公路工程沥青混合料面层施工技术探讨

近年来，随着我国经济的发展，公路工程也得到了快速发展。公路工程的发展与其施工技术是息息相关的。本文主要就公路工程沥青混合料面层施工技术进行了分析研究。     

九江萍钢铁炼厂低成本生产分析

九江萍钢炼铁厂通过优化配矿,加强基础管理等工作,确保了生产稳定,实现了低成本生铁冶炼。     

Effects of Ultrasonic Waves on Vapor-Liquid Equilibrium of an Azeotropic Mixture

Abstract

Azeotropic and extractive distillation techniques used to separate azeotropic mixtures are among the most challenging separation processes in the chemical industry. In this work, an innovative distillation technique which employed ultrasonic waves was proposed to intensify the conventional multi-column azeotropic distillation method into a single-column alternative. The effects of ultrasonic intensity on the vapor-liquid equilibrium (VLE) of methyl-tert-butyl-ether (MTBE)-methanol was investigated at 50, 100, 200, and 250 W/A·cm² and at a fixed frequency of 40 kHz. Studies were also done to examine the effects of ultrasonic frequency on the VLE data at 25 and 68 kHz frequencies. It was found that ultrasonic waves at 50 W/A·cm² intensity and 25 kHz frequency gave the highest relative volatility (α) at 2.654 and completely eliminated the MTBE-methanol azeotrope, thereby allowing highly pure MTBE to be recovered in just a single distillation column. The results revealed that ultrasonic waves had the potential to favorably manipulate α, and hence, the VLE of an azeotropic mixture.     

Interactive Mixture as a Rapid Drug Delivery System

The effectiveness of an interactive mixture as a rapid drug delivery system is compared with that of a solid dispersion. The influences of drug load, particle size, and crystallinity of these test systems are investigated. The interactive mixtures and solid dispersions were prepared from polyethylene glycol (PEG) 3350 and hydrophobic nifedipine drug by means of physical mixing and melting methods, respectively. The formed products were subjected to drug particle size and crystallinity analyses, and dissolution tests. In comparison with the interactive mixtures, the solid dispersions with low drug load were more effective as a rapid drug delivery system, as the size of a given batch of drug particles was markedly reduced by the molten PEG 3350. The rate and extent of drug dissolution were mainly promoted by decreasing effective drug particle size. However, these were lower in the solid dispersions than in the interactive mixtures when a high load of fine drug particles was used as the starting material. This was attributed to drug coarsening during the preparation of the solid dispersion. Unlike solid dispersions, the interactive mixtures could accommodate a high load of fine drug particles without compromising its capacity to enhance the rate and extent of drug dissolution. The interactive mixture is appropriate for use to deliver a fine hydrophobic drug in a formulation requiring a high drug load.     

Inertization of Coal Ashes by the Vitrification Technique: A Mixture Design Approach

This article deals with the study of the vitrification mechanism as an inertization method for coal ashes contaminated with heavy metals. Ashes from coal (thermoelectric) and wastes from mining of fluorite and feldspar and from plating were used to compose vitreous systems using a mixture design. The chemical composition of the wastes was determined by XRF and the formulations were melted at 1450°C for 2 h using 10% (mass) of Na₂CO₃ (as a fluxing agent). The glasses were poured into a mold and annealed (600°C). The characteristic temperatures were determined by thermal analysis (DTA, air, 20°C/min) and the mechanical behavior by HV. As a result, the softening temperature is strongly dependent on silica content of each glass, and the fluorite residue, being composed mainly by silica, strongly affects on the glass transition (T_g) and softening (T_s) temperatures. The hardness by micro-indentation of all glasses is mainly affected by the plating (galvanic) residue due to the high iron and zinc content of this waste.     

Source cell-phone recognition from recorded speech using non-speech segments

In a recent study, we have introduced the problem of identifying cell-phones using recorded speech and shown that speech signals convey information about the source device, making it possible to identify the source with some accuracy. In this paper, we consider recognizing source cell-phone microphones using non-speech segments of recorded speech. Taking an information-theoretic approach, we use Gaussian Mixture Model (GMM) trained with maximum mutual information (MMI) to represent device-specific features. Experimental results using Mel-frequency and linear frequency cepstral coefficients (MFCC and LFCC) show that features extracted from the non-speech segments of speech contain higher mutual information and yield higher recognition rates than those from speech portions or the whole utterance. Identification rate improves from 96.42% to 98.39% and equal error rate (EER) reduces from 1.20% to 0.47% when non-speech parts are used to extract features. Recognition results are provided with classical GMM trained both with maximum likelihood (ML) and maximum mutual information (MMI) criteria, as well as support vector machines (SVMs). Identification under additive noise case is also considered and it is shown that identification rates reduces dramatically in case of additive noise.     

Improvement in deuterium recovery from water–isotope mixture by thermal diffusion in the device of branch columns

Deuterium recovery from water–isotopes mixture using thermal diffusion can be improved by employing the branch column device, instead of single column devices, with the same total column length. The remixing effect due to convection currents in a thermal diffusion column for heavy water enrichment is thus reduced and separation improvement increases when the flow rate or the total column length increases. The improvement in separation can reach about 50% for the numerical example given.     

A Nifedipine Coground Mixture with Sodium Deoxycholate. II. Dissolution Characteristics and Stability

Nifedipine is a poorly water soluble drug that demonstrates low bioavailability. In a previous study, a coground mixture of nifedipine with sodium deoxycholate (DCNa), a bile salt, immediately produced colloidal particles when dispersed in water. In this study, the effect of the weight fraction of DCNa, grinding time, dissolution media, and storage conditions on colloidal particle formation in solution was investigated. The coground mixture was prepared with a vibration rod mill, and its solid state was characterized using powder X-ray diffraction. A laser diffraction particle size analyzer was used to determine the particle size distribution curve in water. The size of particles formed in solution decreased with an increase in the weight fraction of DCNa and grinding time. A nifedipine-DCNa (1 : 2 w/w) mixture coground for 30 min was used in the experiments. Colloidal particle formation from the coground mixture was also observed in dissolution media of water and a pH 6.8 buffer solution at 37°C. Most precipitates passed through a filter with a pore size of 0.8 μm, but the particle size distribution in water was different from that in the pH 6.8 buffer solution. DCNa exhibited not only micellar solubilization for drug crystals, but also a retarding effect on drug crystal growth in a supersaturated solution. The latter effect could serve to form colloidal particles in solution. When stored under 75% relative humidity at 40°C for 1 month, the amorphous coground mixture crystallized, and the particle size in water markedly increased. Therefore, the weight fraction of DCNa, grinding time, dissolution media, and humidity during storage influence the dissolution characteristics of nifedipine from a coground mixture.     

基于DM8148的警戒区域告警算法的实现

智能视频监控作为安全防范的一种有效手段,有广阔的应用前景。针对这一需求,提出了一种基于DM8148平台的警戒区域告警算法。该算法采用混合高斯模型,结合背景减法检测移动目标,线性预测结合Blob匹配跟踪运动轨迹,分析目标行为判断是否存在警戒区域入侵现象。通过实验验证,该算法所具备的低误报率和高报警精度能满足智能监控对高效率、高实时性要求。