高含水率有机质河道底泥压缩性状试验研究

河道底泥的压缩性状是影响河道底泥环保疏浚设计及处置的一个关键因素,采集了4条河道的底泥,针对4种城市河道底泥和过氧化氢处理的底泥开展了一系列物理和压缩试验,研究河道底泥的压缩性状,探讨有机质含量对河道底泥压缩性状的影响规律。试验结果表明,河道底泥的有机质含量变化范围大,河道底泥的压缩性状与底泥的物理性状密切相关,与无机质土类似,初始孔隙比和液限孔隙比是河道底泥压缩性状的两个关键控制因素。有机质对底泥压缩性状的影响可以归结于液限孔隙比的改变,有机质含量主要影响河道底泥的液限和比重,进而导致河道底泥重塑屈服应力σ_(yr)~′和压缩性状发生改变。有机质含量越高,液限孔隙比越大,压缩指数越大,呈现出的压缩性越高。     

Design of a europium-activated lithium-silicate cyan phosphor via cation substitution

Lithium-containing silicates have been considered as a considerable alternative for luminescent materials. In this study, a novel cyan-emitting phosphor, Na₃LiHf₂Si₃O₁₂: Eu²⁺, was successfully synthesized via cationic substitution with Na₄Hf₂Si₃O₁₂: Eu²⁺ as the initial model. The crystal structure, morphology, and luminescence performance of Na_4-xLi_xHf₂Si₃O₁₂: Eu²⁺ were investigated in detail. The substitution of Li⁺ for Na⁺ site causes a significant blue-shift of the emission band in the range of 550–500 nm and a smaller full width at half maximum. As a result, a cyan phosphor Na₃LiHf₂Si₃O₁₂: Eu²⁺ that can be effectively excited by near-ultraviolet and high-energy beams is obtained. The mechanism of emission regulation was proposed based on the transformation of crystal structure and luminescence performance. In addition, the thermal quenching and cathodoluminescence behaviors were also studied. The results show that cation substitution is an effective method to design new lithium-containing silicate phosphors.     

Real-time cutting tool state recognition approach based on machining features in NC machining process of complex structural parts

Cutting tool state recognition plays an important role in ensuring the quality and efficiency of NC machining of complex structural parts, and it is quite especial and challengeable for complex structural parts with single-piece or small-batch production. In order to address this issue, this paper presents a real-time recognition approach of cutting tool state based on machining features. The sensitive parameters of monitored cutting force signals for different machining features are automatically extracted, and are associated with machining features in real time. A K-Means clustering algorithm is used to automatically classify the cutting tool states based on machining features, where the sensitive parameters of the monitoring signals together with the geometric and process information of machining features are used to construct the input vector of the K-Means clustering model. The experiment results show that the accuracy of the approach is above 95% and the approach can solve the real-time recognition of cutting tool states for complex structural parts with single-piece and small-batch production.     

Microwave Sintering of Ti3Si(Al)C2 Ceramic

In this work, microwave sintering (MWS) method was successfully applied for fabrication of dense layered ternary Ti₃Si(Al)C₂ ceramic. Compared to conventional pressureless approaches, MWS could significantly decrease preparation temperature from 1600°C to 1400°C. The activation energy of the MWS process was estimated as 233 ± 18 kJ/mol, which was much lower than those in previous sintering techniques. The low sintering temperature likely originates from the low activation energy during MWS process. Such low temperature do not only make the as‐received Ti₃Si(Al)C₂ ceramic much smaller grain size and better mechanical properties, but also indicate higher energy converting efficiency during the sintering processes. Wide application of MWS techniques in MAX phases is expected to promote the practical applications of these materials and contribute to the energy saving during sintering process.     

LPC2292在微机保护装置中的应用

介绍一种应用于矿井低压电网的智能化保护测控装置,包括它的硬件组成、功能特点以及工作原理。该装置基于LPC2292处理器;有RS485接口／和以太网接口,运行可靠、操作方便、智能化高;可应用于交流50Hz、660／1 140V的中性点不接地的三相电网中,作为配电总开关或分支开关。     

HSDPA的引入策略

首先简述HSDPA承载业务的定位．然后重点从引入方式、组网方式、码资源和功率资源的分配策略等方面分析了HSDPA的引入策略。     

基于硫化铋低温碱性熔炼的熔体物化性质分析

基于硫化铋精矿低温碱性熔炼技术,采用半球点法、旋转柱体法、阿基米德法和拉筒法,测定Bi2S3-NaOH体系的熔化温度、高温密度以及熔体的粘度和表面张力,研究不同NaOH含量和温度对Bi_2S_3-NaOH体系物化性质的影响,结果表明,随着温度的升高,Bi_2S_3-NaOH体系熔化过程分为缓慢收缩,快速收缩和流动阶段,熔化温度随着NaOH含量的增加先减小,达到最低共熔温度后逐渐增大;Bi_2S_3-NaOH熔体的高温密度、表面张力、粘度在NaOH含量一定条件下都随着温度的升高增加而减小,温度一定条件下随着氢氧化钠含量的增加而减小。研究结果可为硫化铋精矿低温清洁冶金技术的优化提供基础数据参考。     

1-L-亮氨酸-1-脱氧-D-果糖和1-L-异亮氨酸-1-脱氧-D-果糖的热裂解分析

采用热重-差热法对1-L-亮氨酸-1-脱氧-D-果糖（Ⅰ）和1-L-异亮氨酸-1-脱氧-D-果糖（Ⅱ）的热失重和热裂解温度进行了研究,通过在线裂解GC-MS联用技术分别对（Ⅰ）和（Ⅱ）在350℃、450℃、550℃、650℃、750℃和850℃条件下的裂解产物进行了鉴定。研究结果表明2种Amadori化合物的的热失重曲线相似,（Ⅰ）的裂解温度为144.67℃,（Ⅱ）的裂解温度为164.26℃,600℃时（Ⅰ）和（Ⅱ）失重约80%;二者裂解产物主要为吡嗪类、吡啶类、吡咯类、喹啉类和呋喃类等杂环化合物,芳香族化合物以及醛类和酮类,其中以吡嗪类为主;裂解产物的数量随着裂解温度的升高而增多,（Ⅰ）的裂解产物数量与（Ⅱ）的裂解产物数量相当。对（Ⅰ）和（Ⅱ）的主要裂解产物形成途径进行了初步探讨,可为研究其在卷烟燃烧过程中的转化行为提供参考。      

高效液相色谱法测定植物甾醇的研究

采用高效液相色谱法测定大豆油脱臭馏出物中的植物甾醇。色谱条件为:以Nova-Pak C18 Column(150mm×4.6mm×5μm)为固定相,流动相为甲醇∶水(体积比为100∶4),检测波长205nm,柱温25℃,流速1.0mL/min,进样量20μL。建立了用超临界CO2萃取技术从大豆油脱臭馏出物中提取的植物甾醇的反相高效液相色谱分析方法。该方法准确、快速、重现性好。