预歧化处理的高性能锂离子电池SiO/C负极材料

以SiO和蔗糖为原料,SiO经高温歧化反应处理后,通过机械球磨、喷雾干燥、高温热解工艺制备出具有优异电化学性能的锂离子电池SiO/C负极材料。经XRD、FTIR、XPS、SEM、TEM结构分析表明,歧化反应处理的片状SiO包含非晶态SiO和纳米晶相Si、SiO_2,蔗糖热解形成的无定形碳包覆在细片状SiO的表面,组成球形SiO/C颗粒。电化学测试结果表明,预歧化处理的SiO/C复合材料的首次放电容量为1 314.6mAh/g,首次库伦效率达到71%;100周循环后的放电容量为851.2mAh/g,容量保持率达到78.5%,循环稳定性远高于未经歧化处理的SiO/C复合材料。电化学性能的提高归因于SiO预歧化反应及热解碳包覆。     

Reproducible Enhancement of Fluorescence by Bimetal Mediated Surface Plasmon Coupled Emission for Highly Sensitive Quantitative Diagnosis of Double‐Stranded DNA

Plasmonic enhancement of fluorescence from SYBR Green I conjugated with a double‐stranded DNA (dsDNA) amplicon is demonstrated on polymerase chain reaction (PCR) products. Theoretical computation leads to use of the bimetallic (Au 2 nm–Ag 50 nm) surface plasmons due to larger local fields (higher quality factors) than monometallic (Ag or Au) ones at both dye excitation and emission wavelengths simultaneously, optimizing fluorescence enhancement with surface plasmon coupled emission (SPCE). Two kinds of reverse Kretschmann configurations are used, which favor, in signal‐to‐noise ratio, a fluorescence assay that uses optically dense buffer such as blood plasma. The fluorescence enhancement (12.9 fold at maximum) with remarkably high reproducibility (coefficient of variation (CV) < 1%) is experimentally demonstrated. This facilitates credible quantitation of enhanced fluorescence, however unlikely to obtain by localized surface plasmons. The plasmon‐induced optical gain of 46 dB due to SPCE‐active dye molecules is also estimated. The fluorescence enhancement technologies with PCR enables LOD of the dsDNA template concentration of ≈400 fg µL^?1 (CV < 1%), the lowest ever reported in DNA fluorescence assay to date. SPCE also reduces photobleaching significantly. These technologies can be extended for a highly reproducible and sufficiently sensitive fluorescence assay with small volumes of analytes in multiplexed diagnostics.     

DOC‐LS,a new liposome for dermal delivery,and its endocytosis by HaCaT and CCC‐ESF‐1 cells

The main objective of this work was to investigate the uptake channels of skin cells through which coumarin 6, transported by deoxycholate‐mediated liposomes (DOC‐LS), was internalised; this was also compared against the action of conventional LS. Coumarin 6‐loaded DOC‐LS and LS were characterised for size distribution, zeta potential, and shape, and analysed in vitro in human epidermal immortal keratinocyte (HaCaT) (epidermal) and human embryonic skin fibroblast (CCC‐ESF‐1) (dermal) cell lines. Various endocytosis inhibitors were incubated with cells treated with the nanocarriers. Flow cytometry results indicated that HaCaT and CCC‐ESF‐1 cells internalise the tested preparations through pinocytotic vesicles, macropinocytosis, clathrin‐mediated endocytic pathways, and via lysosomes, which consume a considerable amount of energy. The endocytosis pathways of DOC‐LS and LS showed no difference. This study provides a basis for the application of LS being combined with a microneedle system for efficient intracellular drug delivery, targeting cutaneous histocyte disorders.Inspec keywords: drugs, nanoparticles, lipid bilayers, nanomedicine, biomedical materials, electrokinetic effects, biomembrane transport, drug delivery systems, skin, organic compoundsOther keywords: dermal delivery, CCC‐ESF‐1 cells, skin cells, deoxycholate‐mediated liposomes, coumarin 6‐loaded DOC‐LS, endocytosis inhibitors, clathrin‐mediated endocytic pathways, endocytosis pathways, HaCaT cell lines, size distribution, zeta potential, nanocarriers, flow cytometry, pinocytotic vesicles, macropinocytosis, microneedle system, efficient intracellular drug delivery, targeting cutaneous histocyte disorders     

Integratable non-clogging microconcentrator based on counter-flow principle for continuous enrichment of CaSki cells sample

This study addresses the need to reduce the risk of clogging when preparing samples for cell concentration, i.e., the CaSki Cell-lines (epidermoid cervical carcinoma cells). Aiming to develop a non-clogging microconcentrator, we proposed a new counter-flow concentration unit characterized by the directions of penetrating flows being at an obtuse angle to the main flow, due to employment of streamlined turbine blade-like micropillars. Based on the optimization results of the counter-flow unit profile, a fractal arrangement for the counter-flow concentration unit was developed. A counter-flow microconcentrator chip was then designed and fabricated, with both the processing layer and collecting layer arranged in terms of the honeycomb structure. Visualized experiments using CaSki cell samples on the microconcentrator chip demonstrated that no cell-clogging phenomena occurred during the test and that no cells were found in the final filtrate. The test results show an excellent concentration performance for the microconcentrator chip, while a concentrating ratio of >4 with the flow rate being below 1.0 ml/min. As only geometrical structure is employed in the passive device, the counter-flow microconcentrator can be easily integrated into advanced microfluidic systems. Owing to the merit of non-clogging and continuous processing ability, the counter-flow microconcentrator is not only suitable for the sample preparation within biomedical field, but also applicable in water-particle separation.     

公交信号优先策略研究

本文介绍了公交优先策略的概念和分类,阐述了绿灯延长、绿灯提前、相位倒转、相位插入、公交通行专用相位等主动优先控制策略的基本原理,并对其进行了适应性和优缺点分析。     

Visual comparability of 3D regular sampling and reconstruction

The Body-Centered Cubic (BCC) and Face-Centered Cubic (FCC) lattices have been analytically shown to be more efficient sampling lattices than the traditional Cartesian Cubic (CC) lattice, but there has been no estimate of their visual comparability. Two perceptual studies (each with N = 12 participants) compared the visual quality of images rendered from BCC and FCC lattices to images rendered from the CC lattice. Images were generated from two signals: the commonly used Marschner-Lobb synthetic function and a computed tomography scan of a fish tail. Observers found that BCC and FCC could produce images of comparable visual quality to CC, using 30-35 percent fewer samples. For the images used in our studies, the L(2) error metric shows high correlation with the judgement of human observers. Using the L(2) metric as a proxy, the results of the experiments appear to extend across a wide range of images and parameter choices.     

Unsteady development of a deformable bubble rising in a quiescent liquid

An accurate finite-volume based numerical method for the simulation of an isothermal two-phase flow, consisting of a rising deformable bubble translating in a quiescent, unbounded liquid, is presented. This direct simulation method is built on a sharp interface concept and developed on an Eulerian, Cartesian fixed-grid with a cut-cell scheme and marker points to track the moving interface. The unsteady Navier–Stokes equations in both liquid and gas phases are solved separately. The mass continuity and momentum flux conditions are explicitly matched at the true surface phase boundary to determine the evolving interface shape and movement of the bubble. The highlights of this method are that it utilizes a combined Eulerian–Lagrangian approach, and is capable of treating the interface as a sharp discontinuity. A fixed underlying grid is used to represent the control volume. The interface, however, is denoted by a separate set of marker particles which move along with the interface. A quadratic curve fitting algorithm with marker points is used to yield smooth and accurate information of the interface curvatures. This numerical scheme can handle a wide range of density and viscosity ratios. The bubble is assumed to be spherical and at rest initially, but deforms as it rises through the liquid pool due to buoyancy. Additionally, the flow is assumed to be axisymmetric and incompressible. The bubble deformation and dynamic motion are characterized by the Reynolds number, the Weber number, the density ratio and the viscosity ratio. The effects of these parameters on the translational bubble dynamics and shape are given and the physical mechanisms are explained and discussed. Results for the shape, velocity profile and various forces acting on the bubble are presented here as a function of time until the bubble reaches terminal velocity. The range of Reynolds numbers investigated is 1 < Re < 100, and that of Weber number is 1 < We < 10.     

IEEE 802.16网状网络中基于队列的带宽分配

IEEE 802.16网状网络中分布式调度的建立时间对时延敏感类业务影响较大。针对该问题,使用基于令牌分发的循环轮转服务机制向邻居节点请求或授予带宽,预测调度控制消息发送间隔内到达的数据包量,据此完成三次握手过程,保证业务流公平带宽分配并减小数据包因为三次握手过程造成的队列缓冲时延。NS2仿真实验验证了该算法的有效性。