Four-Wave Mixing of Pulsed Signal in Dispersion-Shifted Fiber With Pump Depletion

The output signal and idler pulses generated by dispersion-shifted-fiber-based four-wave mixing (FWM) with pulsed signal input are analyzed. A set of analytical expressions for the amplitude and phase of the output pulses is derived. Analytical analysis shows that the generated idler pulse is far away from the phase conjugation of the input signal, and that the output signal is not an amplified replica of the input signal. These phenomena are due to both the phase distortion caused by self- and cross-phase modulation and the temporal envelope broadening resulting from pump depletion. Besides, in the frequency domain, the spectral inversion between signal/idler will be destroyed. The implications of the phase and shape distortions in all-optical signal processing by FWM are discussed. The induced phase distortions of idler pulses in dual pumps case are found to be much smaller than those of the single-pump case.     

工程造价师如何在房地产业中发挥作用

工程造价师应从最初只负责施工阶段工程造价的确定和结算,发展成在设计阶段、投资决策阶段,对工程造价做出预测并对设计和施工全过程的造价进行监督和控制,以达到合理使用投资,取得最佳投资效益的目的     

A Versatile Flow-Profile Engineering Method in the Stokes Flow Regime for Complex-Shaped Flows

Flow profiles are frequently engineered in microfluidic channels for enhanced mixing,reaction control,and material synthesis.Conventionally,flow profiles are en...     

Transitional vacuole formation following a bolus infusion of PEG-hemoglobin in the rat

This study was designed to assess the morphological effects of a bolus infusion of PEG-hemoglobin on the heart, lung, liver, spleen and kidney of laboratory rats. Of particular interest was the determination of PEG-hemoglobin's potential to form vacuoles in the tissues and whether these were transitory and article specific. One hundred ten female Sprague-Dawley rats were used in this study. The first experiment determined whether vacuole formation was test article specific by infusing either stroma-free bovine hemoglobin, PEG-hemoglobin, bovine serum albumin, PEG-bovine serum albumin or free PEG. The second experiment assessed the transitory nature of vacuolization. In both experiments, unconscious rats received an intravenous top-loading (bolus) injection of test article via the tail vein. Rats were sacrificed at various time points following administration and had their tissues examined for the presence of vacuoles by light microscope morphological examination and iron staining. Formation of vacuoles appeared to be test article specific with only prolonged circulating, high solute test articles producing vacuoles. These vacuoles appeared dose responsive and transitory in nature. The vacuolization found was non-toxic and believed to be due to the known effect of lysosomal overloading following the phagocytosis of vascularly persistent high solute test articles.     

Analysis for chromium traces in the aquatic ecosystem II. A study of Cr(III) and Cr(VI) in the susquehanna river basin of New York and Pennsylvania

A new procedure for the differential analysis of ppb concentrations of Cr(III) and Cr(VI) in natural waters has been developed. In this method, three-liter samples are filtered, acidified to pH 6.0, and divided into three parts. One liter is passed through an anion-exchange resin bed (AG-1X4, 100–200 mesh, Cl^? form), one liter is passed through a cation-exchange resin bed (50 WX4, 100–200 mesh, Na⁺ form), and one liter remains untreated. 10 ml of 1.0 M HNO₃ are then added to each of the three aliquots and they are individually reduced in volume by evaporation to 10 ml. Analysis by A.A. employing the method of standard addition follows. By difference, cationic, anionic, and non-ionic Cr concentrations in the sample become available. Cr(III) concentration is probably closely related to (cationic + non-ionic), and Cr(VI) concentration in the original sample corresponds to the anionic portion. Precision is ±20 % or better for total, cationic, and anionic Cr at the 1 ppb level. Precision of the non-ionic analyses is closely linked to these other precisions as the concentration of non-ionic Cr species in the original sample is obtained by the mass balance requirement set up by the other three analyses.Application of this technique to the analysis of natural water samples revealed the predominance of trivalent Cr in uncontaminated waters of the Upper Susquehanna River Basin (1–2 ppb). River water samples taken downstream of Binghamton, N.Y. area sewage outfalls revealed an increase in the mean Cr(VI) content of the river from ～0.5 ppb to ～1.6 ppb. The persistence of the Cr(VI) at least as far as 60 km downstream of the outfall area leads to the conclusion that at these levels, little dissolved Cr(VI) is removed from the river as it flows away from a point of contamination. Concentrations of Cr in samples of river sediments also revealed Cr contamination below the outfall area, and Cr contamination extended at least as far as 60 km downstream of the outfall area.     

A 105-nm ultrawide-band gain-flattened amplifier combining C- and L-band dual-core EDFAs in a parallel configuration

A novel structure for ultrawide-band gain-flattened amplifier by combining two pieces of C- and L-band dual-core erbium-doped fibers is reported. This novel amplifier has a flat gain of 15 dB over a wavelength range of 105 nm (1515-1620 nm). The gain variation for the C-band flat gain region (1515-1555 nm) is 1.3 dB, and for the L-band flat gain region (1562-1620 nm) is 1.5 dB. The noise figure varies from 4.5 to 4.8 dB over the whole bandwidth. The structure of the design is simple without the need of additional expensive components.     

Multi‐layer Lattice Model for Real‐Time Dynamic Character Deformation

Due to the recent advancement of computer graphics hardware and software algorithms, deformable characters have become more and more popular in real‐time applications such as computer games. While there are mature techniques to generate primary deformation from skeletal movement, simulating realistic and stable secondary deformation such as jiggling of fats remains challenging. On one hand, traditional volumetric approaches such as the finite element method require higher computational cost and are infeasible for limited hardware such as game consoles. On the other hand, while shape matching based simulations can produce plausible deformation in real‐time, they suffer from a stiffness problem in which particles either show unrealistic deformation due to high gains, or cannot catch up with the body movement. In this paper, we propose a unified multi‐layer lattice model to simulate the primary and secondary deformation of skeleton‐driven characters. The core idea is to voxelize the input character mesh into multiple anatomical layers including the bone, muscle, fat and skin. Primary deformation is applied on the bone voxels with lattice‐based skinning. The movement of these voxels is propagated to other voxel layers using lattice shape matching simulation, creating a natural secondary deformation. Our multi‐layer lattice framework can produce simulation quality comparable to those from other volumetric approaches with a significantly smaller computational cost. It is best to be applied in real‐time applications such as console games or interactive animation creation.