Durable metal-enhanced fluorescence flexible platform by in-situ growth of micropatterned Ag nanospheres

Here, we demonstrate an in-situ growth of micropatterned silver nanospheres(Ag NS) array on transparent polyimide(PI), namely PI-Ag substrate, applied as a flexible platform for metal-enhanced fluorescence(MEF). The scheme proposed here can easily control the grid formation of Ag NSs and the particle size inside, thus achieving patterned fluorescence imaging and MEF efficiency optimization. Meanwhile, the magnitude of enhanced intensity, relying on the distance between Ag NSs and emissive molecules, was systematically investigated by exploring diverse polyethyleneimine(PEI) spacer thickness. Consequently,an optimal enhancement factor of 7.9 and a pattern of grid fluorescence imaging was obtained with an insertion of 10 nm PEI on the PI-Ag(25 nm) platform. Moreover, owing to robust adhesion between Ag NSs and PI film by in-situ growth, this flexible PI-Ag MEF platform maintained a stable MEF efficiency even after taking mechanical bending for 1000 cycles. This new surface-confined micropatterned Ag NSs PI film provides a promising candidate in design flexible MEF platforms for future analytical and clinical sensing applications.     

Possibility for the development of cosmetics with PLGA nanospheres

The optimized preparation of Poly–(lactide-co-glycolic acid) (PLGA) nanospheres containing ubiquinone (UQ) for cosmetic products was pursued. By investigating various conditions for the preparation of UQ/PLGA nanospheres such as the molecular weight of PLGA, PLGA concentration, and UQ concentration, UQ/PLGA nanospheres with increased stability and slower drug release at a higher drug loading efficiency were prepared. Permeation tests on the prepared nanospheres using iontophoresis via electric dermal administration on membrane filters (200?nm pore size) and hairless mouse skin samples were also carried out. After iontophoresis, the nanospheres choked the membrane filter and remained on the horny layer of the hairless mouse skin, even after washing. Therefore, the prepared UQ/PLGA nanospheres and the established iontophoresis technique with the PLGA nanospheres in the present study can be applied to the future development of cosmetics.     

Facile synthesis of Cu--In--Zn--S alloy nanospheres for fast photoelectric detection across the visible spectrum

Fast and broadband photoelectric detection is a key process to many photoelectronic applications, during which the semiconductor light absorber plays a critical role. In this report, we prepared Cu–In–Zn–S (CIZS) nanospheres with different compositions via a facile hydrothermal method. These nanospheres were ~200 nm in size and comprised of many small nanocrystals. A photodetector responded to the visible spectrum was demonstrated by spraying the solution processed nanospheres onto gold interdigital electrodes. The photoelectric characterization of these devices revealed that CIZS nanospheres with low molar ratio of n(Cu)/n(In) exhibited improved photoelectric response compared to those with high n(Cu)/n(In), which was attributed to the reduced defects. The relatively large switching ratio (I_on/I_off), fast response and wide spectral coverage of the CIZS-based photodetector render it a promising potential candidate for photoelectronic applications.     

A highly efficient route for preparing porous magnetic nanospheres with surface-adsorbed quantum dots

Nanoparticles that synchronously exhibit fluorescence and magnetism have great potential in biomedical applications. In this study, porous magnetic nanospheres ranging mainly from 300 to 800?nm in diameter were prepared by spray-drying an ethanol solution containing an ethyl cellulose (EC) polymer and Fe₃O₄ nanoparticles, carried out at lower temperatures (e.g. 40°C). The pores in the nanospheres were mainly caused by the addition of the Fe₃O₄ nanoparticles in the EC precursor. It was found that the more Fe₃O₄ nanoparticles added into the EC precursor, the greater the number and size of the pores in the nanospheres. Positively charged quantum dots (QDs) could be easily adsorbed onto the surface of these porous magnetic nanospheres through a simple electrostatic interaction. It was also found that the greater the porosity of the nanospheres, the more QDs could be adsorbed. The QD-coated magnetic nanospheres obtained are expected to have good multifunctionality due to the synchronous exhibition of bright fluorescence and superparamagnetism. This is a novel, simple and highly efficient method for preparing magneto-fluorescent nanospheres, which are expected to be of considerable interest to material scientists and biologists.     

Ultra-small MoS_2 nanodots-incorporated mesoporous silica nanospheres for pH-sensitive drug delivery and CT imaging

Functionalization of mesoporous silica spheres with well-dispersed and ultra-small nanodots to exert their synergistic effects for biomedical applications has been considered to be an urgent challenge.Herein,homogeneously incorporation of ultra-small and monodispersed MoS₂ nanodots in the mesoporous silica nanospheres(MSN)was achieved by a facile one-step solvothermal reaction.The as-synthesized UsMSND@MSN possessed uniform size(~115 nm)and favorable biocompatibility inherited from MSN.The dispersed UsMSND within MSN could act as anchoring sites for aromatic anti-cancer drug DOX loading,and consequently achieved pH-responsive release based on the specialπ-π/electrostatic interactions with the DOX molecules.More importantly,the well-dispersed UsMSND in MSN could function as the non-toxic contrast agent for the sensitive in vivo CT imaging in various tumors including breast cancer and glioma with different sections.This work promises a good strategy for dispersed incorporation of UsMSND into MSN as an excellent pH-responsive platform for simultaneous cancer imaging and therapy.     

Synthesis and characterization of SiO2-CaO-P2O5 hollow nanospheres for biomedical applications

A ternary system of SiO₂-CaO-P₂O₅ hollow nanospheres has been successfully prepared by sol-gel method using polystyrene (PS) nanospheres as template. The inorganic shell was produced using tetraorthosilicate (TEOS) as the silica source and tri-calciumphospate as calcium and phosphorus sources, respectively. The positive surface charge of the template and the [template]/[TEOS] ratio were the key parameters for the creation of a stable primary inorganic network and the further growth of the shell. The removal of the polymeric core through a thermal treatment procedure created an inner void space with mean diameter 250 nm while the outer mean diameter was 330 nm.     

Polymeric hybrid mesoporous silica hollow nanospheres as a support for palladium and application of the PdNPs@PANI/HNS nanocomposite for aerobic benzyl alcohol oxidation

The polyaniline composition by silica based mesoporous hollow nanosphere (silica-HNS) was synthesized and selected as a promising solid support for palladium nanoparticle stabilization. Then the nanocomposite was applied as a nanocatalyst for aerobic benzyl alcohol oxidation reactions. Catalyst recyclability showed six successful runs for the reaction. TEM and SEM-EDX/mapping images were used to study the structure and morphology of the Pd_NPs@PANI/HNS. FT-IR spectroscopy, Thermal gravimetric analysis (TGA), and BET were used to characterize and investigate the catalyst nature. In addition, the amounts of Pd loading were characterized by ICP-AES technique.     

Biomass derived 5-hydroxymethylfurfural as carbon precursor to form hollow carbon nanospheres for CO2 capture

We prepare the hollow carbon nanospheres (HCNs) by employing SiO₂ nanospheres as hard template, 5-Hydroxymethylfurfural (HMF) as carbon precursor under hydrothermal conditions. The HCNs show uniform spherical morphology copied from SiO₂ nanospheres and exhibit large cavity, thin shell structure with the surface area of 790 m² g^?1 and pore volume of 2.23 cm³ g^?1. Owing to their large internal voids and high surface area, the HCNs exhibit a promising prospect for CO₂ capture with the capacity of 3.04 mmol g^?1 at 1.0 bar and 298 K, as well as good recyclability for CO₂ after ten adsorption-desorption cycles.     

基于多机器人自组织协作的多目标跟踪

提出了一种基于局部区域内的机器人和目标密度的多机器人分布式控制算法。运用这种算法,多机器人在跟踪多目标过程中,每个机器人能在每次调整速度和方向之前,根据最新的通讯信息和感知信息,计算通讯范围内相邻机器人和感知范围内移动目标的数量及位置坐标,然后按照所受人工势场(APF)力的合力决定下一次移动的新位置坐标,这个合力乘以一个基于机器人和目标密度的可变加权系数,以适应不同状态,然后按照动力学和运动学方程计算速度及方向。通过仿真实验对该算法进行了验证,实验结果表明,多机器人可以根据多目标的移动进行自主协作跟踪观测,算法的性能优于无可变加权系数的APF法和静态感知节点(SN)法。此方法对于实时监测和目标跟踪具有实际应用意义。     

一种胶版防伪油墨稀土发光材料制备的研究及应用

目的 制备吡啶二甲酸铕的稀土配合物,将其加入胶版油墨中,并对荧光性能进行检测和分析。方法 以稀土材料Eu盐为主要原料,在一定条件下与2,6-吡啶二甲酸反应形成一种光致发光的稀土配合物,并通过红外光谱和荧光光谱对物质结构进行表征。将合成的稀土配合物添加到白色胶印油墨中,通过印刷适性仪将油墨打印在纸张上。结果 通过荧光检测确定了该物质的主要激发波长为365 nm,发射波长为617 nm;在紫外灯照射下,加入质量分数为3%~4%发光材料的油墨所打印图案的油墨颜色接近于稀土材料的荧光颜色;在D65光源下,该油墨的色度与之前相比变化不大,且可以在加网的条件下完成印刷。结论 稀土发光材料在胶印油墨中发光性稳定,且稀土材料荧光体在油墨中可发光,实现了稀土发光油墨对有机荧光油墨的替代,有利于环境的保护。     

海水介质中碳钢"绿色"缓蚀剂缓蚀过程的研究

采用电化学方法研究了自制的高效、绿色复合缓蚀剂（葡萄糖酸钙、硫酸锌和具有多个配位基团的酯类物质——OCTA）在海水介质中对碳钢的缓蚀作用过程．结果表明,单一的硫酸锌是阴极型缓蚀剂,葡萄糖酸钙和OCTA是阳极型缓蚀剂,复配的缓蚀剂是混合型缓蚀剂．复合缓蚀剂在碳钢表面的成膜过程初步认为是OCTA与葡萄糖酸根离子协同与溶液中金属阳离子发生络合反应,生成三维吸附膜,锌离子在阴极形成氢氧化锌沉淀膜,使得两种缓蚀剂膜优势互补,提高了膜的保护性能．     

Diaphragm cell determination of the interdiffusion coefficient for succinonitrile + water

Using diaphragm cells, we have measured the interdiffusion coefficient for succinonitrile+water in the one-phase liquid region at a series of temperatures ranging form 25 to 60°C and compositions ranging from 34.5 to 96 mol% water. The diffusion coefficient was found to be a function of both temperature and concentration, varying from 1.66×10^–6 to 16.6×10^–6 cm²·s^–1. Critical slowing down of diffusion was readily detected at 60°C (critical temperature, 56.17°C) over a broad range of composition on either side of the critical composition (82.7 mol% water).Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24, 1994, Boulder, Colorado, U.S.A.     

空调热水一体机制冷兼制热水模式的模糊判定

基于目前空调热水一体机在制冷兼制热水模式时,随着水箱温度的不断升高,机组制冷能效比下降和制冷量减少的问题,提出采用以水箱温度为切换点,控制水冷到风冷的切换。以前一日的切换温度和环境温度变化量为输入,当日的切换温度为输出设计模糊判定控制系统,并对其控制效果进行MATLAB仿真。结果表明,以前一日的切换温度和环境温度变化量为依据能够对当日的切换温度作出合适的判定。     

A sensitivity-based coordination method for optimization of product families

This article provides an introduction to a decomposition-based method for the optimization of product families with predefined platforms. To improve the efficiency of the system coordinator, a new sensitivity-based coordination method (SCM) is proposed. The key idea in SCM is that the system level coordinates share variables by using sensitivity information to make trade-offs between the product subsystems. The coordinated shared variables are determined by minimizing the performance deviation with respect to the optimal design of subproblems and constraint violation incurred by sharing. Each subproblem has a significant degree of independence and can be solved in a simultaneous way. The numerical performance of SCM is investigated, and the results suggest that the new approach is robust and leads to a substantial reduction in computational effort compared with the analytical target cascading method. Then, the proposed methodology is applied to the structural optimization of a family of automotive body side-frames.     

An on-line pre-concentration system for determination of cadmium in drinking water using FAAS

In the present paper, a minicolumn of polyurethane foam loaded with 4-(2-pyridylazo)-resorcinol (PAR) is proposed as pre-concentration system for cadmium determination in drinking water samples by flame atomic absorption spectrometry. The optimization step was performed using two-level full factorial design and Doehlert matrix, involving the variables: sampling flow rate, elution concentration, buffer concentration and pH. Using the established experimental conditions in the optimization step of: pH 8.2, sampling flow rate 8.5 mL min(-1), buffer concentration 0.05 mol L(-1) and elution concentration of 1.0 mol L(-1), this system allows the determination of cadmium with detection limit (LD) (3sigma/S) of 20.0 ng L(-1) and quantification limit (LQ) (10sigma/S) of 64 ng L(-1), precision expressed as relative standard deviation (R.S.D.) of 5.0 and 4.7% for cadmium concentration of 5.0 and 40.0 microg L(-1), respectively, and a pre-concentration factor of 158 for a sample volume of 20.0 mL. The accuracy was confirmed by cadmium determination in the standard reference material, NIST SRM 1643d trace elements in natural water. This procedure was applied for cadmium determination in drinking water samples collected from Salvador City, Bahia, Brazil. For five samples analyzed, the achieved concentrations varied from 0.31 to 0.86 microg L(-1).     

Channel coordination for multi-stage supply chains with revenue-sharing contracts under budget constraints

Real-life situations show that revenue-sharing (RS) contracts used in multi-stage supply chains have more complex structures than those that have been studied in recent research. In this paper, we study RS contracts in multi-stage supply chains where some members work with more than one upstream member. This general supply chain structure closely resembles those in actual practice under RS contracts. The literature on supply chain contracts has not adequately addressed contract design for supply chains with members who face budget constraints. We show that the RS contract could fail to coordinate supply chains when members are under particular budget constraints. In response, we propose a revenue-sharing with budget constraints (RSB) contract that adds no administrative cost. A properly designed RSB contract can be used to achieve supply chain coordination and to arbitrarily allocate profits in multi-stage supply chains. Our numerical results provide insights into ways supply chain coordination can be achieved under budget constraints through the RSB contract.     

供应链订货与营销渠道协调的主从对策模型

研究了供应链订货与营销渠道的协调问题,考虑了零售商具有订货成本缩减和营销投资成本,建立了供应链订货与营销渠道协调的Stackelberg主从对策模型.这一模型中,主方零售商具有产品零售价格和投资决策权,从方供应商具有产品批发价格决策权.分析了零售商四种投资策略,针对每种投资策略下的协调模型进行了数值仿真,结果表明在零售商订货成本缩减和营销之间进行投资协调能够同时增加零售商和供应商利润.     

A Universal Synthesis Strategy for Lanthanide Sulfide Nanocrystals with Efficient Photocatalytic Hydrogen Production

As an important lanthanide (Ln)-based functional materials, the Ln chalcogenides possess unique properties and various applications. However, the controllable synthesis of Ln chalcogenide nanocrystals still faces great challenges because of the rather poor affinity between Ln and chalcogenide ions (S, Se, Te) as well as strong preference of combination with existed oxygen. Herein, a facile but general heterogeneous nucleation synthetic strategy is established toward a series of colloidal ternary Cu Ln sulfides nanocrystals using the Ln dithiocarbamates and CuI as precursors. To extend this synthetic protocol, similar strategy is used to prepare six kinds of high quality CuLnS₂ nanocrystals, while the bulk ones are only obtained by the traditional solid-state reaction at rigorous condition. Importantly, high-entropy nanocrystals CuLnS₂ and CuEu_xLn_2-xS₃ which contain six Ln elements (Nd, Sm, Gd, Tb, Dy) are readily obtained by the co-decomposed process attributed to their similar diffusion speed. As a proof-of-concept application, CuEu₂S₃ nanocrystals showed efficient photocatalytic hydrogen production properties.