:22522543

Dixon, Derek R; Clark, Sue B; Ivory, Cornelius F

2012-03-01

424

Inelastic collapse in one-dimensional driven systems under gravity  

NASA Astrophysics Data System (ADS)

We study inelastic collapse in a one-dimensional N-particle system when the system is driven from below under gravity. We investigate the hard-sphere limit of inelastic soft-sphere systems by numerical simulations to find how the collision rate per particle ncoll increases as a function of the elastic constant of the sphere k when the restitution coefficient e is kept constant. For systems with large enough N?20, we find three regimes in e depending on the behavior of ncoll in the hard-sphere limit: (i) an uncollapsing regime for 1?e>ec1, where ncoll converges to a finite value, (ii) a logarithmically collapsing regime for ec1>e>ec2, where ncoll diverges as ncolllogk, and (iii) a power-law collapsing regime for ec2>e>0, where ncoll diverges as ncollk? with an exponent ? that depends on N. The power-law collapsing regime shrinks as N decreases and seems not to exist for the system with N=3, while, for large N, the size of the uncollapsing and the logarithmically collapsing regime decreases as ec1?1-2.6/N and ec2?1-3.0/N. We demonstrate that this difference between large and small systems exists already in the inelastic collapse without external drive and gravity.

Wakou, Jun'ichi; Kitagishi, Hiroyuki; Sakaue, Takahiro; Nakanishi, Hiizu

2013-04-01

425

Noise in one-dimensional metamaterials supporting magnetoinductive lattice waves  

NASA Astrophysics Data System (ADS)

Equivalent circuit models are presented for the propagation of noise in one-dimensional negative-index metamaterials based on split-ring resonators (SRRs) and rods. The SRRs are modeled as lossy lumped-element L-C resonators, whose reactive components provide the effect of a negative relative permeability over a restricted frequency range but whose resistive elements act as sources of propagation loss and Johnson noise. Similarly, the rod loading is modeled as lumped-element inductors, whose reactive components provide the effect of a negative relative permittivity but whose resistive elements introduce further loss and noise. Coupling between the magnetic resonators allows the propagation of magnetoinductive lattice waves. The effect on the effective medium properties is to shift the apparent magnetic resonance up in frequency by an amount depending on the coupling coefficient and to allow the propagation of noise waves within the resonator array over the entire magnetoinductive band. The model predicts all the details of the electromagnetic and magnetoinductive noise inside the array. However, it is shown that the observable effect outside the array matches the prediction of a simplified model based only on the modified effective medium properties.

Syms, R. R. A.; Sydoruk, O.; Solymar, L.

2013-04-01

426

Gravitational force in an infinite one-dimensional Poisson distribution.  

PubMed

We consider the statistical properties of the gravitational field F in an infinite one-dimensional homogeneous Poisson distribution of particles using an exponential cutoff of the pair interaction to control and study the divergences which arise. Deriving an exact analytic expression for the probability density function (PDF) P(F) , we show that it is badly defined in the limit in which the well-known Holtzmark distribution is obtained in the analogous three-dimensional case. A well-defined P(F) may, however, be obtained in the infinite range limit by an appropriate renormalization of the coupling strength giving a Gaussian form. Calculating the spatial correlation properties we show that this latter procedure has a trivial physical meaning. Finally we calculate the PDF and correlation properties of differences of forces (at separate spatial points), which are well defined without any renormalization. We explain that the convergence of these quantities is in fact sufficient to allow a physically meaningful infinite system limit to be defined for the clustering dynamics from Poissonian initial conditions. PMID:20365525

Gabrielli, A; Joyce, M

2010-02-01

427

Gravitational force in an infinite one-dimensional Poisson distribution  

NASA Astrophysics Data System (ADS)

We consider the statistical properties of the gravitational field F in an infinite one-dimensional homogeneous Poisson distribution of particles using an exponential cutoff of the pair interaction to control and study the divergences which arise. Deriving an exact analytic expression for the probability density function (PDF) P(F) , we show that it is badly defined in the limit in which the well-known Holtzmark distribution is obtained in the analogous three-dimensional case. A well-defined P(F) may, however, be obtained in the infinite range limit by an appropriate renormalization of the coupling strength giving a Gaussian form. Calculating the spatial correlation properties we show that this latter procedure has a trivial physical meaning. Finally we calculate the PDF and correlation properties of differences of forces (at separate spatial points), which are well defined without any renormalization. We explain that the convergence of these quantities is in fact sufficient to allow a physically meaningful infinite system limit to be defined for the clustering dynamics from Poissonian initial conditions.

Gabrielli, A.; Joyce, M.

2010-02-01

428

One-dimensional transient radiative transfer by lattice Boltzmann method.  

PubMed

The lattice Boltzmann method (LBM) is extended to solve transient radiative transfer in one-dimensional slab containing scattering media subjected to a collimated short laser irradiation. By using a fully implicit backward differencing scheme to discretize the transient term in the radiative transfer equation, a new type of lattice structure is devised. The accuracy and computational efficiency of this algorithm are examined firstly. Afterwards, effects of the medium properties such as the extinction coefficient, the scattering albedo and the anisotropy factor, and the shapes of laser pulse on time-resolved signals of transmittance and reflectance are investigated. Results of the present method are found to compare very well with the data from the literature. For an oblique incidence, the LBM results in this paper are compared with those by Monte Carlo method generated by ourselves. In addition, transient radiative transfer in a two-Layer inhomogeneous media subjected to a short square pulse irradiation is investigated. At last, the LBM is further extended to study the transient radiative transfer in homogeneous medium with a refractive index discontinuity irradiated by the short pulse laser. Several trends on the time-resolved signals different from those for refractive index of 1 (i.e. refractive-index-matched boundary) are observed and analysed. PMID:24150298

Zhang, Yong; Yi, Hongliang; Tan, Heping

2013-10-21

429

Dynamic response of one-dimensional bosons in a trap  

SciTech Connect

We calculate the dynamic structure factor S(q,{omega}) of a one-dimensional (1D) interacting Bose gas confined in a harmonic trap. The effective interaction depends on the strength of the confinement enforcing the (1D) motion of atoms; interaction may be further enhanced by superimposing an optical lattice on the trap potential. In the compressible state, we find that the smooth variation in the gas density around the trap center leads to softening of the singular behavior of S(q,{omega}) at the first Lieb excitation mode compared to the behavior predicted for homogeneous 1D systems. Nevertheless, the density-averaged response S(q,{omega}) remains a nonanalytic function of q and {omega} at the first Lieb excitation mode in the limit of weak trap confinement. The exponent of the power-law nonanalyticity is modified due to the inhomogeneity in a universal way and thus bears unambiguously the information about the (homogeneous) Lieb-Liniger model. A strong optical lattice causes formation of Mott phases. Deep in the Mott regime, we predict a semicircular peak in S(q,{omega}) centered at the on-site repulsion energy, {omega}=U. Similar peaks of smaller amplitudes exist at multiples of U as well. We explain the suppression of the dynamic response with entering into the Mott regime, observed recently by Clement et al. [Phys. Rev. Lett. 102, 155301 (2009)], based on an f-sum rule for the Bose-Hubbard model.

Golovach, Vitaly N. [Physics Department, Arnold Sommerfeld Center for Theoretical Physics, and Center for NanoScience, Ludwig-Maximilians-Universitaet, 80333 Munich (Germany); Minguzzi, Anna [Laboratoire de Physique et de Modelisation des Milieux Condenses, C.N.R.S., Universite Joseph Fourier, BP 166, 38042 Grenoble (France); Glazman, Leonid I. [Department of Physics, Yale University, New Haven, Connecticut 06520 (United States)

2009-10-15

430

One-Dimensional Burn Control in Fusion Reactors  

NASA Astrophysics Data System (ADS)

Control of plasma density and temperature magnitudes, as well as their profiles, are among the most fundamental problems in fusion reactors. Economic and technological constraints may require fusion reactors to operate at operating points for which an active control system may be necessary to stabilize the thermonuclear reaction. In [1], a zero-dimensional (0-D) nonlinear model involving approximate conservation equations for the energy and the density of ion species was used to synthesize a nonlinear feedback controller for stabilizing the burn condition of a fusion reactor. This result is exploited in this work to propose a controller that is able to stabilize the one-dimensional (1-D) burn dynamics. A simulation study is carried out to assess the performance of the controller and its effect on the plasma density and temperature profiles. The long-term goal is to develop model-based controllers for simultaneous kinetic profile regulation and burn condition control. [4pt] [1] E. Schuster, M. Krstic and G. Tynan, ``Burn control in fusion reactors via nonlinear stabilization techniques,'' Fusion Science and Technology, vol. 43, no. 1, pp. 18-37, January 2003.

Boyer, Mark D.; Schuster, Eugenio

2010-11-01

431

Single ions trapped in a one-dimensional optical lattice.  

PubMed

We report on three-dimensional optical trapping of single ions in a one-dimensional optical lattice formed by two counterpropagating laser beams. We characterize the trapping parameters of the standing-wave using the ion as a sensor stored in a hybrid trap consisting of a radio-frequency (rf), a dc, and the optical potential. When loading ions directly from the rf into the standing-wave trap, we observe a dominant heating rate. Monte Carlo simulations confirm rf-induced parametric excitations within the deep optical lattice as the main source. We demonstrate a way around this effect by an alternative transfer protocol which involves an intermediate step of optical confinement in a single-beam trap avoiding the temporal overlap of the standing-wave and the rf field. Implications arise for hybrid (rf-optical) and pure optical traps as platforms for ultracold chemistry experiments exploring atom-ion collisions or quantum simulation experiments with ions, or combinations of ions and atoms. PMID:23368193

Enderlein, Martin; Huber, Thomas; Schneider, Christian; Schaetz, Tobias

2012-12-05

432

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

433

Fractal geometry in an expanding, one-dimensional, Newtonian universe.  

PubMed

Observations of galaxies over large distances reveal the possibility of a fractal distribution of their positions. The source of fractal behavior is the lack of a length scale in the two body gravitational interaction. However, even with new, larger, sample sizes from recent surveys, it is difficult to extract information concerning fractal properties with confidence. Similarly, three-dimensional N-body simulations with a billion particles only provide a thousand particles per dimension, far too small for accurate conclusions. With one-dimensional models these limitations can be overcome by carrying out simulations with on the order of a quarter of a million particles without compromising the computation of the gravitational force. Here the multifractal properties of two of these models that incorporate different features of the dynamical equations governing the evolution of a matter dominated universe are compared. For each model at least two scaling regions are identified. By employing criteria from dynamical systems theory it is shown that only one of them can be geometrically significant. The results share important similarities with galaxy observations, such as hierarchical clustering and apparent bifractal geometry. They also provide insights concerning possible constraints on length and time scales for fractal structure. They clearly demonstrate that fractal geometry evolves in the mu (position, velocity) space. The observed patterns are simply a shadow (projection) of higher-dimensional structure. PMID:17930359

Miller, Bruce N; Rouet, Jean-Louis; Le Guirriec, Emmanuel

2007-09-14

434

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 (345)(32456274) 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

435

Copper(II)-lanthanide(III) coordination polymers constructed from pyridine-2,5-dicarboxylic acid: Preparation, crystal structure and photoluminescence  

NASA Astrophysics Data System (ADS)

A series of 3d-4f heterometallic coordination polymers, formulated as {[Cu3Ln2(pydc)6(H2O)12]4H2O}n [Ln=Tb (1), Eu (2), Dy (3), Ho (4), Lu (5)], {[CuNd2(pydc)4(H2O)3]H2O}n (6) and {[Cu3Pr2(pydc)6(H2O)13]4H2O}n (7) (where H2pydc=pyridine-2,5-dicarboxylic acid), have been hydrothermally prepared by reactions of H2pydc ligand with lanthanide ions in the presence of Cu(II) ion. X-ray crystal structure analysis reveals that these compounds exhibit rich structural chemistry. 1-5 are isomorphous and present a two-dimensional network constructed from Ln2Cu2L2(H2O)2 SBU rings and CuL2(H2O) building blocks. In 6, two-dimensional ladder-like layers based on Nd(III) belts and CuL2O2 units are assembled by H2pydc ligands into a three-dimensional open framework. Polymer 7 displays a two-dimensional wave-like layer structure containing two distinct ring units, in which a new coordination mode of the pydc2- ligand is observed. The results indicate that the coordination flexibility of the pydc2- ligand and lanthanide contraction effect play cooperative roles in the formation of coordination polymers with different polymeric architectures. Compounds 1-2 exhibit intense green and red luminescence emission characteristics of Tb(III) and Eu(III), respectively. Furthermore, elemental analyses (EA), infrared spectra (IR) and thermogravimetric analyses (TGA) of these compounds were also studied.

Xia, Zheng-Qiang; Wei, Qing; Chen, San-Ping; Feng, Xin-Ming; Xie, Gang; Qiao, Cheng-Fang; Zhang, Guo-Chun; Gao, Sheng-Li

2013-01-01

436

Accurate one-dimensional potential energy curve of the linear (H2)2 cluster  

NASA Astrophysics Data System (ADS)

We present a sub-0.3 K accuracy, ground-state one-dimensional potential energy curve of the metastable linear configuration of the (H2)2 cluster calculated exclusively with explicitly correlated Gaussian functions with shifted centers. The H2 internuclear distance is kept at the isolated H2 vibrational ground-state average value of 1.448 736 bohr and the intermonomer separation is varied between 2 and 100 bohrs. The analytical gradient of the energy with respect to the nonlinear parameters of the Gaussians (i.e., the exponents and the coordinates of the shifts) has been employed in the variational optimization of the wave function. Procedures for enlarging the basis set and for adjusting the centers of the Gaussians to the varying intermonomer separation have been developed and used in the calculations.

Tung, Wei-Cheng; Pavanello, Michele; Adamowicz, Ludwik

2010-09-01

437

Porous one-dimensional nanostructures through confined cooperative self-assembly.  

PubMed

We report a simple confined self-assembly process to synthesize nanoporous one-dimensional photoactive nanostructures. Through surfactant-assisted cooperative interactions (e.g., ?-? stacking, ligand coordination, and so forth) of the macrocyclic building block, zinc meso-tetra (4-pyridyl) porphyrin (ZnTPyP), self-assembled ZnTPyP nanowires and nanorods with controlled diameters and aspect ratios are prepared. Electron microscopy characterization in combination with X-ray diffraction and gas sorption experiments indicate that these materials exhibit stable single-crystalline and high surface area nanoporous frameworks with well-defined external morphology. Optical characterizations using UV-vis spectroscopy and fluorescence imaging and spectroscopy show enhanced collective optical properties over the individual chromophores (ZnTPyP), favorable for exciton formation and transport. PMID:22082076

Bai, Feng; Sun, Zaicheng; Wu, Huimeng; Haddad, Raid E; Coker, Eric N; Huang, Jian Yu; Rodriguez, Mark A; Fan, Hongyou

2011-11-18

438

Magnetopolarons in quasi-one-dimensional quantum-well wires  

NASA Astrophysics Data System (ADS)

The interaction of quasi-one-dimensional electrons and longitudinal-optical (LO) phonons in the presense of a quantizing magnetic field is calculated. Results are detailed presented for the polaron correction to the subband energies, the polaron cyclotron mass and the polaron effective mass. The calculations are done by using different approaches, Rayleigh-Schrdinger perturbation theory, Wigner-Brillouin perturbation theory, improved Wigner-Brillouin perturbation theory and Green's function technique. In the framework of a diagrammatic approach a modified Hartree-Fock approximation is developed, which allows the calculation of the quasi-particle properties of lower-dimensional semiconductor nanostructures in the subband space. It is shown that the Rayleigh-Schrdinger perturbation theory, improved Wigner-Brillouin perturbation theory and the modified Hartree-Fock approximation well describe the ground-state renormalization, but only the improved Wigner-Brillouin perturbation theory and the modified Hartree-Fock approximation well describe the bend-over and pinning behaviour of the subbands at the boundary of the phonon continuum. Rayleigh-Schrdinger and Wigner-Brillouin perturbation theories fail for the calculation of the renormalization of the excited subband energies in quantum-well wires with strong confining potential even for vanishing magnetic field and polaron momentum. In addition to the symmetric scattering processes, which are the only processes involved in the self-energy of the old-fashioned perturbation theories, Green's function technique allows also to calculate the contribution of all asymmetric scattering processes of two electrons by exchanging an optical phonon.

Wendler, L.

1999-10-01

439

One dimensional blood flow in a planetocentric orbit  

NASA Astrophysics Data System (ADS)

All life on earth is accustomed to the presence of gravity. When gravity is altered, biological processes can go awry. It is of great importance to ensure safety during a spaceflight. Long term exposure to microgravity can trigger detrimental physiological responses in the human body. Fluid redistribution coupled with fluid loss is one of the effects. In particular, in microgravity blood volume is shifted towards the thorax and head. Sympathetic nervous system-induced vasoconstriction is needed to maintain arterial pressure, while venoconstriction limits venous pooling of blood prevents further reductions in venous return of blood to the heart. In this paper, we modify an existing one dimensional blood flow model with the inclusion of the hydrostatic pressure gradient that further depends on the gravitational field modified by the oblateness and rotation of the Earth. We find that the velocity of the blood flow VB is inversely proportional to the blood specific volume d, also proportional to the oblateness harmonic coefficient J2, the angular velocity of the Earth ?E, and finally proportional to an arbitrary constant c. For c = -0.39073 and ?H = -0.5 mmHg, all orbits result to less blood flow velocities than that calculated on the surface of the Earth. From all considered orbits, elliptical polar orbit of eccentricity e = 0.2 exhibit the largest flow velocity VB = 1.031 m/s, followed by the orbits of inclination i = 45and 0. The Earth's oblateness and its rotation contribute a 0.7% difference to the blood flow velocity.

Haranas, Ioannis; Gkigkitzis, Ioannis

2012-05-01

440

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.

441

ONE-DIMENSIONAL ACCELERATOR IN PULSAR OUTER MAGNETOSPHERE REVISITED  

SciTech Connect

We re-examine the one-dimensional (1D) vacuum and nonvacuum accelerators in the outer magnetosphere of rotation-powered pulsars by considering the limit of trans-field height through pair-production process. In the original 1D nonvacuum outer gap model, both the Poisson equation for electrical potential and the Boltzmann equations of particles and gamma-rays are solved self-consistently by assuming the trans-field height as a free parameter, usually resulting in a narrow outer gap (i.e., gap length along magnetic field lines is short). In the modified 1D nonvacuum outer gap model, two improvements have been made: the trans-field height is limited by photon-photon pair production process and the outer boundary of the outer gap can be extended outside the light cylinder. Under the above assumptions, we self-consistently solve the Poisson equation for electrical potential, and the Boltzmann equations of electrons/positrons and gamma-rays in both vacuum and nonvacuum outer gaps for the parameters of both Vela and Geminga pulsars. We obtain an approximate geometry of the outer gap, i.e., the trans-field height is limited by the pair-production process and increases with the radial distance to the star, and the width of the outer gap starts at the inner boundary (near the null charge surface in the vacuum case) and ends at the outer boundary which is located inside or outside the light cylinder depending on the inclination angle. Our calculated results also indicate that gamma-ray spectrum from a wide outer gap is flatter than the one from a narrow outer gap and the relation between the electric field and trans-field height has an important effect on the structure of the outer gap.

Lin, G. F.; Zhang, L., E-mail: lizhang@ynu.edu.c [Department of Physics, Yunnan University, Kunming (China)

2009-07-10

442

Effective one-dimensional equation of motion for nuclear fission  

Microsoft Academic Search

An approach for describing the dynamics of nuclear fission in the framework of generalized quantum mechanics is discussed.\\u000a The collective kinetic energy is assumed to be two dimensional, and the reduced mass is allowed to vary with the coordinates.\\u000a The generalized calculus of variation is employed for minimizing the action after being properly quantized as required by\\u000a Hamilton's principle, employing

M. W. Morsy; Fathia A. E. A. Imam

1997-01-01

443

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(HBimcN)(HBimcT)(H2O)]3.5H2OEtOH (1a3.5H2OEtOH, H2Bimc=1H-benzimidazole-5-carboxylic acid) and [Cd(HBimcN)(HBimcT)(H2O)] (1b), and two Cu(HMBimc)-based coordination polymers, [Cu(HMBimcN)2(H2O)]1/2H2O (21/2H2O, H2MBimc=2-methyl-1H-benzimidazole-5-carboxylic acid) and [Cu(HMBimcT)2]2THFH2O (32THFH2O), were self-assembled from Cd(ClO4)26H2O/H2Bimc and Cu(ClO4)26H2O/H2MBimc systems, respectively. Compound 1a adopts a ladder-like chain structure, comprised of a hydrogen-bond-stabilized Cd2(HBimcN)2-metallocyclic stair and a 1D straight -(Cd-HBimcT)n- edge, whereas compound 1b exhibits a 2D (4,4)-rhombus layered structure, intercrossed by 1D -(Cd-HBimcN)n- chains and -(Cd-HBimcT)n- chains. Compound 2 shows a 1D double-stranded wave-like chain from two single-stranded wave-like -(Cu-HMBimcN)n- chains and compound 3 adopts a 2D (4,4)-topological layer structure, intercrossed by subunits of 1D -(Cu-HMBimcT)n- chains. Interestingly, a pair of tautomeric HBimc building blocksnormal (N or HBimcN) and tautomer (T or HBimcT)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

444

Functional tetrametallic linker modules for coordination polymers and metal-organic frameworks.  

PubMed

The new biphenol-based tetranucleating ligand, 2,2',6,6'-tetrakis(N,N-bis(2-pyridylmethyl)aminomethyl)-4,4'-biphenolate, dbpbp2-, comprises two linearly disposed phenolato-hinged dinucleating heptadentate units, each of which offer one O and three N donors to a total of four metal ions. The ligand has been isolated as the zinc chloride complex [Zn4(dbpbp)Cl4]2+, and the ZnII ions have been completely or partially substituted by CuII, FeIII, CoII, and CoIII in metathesis reactions. Similarly, the chloride ligands of [Zn4(dbpbp)Cl4]2+ have been exchanged for solvent molecules (acetonitrile and/or water) and bridging carboxylate ligands. The resulting complexes have been characterized by single-crystal X-ray diffraction, ESI mass spectrometry (ESI-MS), cyclic voltammetry (CV), and EPR spectroscopy. The structures containing [M4(dbpbp)Cl4]2+ with M = ZnII or CuII exhibit 2-D polymeric honeycomb sheets in which intermolecular M...Cl interactions bridge between adjacent [M4(dbpbp)Cl4]2+ cations. Two mixed-metal tetrabenzoate complexes [M4(dbpbp)(O2CC6H5)4]2+/3+ have also been prepared, namely a stoichiometric CuII2ZnII2 complex and a nonstoichiometric FeIII/ZnII system. In the latter case, ESI-MS identifies FeZn3, Fe2Zn2, and Zn4 species, and X-ray crystallography suggests an average composition of Fe0.8Zn3.2. Preparation of a CoII4 complex by metathesis was considerably more difficult than preparation of [Cu4(dbpbp)Cl4]2+, requiring both a large excess of the cobalt source and the presence of auxiliary benzoate. In the presence of 2 equiv of benzoate per starting [Zn4(dbpbp)Cl4]2+ unit and excess CoII, dioxygen binds as peroxide at each end of the molecule to give the CoIII4 complex [Co4(dbpbp)(O2)2(O2CC6H5)2]4+. This latter complex, together with new tetra- and hexametallic benzenedicarboxylato- and benzenetricarboxylato-bridged complexes of dinuclear [Co2(O2)(bpbp)]3+ units (bpbp- = 2,6-bis(N,N-bis-(2-pyridylmethyl)aminomethyl)-4-tert-butyl-phenolate), is a module for potential construction of 1-D and 2-D coordination polymers/metal-organic frameworks (MOFs) capable of reversible O2 binding. PMID:17315867

Johansson, Frank B; Bond, Andrew D; McKenzie, Christine J

2007-02-22

445

Theoretical studies in quasi-one-dimensional conductors  

NASA Astrophysics Data System (ADS)

This dissertation first focuses on recent developments in the theory of the quantum Hall effect (QHE) in