335 research outputs found
Minimizing Total Weighted Completion Time on Single Machine with Past-Sequence-Dependent Setup Times and Exponential Time-Dependent and Position-Dependent Learning Effects
This paper addresses a single-machine problem in which the past-sequence-dependent (p-s-d) setup times and exponential time-dependent and position-dependent learning effects are considered. By the exponential time-dependent learning effect, it means that the processing time of a job is defined by an exponent function of the total actual processing time of the already processed jobs. The setup times are proportional to the length of the already processed jobs. The aim is to minimize the total weighted completion time, this is an NP-hard problem. Under certain conditions, it is shown that the classical WSPT rule is optimal for the problem
Do coupling exciton and oscillation of electron-hole pair exist in neutral and charged pi-dimeric quinquethiophenes?
Optical physical properties of neutral and charged quinquethiophene monomer, and neutral and cationic pi-dimeric quinquethiophenes were investigated with density functional theory as well as the two dimensional (2D) site (transition density matrix) and three dimensional (3D) cube (transition density and charge difference density) representations, stimulated by the recent experimental report [T. Sakai , J. Am. Chem. Soc. 127, 8082 (2005)]. Transition density shows the orientation and strength of the transition dipole moment of neutral and charged quinquethiophene monomer, and charge difference density reveals the orientation and result of the charge transfer in neutral and charged quinquethiophene monomer. To study if coupling exciton and oscillation of electron-hole pair exist in neutral and cationic pi-dimeric quinquethiophenes, the coupling constants J (coupling exciton of electron-hole pair) and K (coupling oscillation of electron-hole pair) were introduced to the exciton coordinate and momentum operators, respectively, and the 2D and 3D analysis methods were further developed by extending our previous theoretical methods [M. T. Sun, J. Chem. Phys. 124, 054903 (2006)]. With the new developed 2D and 3D analysis methods, we investigated the excited state properties of neutral and cationic pi-dimeric quinquethiophenes, especially on the coupling exciton and oscillation of electron-hole pair between monomers. The 2D results show that there is neither coupling exciton (J=0) nor oscillation (K=0) of electron-hole pair in neutral pi-dimeric quinquethiophenes. For some excited states of cationic pi-dimeric quinquethiophenes, there is no coupling exciton (J=0), but there is coupling oscillation (K not equal 0); while for some excited states, there are both coupling exciton and coupling oscillator simultaneously (J not equal 0 and K not equal 0). The strength of transition dipole moments of pi-dimeric quinquethiophenes were interpreted with 3D transition density, which reveals the orientations of their two subtransition dipole moments. The 3D charge transition density reveals the orientation and result of intermonomer and/or intramonomer charge transfer. The calculated results reveal that excited state properties of neutral pi-dimeric quinquethiophene are significantly different from those of the cationic pi-dimeric quinquethiophenes
Fuzzy hypergroups based on fuzzy relations
AbstractBased on fuzzy reasoning in fuzzy logic, this paper studies a fuzzy hyperoperation and a fuzzy hypergroupoid associated with a fuzzy relation. A sufficient and necessary condition for such a fuzzy hypergroupoid being a fuzzy hypergroup is given, and the properties of the fuzzy hypergroups associated with fuzzy relations are investigated. Furthermore, the definition of normal fuzzy hypergroups is put forward and it is shown that the category NFHG of normal fuzzy hypergroups satisfies all the axioms of topos except for the subobject classifier axiom
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Syntheses and structures of new inorganic borates
Several new solid-state inorganic borates have been prepared and
characterized. Single crystals of the simple orthoborate ScB0₃ were
grown and its structure was determined by single-crystal X-ray
methods. The new borates Li₃Sc(B0₃)₂, LaSc₃(B0₃)₄, NdSc₃(B0₃)₄,
SrNaB0₃, and Li4Ln4MB90₂₃ (Ln = Y, Er, and Gd; M = Al and Ga) were
identified from phase analyses in the systems Li₂0-Sc₂0₃-B₂0₃,
La₂0₃-Sc₂0₃-B₂0₃, Nd₂0₃-Sc₂0₃-B₂0₃, SrO-Na₂0-B₂0₃, and Li₂0-Ln₂0₃-
M₂0₃-B₂0₃. Structural characteristics of these compounds have been
established by single-crystal X-ray methods. The orthoborate
Li₃Sc(B03)₂ exhibits strings of alternating Sc-centered octahedra
and Li-centered rectangular planes. The compounds LaSc₃(B0₃)₄ and
NdSc₃(B0₃)₄ are isostructural to other examples of the mineral
Huntite. The La derivative crystallizes in a monoclinic space group
with no evidence obtained for a phase transition to a higher symmetry
variant. The Nd derivative crystallizes in a high symmetry,
rhombohedral structure. The structure of SrNaB0₃ is similar to
that of the compound K₂CO₃, exhibiting a small distortion of the
packing of the Sr²⁺ and 0²⁻ ions from that observed for the Ba²⁺ and
0²⁻ ions in the oxide BaNi0₃. The structure of the compound
Li4Ln4MB80₂₃ contains the unique, isolated borate ring [B8₈0₂₀ ]16-.
These rings stack over fused rings of Ln-centered square antiprisms
to afford one-dimensional channels filled with Li atoms and an
orthoborate B0₃ group.
Optical properties including fluorescence, infrared absorption,
and second harmonic generation have been measured for the compounds
Li3Sc(B0₃)₂, LaSc₃(B0₃)₄, and NdSc₃(B0₃)₄. When doped with the ion
Cr³⁺, the compounds Li₃Sc(B0₃)₂ and LaSc₃(B0₃)₄ exhibit broad
emission bands in the near infrared, indicating the presence of weak
crystal fields at the SO⁺ (Cr³⁺) sites. Energy transfer is observed
in the doped compound Cr³⁺:NdSc₃(B03)₄; excitation into the Cr
³⁺
absorption band affords strong luminescence only from the Nd3⁺ ion.
The low conversion efficiency of the compound LaSc₃(B0₃)₄ for second
harmonic generation of the 1064 nm line of a Nd
³⁺ :YAG laser is
rationalized from the symmetry characteristics of the calculated
components of the hyperpolarizability tensor
Activated Vibrational Modes and Fermi Resonance in Tip-Enhanced Raman Spectroscopy
Using p-aminothiophenol (PATP) molecules on a gold substrate as prototypical
examples and high vacuum tip-enhanced Raman spectroscopy (HV-TERS), we show
that the vibrational spectra of those molecules are distinctly different from
those in typical surface-enhanced Raman spectroscopy. Detailed first-principles
calculations help to assign the Raman peaks in the TERS measurements as Raman
active and infrared (IR) active vibrational modes of dimercaptoazobenzene
(DMAB), thus providing strong spectroscopic evidence for the conversion of PATP
dimerization to DMAB. The activation of the IR active modes is due to enhanced
electromagnetic field gradient effects within the gap region of the highly
asymmetric tip-surface geometry. Our TERS measurements also realize splitting
of certain vibrational modes due to Fermi resonance between a fundamental mode
and the overtone of a different mode or a combinational mode. These findings
help to broaden the versatility of TERS as a promising technique for
ultrasensitive molecular spectroscopy
DSCALE_mod16: A Model for Disaggregating Microwave Satellite Soil Moisture with Land Surface Evapotranspiration Products and Gridded Meteorological Data
Improving the spatial resolution of microwave satellite soil moisture (SM) products is important for various applications. Most of the downscaling methods that fuse optical/thermal and microwave data rely on remotely sensed land surface temperature (LST) or LST-derived SM indexes (SMIs). However, these methods suffer from the problems of “cloud contamination”, “decomposing uncertainty”, and “decoupling effect”. This study presents a new downscaling method, referred to as DSCALE_mod16, without using LST and LST-derived SMIs. This model combines MODIS ET products and a gridded meteorological data set to obtain Land surface Evaporative Efficiency (LEE) as the main downscaling factor. A cosine-square form of downscaling function was adopted to represent the quantitative relationship between LEE and SM. Taking the central part of the United States as the case study area, we downscaled SMAP (Soil Moisture Active and Passive) SM products with an original resolution of 36km to a resolution of 500m. The study period spans more than three years from 2015 to 2018. In situ SM measurements from three sparse networks and three core validation sites (CVS) were used to evaluate the downscaling model. The evaluation results indicate that the downscaled SM values maintain the spatial dynamic range of original SM data while providing more spatial details. Moreover, the moisture mass is conserved during the downscaling process. The downscaled SM values have a good agreement with in situ SM measurements. The unbiased root-mean-square errors (ubRMSEs) of downscaled SM values is 0.035 m3/m3 at Fort Cobb, 0.026 m3/m3 at Little Washita, and 0.055 m3/m3 at South Fork, which are comparable to ubRMSEs of original SM estimates at these three CVS
Dynamic neuronal regulatory network during the progression of Alzheimer’s disease suggests an adaptive survival strategy
Identification and evaluation of the role of the manganese efflux protein in Deinococcus radiodurans
<p>Abstract</p> <p>Background</p> <p><it>Deinococcus radiodurans </it>accumulates high levels of manganese ions, and this is believed to be correlated with the radiation resistance ability of this microorganism. However, the maintenance of manganese ion homeostasis in <it>D. radiodurans </it>remains to be investigated.</p> <p>Results</p> <p>In this study, we identified the manganese efflux protein (MntE) in <it>D. radiodurans</it>. The null mutant of <it>mntE </it>was more sensitive than the wild-type strain to manganese ions, and the growth of the <it>mntE </it>mutant was delayed in manganese-supplemented media. Furthermore, there was a substantial increase in the <it>in vivo </it>concentration of manganese ions. Consistent with these characteristics, the <it>mntE </it>mutant was more resistant to H<sub>2</sub>O<sub>2</sub>, ultraviolet rays, and γ-radiation. The intracellular protein oxidation (carbonylation) level of the mutant strain was remarkably lower than that of the wild-type strain.</p> <p>Conclusions</p> <p>Our results indicated that <it>dr1236 </it>is indeed a <it>mntE </it>homologue and is indispensable for maintaining manganese homeostasis in <it>D. radiodurans</it>. The data also provide additional evidence for the involvement of intracellular manganese ions in the radiation resistance of <it>D. radiodurans</it>.</p
Identification and evaluation of the role of the manganese efflux protein in Deinococcus radiodurans
<p>Abstract</p> <p>Background</p> <p><it>Deinococcus radiodurans </it>accumulates high levels of manganese ions, and this is believed to be correlated with the radiation resistance ability of this microorganism. However, the maintenance of manganese ion homeostasis in <it>D. radiodurans </it>remains to be investigated.</p> <p>Results</p> <p>In this study, we identified the manganese efflux protein (MntE) in <it>D. radiodurans</it>. The null mutant of <it>mntE </it>was more sensitive than the wild-type strain to manganese ions, and the growth of the <it>mntE </it>mutant was delayed in manganese-supplemented media. Furthermore, there was a substantial increase in the <it>in vivo </it>concentration of manganese ions. Consistent with these characteristics, the <it>mntE </it>mutant was more resistant to H<sub>2</sub>O<sub>2</sub>, ultraviolet rays, and γ-radiation. The intracellular protein oxidation (carbonylation) level of the mutant strain was remarkably lower than that of the wild-type strain.</p> <p>Conclusions</p> <p>Our results indicated that <it>dr1236 </it>is indeed a <it>mntE </it>homologue and is indispensable for maintaining manganese homeostasis in <it>D. radiodurans</it>. The data also provide additional evidence for the involvement of intracellular manganese ions in the radiation resistance of <it>D. radiodurans</it>.</p
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