144 research outputs found
Neutral operator with variable parameter and third-order neutral differential equation
Additional file 1. The TRS sequences of structural genes in the HP-PRRSV/SD16 genome (GenBank: JX087437)
Random Copolycarbonates Based on a Renewable Bicyclic Diol Derived from Citric Acid
To
address the poor thermal stability of isohexides while at the
same time retain rigidity, we developed a novel bicyclic diol octahydro-2,5-pentalenediol
(OPD) from naturally occurring citric acid in this study. Owing to
the bicyclic skeleton composed of two fused cyclopentane rings, OPD
is supposed to have perfect rigidity but higher thermal stability
compared to isohexides. Herein, OPD was first converted to octahydro-2,5-pentalenediol
bisÂ(methyl carbonate) (OPBMC) by reacting with dimethyl carbonate.
The absolute stereochemistry of OPBMC was investigated by 2D <sup>1</sup>H NMR and <sup>13</sup>C NMR as well as single crystal X-ray
diffraction. By polymerization of OPBMC with several aliphatic diols
[1,8-octanediol (A<sub>8</sub>), 1,10-decanediol (A<sub>10</sub>),
and 1,12-dodeacnediol (A<sub>12</sub>)] and alicyclic diols [1,4-cyclohexaneÂdimethanol
(CHDM), 1,2,2-trimethylÂcyclopentane-1,3-dimethanol (TCDM), and
octahydro-2,5-pentalenediol (OPD)], a series of bio-based copolycarbonates
(co-PCs) with intriguing properties were synthesized. NMR spectra
revealed that the stereochemistry of OPBMC was preserved after polymerization.
Both differential scanning calorimetry and wide-angle X-ray diffraction
analyses revealed that co-PCs made from A<sub>8</sub>, A<sub>10</sub>, A<sub>12</sub>, and OPD are semicrystalline, while co-PCs based
on CHDM and TCDM are amorphous. A relatively high <i>T</i><sub>5%</sub> of 276 °C and outstanding high <i>T</i><sub>g</sub> up to 80.4 °C were detected for fully OPD-based
co-PC, confirming the excellent thermal stability and rigidity of
OPD. This work addresses some critical needs for high performance
polymers such as improving the sustainability of raw materials and
achieving both high <i>T</i><sub>g</sub> values and thermal
stability
The ratio of the number of final recovered nodes by ClusterRank to those by out-degree centrality, PageRank and LeaderRank.
<p>The non-overlapped nodes in the top-50 lists are initially infected. We set . Each data point is obtained by averaging over 100 independent runs.</p
Kendall’s tau between ranking scores provided by different methods and the real spreading abilities.
<p>Here we focus on the ranks of the top- ( = 20 and 50) nodes with maximal out-degrees. We abbreviate ClusterRank, LeaderRank, PageRank and Out-degree centrality by CR, LR, PR and DR, respectively.</p
An example network with 38 nodes and 110 directed edges.
<p>Although nodes 0 and 37 have the same out-degree, node 37 is of higher influence (subject to spreading dynamics) than node 0. The clustering coefficients of these two nodes are and .</p
for top- ranked nodes by out-degree centrality (squares), PageRank (diamond), LeaderRank (triangle) and ClusterRank (circles).
<p>We set and . Each data point is obtained by averaging over 100 independent runs.</p
Kinetic Aspects for the Reduction of CO<sub>2</sub> and CS<sub>2</sub> with Mixed-Ligand Ruthenium(II) Hydride Complexes Containing Phosphine and Bipyridine
A new
water-soluble ruthenium hydride complex [RuÂ(H)Â(bpy)<sub>2</sub>(PTA)]ÂPF<sub>6</sub> (bpy = 2,2′-bipyridine, PTA = 1,3,5-triaza-7-phosphaadamantane)
(<b>1a</b>) was prepared. <b>1a</b> reacted with CO<sub>2</sub> and CS<sub>2</sub> to give the corresponding formate and
dithioformate complexes, respectively. Both the insertions of CO<sub>2</sub> and CS<sub>2</sub> into the Ru–H bond of <b>1a</b> followed second-order kinetics. The second-order rate constant (<i>k</i><sub>2</sub>) of CO<sub>2</sub> insertion reaction varied
from (9.40 ± 0.41) × 10<sup>–4</sup> M<sup>–1</sup> s<sup>–1</sup> in acetone to (1.13 ± 0.08) × 10<sup>–1</sup> M<sup>–1</sup> s<sup>–1</sup> in methanol;
moreover, the lnÂ(<i>k</i><sub>2</sub>) is in good linear
relationship with the acceptor number (AN) of the solvent used. Although,
the <i>k</i><sub>2</sub> of CS<sub>2</sub> insertion reaction
ranged from (3.43 ± 0.10) M<sup>–1</sup> s<sup>–1</sup> in methanol to (24.0 ± 0.5) M<sup>–1</sup> s<sup>–1</sup> in <i>N</i>,<i>N</i>-dimethylformamide, which
is 1000 times faster than CO<sub>2</sub> insertion. Generally, the <i>k</i><sub>2</sub> of CS<sub>2</sub> insertion increased with
the static dielectric constant (<i>D</i><sub>s</sub>) of
the reaction medium investigated. For comparison purposes, we further
investigated the reactivity of [RuÂ(H)Â(bpy)<sub>2</sub>(PPh<sub>3</sub>)]ÂPF<sub>6</sub> (PPh<sub>3</sub> = triphenylphosphine) (<b>1b</b>) with CO<sub>2</sub> and CS<sub>2</sub>. <b>1b</b> reacted
with CO<sub>2</sub> slowly in the methanol with a <i>k</i><sub>2</sub> of (1.46 ± 0.09) × 10<sup>–3</sup> M<sup>–1</sup> s<sup>–1</sup>, yielding a formate complex
[RuÂ(η<sup>1</sup>-OCÂ(H)î—»O)Â(bpy)<sub>2</sub>(PPh<sub>3</sub>)]ÂPF<sub>6</sub> (<b>2b</b>). The reaction of <b>1b</b> with CS<sub>2</sub> is 1000 times faster than that of CO<sub>2</sub>. The structures of <b>1a</b>, <b>1b</b>, and <b>2b</b> were determined by X-ray crystallographic analysis
The dependence of on parameter .
<p>The initially infected nodes are the top-50 nodes obtained by out-degree centrality (squares), PageRank (diamonds), LeaderRank (triangles) and ClusterRank (circles). We set . Each data point is obtained by averaging over 100 independent runs.</p
Ranking correlation measured by Kendall’s tau between different methods.
<p>Here we focus on the ranks of the top- ( = 20 and 50) nodes with maximal out-degrees. We abbreviate ClusterRank, LeaderRank, PageRank and Out-degree centrality by CR, LR, PR and DR, respectively.</p
The dependance of on parameter in undirected Delicious and Cond-mat networks. We set .
<p>In (a) and (c), the initial infected nodes are those non-overlapped nodes in the top-50 places regardless of whether they are connected or not. In (b) and (d), the initial infected nodes are the non-overlapped nodes in top-50 places under constraint that any two of them are not connected. Each data point is obtained by averaging over 100 independent runs.</p
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