煤粉钝体燃烧器的数值模拟及稳燃机理的研究

本文对煤粉钝体燃烧器中煤粉气流的流动、传热传质和燃烧过程进行了计算机数值模拟,并在实验及计算的基础上,对钝体使煤粉火焰稳定的机理进行了探讨和分析.     

Determination of tectoridin in rat plasma by high‐performance liquid chromatography and its application to pharmacokinetic studies

A simple, specific and sensitive HPLC method with UV detection was developed and validated for the determination of tectoridin in rat plasma for the first time. Chromatographic separation was performed on a Welchrom^TM C₁₈ column (150 × 4.6 mm, i.d., 5 µm) at a flow rate of 1.0 mL min^?1, using a mixture of methanol–2% HAc aqueous solution (31:69, v/v) as the mobile phase with UV detection at 266 nm. The calibration curves for tectoridin were linear over the concentration range of 1.10–274.40 µg mL^?1 in rat plasma. The intra‐ and inter‐day accuracies (RE) were within ?3.23% and 4.11%. The intra‐ and inter‐day precisions (RSD) were not more than 2.74 and 4.72%, respectively. The present method was successfully applied to the pharmacokinetic studies of tectoridin in rats after intravenous administration of three different doses. Copyright © 2009 John Wiley & Sons, Ltd.     

MSVM在汶马高速公路隧道围岩分级中的应用

通过分析国内外的多种围岩分级方法,结合SVM理论与隧道开挖现场实际情况,建立一种快速、准确的隧道围岩分级方法。采用岩石坚硬程度、岩体完整程度、岩体结构、节理风化状况、地下水状况、嵌合程度和地应力状况作为隧道围岩分级评价指标。采用一对一法构建多类分类器,将大量经过专家修正过的隧道围岩分级数据作为多分类SVM的训练学习样本,采用高斯核函数进行计算,结合汶马高速公路隧道施工期围岩分级实践,建立了多分类SVM隧道围岩分级模型,实现不同条件下的围岩分类的合理识别。汶马高速公路隧道围岩分级实际应用表明,该模型能快速、较为准确地进行公路隧道围岩分级。     

夏施~(15)N-尿素在鸭梨树体内的吸收分配规律及其去向的研究

1988～1989年,在田间微区内,研究了夏施~(15)N—尿素在鸭梨树体内的吸收分配规律及其去向。两年结果基本一致。树体吸收~(15)N很快,施肥后仅42d肥料利用率高达8.54％,但向上运转缓慢;当年果实速长期树体中35.9％的肥料氮(NDFF)分配在粗根中,分配到新生器官的仅有29.8％,果实的NDFF浓度为0.087mg/g.dw,比其他器官低得多;在果实生长后期NDFF仍在向果实中运转,长枝的NDFF分配率也持续不降。当年落叶休眠期,树体内的NDFF主要贮藏在多年生枝和粗根中,次年调运到新生器官,用于开花座果及枝叶生长。到次年果实速长期,历经十三个半月,新生器官NDFF的分配率和浓度仍较高。夏施氮肥损失率高达70％以上,微区内土壤残留率低,土壤中残留的NDFF可以上下移动,植株吸收利用率最高仅为8.47％(1988年处理)和14.60％(1989年处理)。     

Boosting Luminance Energy Transfer Efficiency in Upconversion Nanoparticles with an Energy‐Concentrating Zone

Despite the successful application of upconversion nanoparticles (UCNPs), their low energy transfer efficiency is still a bottleneck to further applications. Here we design UCNPs with a multilayer structure, including an inert NaYF₄:Gd core and an energy‐concentrating zone (ECZ), for efficient energy concentration. The ECZ is composed of an emitting layer of NaYF₄:Yb,Er and an absorption layer of NaYF₄:Nd,Yb with antenna IRDye 800CW to manipulate the energy transfer. The stable and tight packing of 800CW linked originally with a bisphosphonate ligand improves greatly the transfer efficiency. The proximity of the emitting layer to both surface antenna and accepter also decreases energy depletion. Compared to classical UCNPs, the ECZ UCNPs show 3600 times higher luminescence intensity with an energy transfer efficiency near 60 %. In proof‐of‐concept applications, this type of structure was employed for Hg²⁺ detection and for photodynamic therapy under hypoxic conditions.     

Influence of the dissolution rate on the collapse and shedding behavior of monostearin/monopalmitin-rich coated microbubbles

A low cost food grade emulsifier (a mixture of monoglycerides, diglycerides, and sodium stearoyl lactylate) in combination with polyethylene glycol-40 stearate (PEG-40S) was used as an alternative to pure saturated phospholipids to form the thin shell of a microbubble. To investigate the stability of these microbubbles in a water system over time, their dissolution behavior was studied at various degas factors and at two percentages of PEG-40S. It was found that the favored shell collapse/shedding mechanism switched, as the dissolution rate increased (degas factor decreased), from folding with a smooth surface contour to buckling accompanied by surface folding/expulsion with a cyclic buckled-smooth surface contour. The compositional change that we made played a more minor role, mainly controlling the resistance to mass transfer of the microbubble shell and again modifying the mechanism-determinant dissolution rate. The shell resistance behavior for these microbubbles varied from that of previous lipid/PEG-40S-coated microbubbles by the presence of a maximum in shell resistance during dissolution. We hypothesize that the dominance of one collapse mechanism over another for these compositions is related to the time scales of two competing processes, fold nucleation and area compression. For these mixtures at room temperature, we estimate that the maximum area compression rate for folding as the major collapse mechanism is approximately 0.2 s (-1), a rate unattainable in a traditional Langmuir trough but achievable by the use of a dissolving microbubble.     

一种新型的涂丝钙离子场效应敏感器件

从1970年以来,不少学者对场效应敏感器件(简称ISFET)做了研究^[1-4],本文作者利用二-(二异辛基苯基磷酸)钙为电活性物质研制成Ca²⁺-ISFET,并测定了器件的各项性能参数。     

Preparation of Silica Aerogel/Resin Composites and Their Application in Dental Restorative Materials

As the most advanced aerogel material, silica aerogel has had transformative industrial impacts. However, the use of silica aerogel is currently limited to the field of thermal insulation materials, so it is urgent to expand its application into other fields. In this work, silica aerogel/resin composites were successfully prepared by combining silica aerogel with a resin matrix for dental restoration. The applications of this material in the field of dental restoration, as well as its performance, are discussed in depth. It was demonstrated that, when the ratio of the resin matrix Bis-GMA to TEGDMA was 1:1, and the content of silica aerogel with 50 μm particle size was 12.5%, the composite achieved excellent mechanical properties. The flexural strength of the silica aerogel/resin composite reached 62.9546 MPa, which was more than five times that of the pure resin. Due to the presence of the silica aerogel, the composite also demonstrated outstanding antibacterial capabilities, meeting the demand for antimicrobial properties in dental materials. This work successfully investigated the prospect of using commercially available silica aerogels in dental restorative materials; we provide an easy method for using silica aerogels as dental restorative materials, as well as a reference for their application in the field of biomedical materials.     

金属氧化物非线性电阻小电流区等值电路研究

提出了MOV的小电流区等值电路以及定量决定等值电路动态参数的方法.利用所提出的等值电路,不但能更好地定性解释MOV的宏观特性规律,而且可以定量计算.