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21.
22.
A relationship between the structure and water purifying ability of waste glass prepared from household garbage and Fe2O3 was examined by 57Fe-Mössbauer and induced coupled plasma (ICP) measurements. From the Debye temperature of waste glass, FeII proved to be loosely bound in the glass network as a network modifier. Dissolution amount of FeIII into artificial drain can be controlled from 0.14 to 0.35 mg/l by changing the Fe2O3 content. It proved that chemical oxygen demand (COD) decreases in proportion to the content of FeIII, indicating that iron causes decomposition of organic and phosphorus compounds.  相似文献   
23.
In order to meet the requirements necessary for advanced optical fiber transmission schemes that enable larger transmission capacity, higher efficiency and/or lower transmission costs per bit, optical fiber technologies are still evolving toward ultimate performance. Recent developmental activities have realized a number of improved performance optical fibers, such as ultra-low loss or ultra-low nonlinearity fibers and various types of dispersion-modified fibers. Fiber-based dispersion compensators or dispersion compensating fibers have also become one of the most essential optical components that support high-speed large capacity optical transmission. Very recently, the dispersion compensating fibers have further evolved into dispersion-managed optical transmission lines, which are now being actually deployed in transoceanic submarine optical cable networks.  相似文献   
24.
The temperature-frequency dependences of the permittivity of crystals of lithium heptagermanate Li2Ge7O15 doped with Cr3+ ions are investigated. A dielectric response to reorientation of the dipole moments of the chromium impurity centers is revealed. Anomalies of the permittivity are described within the model of a Debye relaxator.  相似文献   
25.
This paper is concerned with the competitive-diffusive systems
ut=dluxx+(al?blu?clv)uvt=d2vxx+(a2?b2u?c2u)v(x, t) ? (0, 1) × (0, ∞)
, with homogeneous Dirichlet boundary conditions. From a global bifurcation view point, the dependency of steady-states on the parameters ai, bi, ci and di (i = 1, 2) is investigated. In particular, bifurcation of coexist ence solutions amd their stabilities are our main interests.  相似文献   
26.
The purpose of this project was to assess the reliability of the cerebral mean transit time (MTT) obtained using perfusion-weighted MR imaging by comparing it with the MTT obtained when performing positron emission tomography (PET). Ten patients with chronic occlusive cerebrovascular disease were investigated. They had either unilateral internal carotid artery occlusion or middle cerebral artery occlusion. The regions-of-interest were placed in non-infarcted areas within the territory of the middle cerebral artery on the affected side. Control regions-of-interest were placed in mirrored regions of the contralateral side. Linear regression analyses were performed using the parameters of the MTT obtained with perfusion-weighted MR imaging and the MTT, cerebral blood flow, vascular reactivity, and oxygen extraction fraction obtained with PET. The respective MTTs of the affected and non-affected sides obtained with perfusion-weighted MR imaging versus those with PET were 7.3 +/- 2.2 s and 6.0 +/- 1.2 s versus 8.2 +/- 3.0 s and 6.4 +/- 1.7 s. The MTT obtained using perfusion-weighted MR imaging and PET demonstrated statistically significant correlation (r = 0.87, p < 0.0001). The MTT obtained with perfusion-weighted MR imaging correlated statistically with cerebral blood flow (r = -0.74, p < 0.001), vascular reactivity (r = -0.73, p < 0.001) and oxygen extraction fraction (r = 0.61, p < 0.01). Similarly, the MTT obtained using PET statistically correlated with cerebral blood flow (r = -0.78, p < 0.0001), vascular reactivity (r = -0.51, p < 0.05) and oxygen extraction fraction (r = 0.68, p < 0.01). The reliability of the MTT obtained using perfusion-weighted MR imaging appears to be approximately equal to that obtained with positron emission tomography.  相似文献   
27.
We have investigated the transient characteristics of discrete Raman Amplifiers and found that the response time caused by gain saturation is dependent upon the wavelength, which corresponds to the effective length of the pump light.  相似文献   
28.
We demonstrate the direct generation of 12 fs pulses from a Ti:sapphire regenerative amplifier system at a 1 kHz repetition rate utilizing properly designed broadband components for chirped-pulse amplification. Optimized designs of a regenerative amplifier with a multilayer gain-narrowing compensator and an adaptive dispersion compensator with a spatial light modulator contribute to the shorter pulse amplification.  相似文献   
29.
Ganeev RA  Suzuki M  Baba M  Kuroda H  Ozaki T 《Optics letters》2006,31(11):1699-1701
We report the demonstration of strong resonance enhancement of a single high-order harmonic in the extreme ultraviolet (XUV) region generated from the interaction of a femtosecond pulse with low-ionized In ablation. A strong 13th harmonic (61.2 nm) of Ti:sapphire laser radiation with output intensity almost two orders of magnitude higher than neighboring harmonics was observed in these studies. The high conversion efficiency of the 13th harmonic (8 x 10(-5)) is attributed to multiple collisions of electron trajectories with the origin due to multiphoton resonance with the In ion.  相似文献   
30.
This study investigates the vertical localization of single complex tones (monads) and simultaneous complex tone pairs (dyads), especially as it is affected by their fundamental frequency and source elevation. Two complex tone timbres are considered: one consisting of five low-order harmonics, and the other of all odd harmonics (a square wave). Sound sources were at -15, 0, 15, and 30 deg from the horizontal plane at ear height. For eight subjects, this source array was in the median plane, and for a further nine subjects, it was directly to the subject's left (lateral plane). The subjects localized the angle of the auditory image(s) of one or two complex tones around the vertical plane containing the sound sources. Mean responses for the five-harmonic complex tones show a systematic effect (referred to as Pratt's effect) of fundamental frequency on vertical localization--whereby high-frequency complex tones are localized to positions higher than low-frequency complex tones for equivalent source positions. For the square wave, the sound-source position dominates localization, although some effect of fundamental frequency is evident for median plane sources.  相似文献   
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