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991.
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   
992.
白继元  贺泽龙  杨守斌 《物理学报》2014,63(1):17303-017303
利用非平衡格林函数方法,理论研究每臂中嵌有一个平行耦合双量子点分子的A-B干涉仪(平行耦合双量子点分子A-B干涉仪)的电荷及其自旋输运性质.无外磁场时,与每臂中嵌有一个量子点的A-B干涉仪相比较,平行耦合双量子点分子A-B干涉仪中电子隧穿变得更加容易发生.当平行耦合双量子点分子A-B干涉仪中引入外磁场时,能够在电导能谱中观察到一个Fano共振和一个反共振,这两种输运状态在磁场取适当数值时能够同时消失.此外,通过调节左右两电极间的偏压、磁通和Rashba自旋轨道相互作用,可以对体系自旋输运进行调控.  相似文献   
993.
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   
994.
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   
995.
Photophysical process of hexadecyl 4-biphenylamino benzoate   总被引:5,自引:0,他引:5  
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   
996.
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   
997.
随着第四代反应堆以及先进核能利用系统的发展,对中子核数据提出了高精度、多核素、宽能区的新要求.目前,中国核数据评价库(CENDL库)中相关核裂变的数据较缺失,不足以满足当前核能发展的需求.因此,建立面向中子核数据需求的可靠计算方法和工具变得极为重要.本文基于Monte-Carlo方法建立了裂变碎片质量动能计算模型,研究了中低能中子诱发232Th(n,f)反应发射中子前裂变碎片的分布特性.对于裂变碎片质量分布,本模型计算结果与实验值最大偏差约1%,与GEF, TALYS程序计算结果 (与实验值最大偏差约2%)相比具有一定优势.对于发射中子前裂变碎片动能分布,本模型计算结果与实验数据一致.结果表明,所发展的计算模型能够较好地预测232Th(n,f)反应发射中子前裂变碎片数据,为中子诱发锕系核裂变反应计算提供一种新思路.  相似文献   
998.
因为寿命长,并且原子间相互作用容易操控,所以里德堡原子在量子信息与量子光学领域具有极大的吸引力.特别地,偶极阻塞效应成为执行很多量子信息处理任务的物理资源.本文基于严格的偶极阻塞效应,将捕获在三个磁光阱中的二能级里德堡原子系综看作超级原子,在此基础上研究原子数目可调控的三体里德堡超级原子的同相和反相动力学行为,同时实现W态和两种最大纠缠态的制备.本工作在量子操控和量子信息处理方面具有潜在的应用前景.  相似文献   
999.
Zhang  Tian-Yi  Li  Chun-Shi  Li  Ping  Bai  Xue-Qian  Guo  Shu-Ying  Jin  Ying  Piao  Sheng-Jun 《Molecular diversity》2022,26(1):27-38

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.

  相似文献   
1000.
CQ Wang  L Wang  CL Fan  DM Zhang  XJ Huang  RW Jiang  LL Bai  JM Shi  Y Wang  WC Ye 《Organic letters》2012,14(16):4102-4105
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   
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