上证综合指数波动情况研究——基于滚动窗口的马尔科夫链预测模型

文章运用基于滚动窗口的马尔科夫链预测模型,对上证综指的变动进行研究,创新的给出概率转移矩阵、极限概率以及预测准确率的时变特征,并给出马尔科夫链预测模型的最优窗口长度和状态定义阀值。研究揭示,大盘波动幅度与大盘的极限概率有着密切的关系;股指期货推出后大盘平盘概率占据主导地位,平稳性显著提高,马尔科夫链预测模型的预测准确率也有了较大提高。     

气动振动式匀种装置工作参数的优化及试验

为了提高杂交稻在低播种量时的播种性能,对水稻秧盘育秧精密播种机气动振动匀种装置进行了理论分析和试验研究。通过振动分析确定了振动匀种装置稳定均匀排种的条件。采用正交试验方法,研究了播种量分别为45g/盘、65g/盘和85g/盘时,气源排储比A、V-T振盘筛分板的梯形半差C和安装角β对播种合格率和空穴率的影响规律,得到3种播种量的最佳参数组合分别为气源排储比A为0.036/40,梯形半差C为5mm,安装角β分别为-4°、0°、+4°。最佳参数组合下的试验结果表明:播种量为45g/盘、65g/盘和85g/盘时的播种合格率分别为88.33%、90.83%和93.06%,空穴率分别为1.67%、0.56%和0%,播种性能能够满足超级杂交稻和杂交稻低播种量精密播种的技术要求。     

城市规划环评中公众参与的法律价值分析

用法律价值分析法研究城市规划环评公众参与制度,对我国城市规划环评制度的完善具有积极的意义。我国城市规划环评的公众参与制度是以提高环评的科学性、保障公民合法权益、维护环境正义为价值目标。然而现行制度中还存在着许多诸如立法层次低、参与主体不明确、参与方式有限、信息公开制度不健全、司法救济制度不完善等不利于实现前述法律价值目标的缺陷。为此,在法律实践中立法机关应当采取如转变法律价值观念、提高立法层次、明确参与主体、规范参与方式、健全信息公开制度、构建司法救济制度等措施来完善公众参与制度,以实现其应有的法律价值。     

基于路面使用性能评价的车辙指标研究

文章基于现有沥青路面使用性能评价规范和标准,运用简化的车辙积水模型,围绕高速公路沥青路面车辙深度主观评价标准,针对现有车辙评价模型的不足,通过采用Sigmoid函数,主要探索了车辙深度指数RDI评价模型。结果表明:结合求解的车辙内不致积水的临界车辙深度,将路面车辙深度等级划分为更精细的"轻、中、重"三个等级更加合理;优化的沥青路面车辙深度指数RDI评价模型弥补了现有车辙评价指标的不合理性;在保留现有车辙深度指数评价模型的同时,通过分析路面车辙槽的几何特征增加了车辙的其他指标,初步构建了车辙综合评价模型,对全面评价车辙的危害性及进行路面车辙的养护管理更具有实际意义。     

PPNCast：一种基于对等交换的应用层组播方法*

针对高码率和实时性要求不高的大规模媒体分发应用,提出一种新的应用层组播PPNCast。PPNCast基于对等交换的思想对应用层组播系统进行了优化,可以支持多种片的分发模型。通过仿真实验与Yoid、NICE应用层组播协议对比,结果显示PPNCast可以明显改善系统的链路压力均衡度和节点公平度。     

枪黑色氮钛膜层性能研究

详细介绍枪黑色氮钛膜层的耐磨损及耐腐蚀性能,并和传统的氧化黑色膜层和磷化黑色膜层作了比较,枪黑色氮钛膜层的耐磨损及耐腐蚀性能均高于氧化黑色膜层和磷化黑色膜层3倍以上,是一种比较先进和理想的新型膜层,为离子镀技术开辟了新的应用途径。     

Enhancing oil–solid and oil–water separation in heavy oil recovery by CO2-responsive surfactants

Interfacial properties are of critical importance to various separation applications. In heavy oil recovery, for example, a low oil–water interfacial tension (IFT) benefits the separation of heavy oil from their host rocks, which becomes problematic in the later stage of oil–water separation. CO₂-responsive surfactants were investigated to enhance the overall heavy oil recovery by switching their interfacial activity to the desired state in each stage. The surfactants at interfacially active state greatly enhanced the separation of heavy oil from hosting solids, as demonstrated by measuring contact angle and oil liberation using a custom-designed on-line visualization system. Meanwhile, the resulting heavy oil-in-water emulsions could also be easily demulsified by the bubbling of CO₂ gas, which switched off the interfacial activity of the surfactants. Furthermore, CO₂-responsive surfactants could be partially recycled in process water to improve sustainability, making CO₂-responsive surfactants to be promising chemical aids in heavy oil production and many other vital industries.     

High efficient separation of olefin from fluid catalytic cracking naphtha: Separation mechanism and universal simulation method

The fluid catalytic cracking (FCC) naphtha critical component-oriented separation process is an efficient method to produce ultra-low-sulfur (<10 μg/g) gasoline with minimal loss of octane number (<1 RON). However, the product quality is highly dependent on the structure of the components of FCC naphtha. Aromatics and thiophene sulfides without a methyl side chain favor the separation of olefin. The major impulse of olefin separation is the solvent-induced dipole of aromatics or thiophene sulfides, leading to a “Plane-to-Plane” combination between the solvent and aromatics or thiophene sulfides, accompanied by a steric hindrance due to their side chains. This condition resulted in 2–3 times greater θ of benzene and thiophene compared with that of toluene and 3-methylthiophene. In addition, an improved non-random two-liquid model was proposed based on the above results, and a simulation method for FCC naphtha solvent extraction process was established. The calculation results accorded well with industry data.     

Non-coalescence and chain formation of droplets under an alternating current electric field

The dynamic behaviors of two droplets and droplet cluster under an alternating current (AC) electric field are investigated. Two droplets generally undergo transformation from complete coalescence to partial coalescence and finally to non-coalescence as the electric capillary number Ca_p increases. The critical electric capillary number Ca_pc for complete coalescence in the AC electric field remains unchanged and is twice as large as that in the direct current (DC) electric field when the frequency f ≥ 250 Hz. Charge transfer and reversal of electric field result in the reversal of the direction of electric force, which is the fundamental mechanism of non-coalescence of two droplets and chain formation in droplet cluster. The number of rebounds dramatically increases as f increases, promoting the stability of droplet chain. The droplet chains in the high-frequency AC electric field are longer and more stable than those in the low-frequency AC electric field.     

Full color white light,temperature self-monitor,and thermochromatic effect of Cu+ and Tm3+ codoped germanate glasses

Lighting sources with full-color visible output are widely preferred in practical applications. In addition, modern lighting sources also tend to be intelligentized, and the intelligentization asks for smart luminescence materials. In this work, we attempt to develop novel full-color emitting material with temperature sensing and thermochromatic ability. To this end, the Cu²⁺ is successfully reduced to Cu⁺ which is incorporated into the germanate glasses. The glasses are prepared via a melt-quenching technique using graphite powders as reducing reagent. The supper-broadening of the excitation and the emission spectra of Cu⁺ in the germanate glasses are observed. Full-color emission is realized by introducing Tm³⁺ as co-dopant to provide the blue component in the spectra. The energy transfer behavior between Cu⁺ and Tm³⁺ is investigated, and it is found that these two luminescence centers are independently existent without energy transfer between them. The chromatic properties of the Cu⁺/Tm³⁺ co-doped glasses are tuned by Tm³⁺ concentration and excitation wavelength. The temperature sensing based on the fluorescence intensity ratio technique is demonstrated, and a constant sensitivity for the temperature detection is obtained. Moreover the thermochromatic property is also investigated, and it is found that the studied Cu⁺/Tm³⁺-doped glasses exhibit excellent thermochromatic performance.