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991.
NA序列经验过程振动模的收敛速度 总被引:2,自引:0,他引:2
许冰 《宁波大学学报(理工版)》1999,12(2):32-36
建立了NA序列经验过程振动模的强收敛速度,类似于独立同分布序列.并把它应用到线性模型,考虑了误差分布的估计. 相似文献
992.
D. Husain J. Lei F. Castao M. N. Snchez Rayo 《Journal of photochemistry and photobiology. A, Chemistry》1999,120(3):151-159
The collisional behaviour of Ba[6s5d(3DJ)], 1.151 eV above the 6s2(1S0) electronic ground state, in the presence of atomic strontium, has been investigated in the ‘long-time domain' (ca. 100 μs–1 ms) following the pulsed dye-laser excitation of barium vapour at elevated temperature at λ = 553.5 nm (Ba[6s6p(1P1)] ← Ba[6s2(1S0)]. Ba(3DJ) is subsequently produced from the short-lived 1P1 state (τe = 8.37 ± 0.38 ns) by a number of radiative and collisional processes. It may then be monitored in the ‘long-time domain' by atomic spectroscopic marker methods involving either collisional activation of Ba(3DJ) by Ba(1S0) and He buffer gas to yield Ba[6s6p(3PJ)] with subsequent emission from the 3P1 state (τe = 1.2 ± 0.1 μs): Ba[6s6p(3P1)] → Ba[6s2(1S0)] + hv (λ = 791.1 nm). Alternatively, emission from Ba(1P1) may be monitored at long times following the generation of this short-lived state by energy pooling following self-annihilation of Ba(3DJ) + Ba(3DJ) from Ba[6s6p(1P1)] → Ba[6s2(1S0)] + hv (λ = 553.5 nm). The generation of Ba(3DJ) in the presence of atomic strontium yields emission in the long-time domain from Sr[5s5p(3P1)] (τe = 19.6 μs): Sr[5s5p(3P1)] → Sr[5s2(1S0)] + hv (λ = 689.3 nm). Whilst the decay profiles at short times are complex in form, at long times all these atomic profiles show first-order kinetic removal with the decay coefficients for λ = 791.1 nm, 689.3 nm and 553.5 nm emissions in the ratio 1 : 2 : 2, consistent with overall third-order activation of the form: Ba(3DJ) + Ba(3DJ) + Sr(1S0) → Sr(3PJ) + 2Ba(1S0). The mechanism is modelled in detail, including measurement of integrated emission intensities, yielding kinetic data for fundamental collisional processes. The overall rate constant for the third-order collisional activation of Sr[5s5p(3PJ])from 2Ba[6s5d(3DJ)] + Sr[5s2(1S0)] takes the upper limit of 5.8 × 10−27 cm6 atom−2 s−1 (T = 900 K). The rate constant for the two body collisional quenching of Ba[6s5d(3DJ)] by ground state atomic strontium, Sr[5s2(1S0)], is found to be (2.0 ± 0.1) × 10−12 cm3 atom−1 s−1 (T = 900 K). 相似文献
993.
Motoaki Kimura Steve Tung James Lew Chih-Ming Ho Fukang Jiang Yu-Chong Tai 《Fluid Dynamics Research》1999,24(6):679-342
Measurements of wall shear-stress streaks of a turbulent boundary layer in the channel flow were carried out using a MEMS-based micro-shear-stress imaging chip, which contains about 100 sensors. The chip is designed and fabricated by surface micromachining technology. One arrray of 25 micro-shear-stress sensors in the chip that covers a length of 7.5 mm is used to measure the instantaneous spanwise distribution of the surface shear stress. The statistics of high shear-stress streaks were established. Based on the measurement, the physical quantities associated with the high shear-stress streaks, such as their length, width and peak shear-stress level, were obtained. We found out that a high correlation exists between the peak shear-stress level and front-end shear-stress slope of a high shear-stress streak. This important property is currently being applied to the deisgn of a real-time flow control logic. 相似文献
994.
995.
Rossetti Manuel D. Clark Gordon M. 《Methodology and Computing in Applied Probability》1999,1(3):247-275
Important performance measures for many Markov renewal processes are the counts of the exits from each state. We present solutions for the conditional first, second, and covariance moments of the state exiting counting processes for a Markov renewal process, and solutions for the unconditional equilibrium versions of the moments. We demonstrate the relationship between the conditional first moments for the state exiting and the state entering counting processes. For analytical and illustrative purposes, we concentrate on the two state case. Two asymptotic expansions for the moment functions are proposed and evaluated both analytically and empirically. The two approximations are shown to be competitive in terms of absolute relative error, but the second approximation has a simpler analytical form which is useful in analyzing more complex stochastic processes having an underlying MRP structure. 相似文献
996.
In this paper we construct models obtained by suitably combining Brownian motions and telegraphs in such a way that their
transition functions satisfy higher-order parabolic or hyperbolic equations of different types.
Equations with time-varying coefficients are also derived by considering processes endowed either with drift or with suitable
modifications of their structure.
Finally the distribution of the maximum of the iterated Brownian motion (along with some other properties) is presented.
This work is partially supported by the Natural Science Foundation of Guangdong Province, National Natural Science Foundation
of China grant No. 19501026 and the Alexander von Humbodlt Foundation 相似文献
997.
998.
Young-Dae Jung 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,11(2):291-294
The classical electron-ion Coulomb Bremsstrahlung process is investigated in nonideal plasmas. An effective pseudopotential
model taking into account the plasma screening and collective effects is applied to describe the electron-ion interaction
potential in a classical nonideal plasma. The classical straight-line trajectory method is applied to the motion of the projectile
electron in order to visualize the variation of the differential Bremsstrahlung radiation cross-section (DBRCS) as a function
of the scaled impact parameter, nonideal plasma parameter, projectile energy, photon energy, and Debye length. The results
show that the DBRCS in ideal plasmas described by the Debye-Hückel potential is always greater than that in nonideal plasmas,
i.e., the collective effects reduce the DBRCS for both the soft and hard photon cases. For large impact parameters, the DBRCS
for the soft photon case is found to be always greater than that for the hard photon case.
Received 1st December 1999 相似文献
999.
The output intensity of optically pumped NH3 molecules far-infrared laser (NH3-OPFIRL) was calculated by solving the density matrix equation and by means of iteration method. Meanwhile, the spectral characteristic of AC Stark splitting was studied. Finally, the F-P interferogram of NH3-OPFIRL pumped by CO2-10R(8) line was measured. The experimental results were in good agreement with the theoretical calculation results. 相似文献
1000.
Yingtan Yu Ying Lyu Ting Zhang Lin Liu Bing Fan Jian Wang Chaoxing Zhang 《Molecules (Basel, Switzerland)》2021,26(21)
Iopromide (IOP), an iodinated X-ray contrast medium (ICM), is identified as a precursor to iodide disinfection byproducts that have high genotoxicity and cytotoxicity to mammals. ICM remains persistent through typical wastewater treatment processes and even through some hydroxyl radical-based advanced oxidation processes. The development of new technologies to remove ICMs is needed. In this work, mackinawite (FeS)-activated sulfite autoxidation was employed for the degradation of IOP-containing water. The experiment was performed in a 500 mL self-made temperature-controlled reactor with online monitoring pH and dissolved oxygen in the laboratory. The effects of various parameters, such as initial pH values, sulfite dosages, FeS dosages, dissolved oxygen, and inorganic anions on the performance of the treatment process have been investigated. Eighty percent of IOP could be degraded in 15 min with 1 g L−1 FeS, 400 μmol L−1 sulfite at pH 8, and high efficiency on the removal of total organic carbon (TOC) was achieved, which is 71.8% via a reaction for 1 h. The generated hydroxyl and oxysulfur radicals, which contributed to the oxidation process, were identified through radical quenching experiments. The dissolved oxygen was essential for the degradation of IOP. The presence of Cl− could facilitate IOP degradation, while NO3− and CO32− could inhibit the degradation process. The reaction pathway involving H-abstraction and oxidative decarboxylation was proposed, based on product identification. The current system shows good applicability for the degradation of IOP and may help in developing a new approach for the treatment of ICM-containing water. 相似文献