One‐Pot Synthesis of Multifunctional Au@Graphene Oxide Nanocolloid Core@Shell Nanoparticles for Raman Bioimaging,Photothermal, and Photodynamic Therapy

The paper reports a facile one‐pot synthesis of core@shell nanoparticles (NPs) composed of Au core and graphene oxide nanocolloid (GON) shell. Unique properties of Au NPs and GON can be incorporated into a single nanohybrid structure to provide desirable functions for theranosis such as localized surface plasmon resonance, Raman scattering, amphiphilic surface, and photothermal conversion. Synthesis of Au@GON NPs is achieved by simple one‐pot reaction in aqueous phase utilizing GON as a reducing and stabilizing agent without any additional reducing agent. The zinc phthalocyanine, a photosensitizer, loaded Au@GON NPs show excellent multifunctional properties for combinational treatment of photothermal and photodynamic therapy in addition to Raman bioimaging with low cytotoxicity.     

Solution route synthesis of dendrite Cu6Sn5 powders, anode material for lithium-ion batteries

Intermetallic dendrite particles, such as Cu₆Sn₅ compound, possible anode materials for high power lithium-ion batteries, can be synthesized by using solution technique. Solution route method can induce the formation of the compound by performing a redox reaction between metal chloride salts and metallic reducing powder in a suitable solvent. The morphological features and single-phase formation corresponding to different processing conditions including solvent type, reducing agent particle size, and reaction temperature, were determined. The X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) results illustrate the dendritic morphology of Cu₆Sn₅ particles with small amount of impurities, which can be synthesized by using ethylene glycol as solvent and zinc powder as reducing agent. Reducing agent particle size and reaction temperature have a very small effect on the formation of the Cu₆Sn₅ dendrite powder.     

室温条件下纳米银的温和制备和形貌调控

目的 探究室温条件下不同还原剂以及其他实验助剂在化学还原纳米银过程中对其颗粒粒径、尺寸分布和形貌的影响。方法 以抗坏血酸为还原剂,聚乙烯吡咯烷酮（PVP）为分散剂,柠檬酸钠为保护剂和第2还原剂,选择葡萄糖和硼氢化钠作对照,在室温下通过化学还原的方法来制备纳米银颗粒。通过马尔文激光粒度仪、紫外–可见光谱（UV–vis）、透射电镜（TEM）等对所制备纳米银进行表征。结果 采用抗坏血酸作为还原剂时,通过调控抗坏血酸体积（0.2 mL）,固定柠檬酸钠和PVP体积分别为0.5、0.6 mL,制备出粒径较小（平均粒径为56 nm）且尺寸分布较均一的球形纳米银;采用葡萄糖和硼氢化钠作还原剂时纳米银颗粒尺寸过大（平均粒径分别为216nm和189nm）。结论 采用抗坏血酸作为还原剂,调控柠檬酸钠、PVP等实验参数在最佳范围,更容易制备出球形度好、粒径小的均匀纳米银溶液。     

<Superscript>99<Emphasis Type="Italic">m</Emphasis></Superscript>Tc-Oxiracetam as a Potential Agent for Diagnostic Imaging of Brain: Labeling,Characterization, and Biological Evaluation

Oxiracetam was labeled with ^99mTc using sodium dithionite (Na₂S₂O₄) as a reducing agent. The influence exerted on the labeling yield by the amounts of the reducing agent and substrate, pH, temperature, and reaction time was studied to optimize the labeling process. Biodistribution studies show that the ^99mTcoxiracetam complex is suitable as a highly selective tracer for brain imaging.     

Effects of chromium(VI) reducing agents in cement on corrosion of reinforcing steel

During the production of cement it is necessary to add a reducing agent that converts soluble hexavalent chromium into trivalent chromium. This paper explores effects of iron(II) sulphate reducing agents, namely monosulphate and heptahydrate, as cement admixtures, on corrosion of concrete reinforcement. Accelerated corrosion tests of reinforcing steel have been performed in pore solutions simulating concrete prepared using either CEM I or CEM II type cement, with addition of various concentrations of iron(II) sulphate reducing agent. All of the test results indicate corresponding tendencies and point towards the potential for iron(II) sulphate to foster or accelerate corrosion of the reinforcement. The results of this study indicate an immediate need for a more detailed research, especially in concrete as a more realistic corrosion environment, of the application of iron(II) sulphate as a reducing agent in cement.     

Synthesis and characterization of CdS nanoparticles

In the present work a chemical reduction method is followed to grow CdS nanoparticles at room temperature with varying the amount of reducing agent sodiumborohydride. The dispersed samples in ethanol are characterized using electron diffraction techniques. Simultaneously optical absorption, photoluminescence and longtime photorelaxation of these samples are studied at room temperature. An increase in band gap is observed in each case as compared to bulk CdS. Also particle size decreases with increased amount of reducing agent. Simultaneously long time relaxation increases with decrease of stoichiometric ratio of reducing agent. An attempt is made to correlate the structural, optical, electrical and opto-electrical properties.     

Effect of ultrasound radiation on the size and size distribution of synthesized copper particles

The effect of ultrasound radiation on the size and size distribution of synthesized copper particles was investigated under various concentrations of ethylene glycol (E.G.) as a capping agent. Monodispersed copper particles were produced by the reduction of an aqueous copper (II) sulfate solution at the presence of hydrazine monohydrate. X-ray diffraction and scanning electron microscopy analysis revealed that the morphology, size, and size distribution of produced particles were influenced by the reducing agent injection rate, capping agent concentration, and sonication. Increasing the injection rate of reducing agent to an amount higher than a critical value decreases the size of copper particles and also converts the monodispersed particles to polydispersed particles. Results of using a sonifier at the reduction stage revealed that finer monodispersed copper particles can be achieved at higher injection rates related to the critical value. Increasing the concentration of E.G. as a capping agent decreases the size of copper particles, while applying ultrasound radiation along with increasing the concentration of E.G. increases the size of copper particles. Morphology of particles varies by the concentration and type of the capping agent. Higher reducing agent injection rates and the application of a sonifier at the instance of reduction result in smaller spherical particles at various capping agent concentrations.     

Biosynthesis of stabilised gold nanoparticle using an aglycone flavonoid,quercetin

Biosynthesis of gold nanoparticles (AuNPs) was obtained by a simple chemical reduction method using a plant-derived aglycone flavonoid, quercetin, as a reducing agent. The aqueous chloroauric acid when exposed to quercetin was reduced and converted to AuNPs in the size range from 20 to 45?nm. AuNPs were characterised by UV–visual spectroscopy, transmission electron microscopy, atomic force microscopy and dynamic light scattering method. These quercetin-mediated AuNPs have shown excellent stability for more than 30 days at 2–8°C. These quercetin-stabilised AuNPs will have an enormous potential for further conjugation studies since no other external stabilising agent is used.     

Real-time, in-situ, extinction spectroscopy studies on silver-nanoseed formation

In this paper, real-time extinction spectroscopy was employed to analyze in situ the fast formation process of silver seeds. The influencing factors for silver-seed formation, including the concentration of the reducer (NaBH(4)), the amount of stabilizer (citrate), and the addition procedure of NaBH(4), were evaluated. The configuration of the surface plasmon resonance (SPR) spectra of silver nanoparticles, which reflected the morphology of the produced silver seeds, was found to be distinctly affected by the NaBH(4) concentration. Homogeneous silver nanoparticles were obtained when the added NaBH(4) was lower in concentration than 2.00 mM. In contrast, higher concentrations of reducing agent (≥3.00 mM NaBH(4)) resulted in uneven silver nanoparticles. Mie theory was applied to clarify the correlation of the SPR and the size of the silver seeds. Repeated additions of a small amount of the reducing agent could increase the monodispersity and isotropy of silver seeds. Real-time extinction spectroscopy is a convenient technique that achieves the in-situ and nondestructive measurement of intermediates in the formation process of silver nanoseeds.     

纳米铜胶体的合成及表征

以NaBH4为还原剂,表面活性剂CTAB为稳定分散剂,通过化学反应从硫酸铜溶液制备了纳米铜胶体,并研究了稳定分散剂浓度对纳米铜胶体颗粒的氧化、大小及团聚状态的影响.结果表明:当稳定分散剂浓度足够高时,所得纳米铜胶体颗粒大小均匀、分散性好,且能有效地防止颗粒的氧化及团聚.     

On-column derivatization using redox activity of porous graphitic carbon stationary phase: an approach to enhancement of separation selectivity of liquid chromatography

A new on-column derivatization method based on the redox activity of porous graphitic carbon (PGC) packing materials was presented for enhancement of separation selectivity of HPLC. Two PGC packing materials were used as the solid redox agents as well as the stationary phase, and their redox activities were investigated using trans-1,2-diaminocyclohexanetetraacetate (DCTA) complexes of some metal ions as probe compounds. It was found that the redox property of PGC was modified by treating them with a solution containing a reducing agent, sodium sulfite or hydroxylammonium chloride. The original PGC packings oxidized Co(II)-DCTA to Co(III)-DCTA during elution, while the PGC treated with a reducing agent showed reduction activity converting Co(III)-DCTA to Co(II)-DCTA. These two cobalt complexes do not form their individual chromatographic zones but migrate as a single zone of their mixture on the PGC column contrary to the chromatographic behavior on a C18 bonded silica, on which Co(II)-DCTA and Co(III)-DCTA can be separated. Treatment of the PGC column with a reducing agent solution transforms the oxidative activity of the original PGC packing to a reductive one from the upper part of the column, so that the retention time of the cobalt complex can be controlled by changing the volume of the reducing agent solution to be used for treatment of the PGC column. The selective separation and determination of cobalt in a reference manganese nodule sample by the developed method was demonstrated.     

Preparation and characterization of gold nanoparticles using ascorbic acid as reducing agent in reverse micelles

In this study, well-dispersed gold nanoparticles were prepared by the reduction of HAuCl₄ in sodium bis(2-ethylhexyl)sulfosuccinate/isooctane reverse micelles system using ascorbic acid as reducing agent. The properties of the obtained nanoparticles were characterized with transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, and UV–vis absorption spectrophotometer. Due to its high water solubility, biodegradability, and low toxicity, ascorbic acid could be used as a benign naturally available reducing agent to synthesize gold nanoparticles.     

Lead extraction from waste funnel cathode-ray tubes glasses by reaction with silicon carbide and titanium nitride

As a possibility to clean waste CRT glass, treatment of lead-containing glass with a reducing agent, SiC or TiN, leads to a porous material containing metallic lead, Pb(0), located on the surface of the pore, and unreduced lead, Pb(II). The influences of reducing agent content, of the time, and at last of the temperature on lead reduction were analysed. Our investigations have pointed out significant differences as a function of the used reducing agent. CRT glass heat treated with SiC lead to less Pb(0), compared to TiN as shown by X-ray diffraction, and differential scanning calorimetry (DSC). It has been also evidenced that lead reduction occurs on randomized zones inside the sample leading to macroscopic lead beads inside glassy samples. XPS and XAS measurements were also carried out to investigate the local structure of lead and have evidenced a change of role of lead inside the glassy framework in function of the used conditions.     

1,2丙二醇液相还原法制备纳米镍粉的研究

采用有机醇液相还原工艺,用1,2丙二醇作还原剂,制备了晶粒尺寸小于50nm,具有面心立方晶体结构的纳米镍粉,运用XRD,TEM和SAED微观分析手段,研究了还原体系,中间相和NaOH浓度等因素对制备纳米粉的影响,结果表明：与乙醇相比,采用丙二醇作还原剂可获得粒径更小的纳米粉,且可明显缩短反应时间,对醇－水体系和醇溶液两种反应条件下的还原反应的分析表明,反应历程不同,纳米镍粉的纯度和粒度也不同。     

Structural,thermal, zeta potential and electrical properties of disaccharide reduced silver nanoparticles

Silver nanoparticles (AgNPs) have been synthesized using maltose as reducing agent and microwave heating as reaction initiator. The nanoparticles are studied for their optical, structural, thermal, zeta potential and electrical properties. The synthesis protocol used is fast and resulted in the formation of multi-shaped AgNPs as indicated by their optical response and TEM. The crystallite size of nanoparticles and strain of the sample was found to be around 39 nm, and 2.3 × 10^?1, respectively, as calculated from XRD data. Zeta potential and electrical response both showed almost threefold increase for multi-shaped as compared to isotropic nanoparticles.     

嵌段聚醚型减水剂的研制

以奥克公司的新型嵌段聚醚OXAB-505和马来酸酐为主要聚合单体,通过水溶液自由基聚合,合成了一种高效减水剂。本文对马来酸酐用量、醋酸乙烯酯用量、第四聚合单体用量进行了考察,研究了各因素对减水剂应用性能的影响,得出聚醚OXAB-505减水剂最佳合成工艺为：聚醚与马来酸酐的摩尔比为1：2,聚醚与醋酸乙烯酯的摩尔比为1：3,AMPS与聚醚的摩尔比为1：4。     

Synthesis and characterization of FeNi/polymer nanocomposites

Alloyed spherical FeNi-polymer nanocomposites were prepared via wet chemical method using hydrazine as a reducing agent and polymers (PVP and PEG) as reducing and stabilizing agent. Structural studies performed using XRD and TEM shows uniform dispersion of fine FeNi nanocrystallites in nanocomposite particles. The size and thermal stability of FeNi-polymer nanocomposite particles prepared under same reaction condition was found to be dependent on the type and the molecular weight of the polymer used. However, the magnetic properties of nanocomposite particles were not influenced by the polymers. The study highlights subtle differences in using polymers during the synthesis of alloyed nanocomposite particles.     

氨基磺酸盐高效减水剂的研发及复配

采用缩合聚合反应合成了低塌落度损失的氨基磺酸盐高效减水剂。探讨了缩合法生产氨基磺酸盐高效减水剂的工艺过程以及复配对高效减水剂性能的影响。     

高性能水泥基材料的减缩研究进展

系统阐述了混凝土减缩剂的研究进展,详细描述了混凝土自收缩和干燥收缩的机理、减缩剂的作用机理和混凝土的收缩模型,并对国内外混凝土减缩剂的研发应用现状作了整体的评述.     

UV-photoactivation technique for size and shape controlled synthesis and annealing of stable gold nanoparticles in micelle

Gold nanoparticles of different sizes and shapes have been prepared by UV-photoactivation technique using the micelle TX-100 (poly(oxyethylene)iso-octylphenyl ether) as reducing agent, stabilizing agent as well as template which has been authenticated from the plasmon absorption band and TEM picture. The heating effect on those gold nanoparticles has also been studied.