585 research outputs found
Study on Ultrasonic Degradation of Pentachlorophenol Solution
Pentachlorophenol (PCP) ion was degraded by ultrasound at 25 C. Four aspects that could affect the degradation of PCP were investigated, i.e. initial pH of solution, initial concentration of pentachlorophenol ion, different sound intensity with catalyst and different frequencies of ultrasound. Results showed that PCP ion could be ultrasonic degraded
totally after 3 hour treatment if CCl4, which can provide free radical, was added in solution. The mechanism of ultrasonic degradation was considered as free radical oxidation by adding n-butyl alcohol as free radical scavenger
Applications of Contact Length Models in Grinding Processes
yesThe nature of the contact behaviour between a grinding wheel and a workpiece in the grinding process has a great effect on the grinding temperature and the occurrence of thermal induced damage on the ground workpiece. It is found that the measured contact length le in grinding is considerably longer than the geometric contact length lg and the contact length due to wheel-workpiece deflection lf. The orthogonal relationship among the contact lengths, i.e. lc2 = (Rrlf)2 + lg2, reveals how the grinding force and grinding depth of cut affect the overall contact length between a grinding wheel and a workpiece in grinding processes. To make the orthogonal contact length model easy to use, attempts on modification of the model are carried out in the present study, in which the input variable of the model, Fn’, is replaced by a well-established empirical formula and specific grinding power. By applying the modified model in this paper, an analysis on the contributions of the individual factors, i.e. the wheel/workpiece deformation and the grinding depth of cut, on the overall grinding contact length is conducted under a wide range of grinding applications, i.e. from precise/shallow grinding to deep/creep-feed grinding. Finally, using a case study, the criterion of using geometric contact length lg to represent the real contact length lc, in terms of convenience versus accuracy, is discussed
Discrete-time quantum walks on one-dimensional lattices
In this paper, we study discrete-time quantum walks on one-dimensional
lattices. We find that the coherent dynamics depends on the initial states and
coin parameters. For infinite size of lattice, we derive an explicit expression
for the return probability, which shows scaling behavior
and does not depends on the initial states of the walk. In the long-time limit,
the probability distribution shows various patterns, depending on the initial
states, coin parameters and the lattice size. The average mixing time
closes to the limiting probability in linear (size of the
lattice) for large values of thresholds . Finally, we introduce
another kind of quantum walk on infinite or even-numbered size of lattices, and
show that the walk is equivalent to the traditional quantum walk with
symmetrical initial state and coin parameter.Comment: 17 pages research not
Correlation effects in ionic crystals: I. The cohesive energy of MgO
High-level quantum-chemical calculations, using the coupled-cluster approach
and extended one-particle basis sets, have been performed for (Mg2+)n (O2-)m
clusters embedded in a Madelung potential. The results of these calculations
are used for setting up an incremental expansion for the correlation energy of
bulk MgO. This way, 96% of the experimental cohesive energy of the MgO crystal
is recovered. It is shown that only 60% of the correlation contribution to the
cohesive energy is of intra-ionic origin, the remaining part being caused by
van der Waals-like inter-ionic excitations.Comment: LaTeX, 20 pages, no figure
Pharmacological characterization of novel synthetic opioids (NSO) found in the recreational drug marketplace
Novel synthetic opioids (NSO) are increasingly encountered in illicit heroin and counterfeit pain pills. Many NSO are resurrected from older biomedical literature or patent applications, so limited information is available about their biological effects. Here we examined the pharmacology of three structurally-distinct NSO found in the recreational drug market: N-(1-(2-phenylethyl)-4-piperidinyl)-N-phenylbutyramide (butyrylfentanyl), 3,4-dichloro-N-[(1R,2R)-2-(dimethylamino)cyclohexyl]-N-methylbenzamide (U-47700) and 1-cyclohexyl-4-(1,2-diphenylethyl)piperazine (MT-45). Radioligand binding and GTPγS functional assays were carried out in cells transfected with murine mu- (MOR-1), delta- (DOR-1) or kappa-opioid receptors (KOR-1). Antinociceptive effects were determined using the radiant heat tail flick technique in mice, and opioid specificity was assessed with the mu-opioid antagonist naloxone. Butyrylfentanyl, U-47700 and MT-45 displayed nM affinities at MOR-1, but were less potent than morphine, and had much weaker effects at DOR-1 and KOR-1. All NSO exhibited agonist actions at MOR-1 in the GTPγS assay. Butyrylfentanyl and U-47700 were 31- and 12-fold more potent than morphine in the tail flick assay, whereas MT-45 was equipotent with morphine. Analgesic effects were reversed by naloxone and absent in genetically-engineered mice lacking MOR-1. Our findings confirm that butyrylfentanyl, U-47700 and MT-45 are selective MOR-1 agonists with in vitro affinities less than morphine. However, analgesic potencies vary more than 30-fold across the compounds, and in vitro binding affinity does not predict in vivo potency. Taken together, our findings highlight the risks to humans who may unknowingly be exposed to these and other NSO when taking adulterated heroin or counterfeit pain medications. This article is part of the Special Issue entitled ‘Designer Drugs and Legal Highs.’ © 201
Comparative mapping and targeted-capture sequencing of the gametocidal loci in Aegilops sharonensis
Gametocidal (Gc) chromosomes or elements in species such as Aegilops sharonensis are preferentially transmitted to the next generation through both the male and female gametes when introduced into wheat. Furthermore, any genes, e.g. genes that control agronomically important traits, showing complete linkage with gametocidal elements, are also transmitted preferentially to the next generation without the need for selection. The mechanism for the preferential transmission of the gametocidal elements appears to occur by the induction of extensive chromosome damage in any gametes that lack the gametocidal chromosome in question. Previous studies on the mechanism of the gametocidal action in Ae. sharonensis indicates that at least two-linked elements are involved. The first, the ‘breaker’ element, induces chromosome breakage in gametes, which have lost the gametocidal elements while the second, the ‘inhibitor’ element, prevents the chromosome breakage action of the ‘breaker’ element in gametes, which carry the Gc elements. In this study, we have used comparative genomic studies to map 54 single nucleotide polymorphism (SNP) markers in an Ae. sharonensis 4SshL introgression segment in wheat and have also identified 18 candidate genes in Ae. sharonensis for the ‘breaker’ element through targeted sequencing of this 4SshL introgression segment. This valuable genomic resource will aide in further mapping the Gc locus that could be exploited in wheat breeding to produce new, superior varieties of wheat
Influence of the starting composition on the structural and superconducting properties of MgB2 phase
We report the preparation of MgB (0x0.5) compounds
with the nominal compositions. Single phase MgB was obtained for x=0
sample. For 0x0.5, MgB coexists with "MgB" and the amount
of MgB increases with x. With the increase of x, the lattice parameter
of "MgB" increases and the lattice parameter
decreases, correspondingly T of MgB decreases. The results
were discussed in terms of the presence of Mg vacancies or B interstitials in
the MgB structure. This work is helpful to the understanding of the
MgB films with different T, as well as the Mg site doping effect
for MgB.Comment: 11 pages, 4 figure
Partial wave analysis of J/\psi \to \gamma \phi \phi
Using events collected in the BESII detector, the
radiative decay is
studied. The invariant mass distribution exhibits a near-threshold
enhancement that peaks around 2.24 GeV/.
A partial wave analysis shows that the structure is dominated by a
state () with a mass of
GeV/ and a width of GeV/. The
product branching fraction is: .Comment: 11 pages, 4 figures. corrected proof for journa
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