In this paper, convergence rates of the spectral distributions of quaternion self-dual Hermitian matrices are investigated. We show that under conditions of finite 6th moments, the expected spectral distribution of a large quaternion self-dual Hermitian matrix converges to the semicircular law in a rate of \(O(n^{-1/2})\) and the spectral distribution itself converges to the semicircular law in rates \(O_p(n^{-2/5})\) and \(O_{a.s.}(n^{-2/5+\eta })\). Those results include GSE as a special case. 相似文献
According to the elastic-viscoelastic correspondence principle, an elastic microme- chanical framework taking the inclusion-matrix interface effect into account is extended for predicting viscoelastic properties of asphalt mixture, which is simply treated as elastic coarse aggregate inclusions periodically and isotropically embedded in a viscoelastic asphalt mastic matrix. The Burgers model is adopted for characterizing the matrix mechanical behavior, so that the homogenized relaxation modulus of asphalt mixture in compression creep is derived. After a series of uniaxial compression creep tests are performed on asphalt mastic in different temperature and stress conditions in order to determine the matrix constitutive parameters, the framework presented is validated by comparison with the experiment, and then some predictions of uniaxial compression creep behavior of asphalt mixture in different temperature and stress conditions are given. 相似文献
Ultrasound-aided electric discharge machining(EDM) is an emerging technology for producing hollow nickel microspheres.This technology combines traditional EDM with the cavitation and vibration effects of ultrasound to produce hollow microspheres.In this paper,ultrasound-aided EDM was carried out in a kerosene medium(the working solution).The effects of various parameters on the sizes of microspheres were investigated using scanning electronic microscopy(SEM).Smileview software was used to measure the sizes of the microspheres.Originpro software was used for statistical analysis to determine the size distributions of the microspheres.To study the effects of the system parameters on the sizes of the microspheres,we first investigated the necessity of using an ultrasonic wave with EDM.After comparing the experimental results with and without the ultrasonic field,we found that ultrasound-induced cavitation and vibration effects reduced the diameters of the microspheres.We then studied the effects of several electrical parameters,including the arc current,pulse width,and gap voltage,on the sizes of the microspheres at an ultrasound frequency of 40 kHz.Smaller microspheres could be obtained by lowering the arc current,pulse width,and gap voltage. 相似文献
The photophysical properties of hexadecyl 4-biphenylamino benzoate (HBAB), the molecule of which possesses a polar end composed of donor (triphenylamino group) and acceptor (ester group) and a long non-polar alkyl tail, have been carefully studied in different conditions. The results show that the twisted intramolecular charge transfer (TICT) emission is given in polar solvents at room temperature and intramolecular charge transfer (ICT) emission is given at 77 K. These can be supported by the solvent effect, temperature effect and the quenching process. 相似文献
The photophysical processes of 1,3-dicarbazolypropane (DCZP), which possesses two fluorogen, carbazoly, and one carbonic chain composed of three carbon atoms, were studied. The formation of intermolecular excimer, intramolecular excimer and triple exciplexes have been investigated in the system of DCZP and 1,4-dinitrilebenzene (DNB) with steady state fluorescence spectroscopy. The experimental results show that with the addition of DNB into the lower concentration solution of DCZP in benzene, the fluorescence of intramolecular excimer of DCZP, (D-D)*, is quenched while the ((D-D)A)* type triple exciplex (one molecule of DCZP with one molecule of DNB) is formed and with the addition of DNB into higher concentration solution of DCZP, the formation of (DDA)* type triple exciplex (two molecules of DCZP with one molecule of DNB) is also confirmed. 相似文献
Here, two series of novel ursolic acid-based 1,2,4-triazolo[1,5-a]pyrimidines derivatives were synthesized and screened for their anti-inflammatory activity by evaluating their inhibition effect of using LPS-induced inflammatory response in RAW 264.7 macrophages in vitro; the effects of different concentrations of the compounds on the secretion of nitric oxide (NO) and inflammatory cytokines including TNF-α and IL-6 were evaluated. Their toxicity was also assessed in vitro. Results showed that the most prominent compound 3 could significantly decrease production of the above inflammatory factors. Docking study was performed for the representative compounds 3, UA, and Celecoxib to explain their interaction with cyclooxygenase-2 (COX-2) receptor active site. In vitro enzyme study implied that compound 3 exerted its anti-inflammatory activity through COX-2 inhibition.
Two unusual triterpenes, ilelic acids A (1) and B (2), together with their biosynthetic related compounds ilelic acids C (3) and D (4) were isolated from the leaves of Ilex latifolia. Their structures with absolute configurations were elucidated by spectroscopic analysis and modified Mosher's method. The plausible biogenetic pathway of 1 and 2 is proposed. These triterpenes exhibited a potent inhibitory effect on MCF-7 and MDA-MB-231 cells. 相似文献